Wall-less Electron Multiplier Assembly Suppressing Leakage Currents

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Solution Overview

Problem

Conventional avalanche particle detectors experience leakage currents when operated with photosensitive vapors or in ambient air, particularly at high humidity levels, leading to spurious pulses and reduced detector performance, limiting their application in harsh environments.

Innovation Solution

An electron multiplier assembly with a gap between electrode plates supported by sparse spacer elements, eliminating dielectric insulator sheets and through-hole walls to suppress leakage currents, using non-conductive materials and grooved spacer elements to further reduce current formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If dielectric insulator sheets and through-hole walls are used to support electrode plates, then structural stability is improved, but leakage currents increase leading to spurious pulses and reduced detector performance

Engineering Contradiction:
Improvestructural stabilityVSAvoidleakage currents
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent removes the dielectric insulator sheet and through-hole walls from the electrode plate structure. Instead of using continuous dielectric materials, the invention employs sparse spacer elements that provide mechanical support without creating continuous paths for leakage currents, thereby eliminating the harmful dielectric surfaces while maintaining structural integrity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from solid dielectric insulator sheets to a porous-like structure with sparse spacer elements. This creates a structure that is mechanically supportive yet electrically discontinuous, allowing the electrode plates to be stabilized without providing continuous dielectric surfaces that generate leakage currents

Inventive Principle:
Principle #31Porous materials

2Ease of manufacture

If conventional GEM detector design with dielectric insulator sheets is used, then manufacturing simplicity is improved, but reliability in harsh environments deteriorates due to leakage currents at high humidity

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddetector reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent extracts the problematic dielectric insulator sheet component from the conventional GEM structure. By removing this continuous dielectric element and replacing it with sparse spacers, the design maintains manufacturing simplicity while dramatically improving reliability in harsh environments by eliminating the source of humidity-dependent leakage currents

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a composite structure combining conductive electrode plates with non-conductive spacer elements. This composite approach maintains ease of manufacture using standard PCB techniques while the non-conductive spacers provide the necessary electrical isolation without the leakage current problems of continuous dielectric sheets

Inventive Principle:
Principle #40Composite materials

3Strength

If through-holes with walls are used in electrode plates, then structural support is improved, but current formation along walls increases leakage

Engineering Contradiction:
Improvestructural supportVSAvoidcurrent formation
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent removes the through-hole walls from the electrode plate structure. Instead of drilling holes through the entire electrode plate thickness, the invention uses surface-mounted or partially embedded spacer elements that provide structural support at discrete locations without creating continuous wall structures where currents can form and flow

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the continuous through-hole structure into discrete, isolated spacer elements. This segmentation breaks the continuous path that would allow current formation along hole walls, while the distributed spacers still provide adequate structural support for the electrode plates

Inventive Principle:
Principle #1Segmentation

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

The solution effectively suppresses leakage currents, enabling reliable operation with various gases, including ambient air, and in harsh conditions, with improved detector stability and higher gas gains, allowing for versatile applications beyond high-energy physics.

Implementation Method 1

In the amplification gap, the primary electrons initiate an electron avalanche by impact ionization

Methodology Applied
Scientific EffectImpact ionization: Ionisation

Implementation Method 2

The strong amplification field which is necessary to initiate a Townsend avalanche comes from a thin wire at a positive high voltage potential

Methodology Applied
Scientific EffectTownsend avalanche: Townsend Discharge

Implementation Method 3

said first electrode plate is supported on said second electrode plate only by means of a plurality of spacer elements

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP2976778B1A wall-less electron multiplier assembly
Publication Date: 2019.09.18 EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
  • EP2976778B1 patent drawingFigure 1
  • EP2976778B1 patent drawingFigure 2
  • EP2976778B1 patent drawingFigure 3

AI summary

An electron multiplier assembly comprises a first electrode plate supported on a second electrode plate by a means of plurality of spacers. Through-holes are formed in the first electrode plate and in the second electrode plate and are carefully aligned so to form amplification channels in the gap between the first electrode plate and the second electrode plate. The amplification channels allow to convert primary electrons into an avalanche of electrons that may be detected with suitable readout means. The detector structure is wall-less in the sense that neighboring amplification channels are not separated by walls, which allows to reduce leakage currents and to provide a detector that can be used with a plurality of detector gases or even in humid ambient air.