Pulsed Neutron Generator Tube Cylindrical Target
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Solution Overview
Problem
Conventional pulsed neutron generators for oil and gas well logging face limitations due to small diameter constraints, which restrict the radial size of components and ion beam current, leading to reduced neutron yield and efficiency.
Innovation Solution
A pulsed neutron generator tube with a field ionization array and a cylindrical target section using a deuterium-deuterium fusion reaction, incorporating nano-emitters and a multilayer target structure to enhance ion generation and increase target surface area, resulting in a higher neutron yield and improved operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the neutron generator tube is reduced to meet logging tool constraints, then the device can be deployed in narrow boreholes, but the radial size of components and ion beam current are restricted, leading to reduced neutron yield
Solution Approach 1:
The patent transitions from a conventional planar target configuration to a three-dimensional cylindrical target structure. The cylindrical target provides a significantly larger surface area for ion bombardment within the same radial space, effectively increasing the neutron production volume without expanding the outer diameter of the generator tube.
Solution Approach 2:
The patent employs a porous target structure that allows for increased surface area and improved heat dissipation. The porous configuration enables greater ion beam interaction volume while maintaining a compact external dimension, thereby increasing neutron yield within the constrained tube diameter.
2Productivity
If conventional Penning ion sources are used, then the ion source can operate with simple structure, but they produce mostly diatomic deuterium ions and shift between operation modes, reducing efficiency
Solution Approach 1:
The patent replaces the conventional Penning discharge ion source with a field ionization array. This substitution eliminates the need for complex magnetic field configurations and high voltage pulse circuits, while providing stable monatomic ion production. The field ionization mechanism uses electric field enhancement at sharp tips to directly ionize deuterium gas, achieving higher efficiency without mechanical or magnetic complexity.
Solution Approach 2:
The patent changes the ionization mechanism from thermal Penning discharge to electric field-based field ionization. This parameter change in the ionization process enables production of predominantly monatomic deuterium ions rather than diatomic ions, improving the efficiency of neutron production while simplifying the overall source structure.
3Reliability
If permanent magnets are used to provide magnetic field, then the structure is simple, but the magnetic properties degrade at high temperatures required for out-gassing
Solution Approach 1:
The patent extracts and removes the permanent magnet component from the system entirely. By eliminating the magnetic field requirement through adoption of field ionization, the design avoids the fundamental problem of magnetic property degradation at high temperatures. The out-gassing process can proceed at elevated temperatures without compromising magnetic field stability.
Solution Approach 2:
The patent converts the harmful effect of high temperature (which degrades permanent magnet properties) into a beneficial aspect by eliminating the magnet entirely. The high temperature required for out-gassing is now acceptable since it no longer affects magnetic components, and may even enhance the field ionization process by increasing gas pressure and ionization efficiency.
4Adaptability or versatility
If solenoid is used instead of permanent magnets, then magnetic field can be controlled, but two electrical connections and associated circuitry are required, increasing complexity
Solution Approach 1:
The patent removes the solenoid and all associated magnetic field control circuitry from the system. By adopting field ionization, the design eliminates the need for any magnetic field generation mechanism, thereby removing the requirement for additional electrical connections and control circuitry while maintaining operational versatility through electric field control.
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
The design achieves a neutron yield higher than 1e7 neutrons per second, overcoming the limitations of conventional systems by increasing the target surface area and reducing thermal desorption, while being power-efficient and suitable for logging applications.
Implementation Method 1
A pulsed neutron generator tube uses a field ionization array to produce over 50% monatomic deuterium ions
Implementation Method 2
deuterium-deuterium fusion reaction
Data Source
AI summary
Various embodiments include apparatus and methods of using the apparatus having a neutron generator. The neutron generator can include a neutron generator tube having a cylindrical inner surface that bounds a cylindrical cavity, a field ionization array cylindrically distributed on the cylindrical inner surface, and a target rod positioned in the cylindrical cavity. Additional apparatus, systems, and methods are disclosed.