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Update on HPD Noise Study and Trigger Issues Analysis

This document provides a comprehensive update on the HPD noise study, detailing issues related to fake triggers and their effects on signal integrity. Key points include the identification of noise patterns in single and multi-HPD events, discrepancies in trigger primitives (TP) and ADC (QIE) readings, and the prevalence of fake triggers in various runs, particularly in runs r35672 and r35127. The findings suggest a significant impact of fake triggers on the overall data quality, emphasizing the need for further investigation and potential corrective measures to ensure accurate event reconstruction.

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Update on HPD Noise Study and Trigger Issues Analysis

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  1. Update on HPD noise study Pawel, Dima, Kerem, Numan Richard,Ted, Ellie, Terry, Christian, Pam, Alexander HCAL commissioning Mtg February 23, 2008

  2. Summary of issues: A) fake triggers TPs set on, but no energy in corresponding QIE channels B) HPD noise rate single-HPD events multi-HPD events

  3. TP vs ADC, r35672 Fake triggers ~ 90% of events Good triggers ~ 10% of events

  4. Fake trigger problem ADC and TP in eta-phi space Trigger primitives (TP) Adc (qie) R35127, ev6366, 3d plot

  5. Noise runs: Fake trigger problem A lot of triggers does not have ADC confirmation Problem appears in 4x2 blocks of trigger sections

  6. Eta/Phi distribution of TP>=20 after fake triggers removed Only ADC confirmed TP Occupancy ADC> 20 lin adc counts (~ 4 GeV cut)

  7. TP vs digi mismatch existed also in GREN HCAL Trigger GREN run, HCAL top-and-bottom trigger Run 30205: HCAL trigger only Run 30478: DT+RPC+HCAL trigger 7

  8. Summary: fake trigger issue fake hcal triggers, we mean triggers which do not have matching (correspondence) in qie energy • Qie energy for all hcal towers is consistent with pedestals, event appears to be healthy (proper number of digis reconstructed • Fake TPs appear in blocks 2x4 (in phi x eta). • They apper in proper time bucket. For runs taken on fri-feb15 this was TP(2), for runs taken on wed-feb20 this was TP(3). Earlier bx have no sign of corrupted TPs. • Fake HCAL triggers first noticed in r30205(gren, top-bottom coincidene), • Also present in r35127 (first attempt to take HPDnoise data (fri, feb15) • Also present in r35605 (wed, feb20) • In r35672, almost 90% of triggers were fake. • within run, fake trigger rate is not stable (for r35127, it only started after evt 6000

  9. TP and QIE energy, r35605 (Trig Th = 10 GeV) TP 100 GeV = 500 Lin Qie counts Lin ADC counts Lin ADC counts

  10. TP and QIE energy, r35672, Trig Th = 20 GeV TP :100 GeV = 500 Lin qie counts Lin ADC counts Lin ADC counts Lin ADC counts

  11. Single HPD noise: Event examples

  12. Single HPD noise

  13. Multi-HPD noise: Event examples

  14. Multi-HPD noise

  15. HPD and pixel multiplicity

  16. Single and multi-HPD occupancy Single-HPD noise HB- Single-HPD noise HB+ Multi-HPD noise HB- Multi-HPD noise HB+

  17. Summary: HPD noise HPD noise data taken on wed-feb20: Runs taken with two thresholds: 10 GeV and 20 GeV HBplus, HBminus, HEplus included in the trigger Rates (raw, reported by GT), 1-5kHz at 10 GeV, 10-70Hz for 20 GeV (not clear what real rates are, as we have fake trigger problem) We see two types of events single-HPD noise event (only one HPD shows signs of noise) multi-HPD noise events (two or more events within same RBX show signs of noise HPD multiplicity: 95% are single-HPD noise (at 20 GeV TP cut) If you lower TP cut to 5 GeV, amost 10% of events have noise in full RBX Pixel/HPD multiplicity: 50% of events have one or two pixels firing. Multi-pixel events (>2pixels/HPD) have flat distribution (as likely to have 4 pixels firing as 10 or 16. In HB, there are five most noisy single-HPD (>100 events/6k total) -1, -52, -63, -68, +8 Not all HPDs which are noisy in single-HPD mode, are also noisy in multi-HPD mode. HPD -63, -68 and +8 only contribute to single-HPD noise HPDs -1 and -52 contribute both to single-HPD noise and multi-HPD noise.

  18. Back-up slides

  19. HB TP occupancy, TP> 5 GeV(includes also fake triggers)40k events from r35672(trig.th=20GeV)

  20. HB TP occupancy, TP> 5 GeV(fake triggers removed)40k events from r35672 (trig.th=20GeV)

  21. HB TP occupancy, TP>10 GeV(fake triggers removed)40k events from r35605 (trig.th=10GeV)

  22. HB TP occupancy, TP > 20GeV(fake triggers removed)40k events from r35672(trig.th=20GeV)

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