Detector Module Guard Band for Leakage Current Reduction
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Solution Overview
Problem
Radiation detectors, such as Cadmium Zinc Telluride (CZT) detectors, suffer from leakage currents and false events due to humidity forming between components, leading to reduced image quality and reliability in imaging systems.
Innovation Solution
The implementation of a detector module with a guard band covering the sidewalls and a cathode plate with underfill injection openings to reduce electron-hole recombinations and eliminate humidity-induced voids, along with a high-voltage strip design that minimizes condensation areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If components are closely spaced to enable multiple detectors on a single board, then device integration and productivity are improved, but electrical isolation between components deteriorates leading to leakage currents and false events
Solution Approach 1:
A guard band structure is introduced as an intermediary element between closely spaced detector components. The guard band includes a first portion coupled to sidewalls of the detector and a second portion coupled to a surface of the detector, creating an intermediate barrier that prevents direct electrical contact between adjacent components while allowing them to remain closely spaced on the same board.
2Reliability
If humidity forms between components, then electrical isolation is reduced, but leakage currents and false events increase
Solution Approach 1:
The guard band structure is installed in advance to prevent humidity-induced leakage currents before they can occur. By establishing an intermediate barrier between components, the guard band proactively blocks the formation of conductive humidity paths, thereby preventing leakage currents and false events from developing.
3Reliability
If a guard band is added to reduce leakage currents, then electrical isolation and reliability are improved, but device complexity increases
Solution Approach 1:
The guard band is segmented into a first portion coupled to sidewalls and a second portion coupled to a surface of the detector. This segmentation allows the guard band to be integrated into existing detector structures without requiring complete redesign, thereby improving electrical isolation while minimizing the increase in overall device complexity.
4Ease of manufacture
If components are closely spaced, then manufacturing efficiency is improved, but manufacturing precision requirements increase to maintain electrical isolation
Solution Approach 1:
The guard band structure is incorporated during the manufacturing process as a preliminary protective measure. By pre-installing the guard band between components during assembly, the system maintains electrical isolation without requiring extremely tight tolerances on component spacing, thus preserving manufacturing efficiency while reducing precision requirements.
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 effectively reduces false events and leakage currents, enhancing image quality and reliability by ensuring better electrical insulation and filling potential voids with underfill material.
Implementation Method 1
the guard band configured to reduce electron-hole (e-h) recombinations proximate to the edges of the detector
Implementation Method 2
a cathode plate attached to the first surface, the cathode plate including a plurality of underfill injection openings extending there-through, the underfill injection openings configured to receive an underfill material therethrough
Data Source
AI summary
A detector module for detecting photons includes a detector formed from a semiconductive material, the detector having a first surface, an opposing second surface, and a plurality of sidewalls extending between the first and second surfaces, and a guard band coupled to the sidewalls, the guard band having a length that extends about a circumference of the detector, the guard band having a width that is greater than a thickness of the detector such that an upper rim segment of the guard band projects beyond the first surface of the detector, the upper rim segment being folded over a peripheral region of the first surface along the circumference of the detector, the guard band configured to reduce recombinations proximate to the edges of the detector.