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Exposure Log


Start Time

End Time

Rate (rad/s)

Total Dose

Integrated Dose







Testing Log


Start Time

End Time

Start Run






noticed lots of bonds had been damaged on CoB
runStart -t MpsMaskThresholdScan -v 21 -n 42





Replaced CoB to freezer





Removed Sensor from freezer
held at ground annealing





removed grounding and inserted CoB onto PCB
runStart -t MpsMaskThresholdScan -v 21 -n 42

09:00 02/03/11

Sensor placed in xray tube at an increased rate of 97.9 rad/s due to tech being ill and needing to go home. Total dose of 1MRad achieved within 2 hours and 50 minutes and then the sensor was returned to freezer

12:10 02/03/11

Removed sensor from freezer and allowed sensor to defrost (until all condensation had evaporated) and noticed that there were lots of broken bonds on one side of the sensor.

SensorLoadv1.1 returned no bad pixels (confusing) so decided to test it and see what happens anyway. Ran 42 runs to scan rows 66-107

13.52 02/03/11

42 scans have completed and returned the CoB to the freezer

14:30 02/03/11

Analysed the scans to see if any of the data is actually useable (file sizes ~3.5 MB instead of 4.8 MB) the following are the comparisons for the pixels which "worked" in the damaged sensor for the number of hits per pixel, the mean hits per pixel and the sigma per pixel (returned from mpsAnalysis). There is no guarentee at this point that the pixels have actually been read out correctly

Can see a large reduced number of hits over the whole sensor. Can see that the mean of the distributions seems to have not moved but the width is now much wider (plots need fitting). Surprisingly, over the whole sensor the Sigma values returned from mpsAnalysis only vary very slightly

15:00 02/03/11

When looking at the changes on a pixel by pixel basis by looking at the value for no exposure - value for 1MRad exposure

We can see that the hits has a strange double peak feature, one around 0 difference and the other around 1500. The mean has a large peak at zero difference but a huge width of +/- 50 and the sigma (RMS) plots show a difference of basically zero.

When looking at the pixel maps it becomes clear that all of the sensors with very little change in the values seem to lie within the same region of the sensor to the far right. As the increased rate leads to a smaller less uniform beam spot it if feasible that this region of the sensor did not recieve the same dose as the rest. The Hit maps also show the regions of the sensor which were read out due to the broken bonds

15:20 02/03/11

Decided that as we could read out ~3.5k pixels it was worth continuing the annealing studies so removed the sensor from the freezer and attached to ground

13:58 03/03/11

Started the 24 hour annealing scan. 24 hours since the start of the previous scan - the time in the freezer yesterday afternoon

first run of scan = 912154

15:32 03/03/11

Scans finished so sensor returned to ground. Quick check of results shows quite a large increase in the number of hits mean ~3300 at 0 hours ~3700 at 24 hours

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