Search results for "nuclear reaction"

Asymmetries in elastic scattering of 100 MeVπ+from a polarizedHe3target

1991

We report the observation of a large asymmetry in the elastic scattering of 100 MeV {pi}{sup +} from a polarized {sup 3}He target. Measurements have been made at laboratory angles of 60{degree}, 80{degree}, and 100{degree}, with the largest value {ital A}{sub {ital y}}=0.89{plus minus}0.12 occurring at 80{degree}, near a cross-section minimum. This asymmetry is the largest observed to date in pion scattering from a spin-1/2 nucleus. The {ital A}{sub {ital y}} data are qualitatively reproduced by a schematic model; however, agreement with the data is significantly improved when realistic three-body Faddeev wave functions and a full nonlocal distorted-wave impulse approximation reaction model…

Elastic and inelastic LSP-nucleus scattering on medium-heavy nuclei

2010

Elastic and inelastic scattering rates of the lightest supersymmetric particle (LSP) off nuclei are derived for the stable iodine, xenon and cesium detectors. The parameters of the supersymmetric theory are decoupled from the nuclear structure. The involved nuclear wave functions are calculated in the nuclear shell model by using a realistic effective two-nucleon interaction in a realistic valence space. By using fitted nuclear gyromagnetic factors we successfully reproduce the relevant spectroscopic data in the discussed nuclei.

Resonant formation of pionic atoms with neutron collisions

1992

We study the {ital n}+{ital A}{r arrow}({ital A}{prime}{pi}{sub {ital b}}{sup {minus}}){r arrow}{ital n}+{ital A} reaction, or resonant formation of pionic atoms, with neutron scattering. We evaluate the contribution of the interference of this reaction channel in {sup 40}Ca and {sup 208}Pb to the elastic scattering amplitude at backward angles. The ratio of signal to the background at 80{degree} is about 10{sup {minus}3}, and we estimate that the ratio does not improve at higher angles, hence making this reaction impractical. Our findings have repercussions on a similar reaction now running at the Indiana University Cyclotron Facility.

Nuclear reactions in collisions of very heavy ions at energies below and near the barrier

2008

Modeling moderated proportional neutron counters using the Geant4 toolkit and the application to detection of fast neutron burst

2014

Scattering of Strongly Interacting Particles on Nuclei

1996

This chapter deals with the interaction of strongly interacting particles (hadrons) with nuclei, at low and intermediate energies. The hadronic projectiles are used as probes of nuclear properties and of the hadron-nucleon interaction in the nuclear medium, and they are selected accordingly. We discuss mainly the case of pions, to some extent also kaons, because of the specific properties of the pion-(kaon)-nucleon system. Some of the methods and results can also be applied to nucleons if these are chosen to be projectiles, but we do not go into the full complexity of the spin analysis of the nucleon-nucleon system. In this sense this field is distinct from the conventional topic of nuclear…

The Beta-Delayed Proton and Gamma Decay of 27P for Nuclear Astrophysics

2013

The creation site of 26Al is still under debate. It is thought to be produced in hydrogen burning and in explosive helium burning in novae and supernovae, and possibly also in the H-burning in outer shells of red giant stars. Also, the reactions for its creation or destruction are not completely known. When 26Al is created in novae, the reaction chain is: 24Mg(p,γ)25AI(β+v)25 Mg(p,γ)26Al, but this chain can be by-passed by another chain, 25Al(p, γ)26Si(p, γ)27P and it can also be destroyed directly. The reaction 26m Al (p, γ)27 Si* is another avenue to bypass the production of 26Al and it is dominated by resonant capture. We find and study these resonances by an indirect method, through the…

Nuclear Ground-State Properties from Laser and Mass Spectroscopy

1990

Atomic physics played an important role in establishing our present-day knowledge on the atomic nucleus. Especially mass spectrometry and optical spectroscopy were the main sources of information on nuclear properties in the early days of nuclear physics. Still now, precise information on nuclear masses (or binding energies) are obtained by mass spectrometry whereas mass differences between two isotopes are usually determined by nuclear-spectroscopy techniques via a determination of the Q-value of nuclear reactions or decay. Almost all our information on the nuclear spins I, the nuclear magnetic dipole moment μ I, the spectroscopic quadrupole moment Q, and the changes in the mean-square cha…

Precision Spectroscopy on Trapped Radioactive Ions: Ground-State Hyperfine Splittings of 133 Ba + and 131 Ba +

1987

The ground-state hyperfine splitting of radioactive Ba+ isotopes of mass 133 and 131, confined in a r.f. quadrupole trap, has been measured by laser-microwave double resonances. The results are Δν(133) = 9 925 453 554.59(10) Hz and Δν(131) = 9 107 913 698.97 (50) Hz. The experiment, including measurements of systematic shifts, was performed on quantities of about 1012 isotopes, produced by nuclear reactions and collected at the ISOLDE facility at CERN. The precision is comparable to equivalent measurements on stable isotopes and demonstrates the high-sensitivity of the stored-ion technique. The experiment can be regarded as a first step to a systematic precision study of hyperfine anomalies…

The limits of the nuclear landscape

2012

In 2011, 100 new nuclides were discovered. They joined the approximately 3,000 stable and radioactive nuclides that either occur naturally on Earth or are synthesized in the laboratory. Every atomic nucleus, characterized by a specific number of protons and neutrons, occupies a spot on the chart of nuclides, which is bounded by 'drip lines' indicating the values of neutron and proton number at which nuclear binding ends. The placement of the neutron drip line for the heavier elements is based on theoretical predictions using extreme extrapolations, and so is uncertain. However, it is not known how uncertain it is or how many protons and neutrons can be bound in a nucleus. Here we estimate t…