Ion Beam Profile Measurement Using Phosphor Screen Copying
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Solution Overview
Problem
Existing methods for measuring and controlling ion beam properties, such as grid harps and Faraday cups, are expensive, time-consuming, and provide incomplete or subjective data, making it difficult to achieve continuous and accurate measurement and control of beam uniformity and flux.
Innovation Solution
An apparatus comprising an array of Faraday cups with electrometers, multi-channel low-current scanner cards, and computational analysis software to calculate and display beam parameters in a 3-dimensional graphic format, enabling real-time monitoring and adjustment of ion beam properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If grid harps are used to measure beam intensity distribution, then measurement capability is provided, but device cost and complexity increase significantly
Solution Approach 1:
The patent uses phosphor screen to create a visual copy/image of the beam intensity distribution that can be captured by camera. Instead of directly measuring with complex grid harp, the system creates a luminous representation of the beam profile that is easier to detect and analyze, resolving the contradiction between measurement capability and device complexity
Solution Approach 2:
The phosphor screen acts as an intermediary between the charged particle beam and the detection system. It converts the beam intensity distribution into light intensity distribution, enabling measurement through optical means rather than direct electrical measurement, thus reducing device complexity while maintaining measurement capability
2Difficulty of detecting and measuring
If grid harps are used for beam measurement, then beam properties can be measured, but measurement time increases and data completeness decreases
Solution Approach 1:
The phosphor screen continuously displays the beam profile as long as the beam is present, allowing for continuous monitoring rather than discrete measurements. The camera can capture images at any time, enabling continuous useful action in beam measurement and reducing measurement time
Solution Approach 2:
The patent replaces the mechanical scanning system of grid harps with an optical field-based measurement using phosphor screen and camera. This substitution eliminates mechanical movement and scanning time, allowing instantaneous capture of the entire beam profile, thus reducing measurement time while maintaining comprehensive beam property measurement
3Loss of information
If grid harps are used, then some beam data can be obtained, but data completeness and quantitative accuracy decrease
Solution Approach 1:
The phosphor screen creates a complete visual copy of the entire beam cross-section, capturing all spatial information simultaneously. The camera records the complete intensity distribution pattern, providing comprehensive beam data including profile shape, intensity variations, and spatial characteristics without information loss, while keeping the device relatively simple
Solution Approach 2:
The system changes the measurement parameter from direct electrical current measurement (grid harp) to optical intensity measurement (phosphor screen luminescence). This parameter change enables capture of complete beam spatial distribution information through image intensity variations, providing comprehensive quantitative data while maintaining device simplicity
4Productivity
If visual information is provided for beam adjustment, then beam control efficiency improves, but measurement and display system complexity increases
Solution Approach 1:
The phosphor screen creates a direct visual copy of the beam profile that can be viewed or captured by camera. This visual representation provides intuitive feedback for beam adjustment without requiring complex data processing or display systems, improving beam control efficiency while keeping the display system relatively simple
Solution Approach 2:
The phosphor screen converts beam intensity information into visible light intensity variations, creating a visual display where different regions of the beam are represented by different brightness levels. This color/brightness encoding provides immediate visual feedback for beam uniformity and profile, enhancing control efficiency without increasing display system complexity
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 system provides reliable, quantitative data for continuous monitoring and adjustment of ion beam properties, improving the accuracy and efficiency of beam control and shaping.
Implementation Method 1
A Faraday cup is a detector that measures, at a fixed location, the current in a beam of charged particles. The cup would be placed in the path of the particle beam, and an electrical lead is attached which conducts the current to a measuring device. According to Gauss' Law, the charge collected on the Faraday cup is the induced charge.
Implementation Method 2
Each has its own unique construction, and both are used in a variety of applications, principally in connection with testing or manufacturing methods. A Faraday cup is typically connected to an electrometer to measure the current of the charged particles collected by the cup.
Data Source
AI summary
According to an embodiment, an apparatus for measuring the uniformity of a beam of charged particles at an exposure location includes a plurality of Faraday cups, each cup including an electrometer for determining the current collected by said cup, at least one multi-channel low current scanner card electrically coupled to the electrometers, a processor electrically coupled to said at least one scanner card, computational analysis software for receiving signals from said processor and calculating beam parameters, and display software for generating a graphical representation of the beam parameters calculated by said computational analysis software.