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Search Publications by: Kevin J. Coakley (Fed)

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Displaying 26 - 50 of 93

Near-field control and imaging of free charge carrier variations in GaN nanowires

February 15, 2016
Author(s)
Samuel Berweger, Paul T. Blanchard, Matthew Brubaker, Kevin J. Coakley, Norman A. Sanford, Thomas Mitchell (Mitch) Wallis, Kris A. Bertness, Pavel Kabos
Despite their uniform crystallinity, the shape and faceting of semiconducting nanowires (NWs) can give rise to variations in structure and associated electronic properties. Here we investigate local variations in electronic structure across individual n

Survival analysis approach to account for non-exponential decay rate effects in lifetime experiments

January 13, 2016
Author(s)
Kevin J. Coakley, Maynard S. Dewey, Michael G. Huber, Hans P. Mumm, Alan Keith Thompson, Andrew T. Yue, C. R. Huffer, P. R. Huffman, C. M. O'Shaughnessy, K. W. Schelhammer, D. E. Marley
In experiments that measure the lifetime of trapped particles, in addition to loss mechanisms with exponential survival probability functions, particles can be lost by mechanisms with non-exponential survival probability functions. Failure to account for

A strong loophole-free test of local realism

December 16, 2015
Author(s)
Lynden K. Shalm, Evan Meyer-Scott, B. G. Christensen, Peter L. Bierhorst, Michael A. Wayne, Deny Hamel, Martin J. Stevens, Thomas Gerrits, Scott C. Glancy, Michael S. Allman, Kevin J. Coakley, Shellee D. Dyer, Adriana E. Lita, Varun B. Verma, Joshua C. Bienfang, Alan L. Migdall, Yanbao Zhang, William Farr, Francesco Marsili, Matthew D. Shaw, Jeffrey Stern, Carlos Abellan, Waldimar Amaya, Valerio Pruneri, Thomas Jennewein, Morgan Mitchell, P. G. Kwiat, Richard P. Mirin, Emanuel H. Knill, Sae Woo Nam
We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high

Update on the MiniCLEAN Dark Matter Experiment

March 24, 2015
Author(s)
Kevin J. Coakley, K. Rielage, M. Akashi-Ronquest, M. Bodmer, R. Bourque, B. Buck, A. Butcher, T. Caldwell, Y. Chen, F. A. Duncan, E. Flores, J. A. Formaggio, D. Glaster, F. Giuliani, M. Gold, E. Grace, J. Griego, N. Guerrero, V. Guiseppe, R. Henning, A. Hime, S. Jaditz, C. Kachulis, E. Kearns, J. Kelsey, J. R. Klein, A. Latorre, I. Lawson, O. Li, P. Liimatainen, S. Linden, F. Lopez, K. McFarlane, D. N. McKinsey, S. MacMullin, A. Mastbaum, D.-M. Mei, J. Monroe, J. A. Nikkel, J. Oertel, G. D. Orebi Gann, K. Palladino, G. Perumpilly, L. Rodriguez, R. Schnee, S. Seibert, J. Walding, B. Wang, J. Wang, C. Zhang
The direct search for dark matter is entering a period of increased sensitivity to the hypothetical Weakly Interacting Massive Particle (WIMP). One such technology that is being examined is a scintillationonly noble liquid experiment, MiniCLEAN. MiniCLEAN

Analysis of coincidence-time loopholes in experimental Bell tests

March 4, 2015
Author(s)
B. G. Christensen, A. Hill, P. G. Kwiat, Emanuel Knill, Sae Woo Nam, Kevin Coakley, Scott Glancy, Krister Shalm, Y. Zhang
We apply a distance-based Bell-test analysis method ["Bell inequalities for continuously emitting sources" E. Knill et al. arXiv:14097732 (2014)] to three experimental data sets where conventional analyses failed or required additional assumptions. The

Bell Inequalities for Continuously Emitting Sources

March 4, 2015
Author(s)
Emanuel H. Knill, Scott C. Glancy, Sae Woo Nam, Kevin J. Coakley, Yanbao Zhang
A common experimental strategy for demonstrating non-classical correlations is to show violation of a Bell inequality by measuring a continuously emitted stream of entangled photon pairs. The measurements involve the detection of photons by two spatially

Improving Photoelectron Counting and Particle Identification in Scintillation Detectors with Bayesian Techniques

December 19, 2014
Author(s)
Kevin J. Coakley, M. Akashi-Ronquest, P.-A. Amaudruz, B. Beltran, M. Bodmer, M.G. Boulay, R. Bourque, B. Buck, A. Butcher, B. Cai, T. Caldwell, M. Chen, Y. Chen, B. Cleveland, F. A. Duncan, E. O'Dwyer, E. Flores, J. A. Formaggio, D. Gastler, F. Giuliani, M. Gold, V. V. Golovko, P. Gore, K. Graham, E. Grace, J. Griego, N. Guerrero, V. Guiseppe, A. L. Hallin, P. Harvey, R. Henning, A, Hime, J. Hofgartner, S. Jaditz, C. J. Jillings, C. Kachulis, E. Kearns, J. Kelsey, J. R. Klein, M. Ku'zniak, A. Latorre, L. Lawson, O. Li, J. J. Lidgard, P. Liimatainen, S. Linden, W. H. Lippincott, F. Lopez, K. McFarlane, R. Mathew, A. B. McDonald, D.-M Mei, J. Monroe, A. Muir, C. Nantais, J. A. Nikkel, J. Oertel, K. Olsen, G. D. Orebi Gann, C. Oullet, K. Palladino, P. Pasuthip, G. Perumpilly, T. Pollmann, W. Rau, F. Reti'ere, L. Rodriguez, R. Schnee, S. Seibert, P. Skensved, T. Sonley, E. V'azquez Ja' uregui, J. Walding, B. Wang
Many current and future dark matter and neutrino detectors are designed to record scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on

Nonproportionality in the scintillation light yield of bismuth germanate

November 11, 2014
Author(s)
Thomas R. Gentile, M J. Bales, H Breuer, T E. Chupp, Kevin J. Coakley, R L. Cooper, Jeffrey S. Nico, B. O'Neill
We present measurements of nonproportionality in the scintillation light yield of bismuth germanate (BGO) for gamma-rays with energies between 6 keV and 662 keV. The scintillation light was read out by avalanche photodiodes (APDs) with both the BGO

Detection of Hazardous Liquids using Microwave

September 24, 2014
Author(s)
Michael D. Janezic, Jolene D. Splett, Kevin J. Coakley, James R. Baker-Jarvis
The primary objective of this study is to determine the feasibility of using low-power microwaves to distinguish between hazardous and non-hazardous liquids at security checkpoints. According to the 2008 High-Priority Technology Needs, a report published

Imaging the p-n junction in a gallium nitride nanowire with a scanning microwave microscope

July 2, 2014
Author(s)
Atif A. Imtiaz, Thomas M. Wallis, Joel C. Weber, Kevin J. Coakley, Matthew D. Brubaker, Paul T. Blanchard, Kristine A. Bertness, Norman A. Sanford
We used a broadband, atomic-force-microscope-based, scanning microwave microscope (AFM-SMM) to probe the axial dependence of the depletion in a GaN nanowire (NW) p-n junction structure. The NWs were c-axis oriented and grown by molecular beam epitaxy. The

Stochastic Modeling and Simulation of Marginally Trapped Neutrons

May 20, 2014
Author(s)
Kevin J. Coakley
For a magnetic trapping experiment, I present an efficient method for simulating experimental beta −decay rates which accounts for loss of marginally trapped neutrons due to wall collisions and other possible loss mechanisms. Monte Carlo estimates of time

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons

May 1, 2014
Author(s)
Hans P. Mumm, Alan Keith Thompson, Paul R. Huffman, Christopher O'Shaughnessy, Kevin J. Coakley, Robert Golub, John M. Doyle, Steve K. Lamoreaux, P.-N. Seo, C E. Mattoni, S N. Dzhosyuk, L Yang, Grace L. Yang, Karl W. Schelhammer, Christopher M. Swank
The neutron beta-decay lifetime plays an important role, both in understanding weak interactions within the framework of the Standard Model, and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we

Gallium Nitride Nanowire Probe for Near-Field Scanning Microwave Microscopy

January 15, 2014
Author(s)
Joel C. Weber, Paul T. Blanchard, Aric W. Sanders, Atif A. Imtiaz, Thomas M. Wallis, Kevin J. Coakley, Kristine A. Bertness, Pavel Kabos, Norman A. Sanford, Victor M. Bright
We report on the fabrication of a GaN nanowire probe for near-field scanning microwave microscopy. A single nanowire was Pt-bonded to a commercial Si cantilever prior to evaporation of a Ti/Al coating to provide a microwave signal pathway. Testing over a

Improving quantitative neutron radiography through image restoration

July 20, 2013
Author(s)
Daniel S. Hussey, Elias M. Baltic, Kevin J. Coakley, David L. Jacobson
This in-situ study examines the water content in polymer electrolyte fuel cells (PEFCs) using neutron radiography. Various conditions such as different polytetraflouroethylene (PTFE) loadings in the gas diffusion media including the micro-porous layer (MPL

Scintillation Yield and Time Dependence from Electronic and Nuclear Recoils in Liquid Neon

August 13, 2012
Author(s)
Kevin J. Coakley, W. H. Lippincott, D. Gastler, E. Kearns, D. N. McKinsey, J. A. Nikkel
We have performed measurements of scintillation light in liquid neon, observing a signal yield in our detector as high as (3.5 +/- 0.04) photoelectrons/keV. We measure pulse shape discrimination between electronic and nuclear recoils in liquid neon between

A near-field scanning microwave microscope for characterization of inhomogeneous photovoltaics

August 10, 2012
Author(s)
Joel C. Weber, Kristine A. Bertness, John B. Schlager, Norman A. Sanford, Atif A. Imtiaz, Thomas M. Wallis, Pavel Kabos, Kevin J. Coakley, Victor Bright, Lorelle M. Mansfield
We present a near field scanning microwave microscope (NSMM) optimized for imaging photovoltaic samples. Our system incorporates a cut Pt-Ir tip inserted into an open ended coaxial cable to form a weak resonator, allowing the microwave reflection S11

A gamma and X-ray dector for cryogenic, high magnetic field applications

July 13, 2012
Author(s)
Thomas R. Gentile, R L. Cooper, R. Alarcon, M J. Bales, E J. Beise, H Breuer, J. Byrne, T E. Chupp, Kevin J. Coakley, Maynard S. Dewey, Changbo Fu, Hans P. Mumm, Jeffrey S. Nico, B. O'Neill, K. Pulliam, Alan Keith Thompson, F E. Wietfeldt
As part of an experiment to measure the spectrum of photons emitted in beta-decay of the free neu- tron, we developed and operated a detector consisting of 12 bismuth germanate (BGO) crystals coupled to avalanche photodiodes (APDs). The detector was

Fast Neutron Detection with Li-6-loaded Liquid Scintillator

April 12, 2011
Author(s)
David M. Gilliam, B Fisher, J N. Abdurashitov, Kevin Coakley, V N. Gavrin, Jeffrey S. Nico, A A. Shikhin, Alan Keith Thompson, Dominic F. Vecchia, V E. Yants
We report on the development of a fast neutron detector using a liquid scintillator doped with enriched 6Li. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene based liquid scintillator. A 6Li

Erratum: Scintillation time dependence and pulse shape discrimination in liquid argon

March 2, 2010
Author(s)
W. H. Lippincott, Kevin Coakley, D. Gastler, A. Hime, E. Kearns, D. N. McKinsey, J. A. Nikkel, L.C. Stonehill
We have found an error in the code used to perform the multibin method analysis of Sec. III C in which events were compared to a template trace calculated from the wrong photoelectron bin (the index l in Eqs. (14) and (15) did not match the observed signal

Scintillation time dependence and pulse shape discrimination in liquid argon

March 2, 2010
Author(s)
W. H. Lippincott, Kevin Coakley, D. Gastler, A. Hime, E. Kearns, D. N. McKinsey, J. A. Nikkel, L. C. Stonehill
Using a single-phase liquid argon detector with a signal yield of 4.85 photoelectrons per keV of electronic-equivalent recoil energy (keVee), we measure the scintillation time dependence of both electronic and nuclear recoils in liquid argon down to 5