Circular Accelerator Electrodes for Multi-Orbit Beam Position Detection

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Solution Overview

Problem

Existing circular accelerators, such as synchrocyclotrons and eccentric orbital accelerators, struggle to efficiently detect the position of charged particle beams with varying orbits of different radii of curvature, as they lack means to synchronize the RF electric field with the betatron oscillation frequency, and existing beam position monitors are ineffective for multiple orbits.

Innovation Solution

A circular accelerator equipped with a beam position monitor that applies a first radio frequency voltage to charged particle beams, incorporating electrodes that apply radio frequency and detect the beam position, allowing for synchronization of the RF electric field with the betatron oscillation frequency, thereby facilitating the detection of beams across different orbits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a beam position monitor is provided to detect charged particle beam positions, then measurement capability is improved, but device complexity increases due to additional electrodes and signal processing systems

Engineering Contradiction:
Improvebeam position detection capabilityVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The beam position monitor electrodes are merged with the existing acceleration electrodes. The same electrodes that apply RF voltage for acceleration also serve as position detection electrodes, eliminating the need for separate monitoring electrodes and reducing overall device complexity while maintaining measurement capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrodes are designed to perform multiple functions: they serve both as acceleration electrodes that apply RF voltage to the beam and as position monitor electrodes that detect beam position through capacitance changes. This multi-functionality reduces the total number of components needed in the system

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

2Adaptability or versatility

If existing beam position monitors are used with fixed electrode configurations, then device simplicity is maintained, but they cannot detect positions of beams with different orbit radii

Engineering Contradiction:
Improvemulti-orbit detection capabilityVSAvoidposition detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system uses dynamic RF voltage application to the electrodes, where the RF voltage frequency and phase are adjusted according to the betatron oscillation frequency of the beam. This dynamic adjustment allows the same fixed electrode configuration to accurately detect beam positions across multiple orbits with different radii

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the RF voltage parameters (frequency and phase) applied to the electrodes based on the detected betatron oscillation characteristics. By adjusting these parameters, the electrodes can effectively monitor beam positions for different orbit radii without requiring physical reconfiguration

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If RF voltage is applied to electrodes for acceleration, then beam acceleration is achieved, but beam position detection becomes difficult due to interference from the strong RF field

Engineering Contradiction:
Improveposition detection accuracyVSAvoidRF field interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses the RF field itself as an intermediary for detection. The electrodes measure capacitance changes caused by the beam's effect on the RF field distribution, rather than trying to measure beam position directly in the presence of the RF field. This indirect measurement approach allows position detection without direct interference from the strong RF field

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses the existing RF acceleration field to enable position detection. The same RF voltage applied for acceleration creates the electric field environment that allows capacitance-based position sensing, turning the potentially harmful RF interference into a useful detection mechanism

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

The solution enables the detection of charged particle beam positions in real-time, allowing for non-destructive measurement during operation.

Implementation Method 1

a circular accelerator that applies a first radio frequency voltage to a circulating charged particle beam to accelerate the charged particle beam

Methodology Applied
Scientific EffectElectromagnetic acceleration: Electromagnetic Induction

Implementation Method 2

When the beam passes through between the electrode plates, the charge amount of the electrode plates changes. The position of the beam can be acquired by signal processing the change in the charge amount as the change in the voltage value

Methodology Applied
Scientific EffectElectrostatic induction: Electrostatic Induction

Implementation Method 3

the RF electric field of the radio frequency kicker is adjusted to the betatron oscillation frequency of the charged particle beam, and the charged particle beam is moved out of the orbit using the resonance phenomenon

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4661600A1Circular accelerator and particle beam therapy system having circular accelerator
Publication Date: 2025.12.10 HITACHI HIGH TECH CORP
  • EP4661600A1 patent drawingFigure 1
  • EP4661600A1 patent drawingFigure 2
  • EP4661600A1 patent drawingFigure 3

AI summary

To provide a circular accelerator capable of detecting the position of a circulating charged particle beam and a particle beam therapy system including the circular accelerator. A circular accelerator (39) configured to apply a first radio frequency to a circling charged particle beam to accelerate the charged particle beam, the circular accelerator including: an electrode (12), (13) configured to apply the first radio frequency to the charged particle beam; and a beam position monitor (16) provided in the electrode and configured to detect a position of the charged particle beam.