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RPC status. D. Piccolo – LNF INFN. Overview. RPC Hardware status RPC Barrel detector Efficiency from collisions data RPC cluster size RPC timing synch Conclusions. RPC Detector status. Barrel: Dead channels (including Dead chambers): ~0.6/0.8 % Masked channels: ~0.6/0.8 %
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RPC status D. Piccolo – LNF INFN Muon Barrel Workshop - July 5/7 2010
Overview • RPC Hardware status • RPC Barrel detector Efficiency from collisions data • RPC cluster size • RPC timing synch • Conclusions Muon Barrel Workshop - July 5/7 2010
RPC Detector status • Barrel: • Dead channels (including Dead chambers): ~0.6/0.8 % • Masked channels: ~0.6/0.8 % For Analysis we marked the following rolls as problematic • Dead: 11 rolls • Masked: 8 rolls with at least one full chip masked • RPC in Single gap: 10 rolls • Noise rate and Masked strips: • Noise rate is monitored RUN by RUN. • Strips exceeding predefined threshold rates are masked • Part of them can be recovered increasing electronic threshold • Threshold to define a strip noisy has been changed in different periods MuonBarrel Workshop - July5/7 2010
Masking procedures • Several studies to mask nosiy strips: • IntialConservative approach: mask all channels exceeding 10 hz/cm2 (total number of masked channels 2.7 %) • Increasing electronic threshold and total unmasking (total number of masked channels 0.2 %) • Very high noise rate • Mask all channels exceeding 1khz/cm2 (total number of masked strips 0.4 %) • Still few chambers with high noise • At moment masked all channels exceeding 100 hz/cm2 (total number of masked channel 0.8 %) Muon Barrel Workshop - July 5/7 2010
RPC Detector Performance:Data selection • RPC efficiency calculation is based since CRAFT period on the extrapolation of DT/CSC segments on the RPC plane. • For each extrapolation on a given RPC Roll (2 or 3 rolls per chamber) Efficiency, Cluster size, BX is computed looking at RPCRecHits in a range of +/- 2 strips. • From RUN 135808 ourstaringpointis the MuMonitor PD • Werun a skimtoselecttracker and global muons • Lumi sectionswithconditions (bymeanof JSON file) GOOD and ON for the followingdetectors: CSC, DT, RPC, Tracker • L1 Technical trigger bitsconfiguration: 40 OR 41 AND NOT (36 OR 37 OR 38 OR 39) • Requeston HLT_MinBiasBSC (seededby L1 Technical Trigger bitsconfiguration (32 OR 33 OR 40 OR 41)) • Filteringon goodvertexes (ndof>4, |z|<15, d0<2) and removingtrackerscrapingevents • At leastonetrackermuonwithin |eta| < 1.6 with TM Last Station Ang Tight ID OR • At leastone global muonwithin |eta| < 1.6 with at leastonevalid hit in the outer (muon) track Muon Barrel Workshop - July 5/7 2010
RPC Detector Performance: the method Extrapolate segments used in the muon Reconstruction on the RPC plane For each extrapolation on a given chamber Check if a RPC hit is present at a distance below 2 strips from the impact point Muon Barrel Workshop - July 5/7 2010
Number of extrapolated segments per roll In the Analysis exclude rolls with less than 16 extrapolated segments RUN 135808 - 138751 Statistics is increasing: At moment 57 RB4 Roll with low statistics Muon Barrel Workshop - July 5/7 2010
A single wheel rolls with less than 16 Extrapolated segments Muon Barrel Workshop - July 5/7 2010
Efficiency Distribution Muon Barrel Workshop - July 5/7 2010
Efficiency DistributionGood rolls Muon Barrel Workshop - July 5/7 2010
Average Cluster size distribution Average cluster size Larger than in CRAFT CRAFT08: 9.2 kV Collisions10: HV 9.3 kV Effect of segment slope: Segments with large slopes in internal layers (wrok in progress) Muon Barrel Workshop - July 5/7 2010
RPC Timing • Data selection • Method A:Events selection: • RPC trigger present in event • Important: signal extension on TB (ORing over 3 BX) • Chambers selection: • Tracker track points to the RPC chamber and RPC trigger • ORMethodB:Events selection: • globalMuon present in event • Chambers selection: • globalMuon points to the RPC chamber Initial synch Based on cosmics And cable length MainlyEndcap Timing correction have been applied in different periods According to the statistc increase: The hits are synchronized i.e. assigned to the clock period (BX). One of the synchronization parameters is a position of the synchronization window,which can be adjusted in 0.102 ns steps. Muon Barrel Workshop - July 5/7 2010
RPC Timing Muon Barrel Workshop - July 5/7 2010
Conclusions • Commissioning phase for barrel system is almost done • Timing synch in good shape (less than 0.2 % of hits not in BX 0) • Noise is under control we reached a compromise between number of masked channels and noise rate (1.6 % masked+dead channels) • Still details to be studied on the effect of particular noisy region on trigger • Efficiency for chamber without hardware problems is around 95 % (good agreement with CRAFT09 results and laboratory test) • Cluster size to be better investigated • Correlation with other parameters to spot overvoltaged chambers Muon Barrel Workshop - July 5/7 2010