J. D. Bowman
Oak Ridge National Laboratory
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by J. D. Bowman.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2009
D. Pocanic; R. Alarcon; L.P. Alonzi; S. Baeßler; S. Balascuta; J. D. Bowman; M. Bychkov; J. Byrne; J. R. Calarco; V. Cianciolo; C. Crawford; E. Frlež; M. T. Gericke; G. L. Greene; R. Grzywacz; Vladimir Gudkov; F. W. Hersman; Andreas Klein; J. Martin; S. A. Page; A. Palladino; S. I. Penttilä; K. Rykaczewski; W. S. Wilburn; A. R. Young; G. R. Young
The Nab collaboration will perform a precise measurement of a, the electron-neutrino correlation parameter, and b, the Fierz interference term in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS, using a novel electric/magnetic field spectrometer and detector design. The experiment is aiming at the 10{sup -3} accuracy level in {Delta}a/a, and will provide an independent measurement of {lambda} = G{sub A}/G{sub V}, the ratio of axial-vector to vector coupling constants of the nucleon. Nab also plans to perform the first ever measurement of b in neutron decay, which will provide an independent limit on the tensor weak coupling.
Physical Review C | 2014
D. J. Salvat; E. R. Adamek; D. Barlow; J. D. Bowman; L. J. Broussard; Nathan Callahan; S. M. Clayton; C. Cude-Woods; S. Currie; E. B. Dees; W. Fox; P. Geltenbort; K. P. Hickerson; A. T. Holley; Chen-Yu Liu; M. Makela; J. Medina; D. J. Morley; C. L. Morris; S. I. Penttilä; J. Ramsey; A. Saunders; S. J. Seestrom; E. I. Sharapov; Sky Sjue; B. A. Slaughter; J. Vanderwerp; B. VornDick; P. L. Walstrom; Zhehui Wang
The UCN experiment is designed to measure the lifetime n of the free neutron by trapping ultracold neutrons (UCN) in a magneto-gravitational trap. An asymmetric bowl-shaped NdFeB magnet Halbach array confines low-field-seeking UCN within the apparatus, and a set of electromagnetic coils in a toroidal geometry provides a background holding field to eliminate depolarization-induced UCN loss caused by magnetic field nodes. We present a measurement of the storage time store of the trap by storing UCN for various times and counting the survivors. The data are consistent with a single exponential decay, and we find store = 860 19 s, within 1 of current global averages for n. The storage time with the holding field deactivated is found to be store = 470 160 s; this decreased storage time is due to the loss of UCN, which undergo Majorana spin flips while being stored. We discuss plans to increase the statistical sensitivity of the measurement and investigate potential systematic effects.
Physical Review B | 2015
K. B. Grammer; R. Alarcon; L. Barrón-Palos; D. Blyth; J. D. Bowman; J. Calarco; C. Crawford; K. Craycraft; D. Evans; N. Fomin; J. Fry; M. T. Gericke; R. C. Gillis; G. L. Greene; J. Hamblen; C. Hayes; S. Kucuker; R. Mahurin; M. Maldonado-Velázquez; E. Martin; M. McCrea; P.E. Mueller; M. Musgrave; H. Nann; S. I. Penttilä; W. M. Snow; Z. Tang; W. S. Wilburn
Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many-body physics. Unfortunately, the pair correlation function
Journal of Physics G | 2014
S. Baeßler; J. D. Bowman; S. I. Penttilä; D. Pocanic
g(r)
11TH CONFERENCE ON THE INTERSECTIONS OF PARTICLE AND NUCLEAR PHYSICS: (CIPANP 2012) | 2013
S. Baeßler; R. Alarcon; L.P. Alonzi; S. Balascuta; L. Barrón-Palos; J. D. Bowman; M. Bychkov; J. Byrne; J. R. Calarco; T. Chupp; T. V. Cianciolo; C. Crawford; E. Frlež; M. T. Gericke; F. Glück; G. L. Greene; R. Grzywacz; Vladimir Gudkov; D. Harrison; F. W. Hersman; T. Ito; M. Makela; J. Martin; P. L. McGaughey; S. McGovern; S. A. Page; S. I. Penttilä; D. Pocanic; K. Rykaczewski; A. Salas-Bacci
inferred from neutron scattering measurements of the differential cross section
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2017
L. J. Broussard; B. A. Zeck; E. R. Adamek; S. Baeßler; N. Birge; M. Blatnik; J. D. Bowman; Aaron Brandt; M. A. P. Brown; J. Burkhart; Nathan Callahan; Steven Clayton; C. Crawford; C. Cude-Woods; S. Currie; E. B. Dees; X. Ding; N. Fomin; E. Frlez; J. Fry; F. Gray; S. Hasan; K. P. Hickerson; J. Hoagland; A. T. Holley; Takeyasu M. Ito; Andreas Klein; Hengne Li; Ching Liu; M. Makela
frac{densuremath{sigma}}{densuremath{Omega}}
Journal of Physics: Conference Series | 2010
R. C. Gillis; R. Alarcon; Septimiu Balascuta; L. Barrón-Palos; J. D. Bowman; R. Carlini; W. Chen; T. E. Chupp; C. Crawford; S. Covrig; M. Dabaghyan; N. Fomin; S. J. Freedman; Thomas R. Gentile; M. T. Gericke; G. L. Greene; F. W. Hersman; T. Ino; G. L. Jones; B. Lauss; M. Leuschner; W. R. Lozowski; R. Mahurin; Y. Masuda; J. Mei; G. S. Mitchell; S. Muto; H. Nann; S. A. Page; S. I. Penttilä
from different measurements reported in the literature are inconsistent. We have measured the energy dependence of the total cross section and the scattering cross section for slow neutrons with energies between 0.43 and 16.1 meV on liquid hydrogen at 15.6 K (which is dominated by the parahydrogen component) using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. The relationship between the neutron transmission measurement we perform and the total cross section is unambiguous, and the energy range accesses length scales where the pair correlation function is rapidly varying. At 1 meV our measurement is a factor of 3 below the data from previous work. We present evidence that these previous measurements of the hydrogen cross section, which assumed that the equilibrium value for the ratio of orthohydrogen and parahydrogen has been reached in the target liquid, were in fact contaminated with an extra nonequilibrium component of orthohydrogen. Liquid parahydrogen is also a widely used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. We describe our measurements and compare them with previous work.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2018
M.M. Musgrave; S. Baeßler; S. Balascuta; L. Barrón-Palos; D. Blyth; J. D. Bowman; T.E. Chupp; V. Cianciolo; C. Crawford; K. Craycraft; N. Fomin; J. Fry; M. T. Gericke; R. C. Gillis; K. Grammer; G. L. Greene; J. Hamblen; C. Hayes; P. Huffman; C. Jiang; S. Kucuker; M. McCrea; P.E. Mueller; S. I. Penttilä; W. M. Snow; E. Tang; Z. Tang; X. Tong; W. S. Wilburn
Precision measurements in free neutron beta decay serve to determine the coupling constants of beta decay, and offer several stringent tests of the standard model. This study describes the free neutron beta decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and finally puts it into the context of other recent and planned measurements of neutron beta decay observables.
International Journal of Modern Physics: Conference Series | 2016
W. M. Snow; M. W. Ahmed; J. D. Bowman; Chris Crawford; Nadia Fomin; H. Gao; M. T. Gericke; Vladimir Gudkov; B. R. Holstein; C. R. Howell; P. R. Huffman; W. T. H. Van Oers; S. I. Penttilä; Y. K. Wu
Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2018
K.B. Grammer; D. Blyth; J. D. Bowman; N. Fomin; G. L. Greene; M. Musgrave; E. Tang; Zhaowen Tang
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 resolution of ∼3 keV FWHM, and rise time of ∼50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of β particles and recoil protons from neutron β decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments to determine the neutron β decay parameters B, a, and b.