Measurement cavity for improving positively charged 218Po collection efficiency through annular electrode and method

Abstract

The invention discloses a measurement cavity for improving positively charged 218Po collection efficiency through an annular electrode and a method. An inner wall of the measurement cavity is a conductive layer, an air outlet pipe and an air inlet pipe are arranged on a wall plate, a semiconductor detector is arranged on an insulation end cover, the first annular electrode is arranged at a lower part of the insulation end cover, a binding post on the first annular electrode penetrates an upper part of the insulation end cover, and the end cover is fixed at an opening end of a cavity; a measurement method comprises the following steps: the air inlet pipe on the cavity is connected with a radon chamber; the semiconductor detector, the conductive layer and the first annular electrode are connected with a high-voltage module through conductor wires, a sampling pump is connected with the air outlet pipe, the sampling pump is started to import the air of a radon chamber, and the radon concentration in the chamber is same as that in the radon chamber. The voltage between the semiconductor detector and the conductive layer is adjusted through the high-voltage module, the 218Po decay counting rate measured by the semiconductor detector is obtained by utilizing a secondary instrument, and then the 218Po decay counting measured through the semiconductor detector is analyzed and computedto obtain the radon concentration by using the secondary instrument.

Description

technical field [0001] The invention relates to nuclear radiation detection technology, in particular to a method of using a ring electrode to effectively improve the detection of positively charged radon by the electrostatic collection method. 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 for humans. There are many radon measurement methods and instruments based on different measurement principles. Among them, the electrostatic collection radon measurement instrument has the ability to distinguish energy spectrum due to its high degree of automation. 220 The interference of Rn has been widely used. The so-called electrostatic collection method is to have a measuring chamber, the measuring chamber is generally hemispherical or cylindrical, there is a semiconductor detector on the upper part of the measuring chamber, and a high voltage is applie...

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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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