HPGe Detector Cross Talk Compensation via Signal Subtraction
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Solution Overview
Problem
High brilliance X-ray flux leads to degradation in energy resolution and peak-to-background ratio in X-ray fluorescence spectroscopy due to pixel-to-pixel cross talk in semiconductor detectors, particularly in monolithic segmented HPGe detectors.
Innovation Solution
A signal processing algorithm that corrects for pixel-to-pixel cross talk by generating and applying energy-normalized cross talk signatures to adjacent pixels, using a digital pulse processor to identify and characterize cross talk profiles, and then scaling and synchronizing these signatures with the main pixel signals to compensate for cross talk effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of pixels in a given solid angle is increased to handle increasing X-ray flux, then the detector can process higher flux without saturation, but pixel-to-pixel cross talk increases leading to degraded energy resolution and peak to background ratio
Solution Approach 1:
The patent extracts and removes the harmful cross talk signals from the detector output by identifying characteristic cross talk signatures and subtracting them from the raw pixel signals, thereby eliminating the degradation in energy resolution while preserving the high flux processing capability
Solution Approach 2:
The patent implements a feedback mechanism where cross talk signatures are continuously identified from low radiation rate data and used to correct high radiation rate measurements, creating a closed-loop system that maintains measurement precision across varying flux conditions
2Productivity
If the count rate per pixel is increased to improve productivity, then more X-ray events can be detected, but energy resolution and peak to background ratio degrade considerably
Solution Approach 1:
The patent performs preliminary identification and characterization of cross talk signatures under low radiation rate conditions before processing high count rate data, preparing the correction parameters in advance to enable accurate subtraction during high flux operation
Solution Approach 2:
The patent converts the harmful cross talk effect into a beneficial correction mechanism by using the characteristic cross talk signatures observed at low rates to develop algorithms that actively compensate for and eliminate cross talk at high rates, thereby improving peak to background ratio
3Measurement precision
If cross talk correction algorithms are applied to improve energy resolution, then measurement precision improves, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent changes the parameter representation of cross talk from a complex multi-dimensional problem to a simplified set of characteristic signatures that can be stored and applied through straightforward mathematical operations, reducing processing complexity while maintaining correction effectiveness
Data Source
AI summary
The invention relates to signals representing energy of photons or particles of ionizing radiation incident on pixels of a semiconductor detector. Cross talk between the signals from different pixels is compensated using cross talk compensation signatures in the form of time domain series or functions which are aligned and applied to the cross talk signal in accordance with timing of the event which gave rise to the cross talk.