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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Challenges for In vitro to in Vivo Extrapolation of Nanomaterial Dosimetry for Human Risk Assessment

The proliferation in types and uses of nanomaterials in consumer products has led to rapid application of conventional in vitro approaches for hazard identification. Unfortunately, assumptions pertaining to experimental design and interpretation for studies with chemicals are not generally appropriate for nanomaterials. The fate of nanomaterials in cell culture media, cellular dose to nanomaterials, cellular dose to nanomaterial byproducts, and intracellular fate of nanomaterials at the target site of toxicity all must be considered in order to accurately extrapolate in vitro results to reliable predictions of human risk.

in vitro↗
DOE OSTI2015

Integrating and Live-time Radiation Dosimetry by Optical Crystal Damage, Initial Results with Neutrons

Radiation damage can be assessed through many techniques, though the assessment is usually offline and shows only integrated dose. Transparent crystals can be optically monitored for radiation damage nondestructively, to serve as a detector for both immediate dose and integrated dose for signatures of radiation exposure history. There is also some difference in gamma-ray and neutron interactions which can be observed. Gamma ray interactions primarily produce electron displacements, which are preserved as color centers in ionic crystals and produce specific spectral absorption lines. Neutron interactions strongly produce lattice displacements that affect the index of refraction. The differences may allow us to use inexpensive crystals for long time neutron monitoring. Spectroscopic absorption lines can be quantified using prior technology, but due to prior limits in phase sensitivity there was no previous use of index of refraction measurements. Using novel techniques based on intracavity phase interferometry to assess lattice displacements, we are able to examine neutron irradiation in CaF2 crystals. Initial results with neutrons will be presented.

99 GENERAL AND MISCELLANEOUS↗