Magnetic Field Flutter for Vertical Focusing in Particle Accelerators

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Solution Overview

Problem

Particle accelerators, such as synchrocyclotrons, face challenges in maintaining effective vertical focusing of particle beams due to magnetic field bowing at the edges of the cavity, which disrupts the beam's orbital stability and requires compensatory RF voltage sweeps, and existing solutions do not adequately address these issues.

Innovation Solution

The implementation of magnetic field flutter through ferromagnetic arrangements, such as 'flutter bricks,' which introduce radial magnetic field fluctuations to counteract the effects of magnetic field bumps and bowing, ensuring vertical focusing and reducing the need for extensive RF voltage sweeps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If magnetic field bump is introduced to change particle orbits for extraction, then particle extraction is enabled, but vertical focusing is reduced

Engineering Contradiction:
Improveparticle extractionVSAvoidvertical focusing
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The ferromagnetic arrangements are positioned to preemptively counteract the loss of vertical focusing caused by the magnetic field bump. By introducing magnetic field flutter at the location of the ferromagnetic arrangements, the system anticipates and compensates for the focusing loss before it significantly degrades beam quality, thereby maintaining both extraction efficiency and vertical focusing.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The ferromagnetic arrangements act as an intermediary element between the magnetic field bump and the particle beam. These arrangements, when subjected to RF voltage, generate magnetic field flutter that mediates the interaction between the bump field and the beam, providing the necessary vertical focusing compensation without interfering with the orbit modification needed for extraction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If RF voltage sweep range is increased to compensate for magnetic field bowing, then particle acceleration coverage is improved, but system complexity increases

Engineering Contradiction:
Improveparticle acceleration coverageVSAvoidRF voltage control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system replaces the need for extensive RF voltage sweeping with a magnetic field-based solution. By introducing ferromagnetic arrangements that generate magnetic field flutter, the system substitutes mechanical/electrical adjustment (RF voltage sweep) with a magnetic field mechanism, thereby reducing RF control complexity while maintaining acceleration coverage.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of changing the RF voltage sweep range to accommodate magnetic field bowing, the system changes the magnetic field parameters by introducing ferromagnetic arrangements. This parameter change approach allows the system to maintain a fixed, simpler RF voltage regime while achieving the necessary particle acceleration through magnetic field modifications.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If ferromagnetic arrangements are added to provide magnetic field flutter, then vertical focusing is restored, but device complexity increases

Engineering Contradiction:
Improvevertical focusingVSAvoidmagnetic field structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The magnetic field control is segmented into distinct functional zones: the magnetic field bump region for orbit modification and the ferromagnetic arrangements region for vertical focusing. This segmentation allows each component to perform its specific function independently, reducing the overall system complexity by avoiding the need for a single complex system to handle both functions simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ferromagnetic arrangements serve multiple functions: they provide magnetic field flutter for vertical focusing, work in conjunction with the magnetic field bump for particle extraction, and can be positioned to optimize both functions simultaneously. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach enhances beam stability by maintaining vertical focusing, reduces the complexity and cost of RF voltage control, and allows for a more compact accelerator design by minimizing magnetic field bowing, thereby improving the overall efficiency of particle beam acceleration.

Implementation Method 1

a magnetic field having flux that bows at edges of the cavity

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

ferromagnetic arrangements located in the cavity proximate to the radius

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

A voltage source sweeps a radio frequency (RF) voltage in a cavity to accelerate particles from a plasma column

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP2901820B1Focusing a particle beam using magnetic field flutter
Publication Date: 2021.02.17 MEVION MEDICAL SYSTEMS INC
  • EP2901820B1 patent drawingFigure 1
  • EP2901820B1 patent drawingFigure 2
  • EP2901820B1 patent drawingFigure 3

AI summary

An example particle accelerator may include the following: a voltage source to sweep a radio frequency (RF) voltage in a cavity to accelerate particles from a plasma column, where the cavity has a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity, and where the magnetic field has flux that bows at edges of the cavity; a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to an extraction point, where the regenerator is located at a radius in the cavity relative to the plasma column; and ferromagnetic arrangements located in the cavity proximate to the radius, where each ferromagnetic arrangement provides a magnetic field bump, and where ferromagnetic arrangements adjacent to the regenerator are separated from the regenerator by a space.