Delayed coincidence counter for the assay of actinon and thoron
A highly sensitive system for the detection of small quantities of Rn219 (T1/2 = 3.92 sec) and Rn220 (T1/2 = 54.5 sec) was developed. These isotopes are continually swept from a 5-ml acid solution containing their parents into a highly efficient 2-liter scintillation counter. Through the use of a delayed coincidence technique involving the short-lived decay products of the emanation isotopes (Po215, T1/2 = 1.8 msec and Po216, T1/2 = 0.16 sec), the counter background is substantially reduced (0.03 cpm for actinon and 0.15 for thoron counting). The overall detection efficiencies are 45 and 46 per cent, respectively. With this system as little as 4 x 10–12 gram Pa231 per gram (equivalent to 2 x 10-7 gram U238 per gram) and 2 x 10-8 gram Th232 per gram can be detected in 30-gram samples of carbonate minerals. (auth)
- Research Organization:
- Columbia Univ., Palisades, New York
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-17-016440
- OSTI ID:
- 4726070
- Journal Information:
- Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: 6 Vol. 68; ISSN 0148-0227
- Publisher:
- American Geophysical Union
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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