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Search Publications by: Joseph N. Tan (Fed)

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Displaying 1 - 25 of 64

Determination of electron beam energy in measuring the electron-impact ionization cross section of He-like Fe24+

March 17, 2023
Author(s)
Yuri Ralchenko, Galen O'Neil, Paul Szypryt, Joseph N. Tan, Aung S. Naing, Yang Yang, Dipti Dipti, Amy Gall, Adam Hosier, David Schultz, Randall Smith, Nancy Brickhouse, Endre Takacs
In an effort to measure electron-impact ionization (EII) cross sections of He-like $Fe^24+}$ at the electron beam ion trap (EBIT) facility of the National Institute of Standards and Technology (NIST), we have experimentally determined the corrections to

Background and blended spectral line reduction in precision spectroscopy of EUV and x-ray transitions in highly charged ions

March 3, 2023
Author(s)
Yuri Ralchenko, Joseph N. Tan, Aung S. Naing, Galen O'Neil, Paul Szypryt, Dipti Dipti, Grant Mondeel, Roshani Silwal, Alain Lapierre, Steven Blundell, Gerald Gwinner, Antonio Camargo Villari, Endre Takacs
We report a method in EBIT spectral analysis that reduces signal from contaminant lines of 1 known or unknown origin. We utilize similar ion charge distributions of heavy highly charged ions 2 that create similar potentials for lighter contaminating

Analysis of E3 Transitions in Ag-like High-Z Ions Observed with the NIST EBIT

March 1, 2023
Author(s)
Yuri Ralchenko, David La Mantia, Aung S. Naing, Paul Szypryt, Joseph N. Tan, Endre Takacs, Dipti Dipti, Yang Yang, Adam Hosier, Hunter Staiger
We report measurements and identification of the E3 4f$_7/2,5/2}$-5s$_1⁄2$ transitions and E1 allowed transitions in Ag-like W (Z=74), Re (Z=75), and Ir (Z=77). The spectra were recorded at the NIST EBIT using a grazing-incidence EUV spectrometer. The

Identifications of extreme ultraviolet spectra of Br-like to Ni-like neodymium ions using an electronbeam ion trap

April 30, 2021
Author(s)
C. Suzuki, Dipti Goyal, Y. Yang, A. Gall, Roshani Silwal, S. Sanders, Aung S. Naing, Joseph N. Tan, Endre A. Takacs, Yuri Ralchenko
Charge-resolved extreme ultraviolet spectra of open N-shell neodymium (Nd) ions have been recorded in an electron beam ion trap facility at the National Institute of Standards and Technology. The measurements have been performed for nominal electron beam

Measurement of the 2P1/2-2P3/2 fine structure splitting in fluorine-like Kr, W, Re, Os and Ir

September 2, 2020
Author(s)
Galen O'Neil, Samuel C. Sanders, Paul Szypryt, Dipti Goyal, Amy Gall, Yang Yang, Samuel M. Brewer, W.Bertrand (Randy) Doriese, Joseph Fowler, Daniel Swetz, Joseph N. Tan, Joel Ullom, Andrey V. Volotka, Endre Takacs, Yuri Ralchenko
Quantum electrodynamics (QED) is currently considered to be one of the most accurate theories of fundamental interactions. As its extraordinary precision offers unique scientific opportunities, e.g., search for new physics, stringent experimental tests of

A transition-edge sensor-based x-ray spectrometer for the study of highly charged ions at the National Institute of Standards and Technology electron beam ion trap

December 16, 2019
Author(s)
Paul Szypryt, Galen C. O'Neil, Endre Takacs, Joseph N. Tan, Sean W. Buechele, Aung Naing, Douglas A. Bennett, William B. Doriese, Malcolm S. Durkin, Joseph W. Fowler, Johnathon D. Gard, Gene C. Hilton, Kelsey M. Morgan, Carl D. Reintsema, Daniel R. Schmidt, Daniel S. Swetz, Joel N. Ullom, Yuri Ralchenko
We report on the design, commissioning, and initial measurements of a Transition-Edge Sensor (TES) x-ray spectrometer for the Electron Beam Ion Trap (EBIT) at the National Institute of Standards and Technology (NIST). Over the past few decades, the NIST

On Low-Energy Tail Distortions in the Detector Response Function of X-Ray Microcalorimeter Spectrometers

November 21, 2019
Author(s)
Galen C. O'Neil, Paul Szypryt, Endre Takacs, Joseph N. Tan, Sean W. Buechele, Aung Naing, Young I. Joe, Daniel S. Swetz, Daniel R. Schmidt, William B. Doriese, Johnathon D. Gard, Carl D. Reintsema, Joel N. Ullom, John S. Villarrubia, Yuri Ralchenko
We use narrow spectral lines from the X-ray spectra of various highly charged ions to measure low-energy tail-like deviations from a Gaussian response function in a microcalorimeter X-ray spectrometer with Au absorbers at energies from 650 to 3320 eV. We

Capture of Highly Charged Ions in a Pseudo-Hyperbolic Paul Trap

July 12, 2019
Author(s)
Joan M. Dreiling, Aung S. Naing, Joseph N. Tan, Joshua Hanson, Shannon Hoogerheide, Samuel M. Brewer
The confinement of ions in a radio-frequency (RF) trap (also known as a Paul trap) has proven to be advantageous in many applications. Typically, singly- or few-times-ionized atoms can be created in situ within the ion trap. Highly charged ions, on the

Lifetime of the metastable 2 P 1/2 state of F-like Ar 9+ isolated in a compact Penning trap

September 6, 2018
Author(s)
Samuel M. Brewer, Joan M. Dreiling, Nicholas D. Guise, Shannon M. Hoogerheide, Aung Naing, Joseph N. Tan
Multiple-ionized atoms can be captured at low energy in a compact Penning trap, allowing the isolation of a single charge state to measure the radiative lifetime of an atomic state that decays via weakly allowed transitions. Such a measurement is reported

Experiments with highly-ionized atoms in unitary Penning traps

August 14, 2015
Author(s)
Shannon Hoogerheide, Aung Naing, Joan M. Dreiling, Samuel M. Brewer, Nicholas D. Guise, Joseph N. Tan
Highly-ionized atoms with special properties have been proposed for interesting applications, including potential candidates for a new generation of optical atomic-clocks at the 1 part in 1019 level of precision, quantum-information processing, and tests

A Miniature EBIT with Ion Extraction for Isolating Highly Charged Ions

May 28, 2015
Author(s)
Shannon Hoogerheide, Joseph N. Tan
We report on the development of a room-temperature miniature electron beam ion trap (EBIT) for efficient production of charge states with relatively low ionization energies. A unitary Penning trap is modified slightly to provide the magnetic field and

Tests of Theory in Rydberg States of One-electron Ions

July 1, 2014
Author(s)
Joseph N. Tan, Peter J. Mohr
Comparison of optical frequency measurements to predictions of quantum electrodynamics (QED) for Rydberg states of one-electron ions can test theory and allow new determinations of constants of nature to be made. Simplifications in the QED theory of high

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

Testing Three-body Quantum Electrodynamics with Trapped Ti-20 Ions: Evidence for a Z-Dependent Divergence between Experiment and Calculation

October 10, 2012
Author(s)
Lawrence T. Hudson, C T. Chantler, Mark N. Kinnane, John D. Gillaspy, A.T. Payne, L F. Smale, Albert Henins, Joseph N. Tan, J A. Kimpton, E Takacs, K Makonyi, Joshua M. Pomeroy
We report the measurement of the w (1s2p 1P1 ! 1s2 1S0) resonance line transition energy in helium-like titanium. Our result, 4749.85(7) eV, deviates from the most recent ab initio prediction by three times our experimental uncertainty and by many times

Towards One-electron Ions in Rydberg States for Laser Spectroscopy

July 30, 2012
Author(s)
Joseph N. Tan, Samuel M. Brewer, Nicholas D. Guise
Simple quantum systems play important roles in the determination of fundamental constants. Very recently at NIST, bare nuclei created in an EBIT were extracted and captured in a novel compact Penning trap. This is a step towards production of one-electron

Penning traps with unitary architecture for storage of highly charged ions

February 15, 2012
Author(s)
Joseph N. Tan, Samuel M. Brewer, Nicholas D. Guise
Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used to produce 0.32 T for ion trapping in unitary architectures that functionally couple the electric and

Absolute transition frequencies and quantum interference in a frequency comb based measurement of the 6,7Li D lines

July 6, 2011
Author(s)
Craig J. Sansonetti, Clayton Simien, John D. Gillaspy, Joseph N. Tan, Samuel M. Brewer, Roger C. Brown, Saijun Wu, James V. Porto
Optical frequencies of the D lines of 6,7Li were measured with a relative accuracy of 5x10-11 using an optical comb synthesizer. Quantum interference in the laser induced fluorescence for the partially-resolved D2 lines was found to produce polarization

Experiment at NIST towards one-electron ions in circular Rydberg states

June 20, 2011
Author(s)
Joseph N. Tan, Samuel M. Brewer, Nicholas D. Guise
An experimental effort is underway at NIST to enable tests of theory with oneelectron ions synthesized in circular Rydberg states from captured bare nuclei. Problematic effects which limit the accuracy of predicted energy levels for low-lying states are

Fe xvii X-ray Line Ratios for Accurate Astrophysical Plasma Diagnostics

February 20, 2011
Author(s)
John D. Gillaspy, E. H. Silver, L. Tedesco, Joseph N. Tan, Joshua M. Pomeroy, J M. Laming, G.-X. Chen, T. Lin
New laboratory measurements of the Ne-like Fe xvii x-ray lines in the 15-17 Angstrom range are presented, along with new theoretical predictions. These results establish consistency between independent laboratories and opens the door to trustworthy

EUV Spectral Lines of Highly-Charged Hf, Ta and Au Ions Observed with an Electron Beam Ion Trap

January 12, 2011
Author(s)
Ilija Draganic, Yuri Ralchenko, Joseph Reader, John D. Gillaspy, Joseph N. Tan, Joshua M. Pomeroy, Samuel M. Brewer, Dmitry D. Osin
Extreme ultraviolet spectra of highly charged hafnium, tantalum, and gold were produced with an electron beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST) and recorded with a flat-field grazing-incidence spectrometer in the

Progress at NIST in measuring the D-lines of Li isotopes using an optical frequency comb

December 20, 2010
Author(s)
Clayton Simien, Samuel M. Brewer, Joseph N. Tan, John D. Gillaspy, Craig J. Sansonetti
Precise spectroscopic experiments with light atoms can provide information about nuclear properties that are very difficult to obtain in electron scattering experiments. For example, relative nuclear radii of low-Z isotopes can be determined accurately