Photomultiplier Tube Dynode Groove Segmentation
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Solution Overview
Problem
Conventional photomultiplier tubes experience a decrease in withstand voltage due to electrons being incident on the surface of the insulating substrate between dynode stages, leading to electrical charging.
Innovation Solution
A photomultiplier tube design featuring a casing with a substrate having a flat surface made of insulating material, where electron multiplying stages are spaced apart and fixed on raised parts adjacent to insulating grooves, preventing electrons from reaching the substrate surface between stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrons are allowed to pass between adjacent stages of the electron multiplying part, then electron multiplication function is achieved, but electrons are incident on the insulating substrate surface causing electrical charging and decreased withstand voltage
Solution Approach 1:
The insulating substrate surface is segmented into multiple regions by grooves, creating isolated zones between adjacent electron multiplying stages. This segmentation prevents electrons from traveling across the substrate surface by dividing the continuous surface into separated segments bounded by the grooves.
Solution Approach 2:
The grooves act as intermediary structures between adjacent electron multiplying stages, providing a physical barrier that mediates the interaction between electrons and the insulating substrate. The grooves intercept electrons before they can reach the substrate surface, serving as a protective intermediary layer.
2Reliability
If grooves are formed between adjacent stages of electron multiplying part, then electron incidence on substrate is prevented, but device structure becomes more complex
Solution Approach 1:
The groove structures extend into the depth dimension of the substrate, creating three-dimensional features that provide effective electron blocking without requiring extensive lateral space. By utilizing the vertical dimension, the design achieves protection functionality while maintaining a compact planar footprint.
Solution Approach 2:
The grooves are formed as thin film structures within the insulating substrate, providing effective electron blocking with minimal material thickness. This thin-film approach achieves the protective function while minimizing the addition of structural complexity and maintaining substrate integrity.
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 design effectively prevents electron incidence on the substrate, maintaining high withstand voltage and reducing noise and voltage hysteresis, while improving processing efficiency by eliminating the need for masks during production.
Implementation Method 1
a photocathode which is installed on the first end side so as to be spaced away from the electron multiplying part, converting incident light from outside to photoelectrons
Data Source
AI summary
A photomultiplier tube including a casing having a glass substrate with a main surface made with an insulating material, dynodes having a 1st stage to an Nth stage which are arrayed to be spaced away sequentially from a first end side to a second end side on the main surface, a photocathode installed on the first end side to be spaced away from the 1st stage dynode to emit photoelectrons, and an anode part installed on the second end side to be spaced away from the Nth stage dynode, wherein a groove is formed between two adjacent dynodes on the main surface of the glass substrate, and the 1st stage to the Nth stage dynodes are fixed on raised parts adjacent to the grooves.