127 research outputs found
Storage-Ring Measurements of Hyperfine Induced Transition Rates in Berylliumlike Ions
The status of experimental measurements and theoretical calculations of the
hyperfine induced 2s2p 3P0 -> 2s2 1S0 transition rate in Be-like ions is
reviewed. Possible reasons, such as external electromagnetic fields and
competing E1M1 two-photon transitions, for presently existing significant
discrepancies between experiment and theory are discussed. Finally, directions
for future research are outlined.Comment: 10 pages, 4 figures, 30 references, submitted to the proceedings of
the 8th International Conference on Atomic and Molecular Data and Their
Applications (ICAMDATA), Gaithersburg, USA, September 30 - October 4, 201
Photoionization of astrophysically relevant atomic ions at PIPE
We review recent work on the photoionization of atomic ions of astrophysical
interest that has been carried out at the photon-ion merged-beams setup PIPE, a
permanently installed end station at the XUV beamline P04 of the PETRAIII
synchrotron radiation source operated by DESY in Hamburg, Germany. Our results
on single and multiple L-shell photoionization of Fe+, Fe2+, and Fe3+ ions and
on single and multiple K-shell photoionization of C-, C+, C4+, Ne+, and Si2+
ions are discussed in astrophysical contexts. Moreover, these experimental
results bear witness of the fact, that the implementation of the photon-ion
merged-beams method at one of the world's brightest synchrotron light sources
has led to a breakthrough for the experimental study of atomic inner-shell
photoionization processes with ions.Comment: 18 pages, 7 figures, 1 table, 113 reference
Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings
Dielectronic recombination (DR) of few-electron ions has evolved into a
sensitive spectroscopic tool for highly charged ions. This is due to
technological advances in electron-beam preparation and ion-beam cooling
techniques at heavy-ion storage rings. Recent experiments prove unambiguously
that DR collision spectroscopy has become sensitive to 2nd order QED and to
nuclear effects. This review discusses the most recent developments in
high-resolution spectroscopy of low-energy DR resonances, experimental studies
of KLL DR of very heavy hydrogenlike ions, isotope shift measurements of DR
resonances, and the experimental determination of hyperfine induced decay rates
in divalent ions utilizing DR.Comment: 6 pages, 5 figures, proceedings of the 4th Conference on Elementary
Processes in Atomic Systems, Cluj-Napoca, Romania, June 18-20, 2008, accepted
for publication in Nucl. Instrum. Methods
The effect of an external magnetic field on the determination of E1M1 two-photon decay rates in Be-like ions
In this work we report on ab initio theoretical results for the magnetic
field induced 2s2p ^3P_0 - 2s^2 ^1S_0 E1 transition for ions in the beryllium
isoelectronic sequence between Z=5 and 92. It has been proposed that the rate
of the E1M1 two-photon transition 2s2p ^3P_0 - 2s^2 ^1S_0 can be extracted from
the lifetime of the ^3P_0 state in Be-like ions with zero nuclear spin by
employing resonant recombination in a storage-ring. This experimental approach
involves a perturbing external magnetic field. The effect of this field needs
to be evaluated in order to properly extract the two-photon rate from the
measured decay curves. The magnetic field induced transition rates are
carefully evaluated and it is shown that, with a typical storage-ring field
strength, it is dominant or of the same order as the E1M1 rate for low- and
mid-Z ions. Results for several field strengths and ions are presented and we
also give a simple Z-dependent formula for the rate. We estimate the
uncertainties of our model to be within 5% for low- and mid-Z ions, and
slightly larger for more highly charged ions. Furthermore we evaluate the
importance of including both perturber states, ^3P_1 and ^1P_1, and it is shown
that excluding the influence of the ^1P_1 perturber overestimates the rate by
up to 26% for the mid-Z ions.Comment: 21 pages, 5 figure
Анализ данных о смертности в России для разработки корпоративной системы пропаганды здорового образа жизни населения
Выпускная квалификационная работа 117 с., 13 рис., 34 табл., 16 источников, 1 прил. Объектом исследования являются данные, предоставленные МО 슫Здоровье슻, стандартизованных вопросников на умерших лиц. Цель работы установить закономерности в уже существующих статистических данных и данных проведенных в данном исследовании для дальнейшего использования в корпоративной системе пропаганды здорового образа жизни. В процессе исследования проводился ряд исследований по влиянию курения на смертность, распространенности курения среди населения, влияние различных факторов на смертность от болезней систем-кровообращения, обзор методов статистического анализа для медицинских исследований и практика их применеия.Final qualifying work 117 p., 13 fig., 34 tab., 16 Sources, Appendix 1. The object of research is the data provided by the Medical Association "Health", standardized questionnaires on deceased persons. The goal of the work to establish patterns in the existing statistics and data conducted in this study for further use in the corporate system of promoting a healthy lifestyle. The study was conducted a number of studies on the effect of smoking on mortality, the prevalence of smoking among the population, the impact of various factors on mortality from diseases of the circulatory systems, a review of methods of statistical analysis for medical research and practice them of use
Interference effects in the photorecombination of argonlike Sc3+ ions: Storage-ring experiment and theory
Absolute total electron-ion recombination rate coefficients of argonlike
Sc3+(3s2 3p6) ions have been measured for relative energies between electrons
and ions ranging from 0 to 45 eV. This energy range comprises all dielectronic
recombination resonances attached to 3p -> 3d and 3p -> 4s excitations. A broad
resonance with an experimental width of 0.89 +- 0.07 eV due to the 3p5 3d2 2F
intermediate state is found at 12.31 +- 0.03 eV with a small experimental
evidence for an asymmetric line shape. From R-Matrix and perturbative
calculations we infer that the asymmetric line shape may not only be due to
quantum mechanical interference between direct and resonant recombination
channels as predicted by Gorczyca et al. [Phys. Rev. A 56, 4742 (1997)], but
may partly also be due to the interaction with an adjacent overlapping DR
resonance of the same symmetry. The overall agreement between theory and
experiment is poor. Differences between our experimental and our theoretical
resonance positions are as large as 1.4 eV. This illustrates the difficulty to
accurately describe the structure of an atomic system with an open 3d-shell
with state-of-the-art theoretical methods. Furthermore, we find that a
relativistic theoretical treatment of the system under study is mandatory since
the existence of experimentally observed strong 3p5 3d2 2D and 3p5 3d 4s 2D
resonances can only be explained when calculations beyond LS-coupling are
carried out.Comment: 11 pages, 7 figures, 3 tables, Phys. Rev. A (in print), see also:
http://www.strz.uni-giessen.de/~k
An Efficient, Movable Single-Particle Detector for Use in Cryogenic Ultra-High Vacuum Environments
A compact, highly efficient single-particle counting detector for ions of
keV/u kinetic energy, movable by a long-stroke mechanical translation stage,
has been developed at the Max-Planck-Institut f\"ur Kernphysik (Max Planck
Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics,
can operate at ambient temperatures down to 10 K and consist fully of
ultra-high vacuum (UHV) compatible, high-temperature bakeable and non-magnetic
materials. The set-up is designed to meet the technical demands of MPIK's
Cryogenic Storage Ring (CSR). We present a series of functional tests that
demonstrate full suitability for this application and characterise the set-up
with regard to its particle detection efficiency.Comment: 12 pages, 9 figures, version accepted for publication in Review of
Scientific Instrument
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