Linac Arcing Detection Using Reflected RF Power Signals

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Solution Overview

Problem

Arcing events in radiotherapy linear accelerators (linacs) are common and can lead to downtime and component damage, necessitating improved detection methods that do not require additional monitoring equipment or personnel.

Innovation Solution

A method for detecting arcing events within linacs by analyzing reflected radiofrequency (RF) power signals using components of the linac, such as a discriminator and beam generation controller, to automatically identify anomalies indicative of arcing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual monitoring with oscilloscope is used, then arcing events can be detected, but additional equipment and skilled personnel are required

Engineering Contradiction:
Improvearcing detection capabilityVSAvoidmonitoring equipment requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The linac system monitors its own reflected RF power signals using existing internal components (discriminator, beam generation controller) without requiring external monitoring equipment. The system serves itself by utilizing its operational signals for self-diagnosis of arcing events.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Existing linac components (discriminator and beam generation controller) are made multi-functional by enabling them to perform both their original functions and arcing detection. The reflected RF power signal, originally used for beam generation control, is now also used for detecting arcing events.

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

2Reliability

If manual monitoring by skilled engineer is used, then arcing events can be identified, but the process is subjective and requires personnel

Engineering Contradiction:
Improvearcing event identificationVSAvoidoperational simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system automatically detects and flags arcing events using its own components and signals, eliminating the need for skilled engineers to manually monitor and interpret oscilloscope readings. The beam generation controller autonomously performs the detection function.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback from the reflected RF power signal to automatically detect arcing events. The discriminator provides continuous feedback about signal anomalies, enabling automatic identification of arcing without human intervention.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If additional monitoring equipment is used, then detection capability is improved, but system complexity and cost increase

Engineering Contradiction:
Improvearcing detection precisionVSAvoidequipment quantity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The linac system uses its own existing components (discriminator, beam generation controller) and operational signals (reflected RF power) to detect arcing events, eliminating the need for separate monitoring equipment like oscilloscopes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The discriminator and beam generation controller are made multi-functional, serving both beam generation control and arcing detection purposes, thereby eliminating the need for dedicated monitoring equipment.

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

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 automatic and objective detection of arcing events without the need for additional equipment or personnel, improving linac reliability and reducing downtime.

Implementation Method 1

obtaining a reflected radiofrequency, RF, power signal

Methodology Applied
Scientific EffectRadiofrequency reflection: Reflection

Data Source

PatentEP4672869A1Detecting arcing events within a linear accelerator
Publication Date: 2025.12.31 ELEKTA AB
  • EP4672869A1 patent drawingFigure 1
  • EP4672869A1 patent drawingFigure 2
  • EP4672869A1 patent drawingFigure 3

AI summary

Methods and systems for detecting arcing events within linear accelerators are disclosed herein. Arcing is detected within a linear accelerator using a reflected RF power signal. Such methods can be performed automatically using components of the linear accelerator itself. The method comprises obtaining a reflected RF power signal, detecting an anomaly based on the reflected RF power signal, the anomaly being indicative of the occurrence of an arcing event, and outputting a signal indicating an arcing event has occurred.