UltraLo-1800 Alpha Particle Counter
XIA LLC
Page 68
VIII.
Alpha Analysis Engine
A.
Introduction
The software responsible for analyzing and classifying traces is called the “Alpha Analysis Engine”, or
AAE for short. The goal of AAE is to identify alphas, and it does this by progressively eliminating non-
alpha events based on their characteristics. If an event passes every elimination test (such tests are
typically called “cuts”), it is classified as an alpha.
B.
Overview
In brief, the algorithm takes the following steps:
1.
Prescreener: A quick fit to both traces that classifies them individually based on amplitude, if
the resulting classification pair indicates a potential alpha, pass trace to Level One. If there’s
no potential alpha, the analysis of the event is finished.
2.
Level One: A more robust, least-squares fit of both traces with cuts based on amplitude,
risetime, and other timing results. A test for “induction” on the traces is performed, and if
any is detected, pass to Level Two. If none is detected, the analysis of the event is finished.
3.
Level Two: Another least-squares fit, but now modeling a pulse with “induction”. Performs
“add-back” to get more accurate results on the anode, and applies Level One cuts again.