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Sample records for high brightness electron

  1. High brightness electron accelerator

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of accelerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity. 5 figs

  2. High-brightness electron injectors

    International Nuclear Information System (INIS)

    Sheffield, R.L.

    1987-01-01

    Free-electron laser (FEL) oscillators and synchrotron light sources require pulse trains of high peak brightness and, in some applications, high-average power. Recent developments in the technology of photoemissive and thermionic electron sources in rf cavities for electron-linac injector applications offer promising advances over conventional electron injectors. Reduced emittance growth in high peak-current electron injectors may be achieved by using high field strengths and by linearizing the radial component of the cavity electric field at the expense of lower shunt impedance

  3. The Eindhoven High-Brightness Electron Programme

    NARCIS (Netherlands)

    Brussaard, G.J.H.; Wiel, van der M.J.

    2004-01-01

    The Eindhoven High-Brightness programme is aimed at producing ultra-short intense electron bunches from compact accelerators. The RF electron gun is capable of producing 100 fs electron bunches at 7.5 MeV and 10 pC bunch charge. The DC/RF hybrid gun under development will produce bunches <75 fs at

  4. Considerations for high-brightness electron sources

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1990-01-01

    Particle accelerators are now used in many areas of physics research and in industrial and medical applications. New uses are being studied to address major societal needs in energy production, materials research, generation of intense beams of radiation at optical and suboptical wavelengths, treatment of various kinds of waste, and so on. Many of these modern applications require a high intensity beam at the desired energy, along with a very good beam quality in terms of the beam confinement, aiming, or focusing. Considerations for ion and electron accelerators are often different, but there are also many commonalties, and in fact, techniques derived for one should perhaps more often be considered for the other as well. We discuss some aspects of high-brightness electron sources here from that point of view. 6 refs

  5. Very-High-Brightness Picosecond Electron Source

    International Nuclear Information System (INIS)

    Bluem, H.

    2003-01-01

    Bright, RF photocathode electron guns are the source of choice for most high-performance research accelerator applications. Some of these applications are pushing the performance boundaries of the present state-of-the-art guns. Advanced Energy Systems is developing a novel photocathode RF gun that shows excellent promise for extending gun performance. Initial gun simulations with only a short booster accelerator easily break the benchmark emittance of one micron for 1 nC of bunch charge. The pulse length in these simulations is less than 2 ps. It is expected that with more detailed optimization studies, the performance can be further improved. The performance details of the gun will be presented. In addition, we will discuss the present design concept along with the status of the project

  6. Recent advances in high-brightness electron guns at AES

    International Nuclear Information System (INIS)

    Bluem, H.; Todd, A.M.M.; Cole, M.D.; Rathke, J.; Schultheiss, T.

    2003-01-01

    We describe a number of active Advanced Energy Systems projects pertaining to the development of advanced, high-brightness electron guns for various applications. These projects include a fully superconducting, CW RF gun, nearing test, that utilizes the niobium surface as the photocathode material. An integrated 100 mA, low emittance DC/SRF gun, ideal as an injector for ERL-type light sources and intended as the injector for a 100 kW FEL, is in late design stage. A parallel high-power, CW, normal-conducting L-band RF gun project has just begun. The early performance analysis for this gun also shows good promise as an injector for ERL-type light sources. Lastly, a fully axisymmetric RF gun, operating in X-band, is being studied as a source of extremely bright electron bunches

  7. The Physics and Applications of High Brightness Electron Beams

    Science.gov (United States)

    Palumbo, Luigi; Rosenzweig, J.; Serafini, Luca

    2007-09-01

    Plenary sessions. RF deflector based sub-Ps beam diagnostics: application to FEL and advanced accelerators / D. Alesini. Production of fermtosecond pulses and micron beam spots for high brightness electron beam applications / S.G. Anderson ... [et al.]. Wakefields of sub-picosecond electron bunches / K.L.F. Bane. Diamond secondary emitter / I. Ben-Zvi ... [et al.]. Parametric optimization for an X-ray free electron laser with a laser wiggler / R. Bonifacio, N. Piovella and M.M. Cola. Needle cathodes for high-brightness beams / C.H. Boulware ... [et al.]. Non linear evolution of short pulses in FEL cascaded undulators and the FEL harmonic cascade / L. Giannessi and P. Musumeci. High brightness laser induced multi-meV electron/proton sources / D. Giulietti ... [et al.]. Emittance limitation of a conditioned beam in a strong focusing FEL undulator / Z. Huang, G. Stupakov and S. Reiche. Scaled models: space-charge dominated electron storage rings / R.A. Kishek ... [et al.]. High brightness beam applications: energy recovered linacs / G.A. Krafft. Maximizing brightness in photoinjectors / C. Limborg-Deprey and H. Tomizawa. Ultracold electron sources / O.J. Luiten ... [et al.]. Scaling laws of structure-based optical accelerators / A. Mizrahi, V. Karagodsky and L. Schächter. High brightness beams-applications to free-electron lasers / S. Reiche. Conception of photo-injectors for the CTF3 experiment / R. Roux. Superconducting RF photoinjectors: an overview / J. Sekutowicz. Status and perspectives of photo injector developments for high brightness beams / F. Stephan. Results from the UCLA/FNLP underdense plasma lens experiment / M.C. Thompson ... [et al.]. Medical application of multi-beam compton scattering monochromatic tunable hard X-ray source / M. Uesaka ... [et al.]. Design of a 2 kA, 30 fs RF-photoinjector for waterbag compression / S.B. Van Der Geer, O.J. Luiten and M.J. De Loos. Proposal for a high-brightness pulsed electron source / M. Zolotorev ... [et al

  8. ROLE OF DIAMOND SECONDARY EMITTERS IN HIGH BRIGHTNESS ELECTRON SOURCES

    International Nuclear Information System (INIS)

    2005-01-01

    In this paper we explore the possibility of using diamond secondary emitter in a high average current electron injector to amplify the current from the photocathode and to isolate the cathode and the injector from each other to increase the life time of the cathode and preserve the performance of the injector. Secondary electron yield of 225 and current density of 0.8 a/cm 2 have been measured in the transmission mode from type 2 a natural diamond. Although the diamond will be heated during normal operation in the injector, calculations indicate that by cryogenically cooling the diamond, the temperature gradient along the diamond can be maintained within the acceptable range. The electron energy and temporal distributions are expected to be narrow from this device resulting in high brightness beams. Plans are underway to measure the SEY in emission mode, fabricate photocathode-diamond capsule and test diamond and capsule in superconducting RF injector

  9. High-brightness electron source driven by laser

    International Nuclear Information System (INIS)

    Zhao Kui; Geng Rongli; Wang Lifang

    1996-01-01

    A DC high-brightness laser driven by photo emissive electron gun is being developed at Beijing University, in order to produce 50∼100 ps electron bunches of high quality. The gun consists of a photocathode preparation chamber and a DC acceleration cavity. Different ways of fabricating photocathode, such as chemical vapor deposition, ion beam implantation and ion beam enhanced deposition, can be adopted. The acceleration gap is designed with the aid of simulation codes EGUN and POISSON. 100 kV DC high voltage is fed to the anode through a careful designed ceramic insulator. The laser system is a mode locked Nd-YAG oscillator proceeded by an amplifier at 10 Hz repetition rate, which can deliver three different wavelength (1064/532/266 nm). The combination of a superconducting cavity with the photocathode preparation chamber is discussed

  10. Velocity bunching of high-brightness electron beams

    Directory of Open Access Journals (Sweden)

    S. G. Anderson

    2005-01-01

    Full Text Available Velocity bunching has been recently proposed as a tool for compressing electron beam pulses in modern high brightness photoinjector sources. This tool is familiar from earlier schemes implemented for bunching dc electron sources, but presents peculiar challenges when applied to high current, low emittance beams from photoinjectors. The main difficulty foreseen is control of emittance oscillations in the beam in this scheme, which can be naturally considered as an extension of the emittance compensation process at moderate energies. This paper presents two scenarios in which velocity bunching, combined with emittance control, is to play a role in nascent projects. The first is termed ballistic bunching, where the changing of relative particle velocities and positions occur in distinct regions, a short high gradient linac, and a drift length. This scenario is discussed in the context of the proposed ORION photoinjector. Simulations are used to explore the relationship between the degree of bunching, and the emittance compensation process. Experimental measurements performed at the UCLA Neptune Laboratory of the surprisingly robust bunching process, as well as accompanying deleterious transverse effects, are presented. An unanticipated mechanism for emittance growth in bends for highly momentum chirped beam was identified and studied in these experiments. The second scenario may be designated as phase space rotation, and corresponds closely to the recent proposal of Ferrario and Serafini. Its implementation for the compression of the electron beam pulse length in the PLEIADES inverse Compton scattering (ICS experiment at LLNL is discussed. It is shown in simulations that optimum compression may be obtained by manipulation of the phases in low gradient traveling wave accelerator sections. Measurements of the bunching and emittance control achieved in such an implementation at PLEIADES, as well as aspects of the use of velocity-bunched beam directly

  11. Advanced laser technologies for high-brightness photocathode electron gun

    International Nuclear Information System (INIS)

    Tomizawa, Hiromitsu

    2012-01-01

    A laser-excited photocathode RF gun is one of the most reliable high-brightness electron beam sources for XFELs. Several 3D laser shaping methods have been developed as ideal photocathode illumination sources at SPring-8 since 2001. To suppress the emittance growth caused by nonlinear space-charge forces, the 3D cylindrical UV-pulse was optimized spatially as a flattop and temporally as squarely stacked chirped pulses. This shaping system is a serial combination of a deformable mirror that adaptively shapes the spatial profile with a genetic algorithm and a UV-pulse stacker that consists of four birefringent α-BBO crystal rods for temporal shaping. Using this 3D-shaped pulse, a normalized emittance of 1.4 πmm mrad was obtained in 2006. Utilizing laser's Z-polarization, Schottky-effect-gated photocathode gun was proposed in 2006. The cathode work functions are reduced by a laser-induced Schottky effect. As a result of focusing a radially polarized laser pulse with a hollow lens in vacuum, the Z-field (Z-polarization) is generated at the cathode. (author)

  12. Advanced Laser Technologies for High-brightness Photocathode Electron Gun

    Science.gov (United States)

    Tomizawa, Hiromitsu

    A laser-excited photocathode RF gun is one of the most reliable high-brightness electron beam sources for XFELs. Several 3D laser shaping methods have been developed as ideal photocathode illumination sources at SPring-8 since 2001. To suppress the emittance growth caused by nonlinear space-charge forces, the 3D cylindrical UV-pulse was optimized spatially as a flattop and temporally as squarely stacked chirped pulses. This shaping system is a serial combination of a deformable mirror that adaptively shapes the spatial profile with a genetic algorithm and a UV-pulse stacker that consists of four birefringent α-BBO crystal rods for temporal shaping. Using this 3D-shaped pulse, a normalized emittance of 1.4 π mm mrad was obtained in 2006. Utilizing laser's Z-polarization, Schottky-effect-gated photocathode gun was proposed in 2006. The cathode work functions are reduced by a laser-induced Schottky effect. As a result of focusing a radially polarized laser pulse with a hollow lens in vacuum, the Z-field (Z-polarization) is generated at the cathode.

  13. A high-brightness thermionic microwave electron gun

    International Nuclear Information System (INIS)

    Borland, M.

    1991-02-01

    In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun's performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ''State-of-the-art'' microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of e c · μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10 9 e - per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically e · μm

  14. A high-brightness thermionic microwave electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Borland, Michael [Stanford Univ., CA (United States)

    1991-02-01

    In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun`s performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ``State-of-the-art`` microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of < 10 π • mec • μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 109e- per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically < 30 π • me • μm.

  15. Emittance measurement for high-brightness electron guns

    International Nuclear Information System (INIS)

    Kobayashi, H.; Kurihara, T.; Sato, I.; Asami, A.; Yamazaki, Y.; Otani, S.; Ishizawa, Y.

    1992-01-01

    An emittance measurement system based on a high-precision pepper-pot technique has been developed for electron guns with low emittance of around πmm-mrad. Electron guns with a 1 mmφ cathode, the material of which is impregnated tungsten or single-crystal lanthanum hexaboride (La 1-x Ce x )B 6 , have been developed. The performance has been evaluated by putting stress on cathode roughness, which gives rise to an angular divergence, according to the precise emittance measurement system. A new type of cathode holder, which is a modified version of the so called Vogel type, was developed and the beam uniformity has been improved. (Author) 5 figs., tab., 9 refs

  16. Silicon nanowire based high brightness, pulsed relativistic electron source

    Directory of Open Access Journals (Sweden)

    Deep Sarkar

    2017-06-01

    Full Text Available We demonstrate that silicon nanowire arrays efficiently emit relativistic electron pulses under irradiation by a high-intensity, femtosecond, and near-infrared laser (∼1018 W/cm2, 25 fs, 800 nm. The nanowire array yields fluxes and charge per bunch that are 40 times higher than those emitted by an optically flat surface, in the energy range of 0.2–0.5 MeV. The flux and charge yields for the nanowires are observed to be directional in nature unlike that for planar silicon. Particle-in-cell simulations establish that such large emission is caused by the enhancement of the local electric fields around a nanowire, which consequently leads to an enhanced absorption of laser energy. We show that the high-intensity contrast (ratio of picosecond pedestal to femtosecond peak of the laser pulse (10−9 is crucial to this large yield. We extend the notion of surface local-field enhancement, normally invoked in low-order nonlinear optical processes like second harmonic generation, optical limiting, etc., to ultrahigh laser intensities. These electron pulses, expectedly femtosecond in duration, have potential application in imaging, material modification, ultrafast dynamics, terahertz generation, and fast ion sources.

  17. High voltage high brightness electron accelerator with MITL voltage adder coupled to foilless diode

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Poulkey, J.W.; Rovang, D.

    1995-01-01

    The design and analysis of a high brightness electron beam experiment under construction at Sandia National Laboratory is presented. The beam energy is 12 MeV, the current 35-40 kA, the rms radius 0.5 mm, and the pulse duration FWHM 40 ns. The accelerator is SABRE a pulsed inductive voltage adder, and the electron source is a magnetically immersed foilless diode. This experiment has as its goal to stretch the technology to the edge and produce the highest possible electron current in a submillimeter radius beam

  18. High voltage high brightness electron accelerators with MITL voltage adder coupled to foilless diodes

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Poukey, J.W.; Frost, C.A.; Shope, S.L.; Halbleib, J.A.; Turman, B.N.

    1993-01-01

    During the last ten years the authors have extensively studied the physics and operation of magnetically-immersed electron foilless diodes. Most of these sources were utilized as injectors to high current, high energy linear induction accelerators such as those of the RADLAC family. Recently they have experimentally and theoretically demonstrated that foilless diodes can be successfully coupled to self-magnetically insulated transmission line voltage adders to produce very small high brightness, high definition (no halo) electron beams. The RADLAC/SMILE experience opened the path to a new approach in high brightness, high energy induction accelerators. There is no beam drifting through the device. The voltage addition occurs in a center conductor, and the beam is created at the high voltage end in an applied magnetic field diode. This work was motivated by the remarkable success of the HERMES-III accelerator and the need to produce small radius, high energy, high current electron beams for air propagation studies and flash x-ray radiography. In this paper they present experimental results compared with analytical and numerical simulations in addition to design examples of devices that can produce multikiloamp electron beams of as high as 100 MV energies and radii as small as 1 mm

  19. High-brightness electron beam diagnostics at the ATF

    International Nuclear Information System (INIS)

    Wang, X.J.; Ben-Zvi, I.

    1996-01-01

    The Brookhaven Accelerator Test Facility (ATF) is a dedicated user facility for accelerator physicists. Its design is optimized to explore laser acceleration and coherent radiation production. To characterize the low-emittance, picoseconds long electron beam produced by the ATF's photocathode RF gun, we have installed electron beam profile monitors for transverse emittance measurement, and developed a new technique to measure electron beam pulse length by chirping the electron beam energy. We have also developed a new technique to measure the ps slice emittance of a 10 ps long electron beam. Stripline beam position monitors were installed along the beam to monitor the electron beam position and intensity. A stripline beam position monitor was also used to monitor the timing jitter between the RF system and laser pulses. Transition radiation was used to measure electron beam energy, beam profile and electron beam bunch length

  20. Photoemission studies using femtosecond pulses for high brightness electron beams

    International Nuclear Information System (INIS)

    Srinivasan-Rao, T.; Tsang, T.; Fischer, J.

    1990-06-01

    We present the results of a series of experiments where various metal photocathodes are irradiated with ultrashort laser pulses, whose characteristics are: λ = 625 nm, τ = 100 fs, PRR = 89.5 MHz, Hν = 2 eV and average power 25 mW in each of the two beams. The quantum efficiency of the metals range from ∼10 -12 to 10 -8 at a power density of 100 MW/cm 2 at normal incidence. Since all the electrons are emitted due to multiphoton processes, these efficiencies are expected to increase substantially at large intensities. The efficiency at 100 MW/cm 2 has been increased by using p-polarized light at oblique incidence by ∼20x and by mediating the electron emission through surface plasmon excitation by ∼10 3 x. For the low intensities used in these experiments, the electron pulse duration is almost the same as the laser pulse duration for both the bulk and the surface plasmon mediated photoemission. 7 refs., 8 figs., 2 tabs

  1. Efficient temporal shaping of electron distributions for high-brightness photoemission electron guns

    Directory of Open Access Journals (Sweden)

    Ivan V. Bazarov

    2008-04-01

    Full Text Available To achieve the lowest emittance electron bunches from photoemission electron guns, it is essential to limit the uncorrelated emittance growth due to space charge forces acting on the bunch in the vicinity of the photocathode through appropriate temporal shaping of the optical pulses illuminating the photocathode. We present measurements of the temporal profile of electron bunches from a bulk crystal GaAs photocathode illuminated with 520 nm wavelength pulses from a frequency-doubled Yb-fiber laser. A transverse deflecting rf cavity was used to make these measurements. The measured laser pulse temporal profile and the corresponding electron beam temporal profile have about 30 ps FWHM duration, with rise and fall times of a few ps. GaAs illuminated by 520 nm optical pulses is a prompt emitter within our measurement uncertainty of ∼1  ps rms. Combined with the low thermal emittance of negative electron affinity photocathodes, GaAs is a very suitable photocathode for high-brightness photoinjectors. We also report measurements of the photoemission response time for GaAsP, which show a strong dependence on the quantum efficiency of the photocathode.

  2. Studies on a laser driven photoemissive high-brightness electron source and novel photocathodes

    International Nuclear Information System (INIS)

    Geng Rongli; Song Jinhu; Yu Jin

    1997-01-01

    A laser driven photoemissive high-brightness electron source at Beijing University is reported. Through a DC accelerating gap of 100 kV voltage, the device is capable of delivering high-brightness electron beam of 35-100 ps pulse duration when irradiated with a mode-locked YAG laser. The geometry of the gun is optimized with the aid of simulation codes EGUN and POISSON. The results of experimental studies on ion implanted photocathode and cesium telluride photocathode are given. The proposed laser driven superconducting RF gun is also discussed

  3. High power, high brightness electron beam generation in a pulse-line driven pseudospark discharge

    International Nuclear Information System (INIS)

    Destler, W.W.; Segalov, Z.; Rodgers, J.; Ramaswamy, K.; Reiser, M.

    1993-01-01

    High brightness (∼10 10 A/m 2 rad 2 ), high power density (∼10 10 W/cm 2 ) electron beams have been generated by the mating of a hollow-cathode discharge device operating in the pseudospark regime to the output of a high power pulse line accelerator. Very small diameter (∼1 mm) electron beams with currents in the range 500--1000 A and energies in the range 150--300 keV have been generated with effective emittances estimated to be at or below 170 mm mrad. Such emittances are comparable to those achieved in conventional electron beam sources at current densities several orders of magnitude lower than those observed in these experiments

  4. Kiloamp high-brightness beams

    International Nuclear Information System (INIS)

    Caporaso, G.J.

    1987-01-01

    Brightness preservation of high-current relativistic electron beams under two different types of transport is discussed. Recent progress in improving the brightness of laser-guided beams in the Advanced Test Accelerator is reviewed. A strategy for the preservation of the brightness of space-charge-dominated beams in a solenoidal transport system is presented

  5. High-brightness electron beams for production of high intensity, coherent radiation for scientific and industrial applications

    International Nuclear Information System (INIS)

    Kim, K.-J.

    1999-01-01

    Relativistic electron beams with high six-dimensional phase space densities, i.e., high-brightness beams, are the basis for efficient generation of intense and coherent radiation beams for advanced scientific and industrial applications. The remarkable progress in synchrotrons radiation facilities from the first generation to the current, third-generation capability illustrates this point. With the recent development of the high-brightness electron gun based on laser-driven rf photocathodes, linacs have become another important option for high-brightness electron beams. With linacs of about 100 MeV, megawatt-class infrared free-electron lasers can be designed for industrial applications such as power beaming. With linacs of about 10 GeV, 1- angstrom x-ray beams with brightness and time resolution exceeding by several orders of magnitude the current synchrotrons radiation sources can be generated based on self-amplified spontaneous emission. Scattering of a high-brightness electron beam by high power laser beams is emerging as a compact method of generating short-pulse, bright x-rays. In the high-energy frontier, photons of TeV quantum energy could be generated by scattering laser beams with TeV electron beams in future linear colliders

  6. Development of a high brightness, high current SRF photo-electron source for ERL applications

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Axel [Helmholtz-Zentrum Berlin (Germany); Collaboration: bERLinPro Team

    2016-07-01

    Energy recovery linacs (ERL) offer the potential to combine major beam properties of the two main domains of particle accelerators: The low emittance of linear accelerators and the high average beam current of storage rings, while also allowing to compress to short bunches below the ps regime. This makes among other applications ERLs an ideal candidate for future light sources. The beam properties of the ERL are given by the performance of the injection section and hence of the beam source. Helmholtz-Zentrum Berlin is currently designing and building a high average current all superconducting CW driven ERL as a prototype to demonstrate low normalized beam emittance of 1 mm*mrad at 100 mA and short pulses of about 2 ps. In this contribution we discuss the development of this class of a high brightness, high current SRF photo-electron source and present recent commissioning results. Also, alternative approaches at other laboratories are shortly reviewed.

  7. Analysis of a high brightness photo electron beam with self field and wake field effects

    International Nuclear Information System (INIS)

    Parsa, Z.

    1991-01-01

    High brightness sources are the basic ingredients in the new accelerator developments such as Free-Electron Laser experiments. The effects of the interactions between the highly charged particles and the fields in the accelerating structure, e.g. R.F., Space charge and Wake fields can be detrimental to the beam and the experiments. We present and discuss the formulation used, some simulation and results for the Brookhaven National Laboratory high brightness beam that illustrates effects of the accelerating field, space charge forces (e.g. due to self field of the bunch), and the wake field (e.g. arising from the interaction of the cavity surface and the self field of the bunch)

  8. Development of low emittance high brightness electron beams and rf accelerating structures

    International Nuclear Information System (INIS)

    Pellegrini, C.

    1991-01-01

    The main goals of this project were the construction of an S-band RF photoinjector for the production of a high brightness electron beam, and the development of a new type of RF accelerator structure; the Plane wave transformer. By the end of October 1991 the photoinjector had been built, its RF characteristics had been measured at low power, and an initial test of the gun at high RF power had been done. The Plane Wave Transformer had also been built and tested at lower power. In both cases the results obtained are mostly in agreement with the expected and calculated behavior

  9. Initial observations of high-charge, low-emittance electron beams at HIBAF (High Brightness Accelerator FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Carsten, B.E.; Feldman, D.W.; Sheffield, R.L.; Stein, W.E.; Johnson, W.J.; Thode, L.E.; Bender, S.C.; Busch, G.E.

    1990-01-01

    We report our initial measurements of bright (high-charge, low-emittance) electron beams generated at the Los Alamos High Brightness Accelerator FEL (HIBAF) Facility. Normalized emittance values of less than 50 {pi} mm-mrad for charges ranging from 0.7 to 8.7 nC were obtained for single micropulses at a y-waist and at an energy of 14.7 MeV. These measurements were part of the commissioning campaign on the HIBAF photoelectric injector. Macropulse measurements have also been performed and are compared with PARMELA simulations. 5 refs., 8 figs., 3 tabs.

  10. Design and construction of a DC high-brightness laser driven electron gun

    Science.gov (United States)

    Zhao, K.; Geng, R. L.; Wang, L. F.; Zhang, B. C.; Yu, J.; Wang, T.; Wu, G. F.; Song, J. H.; Chen, J. E.

    1996-02-01

    A DC high-brightness laser driven photoemissive electron gun is being developed at Peking University, in order to produce 50-100 ps electron bunches of high quality. The gun consists of a photocathode preparation chamber and a DC acceleration cavity. Different ways of fabricating photocathodes, such as chemical vapor deposition, ion beam implantation and ion beam enhanced deposition, can be adopted. The acceleration gap is designed with the aid of simulation codes EGUN and POISSON. The laser system is a mode-locked Nd-YAG oscillator proceeded by an amplifier at 10 Hz repetition rate, which can deliver three different wavelengths (1064/532/266 nm). The combination of a superconducting cavity with the photocathode preparation chamber is also discussed in this paper.

  11. High-brightness electron guns for linac-based light sources

    International Nuclear Information System (INIS)

    Lewellen, J.W.

    2004-01-01

    Most proposed linac-based light sources, such as single-pass free-electron lasers and energy-recovery-linacs, require very high-brightness electron beams in order to achieve their design performance. These beam requirements must be achieved not on an occasional basis, but rather must be met by every bunch produced by the source over extended periods of time. It is widely assumed that the beam source will be a photocathode electron gun; the selection of accelerator technique (e.g., dc or rf) for the gun is more dependent on the application.The current state of the art of electron beam production is adequate but not ideal for the first generation of linac-based light sources, such as the Linac Coherent Light Source (LCLS) x-ray free-electron laser (X-FEL). For the next generation of linac-based light sources, an order of magnitude reduction in the transverse electron beam emittance is required to significantly reduce the cost of the facility. This is beyond the present state of the art, given the other beam properties that must be maintained. The requirements for current and future linac-based light source beam sources are presented here, along with a review of the present state of the art. A discussion of potential paths towards meeting future needs is presented at the conclusion.

  12. Time-resolved energy spectrum of a pseudospark-produced high-brightness electron beam

    International Nuclear Information System (INIS)

    Myers, T.J.; Ding, B.N.; Rhee, M.J.

    1992-01-01

    The pseudospark, a fast low-pressure gas discharge between a hollow cathode and a planar anode, is found to be an interesting high-brightness electron beam source. Typically, all electron beam produced in the pseudospark has the peak current of ∼1 kA, pulse duration of ∼50 ns, and effective emittance of ∼100 mm-mrad. The energy information of this electron beam, however, is least understood due to the difficulty of measuring a high-current-density beam that is partially space-charge neutralized by the background ions produced in the gas. In this paper, an experimental study of the time-resolved energy spectrum is presented. The pseudospark produced electron beam is injected into a vacuum through a small pinhole so that the electrons without background ions follow single particle motion; the beam is sent through a negative biased electrode and the only portion of beam whose energy is greater than the bias voltage can pass through the electrode and the current is measured by a Faraday cup. The Faraday cup signals with various bias voltage are recorded in a digital oscilloscope. The recorded waveforms are then numerically analyzed to construct a time-resolved energy spectrum. Preliminary results are presented

  13. Transverse Laser Beam Shaping in High Brightness Electron Gun at ATF

    CERN Document Server

    Roychowdhury, S

    2005-01-01

    The brightness of electron beams from a photo injector is influenced by the transverse and longitudinal distribution of the laser beam illuminating the cathode. Previous studies at Brookhaven Accelerator Test Facility have shown that formation of an ideal e-beam with lowest transverse emittance requires uniform circular distribution of the emitted electrons. The use of the uniformly distributed power of the laser beam may not lead to that of the emitted electrons because of the non-uniform quantum efficiency. A proper shaping of the laser beam can compensate for this non-uniformity. In this paper we describe the use of digital light processing (DLP) technique based on digital mirror device (DMD) for spatial modulation of the laser beam, for measurements of the quantum efficiency map, and for creating the desirable e-beam density profiles. A DMD is aμelectronic mechanical system (MEMS) comprising of millions of highly reflectiveμmirrors controlled by underlying electronics. We present exper...

  14. Longitudinal profile diagnostic scheme with subfemtosecond resolution for high-brightness electron beams

    Directory of Open Access Journals (Sweden)

    G. Andonian

    2011-07-01

    Full Text Available High-resolution measurement of the longitudinal profile of a relativistic electron beam is of utmost importance for linac based free-electron lasers and other advanced accelerator facilities that employ ultrashort bunches. In this paper, we investigate a novel scheme to measure ultrashort bunches (subpicosecond with exceptional temporal resolution (hundreds of attoseconds and dynamic range. The scheme employs two orthogonally oriented deflecting sections. The first imparts a short-wavelength (fast temporal resolution horizontal angular modulation on the beam, while the second imparts a long-wavelength (slow angular kick in the vertical dimension. Both modulations are observable on a standard downstream screen in the form of a streaked sinusoidal beam structure. We demonstrate, using scaled variables in a quasi-1D approximation, an expression for the temporal resolution of the scheme and apply it to a proof-of-concept experiment at the UCLA Neptune high-brightness injector facility. The scheme is also investigated for application at the SLAC NLCTA facility, where we show that the subfemtosecond resolution is sufficient to resolve the temporal structure of the beam used in the echo-enabled free-electron laser. We employ beam simulations to verify the effect for typical Neptune and NLCTA parameter sets and demonstrate the feasibility of the concept.

  15. Beam dynamics in an initial part of a high Brightness electron linac

    CERN Document Server

    Ayzatsky, M I; Dovbnya-Kushnir, V A

    2001-01-01

    The paper is focused on problems of obtained a bright electron beam in a system that includes a grid-controlled electron gun,a klystron type type subharmonical buncher, a standing wave fundamental buncher with increasing accelerating field and a short travelling wave accelerating section. Beam focusing is provided by a longitudinal solenoidal magnetic field.It was shown that the proposed system can provide electron bunches with a peak current more than 100 A and normalized r.m.s. emittance no more than phi centre dot mm centre dot mrad.

  16. High Brightness Electron Guns for Next-Generation Light Sources and Accelerators

    International Nuclear Information System (INIS)

    H. Bluem; M.D. Cole; J. Rathke; T. Schultheiss; A.M.M. Todd; I. Ben-Zvi; T. Srinivasan-Rao; P. Colestock; D.C. Nguyen; R.L. Wood; L. Young; D. Janssen; J. Lewellen; G. Neil; H.L. Phillips; J.P. Preble

    2004-01-01

    Advanced Energy Systems continues to develop advanced electron gun and injector concepts. Several of these projects have been previously described, but the progress and status of each will be updated. The project closest to completion is an all superconducting RF (SRF) gun, being developed in collaboration with the Brookhaven National Laboratory, that uses the niobium of the cavity wall itself as the photocathode material. This gun has been fabricated and will shortly be tested with beam. The cavity string for a closely-coupled DC gun and SRF cavity injector that is expected to provide beam quality sufficient for proposed ERL light sources and FELs will be assembled at the Jefferson Laboratory later this year. We are also collaboration with Los Alamos on a prototype CW normal-conducting RF gun with similar performance, that will undergo thermal testing in late 2004. Another CW SRF gun project that uses a high quantum efficiency photocathode, similar to the FZ-Rossendorf approach, has just begun. Finally, we will present the RF design and cold test results for a fully axisymmetric, ultra-high-brightness x-band RF gun

  17. ADVANCED X-BAND TEST ACCELERATOR FOR HIGH BRIGHTNESS ELECTRON AND GAMMA RAY BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, R A; Anderson, S G; Barty, C P; Chu, T S; Ebbers, C A; Gibson, D J; Hartemann, F V; Adolphsen, C; Jongewaard, E N; Raubenheimer, T; Tantawi, S G; Vlieks, A E; Wang, J W

    2010-05-12

    In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.

  18. High-brightness electron beam evolution following laser-based cleaning of a photocathode

    Directory of Open Access Journals (Sweden)

    F. Zhou

    2012-09-01

    Full Text Available Laser-based techniques have been widely used for cleaning metal photocathodes to increase quantum efficiency (QE. However, the impact of laser cleaning on cathode uniformity and thereby on electron beam quality are less understood. We are evaluating whether this technique can be applied to revive photocathodes used for high-brightness electron sources in advanced x-ray free-electron laser (FEL facilities, such as the Linac Coherent Light Source (LCLS at the SLAC National Accelerator Laboratory. The laser-based cleaning was applied to two separate areas of the current LCLS photocathode on July 4 and July 26, 2011, respectively. The QE was increased by 8–10 times upon the laser cleaning. Since the cleaning, routine operation has exhibited a slow evolution of the QE improvement and comparatively rapid improvement of transverse emittance, with a factor of 3 QE enhancement over five months, and a significant emittance improvement over the initial 2–3 weeks following the cleaning. Currently, the QE of the LCLS photocathode is holding constant at about 1.2×10^{-4}, with a normalized injector emittance of about 0.3  μm for a 150-pC bunch charge. With the proper procedures, the laser-cleaning technique appears to be a viable tool to revive the LCLS photocathode. We present observations and analyses for the QE and emittance evolution in time following the laser-based cleaning of the LCLS photocathode, and comparison to the previous studies, the measured thermal emittance versus the QE and comparison to the theoretical model.

  19. High Brightness OLED Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Spindler, Jeffrey [OLEDWorks LLC; Kondakova, Marina [OLEDWorks LLC; Boroson, Michael [OLEDWorks LLC; Hamer, John [OLEDWorks LLC

    2016-05-25

    In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

  20. High brightness ion source

    International Nuclear Information System (INIS)

    Dreyfus, R.W.; Hodgson, R.T.

    1975-01-01

    A high brightness ion beam is obtainable by using lasers to excite atoms or molecules from the ground state to an ionized state in increments, rather than in one step. The spectroscopic resonances of the atom or molecule are used so that relatively long wavelength, low power lasers can be used to obtain such ion beam

  1. Selection of high-brightness, laser-driven cathodes for electron accelerators and FELS

    International Nuclear Information System (INIS)

    Oettinger, P.E.

    1987-01-01

    Very intense, low emittance pulsed beams of electrons can be generated from laser-driven cathodes either by thermionic- or photo-emission. Several hundreds of amperes of electrons per square centimeter were observed for pulse lengths up to 50 ns. A normalized beam brightness of 10 7 A/cm 2 /rad 2 has been measured. These beams can be emission-gated at the cathode surface by modulating the laser-beam. Such beam bunching will generate picosecond-to-microsecond-long pulses at the source. A variety of cathodes are described, and a method of selection for specific applications is presented

  2. Untangling the contributions of image charge and laser profile for optimal photoemission of high-brightness electron beams

    International Nuclear Information System (INIS)

    Portman, J.; Zhang, H.; Makino, K.; Ruan, C. Y.; Berz, M.; Duxbury, P. M.

    2014-01-01

    Using our model for the simulation of photoemission of high brightness electron beams, we investigate the virtual cathode physics and the limits to spatio-temporal and spectroscopic resolution originating from the image charge on the surface and from the profile of the exciting laser pulse. By contrasting the effect of varying surface properties (leading to expanding or pinned image charge), laser profiles (Gaussian, uniform, and elliptical), and aspect ratios (pancake- and cigar-like) under different extraction field strengths and numbers of generated electrons, we quantify the effect of these experimental parameters on macroscopic pulse properties such as emittance, brightness (4D and 6D), coherence length, and energy spread. Based on our results, we outline optimal conditions of pulse generation for ultrafast electron microscope systems that take into account constraints on the number of generated electrons and on the required time resolution.

  3. Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Ratner, Daniel [Stanford Univ., CA (United States)

    2011-05-01

    The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.

  4. Space charge and wake field analysis for a high brightness electron source

    International Nuclear Information System (INIS)

    Parsa, Z.

    1991-01-01

    We present a brief overview of the formalism used, and some simulation results for transverse and longitudinal motion of a bunch of particles moving through a cavity (e.g., the Brookhaven National Laboratory high brightness photocathode gun), including effects of the accelerating field, space charge forces (e.g., arising from the interaction of the cavity surface and the self field of the bunch). 3 refs., 12 figs

  5. Design of a high-brightness, high-duty factor photocathode electron gun

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Birnbaum, I.A.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Ben-Zvi, I.; Batchelor, K.; Gallardo, J.C.; Kirk, H.G.; Srinivasan-Rao, T.; Warren, G.D.

    1991-09-01

    The proposed UV-FEL user's facility at Brookhaven National Laboratory will require a photocathode gun capable of producing short (< 6 psec) bunches of electrons in high repetition rates (5 kHz), low energy spread (< 1.5.%), a peak current of 300 A (after compression) and a total bunch charge of up to 2 nC. At the highest charge the normalized transverse emittance should be less than 7 π mm-mrad. We are presently designing a gun that is expected to exceed these requirements. This gun will consist of 3 1/2 cells, constructed of GlidCop-15, an aluminum oxide dispersion strengthened copper alloy. The gun will be capable of operating at duty factors in excess of 1%. Extensive beam dynamics studies of the gun were used to determine the effect of varying the length of the first cell, shaping the apertures between cells, and increasing the number of cells. In addition, a detailed thermal and mechanical study of the gun was performed to ensure that the thermal stresses were well within the allowable limits and that copper erosion of the water channels would not occur

  6. Tailoring of Highly Intense THz Radiation Through High Brightness Electron Beams Longitudinal Manipulation

    Directory of Open Access Journals (Sweden)

    Flavio Giorgianni

    2016-02-01

    Full Text Available The ultra-short electron beams, produced through the velocity bunching compression technique at the SPARC_LAB test Facility (Frascati, Italy, are used to produce Coherent Transition Radiation in the terahertz (THz range. This paper reports on the main features of this THz source, which have a spectral coverage up to 5 THz, a pulse duration down to 100 fs, and an energy per pulse on the order of tens of μJ. These figures of merits open the possibility to apply this source for nonlinear and THz pump-probe experiments in Solid-State Physics and material science.

  7. High-brightness injector modeling

    International Nuclear Information System (INIS)

    Lewellen, J.W.

    2004-01-01

    There are many aspects to the successful conception, design, fabrication, and operation of high-brightness electron beam sources. Accurate and efficient modeling of the injector are critical to all phases of the process, from evaluating initial ideas to successful diagnosis of problems during routine operation. The basic modeling tasks will vary from design to design, according to the basic nature of the injector (dc, rf, hybrid, etc.), the type of cathode used (thermionic, photo, field emitter, etc.), and 'macro' factors such as average beam current and duty factor, as well as the usual list of desired beam properties. The injector designer must be at least aware of, if not proficient at addressing, the multitude of issues that arise from these considerations; and, as high-brightness injectors continue to move out of the laboratory, the number of such issues will continue to expand.

  8. Electron beam brightness with field immersed emission

    International Nuclear Information System (INIS)

    Boyd, J.K.; Neil, V.K.

    1985-01-01

    The beam quality or brightness of an electron beam produced with field immersed emission is studied with two models. First, an envelope formulation is used to determine the scaling of brightness with current, magnetic field and cathode radius, and examine the equilibrium beam radius. Second, the DPC computer code is used to calculate the brightness of two electron beam sources

  9. Performance of the high brightness linac for the Advanced Free Electron Laser Initiative at Los Alamos

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Austin, R.H.; Chan, K.D.C.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Nguyen, D.C.; Russell, S.J.; Timmer, C.A.

    1993-01-01

    The AFEL accelerator has produced beams of greater than 2 x 10 12 A/m 2 at 1 nC (brightness = 2*I/var-epsilon 2 , with I greater than 100 A and var-epsilon of than 2 π mm-mrad normalized ms emittance). The 1300 MHz standing-wave accelerator uses on-axis coupling cells. The electron source is a photoinjector with a CsK 2 Sb photocathode. The photoinjector is an integral part of a single 11-cell accelerator structure. The accelerator operates between 12 and 18 MeV. The beam emittance growth in the accelerator is minimized by using a photoinjector, a focusing solenoid to correct the emittance growth due to space charge, and a special design of the coupling slots between accelerator cavities to minimize quadrupole effects. This paper describes the experimental results and compares those results with PARMELA simulation. The simulation code PARMELA was modified for this effort. This modified version uses SUPERFISH files for the accelerator cavity fields, MAFIA files for the fields due to the coupling slots in the accelerator cells, and POISSON files for the solenoid field in the gun region

  10. Brightness and coherence of synchrotron radiation and high-gain free electron lasers

    International Nuclear Information System (INIS)

    Kim, K.J.

    1986-10-01

    The characteristics of synchrotron radiation are reviewed with particular attention to its phase-space properties and coherence. The transition of the simple undulator radiation to more intense, more coherent high-gain free electron lasers, is discussed

  11. Surface-plasmon resonance-enhanced multiphoton emission of high-brightness electron beams from a nanostructured copper cathode.

    Science.gov (United States)

    Li, R K; To, H; Andonian, G; Feng, J; Polyakov, A; Scoby, C M; Thompson, K; Wan, W; Padmore, H A; Musumeci, P

    2013-02-15

    We experimentally investigate surface-plasmon assisted photoemission to enhance the efficiency of metallic photocathodes for high-brightness electron sources. A nanohole array-based copper surface was designed to exhibit a plasmonic response at 800 nm, fabricated using the focused ion beam milling technique, optically characterized and tested as a photocathode in a high power radio frequency photoinjector. Because of the larger absorption and localization of the optical field intensity, the charge yield observed under ultrashort laser pulse illumination is increased by more than 100 times compared to a flat surface. We also present the first beam characterization results (intrinsic emittance and bunch length) from a nanostructured photocathode.

  12. High-power, high-brightness pseudospark-produced electron beam driven by improved pulse line accelerator

    International Nuclear Information System (INIS)

    Junbino Zhu; Mingchang Wang; Zhijiang Wang

    1995-01-01

    A high power (200KV), intense current density, low emittance (71mmmrad), high brightness (8x10 10 A/m rad) electron beam was generated in the 10cm long, high-voltage-resistive multi-gap hollow cathode pseudospark chamber filled with 15pa nitrogen and driven by an improved pulse line accelerator. The beam was ejected with the 1mm diameter, the 2.2KA beam current, and the 400ns pulse length, and could propagated 20cm in the drift tube. At a distance of 5cm from the anode it penetrated consecutively an acid-sensitive discoloring film and a 0.05mm-thick copper foil both stuck closely, left 0.6mm and 0.3mm holes on them, respectively. That 10 shots on an acid-sensitive film produced a hole of 1.6mm at 7cm downstream of anode showed its good repeatability. After 60 shots the pseudospark discharge chamber was disassembled and observed that almost no destructive damage traces left on the surfaces of its various electrodes and insulators. But on almost all the surfaces of changeable central hole parts installed on intermediate electrodes there are traces of electron emission from the sides facing the anode and of bombardment on the sides facing the cathode, in contrast with which on the front- and back-surfaces of hollow cathode no visible traces of electron emission from then was observed. In addition, there were different tints, strip-like regions on the side of anode facing the cathode. Another interesting phenomenon was that there were a set of concentric circular or elliptical ring pattern on the acid-sensitive discoloring film got at 5cm from the anode and observed tinder a metallograph. It seems that the pseudospark electron beam is Laminar beam i.e, being possessed of a multi-layer structure, at least in the case of multi-gap pseudospark discharge chamber. It was found experimentally that the quality of pseudospark electron beam is much better than that of the cold-cathode electron beam

  13. Development of a High-Brightness VHF Electron Source at LBNL

    International Nuclear Information System (INIS)

    Lidia, Steven M.; Sannibale, Fernando; Staples, John W.; Virostek, Steve P.; Wells, Russell P.

    2007-01-01

    Currently proposed ERL and high average power FEL projects require electron beam sources that can generate ∼1nC bunch charges at high repetition rates. Many proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose a novel solution that greatly diminishes high voltage breakdown issues while also decreasing peak RF power requirements in a warm copper device, and that has the benefit of mapping the rf oscillation period much more closely to the required beam repetition rate. We present the initial RF and mechanical design for a 750kV electron source and beam injection system utilizing a gun resonant in the VHF band. Beam dynamics simulations demonstrate excellent beam quality preservation and transport

  14. Brightness and coherence of radiation from undulators and high-gain free electron lasers

    International Nuclear Information System (INIS)

    Kim, Kwang-Je.

    1987-03-01

    The purpose of this paper is to review the radiation characteristics of undulators and high-gain free electron lasers (FELs). The topics covered are: a phase-space method in wave optics and synchrotron radiation, coherence from the phase-space point of view, discussions of undulator performances in next-generation synchrotron radiation facility and the characteristics of the high-gain FELs and their performances

  15. Operation of the high-brightness linac for the advanced free-electron laser initiative at Los Alamos

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Austin, R.H.; Chan, K.C.D.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Nguyen, D.C.; Russell, S.J.; Timmer, C.A.

    1993-01-01

    Free-electron lasers and high-energy physics accelerators have increased the demand for very high-brightness beam sources. This paper describes the design of an accelerator which has produced beams of 2.1 π mm-mrad at 1 nC and emittances of 3.7 and 6.5 π mm-mrad for 2 and 3 nC, respectively. The accelerator has been operated between 10 and 18 MeV. The beam emittance growth in the accelerator is minimized by using a photoinjector electron source integrated into the design of the linac, a focusing solenoid to correct the emittance growth caused by space charge, and a special design of the coupling slots between accelerator cavities to minimize quadrupole effects. The FEL has recently operated at 5 microns

  16. Operation of the high brightness linac for the advanced free-electron laser initiative at Los Alamos

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Austin, R.H.; Chan, K.C.D.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Nguyen, D.C.; Russell, S.J.; Timmer, C.A.

    1993-01-01

    Free-electron lasers and high energy physics accelerators have increased the demand for very high-brightness beam sources. This paper describes the design of an accelerator which has produce beams of less than 2.1 π mm-mrad at 1 nC and emittances of 3.7 and 6.5 π mm-mrad for 2 and 3 nC, respectively. The accelerator has been operated between 10 and 18 MeV.The beam emittance growth in the accelerator is minimized by using a photoinjector electron source integrated into the design of the linac, a focusing solenoid to correct the emittance growth caused by space charge, and a special design of the coupling slots between accelerator cavities to minimize quadrupole effects

  17. Development of a high brightness ultrafast Transmission Electron Microscope based on a laser-driven cold field emission source.

    Science.gov (United States)

    Houdellier, F; Caruso, G M; Weber, S; Kociak, M; Arbouet, A

    2018-03-01

    We report on the development of an ultrafast Transmission Electron Microscope based on a cold field emission source which can operate in either DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses which are tightly focused by optical components integrated inside a cold field emission source close to the cathode. The properties of the electron probe (brightness, angular current density, stability) are quantitatively determined. The measured brightness is the largest reported so far for UTEMs. Examples of imaging, diffraction and spectroscopy using ultrashort electron pulses are given. Finally, the potential of this instrument is illustrated by performing electron holography in the off-axis configuration using ultrashort electron pulses. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. High-quality electron beam generation and bright betatron radiation from a cascaded laser wakefield accelerator (Conference Presentation)

    Science.gov (United States)

    Liu, Jiansheng; Wang, Wentao; Li, Wentao; Qi, Rong; Zhang, Zhijun; Yu, Changhai; Wang, Cheng; Liu, Jiaqi; Qing, Zhiyong; Ming, Fang; Xu, Yi; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan

    2017-05-01

    One of the major goals of developing laser wakefiled accelerators (LWFAs) is to produce compact high-energy electron beam (e-beam) sources, which are expected to be applied in developing compact x-ray free-electron lasers and monoenergetic gamma-ray sources. Although LWFAs have been demonstrated to generate multi-GeV e-beams, to date they are still failed to produce high quality e beams with several essential properties (narrow energy spread, small transverse emittance and high beam charge) achieved simultaneously. Here we report on the demonstration of a high-quality cascaded LWFA experimentally via manipulating electron injection, seeding in different periods of the wakefield, as well as controlling energy chirp for the compression of energy spread. The cascaded LWFA was powered by a 1-Hz 200-TW femtosecond laser facility at SIOM. High-brightness e beams with peak energies in the range of 200-600 MeV, 0.4-1.2% rms energy spread, 10-80 pC charge, and 0.2 mrad rms divergence are experimentally obtained. Unprecedentedly high 6-dimensional (6-D) brightness B6D,n in units of A/m2/0.1% was estimated at the level of 1015-16, which is very close to the typical brightness of e beams from state-of-the-art linac drivers and several-fold higher than those of previously reported LWFAs. Furthermore, we propose a scheme to minimize the energy spread of an e beam in a cascaded LWFA to the one-thousandth-level by inserting a stage to compress its longitudinal spatial distribution via velocity bunching. In this scheme, three-segment plasma stages are designed for electron injection, e-beam length compression, and e-beam acceleration, respectively. A one-dimensional theory and two-dimensional particle-in-cell simulations have demonstrated this scheme and an e beam with 0.2% rms energy spread and low transverse emittance could be generated without loss of charge. Based on the high-quality e beams generated in the LWFA, we have experimentally realized a new scheme to enhance the

  19. Diagnostics for high-brightness beams

    International Nuclear Information System (INIS)

    Shafer, R.E.

    1990-01-01

    Special techniques are required for beam diagnostics on high-brightness particle beams. Examples of high-brightness beams include low-emittance proton linacs (either pulsed or CW), electron linacs suitable for free-electron-laser applications, and future linear colliders. Non-interceptive and minimally-interceptive techniques for measuring beam current, position, profile, and transverse and longitudinal emittance will be reviewed. Included will be stripline, wire scanner, laser neutralization, beam-beam scattering, interceptive microgratings, spontaneous emission, optical transition radiation, and other techniques. 24 refs

  20. Teradiode's high brightness semiconductor lasers

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  1. Development of a high brightness electron gun for the Accelerator Test Facility at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Batchelor, K.; Kirk, H.; Sheehan, J.; Woodle, M.; McDonald, K.

    1988-01-01

    An electron gun utilizing a radio frequency accelerating cavity operating at a frequency of 2856 MHZ is described. Low level tests of a model cavity designed for use with either a thermionic or laser driven photo-cathode are presented. Calculations for a laser driven photo-cathode at a bunch charge of 1nC in a 5 psec bunch are given. With this configuration we hope to achieve an emittance (γσ/sub x/σ/sub x/) of 5 to 10 /times/ 10/sup /minus/6/ m /center dot/ rad at an output energy of 4.85 MeV for a 1nC charge. 9 refs., 10 figs., 4 tabs

  2. Measurements and analysis of a high-brightness electron beam collimated in a magnetic bunch compressor

    Science.gov (United States)

    Zhou, F.; Bane, K.; Ding, Y.; Huang, Z.; Loos, H.; Raubenheimer, T.

    2015-05-01

    A collimator located in a magnetic bunch compressor of a linear accelerator driven x-ray free electron laser has many potential applications, such as the removal of horns in the current distribution, the generation of ultrashort beams, and as a diagnostic of the beam slice emittance. Collective effects, however, are a major concern in applying the technique. Systematic measurements of emittance and analysis were performed using a collimator in the first bunch compressor of the Linac Coherent Light Source (LCLS). In the nominal, undercompressed configuration using the collimator we find that the y emittance (nonbending plane) is not increased, and the x emittance (in the bending plane) is increased by about 25%, in comparison to the injector emittance. From the analysis we conclude that the parasitic effects associated with this method are dominated by coherent synchrotron radiation (CSR), which causes a "systematic error" for measuring slice emittance at the bending plane using the collimation method. In general, we find good agreement between the measurements and simulations including CSR. However, for overcompressed beams at smaller collimator gaps, an extra emittance increase is found that does not agree with 1D simulations and is not understood.

  3. Instruments and techniques for analysing the time-resolved transverse phase space distribution of high-brightness electron beams

    International Nuclear Information System (INIS)

    Rudolph, Jeniffa

    2012-01-01

    This thesis deals with the instruments and techniques used to characterise the transverse phase space distribution of high-brightness electron beams. In particular, methods are considered allowing to measure the emittance as a function of the longitudinal coordinate within the bunch (slice emittance) with a resolution in the ps to sub-ps range. The main objective of this work is the analysis of techniques applicable for the time-resolved phase space characterisation for future high-brightness electron beam sources and single-pass accelerators based on these. The competence built up by understanding and comparing different techniques is to be used for the design and operation of slice diagnostic systems for the Berlin Energy Recovery Linac Project (BERLinPro). In the framework of the thesis, two methods applicable for slice emittance measurements are considered, namely the zero-phasing technique and the use of a transverse deflector. These methods combine the conventional quadrupole scan technique with a transfer of the longitudinal distribution into a transverse distribution. Measurements were performed within different collaborative projects. The experimental setup, the measurement itself and the data analysis are discussed as well as measurement results and simulations. In addition, the phase space tomography technique is introduced. In contrast to quadrupole scan-based techniques, tomography is model-independent and can reconstruct the phase space distribution from simple projected measurements. The developed image reconstruction routine based on the Maximum Entropy algorithm is introduced. The quality of the reconstruction is tested using different model distributions, simulated data and measurement data. The results of the tests are presented. The adequacy of the investigated techniques, the experimental procedures as well as the developed data analysis tools could be verified. The experimental and practical experience gathered during this work, the

  4. High brightness beams and applications

    International Nuclear Information System (INIS)

    Sheffield, R.L.

    1995-01-01

    This paper describes the present research on attaining intense bright electron beams. Thermionic systems are briefly covered. Recent and past results from the photoinjector programs are given. The performance advantages and difficulties presently faced by researchers using photoinjectors is discussed. The progress that has been made in photocathode materials, both in lifetime and quantum efficiency, is covered. Finally, a discussion of emittance measurements of photoinjector systems and how the measurement is complicated by the non-thermal nature of the electron beam is presented

  5. Transverse emittance-preserving arc compressor for high-brightness electron beam-based light sources and colliders

    Science.gov (United States)

    Di Mitri, S.; Cornacchia, M.

    2015-03-01

    Bunch length magnetic compression is used in high-brightness linacs driving free-electron lasers (FELs) and particle colliders to increase the peak current of the injected beam. To date, it is performed in dedicated insertions made of few degrees bending magnets and the compression factor is limited by the degradation of the beam transverse emittance owing to emission of coherent synchrotron radiation (CSR). We reformulate the known concept of CSR-driven optics balance for the general case of varying bunch length and demonstrate, through analytical and numerical results, that a 500 pC charge beam can be time-compressed in a periodic 180 deg arc at 2.4 GeV beam energy and lower, by a factor of up to 45, reaching peak currents of up to 2 kA and with a normalized emittance growth at the 0.1 μ \\text{m} rad level. The proposed solution offers new schemes of beam longitudinal gymnastics; an application to an energy recovery linac driving FEL is discussed.

  6. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

    Science.gov (United States)

    Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  7. High brightness semiconductor lasers with reduced filamentation

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.

    1999-01-01

    High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture...

  8. Dark current studies on a normal-conducting high-brightness very-high-frequency electron gun operating in continuous wave mode

    Directory of Open Access Journals (Sweden)

    R. Huang

    2015-01-01

    Full Text Available We report on measurements and analysis of a field-emitted electron current in the very-high-frequency (VHF gun, a room temperature rf gun operating at high field and continuous wave (CW mode at the Lawrence Berkeley National Laboratory (LBNL. The VHF gun is the core of the Advanced Photo-injector Experiment (APEX at LBNL, geared toward the development of an injector for driving the next generation of high average power x-ray free electron lasers. High accelerating fields at the cathode are necessary for the high-brightness performance of an electron gun. When coupled with CW operation, such fields can generate a significant amount of field-emitted electrons that can be transported downstream the accelerator forming the so-called “dark current.” Elevated levels of a dark current can cause radiation damage, increase the heat load in the downstream cryogenic systems, and ultimately limit the overall performance and reliability of the facility. We performed systematic measurements that allowed us to characterize the field emission from the VHF gun, determine the location of the main emitters, and define an effective strategy to reduce and control the level of dark current at APEX. Furthermore, the energy spectra of isolated sources have been measured. A simple model for energy data analysis was developed that allows one to extract information on the emitter from a single energy distribution measurement.

  9. Nonlinear Dynamics of High-Brightness Electron Beams and Beam-Plasma Interactions: Theories, Simulations, and Experiments

    International Nuclear Information System (INIS)

    Bohn, C.L.; Piot, P.; Erdelyi, B.

    2008-01-01

    According to its original Statement of Work (SOW), the overarching objective of this project is: 'To enhance substantially the understanding of the fundamental dynamics of nonequilibrium high-brightness beams with space charge.' Our work and results over the past three and half years have been both intense and fruitful. Inasmuch as this project is inextricably linked to a larger, growing research program - that of the Beam Physics and Astrophysics Group (BPAG) - the progress that it has made possible cannot easily be separated from the global picture. Thus, this summary report includes major sections on 'global' developments and on those that can be regarded as specific to this project.

  10. High-brightness rf linear accelerators

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1986-01-01

    The issue of high brightness and its ramifications in linacs driven by radio-frequency fields is discussed. A history of the RF linacs is reviewed briefly. Some current applications are then examined that are driving progress in RF linacs. The physics affecting the brightness of RF linacs is then discussed, followed by the economic feasibility of higher brightness machines

  11. Generating high-brightness and coherent soft x-ray pulses in the water window with a seeded free-electron laser

    Directory of Open Access Journals (Sweden)

    Kaishang Zhou

    2017-01-01

    Full Text Available We propose a new scheme to generate high-brightness and temporal coherent soft x-ray radiation in a seeded free-electron laser. The proposed scheme is based on the coherent harmonic generation (CHG and superradiant principles. A CHG scheme is first used to generate a coherent signal at ultrahigh harmonics of the seed. This coherent signal is then amplified by a series of chicane-undulator modules via the fresh bunch and superradiant processes in the following radiator. Using a representative of a realistic set of parameters, three-dimensional simulations have been carried out and the simulations results demonstrated that 10 GW-level ultrashort (∼20  fs coherent radiation pulses in the water window can be achieved by using a 1.6 GeV electron beam based on the proposed technique.

  12. Bright field electron microscopy of biological specimens

    International Nuclear Information System (INIS)

    Johansen, B.V.

    1976-01-01

    A preirradiation procedure is described which preserves negatively stained morphological features in bright field electron micrographs to a resolution of about 1.2 nm. Prior to microscopy the pre-irradiation dose (1.6 x 10 -3 C cm -2 ) is given at low electron optical magnification at five different areas on the grid (the centre plus four 'corners'). This pre-irradiation can be measured either with a Faraday cage or through controlled exposure-developing conditions. Uranyl formate stained T2 bacteriophages and stacked disk aggregates of Tobacco Mosaic Virus (TMV) protein served as test objects. A comparative study was performed on specimens using either the pre-irradiation procedure or direct irradiation by the 'minimum beam exposure' technique. Changes in the electron diffraction pattern of the stain-protein complex and the disappearance of certain morphological features in the specimens were both used in order to compare the pre-irradiation method with the direct exposure technique. After identical electron exposures the pre-irradiation approach gave a far better preservation of specimen morphology. Consequently this procedure gives the microscopist more time to select and focus appropriate areas for imaging before deteriorations take place. The investigation also suggested that microscopy should be carried out between 60,000 and 100,000 times magnification. Within this magnification range, it is possible to take advantage of the phase contrast transfer characteristics of the objective lens while the electron load on the object is kept at a moderate level. Using the pre-irradiation procedure special features of the T2 bacteriophage morphology could be established. (author)

  13. The Los Alamos high-brightness photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    O' Shea, P.G.

    1991-01-01

    For a number of years Los Alamos National Laboratory has been developing photocathode RF guns for high-brightness electron beam applications such as free-electron lasers (FELs). Previously thermionic high-voltage guns have been the source of choice for the electron accelerators used to drive FELs. The performance of such FELs is severely limited by the emittance growth produced by the subharmonic bunching process and also by the low peak current of the source. In a photoinjector, a laser driven photocathode is placed directly in a high-gradient RF accelerating cavity. A photocathode allows unsurpassed control over the current, and the spatial and temporal profile of the beam. In addition the electrodeless emission'' avoids many of the difficulties associated with multi-electrode guns, i.e. the electrons are accelerated very rapidly to relativistic energies, and there are no electrodes to distort the accelerating fields. For the past two years we have been integrating a photocathode into our existing FEL facility by replacing our thermionic gun and subharmonic bunchers with a high-gradient 1.3 GHz photoinjector. The photoinjector, which is approximately 0.6 m in length, produces 6 MeV, 300 A, 15 ps linac, and accelerated to a final energy of 40 MeV. We have recently begun lasing at wavelengths near 3 {mu}m. 16 refs., 2 figs., 5 tabs.

  14. Beam extraction dynamics at the space-charge-limit of the high brightness E-XFEL electron source at DESY-PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ye; Gjonaj, Erion; Weiland, Thomas [TEMF, Technische Universitaet Darmstadt, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

    2015-07-01

    The physics of the photoemission, as one of the key issues for successful operation of linac based free-electron lasers like the European X-ray Free Electron Laser (E-XFEL) and the Free-electron Laser in Hamburg (FLASH), is playing an increasingly important role in the high brightness DESY-PITZ electron source. We study photoemission physics and discuss full three-dimensional numerical modeling of the electron bunch emission. The beam extraction dynamics at the photocathode has been investigated through the 3D fully electromagnetic (EM) Particle-in-Cell (PIC) solver of CST Particle Studio under the assumption of the photoemission source operating at or close to its space charge limit. PIC simulation results have shown good agreements with measurements on total emitted bunch charge for distinct experimental parameters. Further comparisons showed a general failure for the conventional Poisson solver based tracking algorithm to correctly predict the beam dynamics at the space charge limit. It is furthermore found, that fully EM PIC simulations are also consistent with a simple emission model based on the multidimensional Child-Langmuir law.

  15. Laser-powered dielectric-structures for the production of high-brightness electron and x-ray beams

    Science.gov (United States)

    Travish, Gil; Yoder, Rodney B.

    2011-05-01

    Laser powered accelerators have been under intensive study for the past decade due to their promise of high gradients and leveraging of rapid technological progress in photonics. Of the various acceleration schemes under examination, those based on dielectric structures may enable the production of relativistic electron beams in breadbox sized systems. When combined with undulators having optical-wavelength periods, these systems could produce high brilliance x-rays which find application in, for instance, medical and industrial imaging. These beams also may open the way for table-top atto-second sciences. Development and testing of these dielectric structures faces a number of challenges including complex beam dynamics, new demands on lasers and optical coupling, beam injection schemes, and fabrication. We describe one approach being pursued at UCLA-the Micro Accelerator Platform (MAP). A structure similar to the MAP has also been designed which produces periodic deflections and acts as an undulator for radiation production, and the prospects for this device will be considered. The lessons learned from the multi-year effort to realize these devices will be presented. Challenges remain with acceleration of sub-relativistic beams, focusing, beam phase stability and extension of these devices to higher beam energies. Our progress in addressing these hurdles will be summarized. Finally, the demands on laser technology and optical coupling will be detailed.

  16. Discussion of high brightness rf linear accelerators

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1987-01-01

    The fundamental aspects of high-brightness rf linacs are outlined, showing the breadth and complexity of the technology and indicating that synergism with advancements in other areas is important. Areas of technology reviewed include ion sources, injectors, rf accelerator structures, beam dynamics, rf power, and automatic control

  17. A high brightness probe of polymer nanoparticles for biological imaging

    Science.gov (United States)

    Zhou, Sirong; Zhu, Jiarong; Li, Yaping; Feng, Liheng

    2018-03-01

    Conjugated polymer nanoparticles (CPNs) with high brightness in long wavelength region were prepared by the nano-precipitation method. Based on fluorescence resonance energy transfer (FRET) mechanism, the high brightness property of the CPNs was realized by four different emission polymers. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) displayed that the CPNs possessed a spherical structure and an average diameter of 75 nm. Analysis assays showed that the CPNs had excellent biocompatibility, good photostability and low cytotoxicity. The CPNs were bio-modified with a cell penetrating peptide (Tat, a targeted element) through covalent link. Based on the entire wave fluorescence emission, the functionalized CPNs1-4 can meet multichannel and high throughput assays in cell and organ imaging. The contribution of the work lies in not only providing a new way to obtain a high brightness imaging probe in long wavelength region, but also using targeted cell and organ imaging.

  18. Brightness measurement of an electron impact gas ion source for proton beam writing applications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, N.; Santhana Raman, P. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Xu, X.; Pang, R.; Kan, J. A. van, E-mail: phyjavk@nus.edu.sg [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Khursheed, A. [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore)

    2016-02-15

    We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

  19. High-brightness H/sup -/ accelerators

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1987-01-01

    Neutral particle beam (NPB) devices based on high-brightness H/sup -/ accelerators are an important component of proposed strategic defense systems. The basic rational and R and D program are outlined and examples given of the underlying technology thrusts toward advanced systems. Much of the research accomplished in the past year is applicable to accelerator systems in general; some of these activities are discussed

  20. Technological Challenges for High-Brightness Photo-Injectors

    CERN Multimedia

    Suberlucq, Guy

    2004-01-01

    Many applications, from linear colliders to free-electron lasers, passing through light sources and many other electron sources, require high brightness electron beams, usually produced by photo-injectors. Because certain parameters of these applications differ by several orders of magnitude, various solutions were implemented for the design and construction of the three main parts of the photo-injectors: lasers, photocathodes and guns. This paper summarizes the different requirements, how they lead to technological challenges and how R&D programs try to overcome these challenges. Some examples of state-of-the-art parts are presented.

  1. First measurements of electron-beam transit times and micropulse elongation in a photoelectric injector at the High-Brightness Accelerator FEL (HIBAF)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Carlsten, B.E.; Feldman, R.B.

    1990-01-01

    Key aspects of the dynamics of a photoelectric injector (PEI) on the Los Alamos High-Brightness Accelerator FEL (HIBAF) facility have been investigated using a synchroscan streak camera. By phase-locking the streak camera sweep to the reference 108.3 MHz rf signal, the variations of micropulse temporal elongations (30 to 80% over the drive-laser pulse length) and of transit times (25 ps for a 16{degree}-phase change) were observed for the first time. These results were in good agreement with PARMELA simulations. 2 refs., 8 figs.

  2. Advanced prior modeling for 3D bright field electron tomography

    Science.gov (United States)

    Sreehari, Suhas; Venkatakrishnan, S. V.; Drummy, Lawrence F.; Simmons, Jeffrey P.; Bouman, Charles A.

    2015-03-01

    Many important imaging problems in material science involve reconstruction of images containing repetitive non-local structures. Model-based iterative reconstruction (MBIR) could in principle exploit such redundancies through the selection of a log prior probability term. However, in practice, determining such a log prior term that accounts for the similarity between distant structures in the image is quite challenging. Much progress has been made in the development of denoising algorithms like non-local means and BM3D, and these are known to successfully capture non-local redundancies in images. But the fact that these denoising operations are not explicitly formulated as cost functions makes it unclear as to how to incorporate them in the MBIR framework. In this paper, we formulate a solution to bright field electron tomography by augmenting the existing bright field MBIR method to incorporate any non-local denoising operator as a prior model. We accomplish this using a framework we call plug-and-play priors that decouples the log likelihood and the log prior probability terms in the MBIR cost function. We specifically use 3D non-local means (NLM) as the prior model in the plug-and-play framework, and showcase high quality tomographic reconstructions of a simulated aluminum spheres dataset, and two real datasets of aluminum spheres and ferritin structures. We observe that streak and smear artifacts are visibly suppressed, and that edges are preserved. Also, we report lower RMSE values compared to the conventional MBIR reconstruction using qGGMRF as the prior model.

  3. Electron Source Brightness and Illumination Semi-Angle Distribution Measurement in a Transmission Electron Microscope.

    Science.gov (United States)

    Börrnert, Felix; Renner, Julian; Kaiser, Ute

    2018-05-21

    The electron source brightness is an important parameter in an electron microscope. Reliable and easy brightness measurement routes are not easily found. A determination method for the illumination semi-angle distribution in transmission electron microscopy is even less well documented. Herein, we report a simple measurement route for both entities and demonstrate it on a state-of-the-art instrument. The reduced axial brightness of the FEI X-FEG with a monochromator was determined to be larger than 108 A/(m2 sr V).

  4. Record high-average current from a high-brightness photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, Bruce; Barley, John; Bartnik, Adam; Bazarov, Ivan; Cultrera, Luca; Dobbins, John; Hoffstaetter, Georg; Johnson, Brent; Kaplan, Roger; Karkare, Siddharth; Kostroun, Vaclav; Li Yulin; Liepe, Matthias; Liu Xianghong; Loehl, Florian; Maxson, Jared; Quigley, Peter; Reilly, John; Rice, David; Sabol, Daniel [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States); and others

    2013-01-21

    High-power, high-brightness electron beams are of interest for many applications, especially as drivers for free electron lasers and energy recovery linac light sources. For these particular applications, photoemission injectors are used in most cases, and the initial beam brightness from the injector sets a limit on the quality of the light generated at the end of the accelerator. At Cornell University, we have built such a high-power injector using a DC photoemission gun followed by a superconducting accelerating module. Recent results will be presented demonstrating record setting performance up to 65 mA average current with beam energies of 4-5 MeV.

  5. High Brightness Injectors Based On Photocathode DC Gun

    International Nuclear Information System (INIS)

    B. Yunn

    2001-01-01

    Sample results of new injector design method based on a photocathode dc gun are presented, based on other work analytically proving the validity of the emittance compensation scheme for the case even when beam bunching is involved. We have designed several new injectors appropriate for different bunch charge ranges accordingly. Excellent beam quality produced by these injectors clearly shows that a photocathode dc gun can compete with a rf gun on an equal footing as the source of an electron beam for the bunch charge ranging up to 2 nano Coulomb (nC). This work therefore elevates a dc gun based injector to the preferred choice for many ongoing high brightness accelerator projects considering the proven operational stability and high average power capability of the dc gun

  6. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Nellist, Peter D., E-mail: peter.nellist@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Cosgriff, Eireann C.; D' Alfonso, Adrian J.; Morgan, Andrew J.; Allen, Leslie J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Hashimoto, Ayako [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Takeguchi, Masaki [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Mitsuishi, Kazutaka [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Quantum Dot Research Center, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Shimojo, Masayuki [High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Fukaya 369-0293 (Japan)

    2011-06-15

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. -- Research Highlights: {yields} The confocal probe image in a scanning confocal electron microscopy image reveals information about the thickness and height of the crystalline layer. {yields} The form of the contrast in a three-dimensional bright-field scanning confocal electron microscopy image can be explained in terms of the confocal probe image. {yields} Despite the complicated form of the contrast in bright-field scanning confocal electron microscopy, we see that depth information is transferred on a 10 nm scale.

  7. Conceptual design of a bright electron injector based on a laser-driven photocathode rf electron gun

    International Nuclear Information System (INIS)

    Chattopadhyay, S.; Chen, Y.J.; Hopkins, D.; Kim, K.J.; Kung, A.; Miller, R.; Sessler, A.; Young, T.

    1988-09-01

    Conceptual design of a bright electron injector for the 1 GeV high gradient test experiment, envisaged by the LLNL-SLAC-LBL collaboration on the Relativistic Klystron is presented. The design utilizes a high-brightness laser-driven rf photocathode electron gun, similar to the pioneering LANL early studies in concept (different parametrically however), together with achromatic magnetic bunching and transport systems and diagnostics. The design is performed with attention to possible use in an FEL as well. A simple but realistic analytic model including longitudinal and transverse space-charge and rf effects and extensive computer simulation form the basis of the parametric choice for the source. These parameters are used as guides for the design of the picosecond laser system and magnetic bunching section. 4 refs., 5 figs., 2 tabs

  8. Controlling excitons. Concepts for phosphorescent organic LEDs at high brightness

    Energy Technology Data Exchange (ETDEWEB)

    Reineke, Sebastian

    2009-11-15

    This work focusses on the high brightness performance of phosphorescent organic light-emitting diodes (OLEDs). The use of phosphorescent emitter molecules in OLEDs is essential to realize internal electron-photon conversion efficiencies of 100 %. However, due to their molecular nature, the excited triplet states have orders of magnitude longer time constants compared to their fluorescent counterparts which, in turn, strongly increases the probability of bimolecular annihilation. As a consequence, the efficiencies of phosphorescent OLEDs decline at high brightness - an effect known as efficiency roll-off, for which it has been shown to be dominated by triplet-triplet annihilation (TTA). In this work, TTA of the archetype phosphorescent emitter Ir(ppy){sub 3} is investigated in time-resolved photoluminescence experiments. For the widely used mixed system CBP:Ir(ppy){sub 3}, host-guest TTA - an additional unwanted TTA channel - is experimentally observed at high excitation levels. By using matrix materials with higher triplet energies, this effect is efficiently suppressed, however further studies show that the efficiency roll-off of Ir(ppy)3 is much more pronounced than predicted by a model based on Foerster-type energy transfer, which marks the intrinsic limit for TTA. These results suggest that the emitter molecules show a strong tendency to form aggregates in the mixed film as the origin for enhanced TTA. Transmission electron microscopy images of Ir(ppy){sub 3} doped mixed films give direct proof of emitter aggregates. Based on these results, two concepts are developed that improve the high brightness performance of OLEDs. In a first approach, thin intrinsic matrix interlayers are incorporated in the emission layer leading to a one-dimensional exciton confinement that suppresses exciton migration and, consequently, TTA. The second concept reduces the efficiency roll-off by using an emitter molecule with slightly different chemical structure, i.e. Ir(ppy){sub 2

  9. Planned High-brightness Channeling Radiation Experiment at Fermilab's Advanced Superconducting Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Blomberg, Ben [NICADD, DeKalb; Mihalcea, Daniel [NICADD, DeKalb; Panuganti, Harsha [NICADD, DeKalb; Piot, Philippe [Fermilab; Brau, Charles [Vanderbilt U.; Choi, Bo [Vanderbilt U.; Gabella, William [Vanderbilt U.; Ivanov, Borislav [Vanderbilt U.; Mendenhall, Marcus [Vanderbilt U.; Lynn, Christopher [Swarthmore Coll.; Sen, Tanaji [Fermilab; Wagner, Wolfgang [Forschungszentrum Dresden Rossendorf

    2014-07-01

    In this contribution we describe the technical details and experimental setup of our study aimed at producing high-brightness channeling radiation (CR) at Fermilab’s new user facility the Advanced Superconducting Test Accelerator (ASTA). In the ASTA photoinjector area electrons are accelerated up to 40-MeV and focused to a sub-micron spot on a ~40 micron thick carbon diamond, the electrons channel through the crystal and emit CR up to 80-KeV. Our study utilizes ASTA’s long pulse train capabilities and ability to preserve ultra-low emittance, to produce the desired high average brightness.

  10. Quantum Entanglement and High Brightness Laser Source

    Data.gov (United States)

    National Aeronautics and Space Administration — Our focus is on demonstrating high precision (sub-micron) laser ranging for Navigation using a unique high-sensitivity optical correlation receiver with both...

  11. State-Of High Brightness RF Photo-Injector Design

    Science.gov (United States)

    Ferrario, Massimo; Clendenin, Jym; Palmer, Dennis; Rosenzweig, James; Serafini, Luca

    2000-04-01

    The art of designing optimized high brightness electron RF Photo-Injectors has moved in the last decade from a cut and try procedure, guided by experimental experience and time consuming particle tracking simulations, up to a fast parameter space scanning, guided by recent analytical results and a fast running semi-analytical code, so to reach the optimum operating point which corresponds to maximum beam brightness. Scaling laws and the theory of invariant envelope provide to the designers excellent tools for a first parameters choice and the code HOMDYN, based on a multi-slice envelope description of the beam dynamics, is tailored to describe the space charge dominated dynamics of laminar beams in presence of time dependent space charge forces, giving rise to a very fast modeling capability for photo-injectors design. We report in this talk the results of a recent beam dynamics study, motivated by the need to redesign the LCLS photoinjector. During this work a new effective working point for a split RF photoinjector has been discovered by means of the previous mentioned approach. By a proper choice of rf gun and solenoid parameters, the emittance evolution shows a double minimum behavior in the drifting region. If the booster is located where the relative emittance maximum and the envelope waist occur, the second emittance minimum can be shifted at the booster exit and frozen at a very low level (0.3 mm-mrad for a 1 nC flat top bunch), to the extent that the invariant envelope matching conditions are satisfied.

  12. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope.

    Science.gov (United States)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I; Nellist, Peter D; Cosgriff, Eireann C; D'Alfonso, Adrian J; Morgan, Andrew J; Allen, Leslie J; Hashimoto, Ayako; Takeguchi, Masaki; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2011-06-01

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Latest advances in high brightness disk lasers

    Science.gov (United States)

    Kuhn, Vincent; Gottwald, Tina; Stolzenburg, Christian; Schad, Sven-Silvius; Killi, Alexander; Ryba, Tracey

    2015-02-01

    In the last decade diode pumped solid state lasers have become an important tool for many industrial materials processing applications. They combine ease of operation with efficiency, robustness and low cost. This paper will give insight in latest progress in disk laser technology ranging from kW-class CW-Lasers over frequency converted lasers to ultra-short pulsed lasers. The disk laser enables high beam quality at high average power and at high peak power at the same time. The power from a single disk was scaled from 1 kW around the year 2000 up to more than 10 kW nowadays. Recently was demonstrated more than 4 kW of average power from a single disk close to fundamental mode beam quality (M²=1.38). Coupling of multiple disks in a common resonator results in even higher power. As an example we show 20 kW extracted from two disks of a common resonator. The disk also reduces optical nonlinearities making it ideally suited for short and ultrashort pulsed lasers. In a joint project between TRUMPF and IFSW Stuttgart more than 1.3 kW of average power at ps pulse duration and exceptionally good beam quality was recently demonstrated. The extremely low saturated gain makes the disk laser ideal for internal frequency conversion. We show >1 kW average power and >6 kW peak power in multi ms pulsed regime from an internally frequency doubled disk laser emitting at 515 nm (green). Also external frequency conversion can be done efficiently with ns pulses. >500 W of average UV power was demonstrated.

  14. High-brightness switchable multiwavelength remote laser in air

    Energy Technology Data Exchange (ETDEWEB)

    Yao Jinping; Cheng Ya; Xu Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Zeng Bin; Li Guihua; Chu Wei; Ni Jielei; Zhang Haisu [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of Chinese Academy of Sciences, Beijing 100080 (China); Xu Huailiang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Chin, See Leang [Center for Optics, Universite Laval, Quebec City, Quebec G1V 0A6 (Canada)

    2011-11-15

    We demonstrate a harmonic-seeded switchable multiwavelength laser in air driven by intense midinfrared femtosecond laser pulses, in which population inversion occurs at an ultrafast time scale (i.e., less than {approx}200 fs) owing to direct formation of excited molecular nitrogen ions by strong-field ionization of inner-valence electrons. The bright multiwavelength laser in air opens the perspective for remote detection of multiple pollutants based on nonlinear optical spectroscopy.

  15. High-brightness fiber-coupled pump laser development

    Science.gov (United States)

    Price, Kirk; Karlsen, Scott; Leisher, Paul; Martinsen, Robert

    2010-02-01

    We report on the continued development of high brightness laser diode modules at nLIGHT Photonics. These modules, based on nLIGHT's PearlTM product platform, demonstrate excellence in output power, brightness, wavelength stabilization, and long wavelength performance. This system, based on 14 single emitters, is designed to couple diode laser light into a 105 μm fiber at an excitation NA of under 0.14. We demonstrate over 100W of optical power at 9xx nm with a diode brightness exceeding 20 MW/cm2-str with an operating efficiency of approximately 50%. Additional results show over 70W of optical coupled at 8xx nm. Record brilliance at wavelengths 14xx nm and longer will also be demonstrated, with over 15 W of optical power with a beam quality of 7.5 mm-mrad. These results of high brightness, high efficiency, and wavelength stabilization demonstrate the pump technology required for next generation solid state and fiber lasers.

  16. Progress in extremely high brightness LED-based light sources

    Science.gov (United States)

    Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

    2017-09-01

    Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

  17. A new approach for 3D reconstruction from bright field TEM imaging: Beam precession assisted electron tomography

    International Nuclear Information System (INIS)

    Rebled, J.M.; Yedra, Ll.; Estrade, S.; Portillo, J.; Peiro, F.

    2011-01-01

    The successful combination of electron beam precession and bright field electron tomography for 3D reconstruction is reported. Beam precession is demonstrated to be a powerful technique to reduce the contrast artifacts due to diffraction and curvature in thin foils. Taking advantage of these benefits, Precession assisted electron tomography has been applied to reconstruct the morphology of Sn precipitates embedded in an Al matrix, from a tilt series acquired in a range from +49 o to -61 o at intervals of 2 o and with a precession angle of 0.6 o in bright field mode. The combination of electron tomography and beam precession in conventional TEM mode is proposed as an alternative procedure to obtain 3D reconstructions of nano-objects without a scanning system or a high angle annular dark field detector. -- Highlights: → Electron beam precession reduces spurious diffraction contrast in bright field mode. → Bend contour related contrast depends on precession angle. → Electron beam precession is combined with bright field electron tomography. → Precession assisted BF tomography allowed 3D reconstruction of a Sn precipitate.

  18. A new approach for 3D reconstruction from bright field TEM imaging: Beam precession assisted electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rebled, J.M. [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Institut de Ciencia de Materials de Barcelona-CSIC, Campus UAB, 08193 Bellaterra (Spain); Yedra, Ll. [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Estrade, S.; Portillo, J. [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); TEM-MAT, CCiT-UB, Sole i Sabaris 1, 08028 Barcelona (Spain); Peiro, F., E-mail: francesca.peiro@ub.edu [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

    2011-08-15

    The successful combination of electron beam precession and bright field electron tomography for 3D reconstruction is reported. Beam precession is demonstrated to be a powerful technique to reduce the contrast artifacts due to diffraction and curvature in thin foils. Taking advantage of these benefits, Precession assisted electron tomography has been applied to reconstruct the morphology of Sn precipitates embedded in an Al matrix, from a tilt series acquired in a range from +49{sup o} to -61{sup o} at intervals of 2{sup o} and with a precession angle of 0.6{sup o} in bright field mode. The combination of electron tomography and beam precession in conventional TEM mode is proposed as an alternative procedure to obtain 3D reconstructions of nano-objects without a scanning system or a high angle annular dark field detector. -- Highlights: {yields} Electron beam precession reduces spurious diffraction contrast in bright field mode. {yields} Bend contour related contrast depends on precession angle. {yields} Electron beam precession is combined with bright field electron tomography. {yields} Precession assisted BF tomography allowed 3D reconstruction of a Sn precipitate.

  19. Simulations of Beam Optics and Bremsstrahlung for High Intensity and Brightness Channeling Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, J. [Sokendai, Tsukuba; Piot, P. [NIU, DeKalb; Sen, T. [Fermilab

    2018-04-12

    This paper presents X-ray spectra of channeling radiation expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations for a range of bunch charges. We estimate the X-ray spectra including bremsstrahlung background. We discuss how the electron beam distributions after the diamond crystal are affected by channeling. We discuss an X-ray detector system to avoid pile-up effects during high charge operations.

  20. FIRST EXPERIMENTAL RESULTS FROM DEGAS, THE QUANTUM LIMITED BRIGHTNESS ELECTRON SOURCE

    International Nuclear Information System (INIS)

    Zolotorev, Max S.; Commins, Eugene D.; Oneill, James; Sannibale, Fernando; Tremsin, Anton; Wan, Weishi

    2008-01-01

    The construction of DEGAS (DEGenerate Advanced Source), a proof of principle for a quantum limited brightness electron source, has been completed at the Lawrence Berkeley National Laboratory. The commissioning and the characterization of this source, designed to generate coherent single electron 'bunches' with brightness approaching the quantum limit at a repetition rate of few MHz, has been started. In this paper the first experimental results are described

  1. Generation of high brightness ion beam from insulated anode PED

    International Nuclear Information System (INIS)

    Matsukawa, Yoshinobu

    1988-01-01

    Generation and focusing of a high density ion beam with high brightness from a organic center part of anode of a PED was reported previously. Mass, charge and energy distribution of this beam were analyzed. Three kind of anode were tried. Many highly ionized medium mass ions (up to C 4+ , O 6+ ) accelarated to several times of voltage difference between anode and cathode were observed. In the case of all insulator anode the current carried by the medium mass ions is about half of that carried by protons. (author)

  2. Working group II report: Production and dynamics of high brightness beams

    International Nuclear Information System (INIS)

    Sheffield, R.L.

    1996-01-01

    This paper summarizes the main discussions of the Working Group on the Production and Dynamics of High Brightness Beams. The following topics are covered in this paper. Proposed new electron sources and needed research on existing sources is covered. The discussions on issues relating to the description of phase space on non-thermalized electron beam distributions and the theoretical modeling on non-thermalized electron beam distributions is presented. Finally, the present status of the theoretical modeling of beam transport in bends is given

  3. Three-dimensional analysis of free-electron laser performance using brightness scaled variables

    Directory of Open Access Journals (Sweden)

    M. Gullans

    2008-06-01

    Full Text Available A three-dimensional analysis of radiation generation in a free-electron laser (FEL is performed in the small signal regime. The analysis includes beam conditioning, harmonic generation, flat beams, and a new scaling of the FEL equations using the six-dimensional beam brightness. The six-dimensional beam brightness is an invariant under Liouvillian flow; therefore, any nondissipative manipulation of the phase space, performed, for example, in order to optimize FEL performance, must conserve this brightness. This scaling is more natural than the commonly used scaling with the one-dimensional growth rate. The brightness-scaled equations allow for the succinct characterization of the optimal FEL performance under various additional constraints. The analysis allows for the simple evaluation of gain enhancement schemes based on beam phase space manipulations such as emittance exchange and conditioning. An example comparing the gain in the first and third harmonics of round or flat and conditioned or unconditioned beams is presented.

  4. HIGH ENERGY, HIGH BRIGHTNESS X-RAYS PRODUCED BY COMPTON BACKSCATTERING AT THE LIVERMORE PLEIADES FACILITY

    International Nuclear Information System (INIS)

    Tremaine, A M; Anderson, S G; Betts, S; Crane, J; Gibson, D J; Hartemann, F V; Jacob, J S; Frigola, P; Lim, J; Rosenzweig, J; Travish, G

    2005-01-01

    PLEIADES (Picosecond Laser Electron Interaction for the Dynamic Evaluation of Structures) produces tunable 30-140 keV x-rays with 0.3-5 ps pulse lengths and up to 10 7 photons/pulse by colliding a high brightness electron beam with a high power laser. The electron beam is created by an rf photo-injector system, accelerated by a 120 MeV linac, and focused to 20 (micro)m with novel permanent magnet quadrupoles. To produce Compton back scattered x-rays, the electron bunch is overlapped with a Ti:Sapphire laser that delivers 500 mJ, 100 fs, pulses to the interaction point. K-edge radiography at 115 keV on Uranium has verified the angle correlated energy spectrum inherent in Compton scattering and high-energy tunability of the Livermore source. Current upgrades to the facility will allow laser pumping of targets synchronized to the x-ray source enabling dynamic diffraction and time-resolved studies of high Z materials. Near future plans include extending the radiation energies to >400 keV, allowing for nuclear fluorescence studies of materials

  5. Variations in energy, flux, and brightness of pulsating aurora measured at high time resolution

    Directory of Open Access Journals (Sweden)

    H. Dahlgren

    2017-03-01

    Full Text Available High-resolution multispectral optical and incoherent scatter radar data are used to study the variability of pulsating aurora. Two events have been analysed, and the data combined with electron transport and ion chemistry modelling provide estimates of the energy and energy flux during both the ON and OFF periods of the pulsations. Both the energy and energy flux are found to be reduced during each OFF period compared with the ON period, and the estimates indicate that it is the number flux of foremost higher-energy electrons that is reduced. The energies are found never to drop below a few kilo-electronvolts during the OFF periods for these events. The high-resolution optical data show the occurrence of dips in brightness below the diffuse background level immediately after the ON period has ended. Each dip lasts for about a second, with a reduction in brightness of up to 70 % before the intensity increases to a steady background level again. A different kind of variation is also detected in the OFF period emissions during the second event, where a slower decrease in the background diffuse emission is seen with its brightness minimum just before the ON period, for a series of pulsations. Since the dips in the emission level during OFF are dependent on the switching between ON and OFF, this could indicate a common mechanism for the precipitation during the ON and OFF phases. A statistical analysis of brightness rise, fall, and ON times for the pulsations is also performed. It is found that the pulsations are often asymmetric, with either a slower increase of brightness or a slower fall.

  6. Criteria for emittance compensation in high-brightness photoinjectors

    Directory of Open Access Journals (Sweden)

    Chun-xi Wang

    2007-10-01

    Full Text Available A critical process in high-brightness photoinjectors is emittance compensation, which brings under control the correlated transverse emittance growth due to the linear space-charge force. Although emittance compensation has been used and studied for almost two decades, the exact criteria to achieve emittance compensation is not as clear as it should be. In this paper, a perturbative analysis of slice envelopes and emittance evolution close to any reference envelope is developed, via which space-charge and chromatic effects are investigated. A new criterion for emittance compensation is found, which is complementary to the well-known matching condition for the invariant envelope and agrees very well with simulations.

  7. Beam position monitors for the high brightness lattice

    International Nuclear Information System (INIS)

    Ring, T.

    1985-06-01

    Engineering developments associated with the high brightness lattice and the projected change in machine operating parameters will inherently affect the diagnostics systems and devices installed at present in the storage ring. This is particularly true of the beam position monitoring (BPI) system. The new sixteen unit cell lattice with its higher betatron tune values and the limited space available in the redesigned machine straights for fitting standard BPI vessels forces a fundamental re-evaluation of the beam position monitor system. The design aims for the new system are based on accepting the space limitations imposed while still providing the monitor points required to give good radial and vertical closed orbit plots. The locations of BPI's in the redesigned machine straights is illustrated. A description of the new BPI assemblies and their calibration is given. The BPI's use capacitance button type pick-ups; their response is described. (U.K.)

  8. Dynamics of annular bright field imaging in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Findlay, S.D.; Shibata, N.; Sawada, H.; Okunishi, E.; Kondo, Y.; Ikuhara, Y.

    2010-01-01

    We explore the dynamics of image formation in the so-called annular bright field mode in scanning transmission electron microscopy, whereby an annular detector is used with detector collection range lying within the cone of illumination, i.e. the bright field region. We show that this imaging mode allows us to reliably image both light and heavy columns over a range of thickness and defocus values, and we explain the contrast mechanisms involved. The role of probe and detector aperture sizes is considered, as is the sensitivity of the method to intercolumn spacing and local disorder.

  9. Proceedings of the third ICFA mini-workshop on high intensity, high brightness hadron accelerators

    International Nuclear Information System (INIS)

    Roser, T.

    1997-01-01

    The third mini-workshop on high intensity, high brightness hadron accelerators was held at Brookhaven National Laboratory on May 7-9, 1997 and had about 30 participants. The workshop focussed on rf and longitudinal dynamics issues relevant to intense and/or bright hadron synchrotrons. A plenary session was followed by four sessions on particular topics. This document contains copies of the viewgraphs used as well as summaries written by the session chairs

  10. Bright luminance from silicon dioxide film with carbon nanotube electron beam exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su Woong; Hong, Ji Hwan; Kang, Jung Su; Callixte, Shikili; Park, Kyu Chang, E-mail: kyupark@khu.ac.kr

    2016-02-15

    We observed the bright bluish-white luminescence with naked eye from carbon nanotube electron beam exposed silicon dioxide (SiO{sub 2}) thin film on Si substrate. The luminescence shows a peak intensity at 2.7 eV (460 nm) with wide spread up to 600 nm after the C-beam exposed on SiO{sub 2} thin film. The C-beam exposure system is composed of carbon nanotube emitters as electron beam source. The brightness strongly depend on the exposure condition. Luminescence characteristic was optimized by C-beam adjustment to observe with the naked eye. The cause of luminescence in the C-beam exposed SiO{sub 2} thin film is analyzed by CL microscopy, FT-IR, AFM and ellipsometer. Decrease of Si–O bonding was observed after C-beam exposure, and this reveals that oxygen deficient defects which are irradiation-sensitive cause 2.7 eV peak of luminescence. - Highlights: • We observed bright luminescence for SiO{sub 2} thin film with naked eye by carbon nanotube electron beam (C-beam) exposure technique. • The bright luminance from C-beam exposed SiO{sub 2} film will open novel silicon optoelectronics.

  11. Low Cost Lithography Tool for High Brightness LED Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Hawryluk; Emily True

    2012-06-30

    The objective of this activity was to address the need for improved manufacturing tools for LEDs. Improvements include lower cost (both capital equipment cost reductions and cost-ofownership reductions), better automation and better yields. To meet the DOE objective of $1- 2/kilolumen, it will be necessary to develop these highly automated manufacturing tools. Lithography is used extensively in the fabrication of high-brightness LEDs, but the tools used to date are not scalable to high-volume manufacturing. This activity addressed the LED lithography process. During R&D and low volume manufacturing, most LED companies use contact-printers. However, several industries have shown that these printers are incompatible with high volume manufacturing and the LED industry needs to evolve to projection steppers. The need for projection lithography tools for LED manufacturing is identified in the Solid State Lighting Manufacturing Roadmap Draft, June 2009. The Roadmap states that Projection tools are needed by 2011. This work will modify a stepper, originally designed for semiconductor manufacturing, for use in LED manufacturing. This work addresses improvements to yield, material handling, automation and throughput for LED manufacturing while reducing the capital equipment cost.

  12. High Brightness Neutron Source for Radiography. Final report

    International Nuclear Information System (INIS)

    Cremer, J.T.; Piestrup, Melvin A.; Gary, Charles K.; Harris, Jack L.; Williams, David J.; Jones, Glenn E.; Vainionpaa, J.H.; Fuller, Michael J.; Rothbart, George H.; Kwan, J.W.; Ludewigt, B.A.; Gough, R.A.; Reijonen, Jani; Leung, Ka-Ngo

    2008-01-01

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  13. Modeling of Diamond Field-Emitter-Arrays for high brightness photocathode applications

    Science.gov (United States)

    Kwan, Thomas; Huang, Chengkun; Piryatinski, Andrei; Lewellen, John; Nichols, Kimberly; Choi, Bo; Pavlenko, Vitaly; Shchegolkov, Dmitry; Nguyen, Dinh; Andrews, Heather; Simakov, Evgenya

    2017-10-01

    We propose to employ Diamond Field-Emitter-Arrays (DFEAs) as high-current-density ultra-low-emittance photocathodes for compact laser-driven dielectric accelerators capable of generating ultra-high brightness electron beams for advanced applications. We develop a semi-classical Monte-Carlo photoemission model for DFEAs that includes carriers' transport to the emitter surface and tunneling through the surface under external fields. The model accounts for the electronic structure size quantization affecting the transport and tunneling process within the sharp diamond tips. We compare this first principle model with other field emission models, such as the Child-Langmuir and Murphy-Good models. By further including effects of carrier photoexcitation, we perform simulations of the DFEAs' photoemission quantum yield and the emitted electron beam. Details of the theoretical model and validation against preliminary experimental data will be presented. Work ssupported by LDRD program at LANL.

  14. High Brightness HDR Projection Using Dynamic Freeform Lensing

    KAUST Repository

    Damberg, Gerwin

    2016-05-03

    Cinema projectors need to compete with home theater displays in terms of image quality. High frame rate and spatial resolution as well as stereoscopic 3D are common features today, but even the most advanced cinema projectors lack in-scene contrast and, more important, high peak luminance, both of which are essential perceptual attributes of images appearing realistic. At the same time, HDR image statistics suggest that the average image intensity in a controlled ambient viewing environment such as the cinema can be as low as 1% for cinematic HDR content and not often higher than 18%, middle gray in photography. Traditional projection systems form images and colors by blocking the source light from a lamp, therefore attenuating between 99% and 82% of light, on average. This inefficient use of light poses significant challenges for achieving higher peak brightness levels. In this work, we propose a new projector architecture built around commercially available components, in which light can be steered to form images. The gain in system efficiency significantly reduces the total cost of ownership of a projector (fewer components and lower operating cost), and at the same time increases peak luminance and improves black level beyond what is practically achievable with incumbent projector technologies. At the heart of this computational display technology is a new projector hardware design using phase modulation in combination with a new optimization algorithm that is capable of on-the-fly computation of freeform lens surfaces. © 2016 ACM.

  15. A MULTIWAVELENGTH STUDY OF THE HIGH SURFACE BRIGHTNESS HOT SPOT IN PKS 1421-490

    International Nuclear Information System (INIS)

    Godfrey, L. E. H.; Bicknell, G. V.; Lovell, J. E. J.; Jauncey, D. L.; Gelbord, J.; Schwartz, D. A.; Birkinshaw, M.; Worrall, D. M.; Marshall, H. L.; Georganopoulos, M.; Perlman, E. S.; Murphy, D. W.

    2009-01-01

    Long Baseline Array imaging of the z = 0.663 broadline radio galaxy PKS 1421-490 reveals a 400 pc diameter high surface brightness hot spot at a projected distance of ∼40 kpc from the active galactic nucleus. The isotropic X-ray luminosity of the hot spot, L 2-10keV = 3 x 10 44 ergs s -1 , is comparable to the isotropic X-ray luminosity of the entire X-ray jet of PKS 0637-752, and the peak radio surface brightness is hundreds of times greater than that of the brightest hot spot in Cygnus A. We model the radio to X-ray spectral energy distribution using a one-zone synchrotron self-Compton model with a near equipartition magnetic field strength of 3 mG. There is a strong brightness asymmetry between the approaching and receding hotspots and the hot spot spectrum remains flat (α ∼ 0.5) well beyond the predicted cooling break for a 3 mG magnetic field, indicating that the hotspot emission may be Doppler beamed. A high plasma velocity beyond the terminal jet shock could be the result of a dynamically important magnetic field in the jet. There is a change in the slope of the hotspot radio spectrum at GHz frequencies, which we model by incorporating a cutoff in the electron energy distribution at γ min ∼ 650, with higher values implied if the hotspot emission is Doppler beamed. We show that a sharp decrease in the electron number density below a Lorentz factor of 650 would arise from the dissipation of bulk kinetic energy in an electron/proton jet with a Lorentz factor Γ jet ∼> 5.

  16. Fabrication of bright and thin Zn₂SiO₄ luminescent film for electron beam excitation-assisted optical microscope.

    Science.gov (United States)

    Furukawa, Taichi; Kanamori, Satoshi; Fukuta, Masahiro; Nawa, Yasunori; Kominami, Hiroko; Nakanishi, Yoichiro; Sugita, Atsushi; Inami, Wataru; Kawata, Yoshimasa

    2015-07-13

    We fabricated a bright and thin Zn₂SiO₄ luminescent film to serve as a nanometric light source for high-spatial-resolution optical microscopy based on electron beam excitation. The Zn₂SiO₄ luminescent thin film was fabricated by annealing a ZnO film on a Si₃N₄ substrate at 1000 °C in N₂. The annealed film emitted bright cathodoluminescence compared with the as-deposited film. The film is promising for nano-imaging with electron beam excitation-assisted optical microscopy. We evaluated the spatial resolution of a microscope developed using this Zn₂SiO₄ luminescent thin film. This is the first report of the investigation and application of ZnO/Si₃N₄ annealed at a high temperature (1000 °C). The fabricated Zn₂SiO₄ film is expected to enable high-frame-rate dynamic observation with ultra-high resolution using our electron beam excitation-assisted optical microscopy.

  17. High brightness--multiple beamlets source for patterned X-ray production

    Science.gov (United States)

    Leung, Ka-Ngo [Hercules, CA; Ji, Qing [Albany, CA; Barletta, William A [Oakland, CA; Jiang, Ximan [El Cerrito, CA; Ji, Lili [Albany, CA

    2009-10-27

    Techniques for controllably directing beamlets to a target substrate are disclosed. The beamlets may be either positive ions or electrons. It has been shown that beamlets may be produced with a diameter of 1 .mu.m, with inter-aperture spacings of 12 .mu.m. An array of such beamlets, may be used for maskless lithography. By step-wise movement of the beamlets relative to the target substrate, individual devices may be directly e-beam written. Ion beams may be directly written as well. Due to the high brightness of the beamlets from extraction from a multicusp source, exposure times for lithographic exposure are thought to be minimized. Alternatively, the beamlets may be electrons striking a high Z material for X-ray production, thereafter collimated to provide patterned X-ray exposures such as those used in CAT scans. Such a device may be used for remote detection of explosives.

  18. High brightness diode lasers controlled by volume Bragg gratings

    Science.gov (United States)

    Glebov, Leonid

    2017-02-01

    Volume Bragg gratings (VBGs) recorded in photo-thermo-refractive (PTR) glass are holographic optical elements that are effective spectral and angular filters withstanding high power laser radiation. Reflecting VBGs are narrow-band spectral filters while transmitting VBGs are narrow-band angular filters. The use of these optical elements in external resonators of semiconductor lasers enables extremely resonant feedback that provides dramatic spectral and angular narrowing of laser diodes radiation without significant power and efficiency penalty. Spectral narrowing of laser diodes by reflecting VBGs demonstrated in wide spectral region from near UV to 3 μm. Commercially available VBGs have spectral width ranged from few nanometers to few tens of picometers. Efficient spectral locking was demonstrated for edge emitters (single diodes, bars, modules, and stacks), vertical cavity surface emitting lasers (VCSELs), grating coupled surface emitting lasers (GCSELs), and interband cascade lasers (ICLs). The use of multiplexed VBGs provides multiwavelength emission from a single emitter. Spectrally locked semiconductor lasers demonstrated CW power from milliwatts to a kilowatt. Angular narrowing by transmitting VBGs enables single transverse mode emission from wide aperture diode lasers having resonators with great Fresnel numbers. This feature provides close to diffraction limit divergence along a slow axis of wide stripe edge emitters. Radiation exchange between lasers by means of spatially profiled or multiplexed VBGs enables coherent combining of diode lasers. Sequence of VBGs or multiplexed VBGs enable spectral combining of spectrally narrowed diode lasers or laser modules. Thus the use of VBGs for diode lasers beam control provides dramatic increase of brightness.

  19. Simple, compact, high brightness source for x-ray lithography and x-ray radiography

    International Nuclear Information System (INIS)

    Hawryluk, A.M.

    1986-01-01

    A simple, compact, high brightness x-ray source has recently been built. This source utilizes a commercially available, cylindrical geometry electron beam evaporator, which has been modified to enhance the thermal cooling to the anode. Cooling is accomplished by using standard, low-conductivity laboratory water, with an inlet pressure of less than 50 psi, and a flow rate of approx.0.3 gal/min. The anode is an inverted cone geometry for efficient cooling. The x-ray source has a measured sub-millimeter spot size (FWHM). The anode has been operated at 1 KW e-beam power (10 KV, 100 ma). Higher operating levels will be investigated. A variety of different x-ray lines can be obtained by the simple interchange of anodes of different materials. Typical anodes are made from easily machined metals, or materials which are vacuum deposited onto a copper anode. Typically, a few microns of material is sufficient to stop 10 KV electrons without significantly decreasing the thermal conductivity through the anode. The small size and high brightness of this source make it useful for step and repeat exposures over several square centimeter areas, especially in a research laboratory environment. For an aluminum anode, the estimated Al-K x-ray flux at 10 cms from the source is 70 μW/cm 2

  20. An Ultra-Bright Pulsed Electron Beam with Low Longitudinal Emittance

    CERN Document Server

    Zolotorev, Max S; Denes, Peter; Heifets, Samuel; Hussain, Zahid; Lebedev, Gennadi; Lidia, Steven M; Robin, David; Sannibale, Fernando; Schönlein, Robert W; Vogel, Robert; Wan, Weishi

    2005-01-01

    We describe a novel scheme for an electron source in the 10 - 100 eV range with the capability of approaching the brightness quantum-limit and of lowering the effective temperature of the electrons orders of magnitude with respect to existing sources. Such a device can open the way for a wide range of novel applications that utilize angstrom-scale spatial resolution and ?eV-scale energy resolution. Possible examples include electron microscopy, electron holography, and investigations of dynamics on a picosecond time scale using pump-probe techniques. In this paper we describe the concepts for such a source including a complete and consistent set of parameters for the construction of a real device based on the presented scheme.

  1. High-brightness tapered laser diodes with photonic crystal structures

    Science.gov (United States)

    Li, Yi; Du, Weichuan; Kun, Zhou; Gao, Songxin; Ma, Yi; Tang, Chun

    2018-02-01

    Beam quality of tapered laser diodes is limited by higher order lateral mode. On purpose of optimizing the brightness of tapered laser diodes, we developed a novel design of tapered diodes. This devices based on InGaAs/AlGaAs asymmetry epitaxial structure, containing higher order lateral mode filtering schemes especially photonic crystal structures, which fabricated cost effectively by using standard photolithography and dry etch processes. Meanwhile, the effects of photonic crystal structures on mode control are also investigated theoretically by FDBPM (Finite-Difference Beam Propagation Method) calculation. We achieved a CW optical output power of 6.9W at 940nm for a single emitter with 4 mm cavity length. A nearly diffraction limited beam of M2 ≍1.9 @ 0.5W has been demonstrated, and a highest brightness of β =75MW/(cm2 ·sr) was reached.

  2. Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

    International Nuclear Information System (INIS)

    Anderson, S.G.; Barty, C.P.J.; Betts, S.M.; Brown, W.J.; Crane, J.K.; Cross, R.R.; Fittinghoff, D.N.; Gibson, D.J.; Hartemann, F.V.; Kuba, J.; LaSage, G.P.; Rosenzweig, J.B.; Slaughter, D.R.; Springer, P.T.; Tremaine, A.M.

    2003-01-01

    We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10 20 photons/s/0.1% bandwidth/mm 2 /mrad 2 . Initial results are reported and compared to theoretical calculations

  3. Highly modular high-brightness diode laser system design for a wide application range

    Science.gov (United States)

    Fritsche, Haro; Kruschke, Bastian; Koch, Ralf; Ferrario, Fabio; Kern, Holger; Pahl, Ullrich; Ehm, Einar; Pflueger, Silke; Grohe, Andreas; Gries, Wolfgang

    2015-03-01

    For an economic production it is important to serve as many applications as possible while keeping the product variations minimal. We present our modular laser design, which is based on single emitters and various combining technics. In a first step we accept a reduction of the very high brightness of the single emitters by vertical stacking. Those emitters can be wavelength stabilized by an external resonator, providing the very same feedback to each of those laser diodes which leads to an output power of about 100W with BPP of BPP. These "500W building blocks" are consequently designed in a way that without any system change new wavelengths can be implemented by only exchanging parts but without change of the production process. This design principal offers the option to adapt the wavelength of those blocks to any applications, from UV, visible into the far IR. From laser pumping and scientific applications to materials processing such as cutting and welding of copper aluminum or steel and also medical application. Operating at wavelengths between 900 nm and 1100 nm, these systems are mainly used in cutting and welding, but the technology can also be adapted to other wavelength ranges, such as 793 nm and 1530 nm. Around 1.5 μm the diodes are already successfully used for resonant pumping of Erbium lasers.[1] Furthermore, the fully integrated electronic concept allows addressing further applications, as it is capable of very short μs pulses up to cw mode operation by simple software commands.

  4. High brightness potassium ion gun for the HIF neutralized transport experiment (NTX)

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.; Roy, P.K.; Yu, S.S.

    2003-01-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. To focus a high intensity beam to a small spot requires a high brightness beam. In the NTX experiment, a potassium ion beam of up to 400 keV and 80 mA is generated in a Pierce type diode. At the diode exit, an aperture with variable size provides the capability to vary the beam perveance and to significantly reduce the beam emittance. We shall report on the gun characterization including current density profile, phase space distributions and the control of electrons generated by the beam scraping at the aperture. Comparison with particle simulations using the EGUN code will be presented

  5. Ultra-bright and highly efficient inorganic based perovskite light-emitting diodes

    Science.gov (United States)

    Zhang, Liuqi; Yang, Xiaolei; Jiang, Qi; Wang, Pengyang; Yin, Zhigang; Zhang, Xingwang; Tan, Hairen; Yang, Yang (Michael); Wei, Mingyang; Sutherland, Brandon R.; Sargent, Edward H.; You, Jingbi

    2017-06-01

    Inorganic perovskites such as CsPbX3 (X=Cl, Br, I) have attracted attention due to their excellent thermal stability and high photoluminescence quantum efficiency. However, the electroluminescence quantum efficiency of their light-emitting diodes was CsPbBr3 lattice and by depositing a hydrophilic and insulating polyvinyl pyrrolidine polymer atop the ZnO electron-injection layer to overcome these issues. As a result, we obtained light-emitting diodes exhibiting a high brightness of 91,000 cd m-2 and a high external quantum efficiency of 10.4% using a mixed-cation perovskite Cs0.87MA0.13PbBr3 as the emitting layer. To the best of our knowledge, this is the brightest and most-efficient green perovskite light-emitting diodes reported to date.

  6. Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

    Science.gov (United States)

    Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

    2015-11-17

    We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

  7. High cortisol awakening response is associated with an impairment of the effect of bright light therapy

    DEFF Research Database (Denmark)

    Martiny, Klaus Per Juul; Lunde, Marianne Anita; Undén, M

    2009-01-01

    OBJECTIVE: We investigated the predictive validity of the cortisol awakening response (CAR) in patients with non-seasonal major depression. METHOD: Patients were treated with sertraline in combination with bright or dim light therapy for a 5-week period. Saliva cortisol levels were measured in 63...... patients, as an awakening profile, before medication and light therapy started. The CAR was calculated by using three time-points: awakening and 20 and 60 min after awakening. RESULTS: Patients with low CAR had a very substantial effect of bright light therapy compared with dim light therapy, whereas...... patients with a high CAR had no effect of bright light therapy compared with dim light therapy. CONCLUSION: High CAR was associated with an impairment of the effect of bright light therapy. This result raises the question of whether bright light acts through a mechanism different from...

  8. Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Anatoly Shteynberg, PhD

    2006-08-17

    This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.

  9. The High Luminosity Challenge: potential and limitations of High Intensity High Brightness in the LHC and its injectors

    CERN Document Server

    De Maria, R; Banfi, D; Barranco, J; Bartosik, H; Benedetto, E; Bruce, R; Brüning, O; Calaga, R; Cerutti, F; Damerau, H; Esposito, L; Fartoukh, S; Fitterer, M; Garoby, R; Gilardoni, S; Giovannozzi, M; Goddard, B; Gorini, B; Hanke, K; Iadarola, G; Lamont, M; Meddahi, M; Métral, E; Mikulec, B; Mounet, N; Papaphilippou, Y; Pieloni, T; Redaelli, S; Rossi, L; Rumolo, G; Shaposhnikova, E; Sterbini, G; Todesco, E; Tomás, R; Zimmermann, F; Valishev, A

    2014-01-01

    High-intensity and high-brightness beams are key ingredients to maximize the LHC integrated luminosity and to exploit its full potential. This contribution describes the optimization of beam and machine parameters to maximize the integrated luminosity as seen by the LHC experiments, by taking into account the expected intensity and brightness reach of LHC itself and its injector chain as well as the capabilities of the detectors for next run and foreseen upgrade scenarios.

  10. Design of a high-power, high-brightness Nd:YAG solar laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana; Garcia, Dário

    2014-03-20

    A simple high-power, high-brightness Nd:YAG solar laser pumping approach is presented in this paper. The incoming solar radiation is both collected and concentrated by four Fresnel lenses and redirected toward a Nd:YAG laser head by four plane-folding mirrors. A fused-silica secondary concentrator is used to compress the highly concentrated solar radiation to a laser rod. Optimum pumping conditions and laser resonator parameters are found through ZEMAX and LASCAD numerical analysis. Solar laser power of 96 W is numerically calculated, corresponding to the collection efficiency of 24  W/m². A record-high solar laser beam brightness figure of merit of 9.6 W is numerically achieved.

  11. Numerical simulations of novel high-power high-brightness diode laser structures

    Science.gov (United States)

    Boucke, Konstantin; Rogg, Joseph; Kelemen, Marc T.; Poprawe, Reinhart; Weimann, Guenter

    2001-07-01

    One of the key topics in today's semiconductor laser development activities is to increase the brightness of high-power diode lasers. Although structures showing an increased brightness have been developed specific draw-backs of these structures lead to a still strong demand for investigation of alternative concepts. Especially for the investigation of basically novel structures easy-to-use and fast simulation tools are essential to avoid unnecessary, cost and time consuming experiments. A diode laser simulation tool based on finite difference representations of the Helmholtz equation in 'wide-angle' approximation and the carrier diffusion equation has been developed. An optimized numerical algorithm leads to short execution times of a few seconds per resonator round-trip on a standard PC. After each round-trip characteristics like optical output power, beam profile and beam parameters are calculated. A graphical user interface allows online monitoring of the simulation results. The simulation tool is used to investigate a novel high-power, high-brightness diode laser structure, the so-called 'Z-Structure'. In this structure an increased brightness is achieved by reducing the divergency angle of the beam by angular filtering: The round trip path of the beam is two times folded using internal total reflection at surfaces defined by a small index step in the semiconductor material, forming a stretched 'Z'. The sharp decrease of the reflectivity for angles of incidence above the angle of total reflection leads to a narrowing of the angular spectrum of the beam. The simulations of the 'Z-Structure' indicate an increase of the beam quality by a factor of five to ten compared to standard broad-area lasers.

  12. High spatial resolution and high brightness ion beam probe for in-situ elemental and isotopic analysis

    Science.gov (United States)

    Long, Tao; Clement, Stephen W. J.; Bao, Zemin; Wang, Peizhi; Tian, Di; Liu, Dunyi

    2018-03-01

    A high spatial resolution and high brightness ion beam from a cold cathode duoplasmatron source and primary ion optics are presented and applied to in-situ analysis of micro-scale geological material with complex structural and chemical features. The magnetic field in the source as well as the influence of relative permeability of magnetic materials on source performance was simulated using COMSOL to confirm the magnetic field strength of the source. Based on SIMION simulation, a high brightness and high spatial resolution negative ion optical system has been developed to achieve Critical (Gaussian) illumination mode. The ion source and primary column are installed on a new Time-of-Flight secondary ion mass spectrometer for analysis of geological samples. The diameter of the ion beam was measured by the knife-edge method and a scanning electron microscope (SEM). Results show that an O2- beam of ca. 5 μm diameter with a beam intensity of ∼5 nA and an O- beam of ca. 5 μm diameter with a beam intensity of ∼50 nA were obtained, respectively. This design will open new possibilities for in-situ elemental and isotopic analysis in geological studies.

  13. High brightness photonic band crystal semiconductor lasers in the passive mode locking regime

    Energy Technology Data Exchange (ETDEWEB)

    Rosales, R.; Kalosha, V. P.; Miah, M. J.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany); Posilović, K. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany); PBC Lasers GmbH, Hardenbergstrasse 36, 10623 Berlin (Germany); Pohl, J.; Weyers, M. [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany)

    2014-10-20

    High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm{sup −2} sr{sup −1} are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.

  14. High brightness photonic band crystal semiconductor lasers in the passive mode locking regime

    International Nuclear Information System (INIS)

    Rosales, R.; Kalosha, V. P.; Miah, M. J.; Bimberg, D.; Posilović, K.; Pohl, J.; Weyers, M.

    2014-01-01

    High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm −2  sr −1 are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.

  15. Theory of bright-field scanning transmission electron microscopy for tomography

    International Nuclear Information System (INIS)

    Levine, Zachary H.

    2005-01-01

    Radiation transport theory is applied to electron microscopy of samples composed of one or more materials. The theory, originally due to Goudsmit and Saunderson, assumes only elastic scattering and an amorphous medium dominated by atomic interactions. For samples composed of a single material, the theory yields reasonable parameter-free agreement with experimental data taken from the literature for the multiple scattering of 300-keV electrons through aluminum foils up to 25 μm thick. For thin films, the theory gives a validity condition for Beer's law. For thick films, a variant of Moliere's theory [V. G. Moliere, Z. Naturforschg. 3a, 78 (1948)] of multiple scattering leads to a form for the bright-field signal for foils in the multiple-scattering regime. The signal varies as [t ln(e 1-2γ t/τ)] -1 where t is the path length of the beam, τ is the mean free path for elastic scattering, and γ is Euler's constant. The Goudsmit-Saunderson solution interpolates numerically between these two limits. For samples with multiple materials, elemental sensitivity is developed through the angular dependence of the scattering. From the elastic scattering cross sections of the first 92 elements, a singular-value decomposition of a vector space spanned by the elastic scattering cross sections minus a delta function shows that there is a dominant common mode, with composition-dependent corrections of about 2%. A mathematically correct reconstruction procedure beyond 2% accuracy requires the acquisition of the bright-field signal as a function of the scattering angle. Tomographic reconstructions are carried out for three singular vectors of a sample problem with four elements Cr, Cu, Zr, and Te. The three reconstructions are presented jointly as a color image; all four elements are clearly identifiable throughout the image

  16. High-brightness high-order harmonic generation at 13 nm with a long gas jet

    International Nuclear Information System (INIS)

    Kim, Hyung Taek; Kim, I Jong; Lee, Dong Gun; Park, Jong Ju; Hong, Kyung Han; Nam, Chang Hee

    2002-01-01

    The generation of high-order harmonics is well-known method producing coherent extreme-ultraviolet radiation with pulse duration in the femtosecond regime. High-order harmonics have attracted much attention due to their unique features such as coherence, ultrashort pulse duration, and table-top scale system. Due to these unique properties, high-order harmonics have many applications of atomic and molecular spectroscopy, plasma diagnostics and solid-state physics. Bright generation of high-order harmonics is important for actual applications. Especially, the generation of strong well-collimated harmonics at 13 nm can be useful for the metrology of EUV lithography optics because of the high reflectivity of Mo-Si mirrors at this wavelength. The generation of bright high-order harmonics is rather difficult in the wavelength region below 15nm. Though argon and xenon gases have large conversion efficiency, harmonic generation from these gases is restricted to wavelengths over 20 nm due to low ionization potential. Hence, we choose neon for the harmonic generation around 13 nm; it has larger conversion efficiency than helium and higher ionization potential than argon. In this experiment, we have observed enhanced harmonic generation efficiency and low beam divergence of high-order harmonics from a elongated neon gas jet by the enhancement of laser propagation in an elongated gas jet. A uniform plasma column was produced when the gas jet was exposed to converging laser pulses.

  17. Characterizing the Motion of Solar Magnetic Bright Points at High Resolution

    Science.gov (United States)

    Van Kooten, Samuel J.; Cranmer, Steven R.

    2017-11-01

    Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power spectrum of Alfvén wave excitation, transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. We produce a power spectrum of bright-point motion using radiative magnetohydrodynamic simulations, exploiting spatial resolution higher than can be obtained in present-day observations, while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observation-based spectra, while confirming the spectrum shape of recent observations. This also provides a prediction for observations of bright points with DKIST, which will achieve similar resolution and high sensitivity. We also find a granule size distribution in support of an observed two-population distribution, and we present results from tracking passive tracers, which show a similar power spectrum to that of bright points. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright-point motion.

  18. Los Alamos High-Brightness Accelerator FEL (HIBAF) facility

    Energy Technology Data Exchange (ETDEWEB)

    Cornelius, W.D.; Bender, S.; Meier, K.; Thode, L.E.; Watson, J.M.

    1989-01-01

    The 10-/mu/m Los Alamos free-electron laser (FEL) facility is being upgraded. The conventional electron gun and bunchers have been replaced with a much more compact 6-MeV photoinjector accelerator. By adding existing parts from previous experiments, the primary beam energy will be doubled to 40 MeV. With the existing 1-m wiggler (/lambda//sub w/ = 2.7 cm) and resonator, the facility can produce photons with wavelengths from 3 to 100 /mu/m when lasing on the fundamental mode and produce photons in the visible spectrum with short-period wigglers or harmonic operation. After installation of a 150/degree/ bend, a second wiggler will be added as an amplifier. The installation of laser transport tubes between the accelerator vault and an upstairs laboratory will provide experimenters with a radiation-free environment for experiments. Although the initial experimental program of the upgraded facility will be to test the single accelerator-master oscillator/power amplifier configuration, some portion of the operational time of the facility can be dedicated to user experiments. 13 refs., 5 figs., 6 tabs.

  19. Production of quasi ellipsoidal laser pulses for next generation high brightness photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Rublack, T., E-mail: Tino.Rublack@desy.de [DESY, Zeuthen (Germany); Good, J.; Khojoyan, M.; Krasilnikov, M.; Stephan, F. [DESY, Zeuthen (Germany); Hartl, I.; Schreiber, S. [DESY, Hamburg (Germany); Andrianov, A.; Gacheva, E.; Khazanov, E.; Mironov, S.; Potemkin, A.; Zelenogorskii, V.V. [IAP/RAS, Nizhny Novgorod (Russian Federation); Syresin, E. [JINR, Dubna (Russian Federation)

    2016-09-01

    The use of high brightness electron beams in Free Electron Laser (FEL) applications is of increasing importance. One of the most promising methods to generate such beams is the usage of shaped photocathode laser pulses. It has already demonstrated that temporal and transverse flat-top laser pulses can produce very low emittance beams [1]. Nevertheless, based on beam simulations further improvements can be achieved using quasi-ellipsoidal laser pulses, e.g. 30% reduction in transverse projected emittance at 1 nC bunch charge. In a collaboration between DESY, the Institute of Applied Physics of the Russian Academy of Science (IAP RAS) in Nizhny Novgorod and the Joint Institute of Nuclear Research (JINR) in Dubna such a laser system capable of producing trains of laser pulses with a quasi-ellipsoidal distribution, has been developed. The prototype of the system was installed at the Photo Injector Test facility at DESY in Zeuthen (PITZ) and is currently in the commissioning phase. In the following, the laser system will be introduced, the procedure of pulse shaping will be described and the last experimental results will be shown.

  20. Toward high brightness, multi-kilowatt solid state lasers

    International Nuclear Information System (INIS)

    Zapata, L.E.; Manes, K.R.

    1990-11-01

    High average power (HAP) solid state laser output with improved beam quality has introduced new capabilities in materials processing. At the 500 W level and with a beam quality of a ''few'' times the diffraction limit, the General Electric NY slab is able to drill 5 cm of stainless steel in a few seconds. We expect that 2--3 kW of near infrared laser output in a low order spatial mode would enable metal working now unknown to industry. The HAP output of slab lasers is limited by the size of the available laser crystals and the pump power. Core free, six cm diameter NY boules have been grown on an experimental basis. High optical quality NG can be obtained up to 10 cm in diameter. We present the results of our modeling based on these crystals pumped by advanced arc-lamps or laser diode arrays. We project HAP laser outputs of 1.6 kW from an existing Vortek pumped NG oscillator and about 2 kW from diode pumped NY device. Several kW of laser output can be expected from two such slabs in a MOPA configuration before optical damage limits are reached. The three dimensional stress-optic code which we used to optimize our designs, was normalized to available experimental data obtained with the above NG slab at the 500 W level and a 40 W diode pumped NY test bed. Our calculations indicate the essential parameters for attainment of high beam quality. Cooling uniformity across the pumped faces of the slab is critical and the location of the transition between pumped and un-pumped regions towards the slab tips is very important. A flat pumping profile was found to be desirable and predicted one wave of distortion which should be correctable over about 75% of the aperture however, an even better wavefront was predicted over 90% of the aperture when the regions near the edges of the slab were slightly over-pumped relative to the central regions and the regions near to the ends were tapered to compensate for transition effects

  1. High brightness photonic lantern kW-class amplifier

    Science.gov (United States)

    Montoya, Juan; Hwang, Chris; Aleshire, Chris; Reed, Patricia; Martz, Dale; Riley, Mike; Trainor, Michael; Belley, Catherine; Shaw, Scot; Fan, T. Y.; Ripin, Dan

    2018-02-01

    Pump-limited kW-class operation in a multimode fiber amplifier using adaptive mode control was achieved. A photonic lantern front end was used to inject an arbitrary superposition of modes on the input to a kW-class fiber amplifier to achieve a nearly diffraction-limited output. We report on the adaptive spatial mode control architecture which allows for compensating transverse-mode disturbances at high power. We also describe the advantages of adaptive spatial mode control for optical phased array systems. In particular, we show that the additional degrees of freedom allow for broader steering and improved atmospheric turbulence compensation relative to piston-only optical phased arrays.

  2. High brightness diode-pumped organic solid-state laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhuang; Mhibik, Oussama; Nafa, Malik; Chénais, Sébastien; Forget, Sébastien, E-mail: sebastien.forget@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430, Villetaneuse (France); CNRS, UMR 7538, LPL, F-93430, Villetaneuse (France)

    2015-02-02

    High-power, diffraction-limited organic solid-state laser operation has been achieved in a vertical external cavity surface-emitting organic laser (VECSOL), pumped by a low-cost compact blue laser diode. The diode-pumped VECSOLs were demonstrated with various dyes in a polymer matrix, leading to laser emissions from 540 nm to 660 nm. Optimization of both the pump pulse duration and output coupling leads to a pump slope efficiency of 11% for a DCM based VECSOLs. We report output pulse energy up to 280 nJ with 100 ns long pump pulses, leading to a peak power of 3.5 W in a circularly symmetric, diffraction-limited beam.

  3. A new method to detect and correct sample tilt in scanning transmission electron microscopy bright-field imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brown, H.G. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Ishikawa, R.; Sánchez-Santolino, G. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Lugg, N.R., E-mail: shibata@sigma.t.u-tokyo.ac.jp [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Ikuhara, Y. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Allen, L.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Shibata, N. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan)

    2017-02-15

    Important properties of functional materials, such as ferroelectric shifts and octahedral distortions, are associated with displacements of the positions of lighter atoms in the unit cell. Annular bright-field scanning transmission electron microscopy is a good experimental method for investigating such phenomena due to its ability to image light and heavy atoms simultaneously. To map atomic positions at the required accuracy precise angular alignment of the sample with the microscope optical axis is necessary, since misalignment (tilt) of the specimen contributes to errors in position measurements of lighter elements in annular bright-field imaging. In this paper it is shown that it is possible to detect tilt with the aid of images recorded using a central bright-field detector placed within the inner radius of the annular bright-field detector. For a probe focus near the middle of the specimen the central bright-field image becomes especially sensitive to tilt and we demonstrate experimentally that misalignment can be detected with a precision of less than a milliradian, as we also confirm in simulation. Coma in the probe, an aberration that can be misidentified as tilt of the specimen, is also investigated and it is shown how the effects of coma and tilt can be differentiated. The effects of tilt may be offset to a large extent by shifting the diffraction plane detector an amount equivalent to the specimen tilt and we provide an experimental proof of principle of this using a segmented detector system. - Highlights: • Octahedral distortions are associated with displacements of lighter atoms. • Annular bright-field imaging is sensitive to light and heavy atoms simultaneously. • Mistilt of the specimen leads to errors in position measurements of lighter elements. • It is possible to detect tilt using images taken by a central bright-field detector. • Tilt may be offset by shifting the diffraction plane detector by an equivalent amount.

  4. Photocathodes inside superconducting cavities. Studies on the feasibility of a superconducting photoelectron source of high brightness. External report

    International Nuclear Information System (INIS)

    Michalke, A.

    1992-01-01

    We have done studies and experiments to explore the feasibility of a photoemission RF gun with a superconducting accelerator cavity. This concept promises to provide an electron beam of high brightness in continuous operation. It is thus of strong interest for a free-electron-laser or a linear collider based on a superconducting accelerator. In a first step we studied possible technical solutions for its components, especially the material of the photocathode and the geometrical shape of the cavity. Based on these considerations, we developed the complete design for a prototype electron source. The cathode material was chosen to be alkali antimonide. In spite of its sensitivity, it seems to be the best choice for a gun with high average current due to its high quantum efficiency. The cavity shape was at first a reentrant-type single cell of 500 MHz. It is now replaced by a more regular two-and-half cell shape, an independent half cell added for emittance correction. Its beam dynamics properties are investigated by numerical simulations; we estimated a beam brightness of about 5x10 11 A/(m.rad) 2 . But the mutual interactions between alkali antimonide photocathode and superconducting cavity must be investigated experimentally, because they are completely unkown. (orig.)

  5. High-brightness beamline for x-ray spectroscopy at the ALS

    Energy Technology Data Exchange (ETDEWEB)

    Perera, R.C.C.; Jones, G. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Lindle, D.W. [Univ. of Nevada, Las Vegas, NV (United States)

    1997-04-01

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard x-ray beamline, and its brightness will be an order of magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new {open_quotes}Cowan type{close_quotes} double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12 m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS.

  6. Impact of the ADT on the beam quality with high brightness beams in collision (MD2155)

    CERN Document Server

    Buffat, Xavier; Kostoglou, Sofia; Salvachua Ferrando, Belen Maria; Papadopoulou, Parthena Stefania; Ponce, Laurette; Solfaroli Camillocci, Matteo; Suykerbuyk, Ronaldus; Valuch, Daniel; Walsh, David John; Barranco Garcia, Javier; Pieloni, Tatiana; CERN. Geneva. ATS Department

    2018-01-01

    The results of an experiment aiming at determining indirectly the noise level in the LHC, isolating the contribution of the transverse damper, through their impact on the emittance of colliding high brightness bunches at 6.5 TeV in the LHC are presented.

  7. High-power electronics

    CERN Document Server

    Kapitsa, Petr Leonidovich

    1966-01-01

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

  8. Status of the C-band RF System for the SPARC-LAB high brightness photo-injector

    CERN Document Server

    Boni, R.; Bellaveglia, M.; Di Pirro, G.; Ferrario, M.; Gallo, A.; Spataro, B.; Mostacci, A.; Palumbo, L.

    2013-01-01

    The high brightness photo-injector in operation at the SPARC-LAB facility of the INFN-LNF, Italy, consists of a 150 MeV S-band electron accelerator aiming to explore the physics of low emittance high peak current electron beams and the related technology. Velocity bunching techniques, SASE and Seeded FEL experiments have been carried out successfully. To increase the beam energy so improving the performances of the experiments, it was decided to replace one S-band travelling wave accelerating cavity, with two C-band cavities that allow to reach higher energy gain per meter. The new C-band system is in advanced development phase and will be in operation early in 2013. The main technical issues of the C-band system and the R&D activities carried out till now are illustrated in detail in this paper.

  9. High-power fiber lasers for photocathode electron injectors

    Directory of Open Access Journals (Sweden)

    Zhi Zhao

    2014-05-01

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

  10. 980 nm high brightness external cavity broad area diode laser bar

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Thestrup Nielsen, Birgitte

    2009-01-01

    We demonstrate of-axis spectral beam combining applied to a 980 nm high power broad area diode laser bar. The experiments yielded 9 W of optical power at 30 A of operating current and the measured M2 values of the combined beam from 12 emitters were 1.9 and 6.4 for the fast and the slow axis......, respectively. The slow axis beam quality was 5-6 times better than the value obtained from a single emitter in free running mode. A high brightness of 79 MW/cm2-str was achieved using this configuration. To our knowledge, this is the highest brightness level ever achieved from a broad area diode laser bar....

  11. Extremely high-brightness kW-class fiber coupled diode lasers with wavelength stabilization

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Glenn, John D.

    2011-06-01

    TeraDiode has produced ultra-high brightness fiber-coupled direct diode lasers. A fiber-coupled direct diode laser with a power level of 1,040 W from a 200 μm core diameter, 0.18 numerical aperture (NA) output fiber at a single center wavelength was demonstrated. This was achieved with a novel beam combining and shaping technique using COTS diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 18 mm-mrad and is the lowest BPP kW-class direct diode laser yet reported. The laser has been used to demonstrate laser cutting and welding of steel sheet metal up to 6.65 mm thick. Higher brightness fiber-coupled diode lasers, including a module with 418 W of power coupled to a 100 μm, 0.15 NA fiber, have also been demonstrated.

  12. Arbitrarily shaped high-coherence electron bunches from cold atoms

    Science.gov (United States)

    McCulloch, A. J.; Sheludko, D. V.; Saliba, S. D.; Bell, S. C.; Junker, M.; Nugent, K. A.; Scholten, R. E.

    2011-10-01

    Ultrafast electron diffractive imaging of nanoscale objects such as biological molecules and defects in solid-state devices provides crucial information on structure and dynamic processes: for example, determination of the form and function of membrane proteins, vital for many key goals in modern biological science, including rational drug design. High brightness and high coherence are required to achieve the necessary spatial and temporal resolution, but have been limited by the thermal nature of conventional electron sources and by divergence due to repulsive interactions between the electrons, known as the Coulomb explosion. It has been shown that, if the electrons are shaped into ellipsoidal bunches with uniform density, the Coulomb explosion can be reversed using conventional optics, to deliver the maximum possible brightness at the target. Here we demonstrate arbitrary and real-time control of the shape of cold electron bunches extracted from laser-cooled atoms. The ability to dynamically shape the electron source itself and to observe this shape in the propagated electron bunch provides a remarkable experimental demonstration of the intrinsically high spatial coherence of a cold-atom electron source, and the potential for alleviation of electron-source brightness limitations due to Coulomb explosion.

  13. Advanced high brightness ion rf accelerator applications in the nuclear energy

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1991-01-01

    The capability of modern rf linear accelerators to provide intense high quality beams of protons, deuterons, or heavier ions is opening new possibilities for transmuting existing nuclear wastes, for generating electricity from readily available fuels with minimal residual wastes, for building intense neutron sources for materials research, for inertial confinement fusion using heavy ions, and for other new applications. These are briefly described, couched in a perspective of the advances in the understanding of the high brightness beams that has enabled these new programs. 32 refs., 2 figs

  14. Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

    Science.gov (United States)

    Manahan, G. G.; Habib, A. F.; Scherkl, P.; Delinikolas, P.; Beaton, A.; Knetsch, A.; Karger, O.; Wittig, G.; Heinemann, T.; Sheng, Z. M.; Cary, J. R.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

    2017-06-01

    Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m-1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread--an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wave can be locally overloaded without compromising the witness bunch normalized emittance. This reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams.

  15. Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Piochacz, Christian

    2009-11-20

    Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55{+-}0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 {mu}m. The efficiency of the re-moderation process in this second stage was 24.5{+-}4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the

  16. Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

    International Nuclear Information System (INIS)

    Piochacz, Christian

    2009-01-01

    Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55±0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 μm. The efficiency of the re-moderation process in this second stage was 24.5±4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the SPM

  17. A high brightness source for nano-probe secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, N.S. [Oregon Physics LLC, 2704 SE 39th Loop, Suite 109, Hillsboro, OR 97123 (United States)], E-mail: n.smith@oregon-physics.com; Tesch, P.P.; Martin, N.P.; Kinion, D.E. [Oregon Physics LLC, 2704 SE 39th Loop, Suite 109, Hillsboro, OR 97123 (United States)

    2008-12-15

    The two most prevalent ion source technologies in the field of surface analysis and surface machining are the Duoplasmatron and the liquid metal ion source (LMIS). There have been many efforts in this area of research to develop an alternative source [; N.S. Smith, W.P. Skoczylas, S.M. Kellogg, D.E. Kinion, P.P. Tesch, O. Sutherland, A. Aanesland, R.W. Boswell, J. Vac. Sci. Technol. B 24 (6) (2006) 2902-2906] with the brightness of a LMIS and yet the ability to produce secondary ion yield enhancing species such as oxygen. However, to date a viable alternative has not been realized. The high brightness and small virtual source size of the LMIS are advantageous for forming high resolution probes but a significant disadvantage when beam currents in excess of 100 nA are required, due to the effects of spherical aberration from the optical column. At these higher currents a source with a high angular intensity is optimal and in fact the relatively moderate brightness of today's plasma ion sources prevail in this operating regime. Both the LMIS and Duoplasmatron suffer from a large axial energy spread resulting in further limitations when forming focused beams at the chromatic limit where the figure-of-merit is inversely proportional to the square of the energy spread. Also, both of these ion sources operate with a very limited range of ion species. This article reviews some of the latest developments and some future potential in this area of instrument development. Here we present an approach to source development that could lead to oxygen ion beam SIMS imaging with 10 nm resolution, using a 'broad area' RF gas phase ion source.

  18. Plasma conditions generated by interaction of a high brightness, prepulse free Raman amplified KrF laser pulse with solid targets

    International Nuclear Information System (INIS)

    Riley, D.; Gizzi, L.A.; Khattak, F.Y.; Mackinnon, A.J.; Viana, S.M.; Willi, O.

    1992-01-01

    A high brightness, Raman amplified KrF laser has been used to irradiate solid targets with 12 ps laser pulses at intensities above 10 15 W/cm 2 without the presence of a preformed plasma caused by low level amplified spontaneous emission prepulse. Time-resolved x-ray spectroscopy of the K-shell emission from aluminum was used to infer electron densities in excess of 10 23 cm -3 at temperatures of several hundred electronvolts

  19. First results from the high-brightness x-ray spectroscopy beamline at ALS

    Energy Technology Data Exchange (ETDEWEB)

    Perera, R.C.C.; Ng, W.; Jones, G. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goal of high brightness at the sample for use in the X-ray Atomic and Molecular Spectroscopy (XAMS) science, surface and interface science, biology and x-ray optical development programs at ALS. X-ray absorption and time of flight photo emission measurements in 2 - 5 keV photon energy in argon along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

  20. InGaN micro-LED-pillar as the building block for high brightness emitters

    KAUST Repository

    Shen, Chao; Cha, Dong Kyu; Ng, Tien Khee; Ooi, Boon S.; Yang, Yang

    2013-01-01

    In summary, we confirmed the improved electrical and optical characteristics, with reduced efficiency droop in InGaN μLED-pillars when these devices were scaled down in size. We demonstrated that strain relief contributed to further improvement in EQE characteristics in small InGaN μLED-pillars (D < 50 μm), apart from the current spreading effect. The μLED-pillar can be deployed as the building block for large effective-area, high brightness emitter. © 2013 IEEE.

  1. High field electron linacs

    International Nuclear Information System (INIS)

    Le Duff, J.

    1985-12-01

    High field electron linacs are considered as potential candidates to provide very high energies beyond LEP. Since almost twenty years not much improvement has been made on linac technologies as they have been mostly kept at low and medium energies to be used as injectors for storage rings. Today, both their efficiency and their performances are being reconsidered, and for instance the pulse compression sheme developed at SLAC and introduced to upgrade the energy of that linac is a first step towards a new generation of linear accelerators. However this is not enough in terms of power consumption and more development is needed to improve both the efficiency of accelerating structures and the performances of RF power sources

  2. Modulational instability: Conservation laws and bright soliton solution of ion-acoustic waves in electron-positron-ion-dust plasmas

    Science.gov (United States)

    EL-Kalaawy, O. H.

    2018-02-01

    We consider the nonlinear propagation of non-planar (cylindrical and spherical) ion-acoustic (IA) envelope solitary waves in an unmagnetized plasma consisting of electron-positron-ion-dust plasma with two-electron temperature distributions in the context of the non-extensive statistics. The basic set of fluid equations is reduced to the modified nonlinear Schrödinger (MNLS) equation in cylindrical and spherical geometry by using the reductive perturbation method (RPM). It is found that the nature of the modulational instabilities would be significantly modified due to the effects of the non-extensive and other plasma parameters as well as cylindrical and spherical geometry. Conservation laws of the MNLS equation are obtained by Lie symmetry and multiplier method. A new exact solution (envelope bright soliton) is obtained by the extended homogeneous balance method. Finally, we study the results of this article.

  3. TH-CD-207B-01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple-Pixel X-Ray Source Using Oxide Coated Cathodes

    International Nuclear Information System (INIS)

    Kandlakunta, P; Pham, R; Zhang, T

    2016-01-01

    Purpose: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. Methods: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro-rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x-ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm 2 . The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x-ray measurements estimated the focal spot size as 1.5 × 1.3 mm 2 . Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x-ray beams with a fast switching speed.

  4. High-Brightness Blue Light-Emitting Diodes Enabled by a Directly Grown Graphene Buffer Layer.

    Science.gov (United States)

    Chen, Zhaolong; Zhang, Xiang; Dou, Zhipeng; Wei, Tongbo; Liu, Zhiqiang; Qi, Yue; Ci, Haina; Wang, Yunyu; Li, Yang; Chang, Hongliang; Yan, Jianchang; Yang, Shenyuan; Zhang, Yanfeng; Wang, Junxi; Gao, Peng; Li, Jinmin; Liu, Zhongfan

    2018-06-08

    Single-crystalline GaN-based light-emitting diodes (LEDs) with high efficiency and long lifetime are the most promising solid-state lighting source compared with conventional incandescent and fluorescent lamps. However, the lattice and thermal mismatch between GaN and sapphire substrate always induces high stress and high density of dislocations and thus degrades the performance of LEDs. Here, the growth of high-quality GaN with low stress and a low density of dislocations on graphene (Gr) buffered sapphire substrate is reported for high-brightness blue LEDs. Gr films are directly grown on sapphire substrate to avoid the tedious transfer process and GaN is grown by metal-organic chemical vapor deposition (MOCVD). The introduced Gr buffer layer greatly releases biaxial stress and reduces the density of dislocations in GaN film and In x Ga 1- x N/GaN multiple quantum well structures. The as-fabricated LED devices therefore deliver much higher light output power compared to that on a bare sapphire substrate, which even outperforms the mature process derived counterpart. The GaN growth on Gr buffered sapphire only requires one-step growth, which largely shortens the MOCVD growth time. This facile strategy may pave a new way for applications of Gr films and bring several disruptive technologies for epitaxial growth of GaN film and its applications in high-brightness LEDs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. High-energy Neutrino Flares from X-Ray Bright and Dark Tidal Disruption Events

    Energy Technology Data Exchange (ETDEWEB)

    Senno, Nicholas; Murase, Kohta; Mészáros, Peter [Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2017-03-20

    X-ray and γ-ray observations by the Swift satellite revealed that a fraction of tidal disruption events (TDEs) have relativistic jets. Jetted TDEs have been considered to be potential sources of very-high-energy cosmic-rays and neutrinos. In this work, using semi-analytical methods, we calculate neutrino spectra of X-ray bright TDEs with powerful jets and dark TDEs with possible choked jets, respectively. We estimate their neutrino fluxes and find that non-detection would give us an upper limit on the baryon loading of the jet luminosity contained in cosmic-rays ξ {sub cr} ≲ 20–50 for Sw J1644+57. We show that X-ray bright TDEs make a sub-dominant (≲5%–10%) contribution to IceCube’s diffuse neutrino flux, and study possible contributions of X-ray dark TDEs given that particles are accelerated in choked jets or disk winds. We discuss future prospects for multi-messenger searches of the brightest TDEs.

  6. Absolute brightness modeling for improved measurement of electron temperature from soft x-rays on MST

    Science.gov (United States)

    Reusch, L. M.; Franz, P.; Goetz, J. A.; den Hartog, D. J.; Nornberg, M. D.; van Meter, P.

    2017-10-01

    The two-color soft x-ray tomography (SXT) diagnostic on MST is now capable of Te measurement down to 500 eV. The previous lower limit was 1 keV, due to the presence of SXR emission lines from Al sputtered from the MST wall. The two-color technique uses two filters of different thickness to form a coarse spectrometer to estimate the slope of the continuum x-ray spectrum, which depends on Te. The 1.6 - 2.0 keV Al emission lines were previously filtered out by using thick Be filters (400 µm and 800 µm), thus restricting the range of the SXT diagnostic to Te >= 1 keV. Absolute brightness modeling explicitly includes several sources of radiation in the analysis model, enabling the use of thinner filters and measurement of much lower Te. Models based on the atomic database and analysis structure (ADAS) agree very well with our experimental SXR measurements. We used ADAS to assess the effect of bremsstrahlung, recombination, dielectronic recombination, and line emission on the inferred Te. This assessment informed the choice of the optimum filter pair to extend the Te range of the SXT diagnostic. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences program under Award Numbers DE-FC02-05ER54814 and DE-SC0015474.

  7. Design of high-brightness TEM00-mode solar-pumped laser for renewable material processing

    Science.gov (United States)

    Liang, D.; Almeida, J.

    2014-08-01

    The conversion of sunlight into laser light by direct solar pumping is of ever-increasing importance because broadband, temporally constant, sunlight is converted into laser light, which can be a source of narrowband, collimated, rapidly pulsed, radiation with the possibility of obtaining extremely high brightness and intensity. Nonlinear processes, such as harmonic generation, might be used to obtain broad wavelength coverage, including the ultraviolet wavelengths, where the solar flux is very weak. The direct excitation of large lasers by sunlight offers the prospect of a drastic reduction in the cost of coherent optical radiation for high average power materials processing. This renewable laser has a large potential for many applications such as high-temperature materials processing, renewable magnesium-hydrogen energy cycle and so on. We propose here a scalable TEM00 mode solar laser pumping scheme, which is composed of four firststage 1.13 m diameter Fresnel lenses with its respective folding mirrors mounted on a two-axis automatic solar tracker. Concentrated solar power at the four focal spots of these Fresnel lenses are focused individually along a common 3.5 mm diameter, 70 mm length Nd:YAG rod via four pairs of second-stage fused-silica spherical lenses and third-stage 2D-CPCs (Compound Parabolic Concentrator), sitting just above the laser rod which is also double-pass pumped by four V-shaped pumping cavities. Distilled water cools both the rod and the concentrators. 15.4 W TEM00 solar laser power is numerically calculated, corresponding to 6.7 times enhancement in laser beam brightness.

  8. Development of a high brightness ion source for IFMIF and preliminary test results

    International Nuclear Information System (INIS)

    Iga, Takashi; Okumura, Yoshikazu; Kashiwagi, Mieko

    2001-05-01

    Development of a high brightness ion source for the 40MeV/250mA deuteron beam accelerator, IFMIF, is in progress at JAERI. A prototype ion source using hot filament cathodes has been developed. This ion source consists of a multi-cusp plasma generator and a two-stage accelerator. Beam optics has been investigated at the energy of up to 60keV. Experimental results of the beam optics agreed well with the simulation by assuming that the equivalent ion mass is 2.38. Ion beam of 60keV/100mA H+, which corresponds to ion beam of 100keV/220mA D+, was obtained with optimum perveance (minimum divergence). This result indicates that the current requirement for the IFMIF ion source would be satisfied with this ion source. (author)

  9. Design of a Multi-Color Lamp Using High Brightness RGB LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Song, S.B.; Kang, S.H.; Yeo, I.S. [Chonnam National University, Kwangju (Korea)

    2003-02-01

    This paper proposes the design of a multi-color lamp using high brightness RGB LEDs for color variation. Appropriate number of RGB LEDs is so chosen according to the color mixing theory that the overall LEDs represent a color temperature of 6500K. Also, the chosen RGB LEDs are suitably arranged by using an optical design program. The lamp has an internal controller circuit, so it can be directly connected to the existing incandescent lamp socket. It's main body is comprised of two PCB layers. The upper layer contains 44 LEDs and the lower one has a simple microcontroller-based PWM control circuit. The lamp has functions of both ON/OFF control and PWM control, and enables color variation of over 100,000 colors and of more than 10 patterns. (author). 7 refs., 11 figs., 3 tabs.

  10. Experience with a high-brightness storage ring: the NSLS 750 MeV vuv ring

    International Nuclear Information System (INIS)

    Galayda, J.

    1984-01-01

    The NSLS vuv ring is the first implementation of the proposals of R. Chasman and G.K. Green for a synchrotron radiation source with enhanced brightness: its lattice is a series of achromatic bends with two zero-gradient dipoles each, giving small damped emittance; and these bends are connected by straight sections with zero dispersion to accommodate wigglers and undulators without degrading the radiation damping properties of the ring. The virtues of the Chasman-Green lattice, its small betatron and synchrotron emittances, may be understood with some generality; e.g. the electron γm 0 c 2 energy and the number of achromatic bends M sets a lower limit on the betatron emittance of e/sub x/ > 7.7 x 10 -13 γ 2 /M meter-radians. There is strong interest in extrapolation of this type of lattice to 6 GeV and to 32 achromatic bends. The subject of this report is the progress toward achieving performance in the vuv ring limited by the radiation damping parameters optimized in its design. 14 refs., 4 figs., 1 tab

  11. Enhanced brightness of organic light-emitting diodes based on Mg:Ag cathode using alkali metal chlorides as an electron injection layer

    International Nuclear Information System (INIS)

    Zou Ye; Deng Zhenbo; Xu Denghui; Lü Zhaoyue; Yin Yuehong; Du Hailiang; Chen Zheng; Wang Yongsheng

    2012-01-01

    Different thicknesses of cesium chloride (CsCl) and various alkali metal chlorides were inserted into organic light-emitting diodes (OLEDs) as electron injection layers (EILs). The basic structure of OLED is indium tin oxide (ITO)/N,N′-diphenyl-N,N′-bis(1-napthyl-phenyl)-1.1′-biphenyl-4.4′-diamine (NPB)/tris-(8-hydroxyquinoline) aluminum (Alq 3 )/Mg:Ag/Ag. The electroluminescent (EL) performance curves show that both the brightness and efficiency of the OLEDs can be obviously enhanced by using a thin alkali metal chloride layer as an EIL. The electron injection barrier height between the Alq 3 layer and Mg:Ag cathode is reduced by inserting a thin alkali metal chloride as an EIL, which results in enhanced electron injection and electron current. Therefore, a better balance of hole and electron currents at the emissive interface is achieved and consequently the brightness and efficiency of OLEDs are improved. - Highlights: ► Alkaline metal chlorides were used as electron injection layers in organic light-emitting diodes based on Mg:Ag cathode. ► Brightness and efficiency of OLEDs with alkaline metal chlorides as electron injection layers were all greatly enhanced. ► The Improved OLED performance was attributed to the possible interfacial chemical reaction. ► Electron-only devices are fabricated to demonstrate the electron injection enhancement.

  12. Mapping bright and dark modes in gold nanoparticle chains using electron energy loss spectroscopy.

    Science.gov (United States)

    Barrow, Steven J; Rossouw, David; Funston, Alison M; Botton, Gianluigi A; Mulvaney, Paul

    2014-07-09

    We present a scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) investigation of gold nanosphere chains with lengths varying from 1 to 5 particles. We show localized EELS signals from the chains and identify energy-loss peaks arising due to l = 1, 2, 3, 4, and 5 plasmon modes through the use of EELS mapping. We also show the evolution of the energy of these modes as the length of a given chain increases, and we find that a chain containing N particles can accommodate at least N experimentally observable modes, in addition to the transverse mode. As the chain length is increased by the addition of one more gold particle to the chain, the new N + 1 mode becomes the highest energy mode, while the existing modes lower their energy and eventually asymptote as they delocalize along the chain. We also show that modes become increasingly difficult to detect with the EELS technique as l approaches N. The data are compared to numerical simulations.

  13. Strain relief InGaN/GaN MQW micro-pillars for high brightness LEDs

    KAUST Repository

    Shen, Chao

    2013-01-01

    Micro-structured group-III-nitrides are considered as promising strain relief structures for high efficiency solid state lighting. In this work, the strain field in InGaN/GaN multi-quantum wells (MQWs) micro-pillars is investigated using micro-Raman spectroscopy and the design of micro-pillars were studied experimentally. We distinguished the strained and strain-relieved signatures of the GaN layer from the E2 phonon peak split from the Raman scattering signatures at 572 cm-1 and 568 cm-1, respectively. The extent of strain relief is examined considering the height and size of micro-pillars fabricated using focused ion beam (FIB) micro-machining technique. A significant strain relief can be achieved when one micro-machined through the entire epi-layers, 3 μm in our study. The dependence of strain relief on micro-pillar diameter (D) suggested that micro-pillar with D < 3 μm showed high degree of strain relief. Our results shed new insights into designing strain-relieved InGaN/GaN microstructures for high brightness light emitting diode arrays. © 2013 IEEE.

  14. A time-dependent search for high-energy neutrinos from bright GRBs with ANTARES

    Directory of Open Access Journals (Sweden)

    Celli Silvia

    2017-01-01

    Full Text Available Astrophysical point-like neutrino sources, like Gamma-Ray Bursts (GRBs, are one of the main targets for neutrino telescopes, since they are among the best candidates for Ultra-High-Energy Cosmic Ray (UHECR acceleration. From the interaction between the accelerated protons and the intense radiation fields of the source jet, charged mesons are produced, which then decay into neutrinos. The methods and the results of a search for high-energy neutrinos in spatial and temporal correlation with the detected gamma-ray emission are presented for four bright GRBs observed between 2008 and 2013: a time-dependent analysis, optimised for each flare of the selected bursts, is performed to predict detailed neutrino spectra. The internal shock scenario of the fireball model is investigated, relying on the neutrino spectra computed through the numerical code NeuCosmA. The analysis is optimized on a per burst basis, through the maximization of the signal discovery probability. Since no events in ANTARES data passed the optimised cuts, 90% C.L. upper limits are derived on the expected neutrino fluences.

  15. THE STATISTICS OF RADIO ASTRONOMICAL POLARIMETRY: BRIGHT SOURCES AND HIGH TIME RESOLUTION

    International Nuclear Information System (INIS)

    Van Straten, W.

    2009-01-01

    A four-dimensional statistical description of electromagnetic radiation is developed and applied to the analysis of radio pulsar polarization. The new formalism provides an elementary statistical explanation of the modal-broadening phenomenon in single-pulse observations. It is also used to argue that the degree of polarization of giant pulses has been poorly defined in past studies. Single- and giant-pulse polarimetry typically involves sources with large flux-densities and observations with high time-resolution, factors that necessitate consideration of source-intrinsic noise and small-number statistics. Self-noise is shown to fully explain the excess polarization dispersion previously noted in single-pulse observations of bright pulsars, obviating the need for additional randomly polarized radiation. Rather, these observations are more simply interpreted as an incoherent sum of covariant, orthogonal, partially polarized modes. Based on this premise, the four-dimensional covariance matrix of the Stokes parameters may be used to derive mode-separated pulse profiles without any assumptions about the intrinsic degrees of mode polarization. Finally, utilizing the small-number statistics of the Stokes parameters, it is established that the degree of polarization of an unresolved pulse is fundamentally undefined; therefore, previous claims of highly polarized giant pulses are unsubstantiated.

  16. High-efficient and brightness white organic light-emitting diodes operated at low bias voltage

    Science.gov (United States)

    Zhang, Lei; Yu, Junsheng; Yuan, Kai; Jian, Yadong

    2010-10-01

    White organic light-emitting diodes (OLEDs) used for display application and lighting need to possess high efficiency, high brightness, and low driving voltage. In this work, white OLEDs consisted of ambipolar 9,10-bis 2-naphthyl anthracene (ADN) as a host of blue light-emitting layer (EML) doped with tetrabutyleperlene (TBPe) and a thin codoped layer consisted of N, N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (NPB) as a host of yellow light-emitting layer doped with 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) were investigated. With appropriate tuning in the film thickness, position, and dopant concentration of the co-doped layer, a white OLED with a luminance yield of 10.02 cd/A with the CIE coordinates of (0.29, 0.33) has been achieved at a bias voltage of 9 V and a luminance level of over 10,000 cd/m2. By introducing the PIN structure with both HIL and bis(10- hydroxybenzo-quinolinato)-beryllium (BeBq2) ETL, the power efficiency of white OLED was improved.

  17. Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: Implications for tomography of thick biological sections

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, A.A.; Hohmann-Marriott, M.F.; Zhang, G. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 13 South Drive, Bethesda, MD 20892-5766 (United States); Leapman, R.D. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 13 South Drive, Bethesda, MD 20892-5766 (United States)], E-mail: leapmanr@mail.nih.gov

    2009-02-15

    A Monte Carlo electron-trajectory calculation has been implemented to assess the optimal detector configuration for scanning transmission electron microscopy (STEM) tomography of thick biological sections. By modeling specimens containing 2 and 3 at% osmium in a carbon matrix, it was found that for 1-{mu}m-thick samples the bright-field (BF) and annular dark-field (ADF) signals give similar contrast and signal-to-noise ratio provided the ADF inner angle and BF outer angle are chosen optimally. Spatial resolution in STEM imaging of thick sections is compromised by multiple elastic scattering which results in a spread of scattering angles and thus a spread in lateral distances of the electrons leaving the bottom surface. However, the simulations reveal that a large fraction of these multiply scattered electrons are excluded from the BF detector, which results in higher spatial resolution in BF than in high-angle ADF images for objects situated towards the bottom of the sample. The calculations imply that STEM electron tomography of thick sections should be performed using a BF rather than an ADF detector. This advantage was verified by recording simultaneous BF and high-angle ADF STEM tomographic tilt series from a stained 600-nm-thick section of C. elegans. It was found that loss of spatial resolution occurred markedly at the bottom surface of the specimen in the ADF STEM but significantly less in the BF STEM tomographic reconstruction. Our results indicate that it might be feasible to use BF STEM tomography to determine the 3D structure of whole eukaryotic microorganisms prepared by freeze-substitution, embedding, and sectioning.

  18. Experimental results in superconducting niobium resonators for high-brightness ion beam acceleration

    International Nuclear Information System (INIS)

    Delayen, J.R.; Bohn, C.L.; Roche, C.T.

    1991-01-01

    Two niobium resonant cavities for high-brightness ion beam acceleration have been constructed and tested. The first was based on a coaxial quarter-wave geometry and was optimized for phase velocity β O = O.15. This cavity, which resonates at 400 MHz in the fundamental mode, operated at an average (wall-to-wall) accelerating gradient of 12.9 MV/m under continuous-wave (cw) fields. At this gradient, a cavity Q of 1.4x10 8 was measured. The second was based on a coaxial half-wave geometry and was optimized for β O = 0.12. This cavity, which resonates at 355 MHz in the fundamental mode, operated at an average accelerating gradient of 18.0 MV/m under cw fields. This is the highest average accelerating gradient achieved to date in low-velocity structures designed for cw operation. At this gradient, a cavity Q of 1.2 x 10 8 was measured

  19. Bright electroluminescence from a chelate phosphine oxide Eu{sup III} complex with high thermal performance

    Energy Technology Data Exchange (ETDEWEB)

    Xu Hui [School of Chemistry and Materials, Heilongjiang University, 74 Xuefu Road, Nangang District, Harbin 150080, Heilongjiang Province (China); Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Yin Kun; Wang Lianhui [Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Huang Wei [Institute of Advanced Materials (IAM), Fudan University, 220 Handan Road, Shanghai 200433 (China)], E-mail: wei-huang@njupt.edu.cn

    2008-10-01

    The chelate phosphine oxide ligand 1,8-bis(diphenylphosphino)naphthalene oxide (NaPO) was used to prepare complex 1 tris(2-thenoyltrifluoroacetonate)(1,8-bis(diphenylphosphino)naphthalene oxide)europium(III). The rigid structure of NaPO makes 1 have more compact structure resulting in a temperature of glass transition as high as 147 deg. C, which is the highest in luminescent Eu{sup III} complexes, and a higher decomposition temperature of 349 deg. C. The improvement of carrier transfer ability of NaPO was proved by Gaussian simulation. The multi-layered electroluminescent device based on 1 had a low turn-on voltage of 6.0 V, the maximum brightness of 601 cd m{sup -2} at 21.5 V and 481.4 mA cm{sup -2}, and the excellent voltage-independent spectral stability. These properties demonstrated NaPO cannot only be favorable to form the rigid and compact complex structure, and increase the thermal and morphological stability of the complex, but also reduce the formation of the exciplex.

  20. Proceedings of the 2016 Workshop on the Physics and Applications of High Brightness Beams

    Science.gov (United States)

    Cianchi, Alessandro; Ferrario, Massimo; Musumeci, Pietro; Rosenzweig, James

    2017-09-01

    We are proud to present the proceedings of the latest in the series of International Committee on Future Accelerators (ICFA)-endorsed workshops on the Physics and Applications of High Brightness Beams, which has been held at the Hotel Nacional in Havana, Cuba between March 28 and April 1, 2016. In total, 135 participants coming from 14 different countries attended this historic conference. In recognition of its pioneering role in the significant blossoming of relations between Cuba and the larger scientific community, this workshop also received the endorsement of UNESCO. The workshop organization was headed by co-chairs Massimo Ferrario (INFN-LNF) and James Rosenzweig (UCLA), with the essential and energetic contributions of local organizing committee chair Fidel Antonio Castro Smirnov (InSTEC, Havana). The workshop scientific agenda was developed under the care of program committee co-chairs Pietro Musumeci (UCLA) and Luca Serafini (INFN-Milano). The publication of the proceedings we present here was led by Alessandro Cianchi (Tor Vergata). Tangible contributions to the workshop infrastructure were received from UCLA, INFN-LNF, InSTEC, EuroNNAC2, and the US National Science Foundation. The workshop web site, which contains detailed information on the scientific agenda of the meeting, is found at https://conferences.pa.ucla.edu/hbb/.

  1. TH-CD-207B-01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple-Pixel X-Ray Source Using Oxide Coated Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Kandlakunta, P; Pham, R; Zhang, T [Washington University School of Medicine, St. Louis, MO (United States)

    2016-06-15

    Purpose: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. Methods: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro-rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x-ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm{sup 2}. The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x-ray measurements estimated the focal spot size as 1.5 × 1.3 mm{sup 2}. Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x-ray beams with a fast switching speed.

  2. The LLNL/UCLA high gradient inverse free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Moody, J. T.; Musumeci, P.; Anderson, G.; Anderson, S.; Betts, S.; Fisher, S.; Gibson, D.; Tremaine, A.; Wu, S. [Department of Physics and Astronomy, UCLA, Los Angeles California, 90095 (United States); Lawrence Livermore National Laboratory (United States)

    2012-12-21

    We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of > 200 MeV/m. We present the final design of the accelerator as well as the results of start-to-end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

  3. Decal electronics for printed high performance cmos electronic systems

    KAUST Repository

    Hussain, Muhammad Mustafa; Sevilla, Galo Torres; Cordero, Marlon Diaz; Kutbee, Arwa T.

    2017-01-01

    High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications

  4. Search for high-energy neutrinos from bright GRBs with ANTARES

    NARCIS (Netherlands)

    Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M.C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, J.A.B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Felis, I.; Fusco, L.A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Grégoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A.J.; Hello, Y.; Hernández-Rey, J.J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C.W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J.A.; Mathieu, A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Pavalas, G.E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Roensch, K.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D.F.E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, T.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Vizzocca, A.; Wagner, S.; Wilms, J.; Zornoza, J.D.; Zúñiga, J.

    2017-01-01

    Gamma-ray bursts are thought to be sites of hadronic acceleration, thus neutrinos are expected from the decay of charged particles, produced in pγ interactions. The methods and results of a search for muon neutrinos in the data of the ANTARES neutrino telescope from four bright GRBs (GRB 080916C,

  5. High cortisol awakening response is associated with an impairment of the effect of bright light therapy

    DEFF Research Database (Denmark)

    Martiny, Klaus Per Juul; Lunde, Marianne Anita; Undén, M

    2009-01-01

    OBJECTIVE: We investigated the predictive validity of the cortisol awakening response (CAR) in patients with non-seasonal major depression. METHOD: Patients were treated with sertraline in combination with bright or dim light therapy for a 5-week period. Saliva cortisol levels were measured in 63...

  6. Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap

    Energy Technology Data Exchange (ETDEWEB)

    Maxson, Jared; Bazarov, Ivan; Dunham, Bruce; Dobbins, John; Liu, Xianghong; Smolenski, Karl [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States)

    2014-09-15

    A new high voltage photoemission gun has been constructed at Cornell University which features a segmented insulator and a movable anode, allowing the cathode-anode gap to be adjusted. In this work, we describe the gun's overall mechanical and high voltage design, the surface preparation of components, as well as the clean construction methods. We present high voltage conditioning data using a 50 mm cathode-anode gap, in which the conditioning voltage exceeds 500 kV, as well as at smaller gaps. Finally, we present simulated emittance results obtained from a genetic optimization scheme using voltage values based on the conditioning data. These results indicate that for charges up to 100 pC, a 30 mm gap at 400 kV has equal or smaller 100% emittance than a 50 mm gap at 450 kV, and also a smaller core emittance, when placed as the source for the Cornell energy recovery linac photoinjector with bunch length constrained to be <3 ps rms. For 100 pC up to 0.5 nC charges, the 50 mm gap has larger core emittance than the 30 mm gap, but conversely smaller 100% emittance.

  7. The Grumman/Brookhaven high-brightness, high-duty factor RF gun

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Birnbaum, I.A.; Cole, M.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Waren, G.D.

    1992-01-01

    Under a joint collaboration between Brookhaven National Laboratory and the Grumman Corporation, a high-duty (>1%) photocathode RF gun is under construction for use at the ATF facility at BNL. The gun will be capable of producing short ( 300 A (after compression) and a total bunch charge in excess of 3 nC. The gun consists of 3-1/2 cells constructed from GlidCop, an alumina dispersion strengthened copper alloy. Two individually phased waveguides are used to power the first two and final two cells. (Author) 10 refs., 8 figs., 2 tabs

  8. Recent developments in the application of rf superconductivity to high-brightness and high-gradient ion beam accelerators

    International Nuclear Information System (INIS)

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

    1991-01-01

    A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high- brightness ion beams. Since the last workshop, 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 2 ) surface areas. Theoretical studies of beam impingement and cumulative beam breakup have also yielded encouraging results. Consequently, a section of superconducting resonators and focusing elements has been designed for tests with high-current deuteron beams. In addition, considerable data pertaining to the rf properties of high-T c superconductors has been collected at rf-field amplitudes and frequencies of interest in connection with accelerator operation. This paper summarizes the recent progress and identifies current and future work in the areas of accelerator technology and superconducting materials which will build upon it

  9. High-efficiency, 154  W CW, diode-pumped Raman fiber laser with brightness enhancement.

    Science.gov (United States)

    Glick, Yaakov; Fromzel, Viktor; Zhang, Jun; Ter-Gabrielyan, Nikolay; Dubinskii, Mark

    2017-01-20

    We demonstrate a high-power, high-efficiency Raman fiber laser pumped directly by laser diode modules at 978 nm. 154 W of CW power were obtained at a wavelength of 1023 nm with an optical to optical efficiency of 65%. A commercial graded-index (GRIN) core fiber acts as the Raman fiber in a power oscillator configuration, which includes spectral selection to prevent generation of the second Stokes. In addition, brightness enhancement of the pump beam by a factor of 8.4 is attained due to the Raman gain distribution profile in the GRIN fiber. To the best of our knowledge this is the highest power and highest efficiency Raman fiber laser demonstrated in any configuration allowing brightness enhancement (i.e., in either cladding-pumped configuration or with GRIN fibers, excluding step-index core pumped), regardless of pumping scheme (i.e., either diode pumped or fiber laser pumped).

  10. The high brightness temperature of B0529+483 revealed by RadioAstron and implications for interstellar scattering

    Science.gov (United States)

    Pilipenko, S. V.; Kovalev, Y. Y.; Andrianov, A. S.; Bach, U.; Buttaccio, S.; Cassaro, P.; Cimò, G.; Edwards, P. G.; Gawroński, M. P.; Gurvits, L. I.; Hovatta, T.; Jauncey, D. L.; Johnson, M. D.; Kovalev, Yu A.; Kutkin, A. M.; Lisakov, M. M.; Melnikov, A. E.; Orlati, A.; Rudnitskiy, A. G.; Sokolovsky, K. V.; Stanghellini, C.; de Vicente, P.; Voitsik, P. A.; Wolak, P.; Zhekanis, G. V.

    2018-03-01

    The high brightness temperatures, Tb ≳ 1013 K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. Refractive scattering by the interstellar medium may affect such measurements. We quantify the scattering properties and the sub-mas scale source parameters for the quasar B0529+483. Using RadioAstron correlated flux density measurements at 1.7, 4.8, and 22 GHz on projected baselines up to 240 000 km we find two characteristic angular scales in the quasar core, about 100 and 10 μas. Some indications of scattering substructure are found. Very high brightness temperatures, Tb ≥ 1013 K, are estimated at 4.8 and 22 GHz even taking into account the refractive scattering. Our findings suggest a clear dominance of the particle energy density over the magnetic field energy density in the core of this quasar.

  11. High energy polarized electron beams

    International Nuclear Information System (INIS)

    Rossmanith, R.

    1987-01-01

    In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10 6 to 10 7 revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and the acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible

  12. High Brightness, Laser-Driven X-ray Source for Nanoscale Metrology and Femtosecond Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Siders, C W; Crane, J K; Semenov, V; Betts, S; Kozioziemski, B; Wharton, K; Wilks, S; Barbee, T; Stuart, B; Kim, D E; An, J; Barty, C

    2007-02-26

    This project developed and demonstrated a new, bright, ultrafast x-ray source based upon laser-driven K-alpha generation, which can produce an x-ray flux 10 to 100 times greater than current microfocus x-ray tubes. The short-pulse (sub-picosecond) duration of this x-ray source also makes it ideal for observing time-resolved dynamics of atomic motion in solids and thin films.

  13. High brightness fiber laser pump sources based on single emitters and multiple single emitters

    Science.gov (United States)

    Scheller, Torsten; Wagner, Lars; Wolf, Jürgen; Bonati, Guido; Dörfel, Falk; Gabler, Thomas

    2008-02-01

    Driven by the potential of the fiber laser market, the development of high brightness pump sources has been pushed during the last years. The main approaches to reach the targets of this market had been the direct coupling of single emitters (SE) on the one hand and the beam shaping of bars and stacks on the other hand, which often causes higher cost per watt. Meanwhile the power of single emitters with 100μm emitter size for direct coupling increased dramatically, which also pushed a new generation of wide stripe emitters or multi emitters (ME) of up to 1000μm emitter size respectively "minibars" with apertures of 3 to 5mm. The advantage of this emitter type compared to traditional bars is it's scalability to power levels of 40W to 60W combined with a small aperture which gives advantages when coupling into a fiber. We show concepts using this multiple single emitters for fiber coupled systems of 25W up to 40W out of a 100μm fiber NA 0.22 with a reasonable optical efficiency. Taking into account a further efficiency optimization and an increase in power of these devices in the near future, the EUR/W ratio pushed by the fiber laser manufacturer will further decrease. Results will be shown as well for higher power pump sources. Additional state of the art tapered fiber bundles for photonic crystal fibers are used to combine 7 (19) pump sources to output powers of 100W (370W) out of a 130μm (250μm) fiber NA 0.6 with nominal 20W per port. Improving those TFB's in the near future and utilizing 40W per pump leg, an output power of even 750W out of 250μm fiber NA 0.6 will be possible. Combined Counter- and Co-Propagated pumping of the fiber will then lead to the first 1kW fiber laser oscillator.

  14. Advancements in high-power high-brightness laser bars and single emitters for pumping and direct diode application

    Science.gov (United States)

    An, Haiyan; Jiang, Ching-Long J.; Xiong, Yihan; Zhang, Qiang; Inyang, Aloysius; Felder, Jason; Lewin, Alexander; Roff, Robert; Heinemann, Stefan; Schmidt, Berthold; Treusch, Georg

    2015-03-01

    We have continuously optimized high fill factor bar and packaging design to increase power and efficiency for thin disc laser system pump application. On the other hand, low fill factor bars packaged on the same direct copper bonded (DCB) cooling platform are used to build multi-kilowatt direct diode laser systems. We have also optimized the single emitter designs for fiber laser pump applications. In this paper, we will give an overview of our recent advances in high power high brightness laser bars and single emitters for pumping and direct diode application. We will present 300W bar development results for our next generation thin disk laser pump source. We will also show recent improvements on slow axis beam quality of low fill factor bar and its application on performance improvement of 4-5 kW TruDiode laser system with BPP of 30 mm*mrad from a 600 μm fiber. Performance and reliability results of single emitter for multiemitter fiber laser pump source will be presented as well.

  15. Generating a high brightness multi-kilowatt laser by dense spectral combination of VBG stabilized single emitter laser diodes

    Science.gov (United States)

    Fritsche, H.; Koch, Ralf; Krusche, B.; Ferrario, F.; Grohe, Andreas; Pflueger, S.; Gries, W.

    2014-05-01

    Generating high power laser radiation with diode lasers is commonly realized by geometrical stacking of diode bars, which results in high output power but poor beam parameter product (BPP). The accessible brightness in this approach is limited by the fill factor, both in slow and fast axis. By using a geometry that accesses the BPP of the individual diodes, generating a multi kilowatt diode laser with a BPP comparable to fiber lasers is possible. We will demonstrate such a modular approach for generating multi kilowatt lasers by combining single emitter diode lasers. Single emitter diodes have advantages over bars, mainly a simplified cooling, better reliability and a higher brightness per emitter. Additionally, because single emitters can be arranged in many different geometries, they allow building laser modules where the brightness of the single emitters is preserved. In order to maintain the high brightness of the single emitter we developed a modular laser design which uses single emitters in a staircase arrangement, then coupling two of those bases with polarization combination which is our basic module. Those modules generate up to 160 W with a BPP better than 7.5 mm*mrad. For further power scaling wavelength stabilization is crucial. The wavelength is stabilized with only one Volume Bragg Grating (VBG) in front of a base providing the very same feedback to all of the laser diodes. This results in a bandwidth of BPP better than 7.5 mm*mrad, which can easily coupled into a 100 μm fiber and 0.15 NA.

  16. Diffraction of high energy electrons

    International Nuclear Information System (INIS)

    Bourret, A.

    1981-10-01

    The diffraction of electrons by a crystal is examined to study its structure. As the electron-substance interaction is strong, it must be treated in a dynamic manner. Using the N waves theory and physical optics the base equations giving the wave at the outlet are deduced for a perfect crystal and their equivalence is shown. The more complex case of an imperfect crystal is then envisaged in these two approaches. In both cases, only the diffraction of high energy electrons ( > 50 KeV) are considered since in the diffraction of slow electrons back scattering cannot be ignored. Taking into account an increasingly greater number of beams, through fast calculations computer techniques, enables images to be simulated in very varied conditions. The general use of the Fast Fourier Transform has given a clear cut practical advantage to the multi-layer method [fr

  17. Application of a transverse phase-space measurement technique for high-brightness, H- beams to the GTA H- beam

    International Nuclear Information System (INIS)

    Johnson, K.F.; Garcia, R.C.; Rusthoi, D.P.; Sander, O.R.; Sandoval, D.P.; Shinas, M.A.; Smith, M.; Yuan, V.W.; Connolly, R.C.

    1995-01-01

    The Ground Test Accelerator (GTA) had the objective Of Producing a high-brightness, high-current H-beam. The major components were a 35 keV injector, a Radio Frequency Quadrupole (RFQ), an intertank matching section (IMS), and a drift tube linac (DTL), consisting of 10 modules. A technique for measuring the transverse phase-space of high-power density beams has been developed and tested. This diagnostic has been applied to the GTA H-beam. Experimental results are compared to the slit and collector technique for transverse phase-space measurements and to simulations

  18. Smart light random memory sprays Retinex: a fast Retinex implementation for high-quality brightness adjustment and color correction.

    Science.gov (United States)

    Banić, Nikola; Lončarić, Sven

    2015-11-01

    Removing the influence of illumination on image colors and adjusting the brightness across the scene are important image enhancement problems. This is achieved by applying adequate color constancy and brightness adjustment methods. One of the earliest models to deal with both of these problems was the Retinex theory. Some of the Retinex implementations tend to give high-quality results by performing local operations, but they are computationally relatively slow. One of the recent Retinex implementations is light random sprays Retinex (LRSR). In this paper, a new method is proposed for brightness adjustment and color correction that overcomes the main disadvantages of LRSR. There are three main contributions of this paper. First, a concept of memory sprays is proposed to reduce the number of LRSR's per-pixel operations to a constant regardless of the parameter values, thereby enabling a fast Retinex-based local image enhancement. Second, an effective remapping of image intensities is proposed that results in significantly higher quality. Third, the problem of LRSR's halo effect is significantly reduced by using an alternative illumination processing method. The proposed method enables a fast Retinex-based image enhancement by processing Retinex paths in a constant number of steps regardless of the path size. Due to the halo effect removal and remapping of the resulting intensities, the method outperforms many of the well-known image enhancement methods in terms of resulting image quality. The results are presented and discussed. It is shown that the proposed method outperforms most of the tested methods in terms of image brightness adjustment, color correction, and computational speed.

  19. 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

  20. Building block diode laser concept for high brightness laser output in the kW range and its applications

    Science.gov (United States)

    Ferrario, Fabio; Fritsche, Haro; Grohe, Andreas; Hagen, Thomas; Kern, Holger; Koch, Ralf; Kruschke, Bastian; Reich, Axel; Sanftleben, Dennis; Steger, Ronny; Wallendorf, Till; Gries, Wolfgang

    2016-03-01

    The modular concept of DirectPhotonics laser systems is a big advantage regarding its manufacturability, serviceability as well as reproducibility. By sticking to identical base components an economic production allows to serve as many applications as possible while keeping the product variations minimal. The modular laser design is based on single emitters and various combining technics. In a first step we accept a reduction of the very high brightness of the single emitters by vertical stacking several diodes in fast axis. This can be theoretically done until the combined fast axis beam quality is on a comparable level as the individual diodes slow axis beam quality without loosing overall beam performance after fiber coupling. Those stacked individual emitters can be wavelength stabilized by an external resonator, providing the very same feedback to each of those laser diodes which leads to an output power of about 100 W with BPP of BPP. The 500 W building blocks are consequently designed in a way that they feature a high flexibility with regard to their emitting wavelength bandwidth. Therefore, new wavelengths can be implemented by only exchanging parts and without any additional change of the production process. This design principal theoretically offers the option to adapt the wavelength of those blocks to any applications, from UV, visible into the far IR as long as there are any diodes commercially available. This opens numerous additional applications like laser pumping, scientific applications, materials processing such as cutting and welding of copper aluminum or steel and also medical application. Typical operating at wavelengths in the 9XX nm range, these systems are designed for and mainly used in cutting and welding applications, but adapted wavelength ranges such as 793 nm and 1530 nm are also offered. Around 15XX nm the diodes are already successfully used for resonant pumping of Erbium lasers [1]. Furthermore, the fully integrated electronic

  1. High Power Electron Accelerator Prototype

    CERN Document Server

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

    2005-01-01

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

  2. Label-free detection of cellular drug responses by high-throughput bright-field imaging and machine learning.

    Science.gov (United States)

    Kobayashi, Hirofumi; Lei, Cheng; Wu, Yi; Mao, Ailin; Jiang, Yiyue; Guo, Baoshan; Ozeki, Yasuyuki; Goda, Keisuke

    2017-09-29

    In the last decade, high-content screening based on multivariate single-cell imaging has been proven effective in drug discovery to evaluate drug-induced phenotypic variations. Unfortunately, this method inherently requires fluorescent labeling which has several drawbacks. Here we present a label-free method for evaluating cellular drug responses only by high-throughput bright-field imaging with the aid of machine learning algorithms. Specifically, we performed high-throughput bright-field imaging of numerous drug-treated and -untreated cells (N = ~240,000) by optofluidic time-stretch microscopy with high throughput up to 10,000 cells/s and applied machine learning to the cell images to identify their morphological variations which are too subtle for human eyes to detect. Consequently, we achieved a high accuracy of 92% in distinguishing drug-treated and -untreated cells without the need for labeling. Furthermore, we also demonstrated that dose-dependent, drug-induced morphological change from different experiments can be inferred from the classification accuracy of a single classification model. Our work lays the groundwork for label-free drug screening in pharmaceutical science and industry.

  3. Advanced chip designs and novel cooling techniques for brightness scaling of industrial, high power diode laser bars

    Science.gov (United States)

    Heinemann, S.; McDougall, S. D.; Ryu, G.; Zhao, L.; Liu, X.; Holy, C.; Jiang, C.-L.; Modak, P.; Xiong, Y.; Vethake, T.; Strohmaier, S. G.; Schmidt, B.; Zimer, H.

    2018-02-01

    The advance of high power semiconductor diode laser technology is driven by the rapidly growing industrial laser market, with such high power solid state laser systems requiring ever more reliable diode sources with higher brightness and efficiency at lower cost. In this paper we report simulation and experimental data demonstrating most recent progress in high brightness semiconductor laser bars for industrial applications. The advancements are in three principle areas: vertical laser chip epitaxy design, lateral laser chip current injection control, and chip cooling technology. With such improvements, we demonstrate disk laser pump laser bars with output power over 250W with 60% efficiency at the operating current. Ion implantation was investigated for improved current confinement. Initial lifetime tests show excellent reliability. For direct diode applications 96% polarization are additional requirements. Double sided cooling deploying hard solder and optimized laser design enable single emitter performance also for high fill factor bars and allow further power scaling to more than 350W with 65% peak efficiency with less than 8 degrees slow axis divergence and high polarization.

  4. Ultra-high brightness wavelength-stabilized kW-class fiber coupled diode laser

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Glenn, John D.

    2011-03-01

    TeraDiode has produced a fiber-coupled direct diode laser with a power level of 1,040 W from a 200 μm core diameter, 0.18 numerical aperture (NA) output fiber at a single center wavelength. This was achieved with a novel beam combining and shaping technique using COTS diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 18 mm-mrad and is the lowest BPP kW-class direct diode laser yet reported. The laser has been used to demonstrate laser cutting and welding of steel sheet metal up to 6.65 mm thick. Further advances of these ultra-bright lasers are also projected.

  5. THROUGH THE LOOKING GLASS: BRIGHT, HIGHLY MAGNIFIED GALAXY CANDIDATES AT z {approx} 7 BEHIND A1703

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, L. D.; Coe, D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bouwens, R. J.; Smit, R. [Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden (Netherlands); Zitrin, A. [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Ford, H. C.; Zheng, W. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Illingworth, G. D. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Benitez, N. [Instituto de Astrofisica de Andalucia (CSIC), C/Camino Bajo de Huetor 24, Granada 18008 (Spain); Broadhurst, T. J. [Department of Theoretical Physics, University of Basque Country UPV/EHU, Leioa (Spain)

    2012-03-01

    We report the discovery of seven strongly lensed Lyman-break galaxy (LBG) candidates at z {approx} 7 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging of A1703. The brightest candidate, called A1703-zD1, has an observed (lensed) magnitude of 24.0 AB (26{sigma}) in the WFC3/IR F160W band, making it 0.2 mag brighter than the z{sub 850}-dropout candidate recently reported behind the Bullet Cluster and 0.7 mag brighter than the previously brightest known z {approx} 7.6 galaxy, A1689-zD1. With a cluster magnification of {approx}9, this source has an intrinsic magnitude of H{sub 160} = 26.4 AB, a strong z{sub 850} - J{sub 125} break of 1.7 mag, and a photometric redshift of z {approx} 6.7. Additionally, we find six other bright LBG candidates with H{sub 160}-band magnitudes of 24.9-26.4, photometric redshifts z {approx} 6.4 - 8.8, and magnifications {mu} {approx} 3-40. Stellar population fits to the Advanced Camera for Surveys, WFC3/IR, and Spitzer/Infrared Array Camera data for A1703-zD1 and A1703-zD4 yield stellar masses (0.7 - 3.0) Multiplication-Sign 10{sup 9} M{sub Sun }, stellar ages 5-180 Myr, and star formation rates {approx}7.8 M{sub Sun} yr{sup -1}, and low reddening with A{sub V} {<=} 0.7. The source-plane reconstruction of the exceptionally bright candidate A1703-zD1 exhibits an extended structure, spanning {approx}4 kpc in the z {approx} 6.7 source plane, and shows three resolved star-forming knots of radius r {approx} 0.4 kpc.

  6. NOAA Climate Data Record (CDR) of Intersatellite Calibrated Clear-Sky High Resolution Infrared Radiation Sounder (HIRS) Channel 12 Brightness Temperature Version 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The High-Resolution Infrared Radiation Sounder (HIRS) of intersatellite calibrated channel 12 brightness temperature (TB) product is a gridded global monthly time...

  7. 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.

  8. High Intensity Polarized Electron Sources

    International Nuclear Information System (INIS)

    Poelker, Benard; Adderley, Philip; Brittian, Joshua; Clark, J.; Grames, Joseph; Hansknecht, John; McCarter, James; Stutzman, Marcy; Suleiman, Riad; Surles-law, Kenneth

    2008-01-01

    During the 1990s, at numerous facilities world wide, extensive RandD devoted to constructing reliable GaAs photoguns helped ensure successful accelerator-based nuclear and high-energy physics programs using spin polarized electron beams. Today, polarized electron source technology is considered mature, with most GaAs photoguns meeting accelerator and experiment beam specifications in a relatively trouble-free manner. Proposals for new collider facilities however, require electron beams with parameters beyond today's state-of-the-art and serve to renew interest in conducting polarized electron source RandD. And at CEBAF/Jefferson Lab, there is an immediate pressing need to prepare for new experiments that require considerably more beam current than before. One experiment in particular?Q-weak, a parity violation experiment that will look for physics beyond the Standard Model?requires 180 uA average current at polarization >80% for a duration of one year, with run-averaged helicity correlate

  9. Galaxy Size Evolution at High Redshift and Surface Brightness Selection Effects: Constraints from the Hubble Ultra Deep Field

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Blakeslee, J. P.; Broadhurst, T. J.; Franx, M.

    2004-08-01

    We use the exceptional depth of the Ultra Deep Field (UDF) and UDF-parallel Advanced Camera for Surveys fields to study the sizes of high-redshift (z~2-6) galaxies and address long-standing questions about possible biases in the cosmic star formation rate due to surface brightness dimming. Contrasting B-, V-, and i-dropout samples culled from the deeper data with those obtained from the shallower Great Observatories Origins Deep Survey fields, we demonstrate that the shallower data are essentially complete at bright magnitudes to z~0.4", >~3 kpc) low surface brightness galaxies are rare. A simple comparison of the half-light radii of the Hubble Deep Field-North + Hubble Deep Field-South U-dropouts with B-, V-, and i-dropouts from the UDF shows that the sizes follow a (1+z)-1.05+/-0.21 scaling toward high redshift. A more rigorous measurement compares different scalings of our U-dropout sample with the mean profiles for a set of intermediate-magnitude (26.0dropouts from the UDF. The best fit is found with a (1+z)-0.94+0.19-0.25 size scaling (for fixed luminosity). This result is then verified by repeating this experiment with different size measures, low-redshift samples, and magnitude ranges. Very similar scalings are found for all comparisons. A robust measurement of size evolution is thereby demonstrated for galaxies from z~6 to 2.5 using data from the UDF. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  10. The Bright and Dark Sides of High-redshift Starburst Galaxies from Herschel and Subaru Observations

    Energy Technology Data Exchange (ETDEWEB)

    Puglisi, A.; Rodighiero, G.; Rodríguez-Muñoz, L.; Mancini, C.; Franceschini, A. [Dipartimento di Fisica e Astronomia, Università di Padova, vicolo dell’Osservatorio 2, I-35122 Padova (Italy); Daddi, E.; Valentino, F.; Calabrò, A.; Jin, S. [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Renzini, A. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio, 5, I-35122 Padova (Italy); Silverman, J. D. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for for Advanced Study, The University of Tokyo, Kashiwanoha, Kashiwa 277-8583 (Japan); Kashino, D. [Institute for Astronomy, Department of Physics, ETH Zürich, Wolfgang-Pauli-strasse 27, CH-8093 Zürich (Switzerland); Mainieri, V.; Man, A. [ESO, Karl-Schwarschild-Straße 2, D-85748 Garching bei München (Germany); Darvish, B. [Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Pasadena, CA 91125 (United States); Maier, C. [University of Vienna, Department of Astrophysics, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria); Kartaltepe, J. S. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Sanders, D. B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2017-04-01

    We present rest-frame optical spectra from the FMOS-COSMOS survey of 12 z ∼ 1.6 Herschel starburst galaxies, with star formation rate (SFR) elevated by ×8, on average, above the star-forming main sequence (MS). Comparing the H α to IR luminosity ratio and the Balmer decrement, we find that the optically thin regions of the sources contain on average only ∼10% of the total SFR, whereas ∼90% come from an extremely obscured component that is revealed only by far-IR observations and is optically thick even in H α . We measure the [N ii]{sub 6583}/H α ratio, suggesting that the less obscured regions have a metal content similar to that of the MS population at the same stellar masses and redshifts. However, our objects appear to be metal-rich outliers from the metallicity–SFR anticorrelation observed at fixed stellar mass for the MS population. The [S ii]{sub 6732}/[S ii]{sub 6717} ratio from the average spectrum indicates an electron density n {sub e} ∼ 1100 cm{sup −3} , larger than what was estimated for MS galaxies but only at the 1.5 σ level. Our results provide supporting evidence that high- z MS outliers are analogous of local ULIRGs and are consistent with a major-merger origin for the starburst event.

  11. Sub-nanometer emittance monitor for high brightness synchrotron radiation source

    International Nuclear Information System (INIS)

    Nakajima, K.

    1991-01-01

    Method of measuring a very small beam emittance in electron storage rings is presented. The monitor can sense an intrinsic emittance of beam particles by detecting the angular distribution of Compton scatterings of laser photons on beam electrons. It is possible to achieve measurement resolution smaller than 10 -9 m-rad without difficulty. (author)

  12. Decal electronics for printed high performance cmos electronic systems

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-11-23

    High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications. While there exist bulk material reduction methods to flex them, such thinned CMOS electronics are fragile and vulnerable to handling for high throughput manufacturing. Here, we show a fusion of a CMOS technology compatible fabrication process for flexible CMOS electronics, with inkjet and conductive cellulose based interconnects, followed by additive manufacturing (i.e. 3D printing based packaging) and finally roll-to-roll printing of packaged decal electronics (thin film transistors based circuit components and sensors) focusing on printed high performance flexible electronic systems. This work provides the most pragmatic route for packaged flexible electronic systems for wide ranging applications.

  13. Characterization of electron beams generated in a high-voltage pulse-line-driven pseudospark discharge

    International Nuclear Information System (INIS)

    Ramaswamy, K.; Destler, W.W.; Segalov, Z.; Rodgers, J.

    1994-01-01

    Emittance and energy measurements have been performed on a high-brightness electron beam (>10 10 A/m 2 rad 2 ) with diameter in the range 1--3 mm and energy in the range 150--170 keV. This electron beam is generated by the mating of a hollow-cathode discharge device operating in the pseudospark regime to the output of a high-power pulse line accelerator. The measured effective emittance lies in the range between 30 and 90 mm mrad and increases with axial distance. Electron energy measurements indicate that the high-energy electrons are generated during the first 20--30 ns of the discharge. Both the emittance and energy experiments were performed at two different ambient argon gas pressures (92 and 152 mtorr). Beam expansion as a function of axial position has also been studied and a lower bound on the beam brightness has been obtained

  14. Through the Looking Glass: Bright, Highly Magnified Galaxy Candidates at z ~ 7 behind A1703

    Science.gov (United States)

    Bradley, L. D.; Bouwens, R. J.; Zitrin, A.; Smit, R.; Coe, D.; Ford, H. C.; Zheng, W.; Illingworth, G. D.; Benítez, N.; Broadhurst, T. J.

    2012-03-01

    We report the discovery of seven strongly lensed Lyman-break galaxy (LBG) candidates at z ~ 7 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging of A1703. The brightest candidate, called A1703-zD1, has an observed (lensed) magnitude of 24.0 AB (26σ) in the WFC3/IR F160W band, making it 0.2 mag brighter than the z 850-dropout candidate recently reported behind the Bullet Cluster and 0.7 mag brighter than the previously brightest known z ~ 7.6 galaxy, A1689-zD1. With a cluster magnification of ~9, this source has an intrinsic magnitude of H 160 = 26.4 AB, a strong z 850 - J 125 break of 1.7 mag, and a photometric redshift of z ~ 6.7. Additionally, we find six other bright LBG candidates with H 160-band magnitudes of 24.9-26.4, photometric redshifts z ~ 6.4 - 8.8, and magnifications μ ~ 3-40. Stellar population fits to the Advanced Camera for Surveys, WFC3/IR, and Spitzer/Infrared Array Camera data for A1703-zD1 and A1703-zD4 yield stellar masses (0.7 - 3.0) × 109 M ⊙, stellar ages 5-180 Myr, and star formation rates ~7.8 M ⊙ yr-1, and low reddening with AV Universities for Research in Astronomy under NASA contract NAS5-26555. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

  15. The Extremely Luminous Quasar Survey (ELQS) in SDSS and the high-z bright-end Quasar Luminosity Function

    Science.gov (United States)

    Schindler, Jan-Torge; Fan, Xiaohui; McGreer, Ian

    2018-01-01

    Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early Universe and their connection to massive galaxy formation. Unfortunately, extremely luminous quasars at high redshift are very rare objects. Only wide area surveys have a chance to constrain their population. The Sloan Digital Sky Survey (SDSS) nd the Baryon Oscillation Spectroscopic Survey (BOSS) have so far provided the most widely adopted measurements of the type I quasar luminosity function (QLF) at z>3. However, a careful re-examination of the SDSS quasar sample revealed that the SDSS quasar selection is in fact missing a significant fraction of $z~3$ quasars at the brightest end.We have identified the purely optical color selection of SDSS, where quasars at these redshifts are strongly contaminated by late-type dwarfs, and the spectroscopic incompleteness of the SDSS footprint as the main reasons. Therefore we have designed the Extremely Luminous Quasar Survey (ELQS), based on a novel near-infrared JKW2 color cut using WISE AllWISE and 2MASS all-sky photometry, to yield high completeness for very bright (i < 18.0) quasars in the redshift range of 2.8<= z<=5.0. It effectively uses Random Forest machine-learning algorithms on SDSS and WISE photometry for quasar-star classification and photometric redshift estimation.The ELQS is spectroscopically following up ~230 new quasar candidates in an area of ~12000 deg2 in the SDSS footprint, to obtain a well-defined and complete quasar sample for an accurate measurement of the bright-end quasar luminosity function (QLF) at 2.8<= z<=5.0. So far the ELQS has identified 75 bright new quasars in this redshift range and observations of the fall sky will continue until the end of the year. At the AAS winter meeting we will present the full spectroscopic results of the survey, including a re-estimation and extension of the high-z QLF toward higher luminosities.

  16. High-resolution SMA imaging of bright submillimetre sources from the SCUBA-2 Cosmology Legacy Survey

    Science.gov (United States)

    Hill, Ryley; Chapman, Scott C.; Scott, Douglas; Petitpas, Glen; Smail, Ian; Chapin, Edward L.; Gurwell, Mark A.; Perry, Ryan; Blain, Andrew W.; Bremer, Malcolm N.; Chen, Chian-Chou; Dunlop, James S.; Farrah, Duncan; Fazio, Giovanni G.; Geach, James E.; Howson, Paul; Ivison, R. J.; Lacaille, Kevin; Michałowski, Michał J.; Simpson, James M.; Swinbank, A. M.; van der Werf, Paul P.; Wilner, David J.

    2018-06-01

    We have used the Submillimeter Array (SMA) at 860 μm to observe the brightest sources in the Submillimeter Common User Bolometer Array-2 (SCUBA-2) Cosmology Legacy Survey (S2CLS). The goal of this survey is to exploit the large field of the S2CLS along with the resolution and sensitivity of the SMA to construct a large sample of these rare sources and to study their statistical properties. We have targeted 70 of the brightest single-dish SCUBA-2 850 μm sources down to S850 ≈ 8 mJy, achieving an average synthesized beam of 2.4 arcsec and an average rms of σ860 = 1.5 mJy beam-1 in our primary beam-corrected maps. We searched our SMA maps for 4σ peaks, corresponding to S860 ≳ 6 mJy sources, and detected 62, galaxies, including three pairs. We include in our study 35 archival observations, bringing our sample size to 105 bright single-dish submillimetre sources with interferometric follow-up. We compute the cumulative and differential number counts, finding them to overlap with previous single-dish survey number counts within the uncertainties, although our cumulative number count is systematically lower than the parent S2CLS cumulative number count by 14 ± 6 per cent between 11 and 15 mJy. We estimate the probability that a ≳10 mJy single-dish submillimetre source resolves into two or more galaxies with similar flux densities to be less than 15 per cent. Assuming the remaining 85 per cent of the targets are ultraluminous starburst galaxies between z = 2 and 3, we find a likely volume density of ≳400 M⊙ yr-1 sources to be {˜ } 3^{+0.7}_{-0.6} {× } 10^{-7} Mpc-3. We show that the descendants of these galaxies could be ≳4 × 1011 M⊙ local quiescent galaxies, and that about 10 per cent of their total stellar mass would have formed during these short bursts of star formation.

  17. 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.

  18. 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

  19. Ultra High Brightness/Low Cost Fiber Coupled Packaging, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — High peak power, high efficiency, high reliability lightweight, low cost QCW laser diode pump modules with up to 1000W of QCW output become possible with nLight's...

  20. Basic numerical study on gap influence of residual stress and distortion during high-brightness laser butt welding

    International Nuclear Information System (INIS)

    Serizawa, Hisashi; Mori, Daiki; Murakawa, Hidekazu

    2013-01-01

    High-brightness laser such as fiber laser or disk laser is expected to minimize the total heat input energy in welding due to its high beam quality, and the welding residual stress and distortion also seem to be reduced as a result. However, the diameter of high-brightness laser beam is less than 0.6 mm and it is difficult to set the beam position to contact face between two parts because in general there would be a gap due to quality of parts. In this study, in order to reveal the effect of gap on the residual stress and the welding distortion during fiber laser welding, the butt welding of two plates were examined through the thermal elastic-plastic analysis with a new gap element. From the result of thermal analyses, it was found that the homogeneous ellipsoid body could be applicable to model the shape of heat source for the fiber laser and the gap width would not influence the penetration shape when the gap width was changed from 0.1 to 0.25 mm. In addition, the elastic-plastic analyses indicated that the transverse shrinkage slightly increased with increasing the gap width, while this shrinkage without gap was much smaller than that with gap. Also, it was revealed that the welding speed largely affects both the welding residual stress and distortion. Moreover, it was found that the residual stress was almost independent of the jig position, while the position of fixtures slightly affected the transverse shrinkage. (author)

  1. High-energy emission from bright gamma-ray bursts using Fermi

    Energy Technology Data Exchange (ETDEWEB)

    Bissaldi, Elisabetta

    2010-05-25

    mainly based on the brightest bursts detected by GBM inside the LAT field-of-view. The determination of a consistent sample for upper-limit calculations can be established by selecting those bursts which have a strong signal in the GBM BGO detectors. The structure of this thesis can be summarized as follows: The first chapter introduces the basic concepts and scientific background of GRB physics. Afterwards, instrumental details about the Fermi instruments LAT and GBM, as well as LAT performance and capabilities for GRB science are presented in chapter 2. Chapter 3 focuses on the detector-level calibration of the GBM instrument, and in particular on the analysis methods and results, which crucially support the development of a consistent GBM instrument response. The main GBM scientific results collected during the first year of operation are then presented in chapter 4. Particular emphasis is given to the description of joint GBM-LAT and GBM-Swift observations and analysis results. The last chapter presents the selection methodology and detailed spectral analysis of a sample of well-defined BGO-bright bursts detected by GBM during its first year. Using these results, correlations among spectral parameters are finally discussed. (orig.)

  2. High-energy emission from bright gamma-ray bursts using Fermi

    International Nuclear Information System (INIS)

    Bissaldi, Elisabetta

    2010-01-01

    on the brightest bursts detected by GBM inside the LAT field-of-view. The determination of a consistent sample for upper-limit calculations can be established by selecting those bursts which have a strong signal in the GBM BGO detectors. The structure of this thesis can be summarized as follows: The first chapter introduces the basic concepts and scientific background of GRB physics. Afterwards, instrumental details about the Fermi instruments LAT and GBM, as well as LAT performance and capabilities for GRB science are presented in chapter 2. Chapter 3 focuses on the detector-level calibration of the GBM instrument, and in particular on the analysis methods and results, which crucially support the development of a consistent GBM instrument response. The main GBM scientific results collected during the first year of operation are then presented in chapter 4. Particular emphasis is given to the description of joint GBM-LAT and GBM-Swift observations and analysis results. The last chapter presents the selection methodology and detailed spectral analysis of a sample of well-defined BGO-bright bursts detected by GBM during its first year. Using these results, correlations among spectral parameters are finally discussed. (orig.)

  3. On the Feasibility of Very-Low-Density Pure Metal Foams as Bright High-Energy X-ray Sources

    Science.gov (United States)

    Colvin, Jeffrey; Felter, Thomas

    2003-10-01

    We have used the Busquet approximation (M. Busquet, Phys. Fluids B 5(11), 4191 (1993)) to explore calculationally what the possible x-ray conversion efficiencies into the K-band would be from irradiating very-low-density pure metal foams with tens of kilojoules of 1/3-micron laser light. We will discuss the advantages of pure metal foams as bright high-energy x-ray sources, and some results of this calculational study. We will also present our ideas for how to fabricate pure metal foams with densities of a few milligrams per cubic centimeter. This work was performed under the auspices of the US Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  4. Nanopatterned yttrium aluminum garnet phosphor incorporated film for high-brightness GaN-based white light emitting diodes

    International Nuclear Information System (INIS)

    Cho, Joong-yeon; Park, Sang-Jun; Ahn, Jinho; Lee, Heon

    2014-01-01

    In this study, we fabricated high-brightness white light emitting diodes (LEDs) by developing a nanopatterned yttrium aluminum garnet (YAG) phosphor-incorporated film. White light can be obtained by mixing blue light from a GaN-based LED and yellow light of the YAG phosphor-incorporated film. If white light sources can be fabricated by exciting proper yellow phosphor using blue light, then these sources can be used instead of the conventional fluorescent lamps with a UV source, for backlighting of displays. In this work, a moth-eye structure was formed on the YAG phosphor-incorporated film by direct spin-on glass (SOG) printing. The moth-eye structures have been investigated to improve light transmittance in various optoelectronic devices, including photovoltaic solar cells, light emitting diodes, and displays, because of their anti-reflection property. Direct SOG printing, which is a simple, easy, and relatively inexpensive process, can be used to fabricate nanoscale structures. After direct SOG printing, the moth-eye structure with a diameter of 220 nm was formed uniformly on the YAG phosphor-incorporated film. As a result of moth-eye patterning on the YAG phosphor-incorporated film, the light output power of a white LED with a patterned YAG phosphor-incorporated film increased to up to 13% higher than that of a white LED with a non-patterned film. - Highlights: • GaN-based high-brightness white LED was prepared using patterned YAG phosphor-incorporated films. • Direct hydrogen silsesquioxane printing was used to form moth-eye patterns on the YAG films. • The electroluminescence intensity of the white LED was enhanced by up to 14.9%

  5. Nanopatterned yttrium aluminum garnet phosphor incorporated film for high-brightness GaN-based white light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Joong-yeon; Park, Sang-Jun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Ahn, Jinho, E-mail: jhahn@hanyang.ac.kr [Department of Material Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Heon, E-mail: heonlee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2014-11-03

    In this study, we fabricated high-brightness white light emitting diodes (LEDs) by developing a nanopatterned yttrium aluminum garnet (YAG) phosphor-incorporated film. White light can be obtained by mixing blue light from a GaN-based LED and yellow light of the YAG phosphor-incorporated film. If white light sources can be fabricated by exciting proper yellow phosphor using blue light, then these sources can be used instead of the conventional fluorescent lamps with a UV source, for backlighting of displays. In this work, a moth-eye structure was formed on the YAG phosphor-incorporated film by direct spin-on glass (SOG) printing. The moth-eye structures have been investigated to improve light transmittance in various optoelectronic devices, including photovoltaic solar cells, light emitting diodes, and displays, because of their anti-reflection property. Direct SOG printing, which is a simple, easy, and relatively inexpensive process, can be used to fabricate nanoscale structures. After direct SOG printing, the moth-eye structure with a diameter of 220 nm was formed uniformly on the YAG phosphor-incorporated film. As a result of moth-eye patterning on the YAG phosphor-incorporated film, the light output power of a white LED with a patterned YAG phosphor-incorporated film increased to up to 13% higher than that of a white LED with a non-patterned film. - Highlights: • GaN-based high-brightness white LED was prepared using patterned YAG phosphor-incorporated films. • Direct hydrogen silsesquioxane printing was used to form moth-eye patterns on the YAG films. • The electroluminescence intensity of the white LED was enhanced by up to 14.9%.

  6. Sensitivity of Support Vector Machine Predictions of Passive Microwave Brightness Temperature Over Snow-covered Terrain in High Mountain Asia

    Science.gov (United States)

    Ahmad, J. A.; Forman, B. A.

    2017-12-01

    High Mountain Asia (HMA) serves as a water supply source for over 1.3 billion people, primarily in south-east Asia. Most of this water originates as snow (or ice) that melts during the summer months and contributes to the run-off downstream. In spite of its critical role, there is still considerable uncertainty regarding the total amount of snow in HMA and its spatial and temporal variation. In this study, the NASA Land Information Systems (LIS) is used to model the hydrologic cycle over the Indus basin. In addition, the ability of support vector machines (SVM), a machine learning technique, to predict passive microwave brightness temperatures at a specific frequency and polarization as a function of LIS-derived land surface model output is explored in a sensitivity analysis. Multi-frequency, multi-polarization passive microwave brightness temperatures as measured by the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) over the Indus basin are used as training targets during the SVM training process. Normalized sensitivity coefficients (NSC) are then computed to assess the sensitivity of a well-trained SVM to each LIS-derived state variable. Preliminary results conform with the known first-order physics. For example, input states directly linked to physical temperature like snow temperature, air temperature, and vegetation temperature have positive NSC's whereas input states that increase volume scattering such as snow water equivalent or snow density yield negative NSC's. Air temperature exhibits the largest sensitivity coefficients due to its inherent, high-frequency variability. Adherence of this machine learning algorithm to the first-order physics bodes well for its potential use in LIS as the observation operator within a radiance data assimilation system aimed at improving regional- and continental-scale snow estimates.

  7. Characterization techniques for the high-brightness particle beams of the Advanced Photon Source (APS)

    International Nuclear Information System (INIS)

    Lumpkin, A.H.

    1993-01-01

    The Advanced Photon Source (APS) will be a third-generation synchrotron radiation (SR) user facility in the hard x-ray regime (10--100 keV). The design objectives for the 7-GeV storage ring include a positron beam natural emittance of 8 x 10 -9 m-rad at an average current of 100 mA. Proposed methods for measuring the transverse and longitudinal profiles will be described. Additionally, a research and development effort using an rf gun as a low-emittance source of electrons for injection into the 200- to 650-MeV linac subsystem is underway. This latter system is projected to produce electron beams with a normalized, rms emittance of ∼2 π mm-mrad at peak currents of near one hundred amps. This interesting characterization problem will also be briefly discussed. The combination of both source types within one laboratory facility will stimulate the development of diagnostic techniques in these parameter spaces

  8. Single-Layer Halide Perovskite Light-Emitting Diodes with Sub-Band Gap Turn-On Voltage and High Brightness.

    Science.gov (United States)

    Li, Junqiang; Shan, Xin; Bade, Sri Ganesh R; Geske, Thomas; Jiang, Qinglong; Yang, Xin; Yu, Zhibin

    2016-10-03

    Charge-carrier injection into an emissive semiconductor thin film can result in electroluminescence and is generally achieved by using a multilayer device structure, which requires an electron-injection layer (EIL) between the cathode and the emissive layer and a hole-injection layer (HIL) between the anode and the emissive layer. The recent advancement of halide perovskite semiconductors opens up a new path to electroluminescent devices with a greatly simplified device structure. We report cesium lead tribromide light-emitting diodes (LEDs) without the aid of an EIL or HIL. These so-called single-layer LEDs have exhibited a sub-band gap turn-on voltage. The devices obtained a brightness of 591 197 cd m -2 at 4.8 V, with an external quantum efficiency of 5.7% and a power efficiency of 14.1 lm W -1 . Such an advancement demonstrates that very high efficiency of electron and hole injection can be obtained in perovskite LEDs even without using an EIL or HIL.

  9. Cesium-enhanced D sup - beam characteristics from a high-brightness volume source

    Energy Technology Data Exchange (ETDEWEB)

    Debiak, T.W. (Grumman Corporate Research Center, Bethpage, NY (USA))

    1991-05-01

    Previous experiments have demonstrated that the H{sup -} beam extracted from a volume ion source may increase by a factor of 4 or more when cesium vapor is introduced into the arc discharge chamber. We have extended these experiments to cesiated D{sup -} beams transported with and without space-charge neutralization by xenon gas. The D{sup -} results show qualitatively similar characteristics to those obtained with H{sup -}. In particular, a factor of almost 7 in current enhancement was obtained compared with noncesiated beams accompanied by a dramatic reduction in electron current. A study of the beam divergence as a function of extracted equivalent current showed that the divergence of the cesiated beams was larger than the uncesiated beams at the same equivalent current. Introduction of xenon gas at a partial pressure of 2.5x10{sup -5} Torr reduced the divergence of the cesiated beams to the value obtained for the uncesiated beams. (orig.).

  10. 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

  11. Generation of Bright Phase-matched Circularly-polarized Extreme Ultraviolet High Harmonics

    Science.gov (United States)

    2014-12-08

    1995). 42. Eichmann , H. et al. Polarization-dependent high-order two-color mixing. Phys. Rev. A 51, R3414–R3417 (1995). 43. Fleischer, A., Kfir, O...calculations of polarization-dependent two- color high-harmonic generation. Phys. Rev. A 52, 2262–2278 (1995). 10. Eichmann , H. et al. polarization

  12. High-energy electron diffraction and microscopy

    CERN Document Server

    Peng, L M; Whelan, M J

    2011-01-01

    This book provides a comprehensive introduction to high energy electron diffraction and elastic and inelastic scattering of high energy electrons, with particular emphasis on applications to modern electron microscopy. Starting from a survey of fundamental phenomena, the authors introduce the most important concepts underlying modern understanding of high energy electron diffraction. Dynamical diffraction in transmission (THEED) and reflection (RHEED) geometries is treated using ageneral matrix theory, where computer programs and worked examples are provided to illustrate the concepts and to f

  13. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  14. Bright x-ray sources from laser irradiation of foams with high concentration of Ti

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, F., E-mail: perez75@llnl.gov; Patterson, J. R.; May, M.; Colvin, J. D.; Biener, M. M.; Wittstock, A.; Kucheyev, S. O.; Charnvanichborikarn, S.; Satcher, J. H.; Gammon, S. A.; Poco, J. F.; Fournier, K. B. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Fujioka, S.; Zhang, Z.; Ishihara, K.; Tanaka, N.; Ikenouchi, T.; Nishimura, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    Low-density foams irradiated by a 20 kJ laser at the Omega laser facility (Laboratory for Laser Energetics, Rochester, NY, USA) are shown to convert more than 5% of the laser energy into 4.6 to 6.0 keV x rays. This record efficiency with foam targets is due to novel fabrication techniques based on atomic-layer-deposition of Ti atoms on an aerogel scaffold. A Ti concentration of 33 at. % was obtained in a foam with a total density of 5 mg/cm{sup 3}. The dynamics of the ionization front through these foams were investigated at the 1 kJ laser of the Gekko XII facility (Institute for Laser Engineering, Osaka, Japan). Hydrodynamic simulations can reproduce the average electron temperature but fail to predict accurately the heat front velocity in the foam. This discrepancy is shown to be unrelated to the possible water adsorbed in the foam but could be attributed to effects of the foam micro-structure.

  15. Production of hollow atoms by high brightness x-ray sources and its applications

    International Nuclear Information System (INIS)

    Moribayashi, Kengo

    2004-01-01

    We study x-ray emissions from the (multi-)inner-shell states and hollow atoms of Si ions excited by high intensity x-ray sources. It is found that the x-ray number from multi-inner-shell excited states (1s 2 2s 2 2p k 3s 2 3p 2 , k=1-4) and hollow atoms (1s 2 2s 2 3p 2 ) is affected greatly by the high intensity short-pulse x-rays and little by weak intensity post-long pulse x-rays. The ratio of the x-ray intensities from hollow atoms to those from the multi-inner-shell excited states becomes almost independent of the pulses and dependent on the intensities of x-ray sources. This ratio may be used for the measurement of intensities of high intensity short pulse x-ray sources. (author)

  16. Bright high-repetition-rate source of narrowband extreme-ultraviolet harmonics beyond 22 eV

    Energy Technology Data Exchange (ETDEWEB)

    Wang, He [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Xu, Yiming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Ulonska, Stefan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Robinson, Joseph S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Ranitovic, Predrag [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Kaindl, Robert A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division

    2015-06-11

    Novel table-top sources of extreme-ultraviolet light based on high-harmonic generation yield unique insight into the fundamental properties of molecules, nanomaterials or correlated solids, and enable advanced applications in imaging or metrology. Extending high-harmonic generation to high repetition rates portends great experimental benefits, yet efficient extreme-ultraviolet conversion of correspondingly weak driving pulses is challenging. In this article, we demonstrate a highly-efficient source of femtosecond extreme-ultraviolet pulses at 50-kHz repetition rate, utilizing the ultraviolet second-harmonic focused tightly into Kr gas. In this cascaded scheme, a photon flux beyond ≈3 × 1013 s-1 is generated at 22.3 eV, with 5 × 10-5 conversion efficiency that surpasses similar harmonics directly driven by the fundamental by two orders-of-magnitude. The enhancement arises from both wavelength scaling of the atomic dipole and improved spatio-temporal phase matching, confirmed by simulations. Finally, spectral isolation of a single 72-meV-wide harmonic renders this bright, 50-kHz extreme-ultraviolet source a powerful tool for ultrafast photoemission, nanoscale imaging and other applications.

  17. Atomic physics with high-brightness synchrotron x-ray sources

    International Nuclear Information System (INIS)

    Jones, K.W.; Johnson, B.M.; Meron, M.

    1985-11-01

    A description of atomic physics experiments that we intend to carry out at the National Synchrotron Light Source is given. Emphasis is given to work that investigates the properties of multiply charged ions. The use of a synchrotron storage ring for highly charged heavy ions is proposed as a way to produce high current beams which will make possible experiments to study the photoexcitation and ionization of multiply charged ions for the first time. Experiments along the same lines which are feasible at the proposed Advanced Light Source are considered briefly. 7 refs., 2 figs

  18. Micro-structure Engineering of InGaN/GaN Quantum Wells for High Brightness Light Emitting Devices

    KAUST Repository

    Shen, Chao

    2013-05-01

    With experimental realization of micro-structures, the feasibility of achieving high brightness, low efficiency droop blue LED was implemented based on InGaN/GaN micro-LED-pillar design. A significantly high current density of 492 A/cm2 in a 20 μm diameter (D) micro-LED-pillar was achieved, compared to that of a 200 μm diameter LED (20 A/cm2), both at 10 V bias voltage. In addition, an increase in sustained quantum efficiency from 70.2% to 83.7% at high injection current density (200 A/cm2) was observed in micro-LED-pillars in conjunction with size reduction from 80 μm to 20 μm. A correlation between the strain relief and the electrical performance improvement was established for micro-LED-pillars with D < 50 μm, apart from current spreading effect. The degree of strain relief and its distribution were further studied in micro-LED-pillars with D ranging from 1 μm to 15 μm. Significant wavenumbers down-shifts for E2 and A1 Raman peaks, together with the blue shifted PL peak emission, were observed in as-prepared pillars, reflecting the degree of strain relief. A sharp transition from strained to relaxed epitaxy region was discernible from the competing E2 phonon peaks at 572 cm-1 and 568 cm-1, which were attributed to strain residue and strain relief, respectively. A uniform strain relief at the center of micro-pillars was achieved, i.e. merging of the competing phonon peaks, after Rapid Thermal Annealing (RTA) at 950℃ for 20 seconds, phenomenon of which was observed for the first time. The transition from maximum strain relief to a uniform strain relief was found along the narrow circumference (< 2.5 μm) of the pillars from the line-map of Raman spectroscopy. The extent of strain relief is also examined considering the height (L) of micro-LED-pillars fabricated using FIB micro-machining technique. The significant strain relief of up to 70% (from -1.4 GPa to -0.37 GPa), with a 71 meV PL peak blue shift, suggested that micro-LED-pillar with D < 3 μm and L

  19. High brightness K+ ion source for heavy ion fusion linear induction accelerators

    International Nuclear Information System (INIS)

    Henestroza, E.; Eylon, S.; Chupp, W.; Rutkowski, H.

    1992-01-01

    Low emittance, high current, singly charged potassium thermionic ion sources are being developed for the Induction Linac System Experiment injector, ILSE. The ILSE, now in study at LBL, will address the physics issues of particle beams in a heavy ion fusion driver scenario. The K + ion beam considered is emitted thermionically into a diode gap from alumino-silicate layers (zeolite) coated on a porous tungsten cup. The Single Beam Transport Experiment (SBTE) 120keV cesium source was redesigned and modified with the aid of an ion optics and gun design program (EGUN) to enable the evaluation of the K + source performance at high extraction currents of about 80mA from a one inch diameter source. The authors report on the source fabrication technique and performance, including total current and current density profile measurements using Faraday cups, phase space distributions using the double slit scanning technique, and source emitting surface temperature dependence on heating power using a wire pyrometer

  20. Coherent combining of high brightness tapered lasers in master oscillator power amplifier configuration

    Science.gov (United States)

    Albrodt, P.; Hanna, M.; Moron, F.; Decker, J.; Winterfeldt, M.; Blume, G.; Erbert, G.; Crump, P.; Georges, P.; Lucas-Leclin, G.

    2018-02-01

    Improved diode laser beam combining techniques are in strong demand for applications in material processing. Coherent beam combining (CBC) is the only combining approach that has the potential to maintain or even improve all laser properties, and thus has high potential for future systems. As part of our ongoing studies into CBC of diode lasers, we present recent progress in the coherent superposition of high-power single-pass tapered laser amplifiers. The amplifiers are seeded by a DFB laser at λ = 976 nm, where the seed is injected into a laterally single-mode ridge-waveguide input section. The phase pistons on each beam are actively controlled by varying the current in the ridge section of each amplifier, using a sequential hill-climbing algorithm, resulting in a combined beam with power fluctuations of below 1%. The currents into the tapered sections of the amplifiers are separately controlled, and remain constant. In contrast to our previous studies, we favour a limited number of individual high-power amplifiers, in order to preserve a high extracted power per emitter in a simple, low-loss coupling arrangement. Specifically, a multi-arm interferometer architecture with only three devices is used, constructed using 6 mm-long tapered amplifiers, mounted junction up on C-mounts, to allow separate contact to single mode and amplifier sections. A maximum coherently combined power of 12.9 W is demonstrated in a nearly diffraction-limited beam, corresponding to a 65% combining efficiency, with power mainly limited by the intrinsic beam quality of the amplifiers. Further increased combined power is currently sought.

  1. Temperature dependence of Ce:YAG single-crystal phosphors for high-brightness white LEDs/LDs

    Science.gov (United States)

    Arjoca, Stelian; Víllora, Encarnación G.; Inomata, Daisuke; Aoki, Kazuo; Sugahara, Yoshiyuki; Shimamura, Kiyoshi

    2015-05-01

    The growth of Ce:Y3Al5O12(Ce:YAG) single-crystal phosphors (SCPs) by the Czochralski technique is analyzed in terms of segregation coefficient, solubility and absorption cross-section. The emission characteristics of these SCPs are investigated in a wide temperature range, from liquid He temperature up to 500 °C. The internal quantum efficiency of SCPs achieves its maximum at about 250 °C. Thermal quenching of SCPs at high temperature is attributed to the Mott-Seitz mechanism. In the case of ceramic powder phosphors, a continuous droop is observed with the temperature due to defect-related non-radiative recombination paths. It is shown that (Ce:YAG SCPs + blue LEDs/LDs) can cover a wide range of color temperatures 5500-7000 K, with color rendering indices around 70. In conclusion, it is shown that Ce:YAG SCPs are the most efficient and temperature stable converters to fabricate high-brightness white light sources with high-power blue LEDs and LDs.

  2. Bright upconversion luminescence and increased Tc in CaBi2Ta2O9:Er high temperature piezoelectric ceramics

    International Nuclear Information System (INIS)

    Peng Dengfeng; Wang Xusheng; Yao Xi; Xu Chaonan; Lin Jian; Sun Tiantuo

    2012-01-01

    Er 3+ doped CaBi 2 Ta 2 O 9 (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er 3+ doped CBT ceramics were investigated as a function of Er 3+ concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from 4 S 3/2 and 4 F 9/2 to 4 I 15/2 , respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  3. Testing Snow Melt Algorithms in High Relief Topography Using Calibrated Enhanced-Resolution Brightness Temperatures, Hunza River Basin, Pakistan

    Science.gov (United States)

    Ramage, J. M.; Brodzik, M. J.; Hardman, M.; Troy, T. J.

    2017-12-01

    Snow is a vital part of the terrestrial hydrological cycle, a crucial resource for people and ecosystems. In mountainous regions snow is extensive, variable, and challenging to document. Snow melt timing and duration are important factors affecting the transfer of snow mass to soil moisture and runoff. Passive microwave brightness temperature (Tb) changes at 36 and 18 GHz are a sensitive way to detect snow melt onset due to their sensitivity to the abrupt change in emissivity. They are widely used on large icefields and high latitude watersheds. The coarse resolution ( 25 km) of historically available data has precluded effective use in high relief, heterogeneous regions, and gaps between swaths also create temporal data gaps at lower latitudes. New enhanced resolution data products generated from a scatterometer image reconstruction for radiometer (rSIR) technique are available at the original frequencies. We use these Calibrated Enhanced-resolution Brightness (CETB) Temperatures Earth System Data Records (ESDR) to evaluate existing snow melt detection algorithms that have been used in other environments, including the cross polarized gradient ratio (XPGR) and the diurnal amplitude variations (DAV) approaches. We use the 36/37 GHz (3.125 km resolution) and 18/19 GHz (6.25 km resolution) vertically and horizontally polarized datasets from the Special Sensor Microwave Imager (SSM/I) and Advanced Microwave Radiometer for EOS (AMSR-E) and evaluate them for use in this high relief environment. The new data are used to assess glacier and snow melt records in the Hunza River Basin [area 13,000 sq. km, located at 36N, 74E], a tributary to the Upper Indus Basin, Pakistan. We compare the melt timing results visually and quantitatively to the corresponding EASE-Grid 2.0 25-km dataset, SRTM topography, and surface temperatures from station and reanalysis data. The new dataset is coarser than the topography, but is able to differentiate signals of melt/refreeze timing for

  4. 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

  5. Proper design of silica nanoparticles combines high brightness, lack of cytotoxicity and efficient cell endocytosis

    Science.gov (United States)

    Rampazzo, Enrico; Voltan, Rebecca; Petrizza, Luca; Zaccheroni, Nelsi; Prodi, Luca; Casciano, Fabio; Zauli, Giorgio; Secchiero, Paola

    2013-08-01

    leukemic cell line and primary normal peripheral blood mononuclear cells) or in adherence (human hepatocarcinoma Huh7 and umbilical vein endothelial cells). Moreover, by multiparametric flow cytometry, we could demonstrate that the highest efficiency of cell uptake and entry was observed with NP-PEG-amino, with a stable persistence of the fluorescence signal associated with SiNPs in the loaded cell populations both in vitro and in vivo settings suggesting this as an innovative method for cell traceability and detection in whole organisms. Finally, experiments performed with the endocytosis inhibitor Genistein clearly suggested the involvement of a caveolae-mediated pathway in SiNP endocytosis. Overall, these data support the safe use of these SiNPs for diagnostic and therapeutic applications. Electronic supplementary information (ESI) available: Synthetic procedures, 1H and 13C NMR spectra, TEM and DLS measurements, and absorption and emission spectra. See DOI: 10.1039/c3nr02563b

  6. Physical conditions of the interstellar medium in high-redshift submillimetre bright galaxies

    Science.gov (United States)

    Yang, Chentao

    2017-12-01

    The discovery of a population of high- redshift dust-obscured submillimeter galaxies (SMGs) from ground-based submm cameras has revolutionised our understanding of galaxy evolution and star formation in extreme conditions. They are the strongest starbursts in the Universe approaching the Eddington limit and are believed to be the progenitors of the most massive galaxies today. However, theoretical models of galaxy evolution have even been challenged by a large number of detections of high-redshift SMGs. A very few among them are gravitationally lensed by an intervening galaxy. Recent wide-area extragalactic surveys have discovered hundreds of such strongly lensed SMGs, opening new exciting opportunities for observing the interstellar medium in these exceptional objects. We have thus carefully selected a sample of strongly gravitational lensed SMGs based on the submillimeter flux limit from the Herschel-ATLAS sample. Using IRAM telescopes, we have built a rich H2O-line-detected sample of 16 SMGs. We found a close-to-linear tight correlation between the H2O line and total infrared luminosity. This indicates the importance of far-IR pumping to the excitation of the H2O lines. Using a far-IR pumping model, we have derived the physical properties of the H2O gas and the dust. We showed that H2O lines trace a warm dense gas that may be closely related to the active star formation. Along with the H2O lines, several H2O+ lines have also been detected in three of our SMGs. We also find a tight correlation between the luminosity of the lines of H2O and H2O+ from local ULIRGs to high-redshift SMGs. The flux ratio between H2O+ and H2O suggests that cosmic rays from strong star forming activities are possibly driving the related oxygen chemistry. Another important common molecular gas tracer is the CO line. We have observed multiple transitions of the CO lines in each of our SMGs with IRAM 30m telescope. By analysing the CO line profile, we discovered a significant differential

  7. Astigmatism-free high-brightness 1060 nm edge-emitting lasers with narrow circular beam profile.

    Science.gov (United States)

    Miah, Md Jarez; Kalosha, Vladimir P; Bimberg, Dieter; Pohl, Johannes; Weyers, Markus

    2016-12-26

    1060 nm high-brightness vertical broad-area edge-emitting lasers providing anastigmatic high optical power into a narrow circular beam profile are demonstrated. Ridge-waveguide (RW) lasers yield record 2.2 W single-transverse mode power in the 1060-nm wavelength range under continuous-wave (cw) operation at room temperature with excellent beam quality factor M2 ≤ 2. Independent of operating current the astigmatism is only 2.5 µm. 3 mm long broad-area (BA) lasers produce a θvert as narrow as 9° full width at half maximum, which agrees well with our simulation results, being insensitive to drive current. 5 mm long BA lasers deliver highest ever reported cw 12 W multimode output power among lasers showing θvert <10° in the 1060-nm wavelength range. The emitted laser beams from both RW and BA lasers show a perfect circular shape with ≤10° divergence angle at record 2.1 W and 4.2 W cw-mode output power, respectively.

  8. GALEX FAR-ULTRAVIOLET COLOR SELECTION OF UV-BRIGHT HIGH-REDSHIFT QUASARS

    International Nuclear Information System (INIS)

    Worseck, Gabor; Prochaska, J. Xavier

    2011-01-01

    We study the small population of high-redshift (z em >2.7) quasars detected by the Galaxy Evolution Explorer(GALEX), whose far-UV emission is not extinguished by intervening H I Lyman limit systems. These quasars are of particular importance to detect intergalactic He II absorption along their sight lines. We correlate almost all verified z em >2.7 quasars to the GALEX GR4 source catalog covering ∼ 25,000 deg 2 , yielding 304 sources detected at signal-to-noise ratio (S/N) >3. However, ∼50% of these are only detected in the GALEX NUV band, signaling the truncation of the FUV flux by low-redshift optically thick Lyman limit systems. We exploit the GALEX UV color m FUV - m NUV to cull the most promising targets for follow-up studies, with blue (red) GALEX colors indicating transparent (opaque) sight lines. Extensive Monte Carlo simulations indicate an He II detection rate of ∼60% for quasars with m FUV - m NUV ∼ em ∼ 3 to be most promising for Hubble Space Telescope follow-up, with an additional 114 quasars if we consider S/N >2 detections in the FUV. Combining the statistical properties of H I absorbers with the Sloan Digital Sky Survey (SDSS) quasar luminosity function, we predict a large all-sky population of ∼200 quasars with z em >2.7 and i ∼ 304 em ∼ em ∼ em ∼< 3.5 quasars have likely underestimated their space density by selecting intergalactic medium sight lines with an excess of strong H I absorbers.

  9. High electron mobility InN

    International Nuclear Information System (INIS)

    Jones, R. E.; Li, S. X.; Haller, E. E.; van Genuchten, H. C. M.; Yu, K. M.; Ager, J. W. III; Liliental-Weber, Z.; Walukiewicz, W.; Lu, H.; Schaff, W. J.

    2007-01-01

    Irradiation of InN films with 2 MeV He + ions followed by thermal annealing below 500 deg. C creates films with high electron concentrations and mobilities, as well as strong photoluminescence. Calculations show that electron mobility in irradiated samples is limited by triply charged donor defects. Subsequent thermal annealing removes a fraction of the defects, decreasing the electron concentration. There is a large increase in electron mobility upon annealing; the mobilities approach those of the as-grown films, which have 10 to 100 times smaller electron concentrations. Spatial ordering of the triply charged defects is suggested to cause the unusual increase in electron mobility

  10. Comparison of 3D cellular imaging techniques based on scanned electron probes: Serial block face SEM vs. Axial bright-field STEM tomography.

    Science.gov (United States)

    McBride, E L; Rao, A; Zhang, G; Hoyne, J D; Calco, G N; Kuo, B C; He, Q; Prince, A A; Pokrovskaya, I D; Storrie, B; Sousa, A A; Aronova, M A; Leapman, R D

    2018-06-01

    Microscopies based on focused electron probes allow the cell biologist to image the 3D ultrastructure of eukaryotic cells and tissues extending over large volumes, thus providing new insight into the relationship between cellular architecture and function of organelles. Here we compare two such techniques: electron tomography in conjunction with axial bright-field scanning transmission electron microscopy (BF-STEM), and serial block face scanning electron microscopy (SBF-SEM). The advantages and limitations of each technique are illustrated by their application to determining the 3D ultrastructure of human blood platelets, by considering specimen geometry, specimen preparation, beam damage and image processing methods. Many features of the complex membranes composing the platelet organelles can be determined from both approaches, although STEM tomography offers a higher ∼3 nm isotropic pixel size, compared with ∼5 nm for SBF-SEM in the plane of the block face and ∼30 nm in the perpendicular direction. In this regard, we demonstrate that STEM tomography is advantageous for visualizing the platelet canalicular system, which consists of an interconnected network of narrow (∼50-100 nm) membranous cisternae. In contrast, SBF-SEM enables visualization of complete platelets, each of which extends ∼2 µm in minimum dimension, whereas BF-STEM tomography can typically only visualize approximately half of the platelet volume due to a rapid non-linear loss of signal in specimens of thickness greater than ∼1.5 µm. We also show that the limitations of each approach can be ameliorated by combining 3D and 2D measurements using a stereological approach. Copyright © 2018. Published by Elsevier Inc.

  11. Stable high brightness radio frequency driven micro-discharge lamps at 193 (ArF*) and 157 nm ( F2*)

    International Nuclear Information System (INIS)

    Salvermoser, M; Murnick, D E

    2004-01-01

    A stable discharge between two pin electrodes separated by several hundred micrometres in a high pressure rare gas (∼900 mbar) halogen (∼1 mbar) mixture is shown to yield continuous wave (CW) ultra violet (UV) and vacuum UV light sources. Lamps operating at 193 (ArF*) and 157 nm F 2 *) have been demonstrated. Total CW output power in the UV was measured to be 30 for ArF* and 20 mW for F 2 *. The brightness of the light sources is estimated to be of the order of several W cm -2 sr -1 . With direct current excitation, electrode lifetimes are limited to a few minutes due to fluorine salt deposits. However, using a radio frequency (RF) field to drive the discharge, the lifetime of the lamps increased to hundreds of hours. A one-dimensional model of the RF micro-discharge explaining the increase in electrode lifetime is presented. The technology described can be adapted to many other wavelengths and promises even higher powers in future

  12. Numerical simulation of a high-brightness lithium ion gun for a Zeeman polarimetry on JT-60U

    International Nuclear Information System (INIS)

    Kojima, Atsushi; Kamiya, Kensaku; Fujita, Takaaki; Kamada, Yutaka; Iguchi, Harukazu

    2007-01-01

    A lithium ion gun is under construction for a lithium beam Zeeman polarimetry on JT-60U. The performance of the prototype ion gun has been estimated by the numerical simulation taking the space charge effects into account. The target values of the ion gun are the beam energy of 30 keV, the beam current of 10 mA and the beam divergence angle within 0.13 degrees. The low divergence of 0.13 degrees is required for the geometry of the Zeeman polarimetry on JT-60U where the observation area is 6.5 m away from the neutralizer. The numerical simulation needs to be carried out for the design study because the requirement of the divergence angle is severe for the development of the high-brightness ion gun. The simulation results show the beam loss of 50% caused by the clash to the electrode such as the cathode and the neutralizer. Moreover, the beam transport efficiency from the neutralizer to the observation area is low due to the broadening of the divergence angle. The total beam efficiency is about 5%. Extracted beam profile affects the beam focusing and the efficiency. The peaked profile achieves better efficiency than the hollow one. As a result, beam current of 1 mA is obtained at the observation area by the simulation for the prototype ion gun. (author)

  13. Photoluminescence, energy transfer and tunable color of Ce(3+), Tb(3+) and Eu(2+) activated oxynitride phosphors with high brightness.

    Science.gov (United States)

    Lü, Wei; Huo, Jiansheng; Feng, Yang; Zhao, Shuang; You, Hongpeng

    2016-06-21

    New tuneable light-emitting Ca3Al8Si4O17N4:Ce(3+)/Tb(3+)/Eu(2+) oxynitride phosphors with high brightness have been prepared. When doped with trivalent cerium or divalent europium they present blue luminescence under UV excitation. The energy transfer from Ce(3+) to Tb(3+) and Ce(3+) to Eu(2+) ions is deduced from the spectral overlap between Ce(3+) emission and Tb(3+)/Eu(2+) excitation spectra. The energy-transfer efficiencies and corresponding mechanisms are discussed in detail, and the mechanisms of energy transfer from the Ce(3+) to Tb(3+) and Ce(3+) to Eu(2+) ions are demonstrated to be a dipole-quadrupole and dipole-dipole mechanism, respectively, by the Inokuti-Hirayama model. The International Commission on Illumination value of color tuneable emission as well as luminescence quantum yield (23.8-80.6%) can be tuned by controlling the content of Ce(3+), Tb(3+) and Eu(2+). All results suggest that they are suitable for UV light-emitting diode excitation.

  14. Differential responses to high- and low-dose ultraviolet-B stress in tobacco Bright Yellow-2 cells

    Science.gov (United States)

    Takahashi, Shinya; Kojo, Kei H.; Kutsuna, Natsumaro; Endo, Masaki; Toki, Seiichi; Isoda, Hiroko; Hasezawa, Seiichiro

    2015-01-01

    Ultraviolet (UV)-B irradiation leads to DNA damage, cell cycle arrest, growth inhibition, and cell death. To evaluate the UV-B stress–induced changes in plant cells, we developed a model system based on tobacco Bright Yellow-2 (BY-2) cells. Both low-dose UV-B (low UV-B: 740 J m−2) and high-dose UV-B (high UV-B: 2960 J m−2) inhibited cell proliferation and induced cell death; these effects were more pronounced at high UV-B. Flow cytometry showed cell cycle arrest within 1 day after UV-B irradiation; neither low- nor high-UV-B–irradiated cells entered mitosis within 12 h. Cell cycle progression was gradually restored in low-UV-B–irradiated cells but not in high-UV-B–irradiated cells. UV-A irradiation, which activates cyclobutane pyrimidine dimer (CPD) photolyase, reduced inhibition of cell proliferation by low but not high UV-B and suppressed high-UV-B–induced cell death. UV-B induced CPD formation in a dose-dependent manner. The amounts of CPDs decreased gradually within 3 days in low-UV-B–irradiated cells, but remained elevated after 3 days in high-UV-B–irradiated cells. Low UV-B slightly increased the number of DNA single-strand breaks detected by the comet assay at 1 day after irradiation, and then decreased at 2 and 3 days after irradiation. High UV-B increased DNA fragmentation detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay 1 and 3 days after irradiation. Caffeine, an inhibitor of ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) checkpoint kinases, reduced the rate of cell death in high-UV-B–irradiated cells. Our data suggest that low-UV-B–induced CPDs and/or DNA strand-breaks inhibit DNA replication and proliferation of BY-2 cells, whereas larger contents of high-UV-B–induced CPDs and/or DNA strand-breaks lead to cell death. PMID:25954287

  15. Does low surface brightness mean low density?

    NARCIS (Netherlands)

    deBlok, WJG; McGaugh, SS

    1996-01-01

    We compare the dynamical properties of two galaxies at identical positions on the Tully-Fisher relation, but with different surface brightnesses. We find that the low surface brightness galaxy UGC 128 has a higher mass-to-light ratio, and yet has lower mass densities than the high surface brightness

  16. High perveance electron gun for the electron cooling system

    International Nuclear Information System (INIS)

    Korotaev, Yu.; Meshkov, I.; Petrov, A.; Sidorin, A.; Smirnov, A.; Syresin, E.; Titkova, I.

    2000-01-01

    The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 μA/V 3/2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual)

  17. High perveance electron gun for the electron cooling system

    CERN Document Server

    Korotaev, Yu V; Petrov, A; Sidorin, A; Smirnov, A; Syresin, E M; Titkova, I

    2000-01-01

    The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 mu A/V sup 3 sup / sup 2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual).

  18. Relativistic electron mirrors from high intensity laser nanofoil interactions

    International Nuclear Information System (INIS)

    Kiefer, Daniel

    2012-01-01

    The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ 2 , where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

  19. Relativistic electron mirrors from high intensity laser nanofoil interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kiefer, Daniel

    2012-12-21

    The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

  20. High brightness InP micropillars grown on silicon with Fermi level splitting larger than 1 eV.

    Science.gov (United States)

    Tran, Thai-Truong D; Sun, Hao; Ng, Kar Wei; Ren, Fan; Li, Kun; Lu, Fanglu; Yablonovitch, Eli; Chang-Hasnain, Constance J

    2014-06-11

    The growth of III-V nanowires on silicon is a promising approach for low-cost, large-scale III-V photovoltaics. However, performances of III-V nanowire solar cells have not yet been as good as their bulk counterparts, as nanostructured light absorbers are fundamentally challenged by enhanced minority carriers surface recombination rates. The resulting nonradiative losses lead to significant reductions in the external spontaneous emission quantum yield, which, in turn, manifest as penalties in the open-circuit voltage. In this work, calibrated photoluminescence measurements are utilized to construct equivalent voltage-current characteristics relating illumination intensities to Fermi level splitting ΔF inside InP microillars. Under 1 sun, we show that splitting can exceed ΔF ∼ 0.90 eV in undoped pillars. This value can be increased to values of ΔF ∼ 0.95 eV by cleaning pillar surfaces in acidic etchants. Pillars with nanotextured surfaces can yield splitting of ΔF ∼ 0.90 eV, even though they exhibit high densities of stacking faults. Finally, by introducing n-dopants, ΔF of 1.07 eV can be achieved due to a wider bandgap energy in n-doped wurzite InP, the higher brightness of doped materials, and the extraordinarily low surface recombination velocity of InP. This is the highest reported value for InP materials grown on a silicon substrate. These results provide further evidence that InP micropillars on silicon could be a promising material for low-cost, large-scale solar cells with high efficiency.

  1. High temperature electronic gain device

    International Nuclear Information System (INIS)

    McCormick, J.B.; Depp, S.W.; Hamilton, D.J.; Kerwin, W.J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments is described. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube

  2. Impulsive and long duration high-energy gamma-ray emission from the very bright 2012 March 7 solar flares

    Energy Technology Data Exchange (ETDEWEB)

    Ajello, M. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Albert, A.; Allafort, A.; Caliandro, G. A.; Cameron, R. A.; Charles, E. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L. [Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D.; Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bissaldi, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, and Università di Trieste, I-34127 Trieste (Italy); Bonamente, E.; Cecchi, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brigida, M. [Dipartimento di Fisica " M. Merlin" dell' Università e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, Palaiseau (France); Buehler, R. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Caraveo, P. A., E-mail: nicola.omodei@stanford.edu, E-mail: vahep@stanford.edu, E-mail: melissa.pesce.rollins@pi.infn.it [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, I-20133 Milano (Italy); and others

    2014-07-01

    The Fermi Large Area Telescope (LAT) detected gamma-rays up to 4 GeV from two bright X-class solar flares on 2012 March 7, showing both an impulsive and temporally extended emission phases. The gamma-rays appear to originate from the same active region as the X-rays associated with these flares. The >100 MeV gamma-ray flux decreases monotonically during the first hour (impulsive phase) followed by a slower decrease for the next 20 hr. A power law with a high-energy exponential cutoff can adequately describe the photon spectrum. Assuming that the gamma rays result from the decay of pions produced by accelerated protons and ions with a power-law spectrum, we find that the index of that spectrum is ∼3, with minor variations during the impulsive phase. During the extended phase the photon spectrum softens monotonically, requiring the proton index varying from ∼4 to >5. The >30 MeV proton flux observed by the GOES satellites also shows a flux decrease and spectral softening, but with a harder spectrum (index ∼2-3). Based on these observations, we explore the relative merits of prompt or continuous acceleration scenarios, hadronic or leptonic emission processes, and acceleration at the solar corona or by the fast coronal mass ejections. We conclude that the most likely scenario is continuous acceleration of protons in the solar corona that penetrate the lower solar atmosphere and produce pions that decay into gamma rays. However, acceleration in the downstream of the shock cannot be definitely ruled out.

  3. Continued advances in high brightness fiber-coupled laser modules for efficient pumping of fiber and solid-state lasers

    Science.gov (United States)

    Hemenway, M.; Chen, Z.; Urbanek, W.; Dawson, D.; Bao, L.; Kanskar, M.; DeVito, M.; Martinsen, R.

    2018-02-01

    Both the fibber laser and diode-pumped solid-state laser market continue to drive advances in pump diode module brightness. We report on the continued progress by nLIGHT to develop and deliver the highest brightness diode-laser pumps using single-emitter technology. Continued advances in multimode laser diode technology [13] and fiber-coupling techniques have enabled higher emitter counts in the element packages, enabling us to demonstrate 305 W into 105 μm - 0.16 NA. This brightness improvement is achieved by leveraging our prior-reported package re-optimization, allowing an increase in the emitter count from two rows of nine emitters to two rows of twelve emitters. Leveraging the two rows off twelve emitter architecture,, product development has commenced on a 400 W into 200 μm - 00.16 NA package. Additionally, the advances in pump technology intended for CW Yb-doped fiber laser pumping has been leveraged to develop the highest brightness 793 nm pump modules for 2 μm Thulium fiber laser pumping, generating 150 W into 200 μm - 0.18 NA and 100 W into 105 μm - 0.15 NA. Lastly, renewed interest in direct diode materials processing led us to experiment with wavelength multiplexing our existing state of the art 200 W, 105 μm - 00.15 NA package into a combined output of 395 WW into 105 μm - 0.16 NA.

  4. High energy electron positron physics

    International Nuclear Information System (INIS)

    Ali, A.; Soding, P.

    1987-01-01

    With the termination of the physics program at PETRA in a year from now, and with the start of TRISTAN and the SLC and later LEP, an era of e/sup +/e/sup -/ physics will come to an end and a new one begins. The field is changing from a field of a few specialists, to becoming one of the mainstream efforts of the high energy community. It seems appropriate at this moment to summarize what has been learned over the past years, in a way more useful to any high energy physicist in particular to newcomers in the e/sup +/e/sup -/ field. This is the purpose of the book. This book should be used as a reference for future workers in the field of e/sup +/e/sup -/ interactions. It includes the most relevant data, parametrizations, theoretical background, and a chapter on detectors. Contents: Foreword; Detectors for High Energy e/sup +/e/sup -/ Physics; Lepton Pair Production and Electroweak Parameters; Hadron Production, Strong and Electroweak Properties; tau Physics; Recent Results on the Charm Sector; Bottom Physics; Lifetime Measurements of tau, Charmed and Beauty Hadrons; Υ Spectroscopy; Hadronic Decays of the Υ; Quark and Gluon Fragmentation in the e/sup +/e/sup -/ Continuum; Jet Production and QCD; Two Photon Physics; Search for New Particles

  5. High energy electron multibeam diffraction and imaging

    International Nuclear Information System (INIS)

    Bourret, Alain.

    1980-04-01

    The different theories of dynamical scattering of electrons are firstly reviewed with special reference to their basis and the validity of the different approximations. Then after a short description of the different experimental set ups, structural analysis and the investigation of the optical potential by means of high energy electrons will be surveyed

  6. Highly stable single-crystal LaB6 cathode for conventional electron microprobe instruments

    International Nuclear Information System (INIS)

    Shimizu, R.; Shinike, T.; Ichimura, S.; Kawaii, S.; Tanaka, T.

    1978-01-01

    The performance of single-crystal LaB 6 cathode was examined by measuring the brightness and current stability under the same conditions as for the conventional W hairpin cathode. The LaB 6 cathode was mounted in Vogel-type electron gun assembly of an electron probe microanalyser JAX-3 specifically modified for this purpose. The result shows that the present LaB 6 cathode provides not only high brightness of 2 x 10 5 A/cm 2 str. at 20 kV, but also high-current stability better than 1 x 10 - 3 Ah - 1 in standard operation without any specific aid for current stabilization. Thus an order of magnitude increase in both the brightness and service lifetime can easily be obtained provided that the vacuum of the system is adequate, namely better than 1 x 10 - 5 Torr (1.33 x 10 - 3 Pa). This substantial improvement of the present single-crystal LaB 6 cathode over the conventional W hairpin was also confirmed in a practical way by use in a commercial-type scanning Auger electron microscope, JAMP III

  7. High-efficient electron linacs

    International Nuclear Information System (INIS)

    Glavatskikh, K.V.; Zverev, B.V.; Kalyuzhnyj, V.E.; Morozov, V.L.; Nikolaev, S.V.; Plotnikov, S.N.; Sobenin, N.P.; Vovna, V.A.; Gryzlov, A.V.

    1993-01-01

    Comparison analysis of ELA on running and still waves designed for 10 MeV energy and with high efficiency is carried out. It is shown, that from the point of view of dimensions ELA with a still wave or that of a combined type is more preferable. From the point of view of impedance characteristics in any variant with application of magnetron as HF-generator it is necessary to implement special requirements to the accelerating structure if no ferrite isolation is provided in HF-channel. 3 refs., 4 figs., 1 tab

  8. Development of a high average current polarized electron source with long cathode operational lifetime

    Energy Technology Data Exchange (ETDEWEB)

    C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

    2007-02-01

    Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  9. Generation of Bright, Spatially Coherent Soft X-Ray High Harmonics in a Hollow Waveguide Using Two-Color Synthesized Laser Pulses.

    Science.gov (United States)

    Jin, Cheng; Stein, Gregory J; Hong, Kyung-Han; Lin, C D

    2015-07-24

    We investigate the efficient generation of low-divergence high-order harmonics driven by waveform-optimized laser pulses in a gas-filled hollow waveguide. The drive waveform is obtained by synthesizing two-color laser pulses, optimized such that highest harmonic yields are emitted from each atom. Optimization of the gas pressure and waveguide configuration has enabled us to produce bright and spatially coherent harmonics extending from the extreme ultraviolet to soft x rays. Our study on the interplay among waveguide mode, atomic dispersion, and plasma effect uncovers how dynamic phase matching is accomplished and how an optimized waveform is maintained when optimal waveguide parameters (radius and length) and gas pressure are identified. Our analysis should help laboratory development in the generation of high-flux bright coherent soft x rays as tabletop light sources for applications.

  10. Multi-kW high-brightness fiber coupled diode laser based on two dimensional stacked tailored diode bars

    Science.gov (United States)

    Bayer, Andreas; Unger, Andreas; Köhler, Bernd; Küster, Matthias; Dürsch, Sascha; Kissel, Heiko; Irwin, David A.; Bodem, Christian; Plappert, Nora; Kersten, Maik; Biesenbach, Jens

    2016-03-01

    The demand for high brightness fiber coupled diode laser devices in the multi kW power region is mainly driven by industrial applications for materials processing, like brazing, cladding and metal welding, which require a beam quality better than 30 mm x mrad and power levels above 3kW. Reliability, modularity, and cost effectiveness are key factors for success in the market. We have developed a scalable and modular diode laser architecture that fulfills these requirements through use of a simple beam shaping concept based on two dimensional stacking of tailored diode bars mounted on specially designed, tap water cooled heat sinks. The base element of the concept is a tailored diode laser bar with an epitaxial and lateral structure designed such that the desired beam quality in slow-axis direction can be realized without using sophisticated beam shaping optics. The optical design concept is based on fast-axis collimator (FAC) and slow-axis collimator (SAC) lenses followed by only one additional focusing optic for efficient coupling into a 400 μm fiber with a numerical aperture (NA) of 0.12. To fulfill the requirements of scalability and modularity, four tailored bars are populated on a reduced size, tap water cooled heat sink. The diodes on these building blocks are collimated simply via FAC and SAC. The building blocks can be stacked vertically resulting in a two-dimensional diode stack, which enables a compact design of the laser source with minimum beam path length. For a single wavelength, up to eight of these building blocks, implying a total of 32 tailored bars, can be stacked into a submodule, polarization multiplexed, and coupled into a 400 μm, 0.12NA fiber. Scalability into the multi kW region is realized by wavelength combining of replaceable submodules in the spectral range from 900 - 1100 nm. We present results of a laser source based on this architecture with an output power of more than 4 kW and a beam quality of 25 mm x mrad.

  11. Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Feist, Armin; Bach, Nora; Rubiano da Silva, Nara; Danz, Thomas; Möller, Marcel; Priebe, Katharina E.; Domröse, Till; Gatzmann, J. Gregor; Rost, Stefan; Schauss, Jakob; Strauch, Stefanie; Bormann, Reiner; Sivis, Murat; Schäfer, Sascha, E-mail: sascha.schaefer@phys.uni-goettingen.de; Ropers, Claus, E-mail: claus.ropers@uni-goettingen.de

    2017-05-15

    We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9 Å focused beam diameter, 200 fs pulse duration and 0.6 eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams. - Highlights: • First implementation of an ultrafast TEM employing a nanoscale photocathode. • Localized single photon-photoemission from nanoscopic field emitter yields low emittance ultrashort electron pulses. • Electron pulses focused down to ~9 Å, with a duration of 200 fs and an energy width of 0.6 eV are demonstrated. • Quantitative characterization of ultrafast electron gun emittance and brightness. • A range of applications of high coherence ultrashort electron pulses is shown.

  12. 1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

    Science.gov (United States)

    Hansen, A. K.; Christensen, M.; Noordegraaf, D.; Heist, P.; Papastathopoulos, E.; Loyo-Maldonado, V.; Jensen, O. B.; Stock, M. L.; Skovgaard, P. M. W.

    2017-02-01

    Semiconductor lasers are ideal sources for efficient electrical-to-optical power conversion and for many applications where their small size and potential for low cost are required to meet market demands. Yellow lasers find use in a variety of bio-related applications, such as photocoagulation, imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction- limited, single frequency operation with output powers up to 8 W near 1120 nm. We present a 1.9 W single frequency laser system at 562 nm, based on single pass cascaded frequency doubling of such a tapered laser diode. The laser diode is a monolithic device consisting of two sections: a ridge waveguide with a distributed Bragg reflector, and a tapered amplifier. Using single-pass cascaded frequency doubling in two periodically poled lithium niobate crystals, 1.93 W of diffraction-limited light at 562 nm is generated from 5.8 W continuous-wave infrared light. When turned on from cold, the laser system reaches full power in just 60 seconds. An advantage of using a single pass configuration, rather than an external cavity configuration, is increased stability towards external perturbations. For example, stability to fluctuating case temperature over a 30 K temperature span has been demonstrated. The combination of high stability, compactness and watt-level power range means this technology is of great interest for a wide range of biological and biomedical applications.

  13. A multi-scale and model approach to estimate future tidal high water statistics in the southern German Bright

    Science.gov (United States)

    Hein, H.; Mai, S.; Mayer, B.; Pohlmann, T.; Barjenbruch, U.

    2012-04-01

    The interactions of tides, external surges, storm surges and waves with an additional role of the coastal bathymetry define the probability of extreme water levels at the coast. Probabilistic analysis and also process based numerical models allow the estimation of future states. From the physical point of view both, deterministic processes and stochastic residuals are the fundamentals of high water statistics. This study uses a so called model chain to reproduce historic statistics of tidal high water levels (Thw) as well as the prediction of future statistics high water levels. The results of the numerical models are post-processed by a stochastic analysis. Recent studies show, that for future extrapolation of extreme Thw nonstationary parametric approaches are required. With the presented methods a better prediction of time depended parameter sets seems possible. The investigation region of this study is the southern German Bright. The model-chain is the representation of a downscaling process, which starts with an emissions scenario. Regional atmospheric and ocean models refine the results of global climate models. The concept of downscaling was chosen to resolve coastal topography sufficiently. The North Sea and estuaries are modeled with the three-dimensional model HAMburg Shelf Ocean Model. The running time includes 150 years (1950 - 2100). Results of four different hindcast runs and also of one future prediction run are validated. Based on multi-scale analysis and the theory of entropy we analyze whether any significant periodicities are represented numerically. Results show that also hindcasting the climate of Thw with a model chain for the last 60 years is a challenging task. For example, an additional modeling activity must be the inclusion of tides into regional climate ocean models. It is found that the statistics of climate variables derived from model results differs from the statistics derived from measurements. E.g. there are considerable shifts in

  14. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  15. 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.

  16. Diagnostic for a high-repetition rate electron photo-gun and first measurements

    Science.gov (United States)

    Filippetto, D.; Doolittle, L.; Huang, G.; Norum, E.; Portmann, G.; Qian, H.; Sannibale, F.

    2015-05-01

    The APEX electron source at LBNL combines the high-repetition-rate with the high beam brightness typical of photoguns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment, opening the doors of the high average power to brightness-hungry applications as X-Ray FELs, MHz ultrafast electron diffraction etc.. As first step, a complete characterization of the beam parameters is foreseen at the Gun beam energy of 750 keV. Diagnostics for low and high current measurements have been installed and tested, and measurements of cathode lifetime and thermal emittance in a RF environment with mA current performed. The recent installation of a double slit system, a deflecting cavity and a high precision spectrometer, allow the exploration of the full 6D phase space. Here we discuss the present layout of the machine and future upgrades, showing the latest results at low and high repetition rate, together with the tools and techniques used.

  17. High-field electron-photon interactions

    International Nuclear Information System (INIS)

    Hartemann, F V.

    1999-01-01

    Recent advances in novel technologies (including chirped-pulse amplification, femtosecond laser systems operating in the TW-PW range, high-gradient rf photoinjectors, and synchronized relativistic electron bunches with subpicosecond durations and THz bandwidths) allow experimentalists to study the interaction of relativistic electrons with ultrahigh-intensity photon fields. Ponderomotive scattering can accelerate these electrons with extremely high gradients in a three-dimensional vacuum laser focus. The nonlinear Doppler shift induced by relativistic radiation pressure in Compton backscattering is shown to yield complex nonlinear spectra which can be modified by using temporal laser pulse shaping techniques. Colliding laser pulses, where ponderomotive acceleration and Compton backscattering are combined, could also yield extremely short wavelength photons. Finally, one expects strong radiative corrections when the Doppler-upshifted laser wavelength approaches the Compton scale. These are discussed within the context of high-field classical electrodynamics, a new discipline borne out of the aforementioned innovations

  18. Bright point study

    International Nuclear Information System (INIS)

    Tang, F.; Harvey, K.; Bruner, M.; Kent, B.; Antonucci, E.

    1982-01-01

    Transition region and coronal observations of bright points by instruments aboard the Solar Maximum Mission and high resolution photospheric magnetograph observations on September 11, 1980 are presented. A total of 31 bipolar ephemeral regions were found in the photosphere from birth in 9.3 hours of combined magnetograph observations from three observatories. Two of the three ephemeral regions present in the field of view of the Ultraviolet Spectrometer-Polarimeter were observed in the C IV 1548 line. The unobserved ephemeral region was determined to be the shortest-lived (2.5 hr) and lowest in magnetic flux density (13G) of the three regions. The Flat Crystal Spectrometer observed only low level signals in the O VIII 18.969 A line, which were not statistically significant to be positively identified with any of the 16 ephemeral regions detected in the photosphere. In addition, the data indicate that at any given time there lacked a one-to-one correspondence between observable bright points and photospheric ephemeral regions, while more ephemeral regions were observed than their counterparts in the transition region and the corona

  19. Developing a bright 17 keV x-ray source for probing high-energy-density states of matter at high spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Huntington, C. M.; Park, H.-S.; Maddox, B. R.; Barrios, M. A.; Benedetti, R.; Braun, D. G.; Landen, O. L.; Wehrenberg, C. E.; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, California, 94551 (United States); Hohenberger, M.; Regan, S. P. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2015-04-15

    A set of experiments were performed on the National Ignition Facility (NIF) to develop and optimize a bright, 17 keV x-ray backlighter probe using laser-irradiated Nb foils. High-resolution one-dimensional imaging was achieved using a 15 μm wide slit in a Ta substrate to aperture the Nb He{sub α} x-rays onto an open-aperture, time integrated camera. To optimize the x-ray source for imaging applications, the effect of laser pulse shape and spatial profile on the target was investigated. Two laser pulse shapes were used—a “prepulse” shape that included a 3 ns, low-intensity laser foot preceding the high-energy 2 ns square main laser drive, and a pulse without the laser foot. The laser spatial profile was varied by the use of continuous phase plates (CPPs) on a pair of shots compared to beams at best focus, without CPPs. A comprehensive set of common diagnostics allowed for a direct comparison of imaging resolution, total x-ray conversion efficiency, and x-ray spectrum between shots. The use of CPPs was seen to reduce the high-energy tail of the x-ray spectrum, whereas the laser pulse shape had little effect on the high-energy tail. The measured imaging resolution was comparably high for all combinations of laser parameters, but a higher x-ray flux was achieved without phase plates. This increased flux was the result of smaller laser spot sizes, which allowed us to arrange the laser focal spots from multiple beams and produce an x-ray source which was more localized behind the slit aperture. Our experiments are a first demonstration of point-projection geometry imaging at NIF at the energies (>10 keV) necessary for imaging denser, higher-Z targets than have previously been investigated.

  20. Increasing the Brightness of Light Sources

    OpenAIRE

    Fu, Ling

    2006-01-01

    In modern illumination systems, compact size and high brightness are important features. Light recycling allows an increase of the spectral radiance (brightness) emitted by a light source for the price of reducing the total radiant power. Light recycling means returning part of the emitted light to the source where part of it will escape absorption. As a result, the output brightness can be increased in a restricted phase space, ...

  1. High Energy Electron Detectors on Sphinx

    Science.gov (United States)

    Thompson, J. R.; Porte, A.; Zucchini, F.; Calamy, H.; Auriel, G.; Coleman, P. L.; Bayol, F.; Lalle, B.; Krishnan, M.; Wilson, K.

    2008-11-01

    Z-pinch plasma radiation sources are used to dose test objects with K-shell (˜1-4keV) x-rays. The implosion physics can produce high energy electrons (> 50keV), which could distort interpretation of the soft x-ray effects. We describe the design and implementation of a diagnostic suite to characterize the electron environment of Al wire and Ar gas puff z-pinches on Sphinx. The design used ITS calculations to model detector response to both soft x-rays and electrons and help set upper bounds to the spurious electron flux. Strategies to discriminate between the known soft x-ray emission and the suspected electron flux will be discussed. H.Calamy et al, ``Use of microsecond current prepulse for dramatic improvements of wire array Z-pinch implosion,'' Phys Plasmas 15, 012701 (2008) J.A.Halbleib et al, ``ITS: the integrated TIGER series of electron/photon transport codes-Version 3.0,'' IEEE Trans on Nuclear Sci, 39, 1025 (1992)

  2. High Performance Electronics on Flexible Silicon

    KAUST Repository

    Sevilla, Galo T.

    2016-09-01

    Over the last few years, flexible electronic systems have gained increased attention from researchers around the world because of their potential to create new applications such as flexible displays, flexible energy harvesters, artificial skin, and health monitoring systems that cannot be integrated with conventional wafer based complementary metal oxide semiconductor processes. Most of the current efforts to create flexible high performance devices are based on the use of organic semiconductors. However, inherent material\\'s limitations make them unsuitable for big data processing and high speed communications. The objective of my doctoral dissertation is to develop integration processes that allow the transformation of rigid high performance electronics into flexible ones while maintaining their performance and cost. In this work, two different techniques to transform inorganic complementary metal-oxide-semiconductor electronics into flexible ones have been developed using industry compatible processes. Furthermore, these techniques were used to realize flexible discrete devices and circuits which include metal-oxide-semiconductor field-effect-transistors, the first demonstration of flexible Fin-field-effect-transistors, and metal-oxide-semiconductors-based circuits. Finally, this thesis presents a new technique to package, integrate, and interconnect flexible high performance electronics using low cost additive manufacturing techniques such as 3D printing and inkjet printing. This thesis contains in depth studies on electrical, mechanical, and thermal properties of the fabricated devices.

  3. High energy electron irradiation of flowable materials

    International Nuclear Information System (INIS)

    Offermann, B.P.

    1975-01-01

    In order to efficiently irradiate a flowable material with high energy electrons, a hollow body is disposed in a container for the material and the material is caused to flow in the form of a thin layer across a surface of the body from or to the interior of the container while the material flowing across the body surface is irradiated. (U.S.)

  4. KEK/NAGOYA/SLAC: Highly polarized electrons

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In the push by the Japanese KEK Laboratory, in collaboration with university groups and overseas laboratories, to develop new techniques for the future Japan electronpositron collider (JLC), a recent achievement is a significant increase in the efficient yield of highly polarized electrons

  5. Decal Electronics: Printable Packaged with 3D Printing High-Performance Flexible CMOS Electronic Systems

    KAUST Repository

    Sevilla, Galo T.

    2016-10-14

    High-performance complementary metal oxide semiconductor electronics are flexed, packaged using 3D printing as decal electronics, and then printed in roll-to-roll fashion for highly manufacturable printed flexible high-performance electronic systems.

  6. Decal Electronics: Printable Packaged with 3D Printing High-Performance Flexible CMOS Electronic Systems

    KAUST Repository

    Sevilla, Galo T.; Cordero, Marlon D.; Nassar, Joanna M.; Hanna, Amir; Kutbee, Arwa T.; Carreno, Armando Arpys Arevalo; Hussain, Muhammad Mustafa

    2016-01-01

    High-performance complementary metal oxide semiconductor electronics are flexed, packaged using 3D printing as decal electronics, and then printed in roll-to-roll fashion for highly manufacturable printed flexible high-performance electronic systems.

  7. Burkina Faso - BRIGHT II

    Data.gov (United States)

    Millennium Challenge Corporation — Millennium Challenge Corporation hired Mathematica Policy Research to conduct an independent evaluation of the BRIGHT II program. The three main research questions...

  8. BrightFocus Foundation

    Science.gov (United States)

    ... About BrightFocus Foundation Featured Content BrightFocus: Investing in Science to Save Mind and Sight We're here to help. Explore ... recognition is very important. Monday, November 6, 2017 New Diagnosis? Managing a mind and sight disease is a journey. And you’ ...

  9. Proposal for Research on High-Brightness Cathodes for High-Power Free-Electron Lasers (FEL)

    Science.gov (United States)

    2013-05-09

    many failed double tips. Quad-tip emitters: If the KOH etching of the silicon mold is terminated prior to completion of the pyramid, then a small...process with 4" quartz tube furnace (Fig. 2.10). Optical microscope picture (left) and Raman spectrum (right). 5/9/2013 Vanderbilt University JTO...ONR/HEL/MRI Final Report 11 300-nm thick Si02 on silicon wafer. The Raman spectrum in Figure 2.11 clearly shows a 2700-cm" 1 peak and a 1590-cmŕ

  10. Time-resolved brightness measurements by streaking

    Science.gov (United States)

    Torrance, Joshua S.; Speirs, Rory W.; McCulloch, Andrew J.; Scholten, Robert E.

    2018-03-01

    Brightness is a key figure of merit for charged particle beams, and time-resolved brightness measurements can elucidate the processes involved in beam creation and manipulation. Here we report on a simple, robust, and widely applicable method for the measurement of beam brightness with temporal resolution by streaking one-dimensional pepperpots, and demonstrate the technique to characterize electron bunches produced from a cold-atom electron source. We demonstrate brightness measurements with 145 ps temporal resolution and a minimum resolvable emittance of 40 nm rad. This technique provides an efficient method of exploring source parameters and will prove useful for examining the efficacy of techniques to counter space-charge expansion, a critical hurdle to achieving single-shot imaging of atomic scale targets.

  11. Electronics, information, Communication and high technology

    International Nuclear Information System (INIS)

    1999-11-01

    The contents of this book are summary of investigation, investigation system, purpose of investigation, characteristic of this investigation, important studying and development filed, compare of the level of research and development, policy, characteristic of the respondent, a future illustration in 2025 cause of hindrance of realization, propel method of research and development, the prediction of the realization period the result of investigation in electronics, information communication and high technology.

  12. Physics of high intensity nanosecond electron source

    International Nuclear Information System (INIS)

    Herrera-Gomez, A.; Spicer, W.E.

    1993-08-01

    A new high-intensity, short-time electron source is now being used at the Stanford Linear Accelerator Center (SLAC). Using a GaAs negative affinity semiconductor in the construction of the cathode, it is possible to fulfill operation requirements such as peak currents of tens of amperes, peak widths of the order of nanoseconds, hundreds of hours of operation stability, and electron spin polarization. The cathode is illuminated with high intensity laser pulses, and photoemitted electrons constitute the yield. Because of the high currents, some nonlinear effects are present. Very noticeable is the so-called Charge Limit (CL) effect, which consists of a limit on the total charge in each pulse-that is, the total bunch charge stops increasing as the light pulse total energy increases. In this paper, we explain the mechanism of the CL and how it is caused by the photovoltaic effect. Our treatment is based on the Three-Step model of photoemission. We relate the CL to the characteristics of the surface and bulk of the semiconductor, such as doping, band bending, surface vacuum level, and density of surface states. We also discuss possible ways to prevent the Char's Level effect

  13. Highly integrated electronics for the star TPC

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, A.A.; Bieser, F.; Hearn, W.; Kleinfelder, S.; Merrick, T.; Millaud, J.; Noggle, T.; Rai, G.; Ritter, H.G.; Wieman, H. [Lawrence Berkeley Laboratory, CA (United States)

    1991-12-31

    The concept for the STAR TPC front-end electronics is presented and the progress toward the development of a fully integrated solution is described. It is the goal of the R+D program to develop the complete electronics chain for the STAR central TPC detector at RHIC. It is obvious that solutions chosen e.g. for ALEPH are not adequate for the 150000 channels that need to be instrumented for readout. It will be necessary to perform all the signal processing, digitization and multiplexing directly on the detector in order to reduce per channel cost and the amount of cabling necessary to read out the information. We follow the approach chosen by the EOS TPC project, where the readout electronics on the detector consists of an integrated preamplifier, a hybrid shaping amplifier, an integrated switched capacitor array and a highly multiplexed ADC. The STAR electronics will be further integrated so that approximately 16 channels of the preamplifier, the shaper, the analog store and the ADC will be contained in two integrated circuits located directly on the pad plane.

  14. Electron emission from nano-structured carbon composite materials and fabrication of high-quality electron emitters by using plasma technology

    International Nuclear Information System (INIS)

    Hiraki, H.; Hiraki, A.; Jiang, N.; Wang, H. X.

    2006-01-01

    Many trials have been done to fabricate high-quality electron-emitters from nano-composite carbon materials (such as nano-diamond, carbon nano tubes and others) by means of a variety of plasma chemical-vapor-deposition (CVD) techniques. Based upon the mechanism of electron emission, we have proposed several strategic guide lines for the fabrication of good emitters. Then, following these lines, several types of emitters were tried. One of the emitters has shown a worldclass, top ranking for fabricating very bright lamps: namely, a low turn-on voltage (0.5 ∼ 1 V/μm to induce 10 μA/cm 2 emission current) to emit a 1 mA/cm 2 current at 3 V/μm and 100 mA/cm 2 current at a slightly higher applied voltage. The bright lamps are Mercury-free fluorescence lamps to exhibit brightness of ∼10 5 cd/m 2 with high efficiency of ∼100 lm/w.

  15. High-resolution electron microscope image analysis approach for superconductor YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    Xu, J.; Lu, F.; Jia, C.; Hua, Z.

    1991-01-01

    In this paper, an HREM (High-resolution electron microscope) image analysis approach has been developed. The image filtering, segmentation and particles extraction based on gray-scale mathematical morphological operations, are performed on the original HREM image. The final image is a pseudocolor image, with the background removed, relatively uniform brightness, filtered slanting elongation, regular shape for every kind of particle, and particle boundaries that no longer touch each other so that the superconducting material structure can be shown clearly

  16. Development of a high average current polarized electron source with long cathode operational lifetime

    Directory of Open Access Journals (Sweden)

    C. K. Sinclair

    2007-02-01

    Full Text Available Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2×10^{5}   C/cm^{2} and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  17. Extremely high frequency RF effects on electronics.

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  18. High-intensity-laser-electron scattering

    International Nuclear Information System (INIS)

    Meyerhofer, D.D.

    1997-01-01

    In the field of an intense laser, photon-electron scattering becomes nonlinear when the oscillatory energy of the electron approaches its rest mass. The electron wave function is dressed by the field with a concomitant increase in the effective electron mass. When the photon energy in the electron rest frame is comparable to the electron rest mass, multiphoton Compton scattering occurs. When the photon energy is significantly lower than the electron rest mass, the electron acquires momentum from the photon field and emits harmonics. This paper reviews nonlinear photon-electron scattering processes and results from two recent experiments where they have been observed

  19. The surface brightness of spiral galaxies: Pt. 4

    International Nuclear Information System (INIS)

    Phillipps, S.; Disney, M.; Ohio State Univ., Columbus

    1988-01-01

    Using measurements from IRAS correlations are found between optical surface brightness and both infrared-to-optical flux ratio and infrared colour temperature, in the sense that galaxies with high surface brightness have higher FIR emission and higher temperatures. (author)

  20. Stunningly bright optical emission

    Science.gov (United States)

    Heinke, Craig O.

    2017-12-01

    The detection of bright, rapid optical pulsations from pulsar PSR J1023+0038 have provided a surprise for researchers working on neutron stars. This discovery poses more questions than it answers and will spur on future work and instrumentation.

  1. Electronic coupling between photo-excited stacked bases in DNA and RNA strands with emphasis on the bright states initially populated

    DEFF Research Database (Denmark)

    Nielsen (Baggesen), Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

    2013-01-01

    . In this review paper, we focus on the bright states initially populated and discuss their nature based on information obtained from systematic absorption and circular dichroism experiments on single strands of different lengths. Our results from the last five years are compared with those from other groups......, and are discussed in the context of successive deexcitation schemes. Pieces to the puzzle have come from different experiments and theory but a complete description has yet to emerge. As such the story about DNA/RNA photophysical decay mechanisms resembles the tale about the blind men and the elephant where all see...

  2. Electronics for very high rate tracking detectors

    International Nuclear Information System (INIS)

    Williams, H.H.; Dressnandt, N.; Ekenberg, T.; Gerds, E.J.; Newcomer, F.M.; Tedja, S.; Van Berg, R.; Van der Speigel, J.

    1995-01-01

    Results are presented on a system of electronics designed for very high rate tracking detectors at the SSC and LHC. The primary goal was a system for signal detection, time measurement, and readout for the straw tracker for SDC. An integrated circuit incorporating eight channels of amplifier-shaper-discriminator (including detector tail cancellation), and two different integrated circuits for time measurement are described. The performance of tracking measurements up to counting rates of 8 MHz per wire is reported, as well as preliminary results from a baseline restoration circuit. (orig.)

  3. Technical report of electronics shop characteristics of high speed electronics component, (1)

    International Nuclear Information System (INIS)

    Watanabe, Shin-ichi; Shiino, Kazuo.

    1975-01-01

    We must develop electronics circuits for high speed signals. The electronics components of the circuits make use of the special components. This report treats a pulse response of the electronics components (i.e. coaxial cable, connector, resistor, capacitor, diode, transistor) for high speed electronics. The results of this report was already applied constructions of high speed electronics circuits and experimental equipments of the High Energy Physics Division. (auth.)

  4. Damage structure of gallium arsenide irradiated in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Loretto, D.; Loretto, M.H.

    1989-01-01

    Semi-insulating undoped gallium arsenide has been irradiated in a high-voltage electron microscope between room temperature and about 500 0 C for doses of up to 5 x 10 22 electrons cm -2 at 1 MeV. Room-temperature irradiation produces small (less than 5 nm) damage clusters. As the temperature of the irradiation is increased, the size of these clusters increases, until at about 300 0 C a high density of dislocation loops can be resolved. The dislocation loops, 20 nm or less in diameter, which are produced at about 500 0 C have been analysed in a bright field using a two-beam inside-outside method which minimises the tilt necessary between micrographs. It is concluded that the loops are an interstitial perfect-edge type with a Burgers vector of (a/2) . (author)

  5. Do Low Surface Brightness Galaxies Host Stellar Bars?

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes Sodi, Bernardo; Sánchez García, Osbaldo, E-mail: b.cervantes@irya.unam.mx, E-mail: o.sanchez@irya.unam.mx [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Campus Morelia, A.P. 3-72, C.P. 58089 Michoacán, México (Mexico)

    2017-09-20

    With the aim of assessing if low surface brightness galaxies host stellar bars and by studying the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 data set to construct a large volume-limited sample of galaxies and then segregate these galaxies as having low or high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than that found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mostly driven by a correlation of the surface brightness with the spin and the gas richness of the galaxies, showing only a minor dependence on the surface brightness. We also find that the length of the bars is strongly dependent on the surface brightness, and although some of this dependence is attributed to the gas content, even at a fixed gas-to-stellar mass ratio, high surface brightness galaxies host longer bars than their low surface brightness counterparts, which we attribute to an anticorrelation of the surface brightness with the spin.

  6. Do Low Surface Brightness Galaxies Host Stellar Bars?

    International Nuclear Information System (INIS)

    Cervantes Sodi, Bernardo; Sánchez García, Osbaldo

    2017-01-01

    With the aim of assessing if low surface brightness galaxies host stellar bars and by studying the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 data set to construct a large volume-limited sample of galaxies and then segregate these galaxies as having low or high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than that found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mostly driven by a correlation of the surface brightness with the spin and the gas richness of the galaxies, showing only a minor dependence on the surface brightness. We also find that the length of the bars is strongly dependent on the surface brightness, and although some of this dependence is attributed to the gas content, even at a fixed gas-to-stellar mass ratio, high surface brightness galaxies host longer bars than their low surface brightness counterparts, which we attribute to an anticorrelation of the surface brightness with the spin.

  7. Shielding for high energy, high intensity electron accelerator installation

    International Nuclear Information System (INIS)

    Warawas, C.; Chongkum, S.

    1997-03-01

    The utilization of electron accelerators (eBA) is gradually increased in Thailand. For instance, a 30-40 MeV eBA are used for tumor and cancer therapy in the hospitals, and a high current eBA in for gemstone colonization. In the near future, an application of eBA in industries will be grown up in a few directions, e.g., flue gases treatment from the coal fire-power plants, plastic processing, rubber vulcanization and food preservation. It is the major roles of Office of Atomic Energy for Peace (OAEP) to promote the peaceful uses of nuclear energy and to regulate the public safety and protection of the environment. By taking into account of radiation safety aspect, high energy electrons are not only harmful to human bodies, but the radioactive nuclides can be occurred. This report presents a literature review by following the National Committee on Radiation Protection and Measurements (NCRP) report No.31. This reviews for parametric calculation and shielding design of the high energy (up to 100 MeV), high intensity electron accelerator installation

  8. Suppressed speckle contrast of blue light emission out of white lamp with phosphors excited by blue laser diodes for high-brightness lighting applications

    Science.gov (United States)

    Kinoshita, Junichi; Ikeda, Yoshihisa; Takeda, Yuji; Ueno, Misaki; Kawasaki, Yoji; Matsuba, Yoshiaki; Heike, Atsushi

    2012-11-01

    The speckle contrast of blue light emission out of high-brightness white lamps using phosphors excited by InGaN/GaN blue laser diodes is evaluated as a measure of coherence. As a result, speckle contrast of as low as 1.7%, the same level as a blue light emitting diode, is obtained. This implies that the original blue laser light can be converted into incoherent light through lamp structures without any dynamic mechanisms. This unique speckle-free performance is considered to be realized by multiple scattering inside the lamp structure, the multi-longitudinal mode operation of the blue laser diodes, and the use of multiple laser diodes. Such almost-incoherent white lamps can be applied for general lighting without any nuisance of speckle noise and should be categorized as lamps rather than lasers in terms of laser safety regulation.

  9. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao

    2016-05-25

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  10. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao; Ng, Tien Khee; Leonard, John T.; Pourhashemi, Arash; Nakamura, Shuji; DenBaars, Steven P.; Speck, James S.; Alyamani, Ahmed Y.; El-desouki, Munir M.; Ooi, Boon S.

    2016-01-01

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  11. Electron Linacs for High Energy Physics

    International Nuclear Information System (INIS)

    Wilson, Perry B.

    2011-01-01

    The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

  12. Fabrication of high-brightness GaN-based light-emitting diodes via thermal nanoimprinting of ZnO-nanoparticle-dispersed resin

    International Nuclear Information System (INIS)

    Byeon, Kyeong-Jae; Cho, Joong-Yeon; Jo, Han-Byeol; Lee, Heon

    2015-01-01

    Highlights: • A various high-refractive-index ZnO patterns were formed on LED using imprinting. • Mechanism of light extraction enhancement was demonstrated by simulation and EL. • Light output power of patterned LED was improved up 19.6% by light waveguide effect. - Abstract: We fabricated high-brightness GaN-based light-emitting diodes (LEDs) with highly refractive patterned structures by using a thermal nanoimprint lithography (NIL). A highly refractive ZnO-nanoparticle-dispersed resin (ZNDR) was used in NIL, and a submicron hole, a submicron high-aspect-ratio pillar, and microconvex arrays were fabricated on the indium tin oxide (ITO) top electrode of GaN-based LED devices. We analyzed the light extraction mechanism for each of the three types of patterns by using a finite element method simulation, and found that the high-aspect-ratio pillar had a great ability to improve light extraction owing to its waveguide effect and prominent scattering effect. As a result, the light output power, which was measured in an integrating sphere, of the LED device was enhanced by up to 19.6% when the high-aspect-ratio pillar array was formed on the top ITO electrode of the device. Further, the electrical properties of none of the patterned LED devices fabricated using ZNDR degraded in comparison to those of bare LED devices

  13. STANFORD: Highly polarized SLC electron beams

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Full text: Using specialized photocathodes made with 'strained' gallium arsenide, physicists at the Stanford Linear Accelerator Center (SLAC) have generated electron beams with polarizations in excess of 60 percent a year ahead of schedule. Together with recent luminosity increases, this breakthrough will have a major impact on the physics output of the Stanford Linear Collider (SLC). Beam polarization was almost tripled using photocathodes in which a gallium arsenide layer was grown epitaxially over a substrate of gallium arsenide phosphide. The mismatch between these two layers deforms the crystal structure and removes a degeneracy in the valence band structure, permitting selective optical pumping of one unique spin state. Whereas conventional gallium arsenide photocathodes are limited to 50 percent polarization because of this degeneracy (and realistic cathodes fall substantially below this theoretical limit), such strained crystal lattices have the potential to yield polarizations close to 100 percent. Polarization enhancement with strained lattices was first demonstrated in 1991 by a SLAC/Wisconsin/ Berkeley group (May 1991, page 6) with a 71 percent polarization in a laboratory experiment. More recently this group has achieved polarization in excess of 90 percent, reported last November at the Nagoya Spin Symposium. (In a complementary development, a Japanese KEK/ Nagoya/KEK obtains polarized beams using a 'superlattice' - May 1991, page 4.) The 1993 SLC run, the strained gallium arsenide photocathode technique's debut in an operating particle accelerator, has proved to be a resounding, unqualified success - as have physics experiments on the Z particles produced by the highly polarized beam. A conservative approach was called for, due to concerns about possible charge saturation effects. A relatively thick (0.3 micron) gallium arsenide layer was used for the photocathode in the SLC polarized electron source. With a titanium

  14. Sanitation methods using high energy electron beams

    International Nuclear Information System (INIS)

    Levaillant, C.; Gallien, C.L.

    1979-01-01

    Short recycling of waste water and the use of liquid or dehydrated sludge as natural manure for agriculture or animal supplement feed is of great economical and ecological interest. It implies strong biological and chemical disinfection. Ionizing radiations produced by radioactive elements or linear accelerators can be used as a complement of conventional methods in the treatment of liquid and solid waste. An experiment conducted with high-energy electron-beam linear accelerators is presented. Degradation of undesirable metabolites in water occurs for a dose of 50 kRad. Undesirable seeds present in sludge are destroyed with a 200 kRad dose. A 300 kRad dose is sufficient for parasitic and bacterial disinfection (DL 90). Destruction of polio virus (DL 90) is obtained for 400 kRad. Higher doses (1000 to 2000 kRad) produce mineralization of toxic organic mercury, reduce some chemical toxic pollutants present in sludge and improve flocculation. (author)

  15. Improved methods for high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.R.

    1987-04-01

    Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

  16. High frequency free-electron laser results

    International Nuclear Information System (INIS)

    Boyer, K.; Brau, C.A.; Newman, B.E.; Stein, W.E.; Warren, R.W.; Winston, J.G.; Young, L.M.

    1983-01-01

    By looking at the free-electron laser as a particle accelerator working backwards, Morton realized that the techniques used to accelerate particles could be used to improve the performance of free-electron lasers. In particular, he predicted the capture of electrons in ''stable-phase'' regions, or ''buckets'' in the electron phase space, and proposed that by decelerating the buckets, the trapped electrons could be decelerated to extract significant amounts of their energy as optical radiation. In fact, since electrons not trapped in the stable regions are forever excluded from them--at least in the adiabatic approximation--displacement techniques could also be used to accelerate or decelerate electrons in a free-electron laser. This paper explains the principle behind ''phase-displacement'' acceleration and details an experiment carried out with a 20-MeV electron beam to test these predictions. Results obtained with a tapered-wiggler free-electron laser demonstrate the concepts proposed by Morton for enhanced efficiency. They show deceleration of electrons by as much as 7% and extraction of more than 3% of the total electron-beam energy as laser energy when the laser is operated as an amplifier. The experiment is presently being reconfigured to examine its performance as a laser oscillator

  17. Giant Low Surface Brightness Galaxies

    Science.gov (United States)

    Mishra, Alka; Kantharia, Nimisha G.; Das, Mousumi

    2018-04-01

    In this paper, we present radio observations of the giant low surface brightness (LSB) galaxies made using the Giant Metrewave Radio Telescope (GMRT). LSB galaxies are generally large, dark matter dominated spirals that have low star formation efficiencies and large HI gas disks. Their properties suggest that they are less evolved compared to high surface brightness galaxies. We present GMRT emission maps of LSB galaxies with an optically-identified active nucleus. Using our radio data and archival near-infrared (2MASS) and near-ultraviolet (GALEX) data, we studied morphology and star formation efficiencies in these galaxies. All the galaxies show radio continuum emission mostly associated with the centre of the galaxy.

  18. Micro-structure Engineering of InGaN/GaN Quantum Wells for High Brightness Light Emitting Devices

    KAUST Repository

    Shen, Chao

    2013-01-01

    diameter (D) micro-LED-pillar was achieved, compared to that of a 200 μm diameter LED (20 A/cm2), both at 10 V bias voltage. In addition, an increase in sustained quantum efficiency from 70.2% to 83.7% at high injection current density (200 A/cm2

  19. Zeolites - a high resolution electron microscopy study

    International Nuclear Information System (INIS)

    Alfredsson, V.

    1994-10-01

    High resolution transmission electron microscopy (HRTEM) has been used to investigate a number of zeolites (EMT, FAU, LTL, MFI and MOR) and a member of the mesoporous M41S family. The electron optical artefact, manifested as a dark spot in the projected centre of the large zeolite channels, caused by insufficient transfer of certain reflections in the objective lens has been explained. The artefact severely hinders observation of materials confined in the zeolite channels and cavities. It is shown how to circumvent the artefact problem and how to image confined materials in spite of disturbance caused by the artefact. Image processing by means of a Wiener filter has been applied for removal of the artefact. The detailed surface structure of FAU has been investigated. Comparison of experimental micrographs with images simulated using different surface models indicates that the surface can be terminated in different ways depending on synthesis methods. The dealuminated form of FAU (USY) is covered by an amorphous region. Platinum incorporated in FAU has a preponderance to aggregate in the (111) twin planes, probably due to a local difference in cage structure with more spacious cages. It is shown that platinum is intra-zeolitic as opposed to being located on the external surface of the zeolite crystal. This could be deduced from tomography of ultra-thin sections among observations. HRTEM studies of the mesoporous MCM-41 show that the pores have a hexagonal shape and also supports the mechanistic model proposed which involves a cooperative formation of a mesophase including the silicate species as well as the surfactant. 66 refs, 24 figs

  20. Theoretical description of high-lying two-electrons states

    International Nuclear Information System (INIS)

    Greene, C.H.; Cavagnero, M.; Sadeghpour, H.R.

    1993-01-01

    Within the past two years, experiments on high-lying doubly-excited states in He and H- have shown spectra at energies near excited hydrogenic thresholds having principal quantum numbers in the range N=5--9. While they display some nontrivial complexities, the spectra are tremendously simpler than might be anticipated on the basis of independent electron models, in that only a small fraction of the total number of anticipated resonances are observed experimentally. Moreover, for principal quantum number N that are not too high, specifically N - , the resonance positions are described accurately by adiabatic calculations using hyperspherical coordinates and can be parametrized by a remarkably simple two-electron Rydberg formula. The observed propensity for excitation of only a small subset of the possible resonance states has been codified by several groups into approximate selection rules based on alternative (but apparently equivalent) classification schemes. Comparatively few attempts have been made at quantitative tests of the validity of these rules. The present review describes recent efforts to quantify their accuracy and limitations using R-matrix and quantum defect techniques, and Smith's delay-time matrix. Prospensity rules for exciting different degrees of freedom are found to differ greatly in their degree of validity

  1. High quality electron beams from a plasma channel guided laser wakefield accelerator

    International Nuclear Information System (INIS)

    Geddes, C.G.R.; Toth, Cs.; Tilborg, J. van; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Nieter, C.; Cary, J.; Leemans, W.P.

    2004-01-01

    Laser driven accelerators, in which particles are accelerated by the electric field of a plasma wave driven by an intense laser, have demonstrated accelerating electric fields of hundreds of GV/m. These fields are thousands of times those achievable in conventional radiofrequency (RF) accelerators, spurring interest in laser accelerators as compact next generation sources of energetic electrons and radiation. To date however, acceleration distances have been severely limited by lack of a controllable method for extending the propagation distance of the focused laser pulse. The ensuing short acceleration distance results in low energy beams with 100% electron energy spread, limiting applications. Here we demonstrate that a relativistically intense laser can be guided by a preformed plasma density channel and that the longer propagation distance can result in electron beams of percent energy spread with low emittance and increased energy, containing >10 9 electrons above 80 MeV. The preformed plasma channel technique forms the basis of a new class of accelerators, combining beam quality comparable to RF accelerators with the high gradients of laser accelerators to produce compact tunable high brightness electron and radiation sources

  2. Electron-electron interactions in graphene field-induced quantum dots in a high magnetic field

    DEFF Research Database (Denmark)

    Orlof, A.; Shylau, Artsem; Zozoulenko, I. V.

    2015-01-01

    We study the effect of electron-electron interaction in graphene quantum dots defined by an external electrostatic potential and a high magnetic field. To account for the electron-electron interaction, we use the Thomas-Fermi approximation and find that electron screening causes the formation...... of compressible strips in the potential profile and the electron density. We numerically solve the Dirac equations describing the electron dynamics in quantum dots, and we demonstrate that compressible strips lead to the appearance of plateaus in the electron energies as a function of the magnetic field. Finally...

  3. Ultra-High Density Electron Beams for Beam Radiation and Beam Plasma Interaction

    CERN Document Server

    Anderson, Scott; Frigola, Pedro; Gibson, David J; Hartemann, Fred V; Jacob, Jeremy S; Lim, Jae; Musumeci, Pietro; Rosenzweig, James E; Travish, Gil; Tremaine, Aaron M

    2005-01-01

    Current and future applications of high brightness electron beams, which include advanced accelerators such as the plasma wake-field accelerator (PWFA) and beam-radiation interactions such as inverse-Compton scattering (ICS), require both transverse and longitudinal beam sizes on the order of tens of microns. Ultra-high density beams may be produced at moderate energy (50 MeV) by compression and subsequent strong focusing of low emittance, photoinjector sources. We describe the implementation of this method used at LLNL's PLEIADES ICS x-ray source in which the photoinjector-generated beam has been compressed to 300 fsec duration using the velocity bunching technique and focused to 20 μm rms size using an extremely high gradient, permanent magnet quadrupole (PMQ) focusing system.

  4. Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Peng Dengfeng [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Wang Xusheng; Yao Xi [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xu Chaonan [National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Lin Jian; Sun Tiantuo [College of Material Science and Engineering, Tongji University, 4800 Cao' an Highway, Shanghai 201804 (China)

    2012-05-15

    Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  5. ELEC-2005: Electronics in High Energy Physics

    CERN Multimedia

    Monique Duval

    2004-01-01

    ELEC-2005 is a new course series on modern electronics, given by CERN physicists and engineers in the format of the successful ELEC-2002 course series, and within the framework of the 2005 Technical Training Programme. This comprehensive course series is designed for people who are not electronics specialists, for example physicists, engineers and technicians working at or visiting the laboratory, who use or will use electronics in their present or future activities, in particular in the context of the LHC accelerator and experiments. ELEC-2005 will composed of four Terms throughout the year: Winter Term: Introduction to electronics in HEP (January-February, 6 lectures) Spring Term: Integrated circuits and VLSI technology for physics (March, 6 lectures) Summer Term: System electronics for physics: Issues (May, 7 lectures) Winter Term: Electronics applications in HEP experiments (November-December, 10 lectures) Lectures within each Term will take place on Tuesdays and Thursdays, from 10:00 to 12:30. The...

  6. A summary of high-temperature electronics research and development

    International Nuclear Information System (INIS)

    Thome, F.V.; King, D.B.

    1991-01-01

    Current and future needs in automative, aircraft, space, military, and well logging industries require operation of electronics at higher temperatures than today's accepted limit of 395 K. Without the availability of high-temperature electronics, many systems must operate under derated conditions or must accept severe mass penalties required by coolant systems to maintain electronic temperatures below critical levels. This paper presents ongoing research and development in the electronics community to bring high-temperature electronics to commercial realization. Much of this work was recently reviewed at the First International High-Temperature Electronics Conference held 16--20 June 1991 in Albuquerque, New Mexico. 4 refs., 1 tab

  7. Ultrathin Two-Dimensional Organic-Inorganic Hybrid Perovskite Nanosheets with Bright, Tunable Photoluminescence and High Stability.

    Science.gov (United States)

    Yang, Shuang; Niu, Wenxin; Wang, An-Liang; Fan, Zhanxi; Chen, Bo; Tan, Chaoliang; Lu, Qipeng; Zhang, Hua

    2017-04-03

    Two-dimensional (2D) organic-inorganic hybrid perovskite nanosheets (NSs) are attracting increasing research interest due to their unique properties and promising applications. Here, for the first time, we report the facile synthesis of single- and few-layer free-standing phenylethylammonium lead halide perovskite NSs, that is, (PEA) 2 PbX 4 (PEA=C 8 H 9 NH 3 , X=Cl, Br, I). Importantly, their lateral size can be tuned by changing solvents. Moreover, these ultrathin 2D perovskite NSs exhibit highly efficient and tunable photoluminescence, as well as superior stability. Our study provides a simple and general method for the controlled synthesis of 2D perovskite NSs, which may offer a new avenue for their fundamental studies and optoelectronic applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Bright is the New Black - Multi-Year Performance of Generic High-Albedo Roofs in an Urban Climate

    Science.gov (United States)

    Gaffin, S. R.; Imhoff, M.; Rosenzweig, C.; Khanbilvardi, R.; Pasqualini, A.; Kong, A. Y. Y.; Grillo, D.; Freed, A.; Hillel, D.; Hartung, E.

    2012-01-01

    High-albedo white and cool roofing membranes are recognized as a fundamental strategy that dense urban areas can deploy on a large scale, at low cost, to mitigate the urban heat island effect. We are monitoring three generic white membranes within New York City that represent a cross-section of the dominant white membrane options for U.S. flat roofs: (1) an ethylene propylene diene monomer (EPDM) rubber membrane; (2) a thermoplastic polyolefin (TPO) membrane and; (3) an asphaltic multi-ply built-up membrane coated with white elastomeric acrylic paint. The paint product is being used by New York City s government for the first major urban albedo enhancement program in its history. We report on the temperature and related albedo performance of these three membranes at three different sites over a multi-year period. The results indicate that the professionally installed white membranes are maintaining their temperature control effectively and are meeting the Energy Star Cool Roofing performance standards requiring a three-year aged albedo above 0.50. The EPDM membrane however shows evidence of low emissivity. The painted asphaltic surface shows high emissivity but lost about half of its initial albedo within two years after installation. Given that the acrylic approach is an important "do-it-yourself," low-cost, retrofit technique, and, as such, offers the most rapid technique for increasing urban albedo, further product performance research is recommended to identify conditions that optimize its long-term albedo control. Even so, its current multi-year performance still represents a significant albedo enhancement for urban heat island mitigation.

  9. Measuring brightness temperature distributions of plasma bunches

    International Nuclear Information System (INIS)

    Kirko, V.I.; Stadnichenko, I.A.

    1981-01-01

    The possibility of restoration of brightness temperature distribution along plasma jet on the base of a simple ultra high- speed photography and subsequent photometric treatment is shown. The developed technique has been applied for finding spectral radiation intensity and brightness temperature of plasma jets of a tubular gas-cumulative charge and explosive plasma compressor. The problem of shock wave front has been successfully solved and thus distribution of above parameters beginning from the region preceeding the shock wave has been obtained [ru

  10. Electronic phase separation and high temperature superconductors

    International Nuclear Information System (INIS)

    Kivelson, S.A.

    1994-01-01

    The authors review the extensive evidence from model calculations that neutral holes in an antiferromagnet separate into hole-rich and hole-poor phases. All known solvable limits of models of holes in a Heisenberg antiferromagnet exhibit this behavior. The authors show that when the phase separation is frustrated by the introduction of long-range Coulomb interactions, the typical consequence is either a modulated (charge density wave) state or a superconducting phase. The authors then review some of the strong experimental evidence supporting an electronically-driven phase separation of the holes in the cuprate superconductors and the related Ni oxides. Finally, the authors argue that frustrated phase separation in these materials can account for many of the anomalous normal state properties of the high temperature superconductors and provide the mechanism of superconductivity. In particular, it is shown that the T-linear resistivity of the normal state is a paraconductivity associated with a novel composite pairing, although the ordered superconducting state is more conventional

  11. Electronic properties of high Tc superconductors

    International Nuclear Information System (INIS)

    Rojo, A.G.

    1989-01-01

    Using analytical and numerical methods, the electronic properties of the copper-oxygen plane in the normal phase of high Tc superconductors are described. Using the slave-boson technique in the saddle point, a theory of the metal insulator transition which generalizes the notions of a Mott insulator to the case of more than a single band for those planes is presented. A phase-diagram is obtained in the parameter space and effective masses, optical gaps and metallization are calculated as a function of the number of carriers. Based on the experimental evidence, the theory permits classification of superconducting compounds as charge transfer insulators in the stoichiometric case. The insulator state is characterized by a non-zero optical gap and a divergent effective mass which corresponds to the breakage of a Fermi-liquid scheme. The results obtained are applicable to metal-transition-oxides whose behaviour has been traditionally controversial and it is concluded that it is necessary to broaden the meaning of a Mott insulator to the case of more than a single band to better understand them. Based on the ideas of group renormalization in a real space, a lattice approximation is presented, which allows: a) To complement the treatment of slave-bosons in phase diagrams and optical gaps; b) Identification of an attraction mechanism between carriers originating from purely repulsive interactions. Numerical calculations in small clusters show the existence of a pairing mechanism showing a superconducting instability from a charge transfer insulator. (Author) [es

  12. A cold atom electron source

    NARCIS (Netherlands)

    Taban, G.

    2009-01-01

    Pulsed bright electron sources offer the possibility to study the structure of matter in great spatial and temporal detail. An example of an indirect method is to generate hard X-ray °ashes with high brilliance, a new Free Electron Laser facility is under construction. It requires an electron source

  13. The First Non-Dispersive High-Resolution Spectroscopy of an X-ray-bright Galaxy Cluster

    Science.gov (United States)

    Yamaguchi, Hiroya; Hitomi Collaboration

    2018-06-01

    The Hitomi X-ray Observatory was equipped with the Soft X-ray Spectrometer (SXS), an X-ray microcalorimeter that achieved an energy resolution of 5 eV (@0.5-10 keV) for extended objects. This offered an unprecedented benchmark of atomic modeling and database for hot collisional plasmas, revealing both successes and challenges in the current atomic codes that are widely used by the X-ray astronomy community. I will review the Hitomi observations of the brightest part of the Perseus Cluster, whose X-ray spectrum is dominated by thermal emission from the intra-cluster medium (ICM). The SXS successfully measured the turbulent velocities and metal abundances of the ICM, which radically altered our understanding of the dynamics and chemical enrichment in this object. At the same time, the high-resolution X-ray data led to significant improvement in the atomic models, such as AtomDB and SPEX -- I will briefly overview how this improvement was made. Nevertheless, there are still significant discrepancies among the public atomic models, causing systematic uncertainties in measurements of the temperature, abundance, and degree of the resonance scattering. Requirements for future improvements will be summarized in this context.

  14. Design studies of an electrostatic quadrupole channel for transport of a high-brightness H- beam and comparison with gas focusing

    International Nuclear Information System (INIS)

    Chang, C.R.; Horowitz, E.; Reiser, M.

    1989-01-01

    Transport of low-energy, high-brightness H - beams from the ion source to the radio-frequency quadrupole (RFQ) accelerator requires the solution of several physics and engineering problems to avoid particle losses and emittance growth. The authors developed a conceptual design of an electrostatic quadrupole channel for transport of a 120 keV, 120 mA, H - beam into a 425 MHz RFQ with low emittance growth and high transmission efficiency. This design satisfies several constraints imposed by voltage breakdown and beam optics considerations. The system will consist entirely of electrostatic lenses which prevent plasma build-up and eliminate possible emittance growth from plasma fluctuations. Pertinent design features a worst case non-linear analysis for the electrostatic quadrupole channel, and first results of a particle simulation code used to study beam loss and emittance growth are reported. As an alternative to the electrostatic quadrupole concept, gas focusing is being investigated for transporting low-energy H - beams. Recent results from the numerical simulations of such a gas focussing channel are presented

  15. Electron clouds in high energy hadron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, Fedor

    2013-08-29

    The formation of electron clouds in accelerators operating with positrons and positively charge ions is a well-known problem. Depending on the parameters of the beam the electron cloud manifests itself differently. In this thesis the electron cloud phenomenon is studied for the CERN Super Proton Synchrotron (SPS) and Large Hadron Collider (LHC) conditions, and for the heavy-ion synchrotron SIS-100 as a part of the FAIR complex in Darmstadt, Germany. Under the FAIR conditions the extensive use of slow extraction will be made. After the acceleration the beam will be debunched and continuously extracted to the experimental area. During this process, residual gas electrons can accumulate in the electric field of the beam. If this accumulation is not prevented, then at some point the beam can become unstable. Under the SPS and LHC conditions the beam is always bunched. The accumulation of electron cloud happens due to secondary electron emission. At the time when this thesis was being written the electron cloud was known to limit the maximum intensity of the two machines. During the operation with 25 ns bunch spacing, the electron cloud was causing significant beam quality deterioration. At moderate intensities below the instability threshold the electron cloud was responsible for the bunch energy loss. In the framework of this thesis it was found that the instability thresholds of the coasting beams with similar space charge tune shifts, emittances and energies are identical. First of their kind simulations of the effect of Coulomb collisions on electron cloud density in coasting beams were performed. It was found that for any hadron coasting beam one can choose vacuum conditions that will limit the accumulation of the electron cloud below the instability threshold. We call such conditions the ''good'' vacuum regime. In application to SIS-100 the design pressure 10{sup -12} mbar corresponds to the good vacuum regime. The transition to the bad vacuum

  16. The brightness of colour.

    Directory of Open Access Journals (Sweden)

    David Corney

    Full Text Available The perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour appear brighter than stimuli that are less saturated at the same luminance. Similarly, stimuli that are red or blue appear brighter than equiluminant yellow and green stimuli. This non-linear relationship between stimulus intensity and brightness, called the Helmholtz-Kohlrausch (HK effect, was first described in the nineteenth century but has never been explained. Here, we take advantage of the relative simplicity of this 'illusion' to explain it and contextual effects more generally, by using a simple Bayesian ideal observer model of the human visual ecology. We also use fMRI brain scans to identify the neural correlates of brightness without changing the spatial context of the stimulus, which has complicated the interpretation of related fMRI studies.Rather than modelling human vision directly, we use a Bayesian ideal observer to model human visual ecology. We show that the HK effect is a result of encoding the non-linear statistical relationship between retinal images and natural scenes that would have been experienced by the human visual system in the past. We further show that the complexity of this relationship is due to the response functions of the cone photoreceptors, which themselves are thought to represent an efficient solution to encoding the statistics of images. Finally, we show that the locus of the response to the relationship between images and scenes lies in the primary visual cortex (V1, if not earlier in the visual system, since the brightness of colours (as opposed to their luminance accords with activity in V1 as measured with fMRI.The data suggest that perceptions of brightness represent a robust

  17. High performance flexible electronics for biomedical devices.

    Science.gov (United States)

    Salvatore, Giovanni A; Munzenrieder, Niko; Zysset, Christoph; Kinkeldei, Thomas; Petti, Luisa; Troster, Gerhard

    2014-01-01

    Plastic electronics is soft, deformable and lightweight and it is suitable for the realization of devices which can form an intimate interface with the body, be implanted or integrated into textile for wearable and biomedical applications. Here, we present flexible electronics based on amorphous oxide semiconductors (a-IGZO) whose performance can achieve MHz frequency even when bent around hair. We developed an assembly technique to integrate complex electronic functionalities into textile while preserving the softness of the garment. All this and further developments can open up new opportunities in health monitoring, biotechnology and telemedicine.

  18. Electronic behavior of highly correlated metals

    International Nuclear Information System (INIS)

    Reich, A.

    1988-10-01

    This thesis addresses the question of the strongly interacting many-body problem: that is, systems where the interparticle correlations are so strong as to defy perturbative approaches. These subtle correlations occur in narrow band materials, such as the lanthanides and actinides, wherein the f-electrons are so localized that a variety of new phenomena, including intermediate-valence and heavy-fermionic behavior, may occur. As well, one has the alloying problem, where local interactions are paramount in determining the overall behavior. The technique employed in dealing with these systems is the Small Cluster method, wherein the full many-body Hamiltonian for a small grouping of atoms, coupled with periodic boundary conditions, is solved exactly. This is tantamount to solving a bulk crystal at the high points of symmetry in the Brillouin Zone. The mathematical overhead is further reduced by employing the full space group and spin symmetries. By its very nature, the Small Cluster method is well able to handle short-range interactions, as well as the combinatorial complexity of the many-body problem, on an equal footing. The nature of long-range order and phase transition behavior cannot be incorporated, but sometimes clues as to their origin can be discerned. The calculations presented include: a two-band Anderson model for an intermediate-valence system, wherein photoemission and fluctuation behavior is examined; a single-band Hubbard model for a ternary alloy system, such as copper-silver-gold; and a Hubbard model for a heavy- fermion system, wherein Fermi surface, transport, magnetic and superconducting properties are discussed. 148 refs., 31 figs., 24 tabs

  19. Application of high power microwave vacuum electron devices

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  20. Plasmodium falciparum transfected with ultra bright NanoLuc luciferase offers high sensitivity detection for the screening of growth and cellular trafficking inhibitors.

    Directory of Open Access Journals (Sweden)

    Mauro F Azevedo

    Full Text Available Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients.

  1. The Bright Universe Cosmology

    International Nuclear Information System (INIS)

    Surdin, M.

    1980-01-01

    It is shown that viewed from the 'outside', our universe is a black hole. Hence the 'inside' cosmology considered is termed as the Bright Universe Cosmology. The model proposed avoids the singularities of cosmologies of the Big Bang variety, it gives a good account of the redshifts, the cosmic background radiation, the number counts; it also gives a satisfactory explanation of the 'large numbers coincidence' and of the variation in time of fundamental constants. (Auth.)

  2. Tunable High Brightness Semiconductor Sources

    Science.gov (United States)

    2015-05-01

    red). The reflectance of the G-SAM as a function of irradiance (I) can be expressed as: R(I) = exp [ −ξ ( α◦ 1 + ξI/ Isat ) + ξβeffI)2L ] , (31) 58...resonant structures. where I is the on-axis intensity, α◦ is the linear absorption coefficient, Isat is the saturation intensity, βeff is the nonlinear...α(ξI) = α◦ 1 + ξI/ Isat + ξβeffI (32) The nonlinear reflectance of a G-SAM and dependance on the nonlinear components is shown in Figure 43 (a). The

  3. 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

  4. High gain free electron laser at ETA

    International Nuclear Information System (INIS)

    Orzechowski, T.J.; Prosnitz, D.; Halbach, K.

    1983-01-01

    A single pass, tapered electron wiggler and associated beam transport has been constructed at the Experimental Test Accelerator (ETA) at Lawrence Livermore National Laboratory (LLNL). The system is designed to transport 1 kA of 4.5 MeV electrons with an emittance of 30 millirad-cm. The planar wiggler is provided by a pulsed electromagnet. The interaction region is an oversized rectangular waveguide. Quadrupole fields stabilize the beam in the plane parallel to the wiggler field. The 3 meter long wiggler has a 9.8 cm period. The Free Electron Laser (FEL) will serve as an amplifier for input frequencies of 35 GHz and 140 GHz. The facility is designed to produce better than 500 Megawatts peak power

  5. Electron ray tracing with high accuracy

    International Nuclear Information System (INIS)

    Saito, K.; Okubo, T.; Takamoto, K.; Uno, Y.; Kondo, M.

    1986-01-01

    An electron ray tracing program is developed to investigate the overall geometrical and chromatic aberrations in electron optical systems. The program also computes aberrations due to manufacturing errors in lenses and deflectors. Computation accuracy is improved by (1) calculating electrostatic and magnetic scalar potentials using the finite element method with third-order isoparametric elements, and (2) solving the modified ray equation which the aberrations satisfy. Computation accuracy of 4 nm is achieved for calculating optical properties of the system with an electrostatic lens

  6. Selection effects in the bivariate brightness distribution for spiral galaxies

    International Nuclear Information System (INIS)

    Phillipps, S.; Disney, M.

    1986-01-01

    The joint distribution of total luminosity and characteristic surface brightness (the bivariate brightness distribution) is investigated for a complete sample of spiral galaxies in the Virgo cluster. The influence of selection and physical limits of various kinds on the apparent distribution are detailed. While the distribution of surface brightness for bright galaxies may be genuinely fairly narrow, faint galaxies exist right across the (quite small) range of accessible surface brightnesses so no statement can be made about the true extent of the distribution. The lack of high surface brightness bright galaxies in the Virgo sample relative to an overall RC2 sample (mostly field galaxies) supports the contention that the star-formation rate is reduced in the inner region of the cluster for environmental reasons. (author)

  7. High quality flux control system for electron gun evaporation

    International Nuclear Information System (INIS)

    Appelbloom, A.M.; Hadley, P.; van der Marel, D.; Mooij, J.E.

    1991-01-01

    This paper reports on a high quality flux control system for electron gun evaporation developed and tested for the MBE growth of high temperature superconductors. The system can be applied to any electron gun without altering the electron gun itself. Essential elements of the system are a high bandwidth mass spectrometer, control electronics and a high voltage modulator to sweep the electron beam over the melt at high frequencies. the sweep amplitude of the electron beam is used to control the evaporation flux at high frequencies. The feedback loop of the system has a bandwidth of over 100 Hz, which makes it possible to grow superlattices and layered structures in a fast and precisely controlled manner

  8. STANFORD: Producing highly polarized electrons (2)

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Electron spin polarization above 70% by photoemission from a specially prepared semiconductor has been achieved by T. Maruyama and E. Garwin of the Stanford Linear Accelerator Center (SLAC), R. Prepost and G. Zapalac of Wisconsin, and J. Walker and S. Smith of Berkeley

  9. Scattering of high energy electrons on deuteron

    International Nuclear Information System (INIS)

    Grossetete, B.

    1964-12-01

    The aim of this work is to obtain information on the neutron form factor from the study of the scattering of electrons on deuterium. The first part is dedicated to the theoretical study of the elastic and inelastic scattering. We introduce different form factors: Sachs form factor, the Pauli and Dirac form factors, they appear in the analytic expression of the scattering cross-section. We show how the deuteron form factors can be deduced from neutron's and proton's form factors. In the case of the inelastic scattering we show how the cross section can be broken into components associated to partial waves and we obtain different formulas for the inelastic cross-section based on the Breit formula or the Durand formalism. The second part is dedicated to the experiment setting of electron scattering on deuterium. The elastic scattering experiment has been made on solid or liquid CD 2 targets while inelastic scattering has been studied on a liquid target. We have used an electron beam produced by the Orsay linear accelerator and the scattered electrons have been analysed by a magnetic spectrometer and a Cerenkov detector. The results give a very low value (slightly positive)for the charge form factor of the neutron and a magnetic form factor for the neutron slightly below that of the proton [fr

  10. Electronic ceramics in high-temperature environments

    International Nuclear Information System (INIS)

    Searcy, A.W.; Meschi, D.J.

    1982-01-01

    Simple thermodynamic means are described for understanding and predicting the influence of temperature changes, in various environments, on electronic properties of ceramics. Thermal gradients, thermal cycling, and vacuum annealing are discussed, as well as the variations of ctivities and solubilities with temperature. 7 refs

  11. Electron beam generation in high voltage glow discharges

    International Nuclear Information System (INIS)

    Rocca, J.J.; Szapiro, B.; Murray, C.

    1989-01-01

    The generation of intense CW and pulsed electron beams in glow discharges in reviewed. Glow discharge electron guns operate at a pressure of the order of 1 Torr and often have an advantage in applications that require a broad area electron beam in a gaseous atmosphere, such as laser excitation and some aspects of materials processing. Aspects of electron gun design are covered. Diagnostics of the high voltage glow discharges including the electric field distribution mapped by Doppler free laser spectroscopy, and plasma density and electron temperature measurements of the electron yield of different cathode materials under glow discharge conditions are presented

  12. Highly solvatochromic emission of electron donor-acceptor compounds containing propanedioato boron electron acceptors

    NARCIS (Netherlands)

    Brouwer, A.M.; Bakker, N.A.C.; Wiering, P.G.; Verhoeven, J.W.

    1991-01-01

    Light-induced electron transfer occurs in bifunctional compounds consisting of 1,3-diphenylpropanedioato boron oxalate or fluoride electron acceptors and simple aromatic electron-donor groups, linked by a methylene bridge; fluorescence from the highly polar charge-transfer excited state is

  13. Highly efficient electron gun with a single-atom electron source

    International Nuclear Information System (INIS)

    Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

    2007-01-01

    The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

  14. High-Current Plasma Electron Sources

    International Nuclear Information System (INIS)

    Gushenets, J.Z.; Krokhmal, V.A.; Krasik, Ya. E.; Felsteiner, J.; Gushenets, V.

    2002-01-01

    In this report we present the design, electrical schemes and preliminary results of a test of 4 different electron plasma cathodes operating under Kg h-voltage pulses in a vacuum diode. The first plasma cathode consists of 6 azimuthally symmetrically distributed arc guns and a hollow anode having an output window covered by a metal grid. Plasma formation is initiated by a surface discharge over a ceramic washer placed between a W-made cathode and an intermediate electrode. Further plasma expansion leads to a redistribution of the discharge between the W-cathode and the hollow anode. An accelerating pulse applied between the output anode grid and the collector extracts electrons from this plasma. The operation of another plasma cathode design is based on Penning discharge for preliminary plasma formation. The main glow discharge occurs between an intermediate electrode of the Penning gun and the hollow anode. To keep the background pressure in the accelerating gap at P S 2.5x10 4 Torr either differential pumping or a pulsed gas puff valve were used. The operation of the latter electron plasma source is based on a hollow cathode discharge. To achieve a sharp pressure gradient between the cathode cavity and the accelerating gap a pulsed gas puff valve was used. A specially designed ferroelectric plasma cathode initiated plasma formation inside the hollow cathode. This type of the hollow cathode discharge ignition allowed to achieve a discharge current of 1.2 kA at a background pressure of 2x10 4 Torr. All these cathodes were developed and initially tested inside a planar diode with a background pressure S 2x10 4 Torr under the same conditions: accelerating voltage 180 - 300 kV, pulse duration 200 - 400 ns, electron beam current - 1 - 1.5 kA, and cross-sectional area of the extracted electron beam 113 cm 2

  15. Nano features of Al/Au ultrasonic bond interface observed by high resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Ji Hongjun; Li Mingyu; Kim, Jong-Myung; Kim, Dae-Won; Wang Chunqing

    2008-01-01

    Nano-scale interfacial details of ultrasonic AlSi1 wire wedge bonding to a Au/Ni/Cu pad were investigated using high resolution transmission electron microscopy (HRTEM). The intermetallic phase Au 8 Al 3 formed locally due to diffusion and reaction activated by ultrasound at the Al/Au bond interface. Multilayer sub-interfaces roughly parallel to the wire/pad interface were observed among this phase, and interdiffusional features near the Au pad resembled interference patterns, alternately dark and bright bars. Solid-state diffusion theory cannot be used to explain why such a thick compound formed within milliseconds at room temperature. The major formation of metallurgical bonds was attributed to ultrasonic cyclic vibration

  16. Electron capture by highly stripped ions

    International Nuclear Information System (INIS)

    Greenland, P.T.

    1981-06-01

    This review describes theories of electron capture suitable for the description of rearrangement collisions between atomic hydrogen and completely stripped projectiles with charge greater than unity. The region of impact velocity considered lies between 0.05 and 3 au, which is of technological importance in fusion power devices. The semiclassical, impact parameter formalism is discussed and the use of atomic expansions at medium impact velocity is described. Experimental results for both completely and partially stripped projectiles are reviewed. The use of a molecular basis at low energy, and the role of pseudocrossings peculiar to the two centre Coulomb interaction are described. Finally, purely classical techniques, in which the electron wavefunction is represented by an ensemble of Kepler orbits are considered. The review was completed in February 1981. (author)

  17. Quantitative analysis of inclusions in high-strength steels by x-ray computed tomography using ultra-bright synchrotron radiation

    International Nuclear Information System (INIS)

    Shiozawa, Daiki; Nakai, Yoshikazu; Morikage, Yasushi; Tanaka, Hiroshi; Okado, Hideki; Miyashita, Takuya

    2006-01-01

    The observation of internal microstructures in materials is important to elucidate the mechanisms of ultra-long life fatigue of high-strength steels, and to ensure the integrity of structures. By conventional techniques, such as laboratory X-ray and ultrasonic imaging, the size and shape of subsurface non-metallic inclusions and cracks, those are smaller than 100 μm, cannot be measured. Then, in the present study, the ultra-bright synchrotron radiation X-ray was applied to the imaging of subsurface inclusion. To obtain basic data for the measurement, the penetration depth of synchrotron radiation wave in a free-cutting steel was examined. It was found that the depths where the transmitted wave cannot be observed are 100 μm for 15 keV, 200 μm for 20 keV, 600 μm for 25 keV, and 800 μm for 30 keV. For the measurement of size and shape of inclusion, synchrotron radiation computed tomography method (SR-CT) was employed. Metallographic structures can be observed in a free-cutting steel, and the diameter of these structures is about 7 - 10 μm. They are considered to be inclusions, which mainly contain manganese sulfide (MnS) or pearlitic phase. To investigate the possibility of detection of pearlitic phase, SR-CT was applied to observe the metallographic structures in carbon steel (S35C), which contains a lot of pearlitic phase and a little inclusion. In this case, no metallographic structure was observed inside specimen. These results indicate that the microstructures those were observed by SR-CT method was inclusions, not pearlitic phase. (author)

  18. Bright conjugated polymer nanoparticles containing a biodegradable shell produced at high yields and with tuneable optical properties by a scalable microfluidic device.

    Science.gov (United States)

    Abelha, T F; Phillips, T W; Bannock, J H; Nightingale, A M; Dreiss, C A; Kemal, E; Urbano, L; deMello, J C; Green, M; Dailey, L A

    2017-02-02

    This study compares the performance of a microfluidic technique and a conventional bulk method to manufacture conjugated polymer nanoparticles (CPNs) embedded within a biodegradable poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) (PEG 5K -PLGA 55K ) matrix. The influence of PEG 5K -PLGA 55K and conjugated polymers cyano-substituted poly(p-phenylene vinylene) (CN-PPV) and poly(9,9-dioctylfluorene-2,1,3-benzothiadiazole) (F8BT) on the physicochemical properties of the CPNs was also evaluated. Both techniques enabled CPN production with high end product yields (∼70-95%). However, while the bulk technique (solvent displacement) under optimal conditions generated small nanoparticles (∼70-100 nm) with similar optical properties (quantum yields ∼35%), the microfluidic approach produced larger CPNs (140-260 nm) with significantly superior quantum yields (49-55%) and tailored emission spectra. CPNs containing CN-PPV showed smaller size distributions and tuneable emission spectra compared to F8BT systems prepared under the same conditions. The presence of PEG 5K -PLGA 55K did not affect the size or optical properties of the CPNs and provided a neutral net electric charge as is often required for biomedical applications. The microfluidics flow-based device was successfully used for the continuous preparation of CPNs over a 24 hour period. On the basis of the results presented here, it can be concluded that the microfluidic device used in this study can be used to optimize the production of bright CPNs with tailored properties with good reproducibility.

  19. Investigation of fundamental limits to beam brightness available from photoinjectors

    International Nuclear Information System (INIS)

    Bazarov, Ivan

    2015-01-01

    The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

  20. Investigation of fundamental limits to beam brightness available from photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Bazarov, Ivan [Cornell Univ., Ithaca, NY (United States)

    2015-07-09

    The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

  1. ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS

    International Nuclear Information System (INIS)

    Wei, J.; Macek, R.J.

    2002-01-01

    One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures

  2. ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; MACEK,R.J.

    2002-04-14

    One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

  3. High Resolution Electron Microscopy in Materials Science

    International Nuclear Information System (INIS)

    Amelinckx, S.

    1986-01-01

    This paper illustrates different operating modes of the electron microscope and shows the image formation in an ideal microscope. Diffraction contrast is used in the study of crystal defects, such as dislocations and planar interfaces. Methods are surveyed which give at least a rudimentary image of the lattice and therefore make use of at least two interfering beams. Special attention is given to images which also carry structural information and therefore imply the use of many beams. The underlying theory is discussed as are the theories of Van Dyck, Spence and Cowley. These are illustrated by means of a number of recent case studies

  4. LAT Perspectives in Detection of High Energy Cosmic Ray Electrons

    International Nuclear Information System (INIS)

    Moiseev, Alexander; Ormes, J.F.; Funk, Stefan

    2007-01-01

    The LAT science objectives and capabilities in the detection of high energy electrons in the energy range from 20 GeV to ∼1.5 TeV are presented. LAT simulations are used to establish the event selections. It is found that maintaining the efficiency of electron detection at the level of 30%, the residual hadron contamination does not exceed 2-3% of the electron flux. It is expected to collect ∼ ten million of electrons with the energy above 20 GeV for one year of observation. Precise spectrum reconstruction with collected electron statistics opens the unique opportunity to investigate several important problems such as models of IC radiation, revealing the signatures of nearby sources such as high energy cutoff in the electron spectrum, testing the propagation model, and search for KKDM particles decay through their contribution to the electron spectrum

  5. On some aspects of high voltage electron microscopy

    International Nuclear Information System (INIS)

    Jouffrey, B.; Trinquier, J.

    1987-01-01

    The present paper deals with high voltage electron microscopy (HVEM). It is an overview on this domain due to the pionneer work of G. Dupouy which has permitted to perform a new kind of electron microscopy. Since this time, HVEM has shown its interest in high resolution, irradiations, chemical analysis, in situ experiments

  6. On the electronic structure of high Tc superconductors

    International Nuclear Information System (INIS)

    Fink, J.; Nuecker, N.; Romberg, H.; Alexander, M.; Knupfer, M.; Mante, J.; Claessen, R.; Buslaps, T.; Harm, S.; Manzke, R.; Skibowski, M.

    1992-01-01

    Studies of the electronic structure of high-T c superconductors and related compounds by high-energy spectroscopies are reviewed. In particular, we report on investigations by electron energy-loss, angle-resolved photoemission, and inverse angle-resolved photoemission spectroscopy. Information on the symmetry and the character of states close to the Fermi level has been obtained. 25 refs., 8 figs

  7. Electron acceleration via high contrast laser interacting with submicron clusters

    International Nuclear Information System (INIS)

    Zhang Lu; Chen Liming; Wang Weiming; Yan Wenchao; Yuan Dawei; Mao Jingyi; Wang Zhaohua; Liu Cheng; Shen Zhongwei; Li Yutong; Dong Quanli; Lu Xin; Ma Jinglong; Wei Zhiyi; Faenov, Anatoly; Pikuz, Tatiana; Li Dazhang; Sheng Zhengming; Zhang Jie

    2012-01-01

    We experimentally investigated electron acceleration from submicron size argon clusters-gas target irradiated by a 100 fs, 10 TW laser pulses having a high-contrast. Electron beams are observed in the longitudinal and transverse directions to the laser propagation. The measured energy of the longitudinal electron reaches 600 MeV and the charge of the electron beam in the transverse direction is more than 3 nC. A two-dimensional particle-in-cell simulation of the interaction has been performed and it shows an enhancement of electron charge by using the cluster-gas target.

  8. 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.

  9. Bright triplet excitons in caesium lead halide perovskites

    Science.gov (United States)

    Becker, Michael A.; Vaxenburg, Roman; Nedelcu, Georgian; Sercel, Peter C.; Shabaev, Andrew; Mehl, Michael J.; Michopoulos, John G.; Lambrakos, Samuel G.; Bernstein, Noam; Lyons, John L.; Stöferle, Thilo; Mahrt, Rainer F.; Kovalenko, Maksym V.; Norris, David J.; Rainò, Gabriele; Efros, Alexander L.

    2018-01-01

    Nanostructured semiconductors emit light from electronic states known as excitons. For organic materials, Hund’s rules state that the lowest-energy exciton is a poorly emitting triplet state. For inorganic semiconductors, similar rules predict an analogue of this triplet state known as the ‘dark exciton’. Because dark excitons release photons slowly, hindering emission from inorganic nanostructures, materials that disobey these rules have been sought. However, despite considerable experimental and theoretical efforts, no inorganic semiconductors have been identified in which the lowest exciton is bright. Here we show that the lowest exciton in caesium lead halide perovskites (CsPbX3, with X = Cl, Br or I) involves a highly emissive triplet state. We first use an effective-mass model and group theory to demonstrate the possibility of such a state existing, which can occur when the strong spin-orbit coupling in the conduction band of a perovskite is combined with the Rashba effect. We then apply our model to CsPbX3 nanocrystals, and measure size- and composition-dependent fluorescence at the single-nanocrystal level. The bright triplet character of the lowest exciton explains the anomalous photon-emission rates of these materials, which emit about 20 and 1,000 times faster than any other semiconductor nanocrystal at room and cryogenic temperatures, respectively. The existence of this bright triplet exciton is further confirmed by analysis of the fine structure in low-temperature fluorescence spectra. For semiconductor nanocrystals, which are already used in lighting, lasers and displays, these excitons could lead to materials with brighter emission. More generally, our results provide criteria for identifying other semiconductors that exhibit bright excitons, with potential implications for optoelectronic devices.

  10. CAMAC high energy physics electronics hardware

    International Nuclear Information System (INIS)

    Kolpakov, I.F.

    1977-01-01

    CAMAC hardware for high energy physics large spectrometers and control systems is reviewed as is the development of CAMAC modules at the High Energy Laboratory, JINR (Dubna). The total number of crates used at the Laboratory is 179. The number of CAMAC modules of 120 different types exceeds 1700. The principles of organization and the structure of developed CAMAC systems are described. (author)

  11. Electronic DC transformer with high power density

    NARCIS (Netherlands)

    Pavlovský, M.

    2006-01-01

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

  12. Overlap of electron core states for very high compressions

    International Nuclear Information System (INIS)

    Straub, G.

    1985-01-01

    At normal density and for modest compressions, the electronic structure of a metal can be accurately described by treating the conduction electrons and their interactions with the usual methods of band theory. The core electrons remain essentially the same as for an isolated free atom and do not participate in the bonding forces responsible for creating a condensed phase. As the density increases, the core electrons begin to ''see'' one another as the overlap of the tails of wave functions can no longer be neglected. The electronic structure of the core electrons is responsible for an effective repulsive interaction that eventually becomes free-electron-like at very high compressions. The electronic structure of the interacting core electrons may be treated in a simple manner using the Atomic Surface Method (ASM). The ASM is a first-principles treatment of the electronic structure involving a rigorous integration of the Schroedinger equation within the atomic-sphere approximation. Solid phase wave functions are constructed from isolated atom wave functions and the band width W/sub l/ and the center of gravity of the band C/sub l/ are obtained from simple formulas. The ASM can also utilize analytic forms of the atomic wave functions and thus provide direct functional dependence of various aspects of the electronic structure. Of particular use in understanding the behavior of the core electrons, the ASM provides the analytic density dependence of the band widths and positions. 8 refs., 2 figs., 1 tab

  13. Electron linac injector developments

    International Nuclear Information System (INIS)

    Fraser, J.S.

    1986-01-01

    There is a continuing demand for improved injectors for electron linacs. Free-electron laser (FEL) oscillators require pulse trains of high brightness and, in some applications, high average power at the same time. Wakefield-accelerator and laser-acceleration experiments require isolated bunches of high peak brightness. Experiments with alkali-halide photoemissive and thermionic electron sources in rf cavities for injector applications are described. For isolated pulses, metal photocathodes (illuminated by intense laser pulses) are being employed. Reduced emittance growth in high-peak-current electron injectors may be achieved by linearizing the cavity electric field's radial component and by using high field strengths at the expense of lower shunt impedance. Harmonically excited cavities have been proposed for enlarging the phase acceptance of linac cavities and thereby reducing the energy spread produced in the acceleration process. Operation of injector linacs at a subharmonic of the main linac frequency is also proposed for enlarging the phase acceptance

  14. Influence of high energy electrons on ECRH in LHD

    Directory of Open Access Journals (Sweden)

    Ogasawara S.

    2012-09-01

    Full Text Available The central bulk electron temperature of more than 20 keV is achieved in LHD as a result of increasing the injection power and the lowering the electron density near 2 × 1018 m−3. Such collision-less regime is important from the aspect of the neoclassical transport and also the potential structure formation. The presences of appreciable amount of high energy electrons are indicated from hard X-ray PHA, and the discrepancy between the stored energy and kinetic energy estimated from Thomson scattering. ECE spectrum are also sensitive to the presence of high energy electrons and discussed by solving the radiation transfer equation. The ECRH power absorption to the bulk and the high energy electrons are dramatically affected by the acceleration and the confinement of high energy electrons. The heating mechanisms and the acceleration process of high energy electrons are discussed by comparing the experimental results and the ray tracing calculation under assumed various density and mean energy of high energy electrons.

  15. Formation of a high quality electron beam using photo cathode RF electron gun

    International Nuclear Information System (INIS)

    Washio, Masakazu

    2000-01-01

    Formation of a high quality electron beam using photo cathode RF electron gun is expected for formation of a next generation high brilliant X-ray beam and a source for electron and positron collider. And, on a field of material science, as is possible to carry out an experiment under ultra short pulse and extremely high precision in time, it collects large expectation. Recently, formation of high quality beam possible to develop for multi directions and to use by everyone in future has been able to realize. Here were explained on electron beam source, principle and component on RF electron gun, working features on RF gun, features and simulation of RF gun under operation, and some views in near future. (G.K.)

  16. Nanostructures for Very High Frequency Electronics

    National Research Council Canada - National Science Library

    Gelmont, Boris

    2002-01-01

    The study of a new class of mesoscopic high frequency semi-conductor devices based on resonant tunneling in staggered-bandgap heterostructures with III-V semi-conductor ternary alloys such as AlGaSb...

  17. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    Energy Technology Data Exchange (ETDEWEB)

    Grillo, Vincenzo, E-mail: vincenzo.grillo@nano.cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Carlo Gazzadi, Gian [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Karimi, Ebrahim [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy)

    2014-01-27

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

  18. Ion induced high energy electron emission from copper

    International Nuclear Information System (INIS)

    Ruano, G.; Ferron, J.

    2008-01-01

    We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He + , Ne + and Ar + ) and Li + ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

  19. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    International Nuclear Information System (INIS)

    Grillo, Vincenzo; Carlo Gazzadi, Gian; Karimi, Ebrahim; Mafakheri, Erfan; Boyd, Robert W.; Frabboni, Stefano

    2014-01-01

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science

  20. First high-temperature electronics products survey 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy Allen

    2006-04-01

    On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

  1. Apparatus and method for generating high density pulses of electrons

    International Nuclear Information System (INIS)

    Lee, C.; Oettinger, P.E.

    1981-01-01

    An apparatus and method are described for the production of high density pulses of electrons using a laser energized emitter. Caesium atoms from a low pressure vapour atmosphere are absorbed on and migrate from a metallic target rapidly heated by a laser to a high temperature. Due to this heating time being short compared with the residence time of the caesium atoms adsorbed on the target surface, copious electrons are emitted which form a high current density pulse. (U.K.)

  2. Properties of the electron cloud in a high-energy positron and electron storage ring

    International Nuclear Information System (INIS)

    Harkay, K.C.; Rosenberg, R.A.

    2003-01-01

    Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in a positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-23

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

  4. Development of an electron gun for high power CW electron linac

    International Nuclear Information System (INIS)

    Yamazaki, Yoshio; Nomura, Masahiro

    1994-01-01

    An electron gun launching high average current beam has been designed for the high power CW electron linac at PNC. A peak electron beam current of 400mA with beam energy 200keV is required from the buncher design. However its average current is very high(duty factor 20%), a mesh grid is not able to be used for current control because of heating up or melting of grid. Furthermore, the beam current have to be variable up to 400mA to match with downstream modules, especially the accelerating guides including recirculating system. We employed the electron gun with two aperture grids to control beam current. The dimension of the electrodes, electron trajectory, the size of beam radius, and gun emittance was simulated by EGUN. (author)

  5. Heat sinking of highly integrated photonic and electronic circuits

    NARCIS (Netherlands)

    van Rijn, M.B.J.; Smit, M.K.

    2017-01-01

    Dense integration of photonic and electronic circuits poses high requirements on thermal management. In this paper we present analysis of temperature distributions in PICs in InP membranes on top of a BiCMOS chip, which contain hot spots in both the photonic and the electronic layer (lasers, optical

  6. A high dutycycle low cost multichannel analyser for electron spectroscopy

    International Nuclear Information System (INIS)

    Norell, K.E.; Baltzer, P.

    1983-03-01

    A high dutycycle multichannel analyzer has been designed and used in time-of-flight electron spectroscopy. The memory capacity is 64k counts. The number of channels is 8192 with a time resolution of 100 ns. An oscilloscope is used to display the spectra synchronous with the counting. The unit has been built with standard electronic components. (author)

  7. Electron-optical design parameters for a high-resolution electron monochromator

    International Nuclear Information System (INIS)

    Tanaka, H.; Huebner, R.H.

    1976-01-01

    Detailed design parameters of a new, high-resolution electron monochromator are presented. The design utilizes a hemispherical filter as the energy-dispersing element and combines both cylindrical and aperture electrostatic lenses to accelerate, decelerate, transport, and focus the electron beam from the cathode to the interaction region

  8. High energy electron acceleration with PW-class laser system

    International Nuclear Information System (INIS)

    Nakanii, N.; Kondo, K.; Yabuuchi, T.; Tsuji, K.; Kimura, K.; Fukumochi, S.; Kashihara, M.; Tanimoto, T.; Nakamura, H.; Ishikura, T.; Kodama, R.; Mima, K.; Tanaka, K. A.; Mori, Y.; Miura, E.; Suzuki, S.; Asaka, T.; Yanagida, K.; Hanaki, H.; Kobayashi, T.

    2008-01-01

    We performed electron acceleration experiment with PW-class laser and a plasma tube, which was created by imploding a hollow polystyrene cylinder. In this experiment, electron energies in excess of 600 MeV have been observed. Moreover, the spectra of a comparatively high-density plasma ∼10 19 cm -3 had a bump around 10 MeV. Additionally, we performed the absolute sensitivity calibration of imaging plate for 1 GeV electrons from the injector Linac of Spring-8 in order to evaluate absolute number of GeV-class electrons in the laser acceleration experiment

  9. Evaluation of high-energy brachytherapy source electronic disequilibrium and dose from emitted electrons.

    Science.gov (United States)

    Ballester, Facundo; Granero, Domingo; Pérez-Calatayud, José; Melhus, Christopher S; Rivard, Mark J

    2009-09-01

    The region of electronic disequilibrium near photon-emitting brachytherapy sources of high-energy radionuclides (60Co, 137CS, 192Ir, and 169Yb) and contributions to total dose from emitted electrons were studied using the GEANT4 and PENELOPE Monte Carlo codes. Hypothetical sources with active and capsule materials mimicking those of actual sources but with spherical shape were examined. Dose contributions due to source photons, x rays, and bremsstrahlung; source beta-, Auger electrons, and internal conversion electrons; and water collisional kerma were scored. To determine if conclusions obtained for electronic equilibrium conditions and electron dose contribution to total dose for the representative spherical sources could be applied to actual sources, the 192Ir mHDR-v2 source model (Nucletron B.V., Veenendaal, The Netherlands) was simulated for comparison to spherical source results and to published data. Electronic equilibrium within 1% is reached for 60Co, 137CS, 192Ir, and 169Yb at distances greater than 7, 3.5, 2, and 1 mm from the source center, respectively, in agreement with other published studies. At 1 mm from the source center, the electron contributions to total dose are 1.9% and 9.4% for 60Co and 192Ir, respectively. Electron emissions become important (i.e., > 0.5%) within 3.3 mm of 60Co and 1.7 mm of 192Ir sources, yet are negligible over all distances for 137Cs and 169Yb. Electronic equilibrium conditions along the transversal source axis for the mHDR-v2 source are comparable to those of the spherical sources while electron dose to total dose contribution are quite different. Electronic equilibrium conditions obtained for spherical sources could be generalized to actual sources while electron contribution to total dose depends strongly on source dimensions, material composition, and electron spectra.

  10. Technical Training: ELEC-2005: Electronics in High Energy Physics

    CERN Multimedia

    Monique Duval

    2005-01-01

    CERN Technical Training 2005: Learning for the LHC! ELEC-2005: Electronics in High Energy Physics - Spring Term ELEC-2005 is a new course series on modern electronics, given by CERN physicists and engineers within the framework of the 2005 Technical Training Programme, in an extended format of the successful ELEC-2002 course series. This comprehensive course series is designed for people who are not electronics specialists, for example physicists, engineers and technicians working at or visiting the laboratory, who use or will use electronics in their present or future activities, in particular in the context of the LHC accelerator and experiments. ELEC-2005 is composed of four Terms: the Winter Term, Introduction to electronics in HEP, already took place; the next three Terms will run throughout the year: Spring Term: Integrated circuits and VLSI technology for physics (March, 6 lectures) - now open for registration Summer Term: System electronics for physics: Issues (May, 7 lectures) Autumn Term: Ele...

  11. Development techniques and electron optical studies of high voltage, high current electron guns

    International Nuclear Information System (INIS)

    Rangarajan, L.M.; Mahadevan, S.; Ramamurthi, S.S.

    1992-01-01

    The progress of the electron gun design, limiting to axially symmetric geometries is discussed here with a view to utilise such guns for electron accelerators. The mechanical design features leading to the physical configuration of the gun with stringent tolerances are outlined. Vacuum processing is done at pressures of 1.3x10 -5 Pa. The gun employs W-filament emitter or a cathode pellet with bombarder service. A water cooled compact faraday cup is used to measure the electron current. Electron gun geometries have been studied using the computer programme. The preveance of the gun is 0.7x10 -7 A/Vsup(1.5) at 80 kV. Developmental techniques of such pulsed electron guns are described. (author). 7 refs., 5 figs

  12. Organic High Electron Mobility Transistors Realized by 2D Electron Gas.

    Science.gov (United States)

    Zhang, Panlong; Wang, Haibo; Yan, Donghang

    2017-09-01

    A key breakthrough in inorganic modern electronics is the energy-band engineering that plays important role to improve device performance or develop novel functional devices. A typical application is high electron mobility transistors (HEMTs), which utilizes 2D electron gas (2DEG) as transport channel and exhibits very high electron mobility over traditional field-effect transistors (FETs). Recently, organic electronics have made very rapid progress and the band transport model is demonstrated to be more suitable for explaining carrier behavior in high-mobility crystalline organic materials. Therefore, there emerges a chance for applying energy-band engineering in organic semiconductors to tailor their optoelectronic properties. Here, the idea of energy-band engineering is introduced and a novel device configuration is constructed, i.e., using quantum well structures as active layers in organic FETs, to realize organic 2DEG. Under the control of gate voltage, electron carriers are accumulated and confined at quantized energy levels, and show efficient 2D transport. The electron mobility is up to 10 cm 2 V -1 s -1 , and the operation mechanisms of organic HEMTs are also argued. Our results demonstrate the validity of tailoring optoelectronic properties of organic semiconductors by energy-band engineering, offering a promising way for the step forward of organic electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Secondary electron spectroscopy and Auger microscopy at high spatial resolution. Application to scanning electron microscopy

    International Nuclear Information System (INIS)

    Le Gressus, Claude; Massignon, Daniel; Sopizet, Rene

    1979-01-01

    Secondary electron spectroscopy (SES), Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS) are combined with ultra high vacuum scanning microscopy (SEM) for surface analysis at high spatial resolution. Reliability tests for the optical column for the vacuum and for the spectrometer are discussed. Furthermore the sensitivity threshold in AES which is compatible with a non destructive surface analysis at high spatial resolution is evaluated. This combination of all spectroscopies is used in the study of the beam damage correlated with the well known secondary electron image (SEI) darkening still observed in ultra high vacuum. The darkening is explained as a bulk decontamination of the sample rather than as a surface contamination from the residual vacuum gas [fr

  14. Practical XHV electron gun

    International Nuclear Information System (INIS)

    Urata, Tomohiro; Ishikawa, Tsuyoshi; Cho, Boklae; Oshima, Chuhei

    2008-01-01

    We have developed practical XHV chambers of a electron gun, of which the operating pressures are 1x10 -9 Pa in a stainless-steel one and 4x10 -9 Pa in a permalloy one. By mounting a noble single-atom electron source with high brightness and high spatial coherence on the electron gun including electron optics, we demonstrated highly collimated electron-beam emission: ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources. In XHV, in addition, we confirmed stable electron emission up to 20 nA, which results in the specimen current high enough for scanning electron microscopes. (author)

  15. Treatment of basal cell epithelioma with high energy electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Y. (Hyogo-ken Cancer Center, Kobe (Japan)); Kumano, M.; Kumano, K.

    1981-11-01

    Thirty patients with basal cell epithelioma received high energy electron beam therapy. They were irradiated with a dose ranging from 4,800 rad (24 fractions, 35 days) to 12,000 rad (40 fractions, 57 days). Tumors disappeared in all cases. These were no disease-related deaths; in one patient there was recurrence after 2 years. We conclude that radiotherapy with high energy electron beam is very effective in the treatment of basal cell epithelioma.

  16. 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

  17. Optical Thermal Characterization Enables High-Performance Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    2016-02-01

    NREL developed a modeling and experimental strategy to characterize thermal performance of materials. The technique provides critical data on thermal properties with relevance for electronics packaging applications. Thermal contact resistance and bulk thermal conductivity were characterized for new high-performance materials such as thermoplastics, boron-nitride nanosheets, copper nanowires, and atomically bonded layers. The technique is an important tool for developing designs and materials that enable power electronics packaging with small footprint, high power density, and low cost for numerous applications.

  18. Simultaneous brightness contrast of foraging Papilio butterflies

    Science.gov (United States)

    Kinoshita, Michiyo; Takahashi, Yuki; Arikawa, Kentaro

    2012-01-01

    This study focuses on the sense of brightness in the foraging Japanese yellow swallowtail butterfly, Papilio xuthus. We presented two red discs of different intensity on a grey background to butterflies, and trained them to select one of the discs. They were successfully trained to select either a high intensity or a low intensity disc. The trained butterflies were tested on their ability to perceive brightness in two different protocols: (i) two orange discs of different intensity presented on the same intensity grey background and (ii) two orange discs of the same intensity separately presented on a grey background that was either higher or lower in intensity than the training background. The butterflies trained to high intensity red selected the orange disc of high intensity in protocol 1, and the disc on the background of low intensity grey in protocol 2. We obtained similar results in another set of experiments with purple discs instead of orange discs. The choices of the butterflies trained to low intensity red were opposite to those just described. Taken together, we conclude that Papilio has the ability to learn brightness and darkness of targets independent of colour, and that they have the so-called simultaneous brightness contrast. PMID:22179808

  19. High harmonic terahertz confocal gyrotron with nonuniform electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Wenjie; Guan, Xiaotong; Yan, Yang [THz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2016-01-15

    The harmonic confocal gyrotron with nonuniform electron beam is proposed in this paper in order to develop compact and high power terahertz radiation source. A 0.56 THz third harmonic confocal gyrotron with a dual arc section nonuniform electron beam has been designed and investigated. The studies show that confocal cavity has extremely low mode density, and has great advantage to operate at high harmonic. Nonuniform electron beam is an approach to improve output power and interaction efficiency of confocal gyrotron. A dual arc beam magnetron injection gun for designed confocal gyrotron has been developed and presented in this paper.

  20. Survey of potential electronic applications of high temperature superconductors

    International Nuclear Information System (INIS)

    Hammond, R.B.; Bourne, L.C.

    1991-01-01

    In this paper the authors present a survey of the potential electronic applications of high temperature superconductor (HTSC) thin films. During the past four years there has been substantial speculation on this topic. The authors will cover only a small fraction of the potential electronic applications that have been identified. Their treatment is influenced by the developments over the past few years in materials and device development and in market analysis. They present their view of the most promising potential applications. Superconductors have two important properties that make them attractive for electronic applications. These are (a) low surface resistance at high frequencies, and (b) the Josephson effect

  1. High-voltage pulse generator for electron gun power supply

    International Nuclear Information System (INIS)

    Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.

    1987-01-01

    High-voltage pulse generator with combined capacitive and inductive energy storages for electron gun power supply is described. Hydrogen thyratron set in a short magnetic lense is a current breaker. Times of current interruption in thyratrons are in the range from 100 to 300 ns. With 1 kV charging voltage of capacitive energy storage 25 kV voltage pulse is obtained in the load. The given high-voltage pulse generator was used for supply of an electron gun generating 10-30 keV low-energy electron beam

  2. Impact of electron-electron Coulomb interaction on the high harmonic generation process in graphene

    Science.gov (United States)

    Avetissian, H. K.; Mkrtchian, G. F.

    2018-03-01

    Generation of high harmonics in a monolayer graphene initiated by a strong coherent radiation field, taking into account electron-electron Coulomb interaction, is investigated. A microscopic theory describing the nonlinear optical response of graphene is developed. The Coulomb interaction of electrons is treated in the scope of dynamic Hartree-Fock approximation. The closed set of integrodifferential equations for the single-particle density matrix of a graphene quantum structure is solved numerically. The obtained solutions show the significance of many-body Coulomb interaction on the high harmonic generation process in graphene.

  3. Bright new world

    Energy Technology Data Exchange (ETDEWEB)

    Kroó, Norbert; Rácz, Péter [Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Institute for Solid State Physics and Optics, H-1525 Budapest, Pf. 49 (Hungary); Varró, Sándor [Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Institute for Solid State Physics and Optics, H-1525 Budapest, Pf. 49 (Hungary); ELI-ALPS, ELI-Hu Nonprofit Kft., Dugonics tér 13, H-6720 Szeged (Hungary)

    2016-02-15

    Surface plasmons (SPOs) have been excited by intense femtosecond laser pulses on a gold film at room temperature and their near field has been analyzed by the intensity dependent response of an STM and by studying the spectra of multiplasmon emitted electrons. Around 80 GW/cm{sup 2} laser intensity, anomalies have been found in both cases, interpreted as the stepping in of electron pairing, transition to a diamagnetic state, and by anomalous Faraday rotation.

  4. High energy gain electron beam acceleration by 100TW laser

    International Nuclear Information System (INIS)

    Kotaki, Hideyuki; Kando, Masaki; Kondo, Shuji; Hosokai, Tomonao; Kanazawa, Shuhei; Yokoyama, Takashi; Matoba, Toru; Nakajima, Kazuhisa

    2001-01-01

    A laser wakefield acceleration experiment using a 100TW laser is planed at JAERI-Kansai. High quality and short pulse electron beams are necessary to accelerate the electron beam by the laser. Electron beam - laser synchronization is also necessary. A microtron with a photocathode rf-gun was prepared as a high quality electron injector. The quantum efficiency (QE) of the photocathode of 2x10 -5 was obtained. A charge of 100pC from the microtron was measured. The emittance and pulse width of the electron beam was 6π mm-mrad and 10ps, respectively. In order to produce a short pulse electron beam, and to synchronize between the electron beam and the laser pulse, an inverse free electron laser (IFEL) is planned. One of problems of LWFA is the short acceleration length. In order to overcome the problem, a Z-pinch plasma waveguide will be prepared as a laser wakefield acceleration tube for 1 GeV acceleration. (author)

  5. Temporal and spatial distribution of high energy electrons at Jupiter

    Science.gov (United States)

    Jun, I.; Garrett, H. B.; Ratliff, J. M.

    2003-04-01

    Measurements of the high energy, omni-directional electron environment by the Galileo spacecraft Energetic Particle Detector (EPD) were used to study the high energy electron environment in the Jovian magnetosphere, especially in the region between 8 to 18 Rj (1 Rj = 1 Jovian radius = 71,400 km). 10-minute averages of the EPD data collected between Jupiter orbit insertion (JOI) in 1995 and the orbit number 33 (I33) in 2002 form an extensive dataset, which has been extremely useful to observe temporal and spatial variability of the Jovian high energy electron environment. The count rates of the EPD electron channels (0.174, 0.304, 0.527, 1.5, 2.0, and 11 MeV) were grouped into 0.5 Rj or 0.5 L bins and analyzed statistically. The results indicate that: (1) a log-normal Gaussian distribution well describes the statistics of the high energy electron environment (for example, electron differential fluxes) in the Jovian magnetosphere, in the region studied here; (2) the high energy electron environments inferred by the Galileo EPD measurements are in a close agreement with the data obtained using the Divine model, which was developed more than 30 years ago from Pioneer 10, 11 and Voyager 1, 2 data; (3) the data are better organized when plotted against magnetic radial parameter L than Rj; (4) the standard deviations of the 0.174, 0.304, 0.527 MeV channel count rates are larger than those of the 1.5, 2.0, 11 MeV count rates in 12 Rj. These observations are very helpful to understand short- and long-term, and local variability of the Jovian high energy electron environment, and are discussed in detail.

  6. Development of a high power free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Min; Lee, Byung Chul; Kim, Sun Kook; Jung, Yung Wook; Cho, Sung Oh [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-01-01

    A millimeter-wave free electron laser (FEL) driven by a recirculating electrostatic accelerator has been developed. The wavelength of the FEL is tunable in the range of 3 - 12 mm by tuning the energy of the electron beam. The output power is estimated to be 1 kW. The electrostatic accelerator is composed of high-current electron gun, acceleration tube, high-voltage generator, high-voltage terminal, deceleration tube, electron collator, and vacuum pumps. Two types of LaB{sub 6}-based thermionic electron guns (triode gun and diode gun) and their power supplies have been developed. The voltage of the guns is 30 kV and the output current is - 2 A. A beam-focusing planar undulator and a permanent-magnet helical undulator have been developed and 3D trajectories of electron beam in the undulators have been calculated to find optimal input condition of electron beam. 135 figs, 15 pix, 17 tabs, 98 refs. (Author).

  7. Development of a high power free-electron laser

    International Nuclear Information System (INIS)

    Lee, Jong Min; Lee, Byung Chul; Kim, Sun Kook; Jung, Yung Wook; Cho, Sung Oh

    1995-01-01

    A millimeter-wave free electron laser (FEL) driven by a recirculating electrostatic accelerator has been developed. The wavelength of the FEL is tunable in the range of 3 - 12 mm by tuning the energy of the electron beam. The output power is estimated to be 1 kW. The electrostatic accelerator is composed of high-current electron gun, acceleration tube, high-voltage generator, high-voltage terminal, deceleration tube, electron collator, and vacuum pumps. Two types of LaB 6 -based thermionic electron guns (triode gun and diode gun) and their power supplies have been developed. The voltage of the guns is 30 kV and the output current is - 2 A. A beam-focusing planar undulator and a permanent-magnet helical undulator have been developed and 3D trajectories of electron beam in the undulators have been calculated to find optimal input condition of electron beam. 135 figs, 15 pix, 17 tabs, 98 refs. (Author)

  8. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    International Nuclear Information System (INIS)

    Bohn, C.L.

    1997-01-01

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 μm wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design

  9. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-06-01

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design.

  10. Electron transfer and decay processes of highly charged iodine ions

    International Nuclear Information System (INIS)

    Sakaue, Hiroyuki A.; Danjo, Atsunori; Hosaka, Kazumoto

    2005-01-01

    In the present experimental work we have investigated multi-electron transfer processes in I q+ (q=10, 15, 20 and 25) + Ne, Ar, Kr and Xe collisions at 1.5q keV energy. The branching ratios between Auger and radiative decay channels have been measured in decay processes of multiply excited states formed by multi-electron transfer collisions. It has been shown that, in all the multi-electron transfer processes investigated, the Auger decays are far dominant over the radiative decay processes and the branching ratios are clearly characterized by the average principal quantum number of the initial excited states of projectile ions. We could express the branching ratios in high Rydberg states formed in multi-electron transfer processes by using the decay probability of one Auger electron emission. (author)

  11. Laboratory design for high-performance electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    O' Keefe, Michael A.; Turner, John H.; Hetherington, Crispin J.D.; Cullis, A.G.; Carragher, Bridget; Jenkins, Ron; Milgrim, Julie; Milligan,Ronald A.; Potter, Clinton S.; Allard, Lawrence F.; Blom, Douglas A.; Degenhardt, Lynn; Sides, William H.

    2004-04-23

    Proliferation of electron microscopes with field emission guns, imaging filters and hardware spherical aberration correctors (giving higher spatial and energy resolution) has resulted in the need to construct special laboratories. As resolutions improve, transmission electron microscopes (TEMs) and scanning transmission electron microscopes (STEMs) become more sensitive to ambient conditions. State-of-the-art electron microscopes require state-of-the-art environments, and this means careful design and implementation of microscope sites, from the microscope room to the building that surrounds it. Laboratories have been constructed to house high-sensitive instruments with resolutions ranging down to sub-Angstrom levels; we present the various design philosophies used for some of these laboratories and our experiences with them. Four facilities are described: the National Center for Electron Microscopy OAM Laboratory at LBNL; the FEGTEM Facility at the University of Sheffield; the Center for Integrative Molecular Biosciences at TSRI; and the Advanced Microscopy Laboratory at ORNL.

  12. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  13. Electron capture by highly charged ions from surfaces and gases

    International Nuclear Information System (INIS)

    Allen, F.

    2008-01-01

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar 17+ and Ar 18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge-selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar 17+ and Ar 18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar 16+ and Xe 44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  14. Ultra high energy electrons powered by pulsar rotation.

    Science.gov (United States)

    Mahajan, Swadesh; Machabeli, George; Osmanov, Zaza; Chkheidze, Nino

    2013-01-01

    A new mechanism of particle acceleration, driven by the rotational slow down of the Crab pulsar, is explored. The rotation, through the time dependent centrifugal force, can efficiently excite unstable Langmuir waves in the electron-positron (hereafter e(±)) plasma of the star magnetosphere. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV (~ 100 TeV) and even PeV energy domain. It is expected that the proposed mechanism may, unravel the puzzle of the origin of ultra high energy cosmic ray electrons.

  15. Flux and brightness calculations for various synchrotron radiation sources

    International Nuclear Information System (INIS)

    Weber, J.M.; Hulbert, S.L.

    1991-11-01

    Synchrotron radiation (SR) storage rings are powerful scientific and technological tools. The first generation of storage rings in the US., e.g., SURF (Washington, D.C.), Tantalus (Wisconsin), SSRL (Stanford), and CHESS (Cornell), revolutionized VUV, soft X-ray, and hard X-ray science. The second (present) generation of storage rings, e.g. the NSLS VUV and XRAY rings and Aladdin (Wisconsin), have sustained the revolution by providing higher stored currents and up to a factor of ten smaller electron beam sizes than the first generation sources. This has made possible a large number of experiments that could not performed using first generation sources. In addition, the NSLS XRAY ring design optimizes the performance of wigglers (high field periodic magnetic insertion devices). The third generation storage rings, e.g. ALS (Berkeley) and APS (Argonne), are being designed to optimize the performance of undulators (low field periodic magnetic insertion devices). These extremely high brightness sources will further revolutionize x-ray science by providing diffraction-limited x-ray beams. The output of undulators and wigglers is distinct from that of bending magnets in magnitude, spectral shape, and in spatial and angular size. Using published equations, we have developed computer programs to calculate the flux, central intensity, and brightness output bending magnets and selected wigglers and undulators of the NSLS VUV and XRAY rings, the Advanced Light Source (ALS), and the Advanced Photon Source (APS). Following is a summary of the equations used, the graphs and data produced, and the computer codes written. These codes, written in the C programming language, can be used to calculate the flux, central intensity, and brightness curves for bending magnets and insertion devices on any storage ring

  16. Ion induced high energy electron emission from copper

    Energy Technology Data Exchange (ETDEWEB)

    Ruano, G. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)], E-mail: gdruano@ceride.gov.ar; Ferron, J. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina); Departamento de Ingenieria de Materiales, Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)

    2008-11-15

    We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He{sup +}, Ne{sup +} and Ar{sup +}) and Li{sup +} ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

  17. Proposal to detect an emission of unusual super-high energy electrons in electron storage rings

    Directory of Open Access Journals (Sweden)

    Da-peng Qian

    2014-01-01

    Full Text Available According to an extended Lorentz–Einstein mass formula taken into the uncertainty principle, it is predicted that the electron beams passing accelerating electric field should with a small probability generate abnormal super-high energy electrons which are much higher than the beam energy. Author’s preliminary experiment result at electron storage ring has hinted these signs, so suggests to more strictly detect this unusual phenomenon, and thus to test the extended mass formula as well as a more perfect special relativity.

  18. Electron Acceleration by High Power Radio Waves in the Ionosphere

    Science.gov (United States)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  19. Electron-cloud effects in high-luminosity colliders

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, F.

    1998-01-01

    Electron-cloud instabilities are expected to be important in most high-luminosity double-ring colliders. In this report, the author describes a few parameter regimes and some critical parameter dependences of this type of instability, and illustrate these with simulation results for the PEP-II and KEK B factories, the LHC, the VLHC, and DAPHNE. In addition, the author studies the possibility and the potential impact of an electron cloud in the interaction region.

  20. Electron spectroscopy on high-temperature superconductors and related compounds

    International Nuclear Information System (INIS)

    Knupfer, M.

    1994-01-01

    In the last two classes of materials have been discovered which distinguish themselves due to a transition into the superconducting state at relatively high temperatures. These are the cuprate superconductors and the alkali metal doped fullerenes. In this work the electronic structure of representatives of these materials, undoped and Ca-doped YBa 2 Cu 4 O 8 and A 3 C 60 (A=K, Rb), has been investigated using electron energy-loss spectroscopy and photoemission spectroscopy. (orig.) [de

  1. High resolution electron microscopy and electron diffraction of YBa2Cu3O(7-x)

    International Nuclear Information System (INIS)

    Krakow, W.; Shaw, T.M.

    1988-01-01

    Experimental high resolution electron micrographs and computer simulation experiments have been used to evaluate the visibility of the atomic constituents of YBa 2 Cu 3 O(7-x). In practice, the detection of oxygen has not been possible in contradiction to that predicted by modelling of perfect crystalline material. Preliminary computer experiments of the electron diffraction patterns when oxygen vacancies are introduced on the Cu-O sheets separating Ba layers show the diffuse streaks characteristic of short range ordering. 7 references

  2. High-Throughput Printing Process for Flexible Electronics

    Science.gov (United States)

    Hyun, Woo Jin

    Printed electronics is an emerging field for manufacturing electronic devices with low cost and minimal material waste for a variety of applications including displays, distributed sensing, smart packaging, and energy management. Moreover, its compatibility with roll-to-roll production formats and flexible substrates is desirable for continuous, high-throughput production of flexible electronics. Despite the promise, however, the roll-to-roll production of printed electronics is quite challenging due to web movement hindering accurate ink registration and high-fidelity printing. In this talk, I will present a promising strategy for roll-to-roll production using a novel printing process that we term SCALE (Self-aligned Capillarity-Assisted Lithography for Electronics). By utilizing capillarity of liquid inks on nano/micro-structured substrates, the SCALE process facilitates high-resolution and self-aligned patterning of electrically functional inks with greatly improved printing tolerance. I will show the fabrication of key building blocks (e.g. transistor, resistor, capacitor) for electronic circuits using the SCALE process on plastics.

  3. Frontend electronics for high-precision single photo-electron timing using FPGA-TDCs

    Energy Technology Data Exchange (ETDEWEB)

    Cardinali, M., E-mail: cardinal@kph.uni-mainz.de [Institut für Kernphysik, Johannes Gutenberg-University Mainz, Mainz (Germany); Helmholtz Institut Mainz, Mainz (Germany); Dzyhgadlo, R.; Gerhardt, A.; Götzen, K.; Hohler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Ugur, C.; Zühlsdorf, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); Dodokhov, V.Kh. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Britting, A. [Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); and others

    2014-12-01

    The next generation of high-luminosity experiments requires excellent particle identification detectors which calls for Imaging Cherenkov counters with fast electronics to cope with the expected hit rates. A Barrel DIRC will be used in the central region of the Target Spectrometer of the planned PANDA experiment at FAIR. A single photo-electron timing resolution of better than 100 ps is required by the Barrel DIRC to disentangle the complicated patterns created on the image plane. R and D studies have been performed to provide a design based on the TRB3 readout using FPGA-TDCs with a precision better than 20 ps RMS and custom frontend electronics with high-bandwidth pre-amplifiers and fast discriminators. The discriminators also provide time-over-threshold information thus enabling walk corrections to improve the timing resolution. Two types of frontend electronics cards optimised for reading out 64-channel PHOTONIS Planacon MCP-PMTs were tested: one based on the NINO ASIC and the other, called PADIWA, on FPGA discriminators. Promising results were obtained in a full characterisation using a fast laser setup and in a test experiment at MAMI, Mainz, with a small scale DIRC prototype. - Highlights: • Frontend electronics for Cherenkov detectors have been developed. • FPGA-TDCs have been used for high precision timing. • Time over threshold has been utilised for walk correction. • Single photo-electron timing resolution less than 100 ps has been achieved.

  4. The ZTF Bright Transient Survey

    Science.gov (United States)

    Fremling, C.; Sharma, Y.; Kulkarni, S. R.; Miller, A. A.; Taggart, K.; Perley, D. A.; Gooba, A.

    2018-06-01

    As a supplement to the Zwicky Transient Facility (ZTF; ATel #11266) public alerts (ATel #11685) we plan to report (following ATel #11615) bright probable supernovae identified in the raw alert stream from the ZTF Northern Sky Survey ("Celestial Cinematography"; see Bellm & Kulkarni, 2017, Nature Astronomy 1, 71) to the Transient Name Server (https://wis-tns.weizmann.ac.il) on a daily basis; the ZTF Bright Transient Survey (BTS; see Kulkarni et al., 2018; arXiv:1710.04223).

  5. Electronics and triggering challenges for the CMS High Granularity Calorimeter

    Science.gov (United States)

    Lobanov, A.

    2018-02-01

    The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0.2 fC-10 pC), low noise (~2000 e- to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (~20 mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing the data from the HGCAL imposes equally large challenges on the off-detector electronics, both for the hardware and incorporated algorithms. We present an overview of the complete electronics architecture, as well as the performance of prototype components and algorithms.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-01-01

    The Fusion-FEM experiment, a high-power, electrostatic free-electron maser being built at the FOM-Institute for Plasma Physics 'Rijnhuizen', is operated at various frequencies. So far, experiments were done without a depressed collector, and the pulse length was limited to 12 {mu}s. Nevertheless, many aspects of generation of mm-wave power have been explored, such as the dependency on the electron beam energy and beam current, and cavity settings such as the feedback coefficient. An output power of 730 kW at 206 GHz is generated with a 7.2 A, 1.77 MeV electron beam, and 360 kW at 167 GHz is generated with a 7.4 A, 1.61 MeV electron beam. It is shown experimentally and by simulations that, depending on the electron beam energy, the FEM can operate in single-frequency regime. The next step of the FEM experiment is to reach a pulse length of 100 ms. The major part of the beam line, the high voltage systems, and the collector have been completed. The undulator and mm-wave cavity are now at high voltage (2 MV). The new mm-wave transmission line, which transports the mm-wave output power from the high-voltage terminal to ground and outside the pressure tank, has been tested at low power.

  7. High electron beam dosimetry using ZrO2

    International Nuclear Information System (INIS)

    Lueza M, F.; Rivera M, T.; Azorin N, J.; Garcia H, M.

    2009-10-01

    This paper reports the experimental results of studying the thermoluminescent (Tl) properties of ZrO 2 powder embedded in polytetrafluorethylene (PTFE) exposed to high energy electron beam from linear accelerators (Linac). Structural and morphological characteristics were also reported. Irradiations were conducted using high energy electrons beams in the range from 2 to 18 MeV. Pellets of ZrO 2 +PTFE were produced using polycrystalline powder grown by the precipitation method. These pellets presented a Tl glow curve exhibiting an intense glow peak centered at around 235 C. Tl response as a function of high electron absorbed dose was linear in the range from 2 to 30 Gy. Repeatability determined by exposing a set of pellets repeatedly to the same electron absorbed dose was 0.5%. Fading along 30 days was about 50%. Then, results obtained in this study suggest than ZrO 2 +PTFE pellets could be used for high energy electron beam dosimetry provided fading correction is accounted for. (Author)

  8. Evaporation of carbon using electrons of a high density plasma

    International Nuclear Information System (INIS)

    Muhl, S.; Camps, E.; Escobar A, L.; Garcia E, J.L.; Olea, O.

    1999-01-01

    The high density plasmas are used frequently in the preparation of thin films or surface modification, for example to nitridation. In these processes, are used mainly the ions and the neutrals which compose the plasma. However, the electrons present in the plasma are not used, except in the case of chemical reactions induced by collisions, although the electron bombardment usually get hot the work piece. Through the adequate polarization of a conductor material, it is possible to extract electrons from a high density plasma at low pressure, that could be gotten the evaporation of this material. As result of the interaction between the plasma and the electron flux with the vapor produced, this last will be ionized. In this work, it is reported the use of this novelty arrangement to prepare carbon thin films using a high density argon plasma and a high purity graphite bar as material to evaporate. It has been used substrates outside plasma and immersed in the plasma. Also it has been reported the plasma characteristics (temperature and electron density, energy and ions flux), parameters of the deposit process (deposit rate and ion/neutral rate) as well as the properties of the films obtained (IR absorption spectra and UV/Vis, elemental analysis, hardness and refractive index. (Author)

  9. 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.

  10. Preliminary investigations on high energy electron beam tomography

    Energy Technology Data Exchange (ETDEWEB)

    Baertling, Yves; Hoppe, Dietrich; Hampel, Uwe

    2010-12-15

    In computed tomography (CT) cross-sectional images of the attenuation distribution within a slice are created by scanning radiographic projections of an object with a rotating X-ray source detector compound and subsequent reconstruction of the images from these projection data on a computer. CT can be made very fast by employing a scanned electron beam instead of a mechanically moving X-ray source. Now this principle was extended towards high-energy electron beam tomography with an electrostatic accelerator. Therefore a dedicated experimental campaign was planned and carried out at the Budker Institute of Nuclear Physics (BINP), Novosibirsk. There we investigated the capabilities of BINP's accelerators as an electron beam generating and scanning unit of a potential high-energy electron beam tomography device. The setup based on a 1 MeV ELV-6 (BINP) electron accelerator and a single detector. Besides tomographic measurements with different phantoms, further experiments were carried out concerning the focal spot size and repeat accuracy of the electron beam as well as the detector's response time and signal to noise ratio. (orig.)

  11. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1997-11-01

    This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

  12. High-Energy Compton Scattering Light Sources

    CERN Document Server

    Hartemann, Fred V; Barty, C; Crane, John; Gibson, David J; Hartouni, E P; Tremaine, Aaron M

    2005-01-01

    No monochromatic, high-brightness, tunable light sources currently exist above 100 keV. Important applications that would benefit from such new hard x-ray sources include: nuclear resonance fluorescence spectroscopy, time-resolved positron annihilation spectroscopy, and MeV flash radiography. The peak brightness of Compton scattering light sources is derived for head-on collisions and found to scale with the electron beam brightness and the drive laser pulse energy. This gamma 2

  13. Bright and durable field emission source derived from refractory taylor cones

    Science.gov (United States)

    Hirsch, Gregory

    2016-12-20

    A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tip end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.

  14. Electron curing for high speed paper, film and foil converting

    International Nuclear Information System (INIS)

    Nablo, S.V.; Tripp, E.P.

    1979-01-01

    The status of self-shielded, compact electron processors for flexible web converting applications is reviewed. The uses of these units for a variety of laminating applications are described, with emphasis on the application techniques appropriate for low weight, (1 to 2 gm/m 2 ) 100% convertible adhesives. Performance data for electron cured adhesives with polyester/polyethylene systems is presented and compared with conventional urethane systems. The unique surface features of electron cured gravure coatings applied and cured at high speed are discussed, with reference to both paper and film substrates. An important advantage of electron curing of buried adhesive layers is the process quality control permitted by this 'all-electric' system. The performance characteristics of curing atmosphere control (inerting) for coatings are reviewed. Industrial experience with these processors has shown that effective inerting of coated flexible webs at speeds to 250 m/minute is both practical and economical. (author)

  15. Disinfection of wastewaters: high-energy electron vs gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, S [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Civil Engineering; Kurucz, C N; Waite, T D [Miami Univ., Coral Gables, FL (United States); Cooper, W J [Florida International Univ., Miami, FL (United States). Drinking Water Research Center

    1993-07-01

    A study was undertaken to examine the sensitivity of a wastewater population of coliphage, total coliforms and total flora present in raw sewage and secondary effluent after irradiating with similar doses delivered by a high-energy electron beam and [gamma]-radiation. The electron beam study was conducted on a large scale at the Virginia Key Wastewater Treatment Plant, Miami, Florida. The facility is equipped with a 1.5 MeV, 50 mA electron accelerator, with a wastewater flow rate of 8ls[sup -1]. Concurrent [gamma]-radiation studies were conducted at laboratory scale using a 5000 Ci, [sup 60]Co [gamma]-source. Three logs reduction of all three test organisms were observed at an electron beam dose of 500 krads, while at least four logs reduction were observed at the same dose utilizing the [gamma]'source. (Author).

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  17. Innovative electron-beam welding of high-melting metals

    International Nuclear Information System (INIS)

    Behr, W.; Reisgen, U.

    2007-01-01

    Since its establishment as nuclear research plant Juelich in the year 1956, the research centre Juelich (FZJ) is concerned with the material processing of special metals. Among those are, above all, the high-melting refractory metals niobium, molybdenum and tungsten. Electron beam welding has always been considered to be an innovative special welding method; in the FZJ, electron beam welding has, moreover, always been adapted to the increasing demands made by research partners and involved manufacturing and design sectors. From the manual equipment technology right up to highly modern multi-beam technique, the technically feasible for fundamental research has, this way, always been realised. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [de

  18. Simulation of electron displacement damage in a high voltage electron microscope

    International Nuclear Information System (INIS)

    Ono, Susumu; Kanaya, Koichi

    1979-01-01

    By applying the fundamental theory of the neutron cooling to the conservation law of energy and momentum, the threshold energies of incident electrons for displacing atoms are calculated and illustrated periodically for the atomic number. And the observable damage due to the secondary action of displaced atoms in the practical use of a high voltage electron microscope is described for several materials and accelerating voltages. The trajectories of incident electrons and displaced atoms in several materials are simulated by a Monte-Carlo method, using rigorous formulas of electron scattering events, i.e. elastic and inelastic scattering cross-sections, ionization loss and plasmon excitation. The simulation results are substantially agreement with experiments. (author)

  19. High luminosity electron-hadron collider eRHIC

    Energy Technology Data Exchange (ETDEWEB)

    Ptitsyn, V.; Aschenauer, E.; Bai, M.; Beebe-Wang, J.; Belomestnykh, S.; Ben-Zvi, I.; Blaskiewicz, M..; Calaga, R.; Chang, X.; Fedotov, A.; Gassner, D.; Hammons, L.; Hahn, H.; Hammons, L.; He, P.; Hao, Y.; Jackson, W.; Jain, A.; Johnson, E.C.; Kayran, D.; Kewisch, J.; Litvinenko, V.N.; Luo, Y.; Mahler, G.; McIntyre, G.; Meng, W.; Minty, M.; Parker, B.; Pikin, A.; Rao, T.; Roser, T.; Skaritka, J.; Sheehy, B.; Skaritka, J.; Tepikian, S.; Than, Y.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.; Wang, G.; Webb, S.; Wu, Q.; Xu, W.; Pozdeyev, E.; Tsentalovich, E.

    2011-03-28

    We present the design of a future high-energy high-luminosity electron-hadron collider at RHIC called eRHIC. We plan on adding 20 (potentially 30) GeV energy recovery linacs to accelerate and to collide polarized and unpolarized electrons with hadrons in RHIC. The center-of-mass energy of eRHIC will range from 30 to 200 GeV. The luminosity exceeding 10{sup 34} cm{sup -2} s{sup -1} can be achieved in eRHIC using the low-beta interaction region with a 10 mrad crab crossing. We report on the progress of important eRHIC R&D such as the high-current polarized electron source, the coherent electron cooling, ERL test facility and the compact magnets for recirculation passes. A natural staging scenario of step-by-step increases of the electron beam energy by building-up of eRHIC's SRF linacs is presented.

  20. High signal-to-noise ratio sensing with Shack–Hartmann wavefront sensor based on auto gain control of electron multiplying CCD

    International Nuclear Information System (INIS)

    Zhu Zhao-Yi; Li Da-Yu; Hu Li-Fa; Mu Quan-Quan; Yang Cheng-Liang; Cao Zhao-Liang; Xuan Li

    2016-01-01

    High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device (EMCCD) applied in the Shack–Hartmann wavefront sensor (S–H WFS) in adaptive optics (AO). However, when the brightness of the target changes in a large scale, the fixed electron multiplying (EM) gain will not be suited to the sensing limitation. Therefore an auto-gain-control method based on the brightness of light-spots array in S–H WFS is proposed in this paper. The control value is the average of the maximum signals of every light spot in an array, which has been demonstrated to be kept stable even under the influence of some noise and turbulence, and sensitive enough to the change of target brightness. A goal value is needed in the control process and it is predetermined based on the characters of EMCCD. Simulations and experiments have demonstrated that this auto-gain-control method is valid and robust, the sensing SNR reaches the maximum for the corresponding signal level, and especially is greatly improved for those dim targets from 6 to 4 magnitude in the visual band. (special topic)

  1. Electromagnetically induced transparency control in terahertz metasurfaces based on bright-bright mode coupling

    Science.gov (United States)

    Yahiaoui, R.; Burrow, J. A.; Mekonen, S. M.; Sarangan, A.; Mathews, J.; Agha, I.; Searles, T. A.

    2018-04-01

    We demonstrate a classical analog of electromagnetically induced transparency (EIT) in a highly flexible planar terahertz metamaterial (MM) comprised of three-gap split-ring resonators. The keys to achieve EIT in this system are the frequency detuning and hybridization processes between two bright modes coexisting in the same unit cell as opposed to bright-dark modes. We present experimental verification of two bright modes coupling for a terahertz EIT-MM in the context of numerical results and theoretical analysis based on a coupled Lorentz oscillator model. In addition, a hybrid variation of the EIT-MM is proposed and implemented numerically to dynamically tune the EIT window by incorporating photosensitive silicon pads in the split gap region of the resonators. As a result, this hybrid MM enables the active optical control of a transition from the on state (EIT mode) to the off state (dipole mode).

  2. High power electron accelerators for flue gas treatment

    International Nuclear Information System (INIS)

    Zimek, Z.

    2011-01-01

    Flue gas treatment process based on electron beam application for SO 2 and NO x removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

  3. High power electron accelerators for flue gas treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zimek, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2011-07-01

    Flue gas treatment process based on electron beam application for SO{sub 2} and NO{sub x} removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

  4. Record productions establish RF-driven sources as the standard for generating high-duty-factor, high-current H- beams for accelerators (Winner of the ICIS 2017 Brightness Award)

    Science.gov (United States)

    Stockli, Martin P.; Welton, Robert F.; Han, Baoxi

    2018-05-01

    The Spallation Neutron Source operates reliably at 1.2 MW and will gradually ramp to 1.4 MW. This paper briefly recalls some of the struggles when the unprecedented project was started and ramped to 1 MW over a 3½ year period. This was challenging, especially for the H- ion source and the low-energy beam transport system, which make up the H- injector. It took several more years to push the H- injector to the 1.4 MW requirements, and even longer to reach close to 100% injector availability. An additional breakthrough was the carefully staged, successful extension of the H- source service cycle so that disruptive source changes became rare events. More than 7 A.h of extracted H- ions have been demonstrated with a single source without maintenance, more than twice the single-source quantity of ions produced by any other high-current H- accelerator facility. Achieving the 1.4 MW requirements with close to 100% availability and record-breaking source service cycles were the basis for the 2017 Brightness Award.

  5. Thermalisation of high energy electrons and positrons in water vapour

    Science.gov (United States)

    Munoz, A.; Blanco, F.; Limao-Vieira, P.; Thorn, P. A.; Brunger, M. J.; Buckman, S. J.; Garcia, G.

    2008-07-01

    In this study we describe a method to simulate single electron tracks of electrons in molecular gases, particularly in water vapour, from relatively high energies, where Born (Inokuti 1971) approximation is supposed to be valid, down to thermal energies paying special attention to the low energy secondary electrons which are abundantly generated along the energy degradation procedure. Experimental electron scattering cross sections (Munoz et al. 2007) and energy loss spectra (Thorn et al. 2007) have been determined, where possible, to be used as input parameters of the simulating program. These experimental data have been complemented with optical potential calculation (Blanco and Garcia 2003) providing a complete set of interaction probability functions for each type of collision which could take place in the considered energy range: elastic, ionization, electronic excitation, vibrational and rotational excitation. From the simulated track structure (Munoz et al. 2005) information about energy deposition and radiation damage at the molecular level can be derived. A similar procedure is proposed to the study of single positron tracks in gases. Due to the lack of experimental data for positron interaction with molecules, especially for those related to energy loss and excitation cross sections, some distribution probability data have been derived from those of electron scattering by introducing positron characteristics as positroniun formation. Preliminary results for argon are presented discussing also the utility of the model to biomedical applications based on positron emitters.

  6. Consideration of Relativistic Dynamics in High-Energy Electron Coolers

    CERN Document Server

    Bruhwiler, David L

    2005-01-01

    A proposed electron cooler for RHIC would use ~55 MeV electrons to cool fully-ionized 100 GeV/nucleon gold ions.* At two locations in the collider ring, the electrons and ions will co-propagate for ~13 m, with velocities close to c and gamma>100. To lowest-order, one can Lorentz transform all physical quantities into the beam frame and calculate the dynamical friction forces assuming a nonrelativisitc, electrostatic plasma. However, we show that nonlinear space charge forces of the bunched electron beam on the ions must be calculated relativistically, because an electrostatic beam-frame calculation is not valid for such short interaction times. The validity of nonrelativistic friction force calculations must also be considered. Further, the transverse thermal velocities of the high-charge (~20 nC) electron bunch are large enough that some electrons have marginally relativistic velocities, even in the beam frame. Hence, we consider relativistic binary collisions – treating the model problem of ...

  7. Density-dependent electron transport and precise modeling of GaN high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, Sanyam, E-mail: bajaj.10@osu.edu; Shoron, Omor F.; Park, Pil Sung; Krishnamoorthy, Sriram; Akyol, Fatih; Hung, Ting-Hsiang [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Reza, Shahed; Chumbes, Eduardo M. [Raytheon Integrated Defense Systems, Andover, Massachusetts 01810 (United States); Khurgin, Jacob [Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Rajan, Siddharth [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Material Science and Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-10-12

    We report on the direct measurement of two-dimensional sheet charge density dependence of electron transport in AlGaN/GaN high electron mobility transistors (HEMTs). Pulsed IV measurements established increasing electron velocities with decreasing sheet charge densities, resulting in saturation velocity of 1.9 × 10{sup 7 }cm/s at a low sheet charge density of 7.8 × 10{sup 11 }cm{sup −2}. An optical phonon emission-based electron velocity model for GaN is also presented. It accommodates stimulated longitudinal optical (LO) phonon emission which clamps the electron velocity with strong electron-phonon interaction and long LO phonon lifetime in GaN. A comparison with the measured density-dependent saturation velocity shows that it captures the dependence rather well. Finally, the experimental result is applied in TCAD-based device simulator to predict DC and small signal characteristics of a reported GaN HEMT. Good agreement between the simulated and reported experimental results validated the measurement presented in this report and established accurate modeling of GaN HEMTs.

  8. Density-dependent electron transport and precise modeling of GaN high electron mobility transistors

    International Nuclear Information System (INIS)

    Bajaj, Sanyam; Shoron, Omor F.; Park, Pil Sung; Krishnamoorthy, Sriram; Akyol, Fatih; Hung, Ting-Hsiang; Reza, Shahed; Chumbes, Eduardo M.; Khurgin, Jacob; Rajan, Siddharth

    2015-01-01

    We report on the direct measurement of two-dimensional sheet charge density dependence of electron transport in AlGaN/GaN high electron mobility transistors (HEMTs). Pulsed IV measurements established increasing electron velocities with decreasing sheet charge densities, resulting in saturation velocity of 1.9 × 10 7  cm/s at a low sheet charge density of 7.8 × 10 11  cm −2 . An optical phonon emission-based electron velocity model for GaN is also presented. It accommodates stimulated longitudinal optical (LO) phonon emission which clamps the electron velocity with strong electron-phonon interaction and long LO phonon lifetime in GaN. A comparison with the measured density-dependent saturation velocity shows that it captures the dependence rather well. Finally, the experimental result is applied in TCAD-based device simulator to predict DC and small signal characteristics of a reported GaN HEMT. Good agreement between the simulated and reported experimental results validated the measurement presented in this report and established accurate modeling of GaN HEMTs

  9. Structure Identification in High-Resolution Transmission Electron Microscopic Images

    DEFF Research Database (Denmark)

    Vestergaard, Jacob Schack; Kling, Jens; Dahl, Anders Bjorholm

    2014-01-01

    A connection between microscopic structure and macroscopic properties is expected for almost all material systems. High-resolution transmission electron microscopy is a technique offering insight into the atomic structure, but the analysis of large image series can be time consuming. The present ...

  10. Ultra-stretchable Interconnects for high-density stretchable electronics

    NARCIS (Netherlands)

    Shafqat, S.; Hoefnagels, J.P.M.; Savov, A.; Joshi, S.; Dekker, R.; Geers, M.G.D.

    2017-01-01

    The exciting field of stretchable electronics (SE) promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects with micron-scale footprints, which calls for

  11. Scaling laws in high energy electron-nuclear processes

    International Nuclear Information System (INIS)

    Chemtob, M.

    1980-11-01

    We survey the parton model description of high momentum transfer electron scattering processes with nuclei. We discuss both nucleon and quark parton models and confront the patterns of scaling laws violations, induced by binding effects, in the former, and perturbative QCD effects, in the latter

  12. High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

    Science.gov (United States)

    Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

    2002-01-01

    It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

  13. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

    Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

  14. The highly reintegrative approach of electronic monitoring in the Netherlands

    NARCIS (Netherlands)

    Boone, M.M.; Kooij, van der M.; Rap, S.E.

    2017-01-01

    This contribution describes the way electronic monitoring (EM) is organized and implemented in the Netherlands. It will become clear that the situation in the Netherlands is characterized by, in particular, two features. The application of EM is highly interwoven with the Probation Service and its

  15. Analysis of electron cyclotron emission spectra of high electron temperature, supershot plasmas in TFTR

    International Nuclear Information System (INIS)

    Taylor, G.; Arunasalam, V.; Efthimion, P.C.; Grek, B.

    1993-01-01

    A primary objective of the TFTR program since 1986 has been the study and optimization of deuterium Supershot plasmas. These plasmas are predominantly heated by 90-110 keV neutral deuterium beams (P NBI /P OH >30), central ion temperatures are ∝30 keV and central electron temperatures from ECE (T ECE ) often exceed 10 keV. Central electron temperature data measured with a TV Thomson scattering (TVTS) system (T TVTS ) during the period 1987-1990 have been compared with data from three different ECE instruments on TFTR. Although T ECE ∝T TVTS for temperatures below 6 keV, there is a systematically increasing disagreement at higher electron temperatures, with T ECE ∝1.2 T TVTS for T TVTS in the range 9-10 keV. Recent theoretical work on the ECE radiation temperature of non-equilibrium plasmas indicates that for a bi-Maxwellian electron velocity distribution with a ratio of tail to bulk electron density η, a bulk temperature T b , and a hot tail temperature T h , the perpendicular ECE radiation temperature is given by T ECE ∝T b {1+η(T h /T b )}, for η ECE would be enhanced over T TVTS by a factor which depends on η and T h . This paper investigates whether the discrepancy between T TVTS and T ECE seen in TFTR Supershots at high electron temperatures is due to the presence of a hot electron tail component. The extraordinary mode ECE spectrum at the second, third and fourth harmonics is measured on the horizontal midplane by an absolutely calibrated ECE Michelson interferometer. This ECE spectrum is compared with the output from a time-independent transport code with relativistic opacity which solves the three-dimensional ECE radiation transport in a toroidally symmetric, two-dimensional geometry and uses measured electron density and temperature profiles from the TVTS system. (orig.)

  16. Development of an electron gun for high power CW electron linac (1). Beam experiment for basic performance of electron gun

    International Nuclear Information System (INIS)

    Yamazaki, Yoshio; Nomura, Masahiro; Komata, Tomoki

    1999-05-01

    Presently, the Beam Group of Oarai Engineering Center in Japan Nuclear Cycle Development Institute (JNC) completed the high power CW electron linac. Then we started full-scale beam experiments after the government permission for a radiation equipment had given last January. Measurements of basic performance for the mesh-grid type electron gun have been done to launch stable beam at 300 mA peak current downstream of the accelerator. These experiments disclosed to increase beam loss in the electron gun in some cases of voltage supplied the mesh-grid in spite of same beam current from gun. Consequently, we could find the best condition for mesh-grid voltage and heater current to supply stable beam at 300 mA peak current for accelerator study. (author)

  17. BANSHEE: High-voltage repetitively pulsed electron-beam driver

    International Nuclear Information System (INIS)

    VanHaaften, F.

    1992-01-01

    BANSHEE (Beam Accelerator for a New Source of High-Energy Electrons) this is a high-voltage modulator is used to produce a high-current relativistic electron beam for high-power microwave tube development. The goal of the BANSHEE research is first to achieve a voltage pulse of 700--750 kV with a 1-μs pulse width driving a load of ∼100 Ω, the pulse repetition frequency (PRF) of a few hertz. The ensuing goal is to increase the pulse amplitude to a level approaching 1 MV. We conducted tests using half the modulator with an output load of 200 Ω, up to a level of ∼650 kV at a PRF of 1 Hz and 525 kV at a PRF of 5 Hz. We then conducted additional testing using the complete system driving a load of ∼100 Ω

  18. High resolution electron attachment to molecules of atmospheric relevance

    International Nuclear Information System (INIS)

    Senn, G.

    2000-10-01

    This Ph.D. thesis is divided into three parts. The first is an introduction into the field of electron attachment. In the second part the experimental apparatus is described, and in the third part the results are presented. In the present thesis molecules were chosen for our investigations that are not only of academic interest but that also play an important role for applications or even the life on this planet. All the molecules studied in this work are of atmospheric relevance. NO, and OClO, are involved in the ozone depletion of the stratosphere. The D-layer of the ionosphere is an upper boundary of the ozone layer, therefore the interaction of the electrons from the D-layer with O 3 might play an important role for the chemistry in that part of the atmosphere. Especially the interaction of slow electrons (that will be present in the D-layer in large numbers) with ozone was emphasized in the present study. The production of O - and O 2 - by dissociative electron attachment to ozone was measured for incident electron energies between 0 and 10eV. A previously unobserved sharp structure was discovered in the formation of O - ions for electrons with zero kinetic energy. This additional cross section peak has important consequences for the role of ozone in the anion formation process in the ionosphere. Since OClO is a night time reservoir for chlorine atoms (Cl) and chlorine monoxide (ClO) both of which play a critical role in the depletion of the stratospheric ozone, we have studied negative ion formation following electron impact (0-10eV) to OClO. Despite its atmospheric relevance the mechanism of dissociative electron attachment (DEA) to NO is still a matter of controversy. DEA was studied at high energy resolution and with a kinetic-energy analysis of the O - fragment in two independent crossed electron-molecular-beam experiments. The DEA cross section exhibits a vertical onset near 7.45eV that corresponds to the energy threshold of the DEA channel O - ( 2 P

  19. Possibility of some radionuclides production using high energy electron Bremsstrahlung

    International Nuclear Information System (INIS)

    Balzhinnyam, N.; Belov, A.G.; Gehrbish, Sh; Maslov, O.D.; Shvetsov, V.N.; Ganbold, G.

    2008-01-01

    The method of some radionuclides production using high energy Bremsstrahlung of electron accelerators and determination of photonuclear reaction yield and specific activities for some radionuclides is described. Photonuclear reaction yield and specific activities for some radionuclides are determined for 117m Sn, 111 In and 195m Pt. Based on the experimental data obtained at low energy (E e- e- = 75 MeV) of the IREN facility (FLNR, JINR) at irradiation of high purity platinum and tin metals

  20. Inclusive quasielastic and deep inelastic electron scattering at high energies

    International Nuclear Information System (INIS)

    Day, D.B.

    1990-01-01

    With high electron energies a kinematic regime can be reached where it will be possible to separate quasielastic and deep inelastic scattering. We present a short description of these processes which dominate the inclusive spectrum. Using the highest momentum transfer data available to guide our estimates, we give the kinematic requirements and the cross sections expected. These results indicate that inclusive scattering at high q has a yet unfilled potential. 18 refs., 13 figs

  1. High brightness extreme ultraviolet (at 13.5 nm) emission from time-of-flight controlled discharges with coaxial fuel injection

    International Nuclear Information System (INIS)

    Hosokai, Tomonao; Horioka, Kazuhiko; Hotta, Eiki; Yokoyama, Takuma; Sato, Hiroto; Zhidkov, Alexei

    2008-01-01

    Extreme ultraviolet (EUV) emission from discharge produced plasma with the coaxial injection of fuel vapor (tin and lithium) produced by laser ablation is experimentally studied. Multiple plasma pinches preceding a strong and long recombination radiation of EUV are observed in the first half cycle of a sinusoidal discharge current. Due to the time-of-flight control type of the discharge, the shape of pinch radiation pulses is almost identical. With the coaxial injection of time-of-flight controlled discharges, the highest brightness of EUV emission (maximum extracted energy of 244.3 mJ/2π sr per pulse with the emitter size of ∼1x0.3 mm 2 in full width at half maximum) is provided with efficiency exceeding 2% of deposited energy into the plasma (or 1% of dissipated energy in the discharge) due to a much better matching with the optimal plasma parameters in the recombination regime and a decrease in the off-duty factor. Stability of emitting plasma of the repetitive pinches is essentially improved with use of a second laser pulse

  2. High-pressure electron-resonance studies of electronic, magnetic, and structural phase transitions. Progress report

    International Nuclear Information System (INIS)

    Pifer, J.H.; Croft, M.C.

    1983-01-01

    Research is described in development of a high-pressure electron-resonance probe capable of operating down to 1.5 0 K temperatures. The apparatus has been used to measure the EPR of a sample of DPPH at room temperature and zero pressure. EPR has been used to measure valence field instabilities in alloy systems. Studies have been done on metal-insulator transitions at high pressure, and are briefly described

  3. Survey on neutron production by electron beam from high power CW electron linear accelerator

    International Nuclear Information System (INIS)

    Toyama, S.

    1999-04-01

    In Japan Nuclear Cycle Development Institute, the development of high current CW electron linear accelerator is in progress. It is possible for an accelerator to produce neutrons by means of a spallation and photo nuclear reactions. Application of neutron beam produced by bremsstrahlung is one of ways of the utilization for high current electron accelerator. It is actual that many electron linear accelerators which maximum energy is higher than a few hundreds MeV are used as neutron sources. In this report, an estimate of neutron production is evaluated for high current CW electron linear accelerator. The estimate is carried out by 10 MeV beam which is maximum energy limited from the regulation and rather low for neutron production. Therefore, the estimate is also done by 17 and 35 MeV beam which is possible to be accelerated. Beryllium is considered as a target for lower electron energy in addition to Lead target for higher energy, because Beryllium has low threshold energy for neutron production. The evaluation is carried out in account of the target thickness optimized by the radiation length and neutron cross section reducing the energy loss for both of electron and neutron, so as to get the maximum number of neutrons. The result of the calculations shows neutron numbers 1.9 x 10 10 , 6.1 x 10 13 and 4.8 x 10 13 (n/s), respectively, for 10, 17, and 35 MeV with low duty. The thermal removal from the target is one of critical points. The additional shielding and cooling system is necessary in order to endure radiation. A comparison with other facilities are also carried out. The estimate of neutron numbers suggests the possibility to be applied for neutron radiography and measurement of nuclear data by means of Lead spectrometer, for example. (author)

  4. High speed electronic imaging application in aeroballistic research

    International Nuclear Information System (INIS)

    Brown, R.R.; Parker, J.R.

    1984-01-01

    Physical and temporal restrictions imposed by modern aeroballistics have pushed imaging technology to the point where special photoconductive surfaces and high-speed support electronics are dictated. Specifications for these devices can be formulated by a methodical analysis of critical parameters and how they interact. In terms of system theory, system transfer functions and state equations can be used in optimal coupling of devices to maximize system performance. Application of these methods to electronic imaging at the Eglin Aeroballistics Research Facility is described in this report. 7 references, 14 figures, 1 table

  5. The characterization of high quality multicrystalline silicon by the electron beam induced current method

    International Nuclear Information System (INIS)

    Chen, J; Sekiguchi, T; Nara, S; Yang, D

    2004-01-01

    Multicrystalline silicon (mc-Si) manufactured by a multi-stage solidification control casting method has been characterized by the electron beam induced current (EBIC) method. The average diffusion length of the ingot was over 250 μm, which was much longer than that of conventional mc-Si. The EBIC study revealed that the electrical activities of grain boundaries (GBs) varied with the ingot position due to the impurity contamination level. The main impurity detected was iron. The concentration of iron in the central position was much lower than that at the bottom and top positions. GBs in the central position showed no significant EBIC contrast at 300 K, suggesting low contamination level. GBs in the top and bottom positions, however, showed strong EBIC contrast at 300 K, suggesting high contamination level. At 100 K, a denuded zone with bright contrast developed around GBs in the top and bottom positions. The existence of the denuded zone suggested that impurities were gettered at the GBs. It was considered that the variation of the diffusion length in the ingot was related to the variation of recombination activities of GBs in the different positions, which mainly depended on the impurity contamination

  6. High-Energy Electron Beam Application to Air Pollutants Removal

    International Nuclear Information System (INIS)

    Ighigeanu, D.; Martin, D.; Manaila, E.; Craciun, G.; Calinescu, I.

    2009-01-01

    The advantage of electron beam (EB) process in pollutants removal is connected to its high efficiency to transfer high amount of energy directly into the matter under treatment. Disadvantage which is mostly related to high investment cost of accelerator may be effectively overcome in future as the result of use accelerator new developments. The potential use of medium to high-energy high power EB accelerators for air pollutants removal is demonstrated in [1]. The lower electrical efficiencies of accelerators with higher energies are partially compensated by the lower electron energy losses in the beam windows. In addition, accelerators with higher electron energies can provide higher beam powers with lower beam currents [1]. The total EB energy losses (backscattering, windows and in the intervening air space) are substantially lower with higher EB incident energy. The useful EB energy is under 50% for 0.5 MeV and about 95% above 3 MeV. In view of these arguments we decided to study the application of high energy EB for air pollutants removal. Two electron beam accelerators are available for our studies: electron linear accelerators ALIN-10 and ALID-7, built in the Electron Accelerator Laboratory, INFLPR, Bucharest, Romania. Both accelerators are of traveling-wave type, operating at a wavelength of 10 cm. They utilize tunable S-band magnetrons, EEV M 5125 type, delivering 2 MW of power in 4 μ pulses. The accelerating structure is a disk-loaded tube operating in the 2 mode. The optimum values of the EB peak current IEB and EB energy EEB to produce maximum output power PEB for a fixed pulse duration EB and repetition frequency fEB are as follows: for ALIN-10: EEB = 6.23 MeV; IEB =75 mA; PEB 164 W (fEB = 100 Hz, EB = 3.5 s) and for ALID-7: EEB 5.5 MeV; IEB = 130 mA; PEB = 670 W (fEB = 250 Hz, EB = 3.75 s). This paper presents a special designed installation, named SDI-1, and several representative results obtained by high energy EB application to SO 2 , NOx and VOCs

  7. High quality electron beams from a laser wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, S M; Issac, R C; Welsh, G H; Brunetti, E; Shanks, R P; Anania, M P; Cipiccia, S; Manahan, G G; Aniculaesei, C; Ersfeld, B; Islam, M R; Burgess, R T L; Vieux, G; Jaroszynski, D A [SUPA, Department of Physics, University of Strathclyde, Glasgow (United Kingdom); Gillespie, W A [SUPA, Division of Electronic Engineering and Physics, University of Dundee, Dundee (United Kingdom); MacLeod, A M [School of Computing and Creative Technologies, University of Abertay Dundee, Dundee (United Kingdom); Van der Geer, S B; De Loos, M J, E-mail: m.wiggins@phys.strath.ac.u [Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven (Netherlands)

    2010-12-15

    High quality electron beams have been produced in a laser-plasma accelerator driven by femtosecond laser pulses with a peak power of 26 TW. Electrons are produced with an energy up to 150 MeV from the 2 mm gas jet accelerator and the measured rms relative energy spread is less than 1%. Shot-to-shot stability in the central energy is 3%. Pepper-pot measurements have shown that the normalized transverse emittance is {approx}1{pi} mm mrad while the beam charge is in the range 2-10 pC. The generation of high quality electron beams is understood from simulations accounting for beam loading of the wakefield accelerating structure. Experiments and self-consistent simulations indicate that the beam peak current is several kiloamperes. Efficient transportation of the beam through an undulator is simulated and progress is being made towards the realization of a compact, high peak brilliance free-electron laser operating in the vacuum ultraviolet and soft x-ray wavelength ranges.

  8. A high-energy electron beam ion trap for production of high-charge high-Z ions

    International Nuclear Information System (INIS)

    Knapp, D.A.; Marrs, R.E.; Elliott, S.R.; Magee, E.W.; Zasadzinski, R.

    1993-01-01

    We have developed a new high-energy electron beam ion trap, the first laboratory source of low-energy, few-electron, high-Z ions. We describe the device and report measurements of its performance, including the electron beam diameter, current density and energy, and measurements of the ionization balance for several high-Z elements in the trap. This device opens up a wide range of possible experiments in atomic physics, plasma physics, and nuclear physics. (orig.)

  9. Bright betatronlike x rays from radiation pressure acceleration of a mass-limited foil target.

    Science.gov (United States)

    Yu, Tong-Pu; Pukhov, Alexander; Sheng, Zheng-Ming; Liu, Feng; Shvets, Gennady

    2013-01-25

    By using multidimensional particle-in-cell simulations, we study the electromagnetic emission from radiation pressure acceleration of ultrathin mass-limited foils. When a circularly polarized laser pulse irradiates the foil, the laser radiation pressure pushes the foil forward as a whole. The outer wings of the pulse continue to propagate and act as a natural undulator. Electrons move together with ions longitudinally but oscillate around the latter transversely, forming a self-organized helical electron bunch. When the electron oscillation frequency coincides with the laser frequency as witnessed by the electron, betatronlike resonance occurs. The emitted x rays by the resonant electrons have high brightness, short durations, and broad band ranges which may have diverse applications.

  10. Research of the Electron Cyclotron Emission with Vortex Property excited by high power high frequency Gyrotron

    Science.gov (United States)

    Goto, Yuki; Kubo, Shin; Tsujimura, Tohru; Takubo, Hidenori

    2017-10-01

    Recently, it has been shown that the radiation from a single electron in cyclotron motion has vortex property. Although the cyclotron emission exists universally in nature, the vortex property has not been featured because this property is normally cancelled out due to the randomness in gyro-phase of electrons and the development of detection of the vortex property has not been well motivated. In this research, we are developing a method to generate the vortex radiation from electrons in cyclotron motion with controlled gyro-phase. Electron that rotates around the uniform static magnetic field is accelerated by right-hand circular polarized (RHCP) radiation resonantly when the cyclotron frequency coincides with the applied RHCP radiation frequency. A large number of electrons can be coherently accelerated in gyro-phase by a RHCP high power radiation so that these electrons can radiate coherent emission with vortex feature. We will show that vortex radiation created by purely rotating electrons for the first time.

  11. Potential ceramics processing applications with high-energy electron beams

    International Nuclear Information System (INIS)

    Struve, K.W.; Turman, B.N.

    1993-01-01

    High-energy, high-current electron beams may offer unique features for processing of ceramics that are not available with any other heat source. These include the capability to instantaneously heat to several centimeters in depth, to preferentially deposit energy in dense, high-z materials, to process at atmospheric pressures in air or other gases, to have large control over heating volume and heating rate, and to have efficient energy conversion. At a recent workshop organized by the authors to explore opportunities for electron beam processing of ceramics, several applications were identified for further development. These were ceramic joining, fabrication of ceramic powders, and surface processing of ceramics. It may be possible to join ceramics by either electron-beam brazing or welding. Brazing with refractory metals might also be feasible. The primary concern for brazing is whether the braze material can wet to the ceramic when rapidly heated by an electron beam. Raw ceramic powders, such as silicon nitride and aluminum nitride, which are difficult to produce by conventional techniques, could possibly be produced by vaporizing metals in a nitrogen atmosphere. Experiments need to be done to verify that the vaporized metal can fully react with the nitrogen. By adjusting beam parameters, high-energy beams can be used to remove surface flaws which are often sites of fracture initiation. They can also be used for surface cleaning. The advantage of electron beams rather than ion beams for this application is that the heat deposition can be graded into the material. The authors will discuss the capabilities of beams from existing machines for these applications and discuss planned experiments

  12. Signature of electron-phonon interaction in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2011-09-01

    Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

  13. Research on high performance mirrors for free electron lasers

    International Nuclear Information System (INIS)

    Kitatani, Fumito

    1996-01-01

    For the stable functioning of free electron laser, high performance optical elements are required because of its characteristics. In particular in short wavelength free electron laser, since its gain is low, the optical elements having very high reflectivity are required. Also in free electron laser, since high energy noise light exists, the optical elements must have high optical breaking strength. At present in Power Reactor and Nuclear Fuel Development Corporation, the research for heightening the performance of dielectric multi-layer film elements for short wavelength is carried out. For manufacturing such high performance elements, it is necessary to develop the new materials for vapor deposition, new vapor deposition process, and the techniques of accurate substrate polishing and inspection. As the material that satisfies the requirements, there is diamond-like carbon (DLC) film, of which the properties are explained. As for the manufacture of the DLC films for short wavelength optics, the test equipment for forming the DLC films, the test of forming the DLC films, the change of the film quality due to gas conditions, discharge conditions and substrate materials, and the measurement of the optical breaking strength are reported. (K.I.)

  14. Final Report on DTRA Basic Research Project #BRCALL08-Per3-C-2-0006 "High-Z Non-Equilibrium Physics and Bright X-ray Sources with New Laser Targets"

    Energy Technology Data Exchange (ETDEWEB)

    Colvin, Jeffrey D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-06-01

    This project had two major goals. Final Goal: obtain spectrally resolved, absolutely calibrated x-ray emission data from uniquely uniform mm-scale near-critical-density high-Z plasmas not in local thermodynamic equilibrium (LTE) to benchmark modern detailed atomic physics models. Scientific significance: advance understanding of non-LTE atomic physics. Intermediate Goal: develop new nano-fabrication techniques to make suitable laser targets that form the required highly uniform non-LTE plasmas when illuminated by high-intensity laser light. Scientific significance: advance understanding of nano-science. The new knowledge will allow us to make x-ray sources that are bright at the photon energies of most interest for testing radiation hardening technologies, the spectral energy range where current x-ray sources are weak. All project goals were met.

  15. Room temperature synthesis of ultra-small, near-unity single-sized lead halide perovskite quantum dots with wide color emission tunability, high color purity and high brightness

    Science.gov (United States)

    Peng, Lucheng; Geng, Jing; Ai, Lisha; Zhang, Ying; Xie, Renguo; Yang, Wensheng

    2016-08-01

    Phosphor with extremely narrow emission line widths, high brightness, and wide color emission tunability in visible regions is required for display and lighting applications, yet none has been reported in the literature so far. In the present study, single-sized lead halide perovskite (APbX 3; A = CH3NH3 and Cs; X = Cl, Br, and I) nanocrystalline (NC) phosphors were achieved for the first time in a one-pot reaction at room temperature (25 °C). The size-dependent samples, which included four families of CsPbBr3 NCs and exhibited sharp excitonic absorption peaks and pure band gap emission, were directly obtained by simply varying the concentration of ligands. The continuity of the optical spectrum can be successively tuned over the entire UV-visible spectral region (360-610 nm) by preparing CsPbCl3, CsPbI3, and CsPb(Y/Br)3 (Y = Cl and I) NCs with the use of CsPbBr3 NCs as templates by anion exchange while maintaining the size of NCs and high quantum yields of up to 80%. Notably, an emission line width of 10-24 nm, which is completely consistent with that of their single particles, indicates the formation of single-sized NCs. The versatility of the synthetic strategy was validated by extending it to the synthesis of single-sized CH3NH3PbX 3 NCs by simply replacing the cesium precursor by the CH3NH3 X precursor.

  16. Patterning of high mobility electron gases at complex oxide interfaces

    DEFF Research Database (Denmark)

    Trier, Felix; Prawiroatmodjo, G. E. D. K.; von Soosten, Merlin

    2015-01-01

    Oxide interfaces provide an opportunity for electronics. However, patterning of electron gases at complex oxide interfaces is challenging. In particular, patterning of complex oxides while preserving a high electron mobility remains underexplored and inhibits the study of quantum mechanical effects...... of amorphous-LSM (a-LSM) thin films, which acts as a hard mask during subsequent depositions. Strikingly, the patterned modulation-doped interface shows electron mobilities up to ∼8 700 cm2/V s at 2 K, which is among the highest reported values for patterned conducting complex oxide interfaces that usually...... where extended electron mean free paths are paramount. This letter presents an effective patterning strategy of both the amorphous-LaAlO3/SrTiO3 (a-LAO/STO) and modulation-doped amorphous-LaAlO3/La7/8Sr1/8MnO3/SrTiO3 (a-LAO/LSM/STO) oxide interfaces. Our patterning is based on selective wet etching...

  17. High energy electron disinfection of sewage wastewater in flow systems

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, T; Arai, H; Hosono, M; Tokunaga, O; Machi, S [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Kondoh, M; Minemura, T; Nakao, A; Seike, Y [Sumitomo Heavy Industries Ltd., Tokyo (Japan)

    1990-01-01

    The disinfection of effluent municipal wastewaters by high-energy electrons in flow systems was studied using an experimental apparatus which has the maximum treatment capacity of 10.8 m{sup 3}/h. An electron accelerator with an accelerating voltage of 2 MV was used. The electron beam current was controlled to deliver the desired doses ranging from 0.05 to 1 kGy. Treatment times were in the range from 0.0022 to 0.051 s. Preliminary experiments with batch system using Petri dish of 100 ml showed that the effectiveness of electron irradiation on inactivation of coliforms was not influenced significantly by factors such as pH, SS, COD, DO and irradiation temperature. The dose required to produce 99.9% kill in the total population presented in wastewater were markedly affected by the thickness of water exposure to electron irradiation; that is, 0.39, 0.4 and 0.44 kGy for the depth of 5, 6 and 7 mm, respectively. The data obtained after a suitable correction for the doses due to the depth dose distribution showed no deviation from an experimental survival curve. Experiments with flow system indicated no measureable effect of the flow rate of wastewaters on the efficiency of disinfection in the range from 0.5 to 3.5 m/s. (author).

  18. Automated discrete electron tomography – Towards routine high-fidelity reconstruction of nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Zhuge, Xiaodong [Computational Imaging, Centrum Wiskunde & Informatica, Science park 123, 1098XG Amsterdam (Netherlands); Jinnai, Hiroshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Dunin-Borkowski, Rafal E.; Migunov, Vadim [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Bals, Sara [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Cool, Pegie [Laboratory of Adsorption and Catalysis, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Bons, Anton-Jan [European Technology Center, ExxonMobil Chemical Europe Inc., Hermeslaan 2, B-1831 Machelen (Belgium); Batenburg, Kees Joost [Computational Imaging, Centrum Wiskunde & Informatica, Science park 123, 1098XG Amsterdam (Netherlands)

    2017-04-15

    Electron tomography is an essential imaging technique for the investigation of morphology and 3D structure of nanomaterials. This method, however, suffers from well-known missing wedge artifacts due to a restricted tilt range, which limits the objectiveness, repeatability and efficiency of quantitative structural analysis. Discrete tomography represents one of the promising reconstruction techniques for materials science, potentially capable of delivering higher fidelity reconstructions by exploiting the prior knowledge of the limited number of material compositions in a specimen. However, the application of discrete tomography to practical datasets remains a difficult task due to the underlying challenging mathematical problem. In practice, it is often hard to obtain consistent reconstructions from experimental datasets. In addition, numerous parameters need to be tuned manually, which can lead to bias and non-repeatability. In this paper, we present the application of a new iterative reconstruction technique, named TVR-DART, for discrete electron tomography. The technique is capable of consistently delivering reconstructions with significantly reduced missing wedge artifacts for a variety of challenging data and imaging conditions, and can automatically estimate its key parameters. We describe the principles of the technique and apply it to datasets from three different types of samples acquired under diverse imaging modes. By further reducing the available tilt range and number of projections, we show that the proposed technique can still produce consistent reconstructions with minimized missing wedge artifacts. This new development promises to provide the electron microscopy community with an easy-to-use and robust tool for high-fidelity 3D characterization of nanomaterials. - Highlights: • Automated discrete electron tomography capable of consistently delivering reconstructions with significantly reduced missing wedge artifacts and requires significantly

  19. Automated discrete electron tomography – Towards routine high-fidelity reconstruction of nanomaterials

    International Nuclear Information System (INIS)

    Zhuge, Xiaodong; Jinnai, Hiroshi; Dunin-Borkowski, Rafal E.; Migunov, Vadim; Bals, Sara; Cool, Pegie; Bons, Anton-Jan; Batenburg, Kees Joost

    2017-01-01

    Electron tomography is an essential imaging technique for the investigation of morphology and 3D structure of nanomaterials. This method, however, suffers from well-known missing wedge artifacts due to a restricted tilt range, which limits the objectiveness, repeatability and efficiency of quantitative structural analysis. Discrete tomography represents one of the promising reconstruction techniques for materials science, potentially capable of delivering higher fidelity reconstructions by exploiting the prior knowledge of the limited number of material compositions in a specimen. However, the application of discrete tomography to practical datasets remains a difficult task due to the underlying challenging mathematical problem. In practice, it is often hard to obtain consistent reconstructions from experimental datasets. In addition, numerous parameters need to be tuned manually, which can lead to bias and non-repeatability. In this paper, we present the application of a new iterative reconstruction technique, named TVR-DART, for discrete electron tomography. The technique is capable of consistently delivering reconstructions with significantly reduced missing wedge artifacts for a variety of challenging data and imaging conditions, and can automatically estimate its key parameters. We describe the principles of the technique and apply it to datasets from three different types of samples acquired under diverse imaging modes. By further reducing the available tilt range and number of projections, we show that the proposed technique can still produce consistent reconstructions with minimized missing wedge artifacts. This new development promises to provide the electron microscopy community with an easy-to-use and robust tool for high-fidelity 3D characterization of nanomaterials. - Highlights: • Automated discrete electron tomography capable of consistently delivering reconstructions with significantly reduced missing wedge artifacts and requires significantly

  20. 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.

  1. High performance protection circuit for power electronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Tudoran, Cristian D., E-mail: cristian.tudoran@itim-cj.ro; Dădârlat, Dorin N.; Toşa, Nicoleta; Mişan, Ioan [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, PO 5 Box 700, 400293 Cluj-Napoca (Romania)

    2015-12-23

    In this paper we present a high performance protection circuit designed for the power electronics applications where the load currents can increase rapidly and exceed the maximum allowed values, like in the case of high frequency induction heating inverters or high frequency plasma generators. The protection circuit is based on a microcontroller and can be adapted for use on single-phase or three-phase power systems. Its versatility comes from the fact that the circuit can communicate with the protected system, having the role of a “sensor” or it can interrupt the power supply for protection, in this case functioning as an external, independent protection circuit.

  2. Frontend electronics for high-precision single photo-electron timing using FPGA-TDCs

    Science.gov (United States)

    Cardinali, M.; Dzyhgadlo, R.; Gerhardt, A.; Götzen, K.; Hohler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Ugur, C.; Zühlsdorf, M.; Dodokhov, V. Kh.; Britting, A.; Eyrich, W.; Lehmann, A.; Uhlig, F.; Düren, M.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Corell, O.; Ferretti Bondy, M. I.; Hoek, M.; Lauth, W.; Rosner, C.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

    2014-12-01

    The next generation of high-luminosity experiments requires excellent particle identification detectors which calls for Imaging Cherenkov counters with fast electronics to cope with the expected hit rates. A Barrel DIRC will be used in the central region of the Target Spectrometer of the planned PANDA experiment at FAIR. A single photo-electron timing resolution of better than 100 ps is required by the Barrel DIRC to disentangle the complicated patterns created on the image plane. R&D studies have been performed to provide a design based on the TRB3 readout using FPGA-TDCs with a precision better than 20 ps RMS and custom frontend electronics with high-bandwidth pre-amplifiers and fast discriminators. The discriminators also provide time-over-threshold information thus enabling walk corrections to improve the timing resolution. Two types of frontend electronics cards optimised for reading out 64-channel PHOTONIS Planacon MCP-PMTs were tested: one based on the NINO ASIC and the other, called PADIWA, on FPGA discriminators. Promising results were obtained in a full characterisation using a fast laser setup and in a test experiment at MAMI, Mainz, with a small scale DIRC prototype.

  3. APES: Acute Precipitating Electron Spectrometer - A High Time Resolution Monodirectional Magnetic Deflection Electron Spectrometer

    Science.gov (United States)

    Michell, R. G.; Samara, M.; Grubbs, G., II; Ogasawara, K.; Miller, G.; Trevino, J. A.; Webster, J.; Stange, J.

    2016-01-01

    We present a description of the Acute Precipitating Electron Spectrometer (APES) that was designed and built for the Ground-to-Rocket Electron Electrodynamics Correlative Experiment (GREECE) auroral sounding rocket mission. The purpose was to measure the precipitating electron spectrum with high time resolution, on the order of milliseconds. The trade-off made in order to achieve high time resolution was to limit the aperture to only one look direction. The energy selection was done by using a permanent magnet to separate the incoming electrons, such that the different energies would fall onto different regions of the microchannel plate and therefore be detected by different anodes. A rectangular microchannel plate (MCP) was used (15 mm x 100 mm), and there was a total of 50 discrete anodes under the MCP, each one 15 mm x 1.5 mm, with a 0.5 mm spacing between anodes. The target energy range of APES was 200 eV to 30 keV.

  4. High-energy electron beams for ceramic joining

    Science.gov (United States)

    Turman, Bob N.; Glass, S. J.; Halbleib, J. A.; Helmich, D. R.; Loehman, Ron E.; Clifford, Jerome R.

    1995-03-01

    Joining of structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for high temperature joining. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the ceramic. We have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 MPa have been measured. This strength is comparable to that reported in the literature for bonding silicon nitride (Si3N4) to molybdenum with copper-silver-titanium braze, but weaker than that reported for Si3N4 - Si3N4 with gold-nickel braze. The bonding mechanism appears to be formation of a thin silicide layer. Beam damage to the Si3N4 was also assessed.

  5. Feasibility of ceramic joining with high energy electron beams

    International Nuclear Information System (INIS)

    Turman, B.N.; Glass, S.J.; Halbleib, J.A.; Helmich, D.R.; Loehman, R.E.; Clifford, J.R.

    1995-01-01

    Joining structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for producing joints with high temperature capability. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the adjacent ceramic. The authors have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 NTa have been measured for Si 3 N 4 -Mo-Si 3 N 4 . These modest strengths are due to beam non-uniformity and the limited area of bonding. The bonding mechanism appears to be a thin silicide reaction layer. Si 3 N 4 -Si 3 N 4 joints with no metal layer were also produced, apparently bonded an yttrium apatite grain boundary phase

  6. Electronics and triggering challenges for the CMS High Granularity Calorimeter

    CERN Document Server

    Lobanov, Artur

    2017-01-01

    The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0-10 pC), low noise (~2000e- to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (~10mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing all the data from the HGCAL imposes equally large ch...

  7. 143 GHz BRIGHTNESS MEASUREMENTS OF URANUS, NEPTUNE, AND OTHER SECONDARY CALIBRATORS WITH BOLOCAM BETWEEN 2003 AND 2010

    International Nuclear Information System (INIS)

    Sayers, J.; Czakon, N. G.; Golwala, S. R.

    2012-01-01

    Bolocam began collecting science data in 2003 as the long-wavelength imaging camera at the Caltech Submillimeter Observatory. The planets, along with a handful of secondary calibrators, have been used to determine the flux calibration for all of the data collected with Bolocam. Uranus and Neptune stand out as the only two planets that are bright enough to be seen with high signal-to-noise in short integrations without saturating the standard Bolocam readout electronics. By analyzing all of the 143 GHz observations made with Bolocam between 2003 and 2010, we find that the brightness ratio of Uranus to Neptune is 1.027 ± 0.006, with no evidence for any variations over that period. Including previously published results at ≅ 150 GHz, we find a brightness ratio of 1.029 ± 0.006 with no evidence for time variability over the period 1983-2010. Additionally, we find no evidence for time variability in the brightness ratio of either Uranus or Neptune to the ultracompact H II region G34.3 or the protostellar source NGC 2071IR. Using recently published Wilkinson Microwave Anisotropy Probe results we constrain the absolute 143 GHz brightness of both Uranus and Neptune to ≅ 3%. Finally, we present ≅ 3% absolute 143 GHz peak flux density values for the ultracompact H II regions G34.3 and K3-50A and the protostellar source NGC 2071IR.

  8. DEMONSTRATION BULLETIN: HIGH VOLTAGE ELECTRON BEAM TECHNOLOGY - HIGH VOLTAGE ENVIRONMENTAL APPLICATIONS, INC.

    Science.gov (United States)

    The high energy electron beam irradiation technology is a low temperature method for destroying complex mixtures of hazardous organic chemicals in solutions containing solids. The system consists of a computer-automated, portable electron beam accelerator and a delivery system. T...

  9. Measurement of few-electron uranium ions on a high-energy electron beam ion trap

    International Nuclear Information System (INIS)

    Beiersdorfer, P.

    1994-01-01

    The high-energy electron beam ion trap, dubbed Super-EBIT, was used to produce, trap, and excite uranium ions as highly charged as fully stripped U 92+ . The production of such highly charged ions was indicated by the x-ray emission observed with high-purity Ge detectors. Moreover, high-resolution Bragg crystal spectromters were used to analyze the x-ray emission, including a detailed measurement of both the 2s 1/2 -2p 3/2 electric dipole and 2p 1/2 -2p 3/2 magnetic dipole transitions. Unlike in ion accelerators, where the uranium ions move at relativistic speeds, the ions in this trap are stationary. Thus very precise measurements of the transition energies could be made, and the QED contribution to the transition energies could be measured within less than 1 %. Details of the production of these highly charged ions and their measurement is given

  10. Development of the high-power THz spectroscopy and imaging systems on the basis of an S-band compact electron LINAC

    International Nuclear Information System (INIS)

    Kuroda, R.; Taira, Y.; Tanaka, M.; Toyokawa, H.; Yamada, K.; Kumaki, M.; Tachibana, M.; Sakaue, K.; Washio, M.

    2014-01-01

    The high-power terahertz time-domain spectroscopy (THz-TDS) and imaging systems have been developed on the basis of an S-band compact electron linac at AIST. Such high-power THz source is strongly expected for inspection of dangerous materials in the homeland security field. The high-power THz radiations are generated in two methods with the high-brightness ultra-short electron bunch. One is THz coherent synchrotron radiation (THz-CSR) for THz imaging applications. The other is THz coherent transition radiation (THz-CTR) for the THz spectroscopy. The THz-CTR time-domain spectroscopy (TDS) has been constructed with the EO sampling method and demonstrated in freq. range between 0.1-2 THz. The absorption measurements of drug samples have been successfully performed in atmosphere. In this symposium, we will describe details of the THz-CTR-TDS and imaging experiments and a future plan of the THz applications. (author)

  11. On the possibility of obtaining high-energy polarized electrons on Yerevan synchrotron

    International Nuclear Information System (INIS)

    Melikyan, R.A.

    1975-01-01

    A possibility of producing high-energy polarized electrons on the Yerevan synchrotron is discussed. A review of a number of low-energy polarized electron sources and of some of experiments with high-energy polarized electrons is given

  12. Harmonic operation of high gain harmonic generation free electron laser

    International Nuclear Information System (INIS)

    Deng Haixiao; Chinese Academy of Sciences, Beijing; Dai Zhimin

    2008-01-01

    In high gain harmonic generation (HGHG) free electron laser (FEL), with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation (HO) mode. In this paper, we investigate HO of HGHG FEL. Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy. (authors)

  13. 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

  14. Laboratory Astrophysics Using High Energy Density Photon and Electron Beams

    CERN Document Server

    Bingham, Robert

    2005-01-01

    The development of intense laser and particle beams has opened up new opportunities to study high energy density astrophysical processes in the Laboratory. With even higher laser intensities possible in the near future vacuum polarization processes such as photon - photon scattering with or without large magnetic fields may also be experimentally observed. In this talk I will review the status of laboratory experiments using intense beans to investigate extreme astrophysical phenomena such as supernovae explosions, gamma x-ray bursts, ultra-high energy cosmic accelerators etc. Just as intense photon or electron beams can excite relativistic electron plasma waves or wakefields used in plasma acceleration, intense neutrino beams from type II supernovae can also excite wakefields or plasma waves. Other instabilities driven by intense beams relevant to perhaps x-ray bursts is the Weibel instability. Simulation results of extreme processes will also be presented.

  15. High-resolution observation by double-biprism electron holography

    International Nuclear Information System (INIS)

    Harada, Ken; Tonomura, Akira; Matsuda, Tsuyoshi; Akashi, Tetsuya; Togawa, Yoshihiko

    2004-01-01

    High-resolution electron holography has been achieved by using a double-biprism interferometer implemented on a 1 MV field emission electron microscope. The interferometer was installed behind the first magnifying lens to narrow carrier fringes and thus enabled complete separation of sideband Fourier spectrum from center band in reconstruction process. Holograms of Au fine particles and single-crystalline thin films with the finest fringe spacing of 4.2 pm were recorded and reconstructed. The overall holography system including the reconstruction process performed well for holograms in which carrier fringes had a spacing of around 10 pm. High-resolution lattice images of the amplitude and phase were clearly reconstructed without mixing of the center band and sideband information. Additionally, entire holograms were recorded without Fresnel fringes normally generated by the filament electrode of the biprism, and the holograms were thus reconstructed without the artifacts caused by Fresnel fringes

  16. Precision crystal alignment for high-resolution electron microscope imaging

    International Nuclear Information System (INIS)

    Wood, G.J.; Beeching, M.J.

    1990-01-01

    One of the more difficult tasks involved in obtaining quality high-resolution electron micrographs is the precise alignment of a specimen into the required zone. The current accepted procedure, which involves changing to diffraction mode and searching for symmetric point diffraction pattern, is insensitive to small amounts of misalignment and at best qualitative. On-line analysis of the fourier space representation of the image, both for determining and correcting crystal tilt, is investigated. 8 refs., 42 figs

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  18. Parity nonconservation in polarized electron scattering at high energies

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1979-10-01

    Recent observations of parity violation in inelastic scattering of electrons at high energy is discussed with reference to the process e(polarized) + D(unpolarized) → e + X. The kinetics of this process, the idealized case of scattering from free quark targets, experimental techniques and results, and relations to atomic physics of parity violation in bismuth and thallium atoms with a model independent analysis. 17 references

  19. Environmental high resolution electron microscopy and applications to chemical science

    OpenAIRE

    Boyes, Edward; Gai, Pratibha

    2017-01-01

    An environmental cell high resolution electron microscope (EHREM) has been developed for in situ studies of dynamic chemical reactions on the atomic scale. It allows access to metastable intermediate phases of catalysts and to sequences of reversible microstructural and chemical development associated with the activation, deactivation and poisoning of a catalyst. Materials transported through air can be restored or recreated and samples damaged, e.g. by dehydration, by the usual vacuum enviro...

  20. Kinase detection with gallium nitride based high electron mobility transistors.

    Science.gov (United States)

    Makowski, Matthew S; Bryan, Isaac; Sitar, Zlatko; Arellano, Consuelo; Xie, Jinqiao; Collazo, Ramon; Ivanisevic, Albena

    2013-07-01

    A label-free kinase detection system was fabricated by the adsorption of gold nanoparticles functionalized with kinase inhibitor onto AlGaN/GaN high electron mobility transistors (HEMTs). The HEMTs were operated near threshold voltage due to the greatest sensitivity in this operational region. The Au NP/HEMT biosensor system electrically detected 1 pM SRC kinase in ionic solutions. These results are pertinent to drug development applications associated with kinase sensing.