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

2. 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. 3 TP vs ADC, r35672 Fake triggers ~ 90% of events Good triggers ~ 10% of events

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

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

6. 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. 7 TP vs digi mismatch existed also in GREN HCAL Trigger Run 30205: HCAL trigger only Run 30478: DT+RPC+HCAL trigger GREN run, HCAL top-and-bottom trigger

8. 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. 9 TP and QIE energy, r35605 (Trig Th = 10 GeV) Lin ADC counts TP 100 GeV = 500 Lin Qie counts

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

11. 11 Single HPD noise: Event examples

12. 12 Single HPD noise

13. 13 Multi-HPD noise: Event examples

14. 14 Multi-HPD noise

15. 15 HPD and pixel multiplicity

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

17. 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. 18 Back-up slides

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

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

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

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