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Search Publications by: Kevin J. Coakley (Fed)

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Displaying 51 - 75 of 91

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)

Nonlinear Modeling of Tunnel Diode Detectors

September 24, 2004
Author(s)
Dave K. Walker, Kevin Coakley, Jolene Splett
We investigate the sensitivity and nonlinear properties of a tunnel diode microwave detector as functions of the input power and the load impedance presented at the detector's output. We compare the two-tone method estimate of nonlinearity with precise

Chaotic Scattering and Escape Times of Marginally Trapped Ultracold Neutrons

April 1, 2004
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)

Adaptive Characterization of Jitter Noise in Sampled High-Speed Signals

October 1, 2003
Author(s)
Kevin J. Coakley, Chih-Ming Wang, Paul D. Hale, Tracy S. Clement
We estimate the root-mean-square (RMS) value of timing jitter noise in simulated signals similar to measured high-speed sampled signals. The simulated signals are contaminated by additive noise, timing jitter noise, and time shift errors. Before estimating

Erratum: Modeling Detector Response for Neutron Depth Profiling

August 10, 2003
Author(s)
Kevin Coakley, R. G. Downing, George P. Lamaze, H C. Hofsass, C Ronning, J Biegel
In a previous paper, we analyzed the Neutron Depth Profiling energy spectrum collected from a diamond-like carbon (DLC) sample doped with boron. Based on a numerical model for the Detector Response Function (DRF), we estimated a theoretical boron profile

Spatial Methods for Event Reconstruction in CLEAN

April 9, 2003
Author(s)
Kevin Coakley, D N. Mckinsey
In CLEAN (Cryogenic Low Energy Astrophysics with Noble gases), a proposed neutrino and dark matter detector, background discrimination is possible if one can determine the location of an event with high accuracy. Here, we develop spatial methods for event

Estimation of Q-factors and Resonant Factors

March 1, 2003
Author(s)
Kevin Coakley, Jolene Splett, Michael D. Janezic, Raian K. Kaiser
We estimate the quality factor Q and resonant frequency f 0 of a microwave cavity based on resonance curve observations on an equally-spaced frequency grid. The observed resonance curve is the squared magnitude of an observed complex scattering parameter

Estimation of Q-Factors and Resonant Frequencies

March 1, 2003
Author(s)
Kevin J. Coakley, Jolene D. Splett, Michael D. Janezic, R F. Kaiser
We estimate the quality factor Q and resonant frequency f o of a microwave cavity based on resonance curve observations on an equally-spaced frequency grid. The observed resonance curve is the squared magnitude of an observed complex scattering parameter

Estimation of Neutron Mean Wavelength From Rocking Curve Data

January 1, 2003
Author(s)
Kevin J. Coakley, Z Chowdhuri, W M. Snow, J M. Richardson, Maynard S. Dewey
At NIST, an in-beam neutron lifetime experiment is underway. In part of the experiment, a neutron detector is calibrated. The accuracy of the detector calibration depends, in part, on how accurately the mean wavelength of a neutron beam can be estimated

Calibration of a Stopping Power Model for Silicon Based on Analysis of Neutron Depth Profiling and Secondary Ion Mass Spectrometry Measurements

June 1, 2002
Author(s)
Kevin J. Coakley, Huaiyu H. Chen-Mayer, George P. Lamaze, David S. Simons, P E. Thompson
We measure the boron concentration versus depth profile within a silicon sample with four delta-doped planes by secondary ion mass spectrometry. In a neutron depth profiling (NDP) experiment, we illuminate the sample with a neutron beam. Nuclear reactions