Kazunori Yuasa

Differential Elastic Scattering of 14 MeV Neutrons in Aluminum, Iron, Lead and Bismuth for Large Angles

The absolute differential cross sections for the elastic scattering of 14 MeV neutrons in Al, Fe, Pb and Bi have been measured for large angles up to 170°. The neutrons generated by 3 T( d , n ) 4 He reactions were scattered by the disk-shaped scatterer, and counted by the n -α coincidence circuit with the resolving time of 4 ns. An anticoincidence method was used to reduce the accidental coincidences between the α-particles and the neutrons which run directly to the detector from the target. Except for the lighter nucleus, the angular distributions obtained fit fairly well with distributions based on the optical model theory employing a surface imaginary part and a real spin-orbit coupling term.

On the Ionization-energy Relation for Alpha-particles in Air

To investigate the effect of columnar recombination on the ionization measurement in air, the ratio of the specific ionizations at two fixed residual ranges for polonium alpha-particles was measured with a shallow ionization chamber under various field strengths and angles between the field and the alpha-track. It was found that the observed ratio varies appreciably with varying field strength and angle. It was shown that the observed variation of the ratio can be explained by the effect of columnar recombination and agrees qualitatively with Jaffes theory. The value of the parameter b in Jaffes formula, which gives the best agreement with the experiments, was newly determined as 9.5×10 -4 for alpha-particles in atmospheric air. The observed specific ionization curve was corrected for recombination by Jaffes theory. Then, the corrected curve was integrated and the true ionization-range relation free from recombination was determined. By comparing this relation with the fixed points of the range-energy ...

The Reactions Li7(p, n)Be7, B11(p, n)C11 and Al27(p, n)Si27 at 8 to 14 MeV

The ( p , n ) reactions for lithium, boron and aluminium targets were studied by using two kinds of proton-recoil, fast-neutron spectrometers. One is an addition type originated by Calvert, Jaffe and Maslin, the other is a type with hydrogen gas radiator. The angular distributions of Li 7 ( p , n )Be 7 neutrons corresponding to the ground and the 0.43 MeV excited states doubles at 8.1 to 14.1 MeV of proton energies and corresponding to the 4.65 MeV excited state of Be 7 at 14.1 MeV of proton energy were obtained. Using the activation method, the excitation curve of this reaction was observed with 15 MeV proton beam. The angular distributions of neutrons from the reaction B 11 ( p , n )C 11 (the ground state) at 8.1 to 14.1 MeV and from the reactions Al 27 ( p , n )Si 27 (the ground and the excited states) at 14.1 MeV of proton energy were also observed. The theory of Austern, Butler and McManus does not agree with the obtained results in the case of the reaction B 11 ( p , n )C 11 , but agrees with that i...The (p,n) reactions for lithium, boron, and aluminum targets were studied using proton-recoil, fast-neutron spectrometers. The angular distributions of Li/sup 7/(p,n)Be/sup 7/ neutrons corresponding to the ground and the 0.43 Mev excited states at 8.1 to 14.1 Mev and corresponding to the 4.65 Mev excited state of Be/sup 7/ at 14.1 Mev were obtained. Using the activation method, the excitation curve of this reaction was observed with a 15 Mev proton beam. The angular distributions of neutrons from the reaction the reactions Al/ sup 27/(p,n)Si/sup 27/ (the ground and the excited states) at 14.1 Mev were also observed. The theory of Austern, Butler, and McManus does not agree with the obtained results in the case of the reaction B/sup 11/(p,n)C/sup 11/ but agrees with that in the reaction Al/sup 27/(p,n)Si/sup 27/. It was observed that, for the reaction B/sup 11/(p,n)C/sup 11/, the isotropic parts of the angular distributions of neutrons became larger as the incident proton energies decreased and, in the cases of the reactions of Li/sup 7/(p,n)Be/sup 7/ and B/sup 11/(p, n)C/sup 1 the angular distributions of neutrons showed large variations for the different proton energies. (auth)The ( p , n ) reactions for lithium, boron and aluminium targets were studied by using two kinds of proton-recoil, fast-neutron spectrometers. One is an addition type originated by Calvert, Jaffe and Maslin, the other is a type with hydrogen gas radiator. The angular distributions of Li 7 ( p , n )Be 7 neutrons corresponding to the ground and the 0.43 MeV excited states doubles at 8.1 to 14.1 MeV of proton energies and corresponding to the 4.65 MeV excited state of Be 7 at 14.1 MeV of proton energy were obtained. Using the activation method, the excitation curve of this reaction was observed with 15 MeV proton beam. The angular distributions of neutrons from the reaction B 11 ( p , n )C 11 (the ground state) at 8.1 to 14.1 MeV and from the reactions Al 27 ( p , n )Si 27 (the ground and the excited states) at 14.1 MeV of proton energy were also observed. The theory of Austern, Butler and McManus does not agree with the obtained results in the case of the reaction B 11 ( p , n )C 11 , but agrees with that i...

THE REACTIONS Li

The ( p , n ) reactions for lithium, boron and aluminium targets were studied by using two kinds of proton-recoil, fast-neutron spectrometers. One is an addition type originated by Calvert, Jaffe and Maslin, the other is a type with hydrogen gas radiator. The angular distributions of Li 7 ( p , n )Be 7 neutrons corresponding to the ground and the 0.43 MeV excited states doubles at 8.1 to 14.1 MeV of proton energies and corresponding to the 4.65 MeV excited state of Be 7 at 14.1 MeV of proton energy were obtained. Using the activation method, the excitation curve of this reaction was observed with 15 MeV proton beam. The angular distributions of neutrons from the reaction B 11 ( p , n )C 11 (the ground state) at 8.1 to 14.1 MeV and from the reactions Al 27 ( p , n )Si 27 (the ground and the excited states) at 14.1 MeV of proton energy were also observed. The theory of Austern, Butler and McManus does not agree with the obtained results in the case of the reaction B 11 ( p , n )C 11 , but agrees with that i...The (p,n) reactions for lithium, boron, and aluminum targets were studied using proton-recoil, fast-neutron spectrometers. The angular distributions of Li/sup 7/(p,n)Be/sup 7/ neutrons corresponding to the ground and the 0.43 Mev excited states at 8.1 to 14.1 Mev and corresponding to the 4.65 Mev excited state of Be/sup 7/ at 14.1 Mev were obtained. Using the activation method, the excitation curve of this reaction was observed with a 15 Mev proton beam. The angular distributions of neutrons from the reaction the reactions Al/ sup 27/(p,n)Si/sup 27/ (the ground and the excited states) at 14.1 Mev were also observed. The theory of Austern, Butler, and McManus does not agree with the obtained results in the case of the reaction B/sup 11/(p,n)C/sup 11/ but agrees with that in the reaction Al/sup 27/(p,n)Si/sup 27/. It was observed that, for the reaction B/sup 11/(p,n)C/sup 11/, the isotropic parts of the angular distributions of neutrons became larger as the incident proton energies decreased and, in the cases of the reactions of Li/sup 7/(p,n)Be/sup 7/ and B/sup 11/(p, n)C/sup 1 the angular distributions of neutrons showed large variations for the different proton energies. (auth)The ( p , n ) reactions for lithium, boron and aluminium targets were studied by using two kinds of proton-recoil, fast-neutron spectrometers. One is an addition type originated by Calvert, Jaffe and Maslin, the other is a type with hydrogen gas radiator. The angular distributions of Li 7 ( p , n )Be 7 neutrons corresponding to the ground and the 0.43 MeV excited states doubles at 8.1 to 14.1 MeV of proton energies and corresponding to the 4.65 MeV excited state of Be 7 at 14.1 MeV of proton energy were obtained. Using the activation method, the excitation curve of this reaction was observed with 15 MeV proton beam. The angular distributions of neutrons from the reaction B 11 ( p , n )C 11 (the ground state) at 8.1 to 14.1 MeV and from the reactions Al 27 ( p , n )Si 27 (the ground and the excited states) at 14.1 MeV of proton energy were also observed. The theory of Austern, Butler and McManus does not agree with the obtained results in the case of the reaction B 11 ( p , n )C 11 , but agrees with that i...

sup 7

Energy spectra of charged π-mesons produced in C, Al and Cu bombarded by a 345 MeV proton beam were obtained with nuclear emulsions. The production cross sections of π + - and π - -mesons from aluminium are (5.3±1.2) 10 -28 cm 2 ster. -1 and (1.9±0.8) 10 -28 cm 2 ster. -1 respectively. In case of copper they are (1.2±0.2) 10 -27 cm 2 ster. -1 and (3.6±1.0) 10 -28 cm 2 ster. -1 respectively. Comparing with the cross section of π-mesons from carbon obtained by Richman et al. it is found that the cross section for charged π-meson production varies roughly as mass number A for small A.