QUAD MODULE TESTING 18 th January 2013 Kate Doonan University of Glasgow

Quad Module: 200μm ROC Chip ID 1 – no longer working due to accidental damage. Bonds will be checked Chip ID 3 – not working: no RX signal. Bonds will be checked. Chip ID 4 – not wire-bonded yet Chip ID 2 – Working: Tuned to 3200e and 1600e thresholds Working Chip 1

Chip ID 2 Characterisation Biased to -100V at room temperature Module kept from heating by constant airflow from fan from the side Kept from light exposure using dark box Leakage current 50nA in complete darkness 2

Chip ID 2: Tune to 3200e threshold Threshold tuned to 3200e Best result obtained through standard TDAC- FDAC-TDAC cycle during tuning 3

Initial TDAC tune gave better result but ToT had to be tuned Taken sample of pixels here to make scan shorter Chip ID 2: Tune to 3200e threshold 4

Low Noise: 116.4e. Sigma of 200e is considered acceptable Chip ID 2: Tune to 3200e threshold 5

Log Y used to look in detail at noise Chip ID 2: Tune to 3200e threshold 6

See chip is tuned to ToT ref. charge of 20ke Again, best result obtained through TDAC-FDAC-TDAC cycle Chip ID 2: Tune to 3200e 7

Initial FDAC tune gave good ToT but altered threshold value considerably Chip ID 2: Tune to 3200e 8

Noise 3200e: 10 mill events Bias OFF 9 Mask produced for pixels with occupancy over 1,000

Bias -100V Noise 3200e: 10 mill events 10 Mask produced for pixels with occupancy over 1,000

Bias OFF Some pixels exhibit crosstalk when sensor is unbiased 3200e Threshold 11

Bias -100V Fewer pixels exhibiting crosstalk at -100V e Threshold

A number of pixels are shown to be disconnected around the edges Will use ROOT macro to ascertain exact number of pixels that are disconnected 3200e Threshold Scan 0V – bump yield 13

Zoom into 120e region Judging by eye, ~6,500 pixels exhibit noise around 120e giving a yield of ~25% disconnected pixels 3200e Threshold Scan 0V – bump yield 14

Behaviour of Single Chip Noise plots of single chip (VTT Assembly 15) at threshold of 3200e: 0V 100V 15

Threshold tuned to 1600e Some pixels remain tuned to threshold of 3200e Tuning down was very quickly done Chip ID 2: Tune to 1600e threshold 16

Again, low noise: 133e Sigma <200e Chip ID 2: Tune to 1600e threshold 17

Log Y used to look in detail at noise Chip ID 2: Tune to 1600e threshold 18

ToT not perfect but in correct region. Could be improved with more fine-tuning. Chip ID 2: Tune to 1600e 19

Bias OFF Noise 1600e 20 Mask produced for pixels with occupancy over 1,000

Bias -100V Noise 1600e 21 Mask produced for pixels with occupancy over 1,000

Chip exhibits more crosstalk at this lower threshold 1600e Threshold 22

No discernible peak around 120e Compare to biased assembly in next slide 1600e Threshold Scan 0V – bump yield 23

1600e Threshold Scan 0V – bump yield 24

Log Y used to look in detail at noise Pixels with highest noise values are on top in occupancy plot 1600e Threshold Scan 0V – bump yield 25

Zoom into top rows of occupancy plot Noise in these pixels is >500e 1600e Threshold Scan 0V – bump yield 26

Looking at SCURVES for a sample of pixels HOT PIXEL 1600e Threshold Scan 0V SCURVES Row 4, Column 14: 27

Looking at SCURVES for a sample of pixels WELL-BEHAVED PIXEL 1600e Threshold Scan 0V SCURVES Row 261, Column 31: 28

Looking at SCURVES for a sample of pixels SWITCHED-OFF/BROKEN PIXEL 1600e Threshold Scan 0V SCURVES Row 144, Column 13: 29

Summary Chip 2 can be tuned to threshold of 3200e and 1600e and a ToT of 8 ~25% disconnected pixels In general, this assembly behaves as a single chip assembly Nothing to indicate otherwise 30

Work yet to do … Fine-tuning of Chip 2 to threshold of 1600e/ToT=8 Use ROOT macro to find number of disconnected bumps on Chip 2 Set-up Sr90 scans – beta particles should penetrate to other side to be detected in PMT for triggering Try Am241 scans – HITOR not bonded and it is thought that this is needed for Am241 scans Wire-bonding of Chip 4 Tuning and characterisation of Chip 4 31