Initial BPM/Raster checks/Beam centering
- First MCC centers the beam on the beam dump using the ion chambers.
- Ideally the beam should be able to pass cleanly through the Compton chicane. But this is not a requirement.
- Check the raster size using the spot++ tool. After the target boiling studies result, the final raster size for production data will be decided.
- Insert carbon hole target to center the beam position with respect to the hole. Setup the raster to 2*2 mm, use spot++ to check if the beam is centered around the hole. Move the beam if necessary.
Superharp Scan with Raster off/on
- Scan the two superharps near the target with raster off. Obtain two pictures including the three wires for each harp.
- Make sure the three wires are clearly visible and have reasonable resolution: ~ 100-200 μm.
- Repeat with raster on. In this case, you may not see the wires clearly.
- Make sure to post the results in the Hall A electronic logbook or Halog.
BPM Calibrations (Bullseye Scan)
How to perform a bulls eye scan:
1. You need unrastered beam:
- caution you should not do this with a target requiring rastered beam - use carbon, BeO, optics, or in the worst case empty instead
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 (1H03A and 1H03B) and take a coda run during the
same time. Start the coda run first before asking MCC. Request MCC to make an ELOG entry with the results, you should see all three harp wires. Record ELOG entry numbers.
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) and repeat (0,0) - repeat harp and coda runs for each position
5. Record Harp scan run numbers and corresponding CODA run number for each beam position.
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 analysis the bulls eye scan.
BCM Calibrations [2 hours]
- Warn MCC a few hours beforehand.
- The Hall A BCM and scalers need to be cross-calibrated to the Faraday cup and a BCM in the accelerator (OLO2) and the Hall A Unser.
- Before beginning the procedure, make sure the Hall A BCM logger is started, which will record the signals from all relevant BCM used during the calibration.
- Also start a HRS run to record the scalers during the calibration procedure.
- It is useful to have someone over in MCC to help coordinate the calibration with them.
- Take data on carbon target with I = 10, 20, 30, 40 50, 60, 70, 80, 90, 100 μA (or as high a current as available).
ARC Energy Measurement [? hours]
- The procedure will be conducted by Doug Higinbotham in coordination with MCC.
- Notify Doug and MCC a few hours beforehand to make sure they are ready and available.