[Tpe] radiation damage of mylar and kevlar

[Larry Weinstein]

Dear Dave,

My estimate of the total dose so far is about 10% of the TPE exposure.  
With a 2% radiator, the beam is spread out by about 1 cm on the window 
(FWHM).  We would need to raster by more than that to spread it out even 
more.

- Larry

David Kashy wrote:
> Larry,
> These are good finds and give some confidence that the window should
> survive the TPE exposure. I still think it might be worth thinking about
> a small raster across the width of the gap of the tagger to increase the
> exposed area and reduce the peak dose. Can we do this using the standard
> raster magnet if we put the radiator upstream of it? Or are we really
> confident that we are not close to the dose where mylar starts to
> degrade. Someone should make an estimate of the dose received so far .
>
> Thanks
> Dave
>
>
> Larry Weinstein wrote:
>    
>> Dear Dave and Eugene,
>>
>> These are the two articles I found concerning radiation damage of
>> mylar and kevlar.
>> Kevlar was tested up to 200 MRad with no loss of strength.  Mylar was
>> tested up to 1000 MRad with significant loss of strength above 500 MRad.
>>
>> This indicates that the window should be safe with our projected does
>> rates that are 10-20 MRad.  However, on this topic I would much prefer
>> to defer to an expert.
>>
>>      
>    

-- 
				Sincerely,
				Larry

-----------------------------------------------------------
Lawrence Weinstein
University Professor
Physics Department
Old Dominion University
Norfolk, VA 23529
757 683 5803
757 683 3038 (fax)
weinstein at odu.edu
http://www.lions.odu.edu/~lweinste/