TOFp System Procedure:
pVPD High Voltage On or Off


   Description:
This is the procedure to turn on or off the High Voltage applied to the pVPD Detectors. The pVPD HV is to be turned off when there is the possibility of stray beams in the WAH, and it is to be turned on during normal running. This HV is provided by the LeCroy 1440 power supply (Rack 1B4, South) that also provides the CTB HV. Numbering as in the LeCroy 1440 from 0-15 for slots, and 0-15 for channels in each slot, the pVPD channels are: (slot,channel) = (3,15), (4,15), (5,15), (6,15), (7,15), and (8,15).
   Related Documentation:
  1. TOFp Glossary
   Requirements:
  1. Access to STAR Control Room.
  2. STAR Shift Crew Training.
  3. Approval of Shift Leader.
   Procedure:
  1. Sit in front of the Trigger group computer that runs the CTB High Voltage GUI.
  2. Locate the main page of this GUI, and on the extreme left side of that page locate the two buttons: "pVPD HV On" and "pVPD HV Off"

    3. pVPD HV OFF

  3. Click on the botton "pVPD HV Off".

    4. pVPD HV ON

  4. Click on the botton "pVPD HV On".
   Testing:
  1. Use the GUI to view each of the individual slot display pages separately. pVPD channels exist in slots 3 through 8 inclusive.
  2. Look at the GUI information for the channel displayed lowest on each of these pages. This is channel 15 on each page.
  3. In all cases, the RGB marker should be GREEN, indicating the 1440 is providing the proper voltage within preset limits.
   Completion:
  1. Contact TOFp Control with any end-of-procedure comments that are necessary. Was this procedure successful? Is this documenation understandable and complete?