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

and the dark rate difference between low and high gain runs 898-907:

Run 899 transm=0.1 (dark rate is subtracted using r898)

Run 900 transm=0.02 (dark rate is subtracted using r898)

Run 901 transm=0.002 (dark rate is subtracted using r898)

Run 902 transm=0.005 (dark rate is subtracted using r898)

Run 903 transm=0.005 low gain (dark rate is subtracted using r907)

Run 904 transm=0.1 low gain (dark rate is subtracted using r907)

Run 905 transm=0.5  low gain (dark rate is subtracted using r907)

Run 906 transm=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 transm=1 low gain (dark rate is subtracted using r907)

Run 910 transm=1 low gain (dark rate is subtracted using r907)

Run 911 transm=1 low gain (dark rate is subtracted using r907) Detector is moved for few mm

Run 912 transm=0.1 low gain (dark rate is subtracted using r907)

Run 913 transm=0.1 low gain with wires (dark rate is subtracted using r907)

Run 914 transm=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 transm = 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:

Bad pixels are removed. Top-left plot has a peak at "0", which arose in the difference of two ~820x820 plots from regions between ASICs.
The difference between dark image amplitudes at High and Low gain mode is ~155 ADC units.
Comparison of runs 899 and 904 (transm.=0.1) gives the gain ratio High/Low = 495/66 = 7.5
Comparison of runs 902 and 903 (transm.=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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