[Tpe] Tagger shielding - for TPE

[Larry Weinstein]

Dear Folks,

We plan to run with 100 nA on a 2% radiator for 30 days.  EG3 ran with 
50 nA on 5x10-4 and g11 ran with 60 nA on 10-4.  The TPE photon 
luminosity is about 100 times normal running (one month is equivalent to 
about 10 years).  However, there is a large difference (factor of at 
least ten) in the count rate from the high end of the tagger to the low 
end.  CLAS experience with the low photon energy counters indicates that 
the high photon energy counters should not be hurt by one month of TPE 
running.  At worst, we should only need to remove and replace the low 
photon energy scintillators.

I realize that this poses a risk.  However, if we run after every other 
experiment, we will be scooped by Olympus.

- Larry

Eugene Pasyuk wrote:
> This has to be looked at. I suppose background simulation can give an 
> answer about the dose on the scintillators. If it is too high then we 
> should take scintillators out of the box if we want them working after 
> that. This is a substantial amount of work. In terms of scheduling of 
> experiments it would be safer to have all photon experiments run 
> before TPE. If we take scintillators out and then put them back there 
> is a risk that something may get broken in he process.
>
> -Eugene
>
> On 3/25/10 10:22 AM, David Kashy wrote:
>> Hi All,
>> I came up with an idea of how to better shield the tagger hodoscope. It
>> would require making the detector components of the tagger hodoscope
>> inaccessible.
>> Would that be a problem? If not I'd be happy to discuss my shielding
>> scheme.
>>
>> I discussed it briefly with Volker and then he thought that there might
>> be a problem with high doses on the hodoscope scintillators. Has anyone
>> else thought of and studied this?
>>
>> Dave
>>

-- 
				Sincerely,
				Larry

-----------------------------------------------------------
Lawrence Weinstein
University Professor
Physics Department
Old Dominion University
Norfolk, VA 23529
757 683 5803
757 683 5809 (fax)
weinstein at odu.edu
http://www.physics.odu.edu/~weinstei