Initial tests without sensor attached:

  

The noise is around 16 ADC units across all the channels. The channels receiving pulses have narrow distributions.

 

Baseline after bonding ALL channels:

Baseline after removing GND1 to GND2 APV frontend short (50 V on left 0 V on right):

Using the 0 V noise data, here is a list of channels below 30 ADC counts of ENC:

 

           Sector B                        Sector A
i      i%128    128+(i%128)    2*128-(i%128)-1    128-(i%128)-1
APV1
131    3        131            252                124
159    31       159            224                96
162    34       162            221                93
179    51       179            204                76
211    83       211            172                44
255    127      255            128                0
APV2
262    6        134            249                121
263    7        135            248                120
274    18       146            237                109
284    28       156            227                99
304    48       176            207                79
307    51       179            204                76
341    85       213            170                42
369    113      241            142                14
373    117      245            138                10
APV3
384    0        128            255                127
482    98       226            157                29
497    113      241            142                14
APV4
617    105      233            150                22
634    122      250            133                5

The pinholes reported for this sensor by the fab are:

Sector A: [44, 76, 93, 96, 124, 138, 142, 170, 204, 207, 227, 249]

Sector B: [98]

This is 13 total pinholes reported, whereas we see 20 low noise channels.

If we assume this APV mapping:

APV1 on the beam side of Sector A
APV2 on the far side of Sector A
APV3 on the beam side of Sector B
APV4 on the far side of Sector B

Then all 13 reported pinholes are low noise channels.

Calibration Runs with 50 V Biased Sensor:

Looking at sample 3 since this is closest to the peak of the pulse.

This is calgroup 3                                                                                                    Channel 482 ADC distribution (expected shape)

         

Channel 355:                                                                                            Channel 307:

                          

 

All channels in APV2 have the extra peak below the main peak.

The channel seen in APV1 above is a reported pinhole (channel 211):

Not all reported pinholes look strange like this (channel 179):

 

  • No labels