Method for liquid scintillation counting of radioactive nuclides

摘要

"A method for liquid scintillation counting of the radioactive nuclides of the natural decay chains of Th-232, U-238 and U-235 by detecting decay events of the short-lived members Po-212, Po-214 and Po- 215 of these decay chains by the principle of delayed coincidence, characterized in that a separate pulse height spectrum is recorded for those pulses of the counting device which occur within a fixed short time interval after a preceding pulse. The successive decays cause pairs of quickly succeeding pulses to be detected; the coincidence of these pulses within a brief time interval makes it possible to distinguish the decay events from other decay events. The invention further permits simultaneous counting of different isotopes by fixing several short time intervals following a first pulse, and assigning a second pulse following the first pulse to one of several separate pulse height spectra in accordance with the length of the time interval within which the second pulse occurs."