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Average amplitude and RMS over pads for
...
runs
...
in the range 898-914
Average amplitude and their RMS is calculated over all "good" pixels for each ASIC
in each event. The event by event variation of the average amplitude demonstrates the "common-noise"
background. The value of RMS shows a spread of amplitudes over ASIC. One would expect the event by event variation of RMS should be small.
In run 898 ASIC 4 and 8 RMS is step-wise changing from ~40 to ~90 ADC units. In ASICs 7 and 14 RMS is rising with event number...
Run 898 dark rate:
r0898-s00:
r0898-s01:
Run 902 att=0.005
Run 909 att=1 low gain
CSpad images for runs 898-914
Image for each run is obtained by averaging of 100 events (rate is normalized per a single event).
Bad pixel map
Use file provided by Philip Hart to remove all bad pixel-channels:
Exceptional pixel file for Cspad1 made from xppcom10/525 and xpp23210/449
- 1=very hot (>20 ADU in pedestal run) - 134 pixels, or 0.02%
- 2=hot (>10 ADU in pedestal run) - 5026 pixels, or 0.9%
- 4=dead (noise < 3 ADU in data run - almost all at 0 or 1 ADU) - 698 pixels, or 0.1%
All marked pixels are removed from further analysis
Run 898 dark rate for high gain mode; plor shows the dark rate difference between low and high gain r898-907
Run 899 att=0.1 (dark rate is subtracted using r898)
Run 900 att=0.02 (dark rate is subtracted using r898)
Run 901 att=0.002 (dark rate is subtracted using r898)
Run 902 att=0.005 (dark rate is subtracted using r898)
Run 903 att=0.005 low gain (dark rate is subtracted using r907)
Run 904 att=0.1 low gain (dark rate is subtracted using r907)
Run 905 att=0.5 low gain (dark rate is subtracted using r907)
Run 906 att=1 low gain (dark rate is subtracted using r907)
Run 907 dark image for low gain
run 908 dark image for low gain (dark rate is subtracted using r907) Difference between two dark rate images
Run 909 att=1 low gain (dark rate is subtracted using r907)
Run 910 att=1 low gain (dark rate is subtracted using r907)
Run 911 att=1 low gain (dark rate is subtracted using r907) Detector is moved for few mm
Run 912 att=0.1 low gain (dark rate is subtracted using r907)
Run 913 att=0.1 low gain with wires (dark rate is subtracted using r907)
Run 914 att=0.1 low gain with wires (dark rate is subtracted using r907)
We use configuration parameters from microscopic (optical) measurement. It is clear that this configuration parameters are not perfect for real detector; some of 2x1are significantly ~1mm moved w.r.t. microscopic (optical) measurement.
<- NON tilted 2x1 
<-Tilted 2x1
Manipulation with images
Difference between runs 904(before move) - 912(moved), both runs att = 0.1
The difference between the original and moved image is relatively small ~2.5% of signal, but everything is done in low gain mode, where we actually have ~30 photons / pixel.
In summary, the nonuniformity of the illumination is ~2.5%.
Quantitatively this difference is presented in the next Z-projection plot.
Z-projections of (differential) images
Run numbers are shown in histogram titles:
The difference between dark image amplitudes at High and Low gain mode is ~155 ADC units.
Comparison of runs 899 and 904 (att.=0.1) gives the gain ratio High/Low = 495/66 = 7.5
Comparison of runs 902 and 903 (att.=0.05) gives the gain ratio High/Low = 26/4.5 = 5.8. So, the gain is not a lilear function of intensity...
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