Hiroshi Gotoh

Solid angle subtended by a rectangular slit

Abstract A solid angle subtended by a rectangular slit with an arbitrary thickness at an arbitrary point is represented by inverse trigonometric functions.

The detection efficiency and the response function of semiconductor proton recoil counters with axial symmetry to a point neutron source

Abstract The detection efficiency and the response function of semiconductor proton recoil counters with axial symmetry to a point neutron source are given in a single integral form with a composed function of elementary functions as integrand.

Calculation of the self-absorption of gamma rays in a disc shaped source

Abstract Two kinds of calculation methods - a Monte Carlo method and a non-statistical one - are proposed for the self-absorption of gamma rays in a disc shaped source.

Bate- and Gamma-Ray Spectroscopy of 80mBr

Decay of 80m Br was investigated. The half-lives of the isomeric and the ground states of 80 Br were obtained to be 4.42±0.01 h. and 16.8±0.1 min, respectively. Beta-ray, gamm-ray and gamma-gamma coincidence studies were carried out and energies and relative intensities of beta and gamma transitions were determined. Kurie plot analyses of negatrons and positrons give the maximum energies of 2.000±0.016 MeV and 0.850±0.007 MeV, respectively. The 1.478 MeV 0 + level of 80 Se and the 1.320 MeV 0 + and 1.256 MeV 2 + levels of 80 Kr were confirmed.

Calculation of the response function of semiconductor proton recoil counters with a radiator of finite thickness

Abstract A calculation formula for the response function of semiconductor proton recoil counters with a radiator of finite thickness exposed to a parallel neutron beam is expressed in a single integral form with an elementary function as integrated. Numerical examples of the response function calculation are also given.

Measurement of the cross-section for the 115in(n, n′) 115min reaction

Abstract The energy dependent cross-section for the 115 In( n, n′ ) 115 m In reaction was measured in the neutron energy region from 3·37 to 4·89 MeV with a 2 MeV van de Graaff accelerator. A pair of semiconductor proton recoil counters composed of a polyethylene radiator and a silicon detector was used for the absolute measurement of the neutron flux at the indium sample. A comparison of the average cross section, 175 ± 6 mb, which was measured with a fission plate, with the average cross-section calculated with the energy dependent cross-section and the Maxwellian fission neutron spectrum is presented and discussed.

Neutron yields from actinide oxides

Abstract Neutron yields emitted from actinide oxides by spontaneous fission and by the (α, n) reaction of oxygen were measured separately. The measured neutron yields of spontaneous fission were consistent with the neutron yields calculated from ν - values and rates of spontaneous fission. The (α, n) neutron yields calculated from stopping power and thick target yield data were lower than the measured yields by about 10%.

Non-destructive determination of spontaneously fissioning nuclides by neutron coincidence counting using multichannel time spectroscopy

A non-destructive method for determining the amount of actinoids has been developed. The method is based on thermal neutron coincidence counting and employs a selective detection of neutrons resulting from the spontaneous fission of actinoids. The detection system is described in detail and the measurement results of244Cm as an example are presented. The results show that the measured fission rate of244Cm is consistent with the fission rate calculated from ENDF/B-V data and that the amount of244Cm can be determined within about 5% accuracy even in the presence of a large amount of actinoids, for example, up to 2.6·106, 3.6·104, or 1.6·103 times in the mass ratio of239Pu,241Am, or240Pu to244Cm, respectively.

Response function of semiconductor proton recoil counters with axial symmetry to parallel neutron beam

Abstract The respons function of semiconductor proton recoil counters with axial symmetry to parallel neutron beam is represented by elementary functions containing inverse trigonometric functions.

Decay of In108

The decay of In/sup 108/ is investigated by means of Ag/sup 107/ foils irradiated with 38-Mev alpha particles. The half life and decay scheme were determined. (C.E.S.)