ORTEC Detective X, Руководство пользователя

Страница: 131 / 131

119
CALIBRATION INSTRUCTIONS
USING TUNGSTEN WELDING ELECTRODES P/N
DETECTIVE-X-ACC-TH-CAL FOR THE DETECTIVE-
X
Thoriated tungsten welding electrodes are a safe, convenient, and reliable very low activity source of gamma
rays for use in calibrating a Detective-X. A high energy line at 2614.5 keV is ideal for this purpose because of
its high energy allowing calibration to be interpolated for lower energy lines rather than extrapolated.
E.1 ADDING TH-232 TO THE CALIBRATION SOURCES TABLE
1. Click on the Settings button and then select the Cal Settings button to open the Calibration settings
screen (see Figure 87).
2. Click the Setup button to open the Calibration sources list (see Figure 88). Add Th-232 with an energy
of 2614.5 keV by tapping in an empty cell. Once complete, click the Back button.
3. Select the Calibration sources dropdown (see Figure 87) and select the Th-232 source that was added.
Select Back to return to the Settings screen.
E.2 CALIBRATING THE DETECTIVE X USING THE THORIUM
WELDING ELECTRODES (TH-232) P/N DETECTIVE-X-ACC-TH-
CAL
1. Place the Thorium Electrodes, P/N DETECTIVE-X-ACC-TH-CAL, in front of the instrument as to
maximize the gamma count rate.
2. Tap Settings , if not already in the settings screen, to open the Settings screen. Then tap the Calibrate
button to enter the Calibration screen (see Figure 86).
3. Tap Start Calibration Now . The acquisition will begin, and the spectrum will be displayed on the lower
left of the screen.
4. When enough counts have been accumulated to accurately determine the centroid of the Th-232
peak (may take several minutes), the system will report the degree of adjustment necessary. Tap Use
Improved Calibration to complete the process.
NOTE If the Back button is tapped before tapping Use Improved Calibration , the old calibration
will be retained and the new one will be discarded.