|Subject: RE: RE: RE: Linac Mom. Dump Wire .*** Results|
|From: Kamran Vaziri <email@example.com>|
|Date: Mon, 13 Dec 2010 14:51:25 -0600|
|To: 'Fernanda Garcia' <firstname.lastname@example.org>|
It took a while for me to convince myself of the radiation damage results. First here are the residual dose rates.
By HEP, I used the Excel table from the link to wire5 that you sent me on Friday. I assume the wire chamber is in the
Full LINAC beam continuously. By studies, I meant 4 minutes every hour of the full LINAC beam.
I assumed 1 mm spacing, of the wires, with the sigma of the beam about 0.5 cm, but I used the full width at 10th maximum to
estimate the area of the beam in each plane. It turns out that the actual radioactivity of wires is small. The dose rates after
30 days of irradiation and one day of cooling are in micro-rem/hr, for both material. So, from a dose rate point of view, it does not matter which material is used for the wires.
However, the activation levels of the material planes holding the wires and the readout, assuming steel, after one year of irradiation will be 7-9 rem/hr, after one year of irradiation for the HEP. For studies it is a factor of 10 less.
From radiation damage point of view titanium would last about 10 times longer than the BeCu (alloy 171). I don’t know if BeCu wires will last on the average 2+/-1 year.
(sorry I am in a rush, I have to prepare for another talk this week!)
From: Fernanda Garcia [mailto:email@example.com]
Sent: Friday, December 10, 2010 2:34 PM
To: Kamran Vaziri
Subject: Re: RE: RE: Linac Mom. Dump Wire ...l(Last question I hope))
Million Dollars question.... the paddle is 5.5" and I would like to have
at minimum 1 mm apart. However, there is no scanners with this capability.
So, we may have a varied wiring spacing, where the mean where the signal
would be would have the 1 mm spacing and away from the signal
a more wide spacing. However, as you can see form the historical data,
I "don't know" where the profile will be.
Can we make two scenarios: suppose that I will be able to get what I want,
let's make the whole aperture 1 mm apart. Then, we make another assumption
that we have 1 mm convering the central part of the pulse and the wire spacing
will go wider for the tails and ends....Can it work to define a worst, better or
indifferent scenario? Let me know if I am not making sense here....it can be confusing.
Fernanda Gallinucci Garcia
Fermilab MS 307 phone: (630) 840-3798
P.O.Box 500 Fax : (630) 840-4552
Batavia, Il 60510-0500 pager: (630) 218-4361
----- Original Message -----
From: Kamran Vaziri <firstname.lastname@example.org>
Date: Friday, December 10, 2010 2:21 pm
Subject: RE: RE: Linac Mom. Dump Wire ...l(Last question I hope))
To: 'Fernanda Garcia' <email@example.com>
> Hi, Fernanda,
> What is the wire spacing in each plane?
> -----Original Message-----
> From: Fernanda Garcia [mailto:firstname.lastname@example.org]
> Sent: Friday, December 10, 2010 1:22 PM
> To: Kamran Vaziri
> Subject: Re: RE: Linac Mom. Dump Wire ...l(One more question)
> Hm.....this wire is located 6 ft from the downstream end of the
> spectrometer magnet....
> Maybe Rob Reilly can give us the other dimension.
> At the same web page, one link above the Horizontal Wire 5 historical
> data, there is a link
> for Plan view of the new setup of that area. There is some measurement
> on that drawing.
> As far I know at this moment, we are not moving anything from what is
> laid out there.
> Fernanda Gallinucci Garcia
> Fermilab MS 307 phone: (630) 840-3798
> P.O.Box 500 Fax : (630) 840-4552
> Batavia, Il 60510-0500 pager: (630) 218-4361
> ----- Original Message -----
> From: Kamran Vaziri <email@example.com>
> Date: Friday, December 10, 2010 1:18 pm
> Subject: RE: Linac Mom. Dump Wire ...l(One more question)
> To: 'Fernanda Garcia' <firstname.lastname@example.org>
> > Hi, Fernanda,
> > I forgot to ask, how far from the momentum absorber is this going
> > be?
> > There is some back scatter from the absorber that activates the beam
> > pipe etc.
> > Thanks,
> > Kamran
> > -----Original Message-----
> > From: Fernanda Garcia [mailto:email@example.com]
> > Sent: Friday, December 10, 2010 12:05 PM
> > To: Kamran Vaziri
> > Subject: Linac Mom. Dump Wire Material
> > Kamran,
> > Here is the info about the material and thickness
> > Possibility:
> > a) .002" diameter BeCu alloy. BeCu can be
> > soldered and eliminates the need for epoxy bonding so that is our
> > preference. The MTA detectors use BeCu wire.
> > b) there is also a possibility of using .001" and .002" Titanium
> > Titanium must be bonded to
> > the ceramic frame with conductive epoxy. Titanium foil is not available.
> > Which of these options can give less activations in the tunnel and
> > longevity to the wire
> > system if one leaves the wire in the beam path "continuously"?
> > For estimates we should use 2 usec of beam at 15 Hz at 35 mA
> > continuously (HEP condition)
> > Also few minutes at 20 usec, 15 Hz at 35 mA for about 1 hr (studies
> > Thanks,
> > Fernanda
> > Fernanda
> > Fernanda Gallinucci Garcia
> > AD/PS
> > Fermilab MS 307 phone: (630) 840-3798
> > P.O.Box 500 Fax : (630) 840-4552
> > Batavia, Il 60510-0500 pager: (630) 218-4361