John C. Ramsey

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M. P. Mendenhall,1 R. W. Pattie, Jr.,2 Y. Bagdasarova,3,4 D. B. Berguno,5 L. J. Broussard,6 R. Carr,1 S. Currie,3 X. Ding,5 B. W. Filippone,1 A. Garcı́a,4 P. Geltenbort,7 K. P. Hickerson,1,3 J. Hoagland,2 A. T. Holley,2,8 R. Hong,4 T. M. Ito,3 A. Knecht,4 C.-Y. Liu,8 J. L. Liu,1,9 M. Makela,3 R. R. Mammei,5 J. W. Martin,10 D. Melconian,11 S. D. Moore,2 C.(More)
In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates(More)
E. I. Sharapov, C. L. Morris, ∗ M. Makela, A. Saunders, Evan R. Adamek, L. J. Broussard, C. B. Cude-Woods, Deion E Fellers, Peter Geltenbort, M. Hartl, S. I. Hasan, K. P. Hickerson, G. Hogan, A. T. Holley, C. M. Lavelle, Chen-Yu Liu, M. P. Mendenhall, J. Ortiz, R. W. Pattie Jr., D. G. Phillips II, J. Ramsey, D. J. Salvat, S. J. Seestrom, E. Shaw, Sky Sjue,(More)
We describe a detection system designed for precise measurements of angular correlations in neutron β decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for β electron detection with energy thresholds below 10 keV, energy(More) Ito, T M, Ramsey, J C, Yao, W, Beck, D H, Cianciolo, V, Clayton, S M, Crawford, C, Currie, S A, Filippone, B W, Griffith, W C, Makela, M, Schmid, R, Seidel, G M, Tang, Z, Wagner, D et al. (2016) An apparatus for studying electrical breakdown in liquid helium at 0.4 K and testing electrode materials for the SNS nEDM experiment. Review(More)
A comprehensive study of the electroluminescence of four longwavelength microcavity devices with InAs/GaInAs quantum dot active regions emitting near 1.3 μm was conducted. The four molecular beam epitaxial grown samples with AlAs oxide aperture confinement layers were fabricated, characterized, and optically modeled. Optical power transmission of the(More)
E. I. Sharapov,1 C. L. Morris,2,* M. Makela,2 A. Saunders,2 Evan R. Adamek,3 L. J. Broussard,2 C. B. Cude-Woods,3 Deion E. Fellers,2 Peter Geltenbort,4 M. Hartl,2 S. I. Hasan,5 K. P. Hickerson,6 G. Hogan,2 A. T. Holley,3 C. M. Lavelle,7 Chen-Yu Liu,3 M. P. Mendenhall,6 J. Ortiz,2 R. W. Pattie, Jr.,8 D. G. Phillips, II,8 J. Ramsey,2 D. J. Salvat,3 S. J.(More)
A precise measurement of the neutron decay β asymmetry A₀ has been carried out using polarized ultracold neutrons from the pulsed spallation ultracold neutron source at the Los Alamos Neutron Science Center. Combining data obtained in 2008 and 2009, we report A₀ = -0.119 66±0.000 89{-0.001 40}{+0.001 23}, from which we determine the ratio of the(More)
B. Plaster,1,2 R. Rios,3,4 H. O. Back,5,6 T. J. Bowles,3 L. J. Broussard,6,7 R. Carr,2 S. Clayton,3 S. Currie,3 B. W. Filippone,2 A. Garcı́a,8 P. Geltenbort,9 K. P. Hickerson,2 J. Hoagland,5 G. E. Hogan,3 B. Hona,1 A. T. Holley,5 T. M. Ito,2,3 C.-Y. Liu,10 J. Liu,2,11 M. Makela,3 R. R. Mammei,12 J. W. Martin,2,13 D. Melconian,14 M. P. Mendenhall,2 C. L.(More)
M. P. Mendenhall, R. W. Pattie, Jr., Y. Bagdasarova, 4 D. B. Berguno, L. J. Broussard, R. Carr, S. Currie, X. Ding, B. W. Filippone, A. Garćıa, P. Geltenbort, K. P. Hickerson, 3 J. Hoagland, A. T. Holley, 8 R. Hong, T. M. Ito, A. Knecht, C.-Y. Liu, J. L. Liu, 9 M. Makela, R. R. Mammei, J. W. Martin, D. Melconian, S. D. Moore, C. L. Morris, A. Pérez Galván,(More)