Picosecond timing of Microwave Cherenkov Impulses from High-Energy Particle Showers Using Dielectric-loaded Waveguides

We report on the first measurements of coherent microwave impulses from high-energy particle-induced electromagnetic showers generated via the Askaryan effect in a dielectric-loaded waveguide. Bunches of 12.16 GeV electrons with total bunch energy of $\sim 10^3-10^4$ GeV were pre-showered in tungsten, and then measured with WR-51 rectangular (12.6 mm by 6.3 mm) waveguide elements loaded with solid alumina ($Al_2 O_3$) bars. In the 5-8 GHz $TE_{10}$ single-mode band determined by the presence of the dielectric in the waveguide, we observed band-limited microwave impulses with amplitude proportional to bunch energy. Signals in different waveguide elements measuring the same shower were used to estimate relative time differences with 2.3 picosecond precision. These measurements establish a basis for using arrays of alumina-loaded waveguide elements, with exceptional radiation hardness, as very high precision timing planes for high-energy physics detectors.Comment: 16 pages, 15 figure

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

Micro ring resonators in silicon-on-insulator

Silicon as a platform for photonics has recently seen a very large increase in interest because of its potential to overcome the bandwidth limitations of microprocessor interconnects and the low manufacturing cost given by the high compatibility with the already established micro-electronics industry. There has therefore been a signicant push in silicon photonics research to develop all silicon based optical components for telecoms applications. The work reported in this Thesis is con- cerned with the design, fabrication and characterisation of coupled ring resonators on silicon-on-insulator (SOI) material. The nal objective of this work is to pro- vide a robust and reliable technology for the demonstration of optical buers and delay-lines operating at signal bandwidths up to 100 GHz and in the wavelength region around 1550 nm. The core of the activity focused on the optimisation of the fabrication technology and device geometry to ensure the required device performance for the fabrication of long chains of ring resonators. The nal pro- cess has been optimised to obtain both intra-chip and chip-to-chip reproducibility with a variability of the process controlled at the nanometre scale. This was made possible by careful control of all the variables involved in the fabrication process, reduction of the fabrication complexity, close feature-size repeatability, line-edge roughness reduction, nearly vertical sidewall proles and high uniformity in the ebeam patterning. The best optical propagation losses of the realized waveguides reduced down to 1 dB=cm for 480 220 nm2 rectangular cross-section photonic wires and were consistently kept at typical values of around 1.5 dB=cm. Control of the coupling coecients between resonators had a standard deviation of less than 4 % for dierent realizations and resonance dispersion between resonators was below 50 GHz. All these gures represent the state-of-the-art in SOI photon- ics technology. Considerable eort has also been devoted to the development of ecient thermal electrodes (52 W=GHz) to obtain a recongurable behaviour of the structure and polymer inverse tapers to improve the o-chip coupling (inser- tion losses < 2 dB). Phase-preserving and error-free transmission up to 100 Gbit=s with continuously tunable optical delay up to 200 ps has been demonstrated on the nal integrated systems, proving the compatibility of these devices with advanced modulation formats and high bit-rate transmission systems

From FPGA to ASIC: A RISC-V processor experience

This work document a correct design flow using these tools in the Lagarto RISC- V Processor and the RTL design considerations that must be taken into account, to move from a design for FPGA to design for ASIC

An Implantable Low Pressure Biosensor Transponder

The human body’s intracranial pressure (ICP) is a critical element in sustaining healthy blood flow to the brain while allowing adequate volume for brain tissue within the relatively rigid structure of the cranium. Disruptions in the body’s maintenance of intracranial pressure are often caused by hemorrhage, tumors, edema, or excess cerebral spinal fluid resulting in treatments that are estimated to globally cost up to approximately five billion dollars annually. A critical element in the contemporary management of acute head injury, intracranial hemorrhage, stroke, or other conditions resulting in intracranial hypertension, is the real-time monitoring of ICP. Currently such monitoring can only take place short-term within an acute care hospital, is prone to measurement drift, and is comprised of externally tethered pressure sensors that are temporarily implanted into the brain, thus carrying a significant risk of infection. To date, reliable, low drift, completely internalized, long-term ICP monitoring devices remain elusive. In addition to being safer and more reliable in the short-term, such a device would expand the use of ICP monitoring for the management of chronic diseases involving ICP hypertension and further expand research into these disorders. This research studies the current challenges of existing ICP monitoring systems and investigates opportunities for potentially allowing long-term implantable bio-pressure sensing, facilitating possible improvements in treatment strategies. Based upon the research, this thesis evaluates piezo-resistive strain sensing for low power, sub-millimeter of mercury resolution, in application to implantable intracranial pressure sensing