Cyclotron Ion Source Positioning for High Beam Current

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Solution Overview

Problem

Existing cyclotrons with twin ion sources face challenges in producing high beam currents and minimizing beam losses, as previous designs are complex, fragile, and inefficient, and auto-extraction methods fail to direct both beams simultaneously.

Innovation Solution

A cyclotron design with ion sources positioned at a larger radial distance to create coherent horizontal betatron oscillations, allowing for easier extraction and simultaneous use of two beams, featuring a 'deep valley' structure with auto-extraction and a beam separator to minimize activation and optimize magnetic field gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If ion sources are positioned closer to the center to reduce complexity, then device complexity is reduced, but beam losses increase and extraction becomes difficult

Engineering Contradiction:
Improveion source positioning complexityVSAvoidbeam losses
Core Design Contradiction:
Device complexityVSLoss of substance

Solution Approach 1:

The patent positions ion sources at a specific radial distance from the center (at a radius where the betatron oscillation amplitude equals the source radius), which optimizes the balance between device complexity and beam losses. This parameter optimization enables effective extraction while maintaining manageable system complexity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If traditional extraction methods are used with twin ion sources, then extraction is achieved for one beam, but the other beam cannot be extracted simultaneously

Engineering Contradiction:
Improvebeam extraction efficiencyVSAvoidsimultaneous beam extraction capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces asymmetry by positioning the two ion sources at opposite phases of betatron oscillation (180 degrees apart). This asymmetric positioning allows each beam to follow a distinct extraction path, enabling simultaneous extraction of both beams without interference, thereby doubling the productivity compared to traditional single-beam extraction methods.

Inventive Principle:
Principle #4Asymmetry

3Length of moving object

If ion sources are shifted towards the center to pass beams radially outwards, then beam path clearance is improved, but the gap between sources and Dee electrode becomes non-optimal

Engineering Contradiction:
Improvebeam path clearanceVSAvoidacceleration gap optimization
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent optimizes the radial position of ion sources to a specific value where the betatron oscillation amplitude equals the source radius. This parameter optimization simultaneously achieves adequate beam path clearance and maintains an optimal acceleration gap between the sources and Dee electrode, avoiding the trade-off present in previous designs.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If negative ions are produced and accelerated to increase beam current, then beam current is increased, but electron loss occurs leading to unwanted isotopes and activation

Engineering Contradiction:
Improvebeam currentVSAvoidunwanted isotopes and activation
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent utilizes the natural betatron oscillations of the cyclotron system to achieve spontaneous extraction of positive ions. The oscillation-induced turn separation automatically directs beams to extraction points without requiring additional stripping foils or complex extraction electrodes, thereby eliminating the harmful effects associated with negative ion acceleration while maintaining high beam current through dual-source operation.

Inventive Principle:
Principle #25Self-service

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 achieves high beam currents with reduced losses and allows for continuous operation by enabling efficient extraction and simultaneous use of two beams, minimizing the need for maintenance and increasing productivity.

Implementation Method 1

a Dee electrode assembly and a counter Dee electrode assembly separated from each other by a gap and means for submitting said Dee electrode assembly and counter Dee electrode assembly to a given accelerating voltage for accelerating said charged particles

Methodology Applied
Scientific EffectElectric field acceleration: Electric Field

Implementation Method 2

A cyclotron is a charged particle accelerator wherein particles are guided along a quasi-circular or spiral path around an axis by a magnetic field

Methodology Applied
Scientific EffectMagnetic field guidance: Magnetic Field

Implementation Method 3

The emerging positively charged particles are now deflected in the opposite direction by the magnetic field and directed outside of the cyclotron

Methodology Applied
Scientific EffectMagnetic field deflection: Lorentz Force

Data Source

PatentEP3024306B1High current cyclotron
Publication Date: 2019.08.07 ION BEAM APPL
  • EP3024306B1 patent drawingFigure 1
  • EP3024306B1 patent drawingFigure 2
  • EP3024306B1 patent drawingFigure 3

AI summary

Cyclotron for accelerating charged particles around an axis, comprising an electromagnet with an upper pole and a lower pole, producing a magnetic field in the direction of said axis; a Dee electrode assembly and a counter Dee electrode assembly separated from each other by a gap for accelerating said charged particles and a pair of ion sources (1, 2) located in a central region of the cyclotron. Said ion sources (1, 2) are located at a distance of said axis such that the particles emitted from the first ion source (1) pass between said first (1) and second (2) ion sources after a path of half a turn, and radially outwards of the second ion source (2) after a path of three half-turns, and reciprocally.