Phase 2 R&D – Brief Introduction – GE2/1 Phase 2 R&D – Brief Introduction – Marcus Hohlmann Florida Institute of Technology Paolo Vitulo Università di Pavia & INFN Pavia GEM Workshop XV, CERN, July 21, 2016

Phase 2 R&D, GEM workshop XV, CERN Where are we now? GE2/1 GE2/1 Triple-GEM baseline: We pretty much have a consensus on basic geometry 20-degree chamber made from 4 trapezoidal modules Full-size mechanical mock-up of sector constructed Mechanical details of modules being worked out We are converging on the conceptual layout of the readout board (partitioning; number of OH’s) µRWELL option: First large prototype (GE1/1-size) currently under construction Michele’s talk Luigi’s talk 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN Where are we now? ME0 Triple-GEM baseline: Back-to-back design option underwent first beam test with small prototype; promising first results Have recognized the need to revisit discharges in GEM Not an issue in GE1/1, but in ME0 rates much higher Investigating how to measure discharge rate induced by hips Neutron irradiation New α-tests on lab bench (opportunity for an offsite group) FTM option: 3 small prototypes developed and tested so far Timing measurement in 2015 beam test (~ 2 ns res.) Latest prototype being revamped Paolo’s talk Ilaria’s talk 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN GE2/1 R&D Schedule I GE2/1 Triple-GEM Baseline 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN GE2/1 R&D Schedule II GE2/1 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN ME0 R&D Schedule I 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN ME0 R&D Schedule II 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN Thank you! 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Phase 2 R&D, GEM workshop XV, CERN BACKUP 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN

Discharge test with Triple-GEMs Accumulation of 450 discharges over a few cm2. However, conditions quite different from those in CMS. Observations: Discharges are non-destructive No impact on gain Thin deposition of copper oxide in the irradiated region (all GEM foils) Superficial copper etching near the rim of the holes These do not affect the detector operation In CMS, for ME0 we expect ~1.5 × 10-5 discharges s-1 cm-2, or ~ 5 × 10-5 discharges per second over a few cm2, or one discharge every ~2 × 104 seconds over a few cm2. => The test corresponds roughly to 9 × 106 s of running in CMS, i.e. 15% of the total expected up-time of 6 × 107 s of the HL-LHC over 10 years. Caveat: There are large uncertainties in these estimates! Conclusion: Promising, but need to revisit estimates and do more tests to reach 10 HL-LHC equiv. years. If this indeed poses a problem, investigate mitigation. Charge 6

Performance - big picture ME0 GE2/1 RE3-4/1 Performance Parameter Baseline requirement Additional requirement (option) 3-GEM FTM µRWELL Std. RPC iRPC MRPC Rate capability 2 kHz n/a ok 90 kHz (SF3) Trigger time resolution < 8ns < 2ns no < 100 ps maybe Bending angle Δφ with CSCs φ resolution < 0.3mrad Reconstruction spatial resolution ≈ 400 µm 0.8 – 1.7 mm Operation eco-friendly gas 7/21/2016 Phase 2 R&D, GEM workshop XV, CERN