K. Nisimura

Analyzing powers and cross sections in elastic p-d scattering at 65 MeV

Abstract Analyzing powers and differential cross sections for p - d elastic scattering have been measured at 64.8 MeV. The angular distributions cover center-of-mass angles between 8° and 169°. The relative uncertainties of the analyzing power measurement are typically ± 0.005 at c.m. angles less than 80° and are in general ± 0.015 at the remaining angles. The absolute scale of the analyzing power measurement has an uncertainty of ± 0.013. The data are compared with three-body calculations based on the Faddeev theory. In contrast with the differential cross sections, the analyzing powers could not be reproduced without the D-wave nucleon-nucleon interactions.

Polarization measurements for P-12C elastic scattering between 40-75 MeV

Abstract Absolute values of the polarization in p- 12 C elastic scattering have been measured at 60.0 and 64.5 MeV at 47.5° in the laboratory system using a double scattering method and a method to measure an asymmetry with a polarized beam. The results are P (60.0 MeV, 47.5°) = 0.965 ± 0.011 and P (64.5 MeV, 47.5°) = 0.975 ± 0.11. Based on these values, the polarization measurements have been extended to the energy range from 40–75 MeV at several angles round 47.5° using the polarized proton beam and the energy degrader. Differential cross sections and polarizations from 15–115° are also presented at 65 MeV. These data will be valuable for the monitoring of beam polarization in this energy region.

Polarization and cross section measurements for p-4He elastic scattering at 45, 52, 60 and 65 MeV

Abstract Angular distributions of the analyzing power and the cross section for p- 4 He elastic scattering have been measured at E = 45.0, 52.3, 59.6 and 64.9 MeV. The data were taken between 15° and 160° lab, though the measurements were extended to 5.5° in order to investigate the Coulombnuclear interference at 52.3 and 64.9 MeV. The relative uncertainties of the analyzing power measurements are typically ± 0.01. The analyzing power measurements provide an accurate proton polarization analyzer up to 65 MeV. The analyzing power near θ c.m. = 140° exceeds 90 % at all energies and shows very little energy dependence. But at angles smaller than 120°, the angular distribution of the analyzing power changes in shape and magnitude with energy.

Measurements of analyzing powers Ay, Axx, Ayy and Axz in dp elastic scattering at Ed = 56 MeV

Abstract The differential cross section and all components of the analyzing powers A y , A xx , A yy and A xz have been measured in dp elastic scattering at 56 MeV. This is the first measurement of A xz in the cyclotron energy region. A xz has been measured with the beam polarized in the horizontal plane using the polarization tagging method. Faddeev calculations have been performed for four cases of the NN interaction. The Coulomb correction gave smaller effects at the present energy than at lower energies. Three of them reproduce the experimental data well. The agreement between the calculations and data for A xz was better than that reported at lower energy. The deuteron asymptotic D- to S-state ratio has been obtained and is consistent within the limits of uncertainty with previously obtained values.

Measurements of proton-proton differential cross sections at 5, 7 and 8 MeV

Abstract The p-p differential cross sections at 5, 7 and 8 MeV have been measured with accuracies of ± 0.3 % relative and ± 0.4% absolute. The central P-wave phase-shift combination, 3 Δ c , and the S-wave phase shifts have been determined by a phase-shift analysis of these data and compared with other analyses.

Elastic scattering of 56 MeV polarized deuterons on 4He

Abstract The differential cross section and the vector and tensor analyzing powers A y , A xx , A yy and A xz were measured for the d- 4 He elastic scattering at 56 MeV. The measurement of A xz was performed using a deuteron beam polarized in the horizontal plane. An optical-model analysis of the experimental data was carried out. The magnitude of the tensor analyzing powers could not be reproduced without the tensor potential. By including the T R type tensor potential, the optical-model calculations give a reasonable reproduction of the experimental data at θ c.m. T R tensor potential was much stronger than that predicted by the folding model. The strength of the real T R potential was roughly in accordance with that obtained from the optical-model analysis of d- 4 He elastic scattering at 20.2 MeV.

Polarization effects in the QFS region of the p-d breakup reaction at 65 MeV

Abstract The angular distributions of the analyzing power have been measured at 65 MeV in the p-p and p-n quasi-free-scattering (QFS) regions of the 2H( p , 2p)n and 2H( p , pn)p reactions, respectively, under kinematically complete conditions. The data are compared with the plane-wave-impulse-approximation calculations and the first-order calculations of the AGS equations. The results indicate that polarization effects of a “spectator” nucleon in p-p QFS are quite different from p-n QFS. The off-shell effects of the “spectator” nucleon on the analyzing power are discussed.

Acceleration of protons and deuterons polarized in the horizontal plane by the RCNP cyclotron

Abstract Polarized protons and deuterons with their spin alignment axis in the horizontal plane were successfully accelerated by the RCNP cyclotron. The acceleration of the pulsed ion beam enabled us to distinguish the turn numbers of the extracted ions and to determine the spin precession angle for each turn. This technique, the Polarization Tagging Method, can be used in order to measure the rotation parameters for protons and the tensor analyzing powers for deuterons. The tensor analyzing power Axz was measured for the elastic scattering of the polarized deuterons from 1H at 56 MeV.

Measurement of Axx and Ayy for elastic scattering of 56 MeV deuterons from 28Si, 64Ni and 144Sm

The differential cross sections σ and vector and tensor analyzing powers Ay, Axx and Ayy were measured for the elastic scattering of 56 MeV polarized deuterons from 28Si, 64Ni, and 144Sm. The optical model analysis including tensor potential was performed. The well depths of the TR potential were determined from the analysis of the quantity (2Axx+Ayy)√3.