How to Check High Voltage for RICH

• • • After beam tuning up, please check HV for RICH.***

How to Check the High Voltage for RICH?

1. Click RICH Detector in Hall A Main Menu

2. Click the CAEN at the bottom of HALL-A RICH DETECTOR (HALLA_RICH.adl)

3. Click the Modules in Hall A Slow Controls (CAEN.adl)

4. Click Modules in Module 2(red character) crate1 (module.adl)

5. You can see the Vmon values is almost with the Vset values in Channel 16 and Channel 17, currently is 2200V and 200 V. If it is true, it means the HV for RICH is ok. Please just close all the windows. (chan16-31.adl)

6.If the Vmon Values is far away from the Vset values in Channel 16, Channel 17, it means the HV for RICH is tripped. and the Status will show red Tripped/

then you need to

7.you need to Click the bottom of the Click symbol on the left of Module 2 Controls Screen(chan16-31.adl),then in the new page (chan16-31C.adl) you need to

8. if ON is in position, but it cannot go back to normal HV, please click OFF first, then Click ON again, it will automatically increase the HV step by step till almost the current values 2200V for Channel 16, 200 V for Channel 17 in <<Hall A Slow Controls CAEN High Voltage Power Supply Readbacks>> Module 2 (chan16-31.adl).

9. then you go back to Crate 1 to Click "Clear ALL Alarms" button in CAEN.adl. The status become "Normal" in Channel 16 and Channel 17 in chan16-31.adl.

Now The HV for RICH is back to normal, you can close all the windows.

• • • Why need to Check HV for RICH

After there is no beam for some time, the MCC will send beam again, usually the beam need to be tuned up, during this time, HV for RICH will possibly easily trip.