R. Abegg

The reaction 2H(p,π+)3H at 470 and 500 MeV

Abstract Angular distributions of the cross section at 470 and 500 MeV and the analyzing power at 500 MeV incident proton energy are presented for the reaction 2 H ( p ,π + ) 3 H . The cross section and analyzing power measurements cover the respective angular ranges 10°

Investigation of microscopic form factors for the (p, α) reaction☆

Abstract Microscopic form factors for the three-nucleon transfer (p, α) reaction are described, with special emphasis on their comparison with conventional cluster form factors. Considerable differences in shape of these form factors is found, especially in the surface region. An extension of the earlier zero-range descriptions of the microscopic form factor to include finite-range effects, is formulated and tested. Center of mass corrections, the α-particle size parameter, and non-local corrections in the single-particle states, all have a strong influence on the shape of the microscopic form factor. The implications of these observations for the extraction of nuclear structure information is discussed, especially as this affects the commonly used procedure of replacing the microscopic form factor with a cluster form factor, in the actual DWBA calculation.

PROTON LOSS BY NUCLEAR INELASTIC INTERACTIONS IN GERMANIUM

Abstract The probability of protons undergoing nuclear inelastic interactions while stopping in germanium has been measured in a direct counting experiment using protons with energies between 25 and 49 MeV incident on a germanium detector. These values have been determined to an accuracy of approximately ±2%. Calculations of the proton reaction probability over the incident energy range 20–150 MeV have also been made, using previously reported proton total reaction cross sections. The experimental and calculated results agree to within ±1.8%.

Measurement of the proton total reaction cross section for 159Tb, 181Ta and 197Au between 20 and 48 MeV

Abstract Proton total reaction cross sections have been measured for the nuclei 159 Tb, 181 Ta and 197 Au at seven proton energies between 20 and 48 MeV using an attenuation technique. The experimentally determined energy dependence of the total reaction cross sections is compared with results obtained for black nucleus and optical model calculations.

A liquid 3He target system for use at intermediate energies

Abstract A liquid 3 He target system, with remote instrumentation and handling capabilities, has been developed for experiments using the 180–525 MeV TRIUMF cyclotron. 3 He gas is liquified, by means of a 4 He cryostat, into a cylindrical target cell (4.4 cm diameter, 1.6 cm thick) and maintained during operation at ∼1.6 K. This provides an areal target density of ∼2.7×10 22 3 He nuclei/cm 2 (128 mg/cm 2 ), suitable for intermediate energy proton scattering.

The 18O(p, α)15N reaction at 40.9 MeV☆

Abstract The 18 O(p, α) 15 N reaction has been studied at a proton energy of 40.9 MeV with an overall energy resolution of about 100keV. Differential cross sections for levels with excitation energies up to about 12 MeV were measured. Finite-range DWBA calculations were performed using cluster form factors, and the deduced spectroscopic factors compared with the shell-model calculations of Millener. Numerous states show considerably greater strength than predicted by the shell model.

Zero‐crossing angle of the np analyzing power below 300 MeV

The zero point of the analyzing power for neutron‐proton scattering has been measured as a function of scattering angle for 4 incident neutron energies, 174.3, 202.4, 216.5, and 260.3 MeV. The accuracy is ±0.25°. (AIP)

Measurement of the depolarization parameter D in elastic 9Be(p,p) scattering

The depolarization parameter D has been measured for the 9Be(p,p) reaction at 225 MeV bombarding energy, for the laboratory angles of 22.4°, 30°, 40°, and 50°. The results show that D deviates from unity, and hence demonstrate the need for a spin‐spin term in the optical potential.

Search for the dibaryon bandhead

Analyzing power measurements were obtained for the reaction 2H(p↘,p1) at Tp=500 MeV using the 1.6 GeV/c TRIUMF magnetic spectrometer in an attempt to find evidence for the possible existence of the ppπ bandhead of the dibaryon system. Coincidence measurements of Ay at θlab=25°, 30° and 35° did not reveal any evidence for the existance of the ppπ bandhead in this initial experiment.