Left Arm Checks

In the process of editing and updating this page. Please contact Juliette Mammei crowder@jlab.org with questions or suggestions.

PREX Main<< Information for Shift Takers<<Shift Checklist

Figure 1: Checking the fields and momenta of the LHRS magnets

Figure 2: Checking the LHRS regulator status

Figure 3: -

Figure 4: -

Left Arm momentum (GeV)
- The blue box called P0 SET (0.00000 GeV/c in Figure 1)

Left Arm Q1, Q2, D, Q3 regulators on (yes/no?)
- Click on the small blue square next to P0 SET (GeV/c) (see Figure 2)
- Regulator status for each magnet is indicated by the depressed button (all regulators are off in Figure 2)
- Check the whiteboard for intended settings

Left Arm cryo flow level OK (Green)?
- He > 60% (Ignore Nitrogen)
- In the column labelled L(%) (100.2, 90.3, and 89.3 in Figure 1)

Left Arm NMR OK? Yes/No
- The NMR field readback is indicated in the "D-N" row of the GUI
- The NMR meter is useful only at > ~GeV set points, so if the magnets are too low then the NMR readback will be useless and fluctuating wildly (in which case the Gauss meter readback is useful, indicated in the "D-G" row)
- The NMR read-back quality can also be determined by looking at the Oscilloscopes in CH main room rack CH01A02 (above the adaq2 terminal). If the NMR is locked then the triangle wave and NMR readback will be synced and locked onto eachother in both scopes.

Are the magnets properly meeting their setpoints (are the read-back values within 0.5% of the setpoints?)
- Check the setpoints and readbacks by clicking on the I(A) menu button and looking at each magnet's GUI independently
- On the bottom left in the black box called BOX CONTROLS are the Setpoint (Amps) and the ReadBack (Amps)
  - Be careful , as you are able to change the settings from within these GUIs.
- Also, all magnets should be in negative polarity for Prex/Crex

Left VDC gas flow on (top/bottom)?
- Indicated by Orange "Gas Flow" panel in Hall A General Tools screen T_VDC/B_VDC l/h readbacks

Left VDC HV on (top/bottom)?
- See VDC HV GUI for more information
- Look at the kV values in the VDC HV section of the Hall A Tools (Figure 3)

VDC thresholds (yes/no?)
- See Hall A General Tools bottom right corner (Figure 4)
- All 4 set points and readback values should be 3.0 V

Have you checked the quality of the most recent online plots for the Left ARM counting mode DAQ (if a run was taken during your shift)?

Next in checklist >> Right Arm Checks

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