Discriminating electret radioactivity detector system and method for measuring radon concentration
CA 2053237 C · Owner: West, James E. · Inventors: Dorfi, Kurt; West, James E.; Sessler, Gerhard M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The detector system includes three substantially similar detectors each of which includes an ionization chamber having a pedestal therein mounting a charged electret. Two chambers are completely sealed except for an equalization aperture. However, gamma rays produce ionization that neutralizes portions of the electret charge in these sealed chambers. The third detector has filtered inlet openings which permit entry of radon gas, and, responds to gamma rays and radon gas. Each detector is a canister including a lid having a round base surrounded by a cylindrical wall. The canister body is a circular base surrounded by a cylindrical wall that nests within the lid with a telescopic fit. A …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 22, 1991 and granted February 13, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 22, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 22, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.