596 research outputs found
The importance of combating malnutrition in care
Malnutrition results from a deficiency of macronutrients (energy and protein) and micronutrients (vitamins and minerals), that may impact on body composition, function and/or clinical outcomes (National Institute for Health and Care Excellence, 2006). A range of factors, including impaired food intake (seen in individuals who are anorexic or have difficulties swallowing), increased nutrient requirements (seen during infection) and/or loss of nutrients which may be present in individuals with inflammatory bowel disease, have been known to cause malnutrition (Dunne, 2009)
Precision Measurement of 11Li moments: Influence of Halo Neutrons on the 9Li Core
The electric quadrupole moment and the magnetic moment of the 11Li halo
nucleus have been measured with more than an order of magnitude higher
precision than before, |Q| = 33.3(5)mb and mu=3.6712(3)mu_N, revealing a
8.8(1.5)% increase of the quadrupole moment relative to that of 9Li. This
result is compared to various models that aim at describing the halo
properties. In the shell model an increased quadrupole moment points to a
significant occupation of the 1d orbits, whereas in a simple halo picture this
can be explained by relating the quadrupole moments of the proton distribution
to the charge radii. Advanced models so far fail to reproduce simultaneously
the trends observed in the radii and quadrupole moments of the lithium
isotopes.Comment: 4 pages, 4 figures, 1 tabl
A new beamline for laser spin-polarization at ISOLDE
A beamline dedicated to the production of laser-polarized radioactive beams
has been constructed at ISOLDE, CERN. We present here different simulations
leading to the design and construction of the setup, as well as technical
details of the full setup and examples of the achieved polarizations for
several radioisotopes. Beamline simulations show a good transmission through
the entire line, in agreement with observations. Simulations of the induced
nuclear spin-polarization as a function of atom-laser interaction length are
presented for Na, [1] and for Ar, which is studied in this
work. Adiabatic spin rotation of the spin-polarized ensemble of atoms, and how
this influences the observed nuclear ensemble polarization, are also performed
for the same nuclei. For Ar, we show that multiple-frequency pumping
enhances the ensemble polarization by a factor 1.85, in agreement with
predictions from a rate equations model.
[1] J. Phys. G: Nucl. Part. Phys./174408400
Ground-State Electromagnetic Moments of Calcium Isotopes
High-resolution bunched-beam collinear laser spectroscopy was used to measure
the optical hyperfine spectra of the Ca isotopes. The ground state
magnetic moments of Ca and quadrupole moments of Ca were
measured for the first time, and the Ca ground state spin was
determined in a model-independent way. Our results provide a critical test of
modern nuclear theories based on shell-model calculations using
phenomenological as well as microscopic interactions. The results for the
neutron-rich isotopes are in excellent agreement with predictions using
interactions derived from chiral effective field theory including three-nucleon
forces, while lighter isotopes illustrate the presence of particle-hole
excitations of the Ca core in their ground state.Comment: Accepted as a Rapid Communication in Physical Review
Isomer shift and magnetic moment of the long-lived 1/2 isomer in Zn: signature of shape coexistence near Ni
Collinear laser spectroscopy has been performed on the Zn
isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred
milliseconds half-life was confirmed, and the nuclear spins and moments of the
ground and isomeric states in Zn as well as the isomer shift were
measured. From the observed hyperfine structures, spins and
are firmly assigned to the ground and isomeric states. The magnetic moment
(Zn) = 1.1866(10) , confirms the spin-parity
with a shell-model configuration, in excellent
agreement with the prediction from large scale shell-model theories. The
magnetic moment (Zn) = 1.0180(12) supports a
positive parity for the isomer, with a wave function dominated by a 2h-1p
neutron excitation across the shell gap. The large isomer shift
reveals an increase of the intruder isomer mean square charge radius with
respect to that of the ground state:
= +0.204(6) fm, providing first evidence of shape coexistence.Comment: 5 pages, 4 figures, 1 table, Accepeted by Phys. Rev. Lett. (2016
Decay-assisted collinear resonance ionization spectroscopy: Application to neutron-deficient francium
This paper reports on the hyperfine-structure and radioactive-decay studies
of the neutron-deficient francium isotopes Fr performed with the
Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE
facility, CERN. The high resolution innate to collinear laser spectroscopy is
combined with the high efficiency of ion detection to provide a
highly-sensitive technique to probe the hyperfine structure of exotic isotopes.
The technique of decay-assisted laser spectroscopy is presented, whereby the
isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay
tagging of the hyperfine components. Here, we present the first
hyperfine-structure measurements of the neutron-deficient francium isotopes
Fr, in addition to the identification of the low-lying states of
Fr performed at the CRIS experiment.Comment: Accepted for publication with Physical Review
Laser spectroscopy of francium isotopes at the borders of the region of reflection asymmetry
The magnetic dipole moments and changes in mean-square charge radii of the
neutron-rich isotopes were measured with the
newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at
ISOLDE, CERN, probing the to atomic
transition. The values for
and follow the observed increasing
slope of the charge radii beyond . The charge radii odd-even
staggering in this neutron-rich region is discussed, showing that
has a weakly inverted odd-even staggering while
has normal staggering. This suggests that both isotopes
reside at the borders of a region of inverted staggering, which has been
associated with reflection-asymmetric shapes. The value supports a shell model configuration for the
ground state. The values support the tentative
spin, and point to a intruder ground state configuration.Comment: Accepted for publication with Physical Review
Magnetic moments of Mg in time-odd relativistic mean field approach
The configuration-fixed deformation constrained relativistic mean field
approach with time-odd component has been applied to investigate the
ground-state properties of Mg with effective interaction PK1. The ground
state of Mg has been found to be prolate deformed, , with
the odd neutron in orbital and the energy -251.85 MeV which is close
to the data -252.06 MeV. The magnetic moment is
obtained with the effective electromagnetic current which well reproduces the
data self-consistently without introducing any
parameter. The energy splittings of time reversal conjugate states, the neutron
current, the energy contribution from the nuclear magnetic potential, and the
effect of core polarization are discussed in detail.Comment: 13 pages, 4 figure
- âŠ