Science.gov

Sample records for accelerator physics code

  1. ACCELERATION PHYSICS CODE WEB REPOSITORY.

    SciTech Connect

    WEI, J.

    2006-06-26

    In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking.

  2. Accelerator Physics Code Web Repository

    SciTech Connect

    Zimmermann, F.; Basset, R.; Bellodi, G.; Benedetto, E.; Dorda, U.; Giovannozzi, M.; Papaphilippou, Y.; Pieloni, T.; Ruggiero, F.; Rumolo, G.; Schmidt, F.; Todesco, E.; Zotter, B.W.; Payet, J.; Bartolini, R.; Farvacque, L.; Sen, T.; Chin, Y.H.; Ohmi, K.; Oide, K.; Furman, M.; /LBL, Berkeley /Oak Ridge /Pohang Accelerator Lab. /SLAC /TRIUMF /Tech-X, Boulder /UC, San Diego /Darmstadt, GSI /Rutherford /Brookhaven

    2006-10-24

    In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking.

  3. Applications of the ARGUS code in accelerator physics

    NASA Astrophysics Data System (ADS)

    Petillo, J. J.; Mankofsky, A.; Krueger, W. A.; Kostas, C.; Mondelli, A. A.; Drobot, A. T.

    1993-12-01

    ARGUS is a three-dimensional, electromagnetic, particle-in-cell (PIC) simulation code that is being distributed to U.S. accelerator laboratories in collaboration between Science Applications International Corporation (SAICTM) and the Los Alamos Accelerator Code Group (LAACG). It uses a modular architecture that allows multiple physics modules to share common utilities for grid and structure input, memory management, disk I/O, and diagnostics. Physics modules are in place for electrostatic and electromagnetic field solutions, frequency-domain (eigenvalue) solutions, time-dependent PIC, and steady-state PIC simulations. All of the modules are implemented with a domain-decomposition architecture that allows large problems to be broken up into pieces that fit in core and that facilitates the adaptation of ARGUS for parallel processing. ARGUS operates on either Cray or workstation platforms, and a MOTIF-based user interface is available for X-windows terminals. Applications of ARGUS in accelerator physics and design are described in this paper.

  4. Physics models in the MARS15 code for accelerator and space applications.

    SciTech Connect

    Mokhov, N. V.; Gudima, K. K.; Mashnik, S. G.; Rakhno, I. L.; Sierk, A. J.; Striganov, S.

    2004-01-01

    The MARS code system, developed over 30 years, is a set of Monte Carlo programs for detailed simulation of hadronic and electromagnetic cascades in an arbitrary geometry of accelerator, detector and spacecraft components with particle energy ranging from a fraction of an electron volt up to 100 TeV. The new MARS15 (2004) version is described with an emphasis on modeling physics processes. This includes an extended list of elementary particles and arbitrary heavy ions, their interaction cross-sections, inclusive and exclusive nuclear event generators, photo - hadron production, correlated ionization energy loss and multiple Coulomb scattering, nuclide production and residual activation, and radiation damage (DPA). In particular, the details of a new model for leading baryon production and implementation of advanced versions of the Cascade-Exciton Model (CEM03), and the Los Alamos version of Quark-Gluon String Model (LAQGSM03) are given. The applications that are motivating these developments, needs for better nuclear data, and future physics improvements are described.

  5. GPU acceleration of the Locally Selfconsistent Multiple Scattering code for first principles calculation of the ground state and statistical physics of materials

    DOE PAGES

    Eisenbach, Markus; Larkin, Jeff; Lutjens, Justin; ...

    2016-07-12

    The Locally Self-consistent Multiple Scattering (LSMS) code solves the first principles Density Functional theory Kohn–Sham equation for a wide range of materials with a special focus on metals, alloys and metallic nano-structures. It has traditionally exhibited near perfect scalability on massively parallel high performance computer architectures. In this paper, we present our efforts to exploit GPUs to accelerate the LSMS code to enable first principles calculations of O(100,000) atoms and statistical physics sampling of finite temperature properties. We reimplement the scattering matrix calculation for GPUs with a block matrix inversion algorithm that only uses accelerator memory. Finally, using the Craymore » XK7 system Titan at the Oak Ridge Leadership Computing Facility we achieve a sustained performance of 14.5PFlop/s and a speedup of 8.6 compared to the CPU only code.« less

  6. GPU acceleration of the Locally Selfconsistent Multiple Scattering code for first principles calculation of the ground state and statistical physics of materials

    SciTech Connect

    Eisenbach, Markus; Larkin, Jeff; Lutjens, Justin; Rennich, Steven; Rogers, James H.

    2016-07-12

    The Locally Self-consistent Multiple Scattering (LSMS) code solves the first principles Density Functional theory Kohn–Sham equation for a wide range of materials with a special focus on metals, alloys and metallic nano-structures. It has traditionally exhibited near perfect scalability on massively parallel high performance computer architectures. In this paper, we present our efforts to exploit GPUs to accelerate the LSMS code to enable first principles calculations of O(100,000) atoms and statistical physics sampling of finite temperature properties. We reimplement the scattering matrix calculation for GPUs with a block matrix inversion algorithm that only uses accelerator memory. Finally, using the Cray XK7 system Titan at the Oak Ridge Leadership Computing Facility we achieve a sustained performance of 14.5PFlop/s and a speedup of 8.6 compared to the CPU only code.

  7. LEGO: A Modular Accelerator Design Code

    NASA Astrophysics Data System (ADS)

    Cai, Y.; Irwin, J.

    1997-05-01

    An object-oriented accelerator design code has been designed and implemented in a simple and modular fashion. It contains all major features of its predecessors TRACY and DESPOT. All physics of single-particle dynamics is implemented based on the Hamiltonian in the local frame of the component. Components can be moved arbitrarily in three dimensional space. Several symplectic integrators are used to approximate the integration of the local Hamiltonians. A differential algebra class is introduced to extract a Taylor map up to an arbitrary order. Analysis of optics is done in the same way for both the linear and non-linear cases. Currently the code is used to design and simulate the lattices of the PEP-II. It will be used for the commissioning of the machines as well.

  8. VLHC accelerator physics

    SciTech Connect

    Michael Blaskiewicz et al.

    2001-11-01

    A six-month design study for a future high energy hadron collider was initiated by the Fermilab director in October 2000. The request was to study a staged approach where a large circumference tunnel is built that initially would house a low field ({approx}2 T) collider with center-of-mass energy greater than 30 TeV and a peak (initial) luminosity of 10{sup 34} cm{sup -2}s{sup -1}. The tunnel was to be scoped, however, to support a future upgrade to a center-of-mass energy greater than 150 TeV with a peak luminosity of 2 x 10{sup 34} cm{sup -2} sec{sup -1} using high field ({approx} 10 T) superconducting magnet technology. In a collaboration with Brookhaven National Laboratory and Lawrence Berkeley National Laboratory, a report of the Design Study was produced by Fermilab in June 2001. 1 The Design Study focused on a Stage 1, 20 x 20 TeV collider using a 2-in-1 transmission line magnet and leads to a Stage 2, 87.5 x 87.5 TeV collider using 10 T Nb{sub 3}Sn magnet technology. The article that follows is a compilation of accelerator physics designs and computational results which contributed to the Design Study. Many of the parameters found in this report evolved during the study, and thus slight differences between this text and the Design Study report can be found. The present text, however, presents the major accelerator physics issues of the Very Large Hadron Collider as examined by the Design Study collaboration and provides a basis for discussion and further studies of VLHC accelerator parameters and design philosophies.

  9. French nuclear physics accelerator opens

    NASA Astrophysics Data System (ADS)

    Dumé, Belle

    2016-12-01

    A new €140m particle accelerator for nuclear physics located at the French Large Heavy Ion National Accelerator (GANIL) in Caen was inaugurated last month in a ceremony attended by French president François Hollande.

  10. Utilizing GPUs to Accelerate Turbomachinery CFD Codes

    NASA Technical Reports Server (NTRS)

    MacCalla, Weylin; Kulkarni, Sameer

    2016-01-01

    GPU computing has established itself as a way to accelerate parallel codes in the high performance computing world. This work focuses on speeding up APNASA, a legacy CFD code used at NASA Glenn Research Center, while also drawing conclusions about the nature of GPU computing and the requirements to make GPGPU worthwhile on legacy codes. Rewriting and restructuring of the source code was avoided to limit the introduction of new bugs. The code was profiled and investigated for parallelization potential, then OpenACC directives were used to indicate parallel parts of the code. The use of OpenACC directives was not able to reduce the runtime of APNASA on either the NVIDIA Tesla discrete graphics card, or the AMD accelerated processing unit. Additionally, it was found that in order to justify the use of GPGPU, the amount of parallel work being done within a kernel would have to greatly exceed the work being done by any one portion of the APNASA code. It was determined that in order for an application like APNASA to be accelerated on the GPU, it should not be modular in nature, and the parallel portions of the code must contain a large portion of the code's computation time.

  11. Code generation of RHIC accelerator device objects

    SciTech Connect

    Olsen, R.H.; Hoff, L.; Clifford, T.

    1995-12-01

    A RHIC Accelerator Device Object is an abstraction which provides a software view of a collection of collider control points known as parameters. A grammar has been defined which allows these parameters, along with code describing methods for acquiring and modifying them, to be specified efficiently in compact definition files. These definition files are processed to produce C++ source code. This source code is compiled to produce an object file which can be loaded into a front end computer. Each loaded object serves as an Accelerator Device Object class definition. The collider will be controlled by applications which set and get the parameters in instances of these classes using a suite of interface routines. Significant features of the grammar are described with details about the generated C++ code.

  12. Superdense Coding with Uniformly Accelerated Particle

    NASA Astrophysics Data System (ADS)

    Farahmand, Mehrnoosh; Mohammadzadeh, Hosein; Mehri-Dehnavi, Hossein; Rahimi, Robabeh

    2017-03-01

    We study superdense coding with uniformly accelerated particle in single mode approximation and beyond single mode approximation. We use four different functions, the capacity of superdense coding, negativity, discord and the probability of success for evaluating the final results. In single mode approximation, all the four functions behave as expected, however in beyond single mode approximation, except the probability of success, the other three functions represent peculiar behaviors at least for special ranges where the beyond single mode approximation is strong.

  13. SPEAR3 Accelerator Physics Update

    SciTech Connect

    Safranek, James A.; Corbett, W.Jeff; Gierman, S.; Hettel, R.O.; Huang, X.; Nosochkov, Yuri; Sebek, Jim; Terebilo, Andrei; /SLAC

    2007-11-02

    The SPEAR3 storage ring at Stanford Synchrotron Radiation Laboratory has been delivering photon beams for three years. We will give an overview of recent and ongoing accelerator physics activities, including 500 mA fills, work toward top-off injection, long-term orbit stability characterization and improvement, fast orbit feedback, new chicane optics, low alpha optics & short bunches, low emittance optics, and MATLAB software. The accelerator physics group has a strong program to characterize and improve SPEAR3 performance

  14. 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.}

  15. Accelerator physics and modeling: Proceedings

    SciTech Connect

    Parsa, Z.

    1991-12-31

    This report contains papers on the following topics: Physics of high brightness beams; radio frequency beam conditioner for fast-wave free-electron generators of coherent radiation; wake-field and space-charge effects on high brightness beams. Calculations and measured results for BNL-ATF; non-linear orbit theory and accelerator design; general problems of modeling for accelerators; development and application of dispersive soft ferrite models for time-domain simulation; and bunch lengthening in the SLC damping rings.

  16. Accelerator physics and modeling: Proceedings

    SciTech Connect

    Parsa, Z.

    1991-01-01

    This report contains papers on the following topics: Physics of high brightness beams; radio frequency beam conditioner for fast-wave free-electron generators of coherent radiation; wake-field and space-charge effects on high brightness beams. Calculations and measured results for BNL-ATF; non-linear orbit theory and accelerator design; general problems of modeling for accelerators; development and application of dispersive soft ferrite models for time-domain simulation; and bunch lengthening in the SLC damping rings.

  17. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

    SciTech Connect

    Siemann, R.H.; /SLAC

    2011-10-24

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  18. Accelerator science in medical physics.

    PubMed

    Peach, K; Wilson, P; Jones, B

    2011-12-01

    The use of cyclotrons and synchrotrons to accelerate charged particles in hospital settings for the purpose of cancer therapy is increasing. Consequently, there is a growing demand from medical physicists, radiographers, physicians and oncologists for articles that explain the basic physical concepts of these technologies. There are unique advantages and disadvantages to all methods of acceleration. Several promising alternative methods of accelerating particles also have to be considered since they will become increasingly available with time; however, there are still many technical problems with these that require solving. This article serves as an introduction to this complex area of physics, and will be of benefit to those engaged in cancer therapy, or who intend to acquire such technologies in the future.

  19. Accelerator science in medical physics

    PubMed Central

    Peach, K; Wilson, P; Jones, B

    2011-01-01

    The use of cyclotrons and synchrotrons to accelerate charged particles in hospital settings for the purpose of cancer therapy is increasing. Consequently, there is a growing demand from medical physicists, radiographers, physicians and oncologists for articles that explain the basic physical concepts of these technologies. There are unique advantages and disadvantages to all methods of acceleration. Several promising alternative methods of accelerating particles also have to be considered since they will become increasingly available with time; however, there are still many technical problems with these that require solving. This article serves as an introduction to this complex area of physics, and will be of benefit to those engaged in cancer therapy, or who intend to acquire such technologies in the future. PMID:22374548

  20. PAC++: Object-oriented platform for accelerator codes

    SciTech Connect

    Malitsky, N.; Reshetov, A.; Bourianoff, G.

    1994-06-01

    Software packages in accelerator physics have relatively long life cycles. They had been developed and used for a wide range of accelerators in the past as well as for the current projects. For example, the basic algorithms written in the first accelerator Program TRANSPORT are actual for design of most magnet systems. Most of these packages had been implemented on Fortran. But this language is rather inconvenient as a basic language for large integrated projects that possibly could include real-time data acquisition, data base access, graphic riser interface modules (GUI), arid other features. Some later accelerator programs had been based on object-oriented tools (primarily, C++ language). These range from systems for advanced theoretical studies to control system software. For the new generations of accelerators it would be desirable to have an integrated platform in which all simulation and control tasks will be considered with one point of view. In this report the basic principles of an object-oriented platform for accelerator research software (PAC++) are suggested and analyzed. Primary objectives of this work are to enable efficient self-explaining realization of the accelerator concepts and to provide an integrated environment for the updating and the developing of the code.

  1. Compensation Techniques in Accelerator Physics

    SciTech Connect

    Sayed, Hisham Kamal

    2011-05-01

    Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

  2. Analytical tools in accelerator physics

    SciTech Connect

    Litvinenko, V.N.

    2010-09-01

    This paper is a sub-set of my lectures presented in the Accelerator Physics course (USPAS, Santa Rosa, California, January 14-25, 2008). It is based on my notes I wrote during period from 1976 to 1979 in Novosibirsk. Only few copies (in Russian) were distributed to my colleagues in Novosibirsk Institute of Nuclear Physics. The goal of these notes is a complete description starting from the arbitrary reference orbit, explicit expressions for 4-potential and accelerator Hamiltonian and finishing with parameterization with action and angle variables. To a large degree follow logic developed in Theory of Cyclic Particle Accelerators by A.A.Kolmensky and A.N.Lebedev [Kolomensky], but going beyond the book in a number of directions. One of unusual feature is these notes use of matrix function and Sylvester formula for calculating matrices of arbitrary elements. Teaching the USPAS course motivated me to translate significant part of my notes into the English. I also included some introductory materials following Classical Theory of Fields by L.D. Landau and E.M. Liftsitz [Landau]. A large number of short notes covering various techniques are placed in the Appendices.

  3. GeoPhysical Analysis Code

    SciTech Connect

    2011-05-21

    GPAC is a code that integrates open source libraries for element formulations, linear algebra, and I/O with two main LLNL-Written components: (i) a set of standard finite elements physics solvers for rersolving Darcy fluid flow, explicit mechanics, implicit mechanics, and fluid-mediated fracturing, including resolution of contact both implicity and explicity, and (ii) a MPI-based parallelization implementation for use on generic HPC distributed memory architectures. The resultant code can be used alone for linearly elastic problems and problems involving hydraulic fracturing, where the mesh topology is dynamically changed. The key application domain is for low-rate stimulation and fracture control in subsurface reservoirs (e.g., enhanced geothermal sites and unconventional shale gas stimulation). GPAC also has interfaces to call external libraries for, e.g., material models and equations of state; however, LLNL-developed EOS and material models will not be part of the current release.

  4. GeoPhysical Analysis Code

    SciTech Connect

    2012-12-21

    GPAC is a code that integrates open source libraries for element formulations, linear algebra, and I/O with two main LLNL-written components: (i) a set of standard finite, discrete, and discontinuous displacement element physics solvers for resolving Darcy fluid flow, explicit mechanics, implicit mechanics, fault rupture and earthquake nucleation, and fluid-mediated fracturing, including resolution of physcial behaviors both implicity and explicity, and (ii) a MPI-based parallelization implementation for use on generic HPC distributed memory architectures. The resultant code can be used alone for linearly elastic problems; ploblems involving hydraulic fracturing, where the mesh topology is dynamically changed; fault rupture modeling and seismic risk assessment; and general granular materials behavior. The key application domain is for low-rate stimulation and fracture control in subsurface reservoirs (e.g., enhanced geothermal sites and unconventional shale gas stimulation). GPAC also has interfaces to call external libraries for , e.g., material models and equations of state; however, LLNL-developed EOS and material models will not be part of the current release. CPAC's secondary applications include modeling fault evolution for predicting the statistical distribution of earthquake events and to capture granular materials behavior under different load paths.

  5. Nonlinear Krylov acceleration of reacting flow codes

    SciTech Connect

    Kumar, S.; Rawat, R.; Smith, P.; Pernice, M.

    1996-12-31

    We are working on computational simulations of three-dimensional reactive flows in applications encompassing a broad range of chemical engineering problems. Examples of such processes are coal (pulverized and fluidized bed) and gas combustion, petroleum processing (cracking), and metallurgical operations such as smelting. These simulations involve an interplay of various physical and chemical factors such as fluid dynamics with turbulence, convective and radiative heat transfer, multiphase effects such as fluid-particle and particle-particle interactions, and chemical reaction. The governing equations resulting from modeling these processes are highly nonlinear and strongly coupled, thereby rendering their solution by traditional iterative methods (such as nonlinear line Gauss-Seidel methods) very difficult and sometimes impossible. Hence we are exploring the use of nonlinear Krylov techniques (such as CMRES and Bi-CGSTAB) to accelerate and stabilize the existing solver. This strategy allows us to take advantage of the problem-definition capabilities of the existing solver. The overall approach amounts to using the SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) method and its variants as nonlinear preconditioners for the nonlinear Krylov method. We have also adapted a backtracking approach for inexact Newton methods to damp the Newton step in the nonlinear Krylov method. This will be a report on work in progress. Preliminary results with nonlinear GMRES have been very encouraging: in many cases the number of line Gauss-Seidel sweeps has been reduced by about a factor of 5, and increased robustness of the underlying solver has also been observed.

  6. The Particle Accelerator Simulation Code PyORBIT

    SciTech Connect

    Gorlov, Timofey V; Holmes, Jeffrey A; Cousineau, Sarah M; Shishlo, Andrei P

    2015-01-01

    The particle accelerator simulation code PyORBIT is presented. The structure, implementation, history, parallel and simulation capabilities, and future development of the code are discussed. The PyORBIT code is a new implementation and extension of algorithms of the original ORBIT code that was developed for the Spallation Neutron Source accelerator at the Oak Ridge National Laboratory. The PyORBIT code has a two level structure. The upper level uses the Python programming language to control the flow of intensive calculations performed by the lower level code implemented in the C++ language. The parallel capabilities are based on MPI communications. The PyORBIT is an open source code accessible to the public through the Google Open Source Projects Hosting service.

  7. GAMER: GPU-accelerated Adaptive MEsh Refinement code

    NASA Astrophysics Data System (ADS)

    Schive, Hsi-Yu; Tsai, Yu-Chih; Chiueh, Tzihong

    2016-12-01

    GAMER (GPU-accelerated Adaptive MEsh Refinement) serves as a general-purpose adaptive mesh refinement + GPU framework and solves hydrodynamics with self-gravity. The code supports adaptive mesh refinement (AMR), hydrodynamics with self-gravity, and a variety of GPU-accelerated hydrodynamic and Poisson solvers. It also supports hybrid OpenMP/MPI/GPU parallelization, concurrent CPU/GPU execution for performance optimization, and Hilbert space-filling curve for load balance. Although the code is designed for simulating galaxy formation, it can be easily modified to solve a variety of applications with different governing equations. All optimization strategies implemented in the code can be inherited straightforwardly.

  8. Relationship of FEL physics to accelerator physics

    SciTech Connect

    Morton, P.L.

    1981-08-01

    The beam dynamics and operation of a free electron laser are discussed after a description of accelerator beam dynamics. Various wiggler field schemes are studied including the constant parameter wiggler, the variable parameter wiggler, and the gain-expanded wiggler. (WHK)

  9. Theoretical problems in accelerator physics. Progress report

    SciTech Connect

    Kroll, N.M.

    1993-08-01

    This report discusses the following topics in accelerator physics: radio frequency pulse compression and power transport; computational methods for the computer analysis of microwave components; persistent wakefields associated with waveguide damping of higher order modes; and photonic band gap cavities.

  10. Physics and Accelerator Applications of RF Superconductivity

    SciTech Connect

    H. Padamsee; K. W. Shepard; Ron Sundelin

    1993-12-01

    A key component of any particle accelerator is the device that imparts energy gain to the charged particle. This is usually an electromagnetic cavity resonating at a microwave frequency, chosen between 100 and 3000 MHz. Serious attempts to utilize superconductors for accelerating cavities were initiated more than 25 years ago with the acceleration of electrons in a lead-plated resonator at Stanford University (1). The first full-scale accelerator, the Stanford SCA, was completed in 1978 at the High Energy Physics Laboratory (HEPL) (2). Over the intervening one and a half decades, superconducting cavities have become increasingly important to particle accelerators for nuclear physics and high energy physics. For continuous operation, as is required for many applications, the power dissipation in the walls of a copper structure is quite substantial, for example, 0.1 megawatts per meter of structure operating at an accelerating field of 1 million volts/meter (MV/m). since losses increase as the square of the accelerating field, copper cavities become severely uneconomical as demand for higher fields grows with the higher energies called for by experimenters to probe ever deeper into the structure of matter. Rf superconductivity has become an important technology for particle accelerators. Practical structures with attractive performance levels have been developed for a variety of applications, installed in the targeted accelerators, and operated over significant lengths of time. Substantial progress has been made in understanding field and Q limitations and in inventing cures to advance performance. The technical and economical potential of rf superconductivity makes it an important candidate for future advanced accelerators for free electron lasers, for nuclear physics, and for high energy physics, at the luminosity as well as at the energy frontiers.

  11. New accelerators in high-energy physics

    SciTech Connect

    Blewett, J.P.

    1982-01-01

    First, I should like to mention a few new ideas that have appeared during the last few years in the accelerator field. A couple are of importance in the design of injectors, usually linear accelerators, for high-energy machines. Then I shall review some of the somewhat sensational accelerator projects, now in operation, under construction or just being proposed. Finally, I propose to mention a few applications of high-energy accelerators in fields other than high-energy physics. I realize that this is a digression from my title but I hope that you will find it interesting.

  12. Convergence acceleration of the Proteus computer code with multigrid methods

    NASA Technical Reports Server (NTRS)

    Demuren, A. O.; Ibraheem, S. O.

    1992-01-01

    Presented here is the first part of a study to implement convergence acceleration techniques based on the multigrid concept in the Proteus computer code. A review is given of previous studies on the implementation of multigrid methods in computer codes for compressible flow analysis. Also presented is a detailed stability analysis of upwind and central-difference based numerical schemes for solving the Euler and Navier-Stokes equations. Results are given of a convergence study of the Proteus code on computational grids of different sizes. The results presented here form the foundation for the implementation of multigrid methods in the Proteus code.

  13. Accelerator prospects for photon-photon physics

    SciTech Connect

    Hutton, A.

    1992-05-01

    This paper provides an overview of the accelerators in the world where two-photon physics could be carried out in the future. The list includes facilities where two-photon physics is already an integral part of the scientific program but also mentions some other machines where initiating new programs may be possible.

  14. Advances in Parallel Electromagnetic Codes for Accelerator Science and Development

    SciTech Connect

    Ko, Kwok; Candel, Arno; Ge, Lixin; Kabel, Andreas; Lee, Rich; Li, Zenghai; Ng, Cho; Rawat, Vineet; Schussman, Greg; Xiao, Liling; /SLAC

    2011-02-07

    Over a decade of concerted effort in code development for accelerator applications has resulted in a new set of electromagnetic codes which are based on higher-order finite elements for superior geometry fidelity and better solution accuracy. SLAC's ACE3P code suite is designed to harness the power of massively parallel computers to tackle large complex problems with the increased memory and solve them at greater speed. The US DOE supports the computational science R&D under the SciDAC project to improve the scalability of ACE3P, and provides the high performance computing resources needed for the applications. This paper summarizes the advances in the ACE3P set of codes, explains the capabilities of the modules, and presents results from selected applications covering a range of problems in accelerator science and development important to the Office of Science.

  15. Accelerator-based validation of shielding codes

    SciTech Connect

    Zeitlin, Cary; Heilbronn, Lawrence; Miller, Jack; Wilson, John W.

    2002-08-12

    The space radiation environment poses risks to astronaut health from a diverse set of sources, ranging from low-energy protons and electrons to highly-charged, high-energy atomic nuclei and their associated fragmentation products, including neutrons. The low-energy protons and electrons are the source of most of the radiation dose to Shuttle and ISS crews, while the more energetic particles that comprise the Galactic Cosmic Radiation (protons, He, and heavier nuclei up to Fe) will be the dominant source for crews on long-duration missions outside the earth's magnetic field. Because of this diversity of sources, a broad ground-based experimental effort is required to validate the transport and shielding calculations used to predict doses and dose-equivalents under various mission scenarios. The experimental program of the LBNL group, described here, focuses principally on measurements of charged particle and neutron production in high-energy heavy-ion fragmentation. Other aspects of the program include measurements of the shielding provided by candidate spacesuit materials against low-energy protons (particularly relevant to extra-vehicular activities in low-earth orbit), and the depth-dose relations in tissue for higher-energy protons. The heavy-ion experiments are performed at the Brookhaven National Laboratory's Alternating Gradient Synchrotron and the Heavy-Ion Medical Accelerator in Chiba in Japan. Proton experiments are performed at the Lawrence Berkeley National Laboratory's 88'' Cyclotron with a 55 MeV beam, and at the Loma Linda University Proton Facility with 100 to 250 MeV beam energies. The experimental results are an important component of the overall shielding program, as they allow for simple, well-controlled tests of the models developed to handle the more complex radiation environment in space.

  16. The plasma physics of shock acceleration

    NASA Technical Reports Server (NTRS)

    Jones, Frank C.; Ellison, Donald C.

    1991-01-01

    The history and theory of shock acceleration is reviewed, paying particular attention to theories of parallel shocks which include the backreaction of accelerated particles on the shock structure. The work that computer simulations, both plasma and Monte Carlo, are playing in revealing how thermal ions interact with shocks and how particle acceleration appears to be an inevitable and necessary part of the basic plasma physics that governs collisionless shocks is discussed. Some of the outstanding problems that still confront theorists and observers in this field are described.

  17. Modeling of Ionization Physics with the PIC Code OSIRIS

    SciTech Connect

    Deng, S.; Tsung, F.; Lee, S.; Lu, W.; Mori, W.B.; Katsouleas, T.; Muggli, P.; Blue, B.E.; Clayton, C.E.; O'Connell, C.; Dodd, E.; Decker, F.J.; Huang, C.; Hogan, M.J.; Hemker, R.; Iverson, R.H.; Joshi, C.; Ren, C.; Raimondi, P.; Wang, S.; Walz, D.; /Southern California U. /UCLA /SLAC

    2005-09-27

    When considering intense particle or laser beams propagating in dense plasma or gas, ionization plays an important role. Impact ionization and tunnel ionization may create new plasma electrons, altering the physics of wakefield accelerators, causing blue shifts in laser spectra, creating and modifying instabilities, etc. Here we describe the addition of an impact ionization package into the 3-D, object-oriented, fully parallel PIC code OSIRIS. We apply the simulation tool to simulate the parameters of the upcoming E164 Plasma Wakefield Accelerator experiment at the Stanford Linear Accelerator Center (SLAC). We find that impact ionization is dominated by the plasma electrons moving in the wake rather than the 30 GeV drive beam electrons. Impact ionization leads to a significant number of trapped electrons accelerated from rest in the wake.

  18. Recent developments and physics of the JQMD code

    NASA Astrophysics Data System (ADS)

    Niita, K.; Sato, T.; Iwase, H.; Sihver, L.; Mancusi, D.; Matsuda, N.; Iwamoto, Y.; Nakashima, H.; Sakamoto, Y.

    Accurate knowledge of the physics of nucleus-nucleus collisions is required in many application fields of accelerator facilities radiotherapy and space radiation Many kinds of model have been proposed so far to describe the physics of nucleus-nucleus collisions However most of them are restricted to the specific energy regime or specific phenomena Within various models the QMD Quantum Molecular Dynamics model is one of candidate for a microscopic model to describe various aspects of nuclear-nuclear collisions in a unified way In this decade we have been therefore developing the JQMD JAERI QMD code and included it into the transport code system PHITS Particle and Heavy Ion Transport code System as a calculation engine of nucleus-nucleus collisions The JQMD code has been tested in various aspects compared with the experimental data starting from the simplest cases such as N xN reactions up to the fragmentation processes of the nucleus-nucleus collisions In this paper we first describe the physics included in the JQMD code the effective interactions and the cross sections between the elementary particles Second we show many comparisons with the experimental data discussing the essential ingredients to reproduce the experimental data Particularly we stress an importance of the benchmark test for the simple cases such as N xN reactions Finally we describe the recent developments of the JQMD code

  19. TOPICS IN THE PHYSICS OF PARTICLE ACCELERATORS

    SciTech Connect

    Sessler, A.M.

    1984-07-01

    High energy physics, perhaps more than any other branch of science, is driven by technology. It is not the development of theory, or consideration of what measurements to make, which are the driving elements in our science. Rather it is the development of new technology which is the pacing item. Thus it is the development of new techniques, new computers, and new materials which allows one to develop new detectors and new particle-handling devices. It is the latter, the accelerators, which are at the heart of the science. Without particle accelerators there would be, essentially, no high energy physics. In fact. the advances in high energy physics can be directly tied to the advances in particle accelerators. Looking terribly briefly, and restricting one's self to recent history, the Bevatron made possible the discovery of the anti-proton and many of the resonances, on the AGS was found the {mu}-neutrino, the J-particle and time reversal non-invariance, on Spear was found the {psi}-particle, and, within the last year the Z{sub 0} and W{sup {+-}} were seen on the CERN SPS p-{bar p} collider. Of course one could, and should, go on in much more detail with this survey, but I think there is no need. It is clear that as better acceleration techniques were developed more and more powerful machines were built which, as a result, allowed high energy physics to advance. What are these techniques? They are very sophisticated and ever-developing. The science is very extensive and many individuals devote their whole lives to accelerator physics. As high energy experimental physicists your professional lives will be dominated by the performance of 'the machine'; i.e. the accelerator. Primarily you will be frustrated by the fact that it doesn't perform better. Why not? In these lectures, six in all, you should receive some appreciation of accelerator physics. We cannot, nor do we attempt, to make you into accelerator physicists, but we do hope to give you some insight into the

  20. Chemical vs. Physical Acceleration of Cement Hydration

    PubMed Central

    Bentz, Dale P.; Zunino, Franco; Lootens, Didier

    2016-01-01

    Cold weather concreting often requires the use of chemical accelerators to speed up the hydration reactions of the cement, so that setting and early-age strength development will occur in a timely manner. While calcium chloride (dihydrate – CaCl2·2H2O) is the most commonly used chemical accelerator, recent research using fine limestone powders has indicated their high proficiency for physically accelerating early-age hydration and reducing setting times. This paper presents a comparative study of the efficiency of these two approaches in accelerating hydration (as assessed via isothermal calorimetry), reducing setting times (Vicat needle), and increasing early-age mortar cube strength (1 d and 7 d). Both the CaCl2 and the fine limestone powder are used to replace a portion of the finest sand in the mortar mixtures, while keeping both the water-to-cement ratio and volume fractions of water and cement constant. Studies are conducted at 73.4 °F (23°C) and 50 °F (10 °C), so that activation energies can be estimated for the hydration and setting processes. Because the mechanisms of acceleration of the CaCl2 and limestone powder are different, a hybrid mixture with 1 % CaCl2 and 20 % limestone powder (by mass of cement) is also investigated. Both technologies are found to be viable options for reducing setting times and increasing early-age strengths, and it is hoped that concrete producers and contractors will consider the addition of fine limestone powder to their toolbox of techniques for assuring performance in cold weather and other concreting conditions where acceleration may be needed. PMID:28077884

  1. Convergence acceleration of the Proteus computer code with multigrid methods

    NASA Technical Reports Server (NTRS)

    Demuren, A. O.; Ibraheem, S. O.

    1995-01-01

    This report presents the results of a study to implement convergence acceleration techniques based on the multigrid concept in the two-dimensional and three-dimensional versions of the Proteus computer code. The first section presents a review of the relevant literature on the implementation of the multigrid methods in computer codes for compressible flow analysis. The next two sections present detailed stability analysis of numerical schemes for solving the Euler and Navier-Stokes equations, based on conventional von Neumann analysis and the bi-grid analysis, respectively. The next section presents details of the computational method used in the Proteus computer code. Finally, the multigrid implementation and applications to several two-dimensional and three-dimensional test problems are presented. The results of the present study show that the multigrid method always leads to a reduction in the number of iterations (or time steps) required for convergence. However, there is an overhead associated with the use of multigrid acceleration. The overhead is higher in 2-D problems than in 3-D problems, thus overall multigrid savings in CPU time are in general better in the latter. Savings of about 40-50 percent are typical in 3-D problems, but they are about 20-30 percent in large 2-D problems. The present multigrid method is applicable to steady-state problems and is therefore ineffective in problems with inherently unstable solutions.

  2. Comparisons of time explicit hybrid kinetic-fluid code Architect for Plasma Wakefield Acceleration with a full PIC code

    NASA Astrophysics Data System (ADS)

    Massimo, F.; Atzeni, S.; Marocchino, A.

    2016-12-01

    Architect, a time explicit hybrid code designed to perform quick simulations for electron driven plasma wakefield acceleration, is described. In order to obtain beam quality acceptable for applications, control of the beam-plasma-dynamics is necessary. Particle in Cell (PIC) codes represent the state-of-the-art technique to investigate the underlying physics and possible experimental scenarios; however PIC codes demand the necessity of heavy computational resources. Architect code substantially reduces the need for computational resources by using a hybrid approach: relativistic electron bunches are treated kinetically as in a PIC code and the background plasma as a fluid. Cylindrical symmetry is assumed for the solution of the electromagnetic fields and fluid equations. In this paper both the underlying algorithms as well as a comparison with a fully three dimensional particle in cell code are reported. The comparison highlights the good agreement between the two models up to the weakly non-linear regimes. In highly non-linear regimes the two models only disagree in a localized region, where the plasma electrons expelled by the bunch close up at the end of the first plasma oscillation.

  3. HotSpot Health Physics Codes

    SciTech Connect

    Homann, S. G.

    2013-04-18

    The HotSpot Health Physics Codes were created to provide emergency response personnel and emergency planners with a fast, field-portable set of software tools for evaluating insidents involving redioactive material. The software is also used for safety-analysis of facilities handling nuclear material. HotSpot provides a fast and usually conservative means for estimation the radiation effects associated with the short-term (less than 24 hours) atmospheric release of radioactive materials.

  4. HOTSPOT Health Physics codes for the PC

    SciTech Connect

    Homann, S.G.

    1994-03-01

    The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculation tool for evaluating accidents involving radioactive materials. HOTSPOT codes are a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT codes produce a consistent output for the same input assumptions and minimize the probability of errors associated with reading a graph incorrectly or scaling a universal nomogram during an emergency. The HOTSPOT codes are designed for short-term (less than 24 hours) release durations. Users requiring radiological release consequences for release scenarios over a longer time period, e.g., annual windrose data, are directed to such long-term models as CAPP88-PC (Parks, 1992). Users requiring more sophisticated modeling capabilities, e.g., complex terrain; multi-location real-time wind field data; etc., are directed to such capabilities as the Department of Energy`s ARAC computer codes (Sullivan, 1993). Four general programs -- Plume, Explosion, Fire, and Resuspension -- calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Other programs deal with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons. Additional programs estimate the dose commitment from the inhalation of any one of the radionuclides listed in the database of radionuclides; calibrate a radiation survey instrument for ground-survey measurements; and screen plutonium uptake in the lung (see FIDLER Calibration and LUNG Screening sections).

  5. Reliability enhancement of Navier-Stokes codes through convergence acceleration

    NASA Technical Reports Server (NTRS)

    Merkle, Charles L.; Dulikravich, George S.

    1995-01-01

    Methods for enhancing the reliability of Navier-Stokes computer codes through improving convergence characteristics are presented. The improving of these characteristics decreases the likelihood of code unreliability and user interventions in a design environment. The problem referred to as a 'stiffness' in the governing equations for propulsion-related flowfields is investigated, particularly in regard to common sources of equation stiffness that lead to convergence degradation of CFD algorithms. Von Neumann stability theory is employed as a tool to study the convergence difficulties involved. Based on the stability results, improved algorithms are devised to ensure efficient convergence in different situations. A number of test cases are considered to confirm a correlation between stability theory and numerical convergence. The examples of turbulent and reacting flow are presented, and a generalized form of the preconditioning matrix is derived to handle these problems, i.e., the problems involving additional differential equations for describing the transport of turbulent kinetic energy, dissipation rate and chemical species. Algorithms for unsteady computations are considered. The extension of the preconditioning techniques and algorithms derived for Navier-Stokes computations to three-dimensional flow problems is discussed. New methods to accelerate the convergence of iterative schemes for the numerical integration of systems of partial differential equtions are developed, with a special emphasis on the acceleration of convergence on highly clustered grids.

  6. MAPA: an interactive accelerator design code with GUI

    NASA Astrophysics Data System (ADS)

    Bruhwiler, David L.; Cary, John R.; Shasharina, Svetlana G.

    1999-06-01

    The MAPA code is an interactive accelerator modeling and design tool with an X/Motif GUI. MAPA has been developed in C++ and makes full use of object-oriented features. We present an overview of its features and describe how users can independently extend the capabilities of the entire application, including the GUI. For example, a user can define a new model for a focusing or accelerating element. If the appropriate form is followed, and the new element is "registered" with a single line in the specified file, then the GUI will fully support this user-defined element type after it has been compiled and then linked to the existing application. In particular, the GUI will bring up windows for modifying any relevant parameters of the new element type. At present, one can use the GUI for phase space tracking, finding fixed points and generating line plots for the Twiss parameters, the dispersion and the accelerator geometry. The user can define new types of simulations which the GUI will automatically support by providing a menu option to execute the simulation and subsequently rendering line plots of the resulting data.

  7. An integrated radiation physics computer code system.

    NASA Technical Reports Server (NTRS)

    Steyn, J. J.; Harris, D. W.

    1972-01-01

    An integrated computer code system for the semi-automatic and rapid analysis of experimental and analytic problems in gamma photon and fast neutron radiation physics is presented. Such problems as the design of optimum radiation shields and radioisotope power source configurations may be studied. The system codes allow for the unfolding of complex neutron and gamma photon experimental spectra. Monte Carlo and analytic techniques are used for the theoretical prediction of radiation transport. The system includes a multichannel pulse-height analyzer scintillation and semiconductor spectrometer coupled to an on-line digital computer with appropriate peripheral equipment. The system is geometry generalized as well as self-contained with respect to material nuclear cross sections and the determination of the spectrometer response functions. Input data may be either analytic or experimental.

  8. Particle-in-cell/accelerator code for space-charge dominated beam simulation

    SciTech Connect

    2012-05-08

    Warp is a multidimensional discrete-particle beam simulation program designed to be applicable where the beam space-charge is non-negligible or dominant. It is being developed in a collaboration among LLNL, LBNL and the University of Maryland. It was originally designed and optimized for heave ion fusion accelerator physics studies, but has received use in a broader range of applications, including for example laser wakefield accelerators, e-cloud studies in high enery accelerators, particle traps and other areas. At present it incorporates 3-D, axisymmetric (r,z) planar (x-z) and transverse slice (x,y) descriptions, with both electrostatic and electro-magnetic fields, and a beam envelope model. The code is guilt atop the Python interpreter language.

  9. The Mystery Behind the Code: Differentiated Instruction with Quick Response Codes in Secondary Physical Education

    ERIC Educational Resources Information Center

    Adkins, Megan; Wajciechowski, Misti R.; Scantling, Ed

    2013-01-01

    Quick response codes, better known as QR codes, are small barcodes scanned to receive information about a specific topic. This article explains QR code technology and the utility of QR codes in the delivery of physical education instruction. Consideration is given to how QR codes can be used to accommodate learners of varying ability levels as…

  10. Pulsed power accelerator for material physics experiments

    NASA Astrophysics Data System (ADS)

    Reisman, D. B.; Stoltzfus, B. S.; Stygar, W. A.; Austin, K. N.; Waisman, E. M.; Hickman, R. J.; Davis, J.-P.; Haill, T. A.; Knudson, M. D.; Seagle, C. T.; Brown, J. L.; Goerz, D. A.; Spielman, R. B.; Goldlust, J. A.; Cravey, W. R.

    2015-09-01

    We have developed the design of Thor: a pulsed power accelerator that delivers a precisely shaped current pulse with a peak value as high as 7 MA to a strip-line load. The peak magnetic pressure achieved within a 1-cm-wide load is as high as 100 GPa. Thor is powered by as many as 288 decoupled and transit-time isolated bricks. Each brick consists of a single switch and two capacitors connected electrically in series. The bricks can be individually triggered to achieve a high degree of current pulse tailoring. Because the accelerator is impedance matched throughout, capacitor energy is delivered to the strip-line load with an efficiency as high as 50%. We used an iterative finite element method (FEM), circuit, and magnetohydrodynamic simulations to develop an optimized accelerator design. When powered by 96 bricks, Thor delivers as much as 4.1 MA to a load, and achieves peak magnetic pressures as high as 65 GPa. When powered by 288 bricks, Thor delivers as much as 6.9 MA to a load, and achieves magnetic pressures as high as 170 GPa. We have developed an algebraic calculational procedure that uses the single brick basis function to determine the brick-triggering sequence necessary to generate a highly tailored current pulse time history for shockless loading of samples. Thor will drive a wide variety of magnetically driven shockless ramp compression, shockless flyer plate, shock-ramp, equation of state, material strength, phase transition, and other advanced material physics experiments.

  11. 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).

  12. SimTrack: A compact c++ code for particle orbit and spin tracking in accelerators

    SciTech Connect

    Luo, Yun

    2015-08-29

    SimTrack is a compact c++ code of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam–beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam–beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam–beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.

  13. SimTrack: A compact c++ code for particle orbit and spin tracking in accelerators

    DOE PAGES

    Luo, Yun

    2015-08-29

    SimTrack is a compact c++ code of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam–beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam–beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam–beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture,more » physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.« less

  14. Guide to accelerator physics program SYNCH: VAX version 1987. 2

    SciTech Connect

    Parsa, Z.; Courant, E.

    1987-01-01

    This guide is written to accommodate users of Accelerator Physics Data Base BNLDAG::DUAO:(PARSA1). It describes the contents of the on line Accelerator Physics data base DUAO:(PARSA1.SYNCH). SYNCH is a computer program used for the design and analysis of synchrotrons, storage rings and beamlines.

  15. Advanced Computing Tools and Models for Accelerator Physics

    SciTech Connect

    Ryne, Robert; Ryne, Robert D.

    2008-06-11

    This paper is based on a transcript of my EPAC'08 presentation on advanced computing tools for accelerator physics. Following an introduction I present several examples, provide a history of the development of beam dynamics capabilities, and conclude with thoughts on the future of large scale computing in accelerator physics.

  16. Physical activities to enhance an understanding of acceleration

    NASA Astrophysics Data System (ADS)

    Lee, S. A.

    2006-03-01

    On the basis of their everyday experiences, students have developed an understanding of many of the concepts of mechanics by the time they take their first physics course. However, an accurate understanding of acceleration remains elusive. Many students have difficulties distinguishing between velocity and acceleration. In this report, a set of physical activities to highlight the differences between acceleration and velocity are described. These activities involve running and walking on sand (such as an outdoor volleyball court).

  17. The Influence of Accelerator Science on Physics Research

    NASA Astrophysics Data System (ADS)

    Haussecker, Enzo F.; Chao, Alexander W.

    2011-06-01

    We evaluate accelerator science in the context of its contributions to the physics community. We address the problem of quantifying these contributions and present a scheme for a numerical evaluation of them. We show by using a statistical sample of important developments in modern physics that accelerator science has influenced 28% of post-1938 physicists and also 28% of post-1938 physics research. We also examine how the influence of accelerator science has evolved over time, and show that on average it has contributed to a physics Nobel Prize-winning research every 2.9 years.

  18. Fifty years of accelerator based physics at Chalk River

    SciTech Connect

    McKay, John W.

    1999-04-26

    The Chalk River Laboratories of Atomic Energy of Canada Ltd. was a major centre for Accelerator based physics for the last fifty years. As early as 1946, nuclear structure studies were started on Cockroft-Walton accelerators. A series of accelerators followed, including the world's first Tandem, and the MP Tandem, Superconducting Cyclotron (TASCC) facility that was opened in 1986. The nuclear physics program was shut down in 1996. This paper will describe some of the highlights of the accelerators and the research of the laboratory.

  19. Optimizing Nuclear Physics Codes on the XT5

    SciTech Connect

    Hartman-Baker, Rebecca J; Nam, Hai Ah

    2011-01-01

    Scientists studying the structure and behavior of the atomic nucleus require immense high-performance computing resources to gain scientific insights. Several nuclear physics codes are capable of scaling to more than 100,000 cores on Oak Ridge National Laboratory's petaflop Cray XT5 system, Jaguar. In this paper, we present our work on optimizing codes in the nuclear physics domain.

  20. Efficient modeling of plasma wakefield acceleration in quasi-non-linear-regimes with the hybrid code Architect

    NASA Astrophysics Data System (ADS)

    Marocchino, A.; Massimo, F.; Rossi, A. R.; Chiadroni, E.; Ferrario, M.

    2016-09-01

    In this paper we present a hybrid approach aiming to assess feasible plasma wakefield acceleration working points with reduced computation resources. The growing interest for plasma wakefield acceleration and especially the need to control with increasing precision the quality of the accelerated bunch demands for more accurate and faster simulations. Particle in cell codes are the state of the art technique to simulate the underlying physics, however the run-time represents the major drawback. Architect is a hybrid code that treats the bunch kinetically and the background electron plasma as a fluid, initialising bunches in vacuum so to take into account for the transition from vacuum to plasma. Architect solves directly the Maxwell's equations on a Yee lattice. Such an approach allows us to drastically reduce run time without loss of generality or accuracy up to the weakly non linear regime.

  1. The Future of Accelerator Physics. The Tamura Symposium Proceedings

    SciTech Connect

    Tajima, T.

    1996-04-01

    These proceedings represent the papers presented at the Tamura symposium on accelerator physics. The topics discussed include many novel ideas for future exploration, for example, 30TeV X 30TeV collider, Moebius accelerator, new magnets, new table{minus}top terawatt (T3) lasers, free space accelerators, advanced cooling of beams, including optical cooling,etc.. There were 30 papers presented at the symposium and 28 have been abstracted for the Energy Science and Technology database.(AIP)

  2. Summary report of working group 2: Computations for accelerator physics

    NASA Astrophysics Data System (ADS)

    Cowan, Benjamin M.; Benedetti, C.

    2017-03-01

    The Computations for Accelerator Physics Working Group reviewed recent progress in and surveyed the state of the art of computational modeling of advanced accelerators. This included applications to laser-plasma and structure-based accelerators as well as beam dynamics in circular colliders. Fundamental aspects of numerical modeling and direct particle interaction techniques were discussed. The Working Group also covered the implications of advanced compute architectures.

  3. Fluid Physics in a Fluctuating Acceleration Environment

    NASA Technical Reports Server (NTRS)

    Thomson, J. Ross; Drolet, Francois; Vinals, Jorge

    1996-01-01

    We summarize several aspects of an ongoing investigation of the effects that stochastic residual accelerations (g-jitter) onboard spacecraft can have on experiments conducted in a microgravity environment. The residual acceleration field is modeled as a narrow band noise, characterized by three independent parameters: intensity (g(exp 2)), dominant angular frequency Omega, and characteristic correlation time tau. Realistic values for these parameters are obtained from an analysis of acceleration data corresponding to the SL-J mission, as recorded by the SAMS instruments. We then use the model to address the random motion of a solid particle suspended in an incompressible fluid subjected to such random accelerations. As an extension, the effect of jitter on coarsening of a solid-liquid mixture is briefly discussed, and corrections to diffusion controlled coarsening evaluated. We conclude that jitter will not be significant in the experiment 'Coarsening of solid-liquid mixtures' to be conducted in microgravity. Finally, modifications to the location of onset of instability in systems driven by a random force are discussed by extending the standard reduction to the center manifold to the stochastic case. Results pertaining to time-modulated oscillatory convection are briefly discussed.

  4. Fluid Physics Under a Stochastic Acceleration Field

    NASA Technical Reports Server (NTRS)

    Vinals, Jorge

    2001-01-01

    The research summarized in this report has involved a combined theoretical and computational study of fluid flow that results from the random acceleration environment present onboard space orbiters, also known as g-jitter. We have focused on a statistical description of the observed g-jitter, on the flows that such an acceleration field can induce in a number of experimental configurations of interest, and on extending previously developed methodology to boundary layer flows. Narrow band noise has been shown to describe many of the features of acceleration data collected during space missions. The scale of baroclinically induced flows when the driving acceleration is random is not given by the Rayleigh number. Spatially uniform g-jitter induces additional hydrodynamic forces among suspended particles in incompressible fluids. Stochastic modulation of the control parameter shifts the location of the onset of an oscillatory instability. Random vibration of solid boundaries leads to separation of boundary layers. Steady streaming ahead of a modulated solid-melt interface enhances solute transport, and modifies the stability boundaries of a planar front.

  5. Accelerating Innovation: How Nuclear Physics Benefits Us All

    DOE R&D Accomplishments Database

    2011-01-01

    Innovation has been accelerated by nuclear physics in the areas of improving our health; making the world safer; electricity, environment, archaeology; better computers; contributions to industry; and training the next generation of innovators.

  6. SYMMETRY, HAMILTONIAN PROBLEMS AND WAVELETS IN ACCELERATOR PHYSICS

    SciTech Connect

    FEDOROVA,A.; ZEITLIN,M.; PARSA,Z.

    2000-03-31

    In this paper the authors consider applications of methods from wavelet analysis to nonlinear dynamical problems related to accelerator physics. In this approach they take into account underlying algebraical, geometrical and topological structures of corresponding problems.

  7. Convergence Acceleration and Documentation of CFD Codes for Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    Marquart, Jed E.

    2005-01-01

    The development and analysis of turbomachinery components for industrial and aerospace applications has been greatly enhanced in recent years through the advent of computational fluid dynamics (CFD) codes and techniques. Although the use of this technology has greatly reduced the time required to perform analysis and design, there still remains much room for improvement in the process. In particular, there is a steep learning curve associated with most turbomachinery CFD codes, and the computation times need to be reduced in order to facilitate their integration into standard work processes. Two turbomachinery codes have recently been developed by Dr. Daniel Dorney (MSFC) and Dr. Douglas Sondak (Boston University). These codes are entitled Aardvark (for 2-D and quasi 3-D simulations) and Phantom (for 3-D simulations). The codes utilize the General Equation Set (GES), structured grid methodology, and overset O- and H-grids. The codes have been used with success by Drs. Dorney and Sondak, as well as others within the turbomachinery community, to analyze engine components and other geometries. One of the primary objectives of this study was to establish a set of parametric input values which will enhance convergence rates for steady state simulations, as well as reduce the runtime required for unsteady cases. The goal is to reduce the turnaround time for CFD simulations, thus permitting more design parametrics to be run within a given time period. In addition, other code enhancements to reduce runtimes were investigated and implemented. The other primary goal of the study was to develop enhanced users manuals for Aardvark and Phantom. These manuals are intended to answer most questions for new users, as well as provide valuable detailed information for the experienced user. The existence of detailed user s manuals will enable new users to become proficient with the codes, as well as reducing the dependency of new users on the code authors. In order to achieve the

  8. Physics of Laser-driven plasma-based acceleration

    SciTech Connect

    Esarey, Eric; Schroeder, Carl B.

    2003-06-30

    The physics of plasma-based accelerators driven by short-pulse lasers is reviewed. This includes the laser wake-field accelerator, the plasma beat wave accelerator, the self-modulated laser wake-field accelerator, and plasma waves driven by multiple laser pulses. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse direction, electron dephasing, laser pulse energy depletion, as well as beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and plasmas with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Recent experimental results are summarized.

  9. Methods of geometrical integration in accelerator physics

    NASA Astrophysics Data System (ADS)

    Andrianov, S. N.

    2016-12-01

    In the paper we consider a method of geometric integration for a long evolution of the particle beam in cyclic accelerators, based on the matrix representation of the operator of particles evolution. This method allows us to calculate the corresponding beam evolution in terms of two-dimensional matrices including for nonlinear effects. The ideology of the geometric integration introduces in appropriate computational algorithms amendments which are necessary for preserving the qualitative properties of maps presented in the form of the truncated series generated by the operator of evolution. This formalism extends both on polarized and intense beams. Examples of practical applications are described.

  10. Status report on the 'Merging' of the Electron-Cloud Code POSINST with the 3-D Accelerator PIC CODE WARP

    SciTech Connect

    Vay, J.-L.; Furman, M.A.; Azevedo, A.W.; Cohen, R.H.; Friedman, A.; Grote, D.P.; Stoltz, P.H.

    2004-04-19

    We have integrated the electron-cloud code POSINST [1] with WARP [2]--a 3-D parallel Particle-In-Cell accelerator code developed for Heavy Ion Inertial Fusion--so that the two can interoperate. Both codes are run in the same process, communicate through a Python interpreter (already used in WARP), and share certain key arrays (so far, particle positions and velocities). Currently, POSINST provides primary and secondary sources of electrons, beam bunch kicks, a particle mover, and diagnostics. WARP provides the field solvers and diagnostics. Secondary emission routines are provided by the Tech-X package CMEE.

  11. Particle acceleration, transport and turbulence in cosmic and heliospheric physics

    NASA Technical Reports Server (NTRS)

    Matthaeus, W.

    1992-01-01

    In this progress report, the long term goals, recent scientific progress, and organizational activities are described. The scientific focus of this annual report is in three areas: first, the physics of particle acceleration and transport, including heliospheric modulation and transport, shock acceleration and galactic propagation and reacceleration of cosmic rays; second, the development of theories of the interaction of turbulence and large scale plasma and magnetic field structures, as in winds and shocks; third, the elucidation of the nature of magnetohydrodynamic turbulence processes and the role such turbulence processes might play in heliospheric, galactic, cosmic ray physics, and other space physics applications.

  12. Fluid Physics in a Fluctuating Acceleration Environment

    NASA Technical Reports Server (NTRS)

    Drolet, Francois; Vinals, Jorge

    1999-01-01

    Our program of research aims at developing a stochastic description of the residual acceleration field onboard spacecraft (g-jitter) to describe in quantitative detail its effect on fluid motion. Our main premise is that such a statistical description is necessary in those cases in which the characteristic time scales of the process under investigation are long compared with the correlation time of g-jitter. Although a clear separation between time scales makes this approach feasible, there remain several difficulties of practical nature: (i), g-jitter time series are not statistically stationary but rather show definite dependences on factors such as active or rest crew periods; (ii), it is very difficult to extract reliably the low frequency range of the power spectrum of the acceleration field. This range controls the magnitude of diffusive processes; and (iii), models used to date are Gaussian, but there is evidence that large amplitude disturbances occur much more frequently than a Gaussian distribution would predict. The lack of stationarity does not constitute a severe limitation in practice, since the intensity of the stochastic components changes very slowly during space missions (perhaps over times of the order of hours). A separate analysis of large amplitude disturbances has not been undertaken yet, but it does not seem difficult a priori to devise models that may describe this range better than a Gaussian distribution. The effect of low frequency components, on the other hand, is more difficult to ascertain, partly due to the difficulty associated with measuring them, and partly because they may be indistinguishable from slowly changing averages. This latter effect is further complicated by the lack of statistical stationarity of the time series. Recent work has focused on the effect of stochastic modulation on the onset of oscillatory instabilities as an example of resonant interaction between the driving acceleration and normal modes of the system

  13. High Energy Density Physics and Exotic Acceleration Schemes

    SciTech Connect

    Cowan, T.; Colby, E.; /SLAC

    2005-09-27

    The High Energy Density and Exotic Acceleration working group took as our goal to reach beyond the community of plasma accelerator research with its applications to high energy physics, to promote exchange with other disciplines which are challenged by related and demanding beam physics issues. The scope of the group was to cover particle acceleration and beam transport that, unlike other groups at AAC, are not mediated by plasmas or by electromagnetic structures. At this Workshop, we saw an impressive advancement from years past in the area of Vacuum Acceleration, for example with the LEAP experiment at Stanford. And we saw an influx of exciting new beam physics topics involving particle propagation inside of solid-density plasmas or at extremely high charge density, particularly in the areas of laser acceleration of ions, and extreme beams for fusion energy research, including Heavy-ion Inertial Fusion beam physics. One example of the importance and extreme nature of beam physics in HED research is the requirement in the Fast Ignitor scheme of inertial fusion to heat a compressed DT fusion pellet to keV temperatures by injection of laser-driven electron or ion beams of giga-Amp current. Even in modest experiments presently being performed on the laser-acceleration of ions from solids, mega-amp currents of MeV electrons must be transported through solid foils, requiring almost complete return current neutralization, and giving rise to a wide variety of beam-plasma instabilities. As keynote talks our group promoted Ion Acceleration (plenary talk by A. MacKinnon), which historically has grown out of inertial fusion research, and HIF Accelerator Research (invited talk by A. Friedman), which will require impressive advancements in space-charge-limited ion beam physics and in understanding the generation and transport of neutralized ion beams. A unifying aspect of High Energy Density applications was the physics of particle beams inside of solids, which is proving to

  14. DANTSYS: A diffusion accelerated neutral particle transport code system

    SciTech Connect

    Alcouffe, R.E.; Baker, R.S.; Brinkley, F.W.; Marr, D.R.; O`Dell, R.D.; Walters, W.F.

    1995-06-01

    The DANTSYS code package includes the following transport codes: ONEDANT, TWODANT, TWODANT/GQ, TWOHEX, and THREEDANT. The DANTSYS code package is a modular computer program package designed to solve the time-independent, multigroup discrete ordinates form of the boltzmann transport equation in several different geometries. The modular construction of the package separates the input processing, the transport equation solving, and the post processing (or edit) functions into distinct code modules: the Input Module, one or more Solver Modules, and the Edit Module, respectively. The Input and Edit Modules are very general in nature and are common to all the Solver Modules. The ONEDANT Solver Module contains a one-dimensional (slab, cylinder, and sphere), time-independent transport equation solver using the standard diamond-differencing method for space/angle discretization. Also included in the package are solver Modules named TWODANT, TWODANT/GQ, THREEDANT, and TWOHEX. The TWODANT Solver Module solves the time-independent two-dimensional transport equation using the diamond-differencing method for space/angle discretization. The authors have also introduced an adaptive weighted diamond differencing (AWDD) method for the spatial and angular discretization into TWODANT as an option. The TWOHEX Solver Module solves the time-independent two-dimensional transport equation on an equilateral triangle spatial mesh. The THREEDANT Solver Module solves the time independent, three-dimensional transport equation for XYZ and RZ{Theta} symmetries using both diamond differencing with set-to-zero fixup and the AWDD method. The TWODANT/GQ Solver Module solves the 2-D transport equation in XY and RZ symmetries using a spatial mesh of arbitrary quadrilaterals. The spatial differencing method is based upon the diamond differencing method with set-to-zero fixup with changes to accommodate the generalized spatial meshing.

  15. An introduction to the physics of high energy accelerators

    SciTech Connect

    Edwards, D.A.; Syphers, J.J.

    1993-01-01

    This book is an outgrowth of a course given by the authors at various universities and particle accelerator schools. It starts from the basic physics principles governing particle motion inside an accelerator, and leads to a full description of the complicated phenomena and analytical tools encountered in the design and operation of a working accelerator. The book covers acceleration and longitudinal beam dynamics, transverse motion and nonlinear perturbations, intensity dependent effects, emittance preservation methods and synchrotron radiation. These subjects encompass the core concerns of a high energy synchrotron. The authors apparently do not assume the reader has much previous knowledge about accelerator physics. Hence, they take great care to introduce the physical phenomena encountered and the concepts used to describe them. The mathematical formulae and derivations are deliberately kept at a level suitable for beginners. After mastering this course, any interested reader will not find it difficult to follow subjects of more current interests. Useful homework problems are provided at the end of each chapter. Many of the problems are based on actual activities associated with the design and operation of existing accelerators.

  16. Proceedings of the conference on computer codes and the linear accelerator community

    SciTech Connect

    Cooper, R.K.

    1990-07-01

    The conference whose proceedings you are reading was envisioned as the second in a series, the first having been held in San Diego in January 1988. The intended participants were those people who are actively involved in writing and applying computer codes for the solution of problems related to the design and construction of linear accelerators. The first conference reviewed many of the codes both extant and under development. This second conference provided an opportunity to update the status of those codes, and to provide a forum in which emerging new 3D codes could be described and discussed. The afternoon poster session on the second day of the conference provided an opportunity for extended discussion. All in all, this conference was felt to be quite a useful interchange of ideas and developments in the field of 3D calculations, parallel computation, higher-order optics calculations, and code documentation and maintenance for the linear accelerator community. A third conference is planned.

  17. Plasma wakefield acceleration studies using the quasi-static code WAKE

    SciTech Connect

    Jain, Neeraj; Palastro, John; Antonsen, T. M.; Mori, Warren B.; An, Weiming

    2015-02-15

    The quasi-static code WAKE [P. Mora and T. Antonsen, Phys. Plasmas 4, 217 (1997)] is upgraded to model the propagation of an ultra-relativistic charged particle beam through a warm background plasma in plasma wakefield acceleration. The upgraded code is benchmarked against the full particle-in-cell code OSIRIS [Hemker et al., Phys. Rev. Spec. Top. Accel. Beams 3, 061301 (2000)] and the quasi-static code QuickPIC [Huang et al., J. Comput. Phys. 217, 658 (2006)]. The effect of non-zero plasma temperature on the peak accelerating electric field is studied for a two bunch electron beam driver with parameters corresponding to the plasma wakefield acceleration experiments at Facilities for Accelerator Science and Experimental Test Beams. It is shown that plasma temperature does not affect the energy gain and spread of the accelerated particles despite suppressing the peak accelerating electric field. The role of plasma temperature in improving the numerical convergence of the electric field with the grid resolution is discussed.

  18. Development of improved methods for the LWR lattice physics code EPRI-CELL

    SciTech Connect

    Williams, M.L.; Wright, R.Q.; Barhen, J.

    1982-07-01

    A number of improvements have been made by ORNL to the lattice physics code EPRI-CELL (E-C) which is widely used by utilities for analysis of power reactors. The code modifications were made mainly in the thermal and epithermal routines and resulted in improved reactor physics approximations and more efficient running times. The improvements in the thermal flux calculation included implementation of a group-dependent rebalance procedure to accelerate the iterative process and a more rigorous calculation of interval-to-interval collision probabilities. The epithermal resonance shielding methods used in the code have been extensively studied to determine its major approximations and to examine the sensitivity of computed results to these approximations. The study has resulted in several improvements in the original methodology.

  19. Establishing confidence in complex physics codes: Art or science?

    SciTech Connect

    Trucano, T.

    1997-12-31

    The ALEGRA shock wave physics code, currently under development at Sandia National Laboratories and partially supported by the US Advanced Strategic Computing Initiative (ASCI), is generic to a certain class of physics codes: large, multi-application, intended to support a broad user community on the latest generation of massively parallel supercomputer, and in a continual state of formal development. To say that the author has ``confidence`` in the results of ALEGRA is to say something different than that he believes that ALEGRA is ``predictive.`` It is the purpose of this talk to illustrate the distinction between these two concepts. The author elects to perform this task in a somewhat historical manner. He will summarize certain older approaches to code validation. He views these methods as aiming to establish the predictive behavior of the code. These methods are distinguished by their emphasis on local information. He will conclude that these approaches are more art than science.

  20. Future Accelerator Challenges in Support of High-Energy Physics

    SciTech Connect

    Zisman, Michael S.; Zisman, M.S.

    2008-05-03

    Historically, progress in high-energy physics has largely been determined by development of more capable particle accelerators. This trend continues today with the imminent commissioning of the Large Hadron Collider at CERN, and the worldwide development effort toward the International Linear Collider. Looking ahead, there are two scientific areas ripe for further exploration--the energy frontier and the precision frontier. To explore the energy frontier, two approaches toward multi-TeV beams are being studied, an electron-positron linear collider based on a novel two-beam powering system (CLIC), and a Muon Collider. Work on the precision frontier involves accelerators with very high intensity, including a Super-BFactory and a muon-based Neutrino Factory. Without question, one of the most promising approaches is the development of muon-beam accelerators. Such machines have very high scientific potential, and would substantially advance the state-of-the-art in accelerator design. The challenges of the new generation of accelerators, and how these can be accommodated in the accelerator design, are described. To reap their scientific benefits, all of these frontier accelerators will require sophisticated instrumentation to characterize the beam and control it with unprecedented precision.

  1. Physics with post-accelerated beams at ISOLDE: nuclear reactions

    NASA Astrophysics Data System (ADS)

    Di Pietro, A.; Riisager, K.; Van Duppen, P.

    2017-04-01

    Nuclear-reaction studies have until now constituted a minor part of the physics program with post-accelerated beams at ISOLDE, mainly due to the maximum energy of REX-ISOLDE of around 3 MeV/u that limits reaction work to the mass region below A = 100. We give an overview of the current experimental status and of the physics results obtained so far. Finally, the improved conditions given by the HIE-ISOLDE upgrade are described.

  2. High-fidelity plasma codes for burn physics

    SciTech Connect

    Cooley, James; Graziani, Frank; Marinak, Marty; Murillo, Michael

    2016-10-19

    Accurate predictions of equation of state (EOS), ionic and electronic transport properties are of critical importance for high-energy-density plasma science. Transport coefficients inform radiation-hydrodynamic codes and impact diagnostic interpretation, which in turn impacts our understanding of the development of instabilities, the overall energy balance of burning plasmas, and the efficacy of self-heating from charged-particle stopping. Important processes include thermal and electrical conduction, electron-ion coupling, inter-diffusion, ion viscosity, and charged particle stopping. However, uncertainties in these coefficients are not well established. Fundamental plasma science codes, also called high-fidelity plasma codes, are a relatively recent computational tool that augments both experimental data and theoretical foundations of transport coefficients. This paper addresses the current status of HFPC codes and their future development, and the potential impact they play in improving the predictive capability of the multi-physics hydrodynamic codes used in HED design.

  3. Toward a physics design for NDCX-II, an ion accelerator for warm dense matter and HIF target physics studies

    SciTech Connect

    Friedman, A.; Barnard, J.J.; Briggs, R.J.; Davidson, R.C.; Dorf, M.; Grote, D.P.; Henestroza, E.; Lee, E.P.; Leitner, M.A.; Logan, B.G.; Sefkow, A.B.; Sharp, W.M.; Waldron, W.L.; Welch, D.R.; Yu, S.S.

    2008-08-01

    The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL), a collaborationof LBNL, LLNL, and PPPL, has achieved 60-fold pulse compression of ion beams on the Neutralized Drift Compression eXperiment (NDCX) at LBNL. In NDCX, a ramped voltage pulse from an induction cell imparts a velocity"tilt" to the beam; the beam's tail then catches up with its head in a plasma environment that provides neutralization. The HIFS-VNL's mission is to carry out studies of Warm Dense Matter (WDM) physics using ion beams as the energy source; an emerging thrust is basic target physics for heavy ion-driven Inertial Fusion Energy (IFE). These goals require an improved platform, labeled NDCX-II. Development of NDCX-II at modest cost was recently enabled by the availability of induction cells and associated hardware from the decommissioned Advanced Test Accelerator (ATA) facility at LLNL. Our initial physics design concept accelerates a ~;;30 nC pulse of Li+ ions to ~;;3 MeV, then compresses it to ~;;1 ns while focusing it onto a mm-scale spot. It uses the ATA cells themselves (with waveforms shaped by passive circuits) to impart the final velocity tilt; smart pulsers provide small corrections. The ATA accelerated electrons; acceleration of non-relativistic ions involves more complex beam dynamics both transversely and longitudinally. We are using analysis, an interactive one-dimensional kinetic simulation model, and multidimensional Warp-code simulations to develop the NDCX-II accelerator section. Both LSP and Warp codes are being applied to the beam dynamics in the neutralized drift and final focus regions, and the plasma injection process. The status of this effort is described.

  4. Toward a physics design for NDCX II, an ion accelerator for warm dense matter and HIF target physics studies

    SciTech Connect

    Friedman, A; Barnard, J J; Briggs, R J; Davidson, R C; Dorf, M; Grote, D P; Henestroza, E; Lee, E P; Leitner, M A; Logan, B G; Sefkow, A B; Sharp, W M; Waldron, W L; Welch, D R; Yu, S S

    2008-07-30

    The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL), a collaboration of LBNL, LLNL, and PPPL, has achieved 60-fold pulse compression of ion beams on the Neutralized Drift Compression eXperiment (NDCX) at LBNL. In NDCX, a ramped voltage pulse from an induction cell imparts a velocity 'tilt' to the beam; the beam's tail then catches up with its head in a plasma environment that provides neutralization. The HIFS-VNL's mission is to carry out studies of warm dense matter (WDM) physics using ion beams as the energy source; an emerging thrust is basic target physics for heavy ion-driven inertial fusion energy (IFE). These goals require an improved platform, labeled NDCX-II. Development of NDCX-II at modest cost was recently enabled by the availability of induction cells and associated hardware from the decommissioned advanced test accelerator (ATA) facility at LLNL. Our initial physics design concept accelerates an {approx} 30 nC pulse of Li{sup +} ions to {approx} 3 MeV, then compresses it to {approx} 1 ns while focusing it onto a mm-scale spot. It uses the ATA cells themselves (with waveforms shaped by passive circuits) to impart the final velocity tilt; smart pulsers provide small corrections. The ATA accelerated electrons; acceleration of non-relativistic ions involves more complex beam dynamics both transversely and longitudinally. We are using an interactive one-dimensional kinetic simulation model and multidimensional Warp-code simulations to develop the NDCX-II accelerator section. Both LSP and Warp codes are being applied to the beam dynamics in the neutralized drift and final focus regions, and the plasma injection process. The status of this effort is described.

  5. From Particle Physics to Astroparticle Physics: Proton Decay and the Rise of Non-accelerator Physics

    NASA Astrophysics Data System (ADS)

    Meyer, Hinrich

    The search for proton decay was motivated by simple questions about the content of the observable universe. Why is matter so stable and why do we not see antimatter of primordial origin? The symmetry of the standard model of particle physics would have required that matter and antimatter annihilated in the early universe. In 1968, Sacharov showed that the matter-antimatter asymmetry could have formed in a state of thermal non-equilibrium of the universe, as given in big bang cosmology, together with the well-confirmed C and CP violations, and proton decay. The latter phenomenon could be only investigated in large none-accelerator experiments. The SU(5) extension of the standard model implied a proton lifetime of about 1029 years. With detectors consisting of 1 000 tons of matter and located deep under the Earth surface, such as the French-German Fréjus iron-calorimeter, in the mid 1980s one expected to detect several proton decays per year. Here, we report on the way leading from accelerator laboratories to underground physics, which paradoxically enough turned out to studying cosmic rays. There has not been any evidence for the instability of protons, and lifetime limits of more than 1034 years have been obtained. However, great progress in particle physics and in the physics of cosmic rays could be achieved with neutrinos.

  6. Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities

    SciTech Connect

    Lee, Lie-Quan; Li, Zenghai; Ng, Cho; Ko, Kwok; /SLAC

    2009-03-04

    Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, cavities with imperfectly conducting surfaces, and cavities with waveguide coupling. We will discuss the parallel algorithms for solving those eigenvalue problems and demonstrate modeling of accelerator cavities through different examples.

  7. Recent improvements of reactor physics codes in MHI

    SciTech Connect

    Kosaka, Shinya Yamaji, Kazuya; Kirimura, Kazuki; Kamiyama, Yohei; Matsumoto, Hideki

    2015-12-31

    This paper introduces recent improvements for reactor physics codes in Mitsubishi Heavy Industries, Ltd(MHI). MHI has developed a new neutronics design code system Galaxy/Cosmo-S(GCS) for PWR core analysis. After TEPCO’s Fukushima Daiichi accident, it is required to consider design extended condition which has not been covered explicitly by the former safety licensing analyses. Under these circumstances, MHI made some improvements for GCS code system. A new resonance calculation model of lattice physics code and homogeneous cross section representative model for core simulator have been developed to apply more wide range core conditions corresponding to severe accident status such like anticipated transient without scram (ATWS) analysis and criticality evaluation of dried-up spent fuel pit. As a result of these improvements, GCS code system has very wide calculation applicability with good accuracy for any core conditions as far as fuel is not damaged. In this paper, the outline of GCS code system is described briefly and recent relevant development activities are presented.

  8. Health physics manual of good practices for accelerator facilities

    SciTech Connect

    Casey, W.R.; Miller, A.J.; McCaslin, J.B.; Coulson, L.V.

    1988-04-01

    It is hoped that this manual will serve both as a teaching aid as well as a useful adjunct for program development. In the context of application, this manual addresses good practices that should be observed by management, staff, and designers since the achievement of a good radiation program indeed involves a combined effort. Ultimately, radiation safety and good work practices become the personal responsibility of the individual. The practices presented in this manual are not to be construed as mandatory rather they are to be used as appropriate for the specific case in the interest of radiation safety. As experience is accrued and new data obtained in the application of this document, ONS will update the guidance to assure that at any given time the guidance reflects optimum performance consistent with current technology and practice.The intent of this guide therefore is to: define common health physics problems at accelerators; recommend suitable methods of identifying, evaluating, and managing accelerator health physics problems; set out the established safety practices at DOE accelerators that have been arrived at by consensus and, where consensus has not yet been reached, give examples of safe practices; introduce the technical literature in the accelerator health physics field; and supplement the regulatory documents listed in Appendix D. Many accelerator health physics problems are no different than those at other kinds of facilities, e.g., ALARA philosophy, instrument calibration, etc. These problems are touched on very lightly or not at all. Similarly, this document does not cover other hazards such as electrical shock, toxic materials, etc. This does not in any way imply that these problems are not serious. 160 refs.

  9. Better physical activity classification using smartphone acceleration sensor.

    PubMed

    Arif, Muhammad; Bilal, Mohsin; Kattan, Ahmed; Ahamed, S Iqbal

    2014-09-01

    Obesity is becoming one of the serious problems for the health of worldwide population. Social interactions on mobile phones and computers via internet through social e-networks are one of the major causes of lack of physical activities. For the health specialist, it is important to track the record of physical activities of the obese or overweight patients to supervise weight loss control. In this study, acceleration sensor present in the smartphone is used to monitor the physical activity of the user. Physical activities including Walking, Jogging, Sitting, Standing, Walking upstairs and Walking downstairs are classified. Time domain features are extracted from the acceleration data recorded by smartphone during different physical activities. Time and space complexity of the whole framework is done by optimal feature subset selection and pruning of instances. Classification results of six physical activities are reported in this paper. Using simple time domain features, 99 % classification accuracy is achieved. Furthermore, attributes subset selection is used to remove the redundant features and to minimize the time complexity of the algorithm. A subset of 30 features produced more than 98 % classification accuracy for the six physical activities.

  10. Multipactor Physics, Acceleration, and Breakdown in Dielectric-Loaded Accelerating Structures

    SciTech Connect

    Fischer, Richard P.; Gold, Steven H.

    2016-07-01

    The objective of this 3-year program is to study the physics issues associated with rf acceleration in dielectric-loaded accelerating (DLA) structures, with a focus on the key issue of multipactor loading, which has been found to cause very significant rf power loss in DLA structures whenever the rf pulsewidth exceeds the multipactor risetime (~10 ns). The experiments are carried out in the X-band magnicon laboratory at the Naval Research Laboratory (NRL) in collaboration with Argonne National Laboratory (ANL) and Euclid Techlabs LLC, who develop the test structures with support from the DoE SBIR program. There are two main elements in the research program: (1) high-power tests of DLA structures using the magnicon output (20 MW @11.4 GHz), and (2) tests of electron acceleration in DLA structures using relativistic electrons from a compact X-band accelerator. The work during this period has focused on a study of the use of an axial magnetic field to suppress multipactor in DLA structures, with several new high power tests carried out at NRL, and on preparation of the accelerator for the electron acceleration experiments.

  11. Physical-layer network coding in coherent optical OFDM systems.

    PubMed

    Guan, Xun; Chan, Chun-Kit

    2015-04-20

    We present the first experimental demonstration and characterization of the application of optical physical-layer network coding in coherent optical OFDM systems. It combines two optical OFDM frames to share the same link so as to enhance system throughput, while individual OFDM frames can be recovered with digital signal processing at the destined node.

  12. Simulation of Laser Wake Field Acceleration using a 2.5D PIC Code

    SciTech Connect

    An, W. M.; Hua, J. F.; Huang, W. H.; Tang, Ch. X.; Lin, Y. Z.

    2006-11-27

    A 2.5D PIC simulation code is developed to study the LWFA( Laser WakeField Acceleration ). The electron self-injection and the generation of mono-energetic electron beam in LWFA is briefly discussed through the simulation. And the experiment of this year at SILEX-I laser facility is also introduced.

  13. Radiation Protection Studies for Medical Particle Accelerators using Fluka Monte Carlo Code.

    PubMed

    Infantino, Angelo; Cicoria, Gianfranco; Lucconi, Giulia; Pancaldi, Davide; Vichi, Sara; Zagni, Federico; Mostacci, Domiziano; Marengo, Mario

    2016-11-24

    Radiation protection (RP) in the use of medical cyclotrons involves many aspects both in the routine use and for the decommissioning of a site. Guidelines for site planning and installation, as well as for RP assessment, are given in international documents; however, the latter typically offer analytic methods of calculation of shielding and materials activation, in approximate or idealised geometry set-ups. The availability of Monte Carlo (MC) codes with accurate up-to-date libraries for transport and interaction of neutrons and charged particles at energies below 250 MeV, together with the continuously increasing power of modern computers, makes the systematic use of simulations with realistic geometries possible, yielding equipment and site-specific evaluation of the source terms, shielding requirements and all quantities relevant to RP at the same time. In this work, the well-known FLUKA MC code was used to simulate different aspects of RP in the use of biomedical accelerators, particularly for the production of medical radioisotopes. In the context of the Young Professionals Award, held at the IRPA 14 conference, only a part of the complete work is presented. In particular, the simulation of the GE PETtrace cyclotron (16.5 MeV) installed at S. Orsola-Malpighi University Hospital evaluated the effective dose distribution around the equipment; the effective number of neutrons produced per incident proton and their spectral distribution; the activation of the structure of the cyclotron and the vault walls; the activation of the ambient air, in particular the production of (41)Ar. The simulations were validated, in terms of physical and transport parameters to be used at the energy range of interest, through an extensive measurement campaign of the neutron environmental dose equivalent using a rem-counter and TLD dosemeters. The validated model was then used in the design and the licensing request of a new Positron Emission Tomography facility.

  14. Production Level CFD Code Acceleration for Hybrid Many-Core Architectures

    NASA Technical Reports Server (NTRS)

    Duffy, Austen C.; Hammond, Dana P.; Nielsen, Eric J.

    2012-01-01

    In this work, a novel graphics processing unit (GPU) distributed sharing model for hybrid many-core architectures is introduced and employed in the acceleration of a production-level computational fluid dynamics (CFD) code. The latest generation graphics hardware allows multiple processor cores to simultaneously share a single GPU through concurrent kernel execution. This feature has allowed the NASA FUN3D code to be accelerated in parallel with up to four processor cores sharing a single GPU. For codes to scale and fully use resources on these and the next generation machines, codes will need to employ some type of GPU sharing model, as presented in this work. Findings include the effects of GPU sharing on overall performance. A discussion of the inherent challenges that parallel unstructured CFD codes face in accelerator-based computing environments is included, with considerations for future generation architectures. This work was completed by the author in August 2010, and reflects the analysis and results of the time.

  15. A Hilbert-Vlasov code for the study of high-frequency plasma beatwave accelerator

    SciTech Connect

    Ghizzo, A.; Bertrand, P.; Begue, M.L.; Johnston, T.W.; Shoucri, M.

    1996-04-01

    High-frequency beatwave simulations relevant to the University of California at Los Angeles (UCLA) experiment with relativistic eulerian hybrid Vlasov code are presented. These Hilbert-Vlasov simulations revealed a rich variety of phenomena associated with the fast particle dynamics induced by beatwave experiment for a high ratio of driver frequency to plasma frequency {omega}{sub pump}/{omega}{sub pump} {approx} 33. The present model allows one to extend detailed modeling to frequency ratios greater than the current practical maximum of 10 or so, for Vlasov or particle-in-cell (PIC) codes, by replacing the Maxwell equations by mode equations for the electromagnetic Vlasov code. Numerical results, including beat frequency chirping (i.e., pump frequency linearly decreasing with time), show that the amplitude limit due to relativistic detuning can be enhanced with accelerated particles up to the ultrarelativistic energies with a high-acceleration gradient of more than 25 GeV/m.

  16. Methods used in WARP3d, a three-dimensional PIC/accelerator code

    SciTech Connect

    Grote, D.P.; Friedman, A.; Haber, I.

    1997-02-28

    WARP-3d(1,2), a three-dimensional PIC/accelerator code, has been developed over several years and has played a major role in the design and analysis of space-charge dominated beam experiments being carried out by the heavy-ion fusion programs at LLNL and LBNL. Major features of the code will be reviewed, including: residence corrections which allow large timesteps to be taken, electrostatic field solution with subgrid scale resolution of internal conductor boundaries, and a beat beam algorithm. Emphasis will be placed on new features and capabilities of the code, which include: a port to parallel processing environments, space-charge limited injection, and the linking of runs covering different sections of an accelerator. Representative applications in which the new features and capabilities are used will be presented along with the important results.

  17. Innovative applications of genetic algorithms to problems in accelerator physics

    NASA Astrophysics Data System (ADS)

    Hofler, Alicia; Terzić, Balša; Kramer, Matthew; Zvezdin, Anton; Morozov, Vasiliy; Roblin, Yves; Lin, Fanglei; Jarvis, Colin

    2013-01-01

    The genetic algorithm (GA) is a powerful technique that implements the principles nature uses in biological evolution to optimize a multidimensional nonlinear problem. The GA works especially well for problems with a large number of local extrema, where traditional methods (such as conjugate gradient, steepest descent, and others) fail or, at best, underperform. The field of accelerator physics, among others, abounds with problems which lend themselves to optimization via GAs. In this paper, we report on the successful application of GAs in several problems related to the existing Continuous Electron Beam Accelerator Facility nuclear physics machine, the proposed Medium-energy Electron-Ion Collider at Jefferson Lab, and a radio frequency gun-based injector. These encouraging results are a step forward in optimizing accelerator design and provide an impetus for application of GAs to other problems in the field. To that end, we discuss the details of the GAs used, include a newly devised enhancement which leads to improved convergence to the optimum, and make recommendations for future GA developments and accelerator applications.

  18. What accelerator mass spectrometry can do for solar physics

    NASA Astrophysics Data System (ADS)

    Newkirk, Gordon

    1984-11-01

    We review some of the empirical aspects of the solar magnetic activity and the convective dynamo models developed to account for the magnetic cycle. Alternative hypotheses which have recently emerged are sketched. Possible applications of accelerator mass spectrometry to solar physics and the important questions that proxy data on past solar activity might answer are evaluated. The National Center for Atmospheric Research is sponsored by the National Science Foundation.

  19. Accelerator physics in ERL based polarized electron ion collider

    SciTech Connect

    Hao, Yue

    2015-05-03

    This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

  20. Accelerator Physics Challenges for the NSLS-II Project

    SciTech Connect

    Krinsky,S.

    2009-05-04

    The NSLS-II is an ultra-bright synchrotron light source based upon a 3-GeV storage ring with a 30-cell (15 super-period) double-bend-achromat lattice with damping wigglers used to lower the emittance below 1 nm. In this paper, we discuss the accelerator physics challenges for the design including: optimization of dynamic aperture; estimation of Touschek lifetime; achievement of required orbit stability; and analysis of ring impedance and collective effects.

  1. Code System for Reactor Physics and Fuel Cycle Simulation.

    SciTech Connect

    TEUCHERT, E.

    1999-04-21

    Version 00 VSOP94 (Very Superior Old Programs) is a system of codes linked together for the simulation of reactor life histories. It comprises neutron cross section libraries and processing routines, repeated neutron spectrum evaluation, 2-D diffusion calculation based on neutron flux synthesis with depletion and shut-down features, in-core and out-of-pile fuel management, fuel cycle cost analysis, and thermal hydraulics (at present restricted to Pebble Bed HTRs). Various techniques have been employed to accelerate the iterative processes and to optimize the internal data transfer. The code system has been used extensively for comparison studies of reactors, their fuel cycles, and related detailed features. In addition to its use in research and development work for the High Temperature Reactor, the system has been applied successfully to Light Water and Heavy Water Reactors.

  2. Enhanced Verification Test Suite for Physics Simulation Codes

    SciTech Connect

    Kamm, J R; Brock, J S; Brandon, S T; Cotrell, D L; Johnson, B; Knupp, P; Rider, W; Trucano, T; Weirs, V G

    2008-10-10

    This document discusses problems with which to augment, in quantity and in quality, the existing tri-laboratory suite of verification problems used by Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and Sandia National Laboratories (SNL). The purpose of verification analysis is demonstrate whether the numerical results of the discretization algorithms in physics and engineering simulation codes provide correct solutions of the corresponding continuum equations. The key points of this document are: (1) Verification deals with mathematical correctness of the numerical algorithms in a code, while validation deals with physical correctness of a simulation in a regime of interest. This document is about verification. (2) The current seven-problem Tri-Laboratory Verification Test Suite, which has been used for approximately five years at the DOE WP laboratories, is limited. (3) Both the methodology for and technology used in verification analysis have evolved and been improved since the original test suite was proposed. (4) The proposed test problems are in three basic areas: (a) Hydrodynamics; (b) Transport processes; and (c) Dynamic strength-of-materials. (5) For several of the proposed problems we provide a 'strong sense verification benchmark', consisting of (i) a clear mathematical statement of the problem with sufficient information to run a computer simulation, (ii) an explanation of how the code result and benchmark solution are to be evaluated, and (iii) a description of the acceptance criterion for simulation code results. (6) It is proposed that the set of verification test problems with which any particular code be evaluated include some of the problems described in this document. Analysis of the proposed verification test problems constitutes part of a necessary--but not sufficient--step that builds confidence in physics and engineering simulation codes. More complicated test cases, including physics models of greater

  3. A Comparison Between GATE and MCNPX Monte Carlo Codes in Simulation of Medical Linear Accelerator

    PubMed Central

    Sadoughi, Hamid-Reza; Nasseri, Shahrokh; Momennezhad, Mahdi; Sadeghi, Hamid-Reza; Bahreyni-Toosi, Mohammad-Hossein

    2014-01-01

    Radiotherapy dose calculations can be evaluated by Monte Carlo (MC) simulations with acceptable accuracy for dose prediction in complicated treatment plans. In this work, Standard, Livermore and Penelope electromagnetic (EM) physics packages of GEANT4 application for tomographic emission (GATE) 6.1 were compared versus Monte Carlo N-Particle eXtended (MCNPX) 2.6 in simulation of 6 MV photon Linac. To do this, similar geometry was used for the two codes. The reference values of percentage depth dose (PDD) and beam profiles were obtained using a 6 MV Elekta Compact linear accelerator, Scanditronix water phantom and diode detectors. No significant deviations were found in PDD, dose profile, energy spectrum, radial mean energy and photon radial distribution, which were calculated by Standard and Livermore EM models and MCNPX, respectively. Nevertheless, the Penelope model showed an extreme difference. Statistical uncertainty in all the simulations was <1%, namely 0.51%, 0.27%, 0.27% and 0.29% for PDDs of 10 cm2× 10 cm2 filed size, for MCNPX, Standard, Livermore and Penelope models, respectively. Differences between spectra in various regions, in radial mean energy and in photon radial distribution were due to different cross section and stopping power data and not the same simulation of physics processes of MCNPX and three EM models. For example, in the Standard model, the photoelectron direction was sampled from the Gavrila-Sauter distribution, but the photoelectron moved in the same direction of the incident photons in the photoelectric process of Livermore and Penelope models. Using the same primary electron beam, the Standard and Livermore EM models of GATE and MCNPX showed similar output, but re-tuning of primary electron beam is needed for the Penelope model. PMID:24696804

  4. A Comparison Between GATE and MCNPX Monte Carlo Codes in Simulation of Medical Linear Accelerator.

    PubMed

    Sadoughi, Hamid-Reza; Nasseri, Shahrokh; Momennezhad, Mahdi; Sadeghi, Hamid-Reza; Bahreyni-Toosi, Mohammad-Hossein

    2014-01-01

    Radiotherapy dose calculations can be evaluated by Monte Carlo (MC) simulations with acceptable accuracy for dose prediction in complicated treatment plans. In this work, Standard, Livermore and Penelope electromagnetic (EM) physics packages of GEANT4 application for tomographic emission (GATE) 6.1 were compared versus Monte Carlo N-Particle eXtended (MCNPX) 2.6 in simulation of 6 MV photon Linac. To do this, similar geometry was used for the two codes. The reference values of percentage depth dose (PDD) and beam profiles were obtained using a 6 MV Elekta Compact linear accelerator, Scanditronix water phantom and diode detectors. No significant deviations were found in PDD, dose profile, energy spectrum, radial mean energy and photon radial distribution, which were calculated by Standard and Livermore EM models and MCNPX, respectively. Nevertheless, the Penelope model showed an extreme difference. Statistical uncertainty in all the simulations was <1%, namely 0.51%, 0.27%, 0.27% and 0.29% for PDDs of 10 cm(2)× 10 cm(2) filed size, for MCNPX, Standard, Livermore and Penelope models, respectively. Differences between spectra in various regions, in radial mean energy and in photon radial distribution were due to different cross section and stopping power data and not the same simulation of physics processes of MCNPX and three EM models. For example, in the Standard model, the photoelectron direction was sampled from the Gavrila-Sauter distribution, but the photoelectron moved in the same direction of the incident photons in the photoelectric process of Livermore and Penelope models. Using the same primary electron beam, the Standard and Livermore EM models of GATE and MCNPX showed similar output, but re-tuning of primary electron beam is needed for the Penelope model.

  5. Physics and engineering design of the accelerator and electron dump for SPIDER

    NASA Astrophysics Data System (ADS)

    Agostinetti, P.; Antoni, V.; Cavenago, M.; Chitarin, G.; Marconato, N.; Marcuzzi, D.; Pilan, N.; Serianni, G.; Sonato, P.; Veltri, P.; Zaccaria, P.

    2011-06-01

    The ITER Neutral Beam Test Facility (PRIMA) is planned to be built at Consorzio RFX (Padova, Italy). PRIMA includes two experimental devices: a full size ion source with low voltage extraction called SPIDER and a full size neutral beam injector at full beam power called MITICA. SPIDER is the first experimental device to be built and operated, aiming at testing the extraction of a negative ion beam (made of H- and in a later stage D- ions) from an ITER size ion source. The main requirements of this experiment are a H-/D- extracted current density larger than 355/285 A m-2, an energy of 100 keV and a pulse duration of up to 3600 s. Several analytical and numerical codes have been used for the design optimization process, some of which are commercial codes, while some others were developed ad hoc. The codes are used to simulate the electrical fields (SLACCAD, BYPO, OPERA), the magnetic fields (OPERA, ANSYS, COMSOL, PERMAG), the beam aiming (OPERA, IRES), the pressure inside the accelerator (CONDUCT, STRIP), the stripping reactions and transmitted/dumped power (EAMCC), the operating temperature, stress and deformations (ALIGN, ANSYS) and the heat loads on the electron dump (ED) (EDAC, BACKSCAT). An integrated approach, taking into consideration at the same time physics and engineering aspects, has been adopted all along the design process. Particular care has been taken in investigating the many interactions between physics and engineering aspects of the experiment. According to the 'robust design' philosophy, a comprehensive set of sensitivity analyses was performed, in order to investigate the influence of the design choices on the most relevant operating parameters. The design of the SPIDER accelerator, here described, has been developed in order to satisfy with reasonable margin all the requirements given by ITER, from the physics and engineering points of view. In particular, a new approach to the compensation of unwanted beam deflections inside the accelerator

  6. Benchmarking the codes VORPAL, OSIRIS, and QuickPIC with Laser Wakefield Acceleration Simulations

    SciTech Connect

    Paul, K.; Bruhwiler, D. L.; Cowan, B.; Cary, J. R.; Huang, C.; Mori, W. B.; Tsung, F. S.; Cormier-Michel, E.; Geddes, C. G. R.; Esarey, E.; Fonseca, R. A.; Martins, S. F.; Silva, L. O.

    2009-01-22

    Three-dimensional laser wakefield acceleration (LWFA) simulations have recently been performed to benchmark the commonly used particle-in-cell (PIC) codes VORPAL, OSIRIS, and QuickPIC. The simulations were run in parallel on over 100 processors, using parameters relevant to LWFA with ultra-short Ti-Sapphire laser pulses propagating in hydrogen gas. Both first-order and second-order particle shapes were employed. We present the results of this benchmarking exercise, and show that accelerating gradients from full PIC agree for all values of a{sub 0} and that full and reduced PIC agree well for values of a{sub 0} approaching 4.

  7. Developing The Physics Desing for NDCS-II, A Unique Pulse-Compressing Ion Accelerator

    SciTech Connect

    Friedman, A; Barnard, J J; Cohen, R H; Grote, D P; Lund, S M; Sharp, W M; Faltens, A; Henestroza, E; Jung, J; Kwan, J W; Lee, E P; Leitner, M A; Logan, B G; Vay, J -; Waldron, W L; Davidson, R C; Dorf, M; Gilson, E P; Kaganovich, I

    2009-09-24

    The Heavy Ion Fusion Science Virtual National Laboratory (a collaboration of LBNL, LLNL, and PPPL) is using intense ion beams to heat thin foils to the 'warm dense matter' regime at {approx}< 1 eV, and is developing capabilities for studying target physics relevant to ion-driven inertial fusion energy. The need for rapid target heating led to the development of plasma-neutralized pulse compression, with current amplification factors exceeding 50 now routine on the Neutralized Drift Compression Experiment (NDCX). Construction of an improved platform, NDCX-II, has begun at LBNL with planned completion in 2012. Using refurbished induction cells from the Advanced Test Accelerator at LLNL, NDCX-II will compress a {approx}500 ns pulse of Li{sup +} ions to {approx} 1 ns while accelerating it to 3-4 MeV over {approx} 15 m. Strong space charge forces are incorporated into the machine design at a fundamental level. We are using analysis, an interactive 1D PIC code (ASP) with optimizing capabilities and centroid tracking, and multi-dimensional Warpcode PIC simulations, to develop the NDCX-II accelerator. This paper describes the computational models employed, and the resulting physics design for the accelerator.

  8. DEVELOPING THE PHYSICS DESIGN FOR NDCX-II, A UNIQUE PULSE-COMPRESSING ION ACCELERATOR

    SciTech Connect

    Friedman, A.; Barnard, J. J.; Cohen, R. H.; Grote, D. P.; Lund, S. M.; Sharp, W. M.; Faltens, A.; Henestroza, E.; Jung, J-Y.; Kwan, J. W.; Lee, E. P.; Leitner, M. A.; Logan, B. G.; Vay, J.-L.; Waldron, W. L.; Davidson, R.C.; Dorf, M.; Gilson, E.P.; Kaganovich, I.

    2009-07-20

    The Heavy Ion Fusion Science Virtual National Laboratory(a collaboration of LBNL, LLNL, and PPPL) is using intense ion beams to heat thin foils to the"warm dense matter" regime at<~;; 1 eV, and is developing capabilities for studying target physics relevant to ion-driven inertial fusion energy. The need for rapid target heating led to the development of plasma-neutralized pulse compression, with current amplification factors exceeding 50 now routine on the Neutralized Drift Compression Experiment (NDCX). Construction of an improved platform, NDCX-II, has begun at LBNL with planned completion in 2012. Using refurbished induction cells from the Advanced Test Accelerator at LLNL, NDCX-II will compress a ~;;500 ns pulse of Li+ ions to ~;;1 ns while accelerating it to 3-4 MeV over ~;;15 m. Strong space charge forces are incorporated into the machine design at a fundamental level. We are using analysis, an interactive 1D PIC code (ASP) with optimizing capabilities and centroid tracking, and multi-dimensional Warpcode PIC simulations, to develop the NDCX-II accelerator. This paper describes the computational models employed, and the resulting physics design for the accelerator.

  9. GAMER: A GRAPHIC PROCESSING UNIT ACCELERATED ADAPTIVE-MESH-REFINEMENT CODE FOR ASTROPHYSICS

    SciTech Connect

    Schive, H.-Y.; Tsai, Y.-C.; Chiueh Tzihong

    2010-02-01

    We present the newly developed code, GPU-accelerated Adaptive-MEsh-Refinement code (GAMER), which adopts a novel approach in improving the performance of adaptive-mesh-refinement (AMR) astrophysical simulations by a large factor with the use of the graphic processing unit (GPU). The AMR implementation is based on a hierarchy of grid patches with an oct-tree data structure. We adopt a three-dimensional relaxing total variation diminishing scheme for the hydrodynamic solver and a multi-level relaxation scheme for the Poisson solver. Both solvers have been implemented in GPU, by which hundreds of patches can be advanced in parallel. The computational overhead associated with the data transfer between the CPU and GPU is carefully reduced by utilizing the capability of asynchronous memory copies in GPU, and the computing time of the ghost-zone values for each patch is diminished by overlapping it with the GPU computations. We demonstrate the accuracy of the code by performing several standard test problems in astrophysics. GAMER is a parallel code that can be run in a multi-GPU cluster system. We measure the performance of the code by performing purely baryonic cosmological simulations in different hardware implementations, in which detailed timing analyses provide comparison between the computations with and without GPU(s) acceleration. Maximum speed-up factors of 12.19 and 10.47 are demonstrated using one GPU with 4096{sup 3} effective resolution and 16 GPUs with 8192{sup 3} effective resolution, respectively.

  10. Physics design of the HNB accelerator for ITER

    NASA Astrophysics Data System (ADS)

    de Esch, H. P. L.; Kashiwagi, M.; Taniguchi, M.; Inoue, T.; Serianni, G.; Agostinetti, P.; Chitarin, G.; Marconato, N.; Sartori, E.; Sonato, P.; Veltri, P.; Pilan, N.; Aprile, D.; Fonnesu, N.; Antoni, V.; Singh, M. J.; Hemsworth, R. S.; Cavenago, M.

    2015-09-01

    The physics design of the accelerator for the heating neutral beamline on ITER is now finished and this paper describes the considerations and choices which constitute the basis of this design. Equal acceleration gaps of 88 mm have been chosen to improve the voltage holding capability while keeping the beam divergence low. Kerbs (metallic plates around groups of apertures, attached to the downstream surface of the grids) are used to compensate for the beamlet-beamlet interaction and to point the beamlets in the right direction. A novel magnetic configuration is employed to compensate for the beamlet deflection caused by the electron suppression magnets in the extraction grid. A combination of long-range and short-range magnetic fields is used to reduce electron leakage between the grids and limit the transmitted electron power to below 800 kW.

  11. Operational Radiation Protection in High-Energy Physics Accelerators

    SciTech Connect

    Rokni, S.H.; Fasso, A.; Liu, J.C.; /SLAC

    2012-04-03

    An overview of operational radiation protection (RP) policies and practices at high-energy electron and proton accelerators used for physics research is presented. The different radiation fields and hazards typical of these facilities are described, as well as access control and radiation control systems. The implementation of an operational RP programme is illustrated, covering area and personnel classification and monitoring, radiation surveys, radiological environmental protection, management of induced radioactivity, radiological work planning and control, management of radioactive materials and wastes, facility dismantling and decommissioning, instrumentation and training.

  12. Status of Continuum Edge Gyrokinetic Code Physics Development

    SciTech Connect

    Xu, X Q; Xiong, Z; Dorr, M R; Hittinger, J A; Kerbel, G D; Nevins, W M; Cohen, B I; Cohen, R H

    2005-05-31

    We are developing an edge gyro-kinetic continuum simulation code to study the boundary plasma over a region extending from inside the H-mode pedestal across the separatrix to the divertor plates. A 4-D ({psi}, {theta}, {epsilon}, {mu}) version of this code is presently being implemented, en route to a full 5-D version. A set of gyrokinetic equations[1] are discretized on computational grid which incorporates X-point divertor geometry. The present implementation is a Method of Lines approach where the phase-space derivatives are discretized with finite differences and implicit backwards differencing formulas are used to advance the system in time. A fourth order upwinding algorithm is used for particle cross-field drifts, parallel streaming, and acceleration. Boundary conditions at conducting material surfaces are implemented on the plasma side of the sheath. The Poisson-like equation is solved using GMRES with multi-grid preconditioner from HYPRE. A nonlinear Fokker-Planck collision operator from STELLA[2] in ({nu}{sub {parallel}},{nu}{sub {perpendicular}}) has been streamlined and integrated into the gyro-kinetic package using the same implicit Newton-Krylov solver and interpolating F and dF/dt|{sub coll} to/from ({epsilon}, {mu}) space. With our 4D code we compute the ion thermal flux, ion parallel velocity, self-consistent electric field, and geo-acoustic oscillations, which we compare with standard neoclassical theory for core plasma parameters; and we study the transition from collisional to collisionless end-loss. In the real X-point geometry, we find that the particles are trapped near outside midplane and in the X-point regions due to the magnetic configurations. The sizes of banana orbits are comparable to the pedestal width and/or the SOL width for energetic trapped particles. The effect of the real X-point geometry and edge plasma conditions on standard neoclassical theory will be evaluated, including a comparison of our 4D code with other kinetic

  13. Theoretical atomic physics code development I: CATS: Cowan Atomic Structure Code

    SciTech Connect

    Abdallah, J. Jr.; Clark, R.E.H.; Cowan, R.D.

    1988-12-01

    An adaptation of R.D. Cowan's Atomic Structure program, CATS, has been developed as part of the Theoretical Atomic Physics (TAPS) code development effort at Los Alamos. CATS has been designed to be easy to run and to produce data files that can interface with other programs easily. The CATS produced data files currently include wave functions, energy levels, oscillator strengths, plane-wave-Born electron-ion collision strengths, photoionization cross sections, and a variety of other quantities. This paper describes the use of CATS. 10 refs.

  14. Physics and engineering studies on the MITICA accelerator: comparison among possible design solutions

    SciTech Connect

    Agostinetti, P.; Antoni, V.; Chitarin, G.; Pilan, N.; Marcuzzi, D.; Serianni, G.; Veltri, P.; Cavenago, M.

    2011-09-26

    Consorzio RFX in Padova is currently using a comprehensive set of numerical and analytical codes, for the physics and engineering design of the SPIDER (Source for Production of Ion of Deuterium Extracted from RF plasma) and MITICA (Megavolt ITER Injector Concept Advancement) experiments, planned to be built at Consorzio RFX. This paper presents a set of studies on different possible geometries for the MITICA accelerator, with the objective to compare different design concepts and choose the most suitable one (or ones) to be further developed and possibly adopted in the experiment. Different design solutions have been discussed and compared, taking into account their advantages and drawbacks by both the physics and engineering points of view.

  15. Physics and engineering studies on the MITICA accelerator: comparison among possible design solutions

    NASA Astrophysics Data System (ADS)

    Agostinetti, P.; Antoni, V.; Cavenago, M.; Chitarin, G.; Pilan, N.; Marcuzzi, D.; Serianni, G.; Veltri, P.

    2011-09-01

    Consorzio RFX in Padova is currently using a comprehensive set of numerical and analytical codes, for the physics and engineering design of the SPIDER (Source for Production of Ion of Deuterium Extracted from RF plasma) and MITICA (Megavolt ITER Injector Concept Advancement) experiments, planned to be built at Consorzio RFX. This paper presents a set of studies on different possible geometries for the MITICA accelerator, with the objective to compare different design concepts and choose the most suitable one (or ones) to be further developed and possibly adopted in the experiment. Different design solutions have been discussed and compared, taking into account their advantages and drawbacks by both the physics and engineering points of view.

  16. GOTHIC: Gravitational oct-tree code accelerated by hierarchical time step controlling

    NASA Astrophysics Data System (ADS)

    Miki, Yohei; Umemura, Masayuki

    2017-04-01

    The tree method is a widely implemented algorithm for collisionless N-body simulations in astrophysics well suited for GPU(s). Adopting hierarchical time stepping can accelerate N-body simulations; however, it is infrequently implemented and its potential remains untested in GPU implementations. We have developed a Gravitational Oct-Tree code accelerated by HIerarchical time step Controlling named GOTHIC, which adopts both the tree method and the hierarchical time step. The code adopts some adaptive optimizations by monitoring the execution time of each function on-the-fly and minimizes the time-to-solution by balancing the measured time of multiple functions. Results of performance measurements with realistic particle distribution performed on NVIDIA Tesla M2090, K20X, and GeForce GTX TITAN X, which are representative GPUs of the Fermi, Kepler, and Maxwell generation of GPUs, show that the hierarchical time step achieves a speedup by a factor of around 3-5 times compared to the shared time step. The measured elapsed time per step of GOTHIC is 0.30 s or 0.44 s on GTX TITAN X when the particle distribution represents the Andromeda galaxy or the NFW sphere, respectively, with 224 = 16,777,216 particles. The averaged performance of the code corresponds to 10-30% of the theoretical single precision peak performance of the GPU.

  17. Data Evaluation Acquired Talys 1.0 Code to Produce 111In from Various Accelerator-Based Reactions

    NASA Astrophysics Data System (ADS)

    Alipoor, Zahra; Gholamzadeh, Zohreh; Sadeghi, Mahdi; Seyyedi, Solaleh; Aref, Morteza

    The Indium-111 physical-decay parameters as a β-emitter radionuclide show some potential for radiodiagnostic and radiotherapeutic purposes. Medical investigators have shown that 111In is an important radionuclide for locating and imaging certain tumors, visualization of the lymphatic system and thousands of labeling reactions have been suggested. The TALYS 1.0 code was used here to calculate excitation functions of 112/114-118Sn+p, 110Cd+3He, 109Ag+3He, 111-114Cd+p, 110/111Cd+d, 109Ag+α to produce 111In using low and medium energy accelerators. Calculations were performed up to 200 MeV. Appropriate target thicknesses have been assumed based on energy loss calculations with the SRIM code. Theoretical integral yields for all the latter reactions were calculated. The TALYS 1.0 code predicts that the production of a few curies of 111In is feasible using a target of isotopically highly enriched 112Cd and a proton energy between 12 and 25 MeV with a production rate as 248.97 MBq·μA-1 · h-1. Minimum impurities shall be produced during the proton irradiation of an enriched 111Cd target yielding a production rate for 111In of 67.52 MBq· μA-1 · h-1.

  18. Lattice physics capabilities of the SCALE code system using TRITON

    SciTech Connect

    DeHart, M. D.

    2006-07-01

    This paper describes ongoing calculations used to validate the TRITON depletion module in SCALE for light water reactor (LWR) fuel lattices. TRITON has been developed to provide improved resolution for lattice physics mixed-oxide fuel assemblies as programs to burn such fuel in the United States begin to come online. Results are provided for coupled TRITON/PARCS analyses of an LWR core in which TRITON was employed for generation of appropriately weighted few-group nodal cross-sectional sets for use in core-level calculations using PARCS. Additional results are provided for code-to-code comparisons for TRITON and a suite of other depletion packages in the modeling of a conceptual next-generation boiling water reactor fuel assembly design. Results indicate that the set of SCALE functional modules used within TRITON provide an accurate means for lattice physics calculations. Because the transport solution within TRITON provides a generalized-geometry capability, this capability is extensible to a wide variety of non-traditional and advanced fuel assembly designs. (authors)

  19. ASP2012: Fundamental Physics and Accelerator Sciences in Africa

    NASA Astrophysics Data System (ADS)

    Darve, Christine

    2012-02-01

    Much remains to be done to improve education and scientific research in Africa. Supported by the international scientific community, our initiative has been to contribute to fostering science in sub-Saharan Africa by establishing a biennial school on fundamental subatomic physics and its applications. The school is based on a close interplay between theoretical, experimental, and applied physics. The lectures are addressed to students or young researchers with at least a background of 4 years of university formation. The aim of the school is to develop capacity, interpret, and capitalize on the results of current and future physics experiments with particle accelerators; thereby spreading education for innovation in related applications and technologies, such as medicine and information science. Following the worldwide success of the first school edition, which gathered 65 students for 3-week in Stellenbosch (South Africa) in August 2010, the second edition will be hosted in Ghana from July 15 to August 4, 2012. The school is a non-profit organization, which provides partial or full financial support to 50 of the selected students, with priority to Sub-Saharan African students.

  20. Progress on accelerated calculation of 3D MHD equilibrium with the PIES code

    NASA Astrophysics Data System (ADS)

    Raburn, Daniel; Reiman, Allan; Monticello, Donald

    2016-10-01

    Continuing progress has been made in accelerating the 3D MHD equilibrium code, PIES, using an external numerical wrapper. The PIES code (Princeton Iterative Equilibrium Solver) is capable of calculating 3D MHD equilibria with islands. The numerical wrapper has been demonstrated to greatly improve the rate of convergence in numerous cases corresponding to equilibria in the TFTR device where magnetic islands are present; the numerical wrapper makes use of a Jacobian-free Newton-Krylov solver along with adaptive preconditioning and a sophisticated subspace-restricted Levenberg backtracking algorithm. The wrapper has recently been improved by automation which combines the preexisting backtracking algorithm with insights gained from the stability of the Picard algorithm traditionally used with PIES. Improved progress logging and stopping criteria have also been incorporated in to the numerical wrapper.

  1. Long-range accelerated BOTDA sensor using adaptive linear prediction and cyclic coding.

    PubMed

    Muanenda, Yonas; Taki, Mohammad; Pasquale, Fabrizio Di

    2014-09-15

    We propose and experimentally demonstrate a long-range accelerated Brillouin optical time domain analysis (BOTDA) sensor that exploits the complementary noise reduction benefits of adaptive linear prediction and optical pulse coding. The combined technique allows using orders of magnitude less the number of averages of the backscattered BOTDA traces compared to a standard single pulse BOTDA, enabling distributed strain measurement over 10 km of a standard single mode fiber with meter-scale spatial resolution and 1.8 MHz Brillouin frequency shift resolution. By optimizing the system parameters, the measurement is achieved with only 20 averages for each Brillouin gain spectrum scanned frequency, allowing for an eight times faster strain measurement compared to the use of cyclic pulse coding alone.

  2. The Scanning Electron Microscope As An Accelerator For The Undergraduate Advanced Physics Laboratory

    SciTech Connect

    Peterson, Randolph S.; Berggren, Karl K.; Mondol, Mark

    2011-06-01

    Few universities or colleges have an accelerator for use with advanced physics laboratories, but many of these institutions have a scanning electron microscope (SEM) on site, often in the biology department. As an accelerator for the undergraduate, advanced physics laboratory, the SEM is an excellent substitute for an ion accelerator. Although there are no nuclear physics experiments that can be performed with a typical 30 kV SEM, there is an opportunity for experimental work on accelerator physics, atomic physics, electron-solid interactions, and the basics of modern e-beam lithography.

  3. Health Physics Code System for Evaluating Accidents Involving Radioactive Materials.

    SciTech Connect

    2014-10-01

    Version 03 The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculational tool for evaluating accidents involving radioactive materials. HOTSPOT codes provide a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. The developer's website is: http://www.llnl.gov/nhi/hotspot/. Four general programs, PLUME, EXPLOSION, FIRE, and RESUSPENSION, calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Additional programs deal specifically with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons. The FIDLER program can calibrate radiation survey instruments for ground survey measurements and initial screening of personnel for possible plutonium uptake in the lung. The HOTSPOT codes are fast, portable, easy to use, and fully documented in electronic help files. HOTSPOT supports color high resolution monitors and printers for concentration plots and contours. The codes have been extensively used by the DOS community since 1985. Tables and graphical output can be directed to the computer screen, printer, or a disk file. The graphical output consists of dose and ground contamination as a function of plume centerline downwind distance, and radiation dose and ground contamination contours. Users have the option of displaying scenario text on the plots. HOTSPOT 3.0.1 fixes three significant Windows 7 issues: � Executable installed properly under "Program Files/HotSpot 3.0". Installation package now smaller: removed dependency on older Windows DLL files which previously needed to \\ � Forms now properly scale based on DPI instead of font for users who change their screen resolution to something other than 100%. This is a more common feature in Windows 7.

  4. Acceleration of a Particle-in-Cell Code for Space Plasma Simulations with OpenACC

    NASA Astrophysics Data System (ADS)

    Peng, Ivy Bo; Markidis, Stefano; Vaivads, Andris; Vencels, Juris; Deca, Jan; Lapenta, Giovanni; Hart, Alistair; Laure, Erwin

    2015-04-01

    We simulate space plasmas with the Particle-in-cell (PIC) method that uses computational particles to mimic electrons and protons in solar wind and in Earth magnetosphere. The magnetic and electric fields are computed by solving the Maxwell's equations on a computational grid. In each PIC simulation step, there are four major phases: interpolation of fields to particles, updating the location and velocity of each particle, interpolation of particles to grids and solving the Maxwell's equations on the grid. We use the iPIC3D code, which was implemented in C++, using both MPI and OpenMP, for our case study. By November 2014, heterogeneous systems using hardware accelerators such as Graphics Processing Unit (GPUs) and the Many Integrated Core (MIC) coprocessors for high performance computing continue growth in the top 500 most powerful supercomputers world wide. Scientific applications for numerical simulations need to adapt to using accelerators to achieve portability and scalability in the coming exascale systems. In our work, we conduct a case study of using OpenACC to offload the computation intensive parts: particle mover and interpolation of particles to grids, in a massively parallel Particle-in-Cell simulation code, iPIC3D, to multi-GPU systems. We use MPI for inter-node communication for halo exchange and communicating particles. We identify the most promising parts suitable for GPUs accelerator by profiling using CrayPAT. We implemented manual deep copy to address the challenges of porting C++ classes to GPU. We document the necessary changes in the exiting algorithms to adapt for GPU computation. We present the challenges and findings as well as our methodology for porting a Particle-in-Cell code to multi-GPU systems using OpenACC. In this work, we will present the challenges, findings and our methodology of porting a Particle-in-Cell code for space applications as follows: We profile the iPIC3D code by Cray Performance Analysis Tool (CrayPAT) and identify

  5. A GPU accelerated Barnes-Hut tree code for FLASH4

    NASA Astrophysics Data System (ADS)

    Lukat, Gunther; Banerjee, Robi

    2016-05-01

    We present a GPU accelerated CUDA-C implementation of the Barnes Hut (BH) tree code for calculating the gravitational potential on octree adaptive meshes. The tree code algorithm is implemented within the FLASH4 adaptive mesh refinement (AMR) code framework and therefore fully MPI parallel. We describe the algorithm and present test results that demonstrate its accuracy and performance in comparison to the algorithms available in the current FLASH4 version. We use a MacLaurin spheroid to test the accuracy of our new implementation and use spherical, collapsing cloud cores with effective AMR to carry out performance tests also in comparison with previous gravity solvers. Depending on the setup and the GPU/CPU ratio, we find a speedup for the gravity unit of at least a factor of 3 and up to 60 in comparison to the gravity solvers implemented in the FLASH4 code. We find an overall speedup factor for full simulations of at least factor 1.6 up to a factor of 10.

  6. Topics in radiation at accelerators: Radiation physics for personnel and environmental protection

    SciTech Connect

    Cossairt, J.D.

    1996-10-01

    In the first chapter, terminology, physical and radiological quantities, and units of measurement used to describe the properties of accelerator radiation fields are reviewed. The general considerations of primary radiation fields pertinent to accelerators are discussed. The primary radiation fields produced by electron beams are described qualitatively and quantitatively. In the same manner the primary radiation fields produced by proton and ion beams are described. Subsequent chapters describe: shielding of electrons and photons at accelerators; shielding of proton and ion accelerators; low energy prompt radiation phenomena; induced radioactivity at accelerators; topics in radiation protection instrumentation at accelerators; and accelerator radiation protection program elements.

  7. GeNN: a code generation framework for accelerated brain simulations

    NASA Astrophysics Data System (ADS)

    Yavuz, Esin; Turner, James; Nowotny, Thomas

    2016-01-01

    Large-scale numerical simulations of detailed brain circuit models are important for identifying hypotheses on brain functions and testing their consistency and plausibility. An ongoing challenge for simulating realistic models is, however, computational speed. In this paper, we present the GeNN (GPU-enhanced Neuronal Networks) framework, which aims to facilitate the use of graphics accelerators for computational models of large-scale neuronal networks to address this challenge. GeNN is an open source library that generates code to accelerate the execution of network simulations on NVIDIA GPUs, through a flexible and extensible interface, which does not require in-depth technical knowledge from the users. We present performance benchmarks showing that 200-fold speedup compared to a single core of a CPU can be achieved for a network of one million conductance based Hodgkin-Huxley neurons but that for other models the speedup can differ. GeNN is available for Linux, Mac OS X and Windows platforms. The source code, user manual, tutorials, Wiki, in-depth example projects and all other related information can be found on the project website http://genn-team.github.io/genn/.

  8. Status of MAPA (Modular Accelerator Physics Analysis) and the Tech-X Object-Oriented Accelerator Library

    NASA Astrophysics Data System (ADS)

    Cary, J. R.; Shasharina, S.; Bruhwiler, D. L.

    1998-04-01

    The MAPA code is a fully interactive accelerator modeling and design tool consisting of a GUI and two object-oriented C++ libraries: a general library suitable for treatment of any dynamical system, and an accelerator library including many element types plus an accelerator class. The accelerator library inherits directly from the system library, which uses hash tables to store any relevant parameters or strings. The GUI can access these hash tables in a general way, allowing the user to invoke a window displaying all relevant parameters for a particular element type or for the accelerator class, with the option to change those parameters. The system library can advance an arbitrary number of dynamical variables through an arbitrary mapping. The accelerator class inherits this capability and overloads the relevant functions to advance the phase space variables of a charged particle through a string of elements. Among other things, the GUI makes phase space plots and finds fixed points of the map. We discuss the object hierarchy of the two libraries and use of the code.

  9. Novel methods in the Particle-In-Cell accelerator Code-Framework Warp

    SciTech Connect

    Vay, J-L; Grote, D. P.; Cohen, R. H.; Friedman, A.

    2012-12-26

    The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high-energy density experiments and implosion of inertial fusion capsules. It is also applied in various areas outside the Heavy Ion Fusion program to the study and design of existing and next-generation high-energy accelerators, including the study of electron cloud effects and laser wakefield acceleration for example. This study presents an overview of Warp's capabilities, summarizing recent original numerical methods that were developed by the HIFS-VNL (including PIC with adaptive mesh refinement, a large-timestep 'drift-Lorentz' mover for arbitrarily magnetized species, a relativistic Lorentz invariant leapfrog particle pusher, simulations in Lorentz-boosted frames, an electromagnetic solver with tunable numerical dispersion and efficient stride-based digital filtering), with special emphasis on the description of the mesh refinement capability. In addition, selected examples of the applications of the methods to the abovementioned fields are given.

  10. Physics under the bonnet of a stellar evolution code

    NASA Astrophysics Data System (ADS)

    Stancliffe, Richard J.

    Just how good are modern stellar models? Providing a rigorous assessment of the uncertainties is difficult because of the multiplicity of input physics. Some of the ingredients are reasonably well-known (like reaction rates and opacities). Others are not so good, with convection standing out as a particularly obvious example. In some cases, it is not clear what the ingredients should be: what role do atomic diffusion, rotation, magnetic fields, etc. play in stellar evolution? All this is then compounded by computational method. In converting all this physics into something we can implement in a 1D evolution code, we are forced to make choices about the way the equations are solved, how we will treat mixing at convective boundaries, etc. All of this can impact the models one finally generates. In this review, I will attempt to assess the uncertainties associated with the ingredients and methods used by stellar evolution modellers, and what their impacts may be on the science that we wish to do.

  11. Accelerating Convolutional Sparse Coding for Curvilinear Structures Segmentation by Refining SCIRD-TS Filter Banks.

    PubMed

    Annunziata, Roberto; Trucco, Emanuele

    2016-11-01

    Deep learning has shown great potential for curvilinear structure (e.g., retinal blood vessels and neurites) segmentation as demonstrated by a recent auto-context regression architecture based on filter banks learned by convolutional sparse coding. However, learning such filter banks is very time-consuming, thus limiting the amount of filters employed and the adaptation to other data sets (i.e., slow re-training). We address this limitation by proposing a novel acceleration strategy to speed-up convolutional sparse coding filter learning for curvilinear structure segmentation. Our approach is based on a novel initialisation strategy (warm start), and therefore it is different from recent methods improving the optimisation itself. Our warm-start strategy is based on carefully designed hand-crafted filters (SCIRD-TS), modelling appearance properties of curvilinear structures which are then refined by convolutional sparse coding. Experiments on four diverse data sets, including retinal blood vessels and neurites, suggest that the proposed method reduces significantly the time taken to learn convolutional filter banks (i.e., up to -82%) compared to conventional initialisation strategies. Remarkably, this speed-up does not worsen performance; in fact, filters learned with the proposed strategy often achieve a much lower reconstruction error and match or exceed the segmentation performance of random and DCT-based initialisation, when used as input to a random forest classifier.

  12. Acceleration of the Geostatistical Software Library (GSLIB) by code optimization and hybrid parallel programming

    NASA Astrophysics Data System (ADS)

    Peredo, Oscar; Ortiz, Julián M.; Herrero, José R.

    2015-12-01

    The Geostatistical Software Library (GSLIB) has been used in the geostatistical community for more than thirty years. It was designed as a bundle of sequential Fortran codes, and today it is still in use by many practitioners and researchers. Despite its widespread use, few attempts have been reported in order to bring this package to the multi-core era. Using all CPU resources, GSLIB algorithms can handle large datasets and grids, where tasks are compute- and memory-intensive applications. In this work, a methodology is presented to accelerate GSLIB applications using code optimization and hybrid parallel processing, specifically for compute-intensive applications. Minimal code modifications are added decreasing as much as possible the elapsed time of execution of the studied routines. If multi-core processing is available, the user can activate OpenMP directives to speed up the execution using all resources of the CPU. If multi-node processing is available, the execution is enhanced using MPI messages between the compute nodes.Four case studies are presented: experimental variogram calculation, kriging estimation, sequential gaussian and indicator simulation. For each application, three scenarios (small, large and extra large) are tested using a desktop environment with 4 CPU-cores and a multi-node server with 128 CPU-nodes. Elapsed times, speedup and efficiency results are shown.

  13. Physics and numerics of the tensor code (incomplete preliminary documentation)

    SciTech Connect

    Burton, D.E.; Lettis, L.A. Jr.; Bryan, J.B.; Frary, N.R.

    1982-07-15

    The present TENSOR code is a descendant of a code originally conceived by Maenchen and Sack and later adapted by Cherry. Originally, the code was a two-dimensional Lagrangian explicit finite difference code which solved the equations of continuum mechanics. Since then, implicit and arbitrary Lagrange-Euler (ALE) algorithms have been added. The code has been used principally to solve problems involving the propagation of stress waves through earth materials, and considerable development of rock and soil constitutive relations has been done. The code has been applied extensively to the containment of underground nuclear tests, nuclear and high explosive surface and subsurface cratering, and energy and resource recovery. TENSOR is supported by a substantial array of ancillary routines. The initial conditions are set up by a generator code TENGEN. ZON is a multipurpose code which can be used for zoning, rezoning, overlaying, and linking from other codes. Linking from some codes is facilitated by another code RADTEN. TENPLT is a fixed time graphics code which provides a wide variety of plotting options and output devices, and which is capable of producing computer movies by postprocessing problem dumps. Time history graphics are provided by the TIMPLT code from temporal dumps produced during production runs. While TENSOR can be run as a stand-alone controllee, a special controller code TCON is available to better interface the code with the LLNL computer system during production jobs. In order to standardize compilation procedures and provide quality control, a special compiler code BC is used. A number of equation of state generators are available among them ROC and PMUGEN.

  14. LCODE: A parallel quasistatic code for computationally heavy problems of plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Sosedkin, A. P.; Lotov, K. V.

    2016-09-01

    LCODE is a freely distributed quasistatic 2D3V code for simulating plasma wakefield acceleration, mainly specialized at resource-efficient studies of long-term propagation of ultrarelativistic particle beams in plasmas. The beam is modeled with fully relativistic macro-particles in a simulation window copropagating with the light velocity; the plasma can be simulated with either kinetic or fluid model. Several techniques are used to obtain exceptional numerical stability and precision while maintaining high resource efficiency, enabling LCODE to simulate the evolution of long particle beams over long propagation distances even on a laptop. A recent upgrade enabled LCODE to perform the calculations in parallel. A pipeline of several LCODE processes communicating via MPI (Message-Passing Interface) is capable of executing multiple consecutive time steps of the simulation in a single pass. This approach can speed up the calculations by hundreds of times.

  15. 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

  16. Physics models in the toroidal transport code PROCTR

    SciTech Connect

    Howe, H.C.

    1990-08-01

    The physics models that are contained in the toroidal transport code PROCTR are described in detail. Time- and space-dependent models are included for the plasma hydrogenic-ion, helium, and impurity densities, the electron and ion temperatures, the toroidal rotation velocity, and the toroidal current profile. Time- and depth-dependent models for the trapped and mobile hydrogenic particle concentrations in the wall and a time-dependent point model for the number of particles in the limiter are also included. Time-dependent models for neutral particle transport, neutral beam deposition and thermalization, fusion heating, impurity radiation, pellet injection, and the radial electric potential are included and recalculated periodically as the time-dependent models evolve. The plasma solution is obtained either in simple flux coordinates, where the radial shift of each elliptical, toroidal flux surface is included to maintain an approximate pressure equilibrium, or in general three-dimensional torsatron coordinates represented by series of helical harmonics. The detailed coupling of the plasma, scrape-off layer, limiter, and wall models through the neutral transport model makes PROCTR especially suited for modeling of recycling and particle control in toroidal plasmas. The model may also be used in a steady-state profile analysis mode for studying energy and particle balances starting with measured plasma profiles.

  17. 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.

  18. Genetic algorithms and their applications in accelerator physics

    SciTech Connect

    Hofler, Alicia S.

    2013-12-01

    Multi-objective optimization techniques are widely used in an extremely broad range of fields. Genetic optimization for multi-objective optimization was introduced in the accelerator community in relatively recent times and quickly spread becoming a fundamental tool in multi-dimensional optimization problems. This discussion introduces the basics of the technique and reviews applications in accelerator problems.

  19. Accelerator mass spectrometry: from nuclear physics to dating

    SciTech Connect

    Kutschera, W.

    1983-01-01

    Several applications of accelerator-based mass spectroscopy are reviewed. Among these are the search for unknown species, determination of comogenic radioisotopes in natural materials and measurements of half-lifes, especially those of significance to dating. Accelerator parameters and techniques of importance for these applications are also considered.

  20. "SMART": A Compact and Handy FORTRAN Code for the Physics of Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Sapar, A.; Poolamäe, R.

    2003-01-01

    A new computer code SMART (Spectra from Model Atmospheres by Radiative Transfer) for computing the stellar spectra, forming in plane-parallel atmospheres, has been compiled by us and A. Aret. To guarantee wide compatibility of the code with shell environment, we chose FORTRAN-77 as programming language and tried to confine ourselves to common part of its numerous versions both in WINDOWS and LINUX. SMART can be used for studies of several processes in stellar atmospheres. The current version of the programme is undergoing rapid changes due to our goal to elaborate a simple, handy and compact code. Instead of linearisation (being a mathematical method of recurrent approximations) we propose to use the physical evolutionary changes or in other words relaxation of quantum state populations rates from LTE to NLTE has been studied using small number of NLTE states. This computational scheme is essentially simpler and more compact than the linearisation. This relaxation scheme enables using instead of the Λ-iteration procedure a physically changing emissivity (or the source function) which incorporates in itself changing Menzel coefficients for NLTE quantum state populations. However, the light scattering on free electrons is in the terms of Feynman graphs a real second-order quantum process and cannot be reduced to consequent processes of absorption and emission as in the case of radiative transfer in spectral lines. With duly chosen input parameters the code SMART enables computing radiative acceleration to the matter of stellar atmosphere in turbulence clumps. This also enables to connect the model atmosphere in more detail with the problem of the stellar wind triggering. Another problem, which has been incorporated into the computer code SMART, is diffusion of chemical elements and their isotopes in the atmospheres of chemically peculiar (CP) stars due to usual radiative acceleration and the essential additional acceleration generated by the light-induced drift. As

  1. TEACHING PHYSICS: Atwood's machine: experiments in an accelerating frame

    NASA Astrophysics Data System (ADS)

    Teck Chee, Chia; Hong, Chia Yee

    1999-03-01

    Experiments in an accelerating frame are often difficult to perform, but simple computer software allows sufficiently rapid and accurate measurements to be made on an arrangement of weights and pulleys known as Atwood's machine.

  2. Medical physics--particle accelerators--the beginning.

    PubMed

    Ganz, Jeremy C

    2014-01-01

    This chapter outlines the early development of particle accelerators with the redesign from linear accelerator to cyclotron by Ernest Lawrence with a view to reducing the size of the machines as the power increased. There are minibiographies of Ernest Lawrence and his brother John. The concept of artificial radiation is outlined and the early attempts at patient treatment are mentioned. The reasons for trying and abandoning neutron therapy are discussed, and the early use of protons is described.

  3. Evaluation of ‘OpenCL for FPGA’ for Data Acquisition and Acceleration in High Energy Physics

    NASA Astrophysics Data System (ADS)

    Sridharan, Srikanth

    2015-12-01

    The increase in the data acquisition and processing needs of High Energy Physics experiments has made it more essential to use FPGAs to meet those needs. However harnessing the capabilities of the FPGAs has been hard for anyone but expert FPGA developers. The arrival of OpenCL with the two major FPGA vendors supporting it, offers an easy software-based approach to taking advantage of FPGAs in applications such as High Energy Physics. OpenCL is a language for using heterogeneous architectures in order to accelerate applications. However, FPGAs are capable of far more than acceleration, hence it is interesting to explore if OpenCL can be used to take advantage of FPGAs for more generic applications. To answer these questions, especially in the context of High Energy Physics, two applications, a DAQ module and an acceleration workload, were tested for implementation with OpenCL on FPGAs2. The challenges on using OpenCL for a DAQ application and their solutions, together with the performance of the OpenCL based acceleration are discussed. Many of the design elements needed to realize a DAQ system in OpenCL already exists, mostly as FPGA vendor extensions, but a small number of elements were found to be missing. For acceleration of OpenCL applications, using FPGAs has become as easy as using GPUs. OpenCL has the potential for a massive gain in productivity and ease of use enabling non FPGA experts to design, debug and maintain the code. Also, FPGA power consumption is much lower than other implementations. This paper describes one of the first attempts to explore the use of OpenCL for applications outside the acceleration workloads.

  4. 29 CFR 1910.144 - Safety color code for marking physical hazards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Safety color code for marking physical hazards. 1910.144... § 1910.144 Safety color code for marking physical hazards. (a) Color identification—(1) Red. Red shall be the basic color for the identification of: (i) Fire protection equipment and apparatus. (ii)...

  5. 29 CFR 1915.90 - Safety color code for marking physical hazards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Safety color code for marking physical hazards. 1915.90 Section 1915.90 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... General Working Conditions § 1915.90 Safety color code for marking physical hazards. The...

  6. 29 CFR 1910.144 - Safety color code for marking physical hazards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Safety color code for marking physical hazards. 1910.144 Section 1910.144 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... § 1910.144 Safety color code for marking physical hazards. (a) Color identification—(1) Red. Red shall...

  7. 29 CFR 1910.144 - Safety color code for marking physical hazards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Safety color code for marking physical hazards. 1910.144... § 1910.144 Safety color code for marking physical hazards. (a) Color identification—(1) Red. Red shall be the basic color for the identification of: (i) Fire protection equipment and apparatus. (ii)...

  8. Assessment of the prevailing physics codes: LEOPARD, LASER, and EPRI-CELL

    SciTech Connect

    Lan, J.S.

    1981-01-01

    In order to analyze core performance and fuel management, it is necessary to verify reactor physics codes in great detail. This kind of work not only serves the purpose of understanding and controlling the characteristics of each code, but also ensures the reliability as codes continually change due to constant modifications and machine transfers. This paper will present the results of a comprehensive verification of three code packages - LEOPARD, LASER, and EPRI-CELL.

  9. Formation and Acceleration Physics on Plasma Injector 1

    NASA Astrophysics Data System (ADS)

    Howard, Stephen

    2012-10-01

    Plasma Injector 1 (PI-1) is a two stage coaxial Marshal gun with conical accelerator electrodes, similar in shape to the MARAUDER device, with power input of the same topology as the RACE device. The goal of PI-1 research is to produce a self-confined compact toroid with high-flux (200 mWb), high-density (3x10^16 cm-3) and moderate initial temperature (100 eV) to be used as the target plasma in a MTF reactor. PI-1 is 5 meters long and 1.9 m in diameter at the expansion region where a high aspect ratio (4.4) spheromak is formed with a minimum lambda of 9 m-1. The acceleration stage is 4 m long and tapers to an outer diameter of 40 cm. The capacitor banks store 0.5 MJ for formation and 1.13 MJ for acceleration. Power is delivered via 62 independently controlled switch modules. Several geometries for formation bias field, inner electrodes and target chamber have been tested, and trends in accelerator efficiency and target lifetime have been observed. Thomson scattering and ion Doppler spectroscopy show significant heating (>100 eV) as the CT is compressed in the conical accelerator. B-dot probes show magnetic field structure consistent with Grad-Shafranov models and MHD simulations, and CT axial length depends strongly on the lambda profile.

  10. A theory manual for multi-physics code coupling in LIME.

    SciTech Connect

    Belcourt, Noel; Bartlett, Roscoe Ainsworth; Pawlowski, Roger Patrick; Schmidt, Rodney Cannon; Hooper, Russell Warren

    2011-03-01

    The Lightweight Integrating Multi-physics Environment (LIME) is a software package for creating multi-physics simulation codes. Its primary application space is when computer codes are currently available to solve different parts of a multi-physics problem and now need to be coupled with other such codes. In this report we define a common domain language for discussing multi-physics coupling and describe the basic theory associated with multiphysics coupling algorithms that are to be supported in LIME. We provide an assessment of coupling techniques for both steady-state and time dependent coupled systems. Example couplings are also demonstrated.

  11. High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    SciTech Connect

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-07-28

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable of handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.

  12. High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    DOE PAGES

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-07-28

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable ofmore » handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.« less

  13. Accelerator System Model (ASM) user manual with physics and engineering model documentation. ASM version 1.0

    SciTech Connect

    1993-07-01

    The Accelerator System Model (ASM) is a computer program developed to model proton radiofrequency accelerators and to carry out system level trade studies. The ASM FORTRAN subroutines are incorporated into an intuitive graphical user interface which provides for the {open_quotes}construction{close_quotes} of the accelerator in a window on the computer screen. The interface is based on the Shell for Particle Accelerator Related Codes (SPARC) software technology written for the Macintosh operating system in the C programming language. This User Manual describes the operation and use of the ASM application within the SPARC interface. The Appendix provides a detailed description of the physics and engineering models used in ASM. ASM Version 1.0 is joint project of G. H. Gillespie Associates, Inc. and the Accelerator Technology (AT) Division of the Los Alamos National Laboratory. Neither the ASM Version 1.0 software nor this ASM Documentation may be reproduced without the expressed written consent of both the Los Alamos National Laboratory and G. H. Gillespie Associates, Inc.

  14. The GENGA code: gravitational encounters in N-body simulations with GPU acceleration

    SciTech Connect

    Grimm, Simon L.; Stadel, Joachim G.

    2014-11-20

    We describe an open source GPU implementation of a hybrid symplectic N-body integrator, GENGA (Gravitational ENcounters with Gpu Acceleration), designed to integrate planet and planetesimal dynamics in the late stage of planet formation and stability analyses of planetary systems. GENGA uses a hybrid symplectic integrator to handle close encounters with very good energy conservation, which is essential in long-term planetary system integration. We extended the second-order hybrid integration scheme to higher orders. The GENGA code supports three simulation modes: integration of up to 2048 massive bodies, integration with up to a million test particles, or parallel integration of a large number of individual planetary systems. We compare the results of GENGA to Mercury and pkdgrav2 in terms of energy conservation and performance and find that the energy conservation of GENGA is comparable to Mercury and around two orders of magnitude better than pkdgrav2. GENGA runs up to 30 times faster than Mercury and up to 8 times faster than pkdgrav2. GENGA is written in CUDA C and runs on all NVIDIA GPUs with a computing capability of at least 2.0.

  15. A portable platform for accelerated PIC codes and its application to GPUs using OpenACC

    NASA Astrophysics Data System (ADS)

    Hariri, F.; Tran, T. M.; Jocksch, A.; Lanti, E.; Progsch, J.; Messmer, P.; Brunner, S.; Gheller, C.; Villard, L.

    2016-10-01

    We present a portable platform, called PIC_ENGINE, for accelerating Particle-In-Cell (PIC) codes on heterogeneous many-core architectures such as Graphic Processing Units (GPUs). The aim of this development is efficient simulations on future exascale systems by allowing different parallelization strategies depending on the application problem and the specific architecture. To this end, this platform contains the basic steps of the PIC algorithm and has been designed as a test bed for different algorithmic options and data structures. Among the architectures that this engine can explore, particular attention is given here to systems equipped with GPUs. The study demonstrates that our portable PIC implementation based on the OpenACC programming model can achieve performance closely matching theoretical predictions. Using the Cray XC30 system, Piz Daint, at the Swiss National Supercomputing Centre (CSCS), we show that PIC_ENGINE running on an NVIDIA Kepler K20X GPU can outperform the one on an Intel Sandy bridge 8-core CPU by a factor of 3.4.

  16. International Linear Collider Accelerator Physics R&D

    SciTech Connect

    George D. Gollin; Michael Davidsaver; Michael J. Haney; Michael Kasten; Jason Chang; Perry Chodash; Will Dluger; Alex Lang; Yehan Liu

    2008-09-03

    ILC work at Illinois has concentrated primarily on technical issues relating to the design of the accelerator. Because many of the problems to be resolved require a working knowledge of classical mechanics and electrodynamics, most of our research projects lend themselves well to the participation of undergraduate research assistants. The undergraduates in the group are scientists, not technicians, and find solutions to problems that, for example, have stumped PhD-level staff elsewhere. The ILC Reference Design Report calls for 6.7 km circumference damping rings (which prepare the beams for focusing) using “conventional” stripline kickers driven by fast HV pulsers. Our primary goal was to determine the suitability of the 16 MeV electron beam in the AØ region at Fermilab for precision kicker studies.We found that the low beam energy and lack of redundancy in the beam position monitor system complicated the analysis of our data. In spite of these issues we concluded that the precision we could obtain was adequate to measure the performance and stability of a production module of an ILC kicker, namely 0.5%. We concluded that the kicker was stable to an accuracy of ~2.0% and that we could measure this precision to an accuracy of ~0.5%. As a result, a low energy beam like that at AØ could be used as a rapid-turnaround facility for testing ILC production kicker modules. The ILC timing precision for arrival of bunches at the collision point is required to be 0.1 picosecond or better. We studied the bunch-to-bunch timing accuracy of a “phase detector” installed in AØ in order to determine its suitability as an ILC bunch timing device. A phase detector is an RF structure excited by the passage of a bunch. Its signal is fed through a 1240 MHz high-Q resonant circuit and then down-mixed with the AØ 1300 MHz accelerator RF. We used a kind of autocorrelation technique to compare the phase detector signal with a reference signal obtained from the phase detector

  17. Acceleration of neutrons in a scheme of a tautochronous mathematical pendulum (physical principles)

    SciTech Connect

    Rivlin, Lev A

    2010-12-09

    We consider the physical principles of neutron acceleration through a multiple synchronous interaction with a gradient rf magnetic field in a scheme of a tautochronous mathematical pendulum. (laser applications and other aspects of quantum electronics)

  18. Estimation of photoneutron yield in linear accelerator with different collimation systems by Geant4 and MCNPX simulation codes.

    PubMed

    Kim, Yoon Sang; Khazaei, Zeinab; Ko, Junho; Afarideh, Hossein; Ghergherehchi, Mitra

    2016-04-07

    At present, the bremsstrahlung photon beams produced by linear accelerators are the most commonly employed method of radiotherapy for tumor treatments. A photoneutron source based on three different energies (6, 10 and 15 MeV) of a linac electron beam was designed by means of Geant4 and Monte Carlo N-Particle eXtended (MCNPX) simulation codes. To obtain maximum neutron yield, two arrangements for the photo neutron convertor were studied: (a) without a collimator, and (b) placement of the convertor after the collimator. The maximum photon intensities in tungsten were 0.73, 1.24 and 2.07 photon/e at 6, 10 and 15 MeV, respectively. There was no considerable increase in the photon fluence spectra from 6 to 15 MeV at the optimum thickness between 0.8 mm and 2 mm of tungsten. The optimum dimensions of the collimator were determined to be a length of 140 mm with an aperture of 5 mm  ×  70 mm for iron in a slit shape. According to the neutron yield, the best thickness obtained for the studied materials was 30 mm. The number of neutrons generated in BeO achieved the maximum value at 6 MeV, unlike that in Be, where the highest number of neutrons was observed at 15 MeV. Statistical uncertainty in all simulations was less than 0.3% and 0.05% for MCNPX and the standard electromagnetic (EM) physics packages of Geant4, respectively. Differences among spectra in various regions are due to various cross-section and stopping power data and different simulations of the physics processes.

  19. Burnup calculations for KIPT accelerator driven subcritical facility using Monte Carlo computer codes-MCB and MCNPX.

    SciTech Connect

    Gohar, Y.; Zhong, Z.; Talamo, A.; Nuclear Engineering Division

    2009-06-09

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of an electron accelerator driven subcritical (ADS) facility, using the KIPT electron accelerator. The neutron source of the subcritical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The electron beam has a uniform spatial distribution and electron energy in the range of 100 to 200 MeV. The main functions of the subcritical assembly are the production of medical isotopes and the support of the Ukraine nuclear power industry. Neutron physics experiments and material structure analyses are planned using this facility. With the 100 KW electron beam power, the total thermal power of the facility is {approx}375 kW including the fission power of {approx}260 kW. The burnup of the fissile materials and the buildup of fission products reduce continuously the reactivity during the operation, which reduces the neutron flux level and consequently the facility performance. To preserve the neutron flux level during the operation, fuel assemblies should be added after long operating periods to compensate for the lost reactivity. This process requires accurate prediction of the fuel burnup, the decay behavior of the fission produces, and the introduced reactivity from adding fresh fuel assemblies. The recent developments of the Monte Carlo computer codes, the high speed capability of the computer processors, and the parallel computation techniques made it possible to perform three-dimensional detailed burnup simulations. A full detailed three-dimensional geometrical model is used for the burnup simulations with continuous energy nuclear data libraries for the transport calculations and 63-multigroup or one group cross sections libraries for the depletion calculations. Monte Carlo Computer code MCNPX and MCB are utilized for this study. MCNPX transports the

  20. Muon simulation codes MUSIC and MUSUN for underground physics

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, V. A.

    2009-03-01

    The paper describes two Monte Carlo codes dedicated to muon simulations: MUSIC (MUon SImulation Code) and MUSUN (MUon Simulations UNderground). MUSIC is a package for muon transport through matter. It is particularly useful for propagating muons through large thickness of rock or water, for instance from the surface down to underground/underwater laboratory. MUSUN is designed to use the results of muon transport through rock/water to generate muons in or around underground laboratory taking into account their energy spectrum and angular distribution.

  1. Seeing the Nature of the Accelerating Physics: It's a SNAP

    SciTech Connect

    Albert, J.; Aldering, G.; Allam, S.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Aumeunier, M.; Bailey, S.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstom, L.; Bernstein, G.; Bester, M.; Besuner, B.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; /Caltech /LBL, Berkeley /Fermilab /SLAC /Stockholm U. /Paris, IN2P3 /Marseille, CPPM /Marseille, Lab. Astrophys. /Yale U. /Pennsylvania U. /UC, Berkeley /Michigan U. /Baltimore, Space Telescope Sci. /Indiana U. /Caltech, JPL /Australian Natl. U., Canberra /American Astron. Society /Chicago U. /Cambridge U. /Saclay /Lyon, IPN

    2005-08-05

    For true insight into the nature of dark energy, measurements of the precision and accuracy of the Supernova/Acceleration Probe (SNAP) are required. Precursor or scaled-down experiments are unavoidably limited, even for distinguishing the cosmological constant. They can pave the way for, but should not delay, SNAP by developing calibration, refinement, and systematics control (and they will also provide important, exciting astrophysics).

  2. Physics of beam self-modulation in plasma wakefield accelerators

    SciTech Connect

    Lotov, K. V.

    2015-10-15

    The self-modulation instability is a key effect that makes possible the usage of nowadays proton beams as drivers for plasma wakefield acceleration. Development of the instability in uniform plasmas and in plasmas with a small density up-step is numerically studied with the focus at nonlinear stages of beam evolution. The step parameters providing the strongest established wakefield are found, and the mechanism of stable bunch train formation is identified.

  3. Accelerator Preparations for Muon Physics Experiments at Fermilab

    SciTech Connect

    Syphers, M.J.; /Fermilab

    2009-10-01

    The use of existing Fermilab facilities to provide beams for two muon experiments - the Muon to Electron Conversion Experiment (Mu2e) and the New g-2 Experiment - is under consideration. Plans are being pursued to perform these experiments following the completion of the Tevatron Collider Run II, utilizing the beam lines and storage rings used today for antiproton accumulation without considerable reconfiguration. Operating scenarios being investigated and anticipated accelerator improvements or reconfigurations will be presented.

  4. Field ionization model implemented in Particle In Cell code and applied to laser-accelerated carbon ions

    SciTech Connect

    Nuter, R.; Gremillet, L.; Lefebvre, E.; Levy, A.; Ceccotti, T.; Martin, P.

    2011-03-15

    A novel numerical modeling of field ionization in PIC (Particle In Cell) codes is presented. Based on the quasistatic approximation of the ADK (Ammosov Delone Krainov) theory and implemented through a Monte Carlo scheme, this model allows for multiple ionization processes. Two-dimensional PIC simulations are performed to analyze the cut-off energies of the laser-accelerated carbon ions measured on the UHI 10 Saclay facility. The influence of the target and the hydrocarbon pollutant composition on laser-accelerated carbon ion energies is demonstrated.

  5. Laser-based acceleration for nuclear physics experiments at ELI-NP

    NASA Astrophysics Data System (ADS)

    Tesileanu, O.; Asavei, Th.; Dancus, I.; Gales, S.; Negoita, F.; Turcu, I. C. E.; Ursescu, D.; Zamfir, N. V.

    2016-05-01

    As part of the Extreme Light pan-European research infrastructure, Extreme Light Infrastructure - Nuclear Physics (ELI-NP) in Romania will focus on topics in Nuclear Physics, fundamental Physics and applications, based on very intense photon beams. Laser-based acceleration of electrons, protons and heavy ions is a prerequisite for a multitude of laser-driven nuclear physics experiments already proposed by the international research community. A total of six outputs of the dual-amplification chain laser system, two of 100TW, two of 1PW and two of 10PW will be employed in 5 experimental areas, with the possibility to use long and short focal lengths, gas and solid targets, reaching the whole range of laser acceleration processes. We describe the main techniques and expectations regarding the acceleration of electrons, protons and heavy nuclei at ELI-NP, and some physics cases for which these techniques play an important role in the experiments.

  6. Physics at the Thomas Jefferson National Accelerator Facility

    SciTech Connect

    Lawrence Cardman

    2005-10-22

    The CEBAF accelerator at JLab is fulfilling its scientific mission to understand how hadrons are constructed from the quarks and gluons of QCD, to understand the QCD basis for the nucleon-nucleon force, and to explore the transition from the nucleon-meson to a QCD description. Its success is based on the firm foundation of experimental and theoretical techniques developed world-wide over the past few decades, on complementary data provided by essential lower-energy facilities, such as MAMI, and on the many insights provided by the scientists we are gathered here to honor.

  7. A domain decomposition scheme for Eulerian shock physics codes

    SciTech Connect

    Bell, R.L.; Hertel, E.S. Jr.

    1994-08-01

    A new algorithm which allows for complex domain decomposition in Eulerian codes was developed at Sandia National Laboratories. This new feature allows a user to customize the zoning for each portion of a calculation and to refine volumes of the computational space of particular interest This option is available in one, two, and three dimensions. The new technique will be described in detail and several examples of the effectiveness of this technique will also be discussed.

  8. Atomic Structure Calculations from the Los Alamos Atomic Physics Codes

    DOE Data Explorer

    Cowan, R. D.

    The well known Hartree-Fock method of R.D. Cowan, developed at Los Alamos National Laboratory, is used for the atomic structure calculations. Electron impact excitation cross sections are calculated using either the distorted wave approximation (DWA) or the first order many body theory (FOMBT). Electron impact ionization cross sections can be calculated using the scaled hydrogenic method developed by Sampson and co-workers, the binary encounter method or the distorted wave method. Photoionization cross sections and, where appropriate, autoionizations are also calculated. Original manuals for the atomic structure code, the collisional excitation code, and the ionization code, are available from this website. Using the specialized interface, you will be able to define the ionization stage of an element and pick the initial and final configurations. You will be led through a series of web pages ending with a display of results in the form of cross sections, collision strengths or rates coefficients. Results are available in tabular and graphic form.

  9. Coupling MCNP-DSP and LAHET Monte Carlo Codes for Designing Subcriticality Monitors for Accelerator-Driven Systems

    SciTech Connect

    Valentine, T.E.; Rugama, Y. Munoz-Cobos, J.; Perez, R.

    2000-10-23

    The design of reactivity monitoring systems for accelerator-driven systems must be investigated to ensure that such systems remain subcritical during operation. The Monte Carlo codes LAHET and MCNP-DSP were combined together to facilitate the design of reactivity monitoring systems. The coupling of LAHET and MCNP-DSP provides a tool that can be used to simulate a variety of subcritical measurements such as the pulsed neutron, Rossi-{alpha}, or noise analysis measurements.

  10. Accelerating Innovation: How Nuclear Physics Benefits Us All

    SciTech Connect

    Not Available

    2011-01-01

    From fighting cancer to assuring food is safe to protecting our borders, nuclear physics impacts the lives of people around the globe every day. In learning about the nucleus of the atom and the forces that govern it, scientists develop a depth of knowledge, techniques and remarkable research tools that can be used to develop a variety of often unexpected, practical applications. These applications include devices and technologies for medical diagnostics and therapy, energy production and exploration, safety and national security, and for the analysis of materials and environmental contaminants. This brochure by the Office of Nuclear Physics of the USDOE Office of Science discusses nuclear physics and ways in which its applications fuel our economic vitality, and make the world and our lives safer and healthier.

  11. Simulations of an accelerator-based shielding experiment using the particle and heavy-ion transport code system PHITS.

    PubMed

    Sato, T; Sihver, L; Iwase, H; Nakashima, H; Niita, K

    2005-01-01

    In order to estimate the biological effects of HZE particles, an accurate knowledge of the physics of interaction of HZE particles is necessary. Since the heavy ion transport problem is a complex one, there is a need for both experimental and theoretical studies to develop accurate transport models. RIST and JAERI (Japan), GSI (Germany) and Chalmers (Sweden) are therefore currently developing and bench marking the General-Purpose Particle and Heavy-Ion Transport code System (PHITS), which is based on the NMTC and MCNP for nucleon/meson and neutron transport respectively, and the JAM hadron cascade model. PHITS uses JAERI Quantum Molecular Dynamics (JQMD) and the Generalized Evaporation Model (GEM) for calculations of fission and evaporation processes, a model developed at NASA Langley for calculation of total reaction cross sections, and the SPAR model for stopping power calculations. The future development of PHITS includes better parameterization in the JQMD model used for the nucleus-nucleus reactions, and improvement of the models used for calculating total reaction cross sections, and addition of routines for calculating elastic scattering of heavy ions, and inclusion of radioactivity and burn up processes. As a part of an extensive bench marking of PHITS, we have compared energy spectra of secondary neutrons created by reactions of HZE particles with different targets, with thicknesses ranging from <1 to 200 cm. We have also compared simulated and measured spatial, fluence and depth-dose distributions from different high energy heavy ion reactions. In this paper, we report simulations of an accelerator-based shielding experiment, in which a beam of 1 GeV/n Fe-ions has passed through thin slabs of polyethylene, Al, and Pb at an acceptance angle up to 4 degrees.

  12. Hadron physics at the new CW electron accelerators

    SciTech Connect

    Burkert, V.D.

    1990-01-01

    Major trends of the physics program related to the study of hadron structure and hadron spectroscopy at the new high current, high duty cycle electron machines are discussed. It is concluded that planned experiments at these machines may have important impact on our understanding of the strong interaction by studying the internal structure and spectroscopy of the nucleon and lower mass hyperon states.

  13. Proceedings of the workshop on B physics at hadron accelerators

    SciTech Connect

    McBride, P.; Mishra, C.S.

    1993-12-31

    This report contains papers on the following topics: Measurement of Angle {alpha}; Measurement of Angle {beta}; Measurement of Angle {gamma}; Other B Physics; Theory of Heavy Flavors; Charged Particle Tracking and Vertexing; e and {gamma} Detection; Muon Detection; Hadron ID; Electronics, DAQ, and Computing; and Machine Detector Interface. Selected papers have been indexed separately for inclusion the in Energy Science and Technology Database.

  14. ``Accelerators and Beams,'' multimedia computer-based training in accelerator physics

    NASA Astrophysics Data System (ADS)

    Silbar, R. R.; Browman, A. A.; Mead, W. C.; Williams, R. A.

    1999-06-01

    We are developing a set of computer-based tutorials on accelerators and charged-particle beams under an SBIR grant from the DOE. These self-paced, interactive tutorials, available for Macintosh and Windows platforms, use multimedia techniques to enhance the user's rate of learning and length of retention of the material. They integrate interactive "On-Screen Laboratories," hypertext, line drawings, photographs, two- and three-dimensional animations, video, and sound. They target a broad audience, from undergraduates or technicians to professionals. Presently, three modules have been published (Vectors, Forces, and Motion), a fourth (Dipole Magnets) has been submitted for review, and three more exist in prototype form (Quadrupoles, Matrix Transport, and Properties of Charged-Particle Beams). Participants in the poster session will have the opportunity to try out these modules on a laptop computer.

  15. Development of a coupled dynamics code with transport theory capability and application to accelerator driven systems transients

    SciTech Connect

    Cahalan, J. E.; Ama, T.; Palmiotti, G.; Taiwo, T. A.; Yang, W. S.

    2000-03-09

    The VARIANT-K and DIF3D-K nodal spatial kinetics computer codes have been coupled to the SAS4A and SASSYS-1 liquid metal reactor accident and systems analysis codes. SAS4A and SASSYS-1 have been extended with the addition of heavy liquid metal (Pb and Pb-Bi) thermophysical properties, heat transfer correlations, and fluid dynamics correlations. The coupling methodology and heavy liquid metal modeling additions are described. The new computer code suite has been applied to analysis of neutron source and thermal-hydraulics transients in a model of an accelerator-driven minor actinide burner design proposed in an OECD/NEA/NSC benchmark specification. Modeling assumptions and input data generation procedures are described. Results of transient analyses are reported, with emphasis on comparison of P1 and P3 variational nodal transport theory results with nodal diffusion theory results, and on significance of spatial kinetics effects.

  16. MIG version 0.0 model interface guidelines: Rules to accelerate installation of numerical models into any compliant parent code

    SciTech Connect

    Brannon, R.M.; Wong, M.K.

    1996-08-01

    A set of model interface guidelines, called MIG, is presented as a means by which any compliant numerical material model can be rapidly installed into any parent code without having to modify the model subroutines. Here, {open_quotes}model{close_quotes} usually means a material model such as one that computes stress as a function of strain, though the term may be extended to any numerical operation. {open_quotes}Parent code{close_quotes} means a hydrocode, finite element code, etc. which uses the model and enforces, say, the fundamental laws of motion and thermodynamics. MIG requires the model developer (who creates the model package) to specify model needs in a standardized but flexible way. MIG includes a dictionary of technical terms that allows developers and parent code architects to share a common vocabulary when specifying field variables. For portability, database management is the responsibility of the parent code. Input/output occurs via structured calling arguments. As much model information as possible (such as the lists of required inputs, as well as lists of precharacterized material data and special needs) is supplied by the model developer in an ASCII text file. Every MIG-compliant model also has three required subroutines to check data, to request extra field variables, and to perform model physics. To date, the MIG scheme has proven flexible in beta installations of a simple yield model, plus a more complicated viscodamage yield model, three electromechanical models, and a complicated anisotropic microcrack constitutive model. The MIG yield model has been successfully installed using identical subroutines in three vectorized parent codes and one parallel C++ code, all predicting comparable results. By maintaining one model for many codes, MIG facilitates code-to-code comparisons and reduces duplication of effort, thereby reducing the cost of installing and sharing models in diverse new codes.

  17. Report of the Subpanel on Accelerator Research and Development of the High Energy Physics Advisory Panel

    SciTech Connect

    Not Available

    1980-06-01

    Accelerator R and D in the US High Energy Physics (HEP) program is reviewed. As a result of this study, some shift in priority, particularly as regards long-range accelerator R and D, is suggested to best serve the future needs of the US HEP program. Some specific new directions for the US R and D effort are set forth. 18 figures, 5 tables. (RWR)

  18. High energy physics advisory panel`s composite subpanel for the assessment of the status of accelerator physics and technology

    SciTech Connect

    1996-05-01

    In November 1994, Dr. Martha Krebs, Director of the US Department of Energy (DOE) Office of Energy Research (OER), initiated a broad assessment of the current status and promise of the field of accelerator physics and technology with respect to five OER programs -- High Energy Physics, Nuclear Physics, Basic Energy Sciences, Fusion Energy, and Health and Environmental Research. Dr. Krebs asked the High Energy Physics Advisory Panel (HEPAP) to establish a composite subpanel with representation from the five OER advisory committees and with a balance of membership drawn broadly from both the accelerator community and from those scientific disciplines associated with the OER programs. The Subpanel was also charged to provide recommendations and guidance on appropriate future research and development needs, management issues, and funding requirements. The Subpanel finds that accelerator science and technology is a vital and intellectually exciting field. It has provided essential capabilities for the DOE/OER research programs with an enormous impact on the nation`s scientific research, and it has significantly enhanced the nation`s biomedical and industrial capabilities. Further progress in this field promises to open new possibilities for the scientific goals of the OER programs and to further benefit the nation. Sustained support of forefront accelerator research and development by the DOE`s OER programs and the DOE`s predecessor agencies has been responsible for much of this impact on research. This report documents these contributions to the DOE energy research mission and to the nation.

  19. Proceedings of the 1998 International Computational Accelerator Physics Conference (ICAP98)

    NASA Astrophysics Data System (ADS)

    Ko, K.

    2002-01-01

    The CLASSIC library is a C++ class library which provides services for building portable accelerator models and algorithms for their analysis. This paper describes the motivations behind the CLASSIC library and its main features. It shows how this library can be used in a large accelerator design program like the new version 9 of MAD written in C++. The possibilities are illustrated by presenting some new developments in MAD version 9, like sophisticated matching features with simultaneous matching of two rings. The major part of the CLASSIC library is now implemented. Its source code and some preliminary documentation are available from the author.

  20. Physics design and scaling of recirculating induction accelerators: from benchtop prototypes to drivers

    SciTech Connect

    Barnard, J.J.; Cable, M.D.; Callahan, D.A.

    1996-02-06

    Recirculating induction accelerators (recirculators) have been investigated as possible drivers for inertial fusion energy production because of their potential cost advantage over linear induction accelerators. Point designs were obtained and many of the critical physics and technology issues that would need to be addressed were detailed. A collaboration involving Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory researchers is now developing a small prototype recirculator in order to demonstrate an understanding of nearly all of the critical beam dynamics issues that have been raised. We review the design equations for recirculators and demonstrate how, by keeping crucial dimensionless quantities constant, a small prototype recirculator was designed which will simulate the essential beam physics of a driver. We further show how important physical quantities such as the sensitivity to errors of optical elements (in both field strength and placement), insertion/extraction, vacuum requirements, and emittance growth, scale from small-prototype to driver-size accelerator.

  1. Development of a relativistic Particle In Cell code PARTDYN for linear accelerator beam transport

    NASA Astrophysics Data System (ADS)

    Phadte, D.; Patidar, C. B.; Pal, M. K.

    2017-04-01

    A relativistic Particle In Cell (PIC) code PARTDYN is developed for the beam dynamics simulation of z-continuous and bunched beams. The code is implemented in MATLAB using its MEX functionality which allows both ease of development as well higher performance similar to a compiled language like C. The beam dynamics calculations carried out by the code are compared with analytical results and with other well developed codes like PARMELA and BEAMPATH. The effect of finite number of simulation particles on the emittance growth of intense beams has been studied. Corrections to the RF cavity field expressions were incorporated in the code so that the fields could be calculated correctly. The deviations of the beam dynamics results between PARTDYN and BEAMPATH for a cavity driven in zero-mode have been discussed. The beam dynamics studies of the Low Energy Beam Transport (LEBT) using PARTDYN have been presented.

  2. The MARS15-based FermiCORD Code System for Calculation of the Accelerator-Induced Residual Dose

    SciTech Connect

    Grebe, A.; Leveling, A.; Lu, T.; Mokhov, N.; Pronskikh, V.

    2016-09-01

    The FermiCORD code system, a set of codes based on MARS15 that calculates the accelerator-induced residual doses at experimental facilities of arbitrary configurations, has been developed. FermiCORD is written in C++ as an add-on to Fortran-based MARS15. The FermiCORD algorithm consists of two stages: 1) simulation of residual doses on contact with the surfaces surrounding the studied location and of radionuclide inventories in the structures surrounding those locations using MARS15, and 2) simulation of the emission of the nuclear decay gamma-quanta by the residuals in the activated structures and scoring the prompt doses of these gamma-quanta at arbitrary distances from those structures. The FermiCORD code system has been benchmarked against similar algorithms based on other code systems and showed a good agreement. The code system has been applied for calculation of the residual dose of the target station for the Mu2e experiment and the results have been compared to approximate dosimetric approaches.

  3. Deep ocean mineral water accelerates recovery from physical fatigue

    PubMed Central

    2013-01-01

    Background Deep oceans have been suggested as a possible site where the origin of life occurred. Along with this theoretical lineage, experiments using components from deep ocean water to recreate life is underway. Here, we propose that if terrestrial organisms indeed evolved from deep oceans, supply of deep ocean mineral water (DOM) to humans, as a land creature, may replenish loss of molecular complexity associated with evolutionary sea-to-land migration. Methods We conducted a randomized, double-blind, placebo-controlled crossover human study to evaluate the effect of DOM, taken from a depth of 662 meters off the coast of Hualien, Taiwan, on time of recovery from a fatiguing exercise conducted at 30°C. Results The fatiguing exercise protocol caused a protracted reduction in aerobic power (reduced VO2max) for 48 h. However, DOM supplementation resulted in complete recovery of aerobic power within 4 h (P < 0.05). Muscle power was also elevated above placebo levels within 24 h of recovery (P < 0.05). Increased circulating creatine kinase (CK) and myoglobin, indicatives of exercise-induced muscle damage, were completely eliminated by DOM (P < 0.05) in parallel with attenuated oxidative damage (P < 0.05). Conclusion Our results provide compelling evidence that DOM contains soluble elements, which can increase human recovery following an exhaustive physical challenge. PMID:23402436

  4. Physics of Double Pulse Irradiation of Targets For Proton Acceleration

    NASA Astrophysics Data System (ADS)

    Kerr, S.; Mo, M.; Masud, R.; Manzoor, L.; Tiedje, H.; Tsui, Y.; Fedosejevs, R.; Link, A.; Patel, P.; McLean, H.; Hazi, A.; Chen, H.; Ceurvorst, L.; Norreys, P.

    2016-10-01

    Experiments have been carried out on double-pulse irradiation of um-scale foil targets with varying preplasma conditions. Our experiment at the Titan Laser facility utilized two 700 fs, 1054 nm pulses, separated by 1 to 5 ps with a total energy of 100 J, and with 5-20% of the total energy contained within the first pulse. The proton spectra were measured with radiochromic film stacks and magnetic spectrometers. The prepulse energy was on the order of 10 mJ, which appears to have a moderating effect on the double pulse enhancement of proton beam. We have performed LSP PIC simulations to understand the double pulse enhancement mechanism, as well as the role of preplasma in modifying the interaction. A 1D parameter study was done to isolate various aspects of the interaction, while 2D simulations provide more detailed physical insight and a better comparison with experimental data. Work by the Univ. of Alberta was supported by the Natural Sciences and Engineering Research Council of Canada. Work by LLNL was performed under the auspices of U.S. DOE under contract DE-AC52-07NA27344.

  5. State of particle accelerators and high energy physics (Fermilab Summer School, 1981). Part 2

    SciTech Connect

    Carrigan, R.A. Jr.; Huson, F.R.; Month, M.

    1982-01-01

    The material gathered in this volume covers the seminars given at the Summer School on High Energy Particle Accelerators, sponsored by the United States Department of Energy (DOE) and the National Science Foundation, held at Fermilab in Batavia, Illinois, July 13 to 24, 1981. The school was organized as a response to a recent appeal by a subpanel of the DOE High Energy Physics Advisory Panel (HEPAP) for more scientists and more students to work in the field of high energy particle accelerators. The committee set a number of objectives for the school: (1) to present in a thorough and up-to-date manner the entire spectrum of knowledge relating to accelerators; (2) to disseminate that knowledge to audiences that can best make use of it; (3) to encourage, by providing text materials and training to potential instructors, the development of accelerator physics education as part of university programs in high-energy physics; and (4) to foster a more extensive dialogue between particle and accelerator physicists. Separate entries were prepared for the data base for the papers included. (WHK)

  6. Neutron sources in the Varian Clinac 2100C/2300C medical accelerator calculated by the EGS4 code.

    PubMed

    Mao, X S; Kase, K R; Liu, J C; Nelson, W R; Kleck, J H; Johnsen, S

    1997-04-01

    The photoneutron yields produced in different components of the medical accelerator heads evaluated in these studies (24-MV Clinac 2500 and a Clinac 2100C/2300C running in the 10-MV, 15-MV, 18-MV and 20-MV modes) were calculated by the EGS4 Monte Carlo code using a modified version of the Combinatorial Geometry of MORSE-CG. Actual component dimensions and materials (i.e., targets, collimators, flattening filters, jaws and shielding for specific accelerator heads) were used in the geometric simulations. Calculated relative neutron yields in different components of a 24-MV Clinac 2500 were compared with the published measured data, and were found to agree to within +/-30%. Total neutron yields produced in the Clinac 2100/2300, as a function of primary electron energy and field size, are presented. A simplified Clinac 2100/2300C geometry is presented to calculate neutron yields, which were compared with those calculated by using the fully-described geometry.

  7. Pyroelectric Crystal Accelerator In The Department Of Physics And Nuclear Engineering At West Point

    NASA Astrophysics Data System (ADS)

    Gillich, Don; Shannon, Mike; Kovanen, Andrew; Anderson, Tom; Bright, Kevin; Edwards, Ronald; Danon, Yaron; Moretti, Brian; Musk, Jeffrey

    2011-06-01

    The Nuclear Science and Engineering Research Center (NSERC), a Defense Threat Reduction Agency (DTRA) office located at the United States Military Academy (USMA), sponsors and manages cadet and faculty research in support of DTRA objectives. The NSERC has created an experimental pyroelectric crystal accelerator program to enhance undergraduate education at USMA in the Department of Physics and Nuclear Engineering. This program provides cadets with hands-on experience in designing their own experiments using an inexpensive tabletop accelerator. This device uses pyroelectric crystals to ionize and accelerate gas ions to energies of ˜100 keV. Within the next year, cadets and faculty at USMA will use this device to create neutrons through the deuterium-deuterium (D-D) fusion process, effectively creating a compact, portable neutron generator. The double crystal pyroelectric accelerator will also be used by students to investigate neutron, x-ray, and ion spectroscopy.

  8. CTH: A three-dimensional shock wave physics code

    NASA Astrophysics Data System (ADS)

    McGlaun, J. Michael; Thompson, S. L.; Elrick, M. G.

    CTH is a software system under development at Sandia National Laboratories, Albuquerque, to model multidimensional, multi-material, large deformation, strong shock wave physics. One-dimensional rectilinear, cylindrical, and spherical meshes; 2-D rectangular, and cylindrical meshes; and 3-D rectangular meshes are currently available. A two-step Eulerian solution scheme is used with these meshes. The first step is a Lagrangian step in which the cells distort to follow the material motion. The second step is a remesh step where the distorted cells are mapped back to the Eulerian mesh. CTH has several models that are useful for simulating strong shock, large deformation events. Both tabular and analytic equations of state are available. CTH can model elastic-plastic behavior, high explosive detonation, fracture, and motion of fragments smaller than a computational cell. The elastic-plastic model is elastic-perfectly plastic with thermal softening. A programmed burn model is available for modelling high explosive detonation. The Jones-Wilkins-Lee equation of state is available for modelling high explosive reaction products. Fracture can be initiated based on pressure or principle stress. A special model is available for moving fragments smaller than a computational cell with statistically the correct velocity. This model is very useful for analyzing fragmentation experiments and experiments with witness plates. The models, and novel features of CTH are described. Special emphasis is placed on the features that are novel to CTH or are not direct generalizations of 2-D models. Another paper by Trucano and McGlaun describes several hypervelocity impact calculations using CTH.

  9. Physical Interpretation of the Schott Energy of An Accelerating Point Charge and the Question of Whether a Uniformly Accelerating Charge Radiates

    ERIC Educational Resources Information Center

    Rowland, David R.

    2010-01-01

    A core topic in graduate courses in electrodynamics is the description of radiation from an accelerated charge and the associated radiation reaction. However, contemporary papers still express a diversity of views on the question of whether or not a uniformly accelerating charge radiates suggesting that a complete "physical" understanding of the…

  10. Physics with a high-intensity proton accelerator below 30 GeV

    SciTech Connect

    Hoffman, C.M.

    1982-01-01

    The types of physics that would be pursued at a high-intensity, moderate-energy proton accelerator are discussed. The discussion is drawn from the deliberations of the 30-GeV subgroup of the Fixed-Target Group at this workshop.

  11. Multi-threaded acceleration of ORBIT code on CPU and GPU with minimal modifications

    NASA Astrophysics Data System (ADS)

    Qu, Ante; Ethier, Stephane; Feibush, Eliot; White, Roscoe

    2013-10-01

    The guiding center code ORBIT was originally developed 30 years ago to study the drift orbit effects of charged particles in the strong equilibrium magnetic fields of tokamaks. Today, ORBIT remains a very active tool in magnetic confinement fusion research and continues to adapt to the latest toroidal devices, such as the NSTX-Upgrade, for which it plays a very important role in the study of energetic particle effects. Although the capabilities of ORBIT have improved throughout the years, the code still remains a serial application, which has now become an impediment to the lengthy simulations required for the NSTX-U project. In this work, multi-threaded parallelism is introduced in the core of the code with the goal of achieving the largest performance improvement while minimizing changes made to the source code. To that end, we introduce preprocessor directives in the most compute-intensive parts of the code, which constitute the stable core that seldom changes. Standard OpenMP directives are used for shared-memory CPU multi-threading while newly developed OpenACC (www.openacc.org) directives are used for GPU (Graphical Processing Unit) multi-threading. Implementation details and performance results are presented.

  12. Two-dimensional spatiotemporal coding of linear acceleration in vestibular nuclei neurons

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Bush, G. A.; Perachio, A. A.

    1993-01-01

    Response properties of vertical (VC) and horizontal (HC) canal/otolith-convergent vestibular nuclei neurons were studied in decerebrate rats during stimulation with sinusoidal linear accelerations (0.2-1.4 Hz) along different directions in the head horizontal plane. A novel characteristic of the majority of tested neurons was the nonzero response often elicited during stimulation along the "null" direction (i.e., the direction perpendicular to the maximum sensitivity vector, Smax). The tuning ratio (Smin gain/Smax gain), a measure of the two-dimensional spatial sensitivity, depended on stimulus frequency. For most vestibular nuclei neurons, the tuning ratio was small at the lowest stimulus frequencies and progressively increased with frequency. Specifically, HC neurons were characterized by a flat Smax gain and an approximately 10-fold increase of Smin gain per frequency decade. Thus, these neurons encode linear acceleration when stimulated along their maximum sensitivity direction, and the rate of change of linear acceleration (jerk) when stimulated along their minimum sensitivity direction. While the Smax vectors were distributed throughout the horizontal plane, the Smin vectors were concentrated mainly ipsilaterally with respect to head acceleration and clustered around the naso-occipital head axis. The properties of VC neurons were distinctly different from those of HC cells. The majority of VC cells showed decreasing Smax gains and small, relatively flat, Smin gains as a function of frequency. The Smax vectors were distributed ipsilaterally relative to the induced (apparent) head tilt. In type I anterior or posterior VC neurons, Smax vectors were clustered around the projection of the respective ipsilateral canal plane onto the horizontal head plane. These distinct spatial and temporal properties of HC and VC neurons during linear acceleration are compatible with the spatiotemporal organization of the horizontal and the vertical/torsional ocular responses

  13. Digitized forensics: retaining a link between physical and digital crime scene traces using QR-codes

    NASA Astrophysics Data System (ADS)

    Hildebrandt, Mario; Kiltz, Stefan; Dittmann, Jana

    2013-03-01

    The digitization of physical traces from crime scenes in forensic investigations in effect creates a digital chain-of-custody and entrains the challenge of creating a link between the two or more representations of the same trace. In order to be forensically sound, especially the two security aspects of integrity and authenticity need to be maintained at all times. Especially the adherence to the authenticity using technical means proves to be a challenge at the boundary between the physical object and its digital representations. In this article we propose a new method of linking physical objects with its digital counterparts using two-dimensional bar codes and additional meta-data accompanying the acquired data for integration in the conventional documentation of collection of items of evidence (bagging and tagging process). Using the exemplary chosen QR-code as particular implementation of a bar code and a model of the forensic process, we also supply a means to integrate our suggested approach into forensically sound proceedings as described by Holder et al.1 We use the example of the digital dactyloscopy as a forensic discipline, where currently progress is being made by digitizing some of the processing steps. We show an exemplary demonstrator of the suggested approach using a smartphone as a mobile device for the verification of the physical trace to extend the chain-of-custody from the physical to the digital domain. Our evaluation of the demonstrator is performed towards the readability and the verification of its contents. We can read the bar code despite its limited size of 42 x 42 mm and rather large amount of embedded data using various devices. Furthermore, the QR-code's error correction features help to recover contents of damaged codes. Subsequently, our appended digital signature allows for detecting malicious manipulations of the embedded data.

  14. Use of color-coded sleeve shutters accelerates oscillograph channel selection

    NASA Technical Reports Server (NTRS)

    Bouchlas, T.; Bowden, F. W.

    1967-01-01

    Sleeve-type shutters mechanically adjust individual galvanometer light beams onto or away from selected channels on oscillograph papers. In complex test setups, the sleeve-type shutters are color coded to separately identify each oscillograph channel. This technique could be used on any equipment using tubular galvanometer light sources.

  15. Accelerator physics and technology challenges of very high energy hadron colliders

    DOE PAGES

    Shiltsev, Vladimir D.

    2015-08-20

    High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton–proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This article briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

  16. Accelerator physics and technology challenges of very high energy hadron colliders

    NASA Astrophysics Data System (ADS)

    Shiltsev, Vladimir D.

    2015-08-01

    High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton-proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This paper briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

  17. PIC codes for plasma accelerators on emerging computer architectures (GPUS, Multicore/Manycore CPUS)

    NASA Astrophysics Data System (ADS)

    Vincenti, Henri

    2016-03-01

    The advent of exascale computers will enable 3D simulations of a new laser-plasma interaction regimes that were previously out of reach of current Petasale computers. However, the paradigm used to write current PIC codes will have to change in order to fully exploit the potentialities of these new computing architectures. Indeed, achieving Exascale computing facilities in the next decade will be a great challenge in terms of energy consumption and will imply hardware developments directly impacting our way of implementing PIC codes. As data movement (from die to network) is by far the most energy consuming part of an algorithm future computers will tend to increase memory locality at the hardware level and reduce energy consumption related to data movement by using more and more cores on each compute nodes (''fat nodes'') that will have a reduced clock speed to allow for efficient cooling. To compensate for frequency decrease, CPU machine vendors are making use of long SIMD instruction registers that are able to process multiple data with one arithmetic operator in one clock cycle. SIMD register length is expected to double every four years. GPU's also have a reduced clock speed per core and can process Multiple Instructions on Multiple Datas (MIMD). At the software level Particle-In-Cell (PIC) codes will thus have to achieve both good memory locality and vectorization (for Multicore/Manycore CPU) to fully take advantage of these upcoming architectures. In this talk, we present the portable solutions we implemented in our high performance skeleton PIC code PICSAR to both achieve good memory locality and cache reuse as well as good vectorization on SIMD architectures. We also present the portable solutions used to parallelize the Pseudo-sepctral quasi-cylindrical code FBPIC on GPUs using the Numba python compiler.

  18. Induction-accelerator heavy-ion fusion: Status and beam physics issues

    SciTech Connect

    Friedman, A.

    1996-01-26

    Inertial confinement fusion driven by beams of heavy ions is an attractive route to controlled fusion. In the U.S., induction accelerators are being developed as {open_quotes}drivers{close_quotes} for this process. This paper is divided into two main sections. In the first section, the concept of induction-accelerator driven heavy-ion fusion is briefly reviewed, and the U.S. program of experiments and theoretical investigations is described. In the second, a {open_quotes}taxonomy{close_quotes} of space-charge-dominated beam physics issues is presented, accompanied by a brief discussion of each area.

  19. Physical Activities Monitoring Using Wearable Acceleration Sensors Attached to the Body.

    PubMed

    Arif, Muhammad; Kattan, Ahmed

    2015-01-01

    Monitoring physical activities by using wireless sensors is helpful for identifying postural orientation and movements in the real-life environment. A simple and robust method based on time domain features to identify the physical activities is proposed in this paper; it uses sensors placed on the subjects' wrist, chest and ankle. A feature set based on time domain characteristics of the acceleration signal recorded by acceleration sensors is proposed for the classification of twelve physical activities. Nine subjects performed twelve different types of physical activities, including sitting, standing, walking, running, cycling, Nordic walking, ascending stairs, descending stairs, vacuum cleaning, ironing clothes and jumping rope, and lying down (resting state). Their ages were 27.2 ± 3.3 years and their body mass index (BMI) is 25.11 ± 2.6 Kg/m2. Classification results demonstrated a high validity showing precision (a positive predictive value) and recall (sensitivity) of more than 95% for all physical activities. The overall classification accuracy for a combined feature set of three sensors is 98%. The proposed framework can be used to monitor the physical activities of a subject that can be very useful for the health professional to assess the physical activity of healthy individuals as well as patients.

  20. Physical Activities Monitoring Using Wearable Acceleration Sensors Attached to the Body

    PubMed Central

    2015-01-01

    Monitoring physical activities by using wireless sensors is helpful for identifying postural orientation and movements in the real-life environment. A simple and robust method based on time domain features to identify the physical activities is proposed in this paper; it uses sensors placed on the subjects’ wrist, chest and ankle. A feature set based on time domain characteristics of the acceleration signal recorded by acceleration sensors is proposed for the classification of twelve physical activities. Nine subjects performed twelve different types of physical activities, including sitting, standing, walking, running, cycling, Nordic walking, ascending stairs, descending stairs, vacuum cleaning, ironing clothes and jumping rope, and lying down (resting state). Their ages were 27.2 ± 3.3 years and their body mass index (BMI) is 25.11 ± 2.6 Kg/m2. Classification results demonstrated a high validity showing precision (a positive predictive value) and recall (sensitivity) of more than 95% for all physical activities. The overall classification accuracy for a combined feature set of three sensors is 98%. The proposed framework can be used to monitor the physical activities of a subject that can be very useful for the health professional to assess the physical activity of healthy individuals as well as patients. PMID:26203909

  1. A lightweight in situ visualization and analysis infrastructure for multi-physics HPC simulation codes

    SciTech Connect

    Harrison, Cyrus; Larsen, Matt; Brugger, Eric

    2016-12-05

    Strawman is a system designed to explore the in situ visualization and analysis needs of simulation code teams running multi-physics calculations on many-core HPC architectures. It porvides rendering pipelines that can leverage both many-core CPUs and GPUs to render images of simulation meshes.

  2. Modern Teaching Methods in Physics with the Aid of Original Computer Codes and Graphical Representations

    ERIC Educational Resources Information Center

    Ivanov, Anisoara; Neacsu, Andrei

    2011-01-01

    This study describes the possibility and advantages of utilizing simple computer codes to complement the teaching techniques for high school physics. The authors have begun working on a collection of open source programs which allow students to compare the results and graphics from classroom exercises with the correct solutions and further more to…

  3. Future accelerators (?)

    SciTech Connect

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  4. Can low-energy electrons affect high-energy physics accelerators?

    SciTech Connect

    Cimino, R.; Collins, I.R.; Furman, M.A.; Pivi, M.; Ruggiero, F.; Rumolo, G.; Zimmermann, F.

    2004-02-09

    Present and future accelerators performances may be limited by the electron cloud (EC) effect. The EC formation and evolution are determined by the wall-surface properties of the accelerator vacuum chamber.We present measurements of the total secondary electron yield (SEY) and the related energy distribution curves of the secondary electrons as a function of incident-electron energy. Particular attention has been paid to the emission process due to very low-energy primary electrons (<20 eV). It is shown that the SEY approaches unity and the reflected electron component is predominant in the limit of zero primary incident electron energy. Motivated by these measurements, we have used state-of-the-art EC simulation codes to predict how these results may impact the production of the electron cloud in the Large Hadron Collider, under construction at CERN, and the related surface heat load.

  5. Is a Coded Physical Activity Diary Valid for Assessing Physical Activity Level and Energy Expenditure in Stroke Patients?

    PubMed Central

    Vanroy, Christel; Vanlandewijck, Yves; Cras, Patrick; Feys, Hilde; Truijen, Steven; Michielsen, Marc; Vissers, Dirk

    2014-01-01

    Objectives to determine the concurrent validity of a physical activity diary for measuring physical activity level and total energy expenditure in hospitalized stroke patients. Method Sixteen stroke patients kept coded activity diaries and wore SenseWear Pro2 multi-sensor activity monitors during daytime hours for one day. A researcher observed the patients and completed a diary. Data from the patients' diaries were compared with observed and measured data to determine total activity (METs*minutes), activity level and total energy expenditure. Results Spearman correlations between the patients' and researchers' diaries revealed a high correlation for total METs*minutes (rs = 0.75, p<0.01) for sedentary (rs = 0.74,p<0.01) and moderate activities (rs = 0.71,p<0.01) and a very high correlation (rs = 0.92, p<0.01) for the total energy expenditure. Comparisons between the patients' diaries and activity monitor data revealed a low correlation (rs 0.29) for total METs*minutes and energy expenditure. Conclusion Coded self-monitoring activity diaries appear feasible as a low-tech alternative to labor-intensive observational diaries for determining sedentary, moderate, and total physical activity and for quantifying energy expenditure in hospitalized stroke patients. Given the poor correlation with objective measurements of physical activity, however, further research is needed to validate its use against a gold-standard measure of physical activity intensity and energy expenditure. PMID:24905345

  6. Multicore and Accelerator Development for a Leadership-Class Stellar Astrophysics Code

    SciTech Connect

    Messer, Bronson; Harris, James A; Parete-Koon, Suzanne T; Chertkow, Merek A

    2013-01-01

    We describe recent development work on the core-collapse supernova code CHIMERA. CHIMERA has consumed more than 100 million cpu-hours on Oak Ridge Leadership Computing Facility (OLCF) platforms in the past 3 years, ranking it among the most important applications at the OLCF. Most of the work described has been focused on exploiting the multicore nature of the current platform (Jaguar) via, e.g., multithreading using OpenMP. In addition, we have begun a major effort to marshal the computational power of GPUs with CHIMERA. The impending upgrade of Jaguar to Titan a 20+ PF machine with an NVIDIA GPU on many nodes makes this work essential.

  7. The GENGA Code: Gravitational Encounters in N-body simulations with GPU Acceleration.

    NASA Astrophysics Data System (ADS)

    Grimm, Simon; Stadel, Joachim

    2013-07-01

    We present a GPU (Graphics Processing Unit) implementation of a hybrid symplectic N-body integrator based on the Mercury Code (Chambers 1999), which handles close encounters with a very good energy conservation. It uses a combination of a mixed variable integration (Wisdom & Holman 1991) and a direct N-body Bulirsch-Stoer method. GENGA is written in CUDA C and runs on NVidia GPU's. The GENGA code supports three simulation modes: Integration of up to 2048 massive bodies, integration with up to a million test particles, or parallel integration of a large number of individual planetary systems. To achieve the best performance, GENGA runs completely on the GPU, where it can take advantage of the very fast, but limited, memory that exists there. All operations are performed in parallel, including the close encounter detection and grouping independent close encounter pairs. Compared to Mercury, GENGA runs up to 30 times faster. Two applications of GENGA are presented: First, the dynamics of planetesimals and the late stage of rocky planet formation due to planetesimal collisions. Second, a dynamical stability analysis of an exoplanetary system with an additional hypothetical super earth, which shows that in some multiple planetary systems, additional super earths could exist without perturbing the dynamical stability of the other planets (Elser et al. 2013).

  8. European Code against Cancer 4th Edition: Physical activity and cancer.

    PubMed

    Leitzmann, Michael; Powers, Hilary; Anderson, Annie S; Scoccianti, Chiara; Berrino, Franco; Boutron-Ruault, Marie-Christine; Cecchini, Michele; Espina, Carolina; Key, Timothy J; Norat, Teresa; Wiseman, Martin; Romieu, Isabelle

    2015-12-01

    Physical activity is a complex, multidimensional behavior, the precise measurement of which is challenging in free-living individuals. Nonetheless, representative survey data show that 35% of the European adult population is physically inactive. Inadequate levels of physical activity are disconcerting given substantial epidemiologic evidence showing that physical activity is associated with decreased risks of colon, endometrial, and breast cancers. For example, insufficient physical activity levels are thought to cause 9% of breast cancer cases and 10% of colon cancer cases in Europe. By comparison, the evidence for a beneficial effect of physical activity is less consistent for cancers of the lung, pancreas, ovary, prostate, kidney, and stomach. The biologic pathways underlying the association between physical activity and cancer risk are incompletely defined, but potential etiologic pathways include insulin resistance, growth factors, adipocytokines, steroid hormones, and immune function. In recent years, sedentary behavior has emerged as a potential independent determinant of cancer risk. In cancer survivors, physical activity has shown positive effects on body composition, physical fitness, quality of life, anxiety, and self-esteem. Physical activity may also carry benefits regarding cancer survival, but more evidence linking increased physical activity to prolonged cancer survival is needed. Future studies using new technologies - such as accelerometers and e-tools - will contribute to improved assessments of physical activity. Such advancements in physical activity measurement will help clarify the relationship between physical activity and cancer risk and survival. Taking the overall existing evidence into account, the fourth edition of the European Code against Cancer recommends that people be physically active in everyday life and limit the time spent sitting.

  9. Dust in tokamaks: An overview of the physical model of the dust in tokamaks code

    NASA Astrophysics Data System (ADS)

    Bacharis, Minas; Coppins, Michael; Allen, John E.

    2010-04-01

    The dynamical behavior of dust produced in tokamaks is an important issue for fusion. In this work, the current status of the dust in tokamaks (DTOKS) [J. D. Martin et al., Europhys Lett. 83, 65001 (2008)] dust transport code will be presented. A detailed description of the various elements of its underlying physical model will be given together with representative simulation results for the mega amp spherical tokamak (MAST) [A. Sykes et al., Nucl. Fusion 41, 1423 (2001)]. Furthermore, a brief description of the various components of the dust transport (DUSTT) [R. D. Smirnov et al., Plasma Phys. Controlled Fusion 49, 347 (2007)] code will also be presented in comparison with DTOKS.

  10. Diagnosis of weaknesses in modern error correction codes: a physics approach.

    PubMed

    Stepanov, M G; Chernyak, V; Chertkov, M; Vasic, B

    2005-11-25

    One of the main obstacles to the wider use of the modern error-correction codes is that, due to the complex behavior of their decoding algorithms, no systematic method which would allow characterization of the bit-error-rate (BER) is known. This is especially true at the weak noise where many systems operate and where coding performance is difficult to estimate because of the diminishingly small number of errors. We show how the instanton method of physics allows one to solve the problem of BER analysis in the weak noise range by recasting it as a computationally tractable minimization problem.

  11. Design of the main racetrack microtron accelerator end magnets of the Institute of Physics of University of São Paulo

    NASA Astrophysics Data System (ADS)

    Kassab, L. R.; Martins, M. N.; Takahashi, J.; Gouffon, P.

    1999-03-01

    This work deals with the design of the Institute of Physics of the University of São Paulo (IFUSP) main racetrack microtron accelerator end magnets. This is the last stage of acceleration, comprised of an accelerating section (1.04 m) and two end magnets (0.1585 T), in which a 5.10 MeV beam, produced by a racetrack microtron booster has its energy raised up to 31.15 MeV after 28 accelerations. Poisson code was used to give the final configuration that includes auxiliary pole pieces (clamps) and auxiliary homogenizing gaps. The clamps create a reverse fringe field region and avoid the vertical defocusing and the horizontal displacement of the beam produced by extended fringe fields; Ptrace code was used to perform the trajectory calculations in the fringe field region. The auxiliary homogenizing gaps improve the field uniformity as they create a ``magnetic shower'' that provides uniformity of +/-0.3%, before the introduction of the correcting coils that will be attached to the pole faces. This method of correction, used in the IFUSP racetrack microtron booster magnets, enabled uniformity of +/-0.001% in an average field of 0.1 T and will also be employed for these end magnets.

  12. Monte Carlo Simulation of Siemens ONCOR Linear Accelerator with BEAMnrc and DOSXYZnrc Code.

    PubMed

    Jabbari, Keyvan; Anvar, Hossein Saberi; Tavakoli, Mohammad Bagher; Amouheidari, Alireza

    2013-07-01

    The Monte Carlo method is the most accurate method for simulation of radiation therapy equipment. The linear accelerators (linac) are currently the most widely used machines in radiation therapy centers. In this work, a Monte Carlo modeling of the Siemens ONCOR linear accelerator in 6 MV and 18 MV beams was performed. The results of simulation were validated by measurements in water by ionization chamber and extended dose range (EDR2) film in solid water. The linac's X-ray particular are so sensitive to the properties of primary electron beam. Square field size of 10 cm × 10 cm produced by the jaws was compared with ionization chamber and film measurements. Head simulation was performed with BEAMnrc and dose calculation with DOSXYZnrc for film measurements and 3ddose file produced by DOSXYZnrc analyzed used homemade MATLAB program. At 6 MV, the agreement between dose calculated by Monte Carlo modeling and direct measurement was obtained to the least restrictive of 1%, even in the build-up region. At 18 MV, the agreement was obtained 1%, except for in the build-up region. In the build-up region, the difference was 1% at 6 MV and 2% at 18 MV. The mean difference between measurements and Monte Carlo simulation is very small in both of ONCOR X-ray energy. The results are highly accurate and can be used for many applications such as patient dose calculation in treatment planning and in studies that model this linac with small field size like intensity-modulated radiation therapy technique.

  13. The FLUKA Code: an Overview

    SciTech Connect

    Ballarini, F.; Battistoni, G.; Campanella, M.; Carboni, M.; Cerutti, F.; Empl, A.; Fasso, A.; Ferrari, A.; Gadioli, E.; Garzelli, M.V.; Lantz, M.; Liotta, M.; Mairani, A.; Mostacci, A.; Muraro, S.; Ottolenghi, A.; Pelliccioni, M.; Pinsky, L.; Ranft, J.; Roesler, S.; Sala, P.R.; /Milan U. /INFN, Milan /Pavia U. /INFN, Pavia /CERN /Siegen U. /Houston U. /SLAC /Frascati /NASA, Houston /ENEA, Frascati

    2005-11-09

    FLUKA is a multipurpose Monte Carlo code which can transport a variety of particles over a wide energy range in complex geometries. The code is a joint project of INFN and CERN: part of its development is also supported by the University of Houston and NASA. FLUKA is successfully applied in several fields, including but not only, particle physics, cosmic ray physics, dosimetry, radioprotection, hadron therapy, space radiation, accelerator design and neutronics. The code is the standard tool used at CERN for dosimetry, radioprotection and beam-machine interaction studies. Here we give a glimpse into the code physics models with a particular emphasis to the hadronic and nuclear sector.

  14. The FLUKA Code: An Overview

    NASA Technical Reports Server (NTRS)

    Ballarini, F.; Battistoni, G.; Campanella, M.; Carboni, M.; Cerutti, F.; Empl, A.; Fasso, A.; Ferrari, A.; Gadioli, E.; Garzelli, M. V.; Lantz, M.; Liotta, M.; Mairani, A.; Mostacci, A.; Muraro, S.; Ottolenghi, A.; Pelliccioni, M.; Pinsky, L.; Ranft, J.; Roesler, S.; Sala, P. R.; Scannicchio, D.; Trovati, S.; Villari, R.; Wilson, T.

    2006-01-01

    FLUKA is a multipurpose Monte Carlo code which can transport a variety of particles over a wide energy range in complex geometries. The code is a joint project of INFN and CERN: part of its development is also supported by the University of Houston and NASA. FLUKA is successfully applied in several fields, including but not only, particle physics, cosmic ray physics, dosimetry, radioprotection, hadron therapy, space radiation, accelerator design and neutronics. The code is the standard tool used at CERN for dosimetry, radioprotection and beam-machine interaction studies. Here we give a glimpse into the code physics models with a particular emphasis to the hadronic and nuclear sector.

  15. Research on acceleration method of reactor physics based on FPGA platforms

    SciTech Connect

    Li, C.; Yu, G.; Wang, K.

    2013-07-01

    The physical designs of the new concept reactors which have complex structure, various materials and neutronic energy spectrum, have greatly improved the requirements to the calculation methods and the corresponding computing hardware. Along with the widely used parallel algorithm, heterogeneous platforms architecture has been introduced into numerical computations in reactor physics. Because of the natural parallel characteristics, the CPU-FPGA architecture is often used to accelerate numerical computation. This paper studies the application and features of this kind of heterogeneous platforms used in numerical calculation of reactor physics through practical examples. After the designed neutron diffusion module based on CPU-FPGA architecture achieves a 11.2 speed up factor, it is proved to be feasible to apply this kind of heterogeneous platform into reactor physics. (authors)

  16. Compendium of physical activities: an update of activity codes and MET intensities.

    PubMed

    Ainsworth, B E; Haskell, W L; Whitt, M C; Irwin, M L; Swartz, A M; Strath, S J; O'Brien, W L; Bassett, D R; Schmitz, K H; Emplaincourt, P O; Jacobs, D R; Leon, A S

    2000-09-01

    We provide an updated version of the Compendium of Physical Activities, a coding scheme that classifies specific physical activity (PA) by rate of energy expenditure. It was developed to enhance the comparability of results across studies using self-reports of PA. The Compendium coding scheme links a five-digit code that describes physical activities by major headings (e.g., occupation, transportation, etc.) and specific activities within each major heading with its intensity, defined as the ratio of work metabolic rate to a standard resting metabolic rate (MET). Energy expenditure in MET-minutes, MET-hours, kcal, or kcal per kilogram body weight can be estimated for specific activities by type or MET intensity. Additions to the Compendium were obtained from studies describing daily PA patterns of adults and studies measuring the energy cost of specific physical activities in field settings. The updated version includes two new major headings of volunteer and religious activities, extends the number of specific activities from 477 to 605, and provides updated MET intensity levels for selected activities.

  17. [Series: Medical Applications of the PHITS Code (2): Acceleration by Parallel Computing].

    PubMed

    Furuta, Takuya; Sato, Tatsuhiko

    2015-01-01

    Time-consuming Monte Carlo dose calculation becomes feasible owing to the development of computer technology. However, the recent development is due to emergence of the multi-core high performance computers. Therefore, parallel computing becomes a key to achieve good performance of software programs. A Monte Carlo simulation code PHITS contains two parallel computing functions, the distributed-memory parallelization using protocols of message passing interface (MPI) and the shared-memory parallelization using open multi-processing (OpenMP) directives. Users can choose the two functions according to their needs. This paper gives the explanation of the two functions with their advantages and disadvantages. Some test applications are also provided to show their performance using a typical multi-core high performance workstation.

  18. Graphics Processing Unit-Accelerated Code for Computing Second-Order Wiener Kernels and Spike-Triggered Covariance

    PubMed Central

    Mano, Omer

    2017-01-01

    Sensory neuroscience seeks to understand and predict how sensory neurons respond to stimuli. Nonlinear components of neural responses are frequently characterized by the second-order Wiener kernel and the closely-related spike-triggered covariance (STC). Recent advances in data acquisition have made it increasingly common and computationally intensive to compute second-order Wiener kernels/STC matrices. In order to speed up this sort of analysis, we developed a graphics processing unit (GPU)-accelerated module that computes the second-order Wiener kernel of a system’s response to a stimulus. The generated kernel can be easily transformed for use in standard STC analyses. Our code speeds up such analyses by factors of over 100 relative to current methods that utilize central processing units (CPUs). It works on any modern GPU and may be integrated into many data analysis workflows. This module accelerates data analysis so that more time can be spent exploring parameter space and interpreting data. PMID:28068420

  19. Physical implementation of a Majorana fermion surface code for fault-tolerant quantum computation

    NASA Astrophysics Data System (ADS)

    Vijay, Sagar; Fu, Liang

    2016-12-01

    We propose a physical realization of a commuting Hamiltonian of interacting Majorana fermions realizing Z 2 topological order, using an array of Josephson-coupled topological superconductor islands. The required multi-body interaction Hamiltonian is naturally generated by a combination of charging energy induced quantum phase-slips on the superconducting islands and electron tunneling between islands. Our setup improves on a recent proposal for implementing a Majorana fermion surface code (Vijay et al 2015 Phys. Rev. X 5 041038), a ‘hybrid’ approach to fault-tolerant quantum computation that combines (1) the engineering of a stabilizer Hamiltonian with a topologically ordered ground state with (2) projective stabilizer measurements to implement error correction and a universal set of logical gates. Our hybrid strategy has advantages over the traditional surface code architecture in error suppression and single-step stabilizer measurements, and is widely applicable to implementing stabilizer codes for quantum computation.

  20. Physics Based Model for Cryogenic Chilldown and Loading. Part IV: Code Structure

    NASA Technical Reports Server (NTRS)

    Luchinsky, D. G.; Smelyanskiy, V. N.; Brown, B.

    2014-01-01

    This is the fourth report in a series of technical reports that describe separated two-phase flow model application to the cryogenic loading operation. In this report we present the structure of the code. The code consists of five major modules: (1) geometry module; (2) solver; (3) material properties; (4) correlations; and finally (5) stability control module. The two key modules - solver and correlations - are further divided into a number of submodules. Most of the physics and knowledge databases related to the properties of cryogenic two-phase flow are included into the cryogenic correlations module. The functional form of those correlations is not well established and is a subject of extensive research. Multiple parametric forms for various correlations are currently available. Some of them are included into correlations module as will be described in details in a separate technical report. Here we describe the overall structure of the code and focus on the details of the solver and stability control modules.

  1. Experimental Mapping and Benchmarking of Magnetic Field Codes on the LHD Ion Accelerator

    SciTech Connect

    Chitarin, G.; Agostinetti, P.; Gallo, A.; Marconato, N.; Serianni, G.; Nakano, H.; Takeiri, Y.; Tsumori, K.

    2011-09-26

    For the validation of the numerical models used for the design of the Neutral Beam Test Facility for ITER in Padua [1], an experimental benchmark against a full-size device has been sought. The LHD BL2 injector [2] has been chosen as a first benchmark, because the BL2 Negative Ion Source and Beam Accelerator are geometrically similar to SPIDER, even though BL2 does not include current bars and ferromagnetic materials. A comprehensive 3D magnetic field model of the LHD BL2 device has been developed based on the same assumptions used for SPIDER. In parallel, a detailed experimental magnetic map of the BL2 device has been obtained using a suitably designed 3D adjustable structure for the fine positioning of the magnetic sensors inside 27 of the 770 beamlet apertures. The calculated values have been compared to the experimental data. The work has confirmed the quality of the numerical model, and has also provided useful information on the magnetic non-uniformities due to the edge effects and to the tolerance on permanent magnet remanence.

  2. Experimental Mapping and Benchmarking of Magnetic Field Codes on the LHD Ion Accelerator

    NASA Astrophysics Data System (ADS)

    Chitarin, G.; Agostinetti, P.; Gallo, A.; Marconato, N.; Nakano, H.; Serianni, G.; Takeiri, Y.; Tsumori, K.

    2011-09-01

    For the validation of the numerical models used for the design of the Neutral Beam Test Facility for ITER in Padua [1], an experimental benchmark against a full-size device has been sought. The LHD BL2 injector [2] has been chosen as a first benchmark, because the BL2 Negative Ion Source and Beam Accelerator are geometrically similar to SPIDER, even though BL2 does not include current bars and ferromagnetic materials. A comprehensive 3D magnetic field model of the LHD BL2 device has been developed based on the same assumptions used for SPIDER. In parallel, a detailed experimental magnetic map of the BL2 device has been obtained using a suitably designed 3D adjustable structure for the fine positioning of the magnetic sensors inside 27 of the 770 beamlet apertures. The calculated values have been compared to the experimental data. The work has confirmed the quality of the numerical model, and has also provided useful information on the magnetic non-uniformities due to the edge effects and to the tolerance on permanent magnet remanence.

  3. Evaluation of the HTR-10 Reactor as a Benchmark for Physics Code QA

    SciTech Connect

    William K. Terry; Soon Sam Kim; Leland M. Montierth; Joshua J. Cogliati; Abderrafi M. Ougouag

    2006-09-01

    The HTR-10 is a small (10 MWt) pebble-bed research reactor intended to develop pebble-bed reactor (PBR) technology in China. It will be used to test and develop fuel, verify PBR safety features, demonstrate combined electricity production and co-generation of heat, and provide experience in PBR design, operation, and construction. As the only currently operating PBR in the world, the HTR-10 can provide data of great interest to everyone involved in PBR technology. In particular, if it yields data of sufficient quality, it can be used as a benchmark for assessing the accuracy of computer codes proposed for use in PBR analysis. This paper summarizes the evaluation for the International Reactor Physics Experiment Evaluation Project (IRPhEP) of data obtained in measurements of the HTR-10’s initial criticality experiment for use as benchmarks for reactor physics codes.

  4. Plasma turbulence, suprathermal ion dynamics and code validation on the basic plasma physics device TORPEX

    NASA Astrophysics Data System (ADS)

    Furno, I.; Avino, F.; Bovet, A.; Diallo, A.; Fasoli, A.; Gustafson, K.; Iraji, D.; Labit, B.; Loizu, J.; Müller, S. H.; Plyushchev, G.; Podestà, M.; Poli, F. M.; Ricci, P.; Theiler, C.

    2015-06-01

    The TORPEX basic plasma physics device at the Center for Plasma Physics Research (CRPP) in Lausanne, Switzerland is described. In TORPEX, simple magnetized toroidal configurations, a paradigm for the tokamak scrape-off layer (SOL), as well as more complex magnetic geometries of direct relevance for fusion are produced. Plasmas of different gases are created and sustained by microwaves in the electron-cyclotron (EC) frequency range. Full diagnostic access allows for a complete characterization of plasma fluctuations and wave fields throughout the entire plasma volume, opening new avenues to validate numerical codes. We detail recent advances in the understanding of basic aspects of plasma turbulence, including its development from linearly unstable electrostatic modes, the formation of filamentary structures, or blobs, and its influence on the transport of energy, plasma bulk and suprathermal ions. We present a methodology for the validation of plasma turbulence codes, which focuses on quantitative assessment of the agreement between numerical simulations and TORPEX experimental data.

  5. User`s guide and physics manual for the SCATPlus circuit code

    SciTech Connect

    Yapuncich, M.L.; Deninger, W.J.; Gribble, R.F.

    1994-05-09

    ScatPlus is a user friendly circuit code and an expandable library of circuit models for electrical components and devices; it can be used to predict the transient behavior in electric circuits. The heart of ScatPlus is the transient circuit solver SCAT written in 1986 by R.F. Gribble. This manual includes system requirements, physics manual, ScatPlus component library, tutorial, ScatPlus screen, menus and toolbar, ScatPlus tool bar, procedures.

  6. Signal of Acceleration and Physical Mechanism of Water Cycle in Xinjiang, China

    PubMed Central

    Feng, Guo-Lin; Wu, Yong-Ping

    2016-01-01

    Global warming accelerates water cycle with features of regional difference. However, little is known about the physical mechanism behind the phenomenon. To reveal the links between water cycle and climatic environment, we analyzed the changes of water cycle elements and their relationships with climatic and environmental factors. We found that when global warming was significant during the period of 1986-2003, the precipitation in Tarim mountains as well as Xinjiang increased rapidly except for Tarim plains, which indicated that there existed a signal of acceleration for water cycle in Xinjiang. The speed of water cycle is mainly affected by altitude, latitude, longitude, slope direction, and the most fundamental element is temperature. Moreover, according to Clausius-Kela Bai Lung relation, we found that the climate change induced the increase of temperature and accelerated the local water cycle only for the wet places. Our results provide a possible physical mechanisms of water cycle and thus well link the climate change to water circulation. PMID:27907078

  7. Accelerated Evolution of Schistosome Genes Coding for Proteins Located at the Host–Parasite Interface

    PubMed Central

    Philippsen, Gisele S.; Wilson, R. Alan; DeMarco, Ricardo

    2015-01-01

    Study of proteins located at the host–parasite interface in schistosomes might provide clues about the mechanisms utilized by the parasite to escape the host immune system attack. Micro-exon gene (MEG) protein products and venom allergen-like (VAL) proteins have been shown to be present in schistosome secretions or associated with glands, which led to the hypothesis that they are important components in the molecular interaction of the parasite with the host. Phylogenetic and structural analysis of genes and their transcripts in these two classes shows that recent species-specific expansion of gene number for these families occurred separately in three different species of schistosomes. Enrichment of transposable elements in MEG and VAL genes in Schistosoma mansoni provides a credible mechanism for preferential expansion of gene numbers for these families. Analysis of the ratio between synonymous and nonsynonymous substitution rates (dN/dS) in the comparison between schistosome orthologs for the two classes of genes reveals significantly higher values when compared with a set of a control genes coding for secreted proteins, and for proteins previously localized in the tegument. Additional analyses of paralog genes indicate that exposure of the protein to the definitive host immune system is a determining factor leading to the higher than usual dN/dS values in those genes. The observation that two genes encoding S. mansoni vaccine candidate proteins, known to be exposed at the parasite surface, also display similar evolutionary dynamics suggests a broad response of the parasite to evolutionary pressure imposed by the definitive host immune system. PMID:25567667

  8. Prediction of reliability on thermoelectric module through accelerated life test and Physics-of-failure

    NASA Astrophysics Data System (ADS)

    Choi, Hyoung-Seuk; Seo, Won-Seon; Choi, Duck-Kyun

    2011-09-01

    Thermoelectric cooling module (TEM) which is electric device has a mechanical stress because of temperature gradient in itself. It means that structure of TEM is vulnerable in an aspect of reliability but research on reliability of TEM was not performed a lot. Recently, the more the utilization of thermoelectric cooling devices grows, the more the needs for life prediction and improvement are increasing. In this paper, we investigated life distribution, shape parameter of the TEM through accelerated life test (ALT). And we discussed about how to enhance life of TEM through the Physics-of-failure. Experimental results of ALT showed that the thermoelectric cooling module follows the Weibull distribution, shape parameter of which is 3.6. The acceleration model is coffin Coffin-Manson and material constant is 1.8.

  9. VINE-A NUMERICAL CODE FOR SIMULATING ASTROPHYSICAL SYSTEMS USING PARTICLES. I. DESCRIPTION OF THE PHYSICS AND THE NUMERICAL METHODS

    SciTech Connect

    Wetzstein, M.; Nelson, Andrew F.; Naab, T.; Burkert, A.

    2009-10-01

    We present a numerical code for simulating the evolution of astrophysical systems using particles to represent the underlying fluid flow. The code is written in Fortran 95 and is designed to be versatile, flexible, and extensible, with modular options that can be selected either at the time the code is compiled or at run time through a text input file. We include a number of general purpose modules describing a variety of physical processes commonly required in the astrophysical community and we expect that the effort required to integrate additional or alternate modules into the code will be small. In its simplest form the code can evolve the dynamical trajectories of a set of particles in two or three dimensions using a module which implements either a Leapfrog or Runge-Kutta-Fehlberg integrator, selected by the user at compile time. The user may choose to allow the integrator to evolve the system using individual time steps for each particle or with a single, global time step for all. Particles may interact gravitationally as N-body particles, and all or any subset may also interact hydrodynamically, using the smoothed particle hydrodynamic (SPH) method by selecting the SPH module. A third particle species can be included with a module to model massive point particles which may accrete nearby SPH or N-body particles. Such particles may be used to model, e.g., stars in a molecular cloud. Free boundary conditions are implemented by default, and a module may be selected to include periodic boundary conditions. We use a binary 'Press' tree to organize particles for rapid access in gravity and SPH calculations. Modules implementing an interface with special purpose 'GRAPE' hardware may also be selected to accelerate the gravity calculations. If available, forces obtained from the GRAPE coprocessors may be transparently substituted for those obtained from the tree, or both tree and GRAPE may be used as a combination GRAPE/tree code. The code may be run without

  10. Vine—A Numerical Code for Simulating Astrophysical Systems Using Particles. I. Description of the Physics and the Numerical Methods

    NASA Astrophysics Data System (ADS)

    Wetzstein, M.; Nelson, Andrew F.; Naab, T.; Burkert, A.

    2009-10-01

    We present a numerical code for simulating the evolution of astrophysical systems using particles to represent the underlying fluid flow. The code is written in Fortran 95 and is designed to be versatile, flexible, and extensible, with modular options that can be selected either at the time the code is compiled or at run time through a text input file. We include a number of general purpose modules describing a variety of physical processes commonly required in the astrophysical community and we expect that the effort required to integrate additional or alternate modules into the code will be small. In its simplest form the code can evolve the dynamical trajectories of a set of particles in two or three dimensions using a module which implements either a Leapfrog or Runge-Kutta-Fehlberg integrator, selected by the user at compile time. The user may choose to allow the integrator to evolve the system using individual time steps for each particle or with a single, global time step for all. Particles may interact gravitationally as N-body particles, and all or any subset may also interact hydrodynamically, using the smoothed particle hydrodynamic (SPH) method by selecting the SPH module. A third particle species can be included with a module to model massive point particles which may accrete nearby SPH or N-body particles. Such particles may be used to model, e.g., stars in a molecular cloud. Free boundary conditions are implemented by default, and a module may be selected to include periodic boundary conditions. We use a binary "Press" tree to organize particles for rapid access in gravity and SPH calculations. Modules implementing an interface with special purpose "GRAPE" hardware may also be selected to accelerate the gravity calculations. If available, forces obtained from the GRAPE coprocessors may be transparently substituted for those obtained from the tree, or both tree and GRAPE may be used as a combination GRAPE/tree code. The code may be run without

  11. Towards Extreme Field Physics: Relativistic Optics and Particle Acceleration in the Transparent-Overdense Regime

    NASA Astrophysics Data System (ADS)

    Hegelich, B. Manuel

    2011-10-01

    A steady increase of on-target laser intensity with also increasing pulse contrast is leading to light-matter interactions of extreme laser fields with matter in new physics regimes which in turn enable a host of applications. A first example is the realization of interactions in the transperent-overdense regime (TOR), which is reached by interacting a highly relativistic (a0 >10), ultra high contrast laser pulse [1] with a solid density target, turning it transparent to the laser by the relativistic mass increase of the electrons. Thus, the interactions becomes volumetric, increasing the energy coupling from laser to plasma, facilitating a range of effects, including relativistic optics and pulse shaping, mono-energetic electron acceleration [3], highly efficient ion acceleration in the break-out afterburner regime [4], and the generation of relativistic and forward directed surface harmonics. Experiments at the LANL 130TW Trident laser facility successfully reached the TOR, and show relativistic pulse shaping beyond the Fourier limit, the acceleration of mono-energetic ~40 MeV electron bunches from solid targets, forward directed coherent relativistic high harmonic generation >1 keV Break-Out Afterburner (BOA) ion acceleration of Carbon to >1 GeV and Protons to >100 MeV. Carbon ions were accelerated with a conversion efficiency of >10% for ions >20 MeV and monoenergetic carbon ions with an energy spread of <20%, have been accelerated at up to ~500 MeV, demonstrating 3 out of 4 for key requirements for ion fast ignition. The shown results now approach or exceed the limits set by many applications from ICF diagnostics over ion fast ignition to medical physics. Furthermore, TOR targets traverse a wide range of HEDP parameter space during the interaction ranging from WDM conditions (e.g. brown dwarfs) to energy densities of ~1011 J/cm3 at peak, then dropping back to the underdense but extremely hot parameter range of gamma-ray bursts. Whereas today this regime can

  12. The Dresden Felsenkeller shallow-underground accelerator laboratory for nuclear astrophysics - Status and first physics program

    SciTech Connect

    Ilgner, Ch.

    2015-07-01

    Favored by the low background in underground laboratories, low-background accelerator-based experiments are an important tool to study nuclear reactions involving stable charged particles. This technique has been used for many years with great success at the 0.4 MV LUNA accelerator in the Gran Sasso laboratory in Italy, protected from cosmic rays by 1400 m of rock. However, the nuclear reactions of helium and carbon burning and the neutron source reactions for the astrophysical s-process require higher beam energies than those available at LUNA. Also the study of solar fusion reactions necessitates new data at higher energies. As a result, in the present NuPECC long range plan for nuclear physics in Europe, the installation of one or more higher-energy underground accelerators is strongly recommended. An intercomparison exercise using the same High-Purity Ge detector at several sites has shown that, with a combination of 45 m rock overburden, as can be found in the Felsenkeller underground site in Dresden, and an active veto against the remaining muon flux, in a typical nuclear astrophysics setup a background level can be achieved that is similar to the deep underground scenario as in the Gran- Sasso underground laboratory, for instance. Recently, a muon background study and geodetic measurements were carried out by the REGARD group. It was estimated that the rock overburden at the place of the future ion accelerator is equivalent to 130 m of water. The maximum muon flux measured was 2.5 m{sup -2} sr{sup -1} s{sup -1}, in the direction of the tunnel entrance. Based on this finding, a used 5 MV pelletron tandem accelerator with 250 μA up-charge current and external sputter ion source has been obtained and transported to Dresden. Work on an additional radio-frequency ion source on the high voltage terminal is in progress and far advanced. The installation of the accelerator in the Felsenkeller is expected for the near future. The status of the project and the

  13. Report of the HEPAP Subpanel on Major Detectors in Non-Accelerator Particle Physics

    NASA Astrophysics Data System (ADS)

    1989-05-01

    The subpanel on Major Detectors in Non-Accelerator Particle Physics was formed in February 1989 as the result of a letter from Robert Hunter, Director, Office of Energy Research, to Francis Low, Chairman of HEPAP. A copy of the letter is included in the Appendix to this report. The letter referred to the previous report of HEPAP Subpanel on High Energy Gamma Ray and Neutrino Astronomy which had found that several groups of scientists were working on promising new ideas and proposals in non-accelerator high energy physics and astrophysics; this report recommended that panel be formed to evaluate large projects in these areas of science when specific proposals were received by the funding agencies. In concurring with the recommendation, the request to establish this new Subpanel included the following specific charge: Within the context of changing world wide high energy physics activities and opportunities, review as necessary and evaluate the following major research proposals which have been submitted to the Department of Energy and/or to the National Science foundation: DUMAND II, GRANDE, and the Fly's Eye Upgrade.

  14. Report of the HEPAP subpanel on major detectors in non-accelerator particle physics

    SciTech Connect

    Not Available

    1989-05-01

    The subpanel on Major Detectors in Non-Accelerator Particle Physics was formed in February 1989 as the result of a letter from Robert Hunter, Director, Office of Energy Research, to Francis Low, Chairman of HEPAP. A copy of the letter is included in the Appendix to this report. The letter referred to the previous report of HEPAP Subpanel on High Energy Gamma Ray and Neutrino Astronomy which had found that several groups of scientists were working on promising new ideas and proposals in non-accelerator high energy physics and astrophysics; this report recommended that panel be formed to evaluate large projects in these areas of science when specific proposals were received by the funding agencies. In concurring with the recommendation, the request to establish this new Subpanel included the following specific charge: Within the context of changing world wide high energy physics activities and opportunities, review as necessary and evaluate the following major research proposals which have been submitted to the Department of Energy and/or to the National Science foundation: DUMAND II, GRANDE, and the Fly's Eye Upgrade.

  15. Dosimetric Characteristics of 6 MV Modified Beams by Physical Wedges of a Siemens Linear Accelerator.

    PubMed

    Zabihzadeh, Mansour; Birgani, Mohammad Javad Tahmasebi; Hoseini-Ghahfarokhi, Mojtaba; Arvandi, Sholeh; Hoseini, Seyed Mohammad; Fadaei, Mahbube

    2016-01-01

    Physical wedges still can be used as missing tissue compensators or filters to alter the shape of isodose curves in a target volume to reach an optimal radiotherapy plan without creating a hotspot. The aim of this study was to investigate the dosimetric properties of physical wedges filters such as off-axis photon fluence, photon spectrum, output factor and half value layer. The photon beam quality of a 6 MV Primus Siemens modified by 150 and 450 physical wedges was studied with BEAMnrc Monte Carlo (MC) code. The calculated present depth dose and dose profile curves for open and wedged photon beam were in good agreement with the measurements. Increase of wedge angle increased the beam hardening and this effect was more pronounced at the heal region. Using such an accurate MC model to determine of wedge factors and implementation of it as a calculation algorithm in the future treatment planning systems is recommended.

  16. Topics in radiation at accelerators: Radiation physics for personnel and environmental protection

    SciTech Connect

    Cossairt, J.D.

    1993-11-01

    This report discusses the following topics: Composition of Accelerator Radiation Fields; Shielding of Electrons and Photons at Accelerators; Shielding of Hadrons at Accelerators; Low Energy Prompt Radiation Phenomena; Induced Radioactivity at Accelerators; Topics in Radiation Protection Instrumentation at Accelerators; and Accelerator Radiation Protection Program Elements.

  17. High-Fidelity Lattice Physics Capabilities of the SCALE Code System Using TRITON

    SciTech Connect

    DeHart, Mark D

    2007-01-01

    Increasing complexity in reactor designs suggests a need to reexamine of methods applied in spent-fuel characterization. The ability to accurately predict the nuclide composition of depleted reactor fuel is important in a wide variety of applications. These applications include, but are not limited to, the design, licensing, and operation of commercial/research reactors and spent-fuel transport/storage systems. New complex design projects such as space reactors and Generation IV power reactors also require calculational methods that provide accurate prediction of the isotopic inventory. New high-fidelity physics methods will be required to better understand the physics associated with both evolutionary and revolutionary reactor concepts as they depart from traditional and well-understood light-water reactor designs. The TRITON sequence of the SCALE code system provides a powerful, robust, and rigorous approach for reactor physics analysis. This paper provides a detailed description of TRITON in terms of its key components used in reactor calculations.

  18. Using the FLUKA Monte Carlo Code to Simulate the Interactions of Ionizing Radiation with Matter to Assist and Aid Our Understanding of Ground Based Accelerator Testing, Space Hardware Design, and Secondary Space Radiation Environments

    NASA Technical Reports Server (NTRS)

    Reddell, Brandon

    2015-01-01

    Designing hardware to operate in the space radiation environment is a very difficult and costly activity. Ground based particle accelerators can be used to test for exposure to the radiation environment, one species at a time, however, the actual space environment cannot be duplicated because of the range of energies and isotropic nature of space radiation. The FLUKA Monte Carlo code is an integrated physics package based at CERN that has been under development for the last 40+ years and includes the most up-to-date fundamental physics theory and particle physics data. This work presents an overview of FLUKA and how it has been used in conjunction with ground based radiation testing for NASA and improve our understanding of secondary particle environments resulting from the interaction of space radiation with matter.

  19. Physical Mechanism of the Transverse Instability in Radiation Pressure Ion Acceleration

    NASA Astrophysics Data System (ADS)

    Wan, Y.; Pai, C.-H.; Zhang, C. J.; Li, F.; Wu, Y. P.; Hua, J. F.; Lu, W.; Gu, Y. Q.; Silva, L. O.; Joshi, C.; Mori, W. B.

    2016-12-01

    The transverse stability of the target is crucial for obtaining high quality ion beams using the laser radiation pressure acceleration (RPA) mechanism. In this Letter, a theoretical model and supporting two-dimensional (2D) particle-in-cell (PIC) simulations are presented to clarify the physical mechanism of the transverse instability observed in the RPA process. It is shown that the density ripples of the target foil are mainly induced by the coupling between the transverse oscillating electrons and the quasistatic ions, a mechanism similar to the oscillating two stream instability in the inertial confinement fusion research. The predictions of the mode structure and the growth rates from the theory agree well with the results obtained from the PIC simulations in various regimes, indicating the model contains the essence of the underlying physics of the transverse breakup of the target.

  20. Benchmarking of epithermal methods in the lattice-physics code EPRI-CELL

    NASA Astrophysics Data System (ADS)

    Williams, M. L.; Wright, R. Q.; Barhen, J.; Rothenstein, W.; Toney, B.

    The epithermal cross section shielding methods used in the lattice physics code EPRI-CELL (E-C) were extensively studied to determine its major approximations and to examine the sensitivity of computed results to these approximations. Several improvements in the original methodology resulted. These include: treatment of the external moderator source with intermediate resonance (IR) theory, development of a new Dancoff factor expression to account for clad interactions, development of a new method for treating resonance interference, and application of a generalized least squares methods to compute best estimate values for the Bell factor and group dependent IR parameters. The modified E-C code with its new ENDF/B-V cross section library is tested for several numerical benchmark problems.

  1. Physics and Novel Schemes of Laser Radiation Pressure Acceleration for Quasi-monoenergetic Proton Generation

    SciTech Connect

    Liu, Chuan S.; Shao, Xi

    2016-06-14

    The main objective of our work is to provide theoretical basis and modeling support for the design and experimental setup of compact laser proton accelerator to produce high quality proton beams tunable with energy from 50 to 250 MeV using short pulse sub-petawatt laser. We performed theoretical and computational studies of energy scaling and Raleigh--Taylor instability development in laser radiation pressure acceleration (RPA) and developed novel RPA-based schemes to remedy/suppress instabilities for high-quality quasimonoenergetic proton beam generation as we proposed. During the project period, we published nine peer-reviewed journal papers and made twenty conference presentations including six invited talks on our work. The project supported one graduate student who received his PhD degree in physics in 2013 and supported two post-doctoral associates. We also mentored three high school students and one undergraduate student of physics major by inspiring their interests and having them involved in the project.

  2. Tsallis entropy and complexity theory in the understanding of physics of precursory accelerating seismicity.

    NASA Astrophysics Data System (ADS)

    Vallianatos, Filippos; Chatzopoulos, George

    2014-05-01

    Strong observational indications support the hypothesis that many large earthquakes are preceded by accelerating seismic release rates which described by a power law time to failure relation. In the present work, a unified theoretical framework is discussed based on the ideas of non-extensive statistical physics along with fundamental principles of physics such as the energy conservation in a faulted crustal volume undergoing stress loading. We derive the time-to-failure power-law of: a) cumulative number of earthquakes, b) cumulative Benioff strain and c) cumulative energy released in a fault system that obeys a hierarchical distribution law extracted from Tsallis entropy. Considering the analytic conditions near the time of failure, we derive from first principles the time-to-failure power-law and show that a common critical exponent m(q) exists, which is a function of the non-extensive entropic parameter q. We conclude that the cumulative precursory parameters are function of the energy supplied to the system and the size of the precursory volume. In addition the q-exponential distribution which describes the fault system is a crucial factor on the appearance of power-law acceleration in the seismicity. Our results based on Tsallis entropy and the energy conservation gives a new view on the empirical laws derived by other researchers. Examples and applications of this technique to observations of accelerating seismicity will also be presented and discussed. This work was implemented through the project IMPACT-ARC in the framework of action "ARCHIMEDES III-Support of Research Teams at TEI of Crete" (MIS380353) of the Operational Program "Education and Lifelong Learning" and is co-financed by the European Union (European Social Fund) and Greek national funds

  3. Physical-Layer Network Coding for VPN in TDM-PON

    NASA Astrophysics Data System (ADS)

    Wang, Qike; Tse, Kam-Hon; Chen, Lian-Kuan; Liew, Soung-Chang

    2012-12-01

    We experimentally demonstrate a novel optical physical-layer network coding (PNC) scheme over time-division multiplexing (TDM) passive optical network (PON). Full-duplex error-free communications between optical network units (ONUs) at 2.5 Gb/s are shown for all-optical virtual private network (VPN) applications. Compared to the conventional half-duplex communications set-up, our scheme can increase the capacity by 100% with power penalty smaller than 3 dB. Synchronization of two ONUs is not required for the proposed VPN scheme

  4. Theory and application of the RAZOR two-dimensional continuous energy lattice physics code

    SciTech Connect

    Zerkle, M.L.; Abu-Shumays, I.K.; Ott, M.W.; Winwood, J.P.

    1997-04-01

    The theory and application of the RAZOR two-dimensional, continuous energy lattice physics code are discussed. RAZOR solves the continuous energy neutron transport equation in one- and two-dimensional geometries, and calculates equivalent few-group diffusion theory constants that rigorously account for spatial and spectral self-shielding effects. A dual energy resolution slowing down algorithm is used to reduce computer memory and disk storage requirements for the slowing down calculation. Results are presented for a 2D BWR pin cell depletion benchmark problem.

  5. Parallelization issues of a code for physically-based simulation of fabrics

    NASA Astrophysics Data System (ADS)

    Romero, Sergio; Gutiérrez, Eladio; Romero, Luis F.; Plata, Oscar; Zapata, Emilio L.

    2004-10-01

    The simulation of fabrics, clothes, and flexible materials is an essential topic in computer animation of realistic virtual humans and dynamic sceneries. New emerging technologies, as interactive digital TV and multimedia products, make necessary the development of powerful tools to perform real-time simulations. Parallelism is one of such tools. When analyzing computationally fabric simulations we found these codes belonging to the complex class of irregular applications. Frequently this kind of codes includes reduction operations in their core, so that an important fraction of the computational time is spent on such operations. In fabric simulators these operations appear when evaluating forces, giving rise to the equation system to be solved. For this reason, this paper discusses only this phase of the simulation. This paper analyzes and evaluates different irregular reduction parallelization techniques on ccNUMA shared memory machines, applied to a real, physically-based, fabric simulator we have developed. Several issues are taken into account in order to achieve high code performance, as exploitation of data access locality and parallelism, as well as careful use of memory resources (memory overhead). In this paper we use the concept of data affinity to develop various efficient algorithms for reduction parallelization exploiting data locality.

  6. Technical Challenges and Scientific Payoffs of Muon BeamAccelerators for Particle Physics

    SciTech Connect

    Zisman, Michael S.

    2007-09-25

    Historically, progress in particle physics has largely beendetermined by development of more capable particle accelerators. Thistrend continues today with the recent advent of high-luminosityelectron-positron colliders at KEK and SLAC operating as "B factories,"the imminent commissioning of the Large Hadron Collider at CERN, and theworldwide development effort toward the International Linear Collider.Looking to the future, one of the most promising approaches is thedevelopment of muon-beam accelerators. Such machines have very highscientific potential, and would substantially advance thestate-of-the-art in accelerator design. A 20-50 GeV muon storage ringcould serve as a copious source of well-characterized electron neutrinosor antineutrinos (a Neutrino Factory), providing beams aimed at detectorslocated 3000-7500 km from the ring. Such long baseline experiments areexpected to be able to observe and characterize the phenomenon ofcharge-conjugation-parity (CP) violation in the lepton sector, and thusprovide an answer to one of the most fundamental questions in science,namely, why the matter-dominated universe in which we reside exists atall. By accelerating muons to even higher energies of several TeV, we canenvision a Muon Collider. In contrast with composite particles likeprotons, muons are point particles. This means that the full collisionenergy is available to create new particles. A Muon Collider has roughlyten times the energy reach of a proton collider at the same collisionenergy, and has a much smaller footprint. Indeed, an energy frontier MuonCollider could fit on the site of an existing laboratory, such asFermilab or BNL. The challenges of muon-beam accelerators are related tothe facts that i) muons are produced as a tertiary beam, with very large6D phase space, and ii) muons are unstable, with a lifetime at rest ofonly 2 microseconds. How these challenges are accommodated in theaccelerator design will be described. Both a Neutrino Factory and a Muon

  7. A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research.

    PubMed

    Mocker, Anna; Bugiel, Sebastian; Auer, Siegfried; Baust, Günter; Colette, Andrew; Drake, Keith; Fiege, Katherina; Grün, Eberhard; Heckmann, Frieder; Helfert, Stefan; Hillier, Jonathan; Kempf, Sascha; Matt, Günter; Mellert, Tobias; Munsat, Tobin; Otto, Katharina; Postberg, Frank; Röser, Hans-Peter; Shu, Anthony; Sternovsky, Zoltán; Srama, Ralf

    2011-09-01

    Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut für Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s(-1). Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s(-1) and with diameters of between 0.05 μm and 5 μm. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and charges, and

  8. A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research

    SciTech Connect

    Mocker, Anna; Bugiel, Sebastian; Srama, Ralf; Auer, Siegfried; Baust, Guenter; Matt, Guenter; Otto, Katharina; Colette, Andrew; Drake, Keith; Kempf, Sascha; Munsat, Tobin; Shu, Anthony; Sternovsky, Zoltan; Fiege, Katherina; Postberg, Frank; Gruen, Eberhard; Heckmann, Frieder; Helfert, Stefan; Hillier, Jonathan; Mellert, Tobias; and others

    2011-09-15

    Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut fuer Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s{sup -1}. Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s{sup -1} and with diameters of between 0.05 {mu}m and 5 {mu}m. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and

  9. Additions and Improvements to the FLASH Code for Simulating High Energy Density Physics Experiments

    NASA Astrophysics Data System (ADS)

    Lamb, D. Q.; Daley, C.; Dubey, A.; Fatenejad, M.; Flocke, N.; Graziani, C.; Lee, D.; Tzeferacos, P.; Weide, K.

    2015-11-01

    FLASH is an open source, finite-volume Eulerian, spatially adaptive radiation hydrodynamics and magnetohydrodynamics code that incorporates capabilities for a broad range of physical processes, performs well on a wide range of computer architectures, and has a broad user base. Extensive capabilities have been added to FLASH to make it an open toolset for the academic high energy density physics (HEDP) community. We summarize these capabilities, with particular emphasis on recent additions and improvements. These include advancements in the optical ray tracing laser package, with methods such as bi-cubic 2D and tri-cubic 3D interpolation of electron number density, adaptive stepping and 2nd-, 3rd-, and 4th-order Runge-Kutta integration methods. Moreover, we showcase the simulated magnetic field diagnostic capabilities of the code, including induction coils, Faraday rotation, and proton radiography. We also describe several collaborations with the National Laboratories and the academic community in which FLASH has been used to simulate HEDP experiments. This work was supported in part at the University of Chicago by the DOE NNSA ASC through the Argonne Institute for Computing in Science under field work proposal 57789; and the NSF under grant PHY-0903997.

  10. A Chaos MIMO Transmission Scheme for Channel Coding and Physical-Layer Security

    NASA Astrophysics Data System (ADS)

    Okamoto, Eiji

    In recent wireless communication systems, security is ensured mainly in the upper-layer techniques such as a password or a cryptography processing. However, security needs not be restricted to the upper-layer and the addition of physical-layer security also would yield a much more robust system. Therefore, in this paper, we exploit chaos communication and propose a chaos multiple-input multiple-output (MIMO) transmission scheme which achieves physical-layer security and additional channel-coding gain. A chaotic modulation symbol is multiplied to the data to be transmitted at each MIMO antenna to exploit the MIMO antenna diversity, and at the receiver, the joint MIMO detection and chaos decoding is done by maximum likelihood decoding (MLD). The conventional chaos modulation suffers from bit error rate (BER) performance degradation, while the coding gain is obtained in the proposed scheme by the chaos modulation in MIMO. We evaluate the performances of the proposed scheme by an analysis and computer simulations.

  11. The physics and technology basis entering European system code studies for DEMO

    NASA Astrophysics Data System (ADS)

    Wenninger, R.; Kembleton, R.; Bachmann, C.; Biel, W.; Bolzonella, T.; Ciattaglia, S.; Cismondi, F.; Coleman, M.; Donné, A. J. H.; Eich, T.; Fable, E.; Federici, G.; Franke, T.; Lux, H.; Maviglia, F.; Meszaros, B.; Pütterich, T.; Saarelma, S.; Snickers, A.; Villone, F.; Vincenzi, P.; Wolff, D.; Zohm, H.

    2017-01-01

    A large scale program to develop a conceptual design for a demonstration fusion power plant (DEMO) has been initiated in Europe. Central elements are the baseline design points, which are developed by system codes. The assessment of the credibility of these design points is often hampered by missing information. The main physics and technology content of the central European system codes have been published (Kovari et al 2014 Fusion Eng. Des. 89 3054-69, 2016 Fusion Eng. Des. 104 9-20, Reux et al 2015 Nucl. Fusion 55 073011). In addition, this publication discusses key input parameters for the pulsed and conservative design option \\tt{EU DEMO1 2015} and provides justifications for the parameter choices. In this context several DEMO physics gaps are identified, which need to be addressed in the future to reduce the uncertainty in predicting the performance of the device. Also the sensitivities of net electric power and pulse duration to variations of the input parameters are investigated. The most extreme sensitivity is found for the elongation ( Δ {κ95}=10 % corresponds to Δ {{P}\\text{el,\\text{net}}}=125 % ).

  12. Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor.

    PubMed

    Singh, M J; De Esch, H P L

    2010-01-01

    This paper describes the physics design of a 100 keV, 60 A H(-) accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated.

  13. Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor

    NASA Astrophysics Data System (ADS)

    Singh, M. J.; De Esch, H. P. L.

    2010-01-01

    This paper describes the physics design of a 100 keV, 60 A H- accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated.

  14. GPU-based acceleration of free energy calculations in solid state physics

    NASA Astrophysics Data System (ADS)

    Januszewski, Michał; Ptok, Andrzej; Crivelli, Dawid; Gardas, Bartłomiej

    2015-07-01

    Obtaining a thermodynamically accurate phase diagram through numerical calculations is a computationally expensive problem that is crucially important to understanding the complex phenomena of solid state physics, such as superconductivity. In this work we show how this type of analysis can be significantly accelerated through the use of modern GPUs. We illustrate this with a concrete example of free energy calculation in multi-band iron-based superconductors, known to exhibit a superconducting state with oscillating order parameter (OP). Our approach can also be used for classical BCS-type superconductors. With a customized algorithm and compiler tuning we are able to achieve a 19×speedup compared to the CPU (119×compared to a single CPU core), reducing calculation time from minutes to mere seconds, enabling the analysis of larger systems and the elimination of finite size effects.

  15. Beam Polarization at the ILC: the Physics Impact and the Accelerator Solutions

    SciTech Connect

    Aurand, B.; Bailey, I.; Bartels, C.; Brachmann, A.; Clarke, J.; Hartin, A.; Hauptman, J.; Helebrant, C.; Hesselbach, S.; Kafer, D.; List, J.; Lorenzon, W.; Marchesini, I.; Monig, Klaus; Moffeit, K.C.; Moortgat-Pick, G.; Riemann, S.; Schalicke, A.; Schuler, P.; Starovoitov, P.; Ushakov, A.; /DESY /DESY, Zeuthen /Bonn U. /SLAC

    2011-11-23

    In this contribution accelerator solutions for polarized beams and their impact on physics measurements are discussed. Focus are physics requirements for precision polarimetry near the interaction point and their realization with polarized sources. Based on the ILC baseline programme as described in the Reference Design Report (RDR), recent developments are discussed and evaluated taking into account physics runs at beam energies between 100 GeV and 250 GeV, as well as calibration runs on the Z-pole and options as the 1TeV upgrade and GigaZ. The studies, talks and discussions presented at this conference demonstrated that beam polarization and its measurement are crucial for the physics success of any future linear collider. To achieve the required precision it is absolutely decisive to employ multiple devices for testing and controlling the systematic uncertainties of each polarimeter. The polarimetry methods for the ILC are complementary: with the upstream polarimeter the measurements are performed in a clean environment, they are fast and allow to monitor time-dependent variations of polarization. The polarimeter downstream the IP will measure the disrupted beam resulting in high background and much lower statistics, but it allows access to the depolarization at the IP. Cross checks between the polarimeter results give redundancy and inter-calibration which is essential for high precision measurements. Current plans and issues for polarimeters and also energy spectrometers in the Beam Delivery System of the ILC are summarized in reference [28]. The ILC baseline design allows already from the beginning the operation with polarized electrons and polarized positrons provided the spin rotation and the fast helicity reversal for positrons will be implemented. A reversal of the positron helicity significantly slower than that of electrons is not recommended to not compromise the precision and hence the success of the ILC. Recently to use calibration data at the Z

  16. KRAM, A lattice physics code for modeling the detailed depletion of gadolinia isotopes in BWR lattice designs

    SciTech Connect

    Knott, D.; Baratta, A. )

    1990-01-01

    Lattice physics codes are used to deplete the burnable isotopes present in each lattice design, calculate the buildup of fission products, and generate the few-group cross-section data needed by the various nodal simulator codes. Normally, the detailed depletion of gadolinia isotopes is performed outside the lattice physics code in a one-dimensional environment using an onion-skin model, such as the method used in MICBURN. Results from the onion-skin depletion, in the form of effective microscopic absorption cross sections for the gadolinia, are then used by the lattice physics code during the lattice-depletion analysis. The reactivity of the lattice at any point in the cycle depends to a great extent on the amount of gadolinia present. In an attempt to improve the modeling of gadolinia depletion from fresh boiling water reactor (BWR) fuel designs, the electric Power Research Institute (EPRI) lattice-physics code CPM-2 has been modified extensively. In this paper, the modified code KRAM is described, and results from various lattice-depletion analyses are discussed in comparison with results from standard CPM-2 and CASMO-2 analyses.

  17. Physical processes at work in sub-30 fs, PW laser pulse-driven plasma accelerators: Towards GeV electron acceleration experiments at CILEX facility

    NASA Astrophysics Data System (ADS)

    Beck, A.; Kalmykov, S. Y.; Davoine, X.; Lifschitz, A.; Shadwick, B. A.; Malka, V.; Specka, A.

    2014-03-01

    Optimal regimes and physical processes at work are identified for the first round of laser wakefield acceleration experiments proposed at a future CILEX facility. The Apollon-10P CILEX laser, delivering fully compressed, near-PW-power pulses of sub-25 fs duration, is well suited for driving electron density wakes in the blowout regime in cm-length gas targets. Early destruction of the pulse (partly due to energy depletion) prevents electrons from reaching dephasing, limiting the energy gain to about 3 GeV. However, the optimal operating regimes, found with reduced and full three-dimensional particle-in-cell simulations, show high energy efficiency, with about 10% of incident pulse energy transferred to 3 GeV electron bunches with sub-5% energy spread, half-nC charge, and absolutely no low-energy background. This optimal acceleration occurs in 2 cm length plasmas of electron density below 1018 cm-3. Due to their high charge and low phase space volume, these multi-GeV bunches are tailor-made for staged acceleration planned in the framework of the CILEX project. The hallmarks of the optimal regime are electron self-injection at the early stage of laser pulse propagation, stable self-guiding of the pulse through the entire acceleration process, and no need for an external plasma channel. With the initial focal spot closely matched for the nonlinear self-guiding, the laser pulse stabilizes transversely within two Rayleigh lengths, preventing subsequent evolution of the accelerating bucket. This dynamics prevents continuous self-injection of background electrons, preserving low phase space volume of the bunch through the plasma. Near the end of propagation, an optical shock builds up in the pulse tail. This neither disrupts pulse propagation nor produces any noticeable low-energy background in the electron spectra, which is in striking contrast with most of existing GeV-scale acceleration experiments.

  18. Accelerator Technology and High Energy Physics Experiments, Photonics Applications and Web Engineering, Wilga, May 2012

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2012-05-01

    The paper is the second part (out of five) of the research survey of WILGA Symposium work, May 2012 Edition, concerned with accelerator technology and high energy physics experiments. It presents a digest of chosen technical work results shown by young researchers from different technical universities from this country during the XXXth Jubilee SPIE-IEEE Wilga 2012, May Edition, symposium on Photonics and Web Engineering. Topical tracks of the symposium embraced, among others, nanomaterials and nanotechnologies for photonics, sensory and nonlinear optical fibers, object oriented design of hardware, photonic metrology, optoelectronics and photonics applications, photonicselectronics co-design, optoelectronic and electronic systems for astronomy and high energy physics experiments, JET and pi-of-the sky experiments development. The symposium is an annual summary in the development of numerable Ph.D. theses carried out in this country in the area of advanced electronic and photonic systems. It is also a great occasion for SPIE, IEEE, OSA and PSP students to meet together in a large group spanning the whole country with guests from this part of Europe. A digest of Wilga references is presented [1-275].

  19. Physics-Based Fragment Acceleration Modeling for Pressurized Tank Burst Risk Assessments

    NASA Technical Reports Server (NTRS)

    Manning, Ted A.; Lawrence, Scott L.

    2014-01-01

    As part of comprehensive efforts to develop physics-based risk assessment techniques for space systems at NASA, coupled computational fluid and rigid body dynamic simulations were carried out to investigate the flow mechanisms that accelerate tank fragments in bursting pressurized vessels. Simulations of several configurations were compared to analyses based on the industry-standard Baker explosion model, and were used to formulate an improved version of the model. The standard model, which neglects an external fluid, was found to agree best with simulation results only in configurations where the internal-to-external pressure ratio is very high and fragment curvature is small. The improved model introduces terms that accommodate an external fluid and better account for variations based on circumferential fragment count. Physics-based analysis was critical in increasing the model's range of applicability. The improved tank burst model can be used to produce more accurate risk assessments of space vehicle failure modes that involve high-speed debris, such as exploding propellant tanks and bursting rocket engines.

  20. Detailed Modeling of Physical Processes in Electron Sources for Accelerator Applications

    NASA Astrophysics Data System (ADS)

    Chubenko, Oksana; Afanasev, Andrei

    2017-01-01

    At present, electron sources are essential in a wide range of applications - from common technical use to exploring the nature of matter. Depending on the application requirements, different methods and materials are used to generate electrons. State-of-the-art accelerator applications set a number of often-conflicting requirements for electron sources (e.g., quantum efficiency vs. polarization, current density vs. lifetime, etc). Development of advanced electron sources includes modeling and design of cathodes, material growth, fabrication of cathodes, and cathode testing. The detailed simulation and modeling of physical processes is required in order to shed light on the exact mechanisms of electron emission and to develop new-generation electron sources with optimized efficiency. The purpose of the present work is to study physical processes in advanced electron sources and develop scientific tools, which could be used to predict electron emission from novel nano-structured materials. In particular, the area of interest includes bulk/superlattice gallium arsenide (bulk/SL GaAs) photo-emitters and nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) photo/field-emitters. Work supported by The George Washington University and Euclid TechLabs LLC.

  1. The physics of compensating calorimetry and the new CALOR89 code system

    SciTech Connect

    Gabriel, T.A.; Brau, J.E.; Bishop, B.L.

    1989-03-01

    Much of the understanding of the physics of calorimetry has come from the use of excellent radiation transport codes. A new understanding of compensating calorimetry was introduced four years ago following detailed studies with a new CALOR system. Now, the CALOR system has again been revised to reflect a better comprehension of high energy nuclear collisions by incorporating a modified high energy fragmentation model from FLUKA87. This revision will allow for the accurate analysis of calorimeters at energies of 100's of GeV. Presented in this paper is a discussion of compensating calorimetry, the new CALOR system, the revisions to HETC, and recently generated calorimeter related data on modes of energy deposition and secondary neutron production (E < 50 MeV) in infinite iron and uranium blocks. 38 refs., 5 figs., 5 tabs.

  2. DNA as a Binary Code: How the Physical Structure of Nucleotide Bases Carries Information

    ERIC Educational Resources Information Center

    McCallister, Gary

    2005-01-01

    The DNA triplet code also functions as a binary code. Because double-ring compounds cannot bind to double-ring compounds in the DNA code, the sequence of bases classified simply as purines or pyrimidines can encode for smaller groups of possible amino acids. This is an intuitive approach to teaching the DNA code. (Contains 6 figures.)

  3. Mount Aragats as a stable electron accelerator for atmospheric high-energy physics research

    NASA Astrophysics Data System (ADS)

    Chilingarian, Ashot; Hovsepyan, Gagik; Mnatsakanyan, Eduard

    2016-03-01

    Observation of the numerous thunderstorm ground enhancements (TGEs), i.e., enhanced fluxes of electrons, gamma rays, and neutrons detected by particle detectors located on the Earth's surface and related to the strong thunderstorms above it, helped to establish a new scientific topic—high-energy physics in the atmosphere. Relativistic runaway electron avalanches (RREAs) are believed to be a central engine initiating high-energy processes in thunderstorm atmospheres. RREAs observed on Mount Aragats in Armenia during the strongest thunderstorms and simultaneous measurements of TGE electron and gamma-ray energy spectra proved that RREAs are a robust and realistic mechanism for electron acceleration. TGE research facilitates investigations of the long-standing lightning initiation problem. For the last 5 years we were experimenting with the "beams" of "electron accelerators" operating in the thunderclouds above the Aragats research station. Thunderstorms are very frequent above Aragats, peaking in May-June, and almost all of them are accompanied with enhanced particle fluxes. The station is located on a plateau at an altitude 3200 asl near a large lake. Numerous particle detectors and field meters are located in three experimental halls as well as outdoors; the facilities are operated all year round. All relevant information is being gathered, including data on particle fluxes, fields, lightning occurrences, and meteorological conditions. By the example of the huge thunderstorm that took place at Mount Aragats on August 28, 2015, we show that simultaneous detection of all the relevant data allowed us to reveal the temporal pattern of the storm development and to investigate the atmospheric discharges and particle fluxes.

  4. Third order TRANSPORT with MAD (Methodical Accelerator Design) input

    SciTech Connect

    Carey, D.C.

    1988-09-20

    This paper describes computer-aided design codes for particle accelerators. Among the topics discussed are: input beam description; parameters and algebraic expressions; the physical elements; beam lines; operations; and third-order transfer matrix. (LSP)

  5. Additions and improvements to the high energy density physics capabilities in the FLASH code

    NASA Astrophysics Data System (ADS)

    Lamb, D. Q.; Flocke, N.; Graziani, C.; Tzeferacos, P.; Weide, K.

    2016-10-01

    FLASH is an open source, finite-volume Eulerian, spatially adaptive radiation magnetohydrodynamics code that has the capabilities to treat a broad range of physical processes. FLASH performs well on a wide range of computer architectures, and has a broad user base. Extensive high energy density physics (HEDP) capabilities have been added to FLASH to make it an open toolset for the academic HEDP community. We summarize these capabilities, emphasizing recent additions and improvements. In particular, we showcase the ability of FLASH to simulate the Faraday Rotation Measure produced by the presence of magnetic fields; and proton radiography, proton self-emission, and Thomson scattering diagnostics with and without the presence of magnetic fields. We also describe several collaborations with the academic HEDP community in which FLASH simulations were used to design and interpret HEDP experiments. This work was supported in part at the University of Chicago by the DOE NNSA ASC through the Argonne Institute for Computing in Science under field work proposal 57789; and the NSF under Grant PHY-0903997.

  6. Contemporary stellar evolution codes: physics under the bonnet and implications for asteroseismology

    NASA Astrophysics Data System (ADS)

    Stancliffe, Richard James

    2015-08-01

    Just how good are modern stellar models? Providing a rigorous assessment of the uncertainties is difficult because of the multiplicity of input physics. Some of the ingredients are reasonably well-known (like reaction rates and opacities). Others are not so good, with convection standing out as a particularly obvious example. In some cases, it is not clear what the ingredients should be -- what role do atomic diffusion, rotation, magnetic fields, etc. play in stellar evolution? All this is then compounded by computational method. In converting all this physics into something we can implement in a 1D evolution code, we are forced to make choices about the way the equations are solved, how we will treat mixing at convective boundaries, etc. All of this can impact the models one finally generates.In this review, I will attempt to assess the uncertainties associated with the ingredients and methods used by stellar evolution modellers, and what their impacts may be on the science that we wish to do.

  7. Operational Radiation Protection in High-Energy Physics Accelerators: Implementation of ALARA in Design and Operation of Accelerators

    SciTech Connect

    Fasso, A.; Rokni, S.; /SLAC

    2011-06-30

    It used to happen often, to us accelerator radiation protection staff, to be asked by a new radiation worker: ?How much dose am I still allowed?? And we smiled looking at the shocked reaction to our answer: ?You are not allowed any dose?. Nowadays, also thanks to improved training programs, this kind of question has become less frequent, but it is still not always easy to convince workers that staying below the exposure limits is not sufficient. After all, radiation is still the only harmful agent for which this is true: for all other risks in everyday life, from road speed limits to concentration of hazardous chemicals in air and water, compliance to regulations is ensured by keeping below a certain value. It appears that a tendency is starting to develop to extend the radiation approach to other pollutants (1), but it will take some time before the new attitude makes it way into national legislations.

  8. Porting plasma physics simulation codes to modern computing architectures using the libmrc framework

    NASA Astrophysics Data System (ADS)

    Germaschewski, Kai; Abbott, Stephen

    2015-11-01

    Available computing power has continued to grow exponentially even after single-core performance satured in the last decade. The increase has since been driven by more parallelism, both using more cores and having more parallelism in each core, e.g. in GPUs and Intel Xeon Phi. Adapting existing plasma physics codes is challenging, in particular as there is no single programming model that covers current and future architectures. We will introduce the open-source libmrc framework that has been used to modularize and port three plasma physics codes: The extended MHD code MRCv3 with implicit time integration and curvilinear grids; the OpenGGCM global magnetosphere model; and the particle-in-cell code PSC. libmrc consolidates basic functionality needed for simulations based on structured grids (I/O, load balancing, time integrators), and also introduces a parallel object model that makes it possible to maintain multiple implementations of computational kernels, on e.g. conventional processors and GPUs. It handles data layout conversions and enables us to port performance-critical parts of a code to a new architecture step-by-step, while the rest of the code can remain unchanged. We will show examples of the performance gains and some physics applications.

  9. Optimization and parallelization of the thermal–hydraulic subchannel code CTF for high-fidelity multi-physics applications

    DOE PAGES

    Salko, Robert K.; Schmidt, Rodney C.; Avramova, Maria N.

    2014-11-23

    This study describes major improvements to the computational infrastructure of the CTF subchannel code so that full-core, pincell-resolved (i.e., one computational subchannel per real bundle flow channel) simulations can now be performed in much shorter run-times, either in stand-alone mode or as part of coupled-code multi-physics calculations. These improvements support the goals of the Department Of Energy Consortium for Advanced Simulation of Light Water Reactors (CASL) Energy Innovation Hub to develop high fidelity multi-physics simulation tools for nuclear energy design and analysis.

  10. On the physics of waves in the solar atmosphere: Wave heating and wind acceleration

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1993-01-01

    This paper presents work performed on the generation and physics of acoustic waves in the solar atmosphere. The investigators have incorporated spatial and temporal turbulent energy spectra in a newly corrected version of the Lighthill-Stein theory of acoustic wave generation in order to calculate the acoustic wave energy fluxes generated in the solar convective zone. The investigators have also revised and improved the treatment of the generation of magnetic flux tube waves, which can carry energy along the tubes far away from the region of their origin, and have calculated the tube energy fluxes for the sun. They also examine the transfer of the wave energy originated in the solar convective zone to the outer atmospheric layers through computation of wave propagation and dissipation in highly nonhomogeneous solar atmosphere. These waves may efficiently heat the solar atmosphere and the heating will be especially significant in the chromospheric network. It is also shown that the role played by Alfven waves in solar wind acceleration and coronal hole heating is dominant. The second part of the project concerned investigation of wave propagation in highly inhomogeneous stellar atmospheres using an approach based on an analytic tool developed by Musielak, Fontenla, and Moore. In addition, a new technique based on Dirac equations has been developed to investigate coupling between different MHD waves propagating in stratified stellar atmospheres.

  11. On the physics of waves in the solar atmosphere: Wave heating and wind acceleration

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1994-01-01

    This paper presents work performed on the generation and physics of acoustic waves in the solar atmosphere. The investigators have incorporated spatial and temporal turbulent energy spectra in a newly corrected version of the Lighthill-Stein theory of acoustic wave generation in order to calculate the acoustic wave energy fluxes generated in the solar convective zone. The investigators have also revised and improved the treatment of the generation of magnetic flux tube waves, which can carry energy along the tubes far away from the region of their origin, and have calculated the tube wave energy fluxes for the sun. They also examine the transfer of the wave energy originated in the solar convective zone to the outer atmospheric layers through computation of wave propagation and dissipation in highly nonhomogeneous solar atmosphere. These waves may efficiently heat the solar atmosphere and the heating will be especially significant in the chromospheric network. It is also shown that the role played by Alfven waves in solar wind acceleration and coronal hole heating is dominant. The second part of the project concerned investigation of wave propagation in highly inhomogeneous stellar atmospheres using an approach based on an analytic tool developed by Musielak, Fontenla, and Moore. In addition, a new technique based on Dirac equations has been developed to investigate coupling between different MHD waves propagating in stratified stellar atmospheres.

  12. Comparison of dosimetric characteristics of Siemens virtual and physical wedges for ONCOR linear accelerator.

    PubMed

    Attalla, Ehab M; Abo-Elenein, H S; Ammar, H; El-Desoky, Ismail

    2010-07-01

    Dosimetric properties of virtual wedge (VW) and physical wedge (PW) in 6- and 10-MV photon beams from a Siemens ONCOR linear accelerator, including wedge factors, depth doses, dose profiles, peripheral doses, are compared. While there is a great difference in absolute values of wedge factors, VW factors (VWFs) and PW factors (PWFs) have a similar trend as a function of field size. PWFs have stronger depth dependence than VWF due to beam hardening in PW fields. VW dose profiles in the wedge direction, in general, match very well with those of PW, except in the toe area of large wedge angles with large field sizes. Dose profiles in the nonwedge direction show a significant reduction in PW fields due to off-axis beam softening and oblique filtration. PW fields have significantly higher peripheral doses than open and VW fields. VW fields have similar surface doses as the open fields, while PW fields have lower surface doses. Surface doses for both VW and PW increase with field size and slightly with wedge angle. For VW fields with wedge angles 45° and less, the initial gap up to 3 cm is dosimetrically acceptable when compared to dose profiles of PW. VW fields in general use less monitor units than PW fields.

  13. Supercomputing with TOUGH2 family codes for coupled multi-physics simulations of geologic carbon sequestration

    NASA Astrophysics Data System (ADS)

    Yamamoto, H.; Nakajima, K.; Zhang, K.; Nanai, S.

    2015-12-01

    Powerful numerical codes that are capable of modeling complex coupled processes of physics and chemistry have been developed for predicting the fate of CO2 in reservoirs as well as its potential impacts on groundwater and subsurface environments. However, they are often computationally demanding for solving highly non-linear models in sufficient spatial and temporal resolutions. Geological heterogeneity and uncertainties further increase the challenges in modeling works. Two-phase flow simulations in heterogeneous media usually require much longer computational time than that in homogeneous media. Uncertainties in reservoir properties may necessitate stochastic simulations with multiple realizations. Recently, massively parallel supercomputers with more than thousands of processors become available in scientific and engineering communities. Such supercomputers may attract attentions from geoscientist and reservoir engineers for solving the large and non-linear models in higher resolutions within a reasonable time. However, for making it a useful tool, it is essential to tackle several practical obstacles to utilize large number of processors effectively for general-purpose reservoir simulators. We have implemented massively-parallel versions of two TOUGH2 family codes (a multi-phase flow simulator TOUGH2 and a chemically reactive transport simulator TOUGHREACT) on two different types (vector- and scalar-type) of supercomputers with a thousand to tens of thousands of processors. After completing implementation and extensive tune-up on the supercomputers, the computational performance was measured for three simulations with multi-million grid models, including a simulation of the dissolution-diffusion-convection process that requires high spatial and temporal resolutions to simulate the growth of small convective fingers of CO2-dissolved water to larger ones in a reservoir scale. The performance measurement confirmed that the both simulators exhibit excellent

  14. Status of MARS Code

    SciTech Connect

    N.V. Mokhov

    2003-04-09

    Status and recent developments of the MARS 14 Monte Carlo code system for simulation of hadronic and electromagnetic cascades in shielding, accelerator and detector components in the energy range from a fraction of an electronvolt up to 100 TeV are described. these include physics models both in strong and electromagnetic interaction sectors, variance reduction techniques, residual dose, geometry, tracking, histograming. MAD-MARS Beam Line Build and Graphical-User Interface.

  15. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  16. Letters What causes an ice skater to accelerate? Note on the definitions of weight A-level physics is mathematical enough Correction to 'Confusion over the physics of circular motion'

    NASA Astrophysics Data System (ADS)

    2011-11-01

    What causes an ice skater to accelerate? Hugh Fricker Note on the definitions of weight Nenad Stojilovic A-level physics is mathematical enough Helen Hare Correction to 'Confusion over the physics of circular motion'

  17. New VACUUM: towards an object oriented version of the code with additional physics capability

    NASA Astrophysics Data System (ADS)

    Chance, M. S.; Pletzer, A.; Okabayashi, M.; Chu, M. S.; Turnbull, A. D.; Glasser, A. H.

    2001-10-01

    The VACUUM Code^a which was initially created to provide the outer boundary conditions and diagnostics to the PEST and NOVA Fourier codes has been substantially modified to be interfaced to a variety of other stability codes, including DCON, the finite element GATO code as well as the nonlinear NIMROD and M3D codes. It now also includes the ability to model the feedback stabilization of external MHD modes in tokamaks so that the effects of a thin resistive shell and the feedback circuitry together with the associated sensor loops and feedback coils are incorporated. To improve the interface to an increasing number of codes, structural changes addressing portability and memory management are under development: A Fortran 90 version of the code using dynamic memory allocation is in progress, and furthermore, VACUUM will be transformed from a standalone code using I/O files to one using a set of library calls where input and output data are communicated through "set" and "get" calls. The benefit of such an application programming interface (API) layout is to allow VACUUM to be embedded in large packages (e.g. TRANSP) , scripting environments (e.g. Python, Matlab, IDL) or wrapped into C++ code to provide object oriented features. ^aM.S. Chance, Phys. Plasmas 4, 2161 (1997).

  18. Benchmarking the SPHINX and CTH shock physics codes for three problems in ballistics

    SciTech Connect

    Wilson, L.T.; Hertel, E.; Schwalbe, L.; Wingate, C.

    1998-02-01

    The CTH Eulerian hydrocode, and the SPHINX smooth particle hydrodynamics (SPH) code were used to model a shock tube, two long rod penetrations into semi-infinite steel targets, and a long rod penetration into a spaced plate array. The results were then compared to experimental data. Both SPHINX and CTH modeled the one-dimensional shock tube problem well. Both codes did a reasonable job in modeling the outcome of the axisymmetric rod impact problem. Neither code correctly reproduced the depth of penetration in both experiments. In the 3-D problem, both codes reasonably replicated the penetration of the rod through the first plate. After this, however, the predictions of both codes began to diverge from the results seen in the experiment. In terms of computer resources, the run times are problem dependent, and are discussed in the text.

  19. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Awe, T. J.; Bailey, J. E.; Bennett, N. L.; Breden, E. W.; Campbell, E. M.; Clark, R. E.; Cooper, R. A.; Cuneo, M. E.; Ennis, J. B.; Fehl, D. L.; Genoni, T. C.; Gomez, M. R.; Greiser, G. W.; Gruner, F. R.; Herrmann, M. C.; Hutsel, B. T.; Jennings, C. A.; Jobe, D. O.; Jones, B. M.; Jones, M. C.; Jones, P. A.; Knapp, P. F.; Lash, J. S.; LeChien, K. R.; Leckbee, J. J.; Leeper, R. J.; Lewis, S. A.; Long, F. W.; Lucero, D. J.; Madrid, E. A.; Martin, M. R.; Matzen, M. K.; Mazarakis, M. G.; McBride, R. D.; McKee, G. R.; Miller, C. L.; Moore, J. K.; Mostrom, C. B.; Mulville, T. D.; Peterson, K. J.; Porter, J. L.; Reisman, D. B.; Rochau, G. A.; Rochau, G. E.; Rose, D. V.; Rovang, D. C.; Savage, M. E.; Sceiford, M. E.; Schmit, P. F.; Schneider, R. F.; Schwarz, J.; Sefkow, A. B.; Sinars, D. B.; Slutz, S. A.; Spielman, R. B.; Stoltzfus, B. S.; Thoma, C.; Vesey, R. A.; Wakeland, P. E.; Welch, D. R.; Wisher, M. L.; Woodworth, J. R.

    2015-11-01

    We have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated by the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator's water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator's physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD) simulations

  20. J-PAS: The Javalambre Physics of the Accelerated Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Cepa, J.; Benítez, N.; Dupke, R.; Moles, M.; Sodré, L.; Cenarro, A. J.; Marín-Franch, A.; Taylor, K.; Cristóbal, D.; Fernández-Soto, A.; Mendes de Oliveira, C.; Abramo, L. R.; Alcaniz, J. S.; Overzier, R.; Hernández-Monteagudo, A.; Alfaro, E. J.; Kanaan, A.; Carvano, M.; Reis, R. R. R.; J-PAS Team

    2016-10-01

    The Javalambre Physics of the Accelerated Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Observatory in Spain with a purpose-built, dedicated 2.5 m telescope and a 4.7 sq.deg. camera with 1.2 Gpix. Starting in late 2016, J-PAS will observe 8500 sq.deg. of Northern Sky and measure Δz˜0.003(1+z) photo-z for 9× 107 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ˜ 14 Gpc3 up to z=1.3 and becoming the first radial BAO experiment to reach Stage IV. J-PAS will detect 7× 105 galaxy clusters and groups, setting constraints on Dark Energy which rival those obtained from its BAO measurements. Thanks to the superb characteristics of the site (seeing ˜ 0.7 arcsec), J-PAS is expected to obtain a deep, sub-arcsec image of the Northern sky, which combined with its unique photo-z precision will produce one of the most powerful cosmological lensing surveys before the arrival of Euclid. J-PAS's unprecedented spectral time domain information will enable a self-contained SN survey that, without the need for external spectroscopic follow-up, will detect, classify and measure σz˜ 0.5 redshifts for ˜ 4000 SNeIa and ˜ 900 core-collapse SNe. The key to the J-PAS potential is its innovative approach: a contiguous system of 54 filters with 145 Å width, placed 100 Å apart over a multi-degree FoV is a powerful redshift machine, with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. The J-PAS camera is equivalent to a 4.7 sq.deg. IFU and it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations.

  1. Physics issues in the design of a recirculating induction accelerator for heavy ion fusion

    SciTech Connect

    Barnard, J.J.; Newton, M.A.; Reginato, L.L.; Sharp, W.M.; Yu, S.S.

    1991-04-15

    A substantial savings in size and cost over a linear machine may be achieved in an induction accelerator in which a heavy ion beam makes many (< {approximately} 50) passes through one or more circular induction accelerators. We examine how the requirement of high beam quality and the requirement of pulse simultaneity at the target constrain the design of such an accelerator. Some of the issues that we have considered include beam interactions with residual gas, beam-beam charge exchange, emittance growth around bends, and beam instabilities. We show some of the interplay between maximization of beam quality and recirculator efficiency, and the minimization of recirculator cost, in arriving at a recirculator design. 9 refs., 1 fig.

  2. User's manual for ONEDANT: a code package for one-dimensional, diffusion-accelerated, neutral-particle transport

    SciTech Connect

    O'Dell, R.D.; Brinkley, F.W. Jr.; Marr, D.R.

    1982-02-01

    ONEDANT is designed for the CDC-7600, but the program has been implemented and run on the IBM-370/190 and CRAY-I computers. ONEDANT solves the one-dimensional multigroup transport equation in plane, cylindrical, spherical, and two-angle plane geometries. Both regular and adjoint, inhomogeneous and homogeneous (k/sub eff/ and eigenvalue search) problems subject to vacuum, reflective, periodic, white, albedo, or inhomogeneous boundary flux conditions are solved. General anisotropic scattering is allowed and anisotropic inhomogeneous sources are permitted. ONEDANT numerically solves the one-dimensional, multigroup form of the neutral-particle, steady-state form of the Boltzmann transport equation. The discrete-ordinates approximation is used for treating the angular variation of the particle distribution and the diamond-difference scheme is used for phase space discretization. Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm. A standard inner (within-group) iteration, outer (energy-group-dependent source) iteration technique is used. Both inner and outer iterations are accelerated using the diffusion synthetic acceleration method. (WHK)

  3. The Use of Acceleration to Code for Animal Behaviours; A Case Study in Free-Ranging Eurasian Beavers Castor fiber.

    PubMed

    Graf, Patricia M; Wilson, Rory P; Qasem, Lama; Hackländer, Klaus; Rosell, Frank

    2015-01-01

    Recent technological innovations have led to the development of miniature, accelerometer-containing electronic loggers which can be attached to free-living animals. Accelerometers provide information on both body posture and dynamism which can be used as descriptors to define behaviour. We deployed tri-axial accelerometer loggers on 12 free-ranging Eurasian beavers Castor fiber in the county of Telemark, Norway, and on four captive beavers (two Eurasian beavers and two North American beavers C. canadensis) to corroborate acceleration signals with observed behaviours. By using random forests for classifying behavioural patterns of beavers from accelerometry data, we were able to distinguish seven behaviours; standing, walking, swimming, feeding, grooming, diving and sleeping. We show how to apply the use of acceleration to determine behaviour, and emphasise the ease with which this non-invasive method can be implemented. Furthermore, we discuss the strengths and weaknesses of this, and the implementation of accelerometry on animals, illustrating limitations, suggestions and solutions. Ultimately, this approach may also serve as a template facilitating studies on other animals with similar locomotor modes and deliver new insights into hitherto unknown aspects of behavioural ecology.

  4. The Use of Acceleration to Code for Animal Behaviours; A Case Study in Free-Ranging Eurasian Beavers Castor fiber

    PubMed Central

    Graf, Patricia M.; Wilson, Rory P.; Qasem, Lama; Hackländer, Klaus; Rosell, Frank

    2015-01-01

    Recent technological innovations have led to the development of miniature, accelerometer-containing electronic loggers which can be attached to free-living animals. Accelerometers provide information on both body posture and dynamism which can be used as descriptors to define behaviour. We deployed tri-axial accelerometer loggers on 12 free-ranging Eurasian beavers Castor fiber in the county of Telemark, Norway, and on four captive beavers (two Eurasian beavers and two North American beavers C. canadensis) to corroborate acceleration signals with observed behaviours. By using random forests for classifying behavioural patterns of beavers from accelerometry data, we were able to distinguish seven behaviours; standing, walking, swimming, feeding, grooming, diving and sleeping. We show how to apply the use of acceleration to determine behaviour, and emphasise the ease with which this non-invasive method can be implemented. Furthermore, we discuss the strengths and weaknesses of this, and the implementation of accelerometry on animals, illustrating limitations, suggestions and solutions. Ultimately, this approach may also serve as a template facilitating studies on other animals with similar locomotor modes and deliver new insights into hitherto unknown aspects of behavioural ecology. PMID:26317623

  5. The development and performance of a message-passing version of the PAGOSA shock-wave physics code

    SciTech Connect

    Gardner, D.R.; Vaughan, C.T.

    1997-10-01

    A message-passing version of the PAGOSA shock-wave physics code has been developed at Sandia National Laboratories for multiple-instruction, multiple-data stream (MIMD) computers. PAGOSA is an explicit, Eulerian code for modeling the three-dimensional, high-speed hydrodynamic flow of fluids and the dynamic deformation of solids under high rates of strain. It was originally developed at Los Alamos National Laboratory for the single-instruction, multiple-data (SIMD) Connection Machine parallel computers. The performance of Sandia`s message-passing version of PAGOSA has been measured on two MIMD machines, the nCUBE 2 and the Intel Paragon XP/S. No special efforts were made to optimize the code for either machine. The measured scaled speedup (computational time for a single computational node divided by the computational time per node for fixed computational load) and grind time (computational time per cell per time step) show that the MIMD PAGOSA code scales linearly with the number of computational nodes used on a variety of problems, including the simulation of shaped-charge jets perforating an oil well casing. Scaled parallel efficiencies for MIMD PAGOSA are greater than 0.70 when the available memory per node is filled (or nearly filled) on hundreds to a thousand or more computational nodes on these two machines, indicating that the code scales very well. Thus good parallel performance can be achieved for complex and realistic applications when they are first implemented on MIMD parallel computers.

  6. A Treasure Trove of Physics from a Common Source-Automobile Acceleration Data

    NASA Astrophysics Data System (ADS)

    Graney, Christopher M.

    2005-11-01

    What is better than interesting, challenging physics with good data free for the taking to which everyone can relate? That's what is available to anyone who digs into the reams of automobile performance tests that have been available in popular magazines since the 1950s. Opportunities to do and teach interesting physics abound, as evidenced by the frequent appearance of "physics of cars" articles in The Physics Teacher.1-6

  7. Physics of Phase Space Matching for Staging Plasma and Traditional Accelerator Components Using Longitudinally Tailored Plasma Profiles.

    PubMed

    Xu, X L; Hua, J F; Wu, Y P; Zhang, C J; Li, F; Wan, Y; Pai, C-H; Lu, W; An, W; Yu, P; Hogan, M J; Joshi, C; Mori, W B

    2016-03-25

    Phase space matching between two plasma-based accelerator (PBA) stages and between a PBA and a traditional accelerator component is a critical issue for emittance preservation. The drastic differences of the transverse focusing strengths as the beam propagates between stages and components may lead to a catastrophic emittance growth even when there is a small energy spread. We propose using the linear focusing forces from nonlinear wakes in longitudinally tailored plasma density profiles to control phase space matching between sections with negligible emittance growth. Several profiles are considered and theoretical analysis and particle-in-cell simulations show how these structures may work in four different scenarios. Good agreement between theory and simulation is obtained, and it is found that the adiabatic approximation misses important physics even for long profiles.

  8. Final Report for "Non-Accelerator Physics – Research in High Energy Physics: Dark Energy Research on DES"

    SciTech Connect

    Ritz, Steve; Jeltema, Tesla

    2016-12-01

    One of the greatest mysteries in modern cosmology is the fact that the expansion of the universe is observed to be accelerating. This acceleration may stem from dark energy, an additional energy component of the universe, or may indicate that the theory of general relativity is incomplete on cosmological scales. The growth rate of large-scale structure in the universe and particularly the largest collapsed structures, clusters of galaxies, is highly sensitive to the underlying cosmology. Clusters will provide one of the single most precise methods of constraining dark energy with the ongoing Dark Energy Survey (DES). The accuracy of the cosmological constraints derived from DES clusters necessarily depends on having an optimized and well-calibrated algorithm for selecting clusters as well as an optical richness estimator whose mean relation and scatter compared to cluster mass are precisely known. Calibrating the galaxy cluster richness-mass relation and its scatter was the focus of the funded work. Specifically, we employ X-ray observations and optical spectroscopy with the Keck telescopes of optically-selected clusters to calibrate the relationship between optical richness (the number of galaxies in a cluster) and underlying mass. This work also probes aspects of cluster selection like the accuracy of cluster centering which are critical to weak lensing cluster studies.

  9. Studies of the chromatic properties and dynamic aperture of the BNL colliding-beam accelerator. [PATRICIA particle tracking code

    SciTech Connect

    Dell, G.F.

    1983-01-01

    The PATRICIA particle tracking program has been used to study chromatic effects in the Brookhaven CBA (Colliding Beam Accelerator). The short term behavior of particles in the CBA has been followed for particle histories of 300 turns. Contributions from magnet multipoles characteristic of superconducting magnets and closed orbit errors have been included in determining the dynamic aperture of the CBA for on and off momentum particles. The width of the third integer stopband produced by the temperature dependence of magnetization induced sextupoles in the CBA cable dipoles is evaluated for helium distribution systems having periodicity of one and six. The stopband width at a tune of 68/3 is naturally zero for the system having a periodicity of six and is approx. 10/sup -4/ for the system having a periodicity of one. Results from theory are compared with results obtained with PATRICIA; the results agree within a factor of slightly more than two.

  10. Evaluation using m.c.n.p. code of the bremsstrahlung energy spectrum produced by interactions between structural materials and accelerated electrons

    NASA Astrophysics Data System (ADS)

    Calderaro, Elio

    2004-09-01

    In order to design the biological shield of industrial accelerator plants, it is needed to have a good knowledge of the bremsstrahlung energy spectrum and the intensity of the bremsstrahlung produced by electron interactions with both products (usually water equivalent) and structural materials such as concrete, iron, aluminium. Using the MCNP code, a normalized bremsstrahlung energy spectrum was obtained for materials with average atomic number lower than or equal to 13 and irradiated with 5 and 10 Mev electrons, respectively; multiplying the spectrum by suitable coefficients, it was possible to obtain the real spectrum for materials such as water, concrete, aluminium and iron. The MCNP results have been obtained with relative error less than 2%.

  11. Conceptual design of a 1013 -W pulsed-power accelerator for megajoule-class dynamic-material-physics experiments

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Reisman, D. B.; Stoltzfus, B. S.; Austin, K. N.; Ao, T.; Benage, J. F.; Breden, E. W.; Cooper, R. A.; Cuneo, M. E.; Davis, J.-P.; Ennis, J. B.; Gard, P. D.; Greiser, G. W.; Gruner, F. R.; Haill, T. A.; Hutsel, B. T.; Jones, P. A.; LeChien, K. R.; Leckbee, J. J.; Lewis, S. A.; Lucero, D. J.; McKee, G. R.; Moore, J. K.; Mulville, T. D.; Muron, D. J.; Root, S.; Savage, M. E.; Sceiford, M. E.; Spielman, R. B.; Waisman, E. M.; Wisher, M. L.

    2016-07-01

    We have developed a conceptual design of a next-generation pulsed-power accelerator that is optimized for megajoule-class dynamic-material-physics experiments. Sufficient electrical energy is delivered by the accelerator to a physics load to achieve—within centimeter-scale samples—material pressures as high as 1 TPa. The accelerator design is based on an architecture that is founded on three concepts: single-stage electrical-pulse compression, impedance matching, and transit-time-isolated drive circuits. The prime power source of the accelerator consists of 600 independent impedance-matched Marx generators. Each Marx comprises eight 5.8-GW bricks connected electrically in series, and generates a 100-ns 46-GW electrical-power pulse. A 450-ns-long water-insulated coaxial-transmission-line impedance transformer transports the power generated by each Marx to a system of twelve 2.5-m-radius water-insulated conical transmission lines. The conical lines are connected electrically in parallel at a 66-cm radius by a water-insulated 45-post sextuple-post-hole convolute. The convolute sums the electrical currents at the outputs of the conical lines, and delivers the combined current to a single solid-dielectric-insulated radial transmission line. The radial line in turn transmits the combined current to the load. Since much of the accelerator is water insulated, we refer to it as Neptune. Neptune is 40 m in diameter, stores 4.8 MJ of electrical energy in its Marx capacitors, and generates 28 TW of peak electrical power. Since the Marxes are transit-time isolated from each other for 900 ns, they can be triggered at different times to construct-over an interval as long as 1 μ s -the specific load-current time history required for a given experiment. Neptune delivers 1 MJ and 20 MA in a 380-ns current pulse to an 18 -m Ω load; hence Neptune is a megajoule-class 20-MA arbitrary waveform generator. Neptune will allow the international scientific community to conduct dynamic

  12. HELIOS: An Open-source, GPU-accelerated Radiative Transfer Code for Self-consistent Exoplanetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Malik, Matej; Grosheintz, Luc; Mendonça, João M.; Grimm, Simon L.; Lavie, Baptiste; Kitzmann, Daniel; Tsai, Shang-Min; Burrows, Adam; Kreidberg, Laura; Bedell, Megan; Bean, Jacob L.; Stevenson, Kevin B.; Heng, Kevin

    2017-02-01

    We present the open-source radiative transfer code named HELIOS, which is constructed for studying exoplanetary atmospheres. In its initial version, the model atmospheres of HELIOS are one-dimensional and plane-parallel, and the equation of radiative transfer is solved in the two-stream approximation with nonisotropic scattering. A small set of the main infrared absorbers is employed, computed with the opacity calculator HELIOS-K and combined using a correlated-k approximation. The molecular abundances originate from validated analytical formulae for equilibrium chemistry. We compare HELIOS with the work of Miller-Ricci & Fortney using a model of GJ 1214b, and perform several tests, where we find: model atmospheres with single-temperature layers struggle to converge to radiative equilibrium; k-distribution tables constructed with ≳ 0.01 cm‑1 resolution in the opacity function (≲ {10}3 points per wavenumber bin) may result in errors ≳ 1%–10% in the synthetic spectra; and a diffusivity factor of 2 approximates well the exact radiative transfer solution in the limit of pure absorption. We construct “null-hypothesis” models (chemical equilibrium, radiative equilibrium, and solar elemental abundances) for six hot Jupiters. We find that the dayside emission spectra of HD 189733b and WASP-43b are consistent with the null hypothesis, while the latter consistently underpredicts the observed fluxes of WASP-8b, WASP-12b, WASP-14b, and WASP-33b. We demonstrate that our results are somewhat insensitive to the choice of stellar models (blackbody, Kurucz, or PHOENIX) and metallicity, but are strongly affected by higher carbon-to-oxygen ratios. The code is publicly available as part of the Exoclimes Simulation Platform (exoclime.net).

  13. Accelerating a 3D finite-difference wave propagation code by a factor of 50 and a spectral-element code by a factor of 25 using a cluster of GPU graphics cards

    NASA Astrophysics Data System (ADS)

    Komatitsch, Dimitri; Michéa, David; Erlebacher, Gordon; Göddeke, Dominik

    2010-05-01

    We first accelerate a three-dimensional finite-difference in the time domain (FDTD) wave propagation code by a factor of about 50 using Graphics Processing Unit (GPU) computing on a cheap NVIDIA graphics card with the CUDA programming language. We implement the code in CUDA in the case of the fully heterogeneous elastic wave equation. We also implement Convolution Perfectly Matched Layers (CPMLs) on the graphics card to efficiently absorb outgoing waves on the fictitious edges of the grid. We show that the code that runs on the graphics card gives the expected results by comparing our results to those obtained by running the same simulation on a classical processor core. The methodology that we present can be used for Maxwell's equations as well because their form is similar to that of the seismic wave equation written in velocity vector and stress tensor. We then implement a high-order finite-element (spectral-element) application, which performs the numerical simulation of seismic wave propagation resulting for instance from earthquakes at the scale of a continent or from active seismic acquisition experiments in the oil industry, on a cluster of NVIDIA Tesla graphics cards using the CUDA programming language and non blocking message passing based on MPI. We compare it to the implementation in C language and MPI on a classical cluster of CPU nodes. We use mesh coloring to efficiently handle summation operations over degrees of freedom on an unstructured mesh, and we exchange information between nodes using non blocking MPI messages. Using non-blocking communications allows us to overlap the communications across the network and the data transfer between the GPU card and the CPU node on which it is installed with calculations on that GPU card. We perform a number of numerical tests to validate the single-precision CUDA and MPI implementation and assess its accuracy. We then analyze performance measurements and in average we obtain a speedup of 20x to 25x.

  14. Effect of physical training in cool and hot environments on +Gz acceleration tolerance in women

    NASA Technical Reports Server (NTRS)

    Brock, P. J.; Sciaraffa, D.; Greenleaf, J. E.

    1982-01-01

    Acceleration tolerance, plasma volume, and maximal oxygen uptake were measured in 15 healthy women before and after submaximal isotonic exercise training periods in cool and hot environments. The women were divided on the basis of age, maximal oxygen uptake, and +Gz tolerance into three groups: a group that exercised in heat (40.6 C), a group that exercised at a lower temperature (18.7 C), and a sedentary control group that functioned in the cool environment. There was no significant change in the +Gz tolerance in any group after training, and terminal heart rates were similar within each group. It is concluded that induction of moderate acclimation responses without increases in sweat rate or resting plasma volume has no influence on +Gz acceleration tolerance in women.

  15. Plasma physics. Stochastic electron acceleration during spontaneous turbulent reconnection in a strong shock wave.

    PubMed

    Matsumoto, Y; Amano, T; Kato, T N; Hoshino, M

    2015-02-27

    Explosive phenomena such as supernova remnant shocks and solar flares have demonstrated evidence for the production of relativistic particles. Interest has therefore been renewed in collisionless shock waves and magnetic reconnection as a means to achieve such energies. Although ions can be energized during such phenomena, the relativistic energy of the electrons remains a puzzle for theory. We present supercomputer simulations showing that efficient electron energization can occur during turbulent magnetic reconnection arising from a strong collisionless shock. Upstream electrons undergo first-order Fermi acceleration by colliding with reconnection jets and magnetic islands, giving rise to a nonthermal relativistic population downstream. These results shed new light on magnetic reconnection as an agent of energy dissipation and particle acceleration in strong shock waves.

  16. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    DOE PAGES

    Stygar, W. A.; Awe, T. J.; Bennett, N L; ...

    2015-11-30

    Here, we have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated bymore » the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator’s water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator’s physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD

  17. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    SciTech Connect

    Stygar, W. A.; Awe, T. J.; Bennett, N L; Breden, E. W.; Campbell, E. M.; Clark, R. E.; Cooper, R. A.; Cuneo, M. E.; Ennis, J. B.; Fehl, D. L.; Genoni, T. C.; Gomez, M. R.; Greiser, G. W.; Gruner, F. R.; Herrmann, M. C.; Hutsel, B. T.; Jennings, C. A.; Jobe, D. O.; Jones, B. M.; Jones, M. C.; Jones, P. A.; Knapp, P. F.; Lash, J. S.; LeChien, K. R.; Leckbee, J. J.; Leeper, R. J.; Lewis, S. A.; Long, F. W.; Lucero, D. J.; Madrid, E. A.; Martin, M. R.; Matzen, M. K.; Mazarakis, M. G.; McBride, R. D.; McKee, G. R.; Miller, C. L.; Moore, J. K.; Mostrom, C. B.; Mulville, T. D.; Peterson, K. J.; Porter, J. L.; Reisman, D. B.; Rochau, G. A.; Rochau, G. E.; Rose, D. V.; Savage, M. E.; Sceiford, M. E.; Schmit, P. F.; Schneider, R. F.; Schwarz, J.; Sefkow, A. B.; Sinars, D. B.; Slutz, S. A.; Spielman, R. B.; Stoltzfus, B. S.; Thoma, C.; Vesey, R. A.; Wakeland, P. E.; Welch, D. R.; Wisher, M. L.; Woodworth, J. R.; Bailey, J. E.; Rovang, D. C.

    2015-11-30

    Here, we have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated by the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator’s water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator’s physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD

  18. Nuclear physics information needed for accelerator driven transmutation of nuclear waste

    SciTech Connect

    Lisowski, P.W.; Bowman, C.D.; Arthur, E.D.; Young, P.G.

    1991-01-01

    There is renewed interest in using accelerator driven neutron sources to address the problem of high-level long-lived nuclear waste. Several laboratories have developed systems that may have a significant impact on the future use of nuclear power, adding options for dealing with long-lived actinide wastes and fission products, and for power production. This paper describes a new Los Alamos concept using thermal neutrons and examines the nuclear data requirements. 7 refs., 3 figs., 1 tab.

  19. From Physics Model to Results: An Optimizing Framework for Cross-Architecture Code Generation

    DOE PAGES

    Blazewicz, Marek; Hinder, Ian; Koppelman, David M.; ...

    2013-01-01

    Starting from a high-level problem description in terms of partial differential equations using abstract tensor notation, the Chemora framework discretizes, optimizes, and generates complete high performance codes for a wide range of compute architectures. Chemora extends the capabilities of Cactus, facilitating the usage of large-scale CPU/GPU systems in an efficient manner for complex applications, without low-level code tuning. Chemora achieves parallelism through MPI and multi-threading, combining OpenMP and CUDA. Optimizations include high-level code transformations, efficient loop traversal strategies, dynamically selected data and instruction cache usage strategies, and JIT compilation of GPU code tailored to the problem characteristics. The discretizationmore » is based on higher-order finite differences on multi-block domains. Chemora's capabilities are demonstrated by simulations of black hole collisions. This problem provides an acid test of the framework, as the Einstein equations contain hundreds of variables and thousands of terms.« less

  20. "Friluftsliv": A Contribution to Equity and Democracy in Swedish Physical Education? An Analysis of Codes in Swedish Physical Education Curricula

    ERIC Educational Resources Information Center

    Backman, Erik

    2011-01-01

    During the last decade, expanding research investigating the school subject Physical Education (PE) indicates a promotion of inequalities regarding which children benefit from PE teaching. Outdoor education and its Scandinavian equivalent "friluftsliv," is a part of the PE curriculum in many countries, and these practices have been…

  1. First experience with particle-in-cell plasma physics code on ARM-based HPC systems

    NASA Astrophysics Data System (ADS)

    Sáez, Xavier; Soba, Alejandro; Sánchez, Edilberto; Mantsinen, Mervi; Mateo, Sergi; Cela, José M.; Castejón, Francisco

    2015-09-01

    In this work, we will explore the feasibility of porting a Particle-in-cell code (EUTERPE) to an ARM multi-core platform from the Mont-Blanc project. The used prototype is based on a system-on-chip Samsung Exynos 5 with an integrated GPU. It is the first prototype that could be used for High-Performance Computing (HPC), since it supports double precision and parallel programming languages.

  2. The High-Luminosity upgrade of the LHC: Physics and Technology Challenges for the Accelerator and the Experiments

    NASA Astrophysics Data System (ADS)

    Schmidt, Burkhard

    2016-04-01

    In the second phase of the LHC physics program, the accelerator will provide an additional integrated luminosity of about 2500/fb over 10 years of operation to the general purpose detectors ATLAS and CMS. This will substantially enlarge the mass reach in the search for new particles and will also greatly extend the potential to study the properties of the Higgs boson discovered at the LHC in 2012. In order to meet the experimental challenges of unprecedented pp luminosity, the experiments will need to address the aging of the present detectors and to improve the ability to isolate and precisely measure the products of the most interesting collisions. The lectures gave an overview of the physics motivation and described the conceptual designs and the expected performance of the upgrades of the four major experiments, ALICE, ATLAS, CMS and LHCb, along with the plans to develop the appropriate experimental techniques and a brief overview of the accelerator upgrade. Only some key points of the upgrade program of the four major experiments are discussed in this report; more information can be found in the references given at the end.

  3. Hadron Physics at the Charm and Bottom Thresholds and Other Novel QCD Physics Topics at the NICA Accelerator Facility

    SciTech Connect

    Brodsky, Stanley J.; /SLAC

    2012-06-20

    The NICA collider project at the Joint Institute for Nuclear Research in Dubna will have the capability of colliding protons, polarized deuterons, and nuclei at an effective nucleon-nucleon center-of mass energy in the range {radical}s{sub NN} = 4 to 11 GeV. I briefly survey a number of novel hadron physics processes which can be investigated at the NICA collider. The topics include the formation of exotic heavy quark resonances near the charm and bottom thresholds, intrinsic strangeness, charm, and bottom phenomena, hidden-color degrees of freedom in nuclei, color transparency, single-spin asymmetries, the RHIC baryon anomaly, and non-universal antishadowing.

  4. Health physics aspects of neutron activated components in a linear accelerator.

    PubMed

    Guo, Shuntong; Ziemer, Paul L

    2004-05-01

    The purpose of this study was to investigate the residual radioactivity in the therapy accessories of a medical x ray linear accelerator. The residual radioactivity mainly originated from nuclear activation reactions by neutrons, which are present as a contamination radiation in the x-ray beam. The radiation used in this study was the 25 MV x-ray beam produced by a CGR Saturne III linear accelerator. The five treatment aids include four wedges of various angles and one cerrobend block. The decrease in dose rates with time was followed for 60 min for each of the five treatment aids immediately after 999 monitor units of irradiation. The integral doses from the surface of each of four activated therapy accessories following three different radiation doses were measured by using thermoluminescent dosimeters (CaF2). In the TLD measurement, polyethylene filters were used to differentiate beta or beta particles from the mixed decay radiation. A high-purity germanium detection system was utilized to collect and to analyze the gamma spectra from the activated therapy accessories. The residual radioisotopes found in the 15 degree wedge and 30 degree wedge included V, Cr, Cr, Mn, Fe, Co, and Ni. In the 45 degree and 60 degree wedges, the radionuclides identified were Co, Ni, Cu, and W. The principal nuclides identified in the irradiated cerrobend block were In, Sn, Cd, Pb. The corresponding nuclear reactions from which the residual radionuclides produced were confirmed by consulting the current literature.

  5. Health Physics Aspects of Neutron Activated Components in a Linear Accelerator.

    PubMed

    Guo, Shuntong; Ziemer, Paul L

    2004-05-01

    The purpose of this study was to investigate the residual radioactivity in the therapy accessories of a medical x ray linear accelerator. The residual radioactivity mainly originated from nuclear activation reactions by neutrons, which are present as a contamination radiation in the x-ray beam. The radiation used in this study was the 25 MV x-ray beam produced by a CGR Saturne III linear accelerator. The five treatment aids include four wedges of various angles and one cerrobend block. The decrease in dose rates with time was followed for 60 min for each of the five treatment aids immediately after 999 monitor units of irradiation. The integral doses from the surface of each of four activated therapy accessories following three different radiation doses were measured by using thermoluminescent dosimeters (CaF2). In the TLD measurement, polyethylene filters were used to differentiate β or β particles from the mixed decay radiation. A high-purity germanium detection system was utilized to collect and to analyze the γ spectra from the activated therapy accessories. The residual radioisotopes found in the 15° wedge and 30° wedge included V, Cr, Cr, Mn, Fe, Co, and Ni. In the 45° and 60° wedges, the radionuclides identified were Co, Ni, Cu, and W. The principal nuclides identified in the irradiated cerrobend block were In, Sn, Cd, Pb. The corresponding nuclear reactions from which the residual radionuclides produced were confirmed by consulting the current literature.

  6. Extreme of Landscape in Nuclear Physics via High Power Accelerators and Innovative Instrumentation

    NASA Astrophysics Data System (ADS)

    Gales, S.

    2013-06-01

    The advent of high power light and heavy ion accelerators producing intense secondary radioactive ion beams (RIB) made possible the exploration of a new territory of nuclei with extreme in Mass and/or N/Z ratios. To pursue the investigation of this "terra incognita" several projects, based on second generation accelerators producing intense stables and RIB, all aiming at the increase by several orders of magnitude of the RIB intensities are now under construction and/or planned for the end of this decade in the world. RIB production at SPES@Legnaro, SPIRAL2@GANIL, ALTO@Orsay, ISAC@TRIUMPF and HIE-ISOLDE@CERN are based on the ISOL method, RIBF@RIKEN, FRIB@MSU-NSCL, FAIR@GSI with the new Super-FRS fragment - separator takes advantage of the "In Flight" technique. Projects of high intensity heavy ions, and low energy drivers (< 10 MeV/n) are also foreseen at Flerov Laboratory@DUBNA, GSI, RIKEN and GANIL. Technical performances, innovative new instrumentation and methods, and keys experiments in connection with these second generation high intensity facilities will be reviewed.

  7. Accelerated fatigue behavior and mechano-physical characterizations of in vitro physiological simulation of nitinol stents.

    PubMed

    Saidane, K; Polizu, S; Yahia, L'h

    2007-01-01

    In this study, we have provided an experimental evaluation of the fatigue behavior of the nitinol (NiTi) endovascular device (peripheral stent). The accelerated fatigue tests were performed using arterial conditions, which mimicked actual physiological conditions. Natural, rubber latex-tubing materials were used to simulate human arteries. The equipment design and the test parameters used allowed for the simulation of a compliant artery and the application of circumferential forces to the device.The stent compliance values were good indicators for tracking the time evolution of fatigue behavior. Moreover, the analyses of changes on the surface morphology and on the chemical composition were used to establish a relationship between surface characteristics and peripheral stent response during 400 million cycles, which is equivalent to 10 yrs of human life. In order to determine the influence of the accelerated fatigue, an evaluation of both mechanical and surface characteristics was carried out before and after testing using the following tests and methods, respectively: radial hoop testing (RH), scanning electron microscope analysis (SEM), auger electron spectroscopy (AES), atomic absorption spectroscopy (AAS), and X-ray photoelectron spectroscopy (XPS). Under these experimental conditions, the studies have shown that after 400 million cycles, the tested stents did not demonstrate any mechanical failure. Moreover, the surface did not undergo any changes in its chemical composition. However, we did observe an increase in roughness and signs of pitting corrosion.

  8. Commnity Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect

    Spentzouris, Panagiotis; Cary, John; Mcinnes, Lois Curfman; Mori, Warren; Ng, Cho; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2008-07-01

    The design and performance optimization of particle accelerators is essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC1 Accelerator Science and Technology project, the SciDAC2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modeling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multi-physics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  9. Montecarlo simulation code in optimisation of the IntraOperative Radiation Therapy treatment with mobile dedicated accelerator

    NASA Astrophysics Data System (ADS)

    Catalano, M.; Agosteo, S.; Moretti, R.; Andreoli, S.

    2007-06-01

    The principle of optimisation of the EURATOM 97/43 directive foresees that for all medical exposure of individuals for radiotherapeutic purposes, exposures of target volumes shall be individually planned, taking into account that doses of non-target volumes and tissues shall be as low as reasonably achievable and consistent with the intended radiotherapeutic purpose of the exposure. Treatment optimisation has to be carried out especially in non conventional radiotherapic procedures, as Intra Operative Radiation Therapy (IORT) with mobile dedicated LINear ACcelerator (LINAC), which does not make use of a Treatment Planning System. IORT is carried out with electron beams and refers to the application of radiation during a surgical intervention, after the removal of a neoplastic mass and it can also be used as a one-time/stand alone treatment in initial cancer of small volume. IORT foresees a single session and a single beam only; therefore it is necessary to use protection systems (disks) temporary positioned between the target volume and the underlying tissues, along the beam axis. A single high Z shielding disk is used to stop the electrons of the beam at a certain depth and protect the tissues located below. Electron back scatter produces an enhancement in the dose above the disk, and this can be reduced if a second low Z disk is placed above the first. Therefore two protection disks are used in clinical application. On the other hand the dose enhancement at the interface of the high Z disk and the target, due to back scattering radiation, can be usefully used to improve the uniformity in treatment of thicker target volumes. Furthermore the dose above the disks of different Z material has to be evaluated in order to study the optimal combination of shielding disks that allow both to protect the underlying tissues and to obtain the most uniform dose distribution in target volumes of different thicknesses. The dose enhancement can be evaluated using the electron

  10. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  11. Introduction to high-energy physics and the Stanford Linear Accelerator Center (SLAC)

    SciTech Connect

    Clearwater, S.

    1983-03-01

    The type of research done at SLAC is called High Energy Physics, or Particle Physics. This is basic research in the study of fundamental particles and their interactions. Basic research is research for the sake of learning something. Any practical application cannot be predicted, the understanding is the end in itself. Interactions are how particles behave toward one another, for example some particles attract one another while others repel and still others ignore each other. Interactions of elementary particles are studied to reveal the underlying structure of the universe.

  12. Noncoherent Physical-Layer Network Coding with FSK Modulation: Relay Receiver Design Issues

    DTIC Science & Technology

    2011-03-01

    digital network coding ( DNC ) to distinguish it from ANC. Under 0090-6778/11$25.00 c⃝ 2011 IEEE Report Documentation Page Form ApprovedOMB No. 0704-0188...223 2596 IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 59, NO. 9, SEPTEMBER 2011 many channel conditions, DNC offers enhanced performance over ANC. This...is because the decoding operation at the relay helps DNC to remove noise from the MAC phase, while the noise is amplied by the relay when ANC is used

  13. Development Status of the PEBBLES Code for Pebble Mechanics: Improved Physical Models and Speed-up

    SciTech Connect

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2009-09-01

    PEBBLES is a code for simulating the motion of all the pebbles in a pebble bed reactor. Since pebble bed reactors are packed randomly and not precisely placed, the location of the fuel elements in the reactor is not deterministically known. Instead, when determining operating parameters the motion of the pebbles can be simulated and stochastic locations can be found. The PEBBLES code can output information relevant for other simulations of the pebble bed reactors such as the positions of the pebbles in the reactor, packing fraction change in an earthquake, and velocity profiles created by recirculation. The goal for this level three milestone was to speedup the PEBBLES code through implementation on massively parallel computer. Work on this goal has resulted in speeding up both the single processor version and creation of a new parallel version of PEBBLES. Both the single processor version and the parallel running capability of the PEBBLES code have improved since the fiscal year start. The hybrid MPI/OpenMP PEBBLES version was created this year to run on the increasingly common cluster hardware profile that combines nodes with multiple processors that share memory and a cluster of nodes that are networked together. The OpenMP portions use the Open Multi-Processing shared memory parallel processing model to split the task across processors in a single node that shares memory. The Message Passing Interface (MPI) portion uses messages to communicate between different nodes over a network. The following are wall clock speed up for simulating an NGNP-600 sized reactor. The single processor version runs 1.5 times faster compared to the single processor version at the beginning of the fiscal year. This speedup is primarily due to the improved static friction model described in the report. When running on 64 processors, the new MPI/OpenMP hybrid version has a wall clock speed up of 22 times compared to the current single processor version. When using 88 processors, a

  14. Development Status of the PEBBLES Code for Pebble Mechanics: Improved Physical Models and Speed-up

    SciTech Connect

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2009-12-01

    PEBBLES is a code for simulating the motion of all the pebbles in a pebble bed reactor. Since pebble bed reactors are packed randomly and not precisely placed, the location of the fuel elements in the reactor is not deterministically known. Instead, when determining operating parameters the motion of the pebbles can be simulated and stochastic locations can be found. The PEBBLES code can output information relevant for other simulations of the pebble bed reactors such as the positions of the pebbles in the reactor, packing fraction change in an earthquake, and velocity profiles created by recirculation. The goal for this level three milestone was to speedup the PEBBLES code through implementation on massively parallel computer. Work on this goal has resulted in speeding up both the single processor version and creation of a new parallel version of PEBBLES. Both the single processor version and the parallel running capability of the PEBBLES code have improved since the fiscal year start. The hybrid MPI/OpenMP PEBBLES version was created this year to run on the increasingly common cluster hardware profile that combines nodes with multiple processors that share memory and a cluster of nodes that are networked together. The OpenMP portions use the Open Multi-Processing shared memory parallel processing model to split the task across processors in a single node that shares memory. The Message Passing Interface (MPI) portion uses messages to communicate between different nodes over a network. The following are wall clock speed up for simulating an NGNP-600 sized reactor. The single processor version runs 1.5 times faster compared to the single processor version at the beginning of the fiscal year. This speedup is primarily due to the improved static friction model described in the report. When running on 64 processors, the new MPI/OpenMP hybrid version has a wall clock speed up of 22 times compared to the current single processor version. When using 88 processors, a

  15. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    PubMed

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.

  16. Accelerated Integrated Science Sequence (AISS): An Introductory Biology, Chemistry, and Physics Course

    ERIC Educational Resources Information Center

    Purvis-Roberts, Kathleen L.; Edwalds-Gilbert, Gretchen; Landsberg, Adam S.; Copp, Newton; Ulsh, Lisa; Drew, David E.

    2009-01-01

    A new interdisciplinary, introductory science course was offered for the first time during the 2007-2008 school year. The purpose of the course is to introduce students to the idea of working at the intersections of biology, chemistry, and physics and to recognize interconnections between the disciplines. Interdisciplinary laboratories are a key…

  17. [Simulation of alpha-helix and beta-hairpin formation in water-soluble proteins by the code physics method].

    PubMed

    Shestopalov, B V

    2007-01-01

    One of the possible ways for complete and final solution of the problem of determination of three-dimensional structure of proteins on amino acid sequence is simulation of protein three-dimensional structure formation. The use of the code physics method developed by the author has been suggested to fulfill this task. The simulation of alpha-helix and beta-hairpin formation in water-soluble proteins as a start of realization of the plan is described here. The results of the simulation were compared with the experimental data for 14 proteins of no more than 50 amino acids and therefore with little number of alpha-helices and beta-strands (to meet limits of simulation process) and with secondary structure predictions by the best to data methods of protein secondary structure prediction, PSIpred, PORTER and PROFsec. Secondary structure of the proteins, obtained as a result of the simulation of alpha-helix and beta-hairpin formation using the code physics method, corresponded completely to experimental data while the secondary structure predicted by the PSIpred, PORTER and PROFsec methods differed from these data significantly.

  18. Accelerating translation of physical activity and cancer survivorship research into practice: recommendations for a more integrated and collaborative approach.

    PubMed

    Phillips, Siobhan M; Alfano, Catherine M; Perna, Frank M; Glasgow, Russell E

    2014-05-01

    Physical activity has been deemed safe and effective in reducing many negative side effects of treatment for cancer survivors and promoting better overall health. However, most of this research has focused on highly controlled randomized trials and little of this research has been translated into care or policy for survivors. The purpose of the present article is to present a research agenda for the field to accelerate the dissemination and implementation of empirically supported physical activity interventions into care. We provide rationale for the role of basic, behavioral, clinical implementation, and population scientists in moving this science forward and call for a more coordinated effort across different phases of research. In addition, we provide key strategies and examples for ongoing and future studies using the RE-AIM (reach, efficacy/effectiveness, adoption, implementation, and maintenance) framework and pose recommendations for collaborations between researchers and stakeholders to enhance the integration of this research into policy and practice. Overall, we recommend that physical activity and cancer survivorship research use additional study designs, include relevant stakeholders, and be more collaborative, integrated, contextual, and representative in terms of both setting and participants.

  19. Basic physical and chemical information needed for development of Monte Carlo codes

    SciTech Connect

    Inokuti, M.

    1993-08-01

    It is important to view track structure analysis as an application of a branch of theoretical physics (i.e., statistical physics and physical kinetics in the language of the Landau school). Monte Carlo methods and transport equation methods represent two major approaches. In either approach, it is of paramount importance to use as input the cross section data that best represent the elementary microscopic processes. Transport analysis based on unrealistic input data must be viewed with caution, because results can be misleading. Work toward establishing the cross section data, which demands a wide scope of knowledge and expertise, is being carried out through extensive international collaborations. In track structure analysis for radiation biology, the need for cross sections for the interactions of electrons with DNA and neighboring protein molecules seems to be especially urgent. Finally, it is important to interpret results of Monte Carlo calculations fully and adequately. To this end, workers should document input data as thoroughly as possible and report their results in detail in many ways. Workers in analytic transport theory are then likely to contribute to the interpretation of the results.

  20. Reactor physics studies for the Advanced Fuel Cycle Initiative (AFCI) Reactor-Accelerator Coupling Experiments (RACE) Project

    NASA Astrophysics Data System (ADS)

    Stankovskiy, Evgeny Yuryevich

    In the recently completed RACE Project of the AFCI, accelerator-driven subcritical systems (ADS) experiments were conducted to develop technology of coupling accelerators to nuclear reactors. In these experiments electron accelerators induced photon-neutron reactions in heavy-metal targets to initiate fission reactions in ADS. Although the Idaho State University (ISU) RACE ADS was constructed only to develop measurement techniques for advanced experiments, many reactor kinetics experiments were conducted there. In the research reported in this dissertation, a method was developed to calculate kinetics parameters for measurement and calculation of the reactivity of ADS, a safety parameter that is necessary for control and monitoring of power production. Reactivity is measured in units of fraction of delayed versus prompt neutron from fission, a quantity that cannot be directly measured in far-subcritical reactors such as the ISU RACE configuration. A new technique is reported herein to calculate it accurately and to predict kinetic behavior of a far-subcritical ADS. Experiments conducted at ISU are first described and experimental data are presented before development of the kinetic theory used in the new computational method. Because of the complexity of the ISU ADS, the Monte-Carlo method as applied in the MCNP code is most suitable for modeling reactor kinetics. However, the standard method of calculating the delayed neutron fraction produces inaccurate values. A new method was developed and used herein to evaluate actual experiments. An advantage of this method is that its efficiency is independent of the fission yield of delayed neutrons, which makes it suitable for fuel with a minor actinide component (e.g. transmutation fuels). The implementation of this method is based on a correlated sampling technique which allows the accurate evaluation of delayed and prompt neutrons. The validity of the obtained results is indicated by good agreement between experimental

  1. THE RHIC INJECTOR ACCELERATORS CONFIGURATIONS, AND PERFORMANCE FOR THE RHIC 2003 AU - D PHYSICS RUN.

    SciTech Connect

    Ahrens, L; Benjamin, J; Blaskiewicz, M; Brennan, J M; Brown, K A; Carlson, K A; Delong, J; D'Ottavio, T; Frak, B; Gardner, C J; Glenn, J W; Harvey, M; Hayes, T; Hseuh, H- C; Ingrassia, P; Lowenstein, D; Mackay, W; Marr, G; Morris, J; Roser, T; Satogata, T; Smith, G; Smith, K S; Steski, D; Tsoupas, N; Thieberger, P; Zeno, K; Zhang, S Y

    2003-05-12

    The RHIC 2003 Physics Run [1] required collisions between gold ions and deuterons. The injector necessarily had to deliver adequate quality (transverse and longitudinal emittance) and quantity of both species. For gold this was a continuing evolution from past work [2]. For deuterons it was new territory. For the filling of the RHIC the injector not only had to deliver quality beams but also had to switch between these species quickly. This paper details the collider requirements and our success in meeting these. Some details of the configurations employed are given.

  2. The Development of Biomedical Applications of Nuclear Physics Detector Technology at the Thomas Jefferson National Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Weisenberger, Andrew

    2003-10-01

    The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility (Jefferson Lab) for the United States Department of Energy. As a user facility for physicists worldwide, its primary mission is to conduct basic nuclear physics research of the atom's nucleus at the quark level. Within the Jefferson Lab Physics Division is the Jefferson Lab Detector Group which was formed to support the design and construction of new detector systems during the construction phase of the major detector systems at Jefferson Lab and to act as technical consultants for the lab scientists and users. The Jefferson Lab Detector Group, headed by Dr. Stan Majewski, has technical capabilities in the development and use of radiation detection systems. These capabilities include expertise in nuclear particle detection through the use of gas detectors, scintillation and light guide techniques, standard and position-sensitive photomultiplier tubes (PSPMTs), fast analog readout electronics and data acquisition, and on-line image formation and analysis. In addition to providing nuclear particle detector support to the lab, the group has for several years (starting in 1996) applied these technologies to the development of novel high resolution gamma-ray imaging systems for biomedical applications and x-ray imaging techniques. The Detector Group has developed detector systems for breast cancer detection, brain cancer therapy and small animal imaging to support biomedical research. An overview will be presented of how this small nuclear physics detector research group by teaming with universities, medical facilities, industry and other national laboratories applies technology originating from basic nuclear physics research to biomedical applications.

  3. Physics of the Dayside Magnetosphere: New Results From a Hybrid Kinetic Code

    NASA Technical Reports Server (NTRS)

    Siebeck, D. G.; Omidi, N.

    2007-01-01

    We use a global hybrid code kinetic model to demonstrate how kinetic processes at the bow shock and within the foreshock can dramatically modify the solar wind just before its interaction with the magnetosphere. During periods of steady radial interplanetary magnetic field (IMF) orientation, the foreshock fills with a diffuse population of suprathermal ions. The ions generate cavities marked by enhanced temperatures, depressed densities, and diminished magnetic field strengths that convect antisunward into the bow shock with the solar wind flow. Tangential discontinuities marked by inward-pointing electric fields and normals transverse to the Sun-Earth line generate hot flow anomalies marked by hot tenuous plasmas bounded by outward propagating shocks. When the motional electric field in the magnetosheath points inward towards the Earth, a solitary bow shock appears. For typical IMF orientations, the solitary shocks should appear at poorly sampled high latitudes, but for strongly northward or southward IMF orientations the solitary shocks should appear on the flanks of the magnetosphere. Although quasi-perpendicular, solitary shocks should be marked by turbulent magnetosheath flows, often directed towards the Sun-Earth line, and abrupt spike-like enhancements in the density and magnetic field strength at the shock. Finally,we show how flux transfer events generated between parallel subsolar reconnection lines are destroyed upon encountering the magnetopause at latitudes above the cusp.

  4. New laser driver for physics modeling codes using unstructured 3d grids

    SciTech Connect

    Kaiser, T; Milovich, J L; Prasad, M K; Shestakov, A I

    1999-02-01

    We present a status report on the current state of development, testing and application of a new scheme for laser beam evolution and power deposition on three-dimensional unstructured grids. The scheme is being encapsulated in a C++ library for convenient porting to existing modeling codes. We have added a new ray propagator that is second order in time, allowing rays to refract within computational zones as well as at zone interfaces. In a globally constant free-electron density gradient on a randomized hexahedral mesh,the new integrator produces ray trajectories that agree with analytic results to within machine roundoff. A new method for computing the inverse-bremmstrahlung energy deposition rate that captures its highly non-uniform spatial dependence within a zone has also been added. This allows accurate trajectories without the necessity of sub-stepping in time. Other enhancements (not discussed) include multiple user-configurable beams, computation of the electron oscillation velocity in the laser electric field and energy-deposition accounting. Results of laser-driven simulations are presented in a companion paper.

  5. Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

    SciTech Connect

    Spentzouris, Panagiotis; Cary, John; Mcinnes, Lois Curfman; Mori, Warren; Ng, Cho; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2011-10-21

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  6. 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.

  7. PHYSICS OF OUR DAYS Physical conditions in potential accelerators of ultra-high-energy cosmic rays: updated Hillas plot and radiation-loss constraints

    NASA Astrophysics Data System (ADS)

    Ptitsyna, Kseniya V.; Troitsky, Sergei V.

    2010-10-01

    We review basic constraints on the acceleration of ultra-high-energy (UHE) cosmic rays (CRs) in astrophysical sources, namely, the geometric (Hillas) criterion and the restrictions from radiation losses in different acceleration regimes. Using the latest available astrophysical data, we redraw the Hillas plot and find potential UHECR accelerators. For the acceleration in the central engines of active galactic nuclei, we constrain the maximal UHECR energy for a given black hole mass. Among active galaxies, only the most powerful ones, radio galaxies and blazars, are able to accelerate protons to UHE, although acceleration of heavier nuclei is possible in much more abundant lower-power Seyfert galaxies.

  8. The Rosslyn Code: Can Physics Explain a 500-Year Old Melody Etched in the Walls of a Scottish Chapel?

    SciTech Connect

    Wilson, Chris

    2011-10-19

    For centuries, historians have puzzled over a series of 213 symbols carved into the stone of Scotland’s Rosslyn Chapel. (Disclaimer: You may recognize this chapel from The Da Vinci Code, but this is real and unrelated!) Several years ago, a composer and science enthusiast noticed that the symbols bore a striking similarity to Chladni patterns, the elegant images that form on a two- dimensional surface when it vibrates at certain frequencies. This man’s theory: A 500-year-old melody was inscribed in the chapel using the language of physics. But not everyone is convinced. Slate senior editor Chris Wilson travelled to Scotland to investigate the claims and listen to this mysterious melody, whatever it is. Come find out what he discovered, including images of the patterns and audio of the music they inspired.

  9. Reactivity effects in VVER-1000 of the third unit of the kalinin nuclear power plant at physical start-up. Computations in ShIPR intellectual code system with library of two-group cross sections generated by UNK code

    SciTech Connect

    Zizin, M. N.; Zimin, V. G.; Zizina, S. N. Kryakvin, L. V.; Pitilimov, V. A.; Tereshonok, V. A.

    2010-12-15

    The ShIPR intellectual code system for mathematical simulation of nuclear reactors includes a set of computing modules implementing the preparation of macro cross sections on the basis of the two-group library of neutron-physics cross sections obtained for the SKETCH-N nodal code. This library is created by using the UNK code for 3D diffusion computation of first VVER-1000 fuel loadings. Computation of neutron fields in the ShIPR system is performed using the DP3 code in the two-group diffusion approximation in 3D triangular geometry. The efficiency of all groups of control rods for the first fuel loading of the third unit of the Kalinin Nuclear Power Plant is computed. The temperature, barometric, and density effects of reactivity as well as the reactivity coefficient due to the concentration of boric acid in the reactor were computed additionally. Results of computations are compared with the experiment.

  10. Canted-Cosine-Theta Superconducting Accelerator Magnets for High Energy Physics and Ion Beam Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Brouwer, Lucas Nathan

    Advances in superconducting magnet technology have historically enabled the construction of new, higher energy hadron colliders. Looking forward to the needs of a potential future collider, a significant increase in magnet field and performance is required. Such a task requires an open mind to the investigation of new design concepts for high field magnets. Part I of this thesis will present an investigation of the Canted-Cosine-Theta (CCT) design for high field Nb3Sn magnets. New analytic and finite element methods for analysis of CCT magnets will be given, along with a discussion on optimization of the design for high field. The design, fabrication, and successful test of the 2.5 T NbTi dipole CCT1 will be presented as a proof-of-principle step towards a high field Nb3Sn magnet. Finally, the design and initial steps in the fabrication of the 16 T Nb3Sn dipole CCT2 will be described. Part II of this thesis will investigate the CCT concept extended to a curved magnet for use in an ion beam therapy gantry. The introduction of superconducting technology in this field shows promise to reduce the weight and cost of gantries, as well as open the door to new beam optics solutions with high energy acceptance. An analytic approach developed for modeling curved CCT magnets will be presented, followed by a design study of a superconducting magnet for a proton therapy gantry. Finally, a new magnet concept called the "Alternating Gradient CCT" (AG-CCT) will be introduced. This concept will be shown to be a practical magnet solution for achieving the alternating quadrupole fields desired for an achromatic gantry, allowing for the consideration of treatment with minimal field changes in the superconducting magnets. The primary motivation of this thesis is to share new developments for Canted-Cosine-Theta superconducting magnets, with the hope this design will improve technology for high energy physics and ion beam cancer therapy.

  11. Integration of the DRAGON5/DONJON5 codes in the SALOME platform for performing multi-physics calculations in nuclear engineering

    NASA Astrophysics Data System (ADS)

    Hébert, Alain

    2014-06-01

    We are presenting the computer science techniques involved in the integration of codes DRAGON5 and DONJON5 in the SALOME platform. This integration brings new capabilities in designing multi-physics computational schemes, with the possibility to couple our reactor physics codes with thermal-hydraulics or thermo-mechanics codes from other organizations. A demonstration is presented where two code components are coupled using the YACS module of SALOME, based on the CORBA protocol. The first component is a full-core 3D steady-state neuronic calculation in a PWR performed using DONJON5. The second component implement a set of 1D thermal-hydraulics calculations, each performed over a single assembly.

  12. Wind-US Code Physical Modeling Improvements to Complement Hypersonic Testing and Evaluation

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nicholas J.; Yoder, Dennis A.; Towne, Charles S.; Engblom, William A.; Bhagwandin, Vishal A.; Power, Greg D.; Lankford, Dennis W.; Nelson, Christopher C.

    2009-01-01

    This report gives an overview of physical modeling enhancements to the Wind-US flow solver which were made to improve the capabilities for simulation of hypersonic flows and the reliability of computations to complement hypersonic testing. The improvements include advanced turbulence models, a bypass transition model, a conjugate (or closely coupled to vehicle structure) conduction-convection heat transfer capability, and an upgraded high-speed combustion solver. A Mach 5 shock-wave boundary layer interaction problem is used to investigate the benefits of k- s and k-w based explicit algebraic stress turbulence models relative to linear two-equation models. The bypass transition model is validated using data from experiments for incompressible boundary layers and a Mach 7.9 cone flow. The conjugate heat transfer method is validated for a test case involving reacting H2-O2 rocket exhaust over cooled calorimeter panels. A dual-mode scramjet configuration is investigated using both a simplified 1-step kinetics mechanism and an 8-step mechanism. Additionally, variations in the turbulent Prandtl and Schmidt numbers are considered for this scramjet configuration.

  13. Proposed Physics Experiments for Laser-Driven Electron Linear Acceleration in a Dielectric Loaded Vacuum, Final Report

    SciTech Connect

    Byer, Robert L.

    2016-07-08

    This final report summarizes the last three years of research on the development of advanced linear electron accelerators that utilize dielectric wave-guide vacuum channels pumped by high energy laser fields to accelerate beams of electrons.

  14. Biological/biomedical accelerator mass spectrometry targets. 2. Physical, morphological, and structural characteristics.

    PubMed

    Kim, Seung-Hyun; Kelly, Peter B; Clifford, Andrew J

    2008-10-15

    The number of biological/biomedical applications that require AMS to achieve their goals is increasing, and so is the need for a better understanding of the physical, morphological, and structural traits of high quality of AMS targets. The metrics of quality included color, hardness/texture, and appearance (photo and SEM), along with FT-IR, Raman, and powder X-ray diffraction spectra that correlate positively with reliable and intense ion currents and accuracy, precision, and sensitivity of fraction modern ( F m). Our previous method produced AMS targets of gray-colored iron-carbon materials (ICM) 20% of the time and of graphite-coated iron (GCI) 80% of the time. The ICM was hard, its FT-IR spectra lacked the sp (2) bond, its Raman spectra had no detectable G' band at 2700 cm (-1), and it had more iron carbide (Fe 3C) crystal than nanocrystalline graphite or graphitizable carbon (g-C). ICM produced low and variable ion current whereas the opposite was true for the graphitic GCI. Our optimized method produced AMS targets of graphite-coated iron powder (GCIP) 100% of the time. The GCIP shared some of the same properties as GCI in that both were black in color, both produced robust ion current consistently, their FT-IR spectra had the sp (2) bond, their Raman spectra had matching D, G, G', D +G, and D '' bands, and their XRD spectra showed matching crystal size. GCIP was a powder that was easy to tamp into AMS target holders that also facilitated high throughput. We concluded that AMS targets of GCIP were a mix of graphitizable carbon and Fe 3C crystal, because none of their spectra, FT-IR, Raman, or XRD, matched exactly those of the graphite standard. Nevertheless, AMS targets of GCIP consistently produced the strong, reliable, and reproducible ion currents for high-throughput AMS analysis (270 targets per skilled analyst/day) along with accurate and precise F m values.

  15. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect

    Spentzouris, P.; Cary, J.; McInnes, L.C.; Mori, W.; Ng, C.; Ng, E.; Ryne, R.; /LBL, Berkeley

    2011-11-14

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization

  16. The Study of Advanced Accelerator Physics Research at UCLA Using the ATF at BNL: Vacuum Acceleration by Laser of Free Electrons

    SciTech Connect

    Cline, David B.

    2016-09-07

    An experiment was designed and data were taken to demonstrate that a tightly focused laser on vacuum can accelerate an electron beam in free space. The experiment was proof-of-principle and showed a clear effect for the laser beam off and on. The size of the effect was about 20% and was consistent over 30 laser and beam shots.

  17. Nonlinear Acceleration Methods for Even-Parity Neutron Transport

    SciTech Connect

    W. J. Martin; C. R. E. De Oliveira; H. Park

    2010-05-01

    Convergence acceleration methods for even-parity transport were developed that have the potential to speed up transport calculations and provide a natural avenue for an implicitly coupled multiphysics code. An investigation was performed into the acceleration properties of the introduction of a nonlinear quasi-diffusion-like tensor in linear and nonlinear solution schemes. Using the tensor reduced matrix as a preconditioner for the conjugate gradients method proves highly efficient and effective. The results for the linear and nonlinear case serve as the basis for further research into the application in a full three-dimensional spherical-harmonics even-parity transport code. Once moved into the nonlinear solution scheme, the implicit coupling of the convergence accelerated transport method into codes for other physics can be done seamlessly, providing an efficient, fully implicitly coupled multiphysics code with high order transport.

  18. GPU/MIC Acceleration of the LHC High Level Trigger to Extend the Physics Reach at the LHC

    SciTech Connect

    Halyo, Valerie; Tully, Christopher

    2015-04-14

    The quest for rare new physics phenomena leads the PI [3] to propose evaluation of coprocessors based on Graphics Processing Units (GPUs) and the Intel Many Integrated Core (MIC) architecture for integration into the trigger system at LHC. This will require development of a new massively parallel implementation of the well known Combinatorial Track Finder which uses the Kalman Filter to accelerate processing of data from the silicon pixel and microstrip detectors and reconstruct the trajectory of all charged particles down to momentums of 100 MeV. It is expected to run at least one order of magnitude faster than an equivalent algorithm on a quad core CPU for extreme pileup scenarios of 100 interactions per bunch crossing. The new tracking algorithms will be developed and optimized separately on the GPU and Intel MIC and then evaluated against each other for performance and power efficiency. The results will be used to project the cost of the proposed hardware architectures for the HLT server farm, taking into account the long term projections of the main vendors in the market (AMD, Intel, and NVIDIA) over the next 10 years. Extensive experience and familiarity of the PI with the LHC tracker and trigger requirements led to the development of a complementary tracking algorithm that is described in [arxiv: 1305.4855], [arxiv: 1309.6275] and preliminary results accepted to JINST.

  19. Acceleration of peripheral nerve regeneration through asymmetrically porous nerve guide conduit applied with biological/physical stimulation.

    PubMed

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa; Lee, Jin Ho

    2013-12-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NGC. The animal study revealed that each stimulation (NGF or US) has a positive effect to promote the peripheral nerve regeneration through the NGC, however, the US-stimulated NGC group allowed more accelerated nerve regeneration compared with the NGF-stimulated group. The NGC group that received dual stimulation (NGF and US) showed more effective nerve regeneration behavior than the groups that received a single stimulation (NGF or US). The asymmetrically porous NGC with dual NGF and US stimulation may be a promising strategy for the clinical treatment of delayed and insufficient functional recovery of a peripheral nerve.

  20. NASA low-speed centrifugal compressor for 3-D viscous code assessment and fundamental flow physics research

    NASA Technical Reports Server (NTRS)

    Hathaway, M. D.; Wood, J. R.; Wasserbauer, C. A.

    1991-01-01

    A low speed centrifugal compressor facility recently built by the NASA Lewis Research Center is described. The purpose of this facility is to obtain detailed flow field measurements for computational fluid dynamic code assessment and flow physics modeling in support of Army and NASA efforts to advance small gas turbine engine technology. The facility is heavily instrumented with pressure and temperature probes, both in the stationary and rotating frames of reference, and has provisions for flow visualization and laser velocimetry. The facility will accommodate rotational speeds to 2400 rpm and is rated at pressures to 1.25 atm. The initial compressor stage being tested is geometrically and dynamically representative of modern high-performance centrifugal compressor stages with the exception of Mach number levels. Preliminary experimental investigations of inlet and exit flow uniformly and measurement repeatability are presented. These results demonstrate the high quality of the data which may be expected from this facility. The significance of synergism between computational fluid dynamic analysis and experimentation throughout the development of the low speed centrifugal compressor facility is demonstrated.

  1. Langmuir probe-based observables for plasma-turbulence code validation and application to the TORPEX basic plasma physics experiment

    SciTech Connect

    Ricci, Paolo; Theiler, C.; Fasoli, A.; Furno, I.; Labit, B.; Mueller, S. H.; Podesta, M.; Poli, F. M.

    2009-05-15

    The methodology for plasma-turbulence code validation is discussed, with focus on the quantities to use for the simulation-experiment comparison, i.e., the validation observables, and application to the TORPEX basic plasma physics experiment [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)]. The considered validation observables are deduced from Langmuir probe measurements and are ordered into a primacy hierarchy, according to the number of model assumptions and to the combinations of measurements needed to form each of them. The lowest levels of the primacy hierarchy correspond to observables that require the lowest number of model assumptions and measurement combinations, such as the statistical and spectral properties of the ion saturation current time trace, while at the highest levels, quantities such as particle transport are considered. The comparison of the observables at the lowest levels in the hierarchy is more stringent than at the highest levels. Examples of the use of the proposed observables are applied to a specific TORPEX plasma configuration characterized by interchange-driven turbulence.

  2. Parallel Monte Carlo transport modeling in the context of a time-dependent, three-dimensional multi-physics code

    SciTech Connect

    Procassini, R.J.

    1997-12-31

    The fine-scale, multi-space resolution that is envisioned for accurate simulations of complex weapons systems in three spatial dimensions implies flop-rate and memory-storage requirements that will only be obtained in the near future through the use of parallel computational techniques. Since the Monte Carlo transport models in these simulations usually stress both of these computational resources, they are prime candidates for parallelization. The MONACO Monte Carlo transport package, which is currently under development at LLNL, will utilize two types of parallelism within the context of a multi-physics design code: decomposition of the spatial domain across processors (spatial parallelism) and distribution of particles in a given spatial subdomain across additional processors (particle parallelism). This implementation of the package will utilize explicit data communication between domains (message passing). Such a parallel implementation of a Monte Carlo transport model will result in non-deterministic communication patterns. The communication of particles between subdomains during a Monte Carlo time step may require a significant level of effort to achieve a high parallel efficiency.

  3. A 0.18 μm CMOS transmit physical coding sublayer IC for 100G Ethernet

    NASA Astrophysics Data System (ADS)

    Weihua, Ruan; Qingsheng, Hu

    2016-03-01

    This paper presents a transmit physical coding sublayer (PCS) circuit for 100G Ethernet. Based on the 4 × 25 Gb/s architecture according to the IEEE P802.3ba and IEEE P802.3bmTM/D1.1 standards, this PCS circuit is designed using a semi-custom design method and consists of 4 modules including 64B/66B encoder, scrambler, multiple lanes distribution and 66 : 8 gearbox. By using the pipeline structure and several optimization techniques, the working speed of the circuit is increased significantly. The parallel scrambling combined with logic optimization also improve the performance. In addition, a kind of phase-independent structure is employed in the design of the gearbox to ensure it can work stably and reliably at high frequency. This PCS circuit has been fabricated based on 0.18 μm CMOS technology and the total area is 1.7 × 1.7 mm2. Measured results show that the circuit can work properly at 100 Gb/s and the power consumption is about 284 mW with a 1.8 V supply. Project supported by the National Natural Science Foundation of China (No. 6504000129) and the National Basic Research Program of China (No. 6504000052).

  4. EDITORIAL: Laser and plasma accelerators Laser and plasma accelerators

    NASA Astrophysics Data System (ADS)

    Bingham, Robert

    2009-02-01

    as photon deceleration and acceleration and is the result of a modulational instability. Simulations reported by Trines et al using a photon-in-cell code or wave kinetic code agree extremely well with experimental observation. Ion acceleration is actively studied; for example the papers by Robinson, Macchi, Marita and Tripathi all discuss different types of acceleration mechanisms from direct laser acceleration, Coulombic explosion and double layers. Ion acceleration is an exciting development that may have great promise in oncology. The surprising application is in muon acceleration, demonstrated by Peano et al who show that counterpropagating laser beams with variable frequencies drive a beat structure with variable phase velocity, leading to particle trapping and acceleration with possible application to a future muon collider and neutrino factory. Laser and plasma accelerators remain one of the exciting areas of plasma physics with applications in many areas of science ranging from laser fusion, novel high-brightness radiation sources, particle physics and medicine. The guest editor would like to thank all authors and referees for their invaluable contributions to this special issue.

  5. The relation between tilt table and acceleration-tolerance and their dependence on stature and physical fitness

    NASA Technical Reports Server (NTRS)

    Klein, K. E.; Backhausen, F.; Bruner, H.; Eichhorn, J.; Jovy, D.; Schotte, J.; Vogt, L.; Wegman, H. M.

    1980-01-01

    A group of 12 highly trained athletes and a group of 12untrained students were subjected to passive changes of position on a tilt table and positive accelerations in a centrifuge. During a 20 min tilt, including two additional respiratory maneuvers, the number of faints and average cardiovascular responses did not differ significantly between the groups. During linear increase of acceleration, the average blackout level was almost identical in both groups. Statistically significant coefficients of product-moment correlation for various relations were obtained. The coefficient of multiple determination computed for the dependence of acceleration tolerance on heart-eye distance and systolic blood pressure at rest allows the explanation of almost 50% of the variation of acceleration tolerance. The maximum oxygen uptake showed the expected significant correlation to the heart rate at rest, but not the acceleration tolerance, or to the cardiovascular responses to tilting.

  6. Cardiac acceleration at the onset of exercise: a potential parameter for monitoring progress during physical training in sports and rehabilitation.

    PubMed

    Hettinga, Florentina J; Monden, Paul G; van Meeteren, Nico L U; Daanen, Hein A M

    2014-05-01

    There is a need for easy-to-use methods to assess training progress in sports and rehabilitation research. The present review investigated whether cardiac acceleration at the onset of physical exercise (HRonset) can be used as a monitoring variable. The digital databases of Scopus and PubMed were searched to retrieve studies investigating HRonset. In total 652 studies were retrieved. These articles were then classified as having emphasis on HRonset in a sports or rehabilitation setting, which resulted in 8 of 112 studies with a sports application and 6 of 68 studies with a rehabilitation application that met inclusion criteria. Two co-existing mechanisms underlie HRonset: feedforward (central command) and feedback (mechanoreflex, metaboreflex, baroreflex) control. A number of studies investigated HRonset during the first few seconds of exercise (HRonsetshort), in which central command and the mechanoreflex determine vagal withdrawal, the major mechanism by which heart rate (HR) increases. In subsequent sports and rehabilitation studies, interest focused on HRonset during dynamic exercise over a longer period of time (HRonsetlong). Central command, mechanoreflexes, baroreflexes, and possibly metaboreflexes contribute to HRonset during the first seconds and minutes of exercise, which in turn leads to further vagal withdrawal and an increase in sympathetic activity. HRonset has been described as the increase in HR compared with resting state (delta HR) or by exponential modeling, with measurement intervals ranging from 0-4 s up to 2 min. Delta HR was used to evaluate HRonsetshort over the first 4 s of exercise, as well as for analyzing HRonsetlong. In exponential modeling, the HR response to dynamic exercise is biphasic, consisting of fast (parasympathetic, 0-10 s) and slow (sympathetic, 1-4 min) components. Although available studies differed largely in measurement protocols, cross-sectional and longitudinal training studies showed that studies analyzing HRonset

  7. Review of multi-dimensional large-scale kinetic simulation and physics validation of ion acceleration in relativistic laser-matter interaction

    SciTech Connect

    Wu, Hui-Chun; Hegelich, B.M.; Fernandez, J.C.; Shah, R.C.; Palaniyappan, S.; Jung, D.; Yin, L; Albright, B.J.; Bowers, K.; Huang, C.; Kwan, T.J.

    2012-06-19

    Two new experimental technologies enabled realization of Break-out afterburner (BOA) - High quality Trident laser and free-standing C nm-targets. VPIC is an powerful tool for fundamental research of relativistic laser-matter interaction. Predictions from VPIC are validated - Novel BOA and Solitary ion acceleration mechanisms. VPIC is a fully explicit Particle In Cell (PIC) code: models plasma as billions of macro-particles moving on a computational mesh. VPIC particle advance (which typically dominates computation) has been optimized extensively for many different supercomputers. Laser-driven ions lead to realization promising applications - Ion-based fast ignition; active interrogation, hadron therapy.

  8. [Correlations of anthropometric and psychodynamic indexes of accelerant boys and girls (georgians) and their comparing with the data of women and men of normal physical development].

    PubMed

    Nadashvili, L A

    2005-12-01

    Our goal was to determine relations of anthropometric and psychodynamic indexes of accelerant women and men (Georgian) and compare them with the data of women and men of normal physical development. For this reason we have investigated 100 accelerants -- 45 girls and 55 boys. On the basis of our study we have shown that correlations between subspecies of temperament and anthropometrical signs in accelerant women and men are equal or lower among men. From the point of view of character form -- these data in women are comparatively high, and correlation of intellect and types of mood and anthropometric signs are equal. In comparison with the men of normal development, in accelerant men are noticed law interconnection between anthropometrical and psychodynamic data except subspecies of intellect, which is equal in every case. Connection between the types of mood and anthropometric data are moderate (in the limits 0.3-0.4). Men accelerants (Georgians) are brachymorphic somatotypes; they are distinguished by phlegmatic temperament, introversion, middle logic intellect, conflict -- statistic mood; according to the mood they are harmonic-dynamic constitutional types.

  9. Computational studies and optimization of wakefield accelerators

    SciTech Connect

    Tsung, Frank S.; Bruhwiler, David L.; Cary, John R.; Esarey, Eric H.; Mori, Warren B.; Vay, Jean-Luc; Martins, Samuel F.; Katsouleas, Tom; Cormier-Michel, Estelle; Fawley, William M.; Huang, Chengkun; Wang, Xiadong; Cowan, Ben; Decyk, Victor K.; Fonseca, Ricardo A.; Lu, Wei; Messmer, Peter; Mullowney, Paul; Nakamura, Kei; Paul, Kevin; Plateau, Guillaume R.; Schroeder, Carl B.; Silva, Luis O.; Toth, Csaba; Geddes, C.G.R.; Tzoufras, Michael; Antonsen, Tom; Vieira, Jorge; Leemans, Wim P.

    2008-06-16

    Laser- and particle beam-driven plasma wakefield accelerators produce accelerating fields thousands of times higher than radio-frequency accelerators, offering compactness and ultrafast bunches to extend the frontiers of high energy physics and to enable laboratory-scale radiation sources. Large-scale kinetic simulations provide essential understanding of accelerator physics to advance beam performance and stability and show and predict the physics behind recent demonstration of narrow energy spread bunches. Benchmarking between codes is establishing validity of the models used and, by testing new reduced models, is extending the reach of simulations to cover upcoming meter-scale multi-GeV experiments. This includes new models that exploit Lorentz boosted simulation frames to speed calculations. Simulations of experiments showed that recently demonstrated plasma gradient injection of electrons can be used as an injector to increase beam quality by orders of magnitude. Simulations are now also modeling accelerator stages of tens of GeV, staging of modules, and new positron sources to design next-generation experiments and to use in applications in high energy physics and light sources.

  10. Efficacy of physical activity interventions in post-natal populations: systematic review, meta-analysis and content coding of behaviour change techniques.

    PubMed

    Gilinsky, Alyssa Sara; Dale, Hannah; Robinson, Clare; Hughes, Adrienne R; McInnes, Rhona; Lavallee, David

    2015-01-01

    This systematic review and meta-analysis reports the efficacy of post-natal physical activity change interventions with content coding of behaviour change techniques (BCTs). Electronic databases (MEDLINE, CINAHL and PsychINFO) were searched for interventions published from January 1980 to July 2013. Inclusion criteria were: (i) interventions including ≥1 BCT designed to change physical activity behaviour, (ii) studies reporting ≥1 physical activity outcome, (iii) interventions commencing later than four weeks after childbirth and (iv) studies including participants who had given birth within the last year. Controlled trials were included in the meta-analysis. Interventions were coded using the 40-item Coventry, Aberdeen & London - Refined (CALO-RE) taxonomy of BCTs and study quality assessment was conducted using Cochrane criteria. Twenty studies were included in the review (meta-analysis: n = 14). Seven were interventions conducted with healthy inactive post-natal women. Nine were post-natal weight management studies. Two studies included women with post-natal depression. Two studies focused on improving general well-being. Studies in healthy populations but not for weight management successfully changed physical activity. Interventions increased frequency but not volume of physical activity or walking behaviour. Efficacious interventions always included the BCTs 'goal setting (behaviour)' and 'prompt self-monitoring of behaviour'.

  11. Simulating ion beam extraction from a single aperture triode acceleration column: A comparison of the beam transport codes IGUN and PBGUNS with test stand data

    SciTech Connect

    Patel, A.; Wills, J. S. C.; Diamond, W. T.

    2008-04-15

    Ion beam extraction from two different ion sources with single aperture triode extraction columns was simulated with the particle beam transport codes PBGUNS and IGUN. For each ion source, the simulation results are compared to experimental data generated on well-equipped test stands. Both codes reproduced the qualitative behavior of the extracted ion beams to incremental and scaled changes to the extraction electrode geometry observed on the test stands. Numerical values of optimum beam currents and beam emittance generated by the simulations also agree well with test stand data.

  12. BOOK REVIEW Cracking the Einstein Code: Relativity and the Birth of Black Hole Physics With an Afterword by Roy Kerr Cracking the Einstein Code: Relativity and the Birth of Black Hole Physics With an Afterword by Roy Kerr

    NASA Astrophysics Data System (ADS)

    Carr, Bernard

    2011-02-01

    General relativity is arguably the most beautiful scientific theory ever conceived but its status within mainstream physics has vacillated since it was proposed in 1915. It began auspiciously with the successful explanation of the precession of Mercury and the dramatic confirmation of light-bending in the 1919 solar eclipse expedition, which turned Einstein into an overnight celebrity. Though little noticed at the time, there was also Karl Schwarzschild's discovery of the spherically symmetric solution in 1916 (later used to predict the existence of black holes) and Alexander Friedmann's discovery of the cosmological solution in 1922 (later confirmed by the discovery of the cosmic expansion). Then for 40 years the theory was more or less forgotten, partly because most physicists were turning their attention to the even more radical developments of quantum theory but also because the equations were too complicated to solve except in situations involving special symmetries or very weak gravitational fields (where general relativity is very similar to Newtonian theory). Furthermore, it was not clear that strong gravitational fields would ever arise in the real universe and, even if they did, it seemed unlikely that Einstein's equations could then be solved. So research in relativity became a quiet backwater as mainstream physics swept forward in other directions. Even Einstein lost interest, turning his attention to the search for a unified field theory. This book tells the remarkable story of how the tide changed in 1963, when the 28-year-old New Zealand mathematician Roy Kerr discovered an exact solution of Einstein's equations which represents a rotating black hole, thereby cracking the code of the title. The paper was just a few pages long, it being left for others to fill in the extensive beautiful mathematics which underlay the result, but it ushered in a golden age of relativity and is now one of the most cited works in physics. Coincidentally, Kerr

  13. Accelerate Implementation of the WHO Global Code of Practice on International Recruitment of Health Personnel: Experiences From the South East Asia Region

    PubMed Central

    Tangcharoensathien, Viroj; Travis, Phyllida

    2016-01-01

    Strengthening the health workforce and universal health coverage (UHC) are among key targets in the heath-related Sustainable Development Goals (SDGs) to be committed by the United Nations (UN) Member States in September 2015. The health workforce, the backbone of health systems, contributes to functioning delivery systems. Equitable distribution of functioning services is indispensable to achieve one of the UHC goals of equitable access. This commentary argues the World Health Organization (WHO) Global Code of Practice on International Recruitment of Health Personnel is relevant to the countries in the South East Asia Region (SEAR) as there is a significant outflow of health workers from several countries and a significant inflow in a few, increased demand for health workforce in high- and middle-income countries, and slow progress in addressing the "push factors." Awareness and implementation of the Code in the first report in 2012 was low but significantly improved in the second report in 2015. An inter-country workshop in 2015 convened by WHO SEAR to review progress in implementation of the Code was an opportunity for countries to share lessons on policy implementation, on retention of health workers, scaling up health professional education and managing in and out migration. The meeting noted that capturing outmigration of health personnel, which is notoriously difficult for source countries, is possible where there is an active recruitment management through government to government (G to G) contracts or licensing the recruiters and mandatory reporting requirement by them. According to the 2015 second report on the Code, the size and profile of outflow health workers from SEAR source countries is being captured and now also increasingly being shared by destination country professional councils. This is critical information to foster policy action and implementation of the Code in the Region. PMID:26673648

  14. MARS code developments, benchmarking and applications

    SciTech Connect

    Mokhov, N.V.

    2000-03-24

    Recent developments of the MARS Monte Carlo code system for simulation of hadronic and electromagnetic cascades in shielding, accelerator and detector components in the energy range from a fraction of an electron volt up to 100 TeV are described. The physical model of hadron and lepton interactions with nuclei and atoms has undergone substantial improvements. These include a new nuclear cross section library, a model for soft prior production, a cascade-exciton model, a dual parton model, deuteron-nucleus and neutrino-nucleus interaction models, a detailed description of negative hadron and muon absorption, and a unified treatment of muon and charged hadron electro-magnetic interactions with matter. New algorithms have been implemented into the code and benchmarked against experimental data. A new Graphical-User Interface has been developed. The code capabilities to simulate cascades and generate a variety of results in complex systems have been enhanced. The MARS system includes links to the MCNP code for neutron and photon transport below 20 MeV, to the ANSYS code for thermal and stress analyses and to the STRUCT code for multi-turn particle tracking in large synchrotrons and collider rings. Results of recent benchmarking of the MARS code are presented. Examples of non-trivial code applications are given for the Fermilab Booster and Main Injector, for a 1.5 MW target station and a muon storage ring.

  15. Cross-sectional association of the number of neighborhood facilities assessed using postal code with objectively measured physical activity: the Saku cohort study.

    PubMed

    Yasunaga, Akitomo; Murakami, Haruka; Morita, Akemi; Deura, Kijyo; Aiba, Naomi; Watanabe, Shaw; Miyachi, Motohiko

    2016-01-01

    Objectives The aim of this study was to examine the association between the number of neighborhood facilities that were assessed according to postal code and objectively measured physical activity by using an accelerometer in community-dwelling Japanese people.Methods The participants included 1,274 Japanese people aged 30-84 years from the Saku cohort study. As neighborhood facilities related to physical activity, we extracted information regarding train stations, supermarkets/convenience stores, postal offices/banks, hospitals/clinics, public offices/community centers, cultural facilities/public children's houses, parks, and sports facilities by using each participant's postal code from the online version of the iTownPages directory published by Nippon Telegraph and Telephone Corporation (NTT) and the official homepage of the Saku City Government Office. We measured each participant's physical activity level using an accelerometer, and calculated the average daily step count and the average weekly period of moderate-to-vigorous intensity (≥3 metabolic equivalents of tasks [METs]) physical activity. The association between two selected physical activity-related variables and the numbers of eight types of neighborhood facilities were analyzed by multivariate logistic regression analysis for people aged 30-64 years and for those aged over 65 years.Results On multivariate logistic regression analysis, meeting the 23 METs h/week of moderate-to-vigorous intensity physical activity was significantly and positively associated with the number of supermarkets/convenience stores in the neighborhood in both age groups. In addition, meeting the desired daily step count outlined in the Japanese National Health Promotion guidelines was positively related to the number of postal offices/banks for people aged over 65 years.Conclusion The results of this study suggest that a sufficient number of neighborhood facilities (i.e., stores, banks, and postal offices) is closely

  16. Smartphones as Experimental Tools: Different Methods to Determine the Gravitational Acceleration in Classroom Physics by Using Everyday Devices

    ERIC Educational Resources Information Center

    Kuhn, Jochen; Vogt, Patrik

    2013-01-01

    New media technology becomes more and more important for our daily life as well as for teaching physics. Within the scope of our N.E.T. research project we develop experiments using New Media Experimental Tools (N.E.T.) in physics education and study their influence on students learning abilities. We want to present the possibilities e.g. of…

  17. Plasma-based accelerator structures

    SciTech Connect

    Schroeder, Carl B.

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  18. Accelerator Technology Division

    NASA Astrophysics Data System (ADS)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  19. BAR-CODE BASED WEIGHT MEASUREMENT STATION FOR PHYSICAL INVENTORY TAKING OF PLUTONIUM OXIDE CONTAINERS AT THE MINING AND CHEMICAL COMBINE RADIOCHEMICAL REPROCESSING PLANT NEAR KRASNOYARSK, SIBERIA.

    SciTech Connect

    SUDA,S.

    1999-09-20

    This paper describes the technical tasks being implemented to computerize the physical inventory taking (PIT) at the Mining and Chemical Combine (Gorno-Khimichesky Kombinat, GKhK) radiochemical plant under the US/Russian cooperative nuclear material protection, control, and accounting (MPC and A) program. Under the MPC and A program, Lab-to-Lab task agreements with GKhK were negotiated that involved computerized equipment for item verification and confirmatory measurement of the Pu containers. Tasks under Phase I cover the work for demonstrating the plan and procedures for carrying out the comparison of the Pu container identification on the container with the computerized inventory records. In addition to the records validation, the verification procedures include the application of bar codes and bar coded TIDs to the Pu containers. Phase II involves the verification of the Pu content. A plan and procedures are being written for carrying out confirmatory measurements on the Pu containers.

  20. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  1. Numerical simulation of an accelerator injector

    SciTech Connect

    Boyd, J.K.; Caporaso, G.J.; Cole, A.G.

    1985-05-09

    Accelerator injector designs have been evaluated using two computer codes. The first code self consistently follows relativistic particles in two dimensions. Fields are obtained in the Darwin model which includes inductive effects. This code is used to study cathode emission and acceleration to full injector voltage. The second code transports a fixed segment of a beam along the remainder of the beam line. Using these two codes the effects of electrode configuration on emittance, beam quality and beam transport have been studied.

  2. The syndrome coding technique and its application to fast event selection in high-energy physics experiments

    SciTech Connect

    Nikityuk, N.M.

    1993-01-01

    The problems in the use of the theory and practice of algebraic coding theory for data compression and processing in multichannel charged-particle detectors are discussed. A system of analogies between the theories of correcting codes and hodoscopic systems is described. The main result of this approach is the development of radically new logic units, such as parallel encoders for t > 1 signals, majority coincidence circuits for a large number of inputs, dynamically programmable modules, and special-purpose processors with algebraic structure based on elements of the Galois field GF(2{sup m}) for fast event selection. It is also shown how calculations in Galois fields can be used to design dynamically programcontrolled logic modules, which appear promising for use in trigger systems.

  3. Preliminary assessment of existing experimental data for validation ofreactor physics codes and data for NGNP design and analysis.

    SciTech Connect

    Terry, W. K.; Jewell, J. K.; Briggs, J. B.; Taiwo, T. A.; Park, W.S.; Khalil, H. S.

    2005-10-25

    The Next Generation Nuclear Plant (NGNP), a demonstration reactor and hydrogen production facility proposed for construction at the INEEL, is expected to be a high-temperature gas-cooled reactor (HTGR). Computer codes used in design and safety analysis for the NGNP must be benchmarked against experimental data. The INEEL and ANL have examined information about several past and present experimental and prototypical facilities based on HTGR concepts to assess the potential of these facilities for use in this benchmarking effort. Both reactors and critical facilities applicable to pebble-bed and prismatic block-type cores have been considered. Four facilities--HTR-PROTEUS, HTR-10, ASTRA, and AVR--appear to have the greatest potential for use in benchmarking codes for pebble-bed reactors. Similarly, for the prismatic block-type reactor design, two experiments have been ranked as having the highest priority--HTTR and VHTRC.

  4. Optimization and Parallelization of the Thermal-Hydraulic Sub-channel Code CTF for High-Fidelity Multi-physics Applications

    SciTech Connect

    Salko, Robert K; Schmidt, Rodney; Avramova, Maria N

    2014-01-01

    This paper describes major improvements to the computational infrastructure of the CTF sub-channel code so that full-core sub-channel-resolved simulations can now be performed in much shorter run-times, either in stand-alone mode or as part of coupled-code multi-physics calculations. These improvements support the goals of the Department Of Energy (DOE) Consortium for Advanced Simulations of Light Water (CASL) Energy Innovation Hub to develop high fidelity multi-physics simulation tools for nuclear energy design and analysis. A set of serial code optimizations--including fixing computational inefficiencies, optimizing the numerical approach, and making smarter data storage choices--are first described and shown to reduce both execution time and memory usage by about a factor of ten. Next, a Single Program Multiple Data (SPMD) parallelization strategy targeting distributed memory Multiple Instruction Multiple Data (MIMD) platforms and utilizing domain-decomposition is presented. In this approach, data communication between processors is accomplished by inserting standard MPI calls at strategic points in the code. The domain decomposition approach implemented assigns one MPI process to each fuel assembly, with each domain being represented by its own CTF input file. The creation of CTF input files, both for serial and parallel runs, is also fully automated through use of a pre-processor utility that takes a greatly reduced set of user input over the traditional CTF input file. To run CTF in parallel, two additional libraries are currently needed; MPI, for inter-processor message passing, and the Parallel Extensible Toolkit for Scientific Computation (PETSc), which is leveraged to solve the global pressure matrix in parallel. Results presented include a set of testing and verification calculations and performance tests assessing parallel scaling characteristics up to a full core, sub-channel-resolved model of Watts Bar Unit 1 under hot full-power conditions (193 17x17

  5. Shoulder physical activity, functional disability and task difficulties in patients with stiff shoulders: interpretation from RT3 accelerator.

    PubMed

    Yang, Jing-Lan; Lin, Jiu-Jenq; Huang, Han-Yi; Huang, Tsun-Shun; Chao, Yu Wen

    2014-08-01

    We determined whether the degree of symptom-related functional disability was related to daily physical activity of the shoulder in subjects with stiff shoulders (SSs). Responsiveness and a clinically meaningful level of discrimination between improvement and non-improvement for shoulder physical activity (SPA) were determined. Twenty-six subjects with SSs participated. Shoulder physical activity was assessed by RT3 accelerometers fixed on the humerus during daily 14-h data collection periods twice a week for 2 weeks. A moderate correlation coefficient was found between SPA and functional disability (β = .47). Based on our cohort design and sample, we suggest that SPA (higher than 101.8 counts, hard-moderate or hard tasks) during daily activity are associated with (with at least 83% probability) non-improvement in an individual with SS. Compared to the non-improvement group, the improvement group had less duration of sedentary activity, less frequency and duration of hard tasks, and more frequency and duration of easy tasks (p < 0.01). Appropriate guidance on shoulder physical activities for subjects with SS is important to consider in rehabilitation strategies for these subjects. In our sample, a hard level of shoulder physical activity and sedentary activity should be cautious for these subjects. Further study is needed to validate therapeutic effect of physical activity on the course of patient improvement in subjects with SSs.

  6. Impact accelerations

    NASA Technical Reports Server (NTRS)

    Vongierke, H. E.; Brinkley, J. W.

    1975-01-01

    The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

  7. Comparing the standards of one metabolic equivalent of task in accurately estimating physical activity energy expenditure based on acceleration.

    PubMed

    Kim, Dohyun; Lee, Jongshill; Park, Hoon Ki; Jang, Dong Pyo; Song, Soohwa; Cho, Baek Hwan; Jung, Yoo-Suk; Park, Rae-Woong; Joo, Nam-Seok; Kim, In Young

    2016-08-24

    The purpose of the study is to analyse how the standard of resting metabolic rate (RMR) affects estimation of the metabolic equivalent of task (MET) using an accelerometer. In order to investigate the effect on estimation according to intensity of activity, comparisons were conducted between the 3.5 ml O2 · kg(-1) · min(-1) and individually measured resting VO2 as the standard of 1 MET. MET was estimated by linear regression equations that were derived through five-fold cross-validation using 2 types of MET values and accelerations; the accuracy of estimation was analysed through cross-validation, Bland and Altman plot, and one-way ANOVA test. There were no significant differences in the RMS error after cross-validation. However, the individual RMR-based estimations had as many as 0.5 METs of mean difference in modified Bland and Altman plots than RMR of 3.5 ml O2 · kg(-1) · min(-1). Finally, the results of an ANOVA test indicated that the individual RMR-based estimations had less significant differences between the reference and estimated values at each intensity of activity. In conclusion, the RMR standard is a factor that affects accurate estimation of METs by acceleration; therefore, RMR requires individual specification when it is used for estimation of METs using an accelerometer.

  8. Towards a heavy-ion transport capability in the MARS15 Code

    SciTech Connect

    Mokhov, N. V.; Gudima, K. K.; Mashnik, S. G.; Rakhno, I. L.; Striganov, S.

    2004-04-01

    In order to meet the challenges of new accelerator and space projects and further improve modelling of radiation effects in microscopic objects, heavy-ion interaction and transport physics have been recently incorporated into the MARS15 Monte Carlo code. A brief description of new modules is given in comparison with experimental data. The MARS Monte Carlo code is widely used in numerous accelerator, detector, shielding and cosmic ray applications. The needs of the Relativistic Heavy-Ion Collider, Large Hadron Collider, Rare Isotope Accelerator and NASA projects have recently induced adding heavy-ion interaction and transport physics to the MARS15 code. The key modules of the new implementation are described below along with their comparisons to experimental data.

  9. Laser acceleration

    NASA Astrophysics Data System (ADS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  10. AN INTEGRAL REACTOR PHYSICS EXPERIMENT TO INFER ACTINIDE CAPTURE CROSS-SECTIONS FROM THORIUM TO CALIFORNIUM WITH ACCELERATOR MASS SPECTROMETRY

    SciTech Connect

    G. Youinou; M. Salvatores; M. Paul; R. Pardo; G. Palmiotti; F. Kondev; G. Imel

    2010-04-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectroscopy (AMS) technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am and 248Cm.

  11. Summary of 1990 Code Conference

    SciTech Connect

    Cooper, R.K.; Chan, Kwok-Chi D.

    1990-01-01

    The Conference on Codes and the Linear Accelerator Community was held in Los Alamos in January 1990, and had approximately 100 participants. This conference was the second in a series which has as its goal the exchange of information about codes and code practices among those writing and actually using these codes for the design and analysis of linear accelerators and their components. The first conference was held in San Diego in January 1988, and concentrated on beam dynamics codes and Maxwell solvers. This most recent conference concentrated on 3-D codes and techniques to handle the large amounts of data required for three-dimensional problems. In addition to descriptions of codes, their algorithms and implementations, there were a number of paper describing the use of many of the codes. Proceedings of both these conferences are available. 3 refs., 2 tabs.

  12. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  13. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph; /Fermilab

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  14. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph

    2010-07-29

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?.

  15. Polar Codes

    DTIC Science & Technology

    2014-12-01

    density parity check (LDPC) code, a Reed–Solomon code, and three convolutional codes. iii CONTENTS EXECUTIVE SUMMARY...the most common. Many civilian systems use low density parity check (LDPC) FEC codes, and the Navy is planning to use LDPC for some future systems...other forward error correction methods: a turbo code, a low density parity check (LDPC) code, a Reed–Solomon code, and three convolutional codes

  16. Suppression of the aging-associated decline in physical performance by a combination of resveratrol intake and habitual exercise in senescence-accelerated mice.

    PubMed

    Murase, Takatoshi; Haramizu, Satoshi; Ota, Noriyasu; Hase, Tadashi

    2009-08-01

    The decline in physical performance with increasing age is a crucial problem in our aging society. We examined the effects of resveratrol, a natural polyphenolic compound present in grapes, in combination with habitual exercise on the aging-associated decline in physical performance in senescence-accelerated prone mice (SAMP1). The endurance capacity of SAMP1 mice undergoing an exercise regimen (SAMP1-Ex) decreased over 12 weeks whereas that of SAMP1 mice fed 0.2% (w/w) resveratrol along with exercise (SAMP1-ExRes) remained significantly higher. In the SAMP1-ExRes group, there was a significant increase in oxygen consumption and skeletal muscle mRNA levels of mitochondrial function-related enzymes. These results suggest that the intake of resveratrol, together with habitual exercise, is beneficial for suppressing the aging-related decline in physical performance and that these effects are attributable, at least in part, to improved mitochondrial function in skeletal muscle.

  17. The SCEC Petascale Cyberfacility for Physics-based Seismic Hazard Analysis (PetaSHA): Accelerating SCEC Research Using High Performance Computing

    NASA Astrophysics Data System (ADS)

    Maechling, P. J.; Jordan, T. H.; Kesselman, C.; Moore, R.; Minster, J. B.; SCEC Collaboration

    2007-12-01

    The SCEC Community Modeling Environment (SCEC/CME) collaboration is extending SCEC's program of seismic hazard research using high performance computing with the NSF-funded Petascale Cyberfacility for Physics-based Seismic Hazard Analysis (PetaSHA) Project. The SCEC PetaSHA project is a collaboration of geoscientists and computer scientists that integrate geophysical numerical modeling codes with leading-edge cyberinfrastructure to perform seismic hazard research at large-scales and high-resolution using national academic supercomputing facilities. The PetaSHA computational capabilities are organized around the development of robust, re-usable, well-validated simulation systems we call computational platforms. Researchers on the PetaSHA Project are currently developing the DynaShake Platform (dynamic rupture simulations), the TeraShake Platform (wave propagation simulations), the CyberShake Platform (physics-based probabilistic seismic hazard analysis), the BroadBand Platform (deterministic and stochastic modeling of high frequency synthetic waveforms), the Full 3D Tomography (F3DT) Platform (improvements in structural representations), as well as using and extending the OpenSHA Platform (Probabilistic Seismic Hazard Analysis). We will describe several current PetaSHA research projects including the application of the DynaShake Platform to dynamic rupture modeling of the ShakeOut source, the use of the TeraShake Platform, including the URS- Graves, SDSU-Olsen and CMU-Hercules Anelastic Wave Propagation codes, to model 1Hz ShakeOut simulations, the use of the CyberShake Platform to investigate physics-based PSHA hazard curves, and the use of the F3DT Platform to produce an improved structural model for a large region in southern California.

  18. CEBAF Accelerator Achievements

    NASA Astrophysics Data System (ADS)

    Chao, Y. C.; Drury, M.; Hovater, C.; Hutton, A.; Krafft, G. A.; Poelker, M.; Reece, C.; Tiefenback, M.

    2011-05-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  19. Towards a heavy-ion transport capability in the MARS15 code

    SciTech Connect

    Nikolai V. Mokhov et al.

    2004-05-12

    In order to meet the challenges of new accelerator and space projects and further improve modeling of radiation effects in microscopic objects, heavy-ion interaction and transport physics have been recently incorporated into the MARS15 Monte Carlo code. A brief description of new modules is given in comparison with experimental data.

  20. Influence of familiarization on the reliability of vertical jump and acceleration sprinting performance in physically active men.

    PubMed

    Moir, Gavin; Button, Chris; Glaister, Mark; Stone, Michael H

    2004-05-01

    The purpose of the present study was to determine the number of familiarization sessions required to obtain an accurate measure of reliability associated with loaded vertical jump and 20-m sprint running performance. Ten physically active men attended 5 separate testing sessions over a 3-week period where they performed unloaded and loaded (10-kg extra load) countermovement (CMJ) and static (SJ) jumps, followed by straight-line 20-m sprints. Jump height was recorded for the vertical jumps using a jump mat, while the time for 10 m and 20 m was recorded during the sprints using photocells. The highest (jump conditions) and fastest (sprint) of 3 trials performed during each of the 5 testing sessions was used in the subsequent analysis. Familiarization was assessed using the scores obtained during the 5 separate testing sessions. Reliability was assessed by calculating intraclass correlation coefficients (ICCs) and coefficient of variation (CV). No significant differences were obtained between the testing sessions for any of the measures. ICCs ranged from 0.89 to 0.95, while CVs ranged from 1.9 to 2.6%. These results indicate that high levels of reliability can be achieved without the need for familiarization sessions when using loaded and unloaded CMJ and SJ and 20-m sprint performance with physically active men.

  1. High Gradient Accelerator Research

    SciTech Connect

    Temkin, Richard

    2016-07-12

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  2. Clinical coding. Code breakers.

    PubMed

    Mathieson, Steve

    2005-02-24

    --The advent of payment by results has seen the role of the clinical coder pushed to the fore in England. --Examinations for a clinical coding qualification began in 1999. In 2004, approximately 200 people took the qualification. --Trusts are attracting people to the role by offering training from scratch or through modern apprenticeships.

  3. Comparison of children's free-living physical activity derived from wrist and hip raw accelerations during the segmented week.

    PubMed

    Noonan, Robert J; Boddy, Lynne M; Kim, Youngwon; Knowles, Zoe R; Fairclough, Stuart J

    2016-11-14

    This study assessed children's physical activity (PA) levels derived from wrist-worn GENEActiv and hip-worn ActiGraph GT3X+ accelerometers and examined the comparability of PA levels between the two devices throughout the segmented week. One hundred and twenty-nine 9-10-year-old children (79 girls) wore a GENEActiv (GAwrist) and ActiGraph GT3X+ (AGhip) accelerometer on the left wrist and right hip, respectively, for 7 days. Mean minutes of light PA (LPA) and moderate-to-vigorous PA (MVPA) per weekday (whole-day, before-school, school and after-school) and weekend day (whole-day, morning and afternoon-evening) segments were calculated, and expressed as percentage of segment time. Repeated measures analysis of variance examined differences in LPA and MVPA between GAwrist and AGhip for each time segment. Bland-Altman plots assessed between-device agreement for LPA and MVPA for whole weekday and whole weekend day segments. Correlations between GAwrist and AGhip were weak for LPA (r = 0.18-0.28), but strong for MVPA (r = 0.80-0.86). LPA and MVPA levels during all weekday and weekend day segments were significantly higher for GAwrist than AGhip (p < 0.001). The largest inter-device percent difference of 26% was observed in LPA during the school day segment. Our data suggest that correction factors are needed to improve raw PA level comparability between GAwrist and AGhip.

  4. TH-C-BRB-00: Open Source Hardware in Medical Physics and Its Potential to Accelerate Innovation.

    PubMed

    Therriault-Proulx, Francois

    2016-06-01

    By definition, Open Source Hardware (OSH) is "hardware whose design is made publicly available so that anyone can study, modify, distribute, make, and sell the design or hardware based on that design". The advantages of OSH are multiple and the movement has been growing exponentially over the last couple years, leading to the spread and evolution of 3D printing technologies, the creation of affordable and easy to use micro-controller boards (Arduino, Raspberry Pi, etc.), as well as a plurality of other "hands-on"/DIY projects. As we have seen over the past few years with 3D printing, where the number of projects benefiting clinical practice as grown significantly, the highly educated and technology savvy Medical Physics community is positioned to take advantage of and benefit from paradigm-shifting movements. Sharing of knowledge, know-how, and technology can be a key factor in furthering the impact medical physicists can have. Whether it is to develop phantoms, applicators, detector holders or devices based on the use of motors and sensors, sharing design files significantly enables further development. Because these designs would be massively peer-reviewed through their online publication, improvements would be made, and the creators of the design would be rewarded with an increase number of citation of their work. A curated database of software and hardware projects can be an invaluable to the field, but a critical mass of contributors is likely needed to guarantee the most impact. This symposium will discuss the benefits and hurdles for such an endeavor.

  5. Physical exercise accelerates reentrainment of human sleep-wake cycle but not of plasma melatonin rhythm to 8-h phase-advanced sleep schedule.

    PubMed

    Yamanaka, Yujiro; Hashimoto, Satoko; Tanahashi, Yusuke; Nishide, Shin-Ya; Honma, Sato; Honma, Ken-Ichi

    2010-03-01

    Effects of timed physical exercise were examined on the reentrainment of sleep-wake cycle and circadian rhythms to an 8-h phase-advanced sleep schedule. Seventeen male adults spent 12 days in a temporal isolation facility with dim light conditions (<10 lux). The sleep schedule was phase-advanced by 8 h from their habitual sleep times for 4 days, which was followed by a free-run session for 6 days, during which the subjects were deprived of time cues. During the shift schedule, the exercise group (n = 9) performed physical exercise with a bicycle ergometer in the early and middle waking period for 2 h each. The control group (n = 8) sat on a chair at those times. Their sleep-wake cycles were monitored every day by polysomnography and/or weight sensor equipped with a bed. The circadian rhythm in plasma melatonin was measured on the baseline day before phase shift: on the 4th day of shift schedule and the 5th day of free-run. As a result, the sleep-onset on the first day of free-run in the exercise group was significantly phase-advanced from that in the control and from the baseline. On the other hand, the circadian melatonin rhythm was significantly phase-delayed in the both groups, showing internal desynchronization of the circadian rhythms. The sleep-wake cycle resynchronized to the melatonin rhythm by either phase-advance or phase-delay shifts in the free-run session. These findings indicate that the reentrainment of the sleep-wake cycle to a phase-advanced schedule occurs independent of the circadian pacemaker and is accelerated by timed physical exercise.

  6. A code for calculating intrabeam scattering and beam lifetime

    SciTech Connect

    Kim, C.H.

    1997-05-01

    Beam emittances in a circular accelerator with a high beam intensity are strongly affected by the small angle intrabeam Coulomb scattering. In the computer simulation model the authors present here they used three coupled nonlinear differential equations to describe the evolution of the emittances in the transverse and the longitudinal planes. These equations include terms which take into account the intra-beam scattering, adiabatic damping, microwave instabilities, synchrotron damping, and quantum excitations. A code is generated to solve the equations numerically and incorporated into a FORTRAN code library. Circular high intensity physics routines are included in the library such as intrabeam scattering, Touschek scattering, and the bunch lengthening effect of higher harmonic cavities. The code runs presently in the PC environment. Description of the code and some examples are presented.

  7. Physics.

    ERIC Educational Resources Information Center

    Bromley, D. Allan

    1980-01-01

    The author presents the argument that the past few years, in terms of new discoveries, insights, and questions raised, have been among the most productive in the history of physics. Selected for discussion are some of the most important new developments in physics research. (Author/SA)

  8. FERMILAB ACCELERATOR R&D PROGRAM TOWARDS INTENSITY FRONTIER ACCELERATORS : STATUS AND PROGRESS

    SciTech Connect

    Shiltsev, Vladimir

    2016-11-15

    The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centrepiece of the US domestic HEP program at Fermilab. Operation, upgrade and development of the accelerators for the near- term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators and present its status and progress. INTENSITY FRONTIER ACCELERATORS

  9. Physical Exercise and Antidepressants Enhance BDNF Targeting in Hippocampal CA3 Dendrites: Further Evidence of a Spatial Code for BDNF Splice Variants

    PubMed Central

    Baj, Gabriele; D'Alessandro, Valentina; Musazzi, Laura; Mallei, Alessandra; Sartori, Cesar R; Sciancalepore, Marina; Tardito, Daniela; Langone, Francesco; Popoli, Maurizio; Tongiorgi, Enrico

    2012-01-01

    Brain-derived neurotrophic factor (BDNF) is encoded by multiple BDNF transcripts, whose function is unclear. We recently showed that a subset of BDNF transcripts can traffic into distal dendrites in response to electrical activity, while others are segregated into the somatoproximal domains. Physical exercise and antidepressant treatments exert their beneficial effects through upregulation of BDNF, which is required to support survival and differentiation of newborn dentate gyrus (DG) neurons. While these DG processes are required for the antidepressant effect, a role for CA1 in antidepressant action has been excluded, and the effect on CA3 neurons remains unclear. Here, we show for the first time that physical exercise and antidepressants induce local increase of BDNF in CA3. Voluntary physical exercise for 28 consecutive days, or 2-week treatment with 10 mg/kg per day fluoxetine or reboxetine, produced a global increase of BDNF mRNA and protein in the neuronal somata of the whole hippocampus and a specific increase of BDNF in dendrites of CA3 neurons. This increase was accounted for by BDNF exon 6 variant. In cultured hippocampal neurons, application of serotonin or norepinephrine (10–50 μM) induced increase in synaptic transmission and targeting of BDNF mRNA in dendrites. The increased expression of BDNF in CA3 dendrites following antidepressants or exercise further supports the neurotrophin hypothesis of antidepressants action and confirms that the differential subcellular localization of BDNF mRNA splice variants provides a spatial code for a selective expression of BDNF in specific subcellular districts. This selective expression may be exploited to design more specific antidepressants. PMID:22318196

  10. Physical exercise and antidepressants enhance BDNF targeting in hippocampal CA3 dendrites: further evidence of a spatial code for BDNF splice variants.

    PubMed

    Baj, Gabriele; D'Alessandro, Valentina; Musazzi, Laura; Mallei, Alessandra; Sartori, Cesar R; Sciancalepore, Marina; Tardito, Daniela; Langone, Francesco; Popoli, Maurizio; Tongiorgi, Enrico

    2012-06-01

    Brain-derived neurotrophic factor (BDNF) is encoded by multiple BDNF transcripts, whose function is unclear. We recently showed that a subset of BDNF transcripts can traffic into distal dendrites in response to electrical activity, while others are segregated into the somatoproximal domains. Physical exercise and antidepressant treatments exert their beneficial effects through upregulation of BDNF, which is required to support survival and differentiation of newborn dentate gyrus (DG) neurons. While these DG processes are required for the antidepressant effect, a role for CA1 in antidepressant action has been excluded, and the effect on CA3 neurons remains unclear. Here, we show for the first time that physical exercise and antidepressants induce local increase of BDNF in CA3. Voluntary physical exercise for 28 consecutive days, or 2-week treatment with 10 mg/kg per day fluoxetine or reboxetine, produced a global increase of BDNF mRNA and protein in the neuronal somata of the whole hippocampus and a specific increase of BDNF in dendrites of CA3 neurons. This increase was accounted for by BDNF exon 6 variant. In cultured hippocampal neurons, application of serotonin or norepinephrine (10-50 μM) induced increase in synaptic transmission and targeting of BDNF mRNA in dendrites. The increased expression of BDNF in CA3 dendrites following antidepressants or exercise further supports the neurotrophin hypothesis of antidepressants action and confirms that the differential subcellular localization of BDNF mRNA splice variants provides a spatial code for a selective expression of BDNF in specific subcellular districts. This selective expression may be exploited to design more specific antidepressants.

  11. Load management strategy for Particle-In-Cell simulations in high energy particle acceleration

    NASA Astrophysics Data System (ADS)

    Beck, A.; Frederiksen, J. T.; Dérouillat, J.

    2016-09-01

    In the wake of the intense effort made for the experimental CILEX project, numerical simulation campaigns have been carried out in order to finalize the design of the facility and to identify optimal laser and plasma parameters. These simulations bring, of course, important insight into the fundamental physics at play. As a by-product, they also characterize the quality of our theoretical and numerical models. In this paper, we compare the results given by different codes and point out algorithmic limitations both in terms of physical accuracy and computational performances. These limitations are illustrated in the context of electron laser wakefield acceleration (LWFA). The main limitation we identify in state-of-the-art Particle-In-Cell (PIC) codes is computational load imbalance. We propose an innovative algorithm to deal with this specific issue as well as milestones towards a modern, accurate high-performance PIC code for high energy particle acceleration.

  12. Efficient modeling of laser-plasma accelerator staging experiments using INF&RNO

    NASA Astrophysics Data System (ADS)

    Benedetti, C.; Schroeder, C. B.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2017-03-01

    The computational framework INF&RNO (INtegrated Fluid & paRticle simulatioN cOde) allows for fast and accurate modeling, in 2D cylindrical geometry, of several aspects of laser-plasma accelerator physics. In this paper, we present some of the new features of the code, including the quasistatic Particle-In-Cell (PIC)/fluid modality, and describe using different computational grids and time steps for the laser envelope and the plasma wake. These and other features allow for a speedup of several orders of magnitude compared to standard full 3D PIC simulations while still retaining physical fidelity. INF&RNO is used to support the experimental activity at the BELLA Center, and we will present an example of the application of the code to the laser-plasma accelerator staging experiment.

  13. FAA Smoke Transport Code

    SciTech Connect

    Domino, Stefan; Luketa-Hanlin, Anay; Gallegos, Carlos

    2006-10-27

    FAA Smoke Transport Code, a physics-based Computational Fluid Dynamics tool, which couples heat, mass, and momentum transfer, has been developed to provide information on smoke transport in cargo compartments with various geometries and flight conditions. The software package contains a graphical user interface for specification of geometry and boundary conditions, analysis module for solving the governing equations, and a post-processing tool. The current code was produced by making substantial improvements and additions to a code obtained from a university. The original code was able to compute steady, uniform, isothermal turbulent pressurization. In addition, a preprocessor and postprocessor were added to arrive at the current software package.

  14. SLINGSHOT - a Coilgun Design Code

    SciTech Connect

    MARDER, BARRY M.

    2001-09-01

    The Sandia coilgun [1,2,3,4,5] is an inductive electromagnetic launcher. It consists of a sequence of powered, multi-turn coils surrounding a flyway of circular cross-section through which a conducting armature passes. When the armature is properly positioned with respect to a coil, a charged capacitor is switched into the coil circuit. The rising coil currents induce a current in the armature, producing a repulsive accelerating force. The basic numerical tool for modeling the coilgun is the SLINGSHOT code, an expanded, user-friendly successor to WARP-10 [6]. SLINGSHOT computes the currents in the coils and armature, finds the forces produced by those currents, and moves the armature through the array of coils. In this approach, the cylindrically symmetric coils and armature are subdivided into concentric hoops with rectangular cross-section, in each of which the current is assumed to be uniform. The ensemble of hoops are treated as coupled circuits. The specific heats and resistivities of the hoops are found as functions of temperature and used to determine the resistive heating. The code calculates the resistances and inductances for all hoops, and the mutual inductances for all hoop pairs. Using these, it computes the hoop currents from their circuit equations, finds the forces from the products of these currents and the mutual inductance gradient, and moves the armature. Treating the problem as a set of coupled circuits is a fast and accurate approach compared to solving the field equations. Its use, however, is restricted to problems in which the symmetry dictates the current paths. This paper is divided into three parts. The first presents a demonstration of the code. The second describes the input and output. The third part describes the physical models and numerical methods used in the code. It is assumed that the reader is familiar with coilguns.

  15. Iterative acceleration methods for Monte Carlo and deterministic criticality calculations

    SciTech Connect

    Urbatsch, T.J.

    1995-11-01

    If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.

  16. GPU-optimized Code for Long-term Simulations of Beam-beam Effects in Colliders

    SciTech Connect

    Roblin, Yves; Morozov, Vasiliy; Terzic, Balsa; Aturban, Mohamed A.; Ranjan, D.; Zubair, Mohammed

    2013-06-01

    We report on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, a previously computationally prohibitive long-term simulations become tractable. We use the new code to model the proposed medium-energy electron-ion collider (MEIC) at Jefferson Lab.

  17. Large electrostatic accelerators

    SciTech Connect

    Jones, C.M.

    1984-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of large electrostatic accelerators designed to operate at terminal potentials of 20 MV or above. In this paper, the author briefly discusses the status of these new accelerators and also discusses several recent technological advances which may be expected to further improve their performance. The paper is divided into four parts: (1) a discussion of the motivation for the construction of large electrostatic accelerators, (2) a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, (3) a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and (4) a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year. Due to time and space constraints, discussion is restricted to consideration of only tandem accelerators.

  18. Parallel beam dynamics simulation of linear accelerators

    SciTech Connect

    Qiang, Ji; Ryne, Robert D.

    2002-01-31

    In this paper we describe parallel particle-in-cell methods for the large scale simulation of beam dynamics in linear accelerators. These techniques have been implemented in the IMPACT (Integrated Map and Particle Accelerator Tracking) code. IMPACT is being used to study the behavior of intense charged particle beams and as a tool for the design of next-generation linear accelerators. As examples, we present applications of the code to the study of emittance exchange in high intensity beams and to the study of beam transport in a proposed accelerator for the development of accelerator-driven waste transmutation technologies.

  19. Beam Breakup Effects in Dielectric Based Accelerators

    SciTech Connect

    Schoessow, P.; Kanareykin, A.; Jing, C.; Kustov, A.; Altmark, A.; Power, J. G.; Gai, W.

    2009-01-22

    The dynamics of the beam in structure-based wakefield accelerators leads to beam stability issues not ordinarily found in other machines. In particular, the high current drive beam in an efficient wakefield accelerator loses a large fraction of its energy in the decelerator structure, resulting in physical emittance growth, increased energy spread, and the possibility of head-tail instability for an off axis beam, all of which can lead to severe reduction of beam intensity. Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators as well. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements at the AWA facility in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable. The numerical part of this research is based on a particle-Green's function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.

  20. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  1. Investigation on iterative multiuser detection physical layer network coding in two-way relay free-space optical links with turbulences and pointing errors.

    PubMed

    Abu-Almaalie, Zina; Ghassemlooy, Zabih; Bhatnagar, Manav R; Le-Minh, Hoa; Aslam, Nauman; Liaw, Shien-Kuei; Lee, It Ee

    2016-11-20

    Physical layer network coding (PNC) improves the throughput in wireless networks by enabling two nodes to exchange information using a minimum number of time slots. The PNC technique is proposed for two-way relay channel free space optical (TWR-FSO) communications with the aim of maximizing the utilization of network resources. The multipair TWR-FSO is considered in this paper, where a single antenna on each pair seeks to communicate via a common receiver aperture at the relay. Therefore, chip interleaving is adopted as a technique to separate the different transmitted signals at the relay node to perform PNC mapping. Accordingly, this scheme relies on the iterative multiuser technique for detection of users at the receiver. The bit error rate (BER) performance of the proposed system is examined under the combined influences of atmospheric loss, turbulence-induced channel fading, and pointing errors (PEs). By adopting the joint PNC mapping with interleaving and multiuser detection techniques, the BER results show that the proposed scheme can achieve a significant performance improvement against the degrading effects of turbulences and PEs. It is also demonstrated that a larger number of simultaneous users can be supported with this new scheme in establishing a communication link between multiple pairs of nodes in two time slots, thereby improving the channel capacity.

  2. Accelerator Technology Division annual report, FY 1989

    SciTech Connect

    Not Available

    1990-06-01

    This paper discusses: accelerator physics and special projects; experiments and injectors; magnetic optics and beam diagnostics; accelerator design and engineering; radio-frequency technology; accelerator theory and simulation; free-electron laser technology; accelerator controls and automation; and high power microwave sources and effects.

  3. Progress in Modeling Electron Cloud Effects in HIF Accelerators

    NASA Astrophysics Data System (ADS)

    Cohen, R. H.; Friedman, A.; Molvik, A. W.; Azevedo, A.; Vay, J.-L.; Furman, M. A.; Stoltz, P. H.

    2003-10-01

    Stray electrons can arise in positive-charge accelerators for heavy ion fusion (or other applications) from ionization of gas (ambient or released from walls), or via secondary emission. Their accumulation is affected by the beam potential and duration, and the accelerating and confining fields. We present electron orbit simulations which show the resultant e-cloud distribution; ion simulations with prescribed e-clouds which show the effect on ion beam quality; a gyro-averaged model for including electron dynamics in ion simulations, and its implementation status; and progress in merging the capabilities of WARP (3-D PIC code for HIF) (D.P. Grote, A. Friedman, I. Haber, Proc. 1996 Comp. Accel. Physics Conf., AIP Proc. 391), 51 (1996), with those of POSINST (e-clouds in high-energy accelerators) (M.A. Furman, LBNL-41482/CBP Note 247/LHC Project Report 180, May 20, 1998).

  4. Neural network-based sensor signal accelerator.

    SciTech Connect

    Vogt, M. C.

    2000-10-16

    A strategy has been developed to computationally accelerate the response time of a generic electronic sensor. The strategy can be deployed as an algorithm in a control system or as a physical interface (on an embedded microcontroller) between a slower responding external sensor and a higher-speed control system. Optional code implementations are available to adjust algorithm performance when computational capability is limited. In one option, the actual sensor signal can be sampled at the slower rate with adaptive linear neural networks predicting the sensor's future output and interpolating intermediate synthetic output values. In another option, a synchronized collection of predictors sequentially controls the corresponding synthetic output voltage. Error is adaptively corrected in both options. The core strategy has been demonstrated with automotive oxygen sensor data. A prototype interface device is under construction. The response speed increase afforded by this strategy could greatly offset the cost of developing a replacement sensor with a faster physical response time.

  5. Overview of WARP, a particle code for Heavy Ion Fusion

    SciTech Connect

    Friedman, A.; Grote, D.P.; Callahan, D.A.; Langdon, A.B.; Haber, I.

    1993-02-22

    The beams in a Heavy Ion beam driven inertial Fusion (HIF) accelerator must be focused onto small spots at the fusion target, and so preservation of beam quality is crucial. The nonlinear self-fields of these space-charge-dominated beams can lead to emittance growth; thus a self-consistent field description is necessary. We have developed a multi-dimensional discrete-particle simulation code, WARP, and are using it to study the behavior of HIF beams. The code`s 3d package combines features of an accelerator code and a particle-in-cell plasma simulation, and can efficiently track beams through many lattice elements and around bends. We have used the code to understand the physics of aggressive drift-compression in the MBE-4 experiment at Lawrence Berkeley Laboratory (LBL). We have applied it to LBL`s planned ILSE experiments, to various ``recirculator`` configurations, and to the study of equilibria and equilibration processes. Applications of the 3d package to ESQ injectors, and of the r, z package to longitudinal stability in driver beams, are discussed in related papers.

  6. Accelerator simulation using computers

    SciTech Connect

    Lee, M.; Zambre, Y.; Corbett, W.

    1992-01-01

    Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a multi-track'' simulation and analysis code can be used for these applications.

  7. Accelerator simulation using computers

    SciTech Connect

    Lee, M.; Zambre, Y.; Corbett, W.

    1992-01-01

    Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a ``multi-track`` simulation and analysis code can be used for these applications.

  8. Ethical coding.

    PubMed

    Resnik, Barry I

    2009-01-01

    It is ethical, legal, and proper for a dermatologist to maximize income through proper coding of patient encounters and procedures. The overzealous physician can misinterpret reimbursement requirements or receive bad advice from other physicians and cross the line from aggressive coding to coding fraud. Several of the more common problem areas are discussed.

  9. TRACK : the new beam dynamics code.

    SciTech Connect

    Aseev, V. N.; Ostroumov, P. N.; Lessner, E. S.; Mustapha, B.; Physics

    2005-01-01

    The new ray-tracing code TRACK originally developed to fulfill the special requirements of the RIA accelerator systems is a general beam dynamics code. It is currently being used for the design and simulation of future proton and heavy-ion linacs at several Labs. This paper presents a general description of the code TRACK emphasizing its main new features and recent updates.

  10. Wake field acceleration experiments

    SciTech Connect

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics. I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs.

  11. Impact of SciDAC on accelerator projects across the office of science through electromagnetic modeling

    NASA Astrophysics Data System (ADS)

    Ko, K.; Folwell, N.; Ge, L.; Guetz, A.; Ivanov, V.; Kabel, A.; Kowalski, M.; Lee, L.; Li, Z.; Ng, C.; Prudencio, E.; Schussman, G.; Uplenchwar, R.; Xiao, L.; Collaborators, ISICs/SAPP

    2005-01-01

    Electromagnetic Modelling led by SLAC is a principal component of the "Advanced Computing for 21st Century Accelerator Science and Technology" SciDAC project funded through the Office of High Energy Physics. This large team effort comprises three other national laboratories (LBNL, LLNL, SNL) and six universities (CMU, Columbia, RPI, Stanford, UC Davis and U of Wisconsin) with the goal to develop a set of parallel electromagnetic codes based on unstructured grids to target challenging problems in accelerators, and solve them to unprecedented realism and accuracy. Essential to the code development are the collaborations with the ISICs/SAPP in eigensolvers, meshing, adaptive refinement, shape optimization and visualization (see "Achievements in ISICs/SAPP Collaborations for Electromagnetic Modelling of Accelerators"). Supported by these advances in computational science, we have successfully performed the large-scale simulations that have impacted important accelerator projects across the Office of Science (SC) including the Positron Electron Project (PEP) -II, Next Linear Collider (NLC) and the International Linear Collider (ILC) in High Energy Physics (HEP), the Rare Isotope Accelerator (RIA) in Nuclear Physics (NP) and the Linac Coherent Light Source (LCLS) in Basic Energy Science (BES).

  12. Symposium report on frontier applications of accelerators

    SciTech Connect

    Parsa, Z.

    1993-09-28

    This report contains viewgraph material on the following topics: Electron-Positron Linear Colliders; Unconventional Colliders; Prospects for UVFEL; Accelerator Based Intense Spallation; Neutron Sources; and B Physics at Hadron Accelerators with RHIC as an Example.

  13. Energetics, Physics and Impact of Large-Scale Jets: Fast and Super-Eddington or Slow and Multi-TeV Accelerators?

    NASA Astrophysics Data System (ADS)

    Georganopoulos, Markos

    We propose to answer a long-standing, important question on the nature of quasar largescale jets: are they fast (Lorentz factors 10-20) and powerful (in many cases superEddington) or slow, sub-Eddington, and multi-TeV particle accelerators?. The answer has direct bearing on the physics of cluster gas heating by powerful jets, an important feedback mechanism in the structure formation process. Also, for slow jets the beamingcorrected radiated power of the large scale jet may be comparable to, or even exceed that of the blazar (core) with important implications for the GeV background radiation and the heating of intergalactic gas by TeV photons, something that has been suggested as the reason for the dearth of dwarf galaxies compared with the cold dark matter predictions. The question of the jet nature has been open since the 2000s, when Chandra detected anomalously high levels of X-rays from dozens of powerful kpc-scale radio/optical jets, indicating a separate origin from the radio-optical synchrotron emission. The widely accepted model for these X-rays has been a very powerful highly-relativistic kpc-scale jet producing inverse Compton emission by up-scattering the cosmic microwave background (IC/CMB), though the X-rays could also be synchrotron emission from a multi-TeV electron population accelerated in situ, as both models can reproduce the observed radio to X-ray spectra. However, very recent work by our group has ruled out the IC/CMB model in two cases. In the case of 3C 273, the uniquely determined GeV flux predicted by the IC/CMB model overproduces the 99.9% flux limit obtained from Fermi gamma-ray observations. These results do not, however, rule out IC/CMB in general, although they do bring synchrotron, slow, multi-TeV accelerator jets to the forefront. In conjunction with radio-to-X-ray multi-wavelength archival imaging, we will extend our study to a much larger sample of over 70 quasar-hosted jets, using the Fermi method we pioneered, while also

  14. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    ScienceCinema

    Andrei Seryi

    2016-07-12

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  15. Current trends in non-accelerator particle physics: 1, Neutrino mass and oscillation. 2, High energy neutrino astrophysics. 3, Detection of dark matter. 4, Search for strange quark matter. 5, Magnetic monopole searches

    SciTech Connect

    He, Yudong |

    1995-07-01

    This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled `Neutrino Mass and Oscillation`, `High Energy Neutrino Astrophysics`, `Detection of Dark Matter`, `Search for Strange Quark Matter`, and `Magnetic Monopole Searches`. The report is introduced by a survey of the field and a brief description of each of the author`s papers.

  16. The Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.

    1992-01-01

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies.

  17. The Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.

    1992-09-01

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies.

  18. Sharing code.

    PubMed

    Kubilius, Jonas

    2014-01-01

    Sharing code is becoming increasingly important in the wake of Open Science. In this review I describe and compare two popular code-sharing utilities, GitHub and Open Science Framework (OSF). GitHub is a mature, industry-standard tool but lacks focus towards researchers. In comparison, OSF offers a one-stop solution for researchers but a lot of functionality is still under development. I conclude by listing alternative lesser-known tools for code and materials sharing.

  19. Accelerated testing of space batteries

    NASA Technical Reports Server (NTRS)

    Mccallum, J.; Thomas, R. E.; Waite, J. H.

    1973-01-01

    An accelerated life test program for space batteries is presented that fully satisfies empirical, statistical, and physical criteria for validity. The program includes thermal and other nonmechanical stress analyses as well as mechanical stress, strain, and rate of strain measurements.

  20. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  1. Introductory Physics Experiments Using the Wiimote

    NASA Astrophysics Data System (ADS)

    Somers, William; Rooney, Frank; Ochoa, Romulo

    2009-03-01

    The Wii, a video game console, is a very popular device with millions of units sold worldwide over the past two years. Although computationally it is not a powerful machine, to a physics educator its most important components can be its controllers. The Wiimote (or remote) controller contains three accelerometers, an infrared detector, and Bluetooth connectivity at a relatively low price. Thanks to available open source code, any PC with Bluetooth capability can detect the information sent out by the Wiimote. We have designed several experiments for introductory physics courses that make use of the accelerometers and Bluetooth connectivity. We have adapted the Wiimote to measure the: variable acceleration in simple harmonic motion, centripetal and tangential accelerations in circular motion, and the accelerations generated when students lift weights. We present the results of our experiments and compare them with those obtained when using motion and/or force sensors.

  2. Developing a framework for predicting upper extremity muscle activities, postures, velocities, and accelerations during computer use: the effect of keyboard use, mouse use, and individual factors on physical exposures.

    PubMed

    Bruno Garza, Jennifer L; Catalano, Paul J; Katz, Jeffrey N; Huysmans, Maaike A; Dennerlein, Jack T

    2012-01-01

    Prediction models were developed based on keyboard and mouse use in combination with individual factors that could be used to predict median upper extremity muscle activities, postures, velocities, and accelerations experienced during computer use. In the laboratory, 25 participants performed five simulated computer trials with different amounts of keyboard and mouse use ranging from a highly keyboard-intensive trial to a highly mouse-intensive trial. During each trial, muscle activity and postures of the shoulder and wrist and velocities and accelerations of the wrists, along with percentage keyboard and mouse use, were measured. Four individual factors (hand length, shoulder width, age, and gender) were also measured on the day of data collection. Percentage keyboard and mouse use explained a large amount of the variability in wrist velocities and accelerations. Although hand length, shoulder width, and age were each significant predictors of at least one median muscle activity, posture, velocity, or acceleration exposure, these individual factors explained very little variability in addition to percentage keyboard and mouse use in any of the physical exposures investigated. The amounts of variability explained for models predicting median wrist velocities and accelerations ranged from 75 to 84% but were much lower for median muscle activities and postures (0-50%). RMS errors ranged between 8 to 13% of the range observed. While the predictions for wrist velocities and accelerations may be able to be used to improve exposure assessment for future epidemiologic studies, more research is needed to identify other factors that may improve the predictions for muscle activities and postures.

  3. Dielectric laser accelerators

    NASA Astrophysics Data System (ADS)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  4. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  5. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  6. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  7. Accelerators for America's Future

    NASA Astrophysics Data System (ADS)

    Bai, Mei

    2016-03-01

    Particle accelerator, a powerful tool to energize beams of charged particles to a desired speed and energy, has been the working horse for investigating the fundamental structure of matter and fundermental laws of nature. Most known examples are the 2-mile long Stanford Linear Accelerator at SLAC, the high energy proton and anti-proton collider Tevatron at FermiLab, and Large Hadron Collider that is currently under operation at CERN. During the less than a century development of accelerator science and technology that led to a dazzling list of discoveries, particle accelerators have also found various applications beyond particle and nuclear physics research, and become an indispensible part of the economy. Today, one can find a particle accelerator at almost every corner of our lives, ranging from the x-ray machine at the airport security to radiation diagnostic and therapy in hospitals. This presentation will give a brief introduction of the applications of this powerful tool in fundermental research as well as in industry. Challenges in accelerator science and technology will also be briefly presented

  8. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  9. High intensity hadron accelerators

    SciTech Connect

    Teng, L.C.

    1989-05-01

    This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

  10. High field gradient particle accelerator

    DOEpatents

    Nation, John A.; Greenwald, Shlomo

    1989-01-01

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  11. High field gradient particle accelerator

    DOEpatents

    Nation, J.A.; Greenwald, S.

    1989-05-30

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  12. Numerical Verification of the Power Transfer and Wakefield Coupling in the Clic Two-Beam Accelerator

    SciTech Connect

    Candel, Arno; Li, Z.; Ng, C.; Rawat, V.; Schussman, G.; Ko, K.; Syratchev, I.; Grudiev, A.; Wuensch, W.; /CERN

    2011-08-19

    The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its two-beam accelerator (TBA) concept envisions complex 3D structures, which must be modeled to high accuracy so that simulation results can be directly used to prepare CAD drawings for machining. The required simulations include not only the fundamental mode properties of the accelerating structures but also the Power Extraction and Transfer Structure (PETS), as well as the coupling between the two systems. Time-domain simulations will be performed to understand pulse formation, wakefield damping, fundamental power transfer and wakefield coupling in these structures. Applying SLAC's parallel finite element code suite, these large-scale problems will be solved on some of the largest supercomputers available. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel two-beam accelerator scheme.

  13. Shielding analyses for repetitive high energy pulsed power accelerators

    NASA Astrophysics Data System (ADS)

    Jow, H. N.; Rao, D. V.

    Sandia National Laboratories (SNL) designs, tests and operates a variety of accelerators that generate large amounts of high energy Bremsstrahlung radiation over an extended time. Typically, groups of similar accelerators are housed in a large building that is inaccessible to the general public. To facilitate independent operation of each accelerator, test cells are constructed around each accelerator to shield it from the radiation workers occupying surrounding test cells and work-areas. These test cells, about 9 ft. high, are constructed of high density concrete block walls that provide direct radiation shielding. Above the target areas (radiation sources), lead or steel plates are used to minimize skyshine radiation. Space, accessibility and cost considerations impose certain restrictions on the design of these test cells. SNL Health Physics division is tasked to evaluate the adequacy of each test cell design and compare resultant dose rates with the design criteria stated in DOE Order 5480.11. In response, SNL Health Physics has undertaken an intensive effort to assess existing radiation shielding codes and compare their predictions against measured dose rates. This paper provides a summary of the effort and its results.

  14. The Accelerator Markup Language and the Universal Accelerator Parser

    SciTech Connect

    Sagan, David; Forster, M.; Bates, D.; Wolski, A.; Schmidt, F.; Walker, N.J.; Larrieu, Theodore; Roblin, Yves; Pelaia, T.; Tenenbaum, P.; Woodley, M.; Reiche, S.

    2006-07-01

    A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.

  15. The Accelerator Markup Language and the Universal Accelerator Parser

    SciTech Connect

    Sagan, D.; Forster, M.; Bates, D.A.; Wolski, A.; Schmidt, F.; Walker, N.J.; Larrieu, T.; Roblin, Y.; Pelaia, T.; Tenenbaum, P.; Woodley, M.; Reiche, S.; /UCLA

    2006-10-06

    A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally, this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.

  16. Acceleration schedules for a recirculating heavy-ion accelerator

    SciTech Connect

    Sharp, W.M.; Grote, D.P.

    2002-05-01

    Recent advances in solid-state switches have made it feasible to design programmable, high-repetition-rate pulsers for induction accelerators. These switches could lower the cost of recirculating induction accelerators, such as the ''small recirculator'' at Lawrence Livermore National Laboratory (LLNL), by substantially reducing the number of induction modules. Numerical work is reported here to determine what effects the use of fewer pulsers at higher voltage would have on the beam quality of the LLNL small recirculator. Lattices with different numbers of pulsers are examined using the fluid/envelope code CIRCE, and several schedules for acceleration and compression are compared for each configuration. For selected schedules, the phase-space dynamics is also studied using the particle-in-cell code WARP3d.

  17. Sharing code

    PubMed Central

    Kubilius, Jonas

    2014-01-01

    Sharing code is becoming increasingly important in the wake of Open Science. In this review I describe and compare two popular code-sharing utilities, GitHub and Open Science Framework (OSF). GitHub is a mature, industry-standard tool but lacks focus towards researchers. In comparison, OSF offers a one-stop solution for researchers but a lot of functionality is still under development. I conclude by listing alternative lesser-known tools for code and materials sharing. PMID:25165519

  18. Magnetically accelerated foils for shock wave experiments

    NASA Astrophysics Data System (ADS)

    Neff, S.; Ford, J.; Wright, S.; Martinez, D.; Plechaty, C.; Presura, R.

    2009-08-01

    Many astrophysical phenomena involve the interaction of a shock wave with an inhomogeneous background medium. Using scaled experiments with inhomogeneous foam targets makes it possible to study relevant physics in the laboratory to better understand the mechanisms of shock compression and to benchmark astrophysical simulation codes. First experiments on Zebra at the Nevada Terawatt Facility (NTF) have demonstrated flyer acceleration to sufficiently high velocities (up to 5 km/s) and that laser shadowgraphy can image sound fronts in transparent targets. Based on this, we designed an optimized setup to improve the flyer parameters (higher speed and mass) to create shock waves in transparent media. Once x-ray backlighting with the Leopard laser at NTF is operational, we will switch to foam targets with parameters relevant for laboratory astrophysics.

  19. Hardware Accelerated Simulated Radiography

    SciTech Connect

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-04-12

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32 bit floating point texture capabilities to obtain validated solutions to the radiative transport equation for X-rays. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedra that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester. We show that the hardware accelerated solution is faster than the current technique used by scientists.

  20. Figuring the Acceleration of the Simple Pendulum

    ERIC Educational Resources Information Center

    Lieberherr, Martin

    2011-01-01

    The centripetal acceleration has been known since Huygens' (1659) and Newton's (1684) time. The physics to calculate the acceleration of a simple pendulum has been around for more than 300 years, and a fairly complete treatise has been given by C. Schwarz in this journal. But sentences like "the acceleration is always directed towards the…

  1. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  2. Pulsed Plasma Accelerator Modeling

    NASA Technical Reports Server (NTRS)

    Goodman, M.; Kazeminezhad, F.; Owens, T.

    2009-01-01

    This report presents the main results of the modeling task of the PPA project. The objective of this task is to make major progress towards developing a new computational tool with new capabilities for simulating cylindrically symmetric 2.5 dimensional (2.5 D) PPA's. This tool may be used for designing, optimizing, and understanding the operation of PPA s and other pulsed power devices. The foundation for this task is the 2-D, cylindrically symmetric, magnetohydrodynamic (MHD) code PCAPPS (Princeton Code for Advanced Plasma Propulsion Simulation). PCAPPS was originally developed by Sankaran (2001, 2005) to model Lithium Lorentz Force Accelerators (LLFA's), which are electrode based devices, and are typically operated in continuous magnetic field to the model, and implementing a first principles, self-consistent algorithm to couple the plasma and power circuit that drives the plasma dynamics.

  3. Requirements of a proton beam accelerator for an accelerator-driven reactor

    SciTech Connect

    Takahashi, H.; Zhao, Y.; Tsoupas, N.; An, Y.; Yamazaki, Y.

    1997-12-31

    When the authors first proposed an accelerator-driven reactor, the concept was opposed by physicists who had earlier used the accelerator for their physics experiments. This opposition arose because they had nuisance experiences in that the accelerator was not reliable, and very often disrupted their work as the accelerator shut down due to electric tripping. This paper discusses the requirements for the proton beam accelerator. It addresses how to solve the tripping problem and how to shape the proton beam.

  4. Elementary particle physics

    NASA Technical Reports Server (NTRS)

    Perkins, D. H.

    1986-01-01

    Elementary particle physics is discussed. Status of the Standard Model of electroweak and strong interactions; phenomena beyond the Standard Model; new accelerator projects; and possible contributions from non-accelerator experiments are examined.

  5. Numerical modelling of physical processes and structural changes in metals under intensive irradiation with use of CRS code: dislocations, twinning, evaporation and stress waves

    NASA Astrophysics Data System (ADS)

    Mayer, A. E.; Borodin, E. N.; Krasnikov, V. S.; Mayer, P. N.

    2014-11-01

    CRS computer program is presented, which calculates the dynamical deformation of metals under irradiation by high-current electron and powerful ion beams. The incorporated mathematical models allow one to calculate stresses, deformations and structural changes induced by the irradiation. The CRS code numerically solves the equations system, which consists of continua mechanics equations, supplemented by equations of dynamics and kinetics of structural defects: dislocations, grain boundaries, twins, micro-cracks and vapour bubbles. The dislocation plasticity model, the grain boundary sliding model, the mechanical twinning model, the spall fracture model and the non-equilibrium evaporation model are incorporated in the code. The energy release function for electron beam can be calculated within the code, while it can be exported from over programs for ion beam. The CRS code can be a useful tool in theoretical estimation and interpretation of experiments in the field of materials modification by intensive energy fluxes. Restricted rate of plastic deformation provides high values of shear stresses and action of several competitive plasticity mechanisms. Non-equilibrium evaporation of metal in the energy release zone leads to a metastable state of overheated melt, which results in formation of tensile wave following the stress wave in the solid part of the irradiated metal.

  6. W.K.H. Panofsky Prize in Experimental Particle Physics: The design, construction and performance of the B Factory accelerator facilities, PEP-II and KEKB

    NASA Astrophysics Data System (ADS)

    Dorfan, Jonathan

    2016-03-01

    The discovery and elucidation of CP violation in the B-meson system presented daunting challenges for the accelerator and detector facilities. This talk discusses how these challenges were met and overcome in the electron-positron colliding-beam accelerator facilities PEP-II (at SLAC) and KEKB (at KEK). The key challenge was to produce unprecedentedly large numbers of B-mesons in a geometry that provided high-statistics, low-background samples of decays to CP eigenstates. This was realized with asymmetric collisions at the Γ(4S) at peak luminosities in excess of 3 ×1033 /sq. cm/sec. Specialized optics were developed to generate efficient, low background, multi-bunch collisions in an energy-asymmetric collision geometry. Novel technologies for the RF, vacuum and feedback systems permitted the storage of multi-amp, multi-bunch beams of electrons and positrons, thereby generating high peak luminosities. Accelerator uptimes greater than 95 percent, combined with high-intensity injection systems, ensured large integrated luminosity. Both facilities rapidly attained their design specifications and ultimately far exceeded the projected performance expectations for both peak and integrated luminosity.

  7. MCNPX{trademark} -- The LAHET{trademark}/MCNP{trademark} code merger

    SciTech Connect

    Hughes, H.G.; Adams, K.J.; Chadwick, M.B.

    1997-08-01

    The MCNP code is written and maintained by Group X-TM at Los Alamos National Laboratory. In response to the demands of the accelerator community, the authors have undertaken a major effort to expand the capabilities of MCNP to increase the set of transportable particles; to make use of newly evaluated high-energy nuclear data tables for neutrons, protons, and potentially other particles; and to incorporate physics models for use where tabular data are unavailable. A preliminary version of the expanded code, called MCNPX, has now been issued for testing. The new code includes all existing LAHET physics modules, and has the ability to utilize the 150-MeV data libraries that have recently been released by LANL Group T-2.

  8. Accelerators for Intensity Frontier Research

    SciTech Connect

    Derwent, Paul; /Fermilab

    2012-05-11

    In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.

  9. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  10. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  11. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  12. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  13. Polar Code Validation

    DTIC Science & Technology

    1989-09-30

    Unclassified 2a SECURITY CLASSiF-ICATiON AUTHORIT’Y 3 DIStRIBUTION AVAILABILITY OF REPORT N,A Approved for public release; 2o DECLASSIFICAIiON DOWNGRADING SCH DI...SUMMARY OF POLAR ACHIEVEMENTS ..... .......... 3 3 . POLAR CODE PHYSICAL MODELS ..... ............. 5 3.1 PL-ASMA Su ^"ru5 I1LS SH A...11 Structure of the Bipolar Plasma Sheath Generated by SPEAR I ... ...... 1 3 The POLAR Code Wake Model: Comparison with in Situ Observations . . 23

  14. Speech coding

    SciTech Connect

    Ravishankar, C., Hughes Network Systems, Germantown, MD

    1998-05-08

    Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the

  15. Physics Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Describes equipment, activities, and experiments useful in physics instruction, including among others, a list of articles relating to physics topics, computer interface that makes a computer cost effective, use of a guitar in vibrating string experiments, and photoelectric aids to the measurement of distance, speed, velocity, and acceleration.…

  16. Centripetal Acceleration: Often Forgotten or Misinterpreted

    ERIC Educational Resources Information Center

    Singh, Chandralekha

    2009-01-01

    Acceleration is a fundamental concept in physics which is taught in mechanics at all levels. Here, we discuss some challenges in teaching this concept effectively when the path along which the object is moving has a curvature and centripetal acceleration is present. We discuss examples illustrating that both physics teachers and students have…

  17. Measurement of Coriolis Acceleration with a Smartphone

    ERIC Educational Resources Information Center

    Shaku, Asif; Kraft, Jakob

    2016-01-01

    Undergraduate physics laboratories seldom have experiments that measure the Coriolis acceleration. This has traditionally been the case owing to the inherent complexities of making such measurements. Articles on the experimental determination of the Coriolis acceleration are few and far between in the physics literature. However, because modern…

  18. Transient simulation of ram accelerator flowfields

    NASA Astrophysics Data System (ADS)

    Drabczuk, Randall P.; Rolader, G.; Dash, S.; Sinha, N.; York, B.

    1993-01-01

    This paper describes the development of an advanced computational fluid dynamic (CFD) simulation capability in support of the USAF Armament Directorate ram accelerator research initiative. The state-of-the-art CRAFT computer code has been specialized for high fidelity, transient ram accelerator simulations via inclusion of generalized dynamic gridding, solution adaptive grid clustering, and high pressure thermo-chemistry. Selected ram accelerator simulations are presented that serve to exhibit the CRAFT code capabilities and identify some of the principle research/design Issues.

  19. Transient simulation of ram accelerator flowfields

    NASA Astrophysics Data System (ADS)

    Sinha, N.; York, B. J.; Dash, S. M.; Drabczuk, R.; Rolader, G. E.

    1992-10-01

    This paper describes the development of an advanced computational fluid dynamic (CFD) simulation capability in support of the U.S. Air Force Armament Directorate's ram accelerator research initiative. The state-of-the-art CRAFT computer code has been specialized for high fidelity, transient ram accelerator simulations via inclusion of generalized dynamic gridding, solution adaptive grid clustering, high pressure thermochemistry, etc. Selected ram accelerator simulations are presented which serve to exhibit the CRAFT code's capabilities and identify some of the principal research/design issues.

  20. The FLUKA code for space applications: recent developments

    NASA Technical Reports Server (NTRS)

    Andersen, V.; Ballarini, F.; Battistoni, G.; Campanella, M.; Carboni, M.; Cerutti, F.; Empl, A.; Fasso, A.; Ferrari, A.; Gadioli, E.; Garzelli, M. V.; Lee, K.; Ottolenghi, A.; Pelliccioni, M.; Pinsky, L. S.; Ranft, J.; Roesler, S.; Sala, P. R.; Wilson, T. L.; Townsend, L. W. (Principal Investigator)

    2004-01-01

    The FLUKA Monte Carlo transport code is widely used for fundamental research, radioprotection and dosimetry, hybrid nuclear energy system and cosmic ray calculations. The validity of its physical models has been benchmarked against a variety of experimental data over a wide range of energies, ranging from accelerator data to cosmic ray showers in the earth atmosphere. The code is presently undergoing several developments in order to better fit the needs of space applications. The generation of particle spectra according to up-to-date cosmic ray data as well as the effect of the solar and geomagnetic modulation have been implemented and already successfully applied to a variety of problems. The implementation of suitable models for heavy ion nuclear interactions has reached an operational stage. At medium/high energy FLUKA is using the DPMJET model. The major task of incorporating heavy ion interactions from a few GeV/n down to the threshold for inelastic collisions is also progressing and promising results have been obtained using a modified version of the RQMD-2.4 code. This interim solution is now fully operational, while waiting for the development of new models based on the FLUKA hadron-nucleus interaction code, a newly developed QMD code, and the implementation of the Boltzmann master equation theory for low energy ion interactions. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  1. Investigation of (123)I production using electron accelerator.

    PubMed

    Avetisyan, Albert; Avagyan, Robert; Dallakyan, Ruben; Avdalyan, Gohar; Dobrovolsky, Nikolay; Gavalyan, Vasak; Kerobyan, Ivetta; Harutyunyan, Gevorg

    2017-04-01

    The possibility of (123)I isotope production with the help of the high-intensity bremsstrahlung photons produced by the electron beam of the LUE50 linear electron accelerator at the A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute [YerPhI]) is considered. The production method has been established and shown to be successful. The (124)Xe(γ,n)(123)Xe→(123)I nuclear reaction has been investigated and the cross-section was calculated by nuclear codes TALYS 1.6 and EMPIRE 3.2. The optimum parameter of the thickness of the target was determined by GEANT4 code. For the normalized yield of (123)I, the value of 143Bq/(mg·μA·h) has been achieved.

  2. Hypoxia in the St. Lawrence Estuary: How a Coding Error Led to the Belief that “Physics Controls Spatial Patterns”

    PubMed Central

    2015-01-01

    Two fundamental sign errors were found in a computer code used for studying the oxygen minimum zone (OMZ) and hypoxia in the Estuary and Gulf of St. Lawrence. These errors invalidate the conclusions drawn from the model, and call into question a proposed mechanism for generating OMZ that challenges classical understanding. The study in question is being cited frequently, leading the discipline in the wrong direction. PMID:26397371

  3. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: The structural analysis of protein sequences based on the quasi-amino acids code

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Tang, Xu-Qing; Xu, Zhen-Yuan

    2009-01-01

    Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Genome Project, it comes the postgenome era when the proteomics technology is emerging. This paper studies protein molecule from the algebraic point of view. The algebraic system (Σ, +, *) is introduced, where Σ is the set of 64 codons. According to the characteristics of (Σ, +, *), a novel quasi-amino acids code classification method is introduced and the corresponding algebraic operation table over the set ZU of the 16 kinds of quasi-amino acids is established. The internal relation is revealed about quasi-amino acids. The results show that there exist some very close correlations between the properties of the quasi-amino acids and the codon. All these correlation relationships may play an important part in establishing the logic relationship between codons and the quasi-amino acids during the course of life origination. According to Ma F et al (2003 J. Anhui Agricultural University 30 439), the corresponding relation and the excellent properties about amino acids code are very difficult to observe. The present paper shows that (ZU, ⊕, otimes) is a field. Furthermore, the operational results display that the codon tga has different property from other stop codons. In fact, in the mitochondrion from human and ox genomic codon, tga is just tryptophane, is not the stop codon like in other genetic code, it is the case of the Chen W C et al (2002 Acta Biophysica Sinica 18(1) 87). The present theory avoids some inexplicable events of the 20 kinds of amino acids code, in other words it solves the problem of 'the 64 codon assignments of mRNA to amino acids is probably completely wrong' proposed by Yang (2006 Progress in Modern Biomedicine 6 3).

  4. Particle Accelerators in China

    NASA Astrophysics Data System (ADS)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  5. Electromagnetic field-computation for particle accelerators, today and tomorrow

    SciTech Connect

    Turner, L.R.; Kettunen, L.

    1991-01-01

    In this paper, we first review the magnets needed in accelerators, then discuss computations for accelerator magnets performed with present codes, and finally describe a new volume integral code which shows promise, and should be suitable for parallel computation. 9 refs., 10 figs.

  6. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  7. SAC: Sheffield Advanced Code

    NASA Astrophysics Data System (ADS)

    Griffiths, Mike; Fedun, Viktor; Mumford, Stuart; Gent, Frederick

    2013-06-01

    The Sheffield Advanced Code (SAC) is a fully non-linear MHD code designed for simulations of linear and non-linear wave propagation in gravitationally strongly stratified magnetized plasma. It was developed primarily for the forward modelling of helioseismological processes and for the coupling processes in the solar interior, photosphere, and corona; it is built on the well-known VAC platform that allows robust simulation of the macroscopic processes in gravitationally stratified (non-)magnetized plasmas. The code has no limitations of simulation length in time imposed by complications originating from the upper boundary, nor does it require implementation of special procedures to treat the upper boundaries. SAC inherited its modular structure from VAC, thereby allowing modification to easily add new physics.

  8. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  9. Basic concepts in plasma accelerators.

    PubMed

    Bingham, Robert

    2006-03-15

    In this article, we present the underlying physics and the present status of high gradient and high-energy plasma accelerators. With the development of compact short pulse high-brightness lasers and electron and positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high-acceleration gradients. These include the plasma beat wave accelerator (PBWA) mechanism which uses conventional long pulse ( approximately 100 ps) modest intensity lasers (I approximately 10(14)-10(16) W cm(-2)), the laser wakefield accelerator (LWFA) which uses the new breed of compact high-brightness lasers (<1 ps) and intensities >10(18) W cm(-2), self-modulated laser wakefield accelerator (SMLWFA) concept which combines elements of stimulated Raman forward scattering (SRFS) and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches the plasma wakefield accelerator. In the ultra-high intensity regime, laser/particle beam-plasma interactions are highly nonlinear and relativistic, leading to new phenomenon such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm(-1) have been generated with monoenergetic particle beams accelerated to about 100 MeV in millimetre distances recorded. Plasma wakefields driven by both electron and positron beams at the Stanford linear accelerator centre (SLAC) facility have accelerated the tail of the beams.

  10. QR Codes

    ERIC Educational Resources Information Center

    Lai, Hsin-Chih; Chang, Chun-Yen; Li, Wen-Shiane; Fan, Yu-Lin; Wu, Ying-Tien

    2013-01-01

    This study presents an m-learning method that incorporates Integrated Quick Response (QR) codes. This learning method not only achieves the objectives of outdoor education, but it also increases applications of Cognitive Theory of Multimedia Learning (CTML) (Mayer, 2001) in m-learning for practical use in a diverse range of outdoor locations. When…

  11. LFSC - Linac Feedback Simulation Code

    SciTech Connect

    Ivanov, Valentin; /Fermilab

    2008-05-01

    The computer program LFSC (Code>) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output.

  12. US Accelerator R&D Program Toward Intensity Frontier Machines

    SciTech Connect

    Shiltsev, Vladimir

    2016-09-15

    The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centerpiece of the US domestic HEP program. Operation, upgrade and development of the accelerators for the near-term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators.

  13. The Phantom SPH code

    NASA Astrophysics Data System (ADS)

    Price, Daniel; Wurster, James; Nixon, Chris

    2016-05-01

    I will present the capabilities of the Phantom SPH code for global simulations of dust and gas in protoplanetary discs. I will present our new algorithms for simulating both small and large grains in discs, as well as our progress towards simulating evolving grain populations and coupling with radiation. Finally, I will discuss our recent applications to HL Tau and the physics of dust gap opening.

  14. Accelerating Around an Unbanked Curve

    DTIC Science & Technology

    2006-02-01

    FEB 2006 2. REPORT TYPE 3. DATES COVERED 00-00-2006 to 00-00-2006 4. TITLE AND SUBTITLE Accelerating Around an Unbanked Curve 5a. CONTRACT...December 2004 issue of TPT presented a problem concerning how a car should acceler-ate around an unbanked curve of constant radius r starting from rest...Accelerating Around an Unbanked Curve Carl E. Mungan, U.S. Naval Academy, Annapolis, MD 100 THE PHYSICS TEACHER ◆ Vol. 44, February 2006 The shapes

  15. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  16. Magnetically accelerated foils for shock wave experiments

    NASA Astrophysics Data System (ADS)

    Neff, Stephan; Ford, Jessica; Martinez, David; Plechaty, Christopher; Wright, Sandra; Presura, Radu

    2008-04-01

    The interaction of shock waves with inhomogeneous media is important in many astrophysical problems, e.g. the role of shock compression in star formation. Using scaled experiments with inhomogeneous foam targets makes it possible to study relevant physics in the laboratory, to better understand the mechanisms of shock compression and to benchmark astrophysical simulation codes. Experiments with flyer-generated shock waves have been performed on the Z machine in Sandia. The Zebra accelerator at the Nevada Terawatt Facility (NTF) allows for complementary experiments with high repetition rate. First experiments on Zebra demonstrated flyer acceleration to sufficiently high velocities (around 2 km/s) and that laser shadowgraphy can image sound fronts in transparent targets. Based on this, we designed an optimized setup to improve the flyer parameters (higher speed and mass) to create shock waves in transparent media. Once x-ray backlighting with the Leopard laser at NTF is operational, we will switch to foam targets with parameters relevant for laboratory astrophysics.

  17. Toward GPGPU accelerated human electromechanical cardiac simulations

    PubMed Central

    Vigueras, Guillermo; Roy, Ishani; Cookson, Andrew; Lee, Jack; Smith, Nicolas; Nordsletten, David

    2014-01-01

    In this paper, we look at the acceleration of weakly coupled electromechanics using the graphics processing unit (GPU). Specifically, we port to the GPU a number of components of Heart—a CPU-based finite element code developed for simulating multi-physics problems. On the basis of a criterion of computational cost, we implemented on the GPU the ODE and PDE solution steps for the electrophysiology problem and the Jacobian and residual evaluation for the mechanics problem. Performance of the GPU implementation is then compared with single core CPU (SC) execution as well as multi-core CPU (MC) computations with equivalent theoretical performance. Results show that for a human scale left ventricle mesh, GPU acceleration of the electrophysiology problem provided speedups of 164 × compared with SC and 5.5 times compared with MC for the solution of the ODE model. Speedup of up to 72 × compared with SC and 2.6 × compared with MC was also observed for the PDE solve. Using the same human geometry, the GPU implementation of mechanics residual/Jacobian computation provided speedups of up to 44 × compared with SC and 2.0 × compared with MC. © 2013 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons, Ltd. PMID:24115492

  18. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  19. OpenMP for Accelerators

    SciTech Connect

    Beyer, J C; Stotzer, E J; Hart, A; de Supinski, B R

    2011-03-15

    OpenMP [13] is the dominant programming model for shared-memory parallelism in C, C++ and Fortran due to its easy-to-use directive-based style, portability and broad support by compiler vendors. Similar characteristics are needed for a programming model for devices such as GPUs and DSPs that are gaining popularity to accelerate compute-intensive application regions. This paper presents extensions to OpenMP that provide that programming model. Our results demonstrate that a high-level programming model can provide accelerated performance comparable to hand-coded implementations in CUDA.

  20. Physical Processes of the Interaction Between Laser-Generated Plasma and Blast Wave Appearing in Laser-Driven In-Tube Accelerator Configuration

    SciTech Connect

    Sasoh, Akihiro; Mori, Koichi; Ohtani, Toshiro; Ohnishi, Naofumi; Ogino, Yosuke; Sawada, Keisuke

    2006-05-02

    Flow visualizations of the interaction between a laser-pulse-generated plasma and a shock wave driven by it have been experimentally conducted. The configuration of the experimental set-up corresponds to the laser-driven, in-tube accelerator. Primary-mode deformation of the plasma is governed by Richtmyer-Meshkov instability which is produced by the vector product between the pressure and density gradients, which in turn correspond to a reflected shock wave and to the plasma, respectively. Higher-mode contact surface deformations are supposedly originated in Rayleigh-Taylor instability in the shrinkage phase of the plasma, and is enhanced due to the passage of the reflected shock wave.

  1. Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

    SciTech Connect

    Mark, J.W.K.

    1982-03-22

    Calculations suggest that experiments relating to disk heating, as well as beam deposition, focusing and transport can be performed within the context of current design proposals for accelerator test-facilities. Since the test-facilities have lower ion kinetic energy and beam pulse power as compared to reactor drivers, we achieve high-beam intensities at the focal spot by using short focal distance and properly designed beam optics. In this regard, the low beam emittance of suggested multi-beam designs are very useful. Possibly even higher focal spot brightness could be obtained by plasma lenses which involve external fields on the beam which is stripped to a higher charge state by passing through a plasma cell. Preliminary results suggest that intensities approx. 10/sup 13/ - 10/sup 14/ W/cm/sup 2/ are achievable. Given these intensities, deposition experiments with heating of disks to greater than a million degrees Kelvin (100 eV) are expected.

  2. MANTRA: An Integral Reactor Physics Experiment to Infer Actinide Capture Cross-sections from Thorium to Californium with Accelerator Mass Spectrometry

    SciTech Connect

    G. Youinou; C. McGrath; G. Imel; M. Paul; R. Pardo; F. Kondev; M. Salvatores; G. Palmiotti

    2011-08-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectrometry technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am, 244Cm and 248Cm.

  3. Electron Acceleration by Transient Ion Foreshock Phenomena

    NASA Astrophysics Data System (ADS)

    Wilson, L. B., III; Turner, D. L.

    2015-12-01

    Particle acceleration is a topic of considerable interest in space, laboratory, and astrophysical plasmas as it is a fundamental physical process to all areas of physics. Recent THEMIS [e.g., Turner et al., 2014] and Wind [e.g., Wilson et al., 2013] observations have found evidence for strong particle acceleration at macro- and meso-scale structures and/or pulsations called transient ion foreshock phenomena (TIFP). Ion acceleration has been extensively studied, but electron acceleration has received less attention. Electron acceleration can arise from fundamentally different processes than those affecting ions due to differences in their gyroradii. Electron acceleration is ubiquitous, occurring in the solar corona (e.g., solar flares), magnetic reconnection, at shocks, astrophysical plasmas, etc. We present new results analyzing the dependencies of electron acceleration on the properties of TIFP observed by the THEMIS spacecraft.

  4. Overview of the WARP code and studies of transverse resonance effects

    SciTech Connect

    Friedman, A.

    1998-11-01

    Two papers presented at the Shelter Island workshop are very briefly summarized here, in view of recent publications elsewhere. The WARP code, developed for Heavy-Ion beam-driven inertial confinement Fusion (HIF) accelerator studies, combines features of a particle-in-cell plasma simulation and an accelerator tracking program. Its methods and architecture have been developed for efficiency both in detailed simulation of individual machine sections and in long-time beam tracking. The transverse {open_quotes}slice{close_quotes} model in the code has been applied to the study of transverse resonance effects associated with quadrupole strength errors. These simulations confirm that rapid passage through a resonance can reduce the associated mismatch and emittance growth. References to published details and to other sources of information are supplied. {copyright} {ital 1998 American Institute of Physics.}

  5. Accelerator Technology Program. Status report, January-September 1983

    SciTech Connect

    Jameson, R.A.

    1984-07-01

    This report presents highlights of major projects in the Accelerator Technology Division of the Los Alamos National Laboratory. The first section deals with the Fusion Materials Irradiation Test Facility's 2-MeV accelerator on which tests began in May, as scheduled. Then, activities are reported on beam dynamics, inertial fusion, structure development, the racetrack microtron, the CERN high-energy physics experiment NA-12, and LAMPF II. The Proton Storage Ring is discussed next, with emphasis on the computer control system, diagnostics interfacing, and theoretical support. Other sections summarize progress on a portable radiographic linac, developments on the klystron code, and on permanent magnets. Activities of the Theory and Simulation Group are outlined next, followed by discussion of the oscillator experiment and the energy-recovery experiment in the free electron laser project. The last section reports on the accelerator test stand. An unusual and very satisfying activity for the Division was the hosting of the 1983 Particle Accelerator Conference in Santa Fe, March 21-23, 1983. The conference had the largest attendance ever, with 895 registrants, 61 invited papers, and 521 contributed papers.

  6. Visions for the future of particle accelerators

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2013-10-01

    The ambitions of accelerator based science, technology and applications far exceed the present accelerator possibilities. Accelerator science and technology is one of a key enablers of the developments in the particle physic, photon physics and also applications in medicine and industry. The paper presents a digest of the research results and visions for the future in the domain of accelerator science and technology in Europe, shown during the final fourth annual meeting of the EuCARD - European Coordination of Accelerator Research and Development. The conference concerns building of the research infrastructure, including advanced photonic and electronic systems for servicing large high energy physics experiments. There are debated a few basic groups of such systems like: measurement - control networks of large geometrical extent, multichannel systems for large amounts of metrological data acquisition, precision photonic networks of reference time, frequency and phase distribution. The main subject is however the vision for the future of particle accelerators and next generation light sources.

  7. Improvement of the WBC calibration of the Internal Dosimetry Laboratory of the CDTN/CNEN using the physical phantom BOMAB and MCNPX code.

    PubMed

    Paiva, Fernanda Guerra; Oliveira, Arno Heeren de; Mendes, Bruno Melo; Pinto, Jacqueline Rosária; Filho, Nelson do Nascimento A; Dantas, Bernardo Maranhão; Dantas, Ana Letícia A; Silva, Teógenes Augusto da; Lacerda, Marco Aurélio de Sousa; Fonseca, Telma Cristina Ferreira

    2016-11-01

    The Laboratory of Internal Dosimetry of the Center for Development of Nuclear Technology (LDI/CDTN) is responsible for routine internal monitoring of occupationally exposed individuals. The determination of photon emitting radionuclides in the human body requires calibration of the detector in specific counting geometries. The calibration process uses physical phantoms containing certified activities of the radionuclides of interest. The objective of this work was to obtain calibration efficiency curves of the Whole Body Counter in operation at the LDI/CDTN using a BOMAB physical phantom and Monte Carlo simulations.

  8. Final Progress Report - Heavy Ion Accelerator Theory and Simulation

    SciTech Connect

    Haber, Irving

    2009-10-31

    The use of a beam of heavy ions to heat a target for the study of warm dense matter physics, high energy density physics, and ultimately to ignite an inertial fusion pellet, requires the achievement of beam intensities somewhat greater than have traditionally been obtained using conventional accelerator technology. The research program described here has substantially contributed to understanding the basic nonlinear intense-beam physics that is central to the attainment of the requisite intensities. Since it is very difficult to reverse intensity dilution, avoiding excessive dilution over the entire beam lifetime is necessary for achieving the required beam intensities on target. The central emphasis in this research has therefore been on understanding the nonlinear mechanisms that are responsible for intensity dilution and which generally occur when intense space-charge-dominated beams are not in detailed equilibrium with the external forces used to confine them. This is an important area of study because such lack of detailed equilibrium can be an unavoidable consequence of the beam manipulations such as acceleration, bunching, and focusing necessary to attain sufficient intensity on target. The primary tool employed in this effort has been the use of simulation, particularly the WARP code, in concert with experiment, to identify the nonlinear dynamical characteristics that are important in practical high intensity accelerators. This research has gradually made a transition from the study of idealized systems and comparisons with theory, to study the fundamental scaling of intensity dilution in intense beams, and more recently to explicit identification of the mechanisms relevant to actual experiments. This work consists of two categories; work in direct support beam physics directly applicable to NDCX and a larger effort to further the general understanding of space-charge-dominated beam physics.

  9. Aeroacoustic Prediction Codes

    NASA Technical Reports Server (NTRS)

    Gliebe, P; Mani, R.; Shin, H.; Mitchell, B.; Ashford, G.; Salamah, S.; Connell, S.; Huff, Dennis (Technical Monitor)

    2000-01-01

    This report describes work performed on Contract NAS3-27720AoI 13 as part of the NASA Advanced Subsonic Transport (AST) Noise Reduction Technology effort. Computer codes were developed to provide quantitative prediction, design, and analysis capability for several aircraft engine noise sources. The objective was to provide improved, physics-based tools for exploration of noise-reduction concepts and understanding of experimental results. Methods and codes focused on fan broadband and 'buzz saw' noise and on low-emissions combustor noise and compliment work done by other contractors under the NASA AST program to develop methods and codes for fan harmonic tone noise and jet noise. The methods and codes developed and reported herein employ a wide range of approaches, from the strictly empirical to the completely computational, with some being semiempirical analytical, and/or analytical/computational. Emphasis was on capturing the essential physics while still considering method or code utility as a practical design and analysis tool for everyday engineering use. Codes and prediction models were developed for: (1) an improved empirical correlation model for fan rotor exit flow mean and turbulence properties, for use in predicting broadband noise generated by rotor exit flow turbulence interaction with downstream stator vanes: (2) fan broadband noise models for rotor and stator/turbulence interaction sources including 3D effects, noncompact-source effects. directivity modeling, and extensions to the rotor supersonic tip-speed regime; (3) fan multiple-pure-tone in-duct sound pressure prediction methodology based on computational fluid dynamics (CFD) analysis; and (4) low-emissions combustor prediction methodology and computer code based on CFD and actuator disk theory. In addition. the relative importance of dipole and quadrupole source mechanisms was studied using direct CFD source computation for a simple cascadeigust interaction problem, and an empirical combustor

  10. Review of ion accelerators

    SciTech Connect

    Alonso, J.

    1990-06-01

    The field of ion acceleration to higher energies has grown rapidly in the last years. Many new facilities as well as substantial upgrades of existing facilities have extended the mass and energy range of available beams. Perhaps more significant for the long-term development of the field has been the expansion in the applications of these beams, and the building of facilities dedicated to areas outside of nuclear physics. This review will cover many of these new developments. Emphasis will be placed on accelerators with final energies above 50 MeV/amu. Facilities such as superconducting cyclotrons and storage rings are adequately covered in other review papers, and so will not be covered here.

  11. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.; Saadatmand, K.

    1992-09-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth`s magnetic field and travel in straight lines unless they enter the earth`s atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  12. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V. ); Connolly, R.; Weiss, R. (Gr

    1992-01-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth's magnetic field and travel in straight lines unless they enter the earth's atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  13. Transversal Clifford gates on folded surface codes

    SciTech Connect

    Moussa, Jonathan E.

    2016-10-12

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surface codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. Lastly, the specific application of these codes to universal quantum computation based on qubit fusion is also discussed.

  14. Transversal Clifford gates on folded surface codes

    DOE PAGES

    Moussa, Jonathan E.

    2016-10-12

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surfacemore » codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. Lastly, the specific application of these codes to universal quantum computation based on qubit fusion is also discussed.« less

  15. Transversal Clifford gates on folded surface codes

    NASA Astrophysics Data System (ADS)

    Moussa, Jonathan E.

    2016-10-01

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surface codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. The specific application of these codes to universal quantum computation based on qubit fusion is also discussed.

  16. Accelerator Technology Division progress report, FY 1992

    SciTech Connect

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  17. Accelerate Climate Models with the IBM Cell Processor

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Duffy, D.; Clune, T.; Williams, S.; Suarez, M.; Halem, M.

    2008-12-01

    Ever increasing model resolutions and physical processes in climate models demand continual computing power increases. The IBM Cell processor's order-of- magnitude peak performance increase over conventional processors makes it very attractive for fulfilling this requirement. However, the Cell's characteristics: 256KB local memory per SPE and the new low-level communication mechanism, make it very challenging to port an application. We selected the solar radiation component of the NASA GEOS-5 climate model, which: (1) is representative of column physics components (~50% total computation time), (2) has a high computational load relative to data traffic to/from main memory, and (3) performs independent calculations across multiple columns. We converted the baseline code (single-precision, Fortran code) to C and ported it to an IBM BladeCenter QS20, manually SIMDizing 4 independent columns, and found that a Cell with 8 SPEs can process more than 3000 columns per second. Compared with the baseline results, the Cell is ~6.76x, ~8.91x, ~9.85x faster than a core on Intel's Xeon Woodcrest, Dempsey, and Itanium2 respectively. Our analysis shows that the Cell could also speed up the dynamics component (~25% total computation time). We believe this dramatic performance improvement makes the Cell processor very competitive, at least as an accelerator. We will report our experience in porting both the C and Fortran codes and will discuss our work in porting other climate model components.

  18. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  19. Tandem Mirror Reactor Systems Code (Version I)

    SciTech Connect

    Reid, R.L.; Finn, P.A.; Gohar, M.Y.; Barrett, R.J.; Gorker, G.E.; Spampinaton, P.T.; Bulmer, R.H.; Dorn, D.W.; Perkins, L.J.; Ghose, S.

    1985-09-01

    A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost.

  20. CHOLLA: A New Massively Parallel Hydrodynamics Code for Astrophysical Simulation

    NASA Astrophysics Data System (ADS)

    Schneider, Evan E.; Robertson, Brant E.

    2015-04-01

    We present Computational Hydrodynamics On ParaLLel Architectures (Cholla ), a new three-dimensional hydrodynamics code that harnesses the power of graphics processing units (GPUs) to accelerate astrophysical simulations. Cholla models the Euler equations on a static mesh using state-of-the-art techniques, including the unsplit Corner Transport Upwind algorithm, a variety of exact and approximate Riemann solvers, and multiple spatial reconstruction techniques including the piecewise parabolic method (PPM). Using GPUs, Cholla evolves the fluid properties of thousands of cells simultaneously and can update over 10 million cells per GPU-second while using an exact Riemann solver and PPM reconstruction. Owing to the massively parallel architecture of GPUs and the design of the Cholla code, astrophysical simulations with physically interesting grid resolutions (≳2563) can easily be computed on a single device. We use the Message Passing Interface library to extend calculations onto multiple devices and demonstrate nearly ideal scaling beyond 64 GPUs. A suite of test problems highlights the physical accuracy of our modeling and provides a useful comparison to other codes. We then use Cholla to simulate the interaction of a shock wave with a gas cloud in the interstellar medium, showing that the evolution of the cloud is highly dependent on its density structure. We reconcile the computed mixing time of a turbulent cloud with a realistic density distribution destroyed by a strong shock with the existing analytic theory for spherical cloud destruction by describing the system in terms of its median gas density.