ECAL: HV tuning

Irina Machikhiliyan, 21.03.2012

• Input parameters:– π⁰ calibration latest (corresponds to the run #102323, 25 Sept

2011, provided by MN)– Outer border cells: PmPin ratios– Cells with changed Pm/C-W are excluded

• New HV test (5 TAE, 11 KHz ON):– run #108978 (10K) – old HV– run #108982 (10K) – new HV + LED intensity tuned

• MV consumption change (per side): 1.116A → 1.126A(No beam, no LED flashing)

ECAL HV adjustment test

Irina Machikhiliyan, 21.03.2012

K1 = required gain change

K1 / K2

I 25/41 ( k1 = 1.35)

K1 / K2

K1 – required gain change ( input parameter)K2 = PmToPin(new HV) / pmToPin(old HV) - measured gain change after HV adjustment

HV(new) / HV (old)

LED system time alignment (#108982)

Irina Machikhiliyan, 21.03.2012

P1 / (P1+T0+N1) P1 / (P1+T0+N1), averaged over LED

N1 / (P1+T0+N1), averaged over LEDN1 / (P1+T0+N1)

Timing is acceptable, but it would be better to make a tuning (after detector timing is checked with TAE events)

Further steps

Irina Machikhiliyan, 21.03.2012

• FEB fine delays check/tuning to account for new HV (m.p. done by Frederic)

• Calibration constants reset (m.p. done by Olivier)• Detector timing check with TAE• Final tuning of LED/PIN timing

Extra

Irina Machikhiliyan, 21.03.2012

PmPin change during the shutdown (1)

Irina Machikhiliyan, 21.03.2012

Reference runs: #104406 (beginning of the fill 2267, 30 Oct 2011)# 108978 (12 Mar 2012)

PmPin(12 Mar)/PmPin(30 Oct)

PmPin change during the shutdown (2)

Irina Machikhiliyan, 21.03.2012

PmPin(12 Mar)/PmPin(30 Oct), Inner

PmPin(12 Mar)/PmPin(30 Oct), Middle

PmPin(12 Mar)/PmPin(30 Oct), Outer

Average recovery is on the level of 8÷13%, strongly depends on the detector area (up to 25% in the “horns”)