SU397073A1 - Scintillation unit for detecting alpha- and beta-radiation - Google Patents

Abstract

SCINTILLATION UNIT OF DETECTING ALPHA AND BETA RADIATIONS, containing a detector, a ring with a light shielding film attached to it, a photofinishing & hitele, a casing, means for attaching the detector and a ring to the casing, and In order to improve the reliability of light protection, simplify the assembly technology and control of the detection unit, the ring is made in the form of a Z-shaped mandrel, the inner surface of which and matching with it the lateral surface of the detector are conical, and the angles of inclination mated by erhnostey equal and each of them does not exceed the self-locking angle, the larger end face of the mandrel is equal to the maximum diameter of the flange of the detector in the region of its attachment to the casing, and the light shielding film is fixed to a lower neck flange.

Description

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The invention relates to radioactive radiation detection devices and can be used, in particular, to register alpha and beta radiation.

In scintillation detection units, the detector's light shielding — in the presence of external light — is mandatory. It is important that the light produced by the scintillating substance 4 is separated from the surrounding external light. For this purpose, the detector from the side of the scintillating substance is covered with light shielding screens-1.

Several methods of light shielding are known that are used in scintillating dionic detection units, for example, by applying several layers of aluminized plastic to the scintillor of a sufficiently large thickness by spraying when exposed to water vapor, or sequentially applying several layers of transparent plastic with aluminum filler to the scintillator. special solutions, or direct application to the photomultiplier one after another by scintillating 1 of its reflective and light-protective layers, the latter being applied by evaporation in a vacuum,

However, detectors made by such methods are not repairable. Special equipment and slats are required for their manufacture. Technological processes. In addition, the design of the detection units is complicated when using photomultipliers without directly applying scintillating reflective and light-protective layers.

An example of a simpler implementation of the light shielding of a detector in scintillation detection units is the light shielding of two layers of metallized (5-10 micron polyethylene terephthalate film,

The film is fixed on a flat thin (up to 1) ring and installed through a rubber gasket (cuff) on the detector. The film is pressed onto the detector by a washer using a cap nut, which is screwed onto the casing of the detection unit (sensor K) The film can also be placed in the housing (container), in which case it is pressed onto the detector by means of rolling. Instead of a washer, a protective net is usually used that protects film from mechanical damage and radioactive contamination.

However, such a construction of light protection has significant drawbacks.

Due to the low stiffness of the ring, the fire shield (film) often tears. Increasing the ring thickness significantly impairs the registration efficiency due to the removal of the source.

radiation from the scintillating layer of the detector.

In addition, high precision is required in the manufacture of parts carrying out a light emission detector, and their fixation when assembling the detecting unit, as a result, the design of the detector and its attachment unit is complicated due to the installation of pins, making grooves and holes in the parts of the detector and light shielding, as well as the sealing of the detection unit.

In the process of assembling the detector when the cap nut is tightened and a significant deformation of the rubber gasket (cuff) is on the light shielding screen (the film may experience defects due to local discontinuities of the sprayed aluminum layer, usually at the periphery, in the transition from one surface to another.

With this design, a double quality control of the light shield is required: before and after installing it with the detector in the detecting unit, and a long time is required to find small, invisible, defects in the light shield installed with the detector in the detecting unit.

The purpose of the invention is to increase the reliability of light protection, simplify the assembly technology and control of the detection unit.

This is achieved by the fact that in the proposed scintillation detection unit comprising a detector, a ring with a light shielding film attached to it, a photomultiplier, a housing, means for attaching the detector and the ring to the housing, the ring is a Z-shaped mandrel whose inner side surface and the lateral surface of the detector mating with it is tapered. At the same time, the angles of inclination of the mating surfaces are equal and each of them does not exceed the self-locking angle. The larger end flange of the mandrel is equal to the maximum diameter of the detector in the zone of its attachment to the casing, and the light shielding film is fixed on the smaller end flange

The drawing shows in section a part of the scintillation alpha-radiation detecting unit - light protection and fixing unit of the detector to the casing of the detection unit.

A photomultiplier 2 is installed in the casing 1 of the detecting unit; detector 3 with light composition ZnS (A) has been lapped to the photocathode. The detector has a mandrel 4 with metalized polyethylene terephthalate film 5. It is attached to the flanges of the detector and mandrel with an elastic U-shaped cuff b, which may also be elongated 3 3970734

the tight part worn tightly on the photomultiplier. the detector and mandrels are made of a cone. Through the washer 7 with a nut 8. the detector is different with a slope angle not exceeding

the mandrel is fastened to the self-locking block housing. Such a design. From mechanical detailing allows to protect

damage the light shielding film of the pre-mandrel against rotation, tightens the ring 9, which, by lining the nut and rejecting

cast onto mandrel. This ring of my-pins in the form of pins

It can be provided with a protective net. And the holes in these parts are matching the side surfaces.

Claims (1)

ALTERA AND BETA RADIATION SCINTILLATION BLOCK, containing a detector, a ring with a light-protective film attached to it, a photomultiplier, a casing, means for attaching the detector and a ring to the casing, distinguishing it by the fact that, in order to increase the reliability of light protection, simplification of the assembly and control technology of the detecting unit, the ring is made in the form of a Z-shaped mandrel, the inner surface of which and the side surface of the detector mating with it are made conical, with the slope angles of the mating surfaces p each of them does not exceed the angle of self-braking, the larger end flange of the mandrel is equal to the maximum diameter of the detector in the area of its attachment to the casing, and the light-protective film is fixed to the smaller end flange. δ Z δ / ^ 22222221