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Feedback from LAV for the technical run data

Feedback from LAV for the technical run data . T. Spadaro. Run conditions - summary. Running with LAV stations 1 and 2: 1 channel / 320 could not be switched on (HV connector problem at flange) 1 channel / 320 frequently tripping (divider current not stable)

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Feedback from LAV for the technical run data

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  1. Feedback from LAV for the technical run data T. Spadaro

  2. Run conditions - summary Running with LAV stations 1 and 2: 1 channel / 320 could not be switched on (HV connector problem at flange) 1 channel / 320 frequently tripping (divider current not stable) 7 electronics channels/640 were noisy and masked for the DAQ 6 electronics channels/640 masked offline (low-threshold channels) FEE boards operated with 10 (20) mV low (high) thresholds Channel-by-channel thresholds determination takes into account offsets measured while test-benching each comparator Had to fix a number of problems for LAV station 3: • HV bin, TEL62, ... • TEL62 JTAG chain configuration • LAV3 insertion in DAQ was not possible until the very end • Only few runs with LAV3 in High-statistics muon runs of uttermost importance (#319 and 320) acquired Wed 27/11 • 9.5 M Events triggered on a total of 400 bursts • Particularly useful for time resolution studies Studies of hit rate frequency in various configurations: pencil beam, low-intensity K12full, etc. Photon Veto WG

  3. Muon-track clustering Simple topological clustering algorithm to group adjacent fired blocks If at least 3 contiguous blocks are found, form a cluster • Cluster shape information comparing Total number of blocks in the cluster with number of fired layers • Select as muonsthose with 1 and only 1 block fired per layer Number of cells Muon run – Clusters in station 1 Kaon run – Clusters in station 1 Number of blocks Number of fired layers Number of fired layers Photon Veto WG

  4. Muon-track clustering • Count a total of~350 k clusters with 3 or more blocks fired on 9.5MEvts • 180 k in station 1 • 140 k in station 2 • 30 k intra-station (1 and 2) Intra-station clusters Clusters in Station 2 Number of cells Number of fired layers Number of fired layers Photon Veto WG

  5. Analysis of block times • Evaluate resolution by comparing leading time of each block with that of downstream block, using high thresholds • DT21 = T(leading; high; block 2) - T(leading; high; block 1) • Correct for time slewing for each block, by subtracting: • Tslew = Vhigh / (Vhigh-Vlow) x [ T(leading; high)-T(leading; low) ] • For the chosen threshold the coefficient is 2 • Plot DT21-Tslew(block2)+Tslew(block1) vsDTslew = T(leading; high)-T(leading; low) <DT – Tslew> (ns) Block 6 layer1-layer0 Station 1 DTslew (ns) Photon Veto WG

  6. Correction of relative time-zeroes • Pattern of correction under study • Difference in cable lengths for a single banana taken into account • Layer by layer pattern at the level of +-1ns to be understood Station 1 Station 2 <DT – Tslew> (ns) layer1-2 layer2-3 layer3-4 layer4-5 Block ID Photon Veto WG

  7. Correction of relative time-zeroes • Residual time offset at the single-channel level with RMS of 500 ps compatible with expected accuracy on cable length and with board-induced T0’s Station 1 Station 2 <DT – Tslew> (ns) layer1-2 layer2-3 layer3-4 layer4-5 Block ID Photon Veto WG

  8. Correction of relative time-zeroes • Subtract T0 at single channel level, study resolution of DT • Expected time reso is s(DT) = 210 ps/sqrt[E1E2/(E1+E2)[GeV]) (Test beam) • For muons, E1,2 = 80 MeVs(DT) = 1.0 ns s(DT – Tslew) (ns) Station 1 Station 2 layer1-2 layer2-3 layer3-4 layer4-5 Block ID Photon Veto WG

  9. Correction of relative time-zeroes • Subtract T0 at single channel level, study resolution of DT • Expected time reso is s(DT) = 210 ps/sqrt[E1E2/(E1+E2)[GeV]) (Test beam) • For muons, E1,2 = 80 MeVs(DT) = 1.0 ns No slewing corrections Photon Veto WG

  10. Correction of relative time-zeroes • Subtract T0 at single channel level, study resolution of DT • Expected time reso is s(DT) = 210 ps/sqrt[E1E2/(E1+E2)[GeV]) (Test beam) • For muons, E1,2 = 80 MeVs(DT) = 1.0 ns No slewing corrections Slewing corrected s(DT) ~ 800 ps Photon Veto WG

  11. Hit rate studies Study of frequency of hits from • dark count • muon halo • Dedicated runs taken with Gianluca the evening/night of 29/11 using random/periodic triggers • no beam, run 359 • pencil beam, first bursts of run 362 • nominal beam with ~1/50 intensity, last part of run 362 • other conditions, runs 364 and 367 Photon Veto WG

  12. Measuring rate of dark count hits For each burst, count: • Probability to find events with at least 1 complete hit for low,high thresholds • Probability to find events with at least 1 complete hit, both low&high thresholds • PLow = 4.1(1) 10-4 • PHigh = 1.2(2) 10-5 • For a 75-ns window: Fdark(low) = 5.5 kHz Fdark(high) = 160 Hz Statistical correlation ~0: Fdark(low)/ch = 17 Hz Fdark(high)/ch = 0.5 Hz Probability (10-3) for LAV1 or LAV2 Burst number Photon Veto WG

  13. Measuring rate of beam-induced hits For each burst, count: • Probability to find events with at least 1 complete hit for low,high thresholds • Probability to find events with at least 1 complete hit, both low&high thresholds Pencil: • PLow = 2.4(2) 10-3 • PHigh = 1.1(1) 10-3 K12Full, Intensity/50: • PLow = 17.5(2) 10-3 • PHigh = 8.3(1) 10-3 • For a 75-ns window &K12: Fbeam(low) = 230 kHz Fbeam(high) = 110 kHz Statistical correlation ~15%: Fbeam(low)/ch = 120 Hz Fbeam(high)/ch = 54 Hz Probability (10-3) for LAV1 or LAV2 K12 full beam, intensity ~ 1/50 of nominal Pencil beam Burst number Photon Veto WG

  14. Measuring rate of beam-induced hits For each burst, count: • Probability to find events with at least 1 complete hit for low,high thresholds • Probability to find events with at least 1 complete hit, both low&high thresholds • Study scaling with I(T10) • Probability in 10-4 units: I(T10) P(low)P(high) 0.1 4.2(6)3.0(5) 0.2-0.3 16.7(7)6.3(4) 1.3-1.5 154(4) 75.9(3) Probability (10-3) for LAV1 or LAV2 I(T10)~1.3-1.5 1011 I(T10)~0.1 1011 I(T10)~0.2-0.3 1011 Burst number Photon Veto WG

  15. Measuring rate of beam-induced hits For each burst, count: • Probability to find events with at least 1 complete hit for low,high thresholds • Probability to find events with at least 1 complete hit, both low&high thresholds • Study scaling with I(T10) • Probability in 10-4 units: I(T10) P(low)P(high) 0.1 4.2(6)3.0(5) 0.2-0.3 16.7(7)6.3(4) 1.3-1.5 154(4) 75.9(3) 9 182.7(8)99.18(6) Probability (10-3) for LAV1 or LAV2 Rates do not appear to scale with I(T10) Burst number Photon Veto WG

  16. Rates: preliminary conclusions Dark rate completely satisfactory, in agreement with lab measurements  When beam on, drastic change not completely explained, in my opinion: • Expected rate induced by beam halo probably too high  • If the muon halo rate with nominal beam on LAV1 is 1.7 MHz... • ...with 1/50 beam intensity, expect 34 KHz, but observe a factor of 4 more (with low threshold) • Statistical correlation of LAV1 and 2 of 15%, while expect 40% (to be checked)  • Obviously, not a showstopper if one can exploit time information while vetoing  • Probability in three, 25-ns trigger slices of a fake veto from a single low-threshold firing block from any station is 1.8% and it would not be possible to veto with a x50 in intensity • Time information (<1ns resolution) would allow veto with few % random vetoes • Considerations for the acquired muon runs  • With nominal intensity, expect on LAV1 1.7 MHz of muons • This figure translates into a probability of 3 10-3 with 1/50 intensity, observe m “tracks” in 2 10-3 • Considerations for a run with K12  (to be checked again) • With nominal intensity, expect on LAV1, 1.13 MHz due to p+m+n • This figure translates into a probability 1.7 10-3 for 1/50 intensity while observe a factor of 10 less Photon Veto WG

  17. Conclusions LAVs 1 and 2 quite smooth during entire technical run • dead/noisy channels are a few • noisy channels not problematic in terms of random veto rate • rate of dark counts under control and in agreement with lab measurements Big effort devoted to collect data including LAV3, not completely successful Time resolution within expectation: • detailed, channel-by-channel thresholds: “nominal” slewing corrections work fine • mutual time difference has a sigma of 800 ps Next steps: • Time correlation of station 1 with station 2 • LAV-CHOD time correlation (bug in reconstruction, working to fix it) • Efficiency studies Photon Veto WG

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