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VELO Vacuum Troubleshooting


Introduction

The first responsible to contact in case of problems with the VELO vacuum system is the piquet of the CERN vacuum group. This can be done via the CCC. During working hours you can also get in contact with Giuseppe Bregliozzi or Didier Calegari.

UPS of the vacuum system

The vacuum system has its own UPS. It is an APC RT 5000 RM XL, of which the most relevant settings are given in tar-file

UPS of the baratrons

The baratrons have their own UPS. This is only in place when they are connected to the proper plug near the VELO, i.e. the one under the horizontal metal plate near the floor on the C-side. The most relevant settings of this UPS are given in this tar-file .

Vacuum interlock at injection

Problem: impossible to inject beam (at LHC) because of vacuum interlock in the VELO.

One of the possible reasons is that the section valves (VV033L and VV198R in picture) are closed and the LHC is unable to open them because the SMOG system is on (even if not gas is being injected).
If the SMOG is ON the ion pumps (IP431 and IP441 in picure) are off to avoid being contaminated by the SMOG gas.
When these valves are off the LHC cannot open the section valves because of risk of contamination to the rest of the LHC vacuum.
The solution is: ask the vacuum piquet to switch off the SMOG, switch on the ion pumps and open the valves.

Note: those valves should be open, but in case of access they are closed.

vaccuum_detailed.png

-- EddyJans - 2015-04-17

Topic attachments
I Attachment Action Size Date Who Comment
Compressed Zip archivetar screenshots.upsbarat.tar manage 1130.0 K 2011-07-28 - 19:17 EddyJans barset
Compressed Zip archivetar screenshots.upsvac.140430.tar manage 1440.0 K 2015-04-17 - 13:46 EddyJans vacuum UPS screenshots
PNGpng vaccuum_detailed.png manage 67.4 K 2018-07-01 - 16:04 FrancescoDettori Vacuum detailed view
Topic revision: r3 - 2018-07-01 - FrancescoDettori
 

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