The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 01, 1989
Filed:
Dec. 01, 1986
John C Dempsey, Salamanca, NY (US);
Payasada Kotrappa, Olean, NY (US);
Rad Elec Inc., Frederick, MD (US);
Abstract
A small enclosed chamber with an electrostatically charged electret attached to the inner chamber wall. A filtered hole in the chamber permits radon or other radioactive gas to enter by diffusion. Positive or negative ions (depending on the polarity of the electret charge) formed in the chamber air by the decay of the radioactive gas move to and collect on the electret surface by virtue of its electrostatic attraction to ions of opposite polarity. These ions accumulate and cause a measurable reduction in the surface voltage of the electret which reduction is proportional to the time integrated concentration of the radioactive gas in the chamber. The electret surface voltage of the reduction value is used to calculate the average concentration of the radioactive gas during the exposure period. The electret thickness and chamber volume can both be increased to increase the sensitivity of the invention to radioactive gases such as radon, tritium or carbon-14 dioxide or such other radioactive gases.