Notes from FDWG and Planning for DESY

1. Notes from FDWG and Planning for DESY Jay Hauser, UCLA • FDWG (Forward Detector) last Weds. On muons: https://indico.cern.ch/conferenceDisplay.py?confId=243197 • DESY Upgrades Week: https://indico.cern.ch/conferenceDisplay.py?confId=236161

2. (FDWG) Muon Phase 2 Options • Minimal: if endcap calorimeter geometry stays the same: • Calorimeter degradation allowed at some cost to physics capabilities? • Some electronics upgrades, e.g. for L1 trigger latency and rate (19 MChF!) • Possibly add GE2/1, a second station of GEMs • Possibly a rear muon tagger on the “collar” behind HF for |h|>2.4 coverage, improve MET • Possibly replace RE1/2 for improved triggering Additionally, if new endcap calorimeter & tracking coverage to |h|<4.0, choose between: • Add “ME0” station at the back of the present HE • Could cover 2.4<|h|<3.5 or even 1.5<|h|<3.5 • Increase of coverage: “tagging” increases muon acceptance, could reduce MET • Alternate to plan B: add iron muon toroids in place of HF to cover 2.4<|h|<3.5 • Large bending power, not terribly expensive • Additional option to provide trigger

3. A few notes from FDWG • Timescale for decision on endcap calor. replacement: • Tech Coord asked to report on rad dose of HE by ~late summer (feasibility of rework versus full replacement) • A muon back tagger on the collar brought up questions: • It may deflect a lot: need to consider alignment. Track-based may be okay for tagging with no triggering (but HLT?) • There is a lot of iron for 2.4<|h|<3.0, large multiple scattering? • Costing: invite especially electronics experts and work out better prior to DESY • Option B (some kind of ME0 within HE): • Next FDWG meeting (Weds.) will be on particle flow calorimetry – can HE and ME0 use same technology?

4. Also • Phase 2 physics/trigger/simulation meetings heating up • Today: https://indico.cern.ch/conferenceDisplay.py?confId=250552 • Define enhancements for Phase 2 proposals • (Seeking GE1/1 project approval) • Muon aging studies meetings starting • Biweekly on Friday morning ~10:30 or 11, led by Archanaand Armando

5. Organization of talks for DESY • Monday 17:30: muon PU and radiation aging (10’) – suggest Archana • Tuesday parallel sessions on muon 9-11:30 and 11-13:00: • Good amount of time, solicit contributions in various areas: • Physics motivation and simulation • Detector geometries • Detector technologies • Radiation aging • Etc. • See 5-7 registrants from each sub-detector community • Weds. 14:40 muon plenary (50’) • …next slide • Wrap-up talks Friday: supply few slides to Coordinators

6. DESY plenary muon on Weds. Charge: o What is the longevity of the present muon systems - issues for chambers, electronics and trigger o Where enhancements are needed? - options for GEM / GRPC to operate at high rate / extend coverage. Cost? o What studies are needed? What R&D? • Organize by topic and type of detector? • Physics, simulation, trigger, DT, RPC, CSC, GEM… • Too many talks (7 or more) for 50’ • One long talk? Too much to cover.

7. DESY plenary muon on Weds. • Suggestion: four short talks • 15’ Overview of Phase 2 upgrade scenarios • 10’ “Baseline” upgrades necessary for L1 trigger latency, aging studies needed, etc. • 10’ Physics and trigger motivations • 15’ Advanced RPC technologies and GEM technology • Speakers to be decided offline

8. Backup

9. Perspective on Phase 2 muon upgrades • Assuring reliability of current detector is foremost • Good, not perfect: coverage of physics with |h|<2.4 • Good, not perfect: triggering, ID capabilities with 4 stations • Various Phase 1 enhancements are underway or planned – not covered • Plan radiation tests, rate studies – not covered in this talk • New detectors – several promising technologies • Increased rate capability, excellent timing, reasonable cost, … • Discussions initiated by muon community are naturally focused on particular technologies • However, each can be used in different ways within different geometries – n*m choices leads to too many options  • Leads to organizing principle: focus on the geometry and physics first, match the technology to the geometrical application later

10. Muon Option A: Minimal changes if endcap calorimeter geometry fixed • Replace electronics as necessary, for increases in L1 trigger latency and event accept rate • CSC new front end for latency > 6 ms, DT electronics if rate>300 kHz • Cost ~14+5 MChF, respectively • L1 trigger could still make some additions to improve rate or efficiency • GE2/1 was originally proposed, covers 1.65 < |h| < 2.4 • RE1/2 could be replaced with finer-grained detector for trigger, not yet proposed • Muon tagger behind YE4 to cover |h| >2.4, improve MET • Several geometry choices

11. Muon tagger? • In this view it looks possible for 2.4<|h|<3.0, but…

12. Muon tagger: detailed view of HF region • In the more detailed drawing it looks difficult, but…

13. Mounted behind HF • Behind HF, can go from h 2.4 to well beyond 3.5 • Collar and shielding need replacement anyway for Phase 2 LHC • Can install one station for tagging, or several with shielding between them h=2.4

14. Muon Option B:New EE/HE, extend muon coverage to |h|<3.5 • In scenario where Tracker and endcap calorimeter coverage increased to |h|<4.0 • You are the experts on this… • Extend muon coverage to 2.4 < |h| < 3.5 or so • Just behind HE (depends on HE thickness in interaction lengths), or • Make HE a “tracking calorimeter“ where the tail of had shower = muon detector? • Rates are high, but don’t necessarily trigger • Have a high-momentum central track: is there a muon tag nearby?

15. Muon detectors in new endcap • “ME0” At back of present HE • Totally new calorimeter • Existing structure too “hot” • Coverage options: • Minimal (top), maximal (bottom) shown on right • {1.5, 2.4} < |h| < 3.5 • Complement or replace ME1/1 • “Integrated” option • Build all of HE with GEM technology, for example New HE m ME0 Additional EE/HE coverage m ME0

16. Muon detectors behind YE3 • If endcap coverage extended to |h|<4 • HF likely to be replaced? • Something needs to stop and/or measure hadrons with |h|>4 • Little HF? • HF moved closer inside cone? h=2.4 m tagger Jets, underlying events

17. Muon Option C:New EE/HE, add iron muon toroids in place of HF • Similar size, weight as HF, cover 2.4<|h|<3.5 ? • Very good bending, but limited resolution due to multiple scattering • Innermost part, still need shielding of muon detectors • Could be used for triggering if justified by physics Detectors, iron core toroids New HF, shielding New endcap

18. More on iron core toroids SlavaKlyukhin • Coverage |h| 2.39-4.0 • Magnetic field: 1.72-2.17 T depending on radius • Path length: 3 disks x 0.78 m • Bending 4.0-5.1 Tm! • Momentum resolution ~14% up to ~TeV • Steel costs 7.6 MChF each end 382 tons • Other (copper, support, cooling) costs perhaps 0.9 MChF • Electricity 270 kW, annual cost ~140 kChF

19. Summary • In any case, will do electronics upgrades to accommodate L1 trigger changes, etc. • Could be expensive and painful • Option A, current endcap geometry, need to investigate sub-options: • A1: build GE2/1 - try to maintain acceptable trigger in difficult region of 1.8<|h|<2.5 where Track Trigger may be inefficient • A2: build Muon “back tagger” behind HF: physics enhancement of |h|>2.4 • A3: install a RE1/2 replacement to improve trigger for 1.2<|h|<1.6 • Endcap calorimeter replacement? • Decision when? you tell us… • Option B: ME0 detectors at the back of the present HE for coverage, MET, L1 trigger? • Option C: Muon toroid detectors at present position of HF likewise • Next steps: • How to develop the physics and trigger cases, simulation strategy (Alexei’s talk) • Develop detector technology choices and cost estimates (Archana’s talk)

20. Backup

21. Possible discussion topics • Additional trigger rate reduction arguments (e.g. GE2/1) • Details on new HE calorimeters: creating space for muon detectors, etc. • “ME0” within HE: integrated detector technology? • Shielding requirements • Toroids: magnetic forces on them & YE3 • Uses of high-h muons • In tagging mode to increase acceptance, reduce sources of MET • Provide trigger