H. Takai

Low-lying states in /sup 111/In

Nuclear levels in /sup 111/In have been investigated by means of the /sup 110/Cd(/sup 3/He,d)/sup 111/In reaction at an incident energy of 22.5 MeV. The outgoing deuterons were analyzed by a magnetic spectrograph and a resolution of 16 keV was achieved. A total of 34 levels, up to 3.3 MeV excitation, were observed, 25 of them previously unknown. A distorted-wave Born approximation analysis has been performed to assign angular momentum transfers to the transitions and to determine spectroscopic factors for the residual states. Total spin assignments have tentatively been made with the help of shell-model predictions. The results are compared to previous experimental data and to nuclear structure calculations on the odd indium isotopes.

Phenomenological analysis of /sup 10/B+/sup 16/O elastic scattering

Angular distributions for the elastic scattering of /sup 16/O from /sup 10/B have been measured at E/sub c.m./ = 14.17, 16.15, and 18.65 MeV over an angular range from 20/sup 0/ to 176/sup 0/. The angular distributions, which exhibit an oscillatory enhancement of the cross section at backward angles, are described by a scattering matrix parametrization, by adding a very narrow l window to the normal, strong absorption S matrix.

A single-wire proportional counter with delay-line position readout for the focal plane of a magnetic spectrograph

Abstract A 38 cm position sensitive gas counter has been developed for use with an Enge split-pole spectrograph. The detector is basically a combination of a drift chamber and a proportional counter with a cylindrical delay line located parallel to the anode were providing the position information. The proportional counter provides also information on the energy deposited in the drift space by the passing particle. An intrinsic position resolution of ∼ 0.3 mm is deduced from tests with alpha-particles from a 241Am source normally incident upon the detector. Spectrograph results for a solid angle of 2.68 msr and for ≥ 2 particles incident at 45° show total resolutions of ∼ 0.75 mm. Particle identification and background suppression with the † E signal are analyzed.

Compression, Expansion, and Freeze-Out in Nucleus-Nucleus Collisions at the AGS

In the following we will present selected aspects of recent data on central nucleus-nucleus collisions taken by the E814/E877 collaboration at the BNL-AGS. We will first demonstrate that stopping is nearly complete in these collisions, and discuss the initial energy and baryon densities inferred from model comparisons with the data. Next we will discuss the amount of expansion the system undergoes from the initial phase until freeze-out by presenting recent results on pion-pion correlations. The (baryonic) resonance composition of the system at freeze-out is obtained by analyzing pion spectra at low transverse momentum P t and by inspection of direct measurements of the ∆(1232) resonance. Based on analysis of these measurements we will then discuss a “local” freeze-out scenario, where the freeze-out volume is connected with the temperature averaged pion-nucleon cross section. A summary of the current results and of future plans for Au-Au collisions with the E877 apparatus concludes the paper.