The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI UMI Microform DP12046
A commercial ionization chamber device has been adapted and calibrated to serve as an accurate, rapid and convenient thoron monitor for experimental and health physics applications. Calibration was achieved by (1) deriving a general expression by which the alphacounting rates of two dust samples (prompt and delayed) can be interpreted in terms of the thoron concentration at the sampling point and (2) building and using a dual dust collector to obtain the necessary data. The monitor can sense pure thoron concentrations as low as 3.7 x 10-6 pc/l., and can sense pure radon at 0.42 of its thoron sensitivity.
The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI UMI Microform DP12046
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