Science.gov

Sample records for pulse radiation facility

  1. Radioactive effluent measurements at the Army Pulse Radiation Facility

    SciTech Connect

    Scherpelz, R.I.; Glissmeyer, J.A.

    1994-11-01

    Staff from the Pacific Northwest Laboratory (PNL) performed measurements of the radioactive effluents emitted by the Army Pulse Radiation Facility (APRF). These measurements were performed by collecting the cooling air that passed by the APRF reactor as it operated, passing the air through filters to collect the particulates and iodines, and collecting samples of the air to be analyzed for noble gases. The reactor operated for four test runs, including two pulses and two steady state runs. After each reactor run, the filters were counted using gamma spectrometry to identify the nuclides and to determine the activity of nuclides deposited on the filters. The study provided radionuclide release fraction data that can be used to estimate the airborne emissions resulting from APRF operations. The release fraction for particulate fission products and radioiodines, as derived from these measurements, was found to be 8.9 {times} 10{sup {minus}6} for reactor pulses and 4.3 {times} 10{sup {minus}6} for steady state operation. These values compare to a theoretical value of 1.5 {times} 10{sup {minus}5}.

  2. Radiation-driven hydrodynamics of long pulse hohlraums on the National Ignition Facility

    SciTech Connect

    Dewald, D L; Landen, O L; Suter, L J; Schein, J; Holder, J; Campbell, K; Glenzer, S H; McDonald, J W; Niemann, C; Mackinnon, A J; Schneider, M S; Haynam, C; Hinkel, D; Hammel, B A

    2005-10-17

    The first hohlraum experiments on the National Ignition Facility (NIF) using the first four laser beams have activated the indirect drive experimental capabilities and tested radiation temperature limits imposed by hohlraum plasma filling. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1 ns to 9 ns long square pulses and energies of up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Furthermore, for a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of plasma filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with analytical modeling that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits on full NIF (1.8 MJ) that are significantly greater than required for ignition hohlraums.

  3. PIN diode and neutron spectrum measurements at the Army Pulse Radiation Facility

    SciTech Connect

    Oliver, M.A.

    1994-12-01

    The Army Pulse Radiation Facility (APRF) is a multi-faceted facility operating a Godiva type pulse reactor, housed in a low scatter aluminum silo 30m in diameter and 20m high. The reactor is movable to several locations and heights. Several well characterized exposure environments are available for experiments. When testing silicon devices against a nuclear threat, it is essential to consider the difference between the neutron energy spectrum of the threat environment and that of the test environment. In this paper, neutron spectrum measurements using the foil activation technique have been made in two widely varying environments. One is an extremely high neutron-to-gamma field and the other extremely low. These measurements were used to characterize the fields and to evaluate the use of the DN-156 PIN diode for measuring 1 MeV equivalent neutron fluence in silicon ([Phi]1MeV(Si)). The agreement between the [Phi]1MeV(Si) as measured with diodes and as determined by the spectral measurements was within [+-] 5%. A proton recoil neutron spectrum measurement was also made in the low gamma environment.

  4. Final report of the gamma-ray leakage from the Aberdeen Pulse Radiation Facility (APRF) reactor. Final report

    SciTech Connect

    Heimbach, C.R.

    1995-04-01

    The gamma-ray leakage from the Aberdeen Pulse Radiation Facility (APRF) fast-burst reactor has been measured. A BGO spectrometer was used to measure spectrum, and a Geiger counter was used to measure dose. The two detectors were consistent, but measured about 60 percent more dose than indicated by calculation.

  5. Sources of pulsed radiation

    SciTech Connect

    Sauer, M.C. Jr.

    1981-01-01

    Characteristics of various sources of pulsed radiation are examined from the viewpoint of their importance to the radiation chemist, and some examples of uses of such sources are mentioned. A summary is given of the application of methods of physical dosimetry to pulsed sources, and the calibration of convenient chemical dosimeters by physical dosimetry is outlined. 7 figures, 1 table.

  6. Analysis of the Fall-1989 two-meter box test bed experiments performed at the Army Pulse Radiation Facility (APRF)

    NASA Astrophysics Data System (ADS)

    Johnson, J. O.; Drischler, J. D.; Barnes, J. M.

    This report summarizes the results of a benchmark analysis of the Monte Carlo Adjoint Shielding Code System (MASH) against a series of experiments performed at the Army Pulse Radiation Facility (APRF) in Aberdeen Proving Ground, Maryland. The series of experiments was performed in the Fall of 1989 and involved experimentalists from APRF; the Defense Research Establishment Ottawa, Canada (DREO); Bubble Technology Industries, Canada, (BTI); and the Establishment Technique Central de l'Armement, France (ETCA). The 'benchmark' analysis of MASH is designed to determine the capability of MASH to reproduce the measured neutron and gamma ray integral and differential (spectral) data. Results of the 'benchmark' analysis are to be used in the recommendations to the North Atlantic Treaty Organization (NATO) Panel 7 Ad Hoc Group of Shielding Experts for replacing the Vehicle Code System (VCS) with MASH as the reference code of choice for armored vehicle nuclear vulnerability calculations.

  7. SLAC pulsed x-ray facility

    SciTech Connect

    Ipe, N.E.; McCall, R.C.; Baker, E.D.

    1986-05-01

    The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the rf power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminium 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 ..mu..s. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The major part of the x-ray tube is enclosed in a large walk-in-cabinet made of 1.9 cm (3/4 in) plywood and lined with 0.32 cm (1/8 in) lead to make a very versatile facility. 3 refs., 5 figs.

  8. SLAC pulsed X-ray facility

    NASA Astrophysics Data System (ADS)

    Ipe, N. E.; McCall, R. C.; Baker, E. D.

    1986-05-01

    The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the RF power for the accelerator. Hence, a pulsed X-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The X-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminum 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 ms. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The major part of the X-ray tube is enclosed in a large walk-in-cabinet made of 1.9 cm (3/4 in) plywood and lined with 0.32 cm (1/8 in) lead to make a very versatile facility.

  9. Auditing radiation sterilization facilities

    NASA Astrophysics Data System (ADS)

    Beck, Jeffrey A.

    The diversity of radiation sterilization systems available today places renewed emphasis on the need for thorough Quality Assurance audits of these facilities. Evaluating compliance with Good Manufacturing Practices is an obvious requirement, but an effective audit must also evaluate installation and performance qualification programs (validation_, and process control and monitoring procedures in detail. The present paper describes general standards that radiation sterilization operations should meet in each of these key areas, and provides basic guidance for conducting QA audits of these facilities.

  10. The Brookhaven Radiation Effects Facility

    NASA Astrophysics Data System (ADS)

    Grand, P.; Snead, C. L.; Ward, T.

    The Neutral Particle Beam Radiation Effects Facility (REF), funded by the SDIO through the Defense Nuclear Agency and the Air Force Weapons Laboratory, has been constructed at Brookhaven National Laboratory. The operation started in October 1986. The REF is capable of delivering pulsed H(-), H(0), and H(+) beams of 100 to 200 MeV energy at up to 30 mA peak current. Pulses can be adjusted from 5-micron to 500-micron length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 sigma), resulting in a maximum dose of about 10 MRad (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives. This paper describes the REF, its capabilities and potential, and the experiments that have been carried out to date or are being planned.

  11. The Stanford Linear Accelerator Center pulsed x-ray facility.

    PubMed

    Ipe, N E; McCall, R C; Baker, E D

    1987-04-01

    The Stanford Linear Accelerator Center (SLAC) operates a high-energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the radio-frequency power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target window. The window consists of Al 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of Au 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 microseconds. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The maximum absorbed dose rate obtained at 6.35 cm below the target window as measured by an ionization chamber is 258 Gy/h. The major part of the x-ray tube is enclosed in a large walk-in cabinet made of 1.9-cm-thick (3/4-inch-thick) plywood and lined with 0.32-cm-thick (1/8-inch-thick) Pb to make a very versatile facility. PMID:3570789

  12. RADIATION FACILITY FOR NUCLEAR REACTORS

    DOEpatents

    Currier, E.L. Jr.; Nicklas, J.H.

    1961-12-12

    A radiation facility is designed for irradiating samples in close proximity to the core of a nuclear reactor. The facility comprises essentially a tubular member extending through the biological shield of the reactor and containing a manipulatable rod having the sample carrier at its inner end, the carrier being longitudinally movable from a position in close proximity to the reactor core to a position between the inner and outer faces of the shield. Shield plugs are provided within the tubular member to prevent direct radiation from the core emanating therethrough. In this device, samples may be inserted or removed during normal operation of the reactor without exposing personnel to direct radiation from the reactor core. A storage chamber is also provided within the radiation facility to contain an irradiated sample during the period of time required to reduce the radioactivity enough to permit removal of the sample for external handling. (AEC)

  13. Electromagnetic Pulses at Short-Pulse Laser Facilities

    SciTech Connect

    Brown, Jr., C G; Throop, A; Eder, D; Kimbrough, J

    2007-08-28

    Electromagnetic Pulse (EMP) is a known issue for short-pulse laser facilities, and will also be an issue for experiments using the advanced radiographic capability (ARC) at the National Ignition Facility (NIF). The ARC diagnostic uses four NIF beams that are compressed to picosecond durations for backlighting ignition capsules and other applications. Consequently, we are working to understand the EMP due to high-energy (MeV) electrons escaping from targets heated by short-pulse lasers. Our approach is to measure EMP in the Titan short-pulse laser at Lawrence Livermore National Laboratory (LLNL) and to employ that data to establish analysis and simulation capabilities. We have installed a wide variety of probes inside and outside the Titan laser chamber. We have high-frequency B-dots and D-dots, a photodiode, and fast current-viewing and integrating current transformers. The probe outputs are digitized by 10 and 20 Gsample/s oscilloscopes. The cables and oscilloscopes are well shielded to reduce noise. Our initial measurement campaign has yielded data useful mainly from hundreds of MHz to several GHz. We currently are supplementing our high-frequency probes with lower-frequency ones to obtain better low-frequency data. In order to establish analysis and simulation capabilities we are modeling the Titan facility using various commercial and LLNL numerical electromagnetic codes. We have simulated EMP generation by having a specified number of electrons leave the target and strike the chamber wall and other components in the chamber. This short impulse of electrons has a corresponding broad spectrum, exciting high-frequency structure in the resulting EMP. In this paper, we present results of our initial measurement campaign and comparisons between the measurements and simulations.

  14. Electromagnetic Pulses at Short-Pulse Laser Facilities

    SciTech Connect

    Brown, C G; Throop, A; Eder, D; Kimbrough, J

    2008-02-04

    Electromagnetic Pulse (EMP) is a known issue for short-pulse laser facilities, and will also be an issue for experiments using the advanced radiographic capability (ARC) at the National Ignition Facility (NIF). The ARC diagnostic uses four NIF beams that are compressed to picosecond durations for backlighting ignition capsules and other applications. Consequently, we are working to understand the EMP due to high-energy (MeV) electrons escaping from targets heated by short-pulse lasers. Our approach is to measure EMP in the Titan short-pulse laser at Lawrence Livermore National Laboratory (LLNL) and to employ that data to establish analysis and simulation capabilities. We have installed a wide variety of probes inside and outside the Titan laser chamber. We have high-frequency B-dot and D-dot probes, a photodiode, and fast current-viewing and integrating current transformers. The probe outputs are digitized by 10 and 20 Gsample/s oscilloscopes. The cables and oscilloscopes are well shielded to reduce noise. Our initial measurement campaign has yielded data useful mainly from several hundreds of MHz to several GHz. We currently are supplementing our high-frequency probes with lower-frequency ones to obtain better low-frequency data. In order to establish analysis and simulation capabilities we are modeling the Titan facility using various commercial and LLNL numerical electromagnetics codes. We have simulated EMP generation by having a specified number of electrons leave the target and strike the chamber wall and other components in the chamber. This short impulse of electrons has a correspondingly broad spectrum, exciting high-frequency structure in the resulting EMP. In this paper, we present results of our initial measurement campaign and comparisons between the measurements and simulations.

  15. Vacuum photoelectronic devices for measuring pulsed radiation

    NASA Astrophysics Data System (ADS)

    Berkovskii, A. G.; Veretennikov, A. I.; Kozlov, O. V.

    The design of these devices is discussed, and data are presented on their characteristics. These vacuum photoelectronic devices comprise photocells, photomultipliers, and electrooptical transducers designed for measuring pulsed radiation of nanosecond and subnanosecond duration. The fluctuation characteristics of the devices are examined, and their use in detectors of pulsed luminous and ionizing radiation is considered.

  16. Accelerator Facilities for Radiation Research

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    1999-01-01

    HSRP Goals in Accelerator Use and Development are: 1.Need for ground-based heavy ion and proton facility to understand space radiation effects discussed most recently by NAS/NRC Report (1996). 2. Strategic Program Goals in facility usage and development: -(1) operation of AGS for approximately 600 beam hours/year; (2) operation of Loma Linda University (LLU) proton facility for approximately 400 beam hours/year; (3) construction of BAF facility; and (4) collaborative research at HIMAC in Japan and with other existing or potential international facilities. 3. MOA with LLU has been established to provide proton beams with energies of 40-250 important for trapped protons and solar proton events. 4. Limited number of beam hours available at Brookhaven National Laboratory's (BNL) Alternating Gradient Synchrotron (AGS).

  17. High-power ultrawideband electromagnetic pulse radiation

    NASA Astrophysics Data System (ADS)

    Koshelev, Vladimir I.; Buyanov, Yuri I.; Koval'chuk, Boris M.; Andreev, Yuri A.; Belichenko, Victor P.; Efremov, Anatoly M.; Plisko, Vyacheslav V.; Sukhushin, Konstantin N.; Vizir, Vadim A.; Zorin, Valery B.

    1997-10-01

    Basing on energetic processes studying in the near-field radiator zone, a new concept of antenna synthesizing for ultrawideband electromagnetic pulse radiation has been suggested. The results of experimental investigations of the antennae developed with using of this concept for high-power applications are presented. The antennae have small dimensions, high electrical strength, cardioid pattern with linear polarization of the pulse radiated and they are ideally adapted to be used as a steering antenna array element. A high-voltage nanosecond bipolar pulse generator design to excite antennae is described.

  18. Radiation Facilities for Composite Materials Formation

    NASA Astrophysics Data System (ADS)

    Popov, G. F.; Zalubovsky, I. I.; Avilov, A. M.; Rudychev, V. G.

    1997-05-01

    The radiation facilities on the base of linac for polymer composite materials (PCM) formation was designed. The general technological scheme of PCM production consists in impregnations by synthetic monomers or oligomers of wares made of capillaryporous materials such as wood, qypsum, concrete, ceramic, paper, waste of papermaking, textile and woodworking production which are further treated by relativistic electron or breamsstruhglung beams. The facilities encorporates a linac with scanning electron beams, microwave chamber for drying of materials, a system for vacuum impregnating of materials with synthetic origomers, test bench for irradiations of samples, precise monitoring system for measuring of three-dimentional dose distribution in irradiated samples, and control processing system. The main beam parameters of linac are: electron energy 5--8 MeV; mean beam power up to 5 kW, pulse duration 1--4 mcs; scanning frequency of electromagnetic scanner 1--8 Hz; the irradiation is possible both with electron and with breamsstrahglung beams. The facilities were used for radiation processing investigation and production of new high-strength and corrosian-resistant PCM.

  19. Survivable pulse power space radiator

    DOEpatents

    Mims, James; Buden, David; Williams, Kenneth

    1989-01-01

    A thermal radiator system is described for use on an outer space vehicle, which must survive a long period of nonuse and then radiate large amounts of heat for a limited period of time. The radiator includes groups of radiator panels that are pivotally connected in tandem, so that they can be moved to deployed configuration wherein the panels lie largely coplanar, and to a stowed configuration wherein the panels lie in a stack to resist micrometeorite damage. The panels are mounted on a boom which separates a hot power source from a payload. While the panels are stowed, warm fluid passes through their arteries to keep them warm enough to maintain the coolant in a liquid state and avoid embrittlement of material. The panels can be stored in a largely cylindrical shell, with panels progressively further from the boom being of progressively shorter length.

  20. Survivable pulse power space radiator

    DOEpatents

    Mims, J.; Buden, D.; Williams, K.

    1988-03-11

    A thermal radiator system is described for use on an outer space vehicle, which must survive a long period of nonuse and then radiate large amounts of heat for a limited period of time. The radiator includes groups of radiator panels that are pivotally connected in tandem, so that they can be moved to deployed configuration wherein the panels lie largely coplanar, and to a stowed configuration wherein the panels lie in a stack to resist micrometerorite damage. The panels are mounted on a boom which separates a hot power source from a payload. While the panels are stowed, warm fluid passes through their arteries to keep them warm enough to maintain the coolant in a liquid state and avoid embrittlement of material. The panels can be stored in a largely cylindrical shell, with panels progressively further from the boom being of progressively shorter length. 5 figs.

  1. Electron trajectories in pulsed radiation fields

    SciTech Connect

    Einwohner, T.; Lippmann, B.A.

    1987-05-01

    The work reported here analyzes the dynamical behavior of an electron, initially at rest, when subjected to a radiation pulse of arbitrary, but integrable, shape. This is done by a general integration procedure that has been programmed in VAXIMA. Upon choosing a specific shape for the pulse, VAXIMA finds both the space-time trajectory and the four-momentum of the electron. These are obtained in analytic or numerical form - or both - at the choice of the user. Several examples of analytical and numerical solutions, for different pulse shapes, are given.

  2. Background radiation from fission pulses

    SciTech Connect

    England, T.R.; Arthur, E.D.; Brady, M.C.; LaBauve, R.J.

    1988-05-01

    Extensive source terms for beta, gamma, and neutrons following fission pulses are presented in various tabular and graphical forms. Neutron results from a wide range of fissioning nuclides (42) are examined and detailed information is provided for four fuels: /sup 235/U, /sup 238/U, /sup 232/Th, and /sup 239/Pu; these bracket the range of the delayed spectra. Results at several cooling (decay) times are presented. For ..beta../sup -/ and ..gamma.. spectra, only /sup 235/U and /sup 239/Pu results are given; fission-product data are currently inadequate for other fuels. The data base consists of all known measured data for individual fission products extensively supplemented with nuclear model results. The process is evolutionary, and therefore, the current base is summarized in sufficient detail for users to judge its quality. Comparisons with recent delayed neutron experiments and total ..beta../sup -/ and ..gamma.. decay energies are included. 27 refs., 47 figs., 9 tabs.

  3. Radiated fields from an electromagnetic pulse simulator

    NASA Astrophysics Data System (ADS)

    Pelletier, M.; Delisle, G. Y.; Kashyap, S.

    Simulators of electromagnetic pulses allow generation within a limited time of very high-intensity fields such as those produced in a nuclear explosion. These fields can be radiated out of the test zone at a lower but nevertheless significant level; if the intensity of these fields is sufficiently high, damage to humans and electronic equipment can result. An evaluation of the potential danger of these simulator emissions requires knowledge of the amplitude, duration, and the energy of the radiated impulses. A technique is presented for calculating the fields radiated by a parallel-plane electromagnetic pulse simulator. The same method can also be applied to a rhombic type simulator. Sample numerical results are presented along with the calculations of the energy and power density and a discussion of the formation of the field in the frequency domain.

  4. Intense terahertz pulses from SPARC_LAB coherent radiation source

    NASA Astrophysics Data System (ADS)

    Giorgianni, F.; Bellaveglia, M.; Castellano, M.; Chiadroni, E.; Cianchi, A.; Daniele, M.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Lupi, S.; Mostacci, A.; Petrarca, M.; Pompili, R.; Shpakov, V.; Villa, F.

    2015-05-01

    The linac-based Terahertz source at the SPARC_LAB test facility is able to generate highly intense Terahertz broadband pulses via coherent transition radiation (CTR) from high brightness electron beams. The THz pulse duration is typically down to 100 fs RMS and can be tuned through the electron bunch duration and shaping. The measured stored energy in a single THz pulse has reached 40 μJ, which corresponds to a peak electric field of 1.6 MV/cm at the THz focus. Here we present the main features, in particular spatial and spectral distributions and energy characterizations of the SPARC_LAB THz source, which is very competitive for investigations in Condensed Matter, as well as a valid tool for electron beam longitudinal diagnostics.

  5. Radiation Safety Systems for Accelerator Facilities

    SciTech Connect

    Liu, James C

    2001-10-17

    The Radiation Safety System (RSS) of an accelerator facility is used to protect people from prompt radiation hazards associated with accelerator operation. The RSS is a fully interlocked, engineered system with a combination of passive and active elements that are reliable, redundant, and fail-safe. The RSS consists of the Access Control System (ACS) and the Radiation Containment System (RCS). The ACS is to keep people away from the dangerous radiation inside the shielding enclosure. The RCS limits and contains the beam/radiation conditions to protect people from the prompt radiation hazards outside the shielding enclosure in both normal and abnormal operations. The complexity of a RSS depends on the accelerator and its operation, as well as associated hazard conditions. The approaches of RSS among different facilities can be different. This report gives a review of the RSS for accelerator facilities.

  6. Radiation Safety Systems for Accelerator Facilities

    SciTech Connect

    James C. Liu; Jeffrey S. Bull; John Drozdoff; Robert May; Vaclav Vylet

    2001-10-01

    The Radiation Safety System (RSS) of an accelerator facility is used to protect people from prompt radiation hazards associated with accelerator operation. The RSS is a fully interlocked, engineered system with a combination of passive and active elements that are reliable, redundant, and fail-safe. The RSS consists of the Access Control System (ACS) and the Radiation Containment System (RCS). The ACS is to keep people away from the dangerous radiation inside the shielding enclosure. The RCS limits and contains the beam/radiation conditions to protect people from the prompt radiation hazards outside the shielding enclosure in both normal and abnormal operations. The complexity of a RSS depends on the accelerator and its operation, as well as associated hazard conditions. The approaches of RSS among different facilities can be different. This report gives a review of the RSS for accelerator facilities.

  7. Recent re-measurement of neutron and gamma-ray spectra 1080 meters from the APRD (Army Pulse Radiation Division) critical facility

    NASA Astrophysics Data System (ADS)

    Robitaille, H. A.; Hoffarth, B. E.

    1984-01-01

    Previously reported measurements of long-range air-transported neutron and gamma-ray spectra from the fast-critical facility at the US Army Aberdeen Proving Ground have been supplemented recently at the 1080-meter position. The results of these determinations are presented herein and compared to several recent calculations from other research establishments. In addition, a summary of all dosimetric measurements obtained in the period 1979-1982 are appended, as are new determinations of APRD soil composition. Integral quantities such as neutron and gamma-ray kermas are very well predicted by the latest calculations, however there still exist significant spectral differences. At short ranges calculated neutron spectra are somewhat softer than experimental measurements, but at the farthest range of 1080 meters agreement is surprisingly good. Gamma-ray spectra remain well-calculated at all ranges.

  8. Numerical Simulations of High Enthalpy Pulse Facilities

    NASA Technical Reports Server (NTRS)

    Wilson, Gregory J.; Edwards, Thomas A. (Technical Monitor)

    1995-01-01

    Axisymmetric flows within shock tubes and expansion tubes are simulated including the effects of finite rate chemistry and both laminar and turbulent boundary layers. The simulations demonstrate the usefulness of computational fluid dynamics for characterizing the flows in high enthalpy pulse facilities. The modeling and numerical requirements necessary to simulate these flows accurately are also discussed. Although there is a large body of analysis which explains and quantifies the boundary layer growth between the shock and the interface in a shock tube, there is a need for more detailed solutions. Phenomena such as thermochemical nonequilibrium. or turbulent transition behind the shock are excluded in the assumptions of Mirels' analysis. Additionally there is inadequate capability to predict the influence of the boundary layer on the expanded gas behind the interface. Quantifying the gas in this region is particularly important in expansion tubes because it is the location of the test gas. Unsteady simulations of the viscous flow in shock tubes are computationally expensive because they must follow features such as a shock wave over the length of the facility and simultaneously resolve the small length scales within the boundary layer. As a result, efficient numerical algorithms are required. The numerical approach of the present work is to solve the axisymmetric gas dynamic equations using an finite-volume formulation where the inviscid fluxes are computed with a upwind TVD scheme. Multiple species equations are included in the formulation so that finite-rate chemistry can be modeled. The simulations cluster grid points at the shock and interface and translate this clustered grid with these features to minimize numerical errors. The solutions are advanced at a CFL number of less than one based on the inviscid gas dynamics. To avoid limitations on the time step due to the viscous terms, these terms are treated implicitly. This requires a block tri

  9. Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

    SciTech Connect

    Brown, Jr., C G; Bond, E; Clancy, T; Dangi, S; Eder, D C; Ferguson, W; Kimbrough, J; Throop, A

    2010-02-04

    The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.

  10. Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

    SciTech Connect

    Brown, Jr., C G; Bond, E; Clancy, T; Dangi, S; Eder, D C; Ferguson, W; Kimbrough, J; Throop, A

    2009-10-02

    The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.

  11. Generating Microwave Radiation Pulses with MCG

    NASA Astrophysics Data System (ADS)

    Zherlitsyn, A. G.; Kanaev, G. G.; Melnikov, G. V.; Tsvetkov, V. I.; Ushnurtsev, A. E.; Dudin, S. V.; Mintsev, V. B.; Fortov, V. E.

    2004-11-01

    Transformer schemes matching magnetocumulative generators (MCG) with high impedance loads, like vircator, look promising for achieving long pulse duration of 1 μs. An analysis of expected parameters is made here. The necessary MCG and transformer parameters are discussed and the experimental set-up is described. The shots with the MCG simulator were carried out first. At simulator voltage 40 kV and reserved energy 12 kJ, the voltage pulse with amplitude to 600 kV and 320 ns duration is generated on a triode with a virtual cathode. Microwave radiation of 300-400 MW and 200-300 ns duration is generated within a 10 cm wavelength range.

  12. Radiation safety at accelerator facilities NCRP activities

    NASA Astrophysics Data System (ADS)

    Kase, Kenneth R.

    1997-02-01

    The National Council on Radiation Protection and Measurements (NCRP) has issued 13 reports, dating back to 1949, giving guidance and recommendations for radiation protection at accelerator facilities. There are six current reports on the topics of neutron radiation; facility and shielding design; alarms and access control systems; and equipment design, performance, and use. Scientific Committee 46 (SC 46) is currently overseeing the development of two reports that will provide up-to-date guidance for the design of medical accelerator facilities and shielding. SC 46 has also proposed that a report be written to provide guidance for the design and shielding of industrial accelerator and large irradiator facilities. This paper describes the status and contents of these reports.

  13. Architecture and operation of the Z Pulsed Power Facility vacuum system.

    SciTech Connect

    Riddle, Allen Chauncey; Petmecky, Don; Weed, John Woodruff

    2010-11-01

    The Z Pulsed Power Facility at Sandia National Laboratories in Albuquerque, New Mexico, USA is one of the world's premier high energy density physics facilities. The Z Facility derives its name from the z-pinch phenomena which is a type of plasma confinement system that uses the electrical current in the plasma to generate a magnetic field that compresses it. Z refers to the direction of current flow, the z axis in a three dimensional Cartesian coordinate system. The multiterawatt, multimegajoule electrical pulse the Facility produces is 100-400 nanoseconds in time. Research and development programs currently being conducted on the Z Facility include inertial confinement fusion, dynamic material properties, laboratory astrophysics and radiation effects. The Z Facility vacuum system consists of two subsystems, center section and load diagnostics. Dry roughing pumps and cryogenic high vacuum pumps are used to evacuate the 40,000 liter, 200 square meter center section of the facility where the experimental load is located. Pumping times on the order of two hours are required to reduce the pressure from atmospheric to 10{sup -5} Torr. The center section is cycled from atmosphere to high vacuum for each experiment. The facility is capable of conducting one to two experiments per day. Numerous smaller vacuum pumping systems are used to evacuate load diagnostics. The megajoules of energy released during an experiment causes damage to the Facility that presents numerous challenges for reliable operation of the vacuum system.

  14. MBI facility at BESSY II for time-resolved pump-probe techniques with laser and undulator radiation

    NASA Astrophysics Data System (ADS)

    Gatzke, Johannes; Winter, Bernd J.; Quast, T.; Hertel, Ingolf V.

    1998-10-01

    The MBI develops a facility at BESSY II dedicated to pump- probe techniques combining synchrotron and laser radiation. The synchronization of laser and synchrotron pulses will allow time resolved experiments on the picosecond time scale at this. The features of the facility, the optical parameters of the synchrotron beamline, the synchronization technique and pulse stretching considerations will be outlined. Current developments will be reported.

  15. Laboratory Astrophysics on High Power Lasers and Pulsed Power Facilities

    SciTech Connect

    Remington, B A

    2002-02-05

    Over the past decade a new genre of laboratory astrophysics has emerged, made possible by the new high energy density (HED) experimental facilities, such as large lasers, z-pinch generators, and high current particle accelerators. (Remington, 1999; 2000; Drake, 1998; Takabe, 2001) On these facilities, macroscopic collections of matter can be created in astrophysically relevant conditions, and its collective properties measured. Examples of processes and issues that can be experimentally addressed include compressible hydrodynamic mixing, strong shock phenomena, radiative shocks, radiation flow, high Mach-number jets, complex opacities, photoionized plasmas, equations of state of highly compressed matter, and relativistic plasmas. These processes are relevant to a wide range of astrophysical phenomena, such as supernovae and supernova remnants, astrophysical jets, radiatively driven molecular clouds, accreting black holes, planetary interiors, and gamma-ray bursts. These phenomena will be discussed in the context of laboratory astrophysics experiments possible on existing and future HED facilities.

  16. Long-pulse magnetic field facility at Zaragoza

    NASA Astrophysics Data System (ADS)

    Algarabel, P. A.; del Moral, A.; Martín, C.; Serrate, D.; Tokarz, W.

    2006-11-01

    The long-pulse magnetic field facility of the Laboratorio de Magnetismo - Instituto de Ciencia de Materiales de Aragón (Universidad de Zaragoza-CSIC) produces magnetic fields up to 31, with a pulse duration of 2.2s. Experimental set-ups for measurements of magnetization, magnetostriction and magnetoresistance are available. The temperature can be controlled between 1.4 and 335 K, being the inner bore of the He cryostat of 22.5 mm. Magnetization is measured using the mutual induction technique, the magnetostriction is determined with the strain-gage and the capacitive cantilever methods, and the magnetoresistance is measured by means of the aclock-in technique in the 4-probes geometry. An overview of the facility will be presented and the presently available experimental techniques will be discussed.

  17. Establishing a NORM based radiation calibration facility.

    PubMed

    Wallace, J

    2016-05-01

    An environmental radiation calibration facility has been constructed by the Radiation and Nuclear Sciences unit of Queensland Health at the Forensic and Scientific Services Coopers Plains campus in Brisbane. This facility consists of five low density concrete pads, spiked with a NORM source, to simulate soil and effectively provide a number of semi-infinite uniformly distributed sources for improved energy response calibrations of radiation equipment used in NORM measurements. The pads have been sealed with an environmental epoxy compound to restrict radon loss and so enhance the quality of secular equilibrium achieved. Monte Carlo models (MCNP),used to establish suitable design parameters and identify appropriate geometric correction factors linking the air kerma measured above these calibration pads to that predicted for an infinite plane using adjusted ICRU53 data, are discussed. Use of these correction factors as well as adjustments for cosmic radiation and the impact of surrounding low levels of NORM in the soil, allows for good agreement between the radiation fields predicted and measured above the pads at both 0.15 m and 1 m. PMID:26921707

  18. Dual amplitude pulse generator for radiation detectors

    DOEpatents

    Hoggan, Jerry M.; Kynaston, Ronnie L.; Johnson, Larry O.

    2001-01-01

    A pulsing circuit for producing an output signal having a high amplitude pulse and a low amplitude pulse may comprise a current source for providing a high current signal and a low current signal. A gate circuit connected to the current source includes a trigger signal input that is responsive to a first trigger signal and a second trigger signal. The first trigger signal causes the gate circuit to connect the high current signal to a pulse output terminal whereas the second trigger signal causes the gate circuit to connect the low current signal to the pulse output terminal.

  19. Pulse generation and preamplification for long pulse beamlines of Orion laser facility.

    PubMed

    Hillier, David I; Winter, David N; Hopps, Nicholas W

    2010-06-01

    We describe the pulse generation, shaping, and preamplification system for the nanosecond beamlines of the Orion laser facility. The system generates shaped laser pulses of up to approximately 1 J of 100 ps-5 ns duration with a programmable temporal profile. The laser has a 30th-power supergaussian spatial profile and is diffraction limited. The system is capable of imposing 2D smoothing by spectral dispersion upon the beam, which will produce a nonuniformity of 10% rms at the target. PMID:20517369

  20. Revisit on dynamic radiation forces induced by pulsed Gaussian beams.

    PubMed

    Wang, Li-Gang; Chai, Hai-Shui

    2011-07-18

    Motivated by the recent optical trapping experiments using ultra-short pulsed lasers [Opt. Express 18, 7554 (2010); Appl. Opt. 48, G33 (2009)], in this paper we have re-investigated the trapping effects of the pulsed radiation force (PRF), which is induced by a pulsed Gaussian beam acting on a Rayleigh dielectric sphere. Based on our previous model [Opt. Express 15, 10615 (2007)], we have considered the effects arisen from both the transverse and axial PRFs, which lead to the different behaviors of both velocities and displacements of a Rayleigh particle within a pulse duration. Our analysis shows that, for the small-sized Rayleigh particles, when the pulse has the large pulse duration, it might provide the three-dimensional optical trapping; and when the pulse has the short pulse duration, it only provides the two-dimensional optical trapping with the axial movement along the pulse propagation. When the particle is in the vacuum or in the situation with the very weak Brownian motion, the particle can always be trapped stably due to the particle's cumulative momentum transferred from the pulse, and only in this case the trapping effect is independent of pulse duration. Finally, we have predicted that for the large-sized Rayleigh particles, the pulse beam can only provide the two-dimensional optical trap (optical guiding). Our results provide the important information about the trapping mechanism of pulsed tweezers. PMID:21934801

  1. Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation

    PubMed Central

    Eilenberger, Falk; Kabakova, Irina V.; de Sterke, C. Martijn; Eggleton, Benjamin J.; Pertsch, Thomas

    2013-01-01

    We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations. PMID:24060831

  2. Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility

    DOE PAGESBeta

    Grills, David C.; Farrington, Jaime A.; Layne, Bobby H.; Preses, Jack M.; Bernstein, Herbert J.; Wishart, James F.

    2015-04-27

    When coupled with transient absorption spectroscopy, pulse radiolysis, which utilizes high-energy electron pulses from an accelerator, is a powerful tool for investigating the kinetics and thermodynamics of a wide range of radiation-induced redox and electron transfer processes. The majority of these investigations detect transient species in the UV, visible, or near-IR spectral regions. Unfortunately, the often-broad and featureless absorption bands in these regions can make the definitive identification of intermediates difficult. Time-resolved vibrational spectroscopy would offer much improved structural characterization, but has received only limited application in pulse radiolysis. In this paper, we describe in detail the development of amore » unique nanosecond time-resolved infrared (TRIR) detection capability for condensed-phase pulse radiolysis on a new beam line at the LEAF facility of Brookhaven National Laboratory. The system makes use of a suite of high-power, continuous wave external-cavity quantum cascade lasers as the IR probe source, with coverage from 2330-1051 cm⁻¹. The response time of the TRIR detection setup is ~40 ns, with a typical sensitivity of ~100 µOD after 4-8 signal averages using a dual-beam probe/reference normalization detection scheme. As a result, this new detection method has enabled mechanistic investigations of a range of radiation-induced chemical processes, some of which are highlighted here.« less

  3. Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility

    SciTech Connect

    Grills, David C.; Farrington, Jaime A.; Layne, Bobby H.; Preses, Jack M.; Bernstein, Herbert J.; Wishart, James F.

    2015-04-27

    When coupled with transient absorption spectroscopy, pulse radiolysis, which utilizes high-energy electron pulses from an accelerator, is a powerful tool for investigating the kinetics and thermodynamics of a wide range of radiation-induced redox and electron transfer processes. The majority of these investigations detect transient species in the UV, visible, or near-IR spectral regions. Unfortunately, the often-broad and featureless absorption bands in these regions can make the definitive identification of intermediates difficult. Time-resolved vibrational spectroscopy would offer much improved structural characterization, but has received only limited application in pulse radiolysis. In this paper, we describe in detail the development of a unique nanosecond time-resolved infrared (TRIR) detection capability for condensed-phase pulse radiolysis on a new beam line at the LEAF facility of Brookhaven National Laboratory. The system makes use of a suite of high-power, continuous wave external-cavity quantum cascade lasers as the IR probe source, with coverage from 2330-1051 cm⁻¹. The response time of the TRIR detection setup is ~40 ns, with a typical sensitivity of ~100 µOD after 4-8 signal averages using a dual-beam probe/reference normalization detection scheme. As a result, this new detection method has enabled mechanistic investigations of a range of radiation-induced chemical processes, some of which are highlighted here.

  4. Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility

    SciTech Connect

    Grills, David C. Farrington, Jaime A.; Layne, Bobby H.; Preses, Jack M.; Wishart, James F.; Bernstein, Herbert J.

    2015-04-15

    When coupled with transient absorption spectroscopy, pulse radiolysis, which utilizes high-energy electron pulses from an accelerator, is a powerful tool for investigating the kinetics and thermodynamics of a wide range of radiation-induced redox and electron transfer processes. The majority of these investigations detect transient species in the UV, visible, or near-IR spectral regions. Unfortunately, the often-broad and featureless absorption bands in these regions can make the definitive identification of intermediates difficult. Time-resolved vibrational spectroscopy would offer much improved structural characterization, but has received only limited application in pulse radiolysis. In this paper, we describe in detail the development of a unique nanosecond time-resolved infrared (TRIR) detection capability for condensed-phase pulse radiolysis on a new beam line at the LEAF facility of Brookhaven National Laboratory. The system makes use of a suite of high-power, continuous wave external-cavity quantum cascade lasers as the IR probe source, with coverage from 2330 to 1051 cm{sup −1}. The response time of the TRIR detection setup is ∼40 ns, with a typical sensitivity of ∼100 μOD after 4-8 signal averages using a dual-beam probe/reference normalization detection scheme. This new detection method has enabled mechanistic investigations of a range of radiation-induced chemical processes, some of which are highlighted here.

  5. Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility

    NASA Astrophysics Data System (ADS)

    Grills, David C.; Farrington, Jaime A.; Layne, Bobby H.; Preses, Jack M.; Bernstein, Herbert J.; Wishart, James F.

    2015-04-01

    When coupled with transient absorption spectroscopy, pulse radiolysis, which utilizes high-energy electron pulses from an accelerator, is a powerful tool for investigating the kinetics and thermodynamics of a wide range of radiation-induced redox and electron transfer processes. The majority of these investigations detect transient species in the UV, visible, or near-IR spectral regions. Unfortunately, the often-broad and featureless absorption bands in these regions can make the definitive identification of intermediates difficult. Time-resolved vibrational spectroscopy would offer much improved structural characterization, but has received only limited application in pulse radiolysis. In this paper, we describe in detail the development of a unique nanosecond time-resolved infrared (TRIR) detection capability for condensed-phase pulse radiolysis on a new beam line at the LEAF facility of Brookhaven National Laboratory. The system makes use of a suite of high-power, continuous wave external-cavity quantum cascade lasers as the IR probe source, with coverage from 2330 to 1051 cm-1. The response time of the TRIR detection setup is ˜40 ns, with a typical sensitivity of ˜100 μOD after 4-8 signal averages using a dual-beam probe/reference normalization detection scheme. This new detection method has enabled mechanistic investigations of a range of radiation-induced chemical processes, some of which are highlighted here.

  6. Radiation and propagation of short acoustical pulses from underground explosions

    SciTech Connect

    Banister, J.R.

    1982-06-01

    Radiation and propagation of short acoustical pulses from underground nuclear explosions were analyzed. The cone of more intense radiation is defined by the ratio of sound speeds in the ground and air. The pressure history of the radiated pulse is a function of the vertical ground-motion history, the range, the burial depth, and the velocity of longitudinal seismic waves. The analysis of short-pulse propagation employed an N-wave model with and without enegy conservation. Short pulses with initial wave lengths less than 100 m are severely attenuated by the energy loss in shocks and viscous losses in the wave interior. The methods developed in this study should be useful for system analysis.

  7. Energy Characteristics of Radiators of Ultrashort Electromagnetic Pulses

    NASA Astrophysics Data System (ADS)

    Usychenko, V. G.; Usychenko, A. S.; Sorokin, L. N.

    2015-07-01

    It is shown that to use the maximum share of the energy of a unipolar ultrashort electric pulse, its duration and shape, as well as the transmitting antenna parameters should, be related to the receiver center frequency and passband in a certain manner. Distortions introduced by the propagation effects to the received-radiation spectrum shape increase with broadening radiation and receiver frequency bands.

  8. Ejecta experiments at the Pegasus Pulsed Power facility

    SciTech Connect

    Sorenson, D.S.; Carpenter, B.; King, N.S.P.

    1997-08-01

    When a shock wave interacts at the surface of a metal target, target material can be emitted from the surface called ejecta. The mass, size, shape, and velocity of ejecta varies depending on the initial shock conditions, and target material properties. In order to understand this phenomena, diagnostics have been developed and implemented at the Pegasus Pulsed Power facility located at Los Alamos National Laboratory. The facility provides both radial and axial access for making measurements. There exist optical, laser, and x-ray paths for performing measurements on the target assembly located near the center of the machine. The facility can provide many mega amps of current which is transported to a 5.0 cm diameter, 2.0 cm high aluminum cylinder. The current and associated magnetic field set up forces which implode the aluminum cylinder radially inward. As the aluminum cylinder reaches the appropriate velocity it impacts a target cylinder. Due to this impact, a shock wave is set up in the target and eventually interacts at the inner surface of the target cylinder where ejecta are produced. A 1.5 cm diameter collimator cylinder located inside the target cylinder is used to control the number of ejecta particles that arrive at the center region where ejecta measurements are made. Diagnostics have been developed including in-line Fraunhofer holography and visible shadowgraph. Details of these diagnostics are described.

  9. Transportation of an electromagnetic pulse to the load in the Angara-5-1 facility

    SciTech Connect

    Aleksandrov, V. V.; Grabovski, E. V.; Gribov, A. N.; Oleinik, G. M.; Samokhin, A. A.; Sasorov, P. V.

    2008-11-15

    One of the main problems in Z-pinch experiments is to transport power and energy from the generator to the load. As the pulse produced in a double forming line propagates to the load along a water-vacuum insulator, its power and energy decrease due to current leakage in the plasma shortening the gap and during the establishment of magnetic self-insulation in regions with a zero magnetic field. Only a fraction of the delivered energy is spent on the load implosion, whereas the rest of the energy goes on creating the magnetic field around the load. In this work, an analysis is made of what is the fraction of the generator energy that reaches the liner, what fraction is radiated, and what are losses of energy and current in different stages of transporting the electromagnetic pulse to the load of the Angara-5-1 facility.

  10. Scramjet mixing establishment times for a pulse facility

    NASA Technical Reports Server (NTRS)

    Rogers, R. Clayton; Weidner, Elizabeth H.

    1991-01-01

    A numerical simulation of the temporally developing flow through a generic scramjet combustor duct is presented for stagnation conditions typical of flight at Mach 13 as produced by a shock tunnel pulse facility. The particular focus is to examine the start up transients and to determine the time required for certain flow parameters to become established. The calculations were made with a Navier-Stokes solver SPARK with temporally relaxing inflow conditions derived from operation of the T4 shock tunnel at the University of Queensland in Australia. Calculations at nominal steady inflow conditions were made for comparison. The generic combustor geometry includes the injection of hydrogen fuel from the base of a centrally located strut. In both cases, the flow was assumed laminar and fuel combustion was not included. The establishment process is presented for viscous parameters in the boundary layer and for parameters related to the fuel mixing.

  11. The Short-Pulse X-ray Facility at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Young, Linda; Evans, Paul

    2013-05-01

    The Short-Pulse X-ray (SPX) Facility will extend time-resolved x-ray scattering and spectroscopy to the picosecond time scale while retaining the powerful characteristics of synchrotron radiation, i.e., user-controlled continuous tunability of energy, polarization, and bandwidth combined with exquisite x-ray energy and pulse-length stability over a wide energy range. Experiments at the SPX facility will produce 1-ps stroboscopic snapshots of molecular rotations, molecular excited-state transient structures, stress/strain wave propagation, magnetic domain wall dynamics, phase transitions, and the coupling between electronic, vibrational, and magnetic degrees of freedom in condensed matter systems. Time-resolved studies of transient dynamics will be possible with simultaneous picosecond time resolution and picometer structural precision for a variety of atomic, molecular, supramolecular, nanoscale, and bulk material systems. Pump-probe experiments using high-average-power, sub-picosecond, high-repetition-rate laser systems will make efficient use of the MHz x-ray rates of the SPX. Five end stations for x-ray scattering, diffraction, spectroscopy, imaging, and microscopy can be developed as part of the Advanced Photon Source Upgrade project. The Advanced Photon Source is an Office of Science User Facility operated for the U.S. Dept of Energy Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357.

  12. Assessment and Mitigation of Radiation, EMP, Debris & Shrapnel Impacts at Megajoule-Class Laser Facilities

    SciTech Connect

    Eder, D C; Anderson, R W; Bailey, D S; Bell, P; Benson, D J; Bertozzi, A L; Bittle, W; Bradley, D; Brown, C G; Clancy, T J; Chen, H; Chevalier, J M; Combis, P; Dauffy, L; Debonnel, C S; Eckart, M J; Fisher, A C; Geille, A; Glebov, V Y; Holder, J; Jadaud, J P; Jones, O; Kaiser, T B; Kalantar, D; Khater, H; Kimbrough, J; Koniges, A E; Landen, O L; MacGowan, B J; Masters, N D; MacPhee, A; Maddox, B R; Meyers, M; Osher, S; Prasad, R; Raffestin, D; Raimbourg, J; Rekow, V; Sangster, C; Song, P; Stoeckl, C; Stowell, M L; Teran, J M; Throop, A; Tommasini, R; Vierne, J; White, D; Whitman, P

    2009-10-05

    The generation of neutron/gamma radiation, electromagnetic pulses (EMP), debris and shrapnel at mega-Joule class laser facilities (NIF and LMJ) impacts experiments conducted at these facilities. The complex 3D numerical codes used to assess these impacts range from an established code that required minor modifications (MCNP - calculates neutron and gamma radiation levels in complex geometries), through a code that required significant modifications to treat new phenomena (EMSolve - calculates EMP from electrons escaping from laser targets), to a new code, ALE-AMR, that is being developed through a joint collaboration between LLNL, CEA, and UC (UCSD, UCLA, and LBL) for debris and shrapnel modelling.

  13. Cooling of relativistic electron beams in intense laser pulses: Chirps and radiation

    NASA Astrophysics Data System (ADS)

    Yoffe, S. R.; Noble, A.; Macleod, A. J.; Jaroszynski, D. A.

    2016-09-01

    Next-generation high-power laser facilities (such as the Extreme Light Infrastructure) will provide unprecedented field intensities, and will allow us to probe qualitatively new physical regimes for the first time. One of the important fundamental questions which will be addressed is particle dynamics when radiation reaction and quantum effects play a significant role. Classical theories of radiation reaction predict beam cooling in the interaction of a relativistic electron bunch and a high-intensity laser pulse, with final-state properties only dependent on the laser fluence. The observed quantum suppression of this cooling instead exhibits a dependence on the laser intensity directly. This offers the potential for final-state properties to be modified or even controlled by tailoring the intensity profile of the laser pulse. In addition to beam properties, quantum effects will be manifest in the emitted radiation spectra, which could be manipulated for use as radiation sources. We compare predictions made by classical, quasi-classical and stochastic theories of radiation reaction, and investigate the influence of chirped laser pulses on the observed radiation spectra.

  14. Pulsed radiation-induced attenuation in certain optical fibers

    SciTech Connect

    Weiss, J.D. )

    1992-05-01

    Using the X-ray pulse from the HERMES II simulation machine at Sandia National Laboratories, the pulsed radiation-induced attenuation was measured in two optical fibers considered to be 'nonrad-hard': the 50-micron-core, graded-index fiber from Corning and the plastic (PMMA) fiber from the Mitsubishi Rayon Company. These fibers were exposed to radiation up to doses of 19.5 and 28 krad(Si), respectively. In addition, fits of their post-radiation recovery were made to the geminate recombination model, from which the recombination-rate and generation constants, characteristic of this theory, were determined. These parameters should be useful in determining the response of the fibers to radiation conditions other than those encountered here. 18 refs.

  15. Radiation-driven hydrodynamics of high- hohlraums on the national ignition facility.

    PubMed

    Dewald, E L; Suter, L J; Landen, O L; Holder, J P; Schein, J; Lee, F D; Campbell, K M; Weber, F A; Pellinen, D G; Schneider, M B; Celeste, J R; McDonald, J W; Foster, J M; Niemann, C; Mackinnon, A J; Glenzer, S H; Young, B K; Haynam, C A; Shaw, M J; Turner, R E; Froula, D; Kauffman, R L; Thomas, B R; Atherton, L J; Bonanno, R E; Dixit, S N; Eder, D C; Holtmeier, G; Kalantar, D H; Koniges, A E; Macgowan, B J; Manes, K R; Munro, D H; Murray, J R; Parham, T G; Piston, K; Van Wonterghem, B M; Wallace, R J; Wegner, P J; Whitman, P K; Hammel, B A; Moses, E I

    2005-11-18

    The first hohlraum experiments on the National Ignition Facility (NIF) using the initial four laser beams tested radiation temperature limits imposed by plasma filling. For a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with an analytical model that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits with full NIF (1.8 MJ), greater, and of longer duration than required for ignition hohlraums. PMID:16384150

  16. Xenon plasma sustained by pulse-periodic laser radiation

    SciTech Connect

    Rudoy, I. G.; Solovyov, N. G.; Soroka, A. M.; Shilov, A. O.; Yakimov, M. Yu.

    2015-10-15

    The possibility of sustaining a quasi-stationary pulse-periodic optical discharge (POD) in xenon at a pressure of p = 10–20 bar in a focused 1.07-μm Yb{sup 3+} laser beam with a pulse repetition rate of f{sub rep} ⩾ 2 kHz, pulse duration of τ ⩾ 200 μs, and power of P = 200–300 W has been demonstrated. In the plasma development phase, the POD pulse brightness is generally several times higher than the stationary brightness of a continuous optical discharge at the same laser power, which indicates a higher plasma temperature in the POD regime. Upon termination of the laser pulse, plasma recombines and is then reinitiated in the next pulse. The initial absorption of laser radiation in successive POD pulses is provided by 5p{sup 5}6s excited states of xenon atoms. This kind of discharge can be applied in plasma-based high-brightness broadband light sources.

  17. Quantization effects in radiation spectroscopy based on digital pulse processing

    SciTech Connect

    Jordanov, V. T.; Jordanova, K. V.

    2011-07-01

    Radiation spectra represent inherently quantization data in the form of stacked channels of equal width. The spectrum is an experimental measurement of the discrete probability density function (PDF) of the detector pulse heights. The quantization granularity of the spectra depends on the total number of channels covering the full range of pulse heights. In analog pulse processing the total number of channels is equal to the total digital values produced by a spectroscopy analog-to-digital converter (ADC). In digital pulse processing each detector pulse is sampled and quantized by a fast ADC producing certain number of quantized numerical values. These digital values are linearly processed to obtain a digital quantity representing the peak of the digitally shaped pulse. Using digital pulse processing it is possible to acquire a spectrum with the total number of channels greater than the number of ADC values. Noise and sample averaging are important in the transformation of ADC quantized data into spectral quantized data. Analysis of this transformation is performed using an area sampling model of quantization. Spectrum differential nonlinearity (DNL) is shown to be related to the quantization at low noise levels and small number of averaged samples. Theoretical analysis and experimental measurements are used to obtain the condition to minimize the DNL due to quantization. (authors)

  18. Atlas Pulsed Power Facility for High Energy Density Physics Experiments

    SciTech Connect

    Miller, R.B.; Ballard, E.O.; Barr, G.W.; Bowman, D.W.; Chochrane, J.C.; Davis, H.A.; Elizondo, J.M.; Gribble, R.F.; Griego, J.R.; Hicks, R.D.; Hinckley, W.B.; Hosack, K.W.; Nielsen, K.E.; Parker, J.V.; Parsons, M.O.; Rickets, R.L.; Salazar, H.R.; Sanchez, P.G.; Scudder, D.W.; Shapiro, C.; Thompson, M.C.; Trainor, R.J.; Valdez, G.A.; Vigil, B.N.; Watt, R.G.; Wysock, F.J.

    1999-06-07

    The Atlas facility, now under construction at Los Alamos National Laboratory (LANL), will provide a unique capability for performing high-energy-density experiments in support of weapon-physics and basic-research programs. It is intended to be an international user facility, providing opportunities for researchers from national laboratories and academic institutions around the world. Emphasizing institutions around the world. Emphasizing hydrodynamic experiments, Atlas will provide the capability for achieving steady shock pressures exceeding 10-Mbar in a volume of several cubic centimeters. In addition, the kinetic energy associated with solid liner implosion velocities exceeding 12 km/s is sufficient to drive dense, hydrodynamic targets into the ionized regime, permitting the study of complex issues associated with strongly-coupled plasmas. The primary element of Atlas is a 23-MJ capacitor bank, comprised of 96 separate Marx generators housed in 12 separate oil-filled tanks, surrounding a central target chamber. Each tank will house two, independently-removable maintenance units, with each maintenance unit consisting of four Marx modules. Each Marx module has four capacitors that can each be charged to a maximum of 60 kilovolts. When railgap switches are triggered, the marx modules erect to a maximum of 240 kV. The parallel discharge of these 96 Marx modules will deliver a 30-MA current pulse with a 4-5-{micro}s risetime to a cylindrical, imploding liner via 24 vertical, tri-plate, oil-insulated transmission lines. An experimental program for testing and certifying all Marx and transmission line components has been completed. A complete maintenance module and its associated transmission line (the First Article) are now under construction and testing. The current Atlas schedule calls for construction of the machine to be complete by August, 2000. Acceptance testing is scheduled to begin in November, 2000, leading to initial operations in January, 2001.

  19. Radiation from long pulse train electron beams in space plasmas

    NASA Technical Reports Server (NTRS)

    Harker, K. J.; Banks, P. M.

    1985-01-01

    A previous study of electromagnetic radiation from a finite train of electron pulses is extended to an infinite train of such pulses. The electrons are assumed to follow an idealized helical path through a space plasma in such a manner as to retain their respective position within the beam. This leads to radiation by coherent spontaneous emission. The waves of interest in this region are the whistler slow (compressional) and fast (torsional) Alfven waves. Although a general theory is developed, analysis is then restricted to two approximations, the short and long electron beam. Formulas for the radiation per unit solid angle from the short beam are presented as a function of both propagation and ray angles, electron beam pulse width and separation and beam current, voltage, and pitch angle. Similar formulas for the total power radiated from the long beam are derived as a function of frequency, propagation angle, and ray angle. Predictions of the power radiated are presented for representative examples as determined by the long beam theory.

  20. The NHMFL Pulsed Field Facility at Los Alamos National Lab

    NASA Astrophysics Data System (ADS)

    Mielke, Chuck

    2014-03-01

    National user facilities provide scientists and industrial development companies with access to specialized experimental capabilities to enable development of materials and solve long standing technical problems. Magnetic fields have become an indispensable tool for researchers to better understand and manipulate ground states of electronic materials. As magnetic field intensities are increased the quantum nature of these materials become exponentially more likely to be observed and this is but one of the drivers to go further in high magnetic field generation. At the Los Alamos branch of the National High Magnetic Field Laboratory we have significant efforts in extremely high magnetic field generation and experimentation. In direct opposition with our efforts are the tremendous electro-mechanical forces exerted on our magnets and the electromagnetic interference that couples to the sample under study and the diagnostic equipment. Challenges in magnetic field generation and research will be presented. Various methods of pulsed high magnetic field generation and experimentation capabilities will be reviewed, including our recent ``World Record'' for the highest non-destructive magnetic field. NSF-DMR 1157490.

  1. Characterization of a medical X-ray machine for testing the response of electronic dosimeters in pulsed radiation fields

    NASA Astrophysics Data System (ADS)

    Guimarães, Margarete C.; Da Silva, Teógenes A.

    2014-11-01

    Electronic personal dosimeters (EPD) based on solid state detectors have been used for personnel monitoring for radiation protection purpose; their use has been extended to practices with pulsed radiation beams although their performance is not well known. Deficiencies in the EPD response in pulsed radiation fields have been reported; they were not detected before since type tests and calibrations of EPDs were established in terms of continuous X and gamma reference radiations. An ISO working group was formed to elaborate a standard for test conditions and performance requirements of EPDs in pulsed beams; the PTB/Germany implemented a special X-ray facility for generating the reference pulsed radiation beams. In this work, an 800 Plus VMI medical X-ray machine of the Dosimeter Calibration Laboratory of CDTN/CNEN was characterized to verify its feasibility to perform EPD tests. Characterization of the x-ray beam was done in terms of practical peak voltage, half-value layer, mean energy and air kerma rate. Reference dosimeters used for air kerma measurements were verified as far their metrological coherence and a procedure for testing EDPs was established. Electronic personal dosimeters (EPD) have been used for personnel monitoring. EPD use has been extended to pulsed radiation beams. Deficiencies in the EPD response in pulsed beams have been reported. The feasibility of using a medical X-ray machine to perform EPD tests was studied. Reference dosimeters were verified and EPD testing procedure was established.

  2. Pulsed electron accelerator for radiation technologies in the enviromental applications

    NASA Astrophysics Data System (ADS)

    Korenev, Sergey

    1997-05-01

    The project of pulsed electron accelerator for radiation technologies in the environmental applications is considered. An accelerator consists of high voltage generator with vacuum insulation and vacuum diode with plasma cathode on the basis discharge on the surface of dielectric of large dimensions. The main parameters of electron accelerators are following: kinetic energy 0.2 - 2.0 MeV, electron beam current 1 - 30 kA and pulse duration 1- 5 microseconds. The main applications of accelerator for decomposition of wastewaters are considered.

  3. Interaction of repetitively pulsed high energy laser radiation with matter

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, M.

    1986-05-01

    Laser target interaction processes and methods of improving the overall energy balance are discussed. This can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed using a pulsed CO2 laser at mean powers up to 2 KW and repetition rates up to 100 Hz. The rates of temperature rise of aluminum for example are increased by more than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements are found for the overall absorptivities, that are increased by more than an order of magnitude.

  4. Short Pulse Experimental Capability at the Nike Laser Facility

    NASA Astrophysics Data System (ADS)

    Weaver, J. L.; Chan, Y.; Gardner, J.; Giuliani, J.; Karasik, M.; Kehne, D.; Mostovych, A.; Obenschain, S.; Velikovich, A.; Schmitt, A.; Serlin, V.; Aglitskiy, Y.; Metzler, N.; Smyth, Z.; Terrell, S.

    2004-11-01

    Recent simulations demonstrated high gain for direct drive pellets compressed by a laser pulse incorporating a short pulse prior to the main pulse. Theoretical work has also shown that a short prepulse can create a tailored density profile that reduces the initial instability growth due to laser imprinting. A new short pulse (0.35-0.75 ns FWHM)is being added to the Nike KrF laser system to facilitate hydrodynamic experiments with short prepulses. This capability has been incorporated into the initial stages of the laser system and the propagation of these pulses through the angularly multiplexed amplifiers is being studied. Measurements of pulse shape and energy will be compared to simulations using the KrF physics code Orestes for the next to last amplifier of the laser system, the 20 cm x 20 cm e-beam pumped laser cell. The effects of amplified spontaneous emission (ASE) upon individual output pulses will be also discussed.

  5. Radiation safety training for accelerator facilities

    SciTech Connect

    Trinoskey, P.A.

    1997-02-01

    In November 1992, a working group was formed within the U.S. Department of Energy`s (DOE`s) accelerator facilities to develop a generic safety training program to meet the basic requirements for individuals working in accelerator facilities. This training, by necessity, includes sections for inserting facility-specific information. The resulting course materials were issued by DOE as a handbook under its technical standards in 1996. Because experimenters may be at a facility for only a short time and often at odd times during the day, the working group felt that computer-based training would be useful. To that end, Lawrence Livermore National Laboratory (LLNL) and Argonne National Laboratory (ANL) together have developed a computer-based safety training program for accelerator facilities. This interactive course not only enables trainees to receive facility- specific information, but time the training to their schedule and tailor it to their level of expertise.

  6. Comparison of fission neutron and pulsed spallation neutron sources for radiation effects experiments on Cu/sub 3/Au

    SciTech Connect

    Kirk, M.A.

    1983-10-01

    Through our recent experimental work on the neutron irradiation effects in Cu/sub 3/Au, we will compare fission and pulsed spallation neutron sources. Neutron characteristics of irradiation facilities at the Intense Pulsed Neutron Source (IPNS) and the CP-5 reactor (now closed down), are briefly described. Defect cascade size distributions from irradiations of Cu/sub 3/Au at both neutron sources illustrated by transmission electron micrographs of disordered zones. Radiation-enhanced diffusion experiments in Cu/sub 3/Au are discussed along with the effect of pulsed neutron irradiations.

  7. Successful Treatment of Occipital Radiating Headache Using Pulsed Radiofrequency Therapy

    PubMed Central

    Lee, Sun Yeul; Jang, Dae Il; Noh, Chan

    2015-01-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease involving multiple joints. The cervical spine is often affected, and cases involving atlantoaxial joint can lead to instability. Anterior atlantoaxial subluxation in RA patients can lead to posterior neck pain or occipital headache because of compression of the C2 ganglion or nerve. Here, we report the successful treatment of a RA patient with occipital radiating headache using pulsed radiofrequency therapy at the C2 dorsal root ganglion. PMID:26279821

  8. Design considerations and test facilities for accelerated radiation effects testing

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Miller, C. G.; Parker, R. H.

    1972-01-01

    Test design parameters for accelerated dose rate radiation effects tests for spacecraft parts and subsystems used in long term mission (years) are detailed. A facility for use in long term accelerated and unaccelerated testing is described.

  9. Comparative investigation of three dose rate meters for their viability in pulsed radiation fields.

    PubMed

    Gotz, M; Karsch, L; Pawelke, J

    2015-06-01

    Pulsed radiation fields, characterized by microsecond pulse duration and correspondingly high pulse dose rates, are increasingly used in therapeutic, diagnostic and research applications. Yet, dose rate meters which are used to monitor radiation protection areas or to inspect radiation shielding are mostly designed, characterized and tested for continuous fields and show severe deficiencies in highly pulsed fields. Despite general awareness of the problem, knowledge of the specific limitations of individual instruments is very limited, complicating reliable measurements. We present here the results of testing three commercial dose rate meters, the RamION ionization chamber, the LB 1236-H proportional counter and the 6150AD-b scintillation counter, for their response in pulsed radiation fields of varied pulse dose and duration. Of these three the RamION proved reliable, operating in a pulsed radiation field within its specifications, while the other two instruments were only able to measure very limited pulse doses and pulse dose rates reliably. PMID:25978117

  10. Atmospheric radiation measurement program facilities newsletter, September 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-10-02

    This Atmospheric radiation measurement program facilities newsletter covers the following topics: The Raman lidar at the SGP central facility is receiving upgrades to its environmental controls; The instrument tower at Okmulgee State Park is receiving upgrades to prevent Turkey Vultures from roosting on the booms.

  11. Accuracy of Analog Fiber-Optic Links in Pulsed Radiation Environments

    SciTech Connect

    E. K. Miller, G. S. Macrum, I. J. McKenna, et al.

    2007-12-01

    Interferometric fiber-optic links used in pulsed-power experiments are evaluated for accuracy in the presence of radiation fields which alter fiber transmission. Amplitude-modulated format (e.g., Mach-Zehnder) and phase-modulated formats are compared. Historically, studies of radiation effects on optical fibers have focused on degradation and recovery of the fibers transmission properties; such work is either in the context of survivability of fibers in catastrophic conditions or suitability of fibers installed for command and control systems within an experimental facility [1], [2]. In this work, we consider links used to transmit realtime diagnostic data, and we analyze the error introduced by radiation effects during the drive pulse. The result is increased uncertainties in key parameters required to unfold the sinusoidal transfer function. Two types of modulation are considered: amplitude modulation typical of a Mach-Zehnder (M-Z) modulator [3], and phase modulation, which offers more flexible demodulation options but relies on the spatiotemporal coherence of the light in the fiber. The M-Z link is shown schematically in Fig. 1, and the phase-modulated link is shown in Fig. 2. We present data from two experimental environments: one with intense, controlled radiation fields to simulate conditions expected at the next generation of pulsed-power facilities, and the second with radiation effects below the noise level of the recording system. In the first case, we intentionally expose three types of single-mode fiber (SMF) to ionizing radiation and study the response by simultaneously monitoring phase and amplitude of the transmitted light. The phase and amplitude effects are evidently dominated by different physical phenomena, as their recovery dynamics are markedly different; both effects, though, show similar short-term behavior during exposure, integrating the dose at the dose levels studied, from 1 to 300 kRad, over the exposure times of 50 ps and 30 ns. In the

  12. Shielding and Radiation Protection in Ion Beam Therapy Facilities

    NASA Astrophysics Data System (ADS)

    Wroe, Andrew J.; Rightnar, Steven

    Radiation protection is a key aspect of any radiotherapy (RT) department and is made even more complex in ion beam therapy (IBT) by the large facility size, secondary particle spectra and intricate installation of these centers. In IBT, large and complex radiation producing devices are used and made available to the public for treatment. It is thus the responsibility of the facility to put in place measures to protect not only the patient but also the general public, occupationally and nonoccupationally exposed personnel working within the facility, and electronics installed within the department to ensure maximum safety while delivering maximum up-time.

  13. Explosive pulsed power system for new radiation sources.

    SciTech Connect

    Oona, H.; Goforth, J. H.; Idzorek, G. C.; Herrera, D. H.; King, J. C.; Lopez, E. A.; Tasker, D. G.; Torres, D. T.

    2004-01-01

    High explosive pulsed power (HEPP) systems are capable of accessing very high energy densities and can reach conditions that are not possible with capacitor bank systems. The Procyon system was developed and used for experiments over a period of six years, and is exemplary of the capabilities of HEPP systems for state-of-the-art research. In this paper we will summarize some of the more interesting aspects of the work done in the past but will suggest ideas toward applications for future research. One of the main, unique features of HEPP systems is that they integrate easily to a particular physics experiment and the power flow can be optimized for a specific test. Magnetic flux compression generators have been an ideal power source for both high current plasma physics and hydrodynamic experimental loads. These experiments have contributed greatly to the understanding of high temperature and density plasmas and more recently to the understanding of instability growth in thick ({approx}1 mm) imploding metal cylinders. Common to all these experiments is the application of a large current pulse to a cylindrically symmetric load. The resulting Lorenz force compresses the load to produce hydrodynamic motion and/or high temperature, high density plasma. In the plasma physics experiments, plasma thermalizes on axis and a black body distribution of x-rays is produced. To get better access to the radiation pulse, the load electrode geometry was modified. For example, by shaping the plasma implosion glide planes, a mass depletion region was formed along one electrode at pinch time which generated a very large voltage drop across a 1-2 mm segment of the pinch, and also produced a high energy ion beam on axis. These results were predicted by magneto-hydro-dynamic (MHD) codes and verified with framing camera and x-ray, pinhole, camera pictures. We have not previously published these features but will take another look and propose possible scenarios for studying and generating

  14. Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, Manfred

    1986-10-01

    The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

  15. Gas-Monitor Detector for Intense and Pulsed VUV/EUV Free-Electron Laser Radiation

    NASA Astrophysics Data System (ADS)

    Sorokin, A. A.; Bobashev, S. V.; Feldhaus, J.; Gerth, Ch.; Gottwald, A.; Hahn, U.; Kroth, U.; Richter, M.; Shmaenok, L. A.; Steeg, B.; Tiedtke, K.; Treusch, R.

    2004-05-01

    In the framework of current developments of new powerful VUV and EUV radiation sources, like VUV free-electron-lasers or EUV plasma sources for 13-nm lithography, we developed a gas-monitor detector in order to measure the photon flux of highly intense and extremely pulsed VUV and EUV radiation in absolute terms. The device is based on atomic photoionization of a rare gas at low particle density. Therefore, it is free of degradation and almost transparent, which allows the detector to be used as a continuously working beam-intensity monitor. The extended dynamic range of the detector allowed its calibration with relative standard uncertainties of 4% in the Radiometry Laboratory of the Physikalisch-Technische Bundesanstalt at the electron-storage ring BESSY II in Berlin using spectrally dispersed synchrotron radiation at low photon intensities and its utilization for absolute photon flux measurements of high power sources. In the present contribution, we describe the design of the detector and its application for the characterization of VUV free-electron-laser radiation at the TESLA test facility in Hamburg. By first pulse resolved measurements, a peak power of more than 100 MW at a wavelength of 87 nm was detected.

  16. Computer program for pulsed thermocouples with corrections for radiation effects

    NASA Technical Reports Server (NTRS)

    Will, H. A.

    1981-01-01

    A pulsed thermocouple was used for measuring gas temperatures above the melting point of common thermocouples. This was done by allowing the thermocouple to heat until it approaches its melting point and then turning on the protective cooling gas. This method required a computer to extrapolate the thermocouple data to the higher gas temperatures. A method that includes the effect of radiation in the extrapolation is described. Computations of gas temperature are provided, along with the estimate of the final thermocouple wire temperature. Results from tests on high temperature combustor research rigs are presented.

  17. Materials evaluations with the pulsed black liquor burner test facility

    SciTech Connect

    Stein, A.

    1997-08-01

    A pulsed burner was designed to provide sufficient heat to convert a fluidized bed of black Kraft liquor into combustible gas which would be used to produce process steam. The pulsed burner design provides a significant increase in the heat transfer capability and consequently significantly increases the efficiency of the conversion process. High temperature corrosion tests were performed in a fluidized bed of black Kraft liquor using a pulsed burner process to determine the optimum materials for use in a commercial application. The materials tested included three different austenitic stainless steels, Type 446 martensitic stainless steel, a high temperature carbon steel, 153MA, and four nickel base alloys. All materials performed well with no corrosion attributed to the environment created by the decomposition of a black Kraft liquor. This behavior was contrary to what was expected due to the high concentration of H{sub 2}S present in the high temperature, 562 C, atmosphere.

  18. Design and characterisation of a pulsed neutron interrogation facility.

    PubMed

    Favalli, A; Pedersen, B

    2007-01-01

    The Joint Research Centre recently obtained a license to operate a new experimental device intended for research in the field of nuclear safeguards. The research projects currently being planned for the new device includes mass determination of fissile materials in matrices and detection of contraband non-nuclear materials. The device incorporates a commercial pulsed neutron generator and a large graphite mantle surrounding the sample cavity. In this configuration, a relatively high thermal neutron flux with a long lifetime is achieved inside the sample cavity. By pulsing the neutron generator, a sample may be interrogated by a pure thermal neutron flux during repeated time periods. The paper reports on the design of the new device and the pulsed fast and thermal neutron source. The thermal neutron flux caused by the neutron generator and the graphite structure has been characterised by foil activation, fission chamber and (3)He proportional counter measurements. PMID:17496298

  19. Radiation properties of Turkish light source facility TURKAY

    NASA Astrophysics Data System (ADS)

    Nergiz, Zafer

    2015-09-01

    The synchrotron light source TURKAY, which is one of the sub-project of Turkish Accelerator Center (TAC), has been supported by Ministry of Development of Turkey since 2006. The facility is designed to generate synchrotron radiation (SR) in range 0.01-60 keV from a 3 GeV storage ring with a beam emittance of 0.51 nm rad. Synchrotron radiation will be produced from the bending magnets and insertion devices in the storage ring. In this paper design studies for possible devices to produce synchrotron radiation and radiation properties of these devices with TURKAY storage ring parameters are presented.

  20. Development of short pulse laser driven micro-hohlraums as a source of EUV radiation

    NASA Astrophysics Data System (ADS)

    Krushelnick, Karl; Batson, Thomas; McKelvey, Andrew; Raymond, Anthony; Thomas, Alec; Yanovsky, Victor; Nees, John; Maksimchuk, Anatoly

    2015-11-01

    Experiments at large scale laser facilities such as NIF allow the radiativ properties of dens, high-temperature matter to be studied at previously unreachable regime, but are limited by cost and system availability. A scaled system using a short laser pulses and delivering energy to much smaller hohlraum could be capable of reaching comparable energy densities by depositing the energy in a much smaller volume before ablation of the wall material closes the cavit. The laser is tightl focused through the cavity and then expands to illuminate the wall. Experiments were performe using the Hercules Ti:Sapphire laser system at Michiga. Targets include cavities machined in bulk material using low laser power, and then shot in situ with a single full power pulse as well as micron scale pre-fabricate target. Spectral characteristics were measured using a soft X-ray spectromete, K-alpha x-ray imaging system and a filtered photo cathode array. Scalings of the radiation temperature were made for variations in the hohlraum cavit, the pulse duration as well as the focusing conditions. Proof of principle time resolved absorption spectroscopy experiments were also performe. These sources may allow opacity and atomic physics measurements with plasma an radiation temperatures comparable to much larger hohlraums, but with much higher repetition rate and in a university scale laboratory. We acknowledge funding from DTRA grant HDTRA1-11-1-0066.

  1. Ocular effects of pulsed neodymium laser radiation: variation of threshold with pulse width. Final report

    SciTech Connect

    Allen, R.G.; Thomas, S.J.; Harrison, R.F.; Zuclich, J.A.; Blankenstein, M.F.

    1985-11-01

    This study of retinal damage thresholds in the rhesus monkey investigated the effects of Nd:YAG laser radiation at four pulsewidths: 4, 30, and 200 nansec, and 10 microsecs. The thresholds causing minimal, ophthalmoscopically visible lesions for the four pulsewidths were 158, 326, 170, and 425 micron j respectively, incident at the eye in single-pulse exposures. The data are interpreted to imply a flat trend for thresholds at pulsewidths examined. This agrees with the maximum permissible exposures set by current safety standards. This finding contrasts with the hypothesis of an anomalous trend of increasing threshold with decreasing pulsewidth suggested for pulsewidths ranging from nanosec-microsecs.

  2. ARTICLES: Thermohydrodynamic models of the interaction of pulse-periodic radiation with matter

    NASA Astrophysics Data System (ADS)

    Arutyunyan, R. V.; Baranov, V. Yu; Bol'shov, Leonid A.; Malyuta, D. D.; Mezhevov, V. S.; Pis'mennyĭ, V. D.

    1987-02-01

    Experimental and theoretical investigations were made of the processes of drilling and deep melting of metals by pulsed and pulse-periodic laser radiation. Direct photography of the surface revealed molten metal splashing due to interaction with single CO2 laser pulses. A proposed thermohydrodynamic model was used to account for the experimental results and to calculate the optimal parameters of pulse-periodic radiation needed for deep melting. The melt splashing processes were simulated numerically.

  3. Radiation-induced insulator discharge pulses in the CRRES Internal Discharge Monitor satellite experiment. [Combined Release and Radiation Effects Satellite

    NASA Technical Reports Server (NTRS)

    Frederickson, A. R.; Mullen, E. G.; Brautigam, D. H.; Kerns, K. J.; Robinson, P. A., Jr.; Holman, E. G.

    1991-01-01

    The Internal Discharge Monitor (IDM) is designed to observe electrical pulses from common electrical insulators in space service. The IDM is flying on the Combined Release and Radiation Effects Satellite (CRRES). The sixteen insulator samples include G10 circuit boards, FR4 and PTFE fiberglass circuit boards, FEP Teflon, alumina, and wires with common insulations. The samples are fully enclosed, mutually isolated, and space radiation penetrates 0.02 cm of aluminum before striking the samples. The IDM results indicate the rate at which insulator pulses occur. Pulsing began on the seventh orbit. The maximum pulse rate occurred near orbit 600 when over 50 pulses occurred. The average pulse rate is approximately two per orbit, but nearly half of the first 600 orbits experienced no pulses. The pulse rate per unit flux of high energy electrons has not changed dramatically over the first ten months in space. These pulse rates are in agreement with laboratory experience on shorter time scales. Several of the samples have never pulsed. IDM pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on CRRES.

  4. Scintillator characterization using the LBL Pulsed X-ray Facility

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.; Weber, M.J.; Blankespoor, S.C.; Ho, M.H.; West, A.C.

    1994-10-01

    The authors have developed a bench-top pulsed x-ray system for measuring scintillation properties of compounds in crystal or powdered form. The source is a light-excited x-ray tube that produces 40 x-ray photons (mean energy 18.5 keV) per steradian in each 100 ps fwhm pulse. The repetition rate is adjustable from 0 to 10{sup 7} pulses per second. The fluorescent emanations from the x-ray excited samples are detected with either a sapphire-windowed microchannel plate photomultiplier tube (spectral range 150--650 nm, transit time jitter 40 ps fwhm) or a quartz windowed GaAs(Cs) photomultiplier tube (spectral range 160--930 nm, transit time jitter 4 ns fwhm). Decay time spectra are acquired using a TDC Havina 40 ps fwhm resolution over a 84 ms dynamic range. A computer controlled monochromator can be inserted into the optical path to measure the emission spectrum or wavelength resolved decay time spectrum. A computer controlled sample changer allows up to 64 samples to be measured without intervention.

  5. Design concepts for a pulse power test facility to simulate EMP surges in overhead power lines. Part I. Fast pulse

    SciTech Connect

    Ramrus, A.

    1986-02-01

    Objective of the study was to create conceptual designs of high voltage pulsers capable of simulating two types of electromagnetic pulses (EMPs) caused by a high-altitude nuclear burst; the slow rise time magnetohydrodynamic (MHD-EMP) and the fast rise time high-altitude EMP (HEMP). The pulser design was directed towards facilities capable of performing EMP vulnerability testing of components used in the national electric power system.

  6. Radiation-induced insulator discharge pulses in the CRRES internal discharge monitor satellite experiment

    NASA Technical Reports Server (NTRS)

    Frederickson, A. R.; Mullen, E. G.; Brautigam, D. H.; Kerns, K. J.

    1992-01-01

    The Internal Discharge Monitor (IDM) was designed to observe electrical pulses from common electrical insulators in space service. The sixteen insulator samples included twelve planar printed circuit boards and four cables. The samples were fully enclosed, mutually isolated, and space radiation penetrated 0.02 cm of aluminum before striking the samples. Pulsing began on the seventh orbit, the maximum pulse rate occurred on the seventeenth orbit when 13 pulses occurred, and the pulses slowly diminished to about one per 3 orbits six months later. After 8 months, the radiation belts abruptly increased and the pulse rates attained a new high. These pulse rates were in agreement with laboratory experience on shorter time scales. Several of the samples never pulsed. If the pulses were not confined within IDM, the physical processes could spread to become a full spacecraft anomaly. The IDM results indicate the rate at which small insulator pulses occur. Small pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on the Combined Release and Radiation Effects Satellite.

  7. A guide to design of radiation therapy facilities.

    PubMed

    Galvin, J M; Claytor, N; Cedrone, B; Graff, R L

    1985-01-01

    The design technique outline provides the information needed to develop a layout for a new or renovated radiation therapy department. The department described is a medium-sized facility with two megavoltage linear accelerators and a single simulator. The plans for an expansion to include another linear accelerator and a neutron generator also are presented. PMID:10270908

  8. 31. SECTIONS AND DETAILS OF ARVFS FACILITY, INCLUDING RADIATION HAZARD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. SECTIONS AND DETAILS OF ARVFS FACILITY, INCLUDING RADIATION HAZARD SIGN, WOOD RETAINING WALL, TANK COVER, AND DRAIN BOX. F.C. TORKELSON DRAWING NUMBER 842-ARVFS-701-3. INEL INDEX CODE NUMBER: 075 0701 851 151972. - Idaho National Engineering Laboratory, Advanced Reentry Vehicle Fusing System, Scoville, Butte County, ID

  9. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2008

    SciTech Connect

    LR Roeder

    2008-12-01

    The Importance of Clouds and Radiation for Climate Change: The Earth’s surface temperature is determined by the balance between incoming solar radiation and thermal (or infrared) radiation emitted by the Earth back to space. Changes in atmospheric composition, including greenhouse gases, clouds, and aerosols, can alter this balance and produce significant climate change. Global climate models (GCMs) are the primary tool for quantifying future climate change; however, there remain significant uncertainties in the GCM treatment of clouds, aerosol, and their effects on the Earth’s energy balance. In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program to address scientific uncertainties related to global climate change, with a specific focus on the crucial role of clouds and their influence on the transfer of radiation in the atmosphere. To reduce these scientific uncertainties, the ARM Program uses a unique twopronged approach: • The ARM Climate Research Facility, a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes; and • The ARM Science Program, focused on the analysis of ACRF and other data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report provides an overview of each of these components and a sample of achievements for each in fiscal year (FY) 2008.

  10. Pulsed mid-infrared radiation from spectral broadening in laser wakefield simulations

    SciTech Connect

    Zhu, W.; Palastro, J. P.; Antonsen, T. M.

    2013-07-15

    Spectral red-shifting of high power laser pulses propagating through underdense plasma can be a source of ultrashort mid-infrared (MIR) radiation. During propagation, a high power laser pulse drives large amplitude plasma waves, depleting the pulse energy. At the same time, the large amplitude plasma wave provides a dynamic dielectric response that leads to spectral shifting. The loss of laser pulse energy and the approximate conservation of laser pulse action imply that spectral red-shifts accompany the depletion. In this paper, we investigate, through simulation, the parametric dependence of MIR generation on pulse energy, initial pulse duration, and plasma density.

  11. Outline of a proposal for a new neutron source: The pulsed neutron research facility

    SciTech Connect

    Brown, B.S.; Carpenter, J.M.; Kustom, R.L.

    1992-04-01

    Accelerator-based, pulsed spallation neutron sources have been performing neutron scattering research for about fifteen years. During this time beam intensities have increased by a factor of 100 and more than 50 spectrometers are now operating on four major sources worldwide. The pulsed sources have proven to be highly effective and complementary to reactor-based sources in that there are important scientific areas for which each type of source has unique capabilities. We describe a proposal for a new pulsed neutron facility based on a Fixed Field Alternating Gradient synchrotron. The specifications for this new machine, which are now only being formulated, are for an accelerator that will produce (100 {divided_by} 200) {mu}A of time-averaged proton current at (500 {divided_by} 1000) MeV, in short pulses at 30 Hz. Appropriate target and moderator systems and an array of scattering instruments will be provided to make the facility a full-blown research installation. The neutron source, named the Pulsed Neutron Research Facility (PNRF), will be as powerful as any pulsed source now operating in the world and will also act as a test bed for the Fixed Field Alternating Gradient Synchrotron concept as a basis for more powerful sources in the future. The peak thermal neutron flux in PNRF will be about 5{center_dot}10{sup 15}n/cm{sup 2}{center_dot}s.

  12. Outline of a proposal for a new neutron source: The pulsed neutron research facility

    SciTech Connect

    Brown, B.S.; Carpenter, J.M.; Kustom, R.L.

    1992-04-01

    Accelerator-based, pulsed spallation neutron sources have been performing neutron scattering research for about fifteen years. During this time beam intensities have increased by a factor of 100 and more than 50 spectrometers are now operating on four major sources worldwide. The pulsed sources have proven to be highly effective and complementary to reactor-based sources in that there are important scientific areas for which each type of source has unique capabilities. We describe a proposal for a new pulsed neutron facility based on a Fixed Field Alternating Gradient synchrotron. The specifications for this new machine, which are now only being formulated, are for an accelerator that will produce (100 {divided by} 200) {mu}A of time-averaged proton current at (500 {divided by} 1000) MeV, in short pulses at 30 Hz. Appropriate target and moderator systems and an array of scattering instruments will be provided to make the facility a full-blown research installation. The neutron source, named the Pulsed Neutron Research Facility (PNRF), will be as powerful as any pulsed source now operating in the world and will also act as a test bed for the Fixed Field Alternating Gradient Synchrotron concept as a basis for more powerful sources in the future. The peak thermal neutron flux in PNRF will be about 5{center dot}10{sup 15}n/cm{sup 2}{center dot}s.

  13. Detection of coincident radiations in a single transducer by pulse shape analysis

    DOEpatents

    Warburton, William K.; Tan, Hui; Hennig, Wolfgang

    2008-03-11

    Pulse shape analysis determines if two radiations are in coincidence. A transducer is provided that, when it absorbs the first radiation produces an output pulse that is characterized by a shorter time constant and whose area is nominally proportional to the energy of the absorbed first radiation and, when it absorbs the second radiation produces an output pulse that is characterized by a longer time constant and whose area is nominally proportional to the energy of the absorbed second radiation. When radiation is absorbed, the output pulse is detected and two integrals are formed, the first over a time period representative of the first time constant and the second over a time period representative of the second time constant. The values of the two integrals are examined to determine whether the first radiation, the second radiation, or both were absorbed in the transducer, the latter condition defining a coincident event.

  14. [RADIATION SAFETY DURING REMEDIATION OF THE "SEVRAO" FACILITIES].

    PubMed

    Shandala, N K; Kiselev, S M; Titov, A V; Simakov, A V; Seregin, V A; Kryuchkov, V P; Bogdanova, L S; Grachev, M I

    2015-01-01

    Within a framework of national program on elimination of nuclear legacy, State Corporation "Rosatom" is working on rehabilitation at the temporary waste storage facility at Andreeva Bay (Northwest Center for radioactive waste "SEVRAO"--the branch of "RosRAO"), located in the North-West of Russia. In the article there is presented an analysis of the current state of supervision for radiation safety of personnel and population in the context of readiness of the regulator to the implementation of an effective oversight of radiation safety in the process of radiation-hazardous work. Presented in the article results of radiation-hygienic monitoring are an informative indicator of the effectiveness of realized rehabilitation measures and characterize the radiation environment in the surveillance zone as a normal, without the tendency to its deterioration. PMID:26625607

  15. DAFNE-Light INFN-LNF Synchrotron Radiation Facility

    SciTech Connect

    Balerna, A.; Cestelli-Guidi, M.; Cimino, R.; Commisso, M.; Grilli, A.; Pietropaoli, M.; Raco, A.; Sciarra, V.; Tullio, V.; Viviani, G.; De Sio, A.; Gambicorti, L.; Hampai, D.; Pace, E.

    2010-06-23

    DAFNE-Light is the Synchrotron Radiation Facility at the INFN-Frascati National Laboratory (Rome, Italy). Three beamlines are operational, using in parasitic and dedicated mode the intense photon emission of DAFNE, a 0.51 GeV storage ring with a routinely circulating electron current higher than 1 Ampere. Two of these beamlines--the soft x-ray (DXR1) and UV (DXR2)--use one of the DAFNE wiggler magnets as synchrotron radiation source, while the third beamline SINBAD (Synchrotron Infrared Beamline At DAFNE) collects the radiation from a bending magnet. New XUV bending magnet beamlines are nowadays under construction and the low energy one (35-200 eV) will be ready for commissioning by the end of 2009. A presentation of the facility will be given together with some recent scientific results achieved at SINBAD and DXR1 beamlines.

  16. Symmetry tuning with megajoule laser pulses at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Kline, J. L.; Meezan, N. B.; Callahan, D. A.; Glenzer, S. H.; Kyrala, G. A.; Dixit, S. N.; Town, R. P. J.; Benedetti, R.; Bradley, D. K.; Bond, E.; Di Nicola, P.; Dewald, E. L.; Doeppner, T.; Glenn, S.; Haynam, C.; Heeter, R. F.; Hinkel, D. E.; Izumi, N.; Jancaitis, K.; Jones, O. S.; Kalantar, D.; Kilkenny, J.; LaFortune, K. N.; Landen, O.; Ma, T.; MacKinnon, A.; Michel, P.; Moody, J. D.; Moran, M.; Parham, T.; Prasad, R. R.; Radousky, H. B.; Ralph, J.; Schneider, M. B.; Simanovskaia, N.; Thomas, C. A.; Weber, S.; Widmann, K.; Widmayer, C.; Williams, E. A.; Van Wontergheman, B.; Edwards, M. J.; Suter, L. J.; Atherton, L. J.; MacGowan, B. J.

    2013-11-01

    Experiments conducted at the National Ignition Facility using shaped laser pulses with more than 1 MJ of energy have demonstrated the ability to control the implosion symmetry under ignition conditions. To achieve thermonuclear ignition, the low mode asymmetries must be small to minimize the size of the hotspot. The symmetry tuning experiments use symmetry capsules, "symcaps", which replace the DT fuel with an equivalent mass of CH to emulate the hydrodynamic behavior of an ignition capsule. The x-ray self-emission signature from gas inside the capsule during the peak compression correlates with the surrounding hotspot shape. By tuning the shape of the self-emission, the capsule implosion symmetry can be made to be "round." In the experimental results presented here, we utilized crossbeam energy transfer [S. H. Glenzer, et al., Science 327, 1228 (2010)] to change the ratio of the inner to outer cone power inside the hohlraum targets on the NIF. Variations in the ratio of the inner cone to outer cone power affect the radiation pattern incident on the capsule modifying the implosion symmetry.

  17. Optimized laser pulse profile for efficient radiation pressure acceleration of ions

    SciTech Connect

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

    2012-12-21

    The radiation pressure acceleration regime of laser ion acceleration requires high intensity laser pulses to function efficiently. Moreover the foil should be opaque for incident radiation during the interaction to ensure maximum momentum transfer from the pulse to the foil, which requires proper matching of the target to the laser pulse. However, in the ultrarela-tivistic regime, this leads to large acceleration distances, over which the high laser intensity for a Gaussian laser pulse must be maintained. It is shown that proper tailoring of the laser pulse profile can significantly reduce the acceleration distance, leading to a compact laser ion accelerator, requiring less energy to operate.

  18. Optimized laser pulse profile for efficient radiation pressure acceleration of ions

    SciTech Connect

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

    2012-09-15

    The radiation pressure acceleration regime of laser ion acceleration requires high intensity laser pulses to function efficiently. Moreover, the foil should be opaque for incident radiation during the interaction to ensure maximum momentum transfer from the pulse to the foil, which requires proper matching of the target to the laser pulse. However, in the ultrarelativistic regime, this leads to large acceleration distances, over which the high laser intensity for a Gaussian laser pulse must be maintained. It is shown that proper tailoring of the laser pulse profile can significantly reduce the acceleration distance, leading to a compact laser ion accelerator, requiring less energy to operate.

  19. The Radiation Dose Determination of the Pulsed X-ray Source

    NASA Astrophysics Data System (ADS)

    Miloichikova, I.; Stuchebrov, S.; Zhaksybayeva, G.; Wagner, A.

    2014-10-01

    In this paper the radiation dose measurement technique of the pulsed X-ray source RAP-160-5 is described. The dose rate measurement results from the pulsed X-ray beams at the different distance between the pulsed X-ray source focus and the detector obtained with the help of the thermoluminescent detectors DTL-02, the universal dosimeter UNIDOS E equipped with the plane-parallel ionization chamber type 23342, the dosimeter-radiometer DKS-96 and the radiation dosimeter AT 1123 are demonstrated. The recommendations for the dosimetry measurements of the pulsed X-ray generator RAP-160-5 under different radiation conditions are proposed.

  20. Intercomparison of radiation protection instrumentation in a pulsed neutron field

    NASA Astrophysics Data System (ADS)

    Caresana, M.; Denker, A.; Esposito, A.; Ferrarini, M.; Golnik, N.; Hohmann, E.; Leuschner, A.; Luszik-Bhadra, M.; Manessi, G.; Mayer, S.; Ott, K.; Röhrich, J.; Silari, M.; Trompier, F.; Volnhals, M.; Wielunski, M.

    2014-02-01

    In the framework of the EURADOS working group 11, an intercomparison of active neutron survey meters was performed in a pulsed neutron field (PNF). The aim of the exercise was to evaluate the performances of various neutron instruments, including commercially available rem-counters, personal dosemeters and instrument prototypes. The measurements took place at the cyclotron of the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. The cyclotron is routinely used for proton therapy of ocular tumours, but an experimental area is also available. For the therapy the machine accelerates protons to 68 MeV. The interaction of the proton beam with a thick tungsten target produces a neutron field with energy up to about 60 MeV. One interesting feature of the cyclotron is that the beam can be delivered in bursts, with the possibility to modify in a simple and flexible way the burst length and the ion current. Through this possibility one can obtain radiation bursts of variable duration and intensity. All instruments were placed in a reference position and irradiated with neutrons delivered in bursts of different intensity. The analysis of the instrument response as a function of the burst charge (the total electric charge of the protons in the burst shot onto the tungsten target) permitted to assess for each device the dose underestimation due to the time structure of the radiation field. The personal neutron dosemeters were exposed on a standard PMMA slab phantom and the response linearity was evaluated.

  1. AREAL test facility for advanced accelerator and radiation source concepts

    NASA Astrophysics Data System (ADS)

    Tsakanov, V. M.; Amatuni, G. A.; Amirkhanyan, Z. G.; Aslyan, L. V.; Avagyan, V. Sh.; Danielyan, V. A.; Davtyan, H. D.; Dekhtiarov, V. S.; Gevorgyan, K. L.; Ghazaryan, N. G.; Grigoryan, B. A.; Grigoryan, A. H.; Hakobyan, L. S.; Haroutiunian, S. G.; Ivanyan, M. I.; Khachatryan, V. G.; Laziev, E. M.; Manukyan, P. S.; Margaryan, I. N.; Markosyan, T. M.; Martirosyan, N. V.; Mehrabyan, Sh. A.; Mkrtchyan, T. H.; Muradyan, L. Kh.; Nikogosyan, G. H.; Petrosyan, V. H.; Sahakyan, V. V.; Sargsyan, A. A.; Simonyan, A. S.; Toneyan, H. A.; Tsakanian, A. V.; Vardanyan, T. L.; Vardanyan, A. S.; Yeremyan, A. S.; Zakaryan, S. V.; Zanyan, G. S.

    2016-09-01

    Advanced Research Electron Accelerator Laboratory (AREAL) is a 50 MeV electron linear accelerator project with a laser driven RF gun being constructed at the CANDLE Synchrotron Research Institute. In addition to applications in life and materials sciences, the project aims as a test facility for advanced accelerator and radiation source concepts. In this paper, the AREAL RF photoinjector performance, the facility design considerations and its highlights in the fields of free electron laser, the study of new high frequency accelerating structures, the beam microbunching and wakefield acceleration concepts are presented.

  2. The Dosimetric Parameters Investigation of the Pulsed X-ray and Gamma Radiation Sources

    NASA Astrophysics Data System (ADS)

    Stuchebrov, S. G.; Miloichikova, I. A.; Shilova, X. O.

    2016-01-01

    The most common type of radiation used for diagnostic purposes are X-rays. However, X-rays methods have limitations related to the radiation dose for the biological objects. It is known that the use of the pulsed emitting source synchronized with the detection equipment for internal density visualization of objects significant reduces the radiation dose to the object. In the article the analysis of the suitability of the different dosimetric equipment for the radiation dose estimation of the pulsed emitting sources is carried out. The approbation results on the pulsed X-ray generator RAP-160-5 of the dosimetry systems workability with the pulse radiation and its operation range are presented. The results of the dose field investigation of the portable betatron OB-4 are demonstrated. The depth dose distribution in the air, lead and water of the pulsed bremsstrahlung generated by betatron are shown.

  3. Certain considerations in aperture synthesis of ultrawideband/short-pulse radiation

    NASA Astrophysics Data System (ADS)

    Heyman, Ehud; Melamed, Timor

    1994-04-01

    We consider certain characteristics of the radiation from collimated, ultrawideband short-pulse aperture distributions. It is shown that an efficient radiation must account for the multifrequency nature of the field. Two alternative schemes for wideband aperture synthesis of an impulse-like radiation pattern are examined. The first, entitled the 'iso-width aperture,' utilizes only temporal shaping of the excitation pulse. In the other, the 'iso-diffracting aperture,' we suggest source shaping in space-time so that all the frequency components in the field have the same collimation distance. The 'iso-diffracting' scheme yields higher directivity and more efficient pulsed radiation. Explicit examples for the pulsed source distribution and for the pulsed radiation patterns are presented, parametrized, and contrasted.

  4. Radiation shielding for the Fermilab Vertical Cavity Test Facility

    SciTech Connect

    Ginsburg, Camille; Rakhno, Igor; /Fermilab

    2010-03-01

    The results of radiation shielding studies for the vertical test cryostat VTS1 at Fermilab performed with the codes FISHPACT and MARS15 are presented and discussed. The analysis is focused on operations with two RF cavities in the cryostat. The vertical cavity test facility (VCTF) for superconducting RF cavities in Industrial Building 1 at Fermilab has been in operation since 2007. The facility currently consists of a single vertical test cryostat VTS1. Radiation shielding for VTS1 was designed for operations with single 9-cell 1.3 GHz cavities, and the shielding calculations were performed using a simplified model of field emission as the radiation source. The operations are proposed to be extended in such a way that two RF cavities will be in VTS1 at a time, one above the other, with tests for each cavity performed sequentially. In such a case the radiation emitted during the tests from the lower cavity can, in part, bypass the initially designed shielding which can lead to a higher dose in the building. Space for additional shielding, either internal or external to VTS1, is limited. Therefore, a re-evaluation of the radiation shielding was performed. An essential part of the present analysis is in using realistic models for cavity geometry and spatial, angular and energy distributions of field-emitted electrons inside the cavities. The calculations were performed with the computer codes FISHPACT and MARS15.

  5. Development of a cryogenic EOS capability for the Z Pulsed Radiation Source: Goals and accomplishments of FY97 LDRD project

    SciTech Connect

    Hanson, D.L.; Johnston, R.R.; Asay, J.R.

    1998-03-01

    Experimental cryogenic capabilities are essential for the study of ICF high-gain target and weapons effects issues involving dynamic materials response at low temperatures. This report describes progress during the period 2/97-11/97 on the FY97 LDRD project ``Cryogenic EOS Capabilities on Pulsed Radiation Sources (Z Pinch)``. The goal of this project is the development of a general purpose cryogenic target system for precision EOS and shock physics measurements at liquid helium temperatures on the Z accelerator Z-pinch pulsed radiation source. Activity during the FY97 LDRD phase of this project has focused on development of a conceptual design for the cryogenic target system based on consideration of physics, operational, and safety issues, design and fabrication of principal system components, construction and instrumentation of a cryogenic test facility for off-line thermal and optical testing at liquid helium temperatures, initial thermal testing of a cryogenic target assembly, and the design of a cryogenic system interface to the Z pulsed radiation source facility. The authors discuss these accomplishments as well as elements of the project that require further work.

  6. Proton and heavy ion acceleration facilities for space radiation research

    NASA Technical Reports Server (NTRS)

    Miller, Jack

    2003-01-01

    The particles and energies commonly used for medium energy nuclear physics and heavy charged particle radiobiology and radiotherapy at particle accelerators are in the charge and energy range of greatest interest for space radiation health. In this article we survey some of the particle accelerator facilities in the United States and around the world that are being used for space radiation health and related research, and illustrate some of their capabilities with discussions of selected accelerator experiments applicable to the human exploration of space.

  7. Proton and heavy ion acceleration facilities for space radiation research.

    PubMed

    Miller, Jack

    2003-06-01

    The particles and energies commonly used for medium energy nuclear physics and heavy charged particle radiobiology and radiotherapy at particle accelerators are in the charge and energy range of greatest interest for space radiation health. In this article we survey some of the particle accelerator facilities in the United States and around the world that are being used for space radiation health and related research, and illustrate some of their capabilities with discussions of selected accelerator experiments applicable to the human exploration of space. PMID:12959128

  8. POST-SHOT RADIATION ENVIRONMENT FOLLOWING LOW-YIELD SHOTS INSIDE THE NATIONAL IGNITION FACILITY

    SciTech Connect

    Sitaraman, S; Brereton, S; Dauffy, L; Hall, J; Hansen, L; Khater, H; Kim, S; Pohl, B; Verbeke, J

    2010-10-29

    A detailed model of the Target Bay (TB) at the National Ignition Facility (NIF) has been developed to estimate the post-shot radiation environment inside the facility. The model includes large number of structures and diagnostic instruments present inside the TB. These structures and instruments are activated by the few nanosecond pulse of neutrons generated during a shot and the resultant gamma dose rates are estimated at various decay times following the shot. The results presented in this paper are based on a low-yield D-T shot of 10{sup 16} neutrons. General environment dose rates drop to below 3 mrem/h within three hours following a shot with higher dose rates observed at contact with some of the components. Dose rate maps of the different TB levels were generated to aid in estimating worker stay-out times following a shot before entry is permitted into the TB.

  9. Smoke detector with a radiation source operated in a pulse-like or intermittent mode

    SciTech Connect

    Muggli, J.; Guttinger, H.

    1985-03-19

    A smoke detector contains a pulse-operated radiation source and a radiation receiver arranged externally of the region directly irradiated by the radiation source. The radiation receiver, in the presence of smoke in the radiation region, is impinged by scattered radiation and delivers output pulses. There is provided an evaluation circuit which generates a blocking pulse, and which inputs a resetting signal to a counter device in consequence of the difference of the blocking pulse and output pulse of the radiation receiver. The counter or counting device, in the absence of a resetting signal, is switched further and upon reaching a predetermined counter state triggers an alarm signal. High-frequency electrical disturbances which arise, as long as the radiation source delivers radiation pulses, at most can generate an additional resetting signal for the counter, so that the integrity of the smoke detector against triggering of false alarms is enhanced. If there is connected in parallel to the radiation receiver a NTC-resistor, then there is obtained a smoke detector which responds to a further combustion criterion (temperature).

  10. Target diagnostics for commissioning the AWE HELEN Laser Facility 100 TW chirped pulse amplification beam

    NASA Astrophysics Data System (ADS)

    Eagleton, R. T.; Clark, E. L.; Davies, H. M.; Edwards, R. D.; Gales, S.; Girling, M. T.; Hoarty, D. J.; Hopps, N. W.; James, S. F.; Kopec, M. F.; Nolan, J. R.; Ryder, K.

    2006-10-01

    The capability of the HELEN laser at the Atomic Weapons Establishment Aldermaston has been enhanced by the addition of a short-pulse laser beam to augment the twin opposing nanosecond time scale beams. The short-pulse beam utilizes the chirped pulse amplification (CPA) technique and is capable of delivering up to 60J on target in a 500fs pulse, around 100TW, at the fundamental laser wavelength of 1.054μm. During the commissioning phase a number of diagnostic systems have been fielded, these include: x-ray pinhole imaging of the laser heated spot, charged particle time of flight, thermoluminescent dosimeter array, calibrated radiochromic film, and CR39 nuclear track detector. These diagnostic systems have been used to verify the performance of the CPA beam to achieve a focused intensity of around 1019Wcm-2 and to underwrite the facility radiological safety system.

  11. Atmospheric Radiation Measurement Program Facilities Newsletter - September 1999

    SciTech Connect

    Holdridge, D. J., ed

    1999-09-27

    The Atmospheric Radiation Measurement Program September 1999 Facilities Newsletter discusses the several Intensive Observation Periods (IOPs) that the ARM SGP CART site will host in the near future. Two projects of note are the International Pyrgeometer Intercomparison and the Fall Single Column Model (SCM)/Nocturnal Boundary Layer (NBL) IOP. Both projects will bring many US and international scientists to the SGP CART site to participate in atmospheric research.

  12. The Neutral Beam Test Facility and Radiation Effects Facility at Brookhaven National Laboratory

    SciTech Connect

    McKenzie-Wilson, R.B.

    1990-01-01

    As part of the Strategic Defense Initiative (SDI) Brookhaven National Laboratory (BNL) has constructed a Neutral Beam Test Facility (NBTF) and a Radiation Effects Facility (REF). These two facilities use the surplus capacity of the 200-MeV Linac injector for the Alternating Gradient Synchrotron (AGS). The REF can be used to simulate radiation damage effects in space from both natural and man made radiation sources. The H{sup {minus}} beam energy, current and dimensions can be varied over a wide range leading to a broad field of application. The NBTF has been designed to carry out high precision experiments and contains an absolute reference target system for the on-line calibration of measurements carried out in the experimental hall. The H{sup {minus}} beam energy, current and dimensions can also be varied over a wide range but with tradeoffs depending on the required accuracy. Both facilities are fully operational and will be described together with details of the associated experimental programs.

  13. Operation of an industrial radiation processing facility in Mexico

    NASA Astrophysics Data System (ADS)

    Torres C., Gilberto

    A 10 years old JS-6500 industrial Cobalt 60 irradiator was installed in 1980 at the ININ Nuclear Center in Mexico with 960 kGy. The facility was commissioning in August with some minor changes with respect to the original AECL design, in order to give services to different industries and also to do research in several fields. During that year promotional activities were done to increase interest from industry in the use of radiation processing. In 1981, an interruption due to pool's leakage and its reparation, put the facility out of operation. During the next three years the demand increases but never reach more than 50% if the capacity. In that time, the potential users did not show confidence in the process, even knowing that health authorities approved with no restrictions radiation sterilization. Actually, there are 34 different companies irradiating 48 different products. Even those within the same grouping, require different minimum and maximum radiation doses, so the facility has been operated combining products and valumes. The experiences are presented in this paper. Also, maintenance of the irradiator is discussed and some modifications to the original programme have been done due to the necessity to use local spare parts instead of imported ones.

  14. Design of Power Supplies for the Pulsed High Magnetic Field Facility at HUST

    NASA Astrophysics Data System (ADS)

    Ding, Hongfa; Ding, Tonghai; Jiang, Chengxi; Xu, Yun; Xiao, Houxiu; Li, Liang; Duan, Xianzhong; Pan, Yuan

    2010-04-01

    Two types of pulsed power supply, a modular 12 MJ/25 kV capacitor bank and a 100 MVA flywheel pulsed generator, are under construction for the pulsed high magnetic field facility at the Huazhong University of Science and Technology (HUST) in Wuhan, China. The capacitor bank consists of 11 independent 1 MJ modules with a short circuit current of 40 kA each and 2 independent 0.5 MJ modules for 50 kA each. The bank is used to energize coils for magnetic fields in the 50-80 T range with pulse duration from 15 to 200 ms. The pulsed flywheel-alternator is used to energize a 50 T/100 ms long-pulse magnet via two 12-pulse power converter modules. Each converter module is designed to operate in the 95 to 66 Hz frequency operation range of the generator and can provide a no-load voltage of 4.6 kV and a full-load voltage of 3.4 kV at the rated current of 20 kA. In this paper the design of these two types of power supply is presented.

  15. Generation of two-color ultra-short radiation pulses from two electron bunches and a chirped seeded free-electron laser

    NASA Astrophysics Data System (ADS)

    Feng, Chao; Wang, Zhen; Wang, Xingtao; Huang, Dazhang

    2016-01-01

    In this paper we describe a new method for the realization of two-color femtosecond radiation pulses in a seeded free-electron laser (FEL). The two-color pulses are obtained from two electron bunches and a chirped seeding laser. Compared to the previous methods based on seeded FELs, our method has the advantages of producing two-color FEL pulses with more flexible tunability both in the pulse durations and separations. Numerical simulations for the Dalian Coherent Light Source confirm that femtosecond XUV pulses with variable pulse durations and time delay can be directly generated from a chirped seed laser at 250 nm by using this technique. We also show the possibility of performing a proof-of-principle experiment of this technique based on the Shanghai Deep-Ultraviolet FEL facility.

  16. Method and apparatus for providing pulse pile-up correction in charge quantizing radiation detection systems

    DOEpatents

    Britton, Jr., Charles L.; Wintenberg, Alan L.

    1993-01-01

    A radiation detection method and system for continuously correcting the quantization of detected charge during pulse pile-up conditions. Charge pulses from a radiation detector responsive to the energy of detected radiation events are converted to voltage pulses of predetermined shape whose peak amplitudes are proportional to the quantity of charge of each corresponding detected event by means of a charge-sensitive preamplifier. These peak amplitudes are sampled and stored sequentially in accordance with their respective times of occurrence. Based on the stored peak amplitudes and times of occurrence, a correction factor is generated which represents the fraction of a previous pulses influence on a preceding pulse peak amplitude. This correction factor is subtracted from the following pulse amplitude in a summing amplifier whose output then represents the corrected charge quantity measurement.

  17. Considerations concerning the use of counting active personal dosimeters in pulsed fields of ionising radiation.

    PubMed

    Ambrosi, Peter; Borowski, Markus; Iwatschenko, Michael

    2010-06-01

    Active personal electronic dosimeters (APDs) exhibit limitations in pulsed radiation fields, which cannot be overcome without the use of new detection technology. As an interim solution, this paper proposes a method by which some conventional dosimeters can be operated in a way such that, based on the basic knowledge about the pulsed radiation field, any dosimetric failure of the dosimeter is signalised by the instrument itself. This method is not applicable to all combinations of APD and pulsed radiation field. The necessary requirements for the APD and for the parameters of the pulsed radiation field are given in the paper. Up to now, all such requirements for APDs have not been tested or verified in a type test. The suitability of the method is verified for the use of one APD used in two clinical pulsed fields. PMID:20083488

  18. Status and Planned Experiments of the Hiradmat Pulsed Beam Material Test Facility at CERN SPS

    SciTech Connect

    Charitonidis, Nikolaos; Efthymiopoulos, Ilias; Fabich, Adrian; Meddahi, Malika; Gianfelice-Wendt, Eliana

    2015-06-01

    HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a maximum number of 1016 protons per year, in order to limit the activation of the irradiated samples to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and go through examples of upcoming experiments scheduled in the beam period 2015/2016.

  19. Early test facilities and analytic methods for radiation shielding: Proceedings

    SciTech Connect

    Ingersoll, D.T. ); Ingersoll, J.K. )

    1992-11-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting. The meeting is of special significance since it commemorates the fiftieth anniversary of the first controlled nuclear chain reaction. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting. The paper titles are good indicators of their content and are: (1) The origin of radiation shielding research: The Oak Ridge experience, (2) Shielding research at the hanford site, (3) Aircraft shielding experiments at General Dynamics Fort Worth, 1950-1962, (4) Where have the neutrons gone , a history of the tower shielding facility, (5) History and evolution of buildup factors, (6) Early shielding research at Bettis atomic power laboratory, (7) UK reactor shielding: then and now, (8) A very personal view of the development of radiation shielding theory.

  20. System for determining the type of nuclear radiation from detector output pulse shape

    DOEpatents

    Miller, W.H.; Berliner, R.R.

    1994-09-13

    A radiation detection system determines the type of nuclear radiation received in a detector by producing a correlation value representative of the statistical cross correlation between the shape of the detector signal and pulse shape data previously stored in memory and characteristic of respective types of radiation. The correlation value is indicative of the type of radiation. The energy of the radiation is determined from the detector signal and is used to produce a spectrum of radiation energies according to radiation type for indicating the nature of the material producing the radiation. 2 figs.

  1. System for determining the type of nuclear radiation from detector output pulse shape

    DOEpatents

    Miller, William H.; Berliner, Ronald R.

    1994-01-01

    A radiation detection system determines the type of nuclear radiation received in a detector by producing a correlation value representative of the statistical cross correlation between the shape of the detector signal and pulse shape data previously stored in memory and characteristic of respective types of radiation. The correlation value is indicative of the type of radiation. The energy of the radiation is determined from the detector signal and is used to produce a spectrum of radiation energies according to radiation type for indicating the nature of the material producing the radiation.

  2. A new digital pulse power supply in heavy ion research facility in Lanzhou

    NASA Astrophysics Data System (ADS)

    Wang, Rongkun; Chen, Youxin; Huang, Yuzhen; Gao, Daqing; Zhou, Zhongzu; Yan, Huaihai; Zhao, Jiang; Shi, Chunfeng; Wu, Fengjun; Yan, Hongbin; Xia, Jiawen; Yuan, Youjin

    2013-11-01

    To meet the increasing requirements of the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), a new digital pulse power supply, which employs multi-level converter, was designed. This power supply was applied with a multi H-bridge converters series-parallel connection topology. A new control model named digital power supply regulator system (DPSRS) was proposed, and a pulse power supply prototype based on DPSRS has been built and tested. The experimental results indicate that tracking error and ripple current meet the requirements of this design. The achievement of prototype provides a perfect model for HIRFL-CSR power supply system.

  3. CONTROL OF LASER RADIATION PARAMETERS: Direct amplification of picosecond pulses in neodymium glass with a power density above 100 GW cm-2

    NASA Astrophysics Data System (ADS)

    Ivanov, Vladimir V.; Kutsenko, A. V.; Matsveiko, A. A.; Mikhailov, Yu A.; Popov, A. I.; Sklizkov, G. V.; Starodub, Aleksandr N.; Chekmarev, Alexander M.

    2003-09-01

    A scheme for amplification of ultrashort laser pulses is studied, which is used in experiments on symmetrisation of ablation pressure with the help of a prepulse upon acceleration of foils by laser radiation of high brightness. The possibility of direct amplification of short pulses before their expansion in order to increase the energy contrast is considered. In experiments performed on the PICO facility, the amplification of a 10-ps pulse with a power density exceeding 100 GW cm-2 is demonstrated with the gain equal to 1.2 and the inversion drop above 30 %.

  4. Circularly polarized carrier-envelope-phase stable attosecond pulse generation based on coherent undulator radiation.

    PubMed

    Tóth, Gy; Tibai, Z; Nagy-Csiha, Zs; Márton, Zs; Almási, G; Hebling, J

    2015-09-15

    In this Letter, we present a new method for generation of circularly polarized attosecond pulses. According to our calculations, shape-controlled, carrier-envelope-phase stable pulses of several hundred nanojoule energy could be produced by exploitation of the coherent undulator radiation of an electron bunch. Our calculations are based on an existing particle accelerator system (FLASH II in DESY, Germany). We investigated the energy dependence of the attosecond pulses on the energy of electrons and the parameters of the radiator undulator, which generate the electromagnetic radiation. PMID:26371925

  5. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

    NASA Astrophysics Data System (ADS)

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M.; Kong, Wei

    2015-08-01

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He2+ and He4+, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl4 doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He)nC+, (He)nCl+, and (He)nCCl+. Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  6. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

    SciTech Connect

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M.; Kong, Wei

    2015-08-15

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He{sub 2}{sup +} and He{sub 4}{sup +}, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl{sub 4} doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He){sub n}C{sup +}, (He){sub n}Cl{sup +}, and (He){sub n}CCl{sup +}. Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  7. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams.

    PubMed

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M; Kong, Wei

    2015-08-01

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He2(+) and He4(+), which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl4 doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He)(n)C(+), (He)(n)Cl(+), and (He)(n)CCl(+). Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets. PMID:26329210

  8. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2007

    SciTech Connect

    LR Roeder

    2007-12-01

    This annual report describes the purpose and structure of the program, and presents key accomplishments in 2007. Notable achievements include: • Successful review of the ACRF as a user facility by the DOE Biological and Environmental Research Advisory Committee. The subcommittee reinforced the importance of the scientific impacts of this facility, and its value for the international research community. • Leadership of the Cloud Land Surface Interaction Campaign. This multi-agency, interdisciplinary field campaign involved enhanced surface instrumentation at the ACRF Southern Great Plains site and, in concert with the Cumulus Humilis Aerosol Processing Study sponsored by the DOE Atmospheric Science Program, coordination of nine aircraft through the ARM Aerial Vehicles Program. • Successful deployment of the ARM Mobile Facility in Germany, including hosting nearly a dozen guest instruments and drawing almost 5000 visitors to the site. • Key advancements in the representation of radiative transfer in weather forecast models from the European Centre for Medium-Range Weather Forecasts. • Development of several new enhanced data sets, ranging from best estimate surface radiation measurements from multiple sensors at all ACRF sites to the extension of time-height cloud occurrence profiles to Niamey, Niger, Africa. • Publication of three research papers in a single issue (February 2007) of the Bulletin of the American Meteorological Society.

  9. Calibration facilities for borehole and surface environmental radiation measurements

    SciTech Connect

    Stromswold, D.C.

    1994-04-01

    Measuring radiation from contaminated soil and buildings is important in the cleanup of land areas and facilities. It provides the means for quantifying the amount of contamination and assessing the success of efforts to restore areas to acceptable conditions for public use. Instruments that measure in situ radiation from natural or radiochemically-contaminated earth formations must be calibrated in appropriate facilities to provide quantitative assessments of concentrations of radionuclides. For instruments that are inserted into boreholes, these calibration facilities are typically special models having holes for probe insertion and having sufficient size to appear radiometrically ``infinite`` in extent. The US Department of Energy (DOE) has such models at Hanford, Washington, and Grand Junction, Colorado. They are concrete cylinders having a central borehole and containing known, enhanced amounts of K, U, and Th for spectral gamma-ray measurements. Additional models contain U for calibrating neutron probes for fissile materials and total-count gamma-ray probes. Models for calibrating neutron probes for moisture measurements in unsaturated formations exist for steel-cased boreholes at Hanford and for uncased boreholes at the DOE`s Nevada Test Site. Large surface pads are available at Grand Junction for portable, vehicle-mounted, or airplane-mounted spectral gamma-ray detectors.

  10. Design concepts for a pulse power test facility to simulate EMP surges. Part II. Slow pulses

    SciTech Connect

    Dethlefsen, R.

    1985-10-01

    The work described in this report was sponsored by the Division of Electric Energy Systems (EES) of the US Department of Energy (DOE) through a subcontract with the Power Systems Technology Program at the Oak Ridge National Laboratory (ORNL). The work deals with the effect of high altitude nuclear bursts on electric power systems. In addition to fast voltage transients, slow, quasi-dc currents are also induced into extended power systems with grounded neutral connections. Similar phenomena at lower magnitude are generated by solar induced electromagnetic pulses (EMP). These have caused power outages, related to solar storms, at northern latitudes. The applicable utility experience is reviewed in order to formulate an optimum approach to future testing. From a wide variety of options two pulser designs were selected as most practical, a transformer-rectifier power supply, and a lead acid battery pulser. both can be mounted on a trailer as required for field testing on utility systems. The battery system results in the least cost. Testing on power systems requires that the dc pulser pass high values of alternating current, resulting from neutral imbalance or from potential fault currents. Batteries have a high ability to pass alternating currents. Most other pulser options must be protected by an ac bypass in the form of an expensive capacitor bank. 8D truck batteries can meet the original specification of 1 kA test current. Improved batteries for higher discharge currents are available.

  11. Contribution for Iron Vapor and Radiation Distribution Affected by Current Frequency of Pulsed Arc

    NASA Astrophysics Data System (ADS)

    Shimokura, Takuya; Mori, Yusuke; Iwao, Toru; Yumoto, Motoshige

    Pulsed GTA welding has been used for improvement of stability, weld speed, and heat input control. However, the temperature and radiation power of the pulsed arc have not been elucidated. Furthermore, arc contamination by metal vapor changes the arc characteristics, e.g. by increasing radiation power. In this case, the metal vapor in pulsed GTA welding changes the distribution of temperature and radiation power as a function of time. This paper presents the relation between metal vapor and radiation power at different pulse frequencies. We calculate the Fe vapor distribution of the pulsed current. Results show that the Fe vapor is transported at fast arc velocity during the peak current period. During the base current period, the Fe vapor concentration is low and distribution is diffuse. The transition of Fe vapor distribution does not follow the pulsed current; the radiation power density distribution differs for high frequencies and low frequencies. In addition, the Fe vapor and radiation distribution are affected by the pulsed arc current frequency.

  12. Focal spot measurement in ultra-intense ultra-short pulse laser facility

    NASA Astrophysics Data System (ADS)

    Liu, Lanqin; Peng, Hansheng; Zhou, Kainan; Wang, Xiaodong; Wang, Xiao; Zeng, Xiaoming; Zhu, Qihua; Huang, Xiaojun; Wei, Xiaofeng; Ren, Huan

    2005-06-01

    A peak power of 286-TW Ti:sapphire laser facility referred to as SILEX-I was successfully built at China Academy of Engineering Physics, for a pulse duration of 30 fs in a three-stage Ti:sapphire amplifier chain based on chirped-pulse amplification. The beam have a wavefront distortion of 0.63μm PV and 0.09μm RMS, and the focal spot with an f/2.2 OAP is 5.7μm, to our knowledge, this is the best far field obtained for high-power ultra-short pulse laser systems with no deformable mirror wavefront correction. The peak focused intensity of ~1021W /cm2 were expected.

  13. Atmospheric Radiation Measurement Program facilities newsletter, February 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-03-08

    This newsletter consists of the following: (1) ARM Science Team Meeting Scheduled--The 11th Annual ARM Science Team meeting is scheduled for March 19-23, 2001, in Atlanta, Georgia. Members of the science team will exchange research results achieved by using ARM data. The science team is composed of working groups that investigate four topics: instantaneous radiative flux, cloud parameterizations and modeling, cloud properties, and aerosols. The annual meeting brings together the science team's 150 members to discuss issues related to ARM and its research. The members represent universities, government laboratories and research facilities, and independent research companies. (2) Communications to Extended Facilities Upgraded--New communications equipment has been installed at all of the SGP extended facilities. Shelters were installed to house the new equipment used to transfer data from instruments via the Internet to the site data system at the central facility. This upgrade has improved data availability from the extended facilities to 100% and reduced telephone costs greatly. (3) SGP Goes ''Buggy''--Steve Sekelsky, a researcher from the University of Massachusetts, is planning to bring a 95-GHz radar to the SGP central facility for deployment in March-October 2001. The radar will help to identify signals due to insects flying in the air. The ARM millimeter cloud radar, which operates at 35 GHz, is sensitive to such insect interference. Testing will also be performed by using a second 35-GHz radar with a polarized radar beam, which can differentiate signals from insects versus cloud droplets. (4) Winter Fog--Fog can add to hazards already associated with winter weather. Common types of fog formation include advection, radiation, and steam. Advection fog: An advection fog is a dense fog that forms when a warm, moist air mass moves into an area with cooler ground below. For example, fog can form in winter when warmer, water-saturated air from the south (associated

  14. Neutron Radiography Facility at IBR-2 High Flux Pulsed Reactor: First Results

    NASA Astrophysics Data System (ADS)

    Kozlenko, D. P.; Kichanov, S. E.; Lukin, E. V.; Rutkauskas, A. V.; Bokuchava, G. D.; Savenko, B. N.; Pakhnevich, A. V.; Rozanov, A. Yu.

    A neutron radiography and tomography facilityhave been developed recently at the IBR-2 high flux pulsed reactor. The facility is operated with the CCD-camera based detector having maximal field of view of 20x20 cm, and the L/D ratio can be varied in the range 200 - 2000. The first results of the radiography and tomography experiments with industrial materials and products, paleontological and geophysical objects, meteorites, are presented.

  15. Full circuit calculation for electromagnetic pulse transmission in a high current facility

    NASA Astrophysics Data System (ADS)

    Zou, Wenkang; Guo, Fan; Chen, Lin; Song, Shengyi; Wang, Meng; Xie, Weiping; Deng, Jianjun

    2014-11-01

    We describe herein for the first time a full circuit model for electromagnetic pulse transmission in the Primary Test Stand (PTS)—the first TW class pulsed power driver in China. The PTS is designed to generate 8-10 MA current into a z -pinch load in nearly 90 ns rise time for inertial confinement fusion and other high energy density physics research. The PTS facility has four conical magnetic insulation transmission lines, in which electron current loss exists during the establishment of magnetic insulation. At the same time, equivalent resistance of switches and equivalent inductance of pinch changes with time. However, none of these models are included in a commercially developed circuit code so far. Therefore, in order to characterize the electromagnetic transmission process in the PTS, a full circuit model, in which switch resistance, magnetic insulation transmission line current loss and a time-dependent load can be taken into account, was developed. Circuit topology and an equivalent circuit model of the facility were introduced. Pulse transmission calculation of shot 0057 was demonstrated with the corresponding code FAST (full-circuit analysis and simulation tool) by setting controllable parameters the same as in the experiment. Preliminary full circuit simulation results for electromagnetic pulse transmission to the load are presented. Although divergences exist between calculated and experimentally obtained waveforms before the vacuum section, consistency with load current is satisfactory, especially at the rising edge.

  16. Pulsed laser facilities operating from UV to IR at the Gas Laser Lab of the Lebedev Institute

    NASA Astrophysics Data System (ADS)

    Ionin, Andrei; Kholin, Igor; Vasil'Ev, Boris; Zvorykin, Vladimir

    2003-05-01

    Pulsed laser facilities developed at the Gas Lasers Lab of the Lebedev Physics Institute and their applications for different laser-matter interactions are discussed. The lasers operating from UV to mid-IR spectral region are as follows: e-beam pumped KrF laser (λ= 0.248 μm) with output energy 100 J; e-beam sustained discharge CO2(10.6 μm) and fundamental band CO (5-6 μm) lasers with output energy up to ~1 kJ; overtone CO laser (2.5-4.2 μm) with output energy ~ 50 J and N2O laser (10.9 μm) with output energy of 100 J; optically pumped NH3 laser (11-14 μm). Special attention is paid to an e-beam sustained discharge Ar-Xe laser (1.73 μm ~ 100 J) as a potential candidate for a laser-propulsion facility. The high energy laser facilities are used for interaction of laser radiation with polymer materials, metals, graphite, rocks, etc.

  17. Deconvolving the temporal response of photoelectric x-ray detectors for the diagnosis of pulsed radiations

    NASA Astrophysics Data System (ADS)

    Zou, Shiyang; Song, Peng; Guo, Liang; Pei, Wenbing

    2013-09-01

    Based on the conjugate gradient method, a simple algorithm is presented for deconvolving the temporal response of photoelectric x-ray detectors (XRDs) to reconstruct the resolved time-dependent x-ray fluxes. With this algorithm, we have studied the impact of temporal response of XRD on the radiation diagnosis of hohlraum heated by a short intense laser pulse. It is found that the limiting temporal response of XRD not only postpones the rising edge and peak position of x-ray pulses but also smoothes the possible fluctuations of radiation fluxes. Without a proper consideration of the temporal response of XRD, the measured radiation flux can be largely misinterpreted for radiation pulses of a hohlraum heated by short or shaped laser pulses.

  18. Low-temperature radiation cracking of heavy oil under continuous and pulse electron irradiation

    NASA Astrophysics Data System (ADS)

    Zaikin, Yuriy A.

    2016-05-01

    The dependence of the chain reaction parameters on the conditions of pulse and continuous electron irradiation is analyzed for the case of low-temperature radiation cracking of heavy oils. The specificity of kinetics and yields of light products after radiation cracking are considered in the cases of continuous and pulse irradiation. Theoretical calculations are compared with experimental data on electron irradiation of heavy oil in different conditions.

  19. High-resolution pulsed-field ionization photoelectron spectroscopy using multi-bunch synchrotron radiation

    SciTech Connect

    Hsu, C.W.; Evans, M.; Ng, C.Y.; Heimann, P.

    1997-04-01

    BL9.0.2.2 is the newly constructed experimental End Station 2 at the Chemical Dynamics Beamline 9.0.2 of the Advanced Light Source (ALS). It is dedicated to the high resolution photoionization study of molecules of interest to atmospheric and combustion chemistry. This End Station is equipped with a high resolution scanning monochromator, which has been demonstrated to have a world record resolution of E/{delta}E=70,000. Taking the advantage of the high resolution ALS light, the authors have improved the energy resolution in threshold photoelectron spectroscopy (TPES) to 0.8 meV. The TPES is a popular technique for photoionization experiments at all synchrotron radiation facilities due to its high energy resolution as compared to that of traditional photoelectron spectroscopy (PES). TPES achieves higher energy resolution by preferentially detecting near zero kinetic energy photoelectrons resulting from threshold photoionization. However, the spectra obtained from the TPES technique generally are complicated by the simultaneous detection of electrons with nonzero kinetic energy, which are not fully discriminated against. On the other hand, the spectra obtained from pulsed field ionization photoelectron spectroscopy (PFI-PES) are completely free of the contamination from kinetic electrons. The PFI-PE technique basically involves the detection of the photoelectrons from field ionization of the very high-n Rydberg states, a few cm{sup {minus}1} below the ionization energy (IE), by applying a delayed pulsed electric field. Within a delay of a few microseconds, all the prompt electrons formed from direct ionization will escape from the photoionization region and will not be collected. The authors have recently overcome problems with energy resolution of an electron time-of-flight technique, and incorporated the PFI-PE technique with multi-bunch VUV synchrotron radiation.

  20. Cryogenic capability for equation-of-state measurements on the Sandia Z pulsed radiation source

    SciTech Connect

    Hanson, D.L.; Johnston, R.R.; Asay, J.R.

    1998-02-01

    Experimental cryogenic capabilities are essential for the study of ICF high-gain target and weapons effects issues involving dynamic materials response at low temperatures. The authors are developing a general purpose cryogenic target system for precision radiation driven EOS and shock physics experiments at liquid helium temperatures on the Sandia Z pulsed radiation source. Cryogenic sample cooling in the range of 6--30 K is provided by a liquid helium cryostat and an active temperature control system. The cryogenic target assembly is capable of condensing liquid deuterium samples from the gas phase at about 20 K, as well as cooling solid samples such as beryllium and CH ablators for ICF. The target assembly will also include the capability to use various shock diagnostics, such as VISAR interferometry and fiber-optic-coupled shock breakout diagnostics. They are characterizing the thermal and optical performance of the system components in an off-line cryogenic test facility and have designed an interface to introduce the cryogenic transfer lines, gas lines, and sensor cables into the Z vacuum section. Survivability of high-value cryogenic components in the destructive post-implosion environment of Z is a major issue driving the design of this cryogenic target system.

  1. K{sub α} and bremsstrahlung x-ray radiation backlighter sources from short pulse laser driven silver targets as a function of laser pre-pulse energy

    SciTech Connect

    Jarrott, L. C.; Mariscal, D.; McGuffey, C.; Beg, F. N.; Kemp, A. J.; Divol, L.; Chen, C.; Hey, D.; Maddox, B.; Hawreliak, J.; Park, H.-S.; Remington, B.; MacPhee, A.; Westover, B.; Suggit, M.; Wei, M. S.

    2014-03-15

    Measurements of silver K-shell and bremsstrahlung emission from thin-foil laser targets as a function of laser prepulse energy are presented. The silver targets were chosen as a potential 22 keV backlighter source for the National Ignition Facility Experiments. The targets were irradiated by the Titan laser with an intensity of 8 × 10{sup 17} W/cm{sup 2} with 40 ps pulse length. A secondary nanosecond timescale laser pulse with controlled, variable energy was used to emulate the laser prepulse. Results show a decrease in both K{sub α} and bremsstrahlung yield with increasing artificial prepulse. Radiation hydrodynamic modeling of the prepulse interaction determined that the preplasma and intact target fraction were different in the three prepulse energies investigated. Interaction of the short pulse laser with the resulting preplasma and target was then modeled using a particle-in-cell code PSC which explained the experimental results. The relevance of this work to future Advanced Radiographic Capability laser x-ray backlighter sources is discussed.

  2. Development of a pulsed cable test facility for superconducting ohmic heating coils

    SciTech Connect

    Kim, S.H.; Smith, R.P.; Kustom, R.L.; Praeg, W.F.; Krieger, C.I.

    1980-01-01

    This paper describes a Pulsed Cable Test Facility (PCTF) under development at Argonne National Laboratory (ANL). Its essential part is a pulsed superconducting split coil. The inner and outer diameters of the coil will be 45.1 cm and 88.3 cm, respectively, with an adjustable gap between the two halves of the coil. At a peak current of 11 kA, the coil will store an energy of 3.5 MJ and produce a magnetic field of 6.4 T. Using a 7 MW pulsed (2.9 MW rms) power supply, the PCTF coil will produce field change of 6 T/s. With the addition of a solid state switch to the system, dB/dt values of up to 24 T/s can be obtained. Pancake coils, wound with developmental cables, will be placed in the adjustable gap of the PCTF coil and be tested at up to 50 kA furnished by a separate power supply. The PCTF cryogenic facilities include a non-metallic cryostat and a helium liquefier.

  3. On the nature of the sources of hard pulse X-ray radiation

    NASA Technical Reports Server (NTRS)

    Shklovskiy, I. S.

    1978-01-01

    Besides the identified sources of cosmic pulse X-ray radiation with globular clusters NGC 6624, NGC 1851 and MXB 1730-335 several new identifications were made. The source in Norma was probably identified with globular cluster NGC 5927, the source in Aquila with globular cluster NGC 6838 (M71), and the source in Puppis with globular cluster NGC 2298. Gamma pulses discovered by the Vela satellites and X-ray pulses thoroughly measured by the SAS-3, Ariel-5, and ANS satellites are thought to be the same phenomenon. The sources of such a radiation must be some kind of peculiarity at the central part of globular clusters; it is most probably a massive black hole. The sources of hard pulse radiation which cannot be identified with globular clusters are considered to be a new kind of galactic object, invisible globular clusters, which are naked nuclei of globular clusters.

  4. Fluctuations of energy density of short-pulse optical radiation in the turbulent atmosphere.

    PubMed

    Banakh, V A; Smalikho, I N

    2014-09-22

    Fluctuations of energy density of short-pulse optical radiation in the turbulent atmosphere have been studied based on numerical solution of the parabolic wave equation for the complex spectral amplitude of the wave field by the split-step method. It has been shown that under conditions of strong optical turbulence, the relative variance of energy density fluctuations of pulsed radiation of femtosecond duration becomes much less than the relative variance of intensity fluctuations of continuous-wave radiation. The spatial structure of fluctuations of the energy density with a decrease of the pulse duration becomes more large-scale and homogeneous. For shorter pulses the maximal value of the probability density distribution of energy density fluctuations tends to the mean value of the energy density. PMID:25321700

  5. Single sub-50-attosecond pulse generation from chirp-compensated harmonic radiation using material dispersion

    SciTech Connect

    Kim, Kyung Taec; Kim, Chul Min; Umesh, G.; Nam, Chang Hee; Baik, Moon-Gu

    2004-05-01

    A method for obtaining a single sub-50-attosecond pulse using harmonic radiation is proposed. For the generation of broad harmonic radiation during a single half-optical cycle, atoms are driven by a femtosecond laser pulse with intensity above the saturation intensity for optical field ionization and hence experience a large nonadiabatic increase of the laser electric field between optical cycles. Although the chirped structure of the harmonic radiation imposes a limit on the minimum achievable pulse duration, we demonstrate that its positive chirp can be compensated by the negative group delay dispersion of an appropriately selected x-ray filter material, used also for the spectral selection, resulting in a single attosecond pulse with a duration less than 50 as.

  6. The effects of pulse duration on ablation pressure driven by laser radiation

    SciTech Connect

    Zhou, Lei; Li, Xiao-Ya Zhu, Wen-Jun; Wang, Jia-Xiang; Tang, Chang-Jian

    2015-03-28

    The effects of laser pulse duration on the ablation pressure induced by laser radiation are investigated using Al target. Numerical simulation results using one dimensional radiation hydro code for laser intensities from 5×10{sup 12}W/cm{sup 2} to 5×10{sup 13}W/cm{sup 2} and pulse durations from 0.5 ns to 20 ns are presented. These results suggest that the laser intensity scaling law of ablation pressure differs for different pulse durations. And the theoretical analysis shows that the effects of laser pulse duration on ablation pressure are mainly caused by two regimes: the unsteady-state flow and the radiative energy loss to vacuum.

  7. Progress on developing a PW ultrashort laser facility with ns, ps, and fs outputting pulses

    NASA Astrophysics Data System (ADS)

    Zhu, Qihua; Huang, Xiaojun; Wang, Xiao; Zeng, Xiaoming; Xie, Xudong; Wang, Fang; Wang, Fengrui; Lin, Donghui; Wang, Xiaodong; Zhou, Kainan; Jiang, Dongbin; Deng, Wu; Zuo, Yanlei; Zhang, Ying; Deng, Ying; Wei, Xiaofeng; Zhang, Xiaomin; Fan, Dianyuan

    2008-03-01

    A petawatt laser facility with three beams for fast ignition research and strong-field physics applications has been designed and is being constructed. The first beam (referred as SILEX-I) is a Ti:sapphire femto-second laser which pulse width is 30 fs, and till now, output power has reached to 330 TW. The other two beams are Nd 3+:glass lasers which output energy are larger than 1kJ and pulse width are about 1ps and 1ns respectively. By using the technology of OPA pumped by 800nm femtosecond laser and seeded by super-continuum spectrum white light, the three beams are synchronized with each other without jitter time. By using the seeds from OPA pumped by femtosecond laser, and by using the pre-amplification stage of OPCPA, the signal to noise ratio of the Nd 3+:glass petawatt laser will reach to 10 8. Active methods are taken to control the gain narrowing effect of the Nd 3+:glass amplifiers, giving the option to compress the chirped pulse to ultrashort pulse with width less than 400fs. Tiled multilayer dielectric coating gratings are used for the compressor of the PW beam, which has been successfully demonstrated on a 100J picosecond Nd 3+:glass laser system.

  8. Terahertz radiation from a wire target irradiated by an ultra-intense laser pulse

    SciTech Connect

    Li Zhichao; Zheng Jian

    2007-05-15

    When an ultra-intense laser pulse impacts the tip of a wire whose other end is grounded, a strong return current can be driven along the wire because some energetic electrons generated in ultra-intense laser matter interaction can escape from the target and an electric field builds up. The wire then behaves like a current-carrying antenna that can emit electromagnetic radiations. If the duration of the driving pulse is several tens of femtoseconds, the radiation spectrum reaches a maximum at terahertz region, and the radiation power per solid angle could be as high as 10{sup 9} W/rad.

  9. Design and construction of a PW ultrashort laser facility with ns, ps, and fs outputting pulses

    NASA Astrophysics Data System (ADS)

    Zhu, Qihua; Huang, Xiaojun; Wang, Xiao; Zeng, Xiaoming; Xie, Xudong; Wang, Fang; Wang, Fengrui; Lin, Donghui; Jiang, Dongbin; Wang, Xiaodong; Zhou, Kainan; Zuo, Yanlei; Zhang, Ying; Deng, Ying; Wei, Xiaofeng; Fan, Dianyuan

    2007-06-01

    A petawatt laser facility with three beams for fast ignition research and strong-field physics applications has been designed and is being constructed. The first beam (referred as SILEX-I) is a Ti:sapphire femto-second laser which pulse width is 30 fs, and till now, output power has reached to 330 TW. The other two beams are Nd 3+:glass lasers which output energy are larger than 1kJ and pulse width are about 1ps and 1ns respectively. By using the technology of OPA pumped by 800nm femtosecond laser and seeded by super-continuum white light (SWL), the three beams are synchronized with each other without jitter time. Tiled multilayer dielectric coating gratings are used for the compressor of the PW beam.

  10. Intense Nanosecond-Pulsed Cavity-Dumped Laser Radiation at 1.04 THz

    NASA Astrophysics Data System (ADS)

    Wilson, Thomas

    2013-03-01

    We report first results of intense far-infrared (FIR) nanosecond-pulsed laser radiation at 1.04 THz from a previously described[2] cavity-dumped, optically-pumped molecular gas laser. The gain medium, methyl fluoride, is pumped by the 9R20 line of a TEA CO2 laser[3] with a pulse energy of 200 mJ. The THz laser pulses contain of 30 kW peak power in 5 nanosecond pulse widths at a pulse repetition rate of 10 Hz. The line width, measured by a scanning metal-mesh FIR Fabry-Perot interferometer, is 100 MHz. The novel THz laser is being used in experiments to resonantly excite coherent ns-pulsed 1.04 THz longitudinal acoustic phonons in silicon doping-superlattices. The research is supported by NASA EPSCoR NNX11AM04A and AFOSR FA9550-12-1-0100 awards.

  11. Observation of coherent undulator radiation from sub-picosecond electron pulses

    SciTech Connect

    Bocek, D.; Hernandez, M.; Kung, P.; Lihn, Hung-chi; Settakorn, C.; Wiedemann, H.

    1995-09-01

    The generation and observation of high power, coherent, far-infrared undulator radiation from sub-picosecond electron bunches at the SUNSHINE facility is reported. Coherent undulator radiation tunable from 50 to 200 microns wavelength is demonstrated. Measurements of the energy (up to 1.7 mJ per 1 microsecs macropulse), frequency spectrum, and spatial distribution of the radiation are reported. Apparent exponential growth of the radiated energy as a function of undulator length is observed.

  12. Dynamics of ultrashort pulsed laser radiation induced non-thermal ablation of graphite

    NASA Astrophysics Data System (ADS)

    Reininghaus, M.; Kalupka, C.; Faley, O.; Holtum, T.; Finger, J.; Stampfer, C.

    2014-12-01

    We report on the dependence of a laser radiation induced ablation process of graphite on the applied pulse duration of ultrashort pulsed laser radiation smaller than 4 ps. The emerging so-called non-thermal ablation process of graphite has been confirmed to be capable to physically separate ultrathin graphitic layers from the surface of pristine graphite bulk crystal. This allows the deposition of ablated graphitic flakes on a substrate in the vicinity of the target. The observed ablation threshold determined at different pulse durations shows a modulation, which we ascribe to lattice motions along the c axis that are theoretically predicted to induce the non-thermal ablation process. In a simple approach, the ablation threshold can be described as a function of the energy penetration depth and the absorption of the applied ultrashort pulsed laser radiation. Based on the analysis of the pulse duration dependence of those two determining factors and the assumption of an invariant ablation process, we are able to reproduce the pulse duration dependence of the ablation threshold. Furthermore, the observed pulse duration dependences confirm the assumption of a fast material specific response of graphite target subsequent to optical excitation within the first 2 ps.

  13. Central Japan Synchrotron Radiation Research Facility Project-(II)

    SciTech Connect

    Yamamoto, N.; Takashima, Y.; Hosaka, M.; Takami, K.; Morimoto, H.; Ito, T.; Sakurai, I.; Hara, H.; Okamoto, W.; Watanabe, N.; Takeda, Y.; Katoh, M.; Hori, Y.; Sasaki, S.

    2010-06-23

    A synchrotron radiation facility that is used not only for basic research, but also for engineering and industrial research and development has been proposed to be constructed in the Central area of Japan. The key equipment of this facility is a compact electron storage ring that is able to supply hard X-rays. The circumference of the storage ring is 72 m with the energy of 1.2 GeV, the beam current of 300 mA, and the natural emittance of about 53 nm-rad. The configuration of the storage ring is based on four triple bend cells, and four of the twelve bending magnets are 5 T superconducting ones. The bending angle and critical energy are 12 degree and 4.8 keV, respectively. For the top-up operation, the electron beam will be injected from a booster synchrotron with the full energy. Currently, six beamlines are planned for the first phase starting from 2012.

  14. The origin of changes in the electronic structure of oriented multi-walled carbon nanotubes under the influence of pulsed ion radiation

    NASA Astrophysics Data System (ADS)

    Bolotov, V. V.; Korusenko, P. M.; Nesov, S. N.; Povoroznyuk, S. N.; Knyazev, E. V.

    2014-10-01

    On the basis of spectra obtained through the X-ray Auger-electron spectroscopy (XAES) of carbon (C KVV) and X-ray photoelectron spectroscopy (XPS) of the carbon valence band using the equipment of the Russian-German beam line of the synchrotron radiation facility BESSY II and a Kratos Axis Ultra DLD analytical system, the influence of pulsed ion radiation on the ratio of sp2/sp3-hybridized orbitals of carbon atoms in layers of oriented multi-walled carbon nanotubes (MWCNTs) is investigated. It is shown that when the MWCNTs are subjected to ten pulses, a substantial increase in the proportion of carbon atoms in the sp3 hybridization state occurs compared with MWCNTs subjected to a single pulse. This increase is associated with the formation of thin (<10 nm) nanotubes and onion-like carbon, inside which masses of nanodiamond structures are observed in some cases.

  15. Testing and Research Capabilities at the Sandia Fast Pulsed Reactor Facility

    NASA Astrophysics Data System (ADS)

    Berry, Donald T.

    1994-07-01

    A wide variety of space-based system components have been qualified for use through neutron irradiation testing performed at the Sandia Pulsed Reactor (SPR) Facility. The SPR Facility is the operating location for two fast burst reactors, SPR II and SPR III, which have been used to induce neutron and gamma damage in electronic components and other materials for customers in the Department of Energy, Department of Defense, NASA, and the private sector. In addition to the pulse mode of operation, during which peak fluxes of up to 1023 n/m2-s are achieved, the steady state mode allows for the long term irradiation of components and systems in a fast neutron environment at a flux of up to 5×1015 n/m2-s. The SPR reactors are operated in a 9.2 meter diameter exposure cell, or Kiva, suitable for the irradiation of large test articles external to the reactors. Currently, a new upgraded version of SPR III (SPR HIM) is in fabrication; a unique feature of SPR HIM is its 190 mm (usable diameter) central irradiation cavity, the largest of any U.S. fast burst reactor. An improved cooling system permits continuous operation at power levels in excess of 20 kWt. The SPR Facility is also the operating site for a critical assembly which was used to characterize prototypic fuels in arrays appropriate for the Space Nuclear Thermal Propulsion Program. Work continues on use of the facility to design, build, and operate critical assemblies for a diverse customer base.

  16. Methods and devices for generation of broadband pulsed radiation

    DOEpatents

    Borguet, Eric; Isaienko, Oleksandr

    2013-05-14

    Methods and apparatus for non-collinear optical parametric ampliffication (NOPA) are provided. Broadband phase matching is achieved with a non-collinear geometry and a divergent signal seed to provide bandwidth gain. A chirp may be introduced into the pump pulse such that the white light seed is amplified in a broad spectral region.

  17. Atmospheric Radiation Measurement Program facilities newsletter, July 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-07-23

    Global Warming and Methane--Global warming, an increase in Earth's near-surface temperature, is believed to result from the buildup of what scientists refer to as ''greenhouse gases.'' These gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone, perfluorocarbons, hydrofluoro-carbons, and sulfur hexafluoride. Greenhouse gases can absorb outgoing infrared (heat) radiation and re-emit it back to Earth, warming the surface. Thus, these gases act like the glass of a greenhouse enclosure, trapping infrared radiation inside and warming the space. One of the more important greenhouse gases is the naturally occurring hydrocarbon methane. Methane, a primary component of natural gas, is the second most important contributor to the greenhouse effect (after carbon dioxide). Natural sources of methane include wetlands, fossil sources, termites, oceans, fresh-waters, and non-wetland soils. Methane is also produced by human-related (or anthropogenic) activities such as fossil fuel production, coal mining, rice cultivation, biomass burning, water treatment facilities, waste management operations and landfills, and domesticated livestock operations (Figure 1). These anthropogenic activities account for approximately 70% of the methane emissions to the atmosphere. Methane is removed naturally from the atmosphere in three ways. These methods, commonly referred to as sinks, are oxidation by chemical reaction with tropospheric hydroxyl ion, oxidation within the stratosphere, and microbial uptake by soils. In spite of their important role in removing excess methane from the atmosphere, the sinks cannot keep up with global methane production. Methane concentrations in the atmosphere have increased by 145% since 1800. Increases in atmospheric methane roughly parallel world population growth, pointing to anthropogenic sources as the cause (Figure 2). Increases in the methane concentration reduce Earth's natural cooling efficiency by trapping more of the outgoing

  18. Atmospheric radiation measurement program facilities newsletter, July 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-08-12

    ARM Participating in Off-site Intensive Operational Period--The ARM Program is playing a role in the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) intensive operational period (IOP), under way through July in South Florida. The objective of CRYSTAL-FACE is to investigate the physical properties and formation processes of tropical cirrus clouds. The ARM Program has deployed a suite of ground-based instruments in Florida for CRYSTAL-FACE. In addition, the National Aeronautics and Space Administration provides six research aircraft equipped with state-of-the-art instruments to measure characteristics of cirrus clouds and their ability to alter the temperature of the atmosphere. The reliability of climate predictions depends on the accuracy of computer models of climate. Interactions between clouds and solar radiation are a major source of current uncertainty in the models, hindering accurate climate prediction. A goal of CRYSTAL-FACE is to improve on the way clouds are represented in and integrated into the models and thus achieve more reliable climate predictions. CRYSTAL-FACE will be followed in 2004 by CRYSTAL-TWP, to be held at ARM's Tropical Western Pacific (TWP) location on Manus and Nauru Islands. New Storage Building Proposed for Central Facility--Now in the design phase is a new storage building to be erected at the central facility, west of the shipping and receiving trailer. The added storage is needed because shipping needs for the TWP are now being handled by the SGP site. New Seminole Extended Facility Location Approved--The extended facility formerly on the property of the Seminole Industrial Foundation had to be removed from service in April, after the land was sold to a new owner. Both the foundation and the new land owner offered options for new extended facility locations in the area. An Environmental Evaluation Notification Form has now been approved by the USDOE (ARM Program sponsor), as

  19. Thermomechanical effect of pulse-periodic laser radiation on cartilaginous and eye tissues

    NASA Astrophysics Data System (ADS)

    Baum, O. I.; Zheltov, G. I.; Omelchenko, A. I.; Romanov, G. S.; Romanov, O. G.; Sobol, E. N.

    2013-08-01

    This paper is devoted to theoretical and experimental studies into the thermomechanical action of laser radiation on biological tissues. The thermal stresses and strains developing in biological tissues under the effect of pulse-periodic laser radiation are theoretically modeled for a wide range of laser pulse durations. The models constructed allow one to calculate the magnitude of pressures developing in cartilaginous and eye tissues exposed to laser radiation and predict the evolution of cavitation phenomena occurring therein. The calculation results agree well with experimental data on the growth of pressure and deformations, as well as the dynamics of formation of gas bubbles, in the laser-affected tissues. Experiments on the effect of laser radiation on the trabecular region of the eye in minipigs demonstrated that there existed optimal laser irradiation regimens causing a substantial increase in the hydraulic permeability of the radiation-exposed tissue, which can be used to develop a novel glaucoma treatment method.

  20. Bursts of Terahertz Radiation from Large-Scale Plasmas Irradiated by Relativistic Picosecond Laser Pulses.

    PubMed

    Liao, G Q; Li, Y T; Li, C; Su, L N; Zheng, Y; Liu, M; Wang, W M; Hu, Z D; Yan, W C; Dunn, J; Nilsen, J; Hunter, J; Liu, Y; Wang, X; Chen, L M; Ma, J L; Lu, X; Jin, Z; Kodama, R; Sheng, Z M; Zhang, J

    2015-06-26

    Powerful terahertz (THz) radiation is observed from large-scale underdense preplasmas in front of a solid target irradiated obliquely with picosecond relativistic intense laser pulses. The radiation covers an extremely broad spectrum with about 70% of its energy located in the high frequency regime over 10 THz. The pulse energy of the radiation is found to be above 100  μJ per steradian in the laser specular direction at an optimal preplasma scale length around 40-50  μm. Particle-in-cell simulations indicate that the radiation is mainly produced by linear mode conversion from electron plasma waves, which are excited successively via stimulated Raman scattering instability and self-modulated laser wakefields during the laser propagation in the preplasma. This radiation can be used not only as a powerful source for applications, but also as a unique diagnostic of parametric instabilities of laser propagation in plasmas. PMID:26197129

  1. Formation of ultrashort pulses from quasimonochromatic XUV radiation via infrared-field-controlled forward scattering

    NASA Astrophysics Data System (ADS)

    Akhmedzhanov, T. R.; Antonov, V. A.; Kocharovskaya, Olga

    2016-08-01

    We suggest a highly efficient method of ultrashort pulse formation from resonant XUV radiation due to sub-laser-cycle modulation of the excited state of non-hydrogen-like atoms by a nonionizing IR laser field. This modulation results in formation of the Raman-Stokes and anti-Stokes sidebands in coherently forward-scattered radiation, which, in turn, leads to formation of short pulses, when the phases of the sidebands are matched. This method is a generalization of a recently suggested technique [V. A. Antonov et al., Phys. Rev. A 88, 053849 (2013), 10.1103/PhysRevA.88.053849] for a non-hydrogen-like medium. The possibility to form 2-fs XUV pulses in the gas of helium atoms and 990-as XUV pulses in the plasma of Li+ ions with efficiencies over 80% is shown.

  2. Techniques for synchronization of X-Ray pulses to the pump laser in an ultrafast X-Ray facility

    SciTech Connect

    Corlett, J.N.; Doolittle, L.; Schoenlein, R.; Staples, J.; Wilcox, R.; Zholents, A.

    2003-05-06

    Accurate timing of ultrafast x-ray probe pulses emitted from a synchrotron radiation source with respect to the signal initiating a process in the sample under study is critical for the investigation of structural dynamics in the femtosecond regime. We describe schemes for achieving accurate timing of femtosecond x-ray synchrotron radiation pulses relative to a pump laser, where x-rays pulses of <100 fs duration are generated from the proposed LUX source based on a recirculating superconducting linac. We present a description of the timing signal generation and distribution systems to minimize timing jitter of the x-rays relative to the experimental lasers.

  3. Generation of Widely Tunable Fourier-Transform Pulsed Terahertz Radiation Using Narrowband Near-Infrared Laser Radiation

    NASA Astrophysics Data System (ADS)

    Liu, Jinjun; Haase, Christa; Merkt, Frédéric

    2009-06-01

    Widely tunable, Fourier-transform-limited pulses of terahertz (THz) radiation have been generated by optical frequency deference using (i) crystals of the highly nonlinear organic salt 4-N,N-dimethylamino-4^'-N^'-methyl stilbazolium tosylate (DAST), (ii) zinc telluride (ZnTe) crystals, and (iii) gallium phosphide (GaP) crystals. Outputs from two narrowband (Δν<1 MHz, λ˜800 nm) cw titanium-doped sapphire (Ti:Sa) ring lasers with a well-controlled frequency difference were shaped into pulses using acousto-optic modulators, coupled into an optical fiber, pulse amplified in Nd:YAG-pumped Ti:Sa crystals and used as optical sources to pump the THz nonlinear crystals. The THz radiation was detected over a broad frequency range and its bandwidth was determined to be ˜10 MHz. Absorption spectra of gas phase molecules including HF and OCS using the THz source will be presented.

  4. Radiated Emission of Breath Monitoring System Based on UWB Pulses in Spacecraft Modules

    NASA Astrophysics Data System (ADS)

    Russo, P.; Mariani Primiani, V.; De Leo, A.; Cerri, G.

    2012-05-01

    The paper describes some EMC aspects related to a UWB radar for monitoring astronauts breathing activity. Compliance to EMC space standards forces some design aspects, in particular the peak voltage and the pulse waveform. Moreover some simulations were carried out to consider realistic operating condition. In the first case the interference towards a victim wifi circuit was analyzed, in the second case the effect of the environment on the radiated pulse was studied.

  5. Thermal nuclear pulse simulation at the National Solar Thermal Test Facility

    SciTech Connect

    Cameron, C.P.; Ralph, M.E. ); Ghanbari, C.M. ); Oeding, R.; Shaw, K. )

    1991-01-01

    The National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories in Albuquerque, New Mexico is being used to simulate the thermal pulse from a nuclear weapon on relatively large surfaces. Pulses varying in length from 2 seconds to 7 seconds have been produced. The desired pulse length varies as a function of the yield of the weapon being simulated. The present experiment capability can accommodate samples as large as 1.2 {times} 1.5 meters. Samples can be flat or three-dimensional. Samples exposed have ranged from fabrics (protective clothing) to an aircraft canopy and cockpit system, complete with a mannequin in a flight suit and helmet. In addition, a windowed wind tunnel has been constructed which permits exposure of flight surface materials to thermal transients with air speed of Mach 0.8. The wind tunnel can accommodate samples up to .48 {times} .76 meters or an array of smaller samples. The maximum flux capability of the NSTTF is about 70 calories/cm{sup 2}-sec. A black-body temperature of about 6000 K is produced by the solar beam and is therefore ideal for simulating the nuclear source. 3 refs., 7 figs.

  6. Controlling the Radiation Parameters of a Resonant Medium Excited by a Sequence of Ultrashort Superluminal Pulses

    NASA Astrophysics Data System (ADS)

    Arkhipov, R. M.; Arkhipov, M. V.; Belov, P. A.; Babushkin, I.; Tolmachev, Yu. A.

    2016-03-01

    We investigate the possibility of controlling the radiation parameters of a spatially periodic one-dimensional medium consisting of classical harmonic oscillators by means of a sequence of ultrashort pulses that propagate through the medium with a superluminal velocity. We show that, in the spectrum of the transient process, in addition to the radiation at a resonant frequency of oscillators, new frequencies arise that depend on the period of the spatial distribution of the oscillator density, the excitation velocity, and the angle of observation. We have examined in detail the case of excitation of the medium by a periodic sequence of ultrashort pulses that travel with a superluminal velocity. We show that it is possible to excite oscillations of complex shapes and to control the radiation parameters of the resonant medium by changing the relationship between the pulse repetition rate, the medium resonant frequency, and the new frequency.

  7. Application of DNA comet assay for detection of radiation treatment of grams and pulses.

    PubMed

    Khan, Hasan M; Khan, Ashfaq A; Khan, Sanaullah

    2011-12-01

    Several types of whole pulses (green lentils, red lentils, yellow lentils, chickpeas, green peas, cowpeas and yellow peas) and grams (black grams, red grams and white grams) have been investigated for the identification of radiation treatment using microgel electrophoresis of single cells (DNA comet assay). Pulses and grams were exposed to the radiation doses of 0.5, 1.0 and 5 kGy covering the legalized commercial dose range for protection from insect/pest infestations. All irradiated samples showed comet like stretching of fragmented DNA toward anode, which is expected for irradiated samples. Unirradiated samples showed many intact cells/nuclei in form of round stains or with short faint tails, which is typical for unirradiated food samples. The study shows that DNA comet assay can be used as a rapid, inexpensive and highly effective screening test for the detection of radiation treatment of foods, like pulses and grams. PMID:23572810

  8. Radiation pressure acceleration of protons to 93 MeV with circularly polarized petawatt laser pulses

    NASA Astrophysics Data System (ADS)

    Kim, I. Jong; Pae, Ki Hong; Choi, Il Woo; Lee, Chang-Lyoul; Kim, Hyung Taek; Singhal, Himanshu; Sung, Jae Hee; Lee, Seong Ku; Lee, Hwang Woon; Nickles, Peter V.; Jeong, Tae Moon; Kim, Chul Min; Nam, Chang Hee

    2016-07-01

    The radiation pressure acceleration (RPA) of charged particles has been a challenging task in laser-driven proton/ion acceleration due to its stringent requirements in laser and target conditions. The realization of radiation-pressure-driven proton acceleration requires irradiating ultrathin targets with an ultrahigh contrast and ultraintense laser pulses. We report the generation of 93-MeV proton beams achieved by applying 800-nm 30-fs circularly polarized laser pulses with an intensity of 6.1 × 10 20 W / cm 2 to 15-nm-thick polymer targets. The radiation pressure acceleration was confirmed from the obtained optimal target thickness, quadratic energy scaling, polarization dependence, and three-dimensional particle-in-cell simulations. We expect this clear demonstration of RPA to facilitate the realization of laser-driven proton/ion sources delivering energetic and short-pulse particle beams for novel applications.

  9. Development of a 50-T pulsed magnetic field facility by using an 1.5-MJ capacitor bank

    NASA Astrophysics Data System (ADS)

    Shin, Y. H.; Kim, Yongmin

    2015-09-01

    Because DC magnets consume a huge amount of electricity (resistive DC magnet) or liquid helium (superconducting magnet), a capacitor-bank-driven pulsed magnet is known to be a cost-effective way of generating high magnetic fields. This type of pulsed magnet is normally operated at liquid nitrogen temperature and consumes little electric power to generate over 50 tesla (T) during a short transient time of less than 50 millisecond (ms). With modern fast data acquisition systems, almost all kinds of physical quantities, such as photoluminescence, magnetization or resistance can be measured during a short magnetic field pulse. We report a recently home-built capacitor-bankdriven pulsed magnetic field facility, in which a capacitor bank of 1.5-MJ maximum stored energy is utilized to generate pulsed magnetic fields up to 50 T with transient pulse time of 22 ms.

  10. Energy gain of an electron by a laser pulse in the presence of radiation reaction

    SciTech Connect

    Lehmann, G.; Spatschek, K. H.

    2011-10-15

    A well-known no-energy-gain theorem states that an electron cannot gain energy when being overrun by a plane (transverse) laser pulse of finite length. The theorem is based on symmetries which are broken when radiation reaction (RR) is included. It is shown here that an electron, e.g., being initially at rest, will gain a positive velocity component in the laser propagation direction after being overrun by an intense laser pulse (of finite duration and with intensity of order 5x10{sup 22} W/cm{sup 2} or larger). The velocity increment is due to RR effects. The latter are incorporated in the Landau-Lifshitz form. Both linear as well as circular polarization of the laser pulse are considered. It is demonstrated that the velocity gain is proportional to the pulse length and the square of the peak amplitude of the laser pulse. The results of numerical simulations are supported by analytical estimates.

  11. Radiation field characterization and shielding studies for the ELI Beamlines facility

    NASA Astrophysics Data System (ADS)

    Ferrari, A.; Amato, E.; Margarone, D.; Cowan, T.; Korn, G.

    2013-05-01

    The ELI (Extreme Light Infrastructure) Beamlines facility in the Czech Republic, which is planned to complete the installation in 2015, is one of the four pillars of the ELI European project. Several laser beamlines with ultrahigh intensities and ultrashort pulses are foreseen, offering versatile radiation sources in an unprecedented energy range: laser-driven particle beams are expected to range between 1 and 50 GeV for electrons and from 100 MeV up to 3 GeV for protons. The number of particles delivered per laser shot is estimated to be 109-1010 for the electron beams and 1010-1012 for the proton beams. The high energy and current values of the produced particles, together with the potentiality to operate at 10 Hz laser repetition rate, require an accurate study of the primary and secondary radiation fields to optimize appropriate shielding solutions: this is a key issue to minimize prompt and residual doses in order to protect the personnel, reduce the radiation damage of electronic devices and avoid strong limitations in the operational time. A general shielding study for the 10 PW (0.016 Hz) and 2 PW (10 Hz) laser beamlines is presented here. Starting from analytical calculations, as well as from dedicated simulations, the main electron and proton fields produced in the laser-matter interaction have been described and used to characterize the "source terms" in full simulations with the Monte Carlo code FLUKA. The secondary radiation fields have been then analyzed to assess a proper shielding. The results of this study and the proposed solutions for the beam dumps of the high energy beamlines, together with a cross-check analysis performed with the Monte Carlo code GEANT4, are presented.

  12. Generating high-power short terahertz electromagnetic pulses with a multifoil radiator.

    PubMed

    Vinokurov, Nikolay A; Jeong, Young Uk

    2013-02-01

    We describe a multifoil cone radiator capable of generating high-field short terahertz pulses using short electron bunches. Round flat conducting foil plates with successively decreasing radii are stacked, forming a truncated cone with the z axis. The gaps between the foil plates are equal and filled with some dielectric (or vacuum). A short relativistic electron bunch propagates along the z axis. At sufficiently high particle energy, the energy losses and multiple scattering do not change the bunch shape significantly. When passing by each gap between the foil plates, the electron bunch emits some energy into the gap. Then, the radiation pulses propagate radially outward. For transverse electromagnetic waves with a longitudinal (along the z axis) electric field and an azimuthal magnetic field, there is no dispersion in these radial lines; therefore, the radiation pulses conserve their shapes (time dependence). At the outer surface of the cone, we have synchronous circular radiators. Their radiation field forms a conical wave. Ultrashort terahertz pulses with gigawatt-level peak power can be generated with this device. PMID:23432259

  13. Pulse

    MedlinePlus

    Heart rate; Heart beat ... The pulse can be measured at areas where an artery passes close to the skin. These areas include the: ... side of the foot Wrist To measure the pulse at the wrist, place the index and middle ...

  14. Innovative uses for conventional radiation detectors via pulse shape analysis

    SciTech Connect

    Beckedahl, D; Blair, J; Friensehner, A; Kammeraad, J E; Schmid, G

    1999-03-03

    In this report we have discussed two applications for digital pulse shape analysis in Ge detectors: Compton suppression and {gamma}-ray imaging. The Compton suppression aspect has been thoroughly studied during the past few years, and a real-time, laboratory-prototype system has been fielded. A summary of results from that set up have been discussed here. The {gamma}-ray imaging aspect, while not yet developed experimentally, looks very promising theoretically as the simulations presented here have shown. Experimental work currently underway at Berkeley (as discussed in section 4.3) should help further guide us towards the proper developmental path.

  15. Surface shortwave aerosol radiative forcing during the Atmospheric Radiation Measurement Mobile Facility deployment in Niamey, Niger

    SciTech Connect

    McFarlane, Sally A.; Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Ackerman, Thomas P.

    2009-03-18

    This study presents ground-based remote sensing measurements of aerosol optical properties and corresponding shortwave surface radiative effect calculations for the deployment of the Atmospheric Radiation Measurement (ARM) Program’s Mobile Facility (AMF) to Niamey, Niger during 2006. Aerosol optical properties including aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (AP) were derived from multi-filter rotating shadowband radiometer (MFRSR) measurements during the two dry seasons (Jan-Apr and Oct-Dec) at Niamey. The vertical distribution of aerosol extinction was derived from the collocated micropulse lidar (MPL). The aerosol optical properties and vertical distribution of extinction varied significantly throughout the year, with higher AOD, lower SSA, and deeper aerosol layers during the Jan-Apr time period, when biomass burning aerosol layers were more frequent. Using the retrieved aerosol properties and vertical extinction profiles, broadband shortwave surface fluxes and atmospheric heating rate profiles were calculated. Corresponding calculations with no aerosol were used to estimate the aerosol direct radiative effect at the surface. Comparison of the calculated surface fluxes to observed fluxes for non-cloudy periods indicated that the remote sensing retrievals provided a reasonable estimation of the optical properties, with mean differences between calculated and observed fluxes of less than 5 W/m2 and RMS differences less than 25 W/m2. Sensitivity tests for a particular case study showed that the observed fluxes could be matched with variations of < 10% in the inputs to the radiative transfer model. We estimated the daily-averaged aerosol radiative effect at the surface by subtracting the clear calculations from the aerosol calculations. The average daily SW aerosol radiative effect over the study period was -27 W/m2, which is comparable to values estimated from satellite data and from climate models with sophisticated

  16. Inactivation of E. Coli cell viability and DNA Photo-breakage by Pulsed Nitrogen Laser Radiation

    SciTech Connect

    Cheba, Ben Amar; Alzaag, Ali; Tilfah, Nafie A.

    2005-03-17

    The mutagenic and lethal effect of nitrogen laser radiation: 337.1 nm wave length, 1.5 millijoul pulse energy, 10 nanosecond pulse with and pulse repetition rate range from 1 to 50 Pulse/ second was evaluated on E. Coli cells. Results indicated that irradiation of E. coli JMP39 with pulse repetition of 8 , 16 , 32 pulse/sec, for 1, 5 , 10, 25 min respectively led to a significant decrease in cell count proportional to irradiation dose with significant increase in lacmutation frequency accompanied with some mutations in pattern of antibiotic resistance. The effect of nitrogen laser on the genomic content of the strain JMP39 was also studied by irradiating the total DNA with 30 pulse/second for 1 ,5, 15 , 30 min then subjected to both agarose gel electrophoresis and scanning spectrophotometry. The first technique revealed to DNA photo breakage and significant decrease in DNA absorbency was noticed by scanning spectrophotometry. This could be attributed to photo-decomposition resulted from multi-photo-excitation of UV-Laser pulses.

  17. Transient Self-Amplified Cerenkov Radiation with a Short Pulse Electron Beam

    SciTech Connect

    Poole, B R; Blackfield, D T; Camacho, J F

    2009-01-22

    An analytic and numerical examination of the slow wave Cerenkov free electron maser is presented. We consider the steady state amplifier configuration as well as operation in the selfamplified spontaneous emission (SASE) regime. The linear theory is extended to include electron beams that have a parabolic radial density inhomogeneity. Closed form solutions for the dispersion relation and modal structure of the electromagnetic field are determined in this inhomogeneous case. To determine the steady state response, a macro-particle approach is used to develop a set of coupled nonlinear ordinary differential equations for the amplitude and phase of the electromagnetic wave, which are solved in conjunction with the particle dynamical equations to determine the response when the system is driven as an amplifier with a time harmonic source. We then consider the case in which a fast rise time electron beam is injected into a dielectric loaded waveguide. In this case, radiation is generated by SASE, with the instability seeded by the leading edge of the electron beam. A pulse of radiation is produced, slipping behind the leading edge of the beam due to the disparity between the group velocity of the radiation and the beam velocity. Short pulses of microwave radiation are generated in the SASE regime and are investigated using particle-in-cell (PIC) simulations. The nonlinear dynamics are significantly more complicated in the transient SASE regime when compared with the steady state amplifier model due to the slippage of the radiation with respect to the beam. As strong self-bunching of the electron beam develops due to SASE, short pulses of superradiant emission develop with peak powers significantly larger than the predicted saturated power based on the steady state amplifier model. As these superradiant pulses grow, their pulse length decreases and forms a series of soliton-like pulses. Comparisons between the linear theory, macro-particle model, and PIC simulations are

  18. Fast E-field switching of a pulsed surface muon beam: The commissioning of the European muon facility at ISIS

    NASA Astrophysics Data System (ADS)

    Eaton, G. H.; Clarke-Gayther, M. A.; Scott, C. A.; Uden, C. N.; Williams, W. G.

    1994-03-01

    The ISIS pulsed muon facility at RAL has been upgraded by the inclusion of a fast E-field kicker which simultaneously divides and distributes the muon pulses at surface momentum to the three experimental areas at a repetition rate of 50 Hz. This upgraded facility has been successfully commissioned in conjunction with a new μSR spectrometer. It has been shown that this new spectrometer can operate as expected with a figure of merit for μSR experiments similar to that of the original spectrometer, in spite of receiving only half of the relative muon intensity. This twofold increase in experimental capability will be further increased in the near future by the incorporation of experimental equipment in the third beamline. Such a facility will be capable of satisfying a European wide demand for μSR research with pulsed surface muons.

  19. Radiation Safety Aspects for Pulsed Photonuclear Assessment Techniques in Outdoor Operations

    SciTech Connect

    Daren R. Norman; James L. Jones; Brandon W. Blackburn; Allen Fisher; Scott M. Watson; Kevin J. Haskell; Alan W. Hunt; Mark Balzer

    2007-08-01

    As many pulsed photonuclear assessment (PPA) technologies are being developed for contraband detection within cargo container configurations, the radiation safe operation of source linacs for outdoor operations needs to be addressed. Idaho National Laboratory along with Idaho Accelerator Center are conducting field operations with high energy linacs in open outdoor configurations. The relevant information pertaining to the radiation regulations and dosimetry studies for these configurations will be presented for a prototypical 10 MeV PPA nuclear material detection system.

  20. ASSESSMENT OF THE IMMUNE RESPONSIVENESS OF MICE IRRADIATED WITH CONTINUOUS WAVE OR PULSE-MODULATED 425-MHZ RADIO FREQUENCY RADIATION

    EPA Science Inventory

    Groups of female BALB/C mice were irradiated with 425-MHz radio frequency (RF) radiation either continuous wave (CW) or pulse modulated (PM, 1-ms pulse width, 250 pulses/s). Mice were irradiated in a rectangular strip-transmission line at average forward powers of 78, 17.7, or 5 ...

  1. Generation of scalable terahertz radiation from cylindrically focused laser pulses in air

    NASA Astrophysics Data System (ADS)

    Kuk, Donghoon; Yoo, Yungjun; Rosenthal, Eric; Jhajj, Nihal; Milchberg, Howard; Kim, Ki-Yong

    We have demonstrated scalable terahertz (THz) generation via cylindrical focusing of two-color laser pulses in air. In this experiment, we have used a terawatt (TW) laser system which can deliver >50 mJ, 800 nm, 50 fs pulses at a 10 Hz repetition rate. A 800 nm pulse passing through a nonlinear crystal (BBO) generates its second harmonic pulse (400 nm). Both pulses pass through a cylindrical lens and are focused together to generate a 2-dimensional plasma sheet in air. This yields two diverging THz lobes, characterized by an uncooled microbolometer. This observed radiation angle and pattern is explained by the optical-Cherenkov radiation theory. The diverging THz radiation is re-focused to yield strong THz field strengths (>20 MV/cm) at the focus. At laser energy of 40 mJ, cylindrical focusing provides THz energy of >30 microjoules, far exceeding the output produced by spherical focusing. This shows that cylindrical focusing can effectively minimize ionization-induced defocusing, previously observed in spherical focusing, and can allow scalable THz generation with relatively high laser energies (>20 mJ). Work supported by DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. 014216-001.

  2. A source of high-power pulses of elliptically polarized ultrawideband radiation.

    PubMed

    Andreev, Yu A; Efremov, A M; Koshelev, V I; Kovalchuk, B M; Petkun, A A; Sukhushin, K N; Zorkaltseva, M Yu

    2014-10-01

    Here, we describe a source of high-power ultrawideband radiation with elliptical polarization. The source consisting of a monopolar pulse generator, a bipolar pulse former, and a helical antenna placed into a radioparent container may be used in tests for electromagnetic compatibility. In the source, the helical antenna with the number of turns N = 4 is excited with a high-voltage bipolar pulse. Preliminary, we examined helical antennas at a low-voltage source aiming to select an optimal N and to estimate a radiation center position and boundary of a far-field zone. Finally, characteristics of the source in the operating mode at a pulse repetition rate of 100 Hz are presented in the paper as well. Energy efficiency of the antenna is 0.75 at the axial ratio equal to 1.3. The effective potential of radiation of the source at the voltage amplitudes of the bipolar pulse generator equal to -175/+200 kV reaches 280 kV. PMID:25362430

  3. A source of high-power pulses of elliptically polarized ultrawideband radiation

    SciTech Connect

    Andreev, Yu. A. Efremov, A. M.; Koshelev, V. I.; Kovalchuk, B. M.; Petkun, A. A.; Sukhushin, K. N.; Zorkaltseva, M. Yu.

    2014-10-01

    Here, we describe a source of high-power ultrawideband radiation with elliptical polarization. The source consisting of a monopolar pulse generator, a bipolar pulse former, and a helical antenna placed into a radioparent container may be used in tests for electromagnetic compatibility. In the source, the helical antenna with the number of turns N = 4 is excited with a high-voltage bipolar pulse. Preliminary, we examined helical antennas at a low-voltage source aiming to select an optimal N and to estimate a radiation center position and boundary of a far-field zone. Finally, characteristics of the source in the operating mode at a pulse repetition rate of 100 Hz are presented in the paper as well. Energy efficiency of the antenna is 0.75 at the axial ratio equal to 1.3. The effective potential of radiation of the source at the voltage amplitudes of the bipolar pulse generator equal to -175/+200 kV reaches 280 kV.

  4. Atmospheric Radiation Measurement program climate research facility operations quarterly report.

    SciTech Connect

    Sisterson, D. L.; Decision and Information Sciences

    2006-09-06

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,074.80 hours (0.95 x 2,184 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,965.60 hours (0.90 x 2,184), and that for the Tropical Western Pacific (TWP) locale is 1,856.40 hours (0.85 x 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.80 hours (0.95 x 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive

  5. Atomistic Computational Model of Radiation Damage of Nano-sized Systems in Intense X-ray Pulses

    NASA Astrophysics Data System (ADS)

    Ho, Phay; Jiang, Wei; Lau, Kar Chun; Young, Linda

    2014-05-01

    We present a combined Monte-Carlo/molecular- dynamics (MC/MD) computational model that is suitable for monitoring the physics of intense, femtosecond XFEL pulses interacting with complex systems of various sizes, from nanometers to micrometers, and matters of various compositions. In this model, the occurrences of x-ray absorption, ionization, relaxation and electron-impact processes are treated by a MC method, and the subsequent dynamics of the all the electrons, ions and atoms are tracked using an MD method. Our model extends the previous MC/MD model and provides new capabilities to probe the impacts of transient states on radiation damage dynamics. Recently, we have added LAMMPS as the driver of MD dynamics. This is a critical addition as now our code can run on Mira, a new petascale supercomputer with 786K core processors at the Argonne Leadership Computing Facility. Also, it can treat micron-sized systems with trillions of particles and both homogeneous and heterogeneous composition. Using our model, we examine the ionization dynamics of Argon clusters in an XFEL pulse as a function of particle sizes and pulse parameters, and we compare our results with the experimental data. Supported by the Chemical Sciences, Geosciences, and Biosciences Di- vision, Office of Basic Energy Sciences, Office of Science, US Dept of Energy, Contract DE-AC02-06CH11357.

  6. Cross modulation method of transformation of the spatial coherence of pulsed laser radiation in a nonlinear medium

    SciTech Connect

    Kitsak, M A; Kitsak, A I

    2008-04-30

    The cross modulation method of transformation of the spatial coherence of low-power pulsed laser radiation in a nonlinear medium is proposed. The method is realised experimentally in a multimode optical fibre. The estimates of the degree of spatial coherence of radiation subjected to the phase cross modulation demonstrated the high efficiency of this radiation decorrelation mechanism. (control of laser radiation parameters)

  7. Occupational radiation Exposure at Agreement State-Licensed Materials Facilities, 1997-2010

    SciTech Connect

    U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research

    2012-07-07

    The purpose of this report is to examine occupational radiation exposures received under Agreement State licensees. As such, this report reflects the occupational radiation exposure data contained in the Radiation Exposure Information and Reporting System (REIRS) database, for 1997 through 2010, from Agreement State-licensed materials facilities.

  8. Porcine dermal lesions produced by 1540-nm laser radiation pulses

    NASA Astrophysics Data System (ADS)

    Roach, William P.; Johnson, Thomas E.

    2001-07-01

    Completion of recent studies within our group indicates a breed-based difference in dermal response to 1540 nm 0.8 millisecond laser pulses. Laser exposure to Yucatan Mini- Pigs (highly pigmented skin) and Yorkshire pigs (lightly pigmented skin) demonstrate statistical differences between the ED50's of the two breeds. Laser delivery is accomplished using an Er:Glass system producing 1540 nm of light at millisecond exposure times and in the range of 5 to 95 J/cm2. Dermal lesion development was evaluated for acute, 1 hour, and 24-hour post exposure presentation. Our data contradicts the theory that water absorption is the sole mechanism of dermal tissue damage observed from 1540 nm laser exposures, as skin chromophores appear to play a role in lesion development.

  9. Time-dependent quasi-one-dimensional simulations of high enthalpy pulse facilities

    NASA Technical Reports Server (NTRS)

    Wilson, Gregory J.

    1992-01-01

    A numerical methodology is presented for simulating the time-dependent reacting flow inside the entire length of high enthalpy pulse facilities. The methodology is based on a finite-volume TVD scheme for the quasi-1D Euler equations coupled with finite-rate chemistry. A moving mesh and tracking of gas interfaces are used to overcome certain numerical difficulties associated with these types of flows. Simulation results of a helium driven shock tube show that computations can be used to predict the off-tailored behavior of shock tubes and tunnels. Particular attention is given to computations of the flow through the NASA Ames 16-inch combustion driven shock tunnel which show the influence of nonuniformities in the driver section on the reservoir conditions; and the effect of finite secondary diaphragm opening times on the chemical composition of the test flow in the HYPULSE expansion tube.

  10. Lymphoid tissue during irradiation of tumors with pulsing laser's radiation

    NASA Astrophysics Data System (ADS)

    Moskalik, Konstantin G.

    2002-06-01

    The structure of the regional lymph nodes and the thymus was studied in the experiments upon the mice of the line C57BL with the subcutaneous interwoven melanoma B16 in the periods from one hour to 12 days after the radiation of melanoma with one irradiation impulse of the Nd laser with the energy density of 400 J/cm2. During the first 3 days after the irradiation of tumor with laser radiation the impoverishment of lymph nodes and thymus with lymphocytes takes place because of their intensified migration from these organs to the blood channel. Then one can see the restoration of the lymph nodes and thymus structure. The restoration of lymphopoiesis in the lymph nodes went on in the first place because of the poiesis in the follicles which consist of B-lymphocytes. Consequently, the lymphoid tissue plays a great role in the reorganization of the immunological status of the organism. Reorganization can be seen during the treatment of tumors with laser radiation, and it takes place in the first instance because of the reinforcement of the humoral immunity.

  11. Radially polarized, half-cycle, attosecond pulses from laser wakefields through coherent synchrotronlike radiation.

    PubMed

    Li, F Y; Sheng, Z M; Chen, M; Yu, L L; Meyer-ter-Vehn, J; Mori, W B; Zhang, J

    2014-10-01

    Attosecond bursts of coherent synchrotronlike radiation are found when driving ultrathin relativistic electron disks in a quasi-one-dimensional regime of wakefield acceleration, in which the laser waist is larger than the wake wavelength. The disks of overcritical density shrink radially due to focusing wakefields, thus providing the transverse currents for the emission of an intense, radially polarized, half-cycle pulse of about 100 attoseconds in duration. The electromagnetic pulse first focuses to a peak intensity (7×10(20)W/cm(2)) 10 times larger than the driving pulse and then emerges as a conical beam. Basic dynamics of the radiative process are derived analytically and in agreement with particle-in-cell simulations. By making use of gas targets instead of solids to form the ultrathin disks, this method allows for high repetition rates required for applications. PMID:25375611

  12. Enhancement of proton acceleration by frequency-chirped laser pulse in radiation pressure mechanism

    NASA Astrophysics Data System (ADS)

    Vosoughian, H.; Riazi, Z.; Afarideh, H.; Yazdani, E.

    2015-07-01

    The transition from hole-boring to light-sail regime of radiation pressure acceleration by frequency-chirped laser pulses is studied using particle-in-cell simulation. The penetration depth of laser into the plasma with ramped density profile increases when a negatively chirped laser pulse is applied. Because of this induced transparency, the laser reflection layer moves deeper into the target and the hole-boring stage would smoothly transit into the light-sail stage. An optimum chirp parameter which satisfies the laser transparency condition, a 0 ≈ π n e l / n c λ , is obtained for each ramp scale length. Moreover, the efficiency of conversion of laser energy into the kinetic energy of particles is maximized at the obtained optimum condition. A relatively narrow proton energy spectrum with peak enhancement by a factor of 2 is achieved using a negatively chirped pulse compared with the un-chirped pulse.

  13. Free-electron laser at the TESLA Test Facility at DESY: toward a tunable short-pulsed soft x-ray source

    NASA Astrophysics Data System (ADS)

    Gerth, Christopher

    2001-12-01

    A high peak current, low emittance, short pulse electron beam can produce intense, laser-like radiation in a single pass through a long periodic magnetic structure. The construction of such free-electron lasers (FELs) based on self-amplified spontaneous emission (SASE) has become feasible by recent advances in accelerator technologies. Since SASE FELs do not require any optical components they are promising sources for the generation of intense, sub- picosecond laser pulses which are continuously tunable over a wide wavelength range in the vacuum ultraviolet (VUV) and X-ray region. In the first phase of the VUV-FEL (phase I) at the TESLA Test Facility at DESY, SASE was achieved for the first time in the VUV at wavelengths between 80 and 180 nm. The concept of the VUV FEL at DESY and first experimental results are presented. The second phase of the TESLA Test Facility (phase II), which includes an increase of the electron beam energy to 1 GeV, aims at the construction of a SASE FEL operating in the soft X-ray region. An overview of the current status and the activities toward a soft X-ray FEL user facility is given.

  14. Response of nickel surface to pulsed fusion plasma radiations

    SciTech Connect

    Niranjan, Ram Rout, R. K. Srivastava, R. Gupta, Satish C.; Chakravarthy, Y.; Patel, N. N.; Alex, P.

    2014-04-24

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  15. Atmospheric Radiation Measurement Program facilities newsletter, October 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-11-04

    Aerosol Observing System Upgraded--The Aerosol Observing System (AOS) at the SGP central facility recently received maintenance and was upgraded to improve its performance. The AOS measures the properties of the aerosol particles around it. Several AOS components were removed, repaired, and calibrated to operate within specifications. The system continuously gathers information about the way minute aerosol particles interact with solar radiation. A better understanding of these interactions will help climate change researchers integrate aerosol effects more accurately into global climate computer models. Polar Bears Make Work Dangerous at ARM North Slope of Alaska Site--The late development of seasonal sea ice has increased polar bear sitings at ARM's Barrow site. The bears were recently seen next to the ARM instrument towers at Barrow, making the normal work day a bit more tricky for the technicians who are at the site year-round. Polar bears are not afraid of people and will attack and kill. The bears usually spend most of their time on off-shore ice floes hunting seals. This season, a large storm pushed the floes out to sea while the bears were ashore at Barrow, leaving them to forage for food on land until the sea ice reforms with the onset of colder weather. The hungry bears have made working at the Barrow CART site a dangerous proposition. ARM workers carry shotguns with them at all times for protection. On a recent journey to the site, ARM instrument mentor Michael Ritsche encountered the animals. ''You become much more aware of your surroundings,'' said Ritsche after returning safely to Argonne. Barrow residents protect themselves by shooting warning shells to scare the bears away from developed areas. Hearing the firing in the early mornings and late evenings at Barrow reminded Ritsche that he was in a more dangerous world.

  16. Radiation drive with a composite laser pulse shape

    SciTech Connect

    Cobble, J. A.; Tubbs, D. L.; Hoffman, N. M.; Swift, D. C.; Tierney, T.

    2004-01-01

    The objective is to develop a 6-ns Hohlraum environment on Omega for Be anisotropy studies. In particular, they are seeking an environment for Be isotropy studies with enough growth times to assess the suitability of Be for NIF ignition capsules. In 20 shots to date, we have: (1) synchronized 2 laser pulse shapes at Omega to obtain a smooth halfraum drive for {approx}6 ns; (2) characterized the drive with Dante ({approx}180 eV peak); (3) obtained high quality VISAR data (using a mirror); (4) measured ejected Be sample velocity; (5) made the first estimates of Au migration to the axis of the vacuum halfraum; and (6) collected the first face-on x-ray images of sinusoidally perturbed Be samples. The immediate objective is to qualify a target for the Be studies. To that end, we hope: (1) to explore alternate foot drives; (2) optimize the radiography; and (3) to field and characterize gas-filled targets within the next 6 months.

  17. Photon dosimetry using plastic scintillators in pulsed radiation fields

    SciTech Connect

    David L. Chichester; Brandon W. Blackburn; James T. Johnson; Scott W. Watson

    2007-04-01

    Simulations and experiments have been carried out to explore using a plastic scintillator as a dosimetry probe in the vicinity of a pulsed bremsstrahlung source in the range 4 to 20 MeV. Taking advantage of the tissue-equivalent properties of this detector in conjunction with the use of a fast digital signal processor near real-time dosimetry was shown to be possible. The importance of accounting for a broad energy electron beam in bremsstrahlung production, and photon scattering and build-up, in correctly interpreting dosimetry results at long stand-off distances is highlighted by comparing real world experiments with ideal geometry simulations. Close agreement was found between absorbed energy calculations based upon spectroscopic techniques and calculations based upon signal integration, showing a ratio between 10 MeV absorbed dose to 12 MeV absorbed dose of 0.66 at a distance of 91.4 m from the accelerator. This is compared with an idealized model simulation with a monoenergetic electron beam and without scattering, where the ratio was 0.46.

  18. Attosecond Gamma-Ray Pulses via Nonlinear Compton Scattering in the Radiation-Dominated Regime

    NASA Astrophysics Data System (ADS)

    Li, Jian-Xing; Hatsagortsyan, Karen Z.; Galow, Benjamin J.; Keitel, Christoph H.

    2015-11-01

    The feasibility of the generation of bright ultrashort gamma-ray pulses is demonstrated in the interaction of a relativistic electron bunch with a counterpropagating tightly focused superstrong laser beam in the radiation-dominated regime. The Compton scattering spectra of gamma radiation are investigated using a semiclassical description for the electron dynamics in the laser field and a quantum electrodynamical description for the photon emission. We demonstrate the feasibility of ultrashort gamma-ray bursts of hundreds of attoseconds and of dozens of megaelectronvolt photon energies in the near-backwards direction of the initial electron motion. The tightly focused laser field structure and the radiation reaction are shown to be responsible for such short gamma-ray bursts, which are independent of the durations of the electron bunch and of the laser pulse. The results are measurable with the laser technology available in the near future.

  19. Generation of Intense Narrow-Band Tunable Terahertz Radiation from Highly Bunched Electron Pulse Train

    NASA Astrophysics Data System (ADS)

    Li, Heting; Lu, Yalin; He, Zhigang; Jia, Qika; Wang, Lin

    2016-07-01

    We present the analysis and start-to-end simulation of an intense narrow-band terahertz (THz) source with a broad tuning range of radiation frequency, using a single-pass free electron laser (FEL) driven by a THz-pulse-train photoinjector. The fundamental radiation frequency, corresponding to the spacing between the electron microbunches, can be easily tuned by varying the spacing time between the laser micropulses. Since the prebunched electron beam is highly bunched at the first several harmonics, with the harmonic generation technique, the radiation frequency range can be further enlarged by several times. The start-to-end simulation results show that this FEL is capable of generating a few tens megawatts power, several tens micro-joules pulse energy, and a few percent bandwidth at the frequencies of 0.5-5 THz. In addition, several practical issues are considered.

  20. Atmospheric radiation measurement program facilities newsletter, April 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-05-03

    ) Validation Campaign--Researchers from Lawrence Berkeley National Laboratory in California will be deploying instruments at the CART site in May. Portable micrometeorology towers will be used to measure fluxes of carbon dioxide, water, and heat between the surface and the atmosphere. The exchange of these constituents varies with regional climate, soil type, and surface vegetation. Greater knowledge will improve the accuracy of computer models (and hence predictions) of the exchanges. Measurements made with the portable instruments will be compared with measurements being collected by instruments at the central facility. AWS Campaign--The State University of New York at Albany will deploy an oxygen A-band and water vapor band spectrometer (AWS) at the CART site on May 20-June 30, 2001. Measurements made by the AWS will be used to determine absorption of radiation by water vapor within clouds, a quantity important to understanding the behavior of solar radiation as it passes through clouds.

  1. Surface shortwave aerosol radiative forcing during the Atmospheric Radiation Measurement Mobile Facility deployment in Niamey, Niger

    NASA Astrophysics Data System (ADS)

    McFarlane, S. A.; Kassianov, E. I.; Barnard, J.; Flynn, C.; Ackerman, T. P.

    2009-07-01

    The Atmospheric Radiation Measurement (ARM) Program's Mobile Facility (AMF) was deployed to Niamey, Niger, during 2006. Niamey, which is located in sub-Saharan Africa, is affected by both dust and biomass burning emissions. Column aerosol optical properties were derived from multifilter rotating shadowband radiometer, measurements and the vertical distribution of aerosol extinction was derived from a micropulse lidar during the two observed dry seasons (January-April and October-December). Mean aerosol optical depth (AOD) and single scattering albedo (SSA) at 500 nm during January-April were 0.53 ± 0.4 and 0.94 ± 0.05, while during October-December mean AOD and SSA were 0.33 ± 0.25 and 0.99 ± 0.01. Aerosol extinction profiles peaked near 500 m during the January-April period and near 100 m during the October-December period. Broadband shortwave surface fluxes and heating rate profiles were calculated using retrieved aerosol properties. Comparisons for noncloudy periods indicated that the remote sensing retrievals provided a reasonable estimation of the aerosol optical properties, with mean differences between calculated and observed fluxes of less than 5 W m-2 and RMS differences less than 25 W m-2. Sensitivity tests showed that the observed fluxes could be matched with variations of <10% in the inputs to the radiative transfer model. The calculated 24-h averaged SW instantaneous surface aerosol radiative forcing (ARF) was -21.1 ± 14.3 W m-2 and was estimated to account for 80% of the total radiative forcing at the surface. The ARF was larger during January-April (-28.5 ± 13.5 W m-2) than October-December (-11.9 ± 8.9 W m-2).

  2. Applicability of a Bonner Shere technique for pulsed neutron in 120 GeV proton facility

    SciTech Connect

    Sanami, T.; Hagiwara, M.; Iwase, H.; Iwamoto, Y.; Sakamoto, Y.; Nakashima, H.; Arakawa, H.; Shigyo, N.; Leveling, A.F.; Boehnlein, D.J.; Vaziri, K.; /Fermilab

    2008-02-01

    The data on neutron spectra and intensity behind shielding are important for radiation safety design of high-energy accelerators since neutrons are capable of penetrating thick shielding and activating materials. Corresponding particle transport codes--that involve physics models of neutron and other particle production, transportation, and interaction--have been developed and used world-wide [1-8]. The results of these codes have been ensured through plenty of comparisons with experimental results taken in simple geometries. For neutron generation and transport, several related experiments have been performed to measure neutron spectra, attenuation length and reaction rates behind shielding walls of various thicknesses and materials in energy range up to several hundred of MeV [9-11]. The data have been used to benchmark--and modify if needed--the simulation modes and parameters in the codes, as well as the reference data for radiation safety design. To obtain such kind of data above several hundred of MeV, Japan-Fermi National Accelerator Laboratory (FNAL) collaboration for shielding experiments has been started in 2007, based on suggestion from the specialist meeting of shielding, Shielding Aspects of Target, Irradiation Facilities (SATIF), because of very limited data available in high-energy region (see, for example, [12]). As a part of this shielding experiment, a set of Bonner sphere (BS) was tested at the antiproton production target facility (pbar target station) at FNAL to obtain neutron spectra induced by a 120-GeV proton beam in concrete and iron shielding. Generally, utilization of an active detector around high-energy accelerators requires an improvement on its readout to overcome burst of secondary radiation since the accelerator delivers an intense beam to a target in a short period after relatively long acceleration period. In this paper, we employ BS for a spectrum measurement of neutrons that penetrate the shielding wall of the pbar target

  3. Effect of pulse to pulse variation of divergence, pointing and amplitude of copper vapor laser radiations on their second harmonic and sum frequency conversion

    NASA Astrophysics Data System (ADS)

    Prakash, Om; Mahakud, Ramakanta; Nakhe, Shankar V.; Dixit, Sudhir K.

    2013-09-01

    This paper presents the effect of single pulse stability of divergence angle, beam pointing angle and amplitude of green and yellow radiation pulses of an unstable resonator copper vapor laser (CVL) oscillator in the sum frequency (SF) mixing and second harmonic (SH). The conversion efficiency of sum frequency generation was lower compared to second harmonic processes despite larger fundamental power being used in sum frequency experiments. However the net UV power obtained at the sum frequency was higher than both of the second harmonic UV frequencies. Lower sum frequency generation (SFG) conversion efficiency compared to second harmonic generation (SHG) of individual CVL radiation is attributed to difference in single pulse stability of beam pointing, divergence and amplitude fluctuation of both CVL radiations in addition to commonly known fact of spatio-temporal mis-match. At the same fundamental input power, higher SH conversion efficiency of yellow compared to green is attributed to its better single pulse stability of beam pointing and divergence.

  4. Team Update on North American Proton Facilities for Radiation Testing

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Turflinger, Thomas; Haas, Thurman; George, Jeffrey; Moss, Steven; Davis, Scott; Kostic, Andrew; Wie, Brian; Reed, Robert; Guertin, Steven; Wert, Jerry; Foster, Charles

    2016-01-01

    In the wake of the closure of the Indiana University Cyclotron Facility (IUCF), this presentation provides an overview of the options for North American proton facilities. This includes those in use by the aerospace community as well as new additions from the cancer therapy regime. In addition, proton single event testing background is provided for understanding the criteria needed for these facilities for electronics testing.

  5. Development of a facility for probing the structural dynamics of materials with femtosecond X-ray pulses

    NASA Astrophysics Data System (ADS)

    Faatz, B.; Fateev, A. A.; Feldhaus, J.; Floettmann, K.; Tschentscher, T.; Krzywinski, J.; Pflueger, J.; Rossbach, J.; Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

    2001-08-01

    We propose to use Thomson backscattering of far-infrared (FIR) pulses (100-300 μm wavelength range) by a 500 MeV electron beam to generate femtosecond X-rays at the TESLA Test Facility (TTF) at DESY. Using the parameters of the photocathode rf gun and the magnetic bunch compressors of the TESLA Test Facility (TTF), it is shown that electron pulses of 100-fs (FWHM) duration can be generated. Passing the short electron bunches through an undulator (after the conversion point) can provide a FIR high-power source with laser-like characteristics. On the basis of the TTF parameters we expect to produce X-ray pulses with 100-fs duration, an average brilliance of nearly 1013photons s-1 mrad-2 mm-2 per 0.1% BW at a photon energy 50 keV. The total number of Thomson backscattered photons, produced by a single passage of the electron bunch through the mirror focus, can exceed 107 photons/pulse. We also describe the basic ideas for an upgrade to shorter X-ray pulse duration. It is demonstrated that the TTF has the capability of reaching the 1012photons s-1 mrad-2 mm-2 per 0.1% BW brilliance at a ten femtosecond scale pulse duration.

  6. Combination of fiber-guided pulsed erbium and holmium laser radiation for tissue ablation under water

    NASA Astrophysics Data System (ADS)

    Pratisto, Hans; Frenz, Martin; Ith, Michael; Altermatt, Hans J.; Jansen, E. Duco; Weber, Heinz P.

    1996-07-01

    Because of the high absorption of near-infrared laser radiation in biological tissue, erbium lasers and holmium lasers emitting at 3 and 2 mu m, respectively, have been proven to have optimal qualities for cutting or welding and coagulating tissue. To combine the advantages of both wavelengths, we realized a multiwavelength laser system by simultaneously guiding erbium and holmium laser radiation by means of a single zirconium fluoride (ZrF4) fiber. Laser-induced channel formation in water and poly(acrylamide) gel was investigated by the use of a time-resolved flash-photography setup, while pressure transients were recorded simultaneously with a needle hydrophone. The shapes and depths of vapor channels produced in water and in a submerged gel after single erbium and after combination erbium-holmium radiation delivered by means of a 400- mu m ZrF4 fiber were measured. Transmission measurements were performed to determine the amount of pulse energy available for tissue ablation. The effects of laser wavelength and the delay time between pulses of different wavelengths on the photomechanical and photothermal responses of meniscal tissue were evaluated in vitro by the use of histology. It was observed that the use of a short (200- mu s, 100-mJ) holmium laser pulse as a prepulse to generate a vapor bubble through which the ablating erbium laser pulse can be transmitted (delay time, 100 mu s) increases the cutting depth in meniscus from 450 to 1120 mu m as compared with the depth following a single erbium pulse. The results indicate that a combination of erbium and holmium laser radiation precisely and efficiently cuts tissue under water with 20-50- mu m collateral tissue damage. wave, cavitation, channel formation, infrared-fiber-delivery system, tissue damage, cartilage.

  7. Radiation shielding issues for superconducting RF cavity test facility at Fermilab

    SciTech Connect

    Rakhno, I.; /Fermilab

    2006-11-01

    The results of Monte Carlo radiation shielding study performed with the MARS15 code for the final design of the vertical test cryostat facility to be installed in the Industrial Building 1 at Fermilab are presented and discussed.

  8. Temporal-space transforming pulse-shaping system with knife edge apparatus in Shenguang II upgrade facility

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Chen, Shaohe; Ge, Xiaping; Xu, Shizhong; Fan, Dianyuan

    2005-12-01

    The temporal pulse shaping was realized by using temporal-space transforming pulse-shaping system with the own-designed "Knife edge" apparatus, for the first time to our best knowledge, in a large energy laser facility with the output energy of 454.37J. A quasi-square laser pulse with the pulse width of 1.16ns, the rising time of 337ps, the falling time of 360ps, and the temporal filling factor of 81.2% was obtained. It is quite satisfied with the requirement of physical experiment. In addition, the further improvements of our system have been suggested in order to enhance the stability and the flexibility as well as the restoring ability of the temporal-space transforming process.

  9. Time transfer between the Goddard Optical Research Facility and the U.S. Naval Observatory using 100 picosecond laser pulses

    NASA Technical Reports Server (NTRS)

    Alley, C. O.; Rayner, J. D.; Steggerda, C. A.; Mullendore, J. V.; Small, L.; Wagner, S.

    1983-01-01

    A horizontal two-way time comparison link in air between the University of Maryland laser ranging and time transfer equipment at the Goddard Optical Research Facility (GORF) 1.2 m telescope and the Time Services Division of the U.S. Naval Observatory (USNO) was established. Flat mirrors of 25 cm and 30 cm diameter respectively were placed on top of the Washington Cathedral and on a water tower at the Beltsville Agricultural Research Center. Two optical corner reflectors at the USNO reflect the laser pulses back to the GORF. Light pulses of 100 ps duration and an energy of several hundred microjoules are sent at the rate of 10 pulses per second. The detection at the USNO is by means of an RCA C30902E avalanche photodiode and the timing is accomplished by an HP 5370A computing counter and an HP 1000 computer with respect to a 10 pps pulse train from the Master Clock.

  10. Electrical delay line multiplexing for pulsed mode radiation detectors.

    PubMed

    Vinke, Ruud; Yeom, Jung Yeol; Levin, Craig S

    2015-04-01

    Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of scintillation crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO crystal arrays, with crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each crystal could be accurately identified, even in the presence of scintillation light sharing and inter-crystal Compton scatter among neighboring crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ∼243 ps FWHM to ∼272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO crystal array with 3 mm × 3 mm × 20 mm crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO crystal pixel. The method is flexible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors. PMID:25768002

  11. Electrical delay line multiplexing for pulsed mode radiation detectors

    NASA Astrophysics Data System (ADS)

    Vinke, Ruud; Yeom, Jung Yeol; Levin, Craig S.

    2015-04-01

    Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of scintillation crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO crystal arrays, with crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each crystal could be accurately identified, even in the presence of scintillation light sharing and inter-crystal Compton scatter among neighboring crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ∼243 ps FWHM to ∼272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO crystal array with 3 mm × 3 mm × 20 mm crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO crystal pixel. The method is flexible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors.

  12. Electrical delay line multiplexing for pulsed mode radiation detectors

    PubMed Central

    Vinke, Ruud; Yeom, Jung Yeol; Levin, Craig S.

    2015-01-01

    Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of scintillation crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO crystal arrays, with crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each crystal could be accurately identified, even in the presence of scintillation light sharing and inter-crystal Compton scatter among neighboring crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ~ 243 ps FWHM to ~272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO crystal array with 3 mm × 3 mm × 20 mm crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO crystal pixel. The method is exible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors. PMID:25768002

  13. Pulse

    MedlinePlus

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the patient's heart is pumping. ... rate gives information about your fitness level and health.

  14. Coherent propagation of a short polarised radiation pulse in a one-dimensional resonance Bragg grating

    SciTech Connect

    Maimistov, Andrei I; Polikarpov, V V

    2006-09-30

    The propagation of an optical ultrashort pulse in a resonance Bragg grating is considered taking into account the polarisation of electromagnetic radiation. It is assumed that the grating is formed by thin films containing two-level atoms with the triply degenerate upper energy level. The system of equations is derived for the envelopes of electromagnetic pulses counterpropagating in such a grating. In the long-wavelength (continual) approximation, the system of equations generalising the known system for scalar waves is obtained. The solutions corresponding to elliptically (in particular, linearly and circularly) polarised stationary pulses are found. An arbitrary degree of ellipticity is possible only in a medium with a preliminary prepared stage of resonance atoms. (nonlinear optical phenomena)

  15. A real-time kinetic study of luciferase inactivation by pulsed ionizing radiation

    SciTech Connect

    Bell, D.H.; Gould, J.M.; Patterson, L.K.

    1982-06-01

    The real-time kinetics of radiation-induced inactivation of the luminescent firefly luciferase-luciferin system were investigated. A single, microsecond pulse from a Van de Graaff accelerator delivered to the system is sufficient to decrease the luminescence by over 60%. This decrease exhibits exponential behavior and has a half-time of 46 +/- 6 msec. In both steady-state and pulsed studies, the dose dependence of the inactivation is independent of the dose rate. Likewise, the decay kinetics are independent of the dose per pulse. These studies suggest that the enzyme is altered in a way that inteferes with the initial steps of catalysis without affecting the subsequent steps which lead to light emission.

  16. Tunable, high peak power terahertz radiation from optical rectification of a short modulated laser pulse.

    PubMed

    Gordon, Daniel F; Ting, Antonio; Alexeev, Ilya; Fischer, Richard; Sprangle, Phillip; Kapetenakos, Christos A; Zigler, Arie

    2006-07-24

    A new way of generating high peak power terahertz radiation using ultra-short pulse lasers is demonstrated. The optical pulse from a titanium:sapphire laser system is stretched and modulated using a spatial filtering technique to produce a several picosecond long pulse modulated at the terahertz frequency. A collinear type II phase matched interaction is realized via angle tuning in a gallium selenide crystal. Peak powers of at least 1.5 kW are produced in a 5 mm thick crystal, and tunability is demonstrated between 0.7 and 2.0 THz. Simulations predict that 150 kW of peak power can be produced in a 5 mm thick crystal. The technique also allows for control of the terahertz bandwidth. PMID:19516863

  17. Time-resolved resonance Raman spectroscopy of radiation-chemical processes. [Pulsed irradiation

    SciTech Connect

    Tripathi, G.N.R.

    1983-01-01

    A tunable pulsed laser Raman spectrometer for time resolved Raman studies of radiation-chemical processes is described. This apparatus utilizes the state of art optical multichannel detection and analysis techniques for data acquisition and electron pulse radiolysis for initiating the reactions. By using this technique the resonance Raman spectra of intermediates with absorption spectra in the 248-900 nm region, and mean lifetimes > 30 ns can be examined. This apparatus can be used to time resolve the vibrational spectral overlap between transients absorbing in the same region, and to follow their decay kinetics by monitoring the well resolved Raman peaks. For kinetic measurements at millisecond time scale, the Raman technique is preferable over optical absorption method where low frequency noise is quite bothersome. A time resolved Raman study of the pulse radiolytic oxidation of aqueous tetrafluorohydroquinone and p-methoxyphenol is briefly discussed. 15 references, 5 figures.

  18. Generation of 1.5-kW, 1-THz coherent radiation from a gyrotron with a pulsed magnetic field.

    PubMed

    Glyavin, M Yu; Luchinin, A G; Golubiatnikov, G Yu

    2008-01-11

    To cover a so-called terahertz gap in available sources of coherent electromagnetic radiation, the gyrotron with a pulsed solenoid producing up to a 40 T magnetic field has been designed, manufactured, and tested. At a 38.5 T magnetic field, the gyrotron generated coherent radiation at 1.022 THz frequency in 50 musec pulses. The microwave power and energy per pulse were about 1.5 kW and 75 mJ, respectively. Details of the gyrotron design, manufacturing, operation and measurements of output radiation are given. PMID:18232780

  19. Generation of 1.5-kW, 1-THz Coherent Radiation from a Gyrotron with a Pulsed Magnetic Field

    SciTech Connect

    Glyavin, M. Yu.; Luchinin, A. G.; Golubiatnikov, G. Yu.

    2008-01-11

    To cover a so-called terahertz gap in available sources of coherent electromagnetic radiation, the gyrotron with a pulsed solenoid producing up to a 40 T magnetic field has been designed, manufactured, and tested. At a 38.5 T magnetic field, the gyrotron generated coherent radiation at 1.022 THz frequency in 50 {mu}sec pulses. The microwave power and energy per pulse were about 1.5 kW and 75 mJ, respectively. Details of the gyrotron design, manufacturing, operation and measurements of output radiation are given.

  20. Laser stand for irradiation of targets by laser pulses from the Iskra-5 facility at a repetition rate of 100 MHz

    SciTech Connect

    Annenkov, V I; Garanin, Sergey G; Eroshenko, V A; Zhidkov, N V; Zubkov, A V; Kalipanov, S V; Kalmykov, N A; Kovalenko, V P; Krotov, V A; Lapin, S G; Martynenko, S P; Pankratov, V I; Faizullin, V S; Khrustalev, V A; Khudikov, N M; Chebotar, V S

    2009-08-31

    A train of a few tens of high-power subnanosecond laser pulses with a repetition period of 10 ns is generated in the Iskra-5 facility. The laser pulse train has an energy of up to 300 J and contains up to 40 pulses (by the 0.15 intensity level), the single pulse duration in the train being {approx}0.5 ns. The results of experiments on conversion of a train of laser pulses to a train of X-ray pulses are presented. Upon irradiation of a tungsten target, a train of X-ray pulses is generated with the shape of an envelope in the spectral band from 0.18 to 0.28 keV similar to that of the envelope of the laser pulse train. The duration of a single X-ray pulse in the train is equal to that of a single laser pulse. (lasers)

  1. Technical specifications manual for the MARK-1 pulsed ionizing radiation detection system. Volume 1

    SciTech Connect

    Lawrence, R.S.; Harker, Y.D.; Jones, J.L.; Hoggan, J.M.

    1993-03-01

    The MARK-1 detection system was developed by the Idaho National Engineering Laboratory for the US Department of Energy Office of Arms Control and Nonproliferation. The completely portable system was designed for the detection and analysis of intense photon emissions from pulsed ionizing radiation sources. This manual presents the technical design specifications for the MARK-1 detection system and was written primarily to assist the support or service technician in the service, calibration, and repair of the system. The manual presents the general detection system theory, the MARK-1 component design specifications, the acquisition and control software, the data processing sequence, and the system calibration procedure. A second manual entitled: Volume 2: Operations Manual for the MARK-1 Pulsed Ionizing Radiation Detection System (USDOE Report WINCO-1108, September 1992) provides a general operational description of the MARK-1 detection system. The Operations Manual was written primarily to assist the field operator in system operations and analysis of the data.

  2. Effect of electromagnetic pulse transverse inhomogeneity on ion acceleration by radiation pressure

    SciTech Connect

    Lezhnin, K. V.; Kamenets, F. F.; Beskin, V. S.; Kando, M.; Esirkepov, T. Zh.; Bulanov, S. V.

    2015-03-15

    During ion acceleration by radiation pressure, a transverse inhomogeneity of an electromagnetic pulse leads to an off-axis displacement of the irradiated target, limiting the achievable ion energy. This effect is analytically described within the framework of a thin foil target model and with particle-in-cell simulations showing that the maximum energy of the accelerated ions decreases as the displacement from the axis of the target's initial position increases. The results obtained can be applied to the optimization of ion acceleration by the laser radiation pressure with mass-limited targets.

  3. ARTICLES: Physical laws governing the interaction of pulse-periodic CO2 laser radiation with metals

    NASA Astrophysics Data System (ADS)

    Vedenov, A. A.; Gladush, G. G.; Drobyazko, S. V.; Pavlovich, Yu V.; Senatorov, Yu M.

    1985-01-01

    It is shown theoretically and experimentally that the efficiency of welding metals with a pulse-periodic CO2 laser beam of low duty ratio, at low velocities, can exceed that of welding with cw lasers and with electron beams. For the first time an investigation was made of the influence of the laser radiation parameters (energy and frequency) and of the welding velocity on the characteristics of the weld and on the shape of the weldpool. The influence of the laser radiation polarization on the efficiency of deep penetration was analyzed.

  4. Diagnosing Pulsed Power Produced Plasmas with X-ray Thomson Scattering at the Nevada Terawatt Facility

    NASA Astrophysics Data System (ADS)

    Valenzuela, J. C.; Krauland, C.; Mariscal, D.; Krasheninnikov, I.; Beg, F. N.; Wiewior, P.; Covington, A.; Presura, R.; Ma, T.; Niemann, C.; Mabey, P.; Gregori, G.

    2015-11-01

    We present experimental results on X-ray Thomson scattering (XRTS) at the Nevada Terawatt Facility (NTF) to study current driven plasmas. Using the Leopard laser, ~ 30 J and pulse width of 0.8 ns, we generated He- α emission (4.75 keV) from a thin Ti foil. Initial parameter scans showed that the optimum intensity is ~ 1015W/cm2 with a foil thickness of 2 μm for forward X-ray production. Bandwidth measurements of the source, using a HAPG crystal in the Von Hamos configuration, were found to be ΔE/E ~ 0.01. Giving the scattering angle of our experimental setup of 129 degrees and X-ray probing energy, the non-collective regime was accessed. The ZEBRA load was a 3 mm wide, 500 μm thick, and 10 mm long graphite foil, placed at one of the six current return posts. Estimates of the plasma temperature, density and ionization state were made by fitting the scattering spectra with dynamic structure factor calculations based on the random phase approximation for the treatment of charged particle coupling. The work was partially funded by the Department of Energy grant number DE-NA0001995.

  5. Electronic response of graphene to an ultrashort intense terahertz radiation pulse

    NASA Astrophysics Data System (ADS)

    Ishikawa, Kenichi L.

    2013-05-01

    We have recently reported a study (Ishikawa 2010 Phys. Rev. B 82 201402) on a nonlinear optical response of graphene to a normally incident terahertz radiation pulse within the massless Dirac fermion (MDF) picture, where we have derived physically transparent graphene Bloch equations (GBE). Here we extend it to the tight-binding (TB) model and oblique incidence. The derived equations indicate that interband transitions are governed by the temporal variation of the spinor phase along the electron path in the momentum space and predominantly take place when the electron passes near the Dirac point. At normal incidence, the equations for electron dynamics within the TB model can be cast into the same form of GBE as for the MDF model. At oblique incidence, the equations automatically incorporate photon drag and satisfy the continuity equation for electron density. Single-electron dynamics strongly depend on the model and pulse parameters, but the rapid variations are averaged out after momentum-space integration. Direct current remaining after the pulse is generated in graphene irradiated by an intense monocycle terahertz pulse, even if it is linearly polarized and normally incident. The generated current depends on the carrier-envelope phase, pulse intensity and Fermi energy in a complex manner.

  6. Influence of the Vertical Emittance on the Calculability of the Synchrotron Ultraviolet Radiation Facility

    PubMed Central

    Arp, U.

    2002-01-01

    A method to include the influence of the vertical electron beam emittance onto the calculability of synchrotron radiation is introduced. It accounts for the finite vertical size and angular spread of the electron beam through a convolution procedure. The resulting angular spread of synchrotron radiation can differ significantly from the ideal Schwinger result, depending on the conditions. For the Synchrotron Ultraviolet Radiation Facility detailed results on the influence of the electron emittance for total power and polarization calculations are presented.

  7. Stanford Synchrotron Radiation Laboratory 1991 activity report. Facility developments January 1991--March 1992

    SciTech Connect

    Cantwell, K.; St. Pierre, M.

    1992-12-31

    SSRL is a national facility supported primarily by the Department of Energy for the utilization of synchrotron radiation for basic and applied research in the natural sciences and engineering. It is a user-oriented facility which welcomes proposals for experiments from all researchers. The synchrotron radiation is produced by the 3.5 GeV storage ring, SPEAR, located at the Stanford Linear Accelerator Center (SLAC). SPEAR is a fully dedicated synchrotron radiation facility which operates for user experiments 7 to 9 months per year. SSRL currently has 24 experimental stations on the SPEAR storage ring. There are 145 active proposals for experimental work from 81 institutions involving approximately 500 scientists. There is normally no charge for use of beam time by experimenters. This report summarizes the activity at SSRL for the period January 1, 1991 to December 31, 1991 for research. Facility development through March 1992 is included.

  8. Computer and laboratory modeling of radiation-acoustic detector for charged particles pulse beams and plasma parameters measuring

    SciTech Connect

    Kresnin, Yu.A.; Stervoedov, N.G.

    1996-12-31

    Model investigations and laboratory tests of detectors for charged particles pulse beams and plasma parameters measuring are presented. Detector represents combination of classic Faraday cup with electrical way of signal getting and radiation-acoustic meter of pulse beams parameters. Radiation-acoustic meter consists of two parts--thin detector, transparent for beams of high energy particles, and thick detector with full absorption. Ultrasonic oscillations, which arise during interaction of charged particles pulse beams or plasma with detector material, are transformed by piezoelectric detector into electric signals, whose amplitude-frequency and time characteristics functionally depended on beams parameters. All the signals come into microcontroller device Intel MSC51. This device produces calculations of following beam parameters: average energy, pulse charge, pulse currents, density, beam size and pulse time. Calculated characteristics of meter well coincide with experimental measurements, carried out at accelerators in particles energy range from 1 to 100 Mev.

  9. Radiation protection aspects of the operation in a cyclotron facility

    NASA Astrophysics Data System (ADS)

    Silva, P. P. N.; Carneiro, J. C. G. G.

    2014-02-01

    The activated accelerator cyclotron components and the radioisotope production may impact on the personnel radiation exposure of the workers during the routine maintenance and emergency repair procedures and any modification of the equipment. Since the adherence of the principle of ALARA (as low as reasonable achievable) constitutes a major objective of the cyclotron management, it has become imperative to investigate the radiation levels at the workplace and the probable health effects to the worker caused by radiation exposure. The data analysis in this study was based on the individual monitoring records during the period from 2007 to 2011. Monitoring of the workplace was also performed using gamma and neutron detectors to determine the dose rate in various predetermined spots. The results of occupational radiation exposures were analysed and compared with the values established in national standards and international recommendations. Important guidelines have been developed to reduce the individual dose.

  10. School Facilities and Electric and Magnetic Field Radiation.

    ERIC Educational Resources Information Center

    Carr, Richard L.

    1990-01-01

    The possibility that electric and magnetic field radiation poses a health hazard should be recognized during the planning and designing of a school. A preconstruction assessment of possible exposure should be evaluated before the start of construction. (MLF)

  11. Implementation of ultrafast X-ray diffraction at the 1W2B wiggler beamline of Beijing Synchrotron Radiation Facility.

    PubMed

    Sun, Da Rui; Xu, Guang Lei; Zhang, Bing Bing; Du, Xue Yan; Wang, Hao; Li, Qiu Ju; Zhou, Yang Fan; Li, Zhen Jie; Zhang, Yan; He, Jun; Yue, Jun Hui; Lei, Ge; Tao, Ye

    2016-05-01

    The implementation of a laser pump/X-ray probe scheme for performing picosecond-resolution X-ray diffraction at the 1W2B wiggler beamline at Beijing Synchrotron Radiation Facility is reported. With the hybrid fill pattern in top-up mode, a pixel array X-ray detector was optimized to gate out the signal from the singlet bunch with interval 85 ns from the bunch train. The singlet pulse intensity is ∼2.5 × 10(6) photons pulse(-1) at 10 keV. The laser pulse is synchronized to this singlet bunch at a 1 kHz repetition rate. A polycapillary X-ray lens was used for secondary focusing to obtain a 72 µm (FWHM) X-ray spot. Transient photo-induced strain in BiFeO3 film was observed at a ∼150 ps time resolution for demonstration. PMID:27140165

  12. Atmospheric Radiation Measurement Program facilities newsletter, July 2000.

    SciTech Connect

    Sisterson, D. L.; Holdridge, D. J., ed.

    2000-08-03

    For improved safety in and around the ARM SGP CART site, the ARM Program recently purchased and installed an aircraft detection radar system at the central facility near Lamont, Oklahoma. The new system will enhance safety measures already in place at the central facility. The SGP CART site, especially the central facility, houses several instruments employing laser technology. These instruments are designed to be eye-safe and are not a hazard to personnel at the site or pilots of low-flying aircraft over the site. However, some of the specialized equipment brought to the central facility by visiting scientists during scheduled intensive observation periods (IOPs) might use higher-power laser beams that point skyward to make measurements of clouds or aerosols in the atmosphere. If these beams were to strike the eye of a person in an aircraft flying above the instrument, damage to the person's eyesight could result. During IOPs, CART site personnel have obtained Federal Aviation Administration (FAA) approval to temporarily close the airspace directly over the central facility and keep aircraft from flying into the path of the instrument's laser beam. Information about the blocked airspace is easily transmitted to commercial aircraft, but that does not guarantee that the airspace remains completely plane-free. For this reason, during IOPs in which non-eye-safe lasers were in use in the past, ARM technicians watched for low-flying aircraft in and around the airspace over the central facility. If the technicians spotted such an aircraft, they would manually trigger a safety shutter to block the laser beam's path skyward until the plane had cleared the area.

  13. Dependence of diode sensitivity on the pulse rate of delivered radiation

    SciTech Connect

    Jursinic, Paul A.

    2013-02-15

    Purpose: It has been reported that diode sensitivity decreases by as much as 2% when the average dose rate set at the accelerator console was decreased from 600 to 40 MU/min. No explanation was given for this effect in earlier publications. This work is a detailed investigation of this phenomenon: the change of diode sensitivity versus the rate of delivery of dose pulses in the milliseconds and seconds range. Methods: X-ray beams used in this work had nominal energies of 6 and 15 MV and were generated by linear accelerators. The average dose rate was varied from 25 to 600 MU/min, which corresponded to time between microsecond-long dose pulses of 60-2.7 ms, respectively. The dose-per-pulse, dpp, was changed by positioning the detector at different source-to-detector distance. A variety of diodes fabricated by a number of manufacturers were tested in this work. Also, diodes in three different MapCHECKs (Sun Nuclear, Melbourne, FL) were tested. Results: For all diodes tested, the diode sensitivity decreases as the average dose rate is decreased, which corresponds to an increase in the pulse period, the time between radiation pulses. A sensitivity decrease as large as 5% is observed for a 60-ms pulse period. The diode sensitivity versus the pulse period is modeled by an empirical exponential function. This function has a fitting parameter, t{sub eff}, defined as the effective lifetime. The values of t{sub eff} were found to be 1.0-14 s, among the various diodes. For all diodes tested, t{sub eff} decreases as the dpp decreases and is greater for 15 MV than for 6 MV x rays. The decrease in diode sensitivity after 20 s without radiation can be reversed by as few as 60 radiation pulses. Conclusions: A decrease in diode sensitivity occurs with a decrease in the average dose rate, which corresponds to an increase in the pulse period of radiation. The sensitivity decrease is modeled by an empirical exponential function that decreases with an effective lifetime, t{sub eff}, of

  14. Numerical analysis of radiation dynamics in a combined hohlraum in the X-ray opacity experiments on the 'Iskra-5' laser facility

    SciTech Connect

    Bondarenko, S V; Novikova, E A; Dolgoleva, G V

    2014-03-28

    We report the results of numerical analysis of radiation dynamics (laser absorption and X-ray generation) by using SNDLIRA code in a combined box used in the X-ray opacity measurements on the 'Iskra-5' facility (laser radiation wavelength, λ = 0.66 μm; laser pulse duration, τ{sub 0.5} ≈ 0.6 ns; and energy, 900 J). Combined boxes used in these experiments comprised three sections: two illuminators delivering laser radiation and a central diagnostic section with a test sample. We have proposed a scheme for step-by-step calculation of the heating dynamics of the sample under study in a three-section hohlraum. Two designs of a combined box, which differ in the ways the laser radiation is injected, are discussed. It is shown that the axial injection of the beams results in intense secondary laser irradiation of the illuminator edge which leads to its partial disruption and penetration of laser radiation into the central diagnostic section. In this case the sample under study is exposed to additional uncontrolled action of scattered laser radiation. Such an undesirable action may be avoided by using the lateral injection of the beams through four holes on the lateral side of the illuminators. For the latter case we have calculated the heating dynamics for the sample and found an optimal time delay for an X-ray probe pulse. (interaction of laser radiation with matter. laser plasma)

  15. Generation of nonlinear currents and low-frequency radiation upon interaction of a laser pulse with a metal

    SciTech Connect

    Bezhanov, S G; Uryupin, S A

    2013-11-30

    Nonlinear currents slowly varying in time are found in the skin layer of a metal irradiated by short laser pulses. The low-frequency field generated by the nonlinear currents in metal and vacuum is studied. The spectral composition, energy and shape of the low-frequency radiation pulse are described. (nonlinear optical phenomena)

  16. Features of gallstone and kidney stone fragmentation by IR-pulsed Nd:YAG laser radiation

    NASA Astrophysics Data System (ADS)

    Batishche, Sergei A.

    1995-05-01

    It is shown that infra-red ((lambda) equals 1064 nm) long pulse (approximately 100 microsecond(s) ) radiation of YAG:Nd laser, operating in free generation regime, effectively fragments gallstones, urinary calculus and kidney stones. The features of the mechanism of this process are investigated. Laser lithotripsy is nowadays a method widely used for fragmentation of gallstones, urinary calculus and kidney stones. Flashlamp pumped dye lasers of microsecond duration are most often used for such purposes. Nevertheless, there are some reports on lithotripsies with nanosecond duration laser pulses (for example, Q-switched YAG:Nd laser). The mechanism of the laser fragmentation of such stones was supposed to be the next. The laser powerful radiation, delivered through the optical fiber, is absorbed by the material of the stone. As a result of such highly localized energy absorption, dense plasma is formed, which expands. Such plasma and vapor, liquid confined, forms a cavitation bubble. This bubble grows, reaches its most dimension and then collapses on itself in some hundreds of micro seconds. Shock waves generated during the growth and the collapse of these bubbles are the origin of fragmentation of the stone. It is necessary to say that there are rather confined data on the hundreds microsecond laser pulse fragmentation especially what concerns the usage of infra-red (IR) YAG:Nd lasers with long laser pulses. Clearing this problem would result in better understanding of the fragmentation mechanism and it could favor development of simple and more reliable laser systems for lithotripsy. In this work we report about investigation of features of an effective fragmentation of gallstones, urinary calculus and kidney stones under exposure of IR ((lambda) equals 1064 nm) radiation of repetitive YAG:Nd laser working in free generation regime.

  17. Atmospheric Radiation Measurement Program facilities newsletter, April 2000

    SciTech Connect

    Sisterson, D. L.

    2000-05-05

    This issue of the Atmospheric Radiation Measurement Program (ARM Program) monthly newsletter is about the ARM Program goal to improve scientific understanding of the interactions of sunlight (solar radiation) with the atmosphere, then incorporate this understanding into computer models of climate change. To model climate accurately all around the globe, a variety of data must be collected from many locations on Earth. For its Cloud and Radiation Testbed (CART) sites, ARM chose locations in the US Southern Great Plains, the North Slope of Alaska, and the Tropical Western Pacific Ocean to represent different climate types around the world. In this newsletter they consider the North Slope of Alaska site, with locations at Barrow and Atqasuk, Alaska.

  18. Pegasus II experiments and plans for the Atlas pulsed power facility

    SciTech Connect

    Shlachter, J.S.; Adams, P.J.; Atchison, W.L.

    1997-09-01

    Atlas will be a high-energy (36 MJ stored), high-power ({approximately} 10 TW) pulsed power driver for high energy-density experiments, with an emphasis on hydrodynamics. Scheduled for completion in late 1999, Atlas is designed to produce currents in the 40-50 MA range with a quarter-cycle time of 4-5 {mu}s. It will drive implosions of heavy liners (typically 50 g) with implosion velocities exceeding 20 mm/{mu}s. Under these conditions very high pressures and magnetic fields are produced. Shock pressures in the 50 Mbar range and pressures exceeding 10 Mbar in an adiabatic compression will be possible. By performing flux compression of a seed field, axial magnetic fields in the 2000 T range may be achieved. A variety of concepts have been identified for the first experimental campaigns on Atlas. These experiments include Rayleigh-Taylor instability studies, convergent (e.g., Bell-Plesset type) instability studies, material strength experiments at very high strain and strain rate, hydrodynamic flows in 3-dimensional geometries, equation of state measurements along the hugoniot and adiabats, transport and shock propagation in dense strongly-coupled plasmas, and atomic and condensed matter studies employing ultra-high magnetic fields. Experimental configurations, associated physics issues, and diagnostic strategies are all under investigation as the design of the Atlas facility proceeds. Near-term proof-of-principle experiments employing the smaller Pegasus II capacitor bank have been identified, and several of these experiments have not been performed. This paper discusses a number of recent Pegasus II experiments and identifies several areas of research presently planned on Atlas.

  19. Safety training and safe operating procedures written for PBFA (Particle Beam Fusion Accelerator) II and applicable to other pulsed power facilities

    SciTech Connect

    Donovan, G.L.; Goldstein, S.A.

    1986-12-01

    To ensure that work in advancing pulsed power technology is performed with an acceptably low risk, pulsed power research facilities at Sandia National Laboratories must satisfy general safety guidelines established by the Department of Energy, policies and formats of the Environment, Safety, and Health (ES and H) Department, and detailed procedures formulated by the Pulsed Power Sciences Directorate. The approach to safety training and to writing safe operating procedures, and the procedures presented here are specific to the Particle Beam Fusion Accelerator II (PBFA II) Facility but are applicable as guidelines to other research and development facilities which have similar hazards.

  20. A comparative radiation study at ALBA synchrotron facility between Monte Carlo modeling and radiation monitors dosimetry measurements

    NASA Astrophysics Data System (ADS)

    Devienne, A.; Aymerich, N.; García-Fusté, M. J.; Queralt, X.

    2015-11-01

    ALBA is the Spanish synchrotron facility formed with a 3 GeV electron synchrotron accelerator generating bright beams of synchrotron radiation, located in Cerdanyola del Vallès (Spain). The aim of this work is to study the origin of the radiation produced inside and outside the optical hutch of BOREAS beamline, an experimental station dedicated to study the resonant absorption and scattering of the photons. The objective is to characterize the radiation at the beamline, evaluating in particular the solid bremsstrahlung component of the radiation. The results are obtained after comparing radiation monitors detectors data with Monte Carlo modeling (FLUKA), giving the characteristics of the shielding required to consider the outside of the hutch as a public zone.

  1. Nanosecond-pulsed dielectric barrier discharges in Kr/Cl2 for production of ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Gregório, J.; Aubert, X.; Hagelaar, G. J. M.; Puech, V.; Pitchford, L. C.

    2014-02-01

    In this paper, we present a study of nanosecond-pulsed, coaxial dielectric barrier discharges for generation of UV radiation in Kr/Cl2 mixtures with total pressures of 25 and 50 mbar. This study is based on an ensemble of experimental and modeling results and aims to identify the dominant physical mechanisms leading to the production of KrCl* (B state). The emission band of KrCl* is peaked at 222 nm, which is in the wavelength range of interest for applications in microbial decontamination. We find that for the same energy per pulse deposited in the discharge, more UV radiation is emitted at higher pressures where relatively more of the energy deposited in the gas goes into heating the electrons, with less going to heating the ions in the sheath. The Cl2 partial pressure significantly affects the KrCl* time-averaged, spatial profiles, leading to different optimal conditions for average and for peak UV power densities. Model results show that the highest KrCl* number density occurs near the walls and is associated with the development of cathode sheaths during the voltage pulse.

  2. Atmospheric Radiation Measurement Climate Research Facility Annual Report 2006

    SciTech Connect

    LR Roeder

    2005-11-30

    This annual report describes the purpose and structure of the ARM Climate Research Facility and ARM Science programs and presents key accomplishments in 2006. Noteworthy scientific and infrastructure accomplishments in 2006 include: • Collaborating with the Australian Bureau of Meteorology to lead the Tropical Warm Pool-International Cloud Experiment, a major international field campaign held in Darwin, Australia • Successfully deploying the ARM Mobile Facility in Niger, Africa • Developing the new ARM Aerial Vehicles Program (AVP) to provide airborne measurements • Publishing a new finding on the impacts of aerosols on surface energy budget in polar latitudes • Mitigating a long-standing double-Intertropical Convergence Zone problem in climate models using ARM data and a new cumulus parameterization scheme.

  3. Site/Systems Operations, Maintenance and Facilities Management of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site

    SciTech Connect

    Wu, Susan

    2005-08-01

    This contract covered the site/systems operations, maintenance, and facilities management of the DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site.

  4. Single-cycle Terahertz Pulses with >0.2 V/A Field Amplitudes via Coherent Transition Radiation

    SciTech Connect

    Daranciang, Dan; Goodfellow, John; Fuchs, Matthias; Wen, Haidan; Ghimire, Shambhu; Reis, David A.; Loos, Henrik; Fisher, Alan S.; Lindenberg, Aaron M.; /Stanford U. Materials Sci. Dept. /SIMES, Stanford /SLAC, PULSE

    2012-02-15

    We demonstrate terahertz pulses with field amplitudes exceeding 0.2 V/{angstrom} generated by coherent transition radiation. Femtosecond, relativistic electron bunches generated at the Linac Coherent Light Source are passed through a beryllium foil, and the emitted radiation is characterized as a function of the bunch duration and charge. Broadband pulses centered at a frequency of 10 THz with energies of 140 {mu}J are measured. These far-below-bandgap pulses drive a nonlinear optical response in a silicon photodiode, with which we perform nonlinear autocorrelations that yield information regarding the terahertz temporal profile. Simulations of the spatiotemporal profile agree well with experimental results.

  5. Feasibility Study of SSTO Base Heating Simulation in Pulsed-Type Facilities

    NASA Technical Reports Server (NTRS)

    Park, Chung Sik; Sharma, Surendra; Edwards, Thomas A. (Technical Monitor)

    1995-01-01

    A laboratory simulation of the base heating environment of the proposed reusable Single-Stage-To-Orbit vehicle during its ascent flight was proposed. The rocket engine produces CO2 and H2, which are the main combustible components of the exhaust effluent. The burning of these species, known as afterburning, enhances the base region gas temperature as well as the base heating. To determine the heat flux on the SSTO vehicle, current simulation focuses on the thermochemistry of the afterburning, thermophysical properties of the base region gas, and ensuing radiation from the gas. By extrapolating from the Saturn flight data, the Damkohler number for the afterburning of SSTO vehicle is estimated to be of the order of 10. The limitations on the material strengths limit the laboratory simulation of the flight Damkohler number as well as other flow parameters. A plan is presented in impulse facilities using miniature rocket engines which generate the simulated rocket plume by electric ally-heating a H2/CO2 mixture.

  6. Integrated operations of the National Ignition Facility (NIF) optical pulse generation development system

    SciTech Connect

    Browning, D.; Crane, J. K.; Dane, C. B.; Hackel; Henesian, M.; Hopps, N. W.; Martinez, M. D.; Moran, B.; Penko, F.; Rothenberg, J. E.; Wilcox, R. B.

    1998-07-31

    We describe the Optical Pulse Generation (OPG) testbed, which is the integration of the MOR and Preamplifier Development Laboratories. We use this OPG testbed to develop and demonstrate the overall capabilites of the NIF laser system front end. We will present the measured energy and power output, temporal and spatial pulse shaping capability, FM bandwidth and dispersion for beam smoothing, and measurements of the pulse-to-pulse power variation of the OPG system and compare these results with the required system performance specifications. We will discuss the models that are used to predict the system performance and how the OPG output requirements flowdown to the subordinate subsystems within the OPG system.

  7. Effect of distance to radiation treatment facility on use of radiation therapy after mastectomy in elderly women

    SciTech Connect

    Punglia, Rinaa S. . E-mail: rpunglia@lroc.harvard.edu; Weeks, Jane C.; Neville, Bridget A.; Earle, Craig C.

    2006-09-01

    Purpose: We sought to study the effect of distance to the nearest radiation treatment facility on the use of postmastectomy radiation therapy (PMRT) in elderly women. Methods and Materials: Using data from the linked Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we analyzed 19,787 women with Stage I or II breast cancer who received mastectomy as definitive surgery during 1991 to 1999. Multivariable logistic regression was used to investigate the association of distance with receipt of PMRT after adjusting for clinical and sociodemographic factors. Results: Overall 2,075 patients (10.5%) treated with mastectomy received PMRT. In addition to cancer and patient characteristics, in our primary analysis, increasing distance to the nearest radiation treatment facility was independently associated with a decreased likelihood of receiving PMRT (OR 0.996 per additional mile, p = 0.01). Secondary analyses revealed that the decline in PMRT use appeared at distances of more than 25 miles and was statistically significant for those patients living more than 75 miles from the nearest radiation facility (odds of receiving PMRT of 0.58 [95% CI 0.34-0.99] vs. living within 25 miles of such a facility). The effect of distance on PMRT appeared to be more pronounced with increasing patient age (>75 years). Variation in the effect of distance on radiation use between regions of the country and nodal status was also identified. Conclusions: Oncologists must be cognizant of the potential barrier to quality care that is posed by travel distance, especially for elderly patients; and policy makers should consider this fact in resource allocation decisions about radiation treatment centers.

  8. Atmospheric radiation measurement program facilities newsletter, August 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-08-29

    ARM in Australia--The Atmospheric Radiation Measurement (ARM) Program of the U.S. Department of Energy (DOE) has launched its newest Atmospheric Radiation and Cloud Station (ARCS) in Darwin, Australia. This is the fifth research site established since ARM Program inception in 1989. The new Darwin site and two other ARCS sites--on Manus Island and the island of Nauru--are in the Tropical Western Pacific region. The North American sites in the U.S. Southern Great Plains and on the North Slope of Alaska represent two different climate regions. A goal of the ARM Program is to improve understanding of (1) the ways clouds and atmospheric moisture interact with solar radiation and (2) the effects of these interactions on both a local and global climate. Years of collected data are being used to improve computer climate models so that their predictions are more accurate. The new Darwin site is at the Darwin International Airport, adjacent to the Darwin Airport Meteorological Office. The site features state-of-the-art instrumentation used to measure solar radiation and surface radiation balance; cloud parameters; and standard meteorological variables such as temperature, wind speed and direction, atmospheric moisture, precipitation rates, and barometric pressure. A data management system (DMS) consisting of two computer workstations collects, stores, processes, and backs up data from each of the ARCS instruments. Data are transmitted via the Internet to the United States for further processing and archiving with data from the other ARM sites. All ARM data are freely available via the Internet to the public and the worldwide scientific community (http://www.arm.gov/). Operational since April 2002, the Darwin site was officially dedicated on July 30, 2002, by dignitaries from both the United States and Australia. The site is a collaborative effort between DOE and the Australian Bureau of Meteorology's Special Services Unit--the equivalent of the U.S. National Weather Service

  9. Response of air-filled ion chambers to high-intensity radiation pulses

    SciTech Connect

    Plum, M.; Brown, D.

    1993-01-01

    Ion chambers are one of the most popular types of detectors used for beam loss-monitor systems. To provide a foundation for the development of future loss-monitor systems, and to fully characterize the ion chambers in use at LAMPF, we have studied the response of air-filled cylindrical ion chambers to high-intensity, short-duration radiation pulses. The most intense pulses were about 180 rad in 250 ns (the equivalent steady-state dose rate was about 700 Mrad/h). We filled our chambers with nitrogen gas at 760 Torr and air at 600 Torr. The ion chambers were driven into extreme nonlinear response. We hope these data will be used to design loss-monitor systems based on air-filled ion chambers, thus eliminating the need for gas-flow systems and/or airtight ion chambers.

  10. Response of air-filled ion chambers to high-intensity radiation pulses

    SciTech Connect

    Plum, M.; Brown, D.

    1993-06-01

    Ion chambers are one of the most popular types of detectors used for beam loss-monitor systems. To provide a foundation for the development of future loss-monitor systems, and to fully characterize the ion chambers in use at LAMPF, we have studied the response of air-filled cylindrical ion chambers to high-intensity, short-duration radiation pulses. The most intense pulses were about 180 rad in 250 ns (the equivalent steady-state dose rate was about 700 Mrad/h). We filled our chambers with nitrogen gas at 760 Torr and air at 600 Torr. The ion chambers were driven into extreme nonlinear response. We hope these data will be used to design loss-monitor systems based on air-filled ion chambers, thus eliminating the need for gas-flow systems and/or airtight ion chambers.

  11. Radiative Characteristics of the Pulse-Periodic Discharge Plasma Initiated by Runaway Electrons

    NASA Astrophysics Data System (ADS)

    Lomaev, M. I.; Beloplotov, D. V.; Tarasenko, V. F.; Sorokin, D. A.

    2016-07-01

    Results of experimental investigations of amplitude-temporal and spectral characteristics of radiation of a pulse-periodic discharge plasma initiated in nitrogen by runaway electrons are presented. The discharge was initiated by high-voltage nanosecond voltage pulses with repetition frequency of 60 Hz in a sharply inhomogeneous electric field in a gap between the conic potential cathode and the planar grounded aluminum anode. It is established that intensive lines of Al I atoms and Al II atomic ions, lines of N I atoms and N II ions, bands of the first (1+) and second positive (2+) nitrogen systems, as well as bands of cyanogen CN are observed in the emission spectrum of the discharge plasma under the given excitation conditions.

  12. A novel facility for ageing materials with narrow-band ultraviolet radiation exposure

    SciTech Connect

    Kaerhae, Petri; Ruokolainen, Kimmo; Heikkilae, Anu

    2011-02-15

    A facility for exploring wavelength dependencies in ultraviolet (UV) radiation induced degradation in materials has been designed and constructed. The device is essentially a spectrograph separating light from a lamp to spectrally resolved UV radiation. It is based on a 1 kW xenon lamp and a flat-field concave holographic grating 10 cm in diameter. Radiation at the wavelength range 250-500 nm is dispersed onto the sample plane of 1.5 cm in height and 21 cm in width. The optical performance of the device has been characterized by radiometric measurements. Using the facility, test samples prepared of regular newspaper have been irradiated from 1 to 8 h. Color changes on the different locations of the aged samples have been quantified by color measurements. Yellowness indices computed from the color measurements demonstrate the capability of the facility in revealing wavelength dependencies of the material property changes in reasonable time frames.

  13. Formation of a Single Attosecond Pulse via Interaction of Resonant Radiation with a Strongly Perturbed Atomic Transition

    NASA Astrophysics Data System (ADS)

    Antonov, V. A.; Radeonychev, Y. V.; Kocharovskaya, Olga

    2013-05-01

    We propose a technique to form a single few-cycle attosecond pulse from vacuum ultraviolet or extreme ultraviolet radiation via resonant interaction with hydrogenlike atoms, irradiated by a high-intensity far-off-resonant laser field. The laser field strongly perturbs excited atomic energy levels via the Stark effect and ionizes atoms from the excited states. We show that an isolated attosecond pulse can be formed using either a short incident femtosecond pulse of the resonant radiation or a steep front edge of the laser field. We propose an experimental realization of a single subfemtosecond pulse formation at 121.6 nm in atomic hydrogen and a single sub-100 as pulse formation at 13.5 nm in Li2+ plasma.

  14. Stable radiation pressure acceleration of ions by suppressing transverse Rayleigh-Taylor instability with multiple Gaussian pulses

    NASA Astrophysics Data System (ADS)

    Zhou, M. L.; Liu, B.; Hu, R. H.; Shou, Y. R.; Lin, C.; Lu, H. Y.; Lu, Y. R.; Gu, Y. Q.; Ma, W. J.; Yan, X. Q.

    2016-08-01

    In the case of a thin plasma slab accelerated by the radiation pressure of an ultra-intense laser pulse, the development of Rayleigh-Taylor instability (RTI) will destroy the acceleration structure and terminate the acceleration process much sooner than theoretical limit. In this paper, a new scheme using multiple Gaussian pulses for ion acceleration in a radiation pressure acceleration regime is investigated with particle-in-cell simulation. We found that with multiple Gaussian pulses, the instability could be efficiently suppressed and the divergence of the ion bunch is greatly reduced, resulting in a longer acceleration time and much more collimated ion bunch with higher energy than using a single Gaussian pulse. An analytical model is developed to describe the suppression of RTI at the laser-plasma interface. The model shows that the suppression of RTI is due to the introduction of the long wavelength mode RTI by the multiple Gaussian pulses.

  15. INTERACTION OF LASER RADIATION WITH MATTER: Influence of a target on operation of a pulsed CO2 laser emitting microsecond pulses

    NASA Astrophysics Data System (ADS)

    Baranov, V. Yu; Dolgov, V. A.; Malyuta, D. D.; Mezhevov, V. S.; Semak, V. V.

    1987-12-01

    The profile of pulses emitted by a TEA CO2 laser with an unstable resonator changed as a result of interaction of laser radiation with the surface of a metal in the presence of a breakdown plasma. This influence of a target on laser operation and its possible applications in laser processing of materials are analyzed.

  16. Simulation of nanosecond pulsed laser ablation of copper samples: A focus on laser induced plasma radiation

    NASA Astrophysics Data System (ADS)

    Aghaei, M.; Mehrabian, S.; Tavassoli, S. H.

    2008-09-01

    A thermal model for nanosecond pulsed laser ablation of Cu in one dimension and in ambient gas, He at 1 atm, is proposed in which equations concerning heat conduction in the target and gas dynamics in the plume are solved. These equations are coupled to each other through the energy and mass balances at interface between the target and the vapor and also Knudsen layer conditions. By assumption of local thermal equilibrium, Saha-Eggert equations are used to investigate plasma formation. The shielding effect of the plasma, due to photoionization and inverse bremsstrahlung processes, is considered. Bremsstrahlung and blackbody radiation and spectral emissions of the plasma are also investigated. Spatial and temporal distribution of the target temperature, number densities of Cu and He, pressure and temperature of the plume, bremsstrahlung and blackbody radiation, and also spectral emissions of Cu at three wavelengths (510, 516, and 521 nm) are obtained. Results show that the spectral power of Cu lines has the same pattern as CuI relative intensities from National Institute of Standard and Technology. Investigation of spatially integrated bremsstrahlung and blackbody radiation, and also Cu spectral emissions indicates that although in early times the bremsstrahlung radiation dominates the two other radiations, the Copper spectral emission is the dominant radiation in later times. It should be mentioned that the blackbody radiation has the least values in both time intervals. The results can be used for prediction of the optimum time and position of the spectral line emission, which is applicable in some time resolved spectroscopic techniques such as laser induced breakdown spectroscopy. Furthermore, the results suggest that for distinguishing between the spectral emission and the bremsstrahlung radiation, a spatially resolved spectroscopy can be used instead of the time resolved one.

  17. Formation of short high-power laser radiation pulses in excimer mediums

    NASA Astrophysics Data System (ADS)

    Losev, V. F., Sr.; Ivanov, N. G.; Panchenko, Yu. N.

    2007-06-01

    Presently an excimer mediums continue are examined as one of variants for formation of powerful and over powerful pulses of laser radiation with duration from units of nanosecond up to tens femtosecond. The researches on such powerful installations as "NIKE" (USA) and << SUPER ASHURA >>, Japan) proceed in this direction. The main advantage of excimer mediums is the opportunity to work in a frequency mode, absence of restriction on the size of active area, high uniformity of a gas working medium, high efficiency (up to 10 %) and wide spectral range of laser radiation (KrF, XeCl ~ 2nm, XeF (C-A), Xe IICl ~ 50-100 nanometers). Research in area of high quality laser beams formation in excimer mediums and its amplification in high power amplifiers are carried out the long time in Institute of High Current Electronics SB RAS, Tomsk, Russia. The wide aperture XeCl laser system of MELS-4k is used for these investigations. Last time we take part in program on development of high power excimer laser system with a petawatt level of power. This system supposes the formation and amplification high quality laser beams with different pulse duration from units of nanosecond up to tens femtosecond. We research the possibility of laser beams formation in excimer mediums with ps-ns pulse duration having the low noise and divergence near to diffraction limit. In other hand, we are developing the wide aperture XeF(C-A) amplifier with optical pump on base electron accelerator. According to our estimations of the XeF(C-A) amplifier based on the converter of e-beam energy to the Xe II* fluorescence at 172 nm will allow to obtain up to 100 TW peak power in a 30 fs pulse.

  18. Melanin and the cellular effects of ultrashort-pulse, near-infrared laser radiation

    NASA Astrophysics Data System (ADS)

    Glickman, Randolph D.; Kumar, Neeru; Rockwell, Benjamin A.; Noojin, Gary D.; Denton, Michael L.; Stolarski, David J.

    2003-07-01

    Our research into laser bioeffects has increasingly focused on cytotoxic mechanisms affecting genomic expression and programmed cellular stress responses. In the context of DNA damage, we previously reported that more DNA strand breaks were produced in cultured retinal pigment epithelium (RPE) cells exposed to ultrashort pulse, than to CW, near-infrared (NIR) laser radiation. To test the hypothesis that RPE melanin was the cellular chromophore responsible for mediating this damage, the experiments were repeated with a line of human-derived RPE cells that could be grown in culture expressing varying levels of pigmentation. Lightly-pigmented cells were either unexposed, or exposed to the output of a Ti:Sapphire laser producing 810 nm light in mode-locked pulses (48-fsec at 80 MHz), or as CW radiation. Cells were irradiated at 160 W/cm2 or 80 W/cm2 (the estimated ED50 or half-ED50 for a retinal lesion). Immediately following the laser exposure, cells were processed for the comet assay. Longer "comet" tails and larger "comet" areas indicated more DNA strand breaks. In lightly-pigmented RPE cells, the overall comet assay differences among the laser-exposed groups were smaller than those observed in our earlier experiments which utilized highly pigmented primary cells. The comet tail lengths of cells exposed to the mode-locked pulses at the ED50, however, were significantly longer than those of the controls or the CW-exposed cells. The other comet assay parameters examined (tail moment, comet area) did not show consistent differences among the groups. While these results support the involvement of melanin in the ultrashort pulse laser-induced damage to DNA, they do not exclude the involvement of other cellular chromophores. Some preliminary experiments describing other measures of cellular stress responses to laser-induced oxidative stress are described.

  19. Foot-pulse radiation drive necessary for ICF ignition capsule demonstrated on Z generator

    SciTech Connect

    Sanford, T.W.L.; Olson, R.E.; Chandler, G.A.

    1999-07-01

    Implosion and ignition of an indirectly-driven ICF capsule operating near a Fermi-degenerate isentrope requires initial Planckian-radiation-drive temperatures of 70-to-90 eV to be present for a duration of 10-to-15 ns prior to the main drive pulse. Such capsules are being designed for high pulsed-power generators. This foot-pulse drive capability has been recently demonstrated in a NIF-sized ({phi} = 6-mm 1 = 7-mm), gold hohlraum, using a one-sided static-wall hohlraum geometry on the Z generator. The general arrangement utilized nested tungsten-wire arrays of radii (mass) 20 mm (2 mg) and 10 mm (1 mg) that had an axial length of {approximately} 10 mm. The arrays were driven by a peak current of {approximately} 21 MA and were made to implode on a 2-{micro}m-thick Cu annulus (mass = 4.5 mg), which had a radius of 4 mm and was filled with a low-density CH foam, all centered about the z-axis. The gold hohlraum was mounted on axis and above the Cu/foam target. A 2.9-mm-radius axial hole between the top of the target and hohlraum permitted the x-rays generated from the implosion to enter the hohlraum. The radiation within the hohlraum was monitored by viewing the hohlraum through a 3-mm diameter hole on the lateral side of the hohlraum with a suite of diagnostics.The radiation entering the hohlraum was estimated by an additional suite of on-axis diagnostics, in a limited number of separate shots, when the hohlraum was not present. Additionally, the radiation generated outside the Cu annulus was monitored, for all shots, through a 3-mm diameter aperture located on the outside of the current return can. In the full paper, the characteristics of the radiation measured from these diagnostic sets, including the Planckian temperature of the hohlraum and radiation images, will be discussed as a function of the incident wire-array geometry (single vs nested array and array mass), target length (10, or 20 mm), annulus material (Cu, Au, or nothing), and CH-foam-fill density (10

  20. The doppler frequency shift caused by the inhomogeneities of a medium induced by pulses of intense laser radiation

    NASA Astrophysics Data System (ADS)

    Rozanov, N. N.; Kiselev, Al. S.; Kiselev, An. S.

    2008-08-01

    Self-reflection of pulses of intense laser radiation from an inhomogeneity induced by them in a medium with fast optical nonlinearity is analyzed. The reflected radiation is characterized by a considerable Doppler shift and by a signal magnitude that is sufficient for experimental detection.

  1. Parametric study of broadband terahertz radiation generation based on interaction of two-color ultra-short laser pulses

    SciTech Connect

    Moradi, S.; Ganjovi, A.; Shojaei, F.; Saeed, M.

    2015-04-15

    In this work, using a two-dimensional kinetic model based on particle in cell-Monte Carlo collision simulation method, the influence of different parameters on the broadband intense Terahertz (THz) radiation generation via application of two-color laser fields, i.e., the fundamental and second harmonic modes, is studied. These two modes are focused into the molecular oxygen (O{sub 2}) with uniform density background gaseous media and the plasma channels are created. Thus, a broadband THz pulse that is around the plasma frequency is emitted from the formed plasma channel and co-propagates with the laser pulse. For different laser pulse shapes, the THz electric field and its spectrum are both calculated. The effects of laser pulse and medium parameters, i.e., positive and negative chirp pulse, number of laser cycles in the pulse, laser pulse shape, background gas pressure, and exerted DC electric field on THz spectrum are verified. Application of a negatively chirped femtosecond (40 fs) laser pulse results in four times enhancement of the THz pulse energy (2 times in THz electric field). The emission of THz radiation is mostly observed in the forward direction.

  2. Radiative heat transfer in plasma of pulsed high pressure caesium discharge

    NASA Astrophysics Data System (ADS)

    Lapshin, V. F.

    2016-01-01

    Two-temperature many component gas dynamic model is used for the analysis of features of radiative heat transfer in pulsed high pressure caesium discharge plasma. It is shown that at a sufficiently high pressure the radial optical thickness of arc column is close to unit (τR (λ) ∼ 1) in most part of spectrum. In this case radiative heat transfer has not local character. In these conditions the photons which are emitted in any point of plasma volume are absorbed in other point remote from an emission point on considerable distance. As a result, the most part of the electric energy put in the discharge mainly near its axis is almost instantly redistributed on all volume of discharge column. In such discharge radial profiles of temperature are smooth. In case of low pressure, when discharge plasma is optically transparent for own radiation in the most part of a spectrum (τR(λ) << 1), the emission of radiation without reabsorption takes place. Radiative heat transfer in plasma has local character and profiles of temperature have considerable gradient.

  3. A Long-Pulse Spallation Source at Los Alamos: Facility description and preliminary neutronic performance for cold neutrons

    SciTech Connect

    Russell, G.J.; Weinacht, D.J.; Pitcher, E.J.; Ferguson, P.D.

    1998-03-01

    The Los Alamos National Laboratory has discussed installing a new 1-MW spallation neutron target station in an existing building at the end of its 800-MeV proton linear accelerator. Because the accelerator provides pulses of protons each about 1 msec in duration, the new source would be a Long Pulse Spallation Source (LPSS). The facility would employ vertical extraction of moderators and reflectors, and horizontal extraction of the spallation target. An LPSS uses coupled moderators rather than decoupled ones. There are potential gains of about a factor of 6 to 7 in the time-averaged neutron brightness for cold-neutron production from a coupled liquid H{sub 2} moderator compared to a decoupled one. However, these gains come at the expense of putting ``tails`` on the neutron pulses. The particulars of the neutron pulses from a moderator (e.g., energy-dependent rise times, peak intensities, pulse widths, and decay constant(s) of the tails) are crucial parameters for designing instruments and estimating their performance at an LPSS. Tungsten is the reference target material. Inconel 718 is the reference target canister and proton beam window material, with Al-6061 being the choice for the liquid H{sub 2} moderator canister and vacuum container. A 1-MW LPSS would have world-class neutronic performance. The authors describe the proposed Los Alamos LPSS facility, and show that, for cold neutrons, the calculated time-averaged neutronic performance of a liquid H{sub 2} moderator at the 1-MW LPSS is equivalent to about 1/4th the calculated neutronic performance of the best liquid D{sub 2} moderator at the Institute Laue-Langevin reactor. They show that the time-averaged moderator neutronic brightness increases as the size of the moderator gets smaller.

  4. Intracavity phase conjugation of the radiation from a pulsed frequency-selective CO laser

    SciTech Connect

    Ionin, Andrei A; Kotkov, A A; Seleznev, L V; Kurnosov, A K; Napartovich, A P

    2000-04-30

    The temporal dynamics and efficiency of phase-conjugate reflection in the course of intracavity degenerate four-wave mixing of radiation from a pulsed frequency-selective electron-beam-sustained CO laser was investigated experimentally and theoretically. The energy efficiency of the phase-conjugate reflection in the experiments reached 1.5 - 2.5% for a CO laser emitting as a result of one vibrorotational transition, diminishing on expansion of the emission spectrum of the laser. Comparison of the experimental and calculated data indicates the dominant role of the resonance amplitude phase-conjugation mechanism in the active medium of a CO laser. (nonlinear optical phenomena)

  5. Early Test Facilities and Analytic Methods for Radiation Shielding

    SciTech Connect

    Ingersoll, D.T.

    1992-01-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting held in Chicago, Illinois on November 15 20,1992. The meeting is of special significance since it commemorates the 50th anniversary of the first controlled nuclear chain reaction, which occurred, not coincidentally, in Chicago. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting.

  6. Raman distributed temperature measurement at CERN high energy accelerator mixed field radiation test facility (CHARM)

    NASA Astrophysics Data System (ADS)

    Toccafondo, Iacopo; Nannipieri, Tiziano; Signorini, Alessandro; Guillermain, Elisa; Kuhnhenn, Jochen; Brugger, Markus; Di Pasquale, Fabrizio

    2015-09-01

    In this paper we present a validation of distributed Raman temperature sensing (RDTS) at the CERN high energy accelerator mixed field radiation test facility (CHARM), newly developed in order to qualify electronics for the challenging radiation environment of accelerators and connected high energy physics experiments. By investigating the effect of wavelength dependent radiation induced absorption (RIA) on the Raman Stokes and anti-Stokes light components in radiation tolerant Ge-doped multi-mode (MM) graded-index optical fibers, we demonstrate that Raman DTS used in loop configuration is robust to harsh environments in which the fiber is exposed to a mixed radiation field. The temperature profiles measured on commercial Ge-doped optical fibers is fully reliable and therefore, can be used to correct the RIA temperature dependence in distributed radiation sensing systems based on P-doped optical fibers.

  7. Simulations of radiatively-driven implosions on the PBFA-Z facility

    SciTech Connect

    Aubrey, J.B.; Bowers, R.L.; Peterson, D.L.

    1997-11-01

    We have performed two-dimensional calculations of the implosions of thin-walled aluminum cylinders driven by a source of radiation. The source is generated by the stagnation of an imploding plasma liner on to a foam target (dynamic hohlraum or flying radiation case) in the PBFA-Z facility at Sandia National Laboratory in Albuquerque, New Mexico. Both Lagrangian and Eulerian codes are used for the simulations of the compression of the shell by the ablatively-driven main shock.

  8. Simulations of radiatively-driven implosions on the PBFA-Z facility

    SciTech Connect

    Aubrey, Joysree B.; Bowers, Richard L.; Peterson, Darrell L.

    1997-05-05

    We have performed two-dimensional calculations of the implosions of thin-walled aluminum cylinders driven by a source of radiation. The source is generated by the stagnation of an imploding plasma liner on to a foam target (dynamic hohlraum or flying radiation case) in the PBFA-Z facility at Sandia National Laboratory in Albuquerque, New Mexico. Both Lagrangian and Eulerian codes are used for the simulations of the compression of the shell by the ablatively-driven main shock.

  9. Atmospheric Radiation Measurement (ARM) Data from the ARM Aerial Facility

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. ARM data is collected both through permanent monitoring stations and field campaigns around the world. Airborne measurements required to answer science questions from researchers or to validate ground data are also collected. To find data from all categories of aerial operations, follow the links from the AAF information page at http://www.arm.gov/sites/aaf. Tables of information will provide start dates, duration, lead scientist, and the research site for each of the named campaigns. The title of a campaign leads, in turn, to a project description, contact information, and links to the data. Users will be requested to create a password, but the data files are free for viewing and downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  10. MGR COMPLIANCE PROGRAM GUIDANCE PACKAGE FOR RADIATION PROTECTION EQUIPMENT, INSTRUMENTATION AND FACILITIES

    SciTech Connect

    N /A

    2000-02-01

    This Compliance Program Guidance Package identifies the regulatory guidance and industry codes and standards addressing radiation protection equipment, instrumentation, and support facilities considered to be appropriate for radiation protection at the Monitored Geologic Repository (MGR). Included are considerations relevant to radiation monitoring instruments, calibration, contamination control and decontamination, respiratory protection equipment, and general radiation protection facilities. The scope of this Guidance Package does not include design guidance relevant to criticality monitoring, area radiation monitoring, effluent monitoring, and airborne radioactivity monitoring systems since they are considered to be the topics of specific design and construction requirements (i.e., ''fixed'' or ''built-in'' systems). This Guidance Package does not address radiation protection design issues; it addresses the selection and calibration of radiation monitoring instrumentation to the extent that the guidance is relevant to the operational radiation protection program. Radon and radon progeny monitoring instrumentation is not included in the Guidance Package since such naturally occurring radioactive materials do not fall within the NRC's jurisdiction at the MGR.

  11. An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

    SciTech Connect

    Anania, M. P.; Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; Jaroszynski, D. A.; Geer, S. B. van der; Loos, M. J. de; Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A.; Gillespie, W. A.; MacLeod, A. M.

    2014-06-30

    Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 10{sup 6} per shot for a 100 period undulator, with a mean peak brilliance of 1 × 10{sup 18} photons/s/mrad{sup 2}/mm{sup 2}/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs.

  12. Laser ablation of single-crystalline silicon by radiation of pulsed frequency-selective fiber laser

    NASA Astrophysics Data System (ADS)

    Veiko, V. P.; Skvortsov, A. M.; Huynh, C. T.; Petrov, A. A.

    2015-07-01

    We have studied the process of destruction of the surface of a single-crystalline silicon wafer scanned by the beam of a pulsed ytterbium-doped fiber laser radiation with a wavelength of λ = 1062 nm. It is established that the laser ablation can proceed without melting of silicon and the formation of a plasma plume. Under certain parameters of the process (radiation power, beam scan velocity, and beam overlap density), pronounced oxidation of silicon microparticles with the formation of a characteristic loose layer of fine powdered silicon dioxide has been observed for the first time. The range of lasing and beam scanning regimes in which the growth of SiO2 layer takes place is determined.

  13. Radiation field screening in photoconductive antennae studied via pulsed terahertz emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Loata, Gabriel C.; Thomson, Mark D.; Löffler, Torsten; Roskos, Hartmut G.

    2007-12-01

    We report terahertz emission experiments on low-temperature-grown GaAs photoconductive antennae. Two field-screening effects determine the device response: space-charge screening on a long time scale and radiation field screening of the local electric field. This latter effect is the principal cause for saturation of terahertz emission observed when the emitters are driven hard with high-repetition-rate femtosecond laser pulses. We present an equivalent-circuit model consisting of three elements: a resistor with time-dependent conductance (photoswitch), a time-dependent voltage source (space-charge screening), and the antenna impedance (terahertz emission and radiation field screening). The simulations with this voltage divider reproduce the measured data well.

  14. Temporal-space-transforming pulse-shaping system with a knife-edge apparatus for a high-energy laser facility

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Chen, Shaohe; Ge, Xiaping; Xu, Shizhong; Fan, Dianyuan

    2005-09-01

    For the first time to our knowledge, in a high-energy laser facility with an output energy of 454.37 J, by using a temporal-space-transforming pulse-shaping system with our own design of a knife-edge apparatus, we obtained a quasi-square laser pulse.

  15. Atmospheric Radiation Measurement Program facilities newsletter, May 2000.

    SciTech Connect

    Sisterson, D.L.

    2000-06-01

    This month the authors will visit an ARM CART site with a pleasant climate: the Tropical Western Pacific (TWP) CART site, along the equator in the western Pacific Ocean. The TWP locale lies between 10 degrees North latitude and 10 degrees South latitude and extends from Indonesia east-ward beyond the international date line. This area was selected because it is in and around the Pacific warm pool, the area of warm sea-surface temperatures that determine El Nino/La Nina episodes. The warm pool also adds heat and moisture to the atmosphere and thus fuels cloud formation. Understanding the way tropical clouds and water vapor affect the solar radiation budget is a focus of the ARM Program. The two current island-based CART sites in the TWP are in Manus Province in Papua New Guinea and on Nauru Island.

  16. Comparison of a Commonwealth-initiated regional radiation oncology facility in Toowoomba with a Queensland Health facility.

    PubMed

    Poulsen, M; Middleton, M; McQuitty, S; Ramsay, J; Gogna, K; Martin, J; Khoo, E; Wong, W; Fairweather, R; Walpole, E

    2010-08-01

    The aim was to compare a private Commonwealth-initiated regional radiation oncology facility in Toowoomba with a Queensland Health facility (QHF) in Brisbane. The comparison concentrated on staffing, case mix and operational budgets, but was not able to look at changes in access to services. Data were collected from the two facilities from January 2008 to June 2008 inclusive. A number of factors were compared, including case mix, staffing levels, delay times for treatment, research, training and treatment costs. The case mix between the two areas was similar with curative treatments making up just over half the work load in both centres and two-thirds the work being made up of cancers of breast and prostate. Staffing levels were leaner in Toowoomba, especially in the areas of nursing, administration and trial coordinators. Research activity was slightly higher in Toowoomba. The average medicare cost per treatment course was similar in both centres ($5000 per course). Total costs of an average treatment including patient, State and Commonwealth costs, showed a 30% difference in costing favouring Toowoomba. This regional radiation oncology centre has provided state-of-the-art cancer care that is close to home for patients living in the Darling Downs region. Both public and private patients have been treated with modest costs to the patient and significant savings to QH. The case mix is similar to the QHF, and there has been significant activity in clinical research. A paperless working environment is one factor that has allowed staffing levels to be reduced. Ongoing support from Governments are required if private facilities are to participate in important ongoing staff training. PMID:20718918

  17. Engineered and Administrative Safety Systems for the Control of Prompt Radiation Hazards at Accelerator Facilities

    SciTech Connect

    Liu, James C.; Vylet, Vashek; Walker, Lawrence S.; /SLAC

    2007-12-17

    The ANSI N43.1 Standard, currently in revision (ANSI 2007), sets forth the requirements for accelerator facilities to provide adequate protection for the workers, the public and the environment from the hazards of ionizing radiation produced during and from accelerator operations. The Standard also recommends good practices that, when followed, provide a level of radiation protection consistent with those established for the accelerator communities. The N43.1 Standard is suitable for all accelerator facilities (using electron, positron, proton, or ion particle beams) capable of producing radiation, subject to federal or state regulations. The requirements (see word 'shall') and recommended practices (see word 'should') are prescribed in a graded approach that are commensurate with the complexity and hazard levels of the accelerator facility. Chapters 4, 5 and 6 of the N43.1 Standard address specially the Radiation Safety System (RSS), both engineered and administrative systems, to mitigate and control the prompt radiation hazards from accelerator operations. The RSS includes the Access Control System (ACS) and Radiation Control System (RCS). The main requirements and recommendations of the N43.1 Standard regarding the management, technical and operational aspects of the RSS are described and condensed in this report. Clearly some aspects of the RSS policies and practices at different facilities may differ in order to meet the practical needs for field implementation. A previous report (Liu et al. 2001a), which reviews and summarizes the RSS at five North American high-energy accelerator facilities, as well as the RSS references for the 5 labs (Drozdoff 2001; Gallegos 1996; Ipe and Liu 1992; Liu 1999; Liu 2001b; Rokni 1996; TJNAF 1994; Yotam et al. 1991), can be consulted for the actual RSS implementation at various laboratories. A comprehensive report describing the RSS at the Stanford Linear Accelerator Center (SLAC 2006) can also serve as a reference.

  18. Dynamics of laser-induced channel formation in water and influence of pulse duration on the ablation of biotissue under water with pulsed erbium-laser radiation

    NASA Astrophysics Data System (ADS)

    Ith, M.; Pratisto, H.; Altermatt, H. J.; Frenz, M.; Weber, H. P.

    1994-12-01

    The ability to use fiber-delivered erbium-laser radiation for non-contact arthroscopic meniscectomy in a liquid environment was studied. The laser radiation is transmitted through a water-vapor channel created by the leading part of the laser pulse. The dynamics of the channel formation around a submerged fiber tip was investigated with time-resolved flash photography. Strong pressure transients with amplitudes up to a few hundreds of bars measured with a needle hydrophone were found to accompany the channel formation process. Additional pressure transients in the range of kbars were observed after the laser pulse associated with the collapse of the vapor channel. Transmission measurements revealed that the duration the laser-induced channel stays open, and therefore the energy transmittable through it, is substantially determined by the laser pulse duration. The optimum pulse duration was found to be in the range between 250 and 350 µS. This was confirmed by histological evaluations of the laser incisions in meniscus: Increasing the pulse duration from 300 to 800 µs leads to a decrease in the crater depth from 1600 to 300 µm. A comparison of the histological examination after laser treatment through air and through water gave information on the influence of the vapor channel on the ablation efficiency, the cutting quality and the induced thermal damage in the adjacent tissue. The study shows that the erbium laser combined with an adequate fiber delivery system represents an effective surgical instrument liable to become increasingly accepted in orthopedic surgery.

  19. Atmospheric radiation measurement program facilities newsletter, August 1999.

    SciTech Connect

    Sisterson, D.L.

    1999-09-03

    With the end of summer drawing near, the fall songbird migration season will soon begin. Scientists with the ARM Program will be able to observe the onset of the migration season as interference in the radar wind profiler (RWP) data. An RWP measures vertical profiles of wind and temperature directly above the radar from approximately 300 feet to 3 miles above the ground. The RWP accomplishes this by sending a pulse of electromagnetic energy skyward. Under normal conditions, the energy is scattered by targets in the atmosphere. Targets generally consist of atmospheric irregularities such as variations in temperature, humidity, and pressure over relatively short distances. During the spring and fall bird migration seasons, RWP beam signals are susceptible to overflying birds. The radar beams do not harm the birds, but the birds' presence hampers data collection by providing false targets to reflect the RWP beam, introducing errors into the data. Because of the wavelength of the molar beam, the number of individuals, and the small size of songbirds' bodies (compared to the larger geese or hawks), songbirds are quite likely to be sampled by the radar. Migrating birds usually fly with the prevailing wind, making their travel easier. As a result, winds from the south are ''enhanced'' or overestimated in the spring as the migrating birds travel northward, and winds from the north are overestimated in the fall as birds make their way south. This fact is easily confirmed by comparison of RWP wind data to wind data gathered by weather balloons, which are not affected by birds.

  20. High-resolution x-ray imaging of Kα volume radiation induced by high-intensity laser pulse interaction with a copper target

    NASA Astrophysics Data System (ADS)

    Galtier, E.; Moinard, A.; Khattak, F. Y.; Renner, O.; Robert, T.; Santos, J. J.; Beaucourt, C.; Angelo, P.; Tikhonchuk, V.; Rosmej, F. B.

    2012-10-01

    In a proof of principle experiment using the LULI 100-TW laser facility ELFIE, we have demonstrated high spectral and spatial resolution of Kα volume radiation induced by energetic electrons generated by irradiating solid Cu targets with visible (0.53 µm) 350 fs laser pulses. Employing an x-ray spectrometer equipped with the spherically bent crystal of quartz (502) and with an image plate, single shot Cu-Kα radiation was recorded in first-order reflection allowing for a geometrical mapping of the emission induced by hot electrons with a spatial resolution down to 30 µm. The simultaneously achieved high spectral resolution permitted the identification of asymmetries in the Kα1-group emission profile. Data from the shot in which a part of the laser beam was incident at grazing angle to the target surface show a signature of enhanced lateral transport of energetic electrons.

  1. Localized dispersing of ceramic particles in tool steel surfaces by pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Hilgenberg, K.; Behler, K.; Steinhoff, K.

    2014-06-01

    In this paper the capability of a localized laser dispersing technique for changing the material microstructure and the surface topology of steels is discussed. The laser implantation named technique bases on a discontinuous dispersing of ceramic particles into the surface of steels by using pulsed laser radiation. As ceramic particles TiC, WC and TiB2 are used, substrate material is high-alloyed cold working steel (X153CrMoV12). The influence of the laser parameters pulse length and pulse intensity was investigated in a comprehensive parameter study. The gained surface topology and microstructure were evaluated by optical microscopy, energy dispersive X-ray spectroscopy (EDX) and white light interferometry; mechanical properties were analyzed by micro hardness measurement. The experiments reveal that the alignment of separated, elevated, dome-shaped spots on the steel surface is feasible. The geometrical properties as well as the mechanical properties are highly controllable by the laser parameters. The laser implanted spots show a mostly crack-free and pore-free bonding to the substrate material as well as a significant increase of micro hardness.

  2. Pulsed currents carried by whistlers. IV. Electric fields and radiation excited by an electrode

    SciTech Connect

    Stenzel, R.L.; Urrutia, J.M.; Rousculp, C.L.

    1995-04-01

    Electromagnetic properties of current pulses carried by whistler wave packets are obtained from a basic laboratory experiment. While the magnetic field and current density are described in the preceding companion paper (Part III), the present analysis starts with the electric field. The inductive and space charge electric field contributions are separately calculated in Fourier space from the measured magnetic field and Ohm`s law along B{sub 0}. Inverse Fourier transformation yields the total electric field in space and time, separated into rotational and divergent contributions. The space-charge density in whistler wave packets is obtained. The cross-field tensor conductivity is determined. The frozen-in condition is nearly satisfied, {bold E}+{bold v}{sub {ital e}}{times}{bold B}{congruent}0. The dissipation is obtained from Poynting`s theorem. The waves are collisionally damped; Landau damping is negligible. A radiation resistance for the electrode is determined. Analogous to Poynting`s theorem, the transport of helicity is analyzed. Current helicity is generated by a flow of helicity between pulses traveling in opposite directions which carry opposite signs of helicity. Helicity is dissipated by collisions. These observations complete a detailed description of whistler/current pulses which can occur in various laboratory and space plasmas. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  3. Simulations of radiation damage as a function of the temporal pulse profile in femtosecond X-ray protein crystallography.

    PubMed

    Jönsson, H Olof; Tîmneanu, Nicuşor; Östlin, Christofer; Scott, Howard A; Caleman, Carl

    2015-03-01

    Serial femtosecond X-ray crystallography of protein nanocrystals using ultrashort and intense pulses from an X-ray free-electron laser has proved to be a successful method for structural determination. However, due to significant variations in diffraction pattern quality from pulse to pulse only a fraction of the collected frames can be used. Experimentally, the X-ray temporal pulse profile is not known and can vary with every shot. This simulation study describes how the pulse shape affects the damage dynamics, which ultimately affects the biological interpretation of electron density. The instantaneously detected signal varies during the pulse exposure due to the pulse properties, as well as the structural and electronic changes in the sample. Here ionization and atomic motion are simulated using a radiation transfer plasma code. Pulses with parameters typical for X-ray free-electron lasers are considered: pulse energies ranging from 10(4) to 10(7) J cm(-2) with photon energies from 2 to 12 keV, up to 100 fs long. Radiation damage in the form of sample heating that will lead to a loss of crystalline periodicity and changes in scattering factor due to electronic reconfigurations of ionized atoms are considered here. The simulations show differences in the dynamics of the radiation damage processes for different temporal pulse profiles and intensities, where ionization or atomic motion could be predominant. The different dynamics influence the recorded diffracted signal in any given resolution and will affect the subsequent structure determination. PMID:25723927

  4. High Speed Cinematographic Investigations Of The Interaction Of Pulsed Laser Radiation With Liquids

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, Manfred; Wey, Joseph; Baca, Werner

    1983-03-01

    With regard to scientific research and technical applications considerable work has been done for many years in studying the interaction of high power laser radiation with matter in the gaseous, liquid or condensed phase. The present paper is concerned with recent investigations of the impact of powerful CO2 laser pulses on liquid targets. Pulse energies are in the range of several tens of J at power densities up to several 108W/cm2. The absorption of the laser radiation in a thin surface layer leads to rapid heating and vaporization and above certain threshold intensities to the formation of strongly ionized plasmas. In this case high pressures are building up causing even large amounts of liquid material to be ejected. The pressures were determined quantitatively by means of quartz gages. In order to determine the influence of frictional forces two liquids that is water and polyethylene glycol, were investigated at energy densities ranging from about 3 to 15 J/cm4. High-speed cinematographic techniques were used for visualizing these transient phenomena and for obtaining quantitative information on the velocities of the plasma expansion, the vapor clouds, the shockwaves propagating inside the liquids and the ejection of liquid jets or droplets. A rotating-mirror streak camera and a multiple spark camera was operated at the same time. Their recordings could thus be correlated to the laser parameters (energy and power) and to the laser induced pressures that were obtained simultaneously in each shot.

  5. Pulse radiolysis of nucleic acids and their base constituents: Bibliographies on radiation chemistry. XI

    NASA Astrophysics Data System (ADS)

    von Sonntag, Clemens; Ross, Alberta B.

    In the elucidation of the primary processes involved in the free-radical-induced damage to DNA and its subunits, pulse radiolysis proves to be one of the most powerful tools. The first studies data back to 1964. The updating review (C. v. Sonntag, Radiat. Phys. Chem. 1987, 30, 313) which precedes this compilation has placed the emphasis on the more recent developments. It has been felt that a bibliography including the earlier literature on this subject might be helpful for further reading. For this compilation the data stored by the Radiation Chemistry Data Center bibliographic database (1) through 1986 were processed using the SELECT keywords: purines, pyrimidines, nucleotides, nucleosides, nucleic acids and pulse radiolysis. The number of citations found was reduced by about one-third by eliminating privately published symposia papers, theses and papers not strictly relevant to this topic, e.g. on flavins, NADH, one-electron reduction of nitrouracil or the redox potential of isobarbituric acid. On the other hand, a few more papers known to us but not revealed by the keywords were added. The bibliography is arranged in approximately chronological order, references grouped by year of publication. Reviews are collected at the end of the bibliography in a separate section.

  6. Radiation control aspects of the civil construction for a high power free electron laser (FEL) facility

    SciTech Connect

    Dunn, T.; Neil, G.; Stapleton, G.

    1996-12-31

    The paper discusses some of the assumptions and methods employed for the control of ionizing radiation in the specifications for the civil construction of a planned free electron laser facility based on a 200 MeV, 5 mA superconducting recirculation electron accelerator. Consideration is given firstly to the way in which the underlying building configuration and siting aspects were optimized on the basis of the early assumptions of beam loss and radiation goals. The various design requirements for radiation protection are then considered, and how they were folded into an aesthetically pleasing and functional building.

  7. Atmospheric radiation measurement program facilities newsletter, September 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-10-10

    Our Changing Climate--Is our climate really changing? How do we measure climate change? How can we predict what Earth's climate will be like for generations to come? One focus of the Atmospheric Radiation Measurement (ARM) Program is to improve scientific climate models enough to achieve reliable regional prediction of future climate. According to the Environmental Protection Agency (EPA), the global mean surface temperature has increased by 0.5-1.0 F since the late 19th century. The 20th century's 10 warmest years all occurred in the last 15 years of the century, with 1998 being the warmest year of record. The global mean surface temperature is measured by a network of temperature-sensing instruments distributed around the world, including ships, ocean buoys, and weather stations on land. The data from this network are retrieved and analyzed by various organizations, including the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the World Meteorological Organization. Worldwide temperature records date back to 1860. To reconstruct Earth's temperature history before 1860, scientists use limited temperature records, along with proxy indicators such as tree rings, pollen records, and analysis of air frozen in ancient ice. The solar energy received from the sun drives Earth's weather and climate. Some of this energy is reflected and filtered by the atmosphere, but most is absorbed by Earth's surface. The absorbed solar radiation warms the surface and is re-radiated as heat energy into the atmosphere. Some atmospheric gases, called greenhouse gases, trap some of the re-emitted heat, keeping the surface temperature regulated and suitable for sustaining life. Although the greenhouse effect is natural, some evidence indicates that human activities are producing increased levels of some greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Scientists believe that the combustion of fossil fuels is

  8. Investigation into the electromagnetic impulses from long-pulse laser illuminating solid targets inside a laser facility

    NASA Astrophysics Data System (ADS)

    Yi, Tao; Yang, Jinwen; Yang, Ming; Wang, Chuanke; Yang, Weiming; Li, Tingshuai; Liu, Shenye; Jiang, Shaoen; Ding, Yongkun; Xiao, Shaoqiu

    2016-06-01

    Emission of the electromagnetic pulses (EMP) due to laser-target interaction in laser facility had been evaluated using a cone antenna in this work. The microwave in frequencies ranging from several hundreds of MHz to 2 GHz was recorded when long-pulse lasers with several thousands of joules illuminated the solid targets, meanwhile the voltage signals from 1 V to 4 V were captured as functions of laser energy and backlight laser, where the corresponding electric field strengths were obtained by simulating the cone antenna in combination with conducting a mathematical process (Tiknohov Regularization with L curve). All the typical coupled voltage oscillations displayed multiple peaks and had duration of up to 80 ns before decaying into noise and mechanisms of the EMP generation was schematically interpreted in basis of the practical measuring environments. The resultant data were expected to offer basic know-how to achieve inertial confinement fusion.

  9. Radiation shielding for superconducting RF cavity test facility at A0

    SciTech Connect

    Dhanaraj, N.; Ginsburg, C.; Rakhno, I.; Wu, G.; /Fermilab

    2008-11-01

    The results of Monte Carlo radiation shielding study performed with the MARS15 code for the vertical test facility at the A0 north cave enclosure at Fermilab are presented and discussed. The vertical test facility at the A0 north cave is planned to be used for testing 1.3 GHz single-cell superconducting RF cavities with accelerating length of 0.115 m. The operations will be focused on high accelerating gradients--up to 50 MV/m. In such a case the facility can be a strong radiation source [1]. When performing a radiation shielding design for the facility one has to take into account gammas generated due to interactions of accelerated electrons with cavity walls and surroundings (for example, range of 3.7-MeV electrons in niobium is approximately 3.1 mm while the thickness of the niobium walls of such RF cavities is about 2.8 mm). The electrons are usually the result of contamination in the cavity. The radiation shielding study was performed with the MARS15 Monte Carlo code [2]. A realistic model of the source term has been used that describes spatial, energy and angular distributions of the field-emitted electrons inside the RF cavities. The results of the calculations are normalized using the existing experimental data on measured dose rate in the vicinity of such RF cavities.

  10. Simultaneous Spectral Albedo Measurements Near the Atmospheric Radiation Measurement Southern Great Plains (ARM SGP) Central Facility

    SciTech Connect

    Michalsky, Joseph J.; Min, Qilong; Barnard, James C.; Marchand, Roger T.; Pilewskie, Peter

    2003-04-30

    In this study, a data analysis is performed to determine the area-averaged, spectral albedo at ARM's SGP central facility site. The spectral albedo is then fed into radiation transfer models to show that the diffuse discrepancy is diminished when the spectral albedo is used (as opposed to using the broadband albedo).

  11. Irradiation facility at the IBR-2 reactor for investigation of material radiation hardness

    NASA Astrophysics Data System (ADS)

    Bulavin, M.; Cheplakov, A.; Kukhtin, V.; Kulagin, E.; Kulikov, S.; Shabalin, E.; Verkhoglyadov, A.

    2015-01-01

    Description of the irradiation facility and available parameters of the neutron and gamma exposures including the maximal integrated doses are presented in the paper. The research capabilities for radiation hardness tests of materials in high intensity beam of fast neutrons at the IBR-2 reactor of the Joint Institute for Nuclear Research in Dubna (Russia) are outlined.

  12. Irradiation facility at the IBR-2 reactor for investigating material radiation hardness

    NASA Astrophysics Data System (ADS)

    Bulavin, M. V.; Verkhoglyadov, A. E.; Kulikov, S. A.; Kulagin, E. N.; Kukhtin, V. V.; Cheplakov, A. P.; Shabalin, E. P.

    2015-03-01

    A description of the irradiation facility and available parameters of neutron and gamma exposures, including the maximum integrated doses, are presented in the paper. The research capabilities for radiation hardness tests of materials in a high-intensity beam of fast neutrons at the IBR-2 reactor of the Joint Institute for Nuclear Research in Dubna (Russia) are outlined.

  13. Atmospheric Radiation Measurement Climate Research Facility (ACRF Instrumentation Status: New, Current, and Future)

    SciTech Connect

    JW Voyles

    2008-01-30

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  14. Standing up the National Ignition Facility radiation protection program.

    PubMed

    Kohut, Thomas R; Thacker, Rick L; Beale, Richard M; Dillon, Jon T

    2013-06-01

    Operation of the NIF requires a large and varied number of routine and infrequent activities involving contaminated and radioactive systems, both in servicing online equipment and offline refurbishment of components. Routine radiological operations include up to several dozen entries into contaminated systems per day, multiple laboratories refurbishing radiologically impacted parts, handling of tens of curies of tritium, and (eventually) tens of workers spending most of their day working in radiation areas and handling moderately activated parts. Prior to the introduction of radioactive materials and neutron producing experiments (capable of causing activation), very few of the operating staff had any radiological qualifications or experience. To support the full NIF operating program, over 600 radiological workers needed to be trained, and a functional and large-scale radiological protection program needed to be put in place. It quickly became evident that there was a need to supplement the LLNL site radiological protection staff with additional radiological controls technicians and a radiological protection staff within NIF operations to manage day-to-day activities. This paper discusses the approach taken to stand up the radiological protection program and some lessons learned. PMID:23629066

  15. Atmospheric Radiation Measurement Program facilities newsletter, January 2000

    SciTech Connect

    Sisterson, D.L.

    2000-02-16

    The subject of this newsletter is the ARM unmanned aerospace vehicle program. The ARM Program's focus is on climate research, specifically research related to solar radiation and its interaction with clouds. The SGP CART site contains highly sophisticated surface instrumentation, but even these instruments cannot gather some crucial climate data from high in the atmosphere. The Department of Energy and the Department of Defense joined together to use a high-tech, high-altitude, long-endurance class of unmanned aircraft known as the unmanned aerospace vehicle (UAV). A UAV is a small, lightweight airplane that is controlled remotely from the ground. A pilot sits in a ground-based cockpit and flies the aircraft as if he were actually on board. The UAV can also fly completely on its own through the use of preprogrammed computer flight routines. The ARM UAV is fitted with payload instruments developed to make highly accurate measurements of atmospheric flux, radiance, and clouds. Using a UAV is beneficial to climate research in many ways. The UAV puts the instrumentation within the environment being studied and gives scientists direct measurements, in contrast to indirect measurements from satellites orbiting high above Earth. The data collected by UAVs can be used to verify and calibrate measurements and calculated values from satellites, therefore making satellite data more useful and valuable to researchers.

  16. Nuclear reactor pulse tracing using a CdZnTe electro-optic radiation detector

    NASA Astrophysics Data System (ADS)

    Nelson, Kyle A.; Geuther, Jeffrey A.; Neihart, James L.; Riedel, Todd A.; Rojeski, Ronald A.; Ugorowski, Philip B.; McGregor, Douglas S.

    2012-07-01

    CdZnTe has previously been shown to operate as an electro-optic radiation detector by utilizing the Pockels effect to measure steady-state nuclear reactor power levels. In the present work, the detector response to reactor power excursion experiments was investigated. Peak power levels during an excursion were predicted to be between 965 MW and 1009 MW using the Fuchs-Nordheim and Fuchs-Hansen models and confirmed with experimental data from the Kansas State University TRIGA Mark II nuclear reactor. The experimental arrangement of the Pockels cell detector includes collimated laser light passing through a transparent birefringent crystal, located between crossed polarizers, and focused upon a photodiode. The birefringent crystal, CdZnTe in this case, is placed in a neutron beam emanating from a nuclear reactor beam port. After obtaining the voltage-dependent Pockels characteristic response curve with a photodiode, neutron measurements were conducted from reactor pulses with the Pockels cell set at the 1/4 and 3/4 wave bias voltages. The detector responses to nuclear reactor pulses were recorded in real-time using data logging electronics, each showing a sharp increase in photodiode current for the 1/4 wave bias, and a sharp decrease in photodiode current for the 3/4 wave bias. The polarizers were readjusted to equal angles in which the maximum light transmission occurred at 0 V bias, thereby, inverting the detector response to reactor pulses. A high sample rate oscilloscope was also used to more accurately measure the FWHM of the pulse from the electro-optic detector, 64 ms, and is compared to the experimentally obtained FWHM of 16.0 ms obtained with the 10B-lined counter.

  17. Selective excitation of LI2 by chirped laser pulses with all possible interstate radiative couplings.

    PubMed

    Chatterjee, Souvik; Bhattacharyya, S S

    2010-10-28

    We have numerically explored the feasibility and the mechanism of population transfer to the excited E  (1)Σ(g) electronic state of Li(2) from the v=0 level of the ground electronic state X  (1)Σ(g) using the A  (1)Σ(u) state as an intermediate. In this system, the use of transform limited pulses with a frequency difference greater than the maximum Rabi frequency does not produce population transfer when all possible radiative couplings are taken into account. We have employed two synchronous pulses far detuned from the allowed transition frequencies, mainly with the lower frequency pulse positively chirped, and both pulses coupling the successive pair of states, X-A and A-E. The adiabaticity of the process has been investigated by a generalized Floquet calculation in the basis of 12 field dressed molecular states, and the results have been compared with those obtained from the full solution of time dependent Schrödinger equation. The conventional representation of the process in terms of three (or four) adiabatic potentials is not valid. It has been found that for cases of almost complete population transfer in full calculations with the conservation of the vibrational quantum number, adiabatic passage is attained with the 12 state Floquet model but not with the six state model. The agreement between the full calculations and the 12 state Floquet calculations is generally good when the transfer is adiabatic. Another characteristic feature of this work is the gaining of control over the vibrational state preparation in the final electronic state by careful tuning of the laser parameters as well as the chirp rate sign. This causes time dependent changes in the adiabatic potentials and nonadiabatic transfers can be made to occur between them. PMID:21033794

  18. Selective excitation of LI2 by chirped laser pulses with all possible interstate radiative couplings

    NASA Astrophysics Data System (ADS)

    Chatterjee, Souvik; Bhattacharyya, S. S.

    2010-10-01

    We have numerically explored the feasibility and the mechanism of population transfer to the excited E Σ1g electronic state of Li2 from the v =0 level of the ground electronic state X Σ1g using the A Σ1u state as an intermediate. In this system, the use of transform limited pulses with a frequency difference greater than the maximum Rabi frequency does not produce population transfer when all possible radiative couplings are taken into account. We have employed two synchronous pulses far detuned from the allowed transition frequencies, mainly with the lower frequency pulse positively chirped, and both pulses coupling the successive pair of states, X-A and A-E. The adiabaticity of the process has been investigated by a generalized Floquet calculation in the basis of 12 field dressed molecular states, and the results have been compared with those obtained from the full solution of time dependent Schrödinger equation. The conventional representation of the process in terms of three (or four) adiabatic potentials is not valid. It has been found that for cases of almost complete population transfer in full calculations with the conservation of the vibrational quantum number, adiabatic passage is attained with the 12 state Floquet model but not with the six state model. The agreement between the full calculations and the 12 state Floquet calculations is generally good when the transfer is adiabatic. Another characteristic feature of this work is the gaining of control over the vibrational state preparation in the final electronic state by careful tuning of the laser parameters as well as the chirp rate sign. This causes time dependent changes in the adiabatic potentials and nonadiabatic transfers can be made to occur between them.

  19. X-ray lasing upon two-pulse irradiation of targets on the picosecond SOKOL-P facility

    SciTech Connect

    Andriyash, Aleksandr V; Vikhlyaev, D A; Gavrilov, D S; Dmitrov, D A; Zapysov, A L; Kakshin, A G; Loboda, E A; Lykov, V A; Magda, E P; Politov, V Yu; Potapov, A V; Pronin, V A; Rykovanov, G N; Sukhanov, V N; Tishchenko, A S; Ugodenko, A A; Chefonov, O V

    2006-06-30

    The results of experimental studies of the X-ray lasing on the 3p-3s transitions of neon-like titanium ions are presented. The laser radiation at 1.054 {mu}m was focused to a {approx}30-{mu}m wide line of length from 2 to 8 mm. Plane polished titanium plates were successively irradiated by two pulses: a 400-ps prepulse and a 4-ps main pump pulse delayed by 1.5 ns relative to the prepulse. The total laser energy was 8-10 J. The nanosecond-to-picosecond pulse energy ratio was maintained constant and was equal to 1:3. For a short target length (from 2 to 4 mm), the 326-A line intensity was experimentally observed to grow exponentially with length. The small-signal gain for the X-ray laser radiation is estimated at approximately 30 cm{sup -1}. The X-ray laser beam divergence was equal to about 9 mrad. (lasers)

  20. FY05 LDRD Final ReportTime-Resolved Dynamic Studies using Short Pulse X-Ray Radiation

    SciTech Connect

    Nelson, A; Dunn, J; van Buuren, T; Budil, K; Sadigh, B; Gilmer, G; Falcone, R; Lee, R; Ng, A

    2006-02-10

    Established techniques must be extended down to the ps and sub-ps time domain to directly probe product states of materials under extreme conditions. We used short pulse ({le} 1 ps) x-ray radiation to track changes in the physical properties in tandem with measurements of the atomic and electronic structure of materials undergoing fast laser excitation and shock-related phenomena. The sources included those already available at LLNL, including the picosecond X-ray laser as well as the ALS Femtosecond Phenomena beamline and the SSRL based sub-picosecond photon source (SPPS). These allow the temporal resolution to be improved by 2 orders of magnitude over the current state-of-the-art, which is {approx} 100 ps. Thus, we observed the manifestations of dynamical processes with unprecedented time resolution. Time-resolved x-ray photoemission spectroscopy and x-ray scattering were used to study phase changes in materials with sub-picosecond time resolution. These experiments coupled to multiscale modeling allow us to explore the physics of materials in high laser fields and extreme non-equilibrium states of matter. The ability to characterize the physical and electronic structure of materials under extreme conditions together with state-of-the-art models and computational facilities will catapult LLNL's core competencies into the scientific world arena as well as support its missions of national security and stockpile stewardship.

  1. Atmospheric Radiation Measurement Program facilities newsletter, November 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-12-03

    Fall 2002 Intensive Operation Periods: Single Column Model and Unmanned Aerospace Vehicle--In an Intensive Operation Period (IOP) on November 3-23, 2002, researchers at the SGP CART site are collecting a detailed data set for use in improving the Single Column Model (SCM), a scaled-down climate model. The SCM represents one vertical column of air above Earth's surface and requires less computation time than a full-scale global climate model. Researchers first use the SCM to efficiently improve submodels of clouds, solar radiation transfer, and atmosphere-surface interactions, then implement the results in large-scale global models. With measured values for a starting point, the SCM predicts atmospheric variables during prescribed time periods. A computer calculates values for such quantities as the amount of solar radiation reaching the surface and predicts how clouds will evolve and interact with incoming light from the sun. Researchers compare the SCM's predictions with actual measurements made during the IOP, then adjust the submodels to make predictions more reliable. A second IOP conducted concurrently with the SCM IOP involves high-altitude, long-duration aircraft flights. The original plan was to use an unmanned aerospace vehicle (UAV), but the National Aeronautics and Space Administration (NASA) aircraft Proteus will be substituted because all UAVs have been deployed elsewhere. The UAV is a small, instrument-equipped, remote-control plane that is operated from the ground by a computer. The Proteus is a manned aircraft, originally designed to carry telecommunications relay equipment, that can be reconfigured for uses such as reconnaissance and surveillance, commercial imaging, launching of small space satellites, and atmospheric research. The plane is designed for two on-board pilots in a pressurized cabin, flying to altitudes up to 65,000 feet for as long as 18 hours. The Proteus has a variable wingspan of 77-92 feet and is 56 feet long. The plane can carry

  2. Design and Realization of the Control and Measurement System of the Long Pulsed High Magnetic Field Facility Supplied by Battery

    NASA Astrophysics Data System (ADS)

    Xie, J. F.; Xiong, Y. D.; Han, X. T.; Ding, T. H.; Shi, J. T.; Li, L.

    2013-03-01

    A Control and Measurement System (CMS) is designed to ensure the reliable operation in the long pulsed high magnetic field facility supplied by lead-acid batteries. The CMS is mainly composed of a Programmable Logic Controller (PLC), a fault monitor and protection circuit, a signal processing and data acquisition unit, a local triggering sequence generator and the main control program. The system architecture and kernel parts of the CMS are analyzed and described in detail. The results prove that the designed CMS could perform efficiently and reliably.

  3. Atmospheric radiation measurement program facilities newsletter, August 2001.

    SciTech Connect

    Holdridge, D. J.,ed.

    2001-09-04

    need to be addressed promptly. Sunburn is something most of us have experienced. Severe burns can be dangerous and should be treated by a physician. Heat cramps (painful muscle cramps, usually of the leg muscles) are typically accompanied by heavy sweating. Heat exhaustion symptoms include sweating; weakness; cold, pale, clammy skin; fainting; and vomiting. Heat stroke (also called sunstroke), the most serious heat disorder, can cause the body temperature to rise to 106 F or higher. The skin becomes hot and dry, and the pulse is rapid. Heat stroke is a severe medical emergency and can be fatal. Everyone can take common-sense precautions to ease the danger of a heat wave. Reduce strenuous exercise and outdoor activities. Reschedule these activities for a cooler time of day or move them to an air-conditioned indoor location. Wear lightweight, light-colored clothing to help maintain a normal body temperature and reflect sunlight and heat. Drink plenty of non-alcoholic fluids, especially water, to help maintain good hydration, and eat light meals. Stay out of the sun if possible and spend time in air-conditioned places to reduce the stress of summer heat.

  4. Atmospheric Radiation Measurement Program facilities newsletter, October 2000.

    SciTech Connect

    Sisterson, D. L.

    2000-11-09

    Energy Balance Bowen Ratio System--Estimates of surface energy fluxes are a primary product of the data collection systems at the ARM SGP CART site. Surface fluxes tell researchers a great deal about the effects of interactions between the sun's energy and Earth. Surface fluxes of latent and sensible heat can be estimated by measuring temperature and relative humidity gradients across a vertical distance. Sensible heat is what we feel coming from a warm sidewalk or a metal car door; it can be measured with a thermometer. Latent heat, on the other hand, is released or absorbed during transformations such as the freezing of water into ice or the evaporation of morning dew from a lawn. Such a transformation is referred to as a ''phase change,'' the conversion of a substance among its solid, liquid, and vapor phases. Phase change is an important aspect of our climate. Earth's water cycle abounds with phase changes: rain falls and evaporates, changing from liquid to vapor; the water vapor in the air condenses to form clouds, changing from a gas into a liquid cloud droplet, and eventually falls to Earth's surface as rain or snow; snow falls and melts to liquid or sublimes directly to water vapor. This cyclic process has no end. Surface vegetation and land use play extremely important roles in surface energy fluxes. Plants absorb and reflect solar radiation and also take up water and expel water vapor. The type of plant material, its stage of growth, and its color determine whether and to what extent the surface and air can couple and exchange energy.

  5. ANKA, a customer-oriented synchrotron radiation facility for microfabrication and analytical services

    NASA Astrophysics Data System (ADS)

    Pea Anka Project Group; Buth, G.; Doyle, S.; Einfeld, D.; Hagelstein, M.; Hermle, S.; Huttel, E.; Krüssel, A.; Lange, M.; Mathis, Y.-L.; Mexner, W.; Moser, H. O.; Pellegrin, E.; Ristau, U.; Rossmanith, R.; Schaper, J.; Schieler, H.; Simon, R.; Steininger, R.; Voigt, S.; Walther, R.; Perez, F.; Pont, M.; Plesko, M.

    1998-03-01

    ANKA (Angströmquelle Karlsruhe) is a state-of-the-art synchrotron radiation facility under construction at the Forschungszentrum Karlsruhe. Based on a 2.5 GeV electron storage ring it will deliver photons predominantly in the hard X-ray range but it will also feature both XUV and infrared beamlines. In its first operational phase the radiation will be taken out of normal-conducting dipole bending magnets, while five free long straight sections are foreseen to accommodate insertion devices later on. ANKA has a novel mission, namely to provide synchrotron-radiation based services to industrial and other customers, in the fields of microfabrication and materials analysis. A limited liability company, ANKA GmbH, is being founded to operate the facility. Although commercial services to customers will represent more than half of the overall activity, these services will be complemented by providing beam time for research users.

  6. Optimization Studies for Radiation Shielding of a Superconducting RF Cavity Test Facility

    SciTech Connect

    Ginsburg, Camille M.; Rakhno, Igor; /Fermilab

    2010-07-09

    Test facilities for high-gradient superconducting RF cavities must be shielded for particle radiation, which is generated by field emitted electrons in the cavities. A major challenge for the shielding design is associated with uncertainty in modeling the field emission. In this work, a semi-empirical method that allows us to predict the intensity of the generated field emission is described. Spatial, angular and energy distributions of the generated radiation are calculated with the FISHPACT code. The Monte Carlo code MARS15 is used for modeling the radiation transport in matter. The detailed distributions of the generated field emission are used for studies with 9-cell 1.3 GHz superconducting RF cavities in the Fermilab Vertical Cavity Test Facility. This approach allows us to minimize the amount of shielding inside cryostat which is an essential operational feature.

  7. Dose measurements in pulsed radiation fields with commercially available measuring components.

    PubMed

    Friedrich, Sabrina; Hupe, Oliver

    2016-03-01

    Dose measurements in pulsed radiation fields with dosemeters using the counting technique are known to be inappropriate. Therefore, there is a demand for a portable device able to measure the dose in pulsed radiation fields. As a detector, ionisation chambers seem to be a good alternative. In particular, using a secondary standard ionisation chamber in combination with a reliable charge-measuring system would be a good solution. The Physikalisch-Technische Bundesanstalt (PTB) uses secondary standard ionisation chambers in combination with PTB-made measuring electronics for dose measurements at its reference fields. However, for general use, this equipment is too complex. For measurements on-site, a mobile special electronic system [Hupe, O. and Ankerhold, U. Determination of ambient and personal dose equivalent for personnel and cargo security screening. Radiat. Prot. Dosim. 121: (4), 429-437 (2006)] has been used successfully. Still, for general use, there is a need for a much simpler but a just as good solution. A measuring instrument with very good energy dependence for H*(10) is the secondary standard ionisation chamber HS01. An easy-to-use and commercially available electrometer for measuring the generated charges is the UNIDOS by PTW Freiburg. Depending on the expected dose values, the ionisation chamber used can be selected. In addition, measurements have been performed by using commercially available area dosemeters, e.g. the Mini SmartION 2120S by Thermo Scientific, using an ionisation chamber and the Szintomat 6134 A/H by Automess, using a scintillation detector. PMID:26056377

  8. Whistler wave radiation from a pulsed loop antenna located in a cylindrical duct with enhanced plasma density

    SciTech Connect

    Kudrin, Alexander V.; Shkokova, Natalya M.; Ferencz, Orsolya E.; Zaboronkova, Tatyana M.

    2014-11-15

    Pulsed radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is studied. The radiated energy and its distribution over the spatial and frequency spectra of the excited waves are derived and analyzed as functions of the antenna and duct parameters. Numerical results referring to the case where the frequency spectrum of the antenna current is concentrated in the whistler range are reported. It is shown that under ionospheric conditions, the presence of an artificial duct with enhanced density can lead to a significant increase in the energy radiated from a pulsed loop antenna compared with the case where the same source is immersed in the surrounding uniform magnetoplasma. The results obtained can be useful in planning active ionospheric experiments with pulsed electromagnetic sources operated in the presence of artificial field-aligned plasma density irregularities that are capable of guiding whistler waves.

  9. INTERACTION OF LASER RADIATION WITH MATTER: Influence of surface breakdown on the process of drilling metals with pulsed CO2 laser radiation

    NASA Astrophysics Data System (ADS)

    Arutyunyan, R. V.; Baranov, V. Yu; Bobkov, I. V.; Bol'shov, Leonid A.; Dolgov, V. A.; Kanevskiĭ, M. F.; Malyuta, D. D.; Mezhevov, V. S.

    1988-03-01

    A report is given of the influence of low-threshold surface optical breakdown, occurring under the action of short (~ 5-μs) radiation pulses from a CO2 laser, on the process of the laser drilling of metals. Data are given on the difference between the interaction of radiation pulses having the same duration but differing in shape. A study was made of the influence of the pressure of the atmosphere surrounding a target on the results of laser drilling of metals. A theoretical explanation is given of the experimental results.

  10. Gamma radiation monitoring at the Eastern North Atlantic (ENA), Graciosa Island ARM facility

    NASA Astrophysics Data System (ADS)

    Barbosa, Susana; Miranda, Pedro; Azevedo, Eduardo B.; Nitschke, Kim

    2016-04-01

    Continuous monitoring of gamma radiation is often performed in nuclear facilities and industrial environments as a way to control the ambient radioactivity and give warning of potential accidents. However, gamma radiation is also ubiquitous in the natural environment. The main sources are i) cosmic radiation from space, including secondary radiation from the interaction with atoms in the atmosphere, ii) terrestrial sources from mineral grains in soils and rocks, particularly Potassium (K-40), Uranium (U-238) and Thorium (Th-232) and their decay products (e.g. Radium, Ra-226) , and iii) airborne Radon gas (Rn-222), which is the dominant source of natural environmental radioactivity. The temporal variability of this natural radiation background needs to be well understood and quantified in order to discriminate non-natural sources of radiation in the environment and artificial radionuclides contamination. To this end, continuous gamma radiation monitoring is being performed at the Eastern North Atlantic (ENA) facility located in the Graciosa island (Azores, 39N; 28W), a fixed site of the Atmospheric Radiation Measurement programme (ARM), established and supported by the Department of Energy (DOE) of the United States of America with the collaboration of the local government and University of the Azores. The site is unique for the study of the natural radioactivity background on one hand due to the remote oceanic geographical location, in the middle of the North Atlantic Ocean and clear of direct continental influence, and on the other hand because of the comprehensive dataset of atmospheric parameters that is available for enhancing the interpretation of the radiation measurements, as a result of the vast array of very detailed and high-quality atmospheric measurements performed at the ARM-ENA facility. Gamma radiation in the range 475 KeV to 3000 KeV is measured continuously with a 3" x 3" NaI(Tl) scintillator. The campaign started started in May 2015, with gamma

  11. Generation of low-frequency nonlinear currents in plasma by an ultrashort pulse of high-frequency radiation

    SciTech Connect

    Grishkov, V. E.; Uryupin, S. A.

    2015-07-15

    A kinetic theory of low-frequency currents induced in plasma by an ultrashort high-frequency radiation pulse is developed. General expressions for the currents flowing along the propagation direction of the pulse and along the gradient of the field energy density are analyzed both analytically and numerically for pulse durations longer or shorter than or comparable with the electron collision time in plasma. It is demonstrated that the nonlinear current flowing along the gradient of the field energy density can be described correctly only when the modification of the isotropic part of the electron distribution function is taken into account.

  12. Fast Scintillation Probes For Investigation Of Pulsed Neutron Radiation From Small Fusion Devices

    NASA Astrophysics Data System (ADS)

    Tomaszewski, Krzysztof J.

    2008-04-01

    This paper presents the design as well as laboratory/performance tests results taken by means of the fast scintillation probes. The design of each scintillation probe is based on photomultiplier tube hybrid assembly, which—besides photomultiplier itself—also includes high-voltage divider optimized for recording of fast radiation bursts. Plastic scintillators with short-time response are applied as hard X-ray and neutron radiation detectors. Heavy-duty probe's housing provides efficient shielding against electromagnetic interference and allows carrying out pulsed neutron measurements in a harsh electromagnetic environment. The crucial parameters of scintillation probes have been examined during laboratory tests in which our investigations have been aimed mainly to determine: a time response, an anode radiant sensitivity and an electron transit time dependence on high-voltage supply. During the performance tests, the relative calibration of probes set has been done. It allowed to carry out very accurate measurements of neutron emission anisotropy and investigations of neutron radiation scattering by different materials. The usefulness of presented scintillation probes—embedded in the neutron time-of-flight diagnostic system was proven during experimental campaigns conducted on the plasma-focus PF1000 device.

  13. Radiation defect dynamics in Si at room temperature studied by pulsed ion beams

    SciTech Connect

    Wallace, J. B.; Myers, M. T.; Charnvanichborikarn, S.; Bayu Aji, L. B.; Kucheyev, S. O.; Shao, L.

    2015-10-07

    The evolution of radiation defects after the thermalization of collision cascades often plays the dominant role in the formation of stable radiation disorder in crystalline solids of interest to electronics and nuclear materials applications. Here, we explore a pulsed-ion-beam method to study defect interaction dynamics in Si crystals bombarded at room temperature with 500 keV Ne, Ar, Kr, and Xe ions. The effective time constant of defect interaction is measured directly by studying the dependence of lattice disorder, monitored by ion channeling, on the passive part of the beam duty cycle. The effective defect diffusion length is revealed by the dependence of damage on the active part of the beam duty cycle. Results show that the defect relaxation behavior obeys a second order kinetic process for all the cases studied, with a time constant in the range of ∼4–13 ms and a diffusion length of ∼15–50 nm. Both radiation dynamics parameters (the time constant and diffusion length) are essentially independent of the maximum instantaneous dose rate, total ion dose, and dopant concentration within the ranges studied. However, both the time constant and diffusion length increase with increasing ion mass. This demonstrates that the density of collision cascades influences not only defect production and annealing efficiencies but also the defect interaction dynamics.

  14. Developing Planetary Protection Technology: Microbial Diversity and Radiation Resistance of Microorganisms in a Spacecraft Assembly Facility.

    NASA Astrophysics Data System (ADS)

    Chen, F.; La Duc, M. T.; Baker, A.; Koukol, R.; Barengoltz, J.; Kern, R.; Venkateswaran, K.

    2001-12-01

    Europa has attracted much attention as evidence suggests the presence of a liquid ocean beneath this Jupiter moon's frozen crust. Such an environment might be conducive to the origins of life. Since robotic exploration of Europa is being planned, it becomes crucial to prepare for bio-burden reduction of hardware assembled for Europa missions to avoid contamination of Europa's pristine environment. In this study, we examined the microbial diversity of samples collected from two flight-ready circuit boards and their assembly facility. Also, because Jupiter's strong radiation environment may be able to reduce the viable microbial contamination on flight components, we have also studied the effects of radiation on microbial communities found to be associated with the space-flight hardware and/or present in the assembly facility. Surface samples thought to be representative of considerable human contact were collected from two circuit boards and various locations within the assembly facility using polyester swabs (swab samples). Likewise, sterile wipes were used to sample a shelf above the workstation where the circuit boards were assembled and the floor of the facility (wipe samples). The swab and wipe samples were pooled separately and divided into two halves, one of which was irradiated with 1Mrad gamma radiation for 5.5 hours, the other was not irradiated. About 1.2x104 and 6x104 CFUs/m2 cultivable microbes were detected in the swab and wipe samples, respectively. Radiation proved effective in inhibiting the growth of most microbes. Further characterization of the bacterial colonies observed in the irradiated swab and wipe samples is necessary to determine the degree of the radiation resistance. The16S rDNA sequence analysis of the cultivable microbes indicated that the assembly facility consists mostly of the members of actinobacteria, corynebacteria and pseudomonads. However, the swab samples that include the circuit boards were predominantly populated with

  15. Extremely short pulses via resonantly induced transparency

    NASA Astrophysics Data System (ADS)

    Radeonychev, Y. V.; Polovinkin, V. A.; Kocharovskaya, O.

    2011-07-01

    We study a novel method to produce extremely short pulses of radiation in a resonant medium via induced transparency by means of adiabatic periodic modulation of atomic transition frequencies by far-off-resonant laser field, which causes linear Stark splitting of atomic energy levels resulting in partial transparency of an optically deep medium and drastic spectral modification of an incident resonant radiation. We find the regimes where the output spectrum corresponds to extremely short pulses and discuss several possible experimental realizations of generation of attosecond pulses in Li2+ ions and femtosecond pulses in atomic hydrogen with commercially available facilities.

  16. Prediction of the radiation situation during conditioned radioactive waste storage in hangar-type storage facilities

    NASA Astrophysics Data System (ADS)

    Rosnovskii, S. V.; Bulka, S. K.

    2014-02-01

    An original technology for the conditioning of solidified radioactive waste was developed by the Novovoronezh nuclear power plant (NPP) staff. The technology provides for waste placement inside NZK-150-1.5P containers with their further storage at light hangar-type storage facilities. A number of technical solutions were developed that allow for reducing the gamma-radiation dose rate from the package formed. A methodology for prediction of the radiation situation around hangars, depending on the radiation characteristics of irrecoverable shielding containers (ISCs) located in the peripheral row of a storage facility, was developed with the purpose of assuring safe storage. Based on empirical data, the field background gamma-radiation dose rate at an area as a function of the average dose rate at the hangar surface and the average dose rate close packages, placed in the peripheral row of the storage facility, was calculated. The application of the developed methodology made it possible to reduce by ten times the expenditures for the conditioning and holding of solidified radioactive waste (SRW) while unconditionally providing storage safety.

  17. Operational Radiation Protection in Synchrotron Light and Free Electron Laser Facilities

    SciTech Connect

    Liu, James C.; Rokni, Sayed H.; Vylet, Vaclav; /Jefferson Lab

    2009-12-11

    The 3rd generation synchrotron radiation (SR) facilities are storage ring based facilities with many insertion devices and photon beamlines, and have low injection beam power (< few tens of watts), but extremely high stored beam power ({approx} 1 GW). The 4th generation x-ray free electron laser (FEL) facilities are based on an electron Linac with a long undulator and have high injection beam power (a few kW). Due to its electron and photon beam characteristics and modes of operation, storage ring and photon beamlines have unique safety aspects, which are the main subjects of this paper. The shielding design limits, operational modes, and beam losses are first reviewed. Shielding analysis (source terms and methodologies) and interlocked safety systems for storage ring and photon beamlines (including SR and gas bremsstrahlung) are described. Specific safety issues for storage ring top-off injection operation and FEL facilities are discussed. The operational safety program, e.g., operation authorization, commissioning, training, and radiation measurements, for SR facilities is also presented.

  18. Evaluation of sand as a shielding material for radiation therapy facilities

    SciTech Connect

    Walker, W.J.; Darwish, S.M.; Fitzgerald, L.T.

    1996-06-01

    Radiation protective barriers are designed to ensure that dose equivalent received by any individual does not exceed the applicable maximum permissible value. Materials used conventionally for shielding high energy radiotherapy facilities included concrete, lead, and steel. The choice of a shielding material is dictated by economic factors, the availability of space, and the energy range of the radiation to be attenuated. The use of silica sand to shield Megavoltage teletherapy rooms has only been recently considered for the purpose of lowering construction costs, compared to that of concrete, as well as reducing construction time. This work discusses the design and shielding evaluation of two radiation therapy facilities, which have recently been commissioned, in which the secondary barriers were designed using sand as the shielding material. For these facilities the exterior and interior walls as well as the roof were first constructed using slabs of concrete to form a shell in which sand was poured to fill the space between the slabs. Primary walls for the vault were constructed only of concrete. The sand used had a moisture content of approximately 5% and a density of about 100 lb/ft{sup 3}. In order to minimize settling over time, the sand was poured from a height of about 25 feet so that maximum compacting effect was obtained under gravity. Because of the lack of attenuation data for sand, barrier evaluation has first considered the concrete thickness required to provide adequate shielding, and the equivalent sand thickness was then determined based on the ratio of sand density to that of concrete. Post construction radiation surveys of both facilities have shown that radiation exposure levels are within the permissible limits and they proved that using sand as a shielding material is adequate and prudent.

  19. Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

    SciTech Connect

    Moore, A. S. Graham, P.; Comley, A. J.; Foster, J.; Cooper, A. B. R.; Schneider, M. B.; MacLaren, S.; Lu, K.; Seugling, R.; Satcher, J.; Klingmann, J.; Marrs, R.; May, M.; Widmann, K.; Glendinning, G.; Castor, J.; Sain, J.; Baker, K.; Hsing, W. W.; Young, B.; and others

    2014-06-15

    Experiments that characterize and develop a high energy-density half-hohlraum platform for use in benchmarking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic diffusive Marshak wave, which propagates into a high atomic number Ta{sub 2}O{sub 5} aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range of x-ray measurements that absolutely quantify the energetics and radiation partition inside the target.

  20. Visualization of transient phenomena during the interaction of pulsed CO2 laser radiation with matter

    NASA Astrophysics Data System (ADS)

    Schmitt, R.; Hugenschmidt, Manfred

    1996-05-01

    Carbon-dioxide-lasers operating in the pulsed mode with energy densities up to several tens of J/cm2 and peak power densities in the multi-MW/cm2-range may cause fast heating and melting. Eventually quasi-explosive ejection, decomposition or vaporization of material can be observed. Surface plasmas are strongly influencing the energy transfer from the laser radiation field to any target. For optically transparent plastics, such as PMMA for example, only slowly expanding plasmas (LSC-waves) are ignited at fluences around 20 J/cm2, with a low level of self-luminosity. High brightness, supersonically expanding plasma jets (LSD-waves) are generated at the same fluences on glasses. Similar conditions were found for metals as well. From recordings with a high speed CCD-camera, interesting features concerning the initial plasma phases and temporal evolution were deduced. Additionally, information was obtained concerning the quasi explosive ejection of material for PMMA.

  1. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2012

    SciTech Connect

    Voyles, JW

    2012-10-10

    Individual datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile research sites are collected and routed to the Data Management Facility (DMF) for processing in near-real-time. Instrument and processed data are then delivered approximately daily to the ARM Data Archive, where they are made freely available to the research community. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Data Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  2. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report October 1–December 31, 2012

    SciTech Connect

    Voyles, JW

    2013-01-11

    Individual datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile research sites are collected and routed to the Data Management Facility (DMF) for processing in near-real-time. Instrument and processed data are then delivered approximately daily to the ARM Data Archive, where they are made freely available to the research community. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Data Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year dating back to 1998.

  3. Structures of heterogeneous systems determined using XFEL pulses in the face of radiation damage

    NASA Astrophysics Data System (ADS)

    Young, Linda; Ho, Phay; Knight, Chris; Bostedt, Christoph; Faigl, Gyula; Tegze, Miklos

    2016-05-01

    Intense, femtosecond x-ray free-electron laser pulses are a promising tool for studying the structure and dynamics of complex systems at atomic resolution. Our previous efforts, using an atomistic quantum/classical model to track the dynamical evolution of ions and electrons throughout a femtosecond x-ray pulse and out to picosecond timescales, focused on quantifying the effects of radiation damage on homogeneous rare gas clusters for imaging applications in an ideal situation. In these studies, the entire 3D Q-space scattering pattern was computed and available for reconstruction of the initial structure. However, a realistic representation of an experiment would feature a collection of noisy 2D scattering patterns, from which orientation would first be required to generate the 3D Q-space distribution from which solution of the phase problem and reconstruction would then proceed. We will present the first results of these efforts on heterogeneous systems. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.

  4. 10 CFR Appendix A to Part 835 - Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE Facilities

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE Facilities A Appendix A to Part 835 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Pt. 835, App. A Appendix A to Part 835—Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at...

  5. Environmental Radiation Dose Reconstruction for U.S. and Russian Weapons Production Facilities: Hanford and Mayak

    SciTech Connect

    Ansbaugh, Lynn R.; Degteva, M. O.; Kozheurov, V. P.; Napier, Bruce A.; Tolstykh, E. I.; Vorobiova, M. I.

    2003-05-01

    Another way to look at Cold War legacies is to examine the major environmental releases that resulted from past operation of Cold War-related facilities for the manufacture of nuclear weapons. Examining these historical releases and the resultant radiation dose to individuals living near these facilities is called environmental dose reconstruction. Dose reconstructions have been performed or are underway at most large Cold War installations in the United States, such as the Hanford facility; several are also underway in other countries, such as at the Mayak facility in Russia. The efforts in the United States are mostly based on historical operating records and current conditions, which are used to estimate environmental releases, transport, and human exposure. The Russian efforts are largely based on environmental measurements and measurements of human subjects; environmental transport modelling, when conducted, is used to organize and validate the measurements. Past operation of Cold War-related facilities for the manufacture of nuclear weapons has resulted in major releases of radionuclides into the environment. Reconstruction of the historical releases and the resultant radiation dose to individuals in the public living near these facilities is called environmental dose reconstruction. Dose reconstructions have been performed or are underway at most large Cold War installations in the United States; several are also underway in other countries. The types of activity performed, the operating histories, and the radionuclide releases vary widely across the different facilities. The U.S. Hanford Site and the Russian Mayak Production Association are used here to illustrate the nature of the assessed problems and the range of approaches developed to solve them.

  6. Proton Irradiation Facility and space radiation monitoring at the Paul Scherrer Institute.

    PubMed

    Hajdas, W; Zehnder, A; Adams, L; Buehler, P; Harboe-Sorensen, R; Daum, M; Nickson, R; Daly, E; Nieminen, P

    2001-01-01

    The Proton Irradiation Facility (PIF) has been designed and constructed, in cooperation between Paul Scherrer Institute (PSI) and European Space Agency (ESA), for terrestrial proton testing of components and materials for spacecraft. Emphasis has been given to generating realistic proton spectra encountered by space-flights at any potential orbit. The facility, designed in a user-friendly manner, can be readily adapted to the individual requirements of experimenters. It is available for general use serving also in testing of radiation monitors and for proton experiments in different scientific disciplines. The Radiation Environment Monitor REM has been developed for measurements of the spacecraft radiation conditions. Two instruments were launched into space, one into a Geo-stationary Transfer Orbit on board of the STRV-1b satellite and one into a Low Earth Orbit on the Russian MIR station. The next generation of monitors (SREMs--Standard REMs) is currently under development in partnership of ESA, PSI and Contraves-Space. They will operate both as minimum intrusive monitors, which provide radiation housekeeping data and alert the spacecraft when the radiation level crosses allowed limits and as small scientific devices measuring particle spectra and fluxes. Future missions as e.g. INTEGRAL, STRV-1c and PROBA will be equipped with new SREMs. PMID:11770526

  7. Radiation sensitivity of quartz crystal oscillators experiment for the Long Duration Exposure Facility (LDEF), part 2

    NASA Technical Reports Server (NTRS)

    Ahearn, J. S.; Venables, J. D.

    1993-01-01

    The stability of high precision quartz crystal oscillators exposed to the radiation environment of NASA's Long Duration Exposure Facility (LDEF) was studied. Comparisons between pre-flight and post-flight frequency drift rates indicate that oscillators made from swept premium Q quartz exhibited a significantly greater post-flight drift rate than before exposure, but that the effect annealed after five months aging at 75 C (the operating temperature). The result that six years worth of radiation damage annealed out in less than six months suggests that if the oscillators had been powered during the LDEF mission, no net change in drift rate beyond their normal baseline value would have occurred.

  8. Simulations of radiatively-driven implosions on the PBFA-Z facility

    SciTech Connect

    Aubrey, J.B.; Bowers, R.L.; Peterson, D.L.

    1997-05-01

    We have performed two-dimensional calculations of the implosions of thin-walled aluminum cylinders driven by a source of radiation. The source is generated by the stagnation of an imploding plasma liner on to a foam target (dynamic hohlraum or flying radiation case) in the PBFA-Z facility at Sandia National Laboratory in Albuquerque, New Mexico. Both Lagrangian and Eulerian codes are used for the simulations of the compression of the shell by the ablatively-driven main shock. {copyright} {ital 1997 American Institute of Physics.}

  9. Generation of thermo-acoustic waves from pulsed solar/IR radiation

    NASA Astrophysics Data System (ADS)

    Rahman, Aowabin

    Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

  10. Survey of high-enthalpy shock facilities in the perspective of radiation and chemical kinetics investigations

    NASA Astrophysics Data System (ADS)

    Reynier, Philippe

    2016-08-01

    This contribution is a survey of the capabilities of the main facilities, shock-tubes, shock-tunnels, expansion tubes and hot-shots that allow the experimental investigation of chemical kinetics and radiation of hypersonic flows encountered during atmospheric entry. At first, the capabilities of the main facilities available in Australia, Asia, Europe, and United States, have been surveyed using the available literature, and the specific use of each facility identified. The second step of the study consists in an analysis of each type of shock facility to identify their advantages and drawbacks. The main objective of this analysis is to support a trade-off for the selection of the type of facility to be developed in order to give Europe a ground test with the capabilities to support future exploration and sample return missions. The last point of the study has been to identify the experimental datasets related to the targeted application, and to select the most attractive for the validation of the future facility.

  11. Passive and Active Radiation Measurements Capability at the INL Zero Power Physics Reactor (ZPPR) Facility

    SciTech Connect

    Robert Neibert; John Zabriskie; Collin Knight; James L. Jones

    2010-12-01

    The Zero Power Physics Reactor (ZPPR) facility is a Department of Energy facility located in the Idaho National Laboratory’s (INL) Materials and Fuels Complex. It contains various nuclear and non-nuclear materials that are available to support many radiation measurement assessments. User-selected, single material, nuclear and non-nuclear materials can be readily utilized with ZPPR clamshell containers with almost no criticality concerns. If custom, multi-material configurations are desired, the ZPPR clamshell or an approved aluminum Inspection Object (IO) Box container may be utilized, yet each specific material configuration will require a criticality assessment. As an example of the specialized material configurations possible, the National Nuclear Security Agency’s Office of Nuclear Verification (NNSA/NA 243) has sponsored the assembly of six material configurations. These are shown in the Appendixes and have been designated for semi-permanent storage that can be available to support various radiation measurement applications.

  12. IKNO, a user facility for coherent terahertz and UV synchrotron radiation

    SciTech Connect

    Sannibale, Fernando; Marcelli, Augusto; Innocenzi, Plinio

    2008-04-26

    IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation (SR) ranging from the IR to the VUV. IKNO can be operated in an ultra-stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing 3rd generation light sources. Simultaneously to the CSR operation, broadband incoherent SR up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent SR are described in this paper. The proposed location for the infrastructure facility is in Sardinia, Italy.

  13. Experimental study of pulsed power driven radiative shockwaves in noble gases

    NASA Astrophysics Data System (ADS)

    Skidmore, J.; Lebedev, S.; Suzuki-Vidal, F.; Bland, S.; Swadling, G.; Burdiak, G.; Hall, G.; Patankar, S.; de Grouchy, P.; Suttle, L.; Bennett, M.; Pickworth, L.; Khoory, E.; Smith, R.; Rodriguez, R.; Gil, J.

    2013-10-01

    The use of plastic disks coated with a thin film of Aluminium has been investigated as a control mechanism for the shockwave formed from a radial foil z-pinch in the presence of an ambient medium. Experiments were carried out on the MAGPIE (1.4 MA, 250 ns rise time) facility at Imperial College London. The configuration produces a strong radiative shockwave driven with constant velocity (>25 km/s) for long time (>400 ns) and spatial scales (cm). Experimental results demonstrate scaling of shock compression opposite to that found in 1D radiation hydrodynamic simulations. Evidence of a thermal instability in the post-shock cooling region is linked to a decrease in compression for higher atomic masses due to increased radiative cooling. Increases in post-shock temperature and ionization have been measured with decreased radial distance from a strongly cooling hydrodynamic jet. Regions of observed thermal instability for Xenon and Krypton agree with those expected from evaluation of theoretical cooling functions. Institute of Shock Physics, Imperial College London.

  14. The Advanced Light Source at Lawrence Berkeley Laboratory: A high-brightness soft x-ray synchrotron-radiation facility

    SciTech Connect

    Schlachter, A.S.; Robinson, A.L.

    1990-07-01

    The Advanced Light Source, a third-generation national synchrotron-radiation facility now under construction at the Lawrence Berkeley Laboratory, is scheduled to begin serving qualified users across a broad spectrum of research areas in the spring of 1993. Based on a low-emittance electron storage ring optimized to operate at 1.5 GeV, the ALS will have 10 long straight sections available for insertion devices (undulators and wigglers) and 24 high-quality bend-magnet ports. The short pulse width (30--50 ns) will be ideal for time-resolved measurements. Undulators will generate high-brightness soft x-ray and ultraviolet (XUV) radiation from below 20 eV to above 2 keV. Wigglers and bend magnets will extend the spectrum by generating high fluxes of hard x-rays to photon energies above 10 keV. The ALS will support an extensive research program in which XUV radiation is used to study matter in all its varied gaseous, liquid, and solid forms. The high brightness will open new areas of research in the materials sciences, such as spatially resolved spectroscopy (spectromicroscopy). Biological applications will include x-ray microscopy with element-specific sensitivity in the water window of the spectrum where water is much more transparent than protein. The ALS will be an excellent research tool for atomic physics and chemistry because the high flux will allow measurements to be made with tenuous gas-phase targets. 8 refs., 7 figs., 3 tabs.

  15. Rationale for a spallation neutron source target system test facility at the 1-MW Long-Pulse Spallation Source

    SciTech Connect

    Sommer, W.F.

    1995-12-01

    The conceptual design study for a 1-MW Long-Pulse Spallation Source at the Los Alamos Neutron Science Center has shown the feasibility of including a spallation neutron test facility at a relatively low cost. This document presents a rationale for developing such a test bed. Currently, neutron scattering facilities operate at a maximum power of 0.2 MW. Proposed new designs call for power levels as high as 10 MW, and future transmutation activities may require as much as 200 MW. A test bed will allow assessment of target neutronics; thermal hydraulics; remote handling; mechanical structure; corrosion in aqueous, non-aqueous, liquid metal, and molten salt systems; thermal shock on systems and system components; and materials for target systems. Reliable data in these areas are crucial to the safe and reliable operation of new high-power facilities. These tests will provide data useful not only to spallation neutron sources proposed or under development, but also to other projects in accelerator-driven transmutation technologies such as the production of tritium.

  16. RADIATION ACCESS ZONE AND VENTILATION CONFINEMENT ZONE CRITERIA FOR THE MGR SURFACE FACILITIES

    SciTech Connect

    D. A. Padula

    2000-09-13

    The objectives of this technical report are to: (1) Establish the criteria for Radiation Access Zone (RAZ) designation. (2) Establish the criteria for the Ventilation Confinement Zone (VCZ) designation. The scope will be to formulate the RAZ and VCZ zoning designation for the Monitored Geologic Repository (MGR) surface facilities and to apply the zoning designations to the current Waste Handling Building (WHB), Waste Treatment Building (WTB), and Carrier Preparation Building (CPB) configurations.

  17. Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

    SciTech Connect

    Oothoudt, M.; Pillai, C.; Zumbro, M.

    1997-08-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances.

  18. Effect of background gas pressure and laser pulse intensity on laser induced plasma radiation of copper samples

    NASA Astrophysics Data System (ADS)

    Mehrabian, S.; Aghaei, M.; Tavassoli, S. H.

    2010-04-01

    Study of laser induced plasma emission of Cu in one dimension is numerically carried out. Effects of different background gas pressure (He), 100, 500, and 760 torr, and laser pulse intensities, 0.5, 0.7, and 1 GW/cm2, on the plasma emission as well as ablation processes are investigated. Under a specified condition, heat conduction equation in the target accompanied with gas dynamic equations in the plume is solved simultaneously. The mentioned equations are coupled to each other through the Knudsen layer conditions and the energy and mass balances at the interface between the target and the vapor. The Bremsstrahlung radiation of plasma and the spectral emission of copper atoms are studied under various background gas pressure and laser pulse intensities. Furthermore, number density of He, Cu, and the electron, pressure, and temperature of the plume under various conditions are obtained. In the early time after laser pulse, plasma radiation is mainly due to the Bremsstrahlung radiation while after some 10 ns, the plasma radiation is dominated by spectral emission of Cu atoms. A similar uncoupling is observed spatially. The Bremsstrahlung emission is dominant near the sample surface while at farther points the spectral emission is the dominant one. By increase in the background pressure and also the pulse intensity, the dominancy of the spectral emission would occur later in time and farther in position.

  19. Influences of different gases on the terahertz radiation based on the application of two-color laser pulses

    SciTech Connect

    Moradi, S.; Ganjovi, A.; Shojaei, F.; Saeed, M.

    2015-10-15

    In this work, using a two-dimensional Particle In Cell-Monte Carlo Collision simulation method, a comparative study is performed on the influences of different types of atomic and molecular gases at various background gas pressures on the generation of broadband and intense Terahertz (THz) radiation via the application of two-color laser pulses. These two modes are focused into Argon (Ar), Xenon (Xe), Nitrogen (N{sub 2}), Oxygen (O{sub 2}), and air as the background gaseous media and the plasma channel is created. It is observed that the THz radiation emission dramatically changes due to the propagation effects. A wider THz pulse is emitted from the formed plasma channel at the higher gas pressures. The significant effects of the propagation features of the emitted THz pulse on its energy at the longer lengths of the plasma channel are observed.

  20. Analysis of Dietz`s single, rectangular pulse theory for the generation of radiation via photoelectrons

    SciTech Connect

    Dipp, T.M.

    1993-12-01

    The generation of radiation via photoelectrons induced off of a conducting surface has been analytically modeled and computationally simulated by several researchers. This paper analyzes and compares Dietz`s theory predictions with my research to form a unified foundation of consistent, inter-supporting results that should provide confidence in the independently performed basic research and resulting scaling laws and predictions. In doing so, this paper concentrated on Dietz`s small-spot, single, rectangular, ``weak`` pulse theory and equations, which involve nonrelativistic, monoenergetic photoelectrons emitted normal to a conducting surface in vacuum. In this paper I: (1) analytically compare Dietz`s theory equations with my theory equations, (2) compare Dietz`s theoretical scaling laws with my Particle-In-Cell (PIC) code simulation results, and (3) make Dietz`s equations easier to use in predicting and optimizing photoelectron-generated radiation. As a result, it is shown that Dietz`s equations match my theory`s equations in their predicted scaling laws, differing only slightly in their coefficients and unique model parameters. Also, Dietz`s equations generally agree with the PIC code results. Finally, optimization analysis showed that theoretical conversion efficiencies for typical real metals can meet and exceed values of 10{sup {minus}5} if optimal photon energies of 15 to 20 eV are used. Even better efficiencies should be possible if the small-spot constraint is violated as well.

  1. An assessment of research opportunities and the need for synchrotron radiation facilities

    SciTech Connect

    1995-12-31

    The workshop focused on six topics, all of which are areas of active research: (1) speciation, reactivity and mobility of contaminants in aqueous systems, (2) the role of surfaces and interfaces in molecular environmental science, (3) the role of solid phases in molecular environmental science, (4) molecular biological processes affecting speciation, reactivity, and mobility of contaminants in the environment, (5) molecular constraints on macroscopic- and field-scale processes, and (6) synchrotron radiation facilities and molecular environmental sciences. These topics span a range of important issues in molecular environmental science. They focus on the basic knowledge required for understanding contaminant transport and fate and for the development of science-based remediation and waste management technologies. Each topic was assigned to a working group charged with discussing recent research accomplishments, significant research opportunities, methods required for obtaining molecular-scale information on environmental contaminants and processes, and the value of synchrotron x-ray methods relative to other methods in providing this information. A special working group on synchrotron radiation facilities was convened to provide technical information about experimental facilities at the four DOE-supported synchrotron radiation sources in the US (NSLS, SSRL, AS and UPS) and synchrotron- based methods available for molecular environmental science research. Similar information on the NSF-funded Cornell High Energy synchrotron Source (CHESS) was obtained after the workshop was held.

  2. Design of an irradiation facility with a real-time radiation effects monitoring capability

    NASA Astrophysics Data System (ADS)

    Braisted, J.; Schneider, E.; O'Kelly, S.; van der Hoeven, C.

    2011-12-01

    An in-core irradiation facility for radiation effects testing with a real-time monitoring capability has been designed for the 1.1 MW TRIGA Mark II research reactor at The University of Texas at Austin. The facility is larger than any currently available non-central location in a TRIGA, supporting testing of larger electronic components as well as other in-core irradiation applications requiring significant volume such as isotope production or neutron transmutation doping of silicon. This article presents the layout and characterization of the large in-core irradiation facility and the real-time electronics performance monitoring capability it is designed to support. To demonstrate this capability, an experimental campaign was conducted where the real-time current transfer ratio for 4N25 general-purpose optocouplers was obtained from in-situ voltage measurements. The resultant radiation effects data - current transfer ratio as a function of neutron and gamma dose - was seen to be repeatable and exceptionally finely resolved. Therefore, the real-time capability at UT TRIGA appears competitive with other effects characterization facilities in terms of number and size of testable samples while additionally offering a novel real-time, in-core monitoring capability.

  3. Terahertz radiation from Cd{sub x}Hg{sub 1-x}Te photoexcited by femtosecond laser pulses

    SciTech Connect

    Krotkus, A.; Adomavicius, R.; Molis, G.; Urbanowicz, A.; Eusebe, H.

    2004-10-01

    Terahertz radiation from Cd{sub x}Hg{sub 1-x}Te samples excited by femtosecond Ti:sapphire laser pulses were measured by using an ultrafast photoconductive antenna manufactured from low-temperature grown GaAs. Terahertz fields radiated by the samples of all three investigated alloy compositions with x=0, 0.2, and 0.3 were of the same order of magnitude. No azimuthal angle dependence of the radiated signal was detected, which evidences that linear current surge effect is dominating over nonlinear optical rectification.

  4. Plasma channel produced by femtosecond laser pulses as a medium for amplifying electromagnetic radiation of the subterahertz frequency range

    SciTech Connect

    Bogatskaya, A V; Volkova, E A; Popov, A M

    2013-12-31

    The electron energy distribution function in the plasma channel produced by a femtosecond laser pulse with a wavelength of 248 nm in atmospheric-pressure gases was considered. Conditions were determined whereby this channel may be employed for amplifying electromagnetic waves up to the terahertz frequency range over the energy spectrum relaxation time ∼10{sup -7} s. Gains were calculated as functions of time and radiation frequency. The effect of electron – electron collisions on the rate of relaxation processes in the plasma and on its ability to amplify the electromagnetic radiation was investigated. (interaction of laser radiation with matter)

  5. Summary of ionizing radiation analysis on the Long Duration Exposure Facility

    NASA Technical Reports Server (NTRS)

    Parnell, T. A.

    1992-01-01

    The ionizing radiation measurements flown on the Long Duration Exposure Facility (LDEF) were contained in 15 experiments which utilized passive detectors to pursue objectives in astrophysics and to measure the radiation environment and dosimetric quantities. The spacecraft structure became sufficiently radioactive to permit additional important studies. The induced activity allows extensive radiation mapping in the structure, and independent comparison with experiment dosimetric techniques, and significant studies of secondary effects. The long exposure time, attitude stability, and number and types of measurements produced a unique and critical set of data for low Earth orbit that will not be duplicated for more than a decade. The data allow an unprecedented test, and improvement if required, of models of the radiation environment and the radiation transport methods that are used to calculate the internal radiation and its effects in spacecraft. Results of measurements in the experiments, as well as from radioactivity in the structure, have clearly shown effects from the directional properties of the radiation environment, and progress was made in the dosimetric mapping of LDEF. These measurements have already influenced some Space Station Freedom design requirements. Preliminary results from experiments, reported at this symposium and in earlier papers, show that the 5.8 years exposure considerably enhanced the scientific return of the radiation measurements. The early results give confidence that the experiments will make significant advances in the knowledge of ultra heavy cosmic rays, anomalous cosmic rays, and heavy ions trapped in the radiation belts. Unexpected phenomena were observed, which require explanation. These include stopping iron group ions between the energy ranges anticipated for anomalous and galactic cosmic rays in the LDEF orbit. A surprising concentration of the Be-7 nuclide was discovered on the 'front' surface of LDEF, apparently

  6. Non-Evaporable Getter Coatings at the European Synchrotron Radiation Facility

    NASA Astrophysics Data System (ADS)

    Hahn, Michael

    A large majority of insertion device (ID) vacuum sectors on the European Synchrotron Radiation Facility (ESRF) electron storage ring for the production of intense synchrotron radiation are equipped with flat vacuum vessels made of extruded aluminum using a non-evaporable Getter (NEG) coating to reduce the vacuum pressure bump along the chamber during the operation of the accelerator. After the in-situ activation of the sputtered film by bake-out of the vacuum system the NEG pumps gases such as H2, CO and CO2 while CH4 and noble gases are not pumped. Because a low activation temperature for the NEG is necessary to be compatible with the mechanical limitations of the aluminum alloy, the NEG composition of TiZrV has been chosen. During operation of the ESRF electron storage ring a few hundreds of watts of synchrotron radiation fall on the walls of the ID chambers leading to photodesorption and photo-conditioning. The NEG coating is intended to provide distributed pumping and reduced photodesorption to keep the generation of unwanted Bremsstrahlung radiation following the installation of a new vessel low. The deposit of the NEG coating takes place at a dedicated facility in the ESRF.

  7. Installation of a Synchrotron Radiation Beamline Facility at the J. Bennett Johnston Center. Final Report

    SciTech Connect

    Gooden, R.

    2000-03-21

    The Johnston Center presents a unique opportunity for scientists and engineers at southern institutions to initiate and carry out original research using synchrotron radiation ranging from visible light to hard x-rays. The Science and Engineering Alliance proposes to carry out a comprehensive new synchrotron radiation research initiative at CAMD in carefully phased steps of increasing risks. (1) materials research on existing CAMD beam lines and end stations; (2) design, construction and installation of end stations on existing CAMD beam lines, and research with this new instrumentation; (3) design, construction and operation of dedicated synchrotron radiation beam lines that covers the full spectral range of the CAMD storage ring and expanded research in the new facility.

  8. Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

    SciTech Connect

    Moore, A. S.; Cooper, A. B.R.; Schneider, M. B.; MacLaren, S.; Graham, P.; Lu, K.; Seugling, R.; Satcher, J.; Klingmann, J.; Comley, A. J.; Marrs, R.; May, M.; Widmann, K.; Glendinning, G.; Castor, J.; Sain, J.; Back, C. A.; Hund, J.; Baker, K.; Hsing, W. W.; Foster, J.; Young, B.; Young, P.

    2014-06-01

    Experiments that characterize and develop a high energy-density half-hohlraum platform for use in bench-marking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic di usive Marshak wave which propagates into a high atomic number Ta2O5 aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range

  9. Knowledge, skills, and abilities for key radiation protection positions at DOE facilities

    SciTech Connect

    1997-01-01

    This document provides detailed qualification criteria for contractor key radiation protection personnel. Although federal key radiation protection positions are also identified, qualification standards for federal positions are provided in DOE O 360.1 and the DOE Technical Qualifications Program. Appendices B and D provide detailed listings for knowledge, skills, and abilities for contractor and DOE federal key radiation protection positions. This information may be used in developing position descriptions and individual development plans. Information provided in Appendix C may be useful in developing performance measures and assessing an individual`s performance in his or her specific position. Additionally, Federal personnel may use this information to augment their Office/facility qualification standards under the Technical Qualifications Program.

  10. Single-pulse driven, large-aperture 2×1 array plasma-electrodes optical switch for SG-II upgrading facility

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Wu, Dengsheng; Zheng, Jiangang; Zheng, Kuixing; Zhu, Qihua; Zhang, Xiongjun

    2014-12-01

    We demonstrate the design and performance of an optical switch that has been constructed for the SG-II upgrading facility. The device is a longitudinal, potassium di-hydrogen phosphate (KDP), 360 mm×360 mm aperture, and 2×1 array electro-optical switch driven by a 20 kV output switching-voltage pulse generator through two plasma electrodes produced at the rise edge of the switching-voltage pulse. The results show that the temporal responses and the spatial performance of the optical switch fulfill the operation requirements of the SG-II upgrading facility.

  11. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling

    PubMed Central

    Lumbreras, Vicente; Bas, Esperanza; Gupta, Chhavi

    2014-01-01

    Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca2+ imaging. Both types of neurons responded consistently with robust intracellular Ca2+ ([Ca2+]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25–1 pps). Radiant exposures of ∼637 mJ/cm2 resulted in continual neuronal activation. Temperature or [Ca2+] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca2+ involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na+, K+, and Ca2+ plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca2+ cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca2+]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca2+ release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses. PMID:24920028

  12. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers.

    PubMed

    Zajnulina, M; Böhm, M; Blow, K; Rieznik, A A; Giannone, D; Haynes, R; Roth, M M

    2015-10-01

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs. PMID:26520070

  13. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

    SciTech Connect

    Zajnulina, M.; Giannone, D.; Haynes, R.; Roth, M. M.; Böhm, M.; Blow, K.; Rieznik, A. A.

    2015-10-15

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs.

  14. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling.

    PubMed

    Lumbreras, Vicente; Bas, Esperanza; Gupta, Chhavi; Rajguru, Suhrud M

    2014-09-15

    Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses. PMID:24920028

  15. A comparative study of the bactericidal activity and daily disinfection housekeeping surfaces by a new portable pulsed UV radiation device.

    PubMed

    Umezawa, Kazuo; Asai, Satomi; Inokuchi, Sadaki; Miyachi, Hayato

    2012-06-01

    Daily cleaning and disinfecting of non-critical surfaces in the patient-care areas are known to reduce the occurrence of health care-associated infections. However, the conventional means for decontamination of housekeeping surfaces of sites of frequent hand contact such as manual disinfection using ethanol wipes are laborious and time-consuming in daily practice. This study evaluated a newly developed portable pulsed ultraviolet (UV) radiation device for its bactericidal activity in comparison with continuous UV-C, and investigated its effect on the labor burden when implemented in a hospital ward. Pseudomonas aeruginosa, Multidrug-resistant P. aeruginosa, Escherichia coli, Acinetobacter baumannii, Amikacin and Ciprofloxacin-resistant A. baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus cereus were irradiated with pulsed UV or continuous UV-C. Pulsed UV and continuous UV-C required 5 and 30 s of irradiation, respectively, to attain bactericidal activity with more than 2Log growth inhibition of all the species. The use of pulsed UV in daily disinfection of housekeeping surfaces reduced the working hours by half in comparison to manual disinfection using ethanol wipes. The new portable pulsed UV radiation device was proven to have a bactericidal activity against critical nosocomial bacteria, including antimicrobial-resistant bacteria after short irradiation, and was thus found to be practical as a method for disinfecting housekeeping surfaces and decreasing the labor burden. PMID:22447288

  16. An Investigation into the Effect of High-Power Pulse IR Radiation on the Properties of Surfaces of CdxHg1-хTe Heteroepitaxial Layers

    NASA Astrophysics Data System (ADS)

    Boltar', K. O.; Burlakov, I. D.; Voitsekhovskii, А. V.; Sizov, А. L.; Sredin, V. G.; Talipov, N. Kh.; Shul'ga, S. А.

    2013-12-01

    The results of investigations into radiation modification of surfaces of Cd x Hg1- x Te (CMT) heteroepitaxial layers grown by molecular-beam and liquid-phase epitaxy (MBE- and LPE CMT HEL) affected by high-power pulse short-wavelength IR radiation are discussed. It is found that the surfaces of MBE CMT HEL and LPE CMT are enhanced by mercury as a result of high-power pulse short-wavelength IR radiation.

  17. Generation of surface waves and low-frequency radiation under exposure of a conductor to a laser pulse focused by a cylindrical lens

    SciTech Connect

    Uryupin, S A; Frolov, A A

    2014-09-30

    We have developed a theory of generation of low-frequency radiation and surface waves under the pondermotive action of a femtosecond laser pulse irradiating a conductor along the normal and focused by a cylindrical lens. It is shown that for the chosen focusing method and specified values of laser pulse duration and flux density it is possible to significantly increase the total energy of both surface waves and low-frequency radiation. (terahertz radiation)

  18. The radiation temperature and M-band fraction inside hohlraum on the SGIII-prototype laser facility

    SciTech Connect

    Yi Huo, Wen; Lan, Ke; Li, Yongsheng; Li, Xin; Wu, Changshu; Ren, Guoli; Zhao, Yiqing; Zou, Shiyang; Zheng, Wudi; Gu, Peijun; Wang, Min; Yang, Dong; Li, Sanwei; Yi, Rongqing; Jiang, Xiaohua; Song, Tianming; Li, Zhichao; Guo, Liang; Liu, Yonggang; Zhan, Xiayu; and others

    2014-02-15

    The radiation temperature T{sub R} and M-band fraction f{sub M} inside the vacuum Au hohlraum have been experimentally determined by a shock wave technique and a broadband soft x-ray spectrometer (SXS) on the SGIII-prototype laser facility. From the results of the shock wave technique, T{sub R} is about 202 eV, and f{sub M} is about 9% for the hohlraums driven by a 1 ns flattop pulse of 6 kJ laser energy. The Continuous Phase Plate (CPP) for beam smoothing is applied in the experiment, which increases T{sub R} to 207 eV while has almost no influence on f{sub M}. Comparisons between the results from the two kinds of technologies show that T{sub R} from the shock wave technique is lower than that from SXS whether with CPP or not. However, f{sub M} from the shock wave technique is consistent with that from SXS without CPP, but obviously lower than the SXS's result with CPP. The preheat effect on exterior surface of witness plate is reduced by thicker thickness of witness plate designed for higher laser driven energy.

  19. The radiation temperature and M-band fraction inside hohlraum on the SGIII-prototype laser facility

    NASA Astrophysics Data System (ADS)

    Yi Huo, Wen; Yang, Dong; Lan, Ke; Li, Sanwei; Li, Yongsheng; Li, Xin; Wu, Changshu; Ren, Guoli; Zhao, Yiqing; Zou, Shiyang; Zheng, Wudi; Gu, Peijun; Wang, Min; Yi, Rongqing; Jiang, Xiaohua; Song, Tianming; Li, Zhichao; Guo, Liang; Liu, Yonggang; Zhan, Xiayu; Wang, Feng; Peng, Xiaoshi; Zhang, Huan; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Ding, Yongkun

    2014-02-01

    The radiation temperature TR and M-band fraction fM inside the vacuum Au hohlraum have been experimentally determined by a shock wave technique and a broadband soft x-ray spectrometer (SXS) on the SGIII-prototype laser facility. From the results of the shock wave technique, TR is about 202 eV, and fM is about 9% for the hohlraums driven by a 1 ns flattop pulse of 6 kJ laser energy. The Continuous Phase Plate (CPP) for beam smoothing is applied in the experiment, which increases TR to 207 eV while has almost no influence on fM. Comparisons between the results from the two kinds of technologies show that TR from the shock wave technique is lower than that from SXS whether with CPP or not. However, fM from the shock wave technique is consistent with that from SXS without CPP, but obviously lower than the SXS's result with CPP. The preheat effect on exterior surface of witness plate is reduced by thicker thickness of witness plate designed for higher laser driven energy.

  20. A pulse-forming network for particle path visualization. [at Ames Aeromechanics Water Tunnel Facility

    NASA Technical Reports Server (NTRS)

    Mcalister, K. W.

    1981-01-01

    A procedure is described for visualizing nonsteady fluid flow patterns over a wide velocity range using discrete nonluminous particles. The paramount element responsible for this capability is a pulse-forming network with variable inductance that is used to modulate the discharge of a fixed amount of electrical energy through a xenon flashtube. The selectable duration of the resultant light emission functions as a variable shutter so that particle path images of constant length can be recorded. The particles employed as flow markers are hydrogen bubbles that are generated by electrolysis in a water tunnel. Data are presented which document the characteristics of the electrical circuit and establish the relation of particle velocity to both section inductance and film exposure.

  1. Picosecond pulses of coherent MM-wave radiation in a photoinjector-driven waveguide free-selected laser

    SciTech Connect

    Fochs, S.N.; Le Sage, G.P.; Feng, L.

    1995-12-31

    A 5 MeV, high repetition rate (2.142 GHz in burst mode), high brightness, tabletop photoinjector is currently under construction at the UC Davis Department of Applied Science, on the LLNL site. Ultrashort pulses of coherent synchrotron radiation can be generated by transversally accelerating the electron beam with a wiggler in either metallic or dielectric-loaded waveguide FEL structures. This interaction is investigated theoretically and experimentally. Subpicosecond photoelectron bunches will be produced in the photoinjector by irradiating a high quantum efficiency Cs{sub 2}Te (Cesium Telluride) photocathode with a train of 100 UV (210 nm), ultra-short (250 fs) laser pulses. These bunches will be accelerated in a 1-1/2 cell {pi}-mode X-band RF gun e energized by a 20 MW, 8,568 GHz SLAC klystron. The peak current is 0.25 kA (0.25 nC, 1 ps), with a normalized beam emittance {epsilon}{sub n}<2.5 {pi} mm-mrad. This prebunched electron beam is then transversally accelerated in a cylindrical waveguide by a 30-mm period, 10 period long helical wiggler. The peak wiggler field is adjusted to 8.5 kG, so that the group velocity of the radiated electromagnetic waves matches the axial velocity of the electron bunch (grazing condition, zero slippage). Chirped output pulses in excess of 2 MW power are predicted, with an instantaneous bandwidth extending from 125 GHz to 225 GHz and a pulse duration of 15 ps (HWHM). To produce even shorter pulses, a dielectric-loaded waveguide can be used. The dispersion relation of this waveguide structure has an inflection point (zero group velocity dispersion). If the grazing condition is satisfied at this point, the final output pulse duration is no longer determined by slippage, or by group velocity dispersion and bandwidth, but by higher-order dispersive effects yielding transform-limited pulses.

  2. Numerical and experimental studies of mechanisms underlying the effect of pulsed broadband terahertz radiation on nerve cells

    SciTech Connect

    Duka, M V; Dvoretskaya, L N; Babelkin, N S; Khodzitskii, M K; Chivilikhin, S A; Smolyanskaya, O A

    2014-08-31

    We have studied the mechanisms underlying the effect of pulsed broadband terahertz radiation on the growth of neurites of sensory ganglia using a comparative analysis of measured reflection spectra of ganglion neurites (in the frequency range 0.1 – 2.0 THz) and spectra obtained by numerical simulation with CST Microwave Studio. The observed changes are shown to be mainly due to pulse energy absorption in the ganglion neurites. Of particular interest are the observed single resonance frequencies related to resonance size effects, which can be used to irradiate ganglia in order to activate their growth. (laser biophotonics)

  3. Numerical and experimental studies of mechanisms underlying the effect of pulsed broadband terahertz radiation on nerve cells

    NASA Astrophysics Data System (ADS)

    Duka, M. V.; Dvoretskaya, L. N.; Babelkin, N. S.; Khodzitskii, M. K.; Chivilikhin, S. A.; Smolyanskaya, O. A.

    2014-08-01

    We have studied the mechanisms underlying the effect of pulsed broadband terahertz radiation on the growth of neurites of sensory ganglia using a comparative analysis of measured reflection spectra of ganglion neurites (in the frequency range 0.1 - 2.0 THz) and spectra obtained by numerical simulation with CST Microwave Studio. The observed changes are shown to be mainly due to pulse energy absorption in the ganglion neurites. Of particular interest are the observed single resonance frequencies related to resonance size effects, which can be used to irradiate ganglia in order to activate their growth.

  4. Numerical and simulation study of terahertz radiation generation by laser pulses propagating in the extraordinary mode in magnetized plasma

    SciTech Connect

    Jha, Pallavi; Kumar Verma, Nirmal

    2014-06-15

    A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.

  5. High-Precision Time Delay Control with Continuous Phase Shifter for Pump-Probe Experiments Using Synchrotron Radiation Pulses

    SciTech Connect

    Tanaka, Yoshihito; Ohshima, Takashi; Moritomo, Yutaka; Tanaka, Hitoshi; Takata, Masaki

    2010-06-23

    Brilliant pulsed x-ray synchrotron radiation (SR) is useful for pump-probe experiment such as time-resolved x-ray diffraction, x-ray absorption fine structure, and x-ray spectroscopy. For laser pump-SR x-ray probe experiments, short pulsed lasers are generally synchronized to the SR master oscillator controlling the voltage for acceleration of electron bunches in an accelerator, and the interval between the laser and the SR pulses is changed around the time scale of target phenomenon. Ideal delay control produces any time delay as keeping the time-precision and pointing-stability of optical pulses at a sample position. We constructed the time delay control module using a continuous phase shifter of radio frequency signal and a frequency divider, which can produce the delayed trigger pulses to the laser without degradation of the time precision and the pointing stability. A picoseconds time-resolved x-ray diffraction experiment was demonstrated at SPring-8 storage ring for fast lattice response by femtosecond pulsed laser irradiation, and suggested the possibility of accurate sound velocity measurement. A delay control unit operating with subpicosecond precision has also been designed for femtosecond pump-probe experiments using a free electron laser at SPring-8 campus.

  6. Wakefield issue and its impact on X-ray photon pulse in the SXFEL test facility

    NASA Astrophysics Data System (ADS)

    Song, Minghao; Li, Kai; Feng, Chao; Deng, Haixiao; Liu, Bo; Wang, Dong

    2016-06-01

    Besides the designed beam acceleration, the energy of electrons is changed by the longitudinal wakefields in a real free-electron laser (FEL) facility, which may degrade FEL performances from the theoretical expectation. In this paper, with the help of simulation codes, the wakefields induced beam energy loss in the sophisticated undulator section is calculated for Shanghai soft X-ray FEL, which is a two-stage seeded FEL test facility. While the 1st stage 44 nm FEL output is almost not affected by the wakefields, it is found that a beam energy loss about 0.8 MeV degrades the peak brightness of the 2nd stage 8.8 nm FEL by a factor of 1.6, which however can be compensated by a magnetic field fine tuning of each undulator segment. And the longitudinal coherence of the 8.8 nm FEL output illustrates a slight degradation, because of the beam energy curvatures induced by the wakefields.

  7. Optimization of the dynamic wavefront control of a pulsed kilojoule/nanosecond-petawatt laser facility.

    PubMed

    Zou, Ji-Ping; Sautivet, Anne-Marie; Fils, Jérôme; Martin, Luc; Abdeli, Kahina; Sauteret, Christian; Wattellier, Benoit

    2008-02-10

    The wavefront aberrations in a large-scale, flash-lamp-pumped, high-energy, high-power glass laser system can degrade considerably the quality of the final focal spot, and limit severely the repetition rate. The various aberrations induced on the Laboratoire pour l'Utilisation des Lasers Intenses (LULI), laser facility (LULI2000) throughout the amplification are identified and analyzed in detail. Based on these analyses, an optimized procedure for dynamic wavefront control is then designed and implemented. The lower-order Zernike aberrations can be effectively reduced by combining an adaptive-optics setup, comprising a bimorph deformable mirror and a four-wave lateral shearing interferometer, with a precise alignment system. This enables the laser chain to produce a reproducible focal spot close to the diffraction limit (Strehl ratio approximately 0.7). This allows also to increase the repetition rate, initially limited by the recovery time of the laser amplifiers, by a factor of 2 (one shot per hour). The proposed procedure provides an attractive alternative for dynamic correction of the wavefront aberrations of a laser facility as complex as the LULI2000. PMID:18268782

  8. Optimization of the dynamic wavefront control of a pulsed kilojoule/nanosecond-petawatt laser facility

    NASA Astrophysics Data System (ADS)

    Zou, Ji-Ping; Sautivet, Anne-Marie; Fils, Jérôme; Martin, Luc; Abdeli, Kahina; Sauteret, Christian; Wattellier, Benoit

    2008-02-01

    The wavefront aberrations in a large-scale, flash-lamp-pumped, high-energy, high-power glass laser system can degrade considerably the quality of the final focal spot, and limit severely the repetition rate. The various aberrations induced on the Laboratoire pour l'Utilisation des Lasers Intenses (LULI), laser facility (LULI2000) throughout the amplification are identified and analyzed in detail. Based on these analyses, an optimized procedure for dynamic wavefront control is then designed and implemented. The lower-order Zernike aberrations can be effectively reduced by combining an adaptive-optics setup, comprising a bimorph deformable mirror and a four-wave lateral shearing interferometer, with a precise alignment system. This enables the laser chain to produce a reproducible focal spot close to the diffraction limit (Strehl ratio ~0.7). This allows also to increase the repetition rate, initially limited by the recovery time of the laser amplifiers, by a factor of 2 (one shot per hour). The proposed procedure provides an attractive alternative for dynamic correction of the wavefront aberrations of a laser facility as complex as the LULI2000.

  9. Modeling and Simulation of Radiative Compressible Flows in Aerodynamic Heating Arc-Jet Facility

    NASA Technical Reports Server (NTRS)

    Bensassi, Khalil; Laguna, Alejandro A.; Lani, Andrea; Mansour, Nagi N.

    2016-01-01

    Numerical simulations of an arc heated flow inside NASA's 20 [MW] Aerodynamics heating facility (AHF) are performed in order to investigate the three-dimensional swirling flow and the current distribution inside the wind tunnel. The plasma is considered in Local Thermodynamics Equilibrium(LTE) and is composed of Air-Argon gas mixture. The governing equations are the Navier-Stokes equations that include source terms corresponding to Joule heating and radiative cooling. The former is obtained by solving an electric potential equation, while the latter is calculated using an innovative massively parallel ray-tracing algorithm. The fully coupled system is closed by the thermodynamics relations and transport properties which are obtained from Chapman-Enskog method. A novel strategy was developed in order to enable the flow solver and the radiation calculation to be preformed independently and simultaneously using a different number of processors. Drastic reduction in the computational cost was achieved using this strategy. Details on the numerical methods used for space discretization, time integration and ray-tracing algorithm will be presented. The effect of the radiative cooling on the dynamics of the flow will be investigated. The complete set of equations were implemented within the COOLFluiD Framework. Fig. 1 shows the geometry of the Anode and part of the constrictor of the Aerodynamics heating facility (AHF). Fig. 2 shows the velocity field distribution along (x-y) plane and the streamline in (z-y) plane.

  10. Radiation shielding and patient organ dose study for an accelerator- based BNCT Facility at LBNL

    SciTech Connect

    Costes, S.V.; Vujic, J.; Donahue, R.J.

    1996-10-24

    This study considers the radiation safety aspects of several designs discussed in a previous report of an accelerator-based source of neutrons, based on the [sup 7]Li(p,n) reaction, for a Boron Neutron Capture Therapy (BNCT) Facility at Lawrence Berkeley National Laboratory (LBNL). determines the optimal radiation shield thicknesses for the patient treatment room. Since this is an experimental facility no moderator or reflector is considered in the bulk wall shield design. This will allow the flexibility of using any postulated moderator/reflector design and assumes sufficient shielding even in the absence of a moderator/reflector. In addition the accelerator is assumed to be capable of producing 100 mA of 2.5 MeV proton beam current. The addition of 1% and 2% [sup 10]B (by weight) to the concrete is also investigated. The second part of this paper determines the radiation dose to the major organs of a patient during a treatment. Simulations use the MIRD 5 anthropomorphic phantom to calculate organ doses from a 20 mA proton beam assuming various envisioned moderator/reflector in place. Doses are tabulated by component and for a given uniform [sup 10]B loading in all organs. These are presented in for a BeO moderator and for an Al/AlF[sub 3] moderator. Dose estimates for different [sup 10]B loadings may be scaled.

  11. CIRCULATING ANTIBODY RESPONSE OF MICE EXPOSED TO 9-GHZ PULSED MICROWAVE RADIATION

    EPA Science Inventory

    Female CD-1 mice immunized against the bacterium Streptococcus pneumoniae type III were exposed to 9-GHz pulsed microwaves (pulse repetition rate 970-1.000, pulse width 1.0 micro seconds, peak power 1 W/cm2) at an average incident power density of 1 mW/sq.cm. (calculated SAR = 0....

  12. Key conditions for stable ion radiation pressure acceleration by circularly polarized laser pulses

    NASA Astrophysics Data System (ADS)

    Qiao, B.; Zepf, M.; Gibbon, P.; Borghesi, M.; Schreiber, J.; Geissler, M.

    2011-05-01

    Radiation pressure acceleration (RPA) theoretically may have great potential to revolutionize the study of laserdriven ion accelerators due to its high conversion efficiency and ability to produce high-quality monoenergetic ion beams. However, the instability issue of ion acceleration has been appeared to be a fundamental limitation of the RPA scheme. To solve this issue is very important to the experimental realization and exploitation of this new scheme. In our recent work, we have identified the key condition for efficient and stable ion RPA from thin foils by CP laser pulses, in particular, at currently available moderate laser intensities. That is, the ion beam should remain accompanied with enough co-moving electrons to preserve a local "bunching" electrostatic field during the acceleration. In the realistic LS RPA, the decompression of the co-moving electron layer leads to a change of local electrostatic field from a "bunching" to a "debunching" profile, resulting in premature termination of acceleration. One possible scheme to achieve stable RPA is using a multi-species foil. Two-dimensional PIC simulations show that 100 MeV/u monoenergetic C6+ and/or proton beams are produced by irradiation of a contaminated copper foil with CP lasers at intensities 5 × 1020W/cm2, achievable by current day lasers.

  13. Cylindrically converging radiative shocks in noble gases driven by the MAGPIE pulsed-power device

    NASA Astrophysics Data System (ADS)

    Burdiak, Guy; Lebedev, S.; Harvey-Thompson, Adam; Swadling, G.; Suzuki-Vidal, F.; Skidmore, J.; Suttle, L.; Bennet, M.; Hall, G.; Pickworth, L.; de Grouchy, P.; Bland, S.; Niasse, N.; Rodriguez, R.; Gil, J.; Espinosa, G.

    2013-10-01

    Experimental data from gas-filled cylindrical liner z-pinch experiments are presented. The current discharge from the MAGPIE pulsed-power device at Imperial College London (1.4 MA,240 ns) is applied to a thin walled (80 μm) Al tube with a static gas-fill inside (initial gas density 10-5 g/cc). The system is used to drive cylindrically converging strong shock waves (Us = 20 km/s) into different gases. Axial diagnostics include interferometry, optical streak photography and time gated, spatially resolved optical spectroscopy. The experimental geometry is nominally uniform along the diagnostic line of sight and in addition the shock waves show a high degree of azimuthal symmetry. This allows determination of the radial dependence of axially averaged plasma parameters (ne,Te) . The spectroscopy diagnostic is used to determine the temperature profile across the shock (in the precursor and post-shock regions) in different noble gases. Comparisons are made between experimental temperature and electron density profiles and the 1D radiation-MHD code HELIOS-CR. In addition, varying degrees of shock stability are seen in different noble gases. These observations will be briefly compared to cooling function calculations and analytical stability models.

  14. VISAR blanking due to preheating in a 2-pulses planar experiment at LULI facility

    NASA Astrophysics Data System (ADS)

    Videau, Laurent; Laffite, Stephane; Baton, Sophie; Combis, Patrick; Clerouin, Jean; Koenig, Michel; Recoules, Vanina; Rousseaux, Christophe

    2014-10-01

    Optical diagnostics, such as VISAR (Velocity Interferometer System for Any Reflector), have become essential in shock timing experiments. Their high precisions allow an accurate measurement of shock velocities and chronometry. But, measurements can be compromised by x-ray preheating. In planar shock coalescence experiments recently performed at the LULI facility, VISAR signal loss was observed. In these experiments, a strong shock, launched by a high-intensity spike, catches up with a first one, initially launched by a low-intensity beam. VISAR signal disparition is due to x-ray generated by spike absorption in corona. It does not occur if high-intensity spike starts after VISAR probe beam begins to reflect off the first shock. Based on optical index assessment in quartz, VISAR diagnostic is modelized and compares favorably to experimental results. This provides evidence of the impact of x-ray preheating on VISAR absorption in quartz.

  15. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2006

    SciTech Connect

    DL Sisterson

    2006-10-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998.

  16. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 – June 30, 2006

    SciTech Connect

    DL Sisterson

    2006-07-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year; and (2) site and fiscal year dating back to 1998.

  17. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report October 1–December 31, 2011

    SciTech Connect

    Voyles, JW

    2012-01-09

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  18. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2009

    SciTech Connect

    DL Sisterson

    2009-10-15

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data then are sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by 1) individual data stream, site, and month for the current year and 2) site and fiscal year (FY) dating back to 1998.

  19. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - July 1 - September 30, 2008

    SciTech Connect

    DL Sisterson

    2008-09-30

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  20. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2008

    SciTech Connect

    DL Sisterson

    2008-06-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  1. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2007

    SciTech Connect

    DL Sisterson

    2007-07-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  2. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - October 1 - December 31, 2008

    SciTech Connect

    Sisterson, DL

    2009-01-15

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  3. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 – March 31, 2007

    SciTech Connect

    DL Sisterson

    2007-04-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  4. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - January 1 - March 31, 2008

    SciTech Connect

    Sisterson, DL

    2008-04-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  5. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report: October 1 - December 31, 2010

    SciTech Connect

    Sisterson, DL

    2011-03-02

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  6. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2007

    SciTech Connect

    DL Sisterson

    2008-01-08

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  7. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2009

    SciTech Connect

    DL Sisterson

    2009-03-17

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  8. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 - September 30, 2007

    SciTech Connect

    DL Sisterson

    2007-10-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  9. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2011

    SciTech Connect

    Voyles, JW

    2011-10-10

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  10. Concentrating Photovoltaic Module Testing at NREL's Concentrating Solar Radiation Users Facility

    SciTech Connect

    Bingham, C.; Lewandowski, A.; Stone, K.; Sherif, R.; Ortabasi, U.; Kusek, S.

    2003-05-01

    There has been much recent interest in photovoltaic modules designed to operate with concentrated sunlight (>100 suns). Concentrating photovoltaic (CPV) technology offers an exciting new opportunity as a viable alternative to dish Stirling engines. Advantages of CPV include potential for>40% cell efficiency in the long term (25% now), no moving parts, no intervening heat transfer surface, near-ambient temperature operation, no thermal mass, fast response, concentration reduces cost of cells relative to optics, and scalable to a range of sizes. Over the last few years, we have conducted testing of several CPV modules for DOEs Concentrating Solar Power (CSP) program. The testing facilities are located at the Concentrating Solar Radiation Users Facility (CRULF) and consist the 10 kW High-Flux Solar Furnace (HFSF) and a 14m2 Concentrating Technologies, LLC (CTEK) dish. This paper will primarily describe the test capabilities; module test results will be detailed in the presentation.

  11. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report January 1–March 31, 2012

    SciTech Connect

    Voyles, JW

    2012-04-13

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Data Archive, where they are made available to the research community. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  12. PLANNING TOOLS FOR ESTIMATING RADIATION EXPOSURE AT THE NATIONAL IGNITION FACILITY

    SciTech Connect

    Verbeke, J; Young, M; Brereton, S; Dauffy, L; Hall, J; Hansen, L; Khater, H; Kim, S; Pohl, B; Sitaraman, S

    2010-10-22

    A set of computational tools was developed to help estimate and minimize potential radiation exposure to workers from material activation in the National Ignition Facility (NIF). AAMI (Automated ALARA-MCNP Interface) provides an efficient, automated mechanism to perform the series of calculations required to create dose rate maps for the entire facility with minimal manual user input. NEET (NIF Exposure Estimation Tool) is a web application that combines the information computed by AAMI with a given shot schedule to compute and display the dose rate maps as a function of time. AAMI and NEET are currently used as work planning tools to determine stay-out times for workers following a given shot or set of shots, and to help in estimating integrated doses associated with performing various maintenance activities inside the target bay. Dose rate maps of the target bay were generated following a low-yield 10{sup 16} D-T shot and will be presented in this paper.

  13. Efficient Cherenkov emission of broadband terahertz radiation from an ultrashort laser pulse in a sandwich structure with nonlinear core

    SciTech Connect

    Bodrov, S. B.; Bakunov, M. I.; Hangyo, M.

    2008-11-01

    A scheme for efficient generation of broadband terahertz radiation by a femtosecond laser pulse propagating in a planar sandwichlike structure is proposed. The structure consists of a thin nonlinear core cladded with prisms made of a material with low terahertz absorption. The focused into a line laser pulse propagates in the core as a leaky or waveguide mode and emits Cherenkov wedge of terahertz waves in the cladding. We developed a theory that describes terahertz generation in such a structure and calculated spatial distribution of the generated terahertz field, its energy spectrum and optical-to-terahertz conversion efficiency. The developed theory predicts the conversion efficiency of up to several percent in a 1 cm long and 1 cm wide Si-LiNbO{sub 3}-Si sandwich structure with a 20 {mu}m thick nonlinear layer pumped by 8.5 {mu}J Ti:sapphire laser with pulse duration of 100 fs.

  14. Interaction of soft x-ray laser pulse radiation with aluminum surface: Nano-meter size surface modification

    SciTech Connect

    Ishino, Masahiko; Faenov, Anatoly; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi; Pikuz, Tatiana; Inogamov, Nail; Zhakhovsky, Vasily; Skobelev, Igor; Fortov, Vladimir; Khohlov, Viktor; Shepelev, Vadim; Ohba, Toshiyuki; Kaihori, Takeshi; Ochi, Yoshihiro; Imazono, Takashi; Kawachi, Tetsuya

    2012-07-11

    Interaction of soft x-ray laser radiation with material and caused modification of the exposed surface has both physical and practical interests. We irradiated the focusing soft x-ray laser (SXRL) pulses having a wavelength of 13.9 nm and the duration of 7 ps to aluminum (Al) surface. After the SXRL irradiation process, the irradiated Al surface was observed with a scanning electron microscope. The surface modifications caused by SXRL single pulse exposure were clearly seen. In addition, it was found that the conical structures having around 100 nm in diameters were formed in the shallow features. The nano-meter size modified structures at Al surface induced by SXRL pulse is interesting as the newly surface structure. Hence, the SXRL beam would be a candidate for a tool of micromachining. We also provide a thermomechanical modeling of SXRL interaction with Al briefly to explain the surface modification.

  15. Calibrating the light pulse shape of a hydrogen flashlamp using synchrotron radiation as a standard of excitation.

    PubMed

    Andre, J C; Lopez-Delgado, R; Lyke, R L; Ware, W R

    1979-05-01

    Advantage has been taken of the measured pulse width of synchrotron radiation and its independence of wavelength to determine the delta-pulse response of a vacuum uv photomultiplier. This photomultiplier was then used to establish the true time profile of a nanosecond H(2) flashlamp. Two numerical techniques (the exponential series method and the fast Fourier transform method) were used to deconvolute the data arising from these experiments. The results indicate that the H(2) flashlamp probably has the same profile in the many-line region, lambda < 1800 A, and in the continuum region, lambda > 2100 A, and the delta-pulse response of the PMT appears consistent with known properties of the Cs-Te photocathode. PMID:20212849

  16. The recent development of an X-ray grating interferometer at Shanghai Synchrotron Radiation Facility

    NASA Astrophysics Data System (ADS)

    Sun, Haohua; Kou, Bingquan; Xi, Yan; Qi, Juncheng; Sun, Jianqi; Mohr, Jürgen; Börner, Martin; Zhao, Jun; Xu, Lisa X.; Xiao, Tiqiao; Wang, Yujie

    2012-07-01

    An X-ray grating interferometer has been installed at Shanghai Synchrotron Radiation Facility (SSRF). Three sets of phase gratings were designed to cover the wide X-ray energy range needed for biological and soft material imaging capabilities. The performance of the grating interferometer has been evaluated by a tomography study of a PMMA particle packing and a new born mouse chest. In the mouse chest study, the carotid artery and carotid vein inside the mouse can be identified in situ without contrast agents.

  17. National Institute of Standards and Technology Synchrotron Radiation Facilities for Materials Science

    PubMed Central

    Long, Gabrielle G.; Allen, Andrew J.; Black, David R.; Burdette, Harold E.; Fischer, Daniel A.; Spal, Richard D.; Woicik, Joseph C.

    2001-01-01

    Synchrotron Radiation Facilities, supported by the Materials Science and Engineering Laboratory of the National Institute of Standards and Technology, include beam stations at the National Synchrotron Light Source at Brookhaven National Laboratory and at the Advanced Photon Source at Argonne National Laboratory. The emphasis is on materials characterization at the microstructural and at the atomic and molecular levels, where NIST scientists, and researchers from industry, universities and government laboratories perform state-of-the-art x-ray measurements on a broad range of materials.

  18. The recent development of an X-ray grating interferometer at Shanghai Synchrotron Radiation Facility

    SciTech Connect

    Sun Haohua; Kou Bingquan; Xi Yan; Qi Juncheng; Sun Jianqi; Mohr, Juergen; Boerner, Martin; Zhao Jun; Xu, Lisa X.; Xiao Tiqiao; Wang Yujie

    2012-07-31

    An X-ray grating interferometer has been installed at Shanghai Synchrotron Radiation Facility (SSRF). Three sets of phase gratings were designed to cover the wide X-ray energy range needed for biological and soft material imaging capabilities. The performance of the grating interferometer has been evaluated by a tomography study of a PMMA particle packing and a new born mouse chest. In the mouse chest study, the carotid artery and carotid vein inside the mouse can be identified in situ without contrast agents.

  19. Diverse Studies in the Reactivated NASA/Ames Radiation Facility: From Shock Layer Spectroscopy to Thermal Protection System Impact

    NASA Technical Reports Server (NTRS)

    Miller, Robert J.; Hartman, G. Joseph (Technical Monitor)

    1994-01-01

    NASA/Ames' Hypervelocity Free-Flight Radiation Facility has been reactivated after having been decommissioned for some 15 years, first tests beginning in early 1994. This paper discusses two widely different studies from the first series, one involving spectroscopic analysis of model shock-layer radiation, and the other the production of representative impact damage in space shuttle thermal protection tiles for testing in the Ames arc-jet facilities. These studies emphasize the interorganizational and interdisciplinary value of the facility in the newly-developing structure of NASA.

  20. Occupational Radiation Exposure at Commercial Nuclear Power Reactors and Other Facilities 2008

    SciTech Connect

    U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research

    2009-12-01

    This report summarizes the occupational exposure data that are maintained in the U.S. Nuclear Regulatory Commission (NRC) Radiation Exposure Information and Reporting System (REIRS). The bulk of the information contained in the report was compiled from the 2008 annual reports submitted by five of the seven categories1 of NRC licensees subject to the reporting requirements of 10 CFR 20.2206. The annual reports submitted by these licensees consist of radiation exposure records for each monitored individual. These records are analyzed for trends and presented in this report in terms of collective dose and the distribution of dose among the monitored individuals. Because there are no geologic repositories for high-level waste currently licensed and no low-level waste disposal facilities in operation, only five categories will be considered in this report.

  1. Multilayer-based soft X-ray polarimeter at the Beijing Synchrotron Radiation Facility

    NASA Astrophysics Data System (ADS)

    Sun, Li-Juan; Cui, Ming-Qi; Zhu, Jie; Zhao, Yi-Dong; Zheng, Lei; Wang, Zhan-Shan; Zhu, Jing-Tao

    2013-07-01

    A compact high precision eight-axis automatism and two-axis manual soft-ray polarimeter with a multilayer has been designed, constructed, and installed in 3W1B at the Beijing Synchrotron Radiation Facility (BSRF). Four operational modes in the same device, which are double-reflection, double-transmission, front-reflection-behind-transmission and front-transmission-behind-reflection, have been realized. It can be used for the polarization analysis of synchrotron radiation. It also can be used to characterize the polarization properties of the optical elements in the soft X-ray energy range. Some experiments with Mo/Si and Cr/C multilayers have been performed by using this polarimeter with good results obtained.

  2. Future radiation measurements in low Earth orbit. [long duration exposure facility

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.

    1992-01-01

    The first Long Duration Exposure Facility (LDEF) mission has demonstrated the value of the LDEF concept for deep surveys of the space radiation environment. This paper will survey the types of measurements that could be done on a second LDEF mission. One of the most surprising discoveries on LDEF1 was the Be-7 that was found imbedded on the windward surface. LDEF2 could follow up on this discovery and search for evidence of other cosmogenic nuclei. Another experiment could be designed to investigate the presence of energetic heavy ions observed on LDEF1. The relative abundance of rare earths can also be used to search for evidence that cosmic rays accelerate in episodes which occur throughout their propagation in the stellar medium. Further investigations of radiation effects could also be undertaken. A second LDEF mission also offers the opportunity for new investigations such as measurements of cosmic ray differential energy spectrum to ultrahigh energies. These and other ideas will be discussed.

  3. The Planck's character and temperature of visible radiation of a pulse-periodic discharge in cesium vapor

    NASA Astrophysics Data System (ADS)

    Baksht, F. G.; Lapshin, V. F.

    2016-02-01

    The radiation spectrum of pulse-periodic discharge in cesium vapor has been simulated in the framework of a two-temperature multifluid radiative gasdynamic model. It is established that, at a broad range of vapor pressures, the discharge spectrum exhibits a Planck character in a significant part of the visible spectral interval, which accounts for the high quality of color rendering in the discharge radiation. The relation between color temperature T c and electron temperature T 0 on the discharge axis is determined by radial optical thickness τ R of the plasma column: T c ≈ T 0 at τ R ≈ 1, T c < T 0 at τ R < 1, and T c > T 0 at τ R > 1. As the vapor pressure increases from 83 to 1087 Torr, color rendering index Ra of the discharge radiation changes from 95 to 98 and the color temperature grows from 3600 to 5200 K.

  4. Generation of high power pulsed terahertz radiation using a plasmonic photoconductive emitter array with logarithmic spiral antennas

    SciTech Connect

    Berry, Christopher W.; Hashemi, Mohammad R.; Jarrahi, Mona

    2014-02-24

    An array of 3 × 3 plasmonic photoconductive terahertz emitters with logarithmic spiral antennas is fabricated on a low temperature (LT) grown GaAs substrate and characterized in response to a 200 fs optical pump from a Ti:sapphire mode-locked laser at 800 nm wavelength. A microlens array is used to split and focus the optical pump beam onto the active area of each plasmonic photoconductive emitter element. Pulsed terahertz radiation with record high power levels up to 1.9 mW in the 0.1–2 THz frequency range is measured at an optical pump power of 320 mW. The record high power pulsed terahertz radiation is enabled by the use of plasmonic contact electrodes, enhancing the photoconductor quantum efficiencies, and by increasing the overall device active area, mitigating the carrier screening effect and thermal breakdown at high optical pump power levels.

  5. Neutrons confirmed in Nagasaki and at the Army Pulsed Radiation Facility: implications for Hiroshima.

    PubMed

    Straume, T; Harris, L J; Marchetti, A A; Egbert, S D

    1994-05-01

    Recent reports have clearly demonstrated that large discrepancies exist between neutron activation measured in Hiroshima and activation calculated using the current dosimetry system, DS86. The reports confirmed previous results for cobalt activation in Hiroshima that suggested problems, and this has spurred a joint U.S.-Japan effort to identify the source(s) of this discrepancy. Here, new results are presented that appear to eliminate both the measurements of neutron activation and the DS86 air-transport calculations as potential sources of the discrepancy in Hiroshima. Computer transport of DS86 fission neutrons through large distances of air was validated using concrete samples from Nagasaki and chloride detectors placed at selected distances from a bare uranium reactor. In both cases, accelerator mass spectrometry was used to measure thermal neutron activation via the reaction, 35Cl(n, gamma)36Cl (half-life, 301,000 years). Good agreement was observed between measurements of neutron activation and DS86 calculations for Nagasaki, as well as for the reactor experiment. Thus the large discrepancy observed in Hiroshima appears not to be due to uncertainties in air-transport calculations or in the activation measurements; rather, the discrepancy appears to be due to uncertainties associated with the Hiroshima bomb itself. PMID:8183989

  6. Drilling and cutting of thin metal plates in water with radiation of a repetitively pulsed Nd : YAG laser

    NASA Astrophysics Data System (ADS)

    Glova, A. F.; Lysikov, A. Yu

    2011-10-01

    The conditions of drilling and cutting of 0.15-mm-thick titanium and stainless steel plates in water with the radiation of a repetitively pulsed Nd : YAG laser having the mean power up to 30 W are studied experimentally in the absence of water and gas jets. Dependences of the maximal cutting speed in water on the radiation power are obtained, the cutting efficiency is determined, and the comparison with the conditions of drilling and cutting of plates in air is carried out.

  7. Generation of widely tunable intense far-infrared radiation pulses by stimulated Raman transitions in methylfluoride gas

    SciTech Connect

    Lang, P.T.; Sessler, F.; Werling, U.; Renk, K.F. )

    1989-12-18

    We report on the generation of widely tunable intense far-infrared radiation pulses by stimulated Raman transitions in methylfluoride gas. Using a tunable high-pressure CO{sub 2} laser we achieved, by {ital P}-branch tuning of stimulated Raman transitions in {sup 12}CH{sub 3}F and {sup 13}CH{sub 3}F gases, tunable generation of radiation in a series of intervals in the spectral range from 37 to 72 cm{sup {minus}1} covering 20% of this range. Possibilities of further extension of the tuning regions are also discussed.

  8. The structure and photoconductivity of SiGe/Si epitaxial layers modified by single-pulse laser radiation

    NASA Astrophysics Data System (ADS)

    Ivlev, G. D.; Kazuchits, N. M.; Prakopyeu, S. L.; Rusetsky, M. S.; Gaiduk, P. I.

    2014-12-01

    The effect of nanosecond pulses of ruby laser radiation on the structural state and morphology of the epitaxial layers of a SiO0.5Ge0.5 solid solution on silicon with the initiation of a crystal-melt phase transition has been studied by electron microscopy. Data on the photoelectric parameters of the laser-modified layers having a cellular structure owing to the segregation of germanium during the solidification of the binary melt have been derived.

  9. High-efficiency generation of pulsed Lyman-α radiation by resonant laser wave mixing in low pressure Kr-Ar mixture.

    PubMed

    Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Louchev, Oleg A; Iwasaki, Masahiko; Wada, Satoshi

    2016-04-01

    We report an experimental generation of ns pulsed 121.568 nm Lyman-α radiation by the resonant nonlinear four-wave mixing of 212.556 nm and 845.015 nm radiation pulses providing a high conversion efficiency 1.7x10-3 with the output pulse energy 3.6 μJ achieved using a low pressure Kr-Ar mixture. Theoretical analysis shows that this efficiency is achieved due to the advantage of using (i) the high input laser intensities in combination with (ii) the low gas pressure allowing us to avoid the onset of full-scale discharge in the laser focus. In particular, under our experimental conditions the main mechanism of photoionization caused by the resonant 2-photon 212.556 nm radiation excitation of Kr atoms followed by the 1-photon ionization leads to ≈17% loss of Kr atoms and efficiency loss only by the end of the pulse. The energy of free electrons, generated by 212.556 nm radiation via (2 + 1)-photon ionization and accelerated mainly by 845.015 nm radiation, remains during the pulse below the level sufficient for the onset of full-scale discharge by the electron avalanche. Our analysis also suggests that ≈30-fold increase of 845.015 nm pulse energy can allow one to scale up the L-α radiation pulse energy towards the level of ≈100 μJ. PMID:27137045

  10. Repetitively pulsed UV radiation source based on a run-away electron preionised diffuse discharge in nitrogen

    NASA Astrophysics Data System (ADS)

    Baksht, E. Kh; Burachenko, A. G.; Lomaev, M. I.; Panchenko, A. N.; Tarasenko, V. F.

    2015-04-01

    An extended repetitively pulsed source of spontaneous UV radiation is fabricated, which may also be used for producing laser radiation. Voltage pulses with an incident wave amplitude of up to 30 kV, a half-amplitude duration of ~4 ns and a rise time of ~2.5 ns are applied to a gap with a nonuniform electric field. For an excitation region length of 35 cm and a nitrogen pressure of 30 - 760 Torr, a diffusive discharge up to a pulse repetition rate of 2 kHz is produced without using an additional system for gap preionisation. An investigation is made of the plasma of the run-away electron preionised diffuse discharge. Using a CCD camera it is found that the dense diffused plasma fills the gap in a time shorter than 1 ns. X-ray radiation is recorded from behind the foil anode throughout the pressure range under study; a supershort avalanche electron beam is recorded by the collector electrode at pressures below 100 Torr.

  11. Performance of high-convergence, layered DT implosions with extended-duration pulses at the National Ignition Facility.

    PubMed

    Smalyuk, V A; Atherton, L J; Benedetti, L R; Bionta, R; Bleuel, D; Bond, E; Bradley, D K; Caggiano, J; Callahan, D A; Casey, D T; Celliers, P M; Cerjan, C J; Clark, D; Dewald, E L; Dixit, S N; Döppner, T; Edgell, D H; Edwards, M J; Frenje, J; Gatu-Johnson, M; Glebov, V Y; Glenn, S; Glenzer, S H; Grim, G; Haan, S W; Hammel, B A; Hartouni, E P; Hatarik, R; Hatchett, S; Hicks, D G; Hsing, W W; Izumi, N; Jones, O S; Key, M H; Khan, S F; Kilkenny, J D; Kline, J L; Knauer, J; Kyrala, G A; Landen, O L; Le Pape, S; Lindl, J D; Ma, T; MacGowan, B J; Mackinnon, A J; MacPhee, A G; McNaney, J; Meezan, N B; Moody, J D; Moore, A; Moran, M; Moses, E I; Pak, A; Parham, T; Park, H-S; Patel, P K; Petrasso, R; Ralph, J E; Regan, S P; Remington, B A; Robey, H F; Ross, J S; Spears, B K; Springer, P T; Suter, L J; Tommasini, R; Town, R P; Weber, S V; Widmann, K

    2013-11-22

    Radiation-driven, low-adiabat, cryogenic DT layered plastic capsule implosions were carried out on the National Ignition Facility (NIF) to study the sensitivity of performance to peak power and drive duration. An implosion with extended drive and at reduced peak power of 350 TW achieved the highest compression with fuel areal density of ~1.3±0.1 g/cm2, representing a significant step from previously measured ~1.0 g/cm2 toward a goal of 1.5 g/cm2. Future experiments will focus on understanding and mitigating hydrodynamic instabilities and mix, and improving symmetry required to reach the threshold for thermonuclear ignition on NIF. PMID:24313493

  12. Non Evaporable Getter (NEG) Coatings for Vacuum Systems in Synchrotron Radiation Facilities

    SciTech Connect

    Manini, Paolo; Conte, Andrea; Raimondi, Stefano; Bonucci, Antonio

    2007-01-19

    Non evaporable Getter (NEG) films, sputter deposited onto the internal surfaces of vacuum chambers, have been proposed by CERN to substantially reduce the gas pressure in UHV-XHV systems. The NEG film acts as a conductance-free distributed pump inside a chamber. Being a barrier for gases it also reduces thermal out-gassing, thus allowing the achievement of very demanding pressure conditions. These features are ideal for very narrow, conductance limited chambers, like Insertion Devices, which cannot be always efficiently pumped by ordinary means. Recent investigations have also shown that NEG coatings do present additional interesting features, like low secondary electron yield and low gas de-sorption rates under ions, electrons and photons bombardment, compared to traditional technical surfaces. Experimental tests, carried out in several high energy machines and synchrotron radiations facilities have so far confirmed the benefits of NEG films in term of better vacuum, longer beam life time and stability, simplified machine design, reduced conditioning time and overall improved machine performances. For these reasons, NEG coating technology is now gaining increasing attention and it is seriously considered for upgrades in a number of machines and for future projects. In the present paper, we report SAES getters experience on NEG coating of chambers of different geometries, materials and sizes for a variety of projects related to synchrotron radiation facilities. Examples of applications in various machines, as well as typical issues related to chambers preparation, film deposition, quality control and characterization, are given.

  13. Non Evaporable Getter (NEG) Coatings for Vacuum Systems in Synchrotron Radiation Facilities

    NASA Astrophysics Data System (ADS)

    Manini, Paolo; Conte, Andrea; Raimondi, Stefano; Bonucci, Antonio

    2007-01-01

    Non evaporable Getter (NEG) films, sputter deposited onto the internal surfaces of vacuum chambers, have been proposed by CERN to substantially reduce the gas pressure in UHV-XHV systems. The NEG film acts as a conductance-free distributed pump inside a chamber. Being a barrier for gases it also reduces thermal out-gassing, thus allowing the achievement of very demanding pressure conditions. These features are ideal for very narrow, conductance limited chambers, like Insertion Devices, which cannot be always efficiently pumped by ordinary means. Recent investigations have also shown that NEG coatings do present additional interesting features, like low secondary electron yield and low gas de-sorption rates under ions, electrons and photons bombardment, compared to traditional technical surfaces. Experimental tests, carried out in several high energy machines and synchrotron radiations facilities have so far confirmed the benefits of NEG films in term of better vacuum, longer beam life time and stability, simplified machine design, reduced conditioning time and overall improved machine performances. For these reasons, NEG coating technology is now gaining increasing attention and it is seriously considered for upgrades in a number of machines and for future projects. In the present paper, we report SAES getters experience on NEG coating of chambers of different geometries, materials and sizes for a variety of projects related to synchrotron radiation facilities. Examples of applications in various machines, as well as typical issues related to chambers preparation, film deposition, quality control and characterization, are given.

  14. Influence of Capsule Offset on Radiation Asymmetry in Shenguang-II Laser Facility

    NASA Astrophysics Data System (ADS)

    Jing, Longfei; Li, Hang; Lin, Zhiwei; Li, Liling; Kuang, Longyu; Huang, Yunbao; Zhang, Lu; Huang, Tianxuan; Jiang, Shao'en; Ding, Yongkun

    2015-10-01

    The re-emitted images of the frame camera indicated that the high-Z (Bi) capsule deviated about 29 μm from the center of the hohlraum in experiments at the Shenguang-II (SG-II) laser facility; however, investigations on this issue have seldom been performed. The influence of three dimensional offsets of a capsule on its radiation asymmetry in inertial confinement fusion (ICF) will be analyzed in this paper. Simulations demonstrate that the axial offset of 100 μm of a capsule from the center of the hohlraum brings an additional 3.5% radiation drive asymmetry and 6.5% P1 asymmetry (Legendre odd model) on the capsule in the SG-II laser facility, and the offset must be within 25 μm if the P1 asymmetry is restricted to below 2%. supported by Science and Technology on Plasma Physics Laboratory of China (Nos. 9140C680104140C68287, 9140C680104130C68241), and in part by National Natural Science Foundation of China (Nos. 11475154, 51375185, U1430124, 11435011, 11305160)

  15. NIST Accelerator Facilities And Programs In Support Of Industrial Radiation Research

    SciTech Connect

    Bateman, F.B.; Desrosiers, M.F.; Hudson, L.T.; Coursey, B.M.; Bergstrom, P.M. Jr.; Seltzer, S.M.

    2003-08-26

    NIST's Ionizing Radiation Division maintains and operates three electron accelerators used in a number of applications including waste treatment and sterilization, radiation hardness testing, detector calibrations and materials modification studies. These facilities serve a large number of governmental, academic and industrial users as well as an active intramural research program. They include a 500 kV cascaded-rectifier accelerator, a 2.5 MV electron Van de Graaff accelerator and a 7 to 32 MeV electron linac, supplying beams ranging in energy from a few keV up to 32 MeV. In response to the recent anthrax incident, NIST along with the US Postal Service and the Armed Forces Radiobiology Research Institute (AFRRI) are working to develop protocols and testing procedures for the USPS mail sanitization program. NIST facilities and personnel are being employed in a series of quality-assurance measurements for both electron- and photon-beam sanitization. These include computational modeling, dose verification and VOC (volatile organic compounds) testing using megavoltage electron and photon sources.

  16. Personal radiation doses in PET/CT facility: measurements vs. calculations.

    PubMed

    Hippeläinen, E; Nikkinen, P; Ihalainen, T; Uusi-Simola, J; Savolainen, S

    2008-01-01

    The estimation of shielding requirement of a new positron emission tomography (PET) facility is essential. Because of penetrating annihilation photons, not only radiation safety in the vicinity of patients should be considered, but also rooms adjacent to uptake and imaging rooms should be taken into account. Before installing a PET/CT camera to nuclear medicine facilities of Helsinki University Central Hospital (HUCH), a typical PET imaging day was simulated using phantoms. Phantoms were filled with 300 +/- 36 MBq of (18)F isotope and dose rates were measured at 12 central locations in the laboratory. In addition to measurements, dose rates were also calculated using guidelines of AAPM Task Group 108. The relationship between the measured and calculated dose rates was found to be good and statistically significant, using Pearson's correlation test. The evaluated monthly doses were compared with personal dosemeter readings. AAPM's report gives practical tools for evaluation of radiation shielding. Calculations can be carried out successfully for existing hospital complexes too. However, calculations should be carried out carefully, because especially doors, windows and partitions can easily cause underestimation of shielding requirements as shown in this work. PMID:18713782

  17. Study of pulsed neon-xenon VUV radiating low pressure plasmas for mercury free fluorescent sign optimization

    NASA Astrophysics Data System (ADS)

    Robert, E.; Point, S.; Dozias, S.; Viladrosa, R.; Pouvesle, J. M.

    2010-04-01

    This work deals with the study and optimization of mercury free fluorescent discharge tubes for publicity lighting applications. The experimental set-up allows for time resolved spectroscopy from 110 up to 900 nm, photometric characterization in a large volume integrating sphere and the current and voltage measurement of microsecond duration signals delivered by lab-developed pulsed drivers. The glow and afterglow radiative process analysis indicates that the best performance measured with the pulsed excitation of rare gas plasma, in comparison with the conventional ac excitation, essentially originates from the efficient plasma relaxation during the afterglow at the benefit of the vacuum ultraviolet (VUV) resonance line radiated at 146.9 nm for xenon. The fit of the VUV time resolved experimental measurements, with the results issued from a simplified kinetic model of neon-xenon plasmas, evidences the crucial role of production of molecular ions during the glow phase and of their radiative recombination during the afterglow. The pulse duration and the gas mixture pressure appear as two experimental parameters whose influence, studied over an extended range, has been demonstrated to bring about a significant sign performance enhancement. There exists an optimum pulse duration range, which results in the appearance of limited stepwise excitation and ionization processes, favourable for an intense afterglow VUV production. The pressure dependence study shows that the best performance for pulsed excitation is obtained in Ne/Xe (100/1) mixtures around 50 mbar, at the difference of an ac driven Ne/Xe plasma for which the best conditions were reported to be of a few millibars. This pressure increase results both in the VUV and sign light output enhancement and the successful continuous operation of pulsed mercury free signs for time as long as 4000 h with neither electrode erosion, nor glass or phosphor degradation nor chromatic coordinate variation. For the green

  18. Scattering of an ultrashort electromagnetic radiation pulse by an atom in a broad spectral range

    SciTech Connect

    Astapenko, V. A.

    2011-02-15

    The scattering of an ultrashort electromagnetic pulse by atomic particles is described using a consistent quantum-mechanical approach taking into account excitation of a target and nondipole electromagnetic interaction, which is valid in a broad spectral range. This approach is applied to the scattering of single- and few-cycle pulses by a multielectron atom and a hydrogen atom. Scattering spectra are obtained for ultrashort pulses of different durations. The relative contribution of 'elastic' scattering of a single-cycle pulse by a hydrogen atom is studied in the high-frequency limit as a function of the carrier frequency and scattering angle.

  19. The status of the macromolecular crystallography beamlines at the European Synchrotron Radiation Facility

    NASA Astrophysics Data System (ADS)

    Mueller-Dieckmann, Christoph; Bowler, Matthew W.; Carpentier, Philippe; Flot, David; McCarthy, Andrew A.; Nanao, Max H.; Nurizzo, Didier; Pernot, Petra; Popov, Alexander; Round, Adam; Royant, Antoine; de Sanctis, Daniele; von Stetten, David; Leonard, Gordon A.

    2015-04-01

    The European Synchrotron Radiation Facility (ESRF) is the oldest and most powerful 3rd generation synchrotron in Europe, providing X-rays to more than 40 experimental stations welcoming several thousand researchers per year. A major success story has been the ESRF's facilities for macromolecular crystallography (MX). These are grouped around 3 straight sections: On ID23 canted undulators accommodate ID23-1, a mini-focus tuneable energy end station and ID23-2, the world's first micro-focus beamline dedicated to MX; ID29 houses a single, mini-focus, tuneable energy end station; ID30 will provide three end stations for MX due in operation from mid-2014 to early 2015. Here, one branch of a canted X-ray source feeds two fixed-energy end stations (MASSIF-1, MASSIF-3). The second feeds ID30B, a variable focus, tuneable energy beamline. MASSIF-1 is optimised for automatic high-throughput experiments requiring a relatively large beam size at the sample position, MASSIF-3 is a high-intensity, micro-focus facility designed to complement ID23-2. All end stations are highly automated, equipped with sample mounting robots and large area, fast-readout photon-counting detectors. Experiment control and tracking is achieved via a combination of the MXCuBE2 graphical user interface and the ISPyB database, the former allowing user-friendly control of all beamline components, the latter providing data tracking before, after and during experiments.

  20. Determining the hohlraum radiation temperature and M-band fraction by using shock wave technique on SGIII-prototype laser facility

    NASA Astrophysics Data System (ADS)

    Huo, Wenyi; Lan, Ke; Li, Yongsheng; Yang, Dong; Li, Sanwei

    2012-10-01

    Experiments have been conducted on SGIII-prototype laser facility using tow materials Al and Ti as shock wave witness plates. The radiation temperature ^TR and M-band fraction fM inside a hohlraum are determined by using the observed shock velocities in Al and Ti. This is the first experimental demonstration of the proposal that ^TR and fM can be simultaneously determined by using shock wave technique [Y. S. Li, et al., Phys. Plasmas 18, 022701 (2011)]. For the Au hohlraum used in the experiments, TR is about 160 eV and ^fM is around 4.3% under a 1 ns laser pulse of 2 kJ. The results from this technique are complementary to those from the broadband soft x-ray spectrometer (SXS), and the technique can be used to determine ^TR and fM inside an ignition hohlraum.

  1. Effect of surface-breakdown plasma on metal drilling by pulsed CO2-laser radiation

    NASA Astrophysics Data System (ADS)

    Arutiunian, P. V.; Baranov, V. Iu.; Bobkov, I. V.; Bol'Shakov, L. A.; Dolgov, V. A.

    1988-03-01

    The effect of low-threshold surface breakdown produced by short (5-microsec) CO2-laser pulses on the metal drilling process is investigated. Data on the interaction of metals with laser pulses having the same duration but different shape are shown to be different. The effect of the ambient atmospheric pressure on the laser drilling process is investigated.

  2. The PUR Experiment on the EXPOSE-R facility: biological dosimetry of solar extraterrestrial UV radiation

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Egyeki, M.; Fekete, A.; Horneck, G.; Kovács, G.; Panitz, C.

    2015-01-01

    The aim of our experiment Phage and Uracil Response was to extend the use of bacteriophage T7 and uracil biological dosimeters for measuring the biologically effective ultraviolet (UV) dose in the harsh extraterrestrial radiation conditions. The biological detectors were exposed in vacuum-tightly cases in the European Space Agency (ESA) astrobiological exposure facility attached to the external platform of Zvezda (EXPOSE-R). EXPOSE-R took off to the International Space Station (ISS) in November 2008 and was installed on the External platform of the Russian module Zvezda of the ISS in March 2009. Our goal was to determine the dose-effect relation for the formation of photoproducts (i.e. damage to phage DNA and uracil, respectively). The extraterrestrial solar UV radiation ranges over the whole spectrum from vacuum-UV (λ<200 nm) to UVA (315 nm<λ<400 nm), which causes photolesions (photoproducts) in the nucleic acids/their components either by photoionization or excitation. However, these wavelengths cause not only photolesions but in a wavelength-dependent efficiency the reversion of some photolesions, too. Our biological detectors measured in situ conditions the resultant of both reactions induced by the extraterrestrial UV radiation. From this aspect the role of the photoreversion in the extension of the biological UV dosimetry are discussed.

  3. Reaching white-light radiation source of ultrafast laser pulses with tunable peak power using nonlinear self-phase modulation in neon gas

    NASA Astrophysics Data System (ADS)

    Tawfik, Walid

    2016-08-01

    A source of white-light radiation that generates few-cycle pulses with controlled peak power values has been developed. These ultrafast pulses have been observed by spectral broadening of 32 fs pulses through nonlinear self-phase modulation in a neon-filled hollow-fiber then compressed with a pair of chirped mirrors for dispersion compensation. The observed pulses reached transform-limited duration of 5.77 fs and their peak power values varied from 57 GW up to 104 GW at repetition rate of 1 kHz. Moreover, the applied method is used for a direct tuning of the peak power of the output pulses through varying the chirping of the input pulses at different neon pressures. The observed results may give an opportunity to control the ultrafast interaction dynamics on the femtosecond time scale and facilitate the regeneration of attosecond pulses.

  4. The hohlraum radiation temperature and M-band fraction on the SGIII-prototype laser facility

    NASA Astrophysics Data System (ADS)

    Huo, Wenyi; Yang, Dong; Lan, Ke; Li, Sanwei; Li, Yongsheng

    2014-10-01

    The hohlraum radiation temperature and M-band fraction are determined by a shock-wave technique and measured by a broadband soft x-ray spectrometer. The peak radiation temperature TR and M-band fraction fm are simultaneously determined by using the observed shock velocities in Al and Ti. For the vacuum Au hohlraum used in the experiments, TR is about 160 eV and fm is between 4.3-6.3% under 1ns laser pulse of 2 k. And TR is about 202 eV and fm is about 9% with laser energy 6 kJ. The Continuous Phase Plate (CPP) for beam smoothing is applied in the experiment, which increases TR to 207 eV while has almost no influence on fm. Comparisons between the results from the two kinds of technologies show that TR from the shock wave technique is lower than that from SXS whether CPP is applied or not. However, fm from the shock wave technique is consistent with that from SXS without CPP, but obviously lower than the SXS's result with CPP.

  5. [Pulse-modulated Electromagnetic Radiation of Extremely High Frequencies Protects Cellular DNA against Damaging Effect of Physico-Chemical Factors in vitro].

    PubMed

    Gapeyev, A B; Lukyanova, N A

    2015-01-01

    Using a comet assay technique, we investigated protective effects of. extremely high frequency electromagnetic radiation in combination with the damaging effect of X-ray irradiation, the effect of damaging agents hydrogen peroxide and methyl methanesulfonate on DNA in mouse whole blood leukocytes. It was shown that the preliminary exposure of the cells to low intensity pulse-modulated electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20-min exposure, modulation frequencies of 1 and 16 Hz) caused protective effects decreasing the DNA damage by 20-45%. The efficacy of pulse-modulated electromagnetic radiation depended on the type of genotoxic agent and increased in a row methyl methanesulfonate--X-rays--hydrogen peroxide. Continuous electromagnetic radiation was ineffective. The mechanisms of protective effects may be connected with an induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated electromagnetic radiation. PMID:26591599

  6. Atmospheric Radiation Measurement Program Climate Research Facility Operation quarterly report July 1 - September 30, 2010.

    SciTech Connect

    Sisterson, D. L.

    2010-10-26

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the fourth quarter of FY2010 for the Southern Great Plains (SGP) site is 2097.60 hours (0.95 2208 hours this quarter). The OPSMAX for the North Slope of Alaska (NSA) locale is 1987.20 hours (0.90 2208) and for the Tropical Western Pacific (TWP) locale is 1876.80 hours (0.85 2208). The first ARM Mobile Facility (AMF1) deployment in Graciosa Island, the Azores, Portugal, continues, so the OPSMAX time this quarter is 2097.60 hours (0.95 x 2208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or datastream. Data availability reported here refers to the average of the individual, continuous datastreams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to

  7. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report. October 1 - December 31, 2009.

    SciTech Connect

    D. L. Sisterson

    2010-01-12

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2010 for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208); for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208); and for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 x 2,208). The ARM Mobile Facility (AMF) deployment in Graciosa Island, the Azores, Portugal, continues; its OPSMAX time this quarter is 2,097.60 hours (0.95 x 2,208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are the result of downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to

  8. Transformation of the spatial coherence of pulsed laser radiation transmitted in the nonlinear regime through a multimode graded-index fibre

    SciTech Connect

    Kitsak, A I; Kitsak, M A

    2006-01-31

    A method is proposed for transformation of the spatial coherence of pulsed laser radiation upon nonlinear interaction in a multimode fibre. The specific features of the transmission of correlation properties of radiation in a graded-index fibre with regular and irregular profiles of the refractive index of the fibre core are analysed. A comparative analysis of the parameter of global degree of radiation coherence at the output of inhomogeneous waveguide and non-waveguide media is performed. It is shown that the most efficient mechanism of decorrelation of pulsed radiation in an optical fibre is fluctuations of the phase of radiation scattered by inhomogeneities of the refractive index of the fibre core induced due to nonlinear interaction with radiation with the spatially inhomogeneous intensity distribution. (control of laser radiation parameters)

  9. Pump-probe studies of radiation induced defects and formation of warm dense matter with pulsed ion beams

    NASA Astrophysics Data System (ADS)

    Schenkel, T.; Persaud, A.; Gua, H.; Seidl, P. A.; Waldron, W. L.; Gilson, E. P.; Kaganovich, I. D.; Davidson, R. C.; Friedman, A.; Barnard, J. J.; Minior, A. M.

    2014-10-01

    We report results from the 2nd generation Neutralized Drift Compression Experiment at Berkeley Lab. NDCX-II is a pulsed, linear induction accelerator designed to drive thin foils to warm dense matter (WDM) states with peak temperatures of ~ 1 eV using intense, short pulses of 1.2 MeV lithium ions. Tunability of the ion beam enables pump-probe studies of radiation effects in solids as a function of excitation density, from isolated collision cascades to the onset of phase-transitions and WDM. Ion channeling is an in situ diagnostic of damage evolution during ion pulses with a sensitivity of <0.1% displacements per atom. We will report results from damage evolution studies in thin silicon crystals with Li + and K + beams. Detection of channeled ions tracks lattice disorder evolution with a resolution of ~ 1 ns using fast current measurements. We will discuss pump-probe experiments with pulsed ion beams and the development of diagnostics for WDM and multi-scale (ms to fs) access to the materials physics of collision cascades e.g. in fusion reactor materials. Work performed under auspices of the US DOE under Contract No. DE-AC02-05CH11231.

  10. Roles of Interfering Radiation Emitted from Decaying Pulses Obeying Soliton Equations Belonging to the Ablowitz-Kaup-Newell-Segur Systems

    NASA Astrophysics Data System (ADS)

    Fujishima, Hironobu; Yajima, Tetsu

    2015-06-01

    The nonlinear Schrödinger (NLS) equation under the box-type initial condition, which models general multiple pulses deviating from pure solitons, is analyzed. Following the approximation by splitting the initial pulse into many small bins [G. Boffetta and A. R. Osborne, J. Comp. Phys. 102, 252 (1992)], we can analyze the Zakharov-Shabat eigenvalue problem to construct transfer matrices connecting the Jost functions in each interval without direct numerical computation. We can obtain analytical expressions for the scattering data that describe interfering radiation emitted from initial pulses. The number of solitons that appear in the final stage is predicted theoretically, and the condition generating an unusual wave such as a double-pole soliton is derived. Numerical analyses under box-type initial conditions are also performed to show that the interplay between the tails from decaying pulses can affect the asymptotic profile.

  11. Pulsed reactor experiments at Oak Ridge

    SciTech Connect

    Mihalczo, J.T.

    1994-12-31

    This paper describes dynamic experiments for 3 pulsed reactors. 1st reactor was pulsed from some average power by rotating a partial Be reflector past an unreflected core face; the other 2 reactors were pulsed by rapid insertion of a fuel rod into the unmoderated and unreflected reactor at essentially zero neutron level with no significant neutron source present. The first reactor was a mockup of an EURATOM design (never constructed) of the proposed SORA Reactor, and the other two were the Health Physics Research Reactor and the Army Pulse Radiation Facility Reactor (APRFR). This paper describes the experiments performed in initial testing of these systems, including destructive tests of APRFR, to set operating limits for this type of reactor in pulsed operation. All the experiments described were performed at the Oak Ridge Critical Experiments Facility.

  12. Shape profile of acoustic radiation-induced static displacement pulses in solids

    NASA Astrophysics Data System (ADS)

    Cantrell, John H.; Yost, William T.

    2010-07-01

    In a recent article Narasimha et al. [J. Appl. Phys. 105, 073506 (2009)] claim to show that the shape of static displacement pulses generated by ultrasonic tone-bursts in nondispersive solids is that of a growing trapezoid in the spatial domain that leads to a flat-topped pulse shape in the time domain for a fixed spatial position. Flaws in their theoretical arguments are corrected to show that their model actually predicts a right-triangular pulse shape for nondispersive monocrystals in both the spatial and time domains as originally reported by Yost and Cantrell [Phys. Rev. B 30, 3221 (1984)] and Cantrell et al. [Phys. Rev. B 35, 9780 (1987)].

  13. Quantifying immediate radiative forcing by black carbon and organic matter with the Specific Forcing Pulse

    NASA Astrophysics Data System (ADS)

    Bond, T. C.; Zarzycki, C.; Flanner, M. G.; Koch, D. M.

    2010-06-01

    We propose a measure to quantify climate warming or cooling by pollutants with atmospheric lifetimes of less than one year: the Specific Forcing Pulse (SFP). SFP is the amount of energy added to the Earth system per mass of pollutant emitted. Global average SFP for black carbon, including atmosphere and cryosphere, is 1.12 GJ g-1 and that for organic matter is -0.061 GJ g-1. We provide regional values for black carbon (BC) and organic matter (OM) emitted from 23 source-region combinations, divided between atmosphere and cryosphere impacts and identifying forcing by latitude. Regional SFP varies by about 40% for black carbon. This variation is relatively small because of compensating effects; particles from regions that affect ice albedo typically have shorter atmospheric lifetimes because of lower convection. The ratio between BC and OM SFP implies that, for direct forcing, an OM:BC mass ratio of 15 has a neutral effect on top-of-atmosphere direct forcing for any region, and any lower ratio induces direct warming. However, important processes, particularly cloud changes that tend toward cooling, have not been included here. We demonstrate ensemble adjustment, in which we produce a "best estimate" by combining a suite of diverse but simple models and enhanced models of greater complexity. Adjustments for black carbon internal mixing and for regional variability are discussed; regions with convection are implicated in greater model diversity. SFP expresses scientific uncertainty and separates it from policy uncertainty; the latter is caused by disagreements about the relevant time horizon, impact, or spatial scale of interest. However, metrics used in policy discussions, such as global warming potentials, are easily derived from SFP. Global-average SFP for biofuel and fossil fuel emissions translates to a 100-year GWP of about 760 for black carbon and -40 for organic matter when snow forcing is included. Ensemble-adjusted estimates of atmospheric radiative impact by

  14. The Advanced Photon Source: A national synchrotron radiation research facility at Argonne National Laboratory

    SciTech Connect

    1995-10-01

    The vision of the APS sprang from prospective users, whose unflagging support the project has enjoyed throughout the decade it has taken to make this facility a reality. Perhaps the most extraordinary aspect of synchrotron radiation research, is the extensive and diverse scientific makeup of the user community. From this primordial soup of scientists exchanging ideas and information, come the collaborative and interdisciplinary accomplishments that no individual alone could produce. So, unlike the solitary Roentgen, scientists are engaged in a collective and dynamic enterprise with the potential to see and understand the structures of the most complex materials that nature or man can produce--and which underlie virtually all modern technologies. This booklet provides scientists and laymen alike with a sense of both the extraordinary history of x-rays and the knowledge they have produced, as well as the potential for future discovery contained in the APS--a source a million million times brighter than the Roentgen tube.

  15. A facile synthesis of metal nanoparticle - graphene composites for better absorption of solar radiation

    NASA Astrophysics Data System (ADS)

    Sharma, Bindu; Mulla, Rafiq; Rabinal, M. K.

    2015-06-01

    Herein, a facile chemical approach has been adopted to prepare silver nanoparticles (AgNPs)- graphene (G) composite to study photothermal effect. Sodium borohydride (SBH), a strong reducing agent has been selected for this work. Effect of SBH concentrations on optical behavior of AgNPs-G composite was also investigated. Resultant materials were characterized by various techniques including X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), optical absorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM micrographs confirm wrapping of AgNPs into graphene whereas XRD analysis reveals their particle size variation between 47 nm to 69 nm. Optical studies throw a light on their strong absorption behavior towards solar radiation.

  16. X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

    DOE PAGESBeta

    Fournier, K. B.; Brown, Jr., C. G.; Yeoman, M. F.; Fisher, J. H.; Seiler, S. W.; Hinshelwood, D.; Compton, S.; Holdener, F. R.; Kemp, G. E.; Newlander, C. D.; et al

    2016-08-10

    Our team has developed an experimental platform to evaluate the x-ray-generated stress and impulse in materials. Experimental activities include x-ray source development, design of the sample mounting hardware and sensors interfaced to the NIF’s diagnostics insertion system, and system integration into the facility. This paper focuses on the X-ray Transport and Radiation Response Assessment (XTRRA) test cassettes built for these experiments. The test cassette is designed to position six samples at three predetermined distances from the source, each known to within ±1% accuracy. Built in calorimeters give in situ measurements of the x-ray environment along the sample lines of sight.more » We discuss the measured accuracy of sample responses, as well as planned modifications to the XTRRA cassette.« less

  17. A facile synthesis of metal nanoparticle - graphene composites for better absorption of solar radiation

    SciTech Connect

    Sharma, Bindu; Mulla, Rafiq; Rabinal, M. K.

    2015-06-24

    Herein, a facile chemical approach has been adopted to prepare silver nanoparticles (AgNPs)- graphene (G) composite to study photothermal effect. Sodium borohydride (SBH), a strong reducing agent has been selected for this work. Effect of SBH concentrations on optical behavior of AgNPs-G composite was also investigated. Resultant materials were characterized by various techniques including X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), optical absorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM micrographs confirm wrapping of AgNPs into graphene whereas XRD analysis reveals their particle size variation between 47 nm to 69 nm. Optical studies throw a light on their strong absorption behavior towards solar radiation.

  18. Generation of high-photon flux-coherent soft x-ray radiation with few-cycle pulses.

    PubMed

    Demmler, Stefan; Rothhardt, Jan; Hädrich, Steffen; Krebs, Manuel; Hage, Arvid; Limpert, Jens; Tünnermann, Andreas

    2013-12-01

    We present a tabletop source of coherent soft x-ray radiation with high-photon flux. Two-cycle pulses delivered by a fiber-laser-pumped optical parametric chirped-pulse amplifier operating at 180 kHz repetition rate are upconverted via high harmonic generation in neon to photon energies beyond 200 eV. A maximum photon flux of 1.3·10(8) photons/s is achieved within a 1% bandwidth at 125 eV photon energy. This corresponds to a conversion efficiency of ~10(-9), which can be reached due to a gas jet simultaneously providing a high target density and phase matching. Further scaling potential toward higher photon flux as well as higher photon energies are discussed. PMID:24281507

  19. Physical processes at work in sub-30 fs, PW laser pulse-driven plasma accelerators: Towards GeV electron acceleration experiments at CILEX facility

    NASA Astrophysics Data System (ADS)

    Beck, A.; Kalmykov, S. Y.; Davoine, X.; Lifschitz, A.; Shadwick, B. A.; Malka, V.; Specka, A.

    2014-03-01

    Optimal regimes and physical processes at work are identified for the first round of laser wakefield acceleration experiments proposed at a future CILEX facility. The Apollon-10P CILEX laser, delivering fully compressed, near-PW-power pulses of sub-25 fs duration, is well suited for driving electron density wakes in the blowout regime in cm-length gas targets. Early destruction of the pulse (partly due to energy depletion) prevents electrons from reaching dephasing, limiting the energy gain to about 3 GeV. However, the optimal operating regimes, found with reduced and full three-dimensional particle-in-cell simulations, show high energy efficiency, with about 10% of incident pulse energy transferred to 3 GeV electron bunches with sub-5% energy spread, half-nC charge, and absolutely no low-energy background. This optimal acceleration occurs in 2 cm length plasmas of electron density below 1018 cm-3. Due to their high charge and low phase space volume, these multi-GeV bunches are tailor-made for staged acceleration planned in the framework of the CILEX project. The hallmarks of the optimal regime are electron self-injection at the early stage of laser pulse propagation, stable self-guiding of the pulse through the entire acceleration process, and no need for an external plasma channel. With the initial focal spot closely matched for the nonlinear self-guiding, the laser pulse stabilizes transversely within two Rayleigh lengths, preventing subsequent evolution of the accelerating bucket. This dynamics prevents continuous self-injection of background electrons, preserving low phase space volume of the bunch through the plasma. Near the end of propagation, an optical shock builds up in the pulse tail. This neither disrupts pulse propagation nor produces any noticeable low-energy background in the electron spectra, which is in striking contrast with most of existing GeV-scale acceleration experiments.

  20. Experimental applications for the MARK-1 and MARK-1A pulsed ionizing radiation detection systems. Volume 3

    SciTech Connect

    Harker, Y.D.; Lawrence, R.S.; Yoon, W.Y.; Lones, J.L.

    1993-12-01

    This report is the third volume in a three volume set describing the MARK series of pulsed ionizing radiation detection systems. This volume describes the MARK-1A detection system, compares it with the MARK-1 system, and describes the experimental testing of the detection systems. Volume 1 of this set presents the technical specifications for the MARK-1 detection system. Volume 2 is an operations manual specifically for the MARK-1 system, but it generally applies to the MARK-1A system as well. These detection systems operate remotely and detect photon radiation from a single or a multiple pulsed source. They contain multiple detector (eight in the MARK-1 and ten in the MARK-1A) for determination of does and incident photon effective energy. The multiple detector arrangement, having different detector sizes and shield thicknesses, provides the capability of determining the effective photon energy of the radiation spectrum. Dose measurements using these units are consistent with TLD measurements. The detection range is from 3 nanorads to 90 microrads per source burst; the response is linear over that range. Three units were built and are ready for field deployment.

  1. Accelerated radiation damage test facility using a 5 MV tandem ion accelerator

    NASA Astrophysics Data System (ADS)

    Wady, P. T.; Draude, A.; Shubeita, S. M.; Smith, A. D.; Mason, N.; Pimblott, S. M.; Jimenez-Melero, E.

    2016-01-01

    We have developed a new irradiation facility that allows to perform accelerated damage tests of nuclear reactor materials at temperatures up to 400 °C using the intense proton (<100 μA) and heavy ion (≈10 μA) beams produced by a 5 MV tandem ion accelerator. The dedicated beam line for radiation damage studies comprises: (1) beam diagnosis and focusing optical components, (2) a scanning and slit system that allows uniform irradiation of a sample area of 0.5-6 cm2, and (3) a sample stage designed to be able to monitor in-situ the sample temperature, current deposited on the sample, and the gamma spectrum of potential radio-active nuclides produced during the sample irradiation. The beam line capabilities have been tested by irradiating a 20Cr-25Ni-Nb stabilised stainless steel with a 3 MeV proton beam to a dose level of 3 dpa. The irradiation temperature was 356 °C, with a maximum range in temperature values of ±6 °C within the first 24 h of continuous irradiation. The sample stage is connected to ground through an electrometer to measure accurately the charge deposited on the sample. The charge can be integrated in hardware during irradiation, and this methodology removes uncertainties due to fluctuations in beam current. The measured gamma spectrum allowed the identification of the main radioactive nuclides produced during the proton bombardment from the lifetimes and gamma emissions. This dedicated radiation damage beam line is hosted by the Dalton Cumbrian Facility of the University of Manchester.

  2. [A questionnaire about radiation safety management of the draining-water system at nuclear medicine facilities].

    PubMed

    Shizukuishi, Kazuya; Watanabe, Hiroshi; Narita, Hiroto; Kanaya, Shinichi; Kobayashi, Kazumi; Yamamoto, Tetsuo; Tsukada, Masaru; Iwanaga, Tetsuo; Ikebuchi, Shuji; Kusama, Keiji; Tanaka, Mamoru; Namiki, Norio; Fuiimura, Youko; Horikoshi, Akiko; Inoue, Tomio; Kusakabe, Kiyoko

    2004-05-01

    We conducted a questionnaire survey about radiation-safety management condition in Japanese nuclear medicine facilities to make materials of proposition for more reasonable management of medical radioactive waste. We distributed a questionnaire to institutions equipped with Nuclear Medicine facilities. Of 1,125 institutions, 642 institutes (52.8%) returned effective answers. The questionnaire covered the following areas: 1) scale of an institution, 2) presence of enforcement of radiotherapy, 3) system of a tank, 4) size and number of each tank, 5) a form of draining-water system, 6) a displacement in a radioactive rays management area, 7) a measurement method of the concentration of medical radioactive waste in draining water system, 8) planned and used quantity of radioisotopes for medical examination and treatment, 9) an average displacement of hospital for one month. In most institutions, a ratio of dose limitation of radioisotope in draining-water system was less than 1.0, defined as an upper limitation in ordinance. In 499 hospitals without facilities of hospitalization for unsealed radioisotope therapy, 473 hospitals reported that sum of ratios of dose limits in a draining-water system was less than 1.0. It was calculated by used dose of radioisotope and monthly displacement from hospital, on the premise that all used radioisotope entered in the general draining-water system. When a drainage including radioactivity from a controlled area join with that from other area before it flows out of a institution, it may be diluted and its radioactive concentration should be less than its upper limitation defined in the rule. Especially, in all institutions with a monthly displacement of more than 25,000 m3, the sum of ratio of the concentration of each radionuclide to the concentration limit dose calculated by used dose of radioisotope, indicated less than 1.0. PMID:15354724

  3. Efficient H/sub 2/ Raman conversion of long-pulse XeF laser radiation into blue-green region

    SciTech Connect

    Komine, H.; Stappaerts, E.A.; Brosnan, S.J.; West, J.B.

    1982-04-01

    Efficient Raman conversion of microsecond pulse XeF laser radiation into the blue-green region via the second Stokes shift in hydrogen has been demonstrated using a Raman oscillator-amplifier scheme. Strong depletion of the pump and the first Stokes radiation accompanied by a dominant second Stokes output was observed for the first time.

  4. Gravitational radiation as radiation same level of electromagnetic and its generation in pulsed high-current discharge. Theory and experiment.

    NASA Astrophysics Data System (ADS)

    Fisenko, Stanislav; Fisenko, Igor

    2015-04-01

    The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is based on theoretically proved and experimentally confirmed fact of existence of stationary states of an electron in its gravitational field characterized by the gravitational constant K = 1042 G (G is the Newtonian gravitational constant) and unrecoverable space-time curvature Λ. This paper gives an overview of the authors' works, which set out the relevant results. Additionally, data is provided on the broadening of the spectra characteristic radiation. The data show that this broadening can be explained only by the presence of excited states of electrons in their gravitational field. What is more, the interpretation of the new line of X-ray emission spectrum according to the results of observation of MOS-camera of XMM-Newton observatory is of interest. The given work contributes into further elaboration of the findings considering their application to dense high-temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational radiation spectrum such that amplification of gravitational radiation may take place only in multiple-charge ion high-temperature plasma.

  5. Radiation protection in fixed PET/CT facilities--design and operation.

    PubMed

    Peet, D J; Morton, R; Hussein, M; Alsafi, K; Spyrou, N

    2012-05-01

    We describe the design of a fixed positron emission tomography (PET)/CT facility and the use of a simulated instantaneous dose-rate plot to visually highlight areas of potentially high radiation exposure. We also illustrate the practical implementation of basic radiation protection principles based on the use of distance and shielding and the minimisation of time spent in hot areas. Staff whole body doses for 4 years are presented with results of an optimisation study analysing the dose arising from the different phases within each study using direct reading dosemeters. The total whole body dose for all staff for each patient fell from 9.5 μSv in the first full year of operation to 4.8 µSv in 2008. The maximum dose to an individual member of staff per patient decreased over the same period from 3.2 to 0.9 µSv. The optimisation study showed that the highest dose was recorded during the injection phase. PMID:21976626

  6. The High Energy cosmic-Radiation Detection (HERD) Facility onboard China's Future Space Station

    NASA Astrophysics Data System (ADS)

    Wu, Bobing

    2015-08-01

    The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs)from five sides except the bottom. CALO is made of about 10^4 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; 2) electron/proton separation power better than 10^5 ; effective geometrical factors of > 3 m^2 sr for electron and diffuse gamma-rays, > 2 m^2 sr for cosmic ray nuclei. The prototype of about 1/40 of HERD calorimeter is under construction. A beam test in CERN with the prototype is approved and will be carried out in Nov. 2015.

  7. Radiation impact caused by activation of air from the future GSI accelerator facility fair.

    PubMed

    Gutermuth, F; Wildermuth, H; Radon, T; Fehrenbacher, G

    2005-01-01

    The Gesellschaft für Schwerionenforschung in Darmstadt is planning a new accelerator Facility for Antiproton and Ion Research (FAIR). Two future experimental areas are regarded to be the most decisive points concerning the activation of air. One is the area for the production of antiprotons. A second crucial experimental area is the so-called Super Fragment Separator. The production of radioactive isotopes in air is calculated using the residual nuclei option of the Monte Carlo program FLUKA. The results are compared with the data for the activation of air given by Sullivan and in IAEA report 283. The resulting effective dose is calculated using a program package from the German Federal Office for Radiation Protection, the Bundesamt für Stranlenschutz. The results demonstrate that a direct emission of the total radioactivity produced into the air will probably conflict with the limits of the German Radiation Protection Ordinance. Special measures have to be planned in order to reduce the amount of radioactivity released into the air. PMID:16381762

  8. The Shock/Shear platform for planar radiation-hydrodynamics experiments on the National Ignition Facility

    SciTech Connect

    Doss, F. W. Kline, J. L.; Flippo, K. A.; Perry, T. S.; DeVolder, B. G.; Tregillis, I.; Loomis, E. N.; Merritt, E. C.; Murphy, T. J.; Welser-Sherrill, L.; Fincke, J. R.

    2015-05-15

    An indirectly-driven shock tube experiment fielded on the National Ignition Facility (NIF) was used to create a high-energy-density hydrodynamics platform at unprecedented scale. Scaling up a shear-induced mixing experiment previously fielded at OMEGA, the NIF shear platform drives 130 μm/ns shocks into a CH foam-filled shock tube (∼ 60 mg/cc) with interior dimensions of 1.5 mm diameter and 5 mm length. The pulse-shaping capabilities of the NIF are used to extend the drive for >10 ns, and the large interior tube volumes are used to isolate physics-altering edge effects from the region of interest. The scaling of the experiment to the NIF allows for considerable improvement in maximum driving time of hydrodynamics, in fidelity of physics under examination, and in diagnostic clarity. Details of the experimental platform and post-shot simulations used in the analysis of the platform-qualifying data are presented. Hydrodynamic scaling is used to compare shear data from OMEGA with that from NIF, suggesting a possible change in the dimensionality of the instability at late times from one platform to the other.

  9. The shock/shear platform for planar radiation-hydrodynamics experiments on the National Ignition Facility

    SciTech Connect

    Doss, F. W.; Kline, J. L.; Flippo, K. A.; Perry, T. S.; DeVolder, B. G.; Tregillis, I.; Loomis, E. N.; Merritt, E. C.; Murphy, T. J.; Welser-Sherrill, L.; Fincke, J. R.

    2015-04-17

    An indirectly-driven shock tube experiment fielded on the National Ignition Facility (NIF) was used to create a high-energy-density hydrodynamics platform at unprecedented scale. Scaling up a shear-induced mixing experiment previously fielded at OMEGA, the NIF shear platform drives 130 μm/ns shocks into a CH foam-filled shock tube (~ 60 mg/cc) with interior dimensions of 1.5 mm diameter and 5 mm length. The pulse-shaping capabilities of the NIF are used to extend the drive for >10 ns, and the large interior tube volumes are used to isolate physics-altering edge effects from the region of interest. The scaling of the experiment to the NIF allows for considerable improvement in maximum driving time of hydrodynamics, in fidelity of physics under examination, and in diagnostic clarity. Details of the experimental platform and post-shot simulations used in the analysis of the platform-qualifying data are presented. Hydrodynamic scaling is used to compare shear data from OMEGA with that from NIF, suggesting a possible change in the dimensionality of the instability at late times from one platform to the other.

  10. The shock/shear platform for planar radiation-hydrodynamics experiments on the National Ignition Facility

    DOE PAGESBeta

    Doss, F. W.; Kline, J. L.; Flippo, K. A.; Perry, T. S.; DeVolder, B. G.; Tregillis, I.; Loomis, E. N.; Merritt, E. C.; Murphy, T. J.; Welser-Sherrill, L.; et al

    2015-04-17

    An indirectly-driven shock tube experiment fielded on the National Ignition Facility (NIF) was used to create a high-energy-density hydrodynamics platform at unprecedented scale. Scaling up a shear-induced mixing experiment previously fielded at OMEGA, the NIF shear platform drives 130 μm/ns shocks into a CH foam-filled shock tube (~ 60 mg/cc) with interior dimensions of 1.5 mm diameter and 5 mm length. The pulse-shaping capabilities of the NIF are used to extend the drive for >10 ns, and the large interior tube volumes are used to isolate physics-altering edge effects from the region of interest. The scaling of the experiment tomore » the NIF allows for considerable improvement in maximum driving time of hydrodynamics, in fidelity of physics under examination, and in diagnostic clarity. Details of the experimental platform and post-shot simulations used in the analysis of the platform-qualifying data are presented. Hydrodynamic scaling is used to compare shear data from OMEGA with that from NIF, suggesting a possible change in the dimensionality of the instability at late times from one platform to the other.« less

  11. Assessment of radiation exposure for materials in the LANSCE Spallation Irradiation Facility

    SciTech Connect

    James, M. R.; Maloy, S. A.; Sommer, W. F. , Jr.; Fowler, Malcolm M.; Dry, D. E.; Ferguson, P. D.; Corzine, R. K.; Mueller, G. E.

    2001-01-01

    Materials samples were irradiated in the Los Alamos Radiation Effects Facility (LASREF) at the Los Alamos Neutron Science Center (LANSCE) to provide data for the Accelerator Production of Tritium (APT) project on the changes in mechanical and physical properties of materials in a spallation target environment. The targets were configured to expose samples to a variety of radiation environments including high-energy protons, mixed protons and neutrons, and predominantly neutrons. The irradiation was driven by an 800 MeV 1 mA proton beam with a circular Gaussian shape of approximately 2{sigma} = 3.5 cm. Two irradiation campaigns were conducted in which samples were exposed for approximately six months and two months, respectively. At the end of this period, the samples were extracted and tested. Activation foils that had been placed in proximity to the materials samples were used to quantify the fluences in various locations. The STAYSL2 code was used to estimate the fluences by combining the activation foil data with calculated data from the LAHET Code System (LCS) and MCNPX. The exposure for each sample was determined from the estimated fluences using interpolation based on a mathematical fitting to the fluence results. The final results included displacement damage (dpa) and gas (H, He) production for each sample from the irradiation. Based on the activation foil analysis, samples from several locations in both irradiation campaigns were characterized. The radiation damage to each sample was highly dependent upon location and varied from 0.023 to 13 dpa and was accompanied by high levels of H and He production.

  12. A new facility for the synchrotron radiation-based calibration of transfer radiation sources in the ultraviolet and vacuum ultraviolet spectral range

    SciTech Connect

    Thornagel, Reiner; Fliegauf, Rolf; Klein, Roman Kroth, Simone; Paustian, Wolfgang; Richter, Mathias

    2015-01-15

    The Physikalisch-Technische Bundesanstalt (PTB) has a long tradition in the calibration of radiation sources in the ultraviolet and vacuum ultraviolet spectral range, with traceability to calculable synchrotron radiation. Within this context, new instrumentation in the PTB laboratory at the Metrology Light Source (MLS) has been put into operation that opens up extended and improved calibration possibilities. A new facility for radiation source calibrations has been set up in the spectral range from 7 nm to 400 nm based on a combined normal incidence-grazing incidence monochromator. The facility can be used for the calibration of transfer sources in terms of spectral radiant intensity or mean spectral radiance, with traceability to the MLS primary source standard. We describe the design and performance of the experimental station and give examples of some commissioning results.

  13. A new facility for the synchrotron radiation-based calibration of transfer radiation sources in the ultraviolet and vacuum ultraviolet spectral range

    NASA Astrophysics Data System (ADS)

    Thornagel, Reiner; Fliegauf, Rolf; Klein, Roman; Kroth, Simone; Paustian, Wolfgang; Richter, Mathias

    2015-01-01

    The Physikalisch-Technische Bundesanstalt (PTB) has a long tradition in the calibration of radiation sources in the ultraviolet and vacuum ultraviolet spectral range, with traceability to calculable synchrotron radiation. Within this context, new instrumentation in the PTB laboratory at the Metrology Light Source (MLS) has been put into operation that opens up extended and improved calibration possibilities. A new facility for radiation source calibrations has been set up in the spectral range from 7 nm to 400 nm based on a combined normal incidence-grazing incidence monochromator. The facility can be used for the calibration of transfer sources in terms of spectral radiant intensity or mean spectral radiance, with traceability to the MLS primary source standard. We describe the design and performance of the experimental station and give examples of some commissioning results.

  14. Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2006.

    SciTech Connect

    Sisterson, D. L.

    2007-03-14

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), the actual hours of operation, and the variance (unplanned downtime) for the period October 1 through December 31, 2006, for the fixed and mobile sites. Although the AMF is currently up and running in Niamey, Niger, Africa, the AMF statistics are reported separately and not included in the aggregate average with the fixed sites. The first quarter comprises a total of 2,208 hours. For all fixed sites, the actual data availability (and therefore actual hours of operation) exceeded the individual (and well as aggregate average of the fixed sites) operational goal for the first quarter of fiscal year (FY) 2007. The Site Access Request System is a web-based database used to track visitors to the fixed sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a Central Facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. NIM represents the AMF statistics for the current deployment in Niamey, Niger, Africa. PYE represents the AMF statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be

  15. Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2008.

    SciTech Connect

    Sisterson, D. L.

    2009-01-15

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, they calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The US Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 x 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is

  16. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2008

    SciTech Connect

    Sisterson, DL

    2008-09-30

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the fourth quarter of FY 2008 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 x 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is

  17. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2005

    SciTech Connect

    Sisterson, DL

    2005-12-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,097.6 hours (0.95 × 2,208 hours this quarter). The OPSMAX for the North Slope of Alaska (NSA) locale is 1,987.2 hours (0.90 × 2,208), and that for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 × 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,097.6 hours (0.95 × 2,208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent

  18. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January-March 2006

    SciTech Connect

    Sisterson, DL

    2006-03-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year; and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the second quarter for the Southern Great Plains (SGP) site is 2,052 hours (0.95 × 2,160 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,944 hours (0.90 × 2,160), and that for the Tropical Western Pacific (TWP) locale is 1,836 hours (0.85 × 2,160). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,052 hours (0.95 × 2,160). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the

  19. Implementing storage rings free electron lasers for users on synchrotron radiation facilities: from Super-ACO to SOLEIL

    NASA Astrophysics Data System (ADS)

    Couprie, M. E.; Nutarelli, D.; Billardon, M.

    1998-09-01

    Storage Ring Free Electron Laser (SRFEL) sources can be implemented on synchrotron radiation facilities. Although in the beginning an additional experiment on the accelerator requires specific operating conditions as on Super-ACO at Orsay (France), they can now be conceived as an integral part of the project, providing coherent picosecond tunable light in the UV-VUV range, synchronized with synchrotron radiation for the scientific community, as on the SOLEIL project. Third generation storage ring beam characteristics are discussed in terms of synchrotron radiation and FEL optimization. FEL performances are presented, showing the improvement between the Super-ACO and the SOLEIL cases, including stability issues.

  20. Making good use of synchrotron radiation, The role of CHESS at Cornell and as a national facility

    SciTech Connect

    Batterman, B.W.

    1986-01-01

    Atom smashers is what the New York Times calls them when it publishes a piece about particle accelerators. Historically, particle accelerators were in fact used to break apart atoms, but modern machines do more exotic things. One of them is a spin-off of acceleration - the production of high-energy synchrotron radiation. Once considered a nuisance, this radiation has become valuable in almost every field of science and engineering. It is the basis of a national facility, the Cornell High Energy Synchrotron Source (CHESS), that operates in conjunction with the Cornell Electron Storage Ring (CESR). CHESS provides the highest-energy synchrotron radiation available in the United States.

  1. Reduction of wavefront aberrations and laser radiation divergence of the 'Luch' facility with the help of an adaptive system

    SciTech Connect

    Voronich, Ivan N; Garanin, Sergey G; Zaretskii, Aleksei I; Zimalin, B G; Kirillov, G A; Kulikov, S M; Manachinckii, A N; Murugov, Vasilii M; Ogorodnikov, A V; Smyshlyaev, S P; Sukharev, Stanislav A

    2005-02-28

    An adaptive system for the compensation of static and thermally induced wavefront aberrations of the amplification path of the 'Luch' laser facility is described. This system provided the reduction of the amplitude A of wavefront aberrations of high-power radiation and the standard deviation {sigma} by a factor of {approx}3: from A = 9.6 {mu}m, {sigma} = 2.4 {mu}m to A = 3.2 {mu}m, {sigma} = 0.6 {mu}m, which decreased the radiation divergence by half. (control of laser radiation parameters)

  2. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra.

    PubMed

    Engel, Robin; Düsterer, Stefan; Brenner, Günter; Teubner, Ulrich

    2016-01-01

    For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH's data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded. PMID:26698053

  3. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra

    PubMed Central

    Engel, Robin; Düsterer, Stefan; Brenner, Günter; Teubner, Ulrich

    2016-01-01

    For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH’s data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded. PMID:26698053

  4. Radiation-induced pink nickel oligomeric clusters in water. Pulse radiolysis study.

    PubMed

    Hioul, Mohamed Larbi; Lin, Mingzhang; Belloni, Jacqueline; Keghouche, Nassira; Marignier, Jean-Louis

    2014-10-01

    γ-rays and pulse radiolysis of aqueous solutions of Ni(2+) ions in the presence of polyacrylate (PA(-)) and 2-propanol leads to the formation of metastable species absorbing at 540 nm that are ascribed to "pink" oligomeric clusters of a few nickel atoms only. The molar absorption coefficient is evaluated as ε540 nm = 3300 ± 300 L mol(-1) cm(-1) per Ni(0) atom. The successive steps from the reduction of Ni(2+) into Ni(+) ions to the formation of the pink clusters at 540 nm under conditions of complexation by PA(-) are investigated by pulse radiolysis. The yield of the formation of pink clusters increases markedly with the irradiation dose rate, demonstrating the occurrence of the disproportionation of the [Ni(+), PA(-)] complex after a single electron pulse. The reduction and nucleation mechanisms, including rate constants, in competition with the back oxidation by protons, particularly at low dose rate, are discussed. PMID:25198291

  5. Atmospheric Radiation Measurement program climate research facility operations quarterly report January 1 - March 31, 2008.

    SciTech Connect

    Sisterson, D. L.

    2008-05-22

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period January 1 - March 31, 2008, for the fixed sites. The AMF is being deployed to China and is not in operation this quarter. The second quarter comprises a total of 2,184 hours. The average as well as the individual site values exceeded our goal this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. FKB represents the AMF statistics for the Haselbach, Germany, past deployment in 2007. NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request a research account on the local site data system. The seven computers for the research accounts are located at the Barrow

  6. Atmospheric Radiation Measurement program climate research facility operations quarterly report July 1 - September 30, 2008.

    SciTech Connect

    Sisterson, D. L.

    2008-10-08

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period July 1 - September 30, 2008, for the fixed sites. The AMF has been deployed to China, but the data have not yet been released. The fourth quarter comprises a total of 2,208 hours. The average exceeded our goal this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. HFE represents the AMF statistics for the Shouxian, China, deployment in 2008. FKB represents the AMF statistics for the Haselbach, Germany, past deployment in 2007. NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request a research account on the local site data system. The seven computers for the

  7. Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2007.

    SciTech Connect

    Sisterson, D. L.

    2008-01-24

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period October 1 - December 31, 2007, for the fixed sites and the mobile site. The AMF has been deployed to Germany and this was the final operational quarter. The first quarter comprises a total of 2,208 hours. Although the average exceeded our goal this quarter, a series of severe weather events (i.e., widespread ice storms) disrupted utility services, which affected the SGP performance measures. Some instruments were covered in ice and power and data communication lines were down for more than 10 days in some areas of Oklahoma and Kansas, which resulted in lost data at the SGP site. The Site Access Request System is a web-based database used to track visitors to the fixed sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. The AMF completed its mission at the end of this quarter in Haselback, Germany (FKB designation). NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE

  8. Occupational radiation exposure at commercial nuclear power reactors and other facilities 1992; Twenty-fifth annual report, Volume 14

    SciTech Connect

    Raddatz, C.T.; Hagemeyer, D.

    1993-12-01

    This report summarizes the occupational radiation exposure information that has been reported to the NRC`s Radiation Exposure Information Reporting System (REIRS) by nuclear power facilities and certain other categories of NRC licensees during the years 1969 through 1992. The bulk of the data presented in the report was obtained from annual radiation exposure reports submitted in accordance with the requirements of 10CFR20.407 and the technical specifications of nuclear power plants. Data on workers terminating their employment at certain NRC licensed facilities were obtained from reports submitted pursuant to 10CFR20.408. The 1992 annual reports submitted by about 364 licensees indicated that approximately 204,365 individuals were monitored, 183,927 of whom were monitored by nuclear power facilities. They incurred an average individual dose of 0.16 rem (cSv) and an average measurable dose of about 0.30 (cSv). Termination radiation exposure reports were analyzed to reveal that about 74,566 individuals completed their employment with one or more of the 364 covered licensees during 1992. Some 71,846 of these individuals terminated from power reactor facilities, and about 9,724 of them were considered to be transient workers who received an average dose of 0.50 rem (cSv).

  9. SBS of repetitively pulsed radiation and possibility of increasing of the pump average power

    SciTech Connect

    Andreev, N.; Kulagin, O.; Palashov, O.; Pasmanik, G.; Rodchenkov, V.

    1995-12-31

    The features of liquid purification from molecular and dispersive admixtures are studied. The analysis has revealed the processes (thermal effects, microparticles heating with a subsequent optical breakdown, Stimulated Raman Scattering) limiting pumping pulse energy. These effects complicate also a realization of a high quality phase conjugation at SBS. The data concerning physical properties of liquid tetrachlorides and freons are presented. The picture of a behavior of liquid under conditions of an optical breakdown is described. Some recommendations regarding a choice of nonlinear media are formulated. The two-cell scheme providing a phase conjugation of powerful short laser pulses is proposed. This is important in the field of inertial confinement fusion.

  10. Optical control of electron trapping: Generation of comb-like electron beams for tunable, pulsed, multi-color radiation sources

    NASA Astrophysics Data System (ADS)

    Kalmykov, Serge

    2014-10-01

    All-optical control over the electron phase space in laser-plasma accelerators enables production of ``designer'' electron beams that can be optimized for specific applications. GeV-scale acceleration with sub-100 TW (rather than PW) laser pulses, at repetition rates orders-of-magnitude higher than permitted by existing PW facilities, in a few-mm (rather than cm) length plasmas, requires maintaining an accelerating gradient as high as 10 GV/cm. This, in turn, dictates acceleration in the blowout regime in a dense plasma (~1019 cm-3). These highly dispersive plasmas rapidly transform the drive pulse into a relativistic optical shock, causing the plasma wake bucket (electron density bubble) to constantly expand, trapping background electrons, greatly degrading beam quality. We show that these effects can be overcome using a high-bandwidth driver (over 1/2 the carrier frequency) with a negative frequency chirp. Temporally advancing higher frequencies (thus compensating for the plasma-induced nonlinear frequency red-shift) and propagating the pulse in a plasma channel (to suppress diffraction of its leading edge) delays pulse self-steepening through electron dephasing and extends the dephasing length. As a result, continuous injection is suppressed and electron energy is boosted to the GeV level. In addition, periodic self-injection in the channel produces a sequence of femtosecond-length, quasi-monoenergetic bunches. The number of these spectral components, their charge, energy, and energy separation can be controlled by varying the channel radius and length, whereas accumulation of the noise (viz. continuously injected charge) is prevented by the negative chirp of the driver. This level of control is hard to achieve with conventional accelerator techniques. It is demonstrated that these clean, polychromatic, comb-like beams can drive high-brightness, tunable, multi-color gamma-ray sources. Work is supported by the US DOE Grant DE-SC0008382 and NSF Grant PHY-1104683.

  11. 76 FR 37798 - DOE Response to Recommendation 2010-2 of the Defense Nuclear Facilities Safety Board, Pulse Jet...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... Waste Treatment and Immobilization Plant AGENCY: Department of Energy. ACTION: Notice. SUMMARY: On May..., concerning Pulse Jet Mixing at the Waste Treatment and Immobilization Plant, to the Department of Energy. In... Safety Board (Board) Recommendation 2010-2, Pulse Jet Mixing (PJM) at the Waste Treatment...

  12. The association betweeen cancers and low level radiation: An evaluation of the epidemiological evidence at the Hanford Nuclear Weapons Facility

    SciTech Connect

    Britton, J. |

    1993-05-01

    Cancer has traditionally been linked to exposure to high doses of radiation, but there is considerable controversy regarding the carcinogenicity of low doses of ionizing radiation in humans. Over the past 30 years there have been 14 studies conducted on employees at the Hanford nuclear weapons facility to investigate the relationship between exposure to low doses of radiation and mortality due to cancer (1-14). Interest in this issue was originally stimulated by the Atomic Energy Commission (AEC) which was trying to determine whether the linear extrapolation of health effects from high to low dose exposure was accurate. If the risk has been underestimated, then the maximum permissible occupational radiation exposure in the United States had been set too high. Because the health risk associated with low level radiation are unclear and controversial it seems appropriate to review the studies relating to Hanford at this time.

  13. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress.

    PubMed

    Schooneveld, E M; Pietropaolo, A; Andreani, C; Perelli Cippo, E; Rhodes, N J; Senesi, R; Tardocchi, M; Gorini, G

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources. PMID:27502571

  14. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    NASA Astrophysics Data System (ADS)

    Schooneveld, E. M.; Pietropaolo, A.; Andreani, C.; Perelli Cippo, E.; Rhodes, N. J.; Senesi, R.; Tardocchi, M.; Gorini, G.

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  15. The electromagnetic radiation fields of a relativistic electron avalanche with special attention to the origin of narrow bipolar pulses

    NASA Astrophysics Data System (ADS)

    Cooray, G. V.; Cooray, G. K.

    2011-12-01

    Gurevich et al. [1] postulated that the source of narrow bipolar pulses, a class of high energy pulses that occur during thunderstorms, could be a runaway electron avalanche driven by the intense electric fields of a thunderstorm. Recently, Watson and Marshall [2] used the modified transmission line model to test the mechanism of the source of narrow bipolar pulses. In a recent paper, Cooray and Cooray [3] demonstrated that the electromagnetic fields of accelerating charges could be used to evaluate the electromagnetic fields from electrical discharges if the temporal and spatial variation of the charges in the discharge is known. In the present study, those equations were utilized to evaluate the electromagnetic fields generated by a relativistic electron avalanche. In the analysis it is assumed that all the electrons in the avalanche are moving with the same speed. In other words, the growth or the decay of the number of electrons takes place only at the head of the avalanche. It is shown that the radiation is emanating only from the head of the avalanche where electrons are being accelerated. It is also shown that an analytical expression for the radiation field of the avalanche at any distance can be written directly in terms of the e-folding length of the avalanche. This makes it possible to extract directly the spatial variation of the e-folding length of the avalanche from the measured radiation fields. In the study this model avalanche was used to investigate whether it can be used to describe the measured electromagnetic fields of narrow bipolar pulses. The results obtained are in reasonable agreement with the two station data of Eack [4] for speeds of propagation around (2 - 2.5) x 10^8 m/s and when the propagation effects on the electric fields measured at the distant station is taken into account. [1] Gurevich et al. (2004), Phys. Lett. A., 329, pp. 348 -361. [2] Watson, S. S. and T. C. Marshall (2007), Geophys. Res. Lett., Vol. 34, L04816, doi: 10

  16. Performances of single and two-stage pulse tube cryocoolers under different vacuum levels with and without thermal radiation shields

    NASA Astrophysics Data System (ADS)

    Kasthurirengan, Srinivasan; Behera, Upendra; Nadig, D. S.; Krishnamoorthy, V.

    2012-06-01

    Single and two-stage Pulse Tube Cryocoolers (PTC) have been designed, fabricated and experimentally studied. The single stage PTC reaches a no-load temperature of ~ 29 K at its cold end, the two-stage PTC reaches ~ 2.9 K in its second stage cold end and ~ 60 K in its first stage cold end. The two-stage Pulse Tube Cryocooler provides a cooling power of ~ 250 mW at 4.2 K. The single stage system uses stainless steel meshes along with Pb granules as its regenerator materials, while the two-stage PTC uses combinations of Pb along with Er3Ni / HoCu2 as the second stage regenerator materials. Normally, the above systems are insulated by thermal radiation shields and mounted inside a vacuum chamber which is maintained at high vacuum. To evaluate the performance of these systems in the possible conditions of loss of vacuum with and without radiation shields, experimental studies have been performed. The heat-in-leak under such severe conditions has been estimated from the heat load characteristics of the respective stages. The experimental results are analyzed to obtain surface emissivities and effective thermal conductivities as a function of interspace pressure.

  17. Investigation of pulsed X-ray radiation of a plasma focus in a broad energy range

    SciTech Connect

    Savelov, A. S. Salakhutdinov, G. Kh.; Koltunov, M. V.; Lemeshko, B. D.; Yurkov, D. I.; Sidorov, P. P.

    2011-12-15

    The results of the experimental investigations of the spectral composition of plasma focus X-ray radiation in the photon energy range of 1.5 keV-400 keV are presented. Three regions in the radiation spectrum where the latter is of a quasi-thermal nature with a corresponding effective temperature are distinguished.

  18. Ultrafast spin switching in a canted antiferromagnetic YFeO3 driven by pulsed THz radiations

    NASA Astrophysics Data System (ADS)

    Kim, Taeheon; Hamh, Sun Young; Han, Jeong Woo; Kang, Chul; Kee, Chul-Sik; Jung, Seonghoon; Park, Jaehun; Tokunaga, Yusuke; Tokura, Yoshinori; Lee, Jong Seok

    2015-03-01

    We investigate a detailed process of the precessional motion of the magnetic moment in the canted antiferromagnetic YFeO3 which is excited by a linearly polarized terahertz (THz) pulse at room temperature. By tuning the spectral component of the input THz pulse around the quasi-ferromagnetic mode located near 0.3 THz, we have experimentally clarified the resonance effect in the THz control of the spin state. We could confirm this result also from the simulation based on the Landau-Lifshitz-Gilbert equation with two sub-lattice model for the canted antiferromagnet. Furthermore, we demonstrate that the spin state can be switched all-optically on a picosecond time-scale using THz pulses of square and oscillating shapes. Whereas the oscillating THz pulse with a spectral component resonant with the magnetic excitations is necessary for an efficient magnetization switching, we check the possibility of a further reduction of the necessary THz field strength by examining influences of variations in the anisotropy energy and Dzyaloshinskii-Moriya interaction upon the switching behaviors.

  19. Investigation of thermal distribution for pulsed laser radiation in cancer treatment with nanoparticle-mediated hyperthermia.

    PubMed

    Sazgarnia, Ameneh; Naghavi, Nadia; Mehdizadeh, Hoda; Shahamat, Zahra

    2015-01-01

    In this paper, we have simulated the efficacy of gold/gold sulfide (GGS) nanoshells in NIR laser hyperthermia to achieve effective targeting for tumor photothermal therapy. The problem statement takes into account the heat transfer with the blood perfusion through capillaries, and pulsed laser irradiation during the hyperthermia. Although previous researchers have used short laser pulses (nanosecond and less), in order to prevent heat leakage to the neighbor tissues, we have examined the effect of millisecond pulses, as the extent of the target volume to which hyperthermia is induced is usually larger and also the lasers with this specification are more available. A tumor with surrounding tissue was simulated in COMSOL software (a finite element analysis, solver and simulation software) and also in a phantom made of agarose and intralipid. The tumor was irradiated by 10, 20 and 30 laser pulses with durations of 15, 50 and 200ms and fluences of 20, 40 and 60J/cm(2). Experimental tests performed on a phantom prove the ability of the applied numerical model to capture the temperature distribution in the target tissue. We have shown that our simulation permits prediction of treatment outcome from computation of thermal distribution within the tumor during laser hyperthermia using GGS nanoshells and millisecond pulsed laser irradiation. The advantage of this simulation is its simplicity as well as its accuracy. Although, to develop the model completely for a given organ and application, all the parameters should be estimated based on a real vasculature of the organ, physiological conditions, and expected variation in those physiological conditions for that application in the organ. PMID:25526652

  20. Radiative shocks produced from spherical cryogenic implosions at the National Ignition Facility

    SciTech Connect

    Pak, A.; Divol, L.; Weber, S.; Atherton, J.; Bennedetti, R.; Bradley, D. K.; Callahan, D.; Casey, D. T.; Dewald, E.; Döppner, T.; Edwards, M. J.; Glenn, S.; Hicks, D.; Hsing, W. W.; Izumi, N.; Jones, O. S.; Khan, S. F.; Lindl, J.; Landen, O. L.; Le Pape, S.; and others

    2013-05-15

    Spherically expanding radiative shock waves have been observed from inertially confined implosion experiments at the National Ignition Facility. In these experiments, a spherical fusion target, initially 2 mm in diameter, is compressed via the pressure induced from the ablation of the outer target surface. At the peak compression of the capsule, x-ray and nuclear diagnostics indicate the formation of a central core, with a radius and ion temperature of ∼20 μm and ∼ 2 keV, respectively. This central core is surrounded by a cooler compressed shell of deuterium-tritium fuel that has an outer radius of ∼40 μm and a density of >500 g/cm{sup 3}. Using inputs from multiple diagnostics, the peak pressure of the compressed core has been inferred to be of order 100 Gbar for the implosions discussed here. The shock front, initially located at the interface between the high pressure compressed fuel shell and surrounding in-falling low pressure ablator plasma, begins to propagate outwards after peak compression has been reached. Approximately 200 ps after peak compression, a ring of x-ray emission created by the limb-brightening of a spherical shell of shock-heated matter is observed to appear at a radius of ∼100 μm. Hydrodynamic simulations, which model the experiment and include radiation transport, indicate that the sudden appearance of this emission occurs as the post-shock material temperature increases and upstream density decreases, over a scale length of ∼10 μm, as the shock propagates into the lower density (∼1 g/cc), hot (∼250 eV) plasma that exists at the ablation front. The expansion of the shock-heated matter is temporally and spatially resolved and indicates a shock expansion velocity of ∼300 km/s in the laboratory frame. The magnitude and temporal evolution of the luminosity produced from the shock-heated matter was measured at photon energies between 5.9 and 12.4 keV. The observed radial shock expansion, as well as the magnitude and temporal

  1. A Midlatitude Cirrus Cloud Climatology from the Facility for Atmospheric Remote Sensing. Part III: Radiative Properties

    SciTech Connect

    Sassen, K.; Comstock, Jennifer M.

    2001-08-01

    In Part III of a series of papers describing the extended time high-cloud observations from the University of Utah Facility for Atmospheric Remote Sensing (FARS) supporting the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment, the visible and infrared radiative properties of cirrus clouds over Salt Lake City, Utah, are examined. Using {approx}860 h of combined ruby (0.694 {micro}m) lidar and midinfrared (9.5-11.5 {micro}m) radiometer data collected between 1992 and 1999 from visually identified cirrus clouds, the visible optical depths {tau} and infrared layer emittance epsilon of the varieties of midlatitude cirrus are characterized. The mean and median values for the cirrus sample are 0.75 {+-} 0.91 and 0.61 for {tau}, and 0.30 {+-} 0.22 and 0.25 for epsilon. Other scattering parameters studied are the visible extinction and infrared absorption coefficients, and their ratio, and the lidar backscatter-to-extinction ratio, which has a mean value of 0.041 sr{sup -1}. Differences among cirrus clouds generated by general synoptic (e.g., jet stream), thunderstorm anvil, and orographic mechanisms are found, reflecting basic cloud microphysical effects. The authors draw parameterizations in terms of midcloud temperature T{sub m} and physical cloud thickness {Delta}z for epsilon and {tau}: both macrophysical variables are needed to adequately address the impact of the adiabatic process on ice cloud content, which modulates radiative transfer as a function of temperature. For the total cirrus dataset, the authors find epsilon = 1 -exp [-8.5 x 10{sup -5} (T{sub m} + 80 C) {Delta}z]. These parameterizations, based on a uniquely comprehensive dataset, hold the potential for improving weather and climate model predictions, and satellite cloud property retrieval methods.

  2. The high energy cosmic-radiation detection (HERD) facility onboard China's Space Station

    NASA Astrophysics Data System (ADS)

    Zhang, S. N.; Adriani, O.; Albergo, S.; Ambrosi, G.; An, Q.; Bao, T. W.; Battiston, R.; Bi, X. J.; Cao, Z.; Chai, J. Y.; Chang, J.; Chen, G. M.; Chen, Y.; Cui, X. H.; Dai, Z. G.; D'Alessandro, R.; Dong, Y. W.; Fan, Y. Z.; Feng, C. Q.; Feng, H.; Feng, Z. Y.; Gao, X. H.; Gargano, F.; Giglietto, N.; Gou, Q. B.; Guo, Y. Q.; Hu, B. L.; Hu, H. B.; He, H. H.; Huang, G. S.; Huang, J.; Huang, Y. F.; Li, H.; Li, L.; Li, Y. G.; Li, Z.; Liang, E. W.; Liu, H.; Liu, J. B.; Liu, J. T.; Liu, S. B.; Liu, S. M.; Liu, X.; Lu, J. G.; Mazziotta, M. N.; Mori, N.; Orsi, S.; Pearce, M.; Pohl, M.; Quan, Z.; Ryde, F.; Shi, H. L.; Spillantini, P.; Su, M.; Sun, J. C.; Sun, X. L.; Tang, Z. C.; Walter, R.; Wang, J. C.; Wang, J. M.; Wang, L.; Wang, R. J.; Wang, X. L.; Wang, X. Y.; Wang, Z. G.; Wei, D. M.; Wu, B. B.; Wu, J.; Wu, X.; Wu, X. F.; Xia, J. Q.; Xiao, H. L.; Xu, H. H.; Xu, M.; Xu, Z. Z.; Yan, H. R.; Yin, P. F.; Yu, Y. W.; Yuan, Q.; Zha, M.; Zhang, L.; Zhang, L.; Zhang, L. Y.; Zhang, Y.; Zhang, Y. J.; Zhang, Y. L.; Zhao, Z. G.

    2014-07-01

    The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 104 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R and D is under way for reading out the LYSO signals with optical fiber coupled to image intensified CCD and the prototype of one layer of CALO.

  3. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2005

    SciTech Connect

    Sisterson, DL

    2005-03-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for this second quarter for the Southern Great Plains (SGP) site is 2052 hours (0.95 × 2,160 hours this quarter). The annual OPSMAX for the North Slope Alaska (NSA) site is 1944 hours (0.90 × 2,160), and that for the Tropical Western Pacific (TWP) site is 1836 hours (0.85 × 2,160). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 90

  4. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2004

    SciTech Connect

    Sisterson, DL

    2004-12-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The annual OPSMAX time for the Southern Great Plains (SGP) site is 8,322 hours per year (0.95 × 8,760, the number hours in a year, not including leap year). The annual OPSMAX for the North Slope Alaska (NSA) site is 7,884 hours per year (0.90 × 8,760), and that for the Tropical Western Pacific (TWP) site is 7,446 hours per year (0.85 × 8,760). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the

  5. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report. October 1 - December 31, 2010.

    SciTech Connect

    Sisterson, D. L.

    2011-02-01

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near-real time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY2010 for the Southern Great Plains (SGP) site is 2097.60 hours (0.95 x 2208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1987.20 hours (0.90 x 2208) and for the Tropical Western Pacific (TWP) locale is 1876.80 hours (0.85 x 2208). The first ARM Mobile Facility (AMF1) deployment in Graciosa Island, the Azores, Portugal, continued through this quarter, so the OPSMAX time this quarter is 2097.60 hours (0.95 x 2208). The second ARM Mobile Facility (AMF2) began deployment this quarter to Steamboat Springs, Colorado. The experiment officially began November 15, but most of the instruments were up and running by November 1. Therefore, the OPSMAX time for the AMF2 was 1390.80 hours (.95 x 1464 hours) for November and December (61 days). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It

  6. Use of spatial time-division repetition rate multiplication of mode-locked laser pulses to generate microwave radiation from optoelectronic switches

    NASA Astrophysics Data System (ADS)

    Mooradian, A.

    1984-09-01

    An all-optical technique is described which can substantially increase the pulse repetition rate of the output from any mode-locked laser. Multiplication of the repetition rate by a factor of 16 has been demonstrated. A mode-locked laser pulse train multiplied up to a 2-GHz repetition rate has been used to generate microwave radiation by means of a GaAs avalanche photodiode as well as an Fe:InP optoelectronic switch.

  7. Generation of scalable terahertz radiation from cylindrically focused two-color laser pulses in air

    NASA Astrophysics Data System (ADS)

    Kuk, D.; Yoo, Y. J.; Rosenthal, E. W.; Jhajj, N.; Milchberg, H. M.; Kim, K. Y.

    2016-03-01

    We demonstrate scalable terahertz (THz) generation by focusing terawatt, two-color laser pulses in air with a cylindrical lens. This focusing geometry creates a two-dimensional air plasma sheet, which yields two diverging THz lobe profiles in the far field. This setup can avoid plasma-induced laser defocusing and subsequent THz saturation, previously observed with spherical lens focusing of high-power laser pulses. By expanding the plasma source into a two-dimensional sheet, cylindrical focusing can lead to scalable THz generation. This scheme provides an energy conversion efficiency of 7 × 10-4, ˜7 times better than spherical lens focusing. The diverging THz lobes are refocused with a combination of cylindrical and parabolic mirrors to produce strong THz fields (>21 MV/cm) at the focal point.

  8. De-polarization of a CdZnTe radiation detector by pulsed infrared light

    SciTech Connect

    Dědič, V. Franc, J.; Rejhon, M.; Grill, R.; Zázvorka, J.; Sellin, P. J.

    2015-07-20

    This work is focused on a detailed study of pulsed mode infrared light induced depolarization of CdZnTe detectors operating at high photon fluxes. This depolarizing effect is a result of the decrease of positive space charge that is caused by the trapping of photogenerated holes at a deep level. The reduction in positive space charge is due to the optical transition of electrons from a valence band to the deep level due to additional infrared illumination. In this paper, we present the results of pulse mode infrared depolarization, by which it is possible to keep the detector in the depolarized state during its operation. The demonstrated mechanism represents a promising way to increase the charge collection efficiency of CdZnTe X-ray detectors operating at high photon fluxes.

  9. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    NASA Astrophysics Data System (ADS)

    Kavrigin, P.; Finocchiaro, P.; Griesmayer, E.; Jericha, E.; Pappalardo, A.; Weiss, C.

    2015-09-01

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a 6Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of 6Li(n,T)4He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in 6Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector.

  10. Cytotoxical products formation on the nanoparticles heated by the pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Kogan, Boris Ya.; Titov, Andrey A.; Rakitin, Victor Yu.; Kvacheva, Larisa D.; Kuzmin, Sergey G.; Vorozhtsov, Georgy N.

    2006-02-01

    Cytotoxical effect of a pulsed laser irradiation in presence of nanoparticles of carbon black, sulphuretted carbon and fullerene-60 on death of human uterus nick cancer HeLa and mice lymphoma P 388 cells was studied in vitro. Bubbles formation as result of "microexplosions" of nanoparticles is one of possible mechanisms of this effect. Other possible mechanism is cytotoxical products formation in result of pyrolysis of nanoparticles and biomaterial which is adjoining. The cytotoxical effect of addition of a supernatant from the carbon nanoparticles suspensions irradiated by the pulsed laser was studied to test this assumption. Analysis using gas chromatograph determined that carbon monoxide is principal gaseous product of such laser pyrolysis. This is known as cytotoxical product. Efficiency of its formation is estimated.

  11. Evolution of a finite pulse of radiation in a high-power free-electron laser

    SciTech Connect

    Ting, A.; Hafizi, B.; Sprangle, P.; Tang, C.M. . Plasma Physics Div.)

    1991-12-01

    The development of an optical pulse of finite axial extent is studied by means of an axisymmetric time-dependent particle simulation code for different rates of tapering of the wiggler field. The results provided in this paper illustrate a number of the physical phenomena underlying the free-electron laser mechanism. These include: suppression of the sideband instability; the role of gain focusing versus that of refractive guiding; efficiency enhancement; and pulse slippage. It is found that a significant reduction in the sideband modulation of the optical field can be achieved with a faster tapering of the wiggler parameters. Increasing the tapering rate also reduces refractive guiding, causing the optical wavefronts to become more convex, thus spreading the optical field into a larger cross section. The corresponding enhancement of the peak output power is associated with an increased lateral extent of the optical field rather than an increase in the field amplitude.

  12. Organic Crystal Growth Facility (OCGF) and Radiation Monitoring Container Device (RMCD) Groups in

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The primary payload for Space Shuttle Mission STS-42, launched January 22, 1992, was the International Microgravity Laboratory-1 (IML-1), a pressurized manned Spacelab module. The goal of IML-1 was to explore in depth the complex effects of weightlessness of living organisms and materials processing. Around-the-clock research was performed on the human nervous system's adaptation to low gravity and effects of microgravity on other life forms such as shrimp eggs, lentil seedlings, fruit fly eggs, and bacteria. Materials processing experiments were also conducted, including crystal growth from a variety of substances such as enzymes, mercury iodide, and a virus. The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Featured are activities of the Organic Crystal Growth Facility (OCGF) and Radiation Monitoring Container Device (RMCD) groups in the SL POCC during the IML-1 mission.

  13. Radiative shocks produced from spherical cryogenic implosions at the National Ignition Facility

    DOE PAGESBeta

    Pak, A.; Divol, L.; Gregori, G.; Weber, S.; Atherton, J.; Bennedetti, R.; Bradley, D. K.; Callahan, D.; Dewald, E.; Doppner, T.; et al

    2013-05-20

    Spherically expanding radiative shock waves have been observed from inertially confined implosion experiments at the National Ignition Facility. In these experiments, a spherical fusion target, initially 2 mm in diameter, is compressed via the pressure induced from the ablation of the outer target surface. At the peak compression of the capsule, x-ray and nuclear diagnostics indicate the formation of a central core, with a radius and ion temperature of ~20 μm and ~ 2 keV, respectively. This central core is surrounded by a cooler compressed shell of deuterium-tritium fuel that has an outer radius of ~40 μm and a densitymore » of >500 g/cm3. Using inputs from multiple diagnostics, the peak pressure of the compressed core has been inferred to be of order 100 Gbar for the implosions discussed here. Furthermore, the shock front, initially located at the interface between the high pressure compressed fuel shell and surrounding in-falling low pressure ablator plasma, begins to propagate outwards after peak compression has been reached.« less

  14. Radiative shocks produced from spherical cryogenic implosions at the National Ignition Facility

    SciTech Connect

    Pak, A.; Divol, L.; Gregori, G.; Weber, S.; Atherton, J.; Bennedetti, R.; Bradley, D. K.; Callahan, D.; Dewald, E.; Doppner, T.; Edwards, M. J.; Glenn, S.; Hicks, D.; Izumi, N.; Jones, O. S.; Khan, S. F.; Kilkenny, J. D.; Kline, J. L.; Kyrala, G. A.; Lindl, J.; Landen, O. L.; LePape, S.; Ma, T.; MacPhee, A.; MacGowan, B. J.; Mackinnon, A. J.; Masse, L.; Moody, J. D.; Moses, E. I.; Olson, R. E.; Ralph, J. E.; Park, H. -S.; Remmington, B. A.; Ross, J. S.; Tommasini, R.; Town, R. P. J.; Smalyuk, V.; Glenzer, S. H.; Hsing, W. W.; Robey, H. F.; Grim, G. P.; Frenje, J. A.; Casey, D. T.; Johnson, M. G.

    2013-05-20

    Spherically expanding radiative shock waves have been observed from inertially confined implosion experiments at the National Ignition Facility. In these experiments, a spherical fusion target, initially 2 mm in diameter, is compressed via the pressure induced from the ablation of the outer target surface. At the peak compression of the capsule, x-ray and nuclear diagnostics indicate the formation of a central core, with a radius and ion temperature of ~20 μm and ~ 2 keV, respectively. This central core is surrounded by a cooler compressed shell of deuterium-tritium fuel that has an outer radius of ~40 μm and a density of >500 g/cm3. Using inputs from multiple diagnostics, the peak pressure of the compressed core has been inferred to be of order 100 Gbar for the implosions discussed here. Furthermore, the shock front, initially located at the interface between the high pressure compressed fuel shell and surrounding in-falling low pressure ablator plasma, begins to propagate outwards after peak compression has been reached.

  15. 1-2 GeV synchrotron radiation facility at Lawrence Berkeley Laboratory

    SciTech Connect

    Berkner, K.H.

    1985-10-01

    The Advanced Light Source (ALS), a dedicated synchrotron radiation facility optimized to generate soft x-ray and vacuum ultraviole (XUV) light using magnetic insertion devices, was proposed by the Lawrence Berkeley Laboratory in 1982. It consists of a 1.3-GeV injection system, an electron storage ring optimized at 1.3 GeV (with the capability of 1.9-GeV operation), and a number of photon beamlines emanating from twelve 6-meter-long straight sections, as shown in Fig. 1. In addition, 24 bending-magnet ports will be avialable for development. The ALS was conceived as a research tool whose range and power would stimulate fundamentally new research in fields from biology to materials science (1-4). The conceptual design and associated cost estimate for the ALS have been completed and reviewed by the US Department of Energy (DOE), but preliminary design activities have not yet begun. The focus in this paper is on the history of the ALS as an example of how a technical construction project was conceived, designed, proposed, and validated within the framwork of a national laboratory funded largely by the DOE.

  16. The U.S. Department of Energy's Atmospheric Radiation Measurement Climate Research Facilities on the North Slope of Alaska

    NASA Astrophysics Data System (ADS)

    Ivey, M. D.; Verlinde, J.; Richardson, S.; Zak, B.; Zirzow, J.

    2008-12-01

    The U.S. Department of Energy (DOE) provides scientific infrastructure and data archives to the international Arctic research community through a national user facility, the ARM Climate Research Facilities (ACRF). One of three fixed ARM Climate Research Facilities is located on the North Slope of Alaska. Since 1998, these facilities near the communities of Barrow and Atqasuk have provided data about cloud and radiative processes at high latitudes. These data are used to refine models and parameterizations related to the Arctic. Data records from the instruments at these facilities and data products are available through web- accessible archives. The ACRF's role is to provide infrastructure support for climate research, including Arctic research, to the global scientific community. DOE's climate research programs, with a focus on clouds and aerosols and their impact on the radiative budget, define the research scope supported by the Facility. In addition to a set of baseline instruments at the two fixed North Slope ACRF locations, temporary or guest instruments are operated as required to support field campaigns. Recent field campaigns have included over-flights by aircraft with cloud and aerosol-sampling instrumentation. To support proposed deployments of unmanned aerial vehicle and unmanned aerial systems on the North Slope of Alaska and over the Arctic Ocean, permissions are being obtained and access arranged for use of a runway and nearby ground support facilities at Oliktok Point, Alaska. In addition to the fixed facilities, ARM Mobile Facilities may be used for high-latitude deployments. Deployments for the ARM Mobile Facilities are selected through a formal process that includes peer review of science-focused proposals. The first ARM Mobile Facility is nearing the end of a deployment in China. Design and development of a second ARM Mobile Facility will begin in late calendar year 2008. This paper discusses the scientific infrastructure, data streams and

  17. Invited Article: A test-facility for large-area microchannel plate detector assemblies using a pulsed sub-picosecond laser

    NASA Astrophysics Data System (ADS)

    Adams, Bernhard; Chollet, Matthieu; Elagin, Andrey; Oberla, Eric; Vostrikov, Alexander; Wetstein, Matthew; Obaid, Razib; Webster, Preston

    2013-06-01

    The Large Area Picosecond Photodetector Collaboration is developing large-area fast photodetectors with time resolution ≲10 ps and space resolution ≲1 mm based on atomic layer deposition-coated glass Micro-Channel Plates (MCPs). We have assembled a facility at Argonne National Laboratory for characterizing the performance of a wide variety of microchannel plate configurations and anode structures in configurations approaching complete detector systems. The facility consists of a pulsed Ti:Sapphire laser with a pulse duration ≈100 fs, an optical system allowing the laser to be scanned in two dimensions, and a computer-controlled data-acquisition system capable of reading out 60 channels of anode signals with a sampling rate of over 10 GS/s. The laser can scan on the surface of a sealed large-area photodetector, or can be introduced into a large vacuum chamber for tests on bare 8 in.-square MCP plates or into a smaller chamber for tests on 33-mm circular substrates. We present the experimental setup, detector calibration, data acquisition, analysis tools, and typical results demonstrating the performance of the test facility.

  18. The planning, construction, and operation of a radioactive waste storage facility for an Australian state radiation regulatory authority

    SciTech Connect

    Wallace, J.D.; Kleinschmidt, R.; Veevers, P.

    1995-12-31

    Radiation regulatory authorities have a responsibility for the management of radioactive waste. This, more often than not, includes the collection and safe storage of radioactive sources in disused radiation devices and devices seized by the regulatory authority following an accident, abandonment or unauthorised use. The public aversion to all things radioactive, regardless of the safety controls, together with the Not In My Back Yard (NIMBY) syndrome combine to make the establishment of a radioactive materials store a near impossible task, despite the fact that such a facility is a fundamental tool for regulatory authorities to provide for the radiation safety of the public. In Queensland the successful completion and operational use of such a storage facility has taken a total of 8 years of concerted effort by the staff of the regulatory authority, the expenditure of over $2 million (AUS) not including regulatory staff costs and the cost of construction of an earlier separate facility. This paper is a summary of the major developments in the planning, construction and eventual operation of the facility including technical and administrative details, together with the lessons learned from the perspective of the overall project.

  19. SAS 2 observation of pulsed high-energy gamma radiation from Geminga

    NASA Technical Reports Server (NTRS)

    Mattox, J. R.; Bertsch, D. L.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.

    1992-01-01

    Following the detection of pulsed X-rays and gamma rays from Geminga, the 1972-1973 SAS 2 data which first revealed this source have been reanalyzed. The 237 ms periodicity is visible in those observations. The phase of the SAS 2 periodicity is consistent with that of COS B suggesting that the gamma-ray data allow an accounting for every revolution of the Geminga pulsar between 1972 and 1982.

  20. Changes in the emission properties of metallic targets upon exposure to repetitively pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Konov, V. I.; Pimenov, S. M.; Prokhorov, A. M.; Chapliev, N. I.

    1988-02-01

    A scanning electron microscope and a repetitively pulsed CO2 laser are used to reveal the relationships which govern the correlation of the transforming metal surface microrelief with the emission of charged particles and the surface luminescence upon exposure to multipulse laser focusing. It is shown that the effect of sorption and laser-stimulated desorption on the emission signals can manifest itself in different ways depending on the current oscillation mode in the target-vacuum chamber circuit.