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The neutron spectrum of AmBe neutron sources

1973; Elsevier BV; Volume: 111; Issue: 3 Linguagem: Inglês

10.1016/0029-554x(73)90199-7

1878-3759

A.D. Vijaya, Arun Kumar,

Radiation Therapy and Dosimetry

Neutron spectra of 241Am9Be(α,n) sources have been calculated by using the most recent data on angular distributions. The contribution from the multibody break-up reaction 9Be(α,αn)8Be has also been incorporated by using the measured angular distributions of this reaction at various energies. Modifications to the spectrum due to the secondary interactions in the source such as elastic scattering with beryllium, oxygen, and americium, and the 9Be(n,2n) and 241Am(n,f) reaction have been investigated by means of Monte Carlo and other quadratures, as earlier calculations were uncertain below 2.5 MeV. The neutron spectrum of a 1 Ci 241Am9Be source was measured with nuclear emulsions. Comparison of the spectra obtained by other methods with the present measurement shows little discrepancy among the measured spectra, except that the 0.3 MeV peak is not observed in the emulsion measurements. The present calculations show that inclusion of secondary interactions does not account completely for the increased intensity in the lower end of the spectrum. These interactions account for the variation of the spectrum with the size and beryllium content of the source.