Nerine Cherepy | Lawrence Livermore National Lab (original) (raw)
Papers by Nerine Cherepy
We are conducting research into the direct electrochemical conversion of reactive carbons into el... more We are conducting research into the direct electrochemical conversion of reactive carbons into electricity--with experimental evidence of total efficiencies exceeding 80% of the heat of combustion of carbon. Together with technologies for extraction of reactive carbons from broad based fossil fuels, direct carbon conversion addresses the objectives of DOE's ''21st Century Fuel Cell'' with exceptionally high efficiency (>70% based on
ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in ... more ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.
Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu)... more Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu). SrI2(Eu) has excellent material properties for gamma ray spectroscopy: high light yield (>80,000 ph/MeV), excellent light yield proportionality, and high effective atomic number (Z=49) for high photoelectric cross-section. Through advances in SrI2(Eu) crystal growth, high quality 1.5 inch and 2 inch diameter boules have been produced. In these large SrI2(Eu) crystals, optical light trapping by Eu 2+ degrades the energy resolution as measured by analog electronics, but we mitigate this effect through on-the-fly correction of the scintillation pulses by digital readout electronics. Using this digital pulse-processing technique we have demonstrated energy resolution of <3% FWHM at 662 keV for a 4 in 3 SrI2(Eu) crystal, over 2.6 inches long. With these digital readout electronics, we are developing a prototype handheld detector to demonstrate the radioisotope identification performan...
Environmental Science & Technology, 2003
Hard X-Ray and Gamma-Ray Detector Physics IX, 2007
Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with ... more Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with bialkali photomultiplier tube detection as good as 8.6% at 662 keV. Ceramic fabrication allows production of garnets that cannot easily be grown as single crystals, such as Gadolinium Aluminum Garnet and Terbium Aluminum Garnet. Measured scintillation light yields of Cerium-doped ceramic garnets indicate prospects for high energy resolution.
Fourteenth Annual Battery Conference on Applications and Advances. Proceedings of the Conference (Cat. No.99TH8371), 1999
Tetrahedron Letters, 1989
Journal of The Electrochemical Society, 2005
Journal of Colloid and Interface Science, 2005
The Journal of Chemical Physics, 1998
The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semi... more The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semiconductor quantum dots have been studied using femtosecond laser spectroscopy. The dynamics are obtained via excitation of the quantum dots with high power 390 nm pulses of 150 fs duration, and probing of the photoexcited species by monitoring the change in absorption at 790 nm as a
IEEE Transactions on Nuclear Science, 2000
Environmental Science & Technology, 2003
Crystal Research and Technology, 2013
ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in pa... more ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in particular cesium barium iodide (CBI), cesium calcium iodide (CCI) and barium bromine iodide (BBI), as well as report on their scintillation and optical properties. Double salt iodides inherently have high density and atomic number which translates to good stopping power for energetic particles, in particular gamma rays. Light yields of 54,000 ph/MeV for CBI, 51,000 ph/MeV for CCI, and 46,000 ph/MeV for BBI were measured. A FWHM energy resolution for the 662 keV full absorption peak was observed at 5.7% for CBI, 16.3% for CCI and 3.56% for BBI. The principal scintillation decay timing for CBI was 840 ns, 462 ns for BBI, and two distinct time components of 9 ns and 1900 ns were observed for CCI.
Applied Spectroscopy, 1992
We are conducting research into the direct electrochemical conversion of reactive carbons into el... more We are conducting research into the direct electrochemical conversion of reactive carbons into electricity--with experimental evidence of total efficiencies exceeding 80% of the heat of combustion of carbon. Together with technologies for extraction of reactive carbons from broad based fossil fuels, direct carbon conversion addresses the objectives of DOE&#39;s &#39;&#39;21st Century Fuel Cell&#39;&#39; with exceptionally high efficiency (&amp;gt;70% based on
ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in ... more ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.
Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu)... more Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu). SrI2(Eu) has excellent material properties for gamma ray spectroscopy: high light yield (>80,000 ph/MeV), excellent light yield proportionality, and high effective atomic number (Z=49) for high photoelectric cross-section. Through advances in SrI2(Eu) crystal growth, high quality 1.5 inch and 2 inch diameter boules have been produced. In these large SrI2(Eu) crystals, optical light trapping by Eu 2+ degrades the energy resolution as measured by analog electronics, but we mitigate this effect through on-the-fly correction of the scintillation pulses by digital readout electronics. Using this digital pulse-processing technique we have demonstrated energy resolution of <3% FWHM at 662 keV for a 4 in 3 SrI2(Eu) crystal, over 2.6 inches long. With these digital readout electronics, we are developing a prototype handheld detector to demonstrate the radioisotope identification performan...
Environmental Science & Technology, 2003
Hard X-Ray and Gamma-Ray Detector Physics IX, 2007
Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with ... more Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with bialkali photomultiplier tube detection as good as 8.6% at 662 keV. Ceramic fabrication allows production of garnets that cannot easily be grown as single crystals, such as Gadolinium Aluminum Garnet and Terbium Aluminum Garnet. Measured scintillation light yields of Cerium-doped ceramic garnets indicate prospects for high energy resolution.
Fourteenth Annual Battery Conference on Applications and Advances. Proceedings of the Conference (Cat. No.99TH8371), 1999
Tetrahedron Letters, 1989
Journal of The Electrochemical Society, 2005
Journal of Colloid and Interface Science, 2005
The Journal of Chemical Physics, 1998
The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semi... more The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semiconductor quantum dots have been studied using femtosecond laser spectroscopy. The dynamics are obtained via excitation of the quantum dots with high power 390 nm pulses of 150 fs duration, and probing of the photoexcited species by monitoring the change in absorption at 790 nm as a
IEEE Transactions on Nuclear Science, 2000
Environmental Science & Technology, 2003
Crystal Research and Technology, 2013
ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in pa... more ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in particular cesium barium iodide (CBI), cesium calcium iodide (CCI) and barium bromine iodide (BBI), as well as report on their scintillation and optical properties. Double salt iodides inherently have high density and atomic number which translates to good stopping power for energetic particles, in particular gamma rays. Light yields of 54,000 ph/MeV for CBI, 51,000 ph/MeV for CCI, and 46,000 ph/MeV for BBI were measured. A FWHM energy resolution for the 662 keV full absorption peak was observed at 5.7% for CBI, 16.3% for CCI and 3.56% for BBI. The principal scintillation decay timing for CBI was 840 ns, 462 ns for BBI, and two distinct time components of 9 ns and 1900 ns were observed for CCI.
Applied Spectroscopy, 1992