Options
D'Arcy, Rebekah
Preferred name
D'Arcy, Rebekah
Official Name
D'Arcy, Rebekah
Research Output
Now showing 1 - 4 of 4
- PublicationTungsten spectra recorded at the LHD and comparison with calculations(IOP Science, 2010-10)
; ; ; ; ; ; ; ; ; ; ; We have measured extreme ultraviolet (EUV) spectra from highly charged tungsten ions in low-density and high-temperature plasmas produced in the Large Helical Device at the National Institute for Fusion Science. The EUV spectra emitted after injection of a tungsten pellet into a hydrogen plasma were recorded at plasma temperatures of 1.5 and 3 keV and were dominated by an intense transition array in the 4.5–6.5 nm region, the profile and extent of which was different in both spectra. Some discrete lines present were identified by comparison with existing spectral data while atomic structure calculations showed that the dominant emission in both arose from Δn = 0, n = 4–n = 4 transitions and the main differences could be attributed to the appearance of the 4p–4d and 4s–4p transitions from W XXXIX to W XLVI in the higher temperature spectrum. Comparison with calculations showed that the dominant emission in both temperature regimes arose from stages where the 4f subshell was either almost or completely stripped. We also investigated if the effect of low density favours transitions to the lowest level as observed in recently reported results.654Scopus© Citations 82 - PublicationConfiguration Interaction in Charge Exchange Spectra of Tin and Xenon(IOP Publishing, 2011)
; ; ; ; ; ; ; ; ; ; ; Charge state specific extreme ultraviolet spectra from both tin ions and xenon ions have been recorded at Tokyo Metropolitan University. The Electron Cyclotron Resonance Source spectra were produced from charge exchange collisions between the ions and rare gas target atoms. In order to identify unknown spectral lines of tin and xenon, atomic structure calculations were performed for Sn14+ - Sn17+ and for Xe 16+ - Xe20+ using the Hartree-Fock with Configuration Interaction code of Cowan. The energies of the capture states involved in the single electron process that occurs in these slow collisions are estimated using the classical over barrier model.686Scopus© Citations 2 - PublicationSpectral and temporal behavior of an alkali metal plasma extreme ultraviolet source for surface morphology applications(American Institute of Physics, 2011-02-28)
; ; ; ; ; ; ; ; We have characterized the emission spectrum and temporal history of a pure potassium plasma in a capillary discharge. Strong broadband emission was observed around 40 nm due to 3s−3p, 3p−3d, and 3d−4f transitions in ions ranging from K2+ to K4+ at a time-integrated electron temperature of about 12 eV. The temporal behavior of this emission strongly follows the recombination phase in the plasma and it was successfully reproduced by a hydrodynamic simulation of the potassium plasma which accounted for atomic processes.388Scopus© Citations 3 - PublicationMeasurement of EUV spectra from high Z elements in the Large Helical Device(American Institute of Physics, 2010-09-21)
; ; ; ; ; ; ; ; ; ; ; ; ; Extreme ultra-violet (EUV) emission spectra from highly charged tin, xenon and tungsten ions have been measured in optically thin high-temperature plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science by using a grazing incidence spectrometer and a tracer-encapsulated solid pellet (TESPEL) injector. Quasi-continuous spectral features arising from unresolved transition array (UTA) of open 4d subshell ions were commonly observed for tin, xenon and tungsten around 13.5, 11, and 5 nm, respectively, when edge plasma was cooled enough. The spectral appearance obviously depends on edge electron temperature and atomic number. In the case of intermediate edge temperature, sharp discrete lines from highly charged open 4s or 4p subshell ions are clearly observed for tin and xenon in longer wavelength side of the UTAs but not for tungsten. Assignments of the strong discrete lines have been performed with the help of comparisons with the other experimental data and the theoretical calculations by Cowan code. Contribution of open 4f subshell ions should also be considered to interpret the whole spectra from tungsten ions.325Scopus© Citations 2