Neutron Detector with Movable Solid-Liquid Moderators
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Solution Overview
Problem
Current neutron detectors with fixed moderator thicknesses are limited in measuring a wide range of neutron energies, leading to low sensitivity and inefficiency in capturing high-energy neutrons, and existing designs are often cumbersome, unsafe, or insufficient for applications requiring variable energy measurements.
Innovation Solution
A neutron detector with programmable or remotely controllable solid and liquid moderator layers, allowing variable thickness adjustments, enabling precise measurements across a wide energy range by using interchangeable polyethylene moderators and a tungsten sheath for gamma radiation protection, along with an electronic control unit for precise moderator movement and liquid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed thickness moderator layer is used, then the detector structure is simple, but the detector cannot measure neutrons across a wide energy range
Solution Approach 1:
The patent implements a movable moderator system where the moderator can be dynamically repositioned along the neutron beam path using a motorized mechanism. This allows the effective moderator thickness to be changed continuously or in discrete steps, enabling the detector to measure neutrons across a wide energy range (from thermal to high-energy neutrons) while maintaining a relatively simple overall structure.
2Reliability
If a thicker moderator layer is used, then high-energy neutrons can be slowed down effectively, but low-energy neutrons cannot pass through to reach the detector
Solution Approach 1:
The movable moderator allows dynamic adjustment of moderator thickness. For high-energy neutrons, the moderator is positioned to provide maximum thickness for effective slowing down. For low-energy or thermal neutrons, the moderator can be repositioned or removed entirely to allow these neutrons to reach the detector without being over-slowed or absorbed, thus covering a wide energy range while maintaining high capture efficiency for each energy type.
Solution Approach 2:
The system can periodically adjust the moderator position between measurements of different energy ranges. Between measurements, the moderator can be repositioned to optimize for the next energy range, allowing the detector to systematically cover the full energy spectrum through periodic reconfiguration.
3Reliability
If multiple detectors with different moderator thicknesses are used, then measurement sensitivity is improved, but the device becomes cumbersome and difficult to handle
Solution Approach 1:
Instead of using multiple separate detectors, the patent segments a single detector's capability by introducing a movable moderator that can create different effective thickness configurations. This segmentation of the neutron beam path allows one detector to perform the function of multiple detectors with different moderator thicknesses, maintaining high measurement sensitivity while preserving portability and ease of handling.
Solution Approach 2:
The movable moderator mechanism enables a single detector to perform multiple functions that would otherwise require multiple detectors. By adjusting the moderator position, the same detector can measure thermal neutrons, epithermal neutrons, and high-energy neutrons, making it a universal neutron detector for wide energy range measurements while remaining compact and portable.
4Adaptability or versatility
If manual moderator changes are required, then the detector can adapt to different energy ranges, but the measurement duration is extended and radiation safety is compromised
Solution Approach 1:
The motorized movable moderator eliminates manual intervention by automatically repositioning the moderator between measurements. This dynamic reconfiguration can occur quickly and remotely, allowing the detector to adapt to different energy ranges without extending measurement duration or requiring personnel to enter radiation areas, thus maintaining safety while enabling wide energy range coverage.
Solution Approach 2:
The system performs self-reconfiguration through automated control mechanisms. The moderator positioning system can be controlled remotely or through programming, allowing the detector to automatically adjust its configuration for different energy ranges without external manual intervention, reducing measurement time and eliminating the need for personnel exposure to radiation during moderator changes.
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 detector achieves high sensitivity and portability by allowing customizable moderator thickness, effectively capturing neutrons across a broad energy range while ensuring safety and efficiency in radiation environments.
Implementation Method 1
The primary aim of neutron detectors is reducing energy of neutrons received by the detector with the effect of scatterings
Implementation Method 2
a tungsten sheath for gamma radiation protection
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The neutron detector that allows the measurement of neutrons under different energies enable the solid and liquid moderators with changeable thicknesses to be used in the same design. The detector is simply comprised of a cylindrical solid moderator movement chamber (1), a detector measurement chamber (2) and a liquid moderator storage chamber (3), which are stacked on each other. The detector measurement chamber (2) is formed of a detector (4) at the center and a tungsten sheath (9) providing a shield to the detector by surrounding it, against gamma radiation. The solid moderator motion lever (5) is fixed to the solid moderators (7) and hence enables them to move in the vertical axis.