Pulsed UCN production using a Doppler shifter at J-PARC

We have constructed a Doppler-shifter-type pulsed ultra-cold neutron (UCN) source at the Materials and Life Science Experiment Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). Very-cold neutrons (VCNs) with 136-$\mathrm{m/s}$ velocity in a neutron beam supplied by a pulsed neutron source are decelerated by reflection on a m=10 wide-band multilayer mirror, yielding pulsed UCN. The mirror is fixed to the tip of a 2,000-rpm rotating arm moving with 68-$\mathrm{m/s}$ velocity in the same direction as the VCN. The repetition frequency of the pulsed UCN is $8.33~\mathrm{Hz}$ and the time width of the pulse at production is $4.4~\mathrm{ms}$. In order to increase the UCN flux, a supermirror guide, wide-band monochromatic mirrors, focus guides, and a UCN extraction guide have been newly installed or improved. The $1~\mathrm{MW}$-equivalent count rate of the output neutrons with longitudinal wavelengths longer than $58~\mathrm{nm}$ is $1.6 \times 10^{2}~\mathrm{cps}$, while that of the true UCNs is $80~\mathrm{cps}$. The spatial density at production is $1.4~\mathrm{UCN/cm^{3}}$. This new UCN source enables us to research and develop apparatuses necessary for the investigation of the neutron electric dipole moment (nEDM).Comment: 32 pages, 15 fugures. A grammatical error was fixe

Power Switching in Hybrid Coherent Couplers

We report on a theoretical and numerical investigation of the switching of power in new hybrid models of nonlinear coherent couplers consisting of optical slab waveguides with various orders of nonlinearity. The first model consists of two guides with second-order instead of the usual third-order susceptibilities as typified by the Jensen coupler. This second-order system is shown to have a power self-trapping transition at a critical power greater than the third-order susceptibility coupler. Next, we consider a mixed coupler composed of a second-order guide coupled to a third-order guide and show that, although it does not display a rigorous self-trapping transition, for a particular choice of parameters it does show a fairly abrupt trapping of power at a lower power than in the third-order coupler. By coupling this mixed nonlinear pair to a third, purely linear guide, the power trapping can be brought to even lower levels and in this way a satisfactory switching profile can be achieved at less than one sixth the input power needed in the Jensen coupler.Comment: Latex source,17 pages, 5 figure

Ion-implanted lanthanum fluoride waveguides

The effects of He+ and H+ implantation into LaF3 substrates have been investigated at both room temperature and 77 K. At room temperature the surface of the samples becomes black, possibly due to chemical reduction effects, but at low temperature the crystals remain clear and a refractive index change is observed which produces a surface waveguide. The dark mode spectra of these guides have been recorded using the prism coupling technique, and their refractive index profiles have been deduced from the spacing of these modes. The ion implantation produces a thin optical barrier layer of low refractive index at the end of the ion range. This paper discusses the use of multiple-energy implantation to produce a broad optical barrier in order to reduce the tunnelling losses of the guides, and subsequent thermal annealing to reduce absorption and scattering losses caused by colour centre formation in the electronic stopping surface region of the guides. It is concluded that either single- or multiple-energy He+ implants can be ideally used to form waveguides, for applications in the blue/UV or red/IR wavelength regions, respectively, with losses of a few dB/cm

New Experiments in Minority Voter Mobilization: A Report on the California Votes Initiative

Evaluates the effectiveness of efforts in California to mobilize voters in communities with significant low-income and minority populations

Examining the trip experience on competitive advantage creation in tourism

Researchers thanked for the support by Directorate of Research and Community Service. Directorate General of Strengthening Research and Development. Ministry of Research, Technology, and Higher Education of Indonesia for the funding in year 2019.Purpose: This study aims to examine the trip experience on competitive advantage creation in Indonesia tourism. Trip experience includes transportation, accommodation, tour guide, and tourism activities. Design/Methodology/Approach: The research population consists of all international tourists who visited Indonesia through Soekarno Hatta International Airport (Jakarta) and Ngurah Rai International Airport (Bali). The questionnaire was constructed in English and translated into Arabic and Mandarin. Convenience sampling techniques were used to collect data. Out of 500 questionnaires distributed, only 415 were valid and used for analysis. Partial Least Square by SMART-PLS 3.0 software was used for data analysis. Findings: Result shows that transportation, accommodation and tourist activities are positively significant factors on tourist loyalty and mediated by tourist satisfaction. Whereas, tour guides have positively but not significant influence on tourist loyalty and mediated by tourist satisfaction. Practical implications: The study provides a practical implication which requires a close relationship of state governments and tourism companies in order to have good cooperative and coordination to competitive advantage creation. Originality/Value: As this study is based on recent studies on tourism destination in competitive advantage creation it brings a new insight of analyzing the two cities of highest tourists visits in order to understand the condition of overall Indonesian tourism.peer-reviewe

Silicon Waveguides and Ring Resonators at 5.5 {\mu}m

We demonstrate low loss ridge waveguides and the first ring resonators for the mid-infrared, for wavelengths ranging from 5.4 to 5.6 {\mu}m. Structures were fabricated using electron-beam lithography on the silicon-on-sapphire material system. Waveguide losses of 4.0 +/- 0.7 dB/cm are achieved, as well as Q-values of 3.0 k.Comment: 4 pages, 4 figures, includes supplemental material

Surface scaling behavior of isotropic Heisenberg systems: Critical exponents, structure factor, and profiles

The surface scaling behavior of classical isotropic Heisenberg magnets is investigated by Monte - Carlo methods in d=3 dimensions for various values of the surface - to - bulk coupling ratio J_1/J. For J_1/J <= 1.0 critical behavior according to the ordinary surface universality class is found. New estimates for magnetic surface exponents are presented and compared to older estimates and their theoretical counterparts. For J_1/J >= 2.0 scaling is still valid with effective exponents which depend on J_1/J. The surface structure factor S_1(p,L) is investigated at bulk criticality as function of the momentum transfer p parallel to the surface and the system size L. For J_1/J <= 1.0 and J_1/J >= 2.0 the full p dependence of S_1(p,L) can be captured by generalized shape functions to a remarkable accuracy. Profiles of the magnetization and the energy density also confirm scaling, where for J_1/J <= 1.0 the ordinary surface universality class is recovered and for J_1/J >= 2.0 scaling with J_1/J dependent exponents is found. For J_1/J = 1.5 the system displays a striking crossover behavior from spurious long - range surface order to the ordinary surface universality class. For J_1/J >= 2.0 the effective scaling laws must be interpreted as nonasymptotic and the value J_1/J = 1.5 marks a crossover regime, in which the crossover from the nonasymptotic to the asymptotic (ordinary) surface scaling behavior can be resolved within numerically attainable system sizes.Comment: 14 pages RevTeX, 14 figures; to appear in Phys. Rev. B, Sept. 200

Generic guide concepts for the European Spallation Source

The construction of the European Spallation Source (ESS) faces many challenges from the neutron beam transport point of view: The spallation source is specified as being driven by a 5 MW beam of protons, each with 2 GeV energy, and yet the requirements in instrument background suppression relative to measured signal vary between 10$^{-6}$ and 10$^{-8}$. The energetic particles, particularly above 20 MeV, which are expected to be produced in abundance in the target, have to be filtered in order to make the beamlines safe, operational and provide good quality measurements with low background. We present generic neutron guides of short and medium length instruments which are optimized for good performance at minimal cost. Direct line of sight to the source is avoided twice, with either the first point out of line of sight or both being inside the bunker (20\,m) to minimize shielding costs. These guide geometries are regarded as a baseline to define standards for instruments to be constructed at ESS. They are used to find commonalities and develop principles and solutions for common problems. Lastly, we report the impact of employing the over-illumination concept to mitigate losses from random misalignment passively, and that over-illumination should be used sparingly in key locations to be effective. For more widespread alignment issues, a more direct, active approach is likely to be needed

H-T phase diagram and the nature of Vortex-glass phase in a quasi two-dimensional superconductor: Sn metal layer sandwiched between graphene sheets

The magnetic properties of a quasi two-dimensional superconductor, Sn-metal graphite (MG), are studied using DC and AC magnetic susceptibility. Sn-MG has a unique layered structure where Sn metal layer is sandwiched between adjacent graphene sheets. This compound undergoes a superconducting transition at $T_{c}$ = 3.75 K at $H$ = 0. The $H$-$T$ diagram of Sn-MG is similar to that of a quasi two-dimensional superconductors. The phase boundaries of vortex liquid, vortex glass, and vortex lattice phase merge into a multicritical point located at $T^{*}$ = 3.4 K and $H^{*}$ = 40 Oe. There are two irreversibility lines denoted by $H_{gl}$ (de Almeida-Thouless type) and $H_{gl^{\prime}}$ (Gabay-Toulouse type), intersecting at $T_{0}^{\prime}$= 2.5 K and $H_{0}^{\prime}$ = 160 Oe. The nature of slow dynamic and nonlinearity of the vortex glass phase is studied.Comment: 24 pages, 13 figures; Physica C (2003), in pres