Method for continuously measuring concentrations of thoron daughters

Abstract

The invention relates to a monitoring technology for radioactive aerosol in an environment and discloses a method for continuously measuring concentrations of thoron daughters in the environment for limited times without replacing filter membranes. The method includes: measuring concentrations and of 220Rn daughters in a to-be-measured environment by primary sampling, and then, using an alpha-particle detector for measuring integral counting Nj(alpha)[Tj1, Tj2] and Nj(alpha)[Tj2, Tj3] of 8,78MeV alpha-particles emitted by a sample obtained by jth sampling within the time periods of [Tj1, Tj2] and [Tj2, Tj3] after continuing sampling for t0min without replacing the filter membranes; computing to obtain Nj''(alpha)[Tj1, Tj2] and Nj''(alpha)[Tj2, Tj3] according to the formulas (19a) and (19b); computing concentrations and of the 220Rn daughters in the to-be-measured environment according to the formula (20).

Description

technical field

[0001] The invention relates to a monitoring technology of radioactive aerosol in the environment, which is a method for continuously measuring the concentration of thoron progeny in the environment for a limited number of times without replacing the filter membrane. Background technique

[0002] Thoron Jet (i.e. 220 Rn) and radon (ie 222 Rn) are both radioactive noble gases and are one of the main sources of natural radiation exposure. 222 Rn is almost everywhere 220 Rn. But people are concerned about the environment 220 Much less attention has been paid to the hazards of Rn and its progeny, due to the fact that in most cases, on the one hand, 220 The doses due to Rn and its progeny are 222 The comparison of Rn and its daughters is almost negligible ( 222 Rn, 220 For the decay chain of Rn see figure 1 ),on the other hand 220 Rn has a very short half-life (55.6s), and the environmental 220 Rn is unevenly distributed, 220 The equilibrium relationsh...

Examples

Embodiment Construction

[0107] In order to verify the reliability of the continuous measurement method, the continuous measurement method and the standard based on the α energy spectrum method were carried out. 220 A comparative study of methods for determining the reference levels of Rn daughters (referred to as reference methods). The α energy spectrometer of ORTECT company was selected for 220 Alpha spectroscopy measurements of Rn progeny. The sampling object is the radon laboratory of Nanhua University with a volume of 2.7m 3 of 220 Rn room, the 220 Rn room has 80-3000Bq / m 3 of 220 The ability to regulate the level of Rn progeny, the cellulose acetate filter membrane with a pore size of 0.8μm is preferably pressed at a constant flow rate of 5L / min image 3 Samples shown are taken from the measurement environment. In order to avoid the difference in the daughter body concentration caused by the different positions of the sampling ports, this study adopts the experimental test plan of sampli...

technical field

[0001] The invention relates to a monitoring technology of radioactive aerosol in the environment, which is a method for continuously measuring the concentration of thoron progeny in the environment for a limited number of times without replacing the filter membrane. Background technique

[0002] Thoron Jet (i.e. 220 Rn) and radon (ie 222 Rn) are both radioactive noble gases and are one of the main sources of natural radiation exposure. 222 Rn is almost everywhere 220 Rn. But people are concerned about the environment 220 Much less attention has been paid to the hazards of Rn and its progeny, due to the fact that in most cases, on the one hand, 220 The doses due to Rn and its progeny are 222 The comparison of Rn and its daughters is almost negligible ( 222 Rn, 220 For the decay chain of Rn see figure 1 ),on the other hand 220 Rn has a very short half-life (55.6s), and the environmental 220 Rn is unevenly distributed, 220 The equilibrium relationsh...

Examples

Embodiment Construction

[0107] In order to verify the reliability of the continuous measurement method, the continuous measurement method and the standard based on the α energy spectrum method were carried out. 220 A comparative study of methods for determining the reference levels of Rn daughters (referred to as reference methods). The α energy spectrometer of ORTECT company was selected for 220 Alpha spectroscopy measurements of Rn progeny. The sampling object is the radon laboratory of Nanhua University with a volume of 2.7m 3 of 220 Rn room, the 220 Rn room has 80-3000Bq / m 3 of 220 The ability to regulate the level of Rn progeny, the cellulose acetate filter membrane with a pore size of 0.8μm is preferably pressed at a constant flow rate of 5L / min image 3 Samples shown are taken from the measurement environment. In order to avoid the difference in the daughter body concentration caused by the different positions of the sampling ports, this study adopts the experimental test plan of sampli...

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