Rod-Shaped Survey Meter for Small Pipe Contamination Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional surface contamination survey meters are inefficient in measuring radioactive contamination on the inner surfaces of pipes and tubes with small diameters due to physical configuration and size limitations, leading to attenuated radiation detection and high manufacturing costs.
Innovation Solution
A survey meter with a rod-shaped light guide unit, a scintillator unit on the circumferential surface, and a shielding member to improve light conversion properties, allowing for efficient detection of radioactive contamination in small diameter pipes and tubes with a low-cost, compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat plate-shaped radiation detecting unit is used, then the structure is simple and easy to manufacture, but the detecting efficiency is low when measuring inner surface contamination of pipes due to unavoidable gap distance
Solution Approach 1:
The radiation detecting unit is changed from a flat plate shape to a rod shape with a curved surface. This curved surface can be brought into direct contact with the inner surface of pipes, eliminating the gap distance problem and improving detecting efficiency for low energy α-rays and β-rays while maintaining ease of manufacture.
2Adaptability or versatility
If the radiation detecting unit is made smaller to fit small diameter pipes, then the adaptability to small pipes is improved, but the detecting capability is reduced due to smaller detection area
Solution Approach 1:
The radiation detecting unit is designed as a rod shape that can be inserted into the pipe along the axial direction. This allows the detection surface to extend in the axial dimension rather than being limited by the radial dimension, enabling the use of small diameter pipes while maintaining sufficient detection area and capability.
3Ease of operation
If a wavelength conversion optical fiber is used to transmit signals, then the distance between radiation detecting unit and measuring unit can be increased, but the light transmission loss due to self-absorption reduces detecting efficiency
Solution Approach 1:
The wavelength conversion optical fiber is removed from the system. Instead, a transparent optical fiber is used to transmit the fluorescent light directly from the scintillator to the photo-multiplier tube, eliminating the light transmission loss caused by self-absorption in wavelength conversion fibers while still allowing flexible distance arrangement.
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 solution enhances detection sensitivity and efficiency while reducing manufacturing costs and handling difficulties, enabling effective measurement of radioactive contamination on inner surfaces of small diameter pipes and tubes.
Implementation Method 1
a scintillator unit (2) for emitting a fluorescent light generated by the radioactive ray irradiated from a surface of a measuring object (object to be measured) (16)
Implementation Method 2
a photoelectric transfer unit (3) for converting the fluorescent light into an electric signal
Data Source
AI summary
A survey meter for measuring a radioactive contamination caused in an inner surface of a pipe includes a radiation detecting section and a signal processing section. The radiation detecting section includes a rod-shaped light guide unit, a reflecting portion connected to one end surface of the light guide unit, a photoelectric transfer unit, for outputting an electronic signal, connected to another one end surface of the light guide unit, and a scintillator unit provided to a circumference of the light guide unit. The signal processing section includes a pulse height discriminator for outputting a logic signal at a time when a pulse height value of the electronic signal outputted from the photoelectric transfer unit is higher than a threshold value, a counter unit for counting the logic signal, a contamination judging unit for judging whether a radioactive contamination is caused or not, and a display unit for displaying the value counted by the counter unit and a contamination judging result judged by the contamination judging unit.