Beamline

HARP

Initial BPM/Raster checks/Beam centering [3-4 hours]

1. First MCC centers the beam on the beam dump using the ion chambers.
2. Establish CW beam.
3. Note that we will NOT be going through the Compton chicane.
4. With no more than 5 μA of stable beam find the center of the target using the steps below:
   1. For each step, make sure to record both the rates from the right HRS and the BPM positions at BPMA and BPMD.
   2. Move the target to the Empty 1 position.
   3. Before asking for beam, check the right HRS (T1 trigger) rates. Record this rate in the HALOG.
   4. Run beam with the target in the Empty 1 position at 5 μA, while checking the right HRS (T1 trigger) rates. Record the rate and the beam positions.
      
   5. Move the target to the Carbon hole position. Then have MCC restore beam at 5 μA with a 2x2 mm² raster.
      - Check the rate in the right RHRS (T1 trigger). Record this rate.
      - If you can see a difference in rates between the foil and no foil, then continue. Otherwise contact the run coordinator.
      
   6. Use the spot++ tool on both L-HRS and R-HRS (see Raster calibration, spot++)
   7. Verify that the raster is approximately centered on the Carbon hole target. If it is not, ask MCC to move the beam position in x and y until the hole is roughly centered on the raster image.
      Do not increase the raster size. If you cannot find the hole with the raster ON, please contact the run coordinator (Contact information is on the white board).
   8. After the raster is centered on the hole, have MCC turn off the raster. Since the hole in the Carbon foil is 2 mm in diameter, and the beam spot is much smaller than this, the rates should drop to the rates with the Empty target.
      
   9. Now move to the "Raster Target". Ask MCC for 5 μA of beam with a 2x2 mm² raster. If the beam is centered, the rates should match the rates of the empty target.
   10. If you notice excess rate, then slowly move the beam position until the rates are the same as those with the empty target.
   11. After beam centering, update the nominal beam positions on the white board.
   12. Make sure you make a detailed log entry with the results of the position scan.
5. Superharp Scan with Raster off to check if they are working and provide signals:
   1. Scan the two superharps (IHA1H04A and IHA1H04B) near the target with raster off. Make sure you obtain two pictures including the three wires for each harp. You should post these images to the HALOG.
   2. Instructions are available on how to do the scans, but make sure you do them for IHA1H04A and IHA1H04B.
   3. Make sure the three wires are clearly visible and have reasonable resolution: ~400-500 μm.
   4. If the harp scans are successful, then proceed with the bullseye scan below.

BPM Calibrations (Bullseye Scan) [1-2 hours]

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. 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 analysis the bulls eye scan.

Superharp Scan with Raster off/on

1. Scan the two superharps near the target with raster off. Obtain two pictures including the three wires for each harp.
2. Make sure the three wires are clearly visible and have reasonable resolution: ~ 100-200 μm.
3. Repeat with raster on. In this case, you may not see the wires clearly.
4. Make sure to post the results in the Hall A electronic logbook or Halog.

BCM Calibrations [2 hours]

1. Warn MCC a few hours beforehand.
2. 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.
3. 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.
4. Also start a HRS run to record the scalers during the calibration procedure.
5. It is useful to have someone over in MCC to help coordinate the calibration with them.
6. 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]

1. The procedure will be conducted by Doug Higinbotham in coordination with MCC.
2. Notify Doug and MCC a few hours beforehand to make sure they are ready and available.