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Search Publications by: John D. Gillaspy (Fed)

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Displaying 1 - 25 of 314

New x-ray measurements shed light on discrepancy between experiment and QED

December 15, 2014
Author(s)
Lawrence T. Hudson, C T. Chantler, A.T. Payne, M N. Kinnane, John D. Gillaspy, L F. Smale, Albert Henins, J A. Kimpton, E Takacs
Quantum Electro-Dynamics (QED) is the best tested theory of our physical world, yet significant disagreements have emerged between attempts to apply QED to exotic atomic systems. A recent 15 parts-per-million (ppm) experiment on muonic hydrogen, in which

EUV spectra of Rb-like to Ni-like dysprosium ions in an electron beam ion trap

August 12, 2014
Author(s)
Deirdre Kilbane, G. O'Sullivan, Yuri A. Podpaly, John D. Gillaspy, Joseph Reader, Yuri Ralchenko
Extreme ultraviolet radiation emitted from highly-charged dysprosium ions was measured at the National Institute of Standards and Technology. The ions were created, trapped, and excited in an electron beam ion trap (EBIT), and the spectra were recorded

Extreme ultraviolet spectra and analysis of ?n=0 transitions in highly charged barium

July 4, 2014
Author(s)
Joseph Reader, John D. Gillaspy, Dmitry D. Osin, Yuri Ralchenko
Extreme ultraviolet spectra of highly charged barium atoms were produced with an electron beam ion trap (EBIT) and recorded with a flat-field grazing-incidence spectrometer. The spectra were measured in the wavelength range 4 nm to 24 nm with the beam

EUV spectra from N-shell ions of Gd, Dy and W

September 23, 2013
Author(s)
Deirdre Kilbane, John D. Gillaspy, Yuri Ralchenko, Joseph Reader, G. O'Sullivan
Measurements of extreme ultraviolet radiation from gadolinium, dysprosium and tungsten ions with an open n=4 shell were performed at the National Institute of Standards and Technology. The ions were produced and confined in an electron beam ion trap and

Magnetic-dipole lines in 3dn ions of high-Z elements: identification, diagnostic potential, and dielectronic resonances

September 23, 2013
Author(s)
Yuri Ralchenko, John D. Gillaspy, Joseph Reader, Dmitry D. Osin, John J. Curry, Yuri A. Podpaly
We present a review of measurements and analyses of extreme-ultraviolet magneticdipole (M1) lines in 50-60-times ionized atoms of tungsten, hafnium, tantalum, and gold with an open 3d shell. The spectra were measured with the electron beam ion trap at the

Anisotropic LMN dielectronic resonances from ratios of magnetic-dipole lines

July 13, 2013
Author(s)
Yuri Ralchenko, John D. Gillaspy
Signatures of multi-keV LMN dielectronic resonances in highly-charged 3dn ions of tungsten were detected in the intensity ratios of extreme-ultraviolet magnetic-dipole lines within ground configurations. The measurements were performed with an electron

Transition Energies of the D-lines in Na-like Ions

June 5, 2013
Author(s)
John D. Gillaspy, Dmitry D. Osin, Yuri Ralchenko, Joseph Reader, S A. Blundell
The NIST electron beam ion trap (EBIT) was used to measure the D1 (3s-3p1/2) and D2 (3s-3p3/2) transitions in Na-like ions of xenon, barium, samarium, gadolinium, dysprosium, erbium, tungsten, platinum, and bismuth. New relativistic many-body perturbation

Reply to Comment on "Testing Three-body Quantum Electrodynamics with Trapped Ti20+ Ions: Evidence for a Z-Dependent Divergence between Experiment and Calculation"

April 12, 2013
Author(s)
Lawrence T. Hudson, C T. Chantler, M N. Kinnane, John D. Gillaspy, A.T. Payne, L F. Smale, Albert Henins, Joshua M. Pomeroy, J A. Kimpton, E Takacs, K Makonyi
We find that Epp’s [1] hypothesis - namely that the current experimental data set is well represented by a small constant or zero offset from the predictions of Artemyev et al. [2] - is not supported by standard statistical analysis. We find that adding

Light polarization and quantum interference effects in unresolvable atomic lines: application to a precise measurement of the 6,7Li D2 lines.

March 7, 2013
Author(s)
Roger C. Brown, Saijun Wu, James V. Porto, Craig J. Sansonetti, Clayton Simien, Samuel M. Brewer, Joseph N. Tan, John D. Gillaspy
We characterize the effect of quantum interference of light scattering on the line shapes and measured line positions in atomic spectra. These effects occur when the excited state splittings are of order the excited state line widths, and represent an