Difference between revisions of "XEM specific shift instructions"

Latest revision as of 00:18, 4 October 2022

!!! NEW !!! User set EDTM

The prescale_GUI will not automatically scale the EDTM as it had for previous COIN experiments. Setting the EDTM is a critical step! Without setting the EDTM properly, the dead-time will not be measured correctly.

Setting the SHMS EDTM

• In single-arm mode, the SHMS EDTM needs to be set each time the pre-scale changes
• A printout has been added to the HCDESK4 computer for your information
• The goal is to obtain 50Hz of EDTM AFTER PRESCALE

Instructions for setting the SHMS EDTM:

1. Set the pre-scales for the desired trigger(s) and hit save on the prescale gui
   
   • Important: Do NOT start the run yet, wait until the EDTM is set.
2. Navigate to the SHMS CODA VNC session (same window) and locate a terminal window (there should already be one open where coda is started from).
   • Or just open a new one.
     
3. Locate the printout at HCDESK4 that tells you what rate to set the EDTM to for each pre-scale value. Use the lowest prescale to set the rate if multiple triggers are used.
4. In the terminal, enter go_edtm set <EDTM rate from table>
5. Validate the EDTM by running go_edtm get
6. Remember to do this each time you change the pre-scale. This step is critical for the experiment.

Setting the HMS EDTM

• In single-arm mode, the HMS EDTM needs to be set each time the pre-scale changes
• A printout has been added to the HCDESK1 computer for your information
• The goal is to obtain 50Hz of EDTM rate AFTER PRESCALE
• HMS EDTM is set with the WaveTek function generator next to HCDESK1.

Instructions for setting the HMS EDTM:

1. Set the pre-scales for the desired trigger and hit save on the prescale gui
   
   • Important: Do NOT start the run yet, wait until the EDTM is set.
2. Locate the printout at HCDESK1 that tells you what rate to set the EDTM to for each pre-scale value.
   • Important: Use the lowest prescale to set the rate if multiple triggers are used.
3. Use the FIELD buttons at the top to navigate to the FREQ field.
4. Type the desired frequency and PRESS ENTER
   • Important: Not pressing enter will not set the new frequency
5. Validate the HMS EDTM by checking the prescale_gui on the wall. You should see hEDTM under the first Trigger menu.
6. Validate the SHMS EDTM has not changed from what was set by the target operator.
7. Remember to do this each time you change the pre-scale. This step is critical for the experiment.

Setting the COIN EDTM

• In coincidence mode, the COIN EDTM should be set to 10Hz as long as we are taking open trigger on pTRIG5 or pTRIG6.
• A printout has been added to the HCDESK4 computer for your information
• The goal is to obtain 10Hz of EDTM AFTER PRESCALE. The rate of coincidence is always low, so it 10Hz is enough rate.

cerMode 10 Running

These instructions are specific to the XEM experimental run, please read them carefully

During the XEM run, we want to read out the full Cerenkov waveform. As such, we want to take mode 10 information for all gas Cherenkov PMTs during every run.

• To ensure this is the case, please make sure that the cermode10 checkbox on the prescale GUI is enabled. This should appear as in the image below

Magnet cycling

[Aug 20, 2020] 
When ramping up the SHMS or HMS magnets, do it in steps to minimize the chance of a trip.  So, ramp to the same MOL current in the end, but get there in 3--4 steps.  There is no need to pause between steps, just watch the magnet screens and adjust the set current in 3--4 stages.  You can do multiple magnets at a time -- just watch them.
(This makes it easier for the lead-flow controllers to reach the needed flow and remain stable.)

• Make sure to follow the appropriate magnet cycling procedure for the HMS and SHMS magnets. The cycling procedure is particularly important when going to a HIGHER momentum setting on the spectrometer.
• The HMS dipole in particular takes a long time to settle. Be sure the NMR is locked and stable before starting to take data!
• When the SHMS is at 10 degrees or below, ask for beam off when cycling magnets.

Setting Spectrometer angles

• Make sure to record all angles to 0.005 degree using the marks on the floor (interpolate to nearest half-division).
• It should be possible to set the spectrometers to within 0.01 degree of the desired value without too much difficulty. At some places the floor is not completely flat and this may be a problem. If so, then set the angle to within 0.03 degree of what is requested, but make a clear record of the actual setting in the hclog.
• Make an elog entry with an image of the floor marker angles on the camera every time you do a rotation.

Beam Position

• We would like to control both the position and angle of the beam on target. Unless specified otherwise, please ensure that MCC puts the beam at the nominal position (written on the white board) for both the 3H07A and 3H07C BPMs.

Rates

• Single particle and coincidence rates have been estimated for all runs. Watch the scintillator rates (S1 and 3/4 planes) for each spectrometer for an indication of the particle rate through the wire chambers, and if actual rate is substantially (> 50%) higher than what is listed in the run plan, the RC should be warned.
• We want to keep the particle rate in each spectrometer below 750 kHz, and for some forward SHMS angle runs this will require the beam current to be significantly reduced from the nominal 70 μA value.
• For some low rate runs, it may be possible to use up to 100 μA beam with particle rates still below 350 kHz. Consult with the RC before requesting a higher beam current.
• The prescale values in the run plan are a guide. Adjust them to keep the singles data rate in each spectrometer between ∼100-150 Hz.
• If you change the prescalers, you must update and apply them in the GUI by clicking save before you start a new run

• Please be aware that the GUI sometimes "freezes" and does not update. Please check that it is still alive and corresponds to reality in terms of rates.
  • This issue is very common when prescales are updated in quick succession.
  • To check if this is an issue, examine the run-start screen and ensure the prescale values listed in the run description match the GUI and what is needed for the run.
• Please also be aware that the GUI sometimes miscalculates the EDTM scaler rate when the GUI is being changed and does not update properly.
  • To check if this has occured, examine the coda-flags file in the run-start hclog. Ensure both the desired and scaler EDTM rate are correct.
• If the GUI needs to be corrected due to an update error, first try reentering the values and saving again. If this does not resolve the issue, close and reopen the prescale GUI.
• All run times assume 100% running efficiency. Adjust the time for actual delivered beam time, and let the RC know if the efficiency drops below 60% for an extended period.

Analysis

• On a terminal, ssh cdaql1 for HMS or ssh cdaql2 for SHMS (HMS on HCDESK1 right monitor, SHMS On HCDESK4 right monitor)
• type go_analysis to setup the analysis environment and bring you to the correct directory
• Once 50k events are reached for a given run, type ./run_(s)hms.sh to run the 50k replay.
• Once the run is completed, type ./run_full_(s)hms.sh to run the full replay for that run.

Todo: If standard.kinematics is not updating, expert needs to restart the automatic database file.

Filling out the Runsheet

Detailed instructions on filling out the XEM runsheet

1. Run #
   • On CODA in Box Labeled "Run Number"
2. Start and Stop Times
   • On top bar of CODA under "Start Time" and "End Time"
3. Target
   • See the target GUI, or ask the Target Operator. If the TO doesn't know what target is being used, escort them from the premises.
4. Fid.Trk Eff (%)
   • This value can be found on the summary output document that pops up after the 50k Replay. If this has been closed, you can open it again using the text editor of your choice (nano, emacs, ...) by finding the summary_output_#####.txt in the ./MON_OUTPUT/(S)HMS/REPORT/ directory (Full Path: /net/cdaq/cdaql1data/cdaq/hallc-online-xem2022/MON_OUTPUT/(S)HMS/REPORT/). It is called E SING FID TRACK EFFIC.
5. EDTM Rate (k)
   • Ignore the (k). Just put down the EDTM Rate in Hz. See the EDTM section above for more information. To get the EDTM rate, type go_edtm get on a terminal in the CODA VNC session for SHMS, or look at the Wavetek Function Generator next to HCDESK1 for HMS.
6. Extrapolated # of Electrons (this run)
   • Once the 50k replay has finished, the script should print out "Electron Count:" near the bottom followed by a rough estimate of the number of good electrons detected in the 50k events. Extrapolate this number to determine approximately how many good electrons were in the entire run. Simply, take the total number of CODA events at the end of the run, divided by 50k, multiplied by the Electron Count found from the 50k replay.
7. Data OK or Junk
   • Self Explanatory
8. Beam Current
   • This can be found by looking at the live beam current plot on one of the large wall monitors.
9. PS#
   • Put down the prescale factors as found on the prescales gui.
10. CODA Events (k)
    • Once the run is finished, write down the number in the box labeled "Total Events" on CODA.
11. Comp. Live Time (%)
    • This value can be found on the summary output document that pops up after the 50k Replay. If this has been closed, you can open it again using the text editor of your choice (nano, emacs, ...) by finding the summary_output_#####.txt in the ./MON_OUTPUT/(S)HMS/REPORT/ directory (Full Path: /net/cdaq/cdaql1data/cdaq/hallc-online-xem2022/MON_OUTPUT/(S)HMS/REPORT/). It is called Pre-Scaled Ps# Computer Live Time. Use the live time corresponding to the trigger that was on for that run.
12. DAQ Rate (k)
    • During the run while at full current, record the Event Rate.
13. Extrapolated # of Electrons (this setting/targ)
    • If multiple runs are taken at the same target and setting, keep a running total of extrapolated number of electrons at that target and setting here.
14. 50k Replay Done
    • Check this off once the 50k replay has finished successfully, and you have verified that the plots look OK.