The ring electrode increases the positively charged 218 Measuring cavity and method for po collection efficiency

Abstract

The ring electrode increases the positively charged 218 The measurement chamber and method of Po collection efficiency, the inner wall of the measurement chamber is a conductive layer, the wall plate is provided with an air outlet pipe and an air inlet pipe, the semiconductor detector is installed in the center of the insulating end cover, and the first ring electrode is installed at the lower part of the insulating end cover. The terminal on the first ring electrode passes through the upper part of the insulating end cap, and the end cap is fixed on the open end of the cavity. The measurement method is as follows: the inlet pipe on the cavity is connected to the radon chamber, the semiconductor detector, the conductive layer and the first ring electrode are respectively connected to the high-voltage module through wires, the sampling pump is connected to the outlet pipe, the sampling pump is turned on, and the air in the radon chamber is introduced to make the cavity The radon concentration in the body is the same as in the radon room. The high-voltage module separately adjusts the voltage between the conductive layer, the semiconductor detector and the surface of the first ring electrode, and uses the secondary instrument to obtain the voltage measured by the semiconductor detector. 218 The Po decay count rate is obtained by measuring the semiconductor detector with a secondary instrument 218 The concentration of radon is obtained by analysis and calculation of Po decay counting.

Description

technical field [0001] The invention relates to nuclear radiation detection technology, in particular to a radon measuring instrument using an electrostatic collection method to effectively improve the detection of positively charged radon 218 Measuring cavity and measuring method of Po collection efficiency. Background technique [0002] Radon in the environment ( 222 Rn) is the main source of natural radiation to humans. There are many kinds of radon measurement methods and instruments based on different measurement principles. Among them, the electrostatic collection method radon measuring instrument has the ability of energy spectrum resolution due to its high degree of automation. 220 Rn interference has been widely used. The so-called electrostatic collection method has a measuring cavity, which is generally hemispherical or cylindrical. There is a semiconductor detector on the upper part of the measuring cavity. A high voltage is applied between the measuring cavit...

AI Technical Summary

Problems solved by technology

This results in the measurement of positively charged 218 The drift velocity of Po under the action of the electrostatic field is small, and the collection time is long. During the collection process, it interacts with negatively charged OH - The probability of ion recombination is large, so that the positively charged 218 The efficiency of Po being collected to the surface of the detector by the electrostatic field is not high, and the detection sensitivity of the radon detector is low

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