G2p optics

From Hall A Wiki
Revision as of 01:18, 3 May 2012 by Mhuang (Talk | contribs) (7. 5T 0deg @ 2.254 GeV:)

Jump to: navigation, search

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. 5T 0deg @ 2.254 GeV:

Here is the optics plan for 2.254GeV with 5T and 0 deg target field.
Before doing optics, beam center and slow raster size have to be determined. 
0. With LHe in, C12, sieve in , no raster  
2 runs (2Mx2) (double statistics)
Drain out LHe, LHRS starts at 0% and right HRS start at 4%:

1. Delta scan:  C12, sieve in , no raster  (3 hours)
Left HRS: -4%, -3%, -2%, -1%, 0%, 1%, 2%, 3%, 4%
Right HRS: 4% (Right septum I<=920A, so can only go to 4%.)
(-4%, -1% and +3% can be ignored if running out of time) 
NOTE: if possible, do 3% for right arm, which is 930A.
Left HRS: move target to CH2, do pointing at -2%, 0%, 2% (2Mx2 for each setting)
 
**Ramp left dipoles back to 0% when finish. (10 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) only fast raster on (1Mx2)
2) both rasters on (1Mx2)

4. (done with delta scan, 3 points)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) (1Mx2 each)
5. Acceptance calibration, part2:  C12, sieve out, delta=0 (20 minutes)
1) no rasters
Move to CH2 to do a run for pointing cross check
2) only fast raster
3) both rasters


Estimated time: 6 hours

At the end of the optics, refill LHe, change to the 1st production point,
start dilution runs then polarize NH3 target.

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)  
|
Estimated time= 3 hours.


links


With new right septum


For commissioning: