On behalf of joint ITEP / IHEP team: A. Arefiev, N. Filimonov, T. Kvaratskheliya, I. Machikhiliyan, P. Shatalov, T. Zakoryuchkina, A. Zhokhov, S. Zvyagintsev

On behalf of joint ITEP / IHEP team:

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

ECAL: status and plans

Irina Machikhiliyan, 23.02.2009

Outline: A-side C-side Lab activities Further plans

ECAL A-side


C-W modification is almost finished:

Outer / Middle region are done; Few boxes are still missing in the

Inner section;

Is it possible to start the installation this week in order to start the commissioning in the end of the next week / beginning of the week after the next?

Last week: installation and check of the HV-boxes system:

Successfully passed test procedure For a moment is disconnected from

power supplies (safety for the future installation of PM/C-W)Green: ready for installation;

White: to be done;

Commissioning of the ECAL C-side


Took place in the week of 2 – 8 Feb

Reference data samples:

#43821 PM HV nominal, LED LV = (nominal + 1V), 1K of 5 TAE events, LED trigger rate 56 Hz (taken 08.02.09)

#43822 PM HV nominal, LED LV nominal, 1K of 5 TAE events, LED trigger rate 56 Hz (taken 08.02.09)

#43815 PM HV nominal, LED LV nominal, ~52.5K of events, LED trigger rate 3 Hz, 5 TAE events (almost 5 hours stability run, taken 07.02.09)


Test program:- Check of the functionality of PMs / LEDs: several cables were not plugged, fixed; 5

doublets PM/C-W showed small C-W noise tails, replaced; - Connectivity test (swapped cables): some swapped control cabling in the Inner

section, fixed;- Pulser test to check connectors quality (thanks to Jacques): 3 connectors on signal

cables on PM side, replaced;- Adjustment of integrators;- Update of connectivity in Database; - ~5 hours stability measurements;

Remaining problems / tasks: Cells O 15/37(09/11/31) and M 01/29 (11/08/09) – problem on FEB side according to

pulser test (Jacques knows); Couple of cells showed instability: to be watched further to understand the reason; One LED (C1.16.1) is unstable (problems is known since the last year, LED driver

will be replaced);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 C-side


r.m.s. of pedestal distribution

Relative signal deviation, 4.8

hours

Relative signal deviation, ~4

hours

Response on LED, nominal settings;

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


Equipment used: High voltage probe TENMA - 72-3040 + FLUKE 45

MULTIMETER Both checked with NIM Power Supplies - N470 in the range of

output voltages 0÷1.3kV: accuracy of the measurement is on the level of 0.1%

Measurement conditions: 14 C-W bases of HCAL_mc design 10 C-W bases of ECAL_mc design PM control voltage is in the range 0÷3.8 V Medium voltage setting +96V

Lab measurements: final dependence of output C-W HV on the control voltage


Lab measurements: comparison of designs

HCAL_mc ECAL_mc

No difference between HCAL_mc and ECAL_mc was observed except for

the first point


Lab measurements: final dependence of output C-W HV on the control voltage

HCAL_mc+ ECAL_mc

The final formula is:

HV(V) = 6.3 + 421.4*Vctrl (V)

For Vctrl ~ 3.5V medium voltage setting must be +90V

+80V is not enough for “cosmics”


Lab measurements: reproducibility of output HV over different C-W

In the ECAL operating range (~1÷2V of Vctrl):

< 0.5% in HV or

<3.2% in gain

Contribution from HV-box (r.m.s. of Vctrl): < 0.36% in

Vctrl or < 2.3% in gain

In the ECAL operating range:

< 1.6% in HV or

<10.2% in gain

These numbers define the precision of the calibration which can be achieved by “hardware” methods

HV

HV

G

G

α (HAMAMATSU)

r.m.s., Volts Max spread, Volts

Further plans


This / next week: installation of PM/C-W on A-side;

Until mid. of March: A-side PM/C-W commissioning;

Starting from second half of March:

(a) In the lab: modification of spare C-W + repair;

(b) On ECAL detector: calibration of PM gain by photo-statistics; adjustment of LED intensities; etc;

Documents

On behalf of joint ITEP / IHEP team: A. Arefiev, N. Filimonov, T. Kvaratskheliya, I. Machikhiliyan, P. Shatalov, T. Zakoryuchkina, A. Zhokhov, S. Zvyagintsev