ORTEC Detective X, Руководство пользователя

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ORTEC
®
Detective
®
X Handheld Radioisotope Identifier 1107231N / 082020
66
By default, the system will continue to acquire background data until the operator specifically ends the
acquisition recognizing that more time is better. In some instances, this behavior may not be preferred. The
longer data is acquired prior to saving, the more opportunity exists for things to go wrong (such as a coworker
passing by the instrument with a check source in hand or batteries expiring). This screen allows the system
to be configured to automatically end and save background data once the minimum time has elapsed.
Figure 83. Background Settings
For special cases, the gain stabilizer can be completely disabled from this screen. Gain stabilization is highly
recommended where ID performance is important. However, if spectral data is being collected simply for
analysis by a Reachback organization, where known and blank spectra are
collected along with spectra from the object of interest, ID performance is
less important and gain stabilization across these measurements becomes
an undesired data collection parameter change.
When saving background data for an instrument that is equipped with a
neutron detector, a check is made that the measurement background is
statistically in line with the previous background measurement. If the
current measurement is significantly lower or higher than the previous
measurement, a message will be posted stating such (Figure 84). The
message may indicate there is a neutron source in the vicinity (perhaps a
test source that is not well shielded in its container). This message is also
typically displayed when new background data is measured at a different
altitude than a previous measurement.
4.15 SYSTEM ENERGY CALIBRATION
4.15.1 A Brief Introduction to Gain Stabilization
The Detective X typically maintains near-perfect energy calibration by relying on environmental K-40, which
produces a dependable gamma-ray peak at 1460.75 keV. The Detective X automatically adjusts the detector’s
amplifier gain to keep this reference peak in a known region of the spectrum histogram. With the
1460.75-keV peak in a known location, the software “knows” the relative positions of all other gamma rays
in the Identification Table.
Figure 84. Neutron Background
Changed