22022021 J A Merlin On behalf of the

22/02/2021 J. A. Merlin On behalf of the CMS Muon Group 1

Detector HV Instability à Developed a discharge monitoring station to identify events that cause HV trips à Completed, system is operational à GEM Stress test including advance cleaning in Ar/CO 2 à Detector equipped with electronics and under QC 7 validation à Improved QC 6 protocol including GEM stress test in pure CO 2 Electronics Integration Data Base (? ) à Need input from Jared/Marcello GBT Unlocking à Investigate electrical and thermal hypothesis à Plan is established à Setup being prepared QC 7 Test Rate à Need to increase the test rate and/or increase the number of à Implement an automatic restart test running in parallel procedure for QC 8 chambers à Third QC 7 Station is after a trip under preparation à Additional CTP and à New hypothesis: discharges fibers will be available caused by mechanical shocks ? (need to investigate further) à Investigate alternative HV filter and impact on VFAT damage probability 22/02/2021 DAQ Performance Calibration Low Efficiency à Implement parallel calibration SW à Prototype script ready to be tested à Develop a GEM Event Format specific to the calibration and zero suppressions modes à Prototype script ready to be tested à Create an unpacker version compatible with the specific calibration GEM Event à Work in progress OH bugs SBIT clustering and timing à Investigate sources of noise and optimize VFAT configuration to achieve low threshold à Need to evaluate what was already done à Preliminary plan established à Setup being prepared à Measure the detector gain on the QC 8 stand compare to the expected values à Procedure and equipment are known à Operate a SC with HV divider à Operate a SC with the three VFAT hybrid versions à FW issue à Need to investigate Noise Rate Specification à Develop analysis tools to select appropriate threshold based on “signalto-noise” desired ratio à Work in progress J. A. Merlin On behalf of the CMS Muon Group Data Loss à Mitigate issues in DAQ link, event building etc … à Problem solved by a FW fix with auto re-sync of the system 2

Detector HV Instability à Developed a discharge monitoring station to identify events that cause HV trips à Completed, system is operational à GEM Stress test including advance cleaning in Ar/CO 2 à Detector equipped with electronics and under QC 7 validation à Improved QC 6 protocol including GEM stress test in pure CO 2 à Implement an automatic restart procedure for QC 8 chambers after a trip à New hypothesis: discharges caused by mechanical shocks ? (need to investigate further) HVElectronics Instability: - DAQ - à Work in progress known à Operate a SC with HV divider Automatic HV restart after a trip: new feature. Nalready implemented and deployed to the e w OH bugs QC 7 Test à Operate a SC with the three VFAT hybrid QC 8 DCSRate (Ilaria). versions SBIT clustering and timing à Need to increase the test rate - New hypothesis: the high rate of discharges observed on QC 8 could be due to and/or increase the number of à FW issue test running in parallel à to investigate mechanical shocks (observed on Need QC 6), will be discussed during next PFA meeting before à Third QC 7 Station is starting further investigations (Margaux and Felipe, supervised by Jeremie) under preparation à Additional CTP and Data Loss Noise Rate to lower the VFAT damage probability. fibers will be alternative available - Investigate HV filter scheme à Mitigate issues in DAQ link, event building Specification Discussions are on-going with Pigi and his team (need to define etc … persons in charge) à Problem solved by a FW fix with auto re-sync of the system à Investigate alternative HV filter and impact on VFAT damage probability 22/02/2021 Performance Discharge monitoring station: ready and operational. Used continuously the past 4 Integration weeks to monitor the discharge rate and propagation (Océane, supervised by Jeremie). Results will be discussed at the next PFA meeting Calibration Low Efficiency Data Base (? ) à Investigate of noise and optimize à Implement parallel calibration - GEM stress test in Ar/CO 2: detectors need to be SW first validated onsources QC 7 before applying VFAT configuration to achieve low à Prototype script ready to voltage to make sure the procedure does not harm the electronics. The work is in à Need input from threshold be tested progress but we had to à fix. Develop several problems, we expect to have it ready by the end Jared/Marcello à Need to evaluate what wasof already a GEM Event Format done specific to calibration and. Francesco) zero next week (Océane, supervised bythe Jeremie and à Preliminary plan established suppressions modes GBT Unlocking à Setup being prepared à Prototype script ready to GEM stress and several be tested has been established à- Investigate electricaltest and in CO 2 : QC 6 procedure à Measure thetested detectorwith gain on the QC 8 à Create an unpacker version thermal hypothesis chambers. The QC DAQ SW is also updated (Margaux andstand Felipe, supervised and compare to theby expected values compatible with the specific à Plan is established Procedure and equipment are Francesco and Jeremie), now part of the standard productionàprocedure. calibration GEM Event à Setup being prepared J. A. Merlin On behalf of the CMS Muon Group 3

• Discharge monitoring station: § Using the “vertical” SC setup § Discharge monitoring stations made of antennas inserted in the HV cable and HV probes connected to G 3 b of both detectors • Settings: § § § Trigger level (antennas) = 30 m. V Gaz flow = 6 l. h-1 Imon GE 1/1 -X-S-CERN-0008 = 705. 473 µA Imon GE 1/1 -X-S-INDIA-0008 = 702. 262 µA I 0 = 5 µA (probes “inject” 3 µA) G = 2 x 104 Slide prepared by Océane Perrin 22/02/2021 J. A. Merlin On behalf of the CMS Muon Group 4

Primary + GEM 2 +GEM 3 + INDUCTION = full Typical antenna+probe signals Example of “fake” signals 22/02/2021 J. A. Merlin On behalf of the CMS Muon Group 5

2 Chambers Date Fake # Discharges (total) Discharges (primary + GEM 2) Discharges (Full) Trips 04/05/2019 25 28 24 ± 3 1 1 2 05/07/2019 137 87 81 ± 23 3 1 2 06/07/2019 22 23 20 ± 5 1 1 1 07/07/2019 16 28 18 ± 5 5 5 0 08/07/2019 26 19 15 ± 5 1 1 2 Total 226 185 158 ± 24. 8 11 9 7 Chamber Total running time # Trip GE 1/1 -X-S-CERN-0008 80: 02: 00 2 GE 1/1 -X-S-INDIA-0008 62: 09: 00 5 Rdischarge (all det. ) ~ 1. 1 ± 0. 17 [/hr] Rfull Propa (all det. ) ~ 0. 06 [/hr] 22/02/2021 Slide prepared by Océane Perrin J. A. Merlin On behalf of the CMS Muon Group 6

250 50 45 150 discharge 40 fake 35 Events 30 discharge fake Events Number 200 Slide prepared by Océane Perrin 06/07/2019 05/07/2019 25 100 20 15 50 10 0 0: 01 A 7/P 74: 48: 01 A 7/P 79: 36: 01 A 7/P 7 14: 24: 01 A 7/P 7 19: 12: 01 A 7/P 7 0: 01 A 7/P 7 Time 5 0 0: 01 A 7/P 7 4: 48: 01 A 7/P 7 9: 36: 01 A 7/P 714: 24: 01 A 7/P 719: 12: 01 A 7/P 70: 01 A 7/P 7 Time 07/07/2019 50 08/07/2019 45 50 discharge 45 35 fake 40 discharge 30 Events 35 fake 30 Number 40 25 25 20 20 15 15 10 10 sunday 5 5 0 0: 01 A 7/P 7 4: 48: 01 A 7/P 7 9: 36: 01 A 7/P 7 14: 24: 01 A 7/P 7 19: 12: 01 A 7/P 7 0: 01 A 7/P 7 0 0: 01 A 7/P 7 2: 24: 01 A 7/P 7 4: 48: 01 A 7/P 7 7: 12: 01 A 7/P 7 9: 36: 01 A 7/P 7 12: 00: 01 A 7/P 7 14: 24: 01 A 7/P 7 Time 22/02/2021 Events J. A. Merlin On behalf of the CMS Muon Group Time 7

• New cleaning procedure: GEM stress test in Ar/CO 2 § With the ”Vertical SC”: § We perform QC 7 to take a reference picture of the electronics § We perform the advanced cleaning test (stress test) in Ar/CO 2 § We repeat QC 7 to evaluate the effects of the stress test on the electronics § For detectors already on QC 8 (column 1 and 2): § Two options are available: Options 1: - We keep running the detectors at efficient gain and accept possible loss of VFAT channels - We cannot anticipate how much damage but it will help us to collect data and better understand the situation - These chamber will come back in September 22/02/2021 Options 2: - We interrupt the data taking for ~ 2 days to perform a stress test in Ar/CO 2 followed by a QC 7 to confirm the electronics is fine Or - We switch back to pure CO 2 on QC 8 to perform an advanced QC 6 in situ (~3 days at least) J. A. Merlin On behalf of the CMS Muon Group 8

• New QC 6 procedure: GEM stress test in pure CO 2 1. GEM cleaning with Megger (550 V) 2. Continuity test at LV 3. Stress test: § Each foil ramps up to 1000 V with tight settings (2 u. A, 1 s) § Foils will trip when reaching their max ΔV § Test performed 3 times for each foil 4. Stability test for 4 hours à We already observed a significant improvement of the detector stability after the stress test à More news very soon after we collect more data 22/02/2021 J. A. Merlin On behalf of the CMS Muon Group 9

HV trip after a chair moving or a poke on the chamber (small mechanical shock) Settings Antenna signal VO Current Limit Trip Time Drift 999 V 2 u. A 1 s G 1 T 550 V 2 u. A 1 s G 1 B 394 V 2 u. A 1 s G 2 T 550 V 2 u. A 1 s G 2 B 787. 5 V 2 u. A 1 s G 3 T 550 V 2 u. A 1 s G 3 B 562. 5 V 2 u. A 1 s Comments : - Overcurrent on each pin (G 1, G 2 and G 3) - This trip occurred after 2 hours of stabilization - 50�� terminations were in place on the chamber RO THIS LED TO A TRIP Slide prepared by Margaux Forge 22/02/2021 J. A. Merlin On behalf of the CMS Muon Group 10

§ One SC with the HV divider is ready to go to QC 8 § When/where? § Effective gain on QC 8 was 2 x lower than expected for one detector (in two different posision) § How significant is this? § Do we want to extend this study? § Alternative HV filter to reduce the damage probability § Need to define the priority § Need to define the manpower § Need to define the setup (clash with third QC 8 column ? ) 22/02/2021 J. A. Merlin On behalf of the CMS Muon Group 11

Possible ground loop after mounting SC: Opening in the Faraday cage Cooling Plate Insulated screws Chimney Exterior Detector Frame SC Back Plate Chimney Possible ground Detector Frame loop and mechanical stress Interior Detector Electronics Insulated screws