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Sample records for high-current microwave ion

  1. High current ion sources

    International Nuclear Information System (INIS)

    Brown, I.G.

    1989-06-01

    The concept of high current ion source is both relative and evolutionary. Within the domain of one particular kind of ion source technology a current of microamperers might be 'high', while in another area a current of 10 Amperes could 'low'. Even within the domain of a single ion source type, what is considered high current performance today is routinely eclipsed by better performance and higher current output within a short period of time. Within their fields of application, there is a large number of kinds of ion sources that can justifiably be called high current. Thus, as a very limited example only, PIGs, Freemen sources, ECR sources, duoplasmatrons, field emission sources, and a great many more all have their high current variants. High current ion beams of gaseous and metallic species can be generated in a number of different ways. Ion sources of the kind developed at various laboratories around the world for the production of intense neutral beams for controlled fusion experiments are used to form large area proton deuteron beams of may tens of Amperes, and this technology can be used for other applications also. There has been significant progress in recent years in the use of microwave ion sources for high current ion beam generation, and this method is likely to find wide application in various different field application. Finally, high current beams of metal ions can be produced using metal vapor vacuum arc ion source technology. After a brief consideration of high current ion source design concepts, these three particular methods are reviewed in this paper

  2. High current density ion source

    International Nuclear Information System (INIS)

    King, H.J.

    1977-01-01

    A high-current-density ion source with high total current is achieved by individually directing the beamlets from an electron bombardment ion source through screen and accelerator electrodes. The openings in these screen and accelerator electrodes are oriented and positioned to direct the individual beamlets substantially toward a focus point. 3 figures, 1 table

  3. Development of a high current ion implanter

    International Nuclear Information System (INIS)

    Choi, Byung Ho; Kim, Wan; Jin, Jeong Tae

    1990-01-01

    A high current ion implanter of the energy of 100 Kev and the current of about 100 mA has been developed for using the high dose ion implantation, surface modification of steels and ceramics, and ion beam milling. The characteristics of the beam extraction and transportation are investigated. A duoPIGatron ion source compatible with gas ion extraction of about 100 mA, a single gap acceleration tube which is able to compensate the divergence due to the space charge effect, and a beam transport system with the concept of the space charge neutralization are developed for the high current machine. The performance of the constructed machine shows that nitrogen, argon, helium, hydrogen and oxygen ion beams are successfully extracted and transported at a beam divergence due to space charge effect is negligible in the operation pressure of 2 x 10 -5 torr. (author)

  4. Simple, high current, antimony ion source

    International Nuclear Information System (INIS)

    Sugiura, H.

    1979-01-01

    A simple metal ion source capable of producing a continuous, uncontaminated, high current beam of Sb ions is presented. It produced a total ion current of 200 μA at 1 kV extraction voltage. A discharge occurred in the source at a pressure of 6 x 10 -4 Torr. The ion current extracted from the source increased with the 3/2 power of the extraction voltage. The perveance of the source and ion density in the plasma were 8 x 10 -9 and 1.8 x 10 11 cm -3 , respectively

  5. Versatile high current metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1992-01-01

    A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multicathode, broad-beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred kiloelectronvolts because of the ion charge state multiplicity, and with a beam current of up to several amps peak pulsed and several tens of milliamps time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line of sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. (orig)

  6. High current ion source development at Frankfurt

    Energy Technology Data Exchange (ETDEWEB)

    Volk, K.; Klein, H.; Lakatos, A.; Maaser, A.; Weber, M. [Frankfurt Univ. (Germany). Inst. fuer Angewandte Physik

    1995-11-01

    The development of high current positive and negative ion sources is an essential issue for the next generation of high current linear accelerators. Especially, the design of the European Spallation Source facility (ESS) and the International Fusion Material Irradiation Test Facility (IFMIF) have increased the significance of high brightness hydrogen and deuterium sources. As an example, for the ESS facility, two H{sup -}-sources each delivering a 70 mA H{sup -}-beam in 1.45 ms pulses at a repetition rate of 50 Hz are necessary. A low emittance is another important prerequisite. The source must operate, while meeting the performance requirements, with a constancy and reliability over an acceptable period of time. The present paper summarizes the progress achieved in ion sources development of intense, single charge, positive and negative ion beams. (author) 16 figs., 7 refs.

  7. High current ion source development at Frankfurt

    International Nuclear Information System (INIS)

    Volk, K.; Klein, H.; Lakatos, A.; Maaser, A.; Weber, M.

    1995-01-01

    The development of high current positive and negative ion sources is an essential issue for the next generation of high current linear accelerators. Especially, the design of the European Spallation Source facility (ESS) and the International Fusion Material Irradiation Test Facility (IFMIF) have increased the significance of high brightness hydrogen and deuterium sources. As an example, for the ESS facility, two H - -sources each delivering a 70 mA H - -beam in 1.45 ms pulses at a repetition rate of 50 Hz are necessary. A low emittance is another important prerequisite. The source must operate, while meeting the performance requirements, with a constancy and reliability over an acceptable period of time. The present paper summarizes the progress achieved in ion sources development of intense, single charge, positive and negative ion beams. (author) 16 figs., 7 refs

  8. Surface ionization ion source with high current

    International Nuclear Information System (INIS)

    Fang Jinqing; Lin Zhizhou; Yu Lihua; Zhan Rongan; Huang Guojun; Wu Jianhua

    1986-04-01

    The working principle and structure of a surface ionization ion source with high current is described systematically. Some technological keypoints of the ion source are given in more detail, mainly including: choosing and shaping of the material of the surface ionizer, heating of the ionizer, distributing of working vapour on the ionizer surface, the flow control, the cooling problem at the non-ionization surface and the ion optics, etc. This ion source has been used since 1972 in the electromagnetic isotope separator with 180 deg angle. It is suitable for separating isotopes of alkali metals and rare earth metals. For instance, in the case of separating Rubidium, the maximum ion current of Rbsup(+) extracted from the ion source is about 120 mA, the maximum ion current accepted by the receiver is about 66 mA, the average ion current is more than 25 mA. The results show that our ion source have advantages of high ion current, good characteristics of focusing ion beam, working stability and structure reliability etc. It may be extended to other fields. Finally, some interesting phenomena in the experiment are disccused briefly. Some problems which should be investigated are further pointed out

  9. Pulsed high current ion beam processing equipment

    International Nuclear Information System (INIS)

    Korenev, S.A.; Perry, A.

    1995-01-01

    A pulsed high voltage ion source is considered for use in ion beam processing for the surface modification of materials, and deposition of conducting films on different substrates. The source consists of an Arkad'ev-Marx high voltage generator, a vacuum ion diode based on explosive ion emission, and a vacuum chamber as substrate holder. The ion diode allows conducting films to be deposited from metal or allow sources, with ion beam mixing, onto substrates held at a pre-selected temperature. The main variables can be set in the ranges: voltage 100-700 kV, pulse length 0.3 μs, beam current 1-200 A depending on the ion chosen. The applications of this technology are discussed in semiconductor, superconductor and metallizing applications as well as the direction of future development and cost of these devices for commercial application. 14 refs., 6 figs

  10. High current pelletron for ion implantation

    International Nuclear Information System (INIS)

    Schroeder, J.B.

    1989-01-01

    Since 1984, when the first production MeV ion implanter (an NEC model MV-T30) went on-line, interest in versatile electrostatic accelerator systems for MeV ion implantation has grown. The systems use a negative ion source to inject a tandem megavolt accelerator. In early systems the 0.4 mA of charging current from the two Pelletron charging chains in the accelerator was sufficient for the low intensity of beams from the ion source. This 2-chain system, however, is no longer adequate for the much higher beam intensities from today's improved ion sources. A 4-chain charging system, which delivers 1.3 mA to the high voltage terminal, was developed and is in operation in new models of NEC S Series Pelletron accelerators. This paper describes the latest beam performance of 1 MV and 1.7 MW Pelletron accelerators with this new 4-chain charging system. (orig.)

  11. A high current high frequency ions gun

    International Nuclear Information System (INIS)

    Coutant, J.; Prevot, F.; Vienet, R.

    1959-01-01

    A 10 mA protons gun has been developed for different purposes. The first part of the report studies the plasma production with a RF electromagnetic field. Then the ion extraction process is analysed with particular reference to space charge phenomena. The last part describes a three electrode electrostatic lens which focusses the beam. (author) [fr

  12. High current density ion beam measurement techniques

    International Nuclear Information System (INIS)

    Ko, W.C.; Sawatzky, E.

    1976-01-01

    High ion beam current measurements are difficult due to the presence of the secondary particles and beam neutralization. For long Faraday cages, true current can be obtained only by negative bias on the target and by summing the cage wall and target currents; otherwise, the beam will be greatly distorted. For short Faraday cages, a combination of small magnetic field and the negative target bias results in correct beam current. Either component alone does not give true current

  13. Compact microwave ion source

    International Nuclear Information System (INIS)

    Leung, K.N.; Walther, S.; Owren, H.W.

    1985-05-01

    A small microwave ion source has been fabricated from a quartz tube with one end enclosed by a two grid accelerator. The source is also enclosed by a cavity operated at a frequency of 2.45 GHz. Microwave power as high as 500 W can be coupled to the source plasma. The source has been operated with and without multicusp fields for different gases. In the case of hydrogen, ion current density of 200 mA/cm -2 with atomic ion species concentration as high as 80% has been extracted from the source

  14. Ion beams from high-current PF facilities

    Energy Technology Data Exchange (ETDEWEB)

    Sadowski, M [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1997-12-31

    Pulsed beams of fast deuterons and impurity or admixture ions emitted from high-current PF-type facilities operated in different laboratories are dealt with. A short comparative analysis of time-integrated and time-resolved studies is presented. Particular attention is paid to the microstructure of such ion beams, and to the verification of some theoretical models. (author). 5 figs., 19 refs.

  15. High current vacuum arc ion source for heavy ion fusion

    International Nuclear Information System (INIS)

    Qi, N.; Schein, J.; Gensler, S.; Prasad, R.R.; Krishnan, M.; Brown, I.

    1999-01-01

    Heavy Ion fusion (HIF) is one of the approaches for the controlled thermonuclear power production. A source of heavy ions with charge states 1+ to 2+, in ∼0.5 A current beams with ∼20 micros pulse widths and ∼10 Hz repetition rates are required. Thermionic sources have been the workhorse for the HIF program to date, but suffer from sloe turn-on, heating problems for large areas, are limited to low (contact) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states, in short and long pulse bursts, with low emittance and high beam currents. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications is investigated. An existing ion source at LBNL was modified to produce ∼0.5 A, ∼60 keV Gd (A∼158) ion beams. The experimental effort concentrated on beam noise reduction, pulse-to-pulse reproducibility and achieving low beam emittance at 0.5 A ion current level. Details of the source development will be reported

  16. The emittance of high current heavy ion beams

    International Nuclear Information System (INIS)

    White, N.R.; Devaney, A.S.

    1989-01-01

    Ion implantation is the main application for high current heavy ion beams. Transfer ratio is defined as the ratio of the total ion current leaving the ion source to the current delivered to the endstation. This ratio is monitored and logged and its importance is explained. It is also affected by other factors, such as the isotopic and molecular composition of the total ion beam. The transfer ratio reveals the fraction of ions which are intercepted by parts of the beamline system. The effects of these ions are discussed in two categories: processing purity and reliability. In discussing the emittance of ribbon beams, the two orthogonal planes are usually considered separately. Longitudinal emittance is determined by slot length and by plasma ion temperature. It has already been revealed that the longitudinal divergence of the beams from BF3 is perhaps double that of the beam from arsenic vapour or argon, at the same total perveance from the ion source. This poses the question: why is the ion temperature higher for BF3 than for As or Ar? The transverse emittance is in practical terms dominated by the divergence. It is the most fruitful area for improvement in most real-world systems. There is an intrinsic divergence arising from initial ion energies within the plasma, and there is emittance growth that can occur as a result of aberration in the beam extraction optics. (N.K.)

  17. Polyatomic ions from a high current ion implanter driven by a liquid metal ion source

    Science.gov (United States)

    Pilz, W.; Laufer, P.; Tajmar, M.; Böttger, R.; Bischoff, L.

    2017-12-01

    High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi2+ ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

  18. Broad-beam, high current, metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1990-07-01

    We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we describe the facility and some of the implants that have been carried out using it, including the 'seeding' of silicon wafers prior to CVD with titanium, palladium or tungsten, the formation of buried iridium silicide layers, and actinide (uranium and thorium) doping of III-V compounds. 16 refs., 6 figs

  19. High-current pulsed ion source for metallic ions

    International Nuclear Information System (INIS)

    Gavin, B.; Abbott, S.; MacGill, R.; Sorensen, R.; Staples, J.; Thatcher, R.

    1981-03-01

    A new sputter-ion PIG source and magnet system, optimized for intermediate charge states, q/A of 0.02 to 0.03, is described. This source will be used with the new Wideroe-based injector for the SuperHILAC. Pulsed electrical currents of several emA of heavy metal ions have been produced in a normalized emittance area of .05π cm-mr. The source system is comprised of two electrically separate anode chambers, one in operation and one spare, which can be selected by remote control. The entire source head is small and quickly removable

  20. Heavy-Ion Injector for the High Current Experiment

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Kwan, J. W.; Prost, L.; Seidl, P.

    2001-10-01

    We report on progress in development of the Heavy-Ion Injector at LBNL, which is being prepared for use as an injector for the High Current Experiment (HCX). It is composed of a 10-cm-diameter surface ionization source, an extraction diode, and an electrostatic quadrupole (ESQ) accelerator, with a typical operating current of 0.6 A of potassium ions at 1.8 MeV, and a beam pulse length of 4.5 microsecs. We have improved the Injector equipment and diagnostics, and have characterized the source emission and radial beam profiles at the diode and ESQ regions. We find improved agreement with EGUN predictions, and improved compatibility with the downstream matching section. Plans are to attach the matching section and the initial ESQ transport section of HCX. Results will be presented and compared with EGUN and WARP simulations.

  1. High current transport experiment for heavy ion inertial fusion

    Directory of Open Access Journals (Sweden)

    L. R. Prost

    2005-02-01

    Full Text Available The High Current Experiment at Lawrence Berkeley National Laboratory is part of the U.S. program to explore heavy-ion beam transport at a scale representative of the low-energy end of an induction linac driver for fusion energy production. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density ∼0.2  μC/m over long pulse durations (4  μs in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo, and electron and gas cloud effects. We present the results for a coasting 1 MeV K^{+} ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius for which the transverse phase space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor (≈80% is achieved with acceptable emittance growth and beam loss, even though the initial beam distribution is not ideal (but the emittance is low nor in thermal equilibrium. We achieved good envelope control, and rematching may only be needed every ten lattice periods (at 80% fill factor in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

  2. Some high-current ion sources for materials modification

    International Nuclear Information System (INIS)

    Taylor, T.

    1989-01-01

    Ion sources for materials modification have evolved through three distinct generations. The first generation was adopted from research accelerators. These cold-cathode plasma-discharge devices generate beam currents of less than 100 μA. The hot-cathode plasma-discharge ion sources, originally developed for isotope separation, comprise the second generation. They produce between 100 μA and 10 mA of beam current. The third generation ion sources give beam currents in excess of 10 mA. This technology, transferred from industrial accelerators, has already made SIMOX (Separation by IMplanted OXygen) into a commercially viable semiconductor process and promises to do the same for ion implantation of metals and insulators. The author focuses on the third generation technology that will play a key role in the future of ion implantation. 10 refs.; 5 figs.; 2 tabs

  3. Design considerations for high-current superconducting ion linacs

    International Nuclear Information System (INIS)

    Delayen, J.R.; Bohn, C.L.; Micklich, B.J.; Roche, C.T.; Sagalovsky, L.

    1993-01-01

    Superconducting linacs may be a viable option for high-current applications such as fusion materials irradiation testing, spallation neutron source, transmutation of radioactive waste, tritium production, and energy production. These linacs must run reliably for many years and allow easy routine maintenance. Superconducting cavities operate efficiently with high cw gradients, properties which help to reduce operating and capital costs, respectively. However, cost-effectiveness is not the sole consideration in these applications. For example, beam impingement must be essentially eliminated to prevent unsafe radioactivation of the accelerating structures, and thus large apertures are needed through which to pass the beam. Because of their high efficiency, superconducting cavities can be designed with very large bore apertures, thereby reducing the effect of beam impingement. Key aspects of high-current cw superconducting linac designs are explored in this context

  4. Development of high current low energy H+ ion source

    International Nuclear Information System (INIS)

    Forrester, A.T.; Crow, J.T.; Goebel, D.M.

    1978-01-01

    The ultimate goal of this work is the development of an ion source suitable for double charge exchange of D + ions to D - ions in cesium or other vapor. Since the fraction of the D + which changes to D - may be as high as 0.35 in the energy below one keV, the process appears very favorable. What is desired is a source of several hundred cm 2 area, with a D + current density greater than, say 0.2A/cm 2 . Small angular spread is essential with up to about 0.1 radian being acceptable. A simple approach to this problem appears to be through fine mesh extraction electrodes. In this system a single grid facing the ion source plasma constitutes the entire extraction electrode system. If the potential difference between the grid and the source plasma is large compared to the ion energy at the plasma boundary, then the distance s 0 is just the Child-Langmuir distance corresponding to the ion current density J and the potential difference V 0 between the plasma and the grid

  5. Characteristics of a high current ion source operated with lithium

    International Nuclear Information System (INIS)

    Bay, H.L.; Dullni, E.; Leismann, P.

    1986-05-01

    A low pressure arc ion source has been tested for operation with lithium. Currents up to 120 mA could be extracted through a multiple aperture extraction system at energies of 30 keV. The ion beam was neutralized up to 70% in a charge exchange cell filled with lithium vapour. The beam divergence ranged from 20 to 25 mrad full angle deduced from the spatial distribution of the collision induced Li I resonance line. Current densities from 2 to 3 mA/m 2 at a distance of 1.9 m from the source were measured either by laser induced fluorescence or with a Faraday cup. (orig.)

  6. Beam brilliance investigation of high current ion beams at GSI heavy ion accelerator facility.

    Science.gov (United States)

    Adonin, A A; Hollinger, R

    2014-02-01

    In this work the emittance measurements of high current Ta-beam provided by VARIS (Vacuum Arc Ion Source) ion source are presented. Beam brilliance as a function of beam aperture at various extraction conditions is investigated. Influence of electrostatic ion beam compression in post acceleration gap on the beam quality is discussed. Use of different extraction systems (single aperture, 7 holes, and 13 holes) in order to achieve more peaked beam core is considered. The possible ways to increase the beam brilliance are discussed.

  7. High current pulsed linear ion accelerators for inertial fusion applications

    International Nuclear Information System (INIS)

    Humphries, S. Jr.; Yonas, G.; Poukey, J.W.

    1978-01-01

    Pulsed ion beams have a number of advantages for use as inertial fusion drivers. Among these are classical interaction with targets and good efficiency of production. As has been pointed out by members of the accelerator community, multistage accelerators are attractive in this context because of lower current requirements, low power flow per energy conversion stage and low beam divergence at higher ion energies. On the other hand, current transport limits in conventional accelerators constrain them to the use of heavy ions at energies much higher than those needed to meet the divergence requirements, resulting in large, costly systems. We have studied methods of neutralizing ion beams with electrons within the accelerator volume to achieve higher currents. The aim is to arrive at an inexpensive accelerator that can advantageously use existing pulsed voltage technology while being conservative enough to achieve a high repetition rate. Typical output parameters for reactor applications would be an 0 + beam of 30 kA at 300 MeV. We will describe reactor scaling studies and the physics of neutralized linear accelerators using magnetic fields to control the electron dynamics. Recent results are discussed from PULSELAC, a five stage multikiloampere device being tested at Sandia Laboratories

  8. Microwave proton source development for a high-current linac injector

    International Nuclear Information System (INIS)

    Sherman, J.; Bolme, G.; Geisik, C.

    1995-01-01

    Powerful CW proton linear accelerators (100-mA at 0.5--1.0 GeV) are being proposed for spallation neutron-source applications. A 75-keV, 110-mA dc proton injector using a microwave ion source is being tested for these applications. It has achieved 80-keV, 110-mA hydrogen-ion-beam operation. Video and dc beam-current toroid diagnostics are operational, and an EPICS control system is also operational on the 75-keV injector. A technical base development program has also been carried out on a 50-keV injector obtained from Chalk River Laboratories, and it includes low-energy beam transport studies, ion source lifetime tests, and proton-fraction enhancement studies. Technical base results and the present status of the 75-keV injector will be presented

  9. Characterization and control of wafer charging effects during high-current ion implantation

    International Nuclear Information System (INIS)

    Current, M.I.; Lukaszek, W.; Dixon, W.; Vella, M.C.; Messick, C.; Shideler, J.; Reno, S.

    1994-02-01

    EEPROM-based sense and memory devices provide direct measures of the charge flow and potentials occurring on the surface of wafers during ion beam processing. Sensor design and applications for high current ion implantation are discussed

  10. Architecture and control of a high current ion implanter system

    International Nuclear Information System (INIS)

    Bayer, E.H.; Paul, L.F.; Kranik, J.R.

    1979-01-01

    The design of an ion implant system for use in production requires that special attention be given to areas of design which normally are not emphasized on research or development type ion implanters. Manually operated, local controls are replaced by remote controls, automatic sequencing, and digital displays. For ease of maintenance and replication the individual components are designed as simply as possible and are contained in modules of separate identities, joined only by the beam line and electrical interconnections. A production environment also imposes requirements for the control of contamination and maintainability of clean room integrity. For that reason the major portion of the hardware is separated from the clean operator area and is housed in a maintenance core area. The controls of a production system should also be such that relatively unskilled technicians are able to operate the system with optimum repeatability and minimum operator intervention. An extensive interlock system is required. Most important, for use in production the ion implant system has to have a relatively high rate of throughput. Since the rate of throughput at a given dose is a function of beam current, pumpdown time and wafer handling capacity, design of components affecting these parameters has been optimized. Details of the system are given. (U.K.)

  11. Electrode cooling for long pulse high current ion sources

    International Nuclear Information System (INIS)

    McKenzie-Wilson, R.B.

    1979-01-01

    The need for cooling of electrode surface in ion sources for neutral beam line applications is summarized. The properties of possible cooling fluids are discussed and the decision to use water as a cooling fluid of choice is explained. The influence of source geometry on the design of a cooling canal is examined and two possible designs are presented. The need for model testing and the results of the tests on a model cathode are also discussed. Some remarks are also made on a method of predicting burnout failure of a cooled electrode

  12. High current DC negative ion source for cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Etoh, H., E-mail: Hrh-Etoh@shi.co.jp; Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Sakuraba, J.; Kato, T.; Mitsumoto, T.; Hiasa, T.; Yajima, S. [Sumitomo Heavy Industries, Ltd., Tokyo 141-6025 (Japan); Onai, M.; Hatayama, A. [Graduate School of Science and Technology, Keio University, Kanagawa 223-8522 (Japan); Shibata, T. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Okumura, Y. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Aomori 039-3212 (Japan)

    2016-02-15

    A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H{sup −} beam of 10 mA and D{sup −} beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H{sup −} beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H{sup −} current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H{sup −} production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H{sup −} current dependence on the arc power.

  13. Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications

    International Nuclear Information System (INIS)

    Chacon-Golcher, E.

    2002-01-01

    This dissertation develops diverse research on small (diameter ∼ few mm), high current density (J ∼ several tens of mA/cm 2 ) heavy ion sources. The research has been developed in the context of a programmatic interest within the Heavy Ion Fusion (HIF) Program to explore alternative architectures in the beam injection systems that use the merging of small, bright beams. An ion gun was designed and built for these experiments. Results of average current density yield ( ) at different operating conditions are presented for K + and Cs + contact ionization sources and potassium aluminum silicate sources. Maximum values for a K + beam of ∼90 mA/cm 2 were observed in 2.3 (micro)s pulses. Measurements of beam intensity profiles and emittances are included. Measurements of neutral particle desorption are presented at different operating conditions which lead to a better understanding of the underlying atomic diffusion processes that determine the lifetime of the emitter. Estimates of diffusion times consistent with measurements are presented, as well as estimates of maximum repetition rates achievable. Diverse studies performed on the composition and preparation of alkali aluminosilicate ion sources are also presented. In addition, this work includes preliminary work carried out exploring the viability of an argon plasma ion source and a bismuth metal vapor vacuum arc (MEVVA) ion source. For the former ion source, fast rise-times (∼ 1 (micro)s), high current densities (∼ 100 mA/cm 2 ) and low operating pressures ( e psilon) n (le) 0.006 π mm · mrad) although measured currents differed from the desired ones (I ∼ 5mA) by about a factor of 10

  14. Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chacon-Golcher, Edwin [Univ. of California, Berkeley, CA (United States)

    2002-06-01

    This dissertation develops diverse research on small (diameter ~ few mm), high current density (J ~ several tens of mA/cm2) heavy ion sources. The research has been developed in the context of a programmatic interest within the Heavy Ion Fusion (HIF) Program to explore alternative architectures in the beam injection systems that use the merging of small, bright beams. An ion gun was designed and built for these experiments. Results of average current density yield () at different operating conditions are presented for K+ and Cs+ contact ionization sources and potassium aluminum silicate sources. Maximum values for a K+ beam of ~90 mA/cm2 were observed in 2.3 μs pulses. Measurements of beam intensity profiles and emittances are included. Measurements of neutral particle desorption are presented at different operating conditions which lead to a better understanding of the underlying atomic diffusion processes that determine the lifetime of the emitter. Estimates of diffusion times consistent with measurements are presented, as well as estimates of maximum repetition rates achievable. Diverse studies performed on the composition and preparation of alkali aluminosilicate ion sources are also presented. In addition, this work includes preliminary work carried out exploring the viability of an argon plasma ion source and a bismuth metal vapor vacuum arc (MEVVA) ion source. For the former ion source, fast rise-times (~ 1 μs), high current densities (~ 100 mA/cm+) and low operating pressures (< 2 mtorr) were verified. For the latter, high but acceptable levels of beam emittance were measured (εn ≤ 0.006 π· mm · mrad) although measured currents differed from the desired ones (I ~ 5mA) by about a factor of 10.

  15. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1996-01-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several μs) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  16. High ion charge states in a high-current, short-pulse, vacuum arc ion source

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1995-09-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1--4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several micros) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  17. Experimental study of a high-current FEM with a broadband microwave system

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, G.G.; Bratman, V.L.; Ginzburg, N.S. [Institute of Applied Physics, Nizhny Novgorod (Russian Federation)] [and others

    1995-12-31

    One of the main features of FELs and FEMs is the possibility of fast and wideband tuning of the resonant frequency of active media, which can be provided by changing the particle energy. For a frequency adjustable FEM-oscillator, a broadband microwave system, which is simply combined with an electron-optical FEM system and consists of an oversized waveguide and reflectors based on the microwave beams multiplication effect has been proposed and studied successfully in {open_quotes}cold{close_quotes} measurements. Here, the operating ability of a cavity, that includes some key elements of the broadband microwave system, was tested in the presence of an electron beam. To provide large particle oscillation velocities in a moderate undulator field and the presence of a guide magnetic field, the FEM operating regime of double resonance was chosen. In this regime the cyclotron as well as undulator resonance conditions were satisfied. The FEM-oscillator was investigated experimentally on a high-current accelerator {open_quotes}Sinus-6{close_quotes} that forms an electron beam with particle energy 500keV and pulse duration 25ns. The aperture with a diameter 2.5mm at the center of the anode allows to pass through only the central fraction of the electron beam with a current about 100A and a small spread of longitudinal velocities of the particles. Operating transverse velocity was pumped into the electron beam in the pulse plane undulator of a 2.4cm period. The cavity with a frequency near 45GHz consists of a square waveguide and two reflectors. The broadband up-stream reflector based on the multiplication effect had the power reflectivity coefficient more than 90% in the frequency band 10% for the H{sup 10} wave of the square waveguide with the maximum about 100% at a frequency 45GHz. The down-stream narrow-band Bragg reflector had the power reflection coefficient approximately 80% in the frequency band of 4% near 45GHz for the operating mode.

  18. Interaction of high-current relativistic electron beams with plasma. Physical nature of the phenomenon and its application in microwave electronics

    International Nuclear Information System (INIS)

    Rukhadze, A.A.

    1981-01-01

    Pulsed high-current electron beams with characteristic parameters: electron energy 10 5 -10 7 eV, electron current 10 3 -10 6 A, pulse duration 10 -8 -10 -6 s, beam energy 10 2 -10 6 J and power 10 8 -10 13 W, are widely used in different branches of science and technology such as controlled thermonuclear fusion, relativistic microwave electronics, powerful semiconductors, chemical and gaseous lasers, new principles of heavy-ion acceleration, and long-distance energy transmission. The paper discusses a new branch of science - pulsed high-current electronics, which has its own experimental technique and methods of theoretical analysis. Parts I and II determine what is meant by ''high current'' in an electron beam and calculate the maximum obtainable current values; these calculations are made for the simplest geometrical configurations realizable in practice. Current methods for theoretical analysis of high-current electron beam physics are described, together with classification of current experimental devices for generating such beams according to high-current parameters. The stability of electron beams is discussed and the concept of critical currents is introduced. Part III gives a detailed account of plasma-beam instability which occurs on the interaction of a high-current electron beam with high-density space-limited plasma. The linear and non-linear stages of beam instability are considered. The given theory is used for calculations for amplifiers and microwave generators of electromagnetic radiation. Finally, the experimental achievements in high-current relativistic microwave electronics are reviewed. (author)

  19. High current pulsed ion inductor accelerator for destruction of radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S.A.; Puzynin, I.V.; Samoilov, V.N.; Sissakian, A.N. [Joint Inst. for Nuclear Research, Dubna (Russian Federation)

    1997-09-01

    The project of a high current pulsed linear ion accelerator is described in this paper. The accelerator consists of an ion injector, a system of charge and energy separation, an inductor accelerator and an output system. The ion source with explosive ion emission can produce all kinds of ions. The separation system includes a pulsed magnetic system. The inductors are based on amorphous iron with inside magnetic elements. 3 refs., 3 figs.

  20. High current pulsed ion inductor accelerator for destruction of radioactive wastes

    International Nuclear Information System (INIS)

    Korenev, S.A.; Puzynin, I.V.; Samoilov, V.N.; Sissakian, A.N.

    1997-01-01

    The project of a high current pulsed linear ion accelerator is described in this paper. The accelerator consists of an ion injector, a system of charge and energy separation, an inductor accelerator and an output system. The ion source with explosive ion emission can produce all kinds of ions. The separation system includes a pulsed magnetic system. The inductors are based on amorphous iron with inside magnetic elements. 3 refs., 3 figs

  1. Transport and acceleration of the high-current ion beam in magneto-isolated gap

    International Nuclear Information System (INIS)

    Karas', V.I.; Kornilov, E.A.; Manuilenko, O.V.; Fedorovskaya, O.V.; Tarakanov, V.P.

    2015-01-01

    The possibility of transportation and acceleration of the high-current ion beam in the magneto-isolated gap has been demonstrated. Found the parameters of the system and beams (the magnetic field produced by the coils with opposing currents, the size of the system, and the parameters of the beams), under which the uniform acceleration of the high-current ion beam all along the gap length is realized. It is shown that the quality of the ion beam, during transport and acceleration, at the exit of the gap is acceptable for many technological applications.

  2. High-current heavy-ion accelerator system and its application to material modification

    International Nuclear Information System (INIS)

    Kishimoto, Naoki; Takeda, Yoshihiko; Lee, C.G.; Umeda, Naoki; Okubo, Nariaki; Iwamoto, Eiji

    2001-01-01

    A high-current heavy-ion accelerator system has been developed to realize intense particle fluxes for material modification. The facility of a tandem accelerator attained 1 mA-class ion current both for negative low-energy ions and positive high-energy ions. The negative ion source of the key device is of the plasma-sputter type, equipped with mutli-cusp magnets and Cs supply. The intense negative ions are either directly used for material irradiation at 60 keV or further accelerated up to 6 MeV after charge transformation. Application of negative ions, which alleviates surface charging, enables us to conduct low-energy high-current irradiation on insulating substrates. Since positive ions above the MeV range are irrelevant for Coulomb repulsion, the facility as a whole meets the needs of high-current irradiation onto insulators over a wide energy range. Application of high flux ions provides technological merits not only for efficient implantation but also for essentially different material kinetics, which may become an important tool of material modification. Other advantages of the system are co-irradiation by intense laser and in-situ detection of kinetic processes. For examples of material modifications, we present nanoparticle fabrication in insulators, and synergistic phenomena by co-irradiation due to ions and photons. (author)

  3. Simulation of electron and ion bipolar flow in high current diode with magnetic insulation

    International Nuclear Information System (INIS)

    Vrba, P.; Engelko, V.I.

    1990-08-01

    Numerical simulation of the formation of the collector ion flow in a magnetically insulated ion diode (MID) with a hollow cylindrical and cone-shaped cathode was studied. Such cathodes are often used for the production of tubular high current microsecond electron beams. The ions, emitted by the collector and born as a result of ionization of the residual gas by the electron beam, are focused into the cathode plasma region. This effect can adversely influence the diode operation

  4. High current pulsed ion inductor accelerator for destruction of radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S A; Puzynin, I V; Samojlov, V N; Sissakyan, A N [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    1997-12-31

    A new high-current pulsed linear induction accelerator proposed for application in beam-driven transmutation technologies is described. The accelerator consists of an ion injector, of ion separation and induction accelerating systems, and of an output system for extracting an ion beam into open air. An ion source with explosive ion emission, capable of producing various kinds of ions, is used as an injector. The ion separator exploits a pulsed magnetic system. The induction acceleration structure includes inductors with amorphous iron cores. Imbedded magnetic elements assure the ion beam transport. Main parameters of the accelerator are given in the paper and the design of an ion injector is discussed in more detail. (J.U.). 3 figs., 3 refs.

  5. High current pulsed ion inductor accelerator for destruction of radioactive wastes

    International Nuclear Information System (INIS)

    Korenev, S.A.; Puzynin, I.V.; Samojlov, V.N.; Sissakyan, A.N.

    1996-01-01

    A new high-current pulsed linear induction accelerator proposed for application in beam-driven transmutation technologies is described. The accelerator consists of an ion injector, of ion separation and induction accelerating systems, and of an output system for extracting an ion beam into open air. An ion source with explosive ion emission, capable of producing various kinds of ions, is used as an injector. The ion separator exploits a pulsed magnetic system. The induction acceleration structure includes inductors with amorphous iron cores. Imbedded magnetic elements assure the ion beam transport. Main parameters of the accelerator are given in the paper and the design of an ion injector is discussed in more detail. (J.U.). 3 figs., 3 refs

  6. Recent results with a high-current, heavy-ion source system

    International Nuclear Information System (INIS)

    Keller, R.; Spaedtke, P.; Emig, H.

    1986-01-01

    In the last conference of this series, an improved high-current ion source for gases, CORDIS was presented. This source has been further developed to allow the processing of substances which are not volatile at room temperature. One of these modifications, HORDIS, incorporates an oven whereas the third version works at rather moderate temperatures and can be fed through a slightly heated external bottle. With this source system, high-current ion beams in the 100 mA range can be produced for a considerable part of the periodic table. Operation parameters and experiences with the sources are discussed, and the most recent results for all versions are given. (author)

  7. Characteristics of a High Current Helicon Ion Source With High Monatomic Fraction

    International Nuclear Information System (INIS)

    Jung, Hwa-Dong; Chung, Kyoung-Jae; Hwang, Yong-Seok

    2006-01-01

    Applications of neutron need compact and high yield neutron sources as well as very intense neutron sources from giant devices such as accelerators. Ion source based neutron sources using nuclear fusion reactions such as D(d, 3He)n, D(t, 4He)n can meet the requirements. This type of neutron generators can be simply composed of an ion source and a target. High-performance neutron generators with high yield require ion sources with high beam current, high monatomic fraction and long lifetime. Helicon ion source can meet these requirements. To make high current ion source, characteristics of helicon plasma such as high plasma density can be utilized. Moreover, efficient plasma heating with RF power lead high fraction of monatomic ion beam. Here, Characteristics of helicon plasma sources are described. Design and its performances of a helicon ion source are presented

  8. Ion production and bipolar fluxes in a high-current plasma-filled diode

    International Nuclear Information System (INIS)

    Ivanenkov, G.V.

    1982-01-01

    The model and the evolution of behaviour of binary layers (BL) in expanding plasma of high current plasma-filled diode are described. The model estimates ion current and the laws of plasma expansion at the stage of BL intensive growth. The density range (10 12 -10 15 cm -3 ) is determined in which diode impedance growth takes place in connection with BL appearance. The density of ion current at the outlet of diode is 10 A/cm 2

  9. Computer programmes for high current ion trajectories in a magnetic sector-type mass separator

    International Nuclear Information System (INIS)

    Nakai, Akira

    1988-01-01

    According to theoretical calculations previously proposed by the author, a new programme 'MALT' for electronic computers has been developed for numerical calculations of ion trajectories of a high current ion beam traversing a magnetic sector-type mass separator. In the programme, both effects of the fringing field and the space charge are taken into account in an analytical way, so that numerical calculations can be done straightforwardly. Furthermore, it becomes also possible to analyze and cotrol the trajectories of the high current ion beam. The programme MALT contains several subroutine programmes which are separated individually for the convenience of various calculations with respect to the high current ion beam. To demonstrate the calculations by the use of these subroutine programmes, a main programme for the calculation of the trajectories in the whole region of the separator is shown, which also makes it possible to draw the traces of the trajectories. The trajectories calculated by the proposed programme have been compared with the images of the ion beams recorded on novel dry plates developed by the author: the comparison enables us to evaluate the effective space charge and the effective space charge potential, and to analyze the behaviour of the beam of neutral particles accompanying the ion beam. (author)

  10. Development of the High Current Ion Source for Neutral Beam Injection

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hun Ju; Kim, S. H.; Jang, D. H. [Jae Ju University, Jaeju (Korea, Republic of)

    1997-08-01

    The scope of the 1st year research is to design an 140keV deuterium ion source which has a beam current of 30-40A. According to the collected data, the model of an ion source for NBI of KSTAR was established. The negative ion source, which has good neutralization effecting in high energy, was selected. To generate a plasma, the thoriated tungsten filament was adopted. To increase the efficiency of plasma, the multi cusp type magnetic field was attached. The magnetic field was calculated by POISSON code. The extraction structure was designed with EGUN code, to extract the high quality ion beam. The design of a high current ion source for NBI was carried out. To develop the high current ion source with the high operational stability and the long lifetime, the parameters including an arc current, gas pressure and extraction voltage should be optimized. If designed ion source would be fabricated, its parameters could be optimized experimentally. Through the optimization of the ion source parameter, the core technology for NBI is established and the experiment of current drive in the fusion device can be performed. This technology also can be applied to the synthesis of new material and semiconductor industry. 18 refs., 11 tabs., 19 figs. (author)

  11. High-current negative hydrogen ion beam production in a cesium-injected multicusp source

    International Nuclear Information System (INIS)

    Takeiri, Y.; Tsumori, K.; Kaneko, O.

    1997-01-01

    A high-current negative hydrogen ion source has been developed, where 16.2 A of the H - current was obtained with a current density of 31 mA/cm 2 . The ion source is a multicusp source with a magnetic filter for negative ion production, and cesium vapor is injected into the arc chamber, leading to enhancement of the negative ion yields. The cesium-injection effects are discussed, based on the experimental observations. Although the surface production of the negative ions on the cesium-covered plasma grid is thought to be a dominant mechanism of the H - current enhancement, the cesium effects in the plasma volume, such as the cesium ionization and the electron cooling, are observed, and could contribute to the improved operation of the negative ion source. (author)

  12. Application of radiofrequency superconductivity to accelerators for high-current ion beams

    International Nuclear Information System (INIS)

    Delayen, J.R.; Bohn, C.L.; Kennedy, W.L.; Roche, C.T.; Sagalovsky, L.

    1992-01-01

    A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high-current, high-brightness ion beam. During the last few years, considerable progress has been made both experimentally and theoretically toward this application. Recent tests of niobium resonators for ion acceleration have yielded average accelerating gradients as high as 18 MV/m. In an experiment with a radio-frequency quadrupole geometry, niobium was found to sustain cw peak surface electric fields as high as 128 MV/m over large (10 cm) surface areas. Theoretical studies of beam halo, cumulative beam breakup and alternating-phase focusing have also yielded important results. This paper su-summarizes the recent progress and identifies current and future work in the areas of superconducting accelerator technology for high-current ion beams

  13. Detection and clearing of trapped ions in the high current Cornell photoinjector

    Directory of Open Access Journals (Sweden)

    S. Full

    2016-03-01

    Full Text Available We have recently performed experiments to test the effectiveness of three ion-clearing strategies in the Cornell high intensity photoinjector: DC clearing electrodes, bunch gaps, and beam shaking. The photoinjector reaches a new regime of linac beam parameters where high continuous wave beam currents lead to ion trapping. Therefore ion mitigation strategies must be evaluated for this machine and other similar future high current linacs. We have developed several techniques to directly measure the residual trapped ions. Our two primary indicators of successful clearing are the amount of ion current removed by a DC clearing electrode, and the absence of bremsstrahlung radiation generated by beam-ion interactions. Measurements were taken for an electron beam with an energy of 5 MeV and continuous wave beam currents in the range of 1–20 mA. Several theoretical models have been developed to explain our data. Using them, we are able to estimate the clearing electrode voltage required for maximum ion clearing, the creation and clearing rates of the ions while employing bunch gaps, and the sinusoidal shaking frequency necessary for clearing via beam shaking. In all cases, we achieve a maximum ion clearing of at least 70% or higher, and in some cases our data is consistent with full ion clearing.

  14. Inverted end-Hall-type low-energy high-current gaseous ion source

    International Nuclear Information System (INIS)

    Oks, E. M.; Vizir, A. V.; Shandrikov, M. V.; Yushkov, G. Yu.; Grishin, D. M.; Anders, A.; Baldwin, D. A.

    2008-01-01

    A novel approach to low-energy, high-current, gaseous ion beam generation was explored and an ion source based on this technique has been developed. The source utilizes a dc high-current (up to 20 A) gaseous discharge with electron injection into the region of ion generation. Compared to the conventional end-Hall ion source, the locations of the discharge anode and cathode are inverted: the cathode is placed inside the source and the anode outside, and correspondingly, the discharge current is in the opposite direction. The discharge operates in a diverging axial magnetic field, similar to the end-Hall source. Electron generation and injection is accomplished by using an additional arc discharge with a ''cold'' (filamentless) hollow cathode. Low plasma contamination is achieved by using a low discharge voltage (avoidance of sputtering), as well as by a special geometric configuration of the emitter discharge electrodes, thereby filtering (removing) the erosion products stemming from the emitter cathode. The device produces a dc ion flow with energy below 20 eV and current up to 2.5 A onto a collector of 500 cm 2 at 25 cm from the source edge, at a pressure ≥0.02 Pa and gas flow rate ≥14 SCCM. The ion energy spread is 2 to 3 eV (rms). The source is characterized by high reliability, low maintenance, and long lifetime. The beam contains less than 0.1% of metallic ions. The specific electric energy consumption is 400 eV per ion registered at the collector. The source operates with noble gases, nitrogen, oxygen, and hydrocarbons. Utilizing biasing, it can be used for plasma sputtering, etching, and other ion technologies

  15. Microfabricated Microwave-Integrated Surface Ion Trap

    Science.gov (United States)

    Revelle, Melissa C.; Blain, Matthew G.; Haltli, Raymond A.; Hollowell, Andrew E.; Nordquist, Christopher D.; Maunz, Peter

    2017-04-01

    Quantum information processing holds the key to solving computational problems that are intractable with classical computers. Trapped ions are a physical realization of a quantum information system in which qubits are encoded in hyperfine energy states. Coupling the qubit states to ion motion, as needed for two-qubit gates, is typically accomplished using Raman laser beams. Alternatively, this coupling can be achieved with strong microwave gradient fields. While microwave radiation is easier to control than a laser, it is challenging to precisely engineer the radiated microwave field. Taking advantage of Sandia's microfabrication techniques, we created a surface ion trap with integrated microwave electrodes with sub-wavelength dimensions. This multi-layered device permits co-location of the microwave antennae and the ion trap electrodes to create localized microwave gradient fields and necessary trapping fields. Here, we characterize the trap design and present simulated microwave performance with progress towards experimental results. This research was funded, in part, by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA).

  16. Aberrations due to solenoid focusing of a multiply charged high-current ion beam

    CERN Document Server

    Grégoire, G; Lisi, N; Schnuriger, J C; Scrivens, R; Tambini, J

    2000-01-01

    At the output of a laser ion source, a high current of highly charged ions with a large range of charge states is available. The focusing of such a beam by magnetic elements causes a nonlinear space-charge field to develop which can induce large aberrations and emittance growth in the beam. Simulation of the beam from the CERN laser ion source will be presented for an ideal magnetic and electrostatic system using a radially symmetric model. In addition, the three dimensional software KOBRA3 is used for the simulation of the solenoid line. The results of these simulations will be compared with experiments performed on the CERN laser ion source with solenoids (resulting in a hollow beam) and a series of gridded electrostatic lenses. (5 refs).

  17. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    International Nuclear Information System (INIS)

    Haseroth, Helmut; Hora, Heinrich; Regensburg Inst. of Tech.

    1996-01-01

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10 11 C 4+ ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ''hot'' electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author)

  18. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  19. A high current metal vapour vacuum arc ion source for ion implantation studies

    International Nuclear Information System (INIS)

    Evans, P.J.; Noorman, J.T.; Watt, G.C.; Cohen, D.D.; Bailey, G.M.

    1989-01-01

    The main features of the metal vapour vacuum arc(MEVA) as an ion source are presented. The technology utilizes the plasma production capabilities of a vacuum arc cathode. Some of the ions produced in this discharge flow through the anode and the 3 extraction grids to form an extracted ion beam. The high beam current and the potential for generating broad beams, make this technology suitable for implantation of large surface areas. The composition of the vacuum arc cathode determines the particular ions obtained from the MEVA source. 3 refs., 1 tab., 2 figs

  20. Recent advances in high current vacuum arc ion sources for heavy ion fusion

    CERN Document Server

    Qi Nian Sheng; Prasad, R R; Krishnan, M S; Anders, A; Kwan, J; Brown, I

    2001-01-01

    For a heavy ion fusion induction linac driver, a source of heavy ions with charge states 1+-3+, approx 0.5 A current beams, approx 20 mu s pulse widths and approx 10 Hz repetition rates is required. Thermionic sources have been the workhorse for the Heavy Ion Fusion (HIF) program to date, but suffer from heating problems for large areas and contamination. They are limited to low (contact) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states in short and long pulse bursts and high beam current density. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications was investigated. We have modifie...

  1. Collective acceleration of electrons and ions in a high current relativistic electron beam. Final report

    International Nuclear Information System (INIS)

    Nation, J.A.

    1992-01-01

    This report describes work carried out on DOE contract number DE-AC02-80ER10569 during the period December 15, 1979 to May 31, 1992. The original purpose of this research was to investigate the use of slow space charge waves on weakly relativistic electron beams for ion acceleration. The work had three major objectives: development of a suitable ion injector, growth and study of the properties of slow space charge waves on an electron beam, and a combination of the two components into a suitable proof-of-principle demonstration of the wave accelerator. Work focused on the first two of these objectives. Control of the space charge waves' phase velocity was not obtained to the degree required for a working accelerator, so the project was duly terminated in favor of a program which focused on generating ultra high power microwave signals suitable for use in the next linear collider. Work done to develop suitable efficient, inexpensive, phase-stable microwave sources, with peak powers of up to 1 GW in the X band in pulses shorter than 1 ns, is described. Included are lists of the journal and conference papers resulting from this work, as well as a list of graduate students who completed their Ph.D. studies on the projects described in this report

  2. Development of an IH-type linac for the acceleration of high current heavy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Haehnel, Jan Hendrik

    2017-07-20

    The Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt will provide unprecedented intensities of protons and heavy ions up to uranium at energies of up to 29 GeV for protons and 2.7 GeV/u for U{sup 28+}. To achieve high intensities in the synchrotron accelerators, high beam currents have to be provided by the injector linear accelerators. High current heavy ion beams are provided by the Universal Linear Accelerator (UNILAC), which in its current state will not be able to provide the required FAIR beam currents. This thesis deals with the development of upgrades for the UNILAC to ensure its high current capability. The first improvement is a matching section (MEBT) for the interface between the RFQ and the IH-DTL of the existing high current injector HSI at the UNILAC. With this new MEBT section, particle losses are eliminated and the overall beam quality is improved. As a second improvement, a complete replacement of the existing Alvarez-DTL is presented. A combination of efficient IH-type cavities and KONUS beam dynamics results in a reduction of the linac length from about 60 m (Alvarez) to just 23 m (new IH-DTL) while providing the same energy and fulfilling FAIR requirements of a high beam current and beam quality. This thesis contains a detailed beam dynamics design of the new linac including some fundamental investigations of the KONUS beam dynamics concept. A cross-check of the beam dynamics design was performed with two independent multi-particle simulation codes. Detailed error studies were conducted to investigate the influence of manufacturing, alignment and operating errors on the beam dynamics performance. Additionally, all five linac cavities were designed, optimized, and their RF parameters including power requirements calculated to provide a comprehensive linac design.

  3. Development of an IH-type linac for the acceleration of high current heavy ion beams

    International Nuclear Information System (INIS)

    Haehnel, Jan Hendrik

    2017-01-01

    The Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt will provide unprecedented intensities of protons and heavy ions up to uranium at energies of up to 29 GeV for protons and 2.7 GeV/u for U 28+ . To achieve high intensities in the synchrotron accelerators, high beam currents have to be provided by the injector linear accelerators. High current heavy ion beams are provided by the Universal Linear Accelerator (UNILAC), which in its current state will not be able to provide the required FAIR beam currents. This thesis deals with the development of upgrades for the UNILAC to ensure its high current capability. The first improvement is a matching section (MEBT) for the interface between the RFQ and the IH-DTL of the existing high current injector HSI at the UNILAC. With this new MEBT section, particle losses are eliminated and the overall beam quality is improved. As a second improvement, a complete replacement of the existing Alvarez-DTL is presented. A combination of efficient IH-type cavities and KONUS beam dynamics results in a reduction of the linac length from about 60 m (Alvarez) to just 23 m (new IH-DTL) while providing the same energy and fulfilling FAIR requirements of a high beam current and beam quality. This thesis contains a detailed beam dynamics design of the new linac including some fundamental investigations of the KONUS beam dynamics concept. A cross-check of the beam dynamics design was performed with two independent multi-particle simulation codes. Detailed error studies were conducted to investigate the influence of manufacturing, alignment and operating errors on the beam dynamics performance. Additionally, all five linac cavities were designed, optimized, and their RF parameters including power requirements calculated to provide a comprehensive linac design.

  4. Prototype high current, high duty factor negative hydrogen ion source for LAMPF

    International Nuclear Information System (INIS)

    Lawrence, G.P.; Hayward, T.D.; Jackson, J.A.

    1975-01-01

    Present plans for the high current proton storage ring at LAMPF incorporate charge changing (stripping) injection of H - ions in all modes of operation. Achievable stored current levels in this device will be strongly dependent on the maximum H - beam intensity which can be accelerated by the linac, consistent with acceptable beam spill. This requirement has stimulated a program to develop an H - ion source capable of providing a suitably high peak current (up to 25 mA) at high duty factor (up to 12 percent), with a normalized x,x' or y,y' emittance acceptable to the accelerating system. There are presently two main approaches which could lead to H - ion sources providing this kind of performance. These are (a) the charge exchange method, in which an intense proton beam is fractionally converted to H - beam in a suitable charge adding medium, and (b) the direct extraction method, in which H - ions are obtained by a surface emission process associated with a gas discharge plasma. While both approaches may eventually find optimum application in different situations, it is not obvious, at present, which scheme will turn out to be the most satisfactory for LAMPF. A prototype charge exchange H - ion source has been constructed as a first step in the development program and is presently being evaluated. Work on surface emission direct extraction techniques is in the planning stages. (U.S.)

  5. Characterisation Of The Beam Plasma In High Current, Low Energy Ion Beams For Implanters

    International Nuclear Information System (INIS)

    Fiala, J.; Armour, D. G.; Berg, J. A. van der; Holmes, A. J. T.; Goldberg, R. D.; Collart, E. H. J.

    2006-01-01

    The effective transport of high current, positive ion beams at low energies in ion implanters requires the a high level of space charge compensation. The self-induced or forced introduction of electrons is known to result in the creation of a so-called beam plasma through which the beam propagates. Despite the ability of beams at energies above about 3-5 keV to create their own neutralising plasmas and the development of highly effective, plasma based neutralising systems for low energy beams, very little is known about the nature of beam plasmas and how their characteristics and capabilities depend on beam current, beam energy and beamline pressure. These issues have been addressed in a detailed scanning Langmuir probe study of the plasmas created in beams passing through the post-analysis section of a commercial, high current ion implanter. Combined with Faraday cup measurements of the rate of loss of beam current in the same region due to charge exchange and scattering collisions, the probe data have provided a valuable insight into the nature of the slow ion and electron production and loss processes. Two distinct electron energy distribution functions are observed with electron temperatures ≥ 25 V and around 1 eV. The fast electrons observed must be produced in their energetic state. By studying the properties of the beam plasma as a function of the beam and beamline parameters, information on the ways in which the plasma and the beam interact to reduce beam blow-up and retain a stable plasma has been obtained

  6. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    Science.gov (United States)

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800 mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10) s(-1) cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9) s(-1) cm(-2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300 mA, 45 kV deuteron beam directed to D2O target demonstrated 10(9) s(-1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. High-current negative-ion sources for pulsed spallation neutron sources: LBNL workshop, October 1994

    International Nuclear Information System (INIS)

    Alonso, J.R.

    1995-09-01

    The neutron scattering community has endorsed the need for a high-power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 kW source in the UK), and call for a high-current (approx. 100 mA peak) H- source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The I to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. The Workshop reported on here, held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H- source technologies, and identified necessary R ampersand D efforts to bridge the gap

  8. Status of the high current permanent magnet 2.45 GHz ECR ion source at Peking University

    International Nuclear Information System (INIS)

    Peng, S.X.; Song, Z.Z.; Yu, J.X.; Ren, H.T.; Zhang, M.; Yuan, Z.X.; Lu, P.N.; Zhao, J.; Chen, J.E.; Guo, Z.Y.; Lu, Y.R.

    2012-01-01

    Several compact 2.45 GHz Electron Cyclotron Resonance Ion Sources (ECRIS) have been developed at Peking University for ion implantation, for the Separated Function Radio Frequency Quadrupole project (SFRFQ) and for the Peking University Neutron Imaging Facility project (PKUNIFTY). Studies on 2.45 GHz ECR ion sources are concentrated on methods of microwave coupling and microwave window design, magnetic field generation and configuration, as well as the extraction electrodes structure. Investigation also covers the influence of the size of plasma chamber on the discharge efficiency and species factor. Up to now, our sources have produced 25 mA of O + ions, 40 mA of He + ions, 10 mA of N + ions, 100 mA of H + ions and 83 mA of D + ions, respectively. The paper is followed by the slides of the presentation. (authors)

  9. Design of an end station for a high current ion implantation system

    International Nuclear Information System (INIS)

    Kranik, J.R.

    1979-01-01

    During the last 4 to 5 years IBM has been involved in an effort to develop a high current Ion Implantation system with pre-deposition capabilities. The system is dedicated to Arsenic implants, involving doses > 1 x 10 15 ions/cm 2 in the energy range of 30 to 60 keV. A major portion of this effort involved the design of an associated end station capable of producing high uniformity implants with beam currents in the 0.5 to 6.0 mA range. The end station contains all components from the exit of the analyzing magnet, including the exit beamline, process chamber, scan system, wafer handling system, high vacuum pumping package, beam optics, dosimetry system, and associated electronic controls. The unit was restricted to a six wafer (82 mm) batch size to maintain process line compatibility. In addition, implant dose non-uniformity objectives were established at +- 3% (2σ) within a wafer and +- 2% (2σ) wafer-to-wafer. Also, the system was to be capable of implanting 24 wafers/hour at a dose of 7.5 x 10 15 ions/cm 2 . Major consideration in the design was afforded to high reliability, ease of maintenance and production level throughput capabilities. The rationale and evolution of the final end station design is described. (author)

  10. Optimal conditions for high current proton irradiations at the university of Wisconsin's ion beam laboratory

    International Nuclear Information System (INIS)

    Wetteland, C. J.; Field, K. G.; Gerczak, T. J.; Eiden, T. J.; Maier, B. R.; Albakri, O.; Sridharan, K.; Allen, T. R.

    2013-01-01

    The National Electrostatics Corporation's (NEC) Toroidal Volume Ion Source (TORVIS) source is known for exceptionally high proton currents with minimal service downtime as compared to traditional sputter sources. It has been possible to obtain over 150μA of proton current from the source, with over 70μA on the target stage. However, beam fluxes above ∼1×10 17 /m2-s may have many undesirable effects, especially for insulators. This may include high temperature gradients at the surface, sputtering, surface discharge, cracking or even disintegration of the sample. A series of experiments were conducted to examine the role of high current fluxes in a suite of ceramics and insulating materials. Results will show the optimal proton irradiation conditions and target mounting strategies needed to minimize unwanted macro-scale damage, while developing a procedure for conducting preliminary radiation experiments.

  11. On 2D electron cloud dynamics in high-current plasma lens for ion beam focusing

    International Nuclear Information System (INIS)

    Goncharov, A. A.; Litovko, I. V.; Onishchenko, I. N.; Zadorozhny, V. F.

    1997-01-01

    In this paper we are dealing with the appear the stable existence and dynamics of 2-D electron vortical structures in crossed electric and magnetic fields. The collective interactions in which the electron motion is nonlinear and ion motion is linear, is concerned. By using of the kinetic equation and the catastrophe theory approach we deduce an origin of the vortical structures. The nonlinear differential equation for the electric potential in a hydrodynamical approximation is obtained. It describes a drift motion of the electrons in oscillating electric fields of the high-current plasma lens(PL), arising due to presence the principal unremoval radical gradient of the axical component of the magnetic field. It was shown that the considered equations have contained the solutions in the form of the single vortical structures. The stability of the structures are given

  12. Analysis techniques of charging damage studied on three different high-current ion implanters

    Science.gov (United States)

    Felch, S. B.; Larson, L. A.; Current, M. I.; Lindsey, D. W.

    1989-02-01

    One of the Greater Silicon Valley Implant Users' Group's recent activities has been to sponsor a round-robin on charging damage, where identical wafers were implanted on three different state-of-the-art, high-current ion implanters. The devices studied were thin-dielectric (250 Å SiO2), polysilicon-gate MOS capacitors isolated by thick field oxide. The three implanters involved were the Varian/Extrion 160XP, the Eaton/Nova 10-80, and the Applied Materials PI9000. Each implanter vendor was given 48 wafers to implant with 100 keV As+ ions at a dose of 1 × 1016 cm-2. Parameters that were varied include the beam current, electron flood gun current, and chamber pressure. The charge-to-breakdown, breakdown voltage, and leakage current of several devices before anneal have been measured. The results from these tests were inconclusive as to the physical mechanism of charging and as to the effectiveness of techniques to reduce its impact on devices. However, the methodology of this study is discussed in detail to aid in the planning of future experiments. Authors' industrial affiliations: S.B. Felch, Varian Research Center, 611 Hansen Way, Palo Alto, CA 94303, USA; L.A. Larson, National Semiconductor Corp., P.O. Box 58090, Santa Clara, CA 95052-8090, USA; M.I. Current, Applied Materials, 3050 Bowers Ave., Santa Clara, CA 95054, USA; D.W. Lindsey, Eaton/NOVA, 931 Benicia Ave, Sunnyvale, CA 94086, USA.

  13. High-current and low acceleration voltage arsenic ion implanted polysilicon-gate and source-drain electrode Si mos transistor

    International Nuclear Information System (INIS)

    Saito, Yasuyuki; Sugimura, Yoshiro; Sugihara, Michiyuki

    1993-01-01

    The fabrication process of high current arsenic (As) ion implanted polysilicon (Si) gate and source drain (SD) electrode Si n-channel metal oxide-semiconductor field effect transistor (MOSFET) was examined. Poly Si film n-type doping was performed by using high current (typical current: 2mA) and relatively low acceleration voltage (40keV) As ion implantation technique (Lintott series 3). It was observed that high dose As implanted poly Si films as is show refractoriness against radical fluorine excited by microwave. Using GCA MANN4800 (m/c ID No.2, resist: OFPR) mask pattern printing technique, the high current As ion implantation technique and radical fluorine gas phase etching (Chemical dry etching: CDE) technique, the n-channel Poly Si gate (ρs = ≅100Ω/□) enhancement MQSFETs(ρs source drain = ≅50Ω/□, SiO 2 gate=380 angstrom) with off-leak-less were obtained on 3 inch Czochralski grown 2Ωcm boron doped p type wafers (Osaka titanium). By the same process, a 8 bit single chip μ-processor with 26MHz full operation was performed

  14. Upgrade program of the high current heavy ion UNILAC as an injector for FAIR

    International Nuclear Information System (INIS)

    Barth, W.; Bayer, W.; Dahl, L.; Groening, L.; Richter, S.; Yaramyshev, S.

    2007-01-01

    Presently, the GSI facility consists of the heavy ion high current linac UNILAC and the synchrotron SIS 18. For the FAIR project the existing GSI accelerator complex is foreseen to serve as an injector for up to 10 12 U 28+ particles/s on the target. For this purpose an U 28+ beam current of 15 emA inside of the SIS 18 acceptance is required from the UNILAC for the multi-turn injection to the synchrotron up to its space charge limit. Different hardware measures and careful fine tuning in all sections of the UNILAC during the last years resulted in an increase of the beam intensity of up to a factor of seven. To meet the FAIR requirements a further improvement of the beam brilliance at the synchrotron entrance of about a factor of five is necessary. Several upgrade measures are planned and are partially on the realization stage. Simultaneously experimental and numerical studies of the UNILAC are going on and directed to the optimization of the machine and to investigations of the influence of the upgrade measures to the performance of the whole accelerator

  15. Microwave quantum logic gates for trapped ions.

    Science.gov (United States)

    Ospelkaus, C; Warring, U; Colombe, Y; Brown, K R; Amini, J M; Leibfried, D; Wineland, D J

    2011-08-10

    Control over physical systems at the quantum level is important in fields as diverse as metrology, information processing, simulation and chemistry. For trapped atomic ions, the quantized motional and internal degrees of freedom can be coherently manipulated with laser light. Similar control is difficult to achieve with radio-frequency or microwave radiation: the essential coupling between internal degrees of freedom and motion requires significant field changes over the extent of the atoms' motion, but such changes are negligible at these frequencies for freely propagating fields. An exception is in the near field of microwave currents in structures smaller than the free-space wavelength, where stronger gradients can be generated. Here we first manipulate coherently (on timescales of 20 nanoseconds) the internal quantum states of ions held in a microfabricated trap. The controlling magnetic fields are generated by microwave currents in electrodes that are integrated into the trap structure. We also generate entanglement between the internal degrees of freedom of two atoms with a gate operation suitable for general quantum computation; the entangled state has a fidelity of 0.76(3), where the uncertainty denotes standard error of the mean. Our approach, which involves integrating the quantum control mechanism into the trapping device in a scalable manner, could be applied to quantum information processing, simulation and spectroscopy.

  16. Development of high-current pulsed heavy-ion-beam technology for applications to materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroaki; Ochiai, Yasushi; Masugata, Katsumi [University of Toyama, Toyama (Japan)

    2011-12-15

    Development of intense pulsed heavy ion beam technology for applications to materials processing is described. We have developed a magnetically insulated ion diode for the generation of intense pulsed metallic ion beams in which a vacuum arc plasma gun is used as the ion source. When the ion diode was successfully operated at a diode voltage of 220 kV and a diode current of 10 kA, an ion beam with an ion current density of >200 A/cm{sup 2} and a pulse duration of 40 ns was obtained. The ion composition was evaluated by using a Thomson parabola spectrometer, and the ion beam consisted of aluminum ions (Al{sup (1-3)+}) with an energy of 140 - 740 keV and protons with an energy of 160 - 190 keV; the purity was estimated to be 89%, which was much higher than that of the pulsed ion beam produced in a conventional ion diode. The development of a bipolar pulse accelerator (BPA) was reported in order to improve the purity of intense pulsed ion beams. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. When a bipolar pulse with a voltage of {+-}90 kV and a pulse duration of about 65 ns was applied to the drift tube of the BPA, the ion beam with an ion current density of 2 A/cm{sup 2} and a pulse duration of 30 ns was observed 25 mm downstream from the cathode surface, which suggested bipolar pulse acceleration.

  17. Recent studies of the ion emission from high-current PF-1000 experiments

    International Nuclear Information System (INIS)

    Skladnik-Sadowska, E.; Sadowski, M.J.; Czaus, K.; Malinowski, K.; Kwiatkowski, R.; Zebrowski, J.; Sadowski, M.J.; Karpinski, L.; Paduch, M.; Scholz, M.; Garkusha, I.E.

    2010-01-01

    The paper describes diagnostics of fast ion beams emitted from a large PF-1000 facility operated at 21...27 kV, 290...480 kJ. Those beams were measured with pinhole cameras and PM-355 nuclear track detectors, placed at different angles to the discharge axis. The measurements showed a complex spatial structure of the fast ion beams. Measurements behind an axial channel in the inner electrode have shown that some ion beams are emitted also in the upstream direction. The ion energy spectra were measured with a miniature Thomson-type spectrometer. Time-resolved measurements of ions were performed with miniature scintillation detectors placed behind a pinhole.

  18. Development of long lifetime-high current plasma cathode ion source

    International Nuclear Information System (INIS)

    Yabe, Eiji; Takayama, Kazuo; Fukui, Ryota.

    1987-01-01

    A long lifetime ion source with plasma cathode has been developed for use in ion implantation. In this ion source, a plasma of a nonreactive working gas serves as a cathode in place of a thermionic tungsten filament used in the Freeman ion source. In an applied magnetic field, the plasma cathode is convergent, i.e. filament-like; in zero magnetic field, it turns divergent and spray-like. In the latter case, the plasma exhibits a remarkable ability when the working gas has an ionization potential larger than the feed gas. By any combination of a working gas of either argon or neon and a feed gas of AsF 5 or PF 5 , the lifetime of this ion source was found to be more than 90 hours with an extraction voltage of 40 kV and the corresponding ion current density 20 mA/cm 2 . Mass spectrometry results show that this ion source has an ability of generating a considerable amount of As + and P + ions from AsF 5 and PF 5 , and hence will be useful for realizing a fully cryopumped ion implanter system. This ion source is eminently suitable for use in oxygen ion production. (author)

  19. Electron-Cloud Simulation and Theory for High-Current Heavy-Ion Beams

    International Nuclear Information System (INIS)

    Cohen, R; Friedman, A; Lund, S; Molvik, A; Lee, E; Azevedo, T; Vay, J; Stoltz, P; Veitzer, S

    2004-01-01

    Stray electrons can arise in positive-ion accelerators for heavy ion fusion or other applications as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary- electron emission. We summarize the distinguishing features of electron cloud issues in heavy-ion-fusion accelerators and a plan for developing a self-consistent simulation capability for heavy-ion beams and electron clouds. We also present results from several ingredients in this capability: (1) We calculate the electron cloud produced by electron desorption from computed beam-ion loss, which illustrates the importance of retaining ion reflection at the walls. (2) We simulate of the effect of specified electron cloud distributions on ion beam dynamics. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing mode frequencies, the centroid and shape perturbations can also have significant impact. We identify an instability associated with a resonance between the beam-envelope ''breathing'' mode and the electron perturbation. We estimate its growth rate, which is moderate (compared to the reciprocal of a typical pulse duration). One conclusion from this study is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations. (3) We report first results from a long-timestep algorithm for electron dynamics, which holds promise for efficient simultaneous solution of electron and ion dynamics

  20. Electron-cloud simulation and theory for high-current heavy-ion beams

    Directory of Open Access Journals (Sweden)

    R. H. Cohen

    2004-12-01

    Full Text Available Stray electrons can arise in positive-ion accelerators for heavy-ion fusion or other applications as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. We summarize the distinguishing features of electron-cloud issues in heavy-ion-fusion accelerators and a plan for developing a self-consistent simulation capability for heavy-ion beams and electron clouds (also applicable to other accelerators. We also present results from several ingredients in this capability. (1 We calculate the electron cloud produced by electron desorption from computed beam-ion loss, which illustrates the importance of retaining ion reflection at the walls. (2 We simulate the effect of specified electron-cloud distributions on ion beam dynamics. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing-mode frequencies, the centroid and shape perturbations can also have significant impact. We identify an instability associated with a resonance between the beam-envelope “breathing” mode and the electron perturbation. We estimate its growth rate, which is moderate (compared to the reciprocal of a typical pulse duration. One conclusion from this study is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations. (3 We report first results from a long-time-step algorithm for electron dynamics, which holds promise for efficient simultaneous solution of electron and ion dynamics.

  1. Improved Ion Resistance for III-V Photocathodes in High Current Guns

    Energy Technology Data Exchange (ETDEWEB)

    Mulhollan, Gregory, A.

    2012-11-16

    The two photocathode test systems were modified, baked and recommissioned. The first system was dedicated to ion studies and the second to electron stimulated recovery (ESR) work. The demonstration system for the electron beam rejuvenation was set up, tested and demonstrated to one of the SSRL team (Dr. Kirby) during a site visit. The requisite subsystems were transferred to SSRL, installed and photoemission studies conducted on activated surfaces following electron beam exposure. Little surface chemistry change was detected in the photoemission spectra following the ESR process. The yield mapping system for the ion (and later, the electron beam rejuvenation) studies was implemented and use made routine. Ion species and flux measurements were performed for H, He, Ne, Ar, Kr and Xe ions at energies of 0.5, 1.0 and 2.0 kV. Gas induced photoyield measurements followed each ion exposure measurement. These data permit the extraction of photoyield induced change per ion (by species) at the measured energies. Electron beam induced rejuvenation was first demonstrated in the second chamber with primary electron beam energy and dependency investigations following. A Hiden quadrupole mass spectrometer for the electron stimulated desorption (ESD) measurements was procured. The UHV test systems needed for subsequent measurements were configured, baked, commissioned and utilized for their intended purposes. Measurements characterizing the desorption products from the ESD process and secondary electron (SE) yield at the surfaces of negative electron affinity GaAs photocathodes have been performed. One US Utility Patent was granted covering the ESR process.

  2. Developmental activities of the 18 GHz high temperature superconducting ECR ion source, PKDELIS, for the high current injector at IUAC

    International Nuclear Information System (INIS)

    Rodrigues, G.; Lakshmy, P.S.; Mathur, Y.; Ahuja, R.; Dutt, R.N.; Rao, U.K.; Mandal, A.; Kanjilal, D.; Roy, A.

    2011-01-01

    Various developmental activities of the 18 GHz High Temperature Superconducting ECR Ion Source, PKDELIS have been carried out as a part of the High Current Injector programme. Emittance measurements using a simple technique has given important inputs for the design of downstream accelerators like RFQ, DTL and low beta cavities. The techniques allows for emittance matching by varying the emittance parameters to match with the acceptance of the accelerators. X-ray Beamstrahlung measurements from ECR plasma has shown that it is a diagnostic tool to optimize the production of highly charged ions. The ion optics through the low energy beam transport section has been benchmarked with various codes and given a handle to optimize the transmission. New techniques to improve the extraction efficiency of highly charged ions has been developed. (author)

  3. High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Y., E-mail: y.hirano@aist.go.jp, E-mail: hirano.yoichi@phys.cst.nihon-u.ac.jp [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); College of Science and Technologies, Nihon University, Chiyodaku, Tokyo 101-0897 (Japan); Kiyama, S.; Koguchi, H. [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Fujiwara, Y.; Sakakita, H. [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Department of Engineering Mechanics and Energy, University of Tsukuba, Ibaraki 305-8577 (Japan)

    2015-11-15

    A high current density (≈3 mA/cm{sup 2}) hydrogen ion beam source operating in an extremely low-energy region (E{sub ib} ≈ 150–200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E{sub ib} is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

  4. Collective acceleration of electrons and ions in a high current relativistic electron beam. Final report

    International Nuclear Information System (INIS)

    Nation, J.A.

    1996-01-01

    The original purpose of this research was an investigation into the use of slow space charge waves on weakly relativistic electron beams for ion acceleration. The work had three main objectives namely, the development of a suitable ion injector, the growth and study of the properties of slow space charge waves on an electron beam, and a combination of the two components parts into a suitable proof of principle demonstration of the wave accelerator. This work focusses on the first two of these objectives

  5. Multicomponent ion transport in a mono and bilayer cation-exchange membrane at high current density

    NARCIS (Netherlands)

    Moshtari Khah, S.; Oppers, N.A.W.; de Groot, M.T.; Keurentjes, J.T.F.; Schouten, J.C.; van der Schaaf, J.

    2017-01-01

    This work describes a model for bilayer cation-exchange membranes used in the chlor-alkali process. The ion transport inside the membrane is modeled with the Nernst–Planck equation. A logistic function is used at the boundary between the two layers of the bilayer membrane to describe the change in

  6. Nernst-Planck modeling of multicomponent ion transport in a Nafion membrane at high current density

    NARCIS (Netherlands)

    Moshtari Khah, S.; Oppers, N.A.W.; de Groot, M.T.; Keurentjes, J.T.F.; Schouten, J.C.; van der Schaaf, J.

    A mathematical model of multicomponent ion transport through a cation-exchange membrane is developed based on the Nernst–Planck equation. A correlation for the non-linear potential gradient is derived from current density relation with fluxes. The boundary conditions are determined with the Donnan

  7. [Atomic/ionic fluorescence in microwave plasma torch discharge with excitation of high current and microsecond pulsed hollow cathode lamp: Ca atomic/ionic fluorescence spectrometry].

    Science.gov (United States)

    Gong, Zhen-bin; Liang, Feng; Yang, Peng-yuan; Jin, Qin-han; Huang, Ben-li

    2002-02-01

    A system of atomic and ionic fluorescence spectrometry in microwave plasma torch (MPT) discharge excited by high current microsecond pulsed hollow cathode lamp (HCMP HCL) has been developed. The operation conditions for Ca atomic and ionic fluorescence spectrometry have been optimized. Compared with atomic fluorescence spectrometry (AFS) in argon microwave induced plasma (MIP) and MPT with the excitation of direct current and conventional pulsed HCL, the system with HCMP HCL excitation can improve AFS and ionic fluorescence spectrometry (IFS) detection limits in MPT atomizer and ionizer. Detection limits (3 sigma) with HCMP HCL-MPT-AFS/IFS are 10.1 ng.mL-1 for Ca I 422.7 nm, 14.6 ng.mL-1 for Ca II 393.4 nm, and 37.4 ng.mL-1 for Ca II 396.8 nm, respectively.

  8. Generation and acceleration of high-current annular electron beam in linear induction accelerator and generation of the power microwave radiation from Cherenkov TWT

    International Nuclear Information System (INIS)

    Abubakirov, E.V.; Arkhipov, O.V.; Bobyleva, L.V.

    1990-01-01

    The section of linear induction accelerator (LIA) with a strong guiding magnetic field (up to 1.5 T), with output beam power up to 2 GW and beam pulse duration 60 ns is created and investigated by experiment. The beam energy gain is equal to 10 keV/sm with explosive emission is used; the large length of the beam propagation (1.5 m) without spolling of the beam with high beam energy gain has been established. The microwave radiation power about 30-100 MW has achieved from relativistic Cherenkov travelling wave tube with high exponential gain on the basis of LIA and high-current diode

  9. Development of a high-current ion source with slit beam extraction for neutral beam injector of VEST

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Bong-ki; Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr; An, Young-Hwa; Park, Jong-Yoon; Hwang, Y.S.

    2015-10-15

    Highlights: • A high-current ion source is developed for NBI system of VEST. • A cold-cathode electron gun is employed to produce primary electrons. • A hemi-cylindrical discharge chamber with cusp magnetic field is used. • Plasma density is measured to be 2 × 10{sup 18} m{sup −3} near the extraction aperture. • NBI power of 90 kW with beam energy of 20 keV is expected to be achieved. - Abstract: A high-current pulsed ion source has been developed for the neutral beam injector of the VEST (Versatile Experiment Spherical Torus) to accommodate high-beta fusion plasma experiments. The ion source consists of two parts: an electron gun for supplying sufficient primary electrons by cold-cathode arc discharge and a hemi-cylindrical discharge chamber where uniform, high-density plasma generated by the primary electrons is confined by multi-cusp magnetic field. A pulse forming network is also developed to drive high current of ∼1 kA to sustain the cold-cathode discharge in the electron gun up to 10 ms. Diagnostics with a triple probe in the discharge chamber shows that a hydrogen plasma whose density is as high as 1 × 10{sup 18} m{sup −3} can be obtained near extraction slits at the gas pressure lower than 0.5 Pa. This value is estimated to be sufficient to deposit a heating power of 90 kW to the VEST plasma when the appropriate extraction through slits with 20 cm{sup 2} in area and acceleration of ion beams up to 20 kV are fulfilled.

  10. Beam instability during high-current heavy-ion beam transport

    International Nuclear Information System (INIS)

    Kikuchi, T.; Someya, T.; Kawata, S.; Nakajima, M.; Horioka, K.

    2005-01-01

    In driver system for heavy ion inertial fusion, beam dynamics is investigated by particle-in-cell simulations during final beam bunching. The particle simulations predict that the beam is transported with the localized transverse charge distribution induced by the strong space charge effect. The calculation results also show that the emittance growth during the longitudinal bunch compression for various particle distributions at the initial conditions and with two types of transverse focusing model, which are a continuous focusing and an alternating gradient focusing lattice configurations. (author)

  11. Present status on the ion collective acceleration and high-current beam transport in the Lebedev's Physical Institute USSR

    International Nuclear Information System (INIS)

    Kolomenskij, A.A.

    1982-01-01

    The results of investigations into the ion collective acceleration and transport of high-current electron beams (HCEB) in vacuum channels with dielectric walls (VCDW) are presented. The physical principle of transport is in the partial neutralization of spatial charge of electrons with ions escaped from the prewall plasma and the compression of the beam with its own magnetic field. A problem of obtaining the intensive beams of negative ions in diode with magnetic isolation is considered. The mechanism of ion acceleration in VCDW is considered. It is shown that there are two regions with different mechanisms of acceleration. In the first region (''plasma'') ion acceleration in the quasipotential HCEB field up to energy of the order of the electron energy takes place. In the second region (''beam'') the acceleration takes place in the wave fields that can be excited due to the mechanism of the two-beam type instability. The mechanism of ion acceleration in direct electron beams is considered. This mechanism is based on the concept of relaxation oscillations of the virtual cathode and corresponding the reconstruction of the spatial charge distribution

  12. In situ beam angle measurement in a multi-wafer high current ion implanter

    International Nuclear Information System (INIS)

    Freer, B.S.; Reece, R.N.; Graf, M.A.; Parrill, T.; Polner, D.

    2005-01-01

    Direct, in situ measurement of the average angle and angular content of an ion beam in a multi-wafer ion implanter is reported for the first time. A new type of structure and method are described. The structures are located on the spinning disk, allowing precise angular alignment to the wafers. Current that passes through the structures is known to be within a range of angles and is detected behind the disk. By varying the angle of the disk around two axes, beam current versus angle is mapped and the average angle and angular spread are calculated. The average angle measured in this way is found to be consistent with that obtained by other techniques, including beam centroid offset and wafer channeling methods. Average angle of low energy beams, for which it is difficult to use other direct methods, is explored. A 'pencil beam' system is shown to give average angle repeatability of 0.13 deg. (1σ) or less, for two low energy beams under normal tuning variations, even though no effort was made to control the angle

  13. Operating experience with a high-current Cs+1 injector for heavy-ion fusion

    International Nuclear Information System (INIS)

    Chupp, W.; Faltens, A.; Herrmannsfeldt, W.

    1981-03-01

    The construction and assembly of a Cs ion injector consisting of a pulsed source and 3 pulsed drift tubes has been complete since April 1980. The measurement program, underway since then to characterize the beam, has been interspersed with the development of diagnostic equipment. The Cs contact ionization source and each of the 3 drift tubes are driven by 500 kV Marx generators. The injector has been operated reliably at 300 kV/stage at a repetition rate of 1 pulse/4 sec. About 10 5 pulses have been accumulated. The space charge limited diode and drift tube acceleration system were designed with the aid of the EGUN code of Herrmannsfeldt. Measurements of the beam envelope have been made by means of a movable biased charge collector. Good agreement with the EGUN calculation is found. Measurements of the beam emittance have been made at the exit of the third drift tube. The normalized emittance π epsilon N = 2 x 10 -6 π m-rad is of better optical quality than that required for further acceleration and transport in a Heavy Ion Fusion (HIF) Induction Linac Driver

  14. Manipulation of high-current pulses for heavy-ion fusion

    International Nuclear Information System (INIS)

    Sharp, W.M.; Callahan, D.A.; Griedman, A.; Grote, D.P.

    1996-01-01

    For efficient induction-driven heavy-ion fusion, the current profile along a pulse must be modified in a non-selfsimilar manner between the accelerator and the target. In the accelerator, the pulse should have a duration of at least 50 ns in order to make efficient use of the induction cores, and the current should by nearly uniform along the pulse to minimize the aperture. In contrast, the optimal current profile on target consists of a main pulse of about 10 ns preceded by a longer low-current 'foot.' This pulse-shape manipulation must be carried out at the final pulse energy (5-10 GeV for 200 amu ions) in the presence of a large nonlinear longitudinal space-charge field. A straightforward method is presented here for doing the required pulse shaping. Induction-ceU voltages are generated using idealized beam profiles both in the accelerator and on target, and they are verified and checked for error sensitivity using the fluid/envelope code CIRCE

  15. Microwave chemistry: Effect of ions on dielectric heating in microwave ovens

    Directory of Open Access Journals (Sweden)

    Jamil Anwar

    2015-01-01

    Full Text Available To understand the interactions of microwaves with dielectric materials and their conversion to thermal energy in aqueous systems, the effect of ionic concentration has been studied. Aqueous solutions of inorganic ions were exposed to microwaves (2.45 GHz in a modified oven under identical conditions. Difference in solution temperatures with reference to pure (deionized water was monitored in each case. A significant decrease in the temperature was observed with an increase in the quantity of ions. Experiments were repeated with several inorganic ions varying in size and charge. The information can be helpful in understanding the role of ions during dielectric heating.

  16. Very high-current propagation in the ion-focused to collision-dominated regime

    International Nuclear Information System (INIS)

    Sanford, T.W.L.; Welch, D.R.; Mock, R.C.

    1994-01-01

    Measurements and analysis show that the 13 TW, Hermes-III [J. J. Ramirez et al., Digest of Technical Papers, 6th IEEE Pulsed Power Conference (Institute of Electrical and Electronic Engineers, New York, 1987), p. 294], pulsed, electron beam has two windows of stable transport in long drift cells filled with N 2 gas terminated by a bremsstrahlung producing target: a low-pressure window (between ∼1 and ∼100 mTorr) that is dominated by propagation in the semicollisionless ion-focused regime (IFR), and a high-pressure window (between ∼1 and ∼100 Torr) that is dominated by propagation in the resistive collisional regime. In the transition region between the two windows, beam plasma--electron instabilities significantly disrupt propagation. Propagation in both regimes (the IFR at early time and the collisional at later time) is observed from ∼5 to ∼100 mTorr, which produces two distinct bremsstrahlung pulses from the single injected beam pulse. As the pressure increases, two-stream instabilities terminate IFR propagation and the associated bremsstrahlung pulse earlier and earlier in time. Above 5 mTorr, the instability is sufficiently quenched by gas collisions that propagation in the collisional regime back in the beam body occurs, leading to a second propagation and associated bremsstrahlung pulse. Above 200 mTorr, the gas breaks down too rapidly for a significant IFR pulse to form, and for higher pressures only a single pulse in the collisional regime is propagated. Reasonable stability in the collisional regime is not achieved until pressures exceed 1 Torr

  17. [Atomic/ionic fluorescence in microwave plasma torch discharge excited by high current microsecond pulsed hollow cathode lamp-europium atomic/ionic fluorescence spectrometry].

    Science.gov (United States)

    Gong, Z; Liang, F; Yang, P; Jin, Q; Huang, B

    1999-06-01

    Eu atomic and ionic fluorescence spectrometry in microwave plasma torch discharge excited by high current microsecond pulsed hollow cathode lamp (HCMP HCL-MPT AFS/IFS) was studied. Operating conditions were optimized. The best detection limits for AFS and IFS obtained with a desolvated ultrasonic nebulization system were 42.0 ng/mL for Eu I 462.7 nm and 21.8 ng/mL for Eu II 381.97 nm, respectively, both were better than those given by the instruction manual of a Baird ICP AFS-2000 spectrometer using pneumatic concentric nebulizer with desolvation for AFS, but were significantly higher than those obtained by using the Baird spectrometer with a mini-monochromator and a ultrasonic nebulzer system.

  18. Optimal conditions for high current proton irradiations at the university of Wisconsin's ion beam laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Wetteland, C. J.; Field, K. G.; Gerczak, T. J. [Materials Science Program, University of Wisconsin, Madison, WI 53706 (United States); Eiden, T. J.; Maier, B. R.; Albakri, O.; Sridharan, K.; Allen, T. R. [Department of Engineering Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2013-04-19

    The National Electrostatics Corporation's (NEC) Toroidal Volume Ion Source (TORVIS) source is known for exceptionally high proton currents with minimal service downtime as compared to traditional sputter sources. It has been possible to obtain over 150{mu}A of proton current from the source, with over 70{mu}A on the target stage. However, beam fluxes above {approx}1 Multiplication-Sign 10{sup 17}/m2-s may have many undesirable effects, especially for insulators. This may include high temperature gradients at the surface, sputtering, surface discharge, cracking or even disintegration of the sample. A series of experiments were conducted to examine the role of high current fluxes in a suite of ceramics and insulating materials. Results will show the optimal proton irradiation conditions and target mounting strategies needed to minimize unwanted macro-scale damage, while developing a procedure for conducting preliminary radiation experiments.

  19. Effect of resonant microwave power on a PIG ion source

    International Nuclear Information System (INIS)

    Brown, I.G.; Galvin, J.E.; Gavin, B.F.; MacGill, R.A.

    1984-08-01

    We have investigated the effect of applying microwave power at the electron cyclotron frequency on the characteristics of the ion beam extracted from a hot-cathode PIG ion source. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and it is possible that the technique may find application in situations where beam quiescence is important. 29 references, 2 figures

  20. Design of a Solenoid Magnet for a Microwave Ion Source

    International Nuclear Information System (INIS)

    Cho, Yong Sub; Kwon, Hyeok Jung; Kim, Dae Il

    2011-01-01

    A microwave ion source has many advantages, such as long-life time, low emittance, high brightness, and compactness. Also it is a big merit that 2.45GHz rf systems are easily available and inexpensive. Due to the reasons microwave ion sources are very attractive for industrial applications. But microwave ion sources need a solenoid magnet which is usually an electromagnet with a DC current power supply. The electromagnet solenoids of microwave ion sources can be installed in two methods. The first method is to use isolation transformer to supply electrical power to DC current power supply for the magnets. In this case the magnet is compact because it has the same potential with the extraction voltage. The second method is to put an electrical insulator, such as G10, between ion sources and magnets. In this case the solenoid magnet is bigger than one in the first method, especially for higher extraction voltage, because the space for the insulator is required. Permanent magnets can be a good candidate to make microwave ion source more compact. But it is difficult to control the magnetic field profile and the magnetic flux density for the permanent magnet solenoids. Due to the reason, in the case that the best performances in many operating conditions should be achieved by adjusting the profile and strength of the solenoid, electromagnet is better than permanent magnet. But in the case of industrial applications where operating conditions is usually fixed and the compactness is required, permanent magnet is better choice to build an ion source

  1. Electron cyclotron resonance ion source for high currents of mono- and multicharged ion and general purpose unlimited lifetime application on implantation devices

    Science.gov (United States)

    Bieth, C.; Bouly, J. L.; Curdy, J. C.; Kantas, S.; Sortais, P.; Sole, P.; Vieux-Rochaz, J. L.

    2000-02-01

    The electron cyclotron resonance (ECR) ion sources were originally developed for high energy physic applications. They are used as injectors on linear accelerators and cyclotrons to further increase the particle energy via high charge state ions. This ECR technology is well suited for sources placed on a high voltage platform where ac power available is limited by insulated transformers. The PANTECHNIK family of ion source with its wide range of ion beam (various charge states with various beam currents) offers new possibilities and perspectives in the field of ion implantation. In addition to all these possibilities, the PANTECHNIK ion sources have many other advantages like: a very long lifetime without maintenance expense, good stability, efficiency of ionization close to 100% (this improves the lifetime of the pumping system and other equipment), the possibility of producing ion beams with different energies, and a very good reproducibility. The main characteristics of sources like Nanogan or SuperNanogan will be recalled. We will especially present the results obtained with the new Microgan 10 GHz source that can be optimized for the production of high currents of monocharged ion, including reactive gas like BF3 (2 mA e of B+) or medium currents of low charge state like 0.5 mA e of Ar4+. The latest results obtained with Microgan 10 GHz show that it is possible to drive the source up to 30 mA e of total current, with an emittance of 150 π mm mrad at 40 kV and also to maintain the production of multicharged ions like Ar8+.

  2. A Microwave Driven Ion Source for Continuous-Flow AMS (Abstract)

    International Nuclear Information System (INIS)

    Wills, J.; Schneider, R.J.; Reden, K.F. von; Hayes, J.M.; Roberts, M.L.; Benthien, A.

    2005-01-01

    A microwave-driven, gas-fed ion source originally developed as a high-current positive ion injector for a Tandem accelerator at Chalk River has been the subject of a three-year development program at the Woods Hole Oceanographic Institution NOSAMS facility. Off-line tests have demonstrated positive carbon currents of 1 mA and negative carbon currents of 80 μA from CO2 gas feed. This source and a magnesium charge-exchange canal were coupled to the recombinator of the NOSAMS Tandetron for on-line tests, with the source fed with reference gasses and a combustion device.The promising results obtained have prompted the redesign of the microwave source for use as an on-line, continuous-flow injector for a new AMS facility under construction at NOSAMS. The new design is optimized for best transmission of the extracted positive-ion beam through the charge-exchange canal and for reliable operation at 40 kV extraction voltage. Other goals of the re-design include improved lifetime of the microwave window and the elimination of dead volumes in the plasma generator that increase sample hold-up time.This talk will include a summary of results obtained to date at NOSAMS with the Chalk River source and a detailed description of the new design

  3. Spatial and Time Dynamics of Non-Linear Vortices in Plasma Lens for High-Current Ion Beam Focusing

    Science.gov (United States)

    Goncharov, Alexei A.; Maslov, Vasyl I.; Onishchenko, Ivan N.; Tretyakov, Vitalij N.

    2002-11-01

    It is known from numerical simulation (see, for example, [1]) and from experiments (see, for example, [2]), that an electron density bunches as discrete vortices are long - living structures in vacuum. However, in laboratory experiments [2] it has been shown that the vortices are changed faster, when they are submersed in electrons, distributed around them. The charged plasma lens intended for a focussing of high-current ion beams, has the same crossed configuration of a radial electrical and longitudinal magnetic field [3], as only electron plasma. In this lens the vortical turbulence is excited [3]. The vortex - bunch and vortex - hole are rotated in the inverse directions in system of their rest. The instability development in initially homogeneous plasma causes that the vortices are excited by pairs. Namely, if the vortex - bunch of electrons is generated, near the vortex - hole of electrons is also generated. It is shown, that in nonuniform plasma the vortices behave is various in time. Namely, the vortex - bunch goes to area of larger electron density, and the vortex - hole goes to area of smaller electron density. The speed of the vortex - hole is less than speed of the vortex - bunch. It is shown, that the electron vortices, generated in the plasma lens, can result in to formation of spiral distribution of electron density. The physical mechanism of coalescence of electron vortices - bunches is proposed. 1.Driscoll C.F. et al. Plasma Phys. Contr. Fus. Res. 3 (1989) 507. 2.Kiwamoto Y. et al. Non-neutral plasma physics. Princeton. 1999. P. 99-105. 3.Goncharov A. et al. Plasma Phys. Rep. 20 (1994) 499.

  4. Theory and simulation of ion noise in microwave tubes

    Science.gov (United States)

    Manheimer, W. M.; Freund, H. P.; Levush, B.; Antonsen, T. M.

    2001-01-01

    Since there is always some ambient gas in electron beam devices, background ionization is ubiquitous. For long pulse times, the electrostatic potentials associated with this ionization can reach significant levels and give rise to such observed phenomena as phase noise in microwave tubes. This noise is usually associated with the motion of ions in the device; therefore, it is called ion noise. It often manifests itself as a slow phase fluctuation on the output signal. Observations of noise in microwave tubes such as coupled-cavity traveling wave tubes (CC-TWTs) and klystrons have been discussed in the literature. In this paper, a hybrid model is discussed in which the electron beam is described by the beam envelope equation, and the ions generated by beam ionization are treated as discrete particles using the one-dimensional equations of motion. The theoretical model provides good qualitative as well as reasonable quantitative insight into the origin of ion noise phenomena. The numerical results indicate that the model reproduces the salient features of the phase oscillations observed experimentally. That is, the scaling of the frequency of the phase oscillations with gas pressure in the device and the sensitive dependence of the phase oscillations on the focusing magnetic field. Two distinct time scales are observed in simulation. The fastest time scale oscillation is related to the bounce motion of ions in the axial potential wells formed by the scalloping of the electron beam. Slower sawtooth oscillations are observed to correlate with the well-to-well interactions induced by the ion coupling to the electron equilibrium. These oscillations are also correlated with ion dumping to the cathode or collector. As a practical matter, simulations indicate that the low frequency oscillations can be reduced significantly by using a well-matched electron beam propagating from the electron gun into the interaction circuit.

  5. Theory and simulation of ion noise in microwave tubes

    International Nuclear Information System (INIS)

    Manheimer, W.M.; Freund, H.P.; Levush, B.; Antonsen, T.M. Jr.

    2001-01-01

    Since there is always some ambient gas in electron beam devices, background ionization is ubiquitous. For long pulse times, the electrostatic potentials associated with this ionization can reach significant levels and give rise to such observed phenomena as phase noise in microwave tubes. This noise is usually associated with the motion of ions in the device; therefore, it is called ion noise. It often manifests itself as a slow phase fluctuation on the output signal. Observations of noise in microwave tubes such as coupled-cavity traveling wave tubes (CC-TWTs) and klystrons have been discussed in the literature. In this paper, a hybrid model is discussed in which the electron beam is described by the beam envelope equation, and the ions generated by beam ionization are treated as discrete particles using the one-dimensional equations of motion. The theoretical model provides good qualitative as well as reasonable quantitative insight into the origin of ion noise phenomena. The numerical results indicate that the model reproduces the salient features of the phase oscillations observed experimentally. That is, the scaling of the frequency of the phase oscillations with gas pressure in the device and the sensitive dependence of the phase oscillations on the focusing magnetic field. Two distinct time scales are observed in simulation. The fastest time scale oscillation is related to the bounce motion of ions in the axial potential wells formed by the scalloping of the electron beam. Slower sawtooth oscillations are observed to correlate with the well-to-well interactions induced by the ion coupling to the electron equilibrium. These oscillations are also correlated with ion dumping to the cathode or collector. As a practical matter, simulations indicate that the low frequency oscillations can be reduced significantly by using a well-matched electron beam propagating from the electron gun into the interaction circuit

  6. Effect of high energy electrons on H⁻ production and destruction in a high current DC negative ion source for cyclotron.

    Science.gov (United States)

    Onai, M; Etoh, H; Aoki, Y; Shibata, T; Mattei, S; Fujita, S; Hatayama, A; Lettry, J

    2016-02-01

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments.

  7. High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc

    International Nuclear Information System (INIS)

    Yushkov, Georgy Yu.; Anders, A.

    2008-01-01

    Metal ions were extracted from pulsed discharge plasmas operating in the transition region between vacuum spark (transient high voltage of kV) and vacuum arc (arc voltage ∼ 20 V). At a peak current of about 4 kA, and with a pulse duration of 8 (micro)s, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with ions of charge states as high as 10 present. For gold we found traces of charge state 11, with the highest average charge state of 7.25. At currents higher than 5 kA, non-metallic contaminations started to dominate the ion beam, preventing further enhancement of the metal charge states

  8. Electron cyclotron resonance microwave ion sources for thin film processing

    International Nuclear Information System (INIS)

    Berry, L.A.; Gorbatkin, S.M.

    1990-01-01

    Plasmas created by microwave absorption at the electron cyclotron resonance (ECR) are increasingly used for a variety of plasma processes, including both etching and deposition. ECR sources efficiently couple energy to electrons and use magnetic confinement to maximize the probability of an electron creating an ion or free radical in pressure regimes where the mean free path for ionization is comparable to the ECR source dimensions. The general operating principles of ECR sources are discussed with special emphasis on their use for thin film etching. Data on source performance during Cl base etching of Si using an ECR system are presented. 32 refs., 5 figs

  9. Experiments investigating the effects of the accelerating gap voltage pulse on the ion focused (IFR) high current electron recirculators

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R.; Turman, B.N.; Prestwich, K.R.; Wells, J.

    1991-01-01

    The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for an open-ended, spiral recirculating electron linear accelerator. It dictates the number of allowable beam recirculations through the gap. In the case of a racetrack configuration, it is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. It was established that pulsing the accelerating gap perturbs the IFR channel. However, for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition, cusp fields positioned upstream and downstream from the gap prevent it from perturbing the IFR channel. 4 refs., 5 figs., 1 tab

  10. Experiments investigating the effects of the accelerating gap voltage pulse on the ion focused (IFR) high current electron recirculators

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R. Turnman, B.N.; Prestwich, K.R.; Wells, J.

    1991-01-01

    The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for an open-ended, spiral recirculating electron linear accelerator. It dictates the number of allowable beam recirculations through the gap. In the case of a racetrack configuration, its is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. It was established that pulsing the accelerating gap perturbs the IFR channel. However, for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition, cusp fields positioned upstream and downstream from the gap prevent it from perturbing the IFR channel

  11. Simulation of 10 A electron-beam formation and collection for a high current electron-beam ion source

    International Nuclear Information System (INIS)

    Kponou, A.; Beebe, E.; Pikin, A.; Kuznetsov, G.; Batazova, M.; Tiunov, M.

    1998-01-01

    Presented is a report on the development of an electron-beam ion source (EBIS) for the relativistic heavy ion collider at Brookhaven National Laboratory (BNL) which requires operating with a 10 A electron beam. This is approximately an order of magnitude higher current than in any existing EBIS device. A test stand is presently being designed and constructed where EBIS components will be tested. It will be reported in a separate paper at this conference. The design of the 10 A electron gun, drift tubes, and electron collector requires extensive computer simulations. Calculations have been performed at Novosibirsk and BNL using two different programs, SAM and EGUN. Results of these simulations will be presented. copyright 1998 American Institute of Physics

  12. Simulation of 10 A electron-beam formation and collection for a high current electron-beam ion source

    Science.gov (United States)

    Kponou, A.; Beebe, E.; Pikin, A.; Kuznetsov, G.; Batazova, M.; Tiunov, M.

    1998-02-01

    Presented is a report on the development of an electron-beam ion source (EBIS) for the relativistic heavy ion collider at Brookhaven National Laboratory (BNL) which requires operating with a 10 A electron beam. This is approximately an order of magnitude higher current than in any existing EBIS device. A test stand is presently being designed and constructed where EBIS components will be tested. It will be reported in a separate paper at this conference. The design of the 10 A electron gun, drift tubes, and electron collector requires extensive computer simulations. Calculations have been performed at Novosibirsk and BNL using two different programs, SAM and EGUN. Results of these simulations will be presented.

  13. Electric field measurement in microwave discharge ion thruster with electro-optic probe.

    Science.gov (United States)

    Ise, Toshiyuki; Tsukizaki, Ryudo; Togo, Hiroyoshi; Koizumi, Hiroyuki; Kuninaka, Hitoshi

    2012-12-01

    In order to understand the internal phenomena in a microwave discharge ion thruster, it is important to measure the distribution of the microwave electric field inside the discharge chamber, which is directly related to the plasma production. In this study, we proposed a novel method of measuring a microwave electric field with an electro-optic (EO) probe based on the Pockels effect. The probe, including a cooling system, contains no metal and can be accessed in the discharge chamber with less disruption to the microwave distribution. This method enables measurement of the electric field profile under ion beam acceleration. We first verified the measurement with the EO probe by a comparison with a finite-difference time domain numerical simulation of the microwave electric field in atmosphere. Second, we showed that the deviations of the reflected microwave power and the beam current were less than 8% due to inserting the EO probe into the ion thruster under ion beam acceleration. Finally, we successfully demonstrated the measurement of the electric-field profile in the ion thruster under ion beam acceleration. These measurements show that the electric field distribution in the thruster dramatically changes in the ion thruster under ion beam acceleration as the propellant mass flow rate increases. These results indicate that this new method using an EO probe can provide a useful guide for improving the propulsion of microwave discharge ion thrusters.

  14. Optimization of the plasma parameters for the high current and uniform large-scale pulse arc ion source of the VEST-NBI system

    International Nuclear Information System (INIS)

    Jung, Bongki; Park, Min; Heo, Sung Ryul; Kim, Tae-Seong; Jeong, Seung Ho; Chang, Doo-Hee; Lee, Kwang Won; In, Sang-Ryul

    2016-01-01

    Highlights: • High power magnetic bucket-type arc plasma source for the VEST NBI system is developed with modifications based on the prototype plasma source for KSTAR. • Plasma parameters in pulse duration are measured to characterize the plasma source. • High plasma density and good uniformity is achieved at the low operating pressure below 1 Pa. • Required ion beam current density is confirmed by analysis of plasma parameters and results of a particle balance model. - Abstract: A large-scale hydrogen arc plasma source was developed at the Korea Atomic Energy Research Institute for a high power pulsed NBI system of VEST which is a compact spherical tokamak at Seoul national university. One of the research target of VEST is to study innovative tokamak operating scenarios. For this purpose, high current density and uniform large-scale pulse plasma source is required to satisfy the target ion beam power efficiently. Therefore, optimizing the plasma parameters of the ion source such as the electron density, temperature, and plasma uniformity is conducted by changing the operating conditions of the plasma source. Furthermore, ion species of the hydrogen plasma source are analyzed using a particle balance model to increase the monatomic fraction which is another essential parameter for increasing the ion beam current density. Conclusively, efficient operating conditions are presented from the results of the optimized plasma parameters and the extractable ion beam current is calculated.

  15. On-line measurement of microwave power in ECR ion source

    International Nuclear Information System (INIS)

    Zhou Changgeng; Kang Wu; Hu Yonghong; Li Yan; Lou Benchao; Zu Xiulan; Xiong Riheng; Chen Junguang; Li Xiaoyun

    2005-01-01

    It is a new technology to apply an ECR ion source to the neutron generator. Because of the structure limitation, working state of the ECR ion source could not be judged by the color of gas discharging in discharge chamber. Therefore, it was hard to estimate if the ECR ion source was working properly in the neutron generator. The method to resolve the problem was described in this paper. The microwave power was measured on-line by a directional coupler and a small microwave power meter. The ion beam current could be educed from the measured incidence microwave power, and discharge state in discharge chamber could be determined. (authors)

  16. Development of a two-beam high-current ion accelerator based on Doppler effect. Final report (1994)

    International Nuclear Information System (INIS)

    Ivanov, B.I.; Yegorov, A.M.

    1995-03-01

    This Final Report presents the results of work accomplished in accordance with the Scope of Work to the Purchase Order No 4596310. The amount of works includes the following items: 1. Start of the manufacture of the Experimental Accelerating Stand (EAS)-the section for proton acceleration from 5 MeV to 8 MeV, in which RF fields are excited by an electron beam at the anomalous Doppler effect. 2. Theoretical investigation and computer simulation of field excitation and ion acceleration in the EAS. Under item 1, the EAS manufacturing is begun. To present time, a pedestal for the EAS and a stainless steel vacuum chamber for RF resonator are made (length of the chamber is about 180 cm, diameter is about 40 cm). Besides, parts of the EAS resonator with the acceleration structure are manufactured, and its assembly is begun. Under item 2, it is realized three works: calculation of increment and frequency shift of the EAS resonator excited by electron beam, calculation of the solenoid for creation of magnetic field with required spatial distribution, and theoretical investigation and computer simulation of ion acceleration in the EAS. 14 figs., 16 refs

  17. Longitudinal motion in high current ion beams: a self-consistent phase space distribution with an envelope equation

    International Nuclear Information System (INIS)

    Neuffer, D.

    1979-03-01

    Many applications of particle acceleration, such as heavy ion fusion, require longitudinal bunching of a high intensity particle beam to extremely high particle currents with correspondingly high space charge forces. This requires a precise analysis of longitudinal motion including stability analysis. Previous papers have treated the longitudinal space charge force as strictly linear, and have not been self-consistent; that is, they have not displayed a phase space distribution consistent with this linear force so that the transport of the phase space distribution could be followed, and departures from linearity could be analyzed. This is unlike the situation for transverse phase space where the Kapchinskij--Vladimirskij (K--V) distribution can be used as the basis of an analysis of transverse motion. In this paper a self-consistent particle distribution in longitudinal phase space is derived which is a solution of the Vlasov equation and an envelope equation for this solution is derived

  18. Studies on space charge neutralization and emittance measurement of beam from microwave ion source

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Anuraag; Goswami, A.; Sing Babu, P.; Srivastava, S.; Pandit, V. S., E-mail: pandit@vecc.gov.in, E-mail: vspandit12@gmail.com [Variable Energy Cyclotron Centre, 1-AF, Bidhannagar, Kolkata 700 064 (India)

    2015-11-15

    A 2.45 GHz microwave ion source together with a beam transport system has been developed at VECC to study the problems related with the injection of high current beam into a compact cyclotron. This paper presents the results of beam profile measurement of high current proton beam at different degrees of space charge neutralisation with the introduction of neon gas in the beam line using a fine leak valve. The beam profiles have been measured at different pressures in the beam line by capturing the residual gas fluorescence using a CCD camera. It has been found that with space charge compensation at the present current level (∼5 mA at 75 keV), it is possible to reduce the beam spot size by ∼34%. We have measured the variation of beam profile as a function of the current in the solenoid magnet under the neutralised condition and used these data to estimate the rms emittance of the beam. Simulations performed using equivalent Kapchinsky-Vladimirsky beam envelope equations with space charge neutralization factor are also presented to interpret the experimental results.

  19. Blueprint for a microwave trapped ion quantum computer.

    Science.gov (United States)

    Lekitsch, Bjoern; Weidt, Sebastian; Fowler, Austin G; Mølmer, Klaus; Devitt, Simon J; Wunderlich, Christof; Hensinger, Winfried K

    2017-02-01

    The availability of a universal quantum computer may have a fundamental impact on a vast number of research fields and on society as a whole. An increasingly large scientific and industrial community is working toward the realization of such a device. An arbitrarily large quantum computer may best be constructed using a modular approach. We present a blueprint for a trapped ion-based scalable quantum computer module, making it possible to create a scalable quantum computer architecture based on long-wavelength radiation quantum gates. The modules control all operations as stand-alone units, are constructed using silicon microfabrication techniques, and are within reach of current technology. To perform the required quantum computations, the modules make use of long-wavelength radiation-based quantum gate technology. To scale this microwave quantum computer architecture to a large size, we present a fully scalable design that makes use of ion transport between different modules, thereby allowing arbitrarily many modules to be connected to construct a large-scale device. A high error-threshold surface error correction code can be implemented in the proposed architecture to execute fault-tolerant operations. With appropriate adjustments, the proposed modules are also suitable for alternative trapped ion quantum computer architectures, such as schemes using photonic interconnects.

  20. Construction and characterization of a new high current ion source for research of impact of hydrogen irradiation on wall materials for use in nuclear fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Arredondo Parra, Rodrigo; Neu, Rudolf [Max Planck Institute for Plasma Physics, Garching (Germany); Technische Universitaet Muenchen, Garching (Germany); Oberkofler, Martin; Schmid, Klaus; Weghorn, Arno [Max Planck Institute for Plasma Physics, Garching (Germany)

    2016-07-01

    The HSQ (HochStromQuelle) is a high current DuoPIGatron type ion source used for research in surface properties of wall materials for nuclear fusion reactors. The existing HSQ-I will be replaced by the conceptually identical HSQ-II, currently under construction. Varying the acceleration potential and optimizing gas inflow and beam focusing grid voltage, ion currents before the deflecting magnet between 10 and 875 μA were reached for acceleration voltages of 0.7 to 8 kV. The ion beam footprint will be characterized, and ion optics will be installed before and after the deflecting magnet, capable of bending 10 keV Ar. A monoenergetic beam of a single species (e.g. D{sub 3}{sup +}) will finally be used for irradiation of samples in the separate implantation chamber at a base pressure of 10{sup -8} mbar. The energy of the impinging particles ranges from 200 eV/D to several keV/D. Fluxes of 10{sup 15} D/cm{sup 2}/s to the target are expected. The temperature of the sample is varied via electron impact heating and the sample weight can be assessed in situ by means of a magnetic suspension balance.

  1. Experimental studies of effect of high current pulse electron and carbon ion beams on high temperature Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O superconductors

    International Nuclear Information System (INIS)

    Korenev, S.A.; Sikolenko, V.V.; Chernakova, A.

    1989-01-01

    This work shows the results of the experiment on the effect of high current electron and carbon ion pulse beams irradiation on High-T c superconductors Y-Ba-Cu-O and Bi-Ca-Cu-O in vacuum (P∼5x10 -5 torr). The parameters of electron beam used in the experiment were: E∼100-300 keV, j e ∼10-1000 A/cm 2 , τ) p ∼300ns. The parameters of carbon ions used in the experiment were: E∼100-300keV j i ∼1-60A/cm, τ p ∼300ns. Experiments had shown the threshold electron beam power density for surface melting in adiabatic heat condition for Y-Ba-Cu-O ceramics up to P 0 >or approx. 10 7 W/cm 2 , and for Bi-Ca-Sr-Cu-O ceramics up to P 0 ∼4x10 6 W/cm 2 . Increasing of critical current in ∼2 times was observed in samples with a melting surface layer. The integral resistance of Y-Ba-Cu-O and Bi-Ca-Sr-Cu-O decreased in ∼2-2.5 times for electron beam irradiated samples and in ∼1.25-1.8 times for ion irradiated samples. Amorphization did not take place and stoichiometry remained after such irradiation. 6 refs.; 2 figs.; 1 tab

  2. Experimental study of high current negative ion sources D- / H-. Analysis based on the simulation of the negative ion transport in the plasma source

    International Nuclear Information System (INIS)

    Riz, D.

    1996-01-01

    In the frame of the development of a neutral beam injection system able to work the ITER tokamak (International Thermonuclear Experimental Reactor), two negative ion sources, Dragon and Kamaboko, have been installed on the MANTIS test bed in Cadarache, and studies in order to extract 20 mA/cm 2 of D - . The two production modes of negative ions have been investigated: volume production; surface production after cesium injection in the discharge. Experiments have shown that cesium seeding is necessary in order to reach the requested performances for ITER. 20 mA/cm 2 have been extracted from the Kamaboko source for an arc power density of 2.5 kW/liter. Simultaneously, a code called NIETZSCHE has been developed to simulate the negative ions transport in the source plasma, from their birth place to the extraction holes. The ion trajectory is calculated by numerically solving the 3D motion equation, while the atomic processes of destruction, of elastic collisions H - /H + and of charge exchange H - /H 0 are handled at each time step by a Monte Carlo procedure. The code allows to obtain the extraction probability of a negative ion produced at a given location. The calculations performed with NIETZSCHE have allowed to explain several phenomena observed on negative ion sources, such as the isotopic effect H - /D - and the influence of the polarisation of the plasma grid and of the magnetic filter on the negative ions current. The code has also shown that, in the type of sources contemplated for ITER, working with large arc power densities (> 1 kW/liter), only negative ions produced in volume at a distance lower that 2 cm from the plasma grid and those produced at the grid surface have a chance of being extracted. (author)

  3. Performance Test of the Microwave Ion Source with the Multi-layer DC Break

    International Nuclear Information System (INIS)

    Kim, Dae Il; Kwon, Hyeok Jung; Kim, Han Sung; Seol, Kyung Tae; Cho, Yong Sub

    2012-01-01

    A microwave proton source has been developed as a proton injector for the 100-MeV proton linac of the PEFP (Proton Engineering Frontier Project). On microwave ion source, the high voltage for the beam extraction is applied to the plasma chamber, also to the microwave components such as a 2.45GHz magnetron, a 3-stub tuner, waveguides. If microwave components can be installed on ground side, the microwave ion source can be operated and maintained easily. For the purpose, the multi-layer DC break has been developed. A multi-layer insulation has the arrangement of conductors and insulators as shown in the Fig. 1. For the purpose of stable operation as the multi-layer DC break, we checked the radiation of the insulator depending on materials and high voltage test of a fabricated multi-layer insulation. In this report, the details of performance test of the multi-layer DC break will be presented

  4. A high current high frequency ions gun; Etude et realisation d'un canon a ions du type haute frequence a debit eleve

    Energy Technology Data Exchange (ETDEWEB)

    Coutant, J; Prevot, F; Vienet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    A 10 mA protons gun has been developed for different purposes. The first part of the report studies the plasma production with a RF electromagnetic field. Then the ion extraction process is analysed with particular reference to space charge phenomena. The last part describes a three electrode electrostatic lens which focusses the beam. (author) [French] Un canon a ions capable de delivrer un faisceau de protons d'une intensite de l'ordre de 10 mA a ete developpe pour differents usages. Dans la premiere partie les problemes relatifs a la production et a l'entretien d'un plasma excite par un champ electromagnetique de haute frequence sont exposes. Ensuite les auteurs analysent le mecanisme de l'extraction des ions et montrent en particulier le role de la charge d'espace. Enfin on decrit un dispositif de focalisation electrostatique a 3 electrodes. (auteur)

  5. Properties of high current RFQ injectors

    International Nuclear Information System (INIS)

    Schempp, A.; Goethe, J.W.

    1996-01-01

    RFQ linacs are efficient, compact low energy ion structures, which have found numerous applications. They use electrical rf focusing and can capture, bunch and transmit high current ion beams. Some recent development and new projects like a heavy ion injectors for a cyclotron, and the status of the work on high current high duty factor RFQs will be discussed. (author)

  6. Properties of high current RFQ injectors

    Energy Technology Data Exchange (ETDEWEB)

    Schempp, A.; Goethe, J.W. [Frankfurt Univ. (Germany). Inst. fuer Angewandte Physik

    1996-12-31

    RFQ linacs are efficient, compact low energy ion structures, which have found numerous applications. They use electrical rf focusing and can capture, bunch and transmit high current ion beams. Some recent development and new projects like a heavy ion injectors for a cyclotron, and the status of the work on high current high duty factor RFQs will be discussed. (author) 2 refs.

  7. Effect of iron(III) ion on moso bamboo pyrolysis under microwave irradiation.

    Science.gov (United States)

    Dong, Qing; Li, Xiangqian; Wang, Zhaoyu; Bi, Yanhong; Yang, Rongling; Zhang, Jinfeng; Luo, Hongzhen; Niu, Miaomiao; Qi, Bo; Lu, Chen

    2017-11-01

    The effect of iron(III) ion on microwave pyrolysis of moso bamboo was investigated. Hydrofluoric acid washing was used as a pilot process to demineralize moso bamboo in order to eliminate the influences of the other inorganics contained in moso bamboo itself. The results indicated that the addition of iron(III) ion increased the maximal reaction temperatures under microwave condition dependent on the amount of the added iron(III) ion. The production of the non-condensable gases was promoted by the addition of iron(III) ion mainly at the expense of liquid products. Iron(III) ion exhibited the positive effect for syngas production and inhibited the formation of CO 2 and CH 4 . The formation of Fe 2 O 3 and Fe 3 O 4 was found during microwave pyrolysis and the mechanism of the two metallic oxides formation was described in this work. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. On-line measurement of the microwave power in ECR ion source

    International Nuclear Information System (INIS)

    Zhou Changgeng; Kang Wu; Hu Yonghong; Li Yan; Lou Benchao; Zu Xiulan; Xiong Riheng; Chen Junguang

    2005-01-01

    It is a new technology that ECR ion source is applied in the neutron generator. Because of effect of the structure, working state of ECR ion source could not be judged by the color of gas discharging in discharging chamber as doing in high frequency ion source. Therefore, state adjusting of ECR ion source was difficult in running of the neutron generator. The method to resolve the question is described in this paper. The micro-wave power was measured in case of running by using the method of directional coupler adding small microwave power meter. Because both were in the direct proportion, the ion beam current could be educed from microwave incidence power measured, and discharge state in discharge chamber could be judged. Finally, the neutron generator might be operated in best running state. (authors)

  9. Microwave plasma source having improved switching operation from plasma ignition phase to normal ion extraction phase

    International Nuclear Information System (INIS)

    Sakudo, N.; Abe, K.; Koike, H.; Okada, O.; Tokiguchi, K.

    1985-01-01

    In a microwave plasma source, a discharge space supplied with a microwave electric field is supplied with a DC magnetic field. A material to be ionized is introduced into the discharge space to produce plasma, whereby ions are extracted through an ion extracting system. A switch is provided for effecting through switching operation the change-over of the magnetic field applied to the discharge space from the intensity for the ignition of plasma to the intensity for ion extraction in succession to completion of the plasma ignition

  10. Axial magnetic field extraction type microwave ion source with a permanent magnet

    International Nuclear Information System (INIS)

    Ishikawa, Junzo; Takagi, Toshinori

    1984-01-01

    A new type of microwave ion source in which a permanent magnet generates an axially directed magnetic field needed for the electron cyclotron resonance was developed. The electron cyclotron resonance produces a high density plasma in the ion source. A mA-order ion beam can be extracted. Compared with usual microwave ion sources, this source has a distinguished feature in that the axially directed magnetic field is formed by use of a permanent magnet. Shape of magnetic force lines near the ion extraction aperture was carefully investigated. The extracted ion current as a function of the ion extraction voltage was measured. The experimental data are in good agreement with the theoretical line. The ion source can be heated up to 500 deg C, and extraction of the alkaline metal ions is possible. The extracted ion current for various elements are shown in the table. The current density normalized by the proton was 350-650 mA/cm 2 which was nearly equal to the upper limit of the extractable positive ion current density. The plasma density was estimated and was 2 - 3 x 10 12 cm -3 . The mass spectrum of a Cesium ion beam was obtained. A negligible amount of impurities was observed. The emittance diagram of the extracted ion beam was measured. The result shows that a low emittance and high brightness ion source is constructed. (Kato, T.)

  11. A Permanent-Magnet Microwave Ion Source for a Compact High-Yield Neutron Generator

    International Nuclear Information System (INIS)

    Waldmann, Ole; Ludewigt, Bernhard

    2010-01-01

    We present recent work on the development of a microwave ion source that will be used in a high-yield compact neutron generator for active interrogation applications. The sealed tube generator will be capable of producing high neutron yields, 5 · 10 11 n/s for D-T and ∼ 1 · 10 10 n/s for D-D reactions, while remaining transportable. We constructed a microwave ion source (2.45 GHz) with permanent magnets to provide the magnetic field strength of 87.5 mT necessary for satisfying the electron cyclotron resonance (ECR) condition. Microwave ion sources can produce high extracted beam currents at the low gas pressures required for sealed tube operation and at lower power levels than previously used RF-driven ion sources. A 100 mA deuterium/tritium beam will be extracted through a large slit (60 · 6 mm 2 ) to spread the beam power over a larger target area. This paper describes the design of the permanent-magnet microwave ion source and discusses the impact of the magnetic field design on the source performance. The required equivalent proton beam current density of 40 mA/cm 2 was extracted at a moderate microwave power of 400 W with an optimized magnetic field.

  12. High-Fidelity Trapped-Ion Quantum Logic Using Near-Field Microwaves.

    Science.gov (United States)

    Harty, T P; Sepiol, M A; Allcock, D T C; Ballance, C J; Tarlton, J E; Lucas, D M

    2016-09-30

    We demonstrate a two-qubit logic gate driven by near-field microwaves in a room-temperature microfabricated surface ion trap. We introduce a dynamically decoupled gate method, which stabilizes the qubits against fluctuating energy shifts and avoids the need to null the microwave field. We use the gate to produce a Bell state with fidelity 99.7(1)%, after accounting for state preparation and measurement errors. The gate is applied directly to ^{43}Ca^{+} hyperfine "atomic clock" qubits (coherence time T_{2}^{*}≈50  s) using the oscillating magnetic field gradient produced by an integrated microwave electrode.

  13. RIKEN 200 kV high current implanter for metal surface modification

    International Nuclear Information System (INIS)

    Iwaki, M.; Yoshida, K.; Sakudo, N.

    1985-01-01

    A high current, metal ion implanter was constructed in order to aid the formation of a new metastable surface alloy. This implanter, called a RIKEN 200 kV high current implanter, is a modified Lintott high current machine (Series III), which has the advantages of having its own microwave ion source and an extra target chamber. The microwave discharge ion source without a hot-filament has a comparatively long lifetime because the chloride ions and radicals in a plasma during discharge of metal chlorides might prevent metal to deposit on the inner walls of the discharge chamber by bombarding and chemically cleaning them. An extra target chamber for metal modification is able to control the surface composition by utilizing the sputtering effect of the ion beam during ion implantation. The use of this ion source and the extra target chamber is suggested to be suitable for the production of metallic ions and for the implantation into metals. The case study will be introduced for TI implantation into Fe. (orig.)

  14. Observation of large-amplitude ion acoustic wave in microwave-plasma interaction experiments

    International Nuclear Information System (INIS)

    Yugami, Noboru; Nishida, Yasushi

    1997-01-01

    Large amplitude ion acoustic wave, which is not satisfied with a linear dispersion relationship of ion acoustic wave, is observed in microwave-plasma interaction experiments. This ion acoustic wave is excited around critical density layer and begins to propagate to underdense region with a phase velocity one order faster than sound velocity C s , which is predicted by the linear theory, the phase velocity and the wave length of the wave decreases as it propagates. Finally, it converges to C s and strongly dumps. Diagnostic by the Faraday cup indicates that this ion acoustic wave is accompanied with a hot ion beam. (author)

  15. Blueprint for a microwave trapped-ion quantum computer

    DEFF Research Database (Denmark)

    Lekitsch, B.; Weidt, S.; Fowler, A. G.

    2017-01-01

    , are constructed using silicon microfabrication techniques and they are within reach of current technology. To perform the required quantum computations, the modules make use of long-wavelength-radiation based quantum gate technology. To scale this microwave quantum computer architecture to an arbitrary size we...

  16. Measurements of beam current density and proton fraction of a permanent-magnet microwave ion source

    Energy Technology Data Exchange (ETDEWEB)

    Waldmann, Ole; Ludewigt, Bernhard [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

    2011-11-15

    A permanent-magnet microwave ion source has been built for use in a high-yield, compact neutron generator. The source has been designed to produce up to 100 mA of deuterium and tritium ions. The electron-cyclotron resonance condition is met at a microwave frequency of 2.45 GHz and a magnetic field strength of 87.5 mT. The source operates at a low hydrogen gas pressure of about 0.15 Pa. Hydrogen beams with a current density of 40 mA/cm{sup 2} have been extracted at a microwave power of 450 W. The dependence of the extracted proton beam fraction on wall materials and operating parameters was measured and found to vary from 45% for steel to 95% for boron nitride as a wall liner material.

  17. Measurements of beam current density and proton fraction of a permanent-magnet microwave ion source.

    Science.gov (United States)

    Waldmann, Ole; Ludewigt, Bernhard

    2011-11-01

    A permanent-magnet microwave ion source has been built for use in a high-yield, compact neutron generator. The source has been designed to produce up to 100 mA of deuterium and tritium ions. The electron-cyclotron resonance condition is met at a microwave frequency of 2.45 GHz and a magnetic field strength of 87.5 mT. The source operates at a low hydrogen gas pressure of about 0.15 Pa. Hydrogen beams with a current density of 40 mA/cm(2) have been extracted at a microwave power of 450 W. The dependence of the extracted proton beam fraction on wall materials and operating parameters was measured and found to vary from 45% for steel to 95% for boron nitride as a wall liner material. © 2011 American Institute of Physics

  18. Microwave quantum logic spectroscopy and control of molecular ions

    DEFF Research Database (Denmark)

    Shi, M.; F. Herskind, P.; Drewsen, M.

    2013-01-01

    the rotational state of a molecular ion and the electronic state of an atomic ion. In this setting, the atomic ion is used for read-out of the molecular ion state, in a manner analogous to quantum logic spectroscopy based on Raman transitions. In addition to high-precision spectroscopy, this setting allows...... for rotational ground state cooling, and can be considered as a candidate for the quantum information processing with polar molecular ions. All elements of our proposal can be realized with currently available technology....

  19. Development of Remote Control and Interlock System for the PEFP Microwave Ion Source

    International Nuclear Information System (INIS)

    Song, Young Gi; Seol, Kyung Tae; Kwon, Hyeok Jung; Jang, Ji Ho; Cho, Yong Sub

    2011-01-01

    The control system for a microwave ion source as an isolated high voltage device is a main part of the PEFP distributed control system. The system is used to control two sets of microwave ion sources, the remote control and the interlock system. A VME system with an embedded Power PC CPU is used as main computer. The VME system is dedicated to control and monitoring of the ion source operation. An isolated control system has been designed and developed for remote control and monitoring of a microwave generator and various power supplies. As the source is placed on high voltage platform, optical fiber isolation has been used between the serial to optical fiber VME I/O board and the control system on the high voltage platform. These are connected through RS232 serial interface. A fast Ethernet is used to communicate between the microwave ion source control system and other control stations in the PEFP control system. EPICS toolkit is adopted to provide network programming and user interface by using EPICS Channel Access (CA)

  20. Design of high current bunching system and high power fast Faraday cup for high current LEBT at VECC

    International Nuclear Information System (INIS)

    Anuraag Misra, A.; Pandit, B.V.S.; Gautam Pal, C.

    2011-01-01

    A high current microwave ion source as described is currently operational at VECC. We are able to optimize 6.4 mA of proton current in the LEBT line of ion source. The cyclotron type of accelerators accept only a fraction of DC ion beam coming from ion source so a ion beam buncher is needed to increase the accepted current into the cyclotron. The buncher described in this paper is unique in its kind as it has to handle high beam loading power upto 400 W as it is designed to bunch few mA of proton beam currents at 80 keV beam energy. A sinusoidal quarter wave RF structure has been chosen to bunch the high current beam due to high Q achievable in comparison with other configurations. This buncher has been designed using CST Microwave studio 3D advanced code since the design frequency of our buncher is 42 MHz, we have provided the RF and vacuum window near the drift tube of buncher to avoid vacuum and multipacting problems and to keep maximum volume in air region. There is a provision of multipacting interlocks to shut off amplifier during multipacting. We have carried out a detailed electromagnetic and thermal design of the buncher in CST Microwave studio and simulated values of unloaded Q was calculated be 4000. We have estimated a power of 400 W to achieve gap (designed) voltage of 10 kV. This buncher is in advanced stage of fabrication. A high power fast Faraday cup is also designed to characterize the above mentioned high current bunching system. The fast Faraday cup is designed in 50 Ω coaxial geometry to transmit fast pulse of bunched ion beam. The design of Faraday cup was completed using ANSYS HFSS and a bandwidth of 1.75 GHz was achieved this faraday cup design was different from conventional Faraday cup design as we have designed the support and cooling lines at such a place on Faraday cup which do not disturb the electrical impedance of the cup. (author)

  1. Cryogenic high current discharges

    International Nuclear Information System (INIS)

    Meierovich, B.E.

    1994-01-01

    Z-pinches formed from frozen deuterium fibers by a rapidly rising current have enhanced stability and high neutron yield. The efforts to understand the enhanced stability and neutron yield on the basis of classical picture of Bennett equilibrium of the current channel has not given satisfactory results. The traditional approach does not take into account the essential difference between the frozen deuterium fiber Z-pinches and the usual Z-pinches such as exploding wires or classical gas-puffed Z-pinches. The very low temperature of the fiber atoms (10 K), together with the rapidly rising current, result in the coexistence of a high current channel with unionized fiber atoms for a substantial period of time. This phenomena lasts during the risetime. This approach takes into account the difference of the breakdown in a dielectric deuterium fiber and the breakdown in a metallic wire. This difference is essential to the understanding of specific features of cryogenic high current discharges. Z-pinches in frozen deuterium fibers should be considered as a qualitatively new phenomenon on the boundary of cryogenic and high current physics. It is a start of a new branch in plasma physics: the physics of cryogenic high current discharges

  2. Microwave Discharge Ion Engines onboard Hayabusa Asteroid Explorer

    International Nuclear Information System (INIS)

    Kuninaka, Hitoshi

    2008-01-01

    The Hayabusa spacecraft rendezvoused with the asteroid Itokawa in 2005 after the powered flight in the deep space by the μl0 cathode-less electron cyclotron resonance ion engines. Though the spacecraft was seriously damaged after the successful soft-landing and lift-off, the xenon cold gas jets from the ion engines rescued it. New attitude stabilization method using a single reaction wheel, the ion beam jets, and the photon pressure was established and enabled the homeward journey from April 2007 aiming the Earth return on 2010. The total accumulated operational time of the ion engines reaches 31,400 hours at the end of 2007. One of four thrusters achieved 13,400-hour space operation

  3. Generation of highly collimated high-current ion beams by skin-layer laser-plasma interaction at relativistic laser intensities

    International Nuclear Information System (INIS)

    Badziak, J.; Jablonski, S.; Glowacz, S.

    2006-01-01

    Generation of fast ion beams by laser-induced skin-layer ponderomotive acceleration has been studied using a two-dimensional (2D) two-fluid relativistic computer code. It is shown that the key parameter determining the spatial structure and angular divergence of the ion beam is the ratio d L /L n , where d L is the laser beam diameter and L n is the plasma density gradient scale length. When d L >>L n , a dense highly collimated megaampere ion (proton) beam of the ion current density approaching TA/cm 2 can be generated by skin-layer ponderomotive acceleration, even with a tabletop subpicosecond laser

  4. Sideband-cooling of trapped ytterbium-ions in the microwave regime

    International Nuclear Information System (INIS)

    Scharfenberger, Benedikt J.

    2012-01-01

    Trapped ions in a Paul trap are at present one of the most promising candidates for Quantum Information Processing (QIP). The technique that is used for this purpose in this experiment was introduced in 2001 by F. Mintert and Ch. Wunderlich. The core of this method is the use of atomic transitions in the radio- or microwave region, while a magnetic field gradient along the trap axis (where the ion chain is situated) lifts the degeneracy of the transition frequencies, such that the ions can be distinguished in frequency space; it also serves for the coupling of internal and external degrees of freedom of the ion chain. This method is called MAGIC (MAgnetic Gradient Induced Coupling). The performance of the measurements required that the apparatus of the experiment, which consists of laser sources, lambdameter, vacuum- and microwave system as well as imaging- and detection-units, had to be assembled and tested, which was an important prerequisite for the successful performance of the here described experiments. For the experiments it is advantageous to prepare the ions in an energetic state close to the motional ground state, which contributes to a reduction of the dephasing of the system while manipulating it with microwaves. By using the sideband-cooling technique to the sub-Doppler regime it is taken advantage of the fact, that ions in a linear trap are in good approximation situated in a harmonic oscillator potential and can therefore only populate discrete vibrational energy levels, whose frequency difference is given by the axial trap frequency ω z . If the system is excited by a microwave, which frequency is detuned from resonance to lower energies by a vibrational quantum, the ion looses one such phonon within each cooling-cycle. When this cycle is driven several times, the average phonon number and thus the temperature of the ion can be reduced efficiently and the ion can be initialized in a state close to the motional ground state. As sideband

  5. Studies on the coupling transformer to improve the performance of microwave ion source.

    Science.gov (United States)

    Misra, Anuraag; Pandit, V S

    2014-06-01

    A 2.45 GHz microwave ion source has been developed and installed at the Variable Energy Cyclotron Centre to produce high intensity proton beam. It is operational and has already produced more than 12 mA of proton beam with just 350 W of microwave power. In order to optimize the coupling of microwave power to the plasma, a maximally flat matching transformer has been used. In this paper, we first describe an analytical method to design the matching transformer and then present the results of rigorous simulation performed using ANSYS HFSS code to understand the effect of different parameters on the transformed impedance and reflection and transmission coefficients. Based on the simulation results, we have chosen two different coupling transformers which are double ridged waveguides with ridge widths of 24 mm and 48 mm. We have fabricated these transformers and performed experiments to study the influence of these transformers on the coupling of microwave to plasma and extracted beam current from the ion source.

  6. Solid-state microwave annealing of ion-implanted 4H-SiC

    International Nuclear Information System (INIS)

    Sundaresan, Siddarth G.; Tian, Yong-lai; Ridgway, Mark C.; Mahadik, Nadeemullah A.; Qadri, Syed B.; Rao, Mulpuri V.

    2007-01-01

    Solid-state microwave annealing was performed at temperatures up to 2120 deg, C for 30 s on ion-implanted 4H-SiC in N 2 ambient. The surface roughness in the samples annealed without a surface cap at 1950 deg, C is 2.65 nm for 10 μm x 10 μm atomic force microscopy scans. The sheet resistances measured on Al + - and P + -implanted 4H-SiC, annealed by microwaves, are lower than the best conventional furnace annealing results reported in literature. X-ray diffraction spectra indicate alleviation of the lattice damage induced by the ion-implantation and also incorporation of most of the implanted species into substitutional lattice sites

  7. Controlled ion-beam transformation of silicon bipolar microwave power transistor's characteristics

    International Nuclear Information System (INIS)

    Solodukha, V.A.; Snitovskij, Yu.P.

    2015-01-01

    In this article, a method for changing the silicon bipolar microwave power transistor's characteristics in a direct and deliberate manner by modifying the chemical composition at the molybdenum - silicon boundary, the electro-physical properties of molybdenum - silicon contacts, and the electrophysical characteristics of transistor structure areas by the phosphorus ions irradiation of generated ohmic molybdenum - silicon contacts to the transistor emitters is proposed for the first time. The possibilities of this method are investigated and confirmed experimentally. (authors)

  8. Effect of high energy electrons on H{sup −} production and destruction in a high current DC negative ion source for cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Onai, M., E-mail: onai@ppl.appi.keio.ac.jp; Fujita, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Etoh, H.; Aoki, Y. [Sumitomo Heavy Industries, Ltd., Tokyo 141-6025 (Japan); Shibata, T. [High Energy Accelerator Research Organization (KEK), Ibaraki (Japan); Mattei, S.; Lettry, J. [CERN Rte de Meyrin, 1200 Geneva (Switzerland)

    2016-02-15

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H{sup −} production. The modelling results reasonably explains the dependence of the H{sup −} extraction current on the arc-discharge power in the experiments.

  9. Measurements of actinometry and ions energy in a microwave discharge

    International Nuclear Information System (INIS)

    Becerril, F.; Camps, E.; Villagran, M.; Muhl, S.

    1998-01-01

    In the present work it is showed the implementation of the plasma diagnostic technique through actinometry which allows to determine the absolute density of excited species. It is showed the range of the technique application, for the case of N 2 -H 2 mixtures plasmas used for the metals nitridation. The effects of magnetic field and the work pressure over ions energy were determined, using a Faraday cup type energy analyser. The results showed that in our device it is possible to vary such energy in a range between 10-45 eV, which amplify the range of applications perceptibly in comparison with another type of discharges. (Author)

  10. Analysis of influence of heat exchange conditions on the outer surface of the lithium-ion battery to electrolyte temperature under the conditions of high current loads

    Directory of Open Access Journals (Sweden)

    Krasnoshlykov Alexander

    2017-01-01

    Full Text Available Numerical analysis of thermal conditions of a lithium-ion battery using the software package ANSYS Electric and ANSYS Fluent has been carried out. Time dependence of the electrolyte temperature on the various heat exchange conditions on the outer surface has been obtained.

  11. High current induction linacs

    International Nuclear Information System (INIS)

    Barletta, W.; Faltens, A.; Henestroza, E.; Lee, E.

    1994-07-01

    Induction linacs are among the most powerful accelerators in existence. They have accelerated electron bunches of several kiloamperes, and are being investigated as drivers for heavy ion driven inertial confinement fusion (HIF), which requires peak beam currents of kiloamperes and average beam powers of some tens of megawatts. The requirement for waste transmutation with an 800 MeV proton or deuteron beam with an average current of 50 mA and an average power of 40 MW lies midway between the electron machines and the heavy ion machines in overall difficulty. Much of the technology and understanding of beam physics carries over from the previous machines to the new requirements. The induction linac allows use of a very large beam aperture, which may turn out to be crucial to reducing beam loss and machine activation from the beam halo. The major issues addressed here are transport of high intensity beams, availability of sources, efficiency of acceleration, and the state of the needed technology for the waste treatment application. Because of the transformer-like action of an induction core and the accompanying magnetizing current, induction linacs make the most economic sense and have the highest efficiencies with large beam currents. Based on present understanding of beam transport limits, induction core magnetizing current requirements, and pulse modulators, the efficiencies could be very high. The study of beam transport at high intensities has been the major activity of the HIF community. Beam transport and sources are limiting at low energies but are not significant constraints at the higher energies. As will be shown, the proton beams will be space-charge-dominated, for which the emittance has only a minor effect on the overall beam diameter but does determine the density falloff at the beam edge

  12. Microwave frequency sweep interferometer for plasma density measurements in ECR ion sources: Design and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, Giuseppe [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); University Mediterranea of Reggio Calabria, Reggio Calabria (Italy); Mascali, David; Neri, Lorenzo; Leonardi, Ornella; Celona, Luigi; Castro, Giuseppe; Agnello, Riccardo; Caruso, Antonio; Passarello, Santi; Longhitano, Alberto; Gammino, Santo [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Sorbello, Gino [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); University of Catania, Catania, Italy and INFN-LNS, Catania (Italy); Isernia, Tommaso [University Mediterranea of Reggio Calabria, Reggio Calabria (Italy)

    2016-02-15

    The Electron Cyclotron Resonance Ion Sources (ECRISs) development is strictly related to the availability of new diagnostic tools, as the existing ones are not adequate to such compact machines and to their plasma characteristics. Microwave interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for plasma density measurement in hostile environment. Interferometry in ECRISs is a challenging task mainly due to their compact size. The typical density of ECR plasmas is in the range 10{sup 11}–10{sup 13} cm{sup −3} and it needs a probing beam wavelength of the order of few centimetres, comparable to the chamber radius. The paper describes the design of a microwave interferometer developed at the LNS-INFN laboratories based on the so-called “frequency sweep” method to filter out the multipath contribution in the detected signals. The measurement technique and the preliminary results (calibration) obtained during the experimental tests will be presented.

  13. Microwave receivers for fast-ion detection in fusion plasmas

    International Nuclear Information System (INIS)

    Furtula, V.

    2012-02-01

    The main objectives of this thesis are to determine fundamental properties of a millimeter wave radiometer used to detect radiation associated with dynamics of fast ions and to investigate possibilities for improvements and new designs. The detection of fast ions is based on a principle called collective Thomson scattering (CTS). The Danish CTS group has been involved in fusion plasma experiments for more than 10 years and the future plans will most probably include the International Thermonuclear Experimental Reactor (ITER). Current CTS systems designed by the Danish group are specified for the frequency range from 100 to 110 GHz. In this thesis we follow the path of the radiation from a fusion plasma to the data acquisition unit. Firstly, the scattered radiation passes through the quasi-optical system. Quasi-optical elements required to be installed on the high field side (HFS) on the ITER are assessed. For the ITER HFS receiver we have designed and measured the quasi-optical components that form a transmission link between the plasma and the radio frequency (RF) electronics. This HFS receiver is required to resolve the near parallel velocity components created by the alpha particles. Secondly, the radiation will encounter the RF part. This part is not yet designed for ITER, but instead the solution is addressed to the CTS receiver installed at ASDEX Upgrade (AUG).We have put effort to thoroughly examine and evaluate the performance of the receiver components and the receiver as an assembled unit. We have measured and analyzed all the receiver components starting from the two notch filters to the fifty square-law detector diodes. The receiver sensitivity is calculated from the system measurements and compared with the expected sensitivity based on the individual component measurements. Besides the system considerations we have also studied improvements of two critical components of the receiver. The first component is the notch filter, which is needed to block

  14. Studying Heavy Ion Collisions Using Methods From Cosmic Microwave Background (CMB Analysis

    Directory of Open Access Journals (Sweden)

    Gaardhøje J. J.

    2014-04-01

    Full Text Available We present and discuss a framework for studying the morphology of high-multiplicity events from relativistic heavy ion collisions using methods commonly employed in the analysis of the photons from the Cosmic Microwave Background (CMB. The analysis is based on the decomposition of the distribution of the number density of (charged particles expressed in polar and azimuthal coordinates into a sum of spherical harmonic functions. We present an application of the method exploting relevant symmetries to the study of azimuthal correlations arizing from collective flow among charged particles produced in relativistic heavy ion collisions. We discuss perspectives for event-by- event analyses, which with increasing collision energy will eventually open entirely new dimensions in the study of ultrarelaticistic heavy ion reactions.

  15. Microwave Ion Source and Beam Injection for an Accelerator-driven Neutron Source

    International Nuclear Information System (INIS)

    Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt, B.A.; Regis, M.J.; Wallig, J.G.; Wells, R.

    2007-01-01

    An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomic fraction >90 percent was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D+ beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create ∼ 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. We observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared with PBGUNS simulations

  16. Microwave Ion Source and Beam Injection for an Accelerator-Driven Neutron Source

    International Nuclear Information System (INIS)

    Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt, B.A.; Regis, M.J.; Wallig, J.G.; Wells, R.

    2007-01-01

    An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm 2 and with atomic fraction > 90% was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D + beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create ∼ 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. They observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared with PBGUNS simulations

  17. Microwave frequency dependence of the properties of the ion beam extracted from a CAPRICE type ECRIS

    International Nuclear Information System (INIS)

    Maimone, F.; Tinschert, K.; Spaedtke, P.; Maeder, J.; Rossbach, J.; Lang, R.; Celona, L.

    2012-01-01

    In order to improve the quality of ion beams extracted from ECR ion sources it is mandatory to better understand the relations between the plasma conditions and the beam properties. The present investigations concentrate on the analysis of different beam properties under the influence of various applications of frequency tuning and of multiple frequency heating. The changes in the microwave frequency feeding the plasma affect the electromagnetic field distribution and the dimension and position of the ECR surface inside the plasma chamber. This in turn has an influence on the generation of the extracted ion beam in terms of intensity, shape and emittance. In order to analyze the corresponding effects, measurements have been performed with the CAPRICE-Type ECRIS installed at the ECR Injector Setup (EIS) of GSI. The experimental setup uses a microwave sweep generator which feeds a TWTA (Traveling Wave Tube Amplifier) covering a wide frequency range from 12.5 to 16.5 GHz. This arrangement provides a precise determination of the frequencies and of the reflection coefficient along with the beam properties and it confirms again how the frequency and the corresponding electromagnetic field feeding the plasma affects the ECRIS performances. A sequence of viewing targets positioned inside the beam line monitors the beam shape evolution. The paper is followed by the associated poster

  18. A Novel Microwave-Induced Plasma Ionization Source for Ion Mobility Spectrometry

    Science.gov (United States)

    Dai, Jianxiong; Zhao, Zhongjun; Liang, Gaoling; Duan, Yixiang

    2017-03-01

    This work demonstrates the application of a novel microwave induced plasma ionization (MIPI) source to ion mobility spectrometry (IMS). The MIPI source, called Surfatron, is composed of a copper cavity and a hollow quartz discharge tube. The ion mobility spectrum of synthetics air has a main peak with reduced mobility of 2.14 cm2V-1s-1 for positive ion mode and 2.29 cm2V-1s-1 for negative ion mode. The relative standard deviations (RSD) are 0.7% and 1.2% for positive and negative ion mode, respectively. The total ion current measured was more than 3.5 nA, which is much higher than that of the conventional 63Ni source. This indicates that a better signal-to-noise ratio (SNR) can be acquired from the MIPI source. The SNR was 110 in the analysis of 500 pptv methyl tert-butyl ether (MTBE), resulting in the limit of detection (SNR = 3) of 14 pptv. The linear range covers close to 2.5 orders of magnitude in the detection of triethylamine with a concentration range from 500 pptv to 80 ppbv. Finally, this new MIPI-IMS was used to detect some volatile organic compounds, which demonstrated that the MIPI-IMS has great potential in monitoring pollutants in air.

  19. Determination of nitrate in lettuce by ion chromatography after microwave water extraction

    Directory of Open Access Journals (Sweden)

    Humberto Brevilato Novaes

    2009-01-01

    Full Text Available Lettuce is worldwide known as the most important vegetable. In this context, most farmers are searching new techniques for best quality products including hydropony. However, nitrate is of great concern, since it has a negative impact on human metabolism. The main objective of the present work was to evaluate the nitrate content of lettuce produced by conventional and hydroponic systems. The determination was conducted by ion chromatography and a new method of extraction was tested using microwave oven digestion. The results indicated that nitrate level produced in the conventional system was lower than in the hydroponic system.

  20. Improvement of a microwave ECR plasma source for the plasma immersion ion implantation and deposition process

    International Nuclear Information System (INIS)

    Wu Hongchen; Zhang Huafang; Peng Liping; Jiang Yanli; Ma Guojia

    2004-01-01

    The Plasma Immersion Ion Implantation and Deposition (PIII and D) process has many advantages over the pure plasma immersion ion implantation or deposition. It can compensate for or eliminate the disadvantages of the shallow modification layer (for PIII) and increase the bond strength of the coating (of deposition). For this purpose, a new type of microwave plasma source used in the PIII and D process was developed, composed of a vacuum bend wave guide and a special magnetic circuit, so that the coupling window was protected from being deposited with a coating and bombarded by high-energy particles. So the life of the window is increased. To enhance the bonding between the coating and substrate a new biasing voltage is applied to the work piece so that the implantation and deposition (or hybrid process) can be completed in one vacuum cycle

  1. Electronic and ionic conductivity studies on microwave synthesized glasses containing transition metal ions

    Directory of Open Access Journals (Sweden)

    Basareddy Sujatha

    2017-01-01

    Full Text Available Glasses in the system xV2O5·20Li2O·(80 − x [0.6B2O3:0.4ZnO] (where 10 ≤ x ≤ 50 have been prepared by a simple microwave method. Microwave synthesis of materials offers advantages of efficient transformation of energy throughout the volume in an effectively short time. Conductivity in these glasses was controlled by the concentration of transition metal ion (TMI. The dc conductivity follows Arrhenius law and the activation energies determined by regression analysis varies with the content of V2O5 in a non-linear passion. This non-linearity is due to different conduction mechanisms operating in the investigated glasses. Impedance and electron paramagnetic resonance (EPR spectroscopic studies were performed to elucidate the nature of conduction mechanism. Cole–cole plots of the investigated glasses consist of (i single semicircle with a low frequency spur, (ii two depressed semicircles and (iii single semicircle without spur, which suggests the operation of two conduction mechanisms. EPR spectra reveal the existence of electronic conduction between aliovalent vanadium sites. Further, in highly modified (10V2O5 mol% glasses Li+ ion migration dominates.

  2. Compact high-current, subnanosecond electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shpak, V G; Shunajlov, S A; Ulmaskulov, M R; Yalandin, M I [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Electrophysics; Pegel, I V [Russian Academy of Sciences, Tomsk (Russian Federation). High-Current Electronics Inst.; Tarakanov, V P [Russian Academy of Sciences, Moscow (Russian Federation). High-Temperature Inst.

    1997-12-31

    A compact subnanosecond, high-current electron accelerator producing an annular electron beam of duration up to 300 - 400 ps, energy about 250 keV, and current up to 1 kA has been developed to study transient processes in pulsed power microwave devices. The measuring and recording techniques used to experimentally investigate the dynamics of the beam current pulse and the transformation of the electron energy during the transportation of the beam in a longitudinal magnetic field are described. The experimental data obtained are compared with the predictions of a numerical simulation. (author). 6 figs., 5 refs.

  3. Microwave Derived Facile Approach to Sn/Graphene Composite Anodes for, Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Beck, Faith R.; Epur, Rigved; Hong, Daeho; Manivannan, Ayyakkannu; Kumta, Prashant N.

    2014-01-01

    Graphical abstract: Tin particles embedded in graphene (G) sheet have been synthesized by microwave reduction of tin halide (SnCl 2 ) and graphite oxide (GO) followed by annealing in argon. The microwave reaction resulted in the formation of tin oxide embedded in graphene sheets. Annealing in argon at elevated temperatures initiated carbothermal reduction culminating in the formation of tin decorated graphene sheet composites that were employed as anodes for lithium-ion batteries. X-ray diffraction analysis of the final composite showed the presence of crystalline tin combined with a very small diffraction peak corresponding to (002) plane of graphite. Scanning electron microscopy (SEM) revealed decorated graphene layers with tin droplets. X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of graphene and graphene oxide in the composite. Electrochemical cycling response indicated that the tin/graphene composite exhibited initial discharge capacities varying from 790 mAh/g to 850 mAh/g depending on the composition, while a stable reversible capacity of ∼500 mAh/g was achieved for optimized compositions when cycled at a current density of ∼100 mA/g in the voltage window of 0.02 to 1.2 V vs. Li + /Li. Carbon coating of the Sn/G composite ultimately achieved by decomposition of dextrose using microwave heating significantly improved the electrochemical cycling stability. - Highlights: • Tin embedded graphene sheets have been synthesized by microwave reduction. • Tin oxide and graphene formed was carbothermally reduced to Sn/graphene. • XPS confirmed presence of graphene and graphene oxide in the composite. • Electrochemical response indicated capacities in 790 mAh/g to 850 mAh/g range. • Carbon coated composite yielded stable reversible capacity ∼500 mAh/g. - Abstract: Tin particles embedded in graphene (G) sheets have been synthesized by microwave reduction of tin halide (SnCl 2 .2H 2 O) and graphite oxide (GO) followed by annealing in argon

  4. Microwave plasma ion sources for selected ion flow tube mass spectrometry: Optimizing their performance and detection limits for trace gas analysis

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Dryahina, Kseniya; Smith, D.

    2007-01-01

    Roč. 267, 1-3 (2007), s. 117-124 ISSN 1387-3806 R&D Projects: GA ČR GA202/06/0776 Institutional research plan: CEZ:AV0Z40400503 Keywords : microwave plasma ion source * selected ion flow tube mass spectrometry * SIFT-MS * breath analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.411, year: 2007

  5. CW/Pulsed H- ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Science.gov (United States)

    Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, A. L.; Zhang, J. F.; Zhao, J.; Guo, Z. Y.; Chen, J. E.

    2015-04-01

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H- beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H- source able to produce very intense H- beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H- ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H- ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H- beam with rms emittance about 0.16 π.mm.mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H- ion beam at 35 keV with rms emittance about 0.2 π.mm.mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H- source body is ϕ116 mm × 124 mm, and the entire H- source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  6. Study of the ion density of a radio-frequency plasma using electrostatic probes and focussed microwave interferometers

    International Nuclear Information System (INIS)

    Nguyen Cao, L.; Gagne, R.R.J.

    1976-01-01

    In order to verify experimentally and compare recent ion theories for cylindrical electrostatic probes, the ion density in a radio-frequency plasma was evaluated from V-I curves by means of six different theories. At low pressures, the theories of Bernstein and Rabinowitz, of Lam and Laframboise, give values of density which differ respectively by 20, 25 and 30% compared with the values obtained using a 10GHz focussed microwave interferometer. At the continuum limit, The Schulz and Brown's, and Su and Kiel's theories give density values which disagree respectively by 55 and 20%, compared with the values obtained by microwaves. For pressures varying from 0.05 to 3mmHg, the decrease of ion current, as predicted theorically by Waymouth, was observed. The density perturbation near the probe was found to be a dominant factor affecting the precision of density measurements, for pressures up to 2mmHg at least for our experimental conditions [fr

  7. High current vacuum closing switch

    International Nuclear Information System (INIS)

    Dolgachev, G.I.; Maslennikov, D.D.; Romanov, A.S.; Ushakov, A.G.

    2005-01-01

    The paper proposes a powerful pulsed closing vacuum switch for high current commutation consisting of series of the vacuum diodes with near 1 mm gaps having closing time determined by the gaps shortening with the near-electrode plasmas [ru

  8. Three-dimensional thermal simulations of thin solid carbon foils for charge stripping of high current uranium ion beams at a proposed new heavy-ion linac at GSI

    Directory of Open Access Journals (Sweden)

    N. A. Tahir

    2014-04-01

    Full Text Available This paper presents an extensive numerical study of heating of thin solid carbon foils by 1.4  MeV/u uranium ion beams to explore the possibility of using such a target as a charge stripper at the proposed new Gesellschaft für Schwerionenforschung high energy heavy–ion linac. These simulations have been carried out using a sophisticated 3D computer code that accounts for physical phenomena that are important in this problem. A variety of beam and target parameters have been considered. The results suggest that within the considered parameter range, the target will be severely damaged by the beam. Thus, a carbon foil stripper does not seem to be a reliable option for the future Gesellschaft für Schwerionenforschung high energy heavy–ion linac, in particular, at FAIR design beam intensities.

  9. Sideband-cooling of trapped ytterbium-ions in the microwave regime; Seitenbandkuehlung von gespeicherten Ytterbium-Ionen im Mikrowellenregime

    Energy Technology Data Exchange (ETDEWEB)

    Scharfenberger, Benedikt J.

    2012-12-14

    Trapped ions in a Paul trap are at present one of the most promising candidates for Quantum Information Processing (QIP). The technique that is used for this purpose in this experiment was introduced in 2001 by F. Mintert and Ch. Wunderlich. The core of this method is the use of atomic transitions in the radio- or microwave region, while a magnetic field gradient along the trap axis (where the ion chain is situated) lifts the degeneracy of the transition frequencies, such that the ions can be distinguished in frequency space; it also serves for the coupling of internal and external degrees of freedom of the ion chain. This method is called MAGIC (MAgnetic Gradient Induced Coupling). The performance of the measurements required that the apparatus of the experiment, which consists of laser sources, lambdameter, vacuum- and microwave system as well as imaging- and detection-units, had to be assembled and tested, which was an important prerequisite for the successful performance of the here described experiments. For the experiments it is advantageous to prepare the ions in an energetic state close to the motional ground state, which contributes to a reduction of the dephasing of the system while manipulating it with microwaves. By using the sideband-cooling technique to the sub-Doppler regime it is taken advantage of the fact, that ions in a linear trap are in good approximation situated in a harmonic oscillator potential and can therefore only populate discrete vibrational energy levels, whose frequency difference is given by the axial trap frequency {omega}{sub z}. If the system is excited by a microwave, which frequency is detuned from resonance to lower energies by a vibrational quantum, the ion looses one such phonon within each cooling-cycle. When this cycle is driven several times, the average phonon number and thus the temperature of the ion can be reduced efficiently and the ion can be initialized in a state close to the motional ground state. As sideband

  10. Solvothermal synthesis of mesoporous magnetite nanoparticles for Cr(IV) ions uptake and microwave absorption

    KAUST Repository

    Shen, Peng; Zhang, Haitao; Zhang, Suojiang; Yuan, Pei; Yang, Yang; Zhang, Qiang; Zhang, Xixiang

    2016-01-01

    Abstract: Colloidal mesoporous magnetite nanoparticles with tunable porosity were realized by a simple and scalable solvothermal route with the aid of AOT as ligands. AOT was used to induce the anisotropic crystal growth of smaller nanocrystals and restrain their tight aggregation so as to form more mesoscale pores. Morphologies and microstructures investigation by SEM and TEM revealed that the bigger nanoparticles were composed of smaller nanocrystals with an average size of 18 nm. A possible formation mechanism was proposed for the mesoporous nanoparticles. Study of nitrogen adsorption–desorption isotherm revealed that the Brunauer–Emmett–Teller (BET) specific surface area of mesoporous nanoparticles is up to 209 m2/g, resulting from the slit-shaped pores created by the aggregation of polyhedral nanocrystals. Magnetic properties study indicated that the as-prepared nanoparticles are superparamagnetic at room temperature. Optimized mesoporous magnetite nanoparticles exhibit a maximum Cr(VI) ion sorption capacity of 12.9 mmol/g, and its absorption behavior followed a Freundlich model. Microwave absorption study indicated that porous nanoparticles own higher permeability values than that of solid nanoparticles, leading to a higher dielectric loss in the frequency range of 2–18 GHz. Graphical Abstract: [Figure not available: see fulltext.] © 2016, Springer Science+Business Media Dordrecht.

  11. Microwave process employed to study the immobilization feasibility of spent ion exchange resins in polymeric matrices

    Energy Technology Data Exchange (ETDEWEB)

    Caratin, Reinaldo L.; Araujo, Sumair G. de; Landini, Liliane; Neves, Sabrina C.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], E-mail: rcaratin@ipen.br, E-mail: sgaraujo@ipen.br, E-mail: llandini@ipen.br, E-mail: scneves@ipen.br, E-mail: ablugao@ipen.br

    2007-07-01

    Nuclear activities generate radioactive wastes in several physical states, radioactive levels and kinds of radioactive emission. Hence, a lot of techniques have been developed and optimized to do the immobilization of these materials, according to local and international regulations to protect human being and environment. Another great concern is the indiscriminate disposal of used polymeric materials (such as plastic and rubber) or production leftovers in landfills, which remain for many years before they are naturally decomposed. In this work, it was studied the possibility of carrying out the immobilization of spent ion exchange resins (contaminated with ionising radiation), by using polymeric matrices of bitumen and rubber (as solidification materials for the storage of low level radioactive waste). The samples were mixed at different percentages and were heated in a microwave device (2,450 MHz) at IPEN/CNEN-SP, varying the irradiation time and power. The objective of the immobilization is converting the wastes into forms that are leach resistant and physically and chemically stable for disposal. Characterizations of these materials have been performed according to ABNT-NBR standards. The results indicated the previous idea of the necessary minimum temperature to keep the matrix for future embedding of radioactive waste, in solid state. (author)

  12. Solvothermal synthesis of mesoporous magnetite nanoparticles for Cr(IV) ions uptake and microwave absorption

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Peng; Zhang, Haitao, E-mail: htzhang@ipe.ac.cn; Zhang, Suojiang, E-mail: sjzhang@ipe.ac.cn; Yuan, Pei [Chinese Academy of Sciences, Beijing Key Laboratory of Ionic Liquids Clean Process Institute of Process Engineering, Key Laboratory of Green Process and Engineering, Institute of Process Engineering (China); Yang, Yang [China Building Materials Academy, State Key Laboratory of Green Building Materials (China); Zhang, Qiang; Zhang, Xixiang [King Abdullah University of Science and Technology, Physical Science and Engineering (Saudi Arabia)

    2016-05-15

    Colloidal mesoporous magnetite nanoparticles with tunable porosity were realized by a simple and scalable solvothermal route with the aid of AOT as ligands. AOT was used to induce the anisotropic crystal growth of smaller nanocrystals and restrain their tight aggregation so as to form more mesoscale pores. Morphologies and microstructures investigation by SEM and TEM revealed that the bigger nanoparticles were composed of smaller nanocrystals with an average size of 18 nm. A possible formation mechanism was proposed for the mesoporous nanoparticles. Study of nitrogen adsorption–desorption isotherm revealed that the Brunauer–Emmett–Teller (BET) specific surface area of mesoporous nanoparticles is up to 209 m{sup 2}/g, resulting from the slit-shaped pores created by the aggregation of polyhedral nanocrystals. Magnetic properties study indicated that the as-prepared nanoparticles are superparamagnetic at room temperature. Optimized mesoporous magnetite nanoparticles exhibit a maximum Cr(VI) ion sorption capacity of 12.9 mmol/g, and its absorption behavior followed a Freundlich model. Microwave absorption study indicated that porous nanoparticles own higher permeability values than that of solid nanoparticles, leading to a higher dielectric loss in the frequency range of 2–18 GHz.Graphical Abstract.

  13. Solvothermal synthesis of mesoporous magnetite nanoparticles for Cr(IV) ions uptake and microwave absorption

    KAUST Repository

    Shen, Peng

    2016-05-12

    Abstract: Colloidal mesoporous magnetite nanoparticles with tunable porosity were realized by a simple and scalable solvothermal route with the aid of AOT as ligands. AOT was used to induce the anisotropic crystal growth of smaller nanocrystals and restrain their tight aggregation so as to form more mesoscale pores. Morphologies and microstructures investigation by SEM and TEM revealed that the bigger nanoparticles were composed of smaller nanocrystals with an average size of 18 nm. A possible formation mechanism was proposed for the mesoporous nanoparticles. Study of nitrogen adsorption–desorption isotherm revealed that the Brunauer–Emmett–Teller (BET) specific surface area of mesoporous nanoparticles is up to 209 m2/g, resulting from the slit-shaped pores created by the aggregation of polyhedral nanocrystals. Magnetic properties study indicated that the as-prepared nanoparticles are superparamagnetic at room temperature. Optimized mesoporous magnetite nanoparticles exhibit a maximum Cr(VI) ion sorption capacity of 12.9 mmol/g, and its absorption behavior followed a Freundlich model. Microwave absorption study indicated that porous nanoparticles own higher permeability values than that of solid nanoparticles, leading to a higher dielectric loss in the frequency range of 2–18 GHz. Graphical Abstract: [Figure not available: see fulltext.] © 2016, Springer Science+Business Media Dordrecht.

  14. High current plasma electron emitter

    International Nuclear Information System (INIS)

    Fiksel, G.; Almagri, A.F.; Craig, D.

    1995-07-01

    A high current plasma electron emitter based on a miniature plasma source has been developed. The emitting plasma is created by a pulsed high current gas discharge. The electron emission current is 1 kA at 300 V at the pulse duration of 10 ms. The prototype injector described in this paper will be used for a 20 kA electrostatic current injection experiment in the Madison Symmetric Torus (MST) reversed-field pinch. The source will be replicated in order to attain this total current requirement. The source has a simple design and has proven very reliable in operation. A high emission current, small size (3.7 cm in diameter), and low impurity generation make the source suitable for a variety of fusion and technological applications

  15. High PRF high current switch

    Science.gov (United States)

    Moran, Stuart L.; Hutcherson, R. Kenneth

    1990-03-27

    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  16. Microwave and conventional preparation of Zinc borate glass: Eu3+ ion as luminescent probe

    International Nuclear Information System (INIS)

    Mandal, Ashis K.; Balaji, S.; Sen, Ranjan

    2014-01-01

    Highlights: • IR transparent Zinc borate glass is prepared using microwave heating. • Glass transition temperature of microwave melted glass is found higher than that of glass prepared in conventional melting. • Low OH concentration in glass can be prepared in microwave heating. • We report higher reduction of Eu 3+ to Eu 2+ in microwave processing of Zinc borate glass. - Abstract: Transparent Zinc borate glass is melted using microwave energy as an alternative heating route to conventional resistive heating. A comparative study of the properties of the glasses prepared by both the methods is conducted by adopting X-ray diffraction (XRD), Differential scanning calorimetry (DSC), UV–VIS–NIR spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Refractive Indices (RI). Amorphous nature of samples is confirmed by X-ray diffraction study. Glass transition temperature (T g ) of microwave melted glass is found ∼7–9 °C higher than that of glass prepared in conventional melting. OH content is found less than 250 ppm in microwave melted glass whereas it is above 330 ppm in conventional melted glasses. Photoluminescence study of Eu 2 O 3 doped glass prepared in microwave heating indicates higher reduction of Eu 3+ → Eu 2+ than the glass melted in conventional route. Thus, microwave processing can be an alternative energy efficient, time saving, environmental friendly glass preparation method

  17. Development of the integrated control system for the microwave ion source of the PEFP 100-MeV proton accelerator

    Science.gov (United States)

    Song, Young-Gi; Seol, Kyung-Tae; Jang, Ji-Ho; Kwon, Hyeok-Jung; Cho, Yong-Sub

    2012-07-01

    The Proton Engineering Frontier Project (PEFP) 20-MeV proton linear accelerator is currently operating at the Korea Atomic Energy Research Institute (KAERI). The ion source of the 100-MeV proton linac needs at least a 100-hour operation time. To meet the goal, we have developed a microwave ion source that uses no filament. For the ion source, a remote control system has been developed by using experimental physics and the industrial control system (EPICS) software framework. The control system consists of a versa module europa (VME) and EPICS-based embedded applications running on a VxWorks real-time operating system. The main purpose of the control system is to control and monitor the operational variables of the components remotely and to protect operators from radiation exposure and the components from critical problems during beam extraction. We successfully performed the operation test of the control system to confirm the degree of safety during the hardware performance.

  18. Automated system for efficient microwave power coupling in an S-band ECR ion source driven under different operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Muguira, L., E-mail: lmuguira@essbilbao.org [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Portilla, J. [University of Basque Country (UPV/EHU), Department of Electricity and Electronics, Science and Technology Faculty, 48940 Leioa (Bizkaia) (Spain); Gonzalez, P.J.; Garmendia, N.; Feuchtwanger, J. [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Etxebarria, V. [University of Basque Country (UPV/EHU), Department of Electricity and Electronics, Science and Technology Faculty, 48940 Leioa (Bizkaia) (Spain); Eguiraun, M.; Arredondo, I.; Miracoli, R.; Belver, D. [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain)

    2014-03-21

    This article presents an automated system for optimizing the microwave power coupling to the plasma generated in a proton/deuteron Electron Cyclotron Resonance (ECR) source, based on a specific model of a rectangular waveguide triple-stub tuner and the integrated measurement and control electronics, helping to get stable plasma states. The control and improvement of the RF power absorption into the plasma is a complex process, essential for the ion source development and optimization under different operating conditions. A model and a matching algorithm for the triple-stub tuner have been developed and, besides, different methods to accurately measure the power transfer in a waveguide RF system have been studied and deployed in the ESS-Bilbao ion source system. The different parts have been integrated through a controller, which allows to run an automatic plasma matching system in closed loop. The behavior of the system implemented for low and high power regimes has been tested under different conditions: with several load impedances, with plasma inside the chamber, in continuous wave and pulsed wave operation modes, demonstrating power absorption typically over 90% in all the ion source configurations. The developed system allows to achieve significant improvement in the ECR ion source power absorption efficiency, both in continuous and pulsed mode. The automatic tuning unit enhances the system operation finding an optimum solution much faster than manually, also behaving as an adaptive system able to respond in few pulses to ion source configuration changes to maintain the power coupling as high as possible. - Highlights: • An automated system optimizing plasma and microwave power interaction is presented. • A model and a matching algorithm for the triple-stub tuner have been developed. • Different methods to measure the power transfer have been studied and deployed. • The system works for low or high power regimes under different ion source conditions.

  19. Automated system for efficient microwave power coupling in an S-band ECR ion source driven under different operating conditions

    International Nuclear Information System (INIS)

    Muguira, L.; Portilla, J.; Gonzalez, P.J.; Garmendia, N.; Feuchtwanger, J.; Etxebarria, V.; Eguiraun, M.; Arredondo, I.; Miracoli, R.; Belver, D.

    2014-01-01

    This article presents an automated system for optimizing the microwave power coupling to the plasma generated in a proton/deuteron Electron Cyclotron Resonance (ECR) source, based on a specific model of a rectangular waveguide triple-stub tuner and the integrated measurement and control electronics, helping to get stable plasma states. The control and improvement of the RF power absorption into the plasma is a complex process, essential for the ion source development and optimization under different operating conditions. A model and a matching algorithm for the triple-stub tuner have been developed and, besides, different methods to accurately measure the power transfer in a waveguide RF system have been studied and deployed in the ESS-Bilbao ion source system. The different parts have been integrated through a controller, which allows to run an automatic plasma matching system in closed loop. The behavior of the system implemented for low and high power regimes has been tested under different conditions: with several load impedances, with plasma inside the chamber, in continuous wave and pulsed wave operation modes, demonstrating power absorption typically over 90% in all the ion source configurations. The developed system allows to achieve significant improvement in the ECR ion source power absorption efficiency, both in continuous and pulsed mode. The automatic tuning unit enhances the system operation finding an optimum solution much faster than manually, also behaving as an adaptive system able to respond in few pulses to ion source configuration changes to maintain the power coupling as high as possible. - Highlights: • An automated system optimizing plasma and microwave power interaction is presented. • A model and a matching algorithm for the triple-stub tuner have been developed. • Different methods to measure the power transfer have been studied and deployed. • The system works for low or high power regimes under different ion source conditions.

  20. High current capacity electrical connector

    International Nuclear Information System (INIS)

    Bettis, E.S.; Watts, H.L.

    1976-01-01

    An electrical connector is provided for coupling high current capacity electrical conductors such as copper busses or the like. The connector is arranged in a ''sandwiched'' configuration in which a conductor plate contacts the busses along major surfaces clamped between two stainless steel backing plates. The conductor plate is provided with contact buttons in a spaced array such that the caps of the buttons extend above the conductor plate surface to contact the busses. When clamping bolts provided through openings in the sandwiched arrangement are tightened, Belleville springs provided under the rim of each button cap are compressed and resiliently force the caps into contact with the busses' contacting surfaces to maintain a predetermined electrical contact area provided by the button cap tops. The contact area does not change with changing thermal or mechanical stresses applied to the coupled conductors

  1. Achromatic beam transport of High Current Injector

    International Nuclear Information System (INIS)

    Kumar, Sarvesh; Mandal, A.

    2016-01-01

    The high current injector (HCI) provides intense ion beams of high charge state using a high temperature superconducting ECR ion source. The ion beam is accelerated upto a final energy of 1.8 MeV/u due to an electrostatic potential, a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The ion beam has to be transported to superconducting LINAC which is around 50 m away from DTL. This section is termed as high energy beam transport section (HEBT) and is used to match the beam both in transverse and longitudinal phase space to the entrance of LINAC. The HEBT section is made up of four 90 deg. achromatic bends and interconnecting magnetic quadrupole triplets. Two RF bunchers have been used for longitudinal phase matching to the LINAC. The ion optical design of HEBT section has been simulated using different beam dynamics codes like TRACEWIN, GICOSY and TRACE 3D. The field computation code OPERA 3D has been utilized for hardware design of all the magnets. All the dipole and quadrupole magnets have been field mapped and their test results such as edge angles measurements, homogeneity and harmonic analysis etc. are reported. The whole design of HEBT section has been performed such that the most of the beam optical components share same hardware design and there is ample space for beam diagnostics as per geometry of the building. Many combination of achromatic bends have been simulated to transport the beam in HEBT section but finally the four 90 deg. achromatic bend configuration is found to be the best satisfying all the geometrical constraints with simplified beam tuning process in real time

  2. High current transistor pulse generator

    International Nuclear Information System (INIS)

    Nesterov, V.; Cassel, R.

    1991-05-01

    A solid state pulse generator capable of delivering high current trapezoidally shaped pulses into an inductive load has been developed at SLAC. Energy stored in the capacitor bank of the pulse generator is switched to the load through a pair of Darlington transistors. A combination of diodes and Darlington transistors is used to obtain trapezoidal or triangular shaped current pulses into an inductive load and to recover the remaining energy in the same capacitor bank without reversing capacitor voltage. The transistors work in the switch mode, and the power losses are low. The rack mounted pulse generators presently used at SLAC contain a 660 microfarad storage capacitor bank and can deliver 400 amps at 800 volts into inductive loads up to 3 mH. The pulse generators are used in several different power systems, including pulse to pulse bipolar power supplies and in application with current pulses distributed into different inductive loads. The current amplitude and discharge time are controlled by the central computer system through a specially developed multichannel controller. Several years of operation with the pulse generators have proven their consistent performance and reliability. 8 figs

  3. High current superconductors for DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzone, Pierluigi, E-mail: pierluigi.bruzzone@psi.ch [Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom – Confédération Suisse, CH-5232 Villigen PSI (Switzerland); Sedlak, Kamil; Stepanov, Boris [Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom – Confédération Suisse, CH-5232 Villigen PSI (Switzerland)

    2013-10-15

    Highlights: ► Definition of requirement for TF coil based on the input of system code. ► A TF coil and conductor design for the European DEMO project. ► Use of React and Wind method opposite to Wind and React with related advantages. ► Hybridization of winding pack, Nb/Nb{sub 3}Sn, by graded layer winding. -- Abstract: In the assumption that DEMO will be an inductively driven tokamak, the number of load cycles will be in the range of several hundred thousands. The requirements for a new generation of Nb{sub 3}Sn based high current conductors for DEMO are drafted starting from the output of system code PROCESS. The key objectives include the stability of the DC performance over the lifetime of the machine and the effective use of the Nb{sub 3}Sn strand properties, for cost and reliability reasons. A preliminary layout of the winding pack and conductors for the toroidal field magnets is presented. To suppress the mechanism of reversible and irreversible degradation, i.e. to preserve in the cabled conductor the high critical current density of the strand, the thermal strain must be insignificant and no space for micro-bending under transverse load must be left in the strand bundle. The “react-and-wind” method is preferred here, with a graded, layer wound magnet, containing both Nb{sub 3}Sn and NbTi layers. The implications of the conductor choice on the coil design and technology are highlighted. A roadmap is sketched for the development of a full size prototype conductor sample and demonstration of the key technologies.

  4. Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source

    International Nuclear Information System (INIS)

    Kurisu, Yosuke; Kiriyama, Ryutaro; Takenaka, Tomoya; Nozaki, Dai; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2012-01-01

    We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I FC by the mobile plate tuner. The I FC is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I FC and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasma density contributes largely to the variation of the I FC when we change the position of the mobile plate tuner.

  5. Lithium-ions diffusion kinetic in LiFePO4/carbon nanoparticles synthesized by microwave plasma chemical vapor deposition for lithium-ion batteries

    Science.gov (United States)

    Gao, Chao; Zhou, Jian; Liu, Guizhen; Wang, Lin

    2018-03-01

    Olivine structure LiFePO4/carbon nanoparticles are synthesized successfully using a microwave plasma chemical vapor deposition (MPCVD) method. Microwave is an effective method to synthesize nanomaterials, the LiFePO4/carbon nanoparticles with high crystallinity can shorten diffusion routes for ionic transfer and electron tunneling. Meanwhile, a high quality, complete and homogenous carbon layer with appropriate thickness coating on the surface of LiFePO4 particles during in situ chemical vapor deposition process, which can ensure that electrons are able to transfer fast enough from all sides. Electrochemical impedance spectroscopy (EIS) is carried out to collect information about the kinetic behavior of lithium diffusion in LiFePO4/carbon nanoparticles during the charging and discharging processes. The chemical diffusion coefficients of lithium ions, DLi, are calculated in the range of 10-15-10-9 cm2s-1. Nanoscale LiFePO4/carbon particles show the longer regions of the faster solid-solution diffusion, and corresponding to the narrower region of the slower two-phase diffusion during the insertion/exaction of lithium ions. The CV and galvanostatic charge-discharge measurements show that the LiFePO4/carbon nanoparticles perform an excellent electrochemical performance, especially the high rate capacity and cycle life.

  6. A study of the ion-molecule reaction in a microwave plasma of propylene

    International Nuclear Information System (INIS)

    Carmi, U.

    1980-07-01

    Microwave plasma of propylene and of argon-propylene mixture were sampled by a quadrupole mass-spectrometer. The composition of the plasma was investigated as a function of external parameters such as pressure, initial concentration of gases, microwave power and sampling position. Three main paths were determined for the pyrolysis and polymerization of propylene, that constitute the rate determining step. Rate constants were determined for the various reactions between propylene and the intermediates. An overall rate constant for the disappearance of propylene was determined. This constant was found to be dependent on the initial gas concentration and on plasma pressure

  7. High current beam transport experiments at GSI

    International Nuclear Information System (INIS)

    Klabunde, J.; Schonlein, A.; Spadtke, P.

    1985-01-01

    The status of the high current ion beam transport experiment is reported. 190 keV Ar 1+ ions were injected into six periods of a magnetic quadrupole channel. Since the pulse length is > 0.5 ms partial space charge neutralization occurs. In our experiments, the behavior of unneutralized and partially space charge compensated beams is compared. With an unneutralized beam, emittance growth has been measured for high intensities even in case of the zero-current phase advance sigma 0 0 . This initial emittance growth at high tune depression we attribute to the homogenization effect of the space charge density. An analytical formula based on this assumption describes the emittance growth very well. Furthermore the predicted envelope instabilities for sigma 0 > 90 0 were observed even after 6 periods. In agreement with the theory, unstable beam transport was also experimentally found if a beam with different emittances in the two transverse phase planes was injected into the transport channel. Although the space charge force is reduced for a partially neutralized beam a deterioration of the beam quality was measured in a certain range of beam parameters. Only in the range where an unneutralized beam shows the initial emittance growth, the partial neutralization reduces this effect, otherwise the partially neutralized beam is more unstable

  8. High current polarized electron source

    Science.gov (United States)

    Suleiman, R.; Adderley, P.; Grames, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.

    2018-05-01

    Jefferson Lab operates two DC high voltage GaAs photoguns with compact inverted insulators. One photogun provides the polarized electron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) up to 200 µA. The other gun is used for high average current photocathode lifetime studies at a dedicated test facility up to 4 mA of polarized beam and 10 mA of un-polarized beam. GaAs-based photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed facilities that must operate in excess of tens of mA of polarized average current. This contribution describes techniques to maintain good vacuum while delivering high beam currents, and techniques that minimize damage due to ion bombardment, the dominant mechanism that reduces photocathode yield. Advantages of higher DC voltage include reduced space-charge emittance growth and the potential for better photocathode lifetime. Highlights of R&D to improve the performance of polarized electron sources and prolong the lifetime of strained-superlattice GaAs are presented.

  9. Theoretical analysis of the multiple resonances for many-level spin systems. The four-level spin system of s electron ions subjected to strong microwave fields

    International Nuclear Information System (INIS)

    Popescu, F.F.; Marica, F.

    1994-01-01

    The analytic steady state solutions of master equation for the density matrix of a multilevel spin system in dilute paramagnetic crystals at high temperature, subjected to strong microwave fields, are discussed. These solutions enable to obtain the populations of the levels, and the microwave powers absorbed or emitted by the crystal, in the presence of one, two or more microwave fields. A detailed theoretical study of the maser effects for s electron ions with nuclear spin one-half is carried out. In the case of three frequency correlated strong fields, when 'the spectroscopic' bridge conditions are fulfilled, sensitive detections, or high efficient generations of microwaves of frequency higher than those of the pumping fields are predicted. (author) 16 figs., 16 refs

  10. Microwave exfoliated graphene oxide/TiO{sub 2} nanowire hybrid for high performance lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Ishtiaque Shuvo, Mohammad Arif; Rodriguez, Gerardo; Karim, Hasanul; Lin, Yirong [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States); Islam, Md Tariqul; Noveron, Juan C. [Department of Chemistry, University of Texas at El Paso, El Paso, Texas 79968 (United States); Ramabadran, Navaneet [Department of Chemical Engineering, University of California at Santa Barbara, California 93106 (United States)

    2015-09-28

    Lithium ion battery (LIB) is a key solution to the demand of ever-improving, high energy density, clean-alternative energy systems. In LIB, graphite is the most commonly used anode material; however, lithium-ion intercalation in graphite is limited, hindering the battery charge rate and capacity. To date, one of the approaches in LIB performance improvement is by using porous carbon (PC) to replace graphite as anode material. PC's pore structure facilitates ion transport and has been proven to be an excellent anode material candidate in high power density LIBs. In addition, to overcome the limited lithium-ion intercalation obstacle, nanostructured anode assembly has been extensively studied to increase the lithium-ion diffusion rate. Among these approaches, high specific surface area metal oxide nanowires connecting nanostructured carbon materials accumulation have shown promising results for enhanced lithium-ion intercalation. Herein, we demonstrate a hydrothermal approach of growing TiO{sub 2} nanowires (TON) on microwave exfoliated graphene oxide (MEGO) to further improve LIB performance over PC. This MEGO-TON hybrid not only uses the high surface area of MEGO but also increases the specific surface area for electrode–electrolyte interaction. Therefore, this new nanowire/MEGO hybrid anode material enhances both the specific capacity and charge–discharge rate. Scanning electron microscopy and X-ray diffraction were used for materials characterization. Battery analyzer was used for measuring the electrical performance of the battery. The testing results have shown that MEGO-TON hybrid provides up to 80% increment of specific capacity compared to PC anode.

  11. Experimental study of high current negative ion sources D{sup -} / H{sup -}. Analysis based on the simulation of the negative ion transport in the plasma source; Etude experimentale de sources a fort courant d`ions negatifs D{sup -} / H{sup -}. Analyse fondee sur la simulation du transport des ions dans le plasma de la source

    Energy Technology Data Exchange (ETDEWEB)

    Riz, D.

    1996-10-30

    In the frame of the development of a neutral beam injection system able to work the ITER tokamak (International Thermonuclear Experimental Reactor), two negative ion sources, Dragon and Kamaboko, have been installed on the MANTIS test bed in Cadarache, and studies in order to extract 20 mA/cm{sup 2} of D{sup -}. The two production modes of negative ions have been investigated: volume production; surface production after cesium injection in the discharge. Experiments have shown that cesium seeding is necessary in order to reach the requested performances for ITER. 20 mA/cm{sup 2} have been extracted from the Kamaboko source for an arc power density of 2.5 kW/liter. Simultaneously, a code called NIETZSCHE has been developed to simulate the negative ions transport in the source plasma, from their birth place to the extraction holes. The ion trajectory is calculated by numerically solving the 3D motion equation, while the atomic processes of destruction, of elastic collisions H{sup -}/H{sup +} and of charge exchange H{sup -}/H{sup 0} are handled at each time step by a Monte Carlo procedure. The code allows to obtain the extraction probability of a negative ion produced at a given location. The calculations performed with NIETZSCHE have allowed to explain several phenomena observed on negative ion sources, such as the isotopic effect H{sup -}/D{sup -} and the influence of the polarisation of the plasma grid and of the magnetic filter on the negative ions current. The code has also shown that, in the type of sources contemplated for ITER, working with large arc power densities (> 1 kW/liter), only negative ions produced in volume at a distance lower that 2 cm from the plasma grid and those produced at the grid surface have a chance of being extracted. (author). 122 refs.

  12. Comparison between off-resonance and electron Bernstein waves heating regime in a microwave discharge ion source

    Energy Technology Data Exchange (ETDEWEB)

    Castro, G.; Di Giugno, R.; Miracoli, R. [INFN- Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Universita degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S. Sofia 64, 95123 Catania (Italy); Mascali, D. [INFN- Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Romano, F. P. [INFN- Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CNR-IBAM Via Biblioteca 4, 95124 Catania (Italy); Celona, L.; Gammino, S.; Lanaia, D.; Ciavola, G. [INFN- Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Serafino, T. [CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Di Bartolo, F. [Universita di Messina, Ctr. da Papardo-Sperone, 98100 Messina (Italy); Gambino, N. [INFN- Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Universita degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S. Sofia 64, 95123 Catania (Italy); IET-Institute of Energy Technology, LEC-Laboratory for Energy Conversion, ETH Zurich, Sonneggstrasse 3, CH-8092 Zurich (Switzerland)

    2012-02-15

    A microwave discharge ion source (MDIS) operating at the Laboratori Nazionali del Sud of INFN, Catania has been used to compare the traditional electron cyclotron resonance (ECR) heating with an innovative mechanisms of plasma ignition based on the electrostatic Bernstein waves (EBW). EBW are obtained via the inner plasma electromagnetic-to-electrostatic wave conversion and they are absorbed by the plasma at cyclotron resonance harmonics. The heating of plasma by means of EBW at particular frequencies enabled us to reach densities much larger than the cutoff ones. Evidences of EBW generation and absorption together with X-ray emissions due to high energy electrons will be shown. A characterization of the discharge heating process in MDISs as a generalization of the ECR heating mechanism by means of ray tracing will be shown in order to highlight the fundamental physical differences between ECR and EBW heating.

  13. Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jiali; Yu, Xinhai, E-mail: yxhh@ecust.edu.cn; Tu, Shan-Tung; Wang, Zhengdong [Key Laboratory of Pressure Systems and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai (China); Wang, Zhenyu [Integrated Micro & Nano System Engineering Center, School of Software and Microelectronics at Wuxi, Peking University (China)

    2016-04-15

    The effects of the gas pressure (p{sub g}), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d{sub h} = 1000 μm) driven at constant voltage loading on the drive electrode (V{sub rf}) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p{sub g} increased, the maximum electron (n{sub e}) or ion density (n{sub Ar+}) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ{sub SEE-e}). The peak n{sub e} and n{sub Ar+} were not a monotonic function of p{sub g}, resulting from the two conflicting effects of p{sub g} on n{sub e} and n{sub Ar+}. The impact of ions on the electrode was enhanced when p{sub g} increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p{sub g}. The effects of t on the peaks and distributions of n{sub e} and n{sub Ar+} were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p{sub g} of 800 Pa and V{sub rf} of 180 V. The Au vapor addition increased the peaks of n{sub e} and n{sub Ar+}, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

  14. Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

    International Nuclear Information System (INIS)

    Tang, Jiali; Yu, Xinhai; Tu, Shan-Tung; Wang, Zhengdong; Wang, Zhenyu

    2016-01-01

    The effects of the gas pressure (p_g), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d_h = 1000 μm) driven at constant voltage loading on the drive electrode (V_r_f) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p_g increased, the maximum electron (n_e) or ion density (n_A_r_+) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ_S_E_E_-_e). The peak n_e and n_A_r_+ were not a monotonic function of p_g, resulting from the two conflicting effects of p_g on n_e and n_A_r_+. The impact of ions on the electrode was enhanced when p_g increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p_g. The effects of t on the peaks and distributions of n_e and n_A_r_+ were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p_g of 800 Pa and V_r_f of 180 V. The Au vapor addition increased the peaks of n_e and n_A_r_+, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

  15. Microwave-assisted convenient syntheses of 2-indolizine derivatives from Morita-Baylis-Hillman adducts: new in silico potential ion channel modulators

    International Nuclear Information System (INIS)

    Cunha, Saraghina M.D.; Oliveira, Ramon G. de; Vasconcellos, Mario L.A.A.

    2013-01-01

    In this work, a microwave-assisted synthesis study by microwave irradiation to produce indolizine-2-carbonitrile and indolizine-2-carboxylate in good to high yields (70 and 81%, respectively) in one step from Morita-Baylis-Hillman adducts (MBHA) is presented. These compounds were subsequently transformed to high yields (94 to 100%, respectively) in three 2-indolizine derivatives. The five synthesized compounds were designed in silico aiming to present potential selective activities as ion channel modulators. These activities were suggested by the score values using Molinspiration Cheminformatics program. (author)

  16. Microwave-assisted convenient syntheses of 2-indolizine derivatives from Morita-Baylis-Hillman adducts: new in silico potential ion channel modulators

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Saraghina M.D.; Oliveira, Ramon G. de; Vasconcellos, Mario L.A.A., E-mail: mlaav@quimica.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Quimica

    2013-03-15

    In this work, a microwave-assisted synthesis study by microwave irradiation to produce indolizine-2-carbonitrile and indolizine-2-carboxylate in good to high yields (70 and 81%, respectively) in one step from Morita-Baylis-Hillman adducts (MBHA) is presented. These compounds were subsequently transformed to high yields (94 to 100%, respectively) in three 2-indolizine derivatives. The five synthesized compounds were designed in silico aiming to present potential selective activities as ion channel modulators. These activities were suggested by the score values using Molinspiration Cheminformatics program. (author)

  17. Microwave synthesis and electrochemical properties of lithium manganese borate as cathode for lithium ion batteries

    Science.gov (United States)

    Ma, Ting; Muslim, Arzugul; Su, Zhi

    2015-05-01

    Nano structured LiMnBO3/C cathode materials are synthesized by a fast microwave solid-state reaction method using MnCO3, Li2CO3, H3BO3 and glucose as starting materials for the first time. The crystal structure, morphology and electrochemical properties of LiMnBO3/C composites are characterized by X-ray diffraction (XRD), raman spectroscopy (Ramon), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge-discharge tests. The result shows that not only monoclinic LiMnBO3/C but also hexagonal LiMnBO3/C cathode materials can be successfully synthesized by microwave solid-state method with power of 240 W in different time. Compared with h-LiMnBO3/C and mixed phase LiMnBO3/C, m-LiMnBO3/C displays lower charge-transfer resistance and the Warburg impedance, so it reveals a higher first discharge capacity of 156.3 mAh g-1 at 0.05 C within 1.8V-4.6 V, The value increases up to 173.2 mAh g-1 caused by the activation process. Even after 50 cycles, the discharge capacity of m-LiMnBO3/C still remains at 148.2 mAh g-1.

  18. Synthesis And Characterization Of An Ion Imprinted Polymer For Cadmium Using Quinaldic Acid As Complexing Agent And Applying By Microwave

    Directory of Open Access Journals (Sweden)

    Asmawati

    2015-01-01

    Full Text Available Abstract A Cd2 Ion Imprinted Polymer Cd-IIP has been synthesized by copolymerizaton of cadmium ion quinaldic acid complexing agent 4-vynil pyridine monomer dimethyl sulfoxide solvent ethyleneglycoldimethacrylate EGDMA cross-linker and 22-azobis-isobutyronitrile AIBN initiator. Polymerization was conducted using a microwave at a temperature of 70 oC with heating times of 45 minutes. The template Cd2 was removed by leaching the template with ethanol and 4 M HCl washed by aquabidest and dried in an oven at the temperature of 60oC. The polymer particles imprinted and nonimprinted were characterized using fourir transform infrared FTIR spectroscopy scanning electron microscopy SEM and energy dispersive spectroscopy EDS. The result showed that using heating time 45 minutes at temperature 70 oC the particle morphology is viewed like as the large homogeneous. So the imprinted polymer had bands at 3483 cm-1 1726 cm-1 and 1155 cm-1 indicating the presence of OH CO and C-O respectively.

  19. Microwave annealing effect for highly reliable biosensor: dual-gate ion-sensitive field-effect transistor using amorphous InGaZnO thin-film transistor.

    Science.gov (United States)

    Lee, In-Kyu; Lee, Kwan Hyi; Lee, Seok; Cho, Won-Ju

    2014-12-24

    We used a microwave annealing process to fabricate a highly reliable biosensor using amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs), which usually experience threshold voltage instability. Compared with furnace-annealed a-IGZO TFTs, the microwave-annealed devices showed superior threshold voltage stability and performance, including a high field-effect mobility of 9.51 cm(2)/V·s, a low threshold voltage of 0.99 V, a good subthreshold slope of 135 mV/dec, and an outstanding on/off current ratio of 1.18 × 10(8). In conclusion, by using the microwave-annealed a-IGZO TFT as the transducer in an extended-gate ion-sensitive field-effect transistor biosensor, we developed a high-performance biosensor with excellent sensing properties in terms of pH sensitivity, reliability, and chemical stability.

  20. High microwave performance ion-implanted GaAs MESFETs on InP substrates

    International Nuclear Information System (INIS)

    Wada, M.; Kato, K.

    1990-01-01

    Ion implantation was employed, for the first time, in fabricating GaAs MESFETs in undoped 2 μm thick GaAs epitaxial layers directly grown on InP substrates by low-pressure MOVPE. The Si-ion-implanted GaAs layer on InP substrates showed excellent electrical characteristics: a mobility of 4300 cm 2 /Vs with a carrier density of 2 x 10 17 cm -3 at room temperature. The MESFET (0.8 μm gate length) exhibited a current-gain cutoff frequency of 25 GHz and a maximum frequency of oscillation of 53 GHz, the highest values yet reported to GaAs MESFETs on InP substrates. These results demonstrate the high potential of ion-implanted MESFETs as electronic devices for high-speed InP-based OEICs. (author)

  1. Enhanced production of electron cyclotron resonance plasma by exciting selective microwave mode on a large-bore electron cyclotron resonance ion source with permanent magnet.

    Science.gov (United States)

    Kimura, Daiju; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-01

    We are constructing a tandem type ECRIS. The first stage is large-bore with cylindrically comb-shaped magnet. We optimize the ion beam current and ion saturation current by a mobile plate tuner. They change by the position of the plate tuner for 2.45 GHz, 11-13 GHz, and multi-frequencies. The peak positions of them are close to the position where the microwave mode forms standing wave between the plate tuner and the extractor. The absorbed powers are estimated for each mode. We show a new guiding principle, which the number of efficient microwave mode should be selected to fit to that of multipole of the comb-shaped magnets. We obtained the excitation of the selective modes using new mobile plate tuner to enhance ECR efficiency.

  2. Enhanced production of electron cyclotron resonance plasma by exciting selective microwave mode on a large-bore electron cyclotron resonance ion source with permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Daiju, E-mail: kimura@nf.eie.eng.osaka-u.ac.jp; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

    2014-02-15

    We are constructing a tandem type ECRIS. The first stage is large-bore with cylindrically comb-shaped magnet. We optimize the ion beam current and ion saturation current by a mobile plate tuner. They change by the position of the plate tuner for 2.45 GHz, 11–13 GHz, and multi-frequencies. The peak positions of them are close to the position where the microwave mode forms standing wave between the plate tuner and the extractor. The absorbed powers are estimated for each mode. We show a new guiding principle, which the number of efficient microwave mode should be selected to fit to that of multipole of the comb-shaped magnets. We obtained the excitation of the selective modes using new mobile plate tuner to enhance ECR efficiency.

  3. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries

    Science.gov (United States)

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-07-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2-5 nm pores) and high surface area (457 m2/g), providing numerous active sites for Li+ insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte-electrode interface, and improved structural stability against the local volume change during Li+ insertion-extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization.

  4. Creation and behavior of radicals and ions in the Acetylene/Argon microwave ECR discharge

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Petr; Musil, Jindřich; Novotný, Michal; Lančok, Ján; Fitl, Přemysl; Vlček, Jan

    2017-01-01

    Roč. 14, č. 12 (2017), s. 1-9, č. článku 1700062. ISSN 1612-8850 R&D Projects: GA ČR GA17-13427S; GA MŠk LO1409; GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : acetylene * ECR discharge * ions * mass spectrometry * radicals Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.846, year: 2016

  5. In-situ synthesis of reduced graphene oxide modified lithium vanadium phosphate for high-rate lithium-ion batteries via microwave irradiation

    International Nuclear Information System (INIS)

    Wang, Zhaozhi; Guo, Haifu; Yan, Peng

    2015-01-01

    Highlights: • Graphene-decorated Li 3 V 2 (PO 4 ) 3 is synthesized via microwave irradiation. • Both Li 3 V 2 (PO 4 ) 3 and RGO can be simultaneously achieved through this route. • The GO is reduced by microwave irradiation not the carbon. • Li 3 V 2 (PO 4 ) 3 /RGO displays excellent high-rate ability and cyclic stability. - Abstract: We report a simple and rapid method to synthesize graphene-modified Li 3 V 2 (PO 4 ) 3 as cathode material for lithium-ion batteries via microwave irradiation. By treating graphene oxide and the precursor of Li 3 V 2 (PO 4 ) 3 in a commercial microwave oven, both reduced graphene oxide and Li 3 V 2 (PO 4 ) 3 could be simultaneously synthesized within 5 min. The structure, morphology and electrochemical performances of as-synthesized graphene-modified Li 3 V 2 (PO 4 ) 3 are investigated systematically by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, charge/discharge tests, electrochemical impedance spectra (EIS) and cyclic voltammetry (CV). The XRD result indicates that single-phase graphene-modified Li 3 V 2 (PO 4 ) 3 with monoclinic structure can be obtained. Both SEM and TEM images show that Li 3 V 2 (PO 4 ) 3 nanocrystals are embedded in the reduced graphene oxide sheets which could provide an easy path for the electrons and Li-ions during the cycling process. Compared with the pristine Li 3 V 2 (PO 4 ) 3 electrode, graphene-modified Li 3 V 2 (PO 4 ) 3 exhibits a better high-rate ability and cyclic stability. These superior electrochemical performances are attributed to the good conductivity of reduced graphene oxide which enhances the electrons and Li-ions transport on the surface of Li 3 V 2 (PO 4 ) 3 . Thus, this simple and rapid method could be promising to synthesize graphene-modified electrode materials

  6. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source

    International Nuclear Information System (INIS)

    Kumar, Narender; Rodrigues, G.; Lakshmy, P. S.; Mathur, Y.; Ahuja, R.; Kanjilal, D.; Baskaran, R.

    2014-01-01

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the “off-resonance” mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied

  7. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Narender; Rodrigues, G., E-mail: gerosro@gmail.com; Lakshmy, P. S.; Mathur, Y.; Ahuja, R.; Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi (India); Baskaran, R. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

    2014-02-15

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the “off-resonance” mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied.

  8. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source.

    Science.gov (United States)

    Kumar, Narender; Rodrigues, G; Lakshmy, P S; Baskaran, R; Mathur, Y; Ahuja, R; Kanjilal, D

    2014-02-01

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the "off-resonance" mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied.

  9. High-current beam transport in electrostatic accelerator tubes

    International Nuclear Information System (INIS)

    Ramian, G.; Elais, L.

    1987-01-01

    The UCSB Free Electron Laser (FEL) has successfully demonstrated the use of a commercial 6 megavolt electrostatic accelerator as a high current beam source in a recirculating configuration. The accelerator, manufactured by National Electrostatics Corp. (NEC), Middleton WI, uses two standard high gradient accelerator tubes. Suppression of ion multiplication was accomplished by NEC with apertures and a shaped electrostatic field. This field shaping has fortuitously provided a periodically reversing radial field component with sufficient focusing strength to transport electron beams of up to 3 Amps current. Present two-stage FEL work requires a 20 Amp beam and proposed very high voltage FEL designs require currents as high as 100 Amps. A plan to permit transport of such high current beams by the addition of solenoidal focussing elements is described

  10. Energy confinement in a high-current reversed field pinch

    International Nuclear Information System (INIS)

    An, Z.G.; Lee, G.S.; Diamond, P.H.

    1985-07-01

    The ion temperature gradient driven (eta/sub i/) mode is proposed as a candidate for the cause of anomalous transport in high current reversed field pinches. A 'four-field' fluid model is derived to describe the coupled nonlinear evolution of resistive interchange and eta/sub i/ modes. A renormalized theory is discussed, and the saturation level of the fluctuations is analytically estimated. Transport scalings are obtained, and their implications discussed. In particular, these results indicate that pellet injection is a potentially viable mechanism for improving energy confinement in a high temperature RFP

  11. Development of RF-linac and storage ring system for high-current experiments at GSI

    International Nuclear Information System (INIS)

    Hofmann, I.

    1986-08-01

    The heavy ion facility under construction at GSI is suitable for the generation of high-current beams. It consists of a new high-current injector into the Unilac and a synchrotron and storage ring. We discuss the capability of this system to produce short pulses of heavy ions with a specific energy of the order of 0.1 MJ/g. Under these conditions the system allows to perform a first generation of heavy ion driven target experiments and to test most of the critical issues of a large scale heavy ion fusion driver facility. (orig.)

  12. High current beam transport with multiple beam arrays

    International Nuclear Information System (INIS)

    Kim, C.H.

    1985-05-01

    Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple beam ion induction linac (MBE-4) is being constructed at LBL which will permit study of multiple beam transport arrays, and acceleration and bunch length compression of individually focused beamlets. Various design considerations of MBE-4 regarding scaling laws, nonlinear effects, misalignments, and transverse and longitudinal space charge effects are summarized. Some aspects of longitudinal beam dynamics including schemes to generate the accelerating voltage waveforms and to amplify beam current are also discussed

  13. Development of high current electron beam generator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook [and others

    1997-05-01

    A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs.

  14. Development of high current electron beam generator

    International Nuclear Information System (INIS)

    Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook

    1997-05-01

    A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs

  15. Urchin-like CdS/ZrO2 nanocomposite prepared by microwave-assisted hydrothermal combined with ion-exchange and its multimode photocatalytic activity

    Science.gov (United States)

    Li, Li; Wang, Lili; Zhang, Wenzhi; Zhang, Xiuli; Chen, Xi; Dong, Xue

    2014-12-01

    A series of urchin-like CdS/ZrO2 nanocomposites with different mole ratios of Cd/Zr were prepared by a two-step method combining the microwave-assisted hydrothermal and ion exchange methods. The products were characterized by X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption-desorption measurements. The results of the study revealed that the CdS/ZrO2 nanocomposites had mixed phases of tetragonal ZrO2 and hexagonal CdS. Moreover, the samples prepared by the microwave-assisted hydrothermal method possessed the urchin-like structure with a surface composed of protrude-like nanoparticles in large quantities. The absorption in the visible region changed slightly with increasing mole ratio of Cd/Zr. Moreover, compared to the nanocomposites prepared by the conventional heating, the nanocomposites prepared by the microwave-assisted hydrothermal synthesis showed significantly different Brunauer-Emmett-Teller values, and the urchin-like CdS/ZrO2 structures were obtained. The photocatalytic degradation of methyl orange under ultraviolet (UV) light irradiation indicated that the photocatalytic activity of the CdS/ZrO2 nanocomposite with CdS/ZrO2 molar ratio of 30 % was higher than those of CdS, ZrO2, and other different ratios of CdS/ZrO2 nanocomposites. Moreover, under UV light, visible light, and microwave-assisted multimode photocatalytic degradation, the urchin-like CdS/ZrO2 nanocomposites significantly affected the photodegradation of various dyes. To understand the possible reaction mechanism of the photocatalysis by the CdS/ZrO2 nanocomposites, a series of controlled experiments were performed, and the stability and reusability of the CdS/ZrO2 nanocomposites were further investigated by the photocatalytic reaction.

  16. Urchin-like CdS/ZrO2 nanocomposite prepared by microwave-assisted hydrothermal combined with ion-exchange and its multimode photocatalytic activity

    International Nuclear Information System (INIS)

    Li, Li; Wang, Lili; Zhang, Wenzhi; Zhang, Xiuli; Chen, Xi; Dong, Xue

    2014-01-01

    A series of urchin-like CdS/ZrO 2 nanocomposites with different mole ratios of Cd/Zr were prepared by a two-step method combining the microwave-assisted hydrothermal and ion exchange methods. The products were characterized by X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N 2 adsorption–desorption measurements. The results of the study revealed that the CdS/ZrO 2 nanocomposites had mixed phases of tetragonal ZrO 2 and hexagonal CdS. Moreover, the samples prepared by the microwave-assisted hydrothermal method possessed the urchin-like structure with a surface composed of protrude-like nanoparticles in large quantities. The absorption in the visible region changed slightly with increasing mole ratio of Cd/Zr. Moreover, compared to the nanocomposites prepared by the conventional heating, the nanocomposites prepared by the microwave-assisted hydrothermal synthesis showed significantly different Brunauer–Emmett–Teller values, and the urchin-like CdS/ZrO 2 structures were obtained. The photocatalytic degradation of methyl orange under ultraviolet (UV) light irradiation indicated that the photocatalytic activity of the CdS/ZrO 2 nanocomposite with CdS/ZrO 2 molar ratio of 30 % was higher than those of CdS, ZrO 2 , and other different ratios of CdS/ZrO 2 nanocomposites. Moreover, under UV light, visible light, and microwave-assisted multimode photocatalytic degradation, the urchin-like CdS/ZrO 2 nanocomposites significantly affected the photodegradation of various dyes. To understand the possible reaction mechanism of the photocatalysis by the CdS/ZrO 2 nanocomposites, a series of controlled experiments were performed, and the stability and reusability of the CdS/ZrO 2 nanocomposites were further investigated by the photocatalytic reaction

  17. Effect of Er{sup 3+} ions on the phase formation and properties of In{sub 2}O{sub 3}nanostructures crystallized upon microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Samantha C.S.; Romeiro, Fernanda C.; Paula, Leonardo F. de [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Gonçalves, Rosana F. [UNIFESP, Universidade Federal de São Paulo, 09972-270 Diadema, SP (Brazil); Moura, Ana P. de [LIEC, Instituto de Química, Universidade Estadual Paulista, 14800-900 Araraquara, SP (Brazil); Ferrer, Mateus M.; Longo, Elson [INCTMN-UFSCar, Universidade Federal de São Carlos, 13565-905 São Carlos, SP (Brazil); Patrocinio, Antonio Otavio T. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Lima, Renata C., E-mail: rclima@ufu.br [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil)

    2017-05-15

    Regular sized nanostructures of indium oxide (In{sub 2}O{sub 3}) were homogeneously grown using a facile route, i.e. a microwave-hydrothermal method combined with rapid thermal treatment in a microwave oven. The presence of Er{sup 3+} doping plays an important role in controlling the formation of cubic (bcc) and rhombohedral (rh) In{sub 2}O{sub 3} phases. The samples presented broad photoluminescent emission bands in the green-orange region, which were attributed to the recombination of electrons at oxygen vacancies. The photocatalytic activities of pure bcc-In{sub 2}O{sub 3} and a bcc-rh-In{sub 2}O{sub 3} mixture towards the UVA degradation of methylene blue (MB) were also evaluated. The results showed that Er{sup +3} doped In{sub 2}O{sub 3} exhibited the highest photocatalytic activity with a photonic efficiency three times higher than the pure oxide. The improved performance was attributed to the higher surface area, the greater concentration of electron traps due the presence of the dopant and the possible formation of heterojunctions between the cubic and rhombohedral phases. - Graphical abstract: Photodegradation curves as a function of irradiation time of the samples obtained upon rapid microwave heating. - Highlights: • Efficient and rapid microwave heating to obtain Er{sup 3+} doped In{sub 2}O{sub 3} nanostructures. • Er{sup 3+} ions doping is fundamental to stabilizing the crystalline rhombohedral phase. • Symmetry breaking induced by vacancies in the lattice leads to photoluminescence. • Surface area of doped sample was two times higher than the surface of pure oxide. • The presence of defects in the lattice structure favors photocatalytic activity.

  18. Application of optical emission spectroscopy to high current proton sources

    International Nuclear Information System (INIS)

    Castro, G; Mazzaglia, M; Nicolosi, D; Mascali, D; Reitano, R; Celona, L; Leonardi, O; Leone, F; Naselli, E; Neri, L; Torrisi, G; Gammino, S; Zaniol, B

    2017-01-01

    Optical Emission Spectroscopy (OES) represents a very reliable technique to carry out non-invasive measurements of plasma density and plasma temperature in the range of tens of eV. With respect to other diagnostics, it also can characterize the different populations of neutrals and ionized particles constituting the plasma. At INFN-LNS, OES techniques have been developed and applied to characterize the plasma generated by the Flexible Plasma Trap, an ion source used as 'testbench' of the proton source built for European Spallation Source. This work presents the characterization of the parameters of a hydrogen plasma in different conditions of neutral pressure, microwave power and magnetic field profile, along with perspectives for further upgrades of the OES diagnostics system. (paper)

  19. Microwave Ovens

    Science.gov (United States)

    ... Products and Procedures Home, Business, and Entertainment Products Microwave Ovens Share Tweet Linkedin Pin it More sharing ... 1030.10 - Microwave Ovens Required Reports for the Microwave Oven Manufacturers or Industry Exemption from Certain Reporting ...

  20. Quench properties of high current superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Garber, M; Sampson, W B

    1980-01-01

    A technique has been developed which allows the simultaneous determination of most of the important parameters of a high current superconductor. The critical current, propagation velocity, normal state resistivity, magnetoresistance, and enthalpy are determined as a function of current and applied field. The measurements are made on non-inductive samples which simulate conditions in full scale magnets. For wide, braided conductors the propagation velocity was found to vary approximately quadratically with current in the 2 to 5 kA region. A number of conductors have been tested including some Nb/sub 3/Sn braids which have critical currents in excess of 10 kA at 5 T, 4.2 K.

  1. LASL high-current proton storage rings

    International Nuclear Information System (INIS)

    Lawrence, G.P.; Cooper, R.K.; Hudgings, D.W.; Spalek, G.; Jason, A.J.; Higgins, E.F.; Gillis, R.E.

    1980-01-01

    The Proton Storage Ring at LAMPF is a high-current accumulator designed to convert long 800-MeV linac pulses into very short high-intensity proton bunches ideally suited to driving a pulsed polyenergetic neutron source. The Ring, authorized for construction at $19 million, will operate in a short-bunch high-frequency mode for fast neutron physics and a long-bunch low-frequency mode for thermal neutron-scattering programs. Unique features of the project include charge-changing injection with initial conversion from H - to H 0 , a high repetition rate fast-risetime extraction kicker, and high-frequency and first-harmonic bunching system

  2. High current high accuracy IGBT pulse generator

    International Nuclear Information System (INIS)

    Nesterov, V.V.; Donaldson, A.R.

    1995-05-01

    A solid state pulse generator capable of delivering high current triangular or trapezoidal pulses into an inductive load has been developed at SLAC. Energy stored in a capacitor bank of the pulse generator is switched to the load through a pair of insulated gate bipolar transistors (IGBT). The circuit can then recover the remaining energy and transfer it back to the capacitor bank without reversing the capacitor voltage. A third IGBT device is employed to control the initial charge to the capacitor bank, a command charging technique, and to compensate for pulse to pulse power losses. The rack mounted pulse generator contains a 525 μF capacitor bank. It can deliver 500 A at 900V into inductive loads up to 3 mH. The current amplitude and discharge time are controlled to 0.02% accuracy by a precision controller through the SLAC central computer system. This pulse generator drives a series pair of extraction dipoles

  3. Microwave engineering

    CERN Document Server

    Pozar, David M

    2012-01-01

    The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A large

  4. Rare earth ions doped polyaniline/cobalt ferrite nanocomposites via a novel coordination-oxidative polymerization-hydrothermal route: Preparation and microwave-absorbing properties

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chunming; Jiang, Junjun; Liu, Xiaohua; Yin, Chengjie; Deng, Cuifen

    2016-04-15

    Polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} (RE=La, Ce, Y, x=0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca. 10–20 nm. Microwave absorption properties of polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa{sub x}Fe{sub 2−x}O{sub 4} nanocomposite, the optimal microwave absorption performance is at x=0.15, that is, the mass ratio of La in CoLa{sub x}Fe{sub 2−x}O{sub 4} is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. - Graphical abstract: Scheme PAn/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites prepared via a novel coordination-oxidative polymerization-hydrothermal route. - Highlights: • An organic–inorganic hybrid―polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} (RE=La, Ce, Y, x=0.05–0.25) nanocomposites was prepared via a novel coordination-oxidative polymerization-hydrothermal route. • The as-prepared polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites exhibit excellent microwave absorbing performance compared with the composites prepared by using conventional method. • The novel method reported in this work could

  5. Rare earth ions doped polyaniline/cobalt ferrite nanocomposites via a novel coordination-oxidative polymerization-hydrothermal route: Preparation and microwave-absorbing properties

    International Nuclear Information System (INIS)

    Yang, Chunming; Jiang, Junjun; Liu, Xiaohua; Yin, Chengjie; Deng, Cuifen

    2016-01-01

    Polyaniline/CoRE_xFe_2_−_xO_4 (RE=La, Ce, Y, x=0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca. 10–20 nm. Microwave absorption properties of polyaniline/CoRE_xFe_2_−_xO_4 nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa_xFe_2_−_xO_4 nanocomposite, the optimal microwave absorption performance is at x=0.15, that is, the mass ratio of La in CoLa_xFe_2_−_xO_4 is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. - Graphical abstract: Scheme PAn/CoRE_xFe_2_−_xO_4 nanocomposites prepared via a novel coordination-oxidative polymerization-hydrothermal route. - Highlights: • An organic–inorganic hybrid―polyaniline/CoRE_xFe_2_−_xO_4 (RE=La, Ce, Y, x=0.05–0.25) nanocomposites was prepared via a novel coordination-oxidative polymerization-hydrothermal route. • The as-prepared polyaniline/CoRE_xFe_2_−_xO_4 nanocomposites exhibit excellent microwave absorbing performance compared with the composites prepared by using conventional method. • The novel method reported in this work could be employed to prepare other conductive polymers/inorganic nanocomposites as well.

  6. Macrofilament simulation of high current beam transport

    International Nuclear Information System (INIS)

    Hayden, R.J.; Jakobson, M.J.

    1985-01-01

    Macrofilament simulation of high current beam transport through a series of solenoids has been used to investigate the sensitivity of such calculations to the initial beam distribution and to the number of filaments used in the simulation. The transport line was tuned to approximately 105 0 phase advance per cell at zero current with a tune depression of 65 0 due to the space charge. Input distributions with the filaments randomly uniform throughout a four dimensional ellipsoid and K-V input distributions have been studied. The behavior of the emittance is similar to that published for quadrupoles with like tune depression. The emittance demonstrated little growth in the first twelve solenoids, a rapid rate of growth for the next twenty, and a subsequent slow rate of growth. A few hundred filaments were sufficient to show the character of the instability. The number of filaments utilized is an order of magnitude fewer than has been utilized previously for similar instabilities. The previously published curves for simulations with less than a thousand particles show a rather constant emittance growth. If the solenoid transport line magnetic field is increased a few percent, emittance growth curves are obtained not unlike those curves. Collision growth effects are less important than indicated in the previously published results for quadrupoles

  7. MAXILAC as a high current UNILAC injector

    International Nuclear Information System (INIS)

    Ungrin, J.; Klabunde, J.

    1984-08-01

    MAXILAC, an RFQ of split coaxial resonator design, will deliver heavy ion currents in the 20-30 mA range with energies in the 100-150 keV/u range. One proposed method of coupling this RFQ to UNILAC is to divide the first tank of the Wideroee section into two segments and to inject the MAXILAC beam for acceleration starting with the second segment. This injection scheme has been investigated in detail with the beam dynamics codes MIKRO, PARMT and PARMI. Other injection schemes are also considered. (orig.)

  8. Magnetic and microwave absorption properties of rare earth ions (Sm{sup 3+}, Er{sup 3+}) doped strontium ferrite and its nanocomposites with polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Juhua, E-mail: luojuhua@163.com [School of Materials Engineering, Yancheng Institute of Technology, Yancheng 224051 (China); Xu, Yang; Mao, Hongkai [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2015-05-01

    M-type strontium ferrite substituted by RE (RE=Sm{sup 3+}, Er{sup 3+}) were prepared via a sol–gel method. Polypyrrole (PPy)/ferrite nanocomposites (with 20 wt% ferrite) were prepared by in situ polymerization method in the presence of ammonium persulfate. Effect of the substituted RE ions on structure, magnetic properties and microwave absorption properties were investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and vector network analyzer. All XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. The crystallite size of synthesized particle is within the range of 22.2–38.1 nm. The structural in character of the composites were investigated with FT-IR analysis. It shows that the ferrite successfully packed by PPy. TEM photographs show that the particle size had grown up to 50–100 nm after coating with PPy. In the magnetization for the PPy/SrSm{sub 0.3}Fe{sub 11.7}O{sub 19} (SrEr{sub 0.3}Fe{sub 11.7}O{sub 19}) composites, the coercivity (H{sub c}) of the composites both increased compared with the undoped composite while the saturation magnetization (M{sub s}) appeared opposite change with different RE ions. Considering the electromagnetic loss and impedance matching comprehensively, the Er-doped ferrite/PPy composite got the better microwave absorption performance with the maximum RL value of −24.01 dB in 13.8 GHz at 3.0 mm. And its width (<−10 dB) has reached 7.2 GHz which has covered the whole Ku band. - Highlights: • The influence of RE ions on the structure of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on the magnetic properties of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on electromagnetic losses of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • PPy/SrEr{sub 0.3}Fe{sub 11.7}O{sub 19} possessed the excellent absorption property.

  9. Microwave hydrothermal synthesis of urchin-like NiO nanospheres as electrode materials for lithium-ion batteries and supercapacitors with enhanced electrochemical performances

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Anjon Kumar, E-mail: Anjon.K.Mondal@student.uts.edu.au [Centre for Clean Energy Technology, School of Chemistry and Forensic Science, University of Technology Sydney, Broadway, Sydney, NSW 2007 (Australia); Su, Dawei; Wang, Ying; Chen, Shuangqiang [Centre for Clean Energy Technology, School of Chemistry and Forensic Science, University of Technology Sydney, Broadway, Sydney, NSW 2007 (Australia); Liu, Qi [School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Wang, Guoxiu, E-mail: Guoxiu.wang@uts.edu.au [Centre for Clean Energy Technology, School of Chemistry and Forensic Science, University of Technology Sydney, Broadway, Sydney, NSW 2007 (Australia)

    2014-01-05

    Highlights: • Urchin-like NiO nanospheres were synthesised by a microwave hydrothermal method. • The NiO nanospheres consist of nanocrystals and porous structure. • NiO nanospheres exhibited a high reversible specific capacity of 1027 mA h g{sup −1}. • The NiO nanospheres also delivered a high supercapacitance of 736 F g{sup −1}. -- Abstract: Urchin-like NiO nanospheres were synthesised by a microwave hydrothermal method. The as-synthesised NiO nanospheres were characterised by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. It was found that NiO nanosphere consists of a nanoporous structure and nanosize crystals. When applied as anode materials in lithium-ion batteries, NiO nanospheres exhibited a high reversible specific capacity of 1027 mA h g{sup −1}, an excellent cycling performance and a good high rate capability. NiO nanospheres also showed a high specific capacitance as electrode materials for supercapacitors.

  10. Microwave-Assisted Preparation and Characterization of a Polyoxometalate-Based Inorganic 2D Framework Anode for Enhancing Lithium-Ion Battery Performance.

    Science.gov (United States)

    Nie, Yan-Mei; Liang, Shuang; Yu, Wei-Dong; Yuan, Hao; Yan, Jun

    2018-05-04

    A pure inorganic 2D network molybdophosphate, [Mn 3 Mo 12 O 24 (OH) 6 (HPO 3 ) 8 (H 2 O) 6 ] 4- (1 a), synthesized through microwave irradiation with the existence of Mn 2+ and organic cations and isolated as [(CH 3 ) 2 NH 2 ] 3 Na[Mn 3 Mo 12 O 24 (OH) 6 (HPO 3 ) 8 (H 2 O) 6 ]⋅12 H 2 O (1), is found to possess highly enhanced performance in lithium-ion batteries' anode materials. The molecule shows multielectron redox properties suitable for producing anode materials with a specific capacity of 602 mA h g -1 at 100 mA g -1 after 50 cycles in lithium-ion batteries, although its specific capacity is the highest among all the reported pure inorganic 2D polyoxometalates to date, the cyclic stability is not that satisfactory. A hybrid nanocomposite of this 2D network and polypyrrole cations effectively reduces the capacity fading in initial cycles, and increases the stability and improves the electrochemical performance of lithium-ion batteries as well. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Microwave-assisted reactive sintering and lithium ion conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

    Science.gov (United States)

    Hallopeau, Leopold; Bregiroux, Damien; Rousse, Gwenaëlle; Portehault, David; Stevens, Philippe; Toussaint, Gwenaëlle; Laberty-Robert, Christel

    2018-02-01

    Li1.3Al0.3Ti1.7(PO4)3 (LATP) materials are made of a three-dimensional framework of TiO6 octahedra and PO4 tetrahedra, which provides several positions for Li+ ions. The resulting high ionic conductivity is promising to yield electrolytes for all-solid-state Li-ion batteries. In order to elaborate dense ceramics, conventional sintering methods often use high temperature (≥1000 °C) with long dwelling times (several hours) to achieve high relative density (∼90%). In this work, an innovative synthesis and processing approach is proposed. A fast and easy processing technique called microwave-assisted reactive sintering is used to both synthesize and sinter LATP ceramics with suitable properties in one single step. Pure and crystalline LATP ceramics can be achieved in only 10 min at 890 °C starting from amorphous, compacted LATP's precursors powders. Despite a relative density of 88%, the ionic conductivity measured at ambient temperature (3.15 × 10-4 S cm-1) is among the best reported so far. The study of the activation energy for Li+ conduction confirms the high quality of the ceramic (purity and crystallinity) achieved by using this new approach, thus emphasizing its interest for making ion-conducting ceramics in a simple and fast way.

  12. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  13. HIGH-CURRENT ERL-BASED ELECTRON COOLING FOR RHIC

    International Nuclear Information System (INIS)

    BEN-ZVI, I.

    2005-01-01

    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 and 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

  14. Monodisperse porous LiFePO4/C microspheres derived by microwave-assisted hydrothermal process combined with carbothermal reduction for high power lithium-ion batteries

    Science.gov (United States)

    Chen, Rongrong; Wu, Yixiong; Kong, Xiang Yang

    2014-07-01

    A microwave-assisted hydrothermal approach combined with carbothermal reduction has been developed to synthesize monodisperse porous LiFePO4/C microspheres, which possess the diameter range of 1.0-1.5 μm, high tap density of ∼1.3 g cm-3, and mesoporous characteristic with Brunauer-Emmett-Teller (BET) surface area of 30.6 m2 g-1. The obtained microspheres show meatball-like morphology aggregated by the carbon-coated LiFePO4 nanoparticles. The electrochemical impedance spectra (EIS) results indicate that carbon coating can effectively enhance both of the electronic and ionic conductivities for LiFePO4/C microspheres. The Li-ion diffusion coefficient of the LiFePO4/C microspheres calculated from the cyclic voltammetry (CV) curves is ∼6.25 × 10-9 cm2 s-1. The electrochemical performance can achieve about 100 and 90 mAh g-1 at 5C and 10C charge/discharge rates, respectively. As cathode material, the as-prepared LiFePO4/C microspheres show excellent rate capability and cycle stability, promising for high power lithium-ion batteries.

  15. Microwave-Assisted Synthesis of NiCo2O4 Double-Shelled Hollow Spheres for High-Performance Sodium Ion Batteries

    Science.gov (United States)

    Zhang, Xiong; Zhou, Yanping; Luo, Bin; Zhu, Huacheng; Chu, Wei; Huang, Kama

    2018-03-01

    The ternary transitional metal oxide NiCo2O4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo2O4 double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt, and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized product was tested as an anode material in a sodium ion battery, was found to exhibit a high reversible specific capacity of 511 mAh g-1 at 100 mA g-1, and deliver high capacity retention after 100 cycles. [Figure not available: see fulltext.

  16. Microwave Irradiation

    Indian Academy of Sciences (India)

    Way to Eco-friendly, Green Chemistry. Rashmi ... The rapid heating of food in the kitchen using microwave ovens ... analysis; application to waste treatment; polymer technology; ... of microwave heating in organic synthesis since the first contri-.

  17. Selective adsorption behavior of Cd(II) ion imprinted polymers synthesized by microwave-assisted inverse emulsion polymerization: Adsorption performance and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Fang, E-mail: zhufang@tyut.edu.cn [College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024 (China); Li, Luwei [College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024 (China); Xing, Junde [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024 (China)

    2017-01-05

    Highlights: • Microwave assisted inverse emulsion polymerization was applied to prepare Cd(II) imprinted polymers. • The adsorption capacity was evaluated by static adsorption experiments. • Pseudo-second-order model and Langmuir adsorption isotherm model had the best agreement with the experimental data. • The adsorption was a spontaneous and endothermic process. • Cd(II) imprinted polymers have specific identification for Cd(II). - Abstract: Microwave-assisted inverse emulsion polymerization method was used to prepare Cd(II) imprinted polymer (IIP) by using β-cyclodextrin (β-CD) and acrylamide (AM) as functional monomer, epichlorohydrin (ECH) as crossing-linking agent, ammonium persulfate as initiator. The Cd(II) imprinted polymer was characterized by SEM, FTIR and TGA. The influences of initial concentration of Cd(II), pH values, temperature, time and competitive ions on adsorption capacity and recognition properties are investigated. Under the optimal conditions, the adsorption capacity could reach 107 mg/g. Furthermore, pseudo first order kinetic model, pseudo second order kinetic model and intra-particular diffusion model were used to describe the adsorption kinetic behavior. Results showed that the pseudo-second-order model (R{sup 2} 0.9928–0.9961) had the best agreement with the experimental data. Langmuir adsorption isotherm model described the experimental data well, which indicated that adsorption was mainly monolayer absorption. Moreover, the study of adsorption thermodynamics (ΔG{sup 0} < 0, ΔH{sup 0} > 0, ΔS{sup 0} > 0) suggested that the adsorption process was a spontaneous and endothermic process. Competitive selectivity experiment revealed that imprinted polymer could selectively recognize Cd(II). It provides a new idea for removing Cd(II) from aqueous solution.

  18. Selective adsorption behavior of Cd(II) ion imprinted polymers synthesized by microwave-assisted inverse emulsion polymerization: Adsorption performance and mechanism

    International Nuclear Information System (INIS)

    Zhu, Fang; Li, Luwei; Xing, Junde

    2017-01-01

    Highlights: • Microwave assisted inverse emulsion polymerization was applied to prepare Cd(II) imprinted polymers. • The adsorption capacity was evaluated by static adsorption experiments. • Pseudo-second-order model and Langmuir adsorption isotherm model had the best agreement with the experimental data. • The adsorption was a spontaneous and endothermic process. • Cd(II) imprinted polymers have specific identification for Cd(II). - Abstract: Microwave-assisted inverse emulsion polymerization method was used to prepare Cd(II) imprinted polymer (IIP) by using β-cyclodextrin (β-CD) and acrylamide (AM) as functional monomer, epichlorohydrin (ECH) as crossing-linking agent, ammonium persulfate as initiator. The Cd(II) imprinted polymer was characterized by SEM, FTIR and TGA. The influences of initial concentration of Cd(II), pH values, temperature, time and competitive ions on adsorption capacity and recognition properties are investigated. Under the optimal conditions, the adsorption capacity could reach 107 mg/g. Furthermore, pseudo first order kinetic model, pseudo second order kinetic model and intra-particular diffusion model were used to describe the adsorption kinetic behavior. Results showed that the pseudo-second-order model (R"2 0.9928–0.9961) had the best agreement with the experimental data. Langmuir adsorption isotherm model described the experimental data well, which indicated that adsorption was mainly monolayer absorption. Moreover, the study of adsorption thermodynamics (ΔG"0 0, ΔS"0 > 0) suggested that the adsorption process was a spontaneous and endothermic process. Competitive selectivity experiment revealed that imprinted polymer could selectively recognize Cd(II). It provides a new idea for removing Cd(II) from aqueous solution.

  19. A directly coupled monolithic rectangular resonator forming a robust microwave plasma ion source for SIFT-MS

    International Nuclear Information System (INIS)

    Spanel, P; Hall, E F H; Workman, C T; Smith, D

    2004-01-01

    A simple ion source is described that consists of a glass discharge tube positioned judiciously in a rectangular waveguide resonator that is directly coupled to an under-run standard magnetron. This ion source operates well with gas mixtures, including rare gases, air and water vapour in the pressure range 10-100 Pa and at magnetron powers within the range 15-40 W. The main advantage of this magnetron/cavity arrangement is the absence of mechanically adjustable parts (aerial and tuning stub), in contrast to other commonly used arrangements that combine a cavity resonator that is connected to the magnetron via a launcher and a coaxial cable

  20. A directly coupled monolithic rectangular resonator forming a robust microwave plasma ion source for SIFT-MS

    Energy Technology Data Exchange (ETDEWEB)

    Spanel, P [Trans Spectra Limited, 9 The Elms, Newcastle under Lyme, ST5 8RP (United Kingdom); Hall, E F H [Trans Spectra Limited, 9 The Elms, Newcastle under Lyme, ST5 8RP (United Kingdom); Workman, C T [Trans Spectra Limited, 9 The Elms, Newcastle under Lyme, ST5 8RP (United Kingdom); Smith, D [Trans Spectra Limited, 9 The Elms, Newcastle under Lyme, ST5 8RP (United Kingdom)

    2004-05-01

    A simple ion source is described that consists of a glass discharge tube positioned judiciously in a rectangular waveguide resonator that is directly coupled to an under-run standard magnetron. This ion source operates well with gas mixtures, including rare gases, air and water vapour in the pressure range 10-100 Pa and at magnetron powers within the range 15-40 W. The main advantage of this magnetron/cavity arrangement is the absence of mechanically adjustable parts (aerial and tuning stub), in contrast to other commonly used arrangements that combine a cavity resonator that is connected to the magnetron via a launcher and a coaxial cable.

  1. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Kozue; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2015-06-01

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d{sup 6}4p (3d{sup 5}4s4p) excited levels of iron ion broadly over an energy range of 7.6–9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels. - Highlights: • This paper describes the excitation mechanism of iron ion in Okamoto-cavity MIP in comparison with conventional ICP. • Boltzmann distribution is studied among iron ionic lines of

  2. A high-current pulsed cathodic vacuum arc plasma source

    International Nuclear Information System (INIS)

    Oates, T.W.H.; Pigott, J.; Mckenzie, D.R.; Bilek, M.M.M.

    2003-01-01

    Cathodic vacuum arcs (CVAs) are well established as a method for producing metal plasmas for thin film deposition and as a source of metal ions. Fundamental differences exist between direct current (dc) and pulsed CVAs. We present here results of our investigations into the design and construction of a high-current center-triggered pulsed CVA. Power supply design based on electrolytic capacitors is discussed and optimized based on obtaining the most effective utilization of the cathode material. Anode configuration is also discussed with respect to the optimization of the electron collection capability. Type I and II cathode spots are observed and discussed with respect to cathode surface contamination. An unfiltered deposition rate of 1.7 nm per pulse, at a distance of 100 mm from the source, has been demonstrated. Instantaneous plasma densities in excess of 1x10 19 m -3 are observed after magnetic filtering. Time averaged densities an order of magnitude greater than common dc arc densities have been demonstrated, limited by pulse repetition rate and filter efficiency

  3. R and D status of high-current accelerators at IFP

    International Nuclear Information System (INIS)

    Deng, J. J.; Shi, J. S.; Xie, W. P.

    2011-01-01

    High-current accelerators have many important applications in Z-pinches, high-power microwaves, and free electron lasers, imploding liners and radiography and so on. Research activities on Z-pinches, imploding liners, radiography at the Institute of Fluid Physics (IFP) are introduced. Several main high-current accelerators developed and being developed at IFP are described, such as the Linear Induction Accelerator X-Ray Facility Upgrade (LIAXFU, 12 MeV, 2.5 kA, 90 ns), the Dragon-I linear induction accelerator (20 MeV, 2.5 kA, 60 ns), and the Primary Test Stand for Z-pinch (PTS, 10 MA, 120 ns). The design of Dragon-II linear induction accelerator (20 MeV, 2.5 kA, 3 x 60 ns) to be built will be presented briefly.

  4. Intermittent microwave heating synthesized high performance spherical LiFePO4/C for Li-ion batteries

    International Nuclear Information System (INIS)

    Zou, Hongli; Zhang, Guanghui; Shen, Pei Kang

    2010-01-01

    An intermittent microwave heating method was used to synthesize spherical LiFePO 4 /C in the presence of glucose as reductive agent and carbon source without the use of the inert gas in the oven processes. The FePO 4 was used as iron precursor to reduce the cost and three lithium salts of Li 2 CO 3 , LiOH and CH 3 COOLi were chosen for comparison of the resulting materials. The materials can be alternatively heated by this method at a temperature controllable mode for crystallization and phase transformation and to provide relaxation time for protecting particles growth. The X-ray diffraction and scanning electron microscope measurements confirmed that the LiFePO 4 /C is olivine structured with the average particle size of 50-100 nm. The spherical LiFePO 4 /C as cathode material showed better electrochemical performance in terms of the specific capacity and the cycling stability, which might be attributed to the highly crystallized phase, small particle distribution and improved conductivity by carbon connection.

  5. Rapid Polyol-Assisted Microwave Synthesis of Nanocrystalline LiFePO4/C Cathode for Lithium-Ion Batteries.

    Science.gov (United States)

    Paul, Baboo Joseph; Gim, Jihyeon; Baek, Sora; Kang, Jungwon; Song, Jinju; Kim, Sungjin; Kim, Jaekook

    2015-08-01

    Nanocrystalline LiFePO4/C has been synthesized under a very short period of time (90 sec) using a polyol-assisted microwave heating synthesis technique. The X-ray diffraction (XRD) data indicates that the rapidly synthesized materials correspond to phase pure olivine. Post-annealing of the as-prepared sample at 600 °C in argon atmosphere yields highly crystalline LiFePO4/C. The morphology of the samples studied using scanning electron microscopy (SEM) reveals the presence of secondary particles formed from aggregation of primary particles in the range of 30-50 nm. Transmission electron microscopy (TEM) images reveal a thin carbon layer coating on the surface of the primary particle. The charge/discharge studies indicate that the as-prepared and annealed LiFePO4/C samples delivered initial discharge capacities of 126 and 160 mA h g-1, respectively, with good capacity retentions at 0.05 mA cm-2 current densities. The post-annealing process indeed improves the crystallinity of the LiFePO4 nanocrystals, which enhances the electrode performance of LiFePO4/C.

  6. PASOTRON high-energy microwave source

    Science.gov (United States)

    Goebel, Dan M.; Schumacher, Robert W.; Butler, Jennifer M.; Hyman, Jay, Jr.; Santoru, Joseph; Watkins, Ron M.; Harvey, Robin J.; Dolezal, Franklin A.; Eisenhart, Robert L.; Schneider, Authur J.

    1992-04-01

    A unique, high-energy microwave source, called PASOTRON (Plasma-Assisted Slow-wave Oscillator), has been developed. The PASOTRON utilizes a long-pulse E-gun and plasma- filled slow-wave structure (SWS) to produce high-energy pulses from a simple, lightweight device that utilizes no externally produced magnetic fields. Long pulses are obtained from a novel E-gun that employs a low-pressure glow discharge to provide a stable, high current- density electron source. The electron accelerator consists of a high-perveance, multi-aperture array. The E-beam is operated in the ion-focused regime where the plasma filling the SWS space-charge neutralizes the beam, and the self-pinch force compresses the beamlets and increases the beam current density. A scale-model PASOTRON, operating as a backward- wave oscillator in C-band with a 100-kV E-beam, has produced output powers in the 3 to 5 MW range and pulse lengths of over 100 microsecond(s) ec, corresponding to an integrated energy per pulse of up to 500 J. The E-beam to microwave-radiation power conversion efficiency is about 20%.

  7. Total iodine quantification in fluids and tissues from iodine- or iodide-supplemented rats by ion chromatography following microwave-assisted digestion.

    Science.gov (United States)

    Delgado, Guadalupe; Muñoz-Torres, Carolina; Orozco-Esquivel, Teresa; Anguiano, Brenda; Aceves, Carmen

    2015-03-01

    Iodine is a crucial component of thyroid hormones, and several reports have shown that iodine per se is implicated in the physiopathology of other organs. Innovative ion chromatography detection following a four-step temperature ramp microwave digestion in 25-50 mM nitric acid was developed to measure total iodine in biological fluids and tissue samples from female Sprague-Dawley rats supplemented with 0.05% molecular iodine (I2) or 0.05% potassium iodide (I(-)) in drinking water. The reported method allows the measurement of total iodine with a limit of quantification of 13.7 μg L(-1), recoveries of 96.3-100.3%, and intra- and inter-assay variations, of 3.5% and 7.4% respectively. Analysis of biological fluids showed that after 48 hours, iodine-supplemented animals exhibited significantly higher levels of total iodine in both serum and urine compared with those supplemented with iodide. The half-life of iodine in serum and urine measured over the first 48 h showed similar patterns for both the I2 (7.89 and 7.76 hours) and I(-) (8.27 and 8.90 hours) supplements. Differential uptake patterns were observed in tissues after 6 days of supplements, with I(-) preferentially retained by thyroid, lactating mammary gland, and milk, and a slightly but significantly higher capture of I2 in pituitary, ovary, and virgin mammary gland. We developed a rapid, selective, and accurate digestion method to process fluid and tissue samples that permits reproducible measurements of total iodine by ion chromatography; iodine or iodide supplement show a similar serum and urine half-life, but organ-specific uptake depends on the chemical form of the iodine supplement.

  8. Stable superconducting magnet. [high current levels below critical temperature

    Science.gov (United States)

    Boom, R. W. (Inventor)

    1967-01-01

    Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training.

  9. Energy and composition of the ion flux in microwave electron cyclotron resonance/radio frequency methan plasma

    Czech Academy of Sciences Publication Activity Database

    Mišina, Martin; Pokorný, Petr

    173-174, - (2003), s. 914-917 ISSN 0257-8972. [International Conference on Plasma Surface Engineering/11./. Garmisch-Partenkirchen, 09.09.2002-13.09.2002] R&D Projects: GA MŠk ME 455; GA ČR GA106/99/D086 Grant - others:NATO(XX) SfP974354 Institutional research plan: CEZ:AV0Z1010914 Keywords : mass spectrometry * ion energy * methane * PE CVD Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.410, year: 2003

  10. Microwave undulator

    International Nuclear Information System (INIS)

    Batchelor, K.

    1986-03-01

    The theory of a microwave undulator utilizing a plane rectangular waveguide operating in the TE/sub 10n/ mode and other higher order modes is presented. Based on this, a possible undulator configuration is analyzed, leading to the conclusion that the microwave undulator represents a viable option for undulator wavelength down to about 1 cm where peak voltage and available microwave power considerations limit effectiveness. 4 refs., 4 figs

  11. Microwave Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Makes ultra-high-resolution field measurements. The Microwave Microscope (MWM) has been used in support of several NRL experimental programs involving sea...

  12. Microwave-assisted aqueous synthesis of transition metal ions doped ZnSe/ZnS core/shell quantum dots with tunable white-light emission

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie [Laboratory of Advanced Materials, Fudan University, Shanghai 200438 (China); Chen, Qiuhang; Zhang, Wanlu; Mei, Shiliang; He, Liangjie; Zhu, Jiatao [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China); Chen, Guoping [School of Information Science and Technology, Fudan University, Shanghai 200433 (China); Guo, Ruiqian, E-mail: rqguo@fudan.edu.cn [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China)

    2015-10-01

    Highlights: • ZnSe-based QDs were formed via a microwave-assisted aqueous approach. • The stabilizer, ZnS coats and UV irradiation played a role in the PL enhancement. • Tunable white-light-emitting Mn:ZnSe QDs and Cu,Mn:ZnSe/ZnS QDs were synthesized. • The formation mechanism of Cu,Mn:ZnSe QDs was clarified. • The corresponding CIE color coordinates of different PL spectra were obtained. - Abstract: Synthesis of bright white-light emitting Mn and Cu co-doped ZnSe/ZnS core/shell quantum dots (QDs) (Cu,Mn:ZnSe/ZnS) was reported. Water-soluble ZnSe-based QDs with Mn and Cu doping were prepared using a versatile hot-injection method in aqueous solution with a microwave-assisted approach. Influence of the Se/S ratio, stabilizer, refluxing time and the concentration of Cu/Mn dopant ions on the particle size and photoluminescence (PL) were investigated. The as-prepared QDs in the different stages of growth were characterized by X-ray powder diffractometer (XRD), high-resolution transmission electron microscopy (HRTEM), UV–visible (UV–vis) spectrophotometer, and fluorescence spectrophotometer. It is found that these ZnSe-based QDs synthesized under mild conditions exhibit emission in the range of 390–585 nm. The PL quantum yield (QY) of the as-prepared water-soluble ZnSe QDs can be up to 24.3% after the UV-irradiation treatment. The band-gap emission of ZnSe is effectively restrained through Mn and Cu doping. The refluxing time influences the doping of not only Mn, but also Cu, which leads to the best refluxing time of Mn:ZnSe and the red-shift of the emission of Cu:ZnSe d-dots. Co-doping induced white-light emission (WLE) from Cu,Mn:ZnSe/ZnS core/shell QDs were obtained, which can offer the opportunity for future-generation white-light emitting diodes (LEDs)

  13. Measurements of actinometry and ions energy in a microwave discharge; Mediciones de actinometria y energia de iones en una descarga de microondas

    Energy Technology Data Exchange (ETDEWEB)

    Becerril, F.; Camps, E. [Instituto Nacional de Investigaciones Nucleares, Departamento de Fisica, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Villagran, M. [CI-UNAM, Mexico D.F. (Mexico); Muhl, S. [IIM-UNAM, Mexico D.F. (Mexico)

    1998-07-01

    In the present work it is showed the implementation of the plasma diagnostic technique through actinometry which allows to determine the absolute density of excited species. It is showed the range of the technique application, for the case of N{sub 2}-H{sub 2} mixtures plasmas used for the metals nitridation. The effects of magnetic field and the work pressure over ions energy were determined, using a Faraday cup type energy analyser. The results showed that in our device it is possible to vary such energy in a range between 10-45 eV, which amplify the range of applications perceptibly in comparison with another type of discharges. (Author)

  14. High-voltage high-current triggering vacuum switch

    International Nuclear Information System (INIS)

    Alferov, D.F.; Bunin, R.A.; Evsin, D.V.; Sidorov, V.A.

    2012-01-01

    Experimental investigations of switching and breaking capacities of the new high current triggered vacuum switch (TVS) are carried out at various parameters of discharge current. It has been shown that the high current triggered vacuum switch TVS can switch repeatedly a current from units up to ten kiloampers with duration up to ten millisecond [ru

  15. Analytical study on discrete model of virtual cathode in a high-current diode

    International Nuclear Information System (INIS)

    Privezentsev, A.P.

    1988-01-01

    Interest in investigation of virtual cathode dynamics related to the development of high-current accelerator equipment is caused by the possibility of its application for ion collective acceleration in direct high-current electron beams and generation of power electromagnetic radiation. The Hamiltonian form of a plane sheet model for a high-current flux in a plane diode is investigated. Variables used permit to carry out the investigation of dynamics of the virtual cathode flux by the method of coordinate point transformations in a phase space. The necessity of numerical integration of sheet motion equations is dropped out in this case. Analytical solution of the suggested iterative circuit for total flux passage is presented as an example. The solution obtained is equivalent to the known results of the plane diode theory, obtained in the hydrodynamic approximation

  16. Fundamental properties of secondary negative ion emission by sputtering

    International Nuclear Information System (INIS)

    Shimizu, Toshiki; Tsuji, Hiroshi; Ishikawa, Junzo

    1989-01-01

    The report describes some results obtained from preliminary experiments on secondary negative ion emission from a cesiated surface by Xe-ion beam sputtering, which give the production probability. A measuring system is constructed for secondary negative ion emission. The system consists of a microwave ion source with a lens, a sputtering target holder with a heater, a cesium oven, a limiting aperture with a substrate for deposition, a negative-ion extractor and lens, and a ExB type mass separator. Observations are made on the dependence of negative ion current on cesium supply, dependence of negative ion current on target temperature, and negative ion production probability. The cesium supply and the target temperature are found to strongly influence the negative ion emission. By controlling these factors, the optimum condition for secondary negative ion emission is achieved with a minimum surface work function. The production probability of the negative ion is found to be very high, about 20% for carbon. Therefore, the secondary negative ion emission is considered a useful and highly efficient method to obtain high current ion beams. The constant in the Rasser's theoretical equation is experimentally determined to be 4.1 x 10 -4 eV sec/m. (N.K.)

  17. Transverse emittance measurement of high-current single pulse beams using pepper-pot method

    International Nuclear Information System (INIS)

    Ke Jianlin; Zhou Changgeng; Qiu Rui

    2013-01-01

    A pepper pot-imaging plate system has been developed and used to measure the 4-D transverse emittance of a vacuum arc ion source. Single beam pulses of tens to hundreds milliamperes were extracted from the plasma with 64 kV high voltage. An imaging plate was laid after the pepper pot to visualize the ion beamlets passing though the holes on the pepper pot. An application program was developed to show the phase-space distribution and calculate the ellipse and RMS emittances. The normalized RMS emittances are about 6.41 π·mm·mrad in x-direction and 4.61 π·mm·mrad in y-direction. It is shown that the emittance of the vacuum arc ion source is much larger than that of other types of ion sources, which is mainly attributed to the high current and the convex meniscus of this source. (authors)

  18. Microwave Measurements

    CERN Document Server

    Skinner, A D

    2007-01-01

    The IET has organised training courses on microwave measurements since 1983, at which experts have lectured on modern developments. Their lecture notes were first published in book form in 1985 and then again in 1989, and they have proved popular for many years with a readership beyond those who attended the courses. The purpose of this third edition of the lecture notes is to bring the latest techniques in microwave measurements to this wider audience. The book begins with a survey of the theory of current microwave circuits and continues with a description of the techniques for the measureme

  19. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  20. Microwave-assisted synthesis of HKUST-1 and functionalized HKUST-1-@H3PW12O40: selective adsorption of heavy metal ions in water analyzed with synchrotron radiation.

    Science.gov (United States)

    Zou, Fang; Yu, Runhan; Li, Rongguan; Li, Wei

    2013-08-26

    A simple, rapid and efficient synthesis of the metal-organic framework (MOF) HKUST-1 [Cu3(1,3,5-benzene-tri-carboxilic-acid)2] by microwave irradiation is described, which afforded a homogeneous and highly selective material. The unusually short time to complete the synthesis by microwave irradiation is mainly attributable to rapid nucleation rather than to crystal growth rate. Using this method, HKUST-1-MW (MW=microwave) could be prepared within 20 min, whereas by hydrothermal synthesis, involving conventional heating, the preparation time is 8 h. Work efficiency was improved by the good performance of the obtained HKUST-1-MW which exhibited good selective adsorption of heavy metal ions, as well as a remarkably high adsorption affinity and adsorption capacity, but no adsorption of Hg(2+) under the same experimental conditions. Of particular importance is the preservation of the structure after metal-ion adsorption, which remained virtually intact, with only a few changes in X-ray diffraction intensity and a moderate decline in surface area. Synthesis of the polyoxometalate-containing HKUST-1-MW@H3PW12O40 afforded a MOF with enhanced stability in water, due to the introduced Keggin-type phosphotungstate, which systematically occluded in the cavities constituting the walls between the mesopores. Different Cu/W ratios were investigated according to the extrusion rate of cooper ions concentration, without significant structural changes after adsorption. The MOFs obtained feature particle sizes between 10-20 μm and their structures were determined using synchrotron-based X-ray diffraction. The results of this study can be considered important for potentially wider future applications of MOFs, especially to attend environmental issues. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Measurement technology of RF interference current in high current system

    Science.gov (United States)

    Zhao, Zhihua; Li, Jianxuan; Zhang, Xiangming; Zhang, Lei

    2018-06-01

    Current probe is a detection method commonly used in electromagnetic compatibility. With the development of power electronics technology, the power level of power conversion devices is constantly increasing, and the power current of the electric energy conversion device in the electromagnetic launch system can reach 10kA. Current probe conventionally used in EMC (electromagnetic compatibility) detection cannot meet the test requirements on high current system due to the magnetic saturation problem. The conventional high current sensor is also not suitable for the RF (Radio Frequency) interference current measurement in high current power device due to the high noise level in the output of active amplifier. In this paper, a passive flexible current probe based on Rogowski coil and matching resistance is proposed that can withstand high current and has low noise level, to solve the measurement problems of interference current in high current power converter. And both differential mode and common mode current detection can be easily carried out with the proposed probe because of the probe's flexible structure.

  2. High-current relativistic klystron amplifier development for microsecond pulse lengths

    International Nuclear Information System (INIS)

    Fazio, M.V.; Carlsten, B.E.; Faehl, R.; Kwan, T.J.; Rickel, D.G.; Stringfield, R.M.; Tallerico, P.J.

    1991-01-01

    Los Alamos is extending the performance of the Friedman-type, high-current relativistic klystron amplifier (RKA) to the microsecond regime while attempting to achieve the gigawatt-level peak power capability that has been characteristic of the RKA at shorter pulse lengths. Currently the electron beam power into the device is about 1 GW in microsecond duration pulses, with an effort underway to increase the beam power to 2.5 GW. To data the device has yielded an rf modulated electron beam power of 350 MW, with up to 50 MW coupled into waveguide. Several aspects of RKA operation under investigation that affect RKA beam bunching efficiency and amplifier gain include cavity tuning, beam diameter, beam current, and input rf drive power, and the development of an output coupler that efficiently couples the microwave power from the low impedance beam into rectangular waveguide operating in the dominant mode. Current results from experimental testing and code modeling are presented

  3. Design and experiment of high-current low-pressure plasma-cathode e-gun

    International Nuclear Information System (INIS)

    Xie Wenkai; Li Xiaoyun; Wang Bin; Meng Lin; Yan Yang; Gao Xinyan

    2006-01-01

    The preliminary design of a new high-power low pressure plasma-cathode e-gun is presented. Based on the hollow cathode effect and low-pressure glow discharge empirical formulas, the hollow cathode, the accelerating gap, and the working gas pressure region are given. The general experimental device of the low-pressure plasma cathode electron-gun generating high current density e-beam source is shown. Experiments has been done in continuous filled-in gases and gases-puff condition, and the discharging current of 150-200 A, the width of 60 μs and the collector current of 30-80 A, the width of 60 μs are obtained. The results show that the new plasma cathode e-gun can take the place of material cathode e-gun, especially in plasma filled microwave tubes. (authors)

  4. New Pulsed Power Technology for High Current Accelerators

    International Nuclear Information System (INIS)

    Caporaso, G J

    2002-01-01

    Recent advances in solid-state modulators now permit the design of a new class of high current accelerators. These new accelerators will be able to operate in burst mode at frequencies of several MHz with unprecedented flexibility and precision in pulse format. These new modulators can drive accelerators to high average powers that far exceed those of any other technology and can be used to enable precision beam manipulations. New insulator technology combined with novel pulse forming lines and switching may enable the construction of a new type of high gradient, high current accelerator. Recent developments in these areas will be reviewed

  5. Design of high current injector for SPring-8

    International Nuclear Information System (INIS)

    Yoshikawa, H.; Nakamura, N.; Mizuno, A.; Suzuki, S.; Hori, T.; Yanagida, K.; Mashiko, K.; Yokomizo, H.

    1992-01-01

    The linac of SPring-8, large synchrotron radiation facility of Japan, has the option which is positron operation modes. The electron gun of this linac is designed on base of the optimization for a high current beam to get positrons as many as possible. But otherwise this linac should be used as an accurate electron beam generator for commissioning on the whole facility. This report shows differences of the beam specification between a high current beam and a low current beam. The bunching section of this linac has just been constructed this summer at Tokai-Lab. of JAERI to be confirmed with the specification. (author). 3 refs., 1 tab., 4 figs

  6. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Muhammad; Alshemary, Ammar Z.; Goh, Yi-Fan; Wan Ibrahim, Wan Aini [Department of Chemistry, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Lintang, Hendrik O. [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia)

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca{sup 2+} ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA.

  7. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    International Nuclear Information System (INIS)

    Akram, Muhammad; Alshemary, Ammar Z.; Goh, Yi-Fan; Wan Ibrahim, Wan Aini; Lintang, Hendrik O.; Hussain, Rafaqat

    2015-01-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca 2+ ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA

  8. A high current, high speed pulser using avalanche transistors

    International Nuclear Information System (INIS)

    Hosono, Yoneichi; Hasegawa, Ken-ichi

    1985-01-01

    A high current, high speed pulser for the beam pulsing of a linear accelerator is described. It uses seven avalanche transistors in cascade. Design of a trigger circuit to obtain fast rise time is discussed. The characteristics of the pulser are : (a) Rise time = 0.9 ns (FWHM) and (d) Life time asymptotically equals 2000 -- 3000 hr (at 50 Hz). (author)

  9. High current betatron research at the University of New Mexico

    International Nuclear Information System (INIS)

    Humphries, S. Jr.; Len, L.K.

    1987-01-01

    Betatrons are among the simplest of high energy accelerators. Their circuit is equivalent to a step-up transformer; the electron beam forms a multi-turn secondary winding. Circulation of the beam around the flux core allows generation of high energy electrons with relatively small core mass. As with any transformer, a betatron is energy inefficient at low beam current; the energy balance is dominated by core losses. This fact has prompted a continuing investigation of high current betatrons as efficient, compact sources of beta and gamma radiation. A program has been supported at the University of New Mexico by the Office of Naval Research to study the physics of high current electron beams in circular accelerators and to develop practical technology for high power betatrons. Fabrication and assembly of the main ring was completed in January of this year. In contrast to other recent high current betatron experiments the UNM device utilizes a periodic focusing system to contain high current beams during the low energy phase of the acceleration cycle. The reversing cusp fields generated by alternating polarity solenoidal lenses cancel beam drift motions induced by machine errors. In consequence, they have found that the cusp geometry has had significantly better stability properties than a monodirectional toroidal field. In comparison to other minimum-Β geometries such as the Stelllatron cusps have open field lines which facilitate beam injection and neutralization

  10. Electron gun for formation of two high-current beams

    International Nuclear Information System (INIS)

    Borisov, A.R.; Zherlitsyn, A.G.; Mel'nikov, G.V.; Shtejn, Yu.G.

    1982-01-01

    The design of the ''Tonus'' accelerator electron gun for formation of two high-current beams aiming at the production of the maximum beam power and density is described. The results of investigation of two modes of beam formation are presented. In the first variant the beams were produced by means of two plane diodes with 40 mm diameter cathodes made of stainless steel and anodes made of 50 μm thick titanium foil. In the second variant the beams were formed by means of two coaxial diodes with magnetic insulation. In one diode the cathode diameter equals to 74 mm, the anode diameter - 92 mm, in the other diode 16 and 44 mm respectively. Current redistribution in the diodes and its effect on accelerating voltage are investigated. It is shown that the gun permits formation of synchronized two high-current beams, iaving equal electron energied. Wide range current control of both beams is possible

  11. High-current power supply for accelerator magnets

    International Nuclear Information System (INIS)

    Bourkland, K.R.; Winje, R.A.

    1978-01-01

    A power supply for controlling the current to accelerator magnets produces a high current at a precisely controlled time rate of change by varying the resonant frequency of an RLC circuit that includes the magnet and applying the current to the magnet during a predetermined portion of the waveform of an oscillation. The current is kept from going negative despite the reverse-current characteristics of thyristors by a quenching circuit

  12. Use of high current density superconducting coils in fusion devices

    International Nuclear Information System (INIS)

    Green, M.A.

    1979-11-01

    Superconducting magnets will play an important role in fusion research in years to come. The magnets which are currently proposed for fusion research use the concept of cryostability to insure stable operation of the superconducting coils. This paper proposes the use of adiabatically stable high current density superconducting coils in some types of fusion devices. The advantages of this approach are much lower system cold mass, enhanced cryogenic safety, increased access to the plasma and lower cost

  13. Application of RF Superconductivity to High-Current Linac

    International Nuclear Information System (INIS)

    Chan, K.C.D.

    1998-01-01

    In 1997, the authors initiated a development program in Los Alamos for high-current superconducting proton-linac technology to build prototypes components of this linac to demonstrate the feasibility. The authors are building 700-MHz niobium cavities with elliptical shapes, as well as power couplers to transfer high RF power to these cavities. The cavities and power couplers will be integrated in cryostats as linac cryomodules. In this paper, they describe the linac design and the status of the development program

  14. New initiatives for producing high current electron accelerators

    International Nuclear Information System (INIS)

    Faehl, R.J.; Keinigs, R.K.; Pogue, E.W.

    1996-01-01

    New classes of compact electron accelerators able to deliver multi-kiloamperes of pulsed 10-50 MeV electron beams are being studied. One class is based upon rf linac technology with dielectric-filled cavities. For materials with ε/ε o >>1, the greatly increased energy storage permits high current operation. The second type is a high energy injected betatron. Circulating current limits scale as Β 2 γ 3

  15. Hall probe for measuring high currents in superconducting coils

    International Nuclear Information System (INIS)

    Ferendeci, A.M.

    1986-01-01

    Constructional details of a compact Hall probe for measuring high currents in superconducting coils are given. The Hall probe is easy to assemble and can be inserted or removed from the system without breaking the superconducting loop. Upper current limit of the probe can be increased by using larger magnetic core material. Shielding becomes necessary if the probe holder is to be placed near large current dependent magnetic fields

  16. High Current Ionic Diode Using Homogeneously Charged Asymmetric Nanochannel Network Membrane.

    Science.gov (United States)

    Choi, Eunpyo; Wang, Cong; Chang, Gyu Tae; Park, Jungyul

    2016-04-13

    A high current ionic diode is achieved using an asymmetric nanochannel network membrane (NCNM) constructed by soft lithography and in situ self-assembly of nanoparticles with uniform surface charge. The asymmetric NCNM exhibits high rectified currents without losing a rectification ratio because of its ionic selectivity gradient and differentiated electrical conductance. Asymmetric ionic transport is analyzed with diode-like I-V curves and visualized via fluorescent dyes, which is closely correlated with ionic selectivity and ion distribution according to variation of NCNM geometries.

  17. Monodisperse Ni{sub x}Fe{sub 3-x}O{sub 4} nanospheres: Metal-ion-steered size/composition control mechanism, static magnetic and enhanced microwave absorbing properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Kedan, E-mail: 17858961652@163.com [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Liu, Yun, E-mail: liuyun650403@163.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Pan, Yefei, E-mail: 3083780256@qq.com [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Wang, Ru, E-mail: 631081137@qq.com [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Hu, Panbing, E-mail: 1036855954@qq.com [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); He, Rujia, E-mail: 634185782@qq.com [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Zhang, Lingli, E-mail: 786510121@qq.com [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Tong, Guoxiu, E-mail: tonggx@zjnu.cn [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China)

    2017-05-15

    Highlights: • A metal-ion-steered solvothermal method for synthesizing Ni{sub x}Fe{sub 3-x}O{sub 4} nanospheres. • Proposing an in situ-reduction, coordination-precipitation transformation mechanism. • Investigating size- and composition-dependent static magnetic properties. • Investigating size- and composition-dependent microwave absorbing properties. - Abstract: An easy metal-ion-steered solvothermal method was developed for the one-step synthesis of monodisperse, uniform Ni{sub x}Fe{sub 3-x}O{sub 4} polycrystalline nanospheres with tunable sphere diameter (40–400 nm) and composition (0 ≤ x ≤ 0.245) via changing just Ni{sup 2+}/Fe{sup 3+} molar ratio (γ). With g increased from 0:1 to 2:1, sphere diameter gradually decreased and crystal size exhibited an inversed U-shaped change tendency, followed by increased Ni/Fe atom ratio from 0% to 0.0888%. An in situ-reduction, coordination-precipitation transformation mechanism was proposed to interpret the metal-ion-steered growth. Size- and composition-dependent static magnetic and microwave absorbing properties were systematically investigated. Saturation magnetization declines with g in a Boltzmann model due to the changes of crystal size, sphere diameter, and Ni content. The coercivity reaches a maximum at γ = 0.75:1 because of the critical size of Fe{sub 3}O{sub 4} single domain (25 nm). Studies on microwave absorption reveal that 150–400 nm Fe{sub 3}O{sub 4} nanospheres mainly obey the quarter-wavelength cancellation model with the single-band absorption; 40–135 nm Ni{sub x}Fe{sub 3-x}O{sub 4} nanospheres (0 ≤ x ≤ 0.245) obey the one and three quarter-wavelength cancellation model with the multi-band absorption. 150 nm Fe{sub 3}O{sub 4} nanospheres exhibit the optimal EM wave-absorbing property with an absorbing band of 8.94 GHz and the maximum R{sub L} of −50.11 dB.

  18. Development of a high current H- injector for the proton storage ring at LAMPF

    International Nuclear Information System (INIS)

    York, R.L.; Stevens, R.R.; DeHaven, R.A.; McConnell, J.R.; Chamberlin, E.P.; Kandarian, R.

    1984-01-01

    A new high-current H - injector has been installed at LAMPF for the Proton Storage Ring. The injector is equipped with a multicusp surface-production H - ion source that was developed at LAMPF. The ion source is capable of long-term operation at 20 mA of H - current at 10% duty factor and with normalized beam emittance of 0.08 cm-mrad (95% beam fraction). Details of the development program, the injector design, and initial operating experience are discussed. Included in the discussion is a comparison of intensity and emittance measurements of the same H - beam at 100 keV and 750 keV. 4 references, 6 figures

  19. Development of high current injector for tandem accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Takashi; Iwamoto, Eiji [Nissin - High Voltage Co. Ltd., Kyoto (Japan); Kishimoto, Naoki; Saito, Tetsuya; Mori, Yoshiharu

    1997-02-01

    The development of the electrostatic type tandem accelerators has been carried out so far, but by the recent remarkable progress of negative ion sources, the beam current which was inconceivable so far has become obtainable, and the use as the electrostatic type tandem accelerators is expanding rapidly. The problem which must be solved in the development of a high energy, large current heavy ion injection device is the development of an injector. As to the generation of negative ions, by the development of plasma sputter negative ion sources, the almost satisfactory performance has been obtained in beam current, emittance, life and so on, but as for the transport and control of generated negative ion beam, there is the large problem of spatial charge effect. This time, the verifying test on this problem was carried out, therefore, its contents and results are reported. The equipment which was developed this time was delivered to the Institute for Materials Research. Its specifications are shown. The whole constitution, negative ion source, and beam transport system are described. Beam generation test and spatial charge effect test are reported. The test stand was made, and in the verifying test, the maximum beams of 4 mA in Cu and 3 mA in Ni were able to be generated and transported. The effect of the countermeasures to spatial charge effect was confirmed. (K.I.)

  20. Research of long pulse high current diode radial insulation

    International Nuclear Information System (INIS)

    Tan Jie; Chang Anbi; Hu Kesong; Liu Qingxiang; Ma Qiaosheng; Liu Zhong

    2002-01-01

    A radial insulation structure which is used in long pulse high current diode is introduced. The theory of vacuum flashover and the idea of design are briefly introduced. In the research, cone-shaped insulator was used. The geometry structure parameters were optimized by simulating the static electrical field distribution. Experiment was done on a pulse power source with 200 ns pulse width. The maximum voltage 750 kV was obtained, and the average stand-off electrical field of insulator is about 50 kV/cm

  1. Stability of large orbit, high-current particle rings

    International Nuclear Information System (INIS)

    Lovelace, R.V.E.

    1994-01-01

    A review is made of theory of the low-frequency stability of large orbit, high-current particle rings which continue to be of interest for compact fusion systems. The precession mode was the first mode predicted by Furth and observed by Christofilos to be unstable under certain conditions. Subsequently, many detailed studies have been made of the stability of particle rings- different modes, different ring geometries, systems with/without a toroidal B field, and sytems with/without a current carrying plasma component. The possibly dangerous modes are still thought to include the precession mode, the tilting mode, and the low order kink modes. copyright American Institute of Physics

  2. Research on High Current Pulse Discharges at IPP ASci CR

    Czech Academy of Sciences Publication Activity Database

    Koláček, Karel; Schmidt, Jiří; Prukner, Václav; Štraus, Jaroslav; Frolov, Oleksandr; Martínková, M.

    2006-01-01

    Roč. 56, suppl. B (2006), s. 259-266 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA ČR GA202/06/1324; GA MŠk 1P04LA235 Institutional research plan: CEZ:AV0Z20430508 Keywords : Pulsed high current capillary discharge * amplified spontaneous emission * soft X-ray laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  3. HOM frequency control of SRF cavity in high current ERLs

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan

    2018-03-01

    The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety of Energy Recovery Linac (ERL) applications.

  4. High current proton linear accelerators and nuclear power

    International Nuclear Information System (INIS)

    Tunnicliffe, P.R.; Chidley, B.G.; Fraser, J.S.

    1976-01-01

    This paper outlines a possible role that high-current proton linear accelerators might play as ''electrical breeders'' in the forthcoming nuclear-power economy. A high-power beam of intermediate energy protons delivered to an actinide-element target surrounded by a blanket of fertile material may produce fissile material at a competitive cost. Criteria for technical performance and, in a Canadian context, for costs are given and the major problem areas outlined not only for the accelerator and its associated rf power source but also for the target assembly. (author)

  5. Velocity spread of REB generated by high current diode

    International Nuclear Information System (INIS)

    Vrba, P.

    1994-05-01

    A theoretical analysis and numerical simulations of the Relativistic Electron Beam (REB) generation in a high current diode immersed in an external magnetic field were performed. The calculations confirmed the generated beam to be homogeneous and monoenergetic in a broad central region. In the case of a cylindrical diode the mixing of electron trajectories was only observed in a narrow peripheral beam region. The angle between particle trajectories and the external longitudinal magnetic field varies chaotically form 0 to -25 deg. This phenomenon suppresses the excitation of the two-stream instability excited by REB in a plasma column. (author) 2 tabs., 12 figs., 7 refs

  6. Crane RF accelerator for high current radiation damage studies

    International Nuclear Information System (INIS)

    Whitham, K.; Anamkath, H.; Evans, K.; Lyons, S.; Palmer, D.; Miller, R.; Treas, P.; Zante, T.

    1992-01-01

    An electron accelerator was designed and built for the Naval Weapons Support Center for transient radiation effects on electronics experiments and testing. The Crane L Band RF Electron Linac was designed to provide high currents over a wide range of pulse widths and energies. The energy extends to 60 MeV and pulse widths vary from a few ns to 10 μsec. Beam currents range from 20 amps in the short pulse case to 1.5 amps in the long pulse case. This paper describes the linac, its architecture, the e-gun and pulser, waveguides, klystrons and modulator, vacuum system, beam transport, and control systems. fig., tab

  7. High-current electron accelerator for gas-laser pumping

    Energy Technology Data Exchange (ETDEWEB)

    Badaliants, G R; Mamikonian, V A; Nersisian, G Ts; Papanian, V O

    1978-11-26

    A high-current source of pulsed electron beams has been developed for the pumping of UV gas lasers. The parameters of the device are: energy of 0.3-0.7 MeV pulse duration of 30 ns and current density (in a high-pressure laser chamber) of 40-100 A/sq cm. The principal feature of the device is the use of a rectangular cold cathode with incomplete discharge along the surface of the high-permittivity dielectric. Cathodes made of stainless steel, copper, and graphite were investigated.

  8. Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of three barbiturates in pork by ion trap gas chromatography-tandem mass spectrometry (GC/MS/MS) following microwave assisted derivatization

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Haixiang [College of Science, China Agricultural University, Beijing 100094 (China); Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China); Department of Basic Agricultural Science, Hebei North College, Zhangjiakou Hebei 075131 (China); Wang Liping [College of Science, China Agricultural University, Beijing 100094 (China); Qiu Yueming [Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China); Zhou Zhiqiang [College of Science, China Agricultural University, Beijing 100094 (China)]. E-mail: zqzhou@cau.edu.cn; Zhong Weike [Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China); Li Xiang [Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China)

    2007-03-14

    A new method was developed for the rapid screening and confirmation analysis of barbital, amobarbital and phenobarbital residues in pork by gas chromatography-tandem mass spectrometry (GC/MS/MS) with ion trap MSD. The residual barbiturates in pork were extracted by ultrasonic extraction, cleaned up on a multiwalled carbon nanotubes (MWCNTs) packed solid phase extraction (SPE) cartridge and applied acetone-ethyl acetate (3:7, v/v) mixture as eluting solvent and derivatized with CH{sub 3}I under microwave irradiation. The methylated barbiturates were separated on a TR-5MS capillary column and detected with an ion trap mass detector. Electron impact ion source (EI) operating MS/MS mode was adopted for identification and external standard method was employed for quantification. One precursor ion m/z 169 was selected for analysis of barbital and amobarbital and m/z 232 was selected for phenobarbital. The product ions were obtained under 1.0 V excitation voltage. Good linearities (linear coefficient R > 0.99) were obtained at the range of 0.5-50 {mu}g kg{sup -1}. Limit of detection (LOD) of barbital was 0.2 {mu}g kg{sup -1} and that of amobarbital and phenobarbital were both 0.1 {mu}g kg{sup -1} (S/N {>=} 3). Limit of quatification (LOQ) was 0.5 {mu}g kg{sup -1} for three barbiturates (S/N {>=} 10). Satisfying recoveries ranging from 75% to 96% of the three barbiturates spiked in pork were obtained, with relative standard deviations (R.S.D.) in the range of 2.1-7.8%.

  9. Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of three barbiturates in pork by ion trap gas chromatography-tandem mass spectrometry (GC/MS/MS) following microwave assisted derivatization

    International Nuclear Information System (INIS)

    Zhao Haixiang; Wang Liping; Qiu Yueming; Zhou Zhiqiang; Zhong Weike; Li Xiang

    2007-01-01

    A new method was developed for the rapid screening and confirmation analysis of barbital, amobarbital and phenobarbital residues in pork by gas chromatography-tandem mass spectrometry (GC/MS/MS) with ion trap MSD. The residual barbiturates in pork were extracted by ultrasonic extraction, cleaned up on a multiwalled carbon nanotubes (MWCNTs) packed solid phase extraction (SPE) cartridge and applied acetone-ethyl acetate (3:7, v/v) mixture as eluting solvent and derivatized with CH 3 I under microwave irradiation. The methylated barbiturates were separated on a TR-5MS capillary column and detected with an ion trap mass detector. Electron impact ion source (EI) operating MS/MS mode was adopted for identification and external standard method was employed for quantification. One precursor ion m/z 169 was selected for analysis of barbital and amobarbital and m/z 232 was selected for phenobarbital. The product ions were obtained under 1.0 V excitation voltage. Good linearities (linear coefficient R > 0.99) were obtained at the range of 0.5-50 μg kg -1 . Limit of detection (LOD) of barbital was 0.2 μg kg -1 and that of amobarbital and phenobarbital were both 0.1 μg kg -1 (S/N ≥ 3). Limit of quatification (LOQ) was 0.5 μg kg -1 for three barbiturates (S/N ≥ 10). Satisfying recoveries ranging from 75% to 96% of the three barbiturates spiked in pork were obtained, with relative standard deviations (R.S.D.) in the range of 2.1-7.8%

  10. High current density magnets for INTOR and TIBER

    International Nuclear Information System (INIS)

    Miller, J.R.; Henning, C.D.; Kerns, J.A.; Slack, D.S.; Summers, L.T.; Zbasnik, J.P.

    1986-12-01

    The adoption of high current density, high field, superconducting magnets for INTOR and TIBER would prove beneficial. When combined with improved radiation tolerance of the magnets to minimize the inner leg shielding, a substantial reduction in machine dimensions and capital costs can be achieved. Fortunately, cable-in-conduit conductors (CICC) which are capable of the desired enhancements are being developed. Because conductor stability in a CICC depends more on the trapped helium enthalpy, rather than the copper resistivity, higher current densities of the order of 40 A/mm 2 at 12 T are possible. Radiation damage to the copper stabilizer is less important because the growth in resistance is a second-order effect on stability. Such CICC conductors lend themselves naturally to niobium-tin utilization, with the benefits of the high current-sharing temperature of this material being taken to advantage in absorbing radiation heating. When the helium coolant is injected at near the critical pressure, Joule-Thompson expansion in the flow path tends to stabilize the fluid temperature at under 6 K. Thus, higher fields, as well as higher current densities, can be considered for INTOR or TIBER

  11. Commissioning of the superconducting ECR ion source VENUS at 18 GHz

    International Nuclear Information System (INIS)

    Leitner, Daniela; Abbott, Steven R.; Dwinell, Roger D.; Leitner, Matthaeus; Taylor, Clyde E.; Lyneis, Claude M.

    2004-01-01

    During the last year, the VENUS ECR ion source was commissioned at 18 GHz and preparations for 28 GHz operation are now underway. During the commissioning phase with 18 GHz, tests with various gases and metals have been performed with up to 2000 W RF power. The ion source performance is very promising [1,2]. VENUS (Versatile ECR ion source for Nuclear Science) is a next generation superconducting ECR ion source, designed to produce high current, high charge state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the RIA (Rare Isotope Accelerator) front end. The goal of the VENUS ECR ion source project as the RIA R and D injector is the production of 240e(micro)A of U 30+ , a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5e(micro)A of U 48+ , a low current, very high charge state beam. To meet these ambitious goals, VENUS has been designed for optimum operation at 28 GHz. This frequency choice has several design consequences. To achieve the required magnetic confinement, superconducting magnets have to be used. The size of the superconducting magnet structure implies a relatively large plasma volume. Consequently, high power microwave coupling becomes necessary to achieve sufficient plasma heating power densities. The 28 GHz power supply has been delivered in April 2004

  12. Comparison of electron cloud simulation and experiments in the high-current experiment

    International Nuclear Information System (INIS)

    Cohen, R.H.; Friedman, A.; Covo, M. Kireeff; Lund, S.M.; Molvik, A.W.; Bieniosek, F.M.; Seidl, P.A.; Vay, J.-L.; Verboncoeur, J.; Stoltz, P.; Veitzer, S.

    2004-01-01

    A set of experiments has been performed on the High-Current Experiment (HCX) facility at LBNL, in which the ion beam is allowed to collide with an end plate and thereby induce a copious supply of desorbed electrons. Through the use of combinations of biased and grounded electrodes positioned in between and downstream of the quadrupole magnets, the flow of electrons upstream into the magnets can be turned on or off. Properties of the resultant ion beam are measured under each condition. The experiment is modeled via a full three-dimensional, two species (electron and ion) particle simulation, as well as via reduced simulations (ions with appropriately chosen model electron cloud distributions, and a high-resolution simulation of the region adjacent to the end plate). The three-dimensional simulations are the first of their kind and the first to make use of a timestep-acceleration scheme that allows the electrons to be advanced with a timestep that is not small compared to the highest electron cyclotron period. The simulations reproduce qualitative aspects of the experiments, illustrate some unanticipated physical effects, and serve as an important demonstration of a developing simulation capability

  13. Effect of electrolysis parameters on the morphologies of copper powder obtained at high current densities

    Directory of Open Access Journals (Sweden)

    Orhan Gökhan

    2012-01-01

    Full Text Available The effects of copper ion concentrations and electrolyte temperature on the morphologies and on the apparent densities of electrolytic copper powders at high current densities under galvanostatic regime were examined. These parameters were evaluated by the current efficiency of hydrogen evolution. In addition, scanning electron microscopy was used for analyzing the morphology of the copper powders. It was found that the morphology was dependent over the copper ion concentration and electrolyte temperature under same current density (CD conditions. At 150 mA cm-2 and the potential of 1000±20 mV (vs. SCE, porous and disperse copper powders were obtained at low concentrations of Cu ions (0.120 M Cu2+ in 0.50 M H2SO4. Under this condition, high rate of hydrogen evolution reaction took place parallel to copper electrodeposition. The morphology was changed from porous, disperse and cauliflower-like to coral-like, shrub-like and stalk-stock like morphology with the increasing of Cu ion concentrations towards 0.120 M, 0.155 M, 0.315 M, 0.475 M and 0.630 M Cu2+ in 0.5 M H2SO4 respectively at the same CD. Similarly, as the temperature was increased, powder morphology and apparent density were observed to be changed. The apparent density values of copper powders were found to be suitable for many of the powder metallurgy applications.

  14. Advances in microwaves 8

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 8 covers the developments in the study of microwaves. The book discusses the circuit forms for microwave integrated circuits; the analysis of microstrip transmission lines; and the use of lumped elements in microwave integrated circuits. The text also describes the microwave properties of ferrimagnetic materials, as well as their interaction with electromagnetic waves propagating in bounded waveguiding structures. The integration techniques useful at high frequencies; material technology for microwave integrated circuits; specific requirements on technology for d

  15. Microwave power engineering applications

    CERN Document Server

    Okress, Ernest C

    2013-01-01

    Microwave Power Engineering, Volume 2: Applications introduces the electronics technology of microwave power and its applications. This technology emphasizes microwave electronics for direct power utilization and transmission purposes. This volume presents the accomplishments with respect to components, systems, and applications and their prevailing limitations in the light of knowledge of the microwave power technology. The applications discussed include the microwave heating and other processes of materials, which utilize the magnetron predominantly. Other applications include microwave ioni

  16. High-current beam dynamics and transport, theory and experiment

    International Nuclear Information System (INIS)

    Reiser, M.

    1986-01-01

    Recent progress in the understanding of beam physics and technology factors determining the current and brightness of ion and electron beams in linear accelerators will be reviewed. Topics to be discussed including phase-space density constraints of particle sources, low-energy beam transport include charge neutralization, emittance growth due to mismatch, energy exchange, instabilities, nonlinear effects, and longitudinal bunching

  17. Ultra-high current density thin-film Si diode

    Science.gov (United States)

    Wang, Qi [Littleton, CO

    2008-04-22

    A combination of a thin-film .mu.c-Si and a-Si:H containing diode structure characterized by an ultra-high current density that exceeds 1000 A/cm.sup.2, comprising: a substrate; a bottom metal layer disposed on the substrate; an n-layer of .mu.c-Si deposited the bottom metal layer; an i-layer of .mu.c-Si deposited on the n-layer; a buffer layer of a-Si:H deposited on the i-layer, a p-layer of .mu.c-Si deposited on the buffer layer; and a top metal layer deposited on the p-layer.

  18. High-current proton accelerators-meson factories

    International Nuclear Information System (INIS)

    Dmitrievskij, V.P.

    1979-01-01

    A possibility of usage of accelerators of neutron as well as meson factories is considered. Parameters of linear and cyclic accelerators are given, which are employed as meson factories and as base for developing intense neutron generators. It is emphasized that the principal aim of developing neutron generators on the base of high current proton accelerators is production of intense neutron fluxes with a present energy spectrum. Production of tens-and-hundreds milliampere currents at the energy of 800-1000 MeV is considered at present for two types of accelerating facilities viz. linear accelerators under continuous operating conditions and cyclotrons with strong focusing. Quantitative evaluations of developing high-efficiency linear and cyclic accelerators are considered. The basic parameters of an ccelerating complex are given, viz. linear accelerator-injector and 800 MeV isochronous cyclotron. The main problems associated with their realization are listed [ru

  19. Development of high current beam ns pulsed system

    CERN Document Server

    Shen Guan Ren; Gao Fu; Guan Xia Ling; LiuNaiYi

    2001-01-01

    The development of high current beam ns pulsed system of CPNG and its characteristic, main technological performance and application are introduced. Firstly, important parameters of the system are calculated using theoretical model, the design requirements of some important parts are understood. Some mistakes in physics conception are corrected. Second, the chopper is designed for parallel plate deflector, chopping aperture and sine wave voltage sweeping device. It is emphasized that the conception of parallel plate load impedance is the capacitance load, but not the 50 ohm load impedance. The dynamic capacitance value has been measured. The output emphasizes the output voltage amplitude, but not the output power for sweeping device. The display system of output sweeping voltage was set up and it is sure that the maximum output voltage(V-V) is >=4000 V. The klystron buncher are re-designed. It is emphasized to overcome difficulty of support high voltage electrode in the klystron and insulator of input sine wa...

  20. A High-Current, Stable Nonaqueous Organic Redox Flow Battery

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiaoliang; Duan, Wentao; Huang, Jinhua; Zhang, Lu; Li, Bin; Reed, David; Xu, Wu; Sprenkle, Vincent; Wang, Wei

    2016-10-14

    Nonaqueous redox flow batteries are promising in pursuit of high-energy storage systems owing to the broad voltage window, but currently are facing key challenges such as poor cycling stability and lack of suitable membranes. Here we report a new nonaqueous all-organic flow chemistry that demonstrates an outstanding cell cycling stability primarily because of high chemical persistency of the organic radical redox species and their good compatibility with the supporting electrolyte. A feasibility study shows that Daramic® and Celgard® porous separators can lead to high cell conductivity in flow cells thus producing remarkable cell efficiency and material utilization even at high current operations. This result suggests that the thickness and pore size are the key performance-determining factors for porous separators. With the greatly improved flow cell performance, this new flow system largely addresses the above mentioned challenges and the findings may greatly expedite the development of durable nonaqueous flow batteries.

  1. Method for making a high current fiber brush collector

    Science.gov (United States)

    Scuro, S. J.

    1986-05-01

    An axial-type homopolar motor having high density, high current fiber brush collectors affording efficient, low contact resistance and low operating temperatures is discussed. The collectors include a ring of concentric row of brushes in equally spaced beveled holes soldered in place using a fixture for heating the ring to just below the solder melting point at a soldering iron for the local application of additional heat at each brush. Prior to soldering, an oxide film is formed on the surfaces of the brushes and ring, and the bevels are burnished to form a wetting surface. Flux applied with the solder at each bevel removes to an effective soldering depth the oxide film on the brushes and the holes.

  2. High current precision long pulse electron beam position monitor

    CERN Document Server

    Nelson, S D; Fessenden, T J; Holmes, C

    2000-01-01

    Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.

  3. Rf Gun with High-Current Density Field Emission Cathode

    International Nuclear Information System (INIS)

    Jay L. Hirshfield

    2005-01-01

    High current-density field emission from an array of carbon nanotubes, with field-emission-transistor control, and with secondary electron channel multiplication in a ceramic facing structure, have been combined in a cold cathode for rf guns and diode guns. Electrodynamic and space-charge flow simulations were conducted to specify the cathode configuration and range of emission current density from the field emission cold cathode. Design of this cathode has been made for installation and testing in an existing S-band 2-1/2 cell rf gun. With emission control and modulation, and with current density in the range of 0.1-1 kA/cm2, this cathode could provide performance and long-life not enjoyed by other currently-available cathodes

  4. Advanced power flow technologies for high current ICF accelerators

    International Nuclear Information System (INIS)

    VanDevender, J.P.; McDaniel, D.H.

    1978-01-01

    Two new technologies for raising the power density in high current, inertial confinement fusion accelerators have been developed in the past two years. Magnetic flashover inhibition utilizes the self-magnetic fields around the vacuum insulator surface to inhibit surface flashover; average electric fields of 40 Mv/m at magnetic fields of 1.1 T have been achieved. Self-magnetic insulation of long, vacuum transmission lines has been used to transport power at 1.6 x 10 14 W/m 2 over six meters and up to 1.6 x 10 15 W/m 2 over short distances in a radial anode-cathode feed. The recent data relevant to these new technologies and their implications for ICF will be explored

  5. Survey of Digital Feedback Systems in High Current Storage Rings

    International Nuclear Information System (INIS)

    Teytelman, Dmitry

    2003-01-01

    In the last decade demand for brightness in synchrotron light sources and luminosity in circular colliders led to construction of multiple high current storage rings. Many of these new machines require feedback systems to achieve design stored beam currents. In the same time frame the rapid advances in the technology of digital signal processing allowed the implementation of these complex feedback systems. In this paper I concentrate on three applications of feedback to storage rings: orbit control in light sources, coupled-bunch instability control, and low-level RF control. Each of these applications is challenging in areas of processing bandwidth, algorithm complexity, and control of time-varying beam and system dynamics. I will review existing implementations as well as comment on promising future directions

  6. High current superconductors for tokamak toroidal field coils

    International Nuclear Information System (INIS)

    Fietz, W.A.

    1976-01-01

    Conductors rated at 10,000 A for 8 T and 4.2 K are being purchased for the first large coil segment tests at ORNL. Requirements for these conductors, in addition to the high current rating, are low pulse losses, cryostatic stability, and acceptable mechanical properties. The conductors are required to have losses less than 0.4 W/m under pulsed fields of 0.5 T with a rise time of 1 sec in an ambient 8-T field. Methods of calculating these losses and techniques for verifying the performance by direct measurement are discussed. Conductors stabilized by two different cooling methods, pool boiling and forced helium flow, have been proposed. Analysis of these conductors is presented and a proposed definition and test of stability is discussed. Mechanical property requirements, tensile and compressive, are defined and test methods are discussed

  7. High pressure, high current, low inductance, high reliability sealed terminals

    Science.gov (United States)

    Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN

    2010-03-23

    The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

  8. Highly efficient red electrophosphorescent devices at high current densities

    International Nuclear Information System (INIS)

    Wu Youzhi; Zhu Wenqing; Zheng Xinyou; Sun, Runguang; Jiang Xueyin; Zhang Zhilin; Xu Shaohong

    2007-01-01

    Efficiency decrease at high current densities in red electrophosphorescent devices is drastically restrained compared with that from conventional electrophosphorescent devices by using bis(2-methyl-8-quinolinato)4-phenylphenolate aluminum (BAlq) as a hole and exciton blocker. Ir complex, bis(2-(2'-benzo[4,5-α]thienyl) pyridinato-N,C 3' ) iridium (acetyl-acetonate) is used as an emitter, maximum external quantum efficiency (QE) of 7.0% and luminance of 10000cd/m 2 are obtained. The QE is still as high as 4.1% at higher current density J=100mA/cm 2 . CIE-1931 co-ordinates are 0.672, 0.321. A carrier trapping mechanism is revealed to dominate in the process of electroluminescence

  9. Continuous microwave flow synthesis of mesoporous hydroxyapatite.

    Science.gov (United States)

    Akram, Muhammad; Alshemary, Ammar Z; Goh, Yi-Fan; Wan Ibrahim, Wan Aini; Lintang, Hendrik O; Hussain, Rafaqat

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca(2+) ion released in SBF solution. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. LTS and HTS high current conductor development for DEMO

    International Nuclear Information System (INIS)

    Bruzzone, Pierluigi; Sedlak, Kamil; Uglietti, Davide; Bykovsky, Nikolay; Muzzi, Luigi; De Marzi, Gainluca; Celentano, Giuseppe; Della Corte, Antonio; Turtù, Simonetta; Seri, Massimo

    2015-01-01

    Highlights: • Design and R&D for DEMO TF conductors. • Wind&react vs. react&wind options for Nb_3Sn high grade TF conductors. • Progress in the manufacture of short length Nb_3Sn proptotypes. • Design and prototype manufacture for high current HTS cabled conductors. - Abstract: The large size of the magnets for DEMO calls for very large operating current in the forced flow conductor. A plain extrapolation from the superconductors in use for ITER is not adequate to fulfill the technical and cost requirements. The proposed DEMO TF magnets is a graded winding using both Nb_3Sn and NbTi conductors, with operating current of 82 kA @ 13.6 T peak field. Two Nb_3Sn prototypes are being built in 2014 reflecting the two approaches suggested by CRPP (react&wind method) and ENEA (wind&react method). The Nb_3Sn strand (overall 200 kg) has been procured at technical specification similar to ITER. Both the Nb_3Sn strand and the high RRR, Cr plated copper wire (400 kg) have been delivered. The cabling trials are carried out at TRATOS Cavi using equipment relevant for long length production. The completion of the manufacture of the two 20 m long prototypes is expected in the end of 2014 and their test is planned in 2015 at CRPP. In the scope of a long term technology development, high current HTS conductors are built at CRPP and ENEA. A DEMO-class prototype conductor is developed and assembled at CRPP: it is a flat cable composed of 20 twisted stacks of coated conductor tape soldered into copper shells. The 10 kA conductor developed at ENEA consists of stacks of coated conductor tape inserted into a slotted and twisted Al core, with a central cooling channel. Samples have been manufactured in industrial environment and the scalability of the process to long production lengths has been proven.

  11. Method of making a long life high current density cathode from tungsten and iridium powders using a quaternary compound as the impregnant

    International Nuclear Information System (INIS)

    Branovich, L.E.; Smith, B.; Freemen, G.L.; Eckart, D.W.

    1990-01-01

    This patent describes a method of making a long life high current density cathode. It is suitable for operation in microwave devices. It is made from tungsten and iridium powders using a quaternary compound including barium, oxygen, a metal selected from the group consisting of osmium, iridium, rhodium, and rhenium, and a metal selected from the group consisting of strontium, calcium, scandium, and titanium as the impregnant

  12. High-current relativistic klystron amplifier development for microsecond pulse lengths

    International Nuclear Information System (INIS)

    Fazio, M.V.; Carlsten, B.E.; Faehl, R.J.; Kwan, T.J.; Rickel, D.G.; Stringfield, R.M.; Tallerico, P.J.

    1991-01-01

    Los Alamos is extending the performance of the Friedman-type, high-current relativistic klystron amplifier (RKA) to the microsecond regime while attempting to achieve the gigawatt-level peak power capability that has been characteristic of the RKA at shorter pulse lengths. Currently the electron beam power into the device is about 1 GW in microsecond duration pulses, with an effort underway to increase the beam power to 2.5 GW. To date the device has yielded an rf modulated electron beam power of 350 MW, with up to 50 MW coupled into waveguide. Several aspects of RKA operation under investigation that affect RKA beam bunching efficiency and amplifier gain include cavity tuning, beam diameter, beam current, and input rf drive power, and the development of an output coupler that efficiently couples the microwave power from the low impedance beam into rectangular waveguide operating in the dominant mode. Current results from experimental testing and code modelling are presented. 5 refs., 5 figs

  13. Pyrolysis of methane by microwaves. Pt. 1

    International Nuclear Information System (INIS)

    Avni, R.; Winefordner, J.D.; Nickel, H.

    1975-04-01

    The pyrolysis of methane and mixtures of argon-methane by microwaves (2,450 MHz) was investigated. The microwave plasma diagnostic study was performed using electrical probes, namely, the double floating probe technique. Parameters such as electric field strength and current densities were measured and from their relationship the electron temperature, electric conductivity, electron and ion densities were evaluated as function of gas pressure, microwave power input and distance of the probe from the microwave cavity. Various spectroscopic techniques were used for the measurement of temperatures in the microwave plasma; the 'reversal temperature' by measuring the intensities of the electronic vibrational bands of CN and OH molecules and 'rotational temperature' from the measured intensities of rotational OH lines. The 'rotational' as well as the 'reversal temperature' were found to be identical and this temperature was assumed to be the temperature of the gas in the microwave plasma. Energy balance calculation, based upon the electrical energy input and thermal losses, were performed in order to determine if steady state conditions existed in the microwave plasma. Emission and absorption spectroscopy were used for determining the active species formed in the pyrolysis of methane and also of mixtures of CH 4 -Ar, by the microwave plasma. (orig.) [de

  14. Synthesis and electrochemical performance of Sn-doped Li3V2(PO4)3/C cathode material for lithium ion battery by microwave solid-state technique

    International Nuclear Information System (INIS)

    Liu, Haiping; Bi, Sifu; Wen, Guangwu; Teng, Xiangguo; Gao, Peng; Ni, Zujun; Zhu, Yongming; Zhang, Fang

    2012-01-01

    Highlights: ► Li 3 V 2−x Sn x (PO 4 ) 3 /C (0 ⩽ x ⩽ 0.10) cathode is first reported. ► Sn doping improves the initial discharge capacity and the cycle stability of Li 3 V 2 (PO 4 ) 3 /C. ► Sn doping improves the conductivity and reversibility of the Li 3 V 2 (PO 4 ) 3 /C. - Abstract: Li 3 V 2−x Sn x (PO 4 ) 3 /C cathode materials with uniform and fine particle sizes were successfully and fast synthesized by a microwave solid-state synthesis method. X-ray diffraction patterns demonstrated that the appropriate addition of Sn did not destroy the lattice structure of Li 3 V 2 (PO 4 ) 3 /C, but decreased the unit cell volume. X-ray photoelectron spectroscopy analysis demonstrated that the main chemical state of V in the Li 3 V 1.95 Sn 0.05 (PO 4 ) 3 /C composite is +3 valence, while the chemical state of Sn in the Li 3 V 1.95 Sn 0.05 (PO 4 ) 3 /C is +4 valence. Scanning electron microscope analysis illustrated that the addition of Sn slightly affected the morphology of samples. As the cathode materials for Li-ion batteries, Li 3 V 2−x Sn x (PO 4 ) 3 /C (x ⩽ 0.10) exhibited higher discharge capacity and better cycle stability than the pure one. At a discharge rate of 0.5 C in the potential range of 2.5–4.5 V at room temperature, the initial discharge capacity of Li 3 V 1.95 Sn 0.05 (PO 4 ) 3 /C was 136 mA h/g. The low charge-transfer resistances and large lithium ion diffusion coefficients confirmed that Sn-doped Li 3 V 2 (PO 4 ) 3 /C samples possessed better electronic conductivity and lithium ion mobility. These improved electrochemical performances can be attributed to the appropriate amount of Sn doping in Li 3 V 2 (PO 4 ) 3 /C system by enhancing structural stability and electrical conductivity. The present study also demonstrates that the microwave processing is a fast, simple and useful method for the fabrication of Li 3 V 2 (PO 4 ) 3 /C crystals.

  15. Ultra fast shutter driven by pulsed high current

    International Nuclear Information System (INIS)

    Zeng Jiangtao; Sun Fengju; Qiu Aici; Yin Jiahui; Guo Jianming; Chen Yulan

    2005-01-01

    Radiation simulation utilizing plasma radiation sources (PRS) generates a large number of undesirable debris, which may damage the expensive diagnosing detectors. An ultra fast shutter (UFS) driven by pulsed high current can erect a physical barrier to the slowly moving debris after allowing the passage of X-ray photons. The UFS consists of a pair of thin metal foils twisting the parallel axes in a Nylon cassette, compressed with an outer magnetic field, generated from a fast capacitor bank, discharging into a single turn loop. A typical capacitor bank is of 7.5 μF charging voltages varying from 30 kV to 45 kV, with corresponding currents of approximately 90 kA to 140 kA and discharging current periods of approximately 13.1 μs. A shutter closing time as fast as 38 microseconds has been obtained with an aluminium foil thickness of 100 micrometers and a cross-sectional area of 15 mm by 20 mm. The design, construction and the expressions of the valve-closing time of the UFS are presented along with the measured results of valve-closing velocities. (authors)

  16. MHD Modeling of Conductors at Ultra-High Current Density

    International Nuclear Information System (INIS)

    ROSENTHAL, STEPHEN E.; DESJARLAIS, MICHAEL P.; SPIELMAN, RICK B.; STYGAR, WILLIAM A.; ASAY, JAMES R.; DOUGLAS, M.R.; HALL, C.A.; FRESE, M.H.; MORSE, R.L.; REISMAN, D.B.

    2000-01-01

    In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator, the authors have revisited a problem first described in detail by Heinz Knoepfel. Unlike the 1-Tesla MITLs of pulsed power accelerators used to produce intense particle beams, Z's disc transmission line (downstream of the current addition) is in a 100--1,200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 they have been investigating the conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are (1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into the MHD computations. Certain features are strongly dependent on the details of the conductivity model

  17. The free recovery of a short duration, high current discharge

    International Nuclear Information System (INIS)

    Piejak, R.

    1984-01-01

    The hold-off voltage between stainless steel electrodes has been measured as a function of time after an initial discharge. The hold-off voltage is the highest voltage that the gap will withstand without appreciable current flow. A high current (600-1200 amp), short duration (170 nsec) discharge was initiated between Rogowski profile electrodes. After a pre-determined time delay, a second pulse was applied to the discharge gap. The hold-off voltage as a function to time was determined up to the Paschen breakdown voltage. Background gas pressure between 30 and 100 torr and electrode separation of 2mm and 4mm were employed. UV preionization was introduced in some tests to create various discharge modes (glow/arc). The findings indicate significantly higher recovery rates in air than in N 2 , presumably due to attachment processes. In addition, the presence of pre-breakdown UV was found to influence the discharge mode, thus affecting the recovery rate of the gap. Hold-off voltage curves for the previously mentioned gases, background pressures and electrode spacing will be presented along with open shutter photographs of the various discharge modes

  18. A high current, short pulse electron source for wakefield accelerators

    International Nuclear Information System (INIS)

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed

  19. Improved Turn-on Characteristics of Fast High Current Thyristors

    CERN Document Server

    Ducimetière, L; Vossenberg, Eugène B

    1999-01-01

    The beam dumping system of CERN's Large Hadron Collider (LHC) is equipped with fast solid state closing switches, designed for a hold-off voltage of 30 kV and a quasi half sine wave current of 20 kA, with 3 ms rise time, a maximum di/dt of 12 kA/ms and 2 ms fall time. The design repetition rate is 20 s. The switch is composed of ten Fast High Current Thyristors (FHCT’s), which are modified symmetric 4.5 kV GTO thyristors of WESTCODE. Recent studies aiming at improving the turn-on delay, switching speed and at decreasing the switch losses, have led to test an asymmetric not fully optimised GTO thyristor of WESTCODE and an optimised device of GEC PLESSEY Semiconductor (GPS), GB. The GPS FHCT, which gave the best results, is a non irradiated device of 64 mm diameter with a hold-off voltage of 4.5 kV like the symmetric FHCT. Tests results of the GPS FHCT show a reduction in turn-on delay of 40 % and in switching losses of almost 50 % with respect to the symmetric FHCT of WESTCODE. The GPS device can sustain an i...

  20. MHD Modeling of Conductors at Ultra-High Current Density

    International Nuclear Information System (INIS)

    Rosenthal, S.E.; Asay, J.R.; Desjarlais, M.P.; Douglas, M.R.; Frese, M.H.; Hall, C.A.; Morse, R.L.; Reisman, D.; Spielman, R.B.; Stygar, W.A.

    1999-01-01

    In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator we have revisited a problem first described in detail by Heinz Knoepfel. MITLs of previous pulsed power accelerators have been in the 1-Tesla regime. Z's disc transmission line (downstream of the current addition) is in a 100-1200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 we have been investigating conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are ( 1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into our MHD computations. Certain features are strongly dependent on the details of the conductivity model. Comparison with measurements on Z will be discussed

  1. Modeling photo-desorption in high current storage rings

    International Nuclear Information System (INIS)

    Barletta, W.A.

    1991-01-01

    High luminosity flavor factories are characterized by high fluxes of synchrotron radiation that lead to thermal management difficulties. The associated photo-desorption from the vacuum chamber walls presents an additional design challenge, providing a vacuum system suitable for maintaining acceptable beam-gas lifetimes and low background levels of scattered radiation in the detector. Achieving acceptable operating pressures (1-10 nTorr) with practical pumping schemes requires the use of materials with low photodesorption efficiency operating in a radiation environment beyond that of existing storage rings. Extrapolating the existing photo-desorption data base to the design requirements of high luminosity colliders requires a physical model of the differential cleaning in the vacuum chamber. The authors present a simple phenomenological model of photodesorption that includes effects of dose dependence and diffuse photon reflection to compute the leveling of gas loads in beamlines of high current storage rings that typify heavy flavor factories. This model is also used to estimate chamber commissioning times

  2. Structured Cable for High-Current Coils of Tokamaks

    Science.gov (United States)

    Benson, Christopher; McIntyre, Peter; Sattarov, Akhdiyor; Mann, Thomas

    2011-10-01

    The 45 kA superconducting cable for the ITER central solenoid coil has yielded questionable results in two recent tests. In both cases the cable Tc increased after cycling only a fraction of the design life, indicating degradation due to fatigue and fracture among the superconducting strands. The Accelerator Research Lab at Texas A&M University is developing a design for a Nb3Sn structured cable suitable for such tokamak coils. The superconductor is configured in 6 sub-cables, and each subcable is supported within a channel of a central support structure within a high-strength armor sheath. The structured cable addresses two issues that are thought to compromise opposition at high current. The strands are supported without cross-overs (which produce stress concentration); and armor sheath and core structure bypass stress through the coil and among subcables so that the stress within each subcable is only what is produced directly upon it. Details of the design and plans for development will be presented.

  3. Lattice Effects Due to High Currents in PEP-II

    International Nuclear Information System (INIS)

    Decker, F.-J.; Smith, H.; Turner, J.L.; SLAC

    2005-01-01

    The very high beam currents in the PEP-II B-Factory have caused many expected and unexpected effects: Synchrotron light fans move the beam pipe and cause dispersion; higher order modes cause excessive heating, e-clouds around the positron beam blow up its beam size. Here we describe an effect where the measured dispersion of the beam in the Low Energy Ring (LER) is different at high and at low beam currents. The dispersion was iteratively lowered by making anti-symmetric orbit bumps in many sextupole duplets, checking each time with a dispersion measurement where a dispersive kick is generated. This can be done parasitically during collisions. It was a surprise when checking the low current characterization data that there is a change. Subsequent high and low current measurements confirmed the effect. One source was believed to be located far away from any synchrotron radiation in the middle of a straight (PR12), away from sextupoles and skew quadrupoles and created a dispersion wave of about 70 mm at high current while at low current it is negligible

  4. A Compact Multi-Beamlets High Current Injector for HIFDrivers

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, J.W.; Bieniosek, F.M.; Grote, D.P.; Westenskow, G.A.

    2005-09-06

    Using curved electrodes in the injector, an array of converging beamlets can produce a beam with the envelope radius, convergence, and ellipticity matched to an electrostatic quadrupole (ESQ) channel. Experimental results were in good quantitative agreement with simulation and have demonstrated the feasibility of this concept. The size of a driver-scale injector system using this approach will be several times smaller than the one designed using traditional single large-aperture beams, so the success of this experiment has significant economical and technical impacts on the architecture of heavy ion fusion (HIF) drivers.

  5. Proposed use of the radio-frequency quadrupole structure to funnel high-current ion beams

    International Nuclear Information System (INIS)

    Stokes, R.H.; Minerbo, G.N.

    1985-01-01

    In this paper, we describe a new approach to funneling beams that are initially accelerated in two radio-frequency quadrupole (RFQ) accelerators. Instead of discrete optical elements, we propose to funnel within an RFQ structure, so that during the funneling process the beam is always confined by periodic transverse focusing. Beams with high space charge experience irreversible emittance growth when they emerge from a periodic focusing system. To alleviate this problem, in the proposed funneling system it should be possible to maintain the same focusing periodicity as that of the accelerators preceding the funnel. Also, instead of conventional deflection systems, we propose to use the properties of a modified RFQ structure to deflect two parallel beams toward each other and to merge them into a single final beam. 1 ref., 3 figs

  6. Microwave Plasma Chemical Vapor Deposition of Nano-Structured Sn/C Composite Thin-Film Anodes for Li-ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Cynthia; Marcinek, M.; Hardwick, L.J.; Richardson, T.J.; Song, X.; Kostecki, R.

    2008-02-01

    In this paper we report results of a novel synthesis method of thin-film composite Sn/C anodes for lithium batteries. Thin layers of graphitic carbon decorated with uniformly distributed Sn nanoparticles were synthesized from a solid organic precursor Sn(IV) tert-butoxide by a one step microwave plasma chemical vapor deposition (MPCVD). The thin-film Sn/C electrodes were electrochemically tested in lithium half cells and produced a reversible capacity of 440 and 297 mAhg{sup -1} at C/25 and 5C discharge rates, respectively. A long term cycling of the Sn/C nanocomposite anodes showed 40% capacity loss after 500 cycles at 1C rate.

  7. Synthesis of fluorescent carbon dots via microwave carbonization of citric acid in presence of tetraoctylammonium ion, and their application to cellular bioimaging

    International Nuclear Information System (INIS)

    Bhaisare, Mukesh Lavkush; Talib, Abou; Khan, M. Shahnawaz; Pandey, Sunil; Wu, Hui-Fen

    2015-01-01

    A jelly-like form of carbon dots (C-dots) was prepared by microwave-assisted synthesis from citric acid in the presence of tetraoctylammonium bromide. The effect of the concentration of tetraoctylammonium bromide was examined. The synthesized carbon dots were characterized by UV–vis, XRD, FTIR, fluorescence and HR-TEM. Fluorescence extends from 350 to 600 nm, and the corresponding excitation wavelengths range from 300 to 460 nm. Quantum yields are at around 0.11. A cytotoxicity study showed carbon dots to be cell permeable and biocompatible which renders them appropriate for imaging applications. The dots were used to image HeLa cell lines via the blue fluorescence of the dots. (author)

  8. MHz repetition rate solid-state driver for high current induction accelerators

    International Nuclear Information System (INIS)

    Brooksby, C; Caporaso, G; Goerz, D; Hanks, R; Hickman, B; Kirbie, H; Lee, B; Saethre, R.

    1999-01-01

    A research team from the Lawrence Livermore National Laboratory and Bechtel Nevada Corporation is developing an all solid-state power source for high current induction accelerators. The original power system design, developed for heavy-ion fusion accelerators, is based on the simple idea of using an array of field effect transistors to switch energy from a pre-charged capacitor bank to an induction accelerator cell. Recently, that idea has been expanded to accommodate the greater power needs of a new class of high-current electron accelerators for advanced radiography. For this purpose, we developed a 3-stage induction adder that uses over 4,000 field effect transistors to switch peak voltages of 45 kV at currents up to 4.8 kA with pulse repetition rates of up to 2 MHz. This radically advanced power system can generate a burst of five or more pulses that vary from 200 ns to 2 ampersand micro;s at a duty cycle of up to 25%. Our new source is precise, robust, flexible, and exceeds all previous drivers for induction machines by a factor of 400 in repetition rate and a factor of 1000 in duty cycle

  9. Guiding effect of bent macroscopic quartz tube for high current electron beam

    International Nuclear Information System (INIS)

    Zhang Mingwu; Chen Jing; Wu Yehong; Yang Bian; Wang Wei; Xue Yingli; Yu Deyang; Cai Xiaohong

    2012-01-01

    By using an incident electron beam with the high current and high energy, the guiding effect of the bent macroscopic quartz tube for the electron beam has been investigated. The angular distributions of outgoing electrons depending on the current and energy of incident electrons were measured. The dependences of electron transmitted fraction on energy and current of incident electrons are also shown. As the incident electron energy increasing, the electron transmitted fraction increases, but it decreases while the incident electron current increasing. The results have been compared with the present data. This work presents, the process of guiding electrons is essentially different from that of guiding highly charged ions, the guiding electron beam was caused by both elastic and inelastic collisions between electrons and inner walls of quartz tube, rather than self-organized charging effect on the surface of inner wall of quartz tube. (authors)

  10. Virtual cathode regime in nonstationary electric high-current discharge in hydrogen

    International Nuclear Information System (INIS)

    Baksht, F.G.; Borodin, V.S.; Zhuravlev, V.N.

    1988-01-01

    Virtual cathode (VC) regime in a non-stationary high-current hydrogen arch is constructed. Basic calculational characteristics of the near-the-cathode layer are presented. The calculation was conducted for a 1 cm long cathode under 2x10 4 A/cm 2 current density in pulse and 10 atm. pressure. A rectangular current pulse was considered. It is shown that VC formation is caused by electron temperature reduction in the near-the-cathode area. This results in the reduction of ion flux from plasma to the cathode surface and finally in the change of a sign of space charge and field intensity near the surface. Under the transition to VC regime only the cathode temperature and its effective work function are practically changed, while the rest of parameters remain approximately constant

  11. Degradation of Solid Oxide Electrolysis Cells Operated at High Current Densities

    DEFF Research Database (Denmark)

    Tao, Youkun; Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg

    2014-01-01

    In this work the durability of solid oxide cells for co-electrolysis of steam and carbon dioxide (45 % H2O + 45 % CO2 + 10 % H2) at high current densities was investigated. The tested cells are Ni-YSZ electrode supported, with a YSZ electrolyte and either a LSM-YSZ or LSCF-CGO oxygen electrode....... A current density of -1.5 and -2.0 A/cm2 was applied to the cell and the gas conversion was 45 % and 60 %, respectively. The cells were operated for a period of up to 700 hours. The electrochemical analysis revealed significant performance degradation for the ohmic process, oxygen ion interfacial transfer...

  12. Optimization of Superconducting Focusing Quadrupoles for the HighCurrent Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sabbi, GianLuca; Gourlay, Steve; Gung, Chen-yu; Hafalia, Ray; Lietzke, Alan; Martovetski, Nicolai; Mattafirri, Sara; Meinke, Rainer; Minervini, Joseph; Schultz, Joel; Seidl, Peter

    2005-09-16

    The Heavy Ion Fusion (HIF) program is progressing through a series of physics and technology demonstrations leading to an inertial fusion power plant. The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is exploring the physics of intense beams with high line-charge density. Superconducting focusing quadrupoles have been developed for the HCX magnetic transport studies. A baseline design was selected following several pre-series models. Optimization of the baseline design led to the development of a first prototype that achieved a conductor-limited gradient of 132 T/m in a 70 mm bore, without training, with measured field errors at the 0.1% level. Based on these results, the magnet geometry and fabrication procedures were adjusted to improve the field quality. These modifications were implemented in a second prototype. In this paper, the optimized design is presented and comparisons between the design harmonics and magnetic measurements performed on the new prototype are discussed.

  13. Vacuum Arc Ion Sources

    CERN Document Server

    Brown, I.

    2013-12-16

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

  14. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  15. Electrical and hydrodynamic characterization of a high current pulsed arc

    International Nuclear Information System (INIS)

    Sousa Martins, R; Chemartin, L; Zaepffel, C; Lalande, Ph; Soufiani, A

    2016-01-01

    High current pulsed arcs are of significant industrial interest and, aiming to reduce time and cost, there is progressively more and more need for computation tools that describe and predict the behaviour of these arcs. These simulation codes need inputs and validations by experimental databases, but accurate data is missing for this category of electric discharges. The principal lack of understanding is with respect to the transient phase of the current, which can reach thousands of amperes in a few microseconds. In this paper, we present the work realized on an experimental setup that simulates in the laboratory an arc column subjected to five levels of high pulsed current, ranging from 10 kA to 100 kA, with the last one corresponding to the standard lightning current waveform used in aircraft certification processes. This device was instrumented by high speed video cameras to assess the characteristic sizes of the arc channel and to characterize the shock wave generated by the arc expansion. The arc channel radius was measured over time during the axisymmetric phase and reached 3.2 cm. The position and velocity of the shock wave was determined during the first 140 μs. The background-oriented schlieren method was used to study the shock wave and a model for the light deflection inside the shock wave was developed. The mass density profile of the shock wave was estimated and showed good agreement with Rankine–Hugoniot relations at the wave front. Electrical measurements were also used to estimate the time-dependent resistance and conductivity of the arc for times lasting up to 50 μs. (paper)

  16. Electrical and hydrodynamic characterization of a high current pulsed arc

    Science.gov (United States)

    Sousa Martins, R.; Chemartin, L.; Zaepffel, C.; Lalande, Ph; Soufiani, A.

    2016-05-01

    High current pulsed arcs are of significant industrial interest and, aiming to reduce time and cost, there is progressively more and more need for computation tools that describe and predict the behaviour of these arcs. These simulation codes need inputs and validations by experimental databases, but accurate data is missing for this category of electric discharges. The principal lack of understanding is with respect to the transient phase of the current, which can reach thousands of amperes in a few microseconds. In this paper, we present the work realized on an experimental setup that simulates in the laboratory an arc column subjected to five levels of high pulsed current, ranging from 10 kA to 100 kA, with the last one corresponding to the standard lightning current waveform used in aircraft certification processes. This device was instrumented by high speed video cameras to assess the characteristic sizes of the arc channel and to characterize the shock wave generated by the arc expansion. The arc channel radius was measured over time during the axisymmetric phase and reached 3.2 cm. The position and velocity of the shock wave was determined during the first 140 μs. The background-oriented schlieren method was used to study the shock wave and a model for the light deflection inside the shock wave was developed. The mass density profile of the shock wave was estimated and showed good agreement with Rankine-Hugoniot relations at the wave front. Electrical measurements were also used to estimate the time-dependent resistance and conductivity of the arc for times lasting up to 50 μs.

  17. Characterization of a microwave generated plasma

    International Nuclear Information System (INIS)

    Root, D.J.; Mahoney, L.; Asmussen, J.

    1986-01-01

    Recent experiments have demonstrated a microwave ion beam source without and with static magnetic fields in inert gases and in oxygen gases. This plasma generation configuration also has uses in the areas of plasma processing such as plasma etching, plasma assisted thin flim deposition and plasma assisted oxide growth. These ion beam and plasma processing applications have provided motivation to investigate microwave discharge properties, such as electron density, electron temperature, gas temperature, degree of ionization, etc., of the microwave generated plasma over a wide range of experimental operating conditions. This paper presents the results of experimental measurements which attempt to characterize the experimental microwave discharge in the absence of a static magnetic field. Measurements from a double probe, which is located in the plasma in a zero microwave field region, are presented in argon, xenon and oxygen gases. Variations of plasma density and electron temperature versus absorbed microwave power, gas pressure (0.2 m Torr to 200 m Torr) and discharge diffusion length are presented and compared to dc positive column discharge theory

  18. Diamond like carbon coatings deposited by microwave plasma CVD ...

    Indian Academy of Sciences (India)

    WINTEC

    photoelectron spectroscopy (XPS) and spectroscopic ellipsometry techniques for estimating sp. 3. /sp. 2 ratio. ... ion beam deposition (Savvidas 1986), pulsed laser deposi- ... carrier gas (10 sccm) by passing 150 watts of microwave power.

  19. First-Row-Transition Ion Metals(II-EDTA Functionalized Magnetic Nanoparticles as Catalysts for Solvent-Free Microwave-Induced Oxidation of Alcohols

    Directory of Open Access Journals (Sweden)

    Nuno M. R. Martins

    2017-11-01

    Full Text Available A series of first-row transition-metals combined with ethylenediamine tetraacetic acid (EDTA, as metal-based N,O-chelating ligands, at the surface of ferrite magnetic nanoparticles (MNPs was prepared by a co-precipitation method. Those EDTA functionalized MNPs with general formula Fe3O4@EDTA-M2+ [M = Mn2+ (1, Fe2+ (2, Co2+ (3, Ni2+ (4, Cu2+ (5 or Zn2+ (6] were characterized by FTIR (Fourier Transform Infrared spectroscopy, powder XRD (X-ray Diffraction, SEM (Scanning Electron Microscope, EDS (Energy Dispersive Spectrometer, VSM (Vibrating Sample Magnetometer and TGA (Thermal Gravity Analysis. The application of the magnetic NPs towards the microwave-assisted oxidation of several alcohol substrates in a solvent-free medium was evaluated. The influence of reaction parameters such as temperature, time, type of oxidant, and presence of organic radicals was investigated. This study demonstrates that these MNPs can act as efficient catalysts for the conversion of alcohols to the corresponding ketones or aldehydes with high selectivity and yields up to 99% after 2 h of reaction at 110 °C using t-BuOOH as oxidant. Moreover, they have the advantage of being magnetically recoverable catalysts that can be easily recycled in following runs.

  20. Management of high current transients in the CWDD Injector 200 kV power system

    International Nuclear Information System (INIS)

    Carwardine, J.A.; Pile, G.; Zinneman, T.E.

    1993-01-01

    The injector for the Continuous Wave Deuterium Demonstrator is designed to deliver a high current CW negative deuterium ion beam at an energy of 200 keV to a Radio Frequency Quadrupole. The injector comprises a volume ion source, triode accelerator, high-power electron traps and low-energy beam transport with a single focusing solenoid. Some 75 Joules of energy are stored in stray capacitance around the high voltage system and discharged in a few microseconds following an injector breakdown. In order to limit damage to the accelerator grids, a magnetic snubber is incorporated to absorb most of the energy. Nevertheless, large current transients flow around the system as a result of an injector breakdown; these have frequently damaged power components and caused spurious behavior in many of the supporting systems. The analytical and practical approaches taken to minimize the effects of these transients are described. Injector breakdowns were simulated using an air spark gap and measurements made using standard EMC test techniques. The power circuit was modeled using an electrical simulation code; good agreement was reached between the model and measured results

  1. Microwave heating type evaporator

    International Nuclear Information System (INIS)

    Taura, Masazumi; Nishi, Akio; Morimoto, Takashi; Izumi, Jun; Tamura, Kazuo; Morooka, Akihiko.

    1987-01-01

    Purpose: To prevent evaporization stills against corrosion due to radioactive liquid wastes. Constitution: Microwaves are supplied from a microwave generator by way of a wave guide tube and through a microwave permeation window to the inside of an evaporatization still. A matching device is attached to the wave guide tube for transmitting the microwaves in order to match the impedance. When the microwaves are supplied to the inside of the evaporization still, radioactive liquid wastes supplied from a liquid feed port by way of a spray tower to the inside of the evaporization still is heated and evaporated by the induction heating of the microwaves. (Seki, T.)

  2. Pyrolysis of methane in flowing microwave plasma. Pt. 1, 2

    International Nuclear Information System (INIS)

    Carmi, U.; Inor, A.A.; Avni, R.; Nickel, H.

    1978-04-01

    The flowing microwave (2.45 G Hz) plasmas of methane and methane-argon mixtures were analyzed by the electrical double floating probe system (DFPS), along the flow stream. The measured electric variables of the microwave plasma were: current, current density, electric field strength, electron temperature, positive ion and electron concentrations. They indicate an irreversible process, of the polymerization of CH 4 and CH 4 +Ar mixtures, taking place in the plasma. The polymerization process reaches its maximum 'down stream'. after the position of the microwave cavity. The polymerization was correlated to the concentration of ions and electrons in the plasma. (orig.) [de

  3. Physico-chemical and mechanical modifications of polyethylene and polypropylene by ion implantation, micro-wave plasma, electron beam radiation and gamma ray irradiation; Modifications physico-chimiques et mecaniques du polyethylene et du polypropylene par implantation ionique, plasma micro-ondes, bombardement d`electrons et irradiation gamma

    Energy Technology Data Exchange (ETDEWEB)

    Liao, J D

    1995-03-29

    A polyolefin surface becomes wettable when treated by micro-wave plasma or low-dose nitrogen ion implantation. A short time argon plasma treatment is sufficient to obtain polarizable peroxides on a polyolefin. X-ray photoelectron spectroscopy analyses, paramagnetic electronic resonance analyses, peroxides decomposition, wettability measurements and infrared active spectra analyses have shown that oxidized structures obtained from different treatment techniques play an important role in the interpretation of surface chemical properties of the polymer. Micro-wave plasma treatment, and in particular argon plasma treatment, yields more polarizable groups than ion implantation and is interesting for grafting. Hardness and elasticity modulus, measured by nano-indentation on a polyolefin, increase with an appropriate ion implantation dose. A 1.4 x 10{sup 17} ions.cm{sup -2} dose can multiply by 15 the hardness of high molecular weight polyethylene, and by 7 the elasticity modulus for a 30 nm depth. The viscous-plastic to quasi-elastic transition is shown. The thickness of the modified layer is over 300 nm. The study of friction between a metal sphere and a polyethylene cupula shows that ion implantation in the polymer creates a reticulated hard and elastic layer which improves its mechanical properties and reduces the erosion rate. Surface treatments on polymers used as biomaterials allow to adapt the surface properties to specific applications. 107 refs., 66 figs., 19 tabs., 4 annexes.

  4. Synthesis of ammonia with microwave plasma

    International Nuclear Information System (INIS)

    Xu Wenguo; Yu Aimin; Liu Jun; Jin Qinhan

    1991-01-01

    THe synthesis of ammonia absorbed on 13X zeolite with the aid of microwave plasma is described. The ammonia molecule absorbed on 13X zeolite as ammonium ions were detected by IR spectroscopy. The results obtained show that the ammonia synthesis is facilitated by the surface reactions of NH x (x = 1, 2) radicals adsorbed on zeolite with hydrogen atoms

  5. Microwave energy transmission

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Hiroshi [Kyoto Univ. (Japan)

    1989-03-05

    Laying stress on the technological problems and effect on the environment of microwave energy transmission, recent scientific and engineering problems and related subjects are described. Because no fuel is required for the solar power generation, the power generation system can not be considered as an expensive one when the unit cost of energy is taken into consideration. Some of the important technological problems in the microwave energy transmission are accurate microwave beam control technology to receiving stations and improvement in the efficiency of transmission system. Microwave energy beam has effects on living bodies, communication, and plasma atmosphere of the earth. Microwave energy transmission using a space flyer unit is scheduled. Its objective is the development of microwave wireless transmission technology and the study of the correlation between high power microwave and ionosphere plasma. Experiments on such a small scale application as a microwave driven space ship to bring results seem also important. 12 refs., 13 figs.

  6. Advances in microwaves 7

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 7 covers the developments in the study of microwaves. The book discusses the effect of surface roughness on the propagation of the TEM mode, as well as the voltage breakdown of microwave antennas. The text also describes the theory and design considerations of single slotted-waveguide linear arrays and the techniques and theories that led to the achievement of wide bandwidths and ultralow noise temperatures for communication applications. The book will prove invaluable to microwave engineers.

  7. An RF ion source based primary ion gun for secondary ion mass spectroscopy

    International Nuclear Information System (INIS)

    Menon, Ranjini; Nabhiraj, P.Y.; Bhandari, R.K.

    2011-01-01

    In this article we present the design, development and characterization of an RF plasma based ion gun as a primary ion gun for SIMS application. RF ion sources, in particular Inductively Coupled Plasma (ICP) ion sources are superior compared to LMIS and duoplasmtron ion sources since they are filamentless, can produce ions of gaseous elements. At the same time, ICP ion sources offer high angular current density which is an important factor in producing high current in small spot size on the target. These high current microprobes improve the signal to noise ratio by three orders as compared to low current ion sources such as LMIS. In addition, the high current microprobes have higher surface and depth profiling speeds. In this article we describe a simple ion source in its very basic form, two lens optical column and characteristics of microprobe

  8. Microwave processing heats up

    Science.gov (United States)

    Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

  9. Cosmic Microwave Background Timeline

    Science.gov (United States)

    Cosmic Microwave Background Timeline 1934 : Richard Tolman shows that blackbody radiation in an will have a blackbody cosmic microwave background with temperature about 5 K 1955: Tigran Shmaonov anisotropy in the cosmic microwave background, this strongly supports the big bang model with gravitational

  10. Proceedings of microwave processing of materials 3

    International Nuclear Information System (INIS)

    Beatty, R.L.

    1992-01-01

    This book contains proceedings of the third MRS Symposium on Microwave Processing of Materials. Topics covered include: Microwave Processing Overviews, Numerical Modeling Techniques, Microwave Processing System Design, Microwave/Plasma Processing, Microwave/Materials Interactions, Microwave Processing of Ceramics, Microwave Processing of Polymers, Microwave Processing of Hazardous Wastes, Microwave NDE Techniques and Dielectric Properties and Measurements

  11. Microwave heating denitration device

    International Nuclear Information System (INIS)

    Sato, Hajime; Morisue, Tetsuo.

    1984-01-01

    Purpose: To suppress energy consumption due to a reflection of microwaves. Constitution: Microwaves are irradiated to the nitrate solution containing nuclear fuel materials, to cause denitrating reaction under heating and obtain oxides of the nuclear fuel materials. A microwave heating and evaporation can for reserving the nitrate solution is disposed slantwise relative to the horizontal plane and a microwave heating device is connected to the evaporation can, and inert gases for agitation are supplied to the solution within the can. Since the evaporation can is slanted, wasteful energy consumption due to the reflection of the microwaves can be suppressed. (Moriyama, K.)

  12. Design and development of a chopping and deflecting system for the high current injector at IUAC

    Science.gov (United States)

    Kedia, Sanjay Kumar; Mehta, R.

    2018-05-01

    The Low Energy Beam Transport (LEBT) section of the High Current Injector (HCI) incorporates a Chopping cum Deflecting System (CDS). The CDS comprises of a deflecting system and a pair of slits that will remove dark current and produce time bunched beam of 60 ns at different repetition rates of 4, 2, 1, 0.5, 0.25 and 0.125 MHz. The distinguishing feature of the design is the use of a multi-plate deflecting structure with low capacitance to optimize the electric field, which in turn results in higher efficiency in terms of achievable ion current. To maximize the effective electric field and its uniformity, the gap between the deflecting plates has been varied and a semi-circular contour has been incorporated on the deflecting plates. Due to this the electric field variation is less than ±0.5% within the plate length. The length of deflecting plates was chosen to maximize the transmission efficiency. Since the velocity of the charged particles in the LEBT section is constant, therefore the separation between two successive sets of deflecting plates has been kept constant to match the ions transient time within the gap which is nearly 32 ns. A square pulse has been chosen, instead of a sinusoidal one, to increase the transmission efficiency and to decrease the tailing effect. The loaded capacitance of the structure was kept 90% transmission efficiency with in the bunch length. Various simulation codes like Solid Works, TRACE 3D, CST MWS and homebrew Python codes were used to validate the design.

  13. Enhanced performance of high current discharges in JET produced by ICRF heating during the current rise

    International Nuclear Information System (INIS)

    Bures, M.; Bhatnagar, V.; Christiansen, J.P.

    1989-01-01

    The performance of high current discharges can be improved by applying central ICRF heating before or shortly after the onset of sawtooth activity in the plasma current rise phase. Long sawtooth-free periods have been obtained which result in a transiently-enhanced discharge performance. High T c (0) = 9-10.5 keV with peaked profile T e (0)/ e > = 3-4 were obtained giving values of N e (0)T e (0) up to 6 x 10 20 (keV m -3 ). Improvements in T i (0) and neutron production are observed. A best value of n Dd (0)T i (0)τ E = 1.65 x 10 20 (m -3 keV s) was achieved. Local transport simulation shows that the electron and ion thermal diffusivities do not differ substantially in the two cases of current-rise (CR) and flat-top (FT) heating, the performance of the central plasma region being enhanced, in the case of current-rise, entirely by the elimination of the sawtooth instability. The maximum D-D reaction rate is enhanced by a factor of 2 compared to the flat-top value. An appreciable part of the reaction rate is attributed to 2nd harmonic deuterium (2ω CD ) heating. In all current-rise discharges radiation amounts to 25-50% of total power and Ζ eff remains roughly constant. (author)

  14. Simulative research on the expansion of cathode plasma in high-current electron beam diode

    International Nuclear Information System (INIS)

    Xu Qifu; Liu Lie

    2012-01-01

    The expansion of cathode plasma has long been recognized as a limiting factor in the impedance lifetime of high-current electron beam diode. Realistic modeling of such plasma is of great necessity in order to discuss the dynamics of cathode plasma. Using the method of particle-in-cell, the expansion of cathode plasma is simulated in this paper by a scaled-down diode model. It is found that the formation of cathode plasma increases the current density in the diode. This consequently leads to the decrease of the potential at plasma front. Once the current density has been increased to a certain value, the potential at plasma front would then be equal to or lower than the plasma potential. Then the ions would move towards the anode, and the expansion of cathode plasma is thereby formed. Different factors affecting the plasma expansion velocity are discussed in this paper. It is shown that the decrease of proton genatation rate has the benefit of reducing the plasma expansion velocity.

  15. Modelling of crater formation on anode surface by high-current vacuum arcs

    Science.gov (United States)

    Tian, Yunbo; Wang, Zhenxing; Jiang, Yanjun; Ma, Hui; Liu, Zhiyuan; Geng, Yingsan; Wang, Jianhua; Nordlund, Kai; Djurabekova, Flyura

    2016-11-01

    Anode melting and crater formation significantly affect interruption of high-current vacuum arcs. The primary objective of this paper is to theoretically investigate the mechanism of anode surface crater formation, caused by the combined effect of surface heating during the vacuum arc and pressure exerted on the molten surface by ions and electrons from the arc plasma. A model of fluid flow and heat transfer in the arc anode is developed and combined with a magnetohydrodynamics model of the vacuum arc plasma. Crater formation is observed in simulation for a peak arcing current higher than 15 kA on 40 mm diam. Cu electrodes spaced 10 mm apart. The flow of liquid metal starts after 4 or 5 ms of arcing, and the maximum velocities are 0.95 m/s and 1.39 m/s for 20 kA and 25 kA arcs, respectively. This flow redistributes thermal energy, and the maximum temperature of the anode surface does not remain in the center. Moreover, the condition for the liquid droplet formation on the anode surfaces is developed. The solidification process after current zero is also analyzed. The solidification time has been found to be more than 3 ms after 25 kA arcing. The long solidification time and sharp features on crater rims induce Taylor cone formation.

  16. Plasma conditions for non-Maxwellian electron distributions in high current discharges and laser-produced plasmas

    International Nuclear Information System (INIS)

    Whitney, K.G.; Pulsifer, P.E.

    1993-01-01

    Results from the standard quasilinear theory of ion-acoustic and Langmuir plasma microturbulence are incorporated into the kinetic theory of the electron distribution function. The theory is then applied to high current discharges and laser-produced plasmas, where either the current flow or the nonlinear laser-light absorption acts, respectively, as the energy source for the microturbulence. More specifically, the theory is applied to a selenium plasma, whose charge state is determined under conditions of collisional-radiative equilibrium, and plasma conditions are found under which microturbulence strongly influences the electron kinetics. In selenium, we show that this influence extends over a wide range of plasma conditions. For ion-acoustic turbulence, a criterion is derived, analogous to one previously obtained for laser heated plasmas, that predicts when Ohmic heating dominates over electron-electron collisions. This dominance leads to the generation of electron distributions with reduced high-energy tails relative to a Maxwellian distribution of the same temperature. Ion-acoustic turbulence lowers the current requirements needed to generate these distributions. When the laser heating criterion is rederived with ion-acoustic turbulence included in the theory, a similar reduction in the laser intensity needed to produce non-Maxwellian distributions is found. Thus we show that ion-acoustic turbulence uniformly (i.e., by the same numerical factor) reduces the electrical and heat conductivities, as well as the current (squared) and laser intensity levels needed to drive the plasma into non-Maxwellian states

  17. Microwave Excitation In ECRIS plasmas

    International Nuclear Information System (INIS)

    Ciavola, G.; Celona, L.; Consoli, F.; Gammino, S.; Maimone, F.; Barbarino, S.; Catalano, R. S.; Mascali, D.; Tumino, L.

    2007-01-01

    A number of phenomena related to the electron cyclotron resonance ion sources (ECRIS) has been better understood recently by means of the improvement of comprehension of the coupling mechanism between microwave generators and ECR plasma. In particular, the two frequency heating and the frequency tuning effect, that permit a remarkable increase of the current for the highest charge states ions, can be explained in terms of modes excitation in the cylindrical cavity of the plasma chamber. Calculations based on this theoretical approach have been performed, and the major results will be presented. It will be shown that the electric field pattern completely changes for a few MHz frequency variations and the changes in ECRIS performances can be correlated to the efficiency of the power transfer between electromagnetic field and plasma

  18. Plasma relativistic microwave electronics

    International Nuclear Information System (INIS)

    Kuzelev, M.V.; Loza, O.T.; Rukhadze, A.A.; Strelkov, P.S.; Shkvarunets, A.G.

    2001-01-01

    One formulated the principles of plasma relativistic microwave electronics based on the induced Cherenkov radiation of electromagnetic waves at interaction of a relativistic electron beam with plasma. One developed the theory of plasma relativistic generators and accelerators of microwave radiation, designed and studied the prototypes of such devices. One studied theoretically the mechanisms of radiation, calculated the efficiencies and the frequency spectra of plasma relativistic microwave generators and accelerators. The theory findings are proved by the experiment: intensity of the designed sources of microwave radiation is equal to 500 μW, the frequency of microwave radiation is increased by 7 times (from 4 up to 28 GHz), the width of radiation frequency band may vary from several up to 100%. The designed sources of microwave radiation are no else compared in the electronics [ru

  19. Microwave Resonators and Filters

    Science.gov (United States)

    2015-12-22

    1 Microwave Resonators and Filters Daniel E. Oates MIT Lincoln Laboratory 244 Wood St. Lexington, MA 02478 USA Email: oates@ll.mit.edu...explained in other chapters, the surface resistance of superconductors at microwave frequencies can be as much as three orders of magnitude lower than the...resonators and filters in the first edition of this handbook (Z.-Y. Shen 2003) discussed the then state of the art of microwave frequency applications

  20. Microwave and RF engineering

    CERN Document Server

    Sorrentino, Roberto

    2010-01-01

    An essential text for both students and professionals, combining detailed theory with clear practical guidance This outstanding book explores a large spectrum of topics within microwave and radio frequency (RF) engineering, encompassing electromagnetic theory, microwave circuits and components. It provides thorough descriptions of the most common microwave test instruments and advises on semiconductor device modelling. With examples taken from the authors' own experience, this book also covers:network and signal theory;electronic technology with guided electromagnetic pr

  1. Use of microwave remote sensing in salinity estimation

    International Nuclear Information System (INIS)

    Singh, R.P.; Kumar, V.; Srivastav, S.K.

    1990-01-01

    Soil-moisture interaction and the consequent liberation of ions causes the salinity of waters. The salinity of river, lake, ocean and ground water changes due to seepage and surface runoff. We have studied the feasibility of using microwave remote sensing for the estimation of salinity by carrying out numerical calculations to study the microwave remote sensing responses of various models representative of river, lake and ocean water. The results show the dependence of microwave remote sensing responses on the salinity and surface temperature of water. The results presented in this paper will be useful in the selection of microwave sensor parameters and in the accurate estimation of salinity from microwave remote sensing data

  2. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Laboratory, TN (United States)

    1995-05-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymer composites. The variable frequency microwave furnace, whose initial conception and design was funded by the AIC Materials Program, will allow us, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of thermoset resins will be studied because it hold the potential of in-situ curing of continuous-fiber composites for strong, lightweight components. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  3. Advances in microwaves 3

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 3 covers the advances and applications of microwave signal transmission and Gunn devices. This volume contains six chapters and begins with descriptions of ground-station antennas for space communications. The succeeding chapters deal with beam waveguides, which offer interesting possibilities for transmitting microwave energy, as well as with parallel or tubular beams from antenna apertures. A chapter discusses the electron transfer mechanism and the velocity-field characteristics, with a particular emphasis on the microwave properties of Gunn oscillators. The l

  4. The microwave market

    International Nuclear Information System (INIS)

    Bybokas, J.

    1989-01-01

    As superconductors move from the laboratory to the marketplace, it becomes more important for researchers and manufacturers to understand the markets for this technology. The large market for microwave systems represents a major opportunity for high-T c superconductors. Conductor losses are a primary design limitation in conventional microwave systems. The low losses of superconductors at microwave frequencies will allow component designers and system designers to improve their products in many ways. The most important market segments for microwave systems are outlined in this discussion

  5. MICROWAVE INTERACTIONS WITH INHOMOGENEOUS PARTIALLY IONIZED PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Kritz, A. H.

    1962-11-15

    Microwave interactions with inhomogeneous plasmas are often studied by employing a simplified electromagnetic approach, i.e., by representing the effects of the plasma by an effective dielectric coefficient. The problems and approximations associated with this procedure are discussed. The equation describing the microwave field in an inhomogeneous partially ionized plasma is derived, and the method that is applied to obtain the reflected, transmitted, and absorbed intensities in inhomogeneous plasmas is presented. The interactions of microwaves with plasmas having Gaussian electron density profiles are considered. The variation of collision frequency with position is usually neglected. In general, the assumption of constant collision frequency is not justified; e.g., for a highly ionized plasma, the electron density profile determines, in part, the profile of the electron-ion collision frequency. The effect of the variation of the collision frequency profile on the interaction of microwaves with inhomogeneous plasmas is studied in order to obtain an estimate of the degree of error that may result when constant collision frequency is assumed instead of a more realistic collision frequency profile. It is shown that the degree of error is of particular importance when microwave analysis is used as a plasma diagnostic. (auth)

  6. Transport of long-pulse relativistic electron beams in preformed plasma channels in the ion focus regime

    International Nuclear Information System (INIS)

    Miller, J.D.

    1989-01-01

    Experiments have been performed demonstrating efficient transport of long-pulse (380 ns), high-current (200 A), relativistic electron beams (REBs) in preformed plasma channels in the ion focus regime (IFR). Plasma channels were created by low-energy ( e , and channel ion mass, in agreement with theoretical values predicted for the ion hose instability. Microwave emission has also been observed indicative of REB-plasma electron two-stream instability. Plasma channel density measurements indicate that the two-stream instability can become dominant for measured f e values slightly above unity. The author has introduced a theoretical analysis for high-current REB transport and modulation in axially periodic IFR plasma channels. Analytic expression for the electric field are found for the case of a cosine modulation of the channel ion density. Two different types of channels are considered: (i) periodic beam-induced ionization channels, and (ii) periodic plasma slab channels created by an external source. Analytical conditions are derived for the matched radius of the electron beam and for approximate beam envelope motion using a 'smooth' approximation. Numerical solutions to the envelope equation show that by changing the wavelength or the amplitude of the space-charge neutralization fraction of the ion channel density modulation, the beam can be made to focus and diverge, or to undergo stable, modulated transport

  7. Beam-plasma instability in charged plasma in the absence of ions

    Energy Technology Data Exchange (ETDEWEB)

    Dubinov, Alexander E. [National Research Nuclear University “MEPhI,” Kashirskoe Highway, 31, Moscow 115409, Russia and Sarov State Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Dukhova Str., 6, Sarov, Nizhni Novgorod Region 607186 (Russian Federation); Petrik, Alexey G. [Saratov State Technical University, Politechnicheskaja 77, Saratov 410028 (Russian Federation); Kurkin, Semen A.; Frolov, Nikita S.; Koronovskii, Alexey A.; Hramov, Alexander E., E-mail: hramovae@gmail.com [Saratov State Technical University, Politechnicheskaja 77, Saratov 410028 (Russian Federation); Saratov State University, Astrakhanskaja 83, Saratov 410012 (Russian Federation)

    2016-04-15

    We report on the possibility of the beam-plasma instability development in the system with electron beam interacting with the single-component hot electron plasma without ions. As considered system, we analyse the interaction of the low-current relativistic electron beam (REB) with squeezed state in the high-current REB formed in the relativistic magnetically insulated two-section vircator drift space. The numerical analysis is provided by means of 3D electromagnetic simulation in CST Particle Studio. We have conducted an extensive study of characteristic regimes of REB dynamics determined by the beam-plasma instability development in the absence of ions. As a result, the dependencies of instability increment and wavelength on the REB current value have been obtained. The considered process brings the new mechanism of controlled microwave amplification and generation to the device with a virtual cathode. This mechanism is similar to the action of the beam-plasma amplifiers and oscillators.

  8. Microwave simulation of laser plasma interactions. Final report

    International Nuclear Information System (INIS)

    1977-01-01

    Various electron and ion current, electric field, and magnetic field probes were developed and tested during the course of the investigation. A three dimensional probe drive system was constructed in order to investigate two and three dimensional phenomena occurring in the microwave plasma interaction. In most of the experiments reported here, a 1 GHz, 40 kilowatt, pulsed rf source (Applied Microwave), was used. The antenna was a 20 0 horn. A dipole fed parabolic antenna system capable of producing a focussed microwave beam at 2.3 GHz was developed and bench tested. This system will be used in future investigations at higher power levels

  9. Microwave Enhanced Reactive Distillation

    NARCIS (Netherlands)

    Altman, E.

    2011-01-01

    The application of electromagnetic irradiation in form of microwaves (MW) has gathered the attention of the scientific community in recent years. MW used as an alternative energy source for chemical syntheses (microwave chemistry) can provide clear advantages over conventional heating methods in

  10. Integrated microwave photonics

    NARCIS (Netherlands)

    Marpaung, D.A.I.; Roeloffzen, C.G.H.; Heideman, Rene; Leinse, Arne; Sales, S.; Capmany, J.

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A

  11. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between...... various requirements to be fulfilled in the design of an imaging system for breast cancer detection and some strategies to overcome these limitations....

  12. MICROWAVES IN ORGANIC SYNTHESIS

    Science.gov (United States)

    The effect of microwaves, a non-ionizing radiation, on organic reactions is described both in polar solvents and under solvent-free conditions. The special applications are highlighted in the context of solventless organic synthesis which involve microwave (MW) exposure of neat r...

  13. Variable frequency microwave heating apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Bible, D.W.; Lauf, R.J.; Johnson, A.C.; Thigpen, L.T.

    1999-10-05

    A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

  14. Pulsed vapor source for use in ion sources for heavy-ion accelerators

    International Nuclear Information System (INIS)

    Shiloh, J.; Chupp, W.; Faltens, A.; Keefe, D.; Kim, C.; Rosenblum, S.; Tiefenback, M.

    1980-01-01

    A pulsed cesium vapor source for use in ion sources for high-current heavy-ion accelerators is described. The source employs a vacuum spark in Cs and its properties are measured with a hot-filament Cs detector

  15. Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

    International Nuclear Information System (INIS)

    Lu, Xiaolong; Wang, Junrun; Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng; Qian, Xiangping; Xu, Dapeng; Lan, Changlin; Yao, Zeen

    2016-01-01

    An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft–Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

  16. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  17. Gold Nanoparticle Microwave Synthesis

    International Nuclear Information System (INIS)

    Krantz, Kelsie E.; Christian, Jonathan H.; Coopersmith, Kaitlin; Washington II, Aaron L.; Murph, Simona H.

    2016-01-01

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  18. Intense microwave pulses II. SPIE Volume 2154

    International Nuclear Information System (INIS)

    Brandt, H.E.

    1994-01-01

    The primary purpose of this conference was to present and critically evaluate new and ongoing research on the generation and transmission of intense microwave pulses. Significant progress was reported on high-power, high-current relativistic klystron amplifier research and design. Other work presented at the conference, include research on a high-power relativistic magnetron driven by a high-current linear induction accelerator, derivation of a Pierce-type dispersion relation describing the interaction of an intense relativistic electron beam with a corrugated cylindrical slow-wave structure, experiments on an X-band backward-wave cyclotron maser oscillator, and observation of frequency chirping in a free electron laser amplifier. Other presentations included work on multiwave Cerenkov generator experiments, analysis of resonance characteristics of slow-wave structures in high-power Cerenkov devices, linear analysis and numerical simulation of Doppler-shifted cyclotron harmonics in a cyclotron autoresonance klystron, high-power virtual cathode oscillator theory and experiments, design of a sixth-harmonic gyrofrequency multiplier as a millimeter-wave source, and experiments on dielectric-loaded and multiwave slotted gyro-TWT amplifiers. A review was presented on innovative concepts which employ high-power microwaves in propulsion of space vehicles. Separate abstracts were prepared for 34 papers of this conference

  19. Advances in microwaves

    CERN Document Server

    Young, Leo

    1967-01-01

    Advances in Microwaves, Volume 2 focuses on the developments in microwave solid-state devices and circuits. This volume contains six chapters that also describe the design and applications of diplexers and multiplexers. The first chapter deals with the parameters of the tunnel diode, oscillators, amplifiers and frequency converter, followed by a simple physical description and the basic operating principles of the solid state devices currently capable of generating coherent microwave power, including transistors, harmonic generators, and tunnel, avalanche transit time, and diodes. The next ch

  20. Advances in microwaves 4

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 4 covers some innovations in the devices and applications of microwaves. This volume contains three chapters and begins with a discussion of the application of microwave phasers and time delay elements as beam steering elements in array radars. The next chapter provides first an overview of the technical aspects and different types of millimeter waveguides, followed by a survey of their application to railroads. The last chapter examines the general mode of conversion properties of nonuniform waveguides, such as waveguide tapers, using converted Maxwell's equatio

  1. Research of transportation efficiency of low-energy high- current electron beam in plasma channel in external magnetic field

    International Nuclear Information System (INIS)

    Vagin, E S; Grigoriev, V P

    2015-01-01

    Effective high current (5-20 kA) and low energy (tens of keV) electrons beam transportation is possible only with almost complete charging neutralization. It is also necessary to use quite high current neutralization for elimination beam self-pinching effect. The research is based on the self-consistent mathematical model that takes into account beam and plasma particles dynamic, current and charge neutralization of electron beam and examines the transportation of electron beam into a chamber with low-pressure plasma in magnetic field. A numerical study was conducted using particle in cell (PIC) method. The study was performed with various system parameters: rise time and magnitude of the beam current, gas pressure and plasma density and geometry of the system. Regularities of local virtual cathode field generated by the beam in the plasma channel, as well as ranges of parameters that let transportation beam with minimal losses, depending on the external magnetic field were determined through a series of numerical studies. In addition, the assessment of the impact of the plasma ion mobility during the transition period and during steady beam was performed. (paper)

  2. High-voltage, high-current, solid-state closing switch

    Science.gov (United States)

    Focia, Ronald Jeffrey

    2017-08-22

    A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

  3. Dynamics of a relativistic electron beam in a high-current diode with a knife-edge cathode

    International Nuclear Information System (INIS)

    Babykin, V.M.; Gordeev, A.V.; Golovin, G.T.; Korolev, V.D.; Kopchikov, A.V.; Tulupov, M.V.; Chernenko, A.S.; Shuvaev, V.Yu.

    1991-01-01

    For a number of practical applications, e.g., producing discharges in large volumes in order to pump gas lasers and for short x-ray pulses, it is necessary to generate electron beams in megamp range with electron energies from hundreds of kilovolts to several megavolts. It has been possible to obtain high currents (I ± 1 MA) by using diodes with knife-edge cathodes. Knife-edge diodes have an important advantage over the parapotential type because the ion current in them comprises a relatively small fraction of the total current. This is because the electron path in the accelerating gap of knife-edge diodes is quite short in comparison with that in high-current parapotential diodes. From the point of view of applying ribbon-shaped or narrow electron beams, the important problems are in measuring the current-voltage characteristics of the diodes and determining the dynamics of the energy spectrum and the angular spread of the electrons. The generation of an electron beam with a current ∼130 kA and pulse length ∼60 ns is studied. The current-voltage characteristics of knife-edge diodes with various geometries, the dynamics of the angular spread, and the beam structure are studied. As a result of the study of the REB dynamics it is found that the operation of the diode with these experiments can be approximated by a proposed formula which includes the finite thickness of the knife-edge cathode and the motion of the plasma and ions in the discharge gap. Breaking up of the beam into individual current-carrying channels is observed with the characteristic scale ∼1-2 mm. It is noted that for the diode geometry with a knife-edge cathode, when the magnetic field changes sign and passes through zero, an instability can exist which is analogous to the dissipative tearing instability

  4. Microwave photonics shines

    Science.gov (United States)

    Won, Rachel

    2011-12-01

    The combination of microwave photonics and optics has advanced many applications in defence, wireless communications, imaging and network infrastructure. Rachel Won talks to Jianping Yao from the University of Ottawa in Canada about the importance of this growing field.

  5. Cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Wilson, R.W.

    1979-01-01

    The 20-ft horn-reflector antenna at Bell Laboratories is discussed in detail with emphasis on the 7.35 cm radiometer. The circumstances leading to the detection of the cosmic microwave background radiation are explored

  6. Integrated Microwave Photonics

    OpenAIRE

    Marpaung, David; Roeloffzen, Chris; Heideman, René; Leinse, Arne; Sales Maicas, Salvador; Capmany Francoy, José

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A particular aspect that recently gains significant interests is the use of photonic integrated circuit (PIC) technology in the MWP field for enhanced functionalities and robustness as well as the r...

  7. Microwave system engineering principles

    CERN Document Server

    Raff, Samuel J

    1977-01-01

    Microwave System Engineering Principles focuses on the calculus, differential equations, and transforms of microwave systems. This book discusses the basic nature and principles that can be derived from thermal noise; statistical concepts and binomial distribution; incoherent signal processing; basic properties of antennas; and beam widths and useful approximations. The fundamentals of propagation; LaPlace's Equation and Transmission Line (TEM) waves; interfaces between homogeneous media; modulation, bandwidth, and noise; and communications satellites are also deliberated in this text. This bo

  8. A microwave powered sensor assembly for microwave ovens

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a microwave powered sensor assembly for micro- wave ovens. The microwave powered sensor assembly comprises a microwave antenna for generating an RF antenna signal in response to microwave radiation at a predetermined excitation frequency. A dc power supply circuit...... of the microwave powered sensor assembly is operatively coupled to the RF antenna signal for extracting energy from the RF antenna signal and produce a power supply voltage. A sensor is connected to the power supply voltage and configured to measure a physical or chemical property of a food item under heating...... in a microwave oven chamber....

  9. Measurement of population inversion for FUV transitions in Kr-like Y IV in a high-current reflex discharge

    International Nuclear Information System (INIS)

    Fournier, K.B.; Shlyaptsev, V.N.; Goldstein, W.H.; Stutman, D.; Soukhanovskii, V.; Finkenthal, M.; May, M.J.; Vero, R.

    2000-01-01

    Kr-like ions are good candidates for FUV lasing since they can be produced in plasmas quite easily. We present results from a spectroscopic investigation of Y IV emission from a high current density, cold cathode reflex discharge. The Y II to Y V emission is recorded in the 200-3000 A range using photometrically calibrated spectrometers, while the emission of trace aluminum ions serves for plasma diagnostics. The intensities of the Y IV 4d-5p and 5s7-5p transitions strongly increase relative to lines from Y II and Y III with increasing plasma current. The spectra studied here are obtained at a current density of 1.75 A/cm 2 . Experimental Y IV intensity ratios spanning several excited configurations are compared with collisional radiative predictions of the HULLAC atomic physics package. Good agreement is found for the measured and predicted ratios of 4p 5 5p to 4p 5 5s level populations per statistical weight. Finally, the response of the Kr-like system to a fast, transient excitation pulse is examined using the RADEX code. Large transient gains are predicted for several 5s-5p transitions in Kr-like Y IV. (orig.)

  10. Design of a microwave calorimeter for the microwave tokamak experiment

    International Nuclear Information System (INIS)

    Marinak, M.

    1988-01-01

    The initial design of a microwave calorimeter for the Microwave Tokamak Experiment is presented. The design is optimized to measure the refraction and absorption of millimeter rf microwaves as they traverse the toroidal plasma of the Alcator C tokamak. Techniques utilized can be adapted for use in measuring high intensity pulsed output from a microwave device in an environment of ultra high vacuum, intense fields of ionizing and non-ionizing radiation and intense magnetic fields. 16 refs

  11. Microwave instability across the transition energy

    International Nuclear Information System (INIS)

    Lee, S.Y.; Wang, J.M.

    1985-01-01

    It is well known that during the acceleration of hadrons in a storage ring, the beam always goes above the microwave instability threshold near the transition energy γ /SUB t/ . The reason is that the longitudinal revolution frequency spread of the beam which otherwise provides Landau damping vanishes at the transition energy. The amount of the beam dilution near the transition energy is determined by /tau/ /SUB th/ , the length of time when the beam stays unstable, and the growth rate of the instability. It is pointed out in this paper that /tau/ /SUB th/ is proportional to the fourth power of γ /SUB t/ , and thus the choice of a large γ /SUB t/ is not desirable from this point of view. An analysis is also given of the microwave instability induced beam dilution for the proposed Relativistic Heavy Ion Collider at BNL

  12. Microwave instability across the transition energy

    International Nuclear Information System (INIS)

    Lee, S.Y.; Wang, J.M.

    1985-01-01

    It is well known that during the acceleration of hadrons in a storage ring, the beam always goes above the microwave instability threshold near the transition energy γ/sub t/. The reason is that the longitudinal revolution frequency spread of the beam which otherwise provides Landau damping vanishes at the transition energy. The amount of the beam dilution near the transition energy is determined by tau/sub th/, the length of time when the beam stays unstable, and the growth rate of the instability. It is pointed out in this paper that tau/sub th/ is proportional to the fourth power of γ/sub t/, and thus the choice of a large γ/sub t/ is not desirable from this point of view. An analysis is also given of the microwave instability induced beam dilution for the proposed Relativistic Heavy Ion Collider at BNL

  13. Generation of Low-Energy High-Current Electron Beams in Plasma-Anode Electron Guns

    Science.gov (United States)

    Ozur, G. E.; Proskurovsky, D. I.

    2018-01-01

    This paper is a review of studies on the generation of low-energy high-current electron beams in electron guns with a plasma anode and an explosive-emission cathode. The problems related to the initiation of explosive electron emission under plasma and the formation and transport of high-current electron beams in plasma-filled systems are discussed consecutively. Considerable attention is given to the nonstationary effects that occur in the space charge layers of plasma. Emphasis is also placed on the problem of providing a uniform energy density distribution over the beam cross section, which is of critical importance in using electron beams of this type for surface treatment of materials. Examples of facilities based on low-energy high-current electron beam sources are presented and their applications in materials science and practice are discussed.

  14. Fault diagnosis and performance evaluation for high current LIA based on radial basis function neural network

    International Nuclear Information System (INIS)

    Yang Xinglin; Wang Huacen; Chen Nan; Dai Wenhua; Li Jin

    2006-01-01

    High current linear induction accelerator (LIA) is a complicated experimental physics device. It is difficult to evaluate and predict its performance. this paper presents a method which combines wavelet packet transform and radial basis function (RBF) neural network to build fault diagnosis and performance evaluation in order to improve reliability of high current LIA. The signal characteristics vectors which are extracted based on energy parameters of wavelet packet transform can well present the temporal and steady features of pulsed power signal, and reduce data dimensions effectively. The fault diagnosis system for accelerating cell and the trend classification system for the beam current based on RBF networks can perform fault diagnosis and evaluation, and provide predictive information for precise maintenance of high current LIA. (authors)

  15. Surface motion and confinement potential for a microwave confined corona

    International Nuclear Information System (INIS)

    Ensley, D.L.

    1979-07-01

    Approximate time dependent solutions for surface velocities and potentials are given for a plane polarized microwave field confining a hot, over-dense plasma corona. Steady state solutions to Poissons' equation can be applied to the time dependent case, provided transit time effects are included. The product of ion pressure and potential wave (surface) velocity gives an average heating rate approx. 7/32 NKT 0 V/sub theta/ directly to the ions

  16. A reflexing electron microwave amplifier for rf particle accelerator applications

    International Nuclear Information System (INIS)

    Fazio, M.V.; Hoeberling, R.F.

    1988-01-01

    The evolution of rf-accelerator technology toward high-power, high-current, low-emittance beams produces an ever-increasing demand for efficient, very high power microwave power sources. The present klystron technology has performed very well but is not expected to produce reliable gigawatt peak-power units in the 1- to 10-GHz regime. Further major advancements must involve other types of sources. The reflexing-electron class of sources can produce microwave powers at the gigawatt level and has demonstrated operation from 800-MHz to 40-GHz. The pulse length appears to be limited by diode closure, and reflexing-electron devices have been operated in a repetitively pulsed mode. A design is presented for a reflexing electron microwave amplifier that is frequency and phase locked. In this design, the generated microwave power can be efficiently coupled to one or several accelerator loads. Frequency and phase-locking capability may permit parallel-source operation for higher power. The low-frequency (500-MHz to 10-GHz) operation at very high power required by present and proposed microwave particle accelerators makes an amplifier, based on reflexing electron phenomena, a candidate for the development of new accelerator power sources. (author)

  17. Generation and transportation of low-energy, high-current electron beams

    International Nuclear Information System (INIS)

    Ozur, G.E.; Proskurovskij, D.I.; Nazarov, D.S.

    1996-01-01

    Experimental data on the production of low-energy, high-current electron beams in a plasma-filled diode are presented. The highest beam energy density achieved is about 40 J/cm 2 , which makes it possible to treat materials in the mode of intense evaporation of the surface layer. It was shown that the use of a hollow cathode improves the beam homogeneity. The feasibility was demonstrated of the production of low-energy high-current electron beams in a gun with plasma anode based on the use of a reflective discharge. (author). 6 figs., 6 refs

  18. The design of a five-cell high-current superconducting cavity

    International Nuclear Information System (INIS)

    Li Yongming; Zhu Feng; Quan Shengwen; Liu Kexin; Nassiri, Ali

    2012-01-01

    Energy recovery linacs are promising for achieving high average current with superior beam quality. The key component for accelerating such high-current beams is the superconducting radio-frequency cavity. The design of a 1.3 GHz five-cell high-current superconducting cavity has been carried out under cooperation between Peking University and the Argonne National Laboratory. The radio-frequency properties, damping of the higher order modes, multipacting and mechanical features of this cavity have been discussed and the final design is presented. (authors)

  19. Generation and transportation of low-energy, high-current electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Ozur, G E; Proskurovskij, D I; Nazarov, D S [Russian Academy of Sciences, Tomsk (Russian Federation). Institute of High Current Electronics

    1997-12-31

    Experimental data on the production of low-energy, high-current electron beams in a plasma-filled diode are presented. The highest beam energy density achieved is about 40 J/cm{sup 2}, which makes it possible to treat materials in the mode of intense evaporation of the surface layer. It was shown that the use of a hollow cathode improves the beam homogeneity. The feasibility was demonstrated of the production of low-energy high-current electron beams in a gun with plasma anode based on the use of a reflective discharge. (author). 6 figs., 6 refs.

  20. Method for controlling low-energy high current density electron beams

    International Nuclear Information System (INIS)

    Lee, J.N.; Oswald, R.B. Jr.

    1977-01-01

    A method and an apparatus for controlling the angle of incidence of low-energy, high current density electron beams are disclosed. The apparatus includes a current generating diode arrangement with a mesh anode for producing a drifting electron beam. An auxiliary grounded screen electrode is placed between the anode and a target for controlling the average angle of incidence of electrons in the drifting electron beam. According to the method of the present invention, movement of the auxiliary screen electrode relative to the target and the anode permits reliable and reproducible adjustment of the average angle of incidence of the electrons in low energy, high current density relativistic electron beams

  1. MICROWAVE TECHNOLOGY CHEMICAL SYNTHESIS APPLICATIONS

    Science.gov (United States)

    Microwave-accelerated chemical syntheses in various solvents as well as under solvent-free conditions have witnessed an explosive growth. The technique has found widespread application predominantly exploiting the inexpensive unmodified household microwave (MW) ovens although th...

  2. Microwave engineering concepts and fundamentals

    CERN Document Server

    Khan, Ahmad Shahid

    2014-01-01

    Detailing the active and passive aspects of microwaves, Microwave Engineering: Concepts and Fundamentals covers everything from wave propagation to reflection and refraction, guided waves, and transmission lines, providing a comprehensive understanding of the underlying principles at the core of microwave engineering. This encyclopedic text not only encompasses nearly all facets of microwave engineering, but also gives all topics—including microwave generation, measurement, and processing—equal emphasis. Packed with illustrations to aid in comprehension, the book: •Describes the mathematical theory of waveguides and ferrite devices, devoting an entire chapter to the Smith chart and its applications •Discusses different types of microwave components, antennas, tubes, transistors, diodes, and parametric devices •Examines various attributes of cavity resonators, semiconductor and RF/microwave devices, and microwave integrated circuits •Addresses scattering parameters and their properties, as well a...

  3. Parameter prediction for microwave garnets

    International Nuclear Information System (INIS)

    Ramer, R.

    1996-01-01

    Full text: Linearity of the microwave parameters (resonance linewidth ΔH and effective linewidth ΔH eff ) is demonstrated and their use in the Computer-aided design (CAD)/Computer-aided manufacturing (CAM) of new microwave garnets is proposed. Such an approach would combine a numerical database of microwave data and several computational programs. The model is an applied formulation of the analysis of a wide range of microwave garnets

  4. Ion optics of RHIC EBIS

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A.; Alessi, J.; Beebe, E.; Kponou, A.; Okamura, M.; Raparia, D.; Ritter, J.; Tan, Y.; Kuznetsov, G.

    2011-09-10

    RHIC EBIS has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.

  5. Microwave Tokamak Experiment

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The Microwave Tokamak Experiment, now under construction at the Laboratory, will use microwave heating from a free-electron laser. The intense microwave pulses will be injected into the tokamak to realize several goals, including a demonstration of the effects of localized heat deposition within magnetically confined plasma, a better understanding of energy confinement in tokamaks, and use of the new free-electron laser technology for plasma heating. The experiment, soon to be operational, provides an opportunity to study dense plasmas heated by powers unprecedented in the electron-cyclotron frequency range required by the especially high magnetic fields used with the MTX and needed for reactors. 1 references, 5 figures, 3 tables

  6. Balanced microwave filters

    CERN Document Server

    Hong, Jiasheng; Medina, Francisco; Martiacuten, Ferran

    2018-01-01

    This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including, narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 exa...

  7. High power microwaves

    CERN Document Server

    Benford, James; Schamiloglu, Edl

    2016-01-01

    Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

  8. Microwave-assisted Chemical Transformations

    Science.gov (United States)

    In recent years, there has been a considerable interest in developing sustainable chemistries utilizing green chemistry principles. Since the first published report in 1986 by Gedye and Giguere on microwave assisted synthesis in household microwave ovens, the use of microwaves as...

  9. A new matcher type between RFQ and IH-DTL for the GSI high current heavy ion prestripper linac

    International Nuclear Information System (INIS)

    Ratzinger, U.; Tiede, R.

    1996-01-01

    The adaptation of a RFQ beam to the typical requirements at the entrance of a drift tube linac is rather difficult at high intensities and high A/q values. The high focusing power needed for such a matcher can be provided by a conventional array with rather large quadrupoles and rebuncher cavities only. Many problems arising from such a design can be avoided by using an element which is focusing in transverse and longitudinal direction at the same time, that is a short RFQ ('Super Lens') with 10 cells typically and a larger aperture as compared to the main RFQ. A xy-steerer and a short quadrupole doublet with small aperture were added to gain flexibility with regard to beam mismatch and misalignment corrections. This new concept is realised for the GSI 15 mA U 4+ injector, which is under construction. Beam dynamics calculations are presented and compared with results for a conventional solution consisting of a rebuncher and a quadrupole triplet. (author)

  10. The development of shock wave overpressure driven by channel expansion of high current impulse discharge arc

    Science.gov (United States)

    Xiong, Jia-ming; Li, Lee; Dai, Hong-yu; Wu, Hai-bo; Peng, Ming-yang; Lin, Fu-chang

    2018-03-01

    During the formation of a high current impulse discharge arc, objects near the discharge arc will be strongly impacted. In this paper, a high power, high current gas switch is used as the site of the impulse discharge arc. The explosion wave theory and the arc channel energy balance equation are introduced to analyze the development of the shock wave overpressure driven by the high current impulse discharge arc, and the demarcation point of the arc channel is given, from which the energy of the arc channel is no longer converted into shock waves. Through the analysis and calculation, it is found that the magnitude of the shock wave overpressure caused by impulse discharge arc expansion is closely related to the arc current rising rate. The arc shock wave overpressure will undergo a slow decay process and then decay rapidly. The study of this paper will perform the function of deepening the understanding of the physical nature of the impulse arc discharge, which can be used to explain the damage effect of the high current impulse discharge arc.

  11. Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

    KAUST Repository

    Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Li, Lain-Jong; Huang, Kuo-Wei

    2016-01-01

    for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open

  12. Quench protection and design of large high-current-density superconducting magnets

    International Nuclear Information System (INIS)

    Green, M.A.

    1981-03-01

    Although most large superconducting magnets have been designed using the concept of cryostability, there is increased need for large magnets which operate at current densities above the cryostable limit (greater than 10 8 Am -2 ). Large high current density superconducting magnets are chosen for the following reasons: reduced mass, reduced coil thickness or size, and reduced cost. The design of large high current density, adiabatically stable, superconducting magnets requires a very different set of design rules than either large cryostable superconducting magnets or small self-protected high current density magnets. The problems associated with large high current density superconducting magnets fall into three categories; (a) quench protection, (b) stress and training, and (c) cryogenic design. The three categories must be considered simultaneously. The paper discusses quench protection and its implication for magnets of large stored energies (this includes strings of smaller magnets). Training and its relationship to quench protection and magnetic strain are discussed. Examples of magnets, built at the Lawrence Berkeley Laboratory and elsewhere using the design guidelines given in this report, are presented

  13. Measurements of picosecond pulses of a high-current electron accelerator

    International Nuclear Information System (INIS)

    Zheltov, K.A.; Petrenko, A.N.; Turundaevskaya, I.G.; Shalimanov, V.F.

    1997-01-01

    The duration of a picosecond high-current accelerator electron beam pulse duration is measured and its shape is determined using a measuring line, comprising a Faraday cup, a radiofrequency cable of minor length and a wide-band SRG-7 oscillograph. The procedure of data reconstruction according to regularization method is applied to determine the actual shape of the pulse measured

  14. Developments in the area of high-current-superconductivity in the Kernforschungszentrum Karlsruhe

    International Nuclear Information System (INIS)

    Maurer, W.; Arendt, F.; Bruenner, N.; Erb, J.; Fessler, N.; Hartwig, G.; Heinz, W.; Hofmann, A.; Juengst, K.P.; Katheder, H.

    1976-05-01

    In this report the development work is presented which has been done from 1971 to 1975 on High-Current-Superconducticity at the institute IEKP III. The report deals with the development, construction and operation of superconducting magnets, with material investigations and with the pursued applications of superconducting Magnettechnology in research and industry. (orig.) [de

  15. The high current test facility injector operation to 40 mA dc

    International Nuclear Information System (INIS)

    Ungrin, J.; Ormrod, J.H.; Michel, W.L.

    1976-01-01

    The high current test facility injector is a 750 keV proton accelerator designed to investigate the problems involved in the acceleration of intense dc proton beams. The performance of the injector and the experience gained in operation with dc beams up to 40 mA are described. (author)

  16. Reducing AC-Winding Losses in High-Current High-Power Inductors

    DEFF Research Database (Denmark)

    Nymand, Morten; Madawala, Udaya K.; Andersen, Michael Andreas E.

    2009-01-01

    Foil windings are preferable in high-current high-power inductors to realize compact designs and to reduce dc-current losses. At high frequency, however, proximity effect will cause very significant increase in ac resistance in multi-layer windings, and lead to high ac winding losses. This paper ...

  17. Application of parallel connected power-MOSFET elements to high current d.c. power supply

    International Nuclear Information System (INIS)

    Matsukawa, Tatsuya; Shioyama, Masanori; Shimada, Katsuhiro; Takaku, Taku; Neumeyer, Charles; Tsuji-Iio, Shunji; Shimada, Ryuichi

    2001-01-01

    The low aspect ratio spherical torus (ST), which has single turn toroidal field coil, requires the extremely high d.c. current like as 20 MA to energize the coil. Considering the ratings of such extremely high current and low voltage, power-MOSFET element is employed as the switching device for the a.c./d.c. converter of power supply. One of the advantages of power-MOSFET element is low on-state resistance, which is to meet the high current and low voltage operation. Recently, the capacity of power-MOSFET element has been increased and its on-state resistance has been decreased, so that the possibility of construction of high current and low voltage a.c./d.c. converter with parallel connected power-MOSFET elements has been growing. With the aim of developing the high current d.c. power supply using power-MOSFET, the basic characteristics of parallel operation with power-MOSFET elements are experimentally investigated. And, the synchronous rectifier type and the bi-directional self commutated type a.c./d.c. converters using parallel connected power-MOSFET elements are proposed

  18. Conceptual design of a high current ISOL target area at TRIUMF

    International Nuclear Information System (INIS)

    Beveridge, J.L.; Buchmann, L.; Clark, G.S.; Sprenger, H.; Thorson, I.; Vincent, J.; D'Auria, J.M.; Dombsky, M.

    1993-05-01

    Two similar conceptual designs for the handling of highly activated components at the target area of a high current radioactive beam facility have been investigated. The proposed designs are sufficiently flexible that practical detailed designs could be realized. Personnel exposure to radiation during the handling procedures is expected to be minimal. (author) 3 refs., 4 figs

  19. Microwave Assisted Drug Delivery

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    In this work, the microwave radiation is adopted for remote activation of pharmaceutical drug capsules inside the human body in order to release drugs at a pre-determined time and location. An array of controllable transmitting sources is used to produce a constructive interference at a certain...... focus point inside the body, where the drugs are then released from the specially designed capsules. An experimental setup for microwave activation has been developed and tested on a body phantom that emulates the human torso. A design of sensitive receiving structures for integration with a drug...

  20. EDITORIAL: Microwave Moisture Measurements

    Science.gov (United States)

    Kaatze, Udo; Kupfer, Klaus; Hübner, Christof

    2007-04-01

    Microwave moisture measurements refer to a methodology by which the water content of materials is non-invasively determined using electromagnetic fields of radio and microwave frequencies. Being the omnipresent liquid on our planet, water occurs as a component in most materials and often exercises a significant influence on their properties. Precise measurements of the water content are thus extremely useful in pure sciences, particularly in biochemistry and biophysics. They are likewise important in many agricultural, technical and industrial fields. Applications are broad and diverse, and include the quality assessment of foodstuffs, the determination of water content in paper, cardboard and textile production, the monitoring of moisture in sands, gravels, soils and constructions, as well as the measurement of water admixtures to coal and crude oil in reservoirs and in pipelines. Microwave moisture measurements and evaluations require insights in various disciplines, such as materials science, dielectrics, the physical chemistry of water, electrodynamics and microwave techniques. The cooperation of experts from the different fields of science is thus necessary for the efficient development of this complex discipline. In order to advance cooperation the Workshop on Electromagnetic Wave Interaction with Water and Moist Substances was held in 1993 in Atlanta. It initiated a series of international conferences, of which the last one was held in 2005 in Weimar. The meeting brought together 130 scientists and engineers from all over the world. This special issue presents a collection of some selected papers that were given at the event. The papers cover most topics of the conference, featuring dielectric properties of aqueous materials, electromagnetic wave interactions, measurement methods and sensors, and various applications. The special issue is dedicated to Dr Andrzej W Kraszewski, who died in July 2006 after a distinguished career of 48 years in the research of

  1. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  2. Microwave stability at transition

    International Nuclear Information System (INIS)

    Holt, J.A.; Colestock, P.L.

    1995-05-01

    The question of microwave stability at transition is revisited using a Vlasov approach retaining higher order terms in the particle dynamics near the transition energy. A dispersion relation is derived which can be solved numerically for the complex frequency in terms of the longitudinal impedance and other beam parameters. Stability near transition is examined and compared with simulation results

  3. Commercial microwave space power

    International Nuclear Information System (INIS)

    Siambis, J.; Gregorwich, W.; Walmsley, S.; Shockey, K.; Chang, K.

    1991-01-01

    This paper reports on central commercial space power, generating power via large scale solar arrays, and distributing power to satellites via docking, tethering or beamed power such as microwave or laser beams, that is being investigated as a potentially advantageous alternative to present day technology where each satellite carries its own power generating capability. The cost, size and weight for electrical power service, together with overall mission requirements and flexibility are the principal selection criteria, with the case of standard solar array panels based on the satellite, as the reference point. This paper presents and investigates a current technology design point for beamed microwave commercial space power. The design point requires that 25 kW be delivered to the user load with 30% overall system efficiency. The key elements of the design point are: An efficient rectenna at the user end; a high gain, low beam width, efficient antenna at the central space power station end, a reliable and efficient cw microwave tube. Design trades to optimize the proposed near term design point and to explore characteristics of future systems were performed. Future development for making the beamed microwave space power approach more competitive against docking and tethering are discussed

  4. Leakage of Microwave Ovens

    Science.gov (United States)

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  5. Open microwave cavities

    Czech Academy of Sciences Publication Activity Database

    Šeba, Petr; Rotter, I.; Mueller, M.; Persson, C.; Pichugin, Konstantin N.

    2001-01-01

    Roč. 9, - (2001), s. 484-487 ISSN 1386-9477 Institutional research plan: CEZ:A02/98:Z1-010-914 Keywords : microwave cavity * resonances Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.009, year: 2001

  6. New applications of microwave

    International Nuclear Information System (INIS)

    Ejiri, A.; Tanaka, K.; Kawahata, K.; Ito, Y.; Tokuzawa, T.

    2000-01-01

    Interferometry and reflectometry measure phase of the transparent or the reflected wave to derive the information on plasma density. Homodyne reflectometry for an interlock and transmissiometry for sheet plasma measurements could be another class of microwave diagnostics, which does not measure the phase. (author)

  7. Hybrid Microwave Technology

    International Nuclear Information System (INIS)

    Wicks, G.G.

    2001-01-01

    A team associated with a Federal Laboratory, academia, and industry has been actively developing new microwave technology for treatment and remediation of a variety of potentially hazardous materials for almost a decade. This collaboration has resulted in unique equipment and processes with potential applicability to many fields, including disposition of electronic circuitry and components, medical wastes, radioactive materials and recycling of used tires

  8. Microwave-assisted synthesis of palladium nanocubes and nanobars

    International Nuclear Information System (INIS)

    Yu, Yanchun; Zhao, Yanxi; Huang, Tao; Liu, Hanfan

    2010-01-01

    Microwave was employed in the shape-controlled synthesis of palladium nanoparticles. Palladium nanocubes and nanobars with a mean size of about 23.8 nm were readily synthesized with H 2 PdCl 4 as a precursor, tetraethylene glycol (TEG) as both a solvent and a reducing agent in the presence of PVP and CTAB in 80 s under microwave irradiation. The structures of the as-prepared palladium nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and ultraviolet-visible (UV-vis) absorption spectroscopy. The formation of PdBr 4 2- due to the coordination replacement of the ligand Cl - ions in PdCl 4 2- ions by Br - ions in the presence of bromide was responsible for the synthesis of Pd nanocubes and nanobars. In addition, a milder reducing power, a higher viscosity and a stronger affinity of TEG were beneficial to the larger sizes of Pd nanocubes and nanobars.

  9. Ion-Beam-Excited Electrostatic Ion Cyclotron Instability

    DEFF Research Database (Denmark)

    Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

    1977-01-01

    The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....

  10. Ion-Beam-Excited, Electrostatic, Ion Cyclotron Instability

    DEFF Research Database (Denmark)

    Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

    1977-01-01

    The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....

  11. Transfer and focusing of high current relativistic electron beams on a target

    International Nuclear Information System (INIS)

    Baranchikov, E.I.; Gordeev, A.V.; Koba, Yu.V.; Korolev, V.D.; Penkina, V.S.; Rudakov, L.I.; Smirnov, V.P.; Sukhov, A.D.; Tarumov, E.Z.; Bakshaeev, Yu.L.

    Research is being conducted at the I. V. Kurchatov Atomic Energy Institute to investigate possibilities of creating a pulsed thermonuclear reactor based on REBs; this work involves the creation of a multimodel system using vacuum lines for transferring energy and an acute angled external magnetic field for transferring electron beams to the target. A field of this configuration can be used at the same time for accumulating a ''cloud'' of relativistic protons around the target for purposes of irradiating them. This alternative solution of the problem of target irradiation, instead of focusing beams directly on it, may prove to be highly promising. Experiments are described which were conducted recently on high current electron accelerators ''URAL'', ''MS'' and others and which were directed at investigating possibilities of transferring and focusing high current REBs, as well as effective transmission of electromagnetic energy using vacuum lines at considerable distances

  12. Progress on the high-current 704 MHz superconducting RF cavity at BNL

    International Nuclear Information System (INIS)

    Xu, W.; Astefanous, C.; Belomestnykh, S.; Ben-Zvi, I.

    2012-01-01

    The 704 MHz high current superconducting cavity has been designed with consideration of both performance of fundamental mode and damping of higher order modes. A copper prototype cavity was fabricated by AES and delivered to BNL. RF measurements were carried out on this prototype cavity, including fundamental pass-band and HOM spectrum measurements, HOM studies using bead-pull setup, prototyping of antenna-type HOM couplers. The measurements show that the cavity has very good damping for the higher-order modes, which was one of the main goals for the high current cavity design. 3D cavity models were simulated with Omega3P code developed by SLAC to compare with the measurements. The paper describes the cavity design, RF measurement setups and results for the copper prototype. The progress with the niobium cavity fabrication will also be described.

  13. Study of pulse stretching in high current power supplies using multipulse techniques

    International Nuclear Information System (INIS)

    Trendler, R.C.

    1977-01-01

    Considerable interest exists at Fermilab to increase the pulse width of the Neutrino Focusing Horn to permit an increase in beam spill length from twenty (20) microseconds to one (1) millisecond. Two techniques to do this were examined: (1) a high current transformer, and (2) increased bank capacitance using the multi-power supply technique. The transformer is the most straightforward conceptually; it is, however, a complicated device requiring sizable changes to the existing horn power supply. This alternative is briefly reviewed. The second scheme involves pulsing a 20 kv 200 ka power supply to establish the required load current and then maintaining this current by the sequential pulsing of a number of low voltage high current power supplies. This alternative is discussed in detail with the results of tests performed on the Fermilab Focusing Horn System

  14. Electrodynamic wear of rails in high current density rail gun discharges

    International Nuclear Information System (INIS)

    Edwards, W.T.; Caldwell, S.G.

    1984-01-01

    Significant advances in high current, high speed power sources, has in recent years allowed rail guns to produce very high velocity (> 10 km/sec) macroscopic particles (> 1/10 grams). A continuing problem is the structural integrity of the components under these loadings and in particular, the rail wear due to the high current density plasma contacts. In this investigation a small bore rail gun (6x5 mm) was used with a 10.6 kjoule capacitor energy source to examine the modes of rail damage. The rails were constructed of 110 copper base material. These rails were used in an uncoated condition and also with plasma sprayed coatings of W and W/WC. The resulting surface wear was characterized by standard metallurgical techniques and analyzed for the various coatings

  15. A battery-powered high-current power supply for superconductors

    CERN Document Server

    Wake, M; Suda, K

    2002-01-01

    Since superconductors do not require voltages, a high-current power supply could run with low power if the voltage is sufficiently reduced. Even a battery-powered power supply could give as much as 2,000A for a superconductor. To demonstrate this hypothesis, a battery-powered 2,000A power supply was constructed. It uses an IGBT chopper and Schottky diode together with a specially arranged transformer to produce a high current with low voltage. Testing of 2,000A operation was performed for about 1.5 hr using 10 car batteries. Charging time for this operation was 8 hr. Ramping control was smooth and caused no trouble. Although the IGBT frequency ripple of 16.6 kHz was easily removed using a passive filter, spike noise remained in the output voltage. This ripple did not cause any trouble in operating a pancake-type inductive superconducting load. (author)

  16. Realisation and instrumentation of high current power station for superconducting cables testing

    International Nuclear Information System (INIS)

    Regnaud, S.

    2000-05-01

    This report deals with the designing of a high current station able to test electric properties of superconductors. This test station will be used for testing the superconducting wires of large hadron collider detectors in CERN. The high current test station will have to generate high intensity continuous current in a magnetic field of 0 to 5 tesla and in temperature conditions of 4.2 K. The length of wire samples submitted to the uniform magnetic field is 300 mm and the installation is fitted with equipment able to measure the magnetic field perpendicular to either faces of the wire. The peculiarity of this station is to use a superconducting transformer in order to generate the high current. The first part of this work recalls important notions concerning superconductivity. The second part presents the high current station by describing the superconducting transformer and the sample-holder. We have studied the designing of a transformer able to yield a secondary current whose intensity reaches 100 kA, such intensity generates powerful electromagnetic forces (566 kN/m) in case of defect, so the sample-holder has to be carefully design to bear them. The third part presents the cryogenic component of the station, the instrumentation of the sample-holder and the method used to measure secondary currents. In the last part we present the performance of a prototype transformer, this prototype is able to deliver a 22 kA secondary current for a 160 A primary current, the uncertainty on the measured value of the secondary current is about 3%

  17. Enhanced D-T supershot performance at high current using extensive lithium conditioning in TFTR

    International Nuclear Information System (INIS)

    Mansfield, D.K.; Strachan, J.D.; Bell, M.G.; Scott, S.D.; Budny, R.; Bell, R.E.; Bitter, M.; Darrow, D.S.; Fredrickson, E.; Grek, B.

    1995-05-01

    A substantial improvement in supershot fusion plasma performance has been realized by combining the enhanced confinement due to tritium fueling with the enhanced confinement due to extensive Li conditioning of the TFTR limiter. This combination has resulted in not only significantly higher global energy confinement times than had previously been obtained in high current supershots, but also the highest ratio of central fusion output power to input power observed to date

  18. Real time data acquisition system for the High Current Test Facility proton accelerator

    International Nuclear Information System (INIS)

    Langlais, C.E.; Erickson, P.D.; Caissie, L.P.

    1975-01-01

    A real time data acquisition system was developed to monitor and control the High Current Test Facility Proton Accelerator. It is a PDP-8/E computer system with virtual memory capability that is fully interrupt driven and operates under a real-time, multi-tasking executive. The application package includes mode selection to automatically modify programs and optimize operation under varying conditions. (U.S.)

  19. The charge deposition in the numerical simulation of high-current beam

    International Nuclear Information System (INIS)

    Wang Shijun

    1987-01-01

    A new method of charge deposition of high-current beam, conservation-map method, is given. THe advantages of Neil's and other various methods are adopted. The mistake of Neil's method and the limitation of other various methods is discarded. So the method is accurate without additional assumption. The method not only applies to the case of steady laminar flow but also applies to the case of steady non-laminar flow

  20. Quasistationary model of high-current relativistic electron beam. 1. Exact solution of Poisson equations

    International Nuclear Information System (INIS)

    Brenner, S.E.; Gandyl', E.M.; Podkopaev, A.P.

    1995-01-01

    The dynamics of high-current relativistic electron beam moving trough the cylindrical drift space has been modelled by the large particles, the shape of which allows to solve the Poisson equations exactly, and in such a way to avoid the linearization being usually used in those problems. The expressions for the components of own electric field of electron beam passing through the cylindrical drift space have been obtained. (author). 11 refs., 1 fig

  1. High-speed radiography and x-ray cinematography by high-current betatrons

    International Nuclear Information System (INIS)

    Akimochkin, Yu.V.; Akulov, G.V.; Leunov, F.G.; Moskalev, V.A.; Ryabukhin, V.L.

    1979-01-01

    The paper provides a description of an equipment system comprising a pair of 25 MeV high-current betatrons and an X-ray drum-type cinecamera for high-speed radiography and X-ray cinematography for use when studying dynamics of objects moving at a rate of 0.5 - 3.0 km/s as well as in X-ray cinematography of processes at a rate of up to 1 m/s. (author)

  2. The trend of the research and development for the upgrade of the high current energy system

    International Nuclear Information System (INIS)

    2010-01-01

    The high current energy technology ranges from a basic technology of the electric power field to a state-of-the-art technology and has been used extremely variously. In addition, as the energy technology advances, the expansion of applied field, such as the nuclear fusion and the exhaust thing processing, etc., requires a further upgrade of the large current technology. In this report, the trend of the research and development for the upgrade of the high current energy technology are summarized. In the following, the elemental technology including arc/plasma phenomena and the pulse power system is described in Chapter 2. In Chapter 3, the trend of the research and development for the upgrade of various equipments and devices such as the nuclear fusion development, the superconducting applications of SMES and the maglev transportation system, and the arc application of the exhaust processing for a medical waste, the radio active waste and a detrimental gas and the next generation lithography system. In Chapter 4, the analysis and the measurement technology of the arc phenomenon and the standardization of current shunt, etc are described. We hope this research report can contribute to the promotion of technical exchanges in different fields, and offer guidelines for future development in this high current energy technology. (author)

  3. Characteristics of PEMFC operating at high current density with low external humidification

    International Nuclear Information System (INIS)

    Fan, Linhao; Zhang, Guobin; Jiao, Kui

    2017-01-01

    Highlights: • PEMFC with low humidity and high current density is studied by numerical simulation. • At high current density, water production lowers external humidification requirement. • A steady anode circulation status without external humidification is demonstrated. • The corresponding detailed internal water transfer path in the PEMFC is illustrated. • Counter-flow is superior to co-flow at low anode external humidification. - Abstract: A three-dimensional multiphase numerical model for proton exchange membrane fuel cell (PEMFC) is developed to study the fuel cell performance and water transport properties with low external humidification. The results show that the sufficient external humidification is necessary to prevent the polymer electrolyte dehydration at low current density, while at high current density, the water produced in cathode CL is enough to humidify the polymer electrolyte instead of external humidification by flowing back and forth between the anode and cathode across the membrane. Furthermore, a steady anode circulation status without external humidification is demonstrated in this study, of which the detailed internal water transfer path is also illustrated. Additionally, it is also found that the water balance under the counter-flow arrangement is superior to co-flow at low anode external humidification.

  4. The high current, fast, 100ns, Linear Transformer Driver (LTD) developmental project at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Ward, Kevin S.; Long, Finis W.; Sinebryukhov, Vadim A.; Kim, Alexandre A.; Wakeland, Peter Eric; McKee, G. Randall; Woodworth, Joseph Ray; McDaniel, Dillon Heirman; Fowler, William E.; Mazarakis, Michael Gerrassimos; Porter, John Larry Jr.; Struve, Kenneth William; Stygar, William A.; LeChien, Keith R.; Matzen, Maurice Keith

    2010-01-01

    Sandia National Laboratories, Albuquerque, N.M., USA, in collaboration with the High Current Electronic Institute (HCEI), Tomsk, Russia, is developing a new paradigm in pulsed power technology: the Linear Transformer Driver (LTD) technology. This technological approach can provide very compact devices that can deliver very fast high current and high voltage pulses straight out of the cavity with out any complicated pulse forming and pulse compression network. Through multistage inductively insulated voltage adders, the output pulse, increased in voltage amplitude, can be applied directly to the load. The load may be a vacuum electron diode, a z-pinch wire array, a gas puff, a liner, an isentropic compression load (ICE) to study material behavior under very high magnetic fields, or a fusion energy (IFE) target. This is because the output pulse rise time and width can be easily tailored to the specific application needs. In this paper we briefly summarize the developmental work done in Sandia and HCEI during the last few years, and describe our new MYKONOS Sandia High Current LTD Laboratory.

  5. Development of large high current density superconducting solenoid magnets for use in high energy physics experiments

    International Nuclear Information System (INIS)

    Green, M.A.

    1977-05-01

    The development of a unique type of large superconducting solenoid magnet, characterized by very high current density windings and a two-phase helium tubular cooling system is described. The development of the magnet's conceptual design and the construction of two test solenoids are described. The successful test of the superconducting coil and its tubular cooling refrigeration system is presented. The safety, environmental and economic impacts of the test program on future developments in high energy physics are shown. Large solid angle particle detectors for colliding beam physics will analyze both charged and neutral particles. In many cases, these detectors will require neutral particles, such as gamma rays, to pass through the magnet coil with minimum interaction. The magnet coils must be as thin as possible. The use of superconducting windings allows one to minimize radiation thickness, while at the same time maximizing charged particle momentum resolution and saving substantial quantities of electrical energy. The results of the experimental measurements show that large high current density solenoid magnets can be made to operate at high stored energies. The superconducting magnet development described has a positive safety and environmental impact. The use of large high current density thin superconducting solenoids has been proposed in two high energy physics experiments to be conducted at the Stanford Linear Accelerator Center and Cornell University as a result of the successful experiments described

  6. Acceleration of a high-current single bunch in a linear accelerator

    International Nuclear Information System (INIS)

    Takeda, Seishi

    1984-01-01

    Some problems associated with the feasibility of an electron-positron linear collider with colliding energy of about 1x1 TeV are discussed. The first problem is related to the generation of high-current single bunch. A quasi-relativistic electron beam from an electron gun is injected into one bucket of the accelerating fields, in opposition to the longitudinal defocusing due to the space-charge effect. For generating a high-current single bunch, the beam bunching by means of the velocity modulation with a subharmonic prebuncher (SHPB) is indispensable. Three existing second generation single bunch electron linear accelerators (SLC, ANL and ISLR-Osaka Univ.) are briefly described. The results of the simulation of subharmonic-bunching is also reported. The second problem is associated with the physics of accelerating high-current single bunch. The longitudinal and transverse wake fields generated by a bunch-cavity interaction and the energy spread of the single bunch are analyzed and discussed. (Aoki, K.)

  7. Microwave discharge electrodeless lamps (MDEL). V. Microwave-assisted photolytic disinfection of Bacillus subtilis in simulated electroplating wash wastewaters.

    Science.gov (United States)

    Horikoshi, Satoshi; Tsuchida, Akihiro; Abe, Masahiko; Ohba, Naoki; Uchida, Masayoshi; Serpone, Nick

    2010-01-01

    This short article examines the microwave-assisted photolytic disinfection of aqueous solutions contaminated by Bacillus subtilis microorganisms using UV and vacuum-UV radiation emitted from a microwave discharge electrodeless lamp (MDEL), a device containing a Hg/Ar gas-fill that was proposed recently for use in Advanced Oxidation Processes (AOPs). Results of the disinfection are compared with those obtained from UV radiation emitted by a low-pressure electrode Hg lamp and by an excimer lamp. Also examined is the disinfection of B. subtilis aqueous media that contained Au3+ or Ni2+ ions, species often found in the treatment of electroplating wash wastewaters.

  8. Upgrade of the GSI-Unilac as a FAIR high current injector

    Energy Technology Data Exchange (ETDEWEB)

    Haehnel, Hendrik [Institut fuer Angewandte Physik, Goethe Universitaet Frankfurt (Germany)

    2016-07-01

    The existing UNIversal Linear Accelerator (UNILAC) at GSI will serve as ion and dedicated uranium ion injector for the Facility for Antiproton and Ion Research (FAIR). For nominal FAIR operation, 15 emA of Uranium 28+ at low emittances have to be injected by multiturn-injection into FAIR. To meet these requirements and to ensure reliable operation, the UNILAC will undergo a significant upgrade process. Upgrade measures concerning key accelerator components are described and a main focus is put on a replacement of the 54m Alvarez-section by a compact IH-DTL. This will open new options for future injection schemes into SIS100.

  9. Electron beam dynamics in Pasotron microwave sources

    International Nuclear Information System (INIS)

    Carmel, Y.; Shkvarunets, A.; Nusinovich, G.S.; Rodgers, J.; Bliokh, Yu.P.; Goebel, D.M.

    2003-01-01

    The Pasotron is a high efficiency (∼50%), plasma-assisted microwave generator in which the beam electrons exhibit two-dimensional motion in the slow wave structure. The electron beam propagates in the ion-focusing regime (Bennett pinch regime) because there is no applied magnetic field. Since initially only the neutral gas is present in the vacuum system and the ions in the neutralizing plasma channel are produced only due to the beam impact ionization, the beam dynamics in Pasotrons is inherently a nonstationary process, and important for efficient operation. The present paper contains results of experimental studies of stationary and nonstationary effects in the beam dynamics in Pasotrons and their theoretical interpretation

  10. Microwave superheaters for fusion

    International Nuclear Information System (INIS)

    Campbell, R.B.; Hoffman, M.A.; Logan, B.G.

    1987-01-01

    The microwave superheater uses the synchrotron radiation from a thermonuclear plasma to heat gas seeded with an alkali metal to temperatures far above the temperature of material walls. It can improve the efficiency of the Compact Fusion Advanced Rankine (CFAR) cycle described elsewhere in these proceedings. For a proof-of-principle experiment using helium, calculations show that a gas superheat ΔT of 2000 0 K is possible when the wall temperature is maintained at 1000 0 K. The concept can be scaled to reactor grade systems. Because of the need for synchrotron radiation, the microwave superheater is best suited for use with plasmas burning an advanced fuel such as D- 3 He. 5 refs

  11. Cryogenic microwave channelized receiver

    International Nuclear Information System (INIS)

    Rauscher, C.; Pond, J.M.; Tait, G.B.

    1996-01-01

    The channelized receiver being presented demonstrates the use of high temperature superconductor technology in a microwave system setting where superconductor, microwave-monolithic-integrated-circuit, and hybrid-integrated-circuit components are united in one package and cooled to liquid-nitrogen temperatures. The receiver consists of a superconducting X-band four-channel demultiplexer with 100-MHz-wide channels, four commercial monolithically integrated mixers, and four custom-designed hybrid-circuit detectors containing heterostructure ramp diodes. The composite receiver unit has been integrated into the payload of the second-phase NRL high temperature superconductor space experiment (HTSSE-II). Prior to payload assembly, the response characteristics of the receiver were measured as functions of frequency, temperature, and drive levels. The article describes the circuitry, discusses the key issues related to design and implementation, and summarizes the experimental results

  12. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  13. Microwave solidification project overview

    Energy Technology Data Exchange (ETDEWEB)

    Sprenger, G.

    1993-01-01

    The Rocky Flats Plant Microwave Solidification Project has application potential to the Mixed Waste Treatment Project and the The Mixed Waste Integrated Program. The technical areas being addressed include (1) waste destruction and stabilization; (2) final waste form; and (3) front-end waste handling and feed preparation. This document covers need for such a program; technology description; significance; regulatory requirements; and accomplishments to date. A list of significant reports published under this project is included.

  14. Microwave solidification project overview

    International Nuclear Information System (INIS)

    Sprenger, G.

    1993-01-01

    The Rocky Flats Plant Microwave Solidification Project has application potential to the Mixed Waste Treatment Project and the The Mixed Waste Integrated Program. The technical areas being addressed include (1) waste destruction and stabilization; (2) final waste form; and (3) front-end waste handling and feed preparation. This document covers need for such a program; technology description; significance; regulatory requirements; and accomplishments to date. A list of significant reports published under this project is included

  15. Thermoactivation of viruses by microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Mahnel, H.; von Brodorotti, H.S.

    1981-01-01

    Eight different viruses, suspended in drinking water, were examined for their ability to be inactivated by microwaves from a microwave oven. Up to a virus content of 10/sup 5/ TCID/sub 50//ml inactivation was successful within a few minutes of microwave treatment and occurred in parallel to the heat stability of the viruses. Evidence for direct effects of microwaves on viruses could not be detected. 7 of the viruses studied were inactivated rapidly when temperatures of 50 to 65/sup 0/C under microwave treatment were reached in the flowing water, while a bovine parvovirus was only inactivated by temperatures above 90/sup 0/C. The advantages of a thermal virus-decontamination of fluids and material by microwaves are discussed.

  16. CW 100MW microwave power transfer in space

    International Nuclear Information System (INIS)

    Takayama, K.; Hiramatsu, S.; Shiho, M.

    1991-01-01

    A linear multistage MFEL has been considered as a possible power source for future linear colliders; however, the single-stage experiment cannot be straightforwardly extrapolated to the multistage MFEL. Nevertheless, extensive theoretical and computational studies have demonstrated the feasibility of multistaging. Based on the authors current understanding of the MFEL, they developed the idea of a circular microwave power station (MPS) driven with a single high current beam where many FEL stages are placed along a circle and the remarkable high power of microwave (mw) is generated at each stage. The total power produced is linearly proportional to the number of FEL stages. This huge mw power can be emitted from a large parabola antenna; propagates in space and can be received by a receiver such as parabola antenna or rectenna

  17. Introduction to Microwave Linear [Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, David H

    1999-01-04

    The elements of microwave linear accelerators are introduced starting with the principles of acceleration and accelerating structures. Considerations for microwave structure modeling and design are developed from an elementary point of view. Basic elements of microwave electronics are described for application to the accelerator circuit and instrumentation. Concepts of beam physics are explored together with examples of common beamline instruments. Charged particle optics and lattice diagnostics are introduced. Considerations for fixed-target and colliding-beam experimentation are summarized.

  18. High current, 0.5-MA, fast, 100-ns, linear transformer driver experiments

    Directory of Open Access Journals (Sweden)

    Michael G. Mazarakis

    2009-05-01

    Full Text Available The linear transformer driver (LTD is a new method for constructing high current, high-voltage pulsed accelerators. The salient feature of the approach is switching and inductively adding the pulses at low voltage straight out of the capacitors through low inductance transfer and soft iron core isolation. Sandia National Laboratories are actively pursuing the development of a new class of accelerator based on the LTD technology. Presently, the high current LTD experimental research is concentrated on two aspects: first, to study the repetition rate capabilities, reliability, reproducibility of the output pulses, switch prefires, jitter, electrical power and energy efficiency, and lifetime measurements of the cavity active components; second, to study how a multicavity linear array performs in a voltage adder configuration relative to current transmission, energy and power addition, and wall plug to output pulse electrical efficiency. Here we report the repetition rate and lifetime studies performed in the Sandia High Current LTD Laboratory. We first utilized the prototype ∼0.4-MA, LTD I cavity which could be reliably operated up to ±90-kV capacitor charging. Later we obtained an improved 0.5-MA, LTD II version that can be operated at ±100  kV maximum charging voltage. The experimental results presented here were obtained with both cavities and pertain to evaluating the maximum achievable repetition rate and LTD cavity performance. The voltage adder experiments with a series of double sized cavities (1 MA, ±100  kV will be reported in future publications.

  19. Radiation of transient high-current arcs: energy measurements in the optical range

    International Nuclear Information System (INIS)

    Bauchire, J M; Hong, D; Rabat, H; Riquel, G

    2012-01-01

    When no protection is used, the radiation emitted by a high-power electric arc can be dangerous for the eyes and the skin of a person. To ensure effective protection, it is first necessary to know the energy emitted by such arcs. The aim of our work was to experimentally determine the energy emitted by high-current (from 4 to 40 kA) transient arcs, for two different (10 cm and 2 m) lengths and for electrodes in copper or steel. These experiments enabled the radiative energy of the arcs to be quantified and also showed the influence of metal vapors in the spectral distribution of the radiation.

  20. Coherent radiation from high-current electron beams of linear accelerators and its applications

    International Nuclear Information System (INIS)

    Okuda, Shuichi; Takanaka, Makoto; Nakamura, Mitsumi; Kato, Ryukou; Takahashi, Toshiharu; Nam, Soon-Kwon; Taniguchi, Ryouichi; Kojima, Takao

    2006-01-01

    The characteristics of the far-infrared light source using the coherent radiation emitted from a high-energy short electron bunch have been investigated. The coherent radiation has a continuous spectrum in a submillimeter to millimeter wavelength range and the brightness is relatively high. The spectrum of the radiation is determined by the longitudinal form factor of the electron bunch. The operational conditions of a high-current linear accelerator have been optimized using an electron bunch shape monitor. The coherent transition radiation light source has been applied to absorption spectroscopy for liquid water and to an imaging experiment for a leaf of rose

  1. Regimes of magnetic insulation in a high-current diodes and transmission lines of conical configuration

    International Nuclear Information System (INIS)

    Vasilenko, O.I.; Voronin, V.S.; Lebedev, A.N.

    1977-01-01

    A self-consistent kinematic model of a steady-state electron flow between two electrodes of a high-current diode has been considered with a tapered configuration. All the electrons have presumably been released from the cathode with a zero velocity and some portion of the total current flows along the cathode surface as the conduction current. A set of volt-ampere characteristics has been obtained for the tapered diode with a flat anode. At a preset cathode current the thickness and current of the electron layer increase as the voltage goes up. The considered kinematic model substantiates and specifies a model of the Brillouin parapotential flow

  2. Migrational polarization in high-current density molten salt electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Braunstein, J.; Vallet, C.E.

    1977-01-01

    Electrochemical flux equations based on the thermodynamics of irreversible processes have been derived in terms of experimental transport coefficients for binary molten salt mixtures analogous to those proposed for high temperature batteries and fuel cells. The equations and some numerical solutions indicate steady state composition gradients of significant magnitude. The effects of migrational separation must be considered along with other melt properties in the characterization of electrode behavior, melt composition, operating temperatures and differences of phase stability, wettability and other physicochemical properties at positive and negative electrodes of high current density devices with mixed electrolytes.

  3. Improved High Current Liquid and Gas Targets for Cyclotron Produced Radioisotopes (Saudi Arabia)

    Energy Technology Data Exchange (ETDEWEB)

    Al Jammaz, Ibrahim; AlYanbawi, S.; Van-Heerden, W.; Miliebari, S.; Rahma, S.; Carrol, D. [King Faisal Specialist Hospital & Research Centre, Riyadh (Saudi Arabia)

    2009-07-01

    The development and improvement of target technology for reliable and higher production yields is described with respect to fluorine-18 and krypton-81. This report includes specific studies on: 1) beam degradation, distribution and diagnostic tools for monitoring the beam during irradiation; 2) targets that are capable of withstanding high current beam and consequently high specific activity radiopharmaceuticals; 3) greater understanding of in-target chemical and physical phenomena for the preparation of new radiolabeled species; and 4) recovery and characterization very expensive enriched material. (author)

  4. Catastrophic processes in dielectrics in irradiation by high-current electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Oleshko, V. [Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Lisitsyna, L., E-mail: lisitsyn@tpu.r [Tomsk State University of Architecture and Building, 634003 Tomsk (Russian Federation); Malys, D.; Damamme, G. [Commissariat a l' energie atomique, Paris 75015 (France); Lisitsyn, V. [Tomsk Polytechnic University, 634050 Tomsk (Russian Federation)

    2010-10-01

    The results of the research in explosive decomposition of heavy metal azides initiated by electric ('streamer') charges induced by high-current electron beam have been considered. A physical model for initiation of heavy metal azides explosive decomposition by electron beam has been suggested. The model suggests formation of strong electric field in the sample and its neutralization by ultrasound anode charges. The streamer front generates 'hot spots' which start the formation of explosive decomposition sites in a condensed reactive material.

  5. Development of a high current 250 kV photocathode dc gun

    International Nuclear Information System (INIS)

    Nishimori, Nobuyuki; Nagai, Ryoji; Sawamura, Masaru; Hajima, Ryoichi

    2016-01-01

    We have developed a high current photocathode dc gun at JAEA for the next generation light sources such as an energy recovery linac and high-repetition rate X-ray free electron laser. The gun is equipped with a multialkali photocathode preparation system. Quantum efficiency of 0.37% at 532 nm was obtained for a Cs_3Sb photocathode. The gun was high voltage conditioned up to 230 kV with a cathode electrode. Beam generation test from the multialkali photocathode will be performed by the end of FY2015. (author)

  6. Improved High Current Liquid and Gas Targets for Cyclotron Produced Radioisotopes (Saudi Arabia)

    International Nuclear Information System (INIS)

    Al Jammaz, Ibrahim; AlYanbawi, S.; Van-Heerden, W.; Miliebari, S.; Rahma, S.; Carrol, D.

    2009-01-01

    The development and improvement of target technology for reliable and higher production yields is described with respect to fluorine-18 and krypton-81. This report includes specific studies on: 1) beam degradation, distribution and diagnostic tools for monitoring the beam during irradiation; 2) targets that are capable of withstanding high current beam and consequently high specific activity radiopharmaceuticals; 3) greater understanding of in-target chemical and physical phenomena for the preparation of new radiolabeled species; and 4) recovery and characterization very expensive enriched material. (author)

  7. Application of MO-type gapless flange to beam duct for high-current accelerators

    International Nuclear Information System (INIS)

    Suetsugu, Y.; Shirai, M.; Ohtsuka, M.

    2004-01-01

    The MO-type flange, which can provide a gapless connection between flanges, was studied experimentally aiming to apply it to the beam duct for high-current accelerators. The test flange showed a good vacuum sealing property, although the aperture had a complicated shape, that is, the combination of a circular beam duct and a rectangular antechamber. The structural analysis well reproduced the observed deformation of flange, and utilized to optimize the structure. The MO-type flange is a promising one for the connection flange of the beam duct for future accelerators. (author)

  8. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    International Nuclear Information System (INIS)

    Bouda, N. R.; Pritchard, J.; Weber, R. J.; Mina, M.

    2015-01-01

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/−20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG 1 ) and MOSFET circuits (HCMFG 2 ) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed

  9. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Science.gov (United States)

    Bouda, N. R.; Pritchard, J.; Weber, R. J.; Mina, M.

    2015-05-01

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/-20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG1) and MOSFET circuits (HCMFG2) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  10. Simple laser-driven, metal photocathodes as cold, high-current electron sources

    International Nuclear Information System (INIS)

    Saunders, J.D.; Ringler, T.J.; Builta, L.A.; Kauppila, T.J.; Moir, D.C.; Downey, S.W.

    1987-01-01

    Recent developments in excimer laser design have made near ultraviolet light intensities of several MWcm 2 possible in unfocused beams. These advances and recent experiments indicate that high-current, simple-metal photoemissive electron guns are now feasible. Producing more than 50 Acm 2 of illuminated cathode surface, the guns could operate at vacuums of 10 -6 torr with no complicated system components inside the vacuum enclosure. The electron beam produced by such photoemission guns would have very low emittance and high brightness. This beam would also closely follow the temporal characteristics of the laser pulse, making fast risetime, ultrashort electron beam pulses possible

  11. Anisotropy of ultraviolet radiation of high current discharge in a plasma of exploding wire

    International Nuclear Information System (INIS)

    Bogolyubskij, S.L.

    1987-01-01

    The experiments on exploding thin wires in a diode of a high current generator of relativistic electron beams ''Triton'' have demonstrated that the presence of a hot plasma corona and a colder and denser core is typical for appearing radiation coolled Z-pinch. It is found that for 5-10 ns ultraviolet radiation emmitted by plasma channel has a pronounced axial directivity conditioned by quanta with the energy in the 60-120 eV range. Control experiments have shown that this effect is not connected with various near-electrode phenomena

  12. Sparking limits, cavity loading, and beam breakup instability associated with high-current rf linacs

    International Nuclear Information System (INIS)

    Faehl, R.J.; Lemons, D.S.; Thode, L.E.

    1982-01-01

    The limitations on high-current rf linacs due to gap sparking, cavity loading, and the beam breakup instability are studied. It appears possible to achieve cavity accelerating gradients as high as 35 MV/m without sparking. Furthermore, a linear analysis, as well as self-consistent particle simulations of a multipulsed 10 kA beam, indicated that only a negligible small fraction of energy is radiated into nonfundamental cavity modes. Finally, the beam breakup instability is analyzed and found to be able to magnify initial radial perturbations by a factor of no more than about 20 during the beam transit time through a 1 GeV accelerator

  13. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Energy Technology Data Exchange (ETDEWEB)

    Bouda, N. R., E-mail: nybouda@iastate.edu; Pritchard, J.; Weber, R. J.; Mina, M. [Department of Electrical and Computer engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2015-05-07

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/−20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG{sub 1}) and MOSFET circuits (HCMFG{sub 2}) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  14. Measurements of high-current electron beams from X pinches and wire array Z pinches

    International Nuclear Information System (INIS)

    Shelkovenko, T. A.; Pikuz, S. A.; Blesener, I. C.; McBride, R. D.; Bell, K. S.; Hammer, D. A.; Agafonov, A. V.; Romanova, V. M.; Mingaleev, A. R.

    2008-01-01

    Some issues concerning high-current electron beam transport from the X pinch cross point to the diagnostic system and measurements of the beam current by Faraday cups are discussed. Results of computer simulation of electron beam propagation from the pinch to the Faraday cup give limits for the measured current for beams having different energy spreads. The beam is partially neutralized as it propagates from the X pinch to a diagnostic system, but within a Faraday cup diagnostic, space charge effects can be very important. Experimental results show evidence of such effects.

  15. High current relativistic beam propagates stably in gas surrounded by nonconducting walls

    International Nuclear Information System (INIS)

    Clark, J.C.

    1977-01-01

    LLL has been studying the propagation of high current electron beams for a number of years to understand their behavior for use in a variety of experimental uses. Our latest experiments have shown that a mildly relativistic electron beam of 10 to 15 kA and a pulse width of 30 to 40 ns can propagate stably and with no net current transfer in insulating tubes filled with neutral gases. These experiments have been performed in the Magnetic Fusion Energy program where Electronics Engineering has been operating an electron beam accelerator, designing some of the diagnostics, such as laser interferometers, and performing the experiments. This article briefly describes our experimental observations

  16. Non-Ionizing Radiation Used in Microwave Ovens

    Science.gov (United States)

    ... Non-Ionizing Radiation Used in Microwave Ovens Non-Ionizing Radiation Used in Microwave Ovens Explore the interactive, virtual ... can do Where to learn more About Non-Ionizing Radiation Used in Microwave Ovens Microwave Oven. Microwave ovens ...

  17. Various categories of defects after surface alloying induced by high current pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Dian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze, E-mail: oaktang@hit.edu.cn [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Gu, Le [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-10-01

    Highlights: • Four kinds of defects are found during surface alloying by high current electron beam. • Exploring the mechanism how these defects appear after irradiation. • Increasing pulsing cycles will help to get good surface quality. • Choosing proper energy density will increase surface quality. - Abstract: High current pulsed electron beam (HCPEB) is an attractive advanced materials processing method which could highly increase the mechanical properties and corrosion resistance. However, how to eliminate different kinds of defects during irradiation by HCPEB especially in condition of adding new elements is a challenging task. In the present research, the titanium and TaNb-TiW composite films was deposited on the carburizing steel (SAE9310 steel) by DC magnetron sputtering before irradiation. The process of surface alloying was induced by HCPEB with pulse duration of 2.5 μs and energy density ranging from 3 to 9 J/cm{sup 2}. Investigation of the microstructure indicated that there were several forms of defects after irradiation, such as surface unwetting, surface eruption, micro-cracks and layering. How the defects formed was explained by the results of electron microscopy and energy dispersive spectroscopy. The results also revealed that proper energy density (∼6 J/cm{sup 2}) and multi-number of irradiation (≥50 times) contributed to high quality of alloyed layers after irradiation.

  18. Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

    KAUST Repository

    Min, Shixiong

    2016-06-23

    While recent reports have demonstrated that oxide-derived Cu-based electrodes exhibit high selectivity for CO2 reduction at low overpotential, the low catalytic current density (<2 mA/cm2 at -0.45 V vs. RHE) still largely limits its applications for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open frameworks, the resulting Cu foam electrodes prepared at higher temperatures exhibit enhanced electrochemically active surface area and distinct surface structures. In particular, the Cu foam electrode prepared at 500 °C exhibits an extremely high geometric current density of ~9.4 mA/cm2 in CO2-satrurated 0.1 M KHCO3 aqueous solution and achieving ~39% CO and ~23% HCOOH Faradaic efficiencies at -0.45 V vs. RHE. The high activity and significant selectivity enhancement are attributable to the formation of abundant grain-boundary supported active sites and preferable (100) and (111) facets as a result of reconstruction of Cu surface facets. This work demonstrates that the structural integration of Cu foam with open 3D frameworks and the favorable surface structures is a promising strategy to develop an advanced Cu electrocatalyst that can operate at high current density and low overpotential for CO2 reduction.

  19. High Current, Low Voltage Power Converter [20kA, 6V] LHC Converter Prototype

    CERN Document Server

    Jørgensen, H E; Dupaquier, A; Fernqvist, G

    1998-01-01

    The superconducting LHC accelerator requires high currents (~12.5kA) and relatively low voltages (~10 V) for its magnets. The need to install the power converters underground is the driving force for reduced volume and high efficiency. Moreover, the LHC machine will require a very high level of performance from the power converters, particularly in terms of DC stability, dynamic response and also in matters of EMC. To meet these requirements soft-switching techniques will be used. This paper describes the development of a [20kA,6V] power converter intended as a stable high-current source for D CCT calibration and an evaluation prototype for the future LHC converters. The converter is made with a modular concept with five current sources [4kA,6V] in parallel. The 4kA sources are built as plu g-in modules: a diode rectifier on the AC mains with a damped L-C passive filter, a Zero Voltage Switching inverter working at 20 kHz and an output stage (high frequency transformers, Schottky rectifi ers and output filter...

  20. Production of a high-current microsecond electron beam with a large cross section

    International Nuclear Information System (INIS)

    Abdullin, E.N.; Belomytsev, S.Ya.; Bugaev, S.P.; Gorbachev, S.I.; Zaslavskii, V.M.; Zorin, V.P.; Koval'chuk, B.M.; Loginov, S.V.; Matyukov, Yu.N.; Rasputin, R.M.; Tolkachev, V.S.; Shchanin, P.M.

    1991-01-01

    Obtaining high-current wide-aperture electron beams is an important problem in the development of laser technology for controlled nuclear fusion and for solving ecological and technological problems. The main scheme for producing such beams involves the use of generators with intermediate energy storage devices and burst-emission vacuum diodes. Beam pinching is prevented by using an external magnetic field or sectioning the diode into magnetically insulated diodes with currents lower than the limiting current. The length of the electron-current pulse varies from tens to hundreds of nano-seconds and is limited by the parameters of the intermediate storage device. Here the authors study the formation of a high-current electron beam with a square cross section and a current of the order of the limiting current of the diode in the absence of an external magnetic field as well as a 'fast' storage device in the power supply circuit. These conditions as a whole correspond to a simpler electron-source circuit, but the beam forming becomes more complicated. The reason for this is that there is no external magnetic field and that the role of plasma processes in the diode is enhanced by the greater length of the electron-current pulses

  1. High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance a......This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac......-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side...... with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window...

  2. Development and Testing of High Current Hollow Cathodes for High Power Hall Thrusters

    Science.gov (United States)

    Kamhawi, Hani; Van Noord, Jonathan

    2012-01-01

    NASA's Office of the Chief Technologist In-Space Propulsion project is sponsoring the testing and development of high power Hall thrusters for implementation in NASA missions. As part of the project, NASA Glenn Research Center is developing and testing new high current hollow cathode assemblies that can meet and exceed the required discharge current and life-time requirements of high power Hall thrusters. This paper presents test results of three high current hollow cathode configurations. Test results indicated that two novel emitter configurations were able to attain lower peak emitter temperatures compared to state-of-the-art emitter configurations. One hollow cathode configuration attained a cathode orifice plate tip temperature of 1132 degC at a discharge current of 100 A. More specifically, test and analysis results indicated that a novel emitter configuration had minimal temperature gradient along its length. Future work will include cathode wear tests, and internal emitter temperature and plasma properties measurements along with detailed physics based modeling.

  3. The European Microwave Week 2008 and its Microwave Conferences

    NARCIS (Netherlands)

    Hoogeboom, P.; Van Vliet, F.

    2009-01-01

    Under the auspices of the European Microwave Association (EuMA) the 11th annual European Microwave Week was organized in the Amsterdam RAI Congress Centre, The Netherlands, 27-31 October 2008. This major event consisted this year of five conferences, an exhibition, and various side events. The 38th

  4. Converting a Microwave Oven into a Plasma Reactor: A Review

    Directory of Open Access Journals (Sweden)

    Victor J. Law

    2018-01-01

    Full Text Available This paper reviews the use of domestic microwave ovens as plasma reactors for applications ranging from surface cleaning to pyrolysis and chemical synthesis. This review traces the developments from initial reports in the 1980s to today’s converted ovens that are used in proof-of-principle manufacture of carbon nanostructures and batch cleaning of ion implant ceramics. Information sources include the US and Korean patent office, peer-reviewed papers, and web references. It is shown that the microwave oven plasma can induce rapid heterogeneous reaction (solid to gas and liquid to gas/solid plus the much slower plasma-induced solid state reaction (metal oxide to metal nitride. A particular focus of this review is the passive and active nature of wire aerial electrodes, igniters, and thermal/chemical plasma catalyst in the generation of atmospheric plasma. In addition to the development of the microwave oven plasma, a further aspect evaluated is the development of methodologies for calibrating the plasma reactors with respect to microwave leakage, calorimetry, surface temperature, DUV-UV content, and plasma ion densities.

  5. Design of high-energy high-current linac with focusing by superconducting solenoids

    Energy Technology Data Exchange (ETDEWEB)

    Batskikh, G.I.; Belugin, V.M.; Bondarev, B.I. [Moscow Radiotechnical Institute (Russian Federation)] [and others

    1995-10-01

    The advancement of MRTI design for 1.5 GeV and 250 mA ion CW linac was presented in a previous report. In this new linac version all the way from input to output the ions are focused by magnetic fields of superconducting solenoids. The ion limit current is far beyond the needed value. The linac focusing channel offers major advantages over the more conventional ones. The acceptance is 1.7 times as large for such focusing channel as for quadrupole one. Concurrently, a random perturbation sensitivity for such channel is one order of magnitude smaller than in quadrupole channel. These focusing channel features allow to decrease beam matched radius and increase a linac radiation purity without aperture growth. {open_quotes}Regotron{close_quotes} is used as high power generator in linac main part. But D&W cavities need not be divided into sections connected by RF-bridges which denuded them of high coupling factor.

  6. Synthesized and characterization of AI and Gd substitute ferrite for microwave

    International Nuclear Information System (INIS)

    Sudjono, Hans K.; Muljadi; Soepriyanto, Syony

    2000-01-01

    Ferrite for microwave components has been synthesized from garnet ceramics (YIG)substituted by AI and Gd. Magnetic permeability and magnetic polarization changes according to the AI 3+ ion addition. XRD is performed to determined the sintering products at various temperatures. For some samples the magnetic property and performance in microwave region was tested. The testing is conducted in the form of completely assembled circulator which gives data on isolation, insertion loss when microwave circuit analyzer was employed. Due to high level of porosity insertion lost is still to large, improved process is necessary

  7. Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field

    International Nuclear Information System (INIS)

    Takahashi, Masayuki; Ohnishi, Naofumi

    2016-01-01

    A filamentary plasma is reproduced based on a fully kinetic model of electron and ion transports coupled with electromagnetic wave propagation. The discharge plasma transits from discrete to diffusive patterns at a 110-GHz breakdown, with decrease in the ambient pressure, because of the rapid electron diffusion that occurs during an increase in the propagation speed of the ionization front. A discrete plasma is obtained at low pressures when a low-frequency microwave is irradiated because the ionization process becomes more dominant than the electron diffusion, when the electrons are effectively heated by the low-frequency microwave. The propagation speed of the plasma increases with decrease in the incident microwave frequency because of the higher ionization frequency and faster plasma diffusion resulting from the increase in the energy-absorption rate. An external magnetic field is applied to the breakdown volume, which induces plasma filamentation at lower pressures because the electron diffusion is suppressed by the magnetic field. The thrust performance of a microwave rocket is improved by the magnetic fields corresponding to the electron cyclotron resonance (ECR) and its higher-harmonic heating, because slower propagation of the ionization front and larger energy-absorption rates are obtained at lower pressures. It would be advantageous if the fundamental mode of ECR heating is coupled with a lower frequency microwave instead of combining the higher-harmonic ECR heating with the higher frequency microwave. This can improve the thrust performance with smaller magnetic fields even if the propagation speed increases because of the decrease in the incident microwave frequency.

  8. Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Masayuki, E-mail: m.takahashi@al.t.u-tokyo.ac.jp [Department of Aeronautics and Astronautics, The University of Tokyo, Bunkyo-ku 113-8656 (Japan); Ohnishi, Naofumi [Department of Aerospace Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2016-08-14

    A filamentary plasma is reproduced based on a fully kinetic model of electron and ion transports coupled with electromagnetic wave propagation. The discharge plasma transits from discrete to diffusive patterns at a 110-GHz breakdown, with decrease in the ambient pressure, because of the rapid electron diffusion that occurs during an increase in the propagation speed of the ionization front. A discrete plasma is obtained at low pressures when a low-frequency microwave is irradiated because the ionization process becomes more dominant than the electron diffusion, when the electrons are effectively heated by the low-frequency microwave. The propagation speed of the plasma increases with decrease in the incident microwave frequency because of the higher ionization frequency and faster plasma diffusion resulting from the increase in the energy-absorption rate. An external magnetic field is applied to the breakdown volume, which induces plasma filamentation at lower pressures because the electron diffusion is suppressed by the magnetic field. The thrust performance of a microwave rocket is improved by the magnetic fields corresponding to the electron cyclotron resonance (ECR) and its higher-harmonic heating, because slower propagation of the ionization front and larger energy-absorption rates are obtained at lower pressures. It would be advantageous if the fundamental mode of ECR heating is coupled with a lower frequency microwave instead of combining the higher-harmonic ECR heating with the higher frequency microwave. This can improve the thrust performance with smaller magnetic fields even if the propagation speed increases because of the decrease in the incident microwave frequency.

  9. Microwave assisted synthesis of core–shell LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C nanocomposite cathode for high-performance lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huanhuan [Automotive Engineering Research Institute, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013 (China); Li, Yunxing [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Chen, Long; Jiang, Haobin [Automotive Engineering Research Institute, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013 (China); Wei, Jinping [Institute of New Energy Material Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071 (China); Wang, Hongbo [China Aviation Lithium Battery Co. Ltd., Luoyang 471003 (China); Wang, Yaping, E-mail: wangyaping@ujs.edu.cn [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2014-12-25

    Highlights: • We firstly report a fast microwave heating way to prepare LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C. • The reversible discharge capacity of LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C is about 169 mA h g{sup −1}. • LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C nanocomposite elucidates excellent cyclic stability. • LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C nanocomposite exhibits attractive rate capability. - Abstract: A microwave assisted method is developed for synthesizing pure LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4} and LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C nanocomposite. Olivine LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4} coated with uniform amorphous carbon film of ∼5 nm in thickness with an average size of ∼200 nm is successfully obtained. Compared with pure LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}, LiFe{sub 1/3}Mn{sub 1/3}Co{sub 1/3}PO{sub 4}/C composite presents enhanced electrochemical Li-ion intercalation performances. It exhibits a high discharge capacity of 169 mA h g{sup −1} at 0.1 C (theoretical capacity is 170 mA h g{sup −1}). The capacity retention is 99% after 30 cycles. Furthermore, the capacities are still retained 101 at 5 C and 76 mA h g{sup −1} and 20 C, respectively. Carbon coating can significantly improve the Li-ion diffusion, the reversibility of lithium extraction/insertion and electrical conductivity of LiCo{sub 1/3}Mn{sub 1/3}Fe{sub 1/3}PO{sub 4}.

  10. Simulation of 10 A electron beam formation and collection for a high current EBIS

    International Nuclear Information System (INIS)

    Kponou, A.; Beebe, E.; Pikin, A.; Kuznetsov, G.; Batazova, M.; Tiunov, M.

    1997-01-01

    Development of an Electron Beam Ion Source (EBIS) for the Relativistic Heavy Ion Collider (RHIC) at BNL requires operating with a 10 A electron beam, which is approximately an order of magnitude higher current than in any existing EBIS device. A test stand is presently being designed and constructed where EBIS components will be twisted. It will be reported in a separate paper at this Conference. The design of the 10 A electron gun, drift tubes and electron collector requires extensive computer simulations. Calculations have been performed at Novosibirsk and BNL using two different programs, SAM and EGUN. Results of these simulations will be presented

  11. Non-Linear Excitation of Ion Acoustic Waves

    DEFF Research Database (Denmark)

    Michelsen, Poul; Hirsfield, J. L.

    1974-01-01

    The excitation of ion acoustic waves by nonlinear coupling of two transverse magnetic waves generated in a microwave cavity was investigated. Measurements of the wave amplitude showed good agreement with calculations based on the Vlasov equation.......The excitation of ion acoustic waves by nonlinear coupling of two transverse magnetic waves generated in a microwave cavity was investigated. Measurements of the wave amplitude showed good agreement with calculations based on the Vlasov equation....

  12. PROGRAMMING THE MICROWAVE-OVEN

    NARCIS (Netherlands)

    KOK, LP; VISSER, PE; BOON, ME

    1994-01-01

    Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue,

  13. Microwave Radiometry in Remote Sensing

    DEFF Research Database (Denmark)

    Gudmandsen, Preben

    1982-01-01

    Microwave radiometry has shown its capabilities of observing and monitoring large-scale geophysical observables from space. Examples are sea surface temperature and surface wind over the ocean, sea ice extent, concentration and category and snow cover extent and water content. At low microwave fr...

  14. Advances on integrated microwave photonics

    DEFF Research Database (Denmark)

    Dong, Jianji; Liao, Shasha; Yan, Siqi

    2017-01-01

    Integrated microwave photonics has attracted a lot of attentions and makes significant improvement in last 10 years. We have proposed and demonstrated several schemes about microwave photonics including waveform generation, signal processing and energy-efficient micro-heaters. Our schemes are all...

  15. Computer-Generated Microwave Holograms.

    Science.gov (United States)

    Leming, Charles W.; Hastings, Orestes Patterson, III

    1980-01-01

    Described is the phasor method of superposition of waves. The intensity pattern from a system of microwave sources is calculated point by point on a plane corresponding to a film emulsion, and then printed and directly converted to a hologram for 3-cm microwaves. Calculations, construction, and viewing of holograms are included. (Author/DS)

  16. The cosmic microwave background

    International Nuclear Information System (INIS)

    Silk, J.

    1991-01-01

    Recent limits on spectral distortions and angular anisotropies in the cosmic microwave background are reviewed. The various backgrounds are described, and the theoretical implications are assessed. Constraints on inflationary cosmology dominated by cold dark matter (CDM) and on open cosmological models dominated by baryonic dark matter (BDM), with, respectively, primordial random phase scale-invariant curvature fluctuations or non-gaussian isocurvature fluctuations are described. More exotic theories are addressed, and I conclude with the 'bottom line': what theories expect experimentalists to be measuring within the next two to three years without having to abandon their most cherished theorists. (orig.)

  17. 2-mm microwave interferometer

    International Nuclear Information System (INIS)

    Futch, A.H.; Mortensen, W.K.

    1977-01-01

    A 2-mm microwave interferometer has been developed, and phase shift measurements have been made on the Baseball II experiment. The interferometer system employs a 140-GHz receiver for double down conversion of the plasma signal to a 60-MHz, IF frequency. The 140-GHz references signal is also down-converted and compared with the plasma signal to provide the desired phase change of the signal passing through the plasma. A feedback voltage from a 60-MHz discriminator to a voltage-controlled oscillator in the receiver provides frequency stability of the 60-MHz IF signals

  18. Microwave warning device

    International Nuclear Information System (INIS)

    Shriner, W.

    1981-01-01

    A device for warning a person carrying or wearing it of the presence of dangerous microwave radiation is fully powered by the radiations being detected. A very low-wattage gas-discharge lamp is energized by a broadly or a sharply tuned receiver circuit including dipole antennas or one antenna and a ''grounding'' casing element. The casing may be largely and uniformly transparent or have different areas gradedly light-transmissive to indicate varying radiation intensities. The casing can be made in the shape of a pocket watch, fountain pen, bracelet or finger ring, etc

  19. Resonant freak microwaves

    International Nuclear Information System (INIS)

    Aguiar, F.M. de

    2011-01-01

    The Helmholtz equation describing transverse magnetic modes in a closed flat microwave resonator with 60 randomly distributed discs is numerically solved. At lower frequencies, the calculated wave intensity spatially distributed obeys the universal Porter-Thomas form if localized modes are excluded. A superposition of resonant modes is shown to lead to rare events of extreme intensities (freak waves) at localized 'hot spots'. The temporally distributed intensity of such a superposition at the center of a hot spot also follows the Porter-Thomas form. Branched modes are found at higher frequencies. The results bear resemblance to recent experiments reported in an open cavity.

  20. DSN Microwave Antenna Holography

    Science.gov (United States)

    Rochblatt, D. J.; Seidel, B. L.

    1984-01-01

    The DSN microwave antenna holography project will obtain three-dimensional pictures of the large DSN antenna surfaces. These pictures must be of suffi icient resolution to allow adjustment of the reflector panels to an rms surface of 0.5 mm (0.25 mm, goal). The major parameters and equations needed to define a holographic measurement system are outlined and then the proof of concept demonstration measurement that was made at DSS-43 (Australia) that resulted in contour maps with spatial resolution of 7 m in the aperture plane and resolution orthogonal to the aperture plane of 0.7 mm was discussed.