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Gas systems weekly project meeting
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32/1-A24 (CERN)
gas systems project meeting
Gas systems
Gas systems 2026-10-07 08:48(GMT+2:00)
Key Outcomes
The meeting addressed two main operational issues: a nitrogen incident that caused a near-miss stop of all ATLAS gas systems, and a faulty gas valve requiring seat replacement. The team also discussed alarm gaps, responsibility boundaries with external teams, and introduced a new trainee. Several action items were assigned around gas bottle inventory, system alarms, and scheduling.
Decisions Made
· ATLAS Nitrogen incident traced to pressure-controlled valves switched during dewar refill; manual override was required to go back on dewar, but not done by BE/primary gas supply team. The team agreed this must not recur and that escalation to Paolo (muon system responsible, Atlas) is needed.
· CMS RPC Valve seat replaced (not full valve) after the original seat was found stuck/degraded; seat (PTFE) and valve body (aluminum) composition/structure change/aging to be investigated further.
· Alarm gap identified: An auxiliary module alarm on nitrogen pressure was not received from new BE PGS monitoring; team will request these alarms be routed to piquet.
· Gas bottle inventory to be audited; unused/old bottles to be returned to avoid ongoing rental costs.
Completed
· 904: Bypass installed and nitrogen connection for RPC confirmed operational.
· CMS-RPC: Valve seat replacement completed; valve sent to workshop for inspection.
· ATLAS-TGC: pump swapped.
Blockers
· ATLAS Nitrogen incident detector representative did not catch the criticality of the incident during OPM meeting. Roberto to escalate to Paolo and technical coordinator.
· Gas bottle return process blocked by registration system mismatch; Patrick asked to assist.
· Electrical patch for one unit still pending completion.
Pending Confirmation
· BE-PGS upgrade Dates for primary gas supply maintenance work to be shown again at next Thursday's meeting.
· uCL: Strategy on how many spare units to produce (R&D discussion pending).
· PGS: Whether auxiliary module alarms can be added to our winccoa for all experiments following the BE-PGS modification.
· CMS-RPC valve: Metal composition analysis of the removed valve seat (possible contact with Anita's group at CERN).
· Gas bottle list to be compiled and shared next week for final return/keep decisions.
Open Questions
· CMS-RPC stop: Root cause remains unclear (purifier or other?).
· CMS-RPC Econex: Whether the valve seat size variation was caused by some chemicals attach (the long-term degradation) since it worked for years before seizing.
Action Items
· Max/Davide: Organize meeting with Paolo (Atlas muon coordinator) to escalate Nitrogen incident.
· Roberto: Send updated schedule reflecting holiday period (Jan 3–5 holidays, Jan 6–7 working days, Jan 7 = first Thursday).
· Patrick / Team: Assist with gas bottle registration and return. Prepare few slides with procedure
· Team: Compile full gas bottle inventory list for next week; identify bottles to return vs. keep.
Gas systems 2026-10-01
Action Items
· Gianluca: Verified buffer pressure alarm delay unit (5 seconds vs. 5 minutes) in recipe.-> there is an issue in the recipe -> checked again, it's in seconds (default 5 s)
· Patrick/Stefania/Gianluca: Clarify LHCb UT pipe/valve condition item; check functional analysis for manual stop behavior.
· NA62 Straw: Fabio available for up to two days; Roberto to confirm based on bottle availability.
Gas systems 2026-09-24
Action Items
· Gianluca: Investigate PLC logic for minimum valve opening threshold below 10%. CMS-RPC humidifier -> no values clipped in the PLC found
· Stefania (microcirculation): Order mechanical and electrical material; report estimated arrival at next meeting.
· Davide/Max/Gianluca: Check historical pump test record to identify which pump had the prior current absorption problem ATL-MDT. We tested VFD of pump 1 with pump 2 and it seemed ok: see https://eloggas.web.cern.ch/GASSYSOperationMaintenance/6610
Gas systems 2026 09 17
Action Items
· Davide/Max: Continue CO2 pressure-drop tests on Column B (Atlas-RPC) — check if drop rate decreases over repeated tests (saturation indicator). -> stable rate
· Davide: Perform full pump maintenance on all three RPC pumps (gasket material upgrade, needle valve replacement). -> done maintenance p2, non return completely broken. replaced. pump 2 still not ok after. Plan to replace all non-return -> something solved, but pump still not happy
Gas systems 2026-09-03
Action Items
Patrick/Gianluca: Investigate LHCb-UT, confirm correct logic and pipe (or valve or pneumatic pipes?) condition.- Andrea : finalize TID 904 and send link.
- Florian's mixer: Order required materials — planned for next week – who is ordering? Patrick for electrical
piquet:
LHCb pump filters to be changed or something (for LS3)-> TICKET
O2+H2O analyser to be checked -> TICKET
ATLAS-RPC rack 66 and 69 pressure alarm during purif 2 change over -> TICKET
NA62
glitch of CEDAR 6105, is it the keller? -> TICKET to check
ATLAS-TGC putifier Col B leak. loosing 1 bar in 1 day -> TICKET Davide check with Argon or CO2
CMS-DT pressure sensor PT1303 went to 0 for 20 minutes -> TICKET to follow Andrea
ATLAS-RPC purif -> affecting chamber pressure -> R66 check
12/2 ATL-RPC purif 1 some software issue and sms not indicating the right reason for the alarm -> TICKET
IR status, spares, .... --> TICKET
test binary gas analyser... -> TICKET
outcome of binary gas analyser test --> TICKET & buy a 2nd one --> Maria Cristina
DP pressure for pump filter in ALICE and LHCb -> TICKET -> @LPh + @Patrick [GASSYSTEMS-903] DP pressure for pump filter increasing - CERN Central Jira -> Stefania
chiller fluids to uniform between CMS, LHCb and ATLAS -> TICKET Maria Cristina
check if NV in purif is really useful --> TICKET
Calibration bottles O2-H2O status
ALICE
70 report from Anité [GASSYSTEMS-70] TPC gas quality - filters to Benoit - CERN Central Jira (I don't see the report, can you please add it?)
several alarms blocked: [GASSYSTEMS-628] ALICE alarms blocked - CERN Central Jira
TOF gas mixture analysis -> [GASSYSTEMS-639] TOF gas mixture analysis - CERN Central Jira & ELOG
TRD membrane is connected ? -> [GASSYSTEMS-717] TRD membrane status - CERN Central Jira
P&ID drawing check who is doing -> [GASSYSTEMS-736] ALICE P&ID drawing check - CERN Central Jira
MID swap of pumps during MD because sometime the system stop -> TICKET
ATLAS
MDT frequency converter (need to be replaced TICKET) ELOG - ATLAS MDT Test convertisseur 4101 avec la pompe 4201
RPC distribution rack regulation valve (TICKET)
RPC secondary mixer (TICKET), info to be given to ATLAS
RPC purif 3 circuit breakers & meeting -> [GASSYSTEMS-718] RPC purif 3 electrical issue - CERN Central Jira --> meeting when?
ATLAS-TGC flow difference --> [GASSYSTEMS-612] ATLAS-TGC flow difference - CERN Central Jira
CMS
RPC purif test at workshop, PLC needed -> TICKET
R134a insulation - isol'tut to check and see what to do -> ticket IO [GASSYSTEMS-578] R134a insulation - isol'tut to check and see what to do - CERN Central Jira
How much gas flow we need for the RPC purifier? --> [GASSYSTEMS-579] CMS-RPC How much gas flow we need for the RPC purifiers? - CERN Central Jira @MariaCristina notes to be added
RPC bypass pump too much closed --> [GASSYSTEMS-604] RPC bypass pump too much closed - CERN Central Jira
RPC with CO2 like ATLAS and effect on R134a recuperation -> [GASSYSTEMS-606] RPC with CO2 like ATLAS and effect on R134a recuperation - CERN Central Jira
R134a Upgrade (hardware and software) to be tested -> [GASSYSTEMS-594] R134a Upgrade (hardware and software) to be tested - CERN Central Jira
DT vaisala reading difference between SG and US -> [GASSYSTEMS-677] CMS DT vaisala reading difference between SG and US - CERN Central Jira
CMS-FGR -> TICKET should we add a module. Do we need to buy something? follow-up
CMS-FGR -> TICKET Maria Cristina già fatto per bypass
CMS-FGR -> TICKET flowmeter for Huber
CMS-RPC IR not stable -> elog Maria Cristina -> TICKET
CMS-ID flushing. refurbishing of old racks material and manpower need to be estimated -> TICKET @Gianluca ticket number for project
R134a huber temperature can be controlled by PLC -> TICKET
LHCb
TS1-> RICH1 leak search (postponed), SciFi some work from others expected
RICH1 what we learn from 1st fill -> [GASSYSTEMS-608] RICH1 what we learn from 1st fill - CERN Central Jira
summary of the C4F10 bottles --> TICKET or ELOG -> [GASSYSTEMS-660] summary of the C4F10 bottles - CERN Central Jira
alarms blocked: [GASSYSTEMS-631] LHCb alarms blocked - CERN Central Jira
RICH2 filter blocking -> [GASSYSTEMS-731] RICH2 pump filter differential pressure sensor not working - CERN Central Jira
P&ID drawing check who is doing -> [GASSYSTEMS-739] LHCb P&ID drawing check - CERN Central Jira
RICH1 cleaning , when? not before mid-september? -> TICKET
RICH1 remove membrane rack before end of HL-LHC operation and/or change piping-> TICKET
RICH2 injection through recuperated CF4 -> TICKET
fire detection alarms reported by Pieter, more info? but not on us. Cleaning of SG room -> TICKET
CODEX-b interlock for flammable gas detection -> Patrick
RICH1 leak repair -> December 9th tbc -> TICKET
NA62
CEDAR maintenance needed -> [GASSYSTEMS-609] CEDAR maintenance needed - CERN Central Jira
change of pressure sensor used for leak warning? -> [GASSYSTEMS-741] NA62-CEDAR move to keller pressure sensor? - CERN Central Jira
GIF++ TGC gas system and return flow: [GASSYSTEMS-624] GIF++ TGC gas system return flow - CERN Central Jira
[GASSYSTEMS-674] MFCs to be checked - CERN Central Jira :
- Fondoscala del MFC di R134A e sensore umidità del gas RPC [GASSYSTEMS-645] Fondoscala del MFC di R134A e sensore umidità del gas RPC - CERN Central Jira
- Neutrino platform gas analysis: [GASSYSTEMS-622] RE: Analisi di outgassing di diversi materiali - CERN Central Jira
- ALICE T10 MFCs: [GASSYSTEMS-669] ALICE T10 TR: calibration MFC pour C4F10 - CERN Central Jira
- ND280 MFCs to check [GASSYSTEMS-679] ND280 MFCs to check - CERN Central Jira
non-LHC safety valve --> check lista di Fabio
[GASSYSTEMS-172] non-LHC safety valves to be verified - CERN Central Jira
ELOG - safety valves to be verified for non-LHC systems
Additional requests/projects/discussions
887 CEDAR new "mixers" --> [GASSYSTEMS-509] CEDAR for beam lines - CERN Central Jira
AMBER
EDMS leak test?
test certificate x-ray?
ATEX certificate?
who is technical coordinator
resource manager Oleg D?
no money? should we stop? and resume in 2026?
Commissioning when? -> TICKET
when they would like to start? Moritz? -> ask
LEAK DETECTORS LIST -> TICKET
MAINTENANCE INTERVENTIONS WORK ORDER FOR STATISTICS -> TICKET
PROJECT 2025
summary TICKET
examples of topics for the common discussions:
-cms id flushing -> Andrea
-cms r134a operation and spare -> Andrea
-cms cf4 operation and spare -> Andrea
-atl tgc nc5h12 -> Kacper
-Analysis boxes -> LPh
-C4F10 new recuperation installation -> Patrick
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