Synchrotron Accelerator with Eccentric Trajectories for Ion Beam Extraction

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Solution Overview

Problem

Current particle beam irradiation systems using synchrotrons struggle to reduce size while maintaining efficient ion beam extraction, and cyclotrons face limitations in adjusting ion beam energies for precise cancer treatment, leading to inefficiencies and increased radioactive waste.

Innovation Solution

The development of an accelerator with two facing iron cores and isochronous magnetic fields, featuring densely formed annular beam turning trajectories and a massless septum for efficient extraction of ion beams of different energies, allowing for continuous and precise energy adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a synchrotron is used to enable energy adjustment for precise cancer treatment, then manufacturing precision and adaptability are improved, but device complexity and size increase

Engineering Contradiction:
Improveenergy adjustment precisionVSAvoidaccelerator structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the ion source, linear accelerator, and synchrotron into an integrated accelerator system. The ion source is positioned at the center of the synchrotron ring, and the linear accelerator serves as both an injector and an energy adjustment mechanism, reducing the need for separate energy adjustment components while maintaining precise energy control for different treatment depths

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The linear accelerator performs multiple functions: it accelerates ions from the ion source, injects them into the synchrotron, and adjusts their energy before injection. This multi-functional design reduces device complexity while maintaining the ability to precisely control ion beam energy for treating tumors at different depths

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

2Device complexity

If a cyclotron is used to reduce accelerator size, then device complexity is reduced, but adaptability deteriorates due to inability to adjust ion beam energies

Engineering Contradiction:
Improveaccelerator structure simplicityVSAvoidion beam energy adjustment capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts ion beam energy by controlling the number of acceleration cycles in the linear accelerator before injection into the synchrotron. The radiofrequency voltage frequency and amplitude are dynamically adjusted to achieve precise energy control, enabling the compact accelerator to treat tumors at various depths adaptably

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key operational parameters including radiofrequency voltage frequency, amplitude, and phase to control ion beam energy. By adjusting these parameters, the system can deliver ions at different energies to treat tumors at different depths, providing the adaptability normally associated with larger accelerator systems

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple metal plates are used in cyclotron beam transport to adjust ion beam energy, then energy adjustment is achieved, but loss of substance increases due to radioactive waste

Engineering Contradiction:
Improveion beam energy adjustmentVSAvoidradioactive waste generation
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical degrader system (multiple metal plates) with a radiofrequency-based energy adjustment mechanism. The linear accelerator uses electromagnetic fields to adjust ion beam energy through controlled acceleration cycles, eliminating the need for physical metal plates and the associated radioactive waste generation

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

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 configuration enables efficient extraction of ion beams of varying energies, reducing the size of the accelerator and minimizing radioactive waste, while enabling precise energy control for effective cancer treatment.

Implementation Method 1

The ion beam turning through the beam duct is accelerated to a predetermined energy in the radiofrequency acceleration cavity to which a radiofrequency voltage is applied

Methodology Applied
Scientific EffectRadiofrequency acceleration: Electromagnetic Induction

Implementation Method 2

The synchrotron includes an annular beam duct, and the beam duct is provided with multiple bending magnets

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

The beam duct is provided with multiple bending magnets, multiple quadrupole magnets

Methodology Applied
Scientific EffectMagnetic field focusing: Magnetic Field

Implementation Method 4

Ions (for example, protons or carbon ions) extracted from the ion source

Methodology Applied
Scientific EffectIonization: Ionisation

Data Source

PatentEP3232742B1Accelerator and particle beam radiation device
Publication Date: 2020.11.18 HITACHI LTD
  • EP3232742B1 patent drawingFigure 1
  • EP3232742B1 patent drawingFigure 2
  • EP3232742B1 patent drawingFigure 3

AI summary

To provide an accelerator which is capable of efficiently extracting ion beams of different energies. The accelerator includes a circular vacuum container including a pair of circular return yokes facing each other. An injection electrode 18 is disposed closer to an inlet of a beam extraction path in the return yoke than a central axis of the vacuum container. Six magnetic poles are radially disposed from the injection electrode 18 at the periphery of the injection electrode 18 in the return yoke. Six recessions are disposed alternately with the respective magnetic poles in the circumferential direction of the return yoke. In the vacuum container, a concentric trajectory region, in which multiple beam turning trajectories 78 centered around the injection electrode 18 are present, is formed, and an eccentric trajectory region, in which multiple beam turning trajectories eccentric from the injection electrode 18 are present, is formed around the region. In the eccentric trajectory region, the beam turning trajectories 78 are dense between the injection electrode 18 and the inlet of the beam extraction path. Gaps between the beam turning trajectories 78 are wide in a direction 180° opposite to the inlet of the beam extraction path relative to the injection electrode 18.