Belle II Technical Design Report

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un

Topical Workshop on Electronics for Particle Physics

The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities

Light Manipulation in Multilayer Metamaterials

Light manipulation has become much more sophisticated with the development of artificial metamaterials. Here, I have studied multilayer thin film-based hyperbolic metamaterials (HMM) in both planar and cylindrical formations. First, the planar HMMs are used as epsilon-near-zero (ENZ) substrates to control the spectral position of plasmonic resonance. The resonance shift is reduced three times on top of HMM compared to a glass substrate. Next, the thin films are rolled to form three-dimensional (3D) rolled-up tubes (RUT) using a strained induced self-rolling mechanism. The RUTs offer flexibility to use a broad range of materials for rolling by using photoresist and germanium as a sacrificial layer. The RUTs are fabricated with different diameters ranging from ∼1 µm to 10 µm by simply changing the thicknesses of dielectric and metal layers. The walls of the RUTs offer tunable material dispersion and can be used as 3D ENZ metamaterials. While, the core of these RUTs can be used as waveguides, which can support the ENZ mode. The modeling manifests that the material dispersion is a function of the thicknesses of the layers and the number of turns and ENZ mode is very sensitive to the diameter of the RUT. Finally, the upper side of the RUT is patterned to form 3D fishnet metamaterials, which exhibit a negative index of refraction in the near-infrared region with low loss and a better figure of merit. The patterning is further upgraded to form nanohole-based metasurfaces that can control the wavefront of light. The curved metasurfaces out-perform the conventional planar metasurfaces. The large diameter of RUTs provides enough area to pattern a good number of unit cells, that can be optically characterized. The results of this thesis show that the planar HMMs can be used to effectively reduce the fabrication error for advanced metasurfaces and plasmonic applications. The cylindrical HMMs can serve as a unique platform for 3D metamaterials suitable for sensing applications, trapping biological cells, neurons, and optical trapping of particles

Kinematics and Robot Design IV, KaRD2021

This volume collects the papers published on the special issue “Kinematics and Robot Design IV, KaRD2021” (https://www.mdpi.com/journal/robotics/special_issues/KaRD2021), which is the forth edition of the KaRD special-issue series, hosted by the open-access journal “MDPI Robotics”. KaRD series is an open environment where researchers can present their works and discuss all the topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. Kinematics is so intimately related to the design of robotic/automatic systems that the admitted topics of the KaRD series practically cover all the subjects normally present in well-established international conferences on “mechanisms and robotics”. KaRD2021, after the peer-review process, accepted 12 papers. The accepted papers cover some theoretical and many design/applicative aspects

Spark Breakdown Voltage Sampling During Early Stage Compression

This thesis proposes a novel methodology to enable cycle by cycle control of a two-stroke cycle type engine. These engines are well known for offering high specific power density solutions, however, this advantage cannot be fully exploited without new technologies enabling significantly reduced emissions and improved fuel economy. If this could be provided, working with direct fuel injection, new highly efficient, low emission, power units could result. One of the main reasons why this has not previously been achieved has been the inability to accurately measure and quantify the amount of combustible charge available for metering of the Air/Fuel ratio. This is due to the highly dynamic gas conditions in the engine which cause significant cyclic variations of scavenging and trapping efficiencies. Existing combustion control methods are unable to accurately compensate for these conditions because fuel quantity is determined using the results of previous combustion events which do not reflect the actual gases available for each combustion. This thesis proposes a different approach, whereby accurate fuel quantities could be determined cyclically from in-cylinder measurements ahead of each combustion event. The intention being, for optimal fuel quantities and ignition initiation timings to be calculated and provided for each cycle. This technology would significantly improve the ability to achieve an optimal combustion of each individual combustion event. The principle of measurement uses and extends proven existing extensive scientific knowledge of the relationships between the value of Spark Break-Down Voltage (SBDV) to gas density and speciation. The methodology presented, applied pulses of voltage to the spark plug, which is normally used only to initiate ignition, to also function as a non-intrusive in-cylinder sensor. Experimental results were obtained using three items of equipment purposely designed and manufactured for the present work. These consisted of a) A new high frequency spark breakdown voltage electronic circuit. b) A static volume sparking chamber. c). A motored test engine into which exhaust gas was supplied from an auxiliary engine via an air mixing system. The novel use of an auxiliary engine enabled a wide range of mass fractions to be subjected to cyclic compression events for evaluation independent of test engine conditions

【１】研究活動

工学部通