No dead cells (yet) The integrated luminosity since the last meeting: 477 pb -1 ; since the last TS:...
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Transcript of No dead cells (yet) The integrated luminosity since the last meeting: 477 pb -1 ; since the last TS:...
Yu. Guz
• No dead cells (yet)
• The integrated luminosity
• since the last meeting: 477 pb-1;
• since the last TS: 609 pb-1;
• smooth operation since the last meeting, with several LED based gain corrections: 16-Oct, 21-Oct, 01-Nov, 09-Nov, 18-Nov .
HCAL status
12012-11-21
Yu. Guz
HCAL HV corrections – LED viewLED-based HV correctionssum/sumref, 56 central cells
60 pb-1
TS3,
sou
rce
calib
ratio
n 87 pb-1 129 pb-1
Since the last TS, 6 LED-based corrections: 04-Oct, 16-Oct, 21-Oct, 01-Nov, 09-Nov, 18-Nov
22012-11-21
101 pb-1
TS3 reference: 2012-09-30 10:05:56
107 pb-1
before TS3, a “plastic ageing” correction was used, which appeared to be somewhat overcompensating. Now the correction map was updated on the basis of the 137Cs scans at TS2 and TS3.
103 pb-1
Yu. Guz
HCAL HV corrections in 2012
32012-11-21
• total of 4 137Cs calibrations and 16 LED-based corrections performed. • 2-3 more LED based corrections before the end of 2012• a 137Cs scan will be performed at the end of the 2012 run
attempts of compensation for the “plastic ageing” are visible.
LED-based HV correctionssum/sumref, 56 central cells
shut
dow
n 13
7 Cs
calib
ratio
n
TS1,
137 C
s ca
libra
tion
TS2,
137 C
s ca
libra
tion
TS3,
137 C
s ca
libra
tion
Yu. Guz
HCAL HV corrections in 2012 - II
42012-11-21
LED-based HV correctionssum/sumref, 56 central cells
TS1 TS2 TS3
an alternative view, as a function of delivered luminosity
Yu. Guz 52012-11-21
HCAL HV corrections in 2012 – L0Hadron view
ECAL updateTS1 TS2 TS3
TCK changes
? ~ 07-Nov
Yu. Guz 62012-11-21
HCAL LED / PIN stability
A systematic drift of PIN amplitudes is visible in HCAL: on average, -1.4% since April, -0.4% since TS3. As it is not clear whether it is because of reduction of the LED light or ageing of PINs themselves, the corresponding correction is not applied to PMTs (anyway, the effect is small between two TSs).
Such effect is not observed in ECAL, probably because the ECAL LEDs and PINs are installed out of the detector aperture.
Yu. Guz 72012-11-21
HCAL LED / PIN stability
The PINs are not taken into account, because:
• the effect between two TS (source calibrations) is small (~0.3-0.4%)
• it is not clear whether it is because of reduction of the LED light or ageing of PINs themselves. The comparison of the Outer PMT trends with and without PIN corrections gives some preference to the hypothesis that the reduction is due to PINs themselves and not LED light (next slide).
• there are several PINs which have instabilities at this level due to contacts at the FEB inputs (next-to-next slide)
Yu. Guz 82012-11-21
HCAL LED / PIN stability
In case of not correcting to PINs, the trend looks more stable. This supports the hypothesis that this is the degradation of PIN response and not LED light.
There is an overall shift by -0.65% in the period after the TS3. It is due to the source calibration, this was mentioned in the previous HCAL report, 10-Oct, slide 8.
NOT corrected for PINs
corrected for PINs
Yu. Guz 92012-11-21
HCAL LED / PIN stability
PINs with irregular fluctuations, presumably due to problems in FEB input contacts