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GSC field crew – measurement of soil gas radon



GSC field crew – measurement of soil gas radon

General Methodology:

Uranium and thorium generate by their decay radioactive gases radon (222Rn, T½ = 3.82 days) and thoron (220Rn, T½ = 54.5 seconds), both sources of alpha radiation, which differ by their half-lives T½. The usual radon and thoron activity concentrations in soil-gas range from 10 to 100 kBq/m3, while some anomalies may attain values up to several thousands of kBq/m3.  The RM-2 Radon detector is designed for in situ rapid and accurate analysis of radon (222Rn) in soil gas.

The RM-2 consists of a set of fifteen ionization chambers, the reader ERM-3 and a soil-gas sampling set.  Samples of soil-gas are collected through hollow steel rods by means of a plastic large-volume syringe and transferred to evacuated ionization chambers.  In order to eliminate thoron, ionization chambers with soil-gas samples are measured with a time delay of 15 minutes after sampling.  Alpha radiation of radon in soil-gas sample gives rise to an ionization current in the ionization chamber, which is measured within 120 s.  The reader displays the concentration of radon in units of volume activity (kBq/m3).

Several different values of radon concentration are reported:

  • Average soil gas radon concentration (kBq/m3). 

  • Average soil gas radon concentration (kBq/m3) using only those samples with greater than 0.7 kBq/m3

  • Median soil gas radon concentration (kBq/m3). 

  • Minimum soil gas radon concentration (kBq/m3), individual measurements less than 0.7 kBq/m3 replaced with a default value of 0.35 kBq/m3

  • Maximum soil gas radon concentration (kBq/m3). 

The soil radon potential index may also be calculated if the soil permeability is known.

 

Instrument:

Sample material: gas

Sample weight: unstated


Analytical Technique:

Hierarchical classification

Technique >> Radiochemical methods >> Natural radiation >> Alpha radiation >> Emanometry

Children

None


Analytical Decomposition:

Hierarchical classification

Decomposition >> None

Children

None


Analytical Methods:

IndexMethod OrderMethod IDQuantityDetection Limit
1  2466     Rn_Ave_1 
2  2467     Rn_Ave_2 
3  2468     Rn_Median 
4  2469     Rn_Min 
5  2470     Rn_Max 

Associated Analytical Packages:

IndexPackage IDPackage Name
1  265     GSC field measurement of soil gas radon and permeability
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