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Sample records for alamos radiation transport

  1. Recent developments in the Los Alamos radiation transport code system

    SciTech Connect

    Forster, R.A.; Parsons, K.

    1997-06-01

    A brief progress report on updates to the Los Alamos Radiation Transport Code System (LARTCS) for solving criticality and fixed-source problems is provided. LARTCS integrates the Diffusion Accelerated Neutral Transport (DANT) discrete ordinates codes with the Monte Carlo N-Particle (MCNP) code. The LARCTS code is being developed with a graphical user interface for problem setup and analysis. Progress in the DANT system for criticality applications include a two-dimensional module which can be linked to a mesh-generation code and a faster iteration scheme. Updates to MCNP Version 4A allow statistical checks of calculated Monte Carlo results.

  2. Radiation Transport

    SciTech Connect

    Urbatsch, Todd James

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  3. Inner Radiation Belt Representation of the Energetic Electron Environment: Model and Data Synthesis Using the Salammbo Radiation Belt Transport Code and Los Alamos Geosynchronous and GPS Energetic Particle Data

    NASA Technical Reports Server (NTRS)

    Friedel, R. H. W.; Bourdarie, S.; Fennell, J.; Kanekal, S.; Cayton, T. E.

    2004-01-01

    The highly energetic electron environment in the inner magnetosphere (GEO inward) has received a lot of research attention in resent years, as the dynamics of relativistic electron acceleration and transport are not yet fully understood. These electrons can cause deep dielectric charging in any space hardware in the MEO to GEO region. We use a new and novel approach to obtain a global representation of the inner magnetospheric energetic electron environment, which can reproduce the absolute environment (flux) for any spacecraft orbit in that region to within a factor of 2 for the energy range of 100 KeV to 5 MeV electrons, for any levels of magnetospheric activity. We combine the extensive set of inner magnetospheric energetic electron observations available at Los Alamos with the physics based Salammbo transport code, using the data assimilation technique of "nudging". This in effect input in-situ data into the code and allows the diffusion mechanisms in the code to interpolate the data into regions and times of no data availability. We present here details of the methods used, both in the data assimilation process and in the necessary inter-calibration of the input data used. We will present sample runs of the model/data code and compare the results to test spacecraft data not used in the data assimilation process.

  4. Penetrating radiation: applications at Los Alamos National Laboratory

    NASA Astrophysics Data System (ADS)

    Watson, Scott; Hunter, James; Morris, Christopher

    2013-09-01

    Los Alamos has used penetrating radiography extensively throughout its history dating back to the Manhattan Project where imaging dense, imploding objects was the subject of intense interest. This interest continues today as major facilities like DARHT1 have become the mainstay of the US Stockpile Stewardship Program2 and the cornerstone of nuclear weapons certification. Meanwhile, emerging threats to national security from cargo containers and improvised explosive devices (IEDs) have invigorated inspection efforts using muon tomography, and compact x-ray radiography. Additionally, unusual environmental threats, like those from underwater oil spills and nuclear power plant accidents, have caused renewed interest in fielding radiography in severe operating conditions. We review the history of penetrating radiography at Los Alamos and survey technologies as presently applied to these important problems.

  5. Introduction to radiation transport

    SciTech Connect

    Olson, G.L.

    1998-12-31

    This lecture will present time-dependent radiation transport where the radiation is coupled to a static medium, i.e., the material is not in motion. In reality, radiation exerts a pressure on the materials it propagates through and will accelerate the material in the direction of the radiation flow. This fully coupled problem with radiation transport and materials in motion is referred to as radiation-hydrodynamics (or in a shorthand notation: rad-hydro) and is beyond the scope of this lecture.

  6. 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.

  7. THE LOS ALAMOS NATIONAL LABORATORY ATMOSPHERIC TRANSPORT AND DIFFUSION MODELS

    SciTech Connect

    M. WILLIAMS

    1999-08-01

    The LANL atmospheric transport and diffusion models are composed of two state-of-the-art computer codes. The first is an atmospheric wind model called HOThlAC, Higher Order Turbulence Model for Atmospheric circulations. HOTMAC generates wind and turbulence fields by solving a set of atmospheric dynamic equations. The second is an atmospheric diffusion model called RAPTAD, Random Particle Transport And Diffusion. RAPTAD uses the wind and turbulence output from HOTMAC to compute particle trajectories and concentration at any location downwind from a source. Both of these models, originally developed as research codes on supercomputers, have been modified to run on microcomputers. Because the capability of microcomputers is advancing so rapidly, the expectation is that they will eventually become as good as today's supercomputers. Now both models are run on desktop or deskside computers, such as an IBM PC/AT with an Opus Pm 350-32 bit coprocessor board and a SUN workstation. Codes have also been modified so that high level graphics, NCAR Graphics, of the output from both models are displayed on the desktop computer monitors and plotted on a laser printer. Two programs, HOTPLT and RAPLOT, produce wind vector plots of the output from HOTMAC and particle trajectory plots of the output from RAPTAD, respectively. A third CONPLT provides concentration contour plots. Section II describes step-by-step operational procedures, specifically for a SUN-4 desk side computer, on how to run main programs HOTMAC and RAPTAD, and graphics programs to display the results. Governing equations, boundary conditions and initial values of HOTMAC and RAPTAD are discussed in Section III. Finite-difference representations of the governing equations, numerical solution procedures, and a grid system are given in Section IV.

  8. Measurement and modeling of external radiation during 1985 from LAMPF (Los Alamos Meson Physics Facility) emissions

    SciTech Connect

    Bowen, B.M.; Olsen, W.A.; Chen, Ili; Van Etten, D.M.

    1987-11-01

    An array of three portable, pressurized ionization chambers (PICs) continued to measure external radiation levels during 1985 caused by radionuclides emitted from the Los Alamos Meson Physics Facility (LAMPF). A Gaussian-type atmospheric dispersion model, using onsite meteorological and stack release data, was tested during this study. A more complex finite model, which takes into account the contribution of radiation at a receptor from different locations of the passing plume, was also tested. Monitoring results indicate that, as in 1984, a persistent wind up the Rio Grande Valley during the evening and early morning hours is largely responsible for causing the highest external radiation levels to occur to the northeast and north-northeast of LAMPF. However, because of increased turbulent mixing during the day, external radiation levels are generally much less during the day than at night. External radiation levels during 1985 show approximately a 75% reduction over 1984 levels. This resulted from a similar percentage reduction in LAMPF emissions caused by newly implemented emission controls. Comparison of predicted and measured daily external radiation levels indicates a high degree of correlation. The model also gives accurate estimates of measured concentrations over longer time periods. Comparison of predicted and measured hourly values indicates that the model generally tends to overpredict during the day and underpredict at night. 9 refs., 14 figs., 13 tabs.

  9. The Los Alamos dynamic radiation environment assimilation model (DREAM) for space weather specification and forecasting

    SciTech Connect

    Reeves, Geoffrey D; Friedel, Reiner H W; Chen, Yue; Koller, Josef; Henderson, Michael G

    2008-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at Los Alamos National Laboratory to assess, quantify, and predict the hazards from the natural space environment and the anthropogenic environment produced by high altitude nuclear explosions (HANE). DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's Van Allen radiation belts. It uses Kalman filter techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts. DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity by assigning appropriate uncertainties to the observations. Data from any spacecraft orbit can be assimilated but DREAM was designed to function with as few as two spacecraft inputs: one from geosynchronous orbit and one from GPS orbit. With those inputs, DREAM can be used to predict the environment at any satellite in any orbit whether space environment data are available in those orbits or not. Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy. DREAM has been extensively tested and evaluated as we transition from research to operations. We report here on one set of test results in which we predict the environment in a highly-elliptical polar orbit. We also discuss long-duration reanalysis for spacecraft design, using DREAM for real-time operations, and prospects for 1-week forecasts of the radiation belt environment.

  10. Radiation transport calculations for cosmic radiation.

    PubMed

    Endo, A; Sato, T

    2012-01-01

    The radiation environment inside and near spacecraft consists of various components of primary radiation in space and secondary radiation produced by the interaction of the primary radiation with the walls and equipment of the spacecraft. Radiation fields inside astronauts are different from those outside them, because of the body's self-shielding as well as the nuclear fragmentation reactions occurring in the human body. Several computer codes have been developed to simulate the physical processes of the coupled transport of protons, high-charge and high-energy nuclei, and the secondary radiation produced in atomic and nuclear collision processes in matter. These computer codes have been used in various space radiation protection applications: shielding design for spacecraft and planetary habitats, simulation of instrument and detector responses, analysis of absorbed doses and quality factors in organs and tissues, and study of biological effects. This paper focuses on the methods and computer codes used for radiation transport calculations on cosmic radiation, and their application to the analysis of radiation fields inside spacecraft, evaluation of organ doses in the human body, and calculation of dose conversion coefficients using the reference phantoms defined in ICRP Publication 110.

  11. Los Alamos Science: Number 23, 1995. Radiation protection and the human radiation experiments

    SciTech Connect

    Cooper, N.G.

    1995-12-31

    There are a variety of myths and misconceptions about the ionizing radiation that surrounds and penetrates us all. Dispel a few of these by taking a leisurely tour of radiation and its properties, of the natural and man-made sources of ionizing radiation, and of the way doses are calculated. By damaging DNA and inducing genetic mutations, ionizing radiation can potentially initiate a cell on the road to cancer. The authors review what is currently known about regulation of cellular reproduction, DNA damage and repair, cellular defense mechanisms, and the specific cancer-causing genes that are susceptible to ionizing radiation. A rapid survey of the data on radiation effects in humans shows that high radiation doses increase the risk of cancer, whereas the effects of low doses are very difficult to detect. The hypothetical risks at low doses, which are estimated from the atomic-bomb survivors, are compared to the low-dose data so that the reader can assess the present level of uncertainty. As part of the openness initiative, ten individuals who have worked with plutonium during various periods in the Laboratory`s history were asked to share their experiences including their accidental intakes. The history and prognosis of people who have had plutonium exposures is discussed by the Laboratory`s leading epidemiologist.

  12. Hydrologic transport of depleted uranium associated with open air dynamic range testing at Los Alamos National Laboratory, New Mexico, and Eglin Air Force Base, Florida

    SciTech Connect

    Becker, N.M.; Vanta, E.B.

    1995-05-01

    Hydrologic investigations on depleted uranium fate and transport associated with dynamic testing activities were instituted in the 1980`s at Los Alamos National Laboratory and Eglin Air Force Base. At Los Alamos, extensive field watershed investigations of soil, sediment, and especially runoff water were conducted. Eglin conducted field investigations and runoff studies similar to those at Los Alamos at former and active test ranges. Laboratory experiments complemented the field investigations at both installations. Mass balance calculations were performed to quantify the mass of expended uranium which had transported away from firing sites. At Los Alamos, it is estimated that more than 90 percent of the uranium still remains in close proximity to firing sites, which has been corroborated by independent calculations. At Eglin, we estimate that 90 to 95 percent of the uranium remains at test ranges. These data demonstrate that uranium moves slowly via surface water, in both semi-arid (Los Alamos) and humid (Eglin) environments.

  13. Data Intensive Simulation and Analysis of Groundwater Flow and Transport in the Los Alamos aquifer

    NASA Astrophysics Data System (ADS)

    Mishra, P. K.; Harp, D.; Miller, T. A.; Vesselinov, V. V.

    2011-12-01

    Characterization of the groundwater flow and transport in regional aquifer systems is a challenging task. In most practical cases, there is not sufficient hydrogeologic information that can be applied to evaluate aquifer properties. In addition, the development, execution and analyses of large-scale numerical models are computational demanding requiring advanced high-performance codes and state-of-the-art computational resources. We have developed a complex 3D regional groundwater flow model of the regional aquifer beneath the Los Alamos National Laboratory (LANL) site to provide a better understanding of hydrogeologic properties, recharge sources, groundwater travel times, migration pathways for potential contaminants, and potential contaminant concentrations at water supply wells. The 3D computational grid is generated using sophisticated grid generating software, LaGriT (http://lagrit.lanl.gov). LaGriT allows the use of unstructured meshing strategies, which capture the details of complex groundwater flow of the LANL site, including wellbore geometries and hydrostratigraphy. The numerical simulation is performed using the FEHM (Finite Element Heat and Mass transfer) (http://fehm.lanl.gov) codes. Long-term groundwater level monitoring at LANL started in the mid-1940s; the monitoring data is currently collected at more than 70 regional monitoring wells providing an extensive water-level observation data set. The water-level data represent over 62 years of recorded drawdowns and recovery caused by the spatially and temporally variable pumping at six municipal water-supply wells. The water-level data is applied in the 3D flow model to inversely estimate the aquifer parameters. The model calibration, uncertainty quantification, and sensitivity analyses are performed using the code MADS (Model Analyses and Decision Support; http://ees.lanl.gov/staff/monty/codes/mads). The research utilizes high performance computational resources (multiprocessor clusters) at LANL. In

  14. Status of Monte Carlo at Los Alamos

    SciTech Connect

    Thompson, W.L.; Cashwell, E.D.

    1980-01-01

    At Los Alamos the early work of Fermi, von Neumann, and Ulam has been developed and supplemented by many followers, notably Cashwell and Everett, and the main product today is the continuous-energy, general-purpose, generalized-geometry, time-dependent, coupled neutron-photon transport code called MCNP. The Los Alamos Monte Carlo research and development effort is concentrated in Group X-6. MCNP treats an arbitrary three-dimensional configuration of arbitrary materials in geometric cells bounded by first- and second-degree surfaces and some fourth-degree surfaces (elliptical tori). Monte Carlo has evolved into perhaps the main method for radiation transport calculations at Los Alamos. MCNP is used in every technical division at the Laboratory by over 130 users about 600 times a month accounting for nearly 200 hours of CDC-7600 time.

  15. Radiation Transport in Dynamic Spacetimes

    NASA Astrophysics Data System (ADS)

    Schnittman, Jeremy; Baker, John; Etienne, Zachariah; Giacomazzo, Bruno; Kelly, Bernard

    2017-01-01

    We present early results from a new radiation transport calculation of gas accretion onto merging binary black holes. We use the Monte Carlo radiation transport code Pandurata, now generalized for application to dynamic spacetimes. The time variability of the metric requires careful numerical techniques for solving the geodesic equation, particularly with tabulated spacetime data from numerical relativity codes. Using a new series of general relativistic magneto-hydrodynamical simulations of magnetized flow onto binary black holes, we investigate the possibility for detecting and identifying unique electromagnetic counterparts to gravitational wave events.

  16. FY2008 Report on GADRAS Radiation Transport Methods.

    SciTech Connect

    Mattingly, John.; Mitchell, Dean J; Harding, Lee T.; Varley, Eric S.; Hilton, Nathan R.

    2008-10-01

    The primary function of the Gamma Detector Response and Analysis Software (GADRAS) is the solution of inverse radiation transport problems, by which the con-figuration of an unknown radiation source is inferred from one or more measured radia-tion signatures. GADRAS was originally developed for the analysis of gamma spec-trometry measurements. During fiscal years 2007 and 2008, GADRAS was augmented to implement the simultaneous analysis of neutron multiplicity measurements. This report describes the radiation transport methods developed to implement this new capability. This work was performed at the direction of the National Nuclear Security Administration's Office of Nonproliferation Research and Development. It was executed as an element of the Proliferation Detection Program's Simulation, Algorithm, and Modeling element. Acronyms BNL Brookhaven National Laboratory CSD Continuous Slowing-Down DU depleted uranium ENSDF Evaluated Nuclear Structure Data Files GADRAS Gamma Detector Response and Analysis Software HEU highly enriched uranium LANL Los Alamos National Laboratory LLNL Lawrence Livermore National Laboratory NA-22 Office of Nonproliferation Research and Development NNDC National Nuclear Data Center NNSA National Nuclear Security Administration ODE ordinary differential equation ONEDANT One-dimensional diffusion accelerated neutral particle transport ORNL Oak Ridge National Laboratory PARTISN Parallel time-dependent SN PDP Proliferation Detection Program RADSAT Radiation Scenario Analysis Toolkit RSICC Radiation Safety Information Computational Center SAM Simulation, Algorithms, and Modeling SNL Sandia National Laboratories SNM special nuclear material ToRI Table of Radioactive Isotopes URI uniform resource identifier XML Extensible Markup Language

  17. Comparison of beam transport simulations to measurements at the Los Alamos Proton Storage Ring

    SciTech Connect

    Wilkinson, C.; Neri, F.; Fitzgerald, D.H.; Blind, B.; Macek, R.; Plum, M.; Sander, O.; Thiessen, H.A.

    1997-10-01

    The ability to model and simulate beam behavior in the Proton Storage Ring (PSR) of the Los Alamos Neutron Science Center (LANSCE) is an important diagnostic and predictive tool. This paper gives the results of an effort to model the ring apertures and lattice and use beam simulation programs to track the beam. The results are then compared to measured activation levels from beam loss in the ring. The success of the method determines its usefulness in evaluating the effects of planned upgrades to the Proton Storage Ring.

  18. Space Radiation Transport Methods Development

    NASA Astrophysics Data System (ADS)

    Wilson, J.; Tripathi, R.; Qualls, G.; Cucinotta, F.; Prael, R.; Norbury, J.

    Early space radiation shield code development relied on Monte Carlo methods for proton, neutron and pion transport and made important contributions to the space program. More recently Monte Carlo code LAHET has been upgraded to include high-energy multiple-charged light ions for GCR simulations and continues to be expanded in capability. To compensate for low computational efficiency, Monte Carlo methods have resorted to restricted one-dimensional problems leading to imperfect representations of appropriate boundary conditions. Even so, intensive computational requirements resulted and shield evaluation was made near the end of the design process and resolving shielding issues usually had a negative impact on the design. We evaluate the implications of these common one-dimensional assumptions on the evaluation of the Shuttle internal radiation field. Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 milliseconds and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of reconfigurable computing and could be

  19. The Radiation Transport Conundrum in Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2005-03-18

    The summary of this paper is: (1) The conundrum in the title is whether to treat radiation in the lab frame or the comoving frame in a radiation-hydrodynamic problem; (2) Several of the difficulties are associated with combining a somewhat relativistic treatment of radiation with a non-relativistic treatment of hydrodynamics; (3) The principal problem is a tradeoff between easily obtaining the correct diffusion limit and describing free-streaming radiation with the correct wave speed; (4) The computational problems of the comoving-frame formulation in more than one dimension, and the difficulty of obtaining both exact conservation and full u/c accuracy argue against this method; (5) As the interest in multi-D increases, as well as the power of computers, the lab-frame method is becoming more attractive; and (6) The Monte Carlo method combines the advantages of both lab-frame and comoving-frame approaches, its only disadvantage being cost.

  20. Coupled electron-photon radiation transport

    SciTech Connect

    Lorence, L.; Kensek, R.P.; Valdez, G.D.; Drumm, C.R.; Fan, W.C.; Powell, J.L.

    2000-01-17

    Massively-parallel computers allow detailed 3D radiation transport simulations to be performed to analyze the response of complex systems to radiation. This has been recently been demonstrated with the coupled electron-photon Monte Carlo code, ITS. To enable such calculations, the combinatorial geometry capability of ITS was improved. For greater geometrical flexibility, a version of ITS is under development that can track particles in CAD geometries. Deterministic radiation transport codes that utilize an unstructured spatial mesh are also being devised. For electron transport, the authors are investigating second-order forms of the transport equations which, when discretized, yield symmetric positive definite matrices. A novel parallelization strategy, simultaneously solving for spatial and angular unknowns, has been applied to the even- and odd-parity forms of the transport equation on a 2D unstructured spatial mesh. Another second-order form, the self-adjoint angular flux transport equation, also shows promise for electron transport.

  1. Los Alamos Radiation Hydrocode Models of Asteroid Destruction by an Internal Explosion

    NASA Astrophysics Data System (ADS)

    Weaver, R.; Plesko, C. S.

    2009-12-01

    Disruption of a potentially hazardous object (PHO) by a conventional or nuclear subsurface burst is considered has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center of such PHO models (10 Mton TNT equivalent) , specifically for Itokawa and Golevka. If possible, our RAGE model calculations will be compared to M. Boslough’s (Sandia National Laboratory) results from his similar simulations with a different code. As time permits, parametric studies will be done on source energy (from 1 Mton to 10 Mton) and on the parameters in the Steinberg-Guinan strength model used.

  2. Los Alamos Radiation Hydrocode Models of Asteroid Mitigation by a Subsurface Explosion

    NASA Astrophysics Data System (ADS)

    Weaver, R.; Plesko, C. S.; Dearholt, W.

    2010-12-01

    Mitigation of a potentially hazardous object (PHO) by a nuclear subsurface explosion is considered. In this new work we examine non-central subsurface emplacements and seek an optimal depth-of-burial for various explosion energies. This intervention methodology has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present new RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts and deflection from shallow buried bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center and near the edge (mitigation) of such PHO models (1-10 Mton TNT equivalent), specifically for asteroid 25143 Itokawa. Parametric studies will be done on: the value of the source energy (from 100 Kton to 10 Mton), the parameters in the Steinberg-Guinan strength model used and the internal composition of the object from uniform composition to a “rubble pile” distribution. Specifically we are interested in assessing the optimum depth of burial and energy required to essentially disrupt and/or move the PHO and therefore mitigate the hazard. Recollection will be considered. (LA-UR-10-05860) A subsurface 1 Mt explosion near the long-axis surface of an Itokawa shape model with a non-uniform internal composition. The resulting velocity imparted to the bulk remainder of the object is ~50 m/s.

  3. Los Alamos Radiation Hydrocode Models of Asteroid Mitigation by an Internal Explosion

    NASA Astrophysics Data System (ADS)

    Weaver, Robert; Plesko, C.; Dearholdt, W.

    2010-10-01

    Mitigation of a potentially hazardous object (PHO) by a conventional or nuclear subsurface burst is considered. This intervention methodology has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts and deflection from shallow buried bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center and near the edge (mitigation) of such PHO models (1-10 Mton TNT equivalent), specifically for asteroid 25143 Itokawa. Parametric studies will be done on: the value of the source energy (from 1 Mton to 10 Mton), the parameters in the Steinberg-Guinan strength model used and the internal composition of the object from uniform composition to a "rubble pile” distribution. Specifically we are interested in assessing the optimum depth of burial and energy required to essentially disrupt and/or move the PHO and therefore mitigate the hazard. Recollection will be considered.

  4. [Problems of radiation hygiene in railway transport].

    PubMed

    Freĭman, E S

    1995-01-01

    Railway radiation hygiene is a modern trend of research. The main problems in this sphere are as follows: hygienic assessment of utilization of railway sources in railway objects; safe transportation of radioactive agents; prevention of accidents in railway transport; radiobiological examinations of workers, etc.

  5. 3D unstructured-mesh radiation transport codes

    SciTech Connect

    Morel, J.

    1997-12-31

    Three unstructured-mesh radiation transport codes are currently being developed at Los Alamos National Laboratory. The first code is ATTILA, which uses an unstructured tetrahedral mesh in conjunction with standard Sn (discrete-ordinates) angular discretization, standard multigroup energy discretization, and linear-discontinuous spatial differencing. ATTILA solves the standard first-order form of the transport equation using source iteration in conjunction with diffusion-synthetic acceleration of the within-group source iterations. DANTE is designed to run primarily on workstations. The second code is DANTE, which uses a hybrid finite-element mesh consisting of arbitrary combinations of hexahedra, wedges, pyramids, and tetrahedra. DANTE solves several second-order self-adjoint forms of the transport equation including the even-parity equation, the odd-parity equation, and a new equation called the self-adjoint angular flux equation. DANTE also offers three angular discretization options: $S{_}n$ (discrete-ordinates), $P{_}n$ (spherical harmonics), and $SP{_}n$ (simplified spherical harmonics). DANTE is designed to run primarily on massively parallel message-passing machines, such as the ASCI-Blue machines at LANL and LLNL. The third code is PERICLES, which uses the same hybrid finite-element mesh as DANTE, but solves the standard first-order form of the transport equation rather than a second-order self-adjoint form. DANTE uses a standard $S{_}n$ discretization in angle in conjunction with trilinear-discontinuous spatial differencing, and diffusion-synthetic acceleration of the within-group source iterations. PERICLES was initially designed to run on workstations, but a version for massively parallel message-passing machines will be built. The three codes will be described in detail and computational results will be presented.

  6. Radiation Transport Calculations and Simulations

    SciTech Connect

    Fasso, Alberto; Ferrari, A.; /CERN

    2011-06-30

    This article is an introduction to the Monte Carlo method as used in particle transport. After a description at an elementary level of the mathematical basis of the method, the Boltzmann equation and its physical meaning are presented, followed by Monte Carlo integration and random sampling, and by a general description of the main aspects and components of a typical Monte Carlo particle transport code. In particular, the most common biasing techniques are described, as well as the concepts of estimator and detector. After a discussion of the different types of errors, the issue of Quality Assurance is briefly considered.

  7. Radiative transport in large arteries

    PubMed Central

    Ruh, Dominic; Subramanian, Sivaraman; Theodor, Michael; Zappe, Hans; Seifert, Andreas

    2013-01-01

    A refined model for the photon energy distribution in a living artery is established by solving the radiative transfer equation in a cylindrical geometry, using the Monte Carlo method. Combining this model with the most recent experimental values for the optical properties of flowing blood and the biomechanics of a blood-filled artery subject to a pulsatile pressure, we find that the optical intensity transmitted through large arteries decreases linearly with increasing arterial distension. This finding provides a solid theoretical foundation for measuring photoplethysmograms. PMID:24466476

  8. Environmental analysis of Lower Pueblo/Lower Los Alamos Canyon, Los Alamos, New Mexico

    SciTech Connect

    Ferenbaugh, R.W.; Buhl, T.E.; Stoker, A.K.; Becker, N.M.; Rodgers, J.C.; Hansen, W.R.

    1994-12-01

    The radiological survey of the former radioactive waste treatment plant site (TA-45), Acid Canyon, Pueblo Canyon, and Los Alamos Canyon found residual contamination at the site itself and in the channel and banks of Acid, Pueblo, and lower Los Alamos Canyons all the way to the Rio Grande. The largest reservoir of residual radioactivity is in lower Pueblo Canyon, which is on DOE property. However, residual radioactivity does not exceed proposed cleanup criteria in either lower Pueblo or lower Los Alamos Canyons. The three alternatives proposed are (1) to take no action, (2) to construct a sediment trap in lower Pueblo Canyon to prevent further transport of residual radioactivity onto San Ildefonso Indian Pueblo land, and (3) to clean the residual radioactivity from the canyon system. Alternative 2, to cleanup the canyon system, is rejected as a viable alternative. Thousands of truckloads of sediment would have to be removed and disposed of, and this effort is unwarranted by the low levels of contamination present. Residual radioactivity levels, under either present conditions or projected future conditions, will not result in significant radiation doses to persons exposed. Modeling efforts show that future transport activity will not result in any residual radioactivity concentrations higher than those already existing. Thus, although construction of a sediment trap in lower Pueblo Canyon is a viable alternative, this effort also is unwarranted, and the no-action alternative is the preferred alternative.

  9. Space Radiation Transport Methods Development

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Tripathi, R. K.; Qualls, G. D.; Cucinotta, F. A.; Prael, R. E.; Norbury, J. W.; Heinbockel, J. H.; Tweed, J.

    2002-01-01

    Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 milliseconds and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of reconfigurable computing and could be utilized in the final design as verification of the deterministic method optimized design.

  10. Radiation Transport in Type IA Supernovae

    SciTech Connect

    Eastman, R

    1999-11-16

    It has been said more than once that the critical link between explosion models and observations is the ability to accurately simulate cooling and radiation transport in the expanding ejecta of Type Ia supernovae. It is perhaps frustrating to some of the theorists who study explosion mechanisms, and to some of the observers too, that more definitive conclusions have not been reached about the agreement, or lack thereof, between various Type Ia supernova models and the data. Although claims of superlative accuracy in transport simulations are sometimes made, I will argue here that there are outstanding issues of critical importance and in need of addressing before radiation transport calculations are accurate enough to discriminate between subtly different explosion models.

  11. RADIATION TRANSPORT FOR EXPLOSIVE OUTFLOWS: OPACITY REGROUPING

    SciTech Connect

    Wollaeger, Ryan T.; Van Rossum, Daniel R. E-mail: daan@flash.uchicago.edu

    2014-10-01

    Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure ''opacity regrouping''. Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in SuperNu, a code designed to do radiation transport in high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck factor for modified IMC-DDMC. We test SuperNu using numerical experiments including a quasi-manufactured analytic solution, a simple 10 group problem, and the W7 problem for Type Ia supernovae. We find that opacity regrouping is necessary to make our IMC-DDMC implementation feasible for the W7 problem and possibly Type Ia supernova simulations in general. We compare the bolometric light curves and spectra produced by the SuperNu and PHOENIX radiation transport codes for the W7 problem. The overall shape of the bolometric light curves are in good agreement, as are the spectra and their evolution with time. However, for the numerical specifications we considered, we find that the peak luminosity of the light curve calculated using SuperNu is ∼10% less than that calculated using PHOENIX.

  12. Environmental surveillance at Los Alamos during 1994

    SciTech Connect

    1996-07-01

    This report describes environmental monitoring activities at Los Alamos National Laboratory for 1994. Data were collected to assess external penetrating radiation, airborne emissions, liquid effluents, radioactivity of environmental materials and food stuffs, and environmental compliance.

  13. Comparison and analysis of 2-D simulation results with two implosion radiation experiments on the Los Alamos Pegasus I and Pegasus II capacitor banks

    SciTech Connect

    Peterson, D.L.; Bowers, R.L.; Lebeda, C.F.; Matuska, W.; Benage, J.; Idzorek, G.; Oona, H.; Stokes, J.; Roderick, N.F.

    1995-09-01

    Two experiments, PegI-41, conducted on the Los Alamos Pegasus I capacitor bank, and PegII-25, on the Pegasus II bank, consisted of the implosions of 13 mg (nominal), 5 cm radius, 2 cm high thin cylindrical aluminum foils resulting in soft x-ray radiation pulses from the plasma thermalization on axis. The implosions were conducted in direct-drive (no intermediate switching) mode with peak currents of about 4 MA and 5 MA respectively, and implosion times of about 2.5 {micro}s and 2.0 {micro}s. A radiation yield of about 250 kJ was measured for PegII-25. The purpose of these experiments was to examine the physics of the implosion and relate this physics to the production of the radiation pulse and to provide detailed experimental data which could be compared with 2-D radiation-magnetohydrodynamic (RMHD) simulations. Included in the experimental diagnostic suites were faraday rotation and dB/dt current measurements, a visible framing camera, an x-ray stripline camera, time-dependent spectroscopy, bolometers and XRD`S. A comparison of the results from these experiments shows agreement with 2-D simulation results in the instability development, current, and radiation pulse data, including the pulsewidth, shape, peak power and total radiation yield as measured by bolometry. Instabilities dominate the behavior of the implosion and largely determine the properties of the resulting radiation pulse. The 2-D simulations can be seen to be an important tool in understanding the implosion physics.

  14. NASA Space Radiation Transport Code Development Consortium.

    PubMed

    Townsend, Lawrence W

    2005-01-01

    Recently, NASA established a consortium involving the University of Tennessee (lead institution), the University of Houston, Roanoke College and various government and national laboratories, to accelerate the development of a standard set of radiation transport computer codes for NASA human exploration applications. This effort involves further improvements of the Monte Carlo codes HETC and FLUKA and the deterministic code HZETRN, including developing nuclear reaction databases necessary to extend the Monte Carlo codes to carry out heavy ion transport, and extending HZETRN to three dimensions. The improved codes will be validated by comparing predictions with measured laboratory transport data, provided by an experimental measurements consortium, and measurements in the upper atmosphere on the balloon-borne Deep Space Test Bed (DSTB). In this paper, we present an overview of the consortium members and the current status and future plans of consortium efforts to meet the research goals and objectives of this extensive undertaking.

  15. A Radiative Transport Model for Blazars

    NASA Astrophysics Data System (ADS)

    Lewis, Tiffany; Justin, Finke; Becker, Peter A.

    2017-01-01

    Blazars are observed across the electromagnetic spectrum, often with strong variability throughout. The underlying electron distribution associated with the observed emission is typically not computed from first principles. We start from first-principles to build up a transport model, whose solution is the electron distribution, rather than assuming a convenient functional form. Our analytical transport model considers shock acceleration, adiabatic expansion, stochastic acceleration, Bohm diffusion, and synchrotron radiation. We use this solution to generate predictions for the X-ray spectrum and time lags, and compare the results with data products from BeppoSAX observations of X-ray flares from Mrk 421. This new self-consistent model provides an unprecedented view into the jet physics at play in this source, especially the strength of the shock and stochastic acceleration components and the size of the acceleration region.More recently, we augmented the transport model to incorporate Compton scattering, including Klein-Nishina effects. In this case, an analytical solution cannot be derived, and therefore we obtain the steady-state electron distribution computationally. We compare the resulting radiation spectrum with multi-wavelength data for 3C 279. We show that our new Compton + synchrotron blazar model is the first to successfully fit the FermiLAT gamma-ray data for this source based on a first-principles physical calculation.

  16. A Radiative Transport Model for Blazars

    NASA Astrophysics Data System (ADS)

    Lewis, Tiffany; Finke, Justin; Becker, Peter

    2017-01-01

    Blazars are observed across the electromagnetic spectrum, often with strong variability throughout. We start from first-principles to build up a transport model, whose solution is the electron distribution, rather than assuming a convenient functional form. Our analytical transport model considers shock acceleration, adiabatic expansion, stochastic acceleration, Bohm diffusion, and synchrotron radiation. We use this solution to give predictions for the X-ray spectrum and time lags, comparing the results with BeppoSAX observations of X-ray flares from Mrk 421. This new self-consistent model provides an unprecedented view into the jet physics at play in this source, especially the strength of the shock and stochastic acceleration components and the size of the acceleration region. More recently, we augmented the transport model to incorporate Compton scattering, including Klein-Nishina effects. Here, an analytical solution cannot be derived. Therefore we obtain the steady-state electron distribution computationally. We compare the resulting radiation spectrum with multi-wavelength data for 3C 279. We show that our new Compton + synchrotron blazar model is the first to successfully fit the FermiLAT gamma-ray data for this source based on a first-principles physical calculation.

  17. Transport methods and interactions for space radiations

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Townsend, Lawrence W.; Schimmerling, Walter S.; Khandelwal, Govind S.; Khan, Ferdous S.; Nealy, John E.; Cucinotta, Francis A.; Simonsen, Lisa C.; Shinn, Judy L.; Norbury, John W.

    1991-01-01

    A review of the program in space radiation protection at the Langley Research Center is given. The relevant Boltzmann equations are given with a discussion of approximation procedures for space applications. The interaction coefficients are related to solution of the many-body Schroedinger equation with nuclear and electromagnetic forces. Various solution techniques are discussed to obtain relevant interaction cross sections with extensive comparison with experiments. Solution techniques for the Boltzmann equations are discussed in detail. Transport computer code validation is discussed through analytical benchmarking, comparison with other codes, comparison with laboratory experiments and measurements in space. Applications to lunar and Mars missions are discussed.

  18. Effects of Nuclear Interactions in Space Radiation Transport

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Barghouty, A. F.

    2004-01-01

    Space radiation transport codes have been developed to calculate radiation effects behind materials in human missions to the Moon, Mars or beyond. We study how nuclear fragmentation processes affect predictions from such radiation transport codes. In particular, we investigate the effects of fragmentation cross sections at different energies on fluxes, dose and dose-equivalent from galactic cosmic rays behind typical shielding materials.

  19. Effects of Nuclear Interactions in Space Radiation Transport

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Barghouty, A. F.

    2005-01-01

    Space radiation transport codes have been developed to calculate radiation effects behind materials in human mission to the Moon, Mars or beyond. We study how nuclear fragmentation processes affect predictions from such radiation transport codes. In particular, we investigate the effects of fragmentation cross sections at different energies on fluxes, dose and dose-equivalent from galactic cosmic rays behind typical shielding materials.

  20. Rare event simulation in radiation transport

    SciTech Connect

    Kollman, Craig

    1993-10-01

    This dissertation studies methods for estimating extremely small probabilities by Monte Carlo simulation. Problems in radiation transport typically involve estimating very rare events or the expected value of a random variable which is with overwhelming probability equal to zero. These problems often have high dimensional state spaces and irregular geometries so that analytic solutions are not possible. Monte Carlo simulation must be used to estimate the radiation dosage being transported to a particular location. If the area is well shielded the probability of any one particular particle getting through is very small. Because of the large number of particles involved, even a tiny fraction penetrating the shield may represent an unacceptable level of radiation. It therefore becomes critical to be able to accurately estimate this extremely small probability. Importance sampling is a well known technique for improving the efficiency of rare event calculations. Here, a new set of probabilities is used in the simulation runs. The results are multiple by the likelihood ratio between the true and simulated probabilities so as to keep the estimator unbiased. The variance of the resulting estimator is very sensitive to which new set of transition probabilities are chosen. It is shown that a zero variance estimator does exist, but that its computation requires exact knowledge of the solution. A simple random walk with an associated killing model for the scatter of neutrons is introduced. Large deviation results for optimal importance sampling in random walks are extended to the case where killing is present. An adaptive ``learning`` algorithm for implementing importance sampling is given for more general Markov chain models of neutron scatter. For finite state spaces this algorithm is shown to give with probability one, a sequence of estimates converging exponentially fast to the true solution.

  1. THE MCNPX MONTE CARLO RADIATION TRANSPORT CODE

    SciTech Connect

    WATERS, LAURIE S.; MCKINNEY, GREGG W.; DURKEE, JOE W.; FENSIN, MICHAEL L.; JAMES, MICHAEL R.; JOHNS, RUSSELL C.; PELOWITZ, DENISE B.

    2007-01-10

    MCNPX (Monte Carlo N-Particle eXtended) is a general-purpose Monte Carlo radiation transport code with three-dimensional geometry and continuous-energy transport of 34 particles and light ions. It contains flexible source and tally options, interactive graphics, and support for both sequential and multi-processing computer platforms. MCNPX is based on MCNP4B, and has been upgraded to most MCNP5 capabilities. MCNP is a highly stable code tracking neutrons, photons and electrons, and using evaluated nuclear data libraries for low-energy interaction probabilities. MCNPX has extended this base to a comprehensive set of particles and light ions, with heavy ion transport in development. Models have been included to calculate interaction probabilities when libraries are not available. Recent additions focus on the time evolution of residual nuclei decay, allowing calculation of transmutation and delayed particle emission. MCNPX is now a code of great dynamic range, and the excellent neutronics capabilities allow new opportunities to simulate devices of interest to experimental particle physics; particularly calorimetry. This paper describes the capabilities of the current MCNPX version 2.6.C, and also discusses ongoing code development.

  2. Transport of infrared radiation in cuboidal clouds

    NASA Technical Reports Server (NTRS)

    HARSHVARDHAN; Weinman, J. A.; Davies, R.

    1981-01-01

    The transport of infrared radiation in a single cuboidal cloud using a vertical two steam approximation was modeled. The emittance of the top face of the model cloud is always less than that for a plane parallel cloud of the same optical depth. The hemisphere flux escaping from the cloud top has a gradient from the center to the edges which brighten when the cloud is over warmer ground. Cooling rate calculations in the 8 to 13.6 micrometer region show that there is cooling from the sides of the cloud at all levels even when there is heating of the core from the ground below. The radiances exiting from model cuboidal clouds were computed by path integration over the source function obtained with the two stream approximation. It is suggested that the brightness temperature measured from finite clouds will overestimate the cloud top temperature.

  3. Validation of comprehensive space radiation transport code

    SciTech Connect

    Shinn, J.L.; Simonsen, L.C.; Cucinotta, F.A.

    1998-12-01

    The HZETRN code has been developed over the past decade to evaluate the local radiation fields within sensitive materials on spacecraft in the space environment. Most of the more important nuclear and atomic processes are now modeled and evaluation within a complex spacecraft geometry with differing material components, including transition effects across boundaries of dissimilar materials, are included. The atomic/nuclear database and transport procedures have received limited validation in laboratory testing with high energy ion beams. The codes have been applied in design of the SAGE-III instrument resulting in material changes to control injurious neutron production, in the study of the Space Shuttle single event upsets, and in validation with space measurements (particle telescopes, tissue equivalent proportional counters, CR-39) on Shuttle and Mir. The present paper reviews the code development and presents recent results in laboratory and space flight validation.

  4. Space Radiation Transport Code Development: 3DHZETRN

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

    2015-01-01

    The space radiation transport code, HZETRN, has been used extensively for research, vehicle design optimization, risk analysis, and related applications. One of the simplifying features of the HZETRN transport formalism is the straight-ahead approximation, wherein all particles are assumed to travel along a common axis. This reduces the governing equation to one spatial dimension allowing enormous simplification and highly efficient computational procedures to be implemented. Despite the physical simplifications, the HZETRN code is widely used for space applications and has been found to agree well with fully 3D Monte Carlo simulations in many circumstances. Recent work has focused on the development of 3D transport corrections for neutrons and light ions (Z < 2) for which the straight-ahead approximation is known to be less accurate. Within the development of 3D corrections, well-defined convergence criteria have been considered, allowing approximation errors at each stage in model development to be quantified. The present level of development assumes the neutron cross sections have an isotropic component treated within N explicit angular directions and a forward component represented by the straight-ahead approximation. The N = 1 solution refers to the straight-ahead treatment, while N = 2 represents the bi-directional model in current use for engineering design. The figure below shows neutrons, protons, and alphas for various values of N at locations in an aluminum sphere exposed to a solar particle event (SPE) spectrum. The neutron fluence converges quickly in simple geometry with N > 14 directions. The improved code, 3DHZETRN, transports neutrons, light ions, and heavy ions under space-like boundary conditions through general geometry while maintaining a high degree of computational efficiency. A brief overview of the 3D transport formalism for neutrons and light ions is given, and extensive benchmarking results with the Monte Carlo codes Geant4, FLUKA, and

  5. Radiation Transport Tools for Space Applications: A Review

    NASA Technical Reports Server (NTRS)

    Jun, Insoo; Evans, Robin; Cherng, Michael; Kang, Shawn

    2008-01-01

    This slide presentation contains a brief discussion of nuclear transport codes widely used in the space radiation community for shielding and scientific analyses. Seven radiation transport codes that are addressed. The two general methods (i.e., Monte Carlo Method, and the Deterministic Method) are briefly reviewed.

  6. Los Alamos National Laboratory.

    ERIC Educational Resources Information Center

    Hammel, Edward F., Jr.

    1982-01-01

    Current and post World War II scientific research at the Los Alamos National Laboratory (New Mexico) is discussed. The operation of the laboratory, the Los Alamos consultant program, and continuation education, and continuing education activities at the laboratory are also discussed. (JN)

  7. Description of Transport Codes for Space Radiation Shielding

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Wilson, John W.; Cucinotta, Francis A.

    2011-01-01

    This slide presentation describes transport codes and their use for studying and designing space radiation shielding. When combined with risk projection models radiation transport codes serve as the main tool for study radiation and designing shielding. There are three criteria for assessing the accuracy of transport codes: (1) Ground-based studies with defined beams and material layouts, (2) Inter-comparison of transport code results for matched boundary conditions and (3) Comparisons to flight measurements. These three criteria have a very high degree with NASA's HZETRN/QMSFRG.

  8. Transport of infrared radiation in cuboidal clouds

    NASA Technical Reports Server (NTRS)

    Harshvardhan, MR.; Weinman, J. A.; Davies, R.

    1981-01-01

    The transport of infrared radiation in a single cuboidal cloud is modeled using a variable azimuth two-stream approximation. Computations are made at 10 microns for a Deirmendjian (1969) C-1 water cloud where the single scattering albedo is equal to 0.638 and the asymmetry parameter is 0.865. The results indicate that the emittance of the top face of the model cloud is always less than that for a plane parallel cloud of the same optical depth. The hemispheric flux escaping from the cloud top possesses a gradient from the center to the edges which are warmer when the cloud is over warmer ground. Cooling rate calculations in the 8-13.6 micron region demonstrate that there is cooling out of the sides of the cloud at all levels even when there is heating of the core from the ground below. The radiances exiting from model cuboidal clouds are computed by path integration over the source function obtained with the two-stream approximation. Results indicate that the brightness temperature measured from finite clouds will overestimate the cloud-top temperature.

  9. Simulations of Groundwater Flow and Radionuclide Transport in the Vadose and Saturated Zones beneath Area G, Los Alamos National Laboratory

    SciTech Connect

    Kay H. Birdsell; Kathleen M. Bower; Andrew V. Wolfsberg; Wendy E. Soll; Terry A. Cherry; Tade W. Orr

    1999-07-01

    Numerical simulations are used to predict the migration of radionuclides from the disposal units at Material Disposal Area G through the vadose zone and into the main aquifer in support of a radiological performance assessment and composite analysis for the site. The calculations are performed with the finite element code, FEHM. The transport of nuclides through the vadose zone is computed using a three-dimensional model that describes the complex mesa top geology of the site. The model incorporates the positions and inventories of thirty-four disposal pits and four shaft fields located at Area G as well as those of proposed future pits and shafts. Only three nuclides, C-14, Tc-99, and I-129, proved to be of concern for the groundwater pathway over a 10,000-year period. The spatial and temporal flux of these three nuclides from the vadose zone is applied as a source term for the three-dimensional saturated zone model of the main aquifer that underlies the site. The movement of these nuclides in the aquifer to a downstream location is calculated, and aquifer concentrations are converted to doses. Doses related to aquifer concentrations are six or more orders of magnitude lower than allowable Department of Energy performance objectives for low-level radioactive waste sites. Numerical studies were used to better understand vadose-zone flow through the dry mesa-top environment at Area G. These studies helped define the final model used to model flow and transport through the vadose zone. The study of transient percolation indicates that a steady flow vadose-zone model is adequate for computing contaminant flux to the aquifer. The fracture flow studies and the investigation of the effect of basalt and pumice properties helped us define appropriate hydrologic properties for the modeling. Finally, the evaporation study helped to justify low infiltration rates.

  10. Stockpile Stewardship: Los Alamos

    ScienceCinema

    McMillan, Charlie; Morgan, Nathanial; Goorley, Tom; Merrill, Frank; Funk, Dave; Korzekwa, Deniece; Laintz, Ken

    2016-07-12

    "Heritage of Science" is a short video that highlights the Stockpile Stewardship program at Los Alamos National Laboratory. Stockpile Stewardship was conceived in the early 1990s as a national science-based program that could assure the safety, security, and effectiveness of the U.S. nuclear deterrent without the need for full-scale underground nuclear testing. This video was produced by Los Alamos National Laboratory for screening at the Lab's Bradbury Science Museum in Los Alamos, NM and is narrated by science correspondent Miles O'Brien.

  11. Radiation transport within oceanic (case 1) water

    NASA Astrophysics Data System (ADS)

    Morel, André; Gentili, Bernard

    2004-06-01

    A spectral model of the inherent optical properties (IOP) of oceanic case 1 waters, as previously developed for studying the near-surface bidirectional reflectance, provides the input parameters for the present computations of radiative transport (RT), now extended throughout the water column (three times the euphotic zone). All spectral apparent optical properties (AOP) are computed at each of the levels (30) for six chlorophyll values (from 0.03 to 10 mg m-3) and for six values of the zenith Sun angle (from 0° to 75°). The Raman emission is accounted for. From the irradiances and radiances values the various attenuation coefficients (K), the average cosines (?), and the reflectance (R) are derived for all depths and layers. Their variations resulting from the Sun's position are also studied, which removes the static character of previous empirical models inasmuch as the diurnal changes of the parameters describing the in-water light field can be predicted. The AOPs observed within the deepest levels are also compared to values independently derived from an asymptotic (iterative) solution of the RT. The rate of approach to the asymptotic regime is numerically analyzed; this rate is actually governed by τb, i.e., this fraction of τ (the optical thickness) that corresponds only to scattering. Practical applications of these systematic computations are examined, such as the change (with solar position) of the euphotic depth, the time- and wavelength-dependent scalar irradiance that controls during the day the energy available for photosynthesis (or the heating rate), and the interpretation of radiometric field experiments involving upward and downward irradiance measurements. Some approximate expressions relating AOPs to IOPs are examined in the light of exact computations.

  12. Implict Monte Carlo Radiation Transport Simulations of Four Test Problems

    SciTech Connect

    Gentile, N

    2007-08-01

    Radiation transport codes, like almost all codes, are difficult to develop and debug. It is helpful to have small, easy to run test problems with known answers to use in development and debugging. It is also prudent to re-run test problems periodically during development to ensure that previous code capabilities have not been lost. We describe four radiation transport test problems with analytic or approximate analytic answers. These test problems are suitable for use in debugging and testing radiation transport codes. We also give results of simulations of these test problems performed with an Implicit Monte Carlo photonics code.

  13. Effects of Nuclear Interactions on Accuracy of Space Radiation Transport

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Barghouty, A. F.

    2005-01-01

    Space radiation risk to astronauts and electronic equipments is one major obstacle in long term human space explorations. Space radiation transport codes have been developed to calculate radiation effects behind materials in human missions to the Moon, Mars or beyond. We study how nuclear fragmentation processes affect the accuracy of predictions from such radiation transport. In particular, we investigate the effects of fragmentation cross sections at different energies on fluxes, dose and dose-equivalent from galactic cosmic rays behind typical shielding materials. These results tell us at what energies nuclear cross sections are the most important for radiation risk evaluations, and how uncertainties in our knowledge about nuclear fragmentations relate to uncertainties in space transport predictions.

  14. Ionizing radiation, ion transports, and radioresistance of cancer cells

    PubMed Central

    Huber, Stephan M.; Butz, Lena; Stegen, Benjamin; Klumpp, Dominik; Braun, Norbert; Ruth, Peter; Eckert, Franziska

    2013-01-01

    The standard treatment of many tumor entities comprises fractionated radiation therapy which applies ionizing radiation to the tumor-bearing target volume. Ionizing radiation causes double-strand breaks in the DNA backbone that result in cell death if the number of DNA double-strand breaks exceeds the DNA repair capacity of the tumor cell. Ionizing radiation reportedly does not only act on the DNA in the nucleus but also on the plasma membrane. In particular, ionizing radiation-induced modifications of ion channels and transporters have been reported. Importantly, these altered transports seem to contribute to the survival of the irradiated tumor cells. The present review article summarizes our current knowledge on the underlying mechanisms and introduces strategies to radiosensitize tumor cells by targeting plasma membrane ion transports. PMID:23966948

  15. Near-field radiative thermal transport: From theory to experiment

    SciTech Connect

    Song, Bai Fiorino, Anthony; Meyhofer, Edgar; Reddy, Pramod

    2015-05-15

    Radiative thermal transport via the fluctuating electromagnetic near-field has recently attracted increasing attention due to its fundamental importance and its impact on a range of applications from data storage to thermal management and energy conversion. After a brief historical account of radiative thermal transport, we summarize the basics of fluctuational electrodynamics, a theoretical framework for the study of radiative heat transfer in terms of thermally excited propagating and evanescent electromagnetic waves. Various approaches to modeling near-field thermal transport are briefly discussed, together with key results and proposals for manipulation and utilization of radiative heat flow. Subsequently, we review the experimental advances in the characterization of both near-field heat flow and energy density. We conclude with remarks on the opportunities and challenges for future explorations of radiative heat transfer at the nanoscale.

  16. ANALYSIS OF A NUMERICAL SOLVER FOR RADIATIVE TRANSPORT EQUATION.

    PubMed

    Gao, Hao; Zhao, Hongkai

    2013-01-01

    We analyze a numerical algorithm for solving radiative transport equation with vacuum or reflection boundary condition that was proposed in [4] with angular discretization by finite element method and spatial discretization by discontinuous Galerkin or finite difference method.

  17. Path Toward a Unifid Geometry for Radiation Transport

    NASA Technical Reports Server (NTRS)

    Lee, Kerry; Barzilla, Janet; Davis, Andrew; Zachmann

    2014-01-01

    The Direct Accelerated Geometry for Radiation Analysis and Design (DAGRAD) element of the RadWorks Project under Advanced Exploration Systems (AES) within the Space Technology Mission Directorate (STMD) of NASA will enable new designs and concepts of operation for radiation risk assessment, mitigation and protection. This element is designed to produce a solution that will allow NASA to calculate the transport of space radiation through complex computer-aided design (CAD) models using the state-of-the-art analytic and Monte Carlo radiation transport codes. Due to the inherent hazard of astronaut and spacecraft exposure to ionizing radiation in low-Earth orbit (LEO) or in deep space, risk analyses must be performed for all crew vehicles and habitats. Incorporating these analyses into the design process can minimize the mass needed solely for radiation protection. Transport of the radiation fields as they pass through shielding and body materials can be simulated using Monte Carlo techniques or described by the Boltzmann equation, which is obtained by balancing changes in particle fluxes as they traverse a small volume of material with the gains and losses caused by atomic and nuclear collisions. Deterministic codes that solve the Boltzmann transport equation, such as HZETRN [high charge and energy transport code developed by NASA Langley Research Center (LaRC)], are generally computationally faster than Monte Carlo codes such as FLUKA, GEANT4, MCNP(X) or PHITS; however, they are currently limited to transport in one dimension, which poorly represents the secondary light ion and neutron radiation fields. NASA currently uses HZETRN space radiation transport software, both because it is computationally efficient and because proven methods have been developed for using this software to analyze complex geometries. Although Monte Carlo codes describe the relevant physics in a fully three-dimensional manner, their computational costs have thus far prevented their

  18. Path Toward a Unified Geometry for Radiation Transport

    NASA Astrophysics Data System (ADS)

    Lee, Kerry

    The Direct Accelerated Geometry for Radiation Analysis and Design (DAGRAD) element of the RadWorks Project under Advanced Exploration Systems (AES) within the Space Technology Mission Directorate (STMD) of NASA will enable new designs and concepts of operation for radiation risk assessment, mitigation and protection. This element is designed to produce a solution that will allow NASA to calculate the transport of space radiation through complex CAD models using the state-of-the-art analytic and Monte Carlo radiation transport codes. Due to the inherent hazard of astronaut and spacecraft exposure to ionizing radiation in low-Earth orbit (LEO) or in deep space, risk analyses must be performed for all crew vehicles and habitats. Incorporating these analyses into the design process can minimize the mass needed solely for radiation protection. Transport of the radiation fields as they pass through shielding and body materials can be simulated using Monte Carlo techniques or described by the Boltzmann equation, which is obtained by balancing changes in particle fluxes as they traverse a small volume of material with the gains and losses caused by atomic and nuclear collisions. Deterministic codes that solve the Boltzmann transport equation, such as HZETRN (high charge and energy transport code developed by NASA LaRC), are generally computationally faster than Monte Carlo codes such as FLUKA, GEANT4, MCNP(X) or PHITS; however, they are currently limited to transport in one dimension, which poorly represents the secondary light ion and neutron radiation fields. NASA currently uses HZETRN space radiation transport software, both because it is computationally efficient and because proven methods have been developed for using this software to analyze complex geometries. Although Monte Carlo codes describe the relevant physics in a fully three-dimensional manner, their computational costs have thus far prevented their widespread use for analysis of complex CAD models, leading

  19. Radial transport in the Earth's radiation belts (Invited)

    NASA Astrophysics Data System (ADS)

    Kress, B. T.; Ukhorskiy, A. Y.; Hudson, M. K.

    2010-12-01

    For over forty years the standard approach to modeling the dynamics of the Earth's radiation belts has been based on a diffusion equation, which can be derived from the Vlasov equation using a quasilinear approximation. The radiation belt diffusion equation describes the evolution of a particle distribution function in a space of one or several of the three adiabatic invariants associated with the motions of a charged particle in a dipole magnetic field. Increasingly, observations and theoretical studies suggest that fully nonlinear transport, not modeled by quasilinear diffusion, plays an important role in radiation belt dynamics, e.g., the shock-drift mechanism modeled by Li et al. [1993]. This presentation will focus on radiation belt particle transport across magnetic L-shells (loosely called radial transport). Radial transport is thought to be one of the primary drivers of radiation belt dynamics. A comprehensive review of the known mechanisms of radial transport and some of their effects will be given, including those that can be modeled with a diffusion equation and those requiring a fully nonlinear treatment. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake, (1993), Simulations of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, Geophys. Res. Lett., 20, 2423.

  20. Improved geometry representations for Monte Carlo radiation transport.

    SciTech Connect

    Martin, Matthew Ryan

    2004-08-01

    ITS (Integrated Tiger Series) permits a state-of-the-art Monte Carlo solution of linear time-integrated coupled electron/photon radiation transport problems with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. ITS allows designers to predict product performance in radiation environments.

  1. Nonrelativistic grey S n -transport radiative-shock solutions

    DOE PAGES

    Ferguson, J. M.; Morel, J. E.; Lowrie, R. B.

    2017-06-01

    We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that thismore » monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.« less

  2. Nonrelativistic radiative shock solutions with grey Sn-transport

    DOE PAGES

    Ferguson, Jim Michael; Morel, Jim Emanuel; Lowrie, Robert Byron

    2017-02-24

    We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that thismore » monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.« less

  3. Modeling Aeolian Transport of Contaminated Sediments at Los Alamos National Laboratory, Technical Area 54, Area G: Sensitivities to Succession, Disturbance, and Future Climate

    SciTech Connect

    Whicker, Jeffrey J.; Kirchner, Thomas B.; Breshears, David D.; Field, Jason P.

    2012-03-27

    The Technical Area 54 (TA-54) Area G disposal facility is used for the disposal of radioactive waste at Los Alamos National Laboratory (LANL). U.S. Department of Energy (DOE) Order 435.1 (DOE, 2001) requires that radioactive waste be managed in a manner that protects public health and safety and the environment. In compliance with that requirement, DOE field sites must prepare and maintain site-specific radiological performance assessments for facilities that receive waste after September 26, 1988. Sites are also required to conduct composite analyses for facilities that receive waste after this date; these analyses account for the cumulative impacts of all waste that has been (and will be) disposed of at the facilities and other sources of radioactive material that may interact with these facilities. LANL issued Revision 4 of the Area G performance assessment and composite analysis in 2008. In support of those analyses, vertical and horizontal sediment flux data were collected at two analog sites, each with different dominant vegetation characteristics, and used to estimate rates of vertical resuspension and wind erosion for Area G. The results of that investigation indicated that there was no net loss of soil at the disposal site due to wind erosion, and suggested minimal impacts of wind on the long-term performance of the facility. However, that study did not evaluate the potential for contaminant transport caused by the horizontal movement of soil particles over long time frames. Since that time, additional field data have been collected to estimate wind threshold velocities for initiating sediment transport due to saltation and rates of sediment transport once those thresholds are reached. Data such as these have been used in the development of the Vegetation Modified Transport (VMTran) model. This model is designed to estimate patterns and long-term rates of contaminant redistribution caused by winds at the site, taking into account the impacts of plant

  4. TORUS: Radiation transport and hydrodynamics code

    NASA Astrophysics Data System (ADS)

    Harries, Tim

    2014-04-01

    TORUS is a flexible radiation transfer and radiation-hydrodynamics code. The code has a basic infrastructure that includes the AMR mesh scheme that is used by several physics modules including atomic line transfer in a moving medium, molecular line transfer, photoionization, radiation hydrodynamics and radiative equilibrium. TORUS is useful for a variety of problems, including magnetospheric accretion onto T Tauri stars, spiral nebulae around Wolf-Rayet stars, discs around Herbig AeBe stars, structured winds of O supergiants and Raman-scattered line formation in symbiotic binaries, and dust emission and molecular line formation in star forming clusters. The code is written in Fortran 2003 and is compiled using a standard Gnu makefile. The code is parallelized using both MPI and OMP, and can use these parallel sections either separately or in a hybrid mode.

  5. Relativistic radiation transport in dispersive media

    SciTech Connect

    Kichenassamy, S.; Krikorian, R.A.

    1985-10-15

    A general-relativistic radiative transfer equation in an isotropic, weakly absorbing, nonmagnetized dispersive medium is derived using the kinetic-theoretical approach and the relativistic Hamiltonian theory of geometrical optics in those media. It yields the generally accepted classical equation in the special-relativistic approximation and in stationary conditions. The influence of the gravitational field and of space-time variations of the refractive index n on the radiation distribution is made explicit in the case of spherical symmetry.

  6. Radiation transport Part B: Applications with examples

    SciTech Connect

    Beutler, D.E.

    1997-06-01

    In the previous sections Len Lorence has described the need, theory, and types of radiation codes that can be applied to model the results of radiation effects tests or working environments for electronics. For the rest of this segment, the author will concentrate on the specific ways the codes can be used to predict device response or analyze radiation test results. Regardless of whether one is predicting responses in a working or test environment, the procedures are virtually the same. The same can be said for the use of 1-, 2-, or 3-dimensional codes and Monte Carlo or discrete ordinates codes. No attempt is made to instruct the student on the specifics of the code. For example, the author will not discuss the details, such as the number of meshes, energy groups, etc. that are appropriate for a discrete ordinates code. For the sake of simplicity, he will restrict himself to the 1-dimensional code CEPXS/ONELD. This code along with a wide variety of other radiation codes can be obtained form the Radiation Safety Information Computational Center (RSICC) for a nominal handling fee.

  7. Los Alamos offers Fellowships

    NASA Astrophysics Data System (ADS)

    Los Alamos National Laboratory in New Mexico is calling for applications for postdoctoral appointments and research fellowships. The positions are available in geoscience as well as other scientific disciplines.The laboratory, which is operated by the University of California for the Department of Energy, awards J. Robert Oppenheimer Research Fellowships to scientists that either have or will soon complete doctoral degrees. The appointments are for two years, are renewable for a third year, and carry a stipend of $51,865 per year. Potential applicants should send a resume or employment application and a statement of research goals to Carol M. Rich, Div. 89, Human Resources Development Division, MS P290, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 by mid-November.

  8. Comparison of Space Radiation Calculations from Deterministic and Monte Carlo Transport Codes

    NASA Technical Reports Server (NTRS)

    Adams, J. H.; Lin, Z. W.; Nasser, A. F.; Randeniya, S.; Tripathi, r. K.; Watts, J. W.; Yepes, P.

    2010-01-01

    The presentation outline includes motivation, radiation transport codes being considered, space radiation cases being considered, results for slab geometry, results from spherical geometry, and summary. ///////// main physics in radiation transport codes hzetrn uprop fluka geant4, slab geometry, spe, gcr,

  9. bhlight: GENERAL RELATIVISTIC RADIATION MAGNETOHYDRODYNAMICS WITH MONTE CARLO TRANSPORT

    SciTech Connect

    Ryan, B. R.; Gammie, C. F.; Dolence, J. C.

    2015-07-01

    We present bhlight, a numerical scheme for solving the equations of general relativistic radiation magnetohydrodynamics using a direct Monte Carlo solution of the frequency-dependent radiative transport equation. bhlight is designed to evolve black hole accretion flows at intermediate accretion rate, in the regime between the classical radiatively efficient disk and the radiatively inefficient accretion flow (RIAF), in which global radiative effects play a sub-dominant but non-negligible role in disk dynamics. We describe the governing equations, numerical method, idiosyncrasies of our implementation, and a suite of test and convergence results. We also describe example applications to radiative Bondi accretion and to a slowly accreting Kerr black hole in axisymmetry.

  10. bhlight: General Relativistic Radiation Magnetohydrodynamics with Monte Carlo Transport

    DOE PAGES

    Ryan, Benjamin R; Dolence, Joshua C.; Gammie, Charles F.

    2015-06-25

    We present bhlight, a numerical scheme for solving the equations of general relativistic radiation magnetohydrodynamics using a direct Monte Carlo solution of the frequency-dependent radiative transport equation. bhlight is designed to evolve black hole accretion flows at intermediate accretion rate, in the regime between the classical radiatively efficient disk and the radiatively inefficient accretion flow (RIAF), in which global radiative effects play a sub-dominant but non-negligible role in disk dynamics. We describe the governing equations, numerical method, idiosyncrasies of our implementation, and a suite of test and convergence results. We also describe example applications to radiative Bondi accretion and tomore » a slowly accreting Kerr black hole in axisymmetry.« less

  11. bhlight: General Relativistic Radiation Magnetohydrodynamics with Monte Carlo Transport

    SciTech Connect

    Ryan, Benjamin R; Dolence, Joshua C.; Gammie, Charles F.

    2015-06-25

    We present bhlight, a numerical scheme for solving the equations of general relativistic radiation magnetohydrodynamics using a direct Monte Carlo solution of the frequency-dependent radiative transport equation. bhlight is designed to evolve black hole accretion flows at intermediate accretion rate, in the regime between the classical radiatively efficient disk and the radiatively inefficient accretion flow (RIAF), in which global radiative effects play a sub-dominant but non-negligible role in disk dynamics. We describe the governing equations, numerical method, idiosyncrasies of our implementation, and a suite of test and convergence results. We also describe example applications to radiative Bondi accretion and to a slowly accreting Kerr black hole in axisymmetry.

  12. Transporting Radioactive Material | Radiation Protection | US ...

    EPA Pesticide Factsheets

    2016-09-07

    Radioactive material can be transported by truck, train, plane or ship. The shipment of radioactive material has been regulated since 1939. Shipping routes for radioactive materials are picked very carefully and shipments are tracked. Markings on containers and vehicles explain the contents of each package using standard terms and codes.

  13. Mixed singular-regular boundary conditions in multislab radiation transport

    NASA Astrophysics Data System (ADS)

    de Abreu, Marcos Pimenta

    2004-06-01

    This article reports a computational method for approximately solving radiation transport problems with anisotropic scattering defined on multislab domains irradiated from one side with a beam of monoenergetic neutral particles. We assume here that the incident beam may have a monodirectional component and a continuously distributed component in angle. We begin by defining the target problem representing the class of radiation transport problems that we are focused on. We then Chandrasekhar decompose the target problem into an uncollided transport problem with left singular boundary conditions and a diffusive transport problem with regular boundary conditions. We perform an analysis of these problems to derive the exact solution of the uncollided transport problem and a discrete ordinates solution in open form to the diffusive transport problem. These solutions are the basis for the definition of a computational method for approximately solving the target problem. We illustrate the numerical accuracy of our method with three basic problems in radiative transfer and neutron transport, and we conclude this article with a discussion and directions for future work.

  14. Accounting for correlated errors in inverse radiation transport problems.

    SciTech Connect

    Mattingly, John K.; Stork, Christopher Lyle; Thomas, Edward Victor

    2010-11-01

    Inverse radiation transport focuses on identifying the configuration of an unknown radiation source given its observed radiation signatures. The inverse problem is solved by finding the set of transport model variables that minimizes a weighted sum of the squared differences by channel between the observed signature and the signature predicted by the hypothesized model parameters. The weights per channel are inversely proportional to the sum of the variances of the measurement and model errors at a given channel. In the current treatment, the implicit assumption is that the errors (differences between the modeled and observed radiation signatures) are independent across channels. In this paper, an alternative method that accounts for correlated errors between channels is described and illustrated for inverse problems based on gamma spectroscopy.

  15. The essential linearity of thermal radiation net transport

    NASA Astrophysics Data System (ADS)

    Barker, J. J.

    1991-06-01

    Thermal radiation net transport is proportional to the difference in the fourth powers of the absolute temperatures of the radiator and the receiver. During a study of heat transfer mechanisms in the underground storage tanks for the radioactive wastes at the Hanford Site in Washington, it was discovered that the fourth power difference is approximated by a linear function of the temperature difference between the radiator and the receiver, with astounding fidelity. This linearity makes satisfying boundary conditions for analytical and numerical calculations much simpler and simplifies comparisons with other modes of heat transfer. The paper derives the relationship and illustrates its use by demonstrating that radiation transports more heat through the air space in the tank than does natural convection.

  16. The Los Alamos primer

    SciTech Connect

    Serber, R.

    1992-01-01

    This book contains the 1943 lecture notes of Robert Serber. Serber was a protege of J. Robert Oppenheimer and member of the team that built the first atomic bomb - reveal what the Los Alamos scientists knew, and did not know, about the terrifying weapon they were building.

  17. Measurement of the radiative transport properties of reticulated alumina foams

    SciTech Connect

    Hale, M.J.; Bohn, M.S.

    1992-12-01

    This paper presents a method for determining radiative transport properties of reticulated materials. The method has both experimental and analytical components. A polar nephelometer is used to measure the scattering profile of a sample of the reticulated material. The results of a Monte Carlo simulation of the experiment are then combined with the experimental results to give the scatter albedo and extinction coefficient. This paper presents the results of using this method to determine the radiative transport properties of four different porosities (10, 20, 30, 65 pores per inch) of cylindrical reticulated alumina samples ranging in thickness form 0.5 inches to 2. 5 inches.

  18. Cosmic radiation exposure in subsonic air transport

    NASA Technical Reports Server (NTRS)

    Wallace, R. W.; Sondhaus, C. A.

    1978-01-01

    Data derived from 1973 statistics on 2.99 million intercity flights carrying 468 million seats were included in the calculations, yielding a total of 581 billion seat-kilometer. The average flight was 1,084 km in length, was flown at an altitude of 9.47 km, and lasted 1.41 h. The average dose rate was 0.20 mrem/h, resulting in an average passenger dose of 2.82 mrem/year and an average crewmember dose of 160 mrem/year. The average radiation dose to the total U.S. population was 0.47 mrem/person/year. These results are in good agreement with data from several experiments performed by us and others in aircraft at various altitudes and latitudes. The significance of these doses to the population is discussed.

  19. Discontinuous Galerkin Methods for Neutrino Radiation Transport

    NASA Astrophysics Data System (ADS)

    Endeve, Eirik; Hauck, Cory; Xing, Yulong; Mezzacappa, Anthony

    2015-04-01

    We are developing new computational methods for simulation of neutrino transport in core-collapse supernovae, which is challenging since neutrinos evolve from being diffusive in the proto-neutron star to nearly free streaming in the critical neutrino heating region. To this end, we consider conservative formulations of the Boltzmann equation, and aim to develop robust, high-order accurate methods. Runge-Kutta discontinuous Galerkin (DG) methods, offer several attractive properties, including (i) high-order accuracy on a compact stencil and (ii) correct asymptotic behavior in the diffusion limit. We have recently developed a new DG method for the advection part for the transport solve, which is high-order accurate and strictly preserves the physical bounds of the distribution function; i.e., f ∈ [ 0 , 1 ] . We summarize the main ingredients of our bound-preserving DG method and discuss ongoing work to include neutrino-matter interactions in the scheme. Research sponsored in part by Oak Ridge National Laboratory, managed by UT-Battelle, LLC for the U. S. Department of Energy

  20. Diagnosing ocean energy transports from earth radiation budget measurements

    NASA Technical Reports Server (NTRS)

    Sohn, Byung-Ju; Smith, Eric A.

    1992-01-01

    The maximum energy production (MEP) principle suggested by Paltridge (1975) is applied to separate the satellite-inferred required total transports into the atmospheric and the oceanic components within a two-dimensional (2D) framework. For this purpose, the required 2D energy transports (Sohn and Smith, 1991) are imposed on Paltridge's energy balance model which is then solved as a variational problem. The results provide separated atmospheric and oceanic transports on a 2D basis such that the total divergence is equal to the net radiation measured from a satellite.

  1. A space radiation transport method development.

    PubMed

    Wilson, J W; Tripathi, R K; Qualls, G D; Cucinotta, F A; Prael, R E; Norbury, J W; Heinbockel, J H; Tweed, J

    2004-01-01

    Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest-order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard finite element method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 ms and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of re-configurable computing and could be utilized in the final design as verification of the deterministic method optimized design.

  2. A space radiation transport method development

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Tripathi, R. K.; Qualls, G. D.; Cucinotta, F. A.; Prael, R. E.; Norbury, J. W.; Heinbockel, J. H.; Tweed, J.

    2004-01-01

    Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest-order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard finite element method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 ms and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of re-configurable computing and could be utilized in the final design as verification of the deterministic method optimized design. Published by Elsevier Ltd on behalf of COSPAR.

  3. Instabilities and the transport of polarized astrophysical maser radiation

    NASA Technical Reports Server (NTRS)

    Wallin, Bradley K.; Watson, William D.

    1995-01-01

    Time-dependent, radiative instabilities in the creation and transport of polarized astrophysical maser radiation in the presence of a magnetic field are calculated. The instabilities are similar to and occur under the same conditions as those found previously by Scappaticci & Watson for unpolarized maser radiation. The common limits in which the Zeeman splitting is much greater than, and much less than, the spectral line breadths are both considered in the current investigation. The resulting fluctuations in the emergent radiation are potentially relevant for the OH 1665 MHz masers which have been reported to fluctuate on timescales of 1000 s and which tend to be polarized. Instabilities occur and alter the transport of maser radiation only under a quite limited range of conditions. In particular, we find here that the instabilities do not occur for conditions that are appropriate for astrophysical masers with small Zeeman splittings such as the SiO and H2O masers. The time-independent, numerical solutions to the GKK equations of radiative transfer that have been obtained in previous investigations are thus essentially always valid except within a narrow range of conditions relevant for the OH masers.

  4. Radiation Belt Transport Driven by Solar Wind Dynamic Pressure Fluctuations

    NASA Astrophysics Data System (ADS)

    Kress, B. T.; Hudson, M. K.; Ukhorskiy, A. Y.; Mueller, H.

    2012-12-01

    The creation of the Earth's outer zone radiation belts is attributed to earthward transport and adiabatic acceleration of electrons by drift-resonant interactions with electromagnetic fluctuations in the magnetosphere. Three types of radial transport driven by solar wind dynamic pressure fluctuations that have been identified are: (1) radial diffusion [Falthammer, 1965], (2) significant changes in the phase space density radial profile due to a single or few ULF drift-resonant interactions [Ukhorskiy et al., 2006; Degeling et al., 2008], and (3) shock associated injections of radiation belt electrons occurring in less than a drift period [Li et al., 1993]. A progress report will be given on work to fully characterize different forms of radial transport and their effect on the Earth's radiation belts. The work is being carried out by computing test-particle trajectories in electric and magnetic fields from a simple analytic ULF field model and from global MHD simulations of the magnetosphere. Degeling, A. W., L. G. Ozeke, R. Rankin, I. R. Mann, and K. Kabin (2008), Drift resonant generation of peaked relativistic electron distributions by Pc 5 ULF waves, textit{J. Geophys. Res., 113}, A02208, doi:10.1029/2007JA012411. Fälthammar, C.-G. (1965), Effects of Time-Dependent Electric Fields on Geomagnetically Trapped Radiation, J. Geophys. Res., 70(11), 2503-2516, doi:10.1029/JZ070i011p02503. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake (1993), Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, textit{Geophys. Res. Lett., 20}(22), 2423-2426, doi:10.1029/93GL02701. Ukhorskiy, A. Y., B. J. Anderson, K. Takahashi, and N. A. Tsyganenko (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, textit{Geophys. Res. Lett., 33}(6), L06111, doi:10.1029/2005GL024380.

  5. Dosimetry at the Los Alamos Critical Experiments Facility: Past, present, and future

    SciTech Connect

    Malenfant, R.E.

    1993-10-01

    Although the primary reason for the existence of the Los Alamos Critical Experiments Facility is to provide basic data on the physics of systems of fissile material, the physical arrangements and ability to provide sources of radiation have led to applications for all types of radiation dosimetry. In the broad definition of radiation phenomena, the facility has provided sources to evaluate biological effects, radiation shielding and transport, and measurements of basic parameters such as the evaluation of delayed neutron parameters. Within the last 15 years, many of the radiation measurements have been directed to calibration and intercomparison of dosimetry related to nuclear criticality safety. Future plans include (1) the new applications of Godiva IV, a bare-metal pulse assembly, for dosimetry (including an evaluation of neutron and gamma-ray room return); (2) a proposal to relocate the Health Physics Research Reactor from the Oak Ridge National Laboratory to Los Alamos, which will provide the opportunity to continue the application of a primary benchmark source to radiation dosimetry; and (3) a proposal to employ SHEBA, a low-enrichment solution assembly, for accident dosimetry and evaluation.

  6. Los Alamos Programming Models

    SciTech Connect

    Bergen, Benjamin Karl

    2016-07-07

    This is the PDF of a powerpoint presentation from a teleconference on Los Alamos programming models. It starts by listing their assumptions for the programming models and then details a hierarchical programming model at the System Level and Node Level. Then it details how to map this to their internal nomenclature. Finally, a list is given of what they are currently doing in this regard.

  7. Radiation-induced reductions in transporter mRNA levels parallel reductions in intestinal sugar transport

    PubMed Central

    Roche, Marjolaine; Neti, Prasad V. S. V.; Kemp, Francis W.; Agrawal, Amit; Attanasio, Alicia; Douard, Véronique; Muduli, Anjali; Azzam, Edouard I.; Norkus, Edward; Brimacombe, Michael; Howell, Roger W.

    2010-01-01

    More than a century ago, ionizing radiation was observed to damage the radiosensitive small intestine. Although a large number of studies has since shown that radiation reduces rates of intestinal digestion and absorption of nutrients, no study has determined whether radiation affects mRNA expression and dietary regulation of nutrient transporters. Since radiation generates free radicals and disrupts DNA replication, we tested the hypotheses that at doses known to reduce sugar absorption, radiation decreases the mRNA abundance of sugar transporters SGLT1 and GLUT5, prevents substrate regulation of sugar transporter expression, and causes reductions in sugar absorption that can be prevented by consumption of the antioxidant vitamin A, previously shown by us to radioprotect the testes. Mice were acutely irradiated with 137Cs gamma rays at doses of 0, 7, 8.5, or 10 Gy over the whole body. Mice were fed with vitamin A-supplemented diet (100× the control diet) for 5 days prior to irradiation after which the diet was continued until death. Intestinal sugar transport was studied at days 2, 5, 8, and 14 postirradiation. By day 8, d-glucose uptake decreased by ∼10–20% and d-fructose uptake by 25–85%. With increasing radiation dose, the quantity of heterogeneous nuclear RNA increased for both transporters, whereas mRNA levels decreased, paralleling reductions in transport. Enterocytes of mice fed the vitamin A supplement had ≥ 6-fold retinol concentrations than those of mice fed control diets, confirming considerable intestinal vitamin A uptake. However, vitamin A supplementation had no effect on clinical or transport parameters and afforded no protection against radiation-induced changes in intestinal sugar transport. Radiation markedly reduced GLUT5 activity and mRNA abundance, but high-d-fructose diets enhanced GLUT5 activity and mRNA expression in both unirradiated and irradiated mice. In conclusion, the effect of radiation may be posttranscriptional, and

  8. Radiation Transport through cylindrical foams with heated walls

    NASA Astrophysics Data System (ADS)

    Baker, Kevin; MacLaren, Steve; Kallman, Joshua; Heinz, Ken; Hsing, Warren

    2012-10-01

    Radiation transport through low density SiO2 foams has been experimentally studied on the Omega laser. In particular these experiments examined the effects on radiation transport when the boundaries of the SiO2 foam are heated such that energy loss to the boundaries is minimized. The initial density of the SiO2 foams was determined by taking an x-ray radiograph of the foams using a monochromatic Henke source at multiple x-ray energies. The radiation drive used to both study the transport in the SiO2 foam as well as to heat the higher density CRF wall was generated in a laser-heated gold hohlraum using ˜7.5 kJ of the laser energy. The time-dependent spatial profile of the heat wave breaking out of the SiO2 foam was detected with an x-ray streak camera coupled with a soft x-ray transmission grating. The Omega DANTE diagnostic measured the radiation drive in the hohlraum and the Omega VISAR diagnostic monitored the spatial temperature gradient in the foam section of the hohlraum.

  9. Los Alamos low-level waste performance assessment status

    SciTech Connect

    Wenzel, W.J.; Purtymun, W.D.; Dewart, J.M.; Rodgers, J.E.

    1986-06-01

    This report reviews the documented Los Alamos studies done to assess the containment of buried hazardous wastes. Five sections logically present the environmental studies, operational source terms, transport pathways, environmental dosimetry, and computer model development and use. This review gives a general picture of the Los Alamos solid waste disposal and liquid effluent sites and is intended for technical readers with waste management and environmental science backgrounds but without a detailed familiarization with Los Alamos. The review begins with a wide perspective on environmental studies at Los Alamos. Hydrology, geology, and meteorology are described for the site and region. The ongoing Laboratory-wide environmental surveillance and waste management environmental studies are presented. The next section describes the waste disposal sites and summarizes the current source terms for these sites. Hazardous chemical wastes and liquid effluents are also addressed by describing the sites and canyons that are impacted. The review then focuses on the transport pathways addressed mainly in reports by Healy and Formerly Utilized Sites Remedial Action Program. Once the source terms and potential transport pathways are described, the dose assessment methods are addressed. Three major studies, the waste alternatives, Hansen and Rogers, and the Pantex Environmental Impact Statement, contributed to the current Los Alamos dose assessment methodology. Finally, the current Los Alamos groundwater, surface water, and environmental assessment models for these mesa top and canyon sites are described.

  10. Topological angular momentum and radiative heat transport in closed orbits

    NASA Astrophysics Data System (ADS)

    Silveirinha, Mário G.

    2017-03-01

    We study the role of topological edge states of light in the transport of thermally generated radiation in a closed cavity at a thermodynamic equilibrium. It is shown that even in the zero temperature limit—when the field fluctuations are purely quantum mechanical—there is a persistent flow of electromagnetic momentum in the cavity in closed orbits, deeply rooted in the emergence of spatially separated unidirectional edge state channels. It is highlighted that the electromagnetic orbital angular momentum of the system is nontrivial, and that the energy circulation is towards the same direction as that determined by incomplete cyclotron orbits near the cavity walls. Our findings open inroads in topological photonics and suggest that topological states of light can determine novel paradigms in the context of radiative heat transport.

  11. Radiation Transport and Shielding for Space Exploration and High Speed Flight Transportation

    NASA Technical Reports Server (NTRS)

    Maung, Khin Maung; Trapathi, R. K.

    1997-01-01

    Transportation of ions and neutrons in matter is of direct interest in several technologically important and scientific areas, including space radiation, cosmic ray propagation studies in galactic medium, nuclear power plants and radiological effects that impact industrial and public health. For the proper assessment of radiation exposure, both reliable transport codes and accurate data are needed. Nuclear cross section data is one of the essential inputs into the transport codes. In order to obtain an accurate parametrization of cross section data, theoretical input is indispensable especially for processes where there is little or no experimental data available. In this grant period work has been done on the studies of the use of relativistic equations and their one-body limits. The results will be useful in choosing appropriate effective one-body equation for reaction calculations. Work has also been done to improve upon the data base needed for the transport codes used in the studies of radiation transport and shielding for space exploration and high speed flight transportation. A phenomenological model was developed for the total absorption cross sections valid for any system of charged and/or uncharged collision pairs for the entire energy range. The success of the model is gratifying. It is being used by other federal agencies, national labs and universities. A list of publications based on the work during the grant period is given below and copies are enclosed with this report.

  12. NERO- a post-maximum supernova radiation transport code

    NASA Astrophysics Data System (ADS)

    Maurer, I.; Jerkstrand, A.; Mazzali, P. A.; Taubenberger, S.; Hachinger, S.; Kromer, M.; Sim, S.; Hillebrandt, W.

    2011-12-01

    The interpretation of supernova (SN) spectra is essential for deriving SN ejecta properties such as density and composition, which in turn can tell us about their progenitors and the explosion mechanism. A very large number of atomic processes are important for spectrum formation. Several tools for calculating SN spectra exist, but they mainly focus on the very early or late epochs. The intermediate phase, which requires a non-local thermodynamic equilibrium (NLTE) treatment of radiation transport has rarely been studied. In this paper, we present a new SN radiation transport code, NERO, which can look at those epochs. All the atomic processes are treated in full NLTE, under a steady-state assumption. This is a valid approach between roughly 50 and 500 days after the explosion depending on SN type. This covers the post-maximum photospheric and the early and the intermediate nebular phase. As a test, we compare NERO to the radiation transport code of Jerkstrand, Fransson & Kozma and to the nebular code of Mazzali et al. All three codes have been developed independently and a comparison provides a valuable opportunity to investigate their reliability. Currently, NERO is one-dimensional and can be used for predicting spectra of synthetic explosion models or for deriving SN properties by spectral modelling. To demonstrate this, we study the spectra of the 'normal' Type Ia supernova (SN Ia) 2005cf between 50 and 350 days after the explosion and identify most of the common SN Ia line features at post-maximum epochs.

  13. Predicting radiative transport properties of plasma sprayed porous ceramics

    NASA Astrophysics Data System (ADS)

    Wang, B. X.; Zhao, C. Y.

    2016-03-01

    The typical yttria-stabilized zirconia material for making the thermal barrier coatings (TBCs) is intrinsically semitransparent to thermal radiation, and the unique disordered microstructures in TBCs make them surprisingly highly scattering. To quantitatively understand the influence of disordered microstructures, this paper presents a quantitative prediction on the radiative properties, especially the transport scattering coefficient of plasma sprayed TBC based on microstructure analysis and rigorous electromagnetic theory. The impact of the porosity, shape, size, and orientation of different types of voids on transport scattering coefficient is comprehensively investigated under the discrete dipole approximation. An inverse model integrating these factors together is then proposed to quantitatively connect transport scattering coefficient with microstructural information, which is also validated by available experimental data. Afterwards, an optimization procedure is carried out based on this model to obtain the optimal size and orientation distribution of the microscale voids to achieve the maximal radiation insulation performance at different operating temperatures, providing guidelines for practical coating design and fabrication. This work suggests that the current model is effective and also efficient for connecting scattering properties to microstructures and can be implemented as a quantitative tool for further studies like non-destructive infrared imaging as well as micro/nanoscale thermal design of TBCs.

  14. Review of liquid metal heat pipe work at Los Alamos

    SciTech Connect

    Reid, R.S.; Merrigan, M.A.; Sena, J.T.

    1990-01-01

    A survey of space-power related liquid metal heat pipe work at Los Alamos National Laboratory is presented. Heat pipe development at Los Alamos has been on-going since 1963. Heat pipes were initially developed for thermionic nuclear-electrical power production in space. Since then Los Alamos has developed liquid metal heat pipes for numerous applications related to high temperature systems in both the space and terrestrial environments. Some of these applications include thermionic electrical generators, thermoelectric energy conversion (both in-core and direct radiation), thermal energy storage, hypersonic vehicle leading edge cooling, and heat pipe vapor laser cells. Some of the work performed at Los Alamos has been documented in internal reports that are often little-known. A representative description and summary of progress in space-related liquid metal heat pipe technology is provided followed by a reference section citing sources where these works may be found. 53 refs.

  15. Review of liquid metal heat pipe work at Los Alamos

    SciTech Connect

    Reid, R.S.; Merrigan, M.A.; Sena, J.T. )

    1991-01-10

    A survey of space-power related liquid metal heat pipe work at Los Alamos National Laboratory is presented. Heat pipe development at Los Alamos has been on-going since 1963. Heat pipes were initially developed for thermionic nuclear-electrical power production in space. Since then Los Alamos has developed liquid metal heat pipes for numerous applications related to high temperature systems in both the space and terrestrial environments. Some of these applications include thermionic electrical generators, thermoelectric energy conversion (both in-core and direct radiation), thermal energy storage, hypersonic vehicle leading edge cooling, and heat pipe vapor laser cells. Some of the work performed at Los Alamos has been documented in internal reports that are often little-known. A representative description and summary of progress in space-related liquid metal heat pipe technology is provided followed by a reference section citing sources where these works may be found.

  16. Atmospheric transport, clouds and the Arctic longwave radiation paradox

    NASA Astrophysics Data System (ADS)

    Sedlar, Joseph

    2016-04-01

    Clouds interact with radiation, causing variations in the amount of electromagnetic energy reaching the Earth's surface, or escaping the climate system to space. While globally clouds lead to an overall cooling radiative effect at the surface, over the Arctic, where annual cloud fractions are high, the surface cloud radiative effect generally results in a warming. The additional energy input from absorption and re-emission of longwave radiation by the clouds to the surface can have a profound effect on the sea ice state. Anomalous atmospheric transport of heat and moisture into the Arctic, promoting cloud formation and enhancing surface longwave radiation anomalies, has been identified as an important mechanism in preconditioning Arctic sea ice for melt. Longwave radiation is emitted equally in all directions, and changes in the atmospheric infrared emission temperature and emissivity associated with advection of heat and moisture over the Arctic should correspondingly lead to an anomalous signal in longwave radiation at the top of the atmosphere (TOA). To examine the role of atmospheric heat and moisture transport into the Arctic on TOA longwave radiation, infrared satellite sounder observations from AIRS during 2003-2014 are analyzed for summer (JJAS). Thermodynamic metrics are developed to identify months characterized by a high frequency of warm and moist advection into the Arctic, and segregate the 2003-14 time period into climatological and anomalously warm, moist summer months. We find that anomalously warm, moist months result in a significant TOA longwave radiative cooling, which is opposite the forcing signal that the surface experiences during these months. At the timescale of the advective events, 3-10 days, the TOA cooling can be as large as the net surface energy budget during summer. When averaged on the monthly time scale, and over the full Arctic basin (poleward of 75°N), summer months experiencing frequent warm, moist advection events are

  17. Radiation safety of crew and passengers of air transportation in civil aviation. Provisional standards

    NASA Technical Reports Server (NTRS)

    Aksenov, A. F.; Burnazyan, A. I.

    1985-01-01

    The purpose and application of the provisional standards for radiation safety of crew and passengers in civil aviation are given. The radiation effect of cosmic radiation in flight on civil aviation air transport is described. Standard levels of radiation and conditions of radiation safety are discussed.

  18. Efficient control variates for uncertainty quantification of radiation transport

    NASA Astrophysics Data System (ADS)

    Frankel, A.; Iaccarino, G.

    2017-03-01

    Numerical simulations of problems involving radiation transport are challenging because of the associated computational cost; moreover, it is typically difficult to describe the optical properties of the system very precisely, and therefore uncertainties abound. We aim to represent the uncertainties explicitly and to characterize their impact on the output of interest. While stochastic collocation and polynomial chaos methods have been applied previously, these methods can suffer from the curse of dimensionality and fail in cases where the system response is discontinuous or highly non-linear. Monte Carlo methods are more robust, but they converge slowly. To that end, we apply the control variate method to uncertainty propagation via Monte Carlo. We leverage the modeling hierarchy of radiation transport to use low fidelity models such as the diffusion approximation and coarse angular discretizations to reduce the confidence interval on the quantity of interest. The efficiency of the control variate method is demonstrated in several problems involving stochastic media, thermal emission, and radiation properties with different quantities of interest. The control variates are able to provide significant variance reduction and efficiency increase in all problems considered. We conclude our study with a discussion of choosing optimal control variates and other extensions of Monte Carlo methods.

  19. Los Alamos National Laboratory

    SciTech Connect

    Dogliani, Harold O

    2011-01-19

    The purpose of the briefing is to describe general laboratory technical capabilities to be used for various groups such as military cadets or university faculty/students and post docs to recruit into a variety of Los Alamos programs. Discussed are: (1) development and application of high leverage science to enable effeictive, predictable and reliability outcomes; (2) deter, detect, characterize, reverse and prevent the proliferation of weapons of mass destruction and their use by adversaries and terrorists; (3) modeling and simulation to define complex processes, predict outcomes, and develop effective prevention, response, and remediation strategies; (4) energetic materials and hydrodynamic testing to develop materials for precise delivery of focused energy; (5) materials cience focused on fundamental understanding of materials behaviors, their quantum-molecular properties, and their dynamic responses, and (6) bio-science to rapidly detect and characterize pathogens, to develop vaccines and prophylactic remedies, and to develop attribution forensics.

  20. Scoring methods for implicit Monte Carlo radiation transport

    SciTech Connect

    Edwards, A.L.

    1981-01-01

    Analytical and numerical tests were made of a number of possible methods for scoring the energy exchange between radiation and matter in the implicit Monte Carlo (IMC) radiation transport scheme of Fleck and Cummings. The interactions considered were effective absorption, elastic scattering, and Compton scattering. The scoring methods tested were limited to simple combinations of analogue, linear expected value, and exponential expected value scoring. Only two scoring methods were found that produced the same results as a pure analogue method. These are a combination of exponential expected value absorption and deposition and analogue Compton scattering of the particle, with either linear expected value Compton deposition or analogue Compton deposition. In both methods, the collision distance is based on the total scattering cross section.

  1. Radiation safety aspects of commercial high-speed flight transportation

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Nealy, John E.; Cucinotta, Francis A.; Shinn, Judy L.; Hajnal, Ferenc; Reginatto, Marcel; Goldhagen, Paul

    1995-01-01

    High-speed commercial flight transportation is being studied for intercontinental operations in the 21st century, the projected operational characteristics for these aircraft are examined, the radiation environment as it is now known is presented, and the relevant health issues are discussed. Based on a critical examination of the data, a number of specific issues need to be addressed to ensure an adequate knowledge of the ionizing radiation health risks of these aircraft operations. Large uncertainties in our knowledge of the physical fields for high-energy neutrons and multiply-charged ion components need to be reduced. Improved methods for estimating risks in prenatal exposure need to be developed. A firm basis for solar flare monitoring and forecasting needs to be developed with means of exposure abatement.

  2. Radiation safety aspects of commercial high-speed flight transportation

    NASA Astrophysics Data System (ADS)

    Wilson, John W.; Nealy, John E.; Cucinotta, Francis A.; Shinn, Judy L.; Hajnal, Ferenc; Reginatto, Marcel; Goldhagen, Paul

    1995-05-01

    High-speed commercial flight transportation is being studied for intercontinental operations in the 21st century, the projected operational characteristics for these aircraft are examined, the radiation environment as it is now known is presented, and the relevant health issues are discussed. Based on a critical examination of the data, a number of specific issues need to be addressed to ensure an adequate knowledge of the ionizing radiation health risks of these aircraft operations. Large uncertainties in our knowledge of the physical fields for high-energy neutrons and multiply-charged ion components need to be reduced. Improved methods for estimating risks in prenatal exposure need to be developed. A firm basis for solar flare monitoring and forecasting needs to be developed with means of exposure abatement.

  3. A quantum transport model for atomic line radiation in plasmas*

    NASA Astrophysics Data System (ADS)

    Rosato, Joël

    2017-02-01

    Emission and absorption lines in plasmas are investigated theoretically using a phase space formulation of quantum electrodynamics. A transport equation for the one-photon Wigner function is derived and formulated in terms of the noncommutative Moyal product. This equation reduces to the standard radiative transfer equation at the large spectral band limit, when the characteristic spectral band of the emission and absorption coefficients is larger than the inverse photon absorption length and time. We examine deviations to this limit. An ideal slab geometry is considered. The Wigner function relative to hydrogen Lyman α in stellar atmospheric conditions is calculated.

  4. Development and Implementation of Photonuclear Cross-Section Data for Mutually Coupled Neutron-Photon Transport Calculations in the Monte Carlo N-Particle (MCNP) Radiation Transport Code

    SciTech Connect

    White, Morgan C.

    2000-07-01

    The fundamental motivation for the research presented in this dissertation was the need to development a more accurate prediction method for characterization of mixed radiation fields around medical electron accelerators (MEAs). Specifically, a model is developed for simulation of neutron and other particle production from photonuclear reactions and incorporated in the Monte Carlo N-Particle (MCNP) radiation transport code. This extension of the capability within the MCNP code provides for the more accurate assessment of the mixed radiation fields. The Nuclear Theory and Applications group of the Los Alamos National Laboratory has recently provided first-of-a-kind evaluated photonuclear data for a select group of isotopes. These data provide the reaction probabilities as functions of incident photon energy with angular and energy distribution information for all reaction products. The availability of these data is the cornerstone of the new methodology for state-of-the-art mutually coupled photon-neutron transport simulations. The dissertation includes details of the model development and implementation necessary to use the new photonuclear data within MCNP simulations. A new data format has been developed to include tabular photonuclear data. Data are processed from the Evaluated Nuclear Data Format (ENDF) to the new class ''u'' A Compact ENDF (ACE) format using a standalone processing code. MCNP modifications have been completed to enable Monte Carlo sampling of photonuclear reactions. Note that both neutron and gamma production are included in the present model. The new capability has been subjected to extensive verification and validation (V&V) testing. Verification testing has established the expected basic functionality. Two validation projects were undertaken. First, comparisons were made to benchmark data from literature. These calculations demonstrate the accuracy of the new data and transport routines to better than 25 percent. Second, the ability to

  5. Stormtime transport of ring current and radiation belt ions

    NASA Technical Reports Server (NTRS)

    Chen, Margaret W.; Schulz, Michael; Lyons, Larry R.; Gorney, David J.

    1993-01-01

    A dynamical guiding-center simulation model is used to study the stormtime ion transport which leads to the formation of the ring current and diffusion in the radiation belts. Representative ions guiding-center motion in response to model storm-associated impulses in the convection electric field is traced for a range of ion mu values. The present numerical results are compared with previously formulated limiting idealization of particle transport in order to assess the limits of validity of these approximations. For ions having drift periods that exceed the duration of the main phase of the storm, their inward transport to form the stormtime ring current is appropriately described as direct convective access. For ions having drift periods comparable to the duration of the main phase of the storm, there is a transition between direct convective access and transport that resembles radial diffusion. Lower-energy ring-current ions at L of about 3 are freshly injected there from open adiabatic trajectories, whereas the higher-energy ring-current population consists of a mixture of freshly injected and previously trapped ions.

  6. New Parallel computing framework for radiation transport codes

    SciTech Connect

    Kostin, M.A.; Mokhov, N.V.; Niita, K.; /JAERI, Tokai

    2010-09-01

    A new parallel computing framework has been developed to use with general-purpose radiation transport codes. The framework was implemented as a C++ module that uses MPI for message passing. The module is significantly independent of radiation transport codes it can be used with, and is connected to the codes by means of a number of interface functions. The framework was integrated with the MARS15 code, and an effort is under way to deploy it in PHITS. Besides the parallel computing functionality, the framework offers a checkpoint facility that allows restarting calculations with a saved checkpoint file. The checkpoint facility can be used in single process calculations as well as in the parallel regime. Several checkpoint files can be merged into one thus combining results of several calculations. The framework also corrects some of the known problems with the scheduling and load balancing found in the original implementations of the parallel computing functionality in MARS15 and PHITS. The framework can be used efficiently on homogeneous systems and networks of workstations, where the interference from the other users is possible.

  7. Compendium of Material Composition Data for Radiation Transport Modeling

    SciTech Connect

    McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert

    2011-03-04

    Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library

  8. Laser Generated Anisotropic Drives for Radiation Transport Validation

    NASA Astrophysics Data System (ADS)

    Lanier, N. E.; Kline, J. K.; Hager, J. D.

    2013-10-01

    Many astrophysical phenomena are studied in the laboratory by developing a scaled platform whose energy drive is produced via a laser or pulsed power facility. The push to reach more energetic regimes often results in radiation drives that diverge from well-behaved Lambertian Planckian sources. In these cases, typical diffusive radiation flow models can break down. A new platform, that deliberately generates a well-characterized non-Planckian, anisotropic source, has been developed for the OMEGA laser. The resulting data will help validate more complex computational transport schemes like Sn or implicit Monte-Carlo (IMC) models. The platform contains a SiO2 foam mounted on a half-hohlraum. Anisotropy is achieved by inserting an obstruction of either a singular round aperture or annular ring between the foam and hohlraum. In addition, a thin beryllium layer delays the thermal component of the drive while the higher energy M-shell radiation propagates unhindered. The result is a highly non-Planckian, anisotropic, supersonic drive that eventually transitions to sub-sonic. Spectroscopic measurements constrain the source anisotropy, magnitude, and spectral content. Moreover, the Marshak position coupled with spectroscopic absorption measurements quantify the foam's internal energy.

  9. Radiative transport models for solar thermal receiver/reactors

    SciTech Connect

    Bohn, M S; Mehos, M S

    1989-12-01

    Modeling the behavior of solar-driven chemical reactors requires detailed knowledge of the absorbed solar flux throughout the calculation domain. Radiative transport models, which determine the radiative intensity field and absorbed solar flux, are discussed in this paper with special attention given to particular needs for the application of solar thermal receiver/reactors. The geometry of interest is an axisymmetric cylinder with a specified intensity field at one end, diffuse reflection at boundaries, and containing a participating medium. Participating media are of interest because receiver/reactors are expected to have one or more zones containing small particles or monoliths acting as absorbers or catalyst supports, either of which will absorb, emit, and scatter radiation. A general discussion of modeling techniques is given, followed by a more complete discussion of three models -- the two-flux, discrete ordinate, and the Monte Carlo methods. The methods are compared with published benchmark solutions for simplified geometries -- the infinite cylinder and plane slab -- and for geometries more closely related to receiver/reactors. Conclusions are drawn regarding the applicability of the techniques to general receiver/reactor models considering accuracy, ease of implementation, ease of interfacing with solution techniques for the other conservation equations, and numerical efficiency. 23 refs., 6 figs., 2 tabs.

  10. Radiation protection considerations along a radioactive ion beam transport line

    NASA Astrophysics Data System (ADS)

    Sarchiapone, Lucia; Zafiropoulos, Demetre

    2016-09-01

    The goal of the SPES project is to produce accelerated radioactive ion beams for Physics studies at “Laboratori Nazionali di Legnaro” (INFN, Italy). This accelerator complex is scheduled to be built by 2016 for an effective operation in 2017. Radioactive species are produced in a uranium carbide target, by the interaction of 200 μA of protons at 40 MeV. All of the ionized species in the 1+ state come out of the target (ISOL method), and pass through a Wien filter for a first selection and an HMRS (high mass resolution spectrometer). Then they are transported by an electrostatic beam line toward a charge state breeder (where the 1+ to n+ multi-ionization takes place) before selection and reacceleration at the already existing superconducting linac. The work concerning dose evaluations, activation calculation, and radiation protection constraints related to the transport of the radioactive ion beam (RIB) from the target to the mass separator will be described in this paper. The FLUKA code has been used as tool for those calculations needing Monte Carlo simulations, in particular for the evaluation of the dose rate due to the presence of the radioactive beam in the selection/interaction points. The time evolution of a radionuclide inventory can be computed online with FLUKA for arbitrary irradiation profiles and decay times. The activity evolution is analytically evaluated through the implementation of the Bateman equations. Furthermore, the generation and transport of decay radiation (limited to gamma, beta- and beta+ emissions) is possible, referring to a dedicated database of decay emissions using mostly information obtained from NNDC, sometimes supplemented with other data and checked for consistency. When the use of Monte Carlo simulations was not feasible, the Bateman equations, or possible simplifications, have been used directly.

  11. Transport in stellar radiation zones with magnetic field

    NASA Astrophysics Data System (ADS)

    Mathis, S.; Zahn, J.-P.

    We examine the interaction between meridian circulation and turbulence in rotating stars with an axisymetric magnetic field. In the same way as Zahn (1992) and Spiegel and Zahn (1992), the turbulence is assumed to be anisotropic, due to the stratification, with stronger transport in the horizontal directions than in the vertical. We keep the 'shellular rotation' hypothesis, but we expand the differential rotation in latitude to higher order, which allow us to treat simultaneously the radiative interior and the tachocline(s). We derive the partial differential equations which govern the transport of magnetic field, temperature, angular momentum and chemical elements with taking into account the non-stationarity of the problem, the mu-gradients, the effect of horizontal turbulence in thermal imbalance and a general equation of state like in Maeder and Zahn (1998). Finally, we apply the beta-viscosity prescription which has been derived from Couette-Taylor experiments (Richard and Zahn (1999)) to the problem of transport in stellar interiors to obtain a new expression for the horizontal component of the turbulent viscosity, nuh, and its companion the horizontal diffusivity, Dh. The next step will be to implement these new equations in existing stellar structure codes, to model the evolution of rotating stars.

  12. P1 Nonconforming Finite Element Method for the Solution of Radiation Transport Problems

    NASA Technical Reports Server (NTRS)

    Kang, Kab S.

    2002-01-01

    The simulation of radiation transport in the optically thick flux-limited diffusion regime has been identified as one of the most time-consuming tasks within large simulation codes. Due to multimaterial complex geometry, the radiation transport system must often be solved on unstructured grids. In this paper, we investigate the behavior and the benefits of the unstructured P(sub 1) nonconforming finite element method, which has proven to be flexible and effective on related transport problems, in solving unsteady implicit nonlinear radiation diffusion problems using Newton and Picard linearization methods. Key words. nonconforrning finite elements, radiation transport, inexact Newton linearization, multigrid preconditioning

  13. Deriving Kubelka-Munk theory from radiative transport.

    PubMed

    Sandoval, Christopher; Kim, Arnold D

    2014-03-01

    We derive Kubelka-Munk (KM) theory systematically from the radiative transport equation (RTE) by analyzing the system of equations resulting from applying the double spherical harmonics method of order one and transforming that system into one governing the positive- and negative-going fluxes. Through this derivation, we establish the theoretical basis of KM theory, identify all parameters, and determine its range of validity. Moreover, we are able to generalize KM theory to take into account general boundary sources and nonhomogeneous terms, for example. The generalized Kubelka-Munk (gKM) equations are also much more accurate at approximating the solution of the RTE. We validate this theory through comparison with numerical solutions of the RTE.

  14. Space radiation transport properties of polyethylene-based composites.

    PubMed

    Kaul, R K; Barghouty, A F; Dahche, H M

    2004-11-01

    Composite materials that can serve as both effective shielding materials against cosmic-ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene-fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

  15. Space radiation transport properties of polyethylene-based composites

    NASA Technical Reports Server (NTRS)

    Kaul, R. K.; Barghouty, A. F.; Dahche, H. M.

    2004-01-01

    Composite materials that can serve as both effective shielding materials against cosmic-ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene-fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

  16. Radiation Transport Properties of Polyethylene-Fiber Composites

    NASA Technical Reports Server (NTRS)

    Kaul, Raj K.; Barghouty, A. F.; Dahche, H. M.

    2003-01-01

    Composite materials that can both serve as effective shielding materials against cosmic-ray and energetic solar particles in deep space as well as structural materials for habitat and spacecraft remain a critical and mission enabling piece in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density coupled with high hydrogen content. Polyethylene fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of Polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at NASA's Marshall Space Flight Center and tested against 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

  17. Validation of a comprehensive space radiation transport code.

    PubMed

    Shinn, J L; Cucinotta, F A; Simonsen, L C; Wilson, J W; Badavi, F F; Badhwar, G D; Miller, J; Zeitlin, C; Heilbronn, L; Tripathi, R K; Clowdsley, M S; Heinbockel, J H; Xapsos, M A

    1998-12-01

    The HZETRN code has been developed over the past decade to evaluate the local radiation fields within sensitive materials on spacecraft in the space environment. Most of the more important nuclear and atomic processes are now modeled and evaluation within a complex spacecraft geometry with differing material components, including transition effects across boundaries of dissimilar materials, are included. The atomic/nuclear database and transport procedures have received limited validation in laboratory testing with high energy ion beams. The codes have been applied in design of the SAGE-III instrument resulting in material changes to control injurious neutron production, in the study of the Space Shuttle single event upsets, and in validation with space measurements (particle telescopes, tissue equivalent proportional counters, CR-39) on Shuttle and Mir. The present paper reviews the code development and presents recent results in laboratory and space flight validation.

  18. Charge transport properties of CdMnTe radiation detectors

    SciTech Connect

    Kim K.; Rafiel, R.; Boardman, M.; Reinhard, I.; Sarbutt, A.; Watt, G.; Watt, C.; Uxa, S.; Prokopovich, D.A.; Belas, E.; Bolotnikov, A.E.; James, R.B.

    2012-04-11

    Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading chargecollection is reduced with increasing values of bias voltage. The electron transit time was determined from time of flight measurements. From the dependence of drift velocity on applied electric field the electron mobility was found to be n = (718 55) cm2/Vs at room temperature.

  19. Acceleration of a Monte Carlo radiation transport code

    SciTech Connect

    Hochstedler, R.D.; Smith, L.M.

    1996-03-01

    Execution time for the Integrated TIGER Series (ITS) Monte Carlo radiation transport code has been reduced by careful re-coding of computationally intensive subroutines. Three test cases for the TIGER (1-D slab geometry), CYLTRAN (2-D cylindrical geometry), and ACCEPT (3-D arbitrary geometry) codes were identified and used to benchmark and profile program execution. Based upon these results, sixteen top time-consuming subroutines were examined and nine of them modified to accelerate computations with equivalent numerical output to the original. The results obtained via this study indicate that speedup factors of 1.90 for the TIGER code, 1.67 for the CYLTRAN code, and 1.11 for the ACCEPT code are achievable. {copyright} {ital 1996 American Institute of Physics.}

  20. An Improved Neutron Transport Algorithm for Space Radiation

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Clowdsley, Martha S.; Wilson, John W.

    2000-01-01

    A low-energy neutron transport algorithm for use in space radiation protection is developed. The algorithm is based upon a multigroup analysis of the straight-ahead Boltzmann equation by using a mean value theorem for integrals. This analysis is accomplished by solving a realistic but simplified neutron transport test problem. The test problem is analyzed by using numerical and analytical procedures to obtain an accurate solution within specified error bounds. Results from the test problem are then used for determining mean values associated with rescattering terms that are associated with a multigroup solution of the straight-ahead Boltzmann equation. The algorithm is then coupled to the Langley HZETRN code through the evaporation source term. Evaluation of the neutron fluence generated by the solar particle event of February 23, 1956, for a water and an aluminum-water shield-target configuration is then compared with LAHET and MCNPX Monte Carlo code calculations for the same shield-target configuration. The algorithm developed showed a great improvement in results over the unmodified HZETRN solution. In addition, a two-directional solution of the evaporation source showed even further improvement of the fluence near the front of the water target where diffusion from the front surface is important.

  1. Stormtime transport of ring current and radiation belt ions

    NASA Technical Reports Server (NTRS)

    Chen, Margaret W.; Schulz, Michael; Lyons, L. R.; Gorney, David J.

    1993-01-01

    This is an investigation of stormtime particle transport that leads to formation of the ring current. Our method is to trace the guiding-center motion of representative ions (having selected first adiabatic invariants mu) in response to model substorm-associated impulses in the convection electric field. We compare our simulation results qualitatively with existing analytically tractable idealizations of particle transport (direct convective access and radial diffusion) in order to assess the limits of validity of these approximations. For mu approximately less than 10 MeV/G (E approximately less than 10 keV at L equivalent to 3) the ion drift period on the final (ring-current) drift shell of interest (L equivalent to 3) exceeds the duration of the main phase of our model storm, and we find that the transport of ions to this drift shell is appropriately idealized as direct convective access, typically from open drift paths. Ion transport to a final closed drift path from an open (plasma-sheet) drift trajectory is possible for those portions of that drift path that lie outside the mean stormtime separatrix between closed and open drift trajectories, For mu approximately 10-25 MeV/G (110 keV approximately less than E approximately less than 280 keV at L equivalent to 3) the drift period at L equivalent to 3 is comparable to the postulated 3-hr duration of the storm, and the mode of transport is transitional between direct convective access and transport that resembles radial diffusion. (This particle population is transitional between the ring current and radiation belt). For mu approximately greater than 25 MeV/G (radiation-belt ions having E approximately greater than 280 keV at L equivalent to 3) the ion drift period is considerably shorter than the main phase of a typical storm, and ions gain access to the ring-current region essentially via radial diffusion. By computing the mean and mean-square cumulative changes in 1/L among (in this case) 12 representative

  2. An Overview of the Los Alamos Inertial Confinement Fusion and High-Energy-Density Physics Research Programs

    SciTech Connect

    Batha, Steven H.

    2016-07-15

    The Los Alamos Inertial Confinement Fusion and Science Programs engage in a vigorous array of experiments, theory, and modeling. We use the three major High Energy Density facilities, NIF, Omega, and Z to perform experiments. These include opacity, radiation transport, hydrodynamics, ignition science, and burn experiments to aid the ICF and Science campaigns in reaching their stewardship goals. The ICF program operates two nuclear diagnostics at NIF, the neutron imaging system and the gamma reaction history instruments. Both systems are being expanded with significant capability enhancements.

  3. Environmental surveillance at Los Alamos during 1979

    SciTech Connect

    Not Available

    1980-04-01

    This report documents the environmental surveillance program conducted by the Los Alamos Scientific Laboratory (LASL) in 1979. Routine monitoring for radiation and radioactive or chemical substances was conducted on the Laboratory site and in the surrounding region to determine compliance with appropriate standards and permit early identification of possible undesirable trends. Results and interpretation of the data for 1979 on penetrating radiation, chemical and radiochemical quality of ambient air, surface and ground water, municipal water supply, soils and sediments, food, and airborne and liquid effluents are included. Comparisons with appropriate standards and regulations or with background levels from natural or other non-LASL sources provide a basis for concluding that environmental effects attributable to LASL operations are minor and cannot be considered likely to result in any hazard to the population of the area. Results of several special studies provide documentation of some unique environmental conditions in the LASL environs.

  4. Environmental surveillance at Los Alamos during 1987

    SciTech Connect

    Not Available

    1988-05-01

    This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1987. Routine monitoring for radiation and radioactive or chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1987 cover: external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface and ground waters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriate standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are insignificant and do not pose a threat to the public, Laboratory employees, or the environment. 113 refs., 33 figs., 120 tabs.

  5. Environmental surveillance at Los Alamos during 1989

    SciTech Connect

    Not Available

    1990-12-01

    This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1989. Routine monitoring for radiation and radioactive or chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1989 cover external penetrating radiation; quantities of airborne emissions and effluents; concentrations of chemicals and radionuclides in ambient air, surface and ground waters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriate standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are small and do not pose a threat to the public, Laboratory employees, or the environment. 58 refs., 31 figs., 39 tabs.

  6. Environmental surveillance at Los Alamos during 1995

    SciTech Connect

    1996-10-01

    This report describes the environmental surveillance program at Los Alamos National Laboratory (LANL or the Laboratory) during 1995. The Laboratory routinely monitors for radiation and for radioactive and nonradioactive materials at (or on) Laboratory sites as well as in the surrounding region. LANL uses the monitoring result to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1995 to assess external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Using comparisons with standards, regulations, and background levels, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, Laboratory employees, or the environment.

  7. Environmental surveillance at Los Alamos during 1992

    SciTech Connect

    Kohen, K.; Stoker, A.; Stone, G.

    1994-07-01

    This report describes the environmental surveillance program at Los Alamos National Laboratory during 1992. The Laboratory routinely monitors for radiation and for radioactive and nonradioactive materials at (or on) Laboratory sites as well as in the surrounding region. LANL uses the monitoring results to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1992 to assess external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Using comparisons with standards, regulations, and background levels, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, laboratory employees, or the environment.

  8. Guidelines for effective radiation transport for cable SGEMP modeling

    SciTech Connect

    Drumm, Clifton Russell; Fan, Wesley C.; Turner, C. David

    2014-07-01

    This report describes experiences gained in performing radiation transport computations with the SCEPTRE radiation transport code for System Generated ElectroMagnetic Pulse (SGEMP) applications. SCEPTRE is a complex code requiring a fairly sophisticated user to run the code effectively, so this report provides guidance for analysts interested in performing these types of calculations. One challenge in modeling coupled photon/electron transport for SGEMP is to provide a spatial mesh that is sufficiently resolved to accurately model surface charge emission and charge deposition near material interfaces. The method that has been most commonly used to date to compute cable SGEMP typically requires a sub-micron mesh size near material interfaces, which may be difficult for meshing software to provide for complex geometries. We present here an alternative method for computing cable SGEMP that appears to substantially relax this requirement. The report also investigates the effect of refining the energy mesh and increasing the order of the angular approximation to provide some guidance on determining reasonable parameters for the energy/angular approximation needed for x-ray environments. Conclusions for γ-ray environments may be quite different and will be treated in a subsequent report. In the course of the energy-mesh refinement studies, a bug in the cross-section generation software was discovered that may cause underprediction of the result by as much as an order of magnitude for the test problem studied here, when the electron energy group widths are much smaller than those for the photons. Results will be presented and compared using cross sections generated before and after the fix. We also describe adjoint modeling, which provides sensitivity of the total charge drive to the source energy and angle of incidence, which is quite useful for comparing the effect of changing the source environment and for determining most stressing angle of incidence and source

  9. Two dimensional (r-theta) transport model for synchrotron radiation of FRC plasma

    NASA Astrophysics Data System (ADS)

    Qerushi, Artan; Barnes, Dan; TAE Team

    2013-10-01

    A two dimensional (r-theta) transport model has been developed for describing the power loss in FRC reactor plasmas and the transport of energy due to synchrotron radiation as well as the transport of energy due to synchrotron radiation. The transport model uses 1d FRC equilibrium profiles and solves the equation of radiative transfer in two dimensions (r-theta) taking into account the absorption and emission of synchrotron radiation. Relativistic expressions are used for both the absorption and the emission coefficients of synchrotron radiation. The reflection of synchrotron radiation from metal walls is taken into account using the approach of Krajcik. The results of the two-dimensional calculations are compared with simpler 1d calculations, which use an approach developed by Dawson and Berk et al., and 0d calculations which use an approach developed by Trubnikov.

  10. [Benchmark experiment to verify radiation transport calculations for dosimetry in radiation therapy].

    PubMed

    Renner, Franziska

    2016-09-01

    Monte Carlo simulations are regarded as the most accurate method of solving complex problems in the field of dosimetry and radiation transport. In (external) radiation therapy they are increasingly used for the calculation of dose distributions during treatment planning. In comparison to other algorithms for the calculation of dose distributions, Monte Carlo methods have the capability of improving the accuracy of dose calculations - especially under complex circumstances (e.g. consideration of inhomogeneities). However, there is a lack of knowledge of how accurate the results of Monte Carlo calculations are on an absolute basis. A practical verification of the calculations can be performed by direct comparison with the results of a benchmark experiment. This work presents such a benchmark experiment and compares its results (with detailed consideration of measurement uncertainty) with the results of Monte Carlo calculations using the well-established Monte Carlo code EGSnrc. The experiment was designed to have parallels to external beam radiation therapy with respect to the type and energy of the radiation, the materials used and the kind of dose measurement. Because the properties of the beam have to be well known in order to compare the results of the experiment and the simulation on an absolute basis, the benchmark experiment was performed using the research electron accelerator of the Physikalisch-Technische Bundesanstalt (PTB), whose beam was accurately characterized in advance. The benchmark experiment and the corresponding Monte Carlo simulations were carried out for two different types of ionization chambers and the results were compared. Considering the uncertainty, which is about 0.7 % for the experimental values and about 1.0 % for the Monte Carlo simulation, the results of the simulation and the experiment coincide.

  11. Activities of the Radiation Shielding Information Center and a report on codes/data for high energy radiation transport

    SciTech Connect

    Roussin, R.W.

    1993-01-01

    From the very early days in its history Radiation Shielding Information Center (RSIC) has been involved with high energy radiation transport. The National Aeronautics and Space Administration was an early sponsor of RSIC until the completion of the Apollo Moon Exploration Program. In addition, the intranuclear cascade work of Bertini at Oak Ridge National Laboratory provided valuable resources which were made available through RSIC. Over the years, RSIC has had interactions with many of the developers of high energy radiation transport computing technology and data libraries and has been able to collect and disseminate this technology. The current status of this technology will be reviewed and prospects for new advancements will be examined.

  12. Activities of the Radiation Shielding Information Center and a report on codes/data for high energy radiation transport

    SciTech Connect

    Roussin, R.W.

    1993-03-01

    From the very early days in its history Radiation Shielding Information Center (RSIC) has been involved with high energy radiation transport. The National Aeronautics and Space Administration was an early sponsor of RSIC until the completion of the Apollo Moon Exploration Program. In addition, the intranuclear cascade work of Bertini at Oak Ridge National Laboratory provided valuable resources which were made available through RSIC. Over the years, RSIC has had interactions with many of the developers of high energy radiation transport computing technology and data libraries and has been able to collect and disseminate this technology. The current status of this technology will be reviewed and prospects for new advancements will be examined.

  13. Stochastic methods for uncertainty quantification in radiation transport

    SciTech Connect

    Fichtl, Erin D; Prinja, Anil K; Warsa, James S

    2009-01-01

    The use of generalized polynomial chaos (gPC) expansions is investigated for uncertainty quantification in radiation transport. The gPC represents second-order random processes in terms of an expansion of orthogonal polynomials of random variables and is used to represent the uncertain input(s) and unknown(s). We assume a single uncertain input-the total macroscopic cross section-although this does not represent a limitation of the approaches considered here. Two solution methods are examined: The Stochastic Finite Element Method (SFEM) and the Stochastic Collocation Method (SCM). The SFEM entails taking Galerkin projections onto the orthogonal basis, which, for fixed source problems, yields a linear system of fully -coupled equations for the PC coefficients of the unknown. For k-eigenvalue calculations, the SFEM system is non-linear and a Newton-Krylov method is employed to solve it. The SCM utilizes a suitable quadrature rule to compute the moments or PC coefficients of the unknown(s), thus the SCM solution involves a series of independent deterministic transport solutions. The accuracy and efficiency of the two methods are compared and contrasted. The PC coefficients are used to compute the moments and probability density functions of the unknown(s), which are shown to be accurate by comparing with Monte Carlo results. Our work demonstrates that stochastic spectral expansions are a viable alternative to sampling-based uncertainty quantification techniques since both provide a complete characterization of the distribution of the flux and the k-eigenvalue. Furthermore, it is demonstrated that, unlike perturbation methods, SFEM and SCM can handle large parameter uncertainty.

  14. Deterministic methods in radiation transport. A compilation of papers presented February 4-5, 1992

    SciTech Connect

    Rice, A. F.; Roussin, R. W.

    1992-06-01

    The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.

  15. Deterministic methods in radiation transport. A compilation of papers presented February 4--5, 1992

    SciTech Connect

    Rice, A.F.; Roussin, R.W.

    1992-06-01

    The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.

  16. Radiative heat transport instability in a laser produced inhomogeneous plasma

    SciTech Connect

    Bychenkov, V. Yu.; Rozmus, W.

    2015-08-15

    A laser produced high-Z plasma in which an energy balance is achieved due to radiation emission and radiative heat transfer supports ion acoustic instability. A linear dispersion relation is derived, and instability is compared to the radiation cooling instability [R. G. Evans, Plasma Phys. Controlled Fusion 27, 751 (1985)]. Under conditions of indirect drive fusion experiments, the driving term for the instability is the radiative heat flux and, in particular, the density dependence of the radiative heat conductivity. A specific example of thermal Bremsstrahlung radiation source has been considered. This instability may lead to plasma jet formation and anisotropic x-ray generation, thus affecting inertial confinement fusion related experiments.

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

    SciTech Connect

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

    1989-01-01

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

  18. Investigation of stochastic radiation transport methods in random heterogeneous mixtures

    NASA Astrophysics Data System (ADS)

    Reinert, Dustin Ray

    densely packed, optically thick kernels. A hybrid continuous energy Monte Carlo algorithm that combines homogeneous and explicit geometry models according to the energy dependent optical thickness was also developed. This resonance switch approach exhibited a remarkably high degree of accuracy in performing criticality calculations. The versatility of this hybrid modeling approach makes it an attractive acceleration strategy for a vast array of Monte Carlo radiation transport applications.

  19. A user's guide to radiation transport in ALEGRA-HEDP : version 4.6.

    SciTech Connect

    Mehlhorn, Thomas Alan; Brunner, Thomas A.

    2005-01-01

    This manual describes the input syntax to the ALEGRA radiation transport package. All input and output variables are defined, as well as all algorithmic controls. This manual describes the radiation input syntax for ALEGRA-HEDP. The ALEGRA manual[2] describes how to run the code and general input syntax. The ALEGRA-HEDP manual[13] describes the input for other physics used in high energy density physics simulations, as well as the opacity models used by this radiation package. An emission model, which is the lowest order radiation transport approximation, is also described in the ALEGRA-HEDP manual. This document is meant to be used with these other manuals.

  20. Stochastic methods for uncertainty quantification in radiation transport

    NASA Astrophysics Data System (ADS)

    Fichtl, Erin D.

    The use of stochastic spectral expansions, specifically generalized polynomial chaos (gPC) and Karhunen-Loeve (KL) expansions, is investigated for uncertainty quantification in radiation transport. The gPC represents second-order random processes in terms of an expansion of orthogonal polynomials of random variables. The KL expansion is a Fourier-type expansion that represents a second-order random process with known covariance function in terms of a set of uncorrelated random variables and the eigenmodes of the covariance function. The flux and, in multiplying materials, the k-eigenvalue, which are the problem unknowns, are always expanded in a gPC expansion since their covariance functions are also unknown. This work assumes a single uncertain input---the total macroscopic cross section---although this does not represent a limitation of the approaches considered here. Two particular types of input parameter uncertainty are investigated: The cross section as a univariate Gaussian, log-normal, gamma or beta random variable, and the cross section as a spatially varying Gaussian or log-normal random process. In the first case, a gPC expansion in terms of a univariate random variable suffices, while in the second, a truncated KL expansion is first necessary followed by a gPC expansion in terms of multivariate random variables. Two solution methods are examined: The Stochastic Finite Element Method (SFEM) and the Stochastic Collocation Method (SCM). The SFEM entails taking Galerkin projections onto the orthogonal basis, which yields a system of fully-coupled equations for the PC coefficients of the flux and the k-eigenvalue. This system is linear when there is no multiplication and can be solved using Richardson iteration, employing a standard operator splitting such as block Gauss-Seidel or block Jacobi, or a Krylov iterative method, which can be preconditioned using these splittings. When multiplication is present, the SFEM system is non-linear and a Newton

  1. Los Alamos Advanced Free-Electron Laser

    SciTech Connect

    Chan, K.C.D.; Kraus, R.H.; Ledford, J.; Meier, K.L.; Meyer, R.E.; Nguyen, D.; Sheffield, R.L.; Sigler, F.L.; Young, L.M.; Wang, T.S.; Wilson, W.L.; Wood, R.L.

    1991-01-01

    At Los Alamos, we are building a free-electron laser (FEL) for industrial, medical, and research applications. This FEL, which will incorporate many of the new technologies developed over the last decade, will be compact in size, robust, and user-friendly. Electrons produced by a photocathode will be accelerated to 20 MeV by a high-brightness accelerator and transported using permanent-magnet quadrupoles and dipoles. They will form an electron beam with an excellent instantaneous beam quality of 10 {pi} mm mrad in transverse emittance and 0.3% in energy spread at a peak current up to 300 A. Including operation at higher harmonics, the laser wavelength extends form 3.7 {mu}m to 0.4 {mu}m. In this paper, we will describe the project and the programs to date. 10 refs., 10 figs., 1 tab.

  2. Radiation inactivation studies of renal brush border water and urea transport

    SciTech Connect

    Verkman, A.S.; Dix, J.A.; Seifter, J.L.; Skorecki, K.L.; Jung, C.Y.; Ausiello, D.A.

    1985-12-01

    Radiation inactivation was used to determine the nature and molecular weight of water and urea transport pathways in brush border membrane vesicles (BBMV) isolated from rabbit renal cortex. BBMV were frozen to -50 degrees C, irradiated with 1.5 MeV electrons, thawed, and assayed for transport or enzyme activity. The freezing process had no effect on enzyme or transport kinetics. BBMV alkaline phosphatase activity gave linear ln(activity) vs. radiation dose plots with a target size of 68 +/- 3 kDa, similar to previously reported values. Water and solute transport were measured using the stopped-flow light-scattering technique. The rates of acetamide and osmotic water transport did not depend on radiation dose (0-7 Mrad), suggesting that transport of these substances does not require a protein carrier. In contrast, urea and thiourea transport gave linear ln(activity) vs. dose curves with a target size of 125-150 kDa; 400 mM urea inhibited thiourea flux by -50% at 0 and 4.7 Mrad, showing that radiation does not affect inhibitor binding to surviving transporters. These studies suggest that BBMV urea transport requires a membrane protein, whereas osmotic water transport does not.

  3. Satellites monitor Los Alamos fires

    NASA Astrophysics Data System (ADS)

    Kalluri, Satya; White, Benjamin

    A man-made fire that was intended to be a “controlled burn” for clearing brush and wilderness at the Bandelier National Monument, New Mexico, became an inferno that devastated significant portions of Los Alamos during the first week of May 2000. Now known as the Cerro Grande fire, it was not confined to Los Alamos alone. The fire spread to 15% of the Santa Clara Indian Reservation and a substantial area of the surrounding national parks and U.S. forests.The National Weather Service estimates that more than 100,000 fires occur in the natural environment each year within the United States alone, of which about 90% are manmade. Remote sensing images from satellites could be used to detect and monitor these active fires and biomass burning. Forest fires have a significant environmental and economic impact, and timely information about their location and magnitude is essential to contain them.

  4. Activities of the Radiation Shielding Information Center and a report on codes/data for high energy radiation transport

    SciTech Connect

    Roussin, R.W.

    1994-10-01

    From the very early days in its history RSIC has been involved with high energy radiation transport. The National Aeronautics and Space Administration was an early sponsor of RSIC until the completion of the Apollo Moon Exploration Program. In addition, the intranuclear cascade work of Bertini at Oak Ridge National Laboratory provided valuable resources which were made available through RSIC. Over the years, RSIC has had interactions with many of the developers of high energy radiation transport computing technology and data libraries and has been able to collect and disseminate this technology. The current status of this technology will be reviewed and prospects for new advancements will be examined.

  5. Summary of environmental surveillance at Los Alamos during 1995

    SciTech Connect

    1996-10-01

    Linking the Rio Grande Valley and the Jemez Mountains, New Mexico`s Pajarito Plateau is home to a world-class scientific institution. Los Alamos National Laboratory (or the Laboratory), managed by the Regents of the University of California, is a government-owned, Department of Energy-supervised complex investigating all areas of modern science for the purposes of national defense, health, conservation, and ecology. The Laboratory was founded in 1943 as part of the Manhattan Project, whose members assembled to create the first nuclear weapon. Occupying the campus of the Los Alamos Ranch School, American and British scientists gathered on the isolated mesa tops to harness recently discovered nuclear power with the hope of ending World War II. In July 1945, the initial objective of the Laboratory, a nuclear device, was achieved in Los Alamos and tested in White Sands, New Mexico. Today the Laboratory continues its role in defense, particularly in nuclear weapons, including developing methods for safely handling weapons and managing waste. For the past twenty years, the Laboratory has published an annual environmental report. This pamphlet offers a synopsis that briefly explains important concepts, such as radiation and provides a summary of the monitoring results and regulatory compliance status that are explained at length in the document entitled Environmental Surveillance at Los Alamos during 1995.

  6. Multifrequency analysis of cosmic microwave background radiation and radiation transport in simulations of reionization

    NASA Astrophysics Data System (ADS)

    Huffenberger, Kevin Michael

    2006-06-01

    We explore two means for probing cosmology, through multifrequency microwave background measurements and through future observations of the epoch of reionization. We use multi-frequency information in first year Wilkinson Microwave Anisotropy Probe (WMAP) data to search for the Sunyaev-Zel'dovich (SZ) effect. We derive an optimal combination of WMAP cross-spectra to extract SZ, limiting the SZ contribution to less than 2% (95% c.l.) at the first acoustic peak in W band. Under the assumption that the removed radio point sources are not correlated with SZ, this limit implies s 8 < 1.07 at 95% c.l. The next generation of microwave telescopes will study the sky at high resolution, scales where both primary and secondary anisotropies are important. We focus on the Atacama Cosmology Telescope (ACT), simulating observations in three channels, and extracting power spectra in a multifrequency analysis. We find that both radio and infrared extragalactic point sources are important contaminants, but can be effectively removed given three (or more) channels and a good understanding of their frequency dependence. However, improper treatment of the scatter in the point source frequency dependence introduces a large systematic bias. The kinetic SZ effect corrupts measurements of the primordial slope and amplitude on small scales. We discuss the non-Gaussianity of the one- point probability distribution function as a way to constrain the kinetic SZ effect, developing a method for distinguishing this effect. We explore the simulation of maps for ACT, their application to the ACT survey geometry, and filtering techniques to recover signals. Recent work suggests that cosmological fluctuations in reionization developon scales of tens or hundreds of comoving megaparsecs.We build models of ionizing sources from simulations, concluding that a large-scale simulation will require radiation transport from a large fraction of the grid cells. Simulations at a reasonable resolution will have

  7. Radiation Transport Through a Particle Laden Turbulent Flow

    NASA Astrophysics Data System (ADS)

    Torres, Hilario; Iaccarino, Gianluca

    2016-11-01

    Direct numerical simulations of a turbulent duct flow laden with small particles was performed at several Reynolds and Stokes numbers. After the flow reached a statistically stationary state the instantaneous particle positions were saved at several time steps. Separate radiative heat transfer calculations were performed to study the amount of absorbed radiation and the local heat flux. The radiative source was considered outside of the duct, and one wall contained a window from which thermal radiation streamed through. The fluid was treated as transparent and the instantaneous particle positions obtained from the DNS where used to build Eulerian absorption and scattering fields. A Monte Carlo ray tracing code has been developed and used to solve for the radiative intensity, incident radiation, and heat flux inside of the domain. The qualitative behavior of the radiation fields as the particle positions change due to the turbulence are discussed. The effects of changes in the resolution of the Eulerian mesh used to convert the Lagrangian particles into absorption and scattering fields are also presented. The sensitivity of the amount of total absorbed radiation in the domain is also discussed in both of the previously mentioned cases.

  8. Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

    NASA Astrophysics Data System (ADS)

    Rozwadowska, Anna; Stachlewska, Iwona S.; Makuch, P.; Markowicz, K. M.; Petelski, T.; Strzałkowska, A.; Zieliński, T.

    2013-05-01

    Properties of atmospheric aerosols and solar radiation reaching the Earth's surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.

  9. Radiation transport phenomena and modeling. Part A: Codes; Part B: Applications with examples

    SciTech Connect

    Lorence, L.J. Jr.; Beutler, D.E.

    1997-09-01

    This report contains the notes from the second session of the 1997 IEEE Nuclear and Space Radiation Effects Conference Short Course on Applying Computer Simulation Tools to Radiation Effects Problems. Part A discusses the physical phenomena modeled in radiation transport codes and various types of algorithmic implementations. Part B gives examples of how these codes can be used to design experiments whose results can be easily analyzed and describes how to calculate quantities of interest for electronic devices.

  10. A Photon Free Method to Solve Radiation Transport Equations

    SciTech Connect

    Chang, B

    2006-09-05

    The multi-group discrete-ordinate equations of radiation transfer is solved for the first time by Newton's method. It is a photon free method because the photon variables are eliminated from the radiation equations to yield a N{sub group}XN{sub direction} smaller but equivalent system of equations. The smaller set of equations can be solved more efficiently than the original set of equations. Newton's method is more stable than the Semi-implicit Linear method currently used by conventional radiation codes.

  11. Portable MRI developed at Los Alamos

    SciTech Connect

    Espy, Michelle

    2015-04-22

    Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are

  12. Portable MRI developed at Los Alamos

    ScienceCinema

    Espy, Michelle

    2016-07-12

    Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are

  13. Recent Developments in Three Dimensional Radiation Transport Using the Green's Function Technique

    NASA Technical Reports Server (NTRS)

    Rockell, Candice; Tweed, John; Blattnig, Steve R.; Mertens, Christopher J.

    2010-01-01

    In the future, astronauts will be sent into space for longer durations of time compared to previous missions. The increased risk of exposure to dangerous radiation, such as Galactic Cosmic Rays and Solar Particle Events, is of great concern. Consequently, steps must be taken to ensure astronaut safety by providing adequate shielding. In order to better determine and verify shielding requirements, an accurate and efficient radiation transport code based on a fully three dimensional radiation transport model using the Green's function technique is being developed

  14. On the Development of a Deterministic Three-Dimensional Radiation Transport Code

    NASA Technical Reports Server (NTRS)

    Rockell, Candice; Tweed, John

    2011-01-01

    Since astronauts on future deep space missions will be exposed to dangerous radiations, there is a need to accurately model the transport of radiation through shielding materials and to estimate the received radiation dose. In response to this need a three dimensional deterministic code for space radiation transport is now under development. The new code GRNTRN is based on a Green's function solution of the Boltzmann transport equation that is constructed in the form of a Neumann series. Analytical approximations will be obtained for the first three terms of the Neumann series and the remainder will be estimated by a non-perturbative technique . This work discusses progress made to date and exhibits some computations based on the first two Neumann series terms.

  15. Los Alamos Science: Number 16

    SciTech Connect

    Cooper, N.G.

    1988-01-01

    It was an unusually stimulating day and a half at Los Alamos when two Nobel Laureates in physiology, a leading paleontologist, and a leading bio-astrophysicist came together to discuss ''Unsolved Problems in the Science of Life,'' the topic of the second in a series of special meetings sponsored by the Fellows of the Laboratory. Just like the first one on ''Creativity in Science,'' this colloquium took us into a broader arena of ideas and viewpoints than is our usual daily fare. To contemplate the evolution and mysteries of intelligent life from the speakers' diverse points of view at one time, in one place was indeed a rare experience.

  16. Enhanced radial transport and energization of radiation belt electrons due to drift orbit bifurcations.

    PubMed

    Ukhorskiy, A Y; Sitnov, M I; Millan, R M; Kress, B T; Smith, D C

    2014-01-01

    [1]Relativistic electron intensities in Earth's outer radiation belt can vary by multiple orders of magnitude on the time scales ranging from minutes to days. One fundamental process contributing to dynamic variability of radiation belt intensities is the radial transport of relativistic electrons across their drift shells. In this paper we analyze the properties of three-dimensional radial transport in a global magnetic field model driven by variations in the solar wind dynamic pressure. We use a test particle approach which captures anomalous effects such as drift orbit bifurcations. We show that the bifurcations lead to an order of magnitude increase in radial transport rates and enhance the energization at large equatorial pitch angles. Even at quiet time fluctuations in dynamic pressure, radial transport at large pitch angles exhibits strong deviations from the diffusion approximation. The radial transport rates are much lower at small pitch angle values which results in a better agreement with the diffusion approximation.

  17. The Roles of Transport and Wave-Particle Interactions on Radiation Belt Dynamics

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua

    2011-01-01

    Particle fluxes in the radiation belts can vary dramatically during geomagnetic active periods. Transport and wave-particle interactions are believed to be the two main types of mechanisms that control the radiation belt dynamics. Major transport processes include substorm dipolarization and injection, radial diffusion, convection, adiabatic acceleration and deceleration, and magnetopause shadowing. Energetic electrons and ions are also subjected to pitch-angle and energy diffusion when interact with plasma waves in the radiation belts. Important wave modes include whistler mode chorus waves, plasmaspheric hiss, electromagnetic ion cyclotron waves, and magnetosonic waves. We investigate the relative roles of transport and wave associated processes in radiation belt variations. Energetic electron fluxes during several storms are simulated using our Radiation Belt Environment (RBE) model. The model includes important transport and wave processes such as substorm dipolarization in global MHD fields, chorus waves, and plasmaspheric hiss. We discuss the effects of these competing processes at different phases of the storms and validate the results by comparison with satellite and ground-based observations. Keywords: Radiation Belts, Space Weather, Wave-Particle Interaction, Storm and Substorm

  18. Nonlocality of radiative transfer in continuous spectra and Bremsstrahlung radiation transport in hot dense plasmas

    SciTech Connect

    Ivanov, V. V.; Kukushkin, A. B.

    1997-05-05

    The importance of nonlocal effects in radiative transfer in continuous spectra is shown in numerical modelling of space profiles of plasma temperature and Bremsstrahlung total power losses in a layer of adiabatically compressed hot dense plasma, via comparing the results of the exact, integral equation formalism and widely used approach of radiation temperature diffusion with Rosseland mean diffusion coefficient.

  19. Energy distributions and radiation transport in uranium plasmas

    NASA Technical Reports Server (NTRS)

    Miley, G. H.; Bathke, C.; Maceda, E.; Choi, C.

    1976-01-01

    An approximate analytic model, based on continuous electron slowing, has been used for survey calculations. Where more accuracy is required, a Monte Carlo technique is used which combines an analytic representation of Coulombic collisions with a random walk treatment of inelastic collisions. The calculated electron distributions have been incorporated into another code that evaluates both the excited atomic state densities within the plasma and the radiative flux emitted from the plasma.

  20. Analysis of transport of collimated radiation in a participating media using the lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Mishra, Subhash C.; Vernekar, Rohan Ranganath

    2012-11-01

    Application of the lattice Boltzmann method (LBM) recently proposed by Asinari et al. [Asinari P, Mishra SC, Borchiellini R. A lattice Boltzmann formulation to the analysis of radiative heat transfer problems in a participating medium. Numer Heat Transfer B 2010; 57:126-146] is extended to the analysis of transport of collimated radiation in a planar participating medium. To deal with azimuthally symmetric radiation in planar medium, a new lattice structure for the LBM is used. The transport of the collimated component in the medium is analysed by two different, viz., flux splitting and direct approaches. For different angles of incidence of the collimated radiation, the LBM formulation is tested for the effects of the extinction coefficient, the anisotropy factor, and the boundary emissivities on heat flux and emissive power distributions. Results are compared with the benchmark results obtained using the finite volume method. Both the approaches in LBM provide accurate results.

  1. MESTRN: A Deterministic Meson-Muon Transport Code for Space Radiation

    NASA Technical Reports Server (NTRS)

    Blattnig, Steve R.; Norbury, John W.; Norman, Ryan B.; Wilson, John W.; Singleterry, Robert C., Jr.; Tripathi, Ram K.

    2004-01-01

    A safe and efficient exploration of space requires an understanding of space radiations, so that human life and sensitive equipment can be protected. On the way to these sensitive sites, the radiation fields are modified in both quality and quantity. Many of these modifications are thought to be due to the production of pions and muons in the interactions between the radiation and intervening matter. A method used to predict the effects of the presence of these particles on the transport of radiation through materials is developed. This method was then used to develop software, which was used to calculate the fluxes of pions and muons after the transport of a cosmic ray spectrum through aluminum and water. Software descriptions are given in the appendices.

  2. Transport calculations and accelerator experiments needed for radiation risk assessment in space.

    PubMed

    Sihver, Lembit

    2008-01-01

    The major uncertainties on space radiation risk estimates in humans are associated to the poor knowledge of the biological effects of low and high LET radiation, with a smaller contribution coming from the characterization of space radiation field and its primary interactions with the shielding and the human body. However, to decrease the uncertainties on the biological effects and increase the accuracy of the risk coefficients for charged particles radiation, the initial charged-particle spectra from the Galactic Cosmic Rays (GCRs) and the Solar Particle Events (SPEs), and the radiation transport through the shielding material of the space vehicle and the human body, must be better estimated Since it is practically impossible to measure all primary and secondary particles from all possible position-projectile-target-energy combinations needed for a correct risk assessment in space, accurate particle and heavy ion transport codes must be used. These codes are also needed when estimating the risk for radiation induced failures in advanced microelectronics, such as single-event effects, etc., and the efficiency of different shielding materials. It is therefore important that the models and transport codes will be carefully benchmarked and validated to make sure they fulfill preset accuracy criteria, e.g. to be able to predict particle fluence, dose and energy distributions within a certain accuracy. When validating the accuracy of the transport codes, both space and ground based accelerator experiments are needed The efficiency of passive shielding and protection of electronic devices should also be tested in accelerator experiments and compared to simulations using different transport codes. In this paper different multipurpose particle and heavy ion transport codes will be presented, different concepts of shielding and protection discussed, as well as future accelerator experiments needed for testing and validating codes and shielding materials.

  3. Radiation Transport in a Nitrogen Plasma General Formalism and 1- Dimensional Model

    DTIC Science & Technology

    1986-11-21

    large compared to the optical depth of the radiation, the diffusion approximation 5 S ." method, as developed in neutron transport theory , may be...Spectrosc. Radiat. Transfer 25, 551 (1981). 3. A. S . Eddington , The Internal Constitution of the Stars, Cambridge Univ. Press--T-7sT6). Also Dover, New...DC 20350 ATTN: Dr. C. F. Sharn (OPO987 ) U. S . Army Ballistics Research Laboratory Aberdeen Proving Ground, Maryland 21005 ATTN: Dr. Donald Eccleshall

  4. Analytical Radiation Transport Benchmarks for The Next Century

    SciTech Connect

    B.D. Ganapol

    2005-01-19

    Verification of large-scale computational algorithms used in nuclear engineering and radiological applications is an essential element of reliable code performance. For this reason, the development of a suite of multidimensional semi-analytical benchmarks has been undertaken to provide independent verification of proper operation of codes dealing with the transport of neutral particles. The benchmarks considered cover several one-dimensional, multidimensional, monoenergetic and multigroup, fixed source and critical transport scenarios. The first approach, called the Green's Function. In slab geometry, the Green's function is incorporated into a set of integral equations for the boundary fluxes. Through a numerical Fourier transform inversion and subsequent matrix inversion for the boundary fluxes, a semi-analytical benchmark emerges. Multidimensional solutions in a variety of infinite media are also based on the slab Green's function. In a second approach, a new converged SN method is developed. In this method, the SN solution is ''minded'' to bring out hidden high quality solutions. For this case multigroup fixed source and criticality transport problems are considered. Remarkably accurate solutions can be obtained with this new method called the Multigroup Converged SN (MGCSN) method as will be demonstrated.

  5. Los Alamos PC estimating system

    SciTech Connect

    Stutz, R.A.; Lemon, G.D.

    1987-01-01

    The Los Alamos Cost Estimating System (QUEST) is being converted to run on IBM personal computers. This very extensive estimating system is capable of supporting cost estimators from many different and varied fields. QUEST does not dictate any fixed method for estimating. QUEST supports many styles and levels of detail estimating. QUEST can be used with or without data bases. This system allows the estimator to provide reports based on levels of detail defined by combining work breakdown structures. QUEST provides a set of tools for doing any type of estimate without forcing the estimator to use any given method. The level of detail in the estimate can be mixed based on the amount of information known about different parts of the project. The system can support many different data bases simultaneously. Estimators can modify any cost in any data base.

  6. Towards a 3D Space Radiation Transport Code

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Tripathl, R. K.; Cicomptta, F. A.; Heinbockel, J. H.; Tweed, J.

    2002-01-01

    High-speed computational procedures for space radiation shielding have relied on asymptotic expansions in terms of the off-axis scatter and replacement of the general geometry problem by a collection of flat plates. This type of solution was derived for application to human rated systems in which the radius of the shielded volume is large compared to the off-axis diffusion limiting leakage at lateral boundaries. Over the decades these computational codes are relatively complete and lateral diffusion effects are now being added. The analysis for developing a practical full 3D space shielding code is presented.

  7. Dissipation and Vertical Energy Transport in Radiation-dominated Accretion Disks

    NASA Astrophysics Data System (ADS)

    Blaes, Omer; Krolik, Julian H.; Hirose, Shigenobu; Shabaltas, Natalia

    2011-06-01

    Standard models of radiation-supported accretion disks generally assume that diffusive radiation flux is solely responsible for vertical heat transport. This requires that heat must be generated at a critical rate per unit volume if the disk is to be in hydrostatic and thermal equilibrium. This raises the question of how heat is generated and how energy is transported in MHD turbulence. By analysis of a number of radiation/MHD stratified shearing-box simulations, we show that the divergence of the diffusive radiation flux is indeed capped at the critical rate, but deep inside the disk, substantial vertical energy flux is also carried by advection of radiation. Work done by radiation pressure is a significant part of the energy budget, and much of this work is dissipated later through damping by radiative diffusion. We show how this damping can be measured in the simulations and identify its physical origins. Radiative damping accounts for as much as tens of percent of the total dissipation and is the only realistic physical mechanism for dissipation of turbulence that can actually be resolved in numerical simulations of accretion disks. Buoyancy associated with dynamo-driven, highly magnetized, nearly isobaric nonlinear slow magnetosonic fluctuations is responsible for the radiation advection flux and also explains the persistent periodic magnetic upwelling seen at all values of the radiation to gas pressure ratio. The intimate connection between radiation advection and magnetic buoyancy is the first example we know of in astrophysics in which a dynamo has direct impact on the global energetics of a system.

  8. DISSIPATION AND VERTICAL ENERGY TRANSPORT IN RADIATION-DOMINATED ACCRETION DISKS

    SciTech Connect

    Blaes, Omer; Shabaltas, Natalia; Krolik, Julian H.; Hirose, Shigenobu

    2011-06-01

    Standard models of radiation-supported accretion disks generally assume that diffusive radiation flux is solely responsible for vertical heat transport. This requires that heat must be generated at a critical rate per unit volume if the disk is to be in hydrostatic and thermal equilibrium. This raises the question of how heat is generated and how energy is transported in MHD turbulence. By analysis of a number of radiation/MHD stratified shearing-box simulations, we show that the divergence of the diffusive radiation flux is indeed capped at the critical rate, but deep inside the disk, substantial vertical energy flux is also carried by advection of radiation. Work done by radiation pressure is a significant part of the energy budget, and much of this work is dissipated later through damping by radiative diffusion. We show how this damping can be measured in the simulations and identify its physical origins. Radiative damping accounts for as much as tens of percent of the total dissipation and is the only realistic physical mechanism for dissipation of turbulence that can actually be resolved in numerical simulations of accretion disks. Buoyancy associated with dynamo-driven, highly magnetized, nearly isobaric nonlinear slow magnetosonic fluctuations is responsible for the radiation advection flux and also explains the persistent periodic magnetic upwelling seen at all values of the radiation to gas pressure ratio. The intimate connection between radiation advection and magnetic buoyancy is the first example we know of in astrophysics in which a dynamo has direct impact on the global energetics of a system.

  9. Radiation transport around axisymmetric blunt body vehicles using a modified differential approximation

    NASA Technical Reports Server (NTRS)

    Hartung, Lin C.; Hassan, H. A.

    1992-01-01

    A moment method for computing 3D radiative transport in axisymmetric thermochemical nonequilibrium flows is developed. The method uses the P-1 approximation to reduce the governing system of integro-differential equations to a coupled set of partial differential equations. The numerical solution of these equations for realistic variations of the radiation properties is discussed. Representative results from the method are shown and compared to tangent slab calculations. The agreement between the transport methods is found to be about 10 percent in the stagnation region, with the difference increasing along the flank of the vehicle.

  10. Cloud-radiative effects on implied oceanic energy transports as simulated by atmospheric general circulation models

    SciTech Connect

    Gleckler, P.J.; Randall, D.A.; Boer, G.

    1994-03-01

    This paper reports on energy fluxes across the surface of the ocean as simulated by fifteen atmospheric general circulation models in which ocean surface temperatures and sea-ice boundaries are prescribed. The oceanic meridional energy transport that would be required to balance these surface fluxes is computed, and is shown to be critically sensitive to the radiative effects of clouds, to the extent that even the sign of the Southern Hemisphere ocean energy transport can be affected by the errors in simulated cloud-radiation interactions.

  11. Development of A Monte Carlo Radiation Transport Code System For HEDS: Status Update

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.; Gabriel, Tony A.; Miller, Thomas M.

    2003-01-01

    Modifications of the Monte Carlo radiation transport code HETC are underway to extend the code to include transport of energetic heavy ions, such as are found in the galactic cosmic ray spectrum in space. The new HETC code will be available for use in radiation shielding applications associated with missions, such as the proposed manned mission to Mars. In this work the current status of code modification is described. Methods used to develop the required nuclear reaction models, including total, elastic and nuclear breakup processes, and their associated databases are also presented. Finally, plans for future work on the extended HETC code system and for its validation are described.

  12. Basic knowledge on radiative and transport properties to begin in thermal plasmas modelling

    SciTech Connect

    Cressault, Y.

    2015-05-15

    This paper has for objectives to present the radiative and the transport properties for people beginning in thermal plasmas. The first section will briefly recall the equations defined in numerical models applied to thermal plasmas; the second section will particularly deal with the estimation of radiative losses; the third part will quickly present the thermodynamics properties; and the last part will concern the transport coefficients (thermal conductivity, viscosity and electrical conductivity of the gas or mixtures of gases). We shall conclude the paper with a discussion about the validity of these results the lack of data for some specific applications, and some perspectives concerning these properties for non-equilibrium thermal plasmas.

  13. Transient conductive, radiative heat transfer coupled with moisture transport in attic insulations

    NASA Astrophysics Data System (ADS)

    Gorthala, R.; Harris, K. T.; Roux, J. A.; McCarty, T. A.

    1994-01-01

    A transient, one-dimensional thermal model that incorporates combined conduction, radiation heat transfer, and moisture transport for residential attic insulations has been developed. The governing equations are the energy equation, the radiative transport equation for volumetric radiation within the insulation batt, and the species equations for bound H2O and vapor H2O. A simultaneous solution procedure with a Eulerian control volume-based finite difference method was used to solve the energy equation and the species equations. The method of discrete ordinates was used in solving the radiative transport equation. For H2O transport, both diffusion of vapor H2O and bound H2O and moisture adsorption/desorption within the insulation binder are included in the model. The experimental data measured at an occupied North Mississippi residence for R19STD (standard R19 fiberglass insulation batt without a foil radiant barrier) were used to validate the model which predicted heat fluxes for summer, spring, winter, and fall seasonal conditions. These predictions were compared with the measured heat flux data and the predictions from the dry model (without the moisture transport). Various profiles such as temperature-time histories, relative humidity time histories, spatial H2O concentrations, spatial temperatures, and spatial heat fluxes are presented to explain the overall heat transfer behavior.

  14. Los Alamos, Toshiba probing Fukushima with cosmic rays

    SciTech Connect

    Morris, Christopher

    2014-06-16

    Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

  15. Los Alamos, Toshiba probing Fukushima with cosmic rays

    ScienceCinema

    Morris, Christopher

    2016-07-12

    Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

  16. Radiation Transport in 3D Heterogeneous Materials: DNS

    SciTech Connect

    Graziani, F

    2003-07-09

    In order to develop a phenomenological approach to transport in 3D heterogeneous media, we have performed direct numerical simulation studies. Using an algorithm based on the lattice random walk to generate random media, we have performed radiographic shots of the sample and digitized both the chord length and optical depth distributions. The optical depth distribution is then used to compute an effective mean free path. As theory predicts, the atomically averaged mean free path is always a minimum value. We have also demonstrated a dependency of mean free path on the distribution of random material.

  17. A general hybrid radiation transport scheme for star formation simulations on an adaptive grid

    SciTech Connect

    Klassen, Mikhail; Pudritz, Ralph E.; Kuiper, Rolf; Peters, Thomas; Banerjee, Robi; Buntemeyer, Lars

    2014-12-10

    Radiation feedback plays a crucial role in the process of star formation. In order to simulate the thermodynamic evolution of disks, filaments, and the molecular gas surrounding clusters of young stars, we require an efficient and accurate method for solving the radiation transfer problem. We describe the implementation of a hybrid radiation transport scheme in the adaptive grid-based FLASH general magnetohydrodyanmics code. The hybrid scheme splits the radiative transport problem into a raytracing step and a diffusion step. The raytracer captures the first absorption event, as stars irradiate their environments, while the evolution of the diffuse component of the radiation field is handled by a flux-limited diffusion solver. We demonstrate the accuracy of our method through a variety of benchmark tests including the irradiation of a static disk, subcritical and supercritical radiative shocks, and thermal energy equilibration. We also demonstrate the capability of our method for casting shadows and calculating gas and dust temperatures in the presence of multiple stellar sources. Our method enables radiation-hydrodynamic studies of young stellar objects, protostellar disks, and clustered star formation in magnetized, filamentary environments.

  18. A General Hybrid Radiation Transport Scheme for Star Formation Simulations on an Adaptive Grid

    NASA Astrophysics Data System (ADS)

    Klassen, Mikhail; Kuiper, Rolf; Pudritz, Ralph E.; Peters, Thomas; Banerjee, Robi; Buntemeyer, Lars

    2014-12-01

    Radiation feedback plays a crucial role in the process of star formation. In order to simulate the thermodynamic evolution of disks, filaments, and the molecular gas surrounding clusters of young stars, we require an efficient and accurate method for solving the radiation transfer problem. We describe the implementation of a hybrid radiation transport scheme in the adaptive grid-based FLASH general magnetohydrodyanmics code. The hybrid scheme splits the radiative transport problem into a raytracing step and a diffusion step. The raytracer captures the first absorption event, as stars irradiate their environments, while the evolution of the diffuse component of the radiation field is handled by a flux-limited diffusion solver. We demonstrate the accuracy of our method through a variety of benchmark tests including the irradiation of a static disk, subcritical and supercritical radiative shocks, and thermal energy equilibration. We also demonstrate the capability of our method for casting shadows and calculating gas and dust temperatures in the presence of multiple stellar sources. Our method enables radiation-hydrodynamic studies of young stellar objects, protostellar disks, and clustered star formation in magnetized, filamentary environments.

  19. Experiences with radiation portal detectors for international rail transport

    NASA Astrophysics Data System (ADS)

    Stromswold, D. C.; McCormick, K.; Todd, L.; Ashbaker, E. D.; Evans, J. C.

    2006-08-01

    Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site, the trains carried inter-modal containers that had been unloaded from ships, and at the other site, the trains contained bulk cargo in tanker cars and hopper cars or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting portion of the program GADRAS developed at Sandia National Laboratories. For most of the NORM, the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.

  20. Experiences with radiation portal detectors for international rail transport

    SciTech Connect

    Stromswold, David C.; McCormick, Kathleen R.; Todd, Lindsay C.; Ashbaker, Eric D.; Evans, J. C.

    2006-08-30

    Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site the trains carried inter-modal containers that had been unloaded from ships, and at the other site the trains contained bulk cargo or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting program GADRAS/FitToDB from Sandia National Laboratories. For much of the NORM the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.

  1. Experience with the loading and transport of fuel assembly transport casks, including CASTOR casks, and the radiation exposure of personnel.

    PubMed

    Bentele, W; Kinzelmann, T

    1999-12-01

    In 1997 and 1998, six spent fuel assembly transports started from the nuclear power plant Gemeinschaftskernkraftwerk Neckar (GKN), using CASTOR-V19 casks. Professor Kuni of Marburg University challenged the statement made by the German Federal Office for Radiation Protection (Bundesamt für Strahlenschutz (BfS)) based on accepted scientific knowledge, according to which so-called CASTOR transports present no risk, either to the population or to the escorting police units. This paper shows that the collective dose during the loading of the CASTOR casks amounted to 4.5 mSv (gamma and neutrons) per cask at the most, and that the maximum individual dose amounted to 0.26 mSv. In addition to these doses, the collective dose during handling and transport must be considered: this amounted to 0.35 mSv (gamma and neutrons). The dose to the police escort was <0.1 mSv (gamma and neutrons). In the light of these circumstances, this report is presented on contamination determined during the transport of CASTOR casks and of other spent fuel casks. The controls of spent fuel transports carried out since 1978, mainly with NTL 11 spent fuel casks, revealed that about one fifth of the transport casks which left the GKN with a surface contamination of <4 Bq cm(-2) (limit for surface contamination), presented degrees of contamination >4 Bq cm(-2) upon reaching the Valognes/Cogema terminal. However, transport casks coming from French plants also revealed degrees of contamination >4 Bq cm(-2), as well as 'hot spots'. No such contamination was found on NTL 11 casks transported from the GKN to Sellafield. Neither was any increased contamination found upon the arrival of CASTOR-V19 casks transported from GKN to Gorleben or Ahaus. The partially sensationalist media reports were inversely proportional to the actual radiological relevance of the matter. The German Commission on Radiation Protection (SSK) confirmed that the radiological effect of such contaminated spent fuel transports is

  2. Advances in NASA radiation transport research: 3DHZETRN

    NASA Astrophysics Data System (ADS)

    Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

    2014-07-01

    The computationally efficient HZETRN code has been used in recent trade studies for lunar and Martian exploration and is currently being used in the engineering development of the next generation of space vehicles, habitats, and extra vehicular activity equipment. Code development has been based on a progression of approximations first assuming all particles are produced in the initiator direction of incidence (straight-ahead) later improved by treating neutrons produced in the backward hemisphere as moving straight-back (bi-directional). A new version (3DHZETRN) capable of transporting High charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation in transverse directions is developed. Herein, new algorithms for light ion and neutron propagation with well defined convergence criteria in 3D objects is developed and tested against Monte Carlo simulations of 3D effects.

  3. Dust Transport, Deposition and Radiative Effects Observed from MODIS

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Koren, I.; Remer, L. A.; Tanre, D.; Ginoux, P.; Fan, S.

    2003-01-01

    Carlson (1977) used satellite (AVHRR) observation of dust episodes 3 estimate that 90 tg of dust are emitted from Africa (0-30 N) to the Atlantic Ocean between June and August. MODIS systematic measurements of aerosol optical thickness (AOT) and the fraction of the AOT (f) due to the fine mode (see Remer et al abstract), are used to derive the column concentration, flux and deposition of African dust over the Atlantic Ocean. The main data set is for 2001 but the results are consistent with MODIS measurements from 2002. The analysis first determines the properties of maritime baseline aerosol (AOT=0.06, f=0.5); followed by linear scaling of the dust AOT and the anthropogenic AOT, based on MODIS measured values of the fraction "f" being 0.9 for anthropogenic aerosol and 0.5 for dust. NCEP winds are used in the analysis and are evaluated against observed dust movements between the Terra and Aqua passes (see Koren et al. abstract). Monthly values of dust transport and deposition are calculated. Preliminary results show that 280 tg of dust are emitted annually from Africa to the Atlantic Ocean between 20s and 30N, with 40 tg returning to Africa and Europe between 30N and 50N. 85 tg reach the Americas, with 130-150 tg are deposited in the Atlantic Ocean. The results are compared with dust transport models that indicate 110-230 tg of dust being deposited in the Ocean. It is interesting to note that the early estimates of Carlson (1977) and Carlson & Prosper0 (1972) are very close to our estimate from MODIS of 100 tg for the same latitude range and monthly period.

  4. Natural Attenuation of Anthropogenic Chromium in Selected Puye Formation in Regional Aquifer System of LOS Alamos, New Mexico

    NASA Astrophysics Data System (ADS)

    Brown, D. B.; Ding, M.; WoldeGabriel, G. W.; Cheshire, M.; Rearick, M.; Conradson, S.; Kluk, E.; Katzman, D.

    2014-12-01

    Routine groundwater monitoring conducted in 2005 revealed significant chromium (Cr) contamination in regional groundwater in Los Alamos, New Mexico. Previous use of potassium dichromate (K2Cr2O7) in cooling towers at Los Alamos National Laboratory's main power plant is believed to be the source of the elevated chromium levels. From 1956 to 1972 between 31,000 and 72,000 Kg of toxic Cr(IV) was released into Sandia Canyon. Initial investigations of the vadose zone using chromium isotopes indicated that reduction of anthropogenic Cr(IV) had occurred. However, to justify the use of Monitoring Natural Attenuation (MNA) as a valid remediation strategy, the Cr attenuation mechanism and the reduction capacity of the regional aquifer needs to be determined. Conventional batch sorption and synchrotron-based X-ray absorption spectroscopy studies were performed. Two samples were selected from the Puye formation, a silicoclastic sedimentary rock sequence located within the contaminated aquifer. Additionally, two Los Alamos Puye outcrop samples with no chromium exposure were selected for comparison. Each sample was subsequently sorted based on grain size, magnetic, and clay fractions. Groundwater with a known concentration of Cr(IV) was used in the batch experiments. Spectroscopy measurements of Puye samples before and after exposure to the same contaminated groundwater were conducted at the Stanford Synchrotron Radiation Lightsource (SSRL). Batch sorption results indicated little to no attenuation, as indicated by the small measured sorption coefficient (Kd < 5 Kg/L). Spectroscopic measurements suggest that attenuation of hexavalent chromium in groundwater is due to reduction of Cr(VI) to Cr(III) in the Puye and may be attributed almost exclusively to the clay fraction. These results indicate that the tested Puye sediments occurring in the regional aquifer have minor ability to naturally attenuate anthropogenic Cr(IV), with the clay fraction dominating the reduction process

  5. Applications Of Monte Carlo Radiation Transport Simulation Techniques For Predicting Single Event Effects In Microelectronics

    SciTech Connect

    Warren, Kevin; Reed, Robert; Weller, Robert; Mendenhall, Marcus; Sierawski, Brian; Schrimpf, Ronald

    2011-06-01

    MRED (Monte Carlo Radiative Energy Deposition) is Vanderbilt University's Geant4 application for simulating radiation events in semiconductors. Geant4 is comprised of the best available computational physics models for the transport of radiation through matter. In addition to basic radiation transport physics contained in the Geant4 core, MRED has the capability to track energy loss in tetrahedral geometric objects, includes a cross section biasing and track weighting technique for variance reduction, and additional features relevant to semiconductor device applications. The crucial element of predicting Single Event Upset (SEU) parameters using radiation transport software is the creation of a dosimetry model that accurately approximates the net collected charge at transistor contacts as a function of deposited energy. The dosimetry technique described here is the multiple sensitive volume (MSV) model. It is shown to be a reasonable approximation of the charge collection process and its parameters can be calibrated to experimental measurements of SEU cross sections. The MSV model, within the framework of MRED, is examined for heavy ion and high-energy proton SEU measurements of a static random access memory.

  6. Prototype demonstration of radiation therapy planning code system

    SciTech Connect

    Little, R.C.; Adams, K.J.; Estes, G.P.; Hughes, L.S. III; Waters, L.S.

    1996-09-01

    This is the final report of a one-year, Laboratory-Directed Research and Development project at the Los Alamos National Laboratory (LANL). Radiation therapy planning is the process by which a radiation oncologist plans a treatment protocol for a patient preparing to undergo radiation therapy. The objective is to develop a protocol that delivers sufficient radiation dose to the entire tumor volume, while minimizing dose to healthy tissue. Radiation therapy planning, as currently practiced in the field, suffers from inaccuracies made in modeling patient anatomy and radiation transport. This project investigated the ability to automatically model patient-specific, three-dimensional (3-D) geometries in advanced Los Alamos radiation transport codes (such as MCNP), and to efficiently generate accurate radiation dose profiles in these geometries via sophisticated physics modeling. Modem scientific visualization techniques were utilized. The long-term goal is that such a system could be used by a non-expert in a distributed computing environment to help plan the treatment protocol for any candidate radiation source. The improved accuracy offered by such a system promises increased efficacy and reduced costs for this important aspect of health care.

  7. New approach to the solution of the Boltzmann radiation transport equation

    NASA Astrophysics Data System (ADS)

    Boffi, Vinicio C.; Dunn, William L.

    1987-03-01

    Transport monodimensional stationary solutions for the angular space-energy neutron flux, of interest in radiation penetration problems, are studied by Green's function method. Explicit analytical results for the spatial moments of the sought solution are obtained for the case of an isotropically scattering slab of infinite thickness and of a continuous slowing down model in energy.

  8. The use of symbolic computation in radiative, energy, and neutron transport calculations. Final report

    SciTech Connect

    Frankel, J.I.

    1997-09-01

    This investigation used sysmbolic manipulation in developing analytical methods and general computational strategies for solving both linear and nonlinear, regular and singular integral and integro-differential equations which appear in radiative and mixed-mode energy transport. Contained in this report are seven papers which present the technical results as individual modules.

  9. Benchmarking Space Radiation Transport Codes Using Measured LET Spectra from the Crater Instrument on LRO

    NASA Astrophysics Data System (ADS)

    Townsend, L. W.; Porter, J.; Spence, H. E.; Golightly, M. J.; Smith, S. S.; Schwadron, N.; Kasper, J. C.; Case, A. W.; Blake, J. B.; Mazur, J. E.; Looper, M. D.; Zeitlin, C. J.

    2014-12-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft measures the energy depositions by solar and galactic cosmic radiations in its silicon detectors. These energy depositions are converted to linear energy transfer (LET) spectra, which can contribute to benchmarking space radiation transport codes and also used to estimate doses for the Lunar environment. In this work the Monte Carlo transport code HETC-HEDS (High Energy Transport Code - Human Exploration and Development in Space) and the deterministic NASA space radiation transport code HZETRN2010 are used to estimate LET and dose contributions from the incident primary ions and their charged secondaries produced in nuclear collisions within the components of the CRaTER instrument. Comparisons of the calculated LET spectra with measurements of LET from the CRaTER instrument are made and clearly show the importance of including corrections to the calculated average energy deposition spectra in the silicon detectors using a Vavilov distribution function.

  10. Radiation inactivation studies on the rabbit kidney sodium-dependent glucose transporter.

    PubMed

    Takahashi, M; Malathi, P; Preiser, H; Jung, C Y

    1985-09-05

    Rabbit kidney cortical brush-border membrane vesicles were irradiated in the frozen state with increasing doses of high energy electrons from a Van de Graaff generator. Sodium-dependent D-glucose and L-alanine transport showed a simple exponential loss of activity with increasing radiation dosage. Target size calculation based on these data gives estimates of 1.0 X 10(6) daltons for the glucose transporter and 1.2 X 10(6) daltons for the alanine transporter. A highly purified glucose transport protein extracted from rabbit kidney cortex was similarly irradiated both before and after reconstitution into liposomes. The target size of this purified glucose transporter was 343,000 daltons, based on inactivation of transport. The intensity of the major 165,000-dalton sodium dodecyl sulfate-gel electrophoresis band of this preparation was decreased by radiation. The decrease in staining intensity was dose-dependent, yielding a target size of 298,000 daltons, in situ. We propose that the purified glucose transporter reconstituted into liposomes is a tetramer comprised of 85,000-dalton subunits.

  11. Measurements on the shuttle of the LET spectra of galactic cosmic radiation and comparison with the radiation transport model

    SciTech Connect

    Badhwar, G.D.; Konradi, A.; Cucinotta, F.A.; Braby, L.A.

    1994-09-01

    A new class of tissue-equivalent proportional counters has been flown on two space shuttle flights. These detectors and their associated electronics cover a lineal energy range from 0.4 to 1250 keV/{mu}m with a multichannel analyzer resolution of 0.1 keV/{mu}m from 0.4 to 20 keV/{mu} and 5 keV/{mu}m from 20 to 1250 keV/{mu}m. These detectors provide the most complete dynamic range and highest resolution of any technique currently in use. On one mission, one detector was mounted in the Shuttle payload bay and another older modele in the mid-deck, thus providing information on the depth dependence of the lineal energy spectrum. A detailed comparison of the observed lineal energy and calculated LET spectra for galacic cosmic radiation shows that, although the radiation transport models provide a rather accurate description of the dose ({+-}15%) and equivalent dose ({+-}15%), the calculations significantly underestimate the frequency of events below about 100 keV/{mu}m. This difference cannot be explained by the inclusion of the contribution of splash protons. The contribution of the secondary pions, kaons and electrons produce in the Shuttle shielding, if included in the radiation transport model, may explain these differences. There are also significant differences between the model predictions and observations above 1440 keV/{mu}m, particularly for 28.5{degrees} inclination orbit. 24 refs., 9 figs., 1 tab.

  12. 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

  13. Comparison of Stopping Power and Range Databases for Radiation Transport Study

    NASA Technical Reports Server (NTRS)

    Tai, H.; Bichsel, Hans; Wilson, John W.; Shinn, Judy L.; Cucinotta, Francis A.; Badavi, Francis F.

    1997-01-01

    The codes used to calculate stopping power and range for the space radiation shielding program at the Langley Research Center are based on the work of Ziegler but with modifications. As more experience is gained from experiments at heavy ion accelerators, prudence dictates a reevaluation of the current databases. Numerical values of stopping power and range calculated from four different codes currently in use are presented for selected ions and materials in the energy domain suitable for space radiation transport. This study of radiation transport has found that for most collision systems and for intermediate particle energies, agreement is less than 1 percent, in general, among all the codes. However, greater discrepancies are seen for heavy systems, especially at low particle energies.

  14. Atmospheric Ionizing Radiation and the High Speed Civil Transport. Chapter 1

    NASA Technical Reports Server (NTRS)

    Maiden, D. L.; Wilson, J. W.; Jones, I. W.; Goldhagen, P.

    2003-01-01

    Atmospheric ionizing radiation is produced by extraterrestrial radiations incident on the Earth's atmosphere. These extraterrestrial radiations are of two sources: ever present galactic cosmic rays with origin outside the solar system and transient solar particle events that are at times very intense events associated with solar activity lasting several hours to a few days. Although the galactic radiation penetrating through the atmosphere to the ground is low in intensity, the intensity is more than two orders of magnitude greater at commercial aircraft altitudes. The radiation levels at the higher altitudes of the High Speed Civil Transport (HSCT) are an additional factor of two higher. Ionizing radiation produces chemically active radicals in biological tissues that alter the cell function or result in cell death. Protection standards against low levels of ionizing radiation are based on limitation of excess cancer mortality or limitation of developmental injury resulting in permanent damage to the offspring during pregnancy. The crews of commercial air transport operations are considered as radiation workers by the EPA, the FAA, and the International Commission on Radiological Protection (ICRP). The annual exposures of aircrews depend on the latitudes and altitudes of operation and flight time. Flight hours have significantly increased since deregulation of the airline industry in the 1980's. The FAA estimates annual subsonic aircrew exposures to range from 0.2 to 9.1 mSv compared to 0.5 mSv exposure of the average nuclear power plant worker in the nuclear industry. The commercial aircrews of the HSCT may receive exposures above recently recommended allowable limits for even radiation workers if flying their allowable number of flight hours. An adequate protection philosophy for background exposures in HSCT commercial airtraffic cannot be developed at this time due to current uncertainty in environmental levels. In addition, if a large solar particle event

  15. Radiation Transport Properties of Potential In Situ-Developed Regolith-Epoxy Materials for Martian Habitats

    NASA Technical Reports Server (NTRS)

    Miller, Jack; Heilbronn, Lawrence H.; Zeitlin, Cary J.; Wilson, John W.; Singleterry, Robert C., Jr.; Thibeault, Sheila Ann

    2003-01-01

    Mission crews in space outside the Earth s magnetic field will be exposed to high energy heavy charged particles in the galactic cosmic radiation (GCR). These highly ionizing particles will be a source of radiation risk to crews on extended missions to the Moon and Mars, and the biological effects of and countermeasures to the GCR have to be investigated as part of the planning of exploration-class missions. While it is impractical to shield spacecraft and planetary habitats against the entire GCR spectrum, biological and physical studies indicate that relatively modest amounts of shielding are effective at reducing the radiation dose. However, nuclear fragmentation in the shielding materials produces highly penetrating secondary particles, which complicates the problem: in some cases, some shielding is worse than none at all. Therefore the radiation transport properties of potential shielding materials need to be carefully investigated. One intriguing option for a Mars mission is the use of material from the Martian surface, in combination with chemicals carried from Earth and/or fabricated from elements found in the Martian atmosphere, to construct crew habitats. We have measured the transmission properties of epoxy-Martian regolith composites with respect to heavy charged particles characteristic of the GCR ions which bombard the Martian surface. The composites were prepared at NASA Langley Research Center using simulated Martian regolith, in the process also evaluating fabrication methods which could lead to technologies for in situ fabrication on Mars. Initial evaluation of the radiation shielding properties is made using radiation transport models developed at NASA-LaRC, and the results of these calculations are used to select the composites with the most favorable radiation transmission properties. These candidates are then evaluated at particle accelerators which produce beams of heavy charged particles representative in energy and charge of the radiation

  16. Solar radiation transport in the cloudy atmosphere: a 3D perspective on observations and climate impacts

    NASA Astrophysics Data System (ADS)

    Davis, Anthony B.; Marshak, Alexander

    2010-02-01

    The interplay of sunlight with clouds is a ubiquitous and often pleasant visual experience, but it conjures up major challenges for weather, climate, environmental science and beyond. Those engaged in the characterization of clouds (and the clear air nearby) by remote sensing methods are even more confronted. The problem comes, on the one hand, from the spatial complexity of real clouds and, on the other hand, from the dominance of multiple scattering in the radiation transport. The former ingredient contrasts sharply with the still popular representation of clouds as homogeneous plane-parallel slabs for the purposes of radiative transfer computations. In typical cloud scenes the opposite asymptotic transport regimes of diffusion and ballistic propagation coexist. We survey the three-dimensional (3D) atmospheric radiative transfer literature over the past 50 years and identify three concurrent and intertwining thrusts: first, how to assess the damage (bias) caused by 3D effects in the operational 1D radiative transfer models? Second, how to mitigate this damage? Finally, can we exploit 3D radiative transfer phenomena to innovate observation methods and technologies? We quickly realize that the smallest scale resolved computationally or observationally may be artificial but is nonetheless a key quantity that separates the 3D radiative transfer solutions into two broad and complementary classes: stochastic and deterministic. Both approaches draw on classic and contemporary statistical, mathematical and computational physics.

  17. Solar Radiation Transport in the Cloudy Atmosphere: A 3D Perspective on Observations and Climate Impacts

    NASA Technical Reports Server (NTRS)

    Davis, Anthony B.; Marshak, Alexander

    2010-01-01

    The interplay of sunlight with clouds is a ubiquitous and often pleasant visual experience, but it conjures up major challenges for weather, climate, environmental science and beyond. Those engaged in the characterization of clouds (and the clear air nearby) by remote sensing methods are even more confronted. The problem comes, on the one hand, from the spatial complexity of real clouds and, on the other hand, from the dominance of multiple scattering in the radiation transport. The former ingredient contrasts sharply with the still popular representation of clouds as homogeneous plane-parallel slabs for the purposes of radiative transfer computations. In typical cloud scenes the opposite asymptotic transport regimes of diffusion and ballistic propagation coexist. We survey the three-dimensional (3D) atmospheric radiative transfer literature over the past 50 years and identify three concurrent and intertwining thrusts: first, how to assess the damage (bias) caused by 3D effects in the operational 1D radiative transfer models? Second, how to mitigate this damage? Finally, can we exploit 3D radiative transfer phenomena to innovate observation methods and technologies? We quickly realize that the smallest scale resolved computationally or observationally may be artificial but is nonetheless a key quantity that separates the 3D radiative transfer solutions into two broad and complementary classes: stochastic and deterministic. Both approaches draw on classic and contemporary statistical, mathematical and computational physics.

  18. A hybrid transport-diffusion model for radiative transfer in absorbing and scattering media

    NASA Astrophysics Data System (ADS)

    Roger, M.; Caliot, C.; Crouseilles, N.; Coelho, P. J.

    2014-10-01

    A new multi-scale hybrid transport-diffusion model for radiative transfer is proposed in order to improve the efficiency of the calculations close to the diffusive regime, in absorbing and strongly scattering media. In this model, the radiative intensity is decomposed into a macroscopic component calculated by the diffusion equation, and a mesoscopic component. The transport equation for the mesoscopic component allows to correct the estimation of the diffusion equation, and then to obtain the solution of the linear radiative transfer equation. In this work, results are presented for stationary and transient radiative transfer cases, in examples which concern solar concentrated and optical tomography applications. The Monte Carlo and the discrete-ordinate methods are used to solve the mesoscopic equation. It is shown that the multi-scale model allows to improve the efficiency of the calculations when the medium is close to the diffusive regime. The proposed model is a good alternative for radiative transfer at the intermediate regime where the macroscopic diffusion equation is not accurate enough and the radiative transfer equation requires too much computational effort.

  19. Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays.

    PubMed

    Zygmanski, Piotr; Sajo, Erno

    2016-01-01

    We review radiation transport and clinical beam modelling for gold nanoparticle dose-enhanced radiotherapy using X-rays. We focus on the nanoscale radiation transport and its relation to macroscopic dosimetry for monoenergetic and clinical beams. Among other aspects, we discuss Monte Carlo and deterministic methods and their applications to predicting dose enhancement using various metrics.

  20. Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays

    PubMed Central

    Sajo, Erno

    2016-01-01

    We review radiation transport and clinical beam modelling for gold nanoparticle dose-enhanced radiotherapy using X-rays. We focus on the nanoscale radiation transport and its relation to macroscopic dosimetry for monoenergetic and clinical beams. Among other aspects, we discuss Monte Carlo and deterministic methods and their applications to predicting dose enhancement using various metrics. PMID:26642305

  1. Alterations in dose and lineal energy spectra under different shieldings in the Los Alamos high-energy neutron field

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Huff, H.; Wilkins, R.

    2000-01-01

    Nuclear interactions of space radiation with shielding materials result in alterations in dose and lineal energy spectra that depend on the specific elemental composition, density and thickness of the material. The shielding characteristics of materials have been studied using charged-particle beams and radiation transport models by examining the risk reduction using the conventional dose-equivalent approach. Secondary neutrons contribute a significant fraction of the total radiation exposure in space. An experiment to study the changes in dose and lineal energy spectra by shielding materials was carried out at the Los Alamos Nuclear Science Center neutron facility. In the energy range of about 2 to 200 MeV, this neutron spectrum is similar in shape within a factor of about 2 to the spectrum expected in the International Space Station habitable modules. It is shown that with a shielding thickness of about 5 g cm(-2), the conventional radiation risk increases, in some cases by as much as a factor of 2, but decreases with thicknesses of about of 20 g cm(-2). This suggests that care must be taken in evaluating the shielding effectiveness of a given material by including both the charged-particle and neutron components of space radiation.

  2. Sunset at the ALaMO

    NASA Video Gallery

    A new color all-sky camera has opened its eyes at the ALaMO, or Automated Lunar and Meteor Observatory, at NASA's Marshall Space Flight Center in Huntsville, Ala. Watch its inaugural video below, s...

  3. Publications of Los Alamos research 1988

    SciTech Connect

    Varjabedian, K.; Dussart, S.A.; McClary, W.J.; Rich, J.A.

    1989-12-01

    This bibliography lists unclassified publications of work done at the Los Alamos National Laboratory for 1988. The entries, which are subdivided by broad subject categories, are cross-referenced with an author index and a numeric index.

  4. New Rad Lab for Los Alamos

    ScienceCinema

    None

    2016-07-12

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  5. New Rad Lab for Los Alamos

    SciTech Connect

    2008-08-06

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  6. Calculation of radiation therapy dose using all particle Monte Carlo transport

    DOEpatents

    Chandler, W.P.; Hartmann-Siantar, C.L.; Rathkopf, J.A.

    1999-02-09

    The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media. 57 figs.

  7. Calculation of radiation therapy dose using all particle Monte Carlo transport

    DOEpatents

    Chandler, William P.; Hartmann-Siantar, Christine L.; Rathkopf, James A.

    1999-01-01

    The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

  8. Asymptotic diffusion limit of cell temperature discretisation schemes for thermal radiation transport

    SciTech Connect

    Smedley-Stevenson, Richard P.; McClarren, Ryan G.

    2015-04-01

    This paper attempts to unify the asymptotic diffusion limit analysis of thermal radiation transport schemes, for a linear-discontinuous representation of the material temperature reconstructed from cell centred temperature unknowns, in a process known as ‘source tilting’. The asymptotic limits of both Monte Carlo (continuous in space) and deterministic approaches (based on linear-discontinuous finite elements) for solving the transport equation are investigated in slab geometry. The resulting discrete diffusion equations are found to have nonphysical terms that are proportional to any cell-edge discontinuity in the temperature representation. Based on this analysis it is possible to design accurate schemes for representing the material temperature, for coupling thermal radiation transport codes to a cell centred representation of internal energy favoured by ALE (arbitrary Lagrange–Eulerian) hydrodynamics schemes.

  9. Edward Teller Returns to LOS Alamos

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2010-01-01

    I was asked to share some reflections of Edward Teller's return to Los Alamos during my directorship. I met Teller late in his life. My comments focus on that time and they will be mostly in the form of stories of my interactions and those of my colleagues with Teller. Although the focus of this symposium is on Teller's contributions to science, at Los Alamos it was never possible to separate Teller's science from policy and controversy ...

  10. Internship at Los Alamos National Laboratory

    SciTech Connect

    Dunham, Ryan Q.

    2012-07-11

    Los Alamos National Laboratory (LANL) is located in Los Alamos, New Mexico. It provides support for our country's nuclear weapon stockpile as well as many other scientific research projects. I am an Undergraduate Student Intern in the Systems Design and Analysis group within the Nuclear Nonproliferation division of the Global Security directorate at LANL. I have been tasked with data analysis and modeling of particles in a fluidized bed system for the capture of carbon dioxide from power plant flue gas.

  11. Los Alamos Laser Eye Investigation.

    SciTech Connect

    Odom, C. R.

    2005-01-01

    A student working in a laser laboratory at Los Alamos National Laboratory sustained a serious retinal injury to her left eye when she attempted to view suspended particles in a partially evacuated target chamber. The principle investigator was using the white light from the flash lamp of a Class 4 Nd:YAG laser to illuminate the particles. Since the Q-switch was thought to be disabled at the time of the accident, the principal investigator assumed it would be safe to view the particles without wearing laser eye protection. The Laboratory Director appointed a team to investigate the accident and to report back to him the events and conditions leading up to the accident, equipment malfunctions, safety management causal factors, supervisory and management action/inaction, adequacy of institutional processes and procedures, emergency and notification response, effectiveness of corrective actions and lessons learned from previous similar events, and recommendations for human and institutional safety improvements. The team interviewed personnel, reviewed documents, and characterized systems and conditions in the laser laboratory during an intense six week investigation. The team determined that the direct and primary failures leading to this accident were, respectively, the principle investigator's unsafe work practices and the institution's inadequate monitoring of worker performance. This paper describes the details of the investigation, the human and institutional failures, and the recommendations for improving the laser safety program.

  12. Los Alamos Neutron Science Center

    SciTech Connect

    Kippen, Karen Elizabeth

    2016-11-08

    For more than 30 years the Los Alamos Neutron Science Center (LANSCE) has provided the scientific underpinnings in nuclear physics and material science needed to ensure the safety and surety of the nuclear stockpile into the future. In addition to national security research, the LANSCE User Facility has a vibrant research program in fundamental science, providing the scientific community with intense sources of neutrons and protons to perform experiments supporting civilian research and the production of medical and research isotopes. Five major experimental facilities operate simultaneously. These facilities contribute to the stockpile stewardship program, produce radionuclides for medical testing, and provide a venue for industrial users to irradiate and test electronics. In addition, they perform fundamental research in nuclear physics, nuclear astrophysics, materials science, and many other areas. The LANSCE User Program plays a key role in training the next generation of top scientists and in attracting the best graduate students, postdoctoral researchers, and early-career scientists. The U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) —the principal sponsor of LANSCE—works with the Office of Science and the Office of Nuclear Energy, which have synergistic long-term needs for the linear accelerator and the neutron science that is the heart of LANSCE.

  13. Non-equilibrium Landauer transport model for Hawking radiation from a black hole

    NASA Astrophysics Data System (ADS)

    Nation, P. D.; Blencowe, M. P.; Nori, Franco

    2012-03-01

    We propose that the Hawking radiation energy and entropy flow rates from a black hole can be viewed as a one-dimensional (1D), non-equilibrium Landauer transport process. Support for this viewpoint comes from previous calculations invoking conformal symmetry in the near-horizon region, which give radiation rates that are identical to those of a single 1D quantum channel connected to a thermal reservoir at the Hawking temperature. The Landauer approach shows in a direct way the particle statistics independence of the energy and entropy fluxes of a black hole radiating into vacuum, as well as one near thermal equilibrium with its environment. As an application of the Landauer approach, we show that Hawking radiation gives a net entropy production that is 50% larger than that obtained assuming standard 3D emission into vacuum.

  14. On the Transport and Radiative Properties of Plasmas with Small-Scale Electromagnetic Fluctuations

    NASA Astrophysics Data System (ADS)

    Keenan, Brett D.

    Plasmas with sub-Larmor-scale ("small-scale") electromagnetic fluctuations are a feature of a wide variety of high-energy-density environments, and are essential to the description of many astrophysical/laboratory plasma phenomena. Radiation from particles, whether they be relativistic or non-relativistic, moving through small-scale electromagnetic turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation. The radiation, carrying information on the statistical properties of the turbulence, is also intimately related to the particle diffusive transport. We investigate, both theoretically and numerically, the transport of non-relativistic and transrelativistic particles in plasmas with high-amplitude isotropic sub-Larmor-scale magnetic turbulence---both with and without a mean field component---and its relation to the spectra of radiation simultaneously produced by these particles. Furthermore, the transport of particles through small-scale electromagnetic turbulence---under certain conditions---resembles the random transport of particles---via Coulomb collisions---in collisional plasmas. The pitch-angle diffusion coefficient, which acts as an effective "collision" frequency, may be substantial in these, otherwise, collisionless environments. We show that this effect, colloquially referred to as the plasma "quasi-collisionality", may radically alter the expected radiative transport properties of candidate plasmas. We argue that the modified magneto-optic effects in these plasmas provide an attractive, novel, diagnostic tool for the exploration and characterization of small-scale electromagnetic turbulence. Lastly, we speculate upon the manner in which quasi-collisions may affect inertial confinement fusion (ICF), and other laser-plasma experiments. Finally, we show that mildly relativistic jitter radiation, from laser-produced plasmas, may offer insight into the underlying electromagnetic turbulence. Here we investigate the

  15. A Note on the Radiative and Collisional Branching Ratios in Polarized Radiation Transport with Coherent Scattering

    NASA Astrophysics Data System (ADS)

    Casini, R.; del Pino Alemán, T.; Manso Sainz, R.

    2017-02-01

    We discuss the implementation of physically meaningful branching ratios between the CRD and partial redistribution contributions to the emissivity of a polarized multi-term atom in the presence of both inelastic and elastic collisions. Our derivation is based on a recent theoretical formulation of partially coherent scattering, and it relies on a heuristic diagrammatic analysis of the various radiative and collisional processes to determine the proper form of the branching ratios. The expression we obtain for the emissivity is {\\boldsymbol{\\varepsilon }}=[{{\\boldsymbol{\\varepsilon }}}(1)-{{\\boldsymbol{\\varepsilon }}}{{f}.{{s}}.}(2)]+{{\\boldsymbol{\\varepsilon }}}(2), where {{\\boldsymbol{\\varepsilon }}}(1) and {{\\boldsymbol{\\varepsilon }}}(2) are the emissivity terms for the redistributed and partially coherent radiation, respectively, and where “f.s.” implies that the corresponding term must be evaluated assuming a flat-spectrum average of the incident radiation. This result is shown to be in agreement with prior literature on the subject in the limit of the unpolarized multi-level atom.

  16. Status of the solar and infrared radiation submodels in the LLNL 1-D and 2-D chemical-transport models

    SciTech Connect

    Grant, K.E.; Taylor, K.E.; Ellis, J.S.; Wuebbles, D.J.

    1987-07-01

    The authors have implemented a series of state of the art radiation transport submodels in previously developed one dimensional and two dimensional chemical transport models of the troposphere and stratosphere. These submodels provide the capability of calculating accurate solar and infrared heating rates. They are a firm basis for further radiation submodel development as well as for studying interactions between radiation and model dynamics under varying conditions of clear sky, clouds, and aerosols. 37 refs., 3 figs.

  17. Tiger Team Assessment of the Los Alamos National Laboratory

    SciTech Connect

    Not Available

    1991-11-01

    The purpose of the safety and health assessment was to determine the effectiveness of representative safety and health programs at the Los Alamos National Laboratory (LANL). Within the safety and health programs at LANL, performance was assessed in the following technical areas: Organization and Administration, Quality Verification, Operations, Maintenance, Training and Certification, Auxiliary Systems, Emergency Preparedness, Technical Support, Packaging and Transportation, Nuclear Criticality Safety, Security/Safety Interface, Experimental Activities, Site/Facility Safety Review, Radiological Protection, Personnel Protection, Worker Safety and Health (OSHA) Compliance, Fire Protection, Aviation Safety, Explosives Safety, Natural Phenomena, and Medical Services.

  18. Using TLDs to monitor Los Alamos drillbacks at the Nevada test site

    SciTech Connect

    Cucchiara, A.L.; Martin, A.

    1985-01-01

    Los Alamos National Laboratory uses LiF TLDs to measure the quantity of radiation in the environment during drilling, sampling and hole cementing operations following underground nuclear testing. The procedures for preparing the TLDs, placing the TLDs in the field and their subsequent analysis and dose evaluation are presented. 5 references, 4 figures, 1 table.

  19. Produce and fish sampling program of Los Alamos National Laboratory's Environmental Surveillance Group

    SciTech Connect

    Salazar, J.G.

    1984-09-01

    This report describes produce and fish sampling procedures of the Environmental Surveillance Group at the Los Alamos National Laboratory. The program monitors foodstuffs and fish for possible radioactive contamination from Laboratory operations. Data gathered in this program on radionuclide concentrations help to estimate radiation doses to Laboratory personnel and the public. 3 references, 7 figures, 2 tables.

  20. Transport simulations of a density limit in radiation-dominated tokamak discharges: Profile effects

    SciTech Connect

    Stotler, D.P.

    1988-06-01

    The density limit observed in tokamak experiments is thought to be due to a radiative collapse of the current channel. A transport code coupled with an MHD equilibrium routine is used to determine the detailed, self-consistent evolution of the plasma profiles in tokamak discharges with radiated power close to or equalling the input power. The present work is confined to ohmic discharges in steady state. It is found that the shape of the density profile can have a significant impact on the variation of the maximum electron density with plasma current. Analytic calculations confirm this result. 41 refs., 9 figs.

  1. Observation of subsonic and supersonic radiation fronts on OMEGA utilizing radiation transport through Sc-doped aerogels

    NASA Astrophysics Data System (ADS)

    Johns, H. M.; Kline, J.; Lanier, N.; Perry, T.; Fontes, C.; Fryer, C.; Brown, C.; Morton, J.; Hager, J.

    2016-10-01

    The propagation of a heat front in an astrophysical or inertial confinement fusion plasma involves both the equation of state and the opacity of the plasma, and is therefore an important and challenging radiation transport problem. Past experiments have used absorption spectroscopy in chlorinated foams to measure the heat front. (D. Hoarty et al. PRL 82, 3070, 1999). Recent development of Ti-doped cylindrical aerogel foam targets (J. Hager et al. submitted to RSI) results in a more suitable platform for higher temperatures on NIF than Cl dopant. Ti K-shell absorption spectra can be modeled with PrismSPECT to obtain spatially resolved temperature profiles between 100-180eV. Sc dopant has been selected to characterize the heat front between 60-100eV. Improved understanding of non-planckian x-ray drives generated by hohlraums will advance characterization of the radiation transport. Prior work demonstrates PrismSPECT with OPLIB is more physically complete for Sc (H. Johns et al. submitted to RSI). We will present the first application of spectroscopic analysis of the Sc-doped aerogels utilizing this method. This work performed under the auspices of the U.S. Department of Energy by LANL under contract DE-AC52-06NA25396.

  2. Gray and multigroup radiation transport models for two-dimensional binary stochastic media using effective opacities

    DOE PAGES

    Olson, Gordon L.

    2015-09-24

    One-dimensional models for the transport of radiation through binary stochastic media do not work in multi-dimensions. In addition, authors have attempted to modify or extend the 1D models to work in multidimensions without success. Analytic one-dimensional models are successful in 1D only when assuming greatly simplified physics. State of the art theories for stochastic media radiation transport do not address multi-dimensions and temperature-dependent physics coefficients. Here, the concept of effective opacities and effective heat capacities is found to well represent the ensemble averaged transport solutions in cases with gray or multigroup temperature-dependent opacities and constant or temperature-dependent heat capacities. Inmore » every case analyzed here, effective physics coefficients fit the transport solutions over a useful range of parameter space. The transport equation is solved with the spherical harmonics method with angle orders of n=1 and 5. Although the details depend on what order of solution is used, the general results are similar, independent of angular order.« less

  3. Analysis of radiation doses from operation of postulated commercial spent fuel transportation systems: Main report

    SciTech Connect

    Schneider, K.J.; Hostick, C.J.; Ross, W.A.; Peterson, R.W.; Smith, R.I.; Stiles, D.L.; Daling, P.M.; Weakley, S.A.; Grinde, R.B.; Young, J.R.

    1987-11-01

    This report contains a system study of estimated radiation doses to the public and workers resulting from the transport of spent fuel from commercial nuclear power reactors to a geologic repository. The report contains a detailed breakdown of activities and a description of time/distance/dose-rate estimates for each activity within the system. Collective doses are estimated for each of the major activities at the reactor site, in transit, and at the repository receiving facility. Annual individual doses to the maximally exposed individuals or groups of individuals are also estimated. A total of 17 alternatives and subalternatives to the postulated reference transportation system are identified, conceptualized, and their dose-reduction potentials and costs estimated. Resulting ratios of ..delta..cost/..delta..collective system dose for each alternative relative to the postulated reference transportation system are given. Most of the alternatives evaluated are estimated to provide both cost and dose reductions. Major reductions in transportation system dose and cost are estimated to result from using higher-capacity rail and truck casks, and particularly when replacing legalweight truck casks with ''advanced design'' overweight truck casks. The greatest annual dose reduction to the highest exposed individual workers (i.e., at the repository) is estimated to be achieved by using remote handling equipment for the cask handling operations at the repository. Additional shielding is also effective in reducing doses to both radiation workers at the reactor and repository and to transport workers. 69 refs., 36 figs., 156 tabs.

  4. Gray and multigroup radiation transport models for two-dimensional binary stochastic media using effective opacities

    SciTech Connect

    Olson, Gordon L.

    2015-09-24

    One-dimensional models for the transport of radiation through binary stochastic media do not work in multi-dimensions. In addition, authors have attempted to modify or extend the 1D models to work in multidimensions without success. Analytic one-dimensional models are successful in 1D only when assuming greatly simplified physics. State of the art theories for stochastic media radiation transport do not address multi-dimensions and temperature-dependent physics coefficients. Here, the concept of effective opacities and effective heat capacities is found to well represent the ensemble averaged transport solutions in cases with gray or multigroup temperature-dependent opacities and constant or temperature-dependent heat capacities. In every case analyzed here, effective physics coefficients fit the transport solutions over a useful range of parameter space. The transport equation is solved with the spherical harmonics method with angle orders of n=1 and 5. Although the details depend on what order of solution is used, the general results are similar, independent of angular order.

  5. Implementation of tetrahedral-mesh geometry in Monte Carlo radiation transport code PHITS.

    PubMed

    Furuta, Takuya; Sato, Tatsuhiko; Han, Min; Yeom, Yeon; Kim, Chan; Brown, Justin; Bolch, Wesley

    2017-04-04

    A new function to treat tetrahedral-mesh geometry was implemented in the Particle and Heavy Ion Transport code Systems (PHITS). To accelerate the computational speed in the transport process, an original algorithm was introduced to initially prepare decomposition maps for the container box of the tetrahedral-mesh geometry. The computational performance was tested by conducting radiation transport simulations of 100 MeV protons and 1 MeV photons in a water phantom represented by tetrahedral mesh. The simulation was repeated with varying number of meshes and the required computational times were then compared with those of the conventional voxel representation. Our results show that the computational costs for each boundary crossing of the region mesh are essentially equivalent for both representations. This study suggests that the tetrahedral-mesh representation offers not only a flexible description of the transport geometry but also improvement of computational efficiency for the radiation transport. Due to the adaptability of tetrahedrons in both size and shape, dosimetrically equivalent objects can be represented by tetrahedrons with a much fewer number of meshes as compared its voxelized representation. Our study additionally included dosimetric calculations using a computational human phantom. A significant acceleration of the computational speed, about 4 times, was confirmed by the adoption of a tetrahedral mesh over the traditional voxel mesh geometry.

  6. A coupled radiation transport-thermal analysis of the radiation shield for an SP-100 type reactor

    NASA Astrophysics Data System (ADS)

    Barattino, William J.; El-Genk, Mohamed S.; McDaniel, Patrick J.

    A coupled radiation transport-thermal analysis of the radiation shield for an SP-100 reactor was performed using finite element codes developed at the University of New Mexico and Sandia National Laboratories. For a fast reactor operating at 1.66 MWt, the energy deposited and resulting temperature distribution were determined for a shield consisting of tungsten and lithium hydride pressed into a stainless steel honeycomb matrix. While temperature feedback was shown to have a minor effect on energy deposition, the shielding configuration was found to have a major influence in meeting thermal requirements of the lithium hydride. It was shown that a shield optimized only for radiation protection will fail because of LiH melting. However, with minor modifications in the shield layering and material selection, the thermal integrity of the shield can be preserved. A shield design of graphite, depleted lithium hydride, tungsten, and natural lithium hydride was shown to satisfy neutron and gamma fluence requirements, and maximum temperature limits, and to minimize cracking in the LiH portion of the shield.

  7. A NEW MONTE CARLO METHOD FOR TIME-DEPENDENT NEUTRINO RADIATION TRANSPORT

    SciTech Connect

    Abdikamalov, Ernazar; Ott, Christian D.; O'Connor, Evan; Burrows, Adam; Dolence, Joshua C.; Loeffler, Frank; Schnetter, Erik

    2012-08-20

    Monte Carlo approaches to radiation transport have several attractive properties such as simplicity of implementation, high accuracy, and good parallel scaling. Moreover, Monte Carlo methods can handle complicated geometries and are relatively easy to extend to multiple spatial dimensions, which makes them potentially interesting in modeling complex multi-dimensional astrophysical phenomena such as core-collapse supernovae. The aim of this paper is to explore Monte Carlo methods for modeling neutrino transport in core-collapse supernovae. We generalize the Implicit Monte Carlo photon transport scheme of Fleck and Cummings and gray discrete-diffusion scheme of Densmore et al. to energy-, time-, and velocity-dependent neutrino transport. Using our 1D spherically-symmetric implementation, we show that, similar to the photon transport case, the implicit scheme enables significantly larger timesteps compared with explicit time discretization, without sacrificing accuracy, while the discrete-diffusion method leads to significant speed-ups at high optical depth. Our results suggest that a combination of spectral, velocity-dependent, Implicit Monte Carlo and discrete-diffusion Monte Carlo methods represents a robust approach for use in neutrino transport calculations in core-collapse supernovae. Our velocity-dependent scheme can easily be adapted to photon transport.

  8. Development of a hybrid kinetic-fluid model for line radiation transport in magnetic fusion plasmas

    NASA Astrophysics Data System (ADS)

    Rosato, J.; Marandet, Y.; Reiter, D.; Stamm, R.

    2017-03-01

    We report on a transport model for the Lyman line radiation in optically thick divertor plasma conditions encountered in exhaust systems in magnetic fusion devices. The model is designed to switch automatically between a kinetic and a continuum description according to the plasma conditions and to the spectral range. A kinetic treatment is retained for photons with a large mean free path (line wings), whereas a continuum description of the radiation field is invoked in highly absorbing or scattering regions (core photons). Prototypical calculations of this so-called δf Monte Carlo type of the Lyman α photo-excitation rate in slab geometry are performed as an illustration. The hybrid method is suggested as a candidate for speeding up the kinetic transport codes currently involved in magnetic fusion research for ITER and DEMO divertor (power and particle exhaust system) design.

  9. On MHD rotational transport, instabilities and dynamo action in stellar radiation zones

    NASA Astrophysics Data System (ADS)

    Mathis, Stéphane; Brun, A.-S.; Zahn, J.-P.

    2009-04-01

    Magnetic field and their related dynamical effects are thought to be important in stellar radiation zones. For instance, it has been suggested that a dynamo, sustained by a m = 1 MHD instability of toroidal magnetic fields (discovered by Tayler in 1973), could lead to a strong transport of angular momentum and of chemicals in such stable regions. We wish here to recall the different magnetic transport processes present in radiative zone and show how the dynamo can operate by recalling the conditions required to close the dynamo loop (BPol → BTor → BPol). Helped by high-resolution 3D MHD simulations using the ASH code in the solar case, we confirm the existence of the m = 1 instability, study its non-linear saturation, but we do not detect, up to a magnetic Reylnods number of 105, any dynamo action.

  10. Radiation Transport Around Axisymmetric Blunt Body Vehicles Using a Modified Differential Approximation

    NASA Technical Reports Server (NTRS)

    Hartung, Lin C.; Hassan, H. A.

    1992-01-01

    A moment method for computing 3-D radiative transport is applied to axisymmetric flows in thermochemical nonequilibrium. Such flows are representative of proposed aerobrake missions. The method uses the P-1 approximation to reduce the governing system of integro-di erential equations to a coupled set of partial di erential equations. A numerical solution method for these equations given actual variations of the radiation properties in thermochemical nonequilibrium blunt body flows is developed. Initial results from the method are shown and compared to tangent slab calculations. The agreement between the transport methods is found to be about 10 percent in the stagnation region, with the difference increasing along the flank of the vehicle.

  11. Implementation, capabilities, and benchmarking of Shift, a massively parallel Monte Carlo radiation transport code

    DOE PAGES

    Pandya, Tara M.; Johnson, Seth R.; Evans, Thomas M.; ...

    2015-12-21

    This paper discusses the implementation, capabilities, and validation of Shift, a massively parallel Monte Carlo radiation transport package developed and maintained at Oak Ridge National Laboratory. It has been developed to scale well from laptop to small computing clusters to advanced supercomputers. Special features of Shift include hybrid capabilities for variance reduction such as CADIS and FW-CADIS, and advanced parallel decomposition and tally methods optimized for scalability on supercomputing architectures. Shift has been validated and verified against various reactor physics benchmarks and compares well to other state-of-the-art Monte Carlo radiation transport codes such as MCNP5, CE KENO-VI, and OpenMC. Somemore » specific benchmarks used for verification and validation include the CASL VERA criticality test suite and several Westinghouse AP1000® problems. These benchmark and scaling studies show promising results.« less

  12. Implementation, capabilities, and benchmarking of Shift, a massively parallel Monte Carlo radiation transport code

    SciTech Connect

    Pandya, Tara M.; Johnson, Seth R.; Evans, Thomas M.; Davidson, Gregory G.; Hamilton, Steven P.; Godfrey, Andrew T.

    2015-12-21

    This paper discusses the implementation, capabilities, and validation of Shift, a massively parallel Monte Carlo radiation transport package developed and maintained at Oak Ridge National Laboratory. It has been developed to scale well from laptop to small computing clusters to advanced supercomputers. Special features of Shift include hybrid capabilities for variance reduction such as CADIS and FW-CADIS, and advanced parallel decomposition and tally methods optimized for scalability on supercomputing architectures. Shift has been validated and verified against various reactor physics benchmarks and compares well to other state-of-the-art Monte Carlo radiation transport codes such as MCNP5, CE KENO-VI, and OpenMC. Some specific benchmarks used for verification and validation include the CASL VERA criticality test suite and several Westinghouse AP1000® problems. These benchmark and scaling studies show promising results.

  13. A new spherical harmonics scheme for multi-dimensional radiation transport I. Static matter configurations

    SciTech Connect

    Radice, David; Abdikamalov, Ernazar; Rezzolla, Luciano; Ott, Christian D.

    2013-06-01

    Recent work by McClarren and Hauck (2010) [31] suggests that the filtered spherical harmonics method represents an efficient, robust, and accurate method for radiation transport, at least in the two-dimensional (2D) case. We extend their work to the three-dimensional (3D) case and find that all of the advantages of the filtering approach identified in 2D are present also in the 3D case. We reformulate the filter operation in a way that is independent of the timestep and of the spatial discretization. We also explore different second- and fourth-order filters and find that the second-order ones yield significantly better results. Overall, our findings suggest that the filtered spherical harmonics approach represents a very promising method for 3D radiation transport calculations.

  14. A Monte Carlo Code for Relativistic Radiation Transport Around Kerr Black Holes

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy David; Krolik, Julian H.

    2013-01-01

    We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.

  15. A MONTE CARLO CODE FOR RELATIVISTIC RADIATION TRANSPORT AROUND KERR BLACK HOLES

    SciTech Connect

    Schnittman, Jeremy D.; Krolik, Julian H. E-mail: jhk@pha.jhu.edu

    2013-11-01

    We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.

  16. Exact and efficient solution of the radiative transport equation for the semi-infinite medium

    NASA Astrophysics Data System (ADS)

    Liemert, André; Kienle, Alwin

    2013-06-01

    An accurate and efficient solution of the radiative transport equation is proposed for modeling the propagation of photons in the three-dimensional anisotropically scattering half-space medium. The exact refractive index mismatched boundary condition is considered and arbitrary rotationally invariant scattering functions can be applied. The obtained equations are verified with Monte Carlo simulations in the steady-state, temporal frequency, and time domains resulting in an excellent agreement.

  17. Environmental surveillance and compliance at Los Alamos during 1996

    SciTech Connect

    1997-09-01

    This report presents environmental data that characterize environmental performance and addresses compliance with environmental standards and requirements at Los Alamos National Laboratory (LANL or the Laboratory) during 1996. The Laboratory routinely monitors for radiation and for radioactive nonradioactive materials at Laboratory sites as well as in the surrounding region. LANL uses the monitoring results to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1996 to assess external penetrating radiation; quantities of airborne emissions; and concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, the municipal water supply, soils and sediments, and foodstuffs. Using comparisons with standards and regulations, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, Laboratory employees, or the environment. Laboratory operations were in compliance with all major environmental regulations.

  18. Environmental surveillance at Los Alamos during 1991. Environmental protection group

    SciTech Connect

    Dewart, J.; Kohen, K.L.

    1993-08-01

    This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1991. Routine monitoring for radiation and for radioactive and chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1991 cover external penetrating radiation; quantities of airborne emissions and effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriate standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are small and do not pose a threat to the public, Laboratory employees, or the environment.

  19. RCRA facility investigation for the townsite of Los Alamos, New Mexico

    SciTech Connect

    Dorries, A.M.; Conrad, R.C.; Nonno, L.M.

    1992-01-01

    During World War II, Los Alamos, New Mexico was established as an ideal location for the secrecy and safety needed for the research and development required to design a nuclear fission bomb. Experiments carried out in the 1940s generated both radioactive and hazardous waste constituents on what is presently part of the Los Alamos townsite. Under the RCRA permit issued to Los alamos national Laboratory in 1990, the Laboratory is scheduled for investigation of its solid waste management units (SWMUs). The existing information on levels of radioactivity on the townsite is principally data from soil samples taken during the last site decontamination in 1976, little information on the presence of hazardous constituents exists today. This paper addresses pathway analysis and a preliminary risk assessment for current residents of the Los Alamos townsite. The estimated dose levels, in mrem per year, show that the previously decontaminated SWMU areas on the Los Alamos townsite will not contribute a radiation dose of any concern to the current residents.

  20. Los Alamos contribution to target diagnostics on the National Ignition Facility

    SciTech Connect

    Mack, J.M.; Baker, D.A.; Caldwell, S.E.

    1994-07-01

    The National Ignition Facility (NIF) will have a large suite of sophisticated target diagnostics. This will allow thoroughly diagnosed experiments to be performed both at the ignition and pre-ignition levels. As part of the national effort Los Alamos National Laboratory will design, construct and implement a number of diagnostics for the NIF. This paper describes Los Alamos contributions to the ``phase I diagnostics.`` Phase I represents the most fundamental and basic measurement systems that will form the core for most work on the NIF. The Los Alamos effort falls into four categories: moderate to hard X-ray (time resolved imaging neutron spectroscopy- primarily with neutron time of flight devices; burn diagnostics utilizing gamma ray measurements; testing measurement concepts on the TRIDENT laser system at Los Alamos. Because of the high blast, debris and radiation environment, the design of high resolution X-ray imaging systems present significant challenges. Systems with close target proximity require special protection and methods for such protection is described. The system design specifications based on expected target performance parameters is also described. Diagnosis of nuclear yield and burn will be crucial to the NIF operation. Nuclear reaction diagnosis utilizing both neutron and gamma ray detection is discussed. The Los Alamos TRIDENT laser system will be used extensively for the development of new measurement concepts and diagnostic instrumentation. Some its potential roles in the development of diagnostics for NIF are given.

  1. Interannual variability of the global net radiation balance and its consequence on global energy transport

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Sohn, B. J.

    1990-01-01

    Global cloudiness and radiation budget data from Nimbus 6 and 7 are used to investigate the role of cloud and surface radiative forcing and elements of the earth's general circulation. Although globally integrated cloud forcing is nearly zero, there are large regional imbalances and well regulated processes in the shortwave and longwave spectrum that control the meridional gradient structure of the net radiation balance and the factors modulating the east-west oriented North Africa-western Pacific energy transport dipole. The analysis demonstrates that clouds play a dual role in both the shortwave and longwave spectra in terms of tropical and midlatitude east-west gradients. The key result is that cloud forcing, although not always the principle regulator of interannual variability of the global climate, serves to reinforce the basic three-cell meridional circulation.

  2. Tests of Transport Theory and Reduced Impurity Influx with Highly Radiative Plasmas in TFTR

    NASA Astrophysics Data System (ADS)

    Hill, K. W.

    1997-11-01

    The electron and ion temperature profiles in beam-heated plasmas were observed to be remarkably invariant when radiative losses were increased significantly through gas puffing of high-Z impurities (argon, krypton, xenon) in the Tokamak Fusion Test Reactor. Without impurity puffing, radiative losses accounted for typically only ~ 25\\char'45 of the input power and the radiation profile was strongly peaked at the plasma edge, where the dominant carbon impurity was not fully stripped. At central electron temperatures, T_eo, of ~ 6 keV, trace concentrations of krypton and xenon (n_z/ne ~ 10-3) generated flat and centrally peaked radiation profiles respectively, and a significant fraction of the input power (45-100\\char'45 ) was lost through radiation. This loss provided a nearly ideal technique for studying local heat transport in tokamaks because it perturbed the net heating profile strongly and in a measureable way, with little effect on the density and the beam deposition profiles. In supershot plasmas, Ti >> T_e, the ion temperature profile remained constant, or even increased modestly, as the radiated power fraction was increased to 75-90\\char'45 with krypton and xenon. This observation is surprising because ion-electron coupling is the dominant power loss term for the ions in the core of supershot plasmas, and the central Ti would have decreased a factor of two if the local ion thermal diffusivity had remained constant at its value without impurity puffing. In L-mode plasmas where ion-electron power coupling is a smaller term in the power balance, the electron temperature during impurity puffing also changed only ~ 10-15\\char'45 even as the net power flow through the electrons was decreased by a factor of ~ 3. The ``stiffness" of the temperature profiles to net input power is supportive of transport mechanisms which have a marginal-stability character. Preliminary comparisons of the temperature changes with predictions of the IFS/PPPL transport model

  3. Implementation and display of Computer Aided Design (CAD) models in Monte Carlo radiation transport and shielding applications

    SciTech Connect

    Burns, T.J.

    1994-03-01

    An Xwindow application capable of importing geometric information directly from two Computer Aided Design (CAD) based formats for use in radiation transport and shielding analyses is being developed at ORNL. The application permits the user to graphically view the geometric models imported from the two formats for verification and debugging. Previous models, specifically formatted for the radiation transport and shielding codes can also be imported. Required extensions to the existing combinatorial geometry analysis routines are discussed. Examples illustrating the various options and features which will be implemented in the application are presented. The use of the application as a visualization tool for the output of the radiation transport codes is also discussed.

  4. Explicit solutions of the radiative transport equation in the P{sub 3} approximation

    SciTech Connect

    Liemert, André Kienle, Alwin

    2014-11-01

    Purpose: Explicit solutions of the monoenergetic radiative transport equation in the P{sub 3} approximation have been derived which can be evaluated with nearly the same computational effort as needed for solving the standard diffusion equation (DE). In detail, the authors considered the important case of a semi-infinite medium which is illuminated by a collimated beam of light. Methods: A combination of the classic spherical harmonics method and the recently developed method of rotated reference frames is used for solving the P{sub 3} equations in closed form. Results: The derived solutions are illustrated and compared to exact solutions of the radiative transport equation obtained via the Monte Carlo (MC) method as well as with other approximated analytical solutions. It is shown that for the considered cases which are relevant for biomedical optics applications, the P{sub 3} approximation is close to the exact solution of the radiative transport equation. Conclusions: The authors derived exact analytical solutions of the P{sub 3} equations under consideration of boundary conditions for defining a semi-infinite medium. The good agreement to Monte Carlo simulations in the investigated domains, for example, in the steady-state and time domains, as well as the short evaluation time needed suggests that the derived equations can replace the often applied solutions of the diffusion equation for the homogeneous semi-infinite medium.

  5. The role of radiation transport in the thermal response of semitransparent materials to localized laser heating

    SciTech Connect

    Colvin, Jeffrey; Shestakov, Aleksei; Stolken, James; Vignes, Ryan

    2011-03-09

    Lasers are widely used to modify the internal structure of semitransparent materials for a wide variety of applications, including waveguide fabrication and laser glass damage healing. The gray diffusion approximation used in past models to describe radiation cooling is not adequate for these materials, particularly near the heated surface layer. In this paper we describe a computational model based upon solving the radiation transport equation in 1D by the Pn method with ~500 photon energy bands, and by multi-group radiationdiffusion in 2D with fourteen photon energy bands. The model accounts for the temperature-dependent absorption of infrared laser light and subsequent redistribution of the deposited heat by both radiation and conductive transport. We present representative results for fused silica irradiated with 2–12 W of 4.6 or 10.6 µm laser light for 5–10 s pulse durations in a 1 mm spot, which is small compared to the diameter and thickness of the silica slab. Furthermore, we show that, unlike the case for bulk heating, in localized infrared laser heatingradiation transport plays only a very small role in the thermal response of silica.

  6. Discontinuous Galerkin Methods for the Two-Moment Model of Radiation Transport

    NASA Astrophysics Data System (ADS)

    Endeve, Eirik; Hauck, Cory

    2016-03-01

    We are developing computational methods for simulation of radiation transport in astrophysical systems (e.g., neutrino transport in core-collapse supernovae). Here we consider the two-moment model of radiation transport, where the energy density E and flux F - angular moments of a phase space distribution function - approximates the radiation field in a computationally tractable manner. We aim to develop multi-dimensional methods that are (i) high-order accurate for computational efficiency, and (ii) robust in the sense that the solution remains in the realizable set R = { (E , F) | E >= 0 and E - | F | >= 0 } (i.e., E and F are consistent with moments of an underlying distribution). Our approach is based on the Runge-Kutta discontinuous Galerkin method, which has many attractive properties, including high-order accuracy on a compact stencil. We present the physical model and numerical method, and show results from a multi-dimensional implementation. Tests show that the method is high-order accurate and strictly preserves realizability of the moments.

  7. Equilibrium structure of solar magnetic flux tubes: Energy transport with multistream radiative transfer

    NASA Technical Reports Server (NTRS)

    Hasan, S. S.; Kalkofen, W.

    1994-01-01

    We examine the equilibrium structure of vertical intense magnetic flux tubes on the Sun. Assuming cylindrical geometry, we solve the magnetohydrostatic equations in the thin flux-tube approximation, allowing for energy transport by radiation and convection. The radiative transfer equation is solved in the six-stream approximation, assuming gray opacity and local thermodynamic equilibrium. This constitutes a significant improvement over a previous study, in which the transfer was solved using the multidimensional generalization of the Eddington approximation. Convection in the flux tube is treated using mixing-length theory, with an additional parameter alpha, characterizing the suppression of convective energy transport in the tube by the strong magnetic field. The equations are solved using the method of partial linearization. We present results for tubes with different values of the magnetic field strength and radius at a fixed depth in the atmosphere. In general, we find that, at equal geometric heights, the temperature on the tube axis, compared to the ambient medium, is higher in the photosphere and lower in the convection zone, with the difference becoming larger for thicker tubes. At equal optical depths the tubes are generally hotter than their surroundings. The results are comparatively insensitive to alpha but depend upon whether radiative and convective energy transport operate simultaneously or in separate layers. A comparison of our results with semiempirical models shows that the temperature and intensity contrast are in broad agreement. However, the field strengths of the flux-tube models are somewhat lower than the values inferred from observations.

  8. Radiation Transport Properties of Potential In Situ-Developed Regolith-Epoxy Materials for Martian Habitats

    NASA Technical Reports Server (NTRS)

    Miller, J.; Heilbronn, L.; Singleterry, R. C., Jr.; Thibeault, S. A.; Wilson, J. W.; Zeitlin, C. J.

    2001-01-01

    We will evaluate the radiation transport properties of epoxy-martian regolith composites. Such composites, which would use both in situ materials and chemicals fabricated from elements found in the martian atmosphere, are candidates for use in habitats on Mars. The principal objective is to evaluate the transmission properties of these materials with respect to the protons and heavy charged particles in the galactic cosmic rays which bombard the martian surface. The secondary objective is to evaluate fabrication methods which could lead to technologies for in situ fabrication. The composites will be prepared by NASA Langley Research Center using simulated martian regolith. Initial evaluation of the radiation shielding properties will be made using transport models developed at NASA-LaRC and the results of these calculations will be used to select the composites with the most favorable radiation transmission properties. These candidates will then be empirically evaluated at particle accelerators which produce beams of protons and heavy charged particles comparable in energy to the radiation at the surface of Mars.

  9. Comparisons of several transport models in their predictions in typical space radiation environments

    NASA Astrophysics Data System (ADS)

    Lin, Z. W.; Adams, J. H.; Barghouty, A. F.; Randeniya, S. D.; Tripathi, R. K.; Watts, J. W.; Yepes, P. P.

    2012-02-01

    We have used several transport codes to calculate dose and dose equivalent values as well as the particle spectra behind a slab or inside a spherical shell shielding in typical space radiation environments. Two deterministic codes, HZETRN and UPROP, and two Monte Carlo codes, FLUKA and Geant4, are included. A soft solar particle event, a hard solar particle event, and a solar minimum galactic cosmic rays environment are considered; and the shielding material is either aluminum or polyethylene. We find that the dose values and particle spectra from HZETRN are in general rather consistent with Geant4 except for neutrons. The dose equivalent values from HZETRN and Geant4 are not far from each other, but the HZETRN values behind shielding are often lower than the Geant4 values. Results from FLUKA and Geant4 are mostly consistent for considered cases. However, results from the legacy code UPROP are often quite different from the other transport codes, partly due to its non-consideration of neutrons. Comparisons for the spherical shell geometry exhibit the same qualitative features as for the slab geometry. In addition, results from both deterministic and Monte Carlo transport codes show that the dose equivalent inside the spherical shell decreases from the center to the inner surface and this decrease is large for solar particle events; consistent with an earlier study based on deterministic radiation transport results. This study demonstrates both the consistency and inconsistency among these transport models in their typical space radiation predictions; further studies will be required to pinpoint the exact physics modules in these models that cause the differences and thus may be improved.

  10. Radiation Transport for Explosive Outflows: A Multigroup Hybrid Monte Carlo Method

    NASA Astrophysics Data System (ADS)

    Wollaeger, Ryan T.; van Rossum, Daniel R.; Graziani, Carlo; Couch, Sean M.; Jordan, George C., IV; Lamb, Donald Q.; Moses, Gregory A.

    2013-12-01

    We explore Implicit Monte Carlo (IMC) and discrete diffusion Monte Carlo (DDMC) for radiation transport in high-velocity outflows with structured opacity. The IMC method is a stochastic computational technique for nonlinear radiation transport. IMC is partially implicit in time and may suffer in efficiency when tracking MC particles through optically thick materials. DDMC accelerates IMC in diffusive domains. Abdikamalov extended IMC and DDMC to multigroup, velocity-dependent transport with the intent of modeling neutrino dynamics in core-collapse supernovae. Densmore has also formulated a multifrequency extension to the originally gray DDMC method. We rigorously formulate IMC and DDMC over a high-velocity Lagrangian grid for possible application to photon transport in the post-explosion phase of Type Ia supernovae. This formulation includes an analysis that yields an additional factor in the standard IMC-to-DDMC spatial interface condition. To our knowledge the new boundary condition is distinct from others presented in prior DDMC literature. The method is suitable for a variety of opacity distributions and may be applied to semi-relativistic radiation transport in simple fluids and geometries. Additionally, we test the code, called SuperNu, using an analytic solution having static material, as well as with a manufactured solution for moving material with structured opacities. Finally, we demonstrate with a simple source and 10 group logarithmic wavelength grid that IMC-DDMC performs better than pure IMC in terms of accuracy and speed when there are large disparities between the magnitudes of opacities in adjacent groups. We also present and test our implementation of the new boundary condition.

  11. F--Ray: A new algorithm for efficient transport of ionizing radiation

    NASA Astrophysics Data System (ADS)

    Mao, Yi; Zhang, J.; Wandelt, B. D.; Shapiro, P. R.; Iliev, I. T.

    2014-04-01

    We present a new algorithm for the 3D transport of ionizing radiation, called F2-Ray (Fast Fourier Ray-tracing method). The transfer of ionizing radiation with long mean free path in diffuse intergalactic gas poses a special challenge to standard numerical methods which transport the radiation in position space. Standard methods usually trace each individual ray until it is fully absorbed by the intervening gas. If the mean free path is long, the computational cost and memory load are likely to be prohibitive. We have developed an algorithm that overcomes these limitations and is, therefore, significantly more efficient. The method calculates the transfer of radiation collectively, using the Fast Fourier Transform to convert radiation between position and Fourier spaces, so the computational cost will not increase with the number of ionizing sources. The method also automatically combines parallel rays with the same frequency at the same grid cell, thereby minimizing the memory requirement. The method is explicitly photon-conserving, i.e. the depletion of ionizing photons is guaranteed to equal the photoionizations they caused, and explicitly obeys the periodic boundary condition, i.e. the escape of ionizing photons from one side of a simulation volume is guaranteed to be compensated by emitting the same amount of photons into the volume through the opposite side. Together, these features make it possible to numerically simulate the transfer of ionizing photons more efficiently than previous methods. Since ionizing radiation such as the X-ray is responsible for heating the intergalactic gas when first stars and quasars form at high redshifts, our method can be applied to simulate thermal distribution, in addition to cosmic reionization, in three-dimensional inhomogeneous cosmological density field.

  12. Publications of Los Alamos research 1980

    SciTech Connect

    Salazar, C.A.; Willis, J.K.

    1981-09-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1980. Papers published in 1980 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted-even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was pubished more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-laboratory reports, journal articles, books, chapters of books, conference papers published either separately or as part of conference proceedings issued as books or reports, papers published in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  13. Publications of Los Alamos Research, 1983

    SciTech Connect

    Sheridan, C.J.; McClary, W.J.; Rich, J.A.; Rodriguez, L.L.

    1984-10-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1983. Papers published in 1982 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted - even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was published more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-Laboratory reports, journal articles, books, chapters of books, conference papers either published separately or as part of conference proceedings issued as books or reports, papers publishd in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  14. Water supply at Los Alamos during 1992

    SciTech Connect

    Purtymun, W.D.; McLin, S.G.; Stoker, A.K.; Maes, M.N.

    1995-09-01

    Municipal potable water supply during 1992 was 1,516 {times} 10{sup 6} gallons from wells in the Guaje and Pajarito well fields. About 13 {times} 10{sup 6} gallons were pumped from the Los Alamos Well Field and used in the construction of State Road 501 adjacent to the Field. The last year the Las Alamos Field was used for municipal supply was 1991. The nonpotable water supply used for steam plant support was about 0.12 {times} 10{sup 6} gallons from the spring gallery in Water Canyon. No nonpotable water was used for irrigation from Guaje and Los Alamos Reservoirs. Thus, the total water usage in 1992 was about 1,529 {times} 10{sup 6} gallons. Neither of the two new wells in the Otowi Well Field were operational in 1992.

  15. Grey transport acceleration method for time-dependent radiative transfer problems

    SciTech Connect

    Larsen, E.

    1988-10-01

    A new iterative method for solving hte time-dependent multifrequency radiative transfer equations is described. The method is applicable to semi-implicit time discretizations that generate a linear steady-state multifrequency transport problem with pseudo-scattering within each time step. The standard ''lambda'' iteration method is shown to often converge slowly for such problems, and the new grey transport acceleration (GTA) method, based on accelerating the lambda method by employing a grey, or frequency-independent transport equation, is developed. The GTA method is shown, theoretically by an iterative Fourier analysis, and experimentally by numerical calculations, to converge significantly faster than the lambda method. In addition, the GTA method is conceptually simple to implement for general differencing schemes, on either Eulerian or Lagrangian meshes. copyright 1988 Academic Press, Inc.

  16. Integrated Radiation Transport and Nuclear Fuel Performance for Assembly-Level Simulations

    SciTech Connect

    Clarno, Kevin T; Hamilton, Steven P; Philip, Bobby; Berrill, Mark A; Sampath, Rahul S; Allu, Srikanth; Pugmire, Dave; Dilts, Gary; Banfield, James E

    2012-02-01

    The Advanced Multi-Physics (AMP) Nuclear Fuel Performance code (AMPFuel) is focused on predicting the temperature and strain within a nuclear fuel assembly to evaluate the performance and safety of existing and advanced nuclear fuel bundles within existing and advanced nuclear reactors. AMPFuel was extended to include an integrated nuclear fuel assembly capability for (one-way) coupled radiation transport and nuclear fuel assembly thermo-mechanics. This capability is the initial step toward incorporating an improved predictive nuclear fuel assembly modeling capability to accurately account for source-terms and boundary conditions of traditional (single-pin) nuclear fuel performance simulation, such as the neutron flux distribution, coolant conditions, and assembly mechanical stresses. A novel scheme is introduced for transferring the power distribution from the Scale/Denovo (Denovo) radiation transport code (structured, Cartesian mesh with smeared materials within each cell) to AMPFuel (unstructured, hexagonal mesh with a single material within each cell), allowing the use of a relatively coarse spatial mesh (10 million elements) for the radiation transport and a fine spatial mesh (3.3 billion elements) for thermo-mechanics with very little loss of accuracy. In addition, a new nuclear fuel-specific preconditioner was developed to account for the high aspect ratio of each fuel pin (12 feet axially, but 1 4 inches in diameter) with many individual fuel regions (pellets). With this novel capability, AMPFuel was used to model an entire 17 17 pressurized water reactor fuel assembly with many of the features resolved in three dimensions (for thermo-mechanics and/or neutronics), including the fuel, gap, and cladding of each of the 264 fuel pins; the 25 guide tubes; the top and bottom structural regions; and the upper and lower (neutron) reflector regions. The final, full assembly calculation was executed on Jaguar using 40,000 cores in under 10 hours to model over 162

  17. Integrated Radiation Transport and Nuclear Fuel Performance for Assembly-Level Simulations

    SciTech Connect

    Hamilton, Steven P; Clarno, Kevin T; Philip, Bobby; Berrill, Mark A; Sampath, Rahul S; Allu, Srikanth

    2012-01-01

    The Advanced Multi-Physics (AMP) Nuclear Fuel Performance code (AMPFuel) is focused on predicting the temperature and strain within a nuclear fuel assembly to evaluate the performance and safety of existing and advanced nuclear fuel bundles within existing and advanced nuclear reactors. AMPFuel was extended to include an integrated nuclear fuel assembly capability for (one-way) coupled radiation transport and nuclear fuel assembly thermo-mechanics. This capability is the initial step toward incorporating an improved predictive nuclear fuel assembly modeling capability to accurately account for source-terms, such as neutron flux distribution, coolant conditions and assembly mechanical stresses, of traditional (single-pin) nuclear fuel performance simulation. A novel scheme is introduced for transferring the power distribution from the Scale/Denovo (Denovo) radiation transport code (structured, Cartesian mesh with smeared materials within each cell) to AMPFuel (unstructured, hexagonal mesh with a single material within each cell), allowing the use of a relatively coarse spatial mesh (10 million elements) for the radiation transport and a fine spatial mesh (3.3 billion elements) for thermo-mechanics with very little loss of accuracy. With this novel capability, AMPFuel was used to model an entire 1717 pressurized water reactor fuel assembly with many of the features resolved in three dimensions (for thermo-mechanics and/or neutronics). A full assembly calculation was executed on Jaguar using 40,000 cores in under 10 hours to model over 160 billion degrees of freedom for 10 loading steps. The single radiation transport calculation required about 50% of the time required to solve the thermo-mechanics with a single loading step, which demonstrates that it is feasible to incorporate, in a single code, a high-fidelity radiation transport capability with a high-fidelity nuclear fuel thermo-mechanics capability and anticipate acceptable computational requirements. The

  18. Desert dust transported over Europe: Lidar observations and model evaluation of the radiative impact

    NASA Astrophysics Data System (ADS)

    Pitari, Giovanni; Di Genova, Glauco; Coppari, Eleonora; De Luca, Natalia; Di Carlo, Piero; Iarlori, Marco; Rizi, Vincenzo

    2015-04-01

    Three years of measurements of aerosol vertical profiles (2007-2009) made at the lidar station of L'Aquila, a site in central Italy that is part of the European Aerosol Research Lidar Network, are studied by means of well-tested radiative transfer models to analyze the radiative impact of mineral dust aerosols transported from the Sahara desert. Sixteen major episodes of desert dust transport are considered; the radiative analysis is conducted in terms of diurnal averages of the top-of-atmosphere radiative flux changes (TOARFC) with respect to a reference "clean" aerosol profile not perturbed by long-range transported desert particles. The aerosol size distribution, needed as an input parameter for the Mie scattering program to obtain single-scattering albedo, asymmetry parameter, and extinction scaling over the whole wavelength spectrum, is obtained from simultaneous surface measurements with a multichannel aerosol spectrometer. The calculated average net TOARFC is +2.3 and +3.0 W/m2 in clear- and total-sky conditions, respectively. Solar, planetary components account for -0.42 and +2.7 W/m2 in clear-sky conditions and +0.93 and +2.1 W/m2 in total-sky conditions, respectively. The large effective radius of these coarse mode soil dust particles (reff = 1.5 µm) makes the longwave planetary component of the TOARFC dominant over the solar component, at least for typical continental surface albedo values (0.18 on average, at L'Aquila). The solar component, however, shows a pronounced sensitivity to the surface albedo and becomes dominant over the longwave component for both an ocean albedo (0.07) and a typical surface-snow albedo (0.4), with TOARFC values of -6.3 and +10.6 W/m2, respectively.

  19. Simulating photon-transport in uniform media using the radiative transport equation: a study using the Neumann-series approach

    PubMed Central

    Jha, Abhinav K.; Kupinski, Matthew A.; Masumura, Takahiro; Clarkson, Eric; Maslov, Alexey V.; Barrett, Harrison H.

    2014-01-01

    We present the implementation, validation, and performance of a Neumann-series approach for simulating light propagation at optical wavelengths in uniform media using the radiative transport equation (RTE). The RTE is solved for an anisotropic-scattering medium in a spherical harmonic basis for a diffuse-optical-imaging setup. The main objectives of this paper are threefold: to present the theory behind the Neumann-series form for the RTE, to design and develop the mathematical methods and the software to implement the Neumann series for a diffuse-optical-imaging setup, and, finally, to perform an exhaustive study of the accuracy, practical limitations, and computational efficiency of the Neumann-series method. Through our results, we demonstrate that the Neumann-series approach can be used to model light propagation in uniform media with small geometries at optical wavelengths. PMID:23201893

  20. The Los Alamos suite of relativistic atomic physics codes

    DOE PAGES

    Fontes, C. J.; Zhang, H. L.; Jr, J. Abdallah; ...

    2015-05-28

    The Los Alamos SuitE of Relativistic (LASER) atomic physics codes is a robust, mature platform that has been used to model highly charged ions in a variety of ways. The suite includes capabilities for calculating data related to fundamental atomic structure, as well as the processes of photoexcitation, electron-impact excitation and ionization, photoionization and autoionization within a consistent framework. These data can be of a basic nature, such as cross sections and collision strengths, which are useful in making predictions that can be compared with experiments to test fundamental theories of highly charged ions, such as quantum electrodynamics. The suitemore » can also be used to generate detailed models of energy levels and rate coefficients, and to apply them in the collisional-radiative modeling of plasmas over a wide range of conditions. Such modeling is useful, for example, in the interpretation of spectra generated by a variety of plasmas. In this work, we provide a brief overview of the capabilities within the Los Alamos relativistic suite along with some examples of its application to the modeling of highly charged ions.« less

  1. The Los Alamos suite of relativistic atomic physics codes

    SciTech Connect

    Fontes, C. J.; Zhang, H. L.; Jr, J. Abdallah; Clark, R. E. H.; Kilcrease, D. P.; Colgan, J.; Cunningham, R. T.; Hakel, P.; Magee, N. H.; Sherrill, M. E.

    2015-05-28

    The Los Alamos SuitE of Relativistic (LASER) atomic physics codes is a robust, mature platform that has been used to model highly charged ions in a variety of ways. The suite includes capabilities for calculating data related to fundamental atomic structure, as well as the processes of photoexcitation, electron-impact excitation and ionization, photoionization and autoionization within a consistent framework. These data can be of a basic nature, such as cross sections and collision strengths, which are useful in making predictions that can be compared with experiments to test fundamental theories of highly charged ions, such as quantum electrodynamics. The suite can also be used to generate detailed models of energy levels and rate coefficients, and to apply them in the collisional-radiative modeling of plasmas over a wide range of conditions. Such modeling is useful, for example, in the interpretation of spectra generated by a variety of plasmas. In this work, we provide a brief overview of the capabilities within the Los Alamos relativistic suite along with some examples of its application to the modeling of highly charged ions.

  2. Advances in nuclear data and all-particle transport for radiation oncology

    SciTech Connect

    White, R.M.; Chadwick, M.B.; Chandler, W.P.; Hartmann Siantar, C.L.; Westbrook, C.K.

    1994-05-01

    Fast neutrons have been used to treat over 15,000 cancer patients worldwide and proton therapy is rapidly emerging as a treatment of choice for tumors around critical anatomical structures. Neutron therapy requires evaluated data to {approximately}70 MeV while proton therapy requires data to {approximately}250 MeV. Collaboration between Lawrence Livermore National Laboratory (LLNL) and the medical physics community has revealed limitations in nuclear cross section evaluations and radiation transport capabilities that have prevented neutron and proton radiation therapy centers from using Monte Carlo calculations to accurately predict dose in patients. These evaluations require energy- and angle-dependent cross sections for secondary neutrons, charged-particles and recoil nuclei. We are expanding the LLNL nuclear databases to higher energies for biologically important elements and have developed a three-dimensional, all-particle Monte Carlo radiation transport code that uses computer-assisted-tomography (CT) images as the input mesh. This code, called PEREGRINE calculates dose distributions in the human body and can be used as a tool to determine the dependence of dose on details of the evaluated nuclear data. In this paper, we will review the status of the nuclear data required for neutron and proton therapy, describe the capabilities of the PEREGRINE package, and show the effects of tissue inhomogeneities on dose distribution.

  3. Overview and applications of the Monte Carlo radiation transport kit at LLNL

    SciTech Connect

    Sale, K E

    1999-06-23

    Modern Monte Carlo radiation transport codes can be applied to model most applications of radiation, from optical to TeV photons, from thermal neutrons to heavy ions. Simulations can include any desired level of detail in three-dimensional geometries using the right level of detail in the reaction physics. The technology areas to which we have applied these codes include medical applications, defense, safety and security programs, nuclear safeguards and industrial and research system design and control. The main reason such applications are interesting is that by using these tools substantial savings of time and effort (i.e. money) can be realized. In addition it is possible to separate out and investigate computationally effects which can not be isolated and studied in experiments. In model calculations, just as in real life, one must take care in order to get the correct answer to the right question. Advancing computing technology allows extensions of Monte Carlo applications in two directions. First, as computers become more powerful more problems can be accurately modeled. Second, as computing power becomes cheaper Monte Carlo methods become accessible more widely. An overview of the set of Monte Carlo radiation transport tools in use a LLNL will be presented along with a few examples of applications and future directions.

  4. The Role of ULF Driven Radial Transport in Rebuilding the Earth's Outer Radiation Belts

    NASA Astrophysics Data System (ADS)

    Kress, B. T.; Hudson, M. K.; Paral, J.; Selesnick, R.; Claudepierre, S. G.

    2015-12-01

    An outstanding question addressed by recent studies of the Earth's radiation belts is, what are the physical processes responsible rapid recovery of MeV electrons in the outer belt during geomagnetic storms? Rapid rebuilding of the ~1 MeV electron population near geosynchronous during periods of strongly southward IMF BZ is well modeled by computing test-particle trajectories in MHD magnetospheric model fields. The build up of ~2 MeV electrons at lower L, observed by the Van Allen Probes, is also reproduced in the test-particle model. It is not known however to what extent adiabatic transport is sufficient to produce the observed multi-MeV flux enhancements in the outer belt. By comparing observations with model results, we can determine the inward extent and high energy limit of radiation belt rebuilding due to ULF driven radial transport alone. Results from case studies of several recent geomagnetic storms occurring in conjunction with recovery of the outer radiation belts will be presented.

  5. Induction inserts at the Los Alamos PSR

    SciTech Connect

    King-Yuen Ng

    2002-09-30

    Ferrite-loaded induction tuners installed in the Los Alamos Proton Storage Ring have been successful in compensating space-charge effects. However, the resistive part of the ferrite introduces unacceptable microwave instability and severe bunch lengthening. An effective cure was found by heating the ferrite cores up to {approx} 130 C. An understanding of the instability and cure is presented.

  6. A Sailor in the Los Alamos Navy

    SciTech Connect

    Judd, D. L.

    2016-12-20

    As part of the War Department’s Manhattan Engineer District (MED), Los Alamos was an Army installation during World War II, complete with a base commander and a brace of MPs. But it was a unique Army installation, having more civilian then military personnel. Even more unique was the work performed by the civilian population, work that required highly educated scientists and engineers. As the breadth, scope, and complexity of the Laboratory’s work increased, more and more technically educated and trained personnel were needed. But, the manpower needs of the nation’s war economy had created a shortage of such people. To meet its manpower needs, the MED scoured the ranks of the Army for anyone who had technical training and reassigned these men to its laboratories, including Los Alamos, as part of its Special Engineer Detachment (SED). Among the SEDs assigned to Los Alamos was Val Fitch, who was awarded the Nobel Prize in Physics in 1980. Another was Al Van Vessem, who helped stack the TNT for the 100 ton test, bolted together the Trinity device, and rode shotgun with the bomb has it was driven from Los Alamos to ground zero.

  7. Current Status of Radiation Transport Tools for Proliferation and Terrorism Prevention

    SciTech Connect

    Sale, K E

    2004-09-13

    We present the current status and future plans for the set of calculational tools and data bases developed and maintained at LLNL. The calculational tools include the Monte Carlo codes TART and COG as well as the deterministic code ARDRA. In addition to these codes presently in use there is a major development effort for a new massively parallel transport code. An important part of the capability we're developing is a sophisticated user interface, based on a commercial 3-D modeling product, to improve the model development process. A major part of this user interface tool is being developed by Strela under the Nuclear Cities Initiative. Strela has developed a hub-and-spoke technology for code input interconversions (between COG, TART and MCNP) and will produce the plug-ins that extend the capabilities of the 3-D modeler for use as a radiation transport input generator. The major advantages of this approach are the built-in user interface for 3-D modeling and the ability to read a large variety of CAD-file formats. In addition to supporting our current radiation transport codes and developing new capabilities we are working on some nuclear data needs for homeland security. These projects are carried out and the Lawrence Berkeley National Laboratory 88'' cyclotron and at the Institute for Nuclear Research of the National Academy of Science of Ukraine under an STCU contract.

  8. Comparisons of Integrated Radiation Transport Models with Microdosimetry Data in Spaceflight

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Nikjoo, H.; Kim, M. Y.; Hu, X.; Dicello, J. F.; Pisacane, V. L.

    2006-01-01

    Astronauts are exposed to galactic cosmic rays (GCR), trapped protons, and possible solar particle events (SPE) during spaceflight. For such complicated mixtures of radiation types and kinetic energies, tissue equivalent proportional counters (TEPC's) represent a simple time-dependent approach for radiation monitoring. Of interest in radiation protection is the average quality factor of a radiation field defined as a function of linear energy transfer, LET, Q(sub ave)(LET). However TEPC's measure the average quality factors as a function of lineal energy (y), Q(sub ave)(y) defined as the average energy deposition in a volume divided by the average chord length of the volume. Lineal energy, y deviates from LET due to energy straggling, delta-ray escape or entry, and nuclear fragments produced in the detector. Using integrated space radiation models that includes the transport code HZETRN/BRYNTRN, the quantum nuclear interaction model, QMSFRG, and results from Monte-Carlo track simulations of TEPC's response to ions, we consider comparisons of model calculations to TEPC results from NASA missions in low Earth orbit and make predictions for lunar and Mars missions. Good agreement between the model and measured spectra from past NASA missions is found. A finding of this work is that TEPC's values for trapped or solar protons of Q(sub ave)(y) range from 1.9-2.5, overestimating Q(sub ave)(LET), which ranges from 1.4-1.6 with both quantities increasing with shielding depth due to nuclear secondaries Comparisons for the complete GCR spectra show that Q(sub ave)(LET) for GCR is approximately 3.5-4.5, while TEPC's measure 2.9-3.4 for Q(sub ave)(y) with the GCR values decreasing with depth as heavy ions are absorbed in shielding material. Our results support the use of TEPC's for space radiation environmental monitoring when computational analysis is used for proper data interpretation.

  9. NASA astronaut dosimetry: Implementation of scalable human phantoms and benchmark comparisons of deterministic versus Monte Carlo radiation transport

    NASA Astrophysics Data System (ADS)

    Bahadori, Amir Alexander

    Astronauts are exposed to a unique radiation environment in space. United States terrestrial radiation worker limits, derived from guidelines produced by scientific panels, do not apply to astronauts. Limits for astronauts have changed throughout the Space Age, eventually reaching the current National Aeronautics and Space Administration limit of 3% risk of exposure induced death, with an administrative stipulation that the risk be assured to the upper 95% confidence limit. Much effort has been spent on reducing the uncertainty associated with evaluating astronaut risk for radiogenic cancer mortality, while tools that affect the accuracy of the calculations have largely remained unchanged. In the present study, the impacts of using more realistic computational phantoms with size variability to represent astronauts with simplified deterministic radiation transport were evaluated. Next, the impacts of microgravity-induced body changes on space radiation dosimetry using the same transport method were investigated. Finally, dosimetry and risk calculations resulting from Monte Carlo radiation transport were compared with results obtained using simplified deterministic radiation transport. The results of the present study indicated that the use of phantoms that more accurately represent human anatomy can substantially improve space radiation dose estimates, most notably for exposures from solar particle events under light shielding conditions. Microgravity-induced changes were less important, but results showed that flexible phantoms could assist in optimizing astronaut body position for reducing exposures during solar particle events. Finally, little overall differences in risk calculations using simplified deterministic radiation transport and 3D Monte Carlo radiation transport were found; however, for the galactic cosmic ray ion spectra, compensating errors were observed for the constituent ions, thus exhibiting the need to perform evaluations on a particle

  10. Influence of radiative recombination on the minority-carrier transport in direct band-gap semiconductors

    NASA Technical Reports Server (NTRS)

    Von Roos, O.

    1983-01-01

    When a semiconductor sample is irradiated by means of an external source, emitting photons or electrons, excess carriers are produced which distribute themselves throughout the sample. One of the parameters which determine the distribution of the carriers is the surface recombination velocity. The present investigation is concerned with the recombination lifetime tau. The predominant mechanism for recombination in wide band-gap semiconductors is described by the Shockley-Read-Hall (SRH) theory. The transport equations are derived for free carriers and the radiation field. The considered theory is applied to a semiinfinite, one-dimensional semiconductor slab irradiated by light of a given frequency. Some numerical considerations based on n-type GaAs are presented. Attention is given to a determination of the radiation transmitted through the surface of the sample.

  11. Terahertz radiation induced chaotic electron transport in semiconductor superlattices with a tilted magnetic field

    SciTech Connect

    Wang, C. Wang, F.; Cao, J. C.

    2014-09-01

    Chaotic electron transport in semiconductor superlattice induced by terahertz electric field that is superimposed on a dc electric field along the superlattice axis are studied using the semiclassical motion equations including the effect of dissipation. A magnetic field that is tilted relative to the superlattice axis is also applied to the system. Numerical simulation shows that electrons in superlattice miniband exhibit complicate nonlinear oscillating modes with the influence of terahertz radiation. Transitions between frequency-locking and chaos via pattern forming bifurcations are observed with the varying of terahertz amplitude. It is found that the chaotic regions gradually contract as the dissipation increases. We attribute the appearance of complicate nonlinear oscillation in superlattice to the interaction between terahertz radiation and internal cooperative oscillating mode relative to Bloch oscillation and cyclotron oscillation.

  12. Radiative transport in the delta-P1 approximation for semi-infinite turbid media

    PubMed Central

    Seo, InSeok; Hayakawa, Carole K.; Venugopalan, Vasan

    2012-01-01

    We have developed an analytic solution for spatially resolved diffuse reflectance within the δ-P1 approximation to the radiative transport equation for a semi-infinite homogeneous turbid medium. We evaluate the performance of this solution by comparing its predictions with those provided by Monte Carlo simulations and the standard diffusion approximation. We demonstrate that the δ-P1 approximation provides accurate estimates for spatially resolved diffuse reflectance in both low and high scattering media. We also develop a multi-stage nonlinear optimization algorithm in which the radiative transport estimates provided by the δ-P1 approximation are used to recover the optical absorption (μa), reduced scattering ( μs′), and single-scattering asymmetry coefficients (g1) of liquid and solid phantoms from experimental measurements of spatially resolved diffuse reflectance. Specifically, the δ-P1 approximation can be used to recover μa, μs′, and g1 with errors within ±22%, ±18%, and ±17%, respectively, for both intralipid-based and siloxane-based tissue phantoms. These phantoms span the optical property range 4<(μs′/μa)<117. Using these same measurements, application of the standard diffusion approximation resulted in the recovery of μa and μs′ with errors of ±29% and ±25%, respectively. Collectively, these results demonstrate that the δ-P1 approximation provides accurate radiative transport estimates that can be used to determine accurately the optical properties of biological tissues, particularly in spectral regions where tissue may display moderate/low ratios of reduced scattering to absorption ( μs′/μa). PMID:18383690

  13. Modeling Interactions Among Turbulence, Gas-Phase Chemistry, Soot and Radiation Using Transported PDF Methods

    NASA Astrophysics Data System (ADS)

    Haworth, Daniel

    2013-11-01

    The importance of explicitly accounting for the effects of unresolved turbulent fluctuations in Reynolds-averaged and large-eddy simulations of chemically reacting turbulent flows is increasingly recognized. Transported probability density function (PDF) methods have emerged as one of the most promising modeling approaches for this purpose. In particular, PDF methods provide an elegant and effective resolution to the closure problems that arise from averaging or filtering terms that correspond to nonlinear point processes, including chemical reaction source terms and radiative emission. PDF methods traditionally have been associated with studies of turbulence-chemistry interactions in laboratory-scale, atmospheric-pressure, nonluminous, statistically stationary nonpremixed turbulent flames; and Lagrangian particle-based Monte Carlo numerical algorithms have been the predominant method for solving modeled PDF transport equations. Recent advances and trends in PDF methods are reviewed and discussed. These include advances in particle-based algorithms, alternatives to particle-based algorithms (e.g., Eulerian field methods), treatment of combustion regimes beyond low-to-moderate-Damköhler-number nonpremixed systems (e.g., premixed flamelets), extensions to include radiation heat transfer and multiphase systems (e.g., soot and fuel sprays), and the use of PDF methods as the basis for subfilter-scale modeling in large-eddy simulation. Examples are provided that illustrate the utility and effectiveness of PDF methods for physics discovery and for applications to practical combustion systems. These include comparisons of results obtained using the PDF method with those from models that neglect unresolved turbulent fluctuations in composition and temperature in the averaged or filtered chemical source terms and/or the radiation heat transfer source terms. In this way, the effects of turbulence-chemistry-radiation interactions can be isolated and quantified.

  14. A Polar Discrete Ordinate Radiation Transport Method for 2D ALE Meshes in HYDRA

    NASA Astrophysics Data System (ADS)

    Chang, Britton; Marinak, Marty; Weber, Chris; Peterson, Luc

    2016-10-01

    The Polar Discrete Ordinate Radiation Transport Method in HYDRA has been extended to handle general 2D r-z meshes. Previously the method was only for orthogonal 2D meshes. The new method can be employed with the ALE methodology for managing mesh motion that is used to simulate Rayleigh-Taylor and Richtmyer-Meshkov instabilities on NIF capsule implosions. The results of an examination of this kind will be compared to those obtained by the corresponding diffusion method. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  15. Iterative method for bioluminescence tomography based on the radiative transport equation

    NASA Astrophysics Data System (ADS)

    Cong, Wenxiang; Wang, Ge

    2006-08-01

    Bioluminescence tomography (BLT) is a new molecular imaging modality, which helps study cancer and other diseases, develop drugs, and so on. This technology localizes and quantifies a bioluminescent source inside a living transgenic mouse, and is very useful in many biomedical applications. In this paper, we propose a novel algorithm based on the radiative transport equation to reconstruct the bioluminescence source distribution from data measured on the external surface of a mouse. Our approach transforms the transport equation into an integral equation of the second kind, and establishes a linear system to link the measured photon fluence rate with the unknown light source variables. A regularization measure is taken to overcome the ill-posedness of the inverse problem. Then, an iterative optimization technique with a simple constrain is employed to compute the desirable solution. The physical phantom experiments have been performed to demonstrate the feasibility of the reconstruction method, and evaluate its performance in terms of source location and power estimation.

  16. Gray and multigroup radiation transport through 3D binary stochastic media with different sphere radii distributions

    NASA Astrophysics Data System (ADS)

    Olson, Gordon L.

    2017-03-01

    Gray and multigroup radiation is transported through 3D media consisting of spheres randomly placed in a uniform background. Comparisons are made between using constant radii spheres and three different distributions of sphere radii. Because of the computational cost of 3D calculations, only the lowest angle order, n=1, is tested. If the mean chord length is held constant, using different radii distributions makes little difference. This is true for both gray and multigroup solutions. 3D transport solutions are compared to 2D and 1D solutions with the same mean chord lengths. 2D disk and 3D sphere media give solutions that are nearly identical while 1D slab solutions are fundamentally different.

  17. Gray and multigroup radiation transport through 3D binary stochastic media with different sphere radii distributions

    DOE PAGES

    Olson, Gordon Lee

    2016-12-06

    Here, gray and multigroup radiation is transported through 3D media consisting of spheres randomly placed in a uniform background. Comparisons are made between using constant radii spheres and three different distributions of sphere radii. Because of the computational cost of 3D calculations, only the lowest angle order, n=1, is tested. If the mean chord length is held constant, using different radii distributions makes little difference. This is true for both gray and multigroup solutions. 3D transport solutions are compared to 2D and 1D solutions with the same mean chord lengths. 2D disk and 3D sphere media give solutions that aremore » nearly identical while 1D slab solutions are fundamentally different.« less

  18. Gray and multigroup radiation transport through 3D binary stochastic media with different sphere radii distributions

    SciTech Connect

    Olson, Gordon Lee

    2016-12-06

    Here, gray and multigroup radiation is transported through 3D media consisting of spheres randomly placed in a uniform background. Comparisons are made between using constant radii spheres and three different distributions of sphere radii. Because of the computational cost of 3D calculations, only the lowest angle order, n=1, is tested. If the mean chord length is held constant, using different radii distributions makes little difference. This is true for both gray and multigroup solutions. 3D transport solutions are compared to 2D and 1D solutions with the same mean chord lengths. 2D disk and 3D sphere media give solutions that are nearly identical while 1D slab solutions are fundamentally different.

  19. Transport of and radiation production by transrelativistic and nonrelativistic particles moving through sub-Larmor-scale electromagnetic turbulence

    NASA Astrophysics Data System (ADS)

    Keenan, Brett D.; Ford, Alexander L.; Medvedev, Mikhail V.

    2015-09-01

    Plasmas with electromagnetic fields turbulent at sub-Larmor scales are a feature of a wide variety of high-energy-density environments and are essential to the description of many astrophysical and laboratory plasma phenomena. Radiation from particles, whether they are relativistic or nonrelativistic, moving through small-scale magnetic turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation. The radiation, carrying information on the statistical properties of the magnetic turbulence, is also intimately related to the particle diffusive transport. We have investigated, both theoretically and numerically, the transport of nonrelativistic and trans-relativistic particles in plasmas with high-amplitude isotropic sub-Larmor-scale magnetic turbulence, and its relation to the spectra of radiation simultaneously produced by these particles. Consequently, the diffusive and radiative properties of plasmas turbulent on sub-Larmor scales may serve as a powerful tool to diagnosis laboratory and astrophysical plasmas.

  20. Studies of Radiation-Driven and Buoyancy-Driven Fluid Flows and Transport

    NASA Technical Reports Server (NTRS)

    Ronney, Paul D.; Fortmeyer, Justin M.

    1996-01-01

    It is well known that radiative heat transport influences many types of buoyant flows due to its effect on the temperature and thus density field in the fluid medium. It is of interest to study gaseous flows driven solely by radiation in the absence of buoyancy, particularly because of its application to astrophysical flows that are well known from astronomical observations and numerical simulation. However, no laboratory-scale experiments of this phenomenon have ever been conducted. To study the possibility of obtaining such flows in the laboratory, an apparatus was built to produce large temperature differences (Delta (T)) up to 300 K in a gas confined between flat parallel plates. SF6 was used as the radiatively-active gas because its Planck absorption length is much shorter than that of any other common non-reactive gas. The NASA-Lewis 2.2 second drop tower was used to obtain reduced gravity in order to suppress buoyancy effects. To image the resulting flows, a laser shearing interferometer was employed. Initial results indicate the presence of flow that does not appear to be attributable to the residual flow resulting from buoyancy influences before the drop. For Delta(T) greater than 70 K, slight deformations in the interferometer fringes seen at lower Delta(T) became large unsteady swirls. Such behavior did not occur for radiatively-inactive gases, suggesting that a flow driven solely by radiation was obtained in SF6 and to a lesser extent in CO2. This was more pronounced at higher pressures and plate spacings, consistent with our scaling predictions.

  1. Line-by-line transport calculations for Jupiter entry probes. [of radiative transfer

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.; Cooper, D. M.; Park, C.; Prakash, S. G.

    1979-01-01

    Line-by-line calculations of the radiative transport for a condition near peak heating for entry of the Galileo probe into the Jovian atmosphere are described. The discussion includes a thorough specification of the atomic and molecular input data used in the calculations that could be useful to others working in the field. The results show that the use of spectrally averaged cross sections for diatomic absorbers such as CO and C2 in the boundary layer can lead to an underestimation (by as much as 29%) of the spectral flux at the stagnation point. On the other hand, for the turbulent region near the cone frustum on the probe, the flow tends to be optically thin, and the spectrally averaged results commonly used in coupled radiative transport-flow field calculations are in good agreement with the present line-by-line results. It is recommended that these results be taken into account in sizing the final thickness of the Galileo's heat shield.

  2. Transport and radiative impacts of atmospheric pollen using online, observation-based emissions

    NASA Astrophysics Data System (ADS)

    Wozniak, M. C.; Steiner, A. L.; Solmon, F.; Li, Y.

    2015-12-01

    Atmospheric pollen emitted from trees and grasses exhibits both a high temporal variability and a highly localized spatial distribution that has been difficult to quantify in the atmosphere. Pollen's radiative impact is also not quantified because it is neglected in climate modeling studies. Here we couple an online, meteorological active pollen emissions model guided by observations of airborne pollen to understand the role of pollen in the atmosphere. We use existing pollen counts from 2003-2008 across the continental U.S. in conjunction with a tree database and historical meteorological data to create an observation-based phenological model that produces accurately scaled and timed emissions. These emissions are emitted and transported within the regional climate model (RegCM4) and the direct radiative effect is calculated. Additionally, we simulate the rupture of coarse pollen grains into finer particles by adding a second size mode for pollen emissions, which contributes to the shortwave radiative forcing and also has an indirect effect on climate.

  3. Effect of localized surface-plasmon mode on exciton transport and radiation emission in carbon nanotubes.

    PubMed

    Roslyak, Oleksiy; Cherqui, Charles; Dunlap, David H; Piryatinski, Andrei

    2014-07-17

    We report on a general theoretical approach to study exciton transport and emission in a single-walled carbon nanotube (SWNT) in the presence of a localized surface-plasmon (SP) mode within a metal nanoparticle interacting via near-field coupling. We derive a set of quantum mechanical equations of motion and approximate rate equations that account for the exciton, SP, and the environmental degrees of freedom. The material equations are complemented by an expression for the radiated power that depends on the exciton and SP populations and coherences, allowing for an examination of the angular distribution of the emitted radiation that would be measured in experiment. Numerical simulations for a (6,5) SWNT and cone-shaped Ag metal tip (MT) have been performed using this methodology. Comparison with physical parameters shows that the near-field interaction between the exciton-SP occurs in a weak coupling regime, with the diffusion processes being much faster than the exciton-SP population exchange. In such a case, the effect of the exciton population transfer to the MT with its subsequent dissipation (i.e., the Förster energy transfer) is to modify the exciton steady state distribution while reducing the equilibration time for excitons to reach a steady sate distribution. We find that the radiation distribution is dominated by SP emission for a SWNT-MT separation of a few tens of nanometers due to the fast SP emission rate, whereas the exciton-SP coherences can cause its rotation.

  4. Comparison of Radiation Transport Codes, HZETRN, HETC and FLUKA, Using the 1956 Webber SPE Spectrum

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Slaba, Tony C.; Blattnig, Steve R.; Tripathi, Ram K.; Townsend, Lawrence W.; Handler, Thomas; Gabriel, Tony A.; Pinsky, Lawrence S.; Reddell, Brandon; Clowdsley, Martha S.; Singleterry, Robert C.; Norbury, John W.; Badavi, Francis F.; Aghara, Sukesh K.

    2009-01-01

    Protection of astronauts and instrumentation from galactic cosmic rays (GCR) and solar particle events (SPE) in the harsh environment of space is of prime importance in the design of personal shielding, spacec raft, and mission planning. Early entry of radiation constraints into the design process enables optimal shielding strategies, but demands efficient and accurate tools that can be used by design engineers in every phase of an evolving space project. The radiation transport code , HZETRN, is an efficient tool for analyzing the shielding effectiveness of materials exposed to space radiation. In this paper, HZETRN is compared to the Monte Carlo codes HETC-HEDS and FLUKA, for a shield/target configuration comprised of a 20 g/sq cm Aluminum slab in front of a 30 g/cm^2 slab of water exposed to the February 1956 SPE, as mode led by the Webber spectrum. Neutron and proton fluence spectra, as well as dose and dose equivalent values, are compared at various depths in the water target. This study shows that there are many regions where HZETRN agrees with both HETC-HEDS and FLUKA for this shield/target configuration and the SPE environment. However, there are also regions where there are appreciable differences between the three computer c odes.

  5. Doppler effects on 3-D non-LTE radiation transport and emission spectra.

    SciTech Connect

    Giuliani, J. L.; Davis, J.; DasGupta, A.; Apruzese, John P.; Jennings, Christopher A.; Clark, R. W.; Ampleford, David J.; Bailey, James E.; Thornhill, Joseph W.; Cuneo, Michael Edward; Rochau, Gregory Alan; Coverdale, Christine Anne; Jones, Brent Manley; Hansen, Stephanie B.

    2010-10-01

    Spatially and temporally resolved X-ray emission lines contain information about temperatures, densities, velocities, and the gradients in a plasma. Extracting this information from optically thick lines emitted from complex ions in dynamic, three-dimensional, non-LTE plasmas requires self-consistent accounting for both non-LTE atomic physics and non-local radiative transfer. We present a brief description of a hybrid-structure spectroscopic atomic model coupled to an iterative tabular on-the-spot treatment of radiative transfer that can be applied to plasmas of arbitrary material composition, conditions, and geometries. The effects of Doppler line shifts on the self-consistent radiative transfer within the plasma and the emergent emission and absorption spectra are included in the model. Sample calculations for a two-level atom in a uniform cylindrical plasma are given, showing reasonable agreement with more sophisticated transport models and illustrating the potential complexity - or richness - of radially resolved emission lines from an imploding cylindrical plasma. Also presented is a comparison of modeled L- and K-shell spectra to temporally and radially resolved emission data from a Cu:Ni plasma. Finally, some shortcomings of the model and possible paths for improvement are discussed.

  6. Carbon dioxide and climate: The effects of water transport in radiative-convective models

    NASA Astrophysics Data System (ADS)

    Hummel, John R.; Reck, Ruth A.

    1981-12-01

    Considerable attention is being focused on the possible climatic effects resulting from increases in the concentration of atmospheric carbon dioxide. In calculating CO2 influence on the thermal structure of the atmosphere, the role of clouds is critically important. Not only are the cloud properties, such as amount, numbers of clouds, altitudes, and optical properties important but also whether or not these properties are fixed or coupled to model temperatures. The transport of water vapor determines whether or not a region has clouds, the cloud properites, and the water vapor profiles appropriate for clear and cloudy skies. Results are presented of the change in surface temperature with changes in carbon dioxide content for two radiative-convective models with three different cloud coverages. We used (1) the Manabe-Wetherald radiative-convective model in which three clouds with fixed pressures, thicknesses, and optical properties and a single water vapor profile are inputed and (2) the Hummel-Kuhn model, which couples radiative heating, convection, and water vapor transport in order to calculate locations and thicknesses. The Hummel-Kuhn model yields temperature increases for doubled CO2 larger than the Manabe-Wetherald model for various assumed total cloud cover amounts. For assumed standard cloud cover amounts the Hummel-Kuhn estimate is 20% larger than the Manabe-Wetherald estimate. For reduced and enhanced cloud cover amounts the Hummel-Kuhn estimates are 37% and 17% larger, respectively. The calculated cloud locations and thicknesses did not change in the calculations; therefore the increased sensitivity in the Hummel-Kuhn model is due to the larger water vapor amounts in the Hummel-Kuhn model and the added infrared absorption by the water vapor dimer.

  7. Recent Infrasound Calibration Activity at Los Alamos

    NASA Astrophysics Data System (ADS)

    Whitaker, R. W.; Marcillo, O. E.

    2014-12-01

    Absolute infrasound sensor calibration is necessary for estimating source sizes from measured waveforms. This can be an important function in treaty monitoring. The Los Alamos infrasound calibration chamber is capable of absolute calibration. Early in 2014 the Los Alamos infrasound calibration chamber resumed operations in its new location after an unplanned move two years earlier. The chamber has two sources of calibration signals. The first is the original mechanical piston, and the second is a CLD Dynamics Model 316 electro-mechanical unit that can be digitally controlled and provide a richer set of calibration options. During 2008-2010 a number of upgrades were incorporated for improved operation and recording. In this poster we give an overview of recent chamber work on sensor calibrations, calibration with the CLD unit, some measurements with different porous hoses and work with impulse sources.

  8. Nuclear Forensics at Los Alamos National Laboratory

    SciTech Connect

    Podlesak, David W; Steiner, Robert E.; Burns, Carol J.; LaMont, Stephen P.; Tandon, Lav

    2012-08-09

    The overview of this presentation is: (1) Introduction to nonproliferation efforts; (2) Scope of activities at Los Alamos National Laboratory; (3) Facilities for radioanalytical work at LANL; (4) Radiochemical characterization capabilities; and (5) Bulk chemical and materials analysis capabilities. Some conclusions are: (1) Analytical chemistry measurements on plutonium and uranium matrices are critical to numerous defense and non-defense programs including safeguards accountancy verification measurements; (2) Los Alamos National Laboratory operates capable actinide analytical chemistry and material science laboratories suitable for nuclear material forensic characterization; (3) Actinide analytical chemistry uses numerous means to validate and independently verify that measurement data quality objectives are met; and (4) Numerous LANL nuclear facilities support the nuclear material handling, preparation, and analysis capabilities necessary to evaluate samples containing nearly any mass of an actinide (attogram to kilogram levels).

  9. Water Supply at Los Alamos during 1997

    SciTech Connect

    M. N. Maes; S. G. McLin; W. D. Purtymun

    1998-12-01

    Production of potable municipal water supplies during 1997 totaled about 1,285.9 million gallons from wells in the Guaje, Pajarito, and Otowi well fields. There was no water used from the spring gallery in Water Canyon or from Guaje Reservoir during 1997. About 2.4 million gallons of water from Los Alamos Reservoir was used to irrigate public parks and recreational lands. The total water usage in 1997 was about 1,288.3 million gallons, or about 135 gallons per day per person living in Los Alamos County. Groundwater pumpage was down about 82.2 million gallons in 1997 compared with the pumpage in 1996. Four new replacement wells were drilled and cased in Guaje Canyon between October 1997 and March 1998. These wells are currently being developed and aquifer tests are being performed. A special report summarizing the geological, geophysical, and well construction logs will be issued in the near future for these new wells.

  10. Los Alamos Novel Rocket Design Flight Tested

    ScienceCinema

    Tappan, Bryce

    2016-07-12

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  11. Risk management at Los Alamos National Laboratory

    SciTech Connect

    Brooks, D.G.; Stack, D.W.

    1993-11-01

    Los Alamos National Laboratory has risk management programs at a number of administrative levels. Each line organization has responsibility for risk management for routine operations. The Facility Risk Management group (HS-3) is the Los Alamos organization with the primary responsibility for risk management including providing input and expertise to facilities and line managers in the management and documentation of ES&H hazards and risks associated with existing and new activities. One of the major contributions this group has made to laboratory risk management program is to develop and implement a hazard identification and classification methodology that is readily adaptable to continuously changing classification guidelines such as DOE-STD-1027. The increased emphasis on safety at Los Alamos has led to the formation of additional safety oversight organization such as the Integration and Coordination Office (ICO), which is responsible for prioritization of risk management activities. In the fall of 1991, nearly 170 DOE inspectors spent 6 weeks analyzing the environmental, safety, and health activities at Los Alamos. The result of this audit was a list of over 1000 findings, each indicating some deficiency in current Laboratory operations relative to DOE and other government regulation. The audit team`s findings were consolidated and ``action plans`` were developed to address the findings. This resulted in over 200 action plans with a total estimated cost of almost $1 billion. The Laboratory adopted a risk-based prioritization process to attempt to achieve as much risk reduction as possible with the available resources. This paper describes the risk based prioritization model that was developed.

  12. Los Alamos National Laboratory Facility Review

    SciTech Connect

    Nelson, Ronald Owen

    2015-06-05

    This series of slides depicts the Los Alamos Neutron Science Center (LANSCE). The Center's 800-MeV linac produces H+ and H- beams as well as beams of moderated (cold to 1 MeV) and unmoderated (0.1 to 600 MeV) neutrons. Experimental facilities and their capabilities and characteristics are outlined. Among these are LENZ, SPIDER, and DANCE.

  13. Los Alamos Team Demonstrates Bottle Scanner Technology

    SciTech Connect

    Espy, Michelle; Schultz, Larry

    2014-05-06

    Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

  14. Los Alamos Team Demonstrates Bottle Scanner Technology

    ScienceCinema

    Espy, Michelle; Schultz, Larry

    2016-07-12

    Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

  15. Amphibians and Reptiles of Los Alamos County

    SciTech Connect

    Teralene S. Foxx; Timothy K. Haarmann; David C. Keller

    1999-10-01

    Recent studies have shown that amphibians and reptiles are good indicators of environmental health. They live in terrestrial and aquatic environments and are often the first animals to be affected by environmental change. This publication provides baseline information about amphibians and reptiles that are present on the Pajarito Plateau. Ten years of data collection and observations by researchers at Los Alamos National Laboratory, the University of New Mexico, the New Mexico Department of Game and Fish, and hobbyists are represented.

  16. Los Alamos Novel Rocket Design Flight Tested

    SciTech Connect

    Tappan, Bryce

    2014-10-23

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  17. CONVERGENCE STUDIES OF MASS TRANSPORT IN DISKS WITH GRAVITATIONAL INSTABILITIES. II. THE RADIATIVE COOLING CASE

    SciTech Connect

    Steiman-Cameron, Thomas Y.; Durisen, Richard H.; Michael, Scott; McConnell, Caitlin R.; Boley, Aaron C. E-mail: durisen@astro.indiana.edu E-mail: carmccon@indiana.edu

    2013-05-10

    We conduct a convergence study of a protoplanetary disk subject to gravitational instabilities (GIs) at a time of approximate balance between heating produced by the GIs and radiative cooling governed by realistic dust opacities. We examine cooling times, characterize GI-driven spiral waves and their resultant gravitational torques, and evaluate how accurately mass transport can be represented by an {alpha}-disk formulation. Four simulations, identical except for azimuthal resolution, are conducted with a grid-based three-dimensional hydrodynamics code. There are two regions in which behaviors differ as resolution increases. The inner region, which contains 75% of the disk mass and is optically thick, has long cooling times and is well converged in terms of various measures of structure and mass transport for the three highest resolutions. The longest cooling times coincide with radii where the Toomre Q has its minimum value. Torques are dominated in this region by two- and three-armed spirals. The effective {alpha} arising from gravitational stresses is typically a few Multiplication-Sign 10{sup -3} and is only roughly consistent with local balance of heating and cooling when time-averaged over many dynamic times and a wide range of radii. On the other hand, the outer disk region, which is mostly optically thin, has relatively short cooling times and does not show convergence as resolution increases. Treatment of unstable disks with optical depths near unity with realistic radiative transport is a difficult numerical problem requiring further study. We discuss possible implications of our results for numerical convergence of fragmentation criteria in disk simulations.

  18. Critical partnerships: Los Alamos, universities, and industry

    SciTech Connect

    Berger, C.L.

    1997-04-01

    Los Alamos National Laboratory, situated 35 miles northwest of Santa Fe, NM, is one of the Department of Energy`s three Defense Programs laboratories. It encompasses 43 square miles, employees approximately 10,000 people, and has a budget of approximately $1.1B in FY97. Los Alamos has a strong post-cold war mission, that of reducing the nuclear danger. But even with that key role in maintaining the nation`s security, Los Alamos views partnerships with universities and industry as critical to its future well being. Why is that? As the federal budget for R&D comes under continued scrutiny and certain reduction, we believe that the triad of science and technology contributors to the national system of R&D must rely on and leverage each others capabilities. For us this means that we will rely on these partners to help us in 5 key ways: We expect that partnerships will help us maintain and enhance our core competencies. In doing so, we will be able to attract the best scientists and engineers. To keep on the cutting edge of research and development, we have found that partnerships maintain the excellence of staff through new and exciting challenges. Additionally, we find that from our university and corporate partners we often learn and incorporate {open_quotes}best practices{close_quotes} in organizational management and operations. Finally, we believe that a strong national system of R&D will ensure and enhance our ability to generate revenues.

  19. Los Alamos National Laboratory Building Cost Index

    SciTech Connect

    Orr, H.D.; Lemon, G.D.

    1983-01-01

    The Los Alamos National Laboratory Building Cost Index indicates that actual escalation since 1970 is near 10% per year. Therefore, the Laboratory will continue using a 10% per year escalation rate for construction estimates through 1985 and a slightly lower rate of 8% per year from 1986 through 1990. The computerized program compares the different elements involved in the cost of a typical construction project, which for our purposes, is a complex of office buildings and experimental laboratores. The input data used in the program consist primarily of labor costs and material and equipment costs. The labor costs are the contractural rates of the crafts workers in the Los Alamos area. For the analysis, 12 field-labor draft categories are used; each is weighted corresponding to the labor craft distribution associated with the typical construction project. The materials costs are current Los Alamos prices. Additional information sources include material and equipment quotes obtained through conversations with vendors and from trade publications. The material and equipment items separate into 17 categories for the analysis and are weighted corresponding to the material and equipment distribution associated with the typical construction project. The building cost index is compared to other national building cost indexes.

  20. Los Alamos National Laboratory building cost index

    SciTech Connect

    Orr, H.D.; Lemon, G.D.

    1982-10-01

    The Los Alamos National Laboratory Building Cost Index indicates that actual escalation since 1970 is near 10% per year. Therefore, the Laboratory will continue using a 10% per year escalation rate for construction estimates through 1985 and a slightly lower rate of 8% per year from 1986 through 1990. The computerized program compares the different elements involved in the cost of a typical construction project, which for our purposes, is a complex of office buildings and experimental laboratories. The input data used in the program consist primarily of labor costs and material and equipment costs. The labor costs are the contractual rates of the crafts workers in the Los Alamos area. For the analysis, 12 field-labor craft categories are used; each is weighted corresponding to the labor craft distribution associated with the typical construction project. The materials costs are current Los Alamos prices. Additional information sources include material and equipment quotes obtained through conversations with vendors and from trade publications. The material and equipment items separate into 17 categories for the analysis and are weighted corresponding to the material and equipment distribution associated with the typical construction project. The building cost index is compared to other national building cost indexes.

  1. Soot formation, transport, and radiation in unsteady diffusion flames : LDRD final report.

    SciTech Connect

    Suo-Anttila, Jill Marie; Williams, Timothy C.; Shaddix, Christopher R.; Jensen, Kirk A.; Blevins, Linda Gail; Kearney, Sean Patrick; Schefer, Robert W.

    2004-10-01

    Fires pose the dominant risk to the safety and security of nuclear weapons, nuclear transport containers, and DOE and DoD facilities. The thermal hazard from these fires primarily results from radiant emission from high-temperature flame soot. Therefore, it is necessary to understand the local transport and chemical phenomena that determine the distributions of soot concentration, optical properties, and temperature in order to develop and validate constitutive models for large-scale, high-fidelity fire simulations. This report summarizes the findings of a Laboratory Directed Research and Development (LDRD) project devoted to obtaining the critical experimental information needed to develop such constitutive models. A combination of laser diagnostics and extractive measurement techniques have been employed in both steady and pulsed laminar diffusion flames of methane, ethylene, and JP-8 surrogate burning in air. For methane and ethylene, both slot and coannular flame geometries were investigated, as well as normal and inverse diffusion flame geometries. For the JP-8 surrogate, coannular normal diffusion flames were investigated. Soot concentrations, polycyclic aromatic hydrocarbon (PAH) laser-induced fluorescence (LIF) signals, hydroxyl radical (OH) LIF, acetylene and water vapor concentrations, soot zone temperatures, and the velocity field were all successfully measured in both steady and unsteady versions of these various flames. In addition, measurements were made of the soot microstructure, soot dimensionless extinction coefficient (&), and the local radiant heat flux. Taken together, these measurements comprise a unique, extensive database for future development and validation of models of soot formation, transport, and radiation.

  2. GRAVE: An Interactive Geometry Construction and Visualization Software System for the TORT Nuclear Radiation Transport Code

    SciTech Connect

    Blakeman, E.D.

    2000-05-07

    A software system, GRAVE (Geometry Rendering and Visual Editor), has been developed at the Oak Ridge National Laboratory (ORNL) to perform interactive visualization and development of models used as input to the TORT three-dimensional discrete ordinates radiation transport code. Three-dimensional and two-dimensional visualization displays are included. Display capabilities include image rotation, zoom, translation, wire-frame and translucent display, geometry cuts and slices, and display of individual component bodies and material zones. The geometry can be interactively edited and saved in TORT input file format. This system is an advancement over the current, non-interactive, two-dimensional display software. GRAVE is programmed in the Java programming language and can be implemented on a variety of computer platforms. Three- dimensional visualization is enabled through the Visualization Toolkit (VTK), a free-ware C++ software library developed for geometric and data visual display. Future plans include an extension of the system to read inputs using binary zone maps and combinatorial geometry models containing curved surfaces, such as those used for Monte Carlo code inputs. Also GRAVE will be extended to geometry visualization/editing for the DORT two-dimensional transport code and will be integrated into a single GUI-based system for all of the ORNL discrete ordinates transport codes.

  3. HELIOSEISMIC TESTS OF THE NEW LOS ALAMOS OPACITIES

    SciTech Connect

    J. GUZIK; ET AL

    2001-01-01

    We compare the helioseismic properties of two solar models, one calibrated with the OPAL opacities and the other with the recent Los Alamos LEDCOP opacities. We show that, in the radiative interior of the Sun, the small differences between the two sets of opacities (up to 6% near the base of the convection zone) lead to noticeable differences in the solar structure (up to 0.4% in sound speed), with the OPAL model being the closest to the helioseismic data. More than half of the difference between the two opacity sets results from the interpolation scheme and from the relatively widely spaced temperature grids used in the tables. The remaining 3% intrinsic difference between the OPAL and the LEDCOP opacities in the radiative interior of the Sun is well within the error bars on the opacity calculations resulting from the uncertainties on the physics. We conclude that the OPAL and LEDCOP opacity sets do about as well in the radiative interior of the Sun.

  4. Solving Inverse Radiation Transport Problems with Multi-Sensor Data in the Presence of Correlated Measurement and Modeling Errors

    SciTech Connect

    Thomas, Edward V.; Stork, Christopher L.; Mattingly, John K.

    2015-07-01

    Inverse radiation transport focuses on identifying the configuration of an unknown radiation source given its observed radiation signatures. The inverse problem is traditionally solved by finding the set of transport model parameter values that minimizes a weighted sum of the squared differences by channel between the observed signature and the signature pre dicted by the hypothesized model parameters. The weights are inversely proportional to the sum of the variances of the measurement and model errors at a given channel. The traditional implicit (often inaccurate) assumption is that the errors (differences between the modeled and observed radiation signatures) are independent across channels. Here, an alternative method that accounts for correlated errors between channels is described and illustrated using an inverse problem based on the combination of gam ma and neutron multiplicity counting measurements.

  5. Transport of charge carriers through the thin base of a heterobipolar transistor under the impact of radiation

    SciTech Connect

    Puzanov, A. S. Obolenskii, S. V. Kozlov, V. A.

    2015-01-15

    The transport of electrons in heterobipolar transistors with radiation defects is studied under conditions where the characteristic sizes of defect clusters and the distances between them can be comparable or can even exceed the sizes of the device base. It is shown that, under some levels of irradiation, neutron radiation can bring about a decrease in the time of flight of hot electrons through the base, which retards the degradation of the transistor parameters.

  6. The Method of Manufactured Solutions for RattleSnake A SN Radiation Transport Solver Inside the MOOSE Framework

    SciTech Connect

    Yaqi Wang

    2012-06-01

    The Method of Manufactured Solutions (MMS) is an accepted technique to verify that a numerical discretization for the radiation transport equation has been implemented correctly. This technique offers a few advantages over other methods such as benchmark problems or analytical solutions. The solution can be manufactured such that properties for the angular flux are either stressed or preserved. For radiation transport, these properties can include desired smoothness, positiveness and arbitrary order of anisotropy in angle. Another advantage is that the angular flux solution can be manufactured for multidimensional problems where analytical solutions are difficult to obtain in general.

  7. Tests of local transport theory and reduced wall impurity influx with highly radiative plasmas in the Tokamak Fusion Test Reactor

    NASA Astrophysics Data System (ADS)

    Hill, K. W.; Scott, S. D.; Bell, M.; Budny, R.; Bush, C. E.; Clark, R. E. H.; Denne-Hinnov, B.; Ernst, D. R.; Hammett, G. W.; Mikkelsen, D. R.; Mueller, D.; Ongena, J.; Park, H. K.; Ramsey, A. T.; Synakowski, E. J.; Taylor, G.; Zarnstorff, M. C.

    1999-03-01

    The electron temperature (Te) profile in neutral beam-heated supershot plasmas (Te0˜6-7 keV ion temperature Ti0˜15-20 keV, beam power Pb˜16 MW) was remarkably invariant when radiative losses were increased significantly through gas puffing of krypton and xenon in the Tokamak Fusion Test Reactor [McGuire et al., Phys. Plasmas 2, 2176 (1995)]. Trace impurity concentrations (nz/ne˜10-3) generated almost flat and centrally peaked radiation profiles, respectively, and increased the radiative losses to 45%-90% of the input power (from the normal ˜25%). Energy confinement was not degraded at radiated power fractions up to 80%. A 20%-30% increase in Ti, in spite of an increase in ion-electron power loss, implies a factor of ˜3 drop in the local ion thermal diffusivity. These experiments form the basis for a nearly ideal test of transport theory, since the change in the beam heating power profile is modest, while the distribution of power flow between (1) radiation and (2) conduction plus convection changes radically and is locally measurable. The decrease in Te was significantly less than predicted by two transport models and may provide important tests of more complete transport models. At input power levels of 30 MW, the increased radiation eliminated the catastrophic carbon influx (carbon "bloom") and performance (energy confinement and neutron production) was improved significantly relative to that of matched shots without impurity gas puffing.

  8. X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

    DOE PAGES

    Fournier, K. B.; Brown, Jr., C. G.; Yeoman, M. F.; ...

    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

  9. X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

    SciTech Connect

    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.; Gilliam, R. P.; Froula, N.; Lilly, M.; Davis, J. F.; Lerch, MAJ. A.; Blue, B. E.

    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. We discuss the measured accuracy of sample responses, as well as planned modifications to the XTRRA cassette.

  10. Electromagnetic radiation influence on nonlinear charge and energy transport in biosystems.

    PubMed

    Brizhik, L; Cruzeiro-Hansson, L; Eremko, A

    1999-06-01

    The influence of electromagnetic radiation (EMR) on charge and energy transport processes in biological systems is studied in the light of the soliton model. It is shown that in the spectrum of biological effects of EMR there are two frequency resonances corresponding to qualitatively different frequency dependent effects of EMR on solitons. One of them is connected with the quasiresonance dynamic response of solitons to the EMR. At EMR frequencies close to the dynamic resonance frequency the solitons absorb energy from the field and generate intensive vibrational modes in the macromolecule. The second EMR resonance is connected with soliton decay due to the quantum mechanical transition of the system from the bound soliton state into the excited unbound states.

  11. Radiation transport calculations on unstructured grids using a spatially decomposed and threaded algorithm

    SciTech Connect

    Nemanic, M K; Nowak, P

    1999-04-12

    We consider the solution of time-dependent, energy-dependent, discrete ordinates, and nonlinear radiative transfer problems on three-dimensional unstructured spatial grids. We discuss the solution of this class of transport problems, using the code TETON, on large distributed-memory multinode computers having multiple processors per ''node'' (e.g. the IBM-SP). We discuss the use of both spatial decomposition using message passing between ''nodes'' and a threading algorithm in angle on each ''node''. We present timing studies to show how this algorithm scales to hundreds and thousands of processors. We also present an energy group ''batching'' algorithm that greatly enhances cache performance. Our conclusion, after considering cache performance, storage limitations and dependencies inherent in the physics, is that a model that uses a combination of message-passing and threading is superior to one that uses message-passing alone. We present numerical evidence to support our conclusion.

  12. Development and validation of a GEANT4 radiation transport code for CT dosimetry.

    PubMed

    Carver, D E; Kost, S D; Fernald, M J; Lewis, K G; Fraser, N D; Pickens, D R; Price, R R; Stabin, M G

    2015-04-01

    The authors have created a radiation transport code using the GEANT4 Monte Carlo toolkit to simulate pediatric patients undergoing CT examinations. The focus of this paper is to validate their simulation with real-world physical dosimetry measurements using two independent techniques. Exposure measurements were made with a standard 100-mm CT pencil ionization chamber, and absorbed doses were also measured using optically stimulated luminescent (OSL) dosimeters. Measurements were made in air with a standard 16-cm acrylic head phantom and with a standard 32-cm acrylic body phantom. Physical dose measurements determined from the ionization chamber in air for 100 and 120 kVp beam energies were used to derive photon-fluence calibration factors. Both ion chamber and OSL measurement results provide useful comparisons in the validation of the Monte Carlo simulations. It was found that simulated and measured CTDI values were within an overall average of 6% of each other.

  13. Non-randomized mtDNA damage after ionizing radiation via charge transport

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; Liu, Xinguo; Zhang, Xin; Zhou, Rong; He, Yang; Li, Qiang; Wang, Zhenhua; Zhang, Hong

    2012-10-01

    Although it is well known that there are mutation hot spots in mtDNA, whether there are damage hot spots remain elusive. In this study, the regional DNA damage of mitochondrial genome after ionizing radiation was determined by real-time quantitative PCR. The mtDNA damage level was found to be dose-dependent and regional unequal. The control region was the most susceptible region to oxidative damage. GGG, as an typical hole trap during charge transport, was found to be disproportionally enriched in the control region. A total of 107 vertebrate mitochondrial genomes were then analyzed to testify whether the GGG enrichment in control region was evolutionary conserved. Surprisingly, the triple G enrichment can be observed in most of the homeothermal animals, while the majority of heterothermic animals showed no triple G enrichment. These results indicated that the triple G enrichment in control region was related to the mitochondrial metabolism during evolution.

  14. Implementation, capabilities, and benchmarking of Shift, a massively parallel Monte Carlo radiation transport code

    NASA Astrophysics Data System (ADS)

    Pandya, Tara M.; Johnson, Seth R.; Evans, Thomas M.; Davidson, Gregory G.; Hamilton, Steven P.; Godfrey, Andrew T.

    2016-03-01

    This work discusses the implementation, capabilities, and validation of Shift, a massively parallel Monte Carlo radiation transport package authored at Oak Ridge National Laboratory. Shift has been developed to scale well from laptops to small computing clusters to advanced supercomputers and includes features such as support for multiple geometry and physics engines, hybrid capabilities for variance reduction methods such as the Consistent Adjoint-Driven Importance Sampling methodology, advanced parallel decompositions, and tally methods optimized for scalability on supercomputing architectures. The scaling studies presented in this paper demonstrate good weak and strong scaling behavior for the implemented algorithms. Shift has also been validated and verified against various reactor physics benchmarks, including the Consortium for Advanced Simulation of Light Water Reactors' Virtual Environment for Reactor Analysis criticality test suite and several Westinghouse AP1000® problems presented in this paper. These benchmark results compare well to those from other contemporary Monte Carlo codes such as MCNP5 and KENO.

  15. Accelerating execution of the integrated TIGER series Monte Carlo radiation transport codes

    SciTech Connect

    Smith, L.M.; Hochstedler, R.D.

    1997-02-01

    Execution of the integrated TIGER series (ITS) of coupled electron/photon Monte Carlo radiation transport codes has been accelerated by modifying the FORTRAN source code for more efficient computation. Each member code of ITS was benchmarked and profiled with a specific test case that directed the acceleration effort toward the most computationally intensive subroutines. Techniques for accelerating these subroutines included replacing linear search algorithms with binary versions, replacing the pseudo-random number generator, reducing program memory allocation, and proofing the input files for geometrical redundancies. All techniques produced identical or statistically similar results to the original code. Final benchmark timing of the accelerated code resulted in speed-up factors of 2.00 for TIGER (the one-dimensional slab geometry code), 1.74 for CYLTRAN (the two-dimensional cylindrical geometry code), and 1.90 for ACCEPT (the arbitrary three-dimensional geometry code).

  16. An object-oriented implementation of a parallel Monte Carlo code for radiation transport

    NASA Astrophysics Data System (ADS)

    Santos, Pedro Duarte; Lani, Andrea

    2016-05-01

    This paper describes the main features of a state-of-the-art Monte Carlo solver for radiation transport which has been implemented within COOLFluiD, a world-class open source object-oriented platform for scientific simulations. The Monte Carlo code makes use of efficient ray tracing algorithms (for 2D, axisymmetric and 3D arbitrary unstructured meshes) which are described in detail. The solver accuracy is first verified in testcases for which analytical solutions are available, then validated for a space re-entry flight experiment (i.e. FIRE II) for which comparisons against both experiments and reference numerical solutions are provided. Through the flexible design of the physical models, ray tracing and parallelization strategy (fully reusing the mesh decomposition inherited by the fluid simulator), the implementation was made efficient and reusable.

  17. X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Fournier, K. B.; Brown, C. G.; Yeoman, M. F.; Fisher, J. H.; Seiler, S. W.; Hinshelwood, D.; Compton, S.; Holdener, F. R.; Kemp, G. E.; Newlander, C. D.; Gilliam, R. P.; Froula, N.; Lilly, M.; Davis, J. F.; Lerch, MAJ. A.; Blue, B. E.

    2016-11-01

    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 National Ignition Facility'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. The measured accuracy of sample responses as well as planned modifications to the XTRRA cassette is discussed.

  18. Finite element approximation of the radiative transport equation in a medium with piece-wise constant refractive index

    SciTech Connect

    Lehtikangas, O.; Tarvainen, T.; Kim, A.D.; Arridge, S.R.

    2015-02-01

    The radiative transport equation can be used as a light transport model in a medium with scattering particles, such as biological tissues. In the radiative transport equation, the refractive index is assumed to be constant within the medium. However, in biomedical media, changes in the refractive index can occur between different tissue types. In this work, light propagation in a medium with piece-wise constant refractive index is considered. Light propagation in each sub-domain with a constant refractive index is modeled using the radiative transport equation and the equations are coupled using boundary conditions describing Fresnel reflection and refraction phenomena on the interfaces between the sub-domains. The resulting coupled system of radiative transport equations is numerically solved using a finite element method. The approach is tested with simulations. The results show that this coupled system describes light propagation accurately through comparison with the Monte Carlo method. It is also shown that neglecting the internal changes of the refractive index can lead to erroneous boundary measurements of scattered light.

  19. Radiative Effect of Clouds on Tropospheric Chemistry in a Global Three-Dimensional Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Liu, Hongyu; Crawford, James H.; Pierce, Robert B.; Norris, Peter; Platnick, Steven E.; Chen, Gao; Logan, Jennifer A.; Yantosca, Robert M.; Evans, Mat J.; Kittaka, Chieko; Feng, Yan; Tie, Xuexi

    2006-01-01

    Clouds exert an important influence on tropospheric photochemistry through modification of solar radiation that determines photolysis frequencies (J-values). We assess the radiative effect of clouds on photolysis frequencies and key oxidants in the troposphere with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations from the Goddard Earth Observing System data assimilation system (GEOS DAS) at the NASA Global Modeling and Assimilation Office (GMAO). We focus on the year of 2001 with the GEOS-3 meteorological observations. Photolysis frequencies are calculated using the Fast-J radiative transfer algorithm. The GEOS-3 global cloud optical depth and cloud fraction are evaluated and generally consistent with the satellite retrieval products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the International Satellite Cloud Climatology Project (ISCCP). Results using the linear assumption, which assumes linear scaling of cloud optical depth with cloud fraction in a grid box, show global mean OH concentrations generally increase by less than 6% because of the radiative effect of clouds. The OH distribution shows much larger changes (with maximum decrease of approx.20% near the surface), reflecting the opposite effects of enhanced (weakened) photochemistry above (below) clouds. The global mean photolysis frequencies for J[O1D] and J[NO2] in the troposphere change by less than 5% because of clouds; global mean O3 concentrations in the troposphere increase by less than 5%. This study shows tropical upper tropospheric O3 to be less sensitive to the radiative effect of clouds than previously reported (approx.5% versus approx.20-30%). These results emphasize that the dominant effect of clouds is to influence the vertical redistribution of the intensity of photochemical activity while global average effects remain modest, again contrasting with previous studies. Differing vertical distributions

  20. The Deep Impact of Cloud Turbulence (and Microphysics) on Solar Radiation Transport: An Asymptotic Scaling Analysis

    NASA Astrophysics Data System (ADS)

    Davis, A. B.

    2007-05-01

    transmission spectroscopy and numerical simulations are used to assess the relevance of the new asymptotic scaling relations to the real atmosphere. An interesting evolution of the mean-field radiation transport model ensues. The analytic theory remains qualitatively correct and makes important predictions for the impact of spatially variable cloudiness on path length statistics for reflected sunlight. Such observations will become available none to soon in 2008 when NASA's Orbiting Carbon Observatory (OCO) carries first high-resolution oxygen A-band spectrometer into space.

  1. Trend of surface solar radiation over Asia simulated by aerosol transport-climate model

    NASA Astrophysics Data System (ADS)

    Takemura, T.; Ohmura, A.

    2009-12-01

    Long-term records of surface radiation measurements indicate a decrease in the solar radiation between the 1950s and 1980s (“global dimming”), then its recovery afterward (“global brightening”) at many locations all over the globe [Wild, 2009]. On the other hand, the global brightening is delayed over the Asian region [Ohmura, 2009]. It is suggested that these trends of the global dimming and brightening are strongly related with a change in aerosol loading in the atmosphere which affect the climate change through the direct, semi-direct, and indirect effects. In this study, causes of the trend of the surface solar radiation over Asia during last several decades are analyzed with an aerosol transport-climate model, SPRINTARS. SPRINTARS is coupled with MIROC which is a general circulation model (GCM) developed by Center for Climate System Research (CCSR)/University of Tokyo, National Institute for Environmental Studies (NIES), and Frontier Research Center for Global Change (FRCGC) [Takemura et al., 2000, 2002, 2005, 2009]. The horizontal and vertical resolutions are T106 (approximately 1.1° by 1.1°) and 56 layers, respectively. SPRINTARS includes the transport, radiation, cloud, and precipitation processes of all main tropospheric aerosols (black and organic carbons, sulfate, soil dust, and sea salt). The model treats not only the aerosol mass mixing ratios but also the cloud droplet and ice crystal number concentrations as prognostic variables, and the nucleation processes of cloud droplets and ice crystals depend on the number concentrations of each aerosol species. Changes in the cloud droplet and ice crystal number concentrations affect the cloud radiation and precipitation processes in the model. Historical emissions, that is consumption of fossil fuel and biofuel, biomass burning, aircraft emissions, and volcanic eruptions are prescribed from database provided by the Aerosol Model Intercomparison Project (AeroCom) and the latest IPCC inventories

  2. CSDUST3 - A radiation transport code for a dusty medium with 1-D planar, spherical or cylindrical geometry

    NASA Technical Reports Server (NTRS)

    Egan, Michael P.; Leung, Chun Ming; Spagna, George F., Jr.

    1988-01-01

    The program solves the radiation transport problem in a dusty medium with one-dimensional planar, spherical or cylindrical geometry. It determines self-consistently the effects of multiple scattering, absorption, and re-emission of photons on the temperature of dust grains and the characteristics of the internal radiation field. The program can treat radiation field anisotropy, linear anisotropic scattering, and multi-grain components. The program output consists of the dust-temperature distribution, flux spectrum, surface brightness at each frequency and the observed intensities (involving a convolution with a telescope beam pattern).

  3. Evaluation of a radiation transport modeling method for radioactive bone cement

    NASA Astrophysics Data System (ADS)

    Kaneko, T. S.; Sehgal, V.; Skinner, H. B.; Al-Ghazi, M. S. A. L.; Ramisinghani, N. S.; Keyak, J. H.

    2010-05-01

    Spinal metastases are a common and serious manifestation of cancer, and are often treated with vertebroplasty/kyphoplasty followed by external beam radiation therapy (EBRT). As an alternative, we have introduced radioactive bone cement, i.e. bone cement incorporated with a radionuclide. In this study, we present a Monte Carlo radiation transport modeling method to calculate dose distributions within vertebrae containing radioactive cement. Model accuracy was evaluated by comparing model-predicted depth-dose curves to those measured experimentally in eight cadaveric vertebrae using radiochromic film. The high-gradient regions of the depth-dose curves differed by radial distances of 0.3-0.9 mm, an improvement over EBRT dosimetry accuracy. The low-gradient regions differed by 0.033-0.055 Gy/h/mCi, which may be important in situations involving prior spinal cord irradiation. Using a more rigorous evaluation of model accuracy, four models predicted the measured dose distribution within the experimental uncertainty, as represented by the 95% confidence interval of the measured log-linear depth-dose curve. The remaining four models required modification to account for marrow lost from the vertebrae during specimen preparation. However, the accuracy of the modified model results indicated that, when this source of uncertainty is accounted for, this modeling method can be used to predict dose distributions in vertebrae containing radioactive cement.

  4. Simulation of decay processes and radiation transport times in radioactivity measurements

    NASA Astrophysics Data System (ADS)

    García-Toraño, E.; Peyres, V.; Bé, M.-M.; Dulieu, C.; Lépy, M.-C.; Salvat, F.

    2017-04-01

    The Fortran subroutine package PENNUC, which simulates random decay pathways of radioactive nuclides, is described. The decay scheme of the active nuclide is obtained from the NUCLEIDE database, whose web application has been complemented with the option of exporting nuclear decay data (possible nuclear transitions, branching ratios, type and energy of emitted particles) in a format that is readable by the simulation subroutines. In the case of beta emitters, the initial energy of the electron or positron is sampled from the theoretical Fermi spectrum. De-excitation of the atomic electron cloud following electron capture and internal conversion is described using transition probabilities from the LLNL Evaluated Atomic Data Library and empirical or calculated energies of released X rays and Auger electrons. The time evolution of radiation showers is determined by considering the lifetimes of nuclear and atomic levels, as well as radiation propagation times. Although PENNUC is designed to operate independently, here it is used in conjunction with the electron-photon transport code PENELOPE, and both together allow the simulation of experiments with radioactive sources in complex material structures consisting of homogeneous bodies limited by quadric surfaces. The reliability of these simulation tools is demonstrated through comparisons of simulated and measured energy spectra from radionuclides with complex multi-gamma spectra, nuclides with metastable levels in their decay pathways, nuclides with two daughters, and beta plus emitters.

  5. Benchmarks and models for 1-D radiation transport in stochastic participating media

    SciTech Connect

    Miller, David Scott

    2000-08-01

    Benchmark calculations for radiation transport coupled to a material temperature equation in a 1-D slab and 1-D spherical geometry binary random media are presented. The mixing statistics are taken to be homogeneous Markov statistics in the 1-D slab but only approximately Markov statistics in the 1-D sphere. The material chunk sizes are described by Poisson distribution functions. The material opacities are first taken to be constant and then allowed to vary as a strong function of material temperature. Benchmark values and variances for time evolution of the ensemble average of material temperature energy density and radiation transmission are computed via a Monte Carlo type method. These benchmarks are used as a basis for comparison with three other approximate methods of solution. One of these approximate methods is simple atomic mix. The second approximate model is an adaptation of what is commonly called the Levermore-Pomraning model and which is referred to here as the standard model. It is shown that recasting the temperature coupling as a type of effective scattering can be useful in formulating the third approximate model, an adaptation of a model due to Su and Pomraning which attempts to account for the effects of scattering in a stochastic context. This last adaptation shows consistent improvement over both the atomic mix and standard models when used in the 1-D slab geometry but shows limited improvement in the 1-D spherical geometry. Benchmark values are also computed for radiation transmission from the 1-D sphere without material heating present. This is to evaluate the performance of the standard model on this geometry--something which has never been done before. All of the various tests demonstrate the importance of stochastic structure on the solution. Also demonstrated are the range of usefulness and limitations of a simple atomic mix formulation.

  6. Benchmarks and models for 1-D radiation transport in stochastic participating media

    NASA Astrophysics Data System (ADS)

    Miller, David Scott

    Benchmark calculations for radiation transport coupled to a material temperature equation in a 1-D slab and 1-D spherical geometry binary random media are presented. The mixing statistics are taken to be homogeneous Markov statistics in the 1-D slab but only approximately Markov statistics in the 1-D sphere. The material chunk sizes are described by Poisson distribution functions. The material opacities are first taken to be constant and then allowed to vary as a strong function of material temperature. Benchmark values and variances for time evolution of the ensemble average of material temperature energy density and radiation transmission are computed via a Monte Carlo type method. These benchmarks are used as a basis for comparison with three other approximate methods of solution. One of these approximate methods is simple atomic mix. The second approximate model is an adaptation of what is commonly called the Levermore-Pomraning model and which is referred to here as the standard model. It is shown that recasting the temperature coupling as a type of effective scattering can be useful in formulating the third approximate model, an adaptation of a model due to Su and Pomraning which attempts to account for the effects of scattering in a stochastic context. This last adaptation shows consistent improvement over both the atomic mix and standard models when used in the 1-D slab geometry but shows limited improvement in the 1-D spherical geometry. Benchmark values are also computed for radiation transmission from the 1-D sphere without material heating present. This is to evaluate the performance of the standard model on this geometry-something which has never been done before. All of the various tests demonstrate the importance of stochastic structure on the solution. Also demonstrated are the range of usefulness and limitations of a simple atomic mix formulation.

  7. Transport, radiative, and dynamical effects of the antarctic ozone hole: A GFDL SKYHI' model experiment

    SciTech Connect

    Mahlman, J.D; Umscheid, L.J. ); Pinto, J.P. )

    1994-02-15

    The GFDL SKYHI' general circulation model has been used to simulate the effect of the Antarctic ozone hole' phenomenon on the radiative and dynamical environment of the lower stratosphere. Both the polar ozone destruction and photochemical restoration chemistries are calculated by parameterized simplifications of the still somewhat uncertain chemical processes. The modeled total column ozone depletions are near 25% in spring over Antarctica, with 1% depletion reaching equatorial latitudes by the end of the 4 1/2-year model experiment. In the lower stratosphere, ozone reductions of 5% reach to the equator. Large coolings of about 8 K are simulated in the lower stratospheric over Antarctica in late spring, while a general cooling of about 1-1.5 K is present throughout the Southern Hemisphere lower stratosphere. The model atmosphere experiences a long-term positive temperature-chemical feedback because significant ozone reductions carry over into the next winter. The overall temperature response to the reduced ozone is essentially radiative in character. However, substantial dynamical changes are induced by the ozone hole effect. The Antarctic middle stratosphere in late spring warms by about 6 K over Antarctica and the lower midlatitude stratosphere warms by approximately 1 K. These warming spots are produced mainly by an increased residual circulation intensity. Also, the Antarctic vortex becomes tighter and more confined as a result of the reduced ozone. These two dynamical effects combine to steepen the meridional slope of quasi-conservative trace constituent isolines. Thus, the entire transport, radiative, and dynamical climatology of the springtime stratosphere is affected to an important degree by the ozone hole phenomenon. Over the entire year, however, these dynamical effects are considerably smaller. 27 refs., 13 figs.

  8. C5 Benchmark Problem with Discrete Ordinate Radiation Transport Code DENOVO

    SciTech Connect

    Yesilyurt, Gokhan; Clarno, Kevin T; Evans, Thomas M; Davidson, Gregory G; Fox, Patricia B

    2011-01-01

    The C5 benchmark problem proposed by the Organisation for Economic Co-operation and Development/Nuclear Energy Agency was modeled to examine the capabilities of Denovo, a three-dimensional (3-D) parallel discrete ordinates (S{sub N}) radiation transport code, for problems with no spatial homogenization. Denovo uses state-of-the-art numerical methods to obtain accurate solutions to the Boltzmann transport equation. Problems were run in parallel on Jaguar, a high-performance supercomputer located at Oak Ridge National Laboratory. Both the two-dimensional (2-D) and 3-D configurations were analyzed, and the results were compared with the reference MCNP Monte Carlo calculations. For an additional comparison, SCALE/KENO-V.a Monte Carlo solutions were also included. In addition, a sensitivity analysis was performed for the optimal angular quadrature and mesh resolution for both the 2-D and 3-D infinite lattices of UO{sub 2} fuel pin cells. Denovo was verified with the C5 problem. The effective multiplication factors, pin powers, and assembly powers were found to be in good agreement with the reference MCNP and SCALE/KENO-V.a Monte Carlo calculations.

  9. Improved non-local electron thermal transport model for two-dimensional radiation hydrodynamics simulations

    SciTech Connect

    Cao, Duc; Moses, Gregory; Delettrez, Jacques

    2015-08-15

    An implicit, non-local thermal conduction algorithm based on the algorithm developed by Schurtz, Nicolai, and Busquet (SNB) [Schurtz et al., Phys. Plasmas 7, 4238 (2000)] for non-local electron transport is presented and has been implemented in the radiation-hydrodynamics code DRACO. To study the model's effect on DRACO's predictive capability, simulations of shot 60 303 from OMEGA are completed using the iSNB model, and the computed shock speed vs. time is compared to experiment. Temperature outputs from the iSNB model are compared with the non-local transport model of Goncharov et al. [Phys. Plasmas 13, 012702 (2006)]. Effects on adiabat are also examined in a polar drive surrogate simulation. Results show that the iSNB model is not only capable of flux-limitation but also preheat prediction while remaining numerically robust and sacrificing little computational speed. Additionally, the results provide strong incentive to further modify key parameters within the SNB theory, namely, the newly introduced non-local mean free path. This research was supported by the Laboratory for Laser Energetics of the University of Rochester.

  10. A Deterministic Electron, Photon, Proton and Heavy Ion Radiation Transport Suite for the Study of the Jovian System

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Badavi, Francis F.; Blattnig, Steve R.; Atwell, William

    2011-01-01

    A deterministic suite of radiation transport codes, developed at NASA Langley Research Center (LaRC), which describe the transport of electrons, photons, protons, and heavy ions in condensed media is used to simulate exposures from spectral distributions typical of electrons, protons and carbon-oxygen-sulfur (C-O-S) trapped heavy ions in the Jovian radiation environment. The particle transport suite consists of a coupled electron and photon deterministic transport algorithm (CEPTRN) and a coupled light particle and heavy ion deterministic transport algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means for the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, proton and heavy ion radiation exposure assessments in complex space structures. In this paper, the radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron spectra of the Jovian environment as generated by the Jet Propulsion Laboratory (JPL) Galileo Interim Radiation Electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter System Mission (EJSM), the 105 days at Europa mission fluence energy spectra provided by JPL is used to produce the corresponding dose-depth curve in silicon behind an aluminum shield of 100 mils ( 0.7 g/sq cm). The transport suite can also accept ray-traced thickness files from a computer-aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point. In that regard, using a low-fidelity CAD model of the Galileo probe, the transport suite was verified by comparing with Monte Carlo (MC) simulations for orbits JOI--J35 of the Galileo extended mission (1996-2001). For the upcoming EJSM mission with a potential launch date of 2020, the transport suite is used to compute

  11. Transport and Mixing Patterns over Central California during the Carbonaceous Aerosol and Radiative Effects Study (CARES)

    SciTech Connect

    Fast, Jerome D.; Gustafson, William I.; Berg, Larry K.; Shaw, William J.; Pekour, Mikhail S.; Shrivastava, ManishKumar B.; Barnard, James C.; Ferrare, R.; Hostetler, Chris A.; Hair, John; Erickson, Matthew H.; Jobson, Tom; Flowers, Bradley; Dubey, Manvendra K.; Springston, Stephen R.; Pirce, Bradley R.; Dolislager, Leon; Pederson, J. R.; Zaveri, Rahul A.

    2012-02-17

    We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scales flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin Valley

  12. Transport and mixing patterns over Central California during the carbonaceous aerosol and radiative effects study (CARES)

    SciTech Connect

    Fast J. D.; Springston S.; Gustafson Jr., W. I.; Berg, L. K.; Shaw, W. J.; Pekour, M.; Shrivastava, M.; Barnard, J. C.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. A.; Erickson, M.; Jobson, B. T.; Flowers, B.; Dubey, M. K.; Pierce, R. B.; Dolislager, L.; Pederson, J.; Zaveri, R. A.

    2012-02-17

    We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scale flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 time periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin

  13. Conditions for coherent-synchrotron-radiation-induced microbunching suppression in multibend beam transport or recirculation arcs

    NASA Astrophysics Data System (ADS)

    Tsai, C.-Y.; Di Mitri, S.; Douglas, D.; Li, R.; Tennant, C.

    2017-02-01

    The coherent synchrotron radiation (CSR) of a high-brightness electron beam traversing a series of dipoles, such as transport or recirculation arcs, may result in beam phase space degradation. On one hand, CSR can perturb electron transverse motion in dispersive regions along the beam line and possibly cause emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching instability. For transport arcs, several schemes have been proposed to suppress the CSR-induced emittance growth. Correspondingly, a few scenarios have been introduced to suppress CSR-induced microbunching instability, which however mostly aim for linac-based machines. In this paper we provide sufficient conditions for suppression of CSR-induced microbunching instability along transport or recirculation arcs. Examples are presented with the relevant microbunching analyses carried out by our developed semianalytical Vlasov solver [C.-Y. Tsai, D. Douglas, R. Li, and C. Tennant, Linear microbunching analysis for recirculation machines, Phys. Rev. ST Accel. Beams 19, 114401 (2016), 10.1103/PhysRevAccelBeams.19.114401]. The example lattices include low-energy (˜100 MeV ) and high-energy (˜1 GeV ) recirculation arcs, and medium-energy compressor arcs. Our studies show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. Beam current dependences of maximal CSR microbunching gains are also demonstrated, which should help outline a beam line design for different scales of nominal currents. We expect this analysis can shed light on the lattice design approach that aims to control the CSR-induced microbunching.

  14. Los Alamos National Laboratory computer benchmarking 1982

    SciTech Connect

    Martin, J.L.

    1983-06-01

    Evaluating the performance of computing machinery is a continual effort of the Computer Research and Applications Group of the Los Alamos National Laboratory. This report summarizes the results of the group's benchmarking activities performed between October 1981 and September 1982, presenting compilation and execution times as well as megaflop rates for a set of benchmark codes. Tests were performed on the following computers: Cray Research, Inc. (CRI) Cray-1S; Control Data Corporation (CDC) 7600, 6600, Cyber 73, Cyber 825, Cyber 835, Cyber 855, and Cyber 205; Digital Equipment Corporation (DEC) VAX 11/780 and VAX 11/782; and Apollo Computer, Inc., Apollo.

  15. Los Alamos National Laboratory strategic directions

    SciTech Connect

    Hecker, S.

    1995-10-01

    It is my pleasure to welcome you to Los Alamos. I like the idea of bringing together all aspects of the research community-defense, basic science, and industrial. It is particularly important in today`s times of constrained budgets and in fields such as neutron research because I am convinced that the best science and the best applications will come from their interplay. If we do the science well, then we will do good applications. Keeping our eye focused on interesting applications will spawn new areas of science. This interplay is especially critical, and it is good to have these communities represented here today.

  16. Environmental Programs at Los Alamos National Laboratory

    SciTech Connect

    Jones, Patricia

    2012-07-11

    Summary of this project is: (1) Teamwork, partnering to meet goals - (a) Building on cleanup successes, (b) Solving legacy waste problems, (c) Protecting the area's environment; (2) Strong performance over the past three years - (a) Credibility from four successful Recovery Act Projects, (b) Met all Consent Order milestones, (c) Successful ramp-up of TRU program; (3) Partnership between the National Nuclear Security Administration's Los Alamos Site Office, DOE Carlsbad Field Office, New Mexico Environment Department, and contractor staff enables unprecedented cleanup progress; (4) Continued focus on protecting water resources; and (5) All consent order commitments delivered on time or ahead of schedule.

  17. Biological assessment for the effluent reduction program, Los Alamos National Laboratory, Los Alamos, New Mexico

    SciTech Connect

    Cross, S.P.

    1996-08-01

    This report describes the biological assessment for the effluent recution program proposed to occur within the boundaries of Los Alamos National Laboratory. Potential effects on wetland plants and on threatened and endangered species are discussed, along with a detailed description of the individual outfalls resulting from the effluent reduction program.

  18. LAMPF II workshop, Los Alamos National Laboratory, Los Alamos, New Mexico, February 1-4, 1982

    SciTech Connect

    Thiessen, H.A.

    1982-01-01

    This report contains the proceedings of the first LAMPF II Workshop held at Los Alamos February 1 to 4, 1982. Included are the talks that were available in written form. The conclusion of the participants was that there are many exciting areas of physics that will be addressed by such a machine.

  19. Aerosol distributions and radiative forcing over the Asian Pacific region simulated by Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS)

    NASA Astrophysics Data System (ADS)

    Takemura, Toshihiko; Nakajima, Teruyuki; Higurashi, Akiko; Ohta, Sachio; Sugimoto, Nobuo

    2003-12-01

    A three-dimensional aerosol transport-radiation model coupled with a general circulation model, Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS), simulates atmospheric aerosol distributions and optical properties. The simulated results are compared with aerosol sampling and optical observations from ground, aircraft, and satellite acquired by intensive observation campaigns over east Asia in spring 2001. Temporal variations of the aerosol concentrations, optical thickness, and Ångström exponent are in good agreement between the simulation and observations. The midrange values of the Ångström exponent, even at the Asian dust storm events over the outflow regions, suggest that the contribution of the anthropogenic aerosol, such as carbonaceous and sulfate, to the total optical thickness is of an order comparable to that of the Asian dust. The radiative forcing by the aerosol direct and indirect effects is also calculated. The negative direct radiative forcing is simulated to be over -10 W m-2 at the tropopause in the air mass during the large-scale dust storm, to which both anthropogenic aerosols and Asian dust contribute almost equivalently. The direct radiative forcing, however, largely depends on the cloud water content and the vertical profiles of aerosol and cloud. The simulation shows that not only sulfate and sea salt aerosols but also black carbon and soil dust aerosols, which absorb solar and thermal radiation, make strong negative radiative forcing by the direct effect at the surface, which may exceed the positive forcing by anthropogenic greenhouse gases over the east Asian region.

  20. Sound speed and oscillation frequencies for solar models evolved with Los Alamos ATOMIC opacities

    NASA Astrophysics Data System (ADS)

    Guzik, Joyce A.; Fontes, C. J.; Walczak, P.; Wood, S. R.; Mussack, K.; Farag, E.

    Los Alamos National Laboratory has calculated a new generation of radiative opacities (OPLIB data using the ATOMIC code) for elements with atomic number Z = 1-30 with improved physics input, updated atomic data, and finer temperature grid to replace the Los Alamos LEDCOP opacities released in the year 2000. We calculate the evolution of standard solar models including these new opacities, and compare with models evolved using the Lawrence Livermore National Laboratory OPAL opacities (Iglesias & Rogers 1996). We use the solar abundance mixture of Asplund et al. 2009. The Los Alamos ATOMIC opacities (Colgan et al. 2013a, 2013b, 2015) have steeper opacity derivatives than those of OPAL for temperatures and densities of the solar interior radiative zone. We compare the calculated nonadiabatic solar oscillation frequencies and solar interior sound speed to observed frequencies and helioseismic inferences. The calculated sound-speed profiles are similar for models evolved using either the updated Iben evolution code (see Guzik & Mussack 2010), or the MESA evolution code (Paxton et al. 2015). The LANL ATOMIC opacities partially mitigate the `solar abundance problem'.

  1. NEQAIRv14.0 Release Notes: Nonequilibrium and Equilibrium Radiative Transport Spectra Program

    NASA Technical Reports Server (NTRS)

    Brandis, Aaron Michael; Cruden, Brett A.

    2014-01-01

    NEQAIR v14.0 is the first parallelized version of NEQAIR. Starting from the last version of the code that went through the internal software release process at NASA Ames (NEQAIR 2008), there have been significant updates to the physics in the code and the computational efficiency. NEQAIR v14.0 supersedes NEQAIR v13.2, v13.1 and the suite of NEQAIR2009 versions. These updates have predominantly been performed by Brett Cruden and Aaron Brandis from ERC Inc at NASA Ames Research Center in 2013 and 2014. A new naming convention is being adopted with this current release. The current and future versions of the code will be named NEQAIR vY.X. The Y will refer to a major release increment. Minor revisions and update releases will involve incrementing X. This is to keep NEQAIR more in line with common software release practices. NEQAIR v14.0 is a standalone software tool for line-by-line spectral computation of radiative intensities and/or radiative heat flux, with one-dimensional transport of radiation. In order to accomplish this, NEQAIR v14.0, as in previous versions, requires the specification of distances (in cm), temperatures (in K) and number densities (in parts/cc) of constituent species along lines of sight. Therefore, it is assumed that flow quantities have been extracted from flow fields computed using other tools, such as CFD codes like DPLR or LAURA, and that lines of sight have been constructed and written out in the format required by NEQAIR v14.0. There are two principal modes for running NEQAIR v14.0. In the first mode NEQAIR v14.0 is used as a tool for creating synthetic spectra of any desired resolution (including convolution with a specified instrument/slit function). The first mode is typically exercised in simulating/interpreting spectroscopic measurements of different sources (e.g. shock tube data, plasma torches, etc.). In the second mode, NEQAIR v14.0 is used as a radiative heat flux prediction tool for flight projects. Correspondingly, NEQAIR has

  2. System and method for radiation dose calculation within sub-volumes of a monte carlo based particle transport grid

    DOEpatents

    Bergstrom, Paul M.; Daly, Thomas P.; Moses, Edward I.; Patterson, Jr., Ralph W.; Schach von Wittenau, Alexis E.; Garrett, Dewey N.; House, Ronald K.; Hartmann-Siantar, Christine L.; Cox, Lawrence J.; Fujino, Donald H.

    2000-01-01

    A system and method is disclosed for radiation dose calculation within sub-volumes of a particle transport grid. In a first step of the method voxel volumes enclosing a first portion of the target mass are received. A second step in the method defines dosel volumes which enclose a second portion of the target mass and overlap the first portion. A third step in the method calculates common volumes between the dosel volumes and the voxel volumes. A fourth step in the method identifies locations in the target mass of energy deposits. And, a fifth step in the method calculates radiation doses received by the target mass within the dosel volumes. A common volume calculation module inputs voxel volumes enclosing a first portion of the target mass, inputs voxel mass densities corresponding to a density of the target mass within each of the voxel volumes, defines dosel volumes which enclose a second portion of the target mass and overlap the first portion, and calculates common volumes between the dosel volumes and the voxel volumes. A dosel mass module, multiplies the common volumes by corresponding voxel mass densities to obtain incremental dosel masses, and adds the incremental dosel masses corresponding to the dosel volumes to obtain dosel masses. A radiation transport module identifies locations in the target mass of energy deposits. And, a dose calculation module, coupled to the common volume calculation module and the radiation transport module, for calculating radiation doses received by the target mass within the dosel volumes.

  3. Understanding the direct radiative effect of dust aerosols on transport pathways using the NASA GEOS-5 AGCM

    NASA Astrophysics Data System (ADS)

    Nowottnick, E. P.; Colarco, P. R.; Lau, W. K.; Kim, K.

    2012-12-01

    African dust aerosols are transported across the Atlantic Ocean to the Caribbean by the easterly trade winds.While in transport, dust aerosols interact with the Earth system in various ways, ranging from influencing the local radiation balance to serving as a nutrient for tropical ecosystems.However, our current understanding of these processes is incomplete and serves as a source of uncertainty in Earth system modeling.Here, we focus on understanding the direct radiative impacts of African dust aerosols on the atmosphere using the NASA GEOS-5 atmospheric general circulation model that simulates aerosols with an online version of the GOCART model. For this study, we compare a high resolution GEOS-5 climate simulation where aerosols have been radiatively coupled to the atmosphere to one where aerosols are treated as passive tracers for June - September, 2009. Utilizing streamfunction and velocity potentials of the simulated dust mass flux, we isolate differences in dust transport pathways caused by the direct radiative effect of dust by comparing the rotational and divergent components of the dust flow in the horizontal and vertical on various timescales.Additionally, we pay special attention to the influence of dust aerosols on African Easterly Jet (AEJ) position and strength, as well as temperature profiles, cloudiness, and precipitation to gain further insight into the direct radiative effect of dust aerosols on the atmosphere

  4. Radiation transport analyses in support of the SNS Target Station Neutron Beam Line Shutters Title I Design

    SciTech Connect

    Miller, T.M.; Pevey, R.E.; Lillie, R.A.; Johnson, J.O.

    2000-12-01

    A detailed radiation transport analysis of the Spallation Neutron Source (SNS) shutters is important for the construction of the SNS because of its impact on conventional facility design, normal operation of the facility, and maintenance operations. Thus far the analysis of the SNS shutter travel gaps has been completed. This analysis was performed using coupled Monte Carlo and multi-dimensional discrete ordinates calculations.

  5. Radiation transport codes for potential applications related to radiobiology and radiotherapy using protons, neutrons, and negatively charged pions

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.

    1972-01-01

    Several Monte Carlo radiation transport computer codes are used to predict quantities of interest in the fields of radiotherapy and radiobiology. The calculational methods are described and comparisions of calculated and experimental results are presented for dose distributions produced by protons, neutrons, and negatively charged pions. Comparisons of calculated and experimental cell survival probabilities are also presented.

  6. Accurate dose assessment system for an exposed person utilising radiation transport calculation codes in emergency response to a radiological accident.

    PubMed

    Takahashi, F; Shigemori, Y; Seki, A

    2009-01-01

    A system has been developed to assess radiation dose distribution inside the body of exposed persons in a radiological accident by utilising radiation transport calculation codes-MCNP and MCNPX. The system consists mainly of two parts, pre-processor and post-processor of the radiation transport calculation. Programs for the pre-processor are used to set up a 'problem-dependent' input file, which defines the accident condition and dosimetric quantities to be estimated. The program developed for the post-processor part can effectively indicate dose information based upon the output file of the code. All of the programs in the dosimetry system can be executed with a generally used personal computer and accurately give the dose profile to an exposed person in a radiological accident without complicated procedures. An experiment using a physical phantom was carried out to verify the availability of the dosimetry system with the developed programs in a gamma ray irradiation field.

  7. Thin film AlSb carrier transport properties and room temperature radiation response

    NASA Astrophysics Data System (ADS)

    Vaughan, Erin Ivey

    Theoretical predictions for AlSb material properties have not been realized using bulk growth methods. This research was motivated by advances in molecular beam epitaxial (MBE) growth technology to produce high-quality thin-film AlSb for the purpose of evaluating transport properties and suitability for radiation detection. Simulations using MCNP5 were performed to benchmark an existing silicon surface barrier detector and to predict ideal AlSb detector behavior, with the finding that AlSb should have improved detection efficiency due to the larger atomic number of Sb compared with Si. GaSb diodes were fabricated by both homoepitaxial MBE and ion implantation methods in order to determine the effect on the radiation detection performance. It was found that the radiation response for the MBE grown GaSb diodes was very uniform, whereas the ion-implanted GaSb diodes exhibited highly variable spectral behavior. Two sets of AlSb heterostructures were fabricated by MBE methods; one for a Hall doping study and the other for a radiation response study. The samples were characterized for material quality using transmission electron microscopy (TEM), Nomarski imaging, atomic force microscopy (AFM), x-ray diffraction (XRD), I-V curve analysis, and Hall effect measurements. The Hall study samples were grown on semi-insulating (SI) GaAs substrates and contained a thin GaAs layer on top to protect the AlSb from oxygen. Doping for the AlSb layer was achieved using GaTe and Be for n- and p-type conductivity, respectively, with intended doping densities ranging from 1015 to 1017 cm -3. Results for net carrier concentration ranged 2x10 9 to 1x1017 cm-3, 60 to 3000 cm 2/Vs for mobility, and 2 to 106 Ω-cm for resistivity, with the undoped AlSb samples presenting the best values. The radiation detector samples were designed to be PIN diodes, with undoped AlSb sandwiched between n-type GaAs substrate and p-type GaSb as a conductive oxygen-protective layer. Energy spectra were measured

  8. Los Alamos National Laboratory Waste Management Program

    SciTech Connect

    Lopez-Escobedo, G.M.; Hargis, K.M.; Douglass, C.R.

    2007-07-01

    Los Alamos National Laboratory's (LANL) waste management program is responsible for disposition of waste generated by many of the LANL programs and operations. LANL generates liquid and solid waste that can include radioactive, hazardous, and other constituents. Where practical, LANL hazardous and mixed wastes are disposed through commercial vendors; low-level radioactive waste (LLW) and radioactive asbestos-contaminated waste are disposed on site at LANL's Area G disposal cells, transuranic (TRU) waste is disposed at the Waste Isolation Pilot Plant (WIPP), and high-activity mixed wastes are disposed at the Nevada Test Site (NTS) after treatment by commercial vendors. An on-site radioactive liquid waste treatment facility (RLWTF) removes the radioactive constituents from liquid wastes and treated water is released through an NPDES permitted outfall. LANL has a very successful waste minimization program. Routine hazardous waste generation has been reduced over 90% since 1993. LANL has a DOE Order 450.1-compliant environmental management system (EMS) that is ISO 14001 certified; waste minimization is integral to setting annual EMS improvement objectives. Looking forward, under the new LANL management and operating contractor, Los Alamos National Security (LANS) LLC, a Zero Liquid Discharge initiative is being planned that should eliminate flow to the RLWTF NPDES-permitted outfall. The new contractor is also taking action to reduce the number of permitted waste storage areas, to charge generating programs directly for the cost to disposition waste, and to simplify/streamline the waste system. (authors)

  9. Modern Monte Carlo particle transport simulation for safety and radiation protection applications in accelerometer technology and in space science

    NASA Astrophysics Data System (ADS)

    Filges, Detlef

    1992-04-01

    The application potential of modern particle radiation transport simulations to solve safety and radiation protection problems in accelerator technology and in space science and technology is presented. It is shown to what extent Monte Carlo simulation is helpful in defining safety regulations, safety standards and in determining corresponding safety proofs. For this purpose the basic methods are described and their performance together with particular examples are assessed. The state of the art of the computational methods is described together with the existing computer codes. The details of the current three dimensional geometry packages are also given. Necessary nuclear transport data and reaction cross sections in respect to shielding and safety protection problems are investigated. The performance and flexibility of HERMES (High Energy Radiation Monte Carlo Elaborate System), and its utilization in solving safety protection problems are demonstrated. Examples of radiation protection and high energy source shielding for medium and high energy particle accelerators and for high current particle accelerator target systems are summarized. Radiation protection and shielding of space vehicles against cosmic ray radiation are compiled and assessed. Validations of experimental results are also given.

  10. Comparison of Radiative Forcing Calculations Due to Mineral Dust from a Transport Model, Satellite Measurements and an Assimilation System

    NASA Technical Reports Server (NTRS)

    Weaver, Clark J.; Ginoux, Paul; Hsu, Christina; Joiner, Joanna; Chou, Ming-Dah

    1999-01-01

    This study uses information on mineral aerosol from a transport model to calculate global radiative forcing values. The transport model is driven by assimilated meteorology and outputs three-dimensional dust spatial information for various size ranges. The dust fields are input to an off-line radiative transfer calculation to obtain the direct radiative forcing due to the dust fields. During June, July and August of 1988 presence of dust 1) reduces the global net incoming radiation at the top of atmosphere (TOA) by 0.3 to 0.7 W/sq m and 2) reduces net incoming radiation at the earth's surface by 1.3 to 2.0 W/sq m. Over Africa our estimates of the reduction of radiation at the top of atmosphere compare well with TOA reductions derived from ERBE and TOMS satellite data. However, our heating rates are not consistent with analysis temperature increments produced by the assimilation system over regions of high aerosol loading. These increments are based on differences between temperature observations and temperatures from the assimilation general circulation model. One explanation is that the lower tropospheric temperatures retrieved by TOVS are being contaminated by mineral aerosol.

  11. Distribution Iteration: A Robust Alternative to Source Iteration for Solving the Discrete Ordinates Radiation Transport Equations in Slab and XY - Geometries

    DTIC Science & Technology

    2008-09-15

    differential equation that is coupled in space and angle. The discrete ordinates method discretizes the BTE in space and angle and the resulting...RADIATION TRANSPORT EQUATIONS IN SLAB AND XY - GEOMETRIES DISSERTATION Nicholas J. Prins, Lieutenant Colonel, USA AFIT/DS/ENP/08-S04...SOLVING THE DISCRETE ORDINATES RADIATION TRANSPORT EQUATIONS IN SLAB AND XY - GEOMETRIES DISSERTATION Presented to the Faculty Graduate

  12. DOE Los Alamos National Laboratory – PV Feasibility Assessment, 2015 Update, NREL Final Report

    SciTech Connect

    Dean, Jesse; Witt, Monica Rene

    2016-04-06

    This report summarizes solar and wind potential for Los Alamos National Laboratory (LANL). This report is part of the “Los Alamos National Laboratory and Los Alamos County Renewable Generation” study.

  13. Massively parallel simulation with DOE's ASCI supercomputers : an overview of the Los Alamos Crestone project

    SciTech Connect

    Weaver, R. P.; Gittings, M. L.

    2004-01-01

    The Los Alamos Crestone Project is part of the Department of Energy's (DOE) Accelerated Strategic Computing Initiative, or ASCI Program. The main goal of this software development project is to investigate the use of continuous adaptive mesh refinement (CAMR) techniques for application to problems of interest to the Laboratory. There are many code development efforts in the Crestone Project, both unclassified and classified codes. In this overview I will discuss the unclassified SAGE and the RAGE codes. The SAGE (SAIC adaptive grid Eulerian) code is a one-, two-, and three-dimensional multimaterial Eulerian massively parallel hydrodynamics code for use in solving a variety of high-deformation flow problems. The RAGE CAMR code is built from the SAGE code by adding various radiation packages, improved setup utilities and graphics packages and is used for problems in which radiation transport of energy is important. The goal of these massively-parallel versions of the codes is to run extremely large problems in a reasonable amount of calendar time. Our target is scalable performance to {approx}10,000 processors on a 1 billion CAMR computational cell problem that requires hundreds of variables per cell, multiple physics packages (e.g. radiation and hydrodynamics), and implicit matrix solves for each cycle. A general description of the RAGE code has been published in [l],[ 2], [3] and [4]. Currently, the largest simulations we do are three-dimensional, using around 500 million computation cells and running for literally months of calendar time using {approx}2000 processors. Current ASCI platforms range from several 3-teraOPS supercomputers to one 12-teraOPS machine at Lawrence Livermore National Laboratory, the White machine, and one 20-teraOPS machine installed at Los Alamos, the Q machine. Each machine is a system comprised of many component parts that must perform in unity for the successful run of these simulations. Key features of any massively parallel system

  14. Beam transport radiation shielding for branch lines 2-ID-B and 2-ID-C

    SciTech Connect

    Feng, Y.P.; Lai, B.; McNulty, I.; Dejus, R.J.; Randall, K.J.; Yun, W.

    1995-08-01

    The x-ray radiation shielding requirements beyond the first optics enclosure have been considered for the beam transport of the 2-ID-B and 2-ID-C branch lines of Sector 2 (SRI-CAT) of the APS. The first three optical components (mirrors) of the 2-ID-B branch are contained within the shielded first optics enclosure. Calculations indicate that scattering of the primary synchrotron beam by beamline components outside the enclosure, such as apertures and monochromators, or by gas particles in case of vacuum failure is within safe limits for this branch. A standard 2.5-inch-diameter stainless steel pipe with 1/16-inch-thick walls provides adequate shielding to reduce the radiation dose equivalent rate to human tissue to below the maximum permissible limit of 0.25 mrem/hr. The 2-ID-C branch requires, between the first optics enclosure where only two mirrors are used and the housing for the third mirror, additional lead shielding (0.75 mm) and a minimum approach distance of 2.6 cm. A direct beam stop consisting of at least 4.5 mm of lead is also required immediately downstream of the third mirror for 2-ID-C. Finally, to stop the direct beam from escaping the experimental station, a beam stop consisting of at least 4-mm or 2.5-mm steel is required for the 2-ID-B or 2-ID-C branches, respectively. This final requirement can be met by the vacuum chambers used to house the experiments for both branch lines.

  15. Radiation Transport Analysis in Chalcogenide-Based Devices and a Neutron Howitzer Using MCNP

    NASA Astrophysics Data System (ADS)

    Bowler, Herbert

    As photons, electrons, and neutrons traverse a medium, they impart their energy in ways that are analytically difficult to describe. Monte Carlo methods provide valuable insight into understanding this behavior, especially when the radiation source or environment is too complex to simplify. This research investigates simulating various radiation sources using the Monte Carlo N-Particle (MCNP) transport code, characterizing their impact on various materials, and comparing the simulation results to general theory and measurements. A total of five sources were of interest: two photon sources of different incident particle energies (3.83 eV and 1.25 MeV), two electron sources also of different energies (30 keV and 100 keV), and a californium-252 (Cf-252) spontaneous fission neutron source. Lateral and vertical programmable metallization cells (PMCs) were developed by other researchers for exposure to these photon and electron sources, so simplified PMC models were implemented in MCNP to estimate the doses and fluences. Dose rates measured around the neutron source and the predicted maximum activity of activation foils exposed to the neutrons were determined using MCNP and compared to experimental results obtained from gamma-ray spectroscopy. The analytical fluence calculations for the photon and electron cases agreed with MCNP results, and differences are due to MCNP considering particle movements that hand calculations do not. Doses for the photon cases agreed between the analytical and simulated results, while the electron cases differed by a factor of up to 4.8. Physical dose rate measurements taken from the neutron source agreed with MCNP within the 10% tolerance of the measurement device. The activity results had a percent error of up to 50%, which suggests a need to further evaluate the spectroscopy setup.

  16. Los Alamos personnel and area criticality dosimeter systems

    SciTech Connect

    Vasilik, D.G.; Martin, R.W.

    1981-06-01

    Fissionable materials are handled and processed at the Los Alamos National Laboratory. Although the probability of a nuclear criticality accident is very remote, it must be considered. Los Alamos maintains a broad spectrum of dose assessment capabilities. This report describes the methods employed for personnel neutron, area neutron, and photon dose evaluations with passive dosimetry systems.

  17. The Climate at Los Alamos; Are we measurement changes?

    SciTech Connect

    Dewart, Jean Marie

    2015-04-16

    A new report shows new graphic displays of the weather trends in Los Alamos, New Mexico, and at the Los Alamos National Laboratory (LANL). The graphs show trends of average, minimum average, and maximum average temperature for summer and winter months going back decades. Records of summer and winter precipitation are also included in the report.

  18. Audit of personal property management at Los Alamos National Laboratory

    SciTech Connect

    Not Available

    1993-12-07

    The Department of Energy`s (Department) Albuquerque Operations Office (Albuquerque) and the Los Alamos National Laboratory (Los Alamos) are responsible for ensuring that Los Alamos maintains an efficient and effective personal property management system that protects, identifies, and controls Government-owned personal property in accordance with applicable regulations. Albuquerque is responsible for reviewing and approving Los Alamos` personal property management system. Los Alamos is responsible for ensuring that personal property is properly protected, identified, and controlled. The audit disclosed that Los Alamos did not have an efficient and effective personal property management system to ensure that personal property was adequately protected, identified, and controlled. In addition, Albuquerque did not approve or disapprove Los Alamos` personal property management system consistent with Federal and Department regulations. Specifically, the audit showed that Los Alamos did not account for $11.6 million of personal property. In addition, $22.2 million of personal property was not properly recorded in the database, $61.7 million of personal property could not be inventoried, and loans to employees and other entities were not adequately justified. As a result, from a total personal property inventory of approximately $1 billion, it is estimated that $100 million of personal property may not be accounted for, and $207 million may not be correctly recorded in the database. Moreover, substantial amounts of personal property on loan to employees and other entities were at risk of unauthorized use. Albuquerque concurred with the finding and agreed to implement the corrective actions recommended in the report.

  19. Evidence for dust-driven, radial plasma transport in Saturn's inner radiation belts

    NASA Astrophysics Data System (ADS)

    Roussos, E.; Krupp, N.; Kollmann, P.; Paranicas, C.; Mitchell, D. G.; Krimigis, S. M.; Andriopoulou, M.

    2016-08-01

    A survey of Cassini MIMI/LEMMS data acquired between 2004 and 2015 has led to the identification of 13 energetic electron microsignatures that can be attributed to particle losses on one of the several faint rings of the planet. Most of the signatures were detected near L-shells that map between the orbits of Mimas and Enceladus or near the G-ring. Our analysis indicates that it is very unlikely for these signatures to have originated from absorption on Mimas, Enceladus or unidentified Moons and rings, even though most were not found exactly at the L-shells of the known rings of the saturnian system (G-ring, Methone, Anthe, Pallene). The lack of additional absorbers is apparent in the L-shell distribution of MeV ions which are very sensitive for tracing the location of weakly absorbing material permanently present in Saturn's radiation belts. This sensitivity is demonstrated by the identification, for the first time, of the proton absorption signatures from the asteroid-sized Moons Pallene, Anthe and/or their rings. For this reason, we investigate the possibility that the 13 energetic electron events formed at known saturnian rings and the resulting depletions were later displaced radially by one or more magnetospheric processes. Our calculations indicate that the displacement magnitude for several of those signatures is much larger than the one that can be attributed to radial flows imposed by the recently discovered noon-to-midnight electric field in Saturn's inner magnetosphere. This observation is consistent with a mechanism where radial plasma velocities are enhanced near dusty obstacles. Several possibilities are discussed that may explain this observation, including a dust-driven magnetospheric interchange instability, mass loading by the pick-up of nanometer charged dust grains and global magnetospheric electric fields induced by perturbed orbits of charged dust due to the act of solar radiation pressure. Indirect evidence for a global scale interaction

  20. Stormtime ring current and radiation belt ion transport: Simulations and interpretations

    NASA Technical Reports Server (NTRS)

    Lyons, Larry R.; Gorney, David J.; Chen, Margaret W.; Schulz, Michael

    1995-01-01

    We use a dynamical guiding-center model to investigate the stormtime transport of ring current and radiation-belt ions. We trace the motion of representative ions' guiding centers in response to model substorm-associated impulses in the convection electric field for a range of ion energies. Our simple magnetospheric model allows us to compare our numerical results quantitatively with analytical descriptions of particle transport, (e.g., with the quasilinear theory of radial diffusion). We find that 10-145-keV ions gain access to L approximately 3, where they can form the stormtime ring current, mainly from outside the (trapping) region in which particles execute closed drift paths. Conversely, the transport of higher-energy ions (approximately greater than 145 keV at L approximately 3) turns out to resemble radial diffusion. The quasilinear diffusion coefficient calculated for our model storm does not vary smoothly with particle energy, since our impulses occur at specific (although randomly determined) times. Despite the spectral irregularity, quasilinear theory provides a surprisingly accurate description of the transport process for approximately greater than 145-keV ions, even for the case of an individual storm. For 4 different realizations of our model storm, the geometric mean discrepancies between diffusion coefficients D(sup sim, sub LL) obtained from the simulations and the quasilinear diffusion coefficient D(sup ql, sub LL) amount to factors of 2.3, 2.3, 1.5, and 3.0, respectively. We have found that these discrepancies between D(sup sim, sub LL) and D(sup ql, sub LL) can be reduced slightly by invoking drift-resonance broadening to smooth out the sharp minima and maxima in D(sup ql, sub LL). The mean of the remaining discrepancies between D(sup sim, sub LL) and D(sup ql, sub LL) for the 4 different storms then amount to factors of 1.9, 2.1, 1.5, and 2.7, respectively. We find even better agreement when we reduce the impulse amplitudes systematically in

  1. Studies of Particle Acceleration, Transport and Radiation in Impulsive Phase of Solar Flares

    NASA Technical Reports Server (NTRS)

    Petrosian, Vahe

    2005-01-01

    the reconnection region above a flare loop. This turbulence accelerates particles stochastically which radiate some of their energy in this region but carry most of their energy to the footpoints of the loop, where they lose all their energy and radiate bulk of the observed radiation as in the traditional thick target model. In the past we have worked on various aspects of this model. We have evaluated the interaction rates of the plasma waves with electrons and ions, developed theoretical frameworks for the acceleration, transport and radiative processes, and produced numerical codes for the investigation of these processes. The goal of this grant has been further development and testing of this new paradigm, with emphases on the relative acceleration of electrons and ions and on a comprehensive investigation of the turbulence generation, cascade, and damping processes. We review several pieces of important evidence that we have uncovered indicating the crucial roles of turbulence, in and we describe accomplishments during the past two years of this grant.

  2. Comparison of Integrated Radiation Transport Models with TEPC Measurements for the Average Quality Factors in Spaceflights

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Nikjoo, Hooshang; Dicello, John F.; Pisacane, Vincent; Cucinotta, Francis A.

    2007-01-01

    radiation type (Z = 1 to 28). Because the anomalous response has been observed at large event sizes in the experiment due to the escape of energy out of sensitive volume by delta-rays and the entry of delta-rays from the high-density wall into the low-density gas-volume cavity, Monte Carlo simulation was also made for the response of a walled-TEPC with wall thickness 2 mm and density 1 g/cm(exp 3). The radius of cavity was set to 6.35 mm and a gas density 7.874 x 10(exp -5) g/cm(exp 3). The response of the walled- and the wall-less counters were compared. The average quality factor Q(sub ave)(y) for trapped protons on STS-89 demonstrated the good agreement between the model calculations and flight TEPC data as shown. Using an integrated space radiation model (this includes the transport codes HZETRN and BRYNTRN, the quantum nuclear interaction model QMSFRG) and the resultant response distribution functions of walled-TEPC from Monte-Carlo track simulations, we compared model calculations with walled-TEPC measurements from NASA missions in LEO and made predictions for the lunar and the Mars missions. The Q(sub ave)(y) values for the trapped or the solar protons ranged from 1.9-2.5. This over-estimates the Qave(LET) values which ranged from 1.4-1.6. Both quantities increase with shield thickness due to nuclear fragmentation. The Q(sub ave)(LET) for the complete GCR spectra was found to be 3.5-4.5, while flight TEPCs measured 2.9-3.4 for Q(sub ave)(y). The GCR values are decreasing with the shield thickness. Our analysis for a proper interpretation of data supports the use of TEPCs for monitoring space radiation environment.

  3. Radiative transport in plant canopies: Forward and inverse problem for UAV applications

    NASA Astrophysics Data System (ADS)

    Furfaro, Roberto

    This dissertation deals with modeling the radiative regime in vegetation canopies and the possible remote sensing applications derived by solving the forward and inverse canopy transport equation. The aim of the research is to develop a methodology (called "end-to-end problem solution") that, starting from first principles describing the interaction between light and vegetation, constructs, as the final product, a tool that analyzes remote sensing data for precision agriculture (ripeness prediction). The procedure begins by defining the equations that describe the transport of photons inside the leaf and within the canopy. The resulting integro-differential equations are numerically integrated by adapting the conventional discrete-ordinate methods to compute the reflectance at the top of the canopy. The canopy transport equation is also analyzed to explore its spectral properties. The goal here is to apply Case's method to determine eigenvalues and eigenfunctions and to prove completeness. A model inversion is attempted by using neural network algorithms. Using input-outputs generated by running the forward model, a neural network is trained to learn the inverse map. The model-based neural network represents the end product of the overall procedure. During Oct 2002, an Unmanned Aerial Vehicles (UAVs) equipped with a camera system, flew over Kauai to take images of coffee field plantations. Our goal is to predict the amount of ripe coffee cherries for optimal harvesting. The Leaf-Canopy model was modified to include cherries as absorbing and scattering elements and two classes of neural networks were trained on the model to learn the relationship between reflectance and percentage of ripe, over-ripe and under-ripe cherries. The neural networks are interfaced with images coming from Kauai to predict ripeness percentage. Both ground and airborne images are considered. The latter were taken from the on-board Helios UAV camera system flying over the Kauai coffee field

  4. Radiative Transport Modeling of High Frequency Regional Seismograms for Event Discrimination

    NASA Astrophysics Data System (ADS)

    Cormier, V. F.; Sanborn, C. J.; Walsh, S.; Fitzpatrick, M.

    2015-12-01

    The differences between earthquakes and explosions are largest in the highest recordable frequency band. In this band, scattering of elastic energy by small-scale heterogeneity (less than a wavelength) can equilibrate energy on components of motion and stabilize the behavior of the Lg wave trapped in Earth's crust. Larger-scale deterministic structure (greater than a wavelength) still assumes major control over the efficiency or blockage of the Lg and the efficiency of other regional phases. We model high frequency regional seismic wave codas (2-4 Hz) for the combined effects of the large-scale 3-D (deterministic) and the small scale (statistical) structure with a radiative transport algorithm. The algorithm propagates packets of body wave energy with ray theory a through a large-scale deterministic 3-D structure, and includes the effects of multiple scattering by small-scale statistical structure. Coda envelopes are synthesized to illustrate sensitivities to variations in the parameters describing small-scale statistical heterogeneity, intrinsic attenuation, Lg blockage due to large-scale variations in crustal thickness, and the effects of tectonic release estimated from the seismograms of nuclear tests. We predict that event discriminants based on P/Lg amplitude ratios will best separate earthquake and explosion populations at frequencies 2 Hz and higher.

  5. An Improved Elastic and Nonelastic Neutron Transport Algorithm for Space Radiation

    NASA Technical Reports Server (NTRS)

    Clowdsley, Martha S.; Wilson, John W.; Heinbockel, John H.; Tripathi, R. K.; Singleterry, Robert C., Jr.; Shinn, Judy L.

    2000-01-01

    A neutron transport algorithm including both elastic and nonelastic particle interaction processes for use in space radiation protection for arbitrary shield material is developed. The algorithm is based upon a multiple energy grouping and analysis of the straight-ahead Boltzmann equation by using a mean value theorem for integrals. The algorithm is then coupled to the Langley HZETRN code through a bidirectional neutron evaporation source term. Evaluation of the neutron fluence generated by the solar particle event of February 23, 1956, for an aluminum water shield-target configuration is then compared with MCNPX and LAHET Monte Carlo calculations for the same shield-target configuration. With the Monte Carlo calculation as a benchmark, the algorithm developed in this paper showed a great improvement in results over the unmodified HZETRN solution. In addition, a high-energy bidirectional neutron source based on a formula by Ranft showed even further improvement of the fluence results over previous results near the front of the water target where diffusion out the front surface is important. Effects of improved interaction cross sections are modest compared with the addition of the high-energy bidirectional source terms.

  6. Fast transport in phase space due to nonlinear wave-particle interaction in the radiation belts.

    NASA Astrophysics Data System (ADS)

    Artemyev, Anton; Vasiliev, Alexii; Mourenas, Didier; Agapitov, Oleksiy; Krasnoselskikh, Vladimir; Boscher, Daniel; Rolland, Guy

    2014-05-01

    We present an analytical, simplified formulation accounting for the fast transport of particles in phase space, in the presence of nonlinear wave-particle resonant interactions in an inhomogeneous magnetic field representative of the radiation belts. We show that the general approach for the description of the evolution of the particle velocity distribution based on the Fokker-Plank equation can be modified to consider the process of nonlinear wave-particle interaction, including particle trapping. Such a modification consists in one additional operator describing fast particle jumps in phase space. The proposed approach is illustrated by considering the acceleration of relativistic electrons by strongly oblique whistler waves. We determine the typical variation of electron phase-density due to nonlinear wave-particle interaction and compare this variation with pitch-angle/energy diffusion due to quasi-linear electron scattering. We show that relation between nonlinear and quasi-linear effects is controlled by the distribution of wave-amplitudes. When this distribution has a heavy tail, nonlinear effects can become dominant in the formation of the electron energy distribution.

  7. Integrated Radiation Transport and Thermo-Mechanics Simulation of a PWR Assembly

    SciTech Connect

    Clarno, Kevin T; Hamilton, Steven P; Philip, Bobby; Sampath, Rahul S; Allu, Srikanth; Berrill, Mark A; Barai, Pallab; Banfield, James E

    2012-01-01

    The Advanced Multi-Physics (AMP) Nuclear Fuel Performance code (AMPFuel) is focused on predicting the temperature and strain within a nuclear fuel assembly to evaluate the performance and safety of existing and advanced nuclear fuel bundles within existing and advanced nuclear reactors. AMPFuel was extended to include an integrated nuclear fuel assembly capability for (one-way) coupled radiation transport and nuclear fuel assembly thermo-mechanics. This capability is the initial step towards incorporating an improved predictive nuclear fuel assembly modeling capability to accurately account for source terms, such as the neutron flux distribution, coolant conditions, and assembly mechanical stresses, of traditional (single-pin) nuclear fuel performance simulation. AMPFuel was used to model an entire 17 x 17 Pressurized Water Reactor (PWR) fuel assembly with many of the features resolved in three dimensions (for thermo-mechanics and/or neutronics), including the fuel, gap, and cladding of each of the 264 fuel pins, the 25 guide tubes, top and bottom structural regions, and the upper and lower (neutron) reflector regions. The final full-assembly calculation was executed on Jaguar (Cray XT5) at the Oak Ridge Leadership Computing Facility using 40,000 cores in under 10 hours to model over 162 billion degrees of freedom for 10 loading steps.

  8. A space–angle DGFEM approach for the Boltzmann radiation transport equation with local angular refinement

    SciTech Connect

    Kópházi, József Lathouwers, Danny

    2015-09-15

    In this paper a new method for the discretization of the radiation transport equation is presented, based on a discontinuous Galerkin method in space and angle that allows for local refinement in angle where any spatial element can support its own angular discretization. To cope with the discontinuous spatial nature of the solution, a generalized Riemann procedure is required to distinguish between incoming and outgoing contributions of the numerical fluxes. A new consistent framework is introduced that is based on the solution of a generalized eigenvalue problem. The resulting numerical fluxes for the various possible cases where neighboring elements have an equal, higher or lower level of refinement in angle are derived based on tensor algebra and the resulting expressions have a very clear physical interpretation. The choice of discontinuous trial functions not only has the advantage of easing local refinement, it also facilitates the use of efficient sweep-based solvers due to decoupling of unknowns on a large scale thereby approaching the efficiency of discrete ordinates methods with local angular resolution. The approach is illustrated by a series of numerical experiments. Results show high orders of convergence for the scalar flux on angular refinement. The generalized Riemann upwinding procedure leads to stable and consistent solutions. Further the sweep-based solver performs well when used as a preconditioner for a Krylov method.

  9. Generalized reference fields and source interpolation for the difference formulation of radiation transport

    NASA Astrophysics Data System (ADS)

    Luu, Thomas; Brooks, Eugene D.; Szőke, Abraham

    2010-03-01

    In the difference formulation for the transport of thermally emitted photons the photon intensity is defined relative to a reference field, the black body at the local material temperature. This choice of reference field combines the separate emission and absorption terms that nearly cancel, thereby removing the dominant cause of noise in the Monte Carlo solution of thick systems, but introduces time and space derivative source terms that cannot be determined until the end of the time step. The space derivative source term can also lead to noise induced crashes under certain conditions where the real physical photon intensity differs strongly from a black body at the local material temperature. In this paper, we consider a difference formulation relative to the material temperature at the beginning of the time step, or in cases where an alternative temperature better describes the radiation field, that temperature. The result is a method where iterative solution of the material energy equation is efficient and noise induced crashes are avoided. We couple our generalized reference field scheme with an ad hoc interpolation of the space derivative source, resulting in an algorithm that produces the correct flux between zones as the physical system approaches the thick limit.

  10. NEQAIR96,Nonequilibrium and Equilibrium Radiative Transport and Spectra Program: User's Manual

    NASA Technical Reports Server (NTRS)

    Whiting, Ellis E.; Park, Chul; Liu, Yen; Arnold, James O.; Paterson, John A.

    1996-01-01

    This document is the User's Manual for a new version of the NEQAIR computer program, NEQAIR96. The program is a line-by-line and a line-of-sight code. It calculates the emission and absorption spectra for atomic and diatomic molecules and the transport of radiation through a nonuniform gas mixture to a surface. The program has been rewritten to make it easy to use, run faster, and include many run-time options that tailor a calculation to the user's requirements. The accuracy and capability have also been improved by including the rotational Hamiltonian matrix formalism for calculating rotational energy levels and Hoenl-London factors for dipole and spin-allowed singlet, doublet, triplet, and quartet transitions. Three sample cases are also included to help the user become familiar with the steps taken to produce a spectrum. A new user interface is included that uses check location, to select run-time options and to enter selected run data, making NEQAIR96 easier to use than the older versions of the code. The ease of its use and the speed of its algorithms make NEQAIR96 a valuable educational code as well as a practical spectroscopic prediction and diagnostic code.

  11. Radiative transport produced by oblique illumination of turbid media with collimated beams.

    PubMed

    Gardner, Adam R; Kim, Arnold D; Venugopalan, Vasan

    2013-06-01

    We examine the general problem of light transport initiated by oblique illumination of a turbid medium with a collimated beam. This situation has direct relevance to the analysis of cloudy atmospheres, terrestrial surfaces, soft condensed matter, and biological tissues. We introduce a solution approach to the equation of radiative transfer that governs this problem, and develop a comprehensive spherical harmonics expansion method utilizing Fourier decomposition (SHEF(N)). The SHEF(N) approach enables the solution of problems lacking azimuthal symmetry and provides both the spatial and directional dependence of the radiance. We also introduce the method of sequential-order smoothing that enables the calculation of accurate solutions from the results of two sequential low-order approximations. We apply the SHEF(N) approach to determine the spatial and angular dependence of both internal and boundary radiances from strongly and weakly scattering turbid media. These solutions are validated using more costly Monte Carlo simulations and reveal important insights regarding the evolution of the radiant field generated by oblique collimated beams spanning ballistic and diffusely scattering regimes.

  12. Review of modeling of losses and sources of relativistic electrons in the outer radiation belt I: Radial transport

    NASA Astrophysics Data System (ADS)

    Shprits, Yuri Y.; Elkington, Scot R.; Meredith, Nigel P.; Subbotin, Dmitriy A.

    2008-11-01

    In this paper, we focus on the modeling of radial transport in the Earth's outer radiation belt. A historical overview of the first observations of the radiation belts is presented, followed by a brief description of radial diffusion. We describe how resonant interactions with poloidal and toroidal components of the ULF waves can change the electron's energy and provide radial displacements. We also present radial diffusion and guiding center simulations that show the importance of radial transport in redistributing relativistic electron fluxes and also in accelerating and decelerating radiation belt electrons. We conclude by presenting guiding center simulations of the coupled particle tracing and magnetohydrodynamic (MHD) codes and by discussing the origin of relativistic electrons at geosynchronous orbit. Local acceleration and losses and 3D simulations of the dynamics of the radiation belt fluxes are discussed in the companion paper [Shprits, Y.Y., Subbotin, D.A., Meredith, N.P., Elkington, S.R., 2008. Review of modeling of losses and sources of relativistic electrons in the outer radiation belt II: Local acceleration and loss. Journal of Atmospheric and Solar-Terrestrial Physics, this issue. doi:10.1016/j.jastp.2008.06.014].

  13. Final report on the radiological surveys of designated DX firing sites at Los Alamos National Laboratory

    SciTech Connect

    1996-09-09

    CHEMRAD was contracted by Los Alamos National Laboratory to perform USRADS{reg_sign} (UltraSonic Ranging And Data System) radiation scanning surveys at designated DX Sites at the Los Alamos National Laboratory. The primary purpose of these scanning surveys was to identify the presence of Depleted Uranium (D-38) resulting from activities at the DX Firing Sites. This effort was conducted to update the most recent surveys of these areas. This current effort was initiated with site orientation on August 12, 1996. Surveys were completed in the field on September 4, 1996. This Executive Summary briefly presents the major findings of this work. The detail survey results are presented in the balance of this report and are organized by Technical Area and Site number in section 2. This organization is not in chronological order. USRADS and the related survey methods are described in section 3. Quality Control issues are addressed in section 4. Surveys were conducted with an array of radiation detectors either mounted on a backpack frame for man-carried use (Manual mode) or on a tricycle cart (RadCart mode). The array included radiation detectors for gamma and beta surface near surface contamination as well as dose rate at 1 meter above grade. The radiation detectors were interfaced directly to an USRADS 2100 Data Pack.

  14. Los Alamos National Laboratory transuranic database analysis

    SciTech Connect

    Christensen, D.V.; Rogers, P.S.Z.; Kosiewicz, S.T.; LeBrun, D.B.

    1997-02-01

    This paper represents an overview of analyses conducted on the TRU database maintained by the Los Alamos National Laboratory (LANL). This evaluation was conducted to support the ``TRU Waste Workoff Strategies`` document and provides an estimation of the waste volume that potentially could be certified and ready for shipment to (WIPP) in April of 1998. Criteria defined in the WIPP WAC, including container type, weight limits, plutonium fissile gram equivalents and decay heat, were used to evaluated the waste for compliance. LANL evaluated the containers by facility and by waste stream to determining the most efficient plan for characterization and certification of the waste. Evaluation of the waste presently in storage suggested that 40- 60% potentially meets the WIPP WAC Rev. 5 criteria.

  15. Information about Practicums at Los Alamos

    SciTech Connect

    Bradley, Paul A.

    2012-07-24

    The Los Alamos Neutron Science Center is the premier facility for neutron science experiments ranging from cross section measurements, neutron scattering experiments, proton radiography, cold neutrons, actinide neutronic properties, and many other exciting topics. The National High Magnetic Field Laboratory is home to several powerful magnets, including the one that created the first non-destructive 100 Tesla field in March 2012. They probe the electronic structure of superconductors, magnetic properties of materials (including magneto-quantum effects). Research is also conducted in correlated materials, thermoacoustics, and magnetic properties of actinides. The Trident Laser has a unique niche with very high power, short pulse experiments, with a peak power of 10{sup 20} W in short pulse mode. Discoveries range from production of monoenergetic MeV ion beam, nonlinear kinetic plasma waves, the transition between kinetic and fluid nonlinear behavior and other laser-plasma interaction processes.

  16. Hot Dry Rock Overview at Los Alamos

    SciTech Connect

    Berger, Michael; Hendron, Robert H.

    1989-03-21

    The Hot Dry Rock (HDR) geothermal energy program is a renewable energy program that can contribute significantly to the nation's balanced and diversified energy mix. Having extracted energy from the first Fenton Hill HDR reservoir for about 400 days, and from the second reservoir for 30 days in a preliminary test, Los Alamos is focusing on the Long Term Flow Test and reservoir studies. Current budget limitations have slowed preparations thus delaying the start date of that test. The test is planned to gather data for more definitive reservoir modeling with energy availability or reservoir lifetime of primary interest. Other salient information will address geochemistry and tracer studies, microseismic response, water requirements and flow impedance which relates directly to pumping power requirements. During this year of ''preparation'' we have made progress in modeling studies, in chemically reactive tracer techniques, in improvements in acoustic or microseismic event analysis.

  17. Wintertime characteristics of aerosols over middle Indo-Gangetic Plain: Vertical profile, transport and radiative forcing

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Raju, M. P.; Singh, R. K.; Singh, A. K.; Singh, R. S.; Banerjee, T.

    2017-01-01

    Winter-specific characteristics of airborne particulates over middle Indo-Gangetic Plain (IGP) were evaluated in terms of aerosol chemical and micro-physical properties under three-dimensional domain. Emphases were made for the first time to identify intra-seasonal variations of aerosols sources, horizontal and vertical transport, effects of regional meteorology and estimating composite aerosol short-wave radiative forcing over an urban region (25°10‧-25°19‧N; 82°54‧-83°4‧E) at middle-IGP. Space-borne passive (Aqua and Terra MODIS, Aura OMI) and active sensor (CALIPSO-CALIOP) based observations were concurrently used with ground based aerosol mass measurement for entire winter and pre-summer months (December, 1, 2014 to March, 31, 2015). Exceptionally high aerosol mass loading was recorded for both PM10 (267.6 ± 107.0 μg m- 3) and PM2.5 (150.2 ± 89.4 μg m- 3) typically exceeding national standard. Aerosol type was mostly dominated by fine particulates (particulate ratio: 0.61) during pre to mid-winter episodes before being converted to mixed aerosol types (ratio: 0.41-0.53). Time series analysis of aerosols mass typically identified three dissimilar aerosol loading episodes with varying attributes, well resemble to that of previous year's observation representing its persisting nature. Black carbon (9.4 ± 3.7 μg m- 3) was found to constitute significant proportion of fine particulates (2-27%) with a strong diurnal profile. Secondary inorganic ions also accounted a fraction of particulates (PM2.5: 22.5%; PM10: 26.9%) having SO4- 2, NO3- and NH4+ constituting major proportion. Satellite retrieved MODIS-AOD (0.01-2.30) and fine mode fractions (FMF: 0.01-1.00) identified intra-seasonal variation with transport of aerosols from upper to middle-IGP through continental westerly. Varying statistical association of columnar and surface aerosol loading both in terms of fine (r; PM2.5: MODIS-AOD: 0.51) and coarse particulates (PM10: MODIS-AOD: 0.53) was

  18. Atmospheric transport in complex terrain at Los Alamos, Area G

    SciTech Connect

    Vold, E.L.

    1997-03-01

    This report documents the atmospheric dispersion used in the Area G Performance Assessment for off-site airborne dose calculations. Potential airborne contaminants from the mesa top disposal facility disperse in the complex terrain dominated by narrow mesas in parallel to narrow canyons. The dispersion is characterized by site-specific values of X/Q [(Ci/m{sup 3})/(Ci/s)] at each of two designated receptor locations, a {open_quote}maximum off-site dose{close_quote} location and a nearby population center (White Rock, NM). The values of X/Q in each of the sixteen wind sectors are first estimated with the CAP-88 computer code using 1992 annual meteorologic data from Area G and assuming an area source for release. This data captures the dominant wind direction on the mesa tops from the SSW. These dispersion parameters are assumed to apply to open, flat terrain and must be corrected for the complex mesa and canyon terrain terrain surrounding the Area G site. Additional meteorologic data has been collected over two years from six remote temporary meteorological stations operated on the mesas and in the canyons immediately around Area G. These data indicate that the wind flow in the canyons is exclusively bimodel, flowing up canyon during the day and down canyon at night. It is conservatively assumed that all ground level releases from Area G which blow out across an adjacent canyon become entrained in the canyon flow. This effectively combines the contaminant release for several sectors into a single canyon flow which is upstream during the day or downstream at night. This canyon channeling mechanism is implemented in the model by summing the wind sector dispersion factors over those sectors appropriate to the geometry for a release from Area G toward either adjacent canyon.

  19. Environmental surveillance at Los Alamos during 2008

    SciTech Connect

    Fuehne, David; Gallagher, Pat; Hjeresen, Denny; Isaacson, John; Johson, Scot; Morgan, Terry; Paulson, David; Rogers, David

    2009-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) Environmental Programs Directorate, as required by US Department of Energy Order 450.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2007. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, air; Chapters 5 and 6, water and sediments; Chapter 7, soils; and Chapter 8, foodstuffs and biota) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory’s technical areas and their associated programs, and Appendix D provides web links to more information.

  20. Environmental surveillance at Los Alamos during 2009

    SciTech Connect

    Fuehne, David; Poff, Ben; Hjeresen, Denny; Isaacson, John; Johnson, Scot; Morgan, Terry; Paulson, David; Salzman, Sonja; Rogers, David

    2010-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) environmental organization, as required by US Department of Energy Order 5400.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2009. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (air in Chapter 4; water and sediments in Chapters 5 and 6; soils in Chapter 7; and foodstuffs and biota in Chapter 8) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. The new Chapter 10 describes the Laboratory’s environmental stewardship efforts and provides an overview of the health of the Rio Grande. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory’s technical

  1. Environmental surveillance at Los Alamos during 2005

    SciTech Connect

    2006-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (LANL or the Laboratory) environmental organization, as required by US Department of Energy Order 5400.1, General Environmental Protection Program, and US Department of Energy Order 231.IA, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory's efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory's major environmental programs. Chapter 2 reports the Laboratory's compliance status for 2005. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, Air; Chapters 5 and 6, Water and Sediments; Chapter 7, Soils; and Chapter 8, Foodstuffs and Biota) in a format to meet the needs of a general and scientific audience. Chapter 9, new for this year, provides a summary of the status of environmental restoration work around LANL. A glossary and a list ofacronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory's technical areas and their associated programs, and Appendix D provides web links to more information.

  2. Factors affecting radionuclide availability to vegetables grown at Los Alamos

    SciTech Connect

    White, G.C.; Hakonson, T.E.; Ahlquist, A.J.

    1981-07-01

    A field study was conducted in 1977 on /sup 238/ /sup 239/Pu and /sup 137/Cs availability to zucchini squash (Curcurbita melopepo, hybrid seneca) and green bush beans (Phaseolus vulgaris, Landreths stringless) grown under home-garden conditions in an area at Los Alamos National Laboratory used for treated radioactive liquid waste disposal. Radionuclide concentrations were measured as a function of tissue type, height above the soil, fertilization regime, and for the squash, food-cleansing procedures. Analysis of variance procedures was used to analyze the data. Ratios of the concentration of a radionuclide in oven-dried vegetation to dry soil ranged from 0.0004 to 0.116 for the Pu isotopes, and from 0.051 to 0.255 for /sup 137/Cs. Fertilization with cattle manure reduced the Pu concentration ratios by 30% and /sup 137/Cs by 50%. Vegetative parts sampled within 20 cm of the ground surface were contaminated about four times as much as those parts growing further from the ground surface. About 65% of the contamination was removed by washing, indicating the presence of surficial contamination. The 50-year radiation dose commitment to humans consuming vegetables from the garden plot would be less than 0.05 mrem and would be due almost entirely to /sup 137/Cs.

  3. Use Of Lasers At The Los Alamos Hot Cell Facility

    NASA Astrophysics Data System (ADS)

    Lazarus, Michael E.

    1983-11-01

    An optical profilometer that uses a Techmet LaserMike scanning, focused, laser-beam, optical micrometer is installed in a remote alpha-gamma containment cell at the Los Alamos Hot-Cell Facility.1 A hot-cell extension chamber provides the nominal 30-cm (12-in.) working distance required by the LaserMike and, at the same time, keeps the LaserMike components outside the high-radiation-containment environment. This system provides measurement accu-racy better than±5 pm (0.0002 in.) on diameters between 2 and 13 mm (0.08 and 0.5 in.) at a rate of 33 measurements per second. The Hot-Cell Facility also uses a Korad 20-J-output ruby pulsed laser to drill a hole in reactor fuel element cladding to sample fission gas. The laser is then used to reweld the hole so that the fuel element will not be contaminated and may be stored without an alpha-containment barrier. The wall thickness of the fuel elements sampled varies from 0.25 to 0.50 mm (0.010 to 0.020 in.).

  4. Radiation processed polychloroprene-co-ethylene-propene diene terpolymer blends: Effect of radiation vulcanization on solvent transport kinetics

    NASA Astrophysics Data System (ADS)

    Dubey, K. A.; Bhardwaj, Y. K.; Chaudhari, C. V.; Kumar, Virendra; Goel, N. K.; Sabharwal, S.

    2009-03-01

    Blends of polychloroprene rubber (PCR) and ethylene propylene diene terpolymer rubber (EPDM) of different compositions were made and exposed to different gamma radiation doses. The radiation sensitivity and radiation vulcanization efficiency of blends was estimated by gel-content analysis, Charlesby-Pinner parameter determination and crosslinking density measurements. Gamma radiation induced crosslinking was most efficient for EPDM ( p0/ q0 ˜ 0.08), whereas it was the lowest for blends containing 40% PCR ( p0/ q0 ˜ 0.34). The vulcanized blends were characterized for solvent diffusion characteristics by following the swelling dynamics. Blends with higher PCR content showed anomalous swelling. The sorption and permeability of the solvent were not strictly in accordance with each other and the extent of variation in two parameters was found to be a function of blend composition. The Δ G values for solvent diffusion were in the range -2.97 to -9.58 kJ/mol and indicated thermodynamically favorable sorption for all blends. These results were corroborated by dynamic swelling, experimental as well as simulated profiles and have been explained on the basis of correlation between crosslinking density, diffusion kinetics, thermodynamic parameters and polymer-polymer interaction parameter.

  5. 2015 Los Alamos Space Weather Summer School Research Reports

    SciTech Connect

    Cowee, Misa; Chen, Yuxi; Desai, Ravindra; Hassan, Ehab; Kalmoni, Nadine; Lin, Dong; Depascuale, Sebastian; Hughes, Randall Scott; Zhou, Hong

    2015-11-24

    The fifth Los Alamos Space Weather Summer School was held June 1st - July 24th, 2015, at Los Alamos National Laboratory (LANL). With renewed support from the Institute of Geophysics, Planetary Physics, and Signatures (IGPPS) and additional support from the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) Office of Science, we hosted a new class of five students from various U.S. and foreign research institutions. The summer school curriculum includes a series of structured lectures as well as mentored research and practicum opportunities. Lecture topics including general and specialized topics in the field of space weather were given by a number of researchers affiliated with LANL. Students were given the opportunity to engage in research projects through a mentored practicum experience. Each student works with one or more LANL-affiliated mentors to execute a collaborative research project, typically linked with a larger ongoing research effort at LANL and/or the student’s PhD thesis research. This model provides a valuable learning experience for the student while developing the opportunity for future collaboration. This report includes a summary of the research efforts fostered and facilitated by the Space Weather Summer School. These reports should be viewed as work-in-progress as the short session typically only offers sufficient time for preliminary results. At the close of the summer school session, students present a summary of their research efforts. Titles of the papers included in this report are as follows: Full particle-in-cell (PIC) simulation of whistler wave generation, Hybrid simulations of the right-hand ion cyclotron anisotropy instability in a sub-Alfvénic plasma flow, A statistical ensemble for solar wind measurements, Observations and models of substorm injection dispersion patterns, Heavy ion effects on Kelvin-Helmholtz instability: hybrid study, Simulating plasmaspheric electron densities with a two

  6. Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory

    NASA Technical Reports Server (NTRS)

    Spjeldvik, W. N.

    1981-01-01

    Computer simulations of processes which control the relative abundances of ions in the trapping regions of geospace are compared with observations from discriminating ion detectors. Energy losses due to Coulomb collisions between ions and exospheric neutrals are considered, along with charge exchange losses and internal charge exchanges. The time evolution of energetic ion fluxes of equatorially mirroring ions under radial diffusion is modelled to include geomagnetic and geoelectric fluctutations. Limits to the validity of diffusion transport theory are discussed, and the simulation is noted to contain provisions for six ionic charge states and the source effect on the radiation belt oxygen ion distributions. Comparisons are made with ion flux data gathered on Explorer 45 and ISEE-1 spacecraft and results indicate that internal charge exchanges cause the radiation belt ion charge state to be independent of source charge rate characteristics, and relative charge state distribution is independent of the radially diffusive transport rate below the charge state redistribution zone.

  7. Geology and physical properties of the near-surface rocks of Mesita de los Alamos, Los Alamos County, New Mexico

    USGS Publications Warehouse

    Purtymun, W.D.

    1967-01-01

    The surface of Mesita de los Alamos is formed by units 2b and 3 of the Tshirege Member of the Bandelier Tuff. These units dip gently east-southeastward at 3 to 6 degrees. The units are faulted near the center of the mesa by a north-south trending normal strike slip fault, that is downthrown about 14 feet to the east. The units east of the fault have moved about 14 feet south relative to the units on the west side of the fault. Units 2b and 3 have bulk density values ranging from 80 to 120 pounds per cubic foot. The moisture content of the tuff below the soil zone and near surface tuff was less than 5 percent by volume in five of the 25 test holes drilled during a foundation investigation for the Meson Facility. The temperature of the tuff in the bottom of three test holes (depth 16 to 43 feet) varied from 50?F to 54?F. Temperature variations were a function of density and amount of solar radiation.

  8. Resonant electronic transport through a triple quantum-dot with Λ-type level structure under dual radiation fields

    SciTech Connect

    Guan, Chun; Xing, Yunhui; Zhang, Chao; Ma, Zhongshui

    2014-08-14

    Due to quantum interference, light can transmit through dense atomic media, a phenomenon known as electromagnetically induced transparency (EIT). We propose that EIT is not limited to light transmission and there is an electronic analog where resonant transparency in charge transport in an opaque structure can be induced by electromagnetic radiation. A triple-quantum-dots system with Λ-type level structure is generally opaque due to the level in the center dot being significantly higher and therefore hopping from the left dot to the center dot is almost forbidden. We demonstrate that an electromagnetically induced electron transparency (EIET) in charge of transport can indeed occur in the Λ-type system. The direct evidence of EIET is that an electron can travel from the left dot to the right dot, while the center dot apparently becomes invisible. We analyze EIET and the related shot noise in both the zero and strong Coulomb blockade regimes. It is found that the EIET (position, height, and symmetry) can be tuned by several controllable parameters of the radiation fields, such as the Rabi frequencies and detuning frequencies. The result offers a transparency/opaque tuning technique in charge transport using interfering radiation fields.

  9. Development of Parallel Computing Framework to Enhance Radiation Transport Code Capabilities for Rare Isotope Beam Facility Design

    SciTech Connect

    Kostin, Mikhail; Mokhov, Nikolai; Niita, Koji

    2013-09-25

    A parallel computing framework has been developed to use with general-purpose radiation transport codes. The framework was implemented as a C++ module that uses MPI for message passing. It is intended to be used with older radiation transport codes implemented in Fortran77, Fortran 90 or C. The module is significantly independent of radiation transport codes it can be used with, and is connected to the codes by means of a number of interface functions. The framework was developed and tested in conjunction with the MARS15 code. It is possible to use it with other codes such as PHITS, FLUKA and MCNP after certain adjustments. Besides the parallel computing functionality, the framework offers a checkpoint facility that allows restarting calculations with a saved checkpoint file. The checkpoint facility can be used in single process calculations as well as in the parallel regime. The framework corrects some of the known problems with the scheduling and load balancing found in the original implementations of the parallel computing functionality in MARS15 and PHITS. The framework can be used efficiently on homogeneous systems and networks of workstations, where the interference from the other users is possible.

  10. A Journey From Sandia To Los Alamos - 12465

    SciTech Connect

    Goyal, K.K.; Humphrey, B.J.; Krause, T.J.; Gluth, J.W.; Kiefer, M.L.; Haynes, S.

    2012-07-01

    The U.S. Department of Energy (DOE) relies on laboratory experiments and computer-based models to verify the reliability of the nation's nuclear stockpile. Sandia National Laboratories/New Mexico (SNL/NM) tests various materials in extreme environments designed to mimic those of nuclear explosions using the Z machine. The Z machine is a key tool in the National Nuclear Security Administration's (NNSA) stockpile stewardship mission and is used to study the dynamic properties of nuclear weapon materials. In 2006, SNL/NM and Los Alamos National Laboratory (LANL) signed a Memorandum of Understanding (MOU) defining experiments to be conducted in the Z machine involving plutonium (Pu) provided by LANL. Five Pu experiments have been completed with as many as 20 more planned through 2016. The experimental containment vessel used for the experiment and containing the Pu residues, becomes transuranic (TRU) waste after the experiment and termination of safeguards and is considered a LANL waste stream. Each containment vessel is placed in a 55-gallon Type A drum or standard waste box (SWB) for shipment back to LANL for final certification and eventual disposal at the Waste Isolation Pilot Plant (WIPP). The experimental containment vessels are greater than 99% metallic materials (ferrous and non-ferrous metals). In addition to the Pu targets, detonators with high explosives (HE) are used in the experiments to isolate the containment vessel from the Z machine as energy is delivered to the Pu samples. The characterization requirements, transportation issues, required documentation, and the approvals needed before shipments were challenging and required close coordination between SNL/NM, Sandia Site Office, LANL, Los Alamos Site Office, Washington TRU Solutions, Inc., the Central Characterization Project, and the Carlsbad Field Office. Between 2006 and 2010, representatives from SNL/NM and LANL worked to develop an approved path forward to meet the requirements of all stakeholders

  11. Environmental Surveillance at Los Alamos during 2007

    SciTech Connect

    2008-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) Environmental Directorate, as required by US Department of Energy Order 450.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2007. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, air; Chapters 5 and 6, water and sediments; Chapter 7, soils; and Chapter 8, foodstuffs and biota) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the laboratory’s technical areas and their associated programs, and Appendix D provides web links to more information. In printed copies of this report or Executive Summary, we have

  12. Comparison of Uncertainty of Two Precipitation Prediction Models at Los Alamos National Lab Technical Area 54

    SciTech Connect

    Shield, Stephen Allan; Dai, Zhenxue

    2015-08-18

    Meteorological inputs are an important part of subsurface flow and transport modeling. The choice of source for meteorological data used as inputs has significant impacts on the results of subsurface flow and transport studies. One method to obtain the meteorological data required for flow and transport studies is the use of weather generating models. This paper compares the difference in performance of two weather generating models at Technical Area 54 of Los Alamos National Lab. Technical Area 54 is contains several waste pits for low-level radioactive waste and is the site for subsurface flow and transport studies. This makes the comparison of the performance of the two weather generators at this site particularly valuable.

  13. Environmental assessment for the proposed CMR Building upgrades at the Los Alamos National Laboratory, Los Alamos, New Mexico. Final document

    SciTech Connect

    1997-02-04

    In order to maintain its ability to continue to conduct uninterrupted radioactive and metallurgical research in a safe, secure, and environmentally sound manner, the US Department of Energy (DOE) proposes to upgrade the Los Alamos National Laboratory (LANL) Chemistry and Metallurgy Research (CMR) Building. The building was built in the early 1950s to provide a research and experimental facility for analytical chemistry, plutonium and uranium chemistry, and metallurgy. Today, research and development activities are performed involving nuclear materials. A variety of radioactive and chemical hazards are present. The CMR Building is nearing the end of its original design life and does not meet many of today`s design codes and standards. The Proposed Action for this Environmental Assessment (EA) includes structural modifications to some portions of the CMR Building which do not meet current seismic criteria for a Hazard Category 2 Facility. Also included are upgrades and improvements in building ventilation, communications, monitoring, and fire protection systems. This EA analyzes the environmental effects of construction of the proposed upgrades. The Proposed Action will have no adverse effects upon agricultural and cultural resources, wetlands and floodplains, endangered and threatened species, recreational resources, or water resources. The Proposed Action would have negligible effects on human health and transportation, and would not pose a disproportionate adverse health or environmental impact on minority or low-income populations within an 80 kilometer (50 mile) radius of the CMR Building.

  14. [Peculiarities of ion transport of calcium in tumor cells under conditions of irradiation by ionizing radiation, chemopreparations and homeopathic means].

    PubMed

    Mikhvetadze, A V; Nadateĭshvili, G G

    2006-11-01

    The goal of given investigation was to reveal an effect of different agents on ion transport of Ca2+ in tumor cells (Erlich's carcinomas). Ionizing radiation, antitumor preparation vinkristin as well as homeopathic means - stimulated phosphoric acid diluted at 10-14 were used. Small doses of radiation (0,05 and 0,1 Gr) always had a stimulating effect on ion transport even in combination with vinkristin, which separately always depressed it. Both separately and in any combination stimulated phosphoric acid always reinforced transmembrane ion transport. In regard to Ca2+ a hypothesis about its participation in the process of reparation of tumor cell has been suggested. At increasing of Ca2+ concentrations a transmembrane transport of this ion in the environment increases what induces strengthening of adhesive properties of the cell. However, it is known that in tumors these properties are decreased. Apparently, in this case two contrary processes - strengthening and decrease of adhesive properties take place pointing to the fact that there appear reparative forces in tumor process.

  15. A generalized framework for in-line energy deposition during steady-state Monte Carlo radiation transport

    SciTech Connect

    Griesheimer, D. P.; Stedry, M. H.

    2013-07-01

    A rigorous treatment of energy deposition in a Monte Carlo transport calculation, including coupled transport of all secondary and tertiary radiations, increases the computational cost of a simulation dramatically, making fully-coupled heating impractical for many large calculations, such as 3-D analysis of nuclear reactor cores. However, in some cases, the added benefit from a full-fidelity energy-deposition treatment is negligible, especially considering the increased simulation run time. In this paper we present a generalized framework for the in-line calculation of energy deposition during steady-state Monte Carlo transport simulations. This framework gives users the ability to select among several energy-deposition approximations with varying levels of fidelity. The paper describes the computational framework, along with derivations of four energy-deposition treatments. Each treatment uses a unique set of self-consistent approximations, which ensure that energy balance is preserved over the entire problem. By providing several energy-deposition treatments, each with different approximations for neglecting the energy transport of certain secondary radiations, the proposed framework provides users the flexibility to choose between accuracy and computational efficiency. Numerical results are presented, comparing heating results among the four energy-deposition treatments for a simple reactor/compound shielding problem. The results illustrate the limitations and computational expense of each of the four energy-deposition treatments. (authors)

  16. Los Alamos National Laboratory Prepares for Fire Season

    SciTech Connect

    L’Esperance, Manny

    2016-07-18

    Through the establishment of a Wildland Fire Program Office, and the Interagency Fire Base located on Laboratory property, Los Alamos National Laboratory is continuing and improving a program to prepare for wildland fire.

  17. Explosive Flux Compression: 50 Years of Los Alamos Activities

    SciTech Connect

    Fowler, C.M.; Thomson, D.B.; Garn, W.B.

    1998-10-18

    Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail.

  18. Los Alamos National Laboratory Prepares for Fire Season

    ScienceCinema

    L’Esperance, Manny

    2016-08-10

    Through the establishment of a Wildland Fire Program Office, and the Interagency Fire Base located on Laboratory property, Los Alamos National Laboratory is continuing and improving a program to prepare for wildland fire.

  19. Explosive Flux Compression:. 50 Years of LOS Alamos Activities

    NASA Astrophysics Data System (ADS)

    Fowler, C.; Thomson, D.; Garn, W.

    2004-11-01

    Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail.

  20. Radiation Effects on the Sorption and Mobilization of Radionuclide during Transport through the Geosphere

    SciTech Connect

    L.M. Wang; R.C. Eqing; K.F. Hayes

    2004-03-14

    Site restoration activities at DOE facilities and the permanent disposal of nuclear waste inevitably involve understanding the behavior of materials in a radiation field. Radionuclide decay and the associated radiation fields lead to physical and chemical changes that can degrade or enhance important material properties. Alpha-decay of the actinide elements and beta-decay of the fission products lead to atomic-scale changes in materials (radiation damage and transmutation).

  1. Neutron, proton, and photonuclear cross-sections for radiation therapy and radiation protection.

    PubMed

    Chadwick, M B

    1998-12-01

    I review recent work at Los Alamos undertaken to evaluate neutron, proton, and photonuclear cross-sections up to 150 MeV (to 250 MeV for protons), based on experimental data and nuclear model calculations. These data are represented in the ENDF format and can be used in computer codes to simulate radiation transport. They permit calculations of absorbed dose in the body from therapy beams, and through use of kerma coefficients allow absorbed dose to be estimated for a given neutron energy distribution. In radiation protection, these data can be used to determine shielding requirements in accelerator environments and to calculate neutron, proton, gamma-ray, and radionuclide production. Illustrative comparisons of the evaluated cross-section and kerma coefficient data with measurements are given.

  2. Radiated Sound of a High-Speed Water-Jet-Propelled Transportation Vessel.

    PubMed

    Rudd, Alexis B; Richlen, Michael F; Stimpert, Alison K; Au, Whitlow W L

    2016-01-01

    The radiated noise from a high-speed water-jet-propelled catamaran was measured for catamaran speeds of 12, 24, and 37 kn. The radiated noise increased with catamaran speed, although the shape of the noise spectrum was similar for all speeds and measuring hydrophone depth. The spectra peaked at ~200 Hz and dropped off continuously at higher frequencies. The radiated noise was 10-20 dB lower than noise from propeller-driven ships at comparable speeds. The combination of low radiated noise and high speed could be a factor in the detection and avoidance of water-jet-propelled ships by baleen whales.

  3. Strategic defense initiatives at Los Alamos National Laboratory

    SciTech Connect

    Rockwood, S.D.

    1985-01-01

    This presentation reviews the Strategic Defense Initiative (SDI) programs at Los Alamos National Laboratory, noting especially the needs for and applications of optics and optical technologies. Table I lists the various activities at Los Alamos contributing to SDI programs. The principal, nonnuclear SDI programs are: (1) the free-electron laser, and (2) neutral particle beams. Both should be considered as potential long-range-kill systems, but still in the futuristic category.

  4. Los Alamos upgrade in metallographic capabilities

    SciTech Connect

    Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

    1985-01-01

    The Los Alamos Wing 9 Hot Cell Facility is in the process of upgrading their metallographic sample preparation and examination capability. The present capability to grind, polish and etch samples from reactor fuels and materials has been in operation for 18 years. Macro photography and alpha and beta-gamma autoradiography are an important part of this capability. Some of the fast breeder reactor experiments have contained sodium as a coolant. Therefore, the capability to distill sodium from some samples scheduled for microstructural examinations is a requirement. Since the reactor fuel samples are highly radioactive and contain plutonium, either as fabricated or as a result of breeding during reactor service, these samples must be handled in shielded hot cells containing alpha boxes to isolate the plutonium and hazardous fission products from personnel and the environment. The present equipment that was designed and built into those alpha boxes has functioned very well for the past 18 years. During that time the technicians have thought of ways to improve the equipment to do the work faster and safer. These ideas and ideas that have been developed during the design of new alpha boxes and new equipment for microstructural sample preparation have provided the concepts for the capability to perform the work faster and maintain the equipment in a safer manner.

  5. Saving Water at Los Alamos National Laboratory

    ScienceCinema

    Erickson, Andy

    2016-07-12

    Los Alamos National Laboratory decreased its water usage by 26 percent in 2014, with about one-third of the reduction attributable to using reclaimed water to cool a supercomputing center. The Laboratory's goal during 2014 was to use only re-purposed water to support the mission at the Strategic Computing Complex. Using reclaimed water from the Sanitary Effluent Reclamation Facility, or SERF, substantially decreased water usage and supported the overall mission. SERF collects industrial wastewater and treats it for reuse. The reclamation facility contributed more than 27 million gallons of re-purposed water to the Laboratory's computing center, a secured supercomputing facility that supports the Laboratory’s national security mission and is one of the institution’s larger water users. In addition to the strategic water reuse program at SERF, the Laboratory reduced water use in 2014 by focusing conservation efforts on areas that use the most water, upgrading to water-conserving fixtures, and repairing leaks identified in a biennial survey.

  6. Oxidative lime pretreatment of Alamo switchgrass.

    PubMed

    Falls, Matthew; Holtzapple, Mark T

    2011-09-01

    Previous studies have shown that oxidative lime pretreatment is an effective delignification method that improves the enzymatic digestibility of many biomass feedstocks. The purpose of this work is to determine the recommended oxidative lime pretreatment conditions (reaction temperature, time, pressure, and lime loading) for Alamo switchgrass (Panicum virgatum). Enzymatic hydrolysis of glucan and xylan was used to determine the performance of the 52 studied pretreatment conditions. The recommended condition (110°C, 6.89 bar O(2), 240 min, 0.248 g Ca(OH)(2)/g biomass) achieved glucan and xylan overall yields (grams of sugar hydrolyzed/100 g sugar in raw biomass, 15 filter paper units (FPU)/g raw glucan) of 85.9 and 52.2, respectively. In addition, some glucan oligomers (2.6 g glucan recovered/100 g glucan in raw biomass) and significant levels of xylan oligomers (26.0 g xylan recovered/100 g xylan in raw biomass) were recovered from the pretreatment liquor. Combining a decrystallization technique (ball milling) with oxidative lime pretreatment further improved the overall glucan yield to 90.0 (7 FPU/g raw glucan).

  7. Historic Manhattan Project Sites at Los Alamos

    ScienceCinema

    McGehee, Ellen

    2016-07-12

    The Manhattan Project laboratory constructed at Los Alamos, New Mexico, beginning in 1943, was intended from the start to be temporary and to go up with amazing speed. Because most of those WWII-era facilities were built with minimal materials and so quickly, much of the original infrastructure was torn down in the late '40s and early '50s and replaced by more permanent facilities. However, a few key facilities remained, and are being preserved and maintained for historic significance. Four such sites are visited briefly in this video, taking viewers to V-Site, the buildings where the first nuclear explosive device was pre-assembled in preparation for the Trinity Test in Southern New Mexico. Included is another WWII area, Gun Site. So named because it was the area where scientists and engineers tested the so-called "gun method" of assembling nuclear materials -- the fundamental design of the Little Boy weapon that was eventually dropped on Hiroshima. The video also goes to Pajarito Site, home of the "Slotin Building" and "Pond Cabin." The Slotin Building is the place where scientist Louis Slotin conducted a criticality experiment that went awry in early 1946, leading to his unfortunate death, and the Pond Cabin served the team of eminent scientist Emilio Segre who did early chemistry work on plutonium that ultimately led to the Fat Man weapon.

  8. Historic Manhattan Project Sites at Los Alamos

    SciTech Connect

    McGehee, Ellen

    2014-05-22

    The Manhattan Project laboratory constructed at Los Alamos, New Mexico, beginning in 1943, was intended from the start to be temporary and to go up with amazing speed. Because most of those WWII-era facilities were built with minimal materials and so quickly, much of the original infrastructure was torn down in the late '40s and early '50s and replaced by more permanent facilities. However, a few key facilities remained, and are being preserved and maintained for historic significance. Four such sites are visited briefly in this video, taking viewers to V-Site, the buildings where the first nuclear explosive device was pre-assembled in preparation for the Trinity Test in Southern New Mexico. Included is another WWII area, Gun Site. So named because it was the area where scientists and engineers tested the so-called "gun method" of assembling nuclear materials -- the fundamental design of the Little Boy weapon that was eventually dropped on Hiroshima. The video also goes to Pajarito Site, home of the "Slotin Building" and "Pond Cabin." The Slotin Building is the place where scientist Louis Slotin conducted a criticality experiment that went awry in early 1946, leading to his unfortunate death, and the Pond Cabin served the team of eminent scientist Emilio Segre who did early chemistry work on plutonium that ultimately led to the Fat Man weapon.

  9. Saving Water at Los Alamos National Laboratory

    SciTech Connect

    Erickson, Andy

    2015-03-16

    Los Alamos National Laboratory decreased its water usage by 26 percent in 2014, with about one-third of the reduction attributable to using reclaimed water to cool a supercomputing center. The Laboratory's goal during 2014 was to use only re-purposed water to support the mission at the Strategic Computing Complex. Using reclaimed water from the Sanitary Effluent Reclamation Facility, or SERF, substantially decreased water usage and supported the overall mission. SERF collects industrial wastewater and treats it for reuse. The reclamation facility contributed more than 27 million gallons of re-purposed water to the Laboratory's computing center, a secured supercomputing facility that supports the Laboratory’s national security mission and is one of the institution’s larger water users. In addition to the strategic water reuse program at SERF, the Laboratory reduced water use in 2014 by focusing conservation efforts on areas that use the most water, upgrading to water-conserving fixtures, and repairing leaks identified in a biennial survey.

  10. Audit of consultant agreements at Los Alamos National Laboratory

    SciTech Connect

    1996-02-23

    The Department of Energy`s (Department) Albuquerque Operations Office (Albuquerque) and Los Alamos National Laboratory (Los Alamos) are responsible for acquiring consulting services in a manner most advantageous to the Government by ensuring adequate competition. Although the Department prefers competitively awarding subcontracts, including consultant agreements, to ensure the lowest possible cost, it allows sole sourcing a subcontract if the sole source is fully justified. The objective of the audit was to determine whether Los Alamos` consultant agreements contained adequate sole source justifications. The audit showed that Los Alamos may not have acquired some of its consultant agreements at the lowest possible cost because it did not prepare adequate sole source justifications for 17 sole source consultant agreements valued at $842,900. This condition existed because: (1) requesters did not follow policies and procedures when preparing sole source justifications, (2) Los Alamos did not have an internal mechanism to reject consultant agreements that were not adequately justified, and (3) the Department did not review consultant agreements to evaluate the adequacy of sole source justifications. Without adequate justifications, the Department cannot be assured that consultant services were obtained at the lowest possible cost. We therefore recommended that the Manager, Albuquerque Operations Office require Los Alamos to ensure proper sole source justifications and enhance internal controls over consultant agreements. Management agreed to implement the recommendations.

  11. Radiation

    NASA Video Gallery

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  12. Los Alamos National Laboratory Yucca Mountain Project Publications (1979-1996)

    SciTech Connect

    Ruhala, E.R.; Klein, S.H.

    1997-06-01

    This over-350 title publication list reflects the accomplishments of Los Alamos Yucca Mountain Site Characterization Project researchers, who, since 1979, have been conducting multidisciplinary research to help determine if Yucca Mountain, Nevada, is a suitable site for a high-level waste repository. The titles can be accessed in two ways: by year, beginning with 1996 and working back to 1979, and by subject area: mineralogy/petrology/geology, volcanism, radionuclide solubility/ground-water chemistry; radionuclide sorption and transport; modeling/validation/field studies; summary/status reports, and quality assurance.

  13. Los Alamos National Laboratory Yucca Mountain Project publications (1979--1994)

    SciTech Connect

    Bowker, L.M.; Espinosa, M.L.; Klein, S.H.

    1995-11-01

    This over-300 title publication list reflects the accomplishments of Los Alamos Yucca Mountain Site Characterization Project researchers, who, since 1979, have been conducting multidisciplinary research to help determine if Yucca Mountain, Nevada, is a suitable site for a high-level waste repository. The titles can be accessed in two ways: by year, beginning with 1994 and working back to 1979, and by subject area: mineralogy/petrology/geology, volcanism, radionuclide solubility/groundwater chemistry; radionuclide sorption and transport; modeling/validation/field studies; summary/status reports, and quality assurance.

  14. TRANSPORT

    EPA Science Inventory

    Presentation outline: transport principles, effective solubility; gasoline composition; and field examples (plume diving).
    Presentation conclusions: MTBE transport follows from - phyiscal and chemical properties and hydrology. Field examples show: MTBE plumes > benzene plu...

  15. Radiation environment at the Moon: Comparisons of transport code modeling and measurements from the CRaTER instrument

    NASA Astrophysics Data System (ADS)

    Porter, Jamie A.; Townsend, Lawrence W.; Spence, Harlan; Golightly, Michael; Schwadron, Nathan; Kasper, Justin; Case, Anthony W.; Blake, John B.; Zeitlin, Cary

    2014-06-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER), an instrument carried on the Lunar Reconnaissance Orbiter spacecraft, directly measures the energy depositions by solar and galactic cosmic radiations in its silicon wafer detectors. These energy depositions are converted to linear energy transfer (LET) spectra. High LET particles, which are mainly high-energy heavy ions found in the incident cosmic ray spectrum, or target fragments and recoils produced by protons and heavier ions, are of particular importance because of their potential to cause significant damage to human tissue and electronic components. Aside from providing LET data useful for space radiation risk analyses for lunar missions, the observed LET spectra can also be used to help validate space radiation transport codes, used for shielding design and risk assessment applications, which is a major thrust of this work. In this work the Monte Carlo transport code HETC-HEDS (High-Energy Transport Code-Human Exploration and Development in Space) is used to estimate LET contributions from the incident primary ions and their charged secondaries produced by nuclear collisions as they pass through the three pairs of silicon detectors. Also in this work, the contributions to the LET of the primary ions and their charged secondaries are analyzed and compared with estimates obtained using the deterministic space radiation code HZETRN 2010, developed at NASA Langley Research Center. LET estimates obtained from the two transport codes are compared with measurements of LET from the CRaTER instrument during the mission. Overall, a comparison of the LET predictions of the HETC-HEDS code to the predictions of the HZETRN code displays good agreement. The code predictions are also in good agreement with the CRaTER LET measurements above 15 keV/µm but differ from the measurements for smaller values of LET. A possible reason for this disagreement between measured and calculated spectra below 15 keV/µm is an

  16. Physics-based, reduced-order gas cloud with radiative transport model for rapid simulation of hyperspectral infrared sensors

    NASA Astrophysics Data System (ADS)

    Kottke, Peter A.; Fedorov, Andrei G.

    2012-05-01

    We have developed a reduced-order, physics-based model of gas cloud transport and combined it with an approximate formulation of the equation of radiative transport to enable efficient prediction of spectral irradiation for simulation of hyperspectral infrared sensors. The resulting combined model is easily implemented, providing a rapid and flexible in silico experimentation capability. The gas cloud model is based on the entrainment hypothesis and predicts cloud trajectories in three-dimensions, with elevation changes occurring primarily due to buoyancy effects and with spreading and accompanying dilution and cooling occurring due to a turbulence dominated growth mechanism. The radiation transport model is simplified through an approximate treatment of scattering that transforms the governing equation from an integro-differential equation to an ordinary differential equation. The conjugate model has been combined with a simple sensor model and has been validated through comparison to results from large-scale field tests. The utility of the simulations has also been demonstrated through inclusion in a larger algorithm development and analysis program, the chem/bio algorithm development kit.

  17. Recent UCN source developments at Los Alamos

    SciTech Connect

    Seestrom, S.J.; Anaya, J.M.; Bowles, T.J.

    1998-12-01

    The most intense sources of ultra cold neutrons (UCN) have bee built at reactors where the high average thermal neutron flux can overcome the low UCN production rate to achieve usable densities of UCN. At spallation neutron sources the average flux available is much lower than at a reactor, though the peak flux can be comparable or higher. The authors have built a UCN source that attempts to take advantage of the high peak flux available at the short pulse spallation neutron source at the Los Alamos Neutron Science Center (LANSCE) to generate a useful number of UCN. In the source UCN are produced by Doppler-shifted Bragg scattering of neutrons to convert 400-m/s neutrons down into the UCN regime. This source was initially tested in 1996 and various improvements were made based on the results of the 1996 running. These improvements were implemented and tested in 1997. In sections 2 and 3 they discuss the improvements that have been made and the resulting source performance. Recently an even more interesting concept was put forward by Serebrov et al. This involves combining a solid Deuterium UCN source, previously studied by Serebrov et al., with a pulsed spallation source to achieve world record UCN densities. They have initiated a program of calculations and measurements aimed at verifying the solid Deuterium UCN source concept. The approach has been to develop an analytical capability, combine with Monte Carlo calculations of neutron production, and perform benchmark experiments to verify the validity of the calculations. Based on the calculations and measurements they plan to test a modified version of the Serebrov UCN factory. They estimate that they could produce over 1,000 UCN/cc in a 15 liter volume, using 1 {micro}amp of 800 MeV protons for two seconds every 500 seconds. They will discuss the result UCN production measurements in section 4.

  18. Simulations of flow interactions near Los Alamos

    SciTech Connect

    Costigan, K. R.; Winterkamp, Judy; Bossert, J. E.; Langley, D. L.

    2002-01-01

    The Pajarito Plateau is located on the eastern flank of the Jemez Mountains and the west side of the Rio Grande Valley, in north-central New Mexico, where the river runs roughly north to south. On the Pajarito Plateau, a network of surface meteorological stations has been routinely maintained by Los Alamos National Laboratory. This network includes five instrumented towers, within an approximately 10 km by 15 km area. The towers stand from 23 m to 92 m tall, with multiple wind measurement heights. Investigation of the station records indicates that the wind fields can be quite complicated and may be the result of interactions of thermally and/or dynamically driven flows of many scales. Slope flows are often found on the plateau during the morning and evening transition times, but it is not unusual to find wind directions that are inconsistent with slope flows at some or all of the stations. It has been speculated that valley circulations, as well as synoptically driven winds, interact with the slope flows, but the mesonet measurements alone, with no measurements in the remainder of the valley, were not sufficient to investigate this hypothesis. Thus, during October of 1995, supplemental meteorological instrumentation was placed in the Rio Grande basin to study the complex interaction of flows in the area. A sodar was added near the 92 m tower and a radar wind profiler was placed in the Rio Grande Valley, just east of the plateau and near the river. Measurements were also added at the top of Pajarito Mountain, just west of the plateau, and across the valley, to the east, on top of Tesuque Peak (in the Sangre de Cristo Mountains). Two surface stations were also added to the north-facing slopes of Pajarito Mountain. This paper will present observations from October 1995 and results of simulations of this area that are used in the study of the complex interaction of dynamically and thermally driven flows on multiple scales.

  19. Measurements of the linear energy transfer spectra on the Mir orbital station and comparison with radiation transport models

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Konradi, A.; Atwell, W.; Golightly, M. J.; Cucinotta, F. A.; Wilson, J. W.; Petrov, V. M.; Tchernykh, I. V.; Shurshakov, V. A.; Lobakov, A. P.

    1996-01-01

    A tissue equivalent proportional counter designed to measure the linear energy transfer spectra (LET) in the range 0.2-1250 keV/micrometer was flown in the Kvant module on the Mir orbital station during September 1994. The spacecraft was in a 51.65 degrees inclination, elliptical (390 x 402 km) orbit. This is nearly the lower limit of its flight altitude. The total absorbed dose rate measured was 411.3 +/- 4.41 microGy/day with an average quality factor of 2.44. The galactic cosmic radiation (GCR) dose rate was 133.6 microGy/day with a quality factor of 3.35. The trapped radiation belt dose rate was 277.7 microGy/day with an average quality factor of 1.94. The peak rate through the South Atlantic Anomaly was approximately 12 microGy/min and nearly constant from one pass to another. A detailed comparison of the measured LET spectra has been made with radiation transport models. The GCR results are in good agreement with model calculations; however, this is not the case for radiation belt particles and again points to the need for improving the AP8 omni-directional trapped proton models.

  20. [Hygienic evaluation of the effectiveness of the use of impulse ultraviolet radiation sources in railway transport].

    PubMed

    Poliakova, V A; Gipp, E K; Shashkovskiĭ, S G; Shashkovskiĭ, M G

    2000-01-01

    The paper covers the use of impulse ultraviolet radiation sources for disinfecting the air and inside surfaces of the premises of railway station buildings and the water of long-distance passenger trains.

  1. Supersonic radiative transport of electron-hole plasma in semiconductors at room temperature studied by laser ultrasonics

    NASA Astrophysics Data System (ADS)

    Gao, W.; Gusev, V.; Glorieux, C.; Thoen, J.; Borghs, G.

    1997-02-01

    A piezoelectric semiconductor CdS 1- xSe x crystal under external electric loading was excited by pulsed nanosecond ultraviolet laser radiation. Acoustic waves were excited via the inverse piezoelectric effect due to the screening of the external electric field by expanding the space distribution of photogenerated electrons and holes. The duration of the interferometrically detected longitudinal acoustic pulses indicated that both the expansion of the screened region in space and the electron-hole plasma expansion are supersonic at the time scale of laser action. The value of 2 × 10 3 cm 2/s obtained for the electron-hole plasma diffusivity leads to the conclusion that the mechanism of this fast carrier transport is photon recycling, i.e. reabsorption of recombination radiation. This conclusion is also supported by the acoustic signals duration independence on magnitude and polarity of the external electric field.

  2. Dose reconstruction for weapons experiments involving {sup 140}La at Los Alamos National Laboratory, 1944-1962

    SciTech Connect

    Kraig, D.J.

    1997-10-01

    A series of 254 weapons design experiments was conducted by Los Alamos National Laboratory from 1944 through 1962 and resulted in the dispersal of approximately 11 PBq (300 kCi) of radioactive {sup 140}La. All shots occurred at Point Able in Bayo Canyon, east of the Los Alamos townsite. Public interest and the Government Accounting Office probe precipitated a dose reconstruction to assess potential exposures to members of the public. The information available for each shot included explosive charge size, date and time of explosion, and shot activity. Detailed meteorological data were not available for the majority of the shots, requiring the development of statistically representative meteorological data. A wind rose was developed specific to the afternoon-evening time of the shots, and the wind frequency in each sector was used to determine the fraction of activity dispersed towards each hypothetical receptor. HOTSPOT 7, a Gaussian plume-based dispersion model, was used to determine the average dose per sector per unit of shot activity. The dose from penetrating radiation from ground-deposited {sup 140}La was greater by several orders of magnitude than the dose from inhalation and immersion. The highest doses to a permanent resident probably occurred in the easternmost part of the Los Alamos townsite. The highest annual dose occurred in 1955 and was approximately 0.23 mSv. Assuming an individual had been at the location of maximum potential exposure in the Los Alamos townsite continuously throughout the experiments, the total dose from the 18-y series would have been approximately 1.4 mSv with an average dose of approximately 0.09 mSv y{sup -1}. Doses at nearby Totavi trailer park, San Clara Pueblo, and Santa Clara Pueblo were approximately 75%, 40%, and 15%, respectively, of those at Los Alamos. Visitors to nearby public areas received negligible doses. 11 refs., 6 figs., 4 tabs.

  3. Initial results with the LLNL 2-D chemical-radiative-transport model of the troposphere and stratosphere

    SciTech Connect

    Wuebbles, D.J.; Connell, P.S.; Grant, K.E.; Tarp, R.; Taylor, K.E.

    1987-09-01

    Significant progress has been made at LLNL in the development of a zonally averaged (two-dimensional) chemical-radiative-transport model of the troposphere and stratosphere. Although further model development and refinement is being planned the LLNL 2-D model is currently ready to be applied to appropriately designed research studies of stratospheric chemical processes and interactions. Several such studies are now underway. This paper provides a description of the existing 2-D model and discusses some of the pertinent results for evaluating the capabilities of the model. Special attempts at improving the timing of the model are also discussed. 6 figs.

  4. ZERT Final Scientific Report Los Alamos National Laboratory

    SciTech Connect

    Pawar, Rajesh J.

    2011-01-01

    Los Alamos National Laboratory's (LANL) activities for the Center for Zero Emission Research and Technology (ZERT) have fallen into three broad research areas: (1) How do you reduce uncertainty in assuring prior to operation that an engineered geologic site will meet a specific performance goal (e.g., <0.01% leak per year)? (2) What are key monitoring needs for verifying that an engineered geologic site is meeting a performance goal? (3) What are potential vulnerabilities for breeches in containment of CO{sub 2}, and how could they be mitigated either prior to operation or in the event that a threshold is exceeded? We have utilized LANL's multi-disciplinary expertise and an integrated approach combining laboratory experiments, field observations and numerical simulations to address various research issues related to above-mentioned areas. While there have been a number of major milestones achieved as described in past quarterly reports, two of the major accomplishments resulting from LANL's efforts include: (1) Development of the CO{sub 2}-PENS systems framework for long-term performance analysis of geologic CO{sub 2} sequestration sites. CO{sub 2}-PENS is first-ever systems analysis tool designed for assessment of CO{sub 2} sequestration sites. (2) One of the few field studies to-date focused on understanding impact of CO{sub 2} leakage on shallow groundwater chemistry. Two major conclusions of the study are as follows: the impact of co-contaminants transported with deeper brine on shallow groundwater quality is likely to be much larger than that of the CO{sub 2} and CO{sub 2}-induced geochemical reactions and in certain geochemical environment the reactivity of pure CO{sub 2} will not be sufficient to mobilize metals beyond background levels.

  5. Initial performance of Los Alamos Advanced Free Electron Laser

    SciTech Connect

    Nguyen, D.C.; Baca, D.M.; Chan, K.C.D.; Cheairs, R.B.; Fortgang, C.M.; Gierman, S.M.; Johnson, W.J.D.; Holcomb, D.E.; Kinross-Wright, J.; McCann, S.W.; Meier, K.L.; Plato, J.G.; Sheffield, R.L.; Sherwood, B.A.; Sigler, F.E.; Timmer, C.A.; Warren, R.W.; Weber, M.E.; Wilson, W.L.

    1992-09-01

    We report recent results on the high-brightness electron linac and initial performance of the Advanced FEL at Los Alamos. The design and construction of the Advanced FEL beamline are based upon integration of advanced technologies such as high-brightness photoinjector, high-gradient compact linac, and permanent-magnet beamline components. With the use of microwiggler, both permanent magnet and pulsed electromagnet, and compact optical resonator, the Advanced FEL will be the first of its kind small enough to be mounted on an optical table and yet capable of providing highpower optical output spanning the near-ir and visible regions. A schematic of the Advanced FEL is shown in. The source of high-current electron pulses is a laser-gated photoelectron injector which forms-an integral part of a high-gradient 1.2-m long rf linear accelerator. The latter is capable of accelerating electrons up to 20 MeV with room temperature operation and 25 MeV at 77K. The electrons are produced in 10-ps pulses with peak currents as high as 300 A. These electron pulses are transported in a brightness-preserving beamline consisting of permanent magnet dipoles and quadrupoles. The beamline has three 30{degrees} bends. The first bend allows for the photocathode drive laser input; the second allows for the FEL output and the third turns the electron beam into the floor for safety reasons. Additional information on the design physics of the Advanced FEL can be found elsewhere.

  6. Initial performance of Los Alamos Advanced Free Electron Laser

    SciTech Connect

    Nguyen, D.C.; Baca, D.M.; Chan, K.C.D.; Cheairs, R.B.; Fortgang, C.M.; Gierman, S.M.; Johnson, W.J.D.; Holcomb, D.E.; Kinross-Wright, J.; McCann, S.W.; Meier, K.L.; Plato, J.G.; Sheffield, R.L.; Sherwood, B.A.; Sigler, F.E.; Timmer, C.A.; Warren, R.W.; Weber, M.E.; Wilson, W.L.

    1992-01-01

    We report recent results on the high-brightness electron linac and initial performance of the Advanced FEL at Los Alamos. The design and construction of the Advanced FEL beamline are based upon integration of advanced technologies such as high-brightness photoinjector, high-gradient compact linac, and permanent-magnet beamline components. With the use of microwiggler, both permanent magnet and pulsed electromagnet, and compact optical resonator, the Advanced FEL will be the first of its kind small enough to be mounted on an optical table and yet capable of providing highpower optical output spanning the near-ir and visible regions. A schematic of the Advanced FEL is shown in. The source of high-current electron pulses is a laser-gated photoelectron injector which forms-an integral part of a high-gradient 1.2-m long rf linear accelerator. The latter is capable of accelerating electrons up to 20 MeV with room temperature operation and 25 MeV at 77K. The electrons are produced in 10-ps pulses with peak currents as high as 300 A. These electron pulses are transported in a brightness-preserving beamline consisting of permanent magnet dipoles and quadrupoles. The beamline has three 30{degrees} bends. The first bend allows for the photocathode drive laser input; the second allows for the FEL output and the third turns the electron beam into the floor for safety reasons. Additional information on the design physics of the Advanced FEL can be found elsewhere.

  7. Experiences in the Performance Analysis and Optimization of a Deterministic Radiation Transport Code on the Cray SV1

    SciTech Connect

    Peter Cebull

    2004-05-01

    The Attila radiation transport code, which solves the Boltzmann neutron transport equation on three-dimensional unstructured tetrahedral meshes, was ported to a Cray SV1. Cray's performance analysis tools pointed to two subroutines that together accounted for 80%-90% of the total CPU time. Source code modifications were performed to enable vectorization of the most significant loops, to correct unfavorable strides through memory, and to replace a conjugate gradient solver subroutine with a call to the Cray Scientific Library. These optimizations resulted in a speedup of 7.79 for the INEEL's largest ATR model. Parallel scalability of the OpenMP version of the code is also discussed, and timing results are given for other non-vector platforms.

  8. Combining node-centered parallel radiation transport and higher-order multi-material cell-centered hydrodynamics methods in three-temperature radiation hydrodynamics code TRHD

    NASA Astrophysics Data System (ADS)

    Sijoy, C. D.; Chaturvedi, S.

    2016-06-01

    Higher-order cell-centered multi-material hydrodynamics (HD) and parallel node-centered radiation transport (RT) schemes are combined self-consistently in three-temperature (3T) radiation hydrodynamics (RHD) code TRHD (Sijoy and Chaturvedi, 2015) developed for the simulation of intense thermal radiation or high-power laser driven RHD. For RT, a node-centered gray model implemented in a popular RHD code MULTI2D (Ramis et al., 2009) is used. This scheme, in principle, can handle RT in both optically thick and thin materials. The RT module has been parallelized using message passing interface (MPI) for parallel computation. Presently, for multi-material HD, we have used a simple and robust closure model in which common strain rates to all materials in a mixed cell is assumed. The closure model has been further generalized to allow different temperatures for the electrons and ions. In addition to this, electron and radiation temperatures are assumed to be in non-equilibrium. Therefore, the thermal relaxation between the electrons and ions and the coupling between the radiation and matter energies are required to be computed self-consistently. This has been achieved by using a node-centered symmetric-semi-implicit (SSI) integration scheme. The electron thermal conduction is calculated using a cell-centered, monotonic, non-linear finite volume scheme (NLFV) suitable for unstructured meshes. In this paper, we have described the details of the 2D, 3T, non-equilibrium, multi-material RHD code developed with a special attention to the coupling of various cell-centered and node-centered formulations along with a suite of validation test problems to demonstrate the accuracy and performance of the algorithms. We also report the parallel performance of RT module. Finally, in order to demonstrate the full capability of the code implementation, we have presented the simulation of laser driven shock propagation in a layered thin foil. The simulation results are found to be in good

  9. LANSCE radiation security system (RSS)

    SciTech Connect

    Gallegos, F.R.

    1996-12-31

    The Radiation Security System (RSS) is an engineered safety system which automatically terminates transmission of accelerated ion beams in response to pre-defined abnormal conditions. It is one of the four major mechanisms used to protect people from radiation hazards induced by accelerated pulsed ion beams at the Los Alamos Neutron Science Center (LANSCE). The others are shielding, administrative policies and procedures, and qualified, trained personnel. Prompt radiation hazards at the half-mile long LANSCE accelerator exist due to average beam intensities ranging from 1 milli-amp for H{sup +} beam to 100 micro-amps for the high intensity H{sup {minus}} beam. Experimental programs are supplied with variable energy (maximum 800 MeV), pulse-width (maximum 1 msec), and pulse frequency (maximum 120 Hz) ion beams. The RSS includes personnel access control systems, beam spill monitoring systems, and beam current level limiting systems. It is a stand-alone system with redundant logic chains. A fault of the RSS will cause the insertion of fusible beam plugs in the accelerator low energy beam transport. The design philosophy, description, and operation of the RSS are described in this paper.

  10. Studies of HZE particle interactions and transport for space radiation protection purposes

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.; Wilson, John W.; Schimmerling, Walter; Wong, Mervyn

    1987-01-01

    The main emphasis is on developing general methods for accurately predicting high-energy heavy ion (HZE) particle interactions and transport for use by researchers in mission planning studies, in evaluating astronaut self-shielding factors, and in spacecraft shield design and optimization studies. The two research tasks are: (1) to develop computationally fast and accurate solutions to the Boltzmann (transport) equation; and (2) to develop accurate HZE interaction models, from fundamental physical considerations, for use as inputs into these transport codes. Accurate solutions to the HZE transport problem have been formulated through a combination of analytical and numerical techniques. In addition, theoretical models for the input interaction parameters are under development: stopping powers, nuclear absorption cross sections, and fragmentation parameters.

  11. 1993 Northern goshawk inventory on portions of Los Alamos National Laboratory, Los Alamos, NM. Final report

    SciTech Connect

    Sinton, D.T.; Kennedy, P.L.

    1994-06-01

    Northern goshawks (Accipiter gentilis) (hereafter referred to as goshawk) is a large forest dwelling hawk. Goshawks may be declining in population and reproduction in the southwestern United States. Reasons for the possible decline in goshawk populations include timber harvesting resulting in the loss of nesting habitat, toxic chemicals, and the effects of drought, fire, and disease. Thus, there is a need to determine their population status and assess impacts of management activities in potential goshawk habitat. Inventory for the goshawk was conducted on 2,254 ha of Los Alamos National Laboratory (LANL) to determine the presence of nesting goshawks on LANL lands. This information can be incorporated into LANL`s environmental management program. The inventory was conducted by Colorado State University personnel from May 12 to July 30, 1993. This report summarizes the results of this inventory.

  12. Final environmental assessment: TRU waste drum staging building, Technical Area 55, Los Alamos National Laboratory

    SciTech Connect

    1996-02-09

    Much of the US Department of Energy`s (DOE`s) research on plutonium metallurgy and plutonium processing is performed at Los Alamos National Laboratory (LANL), in Los Alamos, New Mexico. LANL`s main facility for plutonium research is the Plutonium Facility, also referred to as Technical Area 55 (TA-55). The main laboratory building for plutonium work within the Plutonium Facility (TA-55) is the Plutonium Facility Building 4, or PF-4. This Environmental Assessment (EA) analyzes the potential environmental effects that would be expected to occur if DOE were to stage sealed containers of transuranic (TRU) and TRU mixed waste in a support building at the Plutonium Facility (TA-55) that is adjacent to PF-4. At present, the waste containers are staged in the basement of PF-4. The proposed project is to convert an existing support structure (Building 185), a prefabricated metal building on a concrete foundation, and operate it as a temporary staging facility for sealed containers of solid TRU and TRU mixed waste. The TRU and TRU mixed wastes would be contained in sealed 55-gallon drums and standard waste boxes as they await approval to be transported to TA-54. The containers would then be transported to a longer term TRU waste storage area at TA-54. The TRU wastes are generated from plutonium operations carried out in PF-4. The drum staging building would also be used to store and prepare for use new, empty TRU waste containers.

  13. Optical absorption and radiative heat transport in olivine at high temperature

    NASA Technical Reports Server (NTRS)

    Shankland, T. J.; Nitsan, U.; Duba, A. G.

    1979-01-01

    Results are presented of measurements of the optical absorption spectra (300-8000 nm) of olivine as a function of temperature (300-1700 K) under conditions of controlled and known oxygen fugacity within the stability field of the samples. The absorption spectra are used to calculate the temperature-dependent radiative transfer coefficient of olivine and to numerically study the accuracy of the method. The present absorption measurements in olivine under oxidizing conditions known to be within the olivine stability field indicate that the effective radiative conductivity K(R) is lower than that obtained in previous studies under different experimental conditions. The lower value of K(R) makes it more likely that some of the earth's internal heat is removed by convection and less likely that thermal models involving conduction and radiation alone will satisfactorily explain thermal conditions in the earth's mantle.

  14. A Radiative Transport Model for Heating Paints using High Density Plasma Arc Lamps

    SciTech Connect

    Sabau, Adrian S; Duty, Chad E; Dinwiddie, Ralph Barton; Nichols, Mark; Blue, Craig A; Ott, Ronald D

    2009-01-01

    The energy distribution and ensuing temperature evolution within paint-like systems under the influence of infrared radiation was studied. Thermal radiation effects as well as those due to heat conduction were considered. A complete set of material properties was derived and discussed. Infrared measurements were conducted to obtain experimental data for the temperature in the paint film. The heat flux of the incident radiation from the plasma arc lamp was measured using a heat flux sensor with a very short response time. The comparison between the computed and experimental results for temperature show that the models that are based on spectral four-flux RTE and accurate optical properties yield accurate results for the black paint systems.

  15. Airborne measurements of spectral direct aerosol radiative forcing in the Intercontinental chemical Transport Experiment/Intercontinental Transport and Chemical Transformation of anthropogenic pollution, 2004

    NASA Astrophysics Data System (ADS)

    Redemann, Jens; Pilewskie, Peter; Russell, Philip B.; Livingston, John M.; Howard, Steve; Schmid, Beat; Pommier, John; Gore, Warren; Eilers, James; Wendisch, Manfred

    2006-07-01

    As part of the INTEX-NA (Intercontinental chemical Transport Experiment-North America) and ITCT (Intercontinental Transport and Chemical Transformation of anthropogenic pollution) field studies, the NASA Ames 14-channel Airborne Tracking Sunphotometer (AATS-14) and a pair of Solar Spectral Flux Radiometers (SSFR) took measurements from aboard a Sky Research Jet stream 31 (J31) aircraft during 19 science flights over the Gulf of Maine during 12 July to 8 August 2004. The combination of coincident AATS-14 and SSFR measurements yields plots of net (downwelling minus upwelling) spectral irradiance as a function of aerosol optical depth (AOD) as measured along horizontal flight legs. By definition, the slope of these plots yields the instantaneous change in net irradiance per unit AOD change and is referred to as the instantaneous spectral aerosol radiative forcing efficiency, Ei (W m-2 nm-1). Numerical integration over a given spectral range yields the instantaneous broadband aerosol radiative forcing efficiency (W m-2). This technique for deriving Ei is called the aerosol gradient method. Within 10 case studies considered suitable for our analysis we found a high variability in the derived instantaneous aerosol forcing efficiencies for the visible wavelength range (350-700 nm), with a mean of -79.6 W m-2 and a standard deviation of 21.8 W m-2 (27%). An analytical conversion of the instantaneous forcing efficiencies to 24-hour-average values yielded -45.8 ± 13.1 W m-2 (mean ± std). We present spectrally resolved aerosol forcing efficiencies between 350 and 1670 nm, estimates of the midvisible aerosol single scattering albedo and a comparison of observed broadband forcing efficiencies to previously reported values.

  16. Ballistic phonon and thermal radiation transport across a minute vacuum gap in between aluminum and silicon thin films: Effect of laser repetitive pulses on transport characteristics

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Ali, H.

    2016-08-01

    Short-pulse laser heating of aluminum and silicon thin films pair with presence of a minute vacuum gap in between them is considered and energy transfer across the thin films pair is predicted. The frequency dependent Boltzmann equation is used to predict the phonon intensity distribution along the films pair for three cycles of the repetitive short-pulse laser irradiation on the aluminum film surface. Since the gap size considered is within the Casimir limit, thermal radiation and ballistic phonon contributions to energy transfer across the vacuum gap is incorporated. The laser irradiated field is formulated in line with the Lambert's Beer law and it is considered as the volumetric source in the governing equations of energy transport. In order to assess the phonon intensity distribution in the films pair, equivalent equilibrium temperature is introduced. It is demonstrated that thermal separation of electron and lattice sub-systems in the aluminum film, due to the short-pulse laser irradiation, takes place and electron temperature remains high in the aluminum film while equivalent equilibrium temperature for phonons decays sharply in the close region of the aluminum film interface. This behavior is attributed to the phonon boundary scattering at the interface and the ballistic phonon transfer to the silicon film across the vacuum gap. Energy transfer due to the ballistic phonon contribution is significantly higher than that of the thermal radiation across the vacuum gap.

  17. Development of parallel monte carlo electron and photon transport (PMCEPT) code III: Applications to medical radiation physics

    NASA Astrophysics Data System (ADS)

    Kum, Oyeon; Han, Youngyih; Jeong, Hae Sun

    2012-05-01

    Minimizing the differences between dose distributions calculated at the treatment planning stage and those delivered to the patient is an essential requirement for successful radiotheraphy. Accurate calculation of dose distributions in the treatment planning process is important and can be done only by using a Monte Carlo calculation of particle transport. In this paper, we perform a further validation of our previously developed parallel Monte Carlo electron and photon transport (PMCEPT) code [Kum and Lee, J. Korean Phys. Soc. 47, 716 (2005) and Kim and Kum, J. Korean Phys. Soc. 49, 1640 (2006)] for applications to clinical radiation problems. A linear accelerator, Siemens' Primus 6 MV, was modeled and commissioned. A thorough validation includes both small fields, closely related to the intensity modulated radiation treatment (IMRT), and large fields. Two-dimensional comparisons with film measurements were also performed. The PMCEPT results, in general, agreed well with the measured data within a maximum error of about 2%. However, considering the experimental errors, the PMCEPT results can provide the gold standard of dose distributions for radiotherapy. The computing time was also much faster, compared to that needed for experiments, although it is still a bottleneck for direct applications to the daily routine treatment planning procedure.

  18. Voxel2MCNP: a framework for modeling, simulation and evaluation of radiation transport scenarios for Monte Carlo codes.

    PubMed

    Pölz, Stefan; Laubersheimer, Sven; Eberhardt, Jakob S; Harrendorf, Marco A; Keck, Thomas; Benzler, Andreas; Breustedt, Bastian

    2013-08-21

    The basic idea of Voxel2MCNP is to provide a framework supporting users in modeling radiation transport scenarios using voxel phantoms and other geometric models, generating corresponding input for the Monte Carlo code MCNPX, and evaluating simulation output. Applications at Karlsruhe Institute of Technology are primarily whole and partial body counter calibration and calculation of dose conversion coefficients. A new generic data model describing data related to radiation transport, including phantom and detector geometries and their properties, sources, tallies and materials, has been developed. It is modular and generally independent of the targeted Monte Carlo code. The data model has been implemented as an XML-based file format to facilitate data exchange, and integrated with Voxel2MCNP to provide a common interface for modeling, visualization, and evaluation of data. Also, extensions to allow compatibility with several file formats, such as ENSDF for nuclear structure properties and radioactive decay data, SimpleGeo for solid geometry modeling, ImageJ for voxel lattices, and MCNPX's MCTAL for simulation results have been added. The framework is presented and discussed in this paper and example workflows for body counter calibration and calculation of dose conversion coefficients is given to illustrate its application.

  19. Experimental Study on Fast Electrons Transport in Ultra-intense Laser Irradiated Solid Targets by Transition Radiation

    NASA Astrophysics Data System (ADS)

    Zhijian, Zheng; Guangcan, Wang; Yuqiu, Gu

    2008-11-01

    The experiment was performed with SILEX laser facility(Ti-saphhire) at LFRC in China. The SILEX parameter: wavelength 0.8μm, duration 35fs, output power 280TW, contrast 5*105, The focal spot φ10μm(F/1.7), intensity on target surface 1*10^19W/cm^2(F/3). The main diagnostic equipments are the electron spectrometer, OMA spectrometer, optical streak camera. Some experimental results are given: The spectrum of optical emission from rear surface is rather narrow around some particular frequencies(1φ, 2φ, 3φ), We ascribe and confirm that the spike-like spectral line that is coherent transition radiation; The coherent light is also seen on time-integrated image with ring-patter due to Weibel instability of the fast electron transport; Obtained experimental cure of target thickness vs OTR image intensity is relative to mean free path of fast electron; The measuring optical transition radiation(OTR) duration of 171ps much longer than 1ps duration of fast electron transport target, the possible explanation is that the OTR duration to be determined magnetic diffusion time.

  20. A progress report on UNICOS misuse detection at Los Alamos

    SciTech Connect

    Thompson, J.L.; Jackson, K.A.; Stallings, C.A.; Simmonds, D.D.; Siciliano, C.L.B.; Pedicini, G.A.

    1995-10-01

    An effective method for detecting computer misuse is the automatic monitoring and analysis of on-line user activity. During the past year, Los Alamos enhanced its Network Anomaly Detection and Intrusion Reporter (NADIR) to include analysis of user activity on Los Alamos` UNICOS Crays. In near real-time, NADIR compares user activity to historical profiles and tests activity against expert rules. The expert rules express Los Alamos` security policy and define improper or suspicious behavior. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes the implementation to date of the UNICOS component of NADIR, along with the operational experiences and future plans for the system.

  1. Publications of Los Alamos research, 1977-1981

    SciTech Connect

    Sheridan, C.J.; Garcia, C.A.

    1983-03-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1977-1981. Papers published in those years are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted - even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was published more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-Laboratory reports, journal articles, books, chapters of books, conference papers either published separately or as part of conference proceedings issued as books or reports, papers published in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  2. Water Supply at Los Alamos 1998-2001

    SciTech Connect

    Richard J. Koch; David B. Rogers

    2003-03-01

    For the period 1998 through 2001, the total water used at Los Alamos from all sources ranged from 1325 million gallons (Mg) in 1999 to 1515 Mg in 2000. Groundwater production ranged from 1323 Mg in 1999 to 1506 Mg in 2000 from the Guaje, Pajarito, and Otowi fields. Nonpotable surface water used from Los Alamos reservoir ranged from zero gallons in 2001 to 9.3 Mg in 2000. For years 1998 through 2001, over 99% of all water used at Los Alamos was groundwater. Water use by Los Alamos National Laboratory (LANL) between 1998 and 2001 ranged from 379 Mg in 2000 to 461 Mg in 1998. The LANL water use in 2001 was 393 Mg or 27% of the total water use at Los Alamos. Water use by Los Alamos County ranged from 872 Mg in 1999 to 1137 Mg in 2000, and averaged 1006 Mg/yr. Four new replacement wells in the Guaje field (G-2A, G-3A, G-4A, and G-5A) were drilled in 1998 and began production in 1999; with existing well G-1A, the Guaje field currently has five producing wells. Five of the old Guaje wells (G-1, G-2, G-4, G-5, and G-6) were plugged and abandoned in 1999, and one well (G-3) was abandoned but remains as an observation well for the Guaje field. The long-term water level observations in production and observation (test) wells at Los Alamos are consistent with the formation of a cone of depression in response to water production. The water level decline is gradual and at most has been about 0.7 to 2 ft per year for production wells and from 0.4 to 0.9 ft/yr for observation (test) wells. The largest water level declines have been in the Guaje field where nonpumping water levels were about 91 ft lower in 2001 than in 1951. The initial water levels of the Guaje replacement wells were 32 to 57 ft lower than the initial water levels of adjacent original Guaje wells. When production wells are taken off-line for pump replacement or repair, water levels have returned to within about 25 ft of initial static levels within 6 to 12 months. Thus, the water-level trends suggest no adverse

  3. Sound speed and oscillation frequencies for a solar model evolved with Los Alamos ATOMIC opacities

    NASA Astrophysics Data System (ADS)

    Guzik, Joyce Ann; Fontes, Christopher; Walczak, Przemyslaw; Wood, Suzannah R.; Mussack, Katie

    2015-08-01

    Los Alamos has calculated a new generation of radiative opacities for elements with atomic number Z=1-30 with improved physics input, updated atomic data, and finer temperature grid to replace the Los Alamos LEDCOP opacities released in the year 2000. We calculate the evolution of a standard solar model including these new opacities, and compare with a model evolved using the Lawrence Livermore National Laboratory OPAL opacities released about 1996. We use the solar abundance mixture of Asplund, Grevesse, Sauval, and Scott (2009), including 2015 updates. The Los Alamos ATOMIC opacities (Colgan et al. 2013a,b) are somewhat higher than those of OPAL for temperatures and densities near the base of the solar convection zone. We compare the calculated nonadiabatic solar oscillation frequencies and solar interior sound speed to observed frequencies and helioseismic inferences. We discuss the potential for increased opacities to partially mitigate the ‘solar abundance problem’.References:J. Colgan, D.P. Kilcrease, N.H. Magee, Jr., G.S.J. Armstrong, J. Abdallah, Jr., M.E. Sherrill, C.J. Fontes, H.L. Zhang and P. Hakel, Eighth International Conference on Atomic and Molecular Data and their Applications: ICAMDATA, Gaithersburg, MD 2012, AIP Conf. Proc. No. 1545, (AIP, New York, 2013a), pp. 17-26.J. Colgan, D.P. Kilcrease, N.H. Magee, Jr, G.S.J. Armstrong, J. Abdallah, Jr., M.E. Sherrill, C.J. Fontes, H.L. Zhang and P. Hakel, High Energy Density Physics 9, 369 (2013b).

  4. Low-cost cadmium zinc telluride radiation detectors based on electron-transport-only designs

    SciTech Connect

    B. A. Brunett; J. C. Lund; J. M. Van Scyoc; N. R. Hilton; E. Y. Lee; R. B. James

    1999-01-01

    The goal of this project was to utilize a novel device design to build a compact, high resolution, room temperature operated semiconductor gamma ray sensor. This sensor was constructed from a cadmium zinc telluride (CZT) crystal. It was able to both detect total radiation intensity and perform spectroscopy on the detected radiation. CZT detectors produced today have excellent electron charge carrier collection, but suffer from poor hole collection. For conventional gamma-ray spectrometers, both the electrons and holes must be collected with high efficiency to preserve energy resolution. The requirement to collect the hole carriers, which have relatively low lifetimes, limits the efficiency and performance of existing experimental devices. By implementing novel device designs such that the devices rely only on the electron signal for energy information, the sensitivity of the sensors for detecting radiation can be increased substantially. In this report the authors describe a project to develop a new type of electron-only CZT detector. They report on their successful efforts to design, implement and test these new radiation detectors. In addition to the design and construction of the sensors the authors also report, in considerable detail, on the electrical characteristics of the CZT crystals used to make their detectors.

  5. The Air Transport of Radiation (ATR) Code: Development and Testing of ATR5

    DTIC Science & Technology

    1990-01-02

    Cod( for Computing Fission Product Gamma Dose and Dose Rates," RRA-N7236 (October 1972). 42. F.R. Mynatt , et mi., "Calculations of the Penetration of...penetration of missile silos. Works such 24), and incorporated a method for estimating the contribution of debris radiation to the total. as that by Mynatt , et

  6. Use of single scatter electron monte carlo transport for medical radiation sciences

    DOEpatents

    Svatos, Michelle M.

    2001-01-01

    The single scatter Monte Carlo code CREEP models precise microscopic interactions of electrons with matter to enhance physical understanding of radiation sciences. It is designed to simulate electrons in any medium, including materials important for biological studies. It simulates each interaction individually by sampling from a library which contains accurate information over a broad range of energies.

  7. Water supply at Los Alamos during 1993. Progress report

    SciTech Connect

    Purtymun, W.D.; Stoker, A.K.; McLin, S.G.; Maes, M.N.; Glasco, T.A.

    1995-10-01

    This report summarizes production and aquifer conditions for water wells in the Guaje, Pajarito, and Otowi Well Fields. These wells supplied all of the potable water used for municipal and some industrial purposes in Los Alamos County and the Los Alamos National Laboratory during 1993. The wells in the Los Alamos Well Field were transferred to San Ildefonso Pueblo in 1992. Four of the wells in the Los Alamos Well Field were plugged in 1993. One of the two new wells in the Otowi Well Field became operational in 1993. The spring gallery in Water Canyon supplied nonpotable water for industrial use, while surface water from the Los Alamos Reservoir was diverted for irrigation. In 1993 no water was used from the Guaje Reservoir. Due to the maintenance and operating cost of diverting water from the reservoirs, it is not economically feasible to continue their use for irrigation. This report fulfills some of the requirements of the Los Alamos Groundwater Protection Management Program by documenting use of the groundwater for water supply and providing information hydrologic characteristics of the main aquifer. This report is a joint effort between the Laboratory Water Quality and Hydrology Group and the Utilities Department of Johnson Controls World Services Inc. (JCI). The purpose of this report is to ensure a continuing historical record and to provide guidance for management of water resources in long-range planning for the water supply system. We have issued one summary report for the period of 1947 to 1971 and 22 annual reports that contain the results of our studies of these water supplies. An additional report summarized the hydrology of the main aquifer with reference to future development of groundwater supplies. A report was issued in 1988 that examined the status of wells and future water supply.

  8. Highly Relativistic Radiation Belt Electron Acceleration, Transport, and Loss: Large Solar Storm Events of March and June 2015

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Jaynes, A. N.; Kanekal, S. G.; Foster, J.C.; Erickson, P. J.; Fennell, Joseph; Blake, J. B.; Zhao, H.; Li, X.; Elkington, S. R.; Henderson, M. G.; Reeves, G.; Spence, H.; Kletzing, C. A.; Wygant, J. R.

    2016-01-01

    Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (Disturbance Storm Time Ring Current Index) value reaching 223 nanoteslas. On 22 June 2015 another strong storm (Dst reaching 204 nanoteslas) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E (Energy) greater than or approximately equal to 1 millielectronvolt) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 millielectronvolts in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong butterfly distributions with deep minima in flux at alpha equals 90 degrees. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported impenetrable barrier at L (L-shell magnetic field line value) approximately equal to 2.8 was pushed inward, but not significantly breached, and no E (Energy) greater than or approximately equal to 2.0 millielectronvolts electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.

  9. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    NASA Astrophysics Data System (ADS)

    Kulisek, J. A.; Schweppe, J. E.; Stave, S. C.; Bernacki, B. E.; Jordan, D. V.; Stewart, T. N.; Seifert, C. E.; Kernan, W. J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments.

  10. Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015

    DOE PAGES

    Baker, Daniel N.; Jaynes, A. N.; Kanekal, S. G.; ...

    2016-07-01

    Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching –223 nT. On 22 June 2015 another strong storm (Dst reaching –204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed amore » rich variety of pitch angle features including strong “butterfly” distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported “impenetrable barrier” at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Altogether, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.« less

  11. Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015

    PubMed Central

    Jaynes, A. N.; Kanekal, S. G.; Foster, J. C.; Erickson, P. J.; Fennell, J. F.; Blake, J. B.; Zhao, H.; Li, X.; Elkington, S. R.; Henderson, M. G.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.; Wygant, J. R.

    2016-01-01

    Abstract Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection‐driven event occurred with a Dst (storm time ring current index) value reaching −223 nT. On 22 June 2015 another strong storm (Dst reaching −204 nT) was recorded. These two storms each produced almost total loss of radiation belt high‐energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong “butterfly” distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported “impenetrable barrier” at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis. PMID:27867796

  12. Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015

    SciTech Connect

    Baker, Daniel N.; Jaynes, A. N.; Kanekal, S. G.; Foster, J. C.; Erickson, P. J.; Fennell, J. F.; Blake, J. B.; Zhao, H.; Li, X.; Elkington, S. R.; Henderson, Michael Gerard; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.; Wygant, J. R.

    2016-07-01

    Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching –223 nT. On 22 June 2015 another strong storm (Dst reaching –204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong “butterfly” distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported “impenetrable barrier” at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Altogether, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.

  13. Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015.

    PubMed

    Baker, D N; Jaynes, A N; Kanekal, S G; Foster, J C; Erickson, P J; Fennell, J F; Blake, J B; Zhao, H; Li, X; Elkington, S R; Henderson, M G; Reeves, G D; Spence, H E; Kletzing, C A; Wygant, J R

    2016-07-01

    Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm (Dst reaching -204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong "butterfly" distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported "impenetrable barrier" at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.

  14. Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015

    NASA Astrophysics Data System (ADS)

    Baker, D. N.; Jaynes, A. N.; Kanekal, S. G.; Foster, J. C.; Erickson, P. J.; Fennell, J. F.; Blake, J. B.; Zhao, H.; Li, X.; Elkington, S. R.; Henderson, M. G.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.; Wygant, J. R.

    2016-07-01

    Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm (Dst reaching -204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong "butterfly" distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported "impenetrable barrier" at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.

  15. High Altitude Radiations Relevant to the High Speed Civil Transport (HSCT)

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Goldhagan, P.; Maiden, D. L.; Tai, H.

    2004-01-01

    The Langley Research Center (LaRC) performed atmospheric radiation studies under the SST development program in which important ionizing radiation components were measured and extended by calculations to develop the existing atmospheric ionizing radiation (AIR) model. In that program the measured neutron spectrum was limited to less than 10 MeV by the available 1960-1970 instrumentation. Extension of the neutron spectrum to high energies was made using the LaRC PROPER-3C monte carlo code. It was found that the atmospheric neutrons contributed about half of the dose equivalent and approximately half of the neutron contribution was from high energy neutrons above 10 MeV. Furthermore, monte carlo calculations of solar particle events showed that potential exposures as large as 10-100 mSv/hr may occur on important high latitude routes but acceptable levels of exposure could be obtained if timely descent to subsonic altitudes could be made. The principal concern was for pregnant occupants onboard the aircraft. As a result of these studies the FAA Advisory Committee on the Radiobiological Aspects of the SST recommended: 1. Crew members will have to be informed of their exposure levels 2. Maximum exposures on any flight to be limited to 5 mSv 3. Airborne radiation detection devices for total exposure and exposure rates 4. Satellite monitoring system to provide SST aircraft real-time information on atmospheric radiation levels for exposure mitigation 5. A solar forecasting system to warn flight operations of an impending solar event for flight scheduling and alert status. These recommendations are a reasonable starting point to requirements for the HSCT with some modification reflecting new standards of protection as a result of changing risk coefficients.

  16. A physicists guide to The Los Alamos Primer

    NASA Astrophysics Data System (ADS)

    Reed, B. Cameron

    2016-11-01

    In April 1943, a group of scientists at the newly established Los Alamos Laboratory were given a series of lectures by Robert Serber on what was then known of the physics and engineering issues involved in developing fission bombs. Serber’s lectures were recorded in a 24 page report titled The Los Alamos Primer, which was subsequently declassified and published in book form. This paper describes the background to the Primer and analyzes the physics contained in its 22 sections. The motivation for this paper is to provide a firm foundation of the background and contents of the Primer for physicists interested in the Manhattan Project and nuclear weapons.

  17. Fifty-one years of Los Alamos Spacecraft

    SciTech Connect

    Fenimore, Edward E.

    2014-09-04

    From 1963 to 2014, the Los Alamos National Laboratory was involved in at least 233 spacecraft. There are probably only one or two institutions in the world that have been involved in so many spacecraft. Los Alamos space exploration started with the Vela satellites for nuclear test detection, but soon expanded to ionospheric research (mostly barium releases), radioisotope thermoelectric generators, solar physics, solar wind, magnetospheres, astrophysics, national security, planetary physics, earth resources, radio propagation in the ionosphere, and cubesats. Here, we present a list of the spacecraft, their purpose, and their launch dates for use during RocketFest

  18. Los Alamos Using Neutrons to Stop Nuclear Smugglers

    ScienceCinema

    Favalli, Andrea; Swinhoe, Martyn

    2016-07-12

    Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

  19. Los Alamos Using Neutrons to Stop Nuclear Smugglers

    SciTech Connect

    Favalli, Andrea; Swinhoe, Martyn

    2013-06-03

    Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

  20. The development of the atomic bomb, Los Alamos

    SciTech Connect

    Seidel, R.W.

    1993-11-01

    The historical presentation begins with details of the selection of Los Alamos as the site of the Army installation. Wartime efforts of the Army Corps of Engineers, and scientists to include the leader of Los Alamos, Robert Oppenheimer are presented. The layout and construction of the facilities are discussed. The monumental design requirements of the bombs are discussed, including but not limited to the utilization of the second choice implosion method of detonation, and the production of bomb-grade nuclear explosives. The paper ends with a philosophical discussion on the use of nuclear weapons.

  1. NA22 Model Cities Project - LL244T An Intelligent Transportation System-Based Radiation Alert and Detection System

    SciTech Connect

    Peglow, S

    2004-02-24

    The purpose of this project was twofold: first, provide an understanding of the technical foundation and planning required for deployment of Intelligent Transportation System (ITS)-based system architectures for the protection of New York City from a terrorist attack using a vehicle-deployed nuclear device; second, work with stakeholders to develop mutual understanding of the technologies and tactics required for threat detection/identification and establish guidelines for designing operational systems and procedures. During the course of this project we interviewed and coordinated analysis with people from the New Jersey State Attorney General's office, the New Jersey State Police, the Port Authority of New York/New Jersey, the Counterterrorism Division of the New York City Police Department, the New Jersey Transit Authority, the State of New Jersey Department of Transportation, TRANSCOM and a number of contractors involved with state and federal intelligent transportation development and implementation. The basic system architecture is shown in the figure below. In an actual system deployment, radiation sensors would be co-located with existing ITS elements and the data will be sent to the Traffic Operations Center. A key element of successful system operation is the integration of vehicle data, such as license plate, EZ pass ID, vehicle type/color and radiation signature. A threat data base can also be implemented and utilized in cases where there is a suspect vehicle identified from other intelligence sources or a mobile detector system. Another key aspect of an operational architecture is the procedures used to verify the threat and plan interdiction. This was a major focus of our work and discussed later in detail. In support of the operational analysis, we developed a detailed traffic simulation model that is described extensively in the body of the report.

  2. Needs assessment for fire department services and resources for the Los Alamos National Laboratory, Los Alamos, New Mexico. Final report

    SciTech Connect

    1995-11-15

    This report has been developed in response to a request from the Los Alamos National Laboratory (LANL) to evaluate the need for fire department services so as to enable the Laboratory to plan effective fire protection and thereby: meet LANL`s regulatory and contractual obligations; interface with the Department of Energy (DOE) and other agencies on matters relating to fire and emergency services; and ensure appropriate protection of the community and environment. This study is an outgrowth of the 1993 Fire Department Needs Assessment (prepared for DOE) but is developed from the LANL perspective. Input has been received from cognizant and responsible representatives at LANL, DOE, Los Alamos County (LAC) and the Los Alamos Fire Department (LAFD).

  3. Structural testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

    SciTech Connect

    Bronowski, D.R.; Madsen, M.M.

    1991-06-01

    The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in three orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.

  4. Emission, transport, and radiative effects of mineral dust from the Taklimakan and Gobi deserts: comparison of measurements and model results

    NASA Astrophysics Data System (ADS)

    Chen, Siyu; Huang, Jianping; Kang, Litai; Wang, Hao; Ma, Xiaojun; He, Yongli; Yuan, Tiangang; Yang, Ben; Huang, Zhongwei; Zhang, Guolong

    2017-02-01

    The Weather Research and Forecasting Model with chemistry (WRF-Chem model) was used to investigate a typical dust storm event that occurred from 18 to 23 March 2010 and swept across almost all of China, Japan, and Korea. The spatial and temporal variations in dust aerosols and the meteorological conditions over East Asia were well reproduced by the WRF-Chem model. The simulation results were used to further investigate the details of processes related to dust emission, long-range transport, and radiative effects of dust aerosols over the Taklimakan Desert (TD) and Gobi Desert (GD). The results indicated that weather conditions, topography, and surface types in dust source regions may influence dust emission, uplift height, and transport at the regional scale. The GD was located in the warm zone in advance of the cold front in this case. Rapidly warming surface temperatures and cold air advection at high levels caused strong instability in the atmosphere, which strengthened the downward momentum transported from the middle and low troposphere and caused strong surface winds. Moreover, the GD is located in a relatively flat, high-altitude region influenced by the confluence of the northern and southern westerly jets. Therefore, the GD dust particles were easily lofted to 4 km and were the primary contributor to the dust concentration over East Asia. In the dust budget analysis, the dust emission flux over the TD was 27.2 ± 4.1 µg m-2 s-1, which was similar to that over the GD (29 ± 3.6 µg m-2 s-1). However, the transport contribution of the TD dust (up to 0.8 ton d-1) to the dust sink was much smaller than that of the GD dust (up to 3.7 ton d-1) because of the complex terrain and the prevailing wind in the TD. Notably, a small amount of the TD dust (PM2.5 dust concentration of approximately 8.7 µg m-3) was lofted to above 5 km and transported over greater distances under the influence of the westerly jets. Moreover, the direct radiative forcing induced by dust

  5. Geological site characterization for the proposed Mixed Waste Disposal Facility, Los Alamos National Laboratory

    SciTech Connect

    Reneau, S.L.; Raymond, R. Jr.

    1995-12-01

    This report presents the results of geological site characterization studies conducted from 1992 to 1994 on Pajarito Mesa for a proposed Los Alamos National Laboratory Mixed Waste Disposal Facility (MWDF). The MWDF is being designed to receive mixed waste (waste containing both hazardous and radioactive components) generated during Environmental Restoration Project cleanup activities at Los Alamos. As of 1995, there is no Resource Conservation and Recovery Act (RCRA) permitted disposal site for mixed waste at the Laboratory, and construction of the MWDF would provide an alternative to transport of this material to an off-site location. A 2.5 km long part of Pajarito Mesa was originally considered for the MWDF, extending from an elevation of about 2150 to 2225 m (7060 to 7300 ft) in Technical Areas (TAs) 15, 36, and 67 in the central part of the Laboratory, and planning was later concentrated on the western area in TA-67. The mesa top lies about 60 to 75 m (200 to 250 ft) above the floor of Pajarito Canyon on the north, and about 30 m (100 ft) above the floor of Threemile Canyon on the south. The main aquifer used as a water supply for the Laboratory and for Los Alamos County lies at an estimated depth of about 335 m (1100 ft) below the mesa. The chapters of this report focus on surface and near-surface geological studies that provide a basic framework for siting of the MWDF and for conducting future performance assessments, including fulfillment of specific regulatory requirements. This work includes detailed studies of the stratigraphy, mineralogy, and chemistry of the bedrock at Pajarito Mesa by Broxton and others, studies of the geological structure and of mesa-top soils and surficial deposits by Reneau and others, geologic mapping and studies of fracture characteristics by Vaniman and Chipera, and studies of potential landsliding and rockfall along the mesa-edge by Reneau.

  6. Environmental Assessment for Proposed Access Control and Traffic Improvements at Los Alamos National Laboratory, Los Alamos, New Mexico

    SciTech Connect

    N /A

    2002-08-23

    The National Nuclear Security Administration (NNSA) has assigned a continuing role to Los Alamos National Laboratory (LANL) in carrying out NNSA's national security mission. It is imperative that LANL continue this enduring responsibility and that NNSA adequately safeguard LANL capabilities. NNSA has identified the need to restrict vehicular access to certain areas within LANL for the purpose of permanently enhancing the physical security environment at LANL. It has also identified the need to change certain traffic flow patterns for the purpose of enhancing physical safety at LANL. The Proposed Action would include the construction of eastern and western bypass roads around the LANL Technical Area (TA) 3 area and the installation of vehicle access controls and related improvements to enhance security along Pajarito Road and in the LANL core area. This Proposed Action would modify the current roadway network and traffic patterns. It would also result in traversing Areas of Environmental Interest identified in the LANL Habitat Management Plan, demolition of part of an historic structure at Building 3-40, and traversing several potential release sites and part of the Los Alamos County landfill. The No Action Alternative was also considered. Under this alternative NNSA would not construct the eastern or western bypass roads, any access-control stations, or related improvements. Diamond Drive would continue to serve as the primary conduit for most vehicle traffic within the LANL core area regardless of actual trip destinations. The No Action Alternative does not meet NNSA's purpose and need for action. The proposed bypass road corridors traverse both developed and undeveloped areas. Several potential release sites are present. These would either be sampled and remediated in accordance with New Mexico Environment Department requirements before construction or avoided to allow for future remediation. In some cases, contaminant levels may fall below remediation thresholds

  7. Radiation and gas conduction heat transport across a helium dewer multilayer insulation system

    SciTech Connect

    Green, M.A.

    1995-02-01

    This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulated a 4K liquid helium cryostat. The method described permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.

  8. Radiation and gas conduction heat transport across a helium dewar multilayer insulation system

    SciTech Connect

    Green, M.A.

    1994-10-10

    This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulate a 4 K liquid helium cryostat. The method described here permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.

  9. Voxel2MCNP: software for handling voxel models for Monte Carlo radiation transport calculations.

    PubMed

    Hegenbart, Lars; Pölz, Stefan; Benzler, Andreas; Urban, Manfred

    2012-02-01

    Voxel2MCNP is a program that sets up radiation protection scenarios with voxel models and generates corresponding input files for the Monte Carlo code MCNPX. Its technology is based on object-oriented programming, and the development is platform-independent. It has a user-friendly graphical interface including a two- and three-dimensional viewer. A row of equipment models is implemented in the program. Various voxel model file formats are supported. Applications include calculation of counting efficiency of in vivo measurement scenarios and calculation of dose coefficients for internal and external radiation scenarios. Moreover, anthropometric parameters of voxel models, for instance chest wall thickness, can be determined. Voxel2MCNP offers several methods for voxel model manipulations including image registration techniques. The authors demonstrate the validity of the program results and provide references for previous successful implementations. The authors illustrate the reliability of calculated dose conversion factors and specific absorbed fractions. Voxel2MCNP is used on a regular basis to generate virtual radiation protection scenarios at Karlsruhe Institute of Technology while further improvements and developments are ongoing.

  10. A survey of macromycete diversity at Los Alamos National Laboratory, Bandelier National Monument, and Los Alamos County; A preliminary report

    SciTech Connect

    Jarmie, N.; Rogers, F.J.

    1997-11-01

    The authors have completed a 5-year survey (1991--1995) of macromycetes found in Los Alamos County, Los Alamos National Laboratory, and Bandelier National Monument. The authors have compiled a database of 1,048 collections, their characteristics, and identifications. The database represents 123 (98%) genera and 175 (73%) species reliably identified. Issues of habitat loss, species extinction, and ecological relationships are addressed, and comparisons with other surveys are made. With this baseline information and modeling of this baseline data, one can begin to understand more about the fungal flora of the area.

  11. Working with Fermi at Chicago and Los Alamos

    NASA Astrophysics Data System (ADS)

    Garwin, Richard L.

    2010-02-01

    I discuss my experience with Enrico Fermi as student and fellow faculty member at Chicago and with him as consultants to the Los Alamos Scientific Laboratory in 1950-1952. The talk shares observations about this great physicist and exemplary human being. )

  12. The Controlled-Air Incinerator at Los Alamos

    SciTech Connect

    Newmyer, J.N.

    1994-04-01

    The Controlled-Air Incinerator (CAI) at Los Alamos is being modified and upgraded to begin routine operations treating low-level mixed waste (LLMW), radioactively contaminated polychlorinated biphenyl (PCB) wastes, low-level liquid wastes, and possibly transuranic (TRU) wastes. This paper describes those modifications. Routine waste operations should begin in late FY95.

  13. Mercury: The Los Alamos ICF KrF laser system

    SciTech Connect

    Czuchlewski, S.J.; York, G.W.; Bigio, I.J.; Brucker, J.; Hanson, D.; Honig, E.M.; Kurnit, N.; Leland, W.; McCown, A.W.; McLeod, J.; Rose, E.; Thomas, S.; Thompson, D.

    1993-01-19

    The Mercury KrF laser facility at Los Alamos is being built with the benefit of lessons learned from the Aurora system. An increased understanding of KrF laser engineering, and the designed implementation of system flexibility, will permit Mercury to serve as a tested for a variety of advanced KrF technology concepts.

  14. The Los Alamos nuclear safeguards and nonproliferation technology development program

    SciTech Connect

    Smith, H.A. Jr.; Menlove, H.O.; Reilly, T.D.; Bosler, G.E.; Hakkila, E.A.; Eccleston, G.W.

    1994-04-01

    For nearly three decades, Los Alamos National Laboratory has developed and implemented nuclear measurement technology and training in support of national and international nuclear safeguards. This paper outlines the major elements of those technologies and highlights some of the latest developments.

  15. Plasma and ion beam processing at Los Alamos

    SciTech Connect

    Rej, D.J.; Davis, H.A.; Henins, I.

    1994-07-01

    Efforts are underway at Los Alamos National Laboratory to utilize plasma and intense ion beam science and technology of the processing of advanced materials. A major theme involves surface modification of materials, e.g., etching, deposition, alloying, and implantation. In this paper, we concentrate on two programs, plasma source ion implantation and high-intensity pulsed ion beam deposition.

  16. [Los Alamos National Laboratory industrial applications and technology transfer

    SciTech Connect

    Not Available

    1992-09-30

    In October 1989, the Los Alamos Economic Development Corporation (LAEDC) entered into a contract with the Industrial Applications office (IAO) of Los Alamos National Laboratory (LANL) whereby the LAEDC was to provide support services to IAO. More specifically, according to the Statement of Work in this contract The Los Alamos Economic Development Corporation shall assist the Los Alamos National Laboratory Industrial Applications Office in establishing and strengthening connections between potential entrepreneurs at the Laboratory and the business assistance community throughout New Mexico, directed toward enhancing the number, of successful start up businesses spinning off the Laboratory's technology base.'' As part of this contract and subsequent modifications thereof, the LAEDC was to perform seven tasks: 1. Provide business planning assistance to potential entrepreneurs. 2. (Assist IAO in preparing and distributing) informational materials on technology transfer. 3. (Organize and manage) meetings and seminars on technology transfer and entrepreneurship. 4. Identify new opportunities for technology transfer. 5. (Identify and implement programs for the) recognition of Laboratory Entrepreneurs. 6. Training Lab personnel, in the area of technology transfer and Laboratory industrial interactions. 7. Review and summarize prior New Mexico economic development studies. The purpose of this report, is to summarize the accomplishments of the LAEDC under its contract with IAO, and to fulfill its reporting requirements. This report covers the period from October 1989 to September 1992.

  17. Aqueous Nitrate Recovery Line at Los Alamos National Laboratory

    SciTech Connect

    Finstad, Casey Charles

    2016-06-15

    This powerpoint is part of the ADPSM Plutonium Engineering Lecture Series, which is an opportunity for new hires at LANL to get an overview of work done at TA55. It goes into detail about the aqueous nitrate recovery line at Los Alamos National Laboratory.

  18. Brief review of Rover fuel development at Los Alamos

    NASA Technical Reports Server (NTRS)

    Davidson, Keith V.

    1991-01-01

    A brief review of the graphite matrix uranium fuel development efforts at Los Alamos from 1955 through 1972 is presented. The uses of graphite flour carbon black, various binders, uranium dioxide, coated UC2 particles, and zirconium carbide in this development are described.

  19. Airport-Noise Levels and Annoyance Model (ALAMO) system's reference manual

    NASA Technical Reports Server (NTRS)

    Deloach, R.; Donaldson, J. L.; Johnson, M. J.

    1986-01-01

    The airport-noise levels and annoyance model (ALAMO) is described in terms of the constituent modules, the execution of ALAMO procedure files, necessary for system execution, and the source code documentation associated with code development at Langley Research Center. The modules constituting ALAMO are presented both in flow graph form, and through a description of the subroutines and functions that comprise them.

  20. HZETRN: A heavy ion/nucleon transport code for space radiations

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Chun, Sang Y.; Badavi, Forooz F.; Townsend, Lawrence W.; Lamkin, Stanley L.

    1991-01-01

    The galactic heavy ion transport code (GCRTRN) and the nucleon transport code (BRYNTRN) are integrated into a code package (HZETRN). The code package is computer efficient and capable of operating in an engineering design environment for manned deep space mission studies. The nuclear data set used by the code is discussed including current limitations. Although the heavy ion nuclear cross sections are assumed constant, the nucleon-nuclear cross sections of BRYNTRN with full energy dependence are used. The relation of the final code to the Boltzmann equation is discussed in the context of simplifying assumptions. Error generation and propagation is discussed, and comparison is made with simplified analytic solutions to test numerical accuracy of the final results. A brief discussion of biological issues and their impact on fundamental developments in shielding technology is given.

  1. Solutions and reductions for radiative energy transport in laser-heated plasma

    SciTech Connect

    Broadbridge, P.; Ivanova, N. M.

    2015-01-15

    A full symmetry classification is given for models of energy transport in radiant plasma when the mass density is spatially variable and the diffusivity is nonlinear. A systematic search for conservation laws also leads to some potential symmetries and to an integrable nonlinear model. Classical point symmetries, potential symmetries, and nonclassical symmetries are used to effect variable reductions and exact solutions. The simplest time-dependent solution is shown to be stable and relevant to a closed system.

  2. Transport Imaging: Developing an Optical Technique to Characterize Bulk Semiconductor Materials for Next Generation Radiation Detectors

    DTIC Science & Technology

    2009-06-01

    OF PAGES 79 14. SUBJECT TERMS Cathodoluminescence, Diffusion , Drift, Mobility, Lifetime, Bismuth Ferrite , BiFeO3 , Semiconductor, Transport...migrate or diffuse from a region of high concentration to low concentration. The diffusion coefficient (D) quantifies the diffusivity of a material...The diffusion coefficient is found using the Einstein relation kTD e μ = where k is Boltzmann’s constant, T is the temperature, e is the charge

  3. Contaminant signature at Los Alamos firing sites

    SciTech Connect

    Becker, N.; Irvine, J.

    1996-01-01

    During a dynamic weapons test, a weapons component is either explosively detonated or impacted against a target in the open air environment. This results in both the production of a wide size range of depleted uranium particles as well as particle scattering over a considerable distance away from the firing pad. The explosive detonation process which creates aerial distribution over a watershed distinguishes this contaminant transport problem from others where the source term is spatially discrete. Investigations of this contamination began in 1983 with collection of onsite soils, sediments, and rock samples to establish uranium concentrations. The samples were analyzed for total uranium to evaluate the magnitude of transport of uranium away from firing sites by airborne and surface water runoff mechanisms. This data was then used to define a firing site.

  4. A fast Monte Carlo code for proton transport in radiation therapy based on MCNPX.

    PubMed

    Jabbari, Keyvan; Seuntjens, Jan

    2014-07-01

    An important requirement for proton therapy is a software for dose calculation. Monte Carlo is the most accurate method for dose calculation, but it is very slow. In this work, a method is developed to improve the speed of dose calculation. The method is based on pre-generated tracks for particle transport. The MCNPX code has been used for generation of tracks. A set of data including the track of the particle was produced in each particular material (water, air, lung tissue, bone, and soft tissue). This code can transport protons in wide range of energies (up to 200 MeV for proton). The validity of the fast Monte Carlo (MC) code is evaluated with data MCNPX as a reference code. While analytical pencil beam algorithm transport shows great errors (up to 10%) near small high density heterogeneities, there was less than 2% deviation of MCNPX results in our dose calculation and isodose distribution. In terms of speed, the code runs 200 times faster than MCNPX. In the Fast MC code which is developed in this work, it takes the system less than 2 minutes to calculate dose for 10(6) particles in an Intel Core 2 Duo 2.66 GHZ desktop computer.

  5. A fast Monte Carlo code for proton transport in radiation therapy based on MCNPX

    PubMed Central

    Jabbari, Keyvan; Seuntjens, Jan

    2014-01-01

    An important requirement for proton therapy is a software for dose calculation. Monte Carlo is the most accurate method for dose calculation, but it is very slow. In this work, a method is developed to improve the speed of dose calculation. The method is based on pre-generated tracks for particle transport. The MCNPX code has been used for generation of tracks. A set of data including the track of the particle was produced in each particular material (water, air, lung tissue, bone, and soft tissue). This code can transport protons in wide range of energies (up to 200 MeV for proton). The validity of the fast Monte Carlo (MC) code is evaluated with data MCNPX as a reference code. While analytical pencil beam algorithm transport shows great errors (up to 10%) near small high density heterogeneities, there was less than 2% deviation of MCNPX results in our dose calculation and isodose distribution. In terms of speed, the code runs 200 times faster than MCNPX. In the Fast MC code which is developed in this work, it takes the system less than 2 minutes to calculate dose for 106 particles in an Intel Core 2 Duo 2.66 GHZ desktop computer. PMID:25190994

  6. Transport simulations of a density limit in radiation-dominated tokamak discharges: II

    SciTech Connect

    Stotler, D.P.

    1991-05-01

    The procedures developed previously to simulate the radiatively induced tokamak density limit are used to examine in more detail the scaling of the density limit. It is found that the maximum allowable density increases with auxiliary power and decreases with impurity concentration. However, it is demonstrated that there is little dependence of the density limit on plasma elongation. These trends are consistent with experimental results. Our previous work used coronal equilibrium impurities; the primary result of that paper was that the maximum density increases with current when peaked profiles are assumed. Here, this behavior is shown to occur with a coronal nonequilibrium impurity as well. 26 refs., 4 figs.

  7. Influence of Natural Convection and Thermal Radiation Multi-Component Transport in MOCVD Reactors

    NASA Technical Reports Server (NTRS)

    Lowry, S.; Krishnan, A.; Clark, I.

    1999-01-01

    The influence of Grashof and Reynolds number in Metal Organic Chemical Vapor (MOCVD) reactors is being investigated under a combined empirical/numerical study. As part of that research, the deposition of Indium Phosphide in an MOCVD reactor is modeled using the computational code CFD-ACE. The model includes the effects of convection, conduction, and radiation as well as multi-component diffusion and multi-step surface/gas phase chemistry. The results of the prediction are compared with experimental data for a commercial reactor and analyzed with respect to the model accuracy.

  8. Radiation Doses to the Public From the Transport of Spent Nuclear Fuel

    SciTech Connect

    Best, R. E.; Maheras, S. J.; Ross, S. S.; Weiner, R.

    2003-02-25

    This paper reviews issues that have been raised concerning radiological risks and safety of the public exposed to shipments of spent nuclear fuel and high-level radioactive waste to a Yucca Mountain repository. It presents and analyzes the contrasting viewpoints of opponents and proponents, presents facts about radiological exposures and risks, and provides perspective from which to observe the degree of risk that would devolve from the shipments. The paper concludes that the risks to the public's health and safety from being exposed to radiation from the shipments will not be discernable.

  9. An Evaluation of Mass Integral Scaling as Applied to the Atmospheric Radiation Transport Problem

    DTIC Science & Technology

    1976-11-01

    Air/GroundInterface Effects o.i Fast- Neutron Distributions ." Nucl. Sci. Enq.,19: 151-157 (1964). 15. Zerby, C. D. Radiation Flux Transformation as a...31, 37/21 coupled neutron and gamma, multigroup energy structure (Ref. 20) shown in Table II, the silicon and tissue response functions shown in...Monte Ca.blo Calculation. KN-774-69-1. Colorado Sprinas, CO: Kaman Sciences Corp., January )969. 8. Raso, D. J. " Neutron Energy Flux in an Exponential

  10. Environmental assessment for effluent reduction, Los Alamos National Laboratory, Los Alamos, New Mexico

    SciTech Connect

    1996-09-11

    The Department of Energy (DOE) proposes to eliminate industrial effluent from 27 outfalls at Los Alamos National Laboratory (LANL). The Proposed Action includes both simple and extensive plumbing modifications, which would result in the elimination of industrial effluent being released to the environment through 27 outfalls. The industrial effluent currently going to about half of the 27 outfalls under consideration would be rerouted to LANL`s sanitary sewer system. Industrial effluent from other outfalls would be eliminated by replacing once-through cooling water systems with recirculation systems, or, in a few instances, operational changes would result in no generation of industrial effluent. After the industrial effluents have been discontinued, the affected outfalls would be removed from the NPDES Permit. The pipes from the source building or structure to the discharge point for the outfalls may be plugged, or excavated and removed. Other outfalls would remain intact and would continue to discharge stormwater. The No Action alternative, which would maintain the status quo for LANL`s outfalls, was also analyzed. An alternative in which industrial effluent would be treated at the source facilities was considered but dismissed from further analysis because it would not reasonably meet the DOE`s purpose for action, and its potential environmental effects were bounded by the analysis of the Proposed Action and the No Action alternatives.

  11. Environmental Survey preliminary report, Los Alamos National Laboratory, Los Alamos, New Mexico

    SciTech Connect

    Not Available

    1988-01-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy's (DOE) Los Alamos National Laboratory (LANL), conducted March 29, 1987 through April 17, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are outside experts being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the LANL. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at the LANL, and interviews with site personnel. The Survey team developed Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by the Idaho National Engineering Laboratory. When completed, the results will be incorporated into the LANL Environmental Survey Interim Report. The Interim Report will reflect the final determinations of the Survey for the LANL. 65 refs., 68 figs., 73 tabs.

  12. Los Alamos National Laboratory transuranic waste quality assurance project plan. Revision 1

    SciTech Connect

    1997-04-14

    This Transuranic (TRU) Waste Quality Assurance Project Plan (QAPjP) serves as the quality management plan for the characterization of transuranic waste in preparation for certification and transportation. The Transuranic Waste Characterization/Certification Program (TWCP) consists of personnel who sample and analyze waste, validate and report data; and provide project management, quality assurance, audit and assessment, and records management support, all in accordance with established requirements for disposal of TRU waste at the Waste Isolation Pilot Plant (WIPP) facility. This QAPjP addresses how the TWCP meets the quality requirements of the Carlsbad Area Office (CAO) Quality Assurance Program Description (QAPD) and the technical requirements of the Transuranic Waste Characterization Quality Assurance Program Plan (QAPP). The TWCP characterizes and certifies retrievably stored and newly generated TRU waste using the waste selection, testing, sampling, and analytical techniques and data quality objectives (DQOs) described in the QAPP, the Los Alamos National Laboratory Transuranic Waste Certification Plan (Certification Plan), and the CST Waste Management Facilities Waste Acceptance Criteria and Certification [Los Alamos National Laboratory (LANL) Waste Acceptance Criteria (WAC)]. At the present, the TWCP does not address remote-handled (RH) waste.

  13. Energy supply and environmental issues: The Los Alamos National Laboratory experience in regional and international programs

    SciTech Connect

    Goff, S.J.

    1995-12-31

    The Los Alamos National Laboratory, operated by the University of California, encompasses more than forty-three square miles of mesas and canyons in northern New Mexico. A Department of Energy national laboratory, Los Alamos is one of the largest multidisciplinary, multiprogram laboratories in the world. Our mission, to apply science and engineering capabilities to problems of national security, has expanded to include a broad array of programs. We conduct extensive research in energy, nuclear safeguards and security, biomedical science, computational science, environmental protection and cleanup, materials science, and other basic sciences. The Energy Technology Programs Office is responsible for overseeing and developing programs in three strategic areas: energy systems and the environment, transportation and infrastructure, and integrated chemicals and materials processing. Our programs focus on developing reliable, economic and environmentally sound technologies that can help ensure an adequate supply of energy for the nation. To meet these needs, we are involved in programs that range from new and enhanced oil recovery technologies and tapping renewable energy sources, through efforts in industrial processes, electric power systems, clean coal technologies, civilian radioactive waste, high temperature superconductivity, to studying the environmental effects of energy use.

  14. Transport, radiative, and dynamical effects of the antarctic ozone hole: A GFDL 'SKYHI' model experiment

    SciTech Connect

    Mahlman, J.D.; Pinto, J.P.; Umscheid, L.J.

    1994-02-15

    The Geophysical Fluid Dynamics Laboratory 'SKYHI' general circulation model has been used to simulate the effect of the Antarctic 'ozone hole' phenomenon on the radiative and dynamical environment of the lower stratosphere. Both the polar ozone destruction and photochemical restoration chemistries are calculated by parameterized simplifications of the still uncertain, more complete chemical processes. The modeled total column ozone depletions are near 25% in spring over Antarctica, with 1% depletion reaching equatorial latitudes by the end of the 4 1/2 year model experiment. In the lower stratosphere, ozone reductions of 5% reach to the equator. Large coolings of about 8 C are simulated in the lower stratosphere over Antarctica in late spring, while a general cooling of about 1-1.5 C is present throughout the Southern Hemisphere lower stratosphere. The model atmosphere experiences a long-term positive temperature-chemical feedback because significant ozone reductions carry over into the next winter. The overall temperature response to the reduced ozone is essentially radiative in character. However, substantial dynamical changes are induced by the ozone hole effect. The Antarctic middle stratosphere in late spring warms by about 6 C over Antarctica and the lower mid-latitude stratosphere warms by approximately one degree. These warming spots are produced mainly by an increased residual circulation intensity.

  15. Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC

    NASA Technical Reports Server (NTRS)

    Li, Xinlin; Roth, I.; Temerin, M.; Wygant, J. R.; Hudson, M. K.; Blake, J. B.

    1993-01-01

    We model the rapid (about 1 min) formation of a new electron radiation belt at L about or = 2.5 that resulted from the Storm Sudden Commencement (SSC) of March 24, 1991 as observed by the Combined Release and Radiation Effects Satellite (CRRES) satellite. Guided by the observed electric and magnetic fields, we represent the time-dependent magnetospheric electric field during the SSC by an asymmetric bipolar pulse that is associated with the compression and relaxation of the Earth's magnetic field. We follow the electrons using a relativistic guiding center code. The test-particle simulations show that electrons with energies of a few MeV at L greater than 6 were energized up to 40 MeV and transported to L about or = 2.5 during a fraction of their drift period. The energization process conserves the first adiabatic invariant and is enhanced due to resonance of the electron drift motion with the time-varying electric field. Our simulation results, with an initial W(exp -8) energy flux spectra, reproduce the observed electron drift echoes and show that the interplanetary shock impacted the magnetosphere between 1500 and 1800 MLT.

  16. Real-Time Airborne Gamma-Ray Background Estimation Using NASVD with MLE and Radiation Transport for Calibration

    SciTech Connect

    Kulisek, Jonathan A.; Schweppe, John E.; Stave, Sean C.; Bernacki, Bruce E.; Jordan, David V.; Stewart, Trevor N.; Seifert, Carolyn E.; Kernan, Warnick J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements. This method is built upon on the noise-adjusted singular value decomposition (NASVD) technique that was previously developed for estimating the potassium (K), uranium (U), and thorium (T) concentrations in soil post-flight. The method can be calibrated using K, U, and T spectra determined from radiation transport simulations along with basis functions, which may be determined empirically by applying maximum likelihood estimation (MLE) to previously measured airborne gamma-ray spectra. The method was applied to both measured and simulated airborne gamma-ray spectra, with and without man-made radiological source injections. Compared to schemes based on simple averaging, this technique was less sensitive to background contamination from the injected man-made sources and may be particularly useful when the gamma-ray background frequently changes during the course of the flight.

  17. The FLUKA radiation transport code and its use for space problems.

    PubMed

    Ferrari, A; Ranft, J; Sala, P R

    2001-01-01

    FLUKA is a multiparticle transport code capable of handling hadronic and electromagnetic showers up to very high energies (100 TeV), widely used for radioprotection and detector simulation studies. The physical models embedded into FLUKA are briefly described and their capabilities demonstrated against available experimental data. The complete modelling of cosmic ray showers in the earth atmosphere with FLUKA is also described, and its relevance for benchmarking the code for space-like environments discussed. Finally, the ongoing developments of the physical models of the code are presented and discussed.

  18. Towards Robust Discontinuous Galerkin Methods for General Relativistic Neutrino Radiation Transport

    NASA Astrophysics Data System (ADS)

    Endeve, E.; Hauck, C. D.; Xing, Y.; Mezzacappa, A.

    2015-10-01

    With an eye towards simulating neutrino transport in core-collapse supernovae, we have developed a conservative, robust, and high-order numerical method for solving the general relativistic phase space advection problem in stationary spacetimes. The method achieves high-order accuracy using Discontinuous Galerkin discretization and Runge-Kutta time integration. For robustness, care is taken to ensure that the physical bounds on the phase space distribution function are preserved; i.e., f ∈ [0,1]. We briefly describe the bound-preserving scheme, and present results from numerical experiments in spherical symmetry adopting the Schwarzschild metric, which demonstrate that the method preserves the bounds on the distribution function.

  19. A robust SN-DG-approximation for radiation transport in optically thick and diffusive regimes

    NASA Astrophysics Data System (ADS)

    Ragusa, J. C.; Guermond, J.-L.; Kanschat, G.

    2012-02-01

    We introduce a new discontinuous Galerkin (DG) method with reduced upwind stabilization for the linear Boltzmann equation applied to particle transport. The asymptotic analysis demonstrates that the new formulation does not suffer from the limitations of standard upwind methods in the thick diffusive regime; in particular, the new method yields the correct diffusion limit for any approximation order, including piecewise constant discontinuous finite elements. Numerical tests on well-established benchmark problems demonstrate the superiority of the new method. The improvement is particularly significant when employing piecewise constant DG approximation for which standard upwinding is known to perform poorly in the thick diffusion limit.

  20. A robotic system to conduct radiation and contamination surveys on nuclear waste transport casks

    SciTech Connect

    Harrigan, R.W.; Sanders, T.L.

    1990-06-01

    The feasibility of performing, numerous spent fuel cask operations using fully integrated robotic systems is under evaluation. Using existing technology, operational and descriptive software and hardware in the form of robotic end effectors are being designed in conjunction with interfacing cask components. A robotic radiation and contamination survey system has been developed and used on mock-up cask hardware to evaluate the impact of such fully automated operations on cask design features and productivity. Based on experience gained from the survey system, numerous health physics operations can be reliably performed with little human intervention using a fully automated system. Such operations can also significantly reduce time requirements for cask-receiving operations. 7 refs., 51 figs., 6 tabs.