Operating the VELO Vacuum System under beam conditions

Make sure the PVSS-project "VEDCS_VacMot" is running under "velo_user" on "vedcs02w". If not, start it. If "gedi" is not running, start it. Start via "Vision" the panel G:\velo\pvss\VELO_VacuumMotion\panels\VeloVacuum_UI_Main.pnl

  • Click on "Show Details/Hide Details" (left top) to get information of more/fewer vacuum meters.
  • The most important ones are the 4 red encircled ones: PE411 and PE412 give the pressure in the beam volume in mbar. The pressure in the detector volume of the VELO is given by PE421 and PE422.
  • The status of the sector valves VVFSF.33.1L8.X and VVGST.221.1R8.X will in the near future also be displayed at the left/right side of the beam pipe.
  • The overall state of the vacuum system is represented by the field "Current state" on the bottom of the panel. The state "Ready for Beam" is what you need, from the vacuum point of view, to permit injection of beams into LHC.


Trend plots of the pressures in the beam and detector volumes can be obtained in the following way:

  • Left-click button 'Open Graph Select' in the top left corner
  • Select "VEDCS_VacMot" << "Vac_VesselSide" << "Pennings_vessel"
  • right-click it this last field
  • left-click field "view"
  • You get a trend plot over the last 2 hours. You can change this period by means of the "Time Range" tab in the top left corner of the plot.

The sector valves VVFSF.33.1L8.X and VVGST.221.1R8.X, that seperate LHCb from LHC, can only be opened by AT-VAC if at least one of the ion pumps IP431/IP441 is on.

The state "Ready for Beam" is a combination of a several conditions, some of which can be overruled via a so-called "ignore"-action. This can only be done at the PLC-screen and is password protected. So if the vacuum system is NOT in the state "Ready for Beam" you cannot do much about it. The following information is there to help you to find the cause such that you can better judge what to do and/or who to call. Below it is assumed that no "ignore"-actions have been taken. "Ready for Beam" is defined as an AND of the following 11 conditions:

  • PS100=OK && PS200=OK (where OK means among other things PI101<1.0E-1 && PI201<1.0E-1 mbar)
  • PI102<1.0E-1 && PI202<1.0E-1 mbar
  • PS300=OK (where OK means GV302=closed && PI301<1.0E-3 && PE301<1.0E-6 mbar)
  • PS110=OK && PS210=OK (where OK means among other things PI111<1.0E-3 && PI211<1.0E-3 && PE111<1.0E-4 && PE211<1.0E-4 mbar)
  • PV301, PV302, PV303, PV304, PV305, PV306 and SV421 are closed
  • PI411<1.0E-3 && PI412<1.0E-3 mbar
  • PE411<1.0E-6 && PE412<1.0E-6 mbar
  • PI421<1.0E-3 && PI422<1.0E-3 mbar
  • PE421<1.0E-4 && PE412<1.0E-4 mbar
  • operating high voltage of ion getter pumps IP431 and IP441 > 2.5 kV
  • current drawn by ion getter pumps IP431 and IP441 < 1.0E-3 A

The actual readings of gauges, valves and pumps can also (and partly better) be seen at the page named "Vacuum scheme" on the PLC-screen in rack C3B05 on platform C3. To display it, touch the screen once to get rid of the screensaver and then press the encircled button as shown in the figure below. Much more detailed information on the vacuum system can be found in EDMS-901535. See https://edms.cern.ch/document/901535/1


-- EddyJans - 31 Jul 2008

Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg pvvs.vacuumscreen.bmp.jpg r1 manage 107.1 K 2008-07-31 - 15:05 EddyJans  
JPEGjpg pvvs.vacuumscreen2.bmp.jpg r1 manage 110.8 K 2008-07-31 - 17:35 EddyJans  
JPEGjpg screenshot.4b.jpg r2 r1 manage 65.2 K 2008-08-05 - 15:10 EddyJans  
JPEGjpg screenshot.mainpanel.2.jpg r1 manage 65.2 K 2008-08-05 - 15:12 EddyJans  
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