Run Plan for Kaon LT Luminosity Scan

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Revision as of 08:38, 15 October 2018 by Sjjooste (talk | contribs) (→‎Sweep 2)
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Goal

The electrons in the HMS will be used to monitor cryotarget boiling, while the positive polarity SHMS will be used to investigate the reliability of hadron tracking efficiencies at high rates. We will use three different targets:

  • standard 10cm LH2
  • C (z=1.5% RL) - maximum current 65uA
  • Al dummy - maximum current 40uA

Initial Setup

  1. Set PS1 and PS3 DAQ rates to 1.5kHz, to give a total rate to disk of about 3kHz.
  2. Increase EDTM trigger rate to 10kHz, to ensure that after prescaling there are 10k-100k EDTM events per run.
  3. Ensure the raster is on (2x2)

During scan

  1. Monitor number of EDTM events: to ensure 10k-100k events/run
  2. Try to get runs with minimum of beam trips: In particular, there might be a high number of trips due to the SHMS diffusor ion chambers at this small angle when running above 50uA. MCC can fix this by selectively changing the thresholds in the offending chambers. See here for more info.
  3. Be wary of DC HV trips in SHMS: we are at a small angle, for some of the higher currents we will have to switch off the HV for the SHMS DCs
  4. Use the highest current we can get: If MCC can't reach a current, we take data at the highest current that they can reach instead. This might mean we need to skip the highest luminosity settings.

Sweep 1

0. Preparation

Rotate HMS to 12.50 degrees, everything else is unchanged.

  1. PHMS = -3.266 GeV/c (unchanged)
  2. θHMS = 12.50 deg (NEW)
  3. PSHMS = 6.842 GeV/c (unchanged)
  4. θSHMS = 6.49 deg (unchanged)

1 - 70uA LH2

  1. LH2 target (unchanged)
  2. Request 70uA; run at highest current available if we can't reach 70uA (likely)
  3. If running at 70uA: switch OFF SHMS DCs: expecting ~1MHz SHMS singles rate which will trip the DCs
    1. Else: keep DCs ON and carefully monitor if running at lower current: ~58uA is the highest current we know we should be able to run without issues in this setting, but it is currently unknown at which exact current the DCs start to trip.
  4. Try to take a good 12min run with minimal trips

2 - 65uA C-1.5%

  1. Change target to C-1.5%
  2. Request 65uA; run at highest current available if we can't reach 65uA (likely)
  3. Ensure SHMS DCs are ON and carefully monitor: rate should be bit lower
    1. If tripping is an issue, turn SHMS DCs OFF
  4. Try to take a good 12min run with minimal trips

3 - 50uA C-1.5%

  1. Keep C-1.5% target (unchanged)
  2. Only if current for previous measurement was >50uA (common sense)
  3. Ensure SHMS DCs are ON
  4. Try to take a good 12min run with minimal trips

4 - 50uA LH2

  1. Change target to LH2
  2. Only if current for previous measurements was >50uA (common sense)
  3. Try to take a good 12min run with minimal trips

5 - 30uA measurements

  1. Keep LH2 target (unchanged)
    1. Try to take a good 12min run with minimal trips
  2. Change target to Al Dummy
    1. Try to take a good 12min run with minimal trips
  3. Change target to C-1.5%
    1. Try to take a good 12min run with minimal trips

Sweep 2

0. Preparation

Change HMS angle and momentum, and SHMS momentum:

  1. PHMS = -4.202 GeV/c (NEW, make sure go through MOL)
  2. θHMS = 14.91 deg (NEW)
  3. PSHMS = 6.053 GeV/c (NEW)
  4. θSHMS = 6.49 deg (unchanged)

1 - 70uA LH2

  1. Change target to LH2
  2. Request 70uA; run at highest current available if we can't reach 70uA (likely)
  3. If running above >=50uA: switch OFF SHMS DCs: expecting 1-1.4MHz SHMS singles rate which will trip the DCs
    1. Else: keep DCs ON and carefully monitor if running at lower current: ~40uA is the highest current we know we should be able to run without issues in this setting, but it is currently unknown at which exact current between 40-50uA the DCs start to trip.
  4. Try to take a good 12min run with minimal trips

2 - 65uA C-1.5%

  1. Change target to C-1.5%
  2. Request 65uA; run at highest current available if we can't reach 65uA (likely)
  3. Decide what to do with SHMS DCs: use sweep 1 as a guide to decide weather we can keep DCs on or not
    1. If tripping is an issue, turn SHMS DCs OFF
  4. Try to take a good 12min run with minimal trips

3 - 50uA C-1.5%

  1. Keep C-1.5% target (unchanged)
  2. Only if current for previous measurement was >50uA (common sense)
  3. Decide what to do with SHMS DCs: use previous measurement as a guide to decide weather we can keep DCs on or not
  4. Try to take a good 12min run with minimal trips

4 - 50uA LH2

  1. Change target to LH2
  2. Only if current for previous measurements was >50uA (common sense)
  3. Switch OFF SHMS DCs': expecting 1MHz SHMS singles rate which will trip the DCs
  4. Try to take a good 12min run with minimal trips

5 - 30uA measurements

  1. Change to LH2 target if needed
    1. Try to take a good 12min run with minimal trips
  2. Change target to Al Dummy
    1. Try to take a good 12min run with minimal trips
  3. Change target to C-1.5%
    1. Try to take a good 12min run with minimal trips
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