Electron Gun Intermediate Electrode Integrity Testing
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Solution Overview
Problem
Conventional triode electron guns in radiotherapy systems can deliver uncontrolled radiation doses to patients if the connection to the intermediate electrode fails, leading to a significant increase in electron flow during therapy, potentially by a factor of 300.
Innovation Solution
Incorporating a controller that tests the integrity of the intermediate electrode by measuring current or applying a small alternating voltage to ensure it is functioning correctly, and deactivating the electron source if the electrode is found to be disconnected, thereby preventing uncontrolled radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional triode electron gun is used with an intermediate electrode to control electron flow, then the electron flow can be controlled during operation, but if the connection to the intermediate electrode fails, the electron flow becomes uncontrolled and delivers massive radiation doses to the patient
Solution Approach 1:
The patent implements preliminary testing of the intermediate electrode connection integrity before the electron source is activated. The controller applies a test voltage or current to verify the connection is intact, and only permits operation if the test passes. This prevents uncontrolled electron flow from occurring in the first place, resolving the safety issue without requiring continuous complex monitoring during operation.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors the integrity of the intermediate electrode connection and automatically deactivates the electron source if a failure is detected. This closed-loop control ensures that any connection failure immediately results in shutdown, preventing massive radiation doses while maintaining simple operation during normal use.
2Reliability
If the intermediate electrode connection is tested continuously to ensure safety, then patient safety is maximized, but the device complexity and operational interruptions increase
Solution Approach 1:
The patent performs connection integrity testing only before the electron source is activated or before treatment sessions begin, rather than continuously during operation. This preliminary check ensures safety is verified when it matters most, while avoiding operational interruptions during actual treatment delivery.
Solution Approach 2:
The system automatically manages the safety testing and activation sequence without requiring manual intervention. The controller autonomously performs integrity tests, determines whether conditions are safe for operation, and controls activation accordingly, simplifying the operator's role while maintaining high safety standards.
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
Ensures patient safety by preventing massive radiation doses during electron therapy by detecting and addressing potential failures in the intermediate electrode connection, allowing for controlled and safe operation of the electron source and linear accelerator.
Implementation Method 1
tests the integrity of the intermediate electrode by measuring current or applying a small alternating voltage
Implementation Method 2
electrons are liberated from the cathode, and accelerated towards the anode
Implementation Method 3
The grid is charged to an electric potential which has a retarding (and therefore controlling) effect on the electrons
Data Source
AI summary
The present invention provides an electron gun (12) comprising a cathode (20), for generating electrons; an anode (22); an intermediate electrode (24), located between the cathode and the anode; and a controller (14). The controller applies an electrical potential to said intermediate electrode, analysing a resultant electrical parameter to determine the integrity of said intermediate electrode; and controls the electron gun to emit a pulse of electrons.