340 research outputs found
Precision measurements in nuclear {\beta}-decay with LPCTrap
The experimental achievements and the current program with the LPCTrap device
installed at the LIRAT beam line of the SPIRAL1-GANIL facility are presented.
The device is dedicated to the study of the weak interaction at low energy by
means of precise measurements of the {\beta}-{\nu} angular correlation
parameter. Technical aspects as well as the main results are reviewed. The
future program with new available beams is briefly discussed.Comment: Annalen der Physik (2013
Action at a distance as a full-value solution of Maxwell equations: basis and application of separated potential's method
The inadequacy of Li\'{e}nard-Wiechert potentials is demonstrated as one of
the examples related to the inconsistency of the conventional classical
electrodynamics. The insufficiency of the Faraday-Maxwell concept to describe
the whole electromagnetic phenomena and the incompleteness of a set of
solutions of Maxwell equations are discussed and mathematically proved. Reasons
of the introduction of the so-called ``electrodynamics dualism concept"
(simultaneous coexistence of instantaneous Newton long-range and
Faraday-Maxwell short-range interactions) have been displayed. It is strictly
shown that the new concept presents itself as the direct consequence of the
complete set of Maxwell equations and makes it possible to consider classical
electrodynamics as a self-consistent and complete theory, devoid of inward
contradictions. In the framework of the new approach, all main concepts of
classical electrodynamics are reconsidered. In particular, a limited class of
motion is revealed when accelerated charges do not radiate electromagnetic
field.Comment: ReVTeX file, 24pp. Small corrections which do not have influence
results of the paper. Journal reference is adde
Transport and cooling of singly-charged noble gas ion beams
The transport and cooling of noble gas singly-charged ion beams by means of a
Radio Frequency Quadrupole Cooler Buncher (RFQCB) have been studied at the
LIMBE low energy beam line of the GANIL facility. Ions as light as
have been cooled and stored before their extraction in bunches using as
buffer gas. Bunches characteristics have been studied as a function of the
parameters of the device. Sizeable transmissions of up to 10 have been
obtained. A detailed study of the lifetime of ions inside the buncher has been
performed giving an estimate of the charge exchange cross-section. Results of a
microscopic Monte-Carlo transport code show reasonable agreement with
experimental data.Comment: 13 figure
The WITCH experiment: Acquiring the first recoil ion spectrum
The standard model of the electroweak interaction describes beta-decay in the
well-known V-A form. Nevertheless, the most general Hamiltonian of a beta-decay
includes also other possible interaction types, e.g. scalar (S) and tensor (T)
contributions, which are not fully ruled out yet experimentally. The WITCH
experiment aims to study a possible admixture of these exotic interaction types
in nuclear beta-decay by a precise measurement of the shape of the recoil ion
energy spectrum. The experimental set-up couples a double Penning trap system
and a retardation spectrometer. The set-up is installed in ISOLDE/CERN and was
recently shown to be fully operational. The current status of the experiment is
presented together with the data acquired during the 2006 campaign, showing the
first recoil ion energy spectrum obtained. The data taking procedure and
corresponding data acquisition system are described in more detail. Several
further technical improvements are briefly reviewed.Comment: 11 pages, 6 figures, conference proceedings EMIS 2007
(http://emis2007.ganil.fr), published also in NIM B:
doi:10.1016/j.nimb.2008.05.15
Growth modes of Fe(110) revisited: a contribution of self-assembly to magnetic materials
We have revisited the epitaxial growth modes of Fe on W(110) and Mo(110), and
propose an overview or our contribution to the field. We show that the
Stranski-Krastanov growth mode, recognized for a long time in these systems, is
in fact characterized by a bimodal distribution of islands for growth
temperature in the range 250-700°C. We observe firstly compact islands
whose shape is determined by Wulff-Kaischev's theorem, secondly thin and flat
islands that display a preferred height, ie independant from nominal thickness
and deposition procedure (1.4nm for Mo, and 5.5nm for W on the average). We
used this effect to fabricate self-organized arrays of nanometers-thick stripes
by step decoration. Self-assembled nano-ties are also obtained for nucleation
of the flat islands on Mo at fairly high temperature, ie 800°C. Finally,
using interfacial layers and solid solutions we separate two effects on the
preferred height, first that of the interfacial energy, second that of the
continuously-varying lattice parameter of the growth surface.Comment: 49 pages. Invited topical review for J. Phys.: Condens. Matte
Transfer of Communication Skills to the Workplace during Clinical Rounds : Impact of a Program for Residents
peer reviewe
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