GAS M&O meeting 30 April 2020

Present: Beatrice, Roberto, Andrea, Patrick, Kacper, LPh, Fred, Michal, Mara, Gianluca, Sabino, Fabio, Federico, Leonardo

Indico: https://indico.cern.ch/event/912569/

CHECK Gas Systems

ALICE #2423

TOF

• GC analysis: SF6 at 6.72% —> change MFC SF6 to 7% (it was 8%)
• Probably a leak is present: to check when we are back. We can use the new R134a sniffer —> LPh+Fabio/Federico

Other

• Change He GC bottle

ATLAS #2427

MDT

• New pressure sensors with problem: need to change or reset when we are back. To prepare a list of sensors that stop to work or drift in order to have a clear overview —> Kacper
• Presentation by Gianluca and Kacper on overshoot pressure problem:
  • ~ 30 mbar of overshoot and 15 hours to stabilise
  • overshoot is mitigated with higher Kc: doubling the Kc reduce of half the overshot
  • overshoot vs duration power-cut in the past —> Kacper
  • Gianluca checked and the PID are the same of last year
  • Roberto proposes also to lower the Ti to ~1
  • Roberto suggests that maybe the PID box changed —> Michal to investigate
  • Beatrice asked if there could be any correlation in the change of pneumatic pipes and FESTO Cabinet. To check speed of opening of regulation valve —> Michal
  • Tests to do next week: discussion offline to discuss the procedure —> Kacper, Gianluca, Beatrice, Roberto

TGC

• To send an email to Leatitia for the safety form for preparing the intervention for when we are back —> Kacper/Gianluca

CMS #2426

RPC

• Andrea increased flow in racks 84 and 86, probably problem in flowcell reading in UX. To verify when we are back —> Michal/Mara
• Rack 80 ch 7 problem in reading: to check cables in flowcell when there is an access —> Andrea

From previous meeting:

• with the power-cut some racks went underpressure -2 mbar, this is probably due to leaks in the detectors —> Andrea to prepare list of racks with this problem

LHCb #2430

RICH2

• change pump membrane (pre-alarm of membrane pressure received, very good!)
• New compressor module: Patrick to check with LHCb if it is possible to install in flammable room.

MWPC

• change pump membrane

RICH1

• to restart the system this week or beginning of next in order to try to understand if we take Air —> Patrick
• Patrick proposed two tests:
  • Check Air intake with system running continuously
  • Check Air intake with stop and start of the system

General

• To remember that there could be the possibility of having a RPC-like mixer to install in LHCb (CODEX-b project)

GENERAL

• Presentation of 3D drawings by Leonardo:
  • 3 modules ready: mixer, exhaust and pump
  • now Leonardo is doing the purifier
  • to check mixer module and to send comment to Leonardo before next meeting —> everybody
  • missing list of material for mixer and exhaust —> Leonardo to understand if to do now or when we are back with help of technicians
  • LPh will send to Leonardo list of material for Exhaust module
• Presentation of PROFIBUS by Patrick:
  • Two possible types of check:
    • with profibus trace: we check the voltages. They have to be ~ 5V
    • with multimeter: we check the resistances. They have to be < 20 Ohm.
    • the second test looks more easy for looking at possible problems
    • for both tests the gas system has to be OFF
    • good example of ALICE TRD in slides #6 and #7
    • for doing these type of test we need 2 people and 1 day per system
  • The profibus signal of ALICE TRD was very bad with old profibus module
  • With new profibus module the signal improved a lot but still some reflections visible
  • After the change of 9 connectors the signal is now good
  • A profibus connector costs ~30-40 chf (the one that are old and that could have problem)
  • We have 29 connectors for each system
  • To do a proposal for WinCC-OA errors from profibus —> Michal
  • For Profibus signal we can have maximum 32 stations without repeater: enough for LHC but not for CLOUD —> to investigate
  • Profibus check has to be done before and after the change of PLC but it is not enough
  • Need to test all resistance in profibus connectors. Not done for all system where we changed the PLC —> to plan to do
  • Test on Profibus status in OT in order to have a procedure of all tests needed
• PGS list of sensors not working: missing ALICE
• Two lists of warnings: one for the piquet (very important for operation and to anticipate interventi to avoid a stop of the system) and one for standard operation: Michal said it is possible —> to define what we want
  •  

From previous meeting:

• Level of PGS sometimes is > 100% —> Michal to check

ACTIONS:

• To check mixer module and to send comment to Leonardo before next meeting —> everybody
• Kacper to prepare a table of ATLAS MDT pressure sensors with problem and keep it updated
• To prepare a list of sensors not working or missing in PGS —> LPh
• To send an email to Leatitia for the safety form for preparing the intervention for when we are back —> Kacper/Gianluca

From previous meeting:

• To prepare a list of sensors not working or missing in PGS —> LPh
• With the power-cut some racks went underpressure -2 mbar, this is probably due to leaks in the detectors —> Andrea to prepare list of racks with this problem
• Excel file for alarms prepared weekly by Mara —> Experiment technical responsible to fill