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HCAL status

HCAL status. HCAL 137 Cs calibration 30 /08/2011.

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HCAL status

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  1. HCAL status Yu.Guz

  2. HCAL 137Cs calibration 30/08/2011 Since the previous calibration (01-Aug-2011), 30days passed, delivered integrated luminosity was 222pb-1. The nominal calibration was last time restored 01-Aug by modifying the HV according to the result of the 137Cs calibration of 01-Aug. Results: the deviation from nominal of -25%...+22% is seen in 137Cs current. A systematical response reduction in the central region, as expected; the magnitude in the cells near the beam pipe is higher then last time, with 111 pb-1 (reminder at the next slide). The HV change necessary for the correction is also shown. The HV recipes were updated on 01-Sep. The previous recipe is kept as PHYS_AUG2011. Yu. Guz

  3. HCAL 137Cs calibration 01/08/2011 Was undertaken out of technical stop, in order to better compensate for HCAL PMT ageing. Since the previous calibration (05-Jul-2011), 27 days passed, delivered integrated luminosity was 111 pb-1. The nominal calibration was last time restored 07-Jul by modifying the HV according to the result of the 137Cs calibration of 05-Jul. The resulting hadron trigger rate change was ~30% – too much. Results: the deviation from nominal of -25%...+9% is seen in 137Cs current. A systematical response reduction in the central region, as expected. The HV change necessary for the correction is also shown. The correction is much less than last time, 05-Jul-2011 (reminder at the next slide). The HV recipes were updated on 01-Aug. The previous recipe is kept as PHYS_JUL2011. Another source calibration was done yesterday, 30-Aug; the data processing is in progress. Yu. Guz

  4. Period of 07 — 20 September 2011 (110/pb), long term instabilities up to ~5-10% in the most busy cells around the beam pipe. Somewhat more, in spite of less lumi (110/pb vs 222/pb). Yu.Guz

  5. Period of 01 — 22 August 2011 (222/pb), long term instabilities up to ~5-10% in the most busy cells around the beam pipe. Yu.Guz

  6. Radiation damage of tiles and fibers 30-Aug vs 29-Mar (758pb-1) Further decrease in the centre Yu. Guz

  7. Radiation damage of tiles and fibers 01-Aug vs 29-Mar (536 pb-1) Yu. Guz

  8. Period of 14-Jul – 20 Sep 2011 It looks like that the PMT short term instability is increasing with time (or with integrated current); in fact this was also observed in the lab in 2010. Yu.Guz

  9. The whole story, 13-Mar – 23 Aug 2011 Recipe update failure, 13-May Reason of (a half of) the “hadron trigger rate problem” appeared in July was the recipe failure happened 13-May: the HV correction was in fact not done, the system used old values (this is not impossible, similar problem occurred in HCAL LEDTSB side C, see CALO logbook entries 1714, 1715). LED data has to be carefully monitored in future. Yu.Guz

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