Timing/Synchronization Status Greg Rakness University of California, Los Angeles CMS EMu-ME1/1 Meeting CMS Week 11 December 2007 Synchronization parameter predictions—update Trigger configurations underground Proposal for how to synchronize during commissioning Some details on ME1/1 chambers 11 Dec 2007 G. Rakness (UCLA)

Synchronization Predictions Update Recall: Initial xml files generated by c++ code for all 468 chambers Prediction of synchronization parameters based on cable/fiber lengths Description at https://twiki.cern.ch/twiki/bin/view/CMS/CSCTimingProgram New: Now includes ALL AFEB fine delays and thresholds (N. Terentiev, CMU; A. Korytov, UF; M. Ignatenko, UCLA) For detailed description, see Nikolai’s talk at http://indico.cern.ch/conferenceDisplay.py?confId=21933 When available, based on values from latest SX5 tests. When not available, ISR or FAST site tests… For ME1/1: Delay settings calculated from cable lengths, using constant DAC/nsec conversion (“should be remeasured ASAP”) No time-of-flight correction included 11 Dec 2007 G. Rakness (UCLA)

Synchronization Predictions (cont.) New: Now has explicit latency for each component (TMB, ALCT, Global Trigger, etc.) For example, if L1A latency changes, change one number in code; if ALCT firmware changes, change one (other) number in code… To be done: Tie L1A-latency for CFEB to L1A-latency for ALCT/TMB Implement Time-Of-Flight correction Make latency change algorithms work on measured parameters (from xml files), too 11 Dec 2007 G. Rakness (UCLA)

CSC Trigger Configurations Summary of email discussion: For global data runs, LHC pattern trigger most useful (best for Track Finder, DPG work, emulator)… For other purposes, these rates are too low… Trigger primitive configurations available: LHC pattern trigger  muon pointing to IP Plusses: real muons trigger nominal pattern Minuses: 0.3 Hz/chamber (for TS1 in USX55) Layer trigger  CSC ~ scintillator paddles Plusses: expect ~ 6 * LHC pattern rate Minuses: no wiregroup nor ½-strip info in trigger; steep tracks; different ALCT firmware needed “Radioactive” trigger  natural radioactivity in and around chamber Plusses: expect ~ 100 * LHC pattern rate Minuses: not real muons Testpulse trigger  pulse test strip Plusses: no HV needed; adjustable rate Minuses: strange “muons” in CFEB data; no drift time; no time-of-flight 11 Dec 2007 G. Rakness (UCLA)

Compare Testpulse vs. Cosmic Ray Timing DQM results of ALCT-CLCT matching for cosmic rays with LHC pattern trigger using sync parameters from testpulsing centered at 3.5 Distribution of mean values from all chambers: Worst case: ME+2/1/2 (Run 071204_115437) Window size = 7 Best value Synchronization values from high rate triggers consistent with values for LHC pattern trigger (with wide windows) 11 Dec 2007 G. Rakness (UCLA)

Proposed Path to Synchronization Open up coincidence windows Start with parameter predictions from cable lengths Synchronize each chamber by itself online with radioactive trigger Take a long data run with LHC pattern trigger on cosmic rays Use DQM results and Sector Processor analysis to line up: LCTs from different chambers at the Sector Processor ALCT with CLCT for each chamber Adjustment of L1A receipt delays for DAQ readout Take another run: data will show if trigger path is synchronized May need to fine tune L1A receipt delays for DAQ readout… (N.B. only tools available are online scans…) Shrink coincidence windows (eventually) 11 Dec 2007 G. Rakness (UCLA)

Proposed Path to Synchronization: Open Questions… How long of runs are needed for LCT alignment at Sector Processor? Use layer trigger to increase coincidence rate? Possible to add information to data headers to monitor DAQ synchronization directly? L1A position in matching window for TMB, ALCT, CFEB DAV scopes in DAQ readout 11 Dec 2007 G. Rakness (UCLA)

Emulator Based Rate Projections (D. Wang, UF) Method: Full simulation, combined with proper normalization factors for the samples, can estimate cosmic rays underground for all CSCs Standard CMS cosmic simulation samples Generator: CMSCGEN Total rates of cosmic muon in CMS underground: 650Hz (From K. Hoepfner) Preliminary results for ME1: Ring 1: 0.06-0.1Hz Ring 2: ~0.3Hz Ring 3: ~0.4Hz Preliminary results for ME2, 3, 4: Ring 1: ~0.4Hz Ring 2: ~1.0Hz Trigger Sector distributions of cosmic rays at bottom right +Z -Z 11 Dec 2007 G. Rakness (UCLA)

Synchronization Issues for ME1/1 Synchronization of ME1/1 with full system limited to MTCC Essential differences between ME1/1 and other chambers include… Orientation of chambers require four types of ALCT firmware (forward/backward + plus/minus endcap) Type of firmware to be loaded is specified in xml file At configuration, direct check of ALCT firmware version read from fast control FPGA register One type of slow control firmware For AFEB fine delays and thresholds, AFEB  ALCT input channel mapping will require reversal of loading for 2 of the 4 types of ALCT No staggering of strips VME register on TMB has bit “csc_stagger” to account for non-staggering of ME1/1 strips No teststrip Will need to use radioactive trigger to synchronize 11 Dec 2007 G. Rakness (UCLA)

Backup slides… 11 Dec 2007 G. Rakness (UCLA)

Cosmic rays above and below ground… Going from above ground (SX5) to 100m below ground (USX55)… Changes to muon spectra addressed in L.N. Bogdanova, et al., Phys. Atom. Nucl. 69 (2006) 1293; arXiv:nucl-ex/0601019v1  Angular distribution of muons similar under 100m solid rock as on surface… [Will be modified due to shaft… i.e., minus end will see more vertical muons]  Rate in USX55 is ~1% rate in SX5… Q: How to increase the trigger rate to synchronize downstairs? A: Expand the scope of CSC triggers beyond “normal” LHC muons… 11 Dec 2007 G. Rakness (UCLA)

New n-Layer Trigger Concept: trigger on any muon which traverses the chambers… CSCs  large scintillators with wider angular acceptance Configuration: ALCT and CLCT layer fire on any hit within a layer Require minimum number of layers for ALCT (CLCT) trigger (same as for pattern trigger) Trigger on ALCT*CLCT match Rate  6x LHC muon pattern trigger on cosmics Large angular acceptance enables online determination of ALCT and CLCT efficiencies using TMB counters Typical “efficiencies”: ALCT  99.9%, CLCT  99.1% See recent DPG talk by J. Hauser (http://indico.cern.ch/conferenceDisplay.py?confId=21707) 11 Dec 2007 G. Rakness (UCLA)

New Radioactive Trigger Concept: trigger on (low energy ?) particles resulting from radioactivity in and around chambers Configuration: ALCT and CLCT each fire on a single layer normal pattern and n-Layer trigger are identical w.r.t radioactive trigger Trigger on ALCT*CLCT match Rate = 100x LHC muon pattern trigger on cosmics (including cosmic ray “background”) ~95% of CLCT pretriggers match with ALCT Large fraction of real coincidences Uniform distribution in layer and position Sensitive to single hot channels in ALCT and CLCT Need hot channel mask… 11 Dec 2007 G. Rakness (UCLA)

CSC Test Strip Pulsing Recall: CSCs equipped with test strip (= extra cathode strip) which can be pulsed by TTC command (ADB sync) through CCB  ALCT Pulsed test strip induces signal synchronously on both anode wiregroups and on cathode strips in the CSC “waveguide”… can be used to trace “muon” signals through trigger and DAQ amplitude = 20 di-strip CLCT0 -------- ----- 0 0 1 2 2 88 3 99 4 11 5 17 6 8 7 100 8 0 Components are blind to source of signals (i.e., AFEB, CFEB, ALCT, TMB, DMB…) Two signals are induced for each ADB sync signal, both on leading and rising edge… pulse length = 550 nsec Successfully used to trigger CSCs from Global Trigger in end of September Global Run Number of triggers seen versus distrip for 100 pulses di-strip 0 masked off, since it rings hot when test strip enabled No data beyond di-strip 8 11 Dec 2007 G. Rakness (UCLA)

Fiber lengths from TTC  CCB Differences corrected by CCB TTCrq parameters TTCrxCoarse[Fine]Delay… Setup Avg. (m) Min. (m) Max. (m) MTCC YE+1 150 MTCC YE+2 160 Minus side slice test ME+1 74.1 59.9 83.9 ME+2 91.8 84.0 101.0 ME+3 91.7 83.0 ME+4 98.7 88.0 112.0 In contrast to MTCC, final fiber lengths differ by as much as ~10 bx… Assume these numbers reflect MPC  Sector Processor fiber length differences SP firmware upgrade required to pass ME1 trigger primitives to Drift Tube Track Finder before ME4 arrives to keep CSC off the latency critical path… 11 Dec 2007 G. Rakness (UCLA)