Difference between revisions of "Tune Photon Beam and collect data for initial detector checkout"

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##* <span style="color:#ff00ff">Procedure to check rates (Mark Dalton)</span>
 
##* <span style="color:#ff00ff">Procedure to check rates (Mark Dalton)</span>
 
## Turn Start Counter detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 4h, including 100% contingency) <math>\Box</math>
 
## Turn Start Counter detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 4h, including 100% contingency) <math>\Box</math>
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##* [https://hdops.jlab.org/wiki/index.php/Start_Counter_Commissioning Procedure for turning on Start Counter]
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##* [[Start_Counter_Commissioning|Procedure for turning on Start Counter]]
 
##* System expert: Eric Pooser/Mark Ito
 
##* System expert: Eric Pooser/Mark Ito
 
##* [https://hdops.jlab.org/wiki/index.php/Howto_read_ST_scallers Procedure to check rates]
 
##* [https://hdops.jlab.org/wiki/index.php/Howto_read_ST_scallers Procedure to check rates]

Revision as of 15:19, 24 October 2014

Tune Photon Beam

  • Goal: Tune the photon beam to go through the collimator, the experimental target area, and into the photon beam dump.
  • Expected Schedule:
    • See start dates in the run coordination meeting pages here. The initial photon beam and detector checkout is then expected to last 4 days.
  • Responsibility: HallD, Accelerator, RadCon.
  • Priority: Most activities are High, but includes Moderate and Low priority activities.
  • Prerequisites:
  1. Tagger hall equipment remain removed. ☑
  2. Hall D controlled quadrupole MQPAD00 remained turned off. \Box
    • Responsibility: MCC
  3. Hall D: Detectors turned off. Exceptions: Profiler, possible BCAL, outer rings of the FCAL \Box
  4. Monitoring available in counting room:
  5. Scaler acquisition operational for rate azimuthal asymmetry monitoring and initial detector study. \Box (Sergey Furletov, Mark Dalton)
  6. 1.5 µm Al (1.7·10-5 R.L.) radiator in.
  7. Collimator:
  8. Upstream profiler installed in the Collimator Cave, surveyed in order to find the position of the nominal beam center ☑
  9. Second profiler installed in front of photon beam dump, surveyed. ☑
  10. Active Collimator operational. ☑
    • System expert: Alex Barnes, Richards Jones
  11. Pair spectrometer field on, converter retracted. \Box
  12. Solenoid tested at 1200A (just prior to closing the hall). FDC surveyed with Solenoid on at 1200A. Solenoid will then stay on at quench-safe current ~300A.
    • System expert: Yi Qiang \Box
    • Procedure for setting the Solenoid current: Call Yi Qiang (primary, office: 269-7237, cell: 358-2146) or George Biallas (alternate, office: 269-7535, cell: 813-1179)
    • Procedure for monitoring the Solenoid current
  13. No target in place (air and material along the beamline makes a few R.L.). ☑
  14. The noise in the beam profilers was measured in the absence of electron beam. \Box
  • The ATLis corresponding to the runplan below can be found here

Activities

  • First period: Initial photon beam and detector checkout)
  1. (High) Produce acceptable photon beam. (Time estimate 4h including 100% contingency)
    1. Re-establish the CW electron beam on 1.5 µm Al (1.7·10-5 R.L.) radiator, with 50 nA electron beam centered in the Tagger Dump and photon beam centered on the upstream profiler (Accelerator/Hall D) (time estimate: 1h) \Box
      1. Verify that e- beam is acceptable, that is:
        1. beam width is fine (10-2 wings)
        2. electron beam position on the Tagger Dump viewer is good and photon beam centered on the upstream profiler.
        • Good rate expected in the profiler: 750 kHz. (Rate in one central fiber: 34kHz). Noise rate from backsplash is estimated to be similar.
        • System expert: Hovanes Egyian
        • Table of beam characteristics
      2. Ion chamber calibration (Time estimate 2h including 100% contingency)
    2. Retract the 1.7·10-5 R.L. radiator \Box (time estimate: 10 min) \Box . Measure the signal in the beam profiler in the absence of amorphous radiator (time estimate: 30min). Compare with previous measurement to assess possible e- beam halo scrapping. \Box . Re-insert the 1.7·10-5 R.L. radiator \Box (time estimate: 10 min) \Box
    3. Check the radiation levels in the Tagger Hall and the Collimator Cave \Box (time estimate: 10 min) \Box
  2. (High) Tune photon beam at the primary collimator location. (Time estimate 10h including 100% contingency)
    1. Using the upstream Profiler find the beam center position with respect to the nominal position (time estimate: 4h) \Box
    2. Adjust photon beam position while keeping e- beam centered on tagger dump (Time estimate: 30min). Obtain a first determination of the accelerator scale.
      • Ask MCC to move the beam to the nominal position, using the last e- beam line corrector. \Box
      • Calibrate the accelerator scale for x and y. That is, find the relation between the corrector currents and beam position at the profiler location. Obtain this information from MCC and log it in the Electronic logbook. This provides a rough accelerator scale. The fine one will be provided by the Active Collimator. \Box
      1. Monitor that the electron beam position at the Tagger dump remains acceptable \Box
      2. Keep monitoring radiation levels in the Tagger Hall and the Collimator Cave \Box
    3. Insert 5mm collimator in beam position.
    4. Check the photon beam position at the photon Dump using the second Beam Profiler \Box
    5. Move the collimator 5 mm hole in X, ±30 mm around the center in order to calibrate the Active Collimator X-response. Use 5mm step size. Leave the collimator in the nominal position (0.5 mm hole at the nominal center) . Meanwhile, monitor the Pair Spectrometer Rate (time estimate: 10min/step -> 2h) \Box
    6. (Moderate) If the Active Collimator data provides a better position accuracy - move the beam in X accordingly (time estimate: 10min) \Box
    7. (High) Ask MCC to move the beam in X ±10 mm around nominal beam position at collimator. Use 2mm step size. Verify that the beam X-position from the Active Collimator matches (time estimate: 10min/step -> 1h40) \Box
    8. (High) Ask MCC to move the beam in Y ±10 mm around nominal beam position at collimator. Use 2mm step size. calibrate the Active Collimator response (time estimate: 10min/step -> 1h40) \Box
    9. (Moderate) If the Active Collimator data provides a better position accuracy - move the beam in Y accordingly (time estimate: 10min)\Box
  3. (High) measure the beam position with the Pair Spectrometer's harp (time estimate: 2h, including 100% contigency)
    1. Verify that the pair spectrometer magnet is on at nominal field (1.8T). (time estimate: parasitic). \Box
    2. Turn on the low-granularity PS counters \Box , DAQ \Box and controls \Box (time estimate: parasitic).
    3. Install a PS foil converter (time estimate: 5 min)
    4. Measure the rate (time estimate: 30min) \Box
      • Expected rate: 110 Hz (coincidence. No significant noise expected); 430 Hz for one arm (without accounting for noise)
    5. Using the PS wire scanner, measure the position of the beam spot at the converter (time estimate: 20 min) \Box
      • Procedure: Call Hovanes. (For this first time use, the expert is necessary to interpret the data)
    6. (High) Insert a PS foil converter, turn the PS detectors on and start taking data - keep the PS running (time estimate: 5 min, then parasitic) \Box
  4. (High) Orbit Lock commissioning (Time estimate 1h including 100% contingency)
  5. (Moderate) Fast Feedback commissioning (Time estimate 4h including 100% contingency)
  6. (High) Verify target/Start Counter alignment & Initial GlueX detector checkout
    1. Ramp down the solenoid to 0 Gauss in order to allow beam line radiological survey (the magnetic field may disturb the survey instruments).
    2. As soon as the survey is done, set the solenoid current to 1000 A (time estimate: 2 hours, but done during steps 3 and 4) \Box
      • System expert: Yi Qiang
      • Procedure for setting the Solenoid current: Call Yi Qiang (primary, office: 269-7237, cell: 358-2146) or George Biallas (alternate, office: 269-7535, cell: 813-1179)
      • Procedure for monitoring the Solenoid current
    3. Meanwhile, insert the 1cm CH2 target (1.2% RL).
    4. (High) Close the Hall, restore the beam, turn on the detectors one by one:
    5. Turn BCAL detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 1h, including 100% contingency)
    6. Turn Start Counter detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 4h, including 100% contingency) \Box
    7. Turn FCAL detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 1h, including 100% contingency) \Box
    8. Adjust target/SC alignment (time estimate: 2h, including 100% contingency) .
      1. Check effect of +/-1cm collimator x-translation on Start Counter and FCAL rates. (0.5 cm steps, 15 min/steps -> 1h, including 100% contingency)
      2. Minimize possible large asymmetries by adjusting the collimator or target assembly (Assume 1h).
    9. Turn TOF detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 4h, including 100% contingency) \Box
    10. Turn CDC detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 2h, including 100% contingency) \Box
      • System expert: Benedikt Zihlmann.
      1. Some HV card on the inner-most layer are powered by Verne-Keibler HV supplies. Current limit is set to 0.1 muA and a video camera visible in the control room watches the currents. The voltages are set to nominal CDC levels (2100V).
      2. If currents are stable and under 500nA, then the remaining HV cards on the CDC can be turned on. These are connected to the normal CAEN supplies. Verify that no channels trip during this process.
    11. Turn FDC detector on slowly. Check scaler rates. Monitor the rates and background levels. (time estimate: 2h, including 100% contingency) \Box
    12. Trigger settings for a combination of BCAL and FCAL signals, adjust the timings and the thresholds. Estimate: 8h, including 100% contingency).
      • System expert: Alexander Somov
    13. Take data for all the subsystems (time estimate: 8 h) \Box

End Initial photon beam and detector checkout

Next step: One week pause in running for Tagger electronic reinstallation and data analysis.

Back to main Fall14 commissioning page

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