Subject: RE: RE: RE: RE: Linac Mom. Dump Wire .*** Results
From: Kamran Vaziri <vaziri@fnal.gov>
Date: Tue, 14 Dec 2010 10:38:29 -0600
To: 'Fernanda Garcia' <fgarcia@fnal.gov>

Hi, Fernanda,

The dose rates are large; several rems per hour. It will reach these levels in a few months. You will need 
At least 10" of steel shielding. 

Cheers,
Kamran 

-----Original Message-----
From: Fernanda Garcia [mailto:fgarcia@fnal.gov] 
Sent: Tuesday, December 14, 2010 10:18 AM
To: Kamran Vaziri
Subject: Re: RE: RE: RE: Linac Mom. Dump Wire .*** Results

Hi Kamran,

Thank you for your study. Question: What about radiation in the enclosure/vicinity
of the wire chamber if one leaves the wires on the beam path all the time?
Is there any concern at this end?
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


----- Original Message -----
From: Kamran Vaziri <vaziri@fnal.gov>
Date: Monday, December 13, 2010 2:51 pm
Subject: RE: RE: RE: Linac Mom. Dump Wire .*** Results
To: 'Fernanda Garcia' <fgarcia@fnal.gov>


Hi, Fernanda,



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!)

Cheers,

Kamran





-----Original Message-----
From: Fernanda Garcia [mailto:fgarcia@fnal.gov]
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





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





----- Original Message -----

From: Kamran Vaziri <vaziri@fnal.gov>

Date: Friday, December 10, 2010 2:21 pm

Subject: RE: RE: Linac Mom. Dump Wire ...l(Last question I hope))

To: 'Fernanda Garcia' <fgarcia@fnal.gov>





Hi, Fernanda,



What is the wire spacing in each plane?



Thanks,

Kamran



-----Original Message-----

From: Fernanda Garcia [mailto:fgarcia@fnal.gov]

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





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





----- Original Message -----

From: Kamran Vaziri <vaziri@fnal.gov>

Date: Friday, December 10, 2010 1:18 pm

Subject: RE: Linac Mom. Dump Wire ...l(One more question)

To: 'Fernanda Garcia' <fgarcia@fnal.gov>





Hi, Fernanda,



I forgot to ask, how far from the  momentum absorber is this going

to

be?

There is some back scatter from the absorber that activates the beam



pipe etc.



Thanks,

Kamran



-----Original Message-----

From: Fernanda Garcia [mailto:fgarcia@fnal.gov]

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

wire.

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

condition)



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


Security, Privacy, Legal