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  proton-capture on 118Te, Page 23 of 29  Not logged in ELOG logo
ID Date Author Categorydown Subject Year
  48   Sun Mar 15 17:13:21 2020 Laszlo, JanCalibrationthe x-ray gate issue 
We found a strange behaviour of our ADC gates for the x-ray detectors.
The setting as shown in the foto below corresponds to a delay of 5 us and a gate length of 15 us.
This is the only setting that produces nice spectra, even though the signals and gate are not aligned.
The setting is extremely sensitive to the delay 4 us still works but 3 or 7 us give already reduced energy values and beyond these values the spectra disapears.

For now it was decided to operate with this not-understood settings because the result is pretty good...
However, further investigation to understand whats happening would be desirable.

Additional note:
This effect appeared after using the new ortec SpecAmps. Before this we used old Tennelec Amps which delivered horrible resolution, but the gates and signals could be matched as expected at this time.
  49   Sun Mar 15 17:14:08 2020 LaszloCalibrationrun036 - Xray90 calib Am241, distance 200! 
Detector: 90
Source: Am241 
Distance: 200mm
Start time: 17:15:12 15.03.2020
Stop time:  17:32:17 15.03.2020

file name: run036_xxxx.lmd
avrg. rate: 450Hz
dead-time:  5%
  50   Sun Mar 15 17:33:17 2020 LaszloCalibrationrun037 - Xray90 calib Am241 
Detector: 90
Source: Am241 
Distance: 167.5mm
Start time: 17:40:00 15.03.2020
Stop time:  17:49:57 15.03.2020

file name: run037_xxxx.lmd
avrg. rate: 620Hz
dead-time:  7%

--------------------

update at 05.05.2020: the cables were probably twisted between the 90 and the 145 angle detectors.
  51   Sun Mar 15 17:50:42 2020 LaszloCalibrationrun038 - Xray90 calib Ba133, high rate 
Detector: 90
Source: Ba133 - high rate
Distance: 167.5mm
Start time: 17:53:38 15.03.2020
Stop time: 18:05:41 15.03.2020

file name: run038_xxxx.lmd
avrg. rate: 2.6kHz
dead-time:  26%


--------------------

update at 05.05.2020: the cables were probably twisted between the 90 and the 145 angle detectors.
  52   Sun Mar 15 18:09:19 2020 LaszloCalibrationrun039 - Xray90 calib Ba133 
Detector: 90
Source: Ba133
Distance: 167.5mm
Start time: 18:10:02 15.03.2020
Stop time:  18:47:36 15.03.2020

file name: run039_xxxx.lmd
avrg. rate: 150Hz
dead-time:  2%
  53   Sun Mar 15 18:53:42 2020 LaszloCalibrationrun040 - Xray145 calib Am241 
Detector: 145
Source: Am241
Distance: 305mm
Start time: 18:53:16 15.03.2020
Stop time: 19:18:35 15.03.2020

file name: run040_xxxx.lmd
avrg. rate: 230Hz
dead-time:  3%


--------------------

update at 05.05.2020: the cables were probably twisted between the 90 and the 145 angle detectors.
  54   Sun Mar 15 19:22:58 2020 LaszloCalibrationrun041 - Xray145 calib Ba133 - high rate 
Detector: 145
Source: Ba133
Distance: 305mm
Start time: 19:22:34 15.03.2020
Stop time: 19:38:44 15.03.2020

file name: run041_xxxx.lmd
avrg. rate: 1kHz
dead-time:  11%


--------------------

update at 05.05.2020: the cables were probably twisted between the 90 and the 145 angle detectors.
  55   Sun Mar 15 19:46:34 2020 LaszloCalibrationrun042 - Xray35 calib Ba133 - high rate 
Detector: 35
Source: Ba133, strong source
Distance: 334mm
Start time: 19:46:54 15.03.2020
Stop time:  20:20:14 15.03.2020

file name: run042_xxxx.lmd
avrg. rate: 60Hz
dead-time:  1%
  56   Sun Mar 15 20:26:08 2020 LaszloCalibrationrun043 - Xray35 calib Am241 
Detector: 35
Source: Am241
Distance: 334mm
Start time: 20:25:48 15.03.2020
Stop time:  20:56:56 15.03.2020

file name: run043_xxxx.lmd
avrg. rate: 20Hz
dead-time:  ~0%


--------------------

update at 05.05.2020: the cables were probably twisted between the 90 and the 145 angle detectors.
  58   Sun Mar 15 21:01:23 2020 LaszloCalibrationrun044 - Xray35 calib Ba133 - a night long run  
Detector: 35
Source: Ba133
Distance: 334mm
Start time: 21:01:26 15.03.2020
Stop time:  7:11:07 16.03.2020

file name: run044_xxxx.lmd
avrg. rate: 60Hz
dead-time:  1-2%


--------------------

update at 05.04.2020: the cables were probably twisted between the 90 and the 145 angle detectors. However, the id of the detector doesnt change, since there were no simultanious measurements (one source used with one detector a detector at a time)
  59   Mon Mar 16 15:15:22 2020 JanCalibrationGamma- and X-ray intensities for efficiency calib 
Intensities for special gamma or x-ray lines needed for efficiency calibration can be found here:


ENSDF
https://www.nndc.bnl.gov/ensdf/#

NUDAT
https://www.nndc.bnl.gov/nudat2/

An old but still usefull data base:
http://nucleardata.nuclear.lu.se/toi/nucSearch.asp
  87   Fri Mar 20 19:37:43 2020 JanCalibrationXray energies - rough 1. calibration  
-- E calibration seems to have changed! ---

This calibration is based on the source data taken before the experiment:

Xray1: E [keV] = ch*0.01582-1.963
Xray2: E [keV] = ch*0.01799-1.803
Xray3: E [keV] = ch*0.01941-2.618
  253   Mon Mar 23 15:48:15 2020 LaszloCalibrationrun105 - Xray90 calib Am241, distance 167.5mm, wrong? 
Detector: 90
Source: Am241 
Distance: 167.5mm
Start time: 15:46:49 23.03.2020
Stop time:  

file name: run105_xxxx.lmd
avrg. rate: 610Hz
dead-time:  7.5%

suspiciously not Gaussian shaped peaks --> investigation with oscilloscope
  254   Mon Mar 23 16:17:58 2020 LaszloCalibrationrun106 - garbage! 
run106 was clicked by accident, please delete!
  255   Mon Mar 23 16:21:33 2020 LaszloCalibrationrun107 - Xray90 calib Am241, distance 167.5mm 
Detector: 90
Source: Am241 
Distance: 167.5mm
Start time: 15:46:49 23.03.2020
Stop time:  17:32 23.03.2020

file name: run107_xxxx.lmd
avrg. rate: 610Hz
dead-time:  7%

not Gaussian shaped peaks, after previous investigations with the scope, the scope is disconnected.

Just to mention, in order to improve deadtime the other two Xray dets are disconnected.
  256   Mon Mar 23 17:32:42 2020 LaszloCalibrationrun108 - Xray90 calib Ba133, distance 167.5mm - high rate - deadtime too high! 
Detector: 90
Source: Ba133 - strong source
Distance: 167.5mm
Start time: 17:32:11 23.03.2020
Stop time:  17:35:34

file name: run108_xxxx.lmd
avrg. rate: 2.7kHz
dead-time:  26%
  257   Mon Mar 23 17:40:33 2020 LaszloCalibrationrun109 - Xray90 calib Ba133, distance 167.5mm -low rate 
Detector: 90
Source: Ba133 - weak source
Distance: 167.5mm
Start time: 17:40:11 23.03.2020
Stop time:  

file name: run109_xxxx.lmd
avrg. rate: 170Hz
dead-time:  2%
  259   Mon Mar 23 18:17:27 2020 LaszloCalibrationrun110 - Xray90 calib Ba133, distance 167.5mm -low rate - LESS NOISE 
Detector: 90
Source: Ba133 - weak source
Distance: 167.5mm
Start time: 18:14:50 23.03.2020
Stop time:  

file name: run110_xxxx.lmd
avrg. rate: 160Hz
dead-time:  2%

Uwe reduced the noise on the 90 degree detector (see previous elog entry)
  260   Mon Mar 23 19:32:53 2020 LaszloCalibrationrun112 - Xray90 calib Am241, distance 200mm - LESS NOISE 
Detector: 90
Source: 241Am
Distance: 200mm
Start time: 20:01:43 23.03.2020
Stop time:  

file name: run112_xxxx.lmd
avrg. rate: 444Hz
dead-time:  5%

Uwe reduced the noise on the 90 degree detector (see elog entry)
  261   Mon Mar 23 20:52:37 2020 LaszloCalibrationrun113 - Xray145 calib Am241, distance 305mm - LESS NOISE 
Detector: 145
Source: 241Am
Distance: 305mm
Start time: 20:01:43 23.03.2020
Stop time:  21:43:34

file name: run113_xxxx.lmd
avrg. rate: 220Hz
dead-time:  2.5%

Uwe reduced the noise on the 145 degree detector as well. 
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