Commissioning of the ECAL A-side

Irina Machikhiliyan, 12.03.2009

Reference data samples:

#45498 PM HV nominal, LED LV = nominal, 5K of 5 TAE events, LED trigger rate 56 Hz, C-side is also included (taken 12.03.09)

#45396 PM HV nominal, LED LV nominal, ~34K of events, LED trigger rate 2 Hz, 5 TAE events, A-side only (almost 5 hours stability run, taken 10.03.09)

On behalf of joint ITEP / IHEP team:

A. Arefiev, N. Filimonov, T. Kvaratskheliya, I. Machikhiliyan , P. Shatalov, T. Zakoryuchkina, A. Zhokhov, S. Zvyagintsev

Irina Machikhiliyan, 12.03.2009

Test program:- Check of the functionality of PMs / LEDs: several cables were not plugged, fixed; few PM/LED

power distribution cables are repaired; - Connectivity test (swapped cables): some swapped control / signal cabling in the Inner section,

both PM and FEB sides, fixed;- Pulser test to check connectors quality: 9 connectors on signal cables on PM side, repaired or

replaced;- Update / check of connectivity in Database; - ~5 hours stability measurements; - Adjustment of integrators: were adjusted 11 of March, but 12 March it was found that pedestal

values for two of them drifted. The experience from both C and A-sides shows that current system is not very stable and its adjustment is painful and time-consuming. The general feeling of the group is that it will be worth to modify the circuitry to achieve better performance. Pavel kindly agreed to take care of it. For a moment we have a prototype ready – to be checked on detector.

Remaining problems / tasks: Cells O 58/28(21/08/18) and O 35/46 (19/12/03) – problem on FEB side; Couple of cells showed instability: to be watched further to understand the reason; One RJ-45 cable with connector of poor quality (fire signal distribution for LED A310.4), to be

repaired (not urgent, LED is now operational)For a moment: LED intensities are not optimally adjusted. It does not make sense to do it now: they will

be tuned after the calibration of PM gains will be done; PIN system functionality is not yet checked. To be done (data are collected, to be

analyzed);

Commissioning of the ECAL A-side

Irina Machikhiliyan, 12.03.2009

r.m.s. of pedestal distribution

r.m.s. of pedestal distribution

“Wide” pedestals:

Most of the cells (12) belong to FEB 15 (crate 19)

“Narrow” pedestals:

all from FEB 13 (crate 15)

ECAL A-side, performance-I(pedestal rms)

Irina Machikhiliyan, 12.03.2009

ECAL A-side, performance-II(LEDs)

Response on LED, nominal settings(1d)

(!) 13 cells: amplitude is below 150 counts (!)

(among them ~ 6 cells with damaged optical fibers)

Response on LED, nominal settings (2d)

All three optical bundles, which were replaced – work well!

Irina Machikhiliyan, 12.03.2009

ECAL A-side, performance-III(stability)

Relative signal deviation, first hour excluded (stabilization)

99% of cells are stable

within 1%

Relative signal deviation, all 4.7 hours of data taking

83% of cells are stable within 1%

95% of cells are stable within 2%

several cells with small / absent signal are excluded,

few of them were finally repaired

Irina Machikhiliyan, 12.03.2009

ECAL C-side:? time-alignment problem ?

It seems that some C-side LEDs are even beyond the

TAE sequence and therefore they are missing

Upd: 23 March: According to Anatoly, there was a problem with LEDTSB recipes after

power cut. Should be solved by now.

LED response, Prev2 LED response, Prev1 LED response, T0

LED response, Next1 LED response, Next2