SPONTANEOUS FISSION RATE MEASUREMENTS BY MEANS OF FAST TIME-OF-FLIGHT MULTIPLICITY ANALYSER (FATIMA)
A fast coincidence device, composed of three plastic scintillation detectors, is aimed to measure the absolute rate of radioactive sources decaying with multiple emission of neutrons and gamma rays. The process to be investigated is the spontaneous fission, and the method is intended for determining the mass of fissile isotopes such as those of plutonium, against a background of (alpha,n) reactions due to the oxygen of PuO-2. Moreover, a time-of-flight analysis, triggered by the coincidence signals, enables us to discriminate between the detected neutrons and gamma rays. Preliminary experiments on spontaneous fission sources such as 244-Cm and 252-Cf showed that, owing to the peculiar features of the fission process not come closer to the conditions required by the coincidence method for an absolute measurement. The further applications to PuO-2 samples and the simulation of bulk source showed evidence of more difficulty to obtain an absolute measurements due to the effects of scattering and absorption of neutrons and gamma rays by the matrix material.
Bibliographic Reference: EUROPEAN APPLIED RESEARCH REPORTS - NUCLEAR SCIENCE AND TECHNOLOGY SECTION, VOL. 7 (1986), NO. 3, PP. 411-450, (EUR 10218 EN).
Availability: Can be ordered online
Record Number: 1989124097700 / Last updated on: 1987-01-01
Available languages: en