SU426572A1 - Gas proportion inner filling counter - Google Patents

Description

one

The meter can be used for radiometry of radioactive gases, including for determining the content in the air of beta emitters with low decay energy (tritium, carbon-14, etc.).

Among the known constructions of internal filling meters, detectors are most suitable for measuring small activities, in which the cathodes are formed by a system of filaments, and the measuring counter is surrounded by protective meters located in common with it the gas volume and connected with it according to the anti-coincidence scheme. Such meters have a low background and are less susceptible to radioactive contamination, however, due to the presence of anti-matching schemes, they are structurally and technologically complex. I1 require the use of expensive electronic recording equipment. Meter designs are not convenient for decontamination in the event of significant contamination with radioactive substances. The counting characteristics of multi-vacuum counters have a significant slope due to the effect of drawing electrons and ions into the counter from the gap between the cathode and the housing.

The purpose of the invention is to improve the radiometric characteristics of the internal filling meters with a multi-strand cathode (reducing the inclination of the counting plateau and background level), as well as reducing the effect of radioactive contamination of the meter body on its readings.

These goals are achieved by the following means: the meter case is surrounded by an electrically conductive screen, which is supplied with a positive relative to the cathode voltage of such magnitude that the cathode field strength between the screen and the cathode is equal to the internal voltage

counter floor; the multi-strand cathode of the counter is installed from the inner surface of the housing at a distance equal to or greater than the maximum mean free path of the recorded particles in the working gas.

In the proposed counter, the external electrostatic field prevents the penetration of the internal floor of the counter beyond the cathode and the pulling of secondary charges formed in the Layer between the cathode and the body from the radiation of the gaseous sample, radioactive contamination of the surface of the I1 body of the outer background space and gamma into the gas amplification zone radiation. As a result of a clear

electrical limiting of the sensitive volume; the counting characteristic of the device is significantly improved. The level of the background of the instrument is reduced in approximately as many phases as the cross-sectional area of the sensitive volume is smaller than the cross-sectional area of the entire gas volume of the detector. Remove sensitive volume from

Claims (2)

Claim 1. A gas proportional internal filling meter with a multi-filament cathode, characterized in that, in order to improve radiometric characteristics, the meter body is surrounded by an electrically conductive screen located at a positive potential relative to the cathode. .2. Counter by π. 1, the fact is that, in order to reduce the influence of radioactive contamination of the casing on the readings of recording equipment, the distance between the cathode and the inner surface of the casing is equal to the maximum range of alpha or beta particles of the controlled radioisotope. NGO "Search" Order 1980/1 Ed. No. 459 Circulation 649 Subscription Printing house, 2 Sapunova ave.