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Search Results: 1 - 10 of 401281 matches for " M. Bergevin "
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A potential sterile neutrino search utilizing spectral distortion in a two-reactor/one-detector configuration
M. Bergevin,C. Grant,R. Svoboda
Physics , 2013,
Abstract: There is an observed deficit of about 6\% in the expected rate of anti-neutrino interactions when averaging over many different reactor experiments. While the significance of the deficit is low (98.6 \% CL), there is speculation that a non-interacting "sterile" neutrino could be the cause. In this paper we explore the possibility of a two-reactor/one-detector experiment at intermediate distances (100-500 meters) to look for a sterile neutrino in the mass range implied by this deficit. A method for probing $\Delta m^2$ phase space is developed using interference patterns between two oscillated spectra at different baselines. This method is used to investigate the potential sensitivity of the Double Chooz experiment, which has a single Near Detector at distances of 351 m and 465 m from two reactors of identical design. We conclude that Double Chooz could investigate sterile neutrino in the $\Delta m^{2}$ range of 0.002 to 0.5 eV$^2$ over 5 years of near detector running.
Towards Improving the Integration of Undergraduate Biology and Mathematics Education
Christopher Bergevin
Journal of Microbiology & Biology Education , 2010, DOI: 10.1128/jmbe.v11i1.134
Abstract: Arguments have recently asserted the need for change in undergraduate biology education, particularly with regard to the role of mathematics. The crux of these protests is that rapidly developing technology is expanding the types of measurements and subsequent data available to biologists. Thus future generations of biologists will require a set of quantitative and analytic skills that will allow them to handle these types of data in order to tackle relevant questions of interest. In this spirit, we describe here strategies (or lessons learned) for undergraduate educators with regard to better preparing undergraduate biology majors for the new types of challenges that lay ahead. The topics covered here span a broad range, from classroom approaches to the administrative level (e.g., fostering inter-departmental communication, student advising) and beyond. A key theme here is the need for an attitude shift with regard to mathematics education by both students and faculty alike. Such a shift will facilitate the development and implementation of new teaching strategies with regard to improving integration of mathematics and biology pedagogy.
Le Corps et l’Esprit : une épistémologie contrastée au ZhuangZi
Gabriel Bergevin-Estable
Phares : Revue Philosophique étudiante de l’Université Laval , 2009,
Abstract:
A search for cosmogenic production of $β$-neutron emitting radionuclides in water
S. Dazeley,M. Askins,M. Bergevin,A. Bernstein,N. S. Bowden,P. Jaffke,S. D. Rountree,T. M. Shokair,M. Sweany
Physics , 2015,
Abstract: Here we present the first results of WATCHBOY, a water Cherenkov detector designed to measure the yield of $\beta$-neutron emitting radionuclides produced by cosmic ray muons in water. In addition to the $\beta$-neutron measurement, we also provide a first look at isolating single-$\beta$ producing radionuclides following showering muons as a check of the detection capabilities of WATCHBOY. The data taken over $207$ live days indicates a $^{9}$Li production yield upper limit of $1.9\times10^{-7}\mu^{-1}g^{-1}\mathrm{cm}^2$ at $\sim400$ meters water equivalent (m.w.e.) overburden at the $90\%$ confidence level. In this work the $^{9}$Li signal in WATCHBOY was used as a proxy for the combined search for $^{9}$Li and $^{8}$He production. This result will provide a constraint on estimates of antineutrino-like backgrounds in future water-based antineutrino detectors.
Electric field control of multiferroic domains in Ni$_3$V$_2$O$_8$ imaged by X-ray polarization enhanced topography
F. Fabrizi,H. C. Walker,L. Paolasini,F. de Bergevin,T. Fennell,N. Rogado,R. J. Cava,Th. Wolf,M. Kenzelmann,D. F. McMorrow
Physics , 2010, DOI: 10.1103/PhysRevB.82.024434
Abstract: The magnetic structure of multiferroic Ni$_3$V$_2$O$_8$ has been investigated using non-resonant X-ray magnetic scattering. Incident circularly polarized X-rays combined with full polarization analysis of the scattered beam is shown to yield high sensitivity to the components of the cycloidal magnetic order, including their relative phases. New information on the magnetic structure in the ferroelectric phase is obtained, where it is found that the magnetic moments on the "cross-tie" sites are quenched relative to those on the "spine" sites. This implies that the onset of ferroelectricity is associated mainly with spine site magnetic order. We also demonstrate that our technique enables the imaging of multiferroic domains through polarization enhanced topography. This approach is used to image the domains as the sample is cycled by an electric field through its hysteresis loop, revealing the gradual switching of domains without nucleation.
Cd-doping effects in Ce2MIn8 (M = Rh and Ir) heavy fermion compounds
C. Adriano,C. Giles,E. M. Bittar,L. N. Coelho,F. de Bergevin,C. Mazzoli,L. Paolasini,W. Ratcliff,R. Bindel,J. W. Lynn,Z. Fisk,P. G. Pagliuso
Physics , 2009, DOI: 10.1103/PhysRevB.81.245115
Abstract: Low temperature magnetic properties of Cd-doped Ce2MIn8 (M = Rh and Ir) single crystals are investigated. Experiments of temperature dependent magnetic susceptibility, heat capacity and electrical resistivity measurements revealed that Cd-doping enhances the antiferromagnetic (AFM) ordering temperature from TN = 2.8 K (x = 0) to TN = 4.8 K (x = 0.21) for Ce2RhIn8-xCdx and induces long range AFM ordering with TN = 3.8 K (x = 0.21) for Ce2IrIn8-xCdx. Additionally, X-ray and neutron magnetic scattering studies showed that Cd-doped samples present below TN a commensurate antiferromagnetic structure with a propagation vector (1/2,1/2,0). The resolved magnetic structures for both compounds indicate that the Cd-doping tends to rotate the direction of the ordered magnetic moments toward the ab-plane. This result suggests that the Cd-doping affects the Ce3+ ground state single ion anisotropy modifying the crystalline electrical field (CEF) parameters at the Ce3+ site. Indications of CEF evolution induced by Cd-doping were also found in the electrical resistivity measurements. Comparisons between our results and the general effects of Cd-doping on the related compounds CeMIn5 (M = Co, Rh and Ir) confirms the claims that the Cd-doping induced electronic tuning is the main effect favoring AFM ordering in these compounds.
Expression of Interest: The Atmospheric Neutrino Neutron Interaction Experiment (ANNIE)
I. Anghel,J. F. Beacom,M. Bergevin,G. Davies,F. Di Lodovico,A. Elagin,H. Frisch,R. Hill,G. Jocher,T. Katori,J. Learned,R. Northrop,C. Pilcher,E. Ramberg,M. C. Sanchez,M. Smy,H. Sobel,R. Svoboda,S. Usman,M. Vagins,G. Varner,R. Wagner,M. Wetstein,L. Winslow,M. Yeh
Physics , 2014,
Abstract: Neutron tagging in Gadolinium-doped water may play a significant role in reducing backgrounds from atmospheric neutrinos in next generation proton-decay searches using megaton-scale Water Cherenkov detectors. Similar techniques might also be useful in the detection of supernova neutrinos. Accurate determination of neutron tagging efficiencies will require a detailed understanding of the number of neutrons produced by neutrino interactions in water as a function of momentum transferred. We propose the Atmospheric Neutrino Neutron Interaction Experiment (ANNIE), designed to measure the neutron yield of atmospheric neutrino interactions in gadolinium-doped water. An innovative aspect of the ANNIE design is the use of precision timing to localize interaction vertices in the small fiducial volume of the detector. We propose to achieve this by using early production of LAPPDs (Large Area Picosecond Photodetectors). This experiment will be a first application of these devices demonstrating their feasibility for Water Cherenkov neutrino detectors.
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.
Letter of Intent: The Accelerator Neutrino Neutron Interaction Experiment (ANNIE)
I. Anghel,J. F. Beacom,M. Bergevin,C. Blanco,E. Catano-Mur,F. Di Lodovico,A. Elagin,H. Frisch,J. Griskevich,R. Hill,G. Jocher,T. Katori,F. Krennrich,J. Learned,M. Malek,R. Northrop,C. Pilcher,E. Ramberg,J. Repond,R. Sacco,M. C. Sanchez,M. Smy,H. Sobel,R. Svoboda,S. M. Usman,M. Vagins,G. Varner,R. Wagner,A. Weinstein,M. Wetstein,L. Winslow,L. Xia,M. Yeh
Physics , 2015,
Abstract: Neutron tagging in Gadolinium-doped water may play a significant role in reducing backgrounds from atmospheric neutrinos in next generation proton-decay searches using megaton-scale Water Cherenkov detectors. Similar techniques might also be useful in the detection of supernova neutrinos. Accurate determination of neutron tagging efficiencies will require a detailed understanding of the number of neutrons produced by neutrino interactions in water as a function of momentum transferred. We propose the Atmospheric Neutrino Neutron Interaction Experiment (ANNIE), designed to measure the neutron yield of atmospheric neutrino interactions in gadolinium-doped water. An innovative aspect of the ANNIE design is the use of precision timing to localize interaction vertices in the small fiducial volume of the detector. We propose to achieve this by using early production of LAPPDs (Large Area Picosecond Photodetectors). This experiment will be a first application of these devices demonstrating their feasibility for Water Cherenkov neutrino detectors.
Observation of local chiral-symmetry breaking in globally centrosymmetric crystals
S. Di Matteo,Y. Joly,A. Bombardi,L. Paolasini,F. de Bergevin,C. R. Natoli
Physics , 2003,
Abstract: A thorough tensor analysis of the Bragg-forbidden reflection (00.3)$_h$ in corundum systems having a global center of inversion, like V$_2$O$_3$ and $\alpha$-Fe$_2$O$_3$, shows that anomalous x-ray resonant diffraction can access chiral properties related to the dipole-quadrupole (E1-E2) channel via an interference with the pure quadrupole-quadrupole (E2-E2) process. This is also confirmed by independent {\it ab initio} numerical simulations. In such a way it becomes possible, in this particular case, to estimate the intensity of the ``twisted'' trigonal crystal field ($C_3$ symmetry) and, in general, to detect chiral quantities in systems where dichroic absorption techniques are ineffective.
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