1 / 7

Reviews galore

Reviews galore. Yesterday: GEM proposal review (more later) Mon-Tues Feb 25&26: Workshop #2 on CSC Planning for LS1 Created agenda at https:// indico.cern.ch/conferenceDisplay.py?confId=236792 Weds-Thurs Feb 27&28: CERN review of ME1/1 and ME4/2 projects

garima
Télécharger la présentation

Reviews galore

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Reviews galore • Yesterday: GEM proposal review (more later) • Mon-Tues Feb 25&26: Workshop #2 on CSC Planning for LS1 • Created agenda at https://indico.cern.ch/conferenceDisplay.py?confId=236792 • Weds-Thurs Feb 27&28: CERN review of ME1/1 and ME4/2 projects • Agenda for first day at https://indico.cern.ch/conferenceDisplay.py?confId=235558 • Agenda for 2nd day under development (Loveless) • Meanwhile: ARC review for Z+jets at 7 TeV

  2. GEM review: motivation • From 2 weeks ago •  Lever arm in 1/1 station increased 2.5-5.0x •  Resolution allowed by current 16:1 ganging for trigger is ~8 mrad, need at least 4x finer (see below) for trigger Full Geant Simulation Df(CSC-GEM)~ 3 mrad Dx ~6 mm pT=20 GeV pT=5 GeV

  3. Forward trigger RATE • Muon momentum from stub positions • DfXY=f(ME-X)-f(ME-Y) • Measurement driven by Df12 • ME-1/1 defines the accuracy • Least scattering and B field • “Flattening”: mismeasured soft muons • Soft muons scattering in the absorber can occasionally have stubs align like for a high pt muon • Rare but there are lots of them! • Tails in L1 momentum resolution • A fundamental issue with no solution • At some point you just hit the wall • Likely the last improvement, as the new TF has likely reached that wall CMS DAQ TDR New CSCTF: rate reduction factor

  4. Potential solutions View from the top of CMS down • Removing tails in L1 muon momentum resolution to control trigger rate cannot be done without a second detector: • Match to inner tracker tracks at L1 • Great but unavailable until LS3 • Can a second muon system improve momentum resolution? • It could if we can measure and use the “bending angle” • Used in the Barrel; CSCs are too thin to see the bend on its own • A new detector in YE-1/1 (the least affected by scattering and largest magnetic field) • Increase “lever arm” & have enough spatial resolution to measure bending angle • Physical constraints allow a maximum lever arm of Dz=30-50 cm in YE-1/1 • The new detector needs ~2-3 mmor better trigger resolution to effectively discriminate 5-10 GeVmuons from 20+ GeV ones

  5. Bending angle: simulation Df(CSC-GEM)~ 4 mrad Dx ~8 mm “Close” chamber pairs “Far” chamber pairs pT=20 GeV pT=5 GeV • GEM-CSC bending angle measurement using GEANT simulation: • Muons with PT=5 and PT=20 GeV • Digi level (full GEM granularity) – this is what HLT Level-2 can do • Slight deterioration due to discretization and resolution effects, but still strong discrimination

  6. Effect on the trigger rate • Extremely preliminary • Accounts for some but not all CSC TF improvements • An explicit cut on the CSC-GEM bending angle to be ~100% efficient at and above 20 GeV • In real case we will send “bending angle pattern” • Dramatic decrease in ratio towards low pt due to that cut • Ratio will flatten once bending patterns for pT ranges are defined • The plot is less than 24 hours old, so take it as a promise that the final plot is on the way Super Preliminary Super Preliminary

  7. Implementation • Use 4 of 5 unused fibers in ME1/1 bundle of 12 • Feeds directly into TMB • GEM group proposed to put 2 chambers in place during LS1 • Front-end electronics not final • Trigger 4-16x worse segmentation than final electronics • Readout system cobbled together • DAQ electronics effort thin • New suggestion: • Put a “slice test” with 3, 6, or 9 GEM chambers in during long YETS between 2016-2017 (when new pixels installed). • Could use final electronics • (Time to develop good TMB firmware) • Transparencies for front end at https://www.dropbox.com/s/6hfyzy935sr0jy1/Aspell_LS2_Electronics.pdf and FPGA/DAQ at https://www.dropbox.com/s/sftbtist9oxgky8/Gilles_2013-02-GEM-Review.pdf

More Related