G2p optics
From Hall A Wiki
Contents
Summary of Optics Plan
Define the following jobs: A. Acceptance calibration, sieve out, rasters on and off (large C12, no LHe) B. Delta scan, (sieve in, C12, no LHe) C. Beam position scan (Sieve in, large C12, no LHe, 8 points on x,y axis and 4 additional points at corner) D. Pointing (Sieve in, CH2, need to refill LHe)
1. 0T @ 2.257:
Do A, move sieve in, do B and C(12 points), refill LHe do D. At the end take elastic NH3 data to check NH3 thickness. When finish: move sieve out; Ramp field up to 2.5T; Drain LHe
2. 2.5T, 90deg @ 2.257:
Do A, move sieve in, do B and C(12 points), refill LHe do D. When finish: Ramp field up to 2.5T; Drain LHe out
3. 5.01T, 6deg @ 2.257:
Do B and C(8 points), refill LHe do D.
4. 2.5T, 90deg @ 1.706:
Do A, move sieve in, do B and C(8 points), refill LHe do D. When finish: Rotate target field to 6 deg; Ramp up to 5.01T; Darin LHe out
5. 5.01T, 6deg @ 1.706 GeV:
Here is the optics plan for gep at 1.706 GeV:
P0=1.691
Sieve IN:
target config number of events or beam time
C12 Sieve IN, No rasters 2 x 1M (10 minutes)
C12 Sieve IN, Both rasters 2 x 1M (10 min)
NH3 Sieve IN, Both rasters 3 x 7M (about 1 hours, which will give
about 400 events when cut to 1x1 beam size)
**Escorted access to move sieve out (30 min)
C12 Sieve out, both rasters 30 minutes(about 10 M events for each
arm, good for dilution)
In total 2.5 ABU, 3 hours were allocated.
6. 5.01T, 90deg @ 2.257:
Do A, move sieve in, do B and C(8 points), refill LHe do D. When finish: Turn off target field; Drain LHe, move sieve out.
7. 0T @ 1.159:
Do A, move sieve in, do B and C(8 points), refill LHe do D. At the end take elastic NH3 data to check NH3 thickness. When finish: move sieve out; Ramp field up to 2.5T; Drain LHe out
8. 2.5T, 90deg @ 1.159:
Do A, move sieve in, do B and C(8 points), refill LHe do D. When finish: Ramp field up to 5.01T; Drain LHe out Here is the optics plan for 1.1GeV with 2.5T at 90 degrees target field. Before doing optics, beam center and slow raster size have to be determined. No LHe, LHRS starts at -4% and right HRS start at -3.5%: 1. Delta scan: C12, sieve in , no raster (4 hours) Left HRS: -4%, -3%, -2%, -1%, 0%, 1%, 2%, 3%, 4% Right HRS: -3.5% -2%, 0%, 2%, 3.5% NOTE: if running out of time, we will skip 3.5% in right arm and 1%, 3% at left arm. This can save about 1 hours. **Ramp dipoles back to 0% when finish. (40 minutes) 2. Beam position scan: C12, delta=0; sieve in, slow raster only, (40 minutes) Config the slow raster to jump in the following way: 1)between (x=-5, y=-5) and (5,5) 2)between x=0, y=+/-5 3)between x=+/-5, y=0 3. Acceptance calibration, part 1: C12, sieve in, delta=0 (10 minutes) 1) both rasters on 4. Pointing: CH2, sieve in ,delta=0, no rasters (30 minutes) Take data till the H peak of a normal sieve hole can be fit. **Escorted access to move sieve out when finish (30 minutes) 5. Acceptance calibration, part2: C12, sieve out, delta=0 (20 minutes) 1) no rasters 2) both rasters Estimated time: 7 hours At the end of the optics, refill LHe, change to the 1st production point, start dilution runs then polarize NH3 target.
9. 5.01T, 6deg @ 1.159:
Here is the optics plan for gep at 1.15765 GeV beam energy:
P0=1.1571
T1_rate=5kHz on 40-mil-C12 target, with 50 nA 1.15765 GeV beam, sieve in, No LHe
Sieve IN,
If rasters are used, the fast raster is 2x2 and slow raster is 2 cm (or same as production runs):
target configuration number of events or beam time
C12 Sieve IN, No rasters 2 x 1M (10 minutes)
C12 Sieve IN, Both rasters 2 x 1M (10 minutes)
NH3 Sieve IN, Both rasters 3 x 7M (about 70 minutes, which will give
about 400 events when cut to 1x1 beam size)
**Escorted access to move sieve out (30 min)
C12 Sieve out, both rasters 30 minutes(about 10 M events for each
arm, good for dilution)
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Estimated time= 3 hours.
links
- Overall G2P|GEP optics plan
- 2.253GeV_0T_optics_runplan
- 2.253GeV_2.5T_90deg_optics_runplan
- 2.253GeV_5.0T_6deg_optics_runplan
With new right septum
For commissioning:
