[PRad] beryllium target

[gasparan]

  Hi Stepan,

  You are right about the ERR not mentioning the Be-film target instead 
of the damaged
  C and Al films in the hydrogen gas flow target ladder.
  One of the important advantages of the Be-film, that we want to 
replace, is that the
  thickness is well known (provided by the manufacturer). That, together 
with the lower Z
  (compered with the C or Al) will open up a good experimental chance to 
measure the Moller
  cross section (absolute value) during the GEM efficiency measurements 
(a by-product result,
  will be used during the data analysis process).

  By the way, the Target group provided a Be film target next to LHe4 
target in Hall D
  for our eta radiative width experiment. We used it very successfully to 
measure the
  Compton scattering process to verify and monitor the extracted 
eta-cross section.

  So, unless there are more objections, we would like to ask your 
agreement to use the
  Be-film instead of the damaged C and Al films.

  Thank you for the help,
  Ashot


On 2025-09-03 12:03, Stepan Stepanyan via PRad wrote:
> and I do not see any reference to the Be target in ERR.
> 
> Stepan
> 
>> On Sep 3, 2025, at 12:00 PM, Stepan Stepanyan via PRad
>> <prad at jlab.org> wrote:
>> 
>> Eugene,
>> 
>> I understand lower Z, but has anyone shown that Be vs. Al will make
>> any difference for GEM efficiency calibration?
>> 
>> Stepan
>> 
>> On Sep 3, 2025, at 11:50 AM, Eugene Pasyuk <pasyuk at jlab.org>
>> wrote:
>> 
>> It is not a big complication.
>> Be has a lower Z compared to Carbon, therefore less multiple
>> scattering, the electron beam energy is low. I checked with
>> industrial hygiene. There are just a few things to be done:
>> beryllium awareness training (MED11) for those who will handle the
>> target, and install it in the PRad target chamber (probably 2-3
>> people). Nitril gloves must be used while handling. ESH has a
>> designated storage cabinet. That's all. The vendor mounts the foil
>> on the Al ring. We are not doing any modifications here. The ring is
>> attached to the target stick inside the PRad chamber. We have places
>> for two foils. In the first run, we had 1-μm-thick carbon and
>> aluminium foils. They were damaged and need to be replaced.
>> 
>> -Eugene
>> 
>> -------------------------
>> 
>> From: Stepan Stepanyan <stepanya at jlab.org>
>> Sent: Wednesday, September 3, 2025 11:29
>> To: Eugene Pasyuk <pasyuk at jlab.org>
>> Cc: prad at jlab.org <prad at jlab.org>
>> Subject: Re: [PRad] beryllium target
>> 
>> Eugene,
>> 
>> Why are we going to this complication? Is this a necessary or a wish
>> list item?
>> 
>> Thanks,
>> Stepan
>> 
>> On Sep 3, 2025, at 10:51 AM, Eugene Pasyuk via PRad
>> <prad at jlab.org> wrote:
>> 
>> I checked with safety about the rules for Beryllium handling. There
>> are no significant complications. Those who will handle it must get
>> additional training, MED11.
>> Therefore, we can order Beryllium foil to use as an alternative to
>> carbon or aluminum as a point-like target for GEM efficiency
>> calibration.
>> The question is: what thickness do we want?
>> 
>> -Eugene
>> 
>> _______________________________________________
>> PRad mailing list
>> PRad at jlab.org
>> https://mailman.jlab.org/mailman/listinfo/prad
> 
>  _______________________________________________
> PRad mailing list
> PRad at jlab.org
> https://mailman.jlab.org/mailman/listinfo/prad
> _______________________________________________
> PRad mailing list
> PRad at jlab.org
> https://mailman.jlab.org/mailman/listinfo/prad