![]() When all measurements are properly fitted, similar statistics will be displayed about them at the right side of the Main Module window as you can see in this picture.
To ease the work of the spectroscopist, the same peak evaluations may be utilized for nonlinearity determination and for efficiency analysis.
|
![]() Open Analyses node under your project, then click on Efficiency analyses and select Create new efficiency analysis task.
A new window appears now, where basic parameters of efficiency fitting algorithm may be specified.
|
![]() Here you can specify a descriptive name of the new efficiency analysis, and thresholds for the identification of peaks.
The Peak identification limit is used when peaklist peaks and nuclear library peaks are matched.
If the difference between peak centroid and radiation's energy is below this Chi value (using the combined energy uncertainty value of the peak and gamma line), the peaks will be considered as matching.
|
![]() The Detector efficiency evaluator window appears now with the empty Input data sheet.
Click Add measurement button at the right. The Measurement selector window appears now.
|
![]() Select all of HyperLab's example measurements from the project.
When you click OK in the measurement selector window, HyperLab performs the steps as follows.
|
![]() If enough data points are identified, the fit will succeed and the tab Fit becomes active, displaying the fitted efficiency curve.
It will be an absolute efficiency curve if any of the matching measurements has an absolutely calibrated source, and it will be relative efficiency if no measurement has such source.
Now you can add other measurements to the fit one-by-one, or more at a time. Eventually, a multi-measurement, multi-isotope efficiency curve may be easily constructed.
|
![]() It is better to check the residuals now, to see which line exactly causes this problematic RXSQ:. Click on the outlier point at 59keV. It is immediately displayed on the right that it belongs to 241Am.
In order to see the spectrum's details, save the efficiency fit, and open the 241Am peak evaluation.
|
![]() If you have a warning about that this peak evaluation is already used in an analysis, therefore cannot be modified, then select No here.
|
![]() Now select the Make a clone task while the peak evaluation is selected, thus creating a new peak evaluation, which contains the same details as its original one, but editable.
After cloning, a second peak evalution appears on the left, at the database tree.
For the sake of clearer further explanations, we changed its name to 2nd Peak evaluation.
|
Open this new evaluation, and check the problematic 59keV region.
|
![]() The problem is immediately apparent: the automatic fit incorrectly included part of the background in the peak.
Move the left side of the region to right, by dragging the blue arrow to the base of the peak.
|
![]() After the manual intervention, the area of the peak decreases significantly (change is over 5%, while its uncertainty was 1%). Now save this peak evaluation.
Open the efficiency analysis again.
|
![]() On the input page, open the 241Am measurement, select on the left the second peak evaluation, then click the Select evaluation button on the right.
|
![]() After removing two other low-energy lines, the figure shows the improved efficiency curve. It has RXSQ value of 2.7, which indicates a good fit – with only minimum user intervention.
If you have used the cloned peak evaluation, then the original one is possibly unused now, so you can delete it under the measurement entry.
|