Electronic Switches for Multi-Energy LINAC Interleaving

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Solution Overview

Problem

Standing wave linear accelerators face challenges in generating x-rays of multiple energy bands efficiently due to limited modes of operation, leading to overheating issues with electronic switches during fast-switching operations.

Innovation Solution

The implementation of detunable side cavities with electronic switches that are activated simultaneously to share microwave power losses equally, reducing heating and allowing for controlled energy switching by modifying the reactance of the side cavities to adjust the electromagnetic wave propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If electronic switches are used for fast-switching operation to generate x-rays of multiple energy bands, then switching speed and lifetime are improved, but heating of the electronic switches increases

Engineering Contradiction:
Improveswitching speedVSAvoidheating of electronic switches
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The patent divides the single electronic switch into multiple electronic switches positioned at different locations within the accelerating structure. By segmenting the power loss absorption across multiple switches, the heating burden on each individual switch is reduced while maintaining the fast-switching capability needed for multi-energy band operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs asymmetric positioning of electronic switches at specific locations within the accelerating structure where electromagnetic fields have particular characteristics. This asymmetric placement optimizes the distribution of power losses and heating effects, allowing faster switching operation with reduced thermal burden on each switch.

Inventive Principle:
Principle #4Asymmetry

2Adaptability or versatility

If a standing wave LINAC is configured to support multiple modes for different electron energies, then energy versatility is improved, but stable operation at high dose rates for different energies becomes difficult

Engineering Contradiction:
Improveenergy versatilityVSAvoidstable operation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent makes the accelerating structure dynamically adjustable by incorporating electronic switches that can be activated or deactivated to change the resonant frequency and mode of operation. This dynamic reconfiguration allows the LINAC to stably operate at different energy levels and dose rates by electronically adjusting the accelerating fields rather than requiring physical reconfiguration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the accelerating structure by using electronic switches to modify the resonant frequency and field distribution. By electronically adjusting these parameters, the LINAC can stably generate electron beams at different energies and dose rates, improving both energy versatility and operational stability.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If mechanical energy switches are used with frequent activation for interleaved energy operation, then energy switching capability is improved, but switch lifetime is reduced due to high activation frequency

Engineering Contradiction:
Improveenergy switching capabilityVSAvoidswitch lifetime
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces mechanical energy switches with electronic switches that have no moving parts. This substitution eliminates mechanical wear and significantly extends switch lifetime while maintaining the capability for frequent energy switching. The electronic switches can be activated and deactivated rapidly without the mechanical degradation that limits the lifespan of plunger-type mechanical switches.

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 approach enables low heating of electronic switches during fast-switching operations, extending their lifespan and allowing for stable generation of electron beams at different energies, improving the efficiency and reliability of the standing wave linear accelerator.

Implementation Method 1

a device coupled to the element to control a resonant frequency of the side cavity

Methodology Applied
Scientific EffectResonant frequency control: Resonance

Implementation Method 2

a first set of electrons is accelerated in said longitudinal passageway by a standing electromagnetic wave coupled into said accelerator

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 3

Activating, substantially simultaneously as one another, said first and second electronic switches of said first and second detunable side cavities to a second activation state that is different from the first activation state and in which the first and second detunable side cavities dissipate an approximately equal amount of power as one another

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

a first set of electrons is accelerated in said longitudinal passageway by a standing electromagnetic wave coupled into said accelerator

Methodology Applied
Scientific EffectElectromagnetic acceleration: Electromagnetic Induction

Data Source

PatentEP2452545B1Interleaving multi-energy x-ray energy operation of a standing wave linear accelerator using electronic switches
Publication Date: 2018.08.22 ACCURAY INC
  • EP2452545B1 patent drawingFigure 1
  • EP2452545B1 patent drawingFigure 2A~2B
  • EP2452545B1 patent drawingFigure 3

AI summary

The disclosure relates to systems and methods for fast-switching operating of a standing wave linear accelerator (LINAC) for use in generating x-rays of at least two different energy ranges with advantageously low heating of electronic switches. In certain embodiments, the heating of electronic switches during a fast-switching operation of the LINAC can be kept advantageously low through the controlled, timed activation of multiple electronic switches located in respective side cavities of the standing wave LINAC, or through the use of a modified a side cavity that includes an electronic switch.