Difference between revisions of "BPM"
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Pedestal run: | Pedestal run: | ||
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| − | + | [https://wiki.jlab.org/tegwiki/images/5/58/BPM_cal_02162019.pdf Before and After images for BPM pos] | |
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| − | + | == BPM Calibrations (Bullseye Scan) [1-2 hours]== | |
Latest revision as of 14:36, 18 February 2019
Contents
How to perform a bulls eye scan:
1. You need unrastered beam:
- use single foil target.
- set PS8=100, run both arms
2. Ask MCC to steer the beam to the nominal center of the target.
3. Wait until beam is stable and have MCC perform a harp scan for the two superharps near the target (1H04A and 1H04B) and take a CODA run for both the left and right spectrometers during the same time. Start the coda run first before asking MCC. Request MCC to make an ELOG entry with the Harp results, you should see all three harp wires. Record ELOG entry numbers and timestamps of both harpscans.
4. Ask MCC then to steer the beam to positions around the nominal center:
- cover at least the area the raster will cover: (2,2), (2,-2), (-2,-2), (-2,2), (3,3), (-3,-3), and repeat (0,0)
- These exact locations are just suggestions. The important thing is to cover the area of the raster.
- repeat harp and CODA runs for each position
5. Record Harp scan run numbers and corresponding CODA run number for each beam position. As an example, see HALOG # 3324009.
6. Make a record of the harp scans and CODA runs in the HALOG.
How to analyze the bulls eye scan:
- detailed instructions can be found at the Analyzing BPMs website. - the shift crew is not expected to analyze the bulls eye scan.
BPM pedestal run (20 minutes)
1. Ask MCC to set iocse10 to Forced gain = 0.
- Can be located at /cs/opshome/edm/bpm/diag_see/IPM_E_GainCntrl.edl
2. Take CODA run for both Right and Left arms.
- Use only clock triggers. T8=100
- Need about 100k events.
3. Ask MCC to set iocse10 to auto gain.
- Can be located at /cs/opshome/edm/bpm/diag_see/IPM_E_GainCntrl.edl
Calibration
Pedestal run: For both arms 4072
Harp scan 4065,4066,4667,4069,4070,4071
Before and After images for BPM pos
