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The BLM calibration is performed with a 137Cs source. The source emits a single gamma at 661.7 keV. The source activity was 323.2 kBq as of 11.01.2019. Its serial number is AB-9020, 370 kBq when purchased.
I have used 10 s integration time and set all BLM to count 30 k. (3 kHz)
Note on the light yield. Reference Glenn Knoll 3rd edition p.235 and p226 NE102A 10 k photons per MeV. BC400 light output 0.65 of NE102A (anthrscene). Hence one can expect: 6500 photons / keV
Bellow is a spectrum taken with the HDO6104A scope when for a BLM set to count 3 kHz (in this case XP2972
CBS - Cathode Blue sensitivity ABS - For a anode blue sensitivity Id - Dark current
SN | CBS [uA/lmF] | ABS [A/lmF] | HV [V] | Id[nA] | Gain [106] | Comment |
---|---|---|---|---|---|---|
34391 | 12.6 | 10 | 1188 | 4.98 | 0.79 | new, will be installed in TE1 |
29181 | used, low gain, was in S07DL1R |
Reason for the service: The detector counts more than 10 times compare to the detectors above, left and right of it. Will examine it if:
HV [V] | Ileakage [uA] | Counts[Hz] |
---|---|---|
300 | 200 | 0 |
1000 | 672 | 0 |
1500 | 1008 | 30 |
The Standard operating voltage is 1100 V, Il = 739 uA, counting rate bellow 5 Hz