Measurement of the low energy spectrum of delayed neutrons from 87Br and 88Br precursors
1971; Pergamon Press; Volume: 25; Issue: 11 Linguagem: Inglês
10.1016/0022-3107(71)90049-9
ISSN1878-4410
AutoresN.G. Chrysochoides, J. N. ANOUSSIS, C. Mitsonias, D.C. Perricos,
Tópico(s)Radiation Therapy and Dosimetry
ResumoIn this paper results of the low energy spectrum measurements of delayed neutrons from 87Br and 88Br precursors are reported. 235U was irradiated in the thermal column of “Democritos” 1 MW swimming pool reactor, and bromine isotopes were separated from fission products by a fast radiochemical technique. The measurements were based on a fast time-of-flight beta-neutron coincidence technique, using as detectors the Nuclear Enterprises plastic scintillators NE-102A with a rise time less than 3 nsec. In this technique, the energy resolution becomes satisfactory for the particular requirements of an experiment by suitably choosing the neutron flight distance and the resolving time of the system for a given energy range of interest. In the present experiments the energy resolution was 9 per cent at worst (150 keV), becoming better and better with decreasing neutron energy (5 per cent at 50 keV). Analysis of the obtained data gave a spectrum with several peaks, which could be possibly composed of discrete lines. Specifically, for the mixture 87Br and 88Br the peaks appear at 65–70, 80, 105 and 145 keV, while for 87Br there are indications for peaks at 45, 70 and 110 keV. Experimental work will continue by further improving the technique and extending it to other delayed neutron precursors of interest.
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