Scanning Electromagnet Control for Fast Charged-Particle Deflection

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Solution Overview

Problem

Existing scanning electromagnets in particle beam therapy systems face issues with scanning speed due to counter electromotive forces generated by inductance of coils when changing irradiation positions, leading to prolonged scanning times and increased patient burden.

Innovation Solution

A scanning electromagnet control system that applies constant voltages when the charged particle beam direction is fixed and varying voltages with increased potential differences when the direction changes, optimizing the scanning process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If excitation current is changed when irradiation position is changed, then the charged particle beam can be deflected to new positions, but counter electromotive force generated by coil inductance decreases scanning speed and prolongs treatment time

Engineering Contradiction:
Improvescanning speedVSAvoidtreatment time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The control unit calculates and sets the voltage to be applied to each terminal in advance before changing the irradiation position. By pre-calculating the required voltage based on the target irradiation position and the excitation current characteristics, the system prepares the optimal voltage profile that accounts for counter electromotive force effects, enabling faster and more accurate beam deflection without treatment time extension

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the voltage applied to each terminal based on the changing irradiation position and beam energy. By changing the voltage parameters in real-time according to the required excitation current and counter electromotive force conditions, the system optimizes scanning speed while maintaining precise beam control throughout the treatment process

Inventive Principle:
Principle #35Parameter changes

2Reliability

If appropriate voltage is not applied to compensate for counter electromotive force, then the scanning electromagnet cannot overcome inductance effects, but applying insufficient voltage causes the charged particle beam to deviate from desired orbit

Engineering Contradiction:
Improvebeam orbit accuracyVSAvoidscanning speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The control unit determines the voltage to be applied based on the relationship between the target irradiation position, beam energy, and excitation current characteristics. This feedback mechanism ensures that the applied voltage compensates for counter electromotive force effects while maintaining the charged particle beam on the desired orbit, achieving both high scanning speed and orbital accuracy

Inventive Principle:
Principle #23Feedback

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

Enhances scanning speed and efficiency of charged particle beams, reducing treatment time and improving patient throughput.

Implementation Method 1

a scanning electromagnet that causes magnetic fields generated by a plurality of systems of windings whose one ends are connected to each other to act on a charged particle beam to deflect the charged particle beam

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 2

by generating a magnetic field in a direction crossing the charged particle beam to deflect the charged particle beam

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

Since the excitation current is changed when the irradiation position is changed, a counter electromotive force caused by an inductance of a coil is generated

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4629263A1Scanning electromagnet control system, scanning electromagnet control method, and particle therapy system
Publication Date: 2025.10.08 HITACHI HIGH TECH CORP
  • EP4629263A1 patent drawingFigure 1
  • EP4629263A1 patent drawingFigure 2~3
  • EP4629263A1 patent drawingFigure 4~5

AI summary

Provided is a scanning electromagnet control system capable of scanning a charged particle beam at a higher speed. A scanning electromagnet (1) deflects a charged particle beam by causing magnetic fields generated by a plurality of systems of windings (U), (V), and (W) whose terminating ends are connected to each other to act on the charged particle beam. A scanning electromagnet control system (2) applies a constant voltage to each of starting ends of the windings (U), (V), and (W) of the scanning electromagnet (1) when a direction of the charged particle beam is fixed, the constant voltage corresponding to the direction of the charged particle beam, and applies a varying voltage to each of the starting ends of the windings (U), (V), and (W) when the direction of the charged particle beam is changed, the varying voltage causing a potential difference between the starting ends of the windings (U), (V), and (W) to be larger than potential differences before and after the change of the direction.