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ECAL

Irina Machikhiliyan , 20.07.2011. Technical stop: Recovery during July technical stop (detector + monitoring system) C-W pumping frequency measurements Comparison of LEDs with minbias data ECAL cells DQ. ECAL. Irina Machikhiliyan , 20.07.2011. Fills 1799 – 1955.

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ECAL

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  1. Irina Machikhiliyan, 20.07.2011 • Technical stop: • Recovery during July technical stop (detector + monitoring system) • C-W pumping frequency measurements • Comparison of LEDs with minbias data • ECAL cells DQ ECAL

  2. Irina Machikhiliyan, 20.07.2011 Fills 1799 – 1955 Average relative PmToPin change with respect to 1st run (fill 1799) Time, minutes. One point per run 1955, 18/7/11 1944, 14/7/11 1901, 28/6/11 1799, 21/5/11 Red: physics runs Black: the rest

  3. Irina Machikhiliyan, 20.07.2011 Fills 1799 – 1955, Inner Average relative PmToPin change with respect to 1st run (fill 1799) Time, minutes. One point per run 1955, 18/7/11 1944, 14/7/11 1901, 28/6/11 1799, 21/5/11

  4. Irina Machikhiliyan, 20.07.2011 Fills 1799 – 1955, Middle Average relative PmToPin change with respect to 1st run (fill 1799) Time, minutes. One point per run 1955, 18/7/11 1944, 14/7/11 1901, 28/6/11 1799, 21/5/11

  5. Irina Machikhiliyan, 20.07.2011 Fills 1799 – 1955, Outer Average relative PmToPin change with respect to 1st run (fill 1799) Time, minutes. One point per run 1955, 18/7/11 1944, 14/7/11 1901, 28/6/11 1799, 21/5/11

  6. Run #95947 (fill 1944) wrt run #94385 (last physics run of the latest fill 1901) Irina Machikhiliyan, 20.07.2011 PmToPin(95947) /PmToPin(94385) PmToPin(94860) /PmToPin(94385) R/O crate 20, Not present in #94860 (6 Jul), present in # 95656 (12 Jul) PmToPin(94860) /PmToPin(94385) = 1.023 PmToPin(95656) /PmToPin(94385) = 1.009 Up to 12% recovery in the Innermost / “horn” areas. Average ratio per section: Inner: 1.045 (r.m.s. 0.019) Middle: 1.029 (r.m.s. 0.019) Outer: 1.018 (r.m.s. 0.022)

  7. Irina Machikhiliyan, 20.07.2011 C-W pumping frequency (done together with Yu. Guz) - initial measurement: 10 May, logbook entry:http://lblogbook.cern.ch/CALO/1587 - second measurement: 05 Jul, logbook entry: http://lblogbook.cern.ch/CALO/1701 Average frequency <f>, kHz: Group # 10 May 5 Jul #1 64.8 61.9 #2 65.5 65.2 #3 68.9 69.1 #4 69.0 69.2 Innermost C-Ws (group #1) show decrease of <f> on ~4%, which must not affect C-W performance. <f>-values for other C-W groups are stable. 3 2 1 4

  8. Irina Machikhiliyan, 20.07.2011 LEDs vsmbias: fills 1799 – 1883 Average relative PmToPin change with respect to 1st run (fill 1799) Fill 1799: 21 May, 10.5 hours Fill 1883: 21 Jun, 18 hours Physics data: mbias selection Signal: position of π⁰ peak Photons: et > 300 MeV Run 94012 Run 92035

  9. Irina Machikhiliyan, 20.07.2011 LEDs vsmbias: fill1883, signal change during the fill (1) (PmPin(N) – PmPin(0)) / PmPin(0) (PmPin(N) – PmPin(0)) / PmPin(0) All cells Inner cells (M(N) – M(0)) / M(0) N (Relative run #) (M(N) – M(0)) / M(0) N (Relative run #) π⁰ peak, Inner Net π⁰ peak

  10. LEDs vsmbias: fill1883, signal change during the fill (2) Irina Machikhiliyan, 20.07.2011 (PmPin(N) – PmPin(0)) / PmPin(0) (PmPin(N) – PmPin(0)) / PmPin(0) For π⁰-signal: try to add other selections? (π⁰ position compatibility for different selections should be checked) Outer cells Middle cells (M(N) – M(0)) / M(0) N (Relative run #) (M(N) – M(0)) / M(0) N (Relative run #) π⁰ peak, Outer π⁰ peak, Middle

  11. Irina Machikhiliyan, 20.07.2011 Detection of problematic cells, fills 1799-1901 Correction factor for the last run of fill 1901 • (1) for each [physics] run #N and for each LED ratio R(N,LED) = <PMtoPIN(N, LED) / PMtoPIN(0, LED)> is produced. 1/ R(N,LED) serves as correction factor to crudely account for : • clear fibers rad. damage • signal change due to PM training • ? some other factors ? • (2) After correction is done, cell is markedas suspicious if: • - maximal deviation of corrected PMtoPIN(N) from the PMtoPIN(0) over all runs is ≥10% • - or signal change over two adjacentruns ≥ 5% • - ormaximal width of LED peak over all runs > threshold • (3) Individual check of suspicious cells (see next slide) • Finally : 19 cells have been found Average relative PmToPin change with respect to 1strun, corrected Time, minutes

  12. Irina Machikhiliyan, 20.07.2011 Example of the cell with “unexpected” behaviour (O 61/28) Original trend 3.5% Corrected trend 6% Correction makes things worse Cells where correction makes things worse Correction factor for current cell

  13. Irina Machikhiliyan, 20.07.2011 List of problems + suggestions • One cell out of 19 must be excluded for all runs (O 51/56, bad C-W: unstable, noisy spectrum, presently: very low gain) • The rest: noticeable signal change in one-few-many runs. In many cases it is accompanied by anincrease of the r.m.sof LED peak due to noisy spectrum. Signal change: could be gradual drift during some time period(2 cells); one abrupt change(1 cell); unstable behaviour (more than one abrupt change, 11 cells) • Suggestion: • if for certain runs spectra are noisy but signal change is small (1-2%), do nothing (4 cells) • if few runs are affected and signal change is large, mask the cell for that particular run(s) or make [rough] gain corrections if possible • if during certain period signal variations are large and frequent: exclude such cell for this period Correction factors / periods to mask for each cells could be provided before the beginning of the next week. Do we agree that the reference point should be fill 1799? Run-based or fill based corrections?

  14. Irina Machikhiliyan, 20.07.2011 Example #1: Cell O-01-32 Average relative PmToPin change with respect to 1strun LED peak r.m.s. (ADC counts) The signal change is not significant, no action is needed

  15. Example #2: Cell O-46-44 Irina Machikhiliyan, 20.07.2011 Average relative PmToPin change with respect to 1strun In one run over several hundred signal decreased, r.m.s. OK Mask this cell for one run? LED peak r.m.s. (ADC counts)

  16. Example #3: Cell O-02-26 Irina Machikhiliyan, 20.07.2011 Average relative PmToPin change with respect to 1strun 1400 ADC cnt Make correction for this period Transition LED peak r.m.s. (ADC counts) 1300 ADC cnt

  17. Example #4: Cell O-09-15 Irina Machikhiliyan, 20.07.2011 Average relative PmToPin change with respect to 1strun 1100 ADC cnt Make correction for this period + exclude some runs Transition LED peak r.m.s. (ADC counts) 800 ADC cnt

  18. Ex #6:Cell O-09-17 Ex #5:Cell I-40-29 Average relative PmToPin change with respect to 1strun Average relative PmToPin change with respect to 1strun LED peak r.m.s. (ADC counts) LED peak r.m.s. (ADC counts) Large signal variation, exclude period t<22000, correct the rest w.r.t. first point Large signal variation, exclude period 20000 - 30000

  19. Ex #8:Cell I-41-43 Ex #7: Cell O-08-57 Average relative PmToPin change with respect to 1strun Average relative PmToPin change with respect to 1strun LED peak r.m.s. (ADC counts) LED peak r.m.s. (ADC counts) Gradual signal increase for t < 5000. Correct all points > 5000 ? Signal increase, than gradual decrease for t < 5000. Correct points < 5000 ?

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