Dose Rate Detector with Scintillation and Semiconductor Sensors
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Solution Overview
Problem
Existing dose rate measuring devices face challenges in achieving satisfactory output energy characteristics throughout the entire energy range and linearity in measurement, particularly due to stepped differences between switching points in low-range and high-range dose rate regions.
Innovation Solution
A dose rate measuring device is designed with a detection unit comprising a first radiation detector and multiple second radiation detectors, where the second detectors are positioned to ensure equal radiation incidence and sensitivity areas, allowing for energy compensation by determining an energy compensation factor based on average pulse height values from these detectors, which is then applied to the high-range dose rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple dose rate measuring devices are installed to measure a wide range of dose rates, then measurement coverage is improved, but device cost and mutual interference increase
Solution Approach 1:
The single detector is divided into multiple sensor units (first radiation detector and second radiation detector with three or more sensor units) that perform different functions. The first detector handles low-range dose rates using pulse height discrimination, while the second detector handles high-range dose rates using current measurement, enabling wide-range measurement without multiple separate devices
Solution Approach 2:
The single dose rate measuring device is designed to universally measure both low-range and high-range dose rates by incorporating multiple detection methods within one device. The system can automatically switch between DBM method for low-range and current measurement method for high-range, making one device perform the work of multiple specialized devices
2Manufacturing precision
If a lead shield is added to reduce stepped difference between switching points, then switching smoothness is improved, but output energy characteristics in low-range dose rate deteriorate
Solution Approach 1:
The switching point between low-range and high-range dose rate measurement is made dynamic rather than fixed. The system automatically determines the optimal switching point based on the measured dose rate level, allowing the switching threshold to adapt to different measurement conditions and energy levels, thereby avoiding the stepped difference problem without requiring a lead shield
Solution Approach 2:
The measurement parameters are changed based on the dose rate level. For low-range dose rates, pulse height discrimination with DBM method is used, while for high-range dose rates, current measurement method is used. This parameter change allows optimal measurement characteristics across different ranges without the need for physical modifications like lead shields
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 configuration ensures satisfactory energy characteristics and linearity across the entire measurement range, effectively reducing stepped differences between switching points, enabling accurate measurement of a wide range of dose rates.
Implementation Method 1
a thallium-activated sodium iodide scintillation detector is provided
Implementation Method 2
second radiation detector for detecting radiation in three or more sensor units and outputting analog voltage pulses
Data Source
AI summary
Three semiconductor detectors are installed at positions where incidence of radiation on a scintillation detector is not blocked, at equal intervals centered on a central axis of the scintillation detector and at equal angles with respect to a plane which is at a right angle to the central axis. An energy compensation factor is determined on the basis of an average pulse height value obtained from a second pulse height spectrum obtained by analog voltage pulses which are output from these semiconductor detectors, and energy characteristics of a high-range dose rate obtained by a direct-current voltage which is output from the scintillation detector are compensated for.