Search results for "ISOTOPES"
showing 10 items of 1216 documents
Investigation of beta strength functions by neutron and gamma-ray spectroscopy
1979
Abstract Neutron spectra from the decay of the β− delayed neutron precursors 55.6 sec 87Br, 24.5 sec 137I, 2.05 sec 85As and 1.71 sec 135Sb have been studied with high resolution 3He ionization chambers. By γ-ray measurements, the partial neutron emission probabilities to excited states in 84Se and 134Te have been determined independently. For the neutron-emitter nuclei 87Kr and 137Xe, from which neutron decay proceeds only to the ground states of the final nuclei, 86Kr and 136Xe, unique information on the shape of the β− strength function Sβ(E) is obtained. For the emitter nuclei 85Se and 135Te, correlations between neutron transition energies and differences in level energies in 84Se and …
Radioactivity of neutron-rich oxygen fluorine and neon isotopes
1999
The $\ensuremath{\gamma}$ radiation and neutrons emitted following the $\ensuremath{\beta}$ decays of ${}^{24}\mathrm{O},$ ${}^{25--27}\mathrm{F},$ and ${}^{28\ensuremath{-}30}\mathrm{Ne}$ have been measured. The nuclides were produced in the quasifragmentation of a 2.8 GeV ${}^{36}\mathrm{S}$ beam, separated in-flight and identified through time-of-flight and energy-loss measurements. The ions were stopped in a silicon detector telescope, which was used to detect the $\ensuremath{\beta}$ particles emitted in their subsequent radioactive decay. The coincident $\ensuremath{\gamma}$ rays were measured using four large volume germanium detectors mounted close to the implantation point and the …
First observation of β decay ofNb108toMo108
1996
The \ensuremath{\beta}-delayed \ensuremath{\gamma} decay of $^{108}\mathrm{Nb}$ has been studied using the on-line mass-separator technique. The measured \ensuremath{\beta}-decay half-life 0.20\ifmmode\pm\else\textpm\fi{}0.03 s agrees with the previous measurement based on \ensuremath{\beta}-delayed neutron detection. The lifetime of the first ${2}^{+}$ state in $^{108}\mathrm{Mo}$ was measured to be 0.5\ifmmode\pm\else\textpm\fi{}0.3 ns, which is consistent with a deformation \ensuremath{\beta}\ensuremath{\approxeq}0.4. Spin and parity of ${2}^{+}$ are suggested for the ground state of $^{108}\mathrm{Nb}$. \textcopyright{} 1996 The American Physical Society.
Collective structure of the neutron-rich nuclei, 110Ru and 112Ru
1990
Abstract The collective structure of 110 Ru and 112 Ru has been studied at the IGISOL facility through the beta decay of 110 Tc and 112 Tc. Neutron-rich technetium isotopes were produced by the 238 U(p, f) reaction at 20 MeV bombarding energy. The new isotope 112 Tc was found to decay with a half-life of 280(30) ms. The observed energies of the 2 + and 4 + ground state band levels in 108,110,112 Ru are almost the same. However, a steady energy decrease of the proposed gamma band head is observed with increasing neutron number, suggesting importance of triaxiality in these nuclei. In fact, only in 192 Os the second 2 + state has been observed at lower excitation than in 112 Ru. The static de…
Identification of yrast high-Kintrinsic states inOs188
2009
The high-spin structure of the $Z=76$ nucleus $^{188}\mathrm{Os}$ has been studied using the incomplete fusion reaction $^{7}\mathrm{Li}+^{186}\mathrm{W}$. A ${K}^{\ensuremath{\pi}}={10}^{+}$ band has been established up to spin $({24}^{+})$ and its crossing with the ground-state band has been studied. In addition, intrinsic high-$K$ states have been identified and on top of two of them, ${K}^{\ensuremath{\pi}}={7}^{\ensuremath{-}}$ and ${K}^{\ensuremath{\pi}}={10}^{\ensuremath{-}}$, regular bands have been observed. The ${K}^{\ensuremath{\pi}}={16}^{+}$ and ${K}^{\ensuremath{\pi}}={18}^{+}$ states are yrast whereas the ${K}^{\ensuremath{\pi}}={14}^{+}$ level lies only 33 keV above the yras…
Charge radii and ground state structure of lithium isotopes: Experiment and theory reexamined
2011
Changes in the nuclear charge radii of lithium isotopes were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. We discuss the choice of the reference isotope for absolute charge radii determinations in the lithium isotopic chain and report a new value for the charge radius of ${}^{6}$Li, based on the analysis of the world scattering data. A summary of the lithium nuclear charge radii obtained in this way is presented. Additionally, new calculations in fermionic molecular dynamics for the lithium isotopes were performed. We summarize the status of the lithium nuclear charge radii, magnetic dipole and electric quadrupole moment…
Determination of the content in uranium oxide particles by fission track analysis
2004
Abstract One of the most important tasks of nuclear safeguards is to control the activities in nuclear facilities worldwide. These activities include the enrichment of 235 U . To identify enrichments above the maximum authorised level in commercial enrichment plants (usually 5% 235 U ) swipe tests are performed and the 235 U enrichment is determined in the sampled uranium oxide particles. A method is described that allows to measure the 235 U content in small particles (around 1 μm in diameter) by the use of fission tracks. It is based on the fact that in uranium fuel, only 235 U atoms are fissile with thermal neutrons and contribute to the amount of fission tracks counted for individual pa…
Optimization of krypton yields for rp-process studies at ISOLDE(CERN)
2004
The production of neutron-deficient krypton isotopes having astrophysical importance has been studied at the ISOLDE PBS facility at CERN. To investigate several effects on the yield a Monte Carlo code has been extensively applied.
QECvalues of the superallowedβemittersC10,Ar34,Ca38, andV46
2011
The ${Q}_{\mathrm{EC}}$ values of the superallowed ${\ensuremath{\beta}}^{+}$ emitters $^{10}\mathrm{C}$, $^{34}\mathrm{Ar}$, $^{38}\mathrm{Ca}$, and $^{46}\mathrm{V}$ have been measured with the JYFLTRAP Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7), and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results. Of the well-known superallowed emitters, only $^{14}\mathrm{O}$ has yet to have had its ${Q}_{\mathrm{EC}}$ value measured with a Penning trap.
Charge-radius change and nuclear moments in the heavy tin isotopes from laser spectroscopy: Charge radius ofSn132
2005
Laser spectroscopy measurements have been carried out on the neutron-rich tin isotopes with the COMPLIS experimental setup. Using the $5{s}^{2}5{p}^{2\phantom{\rule{0.3em}{0ex}}3}{P}_{0}\ensuremath{\rightarrow}5{s}^{2}5p6s\phantom{\rule{0.3em}{0ex}}{}^{3}{P}_{1}$ optical transition, hyperfine spectra of $^{126\ensuremath{-}132}\mathrm{Sn}$ and $^{125,127,129\ensuremath{-}131}\mathrm{Sn}{}^{m}$ were recorded for the first time. The nuclear moments and the mean square charge radius variation ($\ensuremath{\delta}\ensuremath{\langle}{r}_{c}^{2}\ensuremath{\rangle}$) were extracted. From the quadrupole moment values, these nuclei appear to be spherical. The magnetic moments measured are thus co…