Drift Tube Linear Accelerator Phase Control for Ion Injection

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Solution Overview

Problem

Conventional synchrotron injector systems are inefficient and large in size due to their inability to optimize energy levels for different kinds of ions, such as protons and carbon ions, leading to suboptimal acceleration and increased size requirements for accommodating varying charge-to-mass ratios.

Innovation Solution

A compact synchrotron injector system is designed with a drift tube linear accelerator that adjusts the phase difference of radio frequency electric fields to optimize energy levels for each type of ion, allowing high charge-to-mass ratio ions like protons to be accelerated with higher energy and low charge-to-mass ratio ions like carbon ions to be accelerated with lower energy, using a single accelerator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the same energy level is used for pre-accelerating different kinds of ions, then the synchrotron injector system can accommodate multiple ion types, but the system becomes large in size and inefficient

Engineering Contradiction:
Improveability to accelerate different kinds of ionsVSAvoidsize of accelerator
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent applies dynamics by making the phase difference between adjacent drift tubes adjustable rather than fixed. The phase difference is dynamically changed based on the charge-to-mass ratio of the ions being accelerated, allowing the same accelerator structure to optimize for different ion types without physical modification. This resolves the contradiction by enabling versatility through dynamic parameter adjustment rather than requiring multiple fixed-energy accelerators.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the phase difference parameter in the radio frequency electric field according to the charge-to-mass ratio of different ions. By adjusting this parameter, the accelerator can optimize the energy gain for each ion type, allowing high charge-to-mass ratio ions to receive higher energy and low charge-to-mass ratio ions to receive lower energy, thus reducing the overall system size while maintaining adaptability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If higher energy is used for high charge-to-mass ratio ions, then space charge effect is reduced, but the accelerator size increases to accommodate low charge-to-mass ratio ions

Engineering Contradiction:
Improvereduction of space charge effectVSAvoidsize of accelerator
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies local quality by providing different phase differences (and thus different energy gains) to different ion types within the same accelerator structure. High charge-to-mass ratio ions receive a larger phase difference and higher energy to reduce space charge effects, while low charge-to-mass ratio ions receive a smaller phase difference and lower energy. This localized optimization for each ion type resolves the contradiction between reducing space charge effects and maintaining compact size.

Inventive Principle:
Principle #3Local quality

3Volume of stationary object

If the accelerator is designed for optimal energy for low charge-to-mass ratio ions, then the accelerator size is reduced, but high charge-to-mass ratio ions cannot be accelerated effectively

Engineering Contradiction:
Improvesize of acceleratorVSAvoidacceleration efficiency for high charge-to-mass ratio ions
Core Design Contradiction:
Volume of stationary objectVSProductivity

Solution Approach 1:

The patent uses dynamics by making the phase difference adjustable based on the ion type. When accelerating high charge-to-mass ratio ions, the phase difference is increased to provide optimal energy for effective acceleration. When accelerating low charge-to-mass ratio ions, the phase difference is decreased to maintain compact size. This dynamic adjustment resolves the contradiction between accelerator size and acceleration efficiency for different ion types.

Inventive Principle:
Principle #15Dynamics

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 enables the efficient and compact injection of different ions into a synchrotron with optimal energy levels, reducing the need for large power generators and preventing beam divergence, thus enhancing the system's performance and size efficiency.

Implementation Method 1

a drift tube linear accelerator (5) including a plurality of drift tubes (T) arranged inside a cylindrical resonator (6) in a cylindrical axial direction; and a radio frequency generator (50) for feeding radio frequency power into the cylindrical resonator (6)

Methodology Applied
Scientific EffectRadio frequency electric field acceleration: Electromagnetic Induction

Implementation Method 2

Since high charge-to-mass ratio (charge/mass) ions (for example, the protons: charge/mass = 1/1) are largely subject to space charge effect, the energy for injecting the high charge-to-mass ions into a synchrotron is desired to be larger than that for injecting a low charge-to-mass ratio ions

Methodology Applied
Scientific EffectSpace charge effect: Coulomb's Law

Data Source

PatentEP3264868B1Injector system for synchrotron and operation method for drift tube linear accelerator
Publication Date: 2020.06.24 MITSUBISHI ELECTRIC CORP
  • EP3264868B1 patent drawingFigure 1
  • EP3264868B1 patent drawingFigure 2
  • EP3264868B1 patent drawingFigure 3

AI summary

When accelerating first ions, radio frequency power is fed to a drift tube linear accelerator so that the phase difference between an accelerating half cycle for accelerating the first ions in one of the plurality of drift tube gaps and the accelerating half cycle for accelerating the accelerated first ions reaching the next drift tube gap is set to a first accelerating cycle phase difference; and when accelerating second ions having a charge-to-mass ratio lower than the first ions, the radio frequency power is fed to the drift tube linear accelerator so that the phase difference between an accelerating half cycle for accelerating the second ions in the one drift tube gap and the accelerating half cycle for the accelerated second ions reaching the next drift tube gap is set to a second accelerating cycle phase difference that is larger than the first accelerating cycle phase difference.