Measurement cavity for improving positively charged 218Po collection efficiency through multi-detector and method

Abstract

The invention discloses a measurement cavity for improving positively charged 218Po collection efficiency through multi-detector and 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 plurality of semiconductor detectors is arranged on an insulation end cover in an annular way to form a first annular measurement ring, and the end cover is fixed at an opening end of a cavity; a measurement method comprises the following steps: the air inlet pipe is connected with a radon chamber, the semiconductor detectors are connected with a high-voltage module after being serially connected through a conductor wire, the conductive layer is connected with the high-voltage module through the conductor wire, a sampling pump is connected with the air outlet pipe, the sampling pump is started to import the air of the 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 is obtained by utilizing a secondary instrument, the counting rate is risen along the rise of the voltage, and the adjusting is stopped when the voltage is continuously boosted and the counting rate basically keeps constant. The collection efficiency ofthe 218Po is improved through the method disclosed by the invention, and then the 218Po decay counting is analyzed and computed to 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 multi-detector method 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 applied between t...

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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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