Ionization chamber for monitoring radioactive gas

A radioactive gas monitoring apparatus comprising a container with electrically conductive surfaces, openings in the container for allowing gases to enter the container, a filter over the openings to exclude entry of radon progeny attached to particles, a first electret positioned within the container for holding an electrostatic charge which collects the charged substances formed in the container by radiation from the radioactive gases and their progeny, a second electret positioned within the container spaced from the first electret, the second electret having an electrostatic charge which is opposite to an electrostatic charge of the first electret for repelling charged substances in the gas by the second electret toward the first electret.

The method of monitoring radioactive gases including radon, said method comprising using a container having electrically conductive surfaces such that an enclosed electric field attracts charged ions formed in the container by decay radiations of the radioactive gases within the container to a surface of a positively or negatively charged electret mounted within the container and neutralizing the electret such that the electret surface charge changes in proportion to the number of radioactive decays occuring within the container.

A method of monitoring radioactive gases including radon, said method comprising using a container having electrically conductive surfaces such that an enclosed electric field attracts charged ions formed in the container by decay radiations of the radioactive gases within the container toward a surface of a positively or negatively charged electret mounted within the container, placing a detector cap of the same material as the electret close to and in the electric field of the electret such that the surface charge on the detector cap increases in proportion to the number of radioactive decays occurring within the container.

A method of monitoring a radioactive gas comprising increasing gas volume adjacent a charged electret, passing the radioactive gas including radon through a filter into an opening of a container having electrically conductive surfaces, attracting ions formed by decay radiation of the radioactive gas within the container to the surface of the charged electret mounted within the container, reducing the charge of the electret such that the electret surface charge changes at a rate proportional to the concentration of the radioactive gas, and reducing gas volume adjacent the electret when not in use.

A method of monitoring a radioactive gas comprising increasing gas volume adjacent a charged electret, passing the radioactive gas including radon through a filter into an opening of a container having electrically conductive surfaces, attracting ions formed by decay radiation of the radioactive gas within the container toward the surface of the charged electret mounted within the container, placing a detector cap of the same material as the electret close to and in the electric field of the electret such that the surface charge on the detector cap increases in proportion to the number of radioactive decays occurring within the container, and reducing gas volume adjacent the electret when not in use.

A radioactive gas monitoring apparatus comprising a container formed of plastic having a surface which is electrically conductive and having a cover, openings in the container for allowing gases to enter the container, a filter to exclude particles and radon progeny, a first electret positioned within the container for holding an electrostatic charge which collects the charged substances formed in the container by radiation from the decaying radioactive products, a removable means connnected to the container for mounting the electret, and means for reducing the volume of gas exposed to the electret when the chamber is not in use.

A radioactive gas monitoring apparatus comprising a container formed of an electrically conductive material and having a cover, openings in the container for allowing gases to enter the container, a filter for excluding particles and radon progeny, an electret positioned within the container and comprises means for holding an electrostatic charge which collects the charged substances formed in the container by radiation from the decaying radioactive products, a removable means connected to the container for mounting the electret, and means for reducing the volume of gas exposed to the electret when the chamber is not in use.