Compton Doc Portal

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The following is intended as a DAQ, and detector guide for Compton experts. Shifters and other non-experts should only use this page for reference. Contact a Compton expert if making changes are necessary.

Compton Electron Detector

How to check the electron detector's position status

Compton HV GUI Guide

Finding the HV Controls

These controls are kept open in a vnc on adaqsc. Check there first

  1. Go to the HV GUI computer to the left of the SL station.
  2. Open workspace/desktop 3 on the machine.
  3. Look for a vnc window open to adaqsc:1
  4. The HV GUI should be open there.

If the VNC is Running but the HV GUI is not Open

  1. Open a terminal within the vnc
  2. Do cd ~/slowc/
  3. Enter ./hvs BEAMLINE/ to bring up the GUI.

The VNC isn't open!

  1. Open a terminal on the HV computer, workspace 3
  2. Enter vncviewer adaqsc:1 --shared --RemoteResize=0
  3. The password can be found in the place where passwords are found

The VNC Opens but the HV window is blank when I bring it up!

  1. Call compton expert

HV Channels

The HV GUI controls our main detector, our finger PMTs, and our background detectors. The channels and appropriate voltages are listed below:

The correct voltages for the finger PMTs are as follows:

Slot Channel HV
Side (V) Finger SL-6 CH-10 -950 V
Top (H) Finger SL-6 CH-11 -1000 V
PhDet - Full Gain SL-12 CH-11 -1612 V
PhDet - 90% Gain SL-12 CH-11 -1607 V
PhDet - 70% Gain SL-12 CH-11 -1592 V
PhDet - 50% Gain (Use this for CREX production!!!) SL-12 Ch-11 -1569 V

If the photon detector is off and you're not sure whether or not it should be on, please contact Adam immediately. It's better to know for sure than to risk damaging our PMT.

Table Scintillators

  1. In the same GUI above navigate to S.9.
  2. Ensure that channels 0, 1, 2, and 3 are set +1800 V.

The table scintillators are classified as follows:

Slot Channel HV
DS Top SL-9 CH-0 +1800 V
DS Bottom SL-9 CH-1 +1800 V
US BR SL-9 CH-2 +1800 V
US BL SL-9 CH-3 +1800 V

Photon Detector Table

Normal Operation

  1. From the slow controls in JMenu, open up EDM Hall A and JTabs Hall A.
  2. Navigate Hall A->Compton->Controls. Look for the calorimeter on the design, click the button select table.
  3. Adjust the table to the desired x and y position.


If the table gets stuck or unresponsive and errors won't disappear, follow these instructions to reset the table manually:

  1. Take the double suction cup pump next to the compton terminal.
  2. Use the pump to lift the tile adjacent to the wall in front of the compton terminal. If you are standing in front of the terminal, the correct tile should be the one beneath your left foot.
    1. Be cautious not to injure your hand when lifting the tile! The tile is very heavy and can cause serious injury if mishandled!
  3. Once the tile is removed from underneath pull out the brown box with switches on it.
    1. NOTE: There is another box under there labeled "kill switch." Do not touch this box unless absolutely necessary!
  4. Once you have the brown box, flip the switch labeled "On/Off." If the red LED does not light, don't worry, that LED is dying.
  5. Flick the switch labeled "up" to begin moving the table manually. After just a second the table should be moved enough to be responsive, so flick the switch back.
  6. Once the table controls are responsive again, flick the switch to "Off," put back the box, and replace the tile, being careful not to pinch your fingers.

Taking Special Runs

LED Pulser Run

This instruction guide assumes you know how to use CODA to start and stop runs.

  1. Before running CODA run command ComptonConfig from the compton machine.
  2. From the options available select "Pulser On, Pulser Trigger." Click "Apply" and then "Done."
    1. If possible use comptcam1 to verify that the pulser box is turned on. If you can't see the pulser box LED from the camera angle then skip this step.
    2. You should also look at the parameters set in ~/crl/PulserOn_TrigPulser.flags If the pulser flags look good then you can proceed. If not, edit the flags file to your liking.
  3. Starting the next run on CODA will start the pulser run.
  4. Start a run in CODA the pulser will be
  5. Start a run. The pulser will be on.

IP Scaler Channels

Channel # Descr
0 -Not Connected-
1 40 MHz Clock
2 BPM2A Y-
3 BPM2A Y+
4 BPM2A X-
5 BPM2A X+
6 BPM2B Y-
7 BPM2B Y+
8 BPM2B X-
9 BPM2B X+
10 HFinger (Top)
11 VFinger (Side)
12 CavPower
13 Trig (Low Thresh)
14 BCM
15 -Not Connected-

Run Scaler Channels

Channel # Descr
0 ComptonDSbg1
1 ComptonDSbg2
2 40 MHz Clock
3 40 MHz Clock
4 ComptonUSbg1
5 MPS Scaler
6 ComptonCentralRateHigh
7 ComptonCentralRate
8 -Not Connected-
9 -Not Connected-
10 HFinger (Top)
11 VFinger (Side)
12 PMT Trigger Rate
13 ComptonUSbg2
14 PMT mid thresh rate
15 -Not Connected-

Expert Links and Controls

Default Settings and Positions

In addition to the HV's listed above, we also have a visual center on the photon detector

Date X (mm) Y (mm) Centering Method
2019-06-17 70 33.5 Visual
2019-11-20 70 32.5 Visual
2020-01-16 72.75 30.7 Fingers

The jaws have their own positions as well:

Aperture (mm) y center (mm) Comment
1.50 -46.00 HOME position