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after calibration
checkbox to mark it; this will disable ID Mode after an energy calibration until a new
background spectrum is collected.
4.15.2.3 Adding More Calibration Sources
Cs-137 and K-40 are defined by default as calibration sources. The selected source in the
Calibration sources
field tells the user which source is expected on the Calibrate screen (Figure 87). If the user wishes to add
other sources (up to a total of four) tap the
Setup
button to open the dialog shown in Figure 88.
Figure 87. Calibration Settings Screen
Figure 88. Define Calibration Sources
Tapping an empty cell in the table shown on this screen enables entry of a source name and energy. Good
candidates for additional energy calibration sources are Co-60 (1332.5 keV) and Th-232 (2615.5 keV for 208Tl
daughter). Low-energy sources (less than 500 keV), such as Ba-133, should be avoided because they force a
high fraction of the total energy range to be extrapolated instead of interpolated. If it is intended to use the
system with the gain stabilizer permanently disabled, then calibrating with Th-232 is highly recommended.
An optional Th-232 calibration source can be purchased for calibration of the Detective X (P/N DETECTIVE-X-
ACC-TH-CAL). Instructions for use of the calibration source can be seen in Appendix E.