Accelerator Cavities With Multipole Convergence for High-Intensity Beams

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Solution Overview

Problem

Conventional RFQ accelerators face limitations in increasing beam intensity due to discharge power limits and beam diameter constraints, necessitating a larger apparatus size and cost, while requiring a different type of accelerator for high-intensity beams.

Innovation Solution

An accelerator system with individually controllable acceleration cavities and multipole magnets to control beam motion, allowing for reduced intergap spacing and increased bore diameter, using a magnetic field for convergence instead of an electric field to manage beam diameter and intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the bore diameter of the RFQ accelerator is increased to accommodate larger beam diameter for higher intensity, then the beam intensity can be increased, but the discharge power limit is reached

Engineering Contradiction:
Improvebeam intensityVSAvoiddischarge power
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent replaces the electric field-based convergence system of conventional RFQ accelerators with a magnetic field-based convergence system using multipole magnets. This substitution allows the bore diameter to be increased beyond the discharge power limit of electric field systems, enabling accommodation of larger beam diameters (10 cm or more) while maintaining beam convergence and achieving higher beam intensities of 1 A or more without exceeding discharge power limits.

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

2Speed

If the intergap spacing is increased to accommodate higher beam velocity, then the beam can be accelerated more effectively, but the apparatus size and cost increase

Engineering Contradiction:
Improvebeam velocityVSAvoidapparatus length
Core Design Contradiction:
SpeedVSLength of stationary object

Solution Approach 1:

The patent employs individually controllable acceleration cavities with independently adjustable radiofrequency voltages and phases. This dynamic control capability allows optimization of intergap spacing for different beam velocities, enabling effective acceleration of high-velocity beams while maintaining compact apparatus dimensions by preventing excessive intergap spacing.

Inventive Principle:
Principle #15Dynamics

3Productivity

If conventional RFQ accelerator is used for high-intensity beams, then the existing technology can be utilized, but sufficient acceptance with respect to beam diameter cannot be secured

Engineering Contradiction:
Improvebeam intensityVSAvoidbeam diameter acceptance
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent fundamentally changes the convergence mechanism parameter from electric field to magnetic field, enabling the bore diameter to be increased to 10 cm or more. This parameter change provides sufficient acceptance for large beam diameters required by high-intensity beams of 1 A or more, while maintaining beam convergence through multipole magnets.

Inventive Principle:
Principle #35Parameter changes

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

Enables the production of high-intensity beams with reduced cost and apparatus length, capable of handling beam currents up to 1 A without exceeding discharge power limits, and maintaining efficient radiofrequency power usage.

Implementation Method 1

An oscillating electric field is independently controlled in each acceleration cavity

Methodology Applied
Scientific EffectOscillating electric field: Electric Field

Implementation Method 2

acceleration, convergence, and adiabatic capture (bunching) of beams can be simultaneously performed

Methodology Applied
Scientific EffectRadiofrequency power: Electromagnetic Induction

Implementation Method 3

a second control means which generates a magnetic field and controls a motion of the ion beam

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3745826B1Accelerator and accelerator system
Publication Date: 2025.10.22 RIKEN CO LTD
  • EP3745826B1 patent drawingFigure 1
  • EP3745826B1 patent drawingFigure 2
  • EP3745826B1 patent drawingFigure 3(A)~3(B)

AI summary

An accelerator (30, 40, 50) includes: a plurality of acceleration cavities (31, 41, 51) having one or two acceleration gaps; and a plurality of first control means (33, 43, 53) provided with respect to each of the plurality of acceleration cavities, each of the plurality of first control means independently generating an oscillating electric field and controlling a motion of an ion beam inside a corresponding acceleration cavity. In addition, M-number of multipole magnets (32, 42, 52) which generate a magnetic field and which control a motion of an ion beam may be provided downstream to N-number of acceleration cavities. The first control means independently controls acceleration voltage and a phase thereof and supplies radiofrequency power. Accordingly, particularly in a front stage of acceleration, a DC beam from an ion generation source can be adiabatically captured.