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Search Results: 1 - 10 of 335065 matches for " R. B. Vogelaar "
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LENS as a Probe of Sterile Neutrino Mediated Oscillations
C. Grieb,J. M. Link,M. L. Pitt,R. S. Raghavan,D. Rountree,R. B. Vogelaar
Physics , 2007,
Abstract: Sterile neutrino ($\nu_s$) conversion in meter scale baselines can be sensitively probed using mono-energetic, sub-MeV, flavor pure $\nu_e$'s from an artificial MCi source and the unique technology of the LENS low energy solar $\nu_e$ detector. Active-sterile {\em oscillations} can be directly observed in the granular LENS detector itself to critically test and extend results of short baseline accelerator and reactor experiments.
Low-Background gamma counting at the Kimballton Underground Research Facility
P. Finnerty,S. MacMullin,H. O. Back,R. Henning,A. Long,K. T. Macon,J. Strain,R. M. Lindstrom,R. B. Vogelaar
Physics , 2010, DOI: 10.1016/j.nima.2011.03.064
Abstract: The next generation of low-background physics experiments will require the use of materials with unprecedented radio-purity. A gamma-counting facility at the Kimballton Underground Research Facility (KURF) has been commissioned to perform initial screening of materials for radioactivity primarily from nuclides in the 238U and 232Th decay chains, 40K and cosmic-ray induced isotopes. The facility consists of two commercial low-background high purity germanium (HPGe) detectors. A continuum background reduction better than a factor of 10 was achieved by going underground. This paper describes the facility, detector systems, analysis techniques and selected assay results.
A Study of the Residual 39Ar Content in Argon from Underground Sources
J. Xu,F. Calaprice,C. Galbiati,A. Goretti,G. Guray,T. Hohman,D. Holtz,A. Ianni,M. Laubenstein,B. Loer,C. Love,C. J. Martoff,D. Montanari,S. Mukhopadhyay,A. Nelson,S. D. Rountree,R. B. Vogelaar,A. Wright
Physics , 2012,
Abstract: The discovery of argon from underground sources with significantly less 39Ar than atmospheric argon was an important step in the development of direct-detection dark matter experiments using argon as the active target. We report on the design and operation of a low background detector with a single phase liquid argon target that was built to study the 39Ar content of the underground argon. Underground argon from the Kinder Morgan CO2 plant in Cortez, Colorado was determined to have less than 0.65% of the 39Ar activity in atmospheric argon.
Development of an isotropic optical light source for testing nuclear instruments
Zachary W. Yokley,S. Derek Rountree,R. Bruce Vogelaar
Physics , 2015,
Abstract: Nuclear instruments that require precise characterization and calibration of their optical components need well-characterized optical light sources with the desired wavelength, intensity, and directivity. This paper presents a novel technique for determining the performance of optical components by producing an isotropic-like source with a robotically positioned LED. The theory of operation for this light source, results of Monte Carlo validation studies, and experimental results are presented.
The Nylon Scintillator Containment Vessels for the Borexino Solar Neutrino Experiment
J. Benziger,L. Cadonati,F. Calaprice,E. de Haas,R. Fernholz,R. Ford,C. Galbiati,A. Goretti,E. Harding,An. Ianni,S. Kidner,M. Leung,F. Loeser,K. McCarty,A. Nelson,R. Parsells,A. Pocar,T. Shutt,A. Sonnenschein,R. B. Vogelaar
Physics , 2007, DOI: 10.1016/j.nima.2007.08.176
Abstract: Borexino is a solar neutrino experiment designed to observe the 0.86 MeV Be-7 neutrinos emitted in the pp cycle of the sun. Neutrinos will be detected by their elastic scattering on electrons in 100 tons of liquid scintillator. The neutrino event rate in the scintillator is expected to be low (~0.35 events per day per ton), and the signals will be at energies below 1.5 MeV, where background from natural radioactivity is prominent. Scintillation light produced by the recoil electrons is observed by an array of 2240 photomultiplier tubes. Because of the intrinsic radioactive contaminants in these PMTs, the liquid scintillator is shielded from them by a thick barrier of buffer fluid. A spherical vessel made of thin nylon film contains the scintillator, separating it from the surrounding buffer. The buffer region itself is divided into two concentric shells by a second nylon vessel in order to prevent inward diffusion of radon atoms. The radioactive background requirements for Borexino are challenging to meet, especially for the scintillator and these nylon vessels. Besides meeting requirements for low radioactivity, the nylon vessels must also satisfy requirements for mechanical, optical, and chemical properties. The present paper describes the research and development, construction, and installation of the nylon vessels for the Borexino experiment.
A new type of Neutrino Detector for Sterile Neutrino Search at Nuclear Reactors and Nuclear Nonproliferation Applications
C. Lane,S. M. Usman,J. Blackmon,C. Rasco,H. P. Mumm,D. Markoff,G. R. Jocher,R. Dorrill,M. Duvall,J. G. Learned,V. Li,J. Maricic,S. Matsuno,R. Milincic,S. Negrashov,M. Sakai,M. Rosen,G. Varner,P. Huber,M. L. Pitt,S. D. Rountree,R. B. Vogelaar,T. Wright,Z. Yokley
Physics , 2015,
Abstract: We describe a new detector, called NuLat, to study electron anti-neutrinos a few meters from a nuclear reactor, and search for anomalous neutrino oscillations. Such oscillations could be caused by sterile neutrinos, and might explain the "Reactor Antineutrino Anomaly". NuLat, is made possible by a natural synergy between the miniTimeCube and mini-LENS programs described in this paper. It features a "Raghavan Optical Lattice" (ROL) consisting of 3375 boron or $^6$Li loaded plastic scintillator cubical cells 6.3\,cm (2.500") on a side. Cell boundaries have a 0.127\,mm (0.005") air gap, resulting in total internal reflection guiding most of the light down the 3 cardinal directions. The ROL detector technology for NuLat gives excellent spatial and energy resolution and allows for in-depth event topology studies. These features allow us to discern inverse beta decay (IBD) signals and the putative oscillation pattern, even in the presence of other backgrounds. We discuss here test venues, efficiency, sensitivity and project status.
Demonstration of a solid deuterium source of ultra-cold neutrons
A. Saunders,J. M. Anaya,T. J. Bowles,B. W. Filippone,P. Geltenbort,R. E. Hill,M. Hino,S. Hoedl,G. E. Hogan,T. M. Ito,K. W. Jones,T. Kawai,K. Kirch,S. K. Lamoreaux,C. -Y. Liu,M. Makela,L. J. Marek,J. W. Martin,C. L. Morris,R. N. Mortensen,A. Pichlmaier,S. J. Seestrom,A. Serebrov,D. Smith,W. Teasdale,B. Tipton,R. B. Vogelaar,A. R. Young,J. Yuan
Physics , 2003, DOI: 10.1016/j.physletb.2004.04.048
Abstract: Ultra-cold neutrons (UCN), neutrons with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role in measurements of fundamental properties of the neutron. The ability to manipulate UCN with material guides and bottles, magnetic fields, and gravity can lead to experiments with lower systematic errors than have been obtained in experiments with cold neutron beams. The UCN densities provided by existing reactor sources limit these experiments. The promise of much higher densities from solid deuterium sources has led to proposed facilities coupled to both reactor and spallation neutron sources. In this paper we report on the performance of a prototype spallation neutron-driven solid deuterium source. This source produced bottled UCN densities of 145 +/-7 UCN/cm3, about three times greater than the largest bottled UCN densities previously reported. These results indicate that a production UCN source with substantially higher densities should be possible.
The Physics and Nuclear Nonproliferation Goals of WATCHMAN: A WAter CHerenkov Monitor for ANtineutrinos
M. Askins,M. Bergevin,A. Bernstein,S. Dazeley,S. T. Dye,T. Handler,A. Hatzikoutelis,D. Hellfeld,P. Jaffke,Y. Kamyshkov,B. J. Land,J. G. Learned,P. Marleau,C. Mauger,G. D. Orebi Gann,C. Roecker,S. D. Rountree,T. M. Shokair,M. B. Smy,R. Svoboda,M. Sweany,M. R. Vagins,K. A. van Bibber,R. B. Vogelaar,M. J. Wetstein,M. Yeh
Physics , 2015,
Abstract: This article describes the physics and nonproliferation goals of WATCHMAN, the WAter Cherenkov Monitor for ANtineutrinos. The baseline WATCHMAN design is a kiloton scale gadolinium-doped (Gd) light water Cherenkov detector, placed 13 kilometers from a civil nuclear reactor in the United States. In its first deployment phase, WATCHMAN will be used to remotely detect a change in the operational status of the reactor, providing a first- ever demonstration of the potential of large Gd-doped water detectors for remote reactor monitoring for future international nuclear nonproliferation applications. During its first phase, the detector will provide a critical large-scale test of the ability to tag neutrons and thus distinguish low energy electron neutrinos and antineutrinos. This would make WATCHMAN the only detector capable of providing both direction and flavor identification of supernova neutrinos. It would also be the third largest supernova detector, and the largest underground in the western hemisphere. In a follow-on phase incorporating the IsoDAR neutrino beam, the detector would have world-class sensitivity to sterile neutrino signatures and to non-standard electroweak interactions (NSI). WATCHMAN will also be a major, U.S. based integration platform for a host of technologies relevant for the Long-Baseline Neutrino Facility (LBNF) and other future large detectors. This white paper describes the WATCHMAN conceptual design,and presents the results of detailed simulations of sensitivity for the project's nonproliferation and physics goals. It also describes the advanced technologies to be used in WATCHMAN, including high quantum efficiency photomultipliers, Water-Based Liquid Scintillator (WbLS), picosecond light sensors such as the Large Area Picosecond Photo Detector (LAPPD), and advanced pattern recognition and particle identification methods.
Precision Measurement of the Neutron Beta-Decay Asymmetry
M. P. Mendenhall,R. W. Pattie Jr,Y. Bagdasarova,D. B. Berguno,L. J. Broussard,R. Carr,S. Currie,X. Ding,B. W. Filippone,A. García,P. Geltenbort,K. P. Hickerson,J. Hoagland,A. T. Holley,R. Hong,T. M. Ito,A. Knecht,C. -Y. Liu,J. L. Liu,M. Makela,R. R. Mammei,J. W. Martin,D. Melconian,S. D. Moore,C. L. Morris,A. Pérez Galván,R. Picker,M. L. Pitt,B. Plaster,J. C. Ramsey,R. Rios,A. Saunders,S. J. Seestrom,E. I. Sharapov,W. E. Sondheim,E. Tatar,R. B. Vogelaar,B. VornDick,C. Wrede,A. R. Young,B. A. Zeck
Physics , 2012, DOI: 10.1103/PhysRevC.87.032501
Abstract: A new measurement of the neutron $\beta$-decay asymmetry $A_0$ has been carried out by the UCNA collaboration using polarized ultracold neutrons (UCN) from the solid deuterium UCN source at the Los Alamos Neutron Science Center (LANSCE). Improvements in the experiment have led to reductions in both statistical and systematic uncertainties leading to $A_0 = -0.11954(55)_{\rm stat.}(98)_{\rm syst.}$, corresponding to the ratio of axial-vector to vector coupling $\lambda \equiv g_A/g_V = -1.2756(30)$.
Determination of the Axial-Vector Weak Coupling Constant with Ultracold Neutrons
UCNA Collaboration,J. Liu,M. P. Mendenhall,A. T. Holley,H. O. Back,T. J. Bowles,L. J. Broussard,R. Carr,S. Clayton,S. Currie,B. W. Filippone,A. Garcia,P. Geltenbort,K. P. Hickerson,J. Hoagland,G. E. Hogan,B. Hona,T. M. Ito,C. -Y. Liu,M. Makela,R. R. Mammei,J. W. Martin,D. Melconian,C. L. Morris,R. W. Pattie Jr.,A. Perez Galvan,M. L. Pitt,B. Plaster,J. C. Ramsey,R. Rios,R. Russell,A. Saunders,S. J. Seestrom,W. E. Sondheim,E. Tatar,R. B. Vogelaar,B. VornDick,C. Wrede,H. Yan,A. R. Young
Physics , 2010, DOI: 10.1103/PhysRevLett.105.181803
Abstract: A precise measurement of the neutron decay $\beta$-asymmetry $A_0$ has been carried out using polarized ultracold neutrons (UCN) from the pulsed spallation UCN source at the Los Alamos Neutron Science Center (LANSCE). Combining data obtained in 2008 and 2009, we report $A_0 = -0.11966 \pm 0.00089_{-0.00140}^{+0.00123}$, from which we determine the ratio of the axial-vector to vector weak coupling of the nucleon $g_A/g_V = -1.27590_{-0.00445}^{+0.00409}$.
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