Photocathode Holder Assembly With Fixed Lens Spacing
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Solution Overview
Problem
Existing electron guns with photocathodes require adjustments to maintain the distance between the photocathode film and the lens, leading to complex operations and increased device size and complexity due to the need for motion mechanisms and lens position adjustments.
Innovation Solution
A photocathode kit and electron gun design where the distance between the photocathode film and the lens is fixed by a spacer, eliminating the need for adjustments and simplifying the installation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photocathode is taken out of the vacuum chamber for EA surface treatment, then the photocathode can be treated, but the operation becomes complex and device size increases due to motion mechanisms and lens position adjustment
Solution Approach 1:
The invention extracts the photocathode treatment process from the vacuum chamber environment by providing a separate treatment chamber. The photocathode can be moved to the treatment chamber for EA surface treatment without requiring complex motion mechanisms inside the vacuum chamber, thus simplifying the overall device structure while maintaining treatment capability
Solution Approach 2:
The device is segmented into a vacuum chamber for electron beam generation and a separate treatment chamber for photocathode maintenance. This segmentation allows independent optimization of each function and eliminates the need for complex adjustment mechanisms that would be required if treatment were performed inside the vacuum chamber
2Ease of operation
If EA surface treatment is performed inside the vacuum chamber, then the photocathode can be treated without removal, but the lens becomes contaminated by vaporized surface treatment material
Solution Approach 1:
The harmful vaporized surface treatment material is extracted from the vacuum chamber environment by performing treatment in a separate treatment chamber. This prevents contamination of the lens while still allowing convenient photocathode treatment without removal from the overall device
Solution Approach 2:
The treatment chamber acts as an intermediary space between the photocathode storage location and the vacuum chamber. It provides a controlled environment for surface treatment that isolates the harmful vaporization process from the sensitive optical components in the vacuum chamber
3Manufacturing precision
If the distance between photocathode film and lens is adjustable, then excitation light focusing can be optimized, but the device size and complexity increase due to motion mechanisms
Solution Approach 1:
The optimal distance between the photocathode film and lens is predetermined during the design and assembly phase. The holder is manufactured with built-in spacing features that automatically maintain the correct distance, eliminating the need for adjustable mechanisms while ensuring optimal excitation light focusing
Solution Approach 2:
Instead of using complex adjustable mechanisms, the invention uses a simplified fixed structure that copies the optimal geometric relationship directly into the holder design. The spacing is built-in during manufacturing, replicating the ideal optical configuration without requiring active adjustment
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 simplifies the operation of installing the photocathode and lens inside the electron gun, reduces the device size, and eliminates the complexity of motion and lens position adjustment mechanisms.
Implementation Method 1
a spacer arranged between the photocathode and the lens, and defining a predetermined distance between the photocathode film and the lens
Implementation Method 2
a lens arranged inside the holder, downstream of the photocathode in the direction of light incident to the photocathode, the lens having a focal point located on the photocathode film
Implementation Method 3
the photocathode film is irradiated with excitation light from the light source, and electrons are emitted into vacuum from the photocathode film side
Data Source
Figure 1~2(c)
Figure 3~4A
Figure 4B~4C
AI summary
Provided is a photocathode kit that does not require adjustment of the distance between a photocathode film and a lens focusing on the photocathode film when the photocathode and the lens are installed inside an electron gun. The photocathode kit includes: a photocathode including a substrate in which a photocathode film is formed on a first surface; a lens; and a holder that holds the substrate and the lens, and the holder has a retaining member that retains the photocathode film and the lens to be spaced apart by a predetermined distance, and a first communication path that communicates between inside of the holder and outside of the holder.