National Library of Energy BETA

Sample records for high intensity laser

  1. Radiation Dose Measurement for High-Intensity Laser Interactions...

    Office of Scientific and Technical Information (OSTI)

    Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC Citation Details In-Document Search Title: Radiation Dose Measurement for High-Intensity...

  2. Quantum Vacuum Experiments Using High Intensity Lasers

    E-Print Network [OSTI]

    Mattias Marklund; Joakim Lundin

    2009-04-02

    The quantum vacuum constitutes a fascinating medium of study, in particular since near-future laser facilities will be able to probe the nonlinear nature of this vacuum. There has been a large number of proposed tests of the low-energy, high intensity regime of quantum electrodynamics (QED) where the nonlinear aspects of the electromagnetic vacuum comes into play, and we will here give a short description of some of these. Such studies can shed light, not only on the validity of QED, but also on certain aspects of nonperturbative effects, and thus also give insights for quantum field theories in general.

  3. The investigation of high intensity laser driven micro neutron sources

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    , access to high temperature states of mat- ter capable of thermonuclear fusion and/or the effi- cientThe investigation of high intensity laser driven micro neutron sources for fusion materials. The application of fast pulse, high intensity lasers to drive low cost DT point neutron sources for fusion

  4. Fusion neutron yield from high intensity laser-cluster interaction

    SciTech Connect (OSTI)

    Davis, J.; Petrov, G.M.; Velikovich, A.L. [Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)

    2006-06-15

    The fusion neutron yield from a compact neutron source is studied. Laser-irradiated deuterium clusters serve as a precursor of high-energy deuterium ions, which react with the walls of a fusion reaction chamber and produce copious amounts of neutrons in fusion reactions. The explosion of deuterium clusters with initial radius of 50-200 A irradiated by a subpicosecond laser with intensity of 10{sup 16} W/cm{sup 2} is examined theoretically. We studied the conversion efficiency of laser energy to ion kinetic energy, the mean and maximum ion kinetic energy, and ion energy distribution function by a molecular dynamics model. A yield of {approx}10{sup 5}-10{sup 6} neutrons/J is obtainable for a peak laser intensity of 10{sup 16}-10{sup 17} W/cm{sup 2} and clusters with an initial radius of 200-400 A.

  5. Laser enhanced high-intensity focused ultrasound thrombolysis: An in vitro study

    E-Print Network [OSTI]

    Cui, Huizhong; Yang, Xinmai

    2013-01-17

    Laser-enhanced thrombolysis by high intensity focused ultrasound (HIFU) treatment was studied in vitro with bovine blood clots. To achieve laser-enhanced thrombolysis, laser light was employed to illuminate the sample concurrently with HIFU...

  6. Present and future perspectives for high energy density physics with intense heavy ion and laser beams

    E-Print Network [OSTI]

    , Germany! accelerator facilities, together with two high energy laser systems: petawatt high energy laserPresent and future perspectives for high energy density physics with intense heavy ion and laser!, Plasmaphysik, Darmstadt, Germany 2 Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt

  7. Can we detect "Unruh radiation" in the high intensity lasers?

    E-Print Network [OSTI]

    Satoshi Iso; Yasuhiro Yamamoto; Sen Zhang

    2011-02-23

    An accelerated particle sees the Minkowski vacuum as thermally excited, which is called the Unruh effect. Due to an interaction with the thermal bath, the particle moves stochastically like the Brownian motion in a heat bath. It has been discussed that the accelerated charged particle may emit extra radiation (the Unruh radiation) besides the Larmor radiation, and experiments are under planning to detect such radiation by using ultrahigh intensity lasers. There are, however, counterarguments that the radiation is canceled by an interference effect between the vacuum fluctuation and the radiation from the fluctuating motion. In this reports, we review our recent analysis on the issue of the Unruh radiation. In this report, we particularly consider the thermalization of an accelerated particle in the scalar QED, and derive the relaxation time of the thermalization.

  8. Investigation of long-period fiber gratings induced by high-intensity femtosecond UV laser pulses

    E-Print Network [OSTI]

    Nikogosyan, David N.

    efficiency with that for other existing meth- ods of recording. We studied the temperature sensing properties changes in the fiber core induced by thermal heating, were developed. They include the use of a CO2 laserInvestigation of long-period fiber gratings induced by high-intensity femtosecond UV laser pulses

  9. Limitations on the attainable intensity of high power lasers

    E-Print Network [OSTI]

    A. M. Fedotov; N. B. Narozhny; G. Mourou; G. Korn

    2010-04-29

    It is shown that even a single $e^-e^+$ pair created by a super strong laser field in vacuum would cause development of an avalanche-like QED cascade which rapidly depletes the incoming laser pulse. This confirms the old N. Bohr conjecture that the electric field of the critical QED strength $E_S=m^2c^3/e\\hbar$ could never be created.

  10. Extension of high-order harmonic generation cutoff via coherent control of intense few-cycle chirped laser pulses

    E-Print Network [OSTI]

    Carrera, Juan J.; Chu, Shih-I

    2007-03-16

    We present an ab initio quantum investigation of the high-order harmonic generation (HHG) cutoff extension using intense few-cycle chirped laser pulses. For a few-cycle chirped driving laser pulse, it is shown that significant ...

  11. High-intensity laser-driven proton acceleration enhancement from hydrogen containing ultrathin targets

    SciTech Connect (OSTI)

    Dollar, F.; Reed, S. A.; Matsuoka, T.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; McGuffey, C.; Rousseau, P.; Thomas, A. G. R.; Willingale, L.; Yanovsky, V.; Krushelnick, K.; Maksimchuk, A.; Litzenberg, D. W.

    2013-09-30

    Laser driven proton acceleration experiments from micron and submicron thick targets using high intensity (2 × 10{sup 21} W/cm{sup 2}), high contrast (10{sup ?15}) laser pulses show an enhancement of maximum energy when hydrogen containing targets were used instead of non-hydrogen containing. In our experiments, using thin (<1?m) plastic foil targets resulted in maximum proton energies that were consistently 20%–100% higher than when equivalent thickness inorganic targets, including Si{sub 3}N{sub 4} and Al, were used. Proton energies up to 20 MeV were measured with a flux of 10{sup 7} protons/MeV/sr.

  12. Observations of the filamentation of high-intensity laser-produced electron beams

    SciTech Connect (OSTI)

    Wei, M.S.; Beg, F.N.; Dangor, A.E.; Gopal, A.; Tatarakis, M.; Krushelnick, K. [Blackett Laboratory, Imperial College London SW7 2BZ (United Kingdom); Clark, E.L.; Evans, R.G. [Blackett Laboratory, Imperial College London SW7 2BZ (United Kingdom); Plasma Physics Department, AWE plc, Aldermaston, Reading RG7 4PR (United Kingdom); Ledingham, K.W.D. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Plasma Physics Department, AWE plc, Aldermaston, Reading RG7 4PR (United Kingdom); McKenna, P. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Norreys, P.A. [Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Oxon OX11 OQX (United Kingdom); Zepf, M. [Department of Physics, The Queen's University, University Road, Belfast BT7 1NN (United Kingdom)

    2004-11-01

    Filamented electron beams have been observed to be emitted from the rear of thin solid targets irradiated by a high-intensity short-pulse laser when there is low-density plasma present at the back of the target. These observations are consistent with a laser-generated beam of relativistic electrons propagating through the target, which is subsequently fragmented by a Weibel-like instability in the low-density plasma at the rear. These measurements are in agreement with particle-in-cell simulations and theory, since the filamentation instability is predicted to be dramatically enhanced when the electron beam density approaches that of the background plasma.

  13. Electromagnetic cascade in high energy electron, positron, and photon interactions with intense laser pulses

    E-Print Network [OSTI]

    S. S. Bulanov; C. B. Schroeder; E. Esarey; W. P. Leemans

    2013-06-05

    The interaction of high energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when 3D effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high energy e-beam interacting with a counter-streaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.

  14. Characterization of the fast electrons distribution produced in a high intensity laser target interaction

    SciTech Connect (OSTI)

    Westover, B.; Lawrence Livermore National Laboratory, Livermore, California 94550 ; Chen, C. D.; Patel, P. K.; McLean, H.; Beg, F. N.

    2014-03-15

    Experiments on the Titan laser (?150?J, 0.7 ps, 2 × 10{sup 20} W cm{sup ?2}) at the Lawrence Livermore National Laboratory were carried out in order to study the properties of fast electrons produced by high-intensity, short pulse laser interacting with matter under conditions relevant to Fast Ignition. Bremsstrahlung x-rays produced by these fast electrons were measured by a set of compact filter-stack based x-ray detectors placed at three angles with respect to the target. The measured bremsstrahlung signal allows a characterization of the fast electron beam spectrum, conversion efficiency of laser energy into fast electron kinetic energy and angular distribution. A Monte Carlo code Integrated Tiger Series was used to model the bremsstrahlung signal and infer a laser to fast electron conversion efficiency of 30%, an electron slope temperature of about 2.2?MeV, and a mean divergence angle of 39°. Simulations were also performed with the hybrid transport code ZUMA which includes fields in the target. In this case, a conversion efficiency of laser energy to fast electron energy of 34% and a slope temperature between 1.5?MeV and 4?MeV depending on the angle between the target normal direction and the measuring spectrometer are found. The observed temperature of the bremsstrahlung spectrum, and therefore the inferred electron spectrum are found to be angle dependent.

  15. Propagation and absorption of high-intensity femtosecond laser radiation in diamond

    SciTech Connect (OSTI)

    Kononenko, V V; Konov, V I; Gololobov, V M; Zavedeev, E V [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2014-12-31

    Femtosecond interferometry has been used to experimentally study the photoexcitation of the electron subsystem of diamond exposed to femtosecond laser pulses of intensity 10{sup 11} to 10{sup 14} W cm{sup -2}. The carrier concentration has been determined as a function of incident intensity for three harmonics of a Ti : sapphire laser (800, 400 and 266 nm). The results demonstrate that, in a wide range of laser fluences (up to those resulting in surface and bulk graphitisation), a well-defined multiphoton absorption prevails. We have estimated nonlinear absorption coefficients for pulsed radiation at ? = 800 nm (four-photon transition) and at 400 and 266 nm (indirect and direct two-photon transitions, respectively). It has also been shown that, at any considerable path length of a femtosecond pulse in diamond (tens of microns or longer), the laser beam experiences a severe nonlinear transformation, determining the amount of energy absorbed by the lattice, which is important for the development of technology for diamond photostructuring by ultrashort pulses. The competition between wave packet self-focusing and the plasma defocusing effect is examined as a major mechanism governing the propagation of intense laser pulses in diamond. (interaction of laser radiation with matter. laser plasma)

  16. The Radiation Reaction Effect on Electrons at Super-High Laser Intensities with Application to Ion Acceleration

    SciTech Connect (OSTI)

    Naumova, N. M.; Sokolov, I. V.; Tikhonchuk, V. T.; Schlegel, T.; Nees, J. A.; Yanovsky, V. P.; Labaune, C.; Mourou, G. A.

    2009-07-25

    At super-high laser intensities the radiation back reaction on electrons becomes so significant that its influence on laser-plasma interaction cannot be neglected while simulating these processes with particle-in-cell (PIC) codes. We discuss a way of taking the radiation effect on electrons into account and extracting spatial and frequency distributions of the generated high-frequency radiation. We also examine ponderomotive acceleration of ions in the double layer created by strong laser pulses and we compare an analytical description with PIC simulations as well. We discuss: (1) non-stationary features found in simulations, (2) electron cooling effect due to radiation losses, and (3) the limits of the analytical model.

  17. High-intensity double-pulse X-ray free-electron laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F. J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; et al

    2015-03-06

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitudemore »in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.« less

  18. Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity Laser Pulses

    E-Print Network [OSTI]

    Umstadter, Donald

    Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High%) and a decreased electron-beam divergence angle (by 45%), as compared with single-pulse illumination. Simulations reveal that increased stochastic heating of electrons may have also contributed to the electron-beam

  19. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOE Patents [OSTI]

    Cross, J.B.; Cremers, D.A.

    1986-01-10

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  20. High-resolution electron-ion coincidence spectroscopy of ethanol in intense laser fields

    SciTech Connect (OSTI)

    Hatamoto, T.; Pruemper, G.; Okunishi, M.; Ueda, K.; Mathur, D.

    2007-06-15

    High-resolution electron-ion coincidence spectroscopy is used to (i) map correlations between electrons and ions from atomlike ionization of ethanol by intense 400 and 800 nm light pulses and (ii) disentangle the effects of dissociative multiphoton (MPI) and tunneling (TI) ionization. Electron spectra correlated with C{sup n+} (n=1,2,3) exhibit a continuum structure with a high-energy tail due to inelastic collisions involving rescattered electrons following TI, while those correlated with C{sub 2}H{sub n}O{sup +} have structure characteristic of MPI and above-threshold ionization.

  1. Guiding of Intense Laser Beams in Highly Ionized Plasma Columns Generated by a Fast Capillary Discharge

    E-Print Network [OSTI]

    Rocca, Jorge J.

    potentially result in saturated amplifiers with reduced laser pump energy and increased efficiency [9 to develop discharge-pumped collisional soft x-ray lasers [17­19] and the demonstra- tion of the guiding. The nearly 100 volumetric plasma compression achieved with these fast discharges allows the generation

  2. MeV electrons accelerated backward along laser axis from low energy, high intensity laser-water interactions

    E-Print Network [OSTI]

    Feister, Scott; Morrison, John T; Frische, Kyle D; Orban, Chris; Ngirmang, Gregory; Handler, Abraham; Schillaci, Mark; Chowdhury, Enam A; Freeman, R R; Roquemore, W M

    2015-01-01

    Direct electron spectrum measurements show MeV energy electrons generated backward along the laser axis by a $\\lambda =$ 780 nm, 40 fs, 2.9 mJ short-pulse laser ($1.5 \\cdot 10^{18}$ W/cm$^2$). Electrons pass through a 3 mm hole in the center of the final off-axis paraboloid (OAP) and are characterized by a magnetic spectrometer. The charge collected at the OAP is hundreds of pC per pulse. A mechanism for this super-ponderomotive backward electron acceleration is discussed in the framework of 3D Particle-in-cell simulations.

  3. Relativistic effects in the interaction of high intensity ultra-short laser pulse with collisional underdense plasma

    SciTech Connect (OSTI)

    Abedi, Samira [Physics Department, North Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Dorranian, Davoud [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Abari, Mehdi Etehadi [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Shokri, Babak [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

    2011-09-15

    In this paper, the effect of weakly relativistic ponderomotive force in the interaction of intense laser pulse with nonisothermal, underdense, collisional plasma is studied. Ponderomotive force modifies the electron density and temperature distribution. By considering the weakly relativistic effect and ohmic heating of plasma electrons, the nonlinear dielectric permittivity of plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. It is shown that with considering the ohmic heating of electrons and collisions, the effect of ponderomotive force in weakly relativistic regime leads to steepening the electron density profile and increases the temperature of plasma electrons noticeably. Bunches of electrons in plasma become narrower. By increasing the laser pulse strength, the wavelength of density oscillations decreases. In this regime of laser-plasma interaction, electron temperature increases sharply by increasing the intensity of laser pulse. The amplitude of electric and magnetic fields increases by increasing the laser pulse energy while their wavelength decreases and they lost their sinusoidal form.

  4. Measuring the strong electrostatic and magnetic fields with proton radiography for ultra-high intensity laser channeling on fast ignition

    SciTech Connect (OSTI)

    Uematsu, Y.; Iwawaki, T.; Habara, H., E-mail: habara@eei.eng.osaka-u.ac.jp; Tanaka, K. A. [Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Ivancic, S.; Theobald, W. [Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299 (United States); Lei, A. L. [Shanghai Institute of Laser Plasma, 201800 Shanghai (China)

    2014-11-15

    In order to investigate the intense laser propagation and channel formation in dense plasma, we conducted an experiment with proton deflectometry on the OMEGA EP Laser facility. The proton image was analyzed by tracing the trajectory of mono-energetic protons, which provides understanding the electric and magnetic fields that were generated around the channel. The estimated field strengths (E ? 10{sup 11} V/m and B ? 10{sup 8} G) agree with the predictions from 2D-Particle-in-cell (PIC) simulations, indicating the feasibility of the proton deflectometry technique for over-critical density plasma.

  5. Searching for minicharged particles via birefringence, dichroism and Raman spectroscopy of the vacuum polarized by a high-intensity laser wave

    SciTech Connect (OSTI)

    Villalba-Chįvez, S. Müller, C.

    2013-12-15

    Absorption and dispersion of probe photons in the field of a high-intensity circularly polarized laser wave are investigated. The optical theorem is applied for determining the absorption coefficients in terms of the imaginary part of the vacuum polarization tensor. Compact expressions for the vacuum refraction indices and the photon absorption coefficients are obtained in various asymptotic regimes of interest. The outcomes of this analysis reveal that, far from the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum are small and, in some cases, strongly suppressed. On the contrary, in a vicinity of the region in which the photo-production of a pair occurs, these optical properties are manifest with lasers of moderate intensities. We take advantage of such a property in the search of minicharged particles by considering high-precision polarimetric experiments. In addition, Raman-like electromagnetic waves resulting from the inelastic part of the vacuum polarization tensor are suggested as an alternative form for finding exclusion limits on these hypothetical charge carriers. The envisaged parameters of upcoming high-intensity laser facilities are used for establishing upper bounds on the minicharged particles. -- Highlights: •Via dichroism and birefringence of the vacuum by a strong laser wave, minicharged particles can be probed. •The discovery potential is the highest in a vicinity of the first pair production threshold. •As alternative observable, Raman scattered waves are put forward.

  6. Study of 1–8 keV K-? x-ray emission from high intensity femtosecond laser produced plasma

    SciTech Connect (OSTI)

    Arora, V., E-mail: arora@rrcat.gov.in; Naik, P. A.; Chakera, J. A.; Bagchi, S.; Tayyab, M.; Gupta, P. D. [Laser Plasma Division, Raja Rammana Centre for Advanced Technology, Indore 452 013 (India)] [Laser Plasma Division, Raja Rammana Centre for Advanced Technology, Indore 452 013 (India)

    2014-04-15

    We report an experimental study on the optimization of a laser plasma based x-ray source of ultra-short duration K-? line radiation. The interaction of pulses from a CPA based Ti:sapphire laser (10 TW, 45 fs, 10 Hz) system with magnesium, titanium, iron and copper solid target generates bright 1-8 keV K-? x-ray radiation. The x-ray yield was optimized with the laser pulse duration (at fixed fluence) which is varied in the range of 45 fs to 1.4 ps. It showed a maximum at laser pulse duration of ?740 fs, 420 fs, 350 and 250 fs for Mg (1.3 keV), Ti (4.5 keV), Fe (6.4 keV) and Cu (8.05 keV) respectively. The x-ray yield is observed to be independent of the sign of the chirp. The scaling of the K-? yield (I{sub x} ? I{sub L}{sup ?}) for 45 fs and optimized pulse duration were measured for laser intensities in the region of 3 × 10{sup 14} – 8 × 10{sup 17}. The x-ray yield shows a much faster scaling exponent ? = 1.5, 2.1, 2.4 and 2.6 for Mg, Ti, Fe and Cu respectively at optimized pulse duration compared to scaling exponent of 0.65, 1.3, 1.5, and 1.7 obtained for 45 fs duration laser pulses. The laser to x-ray energy conversion efficiencies obtained for different target materials are ?{sub Mg} = 1.2 × 10{sup ?5}, ?{sub Ti} = 3.1 × 10{sup ?5}, ?{sub Fe} = 2.7 × 10{sup ?5}, ?{sub Cu} = 1.9 × 10{sup ?5}. The results have been explained from the efficient generation of optimal energy hot electrons at longer laser pulse duration. The faster scaling observed at optimal pulse duration indicates that the x-ray source is generated at the target surface and saturation of x-ray emission would appear at larger laser fluence. An example of utilization of the source for measurement of shock-wave profiles in a silicon crystal by time resolved x-ray diffraction is also presented.

  7. Ionization and high-order harmonic generation in aligned benzene by a short intense circularly polarized laser pulse

    E-Print Network [OSTI]

    Moiseyev, Nimrod

    Ionization and high-order harmonic generation in aligned benzene by a short intense circularly and high-order harmonic generation by benzene aligned in the polarization plane of a short circularly pulses 4 . Recently, other types of HHG processes have been dis- covered in molecules. The planar benzene

  8. High Intensity Polarized Electron Gun

    SciTech Connect (OSTI)

    Redwine, Robert P.

    2012-07-31

    The goal of the project was to investigate the possibility of building a very high intensity polarized electron gun for the Electron-Ion Collider. This development is crucial for the eRHIC project. The gun implements a large area cathode, ring-shaped laser beam and active cathode cooling. A polarized electron gun chamber with a large area cathode and active cathode cooling has been built and tested. A preparation chamber for cathode activation has been built and initial tests have been performed. Major parts for a load-lock chamber, where cathodes are loaded into the vacuum system, have been manufactured.

  9. A novel femtosecond-gated, high-resolution, frequency-shifted shearing interferometry technique for probing pre-plasma expansion in ultra-intense laser experiments

    SciTech Connect (OSTI)

    Feister, S. Orban, C.; Nees, J. A.; Morrison, J. T.; Frische, K. D.; Chowdhury, E. A.; Roquemore, W. M.

    2014-11-15

    Ultra-intense laser-matter interaction experiments (>10{sup 18} W/cm{sup 2}) with dense targets are highly sensitive to the effect of laser “noise” (in the form of pre-pulses) preceding the main ultra-intense pulse. These system-dependent pre-pulses in the nanosecond and/or picosecond regimes are often intense enough to modify the target significantly by ionizing and forming a plasma layer in front of the target before the arrival of the main pulse. Time resolved interferometry offers a robust way to characterize the expanding plasma during this period. We have developed a novel pump-probe interferometry system for an ultra-intense laser experiment that uses two short-pulse amplifiers synchronized by one ultra-fast seed oscillator to achieve 40-fs time resolution over hundreds of nanoseconds, using a variable delay line and other techniques. The first of these amplifiers acts as the pump and delivers maximal energy to the interaction region. The second amplifier is frequency shifted and then frequency doubled to generate the femtosecond probe pulse. After passing through the laser-target interaction region, the probe pulse is split and recombined in a laterally sheared Michelson interferometer. Importantly, the frequency shift in the probe allows strong plasma self-emission at the second harmonic of the pump to be filtered out, allowing plasma expansion near the critical surface and elsewhere to be clearly visible in the interferograms. To aid in the reconstruction of phase dependent imagery from fringe shifts, three separate 120° phase-shifted (temporally sheared) interferograms are acquired for each probe delay. Three-phase reconstructions of the electron densities are then inferred by Abel inversion. This interferometric system delivers precise measurements of pre-plasma expansion that can identify the condition of the target at the moment that the ultra-intense pulse arrives. Such measurements are indispensable for correlating laser pre-pulse measurements with instantaneous plasma profiles and for enabling realistic Particle-in-Cell simulations of the ultra-intense laser-matter interaction.

  10. Characterisation of a MeV Bremsstrahlung x-ray source produced from a high intensity laser for high areal density object radiography

    SciTech Connect (OSTI)

    Courtois, C.; Compant La Fontaine, A.; Bazzoli, S.; Bourgade, J. L.; Gazave, J.; Lagrange, J. M.; Landoas, O.; Dain, L. Le; Pichoff, N. [CEA, DAM, DIF, F-91297 Arpajon (France)] [CEA, DAM, DIF, F-91297 Arpajon (France); Edwards, R.; Aedy, C. [AWE Plc., Aldermaston, Reading RG7 4PR (United Kingdom)] [AWE Plc., Aldermaston, Reading RG7 4PR (United Kingdom); Mastrosimone, D.; Pien, G.; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2013-08-15

    Results of an experiment to characterise a MeV Bremsstrahlung x-ray emission created by a short (<10 ps) pulse, high intensity (1.4 × 10{sup 19} W/cm{sup 2}) laser are presented. X-ray emission is characterized using several diagnostics; nuclear activation measurements, a calibrated hard x-ray spectrometer, and dosimeters. Results from the reconstructed x-ray energy spectra are consistent with numerical simulations using the PIC and Monte Carlo codes between 0.3 and 30 MeV. The intense Bremsstrahlung x-ray source is used to radiograph an image quality indicator (IQI) heavily filtered with thick tungsten absorbers. Observations suggest that internal features of the IQI can be resolved up to an external areal density of 85 g/cm{sup 2}. The x-ray source size, inferred by the radiography of a thick resolution grid, is estimated to be approximately 400 ?m (full width half maximum of the x-ray source Point Spread Function)

  11. Fast Ignition relevant study of the flux of high intensity laser generated electrons via a hollow cone into a laser-imploded plasma

    SciTech Connect (OSTI)

    Key, M; Adam, J; Akli, K; Borgheshi, M; Chen, M; Evans, R; Freeman, R; Hatchett, S; Hill, J; Heron, A; King, J; Lancaster, K; Mackinnon, A; Norreys, P; Phillips, T; Romagnani, L; Snavely, R; Stephens, R; Stoeckl, C

    2005-10-11

    An integrated experiment relevant to fast ignition is described. A Cu doped CD spherical shell target is imploded around an inserted hollow Au cone by a six beam 600J, 1ns laser to a peak density of 4gcm{sup -3} and a diameter of 100 {micro}m. A 10 ps, 20TW laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu K{alpha} fluorescence by comparison with a Monte Carlo model and is estimated to carry 15% of the laser energy. Collisional and Ohmic heating are modeled. An electron spectrometer shows significantly greater reduction of the transmitted electron flux than is due to binary collisions and Ohmic potential. Enhanced scattering by instability-induced magnetic fields is suggested.

  12. Fast magnetic field annihilation in the relativistic collisionless regime driven by two ultra-short high-intensity laser pulses

    E-Print Network [OSTI]

    Gu, Y J; Kumar, D; Liu, Y; Singh, S K; Esirkepov, T Zh; Bulanov, S V; Weber, S; Korn, G

    2015-01-01

    The magnetic quadrupole structure formation during the interaction of two ultra-short high power laser pulses with a collisionless plasma is demonstrated with 2.5-dimensional particle-in-cell simulations. The subsequent expansion of the quadrupole is accompanied by magnetic field annihilation in the ultrarelativistic regime, when the magnetic field can not be sustained by the plasma current. This results in a dominant contribution of the displacement current exciting a strong large scale electric?field. This field leads to the conversion of magnetic energy into kinetic energy of accelerated electrons inside the thin current sheet.

  13. High intensity femtosecond enhancement cavities

    E-Print Network [OSTI]

    Abram, Gilberto

    2009-01-01

    To produce extreme ultraviolet radiation via high harmonic generation (HHG) in rare gases, light intensities in excess of 1014 W/cm 2 are required. Usually such high intensity are obtained by parametric amplification of ...

  14. Laser intensity effects in noncommutative QED

    E-Print Network [OSTI]

    Thomas Heinzl; Anton Ilderton; Mattias Marklund

    2010-02-17

    We discuss a two-fold extension of QED assuming the presence of strong external fields provided by an ultra-intense laser and noncommutativity of spacetime. While noncommutative effects leave the electron's intensity induced mass shift unchanged, the photons change significantly in character: they acquire a quasi-momentum that is no longer light-like. We study the consequences of this combined noncommutative strong-field effect for basic lepton-photon interactions.

  15. Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions

    SciTech Connect (OSTI)

    Mori, Warren, B.

    2012-12-01

    We present results from the grant entitled, Ć?Ā?Ć?Ā¢Ć?Ā?Ć?Ā?Ć?Ā?Ć?Ā?Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions.Ć?Ā?Ć?Ā¢Ć?Ā?Ć?Ā?Ć?Ā?Ć?Ā¯ The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

  16. Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile

    SciTech Connect (OSTI)

    Habibi, M.; Ghamari, F.

    2014-05-15

    The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam.

  17. Fast ignition relevant study of the flux of high intensity laser-generated electrons via a hollow cone into a laser-imploded plasma

    SciTech Connect (OSTI)

    Key, M. H.; Chen, M. H.; Hatchett, S. P.; Hill, J. M.; King, J. A.; MacKinnon, A. J.; Patel, P.; Phillips, T.; Snavely, R. A.; Town, R. [University of California, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Adam, J. C.; Heron, A. [Centre de Physique Theorique (UPR14 du CNRS), Ecole Polytechnique, 91128 Palaiseau Cedex (France); Akli, K. U.; Stephens, R. [General Atomics, San Diego, California 92186 (United States); Borghesi, M.; Romagnani, L.; Zepf, M. [Department of Pure and Applied Physics, Queens University of Belfast, Belfast BT7 1NN (United Kingdom); Evans, R. G. [Blackett Laboratory, Imperial College of Science Technology and Medicine, London SW7 2BZ (United Kingdom); Freeman, R. R. [The Ohio State University, Columbus, Ohio 34210 (United States); Habara, H. [Rutherford Appleton Laboratory, Chilton, Oxon, OX11OQX (United Kingdom)] (and others)

    2008-02-15

    An integrated experiment relevant to fast ignition . A Cu-doped deuterated polymer spherical shell target with an inserted hollow Au cone is imploded by a six-beam 900-J, 1-ns laser. A 10-ps, 70-J laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu K{alpha} fluorescence by comparison with a Monte Carlo model. The electrons are estimated to carry about 15% of the laser energy. Collisional and Ohmic heating are modeled, and Ohmic effects are shown to be relatively unimportant. An electron spectrometer shows significantly greater reduction of the transmitted electron flux than is calculated in the model. Enhanced scattering by instability-induced magnetic fields is suggested. An extension of this fluor-based technique to measurement of coupling efficiency to the ignition hot spot in future larger-scale fast ignition experiments is outlined.

  18. Fast ignition relevant study of the flux of high intensity laser-generated electrons via a hollow cone into a laser-imploded plasma

    SciTech Connect (OSTI)

    Key, M

    2007-11-20

    An integrated experiment relevant to fast ignition. A Cu-doped deuterated polymer spherical shell target with an inserted hollow Au cone is imploded by a six-beam 900-J, 1-ns laser. A 10-ps, 70-J laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu K{sub {alpha}} fluorescence by comparison with a Monte Carlo model. The electrons are estimated to carry about 15% of the laser energy. Collisional and Ohmic heating are modeled, and Ohmic effects are shown to be relatively unimportant. An electron spectrometer shows significantly greater reduction of the transmitted electron flux than is calculated in the model. Enhanced scattering by instability-induced magnetic fields is suggested. An extension of this fluor-based technique to measurement of coupling efficiency to the ignition hot spot in future larger-scale fast ignition experiments is outlined.

  19. The interaction of intense subpicosecond laser pulses with underdense plasmas

    SciTech Connect (OSTI)

    Coverdale, C.A.

    1995-05-11

    Laser-plasma interactions have been of interest for many years not only from a basic physics standpoint, but also for their relevance to numerous applications. Advances in laser technology in recent years have resulted in compact laser systems capable of generating (psec), 10{sup 16} W/cm{sup 2} laser pulses. These lasers have provided a new regime in which to study laser-plasma interactions, a regime characterized by L{sub plasma} {ge} 2L{sub Rayleigh} > c{tau}. The goal of this dissertation is to experimentally characterize the interaction of a short pulse, high intensity laser with an underdense plasma (n{sub o} {le} 0.05n{sub cr}). Specifically, the parametric instability known as stimulated Raman scatter (SRS) is investigated to determine its behavior when driven by a short, intense laser pulse. Both the forward Raman scatter instability and backscattered Raman instability are studied. The coupled partial differential equations which describe the growth of SRS are reviewed and solved for typical experimental laser and plasma parameters. This solution shows the growth of the waves (electron plasma and scattered light) generated via stimulated Raman scatter. The dispersion relation is also derived and solved for experimentally accessible parameters. The solution of the dispersion relation is used to predict where (in k-space) and at what frequency (in {omega}-space) the instability will grow. Both the nonrelativistic and relativistic regimes of the instability are considered.

  20. Microengineering laser plasma interactions at relativistic intensities

    E-Print Network [OSTI]

    Jiang, S; Audesirk, H; George, K M; Snyder, J; Krygier, A; Lewis, N S; Schumacher, D W; Pukhov, A; Freeman, R R; Akli, K U

    2015-01-01

    We report on the first successful proof-of-principle experiment to manipulate laser-matter interactions on the microscale using highly ordered Si microwire arrays. The interaction of a high contrast short pulse laser with a flat target via periodic Si microwires yields a substantial enhancement in both total and cut-off energies of the produced electron beam. The self generated electric and magnetic fields behave as an electromagnetic lens that confines and guides electrons between the microwires as they acquire relativistic energies via direct laser acceleration (DLA).

  1. Production of neutrons up to 18 MeV in high-intensity, short-pulse laser matter interactions

    E-Print Network [OSTI]

    . Plasmas 18, 104506 (2011) Charge resolved electrostatic diagnostic of colliding copper laser plasma plumes the 7 Li(d,xn) nuclear reaction (Q ¼ 15 MeV). Radiochromic film and a Thomson parabola ion, such as fusion power plant materials testing,1 contraband detec- tion,2 and fissile material waste disposal,3

  2. Channeling of intense laser beams in underdense plasmas

    SciTech Connect (OSTI)

    Feit, M.D.; Garrison, J.C.; Rubenchik, A.M.

    1997-09-01

    A hydrodynamic simulation is used to show that intense laser pulses propagating in underdense plasmas create stable, long-lived, and completely evacuated channels. At low intensities, I=10{sup 17} W/cm{sup 2}, self focusing seriously distorts the temporal envelope of the pulse, but channeling still occurs. At high intensities, I=10{sup 19} W/cm{sup 2}, channeling can proceed over many diffraction lengths with significant distortion restricted to the leading edge of the pulse. {copyright} {ital 1997} {ital The American Physical Society}

  3. Investigation Of Plasma Produced By High-Energy Low-Intensity Laser Pulses For Implantation Of Ge Ions Into Si And Sio2 Substrates

    SciTech Connect (OSTI)

    Rosinski, M.; Wolowski, J.; Badziak, J.; Parys, P.; Boody, F. P.; Gammino, S.; Krasa, J.; Laska, L.; Pfeifer, M.; Rohlena, K.; Ullschmied, J.; Mezzasalma, A.; Torrisi, L.

    2006-01-15

    The development of implantation techniques requires investigation of laser plasma as a potential source of multiply charged ions. The laser ion source delivers ions with kinetic energy and a charge state dependent on the irradiated target material and the parameters of the laser radiation used. By the focusing the laser beam on the solid target the higher current densities of ions than by using other currently available ion sources can be produced. The crucial issue for efficiency of the ion implantation technology is selection of proper laser beam characteristics. Implantation of different kinds of laser-produced ions into metals and organic materials were performed recently at the PALS Research Center in Prague, in cooperative experiments using 0.4-ns iodine laser pulses having energies up to 750 J at wavelength of 1315 nm or up to 250 J at wavelength of 438 nm. In this contribution we describe the characterization and optimization of laser-produced Ge ion streams as well as analysis of the direct implantation of these ions into Si and SiO2 substrates. The Ge target was irradiated with the use of laser pulses of energy up to 50 J at radiation intensities of {approx}1011 W/cm2 and {approx}2'1013 W/cm2. The implanted samples were placed along the target normal at distances of 17, 31 and 83 cm from the target surface. The ion stream parameters were measured using the time-of-fight method. The depth of ion implantation was determined by the Rutherford backscattering method (RBS). The maximum depth of implantation of Ge ions was {approx}450 nm. These investigations were carried out for optimization of low and medium energy laser-generated Ge ion streams, suitable for specific implantation technique, namely for fabrication of semiconductor nanostructures within the SRAP 'SEMINANO' project.

  4. Multiphoton ionization and high-order harmonic generation of He, Ne, and Ar atoms in intense pulsed laser fields: Self-interaction-free time-dependent density-functional theoretical approach

    E-Print Network [OSTI]

    Chu, Shih-I; Tong, Xiao-Min

    2001-06-12

    We present a detailed study of the multiphoton ionization and high-order harmonic generation (HHG) processes of rare-gas atoms (He, Ne, and Ar) in intense pulsed laser fields by means of a self-interaction-free time-dependent density...

  5. Intense terahertz emission from relativistic circularly polarized laser pulses interaction with overdense plasmas

    SciTech Connect (OSTI)

    Chen, Zi-Yu; Li, Xiao-Ya [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)] [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China); Yu, Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)] [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2013-10-15

    During the interaction of a relativistic circularly polarized laser pulse with an overdense plasma target, the longitudinal motion of bunches of electrons under the action of light pressure and electrostatic restore force can emit intense terahertz (THz) pulses. This mechanism allows high pump laser intensity and large electron number participating in the emission. Two-dimensional particle-in-cell simulations are carried out to investigate the THz emission. The results suggest that such a source can produce remarkably intense THz pulses with energy of several mJ/sr and power of tens of gigawatts, which could find applications in nonlinear studies and relativistic laser-plasma interaction diagnostics.

  6. Nonlinear dynamics of ionization stabilization of atoms in intense laser fields

    E-Print Network [OSTI]

    Michael Norman; C. Chandre; T. Uzer; Peijie Wang

    2014-12-06

    We revisit the stabilization of ionization of atoms subjected to a superintense laser pulse using nonlinear dynamics. We provide an explanation for the lack of complete ionization at high intensity and for the decrease of the ionization probability as intensity is increased. We investigate the role of each part of the laser pulse (ramp-up, plateau, ramp-down) in this process. We emphasize the role of the choice for the ionization criterion, energy versus distance criterion.

  7. Self-interaction-free time-dependent density-functional theory for molecular processes in strong fields:? High-order harmonic generation of H2 in intense laser fields

    E-Print Network [OSTI]

    Chu, Shih-I; Chu, Xi

    2001-01-17

    We present a self-interaction-free time-dependent density-functional theory (TDDFT) for nonperturbative treatment of multiphoton processes of many-electron molecular systems in intense laser fields. The time-dependent ...

  8. Explosive photodissociation of methane induced by ultrafast intense laser

    SciTech Connect (OSTI)

    Kong Fanao; Luo Qi; Xu Huailiang; Sharifi, Mehdi; Song Di; Chin, See Leang

    2006-10-07

    A new type of molecular fragmentation induced by femtosecond intense laser at the intensity of 2x10{sup 14} W/cm{sup 2} is reported. For the parent molecule of methane, ethylene, n-butane, and 1-butene, fluorescence from H (n=3{yields}2), CH (A {sup 2}{delta}, B {sup 2}{sigma}{sup -}, and C {sup 2}{sigma}{sup +}{yields}X {sup 2}{pi}), or C{sub 2} (d {sup 3}{pi}{sub g}{yields}a {sup 3}{pi}{sub u}) is observed in the spectrum. It shows that the fragmentation is a universal property of neutral molecule in the intense laser field. Unlike breaking only one or two chemical bonds in conventional UV photodissociation, the fragmentation caused by the intense laser undergoes vigorous changes, breaking most of the bonds in the molecule, like an explosion. The fragments are neutral species and cannot be produced through Coulomb explosion of multiply charged ion. The laser power dependence of CH (A{yields}X) emission of methane on a log-log scale has a slope of 10{+-}1. The fragmentation is thus explained as multiple channel dissociation of the superexcited state of parent molecule, which is created by multiphoton excitation.

  9. Lateral Electron Transport in High-Intensity Laser-Irradiated Foils Diagnosed by Ion Emission P. McKenna,1,2,* D. C. Carroll,1

    E-Print Network [OSTI]

    Greenaway, Alan

    of the factors influencing the efficiency of longitudinal energy transport in a laser-irradiated target electric-field generation resulting from electron transport. The measurement of large electric fields (0:1 TV=m) millimeters from the laser focus reveals that lateral energy transport continues long after

  10. Emittance of positron beams produced in intense laser plasma interaction

    SciTech Connect (OSTI)

    Chen Hui; Hazi, A.; Link, A.; Anderson, S.; Gronberg, J.; Izumi, N.; Tommasini, R.; Wilks, S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Sheppard, J. C. [SLAC, Standford University, Menlo Park, California 94025 (United States); Meyerhofer, D. D. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Baldis, H. A.; Marley, E.; Park, J.; Williams, G. J. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Fedosejev, R.; Kerr, S. [Department of Applied Science, University of Alberta, Alberta T6G 2R3 (Canada)

    2013-01-15

    The first measurement of the emittance of intense laser-produced positron beams has been made. The emittance values were derived through measurements of positron beam divergence and source size for different peak positron energies under various laser conditions. For one of these laser conditions, we used a one dimensional pepper-pot technique to refine the emittance value. The laser-produced positrons have a geometric emittance between 100 and 500 mm{center_dot}mrad, comparable to the positron sources used at existing accelerators. With 10{sup 10}-10{sup 12} positrons per bunch, this low emittance beam, which is quasi-monoenergetic in the energy range of 5-20 MeV, may be useful as an alternative positron source for future accelerators.

  11. The phase-lock dynamics of the laser wakefield acceleration with an intensity-decaying laser pulse

    SciTech Connect (OSTI)

    Li, Wentao; Liu, Jiansheng Wang, Wentao; Zhang, Zhijun; Chen, Qiang; Tian, Ye; Qi, Rong; Yu, Changhai; Wang, Cheng; Li, Ruxin Xu, Zhizhan; Tajima, T.

    2014-03-03

    An electron beam with the maximum energy extending up to 1.8?GeV, much higher than the dephasing limit, is experimentally obtained in the laser wakefield acceleration with the plasma density of 3.5?×?10{sup 18}?cm{sup ?3}. With particle in cell simulations and theoretical analysis, we find that the laser intensity evolution plays a major role in the enhancement of the electron energy gain. While the bubble length decreases due to the intensity-decay of the laser pulse, the phase of the electron beam in the wakefield can be locked, which contributes to the overcoming of the dephasing. Moreover, the laser intensity evolution is described for the phase-lock acceleration of electrons in the uniform plasma, confirmed with our own simulation. Since the decaying of the intensity is unavoidable in the long distance propagation due to the pump depletion, the energy gain of the high energy laser wakefield accelerator can be greatly enhanced if the current process is exploited.

  12. Response of High-Tc Superconductor Metamaterials to High Intensity...

    Office of Scientific and Technical Information (OSTI)

    Conference: Response of High-Tc Superconductor Metamaterials to High Intensity THz Radiation Citation Details In-Document Search Title: Response of High-Tc Superconductor...

  13. System for obtaining smooth laser beams where intensity variations are reduced by spectral dispersion of the laser light (SSD)

    DOE Patents [OSTI]

    Skupsky, S.; Kessler, T.J.; Short, R.W.; Craxton, S.; Letzring, S.A.; Soures, J.

    1991-09-10

    In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies (''colors'') cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers. 8 figures.

  14. Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile

    SciTech Connect (OSTI)

    Habibi, M.; Ghamari, F.

    2012-10-15

    By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

  15. EFFECTS OF MULTI-ELECTRON CORRELATION ON MULTIPHOTON IONIZATION AND HIGH-ORDER HARMONIC GENERATION OF ATOMIC AND MOLECULAR SYSTEMS IN INTENSE ULTRASHORT LASER FIELDS

    E-Print Network [OSTI]

    Heslar, John

    2009-05-07

    The study of the electron correlation and quantum dynamics of many-electron atoms and molecules in the presence of intense external fields is a subject of much current importance in science and technology. While experimental ...

  16. Device Architecture Simplification of Laser Pattering in High-Volume Crystalline Silicon Solar Cell Fabrication using Intensive Computation for Design and Optimization

    SciTech Connect (OSTI)

    Grupp Mueller, Guenther; Herfurth, Hans; Dunham, Scott; Xu, Baomin

    2013-11-15

    Prices of Si based solar modules have been continuously declining in recent years. Goodrich is pointing out that a significant portion of these cost reductions have come about due to ?economies of scale? benefits, but there is a point of diminishing returns when trying to lower cost by simply expanding production capacity [1]. Developing innovative high volume production technologies resulting in an increase of conversion efficiency without adding significant production cost will be necessary to continue the projected cost reductions. The Foundational Program to Advance Cell Efficiency (F-PACE) is seeking to achieve this by closing the PV efficiency gap between theoretical achievable maximum conversion efficiency - 29% for c-Si - and the current typical production - 18.5% for a typical full area back contact c-Si Solar cell ? while targeting a module cost of $0.50/Watt . The research conducted by SolarWorldUSA and it?s partners within the FPACE framework focused on the development of a Hybrid metal-wrap-through (MWT) and laser-ablated PERC solar cell design employing a extrusion metallization scheme to achieve >20% efficient devices. The project team was able to simulate, develop and demonstrate the technologies necessary to build p-type MWT PERC cells with extruded front contacts. Conversion efficiencies approaching 20% were demonstrated and a path for further efficiency improvements identified. A detailed cost of ownership calculation for such a device was based on a NREL cost model and is predicting a $/Watt cost below 85 cents on a 180 micron substrate. Several completed or planned publications by SolarWorldUSA and our partners are based on the research conducted within this project and are adding to a better understanding of the involved technologies and materials. Several aspects and technologies of the proposed device have been assessed in regards to technical effectiveness and economic feasibility. It has been shown in a pilot demonstration with wafer thicknesses down to 120 micron that further wafer thickness reduction is only economically viable if handling and contact formation limitations are addressed simultaneously. Furthermore the project partners assessed and demonstrated the feasibility of processing wafers with vias connecting front and back sides through a PERC cell process and aligning and connecting those vias with a non-contact metallization. A close cooperation between industry and institutes of higher education in the Pacific Northwest as shown in this project is of direct benefit to the public and is contributing to the education of the next generation of PV engineers and scientist.

  17. Using XFELs for Probing of Complex Interaction Dynamics of Ultra-Intense Lasers with Solid Matter

    E-Print Network [OSTI]

    Kluge, Thomas; Huang, Lingen; Metzkes, Josefine; Schramm, Ulrich; Bussmann, Michael; Cowan, Thomas E

    2013-01-01

    We demonstrate the potential of X-ray free-electron lasers (XFEL) to advancethe understanding of complex plasma dynamics by allowing for the first time nanometer and femtosecond resolution at the same time in plasma diagnostics. Plasma phenomena on such short timescales are of high relevance for many fields of physics, in particular in the ultra-intense ultra-short laser interaction with matter. Highly relevant yet only partially understood phenomena may become directly accessible in experiment. These include relativistic laser absorption at solid targets, creation of energetic electrons and electron transport in warm dense matter, including the seeding and development of surface and beam instabilities, ambipolar expansion, shock formation, and dynamics at the surfaces or at buried layers. We demonstrate the potentials of XFEL plasma probing for high power laser matter interactions using exemplary the small angle X-ray scattering technique, focusing on general considerations for XFEL probing.

  18. High-Intensity Proton Accelerator

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2011-12-27

    Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

  19. High repetition rate fiber lasers

    E-Print Network [OSTI]

    Chen, Jian, Ph. D. Massachusetts Institute of Technology

    2009-01-01

    This thesis reports work in high repetition rate femtosecond fiber lasers. Driven by the applications including optical arbitrary waveform generation, high speed optical sampling, frequency metrology, and timing and frequency ...

  20. Infrared Two-Color Multicycle Laser Field Synthesis for Generating an Intense Attosecond Pulse

    SciTech Connect (OSTI)

    Takahashi, Eiji J.; Lan Pengfei; Nabekawa, Yasuo; Midorikawa, Katsumi [Extreme Photonics Research Group, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Muecke, Oliver D. [Photonics Institute, Vienna University of Technology, Gusshausstrasse 27-387, A-1040 Vienna (Austria)

    2010-06-11

    We propose and demonstrate the generation of a continuum high-order harmonic spectrum by mixing multicycle two-color (TC) laser fields with the aim of obtaining an intense isolated attosecond pulse. By optimizing the wavelength of a supplementary infrared pulse in a TC field, a continuum harmonic spectrum was created around the cutoff region without carrier-envelope phase stabilization. The obtained harmonic spectra clearly show the possibility of generating isolated attosecond pulses from a multicycle TC laser field, which is generated by an 800 nm, 30 fs pulse mixed with a 1300 nm, 40 fs pulse. Our proposed method enables us not only to relax the requirements for the pump pulse duration but also to reduce ionization of the harmonic medium. This concept opens the door to create an intense isolated attosecond pulse using a conventional femtosecond laser system.

  1. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    SciTech Connect (OSTI)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi; Bakule, Pavel; Yokoyama, Koji; Ishida, Katsuhiko; Iwasaki, Masahiko

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  2. Electrons trajectories around a bubble regime in intense laser plasma interaction

    SciTech Connect (OSTI)

    Lu, Ding; Xie, Bai-Song; Ali Bake, Muhammad; Sang, Hai-Bo; Zhao, Xue-Yan; Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 ; Wu, Hai-Cheng

    2013-06-15

    Some typical electrons trajectories around a bubble regime in intense laser plasma interaction are investigated theoretically. By considering a modification of the fields and ellipsoid bubble shape due to the presence of residual electrons in the bubble regime, we study in detail the electrons nonlinear dynamics with or without laser pulse. To examine the electron dynamical behaviors, a set of typical electrons, which locate initially at the front of the bubble, on the transverse edge and at the bottom of the bubble respectively, are chosen for study. It is found that the range of trapped electrons in the case with laser pulse is a little narrower than that without laser pulse. The partial phase portraits for electrons around the bubble are presented numerically and their characteristic behaviors are discussed theoretically. Implication of our results on the high quality electron beam generation is also discussed briefly.

  3. Plasma discreteness eects in the presence of an intense, ultrashort laser pulse

    E-Print Network [OSTI]

    Plasma discreteness eects in the presence of an intense, ultrashort laser pulse V.I. Savchenko, intense laser pulse are investigated. Although, for most plasmas of interest, the damping of the laser pulse is due to collective plasma eects, in certain regimes the energy absorbed in the plasma micro#12

  4. Plasma discreteness effects in the presence of an intense, ultrashort laser pulse

    E-Print Network [OSTI]

    Plasma discreteness effects in the presence of an intense, ultrashort laser pulse V. I. Savchenko irradiated by an ultrashort, intense laser pulse are investigated. Although, for most plasmas of interest, the damping of the laser pulse is due to collective plasma effects, in certain regimes the energy absorbed

  5. Plasma discreteness effects in the presence of an intense, ultrashort laser pulse

    E-Print Network [OSTI]

    Plasma discreteness effects in the presence of an intense, ultrashort laser pulse V.I. Savchenko, intense laser pulse are investigated. Although, for most plasmas of interest, the damping of the laser pulse is due to collective plasma effects, in certain regimes the energy absorbed in the plasma

  6. Molecular Dynamics of Methylamine, Methanol, and Methyl Fluoride Cations in Intense 7 Micron Laser Fields

    E-Print Network [OSTI]

    Schlegel, H. Bernhard

    Molecular Dynamics of Methylamine, Methanol, and Methyl Fluoride Cations in Intense 7 Micron Laser of methylamine (CH3NH2 + ), methanol (CH3OH+ ), and methyl fluoride (CH3F+ ) cations by short, intense laser 7 m laser pulses. This work is motivated by recent studies of methanol cations by Yamanouchi and co

  7. Delivering High IntensityDelivering High Intensity Proton Beam:Proton Beam

    E-Print Network [OSTI]

    McDonald, Kirk

    11 Delivering High IntensityDelivering High Intensity Proton Beam:Proton Beam: Lessons for the NextFACT08NuFACT08 Ā­Ā­ 4 July4 July S. ChildressS. Childress Ā­Ā­ Proton BeamsProton Beams 22 Presentation OutlinePresentation Outline Key Proton Beam ConsiderationsKey Proton Beam Considerations The First

  8. 2d-PIC simulation of atomic clusters in intense laser fields F. Greschik and H.-J. Kull,

    E-Print Network [OSTI]

    Kull, Hans-Jörg

    Title page Full title 2d-PIC simulation of atomic clusters in intense laser fields Authors F of atomic clusters in intense laser fields Abstract Collective absorption of intense laser pulses by atomic by electron emission increases as a power law with the laser intensity. The absorbed energy per electron

  9. Hole boring in a DT pellet and fast ion ignition with ultra-intense laser pulses

    E-Print Network [OSTI]

    Naumova, N; Tikhonchuk, V T; Labaune, C; Sokolov, I V; Mourou, G; 10.1103/PhysRevLett.102.025002

    2009-01-01

    Recently achieved high intensities of short laser pulses open new prospects in their application to hole boring in inhomogeneous overdense plasmas and for ignition in precompressed DT fusion targets. A simple analytical model and numerical simulations demonstrate that pulses with intensities exceeding 1022 W/cm2 may penetrate deeply into the plasma as a result of efficient ponderomotive acceleration of ions in the forward direction. The penetration depth as big as hundreds of microns depends on the laser fluence, which has to exceed a few tens of GJ/cm2. The fast ions, accelerated at the bottom of the channel with an efficiency of more than 20%, show a high directionality and may heat the precompressed target core to fusion conditions.

  10. Intensity-resolved Above Threshold Ionization Yields of Atoms with Ultrashort Laser Pulses 

    E-Print Network [OSTI]

    Hart, Nathan Andrew

    2012-10-19

    The above threshold ionization (ATI) spectra provide a diversity of information about a laser-atom ionization process such as laser intensity, pulse duration, carrier envelope phase, and atomic energy level spacing. However, the spatial distribution...

  11. High power gas laser amplifier

    DOE Patents [OSTI]

    Leland, Wallace T. (Los Alamos, NM); Stratton, Thomas F. (Los Alamos, NM)

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  12. Caustic structures in the spectrum of x-ray Compton scattering off electrons driven by a short intense laser pulse

    E-Print Network [OSTI]

    Seipt, D; Fritzsche, S; Kampfer, B

    2015-01-01

    We study the Compton scattering of x-rays off electrons that are driven by a relativistically intense short optical laser pulse. The frequency spectrum of the laser-assisted Compton radiation shows a broad plateau in the vicinity of the laser-free Compton line due to a nonlinear mixing between x-ray and laser photons. Special emphasis is placed on how the shape of the short assisting laser pulse affects the spectrum of the scattered x-rays. In particular, we observe sharp peak structures in the plateau region, whose number and locations are highly sensitive to the laser pulse shape. These structures are interpreted as spectral caustics by using a semiclassical analysis of the laser-assisted QED matrix element.

  13. Laser Fusion Energy The High Average Power

    E-Print Network [OSTI]

    Laser Fusion Energy and The High Average Power Program John Sethian Naval Research Laboratory Dec for Inertial Fusion Energy with lasers, direct drive targets and solid wall chambers Lasers DPPSL (LLNL) Kr posters Snead Payne #12;Laser(s) Goals 1. Develop technologies that can meet the fusion energy

  14. Correlated-intensity velocimeter for arbitrary reflector for laser-produced plasma experiments

    SciTech Connect (OSTI)

    Wang Zhehui; Luo Shengnian; Barnes, Cris W.; Briggs, Matthew E.; Paisley, Dennis L.; Paul, Stephen F.

    2006-10-15

    A laser-based technique, called correlated-intensity velocimeter for arbitrary reflector (CIVAR), is described for velocity measurement of reflecting surfaces in real time. Velocity versus time is an important measurement in laser-produced high-energy density plasma experiments because the motion of the surface depends on both the equation of the state of the surface material and laser-produced plasma. The physics and working principle of CIVAR are the same as those of a previous concept that resolves Doppler shift of plasma light emission using a pair of narrow passband interference filters. One unique feature of CIVAR is that a reflected laser beam is used instead of plasma emission. Therefore, CIVAR is applicable to both emitting and nonemitting reflecting surfaces. Other advantages of CIVAR include its simplicity, lower cost, and unambiguous data analysis that can be fully automated. The design of a single-point CIVAR is described in detail with emphasis on laser wavelength selection and signal-to-noise ratio. The single-point CIVAR system can be expanded into a multiple-point system straightforwardly. It is possible to use CIVAR concept to construct a two-dimensional imaging system for a nonuniform velocity field of a large reflecting surface; such a velocity imaging system may have applications beyond laser-produced plasma experiments, for example, in shock compression of condensed matter.

  15. High energy photon production in strong colliding laser beams

    E-Print Network [OSTI]

    Michael Kuchiev; Julian Ingham

    2015-07-21

    The collision of two intense, low-frequency laser beams is considered. The $e^-e^+$ pairs created in this field are shown to exhibit recollisions, which take place at high energy accumulated due to the wiggling of fermions. The resulting $e^-e^+$ annihilation produces high energy photons, or heavy particles. The coherent nature of the laser field provides strong enhancement of the probability of these events. Analytical and numerical results are outlined.

  16. Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse

    E-Print Network [OSTI]

    Umstadter, Donald

    Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse Xiaofang Wang filamentation and beam breakup. These results suggest an approach for generating a beam of femtosecond, Me-intensity lasers has made it pos- sible to study extreme physics on a tabletop. Among the studies, the generation

  17. COLLIMATION OPTIMIZATION IN HIGH INTENSITY RINGS.

    SciTech Connect (OSTI)

    CATALAN-LASHERAS,N.

    2001-06-18

    In high intensity proton rings, collimation is needed in order to maintain reasonable levels of residual activation and allow hands-on maintenance. Small acceptance to emittance ratio and restrained longitudinal space become important restrictions when dealing with low energy rings. The constraints and specifications when designing a collimation system for this type of machine will be reviewed. The SNS accumulator ring will serve as an examples long which we will illustrate the optimization path. Experimental studies of collimation with 1.3 GeV proton beams are currently under way in the U-70 machine in Protvino. The first results will be presented.

  18. Generation of Stable (3+1)-dimensional High-intensity Ultrashort Light Pulses

    SciTech Connect (OSTI)

    Todorov, T. P.; Koprinkov, I. G. [Department of Applied Physics, Technical University of Sofia, 1000 Sofia (Bulgaria); Todorova, M. E. [College of Energetics and Electronics, Technical University of Sofia, 1000 Sofia (Bulgaria); Todorov, M. D. [Faculty of Appl. Math. and Informatics, Technical University of Sofia, 1000 Sofia (Bulgaria)

    2010-11-25

    The spatiotemporal dynamics of high-intensity femtosecond laser pulses is studied within a rigorous physical model. The pulse propagation is described by the nonlinear envelope equation. The propagation and the material equations are solved self-consistently at realistic physical conditions. Self-compression of the pulse around single-cycle regime and dramatic increase of the pulse intensity is found. At certain conditions, the peak intensity, transversal width, time duration, and the spatiotemporal pulse shape remain stable with the propagation of the pulse, resembling a soliton formation process. This, to our knowledge, is the first simulation of high-intensity ultrashort soliton formation dynamics in the (3+1)-dimensional case.

  19. High intensity discharge device containing oxytrihalides

    DOE Patents [OSTI]

    Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

    1987-06-09

    A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

  20. High precision, rapid laser hole drilling

    DOE Patents [OSTI]

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2013-04-02

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  1. High precision, rapid laser hole drilling

    DOE Patents [OSTI]

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2005-03-08

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  2. High precision, rapid laser hole drilling

    DOE Patents [OSTI]

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2007-03-20

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  3. High Power Lasers... Another approach to

    E-Print Network [OSTI]

    1 High Power Lasers... Another approach to Fusion Energy John Sethian Plasma Physics Division Naval drive targets Can lead to an attractive electricity generating power plant Developing Laser Fusion Average Power Laser (HAPL) Program #12;4 Electricity Generator Reaction chamber The laser fusion energy

  4. A search for the sulphur hexafluoride cation with intense, few cycle laser pulses

    SciTech Connect (OSTI)

    Dota, Krithika; Mathur, Deepak; Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 ; Dharmadhikari, Aditya K.; Dharmadhikari, Jayashree A.; Patra, Kaustuv; Tiwari, Ashwani K.

    2013-11-21

    It is well established that upon ionization of sulphur hexafluoride, the SF{sub 6}{sup +} ion is never observed in mass spectra. Recent work with ultrashort intense laser pulses has offered indications that when strong optical field are used, the resulting “bond hardening” can induce changes in the potential energy surfaces of molecular cations such that molecular ions that are normally unstable may, indeed, become metastable enough to enable their detection by mass spectrometry. Do intense, ultrashort laser pulses permit formation of SF{sub 6}{sup +}? We have utilized intense pulses of 5 fs, 11 fs, and 22 fs to explore this possibility. Our results are negative: no evidence is discovered for SF{sub 6}{sup +}. However, multiply charged sulphur and fluorine ions from highly charged SF{sub 6}{sup q+} ions are observed that enable us to resolve the controversy regarding the kinetic energy release accompanying formation of F{sup +} fragment ions. Quantum chemical computations of field-distorted potential energy curves of SF{sub 6} and its molecular ion enable us to rationalize our non-observation of SF{sub 6}{sup +}. Our findings have implications for high harmonic generation from SF{sub 6} in the few-cycle regime.

  5. Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries

    SciTech Connect (OSTI)

    Cooper, Kristie L.; Wang, Anbo; Pickrell, Gary R.

    2006-11-14

    This report summarizes technical progress during the program “Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries”, performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The objective of this program was to use technology recently invented at Virginia Tech to develop and demonstrate the application of self-calibrating optical fiber temperature and pressure sensors to several key energy-intensive industries where conventional, commercially available sensors exhibit greatly abbreviated lifetimes due primarily to environmental degradation. A number of significant technologies were developed under this program, including • a laser bonded silica high temperature fiber sensor with a high temperature capability up to 700°C and a frequency response up to 150 kHz, • the world’s smallest fiber Fabry-Perot high temperature pressure sensor (125 x 20 ?m) with 700°C capability, • UV-induced intrinsic Fabry-Perot interferometric sensors for distributed measurement, • a single crystal sapphire fiber-based sensor with a temperature capability up to 1600°C. These technologies have been well demonstrated and laboratory tested. Our work plan included conducting major field tests of these technologies at EPRI, Corning, Pratt & Whitney, and Global Energy; field validation of the technology is critical to ensuring its usefulness to U.S. industries. Unfortunately, due to budget cuts, DOE was unable to follow through with its funding commitment to support Energy Efficiency Science Initiative projects and this final phase was eliminated.

  6. Apparatus and process for active pulse intensity control of laser beam

    DOE Patents [OSTI]

    Wilcox, Russell B. (Oakland, CA)

    1992-01-01

    An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

  7. Dynamics of an electron in a relativistically intense laser field including radiaion reaction

    SciTech Connect (OSTI)

    Galkin, A. L., E-mail: galkin@kapella.gpi.ru [Prokhorov General Physics Institute of the Russian Academy of Science (Russian Federation)

    2012-08-15

    The dynamics of an electron in a relativistically intense laser pulse field is described with the radiation reaction being taken into account. The study is based on solving the Newton equation with the Lorentz and the radiation reaction forces. Validation is provided for an iteration technique which makes it possible to remove the discrepancies found in the theoretical models of radiation reaction. It is demonstrated that an electron having a high initial velocity and colliding head-on with a laser pulse sheds a considerable part of its kinetic energy due to the radiation reaction. A broadening of the electromagnetic pulse emitted by the electron occurs as a result of the same effect. The findings obtained can be used to experimentally verify the effect of radiation reaction.

  8. High power laser perforating tools and systems

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-04-22

    ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

  9. Collapse and revival of electromagnetic cascades in focused intense laser pulses

    E-Print Network [OSTI]

    A. A. Mironov; N. B. Narozhny; A. M. Fedotov

    2014-07-24

    We consider interaction of a high-energy electron beam with two counterpropagating femtosecond laser pulses. Nonlinear Compton scattering and electron-positron pair production by the emitted photons result in development of an electromagnetic "shower-type" cascade, which however collapses rather quickly due to energy losses by secondary particles. Nevertheless, the laser field accelerates the low-energy electrons and positrons trapped in the focal region, thus giving rise to development of electromagnetic cascade of another type ("avalanche-type"). This effect of cascade collapse and revival can be observed at the electron beam energy of the order of several GeV and intensity of the colliding laser pulses of the level of $10^{24}$W/cm$^2$. This means that it can be readily observed at the novel laser facilities which are either planned for the nearest future, or are already under construction. The proposed experimental setup provides the most realistic and promissory way to observe the "avalanche-type" cascades.

  10. Collapse and revival of electromagnetic cascades in focused intense laser pulses

    E-Print Network [OSTI]

    Mironov, A A; Fedotov, A M

    2014-01-01

    We consider interaction of a high-energy electron beam with two counterpropagating femtosecond laser pulses. Nonlinear Compton scattering and electron-positron pair production by the emitted photons result in development of an electromagnetic "shower-type" cascade, which however collapses rather quickly due to energy losses by secondary particles. Nevertheless, the laser field accelerates the low-energy electrons and positrons trapped in the focal region, thus giving rise to development of electromagnetic cascade of another type ("avalanche-type"). This effect of cascade collapse and revival can be observed at the electron beam energy of the order of several GeV and intensity of the colliding laser pulses of the level of $10^{24}$W/cm$^2$. This means that it can be readily observed at the novel laser facilities which are either planned for the nearest future, or are already under construction. The proposed experimental setup provides the most realistic and promissory way to observe the "avalanche-type" cascad...

  11. Photoionization dynamics and angular squeezing phenomenon in intense long-wavelength laser fields

    E-Print Network [OSTI]

    Chu, Shih-I; Zhou, Zhongyuan

    2011-03-11

    We develop a coherent-state Ehrenfest trajectory (CSET) approach for the nonperturbative study of full electronic and nuclear dynamics of molecules interacting with intense laser fields. In this approach, electrons and ...

  12. Stretchers and compressors for ultra-high power laser systems

    SciTech Connect (OSTI)

    Yakovlev, I V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2014-05-30

    This review is concerned with pulse stretchers and compressors as key components of ultra-high power laser facilities that take advantage of chirped-pulse amplification. The potentialities, characteristics, configurations and methods for the matching and alignment of these devices are examined, with particular attention to the history of the optics of ultra-short, ultra-intense pulses before and after 1985, when the chirped-pulse amplification method was proposed, which drastically changed the view of the feasibility of creating ultra-high power laser sources. The review is intended primarily for young scientists and experts who begin to address the amplification and compression of chirped pulses, experts in laser optics and all who are interested in scientific achievements in the field of ultra-high power laser systems. (review)

  13. Ion Acceleration from the Interaction of Ultra-Intense Lasers with Solid Foils

    SciTech Connect (OSTI)

    Allen, M

    2004-11-24

    The discovery that ultra-intense laser pulses (I > 10{sup 18} W/cm{sup 2}) can produce short pulse, high energy proton beams has renewed interest in the fundamental mechanisms that govern particle acceleration from laser-solid interactions. Experiments have shown that protons present as hydrocarbon contaminants on laser targets can be accelerated up to energies > 50 MeV. Different theoretical models that explain the observed results have been proposed. One model describes a front-surface acceleration mechanism based on the ponderomotive potential of the laser pulse. At high intensities (I > 10{sup 18} W/cm{sup 2}), the quiver energy of an electron oscillating in the electric field of the laser pulse exceeds the electron rest mass, requiring the consideration of relativistic effects. The relativistically correct ponderomotive potential is given by U{sub p} = ([1 + I{lambda}{sup 2}/1.3 x 10{sup 18}]{sup 1/2} - 1) m{sub o}c{sup 2}, where I{lambda}{sup 2} is the irradiance in W {micro}m{sup 2}/cm{sup 2} and m{sub o}c{sup 2} is the electron rest mass. At laser irradiance of I{lambda}{sup 2} {approx} 10{sup 20} W {micro}m{sup 2}/cm{sup 2}, the ponderomotive potential can be of order several MeV. A few recent experiments--discussed in Chapter 3 of this thesis--consider this ponderomotive potential sufficiently strong to accelerate protons from the front surface of the target to energies up to tens of MeV. Another model, known as Target Normal Sheath Acceleration (TNSA), describes the mechanism as an electrostatic sheath on the back surface of the laser target. According to the TNSA model, relativistic hot electrons created at the laser-solid interaction penetrate the foil where a few escape to infinity. The remaining hot electrons are retained by the target potential and establish an electrostatic sheath on the back surface of the target. In this thesis we present several experiments that study the accelerated ions by affecting the contamination layer from which they originate. Radiative heating was employed as a method of removing contamination from palladium targets doped with deuterium. We present evidence that ions heavier than protons can be accelerated if hydrogenous contaminants that cover the laser target can be removed. We show that deuterons can be accelerated from the deuterated-palladium target, which has been radiatively heated to remove contaminants. Impinging a deuteron beam onto a tritiated-titanium catcher could lead to the development of a table-top source of short-pulse, 14-MeV fusion neutrons. We also show that by using an argon-ion sputter gun, contaminants from one side of the laser target can be selectively removed without affecting the other side. We show that irradiating a thin metallic foil with an ultra-intense laser pulse produces a proton beam with a yield of 1.5-2.5 10{sup 11} and temperature, kT = 1.5 MeV with a maximum proton energy > 9 MeV. Removing contaminants from the front surface of the laser target with an argon-ion sputter gun, had no observable effect on the proton beam. However, removing contaminants from the back surface of the laser target reduced the proton beam by two orders of magnitude to, at most, a yield of {approx} 10{sup 9} and a maximum proton energy < 4 MeV. Based on these observations, we conclude that the majority (> 99%) of high energy protons (E > 5 MeV) from the interaction of an ultra-intense laser pulse with a thin foil originate on the back surface of the foil--as predicted by the TNSA model. Our experimental results are in agreement with PIC simulations showing back surface protons reach energies up to 13 MeV, while front surface protons reach a maximum energy of 4 MeV. Well diagnosed and controllable proton beams will have many applications: neutron radiography, material damage studies, production of medical isotopes, and as a high-resolution radiography tool for diagnosing opaque materials and plasmas. Well collimated and focusable ion beams may also prove beneficial for alternative inertial-fusion concepts such as proton fast ignition, a pote

  14. On the control of filamentation of intense laser beams propagating in underdense plasma

    SciTech Connect (OSTI)

    Williams, E.A. [Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States)

    2006-05-15

    In indirect drive inertial confinement fusion ignition designs, the laser energy is delivered into the hohlraum through the laser entrance holes (LEHs), which are sized as small as practicable to minimize x-ray radiation losses. On the other hand, deleterious laser plasma processes, such as filamentation and stimulated backscatter, typically increase with laser intensity. Ideally, therefore, the laser spot shape should be a close fit to the LEH, with uniform (envelope) intensity in the spot and minimal energy at larger radii spilling onto the LEH material. This keeps the laser intensity as low as possible, consistent with the area of the LEH aperture and the power requirements of the design. This can be achieved (at least for apertures significantly larger than the laser's aberrated focal spot) by the use of custom-designed phase plates. However, outfitting the 192-beam National Ignition Facility [J. A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Tech. 26, 755 1994)] laser with multiple sets of phase plates optimized for a variety of different LEH aperture sizes is an expensive proposition. It is thus important to assess the impact on laser-plasma interaction processes of using phase plates with a smaller than optimum focal spot (or even no phase plates at all{exclamation_point}) and then defocusing the beam to expand it to fill the LEH and lower its intensity. Significant effects are found from changes in the characteristic sizes of the laser speckle, from the lack of uniformity of the laser envelope out of the focal plane and on the efficacy of additional polarization smoothing and/or smoothing by spectral dispersion (SSD). These effects are quantified with analytic estimates and simulations using PF3D, our laser-plasma interaction code.

  15. Unveiling temporal correlations characteristic to phase transition in the intensity of a fibre laser radiation

    E-Print Network [OSTI]

    Andres Aragoneses; Laura Carpi; Nikita Tarasov; Dmitry V. Churkin; M. C. Torrent; Cristina Masoller; Sergei K. Turitsyn

    2015-06-09

    We use advanced statistical tools of time-series analysis to characterize the dynamical complexity of the transition to optical wave turbulence in a fibre laser. Ordinal analysis and the horizontal visibility graph applied to the experimentally measured laser output intensity reveal the presence of temporal correlations during the transition from the laminar to the turbulent lasing regimes. Both methods unveil coherent structures with well defined time-scales and strong correlations both, in the timing of the laser pulses and in their peak intensities. Our approach is generic and may be used in other complex systems that undergo similar transitions involving the generation of extreme fluctuations.

  16. Compact and highly efficient laser pump cavity

    DOE Patents [OSTI]

    Chang, Jim J. (Dublin, CA); Bass, Isaac L. (Castro Valley, CA); Zapata, Luis E. (Livermore, CA)

    1999-01-01

    A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

  17. The Fermilab Main Injector: high intensity operation and beam...

    Office of Scientific and Technical Information (OSTI)

    The Fermilab Main Injector: high intensity operation and beam loss control Authors: Brown, Bruce C. ; Adamson, Philip ; Capista, David ; Chou, Weiren ; Kourbanis, Ioanis ;...

  18. High harmonic generation spectra of aligned benzene in circular polarized laser field

    E-Print Network [OSTI]

    Moiseyev, Nimrod

    High harmonic generation spectra of aligned benzene in circular polarized laser field Petra Zda-order harmonic generation in benzene, aligned in the polarization plane of circular polarized laser field-lived resonance state up to the intensity of about 90 TW cm 2 . The high-order harmonics emitted by the system

  19. LIQUID METAL JET TARGETS FOR INTENSE HIGH ENERGY BEAMS

    E-Print Network [OSTI]

    McDonald, Kirk

    LIQUID METAL JET TARGETS FOR INTENSE HIGH ENERGY BEAMS G. I. Silvestrov, Budker Institute for Nuclear Physics Novosibirsk, August 1998. #12;1 LIQUID METAL JET TARGETS FOR INTENSE HIGH ENERGY BEAMS target of liquid metal. The technical solution is producing the target in the form of flat jet flowing

  20. Generation of short gamma-ray pulses on electron bunches formed in intense interfering laser beams with tilted fronts

    SciTech Connect (OSTI)

    Korobkin, V V; Romanovskiy, M Yu; Trofimov, V A; Shiryaev, O B

    2014-05-30

    It is shown that in the interference of multiple laser pulses with a relativistic intensity, phase and amplitude fronts of which are tilted at an angle with respect to their wave vector, effective traps of charged particles, which are moving at the velocity of light, are formed. Such traps are capable of capturing and accelerating the electrons produced in the ionisation of low-density gas by means of laser radiation. The accelerated electrons in the traps form a bunch, whose dimensions in all directions are much smaller than the laser radiation wavelength. Calculations show that the energy of accelerated electrons may amount to several hundred GeV at experimentally accessible relativistic laser intensities. As a result of the inverse Compton scattering, gamma-quanta with a high energy and narrow radiation pattern are emitted when these electrons interact with a laser pulse propagating from the opposite direction. The duration of emitted gamma-ray pulses constitutes a few attoseconds. The simulation is performed by solving the relativistic equation of motion for an electron with a relevant Lorentz force. (interaction of radiation with matter)

  1. HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS

    SciTech Connect (OSTI)

    Chen, H; Wilks, S C; Kruer, W; Patel, P; Shepherd, R

    2008-10-08

    Measurements of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using an electron spectrometer are presented. These measurements were performed on the Vulcan petawatt laser at Rutherford Appleton Laboratory and the Callisto laser at Lawrence Livermore National Laboratory. The effective hot electron temperatures (T{sub hot}) have been measured for laser intensities (I{lambda}{sup 2}) from 10{sup 18} W/cm{sup 2} {micro}m{sup 2} to 10{sup 21} W/cm{sup 2} {micro}m{sup 2} for the first time, and T{sub hot} is found to increase as (I{lambda}{sup 2}){sup 0.34} {+-} 0.4. This scaling agrees well with the empirical scaling published by Beg et al. (1997), and is explained by a simple physical model that gives good agreement with experimental results and particle-in-cell simulations.

  2. Axial magnetic field generation by intense circularly polarized laser pulses in underdense plasmas

    SciTech Connect (OSTI)

    Naseri, N.; Rozmus, W. [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); Bychenkov, V. Yu. [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); P. N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation)

    2010-08-15

    Axial magnetic field generation by intense circularly polarized laser beams in underdense plasmas has been studied with three-dimensional particle-in-cell simulations and by means of theoretical analysis. Comparisons between analytical models and simulation results have identified an inverse Faraday effect as the main mechanism of the magnetic field generation in inhomogeneous plasmas. The source of azimuthal nonlinear currents and of the axial magnetic field depends on the transverse inhomogeneities of the electron density and laser intensity. The fields reach a maximum strength of several tens of megagauss for laser pulses undergoing relativistic self-focusing and channeling in moderately relativistic regime. Ultrarelativistic laser conditions inhibit magnetic field generation by directly reducing a source term and by generating fully evacuated plasma channels.

  3. Apparatus for advancing a wellbore using high power laser energy

    DOE Patents [OSTI]

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  4. High power regenerative laser amplifier

    DOE Patents [OSTI]

    Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.

    1994-02-08

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

  5. Scientific applications for high-energy lasers

    SciTech Connect (OSTI)

    Lee, R.W. [comp.

    1994-03-01

    The convergence of numerous factors makes the time ripe for the development of a community of researchers to use the high-energy laser for scientific investigations. This document attempts to outline the steps necessary to access high-energy laser systems and create a realistic plan to implement usage. Since an academic/scientific user community does not exist in the USA to any viable extent, we include information on present capabilities at the Nova laser. This will briefly cover laser performance and diagnostics and a sampling of some current experimental projects. Further, to make the future possibilities clearer, we will describe the proposed next- generation high-energy laser, named for its inertial fusion confinement (ICF) goal, the multi-megaJoule, 500-teraWatt National Facility, or NIF.

  6. High-intensity beam collimation and targetry

    SciTech Connect (OSTI)

    Mokhov, N.V.; /Fermilab

    2006-11-01

    Principles, design criteria and realization of reliable collimation systems for the high-power accelerators and hadron colliders are described. Functionality of collimators as the key elements of the machine protection system are discussed along with the substantial progress on the crystal collimation front. The key issues are considered in design of high-power target systems and achieving their best performance. Simulation code requirements are presented.

  7. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Seeding Yields High-Power Coherent Terahertz Radiation Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Wednesday, 25 April 2007 00:00 Researchers at...

  8. High-Performance OPCPA Laser System

    SciTech Connect (OSTI)

    Zuegel, J.D.; Bagnoud, V.; Bromage, J.; Begishev, I.A.; Puth, J.

    2006-07-13

    A high-performance optical parametric chirped-pulse amplifier (OPCPA) system has been demonstrated as a prototype for the front end of the OMEGA Extended Performance (EP) Laser System.

  9. Systems for controlling the intensity variations in a laser beam and for frequency conversion thereof

    DOE Patents [OSTI]

    Skupsky, S.; Craxton, R.S.; Soures, J.

    1990-10-02

    In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temporal oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation. 16 figs.

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

    SciTech Connect (OSTI)

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

    2011-08-31

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

  11. A proposal for testing subcritical vacuum pair production with high power lasers

    E-Print Network [OSTI]

    Gregori, G; Rajeev, P P; Chen, H; Clarke, R J; Huffman, T; Murphy, C D; Prozorkevich, A V; Roberts, C D; Röpke, G; Schmidt, S M; Smolyansky, S A; Wilks, S; Bingham, R; 10.1016/j.hedp.2009.11.001

    2010-01-01

    We present a proposal for testing the prediction of non-equilibrium quantum field theory below the Schwinger limit. The proposed experiments should be able to detect a measurable number of gamma rays resulting from the annihilation of pairs in the focal spot of two opposing high intensity laser beams. We discuss the dependence of the expected number of gamma rays with the laser parameters and compare with the estimated background level of gamma hits for realistic laser conditions.

  12. A proposal for testing subcritical vacuum pair production with high power lasers

    E-Print Network [OSTI]

    G. Gregori; D. B. Blaschke; P. P. Rajeev; H. Chen; R. J. Clarke; T. Huffman; C. D. Murphy; A. V. Prozorkevich; C. D. Roberts; G. Röpke; S. M. Schmidt; S. A. Smolyansky; S. Wilks; R. Bingham

    2010-05-18

    We present a proposal for testing the prediction of non-equilibrium quantum field theory below the Schwinger limit. The proposed experiments should be able to detect a measurable number of gamma rays resulting from the annihilation of pairs in the focal spot of two opposing high intensity laser beams. We discuss the dependence of the expected number of gamma rays with the laser parameters and compare with the estimated background level of gamma hits for realistic laser conditions.

  13. High energy laser beam dump

    DOE Patents [OSTI]

    Halpin, John (Tracy, CA)

    2004-09-14

    The laser beam dump is positioned in a housing. An absorbing glass plate means is operatively connected to the housing. A heat sync means for extracting heat from the absorbing glass plate means is operatively connected to the housing and operatively connected to the absorbing glass plate means.

  14. Using X-ray free-electron lasers for probing of complex interaction dynamics of ultra-intense lasers with solid matter

    SciTech Connect (OSTI)

    Kluge, T., E-mail: t.kluge@hzdr.de; Huang, L. G.; Metzkes, J.; Bussmann, M. [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany)] [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany); Gutt, C. [Universität Siegen, D-57068 Siegen (Germany)] [Universität Siegen, D-57068 Siegen (Germany); Schramm, U.; Cowan, T. E. [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany) [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany); Technische Universität Dresden, D-01062 Dresden (Germany)

    2014-03-15

    We demonstrate the potential of X-ray free-electron lasers (XFEL) to advance the understanding of complex plasma dynamics by allowing for the first time nanometer and femtosecond resolution at the same time in plasma diagnostics. Plasma phenomena on such short timescales are of high relevance for many fields of physics, in particular in the ultra-intense ultra-short laser interaction with matter. Highly relevant yet only partially understood phenomena become directly accessible in experiment. These include relativistic laser absorption at solid targets, creation of energetic electrons and electron transport in warm dense matter, including the seeding and development of surface and beam instabilities, ambipolar expansion, shock formation, and dynamics at the surfaces or at buried layers. In this paper, we focus on XFEL plasma probing for high power laser matter interactions based on quantitative calculations using synthesized data and evaluate the feasibility of various imaging and scattering techniques with special focus on the small angle X-ray scattering technique.

  15. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Faenov, A. Ya.; Colgan, J.; Hansen, S. B.; Zhidkov, A.; Pikuz, T. A.; Nishiuchi, M.; Pikuz, S. A.; Skobelev, I. Yu.; Abdallah, J.; Sakaki, H.; et al

    2015-09-02

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 1021 W/cm2 is efficiently converted to X-ray radiation, which is emitted by “hot” electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4–5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in thismore »regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017 W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. As a result, femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems.« less

  16. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser

    SciTech Connect (OSTI)

    Faenov, A. Ya.; Colgan, J.; Hansen, S. B.; Zhidkov, A.; Pikuz, T. A.; Nishiuchi, M.; Pikuz, S. A.; Skobelev, I. Yu.; Abdallah, J.; Sakaki, H.; Sagisaka, A.; Pirozhkov, A. S.; Ogura, K.; Fukuda, Y.; Kanasaki, M.; Hasegawa, N.; Nishikino, M.; Kando, M.; Watanabe, Y.; Kawachi, T.; Masuda, S.; Hosokai, T.; Kodama, R.; Kondo, K.

    2015-09-02

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 1021 W/cm2 is efficiently converted to X-ray radiation, which is emitted by “hot” electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4–5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017 W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. As a result, femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems.

  17. Characteristic x-ray emission from undermines plasmas irradiated by ultra-intense lasers

    SciTech Connect (OSTI)

    Niemann, Christoph

    2012-05-05

    Between FY09 and FY11 we have conducted more than a dozen three-week experimental campaigns at high-power laser facilities around the world to investigate laser-channeling through x-ray and optical imaging and the conversion from laser-energy to xrays. We have performed simultaneous two-wavelength x-ray imaging (K-alpha and He-alpha) to distinguish the hot-plasma region (hot-spot) from the laser-produced electrons (K-alpha). In addition, we have initiated a new collaboration with SNL and have performed first shots on the 100 TW beamlet chamber to commission a fast x-ray streak camera to be used to investigate the temporal evolution of our K-alpha sources. We also collaborated on campaigns at the Rutherford Appleton Laboratory (UK) and the LANL Trident laser to employ laser produced x-ray sources for Thomson scattering off dense matter.

  18. Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses

    SciTech Connect (OSTI)

    Jahangiri, Fazel [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Department of Physics, GSS, Kyoto University, Kyoto (Japan); Nagashima, Takeshi; Hangyo, Masanori [Department of Physics, GSS, Kyoto University, Kyoto (Japan) [Department of Physics, GSS, Kyoto University, Kyoto (Japan); Institute of Laser Engineering, Osaka University, Osaka (Japan)

    2013-05-13

    Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.

  19. Steering proton migration in hydrocarbons using intense few-cycle laser fields

    E-Print Network [OSTI]

    Kübel, M; Burger, C; Kling, Nora G; Li, H; Alnaser, A S; Bergues, B; Zherebtsov, S; Azzeer, A M; Ben-Itzhak, I; Moshammer, R; de Vivie-Riedle, R; Kling, M F

    2015-01-01

    Proton migration is a ubiquitous process in chemical reactions related to biology, combustion, and catalysis. Thus, the ability to control the movement of nuclei with tailored light, within a hydrocarbon molecule holds promise for far-reaching applications. Here, we demonstrate the steering of hydrogen migration in simple hydrocarbons, namely acetylene and allene, using waveform-controlled, few-cycle laser pulses. The rearrangement dynamics are monitored using coincident 3D momentum imaging spectroscopy, and described with a quantum-dynamical model. Our observations reveal that the underlying control mechanism is due to the manipulation of the phases in a vibrational wavepacket by the intense off-resonant laser field.

  20. Intensity-resolved ionization yields of aniline with femtosecond laser pulses

    SciTech Connect (OSTI)

    Strohaber, J.; Hart, N.; Zhu, F.; Nava, R.; Pham, F.; Kolomenskii, A. A.; Paulus, G. G.; Schuessler, H. A.; Mohamed, T.; Schroeder, H.

    2011-12-15

    We present experimental results for the ionization of aniline and benzene molecules subjected to intense ultrashort laser pulses. Measured parent molecular ions yields were obtained using a recently developed technique capable of three-dimensional imaging of ion distributions within the focus of a laser beam. By selecting ions originating from the central region of the focus, where the spatial intensity distribution is nearly uniform, volumetric-free intensity-dependent ionization yields were obtained. The measured data revealed a previously unseen resonance-enhanced multiphoton ionization (REMPI)-like process. Comparison of benzene, aniline, and Xe ion yields demonstrates that the observed intensity-dependent structures are not due to geometric artifacts in the focus. Finally for intensities greater than {approx}3x10{sup 13} W/cm{sup 2}, we attribute the ionization of aniline to a stepwise process going through the {pi}{sigma}{sup *} state which sits three photons above the ground state and two photons below the continuum.

  1. New photon science and extreme field physics: volumetric interaction of ultra-intense laser pulses with over-dense targets

    SciTech Connect (OSTI)

    Hegelich, Bjorn M [Los Alamos National Laboratory

    2010-11-24

    The constantly improving capabilities of ultra-high power lasers are enabling interactions of matter with ever extremer fields. As both the on target intensity and the laser contrast are increasing, new physics regimes are becoming accessible and new effects materialize, which in turn enable a host of applications. A first example is the realization of interactions in the transparent-overdense regime (TOR), which is reached by interacting a highly relativistic (a{sub 0} > 10), ultra high contrast laser pulse with a solid density, nanometer target. Here, a still overdense target is turned transparent to the laser by the relativistic mass increase of the electrons, increasing the skin depth beyond the target thickness and thus enabling volumetric interaction of the laser with the entire target instead of only a small interaction region at the critical density surface. This increases the energy coupling, enabling a range of effects, including relativistic optics and pulse shaping, mono-energetic electron acceleration, highly efficient ion acceleration in the break-out afterburner regime, the generation of relativistic and forward directed surface harmonics. In this talk we will show the theoretical framework for this regime, explored by multi-D, high resolution and high density PIC simulations as well as analytic theory and present measurements and experimental demonstrations of direct relativistic optics, relativistic HHG, electron acceleration, and BOA ion acceleration in the transparent overdense regime. These effects can in turn be used in a host of applications including laser pulse shaping, ICF diagnostics, coherent x-ray sources, and ion sources for fast ignition (IFI), homeland security applications and medical therapy. This host of applications already makes transparent-overdense regime one of general interest, a situation reinforced by the fact that the TOR target undergoes an extremely wide HEDP parameter space during interaction ranging from WDM conditions (e.g . brown dwarfs) early in the interaction to extremely high energy densities of {approx}10{sup 11} J/cm{sup 3} at peak, dropping back to the underdense but extremely hot parameter range of gamma-ray bursts. Furthermore, whereas today this regime can only be accessed on very few dedicated facilities, employing special targets and pulse cleaning technology, the next generation of laser facilities like RAL-10PW, ELI, or Gekko-Exa will operate in this regime by default, turning its understanding in a necessity rather than a curiosity.

  2. System and method that suppresses intensity fluctuations for free space high-speed optical communication

    DOE Patents [OSTI]

    Berman, Gennady P. (Los Alamos, NM); Bishop, Alan R. (Los Alamos, NM); Nguyen, Dinh C. (Los Alamos, NM); Chernobrod, Boris M. (Santa Fe, NM); Gorshkov, Vacheslav N. (Kiev, UA)

    2009-10-13

    A high-speed (Gbps), free space optical communication system is based on spectral encoding of radiation from a wide band light source, such as a laser. By using partially coherent laser beams in combination with a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km. To suppress the intensity fluctuations due to atmospheric turbulence, a source with partial transverse coherence in combination with slow response time photodetector is used. Information is encoded in the spectral domain of a wideband optical source by modulation of spectral amplitudes. A non-coherent light source with wide spectrum (an LED, for example) may be used for high-speed communication over short (less than about a mile) distances.

  3. Light scattering from laser induced pit ensembles on high power laser optics

    SciTech Connect (OSTI)

    Feigenbaum, Eyal [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Elhadj, Selim [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matthews, Manyalibo J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-01

    Far-field light scattering characteristics from randomly arranged shallow Gaussian-like shaped laser induced pits, found on optics exposed to high energy laser pulses, is studied. Closed-form expressions for the far-field intensity distribution and scattered power are derived for individual pits and validated using numerical calculations of both Fourier optics and FDTD solutions to Maxwell’s equations. It is found that the scattered power is proportional to the square of the pit width and approximately also to the square of the pit depth, with the proportionality factor scaling with pit depth. As a result, the power scattered from shallow pitted optics is expected to be substantially lower than assuming complete scattering from the total visible footprint of the pits.

  4. Light scattering from laser induced pit ensembles on high power laser optics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Feigenbaum, Eyal; Elhadj, Selim; Matthews, Manyalibo J.

    2015-01-01

    Far-field light scattering characteristics from randomly arranged shallow Gaussian-like shaped laser induced pits, found on optics exposed to high energy laser pulses, is studied. Closed-form expressions for the far-field intensity distribution and scattered power are derived for individual pits and validated using numerical calculations of both Fourier optics and FDTD solutions to Maxwell’s equations. It is found that the scattered power is proportional to the square of the pit width and approximately also to the square of the pit depth, with the proportionality factor scaling with pit depth. As a result, the power scattered from shallow pitted optics is expectedmore »to be substantially lower than assuming complete scattering from the total visible footprint of the pits.« less

  5. High Intensity Muon Beams in Osaka -MuSIC

    E-Print Network [OSTI]

    McDonald, Kirk

    High Intensity Muon Beams in Osaka - MuSIC Yoshitaka Kuno Osaka Unviersity, Osaka, Japan ! THB2014 ·Muon Transport ·COMET ·MuSIC facility at Osaka University ·MuSIC stage-I for µSR ·PRISM demonstration at MuSIC ·Phase Rotation at FFAG ·Summary #12;Muon Beam Sources #12;ISIS EM, RIKEN-RAL J-PARC, MUSE

  6. Drift tube suspension for high intensity linear accelerators

    DOE Patents [OSTI]

    Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

    1980-03-11

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

  7. A high-intensity, pulsed supersonii:, carbon source aivith C("Pi> kinetic energies of 0.08-0.7 eV for crossed beam experiments

    E-Print Network [OSTI]

    Kaiser, Ralf I.

    1 A high-intensity, pulsed supersonii:, carbon source aivith C("Pi> kinetic energies of 0.08-0.7 e the laser pulse, the pulsed valve, and a chopper wheel located 40 mm after the laser ablation. Neither. INTRODUCTION Chemical reactions of ground state atomic carbon C(3Pj) play a major role in combustion processes

  8. 5.5-7.5 MeV Proton Generation by a Moderate-Intensity Ultrashort-Pulse Laser Interaction with H{sub 2}O Nanowire Targets

    SciTech Connect (OSTI)

    Zigler, A.; Palchan, T.; Bruner, N.; Schleifer, E.; Eisenmann, S.; Botton, M.; Henis, Z. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Pikuz, S. A.; Faenov, A. Y. Jr. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation); Gordon, D.; Sprangle, P. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2011-04-01

    We report on the first generation of 5.5-7.5 MeV protons by a moderate-intensity short-pulse laser ({approx}5x10{sup 17} W/cm{sup 2}, 40 fsec) interacting with frozen H{sub 2}O nanometer-size structure droplets (snow nanowires) deposited on a sapphire substrate. In this setup, the laser intensity is locally enhanced by the snow nanowire, leading to high spatial gradients. Accordingly, the nanoplasma is subject to enhanced ponderomotive potential, and confined charge separation is obtained. Electrostatic fields of extremely high intensities are produced over the short scale length, and protons are accelerated to MeV-level energies.

  9. Towards phasing using high X-ray intensity

    SciTech Connect (OSTI)

    Galli, Lorenzo; Son, Sang -Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sébastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; Nass, Karol; Shoeman, Robert L.; Timneanu, Nicusor; Santra, Robin; Schlichting, Ilme; Chapman, Henry N.

    2015-09-30

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. In conclusion, a pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.

  10. Towards phasing using high X-ray intensity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Galli, Lorenzo; Son, Sang -Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sébastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; et al

    2015-09-30

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. In conclusion, a pattern sorting schememore »is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.« less

  11. High intensity proton operation at the Brookhaven AGS accelerator complex

    SciTech Connect (OSTI)

    Ahrens, L.A.; Blaskiewicz, M.; Bleser, E.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Onillon, E.; Reece, R.K.; Roser, T.; Soukas, A.

    1994-08-01

    With the completion of the AGS rf upgrade, and the implementation of a transition {open_quotes}jump{close_quotes}, all of accelerator systems were in place in 1994 to allow acceleration of the proton intensity available from the AGS Booster injector to AGS extraction energy and delivery to the high energy users. Beam commissioning results with these new systems are presented. Progress in identifying and overcoming other obstacles to higher intensity are given. These include a careful exploration of the stopband strengths present on the AGS injection magnetic porch, and implementation of the AGS single bunch transverse dampers throughout the acceleration cycle.

  12. Pulsed laser deposition with a high average power free electron laser: Benefits of subpicosecond pulses with high repetition rate

    E-Print Network [OSTI]

    Reilly, Anne

    Pulsed laser deposition with a high average power free electron laser: Benefits of subpicosecond 2002 We have conducted experiments exploring pulsed laser deposition of thin films using the high average power Thomas Jefferson National Accelerator Facility Free Electron Laser. The combination

  13. The influence of laser pulse duration and energy on ICP-MS signal intensity, elemental fractionation, and

    E-Print Network [OSTI]

    Harilal, S. S.

    of the thermal processes, heating of the sample can result in preferential evaporation, melting, and ablationThe influence of laser pulse duration and energy on ICP-MS signal intensity, elemental width, irradiance, repetition rate, and pulse energy, are critical parameters which influence the laser

  14. 1738 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 4, AUGUST 2008 Propagation of a Short Intense Laser Pulse

    E-Print Network [OSTI]

    Strathclyde, University of

    Intense Laser Pulse in a Curved Plasma Channel Albert Reitsma and Dino Jaroszynski Abstract--In this paper laser light. If there is a perfect balance between the inward bending of light rays through the light along a curved path by bending the waveguide. Light bending in a plasma waveguide has been

  15. Coherent beam combiner for a high power laser

    DOE Patents [OSTI]

    Dane, C. Brent (Livermore, CA); Hackel, Lloyd A. (Livermore, CA)

    2002-01-01

    A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

  16. Efficient electronic structure calculation for molecular ionization dynamics at high x-ray intensity

    E-Print Network [OSTI]

    Hao, Yajiang; Hanasaki, Kota; Son, Sang-Kil; Santra, Robin

    2015-01-01

    We present the implementation of an electronic-structure approach dedicated to ionization dynamics of molecules interacting with x-ray free-electron laser (XFEL) pulses. In our scheme, molecular orbitals for molecular core-hole states are represented by linear combination of numerical atomic orbitals that are solutions of corresponding atomic core-hole states. We demonstrate that our scheme efficiently calculates all possible multiple-hole configurations of molecules formed during XFEL pulses. The present method is suitable to investigate x-ray multiphoton multiple ionization dynamics and accompanying nuclear dynamics, providing essential information on the chemical dynamics relevant for high-intensity x-ray imaging.

  17. Phosphate glass useful in high energy lasers

    DOE Patents [OSTI]

    Hayden, Y.T.; Payne, S.A.; Hayden, J.S.; Campbell, J.H.; Aston, M.K.; Elder, M.L.

    1996-06-11

    In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

  18. Phosphate glass useful in high energy lasers

    DOE Patents [OSTI]

    Hayden, Yuiko T. (Clarks Summit, PA); Payne, Stephen A. (Castro Valley, CA); Hayden, Joseph S. (Clarks Summit, PA); Campbell, John H. (Livermore, CA); Aston, Mary Kay (Moscow, PA); Elder, Melanie L. (Dublin, CA)

    1996-01-01

    In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

  19. Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF

    SciTech Connect (OSTI)

    Ma, T

    2010-04-21

    The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

  20. Laser for high frequency modulated interferometry

    DOE Patents [OSTI]

    Mansfield, D.K.; Vocaturo, M.; Guttadora, L.J.

    1991-07-23

    A Stark-tuned laser operating in the 119 micron line of CH[sub 3]OH has an output power of several tens of milliwatts at 30 Watts of pump power while exhibiting a doublet splitting of about ten MHz with the application of a Stark field on the order of 500 volts/cm. This output power allows for use of the laser in a multi-channel interferometer, while its high operating frequency permits the interferometer to measure rapid electron density changes in a pellet injected or otherwise fueled plasma such as encountered in magnetic fusion devices. The laser includes a long far-infrared (FIR) pyrex resonator tube disposed within a cylindrical water jacket and incorporating charged electrodes for applying the Stark field to a gas confined therein. With the electrodes located within the resonator tube, the resonator tube walls are cooled by a flowing coolant without electrical breakdown in the coolant liquid during application of the Stark field. Wall cooling allows for substantially increased FIR output powers. Provision is made for introducing a buffer gas into the resonator tube for increasing laser output power and its operating bandwidth. 10 figures.

  1. Laser for high frequency modulated interferometry

    DOE Patents [OSTI]

    Mansfield, Dennis K. (E. Windsor, NJ); Vocaturo, Michael (Columbus, NJ); Guttadora, Lawrence J. (Iselin, NJ)

    1991-01-01

    A Stark-tuned laser operating in the 119 micron line of CH.sub.3 OH has an output power of several tens of milliwatts at 30 Watts of pump power while exhibiting a doublet splitting of about ten MHz with the application of a Stark field on the order of 500 volts/cm. This output power allows for use of the laser in a multi-channel interferometer, while its high operating frequency permits the interferometer to measure rapid electron density changes in a pellet injected or otherwise fueled plasma such as encountered in magnetic fusion devices. The laser includes a long far-infrared (FIR) pyrex resonator tube disposed within a cylindrical water jacket and incorporating charged electrodes for applying the Stark field to a gas confined therein. With the electrodes located within the resonator tube, the resonator tube walls are cooled by a flowing coolant without electrical breakdown in the coolant liquid during application of the Stark field. Wall cooling allows for substantially increased FIR output powers. Provision is made for introducing a buffer gas into the resonator tube for increasing laser output power and its operating bandwidth.

  2. Prolific pair production with high-power lasers

    E-Print Network [OSTI]

    Bell, A R

    2008-01-01

    Prolific electron-positron pair production is possible at laser intensities approaching 10^{24} W/cm^2 at a wavelength of 1 micron. An analysis of electron trajectories and interactions at the nodes (B=0) of two counter-propagating, circularly polarised laser beams shows that a cascade of gamma-rays and pairs develops. The geometry is generalised qualitatively to linear polarisation and laser beams incident on a solid target.

  3. Prolific pair production with high-power lasers

    E-Print Network [OSTI]

    A. R. Bell; John G. Kirk

    2008-10-16

    Prolific electron-positron pair production is possible at laser intensities approaching 10^{24} W/cm^2 at a wavelength of 1 micron. An analysis of electron trajectories and interactions at the nodes (B=0) of two counter-propagating, circularly polarised laser beams shows that a cascade of gamma-rays and pairs develops. The geometry is generalised qualitatively to linear polarisation and laser beams incident on a solid target.

  4. High-Power Solid-State Lasers from a Laser Glass Perspective

    SciTech Connect (OSTI)

    Campbell, J H; Hayden, J S; Marker, A J

    2010-12-17

    Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.

  5. High-intensity positron microprobe at Jefferson Lab

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Golge, Serkan; Vlahovic, Branislav; Wojtsekhowski, Bogdan B.

    2014-06-19

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of themore »beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.« less

  6. High-intensity positron microprobe at Jefferson Lab

    SciTech Connect (OSTI)

    Golge, Serkan; Vlahovic, Branislav; Wojtsekhowski, Bogdan B.

    2014-06-19

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.

  7. High-intensity positron microprobe at Jefferson Lab

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Golge, Serkan [North Carolina Central Univ., Durham, NC (United States); Vlahovic, Branislav [North Carolina Central Univ., Durham, NC (United States); Wojtsekhowski, Bogdan B. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2014-06-21

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.

  8. Strong-Field QED and High Power Lasers

    E-Print Network [OSTI]

    Thomas Heinzl

    2011-11-22

    This contribution presents an overview of fundamental QED processes in the presence of an external field produced by an ultra-intense laser. The discussion focusses on the basic intensity effects on vacuum polarisation and the prospects for their observation. Some historical remarks are added where appropriate.

  9. Adaptive RF Transient Reduction for HIGH Intensity Beams with Gaps

    E-Print Network [OSTI]

    Tückmantel, Joachim

    2006-01-01

    When a high-intensity beam with bunch-trains and gaps passes a cavity with a high-gain vector feedback enforcing a constant voltage, large transients appear, stressing the RF high power hardware and increasing the trip rate. By modulating the cavity voltage with a varying periodic waveform (set-function), the RF power can be made constant while still preserving the high feedback gain. The average cavity voltage is conserved but bunches have to settle at slightly shifted positions. A method is derived to obtain this set-function in practice while making no assumptions or measurements of the beam or RF parameters. Adiabatic iterations are made including the whole machine as an analog computing device, using all parameters as they are. A computer simulation shows the success of the method.

  10. High energy femtosecond fiber laser at 1018 nm and high power Cherenkov radiation generation

    E-Print Network [OSTI]

    Yang, Hongyu, S.M. Massachusetts Institute of Technology

    2014-01-01

    Two novel laser systems for ultrafast applications have been designed and built. For the seeding of a high energy cryogenically cooled Yb:YLF laser, a novel 1018 nm fiber laser system is demonstrated. It produces >35 nJ ...

  11. Physics of laser fusion. Volume IV. The future development of high-power solid-state laser systems

    SciTech Connect (OSTI)

    Emmett, J.L.; Krupke, W.F.; Trenholme, J.B.

    1982-11-01

    Solid state lasers, particularly neodymium glass systems, have undergone intensive development during the last decade. In this paper, we review solid state laser technology in the context of high-peak-power systems for inertial confinement fusion. Specifically addressed are five major factors: efficiency, wavelength flexibility, average power, system complexity, and cost; these factors today limit broader application of the technology. We conclude that each of these factors can be greatly improved within current fundamental physical limits. We further conclude that the systematic development of new solid state laser madia, both vitreous and crystalline, should ultimately permit the development of wavelength-flexible, very high average power systems with overall efficiencies in the range of 10 to 20%.

  12. Generation of high-energy-density ion bunches by ultraintense laser-cone-target interaction

    SciTech Connect (OSTI)

    Yang, X. H.; Zhuo, H. B., E-mail: hongbin.zhuo@gmail.com; Ma, Y. Y.; Zou, D. B.; Yu, T. P.; Ge, Z. Y.; Yin, Y.; Shao, F. Q. [College of Science, National University of Defense Technology, Changsha 410073 (China); Yu, W. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Xu, H., E-mail: xuhanemail@gmail.com [State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073 (China); Borghesi, M., E-mail: m.borghesi@qub.ac.uk [School of Mathematics and Physics, Queen's University of Belfast, Belfast BT7 1NN (United Kingdom); Institute of Physics of the ASCR, ELI-Beamlines Project, Na Slovance 2, 18221 Prague (Czech Republic)

    2014-06-15

    A scheme in which carbon ion bunches are accelerated to a high energy and density by a laser pulse (?10{sup 21}?W/cm{sup 2}) irradiating cone targets is proposed and investigated using particle-in-cell simulations. The laser pulse is focused by the cone and drives forward an ultrathin foil located at the cone's tip. In the course of the work, best results were obtained employing target configurations combining a low-Z cone with a multispecies foil transversely shaped to match the laser intensity profile.

  13. High power laser workover and completion tools and systems

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-10-28

    Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

  14. Generation of high pressure shocks relevant to the shock-ignition intensity regime

    SciTech Connect (OSTI)

    Batani, D.; Folpini, G.; Giuffrida, L.; Maheut, Y.; Malka, G.; Nicolai, Ph.; Ribeyre, X. [Université Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, F-33405 Talence (France)] [Université Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, F-33405 Talence (France); Antonelli, L. [Université Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, F-33405 Talence (France) [Université Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, F-33405 Talence (France); Universitą di Roma “Tor Vergata,” Roma (Italy); Atzeni, S.; Marocchino, A.; Schiavi, A. [Dipartimento SBAI, Université di Roma “La Sapienza” and CNISM, Roma (Italy)] [Dipartimento SBAI, Université di Roma “La Sapienza” and CNISM, Roma (Italy); Badziak, J.; Chodukowski, T.; Kalinowska, Z.; Pisarczyk, T.; Rosinski, M. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland)] [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Baffigi, F.; Cristoforetti, G.; Gizzi, L. A.; Koester, P. [Intense Laser Irradiation Laboratory, INO-CNR, Pisa (Italy)] [Intense Laser Irradiation Laboratory, INO-CNR, Pisa (Italy); and others

    2014-03-15

    An experiment was performed using the PALS laser to study laser-target coupling and laser-plasma interaction in an intensity regime ?10{sup 16}?W/cm{sup 2}, relevant for the “shock ignition” approach to Inertial Confinement Fusion. A first beam at low intensity was used to create an extended preformed plasma, and a second one to create a strong shock. Pressures up to 90 Megabars were inferred. Our results show the importance of the details of energy transport in the overdense region.

  15. Radiation Dose Measurement for High-Intensity Laser Interactions...

    Office of Scientific and Technical Information (OSTI)

    Org: SLAC National Accelerator Laboratory (SLAC) Sponsoring Org: US DOE Office of Science (DOE SC) Country of Publication: United States Language: English Subject: OPTICS, SAFETY...

  16. High-Powered Lasers for Clean Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you notHeat Pumps Heat Pumps An error occurred. Try|High-Powered Lasers

  17. Overview of High Intensity Linac Programs in Europe

    E-Print Network [OSTI]

    Garoby, R

    2004-01-01

    Recent years have seen a boost in the support by the European Union (EU) of accelerator research in Europe. Provided they coordinate their efforts and define common goals and strategies, laboratories and institutions from the member states can receive a financial support reaching 50% of the total project cost. In the field of High Intensity Linacs, the EU has already supported the EURISOL initiative for nuclear physics, which this year is applying for funding of a Design Study, and the development of linacs for Waste Transmutation. More recently, an initiative for high-energy physics has been approved, which includes a programme for the development of pulsed linac technologies. The coordination and synergy imposed by the EU rules increase the benefit of the allocated resources. Combined with the ongoing internal projects in the partner laboratories, these European initiatives represent a strong effort focussed towards the development of linac technologies. This paper summarises the requests from the various E...

  18. Ultra-High Intensity Magnetic Field Generation in Dense Plasma

    SciTech Connect (OSTI)

    Fisch, Nathaniel J

    2014-01-08

    I. Grant Objective The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereasthefficient generation of electric current in low-­?energy-­? density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­?energy-­? density plasma the ideas for steady-­?state current drive developed for low-­?energy-­? density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­?energy-­?density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

  19. Ultrafast laser ablation ICP-MS: role of spot size, laser fluence, and repetition rate in signal intensity

    E-Print Network [OSTI]

    Harilal, S. S.

    Ultrafast laser ablation ICP-MS: role of spot size, laser fluence, and repetition rate in signal,a Richard E. Russob and Ahmed Hassaneina Ultrafast laser ablation inductively coupled plasma mass system. Though ultrafast laser ablation sample introduction provides better accuracy and precision

  20. Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bang, W.

    2015-07-02

    Energetic deuterium ions from large deuterium clusters (>10 nm diameter) irradiated by an intense laser pulse (>10¹? W/cm²) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We show an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the availablemore »experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10 - keV deuterium fusion plasma for 10 ns.« less

  1. Waveguide CO{sub 2} laser with a quasi-homogeneous distribution of the output radiation intensity

    SciTech Connect (OSTI)

    Vlasenko, S A; Gurin, O V; Degtyarev, A V; Maslov, Vyacheslav A; Svich, V A; Topkov, A N

    2013-05-31

    An experimental sample of a waveguide CO{sub 2} laser with a quasi-uniform profile of the output radiation intensity is designed on the basis of a waveguide quasi-optical cavity of a new type comprising the generic confocal cavity with a nonuniform mirror and the hollow waveguide with the dimensions satisfying the conditions for self-imaging the quasi-uniform field. The surface of the mirror has the discrete large-scale absorbing nonuniformities. Results of theoretical and experimental investigations of spatial-energy characteristics of the laser in using uniform or amplitude-stepped reflecting mirrors are presented. (lasers)

  2. Characterization of proton and heavier ion acceleration in ultrahigh-intensity laser interactions with heated target foils

    SciTech Connect (OSTI)

    McKenna, P.; Ledingham, K.W.D.; Yang, J.M.; Robson, L.; McCanny, T.; Shimizu, S.; Clarke, R.J.; Neely, D.; Norreys, P.A.; Spohr, K.; Chapman, R.; Singhal, R.P.; Krushelnick, K.; Wei, M.S.

    2004-09-01

    Proton and heavy ion acceleration in ultrahigh intensity ({approx}2x10{sup 20} W cm{sup -2}) laser plasma interactions has been investigated using the new petawatt arm of the VULCAN laser. Nuclear activation techniques have been applied to make the first spatially integrated measurements of both proton and heavy ion acceleration from the same laser shots with heated and unheated Fe foil targets. Fe ions with energies greater than 10 MeV per nucleon have been observed. Effects of target heating on the accelerated ion energy spectra and the laser-to-ion energy conversion efficiencies are discussed. The laser-driven production of the long-lived isotope {sup 57}Co (271 days) via a heavy ion induced reaction is demonstrated.

  3. High average power scaleable thin-disk laser

    DOE Patents [OSTI]

    Beach, Raymond J. (Livermore, CA); Honea, Eric C. (Sunol, CA); Bibeau, Camille (Dublin, CA); Payne, Stephen A. (Castro Valley, CA); Powell, Howard (Livermore, CA); Krupke, William F. (Pleasanton, CA); Sutton, Steven B. (Manteca, CA)

    2002-01-01

    Using a thin disk laser gain element with an undoped cap layer enables the scaling of lasers to extremely high average output power values. Ordinarily, the power scaling of such thin disk lasers is limited by the deleterious effects of amplified spontaneous emission. By using an undoped cap layer diffusion bonded to the thin disk, the onset of amplified spontaneous emission does not occur as readily as if no cap layer is used, and much larger transverse thin disks can be effectively used as laser gain elements. This invention can be used as a high average power laser for material processing applications as well as for weapon and air defense applications.

  4. Highly Nonlinear Luminescence Induced by Gold Nanoparticles on Glass Surfaces with Continuous-Wave Laser Illumination

    E-Print Network [OSTI]

    Wu, Yong; Toro, Ligia; Stefani, Enrico

    2015-01-01

    We report on highly nonlinear luminescence being observed from individual spherical gold nanoparticles immobilized on a borosilicate glass surface and illuminated by continuous-wave (CW) lasers with relatively low power. The nonlinear luminescence shows optical super-resolution beyond the diffraction limit in three dimensions compared to the scatting of the excitation laser light. The luminescence intensity from most nanoparticles is proportional to the 5th--7th power of the excitation laser power and has wide excitation and emission spectra across the visible wavelength range. Strong nonlinear luminescence is only observed near the glass surface. High optical nonlinearity excited by low CW laser power is related to a long-lived dark state of the gold nanoparticles, where the excitation light is strongly absorbed. This phenomenon has potential biological applications in super-resolution and deep tissue imaging.

  5. High intensity neutrino source superconducting solenoid cyrostat design

    SciTech Connect (OSTI)

    Page, T.M.; Nicol, T.H.; Feher, S.; Terechkine, I.; Tompkins, J.; /Fermilab

    2006-06-01

    Fermi National Accelerator Laboratory (FNAL) is involved in the development of a 100 MeV superconducting linac. This linac is part of the High Intensity Neutrino Source (HINS) R&D Program. The initial beam acceleration in the front end section of the linac is achieved using room temperature spoke cavities, each of which is combined with a superconducting focusing solenoid. These solenoid magnets are cooled with liquid helium at 4.5K, operate at 250 A and have a maximum magnetic field strength of 7.5 T. The solenoid cryostat will house the helium vessel, suspension system, thermal shield, multilayer insulation, power leads, instrumentation, a vacuum vessel and cryogenic distribution lines. This paper discusses the requirements and detailed design of these superconducting solenoid cryostats.

  6. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in...

  7. High Power Laser Innovation Sparks Geothermal Power Potential...

    Energy Savers [EERE]

    project partner Foro Energy lab tests a high power laser tool with a patented technology that could maximize heat recovery from geothermal wells. Source: Foro Energy....

  8. High Power Laser Innovation Sparks Geothermal Power Potential...

    Broader source: Energy.gov (indexed) [DOE]

    Energy Department's project partner Foro Energy lab tests a high power laser tool with a patented technology that could maximize heat recovery from geothermal wells. Source: Foro...

  9. Generation of very low energy-spread electron beams using low-intensity laser pulses in a low-density plasma

    SciTech Connect (OSTI)

    Upadhyay, Ajay K.; Samant, Sushil Arun; Sarkar, Deepangkar; Krishnagopal, Srinivas; Jha, Pallavi

    2011-03-15

    The possibility of obtaining high-energy electron beams of high quality by using a low-density homogeneous plasma and a low-intensity laser (just above the self-injection threshold in the bubble regime) has been explored. Three-dimensional simulations are used to demonstrate, for the first time, an energy-spread of less than 1%, from self-trapping. More specifically, for a plasma density of 2x10{sup 18} cm{sup -3} and a laser intensity of a{sub 0}=2, a high-energy (0.55 GeV), ultrashort (1.4 fs) electron beam with very low energy-spread (0.55%) and high current (3 kA) is obtained. These parameters satisfy the requirements for drivers of short-wavelength free-electron lasers. It is also found that the quality of the electron beam depends strongly on the plasma length, which therefore needs to be optimized carefully to get the best performance in the experiments.

  10. Dimensional scaling treatment of stability of simple diatomic molecules induced by superintense, high-frequency laser fields

    E-Print Network [OSTI]

    Kais, Sabre

    , high-frequency laser fields Qi Wei,1 Sabre Kais,1,a and Dudley Herschbach2 1 Department of Chemistry 2008; published online 3 December 2008 We present results obtained using dimensional scaling with high-frequency as the radiation intensity increases.8 In the high-frequency regime, the time-dependent Schroedinger equation

  11. High power solid state laser modulator

    DOE Patents [OSTI]

    Birx, Daniel L.; Ball, Don G.; Cook, Edward G.

    2004-04-27

    A multi-stage magnetic modulator provides a pulse train of .+-.40 kV electrical pulses at a 5-7 kHz repetition rate to a metal vapor laser. A fractional turn transformer steps up the voltage by a factor of 80 to 1 and magnetic pulse compression is used to reduce the pulse width of the pulse train. The transformer is fabricated utilizing a rod and plate stack type of construction to achieve a high packing factor. The pulses are controlled by an SCR stack where a plurality of SCRs are electrically connected in parallel, each SCR electrically connected to a saturable inductor, all saturable inductors being wound on the same core of magnetic material for enhanced power handling characteristics.

  12. High power laser downhole cutting tools and systems

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-01-20

    Downhole cutting systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser cutting operations within a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform cutting operations in such boreholes deep within the earth.

  13. High degree of molecular orientation by a combination of THz and femtosecond laser pulses

    SciTech Connect (OSTI)

    Kitano, Kenta; Ishii, Nobuhisa; Itatani, Jiro [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan) and CREST, Japan Science and Technology Agency, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan)

    2011-11-15

    We propose a method for achieving molecular orientation by two-step excitation with intense femtosecond laser and terahertz (THz) pulses. First, the femtosecond laser pulse induces off-resonant impulsive Raman excitation to create rotational wave packets. Next, a delayed intense THz pulse effectively induces resonant dipole transition between neighboring rotational states. By controlling the intensities of both the pulses and the time delay, we can create rotational wave packets consisting of states with different parities in order to achieve a high degree of molecular orientation under a field-free condition. We numerically demonstrate that the highest degree of orientation of >0.8 in HBr molecules is feasible under experimentally available conditions.

  14. High energy heavy ion jets emerging from laser plasma generated by long pulse laser beams from

    E-Print Network [OSTI]

    High energy heavy ion jets emerging from laser plasma generated by long pulse laser beams from, Darmstadt, Germany 2 GSI, Darmstadt, Germany 3 Université de Provence et CNRS, Marseille, France 4, Albuquerque, New Mexico. ~Received 21 February 2005; Accepted 20 April 2005! Abstract High energy heavy ions

  15. Phosphate glass useful in high energy lasers

    DOE Patents [OSTI]

    Hayden, Y.T.; Guesto-Barnak, D.

    1992-12-22

    Disclosed is a low-or no-silica, low- or no-alkali phosphate glass useful as a laser amplifier in a multiple pass, high energy laser system having a high thermal conductivity, K[sub 90 C] >0.85 W/mK, a low coefficient of thermal expansion, [alpha][sub 20-300 C] <80[times]10[sup [minus]7]/C, low emission cross section, [sigma]<2.5[times]10[sup [minus]20] cm[sup 2], and a high fluorescence lifetime, [tau]>325 [mu]secs at 3 wt. % Nd doping, consisting essentially of (on an oxide composition basis): (Mole %) P[sub 2]O[sub 5], (52-72); Al[sub 2]O[sub 3], (0-<20); B[sub 2]O[sub 3], (>0-25); ZnO, (0-31); Li[sub 2]O, (0-5); K[sub 2]O, (0-5); Na[sub 2]O, (0-5); Cs[sub 2]O, (0-5); Rb[sub 2]O, (0-5); MgO, (>0-<30); CaO, (0-20); BaO, (0-20); SrO, (0-<20); Sb[sub 2]O[sub 3], (0-<1); As[sub 2]O[sub 3], (0-<1); Nb[sub 2]O[sub 5], (0-<1); Ln[sub 2]O[sub 3], (up to 6.5); PbO, (0-<5); and SiO[sub 2], (0-3); wherein Ln[sub 2]O[sub 3] is the sum of lanthanide oxides; [Sigma]R[sub 2]O is <5, R being Li, Na, K, Cs, and Rb; the sum of Al[sub 2]O[sub 3] and MgO is <24 unless [Sigma]R[sub 2]O is 0, then the sum of Al[sub 2]O[sub 3] and MgO is <42; and the ratio of MgO to B[sub 2]O[sub 3] is 0.48-4.20. 7 figs.

  16. Second user workshop on high-power lasers at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Heimann, Phil; Glenzer, Siegfried

    2015-05-28

    The second international workshop on the physics enabled by the unique combination of high-power lasers with the world-class Linac Coherent Light Source (LCLS) free-electron X-ray laser beam was held in Stanford, CA, on October 7–8, 2014. The workshop was co-organized by UC Berkeley, Lawrence Berkeley, Lawrence Livermore, and SLAC National Accelerator Laboratories. More than 120 scientists, including 40 students and postdoctoral scientists who are working in high-intensity laser-matter interactions, fusion research, and dynamic high-pressure science came together from North America, Europe, and Asia. The focus of the second workshop was on scientific highlights and the lessons learned from 16 newmore »experiments that were performed on the Matter in Extreme Conditions (MEC) instrument since the first workshop was held one year ago.« less

  17. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect (OSTI)

    Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2010-03-16

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  18. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect (OSTI)

    Bieniosek, F.M.; Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2008-08-01

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  19. Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms

    E-Print Network [OSTI]

    Toshiyuki Hosoya; Martin Miranda; Ryotaro Inoue; Mikio Kozuma

    2014-12-02

    We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system, which does not depend on complex nonlinear frequency-doubling, has great importance for implementing transportable optical lattice clocks, and is also useful for investigations on condensed matter physics or quantum information processing using cold atoms.

  20. 3D PIC simulations of electron beams created via reflection of intense laser light from a water target

    E-Print Network [OSTI]

    Ngirmang, Gregory K; Feister, Scott; Morrison, John T; Chowdhury, Enam A; Frische, Kyle; Roquemore, W M

    2015-01-01

    We present 3D Particle-in-Cell (PIC) modeling of an ultra-intense laser experiment by the Extreme Light group at the Air Force Research Laboratory (AFRL) using the PIC code LSP. This is the first time PIC simulations have been performed in 3D for this experiment which involves an ultra-intense, short-pulse (30 fs) laser interacting with a water jet target at normal incidence. These 3D PIC simulation results are compared to results from 2D(3$v$) PIC simulations for both $5.4\\cdot10^{17}$ W cm$^{-2}$ and $3\\cdot10^{18}$ W cm$^{-2}$ intensities. Comparing the 2D(3$v$) and 3D simulation results, the laser-energy-to-ejected-electron-energy conversion efficiencies were comparable, but the angular distribution of ejected electrons show interesting differences with qualitative differences at higher intensity. An analytic plane-wave model is provided that provides some explanation for the angular distribution and energies of ejected electrons in the 2D(3$v$) simulations. We also performed a 3D simulation with circular...

  1. A contactless microwave-based diagnostic tool for high repetition rate laser systems

    SciTech Connect (OSTI)

    Braggio, C., E-mail: caterina.braggio@unipd.it [Dip. di Fisica e Astronomia and INFN sez. di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Borghesani, A. F. [CNISM unit, Dip. di Fisica e Astronomia and INFN sez. di Padova, Via F. Marzolo 8, I-35131 Padova (Italy)] [CNISM unit, Dip. di Fisica e Astronomia and INFN sez. di Padova, Via F. Marzolo 8, I-35131 Padova (Italy)

    2014-02-15

    We report on a novel electro-optic device for the diagnostics of high repetition rate laser systems. It is composed of a microwave receiver and of a second order nonlinear crystal, whose irradiation with a train of short laser pulses produces a time-dependent polarization in the crystal itself as a consequence of optical rectification. This process gives rise to the emission of microwave radiation that is detected by a receiver and is analyzed to infer the repetition rate and intensity of the pulses. We believe that this new method may overcome some of the limitations of photodetection techniques.

  2. Vertical cavity surface-emitting laser scanning cytometer for high speed analysis of cells

    SciTech Connect (OSTI)

    Gourley, P.L.; McDonald, A.E.; Gourley, M.F.

    1995-12-31

    We have constructed a new semiconductor laser device that may be useful in high speed characterization of cell morphology for diagnosis of disease. This laser device has critical advantages over conventional cell fluorescence detection methods since it provides intense, monochromatic, low-divergence fight signals that are emitted from lasing modes confined by a cell. Further, the device integrates biological structures with semiconductor materials at the wafer level to reduce device size and simplify cell preparation. In this paper we discuss operational characteristics of the prototype cytometer and present preliminary data for blood cells and dielectric spheres.

  3. High harmonic generation in hydrogen and helium atoms subject to one{ and two{color laser pulses

    E-Print Network [OSTI]

    Gross, E.K.U.

    High harmonic generation in hydrogen and helium atoms subject to one{ and two{color laser pulses Surzburg Germany Abstract. We present simulations of harmonic generation in hydrogen and helium solving for the generation of intense high{order harmonics are discussed. 1. Introduction Since the discovery of harmonic

  4. High energy XeBr electric discharge laser

    DOE Patents [OSTI]

    Sze, Robert C. (Santa Fe, NM); Scott, Peter B. (Los Alamos, NM)

    1981-01-01

    A high energy XeBr laser for producing coherent radiation at 282 nm. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr is used as the halogen donor which undergoes harpooning reactions with Xe.sub.M * to form XeBr*.

  5. Channeling of microwave radiation in a double line containing a plasma filament produced by intense femtosecond laser pulses in air

    SciTech Connect (OSTI)

    Bogatov, N A; Kuznetsov, A I; Smirnov, A I; Stepanov, A N

    2009-10-31

    The channeling of microwave radiation is demonstrated experimentally in a double line in which a plasma filament produced in air by intense femtosecond laser pulses serves as one of the conductors. It is shown that during the propagation of microwave radiation in this line, ultrashort pulses are formed, their duration monotonically decreasing with increasing the propagation length (down to the value comparable with the microwave field period). These effects can be used for diagnostics of plasma in a filament. (laser applications and other topics in quantum electronics)

  6. Glass Strengthening via High-Intensity Plasma-Arc Heating

    SciTech Connect (OSTI)

    Wereszczak, Andrew A; Harper, David C; Duty, Chad E; Patel, P

    2010-01-01

    The use of a high-intensity plasma-arc lamp was used to irradiate the surface of soda-lime silicate glass tiles to determine if an increase in strength could be achieved. The lamp had a power density of 3500 W/cm2, a processing area of 1 cm x 10 cm, irradiated near-infrared heating at a wavelength between 0.2 1.4 m, and was controlled to unidirectionally sweep across 50-mm-square tiles at a constant speed of 8 mm/s. Ring-on-ring (RoR) equibiaxial flexure and 4 pt uni-directional flexure testings of entire tiles were used to measure and compare failure stress distributions of treated and untreated glass. Even with non-optimized processing conditions, RoR failure stress increased by approximately 25% and the 4 pt bend failure stress increased by approximately 65%. Strengthening was due to a fire-polishing-like mechanism. The arc-lamp heat-treatment caused the location of the strength-limiting flaws in the 4-pt-bend tiles to change; namely, failure initiation occurred on the gage section surface for the treated glass whereas it occurred at a gage section edge for the untreated. Arc-lamp heat-treatment is attractive not only because it provides strengthening, but because it can (non-contact) process large amounts of glass quickly and inexpensively, and is a process that either a glass manufacturer or end-user can readily employ.

  7. Target isolation system, high power laser and laser peening method and system using same

    DOE Patents [OSTI]

    Dane, C. Brent (Livermore, CA); Hackel, Lloyd A. (Livermore, CA); Harris, Fritz (Rocklin, CA)

    2007-11-06

    A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

  8. The High Average Power Laser Program 15th HAPL meeting

    E-Print Network [OSTI]

    , 2006 #12;2 The HAPL team is developing the science, technology and architecture needed for a laser1 The High Average Power Laser Program 15th HAPL meeting Aug 8 & 9, 2006 General Atomics Scientific Inst 16. Optiswitch Technology 17. ESLI Electricity Generator Electricity Generator Reaction

  9. Device for wavefront correction in an ultra high power laser

    DOE Patents [OSTI]

    Ault, Earl R. (Livermore, CA); Comaskey, Brian J. (Walnut Creek, CA); Kuklo, Thomas C. (Oakdale, CA)

    2002-01-01

    A system for wavefront correction in an ultra high power laser. As the laser medium flows past the optical excitation source and the fluid warms its index of refraction changes creating an optical wedge. A system is provided for correcting the thermally induced optical phase errors.

  10. Master-Oscillator-Power-Amplifier (MOPA) Laser Sources Used as Drive Lasers for Photoinjectors for High-Gain, Free Electron Lasers (FELs)

    E-Print Network [OSTI]

    Anlage, Steven

    Master-Oscillator-Power-Amplifier (MOPA) Laser Sources Used as Drive Lasers for Photoinjectors Milchberg #12;- 1 - Abstract The realization of extremely high gain, and high power in Free Electron Lasers critically on the power and phase stability of the cathode drive laser, and conversely the type of FEL output

  11. Increasing the upper-limit intensity and temperature range for thermal self-focusing of a laser beam by using plasma density ramp-up

    SciTech Connect (OSTI)

    Bokaei, B.; Niknam, A. R.

    2014-03-15

    This work is devoted to improving relativistic and ponderomotive thermal self-focusing of the intense laser beam in an underdense plasma. It is shown that the ponderomotive nonlinearity induces a saturation mechanism for thermal self-focusing. Therefore, in addition to the well-known lower-limit critical intensity, there is an upper-limit intensity for thermal self-focusing above which the laser beam starts to experience ponderomotive defocusing. It is indicated that the upper-limit intensity value is dependent on plasma and laser parameters such as the plasma electron temperature, plasma density, and laser spot size. Furthermore, the effect of the upward plasma density ramp profile on the thermal self-focusing is studied. Results show that by using the plasma density ramp-up, the upper-limit intensity increases and the self-focusing temperature range expands.

  12. Microjet formation and hard x-ray production from a liquid metal target irradiated by intense femtosecond laser pulses

    SciTech Connect (OSTI)

    Lar'kin, A. Uryupina, D.; Ivanov, K.; Savel'ev, A.; Bonnet, T.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Spohr, K.; Breil, J.; Chimier, B.; Dorchies, F.; Fourment, C.; Leguay, P.-M.; Tikhonchuk, V. T.

    2014-09-15

    By using a liquid metal as a target one may significantly enhance the yield of hard x-rays with a sequence of two intense femtosecond laser pulses. The influence of the time delay between the two pulses is studied experimentally and interpreted with numerical simulations. It was suggested that the first arbitrary weak pulse produces microjets from the target surface, while the second intense pulse provides an efficient electron heating and acceleration along the jet surface. These energetic electrons are the source of x-ray emission while striking the target surface. The microjet formation is explained based on the results given by both optical diagnostics and hydrodynamic modeling by a collision of shocks originated from two distinct zones of laser energy deposition.

  13. Upper limit power for self-guided propagation of intense lasers in plasma

    SciTech Connect (OSTI)

    Wang Weimin; Hu Zhidan; Chen Liming; Li Yutong; Sheng Zhengming; Zhang Jie; Zeng Ming; Liu Yue; Kawata, Shigeo; Zheng Chunyang; Mori, Warren B.

    2012-10-29

    It is shown that there is an upper-limit laser power for self-focusing of a laser pulse in plasma in addition to the well-known lower-limit critical power set by the relativistic effect. This upper limit is caused by the transverse ponderomotive force of the laser, which tends to expel plasma electrons from the laser propagating area. Furthermore, there is a lower-limit plasma density for a given laser spot size, below which self-focusing does not occur for any laser power. Both the lower-limit density and the upper-limit power are derived theoretically and verified by two-dimensional and three-dimensional particle-in-cell simulations. It is also found that plasma channels may be unfavorable for stable guiding of lasers above the upper-limit power.

  14. High-Energy Laser Diagnostics (HELD) for the Measurement of Diesel...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    High-Energy Laser Diagnostics (HELD) for the Measurement of Diesel Particulate Matter High-Energy Laser Diagnostics (HELD) for the Measurement of Diesel Particulate Matter 2004...

  15. Safety approaches for high power modular laser operation

    SciTech Connect (OSTI)

    Handren, R.T.

    1993-03-01

    Approximately 20 years ago, a program was initiated at the Lawrence Livermore National Laboratory (LLNL) to study the feasibility of using lasers to separate isotopes of uranium and other materials. Of particular interest has been the development of a uranium enrichment method for the production of commercial nuclear power reactor fuel to replace current more expensive methods. The Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program has progressed to the point where a plant-scale facility to demonstrate commercial feasibility has been built and is being tested. The U-AVLIS Program uses copper vapor lasers which pump frequency selective dye lasers to photoionize uranium vapor produced by an electron beam. The selectively ionized isotopes are electrostatically collected. The copper lasers are arranged in oscillator/amplifier chains. The current configuration consists of 12 chains, each with a nominal output of 800 W for a system output in excess of 9 kW. The system requirements are for continuous operation (24 h a day, 7 days a week) and high availability. To meet these requirements, the lasers are designed in a modular form allowing for rapid change-out of the lasers requiring maintenance. Since beginning operation in early 1985, the copper lasers have accumulated over 2 million unit hours at a >90% availability. The dye laser system provides approximately 2.5 kW average power in the visible wavelength range. This large-scale laser system has many safety considerations, including high-power laser beams, high voltage, and large quantities ({approximately}3000 gal) of ethanol dye solutions. The Laboratory`s safety policy requires that safety controls be designed into any process, equipment, or apparatus in the form of engineering controls. Administrative controls further reduce the risk to an acceptable level. Selected examples of engineering and administrative controls currently being used in the U-AVLIS Program are described.

  16. Enhanced water window x-ray emission from in situ formed carbon clusters irradiated by intense ultra-short laser pulses

    SciTech Connect (OSTI)

    Chakravarty, U.; Rao, B. S.; Arora, V.; Upadhyay, A.; Singhal, H.; Naik, P. A.; Chakera, J. A.; Mukherjee, C.; Gupta, P. D. [Raja Ramanna Centre for Advanced Technology, Indore, 452 013 Madhya Pradesh (India)] [Raja Ramanna Centre for Advanced Technology, Indore, 452 013 Madhya Pradesh (India)

    2013-07-29

    Enhanced water window x-ray emission (23–44 Å) from carbon clusters, formed in situ using a pre-pulse, irradiated by intense (I > 10{sup 17} W/cm{sup 2}) ultra-short laser pulse, is demonstrated. An order of magnitude x-ray enhancement over planar graphite target is observed in carbon clusters, formed by a sub-ns pre-pulse, interacting with intense main pulse after a delay. The effect of the delay and the duration of the main pulse is studied for optimizing the x-ray emission in the water window region. This x-ray source has added advantages of being an efficient, high repetition rate, and low debris x-ray source.

  17. The slingshot effect: A possible new laser-driven high energy acceleration mechanism for electrons

    SciTech Connect (OSTI)

    Fiore, Gaetano; Fedele, Renato; Angelis, Umberto de

    2014-11-15

    We show that under appropriate conditions the impact of a very short and intense laser pulse onto a plasma causes the expulsion of surface electrons with high energy in the direction opposite to the one of the propagations of the pulse. This is due to the combined effects of the ponderomotive force and the huge longitudinal field arising from charge separation (“slingshot effect”). The effect should also be present with other states of matter, provided the pulse is sufficiently intense to locally cause complete ionization. An experimental test seems to be feasible and, if confirmed, would provide a new extraction and acceleration mechanism for electrons, alternative to traditional radio-frequency-based or laser-wake-field ones.

  18. The slingshot effect: a possible new laser-driven high energy acceleration mechanism for electrons

    E-Print Network [OSTI]

    Gaetano Fiore; Renato Fedele; Umberto de Angelis

    2014-11-14

    We show that under appropriate conditions the impact of a very short and intense laser pulse onto a plasma causes the expulsion of surface electrons with high energy in the direction opposite to the one of propagation of the pulse. This is due to the combined effects of the ponderomotive force and the huge longitudinal field arising from charge separation ("slingshot effect"). The effect should also be present with other states of matter, provided the pulse is sufficiently intense to locally cause complete ionization. An experimental test seems to be feasible and, if confirmed, would provide a new extraction and acceleration mechanism for electrons, alternative to traditional radio-frequency-based or Laser-Wake-Field ones.

  19. Backscattering of an Intense Laser Beam by an Electron Fei He, Y.Y. Lau, Donald P. Umstadter, and Richard Kowalczyk

    E-Print Network [OSTI]

    Umstadter, Donald

    but is independent of the electron energy, that a high power laser does not necessarily produce high power radiation for this scattering problem from a low to an ultrahigh power laser, and from a low to an ultrahigh energy electron

  20. Development of high strength state laser materials

    SciTech Connect (OSTI)

    Marion, J.E.

    1986-08-15

    The threat of laser material fracture limits the average power of many laser to modest levels. Rupture occurs when the tensile surface stress, which results from the temperature gradient within the component, exceeds its strength. To increase the power output potential we have focussed on methods to strengthen the amplifier slabs. Two basic approaches are used; the subsurface damage from machining, and inducing a compressive stress at the slab surface. We report results on several strengthened systems including GSGG, GGG and YAG crystalline hosts, and LHG-5 phosphate glass (Hoya Glass Corp.).

  1. An optical parametric chirped-pulse amplifier for seeding high repetition rate free-electron lasers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Höppner, H.; Hage, A.; Tanikawa, T.; Schulz, M.; Riedel, R.; Teubner, U.; Prandolini, M. J.; Faatz, B.; Tavella, F.

    2015-05-15

    High repetition rate free-electron lasers (FEL), producing highly intense extreme ultraviolet and x-ray pulses, require new high power tunable femtosecond lasers for FEL seeding and FEL pump-probe experiments. A tunable, 112 W (burst mode) optical parametric chirped-pulse amplifier (OPCPA) is demonstrated with center frequencies ranging from 720–900 nm, pulse energies up to 1.12 mJ and a pulse duration of 30 fs at a repetition rate of 100 kHz. Since the power scalability of this OPCPA is limited by the OPCPA-pump amplifier, we also demonstrate a 6.7–13.7 kW (burst mode) thin-disk OPCPA-pump amplifier, increasing the possible OPCPA output power to manymore »hundreds of watts. Furthermore, third and fourth harmonic generation experiments are performed and the results are used to simulate a seeded FEL with high-gain harmonic generation.« less

  2. Observable effects caused by vacuum pair creation in the field of high-power optical lasers

    E-Print Network [OSTI]

    David B. Blaschke; Andrey V. Filatov; Irina A. Egorova; Alexander V. Prozorkevich; Stanislav A. Smolyansky

    2008-11-29

    We consider the possibility of an experimental proof of vacuum e+e- pair creation in the focus of two counter-propagating optical laser beams with an intensity of the order of 10^20 - 10^22 W/cm^2. Our approach is based on the collisionless kinetic equation for the distribution function of the e+e- pairs with the source term for particle production. As a possible experimental signal of vacuum pair production we consider the refraction of a high-frequency probe laser beam by the produced e+e- plasma to be observed by an interference filter. The generation of higher harmonics of the laser frequency in the self-consistent electric field is also investigated.

  3. Generation of high-energy electron-positron beams in the collision of a laser-accelerated electron beam and a multi-petawatt laser

    E-Print Network [OSTI]

    Lobet, Mathieu; d'Humičres, Emmanuel; Gremillet, Laurent

    2015-01-01

    Generation of antimatter via the multiphoton Breit-Wheeler process in an all-optical scheme will be made possible on forthcoming high-power laser facilities through the collision of wakefield-accelerated GeV electrons with a counter-propagating laser pulse with $10^{22}$-$10^{23}$ $\\mathrm{Wcm}^{-2}$ peak intensity. By means of integrated 3D particle-in-cell simulations, we show that the production of positron beams with 0.1-1 nC total charge, 100-400 MeV mean energy and 0.01-0.1 rad divergence is within the reach of soon-to-be-available laser systems. The variations of the positron beam's properties with respect to the laser parameters are also examined.

  4. Effective post-acceleration of ion bunches in foils irradiated by ultra-intense laser pulses

    SciTech Connect (OSTI)

    Andreev, A. A. [Max Born Institute, Max Born Str. 2a, D-12489 Berlin (Germany); Saint Petersburg State University, University Emb. 7-9, 199034 Saint Petersburg (Russian Federation); ELI-ALPS, Dugonics ter. 13 H-6720 Szeged (Hungary); Nickles, P. V. [Max Born Institute, Max Born Str. 2a, D-12489 Berlin (Germany); Center of Relativistic Laser Science, Institute for Basic Science, Gwangju 500-712 (Korea, Republic of); Platonov, K. Yu [Saint Petersburg State Technical University, Politekhnicheskaja 29, 195251 Saint Petersburg (Russian Federation)

    2014-08-15

    Two-step laser acceleration of protons with two foils and two laser pulses is modelled and optimized. It is shown that a nearly mono-energetic distribution of proton bunches can be realized by a suitable parameter choice. Two-step acceleration schemes make it possible to obtain both higher efficiency and energy as compared to the acceleration with only one laser pulse of an energy equal to the sum of the energy of the two pulses. With the aid of our analytical model, the optimal distance between the two targets, the delay between the two laser pulses, and the parameters of the laser pulses are determined. Estimates and results of the modelling are proven with 2D PIC simulations of the acceleration of proton bunches moving through the second target.

  5. Rider Energy Expenditure during High Intensity Horse Activity 

    E-Print Network [OSTI]

    O'Reilly, Colleen L

    2015-04-29

    (DDR) to determine if playing DDR for 30 min a day could meet minimum exercise requirements. Experienced DDR players as well as inexperienced DDR players were observed to determine if they could meet energy expenditure requirements. This study..., in contradiction with the Nintendo Wii study found that experienced DDR players exhibited exercise of a moderate intensity with mean HR of 161.2 beats per min (bpm) and mean VO2 of 25.2mL·kg -1·min-1 and expended more than 150 kcal in the 30 min exercise which...

  6. ISSUANCE 2015-12-02: Energy Conservation Program: Energy Conservation Standards for High-Intensity Discharge Lamps, Final Determination

    Office of Energy Efficiency and Renewable Energy (EERE)

    Energy Conservation Program: Energy Conservation Standards for High-Intensity Discharge Lamps, Final Determination

  7. High voltage switch triggered by a laser-photocathode subsystem

    DOE Patents [OSTI]

    Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

    2013-01-08

    A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

  8. Measurement of magnetic field produced by the interaction of ultra-short, ultra-intense fs laser pulse with matter

    SciTech Connect (OSTI)

    Zamponi, F.; Luebcke, A.; Uschmann, I.; Foerster, E.; Sauerbrey, R. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz, 1 07743 Jena (Germany); Kroupp, E.; Stambulchik, E.; Maron, Y. [Weizmann Institute of Science Rehovot 76100 (Israel); Fisher, D. [Soreq, NRC, Yavne 81800 (Israel)

    2006-04-07

    We report on the preliminary results of a first experiment where the Zeeman effect in the X-ray range was exploited to monitor the quasi static magnetic field, created by the interaction of an ultra-short (80 fs) ultra-intense fs laser pulse with solid matter.The involved laser intensities ranged between 1018 and 5{center_dot}1019 W/cm2. The target was a 25 {mu}m thick Ti foil. We monitored the X-ray emissions of the K{alpha}1 and K{alpha}2 lines by means of a spectrometer with 0.3 eV energy resolution and 20 {mu}m spatial resolution. The spectrometer was composed by a toroidally bent GaAs crystal and a Si plane crystal in dispersionless setup at 45 deg., working as polarizer, to distinguish contribution to the line broadening coming from other mechanisms.We observe an increasing broadening of the linewidth in dependence of the intensity but no differences between polarized and non-polarized spectra, probably because of a too low spatial resolution. A linewidth increase was measured to be 30%. We are working to determine the role of mechanisms other than the Zeeman effect in the measurements. Possible mechanisms causing line broadening, i.e. Stark effect, satellite lines, are discussed.If the Zeeman effect was the main cause for the measured line broadening, a magnetic field of 5000 tesla would be expected.

  9. Lifetime Analysis at High Intensity Colliders Applied to the LHC

    E-Print Network [OSTI]

    Salvachua, B; Bruce, R; Burkart, F; Redaelli, S; Valentino, G; Wollmann, D

    2013-01-01

    The beam lifetime is one of the main parameters to define the performance of a collider. In a super-conducting machine like the LHC, the lifetime determines the intensity reach for a given collimation cleaning. The beam lifetime can be calculated from the direct measurement of beam current. However, due to the noise in the beam current signal only an average lifetime over several seconds can be calculated. We propose here an alternative method, which uses the signal of the beam loss monitors in the vicinity of the primary collimators to get the instantaneous beam lifetime at the collimators. In this paper we compare the lifetime from the two methods and investigate the minimum lifetime over the LHC cycle for all the physics fills in 2011 and 2012. These data provide a reference for estimates of performance reach from collimator cleaning.

  10. On stochastic heating of electrons by intense laser radiation in the presence of electrostatic potential well

    SciTech Connect (OSTI)

    Krasheninnikov, S. I.

    2014-10-15

    A simple model developed by Paradkar et al. [Phys. Plasmas 19, 060703 (2012)] for the study of synergistic effects of electrostatic potential well and laser radiation is extended for the case where electric field of the well is accelerating electrons moving in the direction of the laser field propagation. It was found that in these cases, the rate of stochastic heating of energetic electrons remains virtually the same as in Paradkar et al. [Phys. Plasmas 19, 060703 (2012)], where electric field in electrostatic potential was slowing down electrons moving in the direction of the laser field propagation. However, the heating of electrons with relatively low energy can be sensitive to the orientation of the electrostatic potential well with respect to the direction of the laser radiation propagation.

  11. High energy KrCl electric discharge laser

    DOE Patents [OSTI]

    Sze, Robert C. (Santa Fe, NM); Scott, Peter B. (Los Alamos, NM)

    1981-01-01

    A high energy KrCl laser for producing coherent radiation at 222 nm. Output energies on the order of 100 mJ per pulse are produced utilizing a discharge excitation source to minimize formation of molecular ions, thereby minimizing absorption of laser radiation by the active medium. Additionally, HCl is used as a halogen donor which undergoes a harpooning reaction with metastable Kr.sub.M * to form KrCl.

  12. Non-intrusive beam power monitor for high power pulsed or continuous wave lasers

    DOE Patents [OSTI]

    Hawsey, Robert A. (Oak Ridge, TN); Scudiere, Matthew B. (Oak Ridge, TN)

    1993-01-01

    A system and method for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor.

  13. Ionization of oriented carbonyl-sulfide molecules by intense circularly polarized laser pulses

    E-Print Network [OSTI]

    Dimitrovski, Darko; Madsen, Lars Bojer; Filsinger, Frank; Meijer, Gerard; Küpper, Jochen; Holmegaard, Lotte; Kalhųj, Line; Nielsen, Jens H; Stapelfeldt, Henrik

    2010-01-01

    We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl-sulphide molecules by circularly-polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation.

  14. Driving laser pulse evolution in a hollow channel laser wakefield accelerator

    E-Print Network [OSTI]

    Wurtele, Jonathan

    Driving laser pulse evolution in a hollow channel laser wakefield accelerator P. Volfbeyn, P. B of the coupling between a high-intensity laser pulse and a plasma wake is presented, in the context of laser wakefield acceleration in a hollow channel. Laser wavelength reddening and pulse length shortening

  15. Development of a frequency doubled high powered laser diode end-pumped Nd:YVO?/LBO laser 

    E-Print Network [OSTI]

    Barr, Aaron Maxwell

    2003-01-01

    The development of a high power solid state laser poses a serious non-trivial task. Several different elements combine to form this complex quantum device. Each of the elements of the laser receives sufficient description herein. The pump source...

  16. Collapse BoseEinstein condensate induced by fluctuations laser intensity Laboratoire Statistique Probabilits, Universit, Paul Sabatier, 118 Route Narbonne, 31062 Toulouse Cedex

    E-Print Network [OSTI]

    Garnier, Josselin

    Collapse Bose­Einstein condensate induced by fluctuations laser intensity Garnier* Laboratoire­Einstein condensate trapped a system beams analyzed presence small fluctuations intensity. shown that condensate. collapse shows rapid strong shrinking the condensate some critical number of atoms, and accompanied

  17. Laser assisted high entropy alloy coating on aluminum: Microstructural evolution

    SciTech Connect (OSTI)

    Katakam, Shravana; Joshi, Sameehan S.; Mridha, Sanghita; Mukherjee, Sundeep; Dahotre, Narendra B.

    2014-09-14

    High entropy alloy (Al-Fe-Co-Cr-Ni) coatings were synthesized using laser surface engineering on aluminum substrate. Electron diffraction analysis confirmed the formation of solid solution of body centered cubic high entropy alloy phase along with phases with long range periodic structures within the coating. Evolution of such type of microstructure was a result of kinetics associated with laser process, which generates higher temperatures and rapid cooling resulting in retention of high entropy alloy phase followed by reheating and/or annealing in subsequent passes of the laser track giving rise to partial decomposition. The partial decomposition resulted in formation of precipitates having layered morphology with a mixture of high entropy alloy rich phases, compounds, and long range ordered phases.

  18. Dichroic beamsplitter for high energy laser diagnostics

    DOE Patents [OSTI]

    LaFortune, Kai N (Livermore, CA); Hurd, Randall (Tracy, CA); Fochs, Scott N (Livermore, CA); Rotter, Mark D (San Ramon, CA); Hackel, Lloyd (Livermore, CA)

    2011-08-30

    Wavefront control techniques are provided for the alignment and performance optimization of optical devices. A Shack-Hartmann wavefront sensor can be used to measure the wavefront distortion and a control system generates feedback error signal to optics inside the device to correct the wavefront. The system can be calibrated with a low-average-power probe laser. An optical element is provided to couple the optical device to a diagnostic/control package in a way that optimizes both the output power of the optical device and the coupling of the probe light into the diagnostics.

  19. Method for generating high-energy and high repetition rate laser pulses from CW amplifiers

    DOE Patents [OSTI]

    Zhang, Shukui

    2013-06-18

    A method for obtaining high-energy, high repetition rate laser pulses simultaneously using continuous wave (CW) amplifiers is described. The method provides for generating micro-joule level energy in pico-second laser pulses at Mega-hertz repetition rates.

  20. Generation of high power, high repetition-rate pulses using erbium-doped fiber ring laser 

    E-Print Network [OSTI]

    Hinson, Brett Darren

    1998-01-01

    peak power. The linear cavity laser produced pulses with repetition rates as high as 128 MHz and a peak power of 6 mW. The ring cavity laser produced pulses with repetition rates as high as 1 GHz and a peak power of 36 mW....

  1. Physical phenomena induced by passage of intense electromagnetic pulses (including CO/sub 2/ lasers) through the atmosphere

    SciTech Connect (OSTI)

    Yee, J.H.; Mayhall, D.J.; Alvarez, R.

    1985-10-23

    The electron fluid equations are combined with Maxwell's equations to investigate the physical phenomena that occurs when short, intense electromagnetic pulses (including the CO/sub 2/ laser pulse) interact with the atmosphere. The phenomena of ''tailed erosion'' occurs when the pulse intensity exceeds the air-breakdown threshold. In some cases, the erosion of the pulse occurs first in the middle of the pulse and then occurs in the tail of the pulse. In addition, we discovered that the amount of the energy that a pulse carries through the atmosphere is independent of whether it is propagating vertically upward from the Earth's surface or vertically downward toward the Earth's surface, provided the distance the pulse travels is the same for both directions of the propagation. 20 refs., 9 figs.

  2. Ti-Sapphire Tunable Laser. Verdi G-Series Family High-Power

    E-Print Network [OSTI]

    Wolberg, George

    -Sapphire Tunable Laser. Verdi G-Series Family High-Power Optically Pumped supply ­ to enable a laser platform that is easily scalable in power Semiconductor Laser ( OPSL) The Verdi G-Series is a revolutionary

  3. Laboratory Astrophysics Using High Intensity Particle and Photon...

    Office of Scientific and Technical Information (OSTI)

    We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory...

  4. Hollow-waveguide delivery systems for high-power, industrial CO2 lasers

    E-Print Network [OSTI]

    Hollow-waveguide delivery systems for high-power, industrial CO2 lasers Ricky K. Nubling and James to deliver CO2 laser power for industrial laser applications. The transmission, bending loss, and output, beam delivery, industrial lasers, power delivery, CO2 lasers. r 1996 Optical Society of America 1

  5. Improved Heat Transfer and Performance of High Intensity Combustion Systems for Reformer Furnace Applications 

    E-Print Network [OSTI]

    Williams, F. D. M.; Kondratas, H. M.

    1983-01-01

    Developments over the past fifteen years have evolved new short flame, high intensity (1,000,000 BTU/HR/ft3 ) combustion systems for industrial uses. Such systems produce a more uniform and higher heat flux than conventional low intensity systems...

  6. Trapping and Destruction of Long-Range High-Intensity Optical Filaments by Molecular Quantum Wakes in Air

    E-Print Network [OSTI]

    Milchberg, Howard

    in Air S. Varma, Y.-H. Chen, and H. M. Milchberg Institute for Research in Electronics and Applied in atmospheric air on the long-range filamentary propagation of intense femtosecond laser pulses. In a pump following a pump pulse filamenting in air has a dramatic effect on the propagation of an intense probe pulse

  7. Self-compression of intense short laser pulses in relativistic magnetized plasma

    SciTech Connect (OSTI)

    Olumi, M.; Maraghechi, B.

    2014-11-15

    The compression of a relativistic Gaussian laser pulse in a magnetized plasma is investigated. By considering relativistic nonlinearity and using non-linear Schrödinger equation with paraxial approximation, a second-order differential equation is obtained for the pulse width parameter (in time) to demonstrate the longitudinal pulse compression. The compression of laser pulse in a magnetized plasma can be observed by the numerical solution of the equation for the pulse width parameter. The effects of magnetic field and chirping are investigated. It is shown that in the presence of magnetic field and negative initial chirp, compression of pulse is significantly enhanced.

  8. Simulation of High-Intensity Mercury Jet Targets

    E-Print Network [OSTI]

    McDonald, Kirk

    of high speed jet cavitation and breakup FronTier MHD, a 3D code with explicitly tracked interfaces for cavitation Realistic equation of states Simulation studies focus on Distortion of mercury jets entering Smoothed Particle Hydrodynamics (SPH) Code · A new code for free surface / multiphase MHD flows is being

  9. MATERIAL STUDIES FOR PULSED HIGH-INTENSITY PROTON BEAM TARGETS

    E-Print Network [OSTI]

    McDonald, Kirk

    as high-Z target to be evaluated for effects of irradiation on CTE, fracture toughness and ductility loss or strength) degrade with radiation is unknown. Titanium Ti-6Al-4V alloy The evaluation of the fracture toughness changes due to irradiation is of interest regarding this alloy that combines good tensile strength

  10. High-intensity, high-brightness polarized and unpolarized beam production in charge-exchange collisions

    SciTech Connect (OSTI)

    Zelenski, A.; Ritter, J.; Zubets, V.; Steski, D.; Atoian, G.; Davydenko, V.; Ivanov, A.; Kolmogorov, A.

    2011-03-28

    Basic limitations on the high-intensity H{sup -} ion beam production were experimentally studied in charge-exchange collisions of the neutral atomic hydrogen beam in the Na-vapour jet ionizer cell. These studies are the part of the polarized source upgrade (to 10 mA peak current and 85% polarization) project for RHIC. In the source the atomic hydrogen beam of a 5-10 keV energy and total (equivalent) current up to 5 A is produced by neutralization of proton beam in pulsed hydrogen gas target. Formation of the proton beam (from the surface of the plasma emitter with a low transverse ion temperature {approx}0.2 eV) is produced by four-electrode spherical multi-aperture ion-optical system with geometrical focusing. The hydrogen atomic beam intensity up to 1.0 A/cm{sup 2} (equivalent) was obtained in the Na-jet ionizer aperture of a 2.0 cm diameter. At the first stage of the experiment H-beam with 36 mA current, 5 keV energy and {approx}1.0 cm {center_dot} mrad normalized emittance was obtained using the flat grids and magnetic focusing.

  11. High Rate Laser Pitting Technique for Solar Cell Texturing

    SciTech Connect (OSTI)

    Hans J. Herfurth; Henrikki Pantsar

    2013-01-10

    High rate laser pitting technique for solar cell texturing Efficiency of crystalline silicon solar cells can be improved by creating a texture on the surface to increase optical absorption. Different techniques have been developed for texturing, with the current state-of-the-art (SOA) being wet chemical etching. The process has poor optical performance, produces surfaces that are difficult to passivate or contact and is relatively expensive due to the use of hazardous chemicals. This project shall develop an alternative process for texturing mc-Si using laser micromachining. It will have the following features compared to the current SOA texturing process: -Superior optical surfaces for reduced front-surface reflection and enhanced optical absorption in thin mc-Si substrates -Improved surface passivation -More easily integrated into advanced back-contact cell concepts -Reduced use of hazardous chemicals and waste treatment -Similar or lower cost The process is based on laser pitting. The objective is to develop and demonstrate a high rate laser pitting process which will exceed the rate of former laser texturing processes by a factor of ten. The laser and scanning technologies will be demonstrated on a laboratory scale, but will use inherently technologies that can easily be scaled to production rates. The drastic increase in process velocity is required for the process to be implemented as an in-line process in PV manufacturing. The project includes laser process development, development of advanced optical systems for beam manipulation and cell reflectivity and efficiency testing. An improvement of over 0.5% absolute in efficiency is anticipated after laser-based texturing. The surface textures will be characterized optically, and solar cells will be fabricated with the new laser texturing to ensure that the new process is compatible with high-efficiency cell processing. The result will be demonstration of a prototype process that is suitable for scale-up to a production tool and process. The developed technique will have an reducing impact on product pricing. As efficiency has a substantial impact on the economics of solar cell production due to the high material cost content; in essence, improved efficiency through cost-effective texturing reduces the material cost component since the product is priced in terms of $/W. The project is a collaboration between Fraunhofer USA, Inc. and a c-Si PV manufacturer.

  12. High-Intensity Plasma Glass Melter Final Technical Report

    SciTech Connect (OSTI)

    Gonterman, J. Ronald; Weinstein, Michael A.

    2006-10-27

    The purpose of this project was to demonstrate the energy efficiency and reduced emissions that can be obtained with a dual torch DC plasma transferred arc-melting system. Plasmelt Glass Technologies, LLC was formed to solicit and execute the project, which utilize a full-scale test melter system. The system is similar to the one that was originally constructed by Johns Manville, but Plasmelt has added significant improvements to the torch design and melter system that has extended the original JM short torch lives. The original JM design has been shown to achieve melt rates 5 to 10 times faster than conventional gas or electric melting, with improved energy efficiency and reduced emissions. This project began on 7/28/2003 and ended 7/27/06. A laboratory scale melter was designed, constructed, and operated to conduct multiple experimental melting trials on various glass compositions. Glass quality was assessed. Although the melter design is generic and equally applicable to all sectors within the glass industry, the development of this melter has focused primarily on fiberglass with additional exploratory melting trials of frits, specialty, and minerals-melting applications. Throughput, energy efficiency, and glass quality have been shown to be heavily dependent on the selected glass composition. During this project, Plasmelt completed the proof-of-concept work in our Boulder, CO Lab to show the technical feasibility of this transferred-arc plasma melter. Late in the project, the work was focused on developing the processes and evaluating the economic viability of plasma melting aimed at the specific glasses of interest to specific client companies. Post project work is on going with client companies to address broader non-glass materials such as refractories and industrial minerals. Exploratory melting trials have been conducted on several glasses of commercial interest including: C-glass, E-glass, S-Glass, AR-Glass, B-glass, Lighting Glass, NE-Glass, and various frits. Exploratory melts of non-glassy materials, such as wollastonite, zirconium silicate, and alumino-silicate melts were successfully done indicating that plasma melting has potential application beyond glass. Experimental results were generated that show the high quality of plasma-melted fiberglass compositions, such as E-glass, can result in good fiberizing performance. Fiberizing performance and tensile strength data were achieved during the project to support this conclusion. High seed counts are a feature of the current lab scale melter and must be dealt with via other means, since fining work was outside the scope of this project.

  13. High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

    DOE Patents [OSTI]

    Freitas, Barry L. (Livermore, CA)

    1998-01-01

    An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver>4kW/cm2 of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources.

  14. Ionization of oriented carbonyl sulfide molecules by intense circularly polarized laser pulses

    SciTech Connect (OSTI)

    Dimitrovski, Darko; Abu-samha, Mahmoud; Madsen, Lars Bojer; Filsinger, Frank; Meijer, Gerard; Kuepper, Jochen [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); Holmegaard, Lotte; Kalhoej, Line [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Nielsen, Jens H. [Department of Physics, Aarhus University, DK-8000 Aarhus C (Denmark); Stapelfeldt, Henrik [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark)

    2011-02-15

    We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl sulfide molecules by circularly polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation. The focus of the present article is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons. In the following article [Phys. Rev. A 83, 023406 (2011)] the focus is to understand strong-field ionization from three-dimensionally-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals.

  15. Recent advances in phosphate laser glasses for high power applications

    SciTech Connect (OSTI)

    Campbell, J.H.

    1996-05-14

    Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bulk glass absorption have been carefully measured and can be accurately predicted. Improvements in processing have lead to high damage threshold (e.g. Pt inclusion free) and high thermal shock resistant glasses with improved edge claddings. High optical quality pieces up to 79 x 45 x 4cm{sup 3} have been made and methods for continuous melting laser glass are under development.

  16. Self-focusing and stimulated Brillouin back-scattering of a long intense laser pulse in a finite temperature relativistic plasma

    SciTech Connect (OSTI)

    Niknam, A. R.; Barzegar, S.; Hashemzadeh, M.

    2013-12-15

    The nonlinear dynamics of electromagnetic waves propagating through a plasma considering the effects of relativistic mass and ponderomotive nonlinearities is investigated. The modified electron density distribution, the dispersion relation, and the spatial profiles of electromagnetic wave amplitude in the plasma are obtained. It is shown that the cut-off frequency decreases, and there is an intensity range in which the ponderomotive self-focusing takes place. In the upper limit of this range, the laser beam is defocused due to the relativistic ponderomotive force. In addition, the stability of electromagnetic waves to stimulated Brillouin scattering is studied, and the backscattered wave resulting from decay of high power electromagnetic beam is resolved in relativistic regime. The study of effects of electron density and temperature on the growth rate of backscattered wave has been shown that by increasing these effects, the growth rate of instability increases.

  17. Light dark matter candidates in intense laser pulses I: paraphotons and fermionic minicharged particles

    E-Print Network [OSTI]

    Selym Villalba-Chįvez; Carsten Müller

    2014-12-15

    Polarimetric experiments driven by the strong field of a circularly polarized laser wave can become a powerful tool to limit the parameter space of not yet detected hidden-photons and minicharged particles associated with extra U(1) gauge symmetries. We show how the absorption and dispersion of probe electromagnetic waves in the vacuum polarized by such a background are modified due to the coupling between the visible U(1)-gauge sector and these hypothetical degrees of freedom. The results of this analysis reveal that the regime close to the two-photon reaction threshold can be a sensititive probe of these hidden particles. Parameters of modern laser systems are used to estimate the constraints on the corresponding coupling constants in regions where experiments driven by dipole magnets are less constricted. The role played by a paraphoton field is analyzed via a comparison with a model in which the existence of minicharges is assumed only. For both scenarios is found that the most stringent exclusion limit occurs at the lowest threshold mass; this one being determined by a certain combination of the field frequencies and dictated by energy momentum balance of the photo-production of a pair of minicharged particles. The dependencies of the observables on the laser attributes as well as on the unknown particle parameters are also analyzed.

  18. Free Electron Lasers Seeded by ir Laser Driven High-order Harmonic Generation

    SciTech Connect (OSTI)

    Wu, Juhao; Bolton, Paul R.; /SLAC; Murphy, James B.; /BNL, NSLS; Zhong, Xinming; /Beijing Normal U.

    2007-03-12

    Coherent x-ray production by a seeded free electron laser (FEL) is important for next generation synchrotron light sources. We examine the feasibility and features of FEL emission seeded by a high-order harmonic of an infrared laser (HHG). In addition to the intrinsic FEL chirp, the longitudinal profile and spectral bandwidth of the HHG seed are modified significantly by the FEL interaction well before saturation. This smears out the original attosecond pulselet structure. We introduce criteria for this smearing effect on the pulselet and the stretching effect on the entire pulse. We discuss the noise issue in such a seeded FEL.

  19. On the origin of super-hot electrons from intense laser interactions with solid targets having moderate scale length preformed plasmas

    SciTech Connect (OSTI)

    Krygier, A. G.; Schumacher, D. W.; Freeman, R. R.

    2014-02-15

    We use particle-in-cell modeling to identify the acceleration mechanism responsible for the observed generation of super-hot electrons in ultra-intense laser-plasma interactions with solid targets with pre-formed plasma. We identify several features of direct laser acceleration that drive the generation of super-hot electrons. We find that, in this regime, electrons that become super-hot are primarily injected by a looping mechanism that we call loop-injected direct acceleration.

  20. Relative intensity noise and frequency noise of a compact Brillouin laser made

    E-Print Network [OSTI]

    Boyer, Edmond

    made of 4.9 m long bulk As2Se3 (AsSe) chalcogenide fiber, which has a Brillouin gain coefficient g]. The purpose of this Letter is twofold: first to demonstrate the possibility of making compact BFLs made of AsSe performances in terms of intensity and frequency noise of a BFL made of chalco- genide MOF. The AsSe MOF [inset

  1. Method and system for modulation of gain suppression in high average power laser systems

    DOE Patents [OSTI]

    Bayramian, Andrew James (Manteca, CA)

    2012-07-31

    A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

  2. Investigation of relativistic intensity laser generated hot electron dynamics via copper K{sub ?} imaging and proton acceleration

    SciTech Connect (OSTI)

    Willingale, L.; Thomas, A. G. R.; Maksimchuk, A; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109 (United States)] [Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109 (United States); Morace, A. [University of California-San Diego, La Jolla, California 92093 (United States) [University of California-San Diego, La Jolla, California 92093 (United States); Universitą di Milano-Biocca, Piazza della Scienza 3, 20126 Milano (Italy); Bartal, T.; Kim, J.; Beg, F. N. [University of California-San Diego, La Jolla, California 92093 (United States)] [University of California-San Diego, La Jolla, California 92093 (United States); Stephens, R. B.; Wei, M. S. [General Atomics, San Diego, California 92121 (United States)] [General Atomics, San Diego, California 92121 (United States)

    2013-12-15

    Simultaneous experimental measurements of copper K{sub ?} imaging and the maximum target normal sheath acceleration proton energies from the rear target surface are compared for various target thicknesses. For the T-cubed laser (?4 J, 400 fs) at an intensity of ?2 × 10{sup 19} W cm{sup ?2}, the hot electron divergence is determined to be ?{sub HWHM}?22{sup °} using a K{sub ?} imaging diagnostic. The maximum proton energies are measured to follow the expected reduction with increasing target thickness. Numerical modeling produces copper K{sub ?} trends for both signal level and electron beam divergence that are in good agreement with the experiment. A geometric model describing the electron beam divergence reproduces the maximum proton energy trends observed from the experiment and the fast electron density and the peak electric field observed in the numerical modeling.

  3. High-Energy, Pulsed-Laser Diagnostics for Real-Time Measurements...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    High-Energy, Pulsed-Laser Diagnostics for Real-Time Measurements of Reciprocating Engine PM Emissions High-Energy, Pulsed-Laser Diagnostics for Real-Time Measurements of...

  4. High average power magnetic modulator for copper lasers

    SciTech Connect (OSTI)

    Cook, E.G.; Ball, D.G.; Birx, D.L.; Branum, J.D.; Peluso, S.E.; Langford, M.D.; Speer, R.D.; Sullivan, J.R.; Woods, P.G.

    1991-06-14

    Magnetic compression circuits show the promise of long life for operation at high average powers and high repetition rates. When the Atomic Vapor Laser Isotope Separation (AVLIS) Program at Lawrence Livermore National Laboratory needed new modulators to drive their higher power copper lasers in the Laser Demonstration Facility (LDF), existing technology using thyratron switched capacitor inversion circuits did not meet the goal for long lifetimes at the required power levels. We have demonstrated that magnetic compression circuits can achieve this goal. Improving thyratron lifetime is achieved by increasing the thyratron conduction time, thereby reducing the effect of cathode depletion. This paper describes a three stage magnetic modulator designed to provide a 60 kV pulse to a copper laser at a 4. 5 kHz repetition rate. This modulator operates at 34 kW input power and has exhibited MTBF of {approx}1000 hours when using thyratrons and even longer MTBFs with a series of stack of SCRs for the main switch. Within this paper, the electrical and mechanical designs for the magnetic compression circuits are discussed as are the important performance parameters of lifetime and jitter. Ancillary circuits such as the charge circuit and reset circuit are shown. 8 refs., 5 figs., 1 tab.

  5. Theoretical study of quantum molecular reaction dynamics and of the effects of intense laser radiation on a diatomic molecule

    SciTech Connect (OSTI)

    Dardi, P.S.

    1984-11-01

    Within the very broad field of molecular dynamics, we have concentrated on two simple yet important systems. The systems are simple enough so that they are adequately described with a single Born-Oppenheimer potential energy surface and that the dynamics can be calculated accurately. They are important because they give insight into solving more complicated systems. First we discuss H + H/sub 2/ reactive scattering. We present an exact formalism for atom-diatom reactive scattering which avoids the problem of finding a coordinate system appropriate for both reactants and products. We present computational results for collinear H + H/sub 2/ reactive scattering which agree very well with previous calculations. We also present a coupled channel distorted wave Born approximation for atom-diatom reactive scattering which we show is a first order approximation to our exact formalism. We present coupled channel DWBA results for three dimensional H + H/sub 2/ reactive scattering. The second system is an isolated HF molecule in an intense laser field. Using classical trajectories and quantum dynamics, we look at energy absorbed and transition probabilities as a function of the laser pulse time and also averaged over the pulse time. Calculations are performed for both rotating and nonrotating HF. We examine one and two photon absorption about the fundamental frequency, multiphoton absorption, and overtone absorption. 127 references, 31 figures, 12 tables.

  6. Solidi cation of a high-Reynolds-number ow in laser percussion drilling

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    Solidi#12;cation of a high-Reynolds-number ow in laser percussion drilling W. R. Smith y and R. M laser percussion drilling. 1 Introduction Laser percussion drilling is used to machine gas turbine with conventional mechanical drills. The term percussion refers to the repeated operation of the laser in short

  7. High-Level Fusion of Depth and Intensity for Pedestrian Classification

    E-Print Network [OSTI]

    Gavrila, Dariu M.

    High-Level Fusion of Depth and Intensity for Pedestrian Classification Marcus Rohrbach1,3 , Markus. This paper presents a novel approach to pedestrian classi- fication which involves a high-level fusion pedestrians and non-pedestrians. We refrain from the construction of a joint feature space, but instead employ

  8. Laser acceleration of ion beams

    E-Print Network [OSTI]

    I. A. Egorova; A. V. Filatov; A. V. Prozorkevich; S. A. Smolyansky; D. B. Blaschke; M. Chubaryan

    2007-02-01

    We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.

  9. Lasers

    SciTech Connect (OSTI)

    1995-01-01

    The scope of our research in laser and related technologies has grown over the years and has attracted a broad user base for applications within DOE, DOD, and private industry. Within the next few years, we expect to begin constructing the National Ignition Facility, to make substantial progress in deploying AVLIS technology for uranium and gadolinium enrichment, and to develop new radar sensing techniques to detect underwater objects. Further, we expect to translate LLNL patent ideas in microlithography into useful industrial products and to successfully apply high-power, diode-based laser technology to industrial and government applications.

  10. Control system for high power laser drilling workover and completion unit

    DOE Patents [OSTI]

    Zediker, Mark S; Makki, Siamak; Faircloth, Brian O; DeWitt, Ronald A; Allen, Erik C; Underwood, Lance D

    2015-05-12

    A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

  11. High-power laser beam control by PTR Bragg gratings Igor Ciapurin(1)

    E-Print Network [OSTI]

    Glebov, Leon

    High-power laser beam control by PTR Bragg gratings Igor Ciapurin(1) , Vadim Smirnov(1,2) , George is a photo-thermo-refractive (PTR) glass, and used for high-power laser beam control. Exceptionally narrow combining (SBC) is considered as a promising way for high power laser systems design in numerous

  12. Isolated short attosecond pulse generated using a two-color laser and a high-order pulse

    SciTech Connect (OSTI)

    Du, Hongchuan; Hu, Bitao [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang, Huiqiao [Institute of Theoretical Physics, Lanzhou University, Lanzhou 730000 (China)

    2010-06-15

    An efficient method to generate an isolated short attosecond pulse is investigated theoretically. A broadband extreme ultraviolet supercontinuum harmonics can be generated when a model He{sup +} ion is exposed to the combination of an intense few-cycle laser pulse and a low-frequency field. By properly adding a 27th harmonics pulse to resonantly excite the He{sup +} ion, the intensity of the high-order harmonic generation (HHG) plateau is enhanced by 3-4 orders of magnitude. As a result, an isolated 24-as pulse with a bandwidth of 138 eV can be obtained directly from the supercontinuum around the cutoff of HHG.

  13. High power continuous-wave titanium:sapphire laser

    DOE Patents [OSTI]

    Erbert, G.V.; Bass, I.L.; Hackel, R.P.; Jenkins, S.L.; Kanz, V.K.; Paisner, J.A.

    1993-09-21

    A high-power continuous-wave laser resonator is provided, wherein first, second, third, fourth, fifth and sixth mirrors form a double-Z optical cavity. A first Ti:sapphire rod is disposed between the second and third mirrors and at the mid-point of the length of the optical cavity, and a second Ti:sapphire rod is disposed between the fourth and fifth mirrors at a quarter-length point in the optical cavity. Each Ti:sapphire rod is pumped by two counter-propagating pump beams from a pair of argon-ion lasers. For narrow band operation, a 3-plate birefringent filter and an etalon are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors are disposed between the first and second mirrors to form a triple-Z optical cavity. A third Ti:sapphire rod is disposed between the seventh and eighth mirrors at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers. 5 figures.

  14. High power continuous-wave titanium:sapphire laser

    DOE Patents [OSTI]

    Erbert, Gaylen V. (Livermore, CA); Bass, Isaac L. (Castro Valley, CA); Hackel, Richard P. (Livermore, CA); Jenkins, Sherman L. (Livermore, CA); Kanz, Vernon K. (Livermore, CA); Paisner, Jeffrey A. (Danville, CA)

    1993-01-01

    A high-power continuous-wave laser resonator (10) is provided, wherein first, second, third, fourth, fifth and sixth mirrors (11-16) form a double-Z optical cavity. A first Ti:Sapphire rod (17) is disposed between the second and third mirrors (12,13) and at the mid-point of the length of the optical cavity, and a second Ti:Sapphire rod (18) is disposed between the fourth and fifth mirrors (14,15) at a quarter-length point in the optical cavity. Each Ti:Sapphire rod (17,18) is pumped by two counter-propagating pump beams from a pair of argon-ion lasers (21-22, 23-24). For narrow band operation, a 3-plate birefringent filter (36) and an etalon (37) are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors (101, 192) are disposed between the first and second mirrors (11, 12) to form a triple-Z optical cavity. A third Ti:Sapphire rod (103) is disposed between the seventh and eighth mirrors (101, 102) at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers (104, 105).

  15. PHYSICAL REVIEW A 88, 043413 (2013) Nuclear-wave-packet quantum interference in the intense laser dissociation of the D2

    E-Print Network [OSTI]

    Moiseyev, Nimrod

    2013-01-01

    PHYSICAL REVIEW A 88, 043413 (2013) Nuclear-wave-packet quantum interference in the intense laser of Debrecen, H-4010 Debrecen, PO Box 12, Hungary ´Agnes Vib´ok* Department of Theoretical Physics, University of Physics, and Minerva Center of Nonlinear Physics in Complex Systems, Technion - Israel Institute

  16. An unprecedented blend of intense magnetic and X-ray laser pulses...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    planet to discover a surprising three-dimensional (3D) arrangement of a material's electrons that appears closely linked to a mysterious phenomenon known as high-temperature...

  17. Electron generation and transport in intense relativistic laser-plasma interactions relevant to fast ignition ICF

    E-Print Network [OSTI]

    Ma, Tammy Yee Wing

    2010-01-01

    1.1 Basics of Inertial Confinement Fusion with High Poweredguided fast-ignition inertial confinement fusion, Phys. Rev.Fast-Ignition Inertial Confinement Fusion,” Physical Review

  18. A highly efficient, compact Yb:KYW laser for mobile precision systems

    SciTech Connect (OSTI)

    Kuznetsov, S A; Pivtsov, V S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2014-05-30

    We have developed a promising scheme of a multimodediode-pumped ytterbium laser. The Yb:KYW laser in the cw regime demonstrates record-high differential (40%) and total optical (35%) efficiencies. Mode locking is realised, which allows the scheme to be used for the development of compact laser systems, such as mobile femtosecond precision synthesisers. The peculiarities of the laser operation and ways of further improving its efficiency are discussed. (lasers)

  19. Development of high gradient laser wakefield accelerators towards nuclear detection applications at LBNL

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    compact systems. Laser-driven, plasma wakefield accelerators (LWFAs) [2] in use at LBNL provide high than conventional linacs, and confirms the anticipated scaling of laser driven accelerators to GeDevelopment of high gradient laser wakefield accelerators towards nuclear detection applications

  20. PROPERTIES OF RELATIVELY-DILUTEPLASMAS IN PULSED-POWER SYSTEMS OBTAINED FROM HIGH-ACCURACY LASER

    E-Print Network [OSTI]

    PROPERTIES OF RELATIVELY-DILUTEPLASMAS IN PULSED-POWER SYSTEMS OBTAINED FROM HIGH-ACCURACY LASER plasmas under high-power pulses at the nanosecond time scale. The method is based on resonant laser application of laser-spectroscopy to investigate the electric fields and the properties of relatively dilute

  1. Narrowing of high power diode laser arrays using reflection feedback from an etalon

    E-Print Network [OSTI]

    Romalis, Mike

    Narrowing of high power diode laser arrays using reflection feedback from an etalon M. V. Romalisa for publication 27 June 2000 The spectrum of a high power multielement laser array is narrowed using reflection of the laser array is reduced by a factor of 2 with only 6% power loss. This reduction in FWHM is useful

  2. High power CW Tm:YLF laser with a holographic output Alex Dergachev, Peter F. Moulton

    E-Print Network [OSTI]

    Glebov, Leon

    High power CW Tm:YLF laser with a holographic output coupler Alex Dergachev, Peter F. Moulton Q with output power exceeding 30 W. 2003 Optical Society of America OCIS codes: (140.3580) Lasers, solid yet reported of a high power Tm-doped bulk laser operated with a bulk holographic Bragg grating

  3. A LASER-BASED MEASUREMENT DEVICE FOR HIGHLY RADIOACTIVE SPECIMENS

    SciTech Connect (OSTI)

    Strachan, Denis M.; Buchmiller, William C.; Park, Walter R.; Munley, John T.

    2004-01-05

    A laser-based measurement device was developed so that the dimensions of highly radioactive specimens could be monitored over the span of several years. The device employs two laser curtain and diode detector pairs that are mounted orthogonally to each other. Each pair has its own controller, which is used to obtain 3500 simultaneous measurements of the height and diameter of the specimens. The precision of the measurements is less than 10 {micro}m over a period of more that two years. The device was also used to measure various parallelepipeds. It was possible to determine the dimensions of these parallelepipeds and the angle between the sides. Several improvements to the device are recommended.

  4. Superconductivity-induced phonon anomalies in high-Tc superconductors: A Raman intensity study

    E-Print Network [OSTI]

    Sipe,J. E.

    Superconductivity-induced phonon anomalies in high-Tc superconductors: A Raman intensity study O. V of a number of Raman-active phonons below the superconducting transition temperature in YBa2Cu3O7 x , Bi2Sr2Ca to obtain information about the superconducting state.4 Several years ago, Friedl et al.5 ob- served

  5. Target Material Irradiation Studies for High-Intensity Accelerator Beams , H. Ludewig1

    E-Print Network [OSTI]

    McDonald, Kirk

    Target Material Irradiation Studies for High-Intensity Accelerator Beams N. Simos1* , H. Kirk1 , H on the behavior of special materials and composites under irradiation conditions and their potential use irradiated target material. The ever greater deposited energy and induced thermo-mechanical loads combined

  6. Bright x-ray sources from laser irradiation of foams with high...

    Office of Scientific and Technical Information (OSTI)

    Bright x-ray sources from laser irradiation of foams with high concentration of Ti Citation Details In-Document Search Title: Bright x-ray sources from laser irradiation of foams...

  7. Pressure-driven, resistive magnetohydrodynamic interchange instabilities in laser-produced high-energy-density plasmas

    E-Print Network [OSTI]

    Li, Chikang

    Recent experiments using proton backlighting of laser-foil interactions provide unique opportunities for studying magnetized plasma instabilities in laser-produced high-energy-density plasmas. Time-gated proton radiograph ...

  8. Explosively pumped laser light

    DOE Patents [OSTI]

    Piltch, Martin S. (Los Alamos, NM); Michelotti, Roy A. (Los Alamos, NM)

    1991-01-01

    A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

  9. Electric characteristics of germanium Vertical Multijunction (VMJ) photovoltaic cells under high intensity illumination

    SciTech Connect (OSTI)

    Unishkov, V.A.

    1997-03-01

    This paper presents the results of the performance evaluation of Vertical Multijunction (VMJ) germanium (Ge) photovoltaic (PV) cells. Vertical Multijunction Germanium Photovoltaic cells offer several advantages for Thermophotovoltaic (TPV) applications such as high intensity light conversion, low series resistance, more efficient coupling to lower temperature sources, high output voltage, simplified heat rejection system as well as potentially simple fabrication technology and low cost photovoltaic converter device. {copyright} {ital 1997 American Institute of Physics.}

  10. Influence of irradiation with {gamma}-ray photons on the photoluminescence of Cd{sub 0.9}Zn{sub 0.1}Te crystals preliminarily subjected to the intense radiation of a neodymium laser

    SciTech Connect (OSTI)

    Glinchuk, K. D.; Medvid', A. P.; Mychko, A. M.; Naseka, Yu. M.; Prokhorovich, A. V.; Strilchuk, O. M.

    2013-04-15

    The effect of the preliminary treatment of Cd{sub 0.9}Zn{sub 0.1}Te crystals with high-power pulses of neodymium laser radiation (the power density is {<=}1.8 MW/cm{sup 2}, at a wavelength of 532 nm) on the low-temperature (5 K) photoluminescence induced by {gamma}-ray radiation (the dose was {Phi}{sub {gamma}} = 5 kGy) is studied. The luminescence bands are related to radiation-stimulated donor-acceptor pairs, which include shallow neutral donors and neutral cadmium vacancies stimulated by {gamma}-ray irradiation, the transition of free electrons to neutral cadmium vacancies formed by radiation, and the annihilation of excitons bound to the above vacancies. It is shown that, in the crystals preliminarily treated with laser radiation, the intensity of the {gamma}-ray-stimulated luminescence bands is significantly lower than in crystals not subjected to laser radiation. This fact is accounted for by a decrease in the concentration of cadmium vacancies generated by the {gamma}-ray radiation as a result of their annihilation during the course of their interaction with laser-stimulated defects, in particular, as a consequence of their recombination at laser-stimulated interstitial cadmium atoms.

  11. High power laser heating of low absorption materials

    SciTech Connect (OSTI)

    Olson, K.; Talghader, J.; Ogloza, A.; Thomas, J.

    2014-09-28

    A model is presented and confirmed experimentally that explains the anomalous behavior observed in continuous wave (CW) excitation of thermally isolated optics. Distributed Bragg Reflector (DBR) high reflective optical thin film coatings of HfO? and SiO?were prepared with a very low absorption, about 7 ppm, measured by photothermal common-path interferometry. When illuminated with a 17 kW CW laser for 30 s, the coatings survived peak irradiances of 13 MW/cm², on 500 ?m diameter spot cross sections. The temperature profile of the optical surfaces was measured using a calibrated thermal imaging camera for illuminated spot sizes ranging from 500 ?m to 5 mm; about the same peak temperatures were recorded regardless of spot size. This phenomenon is explained by solving the heat equation for an optic of finite dimensions and taking into account the non-idealities of the experiment. An analytical result is also derived showing the relationship between millisecond pulse to CW laser operation where (1) the heating is proportional to the laser irradiance (W/m²) for millisecond pulses, (2) the heating is proportional to the beam radius (W/m) for CW, and (3) the heating is proportional to W/m? tan?¹(?(t)/m) in the transition region between the two.

  12. Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

    SciTech Connect (OSTI)

    Dadfarnia, Mohsen; Nibur, Kevin A.; San Marchi, Christopher W.; Sofronis, Petros; Somerday, Brian P.; Foulk, James W., III; Hayden, Gary A.

    2010-07-01

    Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

  13. Method and apparatus for delivering high power laser energy over long distances

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-04-07

    Systems, devices and methods for the transmission and delivery of high power laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  14. Experimental astrophysics with high power lasers and Z pinches

    SciTech Connect (OSTI)

    Remington, B A; Drake, R P; Ryutov, D D

    2004-12-10

    With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

  15. Report of the Snowmass M6 Working Group on high intensity proton sources

    SciTech Connect (OSTI)

    Weiren Chou and J. Wei

    2002-08-20

    The U.S. high-energy physics program needs an intense proton source, a 1-4 MW Proton Driver (PD), by the end of this decade. This machine will serve as a stand-alone facility that will provide neutrino superbeams and other high intensity secondary beams such as kaons, muons, neutrons, and anti-protons (cf. E1 and E5 group reports) and also serve as the first stage of a neutrino factory (cf. M1 group report). It can also be a high brightness source for a VLHC. Based on present accelerator technology and project construction experience, it is both feasible and cost-effective to construct a 1-4 MW Proton Driver. Two recent PD design studies have been made, one at FNAL and the other at the BNL. Both designed PD's for 1 MW proton beams at a cost of about U.S. $200M (excluding contingency and overhead) and both designs were upgradeable to 4 MW. An international collaboration between FNAL, BNL and KEK on high intensity proton facilities is addressing a number of key design issues. The superconducting (sc) RF cavities, cryogenics, and RF controls developed for the SNS can be directly adopted to save R&D efforts, cost, and schedule. PD studies are also actively being pursued at Europe and Japan.

  16. REPORT OF THE SNOWMASS M6 WORKING GROUP ON HIGH INTENSITY PROTON SOURCES.

    SciTech Connect (OSTI)

    CHOU,W.; WEI,J.

    2001-08-14

    The M6 working group had more than 40 active participants (listed in Section 4). During the three weeks at Snowmass, there were about 50 presentations, covering a wide range of topics associated with high intensity proton sources. The talks are listed in Section 5. This group also had joint sessions with a number of other working groups, including E1 (Neutrino Factories and Muon Colliders), E5 (Fixed-Target Experiments), M1 (Muon Based Systems), T4 (Particle Sources), T5 (Beam dynamics), T7 (High Performance Computing) and T9 (Diagnostics). The M6 group performed a survey of the beam parameters of existing and proposed high intensity proton sources, in particular, of the proton drivers. The results are listed in Table 1. These parameters are compared with the requirements of high-energy physics users of secondary beams in Working Groups E1 and E5. According to the consensus reached in the E1 and E5 groups, the U.S. HEP program requires an intense proton source, a 1-4 MW Proton Driver, by the end of this decade.

  17. Early-time interface instabilities in high intensity aero-breakup of liquid drop

    E-Print Network [OSTI]

    Hu, X Y

    2014-01-01

    The early-time interface instabilities in high intensity (high Weber number and high Reynolds number) aero-breakup of a liquid drop are investigated by numerical simulations. A combined analysis based on simulation results and linear-instability theory show that both RT (Rayleigh-Taylor) and KH (Kelvin-Helmholtz) instabilities contributes the dominant disturbances originate from about the half way from the stagnation point to the equator. This is verified further with a specially modified simulation, which decreases the effect of KH instability while keeps other flow properties unchanged.

  18. Three-dimensional grain boundary spectroscopy in transparent high power ceramic laser

    E-Print Network [OSTI]

    Byer, Robert L.

    Three-dimensional grain boundary spectroscopy in transparent high power ceramic laser materials across grain boundaries (GBs) in Nd3+ :YAG laser ceramics. It is clearly shown that Nd3+ segregation point the way to further improvements in what is already an impressive class of ceramic laser materials

  19. High-precision CO2 isotopologue spectrometer with a difference-frequency-generation laser source

    E-Print Network [OSTI]

    High-precision CO2 isotopologue spectrometer with a difference-frequency-generation laser source A precision laser spectrometer for the detection of CO2 isotopes is reported. The spectrometer measures the fundamental absorption signatures of 13 C and 12 C isotopes in CO2 at 4.32 m using a tunable mid-IR laser

  20. Title of Dissertation: HIGH POWER NONLINEAR PROPAGATION OF LASER PULSES IN TENUOUS GASES

    E-Print Network [OSTI]

    Anlage, Steven

    ABSTRACT Title of Dissertation: HIGH POWER NONLINEAR PROPAGATION OF LASER PULSES IN TENUOUS GASES gas focusing, is observed. For even higher powers, the laser pulse is partially trapped by the plasma laser pulses in tenuous gases is studied. The dynamics of these pulses will be affected by nonlinear

  1. Invited Paper 505 In High-Power Laser Ablation V, Claude R. Phipps, Editor

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Invited Paper 505 In High-Power Laser Ablation V, Claude R. Phipps, Editor Proceedings of SPIE, Vol. 5448 (2004) Computer modeling of laser melting and spallation of metal targets Leonid V. Zhigilei in short pulse laser processing are investigated in a computational study performed with a hybrid atomistic

  2. Backcoupling of acoustic streaming on the temperature field inside high-intensity discharge lamps

    E-Print Network [OSTI]

    Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2015-01-01

    Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light intensity fluctuations and even lamp destruction are possible. The reason for the fluctuating discharge arc are acoustic resonances in this frequency range that are excited in the arc tube. The acoustic resonances in turn generate a fluid flow that is caused by the acoustic streaming effect. Here, we present a 3D multiphysics model to determine the influence of acoustic streaming on the temperature field in the vicinity of an acoustic eigenfrequency. In that case a transition from stable to instable behavior occurs. The model is able to predict when light flicker can be expected. The results are in very good accordance with accompanying experiments.

  3. Calculation of synchrotron radiation from high intensity electron beam at eRHIC

    SciTech Connect (OSTI)

    Jing Y.; Chubar, O.; Litvinenko, V.

    2012-05-20

    The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

  4. Numerical simulations of stripping effects in high-intensity hydrogen ion linacs

    SciTech Connect (OSTI)

    Carneiro, J.-P.; Mustapha, B.; Ostroumov, P.N.; /Argonne

    2008-12-01

    Numerical simulations of H{sup -} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H{sup -} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.

  5. Spatiotemporal study of the local thermodynamic equilibrium deviations in high-intensity discharge lamps

    SciTech Connect (OSTI)

    Helali, H.; Bchir, T.; Araoud, Z.; Charrada, K.

    2013-04-15

    The aim of this work is to study the local thermodynamic equilibrium (LTE) deviations in arc discharges plasma generated in high-intensity discharge lamps operating under an ac (50 Hz) power supply. To achieve this goal, we elaborate a two-temperature, two-dimensional, and time-depending model. We have found numerical results almost reproducing the experimental data, which allows us to validate this model. After validation, we have discussed different energy term effects on the LTE deviations.

  6. High harmonic generation from periodic potentials driven by few-cycle laser pulses

    E-Print Network [OSTI]

    Guan, Zhong; Bian, Xue-Bin

    2015-01-01

    We investigate the high harmonic generation (HHG) from solids by simulating the dynamics of a single active electron in periodic potentials. The corresponding time-dependent Schr\\"odinger equations (TDSE) are solved numerically by using B-spline basis sets in coordinate space. The energy band structure and wave vectors can be directly retrived from the eigenfunctions. The harmonic spectra obtained agree well with the results simulated by TDSE in $k$ space using Bloch states and show a two-plateau structure. Both of the cutoff energies of the two plateaus in the harmonic spectrum scale linearly with the field strength. We also study HHG driven by intense few-cycle laser pulses and find that the cutoff energy of the harmonic spectrum is as sensitive to the changes of the carrier envelope phase, as to HHG from gas samples, which suggests recollision pictures in HHG as found by recent experiments (Nature {\\bf 522}, 462 (2015)).

  7. Plasma wakefields driven by an incoherent combination of laser pulses: A path towards high-average power laser-plasma acceleratorsa)

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    -average power laser-plasma acceleratorsa) C. Benedetti,b) C. B. Schroeder, E. Esarey, and W. P. Leemans Lawrence enable a technologically simpler path to high-repetition rate, high-average power laserPlasma wakefields driven by an incoherent combination of laser pulses: A path towards high

  8. Nonlinear photoresponse of field effect transistors terahertz detectors at high irradiation intensities

    SciTech Connect (OSTI)

    But, D. B.; Drexler, C.; Ganichev, S. D.; Sakhno, M. V.; Sizov, F. F.; Dyakonova, N.; Drachenko, O.; Gutin, A.; Knap, W.

    2014-04-28

    Terahertz power dependence of the photoresponse of field effect transistors, operating at frequencies from 0.1 to 3 THz for incident radiation power density up to 100?kW/cm{sup 2} was studied for Si metal–oxide–semiconductor field-effect transistors and InGaAs high electron mobility transistors. The photoresponse increased linearly with increasing radiation intensity up to the kW/cm{sup 2} range. Nonlinearity followed by saturation of the photoresponse was observed for all investigated field effect transistors for intensities above several kW/cm{sup 2}. The observed photoresponse nonlinearity is explained by nonlinearity and saturation of the transistor channel current. A theoretical model of terahertz field effect transistor photoresponse at high intensity was developed. The model explains quantitative experimental data both in linear and nonlinear regions. Our results show that dynamic range of field effect transistors is very high and can extend over more than six orders of magnitudes of power densities (from ?0.5 mW/cm{sup 2} to ?5?kW/cm{sup 2})

  9. Method and system for advancement of a borehole using a high power laser

    DOE Patents [OSTI]

    Moxley, Joel F.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Zediker, Mark S.

    2014-09-09

    There is provided a system, apparatus and methods for the laser drilling of a borehole in the earth. There is further provided with in the systems a means for delivering high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates, a laser bottom hole assembly, and fluid directing techniques and assemblies for removing the displaced material from the borehole.

  10. Method and apparatus for delivering high power laser energy over long distances

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2013-08-20

    Systems, devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  11. Annual Scientific Report for DE-FG03-02NA00063 Coherent imaging of laser-plasma interactions using XUV high harmonic radiation

    SciTech Connect (OSTI)

    Prof. Henry C. Kapteyn

    2005-05-03

    In this project, we use coherent short-wavelength light generated using high-order harmonic generation as a probe of laser-plasma dynamics and phase transitions on femtosecond time-scales. The interaction of ultrashort laser pulses with materials and plasmas is relevant to stockpile stewardship, to understanding the equation of state of matter at high pressures and temperatures, and to plasma concepts such as the fast-ignitor ICF fusion concept and laser-based particle acceleration. Femtosecond laser technology makes it possible to use a small-scale setup to generate 20fs pulses with average power >10W at multiple kHz repetition rates, that can be focused to intensities in excess of 1017W/cm2. These lasers can be used either to rapidly heat materials to initiate phase transitions, or to create laser plasmas over a wide parameter space. These lasers can also be used to generate fully spatially coherent XUV beams with which to probe these materials and plasma systems. We are in process of implementing imaging studies of plasma hydrodynamics and warm, dense matter. The data will be compared with simulation codes of laser-plasma interactions, making it possible to refine and validate these codes.

  12. Performance and production requirements for the optical components in a high-average-power laser system

    SciTech Connect (OSTI)

    Chow, R.; Doss, F.W.; Taylor, J.R.; Wong, J.N.

    1999-07-02

    Optical components needed for high-average-power lasers, such as those developed for Atomic Vapor Laser Isotope Separation (AVLIS), require high levels of performance and reliability. Over the past two decades, optical component requirements for this purpose have been optimized and performance and reliability have been demonstrated. Many of the optical components that are exposed to the high power laser light affect the quality of the beam as it is transported through the system. The specifications for these optics are described including a few parameters not previously reported and some component manufacturing and testing experience. Key words: High-average-power laser, coating efficiency, absorption, optical components

  13. Generation of high-purity higher-order Laguerre-Gauss beams at high laser power

    E-Print Network [OSTI]

    L. Carbone; C. Bogan; P. Fulda; A. Freise; B. Willke

    2013-03-14

    We have investigated the generation of highly pure higher-order Laguerre-Gauss (LG) beams at high laser power of order 100W, the same regime that will be used by 2nd generation gravitational wave interferometers such as Advanced LIGO. We report on the generation of a helical type LG33 mode with a purity of order 97% at a power of 83W, the highest power ever reported in literature for a higher-order LG mode.

  14. Devices for high precision x-ray beam intensity monitoring on BSRF

    E-Print Network [OSTI]

    Hua-Peng, LI; Zhao, Yi-Dong; Zheng, Lei; Liu, Shu-Hu; Zhao, Xiao-Liang; Zhao, Ya-Shuai

    2016-01-01

    Synchrotron radiation with the characteristic of high brilliance, high level of polarization, high collimation, low emittance and wide tunability in energy has been used as a standard source in metrology(1, 2). For a decade, lots of calibration work have been done on 4B7A in Beijing Synchrotron Radiation Facility (BSRF) (3, 4). For the calibration process, a high-precision online monitor is indispensable. To control the uncertainty under 0.1%, we studied different sizes parallel ion chambers with rare-gas and used different collecting methods to monitor the x-ray intensity of the beamline. Two methods to collect the signal of the ion chambers: reading the current directly with electrometer or signal amplification to collect the counts were compared.

  15. High-field half-cycle terahertz radiation from relativistic laser interaction with thin solid targets

    SciTech Connect (OSTI)

    Ding, W. J.; Koh, W. S. [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore)] [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore); Sheng, Z. M. [Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2013-11-11

    It is found that half-cycle terahertz (THz) pulses with the peak field over 100 MV/cm can be produced in ultrashort intense laser interactions with thin solid targets. These THz pulses are shown to emit from both the front and rear sides of the solid target and are attributed to the coherent transition radiation by laser-produced ultrashort fast electron bunches. After the primary THz pulses, subsequent secondary half-cycle pulses are generated while some refluxing electrons cross the vacuum-target interfaces. Since such strong THz radiation is well synchronized with the driving lasers, it is particularly suitable for applications in various pump-probe experiments.

  16. A TWO-PHASE HEAT SPREADER FOR COOLING HIGH HEAT FLUX SOURCES Mitsuo Hashimoto, Hiroto Kasai, Yuichi Ishida, Hiroyuki Ryoson, a

    E-Print Network [OSTI]

    -power lasers, high-intensity light-emitting diodes (LEDs), and semiconductor power devices. The heat spreader

  17. Methods for enhancing the efficiency of creating a borehole using high power laser systems

    DOE Patents [OSTI]

    Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-06-24

    Methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena to enhance the formation of Boreholes. Methods for the laser operations to reduce the critical path for forming a borehole in the earth. These methods can deliver high power laser energy down a deep borehole, while maintaining the high power to perform operations in such boreholes deep within the earth.

  18. Gain media edge treatment to suppress amplified spontaneous emission in a high power laser

    DOE Patents [OSTI]

    Hackel, Lloyd A. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Fochs, Scott N. (Livermore, CA); Rotter, Mark D. (San Ramon, CA); Letts, Stephan A. (San Ramon, CA)

    2008-12-09

    A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

  19. Time-dependent density-functional theory for molecular processes in strong fields: Study of multiphoton processes and dynamical response of individual valence electrons of N2 in intense laser fields

    E-Print Network [OSTI]

    Chu, Xi; Chu, Shih-I

    2001-11-14

    We present a time-dependent density-functional theory (TDDFT) with proper asymptotic long-range potential for nonperturbative treatment of multiphoton processes of many-electron molecular systems in intense laser fields. ...

  20. Deformable Mirrors for High-Power Lasers Supriyo Sinha*a, Justin D. Mansell**b, and Robert L. Byer'

    E-Print Network [OSTI]

    Byer, Robert L.

    Deformable Mirrors for High-Power Lasers Supriyo Sinha*a, Justin D. Mansell**b, and Robert L. Byer with high power lasers. A reflectance of greater than 99.9% was measured and the mirror had a residual of average laser power (350W/cm2) was reduced from 88 nmto 31 nmrms. Keywords: deformable mirrors, lasers

  1. Comparison of hard x-ray production from various targets in air using a short pulse kHz laser with photon production from a high power multifilament laser beam from the same targets in air

    E-Print Network [OSTI]

    Ledingham, K W D; McCanny, T; Melone, J J; Spohr, K; Schramm, U; Kraft, S D; Wagner, A; Jochmann, A

    2011-01-01

    Over the last few years there has been much interest in the production of hard X-rays from various targets using a kHz short pulse laser at intensities above 1014Wcm-2 (A). Most of these studies have been carried out in vacuum and very many fewer studies have been carried out in air. Recently this lack has been partially addressed with the development of femtosecond laser micromachining. Another similar although apparently unconnected field (B) deals with the channelling of high power laser beam in filaments after passage through long distances in air. This has been largely driven by the construction of a mobile terawatt laser beam (Teramobile) for atmospheric studies. The laser beams in these two cases (A and B) have very different pulse energies (mJ against J) although the filaments in (B) have similar energies to (A) and are clamped at intensities less than 1014 Wcm-2. This paper has been written to compare the production of hard X-rays in these two cases. The conclusion is interesting that a focused sub T...

  2. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation...

  3. High repetition rate fiber and integrated waveguide femtosecond lasers

    E-Print Network [OSTI]

    Sander, Michelle Y. (Michelle Yen-Ling)

    2012-01-01

    Femtosecond lasers and the development of frequency combs have revolutionized multiple fields like metrology, spectroscopy, medical diagnostics and optical communications. However, to enable wider adoption of the technology ...

  4. Laser-induced resonance states as dynamic suppressors of ionization in high-frequency short pulses

    E-Print Network [OSTI]

    Barash, Danny

    distorted to a metastable well form; the electron either tunnels through or crosses over a potential barrier of a laser-induced resonance state, which is coupled by the pulse ramp to the ground state and acts to trap ionizing flux. PACS number s : 32.80.Rm I. INTRODUCTION The interaction of atomic electrons with intense

  5. Nonlinear laser energy depletion in laser-plasma accelerators

    E-Print Network [OSTI]

    Shadwick, B.A.

    2009-01-01

    Nonlinear laser energydepletion in laser-plasma accelerators ? B. A. Shadwick,of intense, short-pulse lasers via excitation of plasma

  6. High-intensity ion sources for accelerators with emphasis on H-beam formation and transport

    SciTech Connect (OSTI)

    Keller, Roderich [Los Alamos National Laboratory

    2009-01-01

    This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as d. c. discharge- and rf-driven multicusp sources. Penning-type and ECR-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber-. and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed. ionization mechanism, beam formation and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

  7. The effect of laser pulse duration on ICP-MS signal intensity, elemental fractionation, and detection limits

    E-Print Network [OSTI]

    Harilal, S. S.

    and alloys,7,8 geology,9 archaeology,6,10 biological samples,11 radioactive waste anal- ysis,9 etc-stoichiometric ICP-MS results, can occur during laser ablation, during transport from the ablation chamber to the ICP

  8. Eigenmode analysis of a high-gain free-electron laser based on...

    Office of Scientific and Technical Information (OSTI)

    Eigenmode analysis of a high-gain free-electron laser based on a transverse gradient undulator Citation Details In-Document Search Title: Eigenmode analysis of a high-gain...

  9. A versatile high-resolution x-ray imager (HRXI) for laser-plasma...

    Office of Scientific and Technical Information (OSTI)

    x-ray imager (HRXI) devoted to laser-plasma experiments combines two state-of-the-art technologies developed in France: a high-resolution x-ray microscope and a high-speed...

  10. High power 325 MHz vector modulators for the Fermilab High Intensity Neutrino Source (HINS)

    SciTech Connect (OSTI)

    Madrak, Robyn Leigh; Wildman, David; /Fermilab

    2008-10-01

    One of the goals of the low energy 60 MeV section of the HINS H{sup -} linac [1] is to demonstrate that a total of {approx}40 RF cavities can be powered by a single 2.5 MW, 325 MHz klystron. This requires individual vector modulators at the input of each RF cavity to independently adjust the amplitude and phase of the RF input signal during the 3.5 ms RF pulse. Two versions of vector modulators have been developed; a 500 kW device for the radiofrequency quadrupole (RFQ) and a 75 kW modulator for the RF cavities. High power tests showing the vector modulator phase and amplitude responses will be presented.

  11. High average power laser using a transverse flowing liquid host

    DOE Patents [OSTI]

    Ault, Earl R.; Comaskey, Brian J.; Kuklo, Thomas C.

    2003-07-29

    A laser includes an optical cavity. A diode laser pumping device is located within the optical cavity. An aprotic lasing liquid containing neodymium rare earth ions fills the optical cavity. A circulation system that provides a closed loop for circulating the aprotic lasing liquid into and out of the optical cavity includes a pump and a heat exchanger.

  12. High energy, high average power solid state green or UV laser

    DOE Patents [OSTI]

    Hackel, Lloyd A.; Norton, Mary; Dane, C. Brent

    2004-03-02

    A system for producing a green or UV output beam for illuminating a large area with relatively high beam fluence. A Nd:glass laser produces a near-infrared output by means of an oscillator that generates a high quality but low power output and then multi-pass through and amplification in a zig-zag slab amplifier and wavefront correction in a phase conjugator at the midway point of the multi-pass amplification. The green or UV output is generated by means of conversion crystals that follow final propagation through the zig-zag slab amplifier.

  13. High power and high repetition rate pulse generation using self injection-locking in Fabry-Perot Laser diode

    E-Print Network [OSTI]

    Wai, Ping-kong Alexander

    , but the output power is not very high. High repetition pulse generation based on nonlinear propagation of a dual1 High power and high repetition rate pulse generation using self injection-locking in Fabry-doped fiber ring lasers (ED-FRL) [2-3] are attractive methods to generate high speed pulse trains

  14. Development of high-repetition-rate laser pump/x-ray probe methodologies for synchrotron facilities

    SciTech Connect (OSTI)

    March, Anne Marie; Doumy, Gilles; Kanter, Elliot P.; Kraessig, Bertold; Southworth, Stephen H.; Attenkofer, Klaus; Kurtz, Charles A.; Young, Linda [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States); Stickrath, Andrew [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States); Chen, Lin X. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States); Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)

    2011-07-15

    We describe our implementation of a high repetition rate (54 kHz-6.5 MHz), high power (>10 W), laser system at the 7ID beamline at the Advanced Photon Source for laser pump/x-ray probe studies of optically driven molecular processes. Laser pulses at 1.06 {mu}m wavelength and variable duration (10 or 130 ps) are synchronized to the storage ring rf signal to a precision of {approx}250 fs rms. Frequency doubling and tripling of the laser radiation using nonlinear optical techniques have been applied to generate 532 and 355 nm light. We demonstrate that by combining a microfocused x-ray probe with focused optical laser radiation the requisite fluence (with <10 {mu}J/pulse) for efficient optical excitation can be readily achieved with a compact and commercial laser system at megahertz repetition rates. We present results showing the time-evolution of near-edge x-ray spectra of a well-studied, laser-excited metalloporphyrin, Ni(II)-tetramesitylporphyrin. The use of high repetition rate, short pulse lasers as pump sources will dramatically enhance the duty cycle and efficiency in data acquisition and hence capabilities for laser-pump/x-ray probe studies of ultrafast structural dynamics at synchrotron sources.

  15. A Lightweight, High-performance I/O Management Package for Data-intensive Computing

    SciTech Connect (OSTI)

    Wang, Jun

    2011-06-22

    Our group has been working with ANL collaborators on the topic ā??bridging the gap between parallel file system and local file systemā?¯ during the course of this project period. We visited Argonne National Lab -- Dr. Robert Rossā??s group for one week in the past summer 2007. We looked over our current project progress and planned the activities for the incoming years 2008-09. The PI met Dr. Robert Ross several times such as HEC FSIO workshop 08, SCā??08 and SCā??10. We explored the opportunities to develop a production system by leveraging our current prototype to (SOGP+PVFS) a new PVFS version. We delivered SOGP+PVFS codes to ANL PVFS2 group in 2008.We also talked about exploring a potential project on developing new parallel programming models and runtime systems for data-intensive scalable computing (DISC). The methodology is to evolve MPI towards DISC by incorporating some functions of Google MapReduce parallel programming model. More recently, we are together exploring how to leverage existing works to perform (1) coordination/aggregation of local I/O operations prior to movement over the WAN, (2) efficient bulk data movement over the WAN, (3) latency hiding techniques for latency-intensive operations. Since 2009, we start applying Hadoop/MapReduce to some HEC applications with LANL scientists John Bent and Salman Habib. Another on-going work is to improve checkpoint performance at I/O forwarding Layer for the Road Runner super computer with James Nuetz and Gary Gridder at LANL. Two senior undergraduates from our research group did summer internships about high-performance file and storage system projects in LANL since 2008 for consecutive three years. Both of them are now pursuing Ph.D. degree in our group and will be 4th year in the PhD program in Fall 2011 and go to LANL to advance two above-mentioned works during this winter break. Since 2009, we have been collaborating with several computer scientists (Gary Grider, John bent, Parks Fields, James Nunez, Hsing-Bung Chen, etc) from HPC5 and James Ahrens from Advanced Computing Laboratory in Los Alamos National Laboratory. We hold a weekly conference and/or video meeting on advancing works at two fronts: the hardware/software infrastructure of building large-scale data intensive cluster and research publications. Our group members assist in constructing several onsite LANL data intensive clusters. Two parties have been developing software codes and research papers together using both sidesā?? resources.

  16. Theoretical and Experimental Studies on Molybdenum and Stainless Steel Mirrors Cleaning by High Repetition Rate Laser Beam

    E-Print Network [OSTI]

    Theoretical and Experimental Studies on Molybdenum and Stainless Steel Mirrors Cleaning by High Repetition Rate Laser Beam

  17. Multielectron effects in high harmonic generation in N_2 and benzene: simulation using a non-adiabatic quantum molecular dynamics approach for laser-molecule interactions

    E-Print Network [OSTI]

    Dundas, Daniel

    2012-01-01

    A mixed quantum-classical approach is introduced which allows the dynamically response of molecules driven far from equilibrium to be modeled. This method is applied here to the interaction of molecules with intense, short-duration laser pulses. The electronic response of the molecule is described using time-dependent density functional theory (TDDFT) and the resulting Kohn-Sham equations are solved numerically using finite difference techniques in conjunction with local and global adaptations of an underlying grid in curvilinear coordinates. Using this approach, simulations can be carried out for a wide range of molecules and both all-electron and pseudopotential calculations can be performed. The approach is applied to the study of high harmonic generation in N_2 and benzene using linearly-polarized laser pulses and to the best of our knowledge, the results for benzene represent the first TDDFT calculations of high harmonic generation in benzene using linearly polarized laser pulses. For N_2 an enhancement ...

  18. MR-Guided High-Intensity Focused Ultrasound: Current Status of an Emerging Technology

    SciTech Connect (OSTI)

    Napoli, Alessandro, E-mail: napoli.alessandro@gmail.com; Anzidei, Michele, E-mail: michele.anzidei@gmail.com; Ciolina, Federica, E-mail: federica.ciolina@gmail.com; Marotta, Eugenio, E-mail: eugenio.marotta@gmail.com; Cavallo Marincola, Beatrice, E-mail: beatrice.cavalloamarincola@gmail.com; Brachetti, Giulia, E-mail: giuliabrachetti@gmail.com; Mare, Luisa Di, E-mail: luisadimare@gmail.com; Cartocci, Gaia, E-mail: gaia.cartocci@gmail.com; Boni, Fabrizio, E-mail: fabrizioboni00@gmail.com; Noce, Vincenzo, E-mail: vinc.noce@hotmail.it; Bertaccini, Luca, E-mail: lucaone84@libero.it; Catalano, Carlo, E-mail: carlo.catalano@uniroma1.it [Sapienza, University of Rome, Department of Radiological Sciences (Italy)] [Sapienza, University of Rome, Department of Radiological Sciences (Italy)

    2013-10-15

    The concept of ideal tumor surgery is to remove the neoplastic tissue without damaging adjacent normal structures. High-intensity focused ultrasound (HIFU) was developed in the 1940s as a viable thermal tissue ablation approach. In clinical practice, HIFU has been applied to treat a variety of solid benign and malignant lesions, including pancreas, liver, prostate, and breast carcinomas, soft tissue sarcomas, and uterine fibroids. More recently, magnetic resonance guidance has been applied for treatment monitoring during focused ultrasound procedures (magnetic resonance-guided focused ultrasound, MRgFUS). Intraoperative magnetic resonance imaging provides the best possible tumor extension and dynamic control of energy deposition using real-time magnetic resonance imaging thermometry. We introduce the fundamental principles and clinical indications of the MRgFUS technique; we also report different treatment options and personal outcomes.

  19. Left-Right Symmetric Models at the High-Intensity Frontier

    E-Print Network [OSTI]

    Castillo-Felisola, Oscar; Helo, Juan C; Kovalenko, Sergey G; Ortiz, Sebastian E

    2015-01-01

    We study constraints on Left-Right Symmetric models from searches of semileptonic decays of $D$, $D_{s}$, $B$ mesons, mediated by heavy neutrinos $N$ with masses $m_N\\sim $ GeV that go on their mass shell leading to a resonant enhancement of the rates. Using these processes we examine, as a function of $m_N$ and $M_{W_R}$, the physics reach of the recently proposed high-intensity beam dump experiment SHiP, which is expected to produce a large sample of $D_s$ mesons. We compare these results with the corresponding reach of neutrinoless double beta decay experiments, as well as like-sign dilepton searches with displaced vertices at the LHC. We conclude that the SHiP experiment has clear advantages in probing the Left-Right Symmetric models for heavy neutrinos in the GeV mass range.

  20. High flux, narrow bandwidth compton light sources via extended laser-electron interactions

    DOE Patents [OSTI]

    Barty, V P

    2015-01-13

    New configurations of lasers and electron beams efficiently and robustly produce high flux beams of bright, tunable, polarized quasi-monoenergetic x-rays and gamma-rays via laser-Compton scattering. Specifically, the use of long-duration, pulsed lasers and closely-spaced, low-charge and low emittance bunches of electron beams increase the spectral flux of the Compton-scattered x-rays and gamma rays, increase efficiency of the laser-electron interaction and significantly reduce the overall complexity of Compton based light sources.

  1. High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host

    DOE Patents [OSTI]

    Comaskey, Brian J. (Walnut Creek, CA); Ault, Earl R. (Livermore, CA); Kuklo, Thomas C. (Oakdale, CA)

    2005-07-05

    A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

  2. PHYSICAL REVIEW A 81, 033828 (2010) Intracavity dynamics in high-power mode-locked fiber lasers

    E-Print Network [OSTI]

    Turitsyn, Sergei K.

    2010-01-01

    PHYSICAL REVIEW A 81, 033828 (2010) Intracavity dynamics in high-power mode-locked fiber lasers the intracavity pulse evolutions in high-power fiber lasers. It is shown that experimentally observed dynamics within a single round trip, this new generation of high-power fiber lasers depends strongly

  3. Ultra-low repetition rate mode-locked fiber laser with high-energy pulses

    E-Print Network [OSTI]

    Kobtsev, Sergei M.

    of research into passively mode- locked fiber laser with a record-setting optical length of the resonant-repetition rate high- energy picosecond pulses from a single-wall carbon nanotube mode-locked fiber laser," presented at the Optical Amplifiers and their Applications Conference (OAA 2006), Whistler, British Columbia

  4. Seeding of a soft-x-ray laser in a plasma waveguide by high harmonic generation

    E-Print Network [OSTI]

    Seeding of a soft-x-ray laser in a plasma waveguide by high harmonic generation Ping-Hsun Lin,1 University, Chia-Yi 621, Taiwan *Corresponding author: sychen@ltl.iams.sinica.edu.tw Received August 10, 2009 November 12, 2009 A strongly saturated waveguide-based optical-field-ionization soft-x-ray laser seeded

  5. Carbon dioxide UV laser-induced fluorescence in high-pressure flames

    E-Print Network [OSTI]

    Lee, Tonghun

    Carbon dioxide UV laser-induced fluorescence in high-pressure flames W.G. Bessler a , C. Schulz a; in final form 16 May 2003 Published online 10 June 2003 Abstract Laser-induced fluorescence (LIF) of carbon dioxide is investigated with excitation between 215 and 255 nm with spectrally resolved detection in 5

  6. High efficiency cholesteric liquid crystal lasers with an external stable resonator

    E-Print Network [OSTI]

    Richardson, Martin C.

    High efficiency cholesteric liquid crystal lasers with an external stable resonator Hamidreza Shirvani-Mahdavi,1,2 Shima Fardad,2 Ezeddin Mohajerani,1 and Shin-Tson Wu2* 1 Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin St., Tehran, Iran 2 College of Optics and Photonics

  7. Circularly polarized high-efficiency cholesteric liquid crystal lasers with a tunable

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Circularly polarized high-efficiency cholesteric liquid crystal lasers with a tunable nematic phase retarder Hamidreza Shirvani-Mahdavi,1,2 Ezeddin Mohajerani,1 and Shin-Tson Wu2* 1 Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin St., Tehran, Iran 2 College of Optics and Photonics

  8. Micro-engineered first wall tungsten armor for high average power laser fusion energy systems

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    Micro-engineered first wall tungsten armor for high average power laser fusion energy systems is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first is a coordinated effort to develop laser inertial fusion energy [1]. The first stage of the HAPL program

  9. Method for optical pumping of thin laser media at high average power

    DOE Patents [OSTI]

    Zapata, Luis E. (Livermore, CA); Beach, Raymond J. (Livermore, CA); Honea, Eric C. (Sunol, CA); Payne, Stephen A. (Castro Valley, CA)

    2004-07-13

    A thin, planar laser material is bonded to a light guide of an index-matched material forming a composite disk. Diode array or other pump light is introduced into the composite disk through the edges of the disk. Pump light trapped within the composite disk depletes as it multi-passes the laser medium before reaching an opposing edge of the disk. The resulting compound optical structure efficiently delivers concentrated pump light and to a laser medium of minimum thickness. The external face of the laser medium is used for cooling. A high performance cooler attached to the external face of the laser medium rejects heat. Laser beam extraction is parallel to the heat flux to minimize optical distortions.

  10. Limits of survivability and damage for optical components used in a high repetition rate visible laser

    SciTech Connect (OSTI)

    Taylor, J.R.; Stolz, C.J.; Sarginson, T.G.

    1991-10-01

    An effort is being made to understand the limits of survivability and damage for optical components exposed to a visible laser operating continuously at a high repetition rate over 4 kHz. Results of this work are reported and related to the materials and manufacturing conditions for coatings and substrates as well as defects seen at the surface under laser illumination. These results were obtained for a variety of optical coatings and conditions using lasers from the Laser Demonstration Facility, part of the Atomic Vapor Laser Isotope Separation (AVLIS) Program at LLNL. Better understanding of the reliability of optical components in this environment could lead to improvements in design and manufacture that would result in reduced size for the laser optical system and correspondingly lower costs for the facilities that can use this technology.

  11. Laser Radar Point-Target Localization at High Photon Efficiency

    E-Print Network [OSTI]

    Shapiro, Jeffrey H.

    2013-01-01

    Minimum error-probability laser radar point-target localization is analyzed, including the effects of dark counts, background counts, and target speckle. Results from preliminary table-top experiments are reported.

  12. X-Ray Radiation from Nonlinear Thomson Scattering of an Intense Femtosecond Laser on Relativistic Electrons in a Helium Plasma

    E-Print Network [OSTI]

    Umstadter, Donald

    Electrons in a Helium Plasma K. Ta Phuoc,1 A. Rousse,1,* M. Pittman,1 J. P. Rousseau,1 V. Malka,1 S a few years ago by the detection of the second and the third harmonic light of a 1:053 m laser system

  13. 600-T Magnetic Fields due to Cold Electron Flow in a simple Cu-Coil irradiated by High Power Laser pulses

    E-Print Network [OSTI]

    Zhu, Baojun; Yuan, Dawei; Li, Yanfei; Li, Fang; Liao, Guoqian; Zhao, Jiarui; Zhong, Jiayong; Xue, Feibiao; Wei, Huigang; Zhang, Kai; Han, Bo; Pei, Xiaoxing; Liu, Chang; Zhang, Zhe; Wang, Weimin; Zhu, Jianqiang; Zhao, Gang; Zhang, Jie

    2015-01-01

    A new simple mechanism due to cold electron flow to produce strong magnetic field is proposed. A 600-T strong magnetic field is generated in the free space at the laser intensity of 5.7x10^15 Wcm^-2. Theoretical analysis indicates that the magnetic field strength is proportional to laser intensity. Such a strong magnetic field offers a new experimental test bed to study laser-plasma physics, in particular, fast-ignition laser fusion research and laboratory astrophysics.

  14. Physics of Neutralization of Intense High-Energy Ion Beam Pulses by Electrons

    SciTech Connect (OSTI)

    Kaganovich, I. D.; Davidson, R. C.; Dorf, M. A.; Startsev, E. A.; Sefkow, A. B.; Lee, E. P.; Friedman, A.

    2010-04-28

    Neutralization and focusing of intense charged particle beam pulses by electrons forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self- magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the background plasma. If controlled, this physical effect can be used for optimized beam transport over long distances.

  15. A Laser System for the Spectroscopy of Highly-Charged Bismuth Ions

    E-Print Network [OSTI]

    S. Albrecht; S. Altenburg; C. Siegel; N. Herschbach; G. Birkl

    2011-08-25

    We present and characterize a laser system for the spectroscopy on highly-charged ^209Bi^82+ ions at a wavelength of 243.87 nm. For absolute frequency stabilization, the laser system is locked to a near-infra-red laser stabilized to a rubidium transition line using a transfer cavity based locking scheme. Tuning of the output frequency with high precision is achieved via a tunable rf offset lock. A sample-and-hold technique gives an extended tuning range of several THz in the UV. This scheme is universally applicable to the stabilization of laser systems at wavelengths not directly accessible to atomic or molecular resonances. We determine the frequency accuracy of the laser system using Doppler-free absorption spectroscopy of Te_2 vapour at 488 nm. Scaled to the target wavelength of 244 nm, we achieve a frequency uncertainty of \\sigma_{244nm} = 6.14 MHz (one standard deviation) over six days of operation.

  16. High energy bursts from a solid state laser operated in the heat capacity limited regime

    DOE Patents [OSTI]

    Albrecht, Georg (Livermore, CA); George, E. Victor (Livermore, CA); Krupke, William F. (Pleasanton, CA); Sooy, Walter (Pleasanton, CA); Sutton, Steven B. (Manteca, CA)

    1996-01-01

    High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes.

  17. High energy bursts from a solid state laser operated in the heat capacity limited regime

    DOE Patents [OSTI]

    Albrecht, G.; George, E.V.; Krupke, W.F.; Sooy, W.; Sutton, S.B.

    1996-06-11

    High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes. 5 figs.

  18. A high-resolution imaging X-ray crystal spectrometer for intense laser

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL(Technical Report)Asegment, largedensity (HED)

  19. A high-resolution imaging X-ray crystal spectrometer for intense laser

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL(Technical Report)Asegment, largedensity (HED)plasma

  20. High efficiency 2 micrometer laser utilizing wing-pumped Tm.sup.3+ and a laser diode array end-pumping architecture

    DOE Patents [OSTI]

    Beach, Raymond J. (Livermore, CA)

    1997-01-01

    Wing pumping a Tm.sup.3+ doped, end pumped solid state laser generates 2 .mu.m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm.sup.3+ absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm.sup.3+ because high Tm.sup.3+ concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation.

  1. High efficiency 2 micrometer laser utilizing wing-pumped Tm{sup 3+} and a laser diode array end-pumping architecture

    DOE Patents [OSTI]

    Beach, R.J.

    1997-11-18

    Wing pumping a Tm{sup 3+} doped, end pumped solid state laser generates 2 {micro}m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm{sup 3+} absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm{sup 3+} because high Tm{sup 3+} concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation. 7 figs.

  2. Simulation of the Beam Dump for a High Intensity Electron Gun

    E-Print Network [OSTI]

    Doebert, S; Lefevre, T; Pepitone, K

    2014-01-01

    The CLIC Drive Beam is a high-intensity pulsed electron beam. A test facility for the Drive Beam electron gun will soon be commissioned at CERN. In this contribution we outline the design of a beam dump / Faraday cup capable of resisting the beam’s thermal load. The test facility will operate initially up to 140 keV. At such low energies, the electrons are absorbed very close to the surface of the dump, leading to a large energy deposition density in this thin layer. In order not to damage the dump, the beam must be spread over a large surface. For this reason, a small-angled cone has been chosen. Simulations using Geant4 have been performed to estimate the distribution of energy deposition in the dump. The heat transport both within the electron pulse and between pulses has been modelled using finite element methods to check the resistance of the dump at high repetition rates. In addition, the possibility of using a moveable dump to measure the beam profile and emittance is discussed.

  3. Transcript of the workshop to discuss plans for a National High Intensity Radioactive Nuclear Beam Facility

    SciTech Connect (OSTI)

    Nitschke, J.M. (ed.)

    1989-10-19

    Following the First International Conference on Radioactive Nuclear Beams'' in Berkeley, a workshop was held on October 19, 1989 at the Lawrence Berkeley Laboratory to discuss plans for a National High Intensity Radioactive Nuclear Beam (RNB) Facility. The purpose of the workshop was -- after having discussed during the conference the physics question that can be addressed with RNBs -- to evaluate more concretely the possibilities for actually constructing such a facility in this country. It is becoming increasingly apparent that facility producing beams of radioactive nuclei with extreme neutron-to-proton ratios is of high scientific interest and technically feasible. It would allow the study of nuclear structure and astrophysical reactions very far from the line of stable nuclei, and could provide new possibilities of reaching the long-sought island of stability of superheavy nuclei. Such facilities are under advanced consideration in Japan and at CERN in Europe. This paper contains a slightly edited transcript of the tape recording that was made of the workshop.

  4. High resolution laser spectroscopy of cesium and rubidium molecules with optically induced coherence 

    E-Print Network [OSTI]

    Chen, Hui

    2006-10-30

    This work is devoted to the study of the quantum coherent effects in diatomic molecular systems by using high resolution laser spectroscopy. In particular, we have studied the rubidium diatomic molecular gaseous medium's ...

  5. A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme

    E-Print Network [OSTI]

    Razavipour, S. G.

    A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum ...

  6. High repetition rate mode-locked erbium-doped fiber lasers with complete electric field control

    E-Print Network [OSTI]

    Sickler, Jason William, 1978-

    2008-01-01

    Recent advances in fully-stabilized mode-locked laser systems are enabling many applications, including optical arbitrary waveform generation (OAWG). In this thesis work, we describe the development of high repetition-rate ...

  7. Towards manipulating relativistic laser pulses with 3D printed materials

    E-Print Network [OSTI]

    Ji, L L; Pukhov, A; Freeman, R R; Akli, K U

    2015-01-01

    Efficient coupling of intense laser pulses to solid-density matter is critical to many applications including ion acceleration for cancer therapy. At relativistic intensities, the focus has been mainly on investigating various laser beams irradiating initially flat interfaces with little or no control over the interaction. Here, we propose a novel approach that leverages recent advancements in 3D direct laser writing (DLW) of materials and high contrast lasers to manipulate the laser-matter interactions on the micro-scales. We demonstrate, via simulations, that usable intensities >10^23Wcm^(-2) could be achieved with current tabletop lasers coupled to 3D printed plasma lenses. We show that these plasma optical elements act not only as a lens to focus laser light, but also as an electromagnetic guide for secondary particle beams. These results open new paths to engineering light-matter interactions at ultra-relativistic intensities.

  8. Relay telescope for high power laser alignment system

    DOE Patents [OSTI]

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2006-09-19

    A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

  9. Highly focused and efficient terahertz radiation generation by photo-mixing of lasers in plasma in the presence of magnetic field

    SciTech Connect (OSTI)

    Malik, Anil K.; Singh, Kunwar Pal; Sajal, V.

    2014-07-15

    A mechanism of efficient and highly focused terahertz (THz) radiation generation by photo-mixing of top-hat like lasers with frequencies ?{sub 1}, ?{sub 2} and wave numbers k{sub 1}, k{sub 2} in pre-formed rippled density (corrugated) plasma is proposed. In this mechanism, intensity variation of lasers offers nonlinear ponderomotive force at frequency ?{sup ?}=?{sub 1}??{sub 2} and wave number k{sup ?}=k{sub 1}?k{sub 2} which couples with density ripples in the plasma and leads to a strong nonlinear oscillatory current that resonantly excites highly focused and intense THz radiation at frequency ?{sub UH}=?((?{sub p}{sup 2}+?{sub c}{sup 2})) (where ?{sub c} is electron cyclotron frequency). The efficiency of emitted THz radiation of the order of 15% is obtained under optimum conditions. It is observed that focus and intensity of emitted radiation can be controlled by selecting a proper profile index of the lasers, ripple parameters, and tuning of external magnetic field.

  10. Received 9 May 2015 | Accepted 9 Sep 2015 | Published 9 Oct 2015 High-intensity power-resolved radiation

    E-Print Network [OSTI]

    MacDonald, Mark

    to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed. Monitoring systems, such as fission chambers and rhodium detector systems are expensive and have limited high temperatures, corrosion, extreme radiation levels and miniaturization. In-core monitoring systems

  11. Adaptive-feedback spectral-phase control for interactions with transform-limited ultrashort high-power laser pulses

    E-Print Network [OSTI]

    Umstadter, Donald

    point of a 100-TW peak-power laser in vacuum. The spectral-phase distortion induced by the dispersion that use high-power laser pulses must be performed in vacuum in order to prevent degradation of the laserAdaptive-feedback spectral-phase control for interactions with transform-limited ultrashort high-power

  12. High power spatial single-mode quantum cascade lasers at 8.9 $\\mu$m

    E-Print Network [OSTI]

    Forget, S; Bengloan, J Y; Calligaro, M; Parillaud, O; Giovannini, Massimo; Faist, J; Sirtori, C; Forget, Sebastien; Faugeras, Clement; Bengloan, Jean Yves; Calligaro, Michel; Parillaud, Olivier; Giovannini, Marcella; Faist, Jerome; Sirtori, Carlo

    2005-01-01

    High performance of InP-based quantum cascade lasers emitting at $\\lambda$ ~ 9$\\mu$m are reported. Thick electroplated gold layer was deposited on top of the laser to improve heat dissipation. With one facet high reflection coated, the devices produce a maximum output power of 175mW at 40% duty cycle at room temperature and continuous-wave operation up to 278K.

  13. Modeling target bulk heating resulting from ultra-intense short pulse laser irradiation of solid density targets

    SciTech Connect (OSTI)

    Antici, P. [Dipartimento SBAI, Universitą di Roma ‘‘La Sapienza,’’ Via Scarpa 14-16, 00161 Roma (Italy) [Dipartimento SBAI, Universitą di Roma ‘‘La Sapienza,’’ Via Scarpa 14-16, 00161 Roma (Italy); INRS-EMT, Varennes, Québec (Canada); Istituto Nazionale di Fisica Nucleare, Via E. Fermi, 40-00044 Frascati (Italy); LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Gremillet, L. [CEA, DAM, DIF, F-91297 Arpajon (France)] [CEA, DAM, DIF, F-91297 Arpajon (France); Grismayer, T. [GoLP/Instituto de Plasmas e Fusćo Nuclear-Laboratório Associado, Instituto Superior Técnico, 1049-001 Lisboa (Portugal)] [GoLP/Instituto de Plasmas e Fusćo Nuclear-Laboratório Associado, Instituto Superior Técnico, 1049-001 Lisboa (Portugal); Mora, P. [Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France)] [Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France); Audebert, P.; Man?ic, A.; Fuchs, J. [LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France)] [LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Borghesi, M.; Cecchetti, C. A. [School of Mathematics and Physics, The Queen's University, Belfast (United Kingdom)] [School of Mathematics and Physics, The Queen's University, Belfast (United Kingdom)

    2013-12-15

    Isochoric heating of solid-density matter up to a few tens of eV is of interest for investigating astrophysical or inertial fusion scenarios. Such ultra-fast heating can be achieved via the energy deposition of short-pulse laser generated electrons. Here, we report on experimental measurements of this process by means of time- and space-resolved optical interferometry. Our results are found in reasonable agreement with a simple numerical model of fast electron-induced heating.

  14. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    SciTech Connect (OSTI)

    Rodrigues, G. Kanjilal, D.; Roy, A.; Becker, R.; Baskaran, R.

    2014-02-15

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged {sup 238}U{sup 40+} (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  15. High power 938 nanometer fiber laser and amplifier

    DOE Patents [OSTI]

    Dawson, Jay W. (Livermore, CA); Liao, Zhi Ming (Pleasanton, CA); Beach, Raymond J. (Livermore, CA); Drobshoff, Alexander D. (Livermore, CA); Payne, Stephen A. (Castro Valley, CA); Pennington, Deanna M. (Livermore, CA); Hackenberg, Wolfgang (Munich, DE); Calia, Domenico Bonaccini (Garching, DE); Taylor, Luke (Montauban de Bretagne, FR)

    2006-05-02

    An optical fiber amplifier includes a length of silica optical fiber having a core doped with neodymium, a first cladding and a second cladding each with succeeding lower refractive indices, where the first cladding diameter is less than 10 times the diameter of the core. The doping concentration of the neodymium is chosen so that the small signal absorption for 816 nm light traveling within the core is less than 15 dB/m above the other fiber losses. The amplifier is optically pumped with one laser into the fiber core and with another laser into the first cladding.

  16. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp Graduate studentScienceLaboratoryandBryanoutreach LaserLaser

  17. Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Theobald, W.; Solodov, A. A.; Stoeckl, C.; Anderson, K. S.; Beg, F. N.; Epstein, R.; Fiksel, G.; Giraldez, E. M.; Glebov, V. Yu.; Habara, H.; et al

    2014-12-12

    The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achievemore »areal densities in excess of 300 mg cm#2;-2 with a nanosecond-duration compression pulse -- the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.« less

  18. Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion

    SciTech Connect (OSTI)

    Theobald, W.; Solodov, A. A.; Stoeckl, C.; Anderson, K. S.; Beg, F. N.; Epstein, R.; Fiksel, G.; Giraldez, E. M.; Glebov, V. Yu.; Habara, H.; Ivancic, S.; Jarrott, L. C.; Marshall, F. J.; McKiernan, G.; McLean, H. S.; Mileham, C.; Nilson, P. M.; Patel, P. K.; Pérez, F.; Sangster, T. C.; Santos, J. J.; Sawada, H.; Shvydky, A.; Stephens, R. B.; Wei, M. S.

    2014-12-12

    The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achieve areal densities in excess of 300 mg cm#2;-2 with a nanosecond-duration compression pulse -- the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.

  19. High-resolution single-shot spectral monitoring of hard x-ray free-electron laser radiation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Makita, M.; Karvinen, P.; Zhu, D.; Juranic, P. N.; Grünert, J.; Cartier, S.; Jungmann-Smith, J. H.; Lemke, H. T.; Mozzanica, A.; Nelson, S.; et al

    2015-10-16

    We have developed an on-line spectrometer for hard x-ray free-electron laser (XFEL) radiation based on a nanostructured diamond diffraction grating and a bent crystal analyzer. Our method provides high spectral resolution, interferes negligibly with the XFEL beam, and can withstand the intense hard x-ray pulses at high repetition rates of >100 Hz. The spectrometer is capable of providing shot-to-shot spectral information for the normalization of data obtained in scientific experiments and optimization of the accelerator operation parameters. We have demonstrated these capabilities of the setup at the Linac Coherent Light Source, in self-amplified spontaneous emission mode at full energy ofmore »>1 mJ with a 120 Hz repetition rate, obtaining a resolving power of ?/?? > 3 × 104. In conclusion, the device was also used to monitor the effects of pulse duration down to 8 fs by analysis of the spectral spike width.« less

  20. High power laser having a trivalent liquid host

    DOE Patents [OSTI]

    Ault, Earl R.

    2005-08-16

    A laser having a lasing chamber and a semiconductor pumping device with trivalent titanium ions dissolved in a liquid host within the lasing chamber. Since the host is a liquid, it can be removed from the optical cavity when it becomes heated avoiding the inevitable optical distortion and birefringence common to glass and crystal hosts.

  1. Production of Medical Radioisotopes with High Specific Activity in Photonuclear Reactions with $?$ Beams of High Intensity and Large Brilliance

    E-Print Network [OSTI]

    D. Habs; U. Köster

    2010-09-08

    We study the production of radioisotopes for nuclear medicine in $(\\gamma,x{\\rm n}+y{\\rm p})$ photonuclear reactions or ($\\gamma,\\gamma'$) photoexcitation reactions with high flux [($10^{13}-10^{15}$)$\\gamma$/s], small diameter $\\sim (100 \\, \\mu$m$)^2$ and small band width ($\\Delta E/E \\approx 10^{-3}-10^{-4}$) $\\gamma$ beams produced by Compton back-scattering of laser light from relativistic brilliant electron beams. We compare them to (ion,$x$n$ + y$p) reactions with (ion=p,d,$\\alpha$) from particle accelerators like cyclotrons and (n,$\\gamma$) or (n,f) reactions from nuclear reactors. For photonuclear reactions with a narrow $\\gamma$ beam the energy deposition in the target can be managed by using a stack of thin target foils or wires, hence avoiding direct stopping of the Compton and pair electrons (positrons). $(\\gamma,\\gamma')$ isomer production via specially selected $\\gamma$ cascades allows to produce high specific activity in multiple excitations, where no back-pumping of the isomer to the ground state occurs. We discuss in detail many specific radioisotopes for diagnostics and therapy applications. Photonuclear reactions with $\\gamma$ beams allow to produce certain radioisotopes, e.g. $^{47}$Sc, $^{44}$Ti, $^{67}$Cu, $^{103}$Pd, $^{117m}$Sn, $^{169}$Er, $^{195m}$Pt or $^{225}$Ac, with higher specific activity and/or more economically than with classical methods. This will open the way for completely new clinical applications of radioisotopes. For example $^{195m}$Pt could be used to verify the patient's response to chemotherapy with platinum compounds before a complete treatment is performed. Also innovative isotopes like $^{47}$Sc, $^{67}$Cu and $^{225}$Ac could be produced for the first time in sufficient quantities for large-scale application in targeted radionuclide therapy.

  2. High-resolution multi-MeV x-ray radiography using relativistic laser-solid interaction

    SciTech Connect (OSTI)

    Courtois, C.; Compant La Fontaine, A.; Barbotin, M.; Bazzoli, S.; Brebion, D.; Bourgade, J. L.; Gazave, J.; Lagrange, J. M.; Landoas, O.; Le Dain, L.; Lefebvre, E.; Pichoff, N. [CEA, DAM, DIF, F-91297 Arpajon (France); Edwards, R.; Aedy, C.; Biddle, L.; Drew, D.; Gardner, M.; Ramsay, M.; Simons, A.; Sircombe, N. [AWE Plc., Aldermaston, Reading RG7 4PR (United Kingdom)

    2011-02-15

    When high intensity ({>=}10{sup 19} W cm{sup -2}) laser light interacts with matter, multi-MeV electrons are produced. These electrons can be utilized to generate a MeV bremsstrahlung x-ray emission spectrum as they propagate into a high-Z solid target positioned behind the interaction area. The short duration (<10 ps) and the small diameter (<500 {mu}m) of the x-ray pulse combined with the MeV x-ray spectrum offers an interesting alternative to conventional bremsstrahlung x-ray sources based on an electron accelerator used to radiograph dense, rapidly moving objects. In experiments at the Omega EP laser, a multi-MeV x-ray source is characterized consistently with number of independent diagnostics. An unfiltered x-ray dose of approximately 2 rad in air at 1 m and a source diameter of less than 350 {mu}m are inferred. Radiography of a complex and high area density (up to 61 g/cm{sup 2}) object is then performed with few hundred microns spatial resolution.

  3. Generation of Ultra-intense Gamma-ray Train by QED Harmonics

    E-Print Network [OSTI]

    Liu, Chen; Zhang, Xiaomei; Ji, Liangliang; Wang, Wenpeng; Xu, Jiancai; Zhao, Xueyan; Yi, Longqing; Shi, Yin; Zhang, Lingang; Xu, Tongjun; Pei, Zhikun; Xu, Zhizhan

    2015-01-01

    When laser intensity exceeds 10^22W/cm^2, photons with energy above MeV can be generated from high-order harmonics process in the laser-plasma interaction. We find that under such laser intensity, QED effect plays a dominating role in the radiation pattern. Contrast to the gas and relativistic HHG processes, both the occurrence and energy of gamma-ray emission produced by QED harmonics are random and QED harmonics are usually not coherent, while the property of high intensity and ultra-short duration is conserved. Our simulation shows that the period of gamma-ray train is half of the laser period and the peak intensity is 1.4e22W/cm^2. This new harmonic production with QED effects are crucial to light-matter interaction in strong field and can be verified in experiments by 10PW laser facilities in the near future.

  4. Laser spectroscopy of hyperfine structure in highly-charged ions: a test of QED at high fields

    E-Print Network [OSTI]

    D. F. A. Winters; M. Vogel; D. M. Segal; R. C. Thompson; W. Noertershaeuser

    2007-04-26

    An overview is presented of laser spectroscopy experiments with cold, trapped, highly-charged ions, which will be performed at the HITRAP facility at GSI in Darmstadt (Germany). These high-resolution measurements of ground state hyperfine splittings will be three orders of magnitude more precise than previous measurements. Moreover, from a comparison of measurements of the hyperfine splittings in hydrogen- and lithium-like ions of the same isotope, QED effects at high electromagnetic fields can be determined within a few percent. Several candidate ions suited for these laser spectroscopy studies are presented.

  5. Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array

    DOE Patents [OSTI]

    Gruen, Dieter M. (Downers Grove, IL)

    2000-01-01

    A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

  6. Laminar shocks in high power laser plasma interactions

    SciTech Connect (OSTI)

    Cairns, R. A. [University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS (United Kingdom)] [University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS (United Kingdom); Bingham, R.; Norreys, P.; Trines, R. [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX (United Kingdom)] [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2014-02-15

    We propose a theory to describe laminar ion sound structures in a collisionless plasma. Reflection of a small fraction of the upstream ions converts the well known ion acoustic soliton into a structure with a steep potential gradient upstream and with downstream oscillations. The theory provides a simple interpretation of results dating back more than forty years but, more importantly, is shown to provide an explanation for recent observations on laser produced plasmas relevant to inertial fusion and to ion acceleration.

  7. Laser synchronized high-speed shutter for spectroscopic application

    DOE Patents [OSTI]

    Miles, Paul C. (Tracy, CA); Porter, Eldon L. (Tracy, CA); Prast, Thomas L. (Livermore, CA); Sunnarborg, Duane A. (Livermore, CA)

    2002-01-01

    A fast mechanical shutter, based on rotating chopper wheels, has been designed and implemented to shutter the entrance slit of a spectrograph. This device enables an exposure time of 9 .mu.s to be achieved for a 0.8 mm wide spectrograph entrance slit, achieves 100% transmission in the open state, and an essentially infinite extinction ratio. The device further incorporates chopper wheel position sensing electronics to permit the synchronous triggering of a laser source.

  8. Production of high intensity {sup 48}Ca for the 88-Inch Cyclotron and other updates

    SciTech Connect (OSTI)

    Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M. Strohmeier, M.; Thullier, T.; Todd, D.; Xie, D.; Franzen, K. Y.

    2014-02-15

    Recently the Versatile ECR for NUclear Science (VENUS) ion source was engaged in a 60-day long campaign to deliver high intensity {sup 48}Ca{sup 11+} beam to the 88-Inch Cyclotron. As the first long term use of VENUS for multi-week heavy-element research, new methods were developed to maximize oven to target efficiency. First, the tuning parameters of VENUS for injection into the cyclotron proved to be very different than those used to tune VENUS for maximum beam output of the desired charge state immediately following its bending magnet. Second, helium with no oxygen support gas was used to maximize the efficiency. The performance of VENUS and its low temperature oven used to produce the stable requested 75 e?A of {sup 48}Ca{sup 11+} beam current was impressive. The consumption of {sup 48}Ca in VENUS using the low temperature oven was checked roughly weekly, and was found to be on average 0.27 mg/h with an ionization efficiency into the 11+ charge state of 5.0%. No degradation in performance was noted over time. In addition, with the successful operation of VENUS the 88-Inch cyclotron was able to extract a record 2 p?A of {sup 48}Ca{sup 11+}, with a VENUS output beam current of 219 e?A. The paper describes the characteristics of the VENUS tune used for maximum transport efficiency into the cyclotron as well as ongoing efforts to improve the transport efficiency from VENUS into the cyclotron. In addition, we briefly present details regarding the recent successful repair of the cryostat vacuum system.

  9. High Efficiency Electron-Laser Interactions in Tapered Helical Undulators

    E-Print Network [OSTI]

    Duris, Joseph

    2015-01-01

    Demonstration of high-trapping efficiency and narrow energylaser accelerator for efficient production of high qualityand J. S. Wurtele. High-efficiency extraction of microwave

  10. Angular distributions from two-photon detachment of H- near ionization threshold: Laser-frequency and -intensity effects

    E-Print Network [OSTI]

    Chu, Shih-I; Telnov, Dmitry A.

    2002-12-18

    .80.Rm, 32.80.Gc lations @11,12#. Detailed Floquet studies of the frequency- and intensity-dependent multiphoton detachment of H2 @13# using this model potential were in good agreement with the Los Alamos experimental data @14#, as well as the two...-photon threshold @17#, again using this model poten- tial, is also in good harmony with the recent experimental work in Los Alamos @7# and Aarhus @6#, respectively. The angle-integrated multiphoton detachment rates, presented in the same work @16,17#, agree well...

  11. Impact of a high-intensity fire on mixed evergreen and mixed conifer forests in the Peninsular

    E-Print Network [OSTI]

    Deutschman, Douglas

    Impact of a high-intensity fire on mixed evergreen and mixed conifer forests in the Peninsular have changed the forest fire regime across the western United States by excluding fire. Fire conifer forest, oak woodland, chaparral and grassland. Most conifers were killed by the fire, especially

  12. Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmasa...

    E-Print Network [OSTI]

    Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy measurements of the electric E and magnetic B fields produced in laser-foil interactions and during, and dissipation of self-generated electric E and magnetic B fields by inter- actions of laser light with matter1

  13. High Spatial Resolution Laser Cavity Extinction and Laser Induced Incandescence in Low Soot Producing Flames

    E-Print Network [OSTI]

    Tian, B.; Gao, Y.; Balusamy, S.; Hochgreb, S.

    2015-06-26

    1 Introduction Soot particles generated from combustion are both a significant atmo- spheric pollutant, as well as a contributor to climate change [1–4]. Many techniques have therefore been developed to measure soot particles from a variety... ,34] is that the present technique does not rely on pulsed, shot-to-shot measurements, but rather a low power, low cost CW laser. This allows for a much simpler, less expensive system, which does not require a fast response detector and signal receiver capable of nanosec...

  14. Cladding glass ceramic for use in high powered lasers

    DOE Patents [OSTI]

    Marker, Alexander J. (Moscow, PA); Campbell, John H. (Livermore, CA)

    1998-01-01

    A Cu-doped/Fe-doped low expansion glass ceramic composition comprising in Wt. %: SiO{sub 2} 50--65; Al{sub 2}O{sub 3} 18--27; P{sub 2}O{sub 5} 0--10; Li{sub 2}O 2--6; Na{sub 2}O 0--2; K{sub 2}O 0--2; B{sub 2}O{sub 3} 0--1; MgO 0--4; ZnO 0--5; CaO 0--4; BaO 0--5; TiO{sub 2} 1--3; ZrO{sub 3} 1--3; As{sub 2}O{sub 3} 0--1.5; Sb{sub 2}O{sub 3} 0--1.5; CuO 0--3; and Fe{sub 2}O{sub 3} 0--1 wherein the total amount of SiO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} is 80--89 wt. %, and said glass ceramic contains as a dopant 0.1--3 wt. % CuO, 0.1--1 wt. % Fe{sub 2}O{sub 3} or a combined CuO+Fe{sub 2}O{sub 3} amount of 0.1--4 wt. %. The glass ceramic composition is suitable for use as a cladding material for solid laser energy storage mediums as well as for use in beam attenuators for measuring laser energy level and beam blocks or beam dumps used for absorbing excess or unused laser energy.

  15. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp Graduate studentScienceLaboratoryandBryanoutreach Laser

  16. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and- Energy Innovation PortalImpactLaser

  17. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and- Energy InnovationLaser Seeding Yields

  18. Laser Seeding Yields High-Power Coherent Terahertz Radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and- Energy InnovationLaser Seeding

  19. High-harmonic generation in plasmas from relativistic laser-electron scattering

    E-Print Network [OSTI]

    Umstadter, Donald

    High-harmonic generation in plasmas from relativistic laser-electron scattering S. Banerjee, A. R Results are presented on the generation of high harmonics through the scattering of relativistic electrons to be the emission of even- order harmonics, linear dependence on the electron density, significant amount

  20. The system for delivery of IR laser radiaton into high vacuum

    E-Print Network [OSTI]

    Abakumova, E V; Krasnov, A A; Muchnoi, N Yu; Pyata, E E

    2015-01-01

    The system for insertion of a laser beam into the vacuum chamber of high-energy storage ring is described. The main part of the system is the high-vacuum viewport for the IR radiation, based on ZnSe or GaAs crystals. The design of the viewports is presented.

  1. Highly Reproducible Laser Beam Scanning Device for an Internal Source Laser Desorption Microprobe Fourier Transform Mass Spectrometer

    SciTech Connect (OSTI)

    Scott, Jill Rennee; Tremblay, Paul Leland

    2002-03-01

    Traditionally, mass spectrometry has relied on manipulating the sample target to provide scanning capabilities for laser desorption microprobes. This has been problematic for an internal source laser desorption Fourier transform mass spectrometer (LD-FTMS) because of the high magnetic field (7 Tesla) and geometric constraints of the superconducting magnet bore. To overcome these limitations, we have implemented a unique external laser scanning mechanism for an internal source LD-FTMS. This mechanism provides adjustable resolution enhancement so that the spatial resolution at the target is not limited to that of the stepper motors at the light source (~5 µm/step). The spatial resolution is now limited by the practical optical diffraction limit of the final focusing lens. The scanning mechanism employs a virtual source that is wavelength independent up to the final focusing lens, which can be controlled remotely to account for focal length dependence on wavelength. A binary index provides an automatic alignment feature. The virtual source is located ~9 ft from the sample; therefore, it is completely outside of the vacuum system and beyond the 50 G line of the fringing magnetic field. To eliminate reproducibility problems associated with vacuum pump vibrations, we have taken advantage of the magnetic field inherent to the FTMS to utilize Lenz's law for vibrational dampening. The LD-FTMS microprobe has exceptional reproducibility, which enables successive mapping sequences for depth-profiling studies.

  2. Flexible pulse delay control up to picosecond for high-intensity twin electron bunches

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Zhen; Ding, Yuantao; Emma, Paul; Huang, Zhirong; Marinelli, Agostino; Tang, Chuanxiang

    2015-09-10

    Two closely spaced electron bunches have attracted strong interest due to their applications in two color X-ray free-electron lasers as well as witness bunch acceleration in plasmas and dielectric structures. In this paper, we propose a new scheme of delay system to vary the time delay up to several picoseconds while not affecting the bunch compression. Numerical simulations based on the Linac Coherent Light Source are performed to demonstrate the feasibility of this method.

  3. MERIT -The High Intensity Liquid Mercury Target Experiment at the CERN PS

    E-Print Network [OSTI]

    McDonald, Kirk

    placed long straight sections around the ring of the accelerator, thus creating intense neutrino beams-induced pressure waves and resulting pitting corrosion in the containment walls and cavitation formation. The use of a free flowing liquid in the form of a jet is a promising design option to address these issues

  4. Summary report of working group 3: High gradient and laser-structure based acceleration

    SciTech Connect (OSTI)

    Solyak, N.; Cowan, B.M.; /Tech-X, Boulder

    2010-01-01

    The charge for the working group on high gradient and laser-structure based acceleration was to assess the current challenges involved in developing an advanced accelerator based on electromagnetic structures, and survey state-of-the-art methods to address those challenges. The topics of more than 50 presentations in the working group covered a very broad range of issues, from ideas, theoretical models and simulations, to design and manufacturing of accelerating structures and, finally, experimental results on obtaining extremely high accelerating gradients in structures from conventional microwave frequency range up to THz and laser frequencies. Workshop discussion topics included advances in the understanding of the physics of breakdown and other phenomena, limiting high gradient performance of accelerating structures. New results presented in this workshop demonstrated significant progress in the fields of conventional vacuum structure-based acceleration, dielectric wakefield acceleration, and laser-structure acceleration.

  5. Emission parameters and thermal management of single high-power 980-nm laser diodes

    SciTech Connect (OSTI)

    Bezotosnyi, V V; Krokhin, O N; Oleshchenko, V A; Pevtsov, V F; Popov, Yu M; Cheshev, E A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2014-02-28

    We report emission parameters of high-power cw 980-nm laser diodes (LDs) with a stripe contact width of 100 ?m. On copper heat sinks of the C-mount type, a reliable output power of 10 W is obtained at a pump current of 10 A. Using a heat flow model derived from analysis of calculated and measured overall efficiencies at pump currents up to 20 A, we examine the possibility of raising the reliable power limit of a modified high-power LD mounted on heat sinks of the F-mount type using submounts with optimised geometric parameters and high thermal conductivity. The possibility of increasing the maximum reliable cw output power to 20 W with the use of similar laser crystals is discussed. (lasers)

  6. Stimulated Brillouin scattering mirror system, high power laser and laser peening method and system using same

    DOE Patents [OSTI]

    Dane, C. Brent (Livermore, CA); Hackel, Lloyd (Livermore, CA); Harris, Fritz B. (Rocklin, CA)

    2007-04-24

    A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

  7. Specification of optical components for a high average-power laser environment

    SciTech Connect (OSTI)

    Taylor, J.R.; Chow, R.; Rinmdahl, K.A.; Willis, J.B.; Wong, J.N.

    1997-06-25

    Optical component specifications for the high-average-power lasers and transport system used in the Atomic Vapor Laser Isotope Separation (AVLIS) plant must address demanding system performance requirements. The need for high performance optics has to be balanced against the practical desire to reduce the supply risks of cost and schedule. This is addressed in optical system design, careful planning with the optical industry, demonstration of plant quality parts, qualification of optical suppliers and processes, comprehensive procedures for evaluation and test, and a plan for corrective action.

  8. Nuclear astrophysics with intense photon beam

    SciTech Connect (OSTI)

    Shizuma, Toshiyuki [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2012-07-09

    Quasi-monochromatic photon beams generated by inverse Compton scattering of laser light with high energy electrons can be used for precise measurements of photoneutrons and resonant scattered {gamma} rays. Extremely high intensity and small energy spreading width of the photon beam expected at the ELI Nuclear Physics facility would increase the experimental sensitivities considerably. Possible photonuclear reaction measurements relevant to the p-process nucleosynthesis are discussed.

  9. High repetition rate laser-induced breakdown spectroscopy using acousto-optically gated detection

    SciTech Connect (OSTI)

    Po?ķzka, Pavel [BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, D-12489 Berlin (Germany); Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 61669 Brno (Czech Republic); Klessen, Benjamin; Gornushkin, Igor; Riedel, Jens [BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, D-12489 Berlin (Germany); Kaiser, Jozef [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 61669 Brno (Czech Republic); Panne, Ulrich [BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, D-12489 Berlin (Germany); Chemistry Department, Humboldt Universität zu Berlin, Brook-Taylor-Straße 2, D-12489 Berlin (Germany)

    2014-07-15

    This contribution introduces a new type of setup for fast sample analysis using laser-induced breakdown spectroscopy (LIBS). The novel design combines a high repetition rate laser (up to 50 kHz) as excitation source and an acousto-optical modulator (AOM) as a fast switch for temporally gating the detection of the emitted light. The plasma radiation is led through the active medium of the AOM where it is diffracted on the transient ultrasonic Bragg grid. The diffracted radiation is detected by a compact Czerny-Turner spectrometer equipped with a CCD line detector. Utilizing the new combination of high repetition rate lasers and AOM gated detection, rapid measurements with total integration times of only 10 ms resulted in a limit of detection (LOD) of 0.13 wt.% for magnesium in aluminum alloys. This short integration time corresponds to 100 analyses/s. Temporal gating of LIP radiation results in improved LODs and consecutively higher sensitivity of the LIBS setup. Therefore, an AOM could be beneficially utilized to temporally detect plasmas induced by high repetition rate lasers. The AOM in combination with miniaturized Czerny-Turner spectrometers equipped with CCD line detectors and small footprint diode pumped solid state lasers results in temporally gateable compact LIBS setups.

  10. Heavy and superheavy elements production in high intensive fluxes of explosive process

    E-Print Network [OSTI]

    Lutostansky, Yu S; Panov, I V

    2015-01-01

    Mathematical model of heavy and superheavy nuclei production in intensive pulsed neutron fluxes of explosive process is developed. The pulse character of the process allows dividing it in time into two stages: very short rapid process of multiple neutron captures with higher temperature and very intensive neutron fluxes, and relatively slower process with lower temperature and neutron fluxes. The model was also extended for calculation of the transuranium yields in nuclear explosions takes into account the adiabatic character of the process, the probabilities of delayed fission, and the emission of delayed neutrons. Also the binary starting target isotopes compositions were included. Calculations of heavy transuranium and transfermium nuclei production were made for Mike, Par and Barbel experiments, performed in USA. It is shown that the production of transfermium neutron-rich nuclei and superheavy elements with A ~ 295 is only possible in case of binary mixture of starting isotopes with the significant addit...

  11. 1 GeV Electron Beams from a Laser-Driven Channel-Guided Accelerator

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    energy lasers. The radiation pressure of an intense laser pulse drives a space charge wave in a plasma [1 particle accelerators for radiation sources, high-energy physics, and other applications are typically machines. A different technology for generating intense energetic electron beams and synchronized

  12. Relativistic Laser-Matter Interactions

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Relativistic Laser-Matter Interactions Relativistic Laser-Matter Interactions Enabling the next generation of intense particle accelerators Contact Juan Fernandez (505) 667-6575...

  13. Recent advances in phosphate laser glasses for high power applications. Revision 1

    SciTech Connect (OSTI)

    Campbell, J.H.

    1996-05-01

    Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bulk glass absorption have been carefully measured and can be accurately predicted. Improvements in processing have lead to high damage threshold (e.g. Pt inclusion free) and high thermal shock resistant glasses with improved edge claddings. High optical quality pieces up to 79 x 45 x 4 cm{sup 3} have been made and methods for continuous melting laser glass are under development.

  14. High peak-power kilohertz laser system employing single-stage multi-pass amplification

    DOE Patents [OSTI]

    Shan, Bing; Wang, Chun; Chang, Zenghu

    2006-05-23

    The present invention describes a technique for achieving high peak power output in a laser employing single-stage, multi-pass amplification. High gain is achieved by employing a very small "seed" beam diameter in gain medium, and maintaining the small beam diameter for multiple high-gain pre-amplification passes through a pumped gain medium, then leading the beam out of the amplifier cavity, changing the beam diameter and sending it back to the amplifier cavity for additional, high-power amplification passes through the gain medium. In these power amplification passes, the beam diameter in gain medium is increased and carefully matched to the pump laser's beam diameter for high efficiency extraction of energy from the pumped gain medium. A method of "grooming" the beam by means of a far-field spatial filter in the process of changing the beam size within the single-stage amplifier is also described.

  15. High repetition rate, high average power, femtosecond erbium fiber ring laser

    E-Print Network [OSTI]

    Ippen, Erich P.

    A 301 MHz fundamentally mode-locked erbium fiber ring laser generating 108 fs pulses is demonstrated. Novel combination of gain fiber with anomalous group-velocity dispersion and intra-cavity silicon with normal group-velocity ...

  16. Enhancement of high-harmonic generation by laser-induced cluster vibration

    E-Print Network [OSTI]

    Enhancement of high-harmonic generation by laser-induced cluster vibration Yen-Mu Chen,1,2 Ming a new tool for studying the vibrational dynamics of nanometer atomic clusters. Ā© 2007 Optical Society vibration was reported [8], and the results indicate that HHG is a very sensitive probe for vibrational

  17. High Average Power Operation of a Scraper-Outcoupled Free-Electron Laser

    SciTech Connect (OSTI)

    Michelle D. Shinn; Chris Behre; Stephen Vincent Benson; Michael Bevins; Don Bullard; James Coleman; L. Dillon-Townes; Tom Elliott; Joe Gubeli; David Hardy; Kevin Jordan; Ronald Lassiter; George Neil; Shukui Zhang

    2004-08-01

    We describe the design, construction, and operation of a high average power free-electron laser using scraper outcoupling. Using the FEL in this all-reflective configuration, we achieved approximately 2 kW of stable output at 10 um. Measurements of gain, loss, and output mode will be compared with our models.

  18. Optimization of EUV laser and discharge devices for high-volume manufacturing

    E-Print Network [OSTI]

    Harilal, S. S.

    Optimization of EUV laser and discharge devices for high-volume manufacturing A. Hassanein* , V for improving source brightness is to simulate the source environment in order to optimize the EUV output necessitate investigation and optimization not only of power sources but also plasma irradiation parameters

  19. High-throughput imaging of heterogeneous cell organelles with an X-ray laser

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Hantke, Max, F.

    Preprocessed detector images that were used for the paper "High-throughput imaging of heterogeneous cell organelles with an X-ray laser". The CXI file contains the entire recorded data - including both hits and blanks. It also includes down-sampled images and LCLS machine parameters. Additionally, the Cheetah configuration file is attached that was used to create the pre-processed data.

  20. High-throughput imaging of heterogeneous cell organelles with an X-ray laser

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Hantke, Max, F.

    2014-11-17

    Preprocessed detector images that were used for the paper "High-throughput imaging of heterogeneous cell organelles with an X-ray laser". The CXI file contains the entire recorded data - including both hits and blanks. It also includes down-sampled images and LCLS machine parameters. Additionally, the Cheetah configuration file is attached that was used to create the pre-processed data.

  1. Attosecond laser pulse synthesis using bichromatic high-order harmonic generation Avner Fleischer and Nimrod Moiseyev

    E-Print Network [OSTI]

    Moiseyev, Nimrod

    2006 We analyze the dynamical symmetries and the selection rules relevant to the process of production of high-order harmonics as a result of irradiating an atom with strong, continuous bichromatic laser spectrum of harmonics could be a source for the production of attosecond light pulses. We demonstrate our

  2. REVIEW OF SCIENTIFIC INSTRUMENTS 83, 043101 (2012) High passive-stability diode-laser design for use

    E-Print Network [OSTI]

    Steck, Daniel A.

    2012-01-01

    -laser system optimized for high stability, low passive spectral linewidth, low cost, and ease of in-house assemREVIEW OF SCIENTIFIC INSTRUMENTS 83, 043101 (2012) High passive-stability diode-laser design-frequency mechanical resonances. The cavity is vacuum sealed, and a custom-molded silicone external housing further

  3. High-order temporal coherences of chaotic and laser light

    E-Print Network [OSTI]

    Berggren, Karl K.

    We demonstrate a new approach to measuring high-order temporal coherences that uses a four-element superconducting nanowire single-photon detector. The four independent, interleaved single-photon-sensitive elements parse ...

  4. Radiofrequency Initiation and Radiofrequency Sustainment of Laser Initiated Seeded High

    E-Print Network [OSTI]

    Scharer, John E.

    radiofrequency initiation of high pressure(l-70 Ton) inductive plasma discharges in argon, nitrogen, air, decontaminating environmental waste and gaseous pollution. The ap- plication of these plasma sources require

  5. Science on high-energy lasers: From today to the NIF

    SciTech Connect (OSTI)

    Lee, R.W.; Petrasso, R.; Falcone, R.W.

    1995-01-01

    This document presents both a concise definition of the current capabilities of high energy lasers and a description of capabilities of the NIF (National Ignition Facility). Five scientific areas are discussed (Astrophysics, Hydrodynamics, Material Properties, Plasma Physics, Radiation Sources, and Radiative Properties). In these five areas we project a picture of the future based on investigations that are being carried on today. Even with this very conservative approach we find that the development of new higher energy lasers will make many extremely exciting areas accessible to us.

  6. Low Beat-Noise, Highly Polarized Tunable Fiber Ring Laser H. L. Liu, H. Y. Tam, W. H. Chung,

    E-Print Network [OSTI]

    Wai, Ping-kong Alexander

    , Hong Kong, China N. Sugimoto Asahi Glass Co., Ltd, 1150 Hazawa-cho, Yokohama 221-8755, Japan Abstract. However, intensity noise from these fiber ring structures, especially beat-noise which is generated beat-noise, polarized traveling wave tunable fiber ring laser. The Bi-EDF is pumped by one 1480 nm

  7. Advances in Micro-Scale Laser Peening Technology Y. Lawrence Yao, Wenwu Zhang, and Hongqiang Chen

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    . In modeling improvements, plasma expansion is modeled as laser supported combustion wave, in which radial laser supported combustion (LSC) wave [3]. The 1D results are then modified to consider spatial by an intense (>1GW/cm2 ) laser pulse, the surface layer instantane- ously vaporizes into a high temperature

  8. Ultrashort pulse high repetition rate laser system for biological tissue processing

    DOE Patents [OSTI]

    Neev, Joseph (Laguna Beach, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Glinsky, Michael E. (Livermore, CA); Stuart, Brent C. (Fremont, CA); Perry, Michael D. (Livermore, CA); Feit, Michael D. (Livermore, CA); Rubenchik, Alexander M. (Livermore, CA)

    1998-01-01

    A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.

  9. High-intracavity-power thin-disk laser for the alignment of molecules

    E-Print Network [OSTI]

    Deppe, Bastian; Kränkel, Christian; Küpper, Jochen

    2015-01-01

    We propose a novel approach for strong alignment of gas-phase molecules for experiments at arbitrary repetition rates. A high-intracavity-power continuous-wave laser will provide the necessary ac electric field of $\\!10^{10}$- $10^{11}~\\text{W}/\\text{cm}^2$. We demonstrate thin-disk lasers based on Yb:YAG and Yb:Lu$_2$O$_3$ in a linear high-finesse resonator providing intracavity power levels in excess of 100~kW at pump power levels on the order of 50~W. The multi-longitudinal-mode operation of this laser avoids spatial-hole burning even in a linear standing-wave resonator. The system will be scaled up as in-vacuum system to allow for the generation of fields of $10^{11}~\\text{W}/\\text{cm}^2$. This system will be directly applicable for experiments at modern X-ray light sources, such as synchrotrons or free-electron lasers, which operate at various very high repetition rates. This would allow to record molecular movies through temporally resolved diffractive imaging of fixed-in-space molecules, as well as the...

  10. Ultrashort pulse high repetition rate laser system for biological tissue processing

    DOE Patents [OSTI]

    Neev, J.; Da Silva, L.B.; Matthews, D.L.; Glinsky, M.E.; Stuart, B.C.; Perry, M.D.; Feit, M.D.; Rubenchik, A.M.

    1998-02-24

    A method and apparatus are disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment. 8 figs.

  11. A high-power 626 nm diode laser system for Beryllium ion trapping

    E-Print Network [OSTI]

    H. Ball; M. W. Lee; S. D. Gensemer; M. J. Biercuk

    2013-04-07

    We describe a high-power, frequency-tunable, external cavity diode laser (ECDL) system near 626 nm useful for laser cooling of trapped $^9$Be$^+$ ions. A commercial single-mode laser diode with rated power output of 170 mW at 635 nm is cooled to $\\approx - 31$ C, and a single longitudinal mode is selected via the Littrow configuration. In our setup, involving multiple stages of thermoelectric cooling, we are able to obtain $\\approx$130 mW near 626 nm, sufficient for efficient frequency doubling to the required Doppler cooling wavelengths near 313 nm in ionized Beryllium. In order to improve nonlinear frequency conversion efficiency, we achieve larger useful power via injection locking of a slave laser. In this way the entirety of the slave output power is available for frequency doubling, while analysis may be performed on the master output. We believe that this simple laser system addresses a key need in the ion trapping community and dramatically reduces the cost and complexity associated with Beryllium ion trapping experiments.

  12. Laser focus compensating sensing and imaging device

    DOE Patents [OSTI]

    Vann, C.S.

    1993-08-31

    A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a Cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the Cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the Cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a Cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

  13. Laser particle sorter

    DOE Patents [OSTI]

    Martin, J.C.; Buican, T.N.

    1987-11-30

    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  14. Use of a laser doppler vibrometer for high frequency accelerometer characterizations

    SciTech Connect (OSTI)

    Bateman, V.I.; Hansche, B.D.; Solomon, O.M.

    1995-12-31

    A laser doppler vibrometer (LDV) is being used for high frequency characterizations of accelerometers at Sandia National Laboratories (SNL). A LDV with high frequency (up to 1.5 MHz) and high velocity (10 M/s) capability was purchased from a commercial source and has been certified by the Primary Electrical Standards Department at SNL. The method used for this certification and the certification results are presented. Use of the LDV for characterization of accelerometers at high frequencies and of accelerometer sensitivity to cross-axis shocks on a Hopkinson bar apparatus is discussed.

  15. Selective enhancement of resonant multiphoton ionization with strong laser fields

    E-Print Network [OSTI]

    Li, Min; Luo, Siqiang; Zhou, Yueming; Zhang, Qingbin; Lan, Pengfei; Lu, Peixiang

    2015-01-01

    High-resolution photoelectron momentum distributions of Xe atom ionized by 800-nm linearly polarized laser fields have been traced at intensities from 1.1*1013 W/cm2 to 3.5*1013 W/cm2 using velocity-map imaging techniques. At certain laser intensities, the momentum spectrum exhibits a distinct double-ring structure for low-order above-threshold ionization, which appears to be absent at lower or higher laser intensities. By investigating intensity-resolved photoelectron energy spectrum, we find that this double-ring structure originates from resonant multiphoton ionization involving multiple Rydberg states of atoms. Varying the laser intensity, we can selectively enhance multiphoton excitation of atomic Rydberg populations. The photoelectron angular distributions of multiphoton resonance are also investigated for the low-order above threshold ionization.

  16. Opportunities for chiral discrimination using high harmonic generation in tailored laser fields

    E-Print Network [OSTI]

    Smirnova, Olga; Patchkovskii, Serguei

    2015-01-01

    Chiral discrimination with high harmonic generation (cHHG method) has been introduced in the recent work by R. Cireasa et al ( Nat. Phys. 11, 654 - 658, 2015). In its original implementation, the cHHG method works by detecting high harmonic emission from randomly oriented ensemble of chiral molecules driven by elliptically polarized field, as a function of ellipticity. Here we discuss future perspectives in the development of this novel method, the ways of increasing chiral dichroism using tailored laser pulses, new detection schemes involving high harmonic phase measurements, and concentration-independent approaches. Using the example of the epoxypropane molecule C$_3$H$_6$O (also known as 1,2-propylene oxide), we show theoretically that application of two-color counter-rotating elliptically polarized laser fields yields an order of magnitude enhancement of chiral dichroism compared to single color elliptical fields. We also describe how one can introduce a new functionality to cHHG: concentration-independen...

  17. Theoretical investigation of the origin of the multipeak structure of kinetic-energy-release spectra from charge-resonance-enhanced ionization of H{sub 2}{sup +} in intense laser fields

    SciTech Connect (OSTI)

    He Haixiang; Guo Yahui [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); China and Graduate School of the Chinese Academy of Sciences, Beijing, 10039 (China); Lu Ruifeng [Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Zhang Peiyu; Han Keli; He Guozhong [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2011-09-15

    The dynamics of hydrogen molecular ions in intense laser pulses (100 fs, I = 0.77 x 10{sup 14} W/cm{sup 2} to 2.5 x 10{sup 14} W/cm{sup 2}) has been studied, and the kinetic-energy-release spectra of Coulomb explosion channel have been calculated by numerically solving the time-dependent Schroedinger equation. In a recent experiment, a multipeak structure from charge-resonance-enhanced ionization is interpreted by a vibrational 'comb' at a critical nuclear distance. We found that the peaks could not be attributed to a single vibrational level but a collective contribution of some typical vibrational states in our calculated Coulomb explosion spectra, and the main peak shifts toward the low-energy region with increasing vibrational level, which is also different from the explanation in that experiment. We have also discussed the proton's kinetic-energy-release spectra for different durations with the same laser intensity.

  18. Laser shaping of a relativistic circularly polarized pulse by laser foil interaction

    SciTech Connect (OSTI)

    Zou, D. B.; Zhuo, H. B.; Yu, T. P.; Yang, X. H.; Shao, F. Q.; Ma, Y. Y.; Yin, Y.; Ouyang, J. M.; Ge, Z. Y.; Zhang, G. B.; Wang, P.

    2013-07-15

    Laser shaping of a relativistic circularly polarized laser pulse in ultra-intense laser thin-foil interaction is investigated by theoretical analysis and particle-in-cell simulations. It is found that the plasma foil as a nonlinear optical shutter has an obvious cut-out effect on the laser temporal and spatial profiles. Two-dimensional particle-in-cell simulations show that the high intensity part of a Gaussian laser pulse can be well extracted from the whole pulse. The transmitted pulse with longitudinal steep rise front and transverse super-Gaussian profile is thus obtained which would be beneficial for the radiation pressure acceleration regime. The Rayleigh-Taylor-like instability is observed in the simulations, which destroys the foil and results in the cut-out effect of the pulse in the rise front of a circularly polarized laser.

  19. Design of a High Intensity Neutron Source for Neutron-Induced Fission Yield Studies

    E-Print Network [OSTI]

    M. Lantz; D. Gorelov; A. Jokinen; V. S. Kolhinen; A. Mattera; H. Penttilä; S. Pomp; V. Rakopoulos; S. Rinta-Antila; A. Solders

    2013-04-09

    The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyv\\"askyl\\"a, has been supplied with a new cyclotron which will provide protons of the order of 100 {\\mu}A with up to 30 MeV energy, or deuterons with half the energy and intensity. This makes it an ideal place for measurements of neutron-induced fission products from various actinides, in view of proposed future nuclear fuel cycles. The groups at Uppsala University and University of Jyv\\"askyl\\"a are working on the design of a neutron converter that will be used as neutron source in fission yield studies. The design is based on simulations with Monte Carlo codes and a benchmark measurement that was recently performed at The Svedberg Laboratory in Uppsala. In order to obtain a competitive count rate the fission targets will be placed very close to the neutron converter. The goal is to have a flexible design that will enable the use of neutron fields with different energy distributions. In the present paper, some considerations for the design of the neutron converter will be discussed, together with different scenarios for which fission targets and neutron energies to focus on.

  20. Laser ablation based fuel ignition

    DOE Patents [OSTI]

    Early, J.W.; Lester, C.S.

    1998-06-23

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

  1. Laser ablation based fuel ignition

    DOE Patents [OSTI]

    Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

    1998-01-01

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

  2. Formation of High Charge State Heavy Ion Beams with intense Space Charge

    E-Print Network [OSTI]

    Seidl, P.A.

    2011-01-01

    of Science, Office of Fusion Energy Sciences, of the U.S.of Science, Office of Fusion Energy Sciences, of the U.S.driver for inertial fusion energy would have unusually high

  3. Experimental study of magnetically confined hollow electron beams in the Tevatron as collimators for intense high-energy hadron beams

    SciTech Connect (OSTI)

    Stancari, G.; Annala, G.; Shiltsev, V.; Still, D.; Valishev, A.; Vorobiev, L.; /Fermilab

    2011-03-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable losses. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and tested at Fermilab for this purpose. It was installed in one of the Tevatron electron lenses in the summer of 2010. We present the results of the first experimental tests of the hollow-beam collimation concept on 980-GeV antiproton bunches in the Tevatron.

  4. Abstract The Accelerator Driven Systems (ADS) require high power beam (>10 MW) to irradiate the neutron production target. To mitigate the effect of the high power, and high intensity beam on the target we propose to reduce the intensity of the beam by un

    E-Print Network [OSTI]

    McDonald, Kirk

    the neutron production target. To mitigate the effect of the high power, and high intensity beam on the targetAbstract The Accelerator Driven Systems (ADS) require high power beam (>10 MW) to irradiate a High-Power Beam* M. Haj Tahar, F Meot, P. Pile, *N. Tsoupas Brookhaven National Laboratory Upton, NY

  5. High-power InGaAs/GaAs quantum-well laser with enhanced broad spectrum of stimulated emission

    SciTech Connect (OSTI)

    Wang, Huolei; Yu, Hongyan; Zhou, Xuliang; Kan, Qiang; Yuan, Lijun; Wang, Wei; Pan, Jiaoqing, E-mail: jqpan@semi.ac.cn [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China); Chen, Weixi [State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871 (China); Ding, Ying, E-mail: Ying.Ding@glasgow.ac.uk [School of Engineering, University of Glasgow, Glasgow G12 8LT (United Kingdom)

    2014-10-06

    We report the demonstration of an InGaAs/GaAs quantum well (QW) broadband stimulated emission laser with a structure that integrated a GaAs tunnel junction with two QW active regions. The laser exhibits ultrabroad lasing spectral coverage of ?51?nm at a center wavelength of 1060?nm with a total emission power of 790 mW, corresponding to a high average spectral power density of 15.5 mW/nm, under pulsed current conditions. Compared to traditional lasers, this laser with an asymmetric separate-confinement heterostructure shows broader lasing bandwidth and higher spectral power density.

  6. Plasma wakefields driven by an incoherent combination of laser pulses: A path towards high-average power laser-plasma accelerators

    SciTech Connect (OSTI)

    Benedetti, C.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2014-05-15

    The wakefield generated in a plasma by incoherently combining a large number of low energy laser pulses (i.e., without constraining the pulse phases) is studied analytically and by means of fully self-consistent particle-in-cell simulations. The structure of the wakefield has been characterized and its amplitude compared with the amplitude of the wake generated by a single (coherent) laser pulse. We show that, in spite of the incoherent nature of the wakefield within the volume occupied by the laser pulses, behind this region, the structure of the wakefield can be regular with an amplitude comparable or equal to that obtained from a single pulse with the same energy. Wake generation requires that the incoherent structures in the laser energy density produced by the combined pulses exist on a time scale short compared to the plasma period. Incoherent combination of multiple laser pulses may enable a technologically simpler path to high-repetition rate, high-average power laser-plasma accelerators, and associated applications.

  7. Plasma wakefields driven by an incoherent combination of laser pulses: a path towards high-average power laser-plasma accelerators

    SciTech Connect (OSTI)

    Benedetti, C.; Schroeder, C.B.; Esarey, E.; Leemans, W.P.

    2014-05-01

    he wakefield generated in a plasma by incoherently combining a large number of low energy laser pulses (i.e.,without constraining the pulse phases) is studied analytically and by means of fully-self-consistent particle-in-cell simulations. The structure of the wakefield has been characterized and its amplitude compared with the amplitude of the wake generated by a single (coherent) laser pulse. We show that, in spite of the incoherent nature of the wakefield within the volume occupied by the laser pulses, behind this region the structure of the wakefield can be regular with an amplitude comparable or equal to that obtained from a single pulse with the same energy. Wake generation requires that the incoherent structure in the laser energy density produced by the combined pulses exists on a time scale short compared to the plasma period. Incoherent combination of multiple laser pulses may enable a technologically simpler path to high-repetition rate, high-average power laser-plasma accelerators and associated applications.

  8. Fabrication of a microresonator-fiber assembly maintaining a high-quality factor by CO2 laser welding

    E-Print Network [OSTI]

    Fang, Zhiwei; Wang, Min; Liu, Zhengming; Yao, Jinping; Qiao, Lingling; Cheng, Ya

    2015-01-01

    We demonstrate fabrication of a microtoroid resonator of a high-quality (high-Q) factor using femtosecond laser three-dimensional (3D) micromachining. A fiber taper is reliably assembled to the microtoroid using CO2 laser welding. Specifically, we achieve a high Q-factor of 2.12*10^6 in the microresonator-fiber assembly by optimizing the contact position between the fiber taper and the microtoroid.

  9. The National Scalable Cluster Project: Three Lessons about High Performance Data Mining and Data Intensive Computing

    E-Print Network [OSTI]

    Grossman, Robert

    The National Scalable Cluster Project: Three Lessons about High Performance Data Mining and Data are becoming common. In this paper, we describe three basic lessons we have learned about data mining and data to the data. By mining data, we mean looking for patterns, changes, associations, anomalies and other

  10. Flame Surface Fractal Characteristics in Premixed Turbulent Combustion at High Turbulence Intensities

    E-Print Network [OSTI]

    Gülder, Ömer L.

    Flame Surface Fractal Characteristics in Premixed Turbulent Combustion at High Turbulence of the flame surfaces in premixed turbulent combustion, the fractal approach is considered to be one with diameters of 11.2 and 22.4 mm, with flames of propane­air with equivalence ratios of 0.8 and 1

  11. HIGH INTENSITY LINAC DRIVER FOR THE SPIRAL-2 PROJECT : DESIGN OF SUPERCONDUCTING 88 MHZ QUARTER WAVE

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . For the high-energy section of the linac, a superconducting 88 MHz Quarter Wave Resonator (beta 0.12) has been WAVE RESONATORS (BETA 0.12), POWER COUPLERS AND CRYOMODULES T. Junquera, G. Olry, H. Saugnac, J Abstract A superconducting linac driver, delivering deuterons with an energy up to 40 MeV (5 mA) and heavy

  12. MATERIAL R&D FOR HIGH-INTENSITY PROTON BEAM PROGRESS REPORT

    E-Print Network [OSTI]

    McDonald, Kirk

    strength, very low thermal expansion or high ductility #12;Experimentation with Graphite & Carbon Resilience in terms of strength/shock absorption · CTE evaluation · Stress-strain · Fatigue · Fracture Toughness and crack development/propagation ·Corrosion Resistance ·De-lamination (if a composite such as CC

  13. Secure, Efficient Data Transport and Replica Management for High-Performance Data-Intensive Computing_

    E-Print Network [OSTI]

    Chervenak, Ann

    Secure, Efficient Data Transport and Replica Management for High-Performance Data environment, we present the design and initial performance measurements of our GridFTP protocol for efficient- energy physics and climate modeling, we conclude that these applications require two fundamental data

  14. Generation of neutral atomic beams utilizing photodetachment by high power diode laser stacks

    E-Print Network [OSTI]

    O'Connor, A P; Grussie, F; Koenning, T P; Miller, K A; de Ruette, N; Stützel, J; Savin, D W; Urbain, X; Kreckel, H

    2015-01-01

    We demonstrate the use of high power diode laser stacks to photodetach fast hydrogen and carbon anions and produce ground term neutral atomic beams. We achieve photodetachment efficiencies of $\\sim$7.4\\% for H$^-$ at a beam energy of 10\\,keV and $\\sim$3.7\\% for C$^-$ at 28\\,keV. The diode laser systems used here operate at 975\\,nm and 808\\,nm, respectively, and provide high continuous power levels of up to 2\\,kW, without the need of additional enhancements like optical cavities. The alignment of the beams is straightforward and operation at constant power levels is very stable, while maintenance is minimal. We present a dedicated photodetachment setup that is suitable to efficiently neutralize the majority of stable negative ions in the periodic table.

  15. High harmonic attosecond pulse train amplification in a free electron laser

    SciTech Connect (OSTI)

    McNeil, B.W.; Sheehy, B.; Thompson, N.R.; Dunning, D.J.

    2011-03-04

    It is shown using three-dimensional simulations that the temporal structure of an attosecond pulse train, such as that generated via high harmonic generation in noble gases, may be retained in a free electron laser amplifier through to saturation using a mode-locked optical klystron configuration. At wavelengths of {approx}12 nm, a train of attosecond pulses of widths {approx}300 as with peak powers in excess of 1 GW are predicted.

  16. Generation of pseudo-high-order group velocity locked vector solitons in fiber lasers

    E-Print Network [OSTI]

    Jin, Xinxin; Li, Lei; Ge, Yanqi; Luo, Jiaolin; Zhang, Qian; Tang, Dingyuan; Shen, Deyuan; Fu, Songnian; Liu, Deming; Zhao, Luming

    2015-01-01

    We propose and experimentally demonstrate the generation of pseudo-high-order group velocity locked vector solitons (GVLVS) in a fiber laser using a SESAM as the mode locker. With the help of an external all-fiber polarization resolved system, a GVLVS with a two-humped pulse along one polarization while a single-humped pulse along the orthogonal polarization could be obtained. The phase difference between the two humps is 180 degree.

  17. Remotely-interrogated high data rate free space laser communications link

    DOE Patents [OSTI]

    Ruggiero, Anthony J. (Livermore, CA)

    2007-05-29

    A system and method of remotely extracting information from a communications station by interrogation with a low power beam. Nonlinear phase conjugation of the low power beam results in a high power encoded return beam that automatically tracks the input beam and is corrected for atmospheric distortion. Intracavity nondegenerate four wave mixing is used in a broad area semiconductor laser in the communications station to produce the return beam.

  18. Nonlinear excitation of photonikos and plasmons by high-power, short pulse lasers

    E-Print Network [OSTI]

    Levan N. Tsintsadze; Hitoshi Hojo

    2008-10-29

    Modulational excitation of longitudinal photons (photonikos) and electron Langmuir waves, as well as ion sound waves by an incoherent strong and superstrong radiation (high-power short pulse lasers, non-thermal equilibrium cosmic field radiation, etc.) in plasmas are investigated. A simultaneous generation of photonikos and plasmons are demonstrated. Furthermore, the kinetic instability is considered when a low frequency photonikos are generated alone. Growth rates of these new modes are obtained.

  19. Contribution to the numerical study of turbulence in high intensity discharge lamps

    SciTech Connect (OSTI)

    Kaziz, S.; Ben Ahmed, R.; Helali, H.; Gazzah, H.; Charrada, K. [Unite d'Etude des Milieux Ionises et Reactifs, IPEIM, 5019 route de Kairouan Monastir (Tunisia)

    2011-07-15

    We present in this paper a comparison between results obtained with a laminar and turbulent models for high-pressure mercury arc. The two models are based on the resolution of bidimensional time-dependent equations by a semi-implicit finite-element code. The numerical computation of turbulent model is solved with large eddy simulation model; this approach takes into account the various scales of turbulence by a filtering method on each scale. The results show the quantitative influence of turbulence on the flow fields and also the difference between laminar and turbulent effects on the dynamic thermal behaviour and on the characteristics of the discharge.

  20. LambdaStation: Exploiting Advance Networks In Data Intensive High Energy Physics Applications

    SciTech Connect (OSTI)

    Harvey B. Newman

    2009-09-11

    Lambda Station software implements selective, dynamic, secure path control between local storage & analysis facilities, and high bandwidth, wide-area networks (WANs). It is intended to facilitate use of desirable, alternate wide area network paths which may only be intermittently available, or subject to policies that restrict usage to specified traffic. Lambda Station clients gain awareness of potential alternate network paths via Clarens-based web services, including path characteristics such as bandwidth and availability. If alternate path setup is requested and granted, Lambda Station will configure the local network infrastructure to properly forward designated data flows via the alternate path. A fully functional implementation of Lambda Station, capable of dynamic alternate WAN path setup and teardown, has been successfully developed. A limited Lambda Station-awareness capability within the Storage Resource Manager (SRM) product has been developed. Lambda Station has been successfully tested in a number of venues, including Super Computing 2008. LambdaStation software, developed by the Fermilab team, enables dynamic allocation of alternate network paths for high impact traffic and to forward designated flows across LAN. It negotiates with reservation and provisioning systems of WAN control planes, be it based on SONET channels, demand tunnels, or dynamic circuit networks. It creates End-To-End circuit between single hosts, computer farms or networks with predictable performance characteristics, preserving QoS if supported in LAN and WAN and tied security policy allowing only specific traffic to be forwarded or received through created path. Lambda Station project also explores Network Awareness capabilities.

  1. Development of a PCI Based Data Acquisition Platform for High Intensity Accelerator Experiments

    E-Print Network [OSTI]

    T. Higuchi; H. Fujii; M. Ikeno; Y. Igarashi; E. Inoue; R. Itoh; H. Kodama; T. Murakami; M. Nakao; K. Nakayoshi; M. Saitoh; S. Shimazaki; S. Y. Suzuki; M. Tanaka; K. Tauchi; M. Yamauchi; Y. Yasu; G. Varner; Y. Nagasaka; T. Katayama; K. Watanabe; M. Ishizuka; S. Onozawa; C. J. Li

    2003-05-28

    Data logging at an upgraded KEKB accelerator or the J-PARC facility, currently under commission, requires a high density data acquisition platform with integrated data reduction CPUs. To follow market trends, we have developed a DAQ platform based on the PCI bus, a choice which permits a fast DAQ and a long expected lifetime of the system. The platform is a 9U-VME motherboard consisting of four slots for signal digitization modules, readout FIFOs for data buffering, and three PMC slots, on one of which resides a data reduction CPU. We have performed long term and thermal stability tests. The readout speed on the platform has been measured up to 125 MB/s in DMA mode.

  2. The IsoDAR High Intensity H$_2^+$ Transport and Injection Tests

    E-Print Network [OSTI]

    Alonso, Jose; Calabretta, Luciano; Campo, Daniela; Celona, Luigi; Conrad, Janet M; Day, Alexandra; Castro, Giuseppe; Labrecque, Francis; Winklehner, Daniel

    2015-01-01

    This technical report reviews the tests performed at the Best Cyclotron Systems, Inc. facility in regards to developing a cost effective ion source, beam line transport system, and acceleration system capable of high H$_2^+$ current output for the IsoDAR (Isotope Decay At Rest) experiment. We begin by outlining the requirements for the IsoDAR experiment then provide overview of the Versatile Ion Source, Low Energy Beam Transport system, spiral inflector, and cyclotron. The experimental measurements are then discussed and the results are compared with a thorough set of simulation studies. Of particular importance we note that the Versatile Ion Source (VIS) proved to be a reliable ion source capable of generating a large amount of H$_2^+$ current. The results suggest that with further upgrades, the VIS could potentially be a suitable candidate for IsoDAR. The conclusion outlines the key results from our tests and introduces the forthcoming work this technical report has motivated.

  3. High-speed photography of energetic materials and components with a copper vapor laser

    SciTech Connect (OSTI)

    Dosser, L.R.; Reed, J.W.; Stark, M.A.

    1988-01-01

    The evaluation of the properties of energetic materials, such as burn rate and ignition energy, is of primary importance in understanding their reactions and the functioning of devices containing them. One method for recording such information is high-speed photography at rates of up to 20,000 images per second. When a copper vapor laser is synchronized with the camera, laser-illuminated images can be recorded that detail the performance of a material and/or component in a manner never before possible. The laser can also be used for ignition of the energetic material, thus eliminating the need for bridgewires or electric squibs that can interfere with photography. Details of such ignitions are readily observable, and the burn rate of a material can be determined directly from the film. There are indications that information useful for the modeling of pyrotechnic reactions will become available as well. Recent results from high-speed photography of several pyrotechnic materials and devices will be presented. 9 figs.

  4. Sub-femtosecond electron bunches created by direct laser acceleration in a laser wakefield accelerator with ionization injection

    E-Print Network [OSTI]

    Lemos, N; Marsh, K A; Joshi, C

    2015-01-01

    In this work, we will show through three-dimensional particle-in-cell simulations that direct laser acceleration in laser a wakefield accelerator can generate sub-femtosecond electron bunches. Two simulations were done with two laser pulse durations, such that the shortest laser pulse occupies only a fraction of the first bubble, whereas the longer pulse fills the entire first bubble. In the latter case, as the trapped electrons moved forward and interacted with the high intensity region of the laser pulse, micro-bunching occurred naturally, producing 0.5 fs electron bunches. This is not observed in the short pulse simulation.

  5. Quantum radiation reaction in laser-electron beam collisions

    E-Print Network [OSTI]

    T. G. Blackburn; C. P. Ridgers; J. G. Kirk; A. R. Bell

    2015-03-03

    It is possible using current high intensity laser facilities to reach the quantum radiation reaction regime for energetic electrons. An experiment using a wakefield accelerator to drive GeV electrons into a counterpropagating laser pulse would demonstrate the increase in the yield of high energy photons caused by the stochastic nature of quantum synchrotron emission: we show that a beam of $10^9$ 1 GeV electrons colliding with a 30 fs laser pulse of intensity $10^{22}~\\text{Wcm}^{-2}$ will emit 6300 photons with energy greater than 700 MeV, $60\\times$ the number predicted by classical theory.

  6. Evaluation of a Low Power, High Repetition-Rate Laser for MALDI M. Bromirski, A. Loboda, W. Ens, and K.G. Standing

    E-Print Network [OSTI]

    Ens, Werner

    Evaluation of a Low Power, High Repetition-Rate Laser for MALDI M. Bromirski, A. Loboda, W. Ens A compact, low-power, high repetition rate (10 kHz) laser has been tested for use in MALDI in a conventional rate produces detector saturation. The use of a lower power laser focused to a smaller spot may

  7. High passive-stability diode-laser design for use in atomic-physics experiments

    E-Print Network [OSTI]

    Cook, Eryn C; Brown-Heft, Tobias L; Garman, Jeffrey C; Steck, Daniel A

    2012-01-01

    We present the design and performance characterization of an external cavity diode-laser system optimized for high stability, low passive spectral linewidth, low cost, and ease of in-house assembly. The main cavity body is machined from a single aluminum block for robustness to temperature changes and mechanical vibrations, and features a stiff and light diffraction-grating arm to suppress low-frequency mechanical resonances. The cavity is vacuum-sealed, and a custom-molded silicone external housing further isolates the system from acoustic noise and temperature fluctuations. Beam shaping, optical isolation, and fiber coupling are integrated, and the design is easily adapted to many commonly used wavelengths. Resonance data, passive-linewidth data, and passive stability characterization of the new design demonstrate that its performance exceeds published specifications for commercial precision diode-laser systems. The design is fully documented and freely available.

  8. Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance

    E-Print Network [OSTI]

    D. Habs; M. Gross; P. G. Thirolf; P. Böni

    2010-09-30

    We propose to search for neutron halo isomers populated via $\\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\\gamma$-beams of high intensity and small band width ($\\le$ 0.1%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \\cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\\gamma$-decay back to the ground state in the 100 ps-$\\mu$s range. Similar to the treatment of photodisintegration of the deuteron, the neutron release from the neutron halo isomer via a second, low-energy, intense photon beam has a known much larger cross section with a typical energy threshold behavior. In the second step, the neutrons can be released as a low-energy, pulsed, polarized neutron beam of high intensity and high brilliance, possibly being much superior to presently existing beams from reactors or spallation neutron sources.

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

    E-Print Network [OSTI]

    Jin, Cheng

    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 ...

  10. Backward air lasing actions induced by femtosecond laser filamentation: influence of population inversion lifetime

    E-Print Network [OSTI]

    Xie, Hongqiang; chu, Wei; Zeng, Bin; Yao, Jinping; Jing, Chenrui; Li, Ziting; Cheng, Ya

    2015-01-01

    We experimentally investigate generation of backward 357 nm N2 laser in a gas mixture of N2/Ar using 800-nm femtosecond laser pulses, and examine the involved gain dynamics based on pump-probe measurements. Our findings show that a minimum lifetime of population inversion in the excited N2 molecules is required for generating intense backward nitrogen lasers, which is ~0.8 ns under our experimental conditions. The results shed new light on the mechanism for generating intense backward lasers from ambient air, which are highly in demand for high sensitivity remote atmospheric sensing application.

  11. Edge-facet pumped, multi-aperture, thin-disk laser geometry for very high average power output scaling

    DOE Patents [OSTI]

    Zapata, Luis E.

    2004-12-21

    The average power output of a laser is scaled, to first order, by increasing the transverse dimension of the gain medium while increasing the thickness of an index matched light guide proportionately. Strategic facets cut at the edges of the laminated gain medium provide a method by which the pump light introduced through edges of the composite structure is trapped and passes through the gain medium repeatedly. Spontaneous emission escapes the laser volume via these facets. A multi-faceted disk geometry with grooves cut into the thickness of the gain medium is optimized to passively reject spontaneous emission generated within the laser material, which would otherwise be trapped and amplified within the high index composite disk. Such geometry allows the useful size of the laser aperture to be increased, enabling the average laser output power to be scaled.

  12. High-power beam injectors for 100 KW free-electron lasers

    SciTech Connect (OSTI)

    Todd, A. M.; Wood R. L.; Bluem, H.; Young, L. M.; Wiseman, M.; Schultheiss, T.; Schrage, D. L.; Russell, S. J.; Rode, C. H.; Rimmer, R.; Nguyen, D. C.; Kelley, J. P.; Kurennoy, S.; wood, r

    2003-01-01

    A key technology issue on the path to high-power FEL operation is the demonstration of reliable, high-brightness, high-power injector operation. We describe two ongoing programs to produce 100 mA injectors as drivers for 100 kW free-electron lasers. In one approach, in collaboration with the Thomas Jefferson National Accelerator Facility, we are fabricating a 750 MHz superconducting RF cryomodule that will be integrated with a room-temperature DC photocathode gun and tested at the Laboratory. In the other approach, in collaboration with Los Alamos National Laboratory, a high-current 700 MHz, normal-conducting, RF photoinjector is being designed and will undergo thermal management testing at the Laboratory. We describe the design, the projected performance and the status of both injectors.

  13. High Resolution Angle Resolved Photoemission with Tabletop 11eV Laser

    E-Print Network [OSTI]

    He, Yu; Yi, Ming; Yang, Shuolong; Liu, Zhongkai; Lee, James; Chen, Sudi; Rebec, Slavko; Leuenberger, Dominik; Zong, Alfred; Jefferson, Michael; Moore, Robert; Kirchmann, Patrick; Merriam, Andrew; Shen, Zhixun

    2015-01-01

    We developed a table-top vacuum ultraviolet (VUV) laser with $113.778$nm wavelength (10.897eV) and demonstrated its viability as a photon source for high resolution angle-resolved photoemission spectroscopy (ARPES). This sub-nanosecond pulsed VUV laser operates at a repetition rate of 10MHz, provides a flux of 2$\\times$10$^{12}$ photons/second, and enables photoemission with energy and momentum resolutions better than 2meV and 0.012\\AA$^{-1}$, respectively. Space-charge induced energy shifts and spectral broadenings can be reduced below 2meV. The setup reaches electron momenta up to 1.2\\AA$^{-1}$, granting full access to the first Brillouin zone of most materials. Control over the linear polarization, repetition rate, and photon flux of the VUV source facilitates ARPES investigations of a broad range of quantum materials, bridging the application gap between contemporary low energy laser-based ARPES and synchrotron-based ARPES. We describe the principles and operational characteristics of this source, and sho...

  14. Higher velocity, high-foot implosions on the National Ignition Facility laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Callahan, D. A.; Hurricane, O. A.; Hinkel, D. E.; Döppner, T.; Ma, T.; Park, H. -S.; Barrios Garcia, M. A.; Berzak Hopkins, L. F.; Casey, D. T.; Cerjan, C. J.; et al

    2015-05-15

    By increasing the velocity in “high foot” implosions [Dittrich et al., Phys. Rev. Lett. 112, 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014); Hurricane et al., Nature 506, 343 (2014); Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility laser, we have nearly doubled the neutron yield and the hotspot pressure as compared to the implosions reported upon last year. The implosion velocity has been increased using a combination of the laser (higher power and energy), the hohlraum (depleted uranium wall material with higher opacity and lower specific heat than gold hohlraums), andmore »the capsule (thinner capsules with less mass). We find that the neutron yield from these experiments scales systematically with a velocity-like parameter of the square root of the laser energy divided by the ablator mass. By connecting this parameter with the inferred implosion velocity (v), we find that for shots with primary yield >1e15 neutrons, the total yield ~ v???. This increase is considerably faster than the expected dependence for implosions without alpha heating ( ~v???) and is additional evidence that these experiments have significant alpha heating.« less

  15. Higher velocity, high-foot implosions on the National Ignition Facility laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Callahan, D. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000315498916); Hurricane, O. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hinkel, D. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Döppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ma, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, H. -S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barrios Garcia, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Berzak Hopkins, L. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000291875667); Casey, D. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cerjan, C. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000251686845); Dewald, E. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dittrich, T. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Edwards, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haan, S. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000184045131); Hamza, A. V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kline, J. L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Knauer, J. P. [Univ. of Rochester, NY (United States); Kritcher, A. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Landen, O. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); LePape, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); MacPhee, A. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000341604479); Milovich, J. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nikroo, A. [General Atomics, San Diego, CA (United States)] (ORCID:0000000288550378); Pak, A. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Patel, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rygg, J. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ralph, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Salmonson, J. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spears, B. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Springer, P. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tommasini, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benedetti, L. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bionta, R. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bond, E. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bradley, D. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Caggiano, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Field, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fittinghoff, D. N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States)] (ORCID:0000000168460378); Gatu Johnson, M. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Grim, G. P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hatarik, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Merrill, F. E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nagel, S. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000277686819); Izumi, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Khan, S. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-01

    By increasing the velocity in “high foot” implosions [Dittrich et al., Phys. Rev. Lett. 112, 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014); Hurricane et al., Nature 506, 343 (2014); Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility laser, we have nearly doubled the neutron yield and the hotspot pressure as compared to the implosions reported upon last year. The implosion velocity has been increased using a combination of the laser (higher power and energy), the hohlraum (depleted uranium wall material with higher opacity and lower specific heat than gold hohlraums), and the capsule (thinner capsules with less mass). We find that the neutron yield from these experiments scales systematically with a velocity-like parameter of the square root of the laser energy divided by the ablator mass. By connecting this parameter with the inferred implosion velocity (v), we find that for shots with primary yield >1e15 neutrons, the total yield ~ v???. This increase is considerably faster than the expected dependence for implosions without alpha heating ( ~v???) and is additional evidence that these experiments have significant alpha heating.

  16. Vacuum laser acceleration of relativistic electrons using plasma mirror injectors

    E-Print Network [OSTI]

    Thévenet, M; Kahaly, S; Vincenti, H; Vernier, A; Quéré, F; Faure, J

    2015-01-01

    Accelerating particles to relativistic energies over very short distances using lasers has been a long standing goal in physics. Among the various schemes proposed for electrons, vacuum laser acceleration has attracted considerable interest and has been extensively studied theoretically because of its appealing simplicity: electrons interact with an intense laser field in vacuum and can be continuously accelerated, provided they remain at a given phase of the field until they escape the laser beam. But demonstrating this effect experimentally has proved extremely challenging, as it imposes stringent requirements on the conditions of injection of electrons in the laser field. Here, we solve this long-standing experimental problem for the first time by using a plasma mirror to inject electrons in an ultraintense laser field, and obtain clear evidence of vacuum laser acceleration. With the advent of PetaWatt class lasers, this scheme could provide a competitive source of very high charge (nC) and ultrashort rela...

  17. Clinical Application of High-Dose, Image-Guided Intensity-Modulated Radiotherapy in High-Risk Prostate Cancer

    SciTech Connect (OSTI)

    Bayley, Andrew, E-mail: Andrew.Bayley@rmp.uhn.on.c [Radiation Medicine Program, Princess Margaret Hospital, Toronto, ON (Canada) and Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Rosewall, Tara; Craig, Tim; Bristow, Rob; Chung, Peter; Gospodarowicz, Mary; Menard, Cynthia; Milosevic, Michael; Warde, Padraig; Catton, Charles [Radiation Medicine Program, Princess Margaret Hospital, Toronto, ON (Canada) and Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada)

    2010-06-01

    Purpose: To report the feasibility and early toxicity of dose-escalated image-guided IMRT to the pelvic lymph nodes (LN), prostate (P), and seminal vesicles (SV). Methods and Materials: A total of 103 high-risk prostate cancer patients received two-phase, dose-escalated, image-guided IMRT with 3 years of androgen deprivation therapy. Clinical target volumes (CTVs) were delineated using computed tomography/magnetic resonance co-registration and included the prostate, portions of the SV, and the LN. Planning target volume margins (PTV) used were as follows: P (10 mm, 7 mm posteriorly), SV (10 mm), and LN (5 mm). Organs at risk (OaR) were the rectal and bladder walls, femoral heads, and large and small bowel. The IMRT was planned with an intended dose of 55.1 Gy in 29 fractions to all CTVs (Phase 1), with P+SV consecutive boost of 24.7 Gy in 13 fractions. Daily online image guidance was performed using bony landmarks and intraprostatic markers. Feasibility criteria included delivery of intended doses in 80% of patients, 95% of CTV displacements incorporated within PTV during Phase 1, and acute toxicity rate comparable to that of lower-dose pelvic techniques. Results: A total of 91 patients (88%) received the total prescription dose. All patients received at least 72 Gy. In Phase 1, 63 patients (61%) received the intended 55.1 Gy, whereas 87% of patients received at least 50 Gy. Dose reductions were caused by small bowel and rectal wall constraints. All CTVs received the planned dose in >95% of treatment fractions. There were no Radiation Therapy Oncology Group acute toxicities greater than Grade 3, although there were five incidences equivalent to Grade 3 within a median follow-up of 23 months. Conclusion: These results suggest that dose escalation to the PLN+P+SV using IMRT is feasible, with acceptable rates of acute toxicity.

  18. All-optical measurement of the hot electron sheath driving laser ion acceleration from thin foils

    E-Print Network [OSTI]

    Jackel, O.

    We present experimental results from an all-optical diagnostic method to directly measure the evolution of the hot-electron distribution driving the acceleration of ions from thin foils using high-intensity lasers. Central ...

  19. Effect of the plasma electrode position and shape on the beam intensity of the highly charged ions from RIKEN 18 GHz electron-cyclotron-resonance ion source

    SciTech Connect (OSTI)

    Higurashi, Y.; Nakagawa, T.; Kidera, M.; Aihara, T.; Kobayashi, K.; Kase, M.; Goto, A.; Yano, Y. [RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); SAS Ltd. Kita-shinagawa 5-9-11, Shinjuku-ku, Tokyo (Japan); RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan)

    2006-03-15

    Beam intensities of highly charged Ar ions (Ar{sup 11+,12+}) were measured as a function of plasma electrode position. We observed that the beam intensity of Ar{sup 11+,12+} increased when putting the electrode far from the electron-cyclotron-resonance zone. On the other hand, lower charged heavy ions (Ar{sup 8+,7+}) dramatically decreased. We observed that the intense beam extraction strongly affects the plasma condition. It may be due to the ion pumping effect.

  20. Interferometric adaptive optics for high-power laser beam correction in fast ignition experiments

    SciTech Connect (OSTI)

    Homoelle, D C; Baker, K L; Patel, P K; Utterback, E; Rushford, M C; Siders, C W; Barty, C J

    2009-10-22

    We present the design for a high-speed adaptive optics system that will be used to achieve the necessary laser pointing and beam-quality performance for initial fast-ignition coupling experiments. This design makes use of a 32 x 32 pixellated MEMS device as the adaptive optic and a two-channel interferometer as the wave-front sensor. We present results from a system testbed that demonstrates improvement of the Strehl ratio from 0.09 to 0.61 and stabilization of beam pointing from {approx}75{micro}rad to <2{micro}rad.

  1. High Efficiency Oxide-Confined High-Index-Contrast Broad-Area Lasers with Reduced Threshold Current Density and Improved Near-Field Profile

    E-Print Network [OSTI]

    Bowers, John

    High Efficiency Oxide-Confined High-Index-Contrast Broad-Area Lasers with Reduced Threshold Current. The poor lateral electrical and optical confinement, however, make current spreading unavoidable and lead), followed by non-selective O2-enhanced wet thermal oxidation [2] to grow a uniform thickness layer of high

  2. Practical high resolution detection method for laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Andrew J. Effenberger Jr; Jill R. Scott

    2012-02-01

    A Fabry-Perot etalon was coupled to a Czerny-Turner spectrometer to acquire high-resolution measurements in laser-induced breakdown spectroscopy (LIBS). The spectrometer was built using an inexpensive etalon coupled to a standard 0.5-m imaging spectrometer. The Hg emission doublet at 313.2 nm was used to evaluate instrument performance because it has a splitting of 29 pm. The 313.2 nm doublet was chosen due to the similar splitting seen in isotope splitting from uranium at 424.437 nm, which is 25 pm. The Hg doublet was easily resolved from a continuous source Hg-lamp with a 2 s acquisition. The doublet was also resolved in LIBS spectra of cinnabar (HgS) from the accumulation of 600 laser shots at rate of 10 Hz, or 1 min, under a helium atmosphere. In addition to observed spitting of the 313.2 nm Hg doublet, the FWHM of the 313.1844 nm line from the doublet is reported at varying He atmospheric pressures. The high performance, low cost, and compact footprint makes this system highly competitive with 2-m double pass Czerny-Turner spectrometers.

  3. Chirped pulse inverse free-electron laser vacuum accelerator

    DOE Patents [OSTI]

    Hartemann, Frederic V. (Dublin, CA); Baldis, Hector A. (Pleasanton, CA); Landahl, Eric C. (Walnut Creek, CA)

    2002-01-01

    A chirped pulse inverse free-electron laser (IFEL) vacuum accelerator for high gradient laser acceleration in vacuum. By the use of an ultrashort (femtosecond), ultrahigh intensity chirped laser pulse both the IFEL interaction bandwidth and accelerating gradient are increased, thus yielding large gains in a compact system. In addition, the IFEL resonance condition can be maintained throughout the interaction region by using a chirped drive laser wave. In addition, diffraction can be alleviated by taking advantage of the laser optical bandwidth with negative dispersion focusing optics to produce a chromatic line focus. The combination of these features results in a compact, efficient vacuum laser accelerator which finds many applications including high energy physics, compact table-top laser accelerator for medical imaging and therapy, material science, and basic physics.

  4. Simulation of power – current characteristics of high-power semiconductor lasers emitting in the range 1.5 – 1.55 ?m

    SciTech Connect (OSTI)

    Gorlachuk, P V; Ivanov, A V; Kurnosov, V D; Kurnosov, K V; Romantsevich, V I; Simakov, V A; Chernov, R V [Open Joint-Stock Company M.F. Stel'makh Polyus Research Institute, Moscow (Russian Federation)

    2014-02-28

    We report the simulation of power – current characteristics of high-power semiconductor lasers emitting in the range 1.5 – 1.55 ?m. A technique is described which allows one to determine the thermal resistance and characteristic temperatures of a laser diode. The radiative and nonradiative carrier recombination rates are evaluated. Simulation results are shown to agree well with experimental data. (lasers)

  5. Testing of Performance of Optical Fibers Under Irradiation in Intense Radiation Fields, When Subjected to Very High Temperatures

    SciTech Connect (OSTI)

    Blue, Thomas; Windl, Wolfgang; Dickerson, Bryan

    2013-01-03

    The primary objective of this project is to measure and model the performance of optical fibers in intense radiation fields when subjected to very high temperatures. This research will pave the way for fiber optic and optically based sensors under conditions expected in future high-temperature gas-cooled reactors. Sensor life and signal-to-noise ratios are susceptible to attenuation of the light signal due to scattering and absorbance in the fibers. This project will provide an experimental and theoretical study of the darkening of optical fibers in high-radiation and high-temperature environments. Although optical fibers have been studied for moderate radiation fluence and flux levels, the results of irradiation at very high temperatures have not been published for extended in-core exposures. Several previous multi-scale modeling efforts have studied irradiation effects on the mechanical properties of materials. However, model-based prediction of irradiation-induced changes in silicaĆ¢Ā?Ā?s optical transport properties has only recently started to receive attention due to possible applications as optical transmission components in fusion reactors. Nearly all damage-modeling studies have been performed in the molecular-dynamics domain, limited to very short times and small systems. Extended-time modeling, however, is crucial to predicting the long-term effects of irradiation at high temperatures, since the experimental testing may not encompass the displacement rate that the fibers will encounter if they are deployed in the VHTR. The project team will pursue such extended-time modeling, including the effects of the ambient and recrystallization. The process will be based on kinetic MC modeling using the concept of amorphous material consisting of building blocks of defect-pairs or clusters, which has been successfully applied to kinetic modeling in amorphized and recrystallized silicon. Using this procedure, the team will model compensation for rate effects, and the interplay of rate effects with the effects of annealing, to accurately predict the fibersĆ¢Ā?Ā? reliability and expected lifetime

  6. Fusion pumped laser

    DOE Patents [OSTI]

    Pappas, D.S.

    1987-07-31

    The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic field effective to generate a neutron flux of at least 10/sup 15/ neutrons/cm/sup 2//center dot/s. Conversion means are provided adjacent the fusion reactor at a location operable for converting the high-energy neutrons to an energy source with an intensity and energy effective to excite a preselected lasing medium. A lasing medium is spaced about and responsive to the energy source to generate a population inversion effective to support laser oscillations for generating output radiation. 2 figs., 2 tabs.

  7. Laser Doppler field sensor for high resolution flow velocity imaging without camera

    SciTech Connect (OSTI)

    Voigt, Andreas; Bayer, Christian; Shirai, Katsuaki; Buettner, Lars; Czarske, Juergen

    2008-09-20

    In this paper we present a laser sensor for highly spatially resolved flow imaging without using a camera. The sensor is an extension of the principle of laser Doppler anemometry (LDA). Instead of a parallel fringe system, diverging and converging fringes are employed. This method facilitates the determination of the tracer particle position within the measurement volume and leads to an increased spatial and velocity resolution compared to conventional LDA. Using a total number of four fringe systems the flow is resolved in two spatial dimensions and the orthogonal velocity component. Since no camera is used, the resolution of the sensor is not influenced by pixel size effects. A spatial resolution of 4 {mu}m in the x direction and 16 {mu}m in the y direction and a relative velocity resolution of 1x10{sup -3} have been demonstrated up to now. As a first application we present the velocity measurement of an injection nozzle flow. The sensor is also highly suitable for applications in nano- and microfluidics, e.g., for the measurement of flow rates.

  8. Control of the polarization of a vacuum-ultraviolet, high-gain, free-electron laser

    SciTech Connect (OSTI)

    Allaria, Enrico; Diviacco, Bruno; Callegari, Carlo; Finetti, Paola; Mahieu, Benoīt; Viefhaus, Jens; Zangrando, Marco; De Ninno, Giovanni; Lambert, Guillaume; Ferrari, Eugenio; Buck, Jens; Ilchen, Markus; Vodungbo, Boris; Mahne, Nicola; Svetina, Cristian; Spezzani, Carlo; Di Mitri, Simone; Penco, Giuseppe; Trovó, Mauro; Fawley, William M.; Rebernik, Primoz R.; Gauthier, David; Grazioli, Cesare; Coreno, Marcello; Ressel, Barbara; Kivimäki, Antti; Mazza, Tommaso; Glaser, Leif; Scholz, Frank; Seltmann, Joern; Gessler, Patrick; Grünert, Jan; De Fanis, Alberto; Meyer, Michael; Knie, André; Moeller, Stefan P.; Raimondi, Lorenzo; Capotondi, Flavio; Pedersoli, Emanuele; Plekan, Oksana; Danailov, Miltcho B.; Demidovich, Alexander; Nikolov, Ivaylo; Abrami, Alessandro; Gautier, Julien; Lüning, Jan; Zeitoun, Philippe; Giannessi, Luca

    2014-12-02

    The two single-pass, externally seeded free-electron lasers (FELs) of the FERMI user facility are designed around Apple-II-type undulators that can operate at arbitrary polarization in the vacuum ultraviolet-to-soft x-ray spectral range. Furthermore, within each FEL tuning range, any output wavelength and polarization can be set in less than a minute of routine operations. We report the first demonstration of the full output polarization capabilities of FERMI FEL-1 in a campaign of experiments where the wavelength and nominal polarization are set to a series of representative values, and the polarization of the emitted intense pulses is thoroughly characterized by three independent instruments and methods, expressly developed for the task. The measured radiation polarization is consistently >90% and is not significantly spoiled by the transport optics; differing, relative transport losses for horizontal and vertical polarization become more prominent at longer wavelengths and lead to a non-negligible ellipticity for an originally circularly polarized state. The results from the different polarimeter setups validate each other, allow a cross-calibration of the instruments, and constitute a benchmark for user experiments.

  9. Control of the polarization of a vacuum-ultraviolet, high-gain, free-electron laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Allaria, Enrico; Diviacco, Bruno; Callegari, Carlo; Finetti, Paola; Mahieu, Benoīt; Viefhaus, Jens; Zangrando, Marco; De Ninno, Giovanni; Lambert, Guillaume; Ferrari, Eugenio; et al

    2014-12-02

    The two single-pass, externally seeded free-electron lasers (FELs) of the FERMI user facility are designed around Apple-II-type undulators that can operate at arbitrary polarization in the vacuum ultraviolet-to-soft x-ray spectral range. Furthermore, within each FEL tuning range, any output wavelength and polarization can be set in less than a minute of routine operations. We report the first demonstration of the full output polarization capabilities of FERMI FEL-1 in a campaign of experiments where the wavelength and nominal polarization are set to a series of representative values, and the polarization of the emitted intense pulses is thoroughly characterized by three independentmore »instruments and methods, expressly developed for the task. The measured radiation polarization is consistently >90% and is not significantly spoiled by the transport optics; differing, relative transport losses for horizontal and vertical polarization become more prominent at longer wavelengths and lead to a non-negligible ellipticity for an originally circularly polarized state. The results from the different polarimeter setups validate each other, allow a cross-calibration of the instruments, and constitute a benchmark for user experiments.« less

  10. Surface composition, microstructure and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

    SciTech Connect (OSTI)

    Li, P., E-mail: pli@sqnc.edu.cn [Department of Physics and Information Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Lei, M.K., E-mail: surfeng@dlut.edu.cn [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Zhu, X.P. [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2011-06-15

    High-intensity pulsed ion beam (HIPIB) irradiation of AZ31 magnesium alloy is performed and electrochemical corrosion experiment of irradiated samples is carried out by using potentiodynamic polarization technology in order to explore the effect of HIPIB irradiation on corrosion resistance of magnesium alloy. The surface composition, cross-sectional morphology and microstructure are characterized by using electron probe microanalyzer, optical microscope and transmission electron microscope, respectively. The results indicated that HIPIB irradiation leads to a significant improvement in corrosion resistance of magnesium alloy, in terms of the considerable increase in both corrosion potential and pitting breakdown potential. The microstructural refinement and surface purification induced by HIPIB irradiation are responsible for the improved corrosion resistance. - Research Highlights: {yields} A modified layer about 30 {mu}m thick is obtained by HIPIB irradiation. {yields} Selective ablation of element/impurity phase having lower melting point is observed. {yields} More importantly, microstructural refinement occurred on the irradiated surface. {yields} The modified layer exhibited a significantly improved corrosion resistance. {yields} Improved corrosion resistance is ascribed to the combined effect induced by HIPIB.

  11. Management of Respiratory Motion in Extracorporeal High-Intensity Focused Ultrasound Treatment in Upper Abdominal Organs: Current Status and Perspectives

    SciTech Connect (OSTI)

    Muller, A., E-mail: arnaud.muller@chu-lyon.fr [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France); Petrusca, L.; Auboiroux, V. [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland)] [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland); Valette, P. J. [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France)] [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France); Salomir, R. [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland)] [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland); Cotton, F. [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France)] [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France)

    2013-12-15

    Extracorporeal high-intensity focused ultrasound (HIFU) is a minimally invasive therapy considered with increased interest for the ablation of small tumors in deeply located organs while sparing surrounding critical tissues. A multitude of preclinical and clinical studies have showed the feasibility of the method; however, concurrently they showed several obstacles, among which the management of respiratory motion of abdominal organs is at the forefront. The aim of this review is to describe the different methods that have been proposed for managing respiratory motion and to identify their advantages and weaknesses. First, we specify the characteristics of respiratory motion for the liver, kidneys, and pancreas and the problems it causes during HIFU planning, treatment, and monitoring. Second, we make an inventory of the preclinical and clinical approaches used to overcome the problem of organ motion. Third, we analyze their respective benefits and drawbacks to identify the remaining physical, technological, and clinical challenges. We thereby consider the outlook of motion compensation techniques and those that would be the most suitable for clinical use, particularly under magnetic resonance thermometry monitoring.

  12. MR-Guided High-Intensity Focused Ultrasound Ablation of Breast Cancer with a Dedicated Breast Platform

    SciTech Connect (OSTI)

    Merckel, Laura G.; Bartels, Lambertus W.; Koehler, Max O.; Bongard, H. J. G. Desiree van den; Deckers, Roel; Mali, Willem P. Th. M.; Binkert, Christoph A.; Moonen, Chrit T.; Gilhuijs, Kenneth G. A. Bosch, Maurice A. A. J. van den

    2013-04-15

    Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

  13. Increased efficiency of ion acceleration by using femtosecond laser pulses at higher harmonic frequency

    SciTech Connect (OSTI)

    Psikal, J., E-mail: jan.psikal@fjfi.cvut.cz [FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); Klimo, O. [FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); ELI-Beamlines Project, Institute of Physics of the ASCR, 18221 Prague (Czech Republic); Weber, S.; Margarone, D. [ELI-Beamlines Project, Institute of Physics of the ASCR, 18221 Prague (Czech Republic)

    2014-07-15

    The influence of laser frequency on laser-driven ion acceleration is investigated by means of two-dimensional particle-in-cell simulations. When ultrashort intense laser pulse at higher harmonic frequency irradiates a thin solid foil, the target may become re lativistically transparent for significantly lower laser pulse intensity compared with irradiation at fundamental laser frequency. The relativistically induced transparency results in an enhanced heating of hot electrons as well as increased maximum energies of accelerated ions and their numbers. Our simulation results have shown the increase in maximum proton energy and increase in the number of high-energy protons by a factor of 2 after the interaction of an ultrashort laser pulse of maximum intensity 7?×?10{sup 21?}W/cm{sup 2} with a fully ionized plastic foil of realistic density and of optimal thickness between 100?nm and 200?nm when switching from the fundamental frequency to the third harmonics.

  14. Dual effects of stochastic heating on electron injection in laser wakefield acceleration

    SciTech Connect (OSTI)

    Deng, Z. G.; Wang, X. G., E-mail: wangxg@snnu.edu.cn [Department of Physics, Zhejiang University, Hangzhou 310027 (China); School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062 (China); Yang, L. [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Zhou, C. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Ying, H. P. [Department of Physics, Zhejiang University, Hangzhou 310027 (China)

    2014-08-15

    Electron injection into the wakefield of an intense short laser pulse by a weaker laser pulse propagating in the opposite direction is reconsidered using two-dimensional (2D) particle-in-cell simulations as well as analytical modeling. It is found that for linearly polarized lasers the injection efficiency and the quality of the wakefield accelerated electrons increase with the intensity of the injection laser only up to a certain level, and then decreases. Theory and simulation tracking test electrons originally in the beat region of the two laser pulses show that the reduction of the injection efficiency at high injection-laser intensities is caused by stochastic overheating of the affected electrons.

  15. Two-gigawatt burst-mode operation of the intense microwave prototype (IMP) free-electron laser (FEL) for the microwave tokamak experiment (MTX)

    SciTech Connect (OSTI)

    Felker, B.; Allen, S.; Bell, H.

    1993-10-06

    The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the parameter space of the IMP FEL, and finally evaluate transmission and absorption in the MTX. Single-pulse operations were repeatable. After the MTX was shut down burst-mode operations were successful at 2 kHz. This paper will describe the IMP FEL, Microwave Transmission System to MTX, the diagnostics used for calorimetric measurements, and the operations of the entire Microwave system. A discussion of correlated and uncorrelated errors that affect FEL performance will be made Linear and non-linear absorption data of the microwaves in the MTX plasma will be presented.

  16. High-stability compact atomic clock based on isotropic laser cooling

    SciTech Connect (OSTI)

    Esnault, Francois-Xavier; Holleville, David; Rossetto, Nicolas; Guerandel, Stephane; Dimarcq, Noel [LNE-SYRTE, Observatoire de Paris, CNRS UPMC, 61 Avenue de l'Observatoire, 75014 Paris (France)

    2010-09-15

    We present a compact cold-atom clock configuration where isotropic laser cooling, microwave interrogation, and clock signal detection are successively performed inside a spherical microwave cavity. For ground operation, a typical Ramsey fringe width of 20 Hz has been demonstrated, limited by the atom cloud's free fall in the cavity. The isotropic cooling light's disordered properties provide a large and stable number of cold atoms, leading to a high signal-to-noise ratio limited by atomic shot noise. A relative frequency stability of 2.2x10{sup -13{tau}-1/2} has been achieved, averaged down to 4x10{sup -15} after 5x10{sup 3} s of integration. Development of such a high-performance compact clock is of major relevance for on-board applications, such as satellite-positioning systems. As a cesium clock, it opens the door to a new generation of compact primary standards and timekeeping devices.

  17. In situ high P-T Raman spectroscopy and laser heating of carbon dioxide Mario Santoro,a)

    E-Print Network [OSTI]

    Lin, Jung-Fu "Afu"

    In situ high P-T Raman spectroscopy and laser heating of carbon dioxide Mario Santoro,a) Jung interpretation of the high P-T phase diagram of carbon dioxide. Furthermore, our approach opens a new way energy of the electrons. Solid-solid phase transitions thus occur to minimize the overall energy

  18. Acute Toxicity in High-Risk Prostate Cancer Patients Treated With Androgen Suppression and Hypofractionated Intensity-Modulated Radiotherapy

    SciTech Connect (OSTI)

    Pervez, Nadeem, E-mail: nadeempe@cancerboard.ab.c [Division of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); Small, Cormac [Division of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); MacKenzie, Marc [Division of Medical Physics, Cross Cancer Institute, Edmonton, Alberta (Canada); Yee, Don; Parliament, Matthew [Division of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); Ghosh, Sunita [Division of Experimental Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); Mihai, Alina; Amanie, John; Murtha, Albert [Division of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); Field, Colin [Division of Medical Physics, Cross Cancer Institute, Edmonton, Alberta (Canada); Murray, David [Division of Experimental Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); Fallone, Gino [Division of Medical Physics, Cross Cancer Institute, Edmonton, Alberta (Canada); Pearcey, Robert, E-mail: robertpe@cancerboard.ab.c [Division of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada)

    2010-01-15

    Purpose: To report acute toxicity resulting from radiotherapy (RT) dose escalation and hypofractionation using intensity-modulated RT (IMRT) treatment combined with androgen suppression in high-risk prostate cancer patients. Methods and Materials: Sixty patients with a histological diagnosis of high-risk prostatic adenocarcinoma (having either a clinical Stage of >=T3a or an initial prostate-specific antigen [PSA] level of >=20 ng/ml or a Gleason score of 8 to 10 or a combination of a PSA concentration of >15 ng/ml and a Gleason score of 7) were enrolled. RT prescription was 68 Gy in 25 fractions (2.72 Gy/fraction) over 5 weeks to the prostate and proximal seminal vesicles. The pelvic lymph nodes and distal seminal vesicles concurrently received 45 Gy in 25 fractions. The patients were treated with helical TomoTherapy-based IMRT and underwent daily megavoltage CT image-guided verification prior to each treatment. Acute toxicity scores were recorded weekly during RT and at 3 months post-RT, using Radiation Therapy Oncology Group acute toxicity scales. Results: All patients completed RT and follow up for 3 months. The maximum acute toxicity scores were as follows: 21 (35%) patients had Grade 2 gastrointestinal (GI) toxicity; 4 (6.67%) patients had Grade 3 genitourinary (GU) toxicity; and 30 (33.33%) patients had Grade 2 GU toxicity. These toxicity scores were reduced after RT; there were only 8 (13.6%) patients with Grade 1 GI toxicity, 11 (18.97%) with Grade 1 GU toxicity, and 5 (8.62%) with Grade 2 GU toxicity at 3 months follow up. Only the V60 to the rectum correlated with the GI toxicity. Conclusion: Dose escalation using a hypofractionated schedule to the prostate with concurrent pelvic lymph node RT and long-term androgen suppression therapy is well tolerated acutely. Longer follow up for outcome and late toxicity is required.

  19. Numerical and experimental evaluation of laser forming process for the shape correction in ultra high strength steels

    SciTech Connect (OSTI)

    Song, J. H.; Lee, J.; Lee, S.; Kim, E. Z.; Lee, N. K.; Lee, G. A.; Park, S. J.; Chu, A.

    2013-12-16

    In this paper, laser forming characteristics in ultra high strength steel with ultimate strength of 1200MPa are investigated numerically and experimentally. FE simulation is conducted to identify the response related to deformation and characterize the effect of laser power, beam diameter and scanning speed with respect to the bending angle for a square sheet part. The thermo-mechanical behaviors during the straight-line heating process are presented in terms of temperature, stress and strain. An experimental setup including a fiber laser with maximum mean power of 3.0 KW is used in the experiments. From the results in this work, it would be easily adjustment the laser power and the scanning speed by controlling the line energy for a bending operation of CP1180 steel sheets.

  20. In mold laser welding for high precision polymer based optical components

    SciTech Connect (OSTI)

    Oliveira, N., E-mail: id2694@alunos.uminho.pt, E-mail: pontes@dep.uminho.pt; Pontes, A. J., E-mail: id2694@alunos.uminho.pt, E-mail: pontes@dep.uminho.pt [IPC - Institute for Polymers and Composites, Department of Polymer Engineering, University of Minho, 4800-058 Guimarćes (Portugal)

    2014-05-15

    To assemble a complete subsystem as a rear lamp, is necessary to have different machines and to perform several tasks. This necessity obliges the companies to have large structures to support all the assembling process. These huge structures are very costly and have as a consequence the reduction of the competitiveness of the companies. The process presented in this document has the intention of reducing the number of tasks needed to produce the final subsystem/product. To achieve this goal were combined several technologies, as in-mould assembling, laser welding and LEDs (light-emitting diode). One of the advantages of this process was the utilization of only one injection molding machine with three injection units to do all the assembling process. To achieve the main objective, firstly, the rear lamp was designed according to with the legislation of UNECE Vehicle Regulations - 1958 Agreements; Regulation No. 50 -Rev.2 - Position lamps, stop lamps, direction indicators for motorcycles. Posterior several polymeric materials were studied at different levels. Initial were studied several concentrations of carbon nanotubes mixed with PC (polycarbonate). This had the objective of determine, if these materials are suitable to conduct the necessary electric current to turn on the different LEDs. One of the main advantages of this process is the use of the laser transmission welded process. Since, with this welding technology is possible reduce the complexity of the final part. To understand the potentialities of this technology a combination of two materials was studied. The studied showed that all materials presented a high transparency to the laser beam. In terms of weld process, the study showed that the best welding conditions are the lowest velocity, diameter and power. With these studies was possible conclude that this new process is suitable to be implemented at the industrial level.

  1. Influence of the laser beam size on the length of a filament formed by high-power femtosecond laser radiation in air

    SciTech Connect (OSTI)

    Geints, Yu E; Zemlyanov, A A; Kabanov, A M; Matvienko, G G; Golik, S S

    2014-05-30

    The single-filamentation regime of GW femtosecond laser beams of millimetre diameter, propagating in atmospheric air under collimated and tight focusing, has been theoretically and experimentally (at wavelengths of 800 and 400 nm) investigated. The influence of the initial size of the light beam on the spatial characteristics of the filamentation region is systematically analysed. The filamentation length for collimated beams with the same initial power is found to nonmonotonically depend on the initial beam radius. In this case, the filament start point is displaced, and the longitudinal continuity of the related plasma channel is lost. For tightly focused beams, the observed filament length barely depends of the initial beam radius, provided that the peak intensity remains constant. (interaction of radiation with matter)

  2. CO{sub 2} laser pulse shortening by laser ablation of a metal target

    SciTech Connect (OSTI)

    Donnelly, T.; Mazoyer, M.; Lynch, A.; O'Sullivan, G.; O'Reilly, F.; Dunne, P.; Cummins, T. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

    2012-03-15

    A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO{sub 2} laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to {approx}2 ns and to remove the low power, long duration tails that are present in TEA CO{sub 2} pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is {approx}10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.

  3. Magnetic reconnection in high-energy-density laser-produced plasmas

    SciTech Connect (OSTI)

    Fox, W.; Bhattacharjee, A.; Germaschewski, K.

    2012-05-15

    Recently, novel experiments on magnetic reconnection have been conducted in laser-produced plasmas in a high-energy-density regime. Individual plasma bubbles self-generate toroidal, mega-gauss-scale magnetic fields through the Biermann battery effect. When multiple bubbles are created at small separation, they expand into one another, driving reconnection of this field. Reconnection in the experiments was reported to be much faster than allowed by both Sweet-Parker, and even Hall-MHD theories, when normalized to the nominal magnetic fields self-generated by single bubbles. Through particle-in-cell simulations (both with and without a binary collision operator), we model the bubble interaction at parameters and geometry relevant to the experiments. This paper discusses in detail the reconnection regime of the laser-driven experiments and reports the qualitative features of simulations. We find substantial flux-pileup effects, which boost the relevant magnetic field for reconnection in the current sheet. When this is accounted for, the normalized reconnection rates are much more in line with standard two-fluid theory of reconnection. At the largest system sizes, we additionally find that the current sheet is prone to breakup into plasmoids.

  4. Saturated 13.2 nm high-repetition-rate laser in nickellike cadmium

    E-Print Network [OSTI]

    Rocca, Jorge J.

    ps duration Ti:sap- phire laser pulses with an energy of only 1 J impinging at a grazing angle of 23 for at-wavelength metrology of extreme ultraviolet (EUV) projection li- thography optics.1 Laser laser in at-wavelength metrology of EUV optical systems composed of mul- tiple mirrors. In this Letter

  5. Laser ignition

    DOE Patents [OSTI]

    Early, James W.; Lester, Charles S.

    2004-01-13

    Sequenced pulses of light from an excitation laser with at least two resonator cavities with separate output couplers are directed through a light modulator and a first polarzing analyzer. A portion of the light not rejected by the first polarizing analyzer is transported through a first optical fiber into a first ignitor laser rod in an ignitor laser. Another portion of the light is rejected by the first polarizing analyzer and directed through a halfwave plate into a second polarization analyzer. A first portion of the output of the second polarization analyzer passes through the second polarization analyzer to a second, oscillator, laser rod in the ignitor laser. A second portion of the output of the second polarization analyzer is redirected by the second polarization analyzer to a second optical fiber which delays the beam before the beam is combined with output of the first ignitor laser rod. Output of the second laser rod in the ignitor laser is directed into the first ignitor laser rod which was energized by light passing through the first polarizing analyzer. Combined output of the first ignitor laser rod and output of the second optical fiber is focused into a combustible fuel where the first short duration, high peak power pulse from the ignitor laser ignites the fuel and the second long duration, low peak power pulse directly from the excitation laser sustains the combustion.

  6. Direct laser acceleration of electrons in free-space

    E-Print Network [OSTI]

    Carbajo, Sergio; Wong, Liang Jie; Miller, R J Dwayne; Kärtner, Franz X

    2015-01-01

    Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle accelerati...

  7. Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

    SciTech Connect (OSTI)

    Bonatto, A.; Schroeder, C.B.; Vay, J.-L.; Geddes, C.R.; Benedetti, C.; Esarey and, E.; Leemans, W.P.

    2014-07-13

    A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

  8. A Langmuir Probe Diagnostic for Use in Inhomogeneous, Time-Varying Plasmas Produced by High-Energy Laser Ablation

    SciTech Connect (OSTI)

    Patterson, J R; Emig, J A; Fournier, K B; Jenkins, P P; Trautz, K M; Seiler, S W; Davis, J F

    2012-05-01

    Langmuir probes (LP) are used extensively to characterize plasma environments produced by radio frequency, pulsed plasma thrusters, and laser ablation. We discuss here the development of a LP diagnostic to examine high-density, high-temperature inhomogeneous plasmas such as those that can be created at the University of Rochester's Laboratory for Laser Energetics OMEGA facility. We have configured our diagnostic to examine the velocity of the plasma expanding from the target. We observe velocities of approximately 16-17 cm/{micro}s, with individual LP currents displaying complex structures, perhaps due to the multiple atomic species and ionization states that exist.

  9. Laser device

    DOE Patents [OSTI]

    Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

    2007-07-10

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  10. Laser device

    DOE Patents [OSTI]

    Scott, Jill R.; Tremblay, Paul L.

    2004-11-23

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  11. Fusion pumped laser

    DOE Patents [OSTI]

    Pappas, Daniel S. (Los Alamos, NM)

    1989-01-01

    Apparatus is provided for generating energy in the form of laser radiation. A tokamak fusion reactor is provided for generating a long, or continuous, pulse of high-energy neutrons. The tokamak design provides a temperature and a magnetic field which is effective to generate a neutron flux of at least 10.sup.15 neutrons/cm.sup.2.s. A conversion medium receives neutrons from the tokamak and converts the high-energy neutrons to an energy source with an intensity and an energy effective to excite a preselected lasing medium. The energy source typically comprises fission fragments, alpha particles, and radiation from a fission event. A lasing medium is provided which is responsive to the energy source to generate a population inversion which is effective to support laser oscillations for generating output radiation.

  12. Laser frequency stabilization to highly excited state transitions using electromagnetically induced transparency in a cascade system

    E-Print Network [OSTI]

    R. P. Abel; A. K. Mohapatra; M. G. Bason; J. D. Pritchard; K. J. Weatherill; U. Raitzsch; C. S. Adams

    2009-03-05

    We demonstrate laser frequency stabilization to excited state transitions using cascade electromagnetically induced transparency (EIT). Using a room temperature Rb vapor cell as a reference, we stabilize a first diode laser to the D2 transition and a second laser to a transition from the intermediate state to a Rydberg state with principal quantum number n=19 - 70. A combined laser linewidth of 280 kHz over a 0.1 ms time period is achieved. This method may be applied generally to any cascade system and allows laser stabilization to an atomic reference in the absence of strong optical transitions.

  13. High Efficiency, Multi-Terawatt X-ray free electron lasers

    E-Print Network [OSTI]

    Emma, Claudio; Wu, Juhao; Pellegrini, Claudio

    2015-01-01

    We study high efficiency, multi-terawatt peak power, few angstrom wavelength, X-ray Free Electron Lasers (X-ray FELs). To obtain these characteristics we consider an optimized undulator design: superconducting, helical, with short period and built-in strong focusing. This design reduces the length of the breaks between modules, decreasing diffraction effects, and allows using a stronger transverse electron focusing. Both effects reduce the gain length and the overall undulator length. The peak power and efficiency depend on the transverse electron beam distribution and on time dependent effects, like synchrotron sideband growth. The last effect is identified as the main cause for reduction of electron beam microbunching and FEL peak power. We show that the optimal functional form for the undulator magnetic field tapering profile, yielding the maximum output power, depends significantly on these effects. The output power achieved when neglecting time dependent effects for an LCLS-like X-ray FEL with a 100 m lo...

  14. A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme

    SciTech Connect (OSTI)

    Razavipour, S. G. Xu, C.; Wasilewski, Z. R.; Ban, D.; Dupont, E.; Laframboise, S. R.; Chan, C. W. I.; Hu, Q.

    2014-01-27

    A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum cascade module of the device is based on a five-well GaAs/Al{sub 0.25}Ga{sub 0.75}As structure. The device lases up to 151?K with a lasing frequency of 2.67 THz. This study shows that the effect of higher energy states in carrier transport and the long-range tunnel coupling between states that belong to non-neighbouring modules have to be considered in quantum design of structures with a narrow injector barrier. Moreover, the effect of interface roughness scattering between the lasing states on threshold current is crucial.

  15. Using high-power lasers for detection of elastic photon-photon scattering

    E-Print Network [OSTI]

    E. Lundstrom; G. Brodin; J. Lundin; M. Marklund; R. Bingham; J. Collier; J. T. Mendonca; P. Norreys

    2006-02-01

    The properties of four-wave interaction via the nonlinear quantum vacuum is investigated. The effect of the quantum vacuum is to generate photons with new frequencies and wave vectors, due to elastic photon-photon scattering. An expression for the number of generated photons is derived and using state-of-the-art laser data it is found that the number of photons can reach detectable levels. In particular, the prospect of using the high repetition Astra Gemini system at the Rutherford Appleton Laboratory is discussed. The problem of noise sources is reviewed, and it is found that the noise level can be reduced well below the signal level. Thus, detection of elastic photon-photon scattering may for the first time be achieved.

  16. The Theta Laser A Low Noise Chirped Pulse Laser

    E-Print Network [OSTI]

    Van Stryland, Eric

    The Theta Laser A Low Noise Chirped Pulse Laser Dimitrios Mandridis dmandrid@creol.ucf.edu April 29, 2011 CREOL Affiliates Day 2011 #12;2 Objective: Frequency Swept (FM) Mode-locked Laser · Develop a frequency swept laser, · linear f-sweep, · uniform-intensity, · low noise, · with long-term stability

  17. Long distance nu_e -> nu_mu transitions and CP-violation with high intensity beta-beams

    E-Print Network [OSTI]

    Carlo Rubbia

    2013-06-10

    The recent experimental determinations of a large theta_13 angle have opened the way to a determination of the mass hierarchy and of the CP-violating phase. Experiments based on horn produced (anti-)neutrino conventional beams are presently under development. The event rates are marginal for a definitive search, since they require very intense beams and extremely large detector masses. Zucchelli has proposed a method in which pure (anti-)nu_e beams are generated by the beta-decay of relativistic radio-nuclides stored in a high energy storage ring pointing towards a far away neutrino detector. Since they have a much smaller transverse momentum distribution, the neutrino flux will be much more narrowly concentrated than with a horn. The isomeric doublet Li-8 (anti-nu_e, tau_1/2=0.84s) and B-8 (nu_e, tau_1/2=0.77s) has been studied. Neutrino and antineutrino beams are produced with an average transverse momentum of about 6.5 MeV/c. Radioactive ions may be generated with a dedicated table-top storage ring to supply a suitable ion source to be accelerated at high energies either at FNAL or at CERN. Ions should then extracted from the accelerator and accumulated in a decay storage ring with a long straight section pointing toward the neutrino detector. A massive detector based on liquid Argon technology is probably offering the best opportunities for such future programme. The present ICARUS LAr-TPC experiment has already collected at LNGS events in the relevant neutrino energy region. They should provide a first evidence for a conclusive experimental study of the competing signals and more generally for the actual feasibility of the beta-beam option in a search of the CP violating phase. Additional data may be provided in the near future with the ICARUS and MicroBooNe neutrino experiments located at a short distance neutrino beam and that will collect a much larger number of neutrino events.

  18. GeV electron beams from a centimeter-scale channel guided laser wakefield acceleratora...

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    GeV electron beams from a centimeter-scale channel guided laser wakefield acceleratora... K on the generation of GeV-class electron beams using an intense femtosecond laser beam and a 3.3 cm long preformed from 10­40 TW were guided over more than 20 Rayleigh ranges and high quality electron beams with energy

  19. Optical channel waveguides written by high repetition rate femtosecond laser irradiation in Li-Zn fluoroborate glass

    E-Print Network [OSTI]

    Thomas, Sunil; Solis, Javier; Biju, P R; Unnikrishnan, N V

    2015-01-01

    Low loss, optical channel waveguides have been successfully produced by high repetition rate, femtosecond laser inscription in a Li-Zn fluoroborate glass (64.9B2O3 + 25Li2O + 10ZnF2 + 0.1Er2O3). High quality waveguides were produced at 500 kHz, 1 MHz and 2 MHz laser repetition rates, showing a refractive index contrast in the range of 3-6 x 10-3 depending on various fluences. Dependence of experimental parameters such as average laser power, pulse repetition rate and writing speed on the properties of fabricated waveguides has been discussed. The comparison of optical and compositional characterization techniques evidences an enrichment of B and Zn in the guiding region, while F migrates to the heat diffused region of the written structure.

  20. VOLUME 82, NUMBER 22 P H Y S I C A L R E V I E W L E T T E R S 31 MAY 1999 Fast Compression of Laser Beams to Highly Overcritical Powers

    E-Print Network [OSTI]

    of Laser Beams to Highly Overcritical Powers V. M. Malkin, G. Shvets, and N. J. Fisch Department, wherein the laser beams are amplified to power densities much higher than a GW cm2 , even without be overcome by ultrafast com- pression of laser beams, such that highly overcritical laser powers are attained