Angle 5 brings grossly important new functionalities, providing not only for more accurate results, but also making work with Angle still easier and more intuitive.
The most important improvement Angle 5 brings is the support for the correction of spectroscopic effects of true coincidence summing (“Cascade summing corrections”, CSC). Namely, radionuclides decay in more or less complex ways (“decay schemes”, or “transition cascades”, or “cascades”), emitting (quasi)concurrent gamma-rays which populate various peaks in the spectrum (the latter being collected/created by the counting device). Hence a peak may be populated by more than one transition. This effect is called cascade summing or true coincidence summing.
For a given peak, originating from a characteristic gamma transition (gamma line) of interest, this may lead to either addition or loss of (expected) counts, anyhow “spoiling” the peak in analytical sense. Accounting for this effect represents the cascade summing correction (CSC). Calculation of CSC factors is, in principle, a pretty elaborate task. It is based on the knowledge of decay schemes of the nuclides of interest and detection efficiencies for the given counting arrangement. CSC factors do not depend on the source activity (as is the case, to the contrary, with random coincidences).
Cascade summing effects tend to diminish with increasing distance between the source and the detector, and become more prominent for close geometries (e.g. for “contact” measurements, or for Marinelli sources, or for well-type detectors), and can amount to tens of percent. As close geometries are practically obligatory for low activity measurements (most notably in environmental monitoring), the importance of proper CS corrections cannot be overestimated.
Starting with this version, Angle is replacing numerical integration with Monte Carlo method. This new approach is an important step we made in order to enable certain features, such as cascade summing corrections. Switching to Monte Carlo calculations allows more flexibility in developing various future improvements of the software.
Now it is possible to set the desired precision for the calculations more exactly. Users can define the calculation precision in percentages, instead of Gauss coefficients, which were used previously, and which were not very familiar to many users.
Now it is possible to export the calculation results to JSON and YAML formats. Support for these popular human-readable file formats for data interchange, apart from the XML format introduced with Angle 4, will enable easy integration with even more third-party applications.
The two popular graphics formats are added to the list of supported formats for exporting previews: PNG and SVG. PNG format is a lossless raster format, and the SVG is vector format, both widely used in the desktop, mobile and web applications.