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Sample records for electronic stopping power

  1. Stopping Power for Degenerate Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-16

    This is a first attempt at calculating the BPS stopping power with electron degeneracy corrections. Section I establishes some notation and basic facts. Section II outlines the basics of the calculation, and in Section III contains some brief notes on how to proceed with the details of the calculation. The remaining work for the calculation starts with Section III.

  2. Electron and Positron Stopping Powers of Materials

    Science.gov (United States)

    SRD 7 NIST Electron and Positron Stopping Powers of Materials (PC database for purchase)   The EPSTAR database provides rapid calculations of stopping powers (collisional, radiative, and total), CSDA ranges, radiation yields and density effect corrections for incident electrons or positrons with kinetic energies from 1 keV to 10 GeV, and for any chemically defined target material.

  3. Electron mass stopping power in H2

    Science.gov (United States)

    Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor

    2017-08-01

    Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].

  4. Electron stopping powers for transport calculations

    International Nuclear Information System (INIS)

    Berger, M.J.

    1988-01-01

    The reliability of radiation transport calculations depends on the accuracy of the input cross sections. Therefore, it is essential to review and update the cross sections from time to time. Even though the main interest of the author's group at NBS is in transport calculations and their applications, the group spends almost as much time on the analysis and preparation of cross sections as on the development of transport codes. Stopping powers, photon attenuation coefficients, bremsstrahlung cross sections, and elastic-scattering cross sections in recent years have claimed attention. This chapter deals with electron stopping powers (with emphasis on collision stopping powers), and reviews the state of the art as reflected by Report 37 of the International Commission on Radiation Units and Measurements

  5. Ab initio electronic stopping power in materials

    International Nuclear Information System (INIS)

    Shukri, Abdullah-Atef

    2015-01-01

    The average energy loss of an ion per unit path length when it is moving through the matter is named the stopping power. The knowledge of the stopping power is essential for a variety of contemporary applications which depend on the transport of ions in matter, especially ion beam analysis techniques and ion implantation. Most noticeably, the use of proton or heavier ion beams in radiotherapy requires the knowledge of the stopping power. Whereas experimental data are readily available for elemental solids, the data are much more scarce for compounds. The linear response dielectric formalism has been widely used in the past to study the electronic stopping power. In particular, the famous pioneering calculations due to Lindhard evaluate the electronic stopping power of a free electron gas. In this thesis, we develop a fully ab initio scheme based on linear response time-dependent density functional theory to predict the impact parameter averaged quantity named the random electronic stopping power (RESP) of materials without any empirical fitting. The purpose is to be capable of predicting the outcome of experiments without any knowledge of target material besides its crystallographic structure. Our developments have been done within the open source ab initio code named ABINIT, where two approximations are now available: the Random-Phase Approximation (RPA) and the Adiabatic Local Density Approximation (ALDA). Furthermore, a new method named 'extrapolation scheme' have been introduced to overcome the stringent convergence issues we have encountered. These convergence issues have prevented the previous studies in literature from offering a direct comparison to experiment. First of all, we demonstrate the importance of describing the realistic ab initio electronic structure by comparing with the historical Lindhard stopping power evaluation. Whereas the Lindhard stopping power provides a first order description that captures the general features of the

  6. STARCODES, Stopping Power and Ranges for Electrons, Protons, He

    International Nuclear Information System (INIS)

    2000-01-01

    1 - Description of program or function: The 'STAR CODES', ESTAR, PSTAR, and ASTAR, calculate stopping-power and range tables for electrons, protons, and helium ions (alphas), according to methods described in ICRU Reports 37 and 39. 2 - Method of solution: Collision stopping powers are calculated from the theory of Bethe (1930, 1932), with a density-effect correction evaluated according to Sternheimer (1952, 1982). The stopping-power formula contains an important parameter, the mean excitation energy (I-value), which characterizes the stopping properties of a material. The codes provide output for electrons in any stopping material (279 provided) and for protons and helium ions in 74 materials. The calculations include the 1) Collision stopping power, 2) Radiative stopping power (electrons only), 3) Nuclear stopping power (protons and helium ions), 4) Total stopping power, 5) CSDA range, 6) Projected range (protons and helium ions), 7) Density effect parameter (electrons), 8) Radiation yield (electrons), and 9) Detour factor (protons and helium ions). Standard energy grids and files of elements w/ionization-excitation information are included with lookup table capabilities. 3 - Restrictions on the complexity of the problem: The minimum energies used in the calculations are at 1 KeV (protons and helium ions) and 10 KeV (electrons), and the maximum are 1 GeV. The standard energy grids are set at 81 for electrons, equally spaced (logarithmically), 133 for protons, and 122 for helium ions. The lower energy electron calculations (< 10 KeV) have up to 5-10% errors and are considered too fallable

  7. Stopping power of K electrons at extreme relativistic energies

    International Nuclear Information System (INIS)

    Leung, P.T.; Rustgi, M.L.

    1983-01-01

    The recent work of Anholt on K-vacancy production by relativistic projectiles has been applied to calculate the stopping power of the K electrons. The results show that for protons of energy approx.10 3 GeV and heavy target elements, the relativistic contributions to the stopping power amount to several times the resuls due to the longitudinal terms obtained from Walske's work

  8. Stopping power of degenerate electron liquid at metallic densities

    International Nuclear Information System (INIS)

    Tanaka, Shigenori; Ichimaru, Setsuo

    1985-01-01

    We calculate the stopping power of the degenerate electron liquid at metallic densities in the dielectric formalism. The strong Coulomb-coupling effects beyond the random-phase approximation are taken into account through the static and dynamic local-field corrections. It is shown that those strong-coupling and dynamic effects act to enhance the stopping power substantially in the low-velocity regime, leading to an improved agreement with experimental data. (author)

  9. Electronic Stopping Power in LiF from First Principles

    International Nuclear Information System (INIS)

    Pruneda, J. M.; Sanchez-Portal, D.; Arnau, A.; Juaristi, J. I.; Artacho, Emilio

    2007-01-01

    Using time-dependent density-functional theory we calculate from first principles the rate of energy transfer from a moving proton or antiproton to the electrons of an insulating material, LiF. The behavior of the electronic stopping power versus projectile velocity displays an effective threshold velocity of ∼0.2 a.u. for the proton, consistent with recent experimental observations, and also for the antiproton. The calculated proton/antiproton stopping-power ratio is ∼2.4 at velocities slightly above the threshold (v∼0.4 a.u.), as compared to the experimental value of 2.1. The projectile energy loss mechanism is observed to be extremely local

  10. Electron stopping power in dosimetry. I. Evolution and present status

    International Nuclear Information System (INIS)

    Andreo, P.

    1985-01-01

    A review of the theory and the evolution of the calculation of the collision stopping power of electrons has been performed. Special emphasis has been given to those aspects and materials used in the dosimetry electron and photon beams. The important parameters mean excitation energy and the density effect correction are considered in detail to clarify the different models and data available at the present time. Updated data, comparisons and results are given using the formulation and numerical values described in this work. (author)

  11. Contribution of inner shell electrons to position-dependent stopping powers of a crystal surface

    International Nuclear Information System (INIS)

    Narumi, Kazumasa; Fujii, Yoshikazu; Kishine, Keiji; Kurakake, Hiroshi; Kimura, Kenji; Mannami, Michi-hiko

    1994-01-01

    Position-dependent stopping powers of the (001) surface of SnTe single crystal for specularly reflected 15 - 200 keV H + ions are studied. The position dependence of the experimental stopping powers varies with the energy of ions. From the comparison with the theoretical stopping powers based on both the single ion-electron collision and the collective excitation of the valence electrons, it is concluded that the observed change in the position-dependent stopping powers with energy of H + is due to the variation of contribution of inner shell electrons to stopping. (author)

  12. The calculation of proton and secondary electron stopping powers in liquid water

    International Nuclear Information System (INIS)

    Marouane, Abdelhak; Inchaouh, Jamal; Ouaskit, Said; Fathi, Ahmed

    2012-01-01

    The stopping power of energetic protons in liquid water has been calculated using a new model based on different theoretical and semi-empirical approaches. In this model, we consider the relativistic corrections along with the electronic and nuclear stopping power. The present work accounts for the different interactions made with electrons and nuclei inside the target. Interactions of the incident particle with the target's electrons dominate in the high energy regime; in the low energy regime, the interactions of the projectile with the target nuclei contribute importantly and are included in the calculation. We also compute the stopping cross sections and the stopping power of secondary electrons ejected from proton and hydrogen ionization impact, and generated by hydrogen electron loss processes. The consideration of secondary electrons' stopping power can contribute to the study of nano-dosimetry. Our results are in good agreement with existing experimental data. This calculation model can be useful for different applications in medical physics and space radiation health, such as hadron therapy for cancer treatment or radiation protection for astronauts. - Highlights: ► We discussed the stopping cross sections at the Bragg peak region of primary and secondary processes. ► We considered the corrections of incident particle energy focusing on the Rudds semi-empirical model. ► We calculated the electronic and nuclear stopping power, and we deduced the total stopping power. ► We calculated the stopping power of the secondary electrons.

  13. Stopping powers of energetic electrons penetrating condensed matter-theory and application

    International Nuclear Information System (INIS)

    Tan Zhenyu; Xia Yueyuan

    2004-01-01

    In this review article, the motivation of studying inelastic energy loss for energetic electrons penetrating through matter and the corresponding technological importance have been outlined. The theoretical development and method for the calculation of stopping powers are described. The stopping power data tables for a group of polymers and bioorganic compounds are presented, and the application aspects of the stopping power data are briefly discussed. (authors)

  14. Consistent calculation of the stopping power for slow ions in two-dimensional electron gases

    International Nuclear Information System (INIS)

    Wang, You-Nian; Ma, Teng-Gai

    1997-01-01

    Within the framework of quantum scattering theory, we present a consistent calculation of the stopping power for slow protons and antiprotons moving in two-dimensional electron gases. The Friedel sum rule is used to determine the screening constant in the scattering potential. For the stopping power our results are compared with that of the random-phase approximation dielectric theory and that predicted by the linear Thomas-Fermi potential. copyright 1997 The American Physical Society

  15. Analytic formula of stopping power for high energy electrons in liquid media

    International Nuclear Information System (INIS)

    Scarlat, F.; Niculescu, V.I.R.

    1994-01-01

    This article is part of a series on the calculation of high energy electron dose using multiple scattering theory. In the current article we present an analytic formula obtained for the collision stopping power (S/ρ) c and the radiative stopping power (S/ρ) r for electrons with energy within 1 MeV - 35 MeV range. For that purpose we used data given for electrons in water in NBS-IR-2550A. The analytical formulae are approximating the data calculated by Berger and Seltzer within 1-2% limit. (Author)

  16. Simple polynomial approximation to modified Bethe formula low-energy electron stopping powers data

    Energy Technology Data Exchange (ETDEWEB)

    Taborda, A., E-mail: ana.taborda@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 92262 Fontenay-aux-Roses (France); Desbrée, A. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 92262 Fontenay-aux-Roses (France); Reis, M.A. [C" 2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, EN10 km139.7, 2685-066 Bobadela LRS (Portugal)

    2015-08-01

    A recently published detailed and exhaustive paper on cross-sections for ionisation induced by keV electrons clearly shows that electron phenomena occurring in parallel with X-ray processes may have been dramatically overlooked for many years, mainly when low atomic number species are involved since, in these cases, the fluorescence coefficient is smaller than the Auger yield. An immediate problem is encountered while attempting to tackle the issue. Accounting for electron phenomena requires the knowledge of the stopping power of electrons within, at least, a reasonably small error. Still, the Bethe formula for stopping powers is known to not be valid for electron energies below 30 keV, and its use leads to values far off experimental ones. Recently, a few authors have addressed this problem and both detailed tables of electron stopping powers for various atomic species and attempts to simplify the calculations, have emerged. Nevertheless, its implementation in software routines to efficiently calculate keV electron effects in materials quickly becomes a bit cumbersome. Following a procedure already used to establish efficient methods to calculate ionisation cross-sections by protons and alpha particles, it became clear that a simple polynomial approximation could be set, which allows retrieving the electronic stopping powers with errors of less than 20% for energies above 500 eV and less than 50% for energies between 50 eV and 500 eV. In this work, we present this approximation which, based on just six parameters, allows to recover electron stopping power values that are less than 20% different from recently published experimentally validated tabulated data.

  17. Electronic stopping powers for fluorine ions in 19F+-implanted silver gallium diselenide

    International Nuclear Information System (INIS)

    Liu Xiangdong; Xia Yueyuan; Li Feng; Lu Qingming; Huang Boda

    2004-01-01

    Electronic stopping powers for 80-350 keV 19 F ions in AgGaSe 2 were obtained by range measurement. Depth profiles of 19 F in AgGaSe 2 were measured by using the 19 F(p,αγ) 16 O resonant nuclear reaction at E R =872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross-sections were compared with those obtained from Monte Carlo simulation codes

  18. Electronic stopping powers for fluorine ions in {sup 19}F{sup +}-implanted silver gallium diselenide

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiangdong E-mail: xdliu@sdu.edu.cn; Xia Yueyuan; Li Feng; Lu Qingming; Huang Boda

    2004-08-01

    Electronic stopping powers for 80-350 keV {sup 19}F ions in AgGaSe{sub 2} were obtained by range measurement. Depth profiles of {sup 19}F in AgGaSe{sub 2} were measured by using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonant nuclear reaction at E{sub R}=872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross-sections were compared with those obtained from Monte Carlo simulation codes.

  19. Electronic stopping power of polymers for heavy ions in the ion energy domain of LSS theory

    Energy Technology Data Exchange (ETDEWEB)

    Neetu [Department of Physics, Kurukshetra University, Kurukshetra 136 119, Haryana (India)], E-mail: neetuphy@gmail.com; Pratibha [Department of Physics, Kurukshetra University, Kurukshetra 136 119, Haryana (India); Sharma, V. [Department of Physics, Lovely Professional University, Phagwara 144 402 (India); Diwan, P.K. [Department of Physics, U.I.E.T., Kurukshetra University, Kurukshetra 136119, Haryana (India); Kumar, Shyam [Department of Physics, Kurukshetra University, Kurukshetra 136 119, Haryana (India)

    2009-04-15

    LSS based computed electronic stopping power values have been compared with the corresponding measured values in polymers for heavy ions with Z = 5-29, in the reduced ion velocity region, v{sub red} {<=} 1. Except for limited v{sub red} {approx} 0.6-0.85, the formulation generally shows significantly large deviations with the measured values. The {zeta} factor, which was approximated to be {approx}Z{sub 1}{sup 1/6}, involved in LSS theory has been suitably modified in the light of the available experimental stopping power data. The calculated stopping power values after incorporating modified {zeta} in LSS formula have been found to be in close agreement with measured values in various polymers in the reduced ion velocity range 0.35 {<=} v{sub red} {<=} 1.0.

  20. Electronic stopping power of polymers for heavy ions in the ion energy domain of LSS theory

    International Nuclear Information System (INIS)

    Neetu; Pratibha; Sharma, V.; Diwan, P.K.; Kumar, Shyam

    2009-01-01

    LSS based computed electronic stopping power values have been compared with the corresponding measured values in polymers for heavy ions with Z = 5-29, in the reduced ion velocity region, v red ≤ 1. Except for limited v red ∼ 0.6-0.85, the formulation generally shows significantly large deviations with the measured values. The ζ factor, which was approximated to be ∼Z 1 1/6 , involved in LSS theory has been suitably modified in the light of the available experimental stopping power data. The calculated stopping power values after incorporating modified ζ in LSS formula have been found to be in close agreement with measured values in various polymers in the reduced ion velocity range 0.35 ≤ v red ≤ 1.0.

  1. Secondary electrons as probe of preequilibrium stopping power of ions penetrating solids

    International Nuclear Information System (INIS)

    Kroneberger, K.; Rothard, H.; Koschar, P.; Lorenzen, P.; Groeneveld, K.O.; Clouvas, A.; Veje, E.; Kemmler, J.

    1990-01-01

    The passage of ions through solid media is accompanied by the emission of low energy secondary electrons. At high ion velocities v p (i.e. v p > 10 7 cm/s) the kinetic emission of electrons as a result of direct Coulomb interaction between the ion and the target electron is the dominant initial production mechanism. The energy lost by the ion and, thus, transferred to the electrons is known as electronic stopping power in the solid. Elastic and inelastic interactions of primary, liberated electrons on their way through the bulk and the surface of the solid modify strongly their original energy and angular distribution and, in particular, leads to the transfer of their energy to further, i.e. secondary electrons (SE), such that the main part of the deposited energy of the ion is eventually over transferred to SE. It is, therefore, suggestive to assume a proportionality between the electronic stopping power S sm-bullet of the ion and the total SE yield g, i.e. the number of electrons ejected per ion. Following Sternglass the authors consider schematically for kinetic SE emission contributions from two extreme cases: (a) SEs produced mostly isotropically with large impact parameter, associated with an escape depth L SE from the solid; (b) SEs produced mostly unisotropically in forward direction with small impact parameter (δ-electrons), associated with a transport length L δ

  2. Examining real-time time-dependent density functional theory nonequilibrium simulations for the calculation of electronic stopping power

    Science.gov (United States)

    Yost, Dillon C.; Yao, Yi; Kanai, Yosuke

    2017-09-01

    In ion irradiation processes, electronic stopping power describes the energy transfer rate from the irradiating ion to the target material's electrons. Due to the scarcity and significant uncertainties in experimental electronic stopping power data for materials beyond simple solids, there has been growing interest in the use of first-principles theory for calculating electronic stopping power. In recent years, advances in high-performance computing have opened the door to fully first-principles nonequilibrium simulations based on real-time time-dependent density functional theory (RT-TDDFT). While it has been demonstrated that the RT-TDDFT approach is capable of predicting electronic stopping power for a wide range of condensed matter systems, there has yet to be an exhaustive examination of the physical and numerical approximations involved and their effects on the calculated stopping power. We discuss the results of such a study for crystalline silicon with protons as irradiating ions. We examine the influences of key approximations in RT-TDDFT nonequilibrium simulations on the calculated electronic stopping power, including approximations related to basis sets, finite size effects, exchange-correlation approximation, pseudopotentials, and more. Finally, we propose a simple and efficient correction scheme to account for the contribution from core-electron excitations to the stopping power, as it was found to be significant for large proton velocities.

  3. Average stopping powers for electron and photon sources for radiobiological modeling and microdosimetric applications

    Science.gov (United States)

    Vassiliev, Oleg N.; Kry, Stephen F.; Grosshans, David R.; Mohan, Radhe

    2018-03-01

    This study concerns calculation of the average electronic stopping power for photon and electron sources. It addresses two problems that have not yet been fully resolved. The first is defining the electron spectrum used for averaging in a way that is most suitable for radiobiological modeling. We define it as the spectrum of electrons entering the sensitive to radiation volume (SV) within the cell nucleus, at the moment they enter the SV. For this spectrum we derive a formula that combines linearly the fluence spectrum and the source spectrum. The latter is the distribution of initial energies of electrons produced by a source. Previous studies used either the fluence or source spectra, but not both, thereby neglecting a part of the complete spectrum. Our derived formula reduces to these two prior methods in the case of high and low energy sources, respectively. The second problem is extending electron spectra to low energies. Previous studies used an energy cut-off on the order of 1 keV. However, as we show, even for high energy sources, such as 60Co, electrons with energies below 1 keV contribute about 30% to the dose. In this study all the spectra were calculated with Geant4-DNA code and a cut-off energy of only 11 eV. We present formulas for calculating frequency- and dose-average stopping powers, numerical results for several important electron and photon sources, and tables with all the data needed to use our formulas for arbitrary electron and photon sources producing electrons with initial energies up to  ∼1 MeV.

  4. Defect creation by swift heavy ions: materials modifications in the electronic stopping power regime

    International Nuclear Information System (INIS)

    Toulemonde, M.

    1994-01-01

    The material modifications by swift heavy ions in the electronic stopping power regime are puzzling question: How the energy deposited on the electrons can induced material modifications? In order to answer to this question, the modifications induced in non-radiolytic materials are described and compared to the predictions. In first part the main experimental observations is presented taking into account the irradiation parameters. Then it is shown that the initial phases of the material are very important. Amorphous materials, whatever it is a metal, a semiconductor or an insulator, are till now all sensitive to the high electronic excitation induced by the slowing down of a swift heavy ion. All oxide materials, insulators or conductors, are also sensitive even the MgO, one of most famous exceptions. Crystalline metals or semiconductors are intermediate cases: some are insensitive like Cu and Si respectively while Fe and GeS are sensitive. The main feature is the different values of the electronic stopping power threshold of material modifications. The evolution of the damage creation is described showing that the damage morphology seems to be the same whatever the material is amorphous or crystalline. In second part a try of interpretation of the experimental results will be done on the behalf of the two following models: The Coulomb spike and the thermal spike models. It will be shown that there is some agreement with limited predictions made in the framework of the Coulomb spike model. But it appears that the thermal spike model can account for most of the experimental data using only one free parameter: The electron-phonon strength which is a physical characteristic of the irradiated material. (author). 4 figs., 1 tab., 64 refs

  5. Calculation of electronic stopping power along glancing swift heavy ion tracks in perovskites using ab initio electron density data

    Energy Technology Data Exchange (ETDEWEB)

    Osmani, O; Duvenbeck, A; Akcoeltekin, E; Meyer, R; Schleberger, M [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany); Lebius, H [CIMAP, blvd Henri Becquerel, 14070 Caen (France)], E-mail: marika.schleberger@uni-due.de

    2008-08-06

    In recent experiments the irradiation of insulators of perovskite type with swift (E{approx}100 MeV) heavy ions under glancing incidence has been shown to provide a unique means to generate periodically arranged nanodots at the surface. The physical origin of these patterns has been suggested as stemming from a highly anisotropic electron density distribution within the bulk. In order to show the relevance of the electron density distribution of the target we present a model calculation for the system Xe{sup 23+} {yields} SrTiO{sub 3} that is known to produce the aforementioned surface modifications. On the basis of the Lindhard model of electronic stopping, we employ highly-resolved ab initio electron density data to describe the conversion of kinetic energy into excitation energy along the ion track. The primary particle dynamics are obtained via integration of the Newtonian equations of motion that are governed by a space- and time-dependent frictional force originating from Lindhard stopping. The analysis of the local electronic stopping power along the ion track reveals a pronounced periodic structure. The periodicity length varies strongly with the particular choice of the polar angle of incidence and is directly correlated to the experimentally observed formation of periodic nanodots at insulator surfaces.

  6. Electronic stopping power calculation for water under the Lindhard formalism for application in proton computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, A. F., E-mail: afguerreror@uqvirtual.edu.co [Departamento de Física, Universidad Del Quindío Cra 15 # 12N Armenia, Quindío (Colombia); Mesa, J., E-mail: jmesa@ibb.unesp.br [Instituto de Biociências de Botucatu da UNESP Distrito de Rubião Jr. s/n°, 18618-000, Botucatu, SP (Brazil)

    2016-07-07

    Because of the behavior that charged particles have when they interact with biological material, proton therapy is shaping the future of radiation therapy in cancer treatment. The planning of radiation therapy is made up of several stages. The first one is the diagnostic image, in which you have an idea of the density, size and type of tumor being treated; to understand this it is important to know how the particles beam interacts with the tissue. In this work, by using de Lindhard formalism and the Y.R. Waghmare model for the charge distribution of the proton, the electronic stopping power (SP) for a proton beam interacting with a liquid water target in the range of proton energies 10{sup 1} eV - 10{sup 10} eV taking into account all the charge states is calculated.

  7. Electronic stopping powers for fluorine ions in {sup 19}F{sup +}-implanted AgGaS{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiangdong; Xia Yueyuan; Lu Qingming; Li Feng; Huang Boda

    2004-01-15

    Electronic stopping powers for 80-350 keV {sup 19}F ions in AgGaS{sub 2} were obtained by range measurement. Depth profiles of {sup 19}F in AgGaS{sub 2} were measured by using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonant nuclear reaction at E{sub R}=872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross sections were compared with those obtained from Monte Carlo simulation codes.

  8. Electronic stopping powers for fluorine ions in 19F+-implanted AgGaS2 crystal

    International Nuclear Information System (INIS)

    Liu Xiangdong; Xia Yueyuan; Lu Qingming; Li Feng; Huang Boda

    2004-01-01

    Electronic stopping powers for 80-350 keV 19 F ions in AgGaS 2 were obtained by range measurement. Depth profiles of 19 F in AgGaS 2 were measured by using the 19 F(p,αγ) 16 O resonant nuclear reaction at E R =872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross sections were compared with those obtained from Monte Carlo simulation codes

  9. ESTAR, PSTAR, ASTAR. A PC package for calculating stopping powers and ranges of electrons, protons and helium ions. Version 2

    International Nuclear Information System (INIS)

    Berger, M.J.

    1993-01-01

    A PC package is documented for calculating stopping powers and ranges of electrons, protons and helium ions in matter for energies from 1 keV up to 10 GeV. Stopping powers and ranges for electrons can be calculated for any element, compound or mixture. Stopping powers and ranges of protons and helium ions can be calculated for 74 materials (26 elements and 48 compounds and mixtures). The files are stored on two HD diskettes in compressed form. Both executable files for IBM PC and Fortran-77 source files are provided. All three programs require 5.2 Mb of disk space. This set of two diskettes with detailed documentation is available upon request, cost free, from the IAEA Nuclear Data Section. (author). 25 refs, 4 tabs

  10. Calculation of inelastic mean free path and stopping power for electrons in solids from an optical-data model

    International Nuclear Information System (INIS)

    Fernandez-Varea, J.M.; Mayol, R.; Salvat, F.; Liljequist, D.

    1992-11-01

    The numerical calculation of electron inelastic mean free path and stopping power from an optical-data model recently proposed by Fernandez-Varea et al. is described in detail. Explicit expressions for the one-electron total cross sections of the two-modes model of the free-electron gas and the δ-oscillator are derived. The inelastic mean free path and the stopping power are obtained as integrals of these one-electron total cross sections weighted by the optical as integrals of these one-electron total cross sections weighted by the optical oscillator strength. The integrals can be easily evaluated, with a selected accuracy, by using the FORTRAN 77 subroutine GABQ described here, which implements a 20-points Gauss adaptive bipartition quadrature method. Source listings of FORTRAN 77 subroutines to compute the one-electron total cross sections are also given

  11. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons

    International Nuclear Information System (INIS)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internal contamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy 109 Cd conversion electrons, working with a 4 π proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin 109 Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  12. The gaseous emission of polymers under swift heavy ion irradiation: effect of the electronic stopping power

    International Nuclear Information System (INIS)

    Picq, V.

    2000-07-01

    This thesis contributes to a better understanding of the damaging processes, which occur in polymers under swift heavy ion irradiation. The present study is exclusively devoted to the influence of the electronic stopping power, (dE/dx)e, on the molecular emission under irradiation. The irradiated polymers are polyethylene, polypropylene and poly-butene. The (dE/dx)e of the projectiles used varies from 3.5*10 -3 MeV.mg -1 .cm 2 (electron) to 39 MeV.mg -1 .cm 2 ( 58 Ni). We used two different experimental approaches in order to identify the nature of the emitted gases: mass spectrometry and infrared spectroscopy. The first technique is non selective, therefore, we could detect the emission of H 2 and heavy molecules; it also gives information on the diffusion kinetics of the molecules formed. The use of infrared spectroscopy for this kind of analysis is new and the technique was developed at the laboratory. It enables us to identify, without any ambiguity, molecules with up to three carbon atoms. The experimental spectra are analysed by using reference spectra of pure gases, measured in our laboratory. We have quantified precisely each identified gas, and we have followed the evolution of the radiochemical yields with increasing (dE/dx)e. The results, obtained at different (dE/dx)e, inform us on the different mechanisms of gas molecules formation, for example the side group departure and, at high (dE/dx)e, the fragmentation of the main chain which is due to multiple ionisation of the macromolecule. (author)

  13. Projectile- and charge-state-dependent electron yields from ion penetration of solids as a probe of preequilibrium stopping power

    DEFF Research Database (Denmark)

    Rothard, H.; Schou, Jørgen; Groeneveld, K.-O.

    1992-01-01

    Kinetic electron-emission yields gamma from swift ion penetration of solids are proportional to the (electronic) stopping power gamma approximately Beta-S*, if the preequilibrium evolution of the charge and excitation states of the positively charged ions is taken into account. We show...... by investigating the "transport factor" beta, the energy spectrum of directly ejected recoil electrons and the evolution of ionic charge state inside solids. Estimates of the energy-loss fraction leading to electron emission and the effective charges of the ions near the surface allow a quantitative description...

  14. Measurement of stopping power of heavy ions

    International Nuclear Information System (INIS)

    Kitahara, Tetsuo

    1981-01-01

    The stopping power of heavy ions is discussed. In the low energy region, heavy ions keep some of their orbital electrons, and have equilibrium electron charge. The stopping power of penetrating particles depends on this effective charge. At present, it is hard to estimate this effective charge theoretically, accordingly, the estimation is made experimentally. Another difficulty in this estimation is that the Born approximation is not effective for heavy ions. In the low energy region, electronic stopping and nuclear stopping contribute to the stopping power. For the electronic stopping, a formula for the stopping power was given by Lindhard et al. The experimental values were obtained at GSI, and are inconsistent with the estimation by the Lindhard's formula. In the high energy region, where the Born approximation can be used, the Bethe's formula is applied, but the experimental data are scarce. Oscillations are seen in the Z dependence graph of the experimental stopping cross sections. Experimental works on the stopping power have been done. The differential and the integral methods were carried out. (Kato, T.)

  15. Current stopping power analyses

    International Nuclear Information System (INIS)

    Porter, L.E.

    1983-01-01

    Modified Bethe-Bloch stopping power theory permits fairly accurate calculation of energy losses over a broad interval of projectile velocity v = νc insofar as several parameters appearing in the revised Bethe-Bloch formula have been corectly evaluated. Since the parameters cannot in general be ascertained by calculation from first principles, fits of theory to measurement remain the best method of evaluation. The parameters alluded to are: the target mean excitation energy; the shell correction scaling parameters; the composite single free parameter of the Barkas (projectile-z 3 ) effect correction formalism, and the strength of the correction term; the high velocity density effect correction parameter; and the low velocity charge state parameter. These parameters are discussed

  16. Measurement of mass stopping power of chitosan polymer loaded with TiO2 for relativistic electron interaction

    Science.gov (United States)

    Babu, S. Ramesh; Badiger, N. M.; Karidurgannavar, M. Y.; Varghese, Jolly. G.

    2018-04-01

    The Mass Stopping Power (MSP) of relativistic electrons in chitosan loaded with TiO2 of different proportions has been measured by recording the spectrum of internal conversion electrons. The internal conversion electrons of energies 614 keV from Cs137, 942 keV and 1016 keV from Bi207 source are allowed to pass through chitosan-TiO2 alloy and transmitted electrons are detected with a Si (Li) detector coupled to an 8 K multichannel analyzer. By knowing the energies of incident electrons and transmitted electrons, the energy loss and the MSP are determined. Thus measured MSP values of the alloys are compared with the values calculated using Braggs additivity rule. The disagreement between theory and experiment is found to increases with increasing TiO2 concentration in chitosan, indicating the influence of chemical environment in the properties of such polymeric membrane.

  17. Stopping power and energy loss cross section of a point charge penetrating through a dense medium of bound electrons

    International Nuclear Information System (INIS)

    Belkacem, A.; Sigmund, P.; Odense Univ.

    1989-01-01

    We have derived the dielectric function ε(k,ω) in the Lindhard approximation for a medium consisting of electrons individually bound by harmonic forces. The dielectric function is expressible in terms of a hypergeometric series and approaches well-known results in the limits of negligible binding, large momentum transfer, and long wavelength, respectively. The stopping power of a moving point charge scales very well with the shifted resonance frequency α 0 = (ω O 2 + ω P 2 ) 1/2 (ω O = oscillator frequency; ω P = plasma frequency) that follows from classical dispersion theory. The results differ noticeably from free-electron behavior even at rather high electron density. The discrete excitation levels of an isolated harmonic oscillator are increasingly shifted and broadened with increasing electron density. 15 refs., 2 figs

  18. Calculation of the collision stopping power of simple and composed materials for fast electrons considering the density effect with the aid of effective material parameters

    International Nuclear Information System (INIS)

    Geske, G.

    1979-01-01

    With the aid of two effective material parameters a simple expression is presented for the Bethe-Bloch-formula for the calculation of the collision stopping power of materials for fast electrons. The formula has been modified in order to include the density effect. The derivation was accomplished in connection with a formalism given by Kim. It was shown that the material dependence on the collision stopping power is entirely comprehended by the density and two effective material parameters. Thus a simple criterion is given for the comparison of materials as to their collision stopping power

  19. Evidences of the influence of the electronic stopping power in the elastic energy loss in thin films of amorphous carbon

    International Nuclear Information System (INIS)

    Grande, P.L.; Fichtner, P.F.P.; Behar, M.; Zawislak, E.F.C.

    1988-01-01

    Measurements of deepness of implanted ions in carbon films, show the possibility that the energy elastic component given to the medium, could be affected by the ineslastic stopping parcel, which could cause a total stopping power, smaller than the expected. (A.C.A.S.) [pt

  20. Theoretical study of the electron stopping power in ion planar channeling

    International Nuclear Information System (INIS)

    Haymann, P.

    1974-01-01

    A theory recently developed by the authors for slow and fast electrons is shown to be also applicable to channeled ions and to explain the experimental results about electron loss phenomena as a whole. The theory is based on the fundamental hypothesis of the nonadiabaticity of the ion-target interactions. How essential an exponential form of the interaction pseudo-potential is in explaining the energy exchange mechanism at the walls may be deduced from a quasi-classical development of the quantum model. The theory also allows a number of new experiments to be envisaged in the field of surface electron states [fr

  1. Empirical stopping powers for ions in solids

    International Nuclear Information System (INIS)

    Ziegler, J.F.; Biersack, J.P.; Littmark, U.

    1983-01-01

    The work of Brandt and collaborators on low energy ion stopping powers has been extended to create an empirical formulation for the stopping of ions in solids. The result is a simple computer program (about 60 lines of code) which calculates stopping powers from zero to 100 MeV/amu for all ions in all elemental solids. This code has been compared to the data in about 2000 papers, and has a standard error of 9% for energies above keV/amu. This approach includes high energy relativistic effects and shell-corrections. In the medium energy range it uses stopping theory based on the local-density approximation and Lindhard stopping in a free electron gas. This is applied to realistic Hartree-Fock charge distributions for crystalline solids. In the low energy range it uses the Brandt concepts of ion stripping relative to the Fermi velocity of solids, and also his formalism for the relation of projectile ionization to its effective charge. The details of the calculation are presented, and a broad comparison is shown with experiment. Special comparative examples are shown of both the low energy stopping power oscillations which depend on the atomic number of the ion, and also of the target

  2. Procedures for the selection of stopping power ratios for electron beams: Comparison of IAEA TRS procedures and of DIN procedures with Monte Carlo results

    International Nuclear Information System (INIS)

    Roos, M.; Christ, G.

    2000-01-01

    In the International Code of Practice IAEA TRS-381 the stopping power ratios water/air are selected according to the half-value depth and the depth of measurement. In the German Standard DIN 6800-2 a different procedure is recommended, which, in addition, takes the practical electron range into account; the stopping power data for monoenergetic beams from IAEA TRS-381 are used. Both procedures are compared with recent Monte Carlo calculations carried out for various beams of clinical accelerators. It is found that the DIN procedure shows a slightly better agreement. In addition, the stopping power ratios in IAEA TRS-381 are compared with those in DIN 6800-2 for the reference conditions of the beams from the PTB linac; the maximum deviation is not larger than 0.6%. (author)

  3. Mean free paths by inelastic interactions, stopping powers, and energy straggling for electrons of energies up to 20 keV in various solids

    International Nuclear Information System (INIS)

    Akkerman, A.F.; Chernov, G.Ya.

    1978-01-01

    For the elements C, Be, Mg, Al, Si, K, Ge, Sb, Bi calculations of the mean free paths and stopping powers of low energy electrons are performed. In the computational model Lindhard's formalism of the dielectric response function for pair and plasmon excitation and the classical cross-section for ionization processes are used. Anomalously high mean free paths and small stopping powers in potassium are found. This behaviour which is connected with low electron concentration in the valence band is expected to hold for all alkali metals. For energies above 10 keV the calculated dE/dx agree well with values calculated from the Bethe-Bloch formula. A Monte-Carlo method is used for the calculation of the energy loss distribution of electrons passing through thin targets. It is noted that Blunck-Leisegang's theory fails to render the energy straggling at electron energies below 10 keV. (author)

  4. Stopping power, its meaning, and its general characteristics

    International Nuclear Information System (INIS)

    Inokuti, Mitio.

    1995-01-01

    This essay presents remarks on the meaning of stopping, power and of its magnitude. More precisely, the first set of remarks concerns the connection of stopping power with elements of particle-transport theory, which describes particle transport and its consequences in full detail, including its stochastic aspects. The second set of remarks concerns the magnitude of the stopping power of a material and its relation with the material's electronic structure and other properties

  5. SU-C-201-07: Towards Clinical Cherenkov Emission Dosimetry: Stopping Power-To-Cherenkov Power Ratios and Beam Quality Specification of Clinical Electron Beams

    International Nuclear Information System (INIS)

    Zlateva, Y; Seuntjens, J; El Naqa, I

    2016-01-01

    Purpose: We propose a Cherenkov emission (CE)-based reference dosimetry method, which in contrast to ionization chamber-based dosimetry, employs spectrum-averaged electron restricted mass collision stopping power-to-Cherenkov power ratios (SCRs), and we examine Monte Carlo-calculated SCRs and beam quality specification of clinical electron beams. Methods: The EGSnrc user code SPRRZnrc was modified to compute SCRs instead of stopping-power ratios (single medium: water; cut-off: CE threshold (observing Spencer-Attix conditions); CE power: Frank-Tamm). SCRs are calculated with BEAMnrc for realistic electron beams with nominal energies of 6–22 MeV from three Varian accelerators (TrueBeam Clinac 21EX, Clinac 2100C/D) and for mono-energetic beams of energies equal to the mean electron energy at the water surface. Sources of deviation between clinical and mono-energetic SCRs are analyzed quantitatively. A universal fit for the beam-quality index R_5_0 in terms of the depth of 50% CE C_5_0 is carried out. Results: SCRs at reference depth are overestimated by mono-energetic values by up to 0.2% for a 6-MeV beam and underestimated by up to 2.3% for a 22-MeV beam. The variation is mainly due to the clinical beam spectrum and photon contamination. Beam angular spread has a small effect across all depths and energies. The influence of the electron spectrum becomes increasingly significant at large depths, while at shallow depths and high beam energies photon contamination is predominant (up to 2.0%). The universal data fit reveals a strong linear correlation between R_5_0 and C_5_0 (ρ > 0.99999). Conclusion: CE is inherent to radiotherapy beams and can be detected outside the beam with available optical technologies, which makes it an ideal candidate for out-of-beam high-resolution 3D dosimetry. Successful clinical implementation of CE dosimetry hinges on the development of robust protocols for converting measured CE to radiation dose. Our findings constitute a key step

  6. Ion Stopping Powers and Ranges Whenever You Need Them

    DEFF Research Database (Denmark)

    Bassler, Niels; Christensen, Casper; Tørresø, Jesper Rosholm

    A new app "Electronic Stopping Power" for Android mobile phones and tablets, looks up stopping powers using the ICRU 49 (protons and alphas) and the revised ICRU 73 (lithium and heavier ions) tables. In addition, also MSTAR and an implementation of the Bethe equation expanded to low energies...

  7. Measurements of output factors with different detector types and Monte Carlo calculations of stopping-power ratios for degraded electron beams

    International Nuclear Information System (INIS)

    Bjoerk, Peter; Knoeoes, Tommy; Nilsson, Per

    2004-01-01

    The aim of the present study was to investigate three different detector types (a parallel-plate ionization chamber, a p-type silicon diode and a diamond detector) with regard to output factor measurements in degraded electron beams, such as those encountered in small-electron-field radiotherapy and intraoperative radiation therapy (IORT). The Monte Carlo method was used to calculate mass collision stopping-power ratios between water and the different detector materials for these complex electron beams (nominal energies of 6, 12 and 20 MeV). The diamond detector was shown to exhibit excellent properties for output factor measurements in degraded beams and was therefore used as a reference. The diode detector was found to be well suited for practical measurements of output factors, although the water-to-silicon stopping-power ratio was shown to vary slightly with treatment set-up and irradiation depth (especially for lower electron energies). Application of ionization-chamber-based dosimetry, according to international dosimetry protocols, will introduce uncertainties smaller than 0.3% into the output factor determination for conventional IORT beams if the variation of the water-to-air stopping-power ratio is not taken into account. The IORT system at our department includes a 0.3 cm thin plastic scatterer inside the therapeutic beam, which furthermore increases the energy degradation of the electrons. By ignoring the change in the water-to-air stopping-power ratio due to this scatterer, the output factor could be underestimated by up to 1.3%. This was verified by the measurements. In small-electron-beam dosimetry, the water-to-air stopping-power ratio variation with field size could mostly be ignored. For fields with flat lateral dose profiles (>3 x 3 cm 2 ), output factors determined with the ionization chamber were found to be in close agreement with the results of the diamond detector. For smaller field sizes the lateral extension of the ionization chamber

  8. Measurements of output factors with different detector types and Monte Carlo calculations of stopping-power ratios for degraded electron beams.

    Science.gov (United States)

    Björk, Peter; Knöös, Tommy; Nilsson, Per

    2004-10-07

    The aim of the present study was to investigate three different detector types (a parallel-plate ionization chamber, a p-type silicon diode and a diamond detector) with regard to output factor measurements in degraded electron beams, such as those encountered in small-electron-field radiotherapy and intraoperative radiation therapy (IORT). The Monte Carlo method was used to calculate mass collision stopping-power ratios between water and the different detector materials for these complex electron beams (nominal energies of 6, 12 and 20 MeV). The diamond detector was shown to exhibit excellent properties for output factor measurements in degraded beams and was therefore used as a reference. The diode detector was found to be well suited for practical measurements of output factors, although the water-to-silicon stopping-power ratio was shown to vary slightly with treatment set-up and irradiation depth (especially for lower electron energies). Application of ionization-chamber-based dosimetry, according to international dosimetry protocols, will introduce uncertainties smaller than 0.3% into the output factor determination for conventional IORT beams if the variation of the water-to-air stopping-power ratio is not taken into account. The IORT system at our department includes a 0.3 cm thin plastic scatterer inside the therapeutic beam, which furthermore increases the energy degradation of the electrons. By ignoring the change in the water-to-air stopping-power ratio due to this scatterer, the output factor could be underestimated by up to 1.3%. This was verified by the measurements. In small-electron-beam dosimetry, the water-to-air stopping-power ratio variation with field size could mostly be ignored. For fields with flat lateral dose profiles (>3 x 3 cm2), output factors determined with the ionization chamber were found to be in close agreement with the results of the diamond detector. For smaller field sizes the lateral extension of the ionization chamber hampers

  9. Stopping-power ratios for dosimetry

    International Nuclear Information System (INIS)

    Andreo, P.

    1988-01-01

    The determination of the absorbed dose at a specified location in a medium irradiated with an electron or photon beam normally consists of two steps: (1) the determination of the mean absorbed dose to a detector by using a calibration factor or performing an absolute measurement, (2) the determination of the absorbed dose to the medium at the point of interest by calculations based on the knowledge of the absorbed dose to the detector and the different stopping and scattering properties of the medium and the detector material. When the influence of the detector is so small that the electron fluence in the medium is not modified, the ratio of the mass collision stopping power of the two materials accounts for the differences in energy deposition, and provides a conversion factor to relate the absorbed dose in both materials. Today, all national and international dosimetry protocols and codes of practice are based on such procedures, and the user easily can carry out these steps using tabulated data to convert a measured quantity to absorbed dose in the irradiated medium at the location of interest. Effects due to the spatial extension of the detector are taken into account using perturbation correction factors. The Monte Carlo method has become the most common and powerful calculational technique for determining the electron fluence (energy spectra) under different irradiation conditions. Cavity theory is then used to calculate stopping-power ratios. In this chapter, the different steps needed to evaluate s-ratios will be considered, emphasizing the different types of cavity-theory integrals and the Monte Carlo techniques used to derive the necessary electron spectra in the range of energies commonly used in radiation dosimetry, i.e., photon and electron beams with energies up to 50 MeV

  10. A new calculation on the stopping power and mean free path for low energy electrons in toluene over energy range of 20-10 000 eV

    International Nuclear Information System (INIS)

    Tan Zhenyu; Xia Yueyuan; Liu Xiangdong; Zhao Mingwen; Zhang Liming

    2009-01-01

    A new calculation of the stopping powers (SP) and inelastic mean free paths (IMFP) for electrons in toluene at energies below 10 keV has been presented. The calculation is based on the dielectric model and on an empirical evaluation approach of optical energy loss function (OELF). The reliability for the evaluated OELFs of several hydrocarbons with available experimental optical data has been systematically checked. For toluene, using the empirical OELF, the evaluated mean ionization potential, is compared with that given by Bragg's rule, and the calculated SP at 10 keV is also compared with the Bethe-Bloch prediction. The present results for SP and IMFP provide an alternative basic data for the study on the energy deposition of low-energy electrons transport through toluene, and also show that the method used in this work may be a good one for evaluating the SP and IMFP for hydrocarbons

  11. Measurement of the Barkas effect around the stopping-power maximum for light and heavy targets

    International Nuclear Information System (INIS)

    Moeller, S.P.; Knudsen, H.; Mikkelsen, U.; Paludan, K.; Morenzoni, E.

    1997-01-01

    The first direct measurements of antiproton stopping powers around the stopping power maximum are presented. The LEAR antiproton-beam of 5.9 MeV is degraded to 50-700 keV, and the energy-loss is found by measuring the antiproton velocity before and after the target. The antiproton stopping powers of Si and Au are found to be reduced by 30 and 40% near the electronic stopping power maximum as compared to the equivalent proton stopping power. The Barkas effect, that is the stopping power difference between protons and antiprotons, is extracted and compared to theoretical estimates. (orig.)

  12. Electronic stopping power of slow H{sup +} and He{sup 2+} ions in CdTe from first principle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chang-kai [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Mao, Fei [School of Nuclear Science and Technology, University of South China, Hengyang 421001 (China); Fu, Yan-long; Liao, Bin [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ouyang, Xiao-ping [Northwest Institute of Nuclear Technology, Xi’an 710024 (China); Zhang, Feng-Shou, E-mail: fszhang@bnu.edu.cn [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China)

    2017-02-01

    We study through time-dependent density-functional theory (TDDFT) method the electronic stopping power of low-energy protons and helium ions moving through CdTe under the condition of channeling. The agreement between our calculated results and SRIM data roughly up to the stopping maximum for the proton along the 〈1 0 0〉 and 〈1 1 1〉 crystalline axes and for helium ions along 〈1 0 0〉 crystalline axis is satisfactory, which can be explained by the energy transfer mechanism that electron–hole excitation caused by ions in the solid. However, in the channel of 〈1 1 1〉 for helium ions, a transition between two velocities regimes is observed at about v = 0.4 a.u. This may be an indication of extra energy loss channel beyond the electron–hole excitation. To analyze it, we calculate the amount of electrons captured by the moving projectiles in real time. It is found that the soft transition between two velocities regimes can be attributed to the charge transfer and charge resonance between helium ion and host atoms of CdTe crystal, which are considered as additional energy loss channels.

  13. Stopping Power Measurements: Implications in Nuclear Astrophysics

    International Nuclear Information System (INIS)

    Carmen Angulo; Thierry Delbar; Jean-Sebastien Graulich; Pierre Leleux

    1999-01-01

    The stopping powers of C, CH 2 , Al, Ni, and polyvinylchloride (PVC) for several light ions ( 9 Be, 11 B, 12 C, 14 N, 16 O, 19 F, 20 Ne) with an incident energy of 1 MeV/amu have been measured at the Louvain-la-Neuve cyclotron facility. Stopping powers are given relative to the one for 5.5 MeV 4 He ions with an uncertainty of less than 1%. We compare our results with two widely used semiempirical models and we discuss some implications in nuclear astrophysics studies

  14. Range and stopping power for slow particles

    International Nuclear Information System (INIS)

    Bastiano, M.; Fernandez, J. E.; Molinari, V. G.

    1997-01-01

    Generally, the effects of thermal agitation and chemical bonding of the target atoms need to be taken into account to compute properly the range and stopping power of particles. These two effects, however, complicate very much the calculation of the above parameters, and for this reason are usually neglected. In fact, when the energy of the test particles (t.p.) is sufficiently high compared to the thermal or bonding energies, these two effects can be safely disregarded. When the energy of the t.p. is of the same order of the thermal agitation or the chemical bonding, on the other hand, such approximation is not realistic, and to obtain meaningful results one must take into account the velocity distribution of the field particles (f.p.). The aim of this paper is to present a simple model describing the transport of particles (e.g., electrons) in the thermal zone, considering the thermal agitation of f.p. with an arbitrary distribution. It will be shown that in the first part of the slowing down the kinetic energy of t.p. is partially transformed into temperature. In the second part, the temperature tends to reach the equilibrium temperature, while average velocity of t.p. becomes zero. (author)

  15. Effects of electronic and nuclear stopping power on disorder induced in GaN under swift heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Moisy, F., E-mail: moisy@ganil.fr [CIMAP, Normandie Universite ENSICAEN/CEA/CNRS, 6 Bd Maréchal Juin, 14050 Caen (France); Sall, M.; Grygiel, C.; Balanzat, E.; Boisserie, M.; Lacroix, B. [CIMAP, Normandie Universite ENSICAEN/CEA/CNRS, 6 Bd Maréchal Juin, 14050 Caen (France); Simon, P. [CNRS, UPR 3079 CEMHTI, CS 90055, 45071 Orléans Cedex 2 (France); Monnet, I. [CIMAP, Normandie Universite ENSICAEN/CEA/CNRS, 6 Bd Maréchal Juin, 14050 Caen (France)

    2016-08-15

    Wurtzite GaN epilayers, grown on the c-plane of sapphire substrate, have been irradiated with swift heavy ions at different energies and fluences, and thereafter studied by Raman scattering spectroscopy, UV–visible spectroscopy and transmission electron microscopy. Raman spectra show strong structural modifications in the GaN layer. Indeed, in addition to the broadening of the allowed modes, a large continuum and three new modes at approximately 200 cm{sup −1}, 300 cm{sup −1} and 670 cm{sup −1} appear after irradiation attributed to disorder-activated Raman scattering. In this case, spectra are driven by the phonon density of states of the material due to the loss of translation symmetry of the lattice induced by defects. It was shown qualitatively that both electronic excitations and elastic collisions play an important role in the disorder induced by irradiation. UV–visible spectra reveal an absorption band at 2.8 eV which is linked to the new mode at 300 cm{sup −1} observed in irradiated Raman spectra and comes from Ga-vacancies. These color centers are produced by elastic collisions (without any visible effect of electronic excitations).

  16. Seismic stops for nuclear power plants

    International Nuclear Information System (INIS)

    Cloud, R.L.; Leung, J.S.M.; Anderson, P.H.

    1989-01-01

    In the regulated world of nuclear power, the need to have analytical proof of performance in hypothetical design-basis events such as earth quakes has placed a premium on design configurations that are mathematically tractable and easily analyzed. This is particularly true for the piping design. Depending on how the piping analyses are organized and on how old the plant is, there may be from 200 to 1000 separate piping runs to be designed, analyzed, and qualified. In this situation, the development of snubbers seemed like the answer to a piping engineer's prayer. At any place where seismic support was required but thermal motion had to be accommodated, a snubber could be specified. But, as experience has now shown, the program was solved only on paper. This article presents an alternative to conventional snubbers. These new devices, termed Seismic Stops are designed to replace snubbers directly and look like snubbers on the outside. But their design is based on a completely different principle. The original concept has adapted from early seismic-resistant pipe support designs used on fossil power plants in California. The fundamental idea is to provide a space envelope in which the pipe can expand freely between the hot and cold positions, but cannot move outside the envelope. Seismic Stops are designed to transmit any possible impact load, as would occur in an earthquake, away from the pipe itself to the Seismic Stop. The Seismic Stop pipe support is shown

  17. Simulations of enhanced ion stopping power experiments

    International Nuclear Information System (INIS)

    Mehlhorn, T.A.; Maenchen, J.E.; Olsen, J.N.; Johnson, D.J.

    1984-01-01

    As the material in an ICF target is heated and ionized by an intense ion beam, the ion stopping power changes from that of neutral atoms. This changes the energy deposition characteristics of the ion beam and thereby can profoundly influence the target dynamics. An accurate ion energy deposition model is important for designing ICF targets that perform in an optimal fashion. An experiment to measure a time-resolved ion stopping power history in a partially ionized target is being fielded on the PROTO I accelerator at Sandia Labs. This experiment utilizes a voltage ramped Thomson parabola to provide a time-history of the ion energy incident upon and exiting from a cylindrical target foil

  18. Measurement of stopping power of light ions

    International Nuclear Information System (INIS)

    Sakamoto, Naoki

    1981-01-01

    The stopping power of light ions penetrating various materials has been measured. The data of proton stopping power and the mean ionization potentials are presented. The experiments were made by using the 6.75 MeV protons from a cyclotron and the protons in the energy range from 3 to 9 MeV from a tandem Van de Graaff. The windows with and without sample-foils were rotated in front of a semiconductor detector, and the measured energy loss and the thickness of the sample foils were used to estimate the energy loss at the mean energy of protons in the samples. The analyses were made by considering the inner shell correction, Z 1 3 correction and the Bloch correction. The mean ionization potentials were derived from the data. (Kato, T.)

  19. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

  20. Sci-Thur AM: YIS – 04: Stopping power-to-Cherenkov power ratios and beam quality specification for clinical Cherenkov emission dosimetry of electrons: beam-specific effects and experimental validation

    International Nuclear Information System (INIS)

    Zlateva, Yana; Seuntjens, Jan; El Naqa, Issam

    2016-01-01

    Purpose: To advance towards clinical Cherenkov emission (CE)-based dosimetry by investigating beam-specific effects on Monte Carlo-calculated electron-beam stopping power-to-CE power ratios (SCRs), addressing electron beam quality specification in terms of CE, and validating simulations with measurements. Methods: The EGSnrc user code SPRRZnrc, used to calculate Spencer-Attix stopping-power ratios, was modified to instead calculate SCRs. SCRs were calculated for 6- to 22-MeV clinical electron beams from Varian TrueBeam, Clinac 21EX, and Clinac 2100C/D accelerators. Experiments were performed with a 20-MeV electron beam from a Varian TrueBeam accelerator, using a diffraction grating spectrometer with optical fiber input and a cooled back-illuminated CCD. A fluorophore was dissolved in the water to remove CE signal anisotropy. Results: It was found that angular spread of the incident beam has little effect on the SCR (≤ 0.3% at d max ), while both the electron spectrum and photon contamination increase the SCR at shallow depths and decrease it at large depths. A universal data fit of R 50 in terms of C 50 (50% CE depth) revealed a strong linear dependence (R 2 > 0.9999). The SCR was fit with a Burns-type equation (R 2 = 0.9974, NRMSD = 0.5%). Below-threshold incident radiation was found to have minimal effect on beam quality specification (< 0.1%). Experiments and simulations were in good agreement. Conclusions: Our findings confirm the feasibility of the proposed CE dosimetry method, contingent on computation of SCRs from additional accelerators and on further experimental validation. This work constitutes an important step towards clinical high-resolution out-of-beam CE dosimetry.

  1. Sci-Thur AM: YIS – 04: Stopping power-to-Cherenkov power ratios and beam quality specification for clinical Cherenkov emission dosimetry of electrons: beam-specific effects and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Zlateva, Yana; Seuntjens, Jan; El Naqa, Issam [McGill University, Cedars Cancer Centre, University of Michigan (United States)

    2016-08-15

    Purpose: To advance towards clinical Cherenkov emission (CE)-based dosimetry by investigating beam-specific effects on Monte Carlo-calculated electron-beam stopping power-to-CE power ratios (SCRs), addressing electron beam quality specification in terms of CE, and validating simulations with measurements. Methods: The EGSnrc user code SPRRZnrc, used to calculate Spencer-Attix stopping-power ratios, was modified to instead calculate SCRs. SCRs were calculated for 6- to 22-MeV clinical electron beams from Varian TrueBeam, Clinac 21EX, and Clinac 2100C/D accelerators. Experiments were performed with a 20-MeV electron beam from a Varian TrueBeam accelerator, using a diffraction grating spectrometer with optical fiber input and a cooled back-illuminated CCD. A fluorophore was dissolved in the water to remove CE signal anisotropy. Results: It was found that angular spread of the incident beam has little effect on the SCR (≤ 0.3% at d{sub max}), while both the electron spectrum and photon contamination increase the SCR at shallow depths and decrease it at large depths. A universal data fit of R{sub 50} in terms of C{sub 50} (50% CE depth) revealed a strong linear dependence (R{sup 2} > 0.9999). The SCR was fit with a Burns-type equation (R{sup 2} = 0.9974, NRMSD = 0.5%). Below-threshold incident radiation was found to have minimal effect on beam quality specification (< 0.1%). Experiments and simulations were in good agreement. Conclusions: Our findings confirm the feasibility of the proposed CE dosimetry method, contingent on computation of SCRs from additional accelerators and on further experimental validation. This work constitutes an important step towards clinical high-resolution out-of-beam CE dosimetry.

  2. Stopping powers of solids for low-energy protons

    International Nuclear Information System (INIS)

    Ashley, J.C.; Ritchie, R.H.

    1984-01-01

    Electron gas models are useful approximations for describing the valence electron response of a solid to the passage of a charged particle. A simple free-electron gas model was used by Fermi and Teller to estimate the time required for a mesotron to be stopped in various solids. More recent work has employed the Lindhard dielectric response function, or approximations thereto, for calculations of the valence electron contributions to energy loss per unit pathlength for protons. Such calculations have generally shown rather poor agreement with experimental data for low-energy protons (velocity small compared to the Fermi velocity, v<< v/sub F/). The purpose of this paper is to draw attention to a recent calculation of the stopping power for slow protons using a density-functional formalism. These new results have been shown to give good agreement with experimental data and thus should provide valuable theoretical guidance in estimating stopping powers of solids for which no experimental data are available

  3. 10 blows that stopped nuclear power

    International Nuclear Information System (INIS)

    Komanoff, C.

    1991-01-01

    The author describes these 10 blows in chronological order, 1973 through 1981, namely: (1) Arab Oil Embargo; (2) India Explodes a Bomb; (3) NRC replaces AEC; (4) Fire at Browns Ferry; (5) General Electric and NRC Engineers switch Sides; (6) Amory Lovins Recasts the Energy Debate; (7) The Seabrook Occupation; (8) The Three Mile Island Accident; (9) Federal Reserve Tightens the Money Supply; and (1) Pacific Gas and Electric Co. Gets it Backwards at Diablo Canyon. he stops there, not including the Washington Public Power Supply fiasco and the Chernobyl disaster, feeling nuclear expansion was essentially foreclosed without them. Further, he feels nuclear power seems fated to be forever at the mercy of forces beyond its control

  4. Stopping power for heavy ions in low energy region

    International Nuclear Information System (INIS)

    Kitagawa, Mitsuo

    1983-01-01

    Review is made for the study on the power for stopping heavy ions. The studies on the power for stopping heavy ions passing through materials have been developed in the last twenty years due to the accuracy improvement in the data analysis of the power for stopping light ions, the requirement of data establishment on the power for stopping heavy ions from fusion research and the development of the experimental studies by heavy-ion accelerators. The relation between the analysis of the power for stopping heavy ions and the power for stopping light ions is described from the standpoint that the results on the power for stopping light ions serve as the guide for the study on the power for stopping heavy ions. Both at present and in future. The analysis of stopping power data with the accuracy from +-10 to 20 % is possible from the theoretical analysis of effective electric charge and its systematic table of the numerical data. The outline of the scaling rule on effective electric charge is discussed. The deviation of the experimental data from the scaling rule is discussed by comparing with the measured values of effective electric charge ratio. Various analyses of the power for stopping heavy ions are summarized. (Asami, T.)

  5. Power electronics

    Indian Academy of Sciences (India)

    Kishore Chatterjee

    This special issue of Sadhana is a compilation of papers selected from those presented at the 7th National Power. Electronics Conference (NPEC), held at the Indian Institute of Technology, Bombay, on 21–23 December 2015. From among the papers presented in NPEC-2017, selected papers were peer-reviewed for ...

  6. Determination of electronic stopping powers of 0.05–1 MeV/u {sup 131}Xe ions in C-, Ni- and Au-absorbers with calorimetric low temperature detectors

    Energy Technology Data Exchange (ETDEWEB)

    Echler, A., E-mail: artur.echler@iamp.physik.uni-giessen.de [GSI Helmholtz Center for Heavy Ion Research, Darmstadt (Germany); Institute for Atomic and Molecular Physics, University of Giessen (Germany); Institute for Physics, University of Mainz (Germany); Egelhof, P.; Grabitz, P. [GSI Helmholtz Center for Heavy Ion Research, Darmstadt (Germany); Institute for Physics, University of Mainz (Germany); Kettunen, H. [Department of Physics, University of Jyväskylä (Finland); Kraft-Bermuth, S. [Institute for Atomic and Molecular Physics, University of Giessen (Germany); Laitinen, M. [Department of Physics, University of Jyväskylä (Finland); Müller, K. [Institute for Atomic and Molecular Physics, University of Giessen (Germany); Rossi, M.; Trzaska, W.H.; Virtanen, A. [Department of Physics, University of Jyväskylä (Finland)

    2017-01-15

    A new experimental system for precise determination of electronic stopping powers of heavy ions has been set up at the accelerator laboratory of the University of Jyväskylä. The new setup, combining an established B-ToF system and an array of calorimetric low temperature detectors (CLTDs), has been used for the determination of electronic stopping powers of 0.05–1 MeV/u {sup 131}Xe ions in carbon, nickel and gold. Thereby advantage of the improved linearity and energy resolution of CLTDs as compared to the previously used ionization detector was taken to reduce energy calibration errors and to increase sensitivity for the energy loss determination, in particular at very low energies. The total uncertainties of 3–4% for C- and Ni-targets, and 5–7% for Au-targets, respectively, are dominated by the target properties, i.e. thickness determination and inhomogeneities. The results are compared to data from literature and to predictions of different theoretical computer codes. In the high energy part of the examined energy range the results are in good agreement with previously published data, while new stopping power data for very heavy ions in different Z{sub 2}-materials have been obtained at lower energies. Moreover, unexpectedly strong channeling effects for the transmission of the {sup 131}Xe ions in thin, partly polycrystalline nickel and gold target foils have been observed and investigated.

  7. The IAEA stopping power database, following the trends in stopping power of ions in matter

    Science.gov (United States)

    Montanari, C. C.; Dimitriou, P.

    2017-10-01

    The aim of this work is to present an overview of the state of art of the energy loss of ions in matter, based on the new developments in the stopping power database of the International Atomic Energy Agency (IAEA). This exhaustive collection of experimental data, graphs, programs and comparisons, is the legacy of Helmut Paul, who made it accessible to the global scientific community, and has been extensively employed in theoretical and experimental research during the last 25 years. The field of stopping power in matter is evolving, with new trends in materials of interest, including oxides, nitrides, polymers, and biological targets. Our goal is to identify areas of interest and emerging data needs to meet the requirements of a continuously developing user community.

  8. Stopping, goal-conflict, trait anxiety and frontal rhythmic power in the stop-signal task.

    Science.gov (United States)

    Neo, Phoebe S-H; Thurlow, Jane K; McNaughton, Neil

    2011-12-01

    The medial right frontal cortex is implicated in fast stopping of an initiated motor action in the stop-signal task (SST). To assess whether this region is also involved in the slower behavioural inhibition induced by goal conflict, we tested for effects of goal conflict (when stop and go tendencies are balanced) on low-frequency rhythms in the SST. Stop trials were divided, according to the delays at which the stop signal occurred, into short-, intermediate-, and long-delay trials. Consistent with goal-conflict processing, intermediate-delay trials were associated with greater 7-8 Hz EEG power than short- or long-delay trials at medial right frontal sites (Fz, F4, and F8). At F8, 7-8 Hz power was linked to high trait anxiety and neuroticism. A separate 4-7 Hz power increase was also seen in stop, relative to go, trials, but this was independent of delay, was maximal at the central midline site Cz, and predicted faster stopping. Together with previous data on the SST, these results suggest that the right frontal region could be involved in multiple inhibition mechanisms. We propose a hierarchical model of the control of stopping that integrates the literature on the neural control of fast motor stopping with that on slower, motive-directed behavioural inhibition.

  9. Note on measuring electronic stopping of slow ions

    Science.gov (United States)

    Sigmund, P.; Schinner, A.

    2017-11-01

    Extracting stopping cross sections from energy-loss measurements requires careful consideration of the experimental geometry. Standard procedures for separating nuclear from electronic stopping treat electronic energy loss as a friction force, ignoring its dependence on impact parameter. In the present study we find that incorporating this dependence has a major effect on measured stopping cross sections, in particular for light ions at low beam energies. Calculations have been made for transmission geometry, nuclear interactions being quantified by Bohr-Williams theory of multiple scattering on the basis of a Thomas-Fermi-Molière potential, whereas electronic interactions are characterized by Firsov theory or PASS code. Differences between the full and the restricted stopping cross section depend on target thickness and opening angle of the detector and need to be taken into account in comparisons with theory as well as in applications of stopping data. It follows that the reciprocity principle can be violated when checked on restricted instead of full electronic stopping cross sections. Finally, we assert that a seeming gas-solid difference in stopping of low-energy ions is actually a metal-insulator difference. In comparisons with experimental results we mostly consider proton data, where nuclear stopping is only a minor perturbation.

  10. Stopping power. Projectile and target modeled as oscillators

    International Nuclear Information System (INIS)

    Stevanovic, N.; Nikezic, D.

    2005-01-01

    In this Letter the collision of two quantum harmonic oscillators was considered. The oscillators interact through the Coulomb interaction. Stopping power of projectile was calculated assuming that both, target and projectile may be excited. It has been shown that the frequency of the projectile oscillation, ω p influences on stopping power, particularly in the region of Bragg peak. If, ω p ->0 is substitute in the expression for stopping power derived in this Letter, then it comes to the form when the projectile has been treated as point like charged particle

  11. Use of a range scaling method to determine alanine/water stopping power ratios

    International Nuclear Information System (INIS)

    McEwen, M.R.; Sephton, J.P.; Sharpe, P.H.G.; Shipley, D.R.

    2003-01-01

    A phantom composed of alanine dosimeter material has been constructed and depth-dose measurements made in a 10 MeV electron beam. The results have demonstrated the feasibility of using relative depth-dose measurements to determine stopping power ratios in materials of dosimetric interest. Experimental stopping power ratios for alanine dosimeter material and water agreed with the data of ICRU Report 37 within the uncertainty of the experiment (±1.2% at a 95% confidence level)

  12. Nuclear stopping power at high energies

    International Nuclear Information System (INIS)

    Date, S.; Gyulassy, M.; Sumiyoshi, H.

    1985-03-01

    Recent p + A → p + X data are analyzed within the context of the multi-chain and additive quark models. We deduce the average energy loss of a baryon as a function of distance traversed in nuclear matter. Consistency of the multi-chain model is checked by comparing the predictions for p + A → π +- + X with data. We discuss the space-time development of baryon stopping and show how longitudinal growth limits the energy deposition per unit length. Predictions are made for the proton spectra to be measured in nucleus-nucleus collisions at CERN and BNL. Finally, we conclude that the stopping domain for central collisions of heavy ions extends up to center of mass kinetic energies KEsub(em) asymptotically equals 3 +- 1 AGev. (author)

  13. Electronic stopping in ion-fullerene collisions

    NARCIS (Netherlands)

    Schlathölter, T.A.; Hadjar, O.; Hoekstra, R.A.; Morgenstern, R.W.H.

    The electronic friction experienced by a multiply charged ion interacting with the valence electrons of a single fullerene is an important aspect of the collision dynamics. It manifests itself in a considerable loss of projectile kinetic energy transferred to the target, resulting in excitation. The

  14. ELectron stopping of heavy ions in a matter

    International Nuclear Information System (INIS)

    Akhiezer, I.A.; Davydov, L.N.

    1978-01-01

    The theory of heavy ion stopping by electrons in solids is analyzed with an aim to establish which physical mechanisms are of importance at different ion velocity values v. The theory is presented for deep inelastic collisions taking the main part in stopping at v > Zsub(1)sup(1/3) v 0 (z 1 is the atomic number of the ion, v 0 is the Bohr velocity). Elastic scattering (relative to the incident ion) are investigated. It is shown that the contribution from these processes to the stopping cross-section is predominant at Zsub(1)sup(1/3) v 0 > v > Zsub(1)sup(2/3) v 0

  15. Power Electronics

    Indian Academy of Sciences (India)

    They cover a wide spectrum of areas from power supplies to power system ... Ramanarayanan describe the modelling and design of a family of soft transition ... of power when the drive is operating in the braking mode and fast dynamic response. ... time models are extremely important, as they can be included in real time ...

  16. Power Electronics

    Indian Academy of Sciences (India)

    Such real time models are extremely important, as they can be included in real time simulation of sys- tems to evolve control schemes for the converters as well as to study the effect on the power system. In view of the control possibilities offered by the use of power converters and the newly emerging applications, there has ...

  17. Simulation on effect of stopping nuclear power generation

    International Nuclear Information System (INIS)

    Yajima, Masayuki; Kumakura, Osamu; Sakurai, Norihisa; Nagata, Yutaka; Hattori, Tsuneaki

    1990-01-01

    The effects that the stopping of nuclear power generation exerts on the price of primary energy such as petroleum, LNG and coal and the trend of Japanese energy and economy are analyzed by using the medium term economy forecasting system. In the simulation, the case of stopping nuclear power generation in seven countries of OECD is supposed, and as for the process of stopping, two cases of immediate stopping and stopping by gradual reduction are set up. The models used for the simulation are the world energy model, the competition among energies model and the multiple category model. By the decrease of nuclear power generation, thermal power generation increases, and the demand of fossil fuel increases. As the result, the price of fossil fuel rises (the world energy model), and the price of fossil fuel imported to Japan rises. Also the quantity of fossil fuel import to Japan increase. These price rise and quantity increase exert deflation effect to Japanese economy (the multiple category model). The price rise of fossil fuel affects the competition among energies in Japan through the relative change of secondary energy price (the competition among energies model). The impact to the world and to Japan is discussed. (K.I.)

  18. Impact-parameter-dependent electronic stopping of swift ions

    NARCIS (Netherlands)

    Schinner, A.; Sigmund, P.

    2010-01-01

    A computational scheme has been developed to estimate the mean electronic energy loss of an incident swift ion on an atomic target as a function of the impact parameter between the moving nuclei. The theoretical basis is binary stopping theory. In order to extract impact-parameter dependencies it

  19. Reciprocity in the electronic stopping of slow ions in matter

    International Nuclear Information System (INIS)

    Sigmund, P.

    2008-01-01

    The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ∼10%) for many systems studied, and deviations exceeding ∼20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z 1 with Z 2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high. (authors)

  20. Reciprocity in the electronic stopping of slow ions in matter

    Science.gov (United States)

    Sigmund, P.

    2008-04-01

    The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ~10%) for many systems studied, and deviations exceeding ~20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z1 with Z2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high.

  1. Interaction of low-energy electrons and positrons with condensed matter: Stopping powers and inelastic mean free paths from optical data

    International Nuclear Information System (INIS)

    Ashley, J.C.

    1989-01-01

    An ''optical-data model'' is described for evaluating energy loss per unit pathlength and inelastic mean free path for low-energy electrons and positrons (approx lt 10 keV) from optical data on the medium of interest. Exchange between the incident electron and electrons in the medium is included. Results from the optical-data model are compared with previous theoretical calculations. 15 refs., 6 figs., 2 tabs

  2. New developments in stopping power for fast ions

    International Nuclear Information System (INIS)

    Paul, Helmut

    2007-01-01

    We discuss the available stopping power tables and codes, and new experimental methods. Among the semi-empirical stopping power tables, SRIM and MSTAR describe experimental data best. Of the recent theoretical stopping codes CasP, PASS, TCS and dielectric formalism, all describe some data well. PASS is the only theoretical code with an extended table for many ions and targets, but on the average, its predictive value at low energies is less than that of SRIM or MSTAR. The first-principle extended classical trajectory Monte Carlo method is very promising. The ToF-E ERDA arrangements have made it possible to produce accurate data for many ion-target combinations. A new liquid jet target method promises data for liquid water which is an important substance for medical dosimetry

  3. Theoretical model for calculation of molecular stopping power

    International Nuclear Information System (INIS)

    Xu, Y.J.

    1984-01-01

    A modified local plasma model based on the work of Linhard-Winther, Bethe, Brown, and Walske is established. The Gordon-Kim's molecular charged density model is employed to obtain a formula to evaluate the stopping power of many useful molecular systems. The stopping power of H 2 and He gas was calculated for incident proton energy ranging from 100 KeV to 2.5 MeV. The stopping power of O 2 , N 2 , and water vapor was also calculated for incident proton energy ranging from 40 keV to 2.5 MeV. Good agreement with experimental data was obtained. A discussion of molecular effects leading to departure from Bragg's rule is presented. The equipartition rule and the effect of nuclear momentum recoiling in stopping power are also discussed in the appendix. The calculation procedure presented hopefully can easily be extended to include the most useful organic systems such as the molecules composed of carbon, nitrogen, hydrogen and oxygen which are useful in radiation protection field

  4. Stopping power of antiprotons in H, H2, and He targets

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    The stopping power of antiprotons in atomic and molecular hydrogen as well as helium was calculated in an impact-energy range from 1 keV to 6.4 MeV. In the case of H2 and He the targets were described with a single-active electron model centered on the target. The collision process was treated...... of the corrections to the first-order stopping number, the average energy transferred to the target electrons, and the relative importance of the excitation and the ionization process for the energy loss of the projectile was determined. Finally, the stopping powers of the H, H2, and He targets were directly...

  5. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons; Desenvolvimento de uma metodologia para estimativa da dose absorvida e do poder de freamento para eletrons de conversao de baixa energia

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internalcontamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy {sup 109} Cd conversion electrons, working with a 4 {pi} proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin {sup 109} Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  6. Monte Carlo based water/medium stopping-power ratios for various ICRP and ICRU tissues

    International Nuclear Information System (INIS)

    Fernandez-Varea, Jose M; Carrasco, Pablo; Panettieri, Vanessa; Brualla, Lorenzo

    2007-01-01

    Water/medium stopping-power ratios, s w,m , have been calculated for several ICRP and ICRU tissues, namely adipose tissue, brain, cortical bone, liver, lung (deflated and inflated) and spongiosa. The considered clinical beams were 6 and 18 MV x-rays and the field size was 10 x 10 cm 2 . Fluence distributions were scored at a depth of 10 cm using the Monte Carlo code PENELOPE. The collision stopping powers for the studied tissues were evaluated employing the formalism of ICRU Report 37 (1984 Stopping Powers for Electrons and Positrons (Bethesda, MD: ICRU)). The Bragg-Gray values of s w,m calculated with these ingredients range from about 0.98 (adipose tissue) to nearly 1.14 (cortical bone), displaying a rather small variation with beam quality. Excellent agreement, to within 0.1%, is found with stopping-power ratios reported by Siebers et al (2000a Phys. Med. Biol. 45 983-95) for cortical bone, inflated lung and spongiosa. In the case of cortical bone, s w,m changes approximately 2% when either ICRP or ICRU compositions are adopted, whereas the stopping-power ratios of lung, brain and adipose tissue are less sensitive to the selected composition. The mass density of lung also influences the calculated values of s w,m , reducing them by around 1% (6 MV) and 2% (18 MV) when going from deflated to inflated lung

  7. Reasons for Starting and Stopping Electronic Cigarette Use

    Directory of Open Access Journals (Sweden)

    Jessica K. Pepper

    2014-10-01

    Full Text Available The aim of our study was to explore reasons for starting and then stopping electronic cigarette (e-cigarette use. Among a national sample of 3878 U.S. adults who reported ever trying e-cigarettes, the most common reasons for trying were curiosity (53%; because a friend or family member used, gave, or offered e-cigarettes (34%; and quitting or reducing smoking (30%. Nearly two-thirds (65% of people who started using e-cigarettes later stopped using them. Discontinuation was more common among those whose main reason for trying was not goal-oriented (e.g., curiosity than goal-oriented (e.g., quitting smoking (81% vs. 45%, p < 0.001. The most common reasons for stopping e-cigarette use were that respondents were just experimenting (49%, using e-cigarettes did not feel like smoking cigarettes (15%, and users did not like the taste (14%. Our results suggest there are two categories of e-cigarette users: those who try for goal-oriented reasons and typically continue using and those who try for non-goal-oriented reasons and then typically stop using. Research should distinguish e-cigarette experimenters from motivated users whose decisions to discontinue relate to the utility or experience of use. Depending on whether e-cigarettes prove to be effective smoking cessation tools or whether they deter cessation, public health programs may need distinct strategies to reach and influence different types of users.

  8. Reasons for starting and stopping electronic cigarette use.

    Science.gov (United States)

    Pepper, Jessica K; Ribisl, Kurt M; Emery, Sherry L; Brewer, Noel T

    2014-10-03

    The aim of our study was to explore reasons for starting and then stopping electronic cigarette (e-cigarette) use. Among a national sample of 3878 U.S. adults who reported ever trying e-cigarettes, the most common reasons for trying were curiosity (53%); because a friend or family member used, gave, or offered e-cigarettes (34%); and quitting or reducing smoking (30%). Nearly two-thirds (65%) of people who started using e-cigarettes later stopped using them. Discontinuation was more common among those whose main reason for trying was not goal-oriented (e.g., curiosity) than goal-oriented (e.g., quitting smoking) (81% vs. 45%, p reasons for stopping e-cigarette use were that respondents were just experimenting (49%), using e-cigarettes did not feel like smoking cigarettes (15%), and users did not like the taste (14%). Our results suggest there are two categories of e-cigarette users: those who try for goal-oriented reasons and typically continue using and those who try for non-goal-oriented reasons and then typically stop using. Research should distinguish e-cigarette experimenters from motivated users whose decisions to discontinue relate to the utility or experience of use. Depending on whether e-cigarettes prove to be effective smoking cessation tools or whether they deter cessation, public health programs may need distinct strategies to reach and influence different types of users.

  9. Stopping power for heavy ions in gases: a comparative study

    International Nuclear Information System (INIS)

    Diwan, P.K.; Singh, Lakhwant; Singh, Gurinder; Shyam Kumar

    1999-01-01

    The accurate knowledge of stopping power for heavy ions in gases is of paramount importance in nuclear reaction studies for the identification of reaction products involving ΔE-E telescope detectors. In the present work, it has been calculated the stopping power values for different heavy ions, such as Ne, Ar, Cu, Kr and Ag in various gas absorbers like H 2 , He, N 2 , Ne, Ar, Kr and Xe in the energy domain ∼ 2.5-6 MeV/n using the SRIM-98 code recently developed by Ziegler and the formulations of Benton and Henke, Hubert et al, Mukherjee and Nayak and Northcliffe and Schilling. This study has been undertaken in order to establish the validity of various semiempirical formulations for gas targets

  10. Simultaneous wide-range stopping power determination for several ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Trzaska, W.H.; Lyapin, V.; Raeisaenen, J.; Tiourine, G.; Virtanen, A

    2002-05-01

    A new procedure to extract simultaneously continuous stopping power curves for several ions and several absorbers over a wide energy range and with statistical errors reduced to negligible level is presented. The method combines our novel time-of-flight based method with the capability of our K130 cyclotron and ECR ion-source to produce the so-called ion cocktails. The potential of the method is demonstrated with a 6.0 MeV/u cocktail consisting of {sup 16}O{sup 4+}, {sup 28}Si{sup 7+} and {sup 40}Ar{sup 10+} ions. The stopping power in polycarbonate in the energy range of 0.35-5 MeV/u has been determined with absolute uncertainty of less than 2.3% and with relative below 0.2%. The results are compared with literature data and with SRIM2000 parameterisation including cores and bonds corrections.

  11. Potential information and stopping power from channeling in diamond

    International Nuclear Information System (INIS)

    Edge, R.D.; Derry, J.E.; Fearick, R.W.; Sellschop, J.P.F.

    1983-01-01

    When a carefully cleaned diamond crystal was bombarded with helium nuclei parallel to a low index plane, up to seven peaks in the energy spectrum of backscattered ions were seen. These arose from particles oscillating to and fro across the channel as they progressed along it. Spectra taken with ions incident in different directions in the same plane allowed both the wavelengths of the oscillations in the channel, lambda, and the stopping power within the channel to be obtained. The character of the oscillations changed as the beam deviated from exact alignment with the channel, giving the highest maximum at an angle /psi/ /SUB m/ to the channel. Calculations based on those of Barrett employing lambda, /psi/ /SUB m/, and the stopping power showed a smoother potential for the (111) planar channel, which has a larger spacing, than (100) and (110). The energy dependence of the stopping power and oscillation wavelength was also determined from 0.2 to 1.2 MeV for the (110) planar channel

  12. The gaseous emission of polymers under swift heavy ion irradiation: effect of the electronic stopping power; L'emission gazeuse des polymeres aliphatiques sous irradiation: effet du pouvoir d'arret electronique

    Energy Technology Data Exchange (ETDEWEB)

    Picq, V

    2000-07-01

    This thesis contributes to a better understanding of the damaging processes, which occur in polymers under swift heavy ion irradiation. The present study is exclusively devoted to the influence of the electronic stopping power, (dE/dx)e, on the molecular emission under irradiation. The irradiated polymers are polyethylene, polypropylene and poly-butene. The (dE/dx)e of the projectiles used varies from 3.5*10{sup -3} MeV.mg{sup -1}.cm{sup 2} (electron) to 39 MeV.mg{sup -1}.cm{sup 2} ({sup 58}Ni). We used two different experimental approaches in order to identify the nature of the emitted gases: mass spectrometry and infrared spectroscopy. The first technique is non selective, therefore, we could detect the emission of H{sub 2} and heavy molecules; it also gives information on the diffusion kinetics of the molecules formed. The use of infrared spectroscopy for this kind of analysis is new and the technique was developed at the laboratory. It enables us to identify, without any ambiguity, molecules with up to three carbon atoms. The experimental spectra are analysed by using reference spectra of pure gases, measured in our laboratory. We have quantified precisely each identified gas, and we have followed the evolution of the radiochemical yields with increasing (dE/dx)e. The results, obtained at different (dE/dx)e, inform us on the different mechanisms of gas molecules formation, for example the side group departure and, at high (dE/dx)e, the fragmentation of the main chain which is due to multiple ionisation of the macromolecule. (author)

  13. Stopping Power and Energy Straggling of Channeled He-Ions in GaN

    International Nuclear Information System (INIS)

    Turos, A.; Ratajczak, R.; Pagowska, K.; Nowicki, L.; Stonert, A.; Caban, P.

    2011-01-01

    GaN epitaxial layers are usually grown on sapphire substrates. To avoid disastrous effect of the large lattice mismatch a thin polycrystalline nucleation layer is grown at 500 o C followed by the deposition of thick GaN template at much higher temperature. Remnants of the nucleation layer were visualized by transmission electron microscopy as defect agglomeration at the GaN/sapphire interface and provide a very useful depth marker for the measurement of channeled ions stopping power. Random and aligned spectra of He ions incident at energies ranging from 1.7 to 3.7 MeV have been measured and evaluated using the Monte Carlo simulation code McChasy. Impact parameter dependent stopping power has been calculated for channeling direction and its parameters have been adjusted according to experimental data. For virgin, i.e. as grown, samples, the ratio of channeled to random stopping power is constant and amounts to 0.7 in the energy range studied. Defects produced by ion implantation largely influence the stopping power. For channeled ions the variety of possible trajectories leads to different energy loss at a given depth, thus resulting in much larger energy straggling than that for the random path. Beam energy distributions at different depths have been calculated using the McChasy code. They are significantly broader than those predicted by the Bohr formula for random direction. (author)

  14. Ab initio research of stopping power for energetic ions in solids

    Energy Technology Data Exchange (ETDEWEB)

    He, Bin, E-mail: hebin-rc@163.com; Meng, Xu-Jun; Wang, Jian-Guo

    2017-03-01

    A new physical scenario is suggested to estimate the stopping power of energetic α particles in solid-density Be, Na, and Al at room temperature in an ab initio way based on the average atom model. In the scenario the stopping power is caused by the transition of free electrons to higher energy states and the ionization of bound electrons of the atom. Our results are found generally in good agreement with the recommended data in Al, Be and Na as well as the experimental data in Al. A comparison of energy loss with the recent experiment of protons in Be indicates that the scenario is more reasonable than the local density approximation in this case.

  15. Improvements in the stopping power library libdEdx and release of the web GUI dedx.au.dk

    International Nuclear Information System (INIS)

    Toftegaard, J; Lühr, A; Bassler, N; Sobolevsky, N

    2014-01-01

    Purpose: In ion beam therapy electronic stopping power data enter in different disciplines, e.g., dose planning, dosimetry, and radiobiology. However, relevant stopping power data are only known within an accuracy of 2%-10%. We started the software library project libdEdx to unify data from several well-known stopping power sources into one ready-to-use package being 1) freely available and 2) easy accessible via a web-based front end. Methods: Currently, stopping power data from PSTAR, ASTAR, MSTAR and ICRU49+73 are implemented along with a version of the Bethe formula. The library is programmed in the language C to provide broad portability and high performance. A clean API provides full access to the underlying functions and thread safety in multi-threaded applications. The possibility to define arbitrary materials complements the list of predefined ICRU materials. Furthermore, we introduced a collection of tools, e.g., inverse stopping power look-up as well as CSDA range calculation and its inverse. Results: On a standard desktop PC libdEdx calculates 22 million look-ups/sec. A web GUI (available at http://dedx.au.dk) provides easy access to libdEdx and download of stopping data and graphs. For compounds, we observe that stopping power data are robust for variations in the mean excitation potential of the constituents as long as the total mean excitation potential is fixated. Conclusion: We released libdEdx (version number 1.2.1: http://sf.net/projects/libdedx/) with a web-based GUI. Future development will focus on implementing further stopping powers sources (e.g., for electrons and nuclear stopping) and relativistic effects.

  16. Power Electronics for Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Blaabjerg, Frede

    2016-01-01

    A microgrid (MG) is a stand-alone or grid-connected hybrid renewable system that uses distributed renewable and nonrenewable energy sources and energy storage systems (ESSs) to supply power to local loads. The system is ordinarily based on power electronics, with interface converters allowing...... a continuous supply of power in the presence of variable RES production. This chapter describes some specific features of DC MGs in terms of power architecture, control, and protection. It also reviews several uncommon power electronic interfaces. Regarding control, operation without critical communication...... are explained in this chapter. The chapter concludes with a review of power electronic intensive protection solutions for DC MGs....

  17. Stopping power for particle therapy: the generic library libdEdx and clinically relevant stopping-power ratios for light ions

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Toftegaard, Jakob; Kantemiris, Ioannis

    2012-01-01

    to be known accurately for dosimetry. Methods: An open-source computer library called libdEdx (library for energy loss per unit path length, dE/dx, calculations) is developed, providing stopping-power data from data tables and computer programs as well as a stopping-power formula comprising a large list...

  18. Improved atomic data for electron-transport predictions by the codes TIGER and TIGERP: II. Electron stopping and range data

    International Nuclear Information System (INIS)

    Peek, J.M.; Halbleib, J.A.

    1983-04-01

    The electron stopping and range data now used in the TIGER and TIGERP electron-transport codes are extracted and compared with other data for these processes. At the smallest collision energies treated by these codes, E approx. 1 keV, the stopping-power is estimated to be accurate for small-Z targets, to be about 25 percent too small for Z near 36 and to be a factor of three too small for Z > 79. These errors decrease with increasing E and the largest error for any target is roughly 20 percent for E = 10 keV. The closely related continuous-slowing-down range is estimated, at 1 keV, to be about 25 percent too small for small-Z targets and a factor of 2 too large for large-Z targets. The electron-transport problem of reflection from planer surfaces is re-investigated with improved stopping-power data. The effects of this change for the examples considered were about the size of the statistical uncertainties in the calculation, 1 to 2 percent

  19. Ab initio approach to the ion stopping power at the plasma-solid interface

    Science.gov (United States)

    Bonitz, Michael; Schlünzen, Niclas; Wulff, Lasse; Joost, Jan-Philip; Balzer, Karsten

    2016-10-01

    The energy loss of ions in solids is of key relevance for many applications of plasmas, ranging from plasma technology to fusion. Standard approaches are based on density functional theory or SRIM simulations, however, the applicability range and accuracy of these results are difficult to assess, in particular, for low energies. Here we present an independent approach that is based on ab initio nonequilibrium Green functions theory, e.g. that allows to incorporate electronic correlations effects of the solid. We present the first application of this method to low-temperature plasmas, concentrating on proton and alpha-particle stopping in a graphene layer. In addition to the stopping power we present time-dependent results for the local electron density, the spectral function and the photoemission spectrum that is directly accessible in optical, UV or x-ray diagnostics. http://www.itap.uni-kiel.de/theo-physik/bonitz/.

  20. Basic experimental preparation for the measurement of the stopping power of heavy ions in matter

    International Nuclear Information System (INIS)

    Carvalho Brito Brum, H. de.

    1976-02-01

    To measure the stopping power of heavy ions in solid matter one must develop both an experimental apparatus and a data analysis program. This thesis discusses these preparatory works and the methods to be employed. The design, building and testing of a scattering chamber with many detectors; the preparation of thin solid films, their analysis by electron diffraction and their thickness measurements; the testing of the electronic system; the calibration of the 4 MeV Van de Graaf accelerator at PUC/RJ; and the development of an original data analysis computer program are presented. (Author) [pt

  1. Materials specificity, quantum length scales, and stopping powers

    International Nuclear Information System (INIS)

    Trickey, S.B.; Wu, Jin Z.; Sabin, John R.

    1994-01-01

    Standard arguments, based primarily on behavior at high projectile energies and classical notions of thickness as a continuous parameter, assert that stopping powers are only modestly affected by target chemistry and aggregation and by sample thickness if the thickness is ''sufficiently small'' (and channeling is avoided). Sufficient thinness usually is defined in terms of freedom from multiple scattering and from projectile charge-state changes. The growing technological importance of extremely thin material layers (e.g. microelectronics) has motivated re-examination of both the thickness and aggregation-state assertions. We give arguments to show that both are inadequate and reappraise recent computations in confirmation. A particular focus is the proper definition of thickness for an ultrathin film of ν atomic planes (ν=1, 2, 3,.s). ((orig.))

  2. Ion energy loss at maximum stopping power in a laser-generated plasma

    International Nuclear Information System (INIS)

    Cayzac, W.

    2013-01-01

    In the frame of this thesis, a new experimental setup for the measurement of the energy loss of carbon ions at maximum stopping power in a hot laser-generated plasma has been developed and successfully tested. In this parameter range where the projectile velocity is of the same order of magnitude as the thermal velocity of the plasma free electrons, large uncertainties of up to 50% are present in the stopping-power description. To date, no experimental data are available to perform a theory benchmarking. Testing the different stopping theories is yet essential for inertial confinement fusion and in particular for the understanding of the alpha-particle heating of the thermonuclear fuel. Here, for the first time, precise measurements were carried out in a reproducible and entirely characterized beam-plasma configuration. It involved a nearly fully-stripped ion beam probing a homogeneous fully-ionized plasma. This plasma was generated by irradiating a thin carbon foil with two high-energy laser beams and features a maximum electron temperature of 200 eV. The plasma conditions were simulated with a two-dimensional radiative hydrodynamic code, while the ion-beam charge-state distribution was predicted by means of a Monte-Carlo code describing the charge-exchange processes of projectile ions in plasma. To probe at maximum stopping power, high-frequency pulsed ion bunches were decelerated to an energy of 0.5 MeV per nucleon. The ion energy loss was determined by a time-of-flight measurement using a specifically developed chemical-vapor-deposition diamond detector that was screened against any plasma radiation. A first experimental campaign was carried out using this newly developed platform, in which a precision better than 200 keV on the energy loss was reached. This allowed, via the knowledge of the plasma and of the beam parameters, to reliably test several stopping theories, either based on perturbation theory or on a nonlinear T-Matrix formalism. A preliminary

  3. Stopping powers and ranges for the heaviest atoms

    International Nuclear Information System (INIS)

    Sagaidak, Roman N.; Utyonkov, Vladimir K.; Dmitriev, Sergey N.

    2015-01-01

    Slowing down and stopping of the heaviest atoms, products of the fusion–evaporation nuclear reactions, during their passage through the Dubna gas-filled recoil separator has been studied using TRIM simulations. The study is important for experiments on the synthesis of super-heavy elements (SHEs) with atomic numbers around Z_P = 114 produced with accelerated heavy ion (HI) beams and extracted with a separator for their detection. The average Mylar stopping power (SP) values obtained with the simulations for HIs with 82 ⩽ Z_P ⩽ 92 reveal almost the same magnitudes, allowing extrapolation to the region of Z_P > 92. Similar extrapolation of the ranges in an He + Ar gas mixture leads to rather small values for the heaviest atoms (Z_P ⩾ 102) as compared to the range for U. The extrapolated values have large uncertainties and should be verified with different approaches. Available SP data obtained for HIs with 18 ⩽ Z_P ⩽ 92 at energies E < 20 MeV/u have been analysed within various semi-empirical approaches. The analysis has shown that existing parameterizations give Mylar SP values for Z_P ⩾ 82 that are very different from each other at energies of interest (around 0.1 MeV/u). We propose to use a general approach based on the HI effective charge parameterization obtained with available SP data for HIs and the hydrogen SP and effective charge corresponding to the same velocity and stopping medium as those for HIs. In this manner, the SPs of the gases H_2, He, C_4H_1_0, and Ar as well as those of the solids Mylar, C, Al, and Ti have been obtained for any atoms with Z_P ⩾ 18 (including the heaviest ones) at their reduced velocities 0.03 ⩽ V_r_e_d ⩽ 5.0. The SP values derived in such a way seem to be more reliable compared to the existing semi-empirical calculations and can be used in the conditioning of experiments on the synthesis of SHEs.

  4. Subshell stopping power of the elements for protons in the Born approximation

    International Nuclear Information System (INIS)

    McGuire, E.J.

    1982-01-01

    The generalized oscillator-strength formulation of the Born approximation was used to generate a large sample of subshell excitation and ionization generalized oscillator strengths across the periodic table. These were used to calculate the excitation and ionization contributions to the proton stopping power by individual subshells. The subshell ionization stopping powers are expressed in scaled form, depending on the subshell ionization energy. Detailed comparison of the calculated total proton stopping power is in good agreement with experiment across the periodic table. Detailed calculations show the importance of outer-shell ionization and excitation to the total stopping power for protons with energy less than 10 MeV

  5. Resonant charging and stopping power of slow channelling atoms in a crystalline metal

    International Nuclear Information System (INIS)

    Mason, D R; Race, C P; Foo, M H F; Horsfield, A P; Foulkes, W M C; Sutton, A P

    2012-01-01

    Fast moving ions travel great distances along channels between low-index crystallographic planes, slowing through collisions with electrons, until finally they hit a host atom initiating a cascade of atomic displacements. Statistical penetration ranges of incident particles are reliably used in ion-implantation technologies, but a full, necessarily quantum-mechanical, description of the stopping of slow, heavy ions is challenging and the results of experimental investigations are not fully understood. Using a self-consistent model of the electronic structure of a metal, and explicit treatment of atomic structure, we find by direct simulation a resonant accumulation of charge on a channelling ion analogous to the Okorokov effect but originating in electronic excitation between delocalized and localized valence states on the channelling ion and its transient host neighbours, stimulated by the time-periodic potential experienced by the channelling ion. The charge resonance reduces the electronic stopping power on the channelling ion. These are surprising and interesting new chemical aspects of channelling, which cannot be predicted within the standard framework of ions travelling through homogeneous electron gases or by considering either ion or target in isolation. (paper)

  6. Quantum–classical simulations of the electronic stopping force and charge on slow heavy channelling ions in metals

    International Nuclear Information System (INIS)

    Race, C P; Mason, D R; Foo, M H F; Foulkes, W M C; Sutton, A P; Horsfield, A P

    2013-01-01

    By simulating the passage of heavy ions along open channels in a model crystalline metal using semi-classical Ehrenfest dynamics we directly investigate the nature of non-adiabatic electronic effects. Our time-dependent tight-binding approach incorporates both an explicit quantum mechanical electronic system and an explicit representation of a set of classical ions. The coupled evolution of the ions and electrons allows us to explore phenomena that lie beyond the approximations made in classical molecular dynamics simulations and in theories of electronic stopping. We report a velocity-dependent charge-localization phenomenon not predicted by previous theoretical treatments of channelling. This charge localization can be attributed to the excitation of electrons into defect states highly localized on the channelling ion. These modes of excitation only become active when the frequency at which the channelling ion moves from interstitial point to equivalent interstitial point matches the frequency corresponding to excitations from the Fermi level into the localized states. Examining the stopping force exerted on the channelling ion by the electronic system, we find broad agreement with theories of slow ion stopping (a stopping force proportional to velocity) for a low velocity channelling ion (up to about 0.5 nm fs −1 from our calculations), and a reduction in stopping power attributable to the charge localization effect at higher velocities. By exploiting the simplicity of our electronic structure model we are able to illuminate the physics behind the excitation processes that we observe and present an intuitive picture of electronic stopping from a real-space, chemical perspective. (paper)

  7. Reaction-in-flight neutrons as a test of stopping power in degenerate plasmas

    Science.gov (United States)

    Hayes, A. C.; Jungman, Gerard; Schulz, A. E.; Boswell, M.; Fowler, M. M.; Grim, G.; Klein, A.; Rundberg, R. S.; Wilhelmy, J. B.; Wilson, D.; Cerjan, C.; Schneider, D.; Sepke, S. M.; Tonchev, A.; Yeamans, C.

    2015-08-01

    We present the first measurements of reaction-in-flight (RIF) neutrons in an inertial confinement fusion system. The experiments were carried out at the National Ignition Facility, using both Low Foot and High Foot drives and cryogenic plastic capsules. In both cases, the high-energy RIF ( En> 15 MeV) component of the neutron spectrum was found to be about 10-4 of the total. The majority of the RIF neutrons were produced in the dense cold fuel surrounding the burning hotspot of the capsule, and the data are consistent with a compressed cold fuel that is moderately to strongly coupled (Γ˜ 0.6) and electron degenerate (θFermi/θe˜ 4). The production of RIF neutrons is controlled by the stopping power in the plasma. Thus, the current RIF measurements provide a unique test of stopping power models in an experimentally unexplored plasma regime. We find that the measured RIF data strongly constrain stopping models in warm dense plasma conditions, and some models are ruled out by our analysis of these experiments.

  8. Introduction to electrical power and power electronics

    CERN Document Server

    Patel, Mukund R

    2012-01-01

    Power Generation, Distribution, and Utilization AC Power Fundamentals Common Aspects of Power Equipments AC Generator AC and DC Motors Transformer Power Cable Power Distribution Fault Current Analysis System ProtectionEconomic Use of PowerElectrochemical BatteryPower Electronics and Motor Drives Power Electronics Devices DC-DC Converters AC-DC-AC Converters Variable-Frequency Drives Quality of Power Power Converter CoolingAppendixIndex

  9. High-power electronics

    CERN Document Server

    Kapitsa, Petr Leonidovich

    1966-01-01

    High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

  10. Comparison between static LFC and Mermin dielectric functions on proton stopping in a degenerate electron gas

    Energy Technology Data Exchange (ETDEWEB)

    Barriga-Carrasco, Manuel D. [E.T.S.I. Industriales, Universisdad de Castilla La Mancha, Ciudad Real E13071 (Spain)], E-mail: ManuelD.Barriga@uclm.es

    2009-07-11

    If plasmas are considered fully ionized, the electronic stopping of a charged particle that traverses them will only be due to free electrons. This stopping can be obtained in first view through random phase approximation (RPA). However, free electrons interact between them affecting the stopping. These interactions can be taken into account in the dielectric formalism in two different ways: the local field correction (LFC) and the Mermin dielectric functions. LFC produces an enhancement in stopping before the maximum and recovers the RPA values just after it. The Mermin method also produces first a high increase at very low energies, then a small enhancement at low energies and finally decreases below RPA values before and after the maximum. Differences between the two methods are very important at very low energies and 30% around the stopping maximum.

  11. Comparison between static LFC and Mermin dielectric functions on proton stopping in a degenerate electron gas

    International Nuclear Information System (INIS)

    Barriga-Carrasco, Manuel D.

    2009-01-01

    If plasmas are considered fully ionized, the electronic stopping of a charged particle that traverses them will only be due to free electrons. This stopping can be obtained in first view through random phase approximation (RPA). However, free electrons interact between them affecting the stopping. These interactions can be taken into account in the dielectric formalism in two different ways: the local field correction (LFC) and the Mermin dielectric functions. LFC produces an enhancement in stopping before the maximum and recovers the RPA values just after it. The Mermin method also produces first a high increase at very low energies, then a small enhancement at low energies and finally decreases below RPA values before and after the maximum. Differences between the two methods are very important at very low energies and 30% around the stopping maximum.

  12. Phasor power electronics

    CERN Document Server

    Rim, Chun T

    2016-01-01

    This book presents a comprehensive introduction to the principles of power electronics, focusing on the switched transformer concept and phasor transformation techniques as employed in the analysis and design of power electronic circuits. Phasor transformations, as introduced in this book, make the time-varying nature of a switching converter simple and easy to handle, transforming it into an equivalent time-invariant circuit. The book starts with an introduction to the philosophy and fundamental principles of power electronics. The switched transformer concept, which is applicable to any switching converter, is introduced, and it is shown how DC-DC converters analyses are then so straightforward that very little equational manipulation is needed. Then the phasor transformation techniques are comprehensively explained over three parts. Single phase and multi-phase AC systems are dealt with through the single phase phasor transformation and circuit DQ transformation, respectively. A general unified phasor tran...

  13. Study of the chemical binding effect on the molecular stopping power of V2O5

    International Nuclear Information System (INIS)

    Eisenbarth, S.R.

    1981-01-01

    The stopping powers of V and V 2 O 5 have been measured for helium ions with energies from 0.3 to 2.0 MeV and probable errors of 2.2 and 3.0%, respectively. The vanadium stopping power was 12 and 14% lower than the previous measurement of Chu and Powers (1969) and 2 to 5% lower than the semi-empirical values of Chu and Zeigler (1974) in this energy range. The V 2 O 5 stopping power was found to be 2 to 3.5% lower than the Bragg rule curve calculated with the molecular oxygen values of Bourland, Chu, and Powers (1971) and the present vanadium stopping power. The use of Bragg's rule to extract the oxygen contribution to the molecular stopping power of V 2 O 5 results in a solid oxygen stopping power which is in good agreement with the solid molecular oxygen measurement of Chu, Braun, Davies, Matsunami, and Thompson (1978) and approximately 5% higher than Feng's value (1974) obtained from metal oxides which have wide energy band gaps. The present experiment cautions against the use of a common stopping power for oxygen in Bragg rule calculations for solid compounds as purposed by Feng and by Zeigler and Chu (1976)

  14. Monte Carlo Simulations on the water-to-air stopping power ratio for carbon ion dosimetry

    DEFF Research Database (Denmark)

    Henkner, Katrin; Bassler, Niels; Sobolevsky, Nikolai

    2009-01-01

    Many papers discussed the I value for water given by the ICRU, concluding that a value of about 80±2  eV instead of 67.2  eV would reproduce measured ion depth-dose curves. A change in the I value for water would have an effect on the stopping power and, hence, on the water-to-air stopping power...... tables and ICRU reports. The stopping power ratio is calculated via track-length dose calculation with SHIELD-HIT07. In the calculations, the stopping power ratio is reduced to a value of 1.119 in the plateau region as compared to the cited value of 1.13 in IAEA TRS-398. At low energies the stopping...

  15. Power Electronics Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-07

    Thermal modeling was conducted to evaluate and develop thermal management strategies for high-temperature wide-bandgap (WBG)-based power electronics systems. WBG device temperatures of 175 degrees C to 250 degrees C were modeled under various under-hood temperature environments. Modeling result were used to identify the most effective capacitor cooling strategies under high device temperature conditions.

  16. Stopping Power of Solid Argon for Helium Ions

    DEFF Research Database (Denmark)

    Besenbacher, F.; Bøttiger, Jørgen; Grauersen, O.

    1981-01-01

    By means of the Rutherford-backscattering method, the stopping cross section of solid argon has been measured for 0.5–3 MeV helium ions to an accuracy of not, vert, similar3%. The results agree within the experimental accuracies with our earlier measurements for gaseous argon over the energy region...

  17. A note on extracting electronic stopping from energy spectra of backscattered slow ions applying Bragg's rule

    Science.gov (United States)

    Bruckner, B.; Roth, D.; Goebl, D.; Bauer, P.; Primetzhofer, D.

    2018-05-01

    Electronic stopping measurements in chemically reactive targets, e.g., transition and rare earth metals are challenging. These metals often contain low Z impurities, which contribute to electronic stopping. In this article, we present two ways how one can correct for the presence of impurities in the evaluation of proton and He stopping in Ni for primary energies between 1 and 100 keV, either considering or ignoring the contribution of the low Z impurities to multiple scattering. We find, that for protons either method leads to concordant results, but for heavier projectiles, e.g. He ions, the influence on multiple scattering must not be neglected.

  18. Developments regarding the Bragg rule for stopping power and critical examination of its application to water

    International Nuclear Information System (INIS)

    Kamaratos, E.

    1983-01-01

    A critical comparison is made of various experimental findings regarding the Bragg additivity rule for stopping power. It appears that deviations from the Bragg additivity rule reported a long time ago and ascribed to chemical binding effects and phase effects are real, despite even recent statements of the contrary. Nevertheless, when the Bragg rule is applied to water, critical examination of very recent experimental results for the stopping power in the gaseous state of water, hydrogen and oxygen in this work suggest that the reported deviations from the Bragg additivity rule for the stopping power of gaseous water may be the result of experimental error. (orig.)

  19. Stopping powers for protons in materials of interest in dosimetry and in medical and biological applications

    International Nuclear Information System (INIS)

    Thwaites, D.I.

    1985-01-01

    Stopping powers are required for many radiation applications in medicine and biology. Their accuracy can be critical. Some published calculations for these situations have not included recent developments in stopping power theory or the body of work on deviations from additivity due to phase of chemical binding effects. These areas have recently been reviewed and mean excitation energies recommended for a range of materials of interest. Calculated stopping powers are presented for protons of 0.4 to 200 MeV taking the available information into account. The materials considered are Lucite, ICRU composition muscle and bone, A-150 plastic, a TE gas, acetylene and polystyrene and water and water vapour. With suitable corrections and suitable I values in the Bethe stopping power expression, accuracies of <2% can be achieved. (author)

  20. Low-energy proton stopping power of N2, O2, and water vapor, and deviations from Bragg's rule

    International Nuclear Information System (INIS)

    Xu, Y.J.; Khandelwal, G.S.; Wilson, J.W.

    1984-01-01

    A modified local-plasma model, based on the works of Lindhard and Winther, and Bethe, Brown, and Walske is established. The Gordon-Kim model for molecular-electron density is used to calculate stopping power of N 2 , O 2 , and water vapor for protons of energy ranging from 40 keV to 2.5 MeV, resulting in good agreement with experimental data. Deviations from Bragg's rule are evaluated and are discussed under the present theoretical model

  1. Experimental verification of ion stopping power prediction from dual energy CT data in tissue surrogates

    Science.gov (United States)

    Farace, Paolo

    2014-11-01

    A two-steps procedure is presented to convert dual-energy CT data to stopping power ratio (SPR), relative to water. In the first step the relative electron density (RED) is calculated from dual-energy CT-numbers by means of a bi-linear relationship: RED = a HUscH + b HUscL + c, where HUscH and HUscL are scaled units (HUsc = HU + 1000) acquired at high and low energy respectively, and the three parameters a, b and c has to be determined for each CT scanner. In the second step the RED values were converted into SPR by means of published poly-line functions, which are invariant as they do not depend on a specific CT scanner. The comparison with other methods provides encouraging results, with residual SPR error on human tissue within 1%. The distinctive features of the proposed method are its simplicity and the generality of the conversion functions.

  2. Experimental verification of ion stopping power prediction from dual energy CT data in tissue surrogates.

    Science.gov (United States)

    Farace, Paolo

    2014-11-21

    A two-steps procedure is presented to convert dual-energy CT data to stopping power ratio (SPR), relative to water. In the first step the relative electron density (RED) is calculated from dual-energy CT-numbers by means of a bi-linear relationship: RED=a HUscH+b HUscL+c, where HUscH and HUscL are scaled units (HUsc=HU+1000) acquired at high and low energy respectively, and the three parameters a, b and c has to be determined for each CT scanner. In the second step the RED values were converted into SPR by means of published poly-line functions, which are invariant as they do not depend on a specific CT scanner. The comparison with other methods provides encouraging results, with residual SPR error on human tissue within 1%. The distinctive features of the proposed method are its simplicity and the generality of the conversion functions.

  3. Range and stopping power tables for 2.5-12MeV/nucleon heavy ions in solids

    International Nuclear Information System (INIS)

    Hubert, F.; Fleury, A.; Bimbot, R.; Gardes, D.

    1978-12-01

    A semi-empirical procedure to compute heavy ion stopping powers is presented. The calculations use recent stopping power values for alpha particles and a new parameterization for the effective charge taking into account the effect to the stopping medium. Stopping powers and ranges are tabulated for moving ions of atomic number 2<=Z<=45 in the energy region 2.5<=E/A<=12 MeV/nucleon for 18 solid materials

  4. Energy dependence of the stopping power of MeV 16O ions in a laser-produced plasma

    International Nuclear Information System (INIS)

    Sakumi, A.; Shibata, K.; Sato, R.; Tsubuku, K.; Nishimoto, T.; Hasegawa, J.; Ogawa, M.; Oguri, Y.; Katayama, T.

    2001-01-01

    The energy dependence of the stopping power of 16 O ions in a laser-produced plasma target was experimentally investigated in the projectile energy range of 150-350 keV/u. In order to produce the target plasma a Q-Switched Nd-glass laser was focused onto a small lithium hydride (LiH) pellet. The plasma electron temperature and the electron line density were 15 eV and 2x10 17 cm -2 , respectively. The energy loss of 16 O ions in the plasma was measured by a time-of-flight (TOF) method. We found that the stopping power in the plasma agreed with the theoretical estimation based on a modified Bohr equation with correction at low velocities. In this evaluation, the effective charge of the projectile was calculated by means of rate equations on the loss and capture of electrons. It has been also found that in this projectile energy range the stopping power of the 16 O ions in the plasma still increases with decreasing projectile energy, while it decreases in cold equivalent

  5. EMC in power electronics

    CERN Document Server

    Tihanyi, Laszlo

    1995-01-01

    Electronics professionals will find this book invaluable when designing power equipment, because it describes in detail how to cope with the problem of electromagnetic interference. The author shows how to meet the exacting US and European EMC standards for conducted emissions.The book includes a wide range of EMI analysis techniques. An important focus is on the energy content of interference transient signals (traditional analysis concentrates on amplitude and frequency). This provides a more accurate picture of the EMI situation. For those who do not want or need detailed analysis technique

  6. Review of stopping power and Coulomb explosion for molecular ion in plasmas

    Directory of Open Access Journals (Sweden)

    Guiqiu Wang

    2018-03-01

    Full Text Available We summarize our theoretical studies for stopping power of energetic heavy ion, diatomic molecular ions and small clusters penetrating through plasmas. As a relevant research field for the heavy ion inertial confinement fusion (HICF, we lay the emphasis on the dynamic polarization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma. On the other hand, as a promising scheme for ICF, both a strong laser field and an intense ion beam are used to irradiate a plasma target. So the influence of a strong laser field on stopping power is significant. We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C60 cluster. Furthermore, in order to indicate the effects of different cluster types and sizes on the stopping power, a comparison is made for hydrogen and carbon clusters. In addition, the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free. Finally, a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi'an Jiaotong University of China. Keywords: Molecules, Stopping power, Coulomb explosion, Vicinage effect, Laser, PACS Codes: 34.50.Bw, 52.40.Mj, 61.85.+p, 34.50.Dy

  7. Influence of H-C bonds on the stopping power of hard and soft carbonized layers

    International Nuclear Information System (INIS)

    Boutard, D.; Moeller, W.; Scherzer, B.M.U.

    1988-01-01

    Soft and hard carbon-hydrogen films were deposited in a rf glow discharge. Their stopping powers were deduced from depth-profile analysis by means of proton enhanced-cross-section scattering at around 1.5 MeV and 4 He + elastic-recoil detection at 2.6 MeV. In the case of soft films, ion-induced hydrogen depletion allowed study of the dependence of the stopping on hydrogen concentration. The presence of hydrogen increases the stopping power of the film by a factor of up to ∼2 compared to the predicted value for pure carbon. Moreover, Bragg's rule underestimates the total stopping considerably. However, good agreement is obtained with a recent theoretical model by Sabin et al. which takes into account the different C-C and C-H s

  8. Collisionless stopping of electron current in an inhomogeneous ...

    Indian Academy of Sciences (India)

    Ampere's law we can express b in terms of the typical incoming current filament dimension a and the electron velocity u. Thus b ∼ au. This shows that. Q ∼ KLb2aLzu ∼ (L/Ln)aLzu. (9). The energy dissipation depends on the same parameter ratio (Ln/L) which determined the criteria for trapping vs. transmission, noted ...

  9. Range-energy relations and stopping powers of organic liquids and vapours for alpha particles

    International Nuclear Information System (INIS)

    Akhavan-Rezayat, A.; Palmer, R.B.J.

    1980-01-01

    Experimental range-energy relations are presented for alpha particles in methyl alcohol, propyl alcohol, dichloromethane, chloroform and carbon tetrachloride in both the liquid and vapour phases. Stopping power values for these materials and for oxygen gas over the energy range 1.0-8.0 MeV are also given. From these results stopping powers have been derived for the -CH 2 -group and for -Cl occurring in chemical combination in the liquid and vapour phases. The molecular stopping power in the vapour phase is shown to exceed that in the liquid phase by 2-6% below 2 MeV, reducing to negligible differences at about 5 MeV for the materials directly investigated and for the -Cl atom. No significant phase effect is observed for the -CH 2 -group, but it is noted that the uncertainties in the values of the derived stopping powers are much greater in this case. Comparison of the experimental molecular stopping powers with values calculated from elemental values using the Bragg additivity rule shows agreement for vapours but not for liquids. (author)

  10. Power electronics reliability analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Mark A.; Atcitty, Stanley

    2009-12-01

    This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.

  11. Power electronics and motor drives

    CERN Document Server

    Wilamowski, Bogdan M

    2011-01-01

    Universities throughout the world typically provide an excellent education in the various aspects of electronics, however their focus is normally on traditional low power electronics. In contrast, in the industrial environment, there is a need for high power electronics that is used to control electromechanical systems in addition to the low power electronics typically employed for analog and digital systems. To address this need, Section 1 of this volume in The Industrial Electronics Handbook, Second Edition, is focused on special high power semiconductor devices. Section 2 not only describes

  12. A universal equation for the electronic stopping of ions in solids

    International Nuclear Information System (INIS)

    Montenegro, E.C.; Cruz, S.A.; Vargas-Aburto, C.

    1982-09-01

    An analytical equation for the electronic stopping of ions in solids for non-relativistic velocities, that has no adjustable parameters, is obtained in a semi-phenomenological manner. The very good agreement with experiment gives support to the physical arguments used in its derivation. (Author) [pt

  13. Direction-dependent stopping power and beam deflection in anisotropic solids

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1989-01-01

    Directional effects on the motion of swift ions in anisotropic media are studied. The stopping power is a function of the direction of the velocity relative to the principle axes of the medium, and there is a nonzero lateral force on the ion tending to bend its trajectory. These effects arise from the anisotropy of the dielectric response, and are distinct from channeling. Simple expressions are derived for the stopping power and lateral force in the nonrelativistic high-velocity limit, and calculations are performed for crystalline graphite. 6 refs., 7 figs

  14. Heavy-ion stopping powers and the low-velocity-projectile z3 effect

    International Nuclear Information System (INIS)

    Porter, L.E.

    1977-01-01

    Recent heavy-ion stopping-power measurements with elemental solid targets have been analyzed in order to ascertain the influence on effective ion charge of incorporating the low-velocity-projectile z 3 effect in Bethe-Bloch calculations. Shell corrections and the mean excitation energy of a given target were held fixed while searching for the best-fit value of a single charge-state parameter. In general, excellent fits to the stopping powers at projectile energies above 0.3 MeV/amu were achieved. Results of the present study compare very favorably with those from other extant methods of analysis

  15. A Review of Power Electronics for Wind Power

    DEFF Research Database (Denmark)

    Chen, Zhe

    2011-01-01

    The paper reviews the power electronic applications for wind energy systems. Main wind turbine systems with different generators and power electronic converters are described. The electrical topologies of wind farms with power electronic conversion are discussed. Power electronic applications...

  16. Measurement of the Muon Stopping Power in Lead Tungstate

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; Stahl, A; Tornier, D; Zoeller, M H; Aldaya Martin, M; Behrens, U; Borras, K; Campbell, A; Castro, E; Dammann, D; Eckerlin, G; Flossdorf, A; Flucke, G; Geiser, A; Hatton, D; Hauk, J; Jung, H; Kasemann, M; Katkov, I; Kleinwort, C; Kluge, H; Knutsson, A; Kuznetsova, E; Lange, W; Lohmann, W; Mankel, R; Marienfeld, M; Meyer, A B; Miglioranzi, S; Mnich, J; Ohlerich, M; Olzem, J; Parenti, A; Rosemann, C; Schmidt, R; Schoerner-Sadenius, T; Volyanskyy, D; Wissing, C; Zeuner, W D; Autermann, C; Bechtel, F; Draeger, J; Eckstein, D; Gebbert, U; Kaschube, K; Kaussen, G; Klanner, R; Mura, B; Naumann-Emme, S; Nowak, F; Pein, U; Sander, C; Schleper, P; Schum, T; Stadie, H; Steinbrück, G; Thomsen, J; Wolf, R; Bauer, J; Blüm, P; Buege, V; Cakir, A; Chwalek, T; De Boer, W; Dierlamm, A; Dirkes, G; Feindt, M; Felzmann, U; Frey, M; Furgeri, A; Gruschke, J; Hackstein, C; Hartmann, F; Heier, S; Heinrich, M; Held, H; Hirschbuehl, D; Hoffmann, K H; Honc, S; Jung, C; Kuhr, T; Liamsuwan, T; Martschei, D; Mueller, S; Müller, Th; Neuland, M B; Niegel, M; Oberst, O; Oehler, A; Ott, J; Peiffer, T; Piparo, D; Quast, G; Rabbertz, K; Ratnikov, F; Ratnikova, N; Renz, M; Saout, C; Sartisohn, G; Scheurer, A; Schieferdecker, P; Schilling, F P; Schott, G; Simonis, H J; Stober, F M; Sturm, P; Troendle, D; Trunov, A; Wagner, W; Wagner-Kuhr, J; Zeise, M; Zhukov, V; Ziebarth, E B; Daskalakis, G; Geralis, T; Karafasoulis, K; Kyriakis, A; Loukas, D; Markou, A; Markou, C; Mavrommatis, C; Petrakou, E; Zachariadou, A; Gouskos, L; Katsas, P; Panagiotou, A; Evangelou, I; Kokkas, P; Manthos, N; Papadopoulos, I; Patras, V; Triantis, F A; Bencze, G; Boldizsar, L; Debreczeni, G; Hajdu, C; Hernath, S; Hidas, P; Horvath, D; Krajczar, K; Laszlo, A; Patay, G; Sikler, F; Toth, N; Vesztergombi, G; Beni, N; Christian, G; Imrek, J; Molnar, J; Novak, D; Palinkas, J; Szekely, G; Szillasi, Z; Tokesi, K; Veszpremi, V; Kapusi, A; Marian, G; Raics, P; Szabo, Z; Trocsanyi, Z L; Ujvari, B; Zilizi, G; Bansal, S; Bawa, H S; Beri, S B; Bhatnagar, V; Jindal, M; Kaur, M; Kaur, R; Kohli, J M; Mehta, M Z; Nishu, N; Saini, L K; Sharma, A; Singh, A; Singh, J B; Singh, S P; Ahuja, S; Arora, S; Bhattacharya, S; Chauhan, S; Choudhary, B C; Gupta, P; Jain, S; Jha, M; Kumar, A; Ranjan, K; Shivpuri, R K; Srivastava, A K; Choudhury, R K; Dutta, D; Kailas, S; Kataria, S K; Mohanty, A K; Pant, L M; Shukla, P; Topkar, A; Aziz, T; Guchait, M; Gurtu, A; Maity, M; Majumder, D; Majumder, G; Mazumdar, K; Nayak, A; Saha, A; Sudhakar, K; Banerjee, S; Dugad, S; Mondal, N K; Arfaei, H; Bakhshiansohi, H; Fahim, A; Jafari, A; Mohammadi Najafabadi, M; Moshaii, A; Paktinat Mehdiabadi, S; Rouhani, S; Safarzadeh, B; Zeinali, M; Felcini, M; Abbrescia, M; Barbone, L; Chiumarulo, F; Clemente, A; Colaleo, A; Creanza, D; Cuscela, G; De Filippis, N; De Palma, M; De Robertis, G; Donvito, G; Fedele, F; Fiore, L; Franco, M; Iaselli, G; Lacalamita, N; Loddo, F; Lusito, L; Maggi, G; Maggi, M; Manna, N; Marangelli, B; My, S; Natali, S; Nuzzo, S; Papagni, G; Piccolomo, S; Pierro, G A; Pinto, C; Pompili, A; Pugliese, G; Rajan, R; Ranieri, A; Romano, F; Roselli, G; Selvaggi, G; Shinde, Y; Silvestris, L; Tupputi, S; Zito, G; Abbiendi, G; Bacchi, W; Benvenuti, A C; Boldini, M; Bonacorsi, D; Braibant-Giacomelli, S; Cafaro, V D; Caiazza, S S; Capiluppi, P; Castro, A; Cavallo, F R; Codispoti, G; Cuffiani, M; D'Antone, I; Dallavalle, G M; Fabbri, F; Fanfani, A; Fasanella, D; Giacomelli, P; Giordano, V; Giunta, M; Grandi, C; Guerzoni, M; Marcellini, S; Masetti, G; Montanari, A; Navarria, F L; Odorici, F; Pellegrini, G; Perrotta, A; Rossi, A M; Rovelli, T; Siroli, G; Torromeo, G; Travaglini, R; Albergo, S; Costa, S; Potenza, R; Tricomi, A; Tuve, C; Barbagli, G; Broccolo, G; Ciulli, V; Civinini, C; D'Alessandro, R; Focardi, E; Frosali, S; Gallo, E; Genta, C; Landi, G; Lenzi, P; Meschini, M; Paoletti, S; Sguazzoni, G; Tropiano, A; Benussi, L; Bertani, M; Bianco, S; Colafranceschi, S; Colonna, D; Fabbri, F; Giardoni, M; Passamonti, L; Piccolo, D; Pierluigi, D; Ponzio, B; Russo, A; Fabbricatore, P; Musenich, R; Benaglia, A; Calloni, M; Cerati, G B; D'Angelo, P; De Guio, F; Farina, F M; Ghezzi, A; Govoni, P; Malberti, M; Malvezzi, S; Martelli, A; Menasce, D; Miccio, V; Moroni, L; Negri, P; Paganoni, M; Pedrini, D; Pullia, A; Ragazzi, S; Redaelli, N; Sala, S; Salerno, R; Tabarelli de Fatis, T; Tancini, V; Taroni, S; Buontempo, S; Cavallo, N; Cimmino, A; De Gruttola, M; Fabozzi, F; Iorio, A O M; Lista, L; Lomidze, D; Noli, P; Paolucci, P; Sciacca, C; Azzi, P; Bacchetta, N; Barcellan, L; Bellan, P; Bellato, M; Benettoni, M; Biasotto, M; Bisello, D; Borsato, E; Branca, A; Carlin, R; Castellani, L; Checchia, P; Conti, E; Dal Corso, F; De Mattia, M; Dorigo, T; Dosselli, U; Fanzago, F; Gasparini, F; Gasparini, U; Giubilato, P; Gonella, F; Gresele, A; Gulmini, M; Kaminskiy, A; Lacaprara, S; Lazzizzera, I; Margoni, M; Maron, G; Mattiazzo, S; Mazzucato, M; Meneghelli, M; Meneguzzo, A T; Michelotto, M; Montecassiano, F; Nespolo, M; Passaseo, M; Pegoraro, M; Perrozzi, L; Pozzobon, N; Ronchese, P; 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D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in lead tungstate is measured to be 160+5/-6 plus or minus 8 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy.

  17. Interaction of heavy ion beams with a hydrogen plasma: plasma lens effect and stopping power enhancement

    International Nuclear Information System (INIS)

    Gardes, D.; Bimbot, R.; Della-Negra, S.; Dumail, M.; Kubica, B.; Richard, A.; Rivet, M.F.; Servajean, A.; Deutsch, C.; Maynard, G.

    1988-01-01

    By coupling a hydrogen plasma to a Tandem accelerator, transmission and energy losses of 2 MeV/u carbon and sulfur beams passing through a plasma target have been investigated. Fluctuations in beam transmission have been observed and attributed to a plasma lens effect. Moreover, energy loss measurements indicate an enhanced stopping power of the plasma relative to its cold matter equivalent

  18. Power in discursive practices: The case of the STOP EPAs campaign

    NARCIS (Netherlands)

    Del Felice, M.C.

    2014-01-01

    Transnational activism has increased in relation to international trade and development politics in the past decades, yet their power has been inadequately studied. This article analyses the STOP EPAs campaign (2004-2009) which aimed to influence the negotiations of Economic Partnership Agreements

  19. Stopping powers of gases for ions of energy below 200 keV

    International Nuclear Information System (INIS)

    Fukuda, Akira

    1978-01-01

    There has been renewed interest in the stopping power of matters for ions in low energy region. But there is not an established theory in this energy region, and experimental data did not coincide with the curves in some data books. Therefore, precise experimental measurement is still necessary. In present neutron dosimetry, tissues are the object of measurement of absorbed dose. In this experiment, it was intended to use tissue equivalent gas as a target gas. In the experimental apparatus, ions come from the Cockcroft-Walton accelerator are applied to the cell, in which the target gas is admitted from gas source. Gas in the cell is observed with the electrostatic energy analyzer. Stopping power is calculated from the results of energy loss measurement. In this report, only the preliminary results are shown. The tissue equivalent gas is composed of CH 4 , CO 2 and N 2 , each percentage is 64.95, 32.2 and 2.85, respectively. It seems that the stopping powers of noble gases will be useful for the developments of the theory, and the stopping power for He + ions was measured. The results are shown in a figure, and the errors were estimated to be less than 1.5%. At the end of the report, some discussions among a few persons are added. (Wakatsuki, Y.)

  20. Inventory of nuclear power plants and research reactors temporary or definitively stopped in industrialized countries

    International Nuclear Information System (INIS)

    Clauzon, J.; Vaubert, B.

    1984-12-01

    This paper presents data and information on the end of the life of nuclear reactors. One deals more particularly with installations of industrialized countries. This report gives the motivations which have involved the definitive shut down of nuclear power plants and of research reactors in the concerned countries. A schedule of definitive reactor shutdowns is presented. Then, one deals with nuclear power plants of which the construction has been stopped. The reasons of these situations are also given. The temporary difficulties met during the construction or the starting of nuclear power plants these last years are mentioned. Most times, there are economical or political considerations, or safety reasons. Finally, the nuclear power plants stopped for more than two years are mentioned [fr

  1. Power electronics a first course

    CERN Document Server

    Mohan, Ned

    2011-01-01

    Author Ned Mohan has been a leader in EES education and research for decades. His three-book series on Power Electronics focuses on three essential topics in the power sequence based on applications relevant to this age of sustainable energy such as wind turbines and hybrid electric vehicles. The three topics include power electronics, power systems and electric machines. Key features in the first Edition build on Mohan's successful MNPERE texts; his systems approach which puts dry technical detail in the context of applications; and substantial pedagogical support including PPT's, video clips, animations, clicker questions and a lab manual. It follows a top-down systems-level approach to power electronics to highlight interrelationships between these sub-fields. It's intended to cover fundamental and practical design. This book also follows a building-block approach to power electronics that allows an in-depth discussion of several important topics that are usually left. Topics are carefully sequenced to mai...

  2. Stopping Power of Be, Al, Cu, Ag, Pt, and Au for 5-12-MeV Protons and Deuterons

    DEFF Research Database (Denmark)

    Andersen, H.H.; Hanke, C.; Sørensen, H.

    1967-01-01

    Recent measurements on stopping power of aluminum have been continued with the stopping materials Be, Cu, Ag, Pt, and Au. The method of measuring stopping powers utilizing a thermometric compensation technique working at liquid-helium temperature has been used. Results are obtained with a standard...... deviation of 0.3%, and agree with other published experimental results and with Bichsel's tabulated values within their stated errors....

  3. Efficiency improvement in proton dose calculations with an equivalent restricted stopping power formalism

    Science.gov (United States)

    Maneval, Daniel; Bouchard, Hugo; Ozell, Benoît; Després, Philippe

    2018-01-01

    The equivalent restricted stopping power formalism is introduced for proton mean energy loss calculations under the continuous slowing down approximation. The objective is the acceleration of Monte Carlo dose calculations by allowing larger steps while preserving accuracy. The fractional energy loss per step length ɛ was obtained with a secant method and a Gauss-Kronrod quadrature estimation of the integral equation relating the mean energy loss to the step length. The midpoint rule of the Newton-Cotes formulae was then used to solve this equation, allowing the creation of a lookup table linking ɛ to the equivalent restricted stopping power L eq, used here as a key physical quantity. The mean energy loss for any step length was simply defined as the product of the step length with L eq. Proton inelastic collisions with electrons were added to GPUMCD, a GPU-based Monte Carlo dose calculation code. The proton continuous slowing-down was modelled with the L eq formalism. GPUMCD was compared to Geant4 in a validation study where ionization processes alone were activated and a voxelized geometry was used. The energy straggling was first switched off to validate the L eq formalism alone. Dose differences between Geant4 and GPUMCD were smaller than 0.31% for the L eq formalism. The mean error and the standard deviation were below 0.035% and 0.038% respectively. 99.4 to 100% of GPUMCD dose points were consistent with a 0.3% dose tolerance. GPUMCD 80% falloff positions (R80 ) matched Geant’s R80 within 1 μm. With the energy straggling, dose differences were below 2.7% in the Bragg peak falloff and smaller than 0.83% elsewhere. The R80 positions matched within 100 μm. The overall computation times to transport one million protons with GPUMCD were 31-173 ms. Under similar conditions, Geant4 computation times were 1.4-20 h. The L eq formalism led to an intrinsic efficiency gain factor ranging between 30-630, increasing with the prescribed accuracy of simulations. The

  4. Power Electronics Packaging Reliability | Transportation Research | NREL

    Science.gov (United States)

    Packaging Reliability Power Electronics Packaging Reliability A photo of a piece of power electronics laboratory equipment. NREL power electronics packaging reliability research investigates the electronics packaging around a semiconductor switching device determines the electrical, thermal, and

  5. Simplified derivation of stopping power ratio in the human body from dual-energy CT data.

    Science.gov (United States)

    Saito, Masatoshi; Sagara, Shota

    2017-08-01

    The main objective of this study is to propose an alternative parameterization for the empirical relation between mean excitation energies (I-value) and effective atomic numbers (Z eff ) of human tissues, and to present a simplified formulation (which we called DEEDZ-SPR) for deriving the stopping power ratio (SPR) from dual-energy (DE) CT data via electron density (ρ e ) and Z eff calibration. We performed a numerical analysis of this DEEDZ-SPR method for the human-body-equivalent tissues of ICRU Report 46, as objects of interest with unknown SPR and ρ e . The attenuation coefficients of these materials were calculated using the XCOM photon cross-sections database. We also applied the DEEDZ-SPR conversion to experimental DECT data available in the literature, which was measured for the tissue-characterization phantom using a dual-source CT scanner at 80 kV and 140 kV/Sn. It was found that the DEEDZ-SPR conversion enables the calculation of SPR simply by means of the weighted subtraction of an electron-density image and a low- or high-kV CT image. The simulated SPRs were in excellent agreement with the reference values over the SPR range from 0.258 (lung) to 3.638 (bone mineral-hydroxyapatite). The relative deviations from the reference SPR were within ±0.6% for all ICRU-46 human tissues, except for the thyroid that presented a -1.1% deviation. The overall root-mean-square error was 0.21%. Application to experimental DECT data confirmed this agreement within the experimental accuracy, which demonstrates the practical feasibility of the method. The DEEDZ-SPR conversion method could facilitate the construction of SPR images as accurately as a recent DECT-based calibration procedure of SPR parameterization based directly on the CT numbers in a DECT data set. © 2017 American Association of Physicists in Medicine.

  6. Ablation of a Deuterium Pellet in a Fusion Plasma Viewed as a Stopping Power Problem

    DEFF Research Database (Denmark)

    Chang, C. T.

    1983-01-01

    At present, the most exploited technology to refuel a future fusion reactor is the high speed injection of macroscopic size pellet of solid hydrogen isotopes. The basic idea is that the ablation of a pellet in a fusion reactor is mainly caused by thermal electrons (~ 10 keV) /1/. Due to the low...... sublimation energy of hydrogen isotopes, shortly after the direct impact of the electrons, a dense cloud forms around the pellet. This cloud of ablated material then serves as a stopping medium for the incoming electrons, thus prolongs the pellet life-time. As a result, the deep penetration of the pellet...

  7. Power electronics cooling apparatus

    Science.gov (United States)

    Sanger, Philip Albert; Lindberg, Frank A.; Garcen, Walter

    2000-01-01

    A semiconductor cooling arrangement wherein a semiconductor is affixed to a thermally and electrically conducting carrier such as by brazing. The coefficient of thermal expansion of the semiconductor and carrier are closely matched to one another so that during operation they will not be overstressed mechanically due to thermal cycling. Electrical connection is made to the semiconductor and carrier, and a porous metal heat exchanger is thermally connected to the carrier. The heat exchanger is positioned within an electrically insulating cooling assembly having cooling oil flowing therethrough. The arrangement is particularly well adapted for the cooling of high power switching elements in a power bridge.

  8. Transients of modern power electronics

    CERN Document Server

    Bai, Hua

    2011-01-01

    In high power, high voltage electronics systems, a strategy to manage short timescale energy imbalances is fundamental to the system reliability. Without a theoretical framework, harmful local convergence of energy can affect the dynamic process of transformation, transmission, and storage which create an unreliable system. With an original approach that encourages understanding of both macroscopic and microscopic factors, the authors offer a solution. They demonstrate the essential theory and methodology for the design, modeling and prototyping of modern power electronics converters to crea

  9. Measuring the stopping power of α particles in compact bone for BNCT

    Science.gov (United States)

    Provenzano, L.; Rodríguez, L. M.; Fregenal, D.; Bernardi, G.; Olivares, C.; Altieri, S.; Bortolussi, S.; González, S. J.

    2015-01-01

    The stopping power of α particles in thin films of decalcified sheep femur, in the range of 1.5 to 5.0 MeV incident energy, was measured by transmission of a backscattered beam from a heavy target. Additionally, the film elemental composition was determined by Rutherford Backscattering Spectrometry (RBS). These data will be used to measure boron concentration in thin films of bone using a spectrometry technique developed by the University of Pavia, since the concentration ratio between healthy tissue and tumor is of fundamental importance in Boron Neutron Capture Therapy (BNCT). The present experimental data are compared with numerical simulation results and with tabulated stopping power data of non-decalcified human bone.

  10. Calculation of the stopping power and the path of charged particles in matter. Application example

    International Nuclear Information System (INIS)

    Barre, Bertrand; Du Lieu, Pierre

    1969-05-01

    The path of a charged particle in matter is calculated by integrating the stopping power of the medium against this particle. Depending on the energy of the particle, stopping powers are calculated using Lindhard, Bethe, or semi-empirical smoothing solutions. After exposing recent theories in this field, the authors present a Fortran subroutine which performs these various operations, and covers all energy domains. This routine is available for operation on IBM 360; it uses a magnetic tape library that can take into account experimental results. The subprogram presentation, leaving the user the option of entering the data and using the results at his discretion, allows a particularly flexible use. At the end of this note, some considerations on possible further improvements in the program, and a bibliography of the articles that have dealt with the question from a theoretical or an experimental point of view are discussed [fr

  11. Investigation of the influence of intermolecular interactions on the electronic stopping cross sections

    International Nuclear Information System (INIS)

    Krotz, R.; Neuwirth, W.; Pietsch, W.

    1980-01-01

    The electronic stopping cross sections for Li projectiles have been measured in various kinds of targets. They are analyzed here with respect to the different types of interactions between the constituents of the target: interactions between the atoms in a compound (chemical bonding), the ion-dipole interaction, if the target is an electrolytic solution, and the dipole-dipole interaction among polar molecules. The influence on the stopping cross section depends on the strength of these interactions; it varies from a few percent in the latter case up to 20% and more in a compound. These influences are the largest, if the velocity of the projectile is of the order of the average orbital velocity of the target atoms. (author)

  12. Exploring reciprocity as a tool in low-energy electronic stopping

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmin, Valery [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Sigmund, Peter [Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M (Denmark)

    2011-05-01

    A computer code has been developed to explore reciprocity, i.e. the equivalence of electronic stopping cross sections for the ion-target pair A in B with that for B in A in the regime around and below the Bohr speed. With the aim of establishing reciprocity as a tool for identifying reliable experimental data and interpolating between them, we have studied stopping cross sections involving carbon, aluminium and gold either as projectile ions or as target materials. The case of carbon - where numerous data are available - is used to illustrate in detail various options to establish a body of credible data. Aluminium and gold serve to illustrate the case where these elements mostly are found as target materials in available data.

  13. The Barkas effect and other higher-order Z1-contributions to the stopping power

    International Nuclear Information System (INIS)

    Andersen, H.H.

    1985-01-01

    The experimental evidence for contributions to the stopping power proportional to Z 1 3 (Barkas effect) and Z 1 4 (Bloch correction) at velocities around 10 v 0 is reviewed. Quantitative evidence is found for both terms but it is not possible experimentally to discern whether hard collisions contribute to the Barkas term. Evidence from single-collision events are drawn into the discussion and some experiments which may turn out to be decisive are discussed. (orig.)

  14. Stopping-power and mass energy-absorption coefficient ratios for Solid Water

    International Nuclear Information System (INIS)

    Ho, A.K.; Paliwal, B.R.

    1986-01-01

    The AAPM Task Group 21 protocol provides tables of ratios of average restricted stopping powers and ratios of mean energy-absorption coefficients for different materials. These values were based on the work of Cunningham and Schulz. We have calculated these quantities for Solid Water (manufactured by RMI), using the same x-ray spectra and method as that used by Cunningham and Schulz. These values should be useful to people who are using Solid Water for high-energy photon calibration

  15. Stopping power and range relations for low and high Z ions in solids: a critical analysis

    International Nuclear Information System (INIS)

    Virk, H.S.; Randhawa, G.S.

    1997-01-01

    A critical analysis of various stopping power and range formulations has been made by comparing the calculated stopping power and range values with corresponding experimental values for different low Z (1≤Z≤8) and high Z projectiles (54≤Z≤92) in different targets, e.g. Be, C, Al, Au, Pb, CR-39, Lexan, Mylar, LR-115, CH, (CH)n, TRIFOL-TN, etc. atvarious low and high energies. A comparative study has been made by taking into consideration different target and projectile combinations, e.g., heavy ion-light target, light ion-heavy target and light ion -light target etc., Overall the Ziegler formulation (TRIM-95) provides the best agreement with the experimental results for all projectile and target combinations except for heavy ion-light target combination where it underestimates the stopping power data and overestimates the range data in the range, 2-50 MeV/u. Mukherjee and Nayak formulation totally fails at relativistic and low energies of the projectile, irrespective of the projectile-target combination. Northcliffe and Schilling formulation does not show any particular trend. Benton and Henke formulation gives good agreement between experimental and theoretical data within the range of experimental errors. (orig.)

  16. The measurement of proton stopping power using proton-cone-beam computed tomography

    International Nuclear Information System (INIS)

    Zygmanski, P.; Rabin, M.S.Z.; Gall, K.P.; Rosenthal, S.J.

    2000-01-01

    A cone-beam computed tomography (CT) system utilizing a proton beam has been developed and tested. The cone beam is produced by scattering a 160 MeV proton beam with a modifier that results in a signal in the detector system, which decreases monotonically with depth in the medium. The detector system consists of a Gd 2 O 2 S:Tb intensifying screen viewed by a cooled CCD camera. The Feldkamp-Davis-Kress cone-beam reconstruction algorithm is applied to the projection data to obtain the CT voxel data representing proton stopping power. The system described is capable of reconstructing data over a 16x16x16cm 3 volume into 512x512x512 voxels. A spatial and contrast resolution phantom was scanned to determine the performance of the system. Spatial resolution is significantly degraded by multiple Coulomb scattering effects. Comparison of the reconstructed proton CT values with x-ray CT derived proton stopping powers shows that there may be some advantage to obtaining stopping powers directly with proton CT. The system described suggests a possible practical method of obtaining this measurement in vivo. (author)

  17. Formulae for the secondary electron yield and total stopping power ...

    Indian Academy of Sciences (India)

    2Department of Electrical and Biological Physics, Kwangwoon University, 20 Kwangwoon-gil, ..... sample preparation techniques can lead to different ... talline orientation, contamination or submonolayer on the surface of foreign species; a.

  18. Power Electronics and Electric Machines Facilities | Transportation

    Science.gov (United States)

    Research | NREL Facilities Power Electronics and Electric Machines Facilities NREL's power electronics and electric machines thermal management experimentation facilities feature a wide range of four researchers in discussion around a piece of laboratory equipment. Power electronics researchers

  19. Perceptions towards electronic cigarettes for smoking cessation among Stop Smoking Service users.

    Science.gov (United States)

    Sherratt, Frances C; Newson, Lisa; Marcus, Michael W; Field, John K; Robinson, Jude

    2016-05-01

    Electronic cigarettes (e-cigarettes) are promoted as smoking cessation tools, yet they remain unavailable from Stop Smoking Services in England; the debate over their safety and efficacy is ongoing. This study was designed to explore perceptions and reasons for use or non-use of electronic cigarettes as smoking cessation tools, among individuals engaged in Stop Smoking Services. Semi-structured telephone interviews were undertaken with twenty participants engaged in Stop Smoking Services in the north-west of England. Participants comprised of both individuals who had tried e-cigarettes (n = 6) and those who had not (n = 14). Interviews were digitally recorded and transcribed verbatim. The transcripts were subject to thematic analysis, which explored participants' beliefs and experiences of e-cigarettes. A thematic analysis of transcripts suggested that the following three superordinate themes were prominent: (1) self-efficacy and beliefs in e-cigarettes; (2) e-cigarettes as a smoking cessation aid; and (3) cues for e-cigarette use. Participants, particularly never users, were especially concerned regarding e-cigarette efficacy and safety. Overall, participants largely expressed uncertainty regarding e-cigarette safety and efficacy, with some evidence of misunderstanding. Evidence of uncertainty and misunderstanding regarding information on e-cigarettes highlights the importance of providing smokers with concise, up-to-date information regarding e-cigarettes, enabling smokers to make informed treatment decisions. Furthermore, identification of potential predictors of e-cigarette use can be used to inform Stop Smoking Services provision and future research. What is already known on this subject? Research suggests that e-cigarettes may help smokers quit smoking, but further studies are needed. Electronic cigarette use in Stop Smoking Services has increased substantially in recent years, although e-cigarettes are currently not regulated. There is debate within the

  20. Ex vivo validation of a stoichiometric dual energy CT proton stopping power ratio calibration

    Science.gov (United States)

    Xie, Yunhe; Ainsley, Christopher; Yin, Lingshu; Zou, Wei; McDonough, James; Solberg, Timothy D.; Lin, Alexander; Teo, Boon-Keng Kevin

    2018-03-01

    A major source of uncertainty in proton therapy is the conversion of Hounsfield unit (HU) to proton stopping power ratio relative to water (SPR). In this study, we measured and quantified the accuracy of a stoichiometric dual energy CT (DECT) SPR calibration. We applied a stoichiometric DECT calibration method to derive the SPR using CT images acquired sequentially at 80 kVp and 140 kVp . The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the effective atomic number (Z eff), relative electron density ({{ρ }e} ), and SPRs of phantom and biological materials. Two methods were used to verify the derived SPRs. The first method measured the sample’s water equivalent thicknesses to deduce the SPRs using a multi-layer ion chamber (MLIC) device. The second method utilized Gafchromic EBT3 film to directly compare relative ranges between sample and water after proton pencil beam irradiation. Ex vivo validation was performed using five different types of frozen animal tissues with the MLIC and three types of fresh animal tissues using film. In addition, the residual ranges recorded on the film were used to compare with those from the treatment planning system using both DECT and SECT derived SPRs. Bland-Altman analysis indicates that the differences between DECT and SPR measurement of tissue surrogates, frozen and fresh animal tissues has a mean of 0.07% and standard deviation of 0.58% compared to 0.55% and 1.94% respectively for single energy CT (SECT) and SPR measurement. Our ex vivo study indicates that the stoichiometric DECT SPR calibration method has the potential to be more accurate than SECT calibration under ideal conditions although beam hardening effects and other image artifacts may increase this uncertainty.

  1. Atmospheric Muon Lifetime, Standard Model of Particles and the Lead Stopping Power for Muons

    Science.gov (United States)

    Gutarra-Leon, Angel; Barazandeh, Cioli; Majewski, Walerian

    2017-01-01

    The muon is a fundamental particles of matter. It decays into three other leptons through an exchange of the weak vector bosons W +/W-. Muons are present in the atmosphere from cosmic ray showers. By detecting the time delay between arrival of the muon and an appearance of the decay electron in our detector, we'll measure muon's lifetime at rest. From the lifetime we should be able to find the ratio gw /MW of the weak coupling constant gw (a weak analog of the electric charge) to the mass of the W-boson MW. Vacuum expectation value v of the Higg's field, which determines the masses of all particles of the Standard Model (SM), could be then calculated from our muon experiment as v =2MWc2/gw =(τ m μc2/6 π3ĥ)1/4m μc2 in terms of muon mass mµand muon lifetime τ only. Using known experimental value for MWc2 = 80.4 GeV we'll find the weak coupling constant gw. Using the SM relation e =gwsin θ√ hc ɛ0 with the experimental value of the Z0-photon weak mixing angle θ = 29o we could find from our muon lifetime the value of the elementary electric charge e. We'll determine the sea-level fluxes of low-energy and high-energy cosmic muons, then we'll shield the detector with varying thicknesses of lead plates and find the energy-dependent muon stopping power in lead.

  2. Highly accurate nuclear and electronic stopping cross sections derived using Monte Carlo simulations to reproduce measured range data

    Science.gov (United States)

    Wittmaack, Klaus; Mutzke, Andreas

    2017-03-01

    We have examined and confirmed the previously unexplored concept of using Monte Carlo calculations in combination with measured projected ranges of ions implanted in solids to derive a quantitative description of nuclear interaction and electronic stopping. The study involved 98 ranges of 11B in Si between 1 keV and 8 MeV, contained in 12 sets of 10 different groups. Systematic errors by up to ±8% were removed to establish a refined data base with 93 ranges featuring only statistical uncertainties (±1.8%). The Monte Carlo calculations could be set up to reproduce the refined ranges with a mean ratio 1.002 ± 1.7%. The input parameters required for this very high level of agreement are as follows. Nuclear interaction is best described by the Kr-C potential, but in obligatory combination with the Lindhard-Scharff (LS) screening length. Up to 300 keV, the electronic stopping cross section is proportional to the projectile velocity, Se = kSe,LS, with k = 1.46 ± 0.01. At higher energies, Se falls progressively short of kSe,LS. Around the Bragg peak, i.e., between 0.8 and 10 MeV, Se is modeled by an adjustable function serving to tailor the peak shape properly. Calculated and measured isotope effects for ranges of 10B and 11B in Si agree within the experimental uncertainty (±0.25%). The range-based Se,R(E) reported here predicts the scarce experimental data derived from the energy loss in projectile transmission through thin Si foils to within 2% or better. By contrast, Se(E) data of available stopping power tables exhibit deviations from Se,R(E) between -40% and +14%.

  3. A Review of Power Electronics for Wind Power

    Institute of Scientific and Technical Information of China (English)

    Zhe CHEN

    2011-01-01

    The paper reviews the power electronic applications for wind energy systems.Main wind turbine systems with different generators and power electronic converters are described.The electrical topologies of wind farms with power electronic conversion are discussed.Power electronic applications for improving the performance of wind turbines and wind farms in power systems have been illustrated.

  4. 78 FR 15714 - Welch Motel, Inc., Welch Oil, Inc., Boondocks USA Truck Stop, Bob Welch v. Midland Power...

    Science.gov (United States)

    2013-03-12

    ..., Inc., Welch Oil, Inc., Boondocks USA Truck Stop, Bob Welch v. Midland Power Cooperative, Corn Belt..., Welch Motel, Inc., Welch Oil, Inc., Boondocks USA Truck Stop, and Bob Welch (collectively, Complainants... into a contract to consume all of the electric energy and capacity generated by [[Page 15715...

  5. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2015-07-01

    The stopping power and energy straggling of {sup 12}C{sup 3+} and {sup 16}O{sup 3+} ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C{sup 3+} ion energy losses comparing to O{sup 3+} ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%.

  6. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    International Nuclear Information System (INIS)

    Mikšová, R.; Hnatowicz, V.; Macková, A.; Malinský, P.; Slepička, P.

    2015-01-01

    The stopping power and energy straggling of 12 C 3+ and 16 O 3+ ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C 3+ ion energy losses comparing to O 3+ ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%

  7. Stopping power and polarization induced in a plasma by a fast charged particle in circular motion

    Energy Technology Data Exchange (ETDEWEB)

    Villo-Perez, Isidro [Departamento de Electronica, Tecnologia de las Computadoras y Proyectos, Universidad Politecnica de Cartagena, Cartagena (Spain); Arista, Nestor R. [Division Colisiones Atomicas, Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, Bariloche (Argentina); Garcia-Molina, Rafael [Departamento de Fisica, Universidad de Murcia, Murcia (Spain)

    2002-03-28

    We describe the perturbation induced in a plasma by a charged particle in circular motion, analysing in detail the evolution of the induced charge, the electrostatic potential and the energy loss of the particle. We describe the initial transitory behaviour and the different ways in which convergence to final stationary solutions may be obtained depending on the basic parameters of the problem. The results for the stopping power show a resonant behaviour which may give place to large stopping enhancement values as compared with the case of particles in straight-line motion with the same linear velocity. The results also explain a resonant effect recently obtained for particles in circular motion in magnetized plasmas. (author)

  8. Modified energy-deposition model, for the computation of the stopping-power ratio for small cavity sizes

    International Nuclear Information System (INIS)

    Janssens, A.C.A.

    1981-01-01

    This paper presents a modification to the Spencer-Attix theory, which allows application of the theory to larger cavity sizes. The modified theory is in better agreement with the actual process of energy deposition by delta rays. In the first part of the paper it is recalled how the Spencer-Attix theory can be derived from basic principles, which allows a physical interpretation of the theory in terms of a function describing the space and direction average of the deposited energy. A realistic model for the computation of this function is described and the resulting expression for the stopping-power ratio is calculated. For the comparison between the Spencer-Attix theory and this modified expression a correction factor to the ''Bragg-Gray inhomogeneous term'' has been defined. This factor has been computed as a function of cavity size for different source energies and mean excitation energies; thus, general properties of this factor have been elucidated. The computations have been extended to include the density effect. It has been shown that the computation of the inhomogeneous term can be performed for any expression describing the energy loss per unit distance of the electrons as a function of their energy. Thus an expression has been calculated which is in agreement with a quadratic range-energy relationship. In conclusion, the concrete procedure for computing the stopping-power ratio is reviewed

  9. Low inductance power electronics assembly

    Science.gov (United States)

    Herron, Nicholas Hayden; Mann, Brooks S.; Korich, Mark D.; Chou, Cindy; Tang, David; Carlson, Douglas S.; Barry, Alan L.

    2012-10-02

    A power electronics assembly is provided. A first support member includes a first plurality of conductors. A first plurality of power switching devices are coupled to the first support member. A first capacitor is coupled to the first support member. A second support member includes a second plurality of conductors. A second plurality of power switching devices are coupled to the second support member. A second capacitor is coupled to the second support member. The first and second pluralities of conductors, the first and second pluralities of power switching devices, and the first and second capacitors are electrically connected such that the first plurality of power switching devices is connected in parallel with the first capacitor and the second capacitor and the second plurality of power switching devices is connected in parallel with the second capacitor and the first capacitor.

  10. Direct cooled power electronics substrate

    Science.gov (United States)

    Wiles, Randy H [Powell, TN; Wereszczak, Andrew A [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Lowe, Kirk T [Knoxville, TN

    2010-09-14

    The disclosure describes directly cooling a three-dimensional, direct metallization (DM) layer in a power electronics device. To enable sufficient cooling, coolant flow channels are formed within the ceramic substrate. The direct metallization layer (typically copper) may be bonded to the ceramic substrate, and semiconductor chips (such as IGBT and diodes) may be soldered or sintered onto the direct metallization layer to form a power electronics module. Multiple modules may be attached to cooling headers that provide in-flow and out-flow of coolant through the channels in the ceramic substrate. The modules and cooling header assembly are preferably sized to fit inside the core of a toroidal shaped capacitor.

  11. High Power Electron Accelerator Prototype

    CERN Document Server

    Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

    2005-01-01

    In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

  12. Measurement of stopping powers of gases for heavy ions of 3 to 13 MeV by nucleon

    International Nuclear Information System (INIS)

    Orliange, I.

    1985-09-01

    The stopping powers of gases have been measured for incident 10 Ne, 18 Ar, 29 Cu, 36 Kr and 47 Ag ions of 3 to 13 MeV/u. These measurements have confirmed the existence of a gas-solid difference for the stopping powers (the stopping power of solids being larger than that of gazes). Such a difference was theoretically postulated by Bohr and Lindhard in 1954, and experimentally observed for the first time by Geissel in 1982. This effect can be qualitatively interpreted by a difference in the ion's effective charge in stopping power. However, the determination of charge state distribution for Ar and Fe ions in two particular cases (Ar + Nsub(2s)or Nsub(2g) and (Fe + Csub(s) or Csub(g)) from a theoric model and experimental cross sections for atomic collisions don't quantitatively account for observed differences [fr

  13. On the treatment of light-ion electronic stopping in dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Schiwietz, G. (Hahn-Meitner-Inst. Berlin GmbH, Div., FD (Germany)); Grande, P.L. (Hahn-Meitner-Inst. Berlin GmbH, Div., FD (Germany))

    1994-05-01

    A review is given on single-electron mechanisms and the corresponding theoretical approaches describing the electronic energy-transfer processes of light ions in gases and solids. Special emphasis is given to a discussion on the connection between exact Bloch-wave treatments and free-atom approximations. In the case of solids, perturbation theory is applied to the stopping of low-energy ions in the alkaline metals Li and Na. These calculations include Bloch wavefunctions of the Wigner-Seitz type obtained from a Hartree-Fock-Slater calculation and allow for a prediction of the mean energy loss under channeling conditions. Results of the most widely used local-density approximation are compared to data of our more complete perturbative treatment. Comparison is also made with recent LCAO calculations. (orig.)

  14. SU-G-TeP1-02: Analytical Stopping Power and Range Parameterization for Therapeutic Energy Intervals

    Energy Technology Data Exchange (ETDEWEB)

    Donahue, W [Louisiana State University, Baton Rouge, LA (United States); Newhauser, W [Louisiana State University, Baton Rouge, LA (United States); Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Ziegler, J F [United States Naval Academy, Annapolis, MD (United States)

    2016-06-15

    Purpose: To develop a simple, analytic parameterization of stopping power and range, which covers a wide energy interval and is applicable to many species of projectile ions and target materials, with less than 15% disagreement in linear stopping power and 1 mm in range. Methods: The new parameterization was required to be analytically integrable from stopping power to range, and continuous across the range interval of 1 µm to 50 cm. The model parameters were determined from stopping power and range data for hydrogen, carbon, iron, and uranium ions incident on water, carbon, aluminum, lead and copper. Stopping power and range data was taken from SRIM. A stochastic minimization algorithm was used to find model parameters, with 10 data points per energy decade. Additionally, fitting was performed with 2 and 26 data points per energy decade to test the model’s robustness to sparse Results: 6 free parameters were sufficient to cover the therapeutic energy range for each projectile ion species (e.g. 1 keV – 300 MeV for protons). The model agrees with stopping power and range data well, with less than 9% relative stopping power difference and 0.5 mm difference in range. As few as, 4 bins per decade were required to achieve comparable fitting results to the full data set. Conclusion: This study successfully demonstrated that a simple analytic function can be used to fit the entire energy interval of therapeutic ion beams of hydrogen and heavier elements. Advantages of this model were the small number (6) of free parameters, and that the model calculates both stopping power and range. Applications of this model include GPU-based dose calculation algorithms and Monte Carlo simulations, where available memory is limited. This work was supported in part by a research agreement between United States Naval Academy and Louisiana State University: Contract No N00189-13-P-0786. In addition, this work was accepted for presentation at the American Nuclear Society Annual Meeting

  15. SU-G-TeP1-02: Analytical Stopping Power and Range Parameterization for Therapeutic Energy Intervals

    International Nuclear Information System (INIS)

    Donahue, W; Newhauser, W; Ziegler, J F

    2016-01-01

    Purpose: To develop a simple, analytic parameterization of stopping power and range, which covers a wide energy interval and is applicable to many species of projectile ions and target materials, with less than 15% disagreement in linear stopping power and 1 mm in range. Methods: The new parameterization was required to be analytically integrable from stopping power to range, and continuous across the range interval of 1 µm to 50 cm. The model parameters were determined from stopping power and range data for hydrogen, carbon, iron, and uranium ions incident on water, carbon, aluminum, lead and copper. Stopping power and range data was taken from SRIM. A stochastic minimization algorithm was used to find model parameters, with 10 data points per energy decade. Additionally, fitting was performed with 2 and 26 data points per energy decade to test the model’s robustness to sparse Results: 6 free parameters were sufficient to cover the therapeutic energy range for each projectile ion species (e.g. 1 keV – 300 MeV for protons). The model agrees with stopping power and range data well, with less than 9% relative stopping power difference and 0.5 mm difference in range. As few as, 4 bins per decade were required to achieve comparable fitting results to the full data set. Conclusion: This study successfully demonstrated that a simple analytic function can be used to fit the entire energy interval of therapeutic ion beams of hydrogen and heavier elements. Advantages of this model were the small number (6) of free parameters, and that the model calculates both stopping power and range. Applications of this model include GPU-based dose calculation algorithms and Monte Carlo simulations, where available memory is limited. This work was supported in part by a research agreement between United States Naval Academy and Louisiana State University: Contract No N00189-13-P-0786. In addition, this work was accepted for presentation at the American Nuclear Society Annual Meeting

  16. Electromagnetic compatibility in power electronics

    CERN Document Server

    Costa , François; Revol , Bertrand

    2014-01-01

    Scientists largely attribute the recent deterioration of the electromagnetic environment to power electronics. This realization has spurred the study of methodical approaches to electromagnetic compatibility designs as explored in this text. The book addresses major challenges, such as handling numerous parameters vital to predicting electro magnetic effects and achieving compliance with line-harmonics norms, while proposing potential solutions.

  17. Power Electronics Thermal Management | Transportation Research | NREL

    Science.gov (United States)

    Power Electronics Thermal Management Power Electronics Thermal Management A photo of water boiling in liquid cooling lab equipment. Power electronics thermal management research aims to help lower the investigates and develops thermal management strategies for power electronics systems that use wide-bandgap

  18. An apparatus to measure stopping powers for low-energy antiprotons and protons

    CERN Document Server

    Andersen, H H; Ichioka, T; Knudsen, H; Møller, S P; Uggerhøj, U

    2002-01-01

    One of the experiments to be performed under the ASACUSA collaboration at the CERN Antiproton Decelerator is a measurement of the energy loss of low energy antiprotons in thin foils. An electrostatic spectrometer has been developed for this task. We describe the design and initial tests of the apparatus with protons. By changing a high-voltage applied on the target the energy of the projectile ions at impact on the target can easily be varied. In this way we have measured the stopping-power and the energy-loss straggling for protons over a wide energy range to below one keV.

  19. Quiet: The Power of Introvert in a World That Can’t Stop Talking

    OpenAIRE

    Sean Schat

    2012-01-01

    Do you pay attention to the differences between extroversion and introversion? It can be fascinating to consider who is and is not aware of  the distinction between the two, as well as the significant formative role they both play in daily perceptions and interactions.  In my experience, more often than not it is the introverts who recognize and appreciate the difference, while too many extroverts remain unaware. In  Quiet: The Power of Introverts in a World That Can’t Stop Talking(2012), Sus...

  20. High post-movement parietal low-beta power during rhythmic tapping facilitates performance in a stop task.

    Science.gov (United States)

    Fischer, Petra; Tan, Huiling; Pogosyan, Alek; Brown, Peter

    2016-09-01

    Voluntary movements are followed by a post-movement electroencephalography (EEG) beta rebound, which increases with practice and confidence in a task. We hypothesized that greater beta modulation reflects less load on cognitive resources and may thus be associated with faster reactions to new stimuli. EEG was recorded in 17 healthy subjects during rhythmically paced index finger tapping. In a STOP condition, participants had to interrupt the upcoming tap in response to an auditory cue, which was timed such that stopping was successful only in ~ 50% of all trials. In a second condition, participants carried on tapping twice after the stop signal (CONTINUE condition). Thus the conditions were distinct in whether abrupt stopping was required as a second task. Modulation of 12-20 Hz power over motor and parietal areas developed with time on each trial and more so in the CONTINUE condition. Reduced modulation in the STOP condition went along with reduced negative mean asynchronies suggesting less confident anticipation of the timing of the next tap. Yet participants were more likely to stop when beta modulation prior to the stop cue was more pronounced. In the STOP condition, expectancy of the stop signal may have increased cognitive load during movement execution given that the task might have to be stopped abruptly. However, within this condition, stopping ability was increased if the preceding tap was followed by a relatively larger beta increase. Significant, albeit weak, correlations confirmed that increased post-movement beta power was associated with faster reactions to new stimuli, consistent with reduced cognitive load. © 2016 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  1. Electronic Power Transformer for Power Distribution Networks

    Directory of Open Access Journals (Sweden)

    Ermuraсhi Iu.V.

    2017-12-01

    Full Text Available Reducing losses in electricity distribution networks is a current technical problem. This issue also has social and environmental aspects. As a promising solution one can examine the direct distribution from the medium voltage power network using new equipment based on the use of power electronics. The aim of the paper is to propose and argue an innovative technical solution for the realization of the Solid State Transformer (SST in order to decrease the number of energy transformation stages compared to the known solutions, simplifying the topology of the functional scheme with the reduction of production costs and the loss of energy in transformers used in electrical distribution networks. It is proposed the solution of simplifying the topology of the AC/AC electronic transformer by reducing the number of passive electronic components (resistors, inductors, capacitors and active (transistors. The inverter of the SST transformer ensures the switching mode of the transistors, using for this purpose the inductance of the magnetic leakage flux of the high frequency transformer. The robustness of the laboratory sample of the SST 10 / 0.22 kV transformer with the power of 20 kW was manufactured and tested. Testing of the laboratory sample confirmed the functionality of the proposed scheme and the possibility of switching of the transistors to at zero current (ZCS mode with the reduction of the energy losses. In the proposed converter a single high-frequency transformer with a simplified construction with two windings is used, which reduces its mass and the cost of making the transformer. The reduction in the manufacturing cost of the converter is also due to the decrease in the number of links between the functional elements.

  2. Wind Power - A Power Source Enabled by Power Electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe

    2004-01-01

    . The deregulation of energy has lowered the investment in bigger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production sources from......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. The production, distribution and the use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should be set up...... the conventional, fossil (and short term) based energy sources to renewable energy sources. The other is to use high efficient power electronics in power systems, power production and end-user application. This paper discuss the most emerging renewable energy source, wind energy, which by means of power...

  3. Simulations of the energy loss of ions at the stopping-power maximum in a laser-induced plasma

    International Nuclear Information System (INIS)

    Cayzac, W.; Malka, G.; Frank, A.; Bagnoud, V.; Blažević, A.; Schlegel, T.; Ortner, A.; Bedacht, S.; Deppert, O.; Knetsch, A.; Schaumann, G.; Wagner, F.; Basko, M.M.; Gericke, D.O.; Hallo, L.; Pépitone, K.; Kraus, D.; Schumacher, D.; Tauschwitz, An.; Vorberger, J.

    2016-01-01

    Simulations have been performed to study the energy loss of carbon ions in a hot, laser-generated plasma in the velocity region of the stopping-power maximum. In this parameter range, discrepancies of up to 30% exist between the various stopping theories and hardly any experimental data are available. The considered plasma, created by irradiating a thin carbon foil with two high-energy laser beams, is fully-ionized with a temperature of nearly 200 eV. To study the interaction at the maximum stopping power, Monte-Carlo calculations of the ion charge state in the plasma are carried out at a projectile energy of 0.5 MeV per nucleon. The predictions of various stopping-power theories are compared and experimental campaigns are planned for a first-time theory benchmarking in this low-velocity range. (paper)

  4. Starting and stopping control on power conditioner in photovoltaic power system; Taiyoko hatsuden system ni okeru power conditioner no kido teishi seigyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, M.; Ishihara, Y.; Todaka, T.; Harada, K. [Doshisha University, Kyoto (Japan); Oshiro, H.; Nakamura, H. [Japan Quality Assurance Organization, Tokyo (Japan)

    1997-11-25

    Studies are made about the control of the power conditioner over the maximum power point tracking (MPPT) function in a photovoltaic power generation system. The analysis is conducted by means of computer simulation into the effect of a start/stop function added to the control of MPPT and the effect on the generation of power of the setting of parameters in the start/stop function. The reduction in output power due to difference between the actual operation point and the optimum operation point is evaluated by use of a load matching correction factor. In this simulation, it is assumed that the solar cell array consists of 13 rows in 5 parallel columns, is capable of a normal output of 3.149kW, has a panel tilted at 30 degrees, and faces due south. The power conditioner is assumed to be a system rated at 3kVA, equipped with system interconnection and back flow features. As a result, it is learned that the stop voltage should be set at 180V or lower and the steady voltage near 185.5V for a good result and that there is not much need after all for the start/stop technique. 2 refs., 8 figs., 2 tabs.

  5. Wind power - a power source now enabled by power electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Iov, Florin

    2007-01-01

    energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save...... the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging...

  6. The stopping powers and energy straggling of heavy ions in polymer foils

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2014-07-15

    The stopping power and energy straggling of {sup 7}Li, {sup 12}C and {sup 16}O ions in thin poly(etheretherketone) (PEEK), polyethylene terephthalate (PET) and polycarbonate (PC) foils were measured in the incident beam energy range of 9.4–11.8 MeV using an indirect transmission method. Ions scattered from a thin gold target at an angle of 150° were registered by a partially depleted PIPS detector, partly shielded with a polymer foil placed in front of the detector. Therefore, the signals from both direct and slowed down ions were visible in the same energy spectrum, which was evaluated by the ITAP code, developed at our laboratory. The ITAP code was employed to perform a Gaussian-fitting procedure to provide a complete analysis of each measured spectrum. The measured stopping powers were compared with the predictions obtained from the SRIM-2008 and MSTAR codes and with previous experimental data. The energy straggling data were compared with those calculated by using Bohr’s, Lindhard–Scharff and Bethe–Livingston theories.

  7. The stopping powers and energy straggling of heavy ions in polymer foils

    International Nuclear Information System (INIS)

    Mikšová, R.; Macková, A.; Malinský, P.; Hnatowicz, V.; Slepička, P.

    2014-01-01

    The stopping power and energy straggling of 7 Li, 12 C and 16 O ions in thin poly(etheretherketone) (PEEK), polyethylene terephthalate (PET) and polycarbonate (PC) foils were measured in the incident beam energy range of 9.4–11.8 MeV using an indirect transmission method. Ions scattered from a thin gold target at an angle of 150° were registered by a partially depleted PIPS detector, partly shielded with a polymer foil placed in front of the detector. Therefore, the signals from both direct and slowed down ions were visible in the same energy spectrum, which was evaluated by the ITAP code, developed at our laboratory. The ITAP code was employed to perform a Gaussian-fitting procedure to provide a complete analysis of each measured spectrum. The measured stopping powers were compared with the predictions obtained from the SRIM-2008 and MSTAR codes and with previous experimental data. The energy straggling data were compared with those calculated by using Bohr’s, Lindhard–Scharff and Bethe–Livingston theories

  8. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark.

    Science.gov (United States)

    Hansen, David C; Seco, Joao; Sørensen, Thomas Sangild; Petersen, Jørgen Breede Baltzer; Wildberger, Joachim E; Verhaegen, Frank; Landry, Guillaume

    2015-01-01

    Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in development) have both been proposed as methods for obtaining patient stopping power maps. The purpose of this work was to assess the accuracy of proton CT using dual energy CT scans of phantoms to establish reference accuracy levels. A CT calibration phantom and an abdomen cross section phantom containing inserts were scanned with dual energy and single energy CT with a state-of-the-art dual energy CT scanner. Proton CT scans were simulated using Monte Carlo methods. The simulations followed the setup used in current prototype proton CT scanners and included realistic modeling of detectors and the corresponding noise characteristics. Stopping power maps were calculated for all three scans, and compared with the ground truth stopping power from the phantoms. Proton CT gave slightly better stopping power estimates than the dual energy CT method, with root mean square errors of 0.2% and 0.5% (for each phantom) compared to 0.5% and 0.9%. Single energy CT root mean square errors were 2.7% and 1.6%. Maximal errors for proton, dual energy and single energy CT were 0.51%, 1.7% and 7.4%, respectively. Better stopping power estimates could significantly reduce the range errors in proton therapy, but requires a large improvement in current methods which may be achievable with proton CT.

  9. Study of the stopping power and straggling for alpha particles and protons in organic solids, liquids and gases

    International Nuclear Information System (INIS)

    Haque, A.K.M.; Mohammadi, A.; Nikjoo, H.

    1985-01-01

    The stopping power and straggling for 5.5 MeV alpha particles in liquid and vapour phases of water, methanol, ethanol, propanol, h-hexane, n-octane and cyclohexane, and those for low energy protons in ethylene, styrene and propylene and their polymers, have been measured. Range-energy data have been fitted with inverse stopping power functions to give the cross sections. In each case, five parameters have been adjusted to obtain the best fit. The value of chi-squared per degree of freedom has been calculated, together with the parameters. The theoretical stopping cross section has been considered employing the Bethe-Bloch expression together with various corrections (shell correction using Walske and Bichsel procedure, Z 1 3 contribution according to Ashley and Bloch correction based on Lindhard formalism). The existence of a phase effect has been clearly demonstrated for the stopping of both alpha particles and protons. (author)

  10. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  11. TU-FG-BRB-03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S; Politte, D; O’Sullivan, J [Washington University in St. Louis, St. Louis, MO (United States); Han, D; Porras-Chaverri, M; Williamson, J [Virginia Commonwealth University, Richmond, VA (United States); Whiting, B [University of Pittsburgh, Pittsburgh, PA (United States)

    2016-06-15

    Purpose: This work aims at reducing the uncertainty in proton stopping power (SP) estimation by a novel combination of a linear, separable basis vector model (BVM) for stopping power calculation (Med Phys 43:600) and a statistical, model-based dual-energy CT (DECT) image reconstruction algorithm (TMI 35:685). The method was applied to experimental data. Methods: BVM assumes the photon attenuation coefficients, electron densities, and mean excitation energies (I-values) of unknown materials can be approximated by a combination of the corresponding quantities of two reference materials. The DECT projection data for a phantom with 5 different known materials was collected on a Philips Brilliance scanner using two scans at 90 kVp and 140 kVp. The line integral alternating minimization (LIAM) algorithm was used to recover the two BVM coefficient images using the measured source spectra. The proton stopping powers are then estimated from the Bethe-Bloch equation using electron densities and I-values derived from the BVM coefficients. The proton stopping powers and proton ranges for the phantom materials estimated via our BVM based DECT method are compared to ICRU reference values and a post-processing DECT analysis (Yang PMB 55:1343) applied to vendorreconstructed images using the Torikoshi parametric fit model (tPFM). Results: For the phantom materials, the average stopping power estimations for 175 MeV protons derived from our method are within 1% of the ICRU reference values (except for Teflon with a 1.48% error), with an average standard deviation of 0.46% over pixels. The resultant proton ranges agree with the reference values within 2 mm. Conclusion: Our principled DECT iterative reconstruction algorithm, incorporating optimal beam hardening and scatter corrections, in conjunction with a simple linear BVM model, achieves more accurate and robust proton stopping power maps than the post-processing, nonlinear tPFM based DECT analysis applied to conventional

  12. Average stopping powers and the use of non-analyte spiking for the determination of phosphorus and sodium by PIPPS

    International Nuclear Information System (INIS)

    Olivier, C.; Morland, H.J.

    1991-01-01

    By using particle induced prompt photon spectrometry, PIPPS, the ratios of the average stopping powers in samples and standards can be used to determine elemental compositions. Since the average stopping powers in the samples are in general unknown, this procedure poses a problem. It has been shown that by spiking the sample with a known amount of a compound with known stopping power and containing a non-analyte element, appropriate stopping powers in the samples can be determined by measuring the prompt gamma-ray yields induced in the spike. Using 5-MeV protons and lithium compounds as non-analyte spikes, sodium and phosphorus were determined in ivory, while sodium was determined in geological samples. For the stopping power determinations in the samples the 429-keV 7 Li n(1,0) and 478-keV 7 Li (1,0) gamma rays were measured, while for phosphorus and sodium determinations the high yield 1,266-keV 31 P (1,0), 440-keV 23 Na (1,0), 1,634-keV, Na 23 α(1,0) and 1,637-keV 23 Na (2,1) gamma rays were used. The method was tested by analyzing the standard reference materials SRM 91, 120c and 694

  13. Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy

    International Nuclear Information System (INIS)

    Scott Ingram, W.; Robertson, Daniel; Beddar, Sam

    2015-01-01

    Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator’s stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent

  14. Interaction of antiprotons with Rb atoms and a comparison of antiproton stopping powers of the atoms H, Li, Na, K, and Rb

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Fischer, Nicolas; Saenz, Alejandro

    2009-01-01

    Ionization and excitation cross sections as well as electron-energy spectra and stopping powers of the alkali metal atoms Li, Na, K, and Rb colliding with antiprotons were calculated using a time-dependent channel-coupling approach. An impact-energy range from 0.25 to 4000 keV was considered....... The target atoms are treated as effective one-electron systems using a model potential. The results are compared with calculated cross sections for antiproton-hydrogen atom collisions....

  15. Mean excitation energies for use in Bethe's stopping-power formula

    International Nuclear Information System (INIS)

    Berger, M.J.; Seltzer, S.M.

    1983-01-01

    A review has been made of the mean excitation energies that can be derived from the analysis of stopping-power and range measurements, and from semi-empirical dipole oscillator-strength distributions for gases and dielectric-response functions for solids. On the basis of this review, mean excitation energies have been selected for 43 elemental substances and 54 compounds. Additivity rules have also been considered which allow one to estimate the mean excitation energies for compounds for which no direct data are available. These additivity rules are based on the use of mean excitation energies for atomic constituents which, to a certain extent, take into account the effects of chemical binding and physical aggregation

  16. Mean excitation energy of polystyrene extracted from proton-stopping-power measurements

    International Nuclear Information System (INIS)

    Porter, L.E.

    1980-01-01

    The measured stopping power of polystyrene for 2.2- to 5.9-MeV protons has been analyzed with the Bloch projectile-z 4 correction term and a modified low-velocity projectile-z 3 term included in the Bethe-Bloch formula. When the full-strength Walske K-shell correction was utilized, the mean excitation energy corresponding to the best fit of the measurements was (71.1 +- 1.8) eV. This result was obtained for a value of the free parameter of the low-velocity projectile-z 3 effect formalism of 1.90 +- 0.05, whether or not a Walske L-shell correction was included

  17. Stopping power for arbitrary angle between test particle velocity and magnetic field

    International Nuclear Information System (INIS)

    Cereceda, Carlo; Peretti, Michel de; Deutsch, Claude

    2005-01-01

    Using the longitudinal dielectric function derived previously for charged test particles in helical movement around magnetic field lines, the numerical convergence of the series involved is found and the double numerical integrations on wave vector components are performed yielding the stopping power for arbitrary angle between the test particle velocity and magnetic field. Calculations are performed for particle Larmor radius larger and shorter than Debye length, i.e., for protons in a cold magnetized plasma and for thermonuclear α particles in a dense, hot, and strongly magnetized plasma. A strong decrease is found for the energy loss as the angle varies from 0 to π/2. The range of thermonuclear α particles as a function of the velocity angle with respect to the magnetic field is also given

  18. On beam quality and stopping power ratios for high-energy x-rays

    International Nuclear Information System (INIS)

    Johnsson, S.A.; Ceberg, C.P.; Knoeoes, T.; Nilsson, P.

    2000-01-01

    The aim of this work is to quantitatively compare two commonly used beam quality indices, TPR(20/10) and %dd(10) x , with respect to their ability to predict stopping power ratios (water to air), s w,air , for high-energy x-rays. In particular, effects due to a varied amount of filtration of the photon beam will be studied. A new method for characterizing beam quality is also presented, where the information we strive to obtain is the moments of the spectral distribution. We will show how the moments enter into a general description of the transmission curve and that it is possible to correlate the moments to s w,air with a unique and simple relationship. Comparisons with TPR(20/10) and %dd(10) x show that the moments are well suited for beam quality specification in terms of choosing the correct s w,air . (author)

  19. Reliability of Power Electronic Converter Systems

    DEFF Research Database (Denmark)

    -link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault...... for advancing the reliability, availability, system robustness, and maintainability of PECS at different levels of complexity. Drawing on the experience of an international team of experts, this book explores the reliability of PECS covering topics including an introduction to reliability engineering in power...... electronic converter systems; anomaly detection and remaining-life prediction for power electronics; reliability of DC-link capacitors in power electronic converters; reliability of power electronics packaging; modeling for life-time prediction of power semiconductor modules; minimization of DC...

  20. The stopping power and energy straggling of the energetic C and O ions in polyimide

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v.i, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Macková, A. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v.i, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2016-03-15

    The stopping power and energy straggling of {sup 12}C{sup n+} and {sup 16}O{sup n+} heavy ions in the energy range 5.3–8.0 MeV in 8 μm thick polyimide (PI) foil were measured by means of an indirect transmission method using a half-covered a PIPS detector. Ions scattered from thin gold layer, under the scattering angle 150° were detected and the spectrum of ions penetrating the PI foil and without foil was recorded. The values of the experimentally determined stopping powers were compared to the calculated data by SRIM-2013 and MSTAR codes. Measured data were in good agreement with data calculated by SRIM-2013, especially for C ions was observed better agreement than for O ions. The energy straggling was determined and compared to those calculated by using Bohr’s, Bethe–Livingston and Yang models. The measured energy straggling values in the PI foil was corrected for foil roughness and thickness inhomogeneity determined from AFM. Bethe–Livingston predicting formula has been modified to make it appropriate for thicker targets. The energy straggling determined in our experiment was obtained higher than Bohr’s predicted value; the predictions by Yang are in good agreement with our experiment. Bethe–Livingston formulation of the energy straggling shows better agreement with the experimental data after the modified formula implementation which assumes that the thick target was consisted to be composed of n-number of thin layers. Influence of the charge-exchange phenomena to the energy straggling of C and O ions in PI was discussed.

  1. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding...

  2. Molecular dynamics with phase-shift-based electronic stopping for calibration of ion implantation profiles in crystalline silicon

    International Nuclear Information System (INIS)

    Chan, H.Y.; Nordlund, K.; Gossmann, H.-J.L.; Harris, M.; Montgomery, N.J.; Mulcahy, C.P.A.; Biswas, S.; Srinivasan, M.P.; Benistant, F.; Ng, C.M.; Chan, Lap

    2006-01-01

    Prediction of the final dopant positions after ion implantation has always been strongly influenced by the choice of stopping models. A molecular dynamics (MD) method is used in this work; the nuclear stopping is treated by accurate pair potentials calculated by density functional theory (DFT). The slowing down due to collisions with electrons will be described by both a non-local semi-empirical model and a local model based on Fermi level phase shift factors. Comparisons with experimental data using both models show that a local pair-specific electronic stopping model is essential in accurately predicting range profiles for any element even at low implant energies where nuclear effects are dominant

  3. Power Minimization through Packet Retention in Cognitive Radio Sensor Networks under Interference and Delay Constraints: An Optimal Stopping Approach

    Directory of Open Access Journals (Sweden)

    Amr Y. Elnakeeb

    2016-04-01

    Full Text Available The aim of this article is twofold: First, we study the problem of packets retention in a queue with the aim of minimizing transmission power in delay-tolerant applications. The problem is classified as an optimal stopping problem. The optimal stopping rule has been derived as well. Optimal number of released packets is determined in each round through an Integer Linear Programming (ILP optimization problem. This transmission paradigm is tested via simulations in an interference-free environment leading to a significant reduction in transmission power (at least 55%. Second, we address the problem of applying the scheme of packets retention through the Optimal Stopping Policy (OSP to underlay Cognitive Radio Sensor Networks (CRSNs where strict interference threshold does exist. Simulations proved that our scheme outperforms traditional transmission method as far as dropped packet rate and Average Power per Transmitted Packet (APTP are concerned.

  4. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark

    DEFF Research Database (Denmark)

    Hansen, David Christoffer; Seco, Joao; Sørensen, Thomas Sangild

    2015-01-01

    Background. Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in...... development) have both been proposed as methods for obtaining patient stopping power maps. The purpose of this work was to assess the accuracy of proton CT using dual energy CT scans of phantoms to establish reference accuracy levels. Material and methods. A CT calibration phantom and an abdomen cross section...... phantom containing inserts were scanned with dual energy and single energy CT with a state-of-the-art dual energy CT scanner. Proton CT scans were simulated using Monte Carlo methods. The simulations followed the setup used in current prototype proton CT scanners and included realistic modeling...

  5. Power Electronics and Electric Machines Publications | Transportation

    Science.gov (United States)

    Research | NREL and Electric Machines Publications Power Electronics and Electric Machines Publications NREL and its partners have produced many papers and presentations related to power electronics and from power electronics and electric machines research are available to the public. Photo by Pat Corkery

  6. Partial and total electronic stopping cross sections of atoms for a singly charged helium ion, Part 2

    International Nuclear Information System (INIS)

    Kaneko, T.; Nishikori, M.; Yamato, N.

    1991-08-01

    Partial and total electronic stopping cross sections of atoms with Z (55 ≤ Z ≤ 92) for a He + ion are tabulated as the second part of NIFS-DATA-11 (1991) on the basis of the wave-packet theory. (author)

  7. Self-Powered, One-Stop, and Multifunctional Implantable Triboelectric Active Sensor for Real-Time Biomedical Monitoring.

    Science.gov (United States)

    Ma, Ye; Zheng, Qiang; Liu, Yang; Shi, Bojin; Xue, Xiang; Ji, Weiping; Liu, Zhuo; Jin, Yiming; Zou, Yang; An, Zhao; Zhang, Wei; Wang, Xinxin; Jiang, Wen; Xu, Zhiyun; Wang, Zhong Lin; Li, Zhou; Zhang, Hao

    2016-10-12

    Operation time of implantable electronic devices is largely constrained by the lifetime of batteries, which have to be replaced periodically by surgical procedures once exhausted, causing physical and mental suffering to patients and increasing healthcare costs. Besides the efficient scavenging of the mechanical energy of internal organs, this study proposes a self-powered, flexible, and one-stop implantable triboelectric active sensor (iTEAS) that can provide continuous monitoring of multiple physiological and pathological signs. As demonstrated in human-scale animals, the device can monitor heart rates, reaching an accuracy of ∼99%. Cardiac arrhythmias such as atrial fibrillation and ventricular premature contraction can be detected in real-time. Furthermore, a novel method of monitoring respiratory rates and phases is established by analyzing variations of the output peaks of the iTEAS. Blood pressure can be independently estimated and the velocity of blood flow calculated with the aid of a separate arterial pressure catheter. With the core-shell packaging strategy, monitoring functionality remains excellent during 72 h after closure of the chest. The in vivo biocompatibility of the device is examined after 2 weeks of implantation, proving suitability for practical use. As a multifunctional biomedical monitor that is exempt from needing an external power supply, the proposed iTEAS holds great potential in the future of the healthcare industry.

  8. Quiet: The Power of Introvert in a World That Can’t Stop Talking

    Directory of Open Access Journals (Sweden)

    Sean Schat

    2012-11-01

    Full Text Available Do you pay attention to the differences between extroversion and introversion? It can be fascinating to consider who is and is not aware of  the distinction between the two, as well as the significant formative role they both play in daily perceptions and interactions.  In my experience, more often than not it is the introverts who recognize and appreciate the difference, while too many extroverts remain unaware. In  Quiet: The Power of Introverts in a World That Can’t Stop Talking(2012, Susan Cain reminds us of the potency and power of the gift of introversion.  She challenges her readers to recognize and celebrate the unique insights and contributions that may be latent in communities and organizations—present, but hidden from view, and likely to remain so unless given the space to flourish and to find a voice. She also suggests that creating a space for the introvert voice may bring unforeseen blessings to an organization or community.

  9. A study of charge state approach to the stopping power of MeV B, N, and O ions in carbon

    International Nuclear Information System (INIS)

    Li, M.M.; O'Connor, D.J.; Timmers, H.; Dastoor, P.C.

    1999-01-01

    The charge state approach has been applied to treat the electronic stopping powers of swift O, N and B ions in carbon foil. According to the charge state model, the contributions to the electronic stopping power of energetic projectiles passing through solid targets are due to collisional interactions and from the charge exchange process. The definition of fractional effective charge from Brandt and Kitagawa has been combined into the current charge state model. Extensive applications of this approach require data of the equilibrium charge state distributions and knowledge of charge-exchange cross sections-involving electronic capture and loss processes. Both measured data and empirical calculations of the equilibrium charge state fraction are used in the study, and the electronic capture cross sections are obtained with the eikonal Brinkman-Kramers approximation (EBK). By comparing the numerical results with the latest experimental data as well as empirical values, it is shown that the present approach slightly overestimates the energy loss at the intermediate velocity region

  10. Material discrimination using scattering and stopping of cosmic ray muons and electrons: Differentiating heavier from lighter metals as well as low-atomic weight materials

    Science.gov (United States)

    Blanpied, Gary; Kumar, Sankaran; Dorroh, Dustin; Morgan, Craig; Blanpied, Isabelle; Sossong, Michael; McKenney, Shawn; Nelson, Beth

    2015-06-01

    Reported is a new method to apply cosmic-ray tomography in a manner that can detect and characterize not only dense assemblages of heavy nuclei (like Special Nuclear Materials, SNM) but also assemblages of medium- and light-atomic-mass materials (such as metal parts, conventional explosives, and organic materials). Characterization may enable discrimination between permitted contents in commerce and contraband (explosives, illegal drugs, and the like). Our Multi-Mode Passive Detection System (MMPDS) relies primarily on the muon component of cosmic rays to interrogate Volumes of Interest (VOI). Muons, highly energetic and massive, pass essentially un-scattered through materials of light atomic mass and are only weakly scattered by conventional metals used in industry. Substantial scattering and absorption only occur when muons encounter sufficient thicknesses of heavy elements characteristic of lead and SNM. Electrons are appreciably scattered by light elements and stopped by sufficient thicknesses of materials containing medium-atomic-mass elements (mostly metals). Data include simulations based upon GEANT and measurements in the HMT (Half Muon Tracker) detector in Poway, CA and a package scanner in both Poway and Socorro NM. A key aspect of the present work is development of a useful parameter, designated the "stopping power" of a sample. The low-density regime, comprising organic materials up to aluminum, is characterized using very little scattering but a strong variation in stopping power. The medium-to-high density regime shows a larger variation in scattering than in stopping power. The detection of emitted gamma rays is another useful signature of some materials.

  11. Atomic stopping-power problems encountered in measurements of nuclear γ-ray lifetimes by the Doppler-shift-attenuation method

    International Nuclear Information System (INIS)

    Latta, B.M.; Scanlon, P.J.

    1976-01-01

    The value of the nuclear lifetime of the 3.34-MeV level in 22 Ne as determined by Broude et al. by the Doppler shift attenuation method exhibits variations depending on the atomic number Z 2 of the slowing down medium. The lifetime has been re-evaluated within the framework of the Lindhard-Winther stopping theory, assuming a simple approximate form for the density of electrons associated with an atom in a solid and an effective point charge for the projectile based on experimental stopping powers. Although there are still variations in the value of the lifetime the variations appear to be systematic through the region of the transition elements. (Auth.)

  12. Power electronics for renewable energy systems

    DEFF Research Database (Denmark)

    Iov, Florin; Blaabjerg, Frede

    2009-01-01

    sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss some of the most emerging renewable energy sources......, wind energy and photovoltaics, which by means of power electronics are changing from being minor energy sources to be acting as important power sources in the energy system....

  13. Stopping power of charged particles from 10 eV/amu to 10 GeV/amu

    International Nuclear Information System (INIS)

    Nakane, Yoshihiro; Tanaka, Shun-ichi; Furihata, Shiori; Iwai, Satoshi.

    1993-08-01

    Electric collision, nuclear collision and total stopping powers in 10 kinds of elements: H 2 , He, Be, C, Al, Fe, Cu, W, Pb and U, and 4 kinds of materials: water, phantom, LiF-TLD and SSNTD (solid state neutron track detector) have been calculated for 10 kinds of charged particles from 10 eV/amu to 10 GeV/amu with STOPPING, SPAR, and RSTAN/RSHEV codes, in which the charged particles are important projectiles for evaluating the dose and detector responses of radiations, and for accelerator shielding calculations. Calculated data are presented in Table and Figure. (author)

  14. Experimental study of stopping powers for ions of intermediate atomic numbers

    International Nuclear Information System (INIS)

    Bucher, R.G.

    1975-01-01

    A technique has been developed to measure the energy loss as a function of ion atomic number for the fragments emitted by the spontaneous fission of 252 Cf; the atomic numbers of the fragments were directly measured by the detection of a characteristic K x-ray. The measured energy losses were compared with the theories of Lindhard and of Firsov, with the tabulation of Northcliffe and Schilling, and with the semiempirical formula of Moak and Brown. For the light fragments the measured values are in good agreement with the predictions of Moak--Brown and Northcliffe--Schilling; for the heavy fragments the measured values are approximately midway between the prediction of Moak--Brown and Northcliffe--Schilling and those of Lindhard for xi/sub epsilon/ = 2. The difference in the stopping powers for adjacent ion atomic numbers Z 1 was concluded to be (1.8 +- 0.2) percent for 40 less than or equal to Z 1 less than or equal to 45 at a velocity of 1.36 cm/ns and (2.0 +- 0.1) percent for 53 less than or equal to Z 1 less than or equal to 58 at a velocity of 1.04 cm/ns

  15. Material discrimination using scattering and stopping of cosmic ray muons and electrons: Differentiating heavier from lighter metals as well as low-atomic weight materials

    Energy Technology Data Exchange (ETDEWEB)

    Blanpied, Gary; Kumar, Sankaran; Dorroh, Dustin; Morgan, Craig; Blanpied, Isabelle; Sossong, Michael; McKenney, Shawn; Nelson, Beth

    2015-06-01

    Reported is a new method to apply cosmic-ray tomography in a manner that can detect and characterize not only dense assemblages of heavy nuclei (like Special Nuclear Materials, SNM) but also assemblages of medium- and light-atomic-mass materials (such as metal parts, conventional explosives, and organic materials). Characterization may enable discrimination between permitted contents in commerce and contraband (explosives, illegal drugs, and the like). Our Multi-Mode Passive Detection System (MMPDS) relies primarily on the muon component of cosmic rays to interrogate Volumes of Interest (VOI). Muons, highly energetic and massive, pass essentially un-scattered through materials of light atomic mass and are only weakly scattered by conventional metals used in industry. Substantial scattering and absorption only occur when muons encounter sufficient thicknesses of heavy elements characteristic of lead and SNM. Electrons are appreciably scattered by light elements and stopped by sufficient thicknesses of materials containing medium-atomic-mass elements (mostly metals). Data include simulations based upon GEANT and measurements in the HMT (Half Muon Tracker) detector in Poway, CA and a package scanner in both Poway and Socorro NM. A key aspect of the present work is development of a useful parameter, designated the “stopping power” of a sample. The low-density regime, comprising organic materials up to aluminum, is characterized using very little scattering but a strong variation in stopping power. The medium-to-high density regime shows a larger variation in scattering than in stopping power. The detection of emitted gamma rays is another useful signature of some materials.

  16. Power Electronics Control of Wind Energy in Distributed Power System

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

  17. Design for Reliability of Power Electronic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Sangwongwanich, Ariya

    2018-01-01

    Power density, efficiency, cost, and reliability are the major challenges when designing a power electronic system. Latest advancements in power semiconductor devices (e.g., silicon carbide devices) and topological innovations have vital contributions to power density and efficiency. Nevertheless......, dedicated heat sink systems for thermal management are required to dissipate the power losses in power electronic systems; otherwise, the power devices will be heated up and eventually fail to operate. In addition, in many mission critical applications (e.g., marine systems), the operating condition (i...

  18. Power Electronics in Wind Turbine Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe; Teodorescu, Remus

    2006-01-01

    the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power systems, power production and end-user application. This paper discuss the most emerging renewable energy source, wind energy, which by means of power...... electronics is changing from being a minor energy source to be acting as an important power source in the energy system. By that wind power is also getting an added value in the power system operation....

  19. Handbook of power systems engineering with power electronics applications

    CERN Document Server

    Hase, Yoshihide

    2012-01-01

    Formerly known as Handbook of Power System Engineering, this second edition provides rigorous revisions to the original treatment of systems analysis together with a substantial new four-chapter section on power electronics applications. Encompassing a whole range of equipment, phenomena, and analytical approaches, this handbook offers a complete overview of power systems and their power electronics applications, and presents a thorough examination of the fundamental principles, combining theories and technologies that are usually treated in separate specialised fields, in a single u

  20. Stopping powers of Zr, Pd, Cd, In and Pb for 6.5 MeV protons and mean excitation energies

    International Nuclear Information System (INIS)

    Ishiwari, R.; Shiomi, N.; Sakamoto, N.

    1983-01-01

    Stopping powers of Zr, Pd, Cd, In and Pb have been measured for 6.5 MeV protons. Mean excitation energies have been extracted from the stopping power data by taking into account Bloch correction and Z 1 3 correction. For the shell correction the Bonderup shell correction has been used. The results agree fairly well with those of other authors

  1. Design for Reliability of Power Electronic Systems

    DEFF Research Database (Denmark)

    Wang, Huai; Ma, Ke; Blaabjerg, Frede

    2012-01-01

    Advances in power electronics enable efficient and flexible processing of electric power in the application of renewable energy sources, electric vehicles, adjustable-speed drives, etc. More and more efforts are devoted to better power electronic systems in terms of reliability to ensure high......). A collection of methodologies based on Physics-of-Failure (PoF) approach and mission profile analysis are presented in this paper to perform reliability-oriented design of power electronic systems. The corresponding design procedures and reliability prediction models are provided. Further on, a case study...... on a 2.3 MW wind power converter is discussed with emphasis on the reliability critical components IGBTs. Different aspects of improving the reliability of the power converter are mapped. Finally, the challenges and opportunities to achieve more reliable power electronic systems are addressed....

  2. SU-E-J-149: Secondary Emission Detection for Improved Proton Relative Stopping Power Identification

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, J; Musall, B; Erickson, A [Georgia Institute of Technology, Atlanta, GA (Georgia)

    2015-06-15

    Purpose: This research investigates application of secondary prompt gamma (PG) emission spectra, resulting from nuclear reactions induced by protons, to characterize tissue composition along the particle path. The objective of utilizing the intensity of discrete high-energy peaks of PG is to improve the accuracy of relative stopping power (RSP) values available for proton therapy treatment planning on a patient specific basis and to reduce uncertainty in dose depth calculations. Methods: In this research, MCNP6 was used to simulate PG emission spectra generated from proton induced nuclear reactions in medium of varying composition of carbon, oxygen, calcium and nitrogen, the predominant elements found in human tissue. The relative peak intensities at discrete energies predicted by MCNP6 were compared to the corresponding atomic composition of the medium. Results: The results have shown a good general agreement with experimentally measured values reported by other investigators. Unexpected divergence from experimental spectra was noted in the peak intensities for some cases depending on the source of the cross-section data when using compiled proton table libraries vs. physics models built into MCNP6. While the use of proton cross-section libraries is generally recommended when available, these libraries lack data for several less abundant isotopes. This limits the range of their applicability and forces the simulations to rely on physics models for reactions with natural atomic compositions. Conclusion: Current end-of-range proton imaging provides an average RSP for the total estimated track length. The accurate identification of tissue composition along the incident particle path using PG detection and characterization allows for improved determination of the tissue RSP on the local level. While this would allow for more accurate depth calculations resulting in tighter treatment margins, precise understanding of proton beam behavior in tissue of various

  3. Measurement of the stopping power of water for carbon ions in the energy range of 1 MeV-6 MeV using the inverted Doppler-shift attenuation method

    Energy Technology Data Exchange (ETDEWEB)

    Rahm, Johannes Martin

    2016-10-31

    Cancer therapy using carbon ions has gained increasing interest in the last decade due to its advantageous dose distributions. For the dosimetry and treatment planning, the accurate knowledge of the stopping power of water for carbon ions is of crucial importance. In the high energy region, the stopping power can be calculated rather accurately by means of the Bethe-Bloch formula. In the case of projectile velocities comparable to those of the valence electrons of the target, these calculations are subject to large uncertainties. There exist no experimental data for the stopping power of water for projectile energies prevailing in the so-called Bragg peak region. The currently available stopping power data for water are derived from measurements in water vapour or D{sub 2}O ice and, hence, neglect the dependence on the state of aggregation. The stopping power of water for charged particles is of high interest not only for practical applications but also to consider how physical and chemical state of the target influence the collisional energy transfer. For the measurement of the stopping power of water, the inverted Doppler-shift attenuation method was used in this work. This method has the advantage that the projectile itself is not needed to be detected and can be slowed down entirely in the target. In this method, the stopping power is determined from the Doppler-shift of the gamma-quanta emitted by projectiles during their slow down. This experiment can be performed at atmospheric pressure and consequently, the stopping power of water can be measured in its real physiological condition. In this work, the stopping power of water for carbon ions was measured for the first time in the energy range between 1 MeV and 6 MeV covering the kinetic energies of carbon ions in the Bragg peak region. The experimental method is presented in detail along with the design of the apparatus and of the data acquisition system. A comprehensive analysis of instrumental effects

  4. Experience with spice teaching power electronics

    DEFF Research Database (Denmark)

    Munk-Nielsen, Stig

    2009-01-01

    A free Spice version allowing general circuit simulation is used teaching power electronics. There is no lock on the circuit size, stabile and user friendly operation is experienced. A collection of transformer, converter and drive system models are implemented to investigate the usability...... of the programme in high power electronics....

  5. Power electronics substrate for direct substrate cooling

    Science.gov (United States)

    Le, Khiet [Mission Viejo, CA; Ward, Terence G [Redondo Beach, CA; Mann, Brooks S [Redondo Beach, CA; Yankoski, Edward P [Corona, CA; Smith, Gregory S [Woodland Hills, CA

    2012-05-01

    Systems and apparatus are provided for power electronics substrates adapted for direct substrate cooling. A power electronics substrate comprises a first surface configured to have electrical circuitry disposed thereon, a second surface, and a plurality of physical features on the second surface. The physical features are configured to promote a turbulent boundary layer in a coolant impinged upon the second surface.

  6. Editorial for IEEE Transactions on Power Electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede

    2007-01-01

    Our IEEE transactions on power electronics has had some very positive progress these past years under the leadership of Dr. Daan van Wyk. Papers have been processed efficiently both in review time and publication time. This success has spread throughout the whole power electronics community which...

  7. Stopping powers from the inverted doppler shift attenuation method: Z-oscillations; Bragg's rule or chemical effects; solid and liquid state effects

    International Nuclear Information System (INIS)

    Pietsch, W.; Hauser, U.; Neuwirth, W.

    1976-01-01

    With the 'Inverted Doppler Shift Attenuation (IDSA)' method stopping cross sections for swift ions can be measured with an accuracy of about 1%. Here results are reported with lithium and carbon projectiles in very different stopping materials. It turns out that the stopping cross section around Bohr's velocity is linearly dependent on the velocity. Stopping cross sections of elements show the expected Z 2 -oscillations. With compound targets strong deviations from Bragg's rule were found which means that the stopping cross section is influenced by the chemical bonding. In electrolytic solutions effects due to ion-dipole interactions can be observed. These phenomena demonstrate the strong sensitivity of electronic stopping cross sections on the specific distribution of the outer electrons of the target atoms. Further Lindhard's formula has been modified which gives a good description of this influence. (Auth.)

  8. Power electronics handbook components, circuits and applications

    CERN Document Server

    Mazda, F F

    1993-01-01

    Power Electronics Handbook: Components, Circuits, and Applications is a collection of materials about power components, circuit design, and applications. Presented in a practical form, theoretical information is given as formulae. The book is divided into three parts. Part 1 deals with the usual components found in power electronics such as semiconductor devices and power semiconductor control components, their electronic compatibility, and protection. Part 2 tackles parts and principles related to circuits such as switches; link frequency chargers; converters; and AC line control, and Part 3

  9. The selection of stopping power and mass energy absorption coefficient data for the HPA Code of Practice for dosimetry

    International Nuclear Information System (INIS)

    Williams, P.C.

    1985-01-01

    The author draws attention to a discussion by Cunningham and Schultz (1984) which states that, 'with the exception of the NACP and AAPM protocols, the selection of stopping power and energy absorption coefficient ratios has been based upon only the stated accelerating potential of the accelerator', and points out that the HPA Revised Code of Practice should be added to these exceptions. In calculating the HPA's new Csub(lambda) values, a similar, but not identical, approach was taken in order to determine the stopping power and absorption coefficient ratios at each radiation quality. It was recognised that the approximation of a spectrum to a monoenergetic spectrum of between 0.4 and 0.45 of the maximum energy, as had been done in calculating the values, given in ICRU Report 14, was incorrect. (U.K.)

  10. Theoretical studies on the stopping power of deuterium-tritium mixed with uranium plasmas for α particles

    International Nuclear Information System (INIS)

    Wang, Zhigang; Fu, Zhen-Guo; Zhang, Ping

    2014-01-01

    The stopping power of a compressed and highly ionized deuterium-tritium (DT) and uranium (U) plasma for α particles at very high temperatures (T = 5 keV) is examined theoretically with the dimensional continuation method. We show that with increasing density of U, both the magnitude and width of the resonance peak in the stopping power (as a function of the α particle energy), increases because of the ions, while the penetration distance of the α particles decreases. A simple relation of decreasing penetration distance as a function of plasma density is observed, which may be useful for inertial confinement fusion experiments. Moreover, by comparing the results with the case of a DT plasma mixed with beryllium, we find that the effect of a higher Z plasma is stronger, with regard to energy loss as well as the penetration distance of α particles, than that of a lower Z plasma

  11. Calculation of the protons stopping power in water using dielectric formalism in the MELF-GOS approach

    International Nuclear Information System (INIS)

    Ribeiro, Franciane; Mazer, Amanda Cristina; Hormaza, Joel Mesa

    2016-01-01

    In order to calculate the stopping power of protons, there are many very successful models at high energies, which are extrapolated to low-energy regions. From the point of view of application of proton beam in cancer treatment is just this low energy region the most relevant due to the dose deposition profile in depth for protons. In this work, we present a calculation of the stopping power of protons in a water target using the dielectric formalism in MELF-GOS approach. The results when compared to other models show good agreement for energies above 100 keV and lower values below this energy. This result should impact the range of values of protons and the Bragg peak position. (author)

  12. Electron irradiation of power transistors

    International Nuclear Information System (INIS)

    Hower, P.L.; Fiedor, R.J.

    1982-01-01

    A method for reducing storage time and gain parameters in a semiconductor transistor includes the step of subjecting the transistor to electron irradiation of a dosage determined from measurements of the parameters of a test batch of transistors. Reduction of carrier lifetime by proton bombardment and gold doping is mentioned as an alternative to electron irradiation. (author)

  13. Studies of endothelial monolayer formation on irradiated poly-L-lactide acid with ions of different stopping power and velocity

    Energy Technology Data Exchange (ETDEWEB)

    Arbeitman, Claudia R. [CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Gerencia de Investigación y Aplicaciones, TANDAR-CNEA (Argentina); UNQ – IMBICE – CCT – CONICET – LA PLATA (Argentina); Grosso, Mariela F. del [CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Gerencia de Investigación y Aplicaciones, TANDAR-CNEA (Argentina); Ibañez, Irene L. [CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Behar, Moni [Instituto de Física, UFRGS, Porto Alegre, RS (Brazil); Grasselli, Mariano [UNQ – IMBICE – CCT – CONICET – LA PLATA (Argentina); Bermúdez, Gerardo García [Gerencia de Investigación y Aplicaciones, TANDAR-CNEA (Argentina)

    2015-12-15

    In this work we study cell viability, proliferation and morphology of bovine aortic endothelial cells (BAEC) cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. In a previous study comparing ions beams with the same stopping power we observed an increase in cell density and a better cell morphology at higher ion velocities. In the present work we continued this study using heavy ions beam with different stopping power and ion velocities. To this end thin films of 50 μm thickness were irradiated with 2 MeV/u and 0.10 MeV/u ion beams provided the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The results suggest that a more dense and elongated cell shapes, similar to the BAEC cells on the internal surface of bovine aorta, was obtained for stopping power of 18.2–22.1 MeV cm{sup 2} mg{sup −1} and ion velocity of 2 MeV/u. On the other hand, for low ion velocity 0.10 MeV/u the cells present a more globular shapes.

  14. Studies of endothelial monolayer formation on irradiated poly-L-lactide acid with ions of different stopping power and velocity

    International Nuclear Information System (INIS)

    Arbeitman, Claudia R.; Grosso, Mariela F. del; Ibañez, Irene L.; Behar, Moni; Grasselli, Mariano; Bermúdez, Gerardo García

    2015-01-01

    In this work we study cell viability, proliferation and morphology of bovine aortic endothelial cells (BAEC) cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. In a previous study comparing ions beams with the same stopping power we observed an increase in cell density and a better cell morphology at higher ion velocities. In the present work we continued this study using heavy ions beam with different stopping power and ion velocities. To this end thin films of 50 μm thickness were irradiated with 2 MeV/u and 0.10 MeV/u ion beams provided the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The results suggest that a more dense and elongated cell shapes, similar to the BAEC cells on the internal surface of bovine aorta, was obtained for stopping power of 18.2–22.1 MeV cm 2 mg −1 and ion velocity of 2 MeV/u. On the other hand, for low ion velocity 0.10 MeV/u the cells present a more globular shapes.

  15. High fluence effects on ion implantation stopping and range

    International Nuclear Information System (INIS)

    Selvi, S.; Tek, Z.; Oeztarhan, A.; Akbas, N.; Brown, I.G.

    2005-01-01

    We have developed a code STOPPO which can be used to modify the more-widely used ion implantation codes to more accurately predict the mean nuclear and electronic stopping power, preferential sputtering and range of heavy ions in monatomic target materials. In our simulations an effective atomic number and effective atomic mass are introduced into conveniently available analytical stopping cross-sections and a better fitting function for preferential sputtering yield is carefully evaluated for each ion implantation. The accuracy of the code confirmed experimentally by comparison with measured Rutherford backscattering spectrometry (RBS) concentration profiles for 130 keV Zr ions implanted into Be to fluences of 1 x 10 17 , 2 x 10 17 and 4 x 10 17 ions/cm 2 . We find a steady increase in the mean nuclear and electronic stopping powers of the target; the increase in nuclear stopping power is much greater than the increase in electronic stopping power

  16. Technical Note: On the calculation of stopping-power ratio for stoichiometric calibration in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ödén, Jakob [Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176, Sweden and Department of Medical Radiation Physics, Stockholm University and Karolinska Institutet, Stockholm SE-17176 (Sweden); Zimmerman, Jens; Nowik, Patrik; Poludniowski, Gavin, E-mail: gavin.poludniowski@karolinska.se [Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176 (Sweden); Bujila, Robert [Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176, Sweden and Department of Physics, Royal Institute of Technology, Stockholm SE-10691 (Sweden)

    2015-09-15

    Purpose: The quantitative effects of assumptions made in the calculation of stopping-power ratios (SPRs) are investigated, for stoichiometric CT calibration in proton therapy. The assumptions investigated include the use of the Bethe formula without correction terms, Bragg additivity, the choice of I-value for water, and the data source for elemental I-values. Methods: The predictions of the Bethe formula for SPR (no correction terms) were validated against more sophisticated calculations using the SRIM software package for 72 human tissues. A stoichiometric calibration was then performed at our hospital. SPR was calculated for the human tissues using either the assumption of simple Bragg additivity or the Seltzer-Berger rule (as used in ICRU Reports 37 and 49). In each case, the calculation was performed twice: First, by assuming the I-value of water was an experimentally based value of 78 eV (value proposed in Errata and Addenda for ICRU Report 73) and second, by recalculating the I-value theoretically. The discrepancy between predictions using ICRU elemental I-values and the commonly used tables of Janni was also investigated. Results: Errors due to neglecting the correction terms to the Bethe formula were calculated at less than 0.1% for biological tissues. Discrepancies greater than 1%, however, were estimated due to departures from simple Bragg additivity when a fixed I-value for water was imposed. When the I-value for water was calculated in a consistent manner to that for tissue, this disagreement was substantially reduced. The difference between SPR predictions when using Janni’s or ICRU tables for I-values was up to 1.6%. Experimental data used for materials of relevance to proton therapy suggest that the ICRU-derived values provide somewhat more accurate results (root-mean-square-error: 0.8% versus 1.6%). Conclusions: The conclusions from this study are that (1) the Bethe formula can be safely used for SPR calculations without correction terms; (2

  17. Technical Note: On the calculation of stopping-power ratio for stoichiometric calibration in proton therapy

    International Nuclear Information System (INIS)

    Ödén, Jakob; Zimmerman, Jens; Nowik, Patrik; Poludniowski, Gavin; Bujila, Robert

    2015-01-01

    Purpose: The quantitative effects of assumptions made in the calculation of stopping-power ratios (SPRs) are investigated, for stoichiometric CT calibration in proton therapy. The assumptions investigated include the use of the Bethe formula without correction terms, Bragg additivity, the choice of I-value for water, and the data source for elemental I-values. Methods: The predictions of the Bethe formula for SPR (no correction terms) were validated against more sophisticated calculations using the SRIM software package for 72 human tissues. A stoichiometric calibration was then performed at our hospital. SPR was calculated for the human tissues using either the assumption of simple Bragg additivity or the Seltzer-Berger rule (as used in ICRU Reports 37 and 49). In each case, the calculation was performed twice: First, by assuming the I-value of water was an experimentally based value of 78 eV (value proposed in Errata and Addenda for ICRU Report 73) and second, by recalculating the I-value theoretically. The discrepancy between predictions using ICRU elemental I-values and the commonly used tables of Janni was also investigated. Results: Errors due to neglecting the correction terms to the Bethe formula were calculated at less than 0.1% for biological tissues. Discrepancies greater than 1%, however, were estimated due to departures from simple Bragg additivity when a fixed I-value for water was imposed. When the I-value for water was calculated in a consistent manner to that for tissue, this disagreement was substantially reduced. The difference between SPR predictions when using Janni’s or ICRU tables for I-values was up to 1.6%. Experimental data used for materials of relevance to proton therapy suggest that the ICRU-derived values provide somewhat more accurate results (root-mean-square-error: 0.8% versus 1.6%). Conclusions: The conclusions from this study are that (1) the Bethe formula can be safely used for SPR calculations without correction terms; (2

  18. Digital simulation of power electronic systems

    International Nuclear Information System (INIS)

    Mehring, P.; Jentsch, W.; John, G.; Kraemer, D.

    1981-01-01

    The following paper contains the final report on the NETSIM-Project. The purpose of this project is to develop a special digital simulation system, which could serve as a base for routine application of simulation in planning and development of power electronic systems. The project is realized in two steps. First a basic network analysis system is established. With this system the basic models and methods in treating power electronic networks could be probed. The resulting system is then integrated into a general digital simulation system for continous systems (CSSL-System). This integrated simulation system allows for convenient modeling and simulation of power electronic systems. (orig.) [de

  19. Reliability of power electronic converter systems

    CERN Document Server

    Chung, Henry Shu-hung; Blaabjerg, Frede; Pecht, Michael

    2016-01-01

    This book outlines current research into the scientific modeling, experimentation, and remedial measures for advancing the reliability, availability, system robustness, and maintainability of Power Electronic Converter Systems (PECS) at different levels of complexity.

  20. Comprehensive Power Losses Model for Electronic Power Transformer

    DEFF Research Database (Denmark)

    Yue, Quanyou; Li, Canbing; Cao, Yijia

    2018-01-01

    and considering the impact of the non-unity power factor and the three-phase unbalanced current, the overall power losses in the distribution network when using the EPT to replace the conventional transformer is analyzed, and the conditions in which the application of the EPT can cause less power losses...... reduced power losses in the distribution network require a comprehensive consideration when comparing the power losses of theEPT and conventional transformer. In this paper, a comprehensive power losses analysis model for the EPT in distribution networks is proposed. By analyzing the EPT self-losses......The electronic power transformer (EPT) has highe rpower losses than the conventional transformer. However, the EPT can correct the power factor, compensate the unbalanced current and reduce the line power losses in the distribution network.Therefore, the higher losses of the EPT and the consequent...

  1. Comprehensive Power Losses Model for Electronic Power Transformer

    DEFF Research Database (Denmark)

    Yue, Quanyou; Li, Canbing; Cao, Yijia

    2018-01-01

    The electronic power transformer (EPT) has highe rpower losses than the conventional transformer. However, the EPT can correct the power factor, compensate the unbalanced current and reduce the line power losses in the distribution network.Therefore, the higher losses of the EPT and the consequent...... reduced power losses in the distribution network require a comprehensive consideration when comparing the power losses of theEPT and conventional transformer. In this paper, a comprehensive power losses analysis model for the EPT in distribution networks is proposed. By analyzing the EPT self......-losses and considering the impact of the non-unity power factor and the three-phase unbalanced current, the overall power losses in the distribution network when using the EPT to replace the conventional transformer is analyzed, and the conditions in which the application of the EPT can cause less power losses...

  2. CSDA range, stopping power and mean penetration depth energy relationships in some hydrocarbons and biologic materials for 10 eV to 100 MeV with the modified Rohrlich-Carlson model

    Energy Technology Data Exchange (ETDEWEB)

    Guemues, Hasan [Ondokuz Mayis University, Department of Physics, Faculty of Sciences and Arts, Samsun (Turkey); Bentabet, Abdelouahab [Bordj Bou Arreridj University, LCVRN, SNVSTU Faculty, El Anasser (Algeria)

    2017-05-15

    In this study, for some hydrocarbons and biological compounds, stopping power formula are presented, being valid for low and intermediate electron energies. In addition, calculation of the continuous slowing down approximation range (CSDA range) from the stopping power is also made. Calculation of the CSDA range for some hydrocarbons: C{sub 2}H{sub 6} (ethane), C{sub 4}H{sub 10} (butane), C{sub 6}H{sub 14} (hexane) C{sub 8}H{sub 18} (octane), C{sub 5}H{sub 5}N{sub 5} (adenine) and C{sub 5}H{sub 5}N{sub 5}O (guanine) have been introduced for incident electrons in the energy range 30 eV to 1 MeV. The range of electrons has been calculated within the continuous slowing down approximation (CSDA) using modified Rohrlich and Carlson formula of stopping power. Besides, we have calculated the mean penetration depths using a spherical geometric model developed by Bentabet (Vacuum 86:1855-1859, 35). The results have been compared with the other theoretical results, Monte Carlo code such as PENELOPE predictions and semi-empirical results. The calculated results of CSDA ranges for electrons in the energy range from 20 eV to 100 MeV are found to be in good agreement to within 10% with available date. (orig.)

  3. Microwave power coupling with electron cyclotron resonance ...

    Indian Academy of Sciences (India)

    600 W microwave power with an average electron density of ∼ 6 × 1011 cm. −3 ... the angular frequency of the cyclotron motion, e is the electron charge, m is the mass of .... is also suitable for ECR plasma-based applications like high-quality ...

  4. Microelectronics in power electronics and electrical drives

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    From October, 1214, 1982 at Darmstadt (FRG) a meeting took place on ''Microelectronics in power electronics and Electrical Drives''. This volume contains the papers of the 65 lectures, held at the symposium. For each of the 10 papers dealing with problems on electric-powered vehicles a separate subject analysis has been carried out.

  5. Stopping power of liquid water for carbon ions in the energy range between 1 MeV and 6 MeV

    International Nuclear Information System (INIS)

    Rahm, J M; Baek, W Y; Rabus, H; Hofsäss, H

    2014-01-01

    The stopping power of liquid water was measured for the first time for carbon ions in the energy range between 1 and 6 MeV using the inverted Doppler shift attenuation method. The feasibility study carried out within the scope of the present work shows that this method is well suited for the quantification of the controversial condensed phased effect in the stopping power for heavy ions in the intermediate energy range. The preliminary results of this work indicate that the stopping power of water for carbon ions with energies prevailing in the Bragg-peak region is significantly lower than that of water vapor. In view of the relatively high uncertainty of the present results, a new experiment with uncertainties less than the predicted difference between the stopping powers of both water phases is planned. (paper)

  6. Stopping power measurements with 17-GeV/c protons at the AGS or inclusive proton spectra from proton-nucleus interactions at 17 GeV/c

    International Nuclear Information System (INIS)

    Remsberg, L.P.; Barton, D.S.; Bunce, G.

    1984-01-01

    The problem of nuclear stopping power and its importance to the study of nucleus-nucleus collisions at very high energies was brought to general attention one year ago at Quark Matter 83 by Busza and Goldhaber. In this context, nuclear stopping power can be thought of as the rate of energy (or rapidity) loss of a proton traversing nuclear matter. It does not directly address the important question of energy deposition. Busza and Goldhaber showed that knowledge of nuclear stopping power is needed to estimate the minimum center-of-mass energy required in nucleus-nucleus collisions to ensure the production of very high temperatures at low baryon density. At cm energies of about 1 to 10 GeV/A, the stopping power is important in the estimation of the maximum baryon densities attainable in nucleus-nucleus collisions. The data presented are more relevant to this latter point

  7. Molecular dynamics simulations with electronic stopping can reproduce experimental sputtering yields of metals impacted by large cluster ions

    Science.gov (United States)

    Tian, Jiting; Zhou, Wei; Feng, Qijie; Zheng, Jian

    2018-03-01

    An unsolved problem in research of sputtering from metals induced by energetic large cluster ions is that molecular dynamics (MD) simulations often produce sputtering yields much higher than experimental results. Different from the previous simulations considering only elastic atomic interactions (nuclear stopping), here we incorporate inelastic electrons-atoms interactions (electronic stopping, ES) into MD simulations using a friction model. In this way we have simulated continuous 45° impacts of 10-20 keV C60 on a Ag(111) surface, and found that the calculated sputtering yields can be very close to the experimental results when the model parameter is appropriately assigned. Conversely, when we ignore the effect of ES, the yields are much higher, just like the previous studies. We further expand our research to the sputtering of Au induced by continuous keV C60 or Ar100 bombardments, and obtain quite similar results. Our study indicates that the gap between the experimental and the simulated sputtering yields is probably induced by the ignorance of ES in the simulations, and that a careful treatment of this issue is important for simulations of cluster-ion-induced sputtering, especially for those aiming to compare with experiments.

  8. Power Electronics Thermal Management R&D

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilbert; Bennion, Kevin

    2016-06-08

    This project will develop thermal management strategies to enable efficient and high-temperature wide-bandgap (WBG)-based power electronic systems (e.g., emerging inverter and DC-DC converter designs). The use of WBG-based devices in automotive power electronics will improve efficiency and increase driving range in electric-drive vehicles; however, the implementation of this technology is limited, in part, due to thermal issues. This project will develop system-level thermal models to determine the thermal limitations of current automotive power modules under elevated device temperature conditions. Additionally, novel cooling concepts and material selection will be evaluated to enable high-temperature silicon and WBG devices in power electronics components. WBG devices (silicon carbide [SiC], gallium nitride [GaN]) promise to increase efficiency, but will be driven as hard as possible. This creates challenges for thermal management and reliability.

  9. Power electronics and control for wind power systems

    DEFF Research Database (Denmark)

    Iov, Florin; Blaabjerg, Frede

    2009-01-01

    energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save...... the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging...

  10. Organic materials irradiated at very low temperature and at different stopping powers: examples of polyethylene and of cyclohexane molecules trapped in matrix

    International Nuclear Information System (INIS)

    Melot, M.

    2003-10-01

    This thesis concerns the formation mechanisms of defects created in organic materials during irradiation under vacuum, at very low temperature and at different electronic stopping powers. Analysis have been realised by infrared spectroscopy. The first part concerns polyethylene. Irradiating at 8 K allows to dissociate the direct irradiation effects (in cage reactions) and the radical recombination effects. According to the considered chemical groups, the radical mobility leads to very different changes for the formation radiochemical yields. The second part concerns the irradiation of cyclohexane molecules trapped in a solid argon matrix. We evaluate the contribution of intermolecular and intramolecular reactions. The intermolecular reactions have limited consequences when using low ionising radiations but are crucial for heavy ion irradiations. (author)

  11. The effect of an electronic "hard-stop" alert on HIV testing rates in the emergency department.

    Science.gov (United States)

    Schnall, Rebecca; Sperling, Jeremy D; Liu, Nan; Green, Robert A; Clark, Sunday; Vawdrey, David K

    2013-01-01

    Use of electronic alerts in clinical practice has had mixed effects on providers' prescribing practices. Little research has explored the use of electronic alerts for improving screening practices. New York City has one of the highest rates of HIV in the United States. Recent New York State legislation requires healthcare providers to offer an HIV test to patients aged 13-64 years during a clinical encounter. Adhering to this requirement is particularly challenging in emergency department (ED) settings, which are frequently overcrowded and under-resourced. The purpose of this study was to evaluate the effect of an electronic "hard-stop" alert on HIV testing rates in the ED. Approximately four months of data were reviewed before and after the implementation of the alert. We found that use of the electronic alert significantly increased documentation of offering an HIV test (O.R. = 267.27, p<0.001) and resulted in a significant increase in HIV testing. Findings from this study add to the current knowledge about the use of electronic alertsfor improving disease screening.

  12. Power electronic converters and systems frontiers and applications

    CERN Document Server

    Trzynadlowski, Andrzej M

    2016-01-01

    Power electronics is a branch of electrical engineering dealing with conversion and control of electric power using semiconductor power switches. This book provides an overview of modern power electronic converters and systems, and their applications.

  13. Generation of relativistic electron beam and its anomalous stopping in the fast ignition scheme

    International Nuclear Information System (INIS)

    Sengupta, S.; Sandhu, A.S.; Dharmadhikari, A.K.; Kumar, G.R.; Das, A.; Kaw, P.K.

    2005-01-01

    We present experimental/theoretical results concerning two main physics issues related to the fast ignition scheme viz. the nonlinear mechanism of conversion of incident laser energy into a relativistic electron beam at the critical layer and its subsequent transport through an overdense plasma. Theoretical/numerical modelling of the experimental data, firstly shows that the conversion of the laser energy into an inward propagating electron beam occurs through the nonlinear mechanism of wave breaking of plasma waves excited at the critical layer and, secondly the transport of the electron beam through the overdense plasma is influenced by electrostatically induced and/or turbulence induced anomalous resistivity. (author)

  14. Dirty tricks: how the nuclear lobby stopped the development of wave power in Britain

    International Nuclear Information System (INIS)

    Jeffery, J.

    1990-01-01

    It is claimed that by misrepresentation of the economic analysis of wave power generation of electricity the nuclear lobby in Britain has prevented development work to continue on wave power, in favour of nuclear power generation. The United Kingdom Department of Energy and the Central Electricity Generating Board, in favour of nuclear power, have not allowed the cost estimation of electricity from wave power generators, especially Salter's Ducks (a wave power generator generated by Professor Salter at Ednburgh University) to be known. Instead the cost (estimated at 4-12p/kWh) has been deliberately exaggerated. This has resulted in wind power becoming the favoured alternative renewable energy source of the future. (UK)

  15. Multidisciplinary Modelling Tools for Power Electronic Circuits

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad

    in reliability assessment of power modules, a three-dimensional lumped thermal network is proposed to be used for fast, accurate and detailed temperature estimation of power module in dynamic operation and different boundary conditions. Since an important issue in the reliability of power electronics...... environment to be used for optimization of cooling system layout with respect to thermal resistance and pressure drop reductions. Finally extraction of electrical parasitics in the multi-chip power modules will be investigated. As the switching frequency of power devices increases, the size of passive...... components are reduced considerably that leads to increase of power density and cost reduction. However, electrical parasitics become more challenging with increasing the switching frequency and paralleled chips in the integrated and denser packages. Therefore, electrical parasitic models are analyzed based...

  16. Power Electronics for Renewable Energy Systems

    DEFF Research Database (Denmark)

    Choi, U. M.; Lee, K. B.; Blaabjerg, Frede

    2012-01-01

    The use of renewable energy sources are increased because of the depletion of natural resources and the increasing pollution level from energy production. The wind energy and the solar energy are most widely used among the renewable energy sources. Power electronics is needed in almost all kinds...... of renewable energy system. It controls the renewable source and interfaces with the load effectively, which can be grid-connected or van work in stand-alone mode. In this presentation, overview of wind and photovoltaic energy systems are introduced. Next, the power electronic circuits behind the most common...

  17. Misconceptions impairing the validity of the stopping power tables in the SRIM library and suggestions for doing better in the future

    Science.gov (United States)

    Wittmaack, Klaus

    2016-08-01

    inconsistently from the predictions of Lindhard-Scharff (LS) theory; they also exhibit various forms of exotic velocity dependence. These deviations are primarily due to the fact that the range of validity of BB theory is artificially extended to velocities at which the 'effective-charge' concept is assumed to be applicable. Coupled Z1,2 scaling as in theories of LS or Firsov would be much more appropriate. Overall, the electronic stopping cross sections by SRIM are of unpredictable value and often strongly misleading below 1 MeV/u. (iv) Another consequence of the tight link to the Z1,2 dependence of BB theory is that only 2 × 92 master sets of electronic stopping cross sections were required to generate all conceivable 89 × 92 tables from Se,f-ratios for elemental targets (the tables for H, He and Li projectiles are derived separately). The information contained in the SRIM library at large thus exhibits a highly redundant character. (v) The nuclear stopping cross sections Sn mirror the predictions of the universal potential due by Ziegler, Biersack and Littmark, which differ from alternative suggestions typically by less than 15%. With this uncertainty, range distributions may be calculated with the TRIM program of SRIM, but only at energies where Sn dominates so that uncertainties in Se play a minor role. (vi) As a side aspect, an example is presented illustrating the efforts required to identify incorrect experimental data, notably when respected authors are accountable. (vii) Other approaches to establish stopping power tables are shown to be subject to the same problems as SRIM. It is recommended to add a warning to all theses tables, informing users at which energies the data are likely to lack reliability. (viii) The currently unacceptable quality of Se,f-data below 1 MeV/u could be improved significantly in the future if the user friendly TRIM(SRIM) code were modified to allow simulations with a free choice of nuclear and electronic stopping cross sections

  18. The 88-Inch Cyclotron: A One-Stop Facility for Electronics Radiation and Detector Testing

    Energy Technology Data Exchange (ETDEWEB)

    Kireeff Covo, M.; Albright, R. A.; Ninemire, B. F.; Johnson, M. B.; Hodgkinson, A.; Loew, T.; Benitez, J. Y.; Todd, D. S.; Xie, D. Z.; Perry, T.; Phair, L.; Bernsteiny, L. A.; Bevins, J.; Brown, J. A.; Goldblum, B. L.; Harasty, M.; Harrig, K. P.; Laplace, T. A.; Matthews, E. F.; Bushmaker, A.; Walker, D.; Oklejas, V.; Hopkins, A. R.; Bleuel, D. L.; Chen, J.; Cronin, S. B.

    2017-10-01

    In outer space down to the altitudes routinely flown by larger aircrafts, radiation can pose serious issues for microelectronics circuits. The 88-Inch Cyclotron at Lawrence Berkeley National Laboratory is a sector-focused cyclotron and home of the Berkeley Accelerator Space Effects Facility, where the effects of energetic particles on sensitive microelectronics are studied with the goal of designing electronic systems for the space community. This paper describes the flexibility of the facility and its capabilities for testing the bombardment of electronics by heavy ions, light ions, and neutrons. Experimental capabilities for the generation of neutron beams from deuteron breakups and radiation testing of carbon nanotube field effect transistor will be discussed.

  19. Stopping power measurements for 4-5MeV/nucleon 16O, 40Ar, 63Cu and 84Kr in C, Al, Ni, Ag and Au

    International Nuclear Information System (INIS)

    Bimbot, R.; Della Negra, S.; Gardes, D.; Gauvin, H.; Fleury, A.; Hubert, F.

    1977-01-01

    The stopping powers for (4 and 5 MeV/nucleon) 16 O, 40 Ar, 63 Cu and 84 Kr have been measured in C, Al, Ni, Ag and Au media. The experimental technique consists in measuring accurately the energy of protons elastically scattered at zero degree by the incident and degraded beams. The experimental results have been compared with stopping powers calculated in different ways. Discrepancies as large as 30% have been observed for the heaviest ions in light media (C, Al), the experimental values being higher than the calculated ones. Moreover, this comparison indicates that, from these calculations, no agreement can be obtained in the whole range of incident ions and stopping media. On the contrary, a quantitative agreement was obtained by a new calculation mode which takes into account the variation of the moving ion effective charge with the atomic number of the stopping medium

  20. Evaluation of possible means to stop production of nuclear power in northwest Russia

    International Nuclear Information System (INIS)

    Skaugen, Aud K.

    2007-08-01

    This note illuminates the status and some elements in the Russian efforts on use of nuclear power, with special emphasis on northwest Russia. In addition the report describes an evaluation of the possibilities of Norwegian influence on the nuclear power in northwest Russia and Kola Peninsula

  1. Protection device for use in stopping a turbine generator in nuclear power plant

    International Nuclear Information System (INIS)

    Nagahama, Mizuo.

    1974-01-01

    Object: To supply to as great an extent as possible the residual output of a nuclear reactor to a turbine after the reactor is shutdown and to prevent overpower and motoring of a turbine by connecting a power direction relay to a secondary circuit of a current transformer and an instrumentation transformer at the high voltage side of a main transformer of a transmission bus line. Structure: When the output power of a generator after shuttingdown a nuclear reactor decreases below the sum of the mechanical losses of the turbine and the generator and the power for the house-auxiliaries connected to a fixed bus line, the direction of the current is reversed and the power is supplied from the transmission bus line through a circuit breaker for the generator and a main transformer onto the house-side, whereby a time limit relay of the power direction relay is actuated to disconnect the generator and the turbine. (Kamimura, M.)

  2. Advanced Power Electronics and Smart Inverters | Grid Modernization | NREL

    Science.gov (United States)

    Advanced Power Electronics and Smart Inverters Advanced Power Electronics and Smart Inverters , into the electric distribution system requires advanced power electronics, or smart inverters, that . Contact Sudipta Chakraborty Power Electronics Team Lead sudipta.chakraborty@nrel.gov | 303-384-7093

  3. Power Electronics and Electric Machines | Transportation Research | NREL

    Science.gov (United States)

    Power Electronics and Electric Machines NREL's power electronics and electric machines research helping boost the performance of power electronics components and systems, while driving down size, weight technical barriers to EDV commercialization. EDVs rely heavily on power electronics to distribute the proper

  4. DC power supplies power management and surge protection for power electronic systems

    CERN Document Server

    Kularatna, Nihal

    2011-01-01

    Modern electronic systems, particularly portable consumer electronic systems and processor based systems, are power hungry, compact, and feature packed. This book presents the most essential summaries of the theory behind DC-DC converter topologies of both linear and switching types. The text discusses power supply characteristics and design specifications based on new developments in power management techniques and modern semiconductors entering into the portable electronics market. The author also addresses off-the-line power supplies, digital control of power supply, power supply protection

  5. Partial and total electronic stopping cross sections of atoms and solids for protons

    International Nuclear Information System (INIS)

    Kaneko, Toshiaki.

    1990-12-01

    Based on a wave packet theory (Phys. Rev. A40, 2188(1989); Phys. Stat. Sol. (B)156,49(1989)), partial and total electronic cross sections of target elements in atomic and solid phases with atomic number Z ranging from 2 (He) to 92 (U) are tabulated shell by shell for protons with velocity v from 0.2V 0 to 2OV 0 (V 0 =2.18 x 10 8 cm/s). (author)

  6. Stopping power accuracy and achievable spatial resolution of helium ion imaging using a prototype particle CT detector system

    Directory of Open Access Journals (Sweden)

    Volz Lennart

    2017-09-01

    Full Text Available A precise relative stopping power map of the patient is crucial for accurate particle therapy. Charged particle imaging determines the stopping power either tomographically – particle computed tomography (pCT – or by combining prior knowledge from particle radiography (pRad and x-ray CT. Generally, multiple Coulomb scattering limits the spatial resolution. Compared to protons, heavier particles scatter less due to their lower charge/mass ratio. A theoretical framework to predict the most likely trajectory of particles in matter was developed for light ions up to carbon and was found to be the most accurate for helium comparing for fixed initial velocity. To further investigate the potential of helium in particle imaging, helium computed tomography (HeCT and radiography (HeRad were studied at the Heidel-berg Ion-Beam Therapy Centre (HIT using a prototype pCT detector system registering individual particles, originally developed by the U.S. pCT collaboration. Several phantoms were investigated: modules of the Catphan QA phantom for analysis of spatial resolution and achievable stopping power accuracy, a paediatric head phantom (CIRS and a custom-made phantom comprised of animal meat enclosed in a 2 % agarose mixture representing human tissue. The pCT images were reconstructed applying the CARP iterative reconstruction algorithm. The MTF10% was investigated using a sharp edge gradient technique. HeRad provides a spatial resolution above that of protons (MTF1010%=6.07 lp/cm for HeRad versus MTF10%=3.35 lp/cm for proton radiography. For HeCT, the spatial resolution was limited by the number of projections acquired (90 projections for a full scan. The RSP accuracy for all inserts of the Catphan CTP404 module was found to be 2.5% or better and is subject to further optimisation. In conclusion, helium imaging appears to offer higher spatial resolution compared to proton imaging. In future studies, the advantage of helium imaging compared to other

  7. UWB Filtering Power Divider with Two Narrow Notch-bands and Wide Stop-band

    Science.gov (United States)

    Wei, Feng; Wang, Xin-Yi; Zou, Xin Tong; Shi, Xiao Wei

    2017-12-01

    A compact filtering ultra-wideband (UWB) microstrip power divider (PD) with two sharply rejected notch-bands and wide stopband is analyzed and designed in this paper. The proposed UWB PD is based on a conventional Wilkinson power divider, while two stub loaded resonators (SLRs) are coupled into two symmetrical output ports to achieve a bandpass filtering response. The simplified composite right/left-handed (SCRLH) resonators are employed to generate the dual notched bands. Defected ground structure (DGS) is introduced to improve the passband performance. Good insertion/return losses, isolation and notch-band rejection are achieved as demonstrated in both simulation and experiment.

  8. Applying power electronics to residential HVAC

    International Nuclear Information System (INIS)

    Sulfstede, L.

    1991-01-01

    This paper outlines several of the market and application issues bearing on the economics residential variable speed air conditioners and heat pumps. Technical details of capacity modulized systems have been avoided, along with design issues and tradeoffs involving power semiconductors, motor torque and speed control strategies- and silicon integration for these applications. The intention is to provoke new creative technical solutions but perhaps more importantly, to involve new marketing strategies that will develop the mature potential of air conditioning products containing power electronics to enable them to generate the tough HVAC market, competing successfully against conventional systems

  9. Inertial-confinement-fusion applications of ion-stopping theory

    International Nuclear Information System (INIS)

    More, R.M.; Lee, Y.T.; Bailey, D.S.

    1982-01-01

    Methods were developed to calculate: (1) the stopping power of a hot plasma target, (2) the charge-state of a fast ion projectile, and (3) the final disposition of the deposited energy. The first issue refers to the stopping power for protons. The proton stopping power is altered in high-density or high-temperature targets, especially at velocities below the stopping peak. The second issue concerns the application of a proton stopping curve to the arbitrary projectile. The third topic is more specialized to inertial fusion and concerns the partition of deposited energy between ion (nuclear motion) degrees of freedom and those corresponding to bound and free electrons. The question here is whether a thermal equilibrium plasma is produced

  10. Measurement of neutrino electron scattering and inverse beta-decay of carbon using neutrinos from stopped muon decay

    International Nuclear Information System (INIS)

    Krakauer, D.A.

    1992-04-01

    Electron-neutrino electron elastic scattering and two-body electron- neutrino carbon scattering reactions were observed using a 15 ton fine-grained detector and neutrinos from μ + decay at rest. The data was obtained during an exposure to neutrinos produced in LAMPF proton beam-stop. Based on identification of 262±46 ν e e - events the total cross-section for ν e e - → ν e e - was measured to be σ(ν e E - ) = (3.09±0.54(stat)±0.39(syst)) x 10 -43 cm 2 . The interference between the weak charged and neutral currents was measured for the first time. The interference was found to be destructive, with a magnitude 0.97±0.22 times the value predicted by the WSG theory. The total cross-section was also used to measure sin 2 θ W = 0.24±0.06(stat)±0.04(syst). The data restricts the maximum allowed value of the neutrino magnetic moment to be less than 1.3 x 10 -9 Bohr magnetrons for ν e and 8.8 x 10 -10 for ν mu . In a separate analysis, 182±22 12 C(ν e ,e - ) 12 N(gs) events with subsequent 12 N(β + ) 12 C were observed, corresponding to a total cross-section, σ(ν e 12 C → e - 12 N(gs)) = (1.03 ± 0.12(stat) ± 0.10(sys)) x10 -41 cm 2 . This was the first observation of ν e -induced transitions between specific nuclear states. The results is good agreement with theoretical predictions

  11. Advanced Power Electronics and Electric Motors Annual Report -- 2013

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bennion, K. [National Renewable Energy Lab. (NREL), Golden, CO (United States); DeVoto, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Moreno, G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Rugh, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Waye, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-01-01

    This report describes the research into advanced liquid cooling, integrated power module cooling, high temperature air cooled power electronics, two-phase cooling for power electronics, and electric motor thermal management by NREL's Power Electronics group in FY13.

  12. Nuclear power and the electronics revolution

    International Nuclear Information System (INIS)

    Konstantinov, L.; Joosten, J.; Neboyan, V.

    1985-01-01

    This article mentions a number of innovations and electronic tools, which are influencing nuclear plant operations. Examples are: The incorporation of digital computer devices in safety systems; The application of noise analysis techniques to serveillance systems of nuclear power plants; The use of nuclear power plant training simulators; The attention period to the man-machine interface; The developments in the field of robot uses and remote systems in nuclear power plants. A recommendation is made to all countries to make the best use of the IAEA policy to promote international cooperation and exchange of experience in this field. Reference is made to the international conference on ''Man-Machine Interface in the Nuclear Industry; Control and Instrumentation, Robot Uses and Artificial Intelligence'' that IAEA is planning to hold in 1987

  13. Power Electronic Packaging Design, Assembly Process, Reliability and Modeling

    CERN Document Server

    Liu, Yong

    2012-01-01

    Power Electronic Packaging presents an in-depth overview of power electronic packaging design, assembly,reliability and modeling. Since there is a drastic difference between IC fabrication and power electronic packaging, the book systematically introduces typical power electronic packaging design, assembly, reliability and failure analysis and material selection so readers can clearly understand each task's unique characteristics. Power electronic packaging is one of the fastest growing segments in the power electronic industry, due to the rapid growth of power integrated circuit (IC) fabrication, especially for applications like portable, consumer, home, computing and automotive electronics. This book also covers how advances in both semiconductor content and power advanced package design have helped cause advances in power device capability in recent years. The author extrapolates the most recent trends in the book's areas of focus to highlight where further improvement in materials and techniques can d...

  14. Accurate stopping power determination of 15N ions for hydrogen depth profiling by a combination of ion beams and synchrotron radiation

    Science.gov (United States)

    Zier, M.; Reinholz, U.; Riesemeier, H.; Radtke, M.; Munnik, F.

    2012-02-01

    Hydrogen analysis is of particular importance in thin film technology and it is often necessary to obtain a depth profile. The method with the best depth resolution is NRA using the 6385 keV resonance of the 1H( 15N,αγ) 12C nuclear reaction. The correct quantification of the depth and concentration scales in the measured hydrogen profiles relies on accurate stopping power values. We present a method to deduce these values from a combination of two techniques: NRA and X-ray reflectometry (XRR). This method is applied to the determination of the stopping power of ˜6.4 MeV 15N ions in H-containing amorphous Si-layers (a-Si:H). Density-independent stopping powers at different H concentrations are determined by combining the results from NRA and XRR with an overall uncertainty of 3.3%, showing good agreement with SRIM values. This work shows exemplary the methodology for future evaluation of stopping powers for quality assurance in NRA.

  15. Interaction of protons with the C{sub 60} molecule: calculation of deposited energies and electronic stopping cross sections (v{sub {<=}}5 au)

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P. [Laboratoire CAR, IRSAMC, UMR 5589 CNRS, Universite Paul Sabatier, Toulouse (France)]. E-mail: pmc@irsamc.ups-tlse.fr; Bordenave-Montesquieu, D.; Rentenier, A.; Bordenave-Montesquieu, A. [Laboratoire CAR, IRSAMC, UMR 5589 CNRS, Universite Paul Sabatier, Toulouse (France)

    2001-09-28

    The energy deposited by a proton in a C{sub 60} molecule is calculated over a broad collision velocity range from 0.1 to 5 au, using the free-electron gas model of Lindhard and Winther (1964 Mat. Fys. Medd. K Dan. Vidensk. Selsk. 34) and the C{sub 60} electron density distribution calculated by Puska and Nieminen. The energy lost by the proton is maximum near 1.8 au collision velocity in contrast with the saturation found in the low-velocity regime, in the 0.25-0.5 au velocity range, by Kunert and Schmidt. From the impact parameter dependence we deduce the distributions of deposited energies, the averaged energy losses and the C{sub 60} electronic stopping cross sections. It is found that the C{sub 60} molecule behaves as a carbon foil giving very similar absolute stopping cross sections per atom. (author). Letter-to-the-editor.

  16. Wide Bandgap Semiconductor Opportunities in Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Marlino, Laura D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Kristina O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2018-01-01

    The report objective is to explore the Wide Bandgap (WBG) Power Electronics (PE) market, applications, and potential energy savings in order to identify key areas where further resources and investments of the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE EERE) would have the most impact on U.S. competiveness. After considering the current market, several potential near-term application areas were identified as having significant market and energy savings potential with respect to clean energy applications: (1) data centers (uninterruptible power supplies and server power supplies); (2) renewable energy generation (photovoltaic-solar and wind); (3) motor drives (industrial, commercial and residential); (4) rail traction; and, (5) hybrid and electric vehicles (traction and charging). After the initial explorative analyses, it became clear that, SiC, not GaN, would be the principal WBG power device material for the chosen markets in the near future. Therefore, while GaN is discussed when appropriate, this report focuses on SiC devices, other WBG applications (e.g., solid-state transformers, combined heat and power, medical, and wireless power), the GaN market, and GaN specific applications (e.g., LiDAR, 5G) will be explored at a later date. In addition to the market, supply and value chain analyses addressed in Section 1 of this report, a SWOT (Strength, Weakness, Opportunity, Threat) analysis and potential energy savings analysis was conducted for each application area to identify the major potential WBG application area(s) with a U.S. competitiveness opportunity in the future.

  17. Mono and sequential ion irradiation induced damage formation and damage recovery in oxide glasses: Stopping power dependence of the mechanical properties

    International Nuclear Information System (INIS)

    Mir, A.H.; Monnet, I.; Toulemonde, M.; Bouffard, S.; Jegou, C.; Peuget, S.

    2016-01-01

    Simple and complex borosilicate glasses were irradiated with single and double ion beams of light and heavy ions over a broad fluence and stopping power range. As a result of the heavy ion irradiation (U, Kr, Au), the hardness was observed to diminish and saturate after a decrease by 35 ± 1%. Unlike slow and swift heavy ion irradiation, irradiation with light ions (He,O) induced a saturation hardness decrease of 18 ± 1% only. During double ion beam irradiation; where glasses were first irradiated with a heavy ion (gold) and then by a light ion (helium), the light ion irradiation induced partial damage recovery. As a consequence of the recovery effect, the hardness of the pre-irradiated glasses increased by 10–15% depending on the chemical composition. These results highlight that the nuclear energy loss and high electronic energy loss (≥4 keV/nm) result in significant and similar modifications whereas light ions with low electronic energy loss (≤1 keV/nm) result in only mild damage formation in virgin glasses and recovery in highly pre-damaged glasses. These results are important to understand the damage formation and recovery in actinide bearing minerals and in glasses subjected to self-irradiation by alpha decays. - Highlights: • Behavior of glasses strongly depends on the electronic energy loss (Se) of the ions. • High Se (≥4 keV/nm) induces large changes in comparison to lower Se values. • Apart from mild damage formation, low Se causes recovery of pre-existing damage. • Alpha induced partial recovery of the damage would occur in nuclear waste glasses.

  18. Power electronics basics operating principles, design, formulas, and applications

    CERN Document Server

    Rozanov, Yuriy; Chaplygin, Evgeny; Voronin, Pavel

    2015-01-01

    Power Electronics Basics: Operating Principles, Design, Formulas, and Applications provides fundamental knowledge for the analysis and design of modern power electronic devices. This concise and user-friendly resource:Explains the basic concepts and most important terms of power electronicsDescribes the power assemblies, control, and passive components of semiconductor power switchesCovers the control of power electronic devices, from mathematical modeling to the analysis of the electrical processesAddresses pulse-width modulation, power quality control, and multilevel, modular, and multicell

  19. Power Electronics and Thermal Management | Transportation Research | NREL

    Science.gov (United States)

    Power Electronics and Thermal Management Power Electronics and Thermal Management This is the March Gearhart's testimony. Optical Thermal Characterization Enables High-Performance Electronics Applications New vehicle electronics systems are being developed at a rapid pace, and NREL is examining strategies to

  20. Piezoelectric energy harvesting for powering low power electronics

    Energy Technology Data Exchange (ETDEWEB)

    Leinonen, M.; Palosaari, J.; Hannu, J.; Juuti, J.; Jantunen, H. (Univ. of Oulu, Dept. of Electrical and Information Engineering (Finland)). email: jajuu@ee.oulu.fi

    2009-07-01

    Although wireless data transmission techniques are commonly used in electronic devices, they still suffer from wires for the power supply or from batteries which require charging, replacement and other maintenance. The vision for the portable electronics and industrial measurement systems of the future is that they are intelligent and independent on their energy supply. The major obstacle in this path is the energy source which enables all other functions and 'smartness' of the systems as the computing power is also restricted by the available energy. The development of long-life energy harvesters would reduce the need for batteries and wires thus enabling cost-effective and environment friendlier solutions for various applications such as autonomous wireless sensor networks, powering of portable electronics and other maintenance-free systems. One of the most promising techniques is mechanical energy harvesting e.g. by piezoelectric components where deformations produced by different means is directly converted to electrical charge via direct piezoelectric effect. Subsequently the electrical energy can be regulated or stored for further use. The total mechanical energy in vibration of machines can be very large and usually only a fraction of it can be transformed to electrical energy. Recently, piezoelectric vibration based energy harvesters have been developed widely for different energy consumption and application areas. As an example for low energy device an piezoelectric energy harvester based on impulse type excitations has been developed for active RFID identification. Moreover, piezoharvester with externally leveraged mechanism for force amplification was reported to be able to generate mean power of 0.4 mW from backpack movement. Significantly higher power levels are expected from larger scale testing in Israel, where piezoelectric material is embedded under active walking street, road, airport or railroad. The energy is harvested from human or

  1. Experimental verification of stopping-power prediction from single- and dual-energy computed tomography in biological tissues

    Science.gov (United States)

    Möhler, Christian; Russ, Tom; Wohlfahrt, Patrick; Elter, Alina; Runz, Armin; Richter, Christian; Greilich, Steffen

    2018-01-01

    An experimental setup for consecutive measurement of ion and x-ray absorption in tissue or other materials is introduced. With this setup using a 3D-printed sample container, the reference stopping-power ratio (SPR) of materials can be measured with an uncertainty of below 0.1%. A total of 65 porcine and bovine tissue samples were prepared for measurement, comprising five samples each of 13 tissue types representing about 80% of the total body mass (three different muscle and fatty tissues, liver, kidney, brain, heart, blood, lung and bone). Using a standard stoichiometric calibration for single-energy CT (SECT) as well as a state-of-the-art dual-energy CT (DECT) approach, SPR was predicted for all tissues and then compared to the measured reference. With the SECT approach, the SPRs of all tissues were predicted with a mean error of (-0.84  ±  0.12)% and a mean absolute error of (1.27  ±  0.12)%. In contrast, the DECT-based SPR predictions were overall consistent with the measured reference with a mean error of (-0.02  ±  0.15)% and a mean absolute error of (0.10  ±  0.15)%. Thus, in this study, the potential of DECT to decrease range uncertainty could be confirmed in biological tissue.

  2. Experimental study on the influence of charge exchange on the stopping power in the interaction of chlorine with a gas and a deuterium plasma

    International Nuclear Information System (INIS)

    Nectoux, Marie

    1998-01-01

    This thesis is placed in the context of the physics of energy deposition of a multicharged heavy ion beam in matter at intermediate energies. The experiment gave measurements of energy loss as a function of final charge state for chlorine ions at 1.7 MeV/u in deuterium gas or plasma. In this way, we explore the influence of charge state evolution, depending on experimentally measured capture and ionization cross sections and the electron density of the target, on energy loss. The target is cylindrical and enclosed by two fast valves. The plasma is created in the gas by a discharge, which induces a magnetic perturbation of the beam (lens effect). This effect induces a divergent and misaligned outgoing beam. A simulation including charge state and velocity evolution of the projectile in flight in the magnetic field has been made in order to optimize beam analysis, to reach a precision better than 10 -3 in energy measurement. This study led to removal of the target to the 'Split Pole', a refocusing magnetic spectrometer. The first results obtained clearly show the dependence of energy loss on exit charge and especially on its evolution in the target. This is explained in terms of the lengths covered by the projectile in its successive charge states in the target, which depends on target electron density and the medium considered. In plasma, we observed an energy distribution with exit charge twice that observed in gas, because of a strong decrease of charge exchange. A comparison of data obtained in gas with stopping power calculated from Bethe-Bloch-Barkas theory leads to the necessity of including spatial extension of the projectile charge in the theory. (author)

  3. Power Electronics and Controls for Wind Turbine Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Iov, Florin; Chen, Zhe

    2010-01-01

    term) based energy sources to renewable energy sources. Another is to use power electronics to achieve high efficiency in power generation, transmission/distribution and utilization. This paper discuss trends of the most promising renewable energy sources, wind energy, which ,integrated with power...... electronics, is changing the future electrical infrastructure and also contributes steadily to non-carbon based electricity production. The paper’s focus is on the power electronics technologies used in wind turbine systems....

  4. Application of high power microwave vacuum electron devices

    International Nuclear Information System (INIS)

    Ding Yaogen; Liu Pukun; Zhang Zhaochuan; Wang Yong; Shen Bin

    2011-01-01

    High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

  5. Smart training environment for power electronics

    Science.gov (United States)

    Hinov, Nikolay; Hranov, Tsveti

    2017-12-01

    The idea of the paper is to present a successful symbiosis of the products of the leading firms in the electronics - National Instruments and Texas Instruments. The developed test bench is composed of hardware for data acquisition and control (sbRIO), working with the LabVIEW environment and the novel Power Management Lab Kit (PMLK) educational boards. The manipulation of these hi-tech boards becomes more accessible for a broader range of students, including undergraduates in schools, with the use of LabVIEW virtual instruments (VI), which assist the trainees in the manipulation of the kits - for example if a incompatible working configuration is set, the VI will pop up a message describing the result if its execution. Moreover it will provide guidance for choosing the right setup along the active decisions from the student and also with the VI can be taken measurements, without the need of external hardware.

  6. Comprehensive analysis of proton range uncertainties related to patient stopping-power-ratio estimation using the stoichiometric calibration

    Science.gov (United States)

    Yang, Ming; Zhu, X. Ronald; Park, Peter C.; Titt, Uwe; Mohan, Radhe; Virshup, Gary; Clayton, James E.; Dong, Lei

    2012-07-01

    The purpose of this study was to analyze factors affecting proton stopping-power-ratio (SPR) estimations and range uncertainties in proton therapy planning using the standard stoichiometric calibration. The SPR uncertainties were grouped into five categories according to their origins and then estimated based on previously published reports or measurements. For the first time, the impact of tissue composition variations on SPR estimation was assessed and the uncertainty estimates of each category were determined for low-density (lung), soft, and high-density (bone) tissues. A composite, 95th percentile water-equivalent-thickness uncertainty was calculated from multiple beam directions in 15 patients with various types of cancer undergoing proton therapy. The SPR uncertainties (1σ) were quite different (ranging from 1.6% to 5.0%) in different tissue groups, although the final combined uncertainty (95th percentile) for different treatment sites was fairly consistent at 3.0-3.4%, primarily because soft tissue is the dominant tissue type in the human body. The dominant contributing factor for uncertainties in soft tissues was the degeneracy of Hounsfield numbers in the presence of tissue composition variations. To reduce the overall uncertainties in SPR estimation, the use of dual-energy computed tomography is suggested. The values recommended in this study based on typical treatment sites and a small group of patients roughly agree with the commonly referenced value (3.5%) used for margin design. By using tissue-specific range uncertainties, one could estimate the beam-specific range margin by accounting for different types and amounts of tissues along a beam, which may allow for customization of range uncertainty for each beam direction.

  7. Range-energy relations and stopping power of water, water vapour and tissue equivalent liquid for α particles over the energy range 0.5 to 8 MeV

    International Nuclear Information System (INIS)

    Palmer, R.B.J.; Akhavan-Rezayat, Ahmad

    1978-01-01

    Experimental range-energy relations are presented for alpha particles in water, water vapour and tissue equivalent liquid at energies up to 8 MeV. From these relations differential stopping powers are derived at 0.25 MeV energy intervals. Consideration is given to sources of error in the range-energy measurements and to the uncertainties that these will introduce into the stopping power values. The ratio of the differential stopping power of muscle equivalent liquid to that of water over the energy range 0.5 to 7.5 MeV is discussed in relation to the specific gravity and chemical composition of the muscle equivalent liquid. Theoretical molecular stopping power calculations based upon the Bethe formula are also presented for water. The effect of phase upon the stopping power of water is discussed. The molecular stopping power of water vapour is shown to be significantly higher than that of water for energies below 1.25 MeV and above 2.5 MeV, the ratio of the two stopping powers rising to 1.39 at 0.5 MeV and to 1.13 at 7.0 MeV. Stopping power measurements for other liquids and vapours are compared with the results for water and water vapour and some are observed to have stopping power ratios in the vapour and liquid phases which vary with energy in a similar way to water. It is suggested that there may be several factors contributing to the increased stopping power of liquids. The need for further experimental results on a wider range of liquids is stressed

  8. Design for Reliability of Power Electronics in Renewable Energy Systems

    DEFF Research Database (Denmark)

    Ma, Ke; Yang, Yongheng; Wang, Huai

    2014-01-01

    Power electronics is the enabling technology for maximizing the power captured from renewable electrical generation, e.g., the wind and solar technology, and also for an efficient integration into the grid. Therefore, it is important that the power electronics are reliable and do not have too many...... failures during operation which otherwise will increase cost for operation, maintenance and reputation. Typically, power electronics in renewable electrical generation has to be designed for 20–30 years of operation, and in order to do that, it is crucial to know about the mission profile of the power...... electronics technology as well as to know how the power electronics technology is loaded in terms of temperature and other stressors relevant, to reliability. Hence, this chapter will show the basics of power electronics technology for renewable energy systems, describe the mission profile of the technology...

  9. Single-stage unity power factor based electronic ballast

    Indian Academy of Sciences (India)

    This paper deals with the design, modeling, analysis and implementation of unity power factor (UPF) based electronic ballast for a fluorescent lamp (FL). The proposed electronic ballast uses a boost AC–DC converter as a power factor corrector (PFC) to improve the power quality at the input ac mains. In this singlestage ...

  10. High Power Electronics - Key Technology for Wind Turbines

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke

    2014-01-01

    reliability challenges for the future wind turbines are explained. It is concluded that the wind turbine behavior/performance can be significantly improved by introducing power electronics, and there will be higher requirements for the power electronics performances in wind power application....

  11. Stopping powers of havar and effective charge for 1.4-3.2 MeV/u {sup 127}I-ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Raeisaenen, J.; Virtanen, A

    2000-06-01

    Stopping powers of havar for 1.4-3.2 MeV/u {sup 127}I-ions have been determined by the transmission technique using two geometrical arrangements. No previous data have been published for havar with this ion. The experimental data are compared with predictions obtained by using Bragg's additivity rule with various parametrizations of the stopping power found in the literature. The values obtained by the parametrizations underestimate the experimental data by 5-11%. The empirical correction scheme of Thwaites yields values in rather good agreement with the present results, especially at energies above 1.9 MeV/u. The effective charges of the {sup 127}I ions were also deduced from the experimental data.

  12. Power Electronics Converters for Wind Turbine Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Liserre, Marco; Ma, Ke

    2012-01-01

    The steady growth of installed wind power together with the upscaling of the single wind turbine power capability has pushed the research and development of power converters toward full-scale power conversion, lowered cost pr kW, increased power density, and also the need for higher reliability. ...

  13. The precision of proton range calculations in proton radiotherapy treatment planning: experimental verification of the relation between CT-HU and proton stopping power

    International Nuclear Information System (INIS)

    Schaffner, B.; Pedroni, E.

    1998-01-01

    The precision in proton radiotherapy treatment planning depends on the accuracy of the information used to calculate the stopping power properties of the tissues in the patient's body. This information is obtained from computed tomography (CT) images using a calibration curve to convert CT Hounsfield units into relative proton stopping power values. The validity of a stoichiometric method to create the calibration curve has been verified by measuring pairs of Hounsfield units and stopping power values for animal tissue samples. It was found that the agreement between measurement and calibration curve is better than 1% if beam hardening effects in the acquisition of the CT images can be neglected. The influence of beam hardening effects on the quantitative reading of the CT measurements is discussed and an estimation for the overall range precision of proton beams is given. It is expected that the range of protons in the human body can be controlled to better than ±1.1% of the water equivalent range in soft tissue and ±1.8% in bone, which translates into a range precision of about 1-3 mm in typical treatment situations. (author)

  14. Experimental study of ion stopping power in warm dense matter: charge-state distribution measurements of ions leaving warm dense matter

    International Nuclear Information System (INIS)

    Gauthier, Maxence

    2013-01-01

    The determination if the ion slowing down process (or stopping power) in warm dense matter is essential especially in the frame of inertial confinement fusion. During my thesis, our interest was driven by the modification of the charge state of ion beam emerging from warm dense matter, this quantity playing a major role in ion stopping power calculation. We took advantage of the properties exhibited by ion beams produced by high intensity short pulse lasers to study during two experiments performed at ELFIE and TITAN facilities, the charge state modification of a carbon and helium ion beams emerging from an aluminum foil isochorically heated by an energetic proton beam. In the first two chapters are presented the major challenges regarding the subject from both a theoretical and experimental point of view. Here are exposed the different simulation tools used during the thesis. The third chapter is devoted to the study of the property of laser-produced ion beams in the scope of our experiments aiming at studying the stopping power. We have studied in particular ion beams generated using lower-than-solid density targets during two experiments: helium gas jet and laser-exploded target. In the last chapter are presented the set-ups and results of the two experiments on the charge state of ion beam emerging from warm dense matter. The data we measured in solid-density cold aluminum are successfully compared with the results already obtained in conventional accelerators. (author) [fr

  15. Stopping powers of havar for 1.6, 2.3 and 3.2 MeV/u heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Raeisaenen, J.; Virtanen, A

    2000-03-01

    Stopping powers of havar for {sup 28,30}Si-, {sup 36}Ar-, {sup 54,56}Fe- and {sup 80,84}Kr-ions with energies of 1.6, 2.3 and 3.2 MeV/u have been determined by a transmission technique. Sample foils are exposed to the direct beams. No previous data for havar with these ions have been published. The obtained results are brought together with literature havar data for {sup 1}H-, {sup 4}He-, {sup 7}Li-, {sup 11}B-, {sup 12}C-, {sup 14}N-, {sup 16}O- and {sup 127}I-ions at the same ion velocity. The experimental data are compared with the values predicted by the SRIM-2000 parametrization using Bragg's rule. A systematic underestimation, by 6-23%, of the experimental stopping powers was observed. The empirical correction scheme of Thwaites has been applied to the stopping power values obtained by the parametrization. The corrected values agree well with the present results. Also, the effective charge values of the various ions were deduced from the experimental set of data.

  16. Polycarbonate, Mylar and Havar stopping powers for 1.0-3.25 MeV/nucleon {sup 40}Ar-ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae (Finland)]. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Laitinen, P.; Matilainen, A.; Raeisaenen, J.; Virtanen, A. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae (Finland)

    2001-12-03

    Stopping powers of polycarbonate, Mylar and Havar for 1.0-3.25 MeV/nucleon {sup 40}Ar-ions have been determined by the transmission method in two geometries. The stopping power values were obtained within uncertainty of 2.1-4.5% for the various materials. The present results are compared with the predictions obtained by the most commonly used procedures employed in obtaining stopping powers. These include the Northcliffe and Schilling model, semi-empirical parametrization of Ziegler et al (SRIM2000) with and without the cores and bonds model and the Hubert et al formulation. SRIM2000 values were in good agreement in case of Mylar and Havar, on average within 3% of present results. For polycarbonate the differences were less than 6% on average. The cores and bonds (CAB) model improved the parametrization values slightly. The Northcliffe and Schilling model and the Hubert et al formulation both yielded values within 5% or less for Mylar and polycarbonate. For the Havar the Hubert et al formulation and the present results disagreed by 10% on average. (author)

  17. Power Electronics, Energy Harvesting and Renewable Energies Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The research in the Power Electronics, Energy Harvesting and Renewable Energies Laboratory (PEHREL) is mainly focused on investigation, modeling, simulation, design,...

  18. SU-F-J-195: On the Performance of Four Dual Energy CT Formalisms for Extracting Proton Stopping Powers

    Energy Technology Data Exchange (ETDEWEB)

    Baer, E; Royle, G [University College London, London (United Kingdom); Lalonde, A; Bouchard, H [University of Montreal, Montreal, QC (Canada)

    2016-06-15

    Purpose: Dual energy CT can predict stopping power ratios (SPR) for ion therapy treatment planning. Several approaches have been proposed recently, however accuracy and practicability in a clinical workflow are unaddressed. The aim of this work is to provide a fair comparison of available approaches in a human-like phantom to find the optimal method for tissue characterization in a clinical situation. Methods: The SPR determination accuracy is investigated using simulated DECT images. A virtual human-like phantom is created containing 14 different standard human tissues. SECT (120 kV) and DECT images (100 kV and 140 kV Sn) are simulated using the software ImaSim. The single energy CT (SECT) stoichiometric calibration method and four recently published calibration-based DECT methods are implemented and used to predict the SPRs from simulated images. The difference between SPR predictions and theoretical SPR are compared pixelwize. Mean, standard deviation and skewness of the SPR difference distributions are used as measures for bias, dispersion and symmetry. Results: The average SPR differences and standard deviations are (0.22 ± 1.27)% for SECT, and A) (−0.26 ± 1.30)%, B) (0.08 ± 1.12)%, C) (0.06 ± 1.15)% and D) (−0.05 ± 1.05)% for the four DECT methods. While SPR prediction using SECT is showing a systematic error on SPR, the DECT methods B, C and D are unbiased. The skewness of the SECT distribution is 0.57%, and A) −0.19%, B) −0.56%, C) −0.29% and D) −0.07% for DECT methods respectively. Conclusion: The here presented DECT methods B, C and D outperform the commonly used SECT stoichiometric calibration. These methods predict SPR accurately without a bias and within ± 1.2% (68th percentile). This indicates that DECT potentially improves accuracy of range predictions in proton therapy. A validation of these findings using clinical CT images of real tissues is necessary.

  19. Comparison of x ray computed tomography number to proton relative linear stopping power conversion functions using a standard phantom.

    Science.gov (United States)

    Moyers, M F

    2014-06-01

    Adequate evaluation of the results from multi-institutional trials involving light ion beam treatments requires consideration of the planning margins applied to both targets and organs at risk. A major uncertainty that affects the size of these margins is the conversion of x ray computed tomography numbers (XCTNs) to relative linear stopping powers (RLSPs). Various facilities engaged in multi-institutional clinical trials involving proton beams have been applying significantly different margins in their patient planning. This study was performed to determine the variance in the conversion functions used at proton facilities in the U.S.A. wishing to participate in National Cancer Institute sponsored clinical trials. A simplified method of determining the conversion function was developed using a standard phantom containing only water and aluminum. The new method was based on the premise that all scanners have their XCTNs for air and water calibrated daily to constant values but that the XCTNs for high density/high atomic number materials are variable with different scanning conditions. The standard phantom was taken to 10 different proton facilities and scanned with the local protocols resulting in 14 derived conversion functions which were compared to the conversion functions used at the local facilities. For tissues within ±300 XCTN of water, all facility functions produced converted RLSP values within ±6% of the values produced by the standard function and within 8% of the values from any other facility's function. For XCTNs corresponding to lung tissue, converted RLSP values differed by as great as ±8% from the standard and up to 16% from the values of other facilities. For XCTNs corresponding to low-density immobilization foam, the maximum to minimum values differed by as much as 40%. The new method greatly simplifies determination of the conversion function, reduces ambiguity, and in the future could promote standardization between facilities. Although it

  20. TU-FG-BRB-01: Dual Energy CT Proton Stopping Power Ratio Calibration and Validation with Animal Tissues

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Y; Yin, L; Ainsley, C; McDonough, J; Solberg, T; Lin, A; Teo, B [University of Pennsylvania, Philadelphia, PA (United States)

    2016-06-15

    Purpose: The conversion of Hounsfield Unit (HU) to proton stopping power ratio (SPR) is a main source of uncertainty in proton therapy. In this study, the SPRs of animal tissues were measured and compared with prediction from dual energy CT (DECT) and single energy CT (SECT) calibrations. Methods: A stoichiometric calibration method for DECT was applied to predict the SPR using CT images acquired at 80 kVp and 140 kVp. The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the SPRs of the materials. Tissue surrogates with known chemical compositions were used for calibration, and animal tissues (pig brain, liver, kidney; veal shank, muscle) were used for validation. The materials were irradiated with proton pencil beams, and SPRs were deduced from the residual proton range measured using a multi-layer ion chamber device. In addition, Gafchromic EBT3 films were used to measure the distal dose profiles after irradiation through the tissue samples and compared with those calculated by the treatment planning system using both DECT and SECT predicted SPRs. Results: The differences in SPR between DECT prediction and measurement were −0.31±0.36% for bone, 0.47±0.42% for brain, 0.67±0.15% for liver, 0.51±0.52% for kidney, and −0.96±0.15% for muscle. The corresponding results using SECT were 3.1±0.12%, 1.90±0.45%, −0.66±0.11%, 2.33±0.21%, and −1.70±0.17%. In the film measurements, average distances between film and calculated distal dose profiles were 0.35±0.12 mm for DECT calibration and −1.22±0.12 mm for SECT calibration for a beam with a range of 15.79 cm. Conclusion: Our study indicates that DECT is superior to SECT for proton SPR prediction and has the potential to reduce the range uncertainty to less than 2%. DECT may permit the use of tighter distal and proximal range uncertainty margins for treatment, thereby increasing the precision of proton therapy.

  1. Beam dosimetry in high-power electron accelerators

    International Nuclear Information System (INIS)

    Popov, V.N.; Zhitomirskii, B.M.; Ermakov, A.N.; Terebilin, A.V.; Stryukov, V.A.

    1987-01-01

    In order to evaluate beam utilization efficiency, measure the radiation yield, and determine the cost effectiveness of the new technologies, it is necessary to know the radiation power of the electron beam absorbed by the reacting medium. To measure the electron-beam power the authors designed, built, and tested a radiation detector combining a Faraday cylinder with a continuous-flow calorimeter. The construction of the detector is shown. The radiation detector was tested on a number of electron accelerators. The beam-power and mean-electron-energy measurement results for the LUE-8M accelerator with 8 MeV maximum electron energy are given

  2. Material elemental decomposition in dual and multi-energy CT via a sparsity-dictionary approach for proton stopping power ratio calculation.

    Science.gov (United States)

    Shen, Chenyang; Li, Bin; Chen, Liyuan; Yang, Ming; Lou, Yifei; Jia, Xun

    2018-04-01

    Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately determine SPR. One method to further improve accuracy is to incorporate prior knowledge on human tissue composition through a dictionary approach. In addition, it is also suggested that using CT images with multiple (more than two) energy channels, i.e., multi-energy CT (MECT), can further improve accuracy. In this paper, we proposed a sparse dictionary-based method to convert CT numbers of DECT or MECT to elemental composition (EC) and relative electron density (rED) for SPR computation. A dictionary was constructed to include materials generated based on human tissues of known compositions. For a voxel with CT numbers of different energy channels, its EC and rED are determined subject to a constraint that the resulting EC is a linear non-negative combination of only a few tissues in the dictionary. We formulated this as a non-convex optimization problem. A novel algorithm was designed to solve the problem. The proposed method has a unified structure to handle both DECT and MECT with different number of channels. We tested our method in both simulation and experimental studies. Average errors of SPR in experimental studies were 0.70% in DECT, 0.53% in MECT with three energy channels, and 0.45% in MECT with four channels. We also studied the impact of parameter values and established appropriate parameter values for our method. The proposed method can accurately calculate SPR using DECT and MECT. The results suggest that using more energy channels may improve the SPR estimation accuracy. © 2018 American Association of Physicists in Medicine.

  3. SU-E-T-161: Characterization and Validation of CT Simulator Hounsfield Units to Relative Stopping Power Values for Proton Treatment Planning

    International Nuclear Information System (INIS)

    Schnell, E; Ahmad, S; De La Fuente Herman, T

    2015-01-01

    Purpose: To develop a calibration curve that includes and minimizes the variations of Hounsfield Unit (HU) from a CT scanner to Relative Stopping Power (RSP) of tissues along the proton beam path. The variations are due to scanner and proton energy, technique, phantom size and placement, and tissue arrangement. Methods: A CIRS 062 M phantom with 10 plugs of known relative electron density (RED) was scanned through a 16 slice GE Discovery CT Simulator scanner. Three setup combinations of plug distributions and techniques clinically implemented for five treatment regions were scanned with energies of 100, 120, and 140 kV. Volumetric HU values were measured for each plug and scan. The RSP values derived through the Bethe-Bloch formula are currently being verified with parallel-plate ionization chamber measurements in water using 80, 150, and 225 MeV proton beam. Typical treatment plans for treatment regions of brain, head-&-neck, chest, abdomen, and pelvis are being planned and dose delivered will be compared with film and Optically Stimulated Luminescence (OSL) measurements. Results: Percentage variations were determined for each variable. For tissues close to water, variations were <1% from any given parameter. Tissues far from water equivalence (lung and bone) showed the greatest sensitivity to change (7.4% maximum) with scanner energy and up to 5.3% with positioning of the phantom. No major variations were observed for proton energies within the treatment range. Conclusion: When deriving a calibration curve, attention should be placed to low and high HU values. A thorough verification process of calculated vs. water-phantom measured RSP values at different proton energies, followed by dose validation of planned vs. measured doses in phantom with film and OSL detectors are currently being undertaken

  4. Power electronics converters for wind turbine systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Liserre, Marco; Ma, Ke

    2011-01-01

    The steady growth of installed wind power which reached 200 GW capacity in 2010, together with the up-scaling of the single wind turbine power capability - 7 MW’s has been announced by manufacturers - has pushed the research and development of power converters towards full scale power conversion,...

  5. The future of electronic power processing and conversion

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Consoli, A.; Ferreira, J.A.

    2005-01-01

    . - A large penetration of power electronics into power systems will happen within the next 25-30 years. The main transmission grid will not be affected. The power electronics development will be in distributed generation and in the loads. - The success of the integrated starter/generator, hybrid or electric...... cars depends on political decisions more than on technological advances. However, the success of a recent Japanese hybrid car and the cost of oil could trigger the critical momentum for large-scale use of power electronics in automotive applications. - We are moving toward standardized power supply...

  6. Trends in Power Electronics and Control of Renewable Energy Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Iov, Florin; Kerekes, Tamas

    2010-01-01

    term) based energy sources to renewable energy sources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss trends of the most emerging renewable energy sources, wind energy and photovoltaics, which...... by means of power electronics are changing the future electrical infrastructure but also contributes steadily more to non-carbon based electricity production. Most focus is on the power electronics technologies used. In the case of photovoltaics transformer-less systems are discussed as they have...

  7. Hydrogen/oxygen injection stopping method for nuclear power plant and emergent hydrogen/oxygen injection device

    International Nuclear Information System (INIS)

    Ishida, Ryoichi; Ota, Masamoto; Takagi, Jun-ichi; Hirose, Yuki

    1998-01-01

    The present invention provides a device for suppressing increase of electroconductivity of reactor water during operation of a BWR type reactor, upon occurrence of reactor scram of the plant or upon stopping of hydrogen/oxygen injection due to emergent stoppage of an injection device so as not to deteriorate the integrity of a gas waste processing system upon occurrence of scram. Namely, when injection of hydrogen/oxygen is stopped during plant operation, the injection amount of hydrogen is reduced gradually. Subsequently, injection of hydrogen is stopped. With such procedures, the increase of electroconductivity of reactor water can be suppressed upon stoppage of hydrogen injection. When injection of hydrogen/oxygen is stopped upon shut down of the plant, the amount of hydrogen injection is changed depending on the change of the feedwater flow rate, and then the plant is shut down while keeping hydrogen concentration of feedwater to a predetermined value. With such procedures, increase of the reactor water electroconductivity can be suppressed upon stoppage of hydrogen injection. Upon emergent stoppage of the hydrogen/oxygen injection device, an emergent hydrogen/oxygen injection device is actuated to continue the injection of hydrogen/oxygen. With such procedures, elevation of reactor water electroconductivity can be suppressed. (I.S.)

  8. A Review of Power Electronics Based Microgrids

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Guerrero, Josep M.; Blaabjerg, Frede

    2012-01-01

    The increased penetration of Distributed Energy Resources (DER) is challenging the entire architecture of conventional electrical power system. Microgrid paradigm, featuring higher flexibility and reliability, becomes an attractive candidate for the future power grid. In this paper, an overview o...

  9. An Organic Mixed Ion-Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  10. An Organic Mixed Ion–Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  11. Electronic DC transformer with high power density

    NARCIS (Netherlands)

    Pavlovský, M.

    2006-01-01

    This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

  12. A Thermoelectric Generation System and Its Power Electronics Stage

    DEFF Research Database (Denmark)

    Gao, Junling; Sun, Kai; Ni, Longxian

    2012-01-01

    stage and signal-conditioning circuits of the load, including DC–DC conversion, the maximum power point tracking (MPPT) controller, and other power management controllers. In this paper, a survey of existing power electronics designs for TEG systems is presented first. Second, a flat, wall-like TEG...... system consisting of 32 modules is experimentally optimized, and the improved power parameters are tested. Power-conditioning circuitry based on an interleaved boost DC–DC converter is then developed for the TEG system in terms of the tested power specification. The power electronics design features...... a combined control scheme with an MPPT and a constant output voltage as well as the low-voltage and high-current output characteristics of the TEG system. The experimental results of the TEG system with the power electronics stage and with purely resistive loads are compared. The comparisons verify...

  13. Conceptual survey of Generators and Power Electronics for Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, L.H.; Helle, L.; Blaabjerg, F.; Ritchie, E.; Munk-Nielsen, S.; Bindner, H.; Soerensen, P.; Bak-Jensen, B.

    2001-12-01

    This report presents a survey on generator concepts and power electronic concepts for wind turbines. The report is aimed as a tool for decision-makers and development people with respect to wind turbine manufactures, utilities, and independent system operators as well as manufactures of generators and power electronics. The survey is focused on the electric development of wind turbines and it yields an overview on: State of the art on generators and power electronics; future concepts and technologies within generators and power electronics; market needs in the shape of requirements to the grid connection, and; consistent system solutions, plus an evaluation of these seen in the prospect of market needs. This survey on of generator and power electronic concepts was carried out in co-operation between Aalborg University and Risoe National Laboratory in the scope of the research programme Electric Design and Control. (au)

  14. Conceptual survey of generators and power electronics for wind turbines

    DEFF Research Database (Denmark)

    Hansen, L.H.; Helle, L.; Blaabjerg, F.

    2002-01-01

    This report presents a survey on generator concepts and power electronic concepts for wind turbines. The report is aimed as a tool for decision-makers and development people with respect to wind turbine manufactures, utilities, and independent systemoperators as well as manufactures of generators...... and power electronics. The survey is focused on the electric development of wind turbines and it yields an overview on: - State of the art on generators and power electronics. - future concepts andtechnologies within generators and power electronics. - market needs in the shape of requirements to the grid...... connection, and - consistent system solutions, plus an evaluation of these seen in the prospect of market needs. This survey on of generatorand power electronic concepts was carried out in co-operation between Aalborg University and Risø National Laboratory in the scope of the research programme Electric...

  15. High-Power Electron Accelerators for Space (and other) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-23

    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  16. Power Electronics and Reliability in Renewable Energy Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke; Zhou, Dao

    2012-01-01

    Power Electronics are needed in almost all kind of renewable energy systems. It is used both for controlling the renewable source and also for interfacing to the load, which can be grid-connected or working in stand-alone mode. More and more efforts are put into making renewable energy systems...... better in terms of reliability in order to ensure a high availability of the power sources, in this case the knowledge of mission profile of a certain application is crucial for the reliability evaluation/design of power electronics. In this paper an overview on the power electronic circuits behind...... the most common converter configurations for wind turbine and photovoltaic is done. Next different aspects of improving the system reliability are mapped. Further on examples of how to control the chip temperature in different power electronic configurations as well as operation modes for wind power...

  17. Power Electronics for Renewable Energy Systems - Status and Trends

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke; Yang, Yongheng

    2014-01-01

    electronics in generation, transmission/distribution and end-user application, together with advanced controls, can pave the way for renewable energy resources. In view of this, some of the most promising renewable candidates like wind power and photovoltaic, which are becoming a significant part...... in the electricity production, are explored in this paper. Issues like technology demands, power converter topologies, and control structures are addressed. Some special focuses are also paid on the emerging trends in power electronics development for those systems....

  18. Power electronics applied to industrial systems and transports

    CERN Document Server

    Patin, Nicolas

    2015-01-01

    If the operation of electronic components switching scheme to reduce congestion and losses (in power converters in general and switching power supplies in particular), it also generates electromagnetic type of pollution in its immediate environment. Power Electronics for Industry and Transport, Volume 4 is devoted to electromagnetic compatibility. It presents the sources of disturbance and the square wave signal, spectral modeling generic perturbation. Disturbances propagation mechanisms called ""lumped"" by couplings such as a common impedance, a parasitic capacitance or a mutual and ""dis

  19. A Reliability-Oriented Design Method for Power Electronic Converters

    DEFF Research Database (Denmark)

    Wang, Huai; Zhou, Dao; Blaabjerg, Frede

    2013-01-01

    Reliability is a crucial performance indicator of power electronic systems in terms of availability, mission accomplishment and life cycle cost. A paradigm shift in the research on reliability of power electronics is going on from simple handbook based calculations (e.g. models in MIL-HDBK-217F h...... and reliability prediction models are provided. A case study on a 2.3 MW wind power converter is discussed with emphasis on the reliability critical component IGBT modules....

  20. Integrated power electronic converters and digital control

    CERN Document Server

    Emadi, Ali; Nie, Zhong

    2009-01-01

    Non-isolated DC-DC ConvertersBuck ConverterBoost ConverterBuck-Boost ConverterIsolated DC-DC ConvertersFlyback ConverterForward ConverterPush-Pull ConverterFull-Bridge ConverterHalf-Bridge ConverterPower Factor CorrectionConcept of PFCGeneral Classification of PFC CircuitsHigh Switching Frequency Topologies for PFCApplication of PFC in Advanced Motor DrivesIntegrated Switched-Mode Power ConvertersSwitched-Mode Power SuppliesThe Concept of Integrated ConverterDefinition of Integrated Switched-Mode Power Supplies (ISMPS)Boost-Type Integrated TopologiesGeneral Structure of Boost-Type Integrated T

  1. Power Electronics for the Next Generation Wind Turbine System

    DEFF Research Database (Denmark)

    Ma, Ke

    generation unit, are becoming crucial in the wind turbine system. The objective of this project is to study the power electronics technology used for the next generation wind turbines. Some emerging challenges as well as potentials like the cost of energy and reliability are going to be addressed. First...... conversion is pushed to multi-MW level with high power density requirement. It has also been revealed that thermal stress in the power semiconductors is closely related to many determining factors in the wind power application like the reliability, cost, power density, etc. therefore it is an important......The wind power generation has been steadily growing both for the total installed capacity and for the individual turbine size. Due to much more significant impacts to the power grid, the power electronics, which can change the behavior of wind turbines from an unregulated power source to an active...

  2. Power electronics applied to industrial systems and transports

    CERN Document Server

    Patin, Nicolas

    2015-01-01

    Some power electronic converters are specifically designed to power equipment under a smoothed DC voltage. Therefore, the filtering part necessarily involves the use of auxiliary passive components (inductors and capacitors). This book deals with technical aspects such as classical separation between isolated and non-isolated power supplies, and soft switching through a special converter. It addresses the problem of regulating the output voltage of the switching power supplies in terms of modeling and obtaining transfer of SMPS functions.Power Electronics for Industry and Transport, Volume 3,

  3. High Power Density Power Electronic Converters for Large Wind Turbines

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk

    . For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these turbines operate under harsh operating conditions. In order to select a high power density and reliability......In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids...... VSC solution for wind turbines, first, the VSC topology and the switch technology to be employed should be specified such that the highest possible power density and reliability are to be attained. Then, this qualitative approach should be complemented with the power density and reliability...

  4. SU-F-T-136: Breath Hold Lung Phantom Study in Using CT Density Versus Relative Stopping Power Ratio for Proton Pencil Beam Scanning System

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J; Wu, H; Rosen, L [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2016-06-15

    Purpose: To evaluate mass density effects of CT conversion table and its variation in current treatment planning system of spot scanning proton beam using an IROC proton lung phantom for this study. Methods: A proton lung phantom study was acquired to Imaging and Radiation Oncology Core Houston (IROC) Quality Assurance Center. Inside the lung phantom, GAF Chromic films and couples of thermal luminescent dosimeter (TLD) capsules embedded in specified PTV and adjacent structures to monitor delivered dosage and 3D dose distribution profiles. Various material such as cork (Lung), blue water (heart), Techron HPV (ribs) and organic material of balsa wood and cork as dosimetry inserts within phantom of solid water (soft tissue). Relative stopping power (RLSP) values were provided. Our treatment planning system (TPS) doesn’t require SP instead relative density was converted relative to water. However lung phantom was irradiated by planning with density override and the results were compared with IROC measurements. The second attempt was conducted without density override and compared with IROC’s. Results: The higher passing rate of imaging and measurement results of the lung phantom irradiation met the criteria by IROC without density override. The film at coronal plane was found to be shift due to inclined cylinder insertion. The converted CT density worked as expected to correlate relative stopping power. Conclusion: The proton lung phantom provided by IROC is a useful tool to qualify our commissioned proton pencil beam delivery with TPS within reliable confidence. The relative mass stopping power ratios of materials were converted from the relative physical density relative to water and the results were satisfied.

  5. Relativistic theory of stopping for heavy ions

    International Nuclear Information System (INIS)

    Lindhard, J.; So/rensen, A.H.

    1996-01-01

    We calculate the electronic stopping power and the corresponding straggling for ions of arbitrary charge number, penetrating matter at any relativistic energy. The stopping powers are calculated by a simple method. Its starting point is the deviation of the precise theory from first-order quantum perturbation. We show that this deviation can be expressed in terms of the transport cross section, σ tr , for scattering of a free electron by the ion. In the nonrelativistic case the deviation is precisely the Bloch correction to Bethe close-quote s formula; we look into the nonrelativistic case in order to clarify both some features of our method and a seeming paradox in Rutherford scattering. The corresponding relativistic correction is obtained from σ tr for scattering of a Dirac electron in the ion potential. Here, the major practical advantage of the method shows up; we need not find the scattering distribution, but merely a single quantity, σ tr , determined by differences of successive phase shifts. For a point nucleus our results improve and extend those of Ahlen. Our final results, however, are based on atomic nuclei with standard radii. Thereby, the stopping is changed substantially already for moderate values of γ=(1-v 2 /c 2 ) -1/2 . An asymptotic saturation in stopping is obtained. Because of finite nuclear size, recoil corrections remain negligible at all energies. The average square fluctuation in energy loss is calculated as a simple fluctuation cross section for a free electron. The fluctuation in the relativistic case is generally larger than that of the perturbation formula, by a factor of ∼2 endash 3 for heavy ions. But the finite nuclear radius leads to a strong reduction at high energies and the elimination of the factor γ 2 belonging to point nuclei. copyright 1996 The American Physical Society

  6. Palm Power Free-Piston Stirling Engine Control Electronics

    Science.gov (United States)

    Keiter, Douglas E.; Holliday, Ezekiel

    2007-01-01

    A prototype 35We, JP-8 fueled, soldier-wearable power system for the DARPA Palm Power program has been developed and tested by Sunpower. A hermetically-sealed 42We Sunpower Free-Piston Stirling Engine (FPSE) with integral linear alternator is the prime mover for this system. To maximize system efficiency over a broad range of output power, a non-dissipative, highly efficient electronic control system which modulates engine output power by varying piston stroke and converts the AC output voltage of the FPSE into 28Vdc for the Palm Power end user, has been designed and demonstrated as an integral component of the Palm Power system. This paper reviews the current status and progress made in developing the control electronics for the Palm Power system, in addition to describing the operation and demonstrated performance of the engine controller in the context of the current JP-8 fueled Palm Power system.

  7. A Multi-Functional Power Electronic Converter in Distributed Generation Power Systems

    DEFF Research Database (Denmark)

    Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

    2005-01-01

    of the converter interfacing a wind power generation unit is also given. The power electronic interface performs the optimal operation in the wind turbine system to extract the maximum wind power, while it also plays a key role in a hybrid compensation system that consists of the active power electronic converter......This paper presents a power electronic converter which is used as an interface for a distributed generation unit/energy storage device, and also functioned as an active power compensator in a hybrid compensation system. The operation and control of the converter have been described. An example...... and passive filters connected to each distorting load or distributed generation (DG) unit. The passive filters are distributely located to remove major harmonics and provide reactive power compensation. The active power electronic filter corrects the system unbalance, removes the remaining harmonic components...

  8. Deep Space Cryogenic Power Electronics, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Technology Application, Inc. (TAI) is proposing to demonstrate feasibility of implementing silicon germanium (SiGe) strained-gate technology in the power...

  9. Power electronic modules design and manufacture

    CERN Document Server

    Sheng, William W

    2004-01-01

    IntroductionSelection ProcedureMaterialsInsulating Substrate and MetallizationBase PlateBonding MaterialPower Interconnection and TerminalEncapsulantPlastic Case and Cover Manufacturing of Power IGBT ModulesManufacturing Process Process Control/Long-Term ReliabilityManufacturing FacilitiesManufacturing Flow Charts DesignThermal ManagementCircuit PartitioningDesign Guidelines and ConsiderationsThermal Results of Different Samples

  10. Miniaturization, Packaging, and Thermal Analysis of Power Electronics Modules

    OpenAIRE

    Lostetter, Alexander B.

    1998-01-01

    High power circuits, those involving high levels of voltages and currents to produce several kilowatts of power, would possess an optimized efficiency when driven at high frequencies (on the order of MHz). Such an approach would greatly reduce the size of capacitive and magnetic components, and thus ultimately reduce the cost of the power electronic circuits. The problem with this strategy in conventional packaging, however, is that at high frequencies, interconnects between the power devic...

  11. Power electronic converters PWM strategies and current control techniques

    CERN Document Server

    Monmasson, Eric

    2013-01-01

    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  12. The Energy Processing by Power Electronics and its Impact on Power Quality

    Directory of Open Access Journals (Sweden)

    J.E. Rocha

    2012-11-01

    Full Text Available This paper discusses the electrical architectures adopted in wind turbines and its impact on the harmonic flux at the connected electric network. The integration of wind electric generators with the power grid needs energy processing by power electronics. It shows that different types of wind turbine generator systems use different types of electronic converters. This work provides a discussion on harmonic distortion taking place on the generator side, as well as in the power grid side. Keywords: grid connection, harmonic distortion, power electronics and converters, wind energy conversion systems, wind power, wind technology, wind turbines

  13. Microwave and RF vacuum electronic power sources

    CERN Document Server

    Carter, Richard G

    2018-01-01

    Do you design and build vacuum electron devices, or work with the systems that use them? Quickly develop a solid understanding of how these devices work with this authoritative guide, written by an author with over fifty years of experience in the field. Rigorous in its approach, it focuses on the theory and design of commercially significant types of gridded, linear-beam, crossed-field and fast-wave tubes. Essential components such as waveguides, resonators, slow-wave structures, electron guns, beams, magnets and collectors are also covered, as well as the integration and reliable operation of devices in microwave and RF systems. Complex mathematical analysis is kept to a minimum, and Mathcad worksheets supporting the book online aid understanding of key concepts and connect the theory with practice. Including coverage of primary sources and current research trends, this is essential reading for researchers, practitioners and graduate students working on vacuum electron devices.

  14. Future on Power Electronics for Wind Turbine Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke

    2013-01-01

    networks and more and more wind power stations, acting as power plants, are connected directly to the transmission networks. As the grid penetration and power level of the wind turbines increase steadily, the wind power starts to have significant impacts to the power grid system. Therefore, more advanced...... generators, power electronic systems, and control solutions have to be introduced to improve the characteristics of the wind power plant and make it more suitable to be integrated into the power grid. Meanwhile, there are also some emerging technology challenges, which need to be further clarified......Wind power is still the most promising renewable energy in the year of 2013. The wind turbine system (WTS) started with a few tens of kilowatt power in the 1980s. Now, multimegawatt wind turbines are widely installed even up to 6-8 MW. There is a widespread use of wind turbines in the distribution...

  15. Modeling and Verification of Dependable Electronic Power System Architecture

    Science.gov (United States)

    Yuan, Ling; Fan, Ping; Zhang, Xiao-fang

    The electronic power system can be viewed as a system composed of a set of concurrently interacting subsystems to generate, transmit, and distribute electric power. The complex interaction among sub-systems makes the design of electronic power system complicated. Furthermore, in order to guarantee the safe generation and distribution of electronic power, the fault tolerant mechanisms are incorporated in the system design to satisfy high reliability requirements. As a result, the incorporation makes the design of such system more complicated. We propose a dependable electronic power system architecture, which can provide a generic framework to guide the development of electronic power system to ease the development complexity. In order to provide common idioms and patterns to the system *designers, we formally model the electronic power system architecture by using the PVS formal language. Based on the PVS model of this system architecture, we formally verify the fault tolerant properties of the system architecture by using the PVS theorem prover, which can guarantee that the system architecture can satisfy high reliability requirements.

  16. Renewable Energy Systems in the Power Electronics Curriculum

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe; Teodorescu, Remus

    2005-01-01

    of the most important area is renewable energy systems. This paper will discuss the basic courses for the power electronics curriculum. It will also discuss how to teach power electronic systems efficiently through a projectoriented and problem-based learning approach with Aalborg University in Denmark...... as a full-scale example. Different project examples will be given as well as important laboratories for adjustable speed drives and renewable energy systems which are used at the university are described.......Power Electronics is still an emerging technology and its applications are increasing. The primary function is to convert electrical energy from one stage to another and it is used in many different applications. The power electronics curriculum is multidisciplinary covering fields like devices...

  17. A new electronic circuit for NIM rack power supply

    International Nuclear Information System (INIS)

    Toledo, Fabio de; Domienikan, Claudio; Zahn, Guilherme S.

    2013-01-01

    A new and useful electronic circuit designed to substitute the old power supply of IPEN model PM 1212 Nuclear Instrument Modules (NIM) racks is presented. Originally, these NIM racks were projected by IPEN workshop at 1974 to be used in nuclear research laboratories. The PM1212 provided mounting space and power sources for up to 12 standard nuclear electronic modules and power supply regulated DC voltages of ±24V (2A), ±12V (4A) and unregulated AC 117V (0.5A). Currently, several of these NIM racks are not in use because the electronic components of the original design have become obsolete and are no longer manufactured. The new electronic circuit provides the same original voltages adjusted in the single circuit and, additionally, ±6V. The new power supply was designed and constructed at IPEN-CNEN/SP by employing modern national components and expertise. (author)

  18. Power electronic converter systems for direct drive renewable energy applications

    DEFF Research Database (Denmark)

    Chen, Zhe

    2013-01-01

    This chapter presents power electronic conversion systems for wind and marine energy generation applications, in particular, direct drive generator energy conversion systems. Various topologies are presented and system design optimization and reliability are briefly discussed....

  19. Power System Electronics (PSE) Development for SmallSat Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — We develop a modular Power System Electronics (PSE) that is reliable, efficient, and flexible to meet the Goddard Modular Smallsat Architecture (GMSA) challenge....

  20. A new electronic circuit for NIM rack power supply

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Fabio de; Domienikan, Claudio; Zahn, Guilherme S., E-mail: fatoledo@ipen.br, E-mail: clanikan@ipen.br, E-mail: gzahn@ipen.br [Intituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2013-07-01

    A new and useful electronic circuit designed to substitute the old power supply of IPEN model PM 1212 Nuclear Instrument Modules (NIM) racks is presented. Originally, these NIM racks were projected by IPEN workshop at 1974 to be used in nuclear research laboratories. The PM1212 provided mounting space and power sources for up to 12 standard nuclear electronic modules and power supply regulated DC voltages of ±24V (2A), ±12V (4A) and unregulated AC 117V (0.5A). Currently, several of these NIM racks are not in use because the electronic components of the original design have become obsolete and are no longer manufactured. The new electronic circuit provides the same original voltages adjusted in the single circuit and, additionally, ±6V. The new power supply was designed and constructed at IPEN-CNEN/SP by employing modern national components and expertise. (author)

  1. Balancing particle absorption with structural support of the muon beam stop in muons-to-electrons experimental chamber

    Energy Technology Data Exchange (ETDEWEB)

    Majewski, Ryan [Northern Illinois Univ., DeKalb, IL (United States)

    2013-01-01

    The Mu2e experiment at Fermi National Accelerator Laboratory is seeking a full conversion from muon to electron. The design for Mu2e is based off MECO, another proposed experiment that sought a full conversion from muon to electron at Brookhaven National Laboratory in the 1990s. Mu2e will provide sensitivity that is four times the sensitivity of the previous experiment, SINDRUM II. Discovering muon to electron conversions could help explain physics beyond the standard model of the particle physics.

  2. Photovoltaic Systems Are With Power Electronics

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    In these days of increasing environmental concern, governments and the scientific community work to maximize the use of renewable energy resources. There is a growing recognition of the valuable role solar power can play in reducing pollution - particularly in the effort to stabilize the carbon d...

  3. New experimental stopping power data of 4He, 16O, 40Ar, 48Ca and 84Kr projectiles in different solid materials

    Science.gov (United States)

    Trzaska, W. H.; Knyazheva, G. N.; Perkowski, J.; Andrzejewski, J.; Khlebnikov, S. V.; Kozulin, E. M.; Malkiewicz, T.; Mutterer, M.; Savelieva, E. O.

    2018-03-01

    New experimental data on energy loss of 4He, 16O, 40Ar, 48Ca and 84Kr ions in thin, self-supporting foils of C, Al, Ni, Ag, Lu, Au, Pb and Th are presented. The measurements, using the TOF-E method, were done in a very broad energy range around the stopping power maximum; typically from 0.1 to 11 MeV/u. When available, the extracted stopping power values are compared with the previously published data. The overall agreement is good although a fair comparison is difficult as the covered energy range is much larger than in previous measurements. The small error bars and a broad coverage allowed us to test the predictions of theoretical codes: PASS, CasP, and semi-empirical programs: SRIM, LET, MSTAR, and the Hubert table predictions. The deviations of PASS predictions from the experimental data do not exceed 20% for all the measured combinations. CasP predictions are within 15% from the data for heavier ions but diverge up to 40% for lighter ions. Semi-empirical approaches, including SRIM, deviate from the experimental data by less than 5% for the regions already covered by previous experiments but err by about 10-20% for the ion/target combinations that were not measured before: Ca in Lu as well as Kr in Lu, Pb, and Th.

  4. International Conference on Power Electronics and Renewable Energy Systems

    CERN Document Server

    Suresh, L; Dash, Subhransu; Panigrahi, Bijaya

    2015-01-01

    The book is a collection of high-quality peer-reviewed research papers presented in Proceedings of International Conference on Power Electronics and Renewable Energy Systems (ICPERES 2014) held at Rajalakshmi Engineering College, Chennai, India. These research papers provide the latest developments in the broad area of Power Electronics and Renewable Energy. The book discusses wide variety of industrial, engineering and scientific applications of the emerging techniques. It presents invited papers from the inventors/originators of new applications and advanced technologies.

  5. Advanced and intelligent control in power electronics and drives

    CERN Document Server

    Blaabjerg, Frede; Rodríguez, José

    2014-01-01

    Power electronics and variable frequency drives are continuously developing multidisciplinary fields in electrical engineering, and it is practically not possible to write a book covering the entire area by one individual specialist. Especially by taking account the recent fast development in the neighboring fields like control theory, computational intelligence and signal processing, which all strongly influence new solutions in control of power electronics and drives. Therefore, this book is written by individual key specialist working on the area of modern advanced control methods which penetrates current implementation of power converters and drives. Although some of the presented methods are still not adopted by industry, they create new solutions with high further research and application potential. The material of the book is presented in the following three parts: Part I: Advanced Power Electronic Control in Renewable Energy Sources (Chapters 1-4), Part II: Predictive Control of Power Converters and D...

  6. Poster power brings together electronics community

    CERN Multimedia

    2006-01-01

    An 'Electronics at CERN' poster session was displayed on the mezzanine in building 500 for two days from 30 November. The display consisted of 20 posters and brought together a wide range of electronic projects designed and assembled by CERN teams and other collaborators involved in the building of the LHC. This was the first time this event had been held. As its organiser John Evans (IT/DES) explained, 'the idea came from the experience of attending conferences outside CERN, where you may find projects from CERN you didn't know about. It's nice to bring them together so we can all benefit from the efforts made.' The work on show spanned different departments and experiments, ranging from microelectronics to equipment designed for giant magnets. The invited audience was equally broad and included engineers, physicists as well as the electronics community at CERN. An informal gathering of all the exhibitors also offered an opportunity to view and discuss the work over a cup of coffee. 'The poster session acts...

  7. Standalone, battery powered radiation monitors for accelerator electronics

    CERN Document Server

    Wijnands, T; Spiezia, G

    2009-01-01

    A technical description of the design of a new type of radiation monitors is given. The key point in the design is the low power consumption inferior to 17 mW in radiation sensing mode and inferior to 0.3 mW in standby mode. The radiation monitors can operate without any external power or signal cabling and measure and store radiation data for a maximum period of 800 days. To read the radiation data, a standard PC can be connected via a USB interface to the device at any time. Only a few seconds are required to read out a single monitor. This makes it possible to survey a large network of monitoring devices in a short period of time, for example during a stop of the accelerator.

  8. Power electronics solution to dust emissions from thermal power plants

    Directory of Open Access Journals (Sweden)

    Vukosavić Slobodan

    2010-01-01

    Full Text Available Thermal power stations emit significant amounts of fly ash and ultra fine particles into the atmosphere. Electrostatic precipitators (ESP or electro filters remove flying ashes and fine particles from the flue gas before passing the gas into the chimney. Maximum allowable value of dust is 50 mg/m3 and it requires that the efficiency of the ESPs better than 99 %, which calls for an increase of active surface of the electrodes, hence increasing the filter volume and the weight of steel used for the filter. In previous decades, electrostatic precipitators in thermal power plants were fed by thyristor controlled, single phase fed devices having a high degree of reliability, but with a relatively low collection efficiency, hence requiring large effective surface of the collection plates and a large weight of steel construction in order to achieve the prescribed emission limits. Collection efficiency and energy efficiency of the electrostatic precipitator can be increased by applying high frequency high voltage power supply (HF HV. Electrical engineering faculty of the University of Belgrade (ETF has developed technology and HF HV equipment for the ESP power supply. This solution was subjected to extensive experimental investigation at TE Morava from 2008 to 2010. High frequency power supply is proven to reduce emission two times in controlled conditions while increasing energy efficiency of the precipitator, compared to the conventional thyristor controlled 50Hz supply. Two high frequency high voltage unit AR70/1000 with parameters 70 kV and 1000 mA are installed at TE Morava and thoroughly testes. It was found that the HF HV power supply of the ESP at TE Morava increases collection efficiency so that emission of fine particles and flying ashes are halved, brought down to only 50 % of the emissions encountered with conventional 50 Hz thyristor driven power supplies. On the basis of this study, conclusion is drawn that the equipment comprising HF HV

  9. Recent Operating Experience involving Power Electronics Failure in Korea Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lee, Jaedo

    2015-01-01

    Recently, modern power electronics devices for electrical component were steadily increased in electrical systems which used for main power control and protection. To upgrade the system reliability we recommended the redundancy for electrical equipment trip system. The past several years, Korean Nuclear power plants have changed the electrical control and protection systems (Auto Voltage Regulator, Power Protection Relay) for main generator and main power protection relay systems. In this paper we deal with operating experience involving modern solid state power electronics failure in Korean nuclear power plants. One of the failures we will discuss the degraded phenomenon of power electronics device for CEDMCS(Control Element Drive Mechanism Control System). As the result of the failure we concerned about the modification for trip source of main generator excitation systems and others. We present an interesting issue for modern solid state devices (IGBT, Thyristors). (authors)

  10. Recent progress in power electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Yasuhiko; Yatsuo, Tsutomu

    1987-02-01

    Recent progress and future trends of power semiconductor devices (especially with respect to motor speed control) were described. Conventional discrete devices such as thyristors, bipolar transistors, unipolar transistors and Bi-MOS devices were referenced to. Reference was also made to High Voltage ICs. There has been steady progress with each of these power devices in current carrying capability, voltage blocking capability and switching speed. The Bipolar-MOS integreated device and the High Voltage IC are particularly interesting because their abilities and performances are much enhanced by skillful combination with conventional discrete devices. However, no one device meets all the needs, and it will always be necessary to select the right device for a specific task. (11 figs, 35 refs)

  11. Fault tolerant embedded computers and power electronics for nuclear robotics

    International Nuclear Information System (INIS)

    Giraud, A.; Robiolle, M.

    1995-01-01

    For requirements of nuclear industries, it is necessary to use embedded rad-tolerant electronics and high-level safety. In this paper, we first describe a computer architecture called MICADO designed for French nuclear industry. We then present outgoing projects on our industry. A special point is made on power electronics for remote-operated and legged robots. (authors). 7 refs., 2 figs

  12. Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses

    Science.gov (United States)

    Abramovitz, A.

    2011-01-01

    This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as "Power…

  13. An improved electron impact ion source power supply

    International Nuclear Information System (INIS)

    Beaver, E.M.

    1974-01-01

    An electron impact ion source power supply has been developed that offers improved ion beam stability. The electrical adjustments of ion source parameters are more flexible, and safety features are incorporated to protect the electron emitting filament from accidental destruction. (author)

  14. Fault tolerant embedded computers and power electronics for nuclear robotics

    Energy Technology Data Exchange (ETDEWEB)

    Giraud, A.; Robiolle, M.

    1995-12-31

    For requirements of nuclear industries, it is necessary to use embedded rad-tolerant electronics and high-level safety. In this paper, we first describe a computer architecture called MICADO designed for French nuclear industry. We then present outgoing projects on our industry. A special point is made on power electronics for remote-operated and legged robots. (authors). 7 refs., 2 figs.

  15. Power Electronics as key technology in wind turbines

    DEFF Research Database (Denmark)

    Blaabjerg, Frede

    2005-01-01

    This paper discuss the development in wind turbines in a two-decade perspective looking at the technology based on track records. Different power electronic topologies for interfacing the wind turbine to the grid are discussed and related to the possibility for the wind turbine to act as a power...

  16. Power Electronics for the Next Generation Wind Turbine System

    DEFF Research Database (Denmark)

    Ma, Ke

    This book presents recent studies on the power electronics used for the next generation wind turbine system. Some criteria and tools for evaluating and improving the critical performances of the wind power converters have been proposed and established. The book addresses some emerging problems...

  17. FEL radiation power available in electron storage rings

    International Nuclear Information System (INIS)

    Miyahara, Yoshikazu

    1994-01-01

    FEL radiation power available in electron storage rings was studied in the small signal regime in considering the increase of the energy spread of the electron beam caused by the FEL interaction and the decrease of the FEL gain with the increase of the energy spread in addition to the radiation damping and the quantum excitation. All these effects were considered separately, and combined with FEL power equations. The radiation power available was expressed explicitly with the parameters of the storage ring, the wiggler and the mirrors. The transient process of FEL lasing is simulated with the power equations. A rough estimation is made of the radiation power available by the FEL at different beam energies, and optimization of FEL parameters for a higher radiation power is discussed. ((orig.))

  18. Stop Ticks

    Science.gov (United States)

    ... PDF file Microsoft PowerPoint file Microsoft Word file Microsoft ... Center for Emerging and Zoonotic Infectious Diseases Page maintained by: Office of the Associate Director for Communication, Digital Media ...

  19. Very High Frequency Switch-Mode Power Supplies.:Miniaturization of Power Electronics.

    OpenAIRE

    Madsen, Mickey Pierre; Andersen, Michael A. E.; Knott, Arnold

    2015-01-01

    The importance of technology and electronics in our daily life is constantly increasing. At the same time portability and energy efficiency are currently some of the hottest topics. This creates a huge need for power converters in a compact form factor and with high efficiency, which can supply these electronic devices. This calls for new technologies in order to miniaturize the power electronics of today. One way to do this is by increasing the switching frequency dramatically and develop ve...

  20. High-gradient electron accelerator powered by a relativisitic klystron

    International Nuclear Information System (INIS)

    Allen, M.A.; Boyd, J.K.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Haimson, J.; Hoag, H.A.; Hopkins, D.B.; Houck, T.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Mecklenburg, B.; Miller, R.H.; Ruth, R.D.; Ryne, R.D.; Sessler, A.M.; Vlieks, A.E.; Wang, J.W.; Westenskow, G.A.; Yu, S.S.

    1989-01-01

    We have used relativistic klystron technology to extract 290 MW of peak power at 11.4 GHz from an induction linac beam, and to power a short 11.4-GHz high-gradient accelerator. We have measured rf phase stability, field emission, and the momentum spectrum of an accelerated electron beam. An average accelerating gradient of 84 MV/m has been achieved with 80 MW of relativistic klystron power

  1. Using mathematical software to design power electronic converters

    Science.gov (United States)

    Hinov, Nikolay; Hranov, Tsveti

    2017-12-01

    In the paper is presented mathematical software, which was used for design of power electronic devices. Examined to different example, which are applied to designing electronic converters. In this way, it is possible to play different combinations of the circuit elements by simple means, thus optimizing according to certain criteria and limitations. Free software with a simple and intuitive interface is selected. No special user training is required to work with it and no further training is required. The use of mathematical software greatly facilitates the design, assists and makes it attractive and accessible to a wider range of students and specialists in power electronics training.

  2. The Energy Processing by Power Electronics and its Impact on Power Quality

    OpenAIRE

    J.E. Rocha; W.D.C Sanchez

    2012-01-01

    This paper discusses the electrical architectures adopted in wind turbines and its impact on the harmonic flux at the connected electric network. The integration of wind electric generators with the power grid needs energy processing by power electronics. It shows that different types of wind turbine generator systems use different types of electronic converters. This work provides a discussion on harmonic distortion taking place on the generator side, as well as in the power grid side. Key...

  3. Power electronics applied to industrial systems and transports

    CERN Document Server

    Patin, Nicolas

    2015-01-01

    This book provides a comprehensive overview of power electronic converters (DC / DC, DC / AC, AC / DC and AC / AC) conventionally used in industrial and transportation applications, specifically for the supply of electric machines with variable speed drop off window. From the perspective of design and sizing, this book presents the different functions encountered in a modular way for power electronics.Power Converters and Their Control details less traditional topics such as matrix converters and multilevel converters. This book also features a case study design of an industrial controller, wh

  4. Digital signal processing in power electronics control circuits

    CERN Document Server

    Sozanski, Krzysztof

    2013-01-01

    Many digital control circuits in current literature are described using analog transmittance. This may not always be acceptable, especially if the sampling frequency and power transistor switching frequencies are close to the band of interest. Therefore, a digital circuit is considered as a digital controller rather than an analog circuit. This helps to avoid errors and instability in high frequency components. Digital Signal Processing in Power Electronics Control Circuits covers problems concerning the design and realization of digital control algorithms for power electronics circuits using

  5. High power microwave emission and diagnostics of microsecond electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Gilgenbach, R; Hochman, J M; Jayness, R; Rintamaki, J I; Lau, Y Y; Luginsland, J; Lash, J S [Univ. of Michigan, Ann Arbor, MI (United States). Intense Electron Beam Interaction Lab.; Spencer, T A [Air Force Phillips Lab., Kirtland AFB, NM (United States)

    1997-12-31

    Experiments were performed to generate high power, long-pulse microwaves by the gyrotron mechanism in rectangular cross-section interaction cavities. Long-pulse electron beams are generated by MELBA (Michigan Electron Long Beam Accelerator), which operates with parameters: -0.8 MV, 1-10 kA, and 0.5-1 microsecond pulse length. Microwave power levels are in the megawatt range. Polarization control is being studied by adjustment of the solenoidal magnetic field. Initial results show polarization power ratios up to a factor of 15. Electron beam dynamics (V{sub perp}/V{sub par}) are being measured by radiation darkening on glass plates. Computer modeling utilizes the MAGIC Code for electromagnetic waves and a single electron orbit code that includes a distribution of angles. (author). 4 figs., 4 refs.

  6. On grid-connected power electronic systems: power quality improvement application

    International Nuclear Information System (INIS)

    Etxeberria-Otadui, I.

    2003-09-01

    The present PhD thesis deals with distribution grid-connected power electronic devices. The main focus has been power quality improvement with power electronic devices. The theoretical aspects and the power quality improvement techniques are presented and discussed. Power electronic devices are then presented, modelled and controlled. Original disturbance identification, power management and current/voltage control methods have been proposed, tested and analysed. A flexible test-bench, composed of a series and a shunt compensator, has been designed and built in order to test the studied control algorithms. These tests have permitted to experimentally evaluate and validate the proposed control algorithms and to make evident several problems that are not always visible on the theory. The conclusions outline the main short and mid term objectives and challenges in the field of power quality improvement devices. (author)

  7. Power electronics for renewable energy systems, transportation and industrial applications

    CERN Document Server

    Malinowski, Mariusz; Al-Haddad, Kamal

    2014-01-01

    Power Electronics for Renewable Energy, Transportation, and Industrial Applications combines state-of-the-art global expertise to present the latest research on power electronics and its application in transportation, renewable energy, and different industrial applications. This timely book aims to facilitate the implementation of cutting-edge techniques to design problems offering innovative solutions to the growing power demands in small- and large-size industries. Application areas in the book range from smart homes and electric and plug-in hybrid electrical vehicles (PHEVs), to smart distribution and intelligence operation centers where significant energy efficiency improvements can be achieved through the appropriate use and design of power electronics and energy storage devices.

  8. Advanced power electronics and electric machinery program

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2007-12-01

    The U.S. Department of Energy (DOE) and the U.S. Council for Automotive Research (composed of automakers Ford, General Motors, and Chrysler) announced in January 2002 a new cooperative research effort. Known as "FreedomCAR" (derived from "Freedom" and "Cooperative Automotive Research"), it represents DOE's commitment to developing public/private partnerships to fund high-risk, high-payoff research into advanced automotive technologies. Efficient fuel cell technology, which uses hydrogen to power automobiles without air pollution, is a very promising pathway to achieving the ultimate vision. The new partnership replaces and builds upon the Partnership for a New Generation of Vehicles initiative that ran from 1993 through 2001.

  9. Integrated Silicon Carbide Power Electronic Block

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, Rahul [Global Power Technologies Group, Inc., Lake Forest, CA (United States)

    2017-11-07

    Research involved in this project is aimed at monolithically integrating an anti-parallel diode to the SiC MOSFET switch, so as to avoid having to use an external anti-parallel diode in power circuit applications. SiC MOSFETs are replacing Si MOSFETs and IGBTs in many applications, yet the high bandgap of the body diode in SiC MOSFET and consequent need for an external anti-parallel diode increases costs and discourages circuit designers from adopting this technology. Successful demonstration and subsequent commercialization of this technology would reduce SiC MOSFET cost and additionally reduce component count as well as other costs at the power circuit level. In this Phase I project, we have created multiple device designs, set up a process for device fabrication at the 150mm SiC foundry XFAB Texas, demonstrated unit-processes for device fabrication in short loops and started full flow device fabrication. Key findings of the development activity were: The limits of coverage of photoresist over the topology of thick polysilicon structures covered with oxide, which required larger feature dimensions to overcome; and The insufficient process margin for removing oxide spacers from polysilicon field ring features which could result in loss of some features without further process development No fundamental obstacles were uncovered during the process development. Given sufficient time for additional development it is likely that processes could be tuned to realize the monolithically integrated SiC JBS diode and MOSFET. Sufficient funds were not available in this program to resolve processing difficulties and fabricate the devices.

  10. A high average power beam dump for an electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xianghong, E-mail: xl66@cornell.edu [Cornell Laboratory of Accelerator-based Sciences and Education, Cornell University, Ithaca, NY 14853 (United States); Bazarov, Ivan; Dunham, Bruce M.; Kostroun, Vaclav O.; Li, Yulin; Smolenski, Karl W. [Cornell Laboratory of Accelerator-based Sciences and Education, Cornell University, Ithaca, NY 14853 (United States)

    2013-05-01

    The electron beam dump for Cornell University's Energy Recovery Linac (ERL) prototype injector was designed and manufactured to absorb 600 kW of electron beam power at beam energies between 5 and 15 MeV. It is constructed from an aluminum alloy using a cylindrical/conical geometry, with water cooling channels between an inner vacuum chamber and an outer jacket. The electron beam is defocused and its centroid is rastered around the axis of the dump to dilute the power density. A flexible joint connects the inner body and the outer jacket to minimize thermal stress. A quadrant detector at the entrance to the dump monitors the electron beam position and rastering. Electron scattering calculations, thermal and thermomechanical stress analysis, and radiation calculations are presented.

  11. High-power fiber lasers for photocathode electron injectors

    Directory of Open Access Journals (Sweden)

    Zhi Zhao

    2014-05-01

    Full Text Available Many new applications for electron accelerators require high-brightness, high-average power beams, and most rely on photocathode-based electron injectors as a source of electrons. To achieve such a photoinjector, one requires both a high-power laser system to produce the high average current beam, and also a system at reduced repetition rate for electron beam diagnostics to verify high beam brightness. Here we report on two fiber laser systems designed to meet these specific needs, at 50 MHz and 1.3 GHz repetition rate, together with pulse pickers, second harmonic generation, spatiotemporal beam shaping, intensity feedback, and laser beam transport. The performance and flexibility of these laser systems have allowed us to demonstrate electron beam with both low emittance and high average current for the Cornell energy recovery linac.

  12. Power electronics - key technology for renewable energy systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Iov, Florin; Kerekes, Tamas

    2011-01-01

    sources to renewable energy sources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss trends of the most emerging renewable energy sources, wind energy and photovoltaics, which by means of power electronics...... as efficient as possible. Further, the emerging climate changes is arguing to find sustainable future solutions. Of many options, two major technologies will play important roles to solve parts of those future problems. One is to change the electrical power production from conventional, fossil based energy......The electrical energy consumption continues to grow and more applications are based on electricity. We can expect that more 60% of all energy consumption will be converted and used as electricity. Therefore, it is a demand that production, distribution and use of electrical energy are done...

  13. The powerful pulsed electron beam effect on the metallic surfaces

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Yuferov, V.B.; Kosik, N.A.; Druj, O.S.; Skibenko, E.I.

    2001-01-01

    Experimental results of the influence of powerful pulsed electron beams on the surface structure,hardness and corrosion resistance of the Cr18ni10ti steel are presented. The experiments were carried out in the powerful electron accelerators of directional effect VGIK-1 and DIN-2K with an energy up to approx 300 KeV and a power density of 10 9 - 10 11 W/cm 2 for micro- and nanosecond range. The essential influence of the irradiation power density on the material structure was established. Pulsed powerful beam action on metallic surface leads to surface melting,modification of the structure and structure-dependent material properties. The gas emission and mass-spectrometer analysis of the beam-surface interaction were defined

  14. Power Electronics and Control of Renewable Energy Systems

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Sera, Dezso

    2007-01-01

    sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss some of the most emerging renewable energy sources......The global electrical energy consumption is still rising and there is a demand to double the power capacity within 20 years. The production, distribution and use of energy should be as technological efficient as possible and incentives to save energy at the end-user should also be set up....... Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production...

  15. Remote Shutoff Stops Runaway Lawnmower

    Science.gov (United States)

    Grambo, Alan A.

    2007-01-01

    In this article, the author describes how electronics students at Central Nine Career Center designed a kill switch circuit to stop a runaway lawnmower. This project is ideal for a career center since the electronics/robotics, small engines and horticulture classes can all work together on their respective parts of the modification, installation…

  16. A high power, tunable free electron maser for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Urbanus, W.H.; Bratman, V.L.; Bongers, W.A.; Caplan, M.; Denisov, G.G.; Geer, C.A.J. van der; Manintveld, P.; Militsyn, B.; Oomens, A.A.M.; Poelman, A.J.; Plomp, J.; Pluygers, J.; Savilov, A.V.; Smeets, P.H.M.; Sterk, A.B.; Verhoeven, A.G.A

    2001-01-01

    The Fusion-FEM experiment, a high-power, electrostatic free-electron maser being built at the FOM-Institute for Plasma Physics 'Rijnhuizen', is operated at various frequencies. So far, experiments were done without a depressed collector, and the pulse length was limited to 12 {mu}s. Nevertheless, many aspects of generation of mm-wave power have been explored, such as the dependency on the electron beam energy and beam current, and cavity settings such as the feedback coefficient. An output power of 730 kW at 206 GHz is generated with a 7.2 A, 1.77 MeV electron beam, and 360 kW at 167 GHz is generated with a 7.4 A, 1.61 MeV electron beam. It is shown experimentally and by simulations that, depending on the electron beam energy, the FEM can operate in single-frequency regime. The next step of the FEM experiment is to reach a pulse length of 100 ms. The major part of the beam line, the high voltage systems, and the collector have been completed. The undulator and mm-wave cavity are now at high voltage (2 MV). The new mm-wave transmission line, which transports the mm-wave output power from the high-voltage terminal to ground and outside the pressure tank, has been tested at low power.

  17. Bus Participation Factor Analysis for Harmonic Instability in Power Electronics Based Power Systems

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2018-01-01

    Compared with the conventional power systems, large-scale power electronics based power systems present a more complex situation, where harmonic instability may be induced by the mutual interactions between the inner control loops of the converters. This paper presents an approach to locate which...... power converters and buses are more sensitive and have significant contribution to the harmonic instability. In the approach, a power electronics based system is introduced as a Multi-Input Multi-Output (MIMO) dynamic system by means of a dynamic admittance matrix. Bus Participation Factors (PFs......) are calculated by the oscillatory mode sensitivity analysis versus the elements of the MIMO transfer function matrix. The PF analysis detects which power electronic converters or buses have a higher participation in harmonic instability excitation than others or at which buses such instability problems have...

  18. Modeling and analysis of harmonic resonance in a power electronics based AC power system

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2013-01-01

    The dynamic interactions among the interconnected power converters may bring in harmonic resonance in a power electronics based power system. This paper addresses this issue in a power system dominated by multiple current- and voltage-controlled inverters with LCL- and LC-filters. The impedance...... stability criterion. To validate the theoretical analysis, the time domain simulations and experimental tests on a three-inverter-based system are presented....

  19. Design of 120 MW beam power electron gun for high power klystron

    International Nuclear Information System (INIS)

    Zhou Zusheng; Dong Dong

    2005-01-01

    An electron gun was designed and the beam optics for a China-made 50 MW klystron was simulated. The electron gun ceramic cylinder was designed and optimized. The China-made cathode was replaced with an imported one to lessen evaporation and arcing. The high voltage (320 kV) of the cathode was increased to meet the klystron output power demand and a low electric field strength (22.1 kV/mm) electron gun was designed to avoid the high power operation which damaged the ceramic cylinder. The klystron output power was increased and life span extended. (authors)

  20. Inner-shell corrections to the Bethe stopping-power formula evaluated from a realistic atomic model

    International Nuclear Information System (INIS)

    Inokuti, M.; Manson, S.T.

    1985-01-01

    Generalized oscillator strengths for K- and L-shell ionization have been calculated using a central potential derived from the Hartree-Slater model. In cases in which an ejected electron carries low kinetic energies, sizable differences with hydrogenic-model calculations are evident

  1. SU-E-J-136: Investigation Into Robustness of Stopping Power Calculated by DECT and SECT for Proton Therapy Treatment Planning

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J [University of Adelaide, Adelaide, SA (Australia); Penfold, S [University of Adelaide, Adelaide, SA (Australia); Royal Adelaide Hospital, Adelaide, SA (Australia)

    2015-06-15

    Purpose: To investigate the robustness of dual energy CT (DECT) and single energy CT (SECT) proton stopping power calibration techniques and quantify the associated errors when imaging a phantom differing in chemical composition to that used during stopping power calibration. Methods: The CIRS tissue substitute phantom was scanned in a CT-simulator at 90kV and 140kV. This image set was used to generate a DECT proton SPR calibration based on a relationship between effective atomic number and mean excitation energy. A SECT proton SPR calibration based only on Hounsfield units (HUs) was also generated. DECT and SECT scans of a second phantom of known density and chemical composition were performed. The SPR of the second phantom was calculated with the DECT approach (SPR-DECT),the SECT approach (SPR-SECT) and finally the known density and chemical composition of the phantom (SPR-ref). The DECT and SECT image sets were imported into the Pinnacle{sup 3} research release of proton therapy treatment planning. The difference in dose when exposed to a common pencil beam distribution was investigated. Results: SPR-DECT was found to be in better agreement with SPR-ref than SPR- SECT. The mean difference in SPR for all materials was 0.51% for DECT and 6.89% for SECT. With the exception of Teflon, SPR-DECT was found to agree with SPR-ref to within 1%. Significant differences in calculated dose were found when using the DECT image set or the SECT image set. Conclusion: The DECT calibration technique was found to be more robust to situations in which the physical properties of the test materials differed from the materials used during SPR calibration. Furthermore, it was demonstrated that the DECT and SECT SPR calibration techniques can Result in significantly different calculated dose distributions.

  2. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    International Nuclear Information System (INIS)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H

    2016-01-01

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  3. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  4. Multi-time scale dynamics in power electronics-dominated power systems

    Science.gov (United States)

    Yuan, Xiaoming; Hu, Jiabing; Cheng, Shijie

    2017-09-01

    Electric power infrastructure has recently undergone a comprehensive transformation from electromagnetics to semiconductors. Such a development is attributed to the rapid growth of power electronic converter applications in the load side to realize energy conservation and on the supply side for renewable generations and power transmissions using high voltage direct current transmission. This transformation has altered the fundamental mechanism of power system dynamics, which demands the establishment of a new theory for power system control and protection. This paper presents thoughts on a theoretical framework for the coming semiconducting power systems.

  5. Power Electronics Thermal Management R&D (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S.

    2014-11-01

    This project will investigate and develop thermal-management strategies for wide bandgap (WBG)-based power electronics systems. Research will be carried out to deal with thermal aspects at the module- and system-level. Module-level research will focus on die- and substrate-integrated cooling strategies and heat-transfer enhancement technologies. System-level research will focus on thermal-management strategies for the entire power electronics system to enable smart packaging solutions. One challenge with WBG device-based power electronics is that although losses in the form of heat may be lower, the footprint of the components is also likely to be reduced to reduce cost, weight, and volume. Combined with higher operational temperatures, this creates higher heat fluxes which much be removed from a smaller footprint, requiring advanced cooling strategies.

  6. High power electron accelerators for flue gas treatment

    International Nuclear Information System (INIS)

    Zimek, Z.

    2011-01-01

    Flue gas treatment process based on electron beam application for SO 2 and NO x removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

  7. Modeling power electronics and interfacing energy conversion systems

    CERN Document Server

    Simões, Marcelo Godoy

    2017-01-01

    Discusses the application of mathematical and engineering tools for modeling, simulation and control oriented for energy systems, power electronics and renewable energy. This book builds on the background knowledge of electrical circuits, control of dc/dc converters and inverters, energy conversion and power electronics. The book shows readers how to apply computational methods for multi-domain simulation of energy systems and power electronics engineering problems. Each chapter has a brief introduction on the theoretical background, a description of the problems to be solved, and objectives to be achieved. Block diagrams, electrical circuits, mathematical analysis or computer code are covered. Each chapter concludes with discussions on what should be learned, suggestions for further studies and even some experimental work.

  8. High power electron accelerators for flue gas treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zimek, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2011-07-01

    Flue gas treatment process based on electron beam application for SO{sub 2} and NO{sub x} removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

  9. Site selection of active damper for stabilizing power electronics based power distribution system

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    electronics based power device, which provides an adjustable damping capability to the power system where the voltage harmonic instability is measured. It can stabilize by adjusting the equivalent node impedance with its plug and play feature. This feature gives many degrees of freedom of its installation......Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a power...... point when the system has many nodes. Therefore, this paper addresses the proper placement of an active damper in an unstable small-scale power distribution system. A time-domain model of the Cigre benchmark low-vltage network is used as a test field. The result shows the active damper location...

  10. DANBIO-powerful research database and electronic patient record

    DEFF Research Database (Denmark)

    Hetland, Merete Lund

    2011-01-01

    an overview of the research outcome and presents the cohorts of RA patients. The registry, which is approved as a national quality registry, includes patients with RA, PsA and AS, who are followed longitudinally. Data are captured electronically from the source (patients and health personnel). The IT platform...... as an electronic patient 'chronicle' in routine care, and at the same time provides a powerful research database....

  11. Power electronics - The key technology for Renewable Energy Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke; Yang, Yongheng

    2014-01-01

    The energy paradigms in many countries (e.g. Germany and Denmark) have experienced a significant change from fossil-based resources to clean renewables (e.g. wind turbines and photovoltaics) in the past few decades. The scenario of highly penetrated renewables is going to be further enhanced...... - Denmark expects to be 100 % fossil-free by 2050. Consequently, it is required that the production, distribution and use of the energy should be as technologically efficient as possible and incentives to save energy at the end-user should also be strengthened. In order to realize the transition smoothly...... and effectively, energy conversion systems, currently based on power electronics technology, will again play an essential role in this energy paradigm shift. Using highly efficient power electronics in power generation, power transmission/distribution and end-user application, together with advanced control...

  12. Electric vehicle recycling 2020: Key component power electronics.

    Science.gov (United States)

    Bulach, Winfried; Schüler, Doris; Sellin, Guido; Elwert, Tobias; Schmid, Dieter; Goldmann, Daniel; Buchert, Matthias; Kammer, Ulrich

    2018-04-01

    Electromobility will play a key role in order to reach the specified ambitious greenhouse gas reduction targets in the German transport sector of 42% between 1990 and 2030. Subsequently, a significant rise in the sale of electric vehicles (EVs) is to be anticipated in future. The amount of EVs to be recycled will rise correspondingly after a delay. This includes the recyclable power electronics modules which are incorporated in every EV as an important component for energy management. Current recycling methods using car shredders and subsequent post shredder technologies show high recycling rates for the bulk metals but are still associated with high losses of precious and strategic metals such as gold, silver, platinum, palladium and tantalum. For this reason, the project 'Electric vehicle recycling 2020 - key component power electronics' developed an optimised recycling route for recycling power electronics modules from EVs which is also practicable in series production and can be implemented using standardised technology. This 'WEEE recycling route' involves the disassembly of the power electronics from the vehicle and a subsequent recycling in an electronic end-of-life equipment recycling plant. The developed recycling process is economical under the current conditions and raw material prices, even though it involves considerably higher costs than recycling using the car shredder. The life cycle assessment shows basically good results, both for the traditional car shredder route and the developed WEEE recycling route: the latter provides additional benefits from some higher recovery rates and corresponding credits.

  13. Power electronics applied to industrial systems and transports

    CERN Document Server

    Patin, Nicolas

    2015-01-01

    Power electronics is based on the switching operating mode of semiconductor components. On this basis, the concepts of type (voltage or current) and reversibility of interconnected sources make it possible to apply a methodology for the synthesis of various types of converters. This book also focuses on the importance of packaging by reviewing the electrical representation of components’ thermal models and the currently available electronics’ cooling technologies. Modeling is discussed, as well as different technological aspects used in the engineering design of an electronic power converter, useful for obtaining satisfactory performance and reliability.

  14. VISA Final Report: Fully Integrated Power Electronic Systems in Automotive Electronics

    NARCIS (Netherlands)

    Waffenschmidt, E.

    2011-01-01

    This report summarizes the activities related to the public funded project “Vollintegrierte leistungselektronische Systeme in der Automobilelektronik – VISA” (Fully Integrated Power Electronic Systems in Automotive Electronics). Aim of the project is to investigate the integration of components into

  15. Junction Temperature Control for More Reliable Power Electronics

    DEFF Research Database (Denmark)

    Andresen, Markus; Ma, Ke; Buticchi, Giampaolo

    2018-01-01

    The thermal stress of power electronic components is one of the most important causes of their failure. Proper thermal management plays an important role for more reliable and cost-effective energy conversion. As one of the most vulnerable and expensive components, power semiconductor components ...... the desired cost-benefit tradeoff. This paper analyzes also the many open questions of this research area. Among them, it is worth highlighting that a verification of the actual lifetime extension is still missing....

  16. Modern power electronics in the Transrapid 06 II maglev train

    Energy Technology Data Exchange (ETDEWEB)

    Ruoss, W

    1987-04-01

    The Transrapid 06 II magler train comprises a number of power electronics components, e.g. modern, fast-switching power transistors of 100 kHz and with breaking capacities up to 100 kVA. The modular component design on the basis of established transistorized mountings and switching circuit components is described, as are the measures taken to assure high reliability and availability.

  17. Phase synchronized quasiperiodicity in power electronic inverter systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Andriyanov, Alexey I.

    2014-01-01

    The development of switch-mode operated power electronic converter systems has provided a broad range of new effective approaches to the conversion of electric power. In this paper we describe the transitions from regular periodic operation to quasiperiodicity and high-periodic resonance behavior...... findings are verified through comparison with an experimental inverter system. The results shed light on the transitions to quasiperiodicity and to various forms of three-frequency dynamics in non-smooth systems....

  18. Power electronic converters modeling and control with case studies

    CERN Document Server

    Bacha, Seddik; Bratcu, Antoneta Iuliana

    2014-01-01

    Modern power electronic converters are involved in a very broad spectrum of applications: switched-mode power supplies, electrical-machine-motion-control, active power filters, distributed power generation, flexible AC transmission systems, renewable energy conversion systems and vehicular technology, among them. Power Electronics Converters Modeling and Control teaches the reader how to analyze and model the behavior of converters and so to improve their design and control. Dealing with a set of confirmed algorithms specifically developed for use with power converters, this text is in two parts: models and control methods. The first is a detailed exposition of the most usual power converter models: ·        switched and averaged models; ·        small/large-signal models; and ·        time/frequency models. The second focuses on three groups of control methods: ·        linear control approaches normally associated with power converters; ·        resonant controllers b...

  19. Development of a one-stop beam verification system using electronic portal imaging devices for routine quality assurance

    International Nuclear Information System (INIS)

    Lim, Sangwook; Ma, Sun Young; Jeung, Tae Sig; Yi, Byong Yong; Lee, Sang Hoon; Lee, Suk; Cho, Sam Ju; Choi, Jinho

    2012-01-01

    In this study, a computer-based system for routine quality assurance (QA) of a linear accelerator (linac) was developed by using the dosimetric properties of an amorphous silicon electronic portal imaging device (EPID). An acrylic template phantom was designed such that it could be placed on the EPID and be aligned with the light field of the collimator. After irradiation, portal images obtained from the EPID were transferred in DICOM format to a computer and analyzed using a program we developed. The symmetry, flatness, field size, and congruence of the light and radiation fields of the photon beams from the linac were verified simultaneously. To validate the QA system, the ion chamber and film (X-Omat V2; Kodak, New York, NY) measurements were compared with the EPID measurements obtained in this study. The EPID measurements agreed with the film measurements. Parameters for beams with energies of 6 MV and 15 MV were obtained daily for 1 month using this system. It was found that our QA tool using EPID could substitute for the film test, which is a time-consuming method for routine QA assessment.

  20. Development of a one-stop beam verification system using electronic portal imaging devices for routine quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sangwook, E-mail: medicalphysics@hotmail.com [Department of Radiation Oncology, Kosin University College of Medicine, Seo-gu, Busan (Korea, Republic of); Ma, Sun Young; Jeung, Tae Sig [Department of Radiation Oncology, Kosin University College of Medicine, Seo-gu, Busan (Korea, Republic of); Yi, Byong Yong [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States); Lee, Sang Hoon [Department of Radiation Oncology, Cheil General Hospital and Women' s Healthcare Center, Kwandong University College of Medicine, Jung-gu, Seoul (Korea, Republic of); Lee, Suk [Department of Radiation Oncology, College of Medicine, Korea University, Seongbuk-gu, Seoul (Korea, Republic of); Cho, Sam Ju [Department of Radiation Oncology, Eulji University School of Medicine, Eulji General Hospital, Nowon-gu, Seoul (Korea, Republic of); Choi, Jinho [Department of Radiation Oncology, Gachon University of Medicine and Science, Namdong-gu, Incheon (Korea, Republic of)

    2012-10-01

    In this study, a computer-based system for routine quality assurance (QA) of a linear accelerator (linac) was developed by using the dosimetric properties of an amorphous silicon electronic portal imaging device (EPID). An acrylic template phantom was designed such that it could be placed on the EPID and be aligned with the light field of the collimator. After irradiation, portal images obtained from the EPID were transferred in DICOM format to a computer and analyzed using a program we developed. The symmetry, flatness, field size, and congruence of the light and radiation fields of the photon beams from the linac were verified simultaneously. To validate the QA system, the ion chamber and film (X-Omat V2; Kodak, New York, NY) measurements were compared with the EPID measurements obtained in this study. The EPID measurements agreed with the film measurements. Parameters for beams with energies of 6 MV and 15 MV were obtained daily for 1 month using this system. It was found that our QA tool using EPID could substitute for the film test, which is a time-consuming method for routine QA assessment.

  1. High-voltage pulse generator for electron gun power supply

    International Nuclear Information System (INIS)

    Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.

    1987-01-01

    High-voltage pulse generator with combined capacitive and inductive energy storages for electron gun power supply is described. Hydrogen thyratron set in a short magnetic lense is a current breaker. Times of current interruption in thyratrons are in the range from 100 to 300 ns. With 1 kV charging voltage of capacitive energy storage 25 kV voltage pulse is obtained in the load. The given high-voltage pulse generator was used for supply of an electron gun generating 10-30 keV low-energy electron beam

  2. Development of a high power free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Min; Lee, Byung Chul; Kim, Sun Kook; Jung, Yung Wook; Cho, Sung Oh [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-01-01

    A millimeter-wave free electron laser (FEL) driven by a recirculating electrostatic accelerator has been developed. The wavelength of the FEL is tunable in the range of 3 - 12 mm by tuning the energy of the electron beam. The output power is estimated to be 1 kW. The electrostatic accelerator is composed of high-current electron gun, acceleration tube, high-voltage generator, high-voltage terminal, deceleration tube, electron collator, and vacuum pumps. Two types of LaB{sub 6}-based thermionic electron guns (triode gun and diode gun) and their power supplies have been developed. The voltage of the guns is 30 kV and the output current is - 2 A. A beam-focusing planar undulator and a permanent-magnet helical undulator have been developed and 3D trajectories of electron beam in the undulators have been calculated to find optimal input condition of electron beam. 135 figs, 15 pix, 17 tabs, 98 refs. (Author).

  3. Development of a high power free-electron laser

    International Nuclear Information System (INIS)

    Lee, Jong Min; Lee, Byung Chul; Kim, Sun Kook; Jung, Yung Wook; Cho, Sung Oh

    1995-01-01

    A millimeter-wave free electron laser (FEL) driven by a recirculating electrostatic accelerator has been developed. The wavelength of the FEL is tunable in the range of 3 - 12 mm by tuning the energy of the electron beam. The output power is estimated to be 1 kW. The electrostatic accelerator is composed of high-current electron gun, acceleration tube, high-voltage generator, high-voltage terminal, deceleration tube, electron collator, and vacuum pumps. Two types of LaB 6 -based thermionic electron guns (triode gun and diode gun) and their power supplies have been developed. The voltage of the guns is 30 kV and the output current is - 2 A. A beam-focusing planar undulator and a permanent-magnet helical undulator have been developed and 3D trajectories of electron beam in the undulators have been calculated to find optimal input condition of electron beam. 135 figs, 15 pix, 17 tabs, 98 refs. (Author)

  4. High performance protection circuit for power electronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Tudoran, Cristian D., E-mail: cristian.tudoran@itim-cj.ro; Dădârlat, Dorin N.; Toşa, Nicoleta; Mişan, Ioan [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, PO 5 Box 700, 400293 Cluj-Napoca (Romania)

    2015-12-23

    In this paper we present a high performance protection circuit designed for the power electronics applications where the load currents can increase rapidly and exceed the maximum allowed values, like in the case of high frequency induction heating inverters or high frequency plasma generators. The protection circuit is based on a microcontroller and can be adapted for use on single-phase or three-phase power systems. Its versatility comes from the fact that the circuit can communicate with the protected system, having the role of a “sensor” or it can interrupt the power supply for protection, in this case functioning as an external, independent protection circuit.

  5. Conceptual design and simulation investigation of an electronic cooling device powered by hot electrons

    International Nuclear Information System (INIS)

    Su, Guozhen; Zhang, Yanchao; Cai, Ling; Su, Shanhe; Chen, Jincan

    2015-01-01

    Most electronic cooling devices are powered by an external bias applied between the cold and the hot reservoirs. Here we propose a new concept of electronic cooling, in which cooling is achieved by using a reservoir of hot electrons as the power source. The cooling device incorporates two energy filters with the Lorentzian transmission function to respectively select low- and high-energy electrons for transport. Based on the proposed model, we analyze the performances of the device varying with the resonant levels and half widths of two energy filters and establish the optimal configuration of the cooling device. It is believed that such a novel device may be practically used in some nano-energy fields. - Highlights: • A new electronic cooling device powered by hot electrons is proposed. • Two energy filters are employed to select the electrons for transport. • The effects of the resonant levels and half widths of two filters are discussed. • The maximum cooling power and coefficient of performance are calculated. • The optimal configuration of the cooling device is determined.

  6. Power Block Geometry Applied to the Building of Power Electronics Converters

    Science.gov (United States)

    dos Santos, E. C., Jr.; da Silva, E. R. C.

    2013-01-01

    This paper proposes a new methodology, Power Block Geometry (PBG), for the presentation of power electronics topologies that process ac voltage. PBG's strategy uses formal methods based on a geometrical representation with particular rules and defines a universe with axioms and conjectures to establish a formation law. It allows power…

  7. FY2009 Annual Progress Report for Advanced Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Susan A. [Dept. of Energy (DOE), Washington DC (United States)

    2010-01-01

    The Advanced Power Electronics and Electric Machines (APEEM) subprogram within the Vehicle Technologies Program provides support and guidance for many cutting-edge automotive technologies now under development. Research is focused on understanding and improving the way the various new components of tomorrow's automobiles will function as a unified system to improve fuel efficiency.

  8. Simulation Tools for Power Electronics Courses Based on Java Technologies

    Science.gov (United States)

    Canesin, Carlos A.; Goncalves, Flavio A. S.; Sampaio, Leonardo P.

    2010-01-01

    This paper presents interactive power electronics educational tools. These interactive tools make use of the benefits of Java language to provide a dynamic and interactive approach to simulating steady-state ideal rectifiers (uncontrolled and controlled; single-phase and three-phase). Additionally, this paper discusses the development and use of…

  9. Editorial for the IEEE Transactions on Power Electronics, January 2009

    DEFF Research Database (Denmark)

    Blaabjerg, Frede

    2009-01-01

    I am entering the fourth year as the Editor in Chief of the IEEE TRANSACTIONS ON POWER ELECTRONICS. A position like this becomes more and more important for the technical field as publishing in a peer-reviewed highly ranked journal has influence on the industrial and academic career. It is a way...

  10. Body of Knowledge for Silicon Carbide Power Electronics

    Science.gov (United States)

    Boomer, Kristen; Lauenstein, Jean-Marie; Hammoud, Ahmad

    2016-01-01

    Wide band gap semiconductors, such as silicon carbide (SiC), have emerged as very promising materials for future electronic components due to the tremendous advantages they offer in terms of power capability, extreme temperature tolerance, and high frequency operation. This report documents some issues pertaining to SiC technology and its application in the area of power electronics, in particular those geared for space missions. It also serves as a body of knowledge (BOK) in reference to the development and status of this technology obtained via literature and industry survey as well as providing a listing of the major manufacturers and their capabilities. Finally, issues relevant to the reliability of SiC-based electronic parts are addressed and limitations affecting the full utilization of this technology are identified.

  11. Power Electronics Thermal Management R&D: Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilbert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-04-08

    The objective for this project is to develop thermal management strategies to enable efficient and high-temperature wide-bandgap (WBG)-based power electronic systems (e.g., emerging inverter and DC-DC converter). Device- and system-level thermal analyses are conducted to determine the thermal limitations of current automotive power modules under elevated device temperature conditions. Additionally, novel cooling concepts and material selection will be evaluated to enable high-temperature silicon and WBG devices in power electronics components. WBG devices (silicon carbide [SiC], gallium nitride [GaN]) promise to increase efficiency, but will be driven as hard as possible. This creates challenges for thermal management and reliability.

  12. Power balance equation in electron beam evaporation process

    International Nuclear Information System (INIS)

    Blumenfeld, L.; Soubbaramayer.

    1994-01-01

    The aim of the paper is to solve the equation giving the total power of the gun, used in the electron beam evaporation process, in terms of the power used to generated the vapor stream and the three main power losses due to three parasite phenomena: turbulent thermal convection in the molten pool, electron back scattering and heat radiation from the vapor emitting surface. Scaling laws are first reviewed and results are given with the example of the evaporation of aluminium with a 5 kW axisymmetric gun working in steady state mode. The influence of an applied magnetic field on the evaporation rate is also examined. 5 refs., 3 figs., 1 tab

  13. Study and Handling Methods of Power IGBT Module Failures in Power Electronic Converter Systems

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Lee, Kyo-Beum

    2015-01-01

    Power electronics plays an important role in a wide range of applications in order to achieve high efficiency and performance. Increasing efforts are being made to improve the reliability of power electronics systems to ensure compliance with more stringent constraints on cost, safety......, and availability in different applications. This paper presents an overview of the major failure mechanisms of IGBT modules and their handling methods in power converter systems improving reliability. The major failure mechanisms of IGBT modules are presented first, and methods for predicting lifetime...... and estimating the junction temperature of IGBT modules are then discussed. Subsequently, different methods for detecting open- and short-circuit faults are presented. Finally, fault-tolerant strategies for improving the reliability of power electronic systems under field operation are explained and compared...

  14. A combined source of electron bunches and microwave power

    International Nuclear Information System (INIS)

    Xie, J.L.; Wang, F.Y.; Yang, X.P.; Shen, B.; Gu, W.; Zhang, L.W.

    2003-01-01

    In this article, the possibility of using a high power klystron amplifier simultaneously as a microwave power source as usual and an electron bunches source by extracting the spent beam with a magnet and also as an oscillator by feedback is investigated. The purpose of this study is to demonstrate the feasibility of constructing a very compact electron linear accelerator or for other applications of electron bunches. The feasibility of the idea was first examined by computer simulation of the electron motion in a 5 MW klystron and the characteristics of the klystron spent beam. Experimental study was then carried out by installing a radio frequency cavity and a Faraday cage in sequence at the exit end of a bending magnet located at the top of the klystron collector. The energy and current of the chopped spent electron beam can then be measured. By properly choosing the feedback circuit elements, the frequency stability of the klystron in oscillator mode was proved to be good enough for linac operation. According to the results presented in this article, it is evident that an extremely compact linac for research and education with better affordability can be constructed to promote the applications of linacs

  15. Thermoelectric self-cooling for power electronics: Increasing the cooling power

    International Nuclear Information System (INIS)

    Martinez, Alvaro; Astrain, David; Aranguren, Patricia

    2016-01-01

    Thermoelectric self-cooling was firstly conceived to increase, without electricity consumption, the cooling power of passive cooling systems. This paper studies the combination of heat pipe exchangers and thermoelectric self-cooling, and demonstrates its applicability to the cooling of power electronics. Experimental tests indicate that source-to-ambient thermal resistance reduces by around 30% when thermoelectric self-cooling system is installed, compared to that of the heat pipe exchanger under natural convection. Neither additional electric power nor cooling fluids are required. This thermal resistance reaches 0.346 K/W for a heat flux of 24.1 kW/m"2, being one order of magnitude lower than that obtained in previous designs. In addition, the system adapts to the cooling demand, reducing this thermal resistance for increasing heat. Simulation tests have indicated that simple system modifications allow relevant improvements in the cooling power. Replacement of a thermoelectric module with a thermal bridge leads to 33.54 kW/m"2 of top cooling power. Likewise, thermoelectric modules with shorter legs and higher number of pairs lead to a top cooling power of 44.17 kW/m"2. These results demonstrate the applicability of thermoelectric self-cooling to power electronics. - Highlights: • Cooling power of passive systems increased. • No electric power consumption. • Applicable for the cooling of power electronics. • Up to 44.17 kW/m"2 of cooling power, one order of magnitude higher. • Source-to-ambient thermal resistance reduces by 30%.

  16. State of the art of High Temperature Power Electronics

    OpenAIRE

    Buttay , Cyril; Planson , Dominique; Allard , Bruno; Bergogne , Dominique; Bevilacqua , Pascal; Joubert , Charles; Lazar , Mihai; Martin , Christian; Morel , Hervé; Tournier , Dominique; Raynaud , Christophe

    2009-01-01

    International audience; High temperature power electronics has become possible with the recent availability of silicon carbide devices. This material, as other wide-bandgap semiconductors, can operate at temperatures above 500°C, whereas silicon is limited to 150-200°C. Applications such as transportation or deep oil and gas wells drilling can benefit. A few converters operating above 200°C have been demonstrated, but work is still ongoing to design and build a power system able to operate in...

  17. Cyber Physical Systems Approach to Power Electronics Education

    Directory of Open Access Journals (Sweden)

    Marko Vekić

    2012-12-01

    Full Text Available This paper proposes a Cyber Physical Approach (CPS to power electronics (PE education where all aspects of PE technology from circuit topology to the implementation of real time control code on a microprocessor are dealt with as an inseparable whole, and only the system complexity is increased during the course of instruction. This approach is now made practical thanks to the affordable and unrestricted access to high-power PE laboratory infrastructure (PE laboratory in a box in the form of high-fidelity digital PE emulators with 1us calculation time step and latency.

  18. Editorial for IEEE Transactions on Power Electronics, January 2013

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Lehman, Brad

    2013-01-01

    should increase the impact factor of the IEEE TRANSACTIONS ON POWER ELECTRONICS (TPEL). In 2007, TPEL published 2600 pages, and it has gradually been increased to 4000 pages in 2011, 5000 pages in 2012, and 5500 pages are projected for 2013. We have decided to publish 12 printed issues so every month...... a new issue will be printed. A graph is provided showing the number of regular papers received in the past years as well as the number of published pages in the TPEL. Finally they note that in 2008, TPEL obtained a record high value for the impact factor (as shown in a figure) but in 2009 it was reduced...... the papers to be read over a longer time span; 2) Web of Science (ISI Thomsen Reuter) began to register new power electronics conferences in their database, and citations from conferences counts and contributes to a higher impact factor....

  19. High power electron beam accelerators for gas laser excitation

    International Nuclear Information System (INIS)

    Kelly, J.G.; Martin, T.H.; Halbleib, J.A.

    1976-06-01

    A preliminary parameter investigation has been used to determine a possible design of a high-power, relativistic electron beam, transversely excited laser. Based on considerations of present and developing pulsed power technology, broad area diode physics and projected laser requirements, an exciter is proposed consisting of a Marx generator, pulse shaping transmission lines, radially converging ring diodes and a laser chamber. The accelerator should be able to deliver approximately 20 kJ of electron energy at 1 MeV to the 10 4 cm 2 cylindrical surface of a laser chamber 1 m long and 0.3 m in diameter in 24 ns with very small azimuthal asymmetry and uniform radial deposition

  20. Power Electronics Thermal Management Research: Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-10-19

    The objective for this project is to develop thermal management strategies to enable efficient and high-temperature wide-bandgap (WBG)-based power electronic systems (e.g., emerging inverter and DC-DC converter). Reliable WBG devices are capable of operating at elevated temperatures (≥ 175 °Celsius). However, packaging WBG devices within an automotive inverter and operating them at higher junction temperatures will expose other system components (e.g., capacitors and electrical boards) to temperatures that may exceed their safe operating limits. This creates challenges for thermal management and reliability. In this project, system-level thermal analyses are conducted to determine the effect of elevated device temperatures on inverter components. Thermal modeling work is then conducted to evaluate various thermal management strategies that will enable the use of highly efficient WBG devices with automotive power electronic systems.

  1. Power Electronic Transformer based Three-Phase PWM AC Drives

    Science.gov (United States)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  2. Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues

    International Nuclear Information System (INIS)

    Yang, M; Zhu, X R; Mohan, R; Dong, L; Virshup, G; Clayton, J

    2010-01-01

    We discovered an empirical relationship between the logarithm of mean excitation energy (ln I m ) and the effective atomic number (EAN) of human tissues, which allows for computing patient-specific proton stopping power ratios (SPRs) using dual-energy CT (DECT) imaging. The accuracy of the DECT method was evaluated for 'standard' human tissues as well as their variance. The DECT method was compared to the existing standard clinical practice-a procedure introduced by Schneider et al at the Paul Scherrer Institute (the stoichiometric calibration method). In this simulation study, SPRs were derived from calculated CT numbers of known material compositions, rather than from measurement. For standard human tissues, both methods achieved good accuracy with the root-mean-square (RMS) error well below 1%. For human tissues with small perturbations from standard human tissue compositions, the DECT method was shown to be less sensitive than the stoichiometric calibration method. The RMS error remained below 1% for most cases using the DECT method, which implies that the DECT method might be more suitable for measuring patient-specific tissue compositions to improve the accuracy of treatment planning for charged particle therapy. In this study, the effects of CT imaging artifacts due to the beam hardening effect, scatter, noise, patient movement, etc were not analyzed. The true potential of the DECT method achieved in theoretical conditions may not be fully achievable in clinical settings. Further research and development may be needed to take advantage of the DECT method to characterize individual human tissues.

  3. Technology and Power. A Foucauldian Analysis of Electronic Monitoring Discourses

    OpenAIRE

    Anna Vitores; Miquel Domènech

    2007-01-01

    The article aims to show the importance of FOUCAULT within social studies of science and technology. It also illustrates how a Foucauldian analysis can be useful for studies of science, technology and society focused on power effects. To accomplish these objectives we analyze the emergence of a specific techno-scientific innovation: the electronic monitoring of offenders. We map the discontinuities and discourse dispersions linked to those practices that constitute different materializations ...

  4. Development of an electron gun for high power CW electron linac

    International Nuclear Information System (INIS)

    Yamazaki, Yoshio; Nomura, Masahiro

    1994-01-01

    An electron gun launching high average current beam has been designed for the high power CW electron linac at PNC. A peak electron beam current of 400mA with beam energy 200keV is required from the buncher design. However its average current is very high(duty factor 20%), a mesh grid is not able to be used for current control because of heating up or melting of grid. Furthermore, the beam current have to be variable up to 400mA to match with downstream modules, especially the accelerating guides including recirculating system. We employed the electron gun with two aperture grids to control beam current. The dimension of the electrodes, electron trajectory, the size of beam radius, and gun emittance was simulated by EGUN. (author)

  5. Technology and Power. A Foucauldian Analysis of Electronic Monitoring Discourses

    Directory of Open Access Journals (Sweden)

    Anna Vitores

    2007-05-01

    Full Text Available The article aims to show the importance of FOUCAULT within social studies of science and technology. It also illustrates how a Foucauldian analysis can be useful for studies of science, technology and society focused on power effects. To accomplish these objectives we analyze the emergence of a specific techno-scientific innovation: the electronic monitoring of offenders. We map the discontinuities and discourse dispersions linked to those practices that constitute different materializations of this electronic device. Because we start from questions concerning power technologies, rather than simply analyzing the ideologies and knowledges that legitimate electronic monitoring and its technical reliability, we attend to the assemblage of discourses, rhetorics, vocabularies, techniques and procedures by which knowledge is intertwined and joins with the exercise of power. In this way, we show how one of FOUCAULT's technologies of power—disciplinary technology—is articulated, nourished and contradicted by other emergent logics drawing on new forms of regulation and social control. URN: urn:nbn:de:0114-fqs070225

  6. Vector analyzing power in elastic electron-proton scattering

    International Nuclear Information System (INIS)

    Diaconescu, L.; Ramsey-Musolf, M.J.

    2004-01-01

    We compute the vector analyzing power (VAP) for the elastic scattering of transversely polarized electrons from protons at low energies using an effective theory of electrons, protons, and photons. We study all contributions through second order in E/M, where E and M are the electron energy and nucleon mass, respectively. The leading-order VAP arises from the imaginary part of the interference of one- and two-photon exchange amplitudes. Subleading contributions are generated by the nucleon magnetic moment and charge radius as well as recoil corrections to the leading-order amplitude. Working to O(E/M) 2 , we obtain a prediction for A n that is free of unknown parameters and that agrees with the recent measurement of the VAP in backward angle ep scattering

  7. Human Powered PiezoelectricBatteries to Supply Power to Wearable Electronic Devices.

    OpenAIRE

    Gonzalez, Jose' Luis; Rubio, Antonio; Moll, Francesc

    2002-01-01

    Consumer electronic equipments are becoming small, portable devices that provide users with a wide range of functionality, from communication to music playing. The battery technology and the power consumption of the device limit the size, weight and autonomous lifetime. One promising alternative to batteries (and fuel cells, that must be refueled as well) is to use the parasitic energy dissipated in the movement of the wearer of the device to power it. We analyze in this work the current stat...

  8. Overview on thermal and mechanical challenges of high power RF electronic packaging

    NARCIS (Netherlands)

    Yuan, C.A.; Kregting, R.; Driel, W. van; Gielen, A.W.J.; Xiao, A.; Zhang, G.Q.

    2011-01-01

    High Power RF electronics is one of the essential parts for wireless communication, including the personal communication, broadcasting, microwave radar, etc. Moreover, high efficient high power electronics has entered the ISM market, such as the power generator of microwave oven. Power electronics

  9. Reliability analysis of grid connected small wind turbine power electronics

    International Nuclear Information System (INIS)

    Arifujjaman, Md.; Iqbal, M.T.; Quaicoe, J.E.

    2009-01-01

    Grid connection of small permanent magnet generator (PMG) based wind turbines requires a power conditioning system comprising a bridge rectifier, a dc-dc converter and a grid-tie inverter. This work presents a reliability analysis and an identification of the least reliable component of the power conditioning system of such grid connection arrangements. Reliability of the configuration is analyzed for the worst case scenario of maximum conversion losses at a particular wind speed. The analysis reveals that the reliability of the power conditioning system of such PMG based wind turbines is fairly low and it reduces to 84% of initial value within one year. The investigation is further enhanced by identifying the least reliable component within the power conditioning system and found that the inverter has the dominant effect on the system reliability, while the dc-dc converter has the least significant effect. The reliability analysis demonstrates that a permanent magnet generator based wind energy conversion system is not the best option from the point of view of power conditioning system reliability. The analysis also reveals that new research is required to determine a robust power electronics configuration for small wind turbine conversion systems.

  10. Electron Acceleration by High Power Radio Waves in the Ionosphere

    Science.gov (United States)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  11. Design of power electronics for TVC EMA systems

    Science.gov (United States)

    Nelms, R. Mark

    1993-08-01

    The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

  12. Large power electron tubes for high frequency heating

    International Nuclear Information System (INIS)

    Okamoto, Tadashi; Sato, Hisaaki.

    1988-01-01

    On the large power electron tubes used for electron cyclotron heating, lower hybrid resonance frequency heating, and ion cyclotron range of frequency heating, namely gyrotron, klystron and quadrupole tube, the features, the present status of development, the construction, the principle and so on are explained. The research and development of gyrotrons are most advanced in USSR, the inventor. The course of the development of gyrotrons in foreign countries and in Japan is described. There are many variants of gyrotrons, for example whispering gallery mode, klystron type, backward wave oscillator type, gyro-peniotron and others. The principle of gyrotrons is explained, and about the examples of the developed gyrotrons, the design parameters are shown. For the purpose of using for the LHRF heating in JT-60, a superlarge power klystron of 1 MW output at 2 GHz frequency, which is the largest class in the world, has been developed. Its total length is 2.7 m, and weight is 1.5 t. It features, construction, function and performance are reported. The trend of large power quadrupole tubes is toward stable action with large power in VHF zone, and the typical products in USA and Europe are shown. (Kako, I.)

  13. Dimmable electronic ballasts by variable power density modulation technique

    Science.gov (United States)

    Borekci, Selim; Kesler, Selami

    2014-11-01

    Dimming can be accomplished commonly by switching frequency and pulse density modulation techniques and a variable inductor. In this study, a variable power density modulation (VPDM) control technique is proposed for dimming applications. A fluorescent lamp is operated in several states to meet the desired lamp power in a modulation period. The proposed technique has the same advantages of magnetic dimming topologies have. In addition, a unique and flexible control technique can be achieved. A prototype dimmable electronic ballast is built and experiments related to it have been conducted. As a result, a 36WT8 fluorescent lamp can be driven for a desired lamp power from several alternatives without modulating the switching frequency.

  14. Power Electronics as Efficient Interface of Renewable Energy Sources

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe; Kjær, Søren Bækhøj

    2004-01-01

    The global electrical energy consumption is steadily rising and consequently there is a demand to increase the power generation capacity. A significant percentage of the required capacity increase can be based on renewable energy sources. Wind turbine technology, as the most cost effective...... renewable energy conversion system, will play an important part in our future energy supply. But other sources like microturbines, photovoltaics and fuel cell systems may also be serious contributor to the power supply. Characteristically, power electronics will be an efficient and important interface...... to the grid and this paper will first briefly discuss three different alternative/ renewable energy sources. Next, various configurations of the wind turbine technology are presented, as this technology seems to be most developed and cost-effective. Finally, the developments and requirements from the grid...

  15. A Review of the State of the Art of Power Electronics for Wind Turbines

    DEFF Research Database (Denmark)

    Chen, Zhe; Guerrero, Josep M.; Blaabjerg, Frede

    2009-01-01

    are summarized and the possible uses of power electronic converters with wind farms are shown. Finally, the possible methods of using the power electronic technology for improving wind turbine performance in power systems to meet the main grid connection requirements are discussed.......This paper reviews the power electronic applications for wind energy systems. Various wind turbine systems with different generators and power electronic converters are described, and different technical features are compared. The electrical topologies of wind farms with different wind turbines...

  16. Stop smoking support programs

    Science.gov (United States)

    Smokeless tobacco - stop smoking programs; Stop smoking techniques; Smoking cessation programs; Smoking cessation techniques ... You can find out about smoking cessation programs from: Your ... Your employer Your local health department The National Cancer ...

  17. Calorimetric Measuring Systems for Characterizing High Frequency Power Losses in Power Electronic Components and Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Pedersen, John Kim; Ritchie, Andrew Ewen

    2002-01-01

    High frequency power losses in power electronic components and systems are very difficult to measure. The same applies to the efficiency of high-efficiency systems and components. An important method to measure losses with high accuracy is the calorimetric measuring systems. This paper describes...... to calibrate such systems are proposed and different applications of the system are given. Two practical examples end the description of the research. It is concluded that such systems have a relative long time-constant but they are accurate and useful for precise power loss measurement....

  18. Pulsed Power for a Dynamic Transmission Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

    dehope, w j; browning, n; campbell, g; cook, e; king, w; lagrange, t; reed, b; stuart, b; Shuttlesworth, R; Pyke, B

    2009-06-25

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM.

  19. Pulsed Power for a Dynamic Transmission Electron Microscope

    International Nuclear Information System (INIS)

    DeHope, W.J.; Browning, N.; Campbell, G.; Cook, E.; King, W.; Lagrange, T.; Reed, B.; Stuart, B.; Shuttlesworth, R.; Pyke, B.

    2009-01-01

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM

  20. Maximum wind energy extraction strategies using power electronic converters

    Science.gov (United States)

    Wang, Quincy Qing

    2003-10-01

    This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

  1. Power-Electronics Issues of Modern Electric Railway Systems

    Directory of Open Access Journals (Sweden)

    STEIMEL, A.

    2010-05-01

    Full Text Available After de-regulation of the former state-owned railways and severe restructuring of the railway industry in the last 15 years, more innovative vehicle concepts saw the light of the day. Power electronics, already formerly being a pacemaker for progress of traction vehicles, brought forth an utmost standardization of the main drive by means of the IGBT-converter-fed induction motor drive. This is independent of the railway supply voltage system or of a diesel prime mover, for locomotives, high-speed and mass-transit trains as well as for tramways. Vehicles able to operate on all four European railway voltage systems have become feasible and are used now widely. New trends as Permanent-Magnet Synchronous Motors or Medium-Frequency Transformers are discussed, and a short overlook over actual field-oriented high-performance motor control systems - including a speed-sensorless variant - is given. Power electronics dominates the field of conversion of the 16.7-Hz railway supply power, typical for Central Europe, from the 50-Hz three-phase utility grid.

  2. TU-FG-BRB-02: The Impact of Using Dual-Energy CT for Determining Proton Stopping Powers: Comparison Between Theory and Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Baer, E; Jee, K [Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Zhang, R; Yang, K; Sharp, G; Liu, B [Massachusetts General Hospital, Boston, MA (United States); Lalonde, A [University of Montreal, Montreal, QC (Canada); Royle, G [University College London, London, London (United Kingdom); Bouchard, H [Universite de Montreal, Montreal, QC (Canada); Lu, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: To evaluate the clinical performance of dual-energy CT (DECT) in determining proton stopping power ratios (SPR) and demonstrate advantages over conventional single-energy CT (SECT). Methods: SECT and DECT scans of tissue-equivalent plastics as well as animal meat samples are performed with a Siemens SOMATOM Definition Flash. The methods of Schneider et al. (1996) and Bourque et al. (2014) are used to determine proton SPR on SECT and DECT images, respectively. Waterequivalent path length (WEPL) measurements of plastics and tissue samples are performed with a 195 MeV proton beam. WEPL values are determined experimentally using the depth-dose shift and dose extinction methods. Results: Comparison between CT-based and experimental WEPL is performed for 12 tissue-equivalent plastic as well as 6 meat boxes containing animal liver, kidney, heart, stomach, muscle and bones. For plastic materials, results show a systematic improvement in determining SPR with DECT, with a mean absolute error of 0.4% compared to 1.7% for SECT. For the meat samples, preliminary results show the ability for DECT to determine WEPL with a mean absolute value of 1.1% over all meat boxes. Conclusion: This work demonstrates the potential in using DECT for determining proton SPR with plastic materials in a clinical context. Further work is required to show the benefits of DECT for tissue samples. While experimental uncertainties could be a limiting factor to show the benefits of DECT over SECT for the meat samples, further work is required to adapt the DECT formalism in the context of clinical use, where noise and artifacts play an important role.

  3. TU-FG-BRB-02: The Impact of Using Dual-Energy CT for Determining Proton Stopping Powers: Comparison Between Theory and Experiments

    International Nuclear Information System (INIS)

    Baer, E; Jee, K; Zhang, R; Yang, K; Sharp, G; Liu, B; Lalonde, A; Royle, G; Bouchard, H; Lu, H

    2016-01-01

    Purpose: To evaluate the clinical performance of dual-energy CT (DECT) in determining proton stopping power ratios (SPR) and demonstrate advantages over conventional single-energy CT (SECT). Methods: SECT and DECT scans of tissue-equivalent plastics as well as animal meat samples are performed with a Siemens SOMATOM Definition Flash. The methods of Schneider et al. (1996) and Bourque et al. (2014) are used to determine proton SPR on SECT and DECT images, respectively. Waterequivalent path length (WEPL) measurements of plastics and tissue samples are performed with a 195 MeV proton beam. WEPL values are determined experimentally using the depth-dose shift and dose extinction methods. Results: Comparison between CT-based and experimental WEPL is performed for 12 tissue-equivalent plastic as well as 6 meat boxes containing animal liver, kidney, heart, stomach, muscle and bones. For plastic materials, results show a systematic improvement in determining SPR with DECT, with a mean absolute error of 0.4% compared to 1.7% for SECT. For the meat samples, preliminary results show the ability for DECT to determine WEPL with a mean absolute value of 1.1% over all meat boxes. Conclusion: This work demonstrates the potential in using DECT for determining proton SPR with plastic materials in a clinical context. Further work is required to show the benefits of DECT for tissue samples. While experimental uncertainties could be a limiting factor to show the benefits of DECT over SECT for the meat samples, further work is required to adapt the DECT formalism in the context of clinical use, where noise and artifacts play an important role.

  4. Optimum size of a calibration phantom for x-ray CT to convert the Hounsfield units to stopping power ratios in charged particle therapy treatment planning.

    Science.gov (United States)

    Inaniwa, T; Tashima, H; Kanematsu, N

    2018-03-01

    In charged-particle therapy treatment planning, the volumetric distribution of stopping power ratios (SPRs) of body tissues relative to water is used for patient dose calculation. The distribution is conventionally obtained from computed tomography (CT) images of a patient using predetermined conversion functions from the CT numbers to the SPRs. One of the biggest uncertainty sources of patient SPR estimation is insufficient correction of beam hardening arising from the mismatch between the size of the patient cross section and the calibration phantom for producing the conversion functions. The uncertainty would be minimized by selecting a suitable size for the cylindrical water calibration phantom, referred to as an 'effective size' of the patient cross section, Leffective. We investigated the Leffective for pelvis, abdomen, thorax, and head and neck regions by simulating an ideal CT system using volumetric models of the reference male and female phantoms. The Leffective values were 23.3, 20.3, 22.7 and 18.8 cm for the pelvis, abdomen, thorax, and head and neck regions, respectively, and the Leffective for whole body was 21.0 cm. Using the conversion function for a 21.0-cm-diameter cylindrical water phantom, we could reduce the root mean square deviation of the SPRs and their mean deviation to ≤0.011 and ≤0.001, respectively, in the whole body. Accordingly, for simplicity, the effective size of 21.0 cm can be used for the whole body, irrespective of body-part regions for treatment planning in clinical practice.

  5. Advanced Power Electronic Interfaces for Distributed Energy Systems Part 1: Systems and Topologies

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, W.; Chakraborty, S.; Kroposki, B.; Thomas, H.

    2008-03-01

    This report summarizes power electronic interfaces for DE applications and the topologies needed for advanced power electronic interfaces. It focuses on photovoltaic, wind, microturbine, fuel cell, internal combustion engine, battery storage, and flywheel storage systems.

  6. Thermal Management of Power Electronics and Electric Motors for Electric-Drive Vehicles (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S.

    2014-09-01

    This presentation is an overview of the power electronics and electric motor thermal management and reliability activities at NREL. The focus is on activities funded by the Department of Energy Vehicle Technologies Office Advanced Power Electronics and Electric Motors Program.

  7. Electron diode oscillators for high-power RF generation

    International Nuclear Information System (INIS)

    Humphries, S.

    1989-01-01

    Feedback oscillators have been used since the invention of the vacuum tube. This paper describes the extension of these familiar circuits to the regime of relativistic electron beam diodes. Such devices have potential application for the generation of high power RF radiation in the range 50-250 MHz, 1-10 GW with 20-60% conversion efficiency. This paper reviews the theory of the oscillator and the results of a design study. Calculations for the four-electrode diode with EGUN and EBQ show that good modulations of 30 kA electron beam at 600 kV can be achieved with moderate field stress on the electrodes. Conditions for oscillation have been studied with an in-house transmission line code. A design for a 7.5 GW oscillator at 200 MHz with 25% conversion efficiency is presented

  8. Applications and research on nano power electronics: an adventure beyond quantum electronics

    Science.gov (United States)

    Chakraborty, Arindam; Emadi, Ali

    2005-06-01

    This paper is a roadmap to the exhaustive role of the newly emerging field of nanotechnology in various application and research areas. Some of the today's important topics are plasma, dielectric layer semiconductor, and carbon nanoparticle based technologies. Carbon nanotubes are very useful for the purpose of fabricating nano opto power devices. The basic concept behind tunneling of electrons has been utilized to define another scope of this technology, and thus came many quantum scale tunneling devices and elements. Fabrication of crystal semiconductors of high quality along with oxides of nano aspect would give rise to superior device performance and find applications such as LEDs, LASER, VLSI technology and also in highly efficient solar cells. Many nano-research based organizations are fully devoted to develop nano power cells, which would give birth to new battery cells, tunneling devises, with high power quality, longer lives, and higher activation rates. Different electronics industries as well as the military organizations would be largely benefited due to this major component and system design ideas of 'Smart Power' technologies. The contribution of nano scale power electronics would be realized in various fields like switching devices, electromechanical systems and quantum science. Such a sophisticated technology will have great impact on the modernization of robotics; space systems, automotive systems and many other fields. The highly emerging field of nanomedicine according to specialists would bring a dramatic revolution in the present century. However nanomedicine is nothing but an integration of biology, medicine and technology. Thermoelectric materials as been referred earlier also are used in case of implantable medical equipments for generation of electric power sufficient for those equipments.

  9. Correlated ion stopping in plasmas

    International Nuclear Information System (INIS)

    Zwicknagel, G.; Deutsch, C.

    1997-01-01

    The basic features of correlated ion stopping in plasmas are demonstrated by employing two opposite extremes of cluster structures, a statistical model with a spatial ion distribution of Gaussian shape and the highly regular configuration of N-ion chains and cubic boxes. In the case of the ion chains the resonant character of correlated stopping due to the interference of the excited wake fields is discussed in detail. The general behavior of correlation effects is summarized and its dependence on the ratio of cluster size and interion spacing to the screening length in the plasma, as well as the ratio of the cluster velocity to the mean electron velocity in the target, is stressed out. The validity and applicability of the dielectric response formalism used for describing correlated stopping is critically reviewed. A scheme is presented to extend the linear formalism to weak nonlinear situations that occur, in particular, for small highly charged clusters at moderate or low velocities. For the Gaussian cluster a fit formula is given, which allows a fast and accurate calculation of the enhancement of stopping due to correlation effects and applies for all degrees of degeneracy of the electrons and arbitrary cluster velocities. copyright 1997 The American Physical Society

  10. Final Technical Report for Photovoltaic Power Electronics Research Initiative (PERI)

    Energy Technology Data Exchange (ETDEWEB)

    Amirahmadi, Ahmadreza [Univ. of Central Florida, Orlando, FL (United States); Jordan, Charlie [Univ. of Central Florida, Orlando, FL (United States); batarseh, Issa [Univ. of Central Florida, Orlando, FL (United States)

    2015-08-31

    The Power Electronics team at the University of Central Florida (UCF) has developed a novel three-phase micro-inverter for photovoltaic (PV) distributed applications. Based on a new advanced topology and control methodology, the developed inverter is small in size, and achieved DoE targeted power density, cost and efficiency specifications. Today’s inverters are widely used in PV based energy harvesting systems, but are based on single-phase design with limited application to large installations. These micro-inverters have been shown to have advantageous over their string inverter counterparts in both grid-tied PV energy harvesting and standalone micro-grid systems with energy storage. Some of these are simplified installation, no high voltage DC wiring, no single point of failure and improved energy harvesting. Several patents have been issued and this new solar conversion technology has been licensed to the private sector.

  11. Symmetric low-voltage powering system for relativistic electronic devices

    International Nuclear Information System (INIS)

    Agafonov, A.V.; Lebedev, A.N.; Krastelev, E.G.

    2005-01-01

    A special driver for double-sided powering of relativistic magnetrons and several methods of localized electron flow forming in the interaction region of relativistic magnetrons are proposed and discussed. Two experimental installations are presented and discussed. One of them is designed for laboratory research and demonstration experiments at a rather low voltage. The other one is a prototype of a full-scale installation for an experimental research at relativistic levels of voltages on the microwave generation in the new integrated system consisting of a relativistic magnetron and symmetrical induction driver

  12. Fuse Modeling for Reliability Study of Power Electronic Circuits

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Iannuzzo, Francesco; Blaabjerg, Frede

    2017-01-01

    This paper describes a comprehensive modeling approach on reliability of fuses used in power electronic circuits. When fuses are subjected to current pulses, cyclic temperature stress is introduced to the fuse element and will wear out the component. Furthermore, the fuse may be used in a large......, and rated voltage/current are opposed to shift in time to effect early breaking during the normal operation of the circuit. Therefore, in such cases, a reliable protection required for the other circuit components will not be achieved. The thermo-mechanical models, fatigue analysis and thermo...

  13. Diamond-based heat spreaders for power electronic packaging applications

    Science.gov (United States)

    Guillemet, Thomas

    As any semiconductor-based devices, power electronic packages are driven by the constant increase of operating speed (higher frequency), integration level (higher power), and decrease in feature size (higher packing density). Although research and innovation efforts have kept these trends continuous for now more than fifty years, the electronic packaging technology is currently facing a challenge that must be addressed in order to move toward any further improvements in terms of performances or miniaturization: thermal management. Thermal issues in high-power packages strongly affect their reliability and lifetime and have now become one of the major limiting factors of power modules development. Thus, there is a strong need for materials that can sustain higher heat flux levels while safely integrating into the electronic package architecture. In such context, diamond is an attractive candidate because of its outstanding thermal conductivity, low thermal expansion, and high electrical resistivity. Its low heat capacity relative to metals such as aluminum or copper makes it however preferable for heat spreading applications (as a heat-spreader) rather than for dissipating the heat flux itself (as a heat sink). In this study, a dual diamond-based heat-spreading solution is proposed. Polycrystalline diamond films were grown through laser-assisted combustion synthesis on electronic substrates (in the U.S) while, in parallel, diamond-reinforced copper-matrix composite films were fabricated through tape casting and hot pressing (in France). These two types of diamond-based heat-spreading films were characterized and their microstructure and chemical composition were related to their thermal performances. Particular emphasize was put on the influence of interfaces on the thermal properties of the materials, either inside a single material (grain boundaries) or between dissimilar materials (film/substrate interface, matrix/reinforcement interface). Finally, the packaging

  14. Low power signal processing electronics for wearable medical devices.

    Science.gov (United States)

    Casson, Alexander J; Rodriguez-Villegas, Esther

    2010-01-01

    Custom designed microchips, known as Application Specific Integrated Circuits (ASICs), offer the lowest possible power consumption electronics. However, this comes at the cost of a longer, more complex and more costly design process compared to one using generic, off-the-shelf components. Nevertheless, their use is essential in future truly wearable medical devices that must operate for long periods of time from physically small, energy limited batteries. This presentation will demonstrate the state-of-the-art in ASIC technology for providing online signal processing for use in these wearable medical devices.

  15. Power electronics for renewable and distributed energy systems a sourcebook of topologies, control and integration

    CERN Document Server

    Chakraborty, Sudipta; Kramer, William E

    2013-01-01

    While most books approach power electronics and renewable energy as two separate subjects, Power Electronics for Renewable and Distributed Energy Systems takes an integrative approach; discussing power electronic converters topologies, controls and integration that are specific to the renewable and distributed energy system applications. An overview of power electronic technologies is followed by the introduction of various renewable and distributed energy resources that includes photovoltaics, wind, small hydroelectric, fuel cells, microturbines and variable speed generation. Energy storage s

  16. Economic impacts of power electronics on electricity distribution systems

    International Nuclear Information System (INIS)

    Duarte, Carlos Henrique; Schaeffer, Roberto

    2010-01-01

    To achieve more efficient energy use, power electronics (PEs) may be employed. However, these introduce nonlinear loads (NLLs) into the system by generating undesired frequencies that are harmonic in relation to (multiples of) the fundamental frequency (60 Hz in Brazil). Consequently, devices using PEs are more efficient but also contribute significantly to degradation of power quality. Besides this, both the conventional rules on design and operation of power systems and the usual premises followed in energy efficiency programs (without mentioning the electricity consumed by the devices themselves) consider the sinusoidal voltage and current waveforms at the fixed fundamental frequency of the power grid. Thus, analysis of electricity consumption reductions in energy efficiency programs that include the use of PEs considers the reduction of kWh to the final consumer but not the additional losses caused by the increase in harmonic distortion. This article contributes to a better understanding of this problem by reporting the results of a case study of the ownership and use of television sets (TV sets) to estimate the economic impacts of residential PEs on a mainly residential electricity distribution system. (author)

  17. An overview of power electronic converter technology for renewable energy systems

    DEFF Research Database (Denmark)

    Chen, Zhe

    2013-01-01

    This chapter presents power electronic technology which is an enabling tool for modern wind and marine energy conversion systems. In this chapter, the main power electronic devices are described. Various power electronic converter topologies are represented, and commonly used modulation schemes...

  18. Use assessment of electronic power sources for SMAW

    Directory of Open Access Journals (Sweden)

    Scotti, A.

    1999-04-01

    Full Text Available The aim of the present work was to assess the efficacy of the use of modern technologies for power supplies in Shielded Metal Are Welding (SMAW. Coupon tests were welded by using a series of five different classes of commercial electrodes, covering their current ranges. Both a conventional electromagnetic and an electronic (inverter power sources were employed. Fusion rate, deposition efficiency, bead finish and weld geometry were measured at each experiment. Current and voltage signals were acquired at a high rate to evaluate the dynamic behavior of the power sources. The static performances of both power sources were also determined. The results showed that despite the remarkable differences between the power supplies, based on static and dynamic characterizations, no significant difference was noticed in the operational behavior of the electrodes, in the given conditions, apart from a better anti-stick performance obtained with the electronic power source.

    El objetivo del presente trabajo fue evaluar la eficacia del uso de tecnologías modernas para fuentes de energía en soldaduras con electrodo revestido (Shielded Metal Are Welding -SMAW-. Los materiales de ensayo se soldaron usando una serie de cinco clases diferentes de electrodos comerciales, cubriendo sus rangos de corriente. Para esto se utilizó una fuente de energía electromagnética convencional y una fuente de energía electrónica (inversora. La tasa de fusión, eficiencia de deposición, terminación del cordón así como el diseño de la soldadura se midieron en cada experimento. Las señales de corriente y voltaje se obtuvieron a una proporción alta para evaluar el comportamiento dinámico de las fuentes de energía. También se determinó la actuación estática de ambas fuentes. Los resultados mostraron que a pesar de las diferencias notables entre los suministros de energía, no se nota diferencia alguna significante en la conducta de trabajo de los electrodos, en

  19. The electronic stopping powers and angular energy-loss dependence of helium and lithium ions in the silicon crystal

    Czech Academy of Sciences Publication Activity Database

    Mikšová, Romana; Macková, Anna; Malinský, Petr

    2017-01-01

    Roč. 406, SEP (2017), s. 179-184 ISSN 0168-583X R&D Projects: GA MŠk LM2015056; GA ČR GA15-01602S Institutional support: RVO:61389005 Keywords : energy -loss measurement * SOI material * RBS-channelling Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.109, year: 2016

  20. Calculation of the protons stopping power in water using dielectric formalism in the MELF-GOS approach; Calculo do poder de freamento de protons em agua utilizando o formalismo dieletrico na aproximacao MELF-GOS

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Franciane; Mazer, Amanda Cristina; Hormaza, Joel Mesa [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2016-07-01

    In order to calculate the stopping power of protons, there are many very successful models at high energies, which are extrapolated to low-energy regions. From the point of view of application of proton beam in cancer treatment is just this low energy region the most relevant due to the dose deposition profile in depth for protons. In this work, we present a calculation of the stopping power of protons in a water target using the dielectric formalism in MELF-GOS approach. The results when compared to other models show good agreement for energies above 100 keV and lower values below this energy. This result should impact the range of values of protons and the Bragg peak position. (author)

  1. STOPOW/82 program for calculations of stopping powers and ranges for heavy ions in the energy range from 1 keV to 10 GeV/a.m.u

    International Nuclear Information System (INIS)

    Henniger, J.; Horlbeck, B.

    1983-01-01

    The program ST0POW/82 is created to calculate the stopping power and range of ions up to uranium in the energy range 1 keV/a. m. u. - 10 GeV/a. m. u. in any amorphous matter. The program is based on Ziegler's catalogue data and Ahlen's theoretical treatments. The Zsub(eff)sup(3) relativistic Bloch and Mott corrections and corrections on density effect are taken into account in the calculations. An opportunity of 9 different functions removal, derivative on the stopping power and range, for example, primary ionization and LET, and also of ion parameters, such as β, Zsub(eff)sup(2)/βsup(2) is foreseen. The program is written in FORTRAN language in version for the CDC-6500 computer. The program needs a minimized input also for compound targets. So it is useful for many problems in applied sciences and experimental physics

  2. The propagation of high power CW scanning electron beam in air

    International Nuclear Information System (INIS)

    Korenev, Sergey; Korenev, Ivan

    2002-01-01

    The question of propagation of high power electron beam in air presents the scientific and applied interests. The high power (80 kW) CW electron accelerator 'Rhodotron' with kinetic energy of electrons 5 and 10 MeV was used in the experiments. The experimental results for propagation of scanning electron beams in air are presented and discussed

  3. Extended Pulse-Powered Humidity-Freeze Cycling for Testing Module-Level Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, Peter L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kempe, Michael D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Repins, Ingrid L [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-28

    An EMI suppression capacitor (polypropylene film type) failed by 'popcorning' due to vapor outgassing in pulse powered humidity-freeze cycles. No shorts or shunts could be detected despite mildly corroded metallization visible in the failed capacitor. Humidity-freeze cycling is optimized to break into moisture barriers. However, further studies will be required on additional module level power electronic (MLPE) devices to optimize the stress testing for condensation to precipitate any weakness to short circuiting and other humidity/bias failure modes.

  4. Design, simulation and construction of quadrupole magnets for focusing electron beam in powerful industrial electron accelerator

    Directory of Open Access Journals (Sweden)

    S KH Mousavi

    2015-09-01

    Full Text Available In this paper the design and simulation of quadrupole magnets and electron beam optical of that by CST Studio code has been studied. Based on simulation result the magnetic quadrupole has been done for using in beam line of first Iranian powerful electron accelerator. For making the suitable magnetic field the effects of material and core geometry and coils current variation on quadrupole magnetic field have been studied. For test of quadrupole magnet the 10 MeV beam energy and 0.5 pi mm mrad emittance of input beam has been considered. We see the electron beam through the quadrupole magnet focus in one side and defocus in other side. The optimum of distance between two quadrupole magnets for low emittance have been achieved. The simulation results have good agreement with experimental results

  5. A Learning Aid Tool for Power Electronics Converters

    Directory of Open Access Journals (Sweden)

    O. Bouketir

    2005-06-01

    Full Text Available It is known that power electronics and its related subjects are not easy to understand for students taking them for first time. This is due to nature of the subjects which involve many areas and disciplines. The introduction of general purpose simulation package has helped the student a step further in understanding this subject. However, because of the generality of these tools and their drag-and drop and ad-hoc features, the students still face problems in designing a converter circuit. In this paper, the problem above is addressed by introducing a learning aid tool that guides the student over prescribed steps to design a power electronics circuit. The tool is knowledge-based system where its knowledge base encompasses two types of knowledge; topologies and switching devices. The first step in the design procedure is the selection of the application of the desired circuit. Then few steps are to be followed to come out with the appropriate topology with the optimum switching devices and parameters. System structure, its different modules and the detailed design procedure are explained in this paper

  6. The Influence of Power on Trading Partner Trust in Electronic Commerce.

    Science.gov (United States)

    Ratnasingam, Pauline

    2000-01-01

    Discussion of power in electronic commerce focuses on the impact of power in the adoption of electronic data interchange. Presents a case study of Ford Motor Company in Australia that shows negative (coercive) power resulted in uncertainty, whereas positive (persuasive) power resulted in open communications, thus building trading partner trust.…

  7. Design for Reliability of Power Electronics for Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Sangwongwanich, Ariya; Blaabjerg, Frede

    2016-01-01

    Power electronics is the enabling technology for optimizing energy harvesting from renewable systems like Photovoltaic (PV) and wind power systems, and also for interfacing grid-friendly energy systems. Advancements in the power semiconductor technology (e.g., wide band-gap devices) have pushed...... the conversion efficiency of power electronics to above 98%, where however te reliability of power electronics is becoming of high concern. Therefore, it is important to design for reliable power electronic systems to lower the risks of many failures during operation; otherwise will increase the cost...... for maintenance and reputation, thus affecting the cost of PV energy. Today's PV power conversion applications require the power electronic systems with low failure rates during a service life of 20 years or even more. To achieve so, it is vital to know the main life-limiting factors of power electronic systems...

  8. Low power RF beam control electronics for the LEB

    International Nuclear Information System (INIS)

    Mestha, L.K.; Mangino, J.; Brouk, V.; Uher, T.; Webber, R.C.

    1993-05-01

    Beam Control Electronics for the Low Energy Booster (LEB) should provide a fine reference phase and frequency for the High Power RF System. Corrections applied on the frequency of the rf signal will reduce dipole synchrotron oscillations due to power supply regulation errors, errors in frequency source or errors in the cavity voltage. It will allow programmed beam radial position control throughout the LEB acceleration cycle. Furthermore the rf signal provides necessary connections during, adiabatic capture of the beam as injected into the LEB by the Linac and will guarantee LEB rf phase synchronism with the Medium Energy Booster (MEB) rf at a programmed time in the LEB cycle between a unique LEB bucket and a unique MEB bucket. We show in this paper a design and possible interfaces with other subsystems of the LEB such as the beam instrumentation, High Power RF Stations, global accelerator controls and the precision timing system. The outline of various components of the beam control system is also presented followed by some test results

  9. A Flexible Power Electronics Configuration for Coupling Renewable Energy Sources

    Directory of Open Access Journals (Sweden)

    Mattia Filippini

    2015-05-01

    Full Text Available A combination of series, parallel and multilevel power electronics has been investigated as a potential interface for two different types of renewable energy sources and in order to reach higher power levels. Renewable energy sources are typically dispersed in a territory, and sources, like wind and solar, allow small to medium-scale generation of electricity. The configuration investigated in this article aims at adapting the coupling solution to the specific generation characteristics of the renewable energy source to make it fit the electrical network. The configuration consists of a combination of three-phase multilevel converters and single-phase inverters, which are designed to provide flexibility, high power quality and high efficiency. A detailed analysis and simulation is performed to identify the properties in conjunction with the electrical grid requirements and the potential challenges encountered during operation. An optimized operation example of wind generation combined with solar PV generation is presented to exemplify the flexibility and benefits of the proposed configuration.

  10. Passive Two-Phase Cooling of Automotive Power Electronics: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, G.; Jeffers, J. R.; Narumanchi, S.; Bennion, K.

    2014-08-01

    Experiments were conducted to evaluate the use of a passive two-phase cooling strategy as a means of cooling automotive power electronics. The proposed cooling approach utilizes an indirect cooling configuration to alleviate some reliability concerns and to allow the use of conventional power modules. An inverter-scale proof-of-concept cooling system was fabricated, and tests were conducted using the refrigerants hydrofluoroolefin HFO-1234yf and hydrofluorocarbon HFC-245fa. Results demonstrated that the system can dissipate at least 3.5 kW of heat with 250 cm3 of HFC-245fa. An advanced evaporator design that incorporates features to improve performance and reduce size was conceived. Simulation results indicate its thermal resistance can be 37% to 48% lower than automotive dual side cooled power modules. Tests were also conducted to measure the thermal performance of two air-cooled condensers--plain and rifled finned tube designs. The results combined with some analysis were then used to estimate the required condenser size per operating conditions and maximum allowable system (i.e., vapor and liquid) temperatures.

  11. Thermal Management and Reliability of Power Electronics and Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, Sreekant

    2016-08-03

    Increasing the number of electric-drive vehicles (EDVs) on America's roads has been identified as a strategy with near-term potential for dramatically decreasing the nation's dependence on oil -- by the U.S. Department of Energy, the federal cross-agency EV-Everywhere Challenge, and the automotive industry. Mass-market deployment will rely on meeting aggressive technical targets, including improved efficiency and reduced size, weight, and cost. Many of these advances will depend on optimization of thermal management. Effective thermal management is critical to improving the performance and ensuring the reliability of EDVs. Efficient heat removal makes higher power densities and lower operating temperatures possible, and in turn enables cost and size reductions. The National Renewable Energy Laboratory (NREL), along with DOE and industry partners is working to develop cost-effective thermal management solutions to increase device and component power densities. In this presentation, the activities in recent years related to thermal management and reliability of automotive power electronics and electric machines will be presented.

  12. Thermal Management and Reliability of Power Electronics and Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, Sreekant

    2016-06-13

    Increasing the number of electric-drive vehicles (EDVs) on America's roads has been identified as a strategy with near-term potential for dramatically decreasing the nation's dependence on oil - by the U.S. Department of Energy, the federal cross-agency EV-Everywhere Challenge, and the automotive industry. Mass-market deployment will rely on meeting aggressive technical targets, including improved efficiency and reduced size, weight, and cost. Many of these advances will depend on optimization of thermal management. Effective thermal management is critical to improving the performance and ensuring the reliability of EDVs. Efficient heat removal makes higher power densities and lower operating temperatures possible, and in turn enables cost and size reductions. The National Renewable Energy Laboratory (NREL), along with DOE and industry partners is working to develop cost-effective thermal management solutions to increase device and component power densities. In this presentation, the activities in recent years related to thermal management and reliability of automotive power electronics and electric machines are presented.

  13. Photovoltaic Shading Testbed for Module-Level Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Deline, C.; Meydbray, J.; Donovan, M.; Forrest, J.

    2012-05-01

    This document describes a repeatable test procedure that attempts to simulate shading situations, as would be experienced by typical residential rooftop photovoltaic (PV) systems. This type of shading test is particularly useful to evaluate the impact of different power conversion setups, including microinverters, DC power optimizers and string inverters, on overall system performance. The performance results are weighted based on annual estimates of shade to predict annual performance improvement. A trial run of the test procedure was conducted with a side by side comparison of a string inverter with a microinverter, both operating on identical 8kW solar arrays. Considering three different shade weighting conditions, the microinverter was found to increase production by 3.7% under light shading, 7.8% under moderate shading, and 12.3% under heavy shading, relative to the reference string inverter case. Detail is provided in this document to allow duplication of the test method at different test installations and for different power electronics devices.

  14. Advanced Power Electronics Interfaces for Distributed Energy Workshop Summary: August 24, 2006, Sacramento, California

    Energy Technology Data Exchange (ETDEWEB)

    Treanton, B.; Palomo, J.; Kroposki, B.; Thomas, H.

    2006-10-01

    The Advanced Power Electronics Interfaces for Distributed Energy Workshop, sponsored by the California Energy Commission Public Interest Energy Research program and organized by the National Renewable Energy Laboratory, was held Aug. 24, 2006, in Sacramento, Calif. The workshop provided a forum for industry stakeholders to share their knowledge and experience about technologies, manufacturing approaches, markets, and issues in power electronics for a range of distributed energy resources. It focused on the development of advanced power electronic interfaces for distributed energy applications and included discussions of modular power electronics, component manufacturing, and power electronic applications.

  15. Development of an electron gun for high power CW electron linac (1). Beam experiment for basic performance of electron gun

    International Nuclear Information System (INIS)

    Yamazaki, Yoshio; Nomura, Masahiro; Komata, Tomoki

    1999-05-01

    Presently, the Beam Group of Oarai Engineering Center in Japan Nuclear Cycle Development Institute (JNC) completed the high power CW electron linac. Then we started full-scale beam experiments after the government permission for a radiation equipment had given last January. Measurements of basic performance for the mesh-grid type electron gun have been done to launch stable beam at 300 mA peak current downstream of the accelerator. These experiments disclosed to increase beam loss in the electron gun in some cases of voltage supplied the mesh-grid in spite of same beam current from gun. Consequently, we could find the best condition for mesh-grid voltage and heater current to supply stable beam at 300 mA peak current for accelerator study. (author)

  16. Stopping dynamics of ions passing through correlated honeycomb clusters

    Science.gov (United States)

    Balzer, Karsten; Schlünzen, Niclas; Bonitz, Michael

    2016-12-01

    A combined nonequilibrium Green functions-Ehrenfest dynamics approach is developed that allows for a time-dependent study of the energy loss of a charged particle penetrating a strongly correlated system at zero and finite temperatures. Numerical results are presented for finite inhomogeneous two-dimensional Fermi-Hubbard models, where the many-electron dynamics in the target are treated fully quantum mechanically and the motion of the projectile is treated classically. The simulations are based on the solution of the two-time Dyson (Keldysh-Kadanoff-Baym) equations using the second-order Born, third-order, and T -matrix approximations of the self-energy. As application, we consider protons and helium nuclei with a kinetic energy between 1 and 500 keV/u passing through planar fragments of the two-dimensional honeycomb lattice and, in particular, examine the influence of electron-electron correlations on the energy exchange between projectile and electron system. We investigate the time dependence of the projectile's kinetic energy (stopping power), the electron density, the double occupancy, and the photoemission spectrum. Finally, we show that, for a suitable choice of the Hubbard model parameters, the results for the stopping power are in fair agreement with ab initio simulations for particle irradiation of single-layer graphene.

  17. Effects of Power Tracking Algorithms on Lifetime of Power Electronic Devices Used in Solar Systems

    Directory of Open Access Journals (Sweden)

    Canras Batunlu

    2016-10-01

    Full Text Available In photovoltaic solar energy systems, power management algorithms (PMAs, usually called maximum power point tracking (MPPT algorithms, are widely used for extracting maximum available power at every point in time. However, tracking the maximum power has negative effects on the availability of solar energy systems. This is due, mainly, to the created disturbances and thermal stresses on the associated power electronic converters (PECs. This work investigates the effects of PMA on the lifetime consumption, thermal stresses and failures on DC-DC converters used in solar systems. Firstly theoretical analysis and modelling of photovoltaic solar systems including converter’s electro thermal characteristics were developed. Subsequently, experiments on photovoltaic solar systems were carried out using two different PMAs, namely, perturb and observe (P&O and incremental conductance (IC. Real-time data was collected, under different operating conditions, including thermal behavior using thermal imaging camera and dSPACE. Converters’ thermal cycling was found to be approximately 3 °C higher with the IC algorithm. The steady state temperature was 52.7 °C, for the IC while it was 42.6 °C for P&O. Although IC algorithm offers more accurate power management tool, it causes more severe thermal stresses which, in this study, has led to approximately 1.4 times greater life consumption compared to P&O.

  18. TU-FG-BRB-04: A New Optimization Method for Pre-Treatment Patient-Specific Stopping-Power by Combining Proton Radiography and X-Ray CT

    International Nuclear Information System (INIS)

    Collins-Fekete, C; Schulte, R; Beaulieu, L; Seco, J

    2016-01-01

    Purpose: The relative stopping power (RSP) uncertainty is the largest contributor to the range uncertainty in proton therapy. The purpose of this work is to develop a robust and systematic method that yields accurate patient specific RSPs by combining pre-treatment X-ray CT and daily proton radiography. Methods: The method is formulated as a penalized least squares optimization (PLSO) problem min(|Ax-B|). The matrix A represents the cumulative path-length crossed in each material computed by calculating proton trajectories through the X-ray CT. The material RSPs are denoted by x and B is the pRad, expressed as water equivalent thickness. The equation is solved using a convex-conic optimizer. Geant4 simulations were made to assess the feasibility of the method. RSP extracted from the Geant4 materials were used as a reference and the clinical HU-RSP curve as a comparison. The PLSO was first tested on a Gammex RMI-467 phantom. Then, anthropomorphic phantoms of the head, pelvis and lung were studied and resulting RSPs were evaluated. A pencil beam was generated in each phantom to evaluate the proton range accuracy achievable by using the optimized RSPs. Finally, experimental data of a pediatric head phantom (CIRS) were acquired using a recently completed experimental pCT scanner. Results: Numerical simulations showed precise RSP (<0.75%) for Gammex materials except low-density lung (LN-300) (1.2%). Accurate RSP have been obtained for the head (µ=−0.10%, 1.5σ=1.12%), lung (µ=−0.33, 1.5σ=1.02%) and pelvis anthropomorphic phantoms (µ=0.12, 1.5σ=0,99%). The range precision has been improved with an average R80 difference to the reference (µ±1.5σ) of −0.20±0.35%, −0.47±0.92% and −0.06±0.17% in the head, lung and pelvis phantoms respectively, compared to the 3.5% clinical margin. Experimental HU-RSP curve have been produced on the CIRS pediatric head. Conclusion: The proposed PLSO with prior knowledge X-ray CT shows promising potential (R80 σ<1.0% over

  19. Power stores and power electronics. Elements for a stable and reliable vehicle power supply system; Energiespeicher und Leistungselektronik. Elemente fuer ein stabiles und zuverlaessiges Bordnetz

    Energy Technology Data Exchange (ETDEWEB)

    Nalbach, Marc; Hoff, Carsten; Olk, Joachim; Schoellmann, Matthias [Hella KGaA Hueck und Co., Lippstadt (Germany); Schick, Detlef [Atmel, Garching (Germany)

    2008-07-01

    The demand for fuel efficient technologies in automotive applications is driven by the ongoing and increased CO{sub 2} discussion respective the upcoming tightening of the law as well as by the exhaustion of the worldwide oil resources. Today, micro-hybrid cars using idle stop, micro-regenerative braking and/or electrification of auxiliary components deliver a cost efficient approach within the 14V E/E energy system. Furthermore, the optimization of the components themselves like turbo-charging of the combustion engine, tyres with a low rolling friction as well as weight reduction and LED lighting has a significant impact on the car efficiency. But the implementations of idle stop plus additional innovations like electrical power steering are able to jeopardize the stability of the vehicle electrical power system by its amount of electrical energy and power consumption. Contrary, these mechatronics and actuators need a reliable power supply especially if they are safety critical. To ensure the stability of the power supply the ratio of energy storage and power resources has to be balanced within the E/E system. Within this paper the optimization of energy and power resources is shown using an exemplary application and how this approach could be extrapolated to the whole automobile power system. (orig.)

  20. Modular Power Electronic Converters in the Power Range 1 to 10 kW

    DEFF Research Database (Denmark)

    Klimczak, Pawel

    Thanks to CO2 emission reduction policies and increasing prices of fossil fuels a significant growth in field of sustainable energy sources (SES) is being observed during last decade. A government support and take-off projects in Europe and US shall ensure an increasing trend in future too. Some...... of SES based plants , like hydro-, geothermal-, biofuel-plants, use synchronous generators directly connected to the grid. But some other SES technologies, like fuel cell or photovoltaic, require a power electronic converter between the energy source and the load or the grid. Work presented...... in this thesis concentrates on dc-dc non-isolated converters suitable for high voltage gain applications, like uninterruptible power supply (UPS) and some of sustainable energy sources. A special attention is on reduction of power losses and efficiency improvements in non-isolated dc-dc step-up converters...

  1. Nuclear stopping in transmission experiments

    International Nuclear Information System (INIS)

    Glazov, Lev G.; Sigmund, Peter

    2003-01-01

    Energy-loss spectra, mean and peak energy loss, and straggling due to elastic nuclear scattering have been studied theoretically as a function of target thickness and deflection angle of an initially monochromatic and well-collimated ion beam. The goal of this work has been to provide a generally valid scheme for nuclear-stopping corrections, allowing to determine electronic-stopping forces from energy-loss spectra measured in transmission geometry. Calculations have been based on the generalized Bothe-Landau theory of energy loss and multiple scattering. Our peak energy losses at zero emergence angle show close (∼10%) agreement with predictions of Fastrup et al. on the basis of the Bohr-Williams theory. However, predicted mean and peak energy losses are found to more sensitively depend on the underlying interatomic potential than unrestricted, i.e. angle-integrated mean or peak energy losses. Both elastic energy loss and multiple scattering are known to obey scaling laws involving only two combinations of the pertinent variables and atomic parameters. The dependence on deflection angle and foil thickness of mean and peak energy loss obeys a simple combination of these scaling laws. Comments are made on potential errors due to uncertainties in the nuclear-stopping correction applied in the literature with specific reference to central papers in low-velocity stopping

  2. Reliability metrics extraction for power electronics converter stressed by thermal cycles

    DEFF Research Database (Denmark)

    Ma, Ke; Choi, Uimin; Blaabjerg, Frede

    2017-01-01

    Due to the continuous demands for highly reliable and cost-effective power conversion, the quantified reliability performances of the power electronics converter are becoming emerging needs. The existing reliability modelling approaches for the power electronics converter mainly focuses on the pr...... performance of power electronics system. The final predicted results showed good accuracy with much more reliability information compared to the existing approaches, and the quantified reliability correlation to the mission profiles of converter is mathematically established....

  3. Reliability of high power electron accelerators for radiation processing

    International Nuclear Information System (INIS)

    Zimek, Z.

    2011-01-01

    Accelerators applied for radiation processing are installed in industrial facilities where accelerator availability coefficient should be at the level of 95% to fulfill requirements according to industry standards. Usually the exploitation of electron accelerator reviles the number of short and few long lasting failures. Some technical shortages can be overcome by practical implementation the experience gained in accelerator technology development by different accelerator manufactures. The reliability/availability of high power accelerators for application in flue gas treatment process must be dramatically improved to meet industrial standards. Support of accelerator technology dedicated for environment protection should be provided by governmental and international institutions to overcome accelerator reliability/availability problem and high risk and low direct profit in this particular application. (author)

  4. Reliability of high power electron accelerators for radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Zimek, Z. [Department of Radiation Chemistry and Technology, Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2011-07-01

    Accelerators applied for radiation processing are installed in industrial facilities where accelerator availability coefficient should be at the level of 95% to fulfill requirements according to industry standards. Usually the exploitation of electron accelerator reviles the number of short and few long lasting failures. Some technical shortages can be overcome by practical implementation the experience gained in accelerator technology development by different accelerator manufactures. The reliability/availability of high power accelerators for application in flue gas treatment process must be dramatically improved to meet industrial standards. Support of accelerator technology dedicated for environment protection should be provided by governmental and international institutions to overcome accelerator reliability/availability problem and high risk and low direct profit in this particular application. (author)

  5. Synthesis on power electronics for large fuel cells: From power conditioning to potentiodynamic analysis technique

    International Nuclear Information System (INIS)

    De Bernardinis, Alexandre

    2014-01-01

    Highlights: • Active load for fuel cell managing electrical drive constraints: frequency and current ripple can be adjusted independently. • Multi-port resonant soft-switched topology for power management of a thirty kilowatt segmented PEM fuel cell. • Splitting current control strategy for power segmented PEM fuel cell in case of a segment is under fault. • Reversible Buck topology for large fuel cell with control of the fuel cell potential linked to current density nonlinearity. - Abstract: The work addressed in this paper deals with a synthesis on power electronic converters used for fuel cells. The knowledge gap concerns conceptually different electronic converter architectures for PEM (Proton Exchange Membrane) fuel cells able to perform three types of functionalities: The first one is the capacity of emulating an active load representative of electrical drive constraints. In that case, frequency and fuel cell current ripple can be set independently to investigate the dynamic behavior of the fuel cell. The second one is power conditioning applied to large high power and segmented fuel cell systems (“Large” represents several tens of cells and multi-kilowatt stacks), which is a non trivial consideration regarding the topological choices to be made for improving efficiency, compactness and ensure operation under faulty condition. A multi-port resonant isolated boost topology is analyzed enabling soft switching over a large operating range for a thirty kilowatt segmented fuel cell. A splitting current control strategy in case of a segment is under fault is proposed. Each considered converter topologies meet specific constraints regarding fuel cell stack design and power level. The third functionality is the ability for the power electronics to perform analysis and diagnosis techniques, like the cyclic voltammetry on large PEM fuel cell assemblies. The latter technique is an uncommon process for large fuel cell stacks since it is rather performed on

  6. Agutaynen Glottal Stop.

    Science.gov (United States)

    Quakenbush, J. Stephen

    A study investigated the phonemic and morphophonemic patterning of the glottal stop in Agutaynen, a Meso-Philippine language, and some comparison with two northern Philippine languages. Agutaynen glottal stop has as its sole origin a neutralization of contrast rule, the operation of which can be noted in three different linguistic environments.…

  7. Control systems for power electronics a practical guide

    CERN Document Server

    Patil, Mahesh

    2015-01-01

    The scope of the book covers most of the aspects as a primer on power electronics starting from a simple diode bridge to a DC-DC convertor using PWM control. The thyristor-bridge and the mechanism of designing a closed loop system are discussed in chapter one, two and three. The concepts are applied in the fourth chapter as a case study for buck converter which uses MOSFETs as switching devices and the closed loop system is elaborated in the fifth chapter. Chapter six is focused on the embedded system basics and the implementation of controls in the digital domain. Chapter seven is a case study of application of an embedded control system for a DC motor. With this book, the reader will find it easy to work on the practical control systems with microcontroller implementation. The core intent of this book is to help gain an accelerated learning path to practical control system engineering and transform control theory to an implementable control system through electronics. Illustrations are provided for most of...

  8. Thermoelectric power in ionic and electronic mixed conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kamata, Masahiro; Jin-nouchi, Kenji; Esaka, Takao [Tottori Univ. (Japan). Faculty of Engineering

    1996-08-01

    In order to study the thermoelectric property of the oxide ionic and electronic mixed conductor of 10 mol% CaO-doped CeO{sub 2} (CDC), a new type of thermocell was prepared, in which platinum electrodes were embedded in the tube-type sample to diminish the large temperature gradient over the electrodes due to the local heat radiation from heating furnace. Using this thermocell, reproducible data were obtained. The thermoelectric power measured in CDC under various oxygen atmospheres (Po{sub 2}) from 1.0 to about 10{sup -15} atm showed that the sign of Seebeck coefficients changed from minus to plus. This variation of Seebeck coefficients vs. Po{sub 2} was well interpreted by considering that (1) the thermoelectric power could be a driving force to make actual and electrochemical oxygen transfer in the mixed conductor and (2) the electrode processes had limiting rates due to slow oxygen diffusion (or oxygen gas exhaustion at the cathode and evolution at the anode). (author)

  9. System aspects of the ILC-electronics and power pulsing

    CERN Document Server

    Götlicher, P

    2007-01-01

    The requirements for the electronics of an experiment at the international linear collider (ILC) are driven by the bunch structure of the accelerator - short trains (1ms) with bunch to bunch lag of 0.3μs interrupted by long empty intervals (199ms) - and the precision physics. Based on developments of the CALICEcollaboration a system for high granular dense calorimetry is presented. The talk covers the system aspect: — of compact sensors as Si-diodes and multi-pixel Geiger mode photo sensors, — of the electromechanics with components embedded into the PCB’s, — of integrating the functionality needed nearby the sensor into low power ASIC’s, — of a DAQ-chain, in which each channel triggers on its own and the data selection is installed into PC’s and — of calibrating the calorimeter. With the high number of 100 million channels the power consumption and cooling have to be investigated carefully. Calculations demonstrate, that active cooling inside the calorimeters can be avoided. But essential fo...

  10. High-power electronics thermal management with intermittent multijet sprays

    International Nuclear Information System (INIS)

    Panão, Miguel R.O.; Correia, André M.; Moreira, António L.N.

    2012-01-01

    Thermal management plays a crucial role in the development of high-power electronics devices, e.g. in electric vehicles. The greatest energy demands occur during power peaks, implying dynamic thermal losses within the vehicle’s driving cycle. Therefore, the need for devising intelligent thermal management systems able to efficiently respond to these power peaks has become a technological challenge. Experiments have been performed with methanol in order to quantify the maximum heat flux removed by a multijet spray to keep the 4 cm 2 surface temperature stabilized and below the threshold of 125 °C. A multijet atomization strategy consists in producing a spray through the multiple and simultaneous impact of N j cylindrical jets. Moreover, the spray intermittency is expressed through the duty cycle (DC), which depends on the frequency and duration of injection. Results evidence that: i) a shorter time between consecutive injection cycles enables a better distribution of the mass flow rate, resulting in larger heat transfer coefficient values, as well as higher cooling efficiencies; ii) compared with continuous sprays, the analysis evidences that an intermittent spray allows benefiting more from phase-change convection. Moreover, the mass flux is mainly affecting heat transfer rather than differences induced in the spray structure by using different multijet configurations. - Highlights: ► Intermittent spray cooling (ISC) is advantageous for intelligent thermal management. ► Distributing the mass flow rate through ISC improves heat transfer. ► Multijet sprays with increasing number of jets have higher heat transfer rates. ► ISC with multijet sprays benefit more from phase-change than continuous sprays.

  11. Transitioning to Physics-of-Failure as a Reliability Driver in Power Electronics

    DEFF Research Database (Denmark)

    Wang, Huai; Liserre, Marco; Blaabjerg, Frede

    2014-01-01

    Power electronics has progressively gained important status in power generation, distribution and consumption. With more than 70% of electricity processed through power electronics, recent research endeavors to improve the reliability of power electronic systems to comply with more stringent...... constraints on cost, safety and availability in various applications. This paper serves to give an overview of the major aspects of reliability in power electronics and to address the future trends in this multidisciplinary research direction. The ongoing paradigm shift in reliability research is presented...... first. Then the three major aspects of power electronics reliability are discussed, respectively, which cover from physics-of-failure analysis of critical power elec-tronic components, state-of-the-art design for reliability process and robustness validation, and intelligent control and condition...

  12. The electrical, thermal and spatial integration of a converter in a power electronic module

    NARCIS (Netherlands)

    Gerber, M.B.

    2005-01-01

    This thesis is concerned with the design and implementation of a power electronic system (14/42V DC/DC converter) that is implemented in the automotive environment, specifically the engine compartment. The power electronic system must have a high power density while operating in a high temperature

  13. Gun power source for electron gun of 3 MeV DC accelerator

    International Nuclear Information System (INIS)

    Dewangan, S.; Sharma, D.K.; Nanu, K.

    2011-01-01

    In DC electron beam accelerator electron gun is situated at high voltage terminal which requires constant power irrespective of beam energy. Floating power source is required for gun. This paper describes the scheme of static gun power source derived from parallel coupled voltage multiplier column. (author)

  14. Dosimetric comparison of stopping power calibration with dual-energy CT and single-energy CT in proton therapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jiahua [Department of Physics, University of Adelaide, Adelaide, SA 5005 (Australia); Penfold, Scott N., E-mail: scott.penfold@adelaide.edu.au [Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia and Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 (Australia)

    2016-06-15

    Purpose: The accuracy of proton dose calculation is dependent on the ability to correctly characterize patient tissues with medical imaging. The most common method is to correlate computed tomography (CT) numbers obtained via single-energy CT (SECT) with proton stopping power ratio (SPR). CT numbers, however, cannot discriminate between a change in mass density and change in chemical composition of patient tissues. This limitation can have consequences on SPR calibration accuracy. Dual-energy CT (DECT) is receiving increasing interest as an alternative imaging modality for proton therapy treatment planning due to its ability to discriminate between changes in patient density and chemical composition. In the current work we use a phantom of known composition to demonstrate the dosimetric advantages of proton therapy treatment planning with DECT over SECT. Methods: A phantom of known composition was scanned with a clinical SECT radiotherapy CT-simulator. The phantom was rescanned at a lower X-ray tube potential to generate a complimentary DECT image set. A set of reference materials similar in composition to the phantom was used to perform a stoichiometric calibration of SECT CT number to proton SPRs. The same set of reference materials was used to perform a DECT stoichiometric calibration based on effective atomic number. The known composition of the phantom was used to assess the accuracy of SPR calibration with SECT and DECT. Intensity modulated proton therapy (IMPT) treatment plans were generated with the SECT and DECT image sets to assess the dosimetric effect of the imaging modality. Isodose difference maps and root mean square (RMS) error calculations were used to assess dose calculation accuracy. Results: SPR calculation accuracy was found to be superior, on average, with DECT relative to SECT. Maximum errors of 12.8% and 2.2% were found for SECT and DECT, respectively. Qualitative examination of dose difference maps clearly showed the dosimetric advantages

  15. Electronic energy loss of fast molecules in matter

    International Nuclear Information System (INIS)

    Steinbeck, J.

    1975-06-01

    In high velocity collisions of molecular ions the correlated motion influence of the ion cores on the electronic energy loss is investigated. The stopping power in first Born approximation for a random arrangement of target atoms can be formulated in terms of the inelastic electronic structure factor. In treating the target atoms in Hartree-Fock approximation each electron can be regarded as stopping the ion independent of all other electrons without restriction by the Pauli principle. A second equivalent formulation of the stopping power leads to the dielectric function of the target. The results are applied to the stopping of H 2 + -ions. For vanishing distance between the two protons the stopping power per particle is twice that for single proton collisions. For distances in the order of the Bohr radius the correlated stopping power may even be smaller than for uncorrelated protons. With increasing distances the correlation influence vanishes. The stopping of H 2 + -ions in C, Si and Ge is discussed using Clementi wave functions for the core electrons and a free electron approximation with Lindhard's dielectric function for the valence electrons. The comparison with the only experimental result available for H 2 + in C at 300 keV yields qualitative agreement. (orig.) [de

  16. Luminescent beam stop

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Diane; Morton, Simon A.

    2017-10-25

    This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

  17. Transformational electronics: a powerful way to revolutionize our information world

    Science.gov (United States)

    Rojas, Jhonathan P.; Torres Sevilla, Galo A.; Ghoneim, Mohamed T.; Hussain, Aftab M.; Ahmed, Sally M.; Nassar, Joanna M.; Bahabry, Rabab R.; Nour, Maha; Kutbee, Arwa T.; Byas, Ernesto; Al-Saif, Bidoor; Alamri, Amal M.; Hussain, Muhammad M.

    2014-06-01

    With the emergence of cloud computation, we are facing the rising waves of big data. It is our time to leverage such opportunity by increasing data usage both by man and machine. We need ultra-mobile computation with high data processing speed, ultra-large memory, energy efficiency and multi-functionality. Additionally, we have to deploy energy-efficient multi-functional 3D ICs for robust cyber-physical system establishment. To achieve such lofty goals we have to mimic human brain, which is inarguably the world's most powerful and energy efficient computer. Brain's cortex has folded architecture to increase surface area in an ultra-compact space to contain its neuron and synapses. Therefore, it is imperative to overcome two integration challenges: (i) finding out a low-cost 3D IC fabrication process and (ii) foldable substrates creation with ultra-large-scale-integration of high performance energy efficient electronics. Hence, we show a low-cost generic batch process based on trench-protect-peel-recycle to fabricate rigid and flexible 3D ICs as well as high performance flexible electronics. As of today we have made every single component to make a fully flexible computer including non-planar state-of-the-art FinFETs. Additionally we have demonstrated various solid-state memory, movable MEMS devices, energy harvesting and storage components. To show the versatility of our process, we have extended our process towards other inorganic semiconductor substrates such as silicon germanium and III-V materials. Finally, we report first ever fully flexible programmable silicon based microprocessor towards foldable brain computation and wirelessly programmable stretchable and flexible thermal patch for pain management for smart bionics.

  18. Transformational electronics: a powerful way to revolutionize our information world

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-06-04

    With the emergence of cloud computation, we are facing the rising waves of big data. It is our time to leverage such opportunity by increasing data usage both by man and machine. We need ultra-mobile computation with high data processing speed, ultra-large memory, energy efficiency and multi-functionality. Additionally, we have to deploy energy-efficient multi-functional 3D ICs for robust cyber-physical system establishment. To achieve such lofty goals we have to mimic human brain, which is inarguably the world’s most powerful and energy efficient computer. Brain’s cortex has folded architecture to increase surface area in an ultra-compact space to contain its neuron and synapses. Therefore, it is imperative to overcome two integration challenges: (i) finding out a low-cost 3D IC fabrication process and (ii) foldable substrates creation with ultra-large-scale-integration of high performance energy efficient electronics. Hence, we show a low-cost generic batch process based on trench-protect-peel-recycle to fabricate rigid and flexible 3D ICs as well as high performance flexible electronics. As of today we have made every single component to make a fully flexible computer including non-planar state-of-the-art FinFETs. Additionally we have demonstrated various solid-state memory, movable MEMS devices, energy harvesting and storage components. To show the versatility of our process, we have extended our process towards other inorganic semiconductor substrates such as silicon germanium and III-V materials. Finally, we report first ever fully flexible programmable silicon based microprocessor towards foldable brain computation and wirelessly programmable stretchable and flexible thermal patch for pain management for smart bionics. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  19. Design of power electronics for TVC and EMA systems

    Science.gov (United States)

    Nelms, R. Mark; Bell, J. Brett; Shepherd, Michael T.

    1994-11-01

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. A previous project performed by Auburn University examined the use of the resonant dc link (RDCL) inverter, pulse density modulation (PDM), and mos-controlled thyristors (MCT's) for speed control of a brushless dc motor. The speed of the brushless dc motor is proportional to the applied stator voltage. In a PDM system, the control system determines the number of resonant voltage pulses which must be applied to the stator to achieve a desired speed. The addition of a waveshaping circuit to the front end of a standard three-phase inverter yields a RDCL inverter; the resonant voltage pulses are produced through the action of this wave shaping circuit and the inverter. This project has focused on the implementation of a system which permits zero-voltage switching with the bus voltage clamped at the input voltage level. In the same manner as the RDCL inverter, the inverter selected for this implementation is a combination of waveshaping circuit and a standard three-phase inverter. In addition, this inverter allows a pulse-width modulated (PWM)-like control scheme instead of a PDM scheme. The operation of waveshaping circuit will be described through analysis and waveforms. Design relationships will also be presented.

  20. "Stop Diabetes Now!"

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Diabetes "Stop Diabetes Now!" Past Issues / Fall 2009 Table of Contents ... Tips for Seniors at Risk for Type 2 Diabetes Lifestyle changes that lead to weight loss—such ...