Electron Cyclotron Resonance Ion Generator Segmentation
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Solution Overview
Problem
Conventional electron cyclotron resonance ion sources have low ionization efficiencies for condensable elements due to their tendency to stick to the chamber walls, leading to significant losses and reduced production of mono-charged or multi-charged ions.
Innovation Solution
An electron cyclotron resonance ion generator with a vacuum-tight chamber having two distinct zones: a first ionization stage where ions are generated with a magnetic field parallel to the longitudinal axis, and a second confinement stage that ensures the ions migrate to maintain a continuous plasma, enhancing ionization efficiency by minimizing wall interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ECR ion sources are used with a single chamber design, then the device structure is simple, but the ionization efficiency for condensable elements is low due to wall sticking losses
Solution Approach 1:
The single chamber is divided into two distinct zones: a first ionization zone where neutral atoms are ionized, and a second confinement zone where ions are confined and heated. This segmentation allows the ionization process to be separated from the confinement process, enabling efficient ionization of condensable elements before they can stick to walls, while maintaining a manageable device structure.
Solution Approach 2:
A virtual separator (magnetic field configuration) acts as an intermediary between the ionization zone and confinement zone, guiding ions from the first zone to the second zone without physical contact. This intermediary structure enables efficient ion transport while minimizing wall interactions that cause sticking losses.
2Productivity
If the chamber volume is increased to reduce wall interactions, then ionization efficiency improves, but the vacuum system complexity and pumping requirements increase
Solution Approach 1:
By segmenting the chamber into two functional zones with a virtual separator, the effective path length for ions is increased without proportionally increasing the physical chamber volume. This allows more time for ionization to occur while maintaining a compact overall structure that does not require excessive vacuum pumping capacity.
Solution Approach 2:
The patent uses magnetic field confinement in the radial direction to extend the effective interaction path of ions with the plasma, compensating for limited axial chamber length. This dimensional approach allows efficient ionization in a compact volume without requiring large chamber dimensions that would demand complex vacuum systems.
3Productivity
If magnetic field confinement is strengthened to reduce ion losses, then ionization efficiency improves, but the energy consumption increases
Solution Approach 1:
The magnetic field configuration is segmented into different strengths in different zones: a weaker field in the ionization zone to minimize energy consumption while allowing efficient ionization, and a stronger field in the confinement zone to reduce losses. This zoned approach optimizes the balance between ion production and energy usage.
Solution Approach 2:
The virtual separator creates a continuous magnetic field configuration that guides ions from ionization to confinement without interruption. This continuous action ensures that ions remain confined and heated efficiently throughout their residence time, maximizing ion production while maintaining reasonable energy levels through optimized field geometry.
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 solution significantly increases ionization efficiency by reducing the time for neutral particles to transform into ions, allowing for higher production of mono-charged or multi-charged particles before they can stick to the walls, particularly benefiting condensable elements and radioactive ions.
Implementation Method 1
The principle of these ECR sources is to couple, inside a vacuum-tight chamber supplied with atoms, a high-frequency wave with a B magnetic field, in such a way as to obtain the conditions under which a cyclotron resonance is capable of appearing and ionising the atoms present, thus generating a plasma.
Implementation Method 2
Provision is made to confine in the chamber the ions formed as well as the electrons used for their ionisation. This is achieved by superimposing on the magnetic field with an axial symmetry a magnetic field with a radial symmetry. The electrons of the plasma are trapped axially and radially in a magnetic potential well.
Implementation Method 3
The superposition of the radial magnetic field and the axial magnetic field leads to the formation of closed equimodulus surfaces of the magnetic field which do not have any contact with the walls of the chamber.
Implementation Method 4
A positive field gradient is created in all directions (along the axis and towards the wall of the chamber) and is a decelerator.
Data Source
AI summary
An electron cyclotron resonance ion generator includes a vacuum-tight chamber configured to contain a plasma, a magnetic field generator configured to generate a magnetic field in the chamber, a waveguide configured to propagate a high-frequency wave inside the chamber, a first ionization stage located at one end of the chamber, the first stage including an ionization zone in which ions are generated, the magnetic field being approximately parallel to a longitudinal axis in the ionization zone, a second magnetic confinement stage for the ions generated in the ionization zone, the second stage using a first high-frequency wave being propagated in the chamber from the waveguide, the magnetic field being approximately parallel to the longitudinal axis between the ionization zone and the second confinement stage, such that the ions generated in the ionization zone migrate towards the second confinement stage and the first and second stages contain the same continuous plasma.