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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:

run 902 att=0.005

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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                              Image Added <-Tilted 2x1-> Image Removed

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:

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