502 research outputs found
Perturbed angular correlations for Gd in gadolinium: in-beam comparisons of relative magnetizations
Perturbed angular correlations were measured for Gd ions implanted into
gadolinium foils following Coulomb excitation with 40 MeV O-16 beams. A
technique for measuring the relative magnetizations of ferromagnetic gadolinium
hosts under in-beam conditions is described and discussed. The combined
electric-quadrupole and magnetic-dipole interaction is evaluated. The effect of
nuclei implanted onto damaged or non-substitutional sites is assessed, as is
the effect of misalignment between the internal hyperfine field and the
external polarizing field. Thermal effects due to beam heating are discussed.Comment: 37 pages, 15 figures, accepted for publication in NIM
Consistent description of magnetic dipole properties in transitional nuclei
It is shown that a consistent description of magnetic dipole properties in
transitional nuclei can be obtained in the interacting boson model-2 by F-spin
breaking mechanism, which is associated with differences between the proton and
neutron deformations. In particular, the long standing anomalies observed in
the -factors of the Os-Pt isotopes are resolved by a proper inclusion of
F-spin breaking.Comment: Revtex, 10 pages, 4 figures (available from authors upon request
Free-ion hyperfine fields and magnetic-moment measurements on radioactive beams
The recoil in vacuum (RIV) technique for magnetic-moment measurements on radioactive beams is discussed with examples from the 132Sn region. Attention then turns to recoil in vacuum and the free-ion hyperfine fields of Se and Ge ions leaving carbon foil
Intermediate energy Coulomb excitation as a probe of nuclear structure at radioactive beam facilities
The effects of retardation in the Coulomb excitation of radioactive nuclei in
intermediate energy collisions (Elab ~100 MeV/nucleon) are investigated. We
show that the excitation cross sections of low-lying states in 11Be,
{38,40,42}S and {44,46}Ar projectiles incident on gold and lead targets are
modified by as much as 20% due to these effects. The angular distributions of
decaying gamma-rays are also appreciably modified.Comment: 21 pages, 3 figures, Phys. Rev. C, in pres
Opportunities for managing peak train travel demand: a Melbourne pilot study
Melbourne, like many large cities around the world, experiences significant peak congestion on its public transport network. Demand for services in peak times is a key driver of investment in new rolling stock and infrastructure. A way of delaying these significant investments is to better utilize current available resources in non-peak times, by spreading out peak demand over a wider time period.This study used an online survey methodology to investigate the propensity of peak period train passengers commuting for work on Melbourne‟s Pakenham line to shift out of peak travel times to access a better price, service frequency, stopping pattern and train conditions. The main methodology was two Discrete Choice Model exercises (one morning-peak and one afternoon-peak) which systematically varied time of travel, price and service attributes to model customer behaviour under various scenarios.The results support the view that demand can be influenced by price and service attributes, and support the development of detailed business cases for reducing peak demand. Implications are discussed, as well as the challenges in converting these customer behaviour predictions into workable timetables, and in accurately costing the benefits of delays in investments in new rolling stock and infrastructure
Absorbed dose evaluation of Auger electron-emitting radionuclides: impact of input decay spectra on dose point kernels and S-values
The aim of this study was to investigate the impact of decay data provided by
the newly developed stochastic atomic relaxation model BrIccEmis on dose point
kernels (DPKs - radial dose distribution around a unit point source) and
S-values (absorbed dose per unit cumulated activity) of 14 Auger electron (AE)
emitting radionuclides, namely 67Ga, 80mBr, 89Zr, 90Nb, 99mTc, 111In, 117mSn,
119Sb, 123I, 124I, 125I, 135La, 195mPt and 201Tl. Radiation spectra were based
on the nuclear decay data from the medical internal radiation dose (MIRD)
RADTABS program and the BrIccEmis code, assuming both an isolated-atom and
condensed-phase approach. DPKs were simulated with the PENELOPE Monte Carlo
(MC) code using event-by-event electron and photon transport. S-values for
concentric spherical cells of various sizes were derived from these DPKS using
appropriate geometric reduction factors. The number of Auger and Coster-Kronig
(CK) electrons and x-ray photons released per nuclear decay (yield) from
MIRD-RADTABS were consistently higher than those calculated using BrIccEmis.
DPKs for the electron spectra from BrIccEmis were considerably different from
MIRD-RADTABS in the first few hundred nanometres from a point source where most
of the Auger electrons are stopped. S-values were, however, not significantly
impacted as the differences in DPKS in the sub-micrometre dimension were
quickly diminished in larger dimensions. Overestimation in the total AE energy
output by MIRD-RADTABS leads to higher predicted energy deposition by AE
emitting radionuclides, especially in the immediate vicinity of the decaying
radionuclides. This should be taken into account when MIRD-RADTABS data are
used to simulate biological damage at nanoscale dimensions.Comment: 27 pages, 4 figures, 3 table
Pushing the limits of excited-state g-factor measurements
Current developments in excited-state g-factor measurements are discussed with an emphasis on cases where the experimental methodology is being extended into new regimes. The transient-field technique, the recoil in vacuum method, and moment measurements with LaBr3 detectors are discussed.This research was supported in
part by the Australian Research Council grant numbers
DP140102986, DP140103317 and DP70101673. B.P.M.
T.J.G. and B.J.C. acknowledge the support of the Australian
Government Research Training Program. Support
for the Heavy Ion Accelerator Facility operations through
the Australian National Collaborative Research Infrastructure
Strategy (NCRIS) program is acknowledged
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