SU588817A1 - Device for measuring concentration of radioactive emanations - Google Patents

Abstract

MEASUREMENT DEVICE CONCENTRATION OF RADIOACTIVE EMANATION IN AIR containing a camera with an alpha-sensitive film and an air penetration opening, characterized in that for the purpose of separate determination of radioactive emanation, mainly radon and toron, during measurements for a long period time, a second film is placed in the chamber, and an element, mainly a gas-permeable filter, is placed between the hole and the second film to increase the time of emanation from the inlet opening to the second film. @

Description

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N The scope of the invention is the search for deposits of radioactive elements and elements, in paratenetically bound radioactive elements. Devices are known to measure concentrations of radioactive emanations based on alpha registration from radon, toron and actinon radiation and their short-lived daughter decay products. ionization or scintillation emanometers 1. A disadvantage of devices for measuring the concentration of emanation using emanometers is one moment of measurement results. This is due to the fact that the analyzed air is taken into the measuring chamber, and therefore the measurement result: significantly depends on the temporal variations in the concentration of emanation and the sampling conditions (for example, when measuring soil air, the character of loose sediments and their moisture content , the degree of tamponage of the wellheads from which water is taken, etc.), therefore, the results of repeated measurements of the concentration of emanation within the same point may differ from the primary one by several times. The advantage of using emanometers is the possibility of separable definitions of radon, toron and actinon, which is important for the interpretation of measurement results. However, the simultaneity of the measurements reduces. - there is no advantage. A device for measuring the dose of alpha radiation that accompanies the decay of radioactive emanations of radon, toron and actinon is known, which is based on the tracks of alpha particles on special sensitive films 2 The disadvantage of this device is the impossibility of separate determination of the concentration of radioactive emanations of radon, toron and action The closest in technical essence of the present invention is a device for measuring the concentration of radioactive emanation, containing a chamber with a film sensitive to o (, - particles, and air penetration hole C. This device is placed in the soil for 30 days, after which the film is removed and etched with alkalis. The number of the formed tracks is a characteristic of the concentration of radioactive emanation in the soil air. temporal variations of the concentration of emanation due to measurement in a long period of time. A disadvantage of the known device is the impossibility of separate determinations centration of radon, thoron and Aktion. In this case, if the concentration of action in the air is negligibly small compared to the radon concentration and lies below the error threshold for determining the concentration of tracks in the film, the toron concentration is comparable with the radon concentration and in many cases may exceed it. Thus, when conducting emanational. measurements using a known device are performed by counting the tracks of both radioactive emanations. If a . taking into account that radon and thoron are regenerated in completely different geological objects, and are also present everywhere in the air under conditions of normal fields, then the need for I-parting definitions becomes obvious. For separate determination of radioactive emanations, such as radon and toron, during measurements for a long period of time in the proposed device, a second film is placed in the chamber and an element, for example, a gas-permeable filter, is inserted into the chamber, dp increasing the time of passage of the emanation from the inlet. L. Hole to the second film. The drawing shows the proposed device, a general view,. The device contains a camera 1 with inlets 2 and special alpha-sensitive films 3 and 4 placed in it, as well as element 5 for increasing the time of passage of emanation from the inlets to the film 4, As such an element can be used, for example, any porous filter. The device works as follows. . Through the inlets 2 into the cavity 1 comes due to gas transfer mechanisms (for example, interfusions) the analyzed air containing radioactive emanations. Dissipating in the lower part of the chamber (up to element 5) emanaci forms in a row; alpha-particle tracks in the film Z. The number of such tracks is determined by the expression. n .. ,, Tn ..Rn N4 1 where N-j is the total number of tracks in captivity-Ki 3; . N is the number of tracks due to id alpha particles of thoron; - the number of tracks due to alpha particles of radon.

The emanaci flowing through the porous partition into the upper part of the chamber, depending on the properties of the element, which increases the passage of air from the inlet to the film 4, will be depleted in toron compared to radon due to the difference in the half-lives of radon (Tcp 3.8 days) and toronii ( TTP 54 c).

The number of tracks in the top 4 film is determined by the expression;

yp

Md

where N4 is the number of tracks in film 4, L is a coefficient showing the proportion of toron decaying when air moves from film 3 to film 4, B is a similar factor

for radon.

In the extreme case, when the Thoron concentration can be neglected (the time of passage of air to the upper part of the chamber exceeds YuTtz), the number of tracks in film 4 is determined by the expression

. - ". (3) ..

The coefficients A, B, C are determined by calibrating the proposed

devices in the atmosphere of pure radon and pure toron, and the thickness of the porous JToro filter is chosen experimentally.

The joint solution of equations (1) and (3) or (1) and (2) allows determining the separate concentration of radon and toron in the analyzed air by the determined values of N and N4 or - H and 4 4.

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The technical and economic effect of the application of the proposed device lies in the fact that with almost the same productivity of work that exists when using the prototype (only the track counting operation in film 4 is added), additional valuable geological information is obtained, which allows to judge the nature of the geological object , causing abnormal concentrations of emanation, according to the ratio of radon and thoron in the analyzed air.

Claims (1)

DEVICE FOR MEASUREMENT ”) CONCENTRATION OF RADIOACTIVE EMANATIONS IN AIR, containing a chamber with a film sensitive to alpha particles, and an opening for air penetration, characterized in that, for the purpose of separate determination of radioactive emanations, mainly radon and thoron, during measurements over a long period of time, a second film is placed in the chamber and an element, mainly a gas-permeable filter, is placed between the hole and the second film to increase the emanation time from the inlet to the second film. <g