Muon news from Upgrades Week - I

1. Muon news from Upgrades Week - I • GIF++: more coordination of planning needed • Among CMS muon systems (shadowing?), in CMS, and LHC-wide • CF4 as a greenhouse gas (GWP = 7390, lifetime 50000 yrs) • GEMs: define baseline without CF4 (poorer timing) • CSC: investigate R&D for eliminating CF4 (CF3I??) • CSCs and L1 trigger latency • Tracker front-end hits an important boundary at 12.5 us • CSC simulations at 10, 20 us: should repeat at 12.5 us; then verify; can we live with these results (versus huge replacement program)? • RE3/1, RE4/1: bakelite RPC only need minor improvements • Improvement factors only ~ 2 to 4 required • No justification for ~100 ps timing given Tracker points to vertex • Need to check that RPC Splitter links (GOL) are compatible with upgraded L1 Forward Muon Track Finder

2. Muon news from Upgrades Week - II • Muon simulation • First plot showing ME0 background rates (well, fluxes) • Expected hit rates ~100 kHz/cm2 (10-3 of rate capability) • More attention needed for neutron, photon, charged background rates • In order to understand existing detectors • In order to build confidence in simulation for ME0 particularly • Comparisons of data (CSC, RPC, DT) hit rates to each other • Compare data hit rates to FLUKA and GEANT ME-0 ME-1/1

3. Muon news from Upgrades Week - III • Importance of new muon detectors for L1 trigger not well understood with functional Track Trigger • L1 momentum supplied by Tracker • Muon system used primarily for pointing to the Tracker • What needs to be understood: • Rate limits for muon-only tracks to matching? • Muon system matching accuracy needed? • How good is TT efficiency at high eta? • Is high-eta TT simulation now stable? • Difference between Associative Memory (AM) versus FPGA designs for TT?

4. Muon news from Upgrades Week - IV • Challenge from spokesperson on physics of muon upgrade • See following slide – need workshop <June but when? • Involve Upgrade Performance Studies group, muon POG, muon DPG, and simulation teams

5. Some considerations from this week: muons From CB meeting: Tiziano • We need to beef up the physics case • In the near future we will need to have a clear view of how to reconcile the apparently parallel threads on the choices/options for muon upgrade description in the TP for Phase 2 and the GE1/1 ‘project’ that will reach “TDR level” by the fall • We should probably plan for a dedicated workshop on this CMS Upgrade week , T. Camporesi

6. Future Meetings 1. Phase 2 TP: next update for reader group • Contact group meets Thursdays, next release planned April 17 2. Costing: new estimate needed for Management by April 31 • Fabrizio will discuss about that next 3. Dedicated meeting on measured & Phase 2 background rates • Week of April 22-25 after AGR? • Summarize at GMM of April 28? 4. Workshop on “Physics of the Phase 2 muon upgrade” • Hold it before June to motivate the upgrades included in TP • Possibly 2-3 days • Seems that April is too soon, look for dates after Fermilab workshop on upgrade physics, e.g. • 12th-14th , starting afternoon of the 12th

7. Backup

8. Areas of Phase 2 muon interest 1. Consolidation of existing detectors DT, CSC, RPC • To handle 6x more integrated and 5x more instantaneous luminosity than design • To last ~30 years • To reduce or eliminate greenhouse gas emissions 2. Completion of the forward region 1.6<h<2.4 • Redundancy as originally foreseen 1997 in the muon TDR • Improved high luminosity triggering (lowered thresholds) • New technologies that handle the high rates and complements the CSC, i.e. thin & simple GEM and iRPC 3. Muon tagging for h>2.4 • One GEM station within a rebuilt endcap calorimeter • Up to as high as 4.0 depending on the calorimetry

9. Consolidation – GIF++ muon planning • NB need additional infrastructure, need for CMS & CERN–wide coordination • Numerous chambers into GIF++ (ME1/1, ME1/2) starting late 2014/early 2015, ~8 months irradiation • Hands-on (–off!) opportunity for young scientists DT CSC RPCs High eta RPC gas studies RPCs consolidation GEM

10. Consolidation – gas mixtures • GWPs - Global Warming Potentials http://en.wikipedia.org/wiki/List_of_refrigerants • SF6 is 23900; C2H2F4 is 1100, CF4 is 6500, other fluorocarbons typically ~5000-10000 • Fluorocarbons to be ruled out in the EU after 2017 • RPC gases • Chambers are leaky (500 l/hr), and gas mix C2H2F4 + isoC4H10 + SF6 95/4/0.3% • Fluorocarbons have been essential to good operation of RPCs – so a big problem • CF4 for GEMs and CSCs: • GEMs typically 30% CF4 for optimal timing, but not essential when in conjunction with CSC • CSC contains ~4% of CF4 for anti-aging, little leakage, closed loop gas system and recuperation (but not 100%) • CERN can get EU derogation as a scientific institution, but will substantially reduce global warming components. What about gas availability >2017? • For GEMs we will define the baseline without use of CF4 • Open question: do we need an anti-aging gas R&D for CSC? Not anticipated 5→8 ns

11. Consolidation – L1 trigger latency • “Old” CSC cathode front-end boards (CFEB) include switched capacitor arrays with 96 cells x 50 ns. These precious cells are used: • Before a “pretrigger” based on pattern of hits in the 6-layer chambers • After each pretrigger but before L1A, store 8 cells (follow fairly slow front-end signal for low noise / high precision) • Curves on right are simulation of the CSC cathode data loss versus L1A latency and rate. Data loss >2% for >10 msec • Cost and effort to replace CFEBs is enormous: 13.8 MChF and *12* months (AL) full-time use of the crane 10 msec 1 MHz • Noted this week that Tracker FE limit is 12.5 msec: will Track Trigger electronics (FPGA or AM solutions) push us as high as that value? Hope not… • What is CSC situation at that latency? Is the data loss random, or not?

12. New muon detector R&D • GEM detectors (proposed for GE1/1, GE2/1, and ME0 • Chambers: well-advanced in context of GE1/1 • Front-end electronics: VFAT3 needed for CMS and under design • Back-end, DAQ, and trigger electronics R&D: under development for 40o GE1/1 slice test installed in YETS 2016 • Slice test is a natural focus for 2014-2016 R&D • Building 904 combined CSC-GE1/1 test stand is a natural place for tests GE1/1 slice test YETS 2016 VFAT3

13. New muon detectors: RE3/1 and RE4/1 • Need iRPC (Improved RPC) detectors • Modest 2-4 rate capability improvement factor is sufficient, easily within reach • Using low-noise ATLAS-developed electronics • Using low-resistivity selection of existing bakelite panels • Straightforward build of RE3/1, RE4/1 now seems acceptable • No clear physics motivation yet for ~100 ps resolution Glass RPC multigap • Link to tracks that point at correct vertex • Would need R&D for fast CMS electronics • Need to check links compatible with CSC Track Finder upgrade New RPC electronics

14. Muon simulation for Phase 2 upgrade • New detectors now implemented • Reconstruction software development beginning • Physics gains being quantified • More attention needed for neutron and other background rates: • Comparisons of data (CSC, RPC, DT) hit rates versus FLUKA and GEANT • L1 trigger situation well understood for GE1/1 addition to CSC • Trigger less well understood for Phase 2 era with the Track Trigger functional • E.g. how good is high-eta efficiency? • Is high-eta TT simulation stable? • Muon system pointing accuracy needed? ME-0 ME-1/1