Marcus Hohlmann (Florida Institute of Technology) with C. Armaingaud, S. Colafranceschi, R. De Oliveira, and A. Sharma (CERN) on behalf of the CMS GEM Collaboration Construction & Commissioning of Full-size GEM prototypes for the CMS High-  Muon System Nov 1, IEEE Nuclear Science Symposium, Anaheim, CA N38-6

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 2 MOTIVATION & INTRODUCTION

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 3 Premise for CMS GEM upgrade CMS was designed with a “hermetic and redundant muon system” – Joe Incandela, CERN “Higgs Discovery” Event, 7/4/12 But: CMS currently has the least redundancy in the most challenging muon region, i.e. at |η| > 1.6: RPCs descoped; only Cathode Strip Chambers currently present Long-term functioning of the muon system into LHC Phase II (beyond Long LHC Shutdown 3) is of vital interest for CMS. Use Phase I to evaluate muon technology for Phase II. The high-η muon region in particular will need robust and redundant tracking and triggering at the anticipated higher muon rates  Additional muon detectors with high spatial and temporal resolution in the high-η endcap region could bring benefits in triggering, reconstruction, and ID for muons: → GEMs

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 4 CMS GEM Endcap Chambers The currently un-instrumented high-  RPC region of the muon endcaps presents an opportunity for instrumentation with a detector technology that could sustain the radiation environment long-term and be suitable for operation at the LHC and its future upgrades into Phase II: GEM Detectors GE3/1 GE4/1 GE1/1 in YE1 nose GE2/1 on back of YE1 CMS Detector

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 5 Method of Integration into CMS Four superchambers in their final position Installation sequence: A. Conde Garcia Mounting on yoke disk Superchamber (Two Triple-GEMs)

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 6 Expected Benefits for Reconstruction & Trigger M. Maggi (Bari) – GEM Workshop 3 Strip Readout granularity: # GEM strips / # RPC strips (orig. TDR) Expected gains in momentum resolution at high-p T Acceptance impact:  distribution of 4 muons in H → ZZ → 4µ Paolo Giacomelli (Bologna) & Markus Klute (MIT) – GEM Workshop 3 1.6<  <2.4 for one GEM station Expected CSC inefficiency at PU=400 due to Cathode LCT - Anode LCT timing mismatching Staving off looming muon trigger inefficiencies at high-  Simulation A. Safonov (Texas A&M)

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 7 CONSTRUCTION OF FULL-SIZE GEM PROTOTYPES

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 8 Evolution - GEM foil stretching Current state-of-the-art: Self-stretching assembly without spacers (CERN) Readout PCB GEMs Drift electrode Tightening the horizontal screws tensions the GEMs & seals gas volume Detector base pcb R. De Oliveira, CMS-GEM/RD51Workshops CERN & U. Gent Allows re-opening of assembled detector for repairs if needed. only glue joint in assembly 2012

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 9 3 rd CMS GE1/1 Prototype: “Self-Stretched - Sans Spacer” GEM tensioning GEM foil in inner frame assembly GEM foil with inner & outer frame Inside of readout board with O-ring seal Chamber closed by readout board with Panasonic connectors for frontend electronics compact HV divider Vias for strips sealed w/ kapton HV noise filters  -sector with 384 radial readout strips (12.4 cm long) base pcb with drift electrode 2012 No spacers in active volume

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 10  GEM active areas: 990 mm  ( ) mm  Single-mask technology  1D radial strip read-out with 3  8  128 = 3,072 channels  HV sectors: 35  3/1/2/1 mm gap sizes  Gas mixtures:  Ar/CO 2 (70:30; 90:10)  Ar/CO 2 /CF 4 (45:15:40; 60:20:20)  Gas flow: ≈ 5 l/h The new self-stretching technique has been applied to the full-size CMS GEMs Production of 5 prototypes launched in May 2012 CMS Full-size GE1/1 Detector Prototype

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 11 Prototype Production: Status & Plans 4 chambers completed at CERN 2 in SPS test beam in summer; 3 rd being prepared for fall TB Some issue with dust particles from fiberglass frame getting into active GEM area in first two prototypes micro sand blasting & polyurethane coating of frames → change to different material (PEEK) for inner frame that holds GEMs 1 st chamber to be assembled and commissioned outside CERN this fall (at Florida Tech) Frame after machining After sand blast After PU coating

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 12 Rui De Oliveira As a lot of dust was released during the screw insertions into FR4 frames, CERN has replaced FR4 by PEEK for inner frames. PEEK is one of the best polymers in terms of: -radiation tolerance -mechanical properties -outgassing -chemical resistance Next Prototype: No Gluing & PEEK frames Use O-ring to seal outer frames to drift plane Panasonic readout connector Readout PCB GEM foils Outer frame Inner frame Drift Board On-foil protection resistors

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 13 We are now below 2 hours for the GE1/1 assembly with the self-stretching technique (after gluing outer frames to drift) Three 30cm  30cm detectors have been produced Up to now  ok Four 1.2m  0.45m detectors have been produced 2 tested OK  but gain uniformity still to be improved 2 others currently being tested Four new ones will be produced with all the improvements to reach final specifications (< 30% gain non-uniformity) Preparing a new laboratory for CMS GEM assembly and quality control at CERN (spring 2013) Rui De Oliveira Summary of GEM production & Plans

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 14 COMMISSIONING OF FULL-SIZE GEM PROTOTYPES

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 15 CMS GEM Summer Test Beam Effort at SPS See Poster N14-137

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 16 3 rd GE1/1 Prototype: Commissioning ResultsPreliminary Preliminary 2012 test results (bench tests & beam test at SPS H4) Fe 55 spectrum Rate plateau Gain uniformity

Long-term Aging Test at CERN GIF lead shield The CMS full-size prototype has been installed in the CERN Gamma Irradiation Facility over the summer The detector performance is being monitored along with environmental/gas variables  Ensure long-term operation in CMS  Understand the effects of the radiation on the materials  Understand aging origin (if any) and propose solutions Motivations GEM settings: Drift: 3kV/cm, Others: 3,5 kV/cm Induction: 5 kV/cm Gain: 8 x 10 3 – 10 4 Gas Mix: Ar/CO 2 /CF 4 (45:15:40) CMS high- η maximum integrated charge Gain of 2x MHz/cm 2 X-rays, 10 days = > 20 C/cm 2 integrated (LHCb) CMS prototype Armaingnaud/Merlin/Rohee/Furic/Buhours See Poster N14-138

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 18 Continuing R&D: Zigzag strips to reduce readout channel count while maintaining high spatial resolution CAD Design by C. Pancake, Stony Brook 2 mm Preliminary Results Beam Test 2012 Zigzag Resolution:  /  2 = 73 µm With 2mm strip pitch

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 19 PLANS FOR INSTALLATION IN CMS

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 20 GE1/1 ME1/1 GE2/1 ME2/1 YOKE GEM Installation in LHC Long Shutdown 1 P5 CAVERN UXC Proposed to CMS Upgrade Management 4 GEM chambers in LS1 CMS Integration and Installation of 2 GE1/1 superchambers = 4 GE1/1 chambers (and possibly 1 super-chamber GE2/1) Measure in situ: Rates, Background/Noise, Stability, Uniformity, Efficiency Spatial resolution – In the actual high-η environment – In actual magnetic field Split signal to CSC and participate in CMS muon trigger and reconstruction Install new pre-production TMB prototypes on chambers that overlap with GEMs Prove that the electronics design is working and demonstrate in situ that we can operate CSC TMB with GEM input in various operating regimes Reduce CSC X-Y ambiguity and ghosts Once we go into beam operations, we will demonstrate the above again, this time measuring muon trigger rates and efficiency with and without GEMs. Participate in CRAFT 2014

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 21 GEM DAQ Prototype System for LS1 P. Aspell DAQ also with link to new CSC Trigger Mother Board Gigabit Link Interface Boards

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 22 Summary & Outlook Long Shutdown 1 (LS1) 4 full-size GE1/1 detectors successfully constructed using simplified self-stretch & sans spacer technique; being validated GEM electronics and DAQ prototype underway Installation, services, and integration with CSC’s underway Zero additional cost to CMS upgrade projects GEMs to participate in CRAFT 2014 Long Shutdown 2 (LS2) A GE1/1 station can be completed and installed in LS2 Capacity in CERN Workshop to produce all (72 validated) detectors in 2 years; final electronics ready for 2015 Cost 2-3 MCHF

11/1/2012 M. Hohlmann - Construction & Commissioning of Full-size GEM Prototypes for the CMS High-eta Muon System; IEEE NSS 2012, Anaheim, CA 23 Thank you for your time! We would like to explicitly acknowledge here the strong technical support received from the RD51 Collaboration for this project!