Search results for "Spins"
showing 10 items of 257 documents
Collinear laser spectroscopy on unstable isotopes—A tool of nuclear physics
1985
Atomic hyperfine structures and isotope shifts yield basic information about nuclear ground-state spins, moments and mean square charge radii. Recently, the collinear-beam laser experiments at ISOLDE have considerably enlarged the range of elements for which these studies can be extended into regions far from β-stability. The essential features of these experiments are outlined, and examples of the results on the rare-earth and radium isotopic chains are given. Finally, further improvements in sensitivity using non-optical detection are discussed.
Simple modeling of dipolar coupled 7Li spins and stimulated-echo spectroscopy of single-crystalline β-eucryptite
2004
Abstract Stimulated-echo spectroscopy has recently been applied to study the ultra-slow dynamics of nuclear spin-3/2 probes such as 7 Li and 9 Be in solids. Apart from the dominant first-order quadrupolar interaction in the present article also the impact of the homonuclear dipolar interactions is considered in a simple way: the time evolution of a dipole coupled pair of spins with I =3/2 is calculated in an approximation, which takes into account that the satellite transitions usually do not overlap. Explicit analytical expressions describing various aspects of a coupled quadrupolar pair subjected to a Jeener–Broekaert pulse sequence are derived. Extensions to larger spin systems are also …
Lasers at accelerators: past, present and future
1992
The application of lasers at accelerators is reviewed with emphasis on laser spectroscopy of short-lived isotopes and the determination of nuclear spins, moments, and changes of charge radii in long isotopic chains leading far-off stability. Experimental techniques as well as future directions are discussed.
Nuclear moments from laser spectroscopy
1988
The systematic laser spectroscopy measurements of nuclear spins, moments and charge radii from hyperfine structures and isotope shifts are reviewed from a methodical point of view. Examples are given for the typical experimental approaches and their results. Laser spectroscopy methods of direct nuclear g-factor measurement have interesting features in common with the low-temperature nuclear orientation technique. These are described in some detail and discussed in their particular physics context.
Low-lying levels of 188Re nucleus from γγ-coincidence measurements
2010
Low–high and low–low energy γγ-coincidences, following the Re187(n,γ)Re188 reaction with thermal neutrons, have been measured. Spectra have been recorded in the energy range from 50 to 2600 keV, and from 4500 to 6500 keV. The earlier known 188Re level scheme is corrected and extended up to ∼800 keV excitation energy and 62 levels by including 20 new levels. For 11 levels, the earlier interpretation has been changed. The complete level scheme is presented for up to ∼400 keV energy and spins ⩽5. Core plus two-quasiparticles model calculations have been performed. Some 188Re two-quasiparticle states display features indicating the nuclear shape phase transition from axial-deformation to γ-soft…
Two- and three-body correlations: breakup of halo nuclei
2004
4 pages, 2 figures.
Nuclear Radii and Moments of Unstable Isotopes
1989
The development of on-line mass separators, which provide long chains of isotopes extending far off stability, immediately raised the question of how to gain access to the basic nuclear ground-state properties of these exotic nuclei—their spins, moments, radii, and masses. In general, the amount of radioactive material produced at these facilities is too small to form beams or targets for any kind of scattering or nuclear-reaction experiment. On the other hand, the traditional spectroscopic methods, namely, atomic, nuclear, and mass spectroscopy, have turned out to be very suitable for this application since they are easily adapted to the special on-line conditions.
Study of high spins in $^{173}$Os
1991
High-spin states in 173Os have been studied by γγ-coincidence measurements following the 146Nd(32S, 5n)173Os reaction. Additional information has also been extracted from the reaction 144Sm(32S, 2pn)173Os. Four main sequencies have been identified as the two signature branches of the bands built on the [642]52+ and [523]52− Nilsson states. The band features have been analysed within the framework of the cranked shell model. The positive-parity band provides evidence for a v(i132)2 crossing at low frequency and a π(h112)2 and/or π(h92)2 cross In the negative-parity band the upbend starts at relatively low frequency indicating, presumably, an early v(i132)2 alignment. There is evidence for an…
Prolate-oblate shape coexistence in Kr-75
1998
Abstract The collective bands of 75Kr were extended up to spin 45 2 using the compound reactions 50Cr(28Si,2pn), 54Fe(24Mg,2pn) and 58Ni(20Ne,2pn)75Kr. Lifetimes were measured by RDDS with nine OSIRIS detectors in coincidence. Mixing ratios were determined by measurements of internal conversion coefficients, angular distribution and correlations. Deviations between different measurements are explained by the short lifetimes leading to angle dependent intensity losses due to Doppler shift. Spins and parities were assigned from angular distributions, excitation functions and DCO ratios measured with the OSIRIS_12 spectrometer. The band head spin of the negative parity yrast band was establish…
High-spin study of neutron-deficient $^{114}$Xe
2000
Abstract High-spin states have been populated in 114 54 Xe via the 58 Ni( 58 Ni, 2p) reaction at 210 MeV, using the Jurosphere γ -ray spectrometer to record γ -ray coincidences. The known level scheme has been significantly extended and includes two positive-parity and three negative-parity structures. At the highest spins, one of the negative-parity bands becomes yrast and shows the characteristics of a smoothly terminating band. Quadrupole moments for two of the bands at high spin have been estimated through a Doppler-broadened lineshape analysis; the terminating band has a reduced quadrupole moment implying that it is not far from full termination into a noncollective oblate state. Extra…