Belle II iTOP Optics: Design, Construction and Performance

The imaging-Time-of-Propogation (iTOP) counter is a new type of ring-imaging Cherenkov counter developed for particle identification at the Belle II experiment. It consists of 16 modules arranged azimuthally around the beam line. Each module consists of one mirror, one prism and two quartz bar radiators. Here we describe the design, acceptance test, alignment, gluing and assembly of the optical components. All iTOP modules have been successfully assembled and installed in the Belle II detector by the middle of 2016. After installation, laser and cosmic ray data have been taken to test the performance of the modules. First results from these tests are presented.Comment: Proceedings of TIPP 2017, May 22 - 26, Beijing, China, 2017; University of Cincinnati preprint UCHEP-17-07. arXiv admin note: text overlap with arXiv:1709.0993

Effect of Soil Dilatancy on Vibration and Earth Pressure

A model ground of air dried sand compacted in a shear testing apparatus and two composite models each of which have the model pit of different rigidity buried in a same model ground as above one are excited horizontally with sinusoidal motions on a shaking table. From measured accelerations and dynamic earth pressure it is found that the vertical vibration is produced in the ground due to the dilatancy or volume change of soil and yet it produces the dynamic earth pressure acting horizontally on all outside walls of the model pit. In order to simulate the results of tests three dimensional finite element procedure with elasto-plastic dynamic response analysis is used. Good agreement between the tests results and predictions is obtained

Electrical transport properties of atomically thin WSe2 using perpendicular magnetic anisotropy metal contacts

Tungsten diselenide, WSe2 shows excellent properties and become very promising material among two dimensional semiconductors. Wide band gap and large spin-orbit coupling along with naturally lacking inversion symmetry in the monolayer WSe2 make it efficient material for spintronics, optoelectronics and valleytronics applications. In this work, we report electrical transport properties of monolayer WSe2 based field effect transistor with most needed multilayer Co/Pt ferromagnetic electrodes exhibiting perpendicular magnetic anisotropy. We studied contacts behaviour by performing I-V curve measurements and estimating Schottky barrier heights (SBHs). SBHs estimated from experimental data are found to be comparatively small, without using any tunnel barrier. This work expands the current understanding of WSe2 based devices and gives insight into the electrical behaviour of Co/Pt metal contacts, which can open great possibilities for spintronic/valleytronic applications.Comment: 8 pages, 4 figure