Search results for "Electromagnetic shielding"
showing 10 items of 79 documents
Neutronic and photonic analysis of the single box water-cooled lithium lead blanket for a DEMO reactor
1998
Abstract The water-cooled Pb–17Li demonstration plant (DEMO) breeding blanket line was selected in 1995 as one of the two EU lines to be further developed in the next decade. In this paper the results of a neutronic and photonic analysis of the `single box' concept is presented. A full three-dimensional model, including the whole assembly and many of the DEMO reactor components, has been developed, together with a three-dimensional neutron source. A tritium breeding ratio (TBR) value of 1.16, with no ports and a Li6 enrichment of 90%, has been obtained and a further analysis has been performed to determine Li6 enrichment that would still ensure tritium breeding self-sufficiency. Selected po…
Design approach for high efficiency NFC systems with magnetic shielding materials
2020
The performance of a Near Field Communication (NFC) antenna may be diminished when it is placed close to any conductive surface such as a metallic case or a battery. This degradation is caused due to the stray magnetic field created by the eddy currents induced on the surface, which is opposite to the intended field generated by the NFC antenna. One of the first solutions that come to mind to designers when facing this problem is the use of high permeability magnetic shielding based on sintered ferrite sheets. This is a good approach but something that is not generally taken into account is that these materials introduce an additional inductance to the NFC antenna. If the permeability of th…
EMI shielding effects of carbon nanotube cellulose nanocomposite
2010
Electromagnetic interference shielding is an important aspect of modern communication and computer technology. Carbon nanotube cellulose nanocomposite (CNTCNC) provides a novel material as an alternative to traditional metal-based shields for EMI shielding. Stratified structures containing CNTCNC layers combined with existing commercial lossy materials (like ferrite sheets) form effective EMI shields without lowering the signal integrity performance. Significant improvement in shielding effectiveness in stacked CNTCNC layers is noteworthy. CNTCNC is essentially like paper when it comes to flexibility and hence it can be easily conformed to the mechanical structure of the device in need of s…
The Shielding Effect of Drilling Fluids on MWD Downhole Compasses: The Effect of Drilling Fluid Composition, Contaminants and Rheology
2014
Materials such as added clays, weight materials, drill solids and metalic wear products in the drilling fluid are known to distort the geomagnetic field at the location of the Measurement While Drilling (MWD) tool magnetometers that are used to measure the direction of well path. This distortion contributes to substantial errors in determination of azimuth while drilling deviated wells. These errors may result in missing the target of a long deviated 12 ¼″ section in the range of 1–200m; representing a significant cost to be mitigated. The error becomes even more pronounced if drilling occurs in arctic regions close to the magnetic North Pole (or South Pole). The effect on the magnetometer …
The Shielding Effect of Drilling Fluids on Measurement While Drilling Tool Downhole Compasses—The Effect of Drilling Fluid Composition, Contaminants,…
2016
Materials such as added clays, weight materials, drill solids, and metallic wear products in the drilling fluid are known to distort the geomagnetic field at the location of the measurement while drilling (MWD) tool magnetometers that are used to measure the direction of well path. This distortion contributes to substantial errors in determination of azimuth while drilling deviated wells. These errors may result in missing the target of a long deviated 12 ¼ in. section in the range of 1–200 m, representing a significant cost to be mitigated. The error becomes even more pronounced if drilling occurs in arctic regions close to the magnetic north pole (or south pole). The effect on the magneto…
Comparison of impact characteristics of four different ice hockey arena dasher boards
2012
During recent years the incidence of ice hockey related concussions has increased. Therefore, the main aim of this study was to determine how dasher board materials and structures affect impact characteristics and thereby concussion risk. The measurements were divided into two parts; 1. physiological characteristics of body checks were determined in real game measurements, and 2. simulation of body checks in the laboratory. Peak forces and stopping distances were determined from the high-speed camera data, and stiffness values were subsequently calculated. Dasher board materials and structures had a clear effect on impact characteristics. Flexible protective shielding material resulted in 1…
SU-E-T-691: Shielding Evaluation of a Treatment Room with An Electronic Brachytherapy System
2015
Purpose: Esteya™ (Elekta) is a brachytherapy electronic system used for treating skin cancer lesions. This unit is based on a 69.5 kV X-ray source and a surface applicator which produces a circular beam of a specific diameter, which varies from 1 to 3 cm. This study aims to establish the radiation protection measures for the system. Methods: A characterization of the scattered and leakage radiation of the system was implemented by means of experimental measurements. The scattered radiation measurements were performed with a Berthold LB133 ionization chamber, evaluating the dose rate for different distances from the applicator surface. The patient was simulated through water equivalent solid…
Diatropicity of tetraazanaphthalenes
2006
Tetraazanaphthalenes are diatropic molecules, whose magnetic response to a magnetic field perpendicular to the molecular plane closely resembles that of naphthalene. The out-of-plane component of the magnetic susceptibility tensor and its strong anisotropy can be used as quantifiers of magnetic aromaticity. Maps showing streamlines and modulus of the current density field provide clear evidence for diatropicity of these systems. They also explain the strong anisotropy of carbon and nitrogen magnetic shielding, which is determined by the big out-of-plane component of the nuclear shielding tensor. The electronic ring currents observed in the map deshield the nuclei of ring hydrogens by enforc…
High-Energy Electron-Induced SEUs and Jovian Environment Impact
2017
We present experimental evidence of electron-induced upsets in a reference European Space Agency (ESA) single event upset (SEU) monitor, induced by a 200-MeV electron beam at the Very energetic Electronic facility for Space Planetary Exploration in harsh Radiation environments facility at CERN. Comparison of experimental cross sections and simulated cross sections is shown and the differences are analyzed. Possible secondary contributions to the upset rate by neutrons, flash effects, and cumulative dose effects are discussed, showing that electronuclear reactions are the expected SEU mechanism. The ESA Jupiter Icy Moons Explorer mission, to be launched in 2022, presents a challenging radiat…
Detector-electrode for alpha spectrometry in water sample, numerical and early feasibility investigation toward thermocompression bonding assembly pr…
2020
International audience; This study focuses on the feasibility of a detector-electrode for direct alpha measurement in aqueous samples. Such a device could be made by adding a boron doped diamond electrode on top of a standard silicon detector, with bonding and insulating layers. The impact of these different layers has been investigated by Monte-Carlo simulation (MCNP6), to find a compromise between alpha detection of the silicon, electrode and shielding properties of the diamond. The assembly process involving thermocompression between both substrates was successfully achieved under a clean room conditions.