M. Romano

The Italian AMS program: Measurements with the Naples TTT-3 tandem accelerator

Abstract The HVEC model TTT-3 tandem accelerator at the University of Naples has been modified for high energy mass spectrometry measurements. The new injector includes an ANIS sputter source and a 35° inflection magnet, both manufactured by Danfysik. A switching magnet was also added to the beam transport system and the final detector was mounted on the 30° beam line dedicated to AMS. Preliminary measurements and limits of the present system are discussed.

Proton resonant and direct capture on 28Si

Abstract Excitation functions for the 28 Si(p, γ) 29 P capture reaction have been measured in the proton energy range E p = 1.3–2.3 mMeV. The analysis of the data reveals the presence of the direct capture process to the ground state and first excited state of 29 P. The strengths of the resonances at E p = 1.65, 2.09 and 2.88 MeV and the spectroscopic factors of the ground state and first excited state in 29 P are deduced.

AMS at the TTT-3 tandem accelerator in Naples

Abstract The Italian AMS facility, based on the TTT-3 tandem accelerator of the University of Naples, is now becoming operational for routine 14C measurements. The present configuration of the system and the first results obtained are discussed together with the improvements planned for the near future.

Proton direct capture on 40Ca

Abstract Excitation functions for the 40Ca(p, γ)41Sc reaction have been measured at 0° and 90° in the proton energy range Ep = 2.1–3.1 MeV. The experimental results have been interpreted in terms of the direct capture process to the first excited state of 41Sc. The direct capture transition to the ground state has been observed only at a few proton energies. The spectroscopic factor of the first excited state in 41Sc has been found to be 1.0 ± 0.3. The direct capture cross section to the ground state is consistent with the spectroscopic factor reported from stripping reactions.

A three-stage detector for heavy fragments and light particles emitted in heavy ion collisions

Abstract A low threshold charged particle three-stage detector has been designed, built and successfully tested. A truncated pyramidal geometry has been chosen to use the device as an element in a large solid angle array for heavy ion nuclear experiments. Angular resolution of 0.4° at 35 cm from the target, energy resolution of about 1% for the elastically scattered ions and Z resolving power of 63 for Z = 17 have been achieved in the 35 Cl+ 64 Ni reaction at 280 MeV incident energy.

Reaction mechanism study for the system:20Ne+60Ni at 44 MeV/A

SummaryParticle-γ coincidence measurements were carried out for the system20Ne+60Ni at 44 MeV/A. Discrete lines in the coincidence and singles γ-ray spectra were attributed to transitions between low-spin levels of residual nuclei with masses between A = 46 and A = 60. The associated particle multiplicities were found to increase with decreasing mass number. The results are discussed in the framework of a « participant-spectator » model for the reaction mechanism.

On the lifetime of the 1.701 MeV level in18F

SummaryThe lifetime of the 1.701 MeV level in18F has been measured with the DSAM by means of the inverse3He(18O, p) reaction at 15, 18 and 21 MeV incident energy, on Ta and Al backings. Dependence of the extracted values on incident energy and stopping material has been found. It is shown that both effects can be explained as due to cascade feeding from higher levels.

Lifetimes in 18 F

SummaryThe lifetimes of nine levels in18F have been measured by using the DSAM and the3He(16O, p)18F inverse reaction at 21 MeV incident energy on Al backings. Particle-gamma coincidence was employed. Levels (MeV) and corresponding lifetime (ps) deduced by a line shape analysis are as follows: 1.70 (0.897±0.057), 2.10 (4.93±0.78), 2.52 (0.554±0.045), 3.06 (<0.004), 3.13 (0.343±0.022), 3.36 (0.451±0.034), 3.72 (<0.007), 3.79 (1.90±0.20) and 3.84 (0.021±0.004).

He3(alpha,gamma)Be7 cross section at low energies

The flux of 7Be and 8B neutrinos from the Sun and the production of 7Li via primordial nucleosynthesis depend on the rate of the 3He(alpha,gamma)7Be reaction. In extension of a previous study showing cross section data at 127 - 167 keV center of mass energy, the present work reports on a measurement of the 3He(alpha,gamma)7Be cross section at 106 keV performed at Italys Gran Sasso underground laboratory by the activation method. This energy is closer to the solar Gamow energy than ever reached before. The result is sigma = 0.567 +- 0.029(stat) +- 0.016(syst) nbarn. The data are compared with previous activation studies at high energy, and a recommended S(0) value for all 3He(alpha,gamma)7Be activation studies, including the present work, is given.

Gamma-ray spectroscopy with incomplete fusion reactions for the systems 16O +58,64Ni at 100 Me V

Abstract Energy spectra and angular distributions of ejectiles with 3 ⩽ Z ⩽ 7 have been measured for the reaction 16 O on 64 Ni at 100MeV incident energy. Measured optimum Q -values and cross sections are accounted for by an incomplete fusion model. Coincidences between ejectiles detected at grazing angle and discrete γ-rays have been measured for the reactions 100 MeV 16 O+ 58,64 Ni. The in-plane to out-of-plane anisotropies of discrete γ-rays show a high degree of spin polarization of incomplete fusion residues which can be exploited for spectroscopic studies.