Anders Ingemarsson

Inelastic scattering of 185 MeV protons from Mg and Al

Abstract A magnetic spectrometer was used for the energy analysis of protons scattered from targets of magnesium (natural isotopic composition) and aluminium. The mean energy of the incident protons in the targets was 185 MeV. A total energy resolution of 350 keV (FWHM) was achieved, which made possible the observation of the excitation of a large number of discrete levels. Energy spectra were measured in the angular region of 4° to 40° (lab system). The results are presented partly in the form of tables giving measured excitation energies and maximum cross sections for resolved levels and partly in the form of graphs of angular distributions of the differential cross sections. A qualitative discussion of the results is given in terms of the multipolarities of the transitions involved and comparisons are made with similar results from other experiments in inelastic scattering and in a few cases with theoretical predictions.

Elastic and inelastic scattering of 178 MeV protons from 58Ni and 60Ni

Abstract The elastic and inelastic scattering of 178 MeV protons from 58Ni and 60Ni has been studied. Angular distributions were measured for the differential cross sections for elastic scattering as well as inelastic scattering from excited states below about 5 MeV, all with natural parity. For the elastic and for the inelastic scattering from the first excited state (2+ in both nuclei, the angular distributions for the polarization were also measured. The measurements extend out to c.m. angles of about 60°, corresponding to a momentum transfer of about 600 MeV/c. The elastic and inelastic scattering data were compared to the results of coupled-channel calculations in the vibrational model using a deformed spin-orbit interaction of the full Thomas form. Good agreement was found in general showing that the main features of the experimental results are well described in this model.

OPTICAL MODEL ANALYSIS OF ELASTIC PROTON SCATTERING AT 180 MeV.

Using proton scattering data at about 180 MeV sets of optical potential parameters have been determined for the nuclei 9Be, 12C, 27Al, 40Ca, 56Fe, 90Zr, 115In and 197Au. The experimental data consist of elastic scattering differential cross sections and polarizations as well as total reaction cross sections, except for 90Zr where the reaction cross section is missing. The effects of the finite angular resolution have been taken into account and are shown to be quite important for the polarization, in particular. The analyses have been performed both non-relativistically and semi-relativistically, and the differences appearing in the optical parameters are discussed.

Scattering of 185 MeV Protons from 90Zr

Differential cross sections and polarizations for elastic and inelastic scattering of 185 MeV protons from 90Zr were measured in the angular region between 6° and 40° (lab. system). Optical model analyses of the elastic scattering data were performed. A qualitative discussion of the results for the inelastic scattering is given, which is based mainly on the shapes of the angular distributions. Comparisons are made with relevant results from other experiments on inelastic scattering in 90Zr and lighter nuclei.

Optical model calculations for intermediate energy antiproton scattering

Abstract Optical-model analyses have been performed for the elastic scattering of antiprotons at 46.8 MeV from 12 C and at 180 MeV from 12 C, 40 Ca and 208 Pb. Calculations have also been performed with folded potentials and an effective antiproton-nucleon interaction has been derived. In the case of 12 C coupled channel effects due to the 2 + state at 4.43 MeV have been studied and deformation parameters in DWBA and in coupled channel calculations have been estimated for the vibrational as well as for the rotational model.

Medium-energy proton scattering from 58Ni: Experimental results and coupled-channel calculations

Abstract Angular distributions have been obtained for the differential cross section in 178 Me V elastic proton scattering from 58Ni, as well as inelastic scattering from the states at 1.45 Me V (2+) and 4.47 MeV (3−). For elastic scattering and for scattering from the 2+ state, the polarization was also measured. Together with the corresponding results at 1 GeV these experimental data were analysed in coupled-channel calculations using the partial-wave approach and with a deformed spin-orbit potential of the full Thomas form.

Some Notes on Optical Model Calculations at Medium Energies

Different methods of taking relativistic effects into account in optical model calculations using the non-relativistic Schroedinger equation are described. A simple expression is given for the effect on the optical potential of small changes in the wave number. The effects of these changes on the angular distributions calculated in DWBA or DWIA for inelastic scattering are discussed.

Proton polarization in scattering at 185 MeV from individual states of 24Mg

Abstract The polarization of 185 MeV protons elastically and inelastically (− Q = 1.37, 4.21, 6.01, 6.44, 7.60 and 8.38 MeV) scattered from magnesium has been measured in the region 7.5°–40° (lab system). The energy levels studied were selected with the aid of a magnetic spectrometer giving a total energy resolution of 0.7 MeV FWHM. The polarimeter was calibrated using published polarization data at 154 and 138 MeV. The angular distributions obtained were found to be very similar in shape and showed a first maximum for a scattering angle of about 20° and oscillations for larger scattering angles.

Elastic and inelastic scattering of 185 MeV protons from 12C

Abstract The polarization of 185 MeV protons in elastic scattering and in the excitation of the 2 + state at 4.44 MeV and the 0 + state at 7.65 MeV in 12 C has been measured in the angular region 2°–60°. Optical model calculations are performed for the elastic scattering. Angular distributions for the inelastic scattering from the 2 + state at 4.44 MeV and the 3 − state at 9.64 MeV are calculated in the distorted-wave impulse approximation (DWIA) as well as in the distorted-wave Born approximation (DWBA).

Optical Model Analysis of Proton and Deuteron Scattering and DWBA Calculations on (p,d)-Reactions at 185 MeV

Distorted-wave Born approximation (DWBA) calculations have been performed for (p,d)-reactions in 12C and 28Si induced by 185 MeV protons and the results have been compared with experimental data on differential cross sections and vector polarizations. In order to obtain a consistent set of parameters for the potential generating the distorted waves, a reanalysis has been made of experimental data from proton and deuteron elastic scattering. The effect on the results of the spin-orbit terms in the optical potentials has been studied, and it seems clear that at these intermediate energies the spin-orbit potentials are quite important e.g., in the extraction of spectroscopic factors.