Delayed coincidence counter for the assay of actinon and thoron

Journal Article · Fri Mar 15 04:00:00 EST 1963 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/JZ068i006p01749· OSTI ID:4726070

Giffin, Charles; Kaufman, Aaron; Broecker, Wallace

A highly sensitive system for the detection of small quantities of Rn²¹⁹ (T_1/2 = 3.92 sec) and Rn²²⁰ (T_1/2 = 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, T_1/2 = 1.8 msec and Po²¹⁶, T_1/2 = 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

Related Subjects

BACKGROUND
CARBONATES
COINCIDENCE METHODS
COUNTERS
DECAY
EFFICIENCY
HALF-LIFE
INSTRUMENTS AND INSTRUMENTATION
POLONIUM 215
POLONIUM 216
PROTACTINIUM 231
RADON 219
RADON 220
SCINTILLATION COUNTERS
THORIUM 232