ORTEC Detective X, Руководство пользователя

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1107231N / 082020 4. DETECTIVE X APPLICATION
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When radioactive nuclides are identified during the search process, the IDs appear in the section
below the strip charts. Note the Co-60 identification in Figure 48. These IDs are present as long as
the material remains in the detector field of view, then are removed from the screen.
4.6.1 The Signal Index
The Signal Index reflects the level of the gamma ray flux, as the detector receives more or fewer gamma ray
interactions the signal index increases and decreases.
Figure 49. Signal Index Strip Chart History and Current Level
The Signal Index (Figure 49) is based on the total background-subtracted gamma-ray count rate for all threat
and innocent nuclides, as well as gamma rays emitted by radionuclides that may not be included in the
software’s identification table. The vertical scale is logarithmic, and the peak height increases as the distance
between the Detective X and a gamma-ray source decreases (whether the operator is moving closer to the
source or vice versa). The index value on the right is dimensionless and is provided for comparison purposes
only. The horizontal scale is linear in time for a total time of 15 seconds.
When a nuclide ID alarm is generated, the background color for that section of the chart will change from
white to red for a threat ID, green for an innocent ID, or yellow for a suspect ID. This background color will
persist for as long as the radionuclide is present in the detector’s field of view. Note that suspect IDs are only
generated when the LCX analysis mode (Section 4.6.5) is enabled.
4.6.2 The SNM Index
The SNM Index is a function of the maximum confidence factor (Q value) for all SNM indicators in the
Identification Table. These include U, Pu, Np, Am, and neutrons. The SNM Index (Figure 50) works the same
way the Signal Index does, but is filtered to reflect only those gamma (and neutron) IDs characteristic of the
Special Nuclear Material radionuclides in the ID tables.
Figure 50. SNM Index Strip Chart History and Current Level
4.6.3 Identification (IDs) Box
The IDs Box (Figure 51) lists all nuclides currently in the detector’s field of view.
IMPORTANT These strip charts are indirect indicators to be used as quick visual tools, not as count-
rate or dose-rate meters for the protection of human health!