Radiation Generator Bipolar Electrodes Particle Capture
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Solution Overview
Problem
Neutron generators used in well logging instruments face issues with conductive particle buildup on insulating surfaces, altering the electric field and ion beam focus, and neutralization of ions leading to performance degradation and potential damage.
Innovation Solution
A radiation generator design with an insulator housing an ion source, an extractor electrode at a first potential, an intermediate electrode at ground potential to capture undesirable particles, and a suppressor electrode at a second potential opposite to the first, creating a shortened acceleration gap to reduce charge exchange reactions and secondary electron emission, while shaping electrodes to direct secondary electrons to ground and reduce x-ray generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ions are accelerated toward the target using conventional electrode arrangements, then neutron generation is achieved, but conductive particles build up on insulating surfaces altering the electric field and ion beam focus
Solution Approach 1:
A grounded intermediate electrode is introduced between the high voltage extractor electrode and the target. This intermediate electrode acts as a mediator that captures secondary electrons and conductive particles before they can reach the insulating surfaces, thereby preventing charge buildup while maintaining the acceleration field for ion beam generation
Solution Approach 2:
The acceleration gap is divided into multiple sections by introducing the intermediate electrode at ground potential. This segments the originally single acceleration region into distinct zones, allowing separate control of ion acceleration and secondary particle management, thus preventing conductive particle buildup on insulators
2Power
If ions are accelerated over a longer distance to achieve sufficient energy, then neutron generation efficiency improves, but the ion beam becomes less focused and strikes the wrong portion of the target
Solution Approach 1:
Different regions of the acceleration gap are given different electrical characteristics. The region near the ion source maintains high voltage gradient for focused beam extraction, while the region near the target uses grounded intermediate electrodes to maintain focus precision, allowing both high energy and precise focusing to be achieved simultaneously
3Device complexity
If conventional electrode configurations are used, then device simplicity is maintained, but performance degrades due to particle buildup and electric field alteration
Solution Approach 1:
The grounded intermediate electrode serves as a mediator that stabilizes the electric field by providing a reference potential between the high voltage extractor and the target. This simple addition prevents field distortion from charge buildup without requiring complex electrode geometries or control systems
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 design enhances the stability and consistency of the ion beam, reduces undesirable particle buildup, and minimizes performance degradation by maintaining a focused ion beam and reducing the risk of shorts and target erosion, thereby improving neutron generation and instrument reliability.
Implementation Method 1
the extractor electrode and the suppressor electrode may have a voltage therebetween such that an electric field generated in the insulator accelerates the ions generated by the ion source toward the target
Implementation Method 2
an intermediate electrode may be carried within the insulator downstream of the extractor electrode at a ground potential and may be shaped to capture the undesirable charged or conductive particles indirectly generated by the ion source
Data Source
AI summary
A radiation generator includes an insulator, with an ion source carried within the insulator and configured to generate ions and indirectly generate undesirable particles. An extractor electrode is carried within the insulator downstream of the ion source and has a first potential. An intermediate electrode is carried within the insulator downstream of the extractor electrode at a ground potential and is shaped to capture the undesirable conductive particles. In addition, a suppressor electrode is carried within the insulator downstream of the intermediate electrode and has a second potential opposite in sign to the first potential. A target is carried within the insulator downstream of the suppressor electrode. The extractor electrode and the suppressor electrode have a voltage therebetween such that an electric field generated in the insulator accelerates the ions generated by the ion source toward the target.