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Analysis of Oct. 04 Test Beam RPC Data. Jay Hauser, Martin von der Mey University of California Los Angeles. RPCs in Test Beam. 1 RE1/2 (call it RE1) 2 free-standing (call them RE2, RE3) Readout info for experts only: RPC0 RE1 RPC3 RE2 RPC2 RE3. RE2, RE3 behind. RE1 on ME1/2.
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Analysis of Oct. 04 Test Beam RPC Data • Jay Hauser, Martin von der Mey • University of California Los Angeles
RPCs in Test Beam • 1 RE1/2 (call it RE1) • 2 free-standing (call them RE2, RE3) • Readout info for experts only: • RPC0 RE1 • RPC3 RE2 • RPC2 RE3 • RE2, RE3 behind • RE1 on ME1/2 • ME3/2 • ME2/2 • ME1/1 m-
Link Board to RAT Board Setup • RAT receives 4 cables, one from each RPC chamber • Cables 0, 1, 2 were connected • Appears that phasing RAT-TMB incorrect, so that 0 2 and 13 in readout • N.B. RE1 seems the healthiest chamber
RPC-RAT Interface • RAT receives 4 cables with 20 pairs each (3 cables active at test beam) • For each cable/RPC chamber implemented: • 4 bits of bunch crossing • 12 bits of RPC pad data • 1 clock • (FYI CMS specification is 16 pads, 2 bx, 1 clock, 1 GND) • New full-size backplane was used
Data Conditions • Run conditions: • Link boards arrived Saturday p.m., run ended Sunday evening • Runs 535-548 have RPC data. • Data triggered by Sector Processor, not scintillators • Beam spot roughly 30 cm each dimension • RAT latches bits on falling edge of 40 MHz clock where they are stable • Analysis conditions: • Comparison CSC chamber always ME3/2 - part of SP trigger (ALCT&CLCT required) • Run 548 taken Sunday. • Corrupted RPC events not included • Seen at 1% level • Symptom: as if no RPC cables connected to RAT (?)
TMB Bunch Crossings - Data • Flat Distribution seen 0-15 (4 bits): • N.B. no ALCT or TMB data transmission errors (CRC check) seen in these runs
RPC Bunch Crossings - Expectations • Emu electronics used orbit=924 bx, RPC used orbit=3564 bx • These are incommensurate. • What are lowest 4 bits if synch is perfect? • Therefore, expect various differences in jumps of 4 bx • In general, there can also be an offset due to time delay of BX0
RPC Bunch Crossings - Data • TMB vs RPC see perfect agreement with expectations. • At least, ALCT/CLCT bx reset/bx0 protocol = Link board protocol
RPC BX from different RPC Chambers? • Nice diagonals, but offsets (2, 7 bx) due either to TTCrx offset or reset timing at Link board
Key ½-Strip Key Wire Group Key ½-Strip Beam Spot Size • Data triggered by SP covers roughly 30x30 cm • (Scintillators are 10x10 cm)
Key ½-Strip RPC Pad RE1 Pad Data Quality • Compare ME3/2 (rear chamber) CLCT key half-strips (not strips) to RE1 pad (vertical dimension) • Good position agreement (one dead pad) • Modest RPC efficiency within readout region • Fiducial region for RE1 select half-strips 65-100
Key Wire Group RE1 Efficiency Within Fiducial Region • Unsure exactly where pads are, so plot efficiency versus CSC wire group • This RPC chamber fairly efficient
Key ½-Strip RPC Pad RE2 Pad Data Quality • Same comparison • Active part of chamber appears far from beam centerlow statistics • Fiducial region: select half-strips 10-50
Key Wire Group RE2 Efficiency Within Fiducial Region • This RPC chamber not so efficient
Key ½-Strip RPC Pad RE3 Pad Data Quality • Same comparisons • Fiducial region: select half-strips 80-115
Key Wire Group RE3 Efficiency Within Fiducial Region • RE3 efficiency reaches a high value, but is not flat with wire number
RE2 RE3 RE1 RPC versus ALCT Timing • First RPC hit per chamber: • RE1, RE2 all in one BX • RE3 not as good • Note RE1 later by 1 BX
RE2 RE3 RE1 RPC Afterpulsing? • Number of time bins per chamber per event • RE1 and RE2 good, RE3 shows considerable after-pulsing:
RE2 RE3 RPC Pads Hit • Pads hit per event (summed over time bins) • All look okay (RE1 slightly more pads) RE1
Summary • RPC Link Board to RAT-TMB data transmission worked well • RPC pads well correlated to CSC position • Timing looks strange on one RPC chamber • RPC efficiency hard to study • Instrumented region was small • Gas was not optimal due to safety concerns • Will be useful to do simultaneous analysis of RPC data taken through Link board readout – is it possible to double-check? • N.B. time for doing tests was way too short. Is there some way to set up a cosmic ray test bench for a longer time?