RPC weekly meeting

Monday 24 Nov 2025, 09:15 → 10:30 Europe/Zurich

CERN

Davide Boscherini (Universita e INFN, Bologna (IT)), Giulio Aielli (INFN e Universita Roma Tor Vergata (IT)), Mohamed Zaazoua (University of Science and Technology of China (CN))

Weekly meeting about the RPC system activities

• List of interventions or pending issues:    follow this link

09:15 → 09:25 Communication to/from gas group

Speakers: Beatrice Mandelli (CERN), Enrico Pastori (INFN e Universita Roma Tor Vergata (IT)), Gianluca Rigoletti (CERN), Giulio Aielli (INFN e Universita Roma Tor Vergata (IT)), Kacper Kapusniak (CERN), Roberto Guida (CERN)

09:25 → 09:35 Detector and trigger reports (incl. BIS78)

Speakers: Alessandro Polini (Universita e INFN, Bologna (IT)), Claudio Luci (Sapienza Universita e INFN, Roma I (IT)), Enrico Pastori (INFN e Universita Roma Tor Vergata (IT)), Enrico Tusi (INFN e Universita Roma Tor Vergata (IT)), Eric Ballabene (University and INFN, Bologna (IT)), Dr Federico Lasagni Manghi (Universita e INFN, Bologna (IT)), Giulio Aielli (INFN e Universita Roma Tor Vergata (IT)), Mr Mohamed Zaazoua (University of Science and Technology of China (CN)), Sinem Simsek (Istinye University (TR))

BMS.C.10.CO.Ly0 HV channel 

• SPC Gas gap firstly masked without reducing the HV of the HV channel [e-log]
• Gas gap driving high current also contributing to high rate of s17_t4 (1.2kHz instead of ~1Hz).
  BMS5C10.PI.Ly0.ETA Vth lowered from 0.7 to 0.3 [e-log].
• Gas gap still driving high current, HV lowered to 8000V [e-log]
• Gas gap still driving high current, HV lowered to 5000V and gap unmasked [e-log]
• Cavern intervention: chamber disconnected, HV channel brought back to nominal [e-log]

 

RPC BMS.A.16.CO.Ly1 HV channel

• SPC Gas gap driving high current (60uA at 9056V).
  Already at 5000V, the SPC gas gap was driving high current (32uA).
  HV channel lowered and masked. [e-log]
• Cavern intervention: chamber disconnected, HV channel brought back to nominal [e-log]

 

RPC HV channels in S11/S12

• 6 RPC HV channels in sectors 11 and 12 went OFF [e-log]
  The HV board went into Undervoltage state (with Vmon ~100V), lowering the HV for all 6 connected channels. 
  The board was responding to DCS but not setting the HV consistently.
  The board had been switched off, and the corresponding channels had been masked. 
• Cavern intervention: HV board giving Undervoltage error has been replaced with a spare [e-log]

 

Cavern intervention on 19/11 [e-log]

• See the previous points.

 

BOS5C08 Vpad iCalib set to 11.0 from 15.7 because s13_t4 not reachable [e-log, e-log] 

• While ATLAS was running without beams in the machine, a TTC restart was performed, which did not resolve the problem.
  After that, the trigger was put on hold and a power cycle performed from DCS on the two RPC PADs BMS5C08 and BOS5C08, followed by a second TTC restart. The issue persisted. It therefore seems to be a hardware issue that cannot be fixed without access to the cavern. It might also be related to the toroid ramp-dow.

 

BML4C07.CO Vee [e-log]

• RPC was in NOT_READY due to an error of BML4C07.CO Vee.
  BML4C07.CO Vee at 1.8A instead of 2.2A -- masked.
  BML4C07.CO Vpd, that was already masked, gives OverCurrent.

09:35 → 09:45 Plan for YETS

Speakers: Ahmet Renklioglu (Istinye University (TR)), Alessandro Polini (Universita e INFN, Bologna (IT)), Claudio Luci (Sapienza Universita e INFN, Roma I (IT)), Dmitri Kharchenko (Joint Institute for Nuclear Research (RU)), Enrico Pastori (INFN e Universita Roma Tor Vergata (IT)), Giulio Aielli (INFN e Universita Roma Tor Vergata (IT)), Uladzimir Kruchonak (Joint Institute for Nuclear Research (RU))

YETS25-26_RPC_ResinInjection_Planning.xlsx