Centroid Contact Germanium Radiation Detector

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Solution Overview

Problem

Current radiation detection systems, such as HPGe detectors, face deficiencies in capacitance, electric field uniformity, noise reduction, energy resolution, and charge collection due to non-optimal electrode designs, which limit their performance in various radiation detection applications.

Innovation Solution

The implementation of a centroid contact geometry with a centralized small area signal electrode, positioned at the center of the detector volume, provides a uniform 4π electric field distribution, reducing capacitance and noise while enhancing charge collection and energy resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional planar or coaxial electrode designs are used, then the detector structure is simple and easy to manufacture, but the capacitance is high and electric field uniformity is poor

Engineering Contradiction:
Improveelectrode structure simplicityVSAvoidenergy resolution
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent employs asymmetric electrode configuration where a small area centroid contact (0.5-2 mm diameter) is positioned at the geometric center of the detector volume, while the outer electrode forms a large area contact on the opposite surface. This asymmetric arrangement creates a 4π electric field distribution that improves charge collection efficiency and reduces capacitance compared to symmetric traditional designs, directly addressing the energy resolution limitation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention transitions from traditional 2D planar electrode arrangements to a 3D centroid contact configuration. By positioning the signal electrode at the three-dimensional centroid of the detector volume rather than on a surface plane, the electric field lines are optimized to converge radially from all directions (4π steradians), improving charge collection and reducing capacitance while maintaining manufacturability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If large area electrode contacts are used, then the charge collection area is increased, but the capacitance increases and noise increases

Engineering Contradiction:
Improvecharge collection efficiencyVSAvoidnoise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by concentrating the signal collection function at the centroid position with a small area contact (0.5-2 mm diameter), while the outer electrode provides the extended collection area. This localized signal contact minimizes capacitance and associated noise, while the distributed outer electrode maintains effective charge collection from the entire detector volume.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The electrode system is segmented into two distinct functional components: a small area centroid contact for signal collection that minimizes capacitance, and a large area outer electrode that maximizes charge collection area. This segmentation allows each component to optimize its specific function without the trade-offs inherent in single large-area contacts.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If non-centroid electrode positioning is used, then the manufacturing process is simpler, but the electric field uniformity and symmetry are reduced

Engineering Contradiction:
Improveelectrode positioning simplicityVSAvoidelectric field symmetry
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

By positioning the centroid contact at the geometric center of the detector volume, the patent creates equipotential symmetry in the electric field distribution. The 4π field configuration ensures that charge carriers experience uniform field strength and direction regardless of their position in the volume, improving charge collection efficiency and reducing position-dependent variations in signal amplitude.

Inventive Principle:
Principle #12Equipotentiality

4Device complexity

If traditional electrode designs are used, then the device complexity is low, but the energy resolution and noise performance are insufficient

Engineering Contradiction:
Improvedetector structure complexityVSAvoidenergy resolution
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs asymmetric electrode configuration where a small area centroid contact (0.5-2 mm diameter) is positioned at the geometric center of the detector volume, while the outer electrode forms a large area contact on the opposite surface. This asymmetric arrangement creates a 4π electric field distribution that improves charge collection efficiency and reduces capacitance compared to symmetric traditional designs, directly addressing the energy resolution limitation.

Inventive Principle:
Principle #4Asymmetry

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 results in improved energy resolution, reduced noise, and increased electric field strength, enabling more efficient radiation detection with lower capacitance and improved performance in large volume detectors, suitable for applications like dark matter research and neutrinoless double-beta decay projects.

Implementation Method 1

maintains stronger, more uniform, and symmetric electric fields in the device

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

systems and methods for the detection of radiation

Methodology Applied
Scientific EffectRadiation detection: Photoelectric Effect

Data Source

PatentEP3613086B1Centroid contact radiation detector system and method
Publication Date: 2022.01.26 CANBERRA INDUSTRIES INC
  • EP3613086B1 patent drawingFigure 1~2
  • EP3613086B1 patent drawingFigure 3~4
  • EP3613086B1 patent drawingFigure 5~6

AI summary

A centroid contact radiation detector system/method providing for low capacitance and noise insensitivity is disclosed, The system incorporates a P-type/N-type bulk germanium volume (PGEV/NGEV) having an internal well cavity void (IWCV). The external NGEV surfaces incorporate an N+/P+ electrode and the surface of the IWCV incorporates a centrally located P+/N+ contact (CPPC). The IWCV surface is constructed and the CPPC is positioned within the IWCV so as to provide uniform symmetric field distribution within the PGEV/NGEV and improved noise immunity. The CPPC may be formed using point, reduced-area, medium-area, large-area, hemispherical, semi-hemispherical, and cylindrical annulus contact constructions. The PGEV/NGEV may be constructed using cylindrical, regular polyhedral, or spherical forms.