130 likes | 147 Views
Minimum Bias Trigger. Regina Kwee CERN / Humboldt-Universität zu Berlin. CAT-Tracking Meeting 16.November 2009 , CERN. Overview of Minimum Bias Trigger. L1 components: MBTS, RD0, LUCID, ZDC, BPTX (BCM –not usable for physics) → cover different eta-regions
E N D
Minimum Bias Trigger Regina Kwee CERN / Humboldt-Universität zu Berlin CAT-Tracking Meeting 16.November 2009, CERN
Overview of Minimum Bias Trigger • L1 components: MBTS, RD0, LUCID, ZDC, BPTX (BCM –not usable for physics) → cover different eta-regions details:https://twiki.cern.ch/twiki/bin/view/Atlas/MinbiasTrigger • MBTS • 16 scintillator -counters per side • 2 read-outs (CTP at L1, TileCalat L2 –has a slightlybettersignaltonoiseratio) • RD0 • internalrandomtriggerof CTP • final L1 rate of RD0 isgivenbyprescaleandfixed rate • Zero-Degree-Calorimeter • triggers on neutralsonly • consistsof a EM andhadronicmodule • sitat +/-140 m awayfrom IP Trigger Summary
Overview of Minimum Bias Trigger • HLT Algorithms: suppressempy BC and beam-backgroundevents L2 : Mbts-Verify, SpacePointCounter, TrtHitCounter EF: Standard NewTrackingInsideOut-sequence (onlysilicon) withminPt = 200 MeV+ TrackCounter • SpacePointCounterat L2 • Fex: retrieves L2 spacepointsforpixelandsctfromOnlineSpacePointProvider (zerosuppressed). Checks fornoisymodules. • Hypo: apply a ToTcut on pixelclusters, candecide on total numberofpix/sctspacepoints, can also run in „fwd-mode“ (requiring a minimum in theendcaps) • Mbts-Verifyat L2 • Fex:MBTSisread-out via standardTile-Cal-PMTs • Hypo: confirms L1 decision. Can usetiminginformationtoreject beam-backgroundevents. Trigger Summary
Overview of Minimum Bias Trigger • HLT Algorithms: suppressempy BC and beam-backgroundevents L2 : Mbts-Verify, SpacePointCounter, TrtHitCounter EF: Standard NewTrackingInsideOut-sequence (onlysilicon) withminPt = 200 MeV+ TrackCounter • TrtHitCounterat L2 • Fex: retrievesTrt RDOs • Hypo: applyToTcutanddecide on a minimumhits in oneoftheendcapsor on the total numberofremaining RDOs • TrackCounterat EF • Fex: retrievesoutputofTrigAmbiguitySolverfromStandard NewTrackingInsideOut-sequence • Hypo: countssilicontrackswithin |z0| = 200 mm Trigger Summary
Trigger Menu • mainphysicstriggersfor 1E31 menu(https://twiki.cern.ch/twiki/bin/view/Atlas/L31TriggerMenu#Minimum_Bias) • supportingtriggersforefficiencymeasurements Trigger Summary
900 GeV Menu • all minbiastriggerarebeingrunat P1 forcosmicdata-taking, but for 900 GeVcollisionphase HLT issupposedtobe OFF. • fordetailsofminbiastriggerevolution, see: https://twiki.cern.ch/twiki/bin/view/Atlas/MinbiasTriggerMenu • L1_MBTS_2 will beANDedwiththe BPTX OR (beam pick-up) and will selectany halo from un-paired bunches, is main physics trigger • LUCID selectedoverlaplarglywith MBTS_2 selectedevents. • Will use LUCID and ZDC ratherfor commissioningdetectorsand triggersthanforphysicsselection. 900 GeV private production (by W. Bell), numbers from S. Ferrag Trigger Summary
Trigger Efficiencies Trigger acceptencefor 10 TeVdataandnew ATLAS tune (mc09) e456_s596_s582_r813(sofartheonlycompleteanalysis sample forminbiasstudies, but tracksarebadandtriggersaremissing) Trigger Summary
e456_s596_s582_r813(badtracks) • singleand double diffractiveeventsaremuchmoredistinctthan in mc08 data (wheretracksandhitswereverysimilarlydistributed) Trigger Summary
Trigger in Official 900 GeVdata (ndiff) mc09_900GeV.105001.pythia_minbias.recon.ESD.e466_s604_s582_d216_r833_tid095319 Trigger Summary
MB Trigger In-/Exclusitivity mc09_900GeV.105001.pythia_minbias.recon.ESD.e466_s604_s582_d216_r833_tid095 Trigger Summary
Ongoing Activities • minbiasperformancestudiestomeasuretriggerbiasesandefficiencies (with Andrea Messina and David Berge) • luminositymeasurements (Andrea): • Andrea showedthatthe MBTS hitsare sensitive tothenumberofinteractionsμ in a BC. μisdirectly proportional to L/σ. • motivationistohaveredundancyofluminositymeasurements • includeluminositymeasurementfrom MBTS in the DB • regularreports in theluminositytaskforce, seeeg. http://indicobeta.cern.ch/getFile.py/access?contribId=1&resId=0&materialId=slides&confId=74032 Trigger Summary
ANNOUNCMENT • Mark Stocktion kindly agreed to give a tutorial on the Atlantis Event Display with emhasis on minbias aspects • meant for minbias trigger and tracking community (primarily minbias, others are welcome too). • aim is to get analyse first beam data“by eye“ to get an idea how the events look like which we trigger on • program: • produce atlantis xml files from beamgas, halos, cosmic data, MC inelastics • get trigger/reconstruction information • save atlantis configuration, how to producepictures in one go
ATLANTIS tutorial • Place: Room A • Date : Monday, 16.Nov.2009 • Time: have the room from 17:30-20:00