CMS Latency Review, 13th March 2007CSC Trigger 1 Latency and Synchronization update

CMS Latency Review, 13th March 2007CSC Trigger 2 Latency: Sources of numbers 1. previous numbers were measured! u Components individually measured/understood by responsibles* except the CSC-->DT part. l UCLA l RICE l Florida u System measured as a whole during 2003 testbeam u System partially re-measured 2005 at slice-test u System partially re-measured 2006 at MTCC & overall validation vs DT arrival GMT understood. 2. The new numbers presented today reflect well- understood “deltas” from previous estimates

CMS Latency Review, 13th March 2007CSC Trigger 3 (Previous) Chamber + Peripheral Crate Chamber, CFEB, AFEB, ALCT MPC TMB/CLCT Chamber; TOF, AFEB, CFEB, ALCT 10bx Cables (8-14.5m) incl mux /demux 4bx 14bx muon to peripheral crate TMB/CLCT19bx Backplane incl (de)mux 2bx MPC5bx Optical fibers (94m) 2m coil+2m spare 19 bx 45bx peripheral crate to track-finder 14.5m cable 94m optical fibers SP 11m cables to GMT MS SP (using BXA)13bx Backplane incl GTLP conversion 0.5bx MS6bx 11m Cables to GMT2 bx SP+cables(9m)+transition card to DT-TF 8 bx 21.5 bx track-finder crate to GMT 8bx track-finder crate to DT-TF Cathode/Anode Front End Board Cathode/Anode LCT finders Trigger Mother Board Muon Port Card Sector Processor Muon Sorter

CMS Latency Review, 13th March 2007CSC Trigger 4 (previous)..add it up: Chamber --> Peripheral Crate14 bx Peripheral Crate--> Track- finder 45 bx Track-finder --> GMT21.5 bx Total Chamber-->GMT80.5 bx +/- 1 Total Chamber-->DT-TF67 bx +/-1 Critical path

CMS Latency Review, 13th March 2007CSC Trigger 5 CSC  DTTF Critical Path n This path is too slow: u CSC primitives a bit slower than TDR estimate u DTTF a bit slower than TDR estimate u CSC primitives arrive at DTTF at 67 bx u (this path not broken out in the TDR) n Revised estimate using TMB2005 firmware u 64.2 bx CSC primitives arrive at DTTF n New estimate using TMB2007 firmware u 62.2 bx CSC primitives arrive at DTTF

CMS Latency Review, 13th March 2007CSC Trigger 6 (TMB2005) Chamber + Peripheral Crate Chamber, CFEB, AFEB, ALCT MPC TMB/CLCT Chamber; TOF, AFEB, CFEB, ALCT 12bx Cables (8-14.5m) incl mux /demux 3.2bx 15.2bx muon to peripheral crate TMB/CLCT16bx Backplane incl (de)mux 1bx MPC5bx Optical fibers (94m) 2m coil+2m spare 19 bx 41bx peripheral crate to track-finder 14.5m cable 94m optical fibers SP 11m cables to GMT MS SP (using BXA)13bx Backplane incl GTLP conversion 0.5bx MS6bx 11m Cables to GMT2 bx SP+cables(9m)+transition card to DT-TF 8 bx 21.5 bx track-finder crate to GMT 8bx track-finder crate to DT-TF Cathode/Anode Front End Board Cathode/Anode LCT finders Trigger Mother Board Muon Port Card Sector Processor Muon Sorter

CMS Latency Review, 13th March 2007CSC Trigger 7 Revised estimate using TMB2005 firmware n CSC  DTTF total 67  64.2 bx, difference is -2.8 bx n Front-end is +1.2 bx: u -0.8bx because critical path is actually ME4/1, not ME1/1 (longer optical fibers to SP), Skewclear are shorter. u +1.0bx maximum drift delay 3 bx, not 2bx. u +1.0bx because comparator delay to peak of CFEB amplifier output better set at 3 bx, not 2 bx. n TMB processing is -3 bx: u previously waited for ALCT before CLCT started “pretrigger” stage (configuration mistake, i.e. “pilot error”) u 19 bx  16 bx (TDR was 15.5) n TMB  MPC is -1 bx: u previously overestimated backplane propagation as 2 bx

CMS Latency Review, 13th March 2007CSC Trigger 8 New estimate using TMB2007 firmware n CSC  DTTF total 67  62.2 bx, difference is -4.8 bx n TMB processing 16  14 bx: u -1.0 bx in CLCT processing I/O synchronization: input from CFEB save 0.5 bx, output to TMB matching logic with ALCT save 0.5 bx. u -1.0 bx in internal processing of ALCT-CLCT matching.

CMS Latency Review, 13th March 2007CSC Trigger 9 Details:

CMS Latency Review, 13th March 2007CSC Trigger 10 Latency Summary n CSC-TF path: u Previous estimate 80.5 bx u This is reduced to 77.7 bx currently u Reduces to 75.7 bx with new firmware (compare to TDR 78 bx) n CSC  DTTF path: u Previous estimate 67 bx u This is reduced to 64.2 bx currently u Reduces to 62.2 bx with new firmware u No TDR estimate, but DTTF waits for CSC primitives starting at bx 60 (Janos Ero, longer-than-anticipated optical cables)

CMS Latency Review, 13th March 2007CSC Trigger 11 Synchronization spreadsheet update n Spreadsheet: re-ordered plots sensibly and added a “key” to describe all the Excel plots alct_tx vs skewclear (ns)Alct_tx_clock_delay settings (2.2 ns/bin) are seen to be clearly related to the skewclear cable delay (ns), with a slope of -2 and a wrap-around every 12.5ns in Skewclear delay length. alct_tx_clock_delay comparison Same as previous, except plot the alct_tx_clock_delay in units of ns, and plot against 2*(65-skewclear_delay) (ns) and see the slope=1 and wrap-around every 25 ns. The y-intercept is 10 ns.

CMS Latency Review, 13th March 2007CSC Trigger 12 Sync Spreadsheet: updating parameters after “pilot error” fix n L1A timing looks much more sensible

CMS Latency Review, 13th March 2007CSC Trigger 13 Comments n Data taken with various comparator thresholds u Quick look: 12mV best? Would like to verify with DQM and other offline study u Use 12 mV for subsequent studies n Best trigger timing settings? u Data taken with various drift_delays for ALCT and CLCT u Data taken with various comparator delays to peak u Data taken with various “triad persistence” values u NEED information on what happens to trigger efficiencies u Also need to run with new pattern-finding firmware as soon as it’s ready to verify some of the settings.

CMS Latency Review, 13th March 2007CSC Trigger 14 ALCT fine delays n Dayong “test” of analysis: revert to old firmware phases, try diddling fine delays a little, take data and see if he can find the offset. n Also, a few typos to fix (mine) in getting from Misha’s numbers to the XML file. n Otherwise, new TMB clocking phases should result in constant offset in clock time to all ALCTs, should be invisible to cosmic ray data – to verify. n Then, apply Dayong corrections – is relative timing perfect? n I still want to “predict” ALCT fine delays with spreadsheet… just need a few hours analysis time…

CMS Latency Review, 13th March 2007CSC Trigger 15 Comments I n Best trigger timing settings? u 12 mV deemed best comparator threshold, but is it? u Data taken with various drift_delays for ALCT and CLCT u Data taken with various comparator delays to peak u Data taken with various “triad persistence” values u NEED information on what happened to trigger efficiencies n New pattern-finding firmware: u We’d like to verify some of the timing settings (some will change, e.g. pretrigger earlier with 2 layers rather than 4). u Changes to CLCT/TMB emulator code will be needed (Slava).

CMS Latency Review, 13th March 2007CSC Trigger 16 Comments II n TMB qualities: 4-bit = 16 choices: 6 di-strip qualities gone u Can get by for now just using 10 out of 16 qualities u Slava: reassignment of qualities should be intimately connected with accelerator vs. collision muons question. u Nobody thought through accelerator muons all the way: l Tailor ALCT collision patterns specific to chamber? l ALCT accelerator patterns switched on? l What priority do accelerator muons have? (currently TMB  low quality, but people do want accel. muon trigger) l The SP doesn’t yet handle accelerator muons appropriately (horizontal coincidence)