A5017196126- Superconducting and THz Device Technology
- Atomic and Molecular Physics
- Astrophysical Phenomena and Observations
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic confinement fusion research
- Physics of Superconductivity and Magnetism
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Astronomical Observations and Instrumentation
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Particle accelerators and beam dynamics
- Mass Spectrometry Techniques and Applications
- Plasma Diagnostics and Applications
- Pulsars and Gravitational Waves Research
- Advanced Chemical Physics Studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- thermodynamics and calorimetric analyses
- Laser-Plasma Interactions and Diagnostics
- Geomagnetism and Paleomagnetism Studies
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- Advanced Thermoelectric Materials and Devices
Google (United States)
2025
The Ohio State University
2024
Museum Conservation Institute
2014
Smithsonian Institution
2014
Center for Astrophysics Harvard & Smithsonian
2001-2011
Harvard University
2003-2010
Smithsonian Astrophysical Observatory
2002-2005
Space Research Institute
2005
University of California, Santa Cruz
2005
Max Planck Institute for Extraterrestrial Physics
2005
view Abstract Citations (224) References (7) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A precision measurement of the X-ray polarization Crab Nebula without pulsar contamination. Weisskopf, M. C. ; Silver, E. H. Kestenbaum, L. Long, K. S. Novick, R. The linear has been precisely measured at 2.6 keV and 5.2 with OSO 8 graphite crystal polarimeters. 1.4 ms time resolution these instruments permitted removal any contribution to from pulsar. nebular is...
Wavelength measurements of n=3 to n=2 transitions in neonlike ${\mathrm{Xe}}^{44+}$, ${\mathrm{La}}^{47+}$, ${\mathrm{Nd}}^{50+}$, and ${\mathrm{Eu}}^{53+}$ have been made using a high-resolution Bragg-crystal spectrometer on the Princeton Large Torus tokamak. The cover wavelength regions 2.00--3.00 A\r{} include electric dipole magnetic quadrupole transitions. measured wavelengths are compared energy levels obtained from multiconfigurational Dirac-Fock calculation. Systematic differences...
In thermal-barrier experiments in the tandem mirror experiment upgrade, axial confinement times of 50 to 100 ms have been achieved. During enhanced we measured potential profile using a neutral-particle-beam probe. The experimental data agree qualitatively and quantitatively with theory formation mirror.Received 9 April 1984DOI:https://doi.org/10.1103/PhysRevLett.53.783©1984 American Physical Society
High-resolution spectra of Fe xxv have been observed from Princeton Large Torus tokamak discharges and are used for a detailed comparison with theoretical predictions Bely-Dubau, Gabriel, Volont\'e the ($1{s}^{2}nl\ensuremath{-}1s2pnl$, $n>~3$) dielectronic satellites at 1.85 \AA{}. The theory predicts significant apparent broadening resonance lines high-$Z$ heliumlike ions in high-temperature plasmas due to capture electrons into outer atomic shells. experimental results good general agreement.
New laboratory measurements using an electron beam ion trap and X-ray microcalorimeter are presented for the n = 3 to 2 Fe xvii emission lines in 15–17 Å range, along with new theoretical predictions a variety of energy distributions. This work improves upon our earlier on these by providing at more electron-impact energies (seven values from 846 1185 eV), performing situ determination window transmission, taking steps minimize impurity concentrations, correcting space charge shifts,...
We report new observations of emission line intensity ratios Fe XVII under controlled experimental conditions, using the National Institute Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. compare our collisional-radiative models atomic data computed in distorted wave R-matrix approximations, which follow transfer polarization level populations through radiative cascades. Our results for ratio 2p6 1S0-2p53d1P1 15.014 Å to 1S0-2p53d3D1 15.265 are 2.94 ±...
We present the Dark Energy Spectroscopic Instrument (DESI) Strong Lens Foundry. discovered $\sim 3500$ new strong gravitational lens candidates in DESI Legacy Imaging Surveys using residual neural networks (ResNet). observed a subset (51) of our Hubble Space Telescope (HST). All them were confirmed to be lenses. also briefly describe spectroscopic follow-up observations by and Keck NIRES programs. From this very rich dataset, number studies will carried out, including evaluating quality...
Temporally and spatially resolved profiles of the PDX soft x-ray spectra have been measured during single tokamak pulses circular divertor plasmas with a recently developed pulse-height analyzer. This detection system incorporates an array five vertically displaced sets lithium-drifted silicon detectors, each consisting three independent channels optimized for rapid data collection in adjacent energy regions. Simultaneous measurements emission integrated along chords plasma cross section...
The intercombination lines of the zinc sequence corresponding to transition 4s4p ${}^{3}$${P}_{1}$\ensuremath{\rightarrow}4${s}^{2}$ ${}^{1}$${S}_{0}$ have been observed for xenon, lanthanum, neodymium, europium, gadolinium, and ytterbium in Princeton Large Torus tokamak discharges.
Cosmic plasma conditions created in an electron beam ion trap (EBIT) make it possible to simulate the dependencies of key diagnostic X-ray lines on density, temperature, and excitation that exist astrophysical sources. We used a microcalorimeter for such laboratory astrophysics studies because has resolving power ≈1000, quantum efficiency approaching 100%, bandwidth spans energies from 0.2 keV 10 keV. Our microcalorimeter, coupled with optic increase effective solid angle, provides...
Certain applications of laser blow-off impurity injection, such as ion temperature measurement and spectral line identification, may require the ratio injected ions-to-plasma electron density to exceed 0.001. To achieve these concentrations we have relied on injection micron-sized clusters well monatomic species. In cases can no longer be regarded a nonperturbing trace sourced at plasma edge. We therefore studied variation parameters in PLT PDX function amount impurities, species mix, type...
view Abstract Citations (23) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Search for X-ray polarization in the Crab pulsar. Silver, E. H. ; Weisskopf, M. C. Kestenbaum, L. Long, K. S. Novick, R. Wolff, Results of a search pulsar are presented which were obtained by observing at 2.6 and 5.2 keV with identical polarimeters aboard OSO 8. The different portions light curve is analyzed, contribution due to nebula removed, results analysis given...
We report a fully relativistic close-coupling calculation of the electron impact excitation Ni xix to derive 3C/3D line intensity ratio, with an uncertainty 5%. Convergence respect both channel coupling effects and many interacting Rydberg series resonances has been achieved. New measurements in beam ion trap agree our calculation. show that x-ray ratio depends sensitively on energy beamwidth optically thin plasma. Accounting for this dependence improves accuracy abundance determination...
In this paper we report on the observation of characteristic "steps" in continuum spectrum high-temperature tokamak plasmas associated with recombination radiation from impurity ions. During special argon-seeded discharges Princeton Large Torus x-ray exhibited large enhancements over bremsstrahlung beginning energies 4.1 keV. This corresponds to radiative capture free electrons by hydrogenlike argon into ground state heliumlike argon. The size these edges increased unexpectedly values minor...
view Abstract Citations (19) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The first search for X-ray polarization in the Centaurus X-3 and Hercules X-1 pulsars. Silver, E. H. ; Weisskopf, M. C. Kestenbaum, L. Long, K. S. Novick, R. Wolff, Cen Her pulsars was performed by OSO 8 polarimeters 1975 July August, respectively. Three-sigma upper limits to of 13.5% 19% at 2.6 keV 5.2 keV, respectively, were obtained when data averaged over pulse...
view Abstract Citations (17) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The graphite crystal X-ray spectrometer on OSO-8. Kestenbaum, H. L. ; Cohen, G. Long, K. S. Novick, R. Silver, E. Weisskopf, M. C. Wolff, large-area aboard the OSO-8 satellite is described. instrument can be used to measure continuum profiles over energy band from 2 8 keV with a resolution of several tens electron volts and detect narrow line emission strong sources...
view Abstract Citations (12) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An upper limit to the linear X-ray polarization of Scorpius X-1. Weisskopf, M. C. ; Kestenbaum, H. L. Long, K. S. Novick, R. Silver, E. A measurement Sco X-1 with graphite-crystal polarimeters on OSO 8 satellite yields limits (3 sigmas) 2.7% and 4.9% at 2.6 keV 5.2 keV, respectively. The results are discussed in terms an accretion-disk model. Publication:...
A CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> TEA Laser (output ∼ 1 MW) has been used to pump methyl fluoride gas produce 10 W of far-infrared peak power at 496 μm. Since the oscillating bandwidth laser is broader than absorbing transition in fluoride, only part available effective pumping.