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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Method of aligning a laser-based radiation source

A method for temporally and spatially aligning a laser-based x-ray source and maintaining alignment is disclosed. A pump laser beam, which interacts with a plasma source to create an electron beam, is aligned with the electron beam. A scattering laser beam is overlapped with the pump laser beam at an intersection point. The pump laser beam and scattering laser beam alignments are monitored and adjusted to maintain optimal alignment during operation of the laser-based x-ray source.

Umstadter, Donald↗
DOE OSTI2017

Developing High-Energy Laser-Driven Bremsstrahlung Radiation Sources for Imaging and Analysis of Nuclear Waste Packages - 17300

Radiographic imaging of small scale simulated nuclear waste packages (a 28 mm uranium penny encapsulated in grout) was achieved using a single pulse exposure from an x-ray source driven by a high-power laser. The high-energy laser pulse was generated at the Vulcan laser facility, which focused the photon burst onto a tantalum target foil in order to produce a bright burst of highly penetrating x-rays (with energy >500 keV) from a source size less than 0.5 mm. The sample was imaged using BAS-TR and BAS-SR image plates alongside a Thallium doped Caesium Iodide scintillator-based detector coupled to CCD chips for rapid image acquisition. The penny was resolved to sub-mm accuracy over a 30 cm{sup 2} scan area from a single shot. In addition, on a parallel beamline, neutron generation (of 10{sup 7}-10{sup 9} neutrons per steradian per pulse) was achieved, thereby demonstrating the potential application for criticality testing of waste packages. The principle concern regarding intermediate level waste (ILW) containers is the internal volumetric expansion due to the formation of corrosion products. Therefore, simulated waste samples with hydride corrosion have been formed and characterised in order to emulate this phenomenon. In addition, samples containing controlled isotopic ratios have been formed. This next generation of simulated waste samples have been produced in preparation for a second phase of analysis at the Vulcan laser facility to quantify the identification ability of radiographic imaging and characterisation accuracy of neutronics measurements. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material and this paper details the next phase of technological development. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1979

Directivity of acoustic radiation from sources

The radiation properties of acoustic monopoles and dipoles are described, as well as the directivity of radiation from these sources in a free field and in the presence of an absorptive surface. The kinematic effects on source radiation due to translation and rotation are discussed. Experimental measurements of sound from an acoustic monopole in motion and the characteristics of helicopter rotor and propeller noise are reviewed. Several essential concepts required by noise control engineers making measurements of noise from moving sources in the proximity of the ground are introduced.

Lansing, D. L.↗