Exploranium GR-135 - Stabilize

SAIC Exploranium – GR-135 System Manual page: 34
f) SCAN WINDOW : selections are TOT, ROI1, ROI2, ROI3
This selects the data used in the SEARCH mode. If TOT is selected then the display will show
TOTAL and the full spectrum data is used – everything above the lower threshold of 20keV
Any of the ROI selections utilize data ONLY FROM THIS ROI for the SEARCH mode. Settings for the
ROIs are explained in section 9.6. Thus with ROI1 at its default setting for Americium-241 – then if
ROI1 is selected then only the Americium data will be used for the SEARCH scan.
NOTE: users are advised that, in most cases, using the TOT selection is recommended as this
selection gives you the highest count-rate and therefore the highest sensitivity.
g) AVERAGING: selections are OFF,
3P, 5P, 10P
This selection permits data filtering. 3P = 3 point filtering – really a 3 point moving average. So at a
1 second base sample rate the data will be displayed at a 3 second average updated at a 1/sec rate.
This makes the data chart display smoother and easier to read but users are cautioned that
averaging also reduces small peaks amplitudes so if the instrument is rapidly moved then small peaks
may be missed.
OFF – raw data only, no data averaging
3P = 3 point averaging
5P = 5 point averaging
10P = 10 point averaging
10.2 STABILIZE
Selections are CZT FINE GAIN and RE-STAB MODE
10.2.1 CZT FINE GAIN
Set by Exploranium, see system CALIBRATION SHEET for the correct setting. The calibrated value
for this parameter is stored in system memory. When defaults are loaded the calibrated value is
automatically loaded
10.2.2 RE-STAB MODE
Selection currently are only S.VALIDITY
10.2.2.1 S. VALIDITY
Selections are OFF, 12H,
24H
This parameter is used to advise users when system re-stabilization is required in the AUTO mode
OFF - with this selection (in the AUTO mode) - when the unit is removed from the DS unit then the
correct Gain is maintained using the reference temperature correction. The OFF parameter
means that NO WARNINGS are given to the user of when a recommended stabilization in the DS
is required. This setting is often used by users who have no realistic capability of using the DS
prior to instrument deployment so would find the requirement to stabilize in the DS as
impractical. Users are advised that although the temperature correction is quite accurate under
some special conditions the accuracy of the correction may be inadequate. The rule of thumb is
that if during operation you get an “UNIDENTIFIED ISOTOPE” message then this is possibly
because the gain correction is a little off.