Search results for "WAF"
showing 10 items of 85 documents
Description and commissioning of NEXT-MM prototype: first results from operation in a Xenon-Trimethylamine gas mixture
2014
[EN] A technical description of NEXT-MM and its commissioning and first performance is reported. Having an active volume of ∼35 cm drift × 28 cm diameter, it constitutes the largest Micromegas-read TPC operated in Xenon ever constructed, made by a sectorial arrangement of the 4 largest single wafers manufactured with the Microbulk technique to date. It is equipped with a suitably pixelized readout and with a sufficiently large sensitive volume (∼23 l) so as to contain long (∼20 cm) electron tracks. First results obtained at 1 bar for Xenon and Trymethylamine (Xe-(2%)TMA) mixture are presented. The TPC can accurately reconstruct extended background tracks. An encouraging fu…
High efficiency frequency doubling in fully diced LiNbO3ridge waveguides on silicon
2016
Nonlinear periodically poled ridge LiNbO3 waveguides have been fabricated on silicon substrates. Components are carved with only the use of a precision dicing machine without the need for grinding or polishing steps. They show efficient second harmonic generation at telecommunication wavelengths with normalized conversion reaching 204%/W in a 15 mm long device. The influence of the geometrical non uniformities of waveguides due to fabrication processes is asserted. Characteristics of the components are studied; notably their robustness and tunability versus temperature.
HALE-IoT: HArdening LEgacy Internet-of-Things devices by retrofitting defensive firmware modifications and implants
2022
Internet-Of-Things (IoT) devices and their firmware are notorious for their lifelong vulnerabilities. As device infection increases, vendors also fail to release patches at a competitive pace. Despite security in IoT being an active area of research, prior work has mainly focused on vulnerability detection and exploitation, threat modelling, and protocol security. However, these methods are ineffective in preventing attacks against legacy and End-Of-Life devices that are already vulnerable. Current research mainly focuses on implementing and demonstrating the potential of malicious modifications. Hardening emerges as an effective solution to provide IoT devices with an additional layer of d…
Benzene monitoring by micro-machined sensors with SnO2 layer obtained by using micro-droplet deposition technique
2011
International audience; SnO2 thin layers were deposited by the way of the micro-droplet technique. The sensor substrate consisted of a thin membrane developed on oxidised silicon wafer. The sensing layers were deposited by means of the micro-droplet technique into thin layers of about 100 nm. Such devices were tested for benzene detection. The obtained results showed a very high sensitivity for this chemical compound since 500 ppb were detected. The results presented in this paper were not focused on the reactional mechanism of benzene detection but rather on the development of a cheap and sensitive sensor using sol-gel and micro-droplet processes. Since these layers were elaborated using s…
Comparing different processing methods in apple slice drying. Part 1. Performance of microwave, hot air and hybrid methods at constant temperatures
2019
The drying curves, energy efficiency and colour variations of sliced apples dried at various temperatures and using different techniques were evaluated, i.e. microwave (35, 55 and 65 °C), hot air (35, 55, 65 and 75 °C) and combination of both (65 °C). The microwave (MW) tests also included comparison between air recirculation and continuous inlet of fresh air. Each drying method was evaluated at a fixed temperature level by means of a control system based on infrared thermography. The time required to complete the drying process at 65 °C varied from about 44 min for MW with fresh air ventilation (double with air recirculation), to 122 min for hybrid heating and 238 min for hot air. Drying k…
Growth of polyaniline films on porous silicon layers
1993
Abstract The electrochemical deposition of electrically active polyaniline films (PANI) onto the surface of porous silicon (PS) layers formed at p- and n-type silicon wafers has been studied using cyclic voltammetry measurements and infrared spectroscopy. The process of PANI deposition is easier on the PS layers formed at n-Si wafers and essentially retarded at PS/p-Si samples, presumably due to a parallel reaction of oxygen evolution. The polymerization reaction starts at the pore bottoms and propagates towards the external surface of the PS layer. Electric conduction of PS/PANI composites is lower than of uncovered PS layers.
Particle Detectors made of High Resistivity Czochralski Grown Silicon
2004
We describe the fabrication process of fullsize silicon microstrip detectors processed on silicon wafers grown by magnetic Czochralski method. Defect analysis by DLTS spectroscopy as well as minority carrier lifetime measurements by µPCD method are presented. The electrical and detection properties of the Czochralski silicon detectors are comparable to those of leading commercial detector manufacturers. The radiation hardness of the Czochralski silicon detectors was proved to be superior to the devices made of traditional Float Zone silicon material.
Planar Array Technology for the Fabrication of Germanium X-Ray Microcalorimeters
2008
Several technologies are presently competing for measuring the temperature increase in cryogenic micro-calorimeters used as high resolution energy-dispersive X-ray detectors. Doped germanium, whose resistivity depends on temperature, is a promising material for this purpose, because of its comparatively low specific heat and the possibility of making wafers with high doping uniformity by neutron transmutation. Presently, Ge-based microcalorimeters are still micro-machined and manually assembled. Here we present a planar approach to the fabrication of 2-D arrays of microcalorimeters and show the preliminary technological results.
Crystallization of silica opals onto patterned silicon wafer
2006
We report on fabrication of high quality opaline photonic crystals from large silica spheres, self-assembled in hydrophilic trenches of silicon wafers by using a drawing apparatus with a combination of stirring. The achievements here reported comprise a spatial selectivity of opal crystallization without special treatment of the wafer surface, a filling of the trenches up to the top, leading to a spatially uniform film thickness, particularly an absence of cracks within the size of the trenches, and finally a good three-dimensional order of the opal lattice even in trenches with a complex confined geometry, verified using optical measurements. The opal lattice was found to match the pattern…
Flexible MgO-Based Magnetic Tunnel Junctions on Silicon Substrate
2018
Flexible electronic devices are emerging in many areas, providing novel features and creating new applications [1]. Due to their ubiquitous utilization, flexible magnetic sensors [2] play a critical part in this development. In particular, magnetic tunnel junctions (MTJs) are of great interest, because of advantages like low power consumption or high sensitivity. We report the development of flexible MTJs on a silicon substrate fabricated by a low-cost batch process [3]. Thereby, conventionally fabricated MTJ devices are transformed into flexible ones by thinning down the silicon wafer from 500 μm to 5 μm. This process leads to thin, bendable silicon devices, while maintaining their origina…