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MTR review June 13th, 2012

MTR review June 13th, 2012. Muon Trigger Status. All RPC detectors operating smoothly with low and stable dark current and rate one RPC with 20% gaz leak : broken gas connector ? => will be checked during the next TS Front-End Electronics only ~10 (/21K) bad channels

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MTR review June 13th, 2012

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  1. MTR reviewJune 13th, 2012

  2. Muon Trigger Status • All RPC detectors operating smoothly with low and stable dark current and rate • one RPC with 20% gaz leak : broken gas connector ? • => will be checked during the next TS • Front-End Electronics • only ~10 (/21K) bad channels • Muon Trigger Decision Electronics • Fully operational • 0MLL (Like-Sign Low Pt) : very low count rate seen from CTP counter but count rate OK from Muon Trigger scalers => to be checked during next TS • Position of all the detector half planes checked with survey group and fine tuned (when needed) during the last winter shutdown • need full campaign of survey/photogrammetryfor LS1

  3. What are the current hardware problems that create data taking inefficiencies and what is the planned follow up ? • Recent problem with DARC-Right readout card (reading out one half of the Muon Trigger) • DARC-R card malfunctioning since May 22nd • !! Preliminary diagnostic, wo cavern access !! • DARC-R replaced with a spare on first access occasion (June 1st) • The spare DARC is also having problems • The problem is the communication with the LDC through the DDL : indeed, the VME readout of the DARC indicates correct data, internally (!). • Unsuccessful attempts to fix it by software (reconfiguration of the DARC robot-clock ) • -> need longer access which is scheduled during the next TS for a more accurate diagnostic of the problem. Experts will be present. • 2 other DARC spares are being prepared in Subatech for the next TS • News from June 12th : new access to cavern, plug/unplug DARC /SIU • Readout RECOVERED ! • Mission of experts during next TS maintained however

  4. Which are the rate limits of your detector and what are the detailed reasons ? • Rate limit from detector performance • In beam test we measured unaffected performance up to about • 80 hit/s/cm2-> set a rate limit of 50 hit/s/cm2 , corresponding to about 800 kHz of pp interaction rate (for the most irradiated RPC) • Rate limit from ageing • Ageing tests have shown unaffected performance up to • 550 Mhit/cm2, corresponding to 3000 h at 50 hit/s/cm2 • -> Current limit of 250 kHz is chosen based on cost/benefit analysis (don’t run in very unfavourable signal/background conditions)

  5. p-A: how can your subdetector deal with equivalent proton rates of 210 to 700 kHz? Average RPC counting rate vs pp luminosity Extrapolation of the average counting rate to 200 kHz: ~ 5 hit/s/cm2 Extrapolation of the average counting rate to 700 kHz: ~17 hit/s/cm2 Most irradiated RPC gets about 3 times the average rate => ~50 hit/s/cm2 p-A -> running at 50 hit/s/cm2 (<-> 700 kHz pp) should be possible V0and rate 50 kHz 100 kHz

  6. LS1 •  Review of the gas system -- are there upgrades planned ? • Not for LS1 • Can we reduce the gas consumption ? • in the next Technical Stop we will reduce the gas flow from 160 l/h to 130 l/h. Further decrease is not recommended

  7. LS1 • Are there new cable to be pulled between the CRs and the cavern for your subdetector ? • No • What kind of hardware interventions are planned ? • Ordinary FEE and gas tightness maintenance • Replacement of a few RPCs if needed • Full campaign of survey and photogrammetry

  8. LS1 • What kind of hardware interventions are planned ? - lateral extension of SAA3 shielding (ALICE TC) 2011 (before upper part extension) 2012 (after upper part extension)

  9. LS1 •  Is there any change or extension of hardware foreseen that would need • extension of the DCS (in particular more PCs) -> No • installation of additional network outlets -> No • additional rack space -> No • Are the currently implemented hardware interlocks sufficient to protect your subdetector, or is a review/modification/extension required.-> Currently implemented interlocks are sufficient

  10. Spares

  11. p-A: how can your subdetector deal with equivalent proton rates of 210 to 700 kHz? p-A: most irradiated RPC gets about 3 times the average rate, i.e. ~ 50 hit/s/cm2 in the worst case (700 kHz equivalent pp rate) Filled squares: cosmic ray efficiency with no irradiation Open squares: cosmic ray efficiency with 60 hit/s/cm2 irradiation from GIF A decrease of the efficiency was observed for rates above 100 hit/s/cm2 P-A -> running at 50 hit/s/cm2 (<-> 700 kHz pp) should be possible without efficiency loss

  12. Half plane surveyfromJanuary 2012 Example : position of MT11 RPCs wrt nominal MT11 outside MT11 inside Z Y X • Position of all MTR half planes measured with theodolite • Most RPCs within ±3 mm in Y and Z (strict req. is ±2 mm) , wrt nominal position • Some half planes position fine tuned in Y direction within few mm

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