[Halla_running] Priorities for Hall A once beam is restored

[Ciprian Gal]

Hello everyone,

Thia and I put together the list of priorities and some details for the
studies that we discussed during the meeting today. The date for beam to be
restored is still very fluid but current estimates put it at the end of
next week. We will keep you updated once we have more details.

Priority for studies:

   1. Harps, BPM and raster calibration, maybe beam energy study at the end
(1 shift)
   2. GMp/DVCS combined optics studies of both spectrometers (2 days)
   3. Send beam through Compton chicane (1 shift)
   4. Compton and Moller polarimetry work interchangeably (3 days)
   5. SBS detector tests, can do during Compton polarimetry studies
   6. Ask for a second beam energy measurement**
   7. Check if accelerator can provide high intensity. If so then we can go to
Unser, BCM calibrations
   8. Another option if 6. is not possible is to ask for 5 pass for GMp
measurement

**background for Compton has to be taken into account

Study details:

   - Optics studies:
      - requires 10-15 muA
      - Carbon, optics target, sieve, H elastics
      - HRS-R can stay at 52 degrees, but needs a new survey (which can be done
at the end of the run)
   - Compton studies:
      - go through chicane
      - test backgrounds
      - check new thick Si detector
      - beam size needs to be 0.1-0.2 mm (they have not provided smaller than
0.5mm at high energy so far)
      - E locks on
   - Moller
      - tests needed to improve precision
      - with the current setup we should assign 2.5% systematic uncertainty
      - beam charge asymmetry with any whatever quality beam to
synchronize with
HRS (~30 minutes)
      - needs BPMs, E locks
   - SBS tests:
      - needs proton spectrometer and ECal at 20-30 degrees

Target:

The target will be He cooled to facilitate high currents on the optics
targets. No target operator is required to be available for this condition.
It will take ~2 shifts to liquify the H target, so must plan with target
group in advance for day shift time to do this. Once there's a liquid H
target, target operator shifts must be filled 24/7.

Cheers,
Ciprian

*************************************************
Ciprian Gal
Postdoctoral Researcher
University of Virginia, Va, USA
*************************************************
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