Search results for "Ground"
showing 10 items of 2432 documents
Alpha decay of the new isotopes 188,189Po
1999
New neutron-deficient isotopes 188,189Po have been produced in the complete fusion reaction of 52Cr ions with a 142Nd target at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of α-γ and α-conversion electron coincidence measurements and of α-α position and time correlations. In 189Po a ground state to ground state α decay with Eα1= 7540(20) keV, T1/2= 5(1) ms and two fine structure α-decays at Eα2= 7264(15) keV and Eα3= 7316(15) keV have been observed. In 188Po (T1/2= 400+200 −150μs) a ground state to ground state α decay at Eα= 7915(25) keV and a fine structure α decay at Eα= 7350(40) keV have been found. Improved data o…
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…
The ASTERIX spectrometer at LEAR
1989
The ASTERIX spectrometer has been used to study the formation and the ground state of the pp atom and exclusive final states of pp annihilation at rest in a H2 gas target at NTP, using antiprotons from the Low Energy Antiproton Ring (LEAR) at CERN. The article describes the mechanical construction of the apparatus, the trigger logic, the chamber readout, and the data acquisition system. The detector calibration and the offline processing of the 55 million reconstructed events are illustrated. An overview is given about the new physics results obtained by the experiment.
ϒ production and nuclear modification at forward rapidity in Pb–Pb collisions at sNN=5.02TeV
2021
Abstract The production of ϒ mesons in Pb–Pb collisions at a centre-of-mass energy per nucleon pair s NN = 5.02 TeV is measured with the muon spectrometer of the ALICE detector at the LHC. The yields as well as the nuclear modification factors are determined in the forward rapidity region 2.5 y 4.0 , as a function of rapidity, transverse momentum and collision centrality. The results show that the production of the ϒ ( 1S ) meson is suppressed by a factor of about three with respect to the production in proton–proton collisions. For the first time, a significant signal for the ϒ ( 2S ) meson is observed at forward rapidity, indicating a suppression stronger by about a factor 2–3 with respec…
Das Vorzeichen der Hyperfeinstruktur-Aufspaltung des 3d 5 4s 2 6 S 5/2-Grundzustandes des Mn55
1962
Using a double Fabry-Perot interferometer and an atomic-beam light source, the sign of the hyperfine-structure splitting of the 3d 5 4s 2 6 S 5/2 ground state of Mn55 has been determined to be negative. The absolute value of the splitting previously has been measured byWoodgate andMartin.
Spin, moments, and mean square nuclear charge radius ofSr77
1992
The neutron deficient $^{77}\mathrm{Sr}$ nucleus was studied by fast ion beam collinear laser spectroscopy with a detection scheme based on optical pumping, state selective neutralization, and atom counting. From the measured hyperfine splitting and isotope shift of the Sr II transition 5s $^{2}$${\mathit{S}}_{1/2}$\ensuremath{\rightarrow}5p $^{2}$${\mathit{P}}_{3/2}$ the nuclear spin I=5/2, the nuclear moments \ensuremath{\mu}=-0.348(4)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$, ${\mathit{Q}}_{\mathit{s}}$=1.40(11) b, and the change in mean square charge radius \ensuremath{\delta}〈${\mathit{r}}^{2}$${\mathrm{〉}}^{88,77}$=0.248(12) ${\mathrm{fm}}^{2}$ were deduced. These ground-state proper…
Nuclear ground-state spins and magnetic moments ofMg27,Mg29, andMg31
2008
The ground-state spins and magnetic moments of neutron-rich {sup 27}Mg, {sup 29}Mg, and {sup 31}Mg were measured for the first time with laser and {beta}-NMR spectroscopy at ISOLDE/CERN. The hyperfine structure of {sup 27}Mg--observed in fluorescence--confirms previous assignments of the spin I=1/2 and reveals the magnetic moment {mu}{sub I}({sup 27}Mg)=-0.4107(15){mu}{sub N}. The hyperfine structure and nuclear magnetic resonance of optically polarized {sup 29}Mg--observed in the asymmetry of its {beta} decay after implantation in a cubic crystal--give I=3/2 and {mu}{sub I}({sup 29}Mg)=+0.9780(6){mu}{sub N}. For {sup 31}Mg they yield together I=1/2 and {mu}{sub I}({sup 31}Mg)=-0.88355(15){…
Nuclear moments and charge radii of the171Hf ground state and isomer
2000
The magnetic moment, quadrupole moment and mean-square charge radial changes, relative to 172Hf, have been measured for the 171Hf ground state and the ½-[521] isomeric state, using on-line laser spectroscopy. The magnetic moments of the isomer and ground states are found to be + 0.526(16)µn and -0.674(12)µn, respectively. The spectroscopic quadrupole moment of the ground state is found to be +3.463(27) b. No change in mean-square charge radius is observed between the ground state and isomeric state. The observation of an inversion in the odd-even staggering at 171Hf is consistent with the suggested deformation trends.
Shell structure of potassium isotopes deduced from their magnetic moments
2014
\item[Background] Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability. \item[Purpose] Extend our knowledge about the evolution of the $1/2^+$ and $3/2^+$ states for K isotopes beyond the $N = 28$ shell gap. \item[Method] High-resolution collinear laser spectroscopy on bunched atomic beams. \item[Results] From measured hyperfine structure spectra of K isotopes, nuclear spins and magnetic moments of the ground states were obtained for isotopes from $N = 19$ up to $N = 32$. In order to draw conclusions about the composition of the wave functions and the occupation of the …