Talks
in 2009
Isao Sugai
KEK
Abstract
The newly developed Hybrid Boron mixed Carbon (HBC) foils have been used and tested at the RCS of J-PARC since September of 2007. Two foils approximately 100 microgram per square cm each are sandwiched together to form an equivalent 200 microgram per square cm foil. The sandwiched foil is supported by ~10 micron diameter SiC fibers attached to one-edge titanium target frame. These foils show no problem because of very low foil temperature due to low beam power of 20 kW for stripping of 180 MeV H- ion beam at present. However, the final goal of the beam power will be about 1 MW in near future. For that purpose, we are developing the HBC foils that will have high durability at 2000 K. We will present the foil preparation and lifetime measurements of the HBC, diamond, DLC and CM foils for comparison. Three different ion beam irradiations were used: 3.2 MeV Ne+ DC beam, 650 keV H- DC beams, and 800 MeV H- pulsed beam at the PSR of Los Alamos National Laboratory. The former two beams have almost the same energy deposition as that of the beam at J-PARC.
Bill Ng
Fermilab
Abstract
This is a lecture on wake functions and impedances. The lecture includes the Panofsky-Wenzel Theorem, definitions of wake functions and impedances, space-charge impedances, resistive-wall impedances of thin and laminated vacuum chamber, impedances of BPMs, cavities, and others. Most expressions will be derived in detail.
Allen Caldwell
Max Planck Institute for Physics in Munich
Abstract
Investigations into frictional cooling for producing a cold muon beam
A high luminosity muon collider will require six orders of magnitude
reduction in the phase space volume between the production of the
muons and injection into the collider ring. Novel techniques must be
developed to achieve this reduction within the lifetime of the muon.
One possible approach is 'frictional cooling', where muons are
decelerated to energies below the Bragg peak, brought to an
equilibrium energy, and then reaccelerated. Simulation studies will
be presented, as well as the status of an experimental demonstration
of the frictional cooling process.
Proton driven plasma wakefield acceleration
Plasma wakefield acceleration, either laser driven or electron-bunch
driven, has been demonstrated to hold great potential. However, it is
not obvious how to scale these approaches to bring particles up to the
TeV regime. We discuss the possibility of proton-bunch driven plasma
wakefield acceleration, and show that high energy electron beams could
potentially be produced in a single accelerating stage starting from a
high energy proton beam.
Presentation
Yipeng Sun
CERN
Abstract
Modern colliders bring into collision a large number of bunches to
achieve a high luminosity. The long-range beam-beam effects arising
from parasitic encounters at such colliders are mitigated by
introducing a crossing angle. Under these conditions, crab cavities
(CC) can be
used to restore effective head-on collisions and thereby to increase
the geometric luminosity. Such crab cavities have been proposed for
both linear and circular colliders. The crab cavities are RF cavities
operated in a transverse dipole mode, which imparts on the beam
particles a transverse kick
that varies with the longitudinal position along the bunch. The use of
crab cavities in the Large Hadron Collider (LHC) may not only raise
the luminosity, but it could also complicate the beam dynamics, e.g.
crab cavities might not only cancel synchro-betatron resonances
excited by the crossing angle but they could also excite new ones,
they could reduce the dynamic aperture for off-momentum particles,
they could influence the aperture and orbit, also degrade the
collimation cleaning efficiency, and so on. In this paper, we explore
the principal feasibility of LHC crab cavities from beam-dynamics
point of view. The implications of the crab cavities for the LHC
optics, analytical and numerical luminosity studies, dynamic aperture,
aperture and beta-beating, emittance growth, beam-beam tune shift,
long-range collisions, and synchro-betatron resonances, crab
dispersion and collimation efficiency will be discussed.
Luisa Chiesa
Tufts University
Abstract
Since its discovery in 1911, superconductivity has played an increasingly
important role in different fields especially for magnet technology. The
non-resistive characteristic of superconducting materials makes them very
attractive to achieve performances too demanding for conventional resistive
materials. Despite superconductivity being a common characteristic of many
metals, only a few of them are suitable for magnet applications requiring
a balance between the difficulty and operability of the system itself and
its overall cost.
In this talk, salient characteristics of superconductivity and its applications
will be discussed with particular focus on magnets for fusion energy.
In this application, large superconducting magnets will play a central
role in the success of the International Thermonuclear Experimental Reactor
(ITER) and for the future of fusion energy.
Cable-in-conduit conductors (CICC) will be used for the ITER magnets.
As a CICC is energized, electromagnetic forces accumulate across the conductor,
pressing strands transversely against one side of the conduit. Experimental methods
employed to study the mechanical characteristics of superconducting materials
will be presented and discussed.
Dan McCarron
IIT
Abstract
Recently performed study of intensity-dependent transverse coupling in the FNAL Booster
has yielded intensity-dependent horizontal and vertical tune slopes of opposite sign, quantitatively
and qualitatively different from those predicted both with simple image-charge analysis as well as
standard impedance formalism and the direct space-charge effect. In this talk we discuss the
measurements leading to these tune slopes. Recent publications have provided extensions to this
wakefield formalism to account for the presence noncircular vacuum chambers. We apply this
modification to the classic dipole wakefield due to the approximately rectangular geometry of the
magnets comprising much of the Booster lattice, wherein a substantial quadrupole component was
found to be responsible for the differing sign. Agreement to analytical results was obtained to within
25%. A study providing indirect measurement of the (incoherent) space-charge tune shift and tune
spread involving the extinction of the beam is also discussed in the context of this Booster model.
Presentation
Chandra Bhat
Fermilab
Abstract
Large Piwinski Angle scheme is one of the potential upgrade paths
to achieve luminosity L= 1035/cm2/sec at the LHC. This requires
reshaping the line charge distribution from nominal Gaussian shape
to flat distribution or increasing the crossing angle or both.
Here, I will talk about possible ways for creating flat bunches
and their stability, illustrated with simulations and recent beam
experiments in the LHC injector accelerators. As applied to the LHC,
we present simulation results for flat bunch creation and acceleration.
Address issues related to the intensity requirements and beam stability.
Presentation
Andrey Kabantsev
University of California at San Diego
Abstract
Diocotron instabilities are commonly observed when ions are mixed into dynamically stable pure electron plasmas.
Here, we demonstrate an exponential instability of lowest azimuthal modes with no apparent threshold and the
growth rate defined by the ion current or ionization rate/fraction. In essence, an ion traversing through an orbiting
electron column transfers its acquired canonical angular momentum to the column, thus giving a positive feedback
and driving the instability. This instability may have important implications for a variety of experiments that
continuously propel bunch of ions through magnetized electron plasmas, such as the ion beam space-charge
compensation experiments, or the double-well Penning traps to overlap cold positron and anti-proton clouds for
production of anti-hydrogen. Hence, various (both dynamical and dissipative) techniques to mitigate or/and suppress
the ion-induced instability have been also demonstrated in our experiments.
Presentation
Alexander Mikhailichenko
Cornell University
Abstract
We describe the method for long term acceleration of charged particles with the help of laser radiation.
This method uses many multi-cell microstructures aligned along the straight beam path. Each cell of
microstructure has an opening from one side. Focused laser radiation with appropriate wavelength
excites the cells through these openings. This excitation is going locally, in accordance with instant
position of accelerated micro-bunch of particles in the structure. For this purpose special devices
controllably sweep focused laser spot along the openings. This arrangement, what was called Travelling
Laser Focus (TLF), reduces the instant power required from the laser source and reduces illuminating
time for the every point on the structure. So the laser density does not exceed 0.3 J/cm2 for accelerating
rate ~10Gev/m. Illumination time for every point is <0.3ps while the time duration of laser pulse is ~0.1 nsec.
So 2 x 1 TeV collider will be ~2 x 100 m long and will require a laser flash 2x0.3 J total.
All components involved in the method described are using technology of present day. For energy
~1TeV the luminosity could reach 1035 with wall-plug power of few tens of kW only. Cost of such
installation could be as low as 100M$ (without cost of detector).
Alexei Smirnov
DULY Research, Inc.
Abstract
Two projects based on a normal-conducting, laser-driven photoinjector
and one project utilizing electron linac beam are considered. A
relatively compact, a few MeV photoinjector facility allows attaining
high peak power of coherent THz generation. It uses a short capillary
tube as a Cherenkov radiator driven by a conventional, ps- sub-ps RF
photoinjector employed in a new, overfocused mode of operation. A
polarized electron source based on RF photoinjector employs Andreev’s
structure with disks suspended in a strongly perforated, non-copper
tank. The structure combines enhanced vacuum conductivity and reduced
out-gassing rate at still substantial shunt impedance. Up to 50 MW has
been generated at 21 GHz using 7th harmonic of CTF II S-band linac
beam and ceramic microwave power extractor. Analytically simulated
and experimental waveforms are compared in a time-domain.
Presentation
Toru Ogitsu
KEK/J-PARC
Abstract
A superconducting magnet system for the J-PARC neutrino beam line was constructed.
The system consists of 14 doublet cryostats; each contains 2 combined function magnets (SCFM).
The SCFM uses two single layer left/right asymmetric coils that produce a dipole field of 2.6 T
and quadrupole of 19 T/m for 50GeV operation. The SCFMs had been developed by 2004,
mass-produced since 2005, and completed by summer 2008. The system has been installed
since Feb. 2008 till the end of 2008. A hardware commissioning as well as a beam commissioning
of the system was carried out in Jan. to May 2009. The presentation summarizes the magnet
development and system overview including cryogenics. The presentation also reports the
production, installation and commissioning status.
Holger Podlech
University of Frankfurt
Abstract
Intensive primary beams of protons and ions with high duty cycles up to
cw operation open new exciting perspectives in fundamental and applied
sciences. Depending on the specific application the driver accelerators
have to provide high beam power up to the multi-MW range. Examples are
linear accelerators for the production of radioactive ion beams, neutron
spallations sources, neutrino factories, nuclear waste transmutation of
long-lived radioactive fission products or neutron sources for the
material research for future fusion reactors. High duty cycles make
superconducting options attractive and under circumstances
technologically necessary.
Up to now there was a lack of efficient superconducting multi-cell
cavities for energies up to a few 10 MeV. The development of the
superconducting CH-structure at IAP (University of Frankfurt) closes
this gap. A 19 cell prototype cavity has been developed and tested
successfully with gradients of 7 MV/m. This talk covers the development
of this new type of cavity for room temperature and superconducting
operation. Additionally, a variety of projects like EUROTRANS, FAIR
proton linac, GSI cw linac for superheavy elements and FRANZ will be
presented.
Presentation
Jim Strait
FNAL
Abstract
The status of the LHC will be presented. This will include the repair of
sector 34, following last September's incident, the ongoing consolidation
work in the other sectors, and the progress with the new Quench Protection
System. The results of recent resistance measurements of the copper
stabilizers will be presented. The plans for recommissioning the the LHC
hardware systems will also be discussed. Finally the planning for the
start-up and the program for future operational consolidation work will
be detailed.
Peter McIntyre
Texas A&M
Abstract
Recent developments in accelerator physics and superconducting magnet
technology make it reasonable to extend proton-antiproton colliding beams
from the 2 TeV of the Tevatron to 100 TeV in the existing SSC tunnel. The
spectacular performance at the Tevatron of targetry, cooling and
accumulation of antiprotons, and detection and control of the tunes of
colliding bunches, provide a credible basis to project the potential for a
luminosity of 1E35 at collision energy of 100 TeV. Nb3Sn dipole
development has yielded field strength >16T, and 4-m-long coils using this
technology have been tested successfully. A conceptual design is presented
for a 100TeV collider in which a single 16 T magnet ring could be located in
the SSC tunnel. Issues from synchrotron radiation, electron cloud effect,
and beam separation are discussed.
Haruo Miyadera
FNAL
Abstract
Muon accelerators are proposed world wide for
future neutrino factories, muon colliders and other applications.
We carried out simulations on a large-acceptance muon linac that operates
using a novel “mixed buncher/acceleration mode”. Because of its large
acceptance, the linac can accept pions/muons from a production target
without any beam cooling and can accelerate them directly to high
energy. The linac has the following features: independent 805-MHz
cavity structure with 8-cm-radius aperture window; injection of a
broad range of pion/muon energies, 10-50 MeV, and acceleration to 200 MeV;
35 MV/m accelerating gradient. Further acceleration of the muon
beam can be done by extending the muon linear accelerator.
Presentation
Hyung Jin Kim
FNAL
Abstract
A beam-beam simulation code (BBSIMC) has been developed to study the
interaction between counter moving beams in colliders and its compensation:
a current carrying wire for compensation of long-range beam-beam interactions
and a low energy electron beam for compensation of head-on collisions. The wire
and electron beam are expected to improve intensity lifetime and luminosity of
the colliding beams by reducing the betatron tune spread and nonlinear effects
from the beam-beam interactions. We estimate the optimal parameters of the wire
and electron beam for compensating the beam-beam force by long-term simulations
of beam lifetime. These compensation mechanisms are intended to improve collider
performance after upgrades at RHIC and the LHC.
Presentation
Max Zolotorev
Lawrence Berkeley National Laboratory
Abstract
This tutorial covers the topic of electromagnetic radiation of charged
particles from a point of view different to the classical approach.
The complete symmetry between wave and particle optics is discussed
and an intuitive semi-classical approach is used for deriving the main
characteristics of all known radiation processes.
In the second part of the talk, it is also shown how the acceleration
of charged particles can be described as the result of the
interference between the external electromagnetic field and the
spontaneous radiation from the particles. Finally, the fluctuation
properties of the radiation from a bunch of particles are discussed.
Del Larson
University of Texas at Arlington
Abstract
A modular electron-cooled storage ring system for achieving particle-beam
fusion-based-energy is described. The system uses multiple electron-cooled,
overlapping storage rings to enable colliding-beam fusion. Particles are
continuously fed into the storage rings, and the electron cooling systems
continuously correct the ion beam trajectories, compensating for various
scattering events that occur in the system. This allows for large currents
to be built up in the ion storage rings. The rate of fusion reactions that
occur in the overlap regions between the storage rings can be increased by
focusing to enable power outputs of interest for fusion-based power reactors.
Present designs indicate that the system should be eventually able to produce
ten times more energy than is required to operate the device. The system
can be built with technology readily available today.
Marina Putti
CNR-INFM-LAMIA, Physics Department, University of Genova , Italy
ASC, National High Magnetic Field Laboratory, Florida State University, Tallahassee, USA
Abstract
The study of the effects of irradiation damage in superconducting materials is crucial for the twofold
aim of helping to understand the nature of superconductivity and of improving the superconducting
properties for applications. The main experiments performed on irradiated MgB2 are reviewed and
compared with similar experiments performed in the past on A15 superconductors [1]. The suppression
of the critical temperature (Tc) with disorder shows in both the kind of superconductors the existence of
an universal dependence of Tc on the residual resistivity. The defect structure and the effect of annealing
after irradiation are investigated. The behaviours of the upper critical fields, specific heat, resistivity and
magnetoresistivity upon irradiation are presented. The experiments of specific heat, tunneling and point
contact spectroscopies, which provide an evaluation of the energy gaps as a function of disorder, are summarized.
Finally, phenomenological models for the changes in the superconducting properties are discussed.
The overall experimental and theoretical evidences indicate that despite the same BCS coupling, A15s
and MgB2 get high Tc values by different features. A15 materials take advantage by the high DOS, whilst,
MgB2 presents a rather low DOS and the main ingredients are the high phonon energies and the presence
of the two bands. The behaviour of superconducting properties of MgB2 and A15s upon irradiation should
reflect these differences and primarily depend on the effect of disorder on these different ingredients.
Nevertheless, the comparison between the behaviour of damaged MgB2 and A15s has emphasized both
similarities and differences. The differences, as well as the important similarities, arising from the comparison
between the behaviour of irradiated MgB2 and A15 samples provide significant indications of an overall
understanding of radiation damage in superconducting materials.
[1] M.Putti, R.Vaglio and J.Rowell, Topycal Review Supercon. Sci. Thecnol. 21 043001 (2008)
Mauricio Lopes
FNAL
Abstract
This talk will present the results of designs studies of a high field section of a helical cooling channel (HCC) proposed for the 6D muon beam cooling. The discussion will cover the magnet aperture limitations, tunability of field components and field correction, superconductor choice and magnet operation margin.
Eliana Gianfelice-Wendt
FNAL
Abstract
The success of Tevatron Run II is based on advances in the accelerator
physics, as well as, on the excellence and advances in engineering,
instrumentation and machine operation. In this series of lectures we
would like to review the main advances in Accelerator physics which
contributed to the luminosity growth and/or improvement of the Tevatron
complex operations. The lectures are aimed for the Run II participants
who would like to deepen their understanding of the accelerator physics.
The level of the presented material corresponds to the advanced course
of accelerator physics but at the same time we would like to present
material so that it could be understandable for less prepared listeners.
The outline for Lecture 2 is:
Presentation
Valeri Lebedev
FNAL
Abstract
The success of Tevatron Run II is based on advances in the accelerator
physics, as well as, on the excellence and advances in engineering,
instrumentation and machine operation. In this series of lectures we
would like to review the main advances in Accelerator physics which
contributed to the luminosity growth and/or improvement of the Tevatron
complex operations. The lectures are aimed for the Run II participants
who would like to deepen their understanding of the accelerator physics.
The level of the presented material corresponds to the advanced course
of accelerator physics but at the same time we would like to present
material so that it could be understandable for less prepared listeners.
The outline for Lecture I is:
Valeri Lebedev
FNAL
Abstract
The success of Tevatron Run II is based on advances in the accelerator
physics, as well as, on the excellence and advances in engineering,
instrumentation and machine operation. In this series of lectures we
would like to review the main advances in Accelerator physics which
contributed to the luminosity growth and/or improvement of the Tevatron
complex operations. The lectures are aimed for the Run II participants
who would like to deepen their understanding of the accelerator physics.
The level of the presented material corresponds to the advanced course
of accelerator physics but at the same time we would like to present
material so that it could be understandable for less prepared listeners.
The outline for Lecture I is:
Alvin Tollestrup
FNAL
Abstract
The physics of the processes that can lead to breakdown of the cavity and to the destruction of the cavity Q will be discussed.
Seunghwan Shin
FNAL
Abstract
Realization of a precise beam handling is strongly required in future accelerators such as linear colliders (LC) and X-ray free electron lasers (XFEL). The key component to realize a precise beam handling is a high resolution beam position monitor. An RF cavity type beam position monitor (Cavity BPM) is a candidate to measure the beam position in nano-meter resolution. In this presentation, activities of cavity BPM R&D at KNU (Kyungpook National university) as well as Fermilab will be described.
Hitoshi Hayano
KEK
Abstract
New Electro-chemical Polishing facility (EP facility) in STF was commissioned in 2008 by the collaboration of FNAL cavity. Being connected to this commission, we started the basic R&D of EP treated niobium surface inside of the cavity. The purpose of the R&D is to aim high gradient, 35MV/m, the target of ILC. To get rid of try and error type R&D, we are seeking the method to understand what is going on the real cavity inside, such as optical inspection of heated region, application of surface analysis tools to understand what is the residuals after EP treatment. This is the introduction of our 1-year R&D effort, still in the beginning stage, such as; XPS, SEM, EDX analysis of EP treated Nb surface, sulfur removal experiment, optical inspection results, and tool developments like inspection camera, sponge-wipe mechanics, and local grinding mechanics.
Aida Todri
University of California at Santa Barbara
Abstract
In this talk, we present an overview of the design and challenges of power network distributions on integrated circuits (ICs). We provide a brief perspective on the development of ICs and introduce the problem of power distribution. As processing technologies shrink to deep submicron regime, more transistors are packed on the same area and at the same time leakage currents become non-negligible causing power consumption and management to become an essential problem. Leakage current reduction is achieved by shutting power off to the idle circuits on the chip referred to as power gating. However, implementation of power gating can impose reliability issues on the power network. We describe the implications and electromigration mechanism that can occur due to power gating. We additionally, discuss the signal and power integrity of power networks and their dependencies to decoupling capacitance efficiency and workload’s frequency for multi-cores systems.
John Consiglio
The Cooper Union
Abstract
The Environmental Protection Agency (EPA) mandates the FTP-75 emissions certification test which is used to rate the emissions of cars and light trucks sold in the USA. The test specifies a driving cycle that is representative of real world automobile usage. The driving cycle loading schedule, however, is derived from simplified 'road load' coefficients and may not match the loadings present in real world driving situations. A hardware-in-the-loop simulation can be used that will more accurately predict the loads imparted on the powertrain. Design details of the hardware-in-the-loop powertrain testing will be presented along with results from several driving cycles.
Sandor Feher
FNAL
Abstract
Bringing up the world largest superconducting magnet system was a great challenge. I summarize this tremendous effort leading to successfully circulating beams on September 11th 2008. I also pay special attention to interesting features discovered in this process including the September 19th event.
Presentation
Olivier Napoly
CEA-Saclay
Abstract
The assembly of the 3 pre-series and 100 series superconducting linac modules is part of the In-Kind contribution of France to the XFEL project. This operation is planned for the years 2011-2012 to take place on the Saclay site in a new infrastructure operated by an industrial company under the responsibility of the CEA/Irfu department. It will include the assembly of the 103 cavity strings in a new 112 m2 ISO4 clean room and the module assembly in a set of 3 adjacent halls. The status of this project as well as the ongoing preparation work is described.
Laurie Waters
LANL
Abstract
High power accelerators and spallation targets have a history that goes back to the early 1950's. Accelerator-driven neutron spallation sources have operated for years, but broader forays into more industrial applications traditionally handled by reactors started to receive serious funding in the 1990's with the Accelerator Production of Tritium (APT) project. Research for this device, which was never built, led to a series of other ideas, such as Accelerator Transmutation of Waste (ATW), Advanced Accelerator Applications (AAA), and the Advanced Fuel Cycle Initiative (AFCI). This talk will review these programs, and summarize our current impressions of how the concept is viewed by potential funding agencies today.
Hans Weise
DESY
Abstract
With main emphasis on the XFEL's cold linac a summary of the work done by the Accelerator Consortium will be given. Final prototyping of components and the preparation of large call for tenders are the main issues in 2009. The civil construction was started. Most of the possible in-kind contributions are identified.
Dileep K. Bhogadi
University of Kansas / Korea University of Technology
Abstract
Currently, cell manipulations for Intra Cyto Plasmatic Cell Injection (ICSI) are
performed manually. These highly precise operations require high-skilled professional operators. However,
the success and survival rate of the cells is very low due to the great sensitivity of cells. Moreover, while
manipulating, the operator cannot feel any interaction with the cells because of their negligible mass.
Conventional cell manipulation does not have the ability to provide force feedback to an operator.
Therefore all the operations are based on the visual information provided by the high-precision microscope.
In addition, vibrations of human’s hand can affect the quality of micromanipuation tasks. Therefore, there
exists a need to design a robotic arm for cell injection process and to incorporate haptic force feedback
along with visual feedback into a cell injection system, with the capability of representing contact forces
in the range of µN-mN. In order to know the contact forces experiencing by the cell membrane, a good understanding
of the biological cell dynamics throughout the cell injection process is necessary.
In this presentation, I will give a brief introduction about the design, simulation and development of a novel
tele-robotic system. A visual feedback and haptic force feedback techniques for cell injection process will also be
presented and discussed. The goals of this proposed effort were to overcome problems related to manual operations
for micro-cell injection applications. This research work will have immediate applications in the biological cell injections,
drug delivery applications and various medical applications.
Nikhil Jethava
NIST
Abstract
Superconducting Transition Edge Sensors (TES) simple and robust incoherent continuum detectors, which nevertheless can reach sensitivities close to the fundamental noise limit. TES offers various advantages over the traditional semiconducting detector; it is faster, more sensitive, has a higher dynamic range, allows complete microlithographic fabrication and can be multiplexed with Superconducting Quantum Interference Devices (SQUIDs). The low noise SQUID amplifiers operate at bolometer temperatures and have very low power dissipation. The fabrication of TES with integrated SQUIDs and the multiplexing electronics will allow the production of bolometer arrays with several hundred or more pixels. TESs can be used as bolometer (total power detection) and as micro-calorimeter (energy measurement). I will discuss two of its applications: 1) detectors for astronomy in millimeter and sub-millimeter wavelength regime, and 2) micro-calorimeters for nuclear line forensics. I will present a bolometer system, which is commissioned at an astronomical telescope site, and a micro-calorimeter system that successfully measured the complicated plutonium isotopic spectra.
James T. Volk
FNAL
Abstract
Understanding slow and fast ground motion is important for the successful operation and design for present and future colliders. Since 2000 there have been several studies of ground motion at Fermilab. Several different types of hydro static water levels have been used to study slow ground motion (less than 1 hertz) seismometers have been used for fast (greater than 1 hertz) motions. Data have been taken at the surface and at locations 100 meters below the surface. Data and results of both slow and fast ground motion will be discussed in particular the effects of natural and cultural sources of motion.
Slava Danilov
Oak Ridge National Lab
Outline
SNS physics and technology, related to the following issues: Ring instabilities, space charge, laser stripping. Sequence of developments as SNS ring intensity increases. Nonlinear accelerator lattices with regular motion and large tune spread to kill instabilities and mitigate space charge effects.
Presentation
Alexey Burov
FNAL
Abstract
Head-tail modes are described when the space charge tune shift significantly exceeds the synchrotron tune. Spatial shape of the modes, their frequencies, coherent growth rates and Landau damping rates are found.
Talks
in 2008
Robyn Madrak
FNAL
Abstract
We will give updates on the fast chopper and the 325 MHz vector modulators for HINS.
A fast chopper capable of kicking single 2.5 MeV H- bunches spaced at 325 MHz, at rates greater than 50 MHz is needed for the Fermilab High Intensity Neutrino Source (HINS). Four 1.2 kV fast pulsers, designed and manufactured by Kentech Instruments Ltd., will drive a 0.5 m long meander made from a copper plated ceramic composite. Test results showing pulses from the first 1.2 kV pulser and meander results will be presented.
One of the goals of the low energy 60 MeV section of the HINS H- linac is to demonstrate that a total of ~40 RF cavities can be powered by a single 2.5 MW, 325 MHz klystron. This requires individual vector modulators at the input of each RF cavity to independently adjust the amplitude and phase of the RF input signal during the 3.5 ms RF pulse. Two versions of vector modulators have been developed; a 500 kW device for the radiofrequency quadrupole (RFQ) and a 75 kW modulator for the RF cavities. High power tests showing the vector modulator phase and amplitude responses will be presented.
Stephen Molloy
SLAC
Abstract
The
radio-frequency cavities used to accelerate beams of charged
particles are known to support many different modes of electromagnetic
oscillation in addition to the fundamental, accelerating, mode. It is
well known that these parasitic, or Higher Order Modes (HOMs),
may
strongly degrade the quality of the beam, and limit the performance of
the accelerator, so they are normally thought of as something that
should be avoided and suppressed by suitable design of the machine.
This talk discusses work done to demonstrate the positive contribution
these modes can make to the performance of the machine by providing
multiple, high resolution, beam trajectory measurements, as well as
information on the alignment of the accelerating cavities, and the phase
stability of the acceleration system.
A brief overview of the physics of
description of the experiment performed at the FLASH light source in
DESY,
Presentation
James T. Volk
Fermilab
Abstract
Since 1995 research and development of permanent magnets has been done at Fermilab. The most important effort was the building of the Recycler ring for storage of anti protons. This is a 3.6 km in circumference ring made with 486 magnets all using strontium ferrite permanent magnets. Up to 450 x 1010 anti protons are stored in this ring. Basic design parameters and assembly techniques used for the recycler will be discussed. In addition work done on adjustable quadrupole magnets will be discussed. These are high field (greater than 100 Tesla per meter gradient) quadrupoles with an adjustable gradient of 20% of full field.
Thomas Hott
DESY
Abstract
The XFEL project status and the special role XFEL plays for ILC are described.
Henryk Piekarz
Fermilab
Abstract
The arrangement of a duoplasmatron proton source with its low energy beam transport (LEBT) system for HINS front-end first tests is described, and proton beam results as well as some operational issues are presented. Implication of experience gained with duoplasmatron proton source for a possibility of a Cs-free H-minus source for the future HINS is discussed.
Presentation
Valeri Lebedev, Dave McGinnis and
Sergei Nagaitsev
Fermilab
Abstract
The future of accelerator-based high energy physics at Fermilab relies on
the construction of a high intensity proton source. Most proton sources
consist of a linac feeding a rapid cycling
synchrotron. The performance of
these sources is a compromise between the space-charge tune shift
limitations at injection into the synchrotron and the high cost of RF power in
the linac. The advent of superconducting RF holds the
promise of making a
high power linac more affordable. By blending the
performance of a
superconducting linac with the energy range of a
synchrotron, a very
flexible and cost-effective proton source could be realized. This proton
source could be built in stages. The construction of a project in well
defined stages in which at the end of every stage a substantial increase in
performance is obtained is very attractive in these times of tight budgets.
This talk will examine the parameters and staging of such a source.
Paul Derwent
Fermilab
Abstract
We have developed an initial configuration for the Steering group path to the
intensity frontier. It consists of an 8 GeV
superconducting linac, the Recycler, and the Main
Injector. I will describe the configuration, the reasoning, and the first
thoughts on the plan.
Dariusz Bocian
CERN
Abstract
A quench, transition of a conductor from the superconducting to the normal
conducting state, occurs irreversibly in accelerator magnets if one of the
three parameters: temperature, magnetic field or current density, exceeds a
critical value. Energy deposited in the superconductor by the particles lost
from the beams, provoke quenches detrimental for the accelerator operation.
A Network Model is used to study of the thermodynamic behaviour
of the LHC magnets. The results of the heat flow simulation in the magnets with
the network model were validated with measurements performed in the CERN magnet
test facility. A steady state heat flow was introduced in the coil by using
both the quench heaters implemented in the LHC magnets and a dedicated internal
heating apparatus installed inside cold bore. The heat loads from these heat
sources needed to initiate quenches as a function of the coil current are
calculated from the Network Model and compared to the settings leading to
quench occurence.
Presentation
Jim Norem
Argonne National Laboratory
Abstract
Recent developments in modeling high gradient behavior in rf
structures, and new techniques in controlling the chemistry and morphology of
surfaces seem to open the possibility of operating rf
systems at higher gradients than are presently achieved. The talk will review
new developments in modeling and new ideas on surfaces compatible with high
gradients.
Marco Danuso
Sant'Anna School (Pisa) and Fermilab
Abstract
Future upgrades of machines like the LHC at CERN require pushing accelerator
magnets beyond 10 T. Larger magnet sizes and more performing superconductors
introduce additional challenges. This work improves existing analytical models
of the magnetic field and stress of dipole and quadrupole
sector windings, addressing how far the engineering of High Field Magnets can
be pushed. Problems and limitations of Nb3Sn magnets are identified by
correlating the field intensity and the loss of field quality to the magnetic
and mechanical properties of the material.
Alan A. Hahn
Fermilab
Abstract
The complexity of instrumentation sometimes requires data analysis to be done
before the result is presented to the control room. This tutorial reviews some
of the theoretical assumptions underlying the more popular forms of data
analysis and presents simple examples to illuminate the advantages and hazards
of different techniques.
Tom Peterson
Fermilab
Abstract
Warm people (as opposed to cryogenic experts) whose project includes cryogenics
will find it useful to have some familiarity with a few of the basic principles
and common standard practices in cryogenics. These include methods of
refrigeration, heat transport modes, piping stability, and safety and
compliance issues. Common cryogenic system components, such as lambda plugs, Kautzky valves, bayonets, and wet engines are described,
and some mysteries of cryogenics at Fermilab are explained.
Manoel Conde
Argonne National Laboratory
Abstract
The Argonne Wakefield Accelerator Facility (AWA) is dedicated to the study of
electron beam physics and the development of accelerating structures based on
electron beam driven wakefields. In order to carry
out these studies, the facility employs a photocathode RF gun capable of
generating electron beams with high bunch charges (up to 100 nC) and short bunch lengths. This high intensity beam is
used to excite wakefields in the structures under
investigation. The wakefield structures presently
under development are dielectric loaded cylindrical waveguides with operating
frequencies of 8 -15 GHz, in which gradients of 100 MV/m have been reached.
Similar structures have also been used as RF power sources, driven by single
electron bunches or bunch trains of up to 16 bunches. Other important
experiments, at different RF frequencies and using planar or cylindrical
geometries, have been carried out at various other facilities. A number of new
experiments are planned in the near future to explore the capabilities of this
class of structures. This presentation will provide an up-to-date survey of the
activities in this area of research.
Special time/location: 11 am in Curia II
Alexey A. Poklonskiy
Michigan State University
Abstract
Many problems from the fields of accelerator physics and beam theory can be formulated
as optimization problems and thus can benefit from modern optimization
techniques. However, the use of such techniques in these fields is so far
rather limited. Relatively new and actively developed Evolutionary Algorithms (EAs) for optimization possess many attractive features such
as: ease of implementation, modest requirements on the objective function, good
tolerance to noise, robustness and the ability to efficiently perform a global
search. These make them the tool of choice for many design and optimization
problems. We present several different problems of accelerator design and
demonstrate how they can be treated by EAs.
Vsevolod (Seva) Kamerdzhiev
Randy Thurman-Keup
Manfred Wendt
Fermilab
Abstract
Highlights from the Beam Instrumentation Workshop (BIW08) will be shown.
Mike Syphers, FNAL
Janet Conrad, Columbia University
Abstract
A proposal for a new Fermilab neutrino experiment, NuSOnG,
is discussed. The experiment utilizes the 800 GeV
fixed target capabilities of the Tevatron and the
beam intensities commensurate with the Main Injector to make precision
electro-weak measurements at the Terascale. This talk
briefly describes the experiment and also discusses the issues with
resurrecting fixed target operation of the superconducting synchrotron.
Kirk McDonald
Princeton University
Abstract
The MERIT experiment was designed as a proof-of-principle test of a target system
based on a free mercury jet inside a 15-T solenoid that is capable of
sustaining proton beam powers of up to 4MW. The experiment was run at CERN in
the fall of 2007. This talk describes the background of this experiment,
the results of the tests and their implications for new facilities
including a muon collider.
Steve Holmes
FNAL
Abstract
Project X represents a world-leading multi-MW proton facility at Fermilab, with
strong technology connections to linear collider and muon
based facilities. This talk will describe the concept and performance goals for
Project X, the proposed R&D program, and its role in possible long term
evolution of the Fermilab accelerator complex.
Mike Syphers
FNAL
Abstract
Recent record-setting performance of the Fermilab Tevatron
is the culmination of a long series of efforts to optimize the many parameters
that go into generating particle collisions for the colliding beams
experiments. The instantaneous luminosity is determined by the number of
particles in each beam, the physical extent of the beams at the collision
point, and the bunch collision frequency. Meanwhile, the integrated
luminosity also depends upon the rate at which particles are lost due to
collisions or other means, as well as the rate at which the initial store
luminosity can be restored after the end -- intentional or otherwise -- of the
previous store. Here we take an analytical approach in an attempt to
illustrate the most fundamental aspects of integrating luminosity in the Tevatron. The essential features, including recent
values of the weekly integrated luminosity, can be understood in a transparent
way from basic operational parameters such as antiproton accumulation rate and
beam emittance growth rate in the Tevatron.
Operational considerations as the Tevatron
operates at or near the ``beam-beam limit'' are also discussed.
Alexander Zlobin
FNAL
Abstract
Nb3Sn accelerator magnets advance machine operation fields above 10
T and increase operation margins. Fermilab is working on the development of Nb3Sn
accelerator magnet technology in collaboration with BNL and LBNL. These efforts
are being coordinated in the framework of US-LHC Accelerator Research Program
(LARP). A first step of this R&D includes the demonstration of the main
magnet parameters (maximum field, quench performance, field quality, etc.) and
their reproducibility using series of short models. Then technology scale up is
performed using long coils. The status and main results of the Nb3Sn
accelerator magnet development at Fermilab (both LARP and core program) will be
presented and discussed.
The primary goal of this work is the development of large aperture
high-performance Nb3Sn quadrupoles for the
LHC luminosity upgrade. At present the upgrade is planned in two phases with
the target luminosity for Phase I of ~2.5∙1034 cm-2s-1
and up to 1035 cm-2s-1 for Phase II. In Phase
I the baseline 70-mm NbTi low-beta quadrupoles will be replaced with larger aperture NbTi magnets and in Phase II with higher performance Nb3Sn
magnets. Recent progress in Nb3Sn accelerator magnet R&D
suggests the possibility of using Nb3Sn quadrupoles
in the Phase I upgrade, improving the LHC performance and providing an early
demonstration of Nb3Sn magnet technology in a real accelerator
environment. Possible hybrid optics layouts for Phase I upgrade with both NbTi and Nb3Sn quadrupoles,
magnet parameters and issues related to using Nb3Sn quadrupoles as well as possible transition scenarios to
Phase II will be also presented and briefly discussed.
Yoshihisa Iwashita
Kyoto University
Abstract
High-resolution surface inspection camera could show ever
undiscovered defects where T-mapping and/or passband
mode measurements suggested abnormalities.
The system will be explained together with recent observations.
Our recent activities will be presented briefly as an introduction.
Jim Patrick, Brian Hendricks, and Charlie Briegel
Fermilab
Abstract
With Fermilab's thrust for new accelerator
initiatives, the control system for the accelerator complex will have to be
functional well past 2010. It will need to evolve to meet the new demands and
keep up with technology. The Fermilab Controls Department has initiated this
evolution by writing the requirements for the future control system. In this
talk, we will explain the motivation and the requirements process. We will
present some of the ideas for the new controls, and a plan for the next steps.
Emanuela Barzi
Fermilab
Abstract
An ongoing effort at FNAL and elsewhere focuses on the endeavor of making state-of-the-art magnets for present and future accelerators. The High Field Magnet and LARP Programs need high field dipoles and quadrupoles, and Muon Collider R&D requires very high field solenoids. In the last 10 years, within a Superconductor R&D program at TD, a large infrastructure, including two short sample test facilities, a cabling machine to fabricate Rutherford-type cables, and furnaces for heat treatment, was built upon this need with the mission to serve as an interface between materials and magnets. This superconductor R&D program encompasses the study of LTS beyond NbTi, and HTS materials. As a leading center for conductor technology, for LTS like brittle Nb3Sn and Nb3Al, our research and scientific studies have focused on the process of cable development because of the many different phenomena occurring in the round strand that can deeply modify their performance in magnets. For instance the Nb3Sn dipole magnet performance can be gravely compromised by flux jump instabilities, which we found to be inherent to high-Jc Nb3Sn conductors. For HTS solenoid applications, our program aims at monitoring state-of-the-art conductors, solving present challenges of tapes and wires, and developing appropriate cable and coil technologies. These studies, which are broad in spectrum and scope, will help us develop a most enriching vision for the future.
Raymond Fliller III
Fermilab
Abstract
The A0 Photoinjector is a 16MeV electron linac used for Accelerator R&D. It consists of a 1.3 GHz copper RF gun and a TESLA type superconducting cavity. Through its history, multiple beam physics experiments have taken place. Most recently a transverse to longitudinal emittance exchange beamline has been installed. This beamline uses a copper 3.9 GHz deflecting mode or crab cavity between two doglegs to affect the exchange. Data taking for this experiment is underway. Various mechanisms may dilute this exchange or effect the measurement. In this talk we will discuss the theory and initial data taking for the emittance exchange, and the physics that can dilute it, such as Coherent Synchrotron Radiation. We will also discuss other R&D activities that have applications to other machines which may be built at Fermilab such as the ILCTA-NML.
Valeri Lebedev
Fermilab
Abstract
Recent stacking rate records are the result of many improvements in Antiproton Source. Details of the work carried out during last 1.5 year and the accelerator physics behind them will be discussed.
Giulio Stancari
INFN Ferrara
Abstract
Francium is one of the best candidates for measurements of atomic parity violation and for the search of permanent electric dipole moments. These fundamental measurements rely on precision studies in atomic spectroscopy and on the development of magneto-optical traps. A radioactive francium beam facility has been commissioned at INFN's national laboratories in Legnaro, Italy. The physics of francium production and trapping will be discussed, together with some of the technical challenges involved and a summary of recent results. Several options are being considered for future upgrades of this unique facility, including the new concept of a recirculating-beam ion source, which combines ionization cooling of a stored primary beam with a thin internal production target.
Riccardo de Maria
CERN
Abstract
The seminar is focused on beam optics design studies on interaction region layouts for a LHC luminosity upgrade. Two layouts options "dipole first" and "quadrupole first" are analyzed and compared.
Ralph Assman
CERN
Abstract
The Large Hadron Collider at CERN will store and collide proton and ion beams with unprecedented intensities and destructive potential. Small fractions of the beam can be lost during operation. These losses require highly efficient and robust collimation such that the accelerator is protected against quenches and damage. The loss-induced challenges for the LHC are reviewed and the collimation system is described. Special focus is put on future research requirements for collimation upgrades and on opportunities for inter-laboratory collaborations.
S.Yu. Kazakov
KEK
Abstract
The general principles, design solutions and performance of the high-power RF sources the author worked on are considered for both “warm” and SC versions of a linear collider. The problems of high–power RF windows for accelerator applications, as well as the several types of the new windows the author invented, are discussed. The power multiplication schemes and examples of the some exotic high RF power components the author developed for these schemes are described, namely mode launchers, mode converters, power dividers, phase shifters, etc. The design and test results of a new, inexpensive and simple sectioned high-power input coupler for the SC collider option, developed by the author for ILC SC cavities, are presented. Finally, the results of the work on an ultra-fast electrically-controlled L-band ferroelectric tuner, which allows fast coupling and phase control of the SC acceleration cavities, are presented.
November 14, 2007 (special
seminar!)
Chris Tschalaer, Bill Franklin, Aleem Siddiqui and Fuhua Wang
MIT/Bates
Abstract
The talk will be split into four parts:
OSC formalism (Chris Tschalaer)
Superfast optical parametric amplifier (30 ps) allows
small-angle, longitudinally "rigid" particle bypass. Longitudinal
coherence is
achieved with much looser tolerances for bypass magnets. Amplifier output power
of 20 W available shortly achieves 2 hour
cooling time.
Bates OSC experiment (Bill Franklin)
First ever OSC demonstration with 300 MeV Bates
electron ring. Short cooling times (sec) allow "real-time"
tuning. Development of OSC diagnostics and beam control.
Optical parametric amplifiers for Bates and Tevatron
(Aleem Siddiqui)
Development of amplifiers with 20-100 W average output power.
Technical concept for Tevatron cooling (Fuhua Wang)
Undulator and bypass in a Tevatron
straight section. Simultaneous cooling of protons and antiprotons.
Concept for cooling radially distributed proton bunches.
Presentation
Angelo Dragone
Brookhaven National Laboratory
Abstract
During the last ten years, the development of microelectronics for radiation detector applications has faced a big impulse. Starting from pure analog ASICs integrating a few channels designed according to the classical front end schemes, more and more functionalities have been added. Realtime processing of the signals, at first in the analog domain and lately in the digital one, arbitration and multiplexing schemes have been introduced to reduce the number of interconnections and the amount of information to transfer to the data acquisition systems. During this talk a few examples of architectures developed at Brookhaven National Lab during the last four years will be presented with the aim to give an overview of the groups' and personal expertise.
Mike Tartaglia
Fermilab
Abstract
The International Linear Collider reference design requires over 13000 magnets, of approximately 135 styles, which must operate with very high reliability. The Fermilab Main Injector represents a modern machine with many conventional magnet styles, each of significant quantity, that has now accumulated many hundreds of magnet-years of operation. We review here the performance of the magnets built for this machine, assess their reliability and categorize the failure modes, and discuss implications for reliability of similar magnet styles expected to be used at the ILC.
Linda Klamp Spentzouris
Illinois Institute of Technology
Abstract
IIT is one of several universities in the Chicago area with faculty and graduate student research in the area of accelerator physics. The present status of graduate student projects on the topics of metamaterial-loaded waveguides and Booster space charge studies will be reviewed. The metamaterial-loaded waveguide work was motivated by the possibility of customizing the dispersion function of the loaded waveguide, with the potential of suppressing higher-order modes. Calculational work and preliminary experimental data will be discussed. A Booster space charge coupling study will be presented, along with a discussion of status and future plans.
Presentation
October 02, 2007
Sergey Strokov
University of Hiroshima
Abstract
The crystals are good candidates to use them in a beam extraction device at J-PARC and in a beam collimation device at ILC. The results of the experiments on deflection of electrons and protons performed in Japan will be presented. The prospect of the future channeling experiments in Japan will be discussed as well.
Presentation
September 18, 2007
Abstract
Breakdown is a limiting factor in rf devices from cavities for particle accelerators to waveguides for tokomak heating and rf delivery. Modeling breakdown is challenging because of the need to handle the generation and behavior of impurities. Processes such as sputtering, charge exchange, multiple ionization, and radiation are all important, but are not typically handled in traditional breakdown codes. I will discuss how we are addressing the challenges above in two particle-in-cell codes: OOPIC Pro and VORPAL.
Presentation
Studies of Charged Particle Beam Dynamics on
the Paul Trap Simulator Experiment (PTSX)
Moses Chung
Plasma Physics Laboratory, Princeton
University
Abstract
At the high beam intensities envisioned in present- and next-generation accelerators, a fundamental understanding of the influence of collective processes and self-field effects on beam transport and stability properties must be developed. To address these issues experimentally, the Paul Trap Simulator Experiments (PTSX) device was proposed and constructed at the Princeton Plasma Physics Laboratory (PPPL). The PTSX device is a cylindrical Paul trap that simulates a long, thin charged-particle bunch coasting through a kilometers-long alternating-gradient (AG) magnetic transport system by putting the physicist in the beam’s frame-of-reference. The transverse dynamics of particles in both systems are described by similar equations, including all nonlinear space-charge effects. In this talk, descriptions of the PTSX device and diagnostics are given, related theoretical backgrounds are summarized, and experimental results on beam mismatch, transverse beam compression, random noise effects, and collective modes are presented. Experimental results are also compared with WARP particle-in-cell (PIC) simulations.
Presentation
August 30, 2007
Zachary Conway
ANL
Abstract
Multi-spoke-loaded
superconducting niobium accelerator cavities are being developed for heavy-ion
accelerators with application to both cw and pulsed
ion linacs necessary for several proposed accelerator
facilities. Multi-spoke cavities have been developed to accelerate ions
from protons through uranium over the velocity range spanning 0.35 < beta
< 0.75. Recent results of cold tests, focusing on the mechanical
properties and the dramatically-improved RF performance will be presented.
Presentation
Lance Cooley
FNAL
Abstract
Superconducting
materials for RF linear accelerators have attracted renewed attention, thanks
in large part to present and former Fermilab personnel who have organized and
hosted a series of workshops in recent years. I will review the latest of
these, held this past May, which marks an important expansion from a regional
meeting into a truly national meeting with >70 attendees. The workshop
focused on topics such as theoretical limits to superconducting RF,
understanding the basic materials science of niobium, surface characterization
techniques, other superconducting materials, alternative processing strategies,
and niobium processing and cavity fabrication. I will discuss highlights from
each of these areas, and describe their potential impact on the ILC. In
addition, since niobium is an enabling technology for very high gradient
accelerators, I will explore implications of workshop presentations for SRF
science in general, including the possibility for generating gradients beyond
the limits of niobium. An important by-product of the workshop expansion has
been recognition of basic work by funding agencies, and I will discuss briefly
my opinion about future materials research.
Fanglei Lin
Indiana University
Abstract
Two partial helical dipole snakes have been employed
successfully to overcome all imperfection and intrinsic spin resonances in the
AGS provided that the vertical betatron tunes were
maintained in the spin tune gap near the integer 9. However, the measured
maximum 65% polarization at the AGS extraction energy shows still about 20%
polarization loss comparing with the injected 82%. Except for the horizontal
intrinsic resonances introduced by the two partial snakes, there were also
polarization drop due to the residual vertical intrinsic resonances, partial
snake resonances and orbit distortion where the vertical betatron
tune beyonds 8.99. This talk presents the
investigation of polarization of proton beam in the AGS, including the
experimental results and simulations. Possible cures of the remaining beam
polarization are also discussed.
Presentation
Resonant multi-turn extraction project:
principle and experiments at the CERN Proton Synchrotron
Massimo Giovannozzi
CERN
Abstract
Recently a novel approach to perform multi-turn extraction was proposed based on beam splitting in the transverse phase space by means of trapping inside stable islands. In addition to numerical simulations, aimed at assessing the feasibility of the proposed technique, an experimental campaign was launched since the year 2002 at the CERN Proton Synchrotron. During the year 2004 run, a high-intensity single-bunch beam was successfully split and the generated beamlets separated without any measurable losses. The underlying principle will be presented and discussed in details as well as generalizations of the method to multi-turn injection and the latest experimental results.
Presentation
TMCI REVEALED BY
FREQUENCY ANALYSIS
OF HEADTAIL TRACKING DATA USING SUSSIX
E. Métral (work with G. Rumolo, B. Salvant and R. Tomás)
CERN,
Abstract
Since 2003, high-intensity single-bunch proton beams with low longitudinal emittance have been affected by heavy losses after less than one synchrotron period in the CERN SPS. Measurements of the turn-by-turn evolution of the instability have been compared with HEADTAIL simulations, exhibiting a remarkly good agreement. In both cases, a travelling-wave pattern propagating along the bunch was clearly identified, which was believed to be the signature of a Transverse Mode Coupling Instability. Recently, using SUSSIX to analyze tracking data from HEADTAIL via frequency analysis, previous predictions from MOSES, which computes the coherent bunched-beam modes, have been confirmed. In particular, using the SPS beam parameters, a coupling between the azimuthal modes -2 and -3 is taking place. This regime of TMCI is more intricate than the one observed in the past with leptons as the proton bunches are much longer. The next step will be to perform measurements in the SPS to verify this prediction.
Presentation
June 21, 2007
Longitudinal Emittance
Control in the CERN PS
Heiko Damerau
CERN
Abstract
Thorough
control of the longitudinal emittance is essential
for the
acceleration of high intensity beams in the CERN PS.
Therefore, the longitudinal emittance must be
increased in a controlled
way to avoid beam losses due to instabilities. The higher harmonic 200
MHz RF system (six cavities) used for these blow-ups has to generate a
total RF voltage which, for the most demanding blow-up, is comparable to
the voltage of the principal RF system. After an introduction to the
CERN PS Complex and the RF manipulations needed to produce beams for the
LHC and for the anti-proton decelerator (AD), measurements and
simulations of the longitudinal blow-up are presented.
Presentation
Status of the LHC
Inner Triplets
Jim Kerby
Fermilab
Abstract
The status of the LHC inner triplets will be described.
Parametric studies
for a phase-one LHC upgrade based on Nb-Ti
Ezio Todesco
CERN
Abstract
Several options for a luminosity upgrade based on Nb-Ti
"long" quadrupoles have been studied in the
past years. In this seminar we present a parametric study aiming at finding the
relations between the triplet length, its aperture, and the minimum beta
functions that can be achieved in the IP using quadrupoles
built with the LHC main dipole cable. We carry out the electromagnetic design
for apertures ranging from 100 to 140 mm, extending the results of previous
work, and using the critical currents as measured in the LHC cable production.
Issues related to forces and protection in these large aperture magnets are
presented.
We then consider the hypothesis of a phase-one upgrade, where the detectors are
not modified, and therefore the maximal goal is to double the luminosity or to
allow a recovery from non-nominal parameters using stronger focusing. We show
that a solution with 130 mm aperture and 34 m long triplet (i.e., 10 m longer
than nominal) would allow reaching a beta function in the IP of 25 cm. This
would also leave some clearance for removing the limitations in beam intensity
due to the impedance of collimators. Finally, we show that this additional
clearance also allows improvement of the field quality, thus reducing the nonlinearities
arising from the large beta functions.
Accelerator
Division
Roger Dixon
Fermilab
Abstract
Presentation
Craig Drennan
Fermilab
Abstract
To
better control the beam position, tune, and chromaticity in the Fermilab Booster
synchrotron, a new package of six corrector elements has been designed,
incorporating both normal and skew orientations of dipole, quadrupole,
and sextupole magnets. The devices are under
construction and will be installed in 48 locations in the Booster
accelerator. Each of these 288 corrector magnets will be individually
powered. Each of the magnets will be individually controlled using
operator programmed current ramps designed specifically for the each type of
Booster acceleration cycle. This presentation will provide an overview of
the corrector magnet installation in the accelerator enclosure, power and
sensor interconnections, specifications for the switch-mode power supplies,
rack and equipment layouts, controls and interlock electronics, and the
features of the operator interface for programming the current ramps and
adjusting the timing of the system triggers.
Presentation
Recent machine and beam
line optics developments in the Antiproton Source
Vladimir Nagaslaev
(Fermilab)
Abstract
Antiproton production at Fermilab is a multistage process that uses 2 cooling rings and more than a kilometer of beam lines. During recent years numerous efforts and developments were put forward in order to substantially increase the production rate.
One of important parts of these efforts was the optics developments, such as improving machines acceptance, optimizing beam parameters for the stochastic cooling and optical matching of the beam lines. The current status of this work and plans for the near future are presented.
Presentation
Experimental Optimization of TTF2 RF Photoinjector
and Bunch Compressors
Yujong Kim,
Free Electron Laser Laboratory,
Duke University
Abstract
To develop various technologies for a future linear collider and the European X-ray Free Electron Laser, conversion of DESY TESLA Test Facility
(TTF) into its phase 2 (TTF2 / FLASH) was started in 2002. To get an FEL lasing and a saturation of FEL power within a 30 m long undulator, highly dense and cold beams with a high peak current, a low energy spread, and a low emittance should be sent to the undulator. In 2004, commissioning of a new L-band RF gun, a new superconducting booster linac (ACC1), and two new bunch compressors were started to supply suchlike beams. During this talk, speaker will shortly introduce TTF2, RF photoinjector, and bunch compressors. Then, speaker will talk about various commissioning experiences of TTF2 RF photoinjector and the first experimental demonstration of a strong emittance damping along the booster linac to generate a ultra-low normalized transverse emittance of about 1 mm.mrad for 1 nC and 4.4 ps rms long electron beams. Finally, speaker will talk about experimental optimization of TTF2 bunch compressors to generate femtosecond long electron beams.
Presentation
Accelerator Driven Nuclear Energy - The Thorium Option
Rajendran Raja
Abstract
A Fast Chopper for the HINS
Robyn Madrak
Abstract
Fermilab is currently constructing a 65 MeV H- Linac. This is an R&D project demonstrating the feasability of a new type of Front End for an 8 GeV superconducting Linac, which
could deliver beam to the Fermilab Main Injector. Since the Linac
and Main Injector will operate at different frequencies, approximately 1 of
every 6 linac bunches (at 325 MHz) will need to be
removed, in order to avoid losses in the Main Injector, which operates at 53
MHz. For this purpose, we are in the process of designing and fabricating a
chopper which will apply an electrostatic kick to bunches in the 2.5 MeV MEBT section of the Linac. We
discuss the design parameters for the chopper, the design and prototypes of the
travelling wave meander structure which will apply the kick, and progress on
the fast, high power pulser which will supply pulses
to the chopper structure.
Presentation
LHC Commissioning and Status
Lucio Rossi
Abstract
Presentation
Test automation, quality control and simulation of superconductors
Vito Lombardo
Abstract
To achieve a full understanding of accelerator magnets
behavior, it is important to test and characterize superconducting strands and
Rutherford-type cables used in the coils. All existing hadronic
accelerators employ a magnet technology based on NbTi
strands. However, NbTi has reached its limit,
providing a nominal field of 8.4 T in superfluid
Helium for the Large Hadron Collider (LHC). To
increase the operating field and push the energy envelope, new superconductors
with better properties will be needed. Fermilab is currently involved in
developing the next generation of high field magnets with nominal fields of
10-15 T using Nb3Sn, Nb3Al and High Temperature Superconductors. Solutions to
automate data acquisition and test procedures on two cryogenic short sample
test stations of TD Superconductor R&D lab are presented for critical
current measurements as well as RRR and low field instability. Temperature
control, data fitting, analysis and storing procedures as well as ha rdware and software quench protection systems have been
embedded to keep the human intervention as low as possible. Applications and
results are shown. The cable fabrication procedure used at Fermilab is then
described, together with a laser based solution for online measurement of the
geometry of the cable itself. Finally, results of simulations of
electromagnetic and thermal processes in Rutherford- type cables are presented.
Presentation
Status/Plans for Technical Division
Marc Ross
Abstract
The talk presents the current status and plans for the
Technical Division.
Elastic Splashes
Torben P. Grumstrup
Abstract
When a falling drop impacts a thin liquid surface, the
resultant splash involves the competition of inertia, viscosity, and surface
tension; in certain limits the familiar crown-shaped splash results. In the
case of viscoelastic liquids (either polymer or micellar) there is typically much less of a splash due to
the high extensional viscosity of these fluids. Here, a novel cross between
these two cases is presented: the splash of two Newtonian liquids which only
become viscoelastic during the splash. A high-speed
digital video camera is used to capture the splash caused by a drop of sodium salicylate solution falling onto a film of cetyltrimethylammonium bromide solution. When the two
combine, microscopic tubes called worm-like micelles form, causing the liquid
mixture to exhibit viscoelastic properties. The
elasticity of the liquid results in formation of stable liquid filaments and
the "beads-on-a-string" phenomenon -- behavior which would not occur
in a Newtonian liquid such as water.
Presentation
Electron Cloud measurements in the
High-Current Experiment
Michel Kireeff Covo
University of California at Berkeley, Department of Nuclear Engineering, 4155 Etcheverry Hall, MC 1730, Berkeley, California 94720, USA
Abstract
The High Current Experiment (HCX) at LBNL is a driver scale single beam injector that provides a 1 MeV K+ ion beam current of 0.18 A for 5 µs. It transports high-current beams with large fill factor (ratio of the maximum beam envelope radius to the beam pipe radius) and low emittance growth that are required to keep the cost of the power plant competitive and to satisfy the target requirements of focusing ion beams to high-power density. Beam interaction with the background gas and walls desorbs electrons that can multiply and accumulate, creating an electron cloud. This ubiquitous effect grows at higher fill factors and degrades the quality of the beam. A review of the instrumentation tools used to measure electron production, accumulation and its properties will be presented and discussed.
Presentation
Measurements and Data Analysis in LHC
Superconducting Magnets
CERN
Abstract
The assessment of the training quench performance and
of the field quality of the LHC magnets belong to the acceptance criteria to qualify
the dipoles and the quadrupoles for the LHC machine.
One source of the quench at 1.9 K is the release of the transient energy
induced by mechanical perturbations (spikes) during the magnet powering. These
disturbances are localized and studied through voltage signals recorded
across the magnet coils and through signals coming from a quench antenna. A new
measurement station implemented to record the spike events with a high sample
rate and a new analysis method based on the Continuous Wavelet Transform are
described. Results of measurements carried out on LHC dipoles are presented as
well as the statistical treatment of the data in order to understand the impact
of the spikes to the so called training phenomenon.
Un-corrected static and dynamic magnetic field errors
can also degrade the machine performance. The ramp rate induced field errors
and the AC energy loss were studied on the main LHC quadrupoles
and dipoles. The experimental set–up and the results are compared to the values
specified from the beam tolerances.
Presentation
Metamaterial-loaded Waveguides for
Accelerator Applications
Sergey Antipov
ANL
Abstract
Material properties are central to the field of accelerator physics. One area of advanced accelerator research is to investigate novel materials and structures and their potential use in extending capabilities of accelerator components. Within the past decade a new type of artificially constructed material (metamaterial, MTM) having the unique property of simultaneously negative permittivity and permeability has been realized, and is under intense investigation, primarily by the optical physics and microwave engineering communities. Metamaterials can be customized to have the permittivity and permeability desired for a particular application. Some unusual effects can be demonstrated in metamaterials, like negative refraction and backward Cherenkov radiation.
An investigation of metamaterials in the context of accelerator physics is
being carried out by IIT and the Argonne Wakefield Accelerator Facility.
Artificial materials have potential applications in active and passive devices
at millimeter waves and at much higher frequencies. Waveguides loaded with metamaterials are of interest because the metamaterials can change the dispersion relation of the
waveguide significantly. For example, slow backward waves can be produced in a
MTM-loaded waveguide without having corrugations. The dispersion relation of a
MTM-loaded waveguide has several interesting frequency bands.
Presentation
D. Marreiro
Illinois Institute of Technology
Abstract
The main
objective of this work is to demonstrate the validity of a Poisson
Particle-Particle--Particle-Mesh (P3M) coupled with a Brownian
Dynamics (BD) engine simulation tool in modeling charge transport in biological
ion channels. The challenges of ion channel modeling are presented with the
underlying physical considerations. The details of the P3M
force field scheme and its implementation are presented. The BD algorithm and
the various integration schemes for the particle dynamics are presented and
compared. The numerical model proposed for the electrolyte solution, the
membrane and the ion channel are discussed. A set of benchmarks are
defined and motivated to validate the numerical representation of the
system. Analytical models are proposed for the electrolyte solution in
bulk and interfacial conditions: the Hypernetted
Chain (HNC) approximation is used in conjunction with the Ornstein-Zernike
integral equation theory to describe the electrolyte solution, and provide a
comparison with the simulation results. Similarly, the Gouy-Chapman
Double Layer (DL) theory is used to compute analytical benchmarks for the
membrane-solution interface simulation. The P3M BD simulation of
bulk electrolyte solutions and membrane-solution interfaces is validated by
comparison with the proposed analytical benchmarks. The range of valid
numerical parameters for the system is determined by defining and applying an
error analysis methodology. Subsequently, the well-studied OmpF porin channel from bacterium
E. Coli is used as a test case to validate the proposed charge transport
simulation approach. Potential mapping of the pore is performed for different
ion types. Dynamic charge transport simulations are performed, and macroscopic
channel conductance values are extracted and compared with published
experimental measurements as well as other numerical models. The applicability
of the P3M BD simulation is discussed, and compared with other
numerical models from the computational cost standpoint. Finally, ways to
improve the algorithmic efficiency and accuracy of the simulation are
introduced.
Presentation
or Muon Collider
Derun Li
Center
for Beam Physics
Abstract
Neutrino physics has become increasingly interesting to the high-energy
physics community, as it may provide clues to new physics beyond the standard
model. The physics potential of a Neutrino Factory, a facility to produce
high-energy, high-intensity, high-brightness neutrino beams from decays of muons stored in a muon storage
ring, is thus very high. There has been a global R&D effort aimed at a
Neutrino Factory design that meets the physics requirements and addresses the
key technologies, such as targetry, muon ionization cooling and acceleration. In this
presentation, I will give a brief introduction on R&D programs under the US
Neutrino Factory and Muon Collider Collaboration
(NFMCC), muon ionization cooling channel,
international MICE experiment, with emphasis on high gradient normal conducting
RF cavity R&D for muon ionization cooling
channel, explain RF challenges for cavity design, fabrication, and operation
for the muon cooling channels.
A Beam Condition
Monitoring System for the CDF Experiment
R. Wallny
(UCLA)
Abstract
Particle physics collider experiments at the high energy frontier are being
performed today and in the next decade in increasingly harsh radiation
environments. While designing detector systems adequate to these conditions
provides a challenge in itself, their safe operation relies heavily on fast
beam monitoring systems using novel radiation hard technologies to protect
these expensive devices from beam accidents. The talk will present a beam
condition monitoring (BCM) system based on polycrystalline chemical vapor
deposition (pCVD) diamond sensors designed for the
Collider Detector at Fermilab (CDF) experiment operating at Fermilab's
Tevatron proton-antiproton synchrotron. We report our
operational experience with this system which was installed in spring of last
year. The system currently represents the largest of its kind operated at a hadron collider and is similar to designs being pursued by
the next generation hadron collider experiments at
the Large Hadron Collider (LHC).
Six Dimensional
Phase Space Cooling Simulation for a Muon Collider
K. Yonehara
(Fermilab)
Abstract
Fast beam phase space cooling is an essential requirement for a muon collider. The only practical method for muon beam cooling is Ionization Cooling (IC), in which muons lose all components of momentum by ionizing an
absorber material but only the longitudinal momentum is replaced by RF
cavities. This reduces the angular spread of the beam to the point that heating
from multiple /Coulomb scattering exactly opposes IC. This technique only
cools transversely; to cool the longitudinal emittance
it must be exchanged with the transverse emittance
where ionization cooling is effective. A helical cooling channel (HCC) is made
with a special magnetic field formed by helical dipole and quadrupole
magnets combined with a solenoidal magnet to provide
this emittance exchange using a continuous
homogeneous absorber.< SPAN style="mso-spacerun:
yes"> New magnet inventions and old precooling
concepts have inspired a practical cooling channel, which has exceptional six
dimensional emittance cooling. I will describe the
current status of the HCC simulation studies and discuss MANX, a proposed HCC
experiment.
Presentation
Observations of
Proton Reflection on Bent
W.Scandale (CERN)
for the H8-RD22
collaboration
Abstract
We
report observations, performed by the H8-RD22 Collaboration, of the so-called
volume reflection effect with 400 GeV/c protons
interacting with bent Silicon crystals in the H8 beam line at the CERN SPS. The
volume reflection is closely related with particle channeling. This phenomenon
occurs at the tangency point of a particle trajectory with the bent crystalline
planes and consists in the reversal of the transverse component of the particle
momentum. The measurements were collected with a high spatial resolution
detector mainly based on Silicon strips. The proton beam was deviated in the
direction opposite to that of channeling by ~12murad, which is ~1.3 times the
critical angle, with an efficiency larger than 97% in a range of the
proton-to-crystal incident angle as large as the bending angle of
crystallographic planes. This evidence opens new perspectives for manipulation
of high-energy beams, e.g., for collimation and extraction in the
new-generation of hadron colliders or as a method for
high-energy experiments in the region near to the circulating beam.
Presentation
Note Location & Time Changed **
**Location 1-West**
Time 2pm
J-PARC Status and
Channeling Experiments in
Shin'ya Sawada
(KEK)
Abstract
Superconducting RF cavities and materials
issues
Claire Antoine
(Saclay/Fermilab)
Abstract
The employ of Superconducting Radiofrequency cavities
is main technology asset for the next generation international collider ILC.
SRF technology is also widely used or foreseen in other particles accelerators,
such as light sources (synchrotron, SASE-FEL, ERL) or high power hadrons beams
for neutron sources and nuclear physics (SNS, ATLAS, RIA). Any of these
applications can be very demanding in terms of specific performance, i.e. high
accelerating gradient and/or low losses, but some of these specifications,
achieved on lab scale, are not yet met on an industrial scale. Basic R&D on
the material is a way to better understand the origin of degradation or
dispersion of performances, and how to overcome it.
As a first step we will describe shortly the main
particularities of RF superconductivity, then we will retrace the last 15 years
of SRF R&D, and we will try to show how a better understanding of the
physics of the RF superconductivity helped to overcome technical limitations.
In the third part we will try to summarize the latest issues in cavities
performances, well as the main research directions that need to be pursued.
ALTERNATIVE RF
SOLUTIONS FOR HIGH GRADIENT INVESTIGATIONS
Vyacheslav P. Yakovlev
Omega-P, Inc.,
Abstract
Several RF technical
alternative solutions are discussed for elements of future high-gradient linear
accelerators, including RF sources and RF pulse manipulation systems. The
current state of development is summarized for high-power, high efficiency magnicons at X-band, Ka-band, and L-band as RF sources for
high-gradient R&D and linear collider applications. A new concept of
an active RF pulse compressor based on use of newly-developed, ultra-fast,
electrically-controlled ferroelectric elements is described. Finally,
designs of fast, low-loss, external ferroelectric tuners are described to
provide rapid, precise phase and amplitude control of SC RF cavities of ILC.
The Second Low Emittance
Muon Collider Workshop
Rolland Johnson
Muons, Inc
Abstract
We report on the considerable progress that has been made
since the first Low Emittance Muon
Collider workshop, which explored the consequences of extreme beam cooling in
order to get high luminosity with fewer muons. Recent
measurements on high-gradient hydrogen-pressurized RF cavities and designs of
high-field high-temperature superconducting magnets show great promise for
effective muon cooling. A momentum-dependent
version of the original helical cooling channel has been developed
into a 6-dimensional demonstration experiment with an elegant magnet
configuration that includes emittance matching.
Increased workshop involvement by the high energy physics community has
generated enthusiasm to reexamine the theoretical goals and experimental
possibilities for this new kind of energy-frontier muon
collider, which can use ILC accelerating structures.
Muon cooling and future muon
facilities
Daniel M. Kaplan
Illinois Institute of Technology
Abstract
Muon colliders and neutrino factories are attractive options for future facilities aimed at achieving the highest lepton-antilepton collision energies and precision measurements of parameters of the neutrino mixing matrix. The performance and cost of these depend sensitively on how well a beam of muons can be cooled. Recent progress in muon cooling design studies and prototype tests nourishes the hope that such facilities can be built during the next decade. The status of the key technologies and their various demonstration experiments will be summarized.
Performance of
the LHC Injectors and Intensity limitations
Gianluigi Arduini
CERN
Note Location & Time Changed **
**Location 1-West**
Time 10am
February 08, 2007
Overview of the
High Intensity Neutrino Source
Jean-Paul Carneiro
(FNAL)
Abstract
FNAL is developing the
design and technology of an 8 GeV H-minus
superconducting linac with a primary mission of
increasing the intensity of the Main Injector for the neutrino program. Considerable
effort has gone into the development, cross-checking, and utilization of
simulation codes. Start-to-end simulations, from the RFQ to the Main Injector
stripping foil, using the codes TRACK (ANL), ASTRA (DESY) and ELEGANT (ANL)
will be presented to provide a detailed description of this accelerator. The
scope and status of the linac front-end currently
being built at the
February 01, 2007
Beam control and monitoring with FPGA-based
electronics: status and
Perspectives
Nathan Eddy
FNAL
Abstract
Modern FPGAs
support designs using roughly 10^6 logic gates, pipeline speeds exceeding 200
MHz, internal SRAM, dedicated multipliers for signal processing, clock
generation using phase-locked loops, and a variety of single-ended and
differential I/O standards, including fast serial links. When interfaced
with high-speed ADCs, DACs, and other components
commonly found in telecom applications, FPGAs
facilitate a wide range of beam control and monitoring applications.
Examples include beam-position measurement, low-level RF control, instability
damping, and manipulation of accelerator timing signals. Once signals of
interest are in digital form, an instrument's FPGA logic and memory provide a
natural means to capture data for remote diagnosis--both of beam behavior and
of the instrument itself. Finally, FPGA-based solutions provide a
flexible, reconfigurable, and reusable toolkit for instrumentation: existing
modules are often adapted to implement new applications, and useful code
fragments can be quickly copied from design to design.
The Future of
Accelerator R&D at Fermilab
Steve Holmes
(FNAL)
Abstract
January 23, 2007
Electron-Proton Dynamics
for Long Proton Bunches in High Intensity Proton Rings
Yoichi Sato
Abstract
Electron clouds in intense
space charge dominated proton beams may cause instabilities and emittance growth. Colleagues at the Oak Ridge National
Laboratory (ORNL) and I have developed an electron cloud module and implemented
it into the ORBIT Code for beam dynamics in high intensity rings.
This electron cloud
module includes full 3D descriptions of the proton beam bunch and the electron
cloud, including their space charge interactions and their motion in external
electric and magnetic fields.
The two main sources of
electrons are primary electrons caused by lost protons hitting the vacuum
chamber walls and secondary emitted electrons caused by electrons hitting the
wall. For the latter we adopt a set of models based on those of M. Pivi and M. Furman.
This seminar presents
the development of the new electron cloud module, including benchmarks
demonstrating its capability to examine the effects of the electron cloud on
the proton beam and simulation studies of electron cloud dynamics. These
studies include the sensitivity of the electron cloud properties to different
proton beam profiles and reproduction of experimental results from the proton
storage ring at Los Alamos National Laboratory. A possible idea to reduce the
electron cloud effect in the vacuum chamber is also proposed. It will be
applicable to many existing devices easily.
Presentation
Longitudinal
electron bunch diagnostics using coherent transition radiation
Daniel Mihalcea
FNAL
Abstract
The longitudinal charge
distribution of electron bunches in the Fermilab A0 photo-injector was
determined using the coherent transition radiation produced by electrons
passing through a thin metallic foil. The auto-correlation of the transition
radiation signal was measured with a Michelson-type interferometer. The
response function of the interferometer was determined from measured and
simulated power spectra for low electron bunch charge and maximum longitudinal
compression. Kramers-Kronig technique was used to
determine longitudinal charge distribution. Measurements were performed for
electron bunch lengths in the range from 0.3 to 2 ps
(rms).
January 04, 2007
Essential features
of LARP strands and prospects for still better high-field
Lance Cooley
Condensed Matter Physics and
Materials Science Department
Brookhaven National
Laboratory
Abstract
Since the late 1990s, work
spearheaded by advanced technology development programs in the DOE Office of
High Energy Physics has led to the doubling of the critical current density of
Nb3Sn superconducting wire at 12 T, 4.2 K. As a result of this work,
suppliers of reproducible, reliable, high-performance Nb3Sn strand for advanced
high-field magnet development now exist. The strand design for the LHC
Accelerator Research Program (LARP) typifies many of the critical advances, and
I will describe the general features that enable its success and present an
overview of the materials science beneath them. I will argue that ample
room exists for continued innovation, improved margins, and cost
reduction. Other drivers, such as a very high field solenoid for muon cooling or the development of superconducting RF
cavities beyond pure Nb, may pull the attention of
the materials community away from further developing Nb3Sn strand, and I will
briefly describe emerging areas in high-field superconducting materials.
Talks in 2006
Main Injector
Digital Dampers
Dr. Phil Adamson
(
Abstract
The Main Injector digital
damper system has been essential in allowing the MI to reach beam intensities
of over 3E13 protons. The present system is described, and upgrade plans for
the proton plan and SNuMI eras are detailed.
Presentation
Results in the 3-D simulation for Booster
Xi Yang
FNAL
Abstract
In order to have a better understanding of the FermiLab Booster beam loss at the injection, emittance growth at the transition crossing, and momentum spread reduction at the extraction, we need a 3-D model which includes the longitudinal and transverse space charge effect and the longitudinal impedance effect. After we’ve successfully bench marked the longitudinal motion model against the experiment (see the accelerator physics and technology seminar at 09/02/06), it has been added to the particle tracking code STRUCT. Also, a simplified transverse space charge model has been added to STRUCT. Based upon our simulation, the momentum reduction at the extraction is optimized operationally to reduce the beam loss during Slip Stacking in the Main Injector. We obtained a good agreement between experiment and simulation at injection and extraction. We’re ready to include the longitudinal impedance module and nonlinear chromatic effect at the transition in STRUCT.
The CDF Roman-Pot Detectors
Mary Convery
FNAL
Abstract
Roman-pot detectors located
in the Tevatron tunnel in the downstream antiproton
direction were used in Run IIa as part of the CDF
diffractive physics program. The concept of a Roman-pot detector will be
discussed, as well as the specific design of the CDF pots. The
reconstruction of the kinematics of diffractively-scattered antiprotons using
tracks in the RP detectors and transporting back through the Tevatron magnets between the pots and the interaction point
will be described. Issues related to beam backgrounds and the operation
of readout electronics in a high-radiation environment will be touched upon,
and a brief comparison to the D0 forward detectors will be given.
Diffractive physics results using the Roman pots will be presented.
Presentation
Beam control and monitoring with FPGA-based
electronics: status and
Perspectives
Nathan Eddy
FNAL
Abstract
Modern FPGAs
support designs using roughly 10^6 logic gates, pipeline speeds exceeding 200
MHz, internal SRAM, dedicated multipliers for signal processing, clock
generation using phase-locked loops, and a variety of single-ended and
differential I/O standards, including fast serial links. When interfaced
with high-speed ADCs, DACs, and other components
commonly found in telecom applications, FPGAs
facilitate a wide range of beam control and monitoring applications.
Examples include beam-position measurement, low-level RF control, instability
damping, and manipulation of accelerator timing signals. Once signals of
interest are in digital form, an instrument's FPGA logic and memory provide a
natural means to capture data for remote diagnosis--both of beam behavior and
of the instrument itself. Finally, FPGA-based solutions provide a
flexible, reconfigurable, and reusable toolkit for instrumentation: existing
modules are often adapted to implement new applications, and useful code
fragments can be quickly copied from design to design.
Presentation
Accelerator Vacuum 101 Made Easy
Terry Anderson
FNAL
Abstract
This
talk presents a condensed, simplified, and practical discussion of the
principles, procedures, and operating parameters of particle accelerator vacuum
systems as practiced at Fermilab. It is intended to provide a basis for designers,
builders, and operators of accelerator systems to communicate with each other
about the needs and impact of the vacuum system. Rigorous analytical
development of the equations and concepts are not given. It is assumed
that the reader has some limited understanding of the subject. References
for further study are given in the appendix.
Presentation
November 09, 2006
Electromagnetic and Mechanical Properties
of Superconducting Spoke-Loaded Cavities
Zachary Conway
ANL/UIUC
Abstract
External forces excite mechanical vibrations in superconducting cavities and lead to cavity RF frequency variations. The RF control system must be able to accommodate these frequency variations in order to limit RF field phase and amplitude errors. Traditionally this was done by increasing the power output of the RF power source. Another option is to operate fast mechanical tuners to counterbalance the cavity frequency variation. This presentation reports on measurements of the external forces, which couple to the cavity RF field, and on the fast mechanical tuning systems used to counterbalance their effects for spoke-loaded intermediate-b superconducting cavities being developed for both cw and pulsed operation. These cavities are of broad interest for new high-energy ion and proton linacs.
Presentation
November 02, 2006
The MI Wide Aperture Quadrupole
(WQB) Project
FNAL
Abstract
In the design stage of the Main Injector it was recognized that the old Main Ring quadrupoles would pose an aperture limit at the injection and extraction points, especially at the locations where they are positioned between two Lambertson magnets. With the increasing beam intensities required to support neutrino production in the NuMI beam line, the problem became more pressing. This deficiency has now been corrected by replacing those limiting magnets with newly designed and constructed quadrupoles that have the same length and integrated gradient as the old magnets, run on the same bus, but have a pole tip diameter greater by 32%. We will describe the magnet design, construction, measurement, installation, and operation, as well as demonstrating success in matching the Main Injector optics and increasing the aperture.
October 24, 2006
H- laser stripping experiments
at SNS
V. Danilov
ORNL,
Abstract
Thin carbon foils are used as strippers for charge exchange injection into high intensity proton rings. However, the stripping foils become radioactive and produce uncontrolled beam loss, which is one of the main factors limiting beam power in high intensity proton rings. Recently, SNS accelerator team presented a scheme for laser stripping of an H- beam for the SNS ring. First, H- atoms are converted to H0 by a magnetic field, then H0 atoms are excited from the ground state to the upper levels by a laser, and the excited states are converted to protons by a magnetic field. This paper presents the results of the SNS laser stripping proof-of-principle experiment. The experimental setup is described, and possible explanations of the data are discussed.
Presentation
October 19, 2006
Electron cooling at
the Recycler: Update and Cooling force characterization
Lionel Prost
FNAL
Abstract
Electron cooling of 8 GeV antiprotons at Fermilab’s
Recycler storage ring is now routinely used in the collider operation. It
requires a 0.1-0.5 A, 4.3 MeV dc electron beam and is
designed to increase the longitudinal phase-space density of the circulating
antiproton beam. I will briefly describes the characteristics of the electron
beam that were achieved to successfully cool antiprotons. Then, results from
various cooling force measurements along with comparison to a non-magnetized
model are presented. Finally, operational aspects of the implementation of
electron cooling at the Recycler are discussed, such as adjustments to the
cooling rate and the influence of the electron beam on the antiproton beam
lifetime.
Presentation
Analysis of
beam-beam diffusion effects in RHIC and the LHC
Vahid Ranjbar
FNAL
Abstract
The Diffusion analysis
approach to lifetime calculations allow a significant reduction in the time and
computing power usually necessary to perform direct lifetime calculations. We
report on results of diffusion analysis for RHIC and the LHC and consider the
range of validity for this approach.
NEW MATERIALS AND
DESIGNS FOR HIGH-POWER, FAST PHASE SHIFTERS
Robin Madrak
FNAL
Abstract
In the 100 MeV H- Linac to be constructed at
Fermilab, the use of fast ferrite high power phase shifters will allow all of
the accelerating RF cavities to be driven by a single 2.5 MW, 325 MHz klystron.
This results in substantial cost savings. The shifters are coaxial with
aluminum doped Yttrium Iron Garnet (YIG) ferrite. In combination with branch
line couplers, they will provide independent phase and amplitude control for
each cavity. This is achieved by adjusting the solenoidal
magnetic field applied to the ferrite. We report on our results in both low
power (timing) and high power tests, for both 3?? and 1- 5/8?? OD phase
shifters. The low power measurements demonstrate that the rate of phase shift
is well within the spec of 1 degree/µs. The high power tests were performed at
the Advanced Photon Source at Argonne National Lab. We measured phase shifts
and the failure point (applied power) for tuners in various configurations. In
addition, we performed phase and amplitude measurements for a setup consisting
of a 1-5/8??OD phase shifter along with a prototype branch line coupler.
Beam Commissioning
Software Developed by Fermilab for the LHC
David McGinnis
FNAL
Abstract
Fermilab wants to be involved in the
commissioning and operations of the LHC. For example, we are making a
substantial investment in remote operations. It is difficult for outside
visitors from other labs to make important contributions once beam commissioning
has started. These difficulties arise because visitors are usually unfamiliar
with the control system and critical problems are usually assigned to in-house
staff. However, Fermilab will be much more welcomed at CERN if it can
bring real resources to the table and has the ability to solve
operational problems. One possibility is to develop a suite of software
products to enable Fermilab accelerator physicists to make key contributions to
the beam commissioning of the LHC. This talk will describe possible software
products and a possible organization for developing these products. People who
are willing to work on these projects are encouraged to attend this talk.
September 21, 2006
Run II Status and Future Development: Can
We Achieve 8 fb-1
Valeri Lebedev
FNAL
Abstract
Present status of Run II program and further development aimed to achieve the planned Run II luminosity integral will be discussed. Recent machine performance assures us that we can achieve 4-5 fb-1 of integrated luminosity by the end of FY-2009 with minimum development. However the upgrade path we are currently pursuing should allow us to achieve 7-8 fb-1. Major contributions should come from increase of stacking rate in Antiproton source, fast and more efficient Accumulator-to-Recycler transfers and improvements in Tevatron.
September 14, 2006
R & D in RF
Superconductivity at
Walter Hartung
Abstract
A program of research and
development in superconducting radio-frequency cavities at MSU began in the
year 2000. The primary goal is to support the design and construction of
a next-generation superconducting linac for heavy
ions, although the technology is also suitable for protons. A number of
prototype cavities have been designed, fabricated, and tested. These
include quarter-wave resonators, a half-wave resonator, and elliptical
cavities. The elliptical cavities for heavy ions are at 805 MHz, but MSU
is also prototyping an elliptical cavity at 1300 MHz to assist with the Fermilab
Proton Driver effort. Two prototype cryomodules
for a heavy ion linac have been designed; the first
(containing 2 multi-cell elliptical cavities) was completed and tested, and the
second (containing a quarter-wave resonator, a half-wave resonator, and 2 superconducting
magnets) is being fabricated. Research is also underway in x-ray imaging
of cavities, heat transfer in cavities, materials and surface studies,
alternative cavity designs, alternative cavity fabrication techniques,
liquid-helium-filled cavities, and other areas.
September 7, 2006
RF Breakdown and High Gradient Limits
Jim Norem
ANL
Abstract
The MuCool program has an experimental program to study the problem of maintaining high gradients in low frequency rf systems, an important constraint on Muon Cooling. We have also started modeling and material science studies to support this effort. Initial modeling showed that tensile stresses are important in breakdown, however we have extended the model to study the equilibrium that develops between surface damage and structure performance. Our model seems to be able to calculate all aspects of rf structure performance, with precision that is limited by a few specific measurements. The model should apply to some aspects of CLIC and ILC operation, and a variety of other high gradient systems.
Simulation of
transition crossing in the Fermilab Booster
Xi Yang
FNAL
Abstract
In order to build a realistic model for Booster transition crossing, we are updating a particle tracking code STRUCT to 3-D simulation code by adding a longitudinal motion model. The model responsible for the beam acceleration includes space charge effect, Gamma-t transition-jump, and the radial feedback system. It has been bench marked against the experiment in the charge transmission vs. the beam intensity and the excitation of bunch length oscillations after transition. It has been applied to investigate the influence of radial feedback gain on the charge transmission, energy error, and beam parameters; the influence of the transition-jump system on the bunch length and momentum spread at transition; and the influence of the phase-jump speed at transition on beam parameters. We are in the process of building a 3-D model for Booster.
The History of H- Source Development
J. Peters
DESY
Abstract
The rich history of H-
source development is presented highlighting the most successful designs. The
operating principles of the two families of sources, surface (magnetron and
penning) and volume, are explained.
Important design principles
and the construction of sources, including several types of discharge chambers
and of hybrid chamber arrangements, will be shown. The optimisation
of RF source-design will be presented, in particular the antenna coupling, the
choice of frequency range, and the design of the extraction plasma region and
also the results of detailed experimental investigations of the plasma
parameters with laser photo-detachment and Langmuir probes. Finally a
practically maintenance free high current RF H- source is presented.
Presentation
MDI Studies at the ILC and related test
beam program at SLAC's End Station A Facility
Michael Woods
SLAC
Abstract
The design of the International Linear Collider impacts Detector design and physics capability beyond the delivered luminosity and energy reach. Machine-Detector Interface (MDI) work for the ILC includes:
I’ll discuss these MDI aspects for the ILC and related beam tests in the SLAC End Station A facility.
August 17, 2006
Improving the
performance of SRF cavities and other high voltage electrodes by treating the
surfaces with Gas Cluster Ion Beams (GCIB): Can a perfect electrode be
manufactured and tested?
David R. Swenson
(Epion
Corporation)
Abstract
Gas cluster ion beams (GCIB)
is a new nano-technology that smoothes, etches,
and/or chemically alters a surface by bombarding the surface with an energetic
charged particle beam of cluster ions (~5,000 atoms/cluster). It has
drastically reduced DC field emission of stainless steel electrode material
used for high field electron injectors[1]. For SRF cavity surface
preparation, GCIB can remove sub-micron scale asperities [2] and can reduce nano-scale roughness to atomic level smoothness on planar
and non-planar surfaces. GCIB also has the desirable feature that
it is applied under high vacuum conditions so it can be used as the very last
conditioning step before cavity operation. We have studied GCIB
treatments of BCP polished Nb samples using Ar, O2, or O2+NF3 clusters accelerated with voltages up to
35 kV. The samples have been evaluated using scanning field emission
microscopy (SFEM) as well as AFM, SEM and SIMS. Etch rates have been
measured using a quartz-crystal microbalance. The measurements show a
dramatic and reproducible reduction in the number of field emission sites on
GCIB treated surfaces, and show an alteration of oxide stoichiometry.
We are continuing our investigation of the effect of GCIB on the grain
structure produced by BCP polishing.[2] A GCIB etch rate of 5 nm cm^2
s^-1 for Nb has been measured using a small-test
stand source, indicating that 50 nm can easily be etched from the entire
surface of a typical cavity in a period of several hours. There are
excellent prospects that the etch rate can substantially increased and Epion Corporation is developing a beam delivery system for
treating the inside of SRF cavities using GCIB.
[1] D.R. Swenson, E. Degenkolb, Z. Insepov, L. Laurent and G.
Scheitrum, Nucl. Instr.
and Meth. B 241 (2005) 641 [2] D.R. Swenson,
Presentation
Muon Beam Cooling for Colliders, Neutrino Factories, and
Experiments
Rolland Johnson
(Muons, Inc)
Abstract
Bright muon beams are needed for muon colliders and are useful for neutrino factories and
new muon decay experiments. A new technique
to achieve very effective six-dimensional (6D) muon
beam cooling is based on a helical cooling channel (HCC) [1] composed of
superimposed solenoidal, helical dipole, and helical quadrupole magnetic fields. The Muon And Neutrino eXperiment
(MANX) which is being designed to demonstrate the use of this HCC technique
will be described as will several complementary hardware and software
innovations and projects [2].
[1] Y. Derbenev and R.
P. Johnson; PRSTAB 8, 041002 (2005)
http://www.muonsinc.com/reports/PRSTAB-HCCtheory.pdf
[2] R. P. Johnson, A Short Overview of Muons, Inc. Projects and Proposals, http://www.muonsinc.com/reports/Eleven%20Muons,%20Inc.%20projects%20and%20proposals.pdf
Presentation
August 08, 2006
Operating the D0 Detector
Bill Lee
(FNAL)
Abstract
The D0 detector is a general
purpose detector designed to detect signals from a wide variety of physics
processes from proton-antiproton collisions at the Tevatron.
In order to to make the best use of the collisions
provided, it is important to keep the detector in the best
possible operating
condition. Detector operations and the challenges
of making most efficient use
of the delivered collisions will be addressed.
Do we need more accelerator research? - Situation at
Fermilab and highlights from 2006 Advanced Accelerator Concepts workshop
Vladimir Shiltsev
(FNAL)
Abstract
I will give a brief overview
of recent developments in advanced accelerator schemes presented at AAC'06 and
discuss whether Fermilab needs to expand beam physics research and possible
directions for that.