Ion Source Vacuum Vessel Ion Contamination Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ion sources using laser beams for generating ion beams often contaminate the vacuum vessel with unintended ions such as hydrogen molecular ions and oxygen ions, which can lead to erroneous irradiation during applications like cancer treatment.
Innovation Solution
Incorporating an ion detector that monitors and outputs the number or mixing ratio of unintended ions within the vacuum vessel, allowing for real-time detection and control of the ion beam generation process, including the use of an operation-control signal processing circuit to stop the laser-ablation plasma generation when unintended ions exceed a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser beam is used to generate ion beams in a vacuum vessel, then ion beam generation capability is improved, but unintended ions (contaminants) are mixed into the vacuum vessel
Solution Approach 1:
The patent applies preliminary action by performing mass separation of ions before they are extracted from the vacuum vessel. The mass separator is positioned to separate unintended ions (contaminants) from intended ions prior to extraction, preventing contamination from occurring in the extraction region. This advance separation action resolves the contradiction by addressing the contamination issue before it affects the final ion beam quality
Solution Approach 2:
The patent applies the extraction principle by removing unintended ions from the mixture before extraction. The mass separator selectively extracts only the intended ions (e.g., C6+) while leaving unintended ions (contaminants) behind in the vacuum vessel. This selective extraction resolves the contradiction by ensuring that only pure ion beams are extracted, eliminating the harmful effect of contamination
2Quantity of substance
If unintended ions are present in the vacuum vessel, then ion beam output is increased, but beam quality and accuracy deteriorate
Solution Approach 1:
The mass separator performs preliminary separation of ions by mass before extraction. This preliminary action ensures that only ions of the desired mass (intended ions) are extracted, while ions of other masses (unintended ions) are left behind. This resolves the contradiction by maintaining high beam quality through selective extraction while still achieving sufficient ion beam output
Solution Approach 2:
The mass separator selectively extracts only the intended ions from the mixture of ions in the vacuum vessel. By taking out only the desired ion species based on their mass-to-charge ratio, the system maintains high beam quality and accuracy while still producing adequate ion beam output for practical applications
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
Prevents the extraction and output of unintended ions as part of the ion beam, ensuring the quality and accuracy of the ion beam for applications like cancer treatment by maintaining the intended ion composition.
Implementation Method 1
An ion source irradiates a target in a vacuum vessel with a laser beam and vaporizes and ionizes elements of the target with the energy of the laser beam to generate plasma (laser-ablation plasma)
Implementation Method 2
vaporizes and ionizes elements of the target with the energy of the laser beam to generate plasma
Data Source
AI summary
A laser-ablation plasma generator generates laser-ablation plasma from a target in a vacuum vessel. An ion beam extractor generates an ion beam by extracting ions included in the laser-ablation plasma from the vacuum vessel. An ion detector detects unintended ions other than intended ions, which are obtained by ionizing the elements in the target, out of ions in the vacuum vessel and outputs a detection signal representing a value which is a number of the unintended ions or a mixing ratio of the unintended ions to the intended ions as a detection result. The ion source using the laser beam makes it possible to normally monitor unintended ions other than intended ions out of ions in the vacuum vessel.