Alpha-Radiometer with Surface Contamination Visualisation
Development of the Portable Alpha-Radiometer with a Silicon position-Sensitive Detector and with Visualisation of a Density Distribution of Alpha-Active Nuclides on an Inspected Surface
Tech Area / Field
- INS-DET/Detection Devices/Instrumentation
3 Approved without Funding
VNIIEF, Russia, N. Novgorod reg., Sarov
- NIIEFA Efremov, Russia, St Petersburg
Project summaryThe objective of the Project is the development of a laboratory model for a high-sensitive portable semiconductive -radiometer capable of providing visual quantitative information on the level of contamination, composition of alpha-nuclides and on their distribution over the surface of the item under control.
At present domestic and foreign industries produce a-radiometers with sensitive elements based on scintillation and gas-filled detectors. These devices have rather high metrological characteristics, their design is well developed but nevertheless they have some drawbacks associated with a type of the employed detector.
Efficiency of a-particle recording for radiometers with a scintillation detector is no more than 30%. Photomultiplier tubes and light guids to the mass and dimensions of radiometers and makes their operation more complicated.
Radiometers with a gas-filled detector offer higher recording efficiency (over 70%), but to keep the detector characteristics stable, it should be periodically blown through with a "fresh" mixed gas supplied from a special container, that adds to the mass and dimensions of the device and makes it operation more complicated, especially at low temperature.
Under real operating conditions detectors of both types have higher mechanical vulnerability. The reason is that their design must necessarily contain very thin (about several micrometers) light- or gas-impermeable film covering the working surface of detector. In the course of measurements this protective film may be damaged and the detector will fail to operate.
Besides, in the area of contaminated surfaces control there are some problems which can not be solved using available a-radiometers, namely: localization and determining the shape of a contamination spot, control over curved surfaces, qualitative estimate of nuclides composition for a-radiators immediately during measurements.
In a-radiometer developed under the Project the above-mentioned drawbacks will be eliminated through the use of up-to-date technologies of semiconductive instrument engineering for the development of a high-sensitive silicon detector and complex optimization of its characteristics.
The device will be equiped with a visualization unit to display information on localization of radio contamination spots, their shape, activity and nuclide composition of a-radiators.
Detection unit will have a special design which enables measurement of curved surfaces.
The working surface of the detector is mechanically stable and allows contact with solid and liquid media, besides it is easy to decontaminate.
Scope of activities:
· to conduct theoretical and experimental research aimed at the development and multiple-factor optimization of multicomponent silicon detector for recording nuclide a-radiation from a contaminated surface;
· to develop planar technology for manufacturing detecting elements with the sensitivity close to the ultimate possible value predicted by the theory;
· to develop a portable measuring system for recording a-radiation, mathematical processing and visualization of data on the contamination level and -nuclide composition at the controlled surface.
The final result of the Project will be: laboratory models of a-radiometer, test and calibration benches, scientific and technical documentation on the creation of a new generation of industrial prototypes of a portable high-sensitive a-radiometer.
Potential role of foreign collaborators
Within the present project there are some areas in which collaborators may be involved:
· joint or independent tests of model detectors and a-radiometers developed under the Project at the laboratories of foreign partners;
· discussion of some experimental set ups, including those aimed at obtaining altendant information, provided this will not significantly increase the cost of work;
· participation in commercial projects in order to establish joint production of a-radiometers and their sale.
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