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Underground CSC Synchronization

Underground CSC Synchronization. Would like to be able to synchronize the trigger and DAQ paths of the CSCs to the order of ~1 bx without… cosmic rays LHC beam Pulse CSC teststrips to induce signals on both wires and strips

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Underground CSC Synchronization

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  1. Underground CSC Synchronization • Would like to be able to synchronize the trigger and DAQ paths of the CSCs to the order of ~1 bx without… • cosmic rays • LHC beam • Pulse CSC teststrips to induce signals on both wires and strips • Mask off comparator distrip=0 or distrip=39, depending on routing of teststrip (probably just easier to always mask these off) • (currently) Trigger on “ADB SYNC” command from CCB • Stripmask = 0x3f (all 6 layers enabled) • Trigger invert = 0 G. Rakness (UCLA)

  2. CLCT distrip occupation with teststrip pulsing • Mask on single distrip per layer (straight-line track) • Pulse • Read CLCT0 key ½-strip • Move to next distrip • Repeat for all distrips 100 times amplitude = 20 di-strip CLCT0 -------- ----- 0 0 1 2 2 88 3 99 4 11 5 17 6 8 7 100 8 0 amplitude = 50 di-strip CLCT0 -------- ----- 0 0 1 100 2 99 3 55 4 4 5 13 6 13 7 100 8 0 amplitude = 5 di-strip CLCT0 -------- ----- 0 0 1 0 2 76 3 0 4 0 5 0 6 0 7 98 8 0 ALCT: LCT sent to TMB 0 CLCT: Pretrigger 341 CLCT: Invalid pattern after drift 147 CLCT: TMB matching rejected event 194 TMB: CLCT,ALCT,or both trigger 0 L1A: L1A received 3900 • CLCT more sensitive than ALCT to teststrip pulsing • di-strip 7 is very sensitive (should be masked off?) • CLCT fully firing by amplitude = 20 G. Rakness (UCLA)

  3. Timing of ALCT in CLCT match window • Example relative ALCT-CLCT timing measurement from chamber in building 904, using: • clct_pretrig_thresh = 2 • clct_pattern_thresh = 4 • CCB in FPGA mode for: • ADB_SYNC • L1A Pulse amplitude = 25.0 Pulse teststrip 1000 times on signal ADB_SYNC ALCT in CLCT match window[0] = 0 ALCT in CLCT match window[1] = 0 ALCT in CLCT match window[2] = 561 ALCT in CLCT match window[3] = 439 ALCT in CLCT match window[4] = 0 ALCT in CLCT match window[5] = 0 ALCT in CLCT match window[6] = 0 ALCT in CLCT match window average = 2.4 ALCT: LCT sent to TMB 1562 CLCT: Pretrigger 1100 CLCT: Invalid pattern after drift 52 CLCT: TMB matching rejected event 48 TMB: CLCT,ALCT,or both trigger 1000 L1A: L1A received 2000 L1A: TMB triggered, TMB in L1A window 1000 G. Rakness (UCLA)

  4. Timing of ALCT in CLCT match window • With teststrip pulsing, the CLCT-ALCT relative timing is measured to be within ~1 bx of the relative timing measured with cosmic rays • should be able to use this technique underground to get approximate timing for full trigger and DAQ paths to sufficient accuracy for large windows • ALCT arrives later (or, CLCT arrives earlier), with… • increasing match_trig_alct_delay (alct_delay)  expected • decreasing time of comparison (after passing threshold)  expected • decreasing CLCT drift delay  expected • decreasing testpulse amplitude  ? • No dependence of relative timing on… • number of layers required for pretrigger  expected, since no drift involved • layer or normal pattern finding algorithm  expected,although still not clear why difference between algorithms is seen with cosmic rays… • No matches seen with inverted pulse • operator error since ALCTs and CLCTs were seen in TMB counters? G. Rakness (UCLA)

  5. To do: • Synchronizing CSC by pulsing • Need to send “ADB Async” through the Local Trigger Control (LTC) module • Will take development • Need to make button to enable software pulsing • Easy • All other software “should” work as well as they do for (independent) cosmic rays • Will see… • update CMS software with: • VME registers with respect to latest TMB firmware updates • broadcast ALCT firmware  broadcast TMB firmware now disabled • Request to resurrect ALCT “Fast self-test” (?) • Write talk for TWEPP-07 G. Rakness (UCLA)

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