1

Summary on the Wednesday access of BBC FEM

07/28/05Kazuhisa Yamaura

Koutaro Kijima

Daisuke Watanabe

Misaki Ouchida

2

Unstable channels on the slope (ADC/injected charge)

• Finally 12 daughter cards were replaced.

– Adc[6] → QVC, ADC

– Adc[77] → QVC, ADC

– Adc[78] → QVC, ADC, Internal charge injector with discriminator x 2

– Adc[126] → QVC, ADC, Internal charge injector with discriminator x2

Daily FEM calibration dataSlope vs. Date

〇 good channel● unstable channel

Slo

pe

Date

3

Checked items for the replaced channels

Confirmed these are all fine.– ADC pedestal (for offline analysis).– Linearity of ADC gain.

Confirmed these are not changed.– TDC overflow (used for BBLL1).– TDC timing offset (used for BBLL1).

4

Stability of the slope after the replacement

before after replacement

These are all stable after the replacement.

5

LUT for BBLL1

• Current LUT does not include 5mm of Z-vertex offset, which was obtained by the difference from Z-vertex of tracking.

• We would like to update the LUT by this reason.• We will make the LUT with new calibration

constants obtained after the replacement, although TDC overflow values and timing offsets are not changed so much.

• We will make it by this weekend.

6

Threshold scan

• There were some bad channels in Run5 and Run6 on the pedestal value obtained by the internal charge injection. Pedestal were shifted through the run.

• So we have made calibration constants (pedestal) by the threshold scan with collision data.

• In this run, we have confirmed there are no problematic channels, but we had to confirm it for the replaced channels by comparing with the threshold scan data.

• We confirmed quickly the pedestal for the replaced channels are good by the scanned data of last Thursday.

• However the statistics is not enough to obtain the accurate value of the pedestal by the data.

• To obtain the accurate pedestal, 500k BBLL1 triggered event×5 sets of threshold are needed. It takes about 30 min.×5 typically at the end of store (~0.3 kHz).

Pedestal shift in Run5Pedestal at the beginning of Run5Pedestal at the end of Run5

Run5