BNC 970 Portable Multi-Channel Analyzer (MCA) - Manual (Page 51)

Model 970 Instruction Manual 48
5. If the ROI is one contained in the calibration source:
6. Select the nuclide for the ROI from the Associated Nuclide drop-down list.
7. Select the peak energy for the ROI from the Associated Peak drop-down list.
8. Enter the activity of the source being used in the Activity box.
9. Select the appropriate units from the Units drop-down list. NOTE: The units must be the
same for all isotope activities entered for the calibration!
10. If the ROI is not contained in the calibration source :
11. Check the Assign ROI as Unknown box.
12. Select the nuclide for the ROI from the Associated Nuclide drop-down list.
13. Select the peak energy for the ROI from the Associated Peak drop-down list.
14. Click on the ROI Eff. Cal! button.
15. Click on the Report button to view, save, or print the Efficiency Calibration report. This report
is available any time following the Efficiency Calibration, until replaced by a new Efficiency
Calibration.
6.7 Fine Tuning Hardware Settings
Prerequisites
This procedure assumes that an Energy Calibration has been performed.
Discussion
The Fine Tuning procedure provides an automated way of adjusting the Fine Gain to compensate
for small shifts in the spectrum due to changes in the temperature, etc., of the detector.
This procedure can also be done manually. In many cases, it is quicker to manually adjust the
Fine Gain setting.
Procedure
Click on the Fine button on the Button Bar. A small window will pop up and display an isotope
selection drop-down menu and an energy peak selection drop-down menu. The Hardware
Settings Panel will also open along the bottom of the Spectrum Display, but only the Fine Gain
Adjust (
± 64) will be active.
1. Select an isotope and an energy peak from the drop-down menus.
2. Click on the Fine Tune button. Note: The corresponding isotope source must be on the
detector in order for Fine Tuning to be successful.
3. A series of Acquisitions will follow until the most accurate Fine Gain adjustment is achieved.
This can take several minutes.
4. A “Fine Gain Adjustment Complete” message will appear when the procedure is done.