Drift Chamber Gas System

HallD Drift Chamber Gas system

Both the Central Drift Chambers (CDC) and the Forward Drift Chambers (FDC) use an Argon/CO2 gas mixture for operation with a very small addtion of isopropanol to prevent chamber aging. The gas mixing is done with BROOKS mass flow controllers (MFC)of type 5850S powered and controlled by the BROOKS 0254 controller box.

Pin IN/OUT translation table for MFC and BOX:

  MFC   Box      MFC point of view
  ----------------------------------------------
   1     6      Setpoint Return
   2    10      0(1)-5 Vdc Flow signal output
   3    --      
   4     2      0(4)-20 mA Flow signal output
   5    13      +15 Vdc to +28 Vdc Power supply
   6    14      -15 Vdc Power supply (if required)
   7     3      0(4)-20 mA Setpoint input (+)
   8     5      0(1)-5 Vdc Setpoint input (+)
   9    12      Power supply common
  10     8      Flow signal output common
  11     4      +5 Vdc ref. output
  12     7      Valve override input
  13    --       
  14    --      Optional RS232C-RxD or RS485-A-
  15    15      ----