M. Ieiri

Mass number dependence of hexadecapole (Y42) excitation of the γ-vibrational band in proton inelastic scattering for 152⩽A⩽192

Abstract Inelastic scattering exciting the 2+ and 4+ members of the Kπ=2+ γ-vibrational band in 152, 154Sm, 160Gd, 164Dy, 166, 168Er, 176Yb, 182, 184W and 192Os has been measured with 65 MeV polarized protons. The quadrupole (Y22) and hexadecapole (Y42) transition strengths to the γ-vibrational band have been extracted systematically for the first time. They show strong mass number dependences, which are explained qualitatively by a simple geometrical picture.

Inelastic proton scattering exciting the γ-vibrational band in 168Er and the necessity of the hexadecapole degree of freedom in the γ-motion

Abstract Inelastic scattering exciting the 2 2 + and 4 2 + members of the γ -vibrational band in 168 Er has been investigated with 65 MeV polarized protons. A coupled-channel analysis has been performed assuming both the γ -vibrational model and the asymmetric-rotor model. A large hexadecapole term ( Y 42 + Y 4−2 ) in the γ -motion is necessary in order to reproduce the experimental data.

A multifoil carbon polarimeter for protons between 20 and 84 MeV

A new type of polarimeter has been built for protons between 20 and 84 MeV. It is a ray trace type with a multifoil of carbon, multiwire proportional chambers and plastic scintillators. The polarimeter distinguishes between elastic and inelastic scattering from carbon foil and has a large solid angle acceptance (∼ 470 msr) from the carbon foil. The effective analyzing power and the effective efficiency for practical use are estimated at 0.84 and 1.7 × 10−4 in the vicinity of 60 MeV, respectively. To evaluate these values, cross sections and analyzing powers for p—C elastic scattering have been measured for laboratory scattering angles between 15° and 80° at 19 energies from 21.1 to 83.8 MeV.

Measurements of Kyy at 0° for the 2H(p,n)2p reaction at 50, 65 and 80 MeV

The polarization transfer coefficients Kyy at 0° were measured for the reaction of 2H(p,n)2p at 50, 65 and 80 MeV. Obtained Kyy(0°) values are −0.27 ± 0.05, −0.31 ± 0.03 and −0.37 ± 0.04 at 50, 65 and 80 MeV, respectively. Calculations assuming the impulse approximation with recent np scattering phase shifts are in disagreement with the observed data, indicating the need for a three-body calculation.

Depolarization in p-15N elastic scattering and large tensor spin-spin interaction

Abstract We have measured the angular distribution of the depolarization parameter Kyy′ in p-15N elastic scattering at 65 MeV. The deviation of Kyy′ from unity is large and indicates the existence of a nucleon-nucleus spin-spin interaction. The DWBA analysis shows that the measured Kyy′ data imply a large contribution from the tensor part of the spin-spin potential.

A neutron polarimeter for the (p,n) reaction at Ep=50–80 MeV

A conventional type of neutron polarimeter consisting of three 12.5 × 12.5 cm cylindrical liquid scintillators and two 12.5 × 12.5 cm cylindrical plastic scintillators has been used to measure the transverse polarization transfer coefficient Kyy in the (p, n) reaction in the energy range 50 < Ep < 80 MeV. The effective analyzing powers of this polarimeter have been obtained empirically by observing neutrons from the 6Li(p, n)6Be reaction at θ = 0° and Ep = 50,65 and 80 MeV whose polarizations are deduced from the Kyy values of the 6Li(p,p′)6Be∗ (0+ reaction by utilizing the analogue relation. Observed effective analyzing powers are significantly reduced particularly at high energy, most likely due to the 12C(n,np)11B reaction process. The double scattering efficiencies are 6 × 10−4 and 3 × 10−4 with effective analyzing powers of 0.14 and 0.11 at En = 45 and 75 MeV, respectively.

Measurement of the depolarization parameter Kyy′ in p2H elastic scattering at Ep = 65 MeV

Abstract The depolarization parameter K y y ′ in the elastic scattering of 65 MeV polarized protons from deuterium has been measured using a newly designed spectrograph and a multi-foil polarimeter. The measured K y y ′ values are well reproduced by a Faddeev calculation using the NN interaction in a separable representation with a tensor force which reproduces the empirical mixing parameter of the 3 S 1  3 D 1 partial waves.