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Application Acceleration on Current and Future Cray Platforms (open access)

Application Acceleration on Current and Future Cray Platforms

None
Date: May 11, 2010
Creator: Koniges, A.; Preissl, R.; Kim, J.; Eder, D.; Fisher, A.; Masters, N. et al.
System: The UNT Digital Library
Backscatter measurements for NIF ignition targets (open access)

Backscatter measurements for NIF ignition targets

None
Date: May 11, 2010
Creator: Moody, J. D.; Michel, P. A.; Bond, E.; Datte, P.; Krauter, K.; Glenzer, S. H. et al.
System: The UNT Digital Library
Characterizing high energy spectra of NIF ignition hohlraums using a differentially filtered high energy multi-pinhole X-ray imager (open access)

Characterizing high energy spectra of NIF ignition hohlraums using a differentially filtered high energy multi-pinhole X-ray imager

Understanding hot electron distributions generated inside hohlraums is important to the ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with the target materials. We used an array of 18 pinholes, with four independent filter combinations, to image entire hohlraums with a magnification of 0.87x during the hohlraum energetics campaign on NIF. Comparing our results with hohlraum simulations indicates that the characteristic 30 keV hot electrons are mainly generated from backscattered laser plasma interactions rather than from hohlraum hydrodynamics.
Date: May 11, 2010
Creator: Park, H.; Dewald, E. D.; Glenzer, S.; Kalantar, D. H.; Kilkenny, J. D.; MacGowan, B. J. et al.
System: The UNT Digital Library
DRAINING HAZARDOUS FLUIDS DURING BUILDING 221-1F DEACTIVATION AT THE SAVANNAH RIVER SITE (open access)

DRAINING HAZARDOUS FLUIDS DURING BUILDING 221-1F DEACTIVATION AT THE SAVANNAH RIVER SITE

Several years ago, SRS completed a four year mission to decommission {approx}250 excess facilities. As part of that effort, SRS deactivated multiple facilities (e.g. Building 247-F, Naval Fuels Facility, and Building 211-F, Outside Facilities for F-Canyon) that contained extensive piping systems filled with hazardous material (e.g. nitric acid). Draining of hazardous materials from piping was successfully completed in all facilities without incident. In early 2009, the decommissioning program at SRS was restarted as a result of funding made available by the American Recovery & Reinvestment Act (ARRA). Under ARRA, draining of piping containing hazardous material was initiated in multiple facilities including Building 221-1F (or A-Line). This paper describes and reviews the draining of piping containing hazardous materials at A-Line, with emphasis on an incident involving the draining of nitric acid. The paper is intended to be a resource for engineers, planners, and project managers, who face similar draining challenges.
Date: May 11, 2010
Creator: Musall, J.
System: The UNT Digital Library
The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector (open access)

The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector

The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.
Date: May 11, 2010
Creator: Collaboration, IceCube & Abbasi, R.
System: The UNT Digital Library
An imaging proton spectrometer for short-pulse laser plasma experiments (open access)

An imaging proton spectrometer for short-pulse laser plasma experiments

Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better characterize these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only measure proton energy distribution with high resolution, but also provide its angular characteristics. The information obtained from this spectrometer compliments those from commonly used diagnostics including radiochromic film packs, CR39 nuclear track detectors, and non-imaging magnetic spectrometers. The basic characterizations and sample data from this instrument are presented.
Date: May 11, 2010
Creator: Chen, H.; Hazi, A.; van Maren, R.; Chen, S.; Fuchs, J.; Gauthier, M. et al.
System: The UNT Digital Library
Nanoheterostructure Cation Exchange: Anionic Framework Conservation (open access)

Nanoheterostructure Cation Exchange: Anionic Framework Conservation

In ionic nanocrystals the cationic sub-lattice can be replaced with a different metal ion via a fast, simple, and reversible place-exchange, allowing post-synthetic modification of the composition of the nanocrystal, while preserving its size and shape. Here, we demonstrate for the first time that during such an exchange, the anionic framework of the crystal is preserved. When applied to nanoheterostructures, this phenomenon ensures that compositional interfaces within the heterostructure are conserved throughout the transformation. For instance, a morphology composed of a CdSe nanocrystal embedded in a CdS rod (CdSe/CdS) was exchanged to a PbSe/PbS nanorod via a Cu2Se/Cu2S structure. During every exchange cycle, the seed size and position within the nanorod were preserved, as evident by excitonic features, Z-contrast imaging, and elemental line-scans. Anionic framework conservation extends the domain of cation exchange to the design of more complex and unique nanostructures.
Date: May 11, 2010
Creator: Jain, Prashant K.; Amirav, Lilac; Aloni, Shaul & Alivisatos, A. Paul
System: The UNT Digital Library