Subsoil radioactive gas measuring system
First Claim
1. A subsoil radioactive gas measuring apparatus comprising a probe having a hollow body surrounded by a rigid wall, cap means at an upper end of the probe body for receiving force upon the cap means while driving the probe into a soil to be tested, a cone means at a lower end of the probe body for moving soil laterally while the probe is being driven into soil openings in the probe while the cap means receives force from the soil into the chamber, filter means in the body adjacent the chamber openings for permitting passages of gas from the soil into the chamber and for preventing passage of particles, a detector including statically electrically charged electret means in the chamber for attracting oppositely charged ions and particles to the detector, when ions and charged particles are formed from decay of radioactive gas in the chamber, wherein charge of the detector is changed upon encounters of the attracted ions and charged particles with the detector.
2 Assignments
0 Petitions
Accused Products
Abstract
Radioactive gas, particularly radon, is measured in the subsoil environment by electrostatically charging one or two electrets and placing the electret(s) within a chamber having openings protected by a filter which permits gas to flow through the openings while preventing particles from flowing through the openings. The chamber with the electrostatically charged electret(s) and the detector is placed in a receiver formed within the hollow wall of an elongated probe. Foam cushions surround the chamber and assist in the filtering. An open material, such as steel wool, holds the foam in place and the next lower section of the probe holds the steel wool in place. When sampling is done at only one level, the next lower section is the soil moving nose of the probe. Holes in the side wall near the nose admit subsoil gas into the receiver. When it is desired to sample radioactive gas at several levels, additional sections of the probe have receivers for holding additional chambers and openings near the bottom of each section admit gas into the receivers. After leaving the probe in the soil for a predetermined period, the probe is removed and disassembled. The chamber is removed from the receiver and the surface charge on the detector is measured. Changes in the surface charge are compared with known relations between changes in surface in radioactive decay in the chamber to give amount of radioactive gas that has decayed in the chamber.
42 Citations
20 Claims
- 1. A subsoil radioactive gas measuring apparatus comprising a probe having a hollow body surrounded by a rigid wall, cap means at an upper end of the probe body for receiving force upon the cap means while driving the probe into a soil to be tested, a cone means at a lower end of the probe body for moving soil laterally while the probe is being driven into soil openings in the probe while the cap means receives force from the soil into the chamber, filter means in the body adjacent the chamber openings for permitting passages of gas from the soil into the chamber and for preventing passage of particles, a detector including statically electrically charged electret means in the chamber for attracting oppositely charged ions and particles to the detector, when ions and charged particles are formed from decay of radioactive gas in the chamber, wherein charge of the detector is changed upon encounters of the attracted ions and charged particles with the detector.
- 8. A subsoil radioactive gas measuring apparatus comprising a probe body, a testing chamber connected to the probe body, openings in the testing chamber for admitting gas from the subsoil adjacent the probe body and filter means mounted adjacent the openings in the testing chamber for preventing admission of particles into the testing chamber while permitting passage of gas into and out of the testing chamber and a detector including statically electrically charged electret means in the chamber for attracting oppositely charged ions and particles to the detector, when ions and charged particles are formed from decay of radioactive gas in the chamber, wherein charge of the detector is changed upon encounters of the attracted ions and charged particles with the detector.
- 12. The method of measuring subsurface radioactive gas in soils comprising forcing a probe into a soil, flowing gas into a receiver in the probe, flowing gas through a filter means including a diffusion barrier into a testing chamber, permitting radioactive gas to decay in the testing chamber, attracting ions formed during the decay and charged particles formed during the decay toward a detector which includes an electret having a static charge opposite the charge of the ions and charged particles attracted to the detector, changing charge on a surface of the detector according to encounters by the surface with charged ions and particles attracted to the surface by the static charge and measuring the changed charge on the detector to determine radioactive gas in the subsoil.
- 19. The method of measuring subsurface radioactive gas in soils comprising forcing a probe into a soil, flowing gas into a receiver in the probe, flowing gas through a filter means including a diffusion barrier into a test chamber, permitting radioactive gas to decay in the testing chamber, attracting ions formed during the decay and charged particles formed during the decay toward a detector which includes an electret having a static charge opposite the charge of the ions and charged particles attracted to the detector, changing charge on a surface of the detector according to encounters by the surface with charged ions and particles attracted to the surface by the static charge, repelling charged ions and charged particles of particular charges from a second statically charged electret having a like polarity to the repelled ions and charged particles and having a polarity opposite to the polarity of the first mentioned electret, and measuring the changed charge on the detector determined radioactive gas is the subsoil.
Specification