Note: This page contains sample records for the topic electromagnetics electron cooling from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Electron cooling  

NASA Astrophysics Data System (ADS)

The brief review of the most significant and interesting achievements in electron cooling method, which took place during last two years, is presented. The description of the electron cooling facilities-storage rings and traps being in operation or under development-is given. The applications of the electron cooling method are considered. The following modern fields of the method development are discussed: crystalline beam formation, expansion into middle and high energy electron cooling (the Fermilab Recycler Electron Cooler, the BNL cooler-recuperator, cooling with circulating electron beam, the GSI project), electron cooling in traps, antihydrogen generation, electron cooling of positrons (the LEPTA project).

Meshkov, I.; Sidorin, A.

2004-10-01

2

ElectronicsCooling  

NSDL National Science Digital Library

An important concern facing electronics designers is heat dissipation. Especially in laptop computers and server farms, overheating can be a major problem. ElectronicsCooling is a free, quarterly publication that provides "practical information to the reader that relates to cooling of today's electronics." Every article since the magazine's debut in 1995 can be viewed from this site. Common topics are packaging, thermal design, and technical data related to many types of electronics. Contributions to ElectronicsCooling are generally from industry and academia.

2002-01-01

3

Coherent electron cooling  

SciTech Connect

Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

Litvinenko,V.

2009-05-04

4

Limits on electron cooling  

NASA Astrophysics Data System (ADS)

A simple discussion of electron cooling theory, with emphasis on relativistic scaling relations, is given. This discusion is used to predict the behaviovr of electron cooled beams, subjected also to an internal target and to intrabeam scattering. Technical considerations relating to the alignment and the confinement of electron beams for cooling indicate that the longitudinal magnetic field will be abandoned in favour of focusing by discrete lenses at electron energies above about 1 MeV. The experiments on acceleration, transport, and collection of prototype electron beams made at Novosibirsk and Wisconsin are discussed. It is concluded that intermediate energy electron cooling is within the capability of present technology, and although its most important application may be for improving the luminosity of colliders, nuclear and particle physics applications requiring high energy, spatial, or time resolution also may benefit.

Reistad, D.; Ellison, T. J. P.

1991-04-01

5

ELECTRON COOLING FOR RHIC.  

SciTech Connect

We introduce plans for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This project has a number of new features as electron coolers go: It will cool 100 GeV/nucleon ions with 50 MeV electrons; it will be the first attempt to cool a collider at storage-energy; and it will be the first cooler to use a bunched beam and a linear accelerator as the electron source. The linac will be superconducting with energy recovery. The electron source will be based on a photocathode gun. The project is carried out by the Collider-Accelerator Department at BNL in collaboration with the Budker Institute of Nuclear Physics.

BEN-ZVI,I.; AHRENS,L.; BRENNAN,M.; HARRISON,M.; KEWISCH,J.; MACKAY,W.; PEGGS,S.; ROSER,T.; SATOGATA,T.; TRBOJEVIC,D.; YAKIMENKO,V.

2001-06-18

6

Computational electronics and electromagnetics  

SciTech Connect

The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domain CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.

Shang, C. C.

1997-02-01

7

Electron Cooling of RHIC  

SciTech Connect

We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV. A Zeroth Order Design Report is in an advanced draft state, and can be found on the web at http://www.agsrhichome.bnl.gov/eCool/.

I. Ben-Zvi; D.S. Barton; D.B. Beavis; M. Blaskiewicz; J.M. Brennan; A. Burrill; R. Calaga; P. Cameron; X.Y. Chang; R. Connolly; Yu.I. Eidelman; A.V. Fedotov; W. Fischer; D.M. Gassner; H. Hahn; M. Harrison; A. Hershcovitch; H.-C. Hseuh; A.K. Jain; P.D.J. Johnson; D. Kayran; J. Kewisch; R.F. Lambiase; V. Litvinenko; W.W. MacKay; G.J. Mahler; N. Malitsky; G.T. McIntyre; W. Meng; K.A.M. Mirabella; C. Montag; T.C.N. Nehring; T. Nicoletti; B. Oerter; G. Parzen; D. Pate; J. Rank; T. Rao; T. Roser; T. Russo; J. Scaduto; K. Smith; D. Trbojevic; G. Wang; J. Wei; N.W.W. Williams; K.-C. Wu; V. Yakimenko; A. Zaltsman; Y. Zhao; D.T. Abell; D.L. Bruhwiler; H. Bluem; A. Burger; M.D. Cole; A.J. Favale; D. Holmes; J. Rathke; T. Schultheiss; A.M.M. Todd; A.V. Burov; S. Nagaitsev; J.R. Delayen; Y.S. Derbenev; L. W. Funk; P. Kneisel; L. Merminga; H.L. Phillips; J.P. Preble; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; J.S. Sekutowicz

2005-05-16

8

ELECTRON COOLING FOR RHIC.  

SciTech Connect

The Accelerator Collider Department (CAD) at Brookhaven National Laboratory is operating the Relativistic Heavy Ion Collider (RHIC), which includes the dual-ring, 3.834 km circumference superconducting collider and the venerable AGS as the last part of the RHIC injection chain. CAD is planning on a luminosity upgrade of the machine under the designation RHIC II. One important component of the RHIC II upgrade is electron cooling of RHIC gold ion beams. For this purpose, BNL and the Budker Institute of Nuclear Physics in Novosibirsk entered into a collaboration aimed initially at the development of the electron cooling conceptual design, resolution of technical issues, and finally extend the collaboration towards the construction and commissioning of the cooler. Many of the results presented in this paper are derived from the Electron Cooling for RHIC Design Report [1], produced by the, BINP team within the framework of this collaboration. BNL is also collaborating with Fermi National Laboratory, Thomas Jefferson National Accelerator Facility and the University of Indiana on various aspects of electron cooling.

BEN-ZVI,I.

2001-05-13

9

Photonic and electronic cooling  

Microsoft Academic Search

Thermal management, which is usually regarded as the domain of mechanical engineering, actually offers exciting opportunities for photonics and electronics. This talk will describe research at Los Alamos National Laboratory and at the University of New Mexico on optical refrigeration and on thin-film electrocaloric heat engines. In optical refrigeration, the goal is to cool solids, typically rare-earth doped glasses and

Richard I. Epstein

2009-01-01

10

Electronic Component Cooling.  

National Technical Information Service (NTIS)

Cooling of electronic components on a circuit board is accomplished by a thermally conductive element such as a heat pipe that is in spaced parallel relation to the board and in contact with the upper surfaces of the components. The ends of the conductive...

K. H. Token

1980-01-01

11

Electromagnetic Trapping and Cooling of ^7Li  

NASA Astrophysics Data System (ADS)

Laser-cooling and atom trapping techniques have led to the realization of Bose-condensed alkalis, including ^7Li, which have increased our understanding of ultracold interactions and macroscopic coherence in matter. As a complement to our experiments with ^7Li, we are working to produce a degenerate gas of fermionic ^6Li with the goal of observing a BCS phase transition in a two-state mixture of ^6Li. In order to circumvent problems associated with evaporatively cooling a fermion, we will trap both isotopes in an electromagnetic trap and sympathetically cool the ^6Li with ^7Li. We are currently working on evaporatively cooling ^7Li, starting with N = 10^9 atoms and T = 700 ? K. These conditions should be sufficient to achieve run-away evaporation. Previous experiments with the (f,m_f) = (2,2) stretched state of ^7Li have shown that the negative triplet scattering length of -27 Bohr drastically limits the number of atoms obtained in the condensate. In contrast to these studies, we should be able to trap the (1,-1) state which scattering calculations have shown to have a positive scattering length of 5 Bohr. A ^7Li condensate in this state would be stable against density fluctuations and have no upper bound to condensate number. By driving atoms from this state back to the stretched state, a direct observation of mean-field induced collapse could be made. Our progress towards achieving these goals will be discussed.

McAlexander, W. I.; Strecker, K. E.; Truscott, A. G.; Hulet, R. G.

2000-06-01

12

Power electronics cooling apparatus  

DOEpatents

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.

Sanger, Philip Albert (Monroeville, PA); Lindberg, Frank A. (Baltimore, MD); Garcen, Walter (Glen Burnie, MD)

2000-01-01

13

Direct cooled power electronics substrate  

DOEpatents

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.

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

2010-09-14

14

Electron cooling experiments in CSR  

NASA Astrophysics Data System (ADS)

The six species heavy ion beam was accumulated with the help of electron cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). The ion beam accumulation dependence on the parameters of cooler was investigated experimentally. The 400 MeV/u 12C6+ and 200 MeV/u 129Xe54+ were stored and cooled in the experimental ring CSRe, and the cooling force was measured in different conditions.

Yang, XiaoDong; Li, Jie; Mao, LiJun; Li, GuoHong; Ma, XiaoMing; Yan, TaiLai; Mao, RuiShi; Yang, JianCheng; Yuan, YouJin; Parkhomchuk, Vasily; Reva, Vladimir

2011-12-01

15

Optimization of electron cooling in the Recycler  

SciTech Connect

Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1A DC electron beam (as well as by a stochastic cooling system). The paper describes electron cooling improvements recently implemented: adjustments of electron beam line quadrupoles to decrease the electron angles in the cooling section and better stabilization and control of the electron energy.

Shemyakin, A.; Burov, A.; Carlson, K.; Prost, L.R.; Sutherland, M.; Warner, A.; /Fermilab

2009-04-01

16

Cooling Technology for Electronic Computers  

NASA Astrophysics Data System (ADS)

The rapid growth of data processing speed in computers has been sustained by the advances in cooling technology. This article first presents a review of the published data of heat loads in recent Japanese large-scale computers. The survey indicates that, since around 1980, the high-level integration of microelectronic circuits has brought about almost four fold increase in the power dissipation from logic chips. The integration also has invited the evolutions of multichip modules and new schemes of electronic interconnections. Forced convection air-cooling and liquid cooling coupled with thermal connectors are discussed with reference to the designs employed in actual computers. More advanced cooling schemes are also discussed. Finally, the importance of thermal environmental control of computer rooms is emphasized.

Nakayama, Wataru

17

Coherent electron cooling demonstration experiment  

SciTech Connect

Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.

Litvinenko, V.N.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; Fedotov, A.; Hao, Y.; Kayran, D.; Mahler, G.; Marusic, A.; Meng, W.; McIntyre, G.; Minty, M.; Ptitsyn, V.; Pinayev, I.; Rao, T.; Roser, T.; Sheehy, B.; Tepikian, S.; Than, R.; Trbojevic, D.; Tuozzolo, J.; Wang, G.; Yakimenko, V.; Hutton, A.; Krafft, G.; Poelker, M.; Rimmer, R.; Bruhwiler, D.; Abell, D.T.; Nieter, C.; Ranjbar, V.; Schwartz, B.; Kholopov M.; Shevchenko, O.; McIntosh, P.; Wheelhouse, A.

2011-09-04

18

Electromagnetic Pumps for Main Cooling Systems of Commercialized Sodium-Cooled Fast Reactor  

Microsoft Academic Search

An electromagnetic pump (EMP) has superior potential to improve the economic performance and ease of maintenance of sodium-cooled fast reactors. This study investigates the adequateness of a modular-type EMP system for large-sized (1,500MWe class) sodium-cooled fast reactors. A flow rate of over 500 m\\/min is required for the main circulating pump of such reactors. There is concern that such a

Kosuke AIZAWA; Yoshitaka CHIKAZAWA; Shoji KOTAKE; Kuniaki ARA; Rie AIZAWA; Hiroyuki OTA

2011-01-01

19

VORPAL simulations relevant to coherent electron cooling  

SciTech Connect

Coherent electron cooling (CEC) [1] combines the best features of electron cooling and stochastic cooling, via free-electron laser technology [2], to offer the possibility of cooling high-energy hadron beams with order-of-magnitude shorter cooling times. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. VORPAL is the ideal code for simulating the modulator and kicker regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. Unlike previous VORPAL simulations [3] of electron cooling physics, where dynamical friction on the ions was the key metric, it is the details of the electron density wake driven by each ion in the modulator section that must be understood, followed by strong amplification in the FEL. We present some initial simulation results.

Bell,G.; Bruhwiler, D.; Sobol, A.; Ben-Zvi, I.; Litvinenko, V.; Derbenev, Y.

2008-06-23

20

Electromagnetic radiation field of an electron avalanche  

NASA Astrophysics Data System (ADS)

Electron avalanches are the main constituent of electrical discharges in the atmosphere. However, the electromagnetic radiation field generated by a single electron avalanche growing in different field configurations has not yet been evaluated in the literature. In this paper, the electromagnetic radiation fields created by electron avalanches were evaluated for electric fields in pointed, co-axial and spherical geometries. The results show that the radiation field has a duration of approximately 1-2 ns, with a rise time in the range of 0.25 ns. The wave-shape takes the form of an initial peak followed by an overshoot in the opposite direction. The electromagnetic spectrum generated by the avalanches has a peak around 109 Hz.

Cooray, Vernon; Cooray, Gerald

2012-11-01

21

Fermilab electron cooling project: Engineering aspects of cooling section  

SciTech Connect

The Fermilab Electron Cooling project involves interacting a 4.3 MeV, 0.5 A DC electron beam with 8.9 GeV/c antiprotons in the FNAL Recycler Ring. This interaction occurs through a 20-meter long cooling section consisting of 10 solenoid modules. This cooling process would lead to an increase in the Tevatron collider luminosity needed to support RunIIb parameters. There are several important engineering aspects of this cooling section including: solenoid design, vacuum system design, magnetic shielding, support system, and alignment methods. Details of the engineering issues related to each of these areas is discussed.

Jerry R. Leibfritz et al.

2001-07-25

22

Towards demonstration of electron cooling with bunched electron beam  

SciTech Connect

All electron cooling systems which were in operation so far employed electron beam generated with an electrostatic electron gun in DC operating mode, immersed in a longitudinal magnetic field. At low energies magnetic field is also being used to transport electron beam through the cooling section from the gun to the collector. At higher energies (few MeV), it was shown that one can have simpler electron beam transport without continuous magnetic field. Because of a rather weak magnetic field on the cathode and in the cooling section the latter approach was referred to as 'non-magnetized cooling', since there was no suppression of the transverse angular spread of the electron beam with the magnetic field in the cooling section. Such a cooler successfully operated at FNAL (2005-11) at electron beam energy of 4.3 MeV. Providing cooling at even higher energies would be easier with RF acceleration of electron beam, and thus using bunched electron beam for cooling. Significant efforts were devoted to explore various aspects of such bunched electron beam cooling as part of R and D of high-energy electron cooling for RHIC. However, experimental studies of such cooling are still lacking. Establishing this technique experimentally would be extremely useful for future high-energy applications. Presently there is an ongoing effort to build Proof-of-Principle (PoP) experiment of Coherent Electron Cooling (CEC) at RHIC, which promises to be superior to conventional electron cooling for high energies. Since the CEC experiment is based on bunched electron beam and it has sections where electron beam co-propagates with the ion beam at the same velocity, it also provides a unique opportunity to explore experimentally conventional electron cooling but for the first time with a bunched electron beam. As a result, it allows us to explore techniques needed for the high-energy electron cooling such as 'painting' with a short electron beam and control of ion beam distribution under cooling which is essential if cooling is provided in a collider. The software needed for comparison with the experiments is already developed as part of the previous high-energy electron cooling studies for RHIC. Since electron beam will be non-magnetized and there will be no magnetic field in the cooling section it will be also a first demonstration of fully non-magnetized cooling. The purpose of these studies was to explore whether we would be able to observe conventional electron cooling with parameters expected in the CEC PoP experiment. Below we summarize requirements on electron beam and cooling section needed for such demonstration.

Fedotov, A.

2012-01-11

23

Experimental demonstration of relativistic electron cooling  

SciTech Connect

We report on an experimental demonstration of electron cooling of high-energy antiprotons circulating in a storage ring. In our experiments, electron cooling, a well-established method at low energies (< 500 MeV/nucleon), was carried out in a new region of beam parameters, requiring a multi-MeV dc electron beam and an unusual beam transport line. In this letter we present the results of the longitudinal cooling force measurements and compare them with theoretical predictions.

Nagaitsev, S.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M.; Kazakevich, Grigory M.; Kroc, T.; Prost, L.; Pruss, S.; Sutherland, M.; Schmidt, C.W.; Seletskiy, S.; Shemyakin, A.; Tupikov, V.; Warner, A.; /Fermilab /Novosibirsk, IYF /Rochester U.

2005-11-01

24

Commissioning of electron cooling in CSRe  

NASA Astrophysics Data System (ADS)

The 400 MeV/u 12C6+ ion beam was successfully cooled by the intensive electron beam near 1 A in CSRe. The momentum cooling time was estimated near 15 s. The cooling force was measured in the cases of different electron beam profiles, and the different angles between the ion beam and electron beam. The lifetime of the ion beam in CSRe was over 80 h. The dispersion in the cooling section was confirmed as positive close to zero. The beam sizes before cooling and after cooling were measured by the moving screen. The beam diameter after cooling was about 1 mm. The bunch length was measured with the help of the signals from the beam position monitor. The diffusion was studied in the absence of the electron beam.

Yang, Xiao-Dong; Mao, Li-Jun; Li, Guo-Hong; Li, Jie; Ma, Xiao-Ming; Yan, Tai-Lai; Yuan, You-Jin; Song, Ming-Tao; Yang, Jian-Cheng; Liu, Yong; Zhao, Tie-Cheng; Xia, Jia-Wen; Zhang, Wei; Gao, Da-Qing; Zhou, Zhong-Zu; Yan, Hong-Bin; Mao, Rui-Shi; He, Yuan; Han, Shao-Fei; Zheng, Jian-Hua; Yang, Xiao-Tian; Zhao, Hong-Wei; Xiao, Guo-Qing; Yin, Da-Yu; Li, Peng; Jia, Huan; Parkhomchuk, Vasily; Reva, Vladimir; Skorobogatov, Dmitry

2010-07-01

25

Sympathetic Electromagnetically-Induced-Transparency Laser Cooling of Motional Modes in an Ion Chain  

NASA Astrophysics Data System (ADS)

We use electromagnetically-induced-transparency laser cooling to cool motional modes of a linear ion chain. As a demonstration, we apply electromagnetically-induced-transparency cooling on Mg+24 ions to cool the axial modes of a Be+9-Mg+24 ion pair and a Be+9-Mg+24-Mg+24-Be+9 ion chain, thereby sympathetically cooling the Be+9 ions. Compared to previous implementations of conventional Raman sideband cooling, we achieve approximately an order-of-magnitude reduction in the duration required to cool the modes to near the ground state and significant reduction in required laser intensity.

Lin, Y.; Gaebler, J. P.; Tan, T. R.; Bowler, R.; Jost, J. D.; Leibfried, D.; Wineland, D. J.

2013-04-01

26

Electron cooling of heavy ion beams  

NASA Astrophysics Data System (ADS)

An introduction to the concept of phase-space compression of heavy-ion beams by electron cooling is given. Emphasis is put on a simple rather than a rigorous theoretical treatment of the underlying ideas. Some practical aspects are discussed in connection with a presentation of the designed cooling device for the Experimental storage ring ESR project of the Gesell-schaft für Schwerionenforschung GSI, Darmstadt. The problems of cooling-electron capture are briefly addressed.

Liesen, D.

1987-10-01

27

Electron Cooling Experiments at the Himac Synchrotron  

NASA Astrophysics Data System (ADS)

Electron-cooling experiments have been being carried out at the HIMAC-synchrotron in order to provide high-quality and high-intensity beams for medical and other applications. In transverse-cooling experiments, the cooling time and the equilibrium emittance in both the horizontal and vertical directions were measured. An intrabeam-scattering effect was also measured. The beam intensity was increased by one order through the cool-stacking method. The beam bunch was compressed from around 400 to 40 ns by combining the cooling and a sawtooth-wave rf-field. At the relatively high intensity, longitudinal and transverse instabilities were observed due to a space-charge effect, because the electron cooling resulted in a high-density beam.

Noda, K.; Shibuya, S.; Muramatsu, M.; Honma, T.; Takada, E.; Yamada, S.; Furukawa, T.; Uchiyama, H.; Fukushima, T.; Izumiya, H.; Ogawa, H. Y.; Iwashima, T.; Nagafuchi, T.; Maeda, K.; Fadil, H.; Shirai, T.; Noda, A.

2002-12-01

28

Electron Cooling of Intense Ion Beam  

Microsoft Academic Search

Results of experimental studies of the electron cooling of a proton beam at COSY (Juelich, Germany) are presented. Intensity of the proton beam is limited by two general effects: particle loss directly after the injection and development of instability in a deep cooled ion beam. Results of the instability investigations performed at COSY during last years are presented in this

J. Dietrich; V. Kamerdjiev; Yu. Korotaev; R. Maier; I. Meshkov; D. Prasuhn; A. Sidorin; A. Smirnov; J. Stein; H. Stockhorst

2006-01-01

29

DETAILED STUDIES OF ELECTRON COOLING FRICTION FORCE.  

SciTech Connect

High-energy electron cooling for RHIC presents many unique features and challenges. An accurate estimate of the cooling times requires detailed simulation of the electron cooling process. The first step towards such calculations is to have an accurate description of the cooling force. Numerical simulations are being used to explore various features of the friction force which appear due to several effects, including the anisotropy of the electron distribution in velocity space and the effect of a strong solenoidal magnetic field. These aspects are being studied in detail using the VORFAL code, which explicitly resolves close binary collisions. Results are compared with available asymptotic and empirical formulas and also, using the BETACOOL code, with direct numerical integration of less approximate expressions over the specified electron distribution function.

FEDOTOV, A.V.; BRUHWILER, D.L.; ABELL, D.T.; SIDORIN, A.O.

2005-09-18

30

Capillary Assisted Thermosyphon For Shipboard Electronics Cooling.  

National Technical Information Service (NTIS)

Recent advances in capillary pumped loop technology were incorporated into the design of a vertical flat plate evaporator for cooling high power electronics aboard naval vessels. This investigation included the design, fabrication, and experimentation of ...

E. H. Larsen

2003-01-01

31

ELECTRON COOLING IN THE RECYCLER COOLER  

SciTech Connect

A 0.1-0.5 A, 4.3 MeV DC electron beam provides cooling of 8 GeV antiprotons in Fermilab's Recycler storage ring. The most detailed information about the cooling properties of the electron beam comes from drag rate measurements. We find that the measured drag rate can significantly differ from the cooling force experienced by a single antiproton because the area of effective cooling is significantly smaller than the physical size of the electron beam and is comparable with the size of the antiproton beam used as a probe. Modeling by the BETACOOL code supports the conclusion about a large radial gradient of transverse velocities in the presently used electron beam.

SHEMYAKIN,A.; PROST, L.R.; FEDOTOV, A.; SIDORIN, A.

2007-09-10

32

Simulation study of electron response amplification in coherent electron cooling  

SciTech Connect

In Coherent Electron Cooling (CEC), it is essential to study the amplification of electron response to a single ion in the FEL process, in order to proper align the electron beam and the ion beam in the kicker to maximize the cooling effect. In this paper, we use Genesis to simulate the amplified electron beam response of single ion in FEL amplification process, which acts as Green's function of the FEL amplifier.

Hao Y.; Litvinenko, V.N.

2012-05-20

33

Luminosity Potentials in Colliders with Electron Cooling  

SciTech Connect

Luminosity upgrades of colliders with hadron beams, existing or designed, tend to require decreasing of beam emittances and maintaining them using a suitable cooling technique. The breakthroughs of recent years: realization of beam energy recovery in superconducting linear accelerators, flat to round beam transformations, new beam transport concepts (discontinuous solenoid, circulator rings, hollow beams, dispersive cooling) ? have promoted the feasibility of efficient electron cooling of intense high energy hadron beams. Electron cooling, in cooperation with strong SRF field in storage rings, will allow one to obtain very short hadron bunches, as result of which the luminosity can be raised by making a low beta-star. Short bunches also would makecrab crossing feasible, that allows one to remove the parasitic beam-beam interactions and maximize the collision rate. Cooling also results in flatness of uncoupled beam equilibrium; this can be used to diminish the IBS impact on luminosity

Derbenev, Yaroslav

2003-05-01

34

EFFECTS OF ELECTROMAGNETIC FIELDS ON HUMAN BEINGS AND ELECTRONIC DEVICES  

Microsoft Academic Search

It is important to be able to quantify both the absorption of electromagnetic (EM) energy in the human body and on electronic devices and the resulting effects. In this study, the electromagnetic radiation from electronic devices on the human and electronic devices was investigated. The human head model was simulated. The results were compared with the results of the studies

S. ?EKER; G. APAYDIN

35

Electronics Cooling Fan Noise Prediction  

Microsoft Academic Search

Using the finite volume CFD software FLUENT, one fan was studied at a given flow rate (1.5m3\\/min) for three different operational rotating speeds : 2,000, 2,350 and 2,700 rpm. The turbulent air flow analysis predicts the acoustic behavior of the fan. The best fan operating window, i.e. the one giving the best ratio between noise emissions and cooling performance, can

Antoine Dozolme; Hossam Metwally; Thierry Marchal

2007-01-01

36

Power electronics substrate for direct substrate cooling  

DOEpatents

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.

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

37

Radiative cooling of relativistic electron beams.  

SciTech Connect

Radiative cooling is a natural and effective method of phase-space cooling for stored electron beams. In electron storage rings the average effects of synchrotron radiation from the bending magnets cause the beam emittances in all three degrees of freedom to damp towards equilibria, determined by the fluctuating nature of quantum emissions. In this paper, they show that the radiation damping in a focusing system is fundamentally different from that in a bending system. Quantum excitation to the transverse dimensions is absent in a straight, continuous focusing channel, and is exponentially suppressed in a focusing-dominated ring. Thus, the transverse normalized emittances in such systems can in principle be damped to the Compton wavelength of the electron, limited only by the Heisenberg Uncertainty Principle. In addition, they investigate methods of rapid damping such as radiative laser cooling. They propose a laser-electron storage ring (LESR) where the electron beam in a compact storage ring repetitively interacts with an intense laser pulse stored in an optical resonator. The laser-electron interaction gives rise to fast cooling of electron beams and can be used to overcome the space-charge effects encountered in a medium-energy circular machine. Applications to the designs of ultra-low-emittance damping rings and compact x-ray sources are also explored.

Huang, Z.

1999-04-14

38

IBS FOR ION DISTRIBUTION UNDER ELECTRON COOLING.  

SciTech Connect

Standard models of the intra-beam scattering (IBS) are based on the growth of the rms beam parameters for a Gaussian distribution. As a result of electron cooling, the core of beam distribution is cooled much faster than the tails, producing a denser core. In this paper, we compare various approaches to IBS treatment for such distribution. Its impact on the luminosity is also discussed.

FEDOTOV,A.V.; BEN-ZVI,I.; EIDELMAN, YU.; LITVINENKO, V.; PARZEN, G.

2005-05-16

39

Electron Cooling of Intense Ion Beam  

SciTech Connect

Results of experimental studies of the electron cooling of a proton beam at COSY (Juelich, Germany) are presented. Intensity of the proton beam is limited by two general effects: particle loss directly after the injection and development of instability in a deep cooled ion beam. Results of the instability investigations performed at COSY during last years are presented in this report in comparison with previous results from HIMAC (Chiba, Japan) CELSIUS (Uppsala, Sweden) and LEAR (CERN). Methods of the instability suppression, which allow increasing the cooled beam intensity, are described. This work is supported by RFBR grant no. 05-02-16320 and INTAS grant no. 03-54-5584.

Dietrich, J.; Kamerdjiev, V.; Maier, R.; Prasuhn, D.; Stein, J.; Stockhorst, H. [FZJ, Juelich (Germany); Korotaev, Yu.; Meshkov, I.; Sidorin, A.; Smirnov, A. [JINR, Dubna (Russian Federation)

2006-03-20

40

Cooling Electron Plasmas by Cyclotron-Cavity Resonance  

NASA Astrophysics Data System (ADS)

A robust technique for cooling trapped non-neutral plasmas is to allow leptons to thermalize to the temperature of the experimental environment through cyclotron emission. Storing these plasmas in a high-Q cavity can enhance or inhibit this cooling mechanism dependent on the cyclotron frequency, the electromagnetic mode structure in the cavity, and the profile of the trapped plasma. Also, thermalization rates may be limited as temperatures in the system approach the energy spacing between Landau levels- the quantum mechanical levels of transverse particle motion in the system. This is a regime possible in a cryogenic environment with high magnetic fields, such as typically used in Penning-Malmberg traps. Here, we report on the progress of the cold electron research experiment at UC Berkeley designed to measure these effects.

Povilus, Alex; Baquero-Ruiz, Marcelo; Chapman, Steve; Fajans, Joel

2012-10-01

41

Analytical studies of coherent electron cooling  

SciTech Connect

Under certain assumptions and simplifications, we studied a few physics processes of Coherent Electron Cooling using analytical approach. In the modulation process, the effect due to merging the ion beam with the electron beam is studied under single kick approximation. In the free electron laser (FEL) amplifier, we studied the amplification of the electron density modulation using 1D analytical approach. Both the electron charge density and the phase space density are derived in the frequency domain. The solutions are then transformed into the space domain through Fast Fourier Transformation (FFT).

Wang,G.; Blaskiewicz, M.; Litvinenko, V.N.

2009-05-04

42

Electronic Warfare - Electromagnetic Threat Analysis System, (EW-ETAS).  

National Technical Information Service (NTIS)

This effort was for the development of a system to assist FTD's analysts in their efforts to provide scientific and technical intelligence on Electronic Warfare and its threat. The system is called the Electronic Warfare - Electromagnetic Threat Analysis ...

J. A. Rummans

1980-01-01

43

FREE ELECTRON LASERS AND HIGH-ENERGY ELECTRON COOLING.  

SciTech Connect

Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation of such beams is too feeble to provide significant cooling: even in the Large Hadron Collider (LHC) with 7 TeV protons, the longitudinal damping time is about thirteen hours. Decrements of traditional electron cooling decrease rapidly as the high power of beam energy, and an effective electron cooling of protons or antiprotons at energies above 100 GeV seems unlikely. Traditional stochastic cooling still cannot catch up with the challenge of cooling high-intensity bunched proton beams--to be effective, its bandwidth must be increased by about two orders-of-magnitude. Two techniques offering the potential to cool high-energy hadron beams are optical stochastic cooling (OSC) and coherent electron cooling (CEC)--the latter is the focus of this paper. In the early 1980s, CEC was suggested as a possibility for using various instabilities in an electron beam to enhance its interaction with hadrons (i.e., cooling them). The capabilities of present-day accelerator technology, Energy Recovery Linacs (ERLs), and high-gain Free-Electron Lasers (FELs), finally caught up with the idea and provided the all necessary ingredients for realizing such a process. In this paper, we discuss the principles, and the main limitations of the CEC process based on a high-gain FEL driven by an ERL. We also present, and summarize in Table 1, some numerical examples of CEC for ions and protons in RHIC and the LHC.

LITVINENKO,V.N.

2007-08-31

44

Potential Refrigerants for Power Electronics Cooling  

SciTech Connect

In the past, automotive refrigerants have conventionally been used solely for the purpose of air conditioning. However, with the development of hybrid-electric vehicles and the incorporation of power electronics (PEs) into the automobile, automotive refrigerants are taking on a new role. Unfortunately, PEs have lifetimes and functionalities that are highly dependent on temperature and as a result thermal control plays an important role in the performance of PEs. Typically, PEs are placed in the engine compartment where the internal combustion engine (ICE) already produces substantial heat. Along with the ICE heat, the additional thermal energy produced by PEs themselves forces designers to use different cooling methods to prevent overheating. Generally, heat sinks and separate cooling loops are used to maintain the temperature. Disturbingly, the thermal control system can consume one third of the total volume and may weigh more than the PEs [1]. Hence, other avenues have been sought to cool PEs, including submerging PEs in automobile refrigerants to take advantage of two-phase cooling. The objective of this report is to explore the different automotive refrigerants presently available that could be used for PE cooling. Evaluation of the refrigerants will be done by comparing environmental effects and some thermo-physical properties important to two-phase cooling, specifically measuring the dielectric strengths of potential candidates. Results of this report will be used to assess the different candidates with good potential for future use in PE cooling.

Starke, M.R.

2005-10-24

45

Electromagnetic Turbulence Simulations with Kinetic Electrons  

NASA Astrophysics Data System (ADS)

Recently a new electromagnetic kinetic electron delta-f particle simulation model has been demonstrated to work well at large values of plasma beta times the ion-to-electron mass ratio [1,2]. The new simulation presented here uses a generalized split-weight scheme [3,4], where the adiabatic part is adjustable, along with a parallel canonical momentum formulation [5] and has been developed in three-dimensional toroidal flux-tube geometry. The model also includes electron-ion collisional effects and has been linearly benchmarked with continuum codes [6,7]. Electromagnetic simulations with kinetic electrons require a timestep approximately one-half that of electrostatic adiabatic electron simulations. Large box size simulations of 256 by 256 in units of ion gyroradius using a realistic mass ratios run well and detailed convergence studies have been done. Finite-beta reduction of energy transport, below the adiabatic electron level is observed for betas below the kinetic ballooning limit. For beta above the kinetic ballooning threshold fluxes are extremely high, and it is unlikely to be an experimentally relevant regime. Zonal flows with kinetic electrons are found to be turbulent with the spectrum peaking at zero and having a width in the frequency range of the driving turbulence. This is in contrast with adiabatic electron cases where the zonal flows are near stationary. We have shown that the linear behavior of the zonal flow is not significantly affected by kinetic electrons. Zonal fields [9] are found to be very weak consistent with theoretical predictions for betas below the kinetic ballooning limit. Detailed spectral and cross-correlation analysis of the turbulent spectra will be presented in the various limits. Acknowledgments: Thanks to A.M. Dimits, D. Shumaker, LLNL; V.K. Decyk, J.N. Leboeuf UCLA, work done using the Summit Framework and supported by the DOE SciDAC Plasma Microturbulence Project. [1] Y. Chen and S.E. Parker, to appear in J. Comput. Phys. (2003). [2] Y. Chen, S.E. Parker, B.I. Cohen, A.M. Dimits, W.M. Nevins, D. Shumaker, V.K. Decyk and J.N. Leboeuf, to appear in Nuc. Fusion (2003). [3] I. Manuilskiy and W.W. Lee, Phys. Plasmas 7 1381 (2000). [4] Y. Chen and S.E. Parker, Phys. Plasmas 8 2095 (2001) [5] T.S. Hahm, W.W. Lee and A. Brizard, Phys. Fluids 31 1940 (1988). [6] W. Dorland et. al, Proc. 18th Int. Conf. on Fusion Energy, IAEA, Sorrento, Italy, 2000; W. Dorland, F. Jenko, M. Kotschenreuther and B.N. Rogers, Phys. Rev. Lett. 85, 5336 (2000). [7] J. Candy and R. Waltz, to appear in J. Comput. Physics (2003). [8] A.V. Gruzinov and P.H. Diamond, Phys. Plasmas 3 1854 (1996), L. Chen, Z. Lin R.B. White and F. Zonca, Nuc. Fusion 41 747 (2001); P.N. Gudzar, R.G. Kleva, A. Das and P.K. Kaw, Phys. Plasmas 8 3907 (2001).

Parker, Scott E.

2003-10-01

46

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.  

Code of Federal Regulations, 2010 CFR

...Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation...Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the...

2010-10-01

47

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.  

Code of Federal Regulations, 2010 CFR

...Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation...Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the...

2009-10-01

48

Two-beam instability in electron cooling  

NASA Astrophysics Data System (ADS)

The drift motion of cooling electrons makes them able to respond to transverse perturbations of a cooled ion beam. This response may lead to dipole or quadrupole transverse instabilities at specific longitudinal wave numbers. While the dipole instabilities can be suppressed by a combination of the Landau damping, machine impedance, and the active damper, the quadrupole and higher order modes can lead to either emittance growth, or a lifetime degradation, or both. The growth rates of these instabilities are strongly determined by the machine x-y coupling. Thus, tuning out of the coupling resonance and/or reduction of the machine coupling can be an efficient remedy for these instabilities.

Burov, A.

2006-12-01

49

ELECTRON COOLING SIMULATION FOR ARBITRARY DISTRIBUTION OF ELECTRONS  

SciTech Connect

Typically, several approximations are being used in simulation of electron cooling process, for example, density distribution of electrons is calculated using an analytical expression and distribution in the velocity space is assumed to be Maxwellian in all degrees of freedom. However, in many applications, accurate description of the cooling process based on realistic distribution of electrons is very useful. This is especially true for a high-energy electron cooling system which requires bunched electron beam produced by an Energy Recovery Linac (Em). Such systems are proposed, for instance, for RHIC and electron - ion collider. To address unique features of the RHIC-I1 cooler, new algorithms were introduced in BETACOOL code which allow us to take into account local properties of electron distribution as well as calculate friction force for an arbitrary velocity distribution. Here, we describe these new numerical models. Results based on these numerical models are compared with typical approximations using electron distribution produced by simulations of electron bunch through ERL of RHIC-II cooler.

SIDORIN,A.; SMIRNOV, A.; FEDOTOV, A.; BEN-ZVI, I.; KAYRAN, D.

2007-09-10

50

Survey and Alignment of the Fermilab Electron Cooling System  

SciTech Connect

The goal of achieving the Tevatron luminosity of 3 x 10{sup 32} cm{sup -2}s{sup -1} requires Electron Cooling in the Recycler Ring to provide an increased flux of antiprotons. The Fermilab Electron Cooling system has been designed to assist accumulation of antiprotons for the Tevatron collider operations. The installation along with the survey and alignment of the Electron Cooling system in the Recycler Ring were completed in November 2004. The Electron Cooling system was fully commissioned in May 2005 and the first cooling of antiprotons was achieved in July 2005. This paper discusses the alignment methodology employed to survey and align the Electron Cooling system.

Oshinowo, Babatunde O'Sheg; Leibfritz, Jerry; /Fermilab

2006-09-01

51

Miniature loop heat pipes for electronics cooling  

Microsoft Academic Search

The paper is devoted to the development of miniature loop heat pipes (mLHPs) with a nominal capacity of 25–30 W and a heat-transfer distance up to 250 mm intended for cooling electronics components and CPU of mobile PC. It gives the results of investigating several prototypes of mLHPs incorporated into remote heat exchanger (RHE) systems in different conditions. It has

V. G. Pastukhov; Yu. F. Maidanik; C. V. Vershinin; M. A. Korukov

2003-01-01

52

Electromagnetic Pumps for Fast Reactors Primary Cooling Circuits.  

National Technical Information Service (NTIS)

The review of the electromagnetic pump development for the main loops of the powerful atomic energy stations with fast neutron reactors is presented. The calculation results of the cylindrical pump at the p essure of 9x10 exp 5 Pa nad Na consumption of 15...

A. M. Andreev E. A. Bezgachev B. G. Karasev I. R. Kirillov A. P. Ogorodnikov

1977-01-01

53

Theory of electron cooling using electron cooling as an intrabeam scattering process  

Microsoft Academic Search

Electron cooling that results when a bunch of electrons overlaps a bunch of ions , with both bunches moving at the same velocity, may be considered to be an intrabeam scattering process. The process is similar to the usual intrabeam scattering, where the ions scatter from each other and usually results in beam growth. An important difference is that in

George Parzen

2006-01-01

54

A Fluid-kinetic Hybrid Electron Model for Electromagnetic Simulations  

SciTech Connect

A fluid-kinetic hybrid electron model for electromagnetic simulations of finite-beta plasmas is developed based on an expansion of the electron response using the electron-ion mass ratio as a small parameter (Here beta is the ratio of plasma pressure to magnetic pressure.) The model accurately recovers low-frequency plasma dielectric responses and faithfully preserves nonlinear kinetic effects (e.g., phase space trapping). Maximum numerical efficiency is achieved by overcoming the electron Courant condition and suppressing high-frequency modes. This method is most useful for nonlinear kinetic (particle-in-cell or Vlasov) simulations of electromagnetic microturbulence and Alfvenic instabilities in magnetized plasmas.

Zhihong Lin; Liu Chen

2001-01-30

55

Electron cooling experiments at the ESR  

NASA Astrophysics Data System (ADS)

The properties of electron cooled beams of highly charged ions have been studied at the ESR. New experiments using a beam scraper to determine the transverse beam size provide the beam parameters in the intrabeam scattering dominated intensity regime, but also at very low intensity when the ion beam enters into an ultra-cold state. Extremely low values of longitudinal and transverse beam temperature on the order of meV were achieved for less than 1000 stored ions. An experiment with bunched ultra-cold beam showed a limit of the line density which agrees with the one observed for coasting beams. Cooling of decelerated ions at a minimum energy of 3MeV/u has been demonstrated recently.

Steck, M.; Beller, P.; Beckert, K.; Franzke, B.; Nolden, F.

2004-10-01

56

Thermal management of high power dissipation electronic packages: from air cooling to liquid cooling  

Microsoft Academic Search

Performance-driven electronic packaging demands for thermal solutions of high power dissipation such as enhanced air cooling or, alternatively, liquid cooling technologies. This paper reports the characterization of air-cooled vapor chamber heat sink (VCHS) and liquid cooled heat sinks (LCHS) for electronic packages with a targeted power dissipation of 140W. The test vehicle flip chip plastic BGA package (FC-PBGA) involves a

H. Y. Zhang; D. Pinjala; Poi-Siong Teo

2003-01-01

57

Shielding of Electronic Systems against Transient Electromagnetic Interferences  

NASA Astrophysics Data System (ADS)

In order to protect electronic systems against the effects of transient electromagnetic interferences, shields made of electrically conductive material can be used. The subject of this paper is an electrically conductive textile. When applying the shield, a reliable measure is needed in order to determine the effectiveness of the shield to protect against electromagnetic pulses. For this purpose, a time domain measurement technique is presented using double exponential pulses. With these pulses, the susceptibility of an operating electronic device with and without the shield is determined. As a criterion of quality of a shield, the breakdown failure rate found in both cases is compared.

Herlemann, H.; Korte, S.; Camp, M.; Garbe, H.; Koch, M.; Sabath, F.

2005-05-01

58

Microbunched Electron Cooling for High-Energy Hadron Beams  

NASA Astrophysics Data System (ADS)

Electron and stochastic cooling are proven methods for cooling low-energy hadron beams, but at present there is no way of cooling hadrons as they near the TeV scale. In the 1980s, Derbenev suggested that electron instabilities, such as free-electron lasers, could create collective space charge fields strong enough to correct the hadron energies. This Letter presents a variation on Derbenev’s electron cooling scheme using the microbunching instability as the amplifier. The large bandwidth of the instability allows for faster cooling of high-density beams. A simple analytical model illustrates the cooling mechanism, and simulations show cooling rates for realistic parameters of the Large Hadron Collider.

Ratner, D.

2013-08-01

59

Microbunched electron cooling for high-energy hadron beams.  

PubMed

Electron and stochastic cooling are proven methods for cooling low-energy hadron beams, but at present there is no way of cooling hadrons as they near the TeV scale. In the 1980s, Derbenev suggested that electron instabilities, such as free-electron lasers, could create collective space charge fields strong enough to correct the hadron energies. This Letter presents a variation on Derbenev's electron cooling scheme using the microbunching instability as the amplifier. The large bandwidth of the instability allows for faster cooling of high-density beams. A simple analytical model illustrates the cooling mechanism, and simulations show cooling rates for realistic parameters of the Large Hadron Collider. PMID:24010445

Ratner, D

2013-08-20

60

ELECTRON COOLING AND ELECTRON-ION COLLIDERS AT BNL.  

SciTech Connect

Superconducting Energy Recovery Linacs (ERL) have significant potential uses in various fields, including High Energy Physics and Nuclear Physics. Brookhaven National Laboratory (BNL) is pursuing some of the potential applications in this area and the technology issues that are associated with these applications. The work addressed in this paper is carried out at BNL towards applications in electron cooling of high-energy hadron beams and electron-nucleon colliders. The common issues for these applications are the generation of high currents of polarized or high-brightness unpolarized electrons, high-charge per bunch and high-current. One must address the associated issue of High-Order Modes generation and damping. Superconducting ERLs have great advantages for these applications as will be outlined in the text.

BEN-ZVI,I.

2007-10-03

61

Electromagnetic Interference Generated from Fast Switching Power Electronic Devices  

Microsoft Academic Search

This paper investigates the negative effects of electromagnetic interference (EMI) due to fast switching power devices (high dv\\/dt and di\\/dt) used in power electronic converters and industrial equipment. Mitigation techniques have been explored to reduce EMI noise effectively. Remedial measures to reduce the risk of equipment malfunction and health risk due to EMI have been explored. In this paper, EMI

K. M. Muttaqi; M. E. Haque

2008-01-01

62

A Highly Efficient Computational Model for FDTD Simulations of Ultrafast Electromagnetic Interactions With Semiconductor Media With Carrier Heating\\/Cooling Dynamics  

Microsoft Academic Search

We report a new computational model to incorporate carrier heating\\/cooling effects for the finite-difference time-domain (FDTD) simulation of electromagnetic interactions with semiconductor media. The model is formulated to be computationally efficient enough to be applied to FDTD simulations of photonic devices of complex structural geometry. The model developed here is built on top of a previous multi-level multi-electron (MLME) model

Koustuban Ravi; Yingyan Huang; Seng-Tiong Ho

2012-01-01

63

Electronics Cooling Using a Self-Contained, Sub-Cooled Pumped Liquid System  

Microsoft Academic Search

Electronic thermal packaging design continues to look for novel solutions for enhancing the performance of microelectronic cooling solutions. Driven by increasing thermal performance requirements, particularly in densely packaged militarized electronic systems and other high density or extreme use products, thermal designers are showing that to achieve the necessary cooling, combinations of existing technologies may offer further enhancement than has already

W. John Bilski; Gregg Baldassarre; Matt Connors; Jerry Toth; Kevin L. Wert

2008-01-01

64

Field measurements in the Fermilab electron cooling solenoid prototype  

SciTech Connect

To increase the Tevatron luminosity, Fermilab is developing a high-energy electron cooling system [1] to cool 8.9-GeV/c antiprotons in the Recycler ring. The schematic layout of the Recycler Electron Cooling (REC) system is shown in Figure 1. Cooling of antiprotons requires a round electron beam with a small angular spread propagating through a cooling section with a kinetic energy of 4.3 MeV. To confine the electron beam tightly and to keep its transverse angles below 10{sup -4} rad, the cooling section will be immersed into a solenoidal field of 50-150G. As part of the R&D effort, a cooling section prototype consisting of 9 modules (90% of the total length of a future section) was assembled and measured. This paper describes the technique of measuring and adjusting the magnetic field quality in the cooling section and presents preliminary results of solenoid prototype field measurements. The design of the cooling section solenoid is discussed in Chapter 2. Chapter 3 describes details of a dedicated measurement system, capable of measuring small transverse field components, while the system's measurement errors are analyzed in Chapter 4. Chapter 5 contains measured field distributions of individual elements of the cooling section as well as an evaluation of the magnetic shielding efficiency. An algorithm of field adjustments for providing lowest possible electron trajectory perturbations is proposed in Chapter 6; also, this chapter shows the results of our first attempts of implementing the algorithm.

A. C. Crawford et al.

2003-10-02

65

The integration of cryogenic cooling systems with superconducting electronic systems  

Microsoft Academic Search

The need for cryogenic cooling has been critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of the superconducting circuit is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a disadvantage. This report will talk about the various methods for refrigerating superconducting devices. Cryocooler types

Michael A

2003-01-01

66

THE ELECTRON GUN WITH VARIABLE BEAM PROFILE FOR OPTIMIZATION OF ELECTRON COOLING  

Microsoft Academic Search

Considerable losses of ions appear during an electron cooling of intensive ion beams. These are recombination losses and the losses arisen due to the instability development of the cooled beam. To avoid these effects the usage of hollow electron beams was proposed. The electron beam density in central part can be decreased at many times without reduction of the cooling

A. Bubley; A. Goncharov; A. Ivanov; E. Konstantinov; S. Konstantinov; A. Kryuchkov; V. Panasyuk; V. Parkhomchuk; V. Reva; B. Skarbo; B. Smirnov; B. Sukhina; M. Tiunov

67

Ground-state cooling for a trapped atom using cavity-induced double electromagnetically induced transparency.  

PubMed

We propose a cooling scheme for a trapped atom using the phenomenon of cavity-induced double electromagnetically induced transparency (EIT), where the atom comprising of four levels in tripod configuration is confined inside a high-finesse optical cavity. By exploiting one cavity-induced EIT, which involves one cavity photon and two laser photons, carrier transition can be eliminated due to the quantum destructive interference of excitation paths. Heating process originated from blue-sideband transition mediated by cavity field can also be prohibited due to the destructive quantum interference with the additional transition between the additional ground state and the excited state. As a consequence, the trapped atom can be cooled to the motional ground state in the leading order of the Lamb-Dicke parameters. In addition, the cooling rate is of the same order of magnitude as that obtained in the cavity-induced single EIT scheme. PMID:23481803

Yi, Zhen; Gu, Wen-ju; Li, Gao-xiang

2013-02-11

68

Progress with FEL-based coherent electron cooling  

SciTech Connect

Cooling intense high-energy hadron beams remains a major challenge for accelerator physics. Synchrotron radiation is too feeble, while efficiency of two other cooling methods falls rapidly either at high bunch intensities (i.e. stochastic cooling of protons) or at high energies (i.e. e-cooling). The possibility of coherent electron cooling, based on high-gain FEL and ERL, was presented at last FEL conference [1]. This scheme promises significant increases in luminosities of modern high-energy hadron and electron-hadron colliders, such as LHC and eRHIC. In this paper we report progress made in the past year on the development of this scheme of coherent electron cooling (CeC), results of analytical and numerical evaluation of the concept as well our prediction for LHC and RHIC. We also present layout for proof-of-principle experiment at RHIC using our R&D ERL which is under construction.

Litvinenko,V.; Ben-Zvi, I.; Blaskiewicz, M.; Hao, Y.; Kayran, D.; Pozdeyev, E.; Wang, G.; Bell, G.; Bruhwiler, D.; Sobol, A.; Shevchenko, O.; Vinokurov, N.A.; Derbenev, Y.; Reiche, S.

2008-08-24

69

PROGRESS OF HIGH-ENERGY ELECTRON COOLING FOR RHIC.  

SciTech Connect

The fundamental questions about QCD which can be directly answered at Relativistic Heavy Ion Collider (RHIC) call for large integrated luminosities. The major goal of RHIC-I1 upgrade is to achieve a 10 fold increase in luminosity of Au ions at the top energy of 100 GeV/nucleon. Such a boost in luminosity for RHIC-II is achievable with implementation of high-energy electron cooling. The design of the higher-energy cooler for RHIC-II recently adopted a non-magnetized approach which requires a low temperature electron beam. Such electron beams will be produced with a superconducting Energy Recovery Linac (ERL). Detailed simulations of the electron cooling process and numerical simulations of the electron beam transport including the cooling section were performed. An intensive R&D of various elements of the design is presently underway. Here, we summarize progress in these electron cooling efforts.

FEDOTOV,A.V.

2007-09-10

70

Kinetics of electron cooling of positrons in a storage ring  

SciTech Connect

Kinetic equations are derived for the positron velocity distribution in storage rings with electron cooling. Both drag force and components of the velocity diffusion tensor are calculated. The mechanism of approach to a steady-state positron velocity distribution via electron cooling is discussed. It is shown that the resulting steady-state positron distribution is very close to the electron distribution when the magnetic field is sufficiently strong.

Men'shikov, L. I. [Russian Research Centre Kurchatov Institute (Russian Federation)], E-mail: mleonid1954@mail.ru

2008-06-15

71

Electron cooling for low-energy RHIC program  

SciTech Connect

Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beam energies below 10 GeV/nucleon. Providing collisions at such energies, termed RHIC 'low-energy' operation, will help to answer one of the key questions in the field of QCD about existence and location of critical point on the QCD phase diagram. The electron cooling system should deliver electron beam of required good quality over energies of 0.9-5 MeV. Several approaches to provide such cooling were considered. The baseline approach was chosen and design work started. Here we describe the main features of the cooling system and its expected performance. We have started design work on a low-energy RHIC electron cooler which will operate with kinetic electron energy range 0.86-2.8 (4.9) MeV. Several approaches to an electron cooling system in this energy range are being investigated. At present, our preferred scheme is to transfer the Fermilab Pelletron to BNL after Tevatron shutdown, and to use it for DC non-magnetized cooling in RHIC. Such electron cooling system can significantly increase RHIC luminosities at low-energy operation.

Fedotov, A.; Ben-Zvi, I.; Chang, X.; Kayran, D.; Litvinenko, V.N.; Pendzick, A.; Satogata, T.

2009-08-31

72

Modeling and simulation of electromagnetic wave propagation in electronic packages  

Microsoft Academic Search

In this dissertation, some research involving signal integrity analysis in electronic packages and printed circuit boards is introduced. Emphasis is concentrated on the modeling, parameter extraction, and simulation techniques related to the electromagnetic wave propagation in multi-layered power and ground plane structures. One aspect of the research covers parameter extraction of multi-conductor multi-layered transmission lines. Suggestions are given for using

Danwei Xue

1997-01-01

73

Electronic calibration developed for the CMS electromagnetic calorimeter  

Microsoft Academic Search

An electronic system, designed to provide a relative calibration for the readout of the CMS electromagnetic calorimeter (CMS-ECAL), is described. On request, this system injects a pulse at the input of a predetermined group of preamplifiers with preselected amplitude and a shape identical to the one produced by the photodetectors. Several chips, in DMILL 0.8?m technology, have been developed for

Y. Baek; D. Boget; P. Y David; J. Ditta; V. Hermel; N. Fouque; J. P Mendiburu; P. Nedelec; J. P Peigneux; V. Poireau; P. Rebecchi; D. Sillou

2004-01-01

74

Atom-membrane cooling and entanglement using cavity electromagnetically induced transparency  

SciTech Connect

We investigate a hybrid optomechanical system composed of a micromechanical oscillator as a movable membrane and an atomic three-level ensemble within an optical cavity. We show that a suitably tailored cavity field response via electromagnetically induced transparency (EIT) in the atomic medium allows for strong coupling of the membrane's mechanical oscillations to the collective atomic ground-state spin. This facilitates ground-state cooling of the membrane motion, quantum state mapping, and robust atom-membrane entanglement even for cavity widths larger than the mechanical resonance frequency.

Genes, Claudiu; Ritsch, Helmut [Institute for Theoretical Physics, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Drewsen, Michael; Dantan, Aurelien [QUANTOP, Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2011-11-15

75

Radiative Laser Cooling in an Electron Storage Ring  

NASA Astrophysics Data System (ADS)

Radiative laser cooling is one way to reduce the horizontal emittance of an electron beam. When an electron collides head-on with a laser beam, the electron’s energy spread can be very large. In order to store an electron beam, it is desirable to reduce its energy spread. By changing the collision angle, we can decreace the horizontal emittance while reducing the energy spread. Radiative laser cooling is an efficient method to reduce the horizontal emittance which is increased by the intrabeam scattering.

Shobuda, Yoshihiro

2001-04-01

76

Electromagnetic Phenomena in Superconducting Magnet for Fusion Facility -Pool-Cooled Superconducting Coil-  

NASA Astrophysics Data System (ADS)

The features of superconducting coils for nuclear fusion devices include large size, high field, and high current density. A large conductor is needed for such a large coil to suppress the voltage increase. Since the ability of pool-cooling becomes relatively less with the increase of conductor size, new technologies are necessary to achieve both sufficient mechanical strength and cryogenic stability with high current density. A composite conductor of the 20 kA class was developed for the LHD helical coils. The conductor consists of a pure aluminum stabilizer, a copper sheath, and NbTi/Cu strands. New electromagnetic phenomena, which are Hall current and slow current diffusion into the stabilizer, deteriorate the cryogenic stability. The mechanism and countermeasures are described. Furthermore, a perspective on pool-cooled coils is discussed.

Imagawa, Shinsaku

77

Cooling structure for EMC shielded high frequency electronics  

Microsoft Academic Search

Cooling of electronics is normally achieved using air passing through apertures in the enclosure; as a result the shielding effectiveness of the shielded enclosure is reduced. In this paper, the design of a new cooling structure and its evaluation in a wind tunnel is presented. The developed design presented here is a double heat sink in extruded aluminum. Into one

W. Peter Siebert

2006-01-01

78

Progress on Analytical Modeling of Coherent Electron Cooling  

SciTech Connect

We report recent progresses on analytical studies of Coherent Electron Cooling. The phase space electron beam distribution obtained from the 1D FEL amplifier is applied to an infinite electron plasma model and the electron density evolution inside the kicker is derived. We also investigate the velocity modulation in the modulator and obtain a closed form solution for the current density evolution for infinite homogeneous electron plasma.

Wang, G.; Blaskiewicz, M.; Litvinenko, V.; Webb, S.

2010-05-23

79

Electromagnetic instability in an electron beam-ion channel system  

NASA Astrophysics Data System (ADS)

The transverse electromagnetic instability in the electron beam-ion channel system is investigated using kinetic theory. The equilibrium distribution function of a relativistic electron beam, which takes into account a strong ion channel effect, is obtained. The linearized Vlasov equation is solved and the dispersion relation of the system is derived by perturbing the equilibrium with a high frequency electromagnetic wave (EMW). Analysis of the dispersion relation shows that the coupling of the electron beam with the transverse high frequency EMW is achieved through the deflection of the beam electrons due to the synergistic effects of the transverse high frequency EMW and transverse betatron oscillation. The numerical calculation finds that a branch of slow wave instability (SWI) with a wide frequency band is excited. The attenuation index of the SWI increases and its frequency band broadens as the normalized beam radii increases. Besides, the SWI will be suppressed as the longitudinal velocity of the electron beam increases to a certain value; meanwhile, a bunch of fast wave instability (FWI) is excited, which is equal to the increase of the relativistic factor. Also both the SWI and the FWI reach maximum when the EMW frequency meets a resonance condition.

Su, D.; Tang, C. J.

2009-05-01

80

The integration of cryogenic cooling systems with superconducting electronic systems  

SciTech Connect

The need for cryogenic cooling has been critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of the superconducting circuit is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a disadvantage. This report will talk about the various methods for refrigerating superconducting devices. Cryocooler types will be compared for vibration, efficiency, and cost. Some solutions to specific problems of integrating cryocoolers to superconducting devices are presented.

Green, Michael A.

2003-07-01

81

HIGH-CURRENT ERL-BASED ELECTRON COOLING FOR RHIC.  

SciTech Connect

The design of an electron cooler must take into account both electron beam dynamics issues as well as the electron cooling physics. Research towards high-energy electron cooling of RHIC is in its 3rd year at Brookhaven National Laboratory. The luminosity upgrade of RHIC calls for electron cooling of various stored ion beams, such as 100 GeV/A gold ions at collision energies. The necessary electron energy of 54 MeV is clearly out of reach for DC accelerator system of any kind. The high energy also necessitates a bunched beam, with a high electron bunch charge, low emittance and small energy spread. The Collider-Accelerator Department adopted the Energy Recovery Linac (ERL) for generating the high-current, high-energy and high-quality electron beam. The RHIC electron cooler ERL will use four Superconducting RF (SRF) 5-cell cavities, designed to operate at ampere-class average currents with high bunch charges. The electron source will be a superconducting, 705.75 MHz laser-photocathode RF gun, followed up by a superconducting Energy Recovery Linac (ERL). An R&D ERL is under construction to demonstrate the ERL at the unprecedented average current of 0.5 amperes. Beam dynamics performance and luminosity enhancement are described for the case of magnetized and non-magnetized electron cooling of RHIC.

BEN-ZVI, I.

2005-09-18

82

Cavity Cooling of Ultracold Highly-Magnetized, One-Component Electron Plasmas  

NASA Astrophysics Data System (ADS)

In order to optimize the efficency of recombination processes, it is of interest, particularly for the antihydrogen trapping groups at CERN, to have large numbers (10^6 to 10^8) of ultracold (<=10 K) electrons and positrons available without the presence of a background buffer gas. To realize this, we utilize the fact that particles in a Penning-Malmberg style trap are typically confined in a 0.8T-3.0T homogeneous background magnetic field and thus can radiate away energy through cycltron motion. Choosing a high-Q trapping cavity with geometry such that electromagnetic cavity modes match the cyclotron frequency of the individual leptons, we can strongly couple the particles to the thermal bath of the cavity walls allowing for quick, passive cooling of the plasma. Here we present the model for this cooling mechanism and a description of the new electron plasma experiment that is being commissioned to study this effect.

Povilus, Alex; Chapman, Steven; Baquero-Ruiz, Marcelo; Fajans, Joel

2011-11-01

83

Cooling of hot electrons in amorphous silicon  

SciTech Connect

Measurements of the cooling rate of hot carriers in amorphous silicon are made with a two-pump, one-probe technique. The experiment is simulated with a rate-equation model describing the energy transfer between a population of hot carriers and the lattice. An energy transfer rate proportional to the temperature difference is found to be consistent with the experimental data while an energy transfer independent of the temperature difference is not. This contrasts with the situation in crystalline silicon. The measured cooling rates are sufficient to explain the difficulty in observing avalanche effects in amorphous silicon.

Vanderhaghen, R.; Hulin, D.; Cuzeau, S.; White, J.O.

1997-07-01

84

Feasibility of electron cooling and luminosity potentials of colliders  

SciTech Connect

Luminosity upgrades of colliders with hadron beams tend to require decreased and maintained beam emittances using a suitable cooling technique. The breakthroughs of recent years: realization of beam energy recovery in superconducting linear accelerators; flat to round beam transformations; and new beam transport concepts (discontinuous solenoid, circulator rings, hollow beams, dispersive cooling); have promoted the feasibility of efficient electron cooling of intense high energy hadron beams. Electron cooling, in cooperation with strong SRF fields in storage rings, will allow one to obtain very short hadron bunches, as result of which the luminosity can be raised by making a low beta-star. Short bunches also would make feasible crab crossing, that allows one to remove the parasitic beam-beam interactions and maximize the collision rate. Cooling also results in flatness of uncoupled beam equilibrium; this can be used to diminish the IBS impact on luminosity.

Yaroslav Derbenev

2004-07-02

85

Laser cooling of electron beams for linear colliders  

SciTech Connect

A novel method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10 J) one can decrease transverse beam emittances by a factor about 10 per one stage. The ultimate transverse emittances are much below that given by other methods. Depolarization of a beam during the cooling is about 5--15% for one stage. This method is especially useful for photon colliders and open new possibilities for e{sup +}e{sup {minus}} colliders and x-ray FEL based on high energy linacs.

Telnov, V.

1996-10-01

86

Coherent electron cooling proof of principle instrumentation design  

SciTech Connect

The goal of the Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to longitudinally cool a single bunch of 40 GeV/u gold ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.

Gassner D. M.; Litvinenko, V.; Michnoff, R.; Miller, T.; Minty, M.; Pinayev, I.

2012-04-15

87

An electrohydrodynamic polarization micropump for electronic cooling  

Microsoft Academic Search

This paper presents the design, fabrication, and characterization of an innovative microcooling device for microelectronics applications. The device incorporates an active evaporative cooling surface, a polarization micropump, and temperature sensors into a single chip. The micropump provides the required pumping action to bring the working fluid to the evaporating surface, allowing the effective heat transfer coefficient through a thin-film evaporation\\/boiling

J. Darabi; M. M. Ohadi; D. DeVoe

2001-01-01

88

On the possibilities of electron cooling for HERA  

NASA Astrophysics Data System (ADS)

It is under discussion to operate HERA with heavy ions instead of protons. Because of the heavily increased intrabeam scattering of heavy ions compared to protons, the achievable luminosity is much smaller than desired by the experiments. A way to increase luminosity could be electron cooling of the heavy ion beam. Because of the high electron energy of 180MeV necessary for cooling heavy ions in HERA the conventional approach using electrostatic DC sources is not possible. Instead an electron storage ring could be used. For this ring there are special requirements like small damping times, emittances and energy spread. The feasibility of such an electron storage ring has been studied, and the results with a possible solution are presented in this paper. Electron cooling of the HERA proton beam is also discussed briefly.

Gentner, M.; Brinkmann, R.; Derbenev, Y.; Husmann, D.; Steier, C.

1999-03-01

89

Modeling and simulation of electromagnetic wave propagation in electronic packages  

NASA Astrophysics Data System (ADS)

In this dissertation, some research involving signal integrity analysis in electronic packages and printed circuit boards is introduced. Emphasis is concentrated on the modeling, parameter extraction, and simulation techniques related to the electromagnetic wave propagation in multi-layered power and ground plane structures. One aspect of the research covers parameter extraction of multi-conductor multi-layered transmission lines. Suggestions are given for using empirical equations for simple structures. For complicated structures, available methods for parameter extraction are evaluated. The integral equation-Green's function method is used in the calculation of capacitance, inductance, resistance, and conductance matrices of the multi-conductor multi-layered transmission lines. Green's function can be used for parameter extraction of the transmission-line interconnects. The calculation of the Green's function in the multi-layered structure is presented by using the image pair extraction and Fourier series expansion method of the spectral domain Green's function developed in this dissertation. The method is found to be flexible, effective, accurate, robust, and fast. For the multi-layered power and ground plane structure, the effects of the conductor losses of metal planes and the split power and ground plane structures are modeled, and the parameters for the models are extracted by using the techniques developed in this dissertation. Another aspect of the work is the time domain simulation of the voltage fluctuation in the multi-layered power and ground plane structure in electronic packages and printed circuit boards. By investigating the behaviors of high order modes of the electromagnetic fields between the power and ground planes, it has been demonstrated that the parallel plate mode in the power and ground plane structure is the dominant electromagnetic field that can exist in the multi-layered power and ground plane structures. Based on this observation, a simple and fast scheme for the computation of the voltage waveform between two conducting planes is introduced. A technique is developed in the dissertation for the combination of the electronic circuit solver with the electromagnetic field solver in the time domain simulations of the lossy planes and the split plane structures. Finally, some special considerations are given to software development for electronic design automation.

Xue, Danwei

1997-06-01

90

Effects of e-beam parameters on coherent electron cooling  

SciTech Connect

Coherent Electron Cooling (CeC) requires detailed control of the phase between the hadron an the FEL-amplified wave packet. This phase depends on local electron beam parameters such as the energy spread and the peak current. In this paper, we examine the effects of local density variations on the cooling rates for CeC. Coherent Electron Cooling (CeC) [1] is a new concept in intense, high energy hadron beamcooling, in which the Debye screened charge perturbation calculated in [2] is used to seed a high-gain free electron laser (FEL). Using delays to give the perturbing hadron an energy-dependent longitudinal displacement relative to its frequencymodulated charge perturbation, the hadron receives an energy-dependent kick which reduces its energy variation from the design energy. The equations of motion in [1] assume that the electron bunch is the same physical size as the hadron bunch, and has a homogeneous charge density across the entire bunch. In practice, the electron bunches will be much shorter than the hadron bunch, and this local spacial inhomogeneity in the charge distribution will alter the gain length of the FEL, resulting in both a change in the amplification of the initial signal and a phase shift. In this paper we consider these inhomogeneity effects, determining cooling equations for bunched beam CeC consistent with these effects and determining thresholds for the cooling parameters.

Webb, S.D.; Litvinenko, V.N.; Wang, G.

2011-03-28

91

Flexible two-phase thermosyphon for power electronic cooling  

Microsoft Academic Search

A two phase thermosyphon system for power electronic cooling is presented. The designed evaporator can house multiple power electronics modules, it collects the generated vapor to a common flexible tube that drives the vapor to a plate heat exchanger condenser. The system was tested and simulated for a total power loss of 12.5 kW. The condenser was installed at a

Francesco Agostini; Bruno Agostini

2011-01-01

92

ELECTRON COOLING IN THE PRESENCE OF UNDULATOR FIELDS  

SciTech Connect

The design of the higher-energy cooler for Relativistic Heavy Ion Collider (RHIC) recently adopted a non-magnetized approach which requires a low temperature electron beam. However, to avoid significant loss of heavy ions due to recombination with electrons in the cooling section, the temperature of the electron beam should be high. These two contradictory requirements are satisfied in the design of the RWIC cooler with the help of the undulator fields. The model of the friction force in the presence of an undulator field was benchmarked vs. direct numerical simulations with an excellent agreement. Here, we discuss cooling dynamics simulations with a helical undulator, including recombination suppression and resulting luminosities.

FEDOTOV,A.; BEN-ZVI, I.; ET AL.

2007-06-25

93

First results of electron cooling experiments at LEAR  

Microsoft Academic Search

The first results are presented of electron cooling experiments in the Low-Energy Antiproton Ring (LEAR) at CERN, performed with a proton beam of about 50 and 21 MeV. The number of stored protons ranged from 107 to 3 × 109. Cooling times of the order 1 s and proton drag rates of up to 0.7 MeV\\/s were obtained. The capture

Helmut Poth; W. Schwab; B. Seligmann; M. Wörtge; A. Wolf; S A Baird; M. Chanel; H. Haseroth; C. E. Hill; R. Ley; Django Manglunki; G. Tranquille; J. L. Vallet; P. F. Dittner

1989-01-01

94

Compact liquid cooling system for small, moveable electronic equipment  

Microsoft Academic Search

A compact liquid cooling system has been evaluated in a benchmark of self-contained heat exchanger units that fit within small movable electronic equipment, such as PCs and workstations. The compact cooling system connects to a multichip module package via a pair of flexible stainless steel hoses. The system contains a fluid expansion chamber, a liquid-to-air heat exchanger core, a fan,

T. Y. Tom Lee; James Andrews; P. Chow; D. Saums

1992-01-01

95

ELECTRON HOLOGRAPHY OF ELECTROMAGNETIC FIELDS - RECENT THEORETICAL ADVANCES.  

SciTech Connect

It has been shown in this work that the Fourier space approach can be fruitfully applied to the calculation of the fields and the associated electron optical phase shift of several magnetic and electrostatic structures, like superconducting vortices in conventional and high-T{sub c} superconductors, reverse biased p-n junctions, magnetic domains and nanoparticles. In all these cases, this novel approach has led to unexpected but extremely interesting results, very often expressed in analytical form, which allow the quantitative and reliable interpretation of the experimental data collected by means of electron holography or of more conventional Lorentz microscopy techniques. Moreover, it is worth recalling that whenever long-range electromagnetic fields are involved, a physical model of the object under investigation is necessary in order to take into account correctly the perturbation of the reference wave induced by the tail of the field protruding into the vacuum. For these reasons, we believe that the Fourier space approach for phase computations we have introduced and discussed in this chapter will represent an invaluable tool for the investigation of electromagnetic fields at the meso- and nano-scale.

BELEGGIA,M.; POZZI, G.; TONOMURA, A.

2007-01-01

96

HIGH-ENERGY ELECTRON COOLING BASED ON REALISTIC SIX-DIMENSIONAL DISTRIBUTION OF ELECTRONS  

SciTech Connect

The high-energy electron cooling system for RHIC-II is unique compared to standard coolers. It requires bunched electron beam. Electron bunches are produced by an Energy Recovery Linac (ERL), and cooling is planned without longitudinal magnetic field. To address unique features of the RHIC cooler, a generalized treatment of cooling force was introduced in BETACOOE code which allows us to calculate friction force for an arbitrary distribution of electrons. Simulations for RHIC cooler based on electron distribution from ERL are presented.

FEDOTOV,A.; BEN-ZVI, I.; ET AL.

2007-06-25

97

Electronics for a highly segmented electromagnetic calorimeter prototype  

NASA Astrophysics Data System (ADS)

A prototype of a highly segmented electromagnetic calorimeter has been developed. The detector tower is made of 24 layers of PHASE2/MIMOSA23 silicon sensors sandwiched between tungsten plates, with 4 sensors per layer, a total of 96 MIMOSA sensors, resulting in 39 MPixels for the complete prototype detector tower. The paper focuses on the electronics of this calorimeter prototype. Two detector readout and control systems are used, each containing two Spartan 6 and one Virtex 6 FPGA, running embedded Linux, each system serving 12 detector layers. In 550 ms a total of 4 Gbytes of data is read from the detector, stored in memory on the electronics and then shipped to the DAQ system via Gigabit ethernet.

Fehlker, D.; Alme, J.; van den Brink, A.; de Haas, A. P.; Nooren, G.-J.; Reicher, M.; Röhrich, D.; Rossewij, M.; Ullaland, K.; Yang, S.

2013-03-01

98

Competition between electromagnetic modes in a free-electron maser  

NASA Astrophysics Data System (ADS)

A three part report is presented describing the mode competition in a gyrotron oscillator with two competing electromagnetic modes. Part 1 gives the theory of this mode coupling is presented using a quasi-linear assumption which is valid for small power levels. The results are interpreted in terms of the phase plane. These general results are applied to a specific case of mode competition, that between TE101 and TE011 modes in a cavity of rectangular cross section. Part 2 presents the theory of coupling which may occur between any number of cavity modes through finite conductivity in the cavity walls, holes in the conducting cavity walls, or though interaction with an electron beam. Part 3 details the experimental work. The electrodynamic circuit is described as are microwave and electron beam diagnostics. Results of initial tests are also given.

McCurdy, Alan H.; Kasibhotla, V.; Liou, R.; Plewa, J. S.

1994-02-01

99

ELECTRON COOLING SIMULATIONS FOR LOW-ENERGY RHIC OPERATION.  

SciTech Connect

Recently, a strong interest emerged in running the Relativistic Heavy Ion Collider (RHIC) at low beam total energies of 2.5-25 GeV/nucleon, substantially lower than the nominal beam total energy of 100 GeV/nucleon. Collisions in this low energy range are motivated by one of the key questions of quantum chromodynamics (QCD) about the existence and location of critical point on the QCD phase diagram. Applying electron cooling directly at these low energies in RHIC would result in significant luminosity increase and long beam stores for physics. Without direct cooling in RHIC at these low energies, beam lifetime and store times are very short, limited by strong transverse and longitudinal intrabeam scattering (IBS). In addition, for the lowest energies of the proposed energy scan, the longitudinal emittance of ions injected from the AGS into RHIC may be too big to fit into the RHIC RF bucket. An improvement in the longitudinal emittance of the ion beam can be provided by an electron cooling system at the AGS injection energy. Simulations of electron cooling both for direct cooling at low energies in RHIC and for injection energy cooling in the AGS were performed and are summarized in this report.

FEDOTOV,A.V.; BEN-ZVI, I.; CHANG, X.; KAYRAN, D.; SATOGATA, T.

2007-09-10

100

Optimization of electron cooling by SIN tunnel junctions  

NASA Astrophysics Data System (ADS)

We report on the optimization of electron cooling by SIN tunnel junctions due to the advanced geometry of superconducting electrodes and very effective normal metal traps for more efficient removal of quasiparticles at temperatures from 25 to 500 mK. The maximum decrease in electron temperature of about 200 mK has been observed at bath temperatures 300-350 mK. We used four-junction geometry with Al-AlOx-Cr/Cu tunnel junctions and Au traps. Efficient electron cooling was realized due to the improved geometry of the cooling tunnel junctions (quadrant shape of the superconducting electrode) and optimized Au traps just near the junctions ({\\approx }0.5~\\micmu {\\mathrm {m}} ) to reduce reabsorption of quasiparticles after removing them from normal metal. The maximum cooling effect was increased from a temperature drop of d T = -56 mK (ordinary cross geometry) to -130 mK (improved geometry of superconducting electrodes) and to d T = -200 mK (improved geometry of superconducting electrodes and effective Au traps). The heating peak (instead of cooling) near the zero voltage across cooling junctions has been observed in practice for all samples at temperatures below 150 mK. For higher cooling voltages close to the superconducting gap, the heating was converted to cooling with decreased amplitude. The leakage resistance of the tunnel junctions gives a reasonable explanation of the heating peak. The phonon reabsorption due to the recombination of quasiparticles in superconducting electrodes gives an additional improvement in the theoretical fitting but could not explain the heating peak. An anomalous zero-bias resistance peak has been observed for all tested structures. The peak is explained by Coulomb blockade of tunnelling in transistor-type structures with relatively small tunnel junctions. The work on electron cooling is devoted to the development of a cold-electron bolometer (CEB) with capacitive coupling by SIN tunnel junctions to the antenna for sensitive detection in the terahertz region. Direct electron cooling of an absorber plays a crucial role in supersensitive detection in the presence of a realistic background power load.

Kuzmin, L.; Agulo, I.; Fominsky, M.; Savin, A.; Tarasov, M.

2004-05-01

101

Laser Cooling of Electron Beams for Linear Colliders  

SciTech Connect

A novel method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with a focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10J) one can decrease transverse beam emittances by a factor of about 10 per stage. The ultimate transverse emittances are much below those achievable by other methods. Beam depolarization during cooling is about 5{percent}{endash}15{percent} for one stage. This method is especially useful for photon colliders and opens new possibilities for e{sup +}e{sup -} colliders and x-ray free-electron lasers based on high-energy linacs. {copyright} {ital 1997} {ital The American Physical Society}

Telnov, V. [Institute of Nuclear Physics, 630090 Novosibirsk (Russia)

1997-06-01

102

Resonant Compton Cooling and Emission by Relativistic Electrons in Magnetars  

NASA Astrophysics Data System (ADS)

For inner magnetospheric models of hard X-ray and gamma-ray emission in high-field pulsars and magnetars, resonant Compton upscattering is anticipated to be the most efficient process for generating continuum radiation. For magnetars, this is due in part to the proximity of a hot soft photon bath from the stellar surface. Moreover, because the scattering process becomes resonant at the cyclotron frequency, the effective cross section exceeds the classical Thomson value by over two orders of magnitude, thereby enhancing the efficiency of continuum production and the cooling of relativistic electrons. This paper presents computations of the electron cooling rates for this process, extending previous calculations of magnetic Thomson cooling to the domain of relativistic quantum effects, sampled near and above the quantum critical magnetic field of 44.13 TeraGauss. Angle-dependent hard X-ray spectra, incorporating self-consistent electon cooling via kinetic equation and Monte Carlo analyses, are also presented; these assume a radiation-reaction limited acceleration scenario for relativistic electrons in a magnetar magnetosphere. Our research addresses fully relativistic, quantum magnetic Compton cooling and emission by electrons, employing a new Sokolov and Ternov (ST) formulation of Compton scattering in strong magnetic fields. Such ST formalism is formally correct for treating spin-dependent effects that are important in the cyclotron resonance, and has not been addressed before in the context of Compton upscattering models of magnetar hard X-ray tail emission.

Wadiasingh, Zorawar; Baring, M. G.; Gonthier, P. L.; Harding, A. K.

2011-09-01

103

Cooling of Electronics with Phase Change Materials  

NASA Astrophysics Data System (ADS)

This paper deals with phase change materials (PCMs), used in conjunction with thermal conductivity enhancer (TCE), as means of thermal management of electronic systems. This work was motivated by the need for short term thermal management of high packing density equipments (such as in avionics). Eicosane is used as PCM, while aluminium pin or plate fins are used as TCE. The test section considered in all cases is 42×42 mm square base with TCE height of 25 mm. An electronic heater producing 4, 6 and 8 W was used to simulate the heat generation of electronic chips. Various volumetric percentages of TCE in the conglomerate of PCM and TCE were considered, namely, 0, 2, 8, 18 and 27%. The case with 8% volumetric percentage of TCE was found to have the best thermal performance. A numerical model was developed to enable interpretation of experimental results and to perform parametric studies.

Saha, S. K.; Dutta, P.

2010-10-01

104

Search for electron EDM with laser cooled radioactive atom  

NASA Astrophysics Data System (ADS)

The permanent electric dipole moment (EDM) of the elementary particle has the sensitivity to the CP violation in the theories beyond the standard model (SM). The search for the EDM constitutes the stringent test to discriminate between the SM and beyond it. We plan to perform the electron EDM search by using the laser cooled francium (Fr) atom which has the largest enhancement factor of the electron EDM in the alkali atoms. In this paper, the present status of the laser cooled Fr factory that is being constructed at Cyclotron and Radioisotope Center (CYRIC), Tohoku University are reported.

Inoue, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, T.; Kawamura, H.; Nataraj, H. S.; Sato, T.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.

2013-05-01

105

Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks  

NASA Astrophysics Data System (ADS)

We present waveform observations of electromagnetic lower hybrid and whistler waves with fci ? f < fce downstream of four supercritical interplanetary shocks using the Wind search coil magnetometer. The whistler waves were observed to have a weak positive correlation between ?B and normalized heat flux magnitude and an inverse correlation with Teh/Tec. All were observed simultaneous with electron distributions satisfying the whistler heat flux instability threshold and most with T? h/T? h > 1.01. Thus, the whistler mode waves appear to be driven by a heat flux instability and cause perpendicular heating of the halo electrons. The lower hybrid waves show a much weaker correlation between ?B and normalized heat flux magnitude and are often observed near magnetic field gradients. A third type of event shows fluctuations consistent with a mixture of both lower hybrid and whistler mode waves. These results suggest that whistler waves may indeed be regulating the electron heat flux and the halo temperature anisotropy, which is important for theories and simulations of electron distribution evolution from the Sun to the Earth.

Wilson, L. B.; Koval, A.; Szabo, A.; Breneman, A.; Cattell, C. A.; Goetz, K.; Kellogg, P. J.; Kersten, K.; Kasper, J. C.; Maruca, B. A.; Pulupa, M.

2013-01-01

106

Planar electromagnet microwiggler for free-electron lasers  

SciTech Connect

An electromagnet planar microwiggler for use in free electron lasers was tested, constructed of current conductors wound on ferromagnetic cores. A prototype with a period of 1 cm and gap of 0.5 cm produced a peak field on axis in excess of 4.6 kG, with a linear B/H characteristics to about 3.2 kG. The field of each half-period of the wiggler is independently tunable by adjusting the current delivered to each, thus allowing for precision tuning and/or wiggler tapering. General scaling laws to predict the performance of a geometrically similar design with a period of 5 mm were employed.

Stoner, R.; Chen, S.C.; Bekefi, G.

1990-06-01

107

Evolution of cooling technology for electrical, electronic, and microelectronic equipment  

Microsoft Academic Search

Selected aspects of cooling technology for electrical apparatus and electronic devices are considered for the past 80 years. The emphasis is on the past 50 years. The technology has evolved to meet the challenges of microminiaturization, and heat transfer considerations are now an integral part of the design procedure for microelectronic systems.

Arthur E. Bergles

2003-01-01

108

RESISTIVE BEHAVIOUR OF NB DIFUSSION-COOLED HOT ELECTRON BOLOMETERS  

Microsoft Academic Search

We present a new model for the description of the resistive transition of Nb diffusion-cooled hot electron bolometer mixers. The device is a thin (12 am) microbrid g e with a length and width of 220 nm, attached to large Au banks. Heterodyne mixing experiments in a 700 GHz waveguide receiver yield a receiver noise temperature (DSB) of 2200 K

D. Wilms Floet; J. R. Gao; T. M. Klapwijka

109

A uniform temperature heat sink for cooling of electronic devices  

Microsoft Academic Search

Experimental investigation of a heat sink for cooling of electronic devices is performed. The objective is to keep the operating temperature at a relatively low level of about 323–333 K, using a dielectric liquid that boils at a lower temperature, while reducing the undesired temperature variation in the both streamwise and transverse directions. The experimental study is based on systematic

G. Hetsroni; A. Mosyak; Z. Segal; G. Ziskind

2002-01-01

110

Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding  

SciTech Connect

Chaotic behavior of an electron motion in combined backward propagating electromagnetic wiggler and ion-channel electrostatic fields is studied. The Poincare surface-of-sections are employed to investigate chaotic behavior of electron motion. It is shown that the electron motion can exhibit chaotic behavior when the ion-channel density is low or medium, while for sufficiently high ion-channel density, the electron motion becomes regular (nonchaotic). Also, the chaotic trajectories decrease when the effects of self-fields of electron beam are taken into account and under Budker condition all trajectories become regular. The above result is in contrast with magnetostatic helical wiggler with axial magnetic field in which chaotic motion is produced by self-fields of electron beam. The chaotic and nonchaotic electron trajectories are confirmed by calculating Liapunov exponents.

Taghavi, Amin; Esmaeilzadeh, Mahdi; Fallah, Mohammad S. [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of)

2010-09-15

111

Electromagnetic effects of neutrinos in an electron gas  

NASA Astrophysics Data System (ADS)

We study the electromagnetic properties of a system that consists of an electron background and a neutrino gas that may be moving or at rest, as a whole, relative to the background. The photon self-energy for this system is characterized by the usual transverse and longitudinal polarization functions, and two additional ones which are the focus of our calculations, that give rise to birefringence and anisotropic effects in the photon dispersion relations. Expressions for them are obtained, which depend on the neutrino number densities and involve momentum integrals over the electron distribution functions, and are valid for any value of the photon momentum and general conditions of the electron gas. Those expressions are evaluated explicitly for several special cases and approximations which are generally useful in astrophysical and cosmological settings. Besides studying the photon dispersion relations, we consider the macroscopic electrodynamic equations for this system, which involve the standard dielectric and permeability constants plus two additional ones related to the photon self-energy functions. As an illustration, the equations are used to discuss the evolution of a magnetic field perturbation in such a medium. This particular phenomena has also been considered in a recent work by Semikoz and Sokoloff as a mechanism for the generation of large-scale magnetic fields in the early Universe as a consequence of the neutrino-plasma interactions, and allows us to establish contact with a specific application in a well defined context, with a broader scope and from a very different point of view.

Nieves, José F.; Sahu, Sarira

2005-04-01

112

Progress on a cryogenically cooled RF gun polarized electron source  

SciTech Connect

RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.

Fliller, R.P., III; Edwards, H.; /Fermilab

2006-08-01

113

Two-Phase Cooling Method Using R134a Refrigerant to Cool Power Electronic Devices  

SciTech Connect

This paper presents a two-phase cooling method using R134a refrigerant to dissipate the heat energy (loss) generated by power electronics (PE) such as those associated with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles (HEVs). The cooling method involves submerging PE devices in an R134a bath, which limits the junction temperature of PE devices while conserving weight and volume of the heat sink without sacrificing equipment reliability. First, experimental tests that included an extended soak for more than 300 days were performed on a submerged IGBT and gate-controller card to study dielectric characteristics, deterioration effects, and heat flux capability of R134a. Results from these tests illustrate that R134a has high dielectric characteristics, no deterioration on electrical components, and a heat flux of 114 W/cm 2 for the experimental configuration. Second, experimental tests that included simultaneous operation with a mock automotive air-conditioner (A/C) system were performed on the same IGBT and gate controller card. Data extrapolation from these tests determined that a typical automotive A/C system has more than sufficient cooling capacity to cool a typical 30 kW traction inverter. Last, a discussion and simulation of active cooling of the IGBT junction layer with R134a refrigerant is given. This technique will drastically increase the forward current ratings and reliability of the PE device

Lowe, Kirk T [ORNL; Tolbert, Leon M [ORNL; Ayers, Curtis William [ORNL; Ozpineci, Burak [ORNL; Campbell, Jeremy B [ORNL

2007-01-01

114

Electromagnets  

NSDL National Science Digital Library

In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often

Horton, Michael

2009-05-30

115

Principles of gyrotron powered electromagnetic wigglers for free-electron lasers  

Microsoft Academic Search

The operation of free-electron lasers (FEL's) with axial electron beams and high-power electromagnetic wiggler fields such as those produced by high-power gyrotrons is discussed. The use of short wavelength electromagnetic wigglers in waveguides and resonant cavities can significantly reduce required electron beam voltages, resulting in compact FEL's. Gain calculations in the low- and high-gain Compton regime are presented, including the

B. G. Danly; G. Bekefi; R. C. Davidson; R. J. Temkin; T. M. Tran

1987-01-01

116

A Project for synchrotron with electron cooling for cancer therapy  

NASA Astrophysics Data System (ADS)

A project for a new generation of proton and ion accelerator facilities for cancer therapy has been developed at the Budker Institute of Nuclear Physics (BINP), Siberian Branch, Russian Academy of Sciences (SB RAS). This facility includes an electrostatic injector, a booster with a 10-Hz repetition rate, and a main synchrotron with electron cooling and beam transport lines for delivering the beam to treatment rooms. The application of electron cooling makes it possible to increase the beam intensity and reduce the apertures of both the synchrotron and the high-energy transport lines, as well as save construction costs and energy consumption as required by the accelerator complex. This paper describes the main features of the synchrotron and the requirements for its main systems and their parameters.

Vostrikov, V. A.; Kiselev, V. A.; Levichev, E. B.; Parkhomchuk, V. V.; Reva, V. B.; Sinyatkin, S.

2012-07-01

117

Electronic spectroscopy of jet-cooled vinyl radical  

Microsoft Academic Search

The spectra of the X~2A'-A~2A'' electronic transition of jet-cooled vinyl radical, C2H3, and its partially deuterated isotopomer, CD2CH, have been obtained via action spectroscopy. The appearance of the H or D fragment was monitored via 1+1' resonance enhanced multiphoton ionization through the Lyman-alpha transition. The vibrational structure of the A~2A'' state was fully resolved and analyzed. The experimental vibrational frequencies

Michael B. Pushkarsky; Aaron M. Mann; Jake S. Yeston; C. Bradley Moore

2001-01-01

118

Two-phase flow instability analysis for transient electronics cooling  

Microsoft Academic Search

Because of increasing power densities, refrigeration systems are being explored for two-phase cooling of ultra high power electronic components. This paper presents a framework for the transient analysis of pressure-drop refrigerant flow instabilities under both steady-state and transient imposed heat loads. Based on an analytical two-phase flow model, the system pressure and other effects on flow characteristics are quantitatively studied,

TieJun Zhang; Yoav Peles; John T. Wen; Michael K. Jensen

2010-01-01

119

Compact liquid cooling system for small, moveable electronic equipment  

Microsoft Academic Search

The evaluation of a compact liquid cooling system is provided as a benchmark of self-contained heat exchanger units that can be used in small movable electronic equipment. The sealed system contains a fluid expansion chamber, a liquid-to-air heat exchanger core, a fan, and a pump that connects to a multichip module (MCM) package through a pair of flexible stainless steel

T. Y. Tom Lee; James A. Andrews; Peter Chow; David Saums

1992-01-01

120

Electromagnetic Ion Cyclotron Fluctuations and Fast Electron Scattering: Hybrid Simulations  

Microsoft Academic Search

Two dimensional electromagnetic hybrid simulations in a magnetized, homogeneous, collisionless plasma with a single ion species yield enhanced electromagnetic ion cyclotron (EMIC) fluctuations due to the growth of the ion cyclotron instability driven by T? i > T|| i. The research described here addresses fundamental properties of such enhanced fluctuations, in preparation for future studies on their interaction with fast

D. Winske; S. P. Gary

2008-01-01

121

Analysis of Microwave Electromagnetic Compatibility in Shielding Electronic System  

Microsoft Academic Search

An electromagnetic topology model used to analyse the High Power Microwave (HPM) effect on the different electrical components is presented. The model, whose foundation is linear coupling of aperture, emphasizes on the basic concept of electromagnetic topology, the abstract in the system analysis and two parameters: the polarization of electric field and the frequency of HPM. The algorithm of graph

Song Hang; Rao Yu-ping; Shao Ying; Zhou Dong-fang; Hu Tao; Niu Zhong-xia

2008-01-01

122

The Synchrotron Spectrum of Fast Cooling Electrons Revisited.  

PubMed

We discuss the spectrum arising from synchrotron emission by fast cooling (FC) electrons, when fresh electrons are continually accelerated by a strong blast wave, into a power-law distribution of energies. The FC spectrum has so far been described by four power-law segments divided by three break frequencies nusaelectron distribution. However, hot electrons are located right after the shock, while most electrons are farther downstream and have cooled. This spatial distribution changes the optically thick part of the spectrum, introducing a new break frequency, nuac

Granot; Piran; Sari

2000-05-10

123

Heating of the lower ionosphere electrons by electromagnetic radiation of lightning discharges  

SciTech Connect

This report investigates the heating effects on electrons that occur at the lower edge of the ionosphere due to the incidence of electromagnetic pulses radiated from discharges of lightning. Two tradiational models of the median return stroke is also considered.

Nickolaenko, A.P. [Institute of Radio Astronomy, Kharkov (Ukraine); Hayakawa, M. [Univ. of Electro-Communications, Tokyo (Japan)

1995-11-15

124

Polarization of Electrons in an Electromagnetic Wave Field in the Presence of Magnetic Field.  

National Technical Information Service (NTIS)

The possibility of electrons polarization in the field of circularly polarized electromagnetic wave at its propagation along the direction of constant homogeneous magnetic field is discussed for the case of small transverse and large longitudinal momenta ...

R. A. Melikyan

1986-01-01

125

Cooled electronic system with thermal spreaders coupling electronics cards to cold rails  

DOEpatents

Liquid-cooled electronic systems are provided which include an electronic assembly having an electronics card and a socket with a latch at one end. The latch facilitates securing of the card within the socket or removal of the card from the socket. A liquid-cooled cold rail is disposed at the one end of the socket, and a thermal spreader couples the electronics card to the cold rail. The thermal spreader includes first and second thermal transfer plates coupled to first and second surfaces on opposite sides of the card, and thermally conductive extensions extending from end edges of the plates, which couple the respective transfer plates to the liquid-cooled cold rail. The thermally conductive extensions are disposed to the sides of the latch, and the card is securable within or removable from the socket using the latch without removing the cold rail or the thermal spreader.

Chainer, Timothy J; Gaynes, Michael A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Schultz, Mark D; Simco, Daniel P; Steinke, Mark E

2013-07-23

126

Quasienergy functions of electrons in a semiconductor affected by an external electromagnetic field  

NASA Astrophysics Data System (ADS)

This paper is devoted to the study of the quasienergy spectrum and quasienergy functions of electrons in a semiconductor under the effect of a strong electromagnetic field whose frequency coincides with the forbidden band width. The case of a standing electromagnetic wave is analyzed. It is shown that in a standing wave the structure of the quasienergy spectrum is similar to that for quantum nonlinear resonance. An estimate of the frequency of electron nutation between valence and conduction bands is given.

Kolovskii, A. R.

1990-01-01

127

An electromagnetic energy harvester for powering consumer electronics  

NASA Astrophysics Data System (ADS)

This thesis introduces an electromagnetic vibratory energy harvester to power consumer electronics by generating electricity from the strides taken during walking or jogging. The harvester consists of a magnetic pendulum oscillating between two fixed magnets. The pendulum behaves similar to a rotor in a DC generator, while the fixed magnets, which are poled opposite to the pendulum, provide magnetic restoring forces similar to mechanical springs. When attached to a person's arm, the swinging motion subjects the magnetic pendulum to base excitations. Consequently, the pendulum oscillates near a stator which has three poles of wound copper coils. The motion of the pendulum induces a time-varying magnetic field in the flux path which generates electricity in the coils as per Faraday's law. To better understand the response behavior of the device, the thesis presents a nonlinear electromechanical model that describes the interaction between the mechanical and electrical subsystems. Experimental system identification is then implemented to characterize several unknown design parameters, including the nonlinear magnetic restoring torque, the mechanical damping coefficient, and the electromechanical coupling. The derived nonlinear mathematical model, which mimics the behavior of a damped Duffing oscillator, is then solved analytically using the method of multiple scales and the results are compared to experimental data showing good agreement for the design parameters considered. The performance of the device in charging a small battery while jogging is investigated. The motion of a typical swinging arm in terms of frequency and acceleration is reproduced on an electrodynamic shaker and used to charge a 100 ?Ah battery yielding an estimated charging time of 12 minutes.

Liu, Xiyuan

128

Electron beam electromagnetic field interaction in one-dimensional coaxial vircator  

NASA Astrophysics Data System (ADS)

A one-dimensional model of the interaction between an injected electron beam and an electromagnetic (EM) field inside a coaxial vircator is presented. The effects of the injected electron beam energy spread, anode absorption rate, feedback and injected current premodulation are analyzed. The EM-gains of interaction between the electron beam and TM01, TE11 modes are derived and discussed.

Shao, H.; Liu, G. Z.; Yang, Z. F.

2005-10-01

129

Relativistic electron pitch-angle scattering by electromagnetic ion cyclotron waves during geomagnetic storms  

Microsoft Academic Search

During magnetic storms, relativistic electrons execute nearly circular orbits about the Earth and traverse a spatially confined zone within the duskside plasmapause where electromagnetic ion cyclotron (EMIC) waves are preferentially excited. We examine the mechanism of electron pitch-angle diffusion by gyroresonant interaction with EMIC waves as a cause of relativistic electron precipitation loss from the outer radiation belt. Detailed calculations

Danny Summers; Richard M. Thorne

2003-01-01

130

Production of flickering aurora and field-aligned electron flux by electromagnetic ion cyclotron waves  

Microsoft Academic Search

Recent observations have suggested that flickering aurora is produced by a modulation of the field-aligned component of the electron flux within an auroral arc. It is proposed that a portion of the field-aligned electrons are of ionospheric origin and that these electrons are accelerated and their flux modulated by electromagnetic ion cyclotron waves that occur below the main acceleration region

M. Temerin; J. McFadden; M. Boehm; C. W. Carlson; W. Lotko

1986-01-01

131

Electromagnets  

NSDL National Science Digital Library

In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.

Vu Bioengineering Ret Program

132

Electron cooling system for ITEP ion storage ring  

NASA Astrophysics Data System (ADS)

The main goal of the Tera Watt A Cumulator project (Institute for Theoretical and Experimental Physics, Moscow) is accumulation in the storage ring of an intense ion beam, its longitudinal compression and the use of the extracted beam for plasma experiments. However, beam parameters at the target are decreased because of extreme transverse heating and growth of the beam momentum spread due to intrabeam scattering. These effects can be suppressed by application of the electron cooling system (ECS). Design study of ECS has been performed in the Joint Institute for Nuclear Research. The design project and characteristics of the system are described, as well as analysis of the accumulation kinetics in the presence of the cooling system. Design work has shown that because of the small length of the straight section (2.35 m), the effective length of the cooling system is small (about 55 60 cm). Nevertheless, for long accumulation times (>100 s), the system allows us to significantly improve the beam parameters at the target (specific energy, specific power, and so on) and to suppress the beam losses by an order of magnitude.

Zenkevich, P. R.; Alexeev, N. N.; Barkhudaryan, A. V.; Bolshakov, A. Ye.; Koshkarev, D. G.; Sharkov, Yu. V.; Bykovsky, V. F.; Korotaev, Yu. V.; Meshkov, I. N.; Sidorin, A. O.; Smirnov, A. V.; Syresin, Ye. M.; Titkova, I. V.

2002-07-01

133

Efficiency improvement of an electron collector intended for electron cooling systems using a Wien filter  

NASA Astrophysics Data System (ADS)

An efficient collector for high-voltage systems of electron cooling is presented. Its efficiency (ratio of the reflected electron current to the current of the main beam) is greatly improved by suppressing the reflected particle flux in the Wien filter. Secondary electrons deflect in crossed transverse electric and magnetic fields and are absorbed by a special receiver plate (secondary collector). The filter is designed so that the whole backward flow of electrons deflects even if the trajectory and main beam profile are distorted insignificantly. Experiments carried out on a special-purpose test bench show that such a filter raises the efficiency of the collector hundredfold (up to 10-6).

Bryzgunov, M. I.; Ivanov, A. V.; Panasyuk, V. M.; Parkhomchuk, V. V.; Reva, V. B.

2013-06-01

134

Numerical Investigation Based on CFD for Air Impingement Heat Transfer in Electronics Cooling  

Microsoft Academic Search

Air impingement cooling, as a potential air-cooling technique, has been shown to be much efficient and enabled to complement conventional forced convective air-cooling in electronics. To provide reliable references to the computational thermal analyses based on CFD for effective air-cooling technique integrated in microsystem electronics packaging, the numerical simulation based on CFD for air impingement heat transfer is conducted in

Yan Zhang; Jing-yu Fan; Johan Liu

2005-01-01

135

Cherenkov electromagnetic instability excited by an oscillating relativistic electron beam in ion channel  

SciTech Connect

The Cherenkov electromagnetic instability excited by an oscillating relativistic electron beam in ion channel has been studied. It is shown that the complex boundary with beam-ion channel-plasma system and the perturbation of electrons induce several electromagnetic-electrostatic hybrid slow waves, which offer the possibility to excite the instability. Under such conditions, the electronic betatron motion plays a decisive role in exciting the instability. The necessary and sufficient conditions inducing the instability have been given, and related physical mechanisms have been discussed. Furthermore, the influence of the parameters, such as accelerating voltage, on the width of instability band and the growth rate of the instability has been given.

Wang Zhenyu; Tang Changjian [Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu 610064 (China); Peng Xiaodong [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China)

2010-08-15

136

Cooling rate of thermal electrons by electron impact excitation of fine structure levels of atomic oxygen  

Microsoft Academic Search

The atomic oxygen fine structure cooling rate of thermal electrons based on new effective collision strengths for electron impact excitation of the ground-state 3P fine-structure levels in atomic oxygen have been fitted to an analytical expression which is available to the researcher for quick reference and accurate computer modeling with a minimum of calculations. We found that at the F

A. V. Pavlov; K. A. Berrington

1999-01-01

137

Screening effect in electromagnetic production of electron-positron pairs in relativistic nucleus-atom collisions  

SciTech Connect

We study the screening effects of the atomic electrons in the electromagnetic production of electron-positron pairs in relativistic nucleus-atom collisions for fixed target experiments. Our results are contrasted with those obtained in bare collisions, with particular attention given to its dependence on the beam energy and the target atom. {copyright} {ital 1999} {ital The American Physical Society}

Wu, J. [Department of Natural Sciences, Fayetteville State University, Fayetteville, North Carolina 28301 (United States); Derrickson, J.H.; Parnell, T.A. [NASA/Marshall Space Flight Center, Huntsville, Alabama 35812 (United States); Strayer, M.R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

1999-11-01

138

Support vector machine in application of modeling of electromagnetic pulse field coupling on electronic devices  

Microsoft Academic Search

The vulnerability of electronic devices to EMP (Electromagnetic Pulse) has been increased, and the assessment of EMP effects is the key to solving such problems. Furthermore, the simulation of EMP effects on electronic devices is an important means of assessing their effects. Targeting the universally existing complex computing process problems in mechanism modeling algorithm ubiquity, it have been researched that

Yang Nan; Wei Ming; Chen Xiang

2010-01-01

139

A Silicon / Tungsten Electromagnetic Calorimeter with Integrated Electronics  

SciTech Connect

We discuss progress and issues relevant to the design of a highly segmented silicon-tungsten electromagnetic calorimeter. Our design features a complete readout chip which is integrated onto each detector wafer, thus reducing the effective channel count by a factor of about 1000. We apply this design to the SD detector of the American LC Physics Group, but some elements could be applicable elsewhere.

Frey, R

2004-12-16

140

Semiclassical theory of relativistic electrons in space- and time-varying electromagnetic fields  

NASA Astrophysics Data System (ADS)

The geometric-optics theory for the Dirac equation is derived using a procedure developed for the description of electromagnetic waves in inhomogeneous plasmas. This semiclassical description of relativistic electrons permits simple estimates of the magnitude and relevance of quantum corrections to the classical particle dynamics which can be used to assess the validity of the classical treatment of relativistic electron beams in a variety of applications. Moreover, these results correct several errors in the literature and are presented in a form which is easily solved, numerically, using straightforward modifications of existing ray-tracing codes for electromagnetic radiation.

Jensen, R. V.; Bernstein, Ira B.

1984-01-01

141

Electrons in a relativistic-intensity laser field: generation of zeptosecond electromagnetic pulses and energy spectrum of the accelerated electrons  

SciTech Connect

We study the motion of an electron and emission of electromagnetic waves by an electron in the field of a relativistically intense laser pulse. The dynamics of the electron is described by the Newton equation with the Lorentz force in the right-hand side. It is shown that the electrons may be ejected from the interaction region with high energy. The energy spectrum of these electrons and the technique of using the spectrum to assess the maximal intensity in the focus are analysed. It is found that electromagnetic radiation of an electron moving in an intense laser field occurs within a small angle around the direction of the electron trajectory tangent. The tangent quickly changes its direction in space; therefore, electromagnetic radiation of the electron in the far-field zone in a certain direction in the vicinity of the tangent is a short pulse with a duration as short as zeptoseconds. The calculation of the temporary and spectral distribution of the radiation field is carried out. (superintense laser fields)

Andreev, A A; Galkin, A L; Kalashnikov, M P; Korobkin, V V; Romanovsky, Mikhail Yu; Shiryaev, O B [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2011-08-31

142

Electromagnetic secondary instabilities in electron temperature gradient turbulence  

NASA Astrophysics Data System (ADS)

The electron temperature gradient mode has been proposed as a primary mechanism for electron transport. The possibilities of magnetic secondary instabilities (``zonal'' magnetic fields and magnetic ``streamers'') are investigated as novel potential mechanisms for electron transport regulation and enhancement, respectively. In particular, zonal magnetic field growth and transport regulation is investigated as an alternative to electrostatic zonal flows. Growth rates and implications for electron thermal transport are discussed for both electrostatic and magnetic saturation mechanisms. The possibility of magnetic streamers (mesoscale radial magnetic fields), and their potential impact on electron thermal transport, is also considered.

Holland, C.; Diamond, P. H.

2002-09-01

143

The integration of liquid cryogen cooling and cryocoolers with superconducting electronic systems  

Microsoft Academic Search

The need for cryogenic cooling has been a critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of many of the superconducting circuits is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a serious disadvantage. This paper discusses the process of refrigerating superconducting devices with

Michael A Green

2003-01-01

144

Relativistic electron scattering by electromagnetic ion cyclotron ?uctuations: test particle simulations  

Microsoft Academic Search

Abstract. Relativistic electron scattering by electromagnetic ion cyclotron (EMIC) ?uctuations is studied using test particle computations coupled to a hybrid simulation code. The enhanced EMIC ?uctuations are derived from a one-dimensional, self-consistent hybrid simulation model and is due to the growth of the ion cyclotron instability driven by the ion temperature anisotropy, Ti? > Tik, in a magnetized, homogeneous, collisionless

K. Liu; D. S. Lemons; D. Winske; S. P. Gary

2009-01-01

145

Relativistic Electron Scattering by Electromagnetic Ion Cyclotron Fluctuations: Test Particle Simulations  

Microsoft Academic Search

Relativistic electron scattering by electromagnetic ion cyclotron (EMIC) fluctuations is studied using a test particle simulation code. The EMIC fluctuation input comes from a one dimensional, self-consistent hybrid simulation model and is due to the growth of the ion cyclotron instability driven by the ion temperature anisotropy, Ti > Ti, in a magnetized, homogeneous, collisionless plasma with a single ion

Kaijun Liu; Don S. Lemons; Dan Winske; S. Peter Gary

2009-01-01

146

The excitation of coherent electromagnetic radiation in plasma waveguides by relativistic electron beams  

Microsoft Academic Search

A theoretical analysis is presented of the interaction between a monoenergetic relativistic electron beam and a bounded plasma and the conditions for the generation of electromagnetic radiation in a single mode by such a system are derived. Two specific geometries are considered: (a) a metallic waveguide of radius R, completely filled with plasma which is penetrated by a beam of

B. I. Aronov; L. S. Bogdankevich; A. A. Rukhadze

1976-01-01

147

Excitation of Electromagnetic Waves by an Electron Ring Beam in a Magnetized Plasma Waveguide  

Microsoft Academic Search

We study the resonant interactions between an electron ring beam and plasma waveguide modes. This is motivated by the research of radio emission in low solar corona. We consider a density-depleted duct (above an active region near a flare site) that may be treated as a magnetized plasma waveguide. The electromagnetic waves excited in the waveguide are classified into the

Guo-Cheng Zhou; Ching-Sheng Wu; De-Ju Wang; Yan-Ping Chen

2002-01-01

148

Study of harmonic generated by electromagnetic and electronic ballast used in street lighting  

Microsoft Academic Search

In this paper, several high power lighting networks based on high pressures sodium (HPS) lamps have been set up. These have been chosen because of they are used in public lighting. Both electromagnetic and electronic ballast have been used with the mentioned lamps. They have also been tested with different levels of power using dimming for a 220 V power

A. Gil-de-Castro; A. Moreno-Munoz; J. M. Flores Arias; V. Pallares-Lopez

2011-01-01

149

Effects of trapped electrons on electromagnetic fields in an oblique shock wave  

SciTech Connect

A magnetosonic shock wave propagating obliquely to an external magnetic field can trap electrons and accelerate them to ultrarelativistic energies. The effect of trapped electrons on electromagnetic fields in a shock wave is studied by theory and particle simulations. The expressions for field strengths are analytically obtained, including the number of trapped electrons n{sub t} as a factor. It is shown that as n{sub t} increases, the magnitude of F increases, where F is the integral of the parallel electric field, E{sub ||}=(E{center_dot}B)/B, along B. Theoretical analysis also suggests that the increase in F causes the electrons to be trapped deeper and accelerated to higher kinetic energies. These theoretical predictions are verified with relativistic electromagnetic particle simulations.

Toida, Mieko; Shikii, Kenta [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

2009-11-15

150

Low frequency electromagnetic oscillations in dense degenerate electron-positron pair plasma, with and without ions  

SciTech Connect

Quantum plasma oscillations are studied in a strongly magnetized, ultra-dense plasma with degenerate electrons and positrons. The dispersive role of electron and positron quantum effects on low frequency (in comparison to electron cyclotron frequency) shear electromagnetic wave is investigated by employing hydrodynamic formulation. In the presence of ions, the density balance changes, and the electromagnetic wave (with frequency lower than the ion cyclotron frequency) is shown to couple with electrostatic ion mode under certain conditions. For such low frequency waves, it is also seen that the contribution of electron and positron degeneracy pressure is dominant as compared to their diffraction effects. The results are analyzed numerically for illustrative purpose pointing out their relevance to the dense laboratory (e.g., super-intense laser-dense matter interactions) and astrophysical plasmas.

Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Ayub, M. K. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Pohang University of Science and Technology (POSTECH), Pohang, Gyunbuk 790-784 (Korea, Republic of); Ahmad, Ali [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

2012-10-15

151

Status of the R&D Towards Electron Cooling of RHIC  

SciTech Connect

The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed cooling calculations have been made to determine the efficacy of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. Electron cooling of RHIC at collisions requires electron beam energy up to about 54 MeV at an average current of between 50 to 100 mA and a particularly bright electron beam. The accelerator chosen to generate this electron beam is a superconducting Energy Recovery Linac (ERL) with a superconducting RF gun with a laser-photocathode. An intensive experimental R&D program engages the various elements of the accelerator: Photocathodes of novel design, superconducting RF electron gun of a particularly high current and low emittance, a very high-current ERL cavity and a demonstration ERL using these components.

A. Favale; D. Holmes; J.J. Sredniawski; Hans Bluem; M.D. Cole; J. Rathke; T. Schultheiss; A.M.M. Todd; V.V. Parkhomchuk; V.B. Reva; J. Alduino; D.S. Barton; Dana Richard Beavis; I. Ben-Zvi; Michael Blaskiewicz; J.M. Brennan; Andrew Burrill; Rama Calaga; P. Cameron; X. Chang; K.A. Drees; A.V. Fedotov; W. Fischer; G. Ganetis; D.M. Gassner; J.G. Grimes; Hartmut Hahn; L.R. Hammons; A. Hershcovitch; H.C. Hseuh; D. Kayran; J. Kewisch; R.F. Lambiase; D.L. Lederle; Vladimir Litvinenko; C. Longo; W.W. MacKay; G.J. Mahler; G.T. McIntyre; W. Meng; B. Oerter; C. Pai; George Parzen; D. Pate; D. Phillips; S.R. Plate; Eduard Pozdeyev; Triveni Rao; J. Reich; Thomas Roser; A.G. Ruggiero; T. Russo; C. Schultheiss; Z. Segalov; J. Smedley; K. Smith; T. Tallerico; S. Tepikian; R. Than; R.J. Todd; Dejan Trbojevic; J.E. Tuozzolo; P. Wanderer; G. WANG; D. Weiss; Q. Wu; Kin Yip; A. Zaltsman; A. Burov; S. Nagaitsev; L.R. Prost; A.O. Sidorin; A.V. Smirnov; Yaroslav Derbenev; Peter Kneisel; John Mammosser; H. Phillips; Joseph Preble; Charles Reece; Robert Rimmer; Jeffrey Saunders; Mircea Stirbet; Haipeng Wang; A.V. Aleksandrov; D.L. Douglas; Y.W. Kang; D.T. Abell; G.I. Bell; David L. Bruhwiler; R. Busby; John R. Cary; D.A. Dimitrov; P. Messmer; Vahid Houston Ranjbar; D.S. Smithe; A.V. Sobol; P. Stoltz

2007-08-01

152

Electron-beam mapping of plasmon resonances in electromagnetically interacting gold nanorods  

SciTech Connect

Electron energy-loss spectroscopy and energy-filtered transmission electron-microscope imaging are used to characterize the energy distribution of the surface plasmon of isolated and coupled gold nanorods. Local-field enhancement and spectral shift of the plasmon modes are observed for two interacting nanoparticles. The spatial modes measured by energy loss are shown to share qualitative similarities with the electromagnetic field distribution around gold nanorods induced by optical excitation as simulated using the discrete dipole-approximation method.

N'Gom, Moussa; Li Shuzhou; Schatz, George; Erni, Rolf; Agarwal, Ashish; Kotov, Nicholas; Norris, Theodore B. [Applied Physics Department and Center for Ultrafast Optical Sciences, University of Michigan-Ann Arbor, Ann Arbor, Michigan 48109 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113 (United States); National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 72-150, Berkeley, California 94720 (United States); Chemical Engineering Department, University of Michigan-Ann Arbor, Ann Arbor, Michigan 48109 (United States); EECS Department and Center for Ultrafast Optical Sciences, University of Michigan-Ann Arbor, Ann Arbor, Michigan 48109 (United States)

2009-09-15

153

Nonlinear saturation and thermal effects on the free electron laser using an electromagnetic pump  

Microsoft Academic Search

The production of visible laser radiation by a low energy relativistic electron beam (MeV) is most readily accomplished through the use of a high frequency (far infrared) electromagnetic pump (?r=?0\\/4?02); such radiation can be generated by reflecting the radiation the relativistic electron beam generates when it interacts with a rippled static magnetic field. It is important to investigate what limits

A. T. Lin; J. M. Dawson

1980-01-01

154

The effect of fan-reliability and cooling-performance on electronic-chassis reliability  

Microsoft Academic Search

A tractable model for predicting the failure rates of electronic chassis cooled by fans with finite failure rates is developed. The model accounts for two regimes prior to electronics failure: the electronic chassis is operated at a temperature which occurs with a fan that is operational and the electronic chassis is operated at a temperature which occurs when the fan

John M. Hogan; Valley Forge; Reader Aids

1993-01-01

155

Disorder-Assisted Electron-Phonon Scattering and Cooling Pathways in Graphene  

NASA Astrophysics Data System (ADS)

We predict that graphene is a unique system where disorder-assisted scattering (supercollisions) dominates electron-lattice cooling over a wide range of temperatures, up to room temperature. This is so because for momentum-conserving electron-phonon scattering the energy transfer per collision is severely constrained due to a small Fermi surface size. The characteristic T3 temperature dependence and power-law cooling dynamics provide clear experimental signatures of this new cooling mechanism. The cooling rate can be changed by orders of magnitude by varying the amount of disorder providing means for a variety of new applications that rely on hot-carrier transport.

Song, Justin C. W.; Reizer, Michael Y.; Levitov, Leonid S.

2012-09-01

156

Equilibrium values between intrabeam scattering and electron cooling  

Microsoft Academic Search

A simple relation which gives equilibrium emittances between intrabeam scattering and cooling in low energy storage rings is deduced from computer simulations. The lattice dependence is described with a constant which is independent of, e.g., energy, charge or cooling times. Different plots for CRYRING are shown.

Ansgar Simonsson

1989-01-01

157

Investigations of Electromagnetic Behavior and Interaction of Motion Control Electronic Devices  

NASA Astrophysics Data System (ADS)

As some actual or future prototypes for electronic motion control are designed with higher chip density and constraints for integration challenges, new electromagnetic interactions and compatibility cases have to be considered and modeled to prevent really bad electromagnetic compliance and less-of-motion risks. In consequence, the reliability and the functionalities of the embedded system itself can be affected. First this chapter deals with emission and immunity studies combined with temperature influence on electronic devices used to control power electronic motion modules. Specific Thermal-EM test setup and boards especially developed for these investigations are described. Then experimental results and first approaches of global modeling work for this issue on modern PCB technology are discussed.

Dienot, J.-M.

158

STATUS OF THE RESEARCH AND DEVELOPMENT TOWARDS ELECTRON COOLING OF RHIC  

SciTech Connect

The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed calculations were made of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. The electron beam accelerator will be a superconducting Energy Recovery Linac (ERL). An intensive experimental R&D program engages the various elements of the accelerator, as described by 24 contributions to the 2007 PAC.

BEN-ZVI,I.; OZAKI, T.; YOSHIDA, T.; NANKAWA, T.; KOZAI, N.; SAKAMOTO, F.; SUZUKI, Y.

2007-06-25

159

Status of the R&D towards electron cooling of RHIC  

SciTech Connect

The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed calculations were made of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. The electron beam accelerator will be a superconducting Energy Recovery Linac (ERL). An intensive experimental R&D program engages the various elements of the accelerator, as described by 24 contributions to the 2007 PAC.

Ben-Zvi, I.; Alduino, J.; Barton, D.; Beavis, D.; Blaskiewicz, M.; Brennan, J.M.; Burrill, A.; Calaga, R.; Cameron, P.; Chang, X.; Drees, K.; /Brookhaven /AES, Medford /Novosibirsk, IYF /Fermilab /Dubna, JINR /Jefferson Lab /Oak Ridge /NIST, Boulder

2007-06-01

160

Electromagnetic Particle-in-Cell Simulations of Electron Holes Formed During the Electron Two-Stream Instability  

NASA Astrophysics Data System (ADS)

Previous electrostatic particle-in-cell (PIC) simulations have pointed out that electron phase-space holes (electron holes) can be formed during the nonlinear evolution of the electron two-stream instability. The parallel cuts of the parallel and perpendicular electric field have bipolar and unipolar structures in these electron holes, respectively. In this study, two-dimensional (2D) electromagnetic PIC simulations are performed in the x - y plane to investigate the evolution of the electron two-stream instability, with the emphasis on the magnetic structures associated with these electron holes in different plasma conditions. In the simulations, the background magnetic field is along the x direction. In weakly magnetized plasma (?e < ?pe, where ?e and ?pe are the electron gyrofrequency and electron plasma frequency, respectively), several 2D electron holes are formed. In these 2D electron holes, the parallel cut of the fluctuating magnetic field ?Bx and ?Bz has unipolar structures, while the fluctuating magnetic field ?By has bipolar structures. In strongly magnetized plasma (?e > ?pe), several quasi-1D electron holes are formed. The electrostatic whistler waves with streaked structures of Ey are excited. The fluctuating magnetic field ?Bx and ?Bz also have streaked structures. The fluctuating magnetic field ?Bx and ?By are produced by the current in the z direction due to the electric field drift of the trapped electrons, while the fluctuating magnetic field ?Bz can be explained by the Lorentz transformation of a moving quasielectrostatic structure. The influences of the initial temperature anisotropy on the magnetic structures of the electron holes are also analyzed. The electromagnetic whistler waves are found to be excited in weakly magnetized plasma. However, they do not have any significant effects on the electrostatic structures of the electron holes.

Wu, Mingyu; Lu, Quanming; Zhu, Jie; Wang, Peiran; Wang, Shui

2013-01-01

161

Modulational instability of electromagnetic electron-cyclotron wave packets in the magnetosphere with non-Maxwellian electron distribution  

SciTech Connect

The satellite observations of the magnetosphere in the low-frequency ion dynamics revealed several facts: (1) localized structures for electric field signal parallel to the magnetic field; (2) anisotropy for the electron velocity distribution such that T{sub perpendicular}<electrons. Based on these evidences, a nonlinear model is presented to develop the electromagnetic electron-cyclotron (EMEC) theory to the non-Maxwellian plasmas. Then, the modulational instability analysis of EMEC waves is investigated.

Abbasi, H. [Faculty of Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Hakimi Pajouh, H. [Department of Physics, Alzahra University, Tehran 19834 (Iran, Islamic Republic of)

2008-09-15

162

Interaction of electromagnetic waves and suprathermal electrons in the near-critical electric field limit  

NASA Astrophysics Data System (ADS)

The velocity-space anisotropy of suprathermal electron distributions is a source of free energy that may destabilize plasma waves through a resonant interaction between the waves and the energetic electrons. In this work we use a suprathermal electron distribution appropriate for the case when the accelerating electric field is near-critical and we investigate the frequencies, wave numbers and propagation angles of the most unstable waves using a general dispersion relation. It is shown that if the electric field is sub-critical, the anisotropy is not enough to drive electromagnetic waves unstable, as the Landau damping of the waves overwhelms the drive through the anomalous Doppler resonance. In the case when the electric field is supercritical, two types of electromagnetic waves will be destabilized, the electron-whistler and the extraordinary electron wave. The number of electrons for destabilization of the latter is several orders of magnitude lower than for the electron-whistler wave. Consequently, the threshold for destabilization of the extraordinary electron wave is much lower.

Kómár, A.; Pokol, G. I.; Fülöp, T.

2012-12-01

163

Scaling laws with current for equilibrium momentum spread and emittances from intrabeam scattering and electron cooling  

NASA Astrophysics Data System (ADS)

Based on the theories of Piwinski, Bjorken-Mtingawa and Martini of Coulomb scattering, expressions for the heating rates due to intrabeam scattering were known since a long time. Simplifications by Wei-Parzen and Rao and Piwinski led to analytic approximations which are easily applicable to existing lattices. We use these approximations and also the formulae from thermal equilibration of Struckmeier and equate them to either constant cooling rates from electron cooling or to the Novosibirsk cooling rates for electron cooling to calculate the equilibrium values of the horizontal and vertical emittances and the momentum spread (longitudinal emittance) for typical beams in the ESR or in the HESR. For constant cooling and all approximation formulae the ratio of current to the product of the three emittances remains almost constant. This yields a slope of the momentum spread with current between 0.2 and 0.3, in agreement with experimental data. Using the Novosibirsk cooling rates this slope is much larger.

Hasse, R. W.; Boine-Frankenheim, O.

2004-10-01

164

Electromagnetic absorption in an electron - hole double-layer system in a magnetic field  

NASA Astrophysics Data System (ADS)

The high-frequency magnetoconductivity for a double-layer electron - hole system is calculated at finite temperature. The formalism rests on the temperature Green's function and Kubo's formula for conductivity. It is found that at frequencies higher than the cyclotron frequencies of electrons and holes, the frequency-dependent electromagnetic absorption exhibits oscillatory behaviour. The maxima in the absorption coefficient correspond to a situation where the photon energy is approximately the sum of the energies of the electron pair and the hole pair which are simultaneously excited by the radiation field.

Zhang, C.; Chao, K. A.

1997-09-01

165

Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma  

SciTech Connect

Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2012-07-15

166

External Compton Emission in Blazars of Nonlinear Synchrotron Self-Compton-cooled Electrons  

NASA Astrophysics Data System (ADS)

The origin of the high-energy component in spectral energy distributions (SEDs) of blazars is still something of a mystery. While BL Lac objects can be successfully modeled within the one-zone synchrotron self-Compton (SSC) scenario, the SED of low-peaked flat spectrum radio quasars is more difficult to reproduce. Their high-energy component needs the abundance of strong external photon sources, giving rise to stronger cooling via the inverse Compton (IC) channel, and thus to a powerful component in the SED. Recently, we have been able to show that such a powerful inverse Compton component can also be achieved within the SSC framework. This, however, is only possible if the electrons cool by SSC, which results in a nonlinear process, since the cooling depends on an energy integral over the electrons. In this paper, we aim to compare the nonlinear SSC framework with the external Compton (EC) output by calculating analytically the EC component with the underlying electron distribution being either linearly or nonlinearly cooled. Due to the additional linear cooling of the electrons with the external photons, higher number densities of electrons are required to achieve nonlinear cooling, resulting in more powerful IC components. If the electrons initially cool nonlinearly, the resulting SED can exhibit a dominant SSC over the EC component. However, this dominance depends strongly on the input parameters. We conclude that, with the correct time-dependent treatment, the SSC component should be taken into account in modeling blazar flares.

Zacharias, Michael; Schlickeiser, Reinhard

2012-12-01

167

EXTERNAL COMPTON EMISSION IN BLAZARS OF NONLINEAR SYNCHROTRON SELF-COMPTON-COOLED ELECTRONS  

SciTech Connect

The origin of the high-energy component in spectral energy distributions (SEDs) of blazars is still something of a mystery. While BL Lac objects can be successfully modeled within the one-zone synchrotron self-Compton (SSC) scenario, the SED of low-peaked flat spectrum radio quasars is more difficult to reproduce. Their high-energy component needs the abundance of strong external photon sources, giving rise to stronger cooling via the inverse Compton (IC) channel, and thus to a powerful component in the SED. Recently, we have been able to show that such a powerful inverse Compton component can also be achieved within the SSC framework. This, however, is only possible if the electrons cool by SSC, which results in a nonlinear process, since the cooling depends on an energy integral over the electrons. In this paper, we aim to compare the nonlinear SSC framework with the external Compton (EC) output by calculating analytically the EC component with the underlying electron distribution being either linearly or nonlinearly cooled. Due to the additional linear cooling of the electrons with the external photons, higher number densities of electrons are required to achieve nonlinear cooling, resulting in more powerful IC components. If the electrons initially cool nonlinearly, the resulting SED can exhibit a dominant SSC over the EC component. However, this dominance depends strongly on the input parameters. We conclude that, with the correct time-dependent treatment, the SSC component should be taken into account in modeling blazar flares.

Zacharias, Michael; Schlickeiser, Reinhard, E-mail: mz@tp4.rub.de, E-mail: rsch@tp4.rub.de [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2012-12-20

168

A Unique Approach to Power Electronics and Motor Cooling in a Hybrid Electric Vehicle Environment  

SciTech Connect

An innovative system for cooling the power electronics of hybrid electric vehicles is presented. This system uses a typical automotive refrigerant R-134a (1,1,1,2 tetrafluoroethane) as the cooling fluid in a system that can be used as either part of the existing vehicle passenger air conditioning system or separately and independently of the existing air conditioner. Because of the design characteristics, the cooling coefficient of performance is on the order of 40. Because liquid refrigerant is used to cool the electronics directly, high heat fluxes can result while maintaining an electronics junction temperature at an acceptable value. In addition, an inverter housing that occupies only half the volume of a conventional inverter has been designed to take advantage of this cooling system. Planned improvements should result in further volume reductions while maintaining a high power level.

Ayers, Curtis William [ORNL; Hsu, John S [ORNL; Lowe, Kirk T [ORNL; Conklin, Jim [ORNL

2007-01-01

169

Optimal design methodology of plate-fin heat sinks for electronic cooling using entropy generation strategy  

Microsoft Academic Search

This paper presents a formal systematic optimization process to plate-fins heat sink design for dissipating the maximum heat generation from electronic component by applying the entropy generation rate to obtain the highest heat transfer efficiency. The design investigations demonstrate the thermal performance with horizontal inlet cooling stream is slightly superior to that with vertical inlet cooling stream. However, the design

C. J. Shih; G. C. Liu

2004-01-01

170

Thermohydraulic Dynamics and Fuzzy Coordination Control of a Microchannel Cooling Network for Space Electronics  

Microsoft Academic Search

This paper presents the dynamic model, analysis, and fuzzy control of a microchannel-heat-exchanger (MHE) space cooling network for dissipating exhaust heat of onboard electronic components inside spacecraft to the outer space environment. Along with a method for modeling a nonlinear fluid resistance network, a detailed analysis of flow rate changes and temperature transients of the MHE cooling network is given,

Yun-Ze Li; Kok-Meng Lee

2011-01-01

171

Theory of the friction force using electron cooling as an intrabeam scattering process  

Microsoft Academic Search

Using the results found previously for the cooling rates of the emittances, due to collisions between the electrons and the ions, a result is found for the friction force acting on the ions. It is shown that the friction force found here when used to track the ion bunch will give the same emittance cooling rates as those found using

George Parzen

2007-01-01

172

Recent progress of Carbon Nanotubes as cooling fins in electronic packaging  

Microsoft Academic Search

As power density in electronic system is approaching a level that conventional cooling methods canpsilat handle, reliability of microsystems is of large concern. In this paper, novel schemes for heat dissipation on electrical components have been reviewed with a strong focus on using carbon nanotubes (CNTs) as cooling fins as a basic approach. With an extraordinary high thermal conductivity, CNT

Johan Liu; Yifeng Fu; Teng Wang

2008-01-01

173

Electron cooling of high-Z ion beams parallel to a guide magnetic field  

Microsoft Academic Search

The cooling of high-Z ion beams through collisions with electrons whose temperature parallel to a guide magnetic field is considerably lower than their perpendicular temperature is considered. For initial electron temperatures, magnetic fields, and charged-particle densities, electrons tend to be trapped in the vicinity of their nearest ion neighbor. This results in an energy exchange with the ions that is

S. ROBERT GOLDMAN; I. Hoffmann

1990-01-01

174

Modulational behavior of electromagnetic waves in ultra-relativistic electron-positron plasmas  

NASA Astrophysics Data System (ADS)

The dynamical properties of electromagnetic (EM) waves in ultra-relativistic electron-positron (EP) plasmas are analytically investigated on the basis of the nonlinear governing equations obtained from a kinetic way. It is shown that the EM wave envelope will collapse and be trapped into a localized region for the modulation interaction with low frequency density variation induced by ponderomotive force. The correlation between the localized strong wave field and the pulsar radio emission is discussed.

Liu, Y.; Liu, S. Q.; Dai, B.

2013-07-01

175

Relativistic electron scattering by electromagnetic ion cyclotron fluctuations: Test particle simulations  

Microsoft Academic Search

Relativistic electron scattering by electromagnetic ion cyclotron (EMIC) fluctuations is studied using test particle computations coupled to the results of a hybrid simulation code. The enhanced EMIC fluctuations are derived from a 1-D, self-consistent hybrid simulation model and are due to the growth of the Alfvén cyclotron instability driven by the ion temperature anisotropy, Ti$\\\\perp$ > Ti$\\\\parallel$ (where the subscripts

Kaijun Liu; Don S. Lemons; Dan Winske; S. Peter Gary

2010-01-01

176

Interference to digital avionics due to electromagnetic radiation from personal electronic devices carried aboard aircraft  

Microsoft Academic Search

The possibility of interference due to electromagnetic radiation from portable consumer-type electronic devices has been known for some time. Until recently, there has not been significant problems with interference primarily due to the low frequency and low energy circuits typically found in battery-operated portable equipment. With the steadily increasing clock speeds of so-called “lap top” computers, the potential for interference

A. Helfrick

1994-01-01

177

A vibration-based electromagnetic energy harvester system with highly efficient interface electronics  

Microsoft Academic Search

This paper presents a vibration-based electromagnetic (EM) energy harvester system utilizing novel and highly efficient interface electronics. The energy harvesting module up-converts the environmental low frequency vibrations for increased AC power output. The interface circuit employs a boot-strap technique to reduce the threshold voltage of the rectifiers further increasing the power conversion efficiency of the overall system. The complete system,

Arian Rahimi; Ozge Zorlu; Ali Muhtaroglu; Haluk Kulah

2011-01-01

178

Photino bremsstrahlung in intense electromagnetic fields  

Microsoft Academic Search

We calculate the probability for the emission of a pair of photinos by an electron moving in a background electromagnetic field. The rate of the process e ? e?? is estimated at different values of the field strength and electron energies. Comparing the cooling rate of some astrophysical objects via photino bremsstrahlung with another competing energy-loss mechanism we find new

Alexander V. Kurilin; Aleksey I. Ternov

1996-01-01

179

Electromagnetic diffraction radiation of a subwavelength-hole array excited by an electron beam.  

PubMed

This paper explores the physics of the electromagnetic diffraction radiation of a subwavelength holes array excited by a set of evanescent waves generated by a line charge of electron beam moving parallel to the array. Activated by a uniformly moving line charge, numerous physical phenomena occur such as the diffraction radiation on both sides of the array as well as the electromagnetic penetration or transmission below or above the cut-off through the holes. As a result the subwavelength holes array becomes a radiation array. Making use of the integral equation with relevant Green's functions, an analytical theory for such a radiation system is built up. The results of the numerical calculations based on the theory agree well with that obtained by the computer simulation. The relation among the effective surface plasmon wave, the electromagnetic penetration or transmission of the holes and the diffraction radiation is revealed. The energy dependence of and the influence of the hole thickness on the diffraction radiation and the electromagnetic penetration or transmission are investigated in detail. Therefore, a distinct diffraction radiation phenomenon is discovered. PMID:19905233

Liu, Shenggang; Hu, Min; Zhang, Yaxin; Li, Yuebao; Zhong, Renbin

2009-09-10

180

Rashba fields in a two-dimensional electron gas at electromagnetic spin resonance  

NASA Astrophysics Data System (ADS)

We present an analysis of the Rashba effects in a two-dimensional electron gas induced by the microwave electric and magnetic fields. We show that in the frame of the Drude model the Rashba interaction can be described by magnetic and electric corrections affecting the spin and the velocity of the electrons. We describe the rf currents making use of the conductivity tensor formalism. The electromagnetic power absorption is obtained as a function of the external electric and magnetic rf fields up to the second order of the Rashba parameter. The channels of energy transfer due to Rashba field corrections are analyzed.

Ungier, W.; Jantsch, W.

2013-09-01

181

Regime of capture of electron bunches by a backward electromagnetic wave in a longitudinal electrostatic field  

NASA Astrophysics Data System (ADS)

The regime of capture of electron bunches is considered for the case in which the phase and the group velocities of the electromagnetic field are of opposite signs (backward wave field). It is also assumed that the electrons flow in the same direction as the phase of the synchronous spatial harmonic of the EM field. In the case of an accelerating electrostatic field the efficiency of energy conversion increases for smaller initial bunch phase width. In the case of a retarding electrostatic field the longitudinal decrease in the bunch phase width is noted as the primary benefit of the energy conversion mechanism described. Results are presented for an O-type BWT.

Beliavskii, E. D.

182

Combined Laser and Electron Cooling of Bunched C3+ Ion Beams at the Storage Ring ESR  

SciTech Connect

We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at an energy of 1.46 GeV at the ESR (GSI). Despite for the high beam energy and charge state laser cooling provided a reduction of the momentum spread of one order of magnitude in space-charge dominated bunches as compared to electron cooling. For ion currents exceeding 10 {mu}A intra-beam-scattering losses could not be compensated by the narrow band laser system presently in use. Yet, no unexpected problems occurred encouraging the envisaged extension of the laser cooling to highly relativistic beams. At ESR, especially the combination with modest electron cooling provided three-dimensionally cold beams in the plasma parameter range of unity, where ordering effects can be expected and a still unexplained signal reduction of the Schottky signal is observed.

Schramm, U.; Bussmann, M.; Habs, D. [Department fuer Physik, LMU Muenchen, 85748 Garching (Germany); Kuehl, T.; Beller, P.; Franzke, B.; Nolden, F.; Steck, M. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Saathoff, G.; Reinhardt, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Karpuk, S. [Institut fuer Physik, Universitaet Mainz, Mainz (Germany)

2006-03-20

183

The integration of liquid cryogen cooling and cryocoolers withsuperconducting electronic systems  

SciTech Connect

The need for cryogenic cooling has been a critical issuethat has kept superconducting electronic devices from reaching the marketplace. Even though the performance of many of the superconductingcircuits is superior to silicon electronics, the requirement forcryogenic cooling has put the superconducting devices at a seriousdisadvantage. This report discusses the process of refrigeratingsuperconducting devices with cryogenic liquids and small cryocoolers.Three types of cryocoolers are compared for vibration, efficiency, andreliability. The connection of a cryocooler to the load is discussed. Acomparison of using flexible copper straps to carry the heat load andusing heat pipe is shown. The type of instrumentation needed formonitoring and controlling the cooling is discussed.

Green, Michael A.

2003-07-09

184

A Comparison of Hybrid Electric Vehicle Power Electronics Cooling Options  

Microsoft Academic Search

This study quantifies the heat dissipation potential of three inverter package configurations over a range of control factors. These factors include coolant temperature, number of sides available for cooling, effective heat transfer coefficient, maximum semiconductor junction temperature, and interface material thermal resistance. Heat dissipation potentials are examined in contrast to a research goal to use 105degC coolant and dissipate 200

M. O'Keefe; K. Bennion

2007-01-01

185

Materials selection for electronic enclosures in space environment considering electromagnetic interference effect  

NASA Astrophysics Data System (ADS)

Using low power electronic devices for space applications to reduce the mass and energy consumption has lead to electromagnetic interference (EMI) problem. Electronic enclosures are used to shield electronic devices against EMI. In the past, electromagnetic shielding has been mainly the only criteria considered in electronic enclosure design. However, there are several structural and thermal requirements for selection of shielding materials which should also be taken into account. In this research work, three quantitative materials selection methods, i.e. Digital Logic (DL), Modified Digital Logic (MDL), and Z-transformation, are employed to select the best material from among a list of candidate materials. Composite and metallic electronic enclosures are explored and the best material is selected. Z-transformation method is applicable to both of the considered case studies while DL and MDL can only be used for solving one of them. Z-transformation method ranks aluminum as the first choice among various metallic materials. The wide range of Z-transformation application and its practical results confirm the superiority of Z-transformation method over DL and MDL methods.

Fayazbakhsh, K.; Abedian, A.

2012-02-01

186

Perspectives for a high energy electron cooling at lear an experimental test  

SciTech Connect

The feasibility of a high energy electron cooling device, has been studied through tests on a prototype of the electron device. The apparatus consists of a pulsed (20/60 KeV, 2 s) electron gun, a drift region 1 m long and a depressed collector to recover the electron energy. Tests on beam optics and energy recovery have been performed, a high efficiency for energy recovery has been obtained. The high energy device project is in progress.

Biagini, M.E.; Bizzarri, U.; Calabrese, R.; Conte, M.; Guiducci, S.; Petrucci, F.; Picardi, L.; Ronsivalle, C.; Savrie, M.; Slavetti, G.

1985-10-01

187

Two-dimensional electromagnetic Child-Langmuir law of a short-pulse electron flow  

SciTech Connect

Two-dimensional electromagnetic particle-in-cell simulations were performed to study the effect of the displacement current and the self-magnetic field on the space charge limited current density or the Child-Langmuir law of a short-pulse electron flow with a propagation distance of {zeta} and an emitting width of W from the classical regime to the relativistic regime. Numerical scaling of the two-dimensional electromagnetic Child-Langmuir law was constructed and it scales with ({zeta}/W) and ({zeta}/W){sup 2} at the classical and relativistic regimes, respectively. Our findings reveal that the displacement current can considerably enhance the space charge limited current density as compared to the well-known two-dimensional electrostatic Child-Langmuir law even at the classical regime.

Chen, S. H.; Tai, L. C.; Liu, Y. L. [Department of Physics, National Central University, Jhongli 32001, Taiwan (China); Ang, L. K. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Koh, W. S. [Institute of High Performance Computing, A-STAR, Singapore 138632 (Singapore)

2011-02-15

188

Electromagnetic solitons in fully relativistic electron-positron plasmas with finite temperature  

SciTech Connect

The existence of localized structure of electromagnetic waves in relativistic electron-positron plasmas is investigated based on the pseudo-potential theory, without making any assumptions on the magnitudes of the flow velocity and temperature of the medium. The conditions for the localization of electromagnetic wave in the form of dark (dip type) soliton are found. In the small amplitude approximation, it is found that the dip becomes deeper and narrower as the temperature is raised. In low temperature T << mc{sup 2}, localized solution exists only if the equilibrium longitudinal fluid velocity (parallel to the direction of propagation) in the wave frame is larger than the classical thermal velocity {radical}(T/m) of the plasma. For ultra-relativistically high temperature T >> mc{sup 2}, it is shown that dark soliton can exist if the equilibrium longitudinal velocity is larger than c/{radical}(3).

Lee, Nam C. [Department of Physics, Pusan National University, Busan 609-735 (Korea, Republic of)

2011-06-15

189

Metamorphic materials: bulk electromagnetic transitions realized in electronically reconfigurable composite media.  

PubMed

We present what we believe is a new class of composite electromagnetic materials characterized by the concept of metamorphism, which we define in general terms. Metamorphic materials exhibit bulk electromagnetic transitions among states characterized by distinct ranges of values of their reflection coefficient. Each such state has unique physical properties induced by the corresponding values of the reflection coefficient. We present a variety of physical realizations of the concept of metamorphic materials in microwave frequencies, showing with specific metallodielectric designs how transitions among metamorphic states can be obtained at the same frequency, for fixed material geometries, by electronic reconfigurability. We further show how a given material exhibiting certain metamorphic states at a given frequency can transform into a different combination of metamorphic states at different frequencies; i.e., metamorphic materials have a useful dispersive degree of freedom. PMID:17047724

Kyriazidou, Chryssoula A; Contopanagos, Harry F; Alexopoulos, Nicolaos G

2006-11-01

190

Guidance note: risk management of workers with medical electronic devices and metallic implants in electromagnetic fields.  

PubMed

Medical electronic devices and metallic implants are found in an increasing number of workers. Industrial applications requiring intense electromagnetic fields (EMF) are growing and the potential risk of injurious interactions arising from EMF affecting devices or implants needs to be managed. Potential interactions include electromagnetic interference, displacement, and electrostimulation or heating of adjacent tissue, depending on the device or implant and the frequency of the fields. A guidance note, which uses a risk management framework, has been developed to give generic advice in (a) risk identification--implementing procedures to identify workers with implants and to characterise EMF exposure within a workplace; (b) risk assessment--integrating the characteristics of devices, the anatomical localisation of implants, occupational hygiene data, and application of basic physics principles; and (c) risk control--advising the worker and employer regarding safety and any necessary changes to work practices, while observing privacy. PMID:18534156

Hocking, Bruce; Mild, Kjell Hansson

2008-01-01

191

Two-dimensional electromagnetic Child-Langmuir law of a short-pulse electron flow  

NASA Astrophysics Data System (ADS)

Two-dimensional electromagnetic particle-in-cell simulations were performed to study the effect of the displacement current and the self-magnetic field on the space charge limited current density or the Child-Langmuir law of a short-pulse electron flow with a propagation distance of ? and an emitting width of W from the classical regime to the relativistic regime. Numerical scaling of the two-dimensional electromagnetic Child-Langmuir law was constructed and it scales with (?/W) and (?/W)2 at the classical and relativistic regimes, respectively. Our findings reveal that the displacement current can considerably enhance the space charge limited current density as compared to the well-known two-dimensional electrostatic Child-Langmuir law even at the classical regime.

Chen, S. H.; Tai, L. C.; Liu, Y. L.; Ang, L. K.; Koh, W. S.

2011-02-01

192

Use of LHP for cooling power electronic components  

NASA Astrophysics Data System (ADS)

The paper deals with use of cooling equipment build on basis two phase thermosyphon loop. This device belongs to a group of loop heat pipe (LHP). This LHP is a two-phase device with extremely high effective thermal conductivity that utilizes the thermodynamic pressure difference to circulate fluid. It was invented in Russia in the early 1980´s. Thermosyphon loop is similar as LHP but it doesn't contain wick and circulation of the fluid using gravitation force instead of capillary pressure as it is in LHP. The work deals with the cooling insulated gate bipolar transistor with 370 W. The paper describes the course of the heat dissipation using ribbed cooler for natural convection and using fin for forced convection. The results are compared with heat dissipation through thermosyphon loop.

Smitka, M.; Malcho, M.; Nemec, P.; Kolková, Z.

2013-04-01

193

Gas-assisted evaporative cooling of high density electronic modules  

Microsoft Academic Search

Gas-assisted evaporative cooling (GAEC), its advantages in thermal packaging of microelectronics, and its implementation in a prototype high-performance computer module, are described. Attention is then turned to theoretical considerations in the flow of gas-liquid-vapor mixtures in narrow, parallel plate channels, and to the design and operation of an appropriate experimental apparatus. Next, experimental results for the wall temperature, heat-transfer coefficients,

Avram Bar-Cohen; Greg Sherwood; Marc Hodes; Gary Solbreken

1995-01-01

194

Electron Bernstein wave excitation by counterpropagating electromagnetic waves in a plasma  

SciTech Connect

Two high-power counterpropagating electromagnetic waves ({omega}{sub 1},k{sub 1}x) and ({omega}{sub 2},-k{sub 2}x) in a low-density plasma in the presence of a static magnetic field B{sub s}z, drive an electron Bernstein wave at the beat frequency {omega}={omega}{sub 1}-{omega}{sub 2} and k=(k{sub 1}+k{sub 2})x, when {omega}{approx}{omega}{sub c}<<{omega}{sub 1},{omega}{sub 2} and k{rho}{>=}1, where {omega}{sub c} is the electron cyclotron frequency and {rho} is the Larmor radius. The electromagnetic waves exert a ponderomotive force on the electrons and resonantly drive the Bernstein mode({omega},k). When the pump waves have finite z extent, the Bernstein wave has an effective k{sub z} and a component of group velocity in the direction of the magnetic field, leaking it out of the interaction region, limiting the level of the Bernstein mode. Plasma inhomogeneity also introduces convection losses. However, the electron Bernstein mode potential could still be significantly greater than the ponderomotive potential.

Kumar, Asheel; Tripathi, V.K. [Physics Department, Allahabad University, Allahabad-211002 (India)

2005-10-01

195

Observation of Electron Gas Cooling in Free Sodium Clusters  

NASA Astrophysics Data System (ADS)

Free size-selected Nan+ (n=16 250) clusters have been studied by femtosecond pump-probe photoelectron and photofragmentation spectroscopy. Thermal electron emission from the hot electron gas was used to monitor the energy transfer from the electronic system to lattice vibrations. The electron-phonon coupling constants determined for the different sizes can be described by the radius dependent function g(R)=(2.3+114Å2/R2)×1016W/m3K. No strong quantum size effect was observed even for the smallest cluster size.

Maier, M.; Wrigge, G.; Hoffmann, M. Astruc; Didier, P.; Issendorff, B. V.

2006-03-01

196

Fabrication of a diffusion cooled superconducting hot electron bolometer for THz mixing applications  

Microsoft Academic Search

Recent interest in bolometers for heterodyne mixing applications has prompted development of microbridges which are small enough to allow electron diffusion to dominate over electron-phonon interaction as a cooling mechanism. Prior results at 533 GHz have demonstrated several GHz intermediate frequency (IF) bandwidth. Here we describe our processing method in which the bolometer element is a 10 nm thin film

Bruce Bumble; Henry G. LeDuc

1997-01-01

197

The Precise Synchrotron Spectrum of Fast Cooling Electrons and the GRB Prompt Emission  

Microsoft Academic Search

It is believed commonly that the synchrotron emission of electrons within the shocked region is the leading radiation mechanism for GRB prompt emission. However, the theoretical prediction has not been conformed to observed results well. We confirm that the electrons within the shocked regions fast cool due to radiation losses on a time scale much shorter than the dynamical time

Z. Mao; P. B. Yang

2009-01-01

198

Piezoelectric ceramic bimorph coupled to thin metal plate as cooling fan for electronic devices  

Microsoft Academic Search

Several types of piezoelectric fans for cooling electronic devices were constructed and tested at 60 Hz, 110 V and 220 V, respectively. The aim of the work is to investigate the possibility of replacing the rotary type of fan in some noise-sensitive electronic devices. Different vibrating metal plates were tested and analyzed theoretically. It is found that the resonant frequency

Ju Hyun Yoo; Jae Il Hong; Wenwn Cao

2000-01-01

199

Development of a Compact Electron Beam Ion Source Cooled with Liquid Nitrogen  

Microsoft Academic Search

A small-sized EBIS type ion source (mini-EBIS) for production of highly charged ions has been developed. The whole system, namely, the electron gun, ion drift tube, electron collector, ion extraction lens and liquid nitrogen reservoir containing solenoid coil is housed in a vacuum envelope, 150 mmphi in diameter and 500 mm in length. The idea of cooling the solenoid to

Kazuhiko Okuno

1989-01-01

200

Proof-of-Principle Experiment for FEL-based Coherent Electron Cooling  

SciTech Connect

Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders*. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using one of JLab’s SRF cryo-modules. In this paper, we describe the experimental setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC.

Litvinenko, V; Bengtsson, J; Fedotov, A V; Hao, Y; Kayran, D; Mahler, G J; Meng, W; Roser, T; Sheehy, B; Than, R; Tuozzolo, J E; Wang, G; Webb, S D; Yakimenko, V; Bell, G I; Bruhwiler, D L; Schwartz, B T; Hutton, A; Krafft, G A; Poelker, M

2011-03-01

201

The Precise Synchrotron Spectrum of Fast Cooling Electrons and the GRB Prompt Emission  

NASA Astrophysics Data System (ADS)

It is believed commonly that the synchrotron emission of electrons within the shocked region is the leading radiation mechanism for GRB prompt emission. However, the theoretical prediction has not been conformed to observed results well. We confirm that the electrons within the shocked regions fast cool due to radiation losses on a time scale much shorter than the dynamical time of the system. It is also indicated that the synchrotron spectrum of fast cooling electrons obtained in the past is a rough results. We show the precise synchrotron spectrum of fast cooling electrons by numerical calculating and thereby explain the observed distribution of GRB low-energy spectrum index α reasonably. In addition, we fit the correlation between α and peak energy Ep of spectrum.

Mao, Z.; Yang, P. B.

2009-04-01

202

Electron kinetic effects in atmosphere breakdown by an intense electromagnetic pulse.  

PubMed

A physical model is proposed for description of electron kinetics driven by a powerful electromagnetic pulse in the Earth's atmosphere. The model is based on a numerical solution to the Boltzmann kinetic equation for two groups of electrons. Slow electrons (with energies below a few keV) are described in a two-term approximation assuming a weak anisotropy of the electron distribution function. Fast electrons (with energies above a few keV) are described by a modified macroparticle method, taking into account the electron acceleration in the electric field, energy losses in the continuous deceleration approximation, and the multiple pitch angle scattering. The model is applied to a problem of the electric discharge in a nitrogen, which is preionized by an external gamma-ray source. It is shown that the runaway electrons have an important effect on the energy distribution of free electrons, and on the avalanche ionization rate. This mechanism might explain the observation of multiple lightning discharges observed in the Ivy-Mike thermonuclear test in the early 1950's. PMID:11970682

Solovyev, A A; Terekhin, V A; Tikhonchuk, V T; Altgilbers, L L

1999-12-01

203

Electron kinetic effects in atmosphere breakdown by an intense electromagnetic pulse  

NASA Astrophysics Data System (ADS)

A physical model is proposed for description of electron kinetics driven by a powerful electromagnetic pulse in the Earth's atmosphere. The model is based on a numerical solution to the Boltzmann kinetic equation for two groups of electrons. Slow electrons (with energies below a few keV) are described in a two-term approximation assuming a weak anisotropy of the electron distribution function. Fast electrons (with energies above a few keV) are described by a modified macroparticle method, taking into account the electron acceleration in the electric field, energy losses in the continuous deceleration approximation, and the multiple pitch angle scattering. The model is applied to a problem of the electric discharge in a nitrogen, which is preionized by an external gamma-ray source. It is shown that the runaway electrons have an important effect on the energy distribution of free electrons, and on the avalanche ionization rate. This mechanism might explain the observation of multiple lightning discharges observed in the Ivy-Mike thermonuclear test in the early 1950's.

Solovyev, A. A.; Terekhin, V. A.; Tikhonchuk, V. T.; Altgilbers, L. L.

1999-12-01

204

Nonlinear interaction of intense electromagnetic waves with a magnetoactive electron-positron-ion plasma  

NASA Astrophysics Data System (ADS)

The nonlinear coupling between circularly polarized electromagnetic (CPEM) waves and acoustic-like waves in a magnetoactive electron-positron-ion (e-p-i) plasma is studied, taking into account the relativistic motion of electrons and positrons. The possibility of modulational instability and its growth rate as well as the envelope soliton formation and its characteristics in such plasmas are investigated. It is found that the growth rate of modulation instability increases in the case that ?c/?<1 (?c and ? are the electron gyrofrequency and the CPEM wave frequency, respectively) and decreases in the case that ?c/?>1. It is also shown that in a magnetoactive e-p-i plasma, the width of bright soliton increases/decreases in case of (?c/?)<1/(?c/?)>1 by increasing the magnetic field strength.

Khorashadizadeh, S. M.; Rastbood, E.; Zeinaddini Meymand, H.; Niknam, A. R.

2013-08-01

205

Evaporative cooling of highly charged ions in EBIT (Electron Beam Ion Trap): An experimental realization  

SciTech Connect

Both the total number and trapping lifetime of near-neon-like gold ions held in an electron beam ion trap have been greatly increased by a process of 'evaporative cooling'. A continuous flow of low-charge-state ions into the trap cools the high-charge-state ions in the trap. Preliminary experimental results using titanium ions as a coolant are presented. 8 refs., 6 figs., 2 tabs.

Schneider, M.B.; Levine, M.A.; Bennett, C.L.; Henderson, J.R.; Knapp, D.A.; Marrs, R.E.

1988-12-01

206

A Unique Approach to Power Electronics and Motor Cooling in a Hybrid Electric Vehicle Environment  

Microsoft Academic Search

An innovative system for cooling the power electronics of hybrid electric vehicles is presented. This system uses a typical automotive refrigerant R-134a (1,1,1,2 tetrafluoroethane) as the cooling fluid in a system that can be used as either part of the existing vehicle passenger air conditioning system or separately and independently of the existing air conditioner. Because of the design characteristics,

Curtis William Ayers; J. C. Conklin; J. S. Hsu; K. T. Lowe

2007-01-01

207

Reflection of electromagnetic radiation from plasma with an anisotropic electron velocity distribution  

NASA Astrophysics Data System (ADS)

The reflection of a test electromagnetic pulse from the plasma formed as a result of tunnel ionization of atoms in the field of a circularly polarized high-power radiation pulse is analyzed using the kinetic approach to describe electron motion. It is shown that the reflected pulse is significantly amplified due to the development of Weibel instability. The amplification efficiency is determined by the maximum value of the instability growth rate, which depends on the degree of anisotropy of the photoelectron distribution function.

Vagin, K. Yu.; Uryupin, S. A.

2013-08-01

208

The Hopf's limiting cycle -- A method to measure the electron cooling force  

SciTech Connect

The longitudinal phase space structure of protons in the presence of an electron drag force is studied. Depending on the relative difference in average proton velocity and electron velocity, the fixed point near the center of the phase space can be stable or unstable. When it is unstable, a stable Hopf's limit cycle exists. By measuring the appearance and size of the Hopf's limit cycle, the electron cooling force can be deduced.

King-Yuen Ng

2002-09-30

209

Improved thermoelectrically cooled X/?-ray detectors and electronics  

NASA Astrophysics Data System (ADS)

An improved compact, high-resolution spectroscopy system has been developed in which Si-PIN or Cd1-xZnxTe radiation detectors and certain preamplifier components are mounted on a thermoelectric cooler. This system combines very high-energy resolution with the convenience of room temperature operation, since the cooling is transparent to the user. Several recent developments have considerably improved performance, resulting in dramatic improvements in both the energy resolution and sensitivity of this commercially available system. In addition, a complete portable spectroscopy system and a very low-noise, general-purpose laboratory preamplifier are now available. These improvements, the measured performance, and field applications of these systems will be discussed.

Redus, R. H.; Huber, A. C.; Pantazis, J. A.

2001-02-01

210

Cooling of particle beams.  

National Technical Information Service (NTIS)

A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling wi...

A. M. Sessler

1994-01-01

211

PM2D code simulation of electronic dynamics and electro-magnetic fields generation by ultra-short laser pulses interaction with matter  

Microsoft Academic Search

The results of numerical simulation of fast electrons motion and generated electro-magnetic fields at the picosecond pulse laser interaction with flat target are presented. The calculations were performed with PM2D code, where relativistic equation of electron motion joint with Maxwell equations is solved by particle method in cells. The efficiency of fast electrons energy conversion to the transverse electromagnetic wave

I. A. Litvinenko; V. A. Lykov

1997-01-01

212

Electromagnetic surface modes in a magnetized quantum electron-hole plasma  

SciTech Connect

The propagation of surface electromagnetic waves along a uniform magnetic field is studied in a quantum electron-hole semiconductor plasma. A forward propagating mode is found by including the effect of quantum tunneling. In the classical limit (({h_bar}/2{pi}){yields}0), one of the low-frequency modes found is similar to an experimentally observed one in n-type InSb at room temperature. The surface modes are shown to be significantly modified in the case of high-conductivity semiconductor plasmas where electrons and holes may be degenerate. The effects of the external magnetic field and the quantum tunneling on the surface wave modes are discussed.

Misra, A. P. [Department of Physics, Umeaa University, SE-901 87 Umeaa (Sweden)

2011-05-15

213

Neutrino pair emission off electrons in a strong electromagnetic wave field  

SciTech Connect

The emission of {nu}{nu} pairs off electrons in a polarized ultraintense electromagnetic (e.g., laser) wave field is analyzed. We elaborate on the significance of nonlinear electrodynamics effects (i.e., multiphoton processes) and the peculiarities of neutrino production. Special attention is devoted to the convergence of the reaction probabilities as a function of the number of absorbed photons. Expressions for large field intensities are provided. The asymmetry between the probabilities of electron and {mu}+{tau} neutrino production depends on initial conditions such as energy of the wave field photons and the field intensity. These findings differ from the lowest-order perturbative calculation of the reaction {gamma}+e{yields}e{sup '}+{nu}{nu}.

Titov, A. I. [Forschungzentrum Dresden-Rossendorf, 01314 Dresden (Germany); Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna 141980 (Russian Federation); Institute of Laser Engineering, Yamada-oka, Suita, Osaka 565-0871 (Japan); Kaempfer, B. [Forschungzentrum Dresden-Rossendorf, 01314 Dresden (Germany); Institut fuer Theoretische Physik, TU Dresden, 01062 Dresden (Germany); Takabe, H. [Institute of Laser Engineering, Yamada-oka, Suita, Osaka 565-0871 (Japan); Hosaka, A. [Research Center of Nuclear Physics, 10-1 Mihogaoka Ibaraki, 567-0047 Osaka (Japan)

2011-03-01

214

Electromagnetic Interference and Electromagnetic Compatibility Test Technology  

Microsoft Academic Search

With the extensive application of electronic equipment, issues from electromagnetic compatibility caused by electromagnetic interference will directly affect the normal operation of the system or equipment. In this paper, the electromagnetic interference on the basis of research and analysis the two typical interference source-- the inverter and microwave ovens, to discuss the mechanism and performance of electromagnetic and microwave radiation,

Feng Lv; Hua Zhao; Wenxia Du; Huilong Jin

2010-01-01

215

A room temperature, or moderately cooled, fast THz semiconductor hot electron bolometer  

Microsoft Academic Search

A fast THz bolometer is proposed in which, unlike the conventional thermal one, electromagnetic radiation heats only electrons in a narrow gap semiconductor without its lattice inertial heating. Under determined conditions, this heating changes generation-recombination processes that cause the carrier number to decrease and the semiconductor resistance to rise. The Hg0.8Cd0.2Te detector noise equivalent power in the range of 77-300

V. Dobrovolsky; F. Sizov

2007-01-01

216

Comment on ''Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding'' [Phys. Plasmas 17, 093103 (2010)  

SciTech Connect

The chaotic electron dynamics in a free-electron laser with electromagnetic-wave wiggler and ion-channel has been recently reported by A. Taghavi et al.[Phys. Plasmas 17, 093103 (2010)]. We comment on the authors use of a set of initial condition that is not correct based on the dispersion relation and steady-state orbits.

Nasr, N.; Hasanbeigi, A. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

2011-05-15

217

Comment on ``Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding'' [Phys. Plasmas 17, 093103 (2010)  

NASA Astrophysics Data System (ADS)

The chaotic electron dynamics in a free-electron laser with electromagnetic-wave wiggler and ion-channel has been recently reported by A. Taghavi et al. [Phys. Plasmas 17, 093103 (2010)]. We comment on the authors use of a set of initial condition that is not correct based on the dispersion relation and steady-state orbits.

Nasr, N.; Hasanbeigi, A.

2011-05-01

218

The integration of liquid cryogen cooling and cryocoolers with superconducting electronic systems  

NASA Astrophysics Data System (ADS)

The need for cryogenic cooling has been a critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of many of the superconducting circuits is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a serious disadvantage. This paper discusses the process of refrigerating superconducting devices with cryogenic liquids and small cryocoolers. Three types of cryocoolers are compared for vibration, efficiency and reliability. The connection of a cryocooler to the load is discussed. A comparison of using flexible copper straps to carry the heat load and using heat pipe is shown. The type of instrumentation needed for monitoring and controlling the cooling is discussed.

Green, Michael A.

2003-12-01

219

Experimental investigation of the effectiveness of flow-through modules for electronics cooling  

Microsoft Academic Search

The heat transfer characteristics and performance capabilities of a liquid flow-through module for electronics cooling were investigated experimentally using the Standard Electronics Module, format 'E' (SEM-E) size module. Brayco Micronic 889, a dielectric polyalphaolefin, was tested as the coolant. One surface of the flow-through module was populated with six etched foil heaters placed on the module over the fluid flow

William G. Plott

1994-01-01

220

Spectroscopy and dynamics of jet-cooled hydrazines and ammonia. II. Electron-impact dissociative ionization  

Microsoft Academic Search

Dissociative-ionization cross sections, fragment appearance potentials, and fragment kinetic energies were measured for electron-impact excitation of jet-cooled NH3, hydrazine (N2H4), and monomethyl hydrazine (MMH) over an energy range of 10–270 eV. A data base of 35 parent and fragment ions is reported. All measurements were made in a crossed electron–molecular beam apparatus using pulsed extraction and time-of-flight mass detection to

Jack A. Syage

1992-01-01

221

Spectroscopy and dynamics of jet-cooled hydrazines and ammonia. II - Electron-impact dissociative ionization  

Microsoft Academic Search

A crossed electron molecular beam apparatus is presently used to measure dissociative-ionization cross sections, fragment appearance potentials, and fragment kinetic energies of the electron-impact excitation of jet-cooled NH3, hydrazine, and monomethyl hydrazine (MMH) over the 10-270 eV energy range. The kinetic energies for hydrazine and MMH fragment ions at similar excitation energies are typically much lower than those for NH3,

Jack A. Syage

1992-01-01

222

Anomalous Temperature Reduction of Electron-Cooled Heavy Ion Beams in the Storage Ring ESR  

Microsoft Academic Search

Experiments with low intensity beams of electron-cooled highly charged ions in the storage ring ESR have been performed. The momentum spread which was analyzed by Schottky noise detection shows a considerable reduction when the number of stored ions is reduced below several thousands. This indicates that intrabeam scattering which determines the momentum spread for higher beam intensities is strongly suppressed.

Markus Steck; Karl Beckert; H. Eickhoff; B. Franzke; F. Nolden; H. Reich; B. Schlitt; T. Winkler

1996-01-01

223

Electron Microscope Studies of Minerals: Phase Boundaries in an Extremely Slowly Cooled Clinopyroxene (Augite)  

Microsoft Academic Search

High resolution electron microscopy has been used to study the nature of exsolution lamellae that developed during extremely slow and prolonged cooling and depressurization of an aluminium rich augite (high Ca clinopyroxene) taken from a layer of garnet-augite rich gneiss that outcrops on the north side of Scourie Bay, Sutherland, northwest Scotland. The parent clinopyroxene structure evolved with an average

E. Sian Crawford; Janet A. Folkes; J. O. Williams; A. C. Barnicoat; M. J. O'Hara

1983-01-01

224

MINIATURE PULSE TUBE FOR THE COOLING OF ELECTRONIC DEVICES: FUNCTIONING PRINCIPLES AND PRACTICAL MODELING  

Microsoft Academic Search

The miniaturization of refrigerating systems represents a very current scientific and technical challenge to improve the performances of numerous electronic components. This work presents a global approach to the problem and suggests studying the cooling by means of small channels filled with an oscillating gas: the double inlet pulse tube refrigerator (DIPTR). A great level of miniaturization based on the

Philippe Nika; Yannick Bailly; Michel De Labachelerie; Jean Claude Jeannot; Jacques De Lallee

2004-01-01

225

A capillary-pumped loop (CPL) with microcone-shaped capillary structure for cooling electronic devices  

Microsoft Academic Search

A MEMS-based integrated capillary-pumped loop (CPL), which can be used for cooling electronic devices such as the CPU of a personal computer or notebook, was developed. The CPL consists of an evaporator and condenser both with the same size of 30 mm × 30 mm × 5.15 mm, which were fabricated using two layers of glass wafer and one layer

Jung-Yeul Jung; Hoo-Suk Oh; Dae Keun Lee; Kyong Bin Choi; Sang Keun Dong; Ho-Young Kwak

2008-01-01

226

Heat transfer studies of a flow-through module for electronics cooling. Master`s thesis  

Microsoft Academic Search

The thermal performance characteristics of an electronics cooling Liquid Flow Through Module (FTM) were experimentally investigated. Different sets of experiments were conducted for each side of the FTM. A synthetic dielectric polyalphaolefin type coolant, Brayco Micronic 889, was used. Six etched foil type heaters were attached to one side of the FTM over the fluid flow path while three heaters

Yeniceri

1995-01-01

227

Antiproton and Electron Plasma Behavior and its Control for Production of Ultraslow Antiproton Beams  

SciTech Connect

For the production of ultraslow antiproton beams, decelerated antiprotons were captured in an electro-magnetic trap and cooled by collisions with preloaded electrons. This electron cooling feature was non-destructively monitored by measurement of electrostatic oscillations of the electron plasma. The radial distribution of the plasma was controlled for efficient cooling and extraction by utilizing rotating wall field technique.

Kuroda, N.; Shibata, M.; Mohri, A. [RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Torii, H.A.; Nagata, Y.; Komaki, K. [Institute of Physics, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 (Japan); Barna, D. [KFKI Research Institute of Particle and Nuclear Physics, H-1525 Budapest (Hungary); Hori, M. [CERN, CH-1211 Geneva (Switzerland); Yamazaki, Y. [RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Institute of Physics, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 (Japan)

2005-10-26

228

Effect of the field gradient of an intense electromagnetic beam on electrons and atoms  

SciTech Connect

It is demonstrated that the transverse inhomogeneity of a strong electromagnetic ray can exert a strong effect on electrons and atoms of a medium. Thus, if the wave frequency exceeds the proper frequency the electron oscillations (in a plasma or in atoms), the electrons or atoms will be forced-out of the ray field. At sub-resonance frequencies the particles will be pulled in, the force being especially large at resonance. As a result of this effect a rarefication or compression may occur in the ray or in the focus of the radiation; moreover the pressure gradient near the hole connecting the evacuated vessel with the atmosphere may be maintained and a channel conducting charged particles may be created in the medium. It is mentioned that a strong thermal, ionizing and separating effect of ray on the medium can be used for setting up wave guide conditions of propagation and for eliminating divergency of the ray (self-focusing). It is noted that hollow rays may ensure directed flow and ejection of the plasma along the ray axis for plasma transport and creation of plasma current conductors. The possibilities of acceleration and heating of plasma electrons by a modulated ray are indicated.

Askaryan, G.A.

1991-01-02

229

Enhanced nonlinear interaction of powerful electromagnetic waves with ionospheric plasma near the second electron gyroharmonic  

NASA Astrophysics Data System (ADS)

Plasma experiments in which a powerful electromagnetic pump wave is transmitted into the ionosphere from the ground give access to a rich range of phenomena, including gyroharmonic effects when the pump frequency is near an harmonic of the ionospheric electron gyrofrequency. For pump frequencies close to the second gyroharmonic, experiments show a strong enhancement, as observed in radar scatter from pump-induced geomagnetic field-aligned density striations and optical emissions. This is in contrast to the case at the third harmonic and higher at which most of the effects are instead suppressed. We show theoretically that electrostatic oscillations can be localized in density inhomogeneities associated with small scale striations. The localized field is a mixture of the electron Bernstein and upper hybrid modes when the pump frequency is near the second gyroharmonic. The coupling of the modes is enabled by a symmetry feature of the linear electron Bernstein and upper hybrid dispersion properties that occur only near the second gyroharmonic. Electron acceleration inside the density inhomogeneities by localized azimuthal electrostatic oscillations is more efficient near the second gyroharmonic than at higher frequencies, consistent with the observed enhancements.

Istomin, Ya. N.; Leyser, T. B.

2013-05-01

230

Dispersion characteristics of the electromagnetic waves in a relativistic electron beam guided by the ion channel  

SciTech Connect

In this article, the dispersion characteristics of the paraxial (near axis) electromagnetic (EM) waves in a relativistic electron beam guided by the ion channel are investigated. Equilibrium fields such as ion-channel electrostatic field and self-fields of relativistic electron beam are included in this formalism. In accordance with the equilibrium field structure, radial and azimuthal waves are selected as base vectors for EM waves. It is shown that the dispersion of the radially polarized EM and space charge waves are influenced by the equilibrium fields, but azimuthally polarized wave remain unaffected. In some wave number domains, the radially polarized EM and fast space charge waves are coupled. In these regions, instability is analyzed as a function of equilibrium structure. It is shown that the total equilibrium radial force due to the ion channel and electron beam and also relativistic effect play a key role in the coupling of the radially polarized EM wave and space charge wave. Furthermore, some asymptotic behaviors such as weak and strong ion channel, nonrelativistic case and cutoff frequencies are discussed. This instability could be used as an amplification mechanism for radially polarized EM waves in a beam-plasma system where a relativistic electron beam is guided by the ion channel.

Mirzanejhad, Saeed; Sohbatzadeh, Farshad; Ghasemi, Maede; Sedaghat, Zeinab; Mahdian, Zeinab [Department of Physics, Faculty of Science, Mazandaran University, 47416-95447 Babolsar (Iran, Islamic Republic of)

2010-05-15

231

Simulation of electron cooling and intrabeam scattering processes of a heavy ion beam in HIRFL-CSR  

Microsoft Academic Search

This paper is devoted to the simulation of electron cooling and intrabeam scattering processes of a heavy ion beam in the proposed HIRFL-CSR, according to the analytical cooling force formulae and the intrabeam scattering growth rate expressions. Some important effects like the betatron and synchrotron oscillations, and space charge effect of the electron beam have been considered. Time evolution of

Y. N Rao; T. Katayama

1997-01-01

232

Micromachined cryogenic cooler for cooling electronic devices down to 30 K  

NASA Astrophysics Data System (ADS)

Cryogenic temperatures are required for improving the performance of electronic devices and for operating superconducting sensors and circuits. The broad implementation of cooling these devices has long been constrained by the availability of reliable and low cost cryocoolers. After the successful development of single-stage micromachined coolers able to cool to 100 K, we now present a micromachined two-stage microcooler that cools down to 30 K from an ambient temperature of 295 K. The first stage of the microcooler operates at about 94 K with nitrogen gas and pre-cools the second stage operating with hydrogen gas. The microcooler is made from just three glass wafers and operates with modest high-pressure gases and without moving parts facilitating high yield fabrication of these microcoolers. We have successfully cooled a YBCO film through its superconducting transition state to demonstrate a load on the microcooler at cryogenic temperatures. This work could expedite the application of superconducting and electronic sensors and detectors among others in medical and space applications.

Cao, H. S.; Holland, H. J.; Vermeer, C. H.; Vanapalli, S.; Lerou, P. P. P. M.; Blom, M.; ter Brake, H. J. M.

2013-02-01

233

The interaction of electromagnetic wave and plasma wave in an electron beam-ion channel system  

SciTech Connect

The features of the waves and the instability induced by the interaction of electromagnetic (EM) wave with plasma wave in the electron beam-ion channel system are studied. Characteristics of waves in the system are displayed through the dispersion relation and two kinds of EM instabilities are found. The first one is excited by the interaction of the fast plasma wave and the forward EM wave, and the other one is induced by the coupling of the fast plasma wave and the backward EM wave, the numerical results show that this is caused by the virtual cathode oscillation. The conditions of these EM instabilities are given and the related physical mechanisms have been discussed in detail.

Su, D.; Tang, C. J. [Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu, 610064 (China)

2011-02-15

234

New method of modeling electronic circuits coupled with 3D electromagnetic finite element models  

NASA Astrophysics Data System (ADS)

New zero-dimensional or scalar electromagnetic finite elements taht have the time integral of electric scalar potential as their nodal variable are presented. There are three zero-dimensional element types, representing resistors, capacitors, and inductors. These elements can be easily combined with two- or three-dimensional elements, with three components of magnetic vector potential and the time integral of electric scalar potential as nodal variables. Constant current sources are directly modeled by inhomogeneous Neumann excitations, and constant voltage sources are modeled by use of Norton's theorem. By the addition of dependent current and voltage sources, electronic circuits can be modeled. Example finite-element analyses include an R-L circuit, a transistor circuit driving a wire loop modeled with three-dimensional finite elements, and a circuit impedance on the secondary of a saturable three-dimensional transformer model.

Brauer, J. R.; MacNeal, B. E.; Larkin, L. A.; Overbye, V. D.

1991-09-01

235

Precise Synchrotron Radiation Spectrum of Fast-cooling Electrons and the Prompt GRB Emission  

NASA Astrophysics Data System (ADS)

It is generally believed that the synchrotron radiation of electrons from the internal shock is the main radiation mechanism of the prompt GRB (gamma-ray burst) emission. However, what this model predicts can not explain observations well. In this paper, we confirm that electrons are quickly cooled due to radiation losses and also point out that the synchrotron radiation spectrum presented in previous papers is a relatively rough estimation. We get the precise synchrotron radiation spectrum of fast-cooling electrons by carrying out a numerical calculation, and thereby reasonably explain the observed distribution of low-energy spectral index (?) of long GRBs based on a unified model. In addition, we fit the correlation between ? and the peak energy of the ?F? spectrum ( Ep).

Mao, Zhu; Yang, Pi-Bo

2009-10-01

236

Design and Fabrication of Achromatic Bend for Medium Energy Electron Cooling at Fermilab  

NASA Astrophysics Data System (ADS)

The use of an achromatic bend for a medium energy electron cooling beamline in the Main Injector Recycler ring at Fermilab is required to ensure a stable beam position. This first order 180^o achromat consist of two 90^o dipoles with a 60.96 cm bend radius, a central dispersion-suppressing quadrupole flanked symmetrically by a weak solenoid and an air-core cos(2?) quadrupole. The mechanical design, specification, and technique of fabrication for each achromatic bend component is discussed. Each of the air cooled mechanical designs are simple yet precise in terms of construction technique. The results of magnetic field measurements are also presented.

McGee, M. W.; Hurh, P. G.; Bertsche, K. J.

1997-05-01

237

Warm plasma effects on electromagnetic ion cyclotron wave MeV electron interactions in the magnetosphere  

NASA Astrophysics Data System (ADS)

The full kinetic linear dispersion relation in a warm plasma with He+ and O+ ions is used to estimate the minimum resonant electron energies required for resonant scattering of relativistic electrons by electromagnetic ion cyclotron waves. We find two significant differences from the cold-plasma approximation: (1) waves can be excited inside the stop bands and at ion gyrofrequencies for relatively small wave numbers k < ?p/vA and (2) short wavelengths with k > ?p/vA experience strong cyclotron damping. We show that, in general, minimum resonant energy of electrons Emin depends only on the wave number k, magnetic field strength B, and plasma mass density ? and depends on the wave frequency ? only implicitly, via the dispersion relation. Formulae for Emin as function of ? based on cold-plasma approximation predict the lowest energy loss where ? ? ?He+, since in this approximation k ? ? at these frequencies. We show this inference is incorrect and that kinetic effects mean that the ion gyrofrequencies are no longer necessarily preferential for low energy loss. The lowest values of Emin are obtained where the dispersion supports the largest wave numbers k and in the regions of the largest mass densities ? and the lowest magnetic fields B. For realistic magnetospheric conditions Emin ˜ 2 MeV and can only drop to ˜500 keV inside dense plasmaspheric plumes, with plasma density of the order of 500 cm-3, or during plasmaspheric expansions to high L shells (L ˜ 7).

Silin, I.; Mann, I. R.; Sydora, R. D.; Summers, D.; Mace, R. L.

2011-05-01

238

Observation of electron plasma waves inside large amplitude electromagnetic pulses in a temporally growing plasma  

SciTech Connect

Observation of electron plasma waves excited inside high power ({approx}10 kW) short pulse ({approx}20 {mu}s) electromagnetic (em) waves interacting with a gaseous medium (argon) in the pressure range 0.2-2.5 mTorr is reported. The waves have long wavelength ({approx}13 cm) and get damped at time scales slower ({approx}3 {mu}s) than the plasma period (0.1-0.3 {mu}s), the energy conveyed to the medium lead to intense ionization (ion density n{sub i} {approx} 10{sup 11} cm{sup -3} and electron temperature T{sub e} {approx} 6-8 eV) and rapid growth of the plasma ({approx}10{sup 5} s{sup -1}) beyond the waves. Time frequency analysis of the generated oscillations indicate the presence of two principal frequencies centered around 3.8 MHz and 13.0 MHz with a spread {Delta}f {approx} 4 MHz, representing primarily two population of electrons in the plasma wave. The experimental results are in reasonable agreement with a model that considers spatiotemporal forces of the em wave on the medium, space charges and diffusion.

Pandey, Shail; Bhattacharjee, Sudeep; Sahu, Debaprasad [Department of Physics, Indian Institute of Technology, Kanpur-208016 (India)

2012-01-15

239

An Electromagnetic Spectrum for Millennial Students: Teaching Light, Color, Energy, and Frequency Using the Electronic Devices of Our Time  

ERIC Educational Resources Information Center

In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum using diagrams and examples that incorporate technological advances and electronic devices of our…

Murphy, Maureen Kendrick

2010-01-01

240

Proof-of-principle experiment for FEL-based coherent electron cooling  

SciTech Connect

Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.

Litvinenko, V.N.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; Fedotov, A.; Hao, Y.; Kayran, D.; Mahler, G.; Marusic, A.; Meng, W.; McIntyre, G.; Minty, M.; Ptitsyn, V.; Pinayev, I.; Rao, T.; Roser, T.; Sheehy, B.; Tepikian, S.; Than, Y.; Trbojevic, D.; Tuozzolo, J.; Wang, G.; Yakimenko, V.; Poelker, M.; Hutton, A.; Kraft, G.; Rimmer, R.; Bruhwiler, D.L.; Abell, D.T.; Nieter, C.; Ranjbar, V.; Schwartz, B.T.; Vobly, P.; Kholopov, M.; Shevchenko, O.; Mcintosh, P.; Wheelhouse, A.

2011-08-21

241

Cooling Rates for Relativistic Electrons Undergoing Compton Scattering in Strong Magnetic Fields  

NASA Astrophysics Data System (ADS)

For inner magnetospheric models of hard X-ray and gamma-ray emission in high-field pulsars and magnetars, resonant Compton upscattering is anticipated to be the most efficient process for generating continuum radiation. This is in part due to the proximity of a hot soft photon bath from the stellar surface to putative radiation dissipation regions in the inner magnetosphere. Moreover, because the scattering process becomes resonant at the cyclotron frequency, the effective cross section exceeds the classical Thomson value by over two orders of magnitude, thereby enhancing the efficiency of continuum production and the cooling of relativistic electrons. This paper presents computations of the electron cooling rates for this process, which are needed for resonant Compton models of non-thermal radiation from such highly magnetized pulsars. The computed rates extend previous calculations of magnetic Thomson cooling to the domain of relativistic quantum effects, sampled near and above the quantum critical magnetic field of 44.13 TG. This is the first exposition of fully relativistic, quantum magnetic Compton cooling rates for electrons, and it employs both the traditional Johnson & Lippmann cross section and a newer Sokolov & Ternov (ST) formulation of Compton scattering in strong magnetic fields. Such ST formalism is formally correct for treating spin-dependent effects that are important in the cyclotron resonance and has not been addressed before in the context of cooling by Compton scattering. The QED effects are observed to profoundly lower the rates below extrapolations of the familiar magnetic Thomson results, as expected, when recoil and Klein-Nishina reductions become important.

Baring, Matthew G.; Wadiasingh, Zorawar; Gonthier, Peter L.

2011-05-01

242

Nonlinear propagation of intense electromagnetic waves in a hot electron-positron plasma  

NASA Astrophysics Data System (ADS)

The creation and annihilation of relativistically hot electron-positron (EP) pair plasmas in the presence of intense electromagnetic (EM) waves, which are not in thermal equilibrium, are studied by formulating a new plasma particle distribution functions, which are valid for both relativistic temperatures and relativistic amplitudes of the EM waves. It is found that intense EM waves in a collisionless EP plasma damp via nonlinear Landau damping. Accounting for the latter, we have obtained relativistic kinetic nonlinear Schrödinger equation (NLSE) with local and non-local nonlinearities. The NLSE depicts nonlinear Landau damping rates for intense EM waves. The damping rates are examined for dense and tenuous pair plasmas. Furthermore, we have studied the modulational instabilities of intense EM waves in the presence of nonlinear Landau damping. Our results reveal a new class of the modulational instability that is triggered by the inverse Landau damping in a relativistically hot EP plasma. Finally, we discuss localization of intense EM waves due to relativistic electron and positron mass increase in a hot pair plasma.

Chaudhary, R.; Tsintsadze, N. L.; Shukla, P. K.

2010-12-01

243

Measurements with a Diffusion-Cooled Nb Hot-Electron Bolometer Mixer at 1100 GHz  

Microsoft Academic Search

In this paper we report receiver sensitivity measurements with a diffusion-cooled niobium hot-electron bolometer around 1100 GHz. The lowest receiver noise temperature was 1670 K DSB, with approximately 40 nW of local oscillator power being dissipated in the device. The intermediate frequency bandwidth of this device, due to its short length (0.15 gm) and low normal resistance (43 a), exceeded

A. Skalare; W. R. McGrath; B. Bumble; H. Leduc

1998-01-01

244

The design of an asymmetric bionic branching channel for electronic chips cooling  

NASA Astrophysics Data System (ADS)

Inspired by the wing vein of Lepidoptera, a designment of asymmetric bionic branching channel for electronic chips cooling is developed. Lepidoptera vein D was chosen to measure the angle of first and second branch level. Based on these regular patterns, an asymmetric bionic branching channel is designed in a 35 mm × 35 mm chip. Comparing with fractal-like branching channel, it provides a stronger heat transfer capability, lower pressure drop and lower flow resistance in the experiment.

Xu, Shanglong; Qin, Jie; Guo, Wei; Fang, Kuang

2013-06-01

245

Design and Fabrication of Achromatic Bend for Medium Energy Electron Cooling at Fermilab  

Microsoft Academic Search

The use of an achromatic bend for a medium energy electron cooling beamline in the Main Injector Recycler ring at Fermilab is required to ensure a stable beam position. This first order 180^o achromat consist of two 90^o dipoles with a 60.96 cm bend radius, a central dispersion-suppressing quadrupole flanked symmetrically by a weak solenoid and an air-core cos(2theta) quadrupole.

M. W. McGee; P. G. Hurh; K. J. Bertsche

1997-01-01

246

Transient thermal and hydrodynamic model of flat heat pipe for the cooling of electronics components  

Microsoft Academic Search

The transient performance of a flat heat pipe (FHP) used to cool multiple electronics components, is presented in this paper. The fluid flows in both wick and vapor core were computed using a transient 2D hydrodynamic model (T2DHM). This model was coupled with a transient 3D thermal model (T3DTM) of the FHP wall, designed to calculate the heat transfer through

R. Sonan; S. Harmand; J. Pellé; D. Leger; M. Fakès

2008-01-01

247

Status of Proof-of-principle Experiment for Coherent Electron Cooling  

SciTech Connect

Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o'clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

Pinayev, I; Ben-Zvi, I; Bengtsson, J; Elizarov, A; Fedotov, A V; Gassner, D M; Hao, Y; Kayran, D; Litvinenko, V; Mahler, G J; Meng, W; Roser, T; Sheehy, B; Than, R; Tuozzolo, J E; Wang, G; Webb, S D; Yakimenko, V; Bell, G I; Bruhwiler, D L; Ranjbar, V H; Schwartz, B T; Hutton, A; Krafft, G A; Poelker, M; Rimmer, R A; Kholopov, M A

2012-07-01

248

Fraunhofer Diffraction of Atomic Matter Waves: Electron Transfer Studies with a Laser Cooled Target  

Microsoft Academic Search

We have constructed an apparatus combining the experimental techniques of cold target recoil ion momentum spectroscopy and a laser cooled target. We measure angle differential cross sections in Li++Na-->Li+Na+ electron transfer collisions in the keV energy regime with a momentum resolution of 0.12 a.u. yielding an order of magnitude better angular resolution than previous measurements. We resolve Fraunhofer-type diffraction patterns

M. van der Poel; C. V. Nielsen; M.-A. Gearba; N. Andersen

2001-01-01

249

Analysis of two-layered micro-channel heat sink concept in electronic cooling  

Microsoft Academic Search

In this work, a new concept for a two-layered micro-channel heat sink with counter current flow arrangement for cooling of the electronic components is proposed. The thermal performance and the temperature distribution for these types of micro channels were analyzed and a procedure for optimizing the geometrical design parameters is presented. While the power supply system of the two-layered design

Kambiz Vafai; Lu Zhu

1999-01-01

250

Photino bremsstrahlung in intense electromagnetic fields  

NASA Astrophysics Data System (ADS)

We calculate the probability for the emission of a pair of photinos by an electron moving in a background electromagnetic field. The rate of the process e -> e?~?~ is estimated at different values of the field strength and electron energies. Comparing the cooling rate of some astrophysical objects via photino bremsstrahlung with another competing energy-loss mechanism we find new constraints on the selectron massesMe~R =Me~L >= 89.4 GeV.

Kurilin, Alexander V.; Ternov, Aleksey I.

1996-02-01

251

Electronic properties of carbon nanotubes investigated by means of standard electromagnetic simulators  

NASA Astrophysics Data System (ADS)

Due to the formal analogy between Maxwell and Schrödinger equations, electromagnetic (e.m.) simulators may become a powerful numerical tool for the analysis of carrier transport in low-dimensional systems. In the following, we exploit this analogy in order to investigate the electronic properties of carbon nanotubes (CNTs). As a matter of fact, e.m. commercial solvers have reached a high degree of efficiency due to the demand of the high-speed and microwave circuit market. In this paper, we suggest applying e.m. numerical solvers to CNTs with a view to derive their main properties, such as dispersion curves and effective masses. In particular, we have used the “CST Microwave Studio,” implementing a finite element method (FEM). However, many other e.m. solvers are available, exploiting different approaches (FDTD, Method of Moment, TLM, etc.). In order to assess the validity of the approach, we have investigated an important example of band-gap distortion and splitting of degenerate states with respect to the angular momentum, due to an external electric field. The model can also be applied in order to better explain the behavior of metal-CNT contacts, representing a critical point for analysis and synthesis of nanotransistor devices.

Mencarelli, Davide; Rozzi, Tullio; Maccari, Luca; di Donato, Andrea; Farina, Marco

2007-02-01

252

A new approach to applying electromagnetic transient protection requirements to avionic and electronic equipment  

Microsoft Academic Search

Presently, separate and distinct electomagnetic (EM) transient protection requirements, test methods, and demonstrations are used for system-generated electromagnetic interference (EMI), lightning, and the nuclear electromagnetic pulse (NEMP) on Air Force aircraft. This lack of a common approach to applying EM transient protection requirements has resulted in inflated design costs and performance impacts. This paper describes a new approach to consolidate

J. C. Corbin; W. C. Webb

1983-01-01

253

Analysis of the electromagnetic fields and electron acceleration in the bubble regime of the laser-plasma interaction  

SciTech Connect

An analytical model for the electromagnetic fields in the bubble regime of the interaction of ultrahigh-intensity laser with plasma is given. The two-dimensional model is based on the results of particle-in-cell simulation and includes the bubble front region. It is used to consider the generation of dense ultrashort quasimonoenergetic high-energy electron bunches. The resulting bunch parameters agree fairly well with those from the simulation.

Xie Baisong; Wu Haicheng; Wang Hongyu; Wang Naiyan; Yu, M. Y. [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Department of Physics, Anshan Normal University, Anshan 114007 (China); Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Institut fuer Theoretische Physik I, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2007-07-15

254

Quantum theory of stimulated Cerenkov radiation of transverse electromagnetic waves by a low-density electron beam in a medium  

SciTech Connect

The quantum theory of stimulated Cerenkov radiation of transverse electromagnetic waves by an electron beam in an anisotropic medium is presented. Relativistic quantum nonlinear equations of the Cerenkov beam instability are obtained. In the linear approximation, the quantum dispersion equation is derived and the instability growth increments are determined. The nonlinear problem of the saturation of the quantum Cerenkov beam instability is solved. (cerenkov radiation)

Kuzelev, Mikhail V [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2010-01-31

255

Mixing and noise in diffusion and phonon cooled superconducting hot-electron bolometers  

NASA Astrophysics Data System (ADS)

We report a systematic, comprehensive set of measurements on the dynamics and noise processes in diffusion and phonon-cooled superconducting hot-electron bolometer mixers which will serve as ultralow noise detectors in THz heterodyne receivers. The conversion efficiency and output noise of devices of varying lengths were measured with radio frequency between 8 and 40 GHz. The devices studied consist of 100-Å-thin film Nb bridges connected to thick (1000 Å), high conductivity normal metal (Au) leads. The lengths of the devices studied range from 0.08 to 3 ?m. For devices longer than the electron-phonon interaction length Le-ph?D?e-ph, with D the diffusion constant and ?e-ph-1 the electron-phonon interaction rate, the hot electrons are cooled dominantly by the electron-phonon interaction, which in Nb is too slow for practical applications. If the device length is less than ?Le-ph(~1 ?m at 4.2 K), then out diffusion of heat into the high conductivity leads dominates the cooling process. In this limit, the intermediate frequency (IF) bandwidth is found to vary as L-2, with L the bridge length, as expected for diffusion cooling. The shortest device has an IF bandwidth greater than 6 GHz, the largest reported for a low-Tc superconducting bolometric mixer. The dominant component of the output noise decreases with frequency in the same manner as the conversion efficiency, consistent with a model based on thermal fluctuations. The noise bandwidth is larger than the gain bandwidth, and the mixer noise is low, ranging from 100 to 530 K (double sideband). The crossover from phonon dominated to diffusion dominated behavior is also demonstrated using noise thermometry measurements in the normal state. Scalar measurements of the device differential impedance in the intermediate state agree with a theoretical model which takes into account the thermal and electrical dynamics. We also present detailed comparisons with theoretical predictions of the output noise and conversion efficiency.

Burke, P. J.; Schoelkopf, R. J.; Prober, D. E.; Skalare, A.; Karasik, B. S.; Gaidis, M. C.; McGrath, W. R.; Bumble, B.; Leduc, H. G.

1999-02-01

256

Anomalous Temperature Reduction of Electron-Cooled Heavy Ion Beams in the Storage Ring ESR  

SciTech Connect

Experiments with low intensity beams of electron-cooled highly charged ions in the storage ring ESR have been performed. The momentum spread which was analyzed by Schottky noise detection shows a considerable reduction when the number of stored ions is reduced below several thousands. This indicates that intrabeam scattering which determines the momentum spread for higher beam intensities is strongly suppressed. Estimates of the plasma parameter {Gamma} support the idea of a phase transition from a gaseous phase to a liquidlike phase. {copyright} {ital 1996 The American Physical Society.}

Steck, M.; Beckert, K.; Eickhoff, H.; Franzke, B.; Nolden, F.; Reich, H.; Schlitt, B.; Winkler, T. [Gesellschaft fuer Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt (Germany)

1996-10-01

257

High-temperature (250 °C \\/ 500 °F) 19?000 rpm BLDC fan for forced air-cooling of advanced automotive power electronics  

Microsoft Academic Search

In an increasing number of application areas and industry sectors, such as the automotive, aerospace, military or oil and gas industry, a trend towards higher ambient temperature rating from 120 °C upward for electrical machines and power electronic converters can be observed. Forced air-cooling of power electronic converters offers reduced complexity of the cooling circuit compared to water-cooling. For high

Benjamin Wrzecionko; Andreas Looser; Johann W. Kolar; Michael Casey

2011-01-01

258

A Methodology for Determining the Electromagnetic Compatibility of a Seafarer System with Special Electronic Systems.  

National Technical Information Service (NTIS)

The technical effort reported herein is intended to support development of the Navy's Seafarer ELF Submarine Command and Control Communications System. It concerns the establishment of a methodology for assessment and control electromagnetic compatiblity ...

L. Valcik

1976-01-01

259

Status of proof-of-principle experiment for coherent electron cooling  

SciTech Connect

Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o'clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters. We use a dogleg to merge the electron and ion beams. The ions 'imprint' their distribution into the electron beam via a space charge density modulation. The modulation is amplified in an FEL comprised of a 7-m long helical wiggler. The ions are co-propagating with electron beam through the FEL. The ion's average velocity is matched to the group velocity of the wave-packet of e-beam density modulation in the FEL. A three-pole wiggler at the exit of the FEL tune the phase of the wave-packet so the ion with the central energy experience the maximum of the e-beam density modulation, where electric field is zero. The time-of-flight dependence on ion's provides for the electrical field caused by the density modulation to reduce energy spread of the ion beam. The used electron beam is bent off the ion path and damped.

Pinayev I.; Belomestnykh, S.; Bengtsson, J.; Ben-Zvi, I.; Elizarov, A. et al

2012-05-20

260

Experimental study of optimum spacing problem in the cooling of simulated electronic package  

NASA Astrophysics Data System (ADS)

An experimental investigation has been performed to determine the effects of different arrangements of obstacles on the cooling of simulated electronic package. The considered simulated electronic package consisted of a channel formed by two parallel plates. The bottom plate is attached with five identical electrically heated square obstacles, which are perpendicular to the mean airflow and arranged with different side-to-side distances. The experimental results show that the conventional equi-spaced arrangement might not be the optimum option and should be avoided. A better thermal performance could be obtained when the side-to-side distances between the obstacles followed a geometric series. For example, at Re=800, the highest temperature of the optimum arrangement could be reduced by 12% compare to the equi-spaced arrangement and the maximum temperature difference among the five obstacles is lower than that of equi-spaced arrangement by 32.1%.

Chen, S.; Liu, Y.; Chan, S. F.; Leung, C. W.; Chan, T. L.

261

Large Bandwidth Mixing in Diffusion-Cooled Hot-Electron Bolometers  

NASA Astrophysics Data System (ADS)

Superconducting hot-electron bolometers have been proposed as fast and sensitive heterodyne detectors for sub-millimeter wavelengths. For short microbridges, it was predicted (D.E. Prober, Appl. Phys. Lett., 62), 2119, 1993. that diffusion cooling of the electrons into the normal metal leads could lead to a reduction of the thermal time constant, ?, and allow intermediate frequency (IF) bandwidths of several GHz. We report here on microwave (10-20 GHz) measurements of mixer conversion efficiency for thin (10 nm) Nb bolometers, for IF's ranging from 30 MHz to 6 GHz. The conversion efficiency displays a single-pole roll-off with IF, due to the thermal time constant of the device. Time constants for devices of different lengths have been determined. For devices less than about 1 ?m, there is a dramatic reduction of the time constant with length, which obeys the scaling, ? ~ L^2, expected from diffusion cooling. The smallest device measured to date was only 80 nm long by 80 nm wide, and displayed a conversion efficiency of -5 dB, which was independent of intermediate frequency over the entire range (up to 6 GHz) observed. This represents the largest IF bandwidth yet obtained for such a bolometer, and is adequate for many practical applications. The expected limits for the bandwidth and possible non-ideal effects in ultra-short devices will also be discussed.

Schoelkopf, R. J.; Burke, P. J.; Prober, D. E.; Bumble, B.; Leduc, H. G.; Skalare, A.; McGrath, W. R.

1996-03-01

262

Efficient Coupling of Thermal Electron Bernstein Waves to the Ordinary Electromagnetic Mode on the National Spherical Torus Experiment (NSTX)  

SciTech Connect

Efficient coupling of thermal electron Bernstein waves (EBW) to ordinary mode (Omode) electromagnetic radiation has been measured in plasmas heated by energetic neutral beams and high harmonic fast waves in the National Spherical Torus Experiment (NSTX) [M. Ono, S. Kaye, M. Peng, et al., Proceedings 17th IAEA Fusion Energy Conference (IAEA, Vienna, Austria, 1999), Vol.3, p. 1135]. The EBW to electromagnetic mode coupling efficiency was measured to be 0.8 {+-} 0.2, compared to a numerical EBW modeling prediction of 0.65. The observation of efficient EBW coupling to O-mode, in relatively good agreement with numerical modeling, is a necessary prerequisite for implementing a proposed high power EBW current drive system on NSTX.

G. Taylor; P.C. Efthimion; B.P. LeBlanc; M.D. Carter; J.B. Caughman; J.B. Wilgen; J. Preinhaelter; R.W. Harvey; S.A. Sabbagh

2005-02-02

263

Requirements to beam emittances at photon colliders. Laser cooling of electron beams  

SciTech Connect

Linear colliders offer unique opportunity to study {gamma}{gamma},{gamma}e interactions. Using the laser backscattering method one can obtain {gamma}{gamma} and {gamma}e colliding beams with the energy and luminosity comparable to that in e{sup +}e{sup {minus}} collisions or even higher (due to absence of some beam collision effects). In order to reach ultimate parameters of photon colliders the {open_quotes}geometric{close_quotes} luminosity of initial electron beams should be higher than that in e{sup +}e{sup {minus}} collisions. In this report requirements to beam emittances at photon colliders are analyzed and a novel method of obtaining electron beams with small transverse emittances is considered: the electron beam is cooled during a head-on collision with the focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10 J) one can decrease the transverse normalized emittances by a factor of 10 per one stage. A limit on the final (after few stages) transverse emittance of the electron beam is much lower than that given by other known methods. {copyright} {ital 1997 American Institute of Physics.}

Telnov, V. [Institute of Nuclear Physics, 630090, Novosibirsk (Russia)

1997-02-01

264

MEMS-enabled thermal management of high-heat-flux devices EDIFICE: embedded droplet impingement for integrated cooling of electronics  

Microsoft Academic Search

This paper reports the development of embedded droplet impingement for integrated cooling of electronics (EDIFICE). The EDIFICE project seeks to develop an integrated droplet impingement cooling device for removing chip heat fluxes in the range 70–100 W\\/cm2, employing latent heat of vaporization of dielectric fluids (50–100 ?m droplets) to achieve these high heat removal rates. Micro-manufacturing and micro electro-mechanical systems

Cristina H. Amon; Jayathi Murthy; S. C. Yao; Sreekant Narumanchi; Chi-Fu Wu; Cheng-Chieh Hsieh

2001-01-01

265

First Measurements of the Unique Influence of Spin on the Energy Loss of Ultrarelativistic Electrons in Strong Electromagnetic Fields  

NASA Astrophysics Data System (ADS)

Although some authors have claimed that the effect is not detectable, we show experimentally for the first time that as the quantum parameter ? grows beyond 1, an increasingly large part of the hard radiation emitted arises from the spin of the electron. Results for the energy loss of electrons in the energy range 35-243 GeV incident on a W single crystal are presented. Close to the axial direction the strong electromagnetic fields induce a radiative energy loss which is significantly enhanced compared to incidence on an amorphous target. In such continuously strong fields, the radiation process is highly nonperturbative for ultrarelativistic particles and a full quantum description is needed. The remarkable effect of spin flips and the energy loss is connected to the presence of a field comparable in magnitude to the Schwinger critical field, E0 = m2c3/e?, in the rest frame of the emitting electron.

Kirsebom, K.; Mikkelsen, U.; Uggerhøj, E.; Elsener, K.; Ballestrero, S.; Sona, P.; Vilakazi, Z. Z.

2001-07-01

266

Effects of impurity seeding and charge non-neutrality on electromagnetic electron temperature gradient modes in a tokamak  

SciTech Connect

A linear theory of toroidal electromagnetic electron temperature gradient (ETG) mode is reported. The effects such as Debye shielding, impurities, magnetic flutter perturbations {delta}B{sub perpendicular} and compressible parallel magnetic field perturbations {delta}B{sub parallel} are included in a fluid model. An eigenvalue equation is derived and solved analytically in local and semilocal limits. In the nonlocal limit, the eigenvalue equations are solved numerically. A comparison is also made of the linear thresholds obtained from this simple fluid model with previous gyrokinetic simulations. It is shown that the simple fluid theory results compare well with the thresholds obtained from gyrokinetic simulations.

Tangri, Varun; Singh, Raghvendra; Kaw, Predhiman [Institute For Plasma Research, Bhat, Gandhinagar, Gujarat 382 428 (India)

2005-07-15

267

Feasibility and electromagnetic compatibility study of the ClearPEM front-end electronics for simultaneous PET-MR imaging  

NASA Astrophysics Data System (ADS)

In this work we present a first feasibility study of the ClearPEM technology for simultaneous PET-MR imaging. The mutual electromagnetic interference (EMI) effects between both systems were evaluated on a 7 T magnet by characterizing the response behavior of the ClearPEM detectors and front-end electronics to pulsed RF power and switched magnetic field gradients; and by analyzing the MR system performance degradation from noise pickup into the RF receiver chain, and from magnetic susceptibility artifacts caused by PET front-end materials.

Neves, J. A.; Bugalho, R.; Gruetter, R.; Magill, A. W.; Ortigão, C.; Silva, J. C.; Silva, R.; Varela, J.

2013-02-01

268

Pumped helium system for cooling positron and electron traps to 1.2 K  

NASA Astrophysics Data System (ADS)

Extremely precise tests of fundamental particle symmetries should be possible via laser spectroscopy of trapped antihydrogen (H¯) atoms. H¯ atoms that can be trapped must have an energy in temperature units that is below 0.5 K—the energy depth of the deepest magnetic traps that can currently be constructed with high currents and superconducting technology. The number of atoms in a Boltzmann distribution with energies lower than this trap depth depends sharply upon the temperature of the thermal distribution. For example, ten times more atoms with energies low enough to be trapped are in a thermal distribution at a temperature of 1.2 K than for a temperature of 4.2 K. To date, H¯ atoms have only been produced within traps whose electrode temperature is 4.2 K or higher. A lower temperature apparatus is desirable if usable numbers of atoms that can be trapped are to eventually be produced. This report is about the pumped helium apparatus that cooled the trap electrodes of an H¯ apparatus to 1.2 K for the first time. Significant apparatus challenges include the need to cool a 0.8 m stack of 37 trap electrodes separated by only a mm from the substantial mass of a 4.2 K Ioffe trap and the substantial mass of a 4.2 K solenoid. Access to the interior of the cold electrodes must be maintained for antiprotons, positrons, electrons and lasers.

Wrubel, J.; Gabrielse, G.; Kolthammer, W. S.; Larochelle, P.; McConnell, R.; Richerme, P.; Grzonka, D.; Oelert, W.; Sefzick, T.; Zielinski, M.; Borbely, J. S.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Müllers, A.; Walz, J.; Speck, A.

2011-06-01

269

Electromagnetic bandgap waveguide (EBG) phase shifters for low cost electronically scanned antennas (ESA)  

Microsoft Academic Search

Tunable electromagnetic bandgap (EBG) structures are used as variable surface impedance in the sidewall of waveguides to provide three generations of agile analog phase shifters for low cost ESA applications. A design methodology is discussed using a periodic unit cell approach. Three unique millimeter wave varactor diodes (heterojunction barrier varactor, Schottky varactors and flip chip Schottky varactor diode) have been

Hooman Kazemi; J. A. Higgins; Brian Herting; Hao Xin; Jim West; Jon Hacker

2007-01-01

270

OTR Measurements and Modeling of the Electron Beam Optics at the E-Cooling Facility  

NASA Astrophysics Data System (ADS)

Optics of the electron beam accelerated in the Pelletron, intended for the electron cooling of 8.9 GeV antiprotons in the Fermilab recycler storage ring, has been studied. The beam profile parameters were measured under the accelerating section using Optical Transition Radiation (OTR) monitor. The monitor employs a highly-reflective 2 inch-diameter aluminum OTR-screen with a thickness of 5 ?m and a digital CCD camera. The measurements were done in a pulse-signal mode in the beam current range of 0.03-0.8 A and at pulse durations ranging from 1 ?s to 4 ?s. Differential profiles measured in pulsed mode are compared with results obtained by modeling of the DC beam dynamics from the Pelletron cathode to the OTR monitor. The modeling was done with SAM, ULTRASAM and BEAM programs. An adjustment of the magnetic fields in the lenses of the accelerating section was done in the simulations. The simulated electron beam optics downstream of the accelerating section was in good agreement with the measurements made with pulsed beam.

Warner, A.; Burov, A.; Carlson, K.; Kazakevich, G.; Nagaitsev, S.; Prost, L.; Sutherland, M.; Tiunov, M.

2006-03-01

271

Electronic spectra of jet-cooled isoindoline: spectroscopic determination of energy difference between conformational isomers.  

PubMed

The electronic spectra of jet-cooled isoindoline between the electronic ground (S(0)) state and the pi pi(*) lowest-excited singlet state (S(1)) were observed by the fluorescence excitation and single-vibronic-level dispersed fluorescence methods. The low-frequency progression due to the puckering vibration appeared in both spectra. Analysis of dispersed spectra together with geometry optimization at the level of B3LYP/6-311+G(d) indicated the presence of conformational isomers possessing axial and equatorial N-H bonds with respect to the molecular plane. The 0-0 bands of the axial and equatorial conformers were measured at 37,022 and 36,761 cm(-1), respectively. Three common levels in the S(1) state accessible from the respective S(0)-state zero levels were observed. From their transition frequencies, the S(0)-state energy difference between the isomers was determined to be 47.7+/-0.2 cm(-1), where the axial conformer was more stable. In the S(1) state, the energy difference was 213.7+/-0.2 cm(-1), and the equatorial conformer was more stable. The cause of switching from a stable conformation upon excitation is discussed in terms of the electron conjugation between the pi(*) orbital in benzene and the lone pair orbital of nitrogen. PMID:20441277

Tanaka, Sei'ichi; Okuyama, Katsuhiko

2010-04-28

272

PM2D code simulation of electronic dynamics and electro-magnetic fields generation by ultra-short laser pulses interaction with matter  

SciTech Connect

The results of numerical simulation of fast electrons motion and generated electro-magnetic fields at the picosecond pulse laser interaction with flat target are presented. The calculations were performed with PM2D code, where relativistic equation of electron motion joint with Maxwell equations is solved by particle method in cells. The efficiency of fast electrons energy conversion to the transverse electromagnetic wave of picosecond duration can reach the value 10{sup -4} for the intensity of ultrashort laser pulse at the target 10{sup 16}-10{sup 17} W/cm{sup 2}.

Litvinenko, I. A.; Lykov, V. A. [Russian Federal Nuclear Center-VNIITF P.O. BOX 245, Snezhinsk (Chelyabinsk-70), 456770 (Russian Federation)

1997-04-15

273

High-flux monochromatic ion and electron beams based on laser-cooled atoms  

NASA Astrophysics Data System (ADS)

We propose a source for high-brightness ion and electron beams based on the ionization of an effusive atomic beam which is transversely laser cooled and compressed. The very low transverse temperature (mK range) and the relative low density of the starting atomic sample ensure excellent initial conditions for obtaining bright and monochromatic charge sources. In contrast to the standard photoionization techniques used by similar sources, we utilize field ionization of Rydberg atoms. This approach allows a substantial reduction of the required laser power and copes differently with the problems of the energy spread created during the ionization process and of the stochastic space-charge effect. Theoretical modeling and prospective ideas of this emerging technology are given.

Kime, L.; Fioretti, A.; Bruneau, Y.; Porfido, N.; Fuso, F.; Viteau, M.; Khalili, G.; Šanti?, N.; Gloter, A.; Rasser, B.; Sudraud, P.; Pillet, P.; Comparat, D.

2013-09-01

274

Design principles and applications of a cooled CCD camera for electron microscopy.  

PubMed

Cooled CCD cameras offer a number of advantages in recording electron microscope images with CCDs rather than film which include: immediate availability of the image in a digital format suitable for further computer processing, high dynamic range, excellent linearity and a high detective quantum efficiency for recording electrons. In one important respect however, film has superior properties: the spatial resolution of CCD detectors tested so far (in terms of point spread function or modulation transfer function) are inferior to film and a great deal of our effort has been spent in designing detectors with improved spatial resolution. Various instrumental contributions to spatial resolution have been analysed and in this paper we discuss the contribution of the phosphor-fibre optics system in this measurement. We have evaluated the performance of a number of detector components and parameters, e.g. different phosphors (and a scintillator), optical coupling with lens or fibre optics with various demagnification factors, to improve the detector performance. The camera described in this paper, which is based on this analysis, uses a tapered fibre optics coupling between the phosphor and the CCD and is installed on a Philips CM12 electron microscope equipped to perform cryo-microscopy. The main use of the camera so far has been in recording electron diffraction patterns from two dimensional crystals of bacteriorhodopsin--from wild type and from different trapped states during the photocycle. As one example of the type of data obtained with the CCD camera a two dimensional Fourier projection map from the trapped O-state is also included. With faster computers, it will soon be possible to undertake this type of work on an on-line basis. Also, with improvements in detector size and resolution, CCD detectors, already ideal for diffraction, will be able to compete with film in the recording of high resolution images. PMID:9889815

Faruqi, A R

1998-01-01

275

Radio-frequency electromagnetic field measurements for direct detection of electron Bernstein waves in a torus plasma  

SciTech Connect

To identify the mode-converted electron Bernstein wave (EBW) in a torus plasma directly, we have developed an interferometry system, in which a diagnostic microwave injected outside of the plasma column was directly detected with the probing antenna inserted into the plasma. In this work, plasma production and heating are achieved with 2.45 GHz, 2.5 kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10 W) separate frequency (1-2.1 GHz) microwave. Three components, i.e., two electromagnetic (toroidal and poloidal directions) and an electrostatic (if refractive index is sufficiently higher than unity, it corresponds to radial component), of ECRF electric field are simultaneously measured with three probing antennas, which are inserted into plasma. Selectivities of each component signal were checked experimentally. Excitation antennas have quite high selectivity of direction of linear polarization. As probing antennas for detecting electromagnetic components, we employed a monopole antenna with a length of 35 mm, and the separation of the poloidal (O-wave) and toroidal (X-wave) components of ECRF electric field could be available with this antenna. To detect EBW, which is an electrostatic wave, a small tip (1 mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.

Yatsuka, Eiichi; Kinjo, Kiyotake; Morikawa, Junji; Ogawa, Yuichi [Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8568 (Japan)

2009-02-15

276

FULL ELECTROMAGNETIC SIMULATION OF FREE-ELECTRON LASER AMPLIFIER PHYSICS VIA THE LORENTZ-BOOSTED FRAME APPROACH  

SciTech Connect

Numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame[1]. A particularly good example is that of short wavelength free-electron lasers (FELs) in which a high energy electron beam interacts with a static magnetic undulator. In the optimal boost frame with Lorentz factor gamma_F , the red-shifted FEL radiation and blue shifted undulator have identical wavelengths and the number of required time-steps (presuming the Courant condition applies) decreases by a factor of 2(gamma_F)**2 for fully electromagnetic simulation. We have adapted the WARP code [2]to apply this method to several FEL problems involving coherent spontaneous emission (CSE) from pre-bunched ebeams, including that in a biharmonic undulator.

Fawley, William M; Vay, Jean-Luc

2009-04-29

277

Electromagnetic Field of Microtubules: Effects on Transfer of Mass Particles and Electrons  

Microsoft Academic Search

Biological polar molecules and polymer structures with energy supply (such as microtubules in the cytoskeleton) can get excited\\u000a and generate an endogenous electromagnetic field with strong electrical component in their vicinity. The endogenous electrical\\u000a fields through action on charges, on dipoles and multipoles, and through polarization (causing dielectrophoretic effect) exert\\u000a forces and can drive charges and particles in the cell.

Ji?í Pokorný; Ji?í Hašek; František Jelínek

2005-01-01

278

Apparatus and method for detecting electromagnetic radiation using electron photoemission in a micromechanical sensor  

DOEpatents

A micromechanical sensor and method for detecting electromagnetic radiation involve producing photoelectrons from a metal surface in contact with a semiconductor. The photoelectrons are extracted into the semiconductor, which causes photo-induced bending. The resulting bending is measured, and a signal corresponding to the measured bending is generated and processed. A plurality of individual micromechanical sensors can be arranged in a two-dimensional matrix for imaging applications.

Datskos, Panagiotis G. (Knoxville, TN); Rajic, Slobodan (Knoxville, TN); Datskou, Irene C. (Knoxville, TN); Egert, Charles M. (Oak Ridge, TN)

2002-01-01

279

Low-Temperature Two-Phase Microchannel Cooling for High-Heat-Flux Thermal Management of Defense Electronics  

Microsoft Academic Search

For a given heat sink thermal resistance and ambient temperature, the temperature of an electronic device rises fairly linearly with increasing device heat flux. This relationship is especially problematic for defense electronics, where heat dissipation is projected to exceed 1000 W\\/cm2 in the near future. Direct and indirect low-temperature refrigeration cooling facilitate appreciable reduction in the temperature of both coolant

Jaeseon Lee; Issam Mudawar

2009-01-01

280

Conversion gain and fluctuation noise of phonon-cooled hot-electron bolometers in hot-spot regime  

Microsoft Academic Search

In this paper, a one-dimensional heat balance model for the hot-spot length of phonon-cooled hot-electron bolometer is set up and solved for the electron temperature profile along the bolometer bridge. A self-consistent theoretical method is presented to obtain the hot-spot length profile as a function of RF and bias heating power. This result is used to predict current-voltage characteristics. For

Harald F. Merkel; Pourya Khosropanah; Danny Wilms Floet; Pavel A. Yagoubov; Erik L. Kollberg

2000-01-01

281

Cryogenic Lens of a High-Voltage Electron Microscope with a Tape Winding, Cooled by Liquid Nitrogen.  

National Technical Information Service (NTIS)

The solenoid winding is suggested to be made of a metallic tape (copper, aluminium), cooled by liquid nitrogen, in order to increase the efficiency of lenses of a high-voltage (Usub(acc) > 1 MV) electron microscope. This design, being a compromise between...

G. A. Soldatenko

1977-01-01

282

The better box model: An analytical estimation of temperature and flow in a free convection air cooled electronics enclosure  

Microsoft Academic Search

A model is described to enable quick estimation of temperatures and air flow in electronic products that are cooled by free convection. Constituting elements are the size and shape of the box-like enclosure, internal heat dissipation, location and hydraulic resistances of inlet and exhaust vents, and of the main internal air path. The model proved to be very useful in

Wendy Luiten; Simon Kadijk

2009-01-01

283

Electromagnetic Noise Superimposed on the Electric Power Supply to Electronic Medical Equipment  

Microsoft Academic Search

The use of mobile medical electronic equipment driven at low electric power outputs has progressed rapidly in recent years. Voltage change and noise superimposed on the power supply could create obstacles to the operation of medical electronic equipment. We observed the quality of the power supply of medical electronic equipment in a university hospital, and found approximately 5% distortion on

Eisuke Hanada; Kyoko Takano; Kenji Kodama

2003-01-01

284

Electromagnetic simulation of electronic packaging designs (95-ERP-003). 1995 LDRD final report  

SciTech Connect

The primary focus of the project summarized in this report has been to evaluate the performance of the 3D, time-domain electromagnetic code DS13D in the simulation of structures used in microwave microelectronics circuits. We`ve adopted two test cases, coaxial and stripline transmission lines, for which well-known results are available so that results obtained with DS13D could be easily and accurately checked. Our goals have been three-fold: (1) To develop specialized mode-launching capabilities for single-mode signals typically found in test geometries and the diagnostics necessary to evaluate the performance of the code in modeling the propagation of those signals. (2) To analyze the effect of different zoning schemes on the accuracy with which the code models the propagation of signals through the geometries by checking against known analytic results and calculations performed with other codes. (3) To examine the effect of code modifications aimed at enhancing the accuracy of the simulations. The calculated transmission line impedance was chosen as the primary means of evaluating code performance. Since the lowest-order propagating modes for the test cases were transverse electromagnetic (TEM) modes, the computation of impedance was reasonably straightforward. Both time- and frequency-domain values (the latter obtained from the code output by post-processing with a discrete Fourier transform) were obtained and compared.

Swegle, J.A.

1996-05-01

285

Performance Characteristics of Tandem-Structure Fans for Redundant Cooling of Electronic Equipment  

NASA Astrophysics Data System (ADS)

We have measured the fan performance characteristics and sound pressure level of tandem fans suitable for redundant cooling systems of electronic equipment. Maximum static pressure of tandem fans without flow-regulate-plate is 1.5 time of single fan at no fan spacing. It increases with fan spacing and reaches 1.9 time at fan spacing of 400 mm. Maximum static pressure of tandem fans with flow-regulate-plate which is symmetrical to the axis of fans is about 1.9 to 2.0 times of single fan, and it dose not affected by fan spacing. Improvement of performance characteristics is larger with longer flow-regulate-plate that is slightly shorter than fan spacing. For example, the plate length of 75 mm is found to be almost optimum for fan spacing of 100 mm. When one of the tandem fans is stopped, performance characteristics is about 80 to 90 % of single fan, and rotational speed of stopped fan is almost proportional to the volume flow rate of operating fan. Sound pressure level of tandem fans without load at normal operating condition is reduced by nearly 8 dB at maximum by changing fan spacing from 0 mm to 300 mm.

Matsushima, Hitoshi; Fukuda, Hiroshi

286

Lorentz-Abraham-Dirac versus Landau-Lifshitz radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)  

SciTech Connect

When the parameters of electron-extreme power laser interaction enter the regime of dominated radiation reaction, the electron dynamics changes qualitatively. The adequate theoretical description of this regime becomes crucially important with the use of the radiation friction force either in the Lorentz-Abraham-Dirac form, which possesses unphysical runaway solutions, or in the Landau-Lifshitz form, which is a perturbation valid for relatively low electromagnetic wave amplitude. The goal of the present paper is to find the limits of the Landau-Lifshitz radiation force applicability in terms of the electromagnetic wave amplitude and frequency. For this, a class of the exact solutions to the nonlinear problems of charged particle motion in the time-varying electromagnetic field is used.

Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K. [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); Bulanov, Stepan S. [University of California, Berkeley, California 94720 (United States)

2011-11-15

287

Self-Induced Transparency and Electromagnetic Pulse Compression in a Plasma or an Electron Beam under Cyclotron Resonance Conditions  

SciTech Connect

Based on analogy to the well-known process of the self-induced transparency of an optical pulse propagating through a passive two-level medium we describe similar effects for a microwave pulse interacting with a cold plasma or rectilinear electron beam under cyclotron resonance condition. It is shown that with increasing amplitude and duration of an incident pulse the linear cyclotron absorption is replaced by the self-induced transparency when the pulse propagates without damping. In fact, the initial pulse decomposes to one or several solitons with amplitude and duration defined by its velocity. In a certain parameter range, the single soliton formation is accompanied by significant compression of the initial electromagnetic pulse. We suggest using the effect of self-compression for producing multigigawatt picosecond microwave pulses.

Ginzburg, N. S.; Zotova, I. V.; Sergeev, A. S. [Institute of Applied Physics, RAS, GSP-120 N. Novgorod (Russian Federation)

2010-12-30

288

Thermal effects on the propagation of large-amplitude electromagnetic waves in magnetized relativistic electron-positron plasma  

NASA Astrophysics Data System (ADS)

The propagation of circularly polarized electromagnetic waves along a constant background magnetic field in an electron-positron plasma is calculated by means of both a fluid and a kinetic theory treatment. In the fluid theory, relativistic effects are included in the particle motion, the wave field, and in the thermal motion by means of a function f, which depends only on the plasma temperature. In this work we analyze the consistency of the fluid results with those obtained from a kinetic treatment, based on the relativistic Vlasov equation. The corresponding kinetic dispersion relation is numerically studied for various temperatures, and results are compared with the fluid treatment. Analytic expressions for the Alfvén velocity are obtained for the fluid and kinetic models, and it is shown that, in the kinetic treatment, the Alfvén branch is suppressed for large temperatures.

Domínguez, Macarena; Muñoz, Víctor; Valdivia, Juan Alejandro

2012-05-01

289

Electromagnetic Radiation: On Trial  

NSDL National Science Digital Library

This activity introduces students to the properties of electromagnetic radiation in a variety of ways. For example, they put the different types of the electromagnetic radiation on trial, selecting the judge, prosecutor, defense counsel, and jury, and learning about electromagnetic energy by arguing the pros and cons of each wavelength. During this activity, students are introduced to the general properties of electromagnetic waves, learn to analyze the relation between the specific properties of waves and their position in the electromagnetic spectrum, and discuss methods used to detect and analyze different waves. Students also learn about scientists whose work contributed to our understanding of electromagnetic energy. Students are encouraged to use an electronic bulletin board to communicate with each other, posting insights, ideas, evidence and questions on electromagnetic energy.

2007-05-16

290

First Measurements of the Unique Influence of Spin on the Energy Loss of Ultrarelativistic Electrons in Strong Electromagnetic Fields  

SciTech Connect

Although some authors have claimed that the effect is not detectable, we show experimentally for the first time that as the quantum parameter {chi} grows beyond 1, an increasingly large part of the hard radiation emitted arises from the spin of the electron. Results for the energy loss of electrons in the energy range 35--243GeV incident on a W single crystal are presented. Close to the axial direction the strong electromagnetic fields induce a radiative energy loss which is significantly enhanced compared to incidence on an amorphous target. In such continuously strong fields, the radiation process is highly nonperturbative for ultrarelativistic particles and a full quantum description is needed. The remarkable effect of spin flips and the energy loss is connected to the presence of a field comparable in magnitude to the Schwinger critical field, E{sub 0}=m{sup 2}c{sup 3}/e{Dirac_h} , in the rest frame of the emitting electron.

Kirsebom, K.; Mikkelsen, U.; Uggerhoj, E.; Elsener, K.; Ballestrero, S.; Sona, P.; Vilakazi, Z. Z.

2001-07-30

291

Electromagnetic analysis by finite elements of electron guns for traveling wave tubes  

Microsoft Academic Search

Electron guns are used as electron beam source in a wide variety of devices including traveling wave tubes (TWT), klystrons and particle accelerators. Usage of more complex geometries and insertion of control grid allow the designer to obtain a better performance but it requires specialized 3D numerical simulators to carry out the design process. In this paper we present the

S. Coco; S. Corsaro; R. Dionisio; A. Laudani; R. Martorana; G. Pollicino

2004-01-01

292

Hybrid two-dimensional Monte-Carlo electron transport in self-consistent electromagnetic fields  

SciTech Connect

The physics and numerics of the hybrid electron transport code ANTHEM are described. The need for the hybrid modeling of laser generated electron transport is outlined, and a general overview of the hybrid implementation in ANTHEM is provided. ANTHEM treats the background ions and electrons in a laser target as coupled fluid components moving relative to a fixed Eulerian mesh. The laser converts cold electrons to an additional hot electron component which evolves on the mesh as either a third coupled fluid or as a set of Monte Carlo PIC particles. The fluids and particles move in two-dimensions through electric and magnetic fields calculated via the Implicit Moment method. The hot electrons are coupled to the background thermal electrons by Coulomb drag, and both the hot and cold electrons undergo Rutherford scattering against the ion background. Subtleties of the implicit E- and B-field solutions, the coupled hydrodynamics, and large time step Monte Carlo particle scattering are discussed. Sample applications are presented.

Mason, R.J.; Cranfill, C.W.

1985-01-01

293

Electronic control and method for increasing efficiency of heating and cooling systems  

SciTech Connect

A method is described of increasing efficiency of a cooling system having a compressor, cooling coils, an inlet where air enters the cooling system, an outlet whereby air exists the cooling system, a fan which circulates air through the cooling system and a control for turning the compressor and the fan on and off, comprising: positioning a first temperature sensing means in the outlet; measuring the time the compressor is on during normal operation of the cooling system in cooling a room from a first temperature to a second temperature; when cooling is again required, cycling the compressor on for a fractional period of the time the compressor is on during normal operation and off for a sufficient time for the head pressure of the compressor to equalize and continuing to operate the fan while the compressor is on and while the compressor is off until the room reaches a desired temperature; turning the fan off whenever the outlet reaches a third temperature before the room reaches the desired temperature, and continuing the cycling until the room reaches the desired temperature.

Rogers, C.F. III

1987-07-28

294

A conduction-cooled, 680-mm-long warm bore, 3-T Nb3Sn solenoid for a Cerenkov free electron laser  

Microsoft Academic Search

A compact, cryocooler cooled Nb3Sn superconducting magnet system for a Cerenkov free electron laser has been designed, fabricated and tested. The magnet is positioned directly behind the electron gun of the laser system. The solenoidal field compresses and guides a tube-shaped 100 A, 500 kV electron beam. A two-stage GM cryocooler, equipped with a first generation ErNi5 regenerator, cools the

W. A. J. Wessel; A. den Ouden; H. J. G. Krooshoop; H. H. J. ten Kate; T. Wieland; P. J. M. van der Slot

1999-01-01

295

On the use of a small-scale two-phase thermosiphon to cool high-power electronics  

Microsoft Academic Search

An experimental and analytical investigation of the steady-state thermal-hydraulic operating characteristics of a small-scale two-phase thermosiphon cooling actual power electronics are presented. Boiling heat transfer coefficients and circulation mass velocities were measured while varying heat load and pressure. Both a plain and augmented riser structure, utilizing micro-fins and reentrant cavities, were simultaneously tested. The boiling heat transfer coefficients increased with

D. S. Schrage

1990-01-01

296

Electronics and Electrical Engineering Laboratory, Electromagnetic Technology Division: Programs, Activities, and Accomplishments.  

National Technical Information Service (NTIS)

Contents: Welcome; Quantum Standards; Quantum Voltage; Johnson Noise Thermometry; Single Electronics for Standards and Metrology; Physics of Quantum Hall Resistance Standards; Quantum Information; Quantum Computing; Quantum Communication; Quantum Measurem...

2003-01-01

297

Coupling of transient ultra wide band electro-magnetic fields to complex electronic systems  

Microsoft Academic Search

In this paper the coupling of transient ultra wide band field pulses to complex electronic systems is determined. Different test setups of microcontroller circuits were used to investigate the coupling effects and to describe the injected interference parameters.

M. Camp; H. Garbe; F. Sabath

2005-01-01

298

Spectroscopy and dynamics of jet-cooled hydrazines and ammonia. II. Electron-impact dissociative ionization  

SciTech Connect

Dissociative-ionization cross sections, fragment appearance potentials, and fragment kinetic energies were measured for electron-impact excitation of jet-cooled NH[sub 3], hydrazine (N[sub 2]H[sub 4]), and monomethyl hydrazine (MMH) over an energy range of 10--270 eV. A data base of 35 parent and fragment ions is reported. All measurements were made in a crossed electron--molecular beam apparatus using pulsed extraction and time-of-flight mass detection to ensure field-free excitation and high collection efficiency for energetic ions. Cross sections for NH[sub 3] ionization are in good agreement with previous measurements except for ions with high kinetic energy (KE). These discrepancies are attributed to instrument-dependent KE detection efficiencies in the previous results. Cross section data have not been previously reported for N[sub 2]H[sub 4] and MMH. The measured cross sections for total ionization at 70 eV are 2.35 A[sup 2] (NH[sub 3]), 3.76 A[sup 2] (N[sub 2]H[sub 4]), and 4.20 A[sup 2] (MMH). KE distributions were measured by an ion deflection method and gave results consistent with time-of-flight peak-shape analysis. Mean KE values [lt][epsilon] [ital t][gt] are reported for all fragment ions studied. For 170-eV excitation of NH[sub 3], [lt][epsilon] [ital t][gt] varied from 0.026 eV (NH[sub 2][sup +]) to 1.4 eV (H[sup +]). The kinetic energies for N[sub 2]H[sub 4] and MMH fragment ions at similar excitation energies are typically much lower than for fragment ions from NH[sub 3], conforming to statistical arguments based on density of internal states. High resolution mass spectra were recorded for MMH in order to distinguish different fragment ions of the same unit mass.

Syage, J.A. (The Aerospace Corporation, P. O. Box 92957/M5-754, Los Angeles, California 90009 (United States))

1992-11-01

299

A self-tuning electromagnetic vibration absorber with adaptive shunt electronics  

NASA Astrophysics Data System (ADS)

Tuned vibration absorbers (TVAs) are effective devices for vibration control in the presence of tonal excitation, but when the properties of the host structure change or the excitation frequency varies they become detuned and their performance can degrade to an unacceptable level. It is therefore desirable that the properties of the TVA can adapt to maintain optimal tuning. In this paper an electromagnetic device with an adaptive synthetic shunt impedance which provides a controllable effective mechanical stiffness and damping is proposed. The shunt impedance, comprising resistance and capacitance, is implemented digitally and can be altered in real-time to allow the system to adapt. A model-based feedforward controller is designed and implemented to adapt both the shunt resistance and capacitance to ensure the tuned frequency of the vibration absorber tracks the excitation frequency. This ensures that the system has optimal performance throughout a large range of excitation frequencies. Simulations and experimental results show that the adaptive controller can successfully adapt the system to track a variable excitation frequency and hence demonstrates better performance than the equivalent non-adaptive undamped system, as well as an optimally tuned damped system.

McDaid, A. J.; Mace, B. R.

2013-10-01

300

HIGH-ORDER MODELING OF AN ERL FOR ELECTRON COOLING IN THE RHIC LUMINOSITY UPGRADE USING MARYLIE/IMPACT.  

SciTech Connect

Plans for the RHIC luminosity upgrade call for an electron cooling system that will place substantial demands on the energy, current, brightness, and beam quality of the electron beam. In particular, the requirements demand a new level of fidelity in beam dynamics simulations. New developments in MARYLIE/IMPACT have improved both the space charge computations for beams with large aspect ratios and the beam dynamic computations for rf cavities. We present the results of beam dynamics simulations that include the effects of space charge and nonlinearities, and aim to assess the tolerance for errors and nonlinearities on current designs for a super-conducting ERL.

RANJBAR,V.; BEN-ZVI,I.; PAUL, K.; ABELL, D.T.; TECH-X CORP.; KEWISCH, J.; RYNE, R.D.; QIANG, J.

2007-06-25

301

Energy Gain of a Free Electron in a Pulsed Electromagnetic Plane Wave with Constant External Magnetic Fields  

NASA Astrophysics Data System (ADS)

We consider free electron interactions with a pulsed plane electromagnetic (EM) wave in the presence of static homogeneous magnetic fields. The main goal of this study is to find the energy gained by the electron after the wave has passed. We use the constants of motion, expressed in terms of the EM vector potential, which can be obtained from the relativistic equation of motion for a charged particle. For a constant magnetic field along the axis of the wave an exact solution is obtained for the energy gain for arbitrarily polarized EM plane wave with a Gaussian amplitude profile. It shows that significant energy gain is possible when the rest mass cyclotron frequency is resonant with the frequency of the wave, but that it decays exponentially when we deter from this resonance. For magnetic fields transverse to the axis of the wave it is shown that the governing equations can be reduced to a two-dimensional Hamiltonian system that when time-averaged in the in the limit where the cyclotron frequency is much less than that of the wave remain in Hamiltonian form. Solutions are sought in this limit for these time-averaged equations using both a Gaussian and step function profile for the wave. For both cases it is found that the maximum energy gain is independent of the size of the transverse magnetic fields and scales with the wave amplitude squared. This work was supported the US DoE under Grant DE-FG02-04ER54739.

Angus, Justin; Krasheninnikov, Sergei

2009-11-01

302

Higher-order processes in the electromagnetic production of electron-positron pairs in relativistic heavy-ion collisions  

SciTech Connect

We study higher-order effects in the electromagnetic production of electron-positron pairs in relativistic heavy-ion collisions. Treating the field of the heavy ions as an external field and neglecting the interaction among electrons and positrons, we show that the [ital N]-pair creation amplitude is the antisymmetrized product of [ital N] one-pair creation amplitudes and the vacuum amplitude. Neglecting contributions coming from exchange terms, we show that the total probability for [ital N] pairs is approximately a Poisson distribution. We investigate further the structure of the reduced one-pair amplitude, concentrating especially on multiple-particle corrections. We calculate the first of these corrections in second-order Magnus theory based on our previous result [Phys. Rev. A 49, 1584 (1994)] in the second-order Born approximation for impact parameter [ital b] zero. Explicit calculations show that the total probability is increased up to 10% by this correction for realistic collider parameters. The calculations can also be used to confirm the use of the Poisson distribution for the total probability.

Hencken, K.; Trautmann, D. (Institut fuer Theoretische Physik der Universitaet Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland)); Baur, G. (Institut fuer Kernphysik (Theorie), Forschungszentrum Juelich, 52425 Juelich (Germany))

1995-02-01

303

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Schlueter, R.D.; Deis, G.A.

1991-03-20

304

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles. 14 figs.

Schlueter, R.D.; Deis, G.A.

1992-03-24

305

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)

1992-01-01

306

Geant4 physics processes for microdosimetry simulation: Very low energy electromagnetic models for electrons in silicon  

NASA Astrophysics Data System (ADS)

The Energy-Loss Function (ELF) of silicon is used to calculate differential and total inelastic cross-sections of incident electrons. The model is validated in the 50 eV-50 keV incident energy range by comparing the inelastic cross-sections, stopping powers, and ranges to experimental and calculated data from the literature. It is applicable down to 16.7 eV. The cross sections are then used to simulate low-energy electron tracks in silicon with Geant4, using a similar implementation as the Geant4-DNA extension; this new Geant4 extension is called MuElec. Generation of low-energy electrons is clearly seen. The obtained ranges are consistent with experimental data.

Valentin, A.; Raine, M.; Sauvestre, J.-E.; Gaillardin, M.; Paillet, P.

2012-10-01

307

Quantum Electrodynamics. III. The Electromagnetic Properties of the Electron-Radiative Corrections to Scattering  

Microsoft Academic Search

The discussion of vacuum polarization in the previous paper of this series was confined to that produced by the field of a prescribed current distribution. We now consider the induction of current in the vacuum by an electron, which is a dynamical system and an entity indistinguishable from the particles associated with vacuum fluctuations. The additional current thus attributed to

Julian Schwinger

1949-01-01

308

Advanced fillers for electronics encapsulation and electro-magnetic compatibility (EMC)  

Microsoft Academic Search

EMC self-shielding in electronics packaging has become possible with the use of specially configured Ferro-silicate powder, which is a by-product from another process. Present transfer moulded microelectronics packages dominate the packaging of the multi-billion semiconductor devices manufactured annually. These make use primarily of epoxy thermosets which are compounded with compatible inorganic particle \\

Nihal Sinnadurai

2006-01-01

309

Development of Nbn Hot Electron Bolometric Mixer for Terahertz Frequencies: the Phonon-Cooled Version  

NASA Astrophysics Data System (ADS)

NbN HEB mixers represent a promising approach for achieving receiver noise temperatures of a few times the quantum noise limit at frequencies above 1 THz. NbN HEB devices have been shown to have sufficient bandwidth for applications in astronomy, remote sensing, and plasma diagnostics in the FIR range. The NbN HEB is a phonon cooled bolometer in which the energy is transfered from the hot electrons to the substrate via inelastic collisions with phonons. The development of an NbN HEB mixer contained two steps: (1) implementing mixing in a comparatively large 'direct-coupled' prototype device which required LO power of a few milliwatts, and (2) optimization of the first step by the development of an 'antenna-coupled' (quasi-optically coupled) device with an LO power level of less than one ? W. The LO power was coupled to the antenna via an extended hemispherical lens (1.3 mm in diameter). The design, fabrication, and measurement stages were performed by a collaborative effort between a Russian team from the Department of Physics at Moscow State Pedagogical University in Moscow, the Submillimeter Technology Laboratory at UMass/Lowell and the Department of Electrical and Computer Engineering at UMass/Amherst. Mixing at 2.5 THz was demonstrated for the first time using the direct-coupled device achieving an intrinsic conversion loss of 23 dB. Sufficient level of LO power coupling at four different frequencies was demonstrated with the antenna-coupled device. The antenna/lens configuration has performed as well as expected insuring coupling to LO power of less than one ?W. A 3 dB conversion gain was demonstrated with the antenna-coupled device using a laser LO at 1.56 THz with an IF frequency of 500 KHz. A second laser was utilized as the rf source. Noise temperature for the NbN HEB mixer receiver of 5800 K has been demonstrated over the 1.25-1.75 GHz IF band. The mixer temperature was 2500 K and the total conversion loss was 27 dB. Further optimization of the receiver configuration and device fabrication as well as additional development in mixer modeling will gradually lead to lower noise temperatures.

Gerecht, Eyal

310

Electron-Driven Molecular Processes Induced in Biological Systems by Electromagnetic and Other Ionizing Sources  

NASA Astrophysics Data System (ADS)

We describe, and analyse in some detail, a selection of the most recent theoretical and computational models which attempt to explain, at the molecular level, the dynamics of metastable negative ion formation from biological molecules in the gas-phase. Such Transient Negative Ions (TNIs) are related to the nanoscopic nuclear dynamics presiding over the occurrence of irreversible damage in the biosystems through the many possible pathways leading to dissociative attachment decay of the initial TNI. We will review the theoretical approach we adopted to study electron-molecule collision as applied to systems of biological interest. The connection between the spatial symmetry of the metastable anion and its role during the dissociative electron attachment event is also discussed and analysed through several examples.

Baccarelli, I.; Gianturco, F. A.; Grandi, A.; Lucchese, R. R.; Sanna, N.

311

Electron beam excitation of left-handed surface electromagnetic waves at artificial interfaces  

SciTech Connect

In this Brief Report we present the theoretical analysis of excitation of the surface plasmon polaritons by a thin electron beam propagating in the vacuum gap separating a plasmalike medium (metal) from an artificial dielectric with negative magnetic permeability. We have obtained and discussed the dispersion relation for the vacuum-gap-localized waves for an arbitrary vacuum-gap width. We have shown that the interface-localized waves with the negative total energy flux can be excited.

Averkov, Yu. O.; Kats, A. V.; Yakovenko, V. M. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian National Academy of Sciences, 12 Acad. Proskura Str., 61085 Kharkov (Ukraine)

2009-05-15

312

Amplification of electromagnetic waves by a ring-beam distribution of moderately relativistic electrons  

Microsoft Academic Search

The possibility of a new mechanism for the excitation of unstable modes in cold background plasmas is indicated in this paper. These beam-cyclotron modes are excited by the presence of the ring-beam distribution of suprathermal electrons. The usual eigenmode excitation of a cold plasma is reviewed, and the new type of instability is examined using a single-harmonic approximation and multiharmonic

B. R. Shi; J. D. Gaffey Jr.; C. S. Wu

1986-01-01

313

Cool circuits  

Microsoft Academic Search

Our culture has trained people to think that digital is the way of the future. Computers are digital. Cell phones are digital. Cameras are digital. Everything good one day will be digital. Students do not see where analog electronics fit into their lives, nor do they see any cool applications of analog electronics. This paper discusses several demonstrations and design

Marc E. Herniter

2005-01-01

314

Electromagnetic acceleration of material from a plate hit by a pulsed electron beam  

SciTech Connect

An intense pulsed electron beam traversing a thin metal plate creates a volume of dense plasma. Current flows in this plasma as a result of the charge and magnetic field introduced by the relativistic electrons. A magnetic field may linger after the electron beam pulse because of the conductivity of the material. This field decays by both diffusing out of the conducting matter and causing it to expand. If the magnetized matter is of low density and high conductivity it may expand quickly. Scaling laws for this acceleration are sought by analyzing the idealization of a steady axisymmetric flow. This case simplifies a general formulation based on both Euler`s and Maxwell`s equations. As an example, fluid with conductivity {sigma} = 8 x 10{sup 4} Siemens/m, density {rho} = 8 x 10{sup -3} kg/m{sup 3}, and initially magnetized to B = 1 Tesla can accelerate to v = 10{sup 4} m/s within a distance comparable to L = 1 mm and a time comparable to {sigma}{mu}L{sup 2} = 100 ns, which is the magnetic diffusion time. If instead, {sigma} = 8 x 10{sup 3} Siemens/m and {rho} = 8 x 10{sup -5} kg/m{sup 3} then v = 10{sup 5} m/s with a magnetic diffusion time {sigma}{mu}L{sup 2} = 10 ns. These idealized flows have R{sub M} = {sigma}{mu}vL = 1, where R{sub M} is the magnetic Reynolds number. The target magnetizes by a thermal electric effect.

Garcia, M.

1998-04-16

315

The theory of electro-magnetic radiation of electron transiting through the resonance-tunnel structure  

SciTech Connect

The quasi-stationary electron states are studied in the three-barrier resonance-tunnel structure which is the basic element of coherent quantum cascade lasers. In the models of rectangular and delta-barrier potentials there is established theory of evolution and collapse of double resonance complexes in a symmetric resonance-tunnel structure. The induced conductivity of nano-system is calculated within the both models. It is shown that the negative induced conductivity of three-barrier resonance-tunnel structure in delta-barrier model is dozens times smaller than more realistic magnitudes obtained within the rectangular potentials model.

Tkach, M.; Seti, Ju.; Voitsekhivska, O.; Fartushynsky, R. [Fedkovych Chernivtsi National University, 2 Kotsyubinskoho Str., 58012 Chernivtsi (Ukraine)

2009-12-14

316

Slalom Channeling of Trojan Electrons in 1-Dimensional Ion Chains in Linearly Polarized Electromagnetic Field  

NASA Astrophysics Data System (ADS)

We have recently discovered that two positively charged ions placed in the linearly polarized (LP) field aligned with to the symmetry line joining the ion charges and with the frequency twice the closed motion can support stable nondispersing Trojan wavepackets moving on perfectly 8-shaped trajectories [1]. Here we show that halfs of such trajectories can be connected to spline into long range oscillatory motion in the linear chain of positively charged ions. This results in long distance slalom channeling of electron travelling in Trojan state for a distance of large multiple of the ionic lattice constant. To keep the wavepacket nondispersing the LP field polarization must be perpendicular to the electron motion and strictly adjusted to the the period when the packet is passing and avoiding the neighboring ions. The channeling event is extremely rare in the phase space and requires the precise choice of the wave packet momentum and the initial position at the beginning of the long range oscillatory motion. For the majority of wrong initial conditions the motion results in fast trajectory binding on one of the chain ions. Numerical simulations with the split operator method are also provided. [1] M. Kalinski, ``Trojan-Like Wavepackets on 8-shaped orbits in Linearly Polarized Elctromagnetic Field in Hydrogen Ion Molecule,'' FiO 2009/LS XXV Annual Meeting, San Jose, California, October 2009.

Kalinski, Matt

2011-06-01

317

Integrated three-dimensional module heat exchanger for power electronics cooling  

DOEpatents

Embodiments discussed herein are directed to a power semiconductor packaging that removes heat from a semiconductor package through one or more cooling zones that are located in a laterally oriented position with respect to the semiconductor package. Additional embodiments are directed to circuit elements that are constructed from one or more modular power semiconductor packages.

Bennion, Kevin; Lustbader, Jason

2013-09-24

318

Narrow channel heat sink for cooling of high powered electronic components  

Microsoft Academic Search

The authors show the results of narrow channel heat sinks used for cooling of high powered components. The results of the experimental simulation for various air delivery methods are reported. The results show the difference in the thermal performance of the heat sink with top clearance versus ducted systems. In addition, effects of component layout power variation and air velocity

K. Azar; R. S. McLeod; R. E. Caron

1992-01-01

319

Electromagnetic probes of molecular motors in the electron transport chains of mitochondria and chloroplasts  

NASA Astrophysics Data System (ADS)

We report on measurements of harmonics generated by whole cells, mitochondria, and chloroplasts in response to applied sinusoidal electric fields. The frequency- and amplitude-dependence of the induced harmonics exhibit features that correlate with physiological processes. Budding yeast (S. cerevisiae) cells produce numerous harmonics, the amplitudes of which depend strongly on frequency. When the second or third harmonic amplitude is plotted vs. applied frequency, we observe two peaks, around 3 kHz and 12 kHz, which are suppressed by respiratory inhibitors. We observe similar peaks when measuring the harmonic response of B. indicas, a relative of the mitochondrial ancestor. In uncoupled mitochondria, in which most of the electron transport chain is active but the ATP-synthase molecular turbine is inactive, only one (lower frequency) of the two peaks is present. Finally, we find that harmonics generated by chloroplasts depend dramatically on incident light, and vanish in the absence of light.

Miller, J. H., Jr.; Nawarathna, D.; Vajrala, V.; Gardner, J.; Widger, W. R.

2005-12-01

320

Numerical calculation of dynamical friction in electron cooling systems, including magnetic field perturbations and finite time effects  

SciTech Connect

The orders-of-magnitude higher luminosities required by future electron-ion collider concepts require a dissipative force to counteract the numerous factors acting to gradually increase the phase space volume of relativistic ion beams. High-energy electron cooling systems could provide the necessary dissipation via dynamical friction, but will have to be designed for new parameter regimes. It is expected that magnetic field errors, finite interaction time and other effects will reduce the dynamical friction and hence increase the cooling time, so improved understanding of the underlying dynamics is important. We present a generalized form of the classical field-free friction force equation, which conveniently captures some of these effects. Previous work (Bell et al 2008 J. Comput. Phys. 227 8714) shows both numerical and conceptual subtleties associated with undersampling of strong collisions, and we present a rigorous mathematical treatment of such difficulties, based on the use of a modified Pareto distribution for the electron-ion impact parameters. We also present a very efficient numerical algorithm for calculating the dynamical friction on a single ion in the field free case. For the case of arbitrary magnetic field errors, we present numerical simulation results, showing agreement with our generalized friction force formula.

Sobol, A.V.; Fedotov, A.; Bruhwiler, D.L.; Bell, G.I.; Litvinenko, V.

2010-09-24

321

Nonlinear quantum theory of stimulated Cherenkov radiation of transverse electromagnetic waves from a low-density relativistic electron beam in a dielectric medium  

SciTech Connect

A nonlinear quantum theory of stimulated Cherenkov radiation of transverse electromagnetic waves from a low-density relativistic electron beam in an isotropic dielectric medium is presented. A quantum model based on the Klein-Gordon equation is used. The growth rates of beam instabilities caused by the effect of stimulated Cherenkov radiation have been determined in the linear approximation. Mechanisms of the nonlinear saturation of relativistic quantum Cherenkov beam instabilities have been analyzed and the corresponding analytical solutions have been obtained.

Bobylev, Yu. B.; Kuzelev, M. V. [Moscow State University, Faculty of Physics (Russian Federation)

2012-06-15

322

Comment on ''Electron acceleration by a short laser beam in the presence of a long-wavelength electromagnetic wave'' [J. Appl. Phys. 102, 056106 (2007)  

SciTech Connect

Gupta et al.[J. Appl. Phys. 102, 056106 (2007)] investigated vacuum electron acceleration by a short laser beam in the presence of a long-wavelength electromagnetic wave. However, we consider that their simulation results to be questionable. We have investigated their simulation in detail and present our own simulation results, which do not match the good acceleration as theirs given in the original paper.

Yuan, C. J.; Wang, P. X. [Applied Ion Beam Physics Laboratory, Key Laboratory of the Ministry of Education, China and Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Huang, S. J. [Department of Physics, Zhanjiang Normal University, Zhanjiang, Guangdong Province 524048 (China); Wang, J. X. [State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062 (China)

2012-05-15

323

High frequency electromagnetic modes in a weakly magnetized relativistic electron plasma  

SciTech Connect

Using the linearized Vlasov-Maxwell model, the polarization tensor for a weakly magnetized electron plasma is derived. For isotropic relativistic Maxwellian velocity distribution function, dispersion relations are obtained for both parallel and perpendicular propagations. The integrals (called Meijer G functions) that arise due to relativistic effects are examined in various limits and dispersion relations are derived for the nonrelativistic, weakly, strongly, and ultrarelativistic Maxwellian velocity distributions. It is generally observed that the propagation domains of the modes are enlarged as one proceeds from the nonrelativistic to the highly relativistic regime. Resultantly, due to the relativistic effects, the Whistler mode is suppressed in the R-wave, the nonpropagation band of X-mode is reduced, and the X-mode itself approaches the O-mode. Further, the results derived in the ultra- and nonrelativistic limits found to be in agreement with the earlier calculations [G. Abbas et al. Phys. Scr. 76, 649 (2007); F. F. Chen, Introduction to Plasma Physics and Controlled Fusion (Plenum, New York, 1984), Vol. 1].

Abbas, Gohar; Murtaza, G. [Department of Physics, G. C. University, Lahore 54000 (Pakistan); Kingham, R. J. [Plasma Physics Group, Imperial College, Blackett Laboratory, London SW7 2AZ (United Kingdom)

2010-07-15

324

NbN phonon-cooled hot-electron bolometer mixer for terahertz heterodyne receivers  

Microsoft Academic Search

We present the results of our studies of NbN phonon-cooled HEB mixers at terahertz frequencies. The mixers were fabricated from NbN film deposited on a high-resistivity Si substrate with an MgO buffer layer. The mixer element was integrated with a log-periodic spiral antenna. The noise temperature measurements were performed at 2.5 THz and at 3.8 THz local oscillator frequencies for

Gregory N. Gol'tsman; Yuriy B. Vachtomin; Sergey V. Antipov; Matvey I. Finkel; Sergey N. Maslennikov; Konstantin V. Smirnov; Stanislav L. Polyakov; Sergey I. Svechnikov; Natalia S. Kaurova; Elisaveta V. Grishina; Boris M. Voronov

2005-01-01

325

Nonstationary nonlinear processes during the interaction between an electron beam and an electromagnetic field at the passband boundary of an electrodynamic system. I - The high-frequency boundary  

NASA Astrophysics Data System (ADS)

Computer-simulation results are presented on transient processes arising during the interaction between an electron beam and fields of an electrodynamic system at the high-frequency passband boundary. Depending on the parameters, the system can have the properties of a BWT, a TWT, or a resonance oscillator. Regions of the parameter space are specified in which regimes of stationary oscillation, self-modulation, hard excitation, and hysteresis are achieved. A qualitative explanation of the observed phenomena is given consisting in a mean velocity decrease of the electron beam connected with the transfer of its kinetic energy to the electromagnetic field.

Bulgakova, L. V.; Kuznetsov, S. P.

326

Frequency bandwidth and conversion loss of a semiconductor heterodyne receiver with phonon cooling of two-dimensional electrons  

SciTech Connect

The temperature and concentration dependences of the frequency bandwidth of terahertz heterodyne AlGaAs/GaAs detectors based on hot electron phenomena with phonon cooling of two-dimensional electrons have been measured by submillimeter spectroscopy with a high time resolution. At a temperature of 4.2 K, the frequency bandwidth at a level of 3 dB (f{sub 3dB}) is varied from 150 to 250 MHz with a change in the concentration n{sub s} according to the power law f{sub 3dB} {proportional_to} n{sub s}{sup -0.5} due to the dominant contribution of piezoelectric phonon scattering. The minimum conversion loss of the semiconductor heterodyne detector is obtained in structures with a high carrier mobility ({mu} > 3 x 10{sup 5} cm{sup 2} V{sup -1} s{sup -1} at 4.2 K).

Shangina, E. L., E-mail: shangina@rplab.ru; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol'tsman, G. N.; Verevkin, A. A. [Moscow State Pedagogical University (Russian Federation); Toropov, A. I. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2010-11-15

327

An Electromagnetic Spectrum for Millennial Students: Teaching Light, Color, Energy, and Frequency Using the Electronic Devices of Our Time  

NSDL National Science Digital Library

In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum usin

Murphy, Maureen K.

2010-07-01

328

Effects of high-energy particle showers on the embedded front-end electronics of an electromagnetic calorimeter for a future lepton collider  

NASA Astrophysics Data System (ADS)

Application Specific Integrated Circuits, ASICs, similar to those envisaged for the readout electronics of the central calorimeters of detectors for a future lepton collider have been exposed to high-energy electromagnetic showers. A salient feature of these calorimeters is that the readout electronics will be embedded into the calorimeter layers. In this article it is shown that interactions of shower particles in the volume of the readout electronics do not alter the noise pattern of the ASICs. No signal at or above the MIP level has been observed during the exposure. The upper limit at the 95% confidence level on the frequency of fake signals is smaller than 1×10-5 for a noise threshold of about 60% of a MIP. For ASICs with similar design to those which were tested, it can thus be largely excluded that the embedding of the electronics into the calorimeter layers compromises the performance of the calorimeters.

Calice Collaboration; Adloff, C.; Francis, K.; Repond, J.; Smith, J.; Trojand, D.; Xia, L.; Baldolemar, E.; Li, J.; Park, S. T.; Sosebee, M.; White, A. P.; Yu, J.; Mikami, Y.; Watson, N. K.; Mavromanolakis, G.; Thomson, M. A.; Ward, D. R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Benyamna, M.; Cârloganu, C.; Fehr, F.; Gay, P.; Manen, S.; Royer, L.; Blazey, G. C.; Dyshkant, A.; Zutshi, V.; Hostachy, J.-Y.; Morin, L.; Cornett, U.; David, D.; Fabbri, R.; Falley, G.; Gadow, K.; Garutti, E.; Göttlicher, P.; Günter, C.; Karstensen, S.; Krivan, F.; Lucaci-Timoce, A.-I.; Lu, S.; Lutz, B.; Marchesini, I.; Meyer, N.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Vargas-Trevino, A.; Wattimena, N.; Wendt, O.; Feege, N.; Haller, J.; Richter, S.; Samson, J.; Eckert, P.; Kaplan, A.; Schultz-Coulon, H.-Ch.; Shen, W.; Stamen, R.; Tadday, A.; Bilki, B.; Norbeck, E.; Onel, Y.; Kawagoe, K.; Uozumi, S.; Dauncey, P. D.; Magnan, A.-M.; Bartsch, V.; Salvatore, F.; Laktineh, I.; Calvo Alamillo, E.; Fouz, M.-C.; Puerta-Pelayo, J.; Frey, A.; Kiesling, C.; Simon, F.; Bonis, J.; Bouquet, B.; Callier, S.; Cornebise, P.; Doublet, Ph.; Dulucq, F.; Faucci Giannelli, M.; Fleury, J.; Li, H.; Martin-Chassard, G.; Richard, F.; de La Taille, Ch.; Pöschl, R.; Raux, L.; Seguin-Moreau, N.; Wicek, F.; Anduze, M.; Boudry, V.; Brient, J.-C.; Jeans, D.; Mora de Freitas, P.; Musat, G.; Reinhard, M.; Ruan, M.; Videau, H.; Marcisovsky, M.; Sicho, P.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.

2011-10-01

329

Electromagnetic calorimetry  

NASA Astrophysics Data System (ADS)

Electromagnetic calorimetry forms a key element of almost all current high energy particle physics detectors and has widespread application in related experimental fields such as nuclear physics and astro-particle physics. It will play a particularly important role in the latest generation of experiments at the CERN Large Hadron Collider (LHC), where it is expected that high energy electrons and photons will provide some of the clearest signatures for new discoveries. This article introduces the basic concepts underlying electromagnetic calorimetry and illustrates how these principles have been applied in recent and current detector designs, explaining the connection between technical choices and specific physics goals. Designs are described in sufficient detail to demonstrate the compromises that have to be made in achieving optimum performance within practical constraints. The main emphasis is on the LHC experiments, which provide outstanding examples of the state-of-the-art. Selected examples from other domains, such as nuclear physics and neutrino experiments are also considered and particular attention is given to calorimeter design studies for the proposed International Linear Collider (ILC) where the concept of Particle Flow Analysis is being used as a guiding influence in the overall detector optimization.

Brown, R. M.; Cockerill, D. J. A.

2012-02-01

330

Particle-in-cell, self-consistent electromagnetic wave emission simulations of solar type III radio bursts: parameter space investigation and electron beam long-term evolution  

NASA Astrophysics Data System (ADS)

A recent work by Tsiklauri, Physics of Plasmas 18, 052903 (2011), presented the first attempt to produce synthetic (simulated) dynamical spectrum of the solar type III radio bursts in the fully kinetic plasma model. The latter was based on 1.5D non-zero pitch angle (non-gyrotropic) electron beam, that is an alternative to the plasma emission classical mechanism for which two spatial dimensions are needed. High-resolution, 1.5D Particle-in-Cell, relativistic, fully electromagnetic simulations were used to model electromagnetic wave emission generation in the context of solar type III radio bursts. The model studied generation of electromagnetic waves by a super-thermal, hot beam of electrons injected into a plasma thread that contains uniform longitudinal magnetic field and a parabolic density gradient. In effect, a single magnetic line connecting Sun to earth was considered, for which several cases were studied. Tsiklauri (2011) established the following: (i) The physical system without a beam is stable and only low amplitude level electromagnetic drift waves (noise) are excited. (ii) The beam injection direction is controlled by setting either longitudinal or oblique electron initial drift speed, i.e. by setting the beam pitch angle (the angle between the beam velocity vector and the direction of background magnetic field). In the case of zero pitch angle i.e. when ?c vb \\cdot ?c E?=0, the beam excites only electrostatic, standing waves, oscillating at local plasma frequency, in the beam injection spatial location, and only low level electromagnetic drift wave noise is also generated. (iii) In the case of oblique beam pitch angles, i.e. when ?c vb \\cdot ?c E? ¬ =0, again electrostatic waves with same properties are excited. However, now the beam also generates the electromagnetic waves with the properties commensurate to type III radio bursts. The latter is evidenced by the wavelet analysis of transverse electric field component, which shows that as the beam moves to the regions of lower density and hence lower plasma frequency, frequency of the electromagnetic waves drops accordingly. (iv) When the density gradient is removed, an electron beam with an oblique pitch angle still generates the electromagnetic radiation. However, in the latter case no frequency decrease is seen. Here we extend the previous analysis of Tsiklauri (2011) by presenting a full parameter space investigation and the beam's long-term time evolution. We study how the generated radio burst emission varies as a function of beam pitch angle and its temperature (which is normally different from the background plasma temperature). We established that: (i) there is an optimal angle for which the maximal radio emission occurs and (ii) in the plausible range of beam temperatures, their variation does not produce a significant effect on the generated radio emission.

Pechhacker, R.; Tsiklauri, D.

2011-12-01

331

Rotational cooling of heteronuclear molecular ions with {sup 1}{sigma}, {sup 2}{sigma}, {sup 3}{sigma}, and {sup 2}{pi} electronic ground states  

SciTech Connect

The translational motion of molecular ions can be effectively cooled sympathetically to translational temperatures below 100 mK in ion traps through Coulomb interactions with laser-cooled atomic ions. The rovibrational degrees of freedom, however, are expected to be largely unaffected during translational cooling. We have previously proposed schemes for cooling of the internal degrees of freedom of such translationally cold but internally hot heteronuclear diatomic ions in the simplest case of {sup 1}{sigma} electronic ground-state molecules. Here we present a significant simplification of these schemes and make a generalization to the most frequently encountered electronic ground states of heteronuclear molecular ions: {sup 1}{sigma}, {sup 2}{sigma}, {sup 3}{sigma}, and {sup 2}{pi}. The schemes are relying on one or two laser-driven transitions with the possible inclusion of a tailored incoherent far-infrared radiation field.

Vogelius, I.S.; Madsen, L.B.; Drewsen, M. [Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark); Danish National Research Foundation Center for Quantum Optics and Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark)

2004-11-01

332

Cooled Transmission-Mode NEA-Photocathode with a Band-Graded Active Layer for High Brightness Electron Source  

SciTech Connect

A Free-Electron Laser (FEL) places many exacting demands on a Negative Electron Affinity (NEA) photocathode, such as the need for an ultra-fast response time, low energy spread for emitted electrons, high quantum efficiency (Q.E.) and a high average photocurrent. However, these key requirements are conflicting, and cannot be fulfilled by conventional photocathode design. For example, to achieve {approx}10 ps response time, the photocathode active layer should be thinned to {approx}100-150 nm, but this thickness is insufficient to provide near-complete absorption of light with hv{approx_equal}{epsilon}{sub g} so high Q.E. cannot be achieved. Complete optical absorption and high Q.E. can be obtained using a thin active layer at higher photon energies, but this generates photoelectrons with excess kinetic energy within the semiconductor. These photoelectrons do not thermalise in a thin active layer, so yield a broad energy distribution in the emitted electrons. Moreover, cooling of the conventional semiconductor photocathode structure is ineffective due to its fragility, so it cannot be pressed firmly to a heat sink to attain good thermal contact. Consequently, the maximum CW photocurrent is limited to a few miiliamps. The goal of our work is to develop a new design of NEA-photocathode which is optimised for FEL applications.

Jones, L. B.; Militsyn, B. L.; Smith, S. L. [STFC Daresbury Laboratory, Warrington, WA4 4AD (United Kingdom); Rozhkov, S. A. [Novosibirsk State University, Novosibirsk, 630090 (Russian Federation); Bakin, V. V.; Kosolobov, S. N.; Scheibler, H. E. [Institute of Semiconductor Physics, Novosibirsk, 630090 (Russian Federation); Terekhov, A. S. [Novosibirsk State University, Novosibirsk, 630090 (Russian Federation); Institute of Semiconductor Physics, Novosibirsk, 630090 (Russian Federation)

2009-08-04

333

Applications of the remarkable pressure effect on electron beam production by cooled LiNbO3 crystals in dilute gases  

NASA Astrophysics Data System (ADS)

In 2001 we reported on focused, electron beams accelerated away from cylindrical LiNbO3 crystals in dilute gas on cooling with the -- z base exposed. These beams consisted of clusters of electrons arising from positive ion bombardment of the crystal on cooling. Even though the energy of the clusters of electrons in the beam changes with time and crystal temperature, it is nearly constant over periods of a few minutes. Remarkably, the maximum electron energy is strongly pressure dependent (more than a factor of two.) Here we show how this allows production of maximum energy bremsstrahlung^1; how the pressure effect influences electron beam energy in transport through thin tubes and how it effects electron beam intensity and focusing. 1. J. D. Brownridge and S. M. Shafroth, Appl. Phys. Letts. 85, 1298 (2004) and http://www.binghamton.edu/physics/brownridge.html

Shafroth, Stephen; Brownridge, James

2005-03-01

334

Contributions to the second workshop on medium energy electron cooling - MEEC96  

SciTech Connect

MEEC96 was a workshop devoted primarily to discussion within four working groups, not a mini-conference of prepared reports. Therefore, although there are contributions bearing the name of a single author, much of what was learned came in extemporaneous discussion of the issues posed to the participants. The original plan to produce formal proceedings has been dropped because of the limited number of participants willing to write up their own contributions and because of the difficulty of converting free-wheeling discussion to the written word. The premsise for the 1996 gathering was to set a critique of Fermilab`s R&D effort at cooling a ring of 8 GeV {bar p}`s. Separate abstracts have been submitted to the energy database for contributions to this workshop.

MacLachlan, J. [ed.

1997-09-01

335

On the use of a small-scale two-phase thermosiphon to cool high-power electronics  

NASA Astrophysics Data System (ADS)

An experimental and analytical investigation of the steady-state thermal-hydraulic operating characteristics of a small-scale two-phase thermosiphon cooling actual power electronics are presented. Boiling heat transfer coefficients and circulation mass velocities were measured while varying heat load and pressure. Both a plain and augmented riser structure, utilizing micro-fins and reentrant cavities, were simultaneously tested. The boiling heat transfer coefficients increased with both increasing heat load and pressure. The mass velocity increased with increasing pressure while both increasing and then decreasing with increasing heat load. The reentrant cavity enhancement factor, a ratio of the augmented-to-plain riser nucleate boiling heat transfer coefficients, ranged from 1 to 1.4. High-speed photography revealed bubbly, slug, churn, wispy-annular and annular flow patterns. The experimental mass velocity and heat transfer coefficient data were compared to an analytical model with average absolute deviations of 16.3 and 26.3 percent, respectively.

Schrage, D. S.

1990-01-01

336

The cooling of particle beams  

SciTech Connect

A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling with beam coupling. Laser Cooling has provided beams of the lowest temperatures, namely 1 mK, but only for ions and only for the longitudinal temperature. Recent theoretical work has suggested how laser cooling, with the coupling of beam motion, can be used to reduce the ion beam temperature in all three directions. The majority of this paper is devoted to describing laser cooling and laser cooling with beam coupling.

Sessler, A.M.

1994-10-01

337

Effects of nonlocal plasmons in gapped graphene micro-ribbon array and two-dimensional electron gas on near-field electromagnetic response in the deep subwavelength regime.  

PubMed

A self-consistent theory involving Maxwell's equations and a density-matrix linear-response theory is solved for an electromagnetically coupled doped graphene micro-ribbon array (GMRA) and a quantum well (QW) electron gas sitting at an interface between a half-space of air and another half-space of a doped semiconductor substrate, which supports a surface-plasmon mode in our system. The coupling between a spatially modulated total electromagnetic (EM) field and the electron dynamics in a Dirac-cone of a graphene ribbon, as well as the coupling of the far-field specular and near-field higher-order diffraction modes, are included in the derived electron optical-response function. Full analytical expressions are obtained with nonlocality for the optical-response functions of a two-dimensional electron gas and a graphene layer with an induced bandgap, and are employed in our numerical calculations beyond the long-wavelength limit (Drude model). Both the near-field transmissivity and reflectivity spectra, as well as their dependence on different configurations of our system and on the array period, ribbon width, graphene chemical potential of QW electron gas and bandgap in graphene, are studied. Moreover, the transmitted E-field intensity distribution is calculated to demonstrate its connection to the mixing of specular and diffraction modes of the total EM field. An externally tunable EM coupling among the surface, conventional electron-gas and massless graphene intraband plasmon excitations is discovered and explained. Furthermore, a comparison is made between the dependence of the graphene-plasmon energy on the ribbon's width and chemical potential in this paper and the recent experimental observation given by [Nat. Nanotechnol.6, 630-634 (2011)] for a GMRA in the terahertz-frequency range. PMID:23385917

Huang, Danhong; Gumbs, Godfrey; Roslyak, Oleksiy

2013-02-01

338

Quantum theory of stimulated Cherenkov emission and stimulated compton scattering of electromagnetic waves by a low-density relativistic electron beam  

SciTech Connect

A quantum theory of instabilities of a relativistic electron beam due to the stimulated Cherenkov effect in a dielectric and the stimulated Compton effect in vacuum is presented. The instability growth rates are found in a linear approximation and are shown to go over to the familiar growth rates in the classical approximation. A nonlinear theory of instabilities in the quantum case is developed. Analytic solutions are obtained that describe the nonlinear saturation of the amplitudes of the electromagnetic waves emitted by the beam.

Kuzelev, M. V. [Moscow State University (Russian Federation)

2010-07-15

339

Electromagnetic radiation from positive-energy bound electrons in the Coulomb field of a nucleus at rest in a strong uniform magnetic field  

SciTech Connect

A classical analysis is presented of the electromagnetic radiation emitted by positive-energy electrons performing bound motion in the Coulomb field of a nucleus at rest in a strong uniform magnetic field. Bounded trajectories exist and span a wide range of velocity directions near the nucleus (compared to free trajectories with similar energies) when the electron Larmor radius is smaller than the distance at which the electron-nucleus Coulomb interaction energy is equal to the mechanical energy of an electron. The required conditions occur in magnetic white dwarf photospheres and have been achieved in experiments on production of antihydrogen. Under these conditions, the radiant power per unit volume emitted by positive-energy bound electrons is much higher than the analogous characteristic of bremsstrahlung (in particular, in thermal equilibrium) at frequencies that are below the electron cyclotron frequency but higher than the inverse transit time through the interaction region in a close collision in the absence of a magnetic field. The quantum energy discreteness of positive-energy bound states restricts the radiation from an ensemble of bound electrons (e.g., in thermal equilibrium) to nonoverlapping spectral lines, while continuum radiative transfer is dominated by linearly polarized bremsstrahlung.

Arsenyev, S. A.; Koryagin, S. A., E-mail: koryagin@appl.sci-nnov.ru [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)

2012-06-15

340

Electron beam-physical vapor deposition - thermal barrier coatings on laser drilled surfaces for transpiration cooling  

Microsoft Academic Search

In this paper the deposition behavior of zirconia on laser drilled surfaces is reported. The samples were prepared with laser drilled holes (diameter 200 ?m) with tilting angles of 0°, 15°, 30°, 45° and 56°. As substrate material, VPS-MCrAlY-coated nickel-based superalloy was used. The zirconia thermal barrier coatings were deposited by the electron beam-physical vapor deposition (EB-PVD) technique. The extent

E. Lugscheider; K. Bobzin; A. Etzkorn; A. Horn; R. Weichenhain; E. W. Kreutz; R. Poprawe

2000-01-01

341

Assessment of Thermal Control Technologies for Cooling Electric Vehicle Power Electronics  

Microsoft Academic Search

The U.S. Department of Energy (DOE) FreedomCAR Program's technical targets for the electric traction system (power electronics and electric machines) of advanced vehicles require significant reductions in volume, weight, and cost while also meeting performance and 15 year life requirements (1). The performance of the semiconductor switches and diodes, the ripple-current capability of the capacitors, and the life of the

Thomas Abraham; Kevin Bennion; Desikan Bharathan; Sreekant Narumanchi; Michael O'Keefe

342

Do Type III-associated Escaping Electron Beams Cool The Corona?  

NASA Astrophysics Data System (ADS)

A recent study of decimetric Type III radio burst emission from data from the Nancay Radio Heliograph (NRH) will be presented. It examined sizes, locations, and fluxes of close to 10'000 decimetric Type III bursts. The flux study suggests that electron beams related to Type III emission could be responsible for carrying energy away from the corona in a proportion similar to that of EUV nanoflare heating. This tentative conclusion was reached from comparing Type III dN/dS distributions to the dN/dS of EUV/SXR nano-/micro-flares. The biggest uncertainty is the radiative efficiency, i.e. the ratio of radiated energy in decimetric Type III bursts and the energy of the electrons in the beams associated with them. We will constrain this value through other, new observations: we have already computed the amount of Type III radiated energy from NRH observations, and we will now compare them with the amount of energy in the corresponding beam electron detected in-situ by the Wind spacecraft. Given our sample of close to 10'000 decimetric Type IIIs, we expect a decent amount of in-situ beam energy estimates from magnetically connected events. Moreover, we will compare with X-ray-derived energies from corresponding RHESSI (micro)flares, when such an association exists.

Saint-Hilaire, Pascal; Wang, L.; Christe, S. D.; Vilmer, N.; Kerdraon, A.; Lin, R. P.

2012-05-01

343

Electromagnetically induced transparency with two dimensional electron spins 1 This paper is dedicated to Marlan O. Scully on his 60th birthday: Marlan has been a constant source of inspiration in my scientific career. 1  

Microsoft Academic Search

The electronic spin degrees of freedom in semiconductors have coherence times that are several orders of magnitude longer than other relevant timescales. We show that application of a pair of laser fields, whose frequencies differ by the Zeeman splitting, gives rise to electromagnetically induced transparency in an optically dense two-dimensional electron gas under high magnetic fields. Even though reduction in

2000-01-01

344

NbN phonon-cooled hot-electron bolometer mixer for terahertz heterodyne receivers  

NASA Astrophysics Data System (ADS)

We present the results of our studies of NbN phonon-cooled HEB mixers at terahertz frequencies. The mixers were fabricated from NbN film deposited on a high-resistivity Si substrate with an MgO buffer layer. The mixer element was integrated with a log-periodic spiral antenna. The noise temperature measurements were performed at 2.5 THz and at 3.8 THz local oscillator frequencies for the 3 x 0.2 ?m2 active area devices. The best uncorrected receiver noise temperatures found for these frequencies are 1300 K and 3100 K, respectively. A water vapour discharge laser was used as the LO source. The largest gain bandwidth of 5.2 GHz was achieved for a mixer based on 2 nm thick NbN film deposited on MgO layer over Si substrate. The gain bandwidth of the mixer based on 3.5 nm NbN film deposited on Si with MgO is 4.2 GHz and the noise bandwidth for the same device amounts to 5 GHz. We also present the results of our research into decrease of the direct detection contribution to the measured Y-factor and a possible error of noise temperature calculation. The use of a square nickel cell mesh as an IR-filter enabled us to avoid the effect of direct detection and measure apparent value of the noise temperature which was 16% less than that obtained using conventional black polyethylene IR-filter.

Gol'tsman, Gregory N.; Vachtomin, Yuriy B.; Antipov, Sergey V.; Finkel, Matvey I.; Maslennikov, Sergey N.; Smirnov, Konstantin V.; Polyakov, Stanislav L.; Svechnikov, Sergey I.; Kaurova, Natalia S.; Grishina, Elisaveta V.; Voronov, Boris M.

2005-03-01

345

Neutrino Signal of Electron-Capture Supernovae from Core Collapse to Cooling  

SciTech Connect

An 8.8M{sub {center_dot}}electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time ({approx}9 s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities ({approx}200 ms), luminosity equipartition among all species becomes almost perfect and the spectra of {nu}{sub e} and {nu}{sub {mu},{tau}}very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations.

Huedepohl, L.; Mueller, B.; Janka, H.-T.; Marek, A. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, D-85748 Garching (Germany); Raffelt, G. G. [Max-Planck-Institut fuer Physik, Werner-Heisenberg-Institut, Foehringer Ring 6, D-80802 Muenchen (Germany)

2010-06-25

346

Electromagnetic direct implicit PIC simulation  

SciTech Connect

Interesting modelling of intense electron flow has been done with implicit particle-in-cell simulation codes. In this report, the direct implicit PIC simulation approach is applied to simulations that include full electromagnetic fields. The resulting algorithm offers advantages relative to moment implicit electromagnetic algorithms and may help in our quest for robust and simpler implicit codes.

Langdon, A.B.

1983-03-29

347

Trapping of high-energy electrons into regime of surfatron acceleration by electromagnetic waves in space plasma  

SciTech Connect

The phenomenon of trapping of weakly relativistic charged particles (with kinetic energies on the order of mc{sup 2}) into a regime of surfatron acceleration by an electromagnetic wave that propagates in plasma across a weak external magnetic field has been studied using nonlinear numerical calculations based on a solution of the relativistic equations of motion. Analysis showed that, for the wave amplitude above a certain threshold value and the initial wave phase outside the interval favorable for the surfing regime, the trajectory of a charged particle initially corresponds to its cyclotron rotation in the external magnetic field. For the initial particle energies studied, the period of this rotation is relatively short. After a certain number (from several dozen to several thousand and above) of periods of rotation, the wave phase takes a value that is favorable for trapping of the charged particle on its trajectory by the electromagnetic wave, provided the Cherenkov resonance conditions are satisfied. As a result, the wave traps the charged particle and imparts it an ultrarelativistic acceleration. In momentum space, the region of trapping into the regime of surfing on an electromagnetic wave turns out to be rather large.

Erokhin, A. N.; Erokhin, N. S.; Milant'ev, V. P. [Peoples' Friendship University of Russia (Russian Federation)

2012-05-15

348

ELECTROMAGNETIC PUMP  

DOEpatents

This patent reiates to electromagnetic pumps for electricity-conducting fluids and, in particular, describes several modifications for a linear conduction type electromagnetic interaction pump. The invention resides in passing the return conductor for the current traversing the fiuid in the duct back through the gap in the iron circuit of the pump. Both the maximum allowable pressure and the efficiency of a linear conduction electromagnetic pump are increased by incorporation of the present invention.

Pulley, O.O.

1954-08-17

349

Cooling Rates in Splat Cooling.  

National Technical Information Service (NTIS)

Calculations and experimental observations made on cooling rates during splat quenching are presented. Three possible types of cooling behavior are discussed: ideal cooling, intermediate cooling, and Newtonian cooling. The effects of splatting-process var...

R. C. Ruhl

1966-01-01

350

Information Security due to Electromagnetic Environments  

NASA Astrophysics Data System (ADS)

Generally, active electronic devices emit slightly unintentional electromagnetic noise. From long ago, electromagnetic emission levels have been regulated from the aspect of electromagnetic compatibility (EMC). Also, it has been known the electromagnetic emissions have been generated from the ON/OFF of signals in the device. Recently, it becomes a topic of conversation on the information security that the ON/OFF on a desired signal in the device can be reproduced or guessed by receiving the electromagnetic emission. For an example, a display image on a personal computer (PC) can be reconstructed by receiving and analyzing the electromagnetic emission. In sum, this fact makes known information leakage due to electromagnetic emission. “TEMPEST" that has been known as a code name originated in the U. S. Department of Defense is to prevent the information leakage caused by electromagnetic emissions. This paper reports the brief summary of the information security due to electromagnetic emissions from information technology equipments.

Sekiguchi, Hidenori; Seto, Shinji

351

Electromagnetic Compatibility in Aerospace Vehicles.  

National Technical Information Service (NTIS)

Electromagnetic compatibility in aerospace vehicles which requires careful consideration because of the generally high packing density of electronic equipment aboard aircraft or spacecraft, the complex cable hardness and the required reliability margins. ...

O. B. M. Pietersen

1983-01-01

352

Materials for electromagnetic interference shielding  

Microsoft Academic Search

Materials for the electromagnetic interference (EMI) shielding of electronics and radiation sources are reviewed, with emphasis\\u000a on composite materials and resilient EMI gasket materials, which shield mainly by reflection of the radiation at a high frequency.

D. D. L. Chung

2000-01-01

353

Experimental investigation of dissociation pathways of cooled HeH{sup +} following valence electron excitation at 32 nm by intense free-electron-laser radiation  

SciTech Connect

The dissociation pathways of HeH{sup +} have been investigated below the first ionization continuum by photoabsorption at 32 nm, using fragment momentum imaging in a crossed-beams experiment at the free-electron laser in Hamburg (FLASH). Investigations were done both for ions with several vibrational levels excited in the ion source and for ions vibrationally cooled in an electrostatic ion trap prior to the irradiation. The product channels He{sup +}(1s)+H(nl) and He(1snl)+H{sup +} were separated and the He(1snl)+H{sup +} channel was particularly studied by coincidence detection of the He and H{sup +} fragments on two separate fragment detectors. At 32 nm excitation, the branching ratio between the product channels was found to be {sigma}{sub He}{sup +}{sub +H}/{sigma}{sub He+H}{sup +}=0.96{+-}0.11 for vibrationally hot and 1.70{+-}0.48 for vibrationally cold ions. The spectra of kinetic energy releases for both channels revealed that photodissociation at 32 nm leads to high Rydberg states (n > or approx. 3-4) of the emerging atomic fragments irrespective of the initial vibrational excitation of HeH{sup +}. The fragment angular distributions showed that dissociation into the He+H{sup +} channel mostly ({approx}70%) proceeds through {sup 1{Pi}} states, while for the He{sup +}+H channel {sup 1{Sigma}} and {sup 1{Pi}} states are of about equal importance.

Pedersen, H. B.; Lammich, L. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Domesle, C.; Jordon-Thaden, B.; Ullrich, J.; Wolf, A. [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Heber, O. [Department of Particle Physics, Weizmann Institute of Science, 76100 Rehovot (Israel); Treusch, R.; Guerassimova, N. [Hamburger Synchrotronstrahlungslabor at Deutsches Elektronen-Synchrotron, D-22607 Hamburg (Germany)

2010-08-15

354

Electromagnetic fasteners  

SciTech Connect

An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

Crane, Randolph W. (Idaho Falls, ID); Marts, Donna J. (Idaho Falls, ID)

1994-01-01

355

Response to ''Comment on 'Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding''' [Phys. Plasmas 17, 093103 (2010)  

SciTech Connect

Nasr and Hasanbeigi in their comment [Phys. Plasmas 17, 093103 (2010)] have claimed that, in our recent paper [Phys. Plasmas 17, 093103 (2010)], incorrect initial conditions have been used based on dispersion relation (or normalized electromagnetic wave frequency {omega}{sub w}) and mean axial velocity {beta}{sub b}. We use a self-consistent method to calculate more accurate values of {omega}{sub w} and {beta}{sub b} and show that all results presented in our recent paper are correct.

Esmaeilzadeh, Mahdi; Taghavi, Amin [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of)

2011-05-15

356

On extreme field limits in high power laser matter interactions: radiation dominant regimes in high intensity electromagnetic wave interaction with electrons  

NASA Astrophysics Data System (ADS)

We discuss the key important regimes of electromagnetic field interaction with charged particles. Main attention is paid to the nonlinear Thomson/Compton scattering regime with the radiation friction and quantum electrodynamics effects taken into account. This process opens a channel of high efficiency electromagnetic energy conversion into hard electromagnetic radiation in the form of ultra short high power gamma ray flashes.

Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K.; Nakamura, Tatsufumi; Bulanov, Stepan S.; Zhidkov, Alexei G.; Kato, Yoshiaki; Korn, Georg

2013-05-01

357

An Efficient Algorithm for Shielding Electromagnetic Topological Diagram  

Microsoft Academic Search

An electromagnetic topology method used to analyze interactions between electronic systems and electromagnetic environment is presented. Combining electromagnetic topology model with the graph theory, an efficient algorithm is obtained. The algorithm can find out all the paths which have a lower shielding coefficient than the given threshold K in the shielding electromagnetic topological diagram.

Yongfeng Wang; Chengda Yu; Chaowei Zhang

2010-01-01

358

Molecular electronics: Cool computing  

NASA Astrophysics Data System (ADS)

Proposals for carrying out computing at the molecular level generally involve current-carrying circuitry, as in conventional computers. A possible alternative, using an electrostatically operating 'cellular automata', reduces, among other things, the problem of excess heat production.

Hush, Noel

2003-03-01

359

Molecular electronics: Cool computing  

Microsoft Academic Search

Proposals for carrying out computing at the molecular level generally involve current-carrying circuitry, as in conventional computers. A possible alternative, using an electrostatically operating 'cellular automata', reduces, among other things, the problem of excess heat production.

Noel Hush

2003-01-01

360

Electromagnetic Scattering.  

National Technical Information Service (NTIS)

This report summarizes research results produced by the investigator under support of the Air Force grant. The work has been mainly concerned with the scattering of electromagnetic waves by bounded bodies of small electrical dimensions, but with some cons...

T. B. A. Senior

1983-01-01

361

Electromagnetic Fields  

MedlinePLUS

... off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need to do more research on this before they can say for sure. NIH: National Institute of Environmental Health Sciences

362

Refrigerant directly cooled capacitors  

DOEpatents

The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

Hsu, John S. (Oak Ridge, TN); Seiber, Larry E. (Oak Ridge, TN); Marlino, Laura D. (Oak Ridge, TN); Ayers, Curtis W. (Kingston, TN)

2007-09-11

363

Stochastic cooling  

SciTech Connect

Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron.

Bisognano, J.; Leemann, C.

1982-03-01

364

Emergent electromagnetism in solids  

NASA Astrophysics Data System (ADS)

The electromagnetic field (EMF) is the most fundamental field in condensed-matter physics. Interaction between electrons, electron-ion interaction and ion-ion interaction are all of electromagnetic origin, while the other three fundamental forces, i.e. the gravitational force and weak and strong interactions, are irrelevant in the energy/length scales of condensed-matter physics. Also the physical properties of condensed matter, such as transport, optical, magnetic and dielectric properties, are almost described as their electromagnetic responses. In addition to this EMF, it often happens that the gauge fields appear as the emergent phenomenon in the low-energy sector due to the projection of the electronic wavefunctions onto the curved manifold of the Hilbert sub-space. These emergent EMFs play important roles in many places in condensed-matter physics including the quantum Hall effect, strongly correlated electrons and also in non-interacting electron systems. In this paper, we describe the fundamental idea behind it and some of its applications studied recently.

Nagaosa, Naoto; Tokura, Yoshinori

2012-01-01

365

Noise and Bandwidth Measurements Of Diffusion-Cooled Nb Hot-Electron Bolometer Mixers at Frequencies Above the Superconductive Energy Gap  

Microsoft Academic Search

Diffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz frequencies (above the superconductive gap energy). We have measured the IF signal bandwidth at 630 GHz of Nb devices with lengths L = 0.3, 0.2, and 0.1 pm in a quasioptical mixer configuration employing

R. A. Wyss; B. S. Karasik; W. R. McGrath; B. Bumble; H. Leduc

1999-01-01

366

Electromagnetic Hypersensitivity  

Microsoft Academic Search

\\u000a Electromagnetic hypersensitive persons (EHS) attribute their nonspecific health symptoms to environmental electromagnetic\\u000a fields (EMF) of different sources in or outside their homes. In general, causal attribution is not restricted to specific\\u000a EMF frequencies but involves a wide range from extremely low frequencies (ELF) up to radio frequencies (RF) including mobile\\u000a telecommunication microwaves and radar. EHS argue that existing exposure limits

Norbert Leitgeb

367

Evolution of electromagnetic electron holes in the generation process of whistler-mode chorus emissions: A particle simulation study  

NASA Astrophysics Data System (ADS)

Recent particle simulations have successfully reproduced the generation process of whistler-mode rising-tone emissions like chorus emissions [1]. Chorus emissions are interpreted as triggered emissions by a coherent whistler-mode wave excited at a constant frequency via the linear cyclotron resonance instability driven by temperature anisotropy of energetic electrons. By injecting a triggering wave artificially from the magnetic equator, we find that triggering waves with different wave amplitudes result in rising-tone emissions with almost the same frequency sweep rate and saturation level. We find formation of an electron hole in the velocity phase space near the magnetic equator. The electron hole is asymmetric in the phase because of the frequency variation of the triggered emissions, which gives the inhomogeneity ratio S ˜ -0.4 as assumed in the nonlinear wave growth theory [2]. The depletion of resonant electrons due to formation of electron holes moves progressively toward the core part of the distribution function at higher pitch angles. At the large perpendicular velocity, we find formation of an electron island rather than an electron hole. A larger number of resonant electrons are trapped at high perpendicular velocities at some distance away from the equator. Because of the decreasing parallel velocity and the acceleration in the perpendicular direction, the resonant electrons trapped by the wave appear forming an island in the velocity phase space. The trapped electrons receive energy from the wave, while untrapped resonant electrons lose energy to the wave propagating away from the equator. The balance between the electron hole and the electron island in the velocity phase space determines the saturation of chorus emissions. [1] Hikishima, M., Y. Omura, and D. Summers (2010), Self-consistent particle simulation of whistler mode triggered emissions, J. Geophys. Res., 115, A12246, doi:10.1029/2010JA015860. [2] Omura, Y., Y. Katoh, and D. Summers (2008), Theory and simulation of the generation of whistler-mode chorus, J. Geophys. Res., 113, A04223, doi:10.1029/2007JA012622.

Hikishima, M.; Omura, Y.

2011-12-01

368

Introduction to the special issue on high-power electromagnetics (HPEM) and intentional electromagnetic interference (IEMI)  

Microsoft Academic Search

A new threat to civil society has recently emerged. It is known as intentional electromagnetic interference (IEMI) and covers the threat of intense electromagnetic disturbances that may be applied to the sophisticated electronic systems that are so important to our daily lives. This paper provides a brief background for the threat, defines important terms, describes the different types of electromagnetic

William A. Radasky; Carl E. Baum; Manuem W. Wik

2004-01-01

369

Tautomers and electronic states of jet-cooled 2-aminopurine investigated by double resonance spectroscopy and theory.  

PubMed

We present resonant two-photon ionization (R2PI), IR-UV, and UV-UV double resonance spectra of jet-cooled 2-aminopurine (2AP) as well as Fourier transform infrared (FTIR) gas phase spectra. 2AP is a fluorescing isomer of the nucleobase adenine. The results show that there is only one tautomer of 2AP which absorbs in the wavelength range 32,300-34,500 cm(-1). The comparison with the calculated IR spectra of 9H- and 7H-2AP points to 9H-2AP as the dominating tautomer in the gas phase but the spectra are too similar to allow an unambiguous assignment to the respective tautomer. Hence, we determined vertical and adiabatic excitation energies of both tautomers employing combined density functional theory and multi-reference configuration interaction techniques. For the 0-0 band of the first 1pipi* transition of 9H-2AP we obtain a theoretical value of 32,328 cm(-1), in excellent agreement with the band origin of our R2PI spectrum at 32,371 cm(-1). The first singlet pipi* transition of the less stable 7H-2AP tautomer is predicted to be red-shifted by about 1700 cm(-1) with respect to the corresponding transition in 9H-2AP. From the absence of experimental bands in the energy region between 30,300 and 32,350 cm(-1) we conclude that 7H-2AP is not present to an appreciable extent in the molecular beam. Our calculations yield nearly equal energies for the 1npi* and 1pipi* minima of isolated 2AP, similar to the situation in adenine. The hitherto existing argument that the energetic order of states is responsible for the different spectroscopic properties of these isomers therefore does not hold. Rather, vibronic levels close to the origin of the 1pipi* transition cannot access the conical intersection between the 1pipi* and S(0) states along a puckering coordinate of the six-membered ring, in contrast to the situation in electronically excited 9H-adenine. As a consequence, a rich vibrational structure can be observed in the R2PI spectrum of 2AP whereas the spectrum of 9H-adenine breaks off at low energies. PMID:16186905

Seefeld, Kai A; Plützer, Christian; Löwenich, Dennis; Häber, Thomas; Linder, Rolf; Kleinermanns, Karl; Tatchen, Jörg; Marian, Christel M

2005-07-15

370

Electromagnetic Effects in SDF Explosions  

Microsoft Academic Search

The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from

H Reichenbach; P Neuwald; A L Kuhl

2010-01-01

371

High-Resolution Measurements of Electron Temperature, Density, and Width Profiles of 234 Coronal Loops in the Non-Equilibrium Cooling Phase  

NASA Astrophysics Data System (ADS)

We measure the profiles of the electron temperature Te(s), the electron density ne(s), and loop widths w(s) of 234 coronal loops from triple-filter TRACE data. We model also the loop geometry with a semi-circular model in order to measure the unprojected full loop length L and the inclination angle ? of the loop plane to the vertical, which are both required to apply loop scaling laws and hydrodynamic models. The statistics of the measured loop parameters are: electron temperatures Te=1.18±0.30 MK, electron densities ne=10(9.0± 0.2) cm-3, loop widths w=1.44±0.33 Mm, loop lengths L=56± 47 Mm, fraction of detected loop lengths Ldet/L =0.67±0.23, and loop inclination angles |?|=22° ± 18°. From these parameters we determine the average overpressure of these loops with respect to the equilibrium RTV law, q=p/pRTV and find that 86% of the loops exhibit an overpressure (up to q < 30), 9% an underpressure, and only about 5% are consistent with RTV. We interpret the observed overpressure as a natural consequence of the non-equilibrium cooling phase. Applying a non-equilibrium scaling law we predict that the loops were heated to soft X-ray temperatures up to Te < 15 MK prior to their cooling to EUV wavelengths. For the loop lifetimes we find an approximate scaling of ?life ? 10 (L/10 Mm)2 min, with a median lifetime of 7 hours for our sample of TRACE loops. This study postulates a paradigm shift from equilibrium models to non-equilibrium models in the loop cooling phase, which is dominantly observed in EUV wavelengths. This work was supported in part by NASA under the TRACE contract NAS5-38099.

Nightingale, R. W.; Aschwanden, M. J.

2008-05-01

372

Electromagnet Lesson  

NSDL National Science Digital Library

This hands-on classroom activity will help students understand the connections between magnets and electricity generation. The learning cycle planner includes an exploration phase with a hands-on activity and a suggested video. The concept development phase suggests showing the film "Who Killed the Electric Car?" The main part of this learning unit is the electromagnet lesson, which is a two day small group activity in which students will create an electromagnet. This document may be downloaded in PDF file format; student worksheets are included.

Orzali, Joe

2011-12-08

373

Thermal effects on the STAR electromagnetic calorimeter  

SciTech Connect

The STAR detector for the RHIC colliding beam accelerator is under construction at Brookhaven National Laboratory. This detector will consist of a number of subsystems. These include a silicon vertex detector (SVT) for charged particle tracks near the interaction region, a time projection chamber (TPC) for charged particle tracking, an array of plastic scintillation counters (CTB) in a layer around the TPC for triggering on charged particles, a conventional solenoidal magnet, and some additional small triggering detectors along the beam-line. An electromagnetic calorimeter (EMC) is an upgrade to the ``baseline`` detector configuration above. The conventional magnet and numerous electronic channels for the SVT and TPC subsystems will generate a considerable amount of heat during the operation of STAR. However, it is possible that a chiller for the magnet cooling water will not be available during some of the early STAR runs. As a result, the average magnet temperature may vary considerably between winter and summer. This note summarizes calculations and measurements performed to evaluate the effects of an elevated magnet temperature on the performance of the electromagnetic calorimeter.

Fornek, T.; Guarino, V.; Spinka, H.; Underwood, D. [Argonne National Lab., IL (United States). High Energy Physics Div.

1994-07-19

374

Cooling of a multichip electronic module by means of confined two-dimensional jets of dielectric liquid  

SciTech Connect

Experiments were performed to investigate single-phase heat transfer froma smooth 12.7 {times} 12.7 mm{sup 2} simulated chip to a two-dimensional jet of dielectric Fluorinert FC-72 liquid issuing from a thin rectangular slot into a channel confined between the chip surface and nozzle plate. The effects of jet width, confined channel height, and impingement velocity have been examined. Channel height had a negligible effect ont eh theat transfer performance of the jet for the conditions of the present study. A correlation for the convective heat transfer coefficient is presented as a function of jet, width, heat length, flow velocity, and fluid properties. A self-contained multichip cooling module consisting of a 3 {times} 3 array of heat sources confirmed the uniformity and predictability of cooling for each of the nine chips, and proved the cooling module is well suited for packaging large arrays of high-power density chips.

Wadsworth, D.C.; Mudawar, I. (Purdue Univ., West Layfayette, IN (USA))

1990-11-01

375

21 CFR 1000.15 - Examples of electronic products subject to the Radiation Control for Health and Safety Act of 1968.  

Code of Federal Regulations, 2010 CFR

...x-rays and other ionizing electromagnetic radiation, electrons, neutrons...radiation include: Ionizing electromagnetic radiation: Television receivers...radiation and ionizing electromagnetic radiation: Electron...

2009-04-01

376

21 CFR 1000.15 - Examples of electronic products subject to the Radiation Control for Health and Safety Act of 1968.  

Code of Federal Regulations, 2010 CFR

...x-rays and other ionizing electromagnetic radiation, electrons, neutrons...radiation include: Ionizing electromagnetic radiation: Television receivers...radiation and ionizing electromagnetic radiation: Electron...

2010-04-01

377

Electromagnetic radiation and conducted susceptibility diagnosis and analysis of vehicle electronic circuit using mixed-mode S-parameter method  

Microsoft Academic Search

In this paper, the radiated emission and the conducted susceptibility of vehicle electronic circuit to external radio frequency (RF) disturbances are studied using mixed-mode S-parameters method. The analytic method adopting mixed-mode S-parameters developed in this paper can be used to illustrate noise-converting phenomenon and verify successfully by the bulk current injection (BCI) test procedures. The far-field measurement and the susceptible

C.-Y. Ho; C.-H. Huang; T.-S. Horng

2009-01-01

378

Simultaneous observation of caviton formation, spiky turbulence, and electromagnetic radiation  

NASA Astrophysics Data System (ADS)

Formation of density cavities, spiky turbulence, and electromagnetic radiation at the plasma frequency and its harmonics are observed simultaneously in the presence of a cold-electron beam. The electrostatic and electromagnetic frequency spectra evolve with the development of cavities.

Cheung, P. Y.; Wong, A. Y.; Darrow, C. B.; Qian, S. J.

1982-05-01

379

Electromagnetic scattering  

Microsoft Academic Search

This report summarizes research results produced by the investigator under support of the Air Force grant. The work has been mainly concerned with the scattering of electromagnetic waves by bounded bodies of small electrical dimensions, but with some consideration also of acoustic scattering by soft, hard and homogeneous penetrable shapes.

T. B. A. Senior

1983-01-01

380

Electromagnetic Survey  

USGS Multimedia Gallery

USGS hydrologist conducts a broadband electromagnetic survey in New Orleans, Louisiana. The survey was one of several geophysical methods used during USGS applied research on the utility of the multi-channel analysis of surface waves (MASW) seismic method for non-invasive assessment of earthen levee...

2009-05-01

381

Electromagnetic launcher  

Microsoft Academic Search

This paper describes an electromagnetic launcher. It comprises: a stationary superconductive coil situated coaxially in a cylindrical vacuum vessel for providing a magnetic field. The superconductive coil having a central aperture, the vacuum vessel having an axially extending bore passing through the central aperture of the superconducting coil; a resistive coil situated coaxially with the superconductive coil and movable axially

E. T. Laskaris; M. V. K. Chari

1990-01-01

382

Enhancing forced convection heat transfer from multiple protruding heat sources simulating electronic components in a horizontal channel by passive cooling  

Microsoft Academic Search

Experiments were conducted to study forced convection heat transfer in a small aspect ratio of multiple protruding heat sources in a horizontal channel with passive cooling. Perforated holes are arranged in the base of channel in a staggered manner in two rows between heat sources. Due to the increase of temperature between heaters, outside air is withdrawn naturally through the

G. I. Sultan

2000-01-01

383

Three-dimensional electromagnetic strong turbulence: Dependence of the statistics and dynamics of strong turbulence on the electron to ion temperature ratio  

NASA Astrophysics Data System (ADS)

The temperature ratio Ti/Te of ions to electrons affects both the ion-damping rate and the ion-acoustic speed in plasmas. The effects of changing the ion-damping rate and ion-acoustic speed are investigated for electrostatic strong turbulence and electromagnetic strong turbulence in three dimensions. When ion damping is strong, density wells relax in place and act as nucleation sites for the formation of new wave packets. In this case, the density perturbations are primarily density wells supported by the ponderomotive force. For weak ion damping, corresponding to low Ti/Te, ion-acoustic waves are launched radially outwards when wave packets dissipate at burnout, thereby increasing the level of density perturbations in the system and thus raising the level of scattering of Langmuir waves off density perturbations. Density wells no longer relax in place so renucleation at recent collapse sites no longer occurs, instead wave packets form in background low density regions, such as superpositions of troughs of propagating ion-acoustic waves. This transition is found to occur at Ti/Te ~ 0.1. The change in behavior with Ti/Te is shown to change the bulk statistical properties, scaling behavior, spectra, and field statistics of strong turbulence. For Ti/Te>rsim0.1, the electrostatic results approach the predictions of the two-component model of Robinson and Newman, and good agreement is found for Ti/Te>rsim0.15.

Graham, D. B.; Cairns, Iver H.; Skjaeraasen, O.; Robinson, P. A.

2012-02-01

384

Prediction of Elastic Modulus + Anisotropy Using X-Ray and Electron Backscattered Diffraction Texture Quantification and Ultrasonic (Electromagnetic Acoustic Transducer) Measurements in Aluminum Sheets  

NASA Astrophysics Data System (ADS)

Crystallographic texture is generally measured using X-ray diffraction, performed off-line using small samples determining near-surface texture only; electron backscattered diffraction (EBSD) can also be used, but only samples relatively small areas. Ultrasonic methods determine elastic property anisotropy and texture, via orientation distribution coefficients (ODCs), and while there is substantial literature comparing ultrasonically determined properties with X-ray or neutron diffraction texture, there is little discussion about texture inhomogeneity (place to place in a sheet or through thickness) and sampling volume effects (X-ray compared to EBSD) on the accuracy of the correlations. In this article, the crystallographic texture of nominally pure aluminum and commercial aluminum alloy sheets has been determined by X-ray diffraction and EBSD and used to calculate the elastic anisotropy, which is then compared to ultrasonic electromagnetic acoustic transducer (EMAT) velocity anisotropy taking into account through-thickness texture variations. Significant and consistent spatial variability in texture occurs in the aluminum sheet samples (sheet edge to center and through thickness). Predictions of elastic anisotropy based on surface texture determination, as characterized by X-ray diffraction or surface EBSD, gave poor correlations with EMAT velocity anisotropy when the sample contained significant through thickness texture variations; however, accounting for this using multiple EBSD scans through thickness gave good correlations.

Davis, C. L.; Strangwood, M.; Potter, M.; Dixon, S.; Morris, P. F.

2008-03-01

385

The origin of electrons in MALDI and their use for sympathetic cooling of negative ions in FTICR  

Microsoft Academic Search

In MALDI, electrons were found to be formed by the photoelectric effect on the metal\\/organic matrix interface. The thin layer of organic matrix reduces the metal work function, resulting in a high electron yield in a field-free MALDI source. These electrons were detected in a FTICR mass spectrometer indirectly, by the observation of SF6? ions, produced by electron capture. The

Vladimir Frankevich; Richard Knochenmuss; Renato Zenobi

2002-01-01

386

Enhanced Conversion of Thermal Electron Bernstein Waves to the Extraordinary Electromagnetic Mode on the National Spherical Torus Experiment  

SciTech Connect

A fourfold increase in the conversion of thermal electron Bernstein waves ~EBW! to the extraordinary mode (X mode! was measured when the density scale length (Ln) was progressively shortened by a local boron nitride limiter in the scrape-off of an Ohmically heated National Spherical Torus Experiment plasma @M. Ono, S. Kaye, M. Peng et al., Proceedings of the 17th IAEA Fusion Energy Conference ~IAEA, Vienna, 1999!, Vol. 3, p. 1135#. The maximum conversion efficiency approached 50% when Ln was reduced to 0.7 cm, in agreement with theoretical predictions that used locally measured Ln . Calculations indicate that it is possible to establish Ln ,0.3 cm with a local limiter, a value predicted to attain ;100% EBW conversion to the X mode in support of proposed EBW heating and current drive scenarios. 2003 American Institute of Physics. @DOI: 10.1063/1.1564081#

Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Efthimion, P. C. [Princeton Plasma Physics Laboratory (PPPL); Jones, B. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL); Wilgen, John B [ORNL; Bell, Gary L [ORNL; Bigelow, Tim S [ORNL; Maingi, Rajesh [ORNL; Rasmussen, David A [ORNL; Harvey, R. W. [CompX, Del Mar, CA; Smirnov, A. [Moscow State University; Paoletti, F. [Columbia University; Sabbagh, S. A. [Columbia University

2003-01-01

387

Stochastic Cooling  

SciTech Connect

Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

Blaskiewicz, M.

2011-01-01

388

High-Gradient Electromagnetic Separator with Continuous Slurry Extraction.  

National Technical Information Service (NTIS)

This kind of separator is operating without matrix in a cascade arrangement of conventional electromagnets. It is most suitable for continuous extraction of paramagnetic particulate solids in liquid suspensions. The water-cooled coils are supported by an ...

L. Dolle

1986-01-01

389

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Modeling and Computing Example for Effective Electromagnetic Parameters of Multiphase Composite Media  

NASA Astrophysics Data System (ADS)

A method using strong fluctuation theory (SFT) to compute the effective electromagnetic parameters of multiphase composite media, and common materials used to design radar-absorbing materials, is demonstrated. The effective electromagnetic parameters of ultrafine carbonyl-iron (DT-50) and fiber fabric, which are both multiphase composite media and represent coated and structured radar absorbing materials, respectively, are investigated, and the corresponding equations of electromagnetic parameters by using the SFT are attained. Moreover, we design a program to simplify the solutions, and the results are discussed.

Song, Wei-Li; Yuan, Jie; Hou, Zhi-Ling; Cao, Mao-Sheng

2009-05-01

390

Suppressing electromagnetic interference in direct current converters  

Microsoft Academic Search

Since James Clerk Maxwell established the electromagnetic field theory in 1865, multifarious electrical and electronic products have been invented, designed, produced, and widely deployed, such as wireless communication devices, electrical machines and motors. This has profoundly changed our world and our lives. Now we cannot live without electrical products anymore and, thus, we are surrounded with electromagnetic fields generated. On

Hong Li; Zhong Li; Bo Zhang; Wallace Tang; Wolfgang Halang

2009-01-01

391

Electromagnetic leptogenesis  

SciTech Connect

We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP-violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.

Bell, Nicole F.; Law, Sandy S. C. [School of Physics, University of Melbourne, Victoria 3010 (Australia); Kayser, Boris J. [Theoretical Physics Department, Fermilab, PO Box 500, Batavia, Illinois 60510-0500 (United States)

2008-10-15

392

Experimental investigation for enhancement of heat transfer from cooling of electronic components by circular air jet impingement  

NASA Astrophysics Data System (ADS)

An experimental investigation is carried out to study the enhancement of heat transfer from surface of the electronic components by impingement of a circular air jet. Local and stagnation Nusselt number on the impinged surface of the electronic components are presented for different nozzle configurations. Reynolds number, based on nozzle diameter ( d) is varied between 5,500 and 28,500 and nozzle-to-electronic component spacing from 2 to 10 nozzle diameters. The measured data were correlated into a simple equation and compared to the predictions of several other correlations proposed by other researchers. The heat transfer mechanisms involved in the enhanced performance are discussed. The study provides a lot of useful information for the application of impinging jet heat transfer in electronic industry.

Anwarullah, M.; Vasudeva Rao, V.; Sharma, K. V.

2012-09-01

393

Antiproton cooling in the Fermilab Recycler Ring  

SciTech Connect

The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.

Nagaitsev, S.; Bolshakov, A.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M.; Kazakevich, G.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G; Schmidt, C.W.; Seletskiy, S.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; Zenkevich, P.; /Fermilab /Moscow, ITEP /Novosibirsk, IYF /Rochester U.

2005-12-01

394

Antiproton Cooling in the Fermilab Recycler Ring  

SciTech Connect

The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.

Nagaitsev, S.; Broemmelsiek, D.; Burov, A.; Carlson, K.; Gattuso, C.; Hu, M.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G.; Schmidt, C. W.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A. [FNAL, Batavia, IL 60510 (United States); Bolshakov, A.; Zenkevich, P. [ITEP, Moscow, 117259 (Russian Federation); Kazakevich, G. [Budker INP, Novosibirsk, 630090 (Russian Federation)] (and others)

2006-03-20

395

Simulating Electromagnetic Interactions in High Power Density Inverters  

Microsoft Academic Search

In high power density inverters with integrated functions like filters and control electronics electromagnetic interaction between components becomes an important issue. Especially filters for electromagnetic interference are very sensitive to electromagnetic fields and therefore critical to design. Nevertheless only few guidelines for optimizing placement of filter components were published up to now. This paper introduces a simulation method for predicting

E. Hoene; A. Lissner; S. Weber; S. Guttowski; W. John; H. Reichl

2005-01-01

396

Electromagnetic microactuators  

NASA Astrophysics Data System (ADS)

High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.

Büttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.

2013-05-01

397

Electromagnetic strong plasma turbulence  

SciTech Connect

The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.

Melatos, A.; Jenet, F. A.; Robinson, P. A. [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, Texas 78520 (United States); School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

2007-02-15

398

Transient electromagnetic interference in substations  

Microsoft Academic Search

Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulated substations of different voltages. Measurement techniques for recording interference voltages and currents and electric and magnetic fields are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substation control wiring are described using both measurement results

C. M. Wiggins; D. E. Thomas; F. S. Nickel; T. M. Salas; S. E. Wright

1994-01-01

399

Printed Wiring Board for Shielding Electromagnetic Waves.  

National Technical Information Service (NTIS)

Recently, undesired radiation of electromagnetic waves from electronic devices has become a serious problem as the signal speed is increased. For the conventional measures, circuit pattern design, selection of components, shielding, grounding and wiring h...

H. Haniu S. Kubota T. Takatsuji H. Higuchi M. Takamatsu

1989-01-01

400

Electromagnetic Topology: Characterization of Internal Electromagnetic Coupling.  

National Technical Information Service (NTIS)

The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of ...

J. P. Parmantier J. P. Aparicio F. Faure

1991-01-01

401

Natural cooling  

SciTech Connect

With natural cooling, a process or area is cooled by outdoor air when the weather permits, and dependency on mechanical equipment is reduced. It should be used whenever conditions permit, and mechanical equipment should be brought on-line only when natural cooling cannot be employed. The results are minimized costs without lowered comfort or production levels, reduced costs for maintenance associated with higher levels of mechanical chiller system operation, and decreased dependence on expensive, nonrenewable energy sources. This article reviews several methods of natural cooling and provides a detailed computer-based economic evaluation of each. It discusses the air-side economizer, water-side natural cooling, and combination systems.

Fenster, L.C.; Grantier, A.J.

1981-11-25

402

Electromagnetic Transport from Microtearing Mode Turbulence  

SciTech Connect

This Letter presents nonlinear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high-{beta} discharge in the National Spherical Torus Experiment. The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free-streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States); Nevins, W. M.; Wang, E. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Yuh, H. [Nova Photonics Inc., Princeton, New Jersey 08540 (United States)

2011-04-15

403

Electromagnetic Transport From Microtearing Mode Turbulence  

SciTech Connect

This Letter presents non-linear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high beta discharge in the National Spherical Torus Experiment (NSTX). The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

Guttenfelder, W; Kaye, S M; Nevins, W M; Wang, E; Bell, R E; Hammett, G W; LeBlanc, B P; Mikkelsen, D R

2011-03-23

404

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronics Program) in solid state electronics, quantum electronics, information electronics, control and optimization, and electromagnetic phenomena is presented. Results of the research to date are summarize...

M. Tinkham

1991-01-01

405

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronics Program) in solid state electronics, quantum electronics, information electronics, control and optimization, and electromagnetic phenomena is presented. Results of the research to date are summarize...

M. Tinkham

1987-01-01

406

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

This annual report of the JSEP (Joint Services Electronic Program) in solid state electronics, quantum electronics, information electronics, control and optimization, and electromagnetic phenomenon is presented. Results of the research to date are summari...

M. Tinkham

1985-01-01

407

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronic Program) in solid state electronics, quantum electronics, information electronics control and optimization and electromagnetic phenomenon is presented. Results of the research to date are summarized ...

M. Tinkham

1985-01-01

408

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronics Program) in solid state electronics, quantum electronics, information electronics, control and optimization, and electromagnetic phenomena is presented. Results of the research to date are summarize...

M. Tinkham

1986-01-01

409

Electromagnetic topology: Characterization of internal electromagnetic coupling  

Microsoft Academic Search

The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental

J. P. Parmantier; J. P. Aparicio; F. Faure

1991-01-01

410

Electromagnetic topology - Characterization of internal electromagnetic coupling  

Microsoft Academic Search

This paper presents the main principles of a method dealing with the resolution of electromagnetic internal problems: electromagnetic topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of electromagnetic topology. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the

J. P. Parmantier; J. P. Aparicio; F. Faure

1991-01-01

411

Fundamentals of a floating loop concept based on R134a refrigerant cooling of high heat flux electronics  

Microsoft Academic Search

The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has been developing technologies to address the thermal concerns associated with hybrid electric vehicles (HEVs). This work is part of the ongoing FreedomCAR and Vehicle Technologies program (FCVT), performed for the Department of Energy (DOE). Removal of the heat generated from electrical losses in traction motors

C. W. Ayers; J. S. Hsu; K. T. Lowe

2006-01-01

412

Radiation effect and relaxation layer in electro-magnetically driven strong shock waves  

NASA Astrophysics Data System (ADS)

Strong shock waves play a crucial role in many astrophysical phenomena. Ion-electron relaxation process and radiation affect the structure of strong shock waves. Since the non-linear nature of the relaxation process makes the plasma behavior extremely complicated, it requires well-defined shock wave formation to estimate the structure. We investigate electro-magnetically driven shock in laboratory experiments. The pulse power device with tapered electrodes can generate a quasi steady and 1-D shock [1], which allows for analysis of ion-electron relaxation and radiation processes. We will show results of electron temperature measurement by a line pair method and radiative cooling, which restricts the increase of electron temperature. [4pt] [1] K. Kondo, M. Nakajima, T. Kawamura and K. Horioka, Rev. Sci. Instr. 77, 036104 (2006).

Kondo, Kotaro; Nakajima, Mitsuo; Kawamura, Tohru; Horioka, Kazuhiko

2009-11-01

413

Analysis of GPS Total Electron Content (TEC) and Satellite Electromagnetic Data of Atmospheric Processes Related to the Northern Sumatra Earthquake Swarms of Dec 2004-Apr 2005  

NASA Astrophysics Data System (ADS)

This work describes results from our analysis of: (1) GPS Total Electron Content (TEC) measurements collected from ground based stations; (2) ionospheric electromagnetic plasma measurements from the DEMETER satellite; (3) thermal infrared (TIR) data (NOAA/AVHRR, MODIS); (4) emitted long-wavelength radiation (OLR) and; (5) surface latent heat flux (SLHF) from NOAA/NCEP. We found atmospheric and ionospheric anomalies approximately one week prior for both the Dec 26, 2004, M 9.0 Sumatra-Andaman Islands and the March 28, 2005, M 8.7 Northern Sumatra earthquakes. There were 125 earthquakes (M>5.5) in the 118 days of data (December 1, 2004 through April 1, 2005) we analyzed in this region (0°-10°, N and 90°-100° E). Ionospheric variations (GPS/TEC), associated with the Northern Sumatra events, were determined from data of both the regional SuGAr array (13 stations in Indonesia) and four IGS stations. For each station a time series of the vertical TEC (VTEC) data were computed and compared with the magnetic Dst index, to see if these signals were the result of external magnetic field activity. On December 22, four days prior to the M9.0 quake, GPS/TEC data reached a monthly maximum with low Dst values. For the M 8.7 March 28 earthquake values of GPS/TEC were observed to increase four days (March 22-25) prior to the event again with low Dst values. The VLF/ICE instrument on DEMETER was operational during the M 8.7 earthquake of March 28, 2005. Our analysis shows intensive ELF emissions within the 0 -200 Hz window at the conjugated points on 22 of March, 2005, 6 days before the earthquake during DEMETERs close proximity to the epicenter. In the case of the Dec 26, 2004, M 9.0 quake, OLR data were >80 W/m2, corresponding to approximately two sigma above the mean for the months of December, between 2001 and 2004, were found on December 21, 2004, five days before the event. Anomalous values of SLHF associated with the M9.0 Sumatra-Andaman Islands earthquake event were found on Dec 7, 2005 (above five sigma) and Dec 22, 2005 (SLHF +280Wm2). Smaller anomalies are also seen on Mar 23, 2005 (SLHF +180Wm2). The anomalies consistently occur over regions of maximum stress (along continental boundaries), and appear not to be atmospheric due to the long persistence over the same region.

Ouzounov, D.; Pulinets, S.; Ciraolo, L.; Cervone, G.; Kafatos, M.; Taylor, P.; Parrot, M.; Li, F.; Hattori, K.

2006-12-01

414

The Electronic Spectra of the Jet-Cooled Boron Difluoride (BF_2) and Boron Dichloride (BCl_2) Free Radicals  

NASA Astrophysics Data System (ADS)

Laser-induced fluorescence (LIF) and single vibronic level (SVL) emission spectra of the Ã^{2}?_u-X˜^{2}A_1 transitions of the jet-cooled boron difluoride (BF_2) and boron dichloride (BCl_2) radicals have been observed. In each case, the radical was produced in a pulsed discharge jet using a precursor mixture of the corresponding boron halide (BF_3 or BCl_3) in high pressure argon. Due to a large change in geometry from a bent ground state to a linear excited state, the LIF spectra are very extensive and the emission spectra show long bending progressions. Strong LIF bands of ^{11}BF_2 and ^{10}BF_2 (from isotopically enriched ^{10}BF_3) were observed in the 29200-35100 cm^{-1} region and isotope shifts were identified. The rotational constants obtained from high resolution LIF spectra of the two isotopologues were used to determine the effective zero-point structure of the ground state. For BCl_2, weaker and much more complex LIF spectra, which have as yet defied vibrational analysis, were recorded in the 15300-22700 cm^{-1} region. SVL emission spectra of five isotopologues have been obtained, affording a detailed vibrational analysis of the ground state of BCl_2.

Yang, Jie; Wei, Jie; Sunahori, Fumie; Gharaibeh, Mohammed; Ellis, Blaine; Chen, Alfred; Clouthier, Dennis J.; He, Sheng-Gui

2009-06-01

415

a Spectroscopic Study of the Linear-Bent Electronic Transitions of Jet-Cooled BCl_2 and HBCl  

NASA Astrophysics Data System (ADS)

Laser induced fluorescence (LIF) and single vibronic level emission spectra (SVL) of jet-cooled BCl_2 and HBCl have been measured. The radicals were produced in a pulsed electric discharge of a mixture of BCl_3/Ar and BCl_3/H_2/Ar, respectively. The LIF spectra of both radicals are congested due to overlapping bands from the boron and chlorine isotopes. In addition, the ground and first excited states are the two Renner-Teller components of a ^2? state split by a strong vibronic interaction. The Franck-Condon profile of the tilde{A}^2B_1 - tilde{X}^2A_1 band system of BCl_2 and the tilde{A}^2A'' - tilde{X}^2A' system of HBCl are characteristic of linear-bent excitations. Excited state bending progressions have been identified in both species using the LIF-sync scan procedure in which the monochromator is offset by a value corresponding to a ground state fundamental frequency of the target molecule and scanned simultaneously with the dye laser. LIF spectra of individual isotopes can thus be recorded. Ground state vibrational frequencies have been deduced from SVL spectra. The emission spectra for BCl_2, are dominated by progressions in the symmetric stretching (?_1) and bending (?_2) modes. In the case of HBCl, progressions in the bending (?_2) and BCl stretching (?_3) modes were observed.

Nagarajan, Ramya; Yang, Jie; Clouthier, Dennis J.

2011-06-01

416

Corrosion study of heat exchanger tubes in pressurized water cooled nuclear reactors by conversion electron Mössbauer spectroscopy  

Microsoft Academic Search

57Fe-conversion electron Mössbauer spectroscopy (CEMS) — a sensitive tool to analyze the phase composition of corrosion products\\u000a on the surface of stainless steel — was applied to study real specimens from the Paks Nuclear Power Plant, Hungary. The primary\\u000a circuit side of the heat exchanger tubes was studied on selected samples cut out from the steam generators during regular\\u000a maintenance.

Z. Homonnay; P. Á. Szilágyi; E. Kuzmann; K. Varga; Z. Németh; A. Szabó; K. Radó; J. Schunk; P. Tilky; G. Patek

2007-01-01

417

A New Technology for Negative Ion Detection and the Rapid Electron Cooling in a Pulsed High-Density Etching Plasma  

Microsoft Academic Search

Time-resolved measurements of key parameters in an inductively-coupled pulsed discharge in chlorine are carried out to elucidate a feature of pulsed plasma etching. Langmuir probe diagnostics in the afterglow phase show a very fast decrease in the electron temperature from 3.5 eV to 0.8 eV within 10 µs, along with a plasma potential drop from 22 V to 5 V.

Tae Hyuk Ahn; Keiji Nakamura; Hideo Sugai

1995-01-01

418

Electromagnetic interference reduction using electromagnetic bandgap structures in packages, enclosures, cavities, and antennas  

Microsoft Academic Search

Electromagnetic interference (EMI) is a source of noise problems in electronic devices. The EMI is attributed to coupling between sources of radiation and components placed in the same media such as package or chassis. This coupling can be either through conducting currents or through radiation. The radiation of electromagnetic (EM) fields is supported by surface currents. Thus, minimizing these surface

Baharak Mohajer Iravani

2007-01-01

419

Narrow field electromagnetic sensor system and method  

DOEpatents

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

McEwan, T.E.

1996-11-19

420

Narrow field electromagnetic sensor system and method  

DOEpatents

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

421

Cooling a quantum circuit via coupling to a multiqubit system  

SciTech Connect

The cooling effects of a quantum LC circuit coupled inductively with an ensemble of artificial qubits are investigated. The particles may decay independently or collectively through their interaction with the environmental vacuum electromagnetic field reservoir. For appropriate bath temperatures and the resonator's quality factors, we demonstrate an effective cooling well below the thermal background. In particular, we found that for larger samples the cooling efficiency is better for independent qubits. However, the cooling process can be faster for collectively interacting particles.

Macovei, Mihai A. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

2010-04-15

422

Precision Experiments With Stored And Cooled Highly Charged Ions  

SciTech Connect

Accumulation, storing and cooling techniques play an increasingly important role in many areas of science. These procedures can be applied in Penning traps and storage rings to ions. In this way, quantum electrodynamics can be tested in extreme electromagnetic fields by measuring hyperfine structure splittings. Lamb shifts, or g-factors in hydrogen-like heavy systems such as U91+ or Pb81+. In addition, fundamental constants or nuclear properties like the atomic mass can be determined. In the case of a radioactive ion, the fate of an individual ion, undergoing a nuclear decay, can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Presently, the Highly-charged Ion TRAP (HITRAP) facility is being built up at GSI. Stable or radioactive highly charged ions are produced by colliding relativistic ions with a target. After electron cooling and deceleration in the storage ring ESR at GSI, these ions are ejected, decelerated further, and injected into a Penning trap where cooling to 4 K takes place. From there, the cooled highly charged ions such as hydrogen-like uranium are transferred at low energy to different experimental set-ups which are being built up by the international HITRAP Collaboration.

Kluge, H.-Juergen [Gesellschaft fuer Schwerionenforschung (GSI) Planckstrasse 1, D-64291 Darmstadt (Germany); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

2006-11-07

423

Cooling wall  

SciTech Connect

Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.

Nosenko, V.I. [Triangle Trading and Technology Corp., Laguna Hills, CA (United States)

1995-07-01

424

Colouring cryo-cooled crystals: online microspectrophotometry  

PubMed Central

X-rays can produce a high concentration of radicals within cryo-cooled macromolecular crystals. Some radicals have large extinction coefficients in the visible (VIS) range of the electromagnetic spectrum, and can be observed optically and spectrally. An online microspectrophotometer with high temporal resolution has been constructed that is capable of measuring UV/VIS absorption spectra (200–1100?nm) during X-ray data collection. The typical X-ray-induced blue colour that is characteristic of a wide range of cryo-conditions has been identified as trapped solvated electrons. Disulphide-containing proteins are shown to form disulphide radicals at millimolar concentrations, with absorption maxima around 400?nm. The solvated electrons and the disulphide radicals seem to have a lifetime in the range of seconds up to minutes at 100?K. The temperature dependence of the kinetics of X-ray-induced radical formation is different for the solvated electrons compared with the disulphide radicals. The online microspectrophotometer provides a technique complementary to X-ray diffraction for analysing and characterizing intermediates and redox states of proteins and enzymes.

McGeehan, John; Ravelli, Raimond B. G.; Murray, James W.; Owen, Robin Leslie; Cipriani, Florent; McSweeney, Sean; Weik, Martin; Garman, Elspeth F.

2009-01-01

425

k-space drift due to the density variation as a cause of electromagnetic emission generation of type III solar radio bursts by a non-gyrotropic electron beam  

NASA Astrophysics Data System (ADS)

It is widely accepted that there is a correlation between super-thermal electron beams and type III solar radio bursts. Whilst the correlation is an established fact, the actual mechanism that generates the type III burst emission is not yet fully determined. The main source of the uncertainty is current inability to send in-situ probes at distances 0.15 - 1.5Rsun from the solar surface (photosphere). The most widely accepted mechanism, that historically appeared first is the plasma emission. In plasma emission mechanism quasilinear theory, kinetic Fokker-Planck type equation for describing the dynamics of an electron beam is used, in conjunction with the spectral energy density evolutionary equations for Langmuir and ion-sound waves. Further, non-linear wave-wave interactions between Langmuir, ion-acoustic and EM waves produce emission at electron plasma frequency, ?pe or the second harmonic, 2?pe. A variant of the plasma emission mechanism is the stochastic growth theory, where density irregularities produce a random growth, in such a way that Langmuir waves are generated stochastically and quasilinear interactions within the Langmuir clumps cause the beam to fluctuate about marginal stability. The latter models have been used for producing the solar type III burst observable parameters. Other possible mechanisms include: linear mode conversion, antenna radiation and non-gyrotropic electron beam emission [1]. Recent works [2,3] elucidated further the non-gyrotropic electron beam emission, first proposed in Ref.[1]. In particular, the effect of electron beam pitch angle and density gradient on solar type III radio bursts was studied [2] and the role of electron cyclotron maser (ECM) emission with a possible mode coupling to the z-mode was explored [3]. In this contribution and paper [4], using large-scale Particle-In-Cell simulations, we explore the non-gyrotropic electron beam emission mechanism by studying the effects of electron beam kinetics and k-space drift, in long term evolution of electromagnetic emission generation of type III solar radio bursts. The following improvements and progress in understanding of the radio emission mechanism are made: (i) Improved numerical simulations with larger spatial domain and longer end-simulation times; (ii) The electron beam injection on a density plateau followed by a decreasing density gradient that mimics the Sun-earth system; (iii) Consideration of a ring and shifted ring electron initial velocity distribution functions; (iv) The role of the k-space drift in the radio emission; (v) Estimation of the ECM growth rate and its role in the emission generation. It is worthwhile to note that Ref.[3] proposed mode coupling on the density gradient as a source of radio emission as opposed to the k-space drift advocated in the present work. The situation is analogous to the auroral waves emitted near the plasma frequency in Earth auroral ionosphere [A. Layden, I. H. Cairns, P. A. Robinson, and J. LaBelle, J. Geophys. Res. 116, A12328 (2011)]. [1] D. Tsiklauri, "An alternative to the plasma emission model: Particle-In-Cell, self-consistent electromagnetic wave emission simulations of solar type III radio bursts", Physics of Plasmas 18, 052903 (2011) [2] R. Pechhacker, D. Tsiklauri, "The effect of electron beam pitch angle and density gradient on solar type III radio bursts", Phys. Plasmas 19, 112903 (2012) [3] R. Pechhacker, D. Tsiklauri, "Electron cyclotron maser emission mode coupling to the z-mode on a longitudinal density gradient in the context of solar type III bursts", Phys. Plasmas 19, 110702 (2012) [4] H. Schmitz, D. Tsiklauri, "k-space drift due to the density variation as a cause of electromagnetic emission generation of type III solar radio bursts by a non-gyrotropic electron beam", Phys. Plasmas, in preparation, (2013)

Tsiklauri, David; Schmitz, Holger

2013-04-01

426

Beam cooling: Principles and achievements  

SciTech Connect

After a discussion of Liouville's theorem, and its implications for beam cooling, a brief description is given of each of the various methods of beam cooling: stochastic, electron, radiation, laser, ionization, etc. For each, we present the type of particle for which it is appropriate, its range of applicability, and the currently achieved degree of cooling. For each method we also discuss the present applications and, also, possible future developments and further applications.

Mohl, Dieter; Sessler, Andrew M.

2003-05-18

427

Cool Shelter  

ERIC Educational Resources Information Center

|Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from…

Praeger, Charles E.

2005-01-01

428

Cool Shelter  

ERIC Educational Resources Information Center

Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from collecting…

Praeger, Charles E.

2005-01-01

429

Particle acceleration by electromagnetic waves.  

PubMed

We consider the symmetry in the interaction of photons and electrons, which has led to a common description of electron and photon accelerations; effects such as photon Landau damping arise naturally from such a treatment. Intense electromagnetic waves can act as a photon mirror to charged particles. The subsequent acceleration is equivalent to the photon pulse accelerating electrons. During the interaction or reflection process, the charged particle can emit bursts of radiation similar to the radiation emitted from the particles during wave breaking of plasma waves. PMID:18218605

Bingham, R

2008-05-28

430

Energy efficient liquid cooling  

Microsoft Academic Search

The theme of this paper is an investigation of the hydrodynamic performance of liquid pumps for electronics cooling applications, considered in conjunction with a range of primary heat exchangers. Pressure-flow characteristics of a set of geometrically- similar, miniature-scale centrifugal pumps are measured, and reductions in hydrodynamic efficiency are seen to occur below a critical Reynolds number. Six primary heat exchangers

Jeff Punch

2008-01-01

431

Gas turbine engine component cooling system  

SciTech Connect

An electronic control apparatus is described which is positionable in a cooling fluid environment comprising: a housing for containing an electronic control having an outer surface; a plurality of heat transfer fins extending from the outer surface of the housing and positionable in the cooling fluid environment for cooling the fins and housing; environmental sensor means disposed in and connected to the housing adjacent to the heat transfer fins and being connectible to the electronic control; and the sensor means being positioned in the housing in flow communication with the cooling fluid flowable over the fins for sensing a characteristic of primarily the cooling fluid environment.

Colman, M.E.; Goeller, R.E.

1986-07-22

432

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronics Program) in Electromagnetics, Quantum Electronics, Solid State Electronics, Materials and Devices and Information System is presented. In addition, results of the research to date are summarized and...

W. G. Oldham

1986-01-01

433

Electromagnetic Spectrum from QGP Fluid  

Microsoft Academic Search

We calculate thermal photon and electron pairdistribution from hot QCD matter produced in high energy heavy-ion collisions, based on a hydrodynamical model which is so tuned as to reproduce the recent experimental data at CERN SPS, and compare these electromagnetic spectra with experimental data given by CERN WA80 and CERES. We investigate mainly the effects of the off-shell properties of

Tetsufumi Hirano; Shin Muroya; Mikio Namiki

1997-01-01

434

Electromagnetic Pulse Rotary Seal.  

National Technical Information Service (NTIS)

An rotary seal for protection against electromagnetic interference and electromagnetic pulses is disclosed. An electrically conductive resilient bellows surrounds a shaft extending through an opening in an enclosure. The bellows is attached at one end to ...

C. W. Neher

1987-01-01

435

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This web site contains materials about all parts of the electromagnetic spectrum. It describes each space telescope that NASA has launched as well as its observing range in the electromagnetic spectrum.

Astrophysics, Laboratory F.

2004-11-17

436

The Electromagnetic Spectrum: FRONTLINE  

NSDL National Science Digital Library

This video segment adapted from FRONTLINE introduces the electromagnetic spectrum and explains how the various types of electromagnetic waves are distinguished by the amount of energy each wave carries.

Foundation, Wgbh E.

2004-02-20

437

CONTINUUM ELECTROMAGNETIC RADIATION FROM SOLAR FLARES  

Microsoft Academic Search

Continuum electromagnetic radiation from solar flares is discussed in ; terms of the energy loss processes of electrons in the solar atmosphere. It is ; shown that it is possible to attribute the continuum radiation both at radio ; frequencies and at visible frequencies to synchrotron radiation by exponential ; rigidity distributions of electrons. (auth);

W. A. Stein; E. P. Ney

1963-01-01

438

Electromagnetic remote sensing. Low frequency electromagnetics  

NASA Astrophysics Data System (ADS)

A series of lectures are presented on the topic of the location and identification of compact objects by low frequency electromagnetics. These lectures were presented as a portion of two graduate level courses in electrical engineering at the University of Toronto in 1985 and 1987. Magnetostatics, electrostatics and electromagnetic induction techniques are discussed in detail.

McFee, John E.

1989-01-01

439

Electromagnetic Interference (Emi)  

Microsoft Academic Search

\\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at

Mike Hardage; Philip D. Henry

440

Composite electromagnetic pulse threat  

Microsoft Academic Search

A new electromagnetic pulse threat based on a composite ambient field defined by a combination of lightning, NEMP (nuclear electromagnetic pulse) and microwave threats is discussed. The composite electromagnetic pulse threat has been used to harden a military helicopter. The hardening to a composite threat resulted in the development of simplified hardening verification procedures. It also provided an economical advantage

A. S. Podgorski

1990-01-01

441

Composite electromagnetic pulse threat  

Microsoft Academic Search

A new electromagnetic pulse threat that is based on a composite ambient field defined by a combination of lightning, NEMP (nuclear electromagnetic pulse) and microwave threats is discussed. The composite electromagnetic pulse threat has been used to harden a military helicopter. The hardening to a composite threat resulted in the development of simplified hardening verification procedures. It also provided an

Andrew S. Podgorski

1990-01-01

442

Nonlinear electromagnetic wave equations for superdense magnetized plasmas  

SciTech Connect

By using the quantum hydrodynamic and Maxwell equations, we derive the generalized nonlinear electron magnetohydrodynamic, the generalized nonlinear Hall-MHD (HMHD), and the generalized nonlinear dust HMHD equations in a self-gravitating dense magnetoplasma. Our nonlinear equations include the self-gravitating, the electromagnetic, the quantum statistical electron pressure, as well as the quantum electron tunneling and electron spin forces. They are useful for investigating a number of wave phenomena including linear and nonlinear electromagnetic waves, as well as three-dimensional electromagnetic wave turbulence spectra and structures arising from mode coupling processes at nanoscales in dense quantum magnetoplasmas.

Shukla, Nitin; Brodin, G.; Marklund, M.; Shukla, P. K.; Stenflo, L. [Department of Physics, Umeaa University, Umeaa SE-90187 (Sweden)

2009-07-15

443

Electromagnetic vibration process for producing bulk metallic glasses.  

PubMed

It is known that the cooling rate from the liquid state is an important factor in the production of bulk metallic glasses. However, the effects of other factors such as electric and magnetic fields have not been thoroughly investigated. Here, we present a new method for producing bulk metallic glasses by using electromagnetic vibrations with simultaneous imposition of an alternating electric current and a magnetic field. This method was found to be effective in enhancing apparent glass-forming ability in Mg65-Cu25-Y10 (atomic percent) alloys. Indeed, larger bulk metallic glasses could be obtained by the electromagnetic vibration process under the same cooling conditions. We presume that disappearance or decrement of clusters by the electromagnetic vibrations applied to the liquid state cause suppression of crystal nucleation. This electromagnetic vibration process should be effective in other bulk metallic glass systems if the clusters in the liquid state cause the crystal nucleation. PMID:15750599

Tamura, Takuya; Amiya, Kenji; Rachmat, Rudi S; Mizutani, Yoshiki; Miwa, Kenji

2005-04-01

444

Electromagnetic vibration process for producing bulk metallic glasses  

NASA Astrophysics Data System (ADS)

It is known that the cooling rate from the liquid state is an important factor in the production of bulk metallic glasses. However, the effects of other factors such as electric and magnetic fields have not been thoroughly investigated. Here, we present a new method for producing bulk metallic glasses by using electromagnetic vibrations with simultaneous imposition of an alternating electric current and a magnetic field. This method was found to be effective in enhancing apparent glass-forming ability in Mg65-Cu25-Y10 (atomic percent) alloys. Indeed, larger bulk metallic glasses could be obtained by the electromagnetic vibration process under the same cooling conditions. We presume that disappearance or decrement of clusters by the electromagnetic vibrations applied to the liquid state cause suppression of crystal nucleation. This electromagnetic vibration process should be effective in other bulk metallic glass systems if the clusters in the liquid state cause the crystal nucleation.

Tamura, Takuya; Amiya, Kenji; Rachmat, Rudi S.; Mizutani, Yoshiki; Miwa, Kenji

2005-04-01

445

Electromagnetically driven dwarf tornados in turbulent convection  

NASA Astrophysics Data System (ADS)

Motivated by the concept of interdependency of turbulent flow and electromagnetic fields inside the spiraling galaxies, we explored the possibilities of generating a localized Lorentz force that will produce a three-dimensional swirling flow in weakly conductive fluids. Multiple vortical flow patterns were generated by combining arrays of permanent magnets and electrodes with supplied dc current. This concept was numerically simulated and applied to affect natural convection flow, turbulence, and heat transfer inside a rectangular enclosure heated from below and cooled from above over a range of Rayleigh numbers (104<=Ra<=5×109). The large-eddy simulations revealed that for low- and intermediate-values of Ra, the heat transfer was increased more than five times when an electromagnetic forcing was activated. In contrast to the generally accepted view that electromagnetic forcing will suppress velocity fluctuations and will increase anisotropy of turbulence, we demonstrated that localized forcing can enhance turbulence isotropy of thermal convection compared to its neutral state.

Kenjereš, Saša

2011-01-01

446

An Assessment of Hazards Caused by Electromagnetic Interaction on Humans Present near Short-Wave Physiotherapeutic Devices of Various Types Including Hazards for Users of Electronic Active Implantable Medical Devices (AIMD)  

PubMed Central

Leakage of electromagnetic fields (EMF) from short-wave radiofrequency physiotherapeutic diathermies (SWDs) may cause health and safety hazards affecting unintentionally exposed workers (W) or general public (GP) members (assisting patient exposed during treatment or presenting there for other reasons). Increasing use of electronic active implantable medical devices (AIMDs), by patients, attendants, and workers, needs attention because dysfunctions of these devices may be caused by electromagnetic interactions. EMF emitted by 12 SWDs (with capacitive or inductive applicators) were assessed following international guidelines on protection against EMF exposure (International Commission on Nonionizing Radiation Protection for GP and W, new European directive 2013/35/EU for W, European Recommendation for GP, and European Standard EN 50527-1 for AIMD users). Direct EMF hazards for humans near inductive applicators were identified at a distance not exceeding 45?cm for W or 62?cm for GP, but for AIMD users up to 90?cm (twice longer than that for W and 50% longer than that for GP because EMF is pulsed modulated). Near capacitive applicators emitting continuous wave, the corresponding distances were: 120?cm for W or 150?cm for both—GP or AIMD users. This assessment does not cover patients who undergo SWD treatment (but it is usually recommended for AIMD users to be careful with EMF treatment).

Gryz, Krzysztof

2013-01-01

447

Quantum states and linear response in dc and electromagnetic fields for the charge current and spin polarization of electrons at the Bi/Si interface with the giant spin-orbit coupling  

SciTech Connect

An expansion of the nearly free-electron model constructed by Frantzeskakis, Pons, and Grioni [1] describing quantum states at the Bi/Si(111) interface with the giant spin-orbit coupling is developed and applied for the band structure and spin polarization calculation, as well as for the linear response analysis of the charge current and induced spin caused by a dc field and by electromagnetic radiation. It is found that the large spin-orbit coupling in this system may allow resolving the spin-dependent properties even at room temperature and at a realistic collision rate. The geometry of the atomic lattice combined with spin-orbit coupling leads to an anisotropic response for both the current and spin components related to the orientation of the external field. The in-plane dc electric field produces only the in-plane components of spin in the sample, while both the in-plane and out-of-plane spin components can be excited by normally propagating electromagnetic wave with different polarizations.

Khomitsky, D. V., E-mail: khomitsky@phys.unn.ru [Lobachevskii State University of Nizhni Novgorod (Russian Federation)

2012-05-15

448

Cooling Off  

NSDL National Science Digital Library

In this activity, learners are introduced to challenges of maintaining temperatures while living in space. Thinking and acting like scientists and engineers, learners experiment to learn how to measure the specific heat capacity (or simply, specific heat) of water and then design an improved cooling system like those used in spacesuits. This lesson is developed using a 5E model of learning. In the ENGAGE section of the lesson, learners look at NASA technology and its relationship to improvements in athletic clothing and equipment. They learn about technology in spacesuit design and the use of this technology in everyday life. Working in teams, students conduct experiments relating to specific heat capacity on a cooling system they design in the EXPLORE and EXPLAIN sections. They are challenged to improve the cooling system in the EXTEND section of this lesson. Learners assess their understanding and abilities throughout the lesson and revisit the Essential Questions during the EVALUATE section.

Nasa

2012-08-06

449

Cooled Heavy Ions in the Storage Ring ESR  

SciTech Connect

The ESR storage ring is equipped with stochastic and electron cooling. Electron cooling is the standard method for most internal experiments with stored heavy ion or rare isotope beams covering a wide energy range. Stochastic cooling is mainly used as a pre-cooling method for hot beams. The combination of both methods allows a considerable reduction of the total cooling time, which is particularly important for experiments with short-lived radioactive ions. At low beam intensity electron cooling results in extremely cold beams which show clear evidence for ordering in a linear string-like structure. A special ion optical mode of the ESR reduces the transition energy to {gamma}t = 1.37, thus the behavior of cooled beams above transition energy can be studied. Laser cooling of a C3+ beam of velocity {beta} = 0.47 is being developed employing electron cooling as a pre-cooling method.

Steck, M.; Beckert, K.; Beller, P.; Franzke, B.; Nolden, F. [GSI Darmstadt, Planckstr. 1, D-64291 Darmstadt (Germany)

2005-06-08

450

Jet-cooled fluorescence excitation spectra, conformation, and carbonyl wagging potential energy function of cyclopentanone and its deuterated isotopomers in the S1 (n,pi *) electronic excited states  

Microsoft Academic Search

The jet-cooled fluorescence excitation spectra of cyclopentanone and its 2,2,5,5-d4 isotopomer have been recorded in the 305–335 nm region. In addition, the spectra of d1, d2, and d3 species were obtained from isotopic mixtures. The electronic band origin of the d0 molecule for the S1 (n,?*) state of A2 symmetry occurs at 30 276 cm?1, while that of the d4

Jian Zhang; Whe-Yi Chiang; Jaan Laane

1993-01-01

451

Jet-cooled fluorescence excitation spectrum, carbonyl wagging, and ring-puckering potential energy functions of 3-cyclopenten-1-one in its S1(n,pi *) electronic excited state  

Microsoft Academic Search

The jet-cooled fluorescence excitation spectrum of 3-cyclopenten-1-one has been recorded in the 308–330 nm region, and the electronic origin for the S1(n,?*) state of A2 symmetry was observed at 30 229 cm?1. The observed spectrum consists of more than 80 bands involving primarily ?3 (carbonyl stretch), ?29 (carbonyl out-of-plane wagging), and ?30 (ring puckering). Bands were also assigned to combinations

Paul Sagear; Jaan Laane

1995-01-01

452

Fundamental issues in general relativity: Inertia, gravitation and electromagnetic mass  

NASA Astrophysics Data System (ADS)

An opportunity for revealing the nature of inertia and gravitation in terms of both general relativity and the electromagnetic mass theory may have been missed in the first quarter of this century. If the entire mass of an elementary charged particle is regarded as electromagnetic in origin, a hypothesis providing a consistent explanation of inertial and gravitational phenomena emerges. Due to the anisotropy in the propagation of electromagnetic interaction in the vicinity of all (massive) objects the electric field of an electron at rest on the Earth's surface is distorted which gives rise to an electric self-force trying to force the electron to move downwards (hence the passive gravitational mass turns out to be electromagnetic); the anisotropy is compensated if the electron is falling with an acceleration g-in this case its electric field is the Coulomb field and the electron's motion is geodesic (non-resistant) in accordance with general relativity. The behaviour of an electron in an accelerated reference frame is identical (the anisotropy in the speed of light in this case is caused by the frame's accelerated motion). This hypothesis can be experimentally tested and opens up the possibility of (at least partly) controlling inertia and gravitation. Even if one insists on the present understanding that only part of the electron mass is electromagnetic it still follows that the possibility for (partly) controlling inertia and gravitation and for an experimental test has been present since the beginning of this century when the electromagnetic mass theory was proposed. It has not been realized up to now that it immediately follows from this theory that part of the electron's active gravitational mass is electromagnetic in origin too which means that part of its gravity being caused by its charge (since part of its active gravitational mass itself is electromagnetic) is also electromagnetic in nature. And if we can control other electromagnetic phenomena nothing in principle prevents us from doing so to inertia and gravitation as well.

Petkov, Vesselin P.

1998-12-01

453

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-04-01

454

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-02-25

455

A high resolution electromagnetic calorimeter based on lead-tungstate crystals  

NASA Astrophysics Data System (ADS)

A large-scale prototype of the PHOS electromagnetic spectrometer, which is part of the ALICE detector, has been built and tested. This prototype has 256 detector channels and is operated at -25 °C. Each detector channel is a lead-tungstate crystal coupled to an Avalanche Photo-Diode with a low-noise preamplifier. The prototype includes a 16×16 crystal matrix, photo-detectors, analog and digital electronics, a thermo-stabilized cooling system, a light-emitting diode monitoring system, and a charged-particle detector acting as veto counter. Results of measurements using electron and hadron beams of the CERN PS and SPS accelerators are discussed, and the performance of the prototype is evaluated.

Aleksandrov, D. V.; Burachas, S. F.; Ippolitov, M. S.; Lebedev, V. A.; Manko, V. I.; Nikulin, S. A.; Nyanin, A. S.; Sibiriak, I. G.; Tsvetkov, A. A.; Vasiliev, A. A.; Vinogradov, A. A.; Bogolyubsky, M. Yu.; Kharlov, Yu. V.; Konstantinov, S. A.; Petrov, V. S.; Polishchuk, B. V.; Sadovsky, S. A.; Senko, V. A.; Soloviev, A. S.; Victorov, V. A.; Vodopianov, A. S.; Nomokonov, P. V.; Basmanov, V. F.; Budnikov, D. V.; Ilkaev, R. I.; Kuryakin, A. V.; Nazarenko, S. T.; Punin, V. T.; Vinogradov, Yu. I.; Delagrange, H.; Schutz, Y.; Balbestre, G. C.; Diaz, J.; Klovning, A.; Mæland, O.; Odland, O. H.; Pommersche, B.; Röhrich, D.; Yin, Z.; Skaali, B.; Wormald, D.; Mares, J. A.; Polak, K.; Deloff, A.; Dobrowolski, T.; Karpio, K.; Kozlowski, M.; Redlich, K.; Siemiarczuk, T.; Stefanek, G.; Tykarski, L.; Wilk, G.; Sugitate, T.; Shigaki, K.; Kohara, R.

2005-09-01

456

Compton Sources of Electromagnetic Radiation  

SciTech Connect

When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.

Geoffrey Krafft,Gerd Priebe

2011-01-01

457

Numerical and experimental thermal characterization of a liquid cooled AlSiC power electronics base plate with integral pin fins  

Microsoft Academic Search

In this study, we present the thermal analysis and experimental performance assessment of an aluminum silicon carbide (AlSiC) metal matrix composite (MMC) base plate with integral cooling fins. By attaching a pin-finned base plate to an open-chambered flow-through heat sink, the mechanical interface between the base plate and cooling medium is eliminated. This reduces the overall thermal resistance and improves

Kevin A. Moores; Yogendra K. Joshi; Gerhard Schiroky

2000-01-01

458

Electromagnetic cellular interactions.  

PubMed

Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating. PMID:20674588

Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

2010-07-30

459

1. Broadband Electromagnetic-Field Sensors with Optoelectronic Links  

Microsoft Academic Search

In this paper, we review the system design, antenna structures, and optoelectronic components that can be used to accurately measure electromagnetic (EM) fields at frequencies up to 100 GHz, in support of the technologies of telecommunications, materials processing, health services, and defense. In addition, electromagnetic compatibility and interference (EMC\\/EMI) in the electronics that support these and other technologies can result

Keith D. Masterson; Motohisa Kanda; David R. Novotny

460

Measurement of the Proton Electromagnetic Form Factor Ratio at Blast  

Microsoft Academic Search

The proton's electromagnetic form factors are fundamental quantities related to its underlying electromagnetic structure. Recent measurements of the form factor ratio from recoil proton polarization experiments at JLab indicate a striking departure from previous measurements above Q2 ≈ 1 GeV2. The unique capabilities of the BLAST detector with a polarized internal hydrogen gas target in a polarized electron storage ring

J. Seely; B. Clasie; C. Crawford; D. Dutta; H. Gao; H. Kolster; J. R. Calarco

2003-01-01