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Physics

Radiation

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Displaying 101 - 125 of 264

HIGH EFFICIENCY CARBON NANOTUBE THREAD ANTENNAS

November 3, 2017
Author(s)
Christopher L. Holloway, Aydin Babajgabni, Chris Long, David R. Novotny, Nate Orloff, E. A. Bengio, Damir Senic, Lauren W. Taylor, Dimitri E. Tsentalovich
Although previous research has explored the underlying theory of high-frequency behavior of carbon nanotubes (CNTs) and CNT bundles for antennas, there is a gap in the literature for direct experimental measurements of radiation efficiency. These

Supplement 2 to the 2004 update of the AAPM Task Group No. 43 1 Report: Joint recommendations by the AAPM and GEC-ESTRO

September 30, 2017
Author(s)
Michael G. Mitch, Mark J. Rivard, Facundo Ballester, Wayne M. Butler, Larry A. DeWerd, Geoffrey S. Ibbott, Christopher Melhus
Since publication of the 2004 update to the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (TG-43U1) and its 2007 supplement (TG-43U1S1), several new low- energy photon-emitting brachytherapy sources have become available

Large Area Alpha Sources with a Lip: Integral Counting and Spectral Distortions

August 31, 2017
Author(s)
Lynne E. King, Ryan P. Fitzgerald, Ronald Tosh
The detection efficiency for large area alpha sources with adjustable heights of a raised lip around the edge were measured by 2π gas-filled proportional counter. The variations in low- energy spectral shape were modeled using a Geant4 radiation and charge

High-precision measurement of the X-ray Cu K-alpha spectrum

May 12, 2017
Author(s)
Marcus H. Mendenhall, Albert Henins, Lawrence T. Hudson, Csilla I. Szabo-Foster, Donald A. Windover, James P. Cline
The structure of the x-ray emission lines of the Cu Kα complex has been remeasured on a newly commissioned instrument, in a manner directly traceable to the Système Internationale definition of the meter. In this measurement, the region from 8000 to 8100

Graphene microcapsule arrays for combinatorial electron microscopy and spectroscopy in liquids

April 27, 2017
Author(s)
Alexander Yulaev, Hongxuan Guo, Evgheni Strelcov, Lei Chen, Ivan Vlasssiouk, Andrei Kolmakov
An atomic-scale thickness, molecular impermeability, low atomic number, and mechanical strength make graphene an ideal electron transparent membrane for scanning electron microscopy and spectroscopy in liquids. Here, we present a novel sample platform made

Enabling photoemission electron microscopy in liquids via graphene-capped microchannel arrays

February 8, 2017
Author(s)
Hongxuan Guo, Evgheni Strelcov, Alexander Yulaev, Jian Wang, Narayana Appathurai, Stephen Urquhart, John Vinson, Subin Sahu, Michael P. Zwolak, Andrei Kolmakov
Photoelectron emission microscopy (PEEM) is a powerful tool to spectroscopically access dynamic surface processes at the nanoscale but is traditionally limited to ultra-high or moderate vacuum conditions. Here, we develop a novel graphene-capped

60 Year Anniversary of Applied Radiation and Isotopes

December 14, 2016
Author(s)
Bert M. Coursey
Those readers who have a library with the first bound copies of ARI may find it enjoyable to compare Volume 1, No.1 from 1956 with an issue from Volume 118 in 2016. The range of applications has shifted away from agricultural and industrial uses of

NIST Electron Elastic-Scattering Cross-Section Database, Version 4.0

September 14, 2016
Author(s)
Cedric J. Powell, Aleksander Jablonski, Francesc Salvat, Angela Y. Lee
Version 4.0 of this database (SRD 64) provides values of differential elastic-scattering cross sections, total elastic-scattering cross sections, phase shifts, and transport cross sections for elements with atomic numbers from 1 to 96 and for electron

Morphology-insensitive Performance Facilitates Transition from Spin-Coating to Roll-to-Roll Coating For High-Performance, Solution-Processed Solar Cells

August 2, 2016
Author(s)
Lee J. Richter, Jonathan Downing, Sebastian Engmann, Hyun W. Ro, Andrew A. Herzing, Dean M. DeLongchamp, Subhrangsu Mukherjee, Harald Ade, Maged Addelsamie, Aram Amassian, Yuhang Liu, He Yan
Solution processing via roll-to-roll (R2R) coating promises a low cost, low thermal-budget, sustainable revolution for the production of solar cells. Yet virtually all high performance solution processed research cells have been demonstrated by spin

XAFS Data Interchange: A single spectrum XAFS data file format

June 9, 2016
Author(s)
Bruce D. Ravel, M. Newville
We propose a standard data format for the interchange of XAFS data. The XAFS Data Interchange (XDI) standard is meant to encapsulate a single spectrum of XAFS along with relevant metadata. XDI is a text-based format with a simple syntax which clearly

Energetic Electrons Driven in the Polarization Direction of an Intense Laser Beam Incident Normal to a Solid Target

June 1, 2016
Author(s)
Lawrence T. Hudson, John F. Seely, Nino R. Pereira, H. Chen, G.J. Williams, R.P. Drake, C.C. Kuranz, C.A. Di Stefano, J. Park
Experiments were performed at the LLNL Titan laser to measure the propagation direction of the energetic electrons that were generated during the interaction of the polarized laser beam with solid targets in the case of normal incidence. The energetic

The New SURF Beamline 3

May 18, 2016
Author(s)
Robert E. Vest
A new beamline is being commissioned at the Synchrotron Ultraviolet Radiation Facility (SURF III) on the Gaithersburg, MD campus of the National Institute of Standards and Technology (NIST). SURF III is a 380-MeV synchrotron radiation source providing

Use of the Bethe Equation for Inner-Shell Ionization by Electron Impact

May 13, 2016
Author(s)
Cedric J. Powell, Xavier Llovet, Francesc Salvat
We analyzed calculated cross sections for K-, L-, and M-shell ionization by electron impact to determine the energy ranges over which these cross sections are consistent with the Bethe equation for inner-shell ionization. Our analysis was performed with K

Neutron Limit on the Strongly-Coupled Chameleon Field

March 11, 2016
Author(s)
Michael G. Huber, Muhammad D. Arif, David G. Cory, R. Haun, B. Heacock, Joachim Nsofini, Dimitry A. Pushin, P Saggu, C.B Shahi, William M. Snow, A.R. Young
The physical origin of the dark energy which causes the accelerated expansion rate of the universe is one of the major open questions of cosmology. One set of theories postulates the existence of a self-interacting scalar eld for dark energy coupling to

Morphological origins of polarization-induced scattering anisotropy from organic thin films

January 14, 2016
Author(s)
Eliot Gann, Brian A. Collins, Maolong Tang, John R. Tumbleston, Subhrangsu Mukherjee, Harald W. Ade
Anisotropic scattering patterns have been observed from organic thin films that are isotropic on the scale of the probe in polarized resonant X-ray scattering experiments. The symmetry is broken by local correlations between molecular orientation and

Observation of Iron Spin-States using Tabletop X-ray Emission Spectroscopy and Microcalorimeter Sensors

December 2, 2015
Author(s)
Young Il Joe, Galen C. O'Neil, Luis Miaja Avila, Joseph W. Fowler, Kevin L. Silverman, Daniel S. Swetz, Joel N. Ullom, Ralph Jimenez
X-ray emission spectroscopy (XES) is a powerful probe of the electronic and chemical state of elemental species embedded within more complex compounds. X-ray sensors that combine high resolving power and high collecting efficiency are desirable for photon
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