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Search Publications by: Kevin J. Coakley (Fed)

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Displaying 101 - 125 of 183

Prospects for a New Cold Neutron Beam Measurement of the Neutron Lifetime

October 5, 2009
Author(s)
Maynard S. Dewey, Kevin J. Coakley, David M. Gilliam, G. Greene, A. Laptev, Jeffrey S. Nico, William M. Snow, F. E. Wiefeldt, A. Yue
In the most accurate cold neutron beam determination of the neutron lifetime based on the absolute counting of decay protons, the largest uncertainty was attributed to the absolute determination of the capture flux of the cold neutron beam. Currently an

Pulse Shape Discrimination for a Fast Neutron Detector

February 9, 2009
Author(s)
Kevin J. Coakley, Dominic F. Vecchia, Jeffrey S. Nico, B Fisher
We are developing a detector that uses liquid scintillator loaded with Li-6 for the efficient measurement of fast neutrons and their energy. Such a detector would have both scientific applications such as quantification of neutron energy spectra in

Radiative Beta Decay of the Free Neutron

February 2, 2009
Author(s)
R L. Cooper, T E. Chupp, Maynard S. Dewey, Thomas R. Gentile, Hans Pieter Mumm, Jeffrey S. Nico, Alan Keith Thompson, B M. Fisher, I Kremsky, F E. Wietfeldt, E J. Beise, H Breuer, K G. Kiriluk, J Bryne, Kevin Coakley, Changbo Fu
The theory of quantum electrodynamics predicts that the beta decay of the neutron into a proton, electron, and antineutrino is accompanied by a continuous spectrum of emitted photons described as inner bremsstrahlung. While this phenomenon has been

Statistical Learning Methods for Neutron Transmission Tomography of Fuel Cells

July 8, 2008
Author(s)
Kevin Coakley, Dominic F. Vecchia, Daniel S. Hussey
In a fuel cell, water is formed as a by-product of the reaction between hydrogen and oxygen. As a neutron beam passes through a fuel cell, it can undergo s-wave scattering. For the dry and wet states of a fuel cell, there are spatially varying neutron

Development of the Aerosol Particle Mass Analyzer

October 17, 2007
Author(s)
Nobuhiko Fukushima, Naoko Tajima, Kensei Ehara, Hiromu Sakurai, Kevin Coakley
The Aerosol Particle Mass Analyzer (APM), can classify particles according to their mass-to-charge ratio. The utility of the APM has been confirmed; the APM has been applied to atmospheric aerosol research and engine exhaust measurements. The operating

Optimal Ion Trapping Experiment

May 10, 2007
Author(s)
Kevin J. Coakley
In each run of an experiment, ions are confined in a trap for duration {\tau}. After the trapping stage, ions are purged and detected. The detector provides incomplete information because it goes dead after detecting the first trapped ion. There is a dead

Feasibility of Coded Source Neutron Transmission Tomography

January 1, 2007
Author(s)
Kevin Coakley, Daniel S. Hussey
In a simulation experiment, we study the feasibility of coded source neutron transmission tomography for imaging water density in fuel cells at the NIST neutron imaging facility. In standard two-dimensional transmission tomography, one reconstructs a

Stochastic Modeling and Estimation in a Neutron Lifetime Experiment

January 1, 2007
Author(s)
Yang G. L., Kevin Coakley
A team of researchers demonstrated at the National Institute of Standards and Technology Cold Neutron Research Facility for the first time that ultra cold neutrons can be confined in a magnetic trap filled with liquid helium. This technical breakthrough

Observation of the Radiative Decay Mode of the Free Neutron

December 29, 2006
Author(s)
Jeffrey S. Nico, Maynard S. Dewey, Thomas R. Gentile, Hans P. Mumm, Alan K. Thompson, B Fisher, I Kremsky, Fred E. Wietfeldt, T E. Chupp, R Cooper, E Beise, K G. Kiriluk, J Byrne, Kevin J. Coakley
The theory of quantum electrodynamics predicts that beta decay of the neutron into a proton, electron, and antineutrino should be accompanied by a continuous spectrum of soft photons. While this inner bremsstrahlung branch has been previously measured in

Progress Towards a Precision Measurement of the Neutron Lifetime Using Magnetically Trapped Ultracold Neutrons

January 1, 2006
Author(s)
P.-N. Seo, Kevin Coakley, J M. Doyle, F H. DuBose, R Golub, E Korobkina, S K. Lamoreaux, Hans Pieter Mumm, C M. O'Shaughnessy, G R. Palmquis, A K. Thompson, Grace L. Yang, L Yang, Paul R. Huffman
As part of an on-going program utilizing magnetically trapped ultracold neutrons (UCNs,) we are developing a technique that offers the possibility of improving the precision of the neutron lifetime by more than an order of magnitude. The experiment works

Relative Permittivity and Loss Tangent Measurement Using the NIST 60 mm Cylindrical Cavity

August 31, 2005
Author(s)
Michael D. Janezic, Jolene D. Splett, Kevin J. Coakley, Raian K. Kaiser, John H. Grosvenor Jr
In order to develop a dielectric Standard Reference Material (SRM), a measurement system for measuring the relative permittivity and loss tangent of dielectric materials is presented. To achieve the necessary level of measurement accuracy, we selected the

Chaotic Scattering and Escape Times of Marginally Trapped Ultracold Neutrons

July 1, 2005
Author(s)
Kevin Coakley, J M. Doyle, S N. Dzhosyuk, L Yang, Paul R. Huffman
We compute classical trajectories of ultracold neutrons (UCNs) in a superconducting Ioffe-type magnetic trap using a symplectic integration method. We find that the computed escape time for a particular set of initial conditions (momentum and position)