Pixelated Electrode Radiation Detector Inversion Reduces Polarization

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Solution Overview

Problem

Conventional direct conversion radiation detectors experience polarization effects and non-linear response at high count rates due to hole trapping, leading to reduced charge collection efficiency and compromised energy resolution, especially when dealing with high flux X-ray sources.

Innovation Solution

The use of pixelated electrode members on the radiation-receiving face of the detector, coupled with a planar electrode on the opposite side, allows for reduced polarization effects and a more linear response by reversing the standard irradiation configuration, enabling effective charge collection and improved energy resolution at high flux rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional direct conversion detectors are used with high flux X-ray sources, then the detector can operate at high count rates, but polarization effects increase causing non-linear response and reduced charge collection efficiency

Engineering Contradiction:

Improvecount rateVSAvoidpolarization effect

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent inverts the conventional detector configuration by placing pixelated electrodes on the radiation-receiving face rather than on the opposite face. This inversion reverses the direction of charge drift and eliminates the polarization effect that causes non-linear response at high count rates, while maintaining the ability to operate at high flux rates from X-ray tube sources

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If pixelated electrodes are placed on the radiation-receiving face, then polarization effects are reduced, but the detector structure becomes more complex

Engineering Contradiction:

Improvepolarization effectVSAvoidelectrode configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the electrode structure into multiple pixelated elements on the radiation-receiving face. This segmentation approach reduces polarization effects by creating multiple charge collection points, while the modular nature of the segmented electrodes makes the complexity manageable and the fabrication process controllable

Inventive Principle:

Principle #1Segmentation

3Device complexity

If conventional electrode configuration is used, then the detector structure is simple, but energy resolution is compromised at high count rates

Engineering Contradiction:

Improveelectrode configurationVSAvoidenergy resolution

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

By inverting the electrode configuration and placing pixelated electrodes on the radiation-receiving face, the patent improves energy resolution at high count rates. The inversion changes the charge drift path to eliminate polarization-induced energy loss, while the pixelated structure provides precise spatial charge collection that maintains excellent energy resolution even at high flux rates

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration significantly reduces polarization effects and achieves a more linear response in current mode, maintaining signal strength and energy resolution even at high count rates, enhancing the detector's performance with X-ray tube sources.

Implementation Method 1

Direct conversion radiation detectors, e.g., radiation detectors using Cadmium Zinc Telluride (CZT) or some other direct conversion material

Methodology Applied

Scientific EffectDirect conversion: Photoelectric Effect

Implementation Method 2

A potential 18 is applied across these two contacts 12, 14 to establish an electric field in the bulk of the detector. This field is employed to cause the carriers to drift to their respective electrode.

Methodology Applied

Scientific EffectCharge drift: Electric Field

Implementation Method 3

These sources typically supply much higher fluence than gamma sources... which has a significant effect on how these photons interact with the detection material.

Methodology Applied

Scientific EffectRadiation absorption: Absorption (EM radiation)

Data Source

PatentUS8084746B2Radiation detector and detection method having reduced polarization

Publication Date: 2011.12.27 MULTI DIMENSIONAL IMAGING

AI summary

A direct conversion radiation detector includes a detector body made from a direct conversion material, a plurality of segmented electrode members operatively coupled to a radiation-receiving side of the detector body and at least one electrode operatively coupled to a second side of the detector body. The radiation detector is configured such that received radiation is incident on the segmented electrode members. The radiation detector provides reduced polarization effects for a variety of high flux radiation detection applications.