COMPASS

Instruction for the shift crew

(Run 2002)

Check pressure in service pipes:

Verify that the input pressure (manometer in the distribution pannel) is well above the pressure at the individual pressure reducers which are connected to the pannel.
The value of the input pressure can vary due to several reasons:
- total amount of gas used
  (not only by COMPASS, there are partial other experiments connected to the CERN gas distribution network)
- weather condition ((change of temperature results in change of pressure depending on the flow in the pipe))
- amount of gas left in the bottles (in bld. 908)
  The distribution system in bld. 908 (should) keep the pressure constant by switching to a new bottle, well before the preassure reaches the value indicated at the input manometer. So, if the system is
  - not adjusted properly : a temporarily drop (Observe! Empty bottle notification schould occur.),
  or
  - malfuncioning: a permanent drop (Call expert!)
  of the pressure could occure.
THIS APPLIES FOR NEUTRAL AND FLAMMABLE GASES !

In particular the gases are:
- neutral gases:
  (gas mixing area, 3 green racks on the right hand side)
  - Ne, CF₄: supplied by bottles in bld. 908
  - He, N₂, Ar, CO₂: supplied gas distribution network
- flammable gases:
  (gas mixing area, left hand side, hood #2)
  - Methane(CH₄), Ethane(C₂H₆): supplied by bottles in bld. 908
  - Isobutane(iC₄H₁₀): not used

This page was last updated on July 11, 2002 by Eric Weise