Ion Detector with Conversion Dynode and Avalanche Photodiode

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Solution Overview

Problem

Conventional ion detectors face challenges in improving detection accuracy due to afterglow from scintillators and complexity in structure, particularly in converting secondary electrons effectively.

Innovation Solution

An ion detector design that eliminates scintillators by using a conversion dynode with a negative potential and a semiconductor electron detector with an electron incident surface closer to the dynode, combined with an avalanche photodiode to enhance convergent properties of secondary electrons and reduce noise, thereby improving detection accuracy and simplifying the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If scintillators are used to convert secondary electrons to light, then detection capability is achieved, but afterglow occurs which deteriorates detection accuracy

Engineering Contradiction:

Improvedetection accuracyVSAvoidafterglow

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the scintillator component from the detection system. By directly detecting secondary electrons with a semiconductor electron detector, the harmful afterglow effect is eliminated while maintaining detection capability through a different physical mechanism (direct electron detection rather than light conversion)

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the optical conversion mechanism (scintillator converting electrons to light) with a direct electronic detection mechanism (semiconductor detector directly detecting electrons). This substitution eliminates the intermediate light conversion step that causes afterglow

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the electron incident surface is located closer to the conversion dynode, then the convergent property of secondary electrons is increased, but the distance reduction must be achieved without compromising detector support structure

Engineering Contradiction:

Improveconvergent propertyVSAvoiddistance between dynode and detector

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent positions the electron incident surface in a different spatial dimension relative to the conversion dynode, specifically placing it closer in the electron trajectory direction while using a stem structure to provide support from a different spatial location, thus achieving both short distance and proper support

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Speed

If the semiconductor electron detector is downsized to improve response characteristics, then detection speed is improved, but the detector area is reduced which may affect electron collection efficiency

Engineering Contradiction:

Improveresponse characteristicsVSAvoiddetector area

Core Design Contradiction:

SpeedVSArea of stationary object

Solution Approach 1:

The patent applies local quality by concentrating the detection function at the electron incident surface which is positioned optimally close to the conversion dynode. The stem structure provides support without interfering with the localized electron collection area, allowing small detector size while maintaining collection efficiency through optimal spatial positioning

Inventive Principle:

Principle #3Local quality

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 design increases the convergent property of secondary electrons, allows for a downsized detector, enhances response characteristics, and improves the signal-to-noise ratio, leading to improved detection accuracy and structural simplification.

Implementation Method 1

convention ion detectors including conversion dynodes that emit secondary electrons by ion collisions

Methodology Applied

Scientific EffectSecondary electron emission:

Implementation Method 2

the semiconductor electron detector may be an avalanche photodiode

Methodology Applied

Scientific EffectAvalanche breakdown: Avalanche Breakdown

Data Source

PatentUS8975592B2Ion detector

Publication Date: 2015.03.10 HAMAMATSU PHOTONICS KK

AI summary

An ion detector 1A for detecting positive ions is provided with a chamber 2 having an ion entrance 3 which allows positive ions to enter, a conversion dynode 9 which is disposed in the chamber 2 and to which a negative potential is applied, and an avalanche photodiode 30 that is disposed in the chamber 2 and has an electron incident surface 30a which is opposed to the conversion dynode 9 and also into which secondary electrons emitted from the conversion dynode 9 are made incident. The electron incident surface 30a is located closer to the conversion dynode 9 than a positioning part 14 which supports the avalanche photodiode 30 in the grounded chamber 2.