Search results for "Ground state"
showing 10 items of 928 documents
Properties ofNe22(α,n)25Mg resonances
1991
The $^{22}\mathrm{Ne}$(\ensuremath{\alpha},n${)}^{25}$Mg reaction has been investigated in the energy range ${\mathit{E}}_{\mathrm{\ensuremath{\alpha}}}^{\mathrm{lab}}$=0.73--2.10 MeV using high-resolution $^{3}\mathrm{He}$ ionization chambers. Sixteen resonances have been observed in the three neutron channels to the ground state and the first two excited levels of $^{25}\mathrm{Mg}$. From the analysis of neutron angular distributions, spin and parity assignments could be made for eight resonances. Furthermore, partial widths as well as absolute cross sections have been obtained yielding resonance strengths for the observed levels. The role of the $^{22}\mathrm{Ne}$(\ensuremath{\alpha},n) …
The decay of105Tc to levels in105Ru
1975
Theβ−-decay of 7.6-min105Tc has been investigated byβ- andγ-ray singles and coincidence measurements. The activities have been produced by thermal-neutron-induced fission of235U or239Pu and subsequent chemical separation of the technetium fraction from the fission product mixture. AQβ-value of 3.2±0.2 MeV has been determined. In a delayed coincidence experiment the lifetime of the first excited state in105Ru at 20.55 keV has been measured to be 340±15 nsec. A level scheme of105Ru is proposed and compared with the results of recent nuclear reaction studies like104Ru(d, p) and104Ru(n, γ). From beta branching ratios to levels in105Ru, ground state spin and parity of 5/2+ can be suggested for10…
Shape coexistence at the proton drip-line: First identification of excited states inPb180
2010
Excited states in the extremely neutron-deficient nucleus {sup 180}Pb have been identified for the first time using the JUROGAM II array in conjunction with the RITU recoil separator at the Accelerator Laboratory of the University of Jyvaeskylae. This study lies at the limit of what is presently achievable with in-beam spectroscopy, with an estimated cross section of only 10 nb for the {sup 92}Mo({sup 90}Zr,2n){sup 180}Pb reaction. A continuation of the trend observed in {sup 182}Pb and {sup 184}Pb is seen, where the prolate minimum continues to rise beyond the N=104 midshell with respect to the spherical ground state. Beyond-mean-field calculations are in reasonable correspondence with the…
Mass and low-lying levels ofIn106,108from theCd106,108(p,nγ)reactions
1984
106In has been studied via the reaction 106Cd(p,nγ)106In in the energy range Ep=7-9 MeV. Inbeam γ-ray excitation functions, γ-γ coincidence measurements, and β+-delayed γ-ray excitation functions have been used to identify thirteen levels in 106In. From this new level scheme the energy separation of the high-spin ground state and the low-spin isomer has been determined to be 28.6±0.5 keV. The threshold energy of the strongest low-lying γ-ray transition yields a mass excess for 106In of -80601±15 keV. Spins for some states are suggested by comparing the excitation functions to Hauser-Feshbach calculations. In-beam γ-ray excitation functions for the 108Cd(p,nγ)108In reaction give a mass exces…
Energy dependence of the $^{28}$Si($^{32}$S,$^{36}$Ar)$^{24}$Mg reaction between 90 and 103 MeV incident energy
1986
Abstract Angular distributions for the 28 Si( 32 S, 36 Ar) 24 Mg reaction have been measured from 90 to 103 MeV of incident lab energy, in steps of 0.5 MeV. The ground state, the 2 1 + level in each nucleus and the mutual excitation of both 2 1 + states have been resolved. The data have been analysed in the frame of finite range DWBA calculations. The deduced relative spectroscopic factors show good agreement with those predicted by the model of Chung and Wildenthal but are smaller than those deduced in other experiments.
Search for a 2-quasiparticle high-Kisomer inRf256
2011
The energies of 2-quasiparticle (2-qp) states in heavy shell-stabilized nuclei provide information on the single-particle states that are responsible for the stability of superheavy nuclei. We have calculated the energies of 2-qp states in {sup 256}Rf, which suggest that a long-lived, low-energy 8{sup -} isomer should exist. A search was conducted for this isomer through a calorimetric conversion electron signal, sandwiched in time between implantation of a {sup 256}Rf nucleus and its fission decay, all within the same pixel of a double-sided Si strip detector. A 17(5)-{mu}s isomer was identified. However, its low population, {approx}5(2)% that of the ground state instead of the expected {a…
Quantum annealing with manufactured spins.
2011
Many interesting but practically intractable problems can be reduced to that of finding the ground state of a system of interacting spins. It is believed that the ground state of some naturally occurring spin systems can be effectively attained through a process called quantum annealing. Johnson et al. use quantum annealing to find the ground state of an artificial Ising spin system comprised of an array of eight superconducting flux qubits with programmable spin–spin couplings. With an increased number of spins, the system may provide a practical physical means to implement quantum algorithms, possibly enabling more effective approaches towards solving certain classes of hard combinatorial…
Engineering NonBinary Rydberg Interactions via Phonons in an Optical Lattice
2019
Coupling electronic and vibrational degrees of freedom of Rydberg atoms held in optical tweezer arrays offers a flexible mechanism for creating and controlling atom-atom interactions. We find that the state-dependent coupling between Rydberg atoms and local oscillator modes gives rise to two- and three-body interactions which are controllable through the strength of the local confinement. This approach even permits the cancellation of two-body terms such that three-body interactions become dominant. We analyze the structure of these interactions on two-dimensional bipartite lattice geometries and explore the impact of three-body interactions on system ground state on a square lattice. Focus…
Precision measurement of spin-dependent interaction strengths for spin-1 and spin-2 87Rb atoms
2006
We report on precision measurements of spin-dependent interaction-strengths in the 87Rb spin-1 and spin-2 hyperfine ground states. Our method is based on the recent observation of coherence in the collisionally driven spin-dynamics of ultracold atom pairs trapped in optical lattices. Analysis of the Rabi-type oscillations between two spin states of an atom pair allows a direct determination of the coupling parameters in the interaction hamiltonian. We deduce differences in scattering lengths from our data that can directly be compared to theoretical predictions in order to test interatomic potentials. Our measurements agree with the predictions within 20%. The knowledge of these coupling pa…
Nuclear ground state properties of 99Sr by collinear laser spectroscopy with non-optical detection
1991
Abstract Collinear fast-beam laser spectroscopy, with improved sensitivity for ions with hyperfine split transitions, is performed to measure the hyperfine structure and the isotope shift of the well deformed short-lived 99Sr. The new method consists in ground state depopulation by a two-step optical pumping sequence prior to state selective neutralization and fast-atom counting. A definitive nuclear spin value I = 3 2 , the change in mean square charge radius δ〈r2〉98,99 and the nuclear moments are derived. These results are compared to nuclear spectroscopy information and are interpreted in the frame of the particle plus deformed core model.