Analysis of Oct. 04 Test Beam RPC Data Jay Hauser, Martin von der Mey University of California Los Angeles

RPCs in Test Beam m- RE2, RE3 behind RE1 on ME1/2 ME3/2 ME2/2 ME1/1 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 13 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: Analysis 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

Internal RPC BXN diff BXN difference for consecutive RPC data arriving at TMB Always incrementing by 1.

No CRC errors for TMB/ALCT ALCT CRC TMB CRC

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? Orbit Emu BX RPC BX Emu starts (mod16) RPC starts (mod16) Difference (mod16) 1 0-923 2 924-1847 12 3 1848-2771 8 4 0-791, 792-923 2772-3563, 0-131 0, 8 4, 0 4, 8 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

Test clock sent to TMB Inverted RPC clock sent to TMB (Runs=553,554)

Reset with SPS Orbit Better agreement (run=563) Still issues to understand

Beam Spot Size Data triggered by SP covers roughly 30x30 cm (Scintillators are 10x10 cm) Key ½-Strip Key Wire Group Key ½-Strip

RPC configuration Run 562 (Wires 0-11) Run 548 (Wires 9-20)

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 RPC Pad Key ½-Strip

RE1 Efficiency Within Fiducial Region Unsure exactly where pads are, so plot efficiency versus CSC wire group This RPC chamber fairly efficient Key Wire Group

RE2 Pad Data Quality Same comparison Active part of chamber appears far from beam centerlow statistics Fiducial region: select half-strips 10-50 Key ½-Strip RPC Pad

RE2 Efficiency Within Fiducial Region This RPC chamber not so efficient Key Wire Group

RE3 Pad Data Quality Same comparisons Fiducial region: select half-strips 80-115 Key ½-Strip RPC Pad

RE3 Efficiency Within Fiducial Region RE3 efficiency reaches a high value, but is not flat with wire number Key Wire Group

RPC timing versus TMB RE2 RE3 RE1

RPC versus ALCT Timing RE3 RE2 RE1 First RPC hit per chamber: RE1, RE2 all in one BX RE3 not as good Note RE1 later by 1 BX RE3 RE2 RE1

RPC Afterpulsing? RE2 RE3 RE1 Number of time bins per chamber per event RE1 and RE2 good, RE3 shows considerable after-pulsing: RE2 RE3 RE1

RPC Pads Hit Pads hit per event (summed over time bins) All look okay (RE1 slightly more pads) RE3 RE2 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?