Abstract
A flow-through, ionization-chamber type air sampler for radio-active gases is described. Gamma compensation is achieved by the usual addition of a sealed chamber. However, the two chambers, identical in other respects, orbit about a common axis, thereby occupying the same space in each revolution. Gamma subtraction is thus more effectively achieved than with stationary chambers in areas where external gamma fields are nonuniform or may change spectrally or directionally. The detection limit for radioactive gases in the presence of gamma background is imposed by the subtraction of two large quantities, each of which has statistical fluctuations. Using one-liter chambers, and an electrometer amplifier with a full-scale sensitivity of 10 −13 A and a 50-second time constant, a 50 mR/h gamma exposure rate results in fluctuations corresponding to a standard deviation of approximately 3 × 10 −15 A. In the case of tritium sampling (full scale ≈ 140 μ Ci/m 3), the detection limit in the same gamma field is less than 10 μCi/m 3 after several minutes of observation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
