134 research outputs found
Fission half-lives of super-heavy nuclei in a microscopic approach
A systematic study of 160 heavy and super-heavy nuclei is performed in the
Hartree-Fock-Bogoliubov approach with the finite range and density dependent
Gogny force with the D1S parameter set. We show calculations in several
approximations: with axially symmetric and reflexion symmetric wave functions,
with axially symmetric and non-reflexion symmetric wave functions and finally
some representative examples with triaxial wave functions are also discussed.
Relevant properties of the ground state and along the fission path are
thoroughly analyzed. Fission barriers, Q-factors and lifetimes with
respect to fission and -decay as well as other observables are
discussed. Larger configuration spaces and more general HFB wave functions as
compared to previous studies provide a very good agreement with the
experimental data.Comment: 26 pages, 15 figure
Spin photocurrents and circular photon drag effect in (110)-grown quantum well structures
We report on the study of spin photocurrents in (110)-grown quantum well
structures. Investigated effects comprise the circular photogalvanic effect and
so far not observed circular photon drag effect. The experimental data can be
described by an analytical expression derived from a phenomenological theory. A
microscopic model of the circular photon drag effect is developed demonstrating
that the generated current has spin dependent origin.Comment: 6 pages, 3 figure
Search for Fingerprints of Tetrahedral Symmetry in
Theoretical predictions suggest the presence of tetrahedral symmetry as an
explanation for the vanishing intra-band E2-transitions at the bottom of the
odd-spin negative parity band in . The present study reports on
experiment performed to address this phenomenon. It allowed to determine the
intra-band E2 transitions and branching ratios B(E2)/B(E1) of two of the
negative-parity bands in .Comment: presented by Q.T. Doan at XLII Zakopane School of Physics: Breaking
Frontiers: Submicron Structures in Physics and Biology, May 2008. 5 pages,
minor corrections. To be published in the proceeding
High-precision mass measurements for the isobaric multiplet mass equation at A=52
Masses of Co-52, (52)Com, Fe-52, Fe-52(m), and Mn-52 have been measured with the JYFLTRAP double Penning trap mass spectrometer. The isobaric multiplet mass equation for the T = 2 quintet at A = 52 has been studied employing the new mass values. No significant breakdown (beyond the 3 sigma level) of the quadratic form of the IMME was observed (chi(2)/n = 2.4). The cubic coefficient was 6.0(32) keV (chi(2)/n = 1.1). The excitation energies for the isomer and the T = 2 isobaric analog state in Co-52 have been determined to be 374(13) keV and 2922(13) keV, respectively. The measured mass values for Co-52 and (52)Com are 29(10) keV and 16(15) keV higher, respectively, than obtained in a recent storage-ring experiment, and significantly lower than predicted by extrapolations. Consequently, this has an impact on the proton separation energies for Co-52 and Ni-53 relevant for the astrophysical rapid proton capture process. The Q value for the proton decay from the 19/2(-) isomer in Co-53 has been determined with an unprecedented precision, Q(p) = 1558.8(17) keV.Peer reviewe
Breakdown of \u3cem\u3eK\u3c/em\u3e Selection in \u3csup\u3e178\u3c/sup\u3eHf
Coulomb activation of the four quasiparticle KÏ = 16+ 178Hf isomer (t 1/2 = 31 y) has led to the measurement of a set of Eλ matrix elements coupling the isomer band to the ground band. The present data combined with earlier 178Hf Coulomb excitation data have probed the K components in the wave functions and revealed the onset and saturation of K mixing in low-K bands, whereas the mixing is negligible in the high-K bands. The implications can be applied to other quadrupole-deformed nuclei
Spin Dependence of \u3cem\u3eK\u3c/em\u3e Mixing, Strong Configuration Mixing, and Electromagnetic Properties of \u3csup\u3e178\u3c/sup\u3eHf
The combined data of two Coulomb excitation experiments has verified the purely electromagnetic population of the KÏ = 4+, 6+, 8â, and 16+rotational bands in 178Hf via 2â€Îœ â€14 K-forbidden transitions, quantifying the breakdown of the K-selection rule with increasing spin in the low-K bands. The Îł -, 4+, and 6+bands were extended, and four new states in a rotational band were tentatively assigned to a previously known KÏ = 0+band. The quasiparticle structure of the 6+(t1/2= 77 ns) and 8â(t1/2= 4 s) isomer bands were evaluated, showing that the gyromagnetic ratios of the 6+ isomer band are consistent with a pure Ï 7/2+[404], Ï 5/2+[402] structure. The 8âisomer band at 1147 keV and the second 8âband at 1479 keV, thought to be predominantly Îœ 7/2-[514], Îœ 9/2+[624] and Ï 9/2-[514], Ï 7/2+[404], respectively, are mixed to a degree approaching the strongmixing limit. Based on measured (KÏ = 16+âE2âKÏ = 0+) matrix elements, it was shown that heavy-ion bombardment could depopulate the 16+isomer at the âŒ1% level, although no states were found that would mediate photodeexcitation of the isomer via low-energy x-ray absorption
Invariant-mass and [gamma]-ray spectroscopy using secondary, radioactive ion beams
Coulomb excitation of secondary beams (5 < Z < 20) at energies
around 250 .1 MeV was explored at GSI. For low-lying states, 7-ray spectroscopy
was utilized, while high-lying excitations were investigated by
means of invariant-mass spectroscopy
Technical Design Report for the PANDA Solenoid and Dipole Spectrometer Magnets
This document is the Technical Design Report covering the two large
spectrometer magnets of the PANDA detector set-up. It shows the conceptual
design of the magnets and their anticipated performance. It precedes the tender
and procurement of the magnets and, hence, is subject to possible modifications
arising during this process.Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti
Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski,
Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy),
Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy
Breakdown of K selection in Hf178
Coulomb activation of the four quasiparticle KÏ=16+ Hf178 isomer (t1/2=31y) has led to the measurement of a set of Eλ matrix elements coupling the isomer band to the ground band. The present data combined with earlier Hf178 Coulomb excitation data have probed the K components in the wave functions and revealed the onset and saturation of K mixing in low-K bands, whereas the mixing is negligible in the high-K bands. The implications can be applied to other quadrupole-deformed nuclei
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