Multistage Dynode Columnar Structure for Luminescence Noise Suppression
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Solution Overview
Problem
Conventional compact photomultipliers experience unwanted luminescence noise due to secondary electrons impinging on insulating substrates, degrading signal-to-noise ratio and electron multiplication rate.
Innovation Solution
The design incorporates multistage dynodes with columns and pedestals arranged to minimize secondary electron emission surfaces' width and optimize their shape, reducing collisions with insulating surfaces and increasing the distance between dynodes, thereby suppressing luminescence noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If compact photomultiplier design is implemented with conventional planar structure, then device miniaturization is achieved, but secondary electrons impinge on insulating substrate causing luminescence noise
Solution Approach 1:
The dynode structure is segmented into multiple columns spaced apart from each other, rather than using a conventional planar configuration. This segmentation prevents secondary electrons from traveling directly to the insulating substrate, thereby reducing luminescence noise while maintaining compact device dimensions.
Solution Approach 2:
The invention transitions from a two-dimensional planar arrangement to a three-dimensional columnar structure with pedestals. The columns extend in the vertical direction perpendicular to the substrate, creating additional spatial dimensions that redirect electron trajectories away from the insulating substrate surface.
2Volume of moving object
If dynodes are arranged close together for compact size, then device miniaturization is achieved, but electron multiplication efficiency decreases due to increased noise
Solution Approach 1:
The columnar dynodes are designed with specific local geometries including tapered sides and spaced-apart structures. These local structural qualities create controlled electric field distributions that guide electron multiplication along desired paths while preventing stray electrons from reaching the substrate, thereby maintaining high signal detection accuracy in compact dimensions.
3Ease of manufacture
If conventional planar dynode structure is used, then manufacturing simplicity is maintained, but luminescence noise from substrate collisions increases
Solution Approach 1:
The dynode is divided into multiple discrete columns that can be fabricated using standard microfabrication techniques such as photolithography and etching. This segmented approach maintains manufacturing simplicity while effectively preventing secondary electron collisions with the substrate, thereby reducing luminescence noise.
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 unwanted luminescence, enhances signal detection accuracy, and improves the electron multiplication rate while maintaining the compact size of the photomultiplier.
Implementation Method 1
multistage dynodes which are arranged in series along a first direction on a predetermined installation surface, and on the installation surface and which implement cascade multiplication of electrons
Data Source
AI summary
The present invention relates to an electron multiplier and others to effectively suppress luminescence noise, even in compact size, in which each of multistage dynodes has a plurality of columns each having a peripheral surface separated physically, and in which each column is processed in such a shape that an area or a peripheral length of a section parallel to an installation surface on which the electron multiplier is arranged becomes minimum at a certain position on the peripheral surface in the column of interest.