Since entangled multiple optical fields were identified as the building blocks of quantum networks,the quadripartite entangled optical fields have been produced by using four degenerate optical parametric amplifiers o...
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Since entangled multiple optical fields were identified as the building blocks of quantum networks,the quadripartite entangled optical fields have been produced by using four degenerate optical parametric amplifiers or two nondegenerate optical parametric amplifiers(NOPAs).However,realizing an efficient and compact source for multiple quantum users has remained an outstanding challenge,hindering their practical ***,we proposed a compact and feasible scheme to deterministically entangle four spatially separated optical fields,employing only a single ***,two-sided output NOPA-based optical fields were coupled on a beam splitter network to form the quadripartite entangled state,causing the deterministic generation of both the Greenberger–Horne–Zeilinger(GHZ)and the linear cluster states in this compact entanglement *** also obtained the optimal experimental parameters based on the simulation results,thereby providing a direct reference for experimental *** findings propose that the resultant GHZ and linear cluster states can be potentially applied in quantum-enhanced information science,specifically in quantum secret sharing,controlled quantum teleportation networks,and quantum-entangled atomic ensemble networks.
We report on a grating Bonse-Hart interferometer for phase-contrast imaging with hard X-rays. The method overcomes limitations in the level of sensitivity that can be achieved with the well-known Talbot grating interf...
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We report on a grating Bonse-Hart interferometer for phase-contrast imaging with hard X-rays. The method overcomes limitations in the level of sensitivity that can be achieved with the well-known Talbot grating interferometer, and without the stringent spectral filtering at any given incident angle imposed by the classic Bonse-Hart interferometer. The device operates in the far-field regime, where an incident beam is split by a diffraction grating into two widely separated beams, which are redirected by a second diffraction grating to merge at a third grating, where they coherently interfere. The wide separation of the interfering beams results in large phase contrast, and in some cases absolute phase images are obtained. Imaging experiments were performed using diffraction gratings of 200 nm period, at 22.5 keV and 1.5% spectral bandwidth on a bending-magnetic beamline. Novel design and fabrication process were used to achieve the small grating period. Using a slitted incident beam, we acquired absolute and differential phase images of lightly absorbing samples. An advantage of this method is that it uses only phase modulating gratings, which are easier to fabricate than absorption gratings of the same periods.
This article briefly describes the basic design of the ESS-Bilbao neutron target station as well as its expected neutronic performance. The baseline engineering design, associated ancillary systems, and plant layout f...
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This article briefly describes the basic design of the ESS-Bilbao neutron target station as well as its expected neutronic performance. The baseline engineering design, associated ancillary systems, and plant layout for the facility is now complete. A rotating target composed of twenty beryllium plates has been selected as the best choice in terms of both neutron yield and engineering complexity. It will provide neutron beams with a source term of 10 15 n s −1 resulting from the direct 9 Be ( p, xn ) reaction using a 75 mA proton beam at 50 MeV. The design envisages a target station equipped with two fully optimized moderators capable of withstanding a proton-beam power of 112 kW. This design is flexible enough to accommodate future upgrades in final proton energy. The envisaged neutron-beam brightness will enable several applications, including the use of cold and thermal neutrons for condensed matter research as well as fast-neutron irradiation studies. We close by discussing the role that this facility may play once the European Spallation source becomes operational in Lund, Sweden.
The European Spallation source-Bilbao (ESS-Bilbao) project plans to build an accelerator facility compliant with the ESS-AB requirements which will be able to drive several experimental stations for research purposes ...
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The European Spallation source-Bilbao (ESS-Bilbao) project plans to build an accelerator facility compliant with the ESS-AB requirements which will be able to drive several experimental stations for research purposes involving intense proton beams with currents up to 75 mA, 50 MeV of final energy, 1.5 ms of pulse length and up to 50 Hz repetition rate. The accelerator will also drive a compact neutron source which will provide useful neutron beams to carry out experiments on moderator optimization, neutron optics devices and general neutron instrumentation as well as preparation work for experiments to be carried out by neutron beam users at the large facilities. (C) 2012 Elsevier B.V. All rights reserved.
The ESS-Bilbao facility, hosted by the University of the Basque Country (UPV/EHU), envisages the operation of a high-current proton accelerator delivering beams with energies up to 50 MeV. The time-averaged proton cur...
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The ESS-Bilbao facility, hosted by the University of the Basque Country (UPV/EHU), envisages the operation of a high-current proton accelerator delivering beams with energies up to 50 MeV. The time-averaged proton current will be 2.25 mA, delivered by 1.5 ms proton pulses with a repetition rate of 20 Hz. This beam will feed a neutron source based upon the Be (p,n) reaction, which will enable the provision of relevant neutron experimentation capabilities. The neutron source baseline concept consists in a rotating beryllium target cooled by water. The target structure will comprise a rotatable disk made of 6061-T6 aluminium alloy holding 20 beryllium plates. Heat dissipation from the target relies upon a distribution of coolant-flow channels. The practical implementation of such a concept is here described with emphasis put on the beryllium plates thermo-mechanical optimization, the chosen coolant distribution system as well as the mechanical behavior of the assembly. (C) 2013 Elsevier B.V. All rights reserved.
This paper presents the results of measurements of the Crab nebula in the decametre range with an interferometer whose baseline is 2.4–3.5×103 of the wavelength. Visibility function values, which in these observ...
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This paper presents the results of measurements of the Crab nebula in the decametre range with an interferometer whose baseline is 2.4–3.5×103 of the wavelength. Visibility function values, which in these observations determine the contribution by the compact source to the total nebula flux, have been measured at frequencies 16.7, 20 and 25 MHz to be 0.64±0.07, 0.43±0.04 and 0.31±0.03, respectively. The spectral index of the spectrum obtained for the compact source in the range 16.7–122 MHz is 2.09±0.04. Flattening of the nebula spectrum without the compact source has been confirmed for the decametre range.
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