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Published byLucy Janis Ramsey Modified over 8 years ago
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Status at CERN 8 fills ~500/pb since last Tuesday – ~5.3/fb delivered, ~4.8/fb recorded, … SEU workshop on Friday – Different detectors have different solutions Often requiring VME… No mechanism to do this in CMS… – CSC made the request for periodic Hard Resets First test today with most detectors OFF Next test with all detectors in… or maybe just go for the gusto and do a Hard Reset every 15 minutes towards the end of the fill (just to get folks used to it) 18 Oct 2011G. Rakness (UCLA)1
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Looking at special LHC fills… LHC provided two special fills with different conditions – Fill 2186 = “25ns fill” = 25ns bunch spacing with low intensity/bunch (in this talk use run 178003) – Fill 2201 = “high pileup (PU) fill” = 1 colliding bunch with large intensity (in this talk use run 178208) For these fills, CMS configured the trigger differently than “normal” – Different mixtures of zero-bias, jets, muons – Moreover, in the high pile-up fill, the RPC were prefiring (mistake) As well, offline reconstruction of these data was different than normal… – I don’t even know if the 25nsec fill has been reconstructed yet or not… – Thus, for today, we compare plots from Online DQM with those from a normal collision run (run 177875) 18 Oct 2011G. Rakness (UCLA)2
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18 Oct 2011G. Rakness (UCLA) 3 Run 177875 = “Normal” with 50nsec spacing Recall, CSC’s are readout with an L1A-CLCT coincidence in a window (–3bx, +1bx) wide (in order to readout halo muons) Run 178003 = 25nsec spacing With this window, one can easily resolve muons from 3 early and 1 late collisions (total of 5) which do not cause an L1A… The CSC timing data are available, but not yet used in muon reconstruction Run 178208 = high pileup With regards to the timing, the high pileup fill is clean. I guess this means the RPC pre-firing did not affect the online DQM results for CSC… TIMING
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18 Oct 2011G. Rakness (UCLA)4 Run 177875 = “Normal” with 50nsec spacing Run 178003 = 25nsec spacing Run 178208 = high pileup N wires / L1A No striking differences
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18 Oct 2011G. Rakness (UCLA)5 Run 177875 = “Normal” with 50nsec spacing Run 178003 = 25nsec spacing Run 178208 = high pileup N strips / L1A No striking differences
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18 Oct 2011G. Rakness (UCLA)6 Run 177875 = “Normal” with 50nsec spacing Run 178003 = 25nsec spacing Run 178208 = high pileup N RecHits / L1A No striking differences
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18 Oct 2011G. Rakness (UCLA)7 Run 177875 = “Normal” with 50nsec spacing Run 178003 = 25nsec spacing Run 178208 = high pileup N RecHits / segment No striking differences
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Why do the distributions… a)… not look different from each other? – (except for the timing) b)… not look different from a “normal” run? – (except for the timing) 18 Oct 2011G. Rakness (UCLA)8
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CSC’s are an empty detector 18 Oct 20119G. Rakness (UCLA) E. Juska (FNAL) N collisions / crossing ( = “pileup”) N LCT per ME1/1 chamber Integrated over all ME1/1 chambers, there are ~0.5 LCT’s (segments) per crossing when the pileup is ~30…
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All these fills give ~equal “pileup” for CSC Run 177875 = 50ns “normal” fill – N collisions / crossing ~ 14 (see backup slides) – N bunches / L1A = 2 (see page 2) – Total number of LCT’s in ME1/1 per L1A is 0.45 Run 178003 = 25ns fill – N collisions / crossing ~ 7 – N bunches / L1A = 5 – Total number of LCT’s in ME1/1 per L1A is 0.55 Run 178208 = high pileup run – N collisions / crossing ~ 30 – N bunches / L1A = 1 – Total number of LCT’s in ME1/1 per L1A is 0.5 18 Oct 2011G. Rakness (UCLA)10
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Conclusions The combination of (CSC readout conditions bunch spacing bunch intensity) turned out to make the pileup conditions for CSC ~equal for… – The 25nsec fill – The high pileup fill – Normal fills The CSC is essentially an ~empty detector under any LHC conditions – More study is needed to look for effects on, e.g., multiple muons… 18 Oct 2011G. Rakness (UCLA)11
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To do CSCTF DQM instructions into CSC DQM twiki – Must finish this by tomorrow’s Ops+DPG meeting Gas gain corrections FINISH into CMSSW_5_0 – Continue to press Tim to tell me how to organize the overall normalization Make a summary of SEU meeting – Outline plan to follow up Line up DOC’s for 2012 – Who of these can be lined up for DPG work? Operations Management job description to Misha and Evaldas Write CSC Operations overview talk for Madrid – Make practice talk for next Wednesday’s Ops+DPG meeting 18 Oct 2011G. Rakness (UCLA)12
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Backup: How to compute fill quantities Pileup computed with the LHC calculator – http://lpc.web.cern.ch/lpc/lumi.html http://lpc.web.cern.ch/lpc/lumi.html Using fill information from the SuperTable at https://lhc-statistics.web.cern.ch/LHC-Statistics/, namely… https://lhc-statistics.web.cern.ch/LHC-Statistics/ – Emittance – N protons / bunch = (Total number of protons / number of bunches) – * 18 Oct 2011G. Rakness (UCLA)13
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