Exploranium GR-135 - Page 55

SAIC Exploranium – GR-135 System Manual page: 55
A.13 AUTOMATIC CZT DETECTOR ACTIVATION
The system has a special high sensitivity detector located inside. Special analysis determines the
special case where using such a detector will improve system analysis. If this occurs the actual
operation will be as follows:
- Unit takes the normal 55 second analysis and computes the
results
- Normally the Nuclide ID results are displayed
- However if the analysis determines that CZT is required the
unit will:
- beep 3 times as a warning
- automatically change detectors
- the display will show DET=CZT and a pop-up menu
(see fig) will appear to warn the user that CZT data
analysis will now take place.
- position the detector as required (see figure)
- press ENTER to start the automatic CZT analysis
- at the end of the CZT count period, the CZT spectra is stored and this spectrum #
is shown on the display as usual. Note that the original NaI spectrum was also
stored so at the end of the CZT spectrum period, the displayed stored spectrum #
is for the CZT and the one before is the NaI spectra. Thus if after CZT analysis
the spectra is stored as SPECTRUM #9 then SPECTRUM #8 is the related NaI
spectrum
- after data storage the spectra from the NaI and CZT are automatically analyzed
and the combined result shown to the user on the display
NOTE
CZT ANALYSIS IS REQUIRED UNDER SPECIAL CONDITIONS WHERE IT IS
POSSIBLE THAT SNM MATERIAL IS PRESENT. THE CZT DETECTOR IS A
RELATIVELY HIGH RESOLUTION DETECTOR AND THUS USING ITS DATA CAN
ENHANCE DATA ANALYSIS. HOWEVER IT IS VERY INSENSITIVE SO A LONG
COUNT TIME IS REQUIRED SO THE SYSTEM IS USUALLY SET FOR A 5 MINUTE
CZT COUNT TIME. 5 MINUTES IS A LONG TIME TO HOLD THE INSTRUMENT
AGAINST SOMETHING SO MOST USERS PREFER TO PROP THE UNIT IN PLACE
DURING THIS LONG ANALYSIS PERIOD. ALSO THE CZT DETECTOR IS LOCATED
AT THE BOTTOM OF THE INSTRUMENT SO THE INSTRUMENT SHOULD BE
POSITIONED ACCORDINGLY
GR-135
OPTIMUM
NAI ANALYSIS
DIRECTION
OPTIMUM
CZT ANALYSIS
DIRECTION
CZT DETECTOR
ACTIVATED
ENTER TO
START CZT
MESSAGE