Science.gov

Sample records for accelerator structure development

  1. Accelerator Structure Development for NLC/GLC

    SciTech Connect

    Wang, J

    2004-03-05

    The NLC (Next Linear Collider) and GLC (Global Linear Collider) [1,2] are e{sup +}e{sup -} linear collider proposals based on room-temperature accelerator technology--so called ''warm machines'' in comparison with the TESLA ''cold machine'' that is based on superconducting accelerator technology. There have been two major challenges in developing X-band (11.4 GHz) accelerator structures for the GLC/NLC. The first is to demonstrate stable, long-term operation at the high gradient (65 MV/m) that is required to optimize the machine cost. The second is to strongly suppress the beam induced long-range wakefields, which is required to achieve high luminosity. The development of high gradient structures has been a high priority in recent years. Nearly thirty X-band structures with various rf parameters, cavity shapes and coupler types have been fabricated and tested since 2000. This program has been a successful collaborative effort among groups at SLAC, KEK, FNAL and other labs. A summary of the main achievements and experiences are presented in this paper as well as a status report on the structure design, high power performance, manufacturing techniques, and other structure related issues.

  2. Development of X-Band Dielectric-Loaded Accelerating Structures

    SciTech Connect

    Gold, S. H.; Jing, C.; Kanareykin, A.; Gai, W.; Konecny, R.; Power, J. G.; Kinkead, A. K.

    2010-11-04

    This paper presents a progress report on the development and testing of X-band dielectric-loaded accelerating structures. Recent tests on several quartz DLA structures with different inner diameters are reported. Designs for gap-free DLA structures are presented. Also, planned new experiments are discussed, including higher gradient traveling-wave and standing-wave structures and special grooved structures for multipactor suppression.

  3. Research and Development for Ultra-High Gradient Accelerator Structures

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami G.; Dolgashev, Valery; Higashi, Yasuo; Spataro, Bruno

    2010-11-01

    Research on the basic physics of high-gradient, high frequency accelerator structures and the associated RF/microwave technology are essential for the future of discovery science, medicine and biology, energy and environment, and national security. We will review the state-of-the-art for the development of high gradient linear accelerators. We will present the research activities aimed at exploring the basic physics phenomenon of RF breakdown. We present the experimental results of a true systematic study in which the surface processing, geometry, and materials of the structures have been varied, one parameter at a time. The breakdown rate or alternatively, the probability of breakdown/pulse/meter has been recorded for different operating parameters. These statistical data reveal a strong dependence of breakdown probability on surface magnetic field, or alternatively on surface pulsed heating. This is in contrast to the classical view of electric field dependence.

  4. 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.

  5. Latest Development in Superconducting RF Structures for beta=1 Particle Acceleration

    SciTech Connect

    Peter Kneisel

    2006-06-26

    Superconducting RF technology is since nearly a decade routinely applied to different kinds of accelerating devices: linear accelerators, storage rings, synchrotron light sources and FEL's. With the technology recommendation for the International Linear Collider (ILC) a year ago, new emphasis has been placed on improving the performance of accelerating cavities both in Q-value and in accelerating gradients with the goal to achieve performance levels close to the fundamental limits given by the material parameters of the choice material, niobium. This paper will summarize the challenges to SRF technology and will review the latest developments in superconducting structure design. Additionally, it will give an overview of the newest results and will report on the developments in alternative materials and technologies.

  6. Update on the development of externally powered dielectric-loaded accelerating structures.

    SciTech Connect

    Jing, C.; Gai, W.; Konecny, R.; Power, J. G.; Liu, W.; Kanareykin, A.; Gold, S.; Kinkead, A. K.; High Energy Physics; EuclidTechlabs,; Naval Research Lab.; Icarus Research

    2009-01-01

    We report on recent progress in a program to develop an RF-driven Dielectric-Loaded Accelerating (DLA) structure, capable of supporting high gradient acceleration. Previous high power tests revealed that the earlier DLA structures suffered from multipactor and arcing at the dielectric joint. A few new DLA structures have been designed to alleviate this limitation including the coaxial coupler based DLA structure and the clamped DLA structure. These structures were recently fabricated and high power tested at the NRL X-band Magnicon facility. Results show the multipactor can be reduced by the TiN coating on the dielectric surface. Gradient of 15 MV/m has also been tested without dielectric breakdown in the test of the clamped DLA structure. Detailed results are reported, and future plans discussed.

  7. Update on the Development of Externally Powered Dielectric-Loaded Accelerating Structures

    SciTech Connect

    Jing, C.; Kanareykin, A.; Gai, W.; Konecny, R.; Power, J. G.; Liu, W.; Gold, S. H.; Kinkead, A. K.

    2009-01-22

    We report on recent progress in a program to develop an RF-driven Dielectric-Loaded Accelerating (DLA) structure, capable of supporting high gradient acceleration. Previous high power tests revealed that the earlier DLA structures suffered from multipactor and arcing at the dielectric joint. A few new DLA structures have been designed to alleviate this limitation including the coaxial coupler based DLA structure and the clamped DLA structure. These structures were recently fabricated and high power tested at the NRL X-band Magnicon facility. Results show the multipactor can be reduced by the TiN coating on the dielectric surface. Gradient of 15 MV/m has also been tested without dielectric breakdown in the test of the clamped DLA structure. Detailed results are reported, and future plans discussed.

  8. The foxhole accelerating structure

    SciTech Connect

    Fernow, R.C.; Claus, J.

    1992-07-17

    This report examines some properties of a new type of open accelerating structure. It consists of a series of rectangular cavities, which we call foxholes, joined by a beam channel. The power for accelerating the particles comes from an external radiation source and enters the cavities through their open upper surfaces. Analytic and computer calculations are presented showing that the foxhole is a suitable structure for accelerating relativistic electrons.

  9. Advanced accelerator theory development

    SciTech Connect

    Sampayan, S.E.; Houck, T.L.; Poole, B.; Tishchenko, N.; Vitello, P.A.; Wang, I.

    1998-02-09

    A new accelerator technology, the dielectric wall accelerator (DWA), is potentially an ultra compact accelerator/pulsed power driver. This new accelerator relies on three new components: the ultra-high gradient insulator, the asymmetric Blumlein and low jitter switches. In this report, we focused our attention on the first two components of the DWA system the insulators and the asymmetric Blumlein. First, we sought to develop the necessary design tools to model and scale the behavior of the high gradient insulator. To perform this task we concentrated on modeling the discharge processes (i.e., initiation and creation of the surface discharge). In addition, because these high gradient structures exhibit favorable microwave properties in certain accelerator configurations, we performed experiments and calculations to determine the relevant electromagnetic properties. Second, we performed circuit modeling to understand energy coupling to dynamic loads by the asymmetric Blumlein. Further, we have experimentally observed a non-linear coupling effect in certain asymmetric Blumlein configurations. That is, as these structures are stacked into a complete module, the output voltage does not sum linearly and a lower than expected output voltage results. Although we solved this effect experimentally, we performed calculations to understand this effect more fully to allow better optimization of this DWA pulse-forming line system.

  10. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  11. Dielectric assist accelerating structure

    NASA Astrophysics Data System (ADS)

    Satoh, D.; Yoshida, M.; Hayashizaki, N.

    2016-01-01

    A higher-order TM02 n mode accelerating structure is proposed based on a novel concept of dielectric loaded rf cavities. This accelerating structure consists of ultralow-loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure. Unlike conventional dielectric loaded accelerating structures, most of the rf power is stored in the vacuum space near the beam axis, leading to a significant reduction of the wall loss, much lower than that of conventional normal-conducting linac structures. This allows us to realize an extremely high quality factor and a very high shunt impedance at room temperature. A simulation of a 5 cell prototype design with an existing alumina ceramic indicates an unloaded quality factor of the accelerating mode over 120 000 and a shunt impedance exceeding 650 M Ω /m at room temperature.

  12. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

    SciTech Connect

    Byer, Robert L.

    2013-11-07

    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  13. Development of a dual-layered dielectric-loaded accelerating structure

    NASA Astrophysics Data System (ADS)

    Jing, Chunguang; Kanareykin, Alexei; Kazakov, Sergey; Liu, Wanming; Nenasheva, Elizaveta; Schoessow, Paul; Gai, Wei

    2008-09-01

    rf Power attenuation is a critical problem in the development of dielectric-loaded structures for particle acceleration. In a previous paper [C. Jing, W. Liu, W. Gai, J. Power, T. Wong, Nucl. Instr. Meth. A 539 (2005) 445] we suggested the use of a Multilayer Dielectric-Loaded Accelerating Structure (MDLA) as a possible approach for reducing the rf losses in a single layer device. The MDLA is based on the principle of Bragg reflection familiar from optics that is used to partially confine the fields inside the dielectric layers and reduce the wall current losses at the outer boundary. We report here on the design, construction and testing of a prototype X-band double-layer structure (2DLA). The measurements show an rf power attenuation for the 2DLA more than ten times smaller than that of a comparable single-layer structure, in good agreement with the analytic results. Testing and operation of MDLAs also requires efficient power coupling from test equipment or rf power systems to the device. We describe the design and construction of two novel structures: a TM 03 mode launcher for cold testing and a power coupler for planned high-gradient experiments.

  14. Accelerated Management Development

    ERIC Educational Resources Information Center

    Munn, Kenn

    1974-01-01

    Western Electric's accelerated management development program for hand picked college graduate students consists of a high risk training project in which the management candidate accomplishes his task or is terminated. The success of such projects puts candidates in third level management in seven years or half the normal time. (DS)

  15. Development of a Laser-Powered Dielectric Structure-Based Accelerator as a Stand-Alone Particle Source

    NASA Astrophysics Data System (ADS)

    Yoder, R. B.; Travish, G.; Arab, E. R.; Fong, D.; Hoyer, Z.; Lacroix, U. H.; Vartanian, N.; Rosenzweig, J. B.

    2010-11-01

    An experimental program to develop and build a dielectric-based slab-symmetric structure (the micro-accelerator platform, or MAP) for generating and accelerating low-energy electrons is underway at UCLA and Manhattanville College. This optical acceleration structure is effectively a resonant cavity powered by a side-coupled laser, and has applications as a radiation source for medicine or industry. We present recent experimental and computational results on the accelerator, and progress toward its incorporation into a self-contained particle source. Such a particle source would incorporate a micron-scale electron emitter and a non-relativistic capture region to enable self-injection into the synchronous field within the accelerator. A prototype of the accelerator itself has been constructed from candidate dielectric materials using micromanufacturing techniques; the current status of the testing program is described. A novel electron emitter incorporating pyroelectric crystals with field-enhancing tips has been demonstrated to produce steady currents; the results are dependent on tip geometry, and appear suitable for injection into a microstructure. Extension of the MAP concept to non-relativistic velocities, as in the stand-alone source, requires a tapered structure that gives rise to numerous complications including beam defocusing and manufacturing challenges; approaches for addressing these complications are mentioned.

  16. CVD Diamond Dielectric Accelerating Structures

    SciTech Connect

    Schoessow, P.; Kanareykin, A.; Gat, R.

    2009-01-22

    The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerating structures: high RF breakdown field, extremely low dielectric losses and the highest available thermoconductive coefficient. Using chemical vapor deposition (CVD) cylindrical diamond structures have been manufactured with dimensions corresponding to fundamental TM{sub 01} mode frequencies in the GHz to THz range. Surface treatments are being developed to reduce the secondary electron emission (SEE) coefficient below unity to reduce the possibility of multipactor. The diamond CVD cylindrical waveguide technology developed here can be applied to a variety of other high frequency, large-signal applications.

  17. Accelerator structure work for NLC

    SciTech Connect

    Miller, R.H.; Adolphsen, C.; Bane, K.L.F.; Deruyter, H.; Farkas, Z.D.; Hoag, H.A.; Holtkamp, N.; Lavine, T.; Loew, G.A.; Nelson, E.M.; Palmer, R.B.; Paterson, J.M.; Ruth, R.D.; Thompson, K.A.; Vlieks, A.; Wang, J.W.; Wilson, P.B.; Gluckstern, R.; Ko, K.; Kroll, N. |

    1992-07-01

    The NLC design achieves high luminosity with multiple bunches in each RF pulse. Acceleration of a train of bunches without emittance growth requires control of long range dipole wakefields. SLAC is pursuing a structure design which suppresses the effect of wakefields by varying the physical dimensions of successive cells of the disk-loaded traveling wave structure in a manner which spreads the frequencies of the higher mode while retaining the synchronism between the electrons and the accelerating mode. The wakefields of structures incorporating higher mode detuning have been measured at the Accelerator Test Facility at Argonne. Mechanical design and brazing techniques which avoid getting brazing alloy into the interior of the accelerator are being studied. A test facility for high-power testing of these structures is complete and high power testing has begun.

  18. Development of millimeter-wave accelerating structures using precision metal forming technology

    SciTech Connect

    2003-06-03

    High gradients in radio-frequency (RF) driven accelerators require short wavelengths that have the concomitant requirements of small feature size and high tolerances, 1-2 {micro}m for millimeter wavelengths. Precision metal-forming stampling has the promise of meeting those tolerances with high production rates. This STI will evaluate that promise.

  19. Final Report on "Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz"

    SciTech Connect

    Gold, Steven H.

    2013-10-13

    This is the final report on the research program ?Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz,? which was carried out by the Naval Research Laboratory (NRL) under Interagency Agreement DE?AI02?01ER41170 with the Department of Energy. The period covered by this report is 15 July 2010 ? 14 July 2013. The program included two principal tasks. Task 1 involved a study of the key physics issues related to the use of high gradient dielectric-loaded accelerating (DLA) structures in rf linear accelerators and was carried out in collaboration with Argonne National Laboratory (ANL) and Euclid Techlabs LLC. Task 2 involved a study of high power active microwave pulse compressors and was carried out in collaboration with Omega-P, Inc. and the Institute of Applied Physics of the Russian Academy of Sciences in Nizhny Novgorod. The studies under Task 1 were focused on rf-induced multipactor and breakdown in externally driven DLA structures at the 200-ns timescale. Suppression of multipactor and breakdown are essential to the practical application of dielectric structures in rf linear accelerators. The structures that were studied were developed by ANL and Euclid Techlabs and their performance was evaluated at high power in the X-band Magnicon Laboratory at NRL. Three structures were designed, fabricated, and tested, and the results analyzed in the first two years of the program: a clamped quartz traveling-wave (TW) structure, a externally copper-coated TW structure, and an externally copper-coated dielectric standing-wave (SW) structure. These structures showed that rf breakdown could be largely eliminated by eliminating dielectric joints in the structures, but that the multipactor loading was omnipresent. In the third year of the program, the focus of the program was on multipactor suppression using a strong applied axial magnetic field, as proposed by Chang et al. [C. Chang et al., J. Appl. Phys. 110, 063304 (2011).], and a

  20. Multi-Mode Cavity Accelerator Structure

    SciTech Connect

    Jiang, Yong; Hirshfield, Jay Leonard

    2016-11-10

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10-7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise ΔT. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field Esurmax< 260 MV/m and pulsed surface heating ΔTmax< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power—as compared with operation at the same acceleration gradient using only the fundamental mode.

  1. Vibrational Stability of NLC Linac accelerating structure

    SciTech Connect

    Le Pimpec, Frederic

    2002-09-25

    The vibration of components of the NLC linac, such as accelerating structures and girders, is being studied both experimentally and analytically. Various effects are being considered including structural resonances and vibration caused by cooling water in the accelerating structure. This paper reports the status of ongoing work.

  2. The fabrication of millimeter-wavelength accelerating structures

    SciTech Connect

    Chou, P.J.; Bowden, G.B.; Copeland, M.R.

    1996-11-01

    There is a growing interest in the development of high gradient ({ge} 1 GeV/m) accelerating structures. The need for high gradient acceleration based on current microwave technology requires the structures to be operated in the millimeter wavelength. Fabrication of accelerating structures at millimeter scale with sub-micron tolerances poses great challenges. The accelerating structures impose strict requirements on surface smoothness and finish to suppress field emission and multipactor effects. Various fabrication techniques based on conventional machining and micromachining have been evaluated and tested. These will be discussed and measurement results presented.

  3. Progress Toward NLC/GLC Prototype Accelerator Structures

    SciTech Connect

    Wang, J

    2004-09-13

    The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and design of HOM couplers and fundamental mode couplers, optimized accelerator cavities as well as plans for future structures.

  4. Embryonic development during chronic acceleration

    NASA Technical Reports Server (NTRS)

    Smith, A. H.; Abbott, U. K.

    1982-01-01

    Experiments carried out on chicken eggs indicate that the embryo is affected during very early development, especially over the first four days, and during hatching. In the first four days, the brain develops as well as the anlage for all other organs. In addition, the heart commences to function and the extraembryonic membranes that compartmentalize the egg contents form. The latter require an appreciable extension and folding of tissue which may be disrupted by the mechanical load. Observations of embryonic abnormalities that occur during chronic acceleration suggest an inhibition of development of the axial skeleton, which is rarely seen otherwise, a general retardation of embryonic growth, and circulatory problems. The final stages of development (after 18 days) involve the uptake of fluids, the transition to aerial respiration, and the reorientation of the embryo into a normal hatching position. At 4 G mortality is very high during this period, with a majority of embryos failing to reorient into the normal hatching position.

  5. UCLA accelerator research and development

    SciTech Connect

    Cline, D.B.

    1992-01-01

    This progress report covers work supported by the above DOE grant over the period November 1, 1991 to July 31, 1992. The work is a program of experimental and theoretical studies in advanced particle accelerator research and development for high energy physics applications. The program features research at particle beam facilities in the United States and includes research on novel high power sources, novel focussing systems (e.g. plasma lens), beam monitors, novel high brightness, high current gun systems, and novel flavor factories in particular the {phi} Factory.

  6. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin M.

    2007-08-22

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  7. Micromechanical structures and microelectronics for acceleration sensing

    NASA Astrophysics Data System (ADS)

    Davies, Brady R.; Montague, Stephen; Smith, James H.; Lemkin, Mark

    1997-09-01

    MEMS is an enabling technology that may provide low-cost devices capable of sensing motion in a reliable and accurate manner. This paper describes work in MEMS accelerometer development at Sandia National Laboratories. This work leverages a process for integrating both the micromechanical structures and microelectronics circuitry of a MEMS accelerometer on the same chip. The design and test results of an integrated MEMS high-g accelerometer will be detailed. Additionally a design for a high-g fuse component (low-G or approximately equals 25 G accelerometer) will be discussed in the paper (where 1 G approximately equals 9.81 m/s). In particular, a design team at Sandia was assembled to develop a new micromachined silicon accelerometer which would be capable of surviving and measuring high-g shocks. Such a sensor is designed to be cheaper and more reliable than currently available sensors. A promising design for a suspended plate mass sensor was developed and the details of that design along with test data will be documented in the paper. Future development in this area at Sandia will focus on implementing accelerometers capable of measuring 200 kilo-g accelerations. Accelerometer development at Sandia will also focus on multi-axis acceleration measurement with integrated microelectronics.

  8. Advanced accelerating structures and their interaction with electron beams.

    SciTech Connect

    Gai, W.; High Energy Physics

    2008-01-01

    In this paper, we give a brief description of several advanced accelerating structures, such as dielectric loaded waveguides, photonic band gap, metamaterials and improved iris-loaded cavities. We describe wakefields generated by passing high current electron beams through these structures, and applications of wakefields to advanced accelerator schemes. One of the keys to success for high gradient wakefield acceleration is to develop high current drive beam sources. As an example, the high current RF photo injector at the Argonne Wakefield Accelerator, passed a {approx}80 nC electron beam through a high gradient dielectric loaded structure to achieve a 100 MV/m gradient. We will summarize recent related experiments on beam-structure interactions and also discuss high current electron beam generation and propagation and their applications to wakefield acceleration.

  9. Advanced Accelerating Structures and Their Interaction with Electron Beams

    SciTech Connect

    Gai Wei

    2009-01-22

    In this paper, we give a brief description of several advanced accelerating structures, such as dielectric loaded waveguides, photonic band gap, metamaterials and improved iris-loaded cavities. We describe wakefields generated by passing high current electron beams through these structures, and applications of wakefields to advanced accelerator schemes. One of the keys to success for high gradient wakefield acceleration is to develop high current drive beam sources. As an example, the high current RF photo injector at the Argonne Wakefield Accelerator, passed a {approx}80 nC electron beam through a high gradient dielectric loaded structure to achieve a 100 MV/m gradient. We will summarize recent related experiments on beam-structure interactions and also discuss high current electron beam generation and propagation and their applications to wakefield acceleration.

  10. Cluster Multipoint Observations of the Spatial Structure and Time Development of Auroral Acceleration Region Field-aligned Current Systems, Potentials, and Plasma

    NASA Astrophysics Data System (ADS)

    Hull, A. J.; Chaston, C. C.; Fillingim, M. O.; Frey, H. U.; Bonnell, J. W.; Mozer, F.; Goldstein, M. L.

    2014-12-01

    The auroral acceleration region is an integral part of the magnetosphere-ionosphere electrodynamic system, and plays a key role in the transport of plasma and energy between Earth and space. This region is embedded with field-aligned currents that couple the magnetosphere to the ionosphere and is where parallel electric fields form that accelerate plasma to and from these regions. Though considerable progress has been made, the complex interplay between field-aligned current system formation, the development of parallel electric fields, changes in the plasma constituents, and auroral emissions consequences are not fully understood. The Cluster mission is well suited for studying the structure and dynamics of the auroral acceleration region. Over its lifetime, Cluster has sampled much of this region with closely spaced probes enabling the distinction between temporal effects from spatial variations. Moreover, this data when combined with auroral images from IMAGE or THEMIS GBO-ASI enable an assessment of the auroral emission response to spatial morphology and temporal development of structures seeded in the auroral acceleration region. In this study we present a survey of Cluster multi-point traversals within and just above the auroral acceleration region (≤ 3 Re altitude). In particular we highlight the spatial morphology and developmental sequence of auroral acceleration current systems, potentials and plasma constituents, with the aim of identifying controlling factors, and assessing ionospheric consequences under different conditions. Our results suggest that the "Alfvénic" activity may be an important precursor and perhaps may be playing an essential role in the development of "quasi-static" current systems during quiet and substorm active times. Such events are generally the result of an injection mediated process at or near the plasma sheet boundary layer, resulting in the local expansion of the plasma sheet. Key features of the conversion from Alfv

  11. High-performance computing in accelerating structure design and analysis

    NASA Astrophysics Data System (ADS)

    Li, Zenghai; Folwell, Nathan; Ge, Lixin; Guetz, Adam; Ivanov, Valentin; Kowalski, Marc; Lee, Lie-Quan; Ng, Cho-Kuen; Schussman, Greg; Stingelin, Lukas; Uplenchwar, Ravindra; Wolf, Michael; Xiao, Liling; Ko, Kwok

    2006-03-01

    Future high-energy accelerators such as the Next Linear Collider (NLC) will accelerate multi-bunch beams of high current and low emittance to obtain high luminosity, which put stringent requirements on the accelerating structures for efficiency and beam stability. While numerical modeling has been quite standard in accelerator R&D, designing the NLC accelerating structure required a new simulation capability because of the geometric complexity and level of accuracy involved. Under the US DOE Advanced Computing initiatives (first the Grand Challenge and now SciDAC), SLAC has developed a suite of electromagnetic codes based on unstructured grids and utilizing high-performance computing to provide an advanced tool for modeling structures at accuracies and scales previously not possible. This paper will discuss the code development and computational science research (e.g. domain decomposition, scalable eigensolvers, adaptive mesh refinement) that have enabled the large-scale simulations needed for meeting the computational challenges posed by the NLC as well as projects such as the PEP-II and RIA. Numerical results will be presented to show how high-performance computing has made a qualitative improvement in accelerator structure modeling for these accelerators, either at the component level (single cell optimization), or on the scale of an entire structure (beam heating and long-range wakefields).

  12. High-Performance Computing in Accelerating Structure Design And Analysis

    SciTech Connect

    Li, Z.H.; Folwell, N.; Ge, Li-Xin; Guetz, A.; Ivanov, V.; Kowalski, M.; Lee, L.Q.; Ng, C.K.; Schussman, G.; Stingelin, L.; Uplenchwar, R.; Wolf, M.; Xiao, L.L.; Ko, K.; /SLAC /PSI, Villigen /Illinois U., Urbana

    2006-06-27

    Future high-energy accelerators such as the Next Linear Collider (NLC) will accelerate multi-bunch beams of high current and low emittance to obtain high luminosity, which put stringent requirements on the accelerating structures for efficiency and beam stability. While numerical modeling has been quite standard in accelerator R&D, designing the NLC accelerating structure required a new simulation capability because of the geometric complexity and level of accuracy involved. Under the US DOE Advanced Computing initiatives (first the Grand Challenge and now SciDAC), SLAC has developed a suite of electromagnetic codes based on unstructured grids and utilizing high performance computing to provide an advanced tool for modeling structures at accuracies and scales previously not possible. This paper will discuss the code development and computational science research (e.g. domain decomposition, scalable eigensolvers, adaptive mesh refinement) that have enabled the large-scale simulations needed for meeting the computational challenges posed by the NLC as well as projects such as the PEP-II and RIA. Numerical results will be presented to show how high performance computing has made a qualitative improvement in accelerator structure modeling for these accelerators, either at the component level (single cell optimization), or on the scale of an entire structure (beam heating and long range wakefields).

  13. 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.

  14. Comparison of high group velocity accelerating structures

    SciTech Connect

    Farkas, Z.D.; Wilson, P.B.

    1987-02-01

    It is well known that waveguides with no perturbations have phase velocities greater than the velocity of light c. If the waveguide dimensions are chosen so that the phase velocity is only moderately greater than c, only small perturbations are required to reduce the phase velocity to be synchronous with a high energy particle bunch. Such a lightly loaded accelerator structure will have smaller longitudinal and transverse wake potentials and hence will lead to lower emittance growth in an accelerated beam. Since these structures are lightly loaded, their group velocities are only slightly less than c and not in the order of 0.01c, as is the case for the standard disk-loaded structures. To ascertain that the peak and average power requirements for these structures are not prohibitive, we examine the elastance and the Q for several traveling wave structures: phase slip structures, bellows-like structures, and lightly loaded disk-loaded structures.

  15. Variable energy constant current accelerator structure

    DOEpatents

    Anderson, Oscar A.

    1990-01-01

    A variable energy, constant current ion beam accelerator structure is disclosed comprising an ion source capable of providing the desired ions, a pre-accelerator for establishing an initial energy level, a matching/pumping module having means for focusing means for maintaining the beam current, and at least one main accelerator module for continuing beam focus, with means capable of variably imparting acceleration to the beam so that a constant beam output current is maintained independent of the variable output energy. In a preferred embodiment, quadrupole electrodes are provided in both the matching/pumping module and the one or more accelerator modules, and are formed using four opposing cylinder electrodes which extend parallel to the beam axis and are spaced around the beam at 90.degree. intervals with opposing electrodes maintained at the same potential. Adjacent cylinder electrodes of the quadrupole structure are maintained at different potentials to thereby reshape the cross section of the charged particle beam to an ellipse in cross section at the mid point along each quadrupole electrode unit in the accelerator modules. The beam is maintained in focus by alternating the major axis of the ellipse along the x and y axis respectively at adjacent quadrupoles. In another embodiment, electrostatic ring electrodes may be utilized instead of the quadrupole electrodes.

  16. The grating as an accelerating structure

    SciTech Connect

    Fernow, R.C.

    1991-02-01

    This report considers the use of a diffraction grating as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of a grating. Calculations are made of the strength of the accelerating modes for structures with {pi} and 2{pi} phase advance per period and for incident waves polarized with either the E or H vector along the grooves of the grating. We consider examples of using gratings in a laser linac and in a grating lens. We also briefly examine previous results published about this subject. 36 refs.

  17. Summary report of working group 3: Laser and high-gradient structure-based acceleration

    NASA Astrophysics Data System (ADS)

    Andonian, Gerard; Simakov, Evgenya

    2017-03-01

    High-gradient particle acceleration with reduced power demands is essential for miniaturization and cost reduction of future accelerators. Applications for compact accelerators span collider research for High Energy Physics, light source development for Basic Energy Sciences and National Security, and industrial accelerators for Energy and Environmental Applications. Working Group 3 discussed and surveyed the recent advances in achieving higher gradients and better acceleration efficiency in externally powered, structure-based accelerators. The topics covered in Working Group 3 included dielectric laser acceleration, millimeter-wave accelerators, breakdown phenomena, exotic topologies such as photonic band-gap structures, artificial materials, and nanostructures, and novel rf technology.

  18. Development of beryllium-based neutron target system with three-layer structure for accelerator-based neutron source for boron neutron capture therapy.

    PubMed

    Kumada, Hiroaki; Kurihara, Toshikazu; Yoshioka, Masakazu; Kobayashi, Hitoshi; Matsumoto, Hiroshi; Sugano, Tomei; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

    2015-12-01

    The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future.

  19. Advanced Microgravity Acceleration Measurement Systems (AMAMS) Being Developed

    NASA Technical Reports Server (NTRS)

    Sicker, Ronald J.; Kacpura, Thomas J.

    2003-01-01

    The Advanced Microgravity Acceleration Measurement Systems (AMAMS) project is part of NASA s Instrument Technology Development program to develop advanced sensor systems. The primary focus of the AMAMS project is to develop microelectromechanical systems (MEMS) for acceleration sensor systems to replace existing electromechanical sensor systems presently used to assess relative gravity levels aboard spacecraft. These systems are used to characterize both vehicle and payload responses to low-gravity vibroacoustic environments. The collection of microgravity acceleration data is useful to the microgravity life sciences, microgravity physical sciences, and structural dynamics communities. The inherent advantages of semiconductor-based systems are reduced size, mass, and power consumption, with enhanced long-term calibration stability.

  20. Summary report of working group 3: High gradient and laser-structure based acceleration

    SciTech Connect

    Solyak, N.; Cowan, B.M.; /Tech-X, Boulder

    2010-01-01

    The charge for the working group on high gradient and laser-structure based acceleration was to assess the current challenges involved in developing an advanced accelerator based on electromagnetic structures, and survey state-of-the-art methods to address those challenges. The topics of more than 50 presentations in the working group covered a very broad range of issues, from ideas, theoretical models and simulations, to design and manufacturing of accelerating structures and, finally, experimental results on obtaining extremely high accelerating gradients in structures from conventional microwave frequency range up to THz and laser frequencies. Workshop discussion topics included advances in the understanding of the physics of breakdown and other phenomena, limiting high gradient performance of accelerating structures. New results presented in this workshop demonstrated significant progress in the fields of conventional vacuum structure-based acceleration, dielectric wakefield acceleration, and laser-structure acceleration.

  1. Induction accelerator development for heavy ion fusion

    SciTech Connect

    Reginato, L.L.

    1993-05-01

    For approximately a decade, the Heavy Ion Fusion Accelerator Research (HIFAR) group at LBL has been exploring the use of induction accelerators with multiple beams as the driver for inertial fusion targets. Scaled experiments have investigated the transport of space charge dominated beams (SBTE), and the current amplification and transverse emittance control in induction linacs (MBE-4) with very encouraging results. In order to study many of the beam manipulations required by a driver and to further develop economically competitive technology, a proposal has been made in partnership with LLNL to build a 10 MeV accelerator and to conduct a series of experiments collectively called the Induction Linac System Experiments (ILSE). The major components critical to the ILSE accelerator are currently under development. We have constructed a full scale induction module and we have tested a number of amorphous magnetic materials developed by Allied Signal to establish an overall optimal design. The electric and magnetic quadrupoles critical to the transport and focusing of heavy ion beams are also under development The hardware is intended to be economically competitive for a driver without sacrificing any of the physics or performance requirements. This paper will concentrate on the recent developments and tests of the major components required by the ILSE accelerator.

  2. Accelerating development of advanced inverters :

    SciTech Connect

    Neely, Jason C.; Gonzalez, Sigifredo; Ropp, Michael; Schutz, Dustin

    2013-11-01

    The high penetration of utility interconnected photovoltaic (PV) systems is causing heightened concern over the effect that variable renewable generation will have on the electrical power system (EPS). These concerns have initiated the need to amend the utility interconnection standard to allow advanced inverter control functionalities that provide: (1) reactive power control for voltage support, (2) real power control for frequency support and (3) better tolerance of grid disturbances. These capabilities are aimed at minimizing the negative impact distributed PV systems may have on EPS voltage and frequency. Unfortunately, these advanced control functions may interfere with island detection schemes, and further development of advanced inverter functions requires a study of the effect of advanced functions on the efficacy of antiislanding schemes employed in industry. This report summarizes the analytical, simulation and experimental work to study interactions between advanced inverter functions and anti-islanding schemes being employed in distributed PV systems.

  3. Accelerated Leadership Development: Fast Tracking School Leaders

    ERIC Educational Resources Information Center

    Earley, Peter; Jones, Jeff

    2010-01-01

    "Accelerated Leadership Development" captures and communicates the lessons learned from successful fast-track leadership programmes in the private and public sector, and provides a model which schools can follow and customize as they plan their own leadership development strategies. As large numbers of headteachers and other senior staff…

  4. Advanced accelerator and mm-wave structure research at LANL

    SciTech Connect

    Simakov, Evgenya Ivanovna

    2016-06-22

    This document outlines acceleration projects and mm-wave structure research performed at LANL. The motivation for PBG research is described first, with reference to couplers for superconducting accelerators and structures for room-temperature accelerators and W-band TWTs. These topics are then taken up in greater detail: PBG structures and the MIT PBG accelerator; SRF PBG cavities at LANL; X-band PBG cavities at LANL; and W-band PBG TWT at LANL. The presentation concludes by describing other advanced accelerator projects: beam shaping with an Emittance Exchanger, diamond field emitter array cathodes, and additive manufacturing of novel accelerator structures.

  5. High average power linear induction accelerator development

    SciTech Connect

    Bayless, J.R.; Adler, R.J.

    1987-07-01

    There is increasing interest in linear induction accelerators (LIAs) for applications including free electron lasers, high power microwave generators and other types of radiation sources. Lawrence Livermore National Laboratory has developed LIA technology in combination with magnetic pulse compression techniques to achieve very impressive performance levels. In this paper we will briefly discuss the LIA concept and describe our development program. Our goals are to improve the reliability and reduce the cost of LIA systems. An accelerator is presently under construction to demonstrate these improvements at an energy of 1.6 MeV in 2 kA, 65 ns beam pulses at an average beam power of approximately 30 kW. The unique features of this system are a low cost accelerator design and an SCR-switched, magnetically compressed, pulse power system. 4 refs., 7 figs.

  6. Progress on Diamond-Based Cylindrical Dielectric Accelerating Structures

    NASA Astrophysics Data System (ADS)

    Kanareykin, A.; Schoessow, P.; Conde, M.; Gai, W.

    2006-11-01

    The development of a high gradient diamond-based cylindrical dielectric loaded accelerator (DLA) is presented. A diamond-loaded DLA can potentially sustain accelerating gradients far in excess of the limits experimentally observed for conventional metallic accelerating structures. The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators: high rf breakdown level, extremely low dielectric losses and the highest available thermoconductive coefficient. We used the hot-filament Chemical Vapor Deposition (CVD) process to produce high quality 5-10 cm long cylindrical diamond layers. Our collaboration has also been developing a new method of CVD diamond surface preparation that reduces the secondary electron emission coefficient below unity. Special attention was paid to the numerical optimization of the waveguide to structure rf coupling section, where the surface magnetic and electric fields were minimized relative to the accelerating gradient and within known metal surface breakdown limits. We conclude with a brief overview of the use of diamond microstructures for use in compact rf sources.

  7. Vehicle Systems Integration Laboratory Accelerates Powertrain Development

    ScienceCinema

    None

    2016-07-12

    ORNL's Vehicle Systems Integration (VSI) Laboratory accelerates the pace of powertrain development by performing prototype research and characterization of advanced systems and hardware components. The VSI Lab is capable of accommodating a range of platforms from advanced light-duty vehicles to hybridized Class 8 powertrains with the goals of improving overall system efficiency and reducing emissions.

  8. Target and accelerator developments at CTI

    NASA Astrophysics Data System (ADS)

    Alvord, C. W.; Mendez, A. J.; Wittner, D. E.

    2001-07-01

    The accelerator products marketed by CTI have exclusively focused on proton-only, low energy (11 MeV) designs. This choice best suited the research customer, interested in producing several doses a day of a variety of positron emitting compounds. The PET cyclotron market has evolved into a high output, cost driven, competitive radiotracer production environment. A thoughtful analysis of the choices of energy and particle reveals that an 11 MeV proton accelerator outfitted with target changers and automated target loading and unloading equipment is still the best choice for FDG distribution. However technological innovations are required to face the challenges of the rapidly growing PET radiotracer business. Modifications to the CTI line of accelerators developed to face this evolving need will be presented.

  9. Woodpile Structure Fabrication for Photonic Crystal Laser Acceleration

    SciTech Connect

    McGuinness, C.; Colby, E.; England, R. J.; Noble, R. J.; Sears, C. M.; Siemann, R.; Spencer, J.; Waltz, D.; Byer, R. L.; Plettner, T.; Cowan, B. M.

    2009-01-22

    We describe initial steps at fabricating a dielectric photonic bandgap accelerator structure designed to operate at near IR frequencies. Such a structure operating at these frequencies requires extremely small, sub-micron sized features, forcing one to use lithographic means for fabrication. A process based upon lithographic equipment at the Stanford Nanofabrication Facility has been developed and a four layer test structure has been fabricated. Unexpected problems with the final etch step, and corresponding modifications to the process flow addressing these problems, are described. Spectroscopic measurements of the structure have been taken and are compared to simulations.

  10. Woodpile Structure Fabrication for Photonic Crystal Laser Acceleration

    SciTech Connect

    McGuinness, C.; Byer, R.L.; Colby, E.; Cowan, B.M.; England, R.J.; Noble, R.J.; Plettner, T.; Sears, C.M.; Siemann, R.; Spencer, J.; Waltz, D.; /SLAC

    2010-06-30

    We describe initial steps at fabricating a dielectric photonic bandgap accelerator structure designed to operate at near IR frequencies. Such a structure operating at these frequencies requires extremely small, sub-micron sized features, forcing one to use lithographic means for fabrication. A process based upon lithographic equipment at the Stanford Nanofabrication Facility has been developed and a four layer test structure has been fabricated. Unexpected problems with the final etch step, and corresponding modifications to the process flow addressing these problems, are described. Spectroscopic measurements of the structure have been taken and are compared to simulations.

  11. Development of a Wireless Displacement Measurement System Using Acceleration Responses

    PubMed Central

    Park, Jong-Woong; Sim, Sung-Han; Jung, Hyung-Jo; Spencer, Billie F.

    2013-01-01

    Displacement measurements are useful information for various engineering applications such as structural health monitoring (SHM), earthquake engineering and system identification. Most existing displacement measurement methods are costly, labor-intensive, and have difficulties particularly when applying to full-scale civil structures because the methods require stationary reference points. Indirect estimation methods converting acceleration to displacement can be a good alternative as acceleration transducers are generally cost-effective, easy to install, and have low noise. However, the application of acceleration-based methods to full-scale civil structures such as long span bridges is challenging due to the need to install cables to connect the sensors to a base station. This article proposes a low-cost wireless displacement measurement system using acceleration. Developed with smart sensors that are low-cost, wireless, and capable of on-board computation, the wireless displacement measurement system has significant potential to impact many applications that need displacement information at multiple locations of a structure. The system implements an FIR-filter type displacement estimation algorithm that can remove low frequency drifts typically caused by numerical integration of discrete acceleration signals. To verify the accuracy and feasibility of the proposed system, laboratory tests are carried out using a shaking table and on a three storey shear building model, experimentally confirming the effectiveness of the proposed system. PMID:23881123

  12. Dielectric-Lined High-Gradient Accelerator Structure

    SciTech Connect

    Jay L. Hirshfield

    2012-04-24

    Rectangular particle accelerator structures with internal planar dielectric elements have been studied, with a view towards devising structures with lower surface fields for a given accelerating field, as compared with structures without dielectrics. Success with this concept is expected to allow operation at higher accelerating gradients than otherwise on account of reduced breakdown probabilities. The project involves studies of RF breakdown on amorphous dielectrics in test cavities that could enable high-gradient structures to be built for a future multi-TeV collider. The aim is to determine what the limits are for RF fields at the surfaces of selected dielectrics, and the resulting acceleration gradient that could be achieved in a working structure. The dielectric of principal interest in this study is artificial CVD diamond, on account of its advertised high breakdown field ({approx}2 GV/m for dc), low loss tangent, and high thermal conductivity. Experimental studies at mm-wavelengths on materials and structures for achieving high acceleration gradient were based on the availability of the 34.3 GHz third-harmonic magnicon amplifier developed by Omega-P, and installed at the Yale University Beam Physics Laboratory. Peak power from the magnicon was measured to be about 20 MW in 0.5 {micro}s pulses, with a gain of 54 dB. Experiments for studying RF high-field effects on CVD diamond samples failed to show any evidence after more than 10{sup 5} RF pulses of RF breakdown up to a tangential surface field strength of 153 MV/m; studies at higher fields were not possible due to a degradation in magnicon performance. A rebuild of the tube is underway at this writing. Computed performance for a dielectric-loaded rectangular accelerator structure (DLA) shows highly competitive properties, as compared with an existing all-metal structure. For example, comparisons were made of a DLA structure having two planar CVD diamond elements with a all-metal CERN structure HDS

  13. Accelerated vaccine development against emerging infectious diseases.

    PubMed

    Leblanc, Pierre R; Yuan, Jianping; Brauns, Tim; Gelfand, Jeffrey A; Poznansky, Mark C

    2012-07-01

    Emerging and re-emerging infectious diseases represent a major challenge to vaccine development since it involves two seemingly contradictory requirements. Rapid and flexible vaccine generation while using technologies and processes that can facilitate accelerated regulatory review. Development in the "-omics" in combination with advances in vaccinology offer novel opportunities to meet these requirements. Here we describe how a consortium of five different organizations from academia and industry is addressing these challenges. This novel approach has the potential to become the new standard in vaccine development allowing timely deployment to avert potential pandemics.

  14. Developing acceleration schedules for NDCX-II

    SciTech Connect

    Sharp, W.M.; Friedman, A.; Grote, D.P.; Henestroza, E.; Leitner, M.A.; Waldron, W.L.

    2008-08-01

    The Virtual National Laboratory for Heavy-Ion Fusion Science is developing a physics design for NDCX-II, an experiment to study warm dense matter heated by ions near the Bragg-peak energy. Present plans call for using about thirty induction cells to accelerate 30 nC of Li+ ions to more than 3 MeV, followed by neutralized drift-compression. To heat targets to useful temperatures, the beam must be compressed to a millimeter-scale radius and a duration of about 1 ns. An interactive 1-D particle-in-cell simulation with an electrostatic field solver, acceleration-gap fringe fields, and a library of realizable analytic waveforms has been used for developing NDCX-II acceleration schedules. Axisymmetric simulations with WARP have validated this 1-D model and have been used both to design transverse focusing and to compensate for injection non-uniformities and radial variation of the fields. Highlights of this work are presented here.

  15. Locating Bound Structures in the Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Pearson, David; Batuski, D. J.

    2013-01-01

    Given the overwhelming evidence of the universe’s accelerating expansion, the question of what structures are gravitationally bound becomes one of utmost interest. Dunner et al. 2006 (D06) and Busha et al. 2003 (B03) set out to answer this question analytically, and they arrived at fairly different answers owing to the differences in their assumptions of velocities at the present epoch. Applying their criteria to different superclusters, it’s possible to make predictions about what structures may be bound. We apply the criteria of D06 and B03 to the Aquarius, Microscopium, Corona Borealis, and Shapley superclusters to make predictions about what structures might be bound and compare with the results of simple N-body simulations to determine which method is a better predictor and to determine the likelihood that parts or all of the superclusters listed above are bound. We find that D06 tend to predict more structure to be bound than B03, and the results of the N-body simulations usually lie somewhere in between the two sets of predictions. Observational evidence, and simulation data suggests that pairs of clusters in Aquarius and Microscopium are gravitationally bound, and that Shapley contains a large complex of clusters that are bound, along with some additional bound pairs. The likelihood that any of the clusters in Corona Borealis are bound to one another is very small, contrary to the claims of Small et al. 1998, who claimed that the entire supercluster is likely gravitationally bound. Busha M. T., Adams F. C., Wechsler R. H., Evrard A. E., 2003, ApJ, 596, 713 Dunner R., Araya P. A., Meza A., Reisenegger A., 2006, MNRAS, 306, 803 Small T. A., Ma C., Sargent W. L. W., Hamilton D., 1998, ApJ, 492, 45

  16. Guidelines for Developing an Academic Acceleration Policy

    ERIC Educational Resources Information Center

    Colangelo, Nicholas; Assouline, Susan G.; Marron, Maureen A.; Castellano, Jaime A.; Clinkenbeard, Pamela R.; Rogers, Karen; Calvert, Eric; Malek, Rosanne; Smith, Donnajo

    2010-01-01

    As an educational intervention, acceleration is decidedly effective for high-ability students. The research support for acceleration that has accumulated over many decades is robust and consistent and allows us to confidently state that carefully planned acceleration decisions are successful. Both grade-based and content-based acceleration are…

  17. Development of a fast voltage control method for electrostatic accelerators

    NASA Astrophysics Data System (ADS)

    Lobanov, Nikolai R.; Linardakis, Peter; Tsifakis, Dimitrios

    2014-12-01

    The concept of a novel fast voltage control loop for tandem electrostatic accelerators is described. This control loop utilises high-frequency components of the ion beam current intercepted by the image slits to generate a correction voltage that is applied to the first few gaps of the low- and high-energy acceleration tubes adjoining the high voltage terminal. New techniques for the direct measurement of the transfer function of an ultra-high impedance structure, such as an electrostatic accelerator, have been developed. For the first time, the transfer function for the fast feedback loop has been measured directly. Slow voltage variations are stabilised with common corona control loop and the relationship between transfer functions for the slow and new fast control loops required for optimum operation is discussed. The main source of terminal voltage instabilities, which are due to variation of the charging current caused by mechanical oscillations of charging chains, has been analysed.

  18. High-performance insulator structures for accelerator applications

    SciTech Connect

    Sampayan, S.E.; Caporaso, G.J.; Sanders, D.M.; Stoddard, R.D.; Trimble, D.O.; Elizondo, J.; Krogh, M.L.; Wieskamp, T.F.

    1997-05-01

    A new, high gradient insulator technology has been developed for accelerator systems. The concept involves the use of alternating layers of conductors and insulators with periods of order 1 mm or less. These structures perform many times better (about 1.5 to 4 times higher breakdown electric field) than conventional insulators in long pulse, short pulse, and alternating polarity applications. We describe our ongoing studies investigating the degradation of the breakdown electric field resulting from alternate fabrication techniques, the effect of gas pressure, the effect of the insulator-to-electrode interface gap spacing, and the performance of the insulator structure under bi-polar stress.

  19. Vanguard industrial linear accelerator rapid product development

    NASA Astrophysics Data System (ADS)

    Harroun, Jim

    1994-07-01

    Siemens' ability to take the VanguardTM Industrial Linear Accelerator from the development stage to the market place in less than two years is described. Emphasis is on the development process, from the business plan through the shipment of the first commercial sale. Included are discussions on the evolution of the marketing specifications, with emphasis on imaging system requirements, as well as flexibility for expansion into other markets. Requirements used to create the engineering specifications, how they were incorporated into the design, and lessons learned from the demonstration system are covered. Some real-life examples of unanticipated problems are presented, as well as how they were resolved, including some discussion of the special problems encountered in developing a user interface and a training program for an international customer.

  20. Operational experience with room temperature continuous wave accelerator structures

    NASA Astrophysics Data System (ADS)

    Alimov, A. S.; Ishkhanov, B. S.; Piskarev, I. M.; Shvedunov, V. I.; Tiunov, A. V.

    1993-05-01

    The paper reports the results of the computer simulation of parameters of the on-axis coupled accelerator structure for the continuous wave racetrack microtron. The operational experience with the accelerating sections on the basis of the on-axis coupled structure is described.

  1. R&D of Accelerator Structures at SLAC

    SciTech Connect

    Wang, J.W.; /SLAC

    2007-01-17

    The research activities for accelerator structures at SLAC are reviewed including the achievement via the main linac design for the Next Linear Collider (NLC), the program adjustment after the decision of the International Linear Collider (ILC) to be based on superconducting technology, and the work progress for the ILC, photon science at SLAC and basic accelerator structure studies.

  2. Manifold damping of the NLC detuned accelerating structure

    NASA Astrophysics Data System (ADS)

    Kroll, N.; Thompson, K.; Bane, K.; Gluckstern, R.; Ko, K.; Miller, R.; Ruth, R.

    1995-06-01

    In order to mitigate the reappearance of the HOM wakefield of a detuned accelerator structure and relax tolerance requirements, we propose to provide low level damping by coupling all cavities to several identical and symmetrically located waveguides (manifolds) which run parallel to each accelerator structure and are terminated at each end by matched loads. The waveguides are designed such that all modes which couple to the acceleration mode are non-propagating at the acceleration mode frequency. Hence the coupling irises can be designed to provide large coupling to higher frequency modes without damping the acceleration mode. Because the higher order modes are detuned, they are localized and have a broad spectrum of phase velocities of both signs. They are therefore capable of coupling effectively to all propagating modes in the waveguides. Methods of analyzing and results obtained for the very complex system of modes in the accelerating structure and manifolds are presented.

  3. Manifold damping of the NLC detuned accelerating structure

    SciTech Connect

    Kroll, N.; Thompson, K.; Bane, K.; Ko, K.; Miller, R.; Ruth, R.; Gluckstern, R.

    1994-09-01

    In order to investigate the reappearance of the HOM wakefield of a detuned accelerator structure and relax tolerance requirements, we propose to provide low level damping by coupling all cavities to several identical and symmetrically located waveguides (manifolds) which run parallel to each accelerator structure and are terminated at each end by matched loads. The waveguides are designed such that all modes which couple to the acceleration mode are non-propagating at the acceleration mode frequency. Hence the coupling irises can be designed to provide large coupling to higher frequency modes without damping the acceleration mode. Because the higher order modes are detuned, they are localized and have a broad spectrum of phase velocities of both signs. They are therefore capable of coupling effectively to all propagating modes in the waveguides. Methods of analyzing and results obtained for the very complex system of modes in the accelerating structure and manifolds are presented.

  4. Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin; Lin, M.C.; Schwartz, Brian; Byer, Robert; McGuinness, Christopher; Colby, Eric; England, Robert; Noble, Robert; Spencer, James; /SLAC

    2012-07-02

    Photonic crystal waveguides are promising candidates for laser-driven accelerator structures because of their ability to confine a speed-of-light mode in an all-dielectric structure. Because of the difference between the group velocity of the waveguide mode and the particle bunch velocity, fields must be coupled into the accelerating waveguide at frequent intervals. Therefore efficient, compact couplers are critical to overall accelerator efficiency. We present designs and simulations of high-efficiency coupling to the accelerating mode in a three-dimensional photonic crystal waveguide from a waveguide adjoining it at 90{sup o}. We discuss details of the computation and the resulting transmission. We include some background on the accelerator structure and photonic crystal-based optical acceleration in general.

  5. Developments in accelerators for heavy ion fusion

    SciTech Connect

    Keefe, D.

    1985-05-01

    The long term goal of Heavy Ion Fusion (HIF) is the development of an accelerator with the large beam power, large beam stored-energy, and high brightness needed to implode small deuterium-tritium capsules for fusion power. While studies of an rf linac/storage ring combination as an inertial fusion driver continue in Japan and Europe, the US program in recent times has concentrated on the study of the suitability of linear induction acceleration of ions for this purpose. Novel features required include use of multiple beams, beam current amplification in the linac, and manipulation of long beam bunches with a large velocity difference between head and tail. Recent experiments with an intense bright beam of cesium ions have established that much higher currents can be transported in a long quadrupole system than was believed possible a few years ago. A proof-of-principle ion induction linac to demonstrate beam current amplification with multiple beams is at present being fabricated at LBL. 28 refs., 4 figs.

  6. Particle accelerations and current structures of Weibel and Filamentation instabilities

    NASA Astrophysics Data System (ADS)

    Ryu, C. M.; Huynh, C. T.

    2015-12-01

    Particle accelerations of the Wibel instability (WI) and the Filamentation instability(FI) are studied by using PIC simuations, comparing them side-by-side. Although two instabilities are almost identical in the linear growth phase, significant differences are found in the nonlinear phase in their particle accelerations and current structures. The FI shows enhanced electron acceleration, whereas particle acceleration is almost absent in the WI. The different particle accelerations between the FI and the WI seem to be associated with their different current structures; a hollow electron current structure for the FI and a center filled current structure for that of the WI. Different electron distributions seem to bring in different current filament structures, eventually leading to different magnetic characteristics.

  7. Design of Accelerator Online Simulator Server Using Structured Data

    SciTech Connect

    Shen, Guobao; Chu, Chungming; Wu, Juhao; Kraimer, Martin; /Argonne

    2012-07-06

    Model based control plays an important role for a modern accelerator during beam commissioning, beam study, and even daily operation. With a realistic model, beam behaviour can be predicted and therefore effectively controlled. The approach used by most current high level application environments is to use a built-in simulation engine and feed a realistic model into that simulation engine. Instead of this traditional monolithic structure, a new approach using a client-server architecture is under development. An on-line simulator server is accessed via network accessible structured data. With this approach, a user can easily access multiple simulation codes. This paper describes the design, implementation, and current status of PVData, which defines the structured data, and PVAccess, which provides network access to the structured data.

  8. Fabrication of x-band accelerating structures at Fermilab

    SciTech Connect

    Tug T Arkan et al.

    2004-07-20

    The RF Technology Development group at Fermilab is working together with the NLC and GLC groups at SLAC and KEK on developing technology for room temperature X-band accelerating structures for a future linear collider. We built six 60-cm long, high phase advance, detuned structures (HDS or FXB series). These structures have 150 degrees phase advance per cell, and are intended for high gradient tests. The structures were brazed in a vacuum furnace with a partial pressure of argon, rather than in a hydrogen atmosphere. We have also begun to build 60-cm long, damped and detuned structures (HDDS or FXC/FXD series). We have built 5 FXC and 1 FXD structures. Our goal was to build six structures for the 8-pack test at SLAC by the end of March 2004, as part of the GLC/NLC effort to demonstrate the readiness of room temperature RF technology for a linear collider. This paper describes the RF structure factory infrastructure (clean rooms, vacuum furnaces, vacuum equipment, RF equipment etc.), and the fabrication techniques utilized (the machining of copper cells/couplers, quality control, etching, vacuum brazing, cleanliness requirements etc.) for the production of FXB and FXC/FXD structures.

  9. Neutron Diagnostic Development for the Z Accelerator

    NASA Astrophysics Data System (ADS)

    Hahn, Kelly; Chandler, G. A.; Ruiz, C. L.; Jones, B.; Gomez, M. R.; Knapp, P. F.; Sefkow, A. B.; Hansen, S. B.; Schmit, P. F.; Harding, E. C.; Norris, E.; Torres, J. A.; Cooper, G. W.; Styron, J. D.; Frenje, J.; Lahmann, B.; Gatu-Johnson, M.; Seguin, F.; Petrasso, R.; Fittinghoff, D.; May, M.; Snyder, L.; Moy, K.; Buckles, R.; Glebov, V. Yu.

    2016-10-01

    We are studying Magnetized Liner Inertial Fusion (MagLIF) and Gas Puff fusion neutron sources on the Z accelerator. MagLIF experiments have produced up to 3e12 primary DD neutrons with 2-3 keV ion temperatures and 1-2 ns burn widths. Gas puff experiments have produced up to 5e13 primary DD neutrons with higher ion temperatures, longer burn times, and evidence of non-thermonuclear production. For MagLIF, the yield is expected to increase rapidly with increased energy coupling, yet it remains unclear if Gas Puffs would scale as attractively. We review neutron measurements for these experiments and plans for developing neutron diagnostics for these two very different sources. Sandia is sponsored by the U.S. DOE's NNSA under contract DE-AC04-94AL85000.

  10. Investigations of the plasma and structure based accelerators

    SciTech Connect

    Shvets, Gennady

    2012-08-30

    The objective of our research during the reported period was three-fold: (a) theoretical investigation of novel mechanisms of injection into laser wake field accelerators; (b) theoretical investigation of single-shot frequency domain diagnostics of relativistic plasma wakes, specifically in the context of spatio-temporal evolution of the plasma bubble;(c) experimental and theoretical investigation of laser-driven accelerating structure, specifically in the context of the Surface Wave Accelerator Based on SiC (SWABSIC).

  11. Helical Pulse Line Structures for Ion Acceleration

    SciTech Connect

    Briggs, R.J.; Reginato, L.L.; Waldron, W.L.

    2005-05-01

    The basic concept of the ''Pulse Line Ion Accelerator'' is presented, where pulse power sources create a ramped traveling wave voltage pulse on a helical pulse line. Ions can surf on this traveling wave and achieve energy gains much larger than the peak applied voltage. Tapered and untapered lines are compared, and a transformer coupling technique for launching the wave is described.

  12. Accelerating Adverse Outcome Pathway (AOP) development ...

    EPA Pesticide Factsheets

    The Adverse Outcome Pathway (AOP) framework is increasingly being adopted as a tool for organizing and summarizing the mechanistic information connecting molecular perturbations by environmental stressors with adverse outcomes relevant for ecological and human health outcomes. However, the conventional process for assembly of these AOPs is time and resource intensive, and has been a rate limiting step for AOP use and development. Therefore computational approaches to accelerate the process need to be developed. We previously developed a method for generating computationally predicted AOPs (cpAOPs) by association mining and integration of data from publicly available databases. In this work, a cpAOP network of ~21,000 associations was established between 105 phenotypes from TG-GATEs rat liver data from different time points (including microarray, pathological effects and clinical chemistry data), 994 REACTOME pathways, 688 High-throughput assays from ToxCast and 194 chemicals. A second network of 128,536 associations was generated by connecting 255 biological target genes from ToxCast to 4,980 diseases from CTD using either HT screening activity from ToxCast for 286 chemicals or CTD gene expression changes in response to 2,330 chemicals. Both networks were separately evaluated through manual extraction of disease-specific cpAOPs and comparison with expert curation of the relevant literature. By employing data integration strategies that involve the weighting of n

  13. Experimental demonstration of Wakefield acceleration in a tunable dielectric loaded accelerating structure.

    SciTech Connect

    Liu, W.; Power, J. G.; Conde, M.; Antipov, S.; Schoessow, P.; Gai, W.; Jing, C.; Kanareykin, A.; Schoessow, P.

    2011-04-21

    We report on a collinear wakefield experiment using the first tunable dielectric loaded accelerating structure. By introducing an extra layer of nonlinear ferroelectric, which has a dielectric constant sensitive to temperature and dc bias, the frequency of a dielectric loaded accelerating structure can be tuned. During the experiment, the energy of a witness bunch at a fixed delay with respect to the drive beam was measured while the temperature of the structure was scanned over a 50 C range. The energy change corresponded to a change of more than half of the nominal structure wavelength.

  14. Experimental Demonstration of Wakefield Acceleration in a Tunable Dielectric Loaded Accelerating Structure

    SciTech Connect

    Jing, C.; Antipov, S.; Kanareykin, A.; Schoessow, P.; Power, J. G.; Conde, M.; Liu, W.; Gai, W.

    2011-04-22

    We report on a collinear wakefield experiment using the first tunable dielectric loaded accelerating structure. By introducing an extra layer of nonlinear ferroelectric, which has a dielectric constant sensitive to temperature and dc bias, the frequency of a dielectric loaded accelerating structure can be tuned. During the experiment, the energy of a witness bunch at a fixed delay with respect to the drive beam was measured while the temperature of the structure was scanned over a 50 deg. C range. The energy change corresponded to a change of more than half of the nominal structure wavelength.

  15. ELECTROMAGNETIC SIMULATIONS OF DIELECTRIC WALL ACCELERATOR STRUCTURES FOR ELECTRON BEAM ACCELERATION

    SciTech Connect

    Nelson, S D; Poole, B R

    2005-05-05

    Dielectric Wall Accelerator (DWA) technology incorporates the energy storage mechanism, the switching mechanism, and the acceleration mechanism for electron beams. Electromagnetic simulations of DWA structures includes these effects and also details of the switch configuration and how that switch time affects the electric field pulse which accelerates the particle beam. DWA structures include both bi-linear and bi-spiral configurations with field gradients on the order of 20MV/m and the simulations include the effects of the beampipe, the beampipe walls, the DWA High Gradient Insulator (HGI) insulating stack, wakefield impedance calculations, and test particle trajectories with low emittance gain. Design trade-offs include the transmission line impedance (typically a few ohms), equilibration ring optimization, driving switch inductances, and layer-to-layer coupling effects and the associated affect on the acceleration pulse's peak value.

  16. Accelerated Application Development: The ORNL Titan Experience

    DOE PAGES

    Joubert, Wayne; Archibald, Richard K.; Berrill, Mark A.; ...

    2015-05-09

    The use of computational accelerators such as NVIDIA GPUs and Intel Xeon Phi processors is now widespread in the high performance computing community, with many applications delivering impressive performance gains. However, programming these systems for high performance, performance portability and software maintainability has been a challenge. In this paper we discuss experiences porting applications to the Titan system. Titan, which began planning in 2009 and was deployed for general use in 2013, was the first multi-petaflop system based on accelerator hardware. To ready applications for accelerated computing, a preparedness effort was undertaken prior to delivery of Titan. In this papermore » we report experiences and lessons learned from this process and describe how users are currently making use of computational accelerators on Titan.« less

  17. Accelerated Application Development: The ORNL Titan Experience

    SciTech Connect

    Joubert, Wayne; Archibald, Richard K.; Berrill, Mark A.; Brown, W. Michael; Eisenbach, Markus; Grout, Ray; Larkin, Jeff; Levesque, John; Messer, Bronson; Norman, Matthew R.; Philip, Bobby; Sankaran, Ramanan; Tharrington, Arnold N.; Turner, John A.

    2015-05-09

    The use of computational accelerators such as NVIDIA GPUs and Intel Xeon Phi processors is now widespread in the high performance computing community, with many applications delivering impressive performance gains. However, programming these systems for high performance, performance portability and software maintainability has been a challenge. In this paper we discuss experiences porting applications to the Titan system. Titan, which began planning in 2009 and was deployed for general use in 2013, was the first multi-petaflop system based on accelerator hardware. To ready applications for accelerated computing, a preparedness effort was undertaken prior to delivery of Titan. In this paper we report experiences and lessons learned from this process and describe how users are currently making use of computational accelerators on Titan.

  18. Simulation Studies of the Dielectric Grating as an Accelerating and Focusing Structure

    SciTech Connect

    Soong, Ken; Peralta, E.A.; Byer, R.L.; Colby, E.; /SLAC

    2011-08-12

    A grating-based design is a promising candidate for a laser-driven dielectric accelerator. Through simulations, we show the merits of a readily fabricated grating structure as an accelerating component. Additionally, we show that with a small design perturbation, the accelerating component can be converted into a focusing structure. The understanding of these two components is critical in the successful development of any complete accelerator. The concept of accelerating electrons with the tremendous electric fields found in lasers has been proposed for decades. However, until recently the realization of such an accelerator was not technologically feasible. Recent advances in the semiconductor industry, as well as advances in laser technology, have now made laser-driven dielectric accelerators imminent. The grating-based accelerator is one proposed design for a dielectric laser-driven accelerator. This design, which was introduced by Plettner, consists of a pair of opposing transparent binary gratings, illustrated in Fig. 1. The teeth of the gratings serve as a phase mask, ensuring a phase synchronicity between the electromagnetic field and the moving particles. The current grating accelerator design has the drive laser incident perpendicular to the substrate, which poses a laser-structure alignment complication. The next iteration of grating structure fabrication seeks to monolithically create an array of grating structures by etching the grating's vacuum channel into a fused silica wafer. With this method it is possible to have the drive laser confined to the plane of the wafer, thus ensuring alignment of the laser-and-structure, the two grating halves, and subsequent accelerator components. There has been previous work using 2-dimensional finite difference time domain (2D-FDTD) calculations to evaluate the performance of the grating accelerator structure. However, this work approximates the grating as an infinite structure and does not accurately model a

  19. Accelerator mass spectrometry at the Australian National University's 14UD accelerator: experience and developments

    NASA Astrophysics Data System (ADS)

    Fifield, L. K.; Ophel, T. R.; Allan, G. L.; Bird, J. R.; Davie, R. F.

    1990-12-01

    Although the major emphasis of the joint ANU/ANSTO accelerator mass spectrometry program has been the measurement of 36Cl samples, both 14C and 10Be capabilities have been implemented recently on the 14UD accelerator. The new developments and operating experience are reviewed.

  20. Blind protein structure prediction using accelerated free-energy simulations

    PubMed Central

    Perez, Alberto; Morrone, Joseph A.; Brini, Emiliano; MacCallum, Justin L.; Dill, Ken A.

    2016-01-01

    We report a key proof of principle of a new acceleration method [Modeling Employing Limited Data (MELD)] for predicting protein structures by molecular dynamics simulation. It shows that such Boltzmann-satisfying techniques are now sufficiently fast and accurate to predict native protein structures in a limited test within the Critical Assessment of Structure Prediction (CASP) community-wide blind competition. PMID:27847872

  1. Theory of factors limiting high gradient operation of warm accelerating structures

    SciTech Connect

    Nusinovich, Gregory S.

    2014-07-22

    This report consists of two parts. In the first part we describe a study of the heating of microprotrusions on surfaces of accelerating structures. This ;process is believed to lead to breakdown in these structures. Our study revealed that for current accelerator parameters melting should not occur due to space charge limitations of the current emitted by a protrusion. The second part describes a novel concept to develop THz range sources based on harmonic cyclotron masers for driving future colliders. This work was stimulated by a recent request of SLAC to develop high power, high-efficiency sources of sub-THz radiation for future high-gradient accelerators.

  2. Technology development for high power induction accelerators

    SciTech Connect

    Birx, D.L.; Reginato, L.L.

    1985-06-11

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability.

  3. The structural response of a rail acceleration

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.

    1984-01-01

    The transient response of a 0.4 by 0.6 cm rectangular bore rail accelerator was analyzed by a three dimensional finite element code. The copper rail deflected to a peak value of 0.08 mm in compression and then oscillated at an amplitude of 0.02 mm. Simultaneously the insulating side wall of glass fabric base, epoxy resin laminate (G-10) was compressed to a peak value of 0.13 mm and rebounded to a steady state in extension. Projectile pinch or blowby due to the rail extension or compression, respectively, can be identified by examining the time history of the rail displacement. The effect of blowby was most significant at the side wall characterized by mm size displacement in compression. Dynamic stress calculations indicate that the G-10 supporting material behind the rail is subjected to over 21 MPa at which the G-10 could fail if the laminate was not carefully oriented. Results for a polycarbonate resin (Lexan) side wall show much larger displacements and stresses than for G-10. The tradeoff between the transparency of Lexan and the mechanical strength of G-10 for sidewall material is obvious. Displacement calculations from the modal method are smaller than the results from the direct integration method by almost an order of magnitude, because the high frequency effect is neglected. Previously announced in STAR as N83-35412

  4. The structural response of a rail accelerator

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.

    1983-01-01

    The transient response of a 0.4 by 0.6 cm rectangular bore rail accelerator was analyzed by a three dimensional finite element code. The copper rail deflected to a peak value of 0.08 mm in compression and then oscillated at an amplitude of 0.02 mm. Simultaneously the insulating side wall of glass fabric base, epoxy resin laminate (G-1o) was compressed to a peak value of 0.13 mm and rebounded to a steady state in extension. Projectile pinch or blowby due to the rail extension or compression, respectively, can be identified by examining the time history of the rail displacement. The effect of blowby was most significant at the side wall characterized by mm size displacement in compression. Dynamic stress calculations indicate that the G-10 supporting material behind the rail is subjected to over 21 MPa at which the G-10 could fail if the laminate was not carefully oriented. Results for a polycarbonate resin (Lexan) side wall show much larger displacements and stresses than for G-10. The tradeoff between the transparency of Lexan and the mechanical strength of G-10 for sidewall material is obvious. Displacement calculations from the modal method are smaller than the results from the direct integration method by almost an order of magnitude, because the high frequency effect is neglected.

  5. Feedback in Flow for Accelerated Reaction Development.

    PubMed

    Reizman, Brandon J; Jensen, Klavs F

    2016-09-20

    The pharmaceutical industry is investing in continuous flow and high-throughput experimentation as tools for rapid process development accelerated scale-up. Coupled with automation, these technologies offer the potential for comprehensive reaction characterization and optimization, but with the cost of conducting exhaustive multifactor screens. Automated feedback in flow offers researchers an alternative strategy for efficient characterization of reactions based on the use of continuous technology to control chemical reaction conditions and optimize in lieu of screening. Optimization with feedback allows experiments to be conducted where the most information can be gained from the chemistry, enabling product yields to be maximized and kinetic models to be generated while the total number of experiments is minimized. This Account opens by reviewing select examples of feedback optimization in flow and applications to chemical research. Systems in the literature are classified into (i) deterministic "black box" optimization systems that do not model the reaction system and are therefore limited in the utility of results for scale-up, (ii) deterministic model-based optimization systems from which reaction kinetics and/or mechanisms can be automatically evaluated, and (iii) stochastic systems. Though diverse in application, flow feedback systems have predominantly focused upon the optimization of continuous variables, i.e., variables such as time, temperature, and concentration that can be ramped from one experiment to the next. Unfortunately, this implies that the screening of discrete variables such as catalyst, ligand, or solvent generally does not factor into automated flow optimization, resulting in incomplete process knowledge. Herein, we present a system and strategy developed for optimizing discrete and continuous variables of a chemical reaction simultaneously. The approach couples automated feedback with high-throughput reaction screening in droplet flow

  6. Rectangular Dielectric-loaded Structures for Achieving High Acceleration Gradients

    NASA Astrophysics Data System (ADS)

    Wang, Changbiao; Yakovlev, V. P.; Marshall, T. C.; LaPointe, M. A.; Hirshfield, J. L.

    2006-11-01

    Rectangular dielectric-loaded structures are described that may sustain higher acceleration gradients than conventional all-metal structures with similar apertures. One structure is a test cavity designed to ascertain the breakdown limits of dielectrics, while a second structure could be the basis for a two-beam accelerator. CVD diamond is an attractive dielectric for a high-gradient structure, since the published DC breakdown limit for CVD diamond is ˜ 2 GV/m, although the limit has never been determined for RF fields. Here we present a design of a diamond-lined test cavity to measure the breakdown limit. The designed cavity operates at 34 GHz, where with 10-MW input power it is expected to produce an ˜800 MV/m field on the diamond surface—provided breakdown is avoided. The two channel rectangular dielectric-loaded waveguide could be a two-beam accelerator structure, in which a drive beam is in one channel and an accelerated beam is in the other. The RF power produced by drive bunches in the drive channel is continuously coupled to the acceleration channel. The ratio of fields in the channels (transformer ratio) for the operating mode can be designed by adjusting the dimensions of the structure. An example of the two-channel structure is described, in which a train of five 3-nC drive bunches excites wake fields in the accelerator channel of up to 1.3 GV/m with a transformer ratio of 10 for the design mode.

  7. rf breakdown tests of mm-wave metallic accelerating structures

    NASA Astrophysics Data System (ADS)

    Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; Clarke, Christine; Hogan, Mark; McCormick, Doug; Novokhatski, Alexander; Spataro, Bruno; Weathersby, Stephen; Tantawi, Sami G.

    2016-01-01

    We are exploring the physics and frequency-scaling of vacuum rf breakdowns at sub-THz frequencies. We present the experimental results of rf tests performed in metallic mm-wave accelerating structures. These experiments were carried out at the facility for advanced accelerator experimental tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. We compared the performances of metal structures made with copper and stainless steel. The rf frequency of the fundamental accelerating mode, propagating in the structures at the speed of light, varies from 115 to 140 GHz. The traveling wave structures are 0.1 m long and composed of 125 coupled cavities each. We determined the peak electric field and pulse length where the structures were not damaged by rf breakdowns. We calculated the electric and magnetic field correlated with the rf breakdowns using the FACET bunch parameters. The wakefields were calculated by a frequency domain method using periodic eigensolutions. Such a method takes into account wall losses and is applicable to a large variety of geometries. The maximum achieved accelerating gradient is 0.3 GV /m with a peak surface electric field of 1.5 GV /m and a pulse length of about 2.4 ns.

  8. Gradient Limitations in Room Temperature and Superconducting Acceleration Structures

    SciTech Connect

    Solyak, N. A.

    2009-01-22

    Accelerating gradient is a key parameter of the accelerating structure in large linac facilities, like future Linear Collider. In room temperature accelerating structures the gradient is limited mostly by breakdown phenomena, caused by high surface electric fields or pulse surface heating. High power processing is a necessary procedure to clean surface and improve the gradient. In the best tested X-band structures the achieved gradient is exceed 100 MV/m in of {approx}200 ns pulses for breakdown rate of {approx}10{sup -7}. Gradient limit depends on number of factors and no one theory which can explain all sets of experimental results and predict gradient in new accelerating structure. In paper we briefly overview the recent experimental results of breakdown studies, progress in understanding of gradient limitations and scaling laws. Although superconducting rf technology has been adopted throughout the world for ILC, it has frequently been difficult to reach the predicted performance in these structures due to a number of factors: multipactoring, field emission, Q-slope, thermal breakdown. In paper we are discussing all these phenomena and the ways to increase accelerating gradient in SC cavity, which are a part of worldwide R and D program.

  9. Gradient limitations in room temperature and superconducting acceleration structures

    SciTech Connect

    Solyak, N.A.; /Fermilab

    2008-10-01

    Accelerating gradient is a key parameter of the accelerating structure in large linac facilities, like future Linear Collider. In room temperature accelerating structures the gradient is limited mostly by breakdown phenomena, caused by high surface electric fields or pulse surface heating. High power processing is a necessary procedure to clean surface and improve the gradient. In the best tested X-band structures the achieved gradient is exceed 100 MV/m in of {approx}200 ns pulses for breakdown rate of {approx} 10{sup -7}. Gradient limit depends on number of factors and no one theory which can explain all sets of experimental results and predict gradient in new accelerating structure. In paper we briefly overview the recent experimental results of breakdown studies, progress in understanding of gradient limitations and scaling laws. Although superconducting rf technology has been adopted throughout the world for ILC, it has frequently been difficult to reach the predicted performance in these structures due to a number of factors: multipactoring, field emission, Q-slope, thermal breakdown. In paper we are discussing all these phenomena and the ways to increase accelerating gradient in SC cavity, which are a part of worldwide R&D program.

  10. Transverse wake field simulations for the ILC acceleration structure

    SciTech Connect

    Solyak, N.; Lunin, A.; Yakovlev, V.; /Fermilab

    2008-06-01

    Details of wake potential simulation in the acceleration structure of ILC, including the RF cavities and input/HOM couplers are presented. Transverse wake potential dependence is described versus the bunch length. Beam emittance dilution caused by main and HOM couplers is estimated, followed by a discussion of possible structural modifications allowing a reduction of transverse wake potential.

  11. Development of Transverse Modes Damped DLA Structure

    SciTech Connect

    Jing, C.; Kanareykin, A.; Schoessow, P.; Gai, W.; Konecny, R.; Power, J. G.; Conde, M.

    2009-01-22

    As the dimensions of accelerating structures become smaller and beam intensities higher, the transverse wakefields driven by the beam become quite large with even a slight misalignment of the beam from the geometric axis. These deflection modes can cause inter-bunch beam breakup and intra-bunch head-tail instabilities along the beam path, and thus BBU control becomes a critical issue. All new metal based accelerating structures, like the accelerating structures developed at SLAC or power extractors at CLIC, have designs in which the transverse modes are heavily damped. Similarly, minimizing the transverse wakefield modes (here the HEMmn hybrid modes in Dielectric-Loaded Accelerating (DLA) structures) is also very critical for developing dielectric based high energy accelerators. In this paper, we present the design of a 7.8 GHz transverse mode damped DLA structure currently under construction, along with plans for the experimental program.

  12. RF properties of periodic accelerating structures for linear colliders

    SciTech Connect

    Wang, J.W.

    1989-07-01

    With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e/sup /plus//e/sup /minus// physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs.

  13. Development of a 20 MeV Dielectric-Loaded Test Accelerator

    SciTech Connect

    Gold, S.H.; Kinkead, A.K.; Gai, W.; Power, J.G.; Konecny, R.; Jing, C.; Long, J.; Tantawi, S.G.; Nantista, C.D.; Fliflet, A.W.; Lombardi, M.; Lewis, D.; Bruce, R.W.; /Unlisted

    2007-04-13

    This paper presents a progress report on a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded test accelerator in the magnicon facility at NRL. The accelerator will be powered by an experimental 11.424-GHz magnicon amplifier that presently produces 25 MW of output power in a {approx}250-ns pulse at up to 10 Hz. The accelerator will include a 5-MeV electron injector originally developed at the Tsinghua University in Beijing, China, and can incorporate DLA structures up to 0.5 m in length. The DLA structures are being developed by ANL, and shorter test structures fabricated from a variety of dielectric materials have undergone testing at NRL at gradients up to {approx}8 MV/m. SLAC has developed components to distribute the power from the two magnicon output arms to the injector and to the DLA accelerating structure with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRL, has investigated means to join short ceramic sections into a continuous accelerator tube by a brazing process using an intense 83-GHz beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA test structure, and spectrometer, should take place within the next year.

  14. COAXIAL WIRE MEASUREMENTS IN NLC ACCELERATING STRUCTURES

    SciTech Connect

    Jones, Roger M

    2002-06-20

    The coaxial wire method provides an experimental way of measuring wake fields without the need for a particle beam. A special setup has been designed and is in the process of being fabricated at SLAC to measure the loss factors and synchronous frequencies of dipole modes in both traveling and standing wave structures for the Next Linear Collider (NLC). The method is described and predictions based on electromagnetic field simulations are discussed.

  15. Vacuum Insulator Development for the Dielectric Wall Accelerator

    SciTech Connect

    Harris, J R; Blackfield, D; Caporaso, G J; Chen, Y; Hawkins, S; Kendig, M; Poole, B; Sanders, D M; Krogh, M; Managan, J E

    2008-03-17

    At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using 'High Gradient Insulators' composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell.

  16. Accelerator-driven subcritical facility:Conceptual design development

    NASA Astrophysics Data System (ADS)

    Gohar, Yousry; Bolshinsky, Igor; Naberezhnev, Dmitry; Duo, Jose; Belch, Henry; Bailey, James

    2006-06-01

    A conceptual design development of an accelerator-driven subcritical facility has been carried out in the preparation of a joint activity with Kharkov Institute of Physics and Technology of Ukraine. The main functions of the facility are the medical isotope production and the support of the Ukraine nuclear industry. An electron accelerator is considered to drive the subcritical assembly. The neutron source intensity and spectrum have been studied. The energy deposition, spatial neutron generation, neutron utilization fraction, and target dimensions have been quantified to define the main target performance parameters, and to select the target material and beam parameters. Different target conceptual designs have been developed based the engineering requirements including heat transfer, thermal hydraulics, structure, and material issues. The subcritical assembly is designed to obtain the highest possible neutron flux level with a Keff of 0.98. Different fuel materials, uranium enrichments, and reflector materials are considered in the design process. The possibility of using low enrichment uranium without penalizing the facility performance is carefully evaluated. The mechanical design of the facility has been developed to maximize its utility and minimize the time for replacing the target and the fuel assemblies. Safety, reliability, and environmental considerations are included in the facility conceptual design. The facility is configured to accommodate future design improvements, upgrades, and new missions. In addition, it has large design margins to accommodate different operating conditions and parameters. In this paper, the conceptual design and the design analyses of the facility will be presented.

  17. Miniature penetrator (MinPen) acceleration recorder development test

    SciTech Connect

    Franco, R.J.; Platzbecker, M.R.

    1998-08-01

    The Telemetry Technology Development Department at Sandia National Laboratories actively develops and tests acceleration recorders for penetrating weapons. This new acceleration recorder (MinPen) utilizes a microprocessor-based architecture for operational flexibility while maintaining electronics and packaging techniques developed over years of penetrator testing. MinPen has been demonstrated to function in shock environments up to 20,000 Gs. The MinPen instrumentation development has resulted in a rugged, versatile, miniature acceleration recorder and is a valuable tool for penetrator testing in a wide range of applications.

  18. Design of High Gradient Accelerating Structure for CLIC

    NASA Astrophysics Data System (ADS)

    Grudiev, A.; Wuensch, W.

    2006-01-01

    A new CLIC main-linac accelerating-structure design, HDS (Hybrid Damped Structure), with improved high-gradient performance, efficiency and simplicity of fabrication is presented. The gains are achieved in part through a new cell design which includes fully-profiled rf surfaces optimized to minimize surface fields, and hybrid damping using both iris slots and radial waveguides. The slotted irises allow a simple structure fabrication in quadrants with no rf currents across joints, a reduced number of pieces per structure (only 4) and a reduced surface requiring precise machining. Further gains are achieved through a new structure optimization procedure, which simultaneously balances surface fields, power flow, short and long-range transverse wakefields and rf-to-beam efficiency. The optimization of a 30 GHz structure with a loaded accelerating gradient of 150 MV/m results in a bunch spacing of eight rf cycles and 31 % rf-to-beam efficiency.

  19. Accelerator and rf system development for NLC

    SciTech Connect

    Vlieks, A.E.; Callin, R.; Deruyter, H.

    1993-04-01

    An experimental station for an X-band Next Linear Collider has been constructed at SLAC. This station consists of a klystron and modulator, a low-loss waveguide system for rf power distribution, a SLED II pulse-compression and peak-power multiplication system, acceleration sections and beam-line components (gun, prebuncher, preaccelerator, focussing elements and spectrometer). An extensive program of experiments to evaluate the performance of all components is underway. The station is described in detail in this paper, and results to date are presented.

  20. Two-beam, Multi-mode Detuned Accelerating Structure

    SciTech Connect

    Kazakov, S. Yu.; Kuzikov, S. V.; Yakovlev, V. P.; Hirshfield, J. L.

    2009-01-22

    A two-beam accelerator structure is described having several novel features including all metal construction, no transfer structures required between the drive and accelerator channels, symmetric fields at the axes of each channel, RF micropulse widths on cavity irises that are less than half those for a conventional cavity at the same fundamental frequency by virtue of using several harmonically-related cavity modes, and a transformer ratio much greater than unity by the use of detuned cavities. Detuning is also shown to allow either parallel or anti-parallel directions for the drive and accelerated beams. A preliminary calculation for the dilution of emittance due to short-range wakes for drive beam parameters similar to those for CLIC shows this effect to be acceptably small.

  1. Development of a Compact Dielectric-Loaded Test Accelerator at 11.4 GHz

    SciTech Connect

    Gold, S. H.; Fliflet, A. W.; Kinkead, A. K.; Gai, W.; Power, J. G.; Konecny, R.; Jing, C.

    2009-01-22

    This paper presents a progress report on the development of a dielectric-loaded test accelerator in the Magnicon Facility at the Naval Research Laboratory (NRL). The accelerator will be powered by an 11.4-GHz magnicon amplifier that provides up to 25 MW of output power in a {approx}250-ns pulse at up to 10 Hz. The accelerator includes a 5-MeV electron injector originally developed at the Tsinghua University in Beijing, China, and can incorporate dielectric-loaded accelerating (DLA) structures of up to 0.5 m in length. The DLA structures are being developed by Argonne National Laboratory and Euclid Techlabs, and shorter test structures fabricated from a variety of dielectric materials have undergone rf testing at NRL at accelerating gradients up to 15 MV/m. The first stage of the accelerator, including the 5-MeV injector, has recently begun operation, and initial operation of the complete dielectric-loaded test accelerator, including injector, DLA test structure, and spectrometer, should take place within the next year.

  2. Observation of multipactor suppression in a dielectric-loaded accelerating structure using an applied axial magnetic field

    SciTech Connect

    Jing, C.; Konecny, R.; Antipov, S.; Chang, C.; Gold, S. H.; Schoessow, P.; Kanareykin, A.; Gai, W.

    2013-11-18

    Efforts by a number of institutions to develop a Dielectric-Loaded Accelerating (DLA) structure capable of supporting high gradient acceleration when driven by an external radio frequency source have been ongoing over the past decade. Single surface resonant multipactor has been previously identified as one of the major limitations on the practical application of DLA structures in electron accelerators. In this paper, we report the results of an experiment that demonstrated suppression of multipactor growth in an X-band DLA structure through the use of an applied axial magnetic field. This represents an advance toward the practical use of DLA structures in many accelerator applications.

  3. Development of compact linear accelerator in KBSI

    SciTech Connect

    Yoon, Jang-Hee; Lee, Byoung-Seob; Choi, Seyong; Park, Jin Yong; Ok, Jung-Woo; Won, Mi-Sook

    2012-02-15

    The compact linear accelerator using a 28 GHz ECRIS is under construction in KBSI, South Korea. The main capability of this facility is the production of fast neurons for the neutron radiography. The designing of a superconducting magnet, microwave transmission system, beam extraction, and plasma chamber of ECRIS were finished. The nominal axial design fields of the magnets are 3.6 T at injection and 2.2 T at extraction; the nominal radial design field strength at the plasma chamber wall is 2.1 T. We already installed 10 kW, 28 GHz gyrotron, and tested a microwave power from gyrotron using a dummy load. The current status will be discussed in this paper.

  4. Development of compact linear accelerator in KBSI.

    PubMed

    Yoon, Jang-Hee; Lee, Byoung-Seob; Choi, Seyong; Park, Jin Yong; Ok, Jung-Woo; Won, Mi-Sook

    2012-02-01

    The compact linear accelerator using a 28 GHz ECRIS is under construction in KBSI, South Korea. The main capability of this facility is the production of fast neurons for the neutron radiography. The designing of a superconducting magnet, microwave transmission system, beam extraction, and plasma chamber of ECRIS were finished. The nominal axial design fields of the magnets are 3.6 T at injection and 2.2 T at extraction; the nominal radial design field strength at the plasma chamber wall is 2.1 T. We already installed 10 kW, 28 GHz gyrotron, and tested a microwave power from gyrotron using a dummy load. The current status will be discussed in this paper.

  5. Development of compact linear accelerator in KBSIa)

    NASA Astrophysics Data System (ADS)

    Yoon, Jang-Hee; Lee, Byoung-Seob; Choi, Seyong; Park, Jin Yong; Ok, Jung-Woo; Won, Mi-Sook

    2012-02-01

    The compact linear accelerator using a 28 GHz ECRIS is under construction in KBSI, South Korea. The main capability of this facility is the production of fast neurons for the neutron radiography. The designing of a superconducting magnet, microwave transmission system, beam extraction, and plasma chamber of ECRIS were finished. The nominal axial design fields of the magnets are 3.6 T at injection and 2.2 T at extraction; the nominal radial design field strength at the plasma chamber wall is 2.1 T. We already installed 10 kW, 28 GHz gyrotron, and tested a microwave power from gyrotron using a dummy load. The current status will be discussed in this paper.

  6. Acceleration of stable interface structure searching using a kriging approach

    NASA Astrophysics Data System (ADS)

    Kiyohara, Shin; Oda, Hiromi; Tsuda, Koji; Mizoguchi, Teruyasu

    2016-04-01

    Crystalline interfaces have a tremendous impact on the properties of materials. Determination of the atomic structure of the interface is crucial for a comprehensive understanding of the interface properties. Despite this importance, extensive calculation is necessary to determine even one interface structure. In this study, we apply a technique called kriging, borrowed from geostatistics, to accelerate the determination of the interface structure. The atomic structure of simplified coincidence-site lattice interfaces were determined using the kriging approach. Our approach successfully determined the most stable interface structure with an efficiency almost 2 orders of magnitude better than the traditional “brute force” approach.

  7. Fine structure of auroral particle acceleration

    SciTech Connect

    Lynch, K.A.

    1992-01-01

    A mass-analyzing capped hemispherical electrostatic analyzer was developed for the purpose of resolving the mass, energy, and pitch angle distributions of auroral ions. The instrument, the B-field Hemispherical Electrostatic Energy and Pitch Angle Spectrometer (BEEPS), is an extension of the HEEPS instrument, which uses a hemispherical analyzer and microchannel plates to measure the angular and energy distribution of ions. BEEPS uses a toroidal magnetic field constructed from rare-earth permanent magnets to separate ion measurements into two groups, protons and heavier ions. BEEPS was flown in February, 1991, from Poker Flat, Alaska, on the TOPAZ3 sounding rocket. This sounding rocket mission carried a full array of particle and field instrumentation to an altitude of over 1000 km. Electron data from the flight are presented and discussed in detail, and are shown in light of both ion and wave data taken during the same flight. Correspondences between the various data sets are presented. Particular note is made of the observation that ion heating seems to correspond with a field-aligned plateau in the electron distribution function below the peak electron energy. The growth rate of the n = -1 anomalous Doppler resonance of medium energy electrons with lower hybrid waves is discussed, and proposed as a mechanism for converting energy from the auroral electrons, the driver of the auroral activity, to the ion heating events.

  8. Structure of Accelerated Learning Program (ALP) Efforts, 2000-01.

    ERIC Educational Resources Information Center

    Baenen, Nancy; Yaman, Kimberly

    This report focuses on the structure of instructional assistance available through the Accelerated Learning Program (ALP) to students who show low achievement in the Wake County Public School System (WCPSS), North Carolina. Context information is also provided on other programs available to these students. Reports on ALP student participation,…

  9. RF ACCELERATING STRUCTURE FOR THE MUON COOLING EXPERIMENT.

    SciTech Connect

    CORLETT,J.; GREEN,M.; LI,D.; HOLTKAMP,N.; MORETTI,A.; KIRK,H.G.; PALMER,R.B.; ZHAO,Y.; SUMMERS,D.

    1999-03-29

    The ionization cooling of muons requires longitudinal acceleration of the muons after scattering in a hydrogen target. In order to maximize the accelerating voltage, we propose using linear accelerating structures with cells bounded by thin beryllium metal foils. This produces an on-axis field equivalent to the maximum surface field, whereas with beam-pipes the accelerating field is approximately half that of the peak surface field in the cavity. The muons interact only weakly with the thin foils. A {pi}/2 interleaved cavity structure has been chosen, with alternate cells coupled together externally, and the two groups of cells fed in quadrature. At present they are considering an operating temperature of 77K to gain a factor of at least two in Q-value over room temperature. The authors describe the design of the {pi}/2 interleaved cavity structure, design of an alternative {pi}-mode open structure, preliminary experimental results from a low-power test cavity, and plans for high-power testing.

  10. Two-Channel Rectangular Dielectric Wake Field Accelerator Structure Experiment

    SciTech Connect

    Sotnikov, G. V.; Marshall, T. C.; Shchelkunov, S. V.; Didenko, A.; Hirshfield, J. L.

    2009-01-22

    A design is presented for a two-channel 30-GHz rectangular dielectric wake field accelerator structure being built for experimental tests at Argonne National Laboratory (ANL). This structure allows for a transformer ratio T much greater than two, and permits continuous coupling of energy from drive bunches to accelerated bunches. It consists of three planar slabs of cordierite ceramic ({epsilon} = 4.7) supported within a rectangular copper block, forming a drive channel 12 mmx6 mm, and an accelerator channel 2 mmx6 mm. When driven by a 50 nC, 14 MeV single bunch available at ANL, theory predicts an acceleration field of 6 MeV/m, and T = 12.6. Inherent transverse wake forces introduce deflections and some distortion of bunch profiles during transit through the structure that are estimated to be tolerable. Additionally, a cylindrical two-channel DWFA is introduced which shares many advantages of the rectangular structure including high T, and the added virtue of axisymmetry that eliminates lowest-order transverse deflecting forces.

  11. Comparisons of radio frequency technology for superconducting accelerating structures

    NASA Astrophysics Data System (ADS)

    Kimber, Andrew J.

    2015-12-01

    Since the introduction of radiofrequency (RF) accelerating cavities, normal conducting as well as superconducting, there has been a need to drive them with RF power. At first glance, the function of an RF drive system may seem simple and straightforward, but this belies subtleties that greatly affect the performance of the cavity itself, diminishing efforts in perfecting techniques in design and manufacture. It can also contribute to a significant portion of the initial capital and ongoing running costs of a facility, maintenance labor, downtime and future expenditure as the system ages. The RF `system', should be thought of as just that, the entire collection of components from wall plug to cavity. Following this integrated approach will enable the system to meet or exceed its design goals. This paper seeks to review the current state of RF technology for superconducting structures and to compare these technologies, looking at what has traditionally been used, developments that have enabled higher efficiencies and higher reliabilities as well as looking towards future technologies. It will concentrate on superconducting applications, but much of the narrative is equally applicable to normal conducting structures as well.

  12. Ion Bombardment of Microprotrusions in High Gradient Accelerating Structures

    SciTech Connect

    Nusinovich, Gregory S.; Kashyn, Dmytro; Antonsen, Thomas Jr.; Haber, Irving

    2010-11-04

    This paper starts from a brief overview of theoretical studies of high-gradient accelerating structures at the University of Maryland. The rest of the paper is devoted to the analysis of ion bombardment of small protrusions in such structures. First, this problem is studied analytically. Then, some results of particle-in-cell simulations performed with the use of code WARP are presented and discussed.

  13. Improved input and output couplers for SC acceleration structure

    SciTech Connect

    Solyak, N.; Gonin, I.; Latina, A.; Lunin, A.; Poloubotko, V.; Yakovlev, V.; /Fermilab

    2009-04-01

    Different couplers are described that allow the reduction of both transverse wake potential and RF kick in the SC acceleration structure of ILC. A simple rotation of the couplers reducing the RF kick and transverse wake kick is discussed for both the main linac and bunch compressors, along with possible limitations of this method. Designs of a coupler unit are presented which preserve axial symmetry of the structure, and provide reduced both the RF kick and transverse wake field.

  14. Calculation of structural dynamic forces and stresses using mode acceleration

    NASA Technical Reports Server (NTRS)

    Blelloch, Paul

    1989-01-01

    While the standard mode acceleration formulation in structural dynamics has often been interpreted to suggest that the reason for improved convergence obtainable is that the dynamic correction factor is divided by the modal frequencies-squared, an alternative formulation is presented which clearly indicates that the only difference between mode acceleration and mode displacement data recovery is the addition of a static correction term. Attention is given to the advantages in numerical implementation associated with this alternative, as well as to an illustrative example.

  15. Developing of superconducting niobium cavities for accelerators

    NASA Astrophysics Data System (ADS)

    Pobol, I. L.; Yurevich, S. V.

    2015-11-01

    The results of a study of structure and mechanical properties of welding joints, superconducting characteristics of the material after joining of welded components of superconducting radio frequency cavities are presented. The paper also describes the results of testing of the RF 1.3 GHz single-cell niobium cavity manufactured in the PTI NAS Belarus.

  16. On radiative acceleration in spine-sheath structured blazar jets

    NASA Astrophysics Data System (ADS)

    Chhotray, A.; Nappo, F.; Ghisellini, G.; Salafia, O. S.; Tavecchio, F.; Lazzati, D.

    2017-04-01

    It has been proposed that blazar jets are structured, with a fast spine surrounded by a slower sheath or layer. This structured jet model explains some properties of their emission and morphology. Because of their relative motion, the radiation produced by one component is seen amplified by the other, thus enhancing the inverse Compton emission of both. Radiation is emitted anisotropically in the comoving frames and causes the emitting plasma to recoil. As seen in the observer frame, this corresponds to a deceleration of the fastest component (the spine) and an acceleration of the slower one (the layer). While the deceleration of the spine has already been investigated, here we study for the first time the acceleration of the sheath and find self-consistent velocity profile solutions for both the spine and the sheath while accounting for radiative cooling. We find that the sheath can be accelerated to the velocities required by the observations if its leptons remain energetic in the acceleration region, assumed to be of the order of ∼100 Schwarzschild radii, demanding continuous injection of energetic particles in that region.

  17. Computational Tools for Accelerating Carbon Capture Process Development

    SciTech Connect

    Miller, David; Sahinidis, N V; Cozad, A; Lee, A; Kim, H; Morinelly, J; Eslick, J; Yuan, Z

    2013-06-04

    This presentation reports development of advanced computational tools to accelerate next generation technology development. These tools are to develop an optimized process using rigorous models. They include: Process Models; Simulation-Based Optimization; Optimized Process; Uncertainty Quantification; Algebraic Surrogate Models; and Superstructure Optimization (Determine Configuration).

  18. Sulfated Glycosaminoglycans Accelerate Transthyretin Amyloidogenesis by Quaternary Structural Conversion†

    PubMed Central

    Bourgault, Steve; Solomon, James P.; Reixach, Natàlia; Kelly, Jeffery W.

    2011-01-01

    Glycosaminoglycans (GAGs), which are found in association with all extracellular amyloid deposits in humans, are known to accelerate the aggregation of various amyloidogenic proteins in vitro. However, the precise molecular mechanism(s) by which GAGs accelerate amyloidogenesis remains elusive. Herein, we show that sulfated GAGs, especially heparin, accelerate transthyretin (TTR) amyloidogenesis by quaternary structural conversion. The clustering of sulfate groups on heparin and its polymeric nature are essential features for accelerating TTR amyloidogenesis. Heparin does not influence TTR tetramer stability or TTR dissociation kinetics, nor does it alter the folded monomer – misfolded monomer equilibrium directly. Instead, heparin accelerates the conversion of preformed TTR oligomers into larger aggregates. The more rapid disappearance of monomeric TTR in the presence of heparin likely reflects the fact that the monomer–misfolded amyloidogenic monomer–oligomer–TTR fibril equilibria are all linked—a hypothesis that is strongly supported by the light scattering data. TTR aggregates prepared in presence of heparin showed a higher resistance to trypsin and proteinase K proteolysis and a lower exposure of hydrophobic side chains comprising hydrophobic clusters, suggesting an active role in amyloidogenesis. Our data suggest that heparin accelerates TTR aggregation by a scaffold-based mechanism, in which the sulfate groups comprising GAGs interact primarily with TTR oligomers through electrostatic interactions, concentrating and orienting the oligomers, facilitating the formation of higher molecular weight aggregates. This model raises the possibility that GAGs may play a protective role in human amyloid diseases by interacting with proteotoxic oligomers and promoting their association into less toxic amyloid fibrils. PMID:21194234

  19. Stacked subsea templates accelerate deepwater development

    SciTech Connect

    Ramsey, J.F.; Blincow, R.M.; Pickard, R.D. )

    1991-10-21

    This paper reports on a deepwater project that can be brought on-line more quickly because of stackable drilling and production templates. Historically, one of the primary barriers to the economic development of deepwater reserves has been the long lead time from discovery to first production. Typically, production facilities must be built and often installed before development wells are drilled. The use of three-slot drilling templates allows development drilling to proceed while the production templates, Christmas trees, flow lines, and production platform are constructed. Thus, the time from initial investment to first revenue reduced. Enserch Exploration Inc., along with partners Petrofina Delaware Inc. and AGIP Petroleum, is using a piggy-back or transportable stacked template system to develop deepwater gas reserves in Mississippi Canyon Block 441, approximately 50 miles south of Grand Isle, La. The discovery is located in 1,410-1,520 ft of water. The Louisiana Offshore Oil Port (LOOP) safety fairway running north to south covers the eastern three fourths of Mississippi Canyon Block 441 and rules out surface production facilities over the well locations.

  20. Enhanced Ion Acceleration from Micro-tube Structured Targets

    NASA Astrophysics Data System (ADS)

    Snyder, Joseph; Ji, Liangliang; Akli, Kramer

    2015-11-01

    We present an enhanced ion acceleration method that leverages recent advancements in 3D printing for target fabrication. Using the three-dimensional Particle-in-Cell simulation code Virtual Laser-Plasma Lab (VLPL), we model the interaction of a short pulse, high intensity laser with a micro-tube plasma (MTP) structured target. When compared to flat foils, the MTP target enhances the maximum proton energy by a factor of about 4. The ion enhancement is attributed to two main factors: high energy electrons extracted from the tube structure enhancing the accelerating field and light intensification within the MTP target increasing the laser intensity at the location of the foil. We also present results on ion energy scaling with micro-tube diameter and incident laser pulse intensity. This work was supported by the AFOSR under contract No. FA9550-14-1-0085.

  1. Computational Tools to Accelerate Commercial Development

    SciTech Connect

    Miller, David C

    2013-01-01

    The goals of the work reported are: to develop new computational tools and models to enable industry to more rapidly develop and deploy new advanced energy technologies; to demonstrate the capabilities of the CCSI Toolset on non-proprietary case studies; and to deploy the CCSI Toolset to industry. Challenges of simulating carbon capture (and other) processes include: dealing with multiple scales (particle, device, and whole process scales); integration across scales; verification, validation, and uncertainty; and decision support. The tools cover: risk analysis and decision making; validated, high-fidelity CFD; high-resolution filtered sub-models; process design and optimization tools; advanced process control and dynamics; process models; basic data sub-models; and cross-cutting integration tools.

  2. Status of high temperature superconductor development for accelerator magnets

    NASA Technical Reports Server (NTRS)

    Hirabayashi, H.

    1995-01-01

    High temperature superconductors are still under development for various applications. As far as conductors for magnets are concerned, the development has just been started. Small coils wound by silver sheathed Bi-2212 and Bi-2223 oxide conductors have been reported by a few authors. Essential properties of high T(sub c) superconductors like pinning force, coherent length, intergrain coupling, weak link, thermal property, AC loss and mechanical strength are still not sufficiently understandable. In this talk, a review is given with comparison between the present achievement and the final requirement for high T(sub c) superconductors, which could be particularly used in accelerator magnets. Discussions on how to develop high T(sub c) superconductors for accelerator magnets are included with key parameters of essential properties. A proposal of how to make a prototype accelerator magnet with high T(sub c) superconductors with prospect for future development is also given.

  3. Accelerated larvae development of Ascaris lumbricoides eggs with ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Aladawi, M. A.; Albarodi, H.; Hammoudeh, A.; Shamma, M.; Sharabi, N.

    2006-01-01

    In order to investigate the effect of UV radiation on the development of Ascaris lumbricoides larvae, eggs were exposed to increasing UV doses. Filtered wastewater from the secondary effluent taken from the Damascus wastewater treatment plant (DWTP) was used as irradiation and incubation medium. The progressive and accelerated embryonation stages were microscopically observed and the percentages of completely developed larvae were determined weekly. Results indicated that the UV radiation accelerated the development of larvae with increasing UV dose. Preliminary information about the relationship between the UV radiation dose and rate of embryonation is also presented.

  4. Space Launch System Accelerated Booster Development Cycle

    NASA Technical Reports Server (NTRS)

    Arockiam, Nicole; Whittecar, William; Edwards, Stephen

    2012-01-01

    With the retirement of the Space Shuttle, NASA is seeking to reinvigorate the national space program and recapture the public s interest in human space exploration by developing missions to the Moon, near-earth asteroids, Lagrange points, Mars, and beyond. The would-be successor to the Space Shuttle, NASA s Constellation Program, planned to take humans back to the Moon by 2020, but due to budgetary constraints was cancelled in 2010 in search of a more "affordable, sustainable, and realistic" concept2. Following a number of studies, the much anticipated Space Launch System (SLS) was unveiled in September of 2011. The SLS core architecture consists of a cryogenic first stage with five Space Shuttle Main Engines (SSMEs), and a cryogenic second stage using a new J-2X engine3. The baseline configuration employs two 5-segment solid rocket boosters to achieve a 70 metric ton payload capability, but a new, more capable booster system will be required to attain the goal of 130 metric tons to orbit. To this end, NASA s Marshall Space Flight Center recently released a NASA Research Announcement (NRA) entitled "Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction." The increased emphasis on affordability is evident in the language used in the NRA, which is focused on risk reduction "leading to an affordable Advanced Booster that meets the evolved capabilities of SLS" and "enabling competition" to "enhance SLS affordability. The purpose of the work presented in this paper is to perform an independent assessment of the elements that make up an affordable and realistic path forward for the SLS booster system, utilizing advanced design methods and technology evaluation techniques. The goal is to identify elements that will enable a more sustainable development program by exploring the trade space of heavy lift booster systems and focusing on affordability, operability, and reliability at the system and subsystem levels5. For this study

  5. Superconducting accelerating structures for very low velocity ion beams

    SciTech Connect

    Xu, J.; Shepard, K.W.; Ostroumov, P.N.; Fuerst, J.D.; Waldschmidt, G.; Gonin, I.V.; /Fermilab

    2008-01-01

    This paper presents designs for four types of very-low-velocity superconducting accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006 < v/c < 0.06. Superconducting TEM-class cavities have been widely applied to CW acceleration of ion beams. SC linacs can be formed as an array of independently-phased cavities, enabling a variable velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the US and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front-end of such linacs, particularly for the post-acceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008 < {beta} = v/c < 0.05 were developed about two decades ago and have been successfully operated at the ATLAS SC linac at Argonne National Laboratory. Since that time, progress in simulation tools, cavity fabrication and processing have increased SC cavity gradients by a factor of 3-4. This paper applies these tools to optimize the design of a four-gap quarter-wave resonator for exotic beam facilities and other low-velocity applications.

  6. An accelerated fusion power development plan

    NASA Astrophysics Data System (ADS)

    Dean, Stephen O.; Baker, Charles C.; Cohn, Daniel R.; Kinkead, Susan D.

    1991-06-01

    Energy for electricity and transportation is a national issue with worldwide environmental and political implications. The world must have energy options for the next century that are not vulnerable to possible disruption for technical, environmental, public confidence, or other reasons. Growing concerns about the greenhouse effect and the safety of transporting oil may lead to reduced burning of coal and other fossil fuels, and the incidents at Three Mile Island and Chernobyl, as well as nuclear waste storage problems, have eroded public acceptance of nuclear fission. Meeting future world energy needs will require improvements in energy efficiency and conservation. However, the world will soon need new central station power plants and increasing amounts of fuel for the transportation sector. The use of fossil fuels, and possibly even fission power, will very likely be restricted because of environmental, safety, and, eventually, supply considerations. Time is running out for policymakers. New energy technologies cannot be brought to the marketplace overnight. Decades are required to bring a new energy production technology from conception to full market penetration. With the added urgency to mitigate deleterious environmental effects of energy use, policymakers must act decisively now to establish and support vigorous energy technology development programs. The U.S. has invested 8 billion over the past 40 years in fusion research and development. If the U.S. fusion program proceeds according to its present strategy, an additional 40 years, and more money, will be expended before fusion will provide commercial electricity. Such an extended schedule is neither cost-effective nor technically necessary. It is time to launch a national venture to construct and operate a fusion power pilot plant. Such a plant could be operational within 15 years of a national commitment to proceed.

  7. Accelerating Leadership Development via Immersive Learning and Cognitive Apprenticeship

    ERIC Educational Resources Information Center

    Backus, Clark; Keegan, Kevin; Gluck, Charles; Gulick, Lisa M. V.

    2010-01-01

    The authors put forward an approach to leadership development that builds on the principle of accelerated learning. They argue that leadership development, particularly in a period of recession or slow economic growth, needs to deliver results more quickly and with fewer resources. Indeed, they raise the question of whether or not this is what is…

  8. No Time To Kill: Entrainment and Accelerating Courseware Development.

    ERIC Educational Resources Information Center

    Millington, Paula Crnkovich

    This paper examines the concept of time in multimedia, World Wide Web-based courseware development. The biological concept of entrainment (the alignment of rhythms within and between systems) to accelerate courseware development is explored. The discussion begins with the foundational concepts of entrainment from biological systems and social…

  9. On the resonant behavior of laminated accelerating structures

    NASA Astrophysics Data System (ADS)

    Ivanyan, M. I.; Avagyan, V. Sh.; Danielyan, V. A.; Tsakanian, A. V.; Vardanyan, A. S.; Zakaryan, V. S.

    2017-03-01

    The laminated round metallic waveguide is one of the promising options for high frequency single-mode accelerating structures. Under certain conditions the longitudinal impedance of such type structures has a narrow-band resonance that corresponds to slowly propagating synchronous TM01 fundamental mode. In this paper the resonant properties of two parallel plates and rectangular cavity with laminated walls are studied. The first measurement results performed for the copper cavity of rectangular cross section with inner germanium layers at top and bottom walls are presented. The measurements show the existence of a dedicated resonant frequency being in a good agreement with the one predicted for the corresponding laminated parallel plates.

  10. Development of wide area environment accelerator operation and diagnostics method

    NASA Astrophysics Data System (ADS)

    Uchiyama, Akito; Furukawa, Kazuro

    2015-08-01

    Remote operation and diagnostic systems for particle accelerators have been developed for beam operation and maintenance in various situations. Even though fully remote experiments are not necessary, the remote diagnosis and maintenance of the accelerator is required. Considering remote-operation operator interfaces (OPIs), the use of standard protocols such as the hypertext transfer protocol (HTTP) is advantageous, because system-dependent protocols are unnecessary between the remote client and the on-site server. Here, we have developed a client system based on WebSocket, which is a new protocol provided by the Internet Engineering Task Force for Web-based systems, as a next-generation Web-based OPI using the Experimental Physics and Industrial Control System Channel Access protocol. As a result of this implementation, WebSocket-based client systems have become available for remote operation. Also, as regards practical application, the remote operation of an accelerator via a wide area network (WAN) faces a number of challenges, e.g., the accelerator has both experimental device and radiation generator characteristics. Any error in remote control system operation could result in an immediate breakdown. Therefore, we propose the implementation of an operator intervention system for remote accelerator diagnostics and support that can obviate any differences between the local control room and remote locations. Here, remote-operation Web-based OPIs, which resolve security issues, are developed.

  11. DEVELOPMENT OF A COMPACT RADIOGRAPHY ACCELERATOR USING DIELECTRIC WALL ACCELERATOR TECHNOLOGY

    SciTech Connect

    Sampayan, S; Caporaso, G; Chen, Y; Hawkins, S; Holmes, C; Krogh, M; McCarrick, J; Nelson, S; Nunnally, W; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2005-06-02

    We are developing an inexpensive compact accelerator system primarily intended for pulsed radiography. Design characteristics are an 8 MeV endpoint energy, 2 kA beam current, a cell gradient of approximately 3 MV/m (for an overall accelerator length is 2-3 m), and <$1/Volt capital costs. Such designs have been made possible with the development of high specific energy dielectrics (>10J/cm{sup 3}), specialized transmission line designs and multi-gap laser triggered low jitter (<1 ns) gas switches. In this geometry, the pulse forming lines, switches, and insulator/beam pipe are fully integrated within each cell to form a compact, stand-alone, stackable unit. We detail our research and modeling to date, recent high voltage test results, and the integration concept of the cells into a radiographic system.

  12. Dark Current Simulation for Linear Collider Accelerator Structures

    SciTech Connect

    Ng, C.K.; Li, Z.; Zhan, X.; Srinivas, V.; Wang, J.; Ko, K.; /SLAC

    2011-08-25

    The dynamics of field-emitted electrons in the traveling wave fields of a constant gradient (tapered) disk-loaded waveguide is followed numerically. Previous simulations have been limited to constant impedance (uniform) structures for sake of simplicity since only the fields in a unit cell is needed. Using a finite element field solver on a parallel computer, the fields in the tapered structure can now be readily generated. We will obtain the characteristics of the dark current emitted from both structure types and compare the two results with and without the effect of secondary electrons. The NLC and JLC detuned structures are considered to study if dark current may pose a problem for high gradient acceleration in the next generation of Linear Colliders.

  13. On the relationship between collisionless shock structure and energetic particle acceleration

    NASA Technical Reports Server (NTRS)

    Kennel, C. F.

    1983-01-01

    Recent experimental research on bow shock structure and theoretical studies of quasi-parallel shock structure and shock acceleration of energetic particles were reviewed, to point out the relationship between structure and particle acceleration. The phenomenological distinction between quasi-parallel and quasi-perpendicular shocks that has emerged from bow shock research; present efforts to extend this work to interplanetary shocks; theories of particle acceleration by shocks; and particle acceleration to shock structures using multiple fluid models were discussed.

  14. Accelerating Child Survival and Development in Dark Times.

    ERIC Educational Resources Information Center

    Grant, James P.

    Measures were proposed that would enable UNICEF, in association with others and despite prevailing difficult economic circumstances, to more effectively bring well-being and hope to hundreds of millions of children. Specific proposals were designed to help most countries accelerate child survival and development. Most particularly, it was…

  15. Accelerating Early Language Development with Multi-Sensory Training

    ERIC Educational Resources Information Center

    Bjorn, Piia M.; Kakkuri, Irma; Karvonen, Pirkko; Leppanen, Paavo H. T.

    2012-01-01

    This paper reports the outcome of a multi-sensory intervention on infant language skills. A programme titled "Rhyming Game and Exercise Club", which included kinaesthetic-tactile mother-child rhyming games performed in natural joint attention situations, was intended to accelerate Finnish six- to eight-month-old infants' language development. The…

  16. Simulation of variation characteristics at thermostabilization of 27 GHz biperiodical accelerating structure

    NASA Astrophysics Data System (ADS)

    Kluchevskaya, Y. D.; Polozov, S. M.

    2016-07-01

    It was proposed to develop the biperiodical accelerating structure with operating frequency of 27 GHz to assess the possibility of design a compact accelerating structure for medical application. It is necessary to do the more careful simulation of variation characteristics this case because of decrease of wavelength 3-10 times in comparison with conventional structures 10 and 3 cm ranges. Results of such study are presented in the article. Also a combination of high electromagnetic fields and long pulses at a high operating frequency leads to the temperature increase in the structure, thermal deformation and significant change of the resonator characteristics, including the frequency of the RF pulse. Development results of three versions of system of temperature stabilization also discuses.

  17. Prompt Gas Desorption Due to Ion Impact on Accelerator Structures

    NASA Astrophysics Data System (ADS)

    Vijay, Sagar; Seidl, Peter A.; Faltens, Andy; Lidia, Steven M.

    2011-10-01

    The repetition rate and peak current of high intensity ion accelerators for inertial fusion or other applications may be limited under certain conditions by the desorption of gas molecules and atoms due to stray ions striking the accelerator structure. We have measured the prompt yield of atoms in close proximity to the point of impact of the ions on a surface. Using the 300-keV, K+ ion beam of the Neutralized Drift Compression Experiment (NDCX-I), ions strike a metal target in a 5-10 microsecond bunch. The collector of a Bayert-Alpert style ionization gauge is used to detect the local pressure burst several centimeters away. Pressure transients are observed on a micro-second time scale due to the initial burst of desorbed gas, and on a much longer (~1 second) timescale, corresponding to the equilibration of the pressure after many ``bounces'' of atoms in the vacuum chamber. We report on these time dependent pressure measurements, modeling of the pressure transient, and implications for high-intensity ion accelerators. Work performed under auspices of U.S. DOE by LBNL under Contract DE-AC02-05CH1123.

  18. Advanced low-beta cavity development for proton and ion accelerators

    NASA Astrophysics Data System (ADS)

    Conway, Z. A.; Kelly, M. P.; Ostroumov, P. N.

    2015-05-01

    Recent developments in designing and processing low-beta superconducting cavities at Argonne National Laboratory are very encouraging for future applications requiring compact proton and ion accelerators. One of the major benefits of these accelerating structures is achieving real-estate accelerating gradients greater than 3 MV/m very efficiently either continuously or for long-duty cycle operation (>1%). The technology has been implemented in low-beta accelerator cryomodules for the Argonne ATLAS heavy-ion linac where the cryomodules are required to have real-estate gradients of more than 3 MV/m. In offline testing low-beta cavities with even higher gradients have already been achieved. This paper will review this work where we have achieved surface fields greater than 166 mT magnetic and 117 MV/m electric in a 72 MHz quarter-wave resonator optimized for β = 0.077 ions.

  19. Studying Radiation Damage in Structural Materials by Using Ion Accelerators

    NASA Astrophysics Data System (ADS)

    Hosemann, Peter

    2011-02-01

    Radiation damage in structural materials is of major concern and a limiting factor for a wide range of engineering and scientific applications, including nuclear power production, medical applications, or components for scientific radiation sources. The usefulness of these applications is largely limited by the damage a material can sustain in the extreme environments of radiation, temperature, stress, and fatigue, over long periods of time. Although a wide range of materials has been extensively studied in nuclear reactors and neutron spallation sources since the beginning of the nuclear age, ion beam irradiations using particle accelerators are a more cost-effective alternative to study radiation damage in materials in a rather short period of time, allowing researchers to gain fundamental insights into the damage processes and to estimate the property changes due to irradiation. However, the comparison of results gained from ion beam irradiation, large-scale neutron irradiation, and a variety of experimental setups is not straightforward, and several effects have to be taken into account. It is the intention of this article to introduce the reader to the basic phenomena taking place and to point out the differences between classic reactor irradiations and ion irradiations. It will also provide an assessment of how accelerator-based ion beam irradiation is used today to gain insight into the damage in structural materials for large-scale engineering applications.

  20. Observation of Wakefield Suppression in a Photonic-Band-Gap Accelerator Structure.

    PubMed

    Simakov, Evgenya I; Arsenyev, Sergey A; Buechler, Cynthia E; Edwards, Randall L; Romero, William P; Conde, Manoel; Ha, Gwanghui; Power, John G; Wisniewski, Eric E; Jing, Chunguang

    2016-02-12

    We report experimental observation of higher order mode (HOM) wakefield suppression in a room-temperature traveling-wave photonic-band-gap (PBG) accelerating structure at 11.700 GHz. It has been long recognized that PBG structures have the potential for reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in a room-temperature PBG structure was conducted in 2005. Since then, the importance of PBG accelerator research has been recognized by many institutions. However, the full experimental characterization of the wakefield spectrum and demonstration of wakefield suppression when the accelerating structure is excited by an electron beam has not been performed to date. We conducted an experiment at the Argonne Wakefield Accelerator test facility and observed wakefields excited by a single high charge electron bunch when it passes through a PBG accelerator structure. Excellent HOM suppression properties of the PBG accelerator were demonstrated in the beam test.

  1. Observation of Wakefield Suppression in a Photonic-Band-Gap Accelerator Structure

    NASA Astrophysics Data System (ADS)

    Simakov, Evgenya I.; Arsenyev, Sergey A.; Buechler, Cynthia E.; Edwards, Randall L.; Romero, William P.; Conde, Manoel; Ha, Gwanghui; Power, John G.; Wisniewski, Eric E.; Jing, Chunguang

    2016-02-01

    We report experimental observation of higher order mode (HOM) wakefield suppression in a room-temperature traveling-wave photonic-band-gap (PBG) accelerating structure at 11.700 GHz. It has been long recognized that PBG structures have the potential for reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in a room-temperature PBG structure was conducted in 2005. Since then, the importance of PBG accelerator research has been recognized by many institutions. However, the full experimental characterization of the wakefield spectrum and demonstration of wakefield suppression when the accelerating structure is excited by an electron beam has not been performed to date. We conducted an experiment at the Argonne Wakefield Accelerator test facility and observed wakefields excited by a single high charge electron bunch when it passes through a PBG accelerator structure. Excellent HOM suppression properties of the PBG accelerator were demonstrated in the beam test.

  2. Observation of Wakefield Suppression in a Photonic-Band-Gap Accelerator Structure

    DOE PAGES

    Simakov, Evgenya I.; Arsenyev, Sergey A.; Buechler, Cynthia E.; ...

    2016-02-10

    We report experimental observation of higher order mode (HOM) wakefield suppression in a room-temperature traveling-wave photonic band gap (PBG) accelerating structure at 11.700 GHz. It has been long recognized that PBG structures have potential for reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in a room-temperature PBG structure was conducted in 2005. Since then, the importance of PBG accelerator research has been recognized by many institutions. However, the full experimental characterization of the wakefield spectrum and demonstration of wakefield suppression when the accelerating structure is excited by an electron beam has not been performed to date. Wemore » conducted an experiment at the Argonne Wakefield Accelerator (AWA) test facility and observed wakefields excited by a single high charge electron bunch when it passes through a PBG accelerator structure. Lastly, excellent HOM suppression properties of the PBG accelerator were demonstrated in the beam test.« less

  3. Observation of Wakefield Suppression in a Photonic-Band-Gap Accelerator Structure

    SciTech Connect

    Simakov, Evgenya I.; Arsenyev, Sergey A.; Buechler, Cynthia E.; Edwards, Randall L.; Romero, William P.; Conde, Manoel; Ha, Gwanghui; Power, John G.; Wisniewski, Eric E.; Jing, Chunguang

    2016-02-10

    We report experimental observation of higher order mode (HOM) wakefield suppression in a room-temperature traveling-wave photonic band gap (PBG) accelerating structure at 11.700 GHz. It has been long recognized that PBG structures have potential for reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in a room-temperature PBG structure was conducted in 2005. Since then, the importance of PBG accelerator research has been recognized by many institutions. However, the full experimental characterization of the wakefield spectrum and demonstration of wakefield suppression when the accelerating structure is excited by an electron beam has not been performed to date. We conducted an experiment at the Argonne Wakefield Accelerator (AWA) test facility and observed wakefields excited by a single high charge electron bunch when it passes through a PBG accelerator structure. Lastly, excellent HOM suppression properties of the PBG accelerator were demonstrated in the beam test.

  4. Diamond field emitter array cathodes and possibilities of employing additive manufacturing for dielectric laser accelerating structures

    NASA Astrophysics Data System (ADS)

    Simakov, Evgenya I.; Andrews, Heather L.; Herman, Matthew J.; Hubbard, Kevin M.; Weis, Eric

    2017-03-01

    Demonstration of a stand-alone practical dielectric laser accelerator (DLA) requires innovation in two major critical components: high-current ultra-low-emittance cathodes and efficient laser accelerator structures. LANL develops two technologies that in our opinion are applicable to the novel DLA architectures: diamond field emitter array (DFEA) cathodes and additive manufacturing of photonic band-gap (PBG) structures. This paper discusses the results of testing of DFEA cathodes in the field-emission regime and the possibilities for their operation in the photoemission regime, and compares their emission characteristics to the specific needs of DLAs. We also describe recent advances in additive manufacturing of dielectric woodpile structures using a Nanoscribe direct laser-writing device capable of maskless lithography and additive manufacturing, and the development of novel infrared dielectric materials compatible with additive manufacturing.

  5. Accelerating clinical insights: how to use accelerator mass spectrometry to make better early development decisions.

    PubMed

    Seymour, Mark

    2010-12-01

    This paper is an overview of the applications of the technique of Accelerator Mass Spectrometry (AMS) in the biomedical drug development field. The work described here has been carried out at Xceleron (York, UK and Germantown, MD, USA), and it aims to apply AMS to provide better information about the human pharmacokinetic/metabolic behaviour of drugs or drug candidates as early as possible. It is hoped that the use of this technique will contribute to the delivery of better, more effective drugs onto the market sooner, which will be good news for all concerned.

  6. A two-fluid model for black-hole accretion flows: particle acceleration and disc structure

    NASA Astrophysics Data System (ADS)

    Lee, Jason P.; Becker, Peter A.

    2017-02-01

    Hot, tenuous advection-dominated accretion flows around black holes are ideal sites for the Fermi acceleration of relativistic particles at standing shock waves in the accretion disc. Previous work has demonstrated that the shock-acceleration process can be efficient enough to power the observed, strong outflows in radio-loud active galaxies such as M87. However, the dynamical effect (back-reaction) on the flow, exerted by the pressure of the relativistic particles, has not been previously considered, and this effect can have a significant influence on the disc structure. We reexamine the problem by developing a new, two-fluid model for the structure of the accretion disc that includes the dynamical effect of the relativistic particle pressure, combined with the pressure of the background (thermal) gas. The new model is analogous to the two-fluid model of cosmic ray acceleration in supernova-driven shock waves. As part of the model, we also develop a new set of shock jump conditions, which are solved along with the hydrodynamic conservation equations to determine the structure of the accretion disc. The solutions include the formation of a mildly relativistic outflow (jet) at the shock radius, driven by the relativistic particles accelerated in the disc. One of our main conclusions is that in the context of the new two-fluid accretion model, global smooth (shock-free) solutions do not exist, and the disc must always contain a standing shock wave, at least in the inviscid case considered here.

  7. Accelerating Vaccine Formulation Development Using Design of Experiment Stability Studies.

    PubMed

    Ahl, Patrick L; Mensch, Christopher; Hu, Binghua; Pixley, Heidi; Zhang, Lan; Dieter, Lance; Russell, Ryann; Smith, William J; Przysiecki, Craig; Kosinski, Mike; Blue, Jeffrey T

    2016-10-01

    Vaccine drug product thermal stability often depends on formulation input factors and how they interact. Scientific understanding and professional experience typically allows vaccine formulators to accurately predict the thermal stability output based on formulation input factors such as pH, ionic strength, and excipients. Thermal stability predictions, however, are not enough for regulators. Stability claims must be supported by experimental data. The Quality by Design approach of Design of Experiment (DoE) is well suited to describe formulation outputs such as thermal stability in terms of formulation input factors. A DoE approach particularly at elevated temperatures that induce accelerated degradation can provide empirical understanding of how vaccine formulation input factors and interactions affect vaccine stability output performance. This is possible even when clear scientific understanding of particular formulation stability mechanisms are lacking. A DoE approach was used in an accelerated 37(°)C stability study of an aluminum adjuvant Neisseria meningitidis serogroup B vaccine. Formulation stability differences were identified after only 15 days into the study. We believe this study demonstrates the power of combining DoE methodology with accelerated stress stability studies to accelerate and improve vaccine formulation development programs particularly during the preformulation stage.

  8. 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.

  9. Impact of accelerated plant growth on seed variety development

    NASA Astrophysics Data System (ADS)

    Christophersen, Eric

    1998-01-01

    The commercial lives of agricultural seed products have steadily declined in recent years. The introduction of genetically engineered crop seeds in 1966 has accentuated that trend. Widespread grower demand for genetically engineered seed requires competitive response by industry followers in order to avert market share losses to the industry leaders. Limitations on plant transformation technology, regulatory requirements and patent impediments require companies to rapidly convert transformed lines into elite commercial products. Massive multigenerational backcrossing efforts are required to distribute genetically engineered traits into a broad product mix. Significant incidents of expression failures, or ``gene silencing,'' have occurred unexpectedly, requiring product substitution strategies. First-to-market strategies, competitive response, broad germplasm conversion and rescue of product failures all share the element of urgency. Technologies which reliably accelerate product development rates can expect favorable reception by commercial seed developers. A growth chamber which dramatically accelerates the rate of plant growth is described.

  10. Rail accelerator development for ultra-high pressure research

    SciTech Connect

    Hawke, R.S.; Nellis, W.J.; Rego, J.; Susoeff, A.R.; Newman, G.H.

    1983-09-20

    The Lawrence Livermore National Laboratory is currently developing a rail accelerator system for launching hypervelocity projectiles suitable for ultrahigh pressure shockwave research. The primary goal is to accelerate 1 g projectiles with disk impactors to velocities in excess of 12 km/s and generate uniform, planar shockwaves at pressures above 0.5 TPa (5 Mbar) in metal targets. In order to generate precisely controlled impacts and shockwaves, several strigent requirements are imposed on the railgun system. During the last year, we have begun detailed development of a railgun launcher and power source. We are developing a launcher with a gas injector. The injector accelerates the projectile to more than 1 km/s reducing the dwell time of the plasma arc and the erosion of the rails. The injected projectile, with a fuse, also serves as the main switch in the power supply circuit. Current pulse shaping is used to control the applied stress to the projectile and launcher. Results of experiments with the new system will be reported and compared to computer simulations.

  11. Rail accelerator development for ultra-high pressure research

    SciTech Connect

    Hawke, R.S.; Nellis, W.J.

    1984-03-01

    The Lawrence Livermore National Laboratory is currently developing a rail accelerator system for launching hypervelocity projectiles suitable for ultrahigh pressure shockwave research. The primary goal is to accelerate 1 g projectiles with disk impactors to velocities in excess of 12 km/s and generate uniform, planar shockwaves at pressures above 0.5 TPa (5 Mbar) in metal targets. In order to generate precisely controlled impacts and shockwaves, several stringent requirements are imposed on the railgun system. During the last year, detailed development of a railgun launcher and power source has begun. A launcher with a gas injector is being developed. The injector accelerates the projectile to more than 1 km/s reducing the dwell time of the plasma arc and the erosion of the rails. The injected projectile, with a fuse, also serves as the main switch in the power supply circuit. Current pulse shaping is used to control the applied stress to the projectile and launcher. Results of experiments with the new system are reported and compared to computer simulations.

  12. Accelerated molecular dynamics methods: introduction and recent developments

    SciTech Connect

    Uberuaga, Blas Pedro; Voter, Arthur F; Perez, Danny; Shim, Y; Amar, J G

    2009-01-01

    A long-standing limitation in the use of molecular dynamics (MD) simulation is that it can only be applied directly to processes that take place on very short timescales: nanoseconds if empirical potentials are employed, or picoseconds if we rely on electronic structure methods. Many processes of interest in chemistry, biochemistry, and materials science require study over microseconds and beyond, due either to the natural timescale for the evolution or to the duration of the experiment of interest. Ignoring the case of liquids xxx, the dynamics on these time scales is typically characterized by infrequent-event transitions, from state to state, usually involving an energy barrier. There is a long and venerable tradition in chemistry of using transition state theory (TST) [10, 19, 23] to directly compute rate constants for these kinds of activated processes. If needed dynamical corrections to the TST rate, and even quantum corrections, can be computed to achieve an accuracy suitable for the problem at hand. These rate constants then allow them to understand the system behavior on longer time scales than we can directly reach with MD. For complex systems with many reaction paths, the TST rates can be fed into a stochastic simulation procedure such as kinetic Monte Carlo xxx, and a direct simulation of the advance of the system through its possible states can be obtained in a probabilistically exact way. A problem that has become more evident in recent years, however, is that for many systems of interest there is a complexity that makes it difficult, if not impossible, to determine all the relevant reaction paths to which TST should be applied. This is a serious issue, as omitted transition pathways can have uncontrollable consequences on the simulated long-time kinetics. Over the last decade or so, we have been developing a new class of methods for treating the long-time dynamics in these complex, infrequent-event systems. Rather than trying to guess in advance what

  13. Design of a 30 GHz Damped Detuned Accelerating Structure

    NASA Astrophysics Data System (ADS)

    Dehler, M.; Wilson, I.; Wuensch, W.; Jones, R. M.; Kroll, N. M.; Miller, R. H.

    1997-05-01

    Within the framework of the SLAC/CERN studies of 30 GHz linear colliders, an attempt has been made to scale the existing X-band NLC damped detuned accelerating structure to 30 GHz. A simple scaling was not chosen because of anticipated manufacturing difficulties. The new manifold-damped design has 101 cells and a minimum aperture of 3.4 mm. In order to obtain acceptably small values for both the single-bunch transverse wakefield and the long-range multibunch wakefield a relatively large non-linear variation of the iris thickness was introduced in addition to the iris diameter variation. The resulting short-range wakefield is 1270 V/pC/mm/m decreasing to less than 1after 1 ns.

  14. Space station structures development

    NASA Technical Reports Server (NTRS)

    Teller, V. B.

    1986-01-01

    A study of three interrelated tasks focusing on deployable Space Station truss structures is discussed. Task 1, the development of an alternate deployment system for linear truss, resulted in the preliminary design of an in-space reloadable linear motor deployer. Task 2, advanced composites deployable truss development, resulted in the testing and evaluation of composite materials for struts used in a deployable linear truss. Task 3, assembly of structures in space/erectable structures, resulted in the preliminary design of Space Station pressurized module support structures. An independent, redundant support system was developed for the common United States modules.

  15. New Developments in the Simulation of Advanced Accelerator Concepts

    SciTech Connect

    Bruhwiler, David L.; Cary, John R.; Cowan, Benjamin M.; Paul, Kevin; Mullowney, Paul J.; Messmer, Peter; Geddes, Cameron G. R.; Esarey, Eric; Cormier-Michel, Estelle; Leemans, Wim; Vay, Jean-Luc

    2009-01-22

    Improved computational methods are essential to the diverse and rapidly developing field of advanced accelerator concepts. We present an overview of some computational algorithms for laser-plasma concepts and high-brightness photocathode electron sources. In particular, we discuss algorithms for reduced laser-plasma models that can be orders of magnitude faster than their higher-fidelity counterparts, as well as important on-going efforts to include relevant additional physics that has been previously neglected. As an example of the former, we present 2D laser wakefield accelerator simulations in an optimal Lorentz frame, demonstrating >10 GeV energy gain of externally injected electrons over a 2 m interaction length, showing good agreement with predictions from scaled simulations and theory, with a speedup factor of {approx}2,000 as compared to standard particle-in-cell.

  16. New Developments in the Simulation of Advanced Accelerator Concepts

    SciTech Connect

    Paul, K.; Cary, J.R.; Cowan, B.; Bruhwiler, D.L.; Geddes, C.G.R.; Mullowney, P.J.; Messmer, P.; Esarey, E.; Cormier-Michel, E.; Leemans, W.P.; Vay, J.-L.

    2008-09-10

    Improved computational methods are essential to the diverse and rapidly developing field of advanced accelerator concepts. We present an overview of some computational algorithms for laser-plasma concepts and high-brightness photocathode electron sources. In particular, we discuss algorithms for reduced laser-plasma models that can be orders of magnitude faster than their higher-fidelity counterparts, as well as important on-going efforts to include relevant additional physics that has been previously neglected. As an example of the former, we present 2D laser wakefield accelerator simulations in an optimal Lorentz frame, demonstrating>10 GeV energy gain of externally injected electrons over a 2 m interaction length, showing good agreement with predictions from scaled simulations and theory, with a speedup factor of ~;;2,000 as compared to standard particle-in-cell.

  17. Deamidation accelerates amyloid formation and alters amylin fiber structure

    PubMed Central

    Dunkelberger, Emily B.; Buchanan, Lauren E.; Marek, Peter; Cao, Ping; Raleigh, Daniel P.; Zanni, Martin T.

    2012-01-01

    Deamidation of asparagine and glutamine is the most common non-enzymatic, post-translational modification. Deamidation can influence the structure, stability, folding, and aggregation of proteins and has been proposed to play a role in amyloid formation. However there are no structural studies of the consequences of deamidation on amyloid fibers, in large part because of the difficulty of studying these materials using conventional methods. Here we examine the effects of deamidation on the kinetics of amyloid formation by amylin, the causative agent of type 2 diabetes. We find that deamidation accelerates amyloid formation and the deamidated material is able to seed amyloid formation by unmodified amylin. Using site-specific isotope labeling and two-dimensional infrared (2D IR) spectroscopy, we show that fibers formed by samples that contain deamidated polypeptide contain reduced amounts of β-sheet. Deamidation leads to disruption of the N-terminal β-sheet between Ala-8 and Ala-13, but β-sheet is still retained near Leu-16. The C-terminal sheet is disrupted near Leu-27. Analysis of potential sites of deamidation together with structural models of amylin fibers reveals that deamidation in the N-terminal β-sheet region may be the cause for the disruption of the fiber structure at both the N- and C-terminal β-sheet. Thus, deamidation is a post-translational modification that creates fibers which have an altered structure, but can still act as a template for amylin aggregation. Deamidation is very difficult to detect with standard methods used to follow amyloid formation, but isotope labeled IR spectroscopy provides a means for monitoring sample degradation and investigating the structural consequences of deamidation. PMID:22734583

  18. Design, development, and acceleration trials of radio-frequency quadrupole

    SciTech Connect

    Rao, S. V. L. S. Jain, Piyush; Pande, Rajni; Roy, Shweta; Mathew, Jose V.; Kumar, Rajesh; Pande, Manjiri; Krishnagopal, S.; Gupta, S. K.; Singh, P.

    2014-04-15

    A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 μm leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (∼±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D{sup +}) beam, we tested it by accelerating both the proton (H{sup +}) and D{sup +} beams. The RFQ was operated in pulsed mode and accelerated both H{sup +} and D{sup +} beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.

  19. Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime

    SciTech Connect

    Higo, Toshiyasu; Higashi, Yasuo; Matsumoto, Shuji; Yokoyama, Kazue; Adolphsen, Chris; Dolgashev, Valery; Jensen, Aaron; Laurent, Lisa; Tantawi, Sami; Wang, Faya; Wang, Juwen; Dobert, Steffen; Grudiev, Alexej; Riddone, Germana; Wuensch, Walter; Zennaro, Riccardo; /CERN

    2012-07-05

    A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One of the goals has been to refine the essential parameters and fabrication procedures needed to realize such a high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that the surface temperature rise during the pulse be higher, which may increase the breakdown rate. One structure with heavy damping has been RF processed and another is nearly finished. The breakdown rates of these structures were found to be higher by two orders of magnitude compared to those with equivalent acceleration mode parameters but without the damping features. This paper presents these results together with some of the earlier results from non-damped structures.

  20. Rail-accelerator development for ultra-high-pressure research

    SciTech Connect

    Hawke, R.S.; Nellis, W.J.; Rego, J.; Susoeff, A.R.; Newman, G.H.

    1983-09-14

    During the last year, we have begun detailed development of a railgun launcher and power source. We are developing a launcher with a gas injector. The injector accelerates the projectile to more than 1 km/s reducing the dwell time of the plasma arc and the erosion of the rails. The injected projectile, with a fuse, also serves as the main switch in the power supply circuit. Current pulse shaping is used to control the applied stress to the projectile and launcher. Results of experiments with the new system will be reported and compared to computer simulations.

  1. [Acceleration of Embryonic Development of Pinus sibirica Trees with a One-Year Reproductive Cycle].

    PubMed

    Tret'yakova, I N; Lukina, N V

    2016-01-01

    The study of the formation of embryonic structures in Pinus sibirica forms with a one-year reproductive cycle showed that the acceleration of the embryonic process manifested itself as a reduction of the coenocytic stage of the female gametophyte development (1.5 months instead of 1 year). The egg was not fertilized because of the asynchronous maturation of male and female gametophytes. Seeds without embryos were formed. We assumed that the acceleration of the reproductive process in Pinus sibirica was caused by a mutation in the female generative organs.

  2. Development of the brine shrimp Artemia is accelerated during spaceflight

    NASA Technical Reports Server (NTRS)

    Spooner, B. S.; Metcalf, J.; DeBell, L.; Paulsen, A.; Noren, W.; Guikema, J. A.

    1994-01-01

    Developmentally arrested brine shrimp cysts have been reactivated during orbital spaceflight on two different Space Shuttle missions (STS-50 and STS-54), and their subsequent development has been compared with that of simultaneously reactivated ground controls. Flight and control brine shrimp do not significantly differ with respect to hatching rates or larval morphology at the scanning and transmission EM levels. A small percentage of the flight larvae had defective nauplier eye development, but the observation was not statistically significant. However, in three different experiments on two different flights, involving a total of 232 larvae that developed in space, a highly significant difference in degree of flight to control development was found. By as early as 2.25 days after reactivation of development, spaceflight brine shrimp were accelerated, by a full instar, over ground control brine shrimp. Although developing more rapidly, flight shrimp grew as long as control shrimp at each developmental instar or stage.

  3. Development of the brine shrimp Artemia is accelerated during spaceflight.

    PubMed

    Spooner, B S; Metcalf, J; DeBell, L; Paulsen, A; Noren, W; Guikema, J A

    1994-07-01

    Developmentally arrested brine shrimp cysts have been reactivated during orbital spaceflight on two different Space Shuttle missions (STS-50 and STS-54), and their subsequent development has been compared with that of simultaneously reactivated ground controls. Flight and control brine shrimp do not significantly differ with respect to hatching rates or larval morphology at the scanning and transmission EM levels. A small percentage of the flight larvae had defective nauplier eye development, but the observation was not statistically significant. However, in three different experiments on two different flights, involving a total of 232 larvae that developed in space, a highly significant difference in degree of flight to control development was found. By as early as 2.25 days after reactivation of development, spaceflight brine shrimp were accelerated, by a full instar, over ground control brine shrimp. Although developing more rapidly, flight shrimp grew as long as control shrimp at each developmental instar or stage.

  4. Spatial structure of the neck and acceleration processes in a micropinch

    NASA Astrophysics Data System (ADS)

    Dolgov, A. N.; Klyachin, N. A.; Prokhorovich, D. E.

    2016-12-01

    It is shown that the spatial structure of the micropinch neck during the transition from magnetohydrodynamic to radiative compression and the bremsstrahlung spectrum of the discharge in the photon energy range of up to 30 keV depend on the configuration of the inner electrode of the coaxial electrode system of the micropinch discharge. Analysis of the experimental results indicates that the acceleration processes in the electron component of the micropinch plasma develop earlier than radiative compression.

  5. Dynamic behavior of time-delayed acceleration feedback controller for active vibration control of flexible structures

    NASA Astrophysics Data System (ADS)

    An, Fang; Chen, Wei-dong; Shao, Min-qiang

    2014-09-01

    This paper addresses the design problem of the controller with time-delayed acceleration feedback. On the basis of the reduction method and output state-derivative feedback, a time-delayed acceleration feedback controller is proposed. Stability boundaries of the closed-loop system are determined by using Hurwitz stability criteria. Due to the introduction of time delay into the controller with acceleration feedback, the proposed controller has the feature of not only changing the mass property but also altering the damping property of the controlled system in the sense of equivalent structural modification. With this feature, the closed-loop system has a greater logarithmic decrement than the uncontrolled one, and in turn, the control behavior can be improved. In this connection, the time delay in the acceleration feedback control is a positive factor when satisfying some given conditions and it could be actively utilized. On the ground of the analysis, the developed controller is implemented on a cantilever beam for different controller gain-delay combinations, and the control performance is evaluated with the comparison to that of pure acceleration feedback controller. Simulation and experimental results verify the ability of the controller to attenuate the vibration resulting from the dominant mode.

  6. Development of an accelerating-piston implosion-driven launcher

    NASA Astrophysics Data System (ADS)

    Huneault, Justin; Loiseau, Jason; Higgins, Andrew

    2013-06-01

    The ability to soft-launch projectiles at velocities exceeding 10 km/s is of interest to several scientific fields, including orbital debris impact testing and equation of state research. Current soft-launch technologies have reached a performance plateau below this operating range. The energy and power density of high explosives provides a possible avenue to reach this velocity if used to dynamically compress a light driver gas to significantly higher pressures and temperatures compared to light-gas guns. In the implosion-driven launcher (IDL), linear implosion of a pressurized tube drives a strong shock into the gas ahead of the tube pinch, thereby forming an increasingly long column of compressed gas which can be used to propel a projectile. The McGill IDL has demonstrated the ability to launch a 0.1-g projectile to 9.1 km/s. This study focuses on the implementation of a novel launch cycle wherein the explosively driven pinch is accelerated down the length of the tube in order to maintain a relatively constant projectile base pressure early in the launch cycle. The experimental development of an accelerating driver which utilizes an explosive lens to phase the detonation wave is presented. The design and experimental performance of an accelerating-piston IDL is also discussed.

  7. Development of a sealed-accelerator-tube neutron generator

    PubMed

    Verbeke; Leung; Vujic

    2000-10-01

    Sealed-accelerator-tube neutron generators are being developed in Lawrence Berkeley National Laboratory (LBNL) for applications ranging from neutron radiography to boron neutron capture therapy and neutron activation analysis. The new generation of high-output neutron generators is based on the D-T fusion reaction, producing 14.1-MeV neutrons. The main components of the neutron tube--the ion source, the accelerator and the target--are all housed in a sealed metal container without external pumping. Thick-target neutron yield computations are performed in this paper to estimate the neutron yield of titanium and scandium targets. With an average deuteron beam current of 1 A and an energy of 120 keV, a time-averaged neutron production of approximately 10(14) n/s can be estimated for a tritiated target, for both pulsed and cw operations. In mixed deuteron/triton beam operation, a beam current of 2 A at 150 keV is required for the same neutron output. Recent experimental results on ion sources and accelerator columns are presented and discussed.

  8. Space Structure Development

    NASA Technical Reports Server (NTRS)

    Smith, Thomas

    2015-01-01

    The duration of my Summer 2015 Internship Tour at NASA's Johnson Space Center was spent working in the Structural Engineering Division's Structures Branch. One of the two main roles of the Structures Branch, ES2, is to ensure the structural integrity of spacecraft vehicles and the structural subsystems needed to support those vehicles. The other main objective of this branch is to develop the lightweight structures that are necessary to take humans beyond Low-Earth Orbit. Within ES2, my four projects involved inflatable space structure air bladder material testing; thermal and impact material testing for spacecraft windows; structural analysis on a joint used in the Boeing CST-100 airbag system; and an additive manufacturing design project.

  9. Superconducting Accelerating Structure for High-Current Cyclotrons for Accelerator-Driven Subcritical Fission

    NASA Astrophysics Data System (ADS)

    Pogue, Nathaniel; McIntyre, Peter; Sattarov, Akhdiyor

    2011-10-01

    An accelerator driven molten salt fission core is being designed to provide reliable power by subcritical nuclear fission for the next few millennia. Fission is driven by proton beams from a flux-coupled stack of three high-current cyclotrons. A key innovation in attaining the needed beam current and efficiency is a superconducting Niobium rf accelerating cavity that can accelerate bunches in the 200 orbits uniformly. The unique design allows for several cavities to be stacked, and also provides uniform acceleration and eliminates higher order modes in the cyclotron. The design and properties of the superconducting cavity will increase the efficiency of the cyclotron and the overall energy amplification from the molten salt core by an order of magnitude compared to conventional designs.

  10. Plasma Accelerator Development for Dynamic Formation of Plasma Liners: A Status Report

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Eskridge, Richard; Martin, Adam; Smith, James; Lee, Michael; Rodgers, Stephen L. (Technical Monitor)

    2001-01-01

    An experimental plasma accelerator for magnetic target fusion (MTF) applications under development at the NASA Marshall Space Flight Center is described. The accelerator is a pulsed plasma thruster and has been tested experimentally and plasma jet velocities of approximately 50 km/sec have been obtained. The plasma jet structure has been photographed with 10 ns exposure times to reveal a stable and repeatable plasma structure. Data for velocity profile information has been obtained using light pipes embedded in the gun walls to record the plasma transit at various barrel locations. Preliminary spatially resolved spectral data and magnetic field probe data are also presented. A high speed triggering system has been developed and tested as a means of reducing the gun "jitter". This jitter is being characterized and future work for second generation "ultra-low jitter" gun development is being identified.

  11. Laser Wakefield Acceleration: Structural and Dynamic Studies. Final Technical Report ER40954

    SciTech Connect

    Downer, Michael C.

    2014-04-30

    -15 seconds) in duration and 150 Joules in energy (equivalent to the muzzle energy of a small pistol bullet). This duration was well matched to the natural electron density oscillation period of plasma of 1/100 atmospheric density, enabling efficient excitation of a plasma wake, while this energy was sufficient to drive a high-amplitude wake of the right shape to produce an energetic, collimated electron beam. Continuing research is aimed at increasing electron energy even further, increasing the number of electrons captured and accelerated, and developing applications of the compact, multi-GeV accelerator as a coherent, hard x-ray source for materials science, biomedical imaging and homeland security applications. The second major advance under this project was to develop new methods of visualizing the laser-driven plasma wake structures that underlie laser-plasma accelerators. Visualizing these structures is essential to understanding, optimizing and scaling laser-plasma accelerators. Yet prior to work under this project, computer simulations based on estimated initial conditions were the sole source of detailed knowledge of the complex, evolving internal structure of laser-driven plasma wakes. In this project we developed and demonstrated a suite of optical visualization methods based on well-known methods such as holography, streak cameras, and coherence tomography, but adapted to the ultrafast, light-speed, microscopic world of laser-driven plasma wakes. Our methods output images of laser-driven plasma structures in a single laser shot. We first reported snapshots of low-amplitude laser wakes in Nature Physics in 2006. We subsequently reported images of high-amplitude laser-driven plasma “bubbles”, which are important for producing electron beams with low energy spread, in Physical Review Letters in 2010. More recently, we have figured out how to image laser-driven structures that change shape while propagating in a single laser shot. The latter techniques, which use

  12. Latest Diagnostic Electronics Development for the PROSCAN Proton Accelerator

    SciTech Connect

    Duperrex, P.A.; Frei, U.; Gamma, G.; Mueller, U.; Rezzonico, L.

    2004-11-10

    New VME-based diagnostic electronics are being developed for PROSCAN, a proton accelerator for medical application presently under construction at PSI. One new development is a VME-based multi-channel logarithmic amplifier for converting current to voltage (LogIV). The LogIV boards are used for measuring current from the multiple wire (harp) profile monitors. The LogIV calibration method, current dependant bandwidth and temperature stability are presented. Another development is a BPM front end, based on the newest digital receiver techniques. Features of this new system are the remote control of the preamplifier stage and the continuous monitoring of each individual signal overall gain. Characteristics of the developed prototype are given.

  13. Parallel Computation of Integrated Electromagnetic, Thermal and Structural Effects for Accelerator Cavities

    SciTech Connect

    Akcelik, V.; Candel, A.E.; Kabel, A.C.; Ko, K.; Lee, L.; Li, Z.; Ng, C.K.; Xiao, L.; /SLAC

    2011-11-02

    The successful operation of accelerator cavities has to satisfy both rf and mechanical requirements. It is highly desirable that electromagnetic, thermal and structural effects such as cavity wall heating and Lorentz force detuning in superconducting rf cavities can be addressed in an integrated analysis. Based on the SLAC parallel finite-element code infrastructure for electromagnetic modeling, a novel multi-physics analysis tool has been developed to include additional thermal and mechanical effects. The parallel computation enables virtual prototyping of accelerator cavities on computers, which would substantially reduce the cost and time of a design cycle. The multi-physics tool is applied to the LCLS rf gun for electromagnetic, thermal and structural analyses.

  14. Acceleration response spectrum for prediction of structural vibration due to individual bouncing

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Wang, Lei; Racic, Vitomir; Lou, Jiayue

    2016-08-01

    This study is designed to develop an acceleration response spectrum that can be used in vibration serviceability assessment of civil engineering structures, such as floors and grandstands those are dynamically excited by individual bouncing. The spectrum is derived from numerical simulations and statistical analysis of acceleration responses of a single degree of freedom system with variable natural frequency and damping under a large number of experimentally measured individual bouncing loads. Its mathematical representation is fit for fast yet reliable application in design practice and is comprised of three equations that describe three distinct frequency regions observed in the actual data: the first resonant plateau (2-3.5 Hz), the second resonant plateau (4-7 Hz) and a descension region (7-15 Hz). Finally, this paper verifies the proposed response spectrum approach to predict structural vibration by direct comparison against numerical simulations and experimental results.

  15. Structure-Based Drug Discovery Accelerated by Many-Core Devices.

    PubMed

    Feinstein, Wei; Brylinski, Michal

    2016-01-01

    Computer-aided design is one of the critical components of modern drug discovery. Drug development is routinely streamlined using computational approaches to improve hit identification and lead selection, enhance bioavailability, and reduce toxicity. A mounting body of genomic knowledge accumulated during the last decade or so presents great opportunities for pharmaceutical research. However, new challenges also arose because processing this large volume of data demands unprecedented computing resources. On the other hand, the state-of-the-art heterogeneous systems deliver petaflops of peak performance to accelerate scientific discovery. In this communication, we review modern parallel accelerator architectures, mainly focusing on Intel Xeon Phi many-core devices. Xeon Phi is a relatively new platform that features tens of computing cores with hundreds of threads offering massively parallel capabilities for a broad range of application. We also discuss common parallel programming frameworks targeted to this accelerator, including OpenMP, OpenCL, MPI and HPX. Recent advances in code development for many-core devices are described to demonstrate the advantages of heterogeneous implementations over the traditional, serial computing. Finally, we highlight selected algorithms, eFindSite, a ligand binding site predictor, a force field for bio-molecular simulations, and BUDE, a structure-based virtual screening engine, to demonstrate how modern drug discovery is accelerated by heterogeneous systems equipped with parallel computing devices.

  16. Enhancing Target Normal Sheath Accelerated Ions with Micro-structured Targets

    NASA Astrophysics Data System (ADS)

    George, Kevin; Snyder, Joseph; Ji, Liangliang; Rubin, Trevor; Handler, Abraham; Poole, Patrick; Willis, Christopher; Daskalova, Rebecca; Cochran, Ginevra; Schumacher, Douglass

    2016-10-01

    Laser driven target normal sheath acceleration (TNSA) of ions has been widely studied due to its fundamental importance, use as a probe, and for possible applications such as cancer therapy and neutron generation. Much of this work has been conducted on thin foils with peak ion energy and yield optimized using laser parameters such as energy and spot size. Micro-structured targets, however, have demonstrated increased peak ion energy and yield by controlling and enhancing mechanisms preferential to TNSA. Novel micro-structured targets were developed using optical lithography techniques on thin substrates at the OSU NanoSystem Laboratory. Variable structure height (0.5-2 micron) and transverse patterning (up to 1 micron resolution) permit the survey of a range of structured target variables in the study of ion acceleration. We describe the development of these targets and an experiment investigating the enhancement of TNSA ions from lithography produced micro-structured targets conducted at the Scarlet Laser Facility. Experimental results show increased proton and Carbon yield >2 MeV and higher peak Carbon energy from structured targets. This work was supported by the Air Force Office of Scientific Research.

  17. Development of the SCRF Power Coupler for the APT Accelerator

    SciTech Connect

    Schmierer, E.N.; Lujan, R.E.; Rusnak, B.; Smith, B.; Haynes, W.B.; Gautier, C.; Waynert, J.A.; Krawczyk, F.; Gioia, J.

    1999-03-01

    The team responsible for the design of the Accelerator Production of Tritium (APT) superconducting (SC) radio frequency (RF) power coupler has developed two 700-MHz, helium gas-cooled power couplers. One has a fixed inner conductor and the other has an adjustable inner conductor (gamma prototype and alpha prototype). The power couplers will be performance tested in the near future. This paper discusses the mechanical design and fabrication techniques employed in the development of each power coupler. This includes material selection, copper coating, assembly sequences, and metal joining procedures, as well as the engineering analyses performed to determine the dynamic response of the inner conductors due to environmental excitations. A bellows is used in both prototype inner conductors in the area near the ceramic RF window, to compensate for thermal expansion and mechanical tolerance build-up. In addition, a bellows is used near the tip of the inner conductor of the alpha prototype for running the power coupler after it is installed on the accelerator. Extensive analytical work has been performed to determine the static loads transmitted by the bellows due to thermally induced expansion on the inner conductor and on the RF window. This paper also discusses this analysis, as well as the mechanical analysis performed to determine the final geometric shape of the bellows. Finally, a discussion of the electromagnetic analysis used to optimize the performance of the power couplers is included.

  18. Accelerate!

    PubMed

    Kotter, John P

    2012-11-01

    The old ways of setting and implementing strategy are failing us, writes the author of Leading Change, in part because we can no longer keep up with the pace of change. Organizational leaders are torn between trying to stay ahead of increasingly fierce competition and needing to deliver this year's results. Although traditional hierarchies and managerial processes--the components of a company's "operating system"--can meet the daily demands of running an enterprise, they are rarely equipped to identify important hazards quickly, formulate creative strategic initiatives nimbly, and implement them speedily. The solution Kotter offers is a second system--an agile, networklike structure--that operates in concert with the first to create a dual operating system. In such a system the hierarchy can hand off the pursuit of big strategic initiatives to the strategy network, freeing itself to focus on incremental changes to improve efficiency. The network is populated by employees from all levels of the organization, giving it organizational knowledge, relationships, credibility, and influence. It can Liberate information from silos with ease. It has a dynamic structure free of bureaucratic layers, permitting a level of individualism, creativity, and innovation beyond the reach of any hierarchy. The network's core is a guiding coalition that represents each level and department in the hierarchy, with a broad range of skills. Its drivers are members of a "volunteer army" who are energized by and committed to the coalition's vividly formulated, high-stakes vision and strategy. Kotter has helped eight organizations, public and private, build dual operating systems over the past three years. He predicts that such systems will lead to long-term success in the 21st century--for shareholders, customers, employees, and companies themselves.

  19. A strategic plan to accelerate development of acute stroke treatments.

    PubMed

    Marler, John R

    2012-09-01

    In order to reenergize acute stroke research and accelerate the development of new treatments, we need to transform the usual design and conduct of clinical trials to test for small but significant improvements in effectiveness, and treat patients as soon as possible after stroke onset when treatment effects are most detectable. This requires trials that include thousands of acute stroke patients. A plan to make these trials possible is proposed. There are four components: (1) free access to the electronic medical record; (2) a large stroke emergency network and clinical trial coordinating center connected in real time to hundreds of emergency departments; (3) a clinical trial technology development center; and (4) strategic leadership to raise funds, motivate clinicians to participate, and interact with politicians, insurers, legislators, and other national and international organizations working to advance the quality of stroke care.

  20. Improving and Accelerating Drug Development for Nervous System Disorders

    PubMed Central

    Pankevich, Diana E.; Altevogt, Bruce M.; Dunlop, John; Gage, Fred H.; Hyman, Steve E.

    2014-01-01

    Advances in the neurosciences have placed the field in the position where it is poised to significantly reduce the burden of nervous system disorders. However, drug discovery, development and translation for nervous system disorders still pose many unique challenges. The key scientific challenges can be summarized as follows: mechanisms of disease, target identification and validation, predictive models, biomarkers for patient stratification and as endpoints for clinical trials, clear regulatory pathways, reliability and reproducibility of published data, and data sharing and collaboration. To accelerate nervous system drug development the Institute of Medicine’s Forum on Neuroscience and Nervous System Disorders has hosted a series of public workshops that brought together representatives of industry, government (including both research funding and regulatory agencies), academia, and patient groups to discuss these challenges and offer potential strategies to improve the translational neuroscience. PMID:25442933

  1. Electron acceleration by an electromagnetic wave propagating across a magnetic field in periodic structures

    NASA Astrophysics Data System (ADS)

    Buts, V. A.; Ognivenko, V. V.

    1990-05-01

    The possibility of the acceleration of charged particles captured by an electromagnetic wave propagating across a constant magnetic field in periodic slow-wave structures is demonstrated. A plane waveguide with perfectly conducting walls is examined as an example of an electrodynamic structure in which such an acceleration mechanism is possible. The acceleration rate is determined, and the stability of captured particle motion is investigated.

  2. Highly Productive Application Development with ViennaCL for Accelerators

    NASA Astrophysics Data System (ADS)

    Rupp, K.; Weinbub, J.; Rudolf, F.

    2012-12-01

    The use of graphics processing units (GPUs) for the acceleration of general purpose computations has become very attractive over the last years, and accelerators based on many integrated CPU cores are about to hit the market. However, there are discussions about the benefit of GPU computing when comparing the reduction of execution times with the increased development effort [1]. To counter these concerns, our open-source linear algebra library ViennaCL [2,3] uses modern programming techniques such as generic programming in order to provide a convenient access layer for accelerator and GPU computing. Other GPU-accelerated libraries are primarily tuned for performance, but less tailored to productivity and portability: MAGMA [4] provides dense linear algebra operations via a LAPACK-comparable interface, but no dedicated matrix and vector types. Cusp [5] is closest in functionality to ViennaCL for sparse matrices, but is based on CUDA and thus restricted to devices from NVIDIA. However, no convenience layer for dense linear algebra is provided with Cusp. ViennaCL is written in C++ and uses OpenCL to access the resources of accelerators, GPUs and multi-core CPUs in a unified way. On the one hand, the library provides iterative solvers from the family of Krylov methods, including various preconditioners, for the solution of linear systems typically obtained from the discretization of partial differential equations. On the other hand, dense linear algebra operations are supported, including algorithms such as QR factorization and singular value decomposition. The user application interface of ViennaCL is compatible to uBLAS [6], which is part of the peer-reviewed Boost C++ libraries [7]. This allows to port existing applications based on uBLAS with a minimum of effort to ViennaCL. Conversely, the interface compatibility allows to use the iterative solvers from ViennaCL with uBLAS types directly, thus enabling code reuse beyond CPU-GPU boundaries. Out-of-the-box support

  3. Development of an accelerating piston implosion-driven launcher

    NASA Astrophysics Data System (ADS)

    Huneault, J.; Loiseau, J.; Higgins, A. J.

    2014-05-01

    The ability to soft-launch projectiles to velocities exceeding 10 km/s is of interest for a number of scientific fields, including orbital debris impact testing and equation of state research. Current soft-launch technologies have reached a performance plateau below this operating range. In the implosion-driven launcher (ILD) concept, explosives are used to dynamically compress a light driver gas to significantly higher pressures and temperatures than the propellant of conventional light-gas guns. The propellant of the IDL is compressed through the linear implosion of a pressurized tube. The imploding tube behaves like a piston which travels into the light gas at the explosive detonation velocity, thus forming an increasingly long column of shock-compressed gas which can be used to propel a projectile. The McGill designed IDL has demonstrated the ability to launch a 0.1-g projectile to 9.1 km/s. This work will focus on the implementation of a novel launch cycle in which the explosively driven piston is accelerated in order to gradually increase driver gas compression, thus maintaining a relatively constant projectile driving pressure. The theoretical potential of the concept as well as the experimental development of an accelerating piston driver will be examined.

  4. Developing an Accelerator Driven System (ADS) based on electron accelerators and heavy water

    NASA Astrophysics Data System (ADS)

    Feizi, H.; Ranjbar, A. H.

    2016-02-01

    An ADS based on electron accelerators has been developed specifically for energy generation and medical applications. Monte Carlo simulations have been performed using FLUKA code to design a hybrid electron target and the core components. The composition, geometry of conversion targets and the coolant system have been optimized for electron beam energies of 20 to 100 MeV . Furthermore, the photon and photoneutron energy spectra, distribution and energy deposition for various incoming electron beam powers have been studied. Light-heavy water of various mixtures have been used as heat removal for the targets, as γ-n converters and as neutron moderators. We have shown that an electron LINAC, as a neutron production driver for ADSs, is capable of producing a neutron output of > 3.5 × 1014 (n/s/mA). Accordingly, the feasibility of an electron-based ADS employing the designed features is promising for energy generation and high intense neutron production which have various applications such as medical therapies.

  5. Design of RF Feed System for Standing-Wave Accelerator Structures

    SciTech Connect

    Neilson, J.; Tantawi, S.; Dolgashev, V.; /SLAC

    2012-05-25

    We are investigating a standing wave accelerator structure that uses a rf feed to each individual cell. This approach minimizes rf power flow and electromagnetic energy absorbed by an rf breakdown. The objective of this work is a robust high-gradient (above 100 MV/m) X-band accelerator structure.

  6. Progress In Plasma Accelerator Development for Dynamic Formation of Plasma Liners

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Eskridge, Richard; Martin, Adam; Smith, James; Lee, Michael; Cassibry, Jason T.; Griffin, Steven; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    An experimental plasma accelerator for magnetic target fusion (MTF) applications under development at the NASA Marshall Space Flight Center is described. The accelerator is a coaxial pulsed plasma thruster (Figure 1). It has been tested experimentally and plasma jet velocities of approx.50 km/sec have been obtained. The plasma jet has been photographed with 10-ns exposure times to reveal a stable and repeatable plasma structure (Figure 2). Data for velocity profile information has been obtained using light pipes and magnetic probes embedded in the gun walls to record the plasma and current transit respectively at various barrel locations. Preliminary spatially resolved spectral data and magnetic field probe data are also presented. A high speed triggering system has been developed and tested as a means of reducing the gun "jitter". This jitter is being characterized and future work for second generation "ultra-low jitter" gun development is being identified.

  7. Recent Progress in R& D of Advanced Room Temperature Accelerator Structures

    SciTech Connect

    Wang, Juwen

    2003-08-11

    The NLC and JLC groups face two major challenges in designing X-Band accelerator structures for an electron-positron linear collider. The first is to demonstrate stable, long-term operation at a 70 MV/m gradient, which is required to keep the machine cost low, and the second is to strongly suppress the structure long-range wakefield, which is required to achieve high luminosity. During the past 2 years, the major emphasis has been on proving high gradient operation, although dipole wakefield suppression studies are continuing. This paper describes high gradient test results from a series of prototype TW and SW structures being developed for the NLC/JLC. Schemes for damping and detuning the dipole modes of these structures are also presented.

  8. Theory of factors limiting high gradient operation of warm accelerating structures

    SciTech Connect

    Nusinovich, Gregory S.; Antonsen, Thomas M.; Kishek, Rami

    2014-07-25

    This final report summarizes the research performed during the time period from 8/1/2010 to 7/31/2013. It consists of two parts describing our studies in two directions: (a) analysis of factors limiting operation of dielectric-loaded accelerating (DLA) structures where the main problem is the occurrence of multipactor on dielectric surfaces, and (b) studies of effects associated with either RF magnetic or RF electric fields which may cause the RF breakdown in high-gradient metallic accelerating structures. In the studies of DLA structures, at least, two accomplishments should be mentioned: the development of a 3D non-stationary, self-consistent code describing the multipactor phenomena and yielding very good agreement with some experimental data obtained in joint ANL/NRL experiments. In the metallic structures, such phenomena as the heating and melting of micro-particles (metallic dust) by RF electric and magnetic fields in single-shot and rep-rate regimes is analyzed. Also, such processes in micro-protrusions on the structure surfaces as heating and melting due to the field emitted current and the Nottingham effect are thoroughly investigated with the account for space charge of emitted current on the field emission from the tip.

  9. Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

    SciTech Connect

    Turteltaub, K. W.; Bench, G.; Buchholz, B. A.; Enright, H.; Kulp, K.; McCartt, A. D.; Malfatti, M.; Ognibene, T.; Loots, G.; Stewart, B. J.

    2016-04-08

    The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integrated HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory

  10. PRSEUS Structural Concept Development

    NASA Technical Reports Server (NTRS)

    Velicki, Alex; Jegley, Dawn

    2014-01-01

    A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

  11. Formation of electrostatic structures by wakefield acceleration in ultrarelativistic plasma flows: Electron acceleration to cosmic ray energies

    SciTech Connect

    Dieckmann, M.E.; Shukla, P.K.; Eliasson, B.

    2006-06-15

    The ever increasing performance of supercomputers is now enabling kinetic simulations of extreme astrophysical and laser produced plasmas. Three-dimensional particle-in-cell (PIC) simulations of relativistic shocks have revealed highly filamented spatial structures and their ability to accelerate particles to ultrarelativistic speeds. However, these PIC simulations have not yet revealed mechanisms that could produce particles with tera-electron volt energies and beyond. In this work, PIC simulations in one dimension (1D) of the foreshock region of an internal shock in a gamma ray burst are performed to address this issue. The large spatiotemporal range accessible to a 1D simulation enables the self-consistent evolution of proton phase space structures that can accelerate particles to giga-electron volt energies in the jet frame of reference, and to tens of tera-electron volt in the Earth's frame of reference. One potential source of ultrahigh energy cosmic rays may thus be the thermalization of relativistically moving plasma.

  12. Development and beam test of a continuous wave radio frequency quadrupole accelerator

    NASA Astrophysics Data System (ADS)

    Ostroumov, P. N.; Mustapha, B.; Barcikowski, A.; Dickerson, C.; Kolomiets, A. A.; Kondrashev, S. A.; Luo, Y.; Paskvan, D.; Perry, A.; Schrage, D.; Sharamentov, S. I.; Sommer, R.; Toter, W.; Zinkann, G.

    2012-11-01

    The front end of any modern ion accelerator includes a radio frequency quadrupole (RFQ). While many pulsed ion linacs successfully operate RFQs, several ion accelerators worldwide have significant difficulties operating continuous wave (CW) RFQs to design specifications. In this paper we describe the development and results of the beam commissioning of a CW RFQ designed and built for the National User Facility: Argonne Tandem Linac Accelerator System (ATLAS). Several innovative ideas were implemented in this CW RFQ. By selecting a multisegment split-coaxial structure, we reached moderate transverse dimensions for a 60.625-MHz resonator and provided a highly stabilized electromagnetic field distribution. The accelerating section of the RFQ occupies approximately 50% of the total length and is based on a trapezoidal vane tip modulation that increased the resonator shunt impedance by 60% in this section as compared to conventional sinusoidal modulation. To form an axially symmetric beam exiting the RFQ, a very short output radial matcher with a length of 0.75βλ was developed. The RFQ is designed as a 100% oxygen-free electronic (OFE) copper structure and fabricated with a two-step furnace brazing process. The radio frequency (rf) measurements show excellent rf properties for the resonator, with a measured intrinsic Q equal to 94% of the simulated value for OFE copper. An O5+ ion beam extracted from an electron cyclotron resonance ion source was used for the RFQ commissioning. In off-line beam testing, we found excellent coincidence of the measured beam parameters with the results of beam dynamics simulations performed using the beam dynamics code TRACK, which was developed at Argonne. These results demonstrate the great success of the RFQ design and fabrication technology developed here, which can be applied to future CW RFQs.

  13. The ANL experiment for a wake field accelerator using an rf structure

    SciTech Connect

    Ruggiero, A.G.; Schoessow, P.; Simpson, J.

    1986-08-27

    Experiments are planned at ANL to study a new accelerating concept that has been developed during the last few years named the WAKEATRON. This requires a very special, simple configuration of the beams and of the rf structure involved. The basic concepts are explained. Like most proposed experimental work, this too was initiated by a considerable amount of computational work, both analytical and numerical, on which we would like to report. We will then describe details of the planned experiments we will carry out at ANL to check some of our predictions for this concept. These experiments concentrate on beam and cavity geometry applicable to the Wakeatron.

  14. Accelerated cryo-EM structure determination with parallelisation using GPUs in RELION-2

    PubMed Central

    Kimanius, Dari; Forsberg, Björn O; Scheres, Sjors HW; Lindahl, Erik

    2016-01-01

    By reaching near-atomic resolution for a wide range of specimens, single-particle cryo-EM structure determination is transforming structural biology. However, the necessary calculations come at large computational costs, which has introduced a bottleneck that is currently limiting throughput and the development of new methods. Here, we present an implementation of the RELION image processing software that uses graphics processors (GPUs) to address the most computationally intensive steps of its cryo-EM structure determination workflow. Both image classification and high-resolution refinement have been accelerated more than an order-of-magnitude, and template-based particle selection has been accelerated well over two orders-of-magnitude on desktop hardware. Memory requirements on GPUs have been reduced to fit widely available hardware, and we show that the use of single precision arithmetic does not adversely affect results. This enables high-resolution cryo-EM structure determination in a matter of days on a single workstation. DOI: http://dx.doi.org/10.7554/eLife.18722.001 PMID:27845625

  15. Expert Cold Structure Development

    NASA Astrophysics Data System (ADS)

    Atkins, T.; Demuysere, P.

    2011-05-01

    The EXPERT Program is funded by ESA. The objective of the EXPERT mission is to perform a sub-orbital flight during which measurements of critical aero- thermodynamic phenomena will be obtained by using state-of-the-art instrumentation. As part of the EXPERT Flight Segment, the responsibility of the Cold Structure Development Design, Manufacturing and Validation was committed to the Belgian industrial team SONACA/SABCA. The EXPERT Cold Structure includes the Launcher Adapter, the Bottom Panel, the Upper Panel, two Cross Panels and the Parachute Bay. An additional Launcher Adapter was manufactured for the separation tests. The selected assembly definition and manufacturing technologies ( machined parts and sandwich panels) were dictated classically by the mass and stiffness, but also by the CoG location and the sensitive separation interface. Used as support for the various on-board equipment, the Cold Structure is fixed to but thermally uncoupled from the PM 1000 thermal shield. It is protect on its bottom panel by a thermal blanket. As it is a protoflight, analysis was the main tool for the verification. Low level stiffness and modal analysis tests have also been performed on the Cold Structure equipped with its ballast. It allowed to complete its qualification and to prepare SONACA/SABCA support for the system dynamic tests foreseen in 2011. The structure was finally coated with a thermal control black painting and delivered on time to Thales Alenia Space-Italy end of March 201.

  16. Accelerating Adverse Outcome Pathway Development Using Publicly Available Data Sources.

    PubMed

    Oki, Noffisat O; Nelms, Mark D; Bell, Shannon M; Mortensen, Holly M; Edwards, Stephen W

    2016-03-01

    The adverse outcome pathway (AOP) concept links molecular perturbations with organism and population-level outcomes to support high-throughput toxicity (HTT) testing. International efforts are underway to define AOPs and store the information supporting these AOPs in a central knowledge base; however, this process is currently labor-intensive and time-consuming. Publicly available data sources provide a wealth of information that could be used to define computationally predicted AOPs (cpAOPs), which could serve as a basis for creating expert-derived AOPs in a much more efficient way. Computational tools for mining large datasets provide the means for extracting and organizing the information captured in these public data sources. Using cpAOPs as a starting point for expert-derived AOPs should accelerate AOP development. Coupling this with tools to coordinate and facilitate the expert development efforts will increase the number and quality of AOPs produced, which should play a key role in advancing the adoption of HTT testing, thereby reducing the use of animals in toxicity testing and greatly increasing the number of chemicals that can be tested.

  17. Accelerating Technology Development through Integrated Computation and Experimentation

    SciTech Connect

    Shekhawat, Dushyant; Srivastava, Rameshwar D.; Ciferno, Jared; Litynski, John; Morreale, Bryan D.

    2013-08-15

    This special section of Energy & Fuels comprises a selection of papers presented at the topical conference “Accelerating Technology Development through Integrated Computation and Experimentation”, sponsored and organized by the United States Department of Energy’s National Energy Technology Laboratory (NETL) as part of the 2012 American Institute of Chemical Engineers (AIChE) Annual Meeting held in Pittsburgh, PA, Oct 28-Nov 2, 2012. That topical conference focused on the latest research and development efforts in five main areas related to fossil energy, with each area focusing on the utilization of both experimental and computational approaches: (1) gas separations (membranes, sorbents, and solvents for CO{sub 2}, H{sub 2}, and O{sub 2} production), (2) CO{sub 2} utilization (enhanced oil recovery, chemical production, mineralization, etc.), (3) carbon sequestration (flow in natural systems), (4) advanced power cycles (oxy-combustion, chemical looping, gasification, etc.), and (5) fuel processing (H{sub 2} production for fuel cells).

  18. Numerically optimized structures for dielectric asymmetric dual-grating laser accelerators

    SciTech Connect

    Aimidula, A.; Bake, M. A.; Wan, F.; Xie, B. S.; Welsch, C. P.; Xia, G.; Mete, O.; Uesaka, M.; Matsumura, Y.; Yoshida, M.; Koyama, K.

    2014-02-15

    Optical scale dielectric structures are promising candidates to realize future compact, low cost particle accelerators, since they can sustain high acceleration gradients in the range of GeV/m. Here, we present numerical simulation results for a dielectric asymmetric dual-grating accelerator. It was found that the asymmetric dual-grating structures can efficiently modify the laser field to synchronize it with relativistic electrons, therefore increasing the average acceleration gradient by ∼10% in comparison to symmetric structures. The optimum pillar height which was determined by simulation agrees well with that estimated analytically. The effect of the initial kinetic energy of injected electrons on the acceleration gradient is also discussed. Finally, the required laser parameters were calculated analytically and a suitable laser is proposed as energy source.

  19. Computer simulation of the coupling slots effects for on-axis coupled accelerating structures.

    NASA Astrophysics Data System (ADS)

    Salakhoutdinov, A. F.; Shvedunov, V. I.

    1997-05-01

    The presence of coupling elements in accelerating structures leads to the violation of axial symmetry of accelerating field and it may cause displacement, defocusing and non-linear distortion of phase space. As a result the growth of transverse emittance occures. From the other hand, these effects may be used for designing of RF- focusing accelerating structure for electron accelerators of various types. The numerical simulation of electrodynamical properties of on-axis coupled accelerating structure taking into account the coupling slots have been made. The characteristics of fields excited within the coupling cell have been investigated. The numerical estimations of various multipolarity components of transverse forces acting upon a particle inside the coupling cell have been achieved.

  20. Experimental demonstration of wakefield effects in a THz planar diamond accelerating structure

    SciTech Connect

    Antipov, S.; Jing, C.; Kanareykin, A.; Butler, J. E.; Yakimenko, V.; Fedurin, M.; Kusche, K.; Gai, W.

    2012-03-26

    We have directly measured THz wakefields induced by a subpicosecond, intense relativistic electron bunch in a diamond loaded accelerating structure via the wakefield acceleration method. We present here the beam test results from the diamond based structure. Diamond has been chosen for its high breakdown threshold and unique thermoconductive properties. Fields produced by a leading (drive) beam were used to accelerate a trailing (witness) electron bunch, which followed the drive bunch at a variable distance. The energy gain of a witness bunch as a function of its separation from the drive bunch describes the time structure of the generated wakefield.

  1. Particle motion of accelerated electrons in standing-wave RF structures

    NASA Astrophysics Data System (ADS)

    Hammen, A. F. J.; Corstens, J. M.; Botman, J. I. M.; Hagedoorn, H. L.; Theuws, W. H. C.

    1999-05-01

    A Hamiltonian theory has been formulated, which is used to calculate accelerated particle motion in standing-wave RF structures. In particular, these calculations have been applied to the Eindhoven racetrack microtron accelerating cavity. The calculations are in excellent agreement with simulations performed by particle-tracking codes.

  2. Linear particle accelerator with seal structure between electrodes and insulators

    DOEpatents

    Broadhurst, John H.

    1989-01-01

    An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

  3. Free electron laser using Rf coupled accelerating and decelerating structures

    DOEpatents

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1984-01-01

    A free electron laser and free electron laser amplifier using beam transport devices for guiding an electron beam to a wiggler of a free electron laser and returning the electron beam to decelerating cavities disposed adjacent to the accelerating cavities of the free electron laser. Rf energy is generated from the energy depleted electron beam after it emerges from the wiggler by means of the decelerating cavities which are closely coupled to the accelerating cavities, or by means of a second bore within a single set of cavities. Rf energy generated from the decelerated electron beam is used to supplement energy provided by an external source, such as a klystron, to thereby enhance overall efficiency of the system.

  4. Accelerated Nuclear Energy Materials Development with Multiple Ion Beams

    SciTech Connect

    Fluss, M J; Bench, G

    2009-08-19

    A fundamental issue in nuclear energy is the changes in material properties as a consequence of time, temperature, and neutron fluence. Usually, candidate materials for nuclear energy applications are tested in nuclear reactors to understand and model the changes that arise from a combination of atomic displacements, helium and hydrogen production, and other nuclear transmutations (e.g. fission and the production of fission products). Experiments may be carried out under neutron irradiation conditions in existing nuclear materials test reactors (at rates of 10 to 20 displacements per atom (DPA) per year or burn-up rates of a few percent per year for fertile fuels), but such an approach takes much too long for many high neutron fluence scenarios (300 DPA for example) expected in reactors of the next generation. Indeed it is reasonable to say that there are no neutron sources available today to accomplish sufficiently rapid accelerated aging let alone also provide the temperature and spectral characteristics of future fast spectrum nuclear energy systems (fusion and fission both). Consequently, materials research and development progress continues to be severely limited by this bottleneck.

  5. Vibration-Based Method Developed to Detect Cracks in Rotors During Acceleration Through Resonance

    NASA Technical Reports Server (NTRS)

    Sawicki, Jerzy T.; Baaklini, George Y.; Gyekenyesi, Andrew L.

    2004-01-01

    In recent years, there has been an increasing interest in developing rotating machinery shaft crack-detection methodologies and online techniques. Shaft crack problems present a significant safety and loss hazard in nearly every application of modern turbomachinery. In many cases, the rotors of modern machines are rapidly accelerated from rest to operating speed, to reduce the excessive vibrations at the critical speeds. The vibration monitoring during startup or shutdown has been receiving growing attention (ref. 1), especially for machines such as aircraft engines, which are subjected to frequent starts and stops, as well as high speeds and acceleration rates. It has been recognized that the presence of angular acceleration strongly affects the rotor's maximum response to unbalance and the speed at which it occurs. Unfortunately, conventional nondestructive evaluation (NDE) methods have unacceptable limits in terms of their application for online crack detection. Some of these techniques are time consuming and inconvenient for turbomachinery service testing. Almost all of these techniques require that the vicinity of the damage be known in advance, and they can provide only local information, with no indication of the structural strength at a component or system level. In addition, the effectiveness of these experimental techniques is affected by the high measurement noise levels existing in complex turbomachine structures. Therefore, the use of vibration monitoring along with vibration analysis has been receiving increasing attention.

  6. Methodology for the structural design of single spoke accelerating cavities at Fermilab

    NASA Astrophysics Data System (ADS)

    Passarelli, Donato; Wands, Robert H.; Merio, Margherita; Ristori, Leonardo

    2016-10-01

    Fermilab is planning to upgrade its accelerator complex to deliver a more powerful and intense proton-beam for neutrino experiments. In the framework of the so-called Proton Improvement Plan-II (PIP-II), we are designing and developing a cryomodule containing superconducting accelerating cavities, the Single Spoke Resonators of type 1 (SSR1). In this paper, we present the sequence of analysis and calculations performed for the structural design of these cavities, using the rules of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC). The lack of an accepted procedure for addressing the design, fabrication, and inspection of such unique pressure vessels makes the task demanding and challenging every time. Several factors such as exotic materials, unqualified brazing procedures, limited nondestructive examination, and the general R&D nature of these early generations of cavity design, conspire to make it impractical to obtain full compliance with all ASME BPVC requirements. However, the presented approach allowed us to validate the design of this new generation of single spoke cavities with values of maximum allowable working pressure that exceeds the safety requirements. This set of rules could be used as a starting point for the structural design and development of similar objects.

  7. Methodology for the structural design of single spoke accelerating cavities at Fermilab

    DOE PAGES

    Passarelli, Donato; Wands, Robert H.; Merio, Margherita; ...

    2016-10-01

    Fermilab is planning to upgrade its accelerator complex to deliver a more powerful and intense proton-beam for neutrino experiments. In the framework of the so-called Proton Improvement Plan-II (PIP-II), we are designing and developing a cryomodule containing superconducting accelerating cavities, the Single Spoke Resonators of type 1 (SSR1). In this paper, we present the sequence of analysis and calculations performed for the structural de- sign of these cavities, using the rules of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC). The lack of an accepted procedure for addressing the design, fabrication, and inspection of suchmore » unique pressure vessels makes the task demanding and challenging every time. Several factors such as exotic materials, unqualified brazing procedures, limited nondestructive examination, and the general R&D nature of these early generations of cavity design, conspire to make it impractical to obtain full compliance with all ASME BPVC requirements. However, the presented approach allowed us to validate the design of these new generation of single spoke cavities with values of maximum allowable working pressure that exceed the safety requirements. This set of rules could be used as a starting point for the structural design and development of similar objects.« less

  8. Methodology for the structural design of single spoke accelerating cavities at Fermilab

    SciTech Connect

    Passarelli, Donato; Wands, Robert H.; Merio, Margherita; Ristori, Leonardo

    2016-10-01

    Fermilab is planning to upgrade its accelerator complex to deliver a more powerful and intense proton-beam for neutrino experiments. In the framework of the so-called Proton Improvement Plan-II (PIP-II), we are designing and developing a cryomodule containing superconducting accelerating cavities, the Single Spoke Resonators of type 1 (SSR1). In this paper, we present the sequence of analysis and calculations performed for the structural de- sign of these cavities, using the rules of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC). The lack of an accepted procedure for addressing the design, fabrication, and inspection of such unique pressure vessels makes the task demanding and challenging every time. Several factors such as exotic materials, unqualified brazing procedures, limited nondestructive examination, and the general R&D nature of these early generations of cavity design, conspire to make it impractical to obtain full compliance with all ASME BPVC requirements. However, the presented approach allowed us to validate the design of these new generation of single spoke cavities with values of maximum allowable working pressure that exceed the safety requirements. This set of rules could be used as a starting point for the structural design and development of similar objects.

  9. GeauxDock: Accelerating Structure-Based Virtual Screening with Heterogeneous Computing.

    PubMed

    Fang, Ye; Ding, Yun; Feinstein, Wei P; Koppelman, David M; Moreno, Juana; Jarrell, Mark; Ramanujam, J; Brylinski, Michal

    2016-01-01

    Computational modeling of drug binding to proteins is an integral component of direct drug design. Particularly, structure-based virtual screening is often used to perform large-scale modeling of putative associations between small organic molecules and their pharmacologically relevant protein targets. Because of a large number of drug candidates to be evaluated, an accurate and fast docking engine is a critical element of virtual screening. Consequently, highly optimized docking codes are of paramount importance for the effectiveness of virtual screening methods. In this communication, we describe the implementation, tuning and performance characteristics of GeauxDock, a recently developed molecular docking program. GeauxDock is built upon the Monte Carlo algorithm and features a novel scoring function combining physics-based energy terms with statistical and knowledge-based potentials. Developed specifically for heterogeneous computing platforms, the current version of GeauxDock can be deployed on modern, multi-core Central Processing Units (CPUs) as well as massively parallel accelerators, Intel Xeon Phi and NVIDIA Graphics Processing Unit (GPU). First, we carried out a thorough performance tuning of the high-level framework and the docking kernel to produce a fast serial code, which was then ported to shared-memory multi-core CPUs yielding a near-ideal scaling. Further, using Xeon Phi gives 1.9× performance improvement over a dual 10-core Xeon CPU, whereas the best GPU accelerator, GeForce GTX 980, achieves a speedup as high as 3.5×. On that account, GeauxDock can take advantage of modern heterogeneous architectures to considerably accelerate structure-based virtual screening applications. GeauxDock is open-sourced and publicly available at www.brylinski.org/geauxdock and https://figshare.com/articles/geauxdock_tar_gz/3205249.

  10. GeauxDock: Accelerating Structure-Based Virtual Screening with Heterogeneous Computing

    PubMed Central

    Fang, Ye; Ding, Yun; Feinstein, Wei P.; Koppelman, David M.; Moreno, Juana; Jarrell, Mark; Ramanujam, J.; Brylinski, Michal

    2016-01-01

    Computational modeling of drug binding to proteins is an integral component of direct drug design. Particularly, structure-based virtual screening is often used to perform large-scale modeling of putative associations between small organic molecules and their pharmacologically relevant protein targets. Because of a large number of drug candidates to be evaluated, an accurate and fast docking engine is a critical element of virtual screening. Consequently, highly optimized docking codes are of paramount importance for the effectiveness of virtual screening methods. In this communication, we describe the implementation, tuning and performance characteristics of GeauxDock, a recently developed molecular docking program. GeauxDock is built upon the Monte Carlo algorithm and features a novel scoring function combining physics-based energy terms with statistical and knowledge-based potentials. Developed specifically for heterogeneous computing platforms, the current version of GeauxDock can be deployed on modern, multi-core Central Processing Units (CPUs) as well as massively parallel accelerators, Intel Xeon Phi and NVIDIA Graphics Processing Unit (GPU). First, we carried out a thorough performance tuning of the high-level framework and the docking kernel to produce a fast serial code, which was then ported to shared-memory multi-core CPUs yielding a near-ideal scaling. Further, using Xeon Phi gives 1.9× performance improvement over a dual 10-core Xeon CPU, whereas the best GPU accelerator, GeForce GTX 980, achieves a speedup as high as 3.5×. On that account, GeauxDock can take advantage of modern heterogeneous architectures to considerably accelerate structure-based virtual screening applications. GeauxDock is open-sourced and publicly available at www.brylinski.org/geauxdock and https://figshare.com/articles/geauxdock_tar_gz/3205249. PMID:27420300

  11. Using Machine Learning to Accelerate Complex Atomic Structure Elucidation

    NASA Astrophysics Data System (ADS)

    Brouwer, William; Calderin, Lazaro; Sofo, Jorge

    2012-02-01

    Workers in various scientific disciplines seek to develop chemical models for extended and molecular systems. The modeling process revolves around the gradual refinement of model assumptions, through comparison of experimental and computational results. Solid state Nuclear Magnetic Resonance (NMR) is one such experimental technique, providing great insight into chemical order over Angstrom length scales. However, interpretation of spectra for complex materials is difficult, often requiring intensive simulations. Similarly, working forward from the model in order to produce experimental quantities via ab initio is computationally demanding. The work involved in these two significant steps, compounded by the need to iterate back and forth, drastically slows the discovery process for new materials. There is thus great motivation for the derivation of structural models directly from complex experimental data, the subject of this work. Using solid state NMR experimental datasets, in conjunction with ab initio calculations of measurable NMR parameters, a network of machine learning kernels are trained to rapidly yield structural details, on the basis of input NMR spectra. Results for an environmentally relevant material will be presented, and directions for future work.

  12. Acceleration of the GAMESS-UK electronic structure package on graphical processing units.

    PubMed

    Wilkinson, Karl A; Sherwood, Paul; Guest, Martyn F; Naidoo, Kevin J

    2011-07-30

    The approach used to calculate the two-electron integral by many electronic structure packages including generalized atomic and molecular electronic structure system-UK has been designed for CPU-based compute units. We redesigned the two-electron compute algorithm for acceleration on a graphical processing unit (GPU). We report the acceleration strategy and illustrate it on the (ss|ss) type integrals. This strategy is general for Fortran-based codes and uses the Accelerator compiler from Portland Group International and GPU-based accelerators from Nvidia. The evaluation of (ss|ss) type integrals within calculations using Hartree Fock ab initio methods and density functional theory are accelerated by single and quad GPU hardware systems by factors of 43 and 153, respectively. The overall speedup for a single self consistent field cycle is at least a factor of eight times faster on a single GPU compared with that of a single CPU.

  13. Technological issues and high gradient test results on X-band molybdenum accelerating structures

    NASA Astrophysics Data System (ADS)

    Spataro, B.; Alesini, D.; Chimenti, V.; Dolgashev, V.; Haase, A.; Tantawi, S. G.; Higashi, Y.; Marrelli, C.; Mostacci, A.; Parodi, R.; Yeremian, A. D.

    2011-11-01

    Two 11.424 GHz single cell standing wave accelerating structures have been fabricated for high gradient RF breakdown studies. Both are brazed structures: one made from copper and the other from sintered molybdenum bulk. The tests results are presented and compared to those of similar devices constructed at SLAC ( Stanford Linear Accelerator Center) and KEK ( Kō Enerugī Kasokuki Kenkyū Kikō). The technological issues to build both sections are discussed.

  14. Technological Issues and High Gradient Test Results on X-Band Molybdenum Accelerating Structures

    SciTech Connect

    Spataro, B.; Alesini, D.; Chimenti, V.; Dolgashev, V.; Haase, A.; Tantawi, S.G.; Higashi, Y.; Marrelli, C.; Mostacci, A.; Parodi, R.; Yeremian, A.D.; /SLAC

    2012-04-24

    Two 11.424 GHz single cell standing wave accelerating structures have been fabricated for high gradient RF breakdown studies. Both are brazed structures: one made from copper and the other from sintered molybdenum bulk. The tests results are presented and compared to those of similar devices constructed at SLAC (Stanford Linear Accelerator Center) and KEK (Ko Enerugi Kasokuki Kenkyu Kiko). The technological issues to build both sections are discussed.

  15. Development of an ion beam analyzing system for the KBSI heavy-ion accelerator

    SciTech Connect

    Bahng, Jungbae; Hong, Jonggi; Park, Jin Yong; Kim, Seong Jun; Ok, Jung-Woo; Choi, Seyong; Shin, Chang Seouk; Yoon, Jang-Hee; Won, Mi-Sook; Lee, Byoung-Seob; Kim, Eun-San

    2016-02-15

    The Korea Basic Science Institute (KBSI) has been developing a heavy ion accelerator system to accelerate high current, multi-charge state ions produced by a 28 GHz superconducting electron cyclotron ion source. A beam analyzing system as a part of the low energy beam transport apparatus was developed to select charged particles with desirable charge states from the ion beams. The desired species of ion, which is generated and extracted from the ECR ion source including various ion particles, can be selected by 90° dipole electromagnet. Due to the non-symmetrical structure in the coil as well as the non-linear permeability of the yoke material coil, a three dimensional analysis was carried out to confirm the design parameters. In this paper, we present the experimental results obtained as result of an analysis of KBSI accelerator. The effectiveness of beam selection was confirmed during the test of the analyzing system by injecting an ion beam from an ECR ion source.

  16. Development of an ion beam analyzing system for the KBSI heavy-ion accelerator

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Hong, Jonggi; Park, Jin Yong; Kim, Seong Jun; Ok, Jung-Woo; Choi, Seyong; Shin, Chang Seouk; Yoon, Jang-Hee; Won, Mi-Sook; Lee, Byoung-Seob; Kim, Eun-San

    2016-02-01

    The Korea Basic Science Institute (KBSI) has been developing a heavy ion accelerator system to accelerate high current, multi-charge state ions produced by a 28 GHz superconducting electron cyclotron ion source. A beam analyzing system as a part of the low energy beam transport apparatus was developed to select charged particles with desirable charge states from the ion beams. The desired species of ion, which is generated and extracted from the ECR ion source including various ion particles, can be selected by 90° dipole electromagnet. Due to the non-symmetrical structure in the coil as well as the non-linear permeability of the yoke material coil, a three dimensional analysis was carried out to confirm the design parameters. In this paper, we present the experimental results obtained as result of an analysis of KBSI accelerator. The effectiveness of beam selection was confirmed during the test of the analyzing system by injecting an ion beam from an ECR ion source.

  17. Accelerator developments since the ZGS by ZGS people

    SciTech Connect

    Cho, Y.

    1994-12-31

    The ZGS was a facility, as well as an organization, where people got together to pursue a common goal of doing exciting science of the day. In this note, the authors describe notable events related to accelerators and accelerator people since the closing of the ZGS program some 15 years ago. Many of the same ZGS people have been carrying out the state-of-the art accelerator work around the Laboratory with the same dedication that characterized their work in the earlier days. First the authors describe how the activities were re-organized after the closing of the ZGS, the migration of people, and the organizational evolution since that time. Doing this shows the similarity between the birth of the ZGS and the birth of the Advanced Photon Source (APS). Then, some of the accelerator work by the former ZGS people are described. These include: (1) Intense Pulsed Neutron Source (IPNS), (2) GeV Electron Microtron (GEM), (3) Wake Field Accelerator Test Facility, (4) Advanced Photon Source, and (5) IPNS Upgrade.

  18. Guided post-acceleration of laser-driven ions by a miniature modular structure

    NASA Astrophysics Data System (ADS)

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-04-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m-1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications.

  19. Guided post-acceleration of laser-driven ions by a miniature modular structure.

    PubMed

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L S; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P L; Schroer, Anna M; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-04-18

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m(-1), already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications.

  20. The development of seismic guidelines for the Stanford Linear Accelerator Center

    SciTech Connect

    Huggins, R.

    1996-08-01

    This paper describes the development of Seismic Guidelines for the Stanford Linear Accelerator Center (SLAC). Although structures have always been built conservatively, SLAC management decided to review and update their seismic guidelines. SLAC is about mid-way between the epicenters of the 8.3 Richter magnitude 1906 San Francisco and the 7.2 Loma Prieta Earthquakes. The west end of the two mile long electron/positron particle accelerator lies a half mile from the large San Andreas Fault. Suggestions for seismic planning processes were solicited from local computer manufacturing firms, universities, and federal laboratories. A Committee of the various stakeholders in SLAC`s seismic planning retained an internationally known Seismic Planning Consultant and reviewed relevant standards and drafted Guidelines. A panel of seismic experts was convened to help define the hazard, site response spectra, probabilistic analysis of shaking, and near field effects. The Facility`s structures were assigned to seismic classes of importance, and an initial assessment of a sample of a dozen buildings conducted. This assessment resulted in emergency repairs to one structure, and provided a {open_quotes}reality basis{close_quotes} for establishing the final Guidelines and Administrative Procedures, and a program to evaluate remaining buildings, shielding walls, tunnels, and other special structures.

  1. Residual acceleration data on IML-1: Development of a data reduction and dissemination plan

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. Iwan D.; Wolf, Randy

    1991-01-01

    A residual acceleration data analysis plan is developed that will allow principal investigators of low-gravity experiments to efficiently process their experimental results in conjunction with accelerometer data. The basic approach consisted of the following program of research: (1) identification of sensitive experiments and sensitivity ranges by order of magnitude estimates, numerical modelling, and investigator input; (2) research and development towards reduction, supplementation, and dissemination of residual acceleration data; and (3) implementation of the plan on existing acceleration data bases.

  2. Particle Acceleration at Filamentary Structures Downstream of Collisionless Shocks in the Heliosphere.

    NASA Astrophysics Data System (ADS)

    Kucharek, H.; Pogorelov, N. V.; Gamayunov, K. V.

    2015-12-01

    Collisionless shocks are an important feature in astrophysical, heliospheric and magnetospheric settings. At these structures plasma is heated, the properties of flows are changed, and particles are accelerated to high energies. Particles are accelerated throughout the heliosphere. There are no times or conditions where suprathermal ions forming tails are not present on the solar wind ion distribution, and given the low speeds of these particles they must be accelerated locally in the heliosphere. Coronal mass ejections (CMEs) and co-rotating interaction regions (CIRs) accelerate particles up to 10s of MeV/nucleon. The termination shock of the solar and the heliosheath produce energetic particles including the Anomalous Cosmic Rays (ACRs), with energies in excess of 100 MeV. In the last few years' very interesting observations at low energies showing power laws that cannot be explained with commonly accepted acceleration mechanisms and thus increased the need for alternative acceleration processes. Fully consistent kinetic particle simulations such as hybrid simulations appear to be a powerful tool to investigated ion acceleration. Nowadays these simulations can be performed in 3D and relative large simulation domains covering up to hundreds of ion inertial length in size and thus representing the MHD scale. These 3D hybrid simulations show filamentary magnetic and density structures, which could be interpreted as small-scale flux ropes. The growth of these small-scale structures is also associated with ion acceleration. In this talk we will discuss properties of these filamentary structures, their spatial and temporal evolution and the particle dynamics during the acceleration process. The results of this study may be of particular importance for future high resolution magnetospheric and heliospheric mission such as THOR.

  3. Studies of Multipactor in Dielectric-Loaded Accelerator Structures: Comparison of Simulation Results with Experimental Data

    SciTech Connect

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas Jr.

    2010-11-04

    In this paper new results of numerical studies of multipactor in dielectric-loaded accelerator structures are presented. The results are compared with experimental data obtained during recent studies of such structures performed by Argonne National Laboratory, the Naval Research Laboratory, SLAC National Accelerator Laboratory and Euclid TechLabs, LLC. Good agreement between the theory and experiment was observed for the structures with larger inner diameter, however the structures with smaller inner diameter demonstrated a discrepancy between the two. Possible reasons for such discrepancy are discussed.

  4. Laser acceleration and deflection of 963 keV electrons with a silicon dielectric structure

    DOE PAGES

    Leedle, Kenneth J.; Pease, R. Fabian; Byer, Robert L.; ...

    2015-02-12

    Radio frequency particle accelerators are ubiquitous in ultrasmall and ultrafast science, but their size and cost have prompted exploration of compact and scalable alternatives such as the dielectric laser accelerator. We present the first demonstration, to the best of our knowledge, of high gradient laser acceleration and deflection of electrons with a silicon structure. Driven by a 5 nJ, 130 fs mode-locked Ti:sapphire laser at 907 nm wavelength, our devices achieve accelerating gradients in excess of 200 MeV/m and suboptical cycle streaking of 96.30 keV electrons. These results pave the way for high gradient silicon dielectric laser accelerators using commercialmore » lasers and subfemtosecond electron beam experiments.« less

  5. Advanced laser particle accelerator development at LANL: from fast ignition to radiation oncology

    SciTech Connect

    Flippo, Kirk A; Gaillard, Sandrine A; Offermann, D T; Cobble, J A; Schmitt, M J; Gautier, D C; Kwan, T J T; Montgomery, D S; Kluge, Thomas; Bussmann, Micheal; Bartal, T; Beg, F N; Gall, B; Geissel, M; Korgan, G; Kovaleski, S; Lockard, T; Malekos, S; Schollmeier, M; Sentoku, Y; Cowan, T E

    2010-01-01

    Laser-plasma accelerated ion and electron beam sources are an emerging field with vast prospects, and promise many superior applications in a variety of fields such as hadron cancer therapy, compact radioisotope generation, table-top nuclear physics, laboratory astrophysics, nuclear forensics, waste transmutation, SN M detection, and inertial fusion energy. LANL is engaged in several projects seeking to develop compact high current and high energy ion and electron sources. We are especially interested in two specific applications: ion fast ignition/capsule perturbation and radiation oncology in conjunction with our partners at the ForschungsZentrum Dresden-Rossendorf (FZD). Laser-to-beam conversion efficiencies of over 10% are needed for practical applications, and we have already shown inherent etliciencies of >5% from flat foils, on Trident using only a 5th of the intensity and energy of the Nova Petawatt. With clever target designs, like structured curved cone targets, we have also been able to achieve major ion energy gains, leading to the highest energy laser-accelerated proton beams in the world. These new target designs promise to help usher in the next generation of particle sources realizing the potential of laser-accelerated beams.

  6. Accelerator production of tritium plant design and supporting engineering development and demonstration work

    SciTech Connect

    Lisowski, P.W.

    1997-11-01

    Tritium is an isotope of hydrogen with a half life of 12.3 years. Because it is essential for US thermonuclear weapons to function, tritium must be periodically replenished. Since K reactor at Savannah River Site stopped operating in 1988, tritium has been recycled from dismantled nuclear weapons. This process is possible only as long as many weapons are being retired. Maintaining the stockpile at the level called for in the present Strategic Arms Reduction Treaty (START-I) will require the Department of Energy to have an operational tritium production capability in the 2005--2007 time frame. To make the required amount of tritium using an accelerator based system (APT), neutrons will be produced through high energy proton reactions with tungsten and lead. Those neutrons will be moderated and captured in {sup 3}He to make tritium. The APT plant design will use a 1,700 MeV linear accelerator operated at 100 mA. In preparation for engineering design, starting in October 1997 and subsequent construction, a program of engineering development and demonstration is underway. That work includes assembly and testing of the first 20 MeV of the low energy plant linac at 100 mA, high-energy linac accelerating structure prototyping, radiofrequency power system improvements, neutronic efficiency measurements, and materials qualifications.

  7. Advanced Laser Particle Accelerator Development at LANL: From Fast Ignition to Radiation Oncology

    SciTech Connect

    Flippo, K. A.; Offermann, D. T.; Cobble, J. A.; Schmitt, M. J.; Gautier, D. C.; Kwan, T. J.; Montgomery, D. S.; Gaillard, S. A.; Kluge, T.; Bussmann, M.; Cowan, T. E.; Bartal, T.; Beg, F. N.; Gall, B.; Kovaleski, S.; Geissel, M.; Schollmeier, M.; Korgan, G.; Malekos, S.; Lockard, T.

    2010-11-04

    Laser-plasma accelerated ion and electron beam sources are an emerging field with vast prospects, and promise many superior applications in a variety of fields such as hadron cancer therapy, compact radioisotope generation, table-top nuclear physics, laboratory astrophysics, nuclear forensics, waste transmutation, Special Nuclear Material (SNM) detection, and inertial fusion energy. LANL is engaged in several projects seeking to develop compact high-current and high-energy ion and electron sources. We are especially interested in two specific applications: ion fast ignition/capsule perturbation and radiation oncology. Laser-to-beam conversion efficiencies of over 10% are needed for practical applications, and we have already shown inherent efficiencies of >5% from flat foils, on Trident using only a 5th of the intensity and energy of the Nova Petawatt laser. With clever target designs, like structured curved cone targets, we have also been able to achieve major ion energy gains, leading to the highest energy laser-accelerated proton beams in the world [3]. These new target designs promise to help usher in the next generation of particle sources realizing the potential of laser-accelerated beams.

  8. RF Processing of X-Band Accelerator Structures at the NLCTA

    SciTech Connect

    Adolphsen, Chris

    2000-08-24

    During the initial phase of operation, the linacs of the Next Linear Collider (NLC) will contain roughly 5,000 X-Band accelerator structures that will accelerate beams of electrons and positrons to 250 GeV. These structures will nominally operate at an unloaded gradient of 72 MV/m. As part of the NLC R and D program, several prototype structures have been built and operated at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. Here, the effect of high gradient operation on the structure performance has been studied. Significant progress was made during the past year after the NLCTA power sources were upgraded to reliably produce the required NLC power levels and beyond. This paper describes the structures, the processing methodology and the observed effects of high gradient operation.

  9. Accelerating materials discovery through the development of polymer databases

    NASA Astrophysics Data System (ADS)

    Audus, Debra

    In our line of business we create chemical solutions for a wide range of applications, such as home and personal care, printing and packaging, automotive and structural coatings, and structural plastics and foams applications. In this environment, stable and highly automated workflows suitable to handle complex systems are a must. By satisfying these prerequisites, efficiency for the development of new materials can be significantly improved by combining modeling and experimental approaches. This is in fact in line with recent Materials Genome Initiative efforts sponsored by the US administration. From our experience, we know, that valuable contributions to product development are possible today by combining existing modeling techniques in an intelligent fashion, provided modeling and experiment work closely together. In my presentation I intend to review approaches to build and parameterize soft matter systems. As an example of our standard workflow, I will show a few applications, which include the design of a stabilizer molecule for dispersing polymer particles and the simulation of polystyrene dispersions.

  10. High Gradient Performance of NLC/GLC X-band Accelerating Structures

    SciTech Connect

    Doebert, S.; Adolphsen, C.; Bowden, G.; Burke, D.; Chan, J.; Dolgashev, V.; Frisch, J.; Jobe, K.; Jones, R.; Lewandowski, J.; Kirby, R.; Li, Z.; McCormick, D.; Miller, R.; Nantista, C.; Nelson, J.; Pearson, C.; Ross, M.; Schultz, D.; Smith, T.; Tantawi, S.; /SLAC /Fermilab /KEK, Tsukuba

    2005-05-17

    During the past five years, there has been a concerted program at SLAC and KEK to develop accelerator structures that meet the high gradient (65 MV/m) performance requirements for the Next Linear Collider (NLC) and Global Linear Collider (GLC) initiatives. The design that resulted is a 60-cm-long, traveling-wave structure with low group velocity and 150 degree per cell phase advance. It has an average iris size that produces an acceptable short-range wakefield, and dipole mode damping and detuning that adequately suppresses the long-range wakefield. More than eight such structures have operated at a 60 Hz repetition rate over 1000 hours at 65 MV/m with 400 ns long pulses, and have reached breakdown rate levels below the limit for the linear collider. Moreover, the structures are robust in that the rates continue to decrease over time, and if the structures are briefly exposed to air, the rates recover to their low levels within a few days. This paper presents a summary of the results from this program, which effectively ended last August with the selection of ''cold'' technology for an International Linear Collider (ILC).

  11. On a theory of two-beam mechanisms of charged particle acceleration in electrodynamic structures

    SciTech Connect

    Ostrovsky, A.O.

    1993-09-01

    This work is devoted to the theoretical studies of two-beam mechanisms of charged particle acceleration in electronic structures. The first section continues the outline of results of theoretical studies commenced in the intermediate report and considers the two-beam scheme of acceleration in the plasma waveguide. According to this scheme the strong current relativistic electron beam (REB) excites the intensive plasma waves accelerating the electrons of the second beam. The driving beam is assumed to be density-modulated. The preliminary modulation of the driving REB is shown to enhance substantially the acceleration efficiency of relativistic electrons of the driven beam. The second section deals with the two-beam acceleration in the vacuum corrugated waveguide. According to this scheme the excitation of electromagnetic waves and acceleration of driven beam electrons by them is accomplished under different Cherenkov resonances between the particles of beams and the corrugated waveguide field. The electromagnetic field in the periodic structure is known to be the superposition of spatial harmonics. With the small depth of the periodic nonuniformity the amplitudes of these harmonics decrease fast with their number increasing. Therefore, if the driving beam is in the Cherenkov resonance with the first spatial harmonic and the driven beam is in resonance with the zero space harmonic then the force accelerating the driven beam would be considerably bigger than the force decelerating the driving beam electrons.

  12. Development of a dual-pulse RF driver for an S-band (= 2856 MHz) RF electron linear accelerator

    NASA Astrophysics Data System (ADS)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Lee, Byung Cheol; Cha, Hyungki; Ha, Jang Ho; Park, Hyung Dal; Lee, Seung Hyun; Kim, Hui Su; Buaphad, Pikad

    2016-04-01

    The radiation equipment research division of Korea Atomic Energy Research Institute has developed a Container Inspection System (CIS) using a Radio Frequency (RF) electron linear accelerator for port security. The primary purpose of the CIS is to detect nuclear materials and explosives, as well country-specific prohibited substances, e.g., smuggled. The CIS consists of a 9/6 MeV dualenergy electron linear accelerator for distinguishing between organic and inorganic materials. The accelerator consists of an electron gun, an RF accelerating structure, an RF driver, a modulator, electromagnets, a cooling system, a X-ray generating target, X-ray collimator, a detector, and a container moving system. The RF driver is an important part of the configuration because it is the RF power source: it supplies the RF power to the accelerating structure. A unique aspect of the RF driver is that it generates dual RF power to generate dual energy (9/6 MeV). The advantage of this RF driver is that it can allow the pulse width to vary and can be used to obtain a wide range of energy output, and pulse repetition rates up to 300 Hz. For this reason, 140 W (5 MW - 9 MeV) and 37 W (3.4 MW - 6 MeV) power outputs are available independently. A high power test for 20 minutes demonstrate that stable dual output powers can be generated. Moreover, the dual power can be applied to the accelerator which has stable accelerator operation. In this paper, the design, fabrication and high power test of the RF driver for the RF electron linear accelerator (linac) are presented.

  13. Analytical validation of accelerator mass spectrometry for pharmaceutical development

    PubMed Central

    Keck, Bradly D; Ognibene, Ted; Vogel, John S

    2011-01-01

    The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of 14C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the 14C label), stable across samples storage conditions for at least 1 year, linear over four orders of magnitude with an analytical range from 0.1 Modern to at least 2000 Modern (instrument specific). Furthermore, accuracy was excellent (between 1 and 3%), while precision expressed as coefficient of variation was between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of 14C, respectively (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with 14C corresponds to 30 fg equivalents. Accelerator mass spectrometry provides a sensitive, accurate and precise method of measuring drug compounds in biological matrices. PMID:21083256

  14. Analytical validation of accelerator mass spectrometry for pharmaceutical development.

    PubMed

    Keck, Bradly D; Ognibene, Ted; Vogel, John S

    2010-03-01

    The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of (14)C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the (14)C label), stable across samples storage conditions for at least 1 year, linear over four orders of magnitude with an analytical range from 0.1 Modern to at least 2000 Modern (instrument specific). Furthermore, accuracy was excellent (between 1 and 3%), while precision expressed as coefficient of variation was between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of (14)C, respectively (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with (14)C corresponds to 30 fg equivalents. Accelerator mass spectrometry provides a sensitive, accurate and precise method of measuring drug compounds in biological matrices.

  15. Flashover lithium ion source development for large pulsed power accelerators

    SciTech Connect

    Bieg, K.W.; Burns, E.J.T.; Gerber, R.A.; Olsen, J.N.; Lamppa, K.P.

    1986-05-01

    The Particle Beam Fusion Accelerator II (PBFA II), a light-ion pulsed power accelerator intended for inertial confinement fusion (ICF) applications, is currently under construction at Sandia National Laboratories. The accelerator will deliver a 30 MV, 5 MA lithium beam from an Applied-B diode to drive an ICF target. The ion source for this diode will require a thin (approx.1 mm), dense (10/sup 16/ cm/sup -2/) anode plasma layer of singly ionized lithium over an anode area of 10/sup 3/ cm/sup 2/. One type of source being investigated is the flashover ion source, which generates the anode plasma via vacuum flashover of a lithium-bearing dielectric material. Experiments with a LiF flashover source on the 0.03 TW Nereus accelerator have shown that contaminant ions account for as much as 70% of the extracted ion beam current. To overcome this, we have explored in-diode cleaning of the externally prepared anode surface by glow discharge cleaning and vacuum baking as well as in-diode preparation of the anode surface by vacuum evaporation of the lithium dielectric. Lithium-bearing dielectric materials which have been investigated include LiF, LiI, LiNO/sub 3/, and Li/sub 3/N. These techniques have resulted in a two to threefold improvement in the extracted lithium ion purity. As a result, a glow-discharge cleaned LiF flashover source will be used for initial pulsed-power testing on PBFA II.

  16. Design and fabrication of a traveling-wave muffin-tin accelerating structure at 90 GHz

    SciTech Connect

    Chou, P.J.; Bowden, G.B.; Copeland, M.R.; Menegat, A.; Siemann, R.H.; Henke, H.

    1997-05-01

    A prototype of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz) was built for research in high gradient acceleration. A traveling-wave design with single input and output feeds was chosen for the prototype which was fabricated by wire electrodischarge machining. Features of the mechanical design for the prototype are described. Design improvements are presented including considerations of cooling and vacuum.

  17. An Update on the DOE Early Career Project on Photonic Band Gap Accelerator Structures

    SciTech Connect

    Simakov, Evgenya I.; Edwards, Randall L.; Haynes, William B.; Madrid, Michael A.; Romero, Frank P.; Tajima, Tsuyoshi; Tuzel, Walter M.; Boulware , Chase H.; Grimm, Terry

    2012-06-07

    We performed fabrication of two SRF PBG resonators at 2.1 GHz and demonstrated their proof-of-principle operation at high gradients. Measured characteristics of the resonators were in good agreement with theoretical predictions. We demonstrated that SRF PBG cavities can be operated at 15 MV/m accelerating gradients. We completed the design and started fabrication of the 16-cell PBG accelerating structure at 11.7 GHz for wakefield testing at AWA.

  18. Flashover lithium ion source development for large pulsed power accelerators

    SciTech Connect

    Bieg, K.W.; Burns, E.J.T.; Gerber, R.A.; Olsen, J.N.; Lamppa, K.P.

    1985-01-01

    PBFA II, a light-ion pulsed power accelerator intended for inertial confinement fusion (ICF) applications, is currently under construction at Sandia National Laboratories. The accelerator will deliver a 30 MV, 5 MA lithium beam from an Applied-B diode to drive an ICF target. The ion source for this diode will require a thin (approx.1 mm), dense (10 W cm S) anode plasma layer of singly-ionized lithium over an anode area of 10T cmS. One type of source being investigated is the flashover ion source, which generates the anode plasma via vacuum flashover of a lithium-bearing dielectric material. Experiments with a LiF flashover source on the 0.03 TW Nereus accelerator have shown that contaminant ions account for as much as 70% of the extracted ion beam current. To overcome this, we have explored in-diode cleaning of the externally-prepared anode surface by glow discharge cleaning and vacuum baking as well as in-diode preparation of the anode surface by vacuum evaporation of the lithium dielectric. Lithium-bearing dielectric materials which have been investigated include LiF, LiI, LiNO3, and Li3N. These techniques have resulted in a two- to three-fold improvement in the extracted lithium ion purity. As a result, a glow-discharge cleaned LiF flashover source will be used for initial pulsed-power testing on PBFA II.

  19. Analysis of Male Pheromones That Accelerate Female Reproductive Organ Development

    PubMed Central

    Flanagan, Kelly A.; Webb, William; Stowers, Lisa

    2011-01-01

    Male odors can influence a female's reproductive physiology. In the mouse, the odor of male urine results in an early onset of female puberty. Several volatile and protein pheromones have previously been reported to each account for this bioactivity. Here we bioassay inbred BALB/cJ females to study pheromone-accelerated uterine growth, a developmental hallmark of puberty. We evaluate the response of wild-type and mutant mice lacking a specialized sensory transduction channel, TrpC2, and find TrpC2 function to be necessary for pheromone-mediated uterine growth. We analyze the relative effectiveness of pheromones previously identified to accelerate puberty through direct bioassay and find none to significantly accelerate uterine growth in BALB/cJ females. Complementary to this analysis, we have devised a strategy of partial purification of the uterine growth bioactivity from male urine and applied it to purify bioactivity from three different laboratory strains. The biochemical characteristics of the active fraction of all three strains are inconsistent with that of previously known pheromones. When directly analyzed, we are unable to detect previously known pheromones in urine fractions that generate uterine growth. Our analysis indicates that pheromones emitted by males to advance female puberty remain to be identified. PMID:21347429

  20. Graduate Student Program in Materials and Engineering Research and Development for Future Accelerators

    SciTech Connect

    Spentzouris, Linda

    2016-07-07

    The objective of the proposal was to develop graduate student training in materials and engineering research relevant to the development of particle accelerators. Many components used in today's accelerators or storage rings are at the limit of performance. The path forward in many cases requires the development of new materials or fabrication techniques, or a novel engineering approach. Often, accelerator-based laboratories find it difficult to get top-level engineers or materials experts with the motivation to work on these problems. The three years of funding provided by this grant was used to support development of accelerator components through a multidisciplinary approach that cut across the disciplinary boundaries of accelerator physics, materials science, and surface chemistry. The following results were achieved: (1) significant scientific results on fabrication of novel photocathodes, (2) application of surface science and superconducting materials expertise to accelerator problems through faculty involvement, (3) development of instrumentation for fabrication and characterization of materials for accelerator components, (4) student involvement with problems at the interface of material science and accelerator physics.

  1. Cornerstones of Completion: State Policy Support for Accelerated, Structured Pathways to College Credentials and Transfer

    ERIC Educational Resources Information Center

    Couturier, Lara K.

    2012-01-01

    In spring 2012, after a year of intensive data analysis and planning, the colleges participating in Completion by Design announced strategies for creating clear, structured routes through college for more students, often referred to as accelerated, structured pathways to completion. These strategies contain elements unique to each college, but all…

  2. Design of RF Feed System for Standing-Wave Accelerator Structures

    SciTech Connect

    Neilson, Jeffrey; Tantawi, Sami; Dolgashev, Valery

    2010-11-04

    We are investigating a standing wave structure with an rf feed to each individual cell. This approach minimizes rf power flow and electromagnetic energy absorbed by an rf breakdown. The objective of this work is a robust high-gradient (above 100 MV/m) X-band accelerator structure.

  3. Frequency Domain Tomography Of Evolving Laser-Plasma Accelerator Structures

    SciTech Connect

    Dong Peng; Reed, Stephen; Kalmykov, Serguei; Shvets, Gennady; Downer, Mike

    2009-01-22

    Frequency Domain Holography (FDH), a technique for visualizing quasistatic objects propagating near the speed of light, has produced 'snapshots' of laser wakefields, but they are averaged over structural variations that occur during propagation through the plasma medium. Here we explore via simulations a generalization of FDH--that we call Frequency Domain Tomography (FDT)--that can potentially record a time sequence of quasistatic snapshots, like the frames of a movie, of the wake structure as it propagates through the plasma. FDT utilizes a several probe-reference pulse pairs that propagate obliquely to the drive pulse and wakefield, along with tomographic reconstruction algorithms similar to those used in medical CAT scans.

  4. Residual acceleration data on IML-1: Development of a data reduction and dissemination plan

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. Iwan D.

    1993-01-01

    The research performed consisted of three stages: (1) identification of sensitive IML-1 experiments and sensitivity ranges by order of magnitude estimates, numerical modeling, and investigator input; (2) research and development towards reduction, supplementation, and dissemination of residual acceleration data; and (3) implementation of the plan on existing acceleration databases.

  5. Jefferson Lab Accelerator Operations Training and Development Program

    SciTech Connect

    Michael A. Epps

    2008-01-23

    The mission of the Jefferson Lab Operations Group is to provide safe and efficient delivery of high quality electron beam for Jefferson Laboratory's nuclear and accelerator physics programs. The Operations staff must be able to setup, transport, maintain, and troubleshoot beam to all three experimental halls in a safe, efficient, and expeditious manner. Due to the nature of shift work, high employee turnover is always as issue. This creates a unique situation where highly trained staff members must quickly be produced and maintained in order to meet the needs of the Laboratory. Some methods used to address this problem will be presented here.

  6. Status of engineering development of CCDTL for accelerator production of tritium

    SciTech Connect

    Wood, R.L.; Billen, J.H.; Hunter, W.T.; Leslie, P.O.; Roybal, R.J.; Sigler, F.E.

    1998-12-31

    The Coupled-Cavity Drift Tube Linac (CCDTL) is a relatively new RF accelerator structure which plays a major role in the APT Low-Energy Linac (LEL) design. Engineering development is pushing ahead on several fronts, including thermal management, fabrication procedures, cavity and coupling slot tuning, high-power prototype fabrication and testing, supports and alignment, vacuum, and provisions for beam diagnostics. Fabrication of the CCDTL Low-Beta Hot Model is nearly complete, and high-power RF tests will commence soon. In 1999, the authors will begin the fabrication of 11 meters of CCDTL to be added to the Low-Energy Demonstration Accelerator. In 2001, it will take the 100 mA beam from 6.7 MeV to 10.05 MeV, producing the world`s most powerful proton beam. The authors are also starting the design of a CCDTL 96 MeV Hot Model to demonstrate cooling of an intermediate-Beta version of the structure. The 14cm-long, 9cm diameter drift tube has roughly 5kW dissipated on it. This all leads to the final mechanical design of the 113m long CCDTL for the APT plant linac.

  7. Challenges to self-acceleration in modified gravity from gravitational waves and large-scale structure

    NASA Astrophysics Data System (ADS)

    Lombriser, Lucas; Lima, Nelson A.

    2017-02-01

    With the advent of gravitational-wave astronomy marked by the aLIGO GW150914 and GW151226 observations, a measurement of the cosmological speed of gravity will likely soon be realised. We show that a confirmation of equality to the speed of light as indicated by indirect Galactic observations will have important consequences for a very large class of alternative explanations of the late-time accelerated expansion of our Universe. It will break the dark degeneracy of self-accelerated Horndeski scalar-tensor theories in the large-scale structure that currently limits a rigorous discrimination between acceleration from modified gravity and from a cosmological constant or dark energy. Signatures of a self-acceleration must then manifest in the linear, unscreened cosmological structure. We describe the minimal modification required for self-acceleration with standard gravitational-wave speed and show that its maximum likelihood yields a 3σ poorer fit to cosmological observations compared to a cosmological constant. Hence, equality between the speeds challenges the concept of cosmic acceleration from a genuine scalar-tensor modification of gravity.

  8. Enhancement of maximum attainable ion energy in the radiation pressure acceleration regime using a guiding structure

    SciTech Connect

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Pegoraro, F.; Leemans, W. P.

    2015-03-13

    Radiation Pressure Acceleration is a highly efficient mechanism of laser driven ion acceleration, with the laser energy almost totally transferrable to the ions in the relativistic regime. There is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. In the case of a tightly focused laser pulses, which are utilized to get the highest intensity, another factor limiting the maximum ion energy comes into play, the transverse expansion of the target. Transverse expansion makes the target transparent for radiation, thus reducing the effectiveness of acceleration. Utilization of an external guiding structure for the accelerating laser pulse may provide a way of compensating for the group velocity and transverse expansion effects.

  9. Enhancement of maximum attainable ion energy in the radiation pressure acceleration regime using a guiding structure

    DOE PAGES

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B.; ...

    2015-03-13

    Radiation Pressure Acceleration is a highly efficient mechanism of laser driven ion acceleration, with the laser energy almost totally transferrable to the ions in the relativistic regime. There is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. In the case of a tightly focused laser pulses, which are utilized to get the highest intensity, another factor limiting the maximum ion energy comes into play, the transverse expansion of the target. Transverse expansion makes the target transparent for radiation, thus reducing the effectiveness of acceleration. Utilization of an external guidingmore » structure for the accelerating laser pulse may provide a way of compensating for the group velocity and transverse expansion effects.« less

  10. USE OF ACOUSTIC EMISSION TO DIAGNOSE BREAKDOWN IN ACCELERATOR RF STRUCTURES

    SciTech Connect

    Nelson, Janice L.

    2003-05-12

    Accelerator structures of a wide variety have been damaged by RF breakdowns. Very little is known about the mechanisms that cause the breakdown and the damage although there has been theoretical work [1,2]. Using an array of ultrasonic acoustic emission sensors we have been able to locate and classify breakdown events more accurately than possible using microwave techniques. Data from the technique has led to improvements in the design of the NLC X-band RF structure. We report results of acoustic emission studies at the DESY TESLA Test Facility and the SLAC NLC Test Accelerator.

  11. Comparison of accelerating structures for the first cavity of the main part of the INR linac

    NASA Astrophysics Data System (ADS)

    Rybakov, I. V.; Kalinin, Y. Z.; Leontev, V. N.; Naboka, A. N.; Paramonov, V. V.; Serov, V. L.; Feschenko, A. V.

    2016-09-01

    For the beam power improvement of the hydrogen-ion INR linac replacement of the first four-section cavity in the main part of linac is required. Existent cavity is realized using DAW structure on 991 MHz operating frequency. The new cavity should at least not lose in parameters to the current structure and essential changes in other linac systems are not wish able. Parameters of accelerating structures possible for such application are compared.

  12. Cosmic microwave background anisotropy from nonlinear structures in accelerating universes

    SciTech Connect

    Sakai, Nobuyuki; Inoue, Kaiki Taro

    2008-09-15

    We study the cosmic microwave background (CMB) anisotropy due to spherically symmetric nonlinear structures in flat universes with dust and a cosmological constant. By modeling a time-evolving spherical compensated void/lump by Lemaitre-Tolman-Bondi spacetimes, we numerically solve the null geodesic equations with the Einstein equations. We find that a nonlinear void redshifts the CMB photons that pass through it regardless of the distance to it. In contrast, a nonlinear lump blueshifts (or redshifts) the CMB photons if it is located near (or sufficiently far from) us. The present analysis comprehensively covers previous works based on a thin-shell approximation and a linear/second-order perturbation method and the effects of shell thickness and full nonlinearity. Our results indicate that, if quasilinear and large (> or approx.100 Mpc) voids/lumps would exist, they could be observed as cold or hot spots with temperature variance > or approx. 10{sup -5} K in the CMB sky.

  13. 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.

  14. Niobium cavity development for the high-energy linac of the rare isotope accelerator

    SciTech Connect

    D. Barni; C. Pagani; P. Pierini; C. Compton; T. Grimm; W. Hartung; H. Podlech; R. York; G. Ciovati; P. Kneisel

    2001-08-01

    The Rare Isotope Accelerator (RIA) is being designed to supply an intense beam of exotic isotopes for nuclear physics research [1]. Superconducting cavities are to be used to accelerate the CW beam of heavy ions to 400 MeV per nucleon, with a beam power of up to 400 kW. Because of the varying velocity of the ion beam along the linac, a number of different types of superconducting structures are needed. The RIA linac will accelerate heavy ions over the same velocity range as the proton linac for the Spallation Neutron Source (SNS). It was decided to use the 6-cell axisymmetric 805 MHz cavities and cryostats of SNS for the downstream portion of the RIA linac, thereby saving the non-recurring development and engineering costs. For additional cost saving, it was decided to extend the SNS multi-cell axisymmetric cavity design to lower velocity, {beta} = v/c = 0.4, using the same cryostats and RF systems. Axisymmetric cavities will thus constitute about three-quarters of RIA's total accelerating voltage, and most of that voltage will be provided by cavities already developed for SNS. The axisymmetric cavities will accelerate the RIA beam from {beta} = 0.4 to {beta} = 0.72. This velocity range can be efficiently covered with two different types of 6-cell cavities, one with a geometric {beta}, {beta}{sub g}, of 0.47, and the other with a {beta}{sub g} of 0.61. The {beta}{sub g} = 0.61 cavity will be of the existing SNS design; some {beta}{sub g} = 0.81 SNS cavities may also be desired at the end of the RIA linac for acceleration of light ions above 400 MeV per nucleon. Prototypes for both {beta}{sub g} = 0.61 and {beta}{sub g} = 0.81 have been fabricated and tested [2]. The {beta}{sub g} = 0.47 cavity is the focus of the present work. The reduction in {beta}{sub g} to 0.47 results in less favourable electromagnetic and mechanical properties, and opens up the possibility of multipacting, but several groups have already designed and prototyped cavities in this range. These

  15. Free-electron laser as a power source for a high-gradient accelerating structure

    SciTech Connect

    Sessler, A.M.

    1982-02-01

    A two beam colliding linac accelerator is proposed in which one beam is intense (approx. = 1KA), of low energy (approx. = MeV), and long (approx. = 100 ns) and provides power at 1 cm wavelength through a free-electron-laser-mechanism to the second beam of a few electrons (approx. = 10/sup 11/), which gain energy at the rate of 250 MeV/m in a high-gradient accelerating structure and hence reach 375 GeV in 1.5 km. The intense beam is given energy by induction units and gains, and losses by radiation, 250 keV/m thus supplying 25 J/m to the accelerating structure. The luminosity, L, of two such linacs would be, at a repetition rate of 1 kHz, L = 4. x 10/sup 32/ cm/sup -2/ s/sup -1/.

  16. Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator.

    PubMed

    He, Z-H; Beaurepaire, B; Nees, J A; Gallé, G; Scott, S A; Pérez, J R Sánchez; Lagally, M G; Krushelnick, K; Thomas, A G R; Faure, J

    2016-11-08

    Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wakefield-accelerated electron bunches for time-resolved electron diffraction measurements of the structural dynamics of single-crystal silicon nano-membranes pumped by an ultrafast laser pulse. In our proof-of-concept study, we resolve the silicon lattice dynamics on a picosecond time scale by deflecting the momentum-time correlated electrons in the diffraction peaks with a static magnetic field to obtain the time-dependent diffraction efficiency. Further improvements may lead to femtosecond temporal resolution, with negligible pump-probe jitter being possible with future laser-wakefield-accelerator ultrafast-electron-diffraction schemes.

  17. Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    He, Z.-H.; Beaurepaire, B.; Nees, J. A.; Gallé, G.; Scott, S. A.; Pérez, J. R. Sánchez; Lagally, M. G.; Krushelnick, K.; Thomas, A. G. R.; Faure, J.

    2016-11-01

    Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wakefield-accelerated electron bunches for time-resolved electron diffraction measurements of the structural dynamics of single-crystal silicon nano-membranes pumped by an ultrafast laser pulse. In our proof-of-concept study, we resolve the silicon lattice dynamics on a picosecond time scale by deflecting the momentum-time correlated electrons in the diffraction peaks with a static magnetic field to obtain the time-dependent diffraction efficiency. Further improvements may lead to femtosecond temporal resolution, with negligible pump-probe jitter being possible with future laser-wakefield-accelerator ultrafast-electron-diffraction schemes.

  18. 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.

  19. Interaction of an Ultrarelativistic Electron Bunch Train with a W-Band Accelerating Structure: High Power and High Gradient.

    PubMed

    Wang, D; Antipov, S; Jing, C; Power, J G; Conde, M; Wisniewski, E; Liu, W; Qiu, J; Ha, G; Dolgashev, V; Tang, C; Gai, W

    2016-02-05

    Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to the interference of the wakefields from the two bunches, was measured as a function of bunch separation. Measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.

  20. Interaction of an Ultrarelativistic Electron Bunch Train with a W -Band Accelerating Structure: High Power and High Gradient

    NASA Astrophysics Data System (ADS)

    Wang, D.; Antipov, S.; Jing, C.; Power, J. G.; Conde, M.; Wisniewski, E.; Liu, W.; Qiu, J.; Ha, G.; Dolgashev, V.; Tang, C.; Gai, W.

    2016-02-01

    Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to the interference of the wakefields from the two bunches, was measured as a function of bunch separation. Measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.

  1. Interaction of an ultrarelativistic electron bunch train with a W-band accelerating structure: High power and high gradient

    DOE PAGES

    Wang, D.; Antipov, S.; Jing, C.; ...

    2016-02-05

    Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to themore » interference of the wakefields from the two bunches, was measured as a function of bunch separation. As a result, measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.« less

  2. Interaction of an ultrarelativistic electron bunch train with a W-band accelerating structure: High power and high gradient

    SciTech Connect

    Wang, D.; Antipov, S.; Jing, C.; Power, J. G.; Conde, M.; Wisniewski, E.; Liu, W.; Qiu, J.; Ha, G.; Dolgashev, V.; Tang, C.; Gai, W.

    2016-02-05

    Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to the interference of the wakefields from the two bunches, was measured as a function of bunch separation. As a result, measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.

  3. EuCARD2: enhanced accelerator research and development in Europe

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2013-10-01

    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. EuCARD2 is an European research project which will be realized during 2013-2017 inside the EC FP7 framework. The project concerns the development and coordination of European Accelerator Research and Development. The project is particularly important, to a number of domestic laboratories, due to some plans to build large accelerator infrastructure in Poland. Large accelerator infrastructure of fundamental and applied research character stimulates around it the development and industrial applications as well as biomedical of advanced accelerators, material research and engineering, cryo-technology, mechatronics, robotics, and in particular electronics - like networked measurement and control systems, sensors, computer systems, automation and control systems. The paper presents a digest of the European project EuCARD2 which is Enhanced European Coordination for Accelerator Research and Development. The paper presents a digest of the research results and assumptions in the domain of accelerator science and technology in Europe, shown during the final fourth annual meeting of the EuCARD - European Coordination of Accelerator R&D, and the kick-off meeting of the EuCARD2. There are debated a few basic groups of accelerator systems components 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, high field magnets, superconducting cavities, novel beam collimators, etc. The paper bases on the following materials: Internet and Intranet documents combined with EuCARD2, Description of Work FP7 EuCARD-2 DoW-312453, 2013-02-13, and discussions and preparatory materials worked on by Eucard-2 initiators.

  4. X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment

    SciTech Connect

    Marsh, Roark A.; Shapiro, Michael A.; Temkin, Richard J.; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC

    2012-06-11

    In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.

  5. Challenging developments in three decades of accelerator mass spectrometry at ETH: from large particle accelerators to table size instruments.

    PubMed

    Suter, Martin

    2010-01-01

    Accelerator mass spectrometry (AMS) was invented for the detection of radiocarbon at natural isotopic concentrations (10(-12) to 10(-15)) more than 30 years ago. Meanwhile this method has also been applied for the analysis of many other long-lived radioisotopes, which are found at very low concentrations. The first investigations were made at large tandem accelerators originally built for nuclear physics research and operating at voltages of 6-12 MV. Today dedicated instruments are mostly used for AMS, which are optimized for associated applications. In the past 15 years, a new generation of much smaller instruments has been developed. For many years it was believed that accelerators with voltages of 2 MV or higher are needed to eliminate the molecular interferences. At these energies the ions are predominantly stripped to charge state 3+, thereby removing the binding electrons of the molecules. In contrast, the new compact facilities use 1+ or 2+ ions. In this case the molecular destruction process is based on molecule-atom collisions in the gas cell. The cross sections for this destruction are sufficiently large that the intensity of molecular components such as (12)CH(2) and (13)CH can be reduced by 10 orders of magnitude. These new facilities can be built much smaller due to the lower energies. Universal instruments providing analysis for many isotopes over the whole range of periodic table have a space requirement of about 4 x 6 m(2); dedicated radiocarbon facilities based on a 200 kV accelerator have a footprint of about 2.5 x 3 m(2). This smallest category of instruments use special technologies: The high voltage terminal with the gas stripper canal is vacuum insulated and the gas is pumped to ground potential through a ceramic pipe. A conventional 200 kV power supply provides the terminal voltage from outside. A review of this new generation of compact AMS facilities is given. Design considerations and performance of these new instruments will be presented

  6. Proposal for a study of laser acceleration of electrons using micrograting structures at ATF (Phase 1)

    SciTech Connect

    Chen, W.; Claus, J.; Fernow, R.C.; Fischer, J.; Gallardo, J.C.; Kirk, H.G.; Kramer, H.; Li, Z.; Palmer, R.B.; Rogers, J.; Shrinvasan-Rao, T.; Tsang, T.; Ulc, S.; Veligdan, J.; Warren, J.; Bigio, I.; Kurnit, N.; Shimada, T.; Wang, X.; McDonald, K.T.; Russell, D.P.; Los Alamos National Lab., NM; Princeton Univ., NJ; California Univ., Los Angeles, CA )

    1989-10-29

    We propose to investigate new methods of particle acceleration using a short-pulse CO{sub 2} laser as the power source and grating-like structures as accelerator cavities''. Phase I of this program is intended to demonstrate the principle of the method. We will focus the laser light to a 3 mm line on the surface of the microstructure. The structure is used to transform the electric field pattern of the incoming transversely polarized laser beam to a mode which has a component along the electron beam direction in the vicinity of the surface. With 6 mJ of laser energy and a 6 ps pulse length, the electric field in the spot will be around 1 GV/m. The electron beam from the Brookhaven Accelerator Test Facility (ATF) will be focused transversely within the few micron transverse dimension of the microstructure. The maximum expected acceleration for a 1 GV/m field and a 3 mm acceleration length is 3 MeV. 17 refs., 11 figs., 2 tabs.

  7. Accelerated safety analyses - structural analyses Phase I - structural sensitivity evaluation of single- and double-shell waste storage tanks

    SciTech Connect

    Becker, D.L.

    1994-11-01

    Accelerated Safety Analyses - Phase I (ASA-Phase I) have been conducted to assess the appropriateness of existing tank farm operational controls and/or limits as now stipulated in the Operational Safety Requirements (OSRs) and Operating Specification Documents, and to establish a technical basis for the waste tank operating safety envelope. Structural sensitivity analyses were performed to assess the response of the different waste tank configurations to variations in loading conditions, uncertainties in loading parameters, and uncertainties in material characteristics. Extensive documentation of the sensitivity analyses conducted and results obtained are provided in the detailed ASA-Phase I report, Structural Sensitivity Evaluation of Single- and Double-Shell Waste Tanks for Accelerated Safety Analysis - Phase I. This document provides a summary of the accelerated safety analyses sensitivity evaluations and the resulting findings.

  8. Damped accelerator structures for future linear e/sup/plus minus// colliders

    SciTech Connect

    Deruyter, H.; Hoag, H.A.; Lisin, A.V.; Loew, G.A.; Palmer, R.B.; Paterson, J.M.; Rago, C.E.; Wang, J.W.

    1989-03-01

    This paper describes preliminary work on accelerator structures for future TeV linear colliders which use trains of e/sup +-/ bunches to reach the required luminosity. These bunch trains, if not perfectly aligned with respect to the accelerator axis, induce transverse wake field modes into the structure. Unless they are sufficiently damped, these modes cause cummulative beam deflections and emittance growth. The envisaged structures, originally proposed by R. B. Palmer, are disk-loaded waveguides in which the disks are slotted radially into quadrants. Wake field energy is coupled via the slots and double-ridged waveguides into a lossy region which is external to the accelerator structure. The requirement is that the Q of the HEM/sub 11/ mode be reduced to a value of less than 30. The work done so far includes MAFIA code computations and low power rf measurements to study the fields. A four-cavity 2..pi../3 mode standing-wave structure has been built to find whether the slots lower the electric breakdown thresholds below those reached with conventional disk-loaded structures. We set out to assess the microwave properties of the structure and the problems which might be encountered in fabricating it. 4 refs., 7 figs.

  9. Rapid analysis of scattering from periodic dielectric structures using accelerated Cartesian expansions

    SciTech Connect

    Baczewski, Andrew David; Miller, Nicholas C.; Shanker, Balasubramaniam

    2012-03-22

    Here, the analysis of fields in periodic dielectric structures arise in numerous applications of recent interest, ranging from photonic bandgap structures and plasmonically active nanostructures to metamaterials. To achieve an accurate representation of the fields in these structures using numerical methods, dense spatial discretization is required. This, in turn, affects the cost of analysis, particularly for integral-equation-based methods, for which traditional iterative methods require Ο(Ν2) operations, Ν being the number of spatial degrees of freedom. In this paper, we introduce a method for the rapid solution of volumetric electric field integral equations used in the analysis of doubly periodic dielectric structures. The crux of our method is the accelerated Cartesian expansion algorithm, which is used to evaluate the requisite potentials in Ο(Ν) cost. Results are provided that corroborate our claims of acceleration without compromising accuracy, as well as the application of our method to a number of compelling photonics applications.

  10. Structural Seal Development

    NASA Technical Reports Server (NTRS)

    DeMange, Jeff

    2002-01-01

    NASA currently has aggressive goals for the development of the next generations of Reusable Launch Vehicles (RLV). Many of the goals center around significantly reducing the time and cost of deployment (including payload) for these spacecraft, as well as substantially increasing the safety of the crew and hardware. A core component in the design of these next generation spacecraft is the propulsion system. Many concepts are currently being evaluated including Rocket Based Combined Cycle (RBCC) and Turbine Based Combined Cycle (TBCC) engine technologies, shown.

  11. An accelerated stochastic vortex structure method for particle collision and agglomeration in homogeneous turbulence

    NASA Astrophysics Data System (ADS)

    Dizaji, Farzad F.; Marshall, Jeffrey S.

    2016-11-01

    Modeling the response of interacting particles, droplets, or bubbles to subgrid-scale fluctuations in turbulent flows is a long-standing challenge in multiphase flow simulations using the Reynolds-Averaged Navier-Stokes approach. The problem also arises for large-eddy simulation for sufficiently small values of the Kolmogorov-scale particle Stokes number. This paper expands on a recently proposed stochastic vortex structure (SVS) method for modeling of turbulence fluctuations for colliding or otherwise interacting particles. An accelerated version of the SVS method was developed using the fast multipole expansion and local Taylor expansion approach, which reduces computation speed by two orders of magnitude compared to the original SVS method. Detailed comparisons are presented showing close agreement of the energy spectrum and probability density functions of various fields between the SVS computational model, direct numerical simulation (DNS) results, and various theoretical and experimental results found in the literature. Results of the SVS method for particle collision rate and related measures of particle interaction exhibit excellent agreement with DNS predictions for homogeneous turbulent flows. The SVS method was also used with adhesive particles to simulate formation of particle agglomerates with different values of the particle Stokes and adhesion numbers, and various measures of the agglomerate structure are compared to the DNS results.

  12. Guided post-acceleration of laser-driven ions by a miniature modular structure

    PubMed Central

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-01-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m−1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications. PMID:27089200

  13. Developments in laser wakefield accelerators: From single-stage to two-stage

    NASA Astrophysics Data System (ADS)

    Li, Wen-Tao; Wang, Wen-Tao; Liu, Jian-Sheng; Wang, Cheng; Zhang, Zhi-Jun; Qi, Rong; Yu, Chang-Hai; Li, Ru-Xin; Xu, Zhi-Zhan

    2015-01-01

    Laser wakefield accelerators (LWFAs) are compact accelerators which can produce femtosecond high-energy electron beams on a much smaller scale than the conventional radiofrequency accelerators. It is attributed to their high acceleration gradient which is about 3 orders of magnitude larger than the traditional ones. The past decade has witnessed the major breakthroughs and progress in developing the laser wakfield accelerators. To achieve the LWFAs suitable for applications, more and more attention has been paid to optimize the LWFAs for high-quality electron beams. A single-staged LWFA does not favor generating controllable electron beams beyond 1 GeV since electron injection and acceleration are coupled and cannot be independently controlled. Staged LWFAs provide a promising route to overcome this disadvantage by decoupling injection from acceleration and thus the electron-beam quality as well as the stability can be greatly improved. This paper provides an overview of the physical conceptions of the LWFA, as well as the major breakthroughs and progress in developing LWFAs from single-stage to two-stage LWFAs. Project supported by the National Natural Science Foundation of China (Grant Nos. 11127901, 11425418, and 61221064), the National Basic Research Program of China (Grant No. 2011CB808100), and the Science and Technology Talent Project of Shanghai City, China (Grant Nos. 12XD1405200 and 12ZR1451700).

  14. Group living accelerates bed bug (Hemiptera: Cimicidae) development.

    PubMed

    Saenz, Virna L; Santangelo, Richard G; Vargo, Edward L; Schal, Coby

    2014-01-01

    For many insect species, group living provides physiological and behavioral benefits, including faster development. Bed bugs (Cimex lectularius L.) live in aggregations composed of eggs, nymphs, and adults of various ages. Our aim was to determine whether bed bug nymphs reared in groups develop faster than solitary nymphs. We reared first instars either in isolation or in groups from hatching to adult emergence and recorded their development time. In addition, we investigated the effects of group housing on same-age nymphs versus nymphs reared with adults. Nymphal development was 2.2 d faster in grouped nymphs than in solitary-housed nymphs, representing 7.3% faster overall development. However, this grouping effect did not appear to be influenced by group composition. Thus, similar to other gregarious insect species, nymph development in bed bugs is faster in aggregations than in isolation.

  15. Developments and applications of accelerator system at the Wakasa Wan Energy Research Center

    NASA Astrophysics Data System (ADS)

    Hatori, S.; Kurita, T.; Hayashi, Y.; Yamada, M.; Yamada, H.; Mori, J.; Hamachi, H.; Kimura, S.; Shimoda, T.; Hiroto, M.; Hashimoto, T.; Shimada, M.; Yamamoto, H.; Ohtani, N.; Yasuda, K.; Ishigami, R.; Sasase, M.; Ito, Y.; Hatashita, M.; Takagi, K.; Kume, K.; Fukuda, S.; Yokohama, N.; Kagiya, G.; Fukumoto, S.; Kondo, M.

    2005-12-01

    At the Wakasa Wan Energy Research Center (WERC), an accelerator system with a 5 MV tandem accelerator and a 200 MeV proton synchrotron is used for ion beam analyses and irradiation experiments. The study of cancer therapy with a proton beam is also performed. Therefore, the stable operation and efficient sharing of beam time of the system are required, based on the treatment standard. Recent developments and the operation status of the system put stress on the tandem accelerator operation, magnifying the problems.

  16. Accelerated Development of a High Field Single Electron Spin Microscope

    DTIC Science & Technology

    2007-11-02

    software has been developed for that. (3) Satisfactory millimeter wave excitations have been achieved with the developed mm wave power amplifiers and strip...incoherent SESM signal – a prelude to handle quantum information. Today we can report the successful solution of all these problems, although the...been achieved with the developed mm wave power amplifiers and strip-line resonators. At the time of writing this report the SESM construction is

  17. Statistical model for field emitter activation on metallic surfaces used in high-gradient accelerating structures

    NASA Astrophysics Data System (ADS)

    Lagotzky, S.; Müller, G.

    2016-01-01

    Both super- and normal-conducting high-gradient linear accelerators are limited by enhanced field emission (EFE) in the accelerating structures, e.g. due to power loss or ignition of discharges. We discuss the dependence of the number density of typical emitters, i.e. particulates and surface defects, on the electric field level at which they are activated for naturally oxidized metallic surfaces. This activation is explained by the transition of a metal-insulator interface into geometric features that enhance the EFE process. A statistical model is successfully compared to systematic studies of niobium and copper relevant for recent and future linear accelerators. Our results show that the achievable surface quality of Nb might be sufficient for the suppression of EFE in the superconducting accelerating structures for the actual European XFEL but not for the planned International Linear Collider. Moreover, some effort will be required to reduce EFE and thus the breakdown rate of the normal conducting Cu structures for the Compact Linear Collider.

  18. Laboratory selection for an accelerated mosquito sexual development rate

    PubMed Central

    2011-01-01

    accelerated sexual maturation when compared with the wild strain. This outcome demonstrates the kinds of selection that can be expected during insect colonization and maintenance, particularly when generations are non-overlapping and similar-age males must compete for mates. PMID:21595988

  19. Accelerated development of Zr-containing new generation ferritic steels for advanced nuclear reactors

    SciTech Connect

    Tan, Lizhen; Yang, Ying; Sridharan, K.

    2015-12-01

    The mission of the Nuclear Energy Enabling Technologies (NEET) program is to develop crosscutting technologies for nuclear energy applications. Advanced structural materials with superior performance at elevated temperatures are always desired for nuclear reactors, which can improve reactor economics, safety margins, and design flexibility. They benefit not only new reactors, including advanced light water reactors (LWRs) and fast reactors such as the sodium-cooled fast reactor (SFR) that is primarily designed for management of high-level wastes, but also life extension of the existing fleet when component exchange is needed. Developing and utilizing the modern materials science tools (experimental, theoretical, and computational tools) is an important path to more efficient alloy development and process optimization. The ultimate goal of this project is, with the aid of computational modeling tools, to accelerate the development of Zr-bearing ferritic alloys that can be fabricated using conventional steelmaking methods. The new alloys are expected to have superior high-temperature creep performance and excellent radiation resistance as compared to Grade 91. The designed alloys were fabricated using arc-melting and drop-casting, followed by hot rolling and conventional heat treatments. Comprehensive experimental studies have been conducted on the developed alloys to evaluate their hardness, tensile properties, creep resistance, Charpy impact toughness, and aging resistance, as well as resistance to proton and heavy ion (Fe2+) irradiation.

  20. Accelerating the Development of Adaptive Performance: Validating the Think Like a Commander Training

    DTIC Science & Technology

    2007-02-01

    U.S. Army Research Institute for the Behavioral and Social Sciences Research Report 1868 Accelerating the Development of Adaptive Performance...REPORT TYPE 3. DATES COVERED (from... to) February 2007 Final March 2005 to March 2006 4. TITLE AND SUBTITLE 5a. CONTRACT OR GRANT NUMBER Accelerating ...deliberate training methods may be more effective and efficient than live, virtual, or constructive experiential learning environments. 15. SUBJECT TERMS

  1. Particle Acceleration Affected by the Evolving Velocity Structures in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Tsubouchi, K.

    2015-12-01

    It is accepted that high-energy particles are efficiently generated during their crossing of shocks in space, where the diffusive shock acceleration is the most standard process to explain the observed energy spectrum beyond the order of a gigaelectronvolt. In contrast, recent spacecraft observations have shown different characteristics in a lower energy range (a kilo- to megaelectronvolt): particles in the heliosphere have a power-law spectrum in particle speed with a spectral index of -5, which is commonly found in any solar wind conditions. This is a puzzling result that the shocks are not a necessary element responsible for accelerating particles. The alternative mechanism, a pump acceleration, is proposed where particles are accelerated in a region containing large-scale compressions and expansions (e.g., Fisk and Gloeckler, JGR 2014). In the present study, we elucidate the validity of this mechanism by performing hybrid simulations to investigate the particle, particularly pickup ions, dynamics in various situations of non-uniform velocity field, such as a simple fast/slow flow interaction, sinusoidal structures, or random profiles, and to compare the velocity spectrum of suprathermal particles in each case. We also study the scale dependence of acceleration processes by comparing the spectrum of the energetic H+, He+, and O+.

  2. Development of integrated superconducting quadrupole doublet modules for operation in the SIS100 accelerator

    NASA Astrophysics Data System (ADS)

    Meier, J.; Bleile, A.; Ceballos Velasco, J.; Fischer, E.; Hess, G.; Macavei, J.; Spiller, P.

    2015-12-01

    The FAIR project (Facility for Antiproton and Ion Research) evolves and builds an international accelerator- and experimental facility for basic research activities in various fields of modern physics. Within the course of this project, integrated quadrupole doublet modules are in development. The quadrupole doublet modules provide a pair of superconducting main quadrupoles (focusing and defocusing), corrector magnets, cryogenic collimators and beam position monitors as integrated sets of ion-optical elements. Furthermore LHe cooled beam pipes and vacuum cold-warm transitions are used as ultra-high vacuum components for beam transportation. Superconducting bus bars are used for 13 kA current supply of the main quadrupole magnets. All components are integrated as one common cold mass into one cryostat. High temperature super conductor local current leads will be applied for the low current supply of corrector magnets. The quadrupole doublet modules will be operated in the SIS100 heavy ion accelerator, the core component of the FAIR project. A first version of a corrector magnet has already been manufactured at the Joint Institute for Nuclear Research (JINR), Russia, and is now ready for testing. The ion-optical lattice structure of SIS100 requires multiple configurations of named components. Eleven different configurations, organized in four categories, provide the required quadrupole doublet module setups. The high integration level of multiple ion-optical, mechanical and cryogenic functions, based on requirements of operation safety, is leading towards a sophisticated mechanical structure and cooling solution, to satisfy the demanding requirements on position preservation during thermal cycling. The mechanical and cryogenic design solutions will be discussed.

  3. Wire Measurement of Impedance of an X-Band Accelerating Structure

    SciTech Connect

    Baboi, N

    2004-09-02

    Several tens of thousands of accelerator structures will be needed for the next generation of normal conducting linear colliders known as the GLC/NLC (Global Linear Collider/Next Linear Collider). To prevent the beam being driven into a disruptive BBU (Beam Break-Up) mode or at the very least, the emittance being significantly diluted, it is important to damp down the wakefield left by driving bunches to a manageable level. Manufacturing errors and errors in design need to be measured and compared with prediction. In this paper a bench-top method of measuring transverse impedances in X-band accelerating structures is described. Utilizing an off-axis wire the S parameters are measured and converted to impedance. Measurements in a damped and detuned structure built for GLC/NLC are presented and the results are discussed.

  4. Diamond field emitter array cathodes and possibilities for employing additive manufacturing for dielectric laser accelerating structures

    SciTech Connect

    Simakov, Evgenya Ivanovna; Andrews, Heather Lynn; Herman, Matthew Joseph; Hubbard, Kevin Mark; Weis, Eric

    2016-09-20

    These are slides for a presentation at Stanford University. The outline is as follows: Motivation: customers for compact accelerators, LANL's technologies for laser acceleration, DFEA cathodes, and additive manufacturing of micron-size structures. Among the stated conclusions are the following: preliminary study identified DFEA cathodes as promising sources for DLAs--high beam current and small emittance; additive manufacturing with Nanoscribe Professional GT can produce structures with the right scale features for a DLA operating at micron wavelengths (fabrication tolerances need to be studied, DLAs require new materials). Future plans include DLA experiment with a beam produced by the DFEA cathode with field emission, demonstration of photoemission from DFEAs, and new structures to print and test.

  5. Developing the Systems Engineering Experience Accelerator (SEEA) Prototype and Roadmap

    DTIC Science & Technology

    2012-10-24

    Figure 1: Notional Diagram of the SEEA Prototype Simulator .......................................... 1 Figure 2: A Day in the Life of a PSE ...and Program Systems Engineer ( PSE ) competency model, known as the SPRDE-SE/ PSE . 2. Developing and maturing systems thinking skills. 3. Developing...mental templates which can be applied to similar future situations Figure 2: A Day in the Life of a PSE UNCLASSIFIED Contract Number: H98230

  6. New science-based endpoints to accelerate oncology drug development.

    PubMed

    Kelloff, Gary J; Sigman, Caroline C

    2005-03-01

    Although several new oncology drugs have reached the market, more than 80% of drugs for all indications entering clinical development do not get marketing approval, with many failing late in development often in Phase III trials, because of unexpected safety issues or difficulty determining efficacy, including confounded outcomes. These factors contribute to the high costs of oncology drug development and clearly show the need for faster, more cost-effective strategies for evaluating oncology drugs and better definition of patients who will benefit from treatment. Remarkable advances in the understanding of neoplastic progression at the cellular and molecular levels have spurred the discovery of molecularly targeted drugs. This progress along with advances in imaging and bioassay technologies are the basis for describing and evaluating new biomarker endpoints as well as for defining other biomarkers for identifying patient populations, potential toxicity, and providing evidence of drug effect and efficacy. Definitions and classifications of these biomarkers for use in oncology drug development are presented in this paper. Science-based and practical criteria for validating biomarkers have been developed including considerations of mechanistic plausibility, available methods and technology, and clinical feasibility. New promising tools for measuring biomarkers have also been developed and are based on genomics and proteomics, direct visualisation by microscopy (e.g., confocal microscopy and computer-assisted image analysis of cellular features), nanotechnologies, and direct and remote imaging (e.g., fluorescence endoscopy and anatomical, functional and molecular imaging techniques). The identification and evaluation of potential surrogate endpoints and other biomarkers require access to and analysis of large amounts of data, new technologies and extensive research resources. Further, there is a requirement for a convergence of research, regulatory and drug developer

  7. Development and initial operating characteristics of the 20 megawatt linear plasma accelerator facility

    NASA Technical Reports Server (NTRS)

    Carter, A. F.; Weaver, W. R.; Mcfarland, D. R.; Wood, G. P.

    1971-01-01

    A 20-megawatt linear plasma accelerator facility, a steady flow, Faraday-type plasma accelerator facility for high velocity aerodynamic testing, was constructed, developed, and brought to an operational status. The accelerator has a 63.5-mm-square and 0.5-meter-long channel and utilizes nitrogen-seeded with 2 % mole fraction of cesium vapor. Modification of the original accelerator design characteristics and the improvements necessary to make the arc heater a suitable plasma source are described. The measured accelerator electrode current distribution and the electrode-wall potential distributions are given. The computed and the measured values are in good agreement. Measured pitot pressure indicates that an accelerator exit velocity of 9.2 km/sec, is obtained with 30 of the 36 electrode pairs powered and corresponds to a velocity increase to about 2 1/4 times the computed entrance velocity. The computed stagnation enthalpy at the accelerator exit is 92 MJ/kg, and the mass density corresponds to an altitude of about 58 km. The 92 MJ/kg stagnation enthalpy corresponds to a kinetic energy content at low temperature equivalent to a velocity of 13.6 km/sec.

  8. Sustainable Energy in Remote Indonesian Grids. Accelerating Project Development

    SciTech Connect

    Hirsch, Brian; Burman, Kari; Davidson, Carolyn; Elchinger, Michael; Hardison, R.; Karsiwulan, D.; Castermans, B.

    2015-06-30

    Sustainable Energy for Remote Indonesian Grids (SERIG) is a U.S. Department of Energy (DOE) funded initiative to support Indonesia’s efforts to develop clean energy and increase access to electricity in remote locations throughout the country. With DOE support, the SERIG implementation team consists of the National Renewable Energy Laboratory (NREL) and Winrock International’s Jakarta, Indonesia office. Through technical assistance that includes techno-economic feasibility evaluation for selected projects, government-to-government coordination, infrastructure assessment, stakeholder outreach, and policy analysis, SERIG seeks to provide opportunities for individual project development and a collective framework for national replication office.

  9. Probabilistic Structural Analysis Theory Development

    NASA Technical Reports Server (NTRS)

    Burnside, O. H.

    1985-01-01

    The objective of the Probabilistic Structural Analysis Methods (PSAM) project is to develop analysis techniques and computer programs for predicting the probabilistic response of critical structural components for current and future space propulsion systems. This technology will play a central role in establishing system performance and durability. The first year's technical activity is concentrating on probabilistic finite element formulation strategy and code development. Work is also in progress to survey critical materials and space shuttle mian engine components. The probabilistic finite element computer program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) is being developed. The final probabilistic code will have, in the general case, the capability of performing nonlinear dynamic of stochastic structures. It is the goal of the approximate methods effort to increase problem solving efficiency relative to finite element methods by using energy methods to generate trial solutions which satisfy the structural boundary conditions. These approximate methods will be less computer intensive relative to the finite element approach.

  10. Fast Track Teaching: Beginning the Experiment in Accelerated Leadership Development

    ERIC Educational Resources Information Center

    Churches, Richard; Hutchinson, Geraldine; Jones, Jeff

    2009-01-01

    This article provides an overview of the development of the Fast Track teaching programme and personalised nature of the training and support that has been delivered. Fast Track teacher promotion rates are compared to national statistics demonstrating significant progression for certain groups, particularly women. (Contains 3 tables and 3 figures.)

  11. Follicle-stimulating hormone accelerates mouse oocyte development in vivo.

    PubMed

    Demeestere, Isabelle; Streiff, Agathe K; Suzuki, João; Al-Khabouri, Shaima; Mahrous, Enas; Tan, Seang Lin; Clarke, Hugh J

    2012-07-01

    During folliculogenesis, oocytes grow and acquire developmental competence in a mutually dependent relationship with their adjacent somatic cells. Follicle-stimulating hormone (FSH) plays an essential and well-established role in the differentiation of somatic follicular cells, but its function in the development of the oocyte has still not been elucidated. We report here that oocytes of Fshb(-/-) mice, which cannot produce FSH, grow at the same rate and reach the same size as those of wild-type mice. Consistent with this observation, the granulosa cells of Fshb(-/-) mice express the normal quantity of mRNA encoding Kit ligand, which has been implicated in oocyte growth. Oocytes of Fshb(-/-) mice also accumulate normal quantities of cyclin B1 and CDK1 proteins and mitochondrial DNA. Moreover, they acquire the ability to complete meiotic maturation in vitro and undergo transition from non-surrounded nucleolus to surrounded nucleolus. However, these events of late oocyte development are significantly delayed. Following in vitro maturation and fertilization, only a small number of embryos derived from oocytes of Fshb(-/-) mice reach the blastocyst stage. Administration of equine chorionic gonadotropin, which provides FSH activity, 48 h before in vitro maturation increases the number of blastocysts obtained subsequently. These results indicate that FSH is not absolutely required for oocyte development in vivo but that this process occurs more rapidly in its presence. We suggest that FSH may coordinate the development of the germline and somatic compartments of the follicle, ensuring that ovulation releases a developmentally competent egg.

  12. Fast economic development accelerates biological invasions in China.

    PubMed

    Lin, Wen; Zhou, Guofa; Cheng, Xinyue; Xu, Rumei

    2007-11-21

    Increasing levels of global trade and intercontinental travel have been cited as the major causes of biological invasion. However, indirect factors such as economic development that affect the intensity of invasion have not been quantitatively explored. Herein, using principal factor analysis, we investigated the relationship between biological invasion and economic development together with climatic information for China from the 1970s to present. We demonstrate that the increase in biological invasion is coincident with the rapid economic development that has occurred in China over the past three decades. The results indicate that the geographic prevalence of invasive species varies substantially on the provincial scale, but can be surprisingly well predicted using the combination of economic development (R(2) = 0.378) and climatic factors (R(2) = 0.347). Economic factors are proven to be at least equal to if not more determinant of the occurrence of invasive species than climatic factors. International travel and trade are shown to have played a less significant role in accounting for the intensity of biological invasion in China. Our results demonstrate that more attention should be paid to economic factors to improve the understanding, prediction and management of biological invasions.

  13. Accelerated renal disease is associated with the development of metabolic syndrome in a glucolipotoxic mouse model

    PubMed Central

    Martínez-García, Cristina; Izquierdo, Adriana; Velagapudi, Vidya; Vivas, Yurena; Velasco, Ismael; Campbell, Mark; Burling, Keith; Cava, Fernando; Ros, Manuel; Orešič, Matej; Vidal-Puig, Antonio; Medina-Gomez, Gema

    2012-01-01

    SUMMARY Individuals with metabolic syndrome are at high risk of developing chronic kidney disease (CKD) through unclear pathogenic mechanisms. Obesity and diabetes are known to induce glucolipotoxic effects in metabolically relevant organs. However, the pathogenic role of glucolipotoxicity in the aetiology of diabetic nephropathy is debated. We generated a murine model, the POKO mouse, obtained by crossing the peroxisome proliferator-activated receptor gamma 2 (PPARγ2) knockout (KO) mouse into a genetically obese ob/ob background. We have previously shown that the POKO mice showed: hyperphagia, insulin resistance, hyperglycaemia and dyslipidaemia as early as 4 weeks of age, and developed a complete loss of normal β-cell function by 16 weeks of age. Metabolic phenotyping of the POKO model has led to investigation of the structural and functional changes in the kidney and changes in blood pressure in these mice. Here we demonstrate that the POKO mouse is a model of renal disease that is accelerated by high levels of glucose and lipid accumulation. Similar to ob/ob mice, at 4 weeks of age these animals exhibited an increased urinary albumin:creatinine ratio and significantly increased blood pressure, but in contrast showed a significant increase in the renal hypertrophy index and an associated increase in p27Kip1 expression compared with their obese littermates. Moreover, at 4 weeks of age POKO mice showed insulin resistance, an alteration of lipid metabolism and glomeruli damage associated with increased transforming growth factor beta (TGFβ) and parathyroid hormone-related protein (PTHrP) expression. At this age, levels of proinflammatory molecules, such as monocyte chemoattractant protein-1 (MCP-1), and fibrotic factors were also increased at the glomerular level compared with levels in ob/ob mice. At 12 weeks of age, renal damage was fully established. These data suggest an accelerated lesion through glucolipotoxic effects in the renal pathogenesis in POKO mice

  14. Evolution of structure and properties of VVER-1000 RPV steels under accelerated irradiation up to beyond design fluences

    NASA Astrophysics Data System (ADS)

    Gurovich, B.; Kuleshova, E.; Shtrombakh, Ya.; Fedotova, S.; Maltsev, D.; Frolov, A.; Zabusov, O.; Erak, D.; Zhurko, D.

    2015-01-01

    In this paper comprehensive studies of structure and properties of VVER-1000 RPV steels after the accelerated irradiation to fluences corresponding to extended lifetime up to 60 years or more as well as comparative studies of materials irradiated with different fluxes were carried out. The significant flux effect is confirmed for the weld metal (nickel concentration ⩾1.35%) which is mainly due to development of reversible temper brittleness. The rate of radiation embrittlement of VVER-1000 RPV steels under operation up to 60 years and more (based on the results of accelerated irradiation considering flux effect for weld metal) is expected not to differ significantly from the observed rate under irradiation within surveillance specimens.

  15. Computational Tools for Accelerating Carbon Capture Process Development

    SciTech Connect

    Miller, David

    2013-01-01

    The goals of the work reported are: to develop new computational tools and models to enable industry to more rapidly develop and deploy new advanced energy technologies; to demonstrate the capabilities of the CCSI Toolset on non-proprietary case studies; and to deploy the CCSI Toolset to industry. Challenges of simulating carbon capture (and other) processes include: dealing with multiple scales (particle, device, and whole process scales); integration across scales; verification, validation, and uncertainty; and decision support. The tools cover: risk analysis and decision making; validated, high-fidelity CFD; high-resolution filtered sub-models; process design and optimization tools; advanced process control and dynamics; process models; basic data sub-models; and cross-cutting integration tools.

  16. Accelerator Developments and their Application to Cancer Therapy

    SciTech Connect

    Hirao, Yasuo

    2011-05-06

    Basic phenomena in irradiations of X-ray and particle beams and comparison among various radiations are described. Total doses and fractionations for several sites in case of carbon beam are shown in comparison with X-ray and proton beam. Typical results of carbon beam treatments are shown. Original facility was too large. Then, smaller design of 2{sup nd} stage facility of carbon therapy was carried out as well as the further technical developments.

  17. Compact Dielectric Wall Accelerator Development For Intensity Modulated Proton Therapy And Homeland Security Applications

    SciTech Connect

    Chen, Y -; Caporaso, G J; Guethlein, G; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Cook, E; Falabella, S; Gower, E; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Stanley, J; Sullivan, J; Wang, L; Watson, J; Weir, J

    2009-06-17

    Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. Its high electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The DWA concept can be applied to accelerate charge particle beams with any charge to mass ratio and energy. Based on the DWA system, a novel compact proton therapy accelerator is being developed. This proton therapy system will produce individual pulses that can be varied in intensity, energy and spot width. The system will be capable of being sited in a conventional linac vault and provide intensity modulated rotational therapy. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, SiC photoconductive switches and compact proton sources. Applications of the DWA accelerator to problems in homeland security will also be discussed.

  18. New Features of Time Domain Electric-Field Structures in the Auroral Acceleration Region

    SciTech Connect

    Mozer, F.S.; Ergun, R.; Temerin, M.; Cattell, C.; Dombeck, J.; Wygant, J.

    1997-08-01

    The Polar Satellite carries the first three-axis electric field detector flown in the magnetosphere. Its direct measurement of electric field components perpendicular and parallel to the local magnetic field has revealed new classes and features of electric field structures associated with the plasma acceleration that produces discrete auroras and that populates the magnetosphere with plasma of ionospheric origin. These structures, associated with the hydrogen ion cyclotron mode, include very large solitary waves, spiky field structures, wave envelopes of parallel electric fields, and very large amplitude, nonlinear, coherent ion cyclotron waves. {copyright} {ital 1997} {ital The American Physical Society}

  19. Magnetosheath Filamentary Structures Formed by Ion Acceleration at the Quasi-Parallel Bow Shock

    NASA Technical Reports Server (NTRS)

    Omidi, N.; Sibeck, D.; Gutynska, O.; Trattner, K. J.

    2014-01-01

    Results from 2.5-D electromagnetic hybrid simulations show the formation of field-aligned, filamentary plasma structures in the magnetosheath. They begin at the quasi-parallel bow shock and extend far into the magnetosheath. These structures exhibit anticorrelated, spatial oscillations in plasma density and ion temperature. Closer to the bow shock, magnetic field variations associated with density and temperature oscillations may also be present. Magnetosheath filamentary structures (MFS) form primarily in the quasi-parallel sheath; however, they may extend to the quasi-perpendicular magnetosheath. They occur over a wide range of solar wind Alfvénic Mach numbers and interplanetary magnetic field directions. At lower Mach numbers with lower levels of magnetosheath turbulence, MFS remain highly coherent over large distances. At higher Mach numbers, magnetosheath turbulence decreases the level of coherence. Magnetosheath filamentary structures result from localized ion acceleration at the quasi-parallel bow shock and the injection of energetic ions into the magnetosheath. The localized nature of ion acceleration is tied to the generation of fast magnetosonic waves at and upstream of the quasi-parallel shock. The increased pressure in flux tubes containing the shock accelerated ions results in the depletion of the thermal plasma in these flux tubes and the enhancement of density in flux tubes void of energetic ions. This results in the observed anticorrelation between ion temperature and plasma density.

  20. Magnetosheath filamentary structures formed by ion acceleration at the quasi-parallel bow shock

    NASA Astrophysics Data System (ADS)

    Omidi, N.; Sibeck, D.; Gutynska, O.; Trattner, K. J.

    2014-04-01

    Results from 2.5-D electromagnetic hybrid simulations show the formation of field-aligned, filamentary plasma structures in the magnetosheath. They begin at the quasi-parallel bow shock and extend far into the magnetosheath. These structures exhibit anticorrelated, spatial oscillations in plasma density and ion temperature. Closer to the bow shock, magnetic field variations associated with density and temperature oscillations may also be present. Magnetosheath filamentary structures (MFS) form primarily in the quasi-parallel sheath; however, they may extend to the quasi-perpendicular magnetosheath. They occur over a wide range of solar wind Alfvénic Mach numbers and interplanetary magnetic field directions. At lower Mach numbers with lower levels of magnetosheath turbulence, MFS remain highly coherent over large distances. At higher Mach numbers, magnetosheath turbulence decreases the level of coherence. Magnetosheath filamentary structures result from localized ion acceleration at the quasi-parallel bow shock and the injection of energetic ions into the magnetosheath. The localized nature of ion acceleration is tied to the generation of fast magnetosonic waves at and upstream of the quasi-parallel shock. The increased pressure in flux tubes containing the shock accelerated ions results in the depletion of the thermal plasma in these flux tubes and the enhancement of density in flux tubes void of energetic ions. This results in the observed anticorrelation between ion temperature and plasma density.

  1. 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.

  2. Pre-Implementation and Performance Plan for the Latino Development and Technology Accelerator Center

    SciTech Connect

    Quiroga, Marcelo

    2007-03-30

    This report discusses the Latino Development and Technology Accelerator Center (Center) and its innovative economic development program. The chapters describe the organization and the operations of a two-pillar model for training and business acceleration and how the program focuses on the economic development of a disadvantaged Chicago, Illinois, Hispanic community located in Humboldt Park. The Humboldt Park community is located 3 miles west of Chicago's affluent downtown. Humboldt Park residents have income levels below the poverty line and unemployment rates twice the national average.

  3. Superconducting accelerating structure for particle velocities from 0. 12 to 0. 23 c

    SciTech Connect

    Shepard, K.W.; Zinkann, G.P.

    1983-01-01

    A split-ring resonator has been designed for an optimum particle velocity ..beta.. = v/c = 0.16 and a frequency of 145.5 MHz. The ratio of peak-surface electric field to effective accelerating field in the resonator has been reduced 20% from the value obtained in previously developed split-ring resonators. The improved design results from the use of elliptically-sectioned loading arms and drift tubes, which have been enlarged to reduce peak-surface fields and also shaped to eliminate beam-steering effects in the resonator. All fabrication problems presented by the more-complex geometry have been solved, and a prototype superconducting niobium resonator has been completed. An accelerating field of 3.3 MV/m at 4 watts rf input has been so far achieved, corresponding to an effective accelerating potential of 1.17 MV per resonator.

  4. Determination of the acceleration region size in a loop-structured solar flare

    NASA Astrophysics Data System (ADS)

    Guo, J.; Emslie, A. G.; Kontar, E. P.; Benvenuto, F.; Massone, A. M.; Piana, M.

    2012-07-01

    Aims: To study the acceleration and propagation of bremsstrahlung-producing electrons in solar flares, we analyze the evolution of the flare loop size with respect to energy at a variety of times. A GOES M3.7 loop-structured flare starting around 23:55 on 2002 April 14 is studied in detail using Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations. Methods: We construct photon and mean-electron-flux maps in 2-keV energy bins by processing observationally-deduced photon and electron visibilities, respectively, through several image-processing methods: a visibility-based forward-fit (FWD) algorithm, a maximum entropy (MEM) procedure and the uv-smooth (UVS) approach. We estimate the sizes of elongated flares (i.e., the length and width of flaring loops) by calculating the second normalized moments of the intensity in any given map. Employing a collisional model with an extended acceleration region, we fit the loop lengths as a function of energy in both the photon and electron domains. Results: The resulting fitting parameters allow us to estimate the extent of the acceleration region which is between ~ 13 arcsec and ~19 arcsec. Both forward-fit and uv-smooth algorithms provide substantially similar results with a systematically better fit in the electron domain. Conclusions: The consistency of the estimates from these methods provides strong support that the model can reliably determine geometric parameters of the acceleration region. The acceleration region is estimated to be a substantial fraction (~1/2) of the loop extent, indicating that this dense flaring loop incorporates both acceleration and transport of electrons, with concurrent thick-target bremsstrahlung emission.

  5. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

    NASA Astrophysics Data System (ADS)

    Krause, David L.; Kantzos, Pete T.

    2006-01-01

    For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.

  6. Magnetic and Structural Design of a 15 T $Nb_3Sn$ Accelerator Depole Model

    SciTech Connect

    Kashikhin, V. V.; Andreev, N.; Barzi, E.; Novitski, I.; Zlobin, A. V.

    2015-01-01

    Hadron Colliders (HC) are the most powerful discovery tools in modern high energy physics. A 100 TeV scale HC with a nominal operation field of at least 15 T is being considered for the post-LHC era. The choice of a 15 T nominal field requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are the key conditions for realization of such a machine. FNAL has started the development of a 15 T $Nb_{3}Sn$ dipole demonstrator for a 100 TeV scale HC. The magnet design is based on 4-layer shell type coils, graded between the inner and outer layers to maximize the performance. The experience gained during the 11-T dipole R&D campaign is applied to different aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T $Nb_3Sn$ dipole and the steps towards the demonstration model.

  7. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Kantzos, Pete T.

    2006-01-01

    For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110 W Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.

  8. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

    SciTech Connect

    Krause, David L.; Kantzos, Pete T.

    2006-01-20

    For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.

  9. Accelerated hepatocellular carcinoma development in CUL4B transgenic mice.

    PubMed

    Yuan, Jupeng; Jiang, Baichun; Zhang, Aizhen; Qian, Yanyan; Tan, Haining; Gao, Jiangang; Shao, Changshun; Gong, Yaoqin

    2015-06-20

    Cullin 4B (CUL4B) is a component of the Cullin 4B-Ring E3 ligase (CRL4B) complex that functions in proteolysis and in epigenetic regulation. CUL4B possesses tumor-promoting properties and is markedly upregulated in many types of human cancers. To determine the role of CUL4B in liver tumorigenesis, we generated transgenic mice that expressed human CUL4B in livers and other tissues and evaluated the development of spontaneous and chemically-induced hepatocellular carcinomas. We observed that CUL4B transgenic mice spontaneously developed liver tumors at a high incidence at old ages and exhibited enhanced DEN-induced hepatocarcinogenesis. There was a high proliferation rate in the livers of CUL4B transgenic mice that was accompanied by increased levels of Cdk1, Cdk4 and cyclin D1 and decreased level of p16. The transgenic mice also exhibited increased compensatory proliferation after DEN-induced liver injury, which was accompanied by activation of Akt, Erk, p38 and NF-κB. We also found that Prdx3 was downregulated and that DEN induced a higher level of reactive oxygen species in the livers of transgenic mice. Together, our results demonstrate a critical role of CUL4B in hepatocarcinogenesis in mice.

  10. An L-Band Superconducting Traveling Wave Accelerating Structure With Feedback

    SciTech Connect

    Kanareykin, A.; Avrakhov, P.; Yakovlev, V. P.; Solyak, N.; Kazakov, S.

    2009-01-22

    The most severe problem of the International Linear Collider is its high cost, resulting in part from the enormous length of the collider. This length is determined mainly by the achievable accelerating gradient in the RF system of the ILC. In the ILC project the required accelerating gradient is higher than 30 MeV/m. Further improvement of the coupling to the beam may be achieved by using a Traveling Wave SC structure [1]. We have demonstrated that an additional gradient increase of up to 46% may be possible if a {pi}/2 TW SC structure is employed. However, a TW SC structure requires a SC feedback waveguide to return the few GW of circulating RF power from the structure output back to the structure input. The test cavity with feedback is designed to demonstrate the possibility of achieving a significantly higher gradient than existing SC structures. The double-coupler powering excitation and tuning have been studied numerically and the corresponding model results are presented. The proposed double-coupler powering scheme significantly reduces the tuning requirements as long as any of the partial modes of given magnitude and phase are excited independently, providing a clear traveling wave regime of structure operation.

  11. Noninvasive Laser Probing of Ultrashort Single Electron Bunches for Accelerator And Light Source Development

    SciTech Connect

    Bolton, P.R.; /SLAC

    2007-06-11

    Companion development of ultrafast electron beam diagnostics capable of noninvasively resolving single bunch detail is essential for the development of high energy, high brightness accelerator facilities and associated beam-based light source applications. Existing conventional accelerators can exhibit timing-jitter down to the 100 femtosecond level which exceeds their single bunch duration capability. At the other extreme, in relatively jitterless environments, laser-plasma wakefield accelerators (LWFA) can generate single electron bunches of duration estimated to be of order 10 femtoseconds making this setting a valuable testbed for development of broadband electron bunch diagnostics. Characteristics of electro-optic schemes and laser-induced reflectance are discussed with emphasis on temporal resolution.

  12. Refining each process step to accelerate the development of biorefineries

    DOE PAGES

    Chandra, Richard P.; Ragauskas, Art J.

    2016-06-21

    Research over the past decade has been mainly focused on overcoming hurdles in the pretreatment, enzymatic hydrolysis, and fermentation steps of biochemical processing. Pretreatments have improved significantly in their ability to fractionate and recover the cellulose, hemicellulose, and lignin components of biomass while producing substrates containing carbohydrates that can be easily broken down by hydrolytic enzymes. There is a rapid movement towards pretreatment processes that incorporate mechanical treatments that make use of existing infrastructure in the pulp and paper industry, which has experienced a downturn in its traditional markets. Enzyme performance has also made great strides with breakthrough developments inmore » nonhydrolytic protein components, such as lytic polysaccharide monooxygenases, as well as the improvement of enzyme cocktails.The fermentability of pretreated and hydrolyzed sugar streams has been improved through strategies such as the use of reducing agents for detoxification, strain selection, and strain improvements. Although significant progress has been made, tremendous challenges still remain to advance each step of biochemical conversion, especially when processing woody biomass. In addition to technical and scale-up issues within each step of the bioconversion process, biomass feedstock supply and logistics challenges still remain at the forefront of biorefinery research.« less

  13. Accelerating development of a predictive science of climate.

    SciTech Connect

    Drake, John B; Jones, Phil

    2007-01-01

    Climate change and studies of its implications are front page news. Could the heat waves of July 2006 in Europe and the US be caused by global warming? Are increased incidences of strong tropical storms and hurricanes like Katrina to be expected? Will coastal cities be flooded due to sea level rise? The National Climatic Data Center (NCDC) which archives all weather data for the nation reports that global surface temperatures have increased at a rate near 0.6 C over the last century but that the trend is three times larger since 1976 [Easterling, 2006]. Will this rate continue or will climate change be even more abrupt? Stepping back from the flurry of questions, scientists must take a systematic approach and develop a predictive framework. With responsibility for advising on energy and technology strategies, the Department of Energy Office of Biological and Environmental Research has chosen to bolster the science of climate in order to get the story straight on the factors that cause climate change and the role of carbon loading from fossil fuel use.

  14. Refining each process step to accelerate the development of biorefineries

    SciTech Connect

    Chandra, Richard P.; Ragauskas, Art J.

    2016-06-21

    Research over the past decade has been mainly focused on overcoming hurdles in the pretreatment, enzymatic hydrolysis, and fermentation steps of biochemical processing. Pretreatments have improved significantly in their ability to fractionate and recover the cellulose, hemicellulose, and lignin components of biomass while producing substrates containing carbohydrates that can be easily broken down by hydrolytic enzymes. There is a rapid movement towards pretreatment processes that incorporate mechanical treatments that make use of existing infrastructure in the pulp and paper industry, which has experienced a downturn in its traditional markets. Enzyme performance has also made great strides with breakthrough developments in nonhydrolytic protein components, such as lytic polysaccharide monooxygenases, as well as the improvement of enzyme cocktails.The fermentability of pretreated and hydrolyzed sugar streams has been improved through strategies such as the use of reducing agents for detoxification, strain selection, and strain improvements. Although significant progress has been made, tremendous challenges still remain to advance each step of biochemical conversion, especially when processing woody biomass. In addition to technical and scale-up issues within each step of the bioconversion process, biomass feedstock supply and logistics challenges still remain at the forefront of biorefinery research.

  15. Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity

    PubMed Central

    Clayton, C. E.; Adli, E.; Allen, J.; An, W.; Clarke, C. I.; Corde, S.; Frederico, J.; Gessner, S.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Litos, M.; Lu, W.; Marsh, K. A.; Mori, W. B.; Vafaei-Najafabadi, N.; Xu, X.; Yakimenko, V.

    2016-01-01

    The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.). Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m−1 to a similar degree of accuracy. These results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity. PMID:27527569

  16. Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity

    SciTech Connect

    Clayton, C. E.; Adli, E.; Allen, J.; An, W.; Clarke, C. I.; Corde, S.; Frederico, J.; Gessner, S.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Litos, M.; Lu, W.; Marsh, K. A.; Mori, W. B.; Vafaei-Najafabadi, N.; Xu, X.; Yakimenko, V.

    2016-08-16

    The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.). Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m–1 to a similar degree of accuracy. Lastly, these results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity.

  17. Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity

    DOE PAGES

    Clayton, C. E.; Adli, E.; Allen, J.; ...

    2016-08-16

    The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.).more » Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m–1 to a similar degree of accuracy. Lastly, these results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity.« less

  18. Ion Acceleration at Earth, Saturn and Jupiter and its Global Impact on Magnetospheric Structure

    NASA Astrophysics Data System (ADS)

    Brandt, Pontus

    2016-07-01

    The ion plasma pressures at Earth, Saturn and Jupiter are significant players in the electrodynamic force-balance that governs the structure and dynamics of these magnetospheres. There are many similarities between the physical mechanisms that are thought to heat the ion plasma to temperatures that even exceed those of the solar corona. In this presentation we compare the ion acceleration mechanisms at the three planetary magnetospheres and discuss their global impacts on magnetopsheric structure. At Earth, bursty-bulk flows, or "bubbles", have been shown to accelerate protons and O+ to high energies by the earthward moving magnetic dipolarization fronts. O+ ions display a more non-adiabatic energization in response to these fronts than protons do as they are energized and transported in to the ring-current region where they reach energies of several 100's keV. We present both in-situ measurements from the NASA Van Allen Probes Mission and global Energetic Neutral (ENA) images from the High-Energy Neutral Atom (HENA) Camera on board the IMAGE Mission, that illustrate these processes. The global impact on the magnetospheric structure is explored by comparing the empirical magnetic field model TS07d for given driving conditions with global plasma pressure distributions derived from the HENA images. At Saturn, quasi-periodic energization events, or large-scale injections, occur beyond about 9 RS around the post-midnight sector, clearly shown by the Ion and Neutral Atom Camera (INCA) on board the Cassini mission. In contrast to Earth, the corotational drift dominates even the energetic ion distributions. The large-scale injections display similar dipolarization front features can be found and there are indications that like at Earth the O+ responds more non-adiabatically than protons do. However, at Saturn there are also differences in that there appears to be energization events deep in the inner magnetosphere (6-9 RS) preferentially occurring in the pre

  19. Residual acceleration data on IML-1: Development of a data reduction and dissemination plan

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. Iwan D.; Wolf, Randy

    1992-01-01

    The main thrust of our work in the third year of contract NAG8-759 was the development and analysis of various data processing techniques that may be applicable to residual acceleration data. Our goal is the development of a data processing guide that low gravity principal investigators can use to assess their need for accelerometer data and then formulate an acceleration data analysis strategy. The work focused on the flight of the first International Microgravity Laboratory (IML-1) mission. We are also developing a data base management system to handle large quantities of residual acceleration data. This type of system should be an integral tool in the detailed analysis of accelerometer data. The system will manage a large graphics data base in the support of supervised and unsupervised pattern recognition. The goal of the pattern recognition phase is to identify specific classes of accelerations so that these classes can be easily recognized in any data base. The data base management system is being tested on the Spacelab 3 (SL3) residual acceleration data.

  20. Complete multipactor suppression in an X-band dielectric-loaded accelerating structure

    SciTech Connect

    Jing, C.; Gold, S. H.; Fischer, Richard; Gai, W.

    2016-05-09

    Multipactor is a major issue limiting the gradient of rf-driven Dielectric-Loaded Accelerating (DLA) structures. Theoretical models have predicted that an axial magnetic field applied to DLA structures may completely block the multipactor discharge. However, previous attempts to demonstrate this magnetic field effect in an X-band traveling-wave DLA structure were inconclusive, due to the axial variation of the applied magnetic field, and showed only partial suppression of the multipactor loading [Jing et al., Appl. Phys. Lett. 103, 213503 (2013)]. The present experiment has been performed under improved conditions with a uniform axial magnetic field extending along the length of an X-band standing-wave DLA structure. Multipactor loading began to be continuously reduced starting from 3.5 kG applied magnetic field and was completely suppressed at 8 kG. Dependence of multipactor suppression on the rf gradient inside the DLA structure was also measured.

  1. Acceleration ground test program to verify GAS payload No. 559 structure/support avionics and experiment structural integrity

    NASA Technical Reports Server (NTRS)

    Cassanto, John M.; Cassanto, Valerie A.

    1988-01-01

    Acceleration ground tests were conducted on the Get Away Special (GAS) payload 559 to verify the structural integrity of the structure/support avionics and two of the planned three flight experiments. The ITA (Integrated Test Area) Standardized Experiment Module (ISEM) structure was modified to accommodate the experiments for payload 559. The ISEM avionics consisted of a heavy duty sliver zinc power supply, three orthogonal-mounted low range microgravity accelerometers, a tri-axis high range accelerometer, a solid state recorder/programmer sequencer, and pressure and temperature sensors. The tests were conducted using the Gravitational Plant Physiology Laboratory Centrifuge of the University City Science Center in Philadelphia, PA. The launch-powered flight steady state acceleration profile of the shuttle was simulated from lift-off through jettison of the External Tank (3.0 g's). Additional tests were conducted at twice the nominal powered flight acceleration levels (6 g's) and an over-test condition of four times the powered flight loads to 12.6 g's. The present test program has demonstrated the value of conducting ground tests to verify GAS payload experiment integrity and operation before flying on the shuttle.

  2. The MIT Accelerator Laboratory for Diagnostic Development for OMEGA, Z and the NIF

    NASA Astrophysics Data System (ADS)

    Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Orozco, D.; Rinderknecht, H. G.; Rojas Herrera, J.; Rosenberg, M.; Sio, H.; Zylstra, A.; Frenje, J.; Li, C. K.; Seguin, F. H.; Hahn, K.; Jones, B.; Ruiz, C. L.; Sangster, T. C.

    2014-10-01

    The MIT Linear Electrostatic Ion Accelerator generates D-D and D-3He fusion products, which are used for development of nuclear diagnostics for OMEGA, Z, and the NIF. Fusion reaction rates around 106 s-1 are routinely achieved with this accelerator, and fluence and energy of the fusion products are accurately characterized. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) CVD-diamond-based bang time detector. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  3. The MIT HEDP Accelerator Facility for Diagnostic Development for OMEGA, Z, and the NIF

    NASA Astrophysics Data System (ADS)

    Parker, C. E.; Gatu Johnson, M.; Birkel, A.; Kabadi, N. V.; Lahmann, B.; Milanese, L. M.; Simpson, R. A.; Sio, H.; Sutcliffe, G. D.; Wink, C.; Frenje, J. A.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Leeper, R.; Ruiz, C. L.; Sangster, T. C.

    2016-10-01

    The MIT HEDP Accelerator Facility utilizes a 135-keV linear electrostatic ion accelerator, DT and DD neutron sources, and two x-ray sources for development and characterization of nuclear diagnostics for OMEGA, Z, and the NIF. The accelerator generates DD and D3He fusion products through the acceleration of D+ ions onto a 3He-doped Erbium-Deuteride target. Accurately characterized fusion product rates of around 106 s-1 are routinely achieved. The DT and DD neutron sources generate up to 6x108, and 1x107 neutrons/s, respectively. One x-ray generator is a thick-target W source with a peak energy of 225 keV and a maximum dose rate of 12 Gy/min; the other uses Cu, Mo, or Ti elemental tubes to generate x-rays with a maximum energy of 40 keV. Diagnostics developed and calibrated at this facility include CR-39-based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) and Magnetic PTOF CVD-diamond-based bang time detectors. The accelerator is also a valuable hands-on tool for graduate and undergraduate education at MIT. This work was supported in part by the U.S. DoE, SNL, LLE and LLNL.

  4. Structural Basis for Accelerated Cleavage of Bovine Pancreatic Trypsin Inhibitor (BPTI) by Human Mesotrypsin

    SciTech Connect

    Salameh,M.; Soares, A.; Hockla, A.; Radisky, E.

    2008-01-01

    Human mesotrypsin is an isoform of trypsin that displays unusual resistance to polypeptide trypsin inhibitors and has been observed to cleave several such inhibitors as substrates. Whereas substitution of arginine for the highly conserved glycine 193 in the trypsin active site has been implicated as a critical factor in the inhibitor resistance of mesotrypsin, how this substitution leads to accelerated inhibitor cleavage is not clear. Bovine pancreatic trypsin inhibitor (BPTI) forms an extremely stable and cleavage-resistant complex with trypsin, and thus provides a rigorous challenge of mesotrypsin catalytic activity toward polypeptide inhibitors. Here, we report kinetic constants for mesotrypsin and the highly homologous (but inhibitor sensitive) human cationic trypsin, describing inhibition by, and cleavage of BPTI, as well as crystal structures of the mesotrypsin-BPTI and human cationic trypsin-BPTI complexes. We find that mesotrypsin cleaves BPTI with a rate constant accelerated 350-fold over that of human cationic trypsin and 150,000-fold over that of bovine trypsin. From the crystal structures, we see that small conformational adjustments limited to several side chains enable mesotrypsin-BPTI complex formation, surmounting the predicted steric clash introduced by Arg-193. Our results show that the mesotrypsin-BPTI interface favors catalysis through (a) electrostatic repulsion between the closely spaced mesotrypsin Arg-193 and BPTI Arg-17, and (b) elimination of two hydrogen bonds between the enzyme and the amine leaving group portion of BPTI. Our model predicts that these deleterious interactions accelerate leaving group dissociation and deacylation.

  5. Conceptual Design of Dielectric Accelerating Structures for Intense Neutron and Monochromatic X-ray Sources

    SciTech Connect

    Blanovsky, Anatoly

    2004-12-07

    Bright compact photon sources, which utilize electron beam interaction with periodic structures, may benefit a broad range of medical, industrial and scientific applications. A class of dielectric-loaded periodic structures for hard and soft X-ray production has been proposed that would provide a high accelerating gradient when excited by an external RF and/or primary electron beam. Target-distributed accelerators (TDA), in which an additional electric field compensates for lost beam energy in internal targets, have been shown to provide the necessary means to drive a high flux subcritical reactor (HFSR) for nuclear waste transmutation. The TDA may also be suitable for positron and nuclear isomer production, X-ray lithography and monochromatic computer tomography. One of the early assumptions of the theory of dielectric wake-field acceleration was that, in electrodynamics, the vector potential was proportional to the scalar potential. The analysis takes into consideration a wide range of TDA design aspects including the wave model of observed phenomena, a layered compound separated by a Van der Waals gap and a compact energy source based on fission electric cells (FEC) with a multistage collector. The FEC is a high-voltage power source that directly converts the kinetic energy of the fission fragments into electrical potential of about 2MV.

  6. Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

    PubMed Central

    He, Z.-H.; Beaurepaire, B.; Nees, J. A.; Gallé, G.; Scott, S. A.; Pérez, J. R. Sánchez; Lagally, M. G.; Krushelnick, K.; Thomas, A. G. R.; Faure, J.

    2016-01-01

    Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wakefield-accelerated electron bunches for time-resolved electron diffraction measurements of the structural dynamics of single-crystal silicon nano-membranes pumped by an ultrafast laser pulse. In our proof-of-concept study, we resolve the silicon lattice dynamics on a picosecond time scale by deflecting the momentum-time correlated electrons in the diffraction peaks with a static magnetic field to obtain the time-dependent diffraction efficiency. Further improvements may lead to femtosecond temporal resolution, with negligible pump-probe jitter being possible with future laser-wakefield-accelerator ultrafast-electron-diffraction schemes. PMID:27824086

  7. Developing a Model of Compulsory Basic Education Completion Acceleration in Support of Millennium Development Goals in Magelang, Indonesia

    ERIC Educational Resources Information Center

    Sukarno; Haryati, Sri

    2015-01-01

    This article reports Year One of a two-year study to develop a model to accelerate compulsory basic education completion toward Millennium Development Goals (MDGs) in Magelang, Indonesia. The study focuses on five issues: (1) profile of MDGs in Magelang, (2) achievement of MDGs, (3) problems in MDGs implementation, (4) model of compulsary basic…

  8. X-band accelerator structures: On going R&D at the INFN

    NASA Astrophysics Data System (ADS)

    Gatti, G.; Marcelli, A.; Spataro, B.; Dolgashev, V.; Lewandowski, J.; Tantawi, S. G.; Yeremian, A. D.; Higashi, Y.; Rosenzweig, J.; Sarti, S.; Caliendo, C.; Castorina, G.; Cibin, G.; Carfora, L.; Leonardi, O.; Rigato, V.; Campostrini, M.

    2016-09-01

    The next generation of accelerators, from the compact to the large infrastructure dedicated to high energy physics, is highly demanding in terms of accelerating gradients. To upgrade performances of X band linacs at 11.424 GHz many resources are devoted to achieve high accelerating gradients and at the same time to obtain a high reliability. In the framework of a three-year funded project by the Vth Committee of the INFN to the Laboratori Nazionali di Frascati (LNF) and to the Laboratori Nazionali di Legnaro (LNL). Within a broad international collaboration the LNF has been involved in the design, manufacture and test of compact high power standing wave (SW) sections operating at high frequency while LNL is actively involved in the development of new materials and multilayers using PVD (Physical Vapor Deposition) methods. We will report about the status of the accelerating device and of the different ongoing R&D activities and characterization procedures such as tests of different materials and metallic coatings.

  9. Measurements of ultimate accelerating gradients in the SLAC disk-loaded structure

    SciTech Connect

    Wang, J.W.; Loew, G.A.

    1985-03-01

    This paper is a status report on an on-going program at SLAC to study accelerator structures under high-gradient electric field conditions. The study is a part of a much broader program dealing with future linear colliders. The accelerating gradient that might be achievable in such machines is a crucial parameter because once the beam energy is selected, the gradient determines the length of the linac and directly or indirectly affects the choice of many other parameters. To reach 100 MV/m in a conventional 3 m constant-gradient section without SLED, one would need a klystron with a peak power output of 900 MW. Since such a tube is not available, we decided to use a short standing-wave section in which the resonant fields can build up. The design criteria for this section, the fabrication, matching and tuning, the experimental set-up and the results are described. 6 refs., 5 figs., 1 tab.

  10. Spectroscopic characterization of the oligomeric surface structures on polyamide materials formed during accelerated aging.

    PubMed

    Chernev, Boril S; Eder, Gabriele C

    2011-10-01

    Crystalline surface species were observed at the surface of polyamide 12 materials upon accelerated aging. After detection of the depositions with scanning electron microscopy (SEM), the crystalline surface precipitations were analyzed with Fourier transform infrared (FT-IR) and Raman imaging microscopy. These surface species were supposed to be cyclic oligomers (dimer and trimer) of the PA12 monomer laurolactam, which are usually present in polyamide materials and tend to migrate to the surface when the material is subjected to accelerated aging. The evidence for the chemical identity of the crystalline surface structures to be mainly the cyclic dimer and trimer of laurolactam was given by melting-point identification and mass spectroscopic analysis of the methanol eluate of the surface. The Raman and FT-IR spectra of the mixture were extracted from the recorded images.

  11. HOM-Free Linear Accelerating Structure for e+ e- Linear Collider at C-Band

    SciTech Connect

    Kubo, Kiyoshi

    2003-07-07

    HOM-free linear acceleration structure using the choke mode cavity (damped cavity) is now under design for e{sup +}e{sup -} linear collider project at C-band frequency (5712 MHz). Since this structure shows powerful damping effect on most of all HOMs, there is no multibunch problem due to long range wakefields. The structure will be equipped with the microwave absorbers in each cells and also the in-line dummy load in the last few cells. The straightness tolerance for 1.8 m long structure is closer than 30 {micro}m for 25% emittance dilution limit, which can be achieved by standard machining and braising techniques. Since it has good vacuum pumping conductance through annular gaps in each cell, instabilities due to the interaction of beam with the residual-gas and ions can be minimized.

  12. Accelerated Learning in Adult Education and Training and Development. Trends and Issues Alert.

    ERIC Educational Resources Information Center

    Imel, Susan

    In adult education, the term "accelerated learning" (AL) is usually associated with programs designed to meet the needs of adult learners whose many commitments prevent them from participating in traditional programs. Within the field of training and development, however, AL identifies an approach to learning that is multidimensional in…

  13. Accelerated Professional Development and Peer Consultation: Two Strategies for Continuing Professional Education for Nurses.

    ERIC Educational Resources Information Center

    Hart, Gail; Clinton, Michael; Edwards, Helen; Evans, Katie; Lunney, Paul; Posner, Natasha; Tooth, Barbara; Weir, Derek; Ryan, Yoni

    2000-01-01

    A comparison was made of accelerated professional development (APD) for nurses (n=64), involving peer consultation and reflective practice, and peer consultation alone (n=30). Although APD participants had a higher completion rate, improvements in caregiver behaviors and work environment were not significantly different. (SK)

  14. Methoprene and protein supplements accelerate reproductive development and improve mating success of male tephritid flies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have been studying the physiological mechanisms responsible for coordination of reproductive maturity and sex pheromone communication in males of tephritid flies in order to develop methods for acceleration of reproductive maturity among sterilized males. Our studies revealed that the juvenile ho...

  15. Accelerating the Early Numeracy Development of Kindergartners with Limited Working Memory Skills through Remedial Education

    ERIC Educational Resources Information Center

    Toll, Sylke W. M.; Van Luit, Johannes E. H.

    2013-01-01

    Background: Young children with limited working memory skills are a special interest group among all children that score below average on early numeracy tests. This study examines the effect of accelerating the early numeracy development of these children through remedial education, by comparing them with children with typically working memory…

  16. Experimental high gradient testing of a 17.1 GHz photonic band-gap accelerator structure

    NASA Astrophysics Data System (ADS)

    Munroe, Brian J.; Zhang, JieXi; Xu, Haoran; Shapiro, Michael A.; Temkin, Richard J.

    2016-03-01

    We report the design, fabrication, and high gradient testing of a 17.1 GHz photonic band-gap (PBG) accelerator structure. Photonic band-gap (PBG) structures are promising candidates for electron accelerators capable of high-gradient operation because they have the inherent damping of high order modes required to avoid beam breakup instabilities. The 17.1 GHz PBG structure tested was a single cell structure composed of a triangular array of round copper rods of radius 1.45 mm spaced by 8.05 mm. The test assembly consisted of the test PBG cell located between conventional (pillbox) input and output cells, with input power of up to 4 MW from a klystron supplied via a TM01 mode launcher. Breakdown at high gradient was observed by diagnostics including reflected power, downstream and upstream current monitors and visible light emission. The testing procedure was first benchmarked with a conventional disc-loaded waveguide structure, which reached a gradient of 87 MV /m at a breakdown probability of 1.19 ×10-1 per pulse per meter. The PBG structure was tested with 100 ns pulses at gradient levels of less than 90 MV /m in order to limit the surface temperature rise to 120 K. The PBG structure reached up to 89 MV /m at a breakdown probability of 1.09 ×10-1 per pulse per meter. These test results show that a PBG structure can simultaneously operate at high gradients and low breakdown probability, while also providing wakefield damping.

  17. Structural Analysis of Communication Development.

    ERIC Educational Resources Information Center

    Conville, Richard L.

    This paper discusses the question of the legitimacy of applying structural analysis to actual human behavior and illustrates its legitimacy by using the reasoning in an essay by Paul Ricoeur. It then asks if the principles of communication development (obliqueness, exchange, and dying) derived from Helen Keller's experience of communication…

  18. Rapid analysis of scattering from periodic dielectric structures using accelerated Cartesian expansions

    DOE PAGES

    Baczewski, Andrew David; Miller, Nicholas C.; Shanker, Balasubramaniam

    2012-03-22

    Here, the analysis of fields in periodic dielectric structures arise in numerous applications of recent interest, ranging from photonic bandgap structures and plasmonically active nanostructures to metamaterials. To achieve an accurate representation of the fields in these structures using numerical methods, dense spatial discretization is required. This, in turn, affects the cost of analysis, particularly for integral-equation-based methods, for which traditional iterative methods require Ο(Ν2) operations, Ν being the number of spatial degrees of freedom. In this paper, we introduce a method for the rapid solution of volumetric electric field integral equations used in the analysis of doubly periodic dielectricmore » structures. The crux of our method is the accelerated Cartesian expansion algorithm, which is used to evaluate the requisite potentials in Ο(Ν) cost. Results are provided that corroborate our claims of acceleration without compromising accuracy, as well as the application of our method to a number of compelling photonics applications.« less

  19. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head.

    PubMed

    Kamino, Yuichiro; Miura, Sadao; Kokubo, Masaki; Yamashita, Ichiro; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-05-01

    We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm X 0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)-Ib (mA) X 0.00808 (MeV/mA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGy/min at the rated x-ray output of 500 cGy/min from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1.

  20. Helicon Plasma Injector and Ion Cyclotron Acceleration Development in the VASIMR Experiment

    NASA Technical Reports Server (NTRS)

    Squire, Jared P.; Chang, Franklin R.; Jacobson, Verlin T.; McCaskill, Greg E.; Bengtson, Roger D.; Goulding, Richard H.

    2000-01-01

    In the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) radio frequency (rf) waves both produce the plasma and then accelerate the ions. The plasma production is done by action of helicon waves. These waves are circular polarized waves in the direction of the electron gyromotion. The ion acceleration is performed by ion cyclotron resonant frequency (ICRF) acceleration. The Advanced Space Propulsion Laboratory (ASPL) is actively developing efficient helicon plasma production and ICRF acceleration. The VASIMR experimental device at the ASPL is called VX-10. It is configured to demonstrate the plasma production and acceleration at the 10kW level to support a space flight demonstration design. The VX-10 consists of three electromagnets integrated into a vacuum chamber that produce magnetic fields up to 0.5 Tesla. Magnetic field shaping is achieved by independent magnet current control and placement of the magnets. We have generated both helium and hydrogen high density (>10(exp 18) cu m) discharges with the helicon source. ICRF experiments are underway. This paper describes the VX-10 device, presents recent results and discusses future plans.

  1. Development of a 15 T Nb3Sn accelerator dipole demonstrator at Fermilab

    DOE PAGES

    Novitski, I.; Andreev, N.; Barzi, E.; ...

    2016-06-01

    Here, a 100 TeV scale Hadron Collider (HC) with a nominal operation field of at least 15 T is being considered for the post-LHC era, which requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are the key conditions for realization of such a machine. FNAL has started the development of a 15 T Nb3Sn dipole demonstrator for a 100 TeV scale HC. The magnet design is based on 4-layer shell type coils, graded between the inner and outer layers to maximize the performance and reduce themore » cost. The experience gained during the Nb3Sn magnet R&D is applied to different aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T Nb3Sn dipole and the steps towards the demonstration model fabrication.« less

  2. Mosaic evolution of neural development in anurans: acceleration of spinal cord development in the direct developing frog Eleutherodactylus coqui.

    PubMed

    Schlosser, Gerhard

    2003-02-01

    Previous studies have shown that spinal cord development in direct developing frogs of the genus Eleutherodactylus, which have evolutionarily lost the tadpole stage, differs from that in biphasically developing anurans (with the larval and the adult stage separated by metamorphosis). The present study of spinal cord development in Eleutherodactylus coqui provides additional information about neurogenesis, neuronal differentiation and growth analyzed by immunostaining for proliferating cell nuclear antigen (PCNA), in situ hybridization for NeuroD, and morphometric measurements in various developmental stages. Furthermore, spinal cord development in the frogs Discoglossus pictus, Xenopus laevis, and Physalaemus pustulosus, which belong to different anuran families but all exhibit biphasic development, was similarly analyzed. This comparative analysis allows inference of the ancestral anuran pattern of spinal cord development and how it has been modified during the evolution of Eleutherodactylus. All biphasically developing frogs analyzed share a similar pattern of spinal cord development, suggesting that this is ancestral for anurans: after neural tube closure, levels of proliferation and neurogenesis in the spinal cord were low throughout embryogenesis until they were upregulated drastically at early larval stages followed by development of the lateral motor columns. In contrast, no such quiescent embryonic period exists in E. coqui, where rapid growth, high levels of proliferation and neurogenesis, and early formation of lateral motor columns occur shortly after neural tube closure, while other parts of the central nervous system develop more slowly. Thus, spinal cord development has been accelerated during the evolution of Eleutherodactylus relative to the development of other parts of the central nervous system, probably related to the precocious development of limbs in this lineage.

  3. 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.

  4. 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.

  5. Accelerated stress testing of thin film solar cells: Development of test methods and preliminary results

    NASA Technical Reports Server (NTRS)

    Lathrop, J. W.

    1985-01-01

    If thin film cells are to be considered a viable option for terrestrial power generation their reliability attributes will need to be explored and confidence in their stability obtained through accelerated testing. Development of a thin film accelerated test program will be more difficult than was the case for crystalline cells because of the monolithic construction nature of the cells. Specially constructed test samples will need to be fabricated, requiring committment to the concept of accelerated testing by the manufacturers. A new test schedule appropriate to thin film cells will need to be developed which will be different from that used in connection with crystalline cells. Preliminary work has been started to seek thin film schedule variations to two of the simplest tests: unbiased temperature and unbiased temperature humidity. Still to be examined are tests which involve the passage of current during temperature and/or humidity stress, either by biasing in the forward (or reverse) directions or by the application of light during stress. Investigation of these current (voltage) accelerated tests will involve development of methods of reliably contacting the thin conductive films during stress.

  6. Fine-grained parallelism accelerating for RNA secondary structure prediction with pseudoknots based on FPGA.

    PubMed

    Xia, Fei; Jin, Guoqing

    2014-06-01

    PKNOTS is a most famous benchmark program and has been widely used to predict RNA secondary structure including pseudoknots. It adopts the standard four-dimensional (4D) dynamic programming (DP) method and is the basis of many variants and improved algorithms. Unfortunately, the O(N(6)) computing requirements and complicated data dependency greatly limits the usefulness of PKNOTS package with the explosion in gene database size. In this paper, we present a fine-grained parallel PKNOTS package and prototype system for accelerating RNA folding application based on FPGA chip. We adopted a series of storage optimization strategies to resolve the "Memory Wall" problem. We aggressively exploit parallel computing strategies to improve computational efficiency. We also propose several methods that collectively reduce the storage requirements for FPGA on-chip memory. To the best of our knowledge, our design is the first FPGA implementation for accelerating 4D DP problem for RNA folding application including pseudoknots. The experimental results show a factor of more than 50x average speedup over the PKNOTS-1.08 software running on a PC platform with Intel Core2 Q9400 Quad CPU for input RNA sequences. However, the power consumption of our FPGA accelerator is only about 50% of the general-purpose micro-processors.

  7. Narrow bandwidth Thomson photon source and diagnostic development using laser-plasma accelerators

    NASA Astrophysics Data System (ADS)

    Geddes, Cameron G. R.; Tsai, Hai-En; van Tilborg, Jeroen; Benedetti, Carlo; Esarey, Eric; Friedman, Alex; Grote, David; Ludewigt, Bernhard; Nakamura, Kei; Quiter, Brian J.; Schroeder, Carl B.; Steinke, Sven; Swanson, Kelly; Toth, Csaba; Vay, Jean-Luc; Vetter, Kai; Zhang, Yigong; Leemans, Wim

    2017-03-01

    Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs), and these sources at the same time provide precision diagnostics of beam evolution to support LPA development. We review design of experiments and laser capabilities to realize a photon source, integrating LPA acceleration for compactness, control of scattering to increase photon flux, and electron deceleration to mitigate beam dump size. These experiments are developing a compact photon source system with the potential to enable new monoenergetic photon applications currently restricted by source size, including nuclear nonproliferation. Diagnostic use of the energy-angle spectra of Thomson scattered photons is presented to support development of LPAs to meet the needs of advanced high yield/low-energy-spread photon sources and future high energy physics colliders.

  8. Using combinatorial bioinformatics methods to analyze annual perspective changes of influenza viruses and to accelerate development of effective vaccines.

    PubMed

    Hu, Yu-Jen; Chow, Kuan-Chih; Liu, Ching-Chuan; Lin, Li-Jen; Wang, Sheng-Cheng; Wang, Shulhn-Der

    2015-08-01

    The standard World Health Organization procedure for vaccine development has provided a guideline for influenza viruses, but no systematic operational model. We recently designed a systemic analysis method to evaluate annual perspective sequence changes of influenza virus strains. We applied dnaml of PHYLIP 3.69, developed by Joseph Felsenstein of Washington University, and ClustalX2, developed by Larkin et al, for calculating, comparing, and localizing the most plausible vaccine epitopes. This study identified the changes in biological sequences and associated alignment alterations, which would ultimately affect epitope structures, as well as the plausible hidden features to search for the most conserved and effective epitopes for vaccine development. Addition our newly designed systemic analysis method to supplement the WHO guidelines could accelerate the development of urgently needed vaccines that might concurrently combat several strains of viruses within a shorter period.

  9. Analysis of requirements for accelerating the development of geothermal energy resources in California

    NASA Technical Reports Server (NTRS)

    Fredrickson, C. D.

    1978-01-01

    Various resource data are presented showing that geothermal energy has the potential of satisfying a singificant part of California's increasing energy needs. General factors slowing the development of geothermal energy in California are discussed and required actions to accelerate its progress are presented. Finally, scenarios for developing the most promising prospects in the state directed at timely on-line power are given. Specific actions required to realize each of these individual scenarios are identified.

  10. Accelerating adiabatic quantum transfer for three-level Λ-type structure systems via picture transformation

    NASA Astrophysics Data System (ADS)

    Kang, Yi-Hao; Wu, Qi-Cheng; Chen, Ye-Hong; Shi, Zhi-Cheng; Song, Jie; Xia, Yan

    2017-04-01

    In this paper, we investigate the quantum transfer for the system with three-level Λ-type structure, and construct a shortcut to the adiabatic passage via picture transformation to speed up the evolution. We can design the pulses directly without any additional couplings. Moreover, by choosing suitable control parameters, the Rabi frequencies of pulses can be expressed by the linear superpositions of Gaussian functions, which could be easily realized in experiments. Compared with the previous works using the stimulated Raman adiabatic passage, the quantum transfer can be significantly accelerated with the present scheme.

  11. New electronic control systems for ILU accelerators, initiating the development of unique irradiation systems based on them

    NASA Astrophysics Data System (ADS)

    Bezuglov, V. V.; Bryazgin, A. A.; Vlasov, A. Y.; Kokin, E. N.; Shtarklev, E. A.

    2016-12-01

    This study is devoted to the development and industrial implementation of automated electronbeam irradiation systems based on ILU type accelerators, as well as the development of electronics and software for the creation of new technological solutions on the industrial application of accelerated electron beams. This study gives a description of the power-supply and control systems for an independent electronbeam scanning unit included in a universal one- or four-window extraction unit. The new control and protection systems for ILU accelerator pulsed power supply are also described; these systems resulted in the development of a unique 3-modulator power supply for the multiresonator ILU-14 accelerator.

  12. 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.

  13. Uniform Plasma Etching of Complex Shaped Three Dimensional Niobium Structures for Particle Accelerators

    NASA Astrophysics Data System (ADS)

    Upadhyay, Janardan; Im, Do; Peshl, Jeremy; Popovic, Svetozar; Vuskovic, Lepsha; Phillips, Larry; Valente-Felliciano, Anne-Marie

    2014-10-01

    Complex shaped three dimensional niobium structures are used in particle accelerators as super conducting radio frequency (SRF) cavities. The inner surfaces of these structures have to be chemically etched for better performance, as SRF performance parameters are very sensitive to their properties. Plasma etching of inner surface of three dimensional niobium structures has not been reported even though plasma etching of niobium has been reported earlier for Josephson junction and other applications. We are proposing an RF capacitively coupled coaxial (ccp) plasma etching method for nano machining of niobium structures for SRF applications. We are using gas mixture of Argon and Chlorine. We report the effects of the pressure, RF power, gas concentration, shape and size of the inner electrode, temperature of the structure, DC bias voltage and residence time on the etch rate of the niobium. We also show the method to reduce the asymmetry effect in coaxial ccp by changing the shape of the inner electrode in cylindrical structure, as well as a method to overcome the severe loading effect in etching of 3D structures for uniform mass removal purpose. Supported by DOE under Grant No. DE-SC0007879. J.U. acknowledges support by JSA/DOE via DE-AC05-06OR23177.

  14. A Wind-Tunnel Investigation of the Development of Lift on Wings in Accelerated Longitudinal Motion

    NASA Technical Reports Server (NTRS)

    Turner, Thomas R.

    1960-01-01

    An investigation was made in the Langley 300 MPH 7- by 10-foot tunnel to determine the development of lift on a wing during a simulated constant-acceleration catapult take-off. The investigation included models of a two-dimensional wing, an unswept wing having an aspect ratio of 6, a 35 deg. swept wing having an aspect ratio of 3.05, and a 60 deg. delta wing having an aspect ratio of 2.31. All the wings investigated developed at least 90 percent of their steady-state lift in the first 7 chord lengths of travel. The development of lift was essentially independent of the acceleration when based on chord lengths traveled, and was in qualitative agreement with theory.

  15. Acceleration of solar wind ions to 1 MeV by electromagnetic structures upstream of the Earth's bow shock

    NASA Astrophysics Data System (ADS)

    Stasiewicz, K.; Markidis, S.; Eliasson, B.; Strumik, M.; Yamauchi, M.

    2013-05-01

    We present measurements from the ESA/NASA Cluster mission that show in situ acceleration of ions to energies of 1 MeV outside the bow shock. The observed heating can be associated with the presence of electromagnetic structures with strong spatial gradients of the electric field that lead to ion gyro-phase breaking and to the onset of chaos in ion trajectories. It results in rapid, stochastic acceleration of ions in the direction perpendicular to the ambient magnetic field. The electric potential of the structures can be compared to a field of moguls on a ski slope, capable of accelerating and ejecting the fast running skiers out of piste. This mechanism may represent the universal mechanism for perpendicular acceleration and heating of ions in the magnetosphere, the solar corona and in astrophysical plasmas. This is also a basic mechanism that can limit steepening of nonlinear electromagnetic structures at shocks and foreshocks in collisionless plasmas.

  16. Induction linear accelerators

    NASA Astrophysics Data System (ADS)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typically<10) structures and very large beam pipes. This combination increases the beam breakup limited maximum currents to of order kiloamperes. The micropulse lengths of these machines are measured in 10's of nanoseconds and duty factors as high as 10-4 have been achieved. Until recently the major problem with these machines has been associated with the pulse power drive. Beam currents of kiloamperes and accelerating potentials of megavolts require peak power drives of gigawatts since no energy is stored in the structure. The marriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  17. A fast "kicker" using a two-channel rectangular dielectric wakefield accelerator structure

    NASA Astrophysics Data System (ADS)

    Marshall, Thomas C.; Shchelkunov, Sergey V.; Sotnikov, Gennadij V.; Hirshfield, Jay L.

    2017-03-01

    A method is proposed to select and eject bunches of electrons or positrons from a high energy train of charged bunches, based on proven dielectric wakefield accelerator technology. The kicker structure, consisting of a pair of adjacent rectangular dielectric-lined waveguides, permits the coupling of the wakefield that is generated from a train of low-energy (˜6 MeV) "drive bunches" moving in one waveguide to the adjacent waveguide where a portion of a train of high energy "witness bunches" needs to be diverted. A very fast response time (˜1 ns) for bunch deflection is estimated, and a structure as short as 10-30 cm would suffice to impart to the diverted bunches a transverse kick of an interest to high-energy accelerator application, e.g. 150 keV/c. The witness bunch width must be less than 0.2 - 0.3 mm to have an emittance dilution that makes the deflected bunch suitable for e.g. FEL applications.

  18. Fabrication Technologies of the High Gradient Accelerator Structures at 100MV/M Range

    SciTech Connect

    Wang, Juwen; Lewandowski, James; Van Pelt, John; Yoneda, Charles; Gudkov, Boris; Riddone, Germana; Higo, Toshiyasu; Takatomi, Toshikazu; /KEK, Tsukuba

    2012-07-03

    A CERN-SLAC-KEK collaboration on high gradient X-band structure research has been established in order to demonstrate the feasibility of the CLIC baseline design for the main linac stably operating at more than 100 MV/m loaded accelerating gradient. Several prototype CLIC structures were successfully fabricated and high power tested. They operated at 105 MV/m with a breakdown rate that meets the CLIC linear collider specifications of < 5 x 10{sup -7}/pulse/m. This paper summarizes the fabrication technologies including the mechanical design, precision machining, chemical cleaning, diffusion bonding as well as vacuum baking and all related assembly technologies. Also, the tolerances control, tuning and RF characterization will be discussed.

  19. openSE: a Systems Engineering Framework Particularly Suited to Particle Accelerator Studies and Development Projects

    SciTech Connect

    Bonnal, P.; Féral, B.; Kershaw, K.; Nicquevert, B.; Baudin, M.; Lari, L.; Le Cardinal, J.

    2016-07-15

    Particle accelerator projects share many characteristics with industrial projects. However, experience has shown that best practice of industrial project management is not always well suited to particle accelerator projects. Major differences include the number and complexity of technologies involved, the importance of collaborative work, development phases that can last more than a decade, and the importance of telerobotics and remote handling to address future preventive and corrective maintenance requirements due to induced radioactivity, to cite just a few. The openSE framework it is a systems engineering and project management framework specifically designed for scientific facilities’ systems and equipment studies and development projects. Best practices in project management, in systems and requirements engineering, in telerobotics and remote handling and in radiation safety management were used as sources of inspiration, together with analysis of current practices surveyed at CERN, GSI and ESS.

  20. A linear electrostatic accelerator for education and advanced diagnostics development for OMEGA and the NIF

    NASA Astrophysics Data System (ADS)

    Sinenian, N.; Gatu Johnson, M.; Sio, H.; Waugh, C.; Orozco, D.; Penna, J.; Rinderknecht, H.; Rosenberg, M.; Zylstra, A.; Frenje, J.; Li, C. K.; Seguin, F.; Petrasso, R.; Ruiz, C.; Sangster, T.; Leeper, R.; Kilkenny, J.

    2013-10-01

    The MIT Linear Electrostatic Accelerator generates D-D and D-3He fusion products, which are used for development of nuclear diagnostics for OMEGA and the NIF. Fusion reaction rates of about 106 s-1 are routinely achieved, and fluence and energy of the fusion products have been accurately characterized. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) CVD-diamond-based bang time detector. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  1. Convergence acceleration for partitioned simulations of the fluid-structure interaction in arteries

    NASA Astrophysics Data System (ADS)

    Radtke, Lars; Larena-Avellaneda, Axel; Debus, Eike Sebastian; Düster, Alexander

    2016-06-01

    We present a partitioned approach to fluid-structure interaction problems arising in analyses of blood flow in arteries. Several strategies to accelerate the convergence of the fixed-point iteration resulting from the coupling of the fluid and the structural sub-problem are investigated. The Aitken relaxation and variants of the interface quasi-Newton -least-squares method are applied to different test cases. A hybrid variant of two well-known variants of the interface quasi-Newton-least-squares method is found to perform best. The test cases cover the typical boundary value problem faced when simulating the fluid-structure interaction in arteries, including a strong added mass effect and a wet surface which accounts for a large part of the overall surface of each sub-problem. A rubber-like Neo Hookean material model and a soft-tissue-like Holzapfel-Gasser-Ogden material model are used to describe the artery wall and are compared in terms of stability and computational expenses. To avoid any kind of locking, high-order finite elements are used to discretize the structural sub-problem. The finite volume method is employed to discretize the fluid sub-problem. We investigate the influence of mass-proportional damping and the material model chosen for the artery on the performance and stability of the acceleration strategies as well as on the simulation results. To show the applicability of the partitioned approach to clinical relevant studies, the hemodynamics in a pathologically deformed artery are investigated, taking the findings of the test case simulations into account.

  2. Priority research areas to accelerate the development of practical ultraconductive copper conductors

    SciTech Connect

    Lee, Dominic F.; Burwell, Malcolm; Stillman, H.

    2015-09-01

    This report documents the findings at an Ultraconductive Copper Strategy Meeting held on March 11, 2015 in Washington DC. The aim of this meeting was to bring together researchers of ultraconductive copper in the U.S. to identify and prioritize critical non-proprietary research activities that will enhance the understanding in the material and accelerate its development into practical conductors. Every effort has been made to ensure that the discussion and findings are accurately reported in this document.

  3. Design and Development Tools for the Systems Engineering Experience Accelerator. Volume 1

    DTIC Science & Technology

    2015-04-20

    INCOSE) 2012 International Symposium/European Conference on Systems Engineering (EUSEC), Rome , Italy, July 9-12. • Bodner, D., Wade, J., Squires, A...Editor in War Craft III. The map is named Defense of the Ancients (DotA) and has attracted millions of players using it for gaming worldwide. Since its... Rome , Italy. 7. Wade, J. P., "Design and Development Tools for the Systems Engineering Experience Accelerator," Systems Engineering Research

  4. Development of the C{sup 6+} laser ablation ion source for the KEK digital accelerator

    SciTech Connect

    Munemoto, Naoya; Takayama, Ken; Takano, Susumu; Okamura, Masahiro; Kumaki, Masahumi

    2014-02-15

    A laser ion source that provides a fully ionized carbon ion beam is under joint development at the High Energy Accelerator Research Organization and Brookhaven National Laboratory. Long-pulse (6 ns) and short-pulse (500 ps) laser systems were tested by using them to irradiate a graphite target. Notable differences between the systems were observed in these experiments. Preliminary experimental results, such as the charge-state spectrum, beam intensity, and stability, are discussed.

  5. High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods

    NASA Astrophysics Data System (ADS)

    Munroe, Brian J.; Cook, Alan M.; Shapiro, Michael A.; Temkin, Richard J.; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A. Dian; Tantawi, Sami G.; Marsh, Roark A.

    2013-01-01

    An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128MV/m at a breakdown probability of 3.6×10-3 per pulse per meter at a pulse length of 150 ns. The tested standing-wave structure was a single high-gradient cell with an inner row of elliptical rods and an outer row of round rods; the elliptical rods reduce the peak surface magnetic field by 20% and reduce the temperature rise of the rods during the pulse by several tens of degrees, while maintaining good damping and suppression of high order modes. When compared with a single-cell standing-wave undamped disk-loaded waveguide structure with the same iris geometry under test at the same conditions, the PBG-E structure yielded the same breakdown rate within measurement error. The PBG-E structure showed a greatly reduced breakdown rate compared with earlier tests of a PBG structure with round rods, presumably due to the reduced magnetic fields at the elliptical rods vs the fields at the round rods, as well as use of an improved testing methodology. A post-testing autopsy of the PBG-E structure showed some damage on the surfaces exposed to the highest surface magnetic and electric fields. Despite these changes in surface appearance, no significant change in the breakdown rate was observed in testing. These results demonstrate that PBG structures, when designed with reduced surface magnetic fields and operated to avoid extremely high pulsed heating, can operate at breakdown probabilities comparable to undamped disk-loaded waveguide structures and are thus viable for high-gradient accelerator applications.

  6. Structure of Developing Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Molinari, J. E.

    2006-12-01

    Considerable progress has been made in the numerical modeling of tropical cyclones. The very high resolution now routinely used in research models allows realistic simulation of eyewall structure and breakdown, vortex Rossby waves, and numerous other processes that were beyond the capability of previous generations of models. At least one aspect of tropical cyclones, however, has not been reproduced in the current generation of models: early development (or lack of development) during tropical depression and early tropical storm stages. During such times, vertical wind shear often plays a critical role. In this presentation, details of the structure of four tropical cyclones at early stages will be given: Claudette (2003), Danny (1997), Gabrielle (2001), and Edouard (2002). The first three contained intense vortices that formed within downshear convection. Deep-layer vertical wind shear ranged from 8-15 m/s in the storms. In Claudette, a hurricane formed that lasted only 6 hours. In Danny and Gabrielle, the downshear vortices became the new storm center. One became a hurricane and one did not. In Edouard, vertical shear was even larger. Convection fluctuated between downshear of the center and over the center, with analogous intensity changes. This behavior is known to forecasters, but the causes of such fluctuations remain uncertain. The evolving structure of these four storms will be shown, with emphasis on the variation of convection, equivalent potential temperature in the lower troposphere, and azimuthal asymmetries of wind and circulation. Contrast will be made between the structure of forming tropical cyclones in nature and those seen in mesoscale numerical models. Some remarks will be given on the key physical processes that must be simulated.

  7. Requirements and Development of an Acceleration Measurement System for International Space Station Microgravity Science Payloads

    NASA Technical Reports Server (NTRS)

    Sutliff, Thomas J.

    1997-01-01

    The International Space Station is being developed by NASA and international partners as a versatile user platform to allow long term on-orbit investigations of a variety of scientific and technology arenas. In particular, scientific studies are planned within a research class known as microgravity science in areas such as biotechnology, combustion, fluid physics, and materials sciences. An acceleration measurement system is in development to aid such research conducted in the on-orbit conditions of apparent weightlessness. This system provides a general purpose acceleration measurement capability in support of these payloads and investigators. Such capability allows for systematic study of scientific phenomena by obtaining information regarding the local accelerations present during experiment operations. Preparations for implementing this flight measurement system involves two distinct stages: requirements development prior to initiating the design activity, and the design activity itself. This paper defines the requirements definition approach taken, provides an overview of the results of the requirements phase, and outlines the initial design considerations being addressed for this measurement system. Some preliminary engineering approaches are also described.

  8. Beam Position Monitoring using the HOM-Signals from a Damped and Detuned Accelerating Structure

    SciTech Connect

    Dobert, S; Adolphsen, C.; Jones, R.; Lewandowski, J.; Li, Z.; Pivi, M.; Wang, J.; Higo, T.; /KEK, Tsukuba

    2005-05-17

    The Next and Global Linear Collider (NLC/GLC) designs require precision alignment of the beam in the accelerator structures to reduce short range wakefields. The moderately damped and detuned structures themselves provide suitable higher order mode (HOM) signals to measure this alignment. The modes in the lowest dipole band, whose frequencies range from 14-16 GHz, provide the strongest signals. To determine the position resolution they provide, an NLC/GLC prototype structure that was installed in the ASSET facility of the SLAC Linac was instrumented to downmix and digitize these signals. The beam position within the structure was determined by simultaneously measuring the signals at three frequencies (14.3, 15, 15.7 GHz) corresponding to modes localized at the beginning, the middle and the end of the 60 cm long structure. A resolution of 1 micron was achieved even with 28 dB signal attenuation, which is better than the 5 micron resolution required for the NLC/GLC.

  9. Acceleration Data Reveal Highly Individually Structured Energetic Landscapes in Free-Ranging Fishers (Pekania pennanti)

    PubMed Central

    Scharf, Anne K.; LaPoint, Scott; Wikelski, Martin; Safi, Kamran

    2016-01-01

    Investigating animal energy expenditure across space and time may provide more detailed insight into how animals interact with their environment. This insight should improve our understanding of how changes in the environment affect animal energy budgets and is particularly relevant for animals living near or within human altered environments where habitat change can occur rapidly. We modeled fisher (Pekania pennanti) energy expenditure within their home ranges and investigated the potential environmental and spatial drivers of the predicted spatial patterns. As a proxy for energy expenditure we used overall dynamic body acceleration (ODBA) that we quantified from tri-axial accelerometer data during the active phases of 12 individuals. We used a generalized additive model (GAM) to investigate the spatial distribution of ODBA by associating the acceleration data to the animals' GPS-recorded locations. We related the spatial patterns of ODBA to the utilization distributions and habitat suitability estimates across individuals. The ODBA of fishers appears highly structured in space and was related to individual utilization distribution and habitat suitability estimates. However, we were not able to predict ODBA using the environmental data we selected. Our results suggest an unexpected complexity in the space use of animals that was only captured partially by re-location data-based concepts of home range and habitat suitability. We suggest future studies recognize the limits of ODBA that arise from the fact that acceleration is often collected at much finer spatio-temporal scales than the environmental data and that ODBA lacks a behavioral correspondence. Overcoming these limits would improve the interpretation of energy expenditure in relation to the environment. PMID:26840399

  10. The trade-off between maturation and growth during accelerated development in frogs.

    PubMed

    Mueller, Casey A; Augustine, Starrlight; Kooijman, Sebastiaan A L M; Kearney, Michael R; Seymour, Roger S

    2012-09-01

    Developmental energetics are crucial to a species' life history and ecology but are poorly understood from a mechanistic perspective. Traditional energy and mass budgeting does not distinguish between costs of growth and maturation, making it difficult to account for accelerated development. We apply a metabolic theory that uniquely considers maturation costs (Dynamic Energy Budget theory, DEB) to interpret empirical data on the energetics of accelerated development in amphibians. We measured energy use until metamorphosis in two related frogs, Crinia georgiana and Pseudophryne bibronii. Mass and energy content of fresh ova were comparable between the species. However, development to metamorphosis was 1.7 times faster in C. georgiana while P. bibronii produced nine times the dry biomass at metamorphosis and had lower mass-specific oxygen requirements. DEB theory explained these patterns through differences in ontogenetic energy allocation to maturation. P. bibronii partitioned energy in the same (constant) way throughout development whereas C. georgiana increased the fraction of energy allocated to maturation over growth between hatching and the onset of feeding. DEB parameter estimation for additional, direct-developing taxa suggests that a change in energy allocation during development may result from a selective pressure to increase development rate, and not as a result of development mode.

  11. SOFIA-EXES: Probing the Thermal Structure of M Supergiant Wind Acceleration Zones

    NASA Astrophysics Data System (ADS)

    Harper, Graham M.; O'Gorman, Eamon; Guinan, Edward F.; EXES Instrument Team, EXES Science Team

    2016-01-01

    There is no standard model for mass loss from cool evolved stars, particularly for non-pulsating giants and supergiants. For the early-M supergiants, radiation pressure, convective ejections, magnetic fields, and Alfven waves have all been put forward as potential mass loss mechanisms. A potential discriminator between these ideas is the thermal structure resulting from the heating-cooling balance in the acceleration zone - the most important region to study mass loss physics.We present mid-IR [Fe II] emission line profiles of Betelgeuse and Antares obtained with NASA-DLR SOFIA-EXES and NASA IRTF-TEXES that were obtained as part of a GO program (Harper: Cycle 2-0004) and EXES instrument commissioning observations. The intra-term transitions sample a range of excitation conditions, Texc=540K, 3,400K, and 11,700K, i.e., from the warm chromospheric plasma, that also emits in the cm-radio and ultraviolet, to the cold inner circumstellar envelope. The spectrally-resolved profiles, when combined with VLA cm-radio observations, provide new constraints on the temperature and flow velocity in the outflow accelerating region. The semi-empirical energy balance can be used to test theoretical predictions of wind heating.

  12. Attenuated hypothalamic-pituitary-adrenal axis functioning predicts accelerated pubertal development in girls 1 year later.

    PubMed

    Saxbe, Darby E; Negriff, Sonya; Susman, Elizabeth J; Trickett, Penelope K

    2015-08-01

    Accelerated pubertal development has been linked to adverse early environments and may heighten subsequent mental and physical health risks. Hypothalamic-pituitary-adrenal axis functioning has been posited as a mechanism whereby stress may affect pubertal development, but the literature lacks prospective tests of this mechanism. The current study assessed 277 youth (M = 10.84 years, SD = 1.14), 138 boys and 139 girls, who reported on their pubertal development and underwent the Trier Social Stress Test for Children at baseline and returned to the laboratory approximately 1 year later (M = 1.12 years, range = 0.59-1.98 years). For girls, lower cortisol area under the curve (with respect to ground) at Time 1 predicted more advanced pubertal development at Time 2, controlling for Time 1 pubertal development. This association persisted after additional covariates including age, body mass index, race, and maltreatment history were introduced, and was driven by adrenal rather than gonadal development. Cortisol was not linked to boys' subsequent pubertal development, and no interaction by gender or by maltreatment appeared. These results suggest that attenuated cortisol, reported in other studies of children exposed to early adversity, may contribute to accelerated pubertal tempo in girls.

  13. New Accelerated Testing and Lifetime Modeling Methods Promise Faster Development of More Durable MEAs

    SciTech Connect

    Pierpont, D. M.; Hicks, M. T.; Turner, P. L.; Watschke, T. M.

    2005-11-01

    For the successful commercialization of fuel cell technology, it is imperative that membrane electrode assembly (MEA) durability is understood and quantified. MEA lifetimes of 40,000 hours remain a key target for stationary power applications. Since it is impractical to wait 40,000 hours for durability results, it is critical to learn as much information as possible in as short a time period as possible to determine if an MEA sample will survive past its lifetime target. Consequently, 3M has utilized accelerated testing and statistical lifetime modeling tools to develop a methodology for evaluating MEA lifetime. Construction and implementation of a multi-cell test stand have allowed for multiple accelerated tests and stronger statistical data for learning about durability.

  14. Selection of flowing liquid lead target structural materials for accelerator driven transmutation applications

    NASA Astrophysics Data System (ADS)

    Park, John J.; Buksa, John J.

    1995-09-01

    The beam entry window and container for a liquid lead spallation target will be exposed to high fluxes of protons and neutrons that are both higher in magnitude and energy than have been experienced in proton accelerators and fission reactors, as well as in a corrosive environment. The structural material of the target should have a good compatibility with liquid lead, a sufficient mechanical strength at elevated temperatures, a good performance under an intense irradiation environment, and a low neutron absorption cross section; these factors have been used to rank the applicability of a wide range of materials for structural containment. Nb-1Zr has been selected for use as the structural container for the LANL ABC/ATW molten lead target. Corrosion and mass transfer behavior for various candidate structural materials in liquid lead are reviewed, together with the beneficial effects of inhibitors and various coatings to protect substrate against liquid lead corrosion. Mechanical properties of some candidate materials at elevated temperatures and the property changes resulting from 800 MeV proton irradiation are also reviewed.

  15. Recent developments in rf superconductivity for high-brightness and high-gradient ion beam accelerators

    SciTech Connect

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

    1992-02-01

    Recent progress in on-going development program leading to the design of superconducting continuous-wave (cw) linear accelerators for high-brightness ion beams is reviewed. A new spoke-resonator geometry incorporating a half-wavelength resonant line was fabricated and tested. This geometry serves as the basis for the constituent cavities of a superconducting section being designed for high-current testing with a deuterium beam. Considerable progress has been made in the design of this section. A multi-phased program leading to the development of a superconducting radio-frequency quadrupole (SCRFQ) has been initiated. Design considerations and test results from the various activities are presented.

  16. Recent developments in rf superconductivity for high-brightness and high-gradient ion beam accelerators

    SciTech Connect

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

    1992-01-01

    Recent progress in on-going development program leading to the design of superconducting continuous-wave (cw) linear accelerators for high-brightness ion beams is reviewed. A new spoke-resonator geometry incorporating a half-wavelength resonant line was fabricated and tested. This geometry serves as the basis for the constituent cavities of a superconducting section being designed for high-current testing with a deuterium beam. Considerable progress has been made in the design of this section. A multi-phased program leading to the development of a superconducting radio-frequency quadrupole (SCRFQ) has been initiated. Design considerations and test results from the various activities are presented.

  17. Education and Skills for Development in South Africa: Reflections on the Accelerated and Shared Growth Initiative for South Africa

    ERIC Educational Resources Information Center

    McGrath, S.; Akoojee, Salim

    2007-01-01

    In July 2005, President Mbeki announced the launch of the Accelerated and Shared Growth Initiative for South Africa (AsgiSA), a new development strategy designed to help the South African state meet the ANC's 2004 election pledges, namely: (1) halve unemployment; (2) halve poverty; (3) accelerate employment equity; and (4) improve broad-based…

  18. Determination of molecular-ion structures through the use of accelerated beams

    SciTech Connect

    Gemmell, D.S.

    1987-01-01

    In this talk we report on recent research on molecular-ion structures using fast molecular-ion beams provided by Argonne's 5-MV Dynamitron accelerator. The method has become known as the ''Coulomb-explosion'' technique. When molecular-ion projectiles travelling at velocities of a few percent of the velocity of light strike a foil, the electrons that bind the molecular projectiles are almost always totally stripped off within the first few Angstroms of penetration into the solid target. This leaves a cluster of bare (or nearly bare) nuclei which separate rapidly as a result of their mutual Coulomb repulsion. This violent dissociation process in which the initial electrostatic potential energy is converted into kinetic energy of relative motion in the center-of-mass, has been termed a ''Coulomb explosion.'' 4 refs., 2 figs.

  19. Influence of solidification accelerators on structure formation of anhydrite-containing binders

    NASA Astrophysics Data System (ADS)

    Anikanova, L.; Volkova, O.; Kudyakov, A.; Sarkisov, Y.; Tolstov, D.

    2016-01-01

    The article presents results of scientific analysis of chemical additives influence on acid fluoride binder. It was found that the influence of sulfate nature additives on the process of hydration and solidification of the binder is similar to influence of additives on indissoluble anhydrite. Additives with SO42- anion NO- are more efficient. The mentioned additives according to accelerating effect belong to the following succession: K2SO4 > Na2SO4 > FeSO4 > MgSO4. Facilitation of the process of hydration and solidification of the binder, increase in density and durability of the binder (32 MPa) is to the greatest extent achieved with the introduction of 2% sodium sulfate additive of the binder's mass into the composition of the binder along with the ultrasonic treatment of water solution. Directed crystal formation process with healing of porous structure by new growths presented as calcium sulfate dehydrate and hydroglauberite provides positive effect.

  20. Structure Loaded Vacuum Laser-Driven Particle Acceleration Experiments at SLAC

    SciTech Connect

    Plettner, T.; Byer, R.L.; Colby, E.R.; Cowan, B.M.; Ischebeck, R.; McGuinness, C.; Lincoln, M.R.; Sears, C.M.; Siemann, R.H.; Spencer, J.E.; /SLAC /Stanford U., Phys. Dept.

    2007-04-09

    We present an overview of the future laser-driven particle acceleration experiments. These will be carried out at the E163 facility at SLAC. Our objectives include a reconfirmation of the proof-of-principle experiment, a staged buncher laser-accelerator experiment, and longer-term future experiments that employ dielectric laser-accelerator microstructures.

  1. Accelerating vaccine development and deployment: report of a Royal Society satellite meeting

    PubMed Central

    Bregu, Migena; Draper, Simon J.; Hill, Adrian V. S.; Greenwood, Brian M.

    2011-01-01

    The Royal Society convened a meeting on the 17th and 18th November 2010 to review the current ways in which vaccines are developed and deployed, and to make recommendations as to how each of these processes might be accelerated. The meeting brought together academics, industry representatives, research sponsors, regulators, government advisors and representatives of international public health agencies from a broad geographical background. Discussions were held under Chatham House rules. High-throughput screening of new vaccine antigens and candidates was seen as a driving force for vaccine discovery. Multi-stakeholder, small-scale manufacturing facilities capable of rapid production of clinical grade vaccines are currently too few and need to be expanded. In both the human and veterinary areas, there is a need for tiered regulatory standards, differentially tailored for experimental and commercial vaccines, to allow accelerated vaccine efficacy testing. Improved cross-fertilization of knowledge between industry and academia, and between human and veterinary vaccine developers, could lead to more rapid application of promising approaches and technologies to new product development. Identification of best-practices and development of checklists for product development plans and implementation programmes were seen as low-cost opportunities to shorten the timeline for vaccine progression from the laboratory bench to the people who need it. PMID:21893549

  2. Accelerated development of CuSbS2 thin film photovoltaic device prototypes

    SciTech Connect

    Welch, Adam W.; Baranowski, Lauryn L.; Zawadzki, Pawel; DeHart, Clay; Johnston, Steve; Lany, Stephan; Wolden, Colin A.; Zakutayev, Andriy

    2016-02-03

    Development of alternative thin film photovoltaic technologies is an important research topic because of the potential of low-cost, high-efficiency solar cells to produce terawatt levels of clean power. However, this development of unexplored yet promising absorbers can be hindered by complications that arise during solar cell fabrication. Here, a high-throughput combinatorial method is applied to accelerate development of photovoltaic devices, in this case, using the novel CuSbS2 absorber via a newly developed three-stage self-regulated growth process to control absorber purity and orientation. Photovoltaic performance of the absorber, using the typical substrate CuInxGa1 - xSe2 (CIGS) device architecture, is explored as a function of absorber quality and thickness using a variety of back contacts. This study yields CuSbS2 device prototypes with ~1% conversion efficiency, suggesting that the optimal CuSbS2 device fabrication parameters and contact selection criteria are quite different than for CIGS, despite the similarity of these two absorbers. The CuSbS2 device efficiency is at present limited by low short-circuit current because of bulk recombination related to defects, and a small open-circuit voltage because of a theoretically predicted cliff-type conduction band offset between CuSbS2 and CdS. Overall, these results illustrate both the potential and limits of combinatorial methods to accelerate the development of thin film photovoltaic devices using novel absorbers.

  3. Performance and Environmental Test Results of the High Voltage Hall Accelerator Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Shastry, Rohit; Pinero, Luis; Peterson, Todd; Mathers, Alex

    2012-01-01

    NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.

  4. Vocal sac development and accelerated sexual maturity in the lesser swimming frog, Pseudis minuta (Anura, Hylidae).

    PubMed

    Goldberg, Javier; Barrasso, Diego A; Agostini, M Gabriela; Quinzio, Silvia

    2016-12-01

    Sexual maturity involves the differentiation of the reproductive system, the maturation of germ cells, and the development of secondary sexual characteristics. Even though this topic has received much attention, little is known about the sequence of events that encompass reproductive maturation in anurans and what it could reveal about the developmental basis of life cycle evolution. The discovery of froglets of Pseudis minuta with incipient vocal sacs calling in breeding pools alongside several larger adult specimens with fully developed vocal sacs raised the question of the timing of sexual maturity in this species. Here we describe the sequence and timing of differentiation, development and maturation of the vocal sac apparatus and the testes in P. minuta (Anura, Hylidae), in order to establish a timeline of events leading to sexual maturity. Differentiation of the vocal sac apparatus begins at the final metamorphic stages, earlier than reported for other species, and the vocal sac acquires its final shape during the early postmetamorphic period. These modifications occur after gonadal differentiation, which begins early during the larval period and proceeds with a highly accelerated rate of development (e.g., secondary spermatids appear well before metamorphic climax), a situation reported previously for other anuran species only in the genus Pseudis. These results, together with a skeletochronological analysis showing that some calling specimens presented no lines of arrested growth, indicate acceleration in the timing of sexual maturity in Pseudis, and raise questions about the interdependence/decoupling during the development of the different components involved in reaching the adult stage.

  5. Using Uncertainty Analysis to Guide the Development of Accelerated Stress Tests (Presentation)

    SciTech Connect

    Kempe, M.

    2014-03-01

    Extrapolation of accelerated testing to the long-term results expected in the field has uncertainty associated with the acceleration factors and the range of possible stresses in the field. When multiple stresses (such as temperature and humidity) can be used to increase the acceleration, the uncertainty may be reduced according to which stress factors are used to accelerate the degradation.

  6. Teacher Attitudes toward Subject-Specific Acceleration: Instrument Development and Validation

    ERIC Educational Resources Information Center

    Rambo, Karen E.; McCoach, D. Betsy

    2012-01-01

    Despite the research supporting acceleration, some teachers are still hesitant to recommend acceleration for advanced students. The Teacher Attitudes Toward Subject-Specific Acceleration (TATSSA) instrument was designed to uncover the factors that influence teacher decisions to recommend students for subject-specific acceleration. First, we…

  7. WInd-and-react Bi-2212 coil development for accelerator magnets

    SciTech Connect

    Godeke, A.; Acosta, P.; Cheng, D.; Dietderich, D. R.; Mentink, M. G. T.; Prestemon, S. O.; Meinesz, M.; Hong, S.; Huang, Y.; Miao, H.; Parrell, J.; Sabbi, G.L.

    2009-10-13

    Sub-scale coils are being manufactured and tested at Lawrence Berkeley National Laboratory in order to develop wind-and-react Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} (Bi-2212) magnet technology for future graded accelerator magnet use. Previous Bi-2212 coils showed significant leakage of the conductors core constituents to the environment, which can occur during the partial melt reaction around 890 C in pure oxygen. The main origin of the observed leakage is intrinsic leakage of the wires, and the issue is therefore being addressed at the wire manufacturing level. We report on further compatibility studies, and the performance of new sub-scale coils that were manufactured using improved conductors. These coils exhibit significantly reduced leakage, and carry currents that are about 70% of the witness wire critical current (I{sub c}). The coils demonstrate, for the first time, the feasibility of round wire Bi-2212 conductors for accelerator magnet technology use. Successful high temperature superconductor coil technology will enable the manufacture of graded accelerator magnets that can surpass the, already closely approached, intrinsic magnetic field limitations of Nb-based superconducting magnets.

  8. Development of vacuum arc ion sources for heavy ion accelerator injectors and ion implantation technology (invited)

    NASA Astrophysics Data System (ADS)

    Oks, Efim M.

    1998-02-01

    The status of experimental research and ongoing development and upgrade of MEVVA-type ion sources over the last two years since the previous ICIS-95 is reviewed. There are two main application fields for this ion source: heavy ion accelerators and material surface implantation technology. For particle accelerator ion injection to accelerators it is important to enhance the fractions of multiply charged ions in the ion beam as well as controlling the charge state distribution, and to improve of beam current stability (i.e., to minimize the beam noise) and pulse-to-pulse reproducibility. For ion implantation application we need to increase both the implantation dose rate and the source lifetime (between required maintenance downtime) as well as making this kind of source more reliable and of yet low cost. Most of experimental results reported on here have been obtained in a collaborative program between research groups LBNL (Berkeley, USA), GSI (Darmstadt, Germany), HCEI (Tomsk, Russia), and other important contributions have been made by the groups at (BNU, Beijing, China), EDU (Izmir, Turkey), and elsewhere.

  9. 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.

  10. Track Structure and the Biological Effectiveness of Accelerated Particles for the Induction of Chromosome Damage

    NASA Technical Reports Server (NTRS)

    George, K.; Hada, M.; Chappell, L.; Cucinotta, F. A.

    2011-01-01

    Track structure models predict that at a fixed value of LET, particles with lower charge number, Z will have a higher biological effectiveness compared to particles with a higher Z. In this report we investigated how track structure effects induction of chromosomal aberration in human cells. Human lymphocytes were irradiated in vitro with various energies of accelerated iron, silicon, neon, or titanium ions and chromosome damage was assessed in using three color FISH chromosome painting in chemically induced PCC samples collected a first cell division post irradiation. The LET values for these ions ranged from 30 to195 keV/micron. Of the particles studied, Neon ions have the highest biological effectiveness for induction of total chromosome damage, which is consistent with track structure model predictions. For complex-type exchanges 64 MeV/ u Neon and 450 MeV/u Iron were equally effective and induced the most complex damage. In addition we present data on chromosomes exchanges induced by six different energies of protons (5 MeV/u to 2.5 GeV/u). The linear dose response term was similar for all energies of protons suggesting that the effect of the higher LET at low proton energies is balanced by the production of nuclear secondaries from the high energy protons.

  11. CO2 enrichment accelerates successional development of an understory plant community

    SciTech Connect

    Souza, Lara; Belote, R. Travis Travis; Kardol, Paul; Weltzin, Jake; Norby, Richard J

    2010-01-01

    Rising concentrations of atmospheric carbon dioxide ([CO{sub 2}]) may influence forest successional development and species composition of understory plant communities by altering biomass production of plant species of functional groups. Here, we describe how elevated [CO{sub 2}] (eCO{sub 2}) affects aboveground biomass within the understory community of a temperate deciduous forest at the Oak Ridge National Laboratory sweetgum (Liquidambar styraciflua) free-air carbon dioxide enrichment (FACE) facility in eastern Tennessee, USA. We asked if (i) CO{sub 2} enrichment affected total understory biomass and (ii) whether total biomass responses could be explained by changes in understory species composition or changes in relative abundance of functional groups through time. The FACE experiment started in 1998 with three rings receiving ambient [CO{sub 2}] (aCO{sub 2}) and two rings receiving eCO{sub 2}. From 2001 to 2003, we estimated species-specific, woody versus herbaceous and total aboveground biomass by harvesting four 1 x 0.5-m subplots within the established understory plant community in each FACE plot. In 2008, we estimated herbaceous biomass as previously but used allometric relationships to estimate woody biomass across two 5 x 5-m quadrats in each FACE plot. Across years, aboveground biomass of the understory community was on average 25% greater in eCO{sub 2} than in aCO{sub 2} plots. We could not detect differences in plant species composition between aCO{sub 2} and eCO{sub 2} treatments. However, we did observe shifts in the relative abundance of plant functional groups, which reflect important structural changes in the understory community. In 2001-03, little of the understory biomass was in woody species; herbaceous species made up 94% of the total understory biomass across [CO{sub 2}] treatments. Through time, woody species increased in importance, mostly in eCO{sub 2}, and in 2008, the contribution of herbaceous species to total understory biomass was

  12. Electron acceleration at localized wave structures in the solar corona (German Title: Elektronenbeschleunigung an lokalen Wellenstrukturen in der Sonnenkorona)

    NASA Astrophysics Data System (ADS)

    Miteva, Rositsa Stoycheva

    2007-07-01

    Our dynamic Sun manifests its activity by different phenomena: from the 11-year cyclic sunspot pattern to the unpredictable and violent explosions in the case of solar flares. During flares, a huge amount of the stored magnetic energy is suddenly released and a substantial part of this energy is carried by the energetic electrons, considered to be the source of the nonthermal radio and X-ray radiation. One of the most important and still open question in solar physics is how the electrons are accelerated up to high energies within (the observed in the radio emission) short time scales. Because the acceleration site is extremely small in spatial extent as well (compared to the solar radius), the electron acceleration is regarded as a local process. The search for localized wave structures in the solar corona that are able to accelerate electrons together with the theoretical and numerical description of the conditions and requirements for this process, is the aim of the dissertation. Two models of electron acceleration in the solar corona are proposed in the dissertation: I. Electron acceleration due to the solar jet interaction with the background coronal plasma (the jet--plasma interaction) A jet is formed when the newly reconnected and highly curved magnetic field lines are relaxed by shooting plasma away from the reconnection site. Such jets, as observed in soft X-rays with the Yohkoh satellite, are spatially and temporally associated with beams of nonthermal electrons (in terms of the so-called type III metric radio bursts) propagating through the corona. A model that attempts to give an explanation for such observational facts is developed here. Initially, the interaction of such jets with the background plasma leads to an (ion-acoustic) instability associated with growing of electrostatic fluctuations in time for certain range of the jet initial velocity. During this process, any test electron that happen to feel this electrostatic wave field is drawn to co

  13. Structure of a strong supernova shock wave and rapid electron acceleration confined in its transition region

    SciTech Connect

    Shimada, N.; Hoshino, M.; Amano, T.

    2010-03-15

    A new rapid energization process within a supernova shock transition region (STR) is reported by utilizing numerical simulation. Although the scale of a STR as a main dissipation region is only several hundreds of thousands of kilometers, several interesting structures are found relating to the generation of a root of the energetic particles. The nonlinear evolution of plasma instabilities leads to a dynamical change in the ion phase space distribution, which associates with change in the field properties. As a result, different types of large-amplitude field structures appear. One is the leading wave packet, and another is a series of magnetic solitary humps. Each field structure has a microscopic scale (that is, the ion inertia length). Through the multiple nonlinear scattering between these large-amplitude field structures, electrons are accelerated directly. Within a STR, quick thermalization realizes energy equipartition between the ion and electron; hot electrons play an important role in keeping these large-amplitude field structures on the ion-acoustic mode. The hot electron shows non-Maxwellian distribution and could be the seed of further nonthermal population. The 'shock system', where fresh incoming and reflected ions are supplied constantly, play an essential role in our result. With a perpendicular shock geometry, the maximum energy of the electron is estimated by equating a width of the STR to a length of the Larmor radius of the energetic electron. Under some realistic condition of M{sub A}=170 and omega{sub pe}/OMEGA{sub ce}=120, maximum energy is estimated to be approx10 MeV at an instant only within the STR.

  14. VLA Observations of ζ Aurigae: Confirmation of the Slow Acceleration Wind Density Structure

    NASA Astrophysics Data System (ADS)

    Harper, Graham M.; Brown, Alexander; Bennett, Philip D.; Baade, Robert; Walder, Rolf; Hummel, Christian A.

    2005-02-01

    Studies of the winds from single K and early M evolved stars indicate that these flows typically reach a significant fraction of their terminal velocity within the first couple of stellar radii. The most detailed spatially resolved information of the extended atmospheres of these spectral types comes from the ζ Aur eclipsing binaries. However, the wind acceleration inferred for the evolved primaries in these systems appears significantly slower than for stars of similar spectral type. Since there are no successful theories for mass loss from K and early M evolved stars, it is important to place strong empirical constraints on potential models and determine whether this difference in acceleration is real or an artifact of the analyses. We have undertaken a radio continuum monitoring study of ζ Aurigae (K4 Ib + B5 V) using the Very Large Array to test the wind density model of Baade et al. that is based on Hubble Space Telescope (HST) Goddard High Resolution Spectrograph ultraviolet spectra. ζ Aur was monitored at centimeter wavelengths over a complete orbital cycle, and flux variations during the orbit are found to be of similar magnitude to variations at similar orbital phases in the adjacent orbit. During eclipse, the flux does not decrease, showing that the radio emission originates from a volume substantially larger than R3K~(150Rsolar)3 surrounding the B star. Using the one-dimensional density model of the K4 Ib primary's wind derived from HST spectral line profile modeling and electron temperature estimates from previous optical and new HST studies, we find that the predicted radio fluxes are consistent with those observed. Three-dimensional hydrodynamic simulations indicate that the accretion flow perturbations near the B star do not contribute significantly to the total radio flux from the system, consistent with the radio eclipse observations. Our radio observations confirm the slow wind acceleration for the evolved K4 Ib component. ζ Aur's velocity

  15. UCLA accelerator research and development. Progress report, [November 1, 1991--July 31, 1992

    SciTech Connect

    Cline, D.B.

    1992-09-01

    This progress report covers work supported by the above DOE grant over the period November 1, 1991 to July 31, 1992. The work is a program of experimental and theoretical studies in advanced particle accelerator research and development for high energy physics applications. The program features research at particle beam facilities in the United States and includes research on novel high power sources, novel focussing systems (e.g. plasma lens), beam monitors, novel high brightness, high current gun systems, and novel flavor factories in particular the {phi} Factory.

  16. Application of Plasma Waveguides to High Energy Accelerators

    SciTech Connect

    Milchberg, Howard

    2016-07-01

    This grant supported basic experimental, theoretical and computer simulation research into developing a compact, high pulse repetition rate laser accelerator using the direct laser acceleration mechanism in plasma-based slow wave structures.

  17. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate ('dynamic fatigue') testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rate in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  18. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate (dynamic fatigue) testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rates in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  19. Zinc promotes clot stability by accelerating clot formation and modifying fibrin structure.

    PubMed

    Henderson, Sara J; Xia, Jing; Wu, Huayin; Stafford, Alan R; Leslie, Beverly A; Fredenburgh, James C; Weitz, David A; Weitz, Jeffrey I

    2016-03-01

    Zinc released from activated platelets binds fibrin(ogen) and attenuates fibrinolysis. Although zinc also affects clot formation, the mechanism and consequences are poorly understood. To address these gaps, the effect of zinc on clot formation and structure was examined in the absence or presence of factor (F) XIII. Zinc accelerated a) plasma clotting by 1.4-fold, b) fibrinogen clotting by 3.5- and 2.3-fold in the absence or presence of FXIII, respectively, c) fragment X clotting by 1.3-fold, and d) polymerisation of fibrin monomers generated with thrombin or batroxobin by 2.5- and 1.8-fold, respectively. Whereas absorbance increased up to 3.3-fold when fibrinogen was clotted in the presence of zinc, absorbance of fragment X clots was unaffected by zinc, consistent with reports that zinc binds to the αC-domain of fibrin(ogen). Scanning electron microscopic analysis revealed a two-fold increase in fibre diameter in the presence of zinc and in permeability studies, zinc increased clot porosity by 30-fold with or without FXIII. Whereas FXIII increased clot stiffness from 128 ± 19 Pa to 415 ± 27 Pa in rheological analyses, zinc reduced clot stiffness by 10- and 8.5-fold in the absence and presence of FXIII, respectively. Clots formed in the presence of zinc were more stable and resisted rupture with or without FXIII. Therefore, zinc accelerates clotting and reduces fibrin clot stiffness in a FXIII-independent manner, suggesting that zinc may work in concert with FXIII to modulate clot strength and stability.

  20. Neoadjuvant paradigm for accelerated drug development: an ideal model in bladder cancer.

    PubMed

    Chism, David D; Woods, Michael E; Milowsky, Matthew I

    2013-01-01

    Neoadjuvant cisplatin-based combination chemotherapy for muscle-invasive bladder cancer (MIBC) has been shown to confer a survival advantage in two randomized clinical trials and a meta-analysis. Despite level 1 evidence supporting its benefit, utilization remains dismal with nearly one-half of patients ineligible for cisplatin-based therapy because of renal dysfunction, impaired performance status, and/or coexisting medical problems. This situation highlights the need for the development of novel therapies for the management of MIBC, a disease with a lethal phenotype. The neoadjuvant paradigm in bladder cancer offers many advantages for accelerated drug development. First, there is a greater likelihood of successful therapy at an earlier disease state that may be characterized by less genomic instability compared with the metastatic setting, with an early readout of activity with results determined in months rather than years. Second, pre- and post-treatment tumor tissue collection in patients with MIBC is performed as the standard of care without the need for research-directed biopsies, allowing for the ability to perform important correlative studies and to monitor tumor response to therapy in "real time." Third, pathological complete response (pT0) predicts for improved outcome in patients with MIBC. Fourth, there is a strong biological rationale with rapidly accumulating evidence for actionable targets in bladder cancer. This review focuses on the neoadjuvant paradigm for accelerated drug development using bladder cancer as the ideal model.

  1. Analysis of a Symmetric Terahertz Dielectric-Lined Rectangular Structure for High Gradient Acceleration

    SciTech Connect

    Marshall, T. C.; Sotnikov, G. V.; Shchelkunov, S. V.; Hirshfield, J. L.

    2009-01-22

    We study, using computational methods based on analytic theory as well as a PIC code, the wakefields set up in a seven-zone symmetric rectangular THZ structure, and find that for overall transverse x/y dimensions 2.121 mmx0.6 mm, two 5-GeV drive bunches (3 nC, with x/y/z dimensions 0.3/0.3/0.12 mm{sup 3} as available at SLAC) will set up an axial wakefield {approx}350 MV/m in the witness channel, with a transformer ratio {approx}18-20. The symmetry of the structure ensures not only that small transverse forces are imposed on the witness bunch, but also that the two components of transverse force are equal and opposite at the bunch location so as to enable dynamical stabilization in an accelerator comprising many modules. Transverse forces on the drive bunch tails may allow bunches to move {approx}0.5-1 m without suffering excessive erosion.

  2. Development of superplastic structural ceramics

    SciTech Connect

    Chen, I.W.; Xue, L.A. )

    1990-09-01

    Superplastic structural ceramics (Y-TZP, Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4}, and their composites) that can withstand biaxial stretching to large strains have been developed. Microstructural design of these ceramics first requires an ultrafine grain size that is stable against coarsening during sintering and deformation. A low sintering temperature is a necessary, but not a sufficient, condition for achieving the required microstructure. In many cases, the selection of an appropriate phase, such as tetragonal phase in zirconia or {alpha} phase in silicon nitride, which is resistant to grain growth, is crucial. The use of sintering aids and grain-growth inhibitors, particularly those that segregate to the grain boundaries, can be beneficial. Second-phase particles are especially effective in suppressing static and dynamic grain growth. Another concern is to maintain an adequate grain-boundary cohesive strength, relative to the flow stress, to mitigate cavitation or grain-boundary cracking during large strain deformation. Existing evidence suggests that a lower grain-boundary energy is instrumental in achieving this objective.

  3. Effect of gravitational acceleration, hypokinesia and hypodynamia on the structure of the intestinal vascular bed

    NASA Technical Reports Server (NTRS)

    Nikitin, M. V.

    1980-01-01

    A series of experiments comparing single and combined effects of hypokinesia and gravitational acceleration on morphology of intestinal blood vessels are discussed. Results indicate that hypokinesia has a whole body nonspecific effect reflected even in an organ whose activity shows little or no change due to hypokinesia. In early hypokinetic stages blood redistribution caused anorexia, intestinal atonia, and secretory disruption. Destructive changes from further exposure include aneurisms, varicoses, extravascular movement of blood elements, and vascular wall muscle fiber degeneration. The effect of acceleration is greatest in the ventrodorsal direction. Changes due to acceleration then hypokinesia are like those due to hypokinesia alone; changes due to acceleration before and after hypokinesia are like those due to acceleration. Adaptation raises acceleration tolerance but the effects do not survive four-week hypokinesia.

  4. Surface water geochemical and isotopic variations in an area of accelerating Marcellus Shale gas development.

    PubMed

    Pelak, Adam J; Sharma, Shikha

    2014-12-01

    Water samples were collected from 50 streams in an area of accelerating shale gas development in the eastern U.S.A. The geochemical/isotopic characteristics show no correlation with the five categories of Marcellus Shale production. The sub-watersheds with the greatest density of Marcellus Shale development have also undergone extensive coal mining. Hence, geochemical/isotopic compositions were used to understand sources of salinity and effects of coal mining and shale gas development in the area. The data indicates that while some streams appear to be impacted by mine drainage; none appear to have received sustained contribution from deep brines or produced waters associated with shale gas production. However, it is important to note that our interpretations are based on one time synoptic base flow sampling of a few sampling stations and hence do account potential intermittent changes in chemistry that may result from major/minor spills or specific mine discharges on the surface water chemistry.

  5. Development of an accelerated leach test(s) for low-level waste forms

    SciTech Connect

    Dougherty, D.R.; Fuhrmann, M.; Colombo, P.

    1985-01-01

    An accelerated leach test(s) is being developed to predict long-term leaching behavior of low-level radioactive waste (LLW) forms in their disposal environments. As necessary background, a literature survey of reported leaching mechanisms, available mathematical models and factors that affect leaching of LLW forms has been compiled. Mechanisms which have been identified include diffusion, dissolution, ion exchange, corrosion and surface effects. A computerized data base of LLW leaching data and mathematical models is being developed. The data is being used for model evaluation by curve fitting and statistical analysis according to standard procedures of statistical quality control. Long-term leach tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms. Initial results on the effect of temperature on leachability indicate that the leach rates of cement and VES waste forms increase with increasing temperature, whereas, the leach rate of bitumen is little affected. 10 refs., 5 figs.

  6. Neutron research and facility development at the Oak Ridge Electron Linear Accelerator 1970 to 1995

    SciTech Connect

    Peelle, R.W.; Harvey, J.A.; Maienschein, F.C.; Weston, L.W.; Olsen, D.K.; Larson, D.C.; Macklin, R.L.

    1982-07-01

    This report reviews the accomplishments of the first decade of operation of the Oak Ridge Electron Linear Accelerator (ORELA) and discusses the plans for the facility in the coming decade. Motivations for scientific and applied research during the next decade are included. In addition, ORELA is compared with competing facilities, and prospects for ORELA's improvement and even replacement are reported. Development efforts for the next few years are outlined that are consistent with the anticipated research goals. Recommendations for hardware development include improving the electron injection system to give much larger short-pulse currents on a reliable basis, constructing an Electron Beam Injector Laboratory to help make this improvement possible, continuing a study of possibly replacing the electron accelerator with a proton machine, and replacing or upgrading the facility's data-acquistion and immediate-analysis computer systems. Increased operating time and more involvement of nuclear theorists are recommended, and an effective staff size for optimum use of this unique facility is discussed. A bibliography of all ORELA-related publications is included.

  7. Textile composite fuselage structures development

    NASA Technical Reports Server (NTRS)

    Jackson, Anthony C.; Barrie, Ronald E.; Chu, Robert L.

    1993-01-01

    Phase 2 of the NASA ACT Contract (NAS1-18888), Advanced Composite Structural Concepts and Materials Technology for Transport Aircraft Structures, focuses on textile technology, with resin transfer molding or powder coated tows. The use of textiles has the potential for improving damage tolerance, reducing cost and saving weight. This program investigates resin transfer molding (RTM), as a maturing technology for high fiber volume primary structures and powder coated tows as an emerging technology with a high potential for significant cost savings and superior structural properties. Powder coated tow technology has promise for significantly improving the processibility of high temperature resins such as polyimides.

  8. Design, realization and test of C-band accelerating structures for the SPARC_LAB linac energy upgrade

    NASA Astrophysics Data System (ADS)

    Alesini, D.; Bellaveglia, M.; Biagini, M. E.; Boni, R.; Brönnimann, M.; Cardelli, F.; Chimenti, P.; Clementi, R.; Di Pirro, G.; Di Raddo, R.; Ferrario, M.; Ficcadenti, L.; Gallo, A.; Kalt, R.; Lollo, V.; Palumbo, L.; Piersanti, L.; Schilcher, T.

    2016-11-01

    The energy upgrade of the SPARC_LAB photo-injector at LNF-INFN (Frascati, Italy) has been originally conceived replacing one low gradient (13 MV/m) 3 m long SLAC type S-band traveling wave (TW) section with two 1.4 m long C-band accelerating sections. Due to the higher gradients reached by such structures, a higher energy beam can be obtained within the same accelerator footprint length. The use of C-band structures for electron acceleration has been adopted in a few FEL linacs in the world, among others, the Japanese Free Electron Laser at SPring-8 and the SwissFEL at Paul Scherrer Institute (PSI). The C-band sections are traveling wave, constant impedance structures with symmetric input and output axial couplers. Their design has been optimized for the operation with a SLED RF pulse compressor. In this paper we briefly review their design criteria and we focus on the construction, tuning, low and high-power RF tests. We also illustrate the design and realization of the dedicated low level RF system that has been done in collaboration with PSI in the framework of the EU TIARA project. Preliminary experimental results appear to confirm the operation of such structures with accelerating gradients larger than 35 MV/m.

  9. Effects of Prenatal Irradiation with an Accelerated Heavy-Ion Beam on Postnatal Development in Rats

    NASA Astrophysics Data System (ADS)

    Wang, B.; Murakami, M.; Eguchi-Kasai, K.; Nojima, K.; Shang, Y.; Tanaka, K.; Fujita, K.; Coffigny, H.; Hayata, I.

    Effects on postnatal neurophysiological development in offspring were studied following exposure of pregnant Wistar rats to accelerated neon-ion beams with a LET value of about 30 keV mu m at a dose range from 0 1 Gy to 2 0Gy on the 15th day of gestation The age at which four physiologic markers appeared and five reflexes were acquired was examined prior to weaning Gain in body weight was monitored until the offspring were 3 months old Male offspring were evaluated as young adults using two behavioral tests The effects of X-rays at 200 kVp measured for the same biological end points were studied for comparison Our previous study on carbon-ion beams with a LET value of about 13 keV mu m was also cited to elucidate a possible LET-related effect For most of the endpoints at early age significant alteration was even observed in offspring prenatally received 0 1 Gy of accelerated neon ions while neither X rays nor carbon-ions under the same dose resulted in such a significant alteration compared to that from the sham-irradiated dams All offspring whose mothers received 2 0 Gy died prior to weaning Offspring from dams irradiated with accelerated neon ions generally showed higher incidences of prenatal death and preweaning mortality markedly delayed accomplishment in their physiological markers and reflexes and gain in body weight compared to those exposed to X-rays or carbon ions at doses of 0 1 to 1 5 Gy Significantly reduced ratios of main organ weight to body weight at postnatal ages of 30 60 and 90 days were also observed

  10. High Voltage Hall Accelerator Propulsion System Development for NASA Science Missions

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Shastry, Rohit; Pinero, Luis; Peterson, Todd; Dankanich, John; Mathers, Alex

    2013-01-01

    NASA Science Mission Directorates In-Space Propulsion Technology Program is sponsoring the development of a 3.8 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn Research Center and Aerojet are developing a high fidelity high voltage Hall accelerator (HiVHAc) thruster that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the HiVHAc engineering development unit thruster have been performed. In addition, the HiVHAc project is also pursuing the development of a power processing unit (PPU) and xenon feed system (XFS) for integration with the HiVHAc engineering development unit thruster. Colorado Power Electronics and NASA Glenn Research Center have tested a brassboard PPU for more than 1,500 hours in a vacuum environment, and a new brassboard and engineering model PPU units are under development. VACCO Industries developed a xenon flow control module which has undergone qualification testing and will be integrated with the HiVHAc thruster extended duration tests. Finally, recent mission studies have shown that the HiVHAc propulsion system has sufficient performance for four Discovery- and two New Frontiers-class NASA design reference missions.

  11. STRUCTURAL DESIGN CRITERIA FOR TARGET/BLANKET SYSTEM COMPONENT MATERIALS FOR THE ACCELERATOR PRODUCTION OF TRITIUM PROJECT

    SciTech Connect

    W. JOHNSON; R. RYDER; P. RITTENHOUSE

    2001-01-01

    The design of target/blanket system components for the Accelerator Production of Tritium (APT) plant is dependent on the development of materials properties data specified by the designer. These data are needed to verify that component designs are adequate. The adequacy of the data will be related to safety, performance, and economic considerations, and to other requirements that may be deemed necessary by customers and regulatory bodies. The data required may already be in existence, as in the open technical literature, or may need to be generated, as is often the case for the design of new systems operating under relatively unique conditions. The designers' starting point for design data needs is generally some form of design criteria used in conjunction with a specified set of loading conditions and associated performance requirements. Most criteria are aimed at verifying the structural adequacy of the component, and often take the form of national or international standards such as the ASME Boiler and Pressure Vessel Code (ASME B and PV Code) or the French Nuclear Structural Requirements (RCC-MR). Whether or not there are specific design data needs associated with the use of these design criteria will largely depend on the uniqueness of the conditions of operation of the component. A component designed in accordance with the ASME B and PV Code, where no unusual environmental conditions exist, will utilize well-documented, statistically-evaluated developed in conjunction with the Code, and will not be likely to have any design data needs. On the other hand, a component to be designed to operate under unique APT conditions, is likely to have significant design data needs. Such a component is also likely to require special design criteria for verification of its structural adequacy, specifically accounting for changes in materials properties which may occur during exposure in the service environment. In such a situation it is common for the design criteria and

  12. Accelerating Development of EV Batteries Through Computer-Aided Engineering (Presentation)

    SciTech Connect

    Pesaran, A.; Kim, G. H.; Smith, K.; Santhanagopalan, S.

    2012-12-01

    The Department of Energy's Vehicle Technology Program has launched the Computer-Aided Engineering for Automotive Batteries (CAEBAT) project to work with national labs, industry and software venders to develop sophisticated software. As coordinator, NREL has teamed with a number of companies to help improve and accelerate battery design and production. This presentation provides an overview of CAEBAT, including its predictive computer simulation of Li-ion batteries known as the Multi-Scale Multi-Dimensional (MSMD) model framework. MSMD's modular, flexible architecture connects the physics of battery charge/discharge processes, thermal control, safety and reliability in a computationally efficient manner. This allows independent development of submodels at the cell and pack levels.

  13. Preparative Scale Resolution of Enantiomers Enables Accelerated Drug Discovery and Development.

    PubMed

    Leek, Hanna; Andersson, Shalini

    2017-01-18

    The provision of pure enantiomers is of increasing importance not only for the pharmaceutical industry but also for agro-chemistry and biotechnology. In drug discovery and development, the enantiomers of a chiral drug depict unique chemical and pharmacological behaviors in a chiral environment, such as the human body, in which the stereochemistry of the chiral drugs determines their pharmacokinetic, pharmacodynamic and toxicological properties. We present a number of challenging case studies of up-to-kilogram separations of racemic or enriched isomer mixtures using preparative liquid chromatography and super critical fluid chromatography to generate individual enantiomers that have enabled the development of new candidate drugs within AstraZeneca. The combination of chromatography and racemization as well as strategies on when to apply preparative chiral chromatography of enantiomers in a multi-step synthesis of a drug compound can further facilitate accelerated drug discovery and the early clinical evaluation of the drug candidates.

  14. Design development of the SCDTL structure for the TOP linac

    NASA Astrophysics Data System (ADS)

    Picardi, L.; Ronsivalle, C.; Spataro, B.

    1999-04-01

    The Side Coupled Drift Tube Linac (SCDTL) is an attractive 3 GHz accelerating structure composed of short DTL tanks coupled together by side coupling cavities, in the course of development of the 200 MeV proton linear accelerator for proton therapy planned for the Terapia Oncologica con Protoni (TOP) program of the Italian National Institute of Health (Istituto Superiore di Sanità, ISS). The TOP Linac will be used to boost to 70 MeV the 7 MeV proton beam from a linac injector. Our main concern is to investigate in detail the characteristics of the structure in terms of RF properties of the accelerating mode, like longitudinal and transverse shunt impedance and quality factor, and of the other modes that cause the origin of the tank dispersion curve, in order to stabilize the behaviour under operating conditions. Calculations performed with the computer three-dimensional (3D) codes MAFIA and SOPRANO on the smallest unit of the system (a single DTL tank without coupling cavities) and experimental measurements made on a prototype have shown good agreement. Two possible supporting stem configurations (single stem and two stems 180° apart for each drift tube) were examined and a comparison of the results in both cases are discussed.

  15. Influence of solidification accelerators on structure formation of anhydrite-containing binders

    SciTech Connect

    Anikanova, L. Volkova, O. Kudyakov, A.; Sarkisov, Y.; Tolstov, D.

    2016-01-15

    The article presents results of scientific analysis of chemical additives influence on acid fluoride binder. It was found that the influence of sulfate nature additives on the process of hydration and solidification of the binder is similar to influence of additives on indissoluble anhydrite. Additives with SO{sub 4}{sup 2−} anion NO{sup −} are more efficient. The mentioned additives according to accelerating effect belong to the following succession: K{sub 2}SO{sub 4} > Na{sub 2}SO{sub 4} > FeSO{sub 4} > MgSO{sub 4}. Facilitation of the process of hydration and solidification of the binder, increase in density and durability of the binder (32 MPa) is to the greatest extent achieved with the introduction of 2% sodium sulfate additive of the binder’s mass into the composition of the binder along with the ultrasonic treatment of water solution. Directed crystal formation process with healing of porous structure by new growths presented as calcium sulfate dehydrate and hydroglauberite provides positive effect.

  16. GPU-accelerated model for fast, three-dimensional fluid-structure interaction computations.

    PubMed

    Nita, Cosmin; Itu, Lucian; Mihalef, Viorel; Sharma, Puneet; Rapaka, Saikiran

    2015-08-01

    In this paper we introduce a methodology for performing one-way Fluid-Structure interaction (FSI), i.e. where the motion of the wall boundaries is imposed. We use a Graphics Processing Unit (GPU) accelerated Lattice-Boltzmann Method (LBM) implementation and present an efficient workflow for embedding the moving geometry, given as a set of polygonal meshes, in the LBM computation. The proposed method is first validated in a synthetic experiment: a vessel which is periodically expanding and contracting. Next, the evaluation focuses on the 3D Peristaltic flow problem: a fluid flows inside a flexible tube, where a periodic wave-like deformation produces a fluid motion along the centerline of the tube. Different geometry configurations are used and results are compared against previously published solutions. The efficient approach leads to an average execution time of approx. one hour per computation, whereas 50% of it is required for the geometry update operations. Finally, we also analyse the effect of changing the Reynolds number on the flow streamlines: the flow regime is significantly affected by the Reynolds number.

  17. Structural Shielding Design of a 6 MV Flattening Filter Free Linear Accelerator: Indian Scenario

    PubMed Central

    Mishra, Bibekananda; Selvam, T. Palani; Sharma, P. K. Dash

    2017-01-01

    Detailed structural shielding of primary and secondary barriers for a 6 MV medical linear accelerator (LINAC) operated with flattening filter (FF) and flattening filter free (FFF) modes are calculated. The calculations have been carried out by two methods, one using the approach given in National Council on Radiation Protection (NCRP) Report No. 151 and the other based on the monitor units (MUs) delivered in clinical practice. Radiation survey of the installations was also carried out. NCRP approach suggests that the primary and secondary barrier thicknesses are higher by 24% and 26%. respectively, for a LINAC operated in FF mode to that of a LINAC operated in both FF and FFF modes with an assumption that only 20% of the workload is shared in FFF mode. Primary and secondary barrier thicknesses calculated from MUs delivered on clinical practice method also show the same trend and are higher by 20% and 19%, respectively, for a LINAC operated in FF mode to that of a LINAC operated in both FF and FFF modes. Overall, the barrier thickness for a LINAC operated in FF mode is higher about 20% to that of a LINAC operated in both FF and FFF modes.

  18. FACET ORIENTATION AND TROPISM: ASSOCIATION WITH ACCELERATED DEGENERATION OF STABILIZING STRUCTURES IN LOWER LUMBAR SPINE.

    PubMed

    Jelec, Vjekoslav; Turner, Rajka; Franić, Miljenko; Korušić, Anđelko; Rotim, Krešimir

    2016-03-01

    The influence of facet orientation and tropism on the process of spinal degeneration has been extensively studied during the last few decades, but there are still many controversies and conflicting results in this field of research. The biomechanical cause of accelerated degeneration of stabilizing structures in lower lumbar spine lies within the combination of several factors, but two most important ones are compressive load and more coronal facet orientation that offers less resistance against torsional loading. Axial rotation of lower lumbar spine is undoubtedly associated with higher strain in disc annulus, and enhanced range of secondary rotational movements may be even more significant for the progression of annular degeneration. Accordingly, more pronounced facet tropism could be having part in faster progression of disc degeneration in lower lumbar spine, as indicated by a number of recent studies. More sagittal facet orientation in patients with a higher facet osteoarthritis score at lower lumbar segments is very likely related to arthritic remodeling commonly seen in other synovial joints. There is also a possibility that it could be associated with the adaptation to partial loss of lumbar lordosis, as both coincide with advanced age.

  19. Development and construction of a neutron beam line for accelerator-based boron neutron capture synovectomy.

    PubMed

    Gierga, D P; Yanch, J C; Shefer, R E

    2000-01-01

    A potential application of the 10B(n, alpha)7Li nuclear reaction for the treatment of rheumatoid arthritis, termed Boron Neutron Capture Synovectomy (BNCS), is under investigation. In an arthritic joint, the synovial lining becomes inflamed and is a source of great pain and discomfort for the afflicted patient. The goal of BNCS is to ablate the synovium, thereby eliminating the symptoms of the arthritis. A BNCS treatment would consist of an intra-articular injection of boron followed by neutron irradiation of the joint. Monte Carlo radiation transport calculations have been used to develop an accelerator-based epithermal neutron beam line for BNCS treatments. The model includes a moderator/reflector assembly, neutron producing target, target cooling system, and arthritic joint phantom. Single and parallel opposed beam irradiations have been modeled for the human knee, human finger, and rabbit knee joints. Additional reflectors, placed to the side and back of the joint, have been added to the model and have been shown to improve treatment times and skin doses by about a factor of 2. Several neutron-producing charged particle reactions have been examined for BNCS, including the 9Be(p,n) reaction at proton energies of 4 and 3.7 MeV, the 9Be(d,n) reaction at deuteron energies of 1.5 and 2.6 MeV, and the 7Li(p,n) reaction at a proton energy of 2.5 MeV. For an accelerator beam current of 1 mA and synovial boron uptake of 1000 ppm, the time to deliver a therapy dose of 10,000 RBEcGy ranges from 3 to 48 min, depending on the treated joint and the neutron producing charged particle reaction. The whole-body effective dose that a human would incur during a knee treatment has been estimated to be 3.6 rem or 0.75 rem, for 1000 ppm or 19,000 ppm synovial boron uptake, respectively, although the shielding configuration has not yet been optimized. The Monte Carlo design process culminated in the construction, installation, and testing of a dedicated BNCS beam line on the high

  20. Development of a PYTHON-based emittance calculator at Fermilab Accelerator Science and Technology (FAST) facility

    NASA Astrophysics Data System (ADS)

    Green, A. T.

    Beam emittance is an important characteristic describing charged particle beams. In linear accelerators (linac), it is critical to characterize the beam phase space parameters and, in particular, to precisely measure transverse beam emittance. The quadrupole scan (quad-scan) is a well-established technique used to characterize transverse beam parameters in four-dimensional phase space, including beam emittance. A computational algorithm with PYTHON scripts has been developed to estimate beam parameters, in particular beam emittance, using the quad-scan technique in the electron linac at the Fermilab Accelerator Science and Technology (FAST) facility. This script has been implemented in conjunction with an automated quad-scan tool (also written in PYTHON) and has decreased the time it takes to perform a single quad-scan from an hour to a few minutes. From the experimental data, the emittance calculator quickly delivers several results including: geometrical and normalized transverse emittance, Courant-Snyder parameters, and plots of the beam size versus quadrupole field strength, among others. This paper will discuss the details of the techniques used, the results from several quad-scans preformed at FAST during the electron injector commissioning, and the PYTHON code used to obtain the results.

  1. Recent advances in the development of high average power induction accelerators for industrial and environmental applications

    SciTech Connect

    Neau, E.L.

    1994-09-01

    Short-pulse accelerator technology developed during the early 1960`s through the late 1980`s is being extended to high average power systems capable of use in industrial and environmental applications. Processes requiring high dose levels and/or high volume throughput will require systems with beam power levels from several hundreds of kilowatts to megawatts. Beam accelerating potentials can range from less than 1 MeV to as much as 10 MeV depending on the type of beam, depth of penetration required, and the density of the product being treated. This paper addresses the present status of a family of high average power systems, with output beam power levels up to 200 kW, now in operation that use saturable core switches to achieve output pulse widths of 50 to 80 nanoseconds. Inductive adders and field emission cathodes are used to generate beams of electrons or x-rays at up to 2.5 MeV over areas of 1000 cm{sup 2}. Similar high average power technology is being used at {le} 1 MeV to drive repetitive ion beam sources for treatment of material surfaces over 100`s of cm{sup 2}.

  2. Development of Velocity Guidance Assistance System by Haptic Accelerator Pedal Reaction Force Control

    NASA Astrophysics Data System (ADS)

    Yin, Feilong; Hayashi, Ryuzo; Raksincharoensak, Pongsathorn; Nagai, Masao

    This research proposes a haptic velocity guidance assistance system for realizing eco-driving as well as enhancing traffic capacity by cooperating with ITS (Intelligent Transportation Systems). The proposed guidance system generates the desired accelerator pedal (abbreviated as pedal) stroke with respect to the desired velocity obtained from ITS considering vehicle dynamics, and provides the desired pedal stroke to the driver via a haptic pedal whose reaction force is controllable and guides the driver in order to trace the desired velocity in real time. The main purpose of this paper is to discuss the feasibility of the haptic velocity guidance. A haptic velocity guidance system for research is developed on the Driving Simulator of TUAT (DS), by attaching a low-inertia, low-friction motor to the pedal, which does not change the original characteristics of the original pedal when it is not operated, implementing an algorithm regarding the desired pedal stroke calculation and the reaction force controller. The haptic guidance maneuver is designed based on human pedal stepping experiments. A simple velocity profile with acceleration, deceleration and cruising is synthesized according to naturalistic driving for testing the proposed system. The experiment result of 9 drivers shows that the haptic guidance provides high accuracy and quick response in velocity tracking. These results prove that the haptic guidance is a promising velocity guidance method from the viewpoint of HMI (Human Machine Interface).

  3. New options for developing of nuclear energy using an accelerator-driven reactor

    SciTech Connect

    Takahashi, Hiroshi

    1997-09-01

    Fissile fuel can be produced at a high rate using an accelerator-driven Pu-fueled subcritical fast reactor. Thus, the necessity of early introduction of the fast reactor can be moderated. High reliability of the proton accelerator, which is essential to implementing an accelerator-driven reactor in the nuclear energy field can be achieved by a slight extension of the accelerator`s length, with only a small economical penalty. Subcritical operation provides flexible nuclear energy options including high neutron economy producing the fuel, transmuting high-level wastes, such as minor actinides, and of converting efficiently the excess Pu and military Pu into proliferation-resistant fuel.

  4. A Study of Higher-Band Dipole Wakefields in X-Band Accelerating Structures for the G/NLC

    SciTech Connect

    Jones, R

    2004-09-02

    The X-band linacs for the G/NLC (Global/Next Linear Collider) have evolved from the DDS (Damped Detuned Structure) series. The present accelerating structures are 60 cm in length and incorporate damping and detuning of the dipole modes which comprise the wakefield. In order to adequately damp the wakefield, frequencies of adjacent structures are interleaved. Limited analysis has been done previously on the higher order dipole bands. Here, we calculate the contribution of higher order bands of interleaved structures to the wakefield. Beam dynamics issues are also studied.

  5. Analytical Validation of Accelerator Mass Spectrometry for Pharmaceutical Development: the Measurement of Carbon-14 Isotope Ratio.

    SciTech Connect

    Keck, B D; Ognibene, T; Vogel, J S

    2010-02-05

    Accelerator mass spectrometry (AMS) is an isotope based measurement technology that utilizes carbon-14 labeled compounds in the pharmaceutical development process to measure compounds at very low concentrations, empowers microdosing as an investigational tool, and extends the utility of {sup 14}C labeled compounds to dramatically lower levels. It is a form of isotope ratio mass spectrometry that can provide either measurements of total compound equivalents or, when coupled to separation technology such as chromatography, quantitation of specific compounds. The properties of AMS as a measurement technique are investigated here, and the parameters of method validation are shown. AMS, independent of any separation technique to which it may be coupled, is shown to be accurate, linear, precise, and robust. As the sensitivity and universality of AMS is constantly being explored and expanded, this work underpins many areas of pharmaceutical development including drug metabolism as well as absorption, distribution and excretion of pharmaceutical compounds as a fundamental step in drug development. The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of {sup 14}C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the {sup 14}C label), stable across samples storage conditions for at least one year, linear over 4 orders of magnitude with an analytical range from one tenth Modern to at least 2000 Modern (instrument specific). Further, accuracy was excellent between 1 and 3 percent while precision expressed as coefficient of variation is between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of carbon-14 (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with {sup 14}C corresponds to 30 fg

  6. Residual acceleration data on IML-1: Development of a data reduction and dissemination plan

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. Iwan D.; Wolf, Randy

    1992-01-01

    The need to record some measure of the low-gravity environment of an orbiting space vehicle was recognized at an early stage of the U.S. Space Program. Such information was considered important for both the assessment of an astronaut's physical condition during and after space missions and the analysis of the fluid physics, materials processing, and biological sciences experiments run in space. Various measurement systems were developed and flown on space platforms beginning in the early 1970's. Similar in concept to land based seismometers that measure vibrations caused by earthquakes and explosions, accelerometers mounted on orbiting space vehicles measure vibrations in and of the vehicle due to internal and external sources, as well as vibrations in a sensor's relative acceleration with respect to the vehicle to which it is attached. The data collected over the years have helped to alter the perception of gravity on-board a space vehicle from the public's early concept of zero-gravity to the science community's evolution of thought from microgravity to milligravity to g-jitter or vibrational environment. Since the advent of the Shuttle Orbiter Program, especially since the start of Spacelab flights dedicated to scientific investigations, the interest in measuring the low-gravity environment in which experiments are run has increased. This interest led to the development and flight of numerous accelerometer systems dedicated to specific experiments. It also prompted the development of the NASA MSAD-sponsored Space Acceleration Measurement System (SAMS). The first SAMS units flew in the Spacelab on STS-40 in June 1991 in support of the first Spacelab Life Sciences mission (SLS-1). SAMS is currently manifested to fly on all future Spacelab missions.

  7. Residual acceleration data on IML-1: Development of a data reduction and dissemination plan

    NASA Astrophysics Data System (ADS)

    Rogers, Melissa J. B.; Alexander, J. Iwan D.; Wolf, Randy

    1992-09-01

    The need to record some measure of the low-gravity environment of an orbiting space vehicle was recognized at an early stage of the U.S. Space Program. Such information was considered important for both the assessment of an astronaut's physical condition during and after space missions and the analysis of the fluid physics, materials processing, and biological sciences experiments run in space. Various measurement systems were developed and flown on space platforms beginning in the early 1970's. Similar in concept to land based seismometers that measure vibrations caused by earthquakes and explosions, accelerometers mounted on orbiting space vehicles measure vibrations in and of the vehicle due to internal and external sources, as well as vibrations in a sensor's relative acceleration with respect to the vehicle to which it is attached. The data collected over the years have helped to alter the perception of gravity on-board a space vehicle from the public's early concept of zero-gravity to the science community's evolution of thought from microgravity to milligravity to g-jitter or vibrational environment. Since the advent of the Shuttle Orbiter Program, especially since the start of Spacelab flights dedicated to scientific investigations, the interest in measuring the low-gravity environment in which experiments are run has increased. This interest led to the development and flight of numerous accelerometer systems dedicated to specific experiments. It also prompted the development of the NASA MSAD-sponsored Space Acceleration Measurement System (SAMS). The first SAMS units flew in the Spacelab on STS-40 in June 1991 in support of the first Spacelab Life Sciences mission (SLS-1). SAMS is currently manifested to fly on all future Spacelab missions.

  8. Schooling in Times of Acceleration

    ERIC Educational Resources Information Center

    Buddeberg, Magdalena; Hornberg, Sabine

    2017-01-01

    Modern societies are characterised by forms of acceleration, which influence social processes. Sociologist Hartmut Rosa has systematised temporal structures by focusing on three categories of social acceleration: technical acceleration, acceleration of social change, and acceleration of the pace of life. All three processes of acceleration are…

  9. Narrow bandwidth Thomson photon source development using Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Geddes, C. G. R.; van Tilborg, J.; Tsai, H.-E.; Toth, Cs.; Vay, J.-L.; Lehe, R.; Schroeder, C. B.; Esarey, E.; Rykovanov, S. G.; Grote, D. P.; Friedman, A.; Leemans, W. P.

    2016-10-01

    Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs). An independent scattering laser with controlled pulse shaping in frequency and amplitude can be used together with laser guiding to realize high photon yield and narrow bandwidth. Simulations are presented on production of controllable narrow bandwidth sources using the beam and plasma capabilities of LPAs. Recent experiments and simulations demonstrate controllable LPAs in the energy range appropriate to MeV Thomson sources. Design of experiments and laser capabilities to combine these elements will be presented, towards a compact photon source system. A dedicated facility under construction will be described. Work supported by US DOE NNSA DNN R&D and by Sc. HEP under contract DE-AC02-05CH11231.

  10. An introduction to acceleration mechanisms

    SciTech Connect

    Palmer, R.B.

    1987-05-01

    This paper discusses the acceleration of charged particles by electromagnetic fields, i.e., by fields that are produced by the motion of other charged particles driven by some power source. The mechanisms that are discussed include: Ponderamotive Forces, Acceleration, Plasma Beat Wave Acceleration, Inverse Free Electron Laser Acceleration, Inverse Cerenkov Acceleration, Gravity Acceleration, 2D Linac Acceleration and Conventional Iris Loaded Linac Structure Acceleration. (LSP)

  11. SSME structural dynamic model development

    NASA Technical Reports Server (NTRS)

    Foley, M. J.; Tilley, D. M.; Welch, C. T.

    1983-01-01

    A mathematical model of the Space Shuttle Main Engine (SSME) as a complete assembly, with detailed emphasis on LOX and High Fuel Turbopumps is developed. The advantages of both complete engine dynamics, and high fidelity modeling are incorporated. Development of this model, some results, and projected applications are discussed.

  12. Self-accelerated development of salt karst during flash floods along the Dead Sea Coast, Israel

    NASA Astrophysics Data System (ADS)

    Avni, Yoav; Lensky, Nadav; Dente, Elad; Shviro, Maayan; Arav, Reuma; Gavrieli, Ittai; Yechieli, Yoseph; Abelson, Meir; Lutzky, Hallel; Filin, Sagi; Haviv, Itai; Baer, Gidon

    2016-01-01

    We document and analyze the rapid development of a real-time karst system within the subsurface salt layers of the Ze'elim Fan, Dead Sea, Israel by a multidisciplinary study that combines interferometric synthetic aperture radar and light detection and ranging measurements, sinkhole mapping, time-lapse camera monitoring, groundwater level measurements and chemical and isotopic analyses of surface runoff and groundwater. The >1 m/yr drop of Dead Sea water level and the subsequent change in the adjacent groundwater system since the 1960s resulted in flushing of the coastal aquifer by fresh groundwater, subsurface salt dissolution, gradual land subsidence and formation of sinkholes. Since 2010 this process accelerated dramatically as flash floods at the Ze'elim Fan were drained by newly formed sinkholes. During and immediately after these flood events the dissolution rates of the subsurface salt layer increased dramatically, the overlying ground surface subsided, a large number of sinkholes developed over short time periods (hours to days), and salt-saturated water resurged downstream. Groundwater flow velocities increased by more than 2 orders of magnitudes compared to previously measured velocities along the Dead Sea. The process is self-accelerating as salt dissolution enhances subsidence and sinkhole formation, which in turn increase the ponding areas of flood water and generate additional draining conduits to the subsurface. The rapid terrain response is predominantly due to the highly soluble salt. It is enhanced by the shallow depth of the salt layer, the low competence of the newly exposed unconsolidated overburden and the moderate topographic gradients of the Ze'elim Fan.

  13. Magnetized Plasma-filled Waveguide: A New High-Gradient Accelerating Structure

    SciTech Connect

    Avitzour, Yoav; Shvets, Gennady

    2009-01-22

    Electromagnetic waves confined between the metal plates of a plasma-filled waveguide are investigated. It is demonstrated that when the plasma is magnetized along the metallic plates, there exists a luminous accelerating wave propagating with a very slow group velocity. It is shown that the magnetized plasma 'isolates' the metal wall from the transverse electric field, thereby reducing potential breakdown problems. Applications of the metallic plasma-filled waveguide to particle accelerations and microwave pulse manipulation are described.

  14. Highly symmetric interfacial coherent structures in Rayleigh Taylor instability with time-dependent acceleration

    NASA Astrophysics Data System (ADS)

    Bhowmick, Aklant K.; Abarzhi, Snezhana

    2016-11-01

    Rayleigh Taylor instability in a power-law time dependent acceleration field is investigated theoretically for a flow with the symmetry group p6mm (hexagon) in the plane normal to acceleration. In the nonlinear regime, regular asymptotic solutions form a one-parameter family. The physically significant solution is identified with the one having the fastest growth and being stable (bubble tip velocity). Two distinct regimes are identified depending on the acceleration exponent. Particularly, the RM-type regime, where the dynamics is identical to conventional RM instability and is dominated by initial conditions, and the RT-type regime where the dynamics is dominated by the acceleration term. For the latter, the time dependence has profound effects on the dynamics. In the RT non-linear regime, the time dependence has no consequence on the morphology of the bubbles; the growth rate (bubble tip velocity) evolves as power law with the exponent set by the acceleration. The solutions for a one-parameter family, and are convergent with exponential decay of Fourier amplitudes. The solutions are stable at maximum tip velocity, whereas flat bubbles are unstable, and the growth/decay of perturbations is no longer purely exponential and depends on the acceleration exponent. The work is supported by the US National Science Foundation.

  15. Highly symmetric interfacial structures in Rayleigh Taylor instability with time-dependent acceleration

    NASA Astrophysics Data System (ADS)

    Bhowmick, Aklant K.; Abarzhi, Snezhana

    2016-10-01

    Rayleigh Taylor instability in a power-law time dependent acceleration field is investigated for a flow with the symmetry group p6mm (hexagonal) in the plane normal to acceleration. The Regular asymptotic solutions form a one-parameter family and the physically significant solution is identified with the one having the fastest growth and being stable (bubble tip velocity). Two distinct regimes are identified dependent on the acceleration exponent, the RM-type regime, where the dynamics is identical to conventional RM instability and is dominated by initial conditions, and the RT-type regime where the dynamics is dominated by the acceleration term. For the latter, the time dependence has profound effects on the dynamics. In the RT non-linear regime, the time dependence has no consequence on the morphology of the bubbles but the growth rate (bubble tip velocity) evolves as power law with the exponent set by the acceleration. The solutions for a one-parameter family, and are convergent with exponential decay of Fourier amplitudes close to the physical solution. The solutions are stable at maximum tip velocity and flat bubbles are unstable, and the growth/decay of perturbations is no longer purely exponential and depends on the acceleration exponent. The work is supported by the US National Science Foundation.

  16. Economic analysis of opportunities to accelerate Alzheimer’s disease research and development

    PubMed Central

    Scott, Troy J; O'Connor, Alan C; Link, Albert N; Beaulieu, Travis J

    2014-01-01

    The development of disease-modifying treatments for Alzheimer's disease (AD) faces a number of barriers. Among these are the lack of surrogate biomarkers, the exceptional size and duration of clinical trials, difficulties in identifying appropriate populations for clinical trials, and the limitations of monotherapies in addressing such a complex multifactorial disease. This study sets out to first estimate the consequent impact on the expected cost of developing disease-modifying treatments for AD and then to estimate the potential benefits of bringing together industry, academic, and government stakeholders to co-invest in, for example, developing better biomarkers and cognitive assessment tools, building out advanced registries and clinical trial-readiness cohorts, and establishing clinical trial platforms to investigate combinations of candidate drugs and biomarkers from the portfolios of multiple companies. Estimates based on interviews with experts on AD research and development suggest that the cost of one new drug is now $5.7 billion (95% confidence interval (CI) $3.7–9.5 billion) and could be reduced to $2.0 billion (95% CI $1.5–2.9 billion). The associated acceleration in the arrival of disease-modifying treatments could reduce the number of case years of dementia by 7.0 million (95% CI 4.4–9.4 million) in the United States from 2025 through 2040. PMID:24673372

  17. Microdosing, imaging biomarkers and SPECT: a multi-sided tripod to accelerate drug development.

    PubMed

    Pauwels, Ernest K J; Bergstrom, Kim; Mariani, Giuliano; Kairemo, Kalevi

    2009-01-01

    The advances of nuclear medicine imaging instrumentation and radiopharmaceutical sciences allow their involvement in the developmental processes of therapeutic drugs. New chemical entities, meant as potential drugs, need to comply with the proof-of-principle. Tomographic imaging methods as PET, SPECT and CT have been used for small animal and human studies at an early stage of drug development. Using a drug candidate in a radiolabeled form in obtaining quantitative imaging data provides opportunity for a complete morphological and functional overview of targeting properties and overall pharmacokinetics. This can be helpful in go/no-go decision making. Microdosing, using e.g.1% of the proposed dose of the radiolabeled potential drug plays an important part in this early development and notably reduces the risk of serious adverse effects in human volunteers or patients. This paper primarily focuses on the way in which microdosing and SPECT imaging may contribute to the development of drugs. Furthermore, this paper illustrates how these techniques may help to eliminate weak drug candidates at early stage, making time and funds available for potential lead compounds. Eventually this approach facilitates and accelerates new drug approval. The present paper highlights how these techniques make drug development easier in the field of oncology and neurology.

  18. An accelerated remedial strategy developed for J-Field, Aberdeen Proving Ground, Maryland

    SciTech Connect

    Yuen, C.R.; Martino, L.; Patton, T.; Wrobel, J.

    1995-06-01

    For an installation with many disposal sites and multiple contaminant sources, successful remediation at minimum cost can be complicated by insufficient geologic and hydrogeologic information, incomplete records of historical disposal activities, and uncertainty about the effectiveness of different investigative methods. To reduce these uncertainties and to increase the probability of successful remediation at minimum cost, a ``Phased and pilot`` accelerated remedial strategy has been developed for the J-Field area of Aberdeen Proving Ground, Maryland. The strategy includes four phases. First, the most contaminated site is selected as a pilot for detailed investigation. Second, the most contaminated areas within the pilot site are chosen as a pilot source area for interim action study, and a remedial action is developed to remove the primary contaminant sources. The subsequent sitewide investigation uses the effective tools developed in the first phase. Third, a cleanup operation is initiated in the pilot source area, while a sitewide feasibility study is developed by taking advantage of lessons learned in the interim action. Fourth, a sitewide cleanup operation proceeds.

  19. Economic analysis of opportunities to accelerate Alzheimer's disease research and development.

    PubMed

    Scott, Troy J; O'Connor, Alan C; Link, Albert N; Beaulieu, Travis J

    2014-04-01

    The development of disease-modifying treatments for Alzheimer's disease (AD) faces a number of barriers. Among these are the lack of surrogate biomarkers, the exceptional size and duration of clinical trials, difficulties in identifying appropriate populations for clinical trials, and the limitations of monotherapies in addressing such a complex multifactorial disease. This study sets out to first estimate the consequent impact on the expected cost of developing disease-modifying treatments for AD and then to estimate the potential benefits of bringing together industry, academic, and government stakeholders to co-invest in, for example, developing better biomarkers and cognitive assessment tools, building out advanced registries and clinical trial-readiness cohorts, and establishing clinical trial platforms to investigate combinations of candidate drugs and biomarkers from the portfolios of multiple companies. Estimates based on interviews with experts on AD research and development suggest that the cost of one new drug is now $5.7 billion (95% confidence interval (CI) $3.7-9.5 billion) and could be reduced to $2.0 billion (95% CI $1.5-2.9 billion). The associated acceleration in the arrival of disease-modifying treatments could reduce the number of case years of dementia by 7.0 million (95% CI 4.4-9.4 million) in the United States from 2025 through 2040.

  20. The solar wind structures associated with cosmic ray decreases and particle acceleration in 1978-1982

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Richardson, I. G.; Vonrosenvinge, T. T.

    1992-01-01

    The time histories of particles in the energy range 1 MeV to 1 GeV at times of all greater than 3 percent cosmic ray decreases in the years 1978 to 1982 are studied. Essentially all 59 of the decreases commenced at or before the passages of interplanetary shocks, the majority of which accelerated energetic particles. We use the intensity-time profiles of the energetic particles to separate the cosmic ray decreases into four classes which we subsequently associate with four types of solar wind structures. Decreases in class 1 (15 events) and class 2 (26 events) can be associated with shocks which are driven by energetic coronal mass ejections. For class 1 events the ejecta is detected at 1 AU whereas this is not the case for class 2 events. The shock must therefore play a dominant role in producing the depression of cosmic rays in class 2 events. In all class 1 and 2 events (which comprise 69 percent of the total) the departure time of the ejection from the sun (and hence the location) can be determined from the rapid onset of energetic particles several days before the shock passage at Earth. The class 1 events originate from within 50 deg of central meridian. Class 3 events (10 decreases) can be attributed to less energetic ejections which are directed towards the Earth. In these events the ejecta is more important than the shock in causing a depression in the cosmic ray intensity. The remaining events (14 percent of the total) can be attributed to corotating streams which have ejecta material embedded in them.

  1. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  2. 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

  3. Optimising translational oncology in clinical practice: strategies to accelerate progress in drug development.

    PubMed

    Stahel, R; Bogaerts, J; Ciardiello, F; de Ruysscher, D; Dubsky, P; Ducreux, M; Finn, S; Laurent-Puig, P; Peters, S; Piccart, M; Smit, E; Sotiriou, C; Tejpar, S; Van Cutsem, E; Tabernero, J

    2015-02-01

    Despite intense efforts, the socioeconomic burden of cancer remains unacceptably high and treatment advances for many common cancers have been limited, suggesting a need for a new approach to drug development. One issue central to this lack of progress is the heterogeneity and genetic complexity of many tumours. This results in considerable variability in therapeutic response and requires knowledge of the molecular profile of the tumour to guide appropriate treatment selection for individual patients. While recent advances in the molecular characterisation of different cancer types have the potential to transform cancer treatment through precision medicine, such an approach presents a major economic challenge for drug development, since novel targeted agents may only be suitable for a small cohort of patients. Identifying the patients who would benefit from individual therapies and recruiting sufficient numbers of patients with particular cancer subtypes into clinical trials is challenging, and will require collaborative efforts from research groups and industry in order to accelerate progress. A number of molecular screening platforms have already been initiated across Europe, and it is hoped that these networks, along with future collaborations, will benefit not only patients but also society through cost reductions as a result of more efficient use of resources. This review discusses how current developments in translational oncology may be applied in clinical practice in the future, assesses current programmes for the molecular characterisation of cancer and describes possible collaborative approaches designed to maximise the benefits of translational science for patients with cancer.

  4. Accelerating the development of improved analgesic treatments: the ACTION public-private partnership.

    PubMed

    Dworkin, Robert H; Turk, Dennis C

    2011-07-01

    There has been considerable progress identifying pathophysiologic mechanisms of neuropathic pain, but analgesic medications with improved efficacy, safety, and tolerability still represent an unmet public health need. Numerous treatments examined in recent randomized clinical trials (RCTs) have failed to show efficacy for neuropathic pain, including treatments that had previously demonstrated efficacy. This suggests that at least some negative results reflect limited assay sensitivity of RCTs to distinguish efficacious treatments from placebo. Patient characteristics, clinical trial research designs and methods, outcome measures, approaches to data analysis, and statistical power may all play a role in accounting for difficulties in demonstrating the benefits of efficacious analgesic treatments vs placebo. The identification of specific clinical trial characteristics associated with assay sensitivity in existing data has the potential to provide an evidence-based approach to the design of analgesic clinical trials. The US Food and Drug Administration recently launched the Analgesic Clinical Trial Innovations, Opportunities, and Networks (ACTION) public-private partnership, which is designed to facilitate the discovery and development of analgesics with improved efficacy, safety, and tolerability for acute and chronic pain conditions. ACTION will establish a collaborative effort to prioritize research objectives, develop a standardized analgesic database platform, and conduct methodologically focused studies to increase the assay sensitivity and efficiency of analgesic clinical trials. The results of these activities have the potential to inform and accelerate the development of improved pain management interventions of all types, not just pharmacologic treatments.

  5. Oil exports, structural change, and economic development in Iran

    SciTech Connect

    Emami-Khoi, A.

    1981-01-01

    Within the broad Chenery-Kuznets framework, using structural change as a major indicator of economic development, this study investigates the direction and magnitude and broad features of structural change in Iran, and the role of oil production and exports in that change. Although the study covers a larger horizon, the analysis is focused on the period 1955 through 1977. A similar but less-detailed investigation is conducted for Algeria, Indonesia, and Venezuela also, and a cross-country, comparative perspective is generated. The study shows that, in general, the structural changes in Iran have either been weak (for example, in production and employment), or they are contrary to what the model would predict (for instance in trade). The pattern of structural change observed in Iran, therefore, does not indicate any significant economic development even though per capita income increased five-fold over the period 1955 through 1977. In short, oil does not appear to have been an engine of economic development in Iran. The situation appears broadly similar for the other three countries. Based on these findings, the study offers some suggestions concerning the future economic strategies that should enhance very considerably the contribution that oil industry can make toward Iran's economic development, and should thus accelerate the pace of economic development. These suggestions may be useful to other oil-exporting countries as well.

  6. IMPEDANCE MEASUREMENT SETUP FOR HIGHER-ORDER MODE STUDIES IN NLC ACCELERATING STRUCTURES WITH THE WIRE METHOD

    SciTech Connect

    Baboi, Nicoleta

    2002-09-19

    Dipole modes are the main cause of transverse emittance dilution in the Japanese Linear Collider/Next Linear Collider (JLC/NLC). A diagnostic setup has been built in order to investigate them. The method is based on using a coaxial wire to excite and measure electromagnetic modes of accelerating structures. This method can offer a more efficient and less expensive procedure than the ASSET facility. Initial measurements have been made and are presented in this paper.

  7. Development and evaluation of polybenzoxazole fibrous structures

    NASA Technical Reports Server (NTRS)

    Orndoff, Evelyne

    1995-01-01

    Woven and braided polybenzoxazole (PBO) structures have been developed for aerospace applications. The properties of PBO fibers are compared to those of other high performance fibers. PBO is unique for combining excellent flammability properties with the highest tensile strength and modulus of all synthetic organic fibers. The PBO structures are specifically developed to be compared to similar Kevlar structures. The physical, mechanical, thermal, and oxidative properties of the PBO woven and braided structures are determined. The resistance to various chemicals and to UV light is evaluated. Recommendations for specific aerospace applications are given with comments for further development and industrial applications.

  8. Development of a subway operation incident delay model using accelerated failure time approaches.

    PubMed

    Weng, Jinxian; Zheng, Yang; Yan, Xuedong; Meng, Qiang

    2014-12-01

    This study aims to develop a subway operational incident delay model using the parametric accelerated time failure (AFT) approach. Six parametric AFT models including the log-logistic, lognormal and Weibull models, with fixed and random parameters are built based on the Hong Kong subway operation incident data from 2005 to 2012, respectively. In addition, the Weibull model with gamma heterogeneity is also considered to compare the model performance. The goodness-of-fit test results show that the log-logistic AFT model with random parameters is most suitable for estimating the subway incident delay. First, the results show that a longer subway operation incident delay is highly correlated with the following factors: power cable failure, signal cable failure, turnout communication disruption and crashes involving a casualty. Vehicle failure makes the least impact on the increment of subway operation incident delay. According to these results, several possible measures, such as the use of short-distance and wireless communication technology (e.g., Wifi and Zigbee) are suggested to shorten the delay caused by subway operation incidents. Finally, the temporal transferability test results show that the developed log-logistic AFT model with random parameters is stable over time.

  9. Accelerating the development of formal thinking in middle and high school students

    NASA Astrophysics Data System (ADS)

    Adey, Philip; Shayer, Michael

    In an attempt to accelerate the development of formal operations in average young adolescents, intervention lessons relating to all formal schemata were designed in the context of school science courses. Over a period of two years, up to 30 intervention lessons were given by science teachers to their classes in eight schools. Boys who started the program aged 12+ showed a pre-posttest effect size on Piagetian tests of 0.89 SD compared with control classes. In terms of British norms for the development of operational thinking this was a mean change from the 51st to the 74th percentile. Neither the middle school students nor the 12+ girls showed greater gain than the controls. Gains were shown by girls in one 11+ class and in the two 11+ laboratory classes. In the laboratory school students given intervention lessons by the researchers maintained their gains over controls in formal operations at a delayed posttest one year after cessation of the program. There was no effect on tests of science achievement during the intervention. It was argued that the interventions needed to be accompanied by in-service training designed to enable teachers to change their teaching style in line with their students' increased operational thinking capacity.

  10. Development of a new concept automatic frequency controller for an ultrasmall C-band linear accelerator guide.

    PubMed

    Kamino, Yuichiro; Tsukuda, Kazuhiro; Kokubo, Masaki; Miura, Sadao; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-08-01

    We are developing a four-dimensional, image-guided radiotherapy system with a gimbaled x-ray head. The system has pursuing irradiation capability in addition to precise irradiation capability, owing to its agile x-ray head. The moving x-ray head requires a very small C-band accelerator guide. The heat intensity of the accelerator guide is much higher than that of conventional S-band medical linear accelerators. The resonance frequency varies over almost 1.0 MHz with a thermal time constant of about 30 s. An automatic frequency controller (AFC) is employed to compensate for this variation in resonance frequency. Furthermore, we noted that fast AFC response is important for step-and-shoot intensity modulation radiotherapy (IMRT), in which the beam is turned on and off frequently. Therefore, we invented a digital AFC, based on a new concept, to provide effective compensation for the thermal characteristics of the accelerator guide and to ensure stable and optimized x-ray treatment. An important aspect of the performance of the AFC is the capture-frequency range over which the AFC can seek, lock on to, and track the resonance frequency. The conventional, analog AFC used in S-band medical linear accelerators would have a capture-frequency range of about 0.9 MHz, if applied to our accelerator guide, and would be inappropriate. Conversely, our new AFC has a capture-frequency range of 24 MHz, which is well suited to our accelerator guide. The design concept behind this new AFC has been developed and verified. A full prototype system was constructed and tested on an existing accelerator guide at the rated x-ray output (500 cGy/min) of our radiotherapy system, with a pulse-repetition frequency of 300 Hz. The AFC acquired the resonance frequency of the accelerator guide within 0.15 s after beam-on, and provided stable tracking and adjustment of the frequency of the microwave source to the resonance frequency of the accelerator guide. With a planned improvement of the

  11. Structural reliability methods: Code development status

    NASA Technical Reports Server (NTRS)

    Millwater, Harry R.; Thacker, Ben H.; Wu, Y.-T.; Cruse, T. A.

    1991-01-01

    The Probabilistic Structures Analysis Method (PSAM) program integrates state of the art probabilistic algorithms with structural analysis methods in order to quantify the behavior of Space Shuttle Main Engine structures subject to uncertain loadings, boundary conditions, material parameters, and geometric conditions. An advanced, efficient probabilistic structural analysis software program, NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) was developed as a deliverable. NESSUS contains a number of integrated software components to perform probabilistic analysis of complex structures. A nonlinear finite element module NESSUS/FEM is used to model the structure and obtain structural sensitivities. Some of the capabilities of NESSUS/FEM are shown. A Fast Probability Integration module NESSUS/FPI estimates the probability given the structural sensitivities. A driver module, PFEM, couples the FEM and FPI. NESSUS, version 5.0, addresses component reliability, resistance, and risk.

  12. Development of an Accelerated Test Design for Predicting the Service Life of the Solar Array at Mead, Nebraska

    NASA Technical Reports Server (NTRS)

    Gaines, G. B.; Thomas, R. E.; Noel, G. T.; Shilliday, T. S.; Wood, V. E.; Carmichael, D. C.

    1979-01-01

    An accelerated life test is described which was developed to predict the life of the 25 kW photovoltaic array installed near Mead, Nebraska. A quantitative model for accelerating testing using multiple environmental stresses was used to develop the test design. The model accounts for the effects of thermal stress by a relation of the Arrhenius form. This relation was then corrected for the effects of nonthermal environmental stresses, such as relative humidity, atmospheric pollutants, and ultraviolet radiation. The correction factors for the nonthermal stresses included temperature-dependent exponents to account for the effects of interactions between thermal and nonthermal stresses on the rate of degradation of power output. The test conditions, measurements, and data analyses for the accelerated tests are presented. Constant-temperature, cyclic-temperature, and UV types of tests are specified, incorporating selected levels of relative humidity and chemical contamination and an imposed forward-bias current and static electric field.

  13. Development and applications of a multi-purpose digital controller with a System-on-Chip FPGA for accelerators

    NASA Astrophysics Data System (ADS)

    Kurimoto, Yoshinori; Nakamura, Keigo

    2016-12-01

    J-PARC Main Ring (MR) is a high intensity proton synchrotron which accelerates protons from 3 GeV to 30 GeV. It has operated at a beam intensity of 390 kW and an upgrade toward the megawatt rating is scheduled. For higher beam intensity, some of the accelerator components require more intelligent and complicated functions. To consolidate such functions among various components, we developed multi-purpose digital boards using a System-on-Chip Field-Programmable Gated Array (SoC FPGA). In this paper, we describe the details of our developed boards as well as their possible applications. As an application of the boards, we have successfully performed the measurement of the betatron amplitude function during beam acceleration in J-PARC MR. The experimental setup and results of the measurement are also described in detail.

  14. 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.

  15. The MIT HEDP Accelerator Facility for education and advanced diagnostics development for OMEGA, Z and the NIF

    NASA Astrophysics Data System (ADS)

    Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Han, H. W.; Kabadi, N.; Lahmann, B.; Orozco, D.; Rojas Herrera, J.; Sio, H.; Sutcliffe, G.; Frenje, J.; Li, C. K.; Séguin, F. H.; Leeper, R.; Ruiz, C. L.; Sangster, T. C.

    2015-11-01

    The MIT HEDP Accelerator Facility utilizes a 135-keV linear electrostatic ion accelerator, a D-T neutron source and two x-ray sources for development and characterization of nuclear diagnostics for OMEGA, Z, and the NIF. The ion accelerator generates D-D and D-3He fusion products through acceleration of D ions onto a 3He-doped Erbium-Deuteride target. Fusion reaction rates around 106 s-1 are routinely achieved, and fluence and energy of the fusion products have been accurately characterized. The D-T neutron source generates up to 6 × 108 neutrons/s. The two x-ray generators produce spectra with peak energies of 35 keV and 225 keV and maximum dose rates of 0.5 Gy/min and 12 Gy/min, respectively. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) and Magnetic PTOF CVD-diamond-based bang time detectors. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  16. 805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D

    SciTech Connect

    S. Bricker; C. Compton; W. Hartung; M. Johnson; F. Marti; J. Popierlarski; R. C. York; et al

    2008-09-22

    A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 {center_dot} 10{sup 9} and 1.4 {center_dot} 10{sup 10} at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules. A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.

  17. Success Structure for Accelerated Acquisition of English by Young ESL Learners

    ERIC Educational Resources Information Center

    Mohamed, Abdul Rashid; Tumin, Mahani; Omar, Hamzah

    2008-01-01

    This is an investigation into the accelerated acquisition of English among young ESL learners in an International School. It employed an ethnographic case study approach where data were gathered through non-participant observations, unstructured interviews, relevant documents, students' portfolios, field notes and biographical details. The sample…

  18. DEVELOPMENT OF WATER JET PLASMA MIRROR FOR STAGING OF LASER PLASMA ACCELERATORS

    SciTech Connect

    Panasenko, Dmitriy; Gonsalves, Anthony J.; Leemans, Wim; Nakamura, Kei; Shu, Anthony; Toth, Csaba

    2009-05-04

    Staging Laser Plasma Accelerators (LPAs) is necessary in order to reach beam energies of 100 GeV and above. This requires incoupling of additional laser beams into accelerating stages. In order to maintain the high average accelerating gradient of a staged LPA, it is imperative to minimize the distance that is needed for laser incoupling. A plasma mirror is proposed as the final coupling optic reducing the coupling distance from tens of meters, using a conventional optic, to as small as a few cm. Both a planar water jet and a nitrocellulose foil are used as reflecting surfacesand characterized. A maximum reflectivity of 70percent was obtained using both surfaces.

  19. Losartan increases bone mass and accelerates chondrocyte hypertrophy in developing skeleton

    PubMed Central

    Rianon, Nahid; Rajagopal, Abbhirami; Munivez, Elda; Bertin, Terry; Dawson, Brian; Chen, Yuqing; Jiang, Ming-Ming; Lee, Brendan; Yang, Tao; Bae, Yangjin

    2015-01-01

    Angiotensin receptor blockers (ARBs) are a group of anti-hypertensive drugs that are widely used to treat pediatric hypertension. Recent application of ARBs to treat diseases such as Marfan syndrome or Alport syndrome has shown positive outcomes in animal and human studies, suggesting a broader therapeutic potential for this class of drugs. Multiple studies have reported a benefit of ARBs on adult bone homeostasis; however, its effect on the growing skeleton in children is unknown. We investigated the effect of Losartan, an ARB, in regulating bone mass and cartilage during development in mice. Wild type mice were treated with Losartan from birth until 6 weeks of age, after which bones were collected for microCT and histomorphometric analyses. Losartan increased trabecular bone volume vs. tissue volume (a 98% increase) and cortical thickness (a 9% increase) in 6-weeks old wild type mice. The bone changes were attributed to decreased osteoclastogenesis as demonstrated by reduced osteoclast number per bone surface in vivo and suppressed osteoclast differentiation in vitro. At the molecular level, Angiotensin II-induced ERK1/2 phosphorylation in RAW cells was attenuated by Losartan. Similarly, RANKL-induced ERK1/2 phosphorylation was suppressed by Losartan, suggesting a convergence of RANKL and angiotensin signaling at the level of ERK1/2 regulation. To assess the effect of Losartan on cartilage development, we examined the cartilage phenotype of wild type mice treated with Losartan in utero from conception to 1 day of age. Growth plates of these mice showed an elongated hypertrophic chondrocyte zone and increased Col10a1 expression level, with minimal changes in chondrocyte proliferation. Altogether, inhibition of the angiotensin pathway by Losartan increases bone mass and accelerates chondrocyte hypertrophy in growth plate during skeletal development. PMID:25779879

  20. Losartan increases bone mass and accelerates chondrocyte hypertrophy in developing skeleton.

    PubMed

    Chen, Shan; Grover, Monica; Sibai, Tarek; Black, Jennifer; Rianon, Nahid; Rajagopal, Abbhirami; Munivez, Elda; Bertin, Terry; Dawson, Brian; Chen, Yuqing; Jiang, Ming-Ming; Lee, Brendan; Yang, Tao; Bae, Yangjin

    2015-05-01

    Angiotensin receptor blockers (ARBs) are a group of anti-hypertensive drugs that are widely used to treat pediatric hypertension. Recent application of ARBs to treat diseases such as Marfan syndrome or Alport syndrome has shown positive outcomes in animal and human studies, suggesting a broader therapeutic potential for this class of drugs. Multiple studies have reported a benefit of ARBs on adult bone homeostasis; however, its effect on the growing skeleton in children is unknown. We investigated the effect of Losartan, an ARB, in regulating bone mass and cartilage during development in mice. Wild type mice were treated with Losartan from birth until 6 weeks of age, after which bones were collected for microCT and histomorphometric analyses. Losartan increased trabecular bone volume vs. tissue volume (a 98% increase) and cortical thickness (a 9% increase) in 6-weeks old wild type mice. The bone changes were attributed to decreased osteoclastogenesis as demonstrated by reduced osteoclast number per bone surface in vivo and suppressed osteoclast differentiation in vitro. At the molecular level, Angiotensin II-induced ERK1/2 phosphorylation in RAW cells was attenuated by Losartan. Similarly, RANKL-induced ERK1/2 phosphorylation was suppressed by Losartan, suggesting a convergence of RANKL and angiotensin signaling at the level of ERK1/2 regulation. To assess the effect of Losartan on cartilage development, we examined the cartilage phenotype of wild type mice treated with Losartan in utero from conception to 1 day of age. Growth plates of these mice showed an elongated hypertrophic chondrocyte zone and increased Col10a1 expression level, with minimal changes in chondrocyte proliferation. Altogether, inhibition of the angiotensin pathway by Losartan increases bone mass and accelerates chondrocyte hypertrophy in growth plate during skeletal development.

  1. Development of TiN Coating System for Long Beam Ducts of Accelerators

    NASA Astrophysics Data System (ADS)

    Shibata, Kyo; Hisamatsu, Hiromi; Kanazawa, Ken-Ichi; Suetsugu, Yusuke; Shirai, Mitsuru

    A Titanium Nitride (TiN) coating system for long beam ducts of accelerators was developed to reduce the secondary electron yield (SEY) from the inner surface and to mitigate the electron cloud effect. Coating was carried out by DC magnetron sputtering of pure titanium in argon (2.0 Pa) and nitrogen (0.5 Pa) atmospheres. A copper beam duct with a maximum length of 3.6 m was set vertically, and a titanium rod as a cathode was suspended from the top along the central axis of the duct. A movable solenoid coil with a length of 0.8 m externally supplied a magnetic field of 16 mT to accommodate the long duct. By moving the solenoid coil at specified time intervals, the TiN film was uniformly coated on the inner surface. The thickness of the coating was 200 nm, and the temperature of the ducts during the coating was 130°C. Several coated ducts were installed into the KEKB positron ring during the summer shutdown in 2007. In the subsequent beam operation, the reduction of electrons in the coated duct was confirmed.

  2. Anticancer properties of nimbolide and pharmacokinetic considerations to accelerate its development

    PubMed Central

    Wang, Lingzhi; Phan, Do Dang Khoa; Zhang, Jingwen; Ong, Pei-Shi; Thuya, Win Lwin; Soo, Ross; Wong, Andrea Li-Ann; Yong, Wei Peng; Lee, Soo Chin; Ho, Paul Chi-Lui; Sethi, Gautam; Goh, Boon Cher

    2016-01-01

    Nimbolide is one of the main components in the leaf extract of Azadirachta indica (A. indica). Accumulating evidence from various in vitro and in vivo studies indicates that nimbolide possesses potent anticancer activity against several types of cancer and also shows potential chemopreventive activity in animal models. The main mechanisms of action of nimbolide include anti-proliferation, induction of apoptosis, inhibition of metastasis and angiogenesis, and modulation of carcinogen-metabolizing enzymes. Although multiple pharmacodynamic (PD) studies have been carried out, nimbolide is still at the infant stage in the drug development pipeline due to the lack of systematic pharmacokinetic (PK) studies and long-term toxicological studies. Preclinical PK and toxicological studies are vital in determining the dosage range to support the safety of nimbolide for first-in-human clinical trials. In this review, we will provide a comprehensive summary for the current status of nimbolide as an anticancer and chemopreventive lead compound, and highlight the importance of systematic preclinical PK and toxicological studies in accelerating the process of application of nimbolide as a therapeutic agent against various malignancies. PMID:27027349

  3. New developments of 11C post-accelerated beams for hadron therapy and imaging

    NASA Astrophysics Data System (ADS)

    Augusto, R. S.; Mendonca, T. M.; Wenander, F.; Penescu, L.; Orecchia, R.; Parodi, K.; Ferrari, A.; Stora, T.

    2016-06-01

    Hadron therapy was first proposed in 1946 and is by now widespread throughout the world, as witnessed with the design and construction of the CNAO, HIT, PROSCAN and MedAustron treatment centres, among others. The clinical interest in hadron therapy lies in the fact that it delivers precision treatment of tumours, exploiting the characteristic shape (the Bragg peak) of the energy deposition in the tissues for charged hadrons. In particular, carbon ion therapy is found to be biologically more effective, with respect to protons, on certain types of tumours. Following an approach tested at NIRS in Japan [1], carbon ion therapy treatments based on 12C could be combined or fully replaced with 11C PET radioactive ions post-accelerated to the same energy. This approach allows providing a beam for treatment and, at the same time, to collect information on the 3D distributions of the implanted ions by PET imaging. The production of 11C ion beams can be performed using two methods. A first one is based on the production using compact PET cyclotrons with 10-20 MeV protons via 14N(p,α)11C reactions following an approach developed at the Lawrence Berkeley National Laboratory [2]. A second route exploits spallation reactions 19F(p,X)11C and 23Na(p,X)11C on a molten fluoride salt target using the ISOL (isotope separation on-line) technique [3]. This approach can be seriously envisaged at CERN-ISOLDE following recent progresses made on 11C+ production [4] and proven post-acceleration of pure 10C3/6+ beams in the REX-ISOLDE linac [5]. Part of the required components is operational in radioactive ion beam facilities or commercial medical PET cyclotrons. The driver could be a 70 MeV, 1.2 mA proton commercial cyclotron, which would lead to 8.1 × 10711C6+ per spill. This intensity is appropriate using 11C ions alone for both imaging and treatment. Here we report on the ongoing feasibility studies of such approach, using the Monte Carlo particle transport code FLUKA [6,7] to simulate

  4. Developments in accelerators and instrumentation relevant to imaging with charged particles and positron emitters

    SciTech Connect

    Alonso, J.R.

    1980-11-01

    In past years particle accelerators have become increasingly important tools for the advancement of medical science. From the pace of advancing technology and current directions in medical research, it is clear that this relationship between accelerators and medicine will only grow stronger in future years. In view of this importance, this relationship is investigated in some detail, with an eye not so much towards the medical uses of the beams produced, but more towards the technology associated with these accelerators and the criteria which make for successful incorporation of these machines into the clinical environment. In order to lay the necessary groundwork, the different kinds of accelerators found in medical use today are reviewed briefly discussing salient points of each.

  5. 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)

  6. Development of a second generation stereotactic apparatus for linear accelerator radiosurgery.

    PubMed

    Colombo, F; Casentini, L; Pozza, F; Chierego, G; Marchetti, C

    1991-01-01

    Linear accelerator radiosurgery technique is based on a multiple intersecting arc irradiations procedure. The coincidence of the axis of two rotation movements (of gantry and treatment couch) into the isocenter is critical for focusing irradiation. In October 1989, our linear accelerator was changed and the stereotactic apparatus had to be adapted to the new machine. After multiple mechanical tests of the new machine, the stereotactic head frame was fixed to the roller bearing allowing rotation of the couch. The new apparatus is described.

  7. Accelerator Development for the NRL (Naval Research Laboratory) Free Electron Laser Program

    DTIC Science & Technology

    1988-06-01

    34triple point" junction of the vacuum , ceramic insulator , and metal electrode. This leads to the flashover of the insulator , causing an arc which acts as...tungsten wire (25.4 um) into the transport vacuum system. The diode is housed in an Astron ceramic insulator stack. The voltage profile across the diode...accelerator vacuum wall. It is across these insulating breaks that the accelerating voltage is applied to the electron beam and any breakdown in these gaps

  8. Structural Change and Employment in Developing Countries.

    ERIC Educational Resources Information Center

    Kuzmin, S. A.

    1982-01-01

    Discusses factors contributing to structural changes in developing countries and concludes that unemployment and underemployment are best countered by generating new productive activities, developing economic linkages, and stimulating an increase in the number of workplaces. Advocates cooperation among developing nations. (JOW)

  9. School Site Staff Development: Structures and Processes.

    ERIC Educational Resources Information Center

    Solo, Leonard J.

    1985-01-01

    Analyzes the importance of staff development (broadly defined as anything that enables teachers to learn) and considers different development structures. Describes the role and duties of staff developer at a Cambridge, Massachusetts, elementary school as well as its "teacher teams," groups of instructors who meet monthly to discuss…

  10. Development and Use of Mark Sense Record Cards for Recording Medical Data on Pilots Subjected to Acceleration Stress

    NASA Technical Reports Server (NTRS)

    Smedal, Harald A.; Havill, C. Dewey

    1962-01-01

    A TIME-HONORED system of recording medical histories and the data obtained on physical and laboratory examination has been that of writing the information on record sheets that go into a folder for each patient. In order to have information which would be more readily retrieved, 'a program was initiated in 1952 by the U. S. Naval School of Aviation Medicine in connection with their "Care of the Flyer" study to place this information on machine record cards. In 1958, a machine record card method was developed for recording medical data in connection with the astronaut selection program. Machine record cards were also developed by the Aero Medical Laboratory, Wright-Patterson AFB, Ohio, and the Aviation Medical Acceleration Laboratory, Naval Air Development Center, Johnsville, Pennsylvania, for use in connection with a variety of tests including acceleration stress.1 Therefore, a variety of systems resulted in which data of a medical nature could easily be recalled. During the NASA, Ames Research Center centrifuge studies/'S the pilot subjects were interviewed after each centrifuge run, or series of runs, and subjective information was recorded in a log book by the usual history taking methods referred to above. After the methods Were reviewed, it' was recognized that a card system would be very useful in recording data from our pilots after they had been exposed to acceleration stress. Since the acceleration stress cards already developed did not meet our requirements, it was decided a different card was needed.

  11. Novel durable bio-photocatalyst purifiers, a non-heterogeneous mechanism: accelerated entrapped dye degradation into structural polysiloxane-shield nano-reactors.

    PubMed

    Dastjerdi, Roya; Montazer, Majid; Shahsavan, Shadi; Böttcher, Horst; Moghadam, M B; Sarsour, Jamal

    2013-01-01

    This research has designed innovative Ag/TiO(2) polysiloxane-shield nano-reactors on the PET fabric to develop novel durable bio-photocatalyst purifiers. To create these very fine nano-reactors, oppositely surface charged multiple size nanoparticles have been applied accompanied with a crosslinkable amino-functionalized polysiloxane (XPs) emulsion. Investigation of photocatalytic dye decolorization efficiency revealed a non-heterogeneous mechanism including an accelerated degradation of entrapped dye molecules into the structural polysiloxane-shield nano-reactors. In fact, dye molecules can be adsorbed by both Ag and XPs due to their electrostatic interactions and/or even via forming a complex with them especially with silver NPs. The absorbed dye and active oxygen species generated by TiO(2) were entrapped by polysiloxane shelter and the presence of silver nanoparticles further attract the negative oxygen species closer to the adsorbed dye molecules. In this way, the dye molecules are in close contact with concentrated active oxygen species into the created nano-reactors. This provides an accelerated degradation of dye molecules. This non-heterogeneous mechanism has been detected on the sample containing all of the three components. Increasing the concentration of Ag and XPs accelerated the second step beginning with an enhanced rate. Further, the treated samples also showed an excellent antibacterial activity.

  12. Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion

    SciTech Connect

    Kojima, A. Hanada, M.; Tobari, H.; Nishikiori, R.; Hiratsuka, J.; Kashiwagi, M.; Umeda, N.; Yoshida, M.; Ichikawa, M.; Watanabe, K.; Yamano, Y.; Grisham, L. R.

    2016-02-15

    Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

  13. Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion.

    PubMed

    Kojima, A; Hanada, M; Tobari, H; Nishikiori, R; Hiratsuka, J; Kashiwagi, M; Umeda, N; Yoshida, M; Ichikawa, M; Watanabe, K; Yamano, Y; Grisham, L R

    2016-02-01

    Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

  14. Ghrelin accelerates synapse formation and activity development in cultured cortical networks

    PubMed Central

    2014-01-01

    Background While ghrelin was initially related to appetite stimulation and growth hormone secretion, it also has a neuroprotective effect in neurodegenerative diseases and regulates cognitive function. The cellular basis of those processes is related to synaptic efficacy and plasticity. Previous studies have shown that ghrelin not only stimulates synapse formation in cultured cortical neurons and hippocampal slices, but also alters some of the electrophysiological properties of neurons in the hypothalamus, amygdala and other subcortical areas. However, direct evidence for ghrelin’s ability to modulate the activity in cortical neurons is not available yet. In this study, we investigated the effect of acylated ghrelin on the development of the activity level and activity patterns in cortical neurons, in relation to its effect on synaptogenesis. Additionally, we quantitatively evaluated the expression of the receptor for acylated ghrelin – growth hormone secretagogue receptor-1a (GHSR-1a) during development. Results We performed electrophysiology and immunohistochemistry on dissociated cortical cultures from neonates, treated chronically with acylated ghrelin. On average 76 ± 4.6% of the cortical neurons expressed GHSR-1a. Synapse density was found to be much higher in ghrelin treated cultures than in controls across all age groups (1, 2 or 3 weeks). In all cultures (control and ghrelin treated), network activity gradually increased until it reached a maximum after approximately 3 weeks, followed by a slight decrease towards a plateau. During early developmental stages (1–2 weeks), the activity was much higher in ghrelin treated cultures and consequently, they reached the plateau value almost a week earlier than controls. Conclusions Acylated ghrelin leads to earlier network formation and activation in cultured cortical neuronal networks, the latter being a possibly consequence of accelerated synaptogenesis. PMID:24742241

  15. a Development of Accelerated Life Test Method for Blower Motor for Automobile Using Inverse Power Law Model

    NASA Astrophysics Data System (ADS)

    Shin, Wae-Gyeong; Lee, Soo-Hong

    Reliability of automotive parts has been one of the most interesting fields in the automotive industry. Especially small DC motor was issued because of the increasing adoption for passengers' safety and convenience. This study was performed to develop the accelerated life test method using Inverse power law model for small DC motors. The failure mode of small DC motor includes brush wear-out. Inverse power law model is applied effectively the electronic components to reduce the testing time and to achieve the accelerating test conditions. Accelerated life testing method was induced to bring on the brush wear-out as increasing voltage of motor. Life distribution of the small DC motor was supposed to follow Weibull distribution and life test time was calculated under the conditions of B10 life and 90% confidence level.

  16. Electron Acceleration and Structure in the Quasi-perpendicular Collisionless Shock

    SciTech Connect

    Burgess, D.

    2005-08-01

    Electron acceleration at quasi-perpendicular shocks is a key problem in collisionless shock physics, in the context of the Earth's bow shock and other astrophysical situations. Fast Fermi acceleration, or reflection by adiabatic mirroring is a robust mechanism, but predicts that the highest energies are produced over a very small shock angle range, close to perpendicular where the reflected flux is decreasingly small. Pitch angle scattering has been shown to be effective in broadening the parameter range where this process is important. Using 2D hybrid simulations and electron test particle simulations, we show that ripples and oscillations of the shock surface are efficient scatters of suprathermal electrons. The results indicate that power law energy distributions can be obtained for both upstream and downstream energetic electrons, over a reasonably wide range of shock angles.

  17. Gas density structure of supersonic flows impinged on by thin blades for laser-plasma accelerators

    NASA Astrophysics Data System (ADS)

    Mao, H.-S.; Swanson, K. K.; Tsai, H.-E.; Barber, S. K.; Steinke, S.; van Tilborg, J.; Geddes, C. G. R.; Leemans, W. P.

    2017-03-01

    Density transition injection is an effective technique for controllably loading electrons into a trapped phase for laser-plasma accelerators. One common technique to achieve this fluid phenomenon is to impinge a thin blade on the plume of a supersonic nozzle. 2-D simulations show that the density transition accessible to a transverse laser is produced by a rapid re-expansion of the high pressure region behind the initial bow shock, and not by the bow shock produced by the blade, as is commonly thought. This pressure mismatched re-expansion generates compression waves that could coalesce into shock-fronts as they interact with the surrounding ambient gas. This has consequences when interpreting the electron injection mechanism. In the simulations presented here, the fluid dynamics of a supersonic nozzle impinged on by a thin, flat object is explored, along with the implications for electron beam injectors in laser-plasma accelerators.

  18. Time development of high-altitude auroral acceleration region plasma, potentials, and field-aligned current systems observed by Cluster during a substorm

    NASA Astrophysics Data System (ADS)

    Hull, A. J.; Chaston, C. C.; Fillingim, M. O.; Mozer, F.; Frey, H. U.

    2013-12-01

    The auroral acceleration region is an integral link in the chain of events that transpire during substorms, and the currents, plasma and electric fields undergo significant changes driven by complex dynamical processes deep in the magnetotail. These auroral acceleration processes in turn accelerate and heat the plasma that ultimately leads to some of the most intense global substorm auroral displays. The complex interplay between field-aligned current system formation, the development of parallel electric fields, and resultant changes in the plasma constituents that occur during substorms within or just above the auroral acceleration zone remain unclear. We present Cluster multi-point observations within the high-altitude acceleration region (> 3 Re altitude) at key instances during the development of a substorm. Of particular emphasis is on the time-development of the plasma, potentials and currents that occur therein with the aim of ascertaining high-altitude drivers of substorm active auroral acceleration processes and auroral emission consequences. Preliminary results show that the initial onset is dominated by Alfvenic activity as evidenced by the sudden occurrence of relatively intense, short-spatial scale Alfvenic currents and attendant energy dispersed, counterstreaming electrons poleward of the growth-phase arc. The Alfvenic currents are locally planar structures with characteristic thicknesses on the order of a few tens of kilometers. In subsequent passages by the other spacecraft, the plasma sheet region became hotter and thicker via the injection of new hot, dense plasma of magnetospheric origins poleward of the pre-existing growth phase arc. In association with the heating and/or thickening of the plasma sheet, the currents appeared to broaden to larger scales as Alfven dominated activity gave way to either inverted-V dominated or mixed inverted-V and Alfvenic behavior depending on location. The transition from Alfven dominated to inverted-V dominated

  19. Application of Rate Theory to Accelerated Durability Testing of Structural Adhesives

    DTIC Science & Technology

    1980-03-01

    comes too late to impact on material selection or design considerations. The analytical approach, coupled with an accelerated 10 testing program, is...estimated range and then evaluating the impact of each parameter on the failure rate and expected service life. The life-limiting components and the...interest of processing economy can be identified. This information can then be fed back into the system design process and the analyses repeated to

  20. The Effects of High Sustained Acceleration on the Acoustic Phonetic Structure of Speech. A Preliminary Investigation.

    DTIC Science & Technology

    1986-05-21

    displacement of the articulators. The effect is most clearly present for the second formant which is traditionally associated with tongue advancement. Diphthong...words produced at 1 G in both spectral and durational characteristics. The formant shifts observed were similar for both speakers. The first formant ...increased for the majority of vowels. The second formant tended to be lower for the front vowels /i, J/ and higher for the back vowel (u). Acceleration

  1. Development of a 15 T Nb3Sn accelerator dipole demonstrator at Fermilab

    SciTech Connect

    Novitski, I.; Andreev, N.; Barzi, E.; Carmichael, J.; Kashikhin, V. V.; Turrioni, D.; Yu, M.; Zlobin, A. V.

    2016-06-01

    Here, a 100 TeV scale Hadron Collider (HC) with a nominal operation field of at least 15 T is being considered for the post-LHC era, which requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are the key conditions for realization of such a machine. FNAL has started the development of a 15 T Nb3Sn dipole demonstrator for a 100 TeV scale HC. The magnet design is based on 4-layer shell type coils, graded between the inner and outer layers to maximize the performance and reduce the cost. The experience gained during the Nb3Sn magnet R&D is applied to different aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T Nb3Sn dipole and the steps towards the demonstration model fabrication.

  2. Strong current sheet at a magnetosheath jet: Kinetic structure and electron acceleration

    NASA Astrophysics Data System (ADS)

    Eriksson, E.; Vaivads, A.; Graham, D. B.; Khotyaintsev, Yu. V.; Yordanova, E.; Hietala, H.; André, M.; Avanov, L. A.; Dorelli, J. C.; Gershman, D. J.; Giles, B. L.; Lavraud, B.; Paterson, W. R.; Pollock, C. J.; Saito, Y.; Magnes, W.; Russell, C.; Torbert, R.; Ergun, R.; Lindqvist, P.-A.; Burch, J.

    2016-10-01

    Localized kinetic-scale regions of strong current are believed to play an important role in plasma thermalization and particle acceleration in turbulent plasmas. We present a detailed study of a strong localized current, 4900 nA m-2, located at a fast plasma jet observed in the magnetosheath downstream of a quasi-parallel shock. The thickness of the current region is ˜3 ion inertial lengths and forms at a boundary separating magnetosheath-like and solar wind-like plasmas. On ion scales the current region has the shape of a sheet with a significant average normal magnetic field component but shows strong variations on smaller scales. The dynamic pressure within the magnetosheath jet is over 3 times the solar wind dynamic pressure. We suggest that the current sheet is forming due to high velocity shears associated with the jet. Inside the current sheet we observe local electron acceleration, producing electron beams, along the magnetic field. However, there is no clear sign of ongoing reconnection. At higher energies, above the beam energy, we observe a loss cone consistent with part of the hot magnetosheath-like electrons escaping into the colder solar wind-like plasma. This suggests that the acceleration process within the current sheet is similar to the one that occurs at shocks, where electron beams and loss cones are also observed. Therefore, electron beams observed in the magnetosheath do not have to originate from the bow shock but can also be generated locally inside the magnetosheath.

  3. Optimization of radiation acceleration regime and the target structure in laser plasma interaction

    NASA Astrophysics Data System (ADS)

    Dudnikova, Galina; Lui, Chuan; Papadopoulos, Dennis; Sagdeev, Roald; Zigler, Ari

    2009-11-01

    Recent work [1,2] indicates that under proper conditions the interaction of ultra-short, high power lasers with thin foils can generate ion beams in the 100-200 MeV energy range with relatively low velocity dispersion. This technology can have major implications to medical ion proton cancer therapy since it can provide a relatively inexpensive table-top alternative to the current used traditional cyclotrons. This paper presents a simulation trade-off study of laser driven generation of quasi-monochromatic ion beams in the thin-foil Radiation Pressure Acceleration (RPA) regime. The radiation pressure accelerates the electron cloud, which in its turn transfers accelerates the ions due to the induced longitudinal charge separation fields. A series of two and three-dimensional PIC simulations are presented with emphasis on stabilizing the target plasma against Raleigh-Taylor and modulational instabilities. Such instabilities are known as the main obstacles in achieving monochromatic beams. [4pt] [1] B. Eliasson, C. Lui, et al. New Jour. Phys., 11, 2009.[0pt] [2] F. Pegoraro, S.V. Bulanov. Laser Phys., v19, N 2, 2009.

  4. Advances in Hot-Structure Development

    NASA Technical Reports Server (NTRS)

    Rivers, H. Kevin; Glass, David E.

    2006-01-01

    The National Aeronautics and Space Administration has actively participated in the development of hot structures technology for application to hypersonic flight systems. Hot structures have been developed for vehicles including the X-43A, X-37, and the Space Shuttle. These trans-atmospheric and atmospheric entry flight systems that incorporate hot-structures technology are lighter weight and require less maintenance than those that incorporate parasitic, thermal-protection materials that attach to warm or cool substructure. The development of hot structures requires a thorough understanding of material performance in an extreme environment, boundary conditions and load interactions, structural joint performance, and thermal and mechanical performance of integrated structural systems that operate at temperatures ranging from 1500 C to 3000 C, depending on the application. This paper will present recent advances in the development of hot structures, including development of environmentally durable, high temperature leading edges and control surfaces, integrated thermal protection systems, and repair technologies. The X-43A Mach-10 vehicle utilized carbon/carbon (C/C) leading edges on the nose, horizontal control surface, and vertical tail. The nose and vertical and horizontal tail leading edges were fabricated out of a 3:1 biased, high thermal conductivity C/C. The leading edges were coated with a three-layer coating comprised of a SiC conversion of the C/C, followed by a CVD layer of SiC, followed by a thin CVD layer of HfC. Work has also been performed on the development of an integrated structure and was focused on both hot and warm (insulated) structures and integrated fuselage/tank/TPS systems. The objective was to develop integrated multifunctional airframe structures that eliminate fragile external thermal-protection systems and incorporate the insulating function within the structure. The approach taken to achieve this goal was to develop candidate hypersonic

  5. Wake fields in 9-cell TESLA accelerating structures : Spectral Element Discontinuous Galerkin (SEDG) simulations.

    SciTech Connect

    Min, M.; Fischer, P. F.; Chae, Y.-C.

    2007-01-01

    Using our recently developed high-order accurate Maxwell solver, NEKCEM, we carried out longitudinal wakefield calculations for a 9-cell TESLA cavity structure in 3D. Indirect method is used for wake potential calculations. Computational results with NEKCEM are compared with those of GdfidL. NEKCEM uses a spectral element discontinuous Galerkin (SEDG) method based on a domain decomposition approach using spectral-element discretizations on Gauss-Lobatto-Legendre grids with body-conforming hexahedral meshes. The numerical scheme is designed to ensure high-order spectral accuracy, using the discontinuous Galerkin form with boundary conditions weakly enforced through a flux term between elements. Concerns related to implementation on wake potential calculations are discussed, and wake potential calculations with indirect method by NEKCEM compared with the results of the finite difference time-domain code GdfidL.

  6. GPU-accelerated computing for Lagrangian coherent structures of multi-body gravitational regimes

    NASA Astrophysics Data System (ADS)

    Lin, Mingpei; Xu, Ming; Fu, Xiaoyu

    2017-04-01

    Based on a well-established theoretical foundation, Lagrangian Coherent Structures (LCSs) have elicited widespread research on the intrinsic structures of dynamical systems in many fields, including the field of astrodynamics. Although the application of LCSs in dynamical problems seems straightforward theoretically, its associated computational cost is prohibitive. We propose a block decomposition algorithm developed on Compute Unified Device Architecture (CUDA) platform for the computation of the LCSs of multi-body gravitational regimes. In order to take advantage of GPU's outstanding computing properties, such as Shared Memory, Constant Memory, and Zero-Copy, the algorithm utilizes a block decomposition strategy to facilitate computation of finite-time Lyapunov exponent (FTLE) fields of arbitrary size and timespan. Simulation results demonstrate that this GPU-based algorithm can satisfy double-precision accuracy requirements and greatly decrease the time needed to calculate final results, increasing speed by approximately 13 times. Additionally, this algorithm can be generalized to various large-scale computing problems, such as particle filters, constellation design, and Monte-Carlo simulation.

  7. Germline mutation of Bap1 accelerates development of asbestos-induced malignant mesothelioma.

    PubMed

    Xu, Jinfei; Kadariya, Yuwaraj; Cheung, Mitchell; Pei, Jianming; Talarchek, Jacqueline; Sementino, Eleonora; Tan, Yinfei; Menges, Craig W; Cai, Kathy Q; Litwin, Samuel; Peng, Hongzhuang; Karar, Jayashree; Rauscher, Frank J; Testa, Joseph R

    2014-08-15

    Malignant mesotheliomas are highly aggressive tumors usually caused by exposure to asbestos. Germline-inactivating mutations of BAP1 predispose to mesothelioma and certain other cancers. However, why mesothelioma is the predominate malignancy in some BAP1 families and not others, and whether exposure to asbestos is required for development of mesothelioma in BAP1 mutation carriers are not known. To address these questions experimentally, we generated a Bap1(+/-) knockout mouse model to assess its susceptibility to mesothelioma upon chronic exposure to asbestos. Bap1(+/-) mice exhibited a significantly higher incidence of asbestos-induced mesothelioma than wild-type (WT) littermates (73% vs. 32%, respectively). Furthermore, mesotheliomas arose at an accelerated rate in Bap1(+/-) mice than in WT animals (median survival, 43 weeks vs. 55 weeks after initial exposure, respectively) and showed increased invasiveness and proliferation. No spontaneous mesotheliomas were seen in unexposed Bap1(+/-) mice followed for up to 87 weeks of age. Mesothelioma cells from Bap1(+/-) mice showed biallelic inactivation of Bap1, consistent with its proposed role as a recessive cancer susceptibility gene. Unlike in WT mice, mesotheliomas from Bap1(+/-) mice did not require homozygous loss of Cdkn2a. However, normal mesothelial cells and mesothelioma cells from Bap1(+/-) mice showed downregulation of Rb through a p16(Ink4a)-independent mechanism, suggesting that predisposition of Bap1(+/-) mice to mesothelioma may be facilitated, in part, by cooperation between Bap1 and Rb. Drawing parallels to human disease, these unbiased genetic findings indicate that BAP1 mutation carriers are predisposed to the tumorigenic effects of asbestos and suggest that high penetrance of mesothelioma requires such environmental exposure.

  8. 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.

  9. How can accelerated development of bioenergy contribute to the future UK energy mix? Insights from a MARKAL modelling exercise

    PubMed Central

    Clarke, Donna; Jablonski, Sophie; Moran, Brighid; Anandarajah, Gabrial; Taylor, Gail

    2009-01-01

    Background This work explores the potential contribution of bioenergy technologies to 60% and 80% carbon reductions in the UK energy system by 2050, by outlining the potential for accelerated technological development of bioenergy chains. The investigation was based on insights from MARKAL modelling, detailed literature reviews and expert consultations. Due to the number and complexity of bioenergy pathways and technologies in the model, three chains and two underpinning technologies were selected for detailed investigation: (1) lignocellulosic hydrolysis for the production of bioethanol, (2) gasification technologies for heat and power, (3) fast pyrolysis of biomass for bio-oil production, (4) biotechnological advances for second generation bioenergy crops, and (5) the development of agro-machinery for growing and harvesting bioenergy crops. Detailed literature searches and expert consultations (looking inter alia at research and development needs and economic projections) led to the development of an 'accelerated' dataset of modelling parameters for each of the selected bioenergy pathways, which were included in five different scenario runs with UK-MARKAL (MED). The results of the 'accelerated runs' were compared with a low-carbon (LC-Core) scenario, which assesses the cheapest way to decarbonise the energy sector. Results Bioenergy was deployed in larger quantities in the bioenergy accelerated technological development scenario compared with the LC-Core scenario. In the electricity sector, solid biomass was highly utilised for energy crop gasification, displacing some deployment of wind power, and nuclear and marine to a lesser extent. Solid biomass was also deployed for heat in the residential sector from 2040 in much higher quantities in the bioenergy accelerated technological development scenario compared with LC-Core. Although lignocellulosic ethanol increased, overall ethanol decreased in the transport sector in the bioenergy accelerated technological

  10. Research and Development of Wires and Cables for High-Field Accelerator Magnets

    SciTech Connect

    Barzi, Emanuela; Zlobin, Alexander V.

    2016-04-01

    The latest strategic plans for High Energy Physics endorse steadfast superconducting magnet technology R&D for future Energy Frontier Facilities. This includes 10 to 16 T Nb3Sn accelerator magnets for the luminosity upgrades of the Large Hadron Collider and eventually for a future 100 TeV scale proton-proton (pp) collider. This paper describes the multi-decade R&D investment in the Nb3Sn superconductor technology, which was crucial to produce the first reproducible 10 to 12 T accelerator-quality dipoles and quadrupoles, as well as their scale-up. We also indicate prospective research areas in superconducting Nb3Sn wires and cables to achieve the next goals for superconducting accelerator magnets. Emphasis is on increasing performance and decreasing costs while pushing the Nb3Sn technology to its limits for future pp colliders.

  11. Development of an RF Conditioning System for Charged-Particle Accelerators

    SciTech Connect

    Kang, Yoon W; Howlader, Mostofa; Shajedul Hasan, Dr. S. M.

    2008-01-01

    Charged-particle accelerators use various vacuum windows on their accelerating radio-frequency (RF) cavities to throughput very high RF power. Before being placed on the cavities, the windows should be cleaned, baked, and fully RF conditioned to prevent a poor vacuum from outgassing, as well as other forms of contamination. An example is the coaxial fundamental power coupler (FPC) with an annular alumina ceramic window for each of the 81 superconducting RF cavities in the Spallation Neutron Source (SNS) linear accelerator. The FPCs needed to be tested up to 650-kW peak in a traveling wave and 2.6 MW with standing wave peaks in 1.3 and 60 pulses/s at 805 MHz. In this paper, an Experimental-Physics-and-Industrial-Control-System-based RF conditioning system for the SNS RF test facility is presented. This paper summarizes the hardware and software design strategies, provides the results obtained, and describes the future research scope.

  12. Development of a 10 MW, 91 GHz Gyroklystron for W-Band Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Nielson, Jeff; Ives, Lawrence; Lawson, Wes; Arjona, Melany

    1999-11-01

    An international effort is underway to design advanced linear electron-positron colliders with mass energies beyond 1 TeV. High power RF sources are required to drive accelerators operating at frequencies as high as W-Band. Calabazas Creek Research, Inc. is funded by the U.S. Department of Energy to design a 10 MW, second harmonic, gyroklystron at 91 GHz. The program is coordinated with W-Band accelerator research at the Stanford Linear Accelerator Center. The goal is to achieve an electronic efficiency of 45presentation will describe the proposed electron gun, three cavity RF circuit, magnetic circuit, and input and output couplers. Current simulation results will be presented and design tradeoffs will be discussed.

  13. Scenarios for acceleration in fish development and the role of metamorphosis

    NASA Astrophysics Data System (ADS)

    Kooijman, S. A. L. M.; Pecquerie, L.; Augustine, S.; Jusup, M.

    2011-11-01

    We compare various alternative explanations of why embryo development is sometimes slow relative to juvenile and adult development on the basis of the standard Dynamic Energy Budget (DEB) model and make the comparison with avian altricial versus precocial development. We discuss the role of the energy investment ratio, which combines four different aspects of DEBs: allocation, assimilation, mobilisation and costs for structure. We show how this ratio affects the morphology of growth curves: the ratio of the slopes at start and birth during embryonic growth, as well as the von Bertalanffy time as function of ultimate length during post-embryonic growth. We propose an extension of the standard DEB model that combines a Gompertz (i.e. exponential) start with a von Bertalanffy 'tail' with a smooth transition; a combination that has been applied frequently in fisheries research and here given a mechanistic significance. Implications are that a slow embryonic development is combined with a fast post-metamorphic one and that parameters at metamorphosis depend on feeding history prior to metamorphosis. Identical individuals, in terms of parameter values and amounts of reserve and structure, will become permanently different when they experience different (local) environments, even if they experience identical environments after metamorphosis. This might explain part of the parameter variation amongst individuals.

  14. Signature of recent ice flow acceleration in the radar attenuation and temperature structure of Thwaites Glacier, West Antarctica

    NASA Astrophysics Data System (ADS)

    Schroeder, Dustin; Seroussi, Helene; Chu, Winnie; Young, Duncan

    2016-04-01

    Englacial temperature structure exerts significant control on the rheology and flow of glaciers and ice sheets. It is however logistically prohibitive to directly measure at the glacier-catchment scale. As a result, numerical ice sheet models often make broad assumptions about englacial temperatures based on contemporary ice surface velocities. However, this assumption might break down in regions - like the Amundsen Sea Embayment - that have experienced recent acceleration since temperature and rheology do not respond instantaneously to changes in ice flow regime. To address this challenge, we present a new technique for estimating englacial attenuation rates using bed echoes from radar sounding data. We apply this technique to an airborne survey of Thwaites Glacier and compare the results to temperature and attenuation structures modeled using the numerical Ice Sheet System Model (ISSM) for three surface velocity scenarios. These include contemporary surface velocities, surface velocities from the early 1970s, and ice-sheet balance velocities. We find that the observed attenuation structure is much closer to those modeled with pre-acceleration surface velocities. This suggests that ice sheet models initialized with contemporary surface velocities are likely overestimating the temperature and underestimating the rheology of the fast-flowing trunk and grounding zone of Thwaites Glacier.

  15. Production of Multi-Terawatt Time-Structured CO{sub 2} Laser Pulses for Ion Acceleration

    SciTech Connect

    Haberberger, Dan; Tochitsky, Sergei; Gong Chao; Joshi, Chan

    2010-11-04

    The UCLA Neptune Laboratory CO{sub 2} laser system has been recently upgraded to produce 3ps multi-terawatt 10{mu}m laser pulses. The laser energy is distributed over several 3 ps pulses separated by 18 ps. These temporally structured pulses are applied for laser driven ion acceleration in an H{sub 2} gas jet at a measured plasma density of 2x10{sup 19} cm{sup -3}. Protons in excess of 20 MeV have been observed in the forward direction and with energy spreads ({Delta}E/E{approx}10%).

  16. 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.

  17. Angiotensin II accelerates mammary gland development independently of high blood pressure in pregnancy-associated hypertensive mice.

    PubMed

    Murata, Kazuya; Baasanjav, Altansarnai; Kwon, Chulwon; Hashimoto, Misuzu; Ishida, Junji; Fukamizu, Akiyoshi

    2015-09-01

    Angiotensin II (AngII) is a vasopressor hormone that has critical roles in maintenance of normal blood pressure and pathogenesis of cardiovascular diseases. We previously generated pregnancy-associated hypertensive (PAH) mice by mating female human angiotensinogen transgenic mice with male human renin transgenic mice. PAH mice exhibit hypertension in late pregnancy by overproducing AngII. A recent study demonstrated that angiotensin II type I (AT1) receptor is expressed in mammary epithelial cells and its signaling is critical for mammary gland involution after weaning. However, the role of AngII-AT1 receptor signaling in the development of mammary gland during pregnancy remains unclear. In this study, to investigate the role of AngII-AT1 receptor signaling in mammary gland development during pregnancy, we analyzed the mammary gland of PAH mice. Histological and gene expression analyses revealed that lobuloalveolar development was accelerated with increased milk protein production and lipid accumulation in the mammary gland of PAH mice. Furthermore, AT1 receptor blocker treatment suppressed acceleration of mammary gland development in PAH mice, while the treatment of hydralazine, another antihypertensive drug, did not. These data suggest that AngII-AT1 receptor-induced signaling accelerates mammary gland development during pregnancy through hypertension-independent mechanism.

  18. Development of advanced modal methods for calculating transient thermal and structural response

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J.

    1991-01-01

    Higher-order modal methods for predicting thermal and structural response are evaluated. More accurate methods or ones which can significantly reduce the size of complex, transient thermal and structural problems are desirable for analysis and are required for synthesis of real structures subjected to thermal and mechanical loading. A unified method is presented for deriving successively higher-order modal solutions related to previously-developed, lower-order methods such as the mode displacement and mode-acceleration methods. A new method, called the force-derivative method, is used to obtain higher-order modal solutions for both uncoupled (proportionally-damped) structural problems as well as thermal problems and coupled (non-proportionally damped) structural problems. The new method is called the force-derivative method because, analogous to the mode-acceleration method, it produces a term that depends on the forcing function and additional terms that depend on the time derivatives of the forcing function.

  19. Polynomial chaos expansion in structural dynamics: Accelerating the convergence of the first two statistical moment sequences

    NASA Astrophysics Data System (ADS)

    Jacquelin, E.; Adhikari, S.; Sinou, J.-J.; Friswell, M. I.

    2015-11-01

    Polynomial chaos solution for the frequency response of linear non-proportionally damped dynamic systems has been considered. It has been observed that for lightly damped systems the convergence of the solution can be very poor in the vicinity of the deterministic resonance frequencies. To address this, Aitken's transformation and its generalizations are suggested. The proposed approach is successfully applied to the sequences defined by the first two moments of the responses, and this process significantly accelerates the polynomial chaos convergence. In particular, a 2-dof system with respectively 1 and 2 parameter uncertainties has been studied. The first two moments of the frequency response were calculated by Monte Carlo simulation, polynomial chaos expansion and Aitken's transformation of the polynomial chaos expansion. Whereas 200 polynomials are required to have a good agreement with Monte Carlo results around the deterministic eigenfrequencies, less than 50 polynomials transformed by the Aitken's method are enough. This latter result is improved if a generalization of Aitken's method (recursive Aitken's transformation, Shank's transformation) is applied. With the proposed convergence acceleration, polynomial chaos may be reconsidered as an efficient method to estimate the first two moments of a random dynamic response.

  20. Research and development for electropolishing of Nb for ILC accelerator cavities

    SciTech Connect

    Kelley, Michael J.

    2009-09-21

    The objectives of this project are to 1, Expand the scientific and technological understanding of the effect of post-treatment (electropolish, buffered chemical polish, low-temperature baking) on the surface of niobium; 2, Relate the knowledge to the performance of niobium superconducting radiofrequency accelerator cavities; and, 3, Thereby design and demonstrate an electropolish process that can be applied to complete cavities.