R-HRS Optics Calibration Procedure with Positive Polarity and PREX Target Only
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Version 2.0. Initiated by Jin Huang; Commented by Yi Qiang, Vincent Sulkosky, Natalia Toro
Contents |
General
This is preliminary procedure for R-HRS initial optics commisioning for following conditions:
- No one pass beam provided. Have to commision with 2 pass beam
- No APEX optics target. Have to use preinstalled PREX target, which misses 1~2 carbon foils.
- PID detector in R-HRS is commissioned
Within these limits, there will be no calibration on R-HRS for dp. ph th calibration is probable, depending on clear position sieve parttern. Vz calibration is straight forward with pi+
With correction magnet, beam position/direction on target will pose a serious problem to optics calibration. At calibration, we will need to know good beam x, y at each foil. Therefore both position and slope is important to know. Therefore I suggest, if possible, keep correction magnet at constant current within this study. Once calibration is done, change in beam direction will not affect quality of optics reconstruction (leading correction is 2nd order for th, ph, dp; 1st order for vz). New ideas are welcome.
Time Cost
- Approximate beam time is 4-5 hour, with in which, 2~3 hour is optional
- Approximate configuration change time is 5 hour
- 1 control access to remove sieve
Assumed initial condition
Beam Energy: 2.262 GeV Septum angle: 5 Degrees HRS and septum polarity: APEX configuration, correction magnets working. Sieve-slit: any (prefer IN) Raster: any (prefer OFF) Target: any (prefer Empty) Left HRS Momentum: any (prefer 1.131GeV/c) Right HRS Magnets: any (prefer 1.131GeV/c) R-HRS in positive polarity L-HRS in Negative polarity Yi's Hypernuclear 6 degree super conducting optics database for both arms as start software point. PID detectors in R-HRS commissioned!!
Run plan
0) General Procedure:
a) Q2/Q3 need cycling. How to Cycle Quads Q2 and Q3:
* Turn off the regulator (click GeV/c button on magnets screen to the things to click)
* Q2 is presently limited to 1000A. Here is how to cycle (halog 312896): Ramp up to 1000A and back to zero. Repeat this a 2nd time, then go to the desired setting.
* For Q3 the cycling procedure is normal: ramp to 1400A, then go back to the desired setting.
* Don't cycle Q1.
* Turn on regulator
b) We take this batch of optics data by pre-scaling to 500kHz LHRS s2m trigger (T1?) and 1500kHz RHRS s2m trigger (T??) + all coincidence trigger(T??). DAQ dead time is not important.
c) Beam current on optics target is 2uA (Call MCC and ask for max current on optics. If 2uA is above their limit, use max they can provide.), Ta target is 2uA.
d) Replay each run to demonstrate
* high VDC efficiency.
* Check s2m, gac Cer, pion rejector is working and calibrated.
* Check Trigger type distribution is as described (b)
e) call MCC before change momentum on septum (or PREX P0 SET on hall A tools)
1) Rotate the both sieve slits to the IN position.
2) p->1.1310GeV/c for both HRS. Follow the Q2 and Q3 cycling procedure discussed above, (suggested to do so event HRSs are already 1.1310GeV/c. This prevent missing cycling occurred before).
- Notice : change momentum through PREX P0 setting on Hall A tool. NOT momentum setting for each HRS! Please also Halog Hall A tool for each change. Wait for all magnets stable before taking data
3) Tune beam through correction magnets and septum to beam dump with HRS momentum = 1.1310
4) Must: Perform delta scan around 1131 MeV/c with Sieve IN. Take data with the optics target and with the Ta foil.
- Main purpose for this study is for this study is to identify Sieve with positron on R-RHS. Also trying test angular reconstruction on L-HRS with new septrum polarity (probably not working due to elastic electron punch through). Momentum scan is to search for better kinematics region for position samples. Since there is no elastic peak to show clear sieve, more data are needed to perform regional cuts on VDC. Raster-ON-runs are for raster correction check.
(a) 0% Momentum = 1.131 GeV/c Raster OFF; Take 4 runs with 1000k each (b) 0% Momentum = 1.131 GeV/c Raster ON; Take 2 runs with 500k each (d) -10% Momentum = 1.0179 GeV/c Raster OFF; Take 4 runs with 1000k each (Optional, Call RC to know) (e) -10% Momentum = 1.0179 GeV/c Raster ON; Take 2 runs with 500k each (Optional, Call RC to know) (d) -20% Momentum = 0.9048 GeV/c Raster OFF; Take 4 runs with 1000k each (Optional, Call RC to know) (e) -20% Momentum = 0.9048 GeV/c Raster ON; Take 2 runs with 500k each (Optional, Call RC to know)
- Notice : Change momentum through PREX P0 setting on Hall A tool. NOT momentum setting for each HRS! Please also Halog Hall A tool for each change. Wait for all magnets stable before taking data
- Raster ON = no less than 2x2mm on spot++; Raster OFF = ask MCC to turn off raster and verify on raster oscilloscope.
5) Take an access and rotate the sieve slits to the OUT position.
6) p->1.131GeV/c for both HRS. Follow the Q2 and Q3 cycling procedure discussed above.
- Notice : change momentum through PREX P0 setting on Hall A tool. NOT momentum setting for each HRS! Please also Halog Hall A tool for each change. Wait for all magnets stable before taking data
7) Must: p0=1.131GeV/c Sieve out runs. Take data with the optics target and with the Ta foil.
- Main purpose for this study is for establishing vertex reconstruction for both arm with pions. It will be main vertex data for R-HRS, also test for vz shift on L-HRS at new septum configuration. Since there is no elastic peak to show clear sieve, more data are needed to perform regional cuts on VDC. Raster on runs are for raster correction check.
(a) 0% Momentum = 1.131 GeV/c ; Take 4 runs with 1000k each (b) 0% Momentum = 1.131 GeV/c ; Raster ON; Take 2 runs with 500k each
- Raster ON = no less than 2x2mm on spot++; Raster OFF = ask MCC to turn off raster and verify on raster oscilloscope.
8) Optional: Repeatability test. Recycle Q2 and Q3 and set back to same momentum. Take data with the optics target and with the Ta foil.
- Main purpose for this study is for demonstrate vertex reconstruction stability as a demonstration of optics stability for magnet cycling, scaling and rate
(a) 0% Momentum = 1.131 GeV/c ; Raster OFF; Take 2 runs with 500k each (a.1)0% Momentum = 1.131 GeV/c ; 50uA on Ta target, 2min limit. Raster OFF; Take 2 runs with 500k each (b) -10% Momentum = 1.0179 GeV/c ; Raster OFF; Take 2 runs with 500k each
- Notice : change momentum through PREX P0 setting on Hall A tool. NOT momentum setting for each HRS! Please also Halog Hall A tool for each change. Wait for all magnets stable before taking data
