Science.gov

Sample records for accelerator structure development

  1. 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.

  2. 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.

  3. Development of Dielectric-Based High Gradient Accelerating Structures

    SciTech Connect

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

    2006-11-27

    High gradient accelerating structures using dielectric-lined circular waveguides have been developed for a number of years at Argonne National Laboratory. In this article, we first report the experimental results of high power rf testing on the quartz based Dielectric-Loaded Accelerating (DLA) structure carried out on Feb. 2006 at the Naval Research Laboratory. The motivation for this experiment is to test the multipactor effect on different materials under high power and high vacuum condition. Up to 12 MW pulsed rf went through the tube without breakdown. Multipactor appeared during the experiment but with different features compared to other materials like alumina. Photomultiplier Tube (PMT) measurements were introduced into the experiment for the first time to observe the light emission time and intensity. In the second part of this paper, ways to achieve higher gradient for DLA structures are proposed: 1) smaller ID and longitudinal gap free DLA structures to reduce multipactor and obtain higher gradient; 2) new coaxial type coupler to avoid dielectric gap and improve impedance matching; 3) double layered DLA structure to reduce rf loss and enhance shunt impedance as well.

  4. Prospects for Accelerated Development of High Performance Structural Materials

    SciTech Connect

    Zinkle, Steven J; Ghoniem, Nasr M.

    2011-01-01

    We present an overview of key aspects for development of steels for fission and fusion energy applications, by linking material fabrication to thermo-mechanical properties through a physical understanding of microstructure evolution. Numerous design constraints (e.g. reduced activation, low ductile-brittle transition temperature, low neutron-induced swelling, good creep resistance, and weldability) need to be considered, which in turn can be controlled through material composition and processing techniques. Recent progress in the development of high-performance steels for fossil and fusion energy systems is summarized, along with progress in multiscale modeling of mechanical behavior in metals. Prospects for future design of optimum structural steels in nuclear applications by utilization of the hierarchy of multiscale experimental and computational strategies are briefly described.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Twisted waveguide accelerating structure.

    SciTech Connect

    Kang, Y. W.

    2000-08-15

    A hollow waveguide with a uniform cross section may be used for accelerating charged particles if the phase velocity of an accelerating mode is equal to or less than the free space speed of light. Regular straight hollow waveguides have phase velocities of propagating electromagnetic waves greater than the free-space speed of light. if the waveguide is twisted, the phase velocities of the waveguide modes become slower. The twisted waveguide structure has been modeled and computer simulated in 3-D electromagnetic solvers to show the slow-wave properties for the accelerating mode.

  13. Development of an S-band accelerating structure with quasi-symmetric single-feed racetrack couplers

    NASA Astrophysics Data System (ADS)

    Heo, Hoon; Joo, Young-Do; Park, Yong-Jung; Kang, Heung-Sik; Lee, Heung-Soo; Oh, Kyoung-Min; Seo, Hyung-Seok; Noh, Sung-Ju

    2015-03-01

    We developed an S-band traveling-wave accelerating structure for the Pohang Accelerator Laboratory's X-ray free-electron laser (PAL-XFEL), and we fabricated and tested a full-scale prototype. In order to reduce the field asymmetry inside the coupler cavity, we used the SUPERFISH code and the CST MWS electromagnetic field solvers to design the constant-gradient traveling-wave accelerator to use quasi-symmetric single-feed racetrack couplers. The RF measurement results indicate that the accelerating gradient of the prototype structure is as high as 27 MV/m for an input RF power of 65 MW.

  14. Medium Beta Superconducting Accelerating Structures

    SciTech Connect

    Jean Delayen

    2001-09-01

    While, originally, the development of superconducting structures was cleanly divided between low-beta resonators for heavy ions and beta=1 resonators for electrons, recent interest in protons accelerators (high and low current, pulsed and cw) has necessitated the development of structures that bridge the gap between the two. These activities have resulted both in new geometries and in the adaptation of well-known geometries optimized to this intermediate velocity range. Their characteristics and properties are reviewed.

  15. EM Structure Based and Vacuum Acceleration

    SciTech Connect

    Colby, E.R.; /SLAC

    2005-09-27

    The importance of particle acceleration may be judged from the number of applications which require some sort of accelerated beam. In addition to accelerator-based high energy physics research, non-academic applications include medical imaging and treatment, structural biology by x-ray diffraction, pulse radiography, cargo inspection, material processing, food and medical instrument sterilization, and so on. Many of these applications are already well served by existing technologies and will profit only marginally from developments in accelerator technology. Other applications are poorly served, such as structural biology, which is conducted at synchrotron radiation facilities, and medical treatment using proton accelerators, the machines for which are rare because they are complex and costly. Developments in very compact, high brightness and high gradient accelerators will change how accelerators are used for such applications, and potentially enable new ones. Physical and technical issues governing structure-based and vacuum acceleration of charged particles are reviewed, with emphasis on practical aspects.

  16. MEQALAC rf accelerating structure

    SciTech Connect

    Keane, J.; Brodowski, J.

    1981-01-01

    A prototype MEQALAC capable of replacing the Cockcroft Walton pre-injector at BNL is being fabricated. Ten milliamperes of H/sup -/ beam supplied from a source sitting at a potential of -40 kilovolt is to be accelerated to 750 keV. This energy gain is provided by a 200 Megahertz accelerating system rather than the normal dc acceleration. Substantial size and cost reduction would be realized by such a system over conventional pre-accelerator systems.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. Advanced Microgravity Acceleration Measurement Systems Being Developed

    NASA Technical Reports Server (NTRS)

    Sicker, Ronald J.; Kacpura, Thomas J.

    2002-01-01

    The Advanced Microgravity Acceleration Measurement Systems (AMAMS) project at the NASA Glenn Research Center is part of the Instrument Technology Development program to develop advanced sensor systems. The primary focus of the AMAMS project is to develop microelectromechanical (MEMS) acceleration sensor systems to replace existing electromechanical-sensor-based systems presently used to assess relative gravity levels aboard spacecraft. These systems are used in characterizing both vehicle and payload responses to low-gravity vibroacoustic environments. The collection of microgravity acceleration data has cross-disciplinary utility to the microgravity life and physical sciences and the structural dynamics communities. The inherent advantages of semiconductor-based systems are reduced size, mass, and power consumption, while providing enhanced stability.

  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. 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.

  4. 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.

  5. High frequency single mode traveling wave structure for particle acceleration

    NASA Astrophysics Data System (ADS)

    Ivanyan, M. I.; Danielyan, V. A.; Grigoryan, B. A.; Grigoryan, A. H.; Tsakanian, A. V.; Tsakanov, V. M.; Vardanyan, A. S.; Zakaryan, S. V.

    2016-09-01

    The development of the new high frequency slow traveling wave structures is one of the promising directions in accomplishment of charged particles high acceleration gradient. The disc and dielectric loaded structures are the most known structures with slowly propagating modes. In this paper a large aperture high frequency metallic two-layer accelerating structure is studied. The electrodynamical properties of the slowly propagating TM01 mode in a metallic tube with internally coated low conductive thin layer are examined.

  6. Micromechanical structures and microelectronics for acceleration sensing

    SciTech Connect

    Davies, B.R.; Montague, S.; Smith, J.H.; Lemkin, M.

    1997-08-01

    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 microelectronis 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 {approx} 25 G accelerometer) will be discussed in the paper (where 1 G {approx} 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.

  7. 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.

  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. Development of Acceleration Sensor and Acceleration Evaluation System for Super-Low-Range Frequencies

    NASA Astrophysics Data System (ADS)

    Asano, Shogo; Matsumoto, Hideki

    2001-05-01

    This paper describes the development process for acceleration sensors used on automobiles and an acceleration evaluation system designed specifically for acceleration at super-low-range frequencies. The features of the newly developed sensor are as follows. 1) Original piezo-bimorph design based on a disc-center-fixed structure achieves pyroeffect cancelling and stabilization of sensor characteristics and enables the detection of the acceleration of 0.0009 G at the super-low-range-frequency of 0.03 Hz. 2) The addition of a self-diagnostic function utilizing the characteristics of piezoceramics enables constant monitoring of sensor failure. The frequency range of acceleration for accurate vehicle motion control is considered to be from DC to about 50 Hz. However, the measurement of acceleration in the super-low-range frequency near DC has been difficult because of mechanical and electrical noise interruption. This has delayed the development of the acceleration sensor for automotive use. We have succeeded in the development of an acceleration evaluation system for super-low-range frequencies from 0.015 Hz to 2 Hz with detection of the acceleration range from 0.0002 G (0.2 gal) to 1 G, as well as the development of a piezoelectric-type acceleration sensor for automotive use.

  10. 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.

  11. EM Structure-Based Accelerators Working Group Summary

    SciTech Connect

    Kimura, W.D.; Lidia, S.M.

    2004-12-07

    This Working Group (WG) focused on EM Structure-Based Accelerators, which covers a broad area of mechanisms and experiments. Topics covered included dielectric wakefield accelerators (DWA), photonic bandgap accelerators (PBGA), inverse free electron lasers (IFEL), vacuum laser accelerators (VLA), other novel schemes, and supporting analysis and modeling. In addition, this WG was tasked at the Workshop with developing conceptual (strawman) designs for a 1-GeV accelerator system based upon any of the experimentally-proven approaches covered in this WG. Two strawmen designs were developed based upon IFELs and DWAs. The presentations given and strawmen designs indicate great progress has been made in many areas. Proof-of-principle experiments will occur shortly in PBGA and VLA. Other well-proven devices, such as IFELs, are becoming accepted as 'workhorse' providers of microbunches.

  12. 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.

  13. 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. PMID:26260448

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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 retire,…

  19. 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.

  20. 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.

  1. Vehicle Systems Integration Laboratory Accelerates Powertrain Development

    SciTech Connect

    2014-04-15

    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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. Developing acceleration schedules for NDCX-II*

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    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.

  7. Accelerator development in India for ADS programme

    NASA Astrophysics Data System (ADS)

    Singh, P.; Rao, S. V. L. S.; Pande, Rajni; Basak, T.; Roy, Shweta; Aslam, M.; Jain, P.; Srivastava, S. C. L.; Kumar, Rajesh; Nema, P. K.; Kailas, S.; Sahni, V. C.

    2007-02-01

    At BARC, development of a Low Energy High Intensity Proton Accelerator (LEHIPA), as front-end injector of the 1 GeV accelerator for the ADS programme, has been initiated. The major components of LEHIPA (20 MeV, 30 mA) are a 50 keV ECR ion source, a 3 MeV Radio Frequency Quadrupole (RFQ) and a 20 MeV drift tube linac (DTL). The Low Energy Beam Transport (LEBT) and Medium Energy Beam Transport (MEBT) lines match the beam from the ion source to RFQ and from RFQ to DTL respectively. Design of these systems has been completed and fabrication of their prototypes has started. Physics studies of the 20-1000 MeV part of the Linac are also in progress. In this paper, the present status of this project is presented.

  8. Acceleration amplifications in nif structures subjected to earthquake base motions

    SciTech Connect

    McCallen, D

    1999-11-29

    NIF technical staff have questioned the possibility of obtaining acceleration amplifications (i.e. amplification of the ground acceleration values) in a structure which are significantly higher than the acceleration amplification exhibited across the period range in the input response spectrum. This note utilizes a simple example to illustrate that the acceleration amplification resulting from the dynamic response of a structural system can indeed be significantly higher than the amplifications indicated in the response spectrum, and that the GEMINI program is computing the appropriate acceleration levels for a simple MDOF system.

  9. 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…

  10. Development of an automatic frequency measurement system for RF linear accelerator magnetrons

    NASA Astrophysics Data System (ADS)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki; Lee, Seung Hyun; Park, Hyung Dal; Song, Ki Beak

    2015-06-01

    An X-band [9300 MHz] magnetron frequency measurement system was developed for the electron linear accelerators at the Korean Atomic Energy Research Institute (KAERI). The measurement and the display of the RF frequency during the accelerator operation time is a crucial factor for continuous operation for two key reasons. Firstly, if the RF frequency of the magnetron is not known, then the amount of frequency tuning cannot be known, and the appropriate RF power cannot be supplied to the accelerating-structure. Second, values including the accelerating-structure's coolingwater temperature setting, the solenoid-magnet's cooling-water temperature setting, and the tuning of the source's (magnetron's) frequency can be undertaken because the RF frequency is used as the reference. A key component of the accelerator is the accelerating-structure. The volume of the accelerating-structure changes according to the environment's temperature; there, the resonance frequency of the accelerating-structure varies. When the resonance frequency of the accelerator is changed, the output becomes unstable, and a low beam energy is obtained. Accordingly, was developed a magnetron frequency-measuring device in order to stabilize the accelerator's operation. The results of the test demonstrate that the measurement's accurate up to 100 kHz, which enables the provision of an accurate RF power to the accelerating -structure. In this paper, we discuss the RF frequency measurement system for the magnetron to enable a more stable accelerator operation in a linac.

  11. 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.

  12. 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.

  13. Developing acceleration schedules for NDCX-II

    SciTech Connect

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

    2008-08-11

    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 sub-millimeter radius and a duration of about 1 ns. An interactive 1-D particle-in-cell simulation with an electrostatic field solver, acceleation-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.

  14. 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.

  15. 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).

  16. Numerical studies of multipactor in dielectric-loaded accelerator structures

    NASA Astrophysics Data System (ADS)

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas

    2009-11-01

    Multipactor (MP) is known as the avalanche growth of the number of secondary electrons emitted from a solid surface exposed to an rf electric field under vacuum conditions. MP may occur in various microwave and rf systems such as microwave tubes, rf windows and launchers, accelerating structures, and rf satellite payloads. In this work we present results of MP analysis in dielectric-loaded accelerator (DLA) structures. The starting point of our work was experimental and theoretical studies of DLA structures jointly done by Argonne National Laboratory and Naval Research Laboratory (J. G. Power et al., Phys. Rev. Lett. 92, 164801 (2004); J. G. Power et al., AIP Conf. Proc. 877, 362 (2006)). In the theoretical model developed during those studies the space-charge field due to the total number of particles is taken into account as a parameter. We perform our studies using a self-consistent approach with the help of time-dependent two-dimensional code developed at the University of Maryland (O. V. Sinitsyn et al., Phys. Plasmas 16, 073102 (2009)). Results include analysis of MP evolution at an early stage, detailed studies of individual electron trajectories, analysis of MP onset time under various conditions and comparison of some results with the experimental data.

  17. ELECTROMAGNETIC SIMULATIONS OF LINEAR PROTON ACCELERATOR STRUCTURES USING DIELECTRIC WALL ACCELERATORS

    SciTech Connect

    Nelson, S; Poole, B; Caporaso, G

    2007-06-15

    Proton accelerator structures for medical applications using Dielectric Wall Accelerator (DWA) technology allow for the utilization of high electric field gradients on the order of 100 MV/m to accelerate the proton bunch. Medical applications involving cancer therapy treatment usually desire short bunch lengths on the order of hundreds of picoseconds in order to limit the extent of the energy deposited in the tumor site (in 3D space, time, and deposited proton charge). Electromagnetic simulations of the DWA structure, in combination with injections of proton bunches have been performed using 3D finite difference codes in combination with particle pushing codes. Electromagnetic simulations of DWA structures includes these effects and also include the details of the switch configuration and how that switch time affects the electric field pulse which accelerates the particle beam.

  18. 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.

  19. 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.

  20. Kif14 overexpression accelerates murine retinoblastoma development.

    PubMed

    O'Hare, Michael; Shadmand, Mehdi; Sulaiman, Rania S; Sishtla, Kamakshi; Sakisaka, Toshiaki; Corson, Timothy W

    2016-10-15

    The mitotic kinesin KIF14 has an essential role in the recruitment of proteins required for the final stages of cytokinesis. Genomic gain and/or overexpression of KIF14 has been documented in retinoblastoma and a number of other cancers, such as breast, lung and ovarian carcinomas, strongly suggesting its role as an oncogene. Despite evidence of oncogenic properties in vitro and in xenografts, Kif14's role in tumor progression has not previously been studied in a transgenic cancer model. Using a novel Kif14 overexpressing, simian virus 40 large T-antigen retinoblastoma (TAg-RB) double transgenic mouse model, we aimed to determine Kif14's role in promoting retinal tumor formation. Tumor initiation and development in double transgenics and control TAg-RB littermates were documented in vivo over a time course by optical coherence tomography, with subsequent ex vivo quantification of tumor burden. Kif14 overexpression led to an accelerated initiation of tumor formation in the TAg-RB model and a significantly decreased tumor doubling time (1.8 vs. 2.9 weeks). Moreover, overall percentage tumor burden was also increased by Kif14 overexpression. These data provide the first evidence that Kif14 can promote tumor formation in susceptible cells in vivo. PMID:27270502

  1. New linear accelerator (Linac) design based on C-band accelerating structures for SXFEL facility

    NASA Astrophysics Data System (ADS)

    Zhang, Meng; Gu, Qiang

    2011-11-01

    A C-band accelerator structure is one promising technique for a compact XFEL facility. It is also attractive in beam dynamics in maintaining a high quality electron beam, which is an important factor in the performance of a free electron laser. In this paper, a comparison between traditional S-band and C-band accelerating structures is made based on the linac configuration of a Shanghai Soft X-ray Free Electron Laser (SXFEL) facility. Throughout the comprehensive simulation, we conclude that the C-band structure is much more competitive.

  2. X-band dielectric loaded RF driven accelerator structures: Theoretical and experimental investigations

    NASA Astrophysics Data System (ADS)

    Zou, Peng

    An important area of application of high-power radio frequency (RF) and microwave sources is particle acceleration. A major challenge for the current worldwide research and development effort in linear accelerator is the search for a compact and affordable very-high-energy accelerator technology for the next generation supercolliders. It has been recognized for sometime that dielectric loaded accelerator structures are attractive candidates for the next generation very-high-energy linear accelerators, because they possess several distinct advantages over conventional metallic iris- loaded accelerator structures. However, some fundamental issues, such as RF breakdown in the dielectric, Joule heating, and vacuum properties of dielectric materials, are still the subjects of intense investigation, requiring the validation by experiments conducted at high power levels. An X-band traveling-wave accelerator based on dielectric-lined waveguide has been designed and constructed. Numerical calculation, bench measurements, and 3-D electromagnetic field simulation of this dielectric loaded accelerator are presented. One critical technical problem in constructing such dielectric loaded accelerator is efficient coupling of RF power into the dielectric-lined circular waveguide. A coupling scheme has been arrived at by empirical methods. Field distribution in this coupling configuration has been studied by numerical simulation. In the conventional iris-loaded accelerator structures, the peak surface electric field E s is in general found to be at least a factor of 2 higher than the axial acceleration field Ea. Because the peak surface electric field causes electric breakdown of the structure, it represents a direct limitation on the maximum acceleration gradient that can be obtained. A novel hybrid dielectric-iris-loaded periodic accelerator structure is proposed to utilize the advantages of both dielectric-lined waveguides and conventional iris-loaded structures. Numerical

  3. 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.

  4. Accelerated Application Development: The ORNL Titan Experience

    DOE PAGES

    Joubert, Wayne; Archibald, Richard K.; Berrill, Mark A.; Brown, W. Michael; Eisenbach, Markus; Grout, Ray; Larkin, Jeff; Levesque, John; Messer, Bronson; Norman, Matthew R.; et al

    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

  5. 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

  6. SLAB symmetric dielectric micron scale structures for high gradient electron acceleration.

    SciTech Connect

    Rosenzweig, J. B.; Schoessow, P. V.

    1999-06-12

    A class of planar microstructure is proposed which provide high accelerating gradients when excited by an infrared laser pulse. These structures consist of parallel dielectric slabs separated by a vacuum gap; the dielectric or the outer surface coating are spatially modulated at the laser wavelength along the beam direction so as to support a standing wave accelerating field. We have developed numerical and analytic models of the accelerating mode fields in the structure. We show an optimized coupling scheme such that this mode is excited resonantly with a large quality factor. The status of planned experiments on fabricating and measuring these planar structures will be described.

  7. Fabrication and Characterization of Woodpile Structures for Direct Laser Acceleration

    SciTech Connect

    McGuinness, C.; Colby, E.; England, R.J.; Ng, J.; Noble, R.J.; Peralta, E.; Soong, K.; Spencer, J.; Walz, D.; Byer, R.L.; /Stanford U., Ginzton Lab.

    2010-08-26

    An eight and nine layer three dimensional photonic crystal with a defect designed specifically for accelerator applications has been fabricated. The structures were fabricated using a combination of nanofabrication techniques, including low pressure chemical vapor deposition, optical lithography, and chemical mechanical polishing. Limits imposed by the optical lithography set the minimum feature size to 400 nm, corresponding to a structure with a bandgap centered at 4.26 {micro}m. Reflection spectroscopy reveal a peak in reflectivity about the predicted region, and good agreement with simulation is shown. The eight and nine layer structures will be aligned and bonded together to form the complete seventeen layer woodpile accelerator structure.

  8. 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.

  9. 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.

  10. Neuro-fuzzy control of structures using acceleration feedback

    NASA Astrophysics Data System (ADS)

    Schurter, Kyle C.; Roschke, Paul N.

    2001-08-01

    This paper described a new approach for the reduction of environmentally induced vibration in constructed facilities by way of a neuro-fuzzy technique. The new control technique is presented and tested in a numerical study that involves two types of building models. The energy of each building is dissipated through magnetorheological (MR) dampers whose damping properties are continuously updated by a fuzzy controller. This semi-active control scheme relies on the development of a correlation between the accelerations of the building (controller input) and the voltage applied to the MR damper (controller output). This correlation forms the basis for the development of an intelligent neuro-fuzzy control strategy. To establish a context for assessing the effectiveness of the semi-active control scheme, responses to earthquake excitation are compared with passive strategies that have similar authority for control. According to numerical simulation, MR dampers are less effective control mechanisms than passive dampers with respect to a single degree of freedom (DOF) building model. On the other hand, MR dampers are predicted to be superior when used with multiple DOF structures for reduction of lateral acceleration.

  11. 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.

  12. 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.

  13. 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

  14. Optimization of quasiperiodic structures in a linear resonance ion accelerator

    NASA Astrophysics Data System (ADS)

    Garashchenko, F. G.; Sokolov, L. S.; Tsulaya, A. V.

    1980-06-01

    A method is proposed for optimizing the parameters of a linear ion accelerator with rectangular or trapezoidal shape of the accelerating voltage between the tubes, systematic allowance being made for the quasiperiodicity of their arrangement. Numerical calculations have demonstrated the effectiveness of the method and also the fairly simple structure of its realization. A detailed algorithm is given. An estimate is made of the interval of entrance phases, the maximal value of which exceeds by several percent the limits previously predicted.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Development of a 20 MeV Dielectric-Loaded Accelerator Test Facility

    SciTech Connect

    Gold, Steven H.; Fliflet, Arne W.; Kinkead, Allen K.; Gai Wei; Power, John G.; Konecny, Richard; Jing Chunguang; Tantawi, Sami G.; Nantista, Christopher D.; Hu, Y.; Chen, H.; Tang, C.; Lin, Y.; Bruce, Ralph W.; Bruce, Robert L.; Lewis, David III

    2004-12-07

    This paper describes 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 accelerator (DLA) test facility powered by a high-power 11.424-GHz magnicon amplifier. The magnicon can presently produce 25 MW of output power in a 250-ns pulse at 10 Hz, and efforts are in progress to increase this to 50 MW. The facility will include a 5 MeV electron injector being developed by the Accelerator Laboratory of Tsinghua University in Beijing, China. The DLA test structures are being developed by ANL, and some have undergone testing at NRL at gradients up to {approx}8 MV/m. SLAC is developing a means to combine the two magnicon output arms, and to drive an injector and accelerator with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRL, is developing a means to join short ceramic sections into a continuous accelerator tube by ceramic brazing using an intense millimeter-wave beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year. The facility will be used for testing DLA structures using a variety of materials and configurations, and also for testing other X-band accelerator concepts. The initial goal is to produce a compact 20 MeV dielectric-loaded test accelerator.

  2. Development of a 20-MeV Dielectric-Loaded Accelerator Test Facility

    SciTech Connect

    Gold, S.H.; Kinkead, A.K.; Gai, W.; Power, J.G.; Konecny, R.; Jing, C.G.; Tantawi, S.G.; Nantista, C.D.; Hu, Y.; Chen, H.; Tang, C.; Lin, Y.; Bruce, R.W.; Bruce, R.L.; Fliflet, A.W.; Lewis, D.; /Naval Research Lab, Wash., D.C. /LET Corp., Washington /Argonne /SLAC /Tsinghua U., Beijing

    2005-06-22

    This paper describes 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 accelerator (DLA) test facility powered by a high-power 11.424-GHz magnicon amplifier. The magnicon can presently produce 25 MW of output power in a 250-ns pulse at 10 Hz, and efforts are in progress to increase this to 50 MW. The facility will include a 5 MeV electron inector being developed by the Accelerator Laboratory of Tsinghua University in Beijing, China. The DLA test structures are being developed by ANL, and some have undergone testing at NRL at gradients up to {approx} 8 MV/m. SLAC is developing a means to combine the two magnicon output arms, and to drive an injector and accelerator with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRl, is developing a means to join short ceramic sections into a continuous accelerator tube by ceramic brazing using an intense millimeter-wave beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year. The facility will be used for testing DLA structures using a variety of materials and configurations, and also for testing other X-band accelerator concepts. The initial goal is to produce a compact 20 MeV dielectric-loaded test accelerator.

  3. 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.

  4. 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.

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

    SciTech Connect

    Gold, Steven H.; Fliflet, Arne W.; Lombardi, Marcie; Kinkead, Allen K.; Gai, Wei; Power, John G.; Konecny, Richard; Long, Jidong; Jing, Chunguang; Tantawi, Sami G.; Nantista, Christopher D.; Bruce, Ralph W.; Lewis, David III

    2006-11-27

    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.

  6. H-mode accelerating structures with PMQ focusing for low-beta ion beams

    SciTech Connect

    Kurennoy, Sergey S; O' Hara, James F; Olivas, Eric R; Rybarcyk, Lawrence J

    2010-01-01

    We are developing high-efficiency normal-conducting RF accelerating structures based on inter-digital H-mode (IH) cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. Such IH-PMQ accelerating structures following a short RFQ can be used in the front end of ion linacs or in stand-alone applications, e.g. a compact deuteron-beam accelerator up to the energy of several MeV. Results of combined 3-D modeling for a full IH-PMQ accelerator tank - electromagnetic computations, beam-dynamics simulations with high currents, and thermal-stress analysis - are presented. The accelerating field profile in the tank is tuned to provide the best beam propagation using coupled iterations of electromagnetic and beam-dynamics modeling. A cold model of the IH-PMQ tank is being manufactured.

  7. 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.

  8. Grating-based deflecting, focusing, and diagnostic dielectric laser accelerator structures

    SciTech Connect

    Soong, Ken; Byer, R. L.; Colby, E. R.; England, R. J.; Peralta, E. A.

    2012-12-21

    Recent technological advances has made possible the realization of the first laser-driven particle accelerator structure to be fabricated lithographically. However, a complete particle accelerator requires more than just accelerating elements. In this paper, we present a grating-based design for three other quintessential accelerator elements: the focusing structure, the deflecting structure, and the diagnostic structure.

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  12. 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.

  13. Progress toward externally powered x-band dielectric-loaded accelerating structures.

    SciTech Connect

    Gai, W.; Power, J. G.; Liu, W.; Jing, C.; Gold, S. H.; Kinead, A. K.; Tantawi, S. G.; Dolgashev, V.; Kanareykin, A.; Konecny, R.; Wanming, L.

    2010-06-01

    We summarize recent progress in a program to develop externally powered dielectric-loaded accelerating (DLA) structures that can sustain high accelerating gradients. High-power RF tests of earlier structures showed strong multipactor loading. In addition, arcing at dielectric joints between the uniform DLA structure and matching sections at either end limited the achievable gradient. In this paper, we study the onset of multipactor in a DLA structure. We also study the effect of thin-film TiN coatings applied by atomic layer deposition and the effect of a reduction in the inner diameter of the structure. Test results of these structures show significant decreases in multipactor loading. We also test new structure designs that eliminate separate dielectric matching sections and, thus, the requirement for dielectric joints, including a DLA structure using a coaxial coupler and a clamped DLA structure. The clamped structure demonstrated a significantly improved gradient without breakdown.

  14. 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.

  15. 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.

  16. 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.

  17. Summary Report of Working Group 7: Electromagnetic-Structure Based Accelerators

    SciTech Connect

    Colby, E.; Musumeci, P.; /INFN, Rome

    2007-04-02

    We detail the most pressing physics and technical issues confronting short-wavelength acceleration. We review new acceleration concepts that are proposed and under development, and recent progress on technical issues such as structure fabrication and material damage. We outline key areas where work is still needed before a reliable assessment of the value of working at wavelengths below 1 cm can be made. Possible ways to enhance collaboration and progress in this important area are also discussed.

  18. 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.

  19. 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.

  20. Variable frequency heavy-ion linac, RILAC I. Design, construction and operation of its accelerating structure

    NASA Astrophysics Data System (ADS)

    Odera, Masatoshi; Chiba, Yoshiaki; Tonuma, Tadao; Hemmi, Masatake; Miyazawa, Yoshitoshi; Inoue, Toshihiko; Kambara, Tadashi; Kase, Masayuki; Kubo, Toshiyuki; Yoshida, Fusako

    1984-11-01

    A variable frequency linear accelerator at RIKEN (IPCR), which is named RILAC, is designed to accelerate ions of almost every element in the periodic table. In this report, the design, construction and performance of the resonator cavities of this linac are described. A new accelerating structure was developed for the variable frequency scheme. The principal aim of the development was to obtain a configuration within the cavity to keep a uniform voltage distribution along the accelerating axis over the wide range of resonant frequencies required. The final form adopted is a coaxial quarter-wave type resonator with a race-track-like cross section for its coaxial inner and outer conductors. It has a movable shorting device as a frequency tuner and its open end is enlarged and loaded with drift tubes, connected to the inner and outer conductors alternatingly. The structure can maintain the required uniformity of the accelerating voltage within 10% in spite of resonant frequency tuning between 17 and 45 MHz. A relatively modest accelerating gradient was chosen so that cw operation could be realized. The RILAC is composed of six such cavities which are independently excited and it succeeded in the acceleration of a beam through all the cavities in 1981.

  1. Comparison of the conditioning of high gradient accelerating structures

    NASA Astrophysics Data System (ADS)

    Degiovanni, Alberto; Wuensch, Walter; Giner Navarro, Jorge

    2016-03-01

    Accelerating gradients in excess of 100 MV /m , at very low breakdown rates, have been successfully achieved in numerous prototype CLIC accelerating structures. The conditioning and operational histories of several structures, tested at KEK and CERN, have been compared and there is clear evidence that the conditioning progresses with the number of rf pulses and not with the number of breakdowns. This observation opens the possibility that the optimum conditioning strategy, which minimizes the total number of breakdowns the structure is subject to without increasing conditioning time, may be to never exceed the breakdown rate target for operation. The result is also likely to have a strong impact on efforts to understand the physical mechanism underlying conditioning and may lead to preparation procedures which reduce conditioning time.

  2. 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.

  3. 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).

  4. 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.

  5. 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.

  6. 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.

  7. Status of the Development of the SINGAP Accelerator for ITER

    SciTech Connect

    Hemsworth, R. S.; Esch, H. P. L. de; Svensson, L.; Villecroze, F.

    2007-08-10

    The development of the Single Aperture, Single Gap 1 MV accelerator (SINGAP) is being carried out on the 1 MV test bed at the DRFC, CEA Cadarache, France. This paper reports on the latest performance achieved with the prototype, 'ITER-like' accelerator, 730 keV, 120 A/m2 D-, and of on-going measurements of the beam 'halo' fraction, {approx_equal}10%. It reviews the status and plans for future studies on D- production, and the observed 'dark current', and presents the basic physics design of a system that should cope with the {approx_equal}3 MW of electrons that would be co-accelerated out of the 1 MeV, 40 A, D- SINGAP accelerator proposed for the ITER neutral beam injectors.

  8. 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.

  9. 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

  10. Can hydromorphic conditions accelerate soil development?

    NASA Astrophysics Data System (ADS)

    Ringer, Marianna; Kiss, Klaudia; Horváth-Szabó, Kata; Réka Balázs, Brigitta; Németh, Tibor; Sipos, Péter; Szabó, Máté; Jakab, Gergely; Madarász, Balázs; Szalai, Zoltán

    2016-04-01

    The formation and development of waterlogged (hydromorphic) soils are primarily determined by long-term water saturation. The presence of water in the profile can result increasing speed of soil forming processes including the accumulation of organic matter or other components and mineralogical transformations. Original papers refer more than hundreds of years for this kinds of mineral transformations. We suppose that this process could be more rapid. This study focuses on the mineralogical investigation of a sandy meadow soil (calcic, gleyic Phaeozem ferric, arenic) located in a swampy area in Central Hungary. The starting time of the soil formation is a well documented fact: the parent material deposited during an extremely heavy flood event in the 1960s. Therefore, the studied soil profile is the result of the last half century. Our aim was to explore the degree of mineral phase alteration via soil formation during a half-century under hydromorphic conditions. Routine laboratory measurements (selective dissolution methods for the determination of amorphous and crystalline Fe, and Mn content, X-ray fluorescence spectroscopy measurements for elemental composition determination, X-ray powder diffraction for mineralogical composition, and particle sizing by laser diffraction) were implemented. Morphological and chemical study of carbonate and iron nodules was carried out by electron microprobe. Simple chemical tests (eg. Fe2+ indication by dipiridil test) and morphological observations were performed on the field. Redox potential (Eh) and pH were measured in 20 cm and 40 cm depths by field monitoring station during the vegetation period. Results show that well developed horizons have emerged during fifty years in the studied soil profile. The most intense mineralogical transformations developed in the zone of the heaviest redox oscillation. Soil formation under hydromorphic conditions proceeds at higher speeds contrariwise to the century time scale reported in

  11. Nb3Sn accelerator magnet development around the world

    SciTech Connect

    Michael J. Lamm

    2003-06-23

    During the past 30 years superconducting magnet systems have enabled accelerators to achieve energies and luminosities that would have been impractical if not impossible with resistive magnets. By far, NbTi has been the preferred conductor for this application because of its ductility and insensitivity of Jc to mechanical strain. This is despite the fact that Nb{sub 3}Sn has a more favorable Jc vs. B dependence and can operate at much higher temperatures. Unfortunately, NbTi conductor is reaching the limit of it usefulness for high field applications. Despite incremental increases in Jc and operation at superfluid temperatures, magnets are limited to approximately a 10 T field. Improvements in conductor performance combined with future requirements for accelerator magnets to have bore fields greater than 10 T or operate in areas of large beam-induced heat loads now make Nb{sub 3}Sn look attractive. Thus, laboratories in several countries are actively engaged in programs to develop Nb{sub 3}Sn accelerator magnets for future accelerator applications. A summary of this important research activity is presented along with a brief history of Nb{sub 3}Sn accelerator magnet development and a discussion of requirements for future accelerator magnets.

  12. 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.

  13. 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.

  14. 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…

  15. Separations technology development to support accelerator-driven transmutation concepts

    SciTech Connect

    Venneri, F.; Arthur, E.; Bowman, C.

    1996-10-01

    This is the final report of a one-year Laboratory-Directed Research and Development (LDRD) Project at the Los Alamos National Laboratory (LANL). This project investigated separations technology development needed for accelerator-driven transmutation technology (ADTT) concepts, particularly those associated with plutonium disposition (accelerator-based conversion, ABC) and high-level radioactive waste transmutation (accelerator transmutation of waste, ATW). Specific focus areas included separations needed for preparation of feeds to ABC and ATW systems, for example from spent reactor fuel sources, those required within an ABC/ATW system for material recycle and recovery of key long-lived radionuclides for further transmutation, and those required for reuse and cleanup of molten fluoride salts. The project also featured beginning experimental development in areas associated with a small molten-salt test loop and exploratory centrifugal separations systems.

  16. The coupled dipole modes of the NLC accelerator structure

    SciTech Connect

    Bane, K.L.F.; Gluckstern, R.; Holtkamp, N.

    1992-03-01

    The proposed accelerator cavity of the Next Linear Collider (NLC) is a disk-loaded structure composed of 200 cells, operating at 11.42 GHz. The proposed mode of operation is to accelerate bunches in trains of 10, with a bunch spacing of 42 cm. One problem is that one bunch in a train can excite transverse wakefields in the accelerator cavity which, in turn, can deflect following bunches and result in emittance growth. A method of curing this problem is to detune the transverse modes of the cavity. Beam dynamics simulations for the NLC have shown that by keeping the transverse wakefield at the positions of the nine trailing bunches at or below 1 MW/nC/m{sup 2} we can void emittance growth. Earlier, approximate calculations of the wakefields, which did not include the cell-to-cell coupling of the modes, have shown that by the proper Gaussian detuning the above level of cancellation can be achieved. A specific goal of this report is to see if this conclusion still holds when coupling is included in the calculation. Note that in this paper we focus on the modes belonging to the first dipole passband, which are the most important. A special feature of these modes in the detuned NLC cavity is that the cell-to-cell coupling changes sign somewhere in the middle of the structure.

  17. 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.

  18. H-mode accelerating structures with permanent-magnet quadrupole beam focusing

    NASA Astrophysics Data System (ADS)

    Kurennoy, S. S.; Rybarcyk, L. J.; O'Hara, J. F.; Olivas, E. R.; Wangler, T. P.

    2012-09-01

    We have developed high-efficiency normal-conducting rf accelerating structures by combining H-mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital H-mode (IH-PMQ) structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. Results of the combined 3D modeling—electromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysis—for an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar H-mode structures with PMQ focusing for higher beam velocities are also presented. H-PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.

  19. MYRRHA: A multipurpose accelerator driven system for research & development

    NASA Astrophysics Data System (ADS)

    Abderrahim, H. Aı̈t; Kupschus, P.; Malambu, E.; Benoit, Ph; Van Tichelen, K.; Arien, B.; Vermeersch, F.; D'hondt, P.; Jongen, Y.; Ternier, S.; Vandeplassche, D.

    2001-05-01

    SCK·CEN, the Belgian Nuclear Research Centre, in partnership with IBA s.a., Ion Beam Applications, is designing an ADS prototype, MYRRHA, and is conducting an associated R&D programme. The project focuses primarily on research on structural materials, nuclear fuel, liquid metals and associated aspects, on subcritical reactor physics and subsequently on applications such as nuclear waste transmutation, radioisotope production and safety research on sub-critical systems. The MYRRHA system is intended to be a multipurpose R&D facility and is expected to become a new major research infrastructure for the European partners presently involved in the ADS Demo development. Ion Beam Applications is performing the accelerator development. Currently the preliminary conceptual design of the MYRRHA system is under way and an intensive R&D programme is assessing the points of greatest risk in the present design. This work will define the final choice of characteristics of the facility. In this paper, we will report on the status of the pre-design study as of June 2000 as well as on the methods and results of the R&D programme.

  20. Development of the plane wave transformer photoelectron linear accelerator

    NASA Astrophysics Data System (ADS)

    Ding, Xiaodong

    2000-11-01

    The design, fabrication and characterization of the UCLA integrated S-Band RF photocathode electron linear accelerator (Linac) based on the plane wave transformer (PWT) structure is presented. This new generation photoinjector integrates a photocathode directly into a PWT linac making the structure simple and compact. Due to the strong coupling between each adjacent cell, the PWT structure is relatively easy to fabricate and operate. This photoinjector can provide high brightness beams at energies of 15 to 20MeV, with emittance less than 1mm.mrad at charge of 1 nC [3]. These short-pulse beams can be used in various applications: space charge dominated beam physics studies, plasma lenses, plasma accelerators, free-electron laser microbunching techniques, and SASE-FEL physics studies. It will also provide commercial opportunities in chemistry, biology and medicine. The principle of photoelectron gun setup, accelerating structure design and beam dynamic study is described. The design, fabrication and testing of this UCLA 10 full cell and 2 half cell PWT structure is discussed in detail. The results of Microwave measurements and first step high power test have showed the success of the UCLA PWT photoinjector design. The measurement results met all the design goals and operation requirements. The experimental requirements for the beam diagnostics are also presented.

  1. An optimized slab-symmetric dielectric-based laser accelerator structure

    SciTech Connect

    Rosenzweig, J. B.; Schoessow, P. V.

    1999-10-21

    A slab-symmetric, partially dielectric filled, laser excited structure which maybe used to accelerate charged particles is analyzed theoretically and computationally. The fields associated with the accelerating mode are calculated, as are aspects of the resonant filling and impedance matching of the structure to the exciting laser. It is shown through computer simulation that the accelerating mode in this structure can be excited resonantly and with large quality factor Q. Practical aspects of implementing this structure as an accelerator are discussed.

  2. 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.

  3. 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.

  4. Acceleration of drug development: a collaboration of many stakeholders.

    PubMed

    Reynolds, K S

    2013-06-01

    Modern drugs are used to treat and prevent diseases that previously led to morbidity and mortality. There is a high cost to this achievement--investment for each successful drug can exceed $1.8 billion. Late-phase drug candidate failure decreases efficiency of drug development because each failure represents lost or delayed opportunity to develop successful drugs. Collaboration of stakeholders and the use of new science and knowledge management can reduce late-phase failure and accelerate drug development.

  5. Multipactor discharge in a dielectric-loaded accelerating structure

    NASA Astrophysics Data System (ADS)

    Wu, L.; Ang, L. K.

    2007-01-01

    This paper presents a Monte-Carlo model to explain the multipactor discharge and its high-power absorption in a dielectric-loaded accelerating (DLA) structure reported recently [J. G. Power et al., Phys. Rev. Lett. 92, 164801 (2004)]. Susceptibility diagrams are constructed. Dynamic calculations for beam loading and its power absorption by the multipactor discharge are performed. It is found that the fraction of power absorbed by multipactor discharge at saturation is much larger than the case of a simple rf window, and it is sensitive to the incident power, which confirms the prior experimental results. This enhanced power absorption is due to the fact that the length of a DLA structure is much larger than the radius of the structure. A resonant condition of a maximum growth region has also been determined numerically and analytically. The difference between the resonant condition and saturation (due to beam loading) is clarified.

  6. RF measurements of a traveling-wave muffin-tin accelerating structure at 90 GHz

    SciTech Connect

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

    1997-05-01

    A measuring system at the table-top scale was developed for RF measurements of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz). Both perturbation and non-perturbation methods are employed to characterize the RF properties of a muffin-tin structure. Conventional bead pull measurements are extended to millimeter wavelengths. Design of the measuring system and preliminary results of RF measurements are presented.

  7. Accelerating Dynamic Cardiac MR Imaging Using Structured Sparse Representation

    PubMed Central

    Cai, Nian; Wang, Shengru; Zhu, Shasha

    2013-01-01

    Compressed sensing (CS) has produced promising results on dynamic cardiac MR imaging by exploiting the sparsity in image series. In this paper, we propose a new method to improve the CS reconstruction for dynamic cardiac MRI based on the theory of structured sparse representation. The proposed method user the PCA subdictionaries for adaptive sparse representation and suppresses the sparse coding noise to obtain good reconstructions. An accelerated iterative shrinkage algorithm is used to solve the optimization problem and achieve a fast convergence rate. Experimental results demonstrate that the proposed method improves the reconstruction quality of dynamic cardiac cine MRI over the state-of-the-art CS method. PMID:24454528

  8. 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…

  9. 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…

  10. 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.

  11. Investigation of Beam-RF Interactions in Twisted Waveguide Accelerating Structures Using Beam Tracking Codes

    SciTech Connect

    Holmes, Jeffrey A; Zhang, Yan; Kang, Yoon W; Galambos, John D; Hassan, Mohamed H; Wilson, Joshua L

    2009-01-01

    Investigations of the RF properties of certain twisted waveguide structures show that they support favorable accelerating fields. This makes them potential candidates for accelerating cavities. Using the particle tracking code, ORBIT, We examine the beam - RF interaction in the twisted cavity structures to understand their beam transport and acceleration properties. The results will show the distinctive properties of these new structures for particle transport and acceleration, which have not been previously analyzed.

  12. International X-Band Linear Collider Accelerator Structure R&D

    SciTech Connect

    Wang, J.W.; /SLAC

    2009-03-04

    For more than fifteen years before the International Technology Recommendation Panel (ITRP) decision in August, 2004, there were intensive R&D activities and broad international collaboration among the groups at SLAC, KEK, FNAL, LLNL and other labs for the room temperature X-Band accelerator structures. The goal was to provide an optimized design of the main linac structure for the NLC (Next Linear Collider) or GLC (Global Linear Collider). There have been two major challenges in developing X-band accelerator structures for the linear colliders. 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. More than thirty X-band accelerator structures with various RF parameters, cavity shapes and coupler types have been fabricated and tested since 1989. A summary of the main achievements and experiences are presented in this talk including the structure design, manufacturing techniques, high power performance, and other structure related issues. Also, the new progress in collaborating with the CLIC, high gradient structures and X-Band structure applications for RF deflectors and others are briefly introduced.

  13. Niobium resonator development for high-brightness ion beam acceleration

    SciTech Connect

    Delayen, J.R.; Bohn, C.L.; Roche, C.T.

    1990-01-01

    Two niobium resonant cavities for high-brightness ion beam acceleration have been constructed and tested. The first was based on a coaxial quarter-wave geometry and was optimized for phase velocity {beta}{sub o} = 0.15. This cavity, which resonates at 400 MHz in the fundamental mode, operated at an average (wall-to-wall) accelerating gradient of 12.9 MV/m under continuous-wave (cw) fields. At this gradient, a cavity Q of 1.4 {times} 10{sup 8} was measured. The second was based on a coaxial half-wave geometry and was optimized for {beta}{sub o} = 0.12. This cavity, which resonates at 355 MHz in the fundamental mode, operated at an average accelerating gradient of 18.0 MV/m under cw fields. This is the highest average accelerating gradient achieved to date in low-velocity structures designed for cw operation. At this gradient, a cavity Q of 1.2 {times} 10{sup 8} was measured.

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

    DOE PAGES

    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. 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

  15. 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.

  16. 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.

  17. Development of a Dielectric-Loaded Accelerator Test Facility Based on an X-Band Magnicon Amplifier

    SciTech Connect

    Gold, S. H.; Fliflet, A. W.; Kinkead, A. K.; Gai, W.; Power, J. G.; Konecny, R.; Jing, C.; Tantawi, S. G.; Nantista, C. D.; Hu, Y.; Du, X.; Tang, C.; Lin, Y.; Bruce, R. W.; Bruce, R. L.; Lewis, D. III

    2006-01-03

    The Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), are developing a dielectric-loaded accelerator (DLA) test facility powered by the 11.424-GHz magnicon amplifier that was developed jointly by NRL and Omega-P, Inc. Thus far, DLA structures developed by ANL have been tested at the NRL Magnicon Facility without injected electrons, including tests of alumina and magnesium calcium titanate structures at gradients up to {approx}8 MV/m. The next step is to inject electrons in order to build a compact DLA test accelerator. The Accelerator Laboratory of Tsinghua University in Beijing, China has developed a 5-MeV electron injector for the accelerator, and SLAC is developing a means to combine the two magnicon output arms, and to drive the injector and an accelerator section with separate control of the power ratio and relative phase. Also, RWBruce Associates, working with NRL, is developing a means to join ceramic tubes to produce long accelerating sections using a microwave brazing process. The installation and commissioning of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year.

  18. Design of 57.5 MHz cw RFQ structure for the rare isotope accelerator facility.

    SciTech Connect

    Ostroumov, P. N.; Kolomiets, A. A.; Kashinsky, D. A.; Minaev, S. A.; Pershin, V. I.; Yaramishev, S. G.; Tretyakova, T. E.

    2002-01-29

    The Rare Isotope Accelerator (RIA) facility includes a driver linac for production of 400 kW CW heavy-ion beams. The initial acceleration of heavy-ions delivered from an ECR ion source can be effectively performed by a 57.5 MHz four-meter long RFQ. The principal specifications of the RFQ are: (1) formation of extremely low longitudinal emittance; (2) stable operation over a wide range of voltage for acceleration of various ion species needed for RIA operation; (3) simultaneous acceleration of two-charge states of uranium ions. CW operation of an accelerating structure leads to a number of requirements for the resonators such as high shunt impedance, efficient water cooling of all parts of the resonant cavity, mechanical stability together with precise alignment, reliable rf contacts, a stable operating mode and fine tuning of the resonant frequency during operation. To satisfy these requirements a new resonant structure has been developed. This paper discusses beam dynamics and electrodynamics design of the RFQ cavity, as well as, some aspects of the mechanical design of this low-frequency CW RFQ.

  19. 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. PMID:27522919

  20. 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.

  1. 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.

  2. 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

  3. H-mode Accelerating Structures with PMQ Focusing for Low-Beta Beams

    SciTech Connect

    Kurennoy, Sergey S.; O'Hara, James F.; Olivas, Eric R.; Rybarcyk, Lawrence J.

    2011-01-01

    We report on results of the project developing high-efficiency normal-conducting RF accelerating structures based on inter-digital H-mode (IH) cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of IH-PMQ structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. The H-PMQ accelerating structures following a short RFQ can be used both in the front end of ion linacs or in stand-alone applications. Results of the combined 3-D modeling -- electromagnetic computations, beam-dynamics simulations with high currents, and thermal-stress analysis -- for a full IH-PMQ accelerator tank are presented. The accelerating field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of EM and beamdynamics modeling. Multi-particle simulations withParmela and CST Particle Studio have been used to confirm the design. Measurement results of a cold model of the IH-PMQ tank are presented.

  4. 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.

  5. 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.

  6. 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.

  7. High-Power Accelerator Research and Development at the NRL 11.424-GHz Magnicon Facility

    NASA Astrophysics Data System (ADS)

    Gold, Steven H.; Kinkead, Allen K.; Nezhevenko, Oleg A.; Yakovlev, Vyacheslav P.; Hirshfield, Jay L.; Vikharev, Anatoly; Ivanov, Oleg; Kuzikov, Sergey; Gorbachev, Alexey; Isaev, Vladimir A.; Gai, Wei; Power, John G.; Konecny, Richard

    2002-11-01

    An 11.424-GHz magnicon amplifier has been jointly developed by the Naval Research Laboratory and Omega-P, Inc. as an alternative technology to klystrons for powering a future X-band linear collider. This paper will discuss its background, operating principles, and results to date, as well its present status as a facility for collaborative research on accelerator-related technologies that require high-power 11.424-GHz radiation. Two research programs are currently under way using the output of the magnicon. The first, a collaboration with Omega-P, Inc. and the Institute of Applied Physics, is investigating active microwave pulse compressors using plasma switch tubes. The second, a collaboration with Argonne National Laboratory and SLAC, is investigating dielectric-loaded accelerating (DLA) structures, with the ultimate goal of developing a compact DLA accelerator.

  8. 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.

  9. [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.

  10. [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. PMID:27149748

  11. THE SPECIFIC ACCELERATION RATE IN LOOP-STRUCTURED SOLAR FLARES-IMPLICATIONS FOR ELECTRON ACCELERATION MODELS

    SciTech Connect

    Guo, Jingnan; Emslie, A. Gordon; Piana, Michele E-mail: piana@dima.unige.it

    2013-03-20

    We analyze electron flux maps based on RHESSI hard X-ray imaging spectroscopy data for a number of extended coronal-loop flare events. For each event, we determine the variation of the characteristic loop length L with electron energy E, and we fit this observed behavior with models that incorporate an extended acceleration region and an exterior 'propagation' region, and which may include collisional modification of the accelerated electron spectrum inside the acceleration region. The models are characterized by two parameters: the plasma density n in, and the longitudinal extent L{sub 0} of, the acceleration region. Determination of the best-fit values of these parameters permits inference of the volume that encompasses the acceleration region and of the total number of particles within it. It is then straightforward to compute values for the emission filling factor and for the specific acceleration rate (electrons s{sup -1} per ambient electron above a chosen reference energy). For the 24 events studied, the range of inferred filling factors is consistent with a value of unity. The inferred mean value of the specific acceleration rate above E{sub 0} = 20 keV is {approx}10{sup -2} s{sup -1}, with a 1{sigma} spread of about a half-order-of-magnitude above and below this value. We compare these values with the predictions of several models, including acceleration by large-scale, weak (sub-Dreicer) fields, by strong (super-Dreicer) electric fields in a reconnecting current sheet, and by stochastic acceleration processes.

  12. Theoretical Investigations of Plasma-Based Accelerators and Other Advanced Accelerator Concepts

    SciTech Connect

    Shuets, G.

    2004-05-21

    Theoretical investigations of plasma-based accelerators and other advanced accelerator concepts. The focus of the work was on the development of plasma based and structure based accelerating concepts, including laser-plasma, plasma channel, and microwave driven plasma accelerators.

  13. 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.

  14. [Acceleration of somatic development in the surroundings of zinc plant].

    PubMed

    Torbus, Onufry; Grzywna, Teresa; Grzywna, Ewa

    2002-01-01

    One of the most sensitive measures of health state depending on for example social conditions of the society and family as well as the degree of environmental pollution is somatic development of children. Changes in the somatic and descriptive values, which have been observed for the decades, are known as secular trend that is tendency for changes over centuries. One of its parts is enlargement of parameters of somatic development that is acceleration. Numerous studies on the development of children living in Silesia, the area of great economic potential, however, highly polluted, show the deterioration of developmental parameters of children in Silesia in comparison with their peers from other parts of Poland. The aim of the study is to evaluate the acceleration of somatic development of children living nearby zinc plant. Studies on the somatic development of children at the age between 7-15 years attending the same primary school were carried out in Miasteczko Slaskie at interval of 15 years (1983-1998). Miasteczko Slaskie is the town known for its zinc plant that emits the highest levels of pollution of all steelworks in Poland. This is related to metallurgy of non-ferrous metals. The results were compared with the results of body measurement of the peers from one of the schools in Tarnowskie Góry carried out in the years 1988 and 1998. It was shown that boys and girls from both communities presented lower body mass and height in all periods of study than the standards of The Institute of Mother and Child showed in 1983. No acceleration of somatic development was present among children in Tarnowskie Góry, which may be explained by deterioration of social conditions of these children. However, this acceleration is present in the population of children in Miasteczko Slaskie. This fact may be explained by significantly decreased emission of pollution by the zinc plant and intense care for children shown by the plant managers as well as the foundation for children

  15. 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.

  16. 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

  17. Temporal Development of Auroral Acceleration Potentials: High-Altitude Evolutionary Sequences, Drivers and Consequences

    NASA Astrophysics Data System (ADS)

    Hull, A. J.; Wilber, M.; Chaston, C.; Bonnell, J.; Mozer, F.; McFadden, J.; Goldstein, M.; Fillingim, M.

    2007-12-01

    The region above the auroral acceleration region is an integral part of the auroral zone electrodynamic system. At these altitudes (≥ 3 Re) we find the source plasma and fields that determine acceleration processes occurring at lower altitudes, which play a key role in the transport of mass and energy into the ionosphere. Dynamic changes in these high-altitude regions can affect and/or control lower-altitude acceleration processes according to how field-aligned currents and specific plasma sources form and decay and how they are spatially distributed, and through magnetic configuration changes deeper in the magnetotail. Though much progress has been made, the time development and consequential effects of the high-altitude plasma and fields are still not fully understood. We present Cluster multi-point observations at key instances within and above the acceleration region (> 3 RE) of evolving auroral arc current systems. Results are presented from events occurring under different conditions, such as magnetospheric activity, associations with density depletions or gradients, and Alfvenic turbulence. A preliminary survey, primarily at or near the plasma sheet boundary, indicates quasi- static up-down current pair systems are at times associated with density depletions and other instances occur in association with density gradients. The data suggest that such quasi-static current systems may be evolving from structured Alfvenic current systems. We will discuss the temporal development of auroral acceleration potentials, plasma and currents, including quasi-static system formation from turbulent systems of structured Alfvenic field-aligned currents, density depletion and constituent reorganization of the source and ionospheric plasma that transpire in such systems. Of particular emphasis is how temporal changes in magnetospheric source plasma and fields affect the development of auroral acceleration potentials at lower altitudes.

  18. Parallel Computation of Intergrated Electronmagnetic, Thermal and Structural Effects for Accelerator Cavities

    SciTech Connect

    Akcelik, V.; Candel, A.; Kabel, A.; Lee, L-Q.; Li, Z.; Ng, C-K.; Xiao, L.; Ko, K.

    2008-07-02

    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.

  19. 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.

  20. 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.

  1. 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.

  2. Latest Diagnostic Electronics Development for the PROSCAN Proton Accelerator

    NASA Astrophysics Data System (ADS)

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

    2004-11-01

    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.

  3. Development of the accelerator-driven energy production concept

    SciTech Connect

    Venneri, F.; Beard, C.; Bowman, C.

    1996-10-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Accelerator Driven Transmutation Technology (ADTT) offers a means of generating nuclear energy in a clean, safe way that can be attractive to the general public. However, there are issues associated with the energy story (both at the system level and technical detail) that have to be seriously addressed before the scientific community, the public, and potential industrial sponsors can be compellingly convinced of its cost/benefit.

  4. Design study of double-layer beam trajectory accelerator based on the Rhodotron structure

    NASA Astrophysics Data System (ADS)

    Jabbari, Iraj; Poursaleh, Ali Mohammad; Khalafi, Hossein

    2016-08-01

    In this paper, the conceptual design of a new structure of industrial electron accelerator based on the Rhodotron accelerator is presented and its properties are compared with those of Rhodotron-TT200 accelerator. The main goal of this study was to reduce the power of RF system of accelerator at the same output electron beam energy. The main difference between the new accelerator structure with the Rhodotron accelerator is the length of the coaxial cavity that is equal to the wavelength at the resonant frequency. Also two sets of bending magnets were used around the acceleration cavity in two layers. In the new structure, the beam crosses several times in the coaxial cavity by the bending magnets around the cavity at the first layer and then is transferred to the second layer using the central bending magnet. The acceleration process in the second layer is similar to the first layer. Hence, the energy of the electron beam will be doubled. The electrical power consumption of the RF system and magnet system were calculated and simulated for the new accelerator structure and TT200. Comparing the calculated and simulated results of the TT200 with those of experimental results revealed good agreement. The results showed that the overall electrical power consumption of the new accelerator structure was less than that of the TT200 at the same energy and power of the electron beam. As such, the electrical efficiency of the new structure was improved.

  5. 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.

  6. 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.

  7. A semi-automated system for the characterization of NLC accelerating structures

    SciTech Connect

    Hanna, S.M.; Bowden, G.B.; Hoag, H.A.; Loewen, R.; Vlieks, A.E.; Wang, J.W.

    1995-06-01

    *A system for characterizing the phase shift per cell of a long X-band accelerator structure is described. The fields within the structure are perturbed by a small cylindrical metal bead pulled along the axis. A computer controls the bead position and processes the data from a network analyzer connected to the accelerator section. Measurements made on prototype accelerator sections are described, and they are shown to be in good agreement with theory.

  8. Development of turbocharger for improving passenger car acceleration

    SciTech Connect

    Watanabe, Tsuyoshi; Koike, Takaaki; Furukawa, Hiromu; Ikeya, Nobuyuki; Sakakida, Masaru

    1996-09-01

    Recently, passenger cars require better acceleration from low engine speed including starting-up in order to decrease the amount of particulate matter (PM) of diesel engines or to improve the driver`s feeling. However, turbocharged cars generally have worse response than the non turbo cars because it takes a few seconds to get the turbocharger rotate up to high speed, usually called Turbo-lag. In order to solve this, various technologies have been developed for a turbocharger itself as well as for charging system such as the sequential system. Here in this paper, the authors focus on the development of the following turbocharger technology to reduce Turbo-lag and to achieve better transient response.

  9. 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

  10. 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.

  11. 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.

  12. Bmp2 and Bmp4 accelerate alveolar bone development.

    PubMed

    Ou, Mingming; Zhao, Yibing; Zhang, Fangming; Huang, Xiaofeng

    2015-06-01

    Alveolar bone remodeling is a continuous process that takes place during development and in response to various physiological and pathological stimuli. However, detailed knowledge regarding the underlying mechanisms involved in alveolar bone development is still lacking. This study aims at improving our understanding of alveolar bone formation and the role of bone morphogenetic proteins (Bmps) in this process. Mice at embryonic (E) day 13.5 to postnatal (PN) day 15.5 were selected to observe the process of alveolar bone development. Alveolar bone development was found to be morphologically observable at E14.5. Molar teeth isolated from mice at PN7.5 were pretreated with Bmp2, Bmp4, Noggin, or BSA, and grafted subcutaneously into mice. The subcutaneously implanted tooth germs formed alveolar bone indicating the role of the dental follicle in alveolar bone development. Alveolar bone formation was increased after pretreatment with Bmp2 and Bmp4, but not with Noggin. Gene expression levels in dental follicle cells from murine molars were also determined by real-time RT-PCR. The expression levels of Runx2, Bsp, and Ocn were significantly higher in dental follicle cells cultured with Bmp2 or Bmp4, and significantly lower in those cultured with Noggin when compared with that of the BSA controls. Our results suggest that the dental follicle participates in alveolar bone formation and Bmp2/4 appears to accelerate alveolar bone development.

  13. 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.

  14. 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. PMID:23155997

  15. 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.

  16. 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.

  17. Development of an Accelerator Mass Spectrometer based on a Cyclotron

    SciTech Connect

    Kim, Dogyun; Bhang, Hyeongchan; Kim, Jongwon

    2011-12-13

    An accelerator mass spectrometer based on a cyclotron has been developed, and a prototype of the injection beam line has been constructed. Mass resolution of the cyclotron is designed to be over 4000. A sawtooth RF buncher in the beam line and a flat-topping RF system for the cyclotron were utilized to enhance beam transmission efficiency, which is a primary factor for improvement compared to previous cyclotron mass spectrometers. The injection beam line comprises an ion source, Einzel lens, RF buncher, 90 deg. dipole magnet and a slit box containing beam diagnostic devices. A carbon beam was measured at the location of the slit box, and beam phase spaces will be measured. The design of a cyclotron magnet was done, and orbit tracking was carried out using cyclotron optics codes. A scheme of radial injection was chosen to place a beam on the equilibrium orbit of the cyclotron. The injection scheme will be optimized after the beam measurements are completed.

  18. Status and Future Developments in Large Accelerator Control Systems

    SciTech Connect

    Karen S. White

    2006-10-31

    Over the years, accelerator control systems have evolved from small hardwired systems to complex computer controlled systems with many types of graphical user interfaces and electronic data processing. Today's control systems often include multiple software layers, hundreds of distributed processors, and hundreds of thousands of lines of code. While it is clear that the next generation of accelerators will require much bigger control systems, they will also need better systems. Advances in technology will be needed to ensure the network bandwidth and CPU power can provide reasonable update rates and support the requisite timing systems. Beyond the scaling problem, next generation systems face additional challenges due to growing cyber security threats and the likelihood that some degree of remote development and operation will be required. With a large number of components, the need for high reliability increases and commercial solutions can play a key role towards this goal. Future control systems will operate more complex machines and need to present a well integrated, interoperable set of tools with a high degree of automation. Consistency of data presentation and exception handling will contribute to efficient operations. From the development perspective, engineers will need to provide integrated data management in the beginning of the project and build adaptive software components around a central data repository. This will make the system maintainable and ensure consistency throughout the inevitable changes during the machine lifetime. Additionally, such a large project will require professional project management and disciplined use of well-defined engineering processes. Distributed project teams will make the use of standards, formal requirements and design and configuration control vital. Success in building the control system of the future may hinge on how well we integrate commercial components and learn from best practices used in other industries.

  19. Expanding research capacity and accelerating AIDS vaccine development in Asia.

    PubMed

    Excler, Jean-Louis; Pitisuttithum, Punnee; Rerks-Ngarm, Supachai; Shao, Yiming; Zhang, Linqi; Tamashiro, Hiko; Osmanov, Saladin

    2008-07-01

    According to the Joint UN Program on AIDS (UNAIDS), an estimated 4.9 million adults and children are living with HIV in Asia and the Pacific. Refinement and development of existing and new prevention and treatment technologies--including safe, effective, and accessible AIDS vaccines--are urgent public health priorities. The Asian region faces several challenges for AIDS vaccine development. There are multiple genetic variants of HIV-1 driving the epidemic in the region and too few vaccine candidates in the pipeline targeting those subtypes. Low HIV incidence throughout the region means that trial sites must recruit larger numbers of volunteers and shift their focus to higher-risk populations where incidence is higher. Also, the cultural, economic, and political diversity of the region may render collaboration very complex, but also beneficial at a regional level. Recognizing that collaborating as a region could foster and accelerate AIDS vaccine development, participants at the Sapporo International Consultation recommended that an AIDS Vaccine Asian Network (AVAN) be created to facilitate interactions between donors and funding opportunities, increase regional clinical trial and production capacity, support region-specific advocacy and communication strategies, contribute to the Global HIV Vaccine Enterprise Scientific Plan, prepare a regional approach for future vaccine deployment, and develop a regional platform for clinical trials including harmonized legal, regulatory, and ethical frameworks. PMID:19058617

  20. Auroral ion acceleration from lower hybrid solitary structures: A summary of sounding rocket observations

    NASA Astrophysics Data System (ADS)

    Lynch, K. A.; Arnoldy, R. L.; Kintner, P. M.; Schuck, P.; Bonnell, J. W.; Coffey, V.

    In this paper we present a review of sounding rocket observations of the ion acceleration seen in nightside auroral zone lower hybrid solitary structures. Observations from Topaz3, Amicist, and Phaze2 are presented on various spatial scales, including the two-point measurements of the Amicist mission. From this collection of observations we will demonstrate the following characteristics of transverse acceleration of ions (TAI) in lower hybrid solitary structures (LHSS). The ion acceleration process is narrowly confined to 90° pitch angle, in spatially confined regions of up to a few hundred meters across B. The acceleration process does not affect the thermal core of the ambient distribution and does not directly create a measurable effect on the ambient ion population outside the LHSS themselves. This precludes observation with these data of any nonlinear feedback between the ion acceleration and the existence or evolution of the density irregularities on which these LHSS events grow. Within the LHSS region the acceleration process creates a high-energy tail beginning at a few times the thermal ion speed. The ion acceleration events are closely associated with localized wave events. Accelerated ions bursts are also seen without a concurrent observation of a localized wave event, for two possible reasons. In some cases, the pitch angles of the accelerated tail ions are elevated above perpendicular; that is, the acceleration occurred below the observer and the mirror force has begun to act upon the distribution, moving it upward from the source. In other cases, the accelerated ion structure is spatially larger than the wave event structure, and the observation catches only the ion event. The occurrence rate of these ion acceleration events is related to the ambient environment in two ways: its altitude dependence can be modeled with the parameter B2/ne, and it is highest in regions of intense VLF activity. The cumulative ion outflow from these LHSS TAI is

  1. 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.

  2. LIGA fabrication of mm-wave accelerating cavity structures at the Advanced Photon Source (APS)

    SciTech Connect

    Song, J.J.; Bajikar, S.; Kang, Y.W.

    1997-08-01

    Recent microfabrication technologies based on the LIGA (German acronym for Lithographe, Galvanoformung, und Abformung) process have been applied to build high-aspect-ratio, metallic or dielectric planar structures suitable for high-frequency rf cavity structures. The cavity structures would be used as parts of linear accelerators, microwave undulators, and mm-wave amplifiers. The microfabrication process includes manufacture of precision x-ray masks, exposure of positive resist x-rays through the mask, resist development, and electroforming of the final microstructure. Prototypes of a 32-cell, 108-GHz constant-impedance cavity and a 66-cell, 94-GHz constant-gradient cavity were fabricated with the synchrotron radiation sources at APS and NSLS. This paper will present an overview of the new technology and details of the mm-wave cavity fabrication.

  3. 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.

  4. 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).

  5. 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. PMID:26809562

  6. 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.

  7. 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.

  8. 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.

  9. Potential structures and particle acceleration on auroral field lines

    NASA Astrophysics Data System (ADS)

    Gorney, D. J.

    1985-05-01

    In the 1970's major advances in the understanding of auroral processes were brought about by observations of plasmas and electric fields within the regions of space responsible for auroral particle acceleration. The major contribution of these observations was the verification of the existence of electric fields with components parallel to the magnetic field over large regions of altitude (1000 to 20000 kilometers). These electric fields constitute potential drops of several kilovolts, accelerating magnetospheric electrons downward to form the aurora and ionospheric ions upward, where they contribute significantly to the magnetospheric hot ion population. Perpendicular spatial scales of about 100 kilometers are most common, although finer scales have been observed embedded, and individual small amplitude double layers occur on much smaller parallel spatial scales. More recently, the same data sets have revealed the existance of about 100 V electric potential drops directed downward in return current regions. Downward electric fields are in a direction to accelerate electrons out of the ionsphere and tend to retard the propagation of ions upward. An association between upflowing electron beams and transversely heated ions at low altitude has been noted, and a casual relationship between downward electric fields and ion conics is suggested.

  10. Dielectric Wakefield Accelerating Structure as a Source of Terahertz Coherent Cerenkov Radiation

    SciTech Connect

    Cook, A. M.; Rosenzweig, J. B.; Badakov, H.; Travish, G.; Tikhoplav, R.; Williams, O. B.; England, R. J.; Thompson, M. C.

    2006-11-27

    We discuss future experimental work proposed to study the performance of a cylindrical dielectric wakefield accelerating structure as a coherent Cerenkov radiation source at the Neptune laboratory at UCLA. The Cerenkov wakefield acceleration experiment carried out recently by UCLA/SLAC/USC, using the ultrashort and high charge beam (Q = 3 nC, {sigma}z = 20 micron) at the SLAC FFTB, demonstrated electromagnetic wakes at the few GV/m level. The motivation of our prospective experiment is to investigate the operation of a similar scenario using the comparatively long pulse, low charge beam (Q = 0.5 nC, {sigma}z = 200 micron) at UCLA Neptune. The field amplitude produced in this setup would be one to two orders of magnitude lower, at the few tens to few 100 MV/m level. Such a decelerating field would extract a significant amount of energy from a low-energy beam in a distance on the order of a few centimeters, allowing the use of short dielectric structures. We discuss details of the geometry and composition of the structures to be used in the experiment. We also examine the possibility of a future dedicated facility at UCLA Neptune based on a hybrid photoinjector currently in development. The intrinsic bunch compression capabilities and improved beam parameters ({sigma}z = 100 micron, Q = 1 nC) of the photoinjector would allow the creation of a high power radiation source in the terahertz regime.

  11. Fernald - Developing and Executing an Accelerated Closure Plan

    SciTech Connect

    Nixon, D.A.

    2006-07-01

    In November 2000 the Department of Energy (DOE) and Fluor Fernald entered into a closure contract that incited Fluor Fernald to reduce the cost and schedule of the Fernald site cleanup. The contract established a target schedule and target cost and how Fluor Fernald performs against these targets determines the amount of fee the company earns. In response to these new challenges, Fluor Fernald developed a 13-part strategy to safely accelerate work and more efficiently utilize the available funding. Implementation of this strategy required a dramatic culture change at Fernald - from a 'government job mind set' to an entrepreneurial/commercial model. Fluor Fernald's strategy and culture change has proved to be successful as the company is on track to close the site ahead of the target schedule at a total project cost less than the target cost. The elements of Fluor Fernald's strategy and the lessons learned during implementation provide valuable information that could be utilized by other DOE sites that will be undergoing closure over the next decade. (authors)

  12. 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.

  13. 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.

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

    DOE PAGES

    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 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

  15. 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.

  16. 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

  17. 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. PMID:27420300

  18. 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. PMID:21541963

  19. 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.

  20. Potential structures and particle acceleration on auroral field lines

    NASA Astrophysics Data System (ADS)

    Gorney, D. J.

    Observations of plasmas and electric field activity within regions of auroral particle acceleration have verified the existence of electric fields with components parallel to the magnetic field over large altitude regions. Evidence is presented which indicates that small-ampliatude double layers along the auroral magnetic field lines may provide a mechanism for the maintenance of auroral ion potential. Evidence is also presented of downward-directed parallel electric fields along the magnetic field lines in the return current region. It is suggested that the downward electric fields may have significant effects on ion trajectories, and further theoretical investigation of the effects of downward parallel electric fields on ion conic formation is recommended.

  1. Cold test results of a side-coupled standing-wave electron-accelerating structure

    NASA Astrophysics Data System (ADS)

    Song, Ki Baek; Li, Yonggui; Lee, Sanghyun; Lee, Byeong-No; Park, Hyung Dal; Cha, Sung-Su; Lee, Byung Cheol

    2013-07-01

    The radio-frequency (RF) cavity for the dual-energy S-band electron linear accelerator (LINAC) is designed for a cargo inspection system (CIS) at the Korea Atomic Energy Research Institute (KAERI). The cold test results of the electron accelerator structure, which has a side-coupled standing-wave interlaced-pulse dual-energy mode, are described. The design concept, basic structure, microwave-tuning method, and cold-test procedure are described as well. The measured dispersion curve, spectrum characteristics, ρ-f relation of the power coupler, and axial field distribution of the accelerating gradient are provided.

  2. On using moving windows in finite element time domain simulation for long accelerator structures

    SciTech Connect

    Lee, L.-Q.; Candel, Arno; Ng, Cho; Ko, Kwok

    2010-12-10

    A finite element moving window technique is developed to simulate the propagation of electromagnetic waves induced by the transit of a charged particle beam inside large and long structures. The window moving along with the beam in the computational domain adopts high-order finite element basis functions through p refinement and/or a high-resolution mesh through h refinement so that a sufficient accuracy is attained with substantially reduced computational costs. Algorithms to transfer discretized fields from one mesh to another, which are the keys to implementing a moving window in a finite element unstructured mesh, are presented. Numerical experiments are carried out using the moving window technique to compute short-range wakefields in long accelerator structures. The results are compared with those obtained from the normal finite element time domain (FETD) method and the advantages of using the moving window technique are discussed.

  3. Using pattern enumeration to accelerate process development and ramp yield

    NASA Astrophysics Data System (ADS)

    Zhuang, Linda; Pang, Jenny; Xu, Jessy; Tsai, Mengfeng; Wang, Amy; Zhang, Yifan; Sweis, Jason; Lai, Ya-Chieh; Ding, Hua

    2016-03-01

    During a new technology node process setup phase, foundries do not initially have enough product chip designs to conduct exhaustive process development. Different operational teams use manually designed simple test keys to set up their process flows and recipes. When the very first version of the design rule manual (DRM) is ready, foundries enter the process development phase where new experiment design data is manually created based on these design rules. However, these IP/test keys contain very uniform or simple design structures. This kind of design normally does not contain critical design structures or process unfriendly design patterns that pass design rule checks but are found to be less manufacturable. It is desired to have a method to generate exhaustive test patterns allowed by design rules at development stage to verify the gap of design rule and process. This paper presents a novel method of how to generate test key patterns which contain known problematic patterns as well as any constructs which designers could possibly draw based on current design rules. The enumerated test key patterns will contain the most critical design structures which are allowed by any particular design rule. A layout profiling method is used to do design chip analysis in order to find potential weak points on new incoming products so fab can take preemptive action to avoid yield loss. It can be achieved by comparing different products and leveraging the knowledge learned from previous manufactured chips to find possible yield detractors.

  4. 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.

  5. 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.

  6. A mm-wave planar microcavity structure for electron linear accelerator system

    SciTech Connect

    Kang, Y.W.; Kustom, R.; Mills, F.; Mavrogenes, G.; Henke, H.

    1993-07-01

    The muffin-tin cavity structure is planar and well suited for mm-wave accelerator with silicon etching techniques. A constant impedance traveling-wave structure is considered for design simplicity. The RF parameters are calculated and the shunt impedance is compared with the shunt impedance of a disk loaded cylindrical structure.

  7. 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.

  8. 2D and 3D multipactor modeling in dielectric-loaded accelerator structures

    NASA Astrophysics Data System (ADS)

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas

    2010-11-01

    Multipactor (MP) is known as the avalanche growth of the number of secondary electrons emitted from a solid surface exposed to an RF electric field under vacuum conditions. MP is a severe problem in modern rf systems and, therefore, theoretical and experimental studies of MP are of great interest to the researchers working in various areas of physics and engineering. In this work we present results of MP studies in dielectric-loaded accelerator (DLA) structures. First, we show simulation results obtained with the use of the 2D self-consistent MP model (O. V. Sinitsyn, et. al., Phys. Plasmas, vol. 16, 073102 (2009)) and compare those to experimental ones obtained during recent extensive studies of DLA structures performed by Argonne National Laboratory, Naval Research Laboratory, SLAC National Accelerator Laboratory and Euclid TechLabs (C. Jing, et al., IEEE Trans. Plasma Sci., vol. 38, pp. 1354-1360 (2010)). Then we present some new results of 3D analysis of MP which include studies of particle trajectories and studies of MP development at the early stage.

  9. Laser Acceleration in Vacuum with an Open Iris-Loaded Structure

    SciTech Connect

    Xie, Ming

    1997-07-01

    An open iris-loaded waveguide structure is considered for laser acceleration of highly relativistic particle in vacuum. Complete characterization of eigenmodes are given in analytical form for the structure. In particular acceleration performance of the dominant TM mode is evaluated in detail. Transparent scaling laws are derived, and through which significant advantages over other vacuum laser acceleration schemes are demonstrated. The entire parameter space is searched and it is found that below the laser damage threshold of the structure an acceleration gradient around 1 GV/m can be obtained over a phase slippage length of 10s of cm with TWs laser in the wavelength range from 1 to 10 {micro}m.

  10. 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.

  11. 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.

  12. 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.

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

    DOE PAGES

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

    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

  14. Developing and Maintaining Accelerated Degree Programs within Traditional Institutions.

    ERIC Educational Resources Information Center

    Husson, William J.; Kennedy, Tom

    2003-01-01

    Successful accelerated degree programs should be learner focused, market sensitive, accessible, and high quality. They should offer a variety of options and excellent customer service. Key elements include institutional purpose, decision-making process, curricular design, adjunct faculty, marketing, and promotional materials. (SK)

  15. Experimental studies of W-band accelerator structures at high field

    NASA Astrophysics Data System (ADS)

    Hill, Marc Edward

    2001-06-01

    A high-gradient electron accelerator is desired for high- energy physics research, where frequency scalings of breakdown and trapping of itinerant beamline particles dictates operation of the accelerator at short wavelengths. The first results of design and test of a high-gradient mm-wave linac with an operating frequency at 91.392 GHz (W-band) are presented. A novel approach to particle acceleration is presented employing a planar, dielectric lined waveguide used for particle acceleration. The traveling wave fields in the planar dielectric accelerator (PDA) are analyzed for an idealized structure, along with a circuit equivalent model used for understanding the structure as a microwave circuit. Along with the W-band accelerator structures, other components designed and tested are high power rf windows, high power attenuators, and a high power squeeze-type phase shifter. The design of the accelerator and its components where eased with the aide of numerical simulations using a finite-difference electromagnetic field solver. Manufacturing considerations of the small, delicate mm-wave components and the steps taken to reach a robust fabrication process are detailed. These devices were characterized under low power using a two-port vector network analyzer to verify tune and match, including measurements of the structures' fields using a bead-pull. The measurements are compared with theory throughout. Addition studies of the W-band structures were performed under high power utilizing a 11.424 GHz electron linac as a current source. Test results include W-band power levels of 200 kW, corresponding to fields in the PDA of over 20 MV/m, higher than any collider. Also presented are the first measurements of the quadrapole component of the monopole accelerating field.

  16. 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.

  17. 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.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    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, 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 [1] and energy of the Nova Petawatt laser [2]. 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.

  20. Electron acceleration by femtosecond laser interaction with micro-structured plasmas

    NASA Astrophysics Data System (ADS)

    Goers, Andy James

    Laser-driven accelerators are a promising and compact alternative to RF accelerator technology for generating relativistic electron bunches for medical, scientific, and security applications. This dissertation presents three experiments using structured plasmas designed to advance the state of the art in laser-based electron accelerators, with the goal of reducing the energy of the drive laser pulse and enabling higher repetition rate operation with current laser technology. First, electron acceleration by intense femtosecond laser pulses in He-like nitrogen plasma waveguides is demonstrated. Second, significant progress toward a proof of concept realization of quasi-phasematched direct acceleration (QPM-DLA) is presented. Finally, a laser wakefield accelerator at very high plasma density is studied, enabling relativistic electron beam generation with ˜10 mJ pulse energies. Major results from these experiments include: • Acceleration of electrons up to 120 MeV from an ionization injected wakefield accelerator driven in a 1.5 mm long He-like nitrogen plasma waveguide • Guiding of an intense, quasi-radially polarized femtosecond laser pulse in a 1 cm plasma waveguide. This pulse provides a strong drive field for the QPM-DLA concept. • Wakefield acceleration of electrons up to ˜10 MeV with sub-terawatt, ˜10 mJ pulses interacting with a thin (˜200 mum), high density (>1020 cm-3) plasma. • Observation of an intense, coherent, broadband wave breaking radiation flash from a high plasma density laser wakefield accelerator. The flash radiates > 1% of the drive laser pulse energy in a bandwidth consistent with half-cycle (˜1 fs) emission from violent unidirectional acceleration of electron bunches from rest. These results open the way to high repetition rate (>˜kHz) laser-driven generation of relativistic electron beams with existing laser technology.

  1. Brain Structure and Development.

    ERIC Educational Resources Information Center

    Teyler, T.J.; Chiaia, N.

    1983-01-01

    Considers basic biology of brain, what is known of how it operates, and something of how it develops. Discusses properties of neurons and specialized regions of the brain in linguistic and higher order processing skills, as well as genetic and environmental influences on brain development. (CMG)

  2. On the Boundaries of the Acceleration of the Development of Intelligence.

    ERIC Educational Resources Information Center

    Kingma, Johannes; Tomic, Welko

    This paper examines the possibility of accelerating the development of intelligence when applying stringent Piagetian standards to evaluate the effects of short- and long-term intervention or instruction programs. The paper reviews previous Genevan and American research that shows that development can be accelerated by means of only a few…

  3. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. 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.

  6. Particle Acceleration: From Galaxies to Large Scale Structure

    SciTech Connect

    Biermann, Peter L.; Bisnovatyi-Kogan, Gennady; Moiseenko, Sergej

    2005-09-28

    In this brief review we discuss current efforts to understand the origin of energetic particles, focussing here on the recent work on the physics of supernova explosions. Acceleration to the highest energy may come from jets and hot spots emanating from massive black holes. If the sky remains smooth in the arrival directions of ultrahigh energy cosmic rays to the highest energies, then we need new sources, and one extreme speculation would be to invoke Lorentz Invariance Violation, with proton decay, neutron survival, and no strong photomeson interaction to higher energy. For the Galactic cosmic rays explosions of red supergiant stars and Wolf Rayet stars may provide much of the cosmic rays. This is intimately connected with the physics of their explosion, and implies that the magneto-rotational mechanism is the main one chosen by Nature. This offers a consistent picture for the X-ray fans of Cas A, and gamma ray bursts. Each of these concepts leads to clear predictions. It will be quite an achievement to prove this or any other proposal -- none is without difficulties. We do have potentially a full theory to account for cosmic rays at all energies; crucial tests will be performed with the current new instruments.

  7. High-Power Testing of 11.424-GHz Dielectric-Loaded Accelerating Structures

    NASA Astrophysics Data System (ADS)

    Gold, Steven; Gai, Wei

    2001-10-01

    Argonne National Laboratory has previously described the design, construction, and bench testing of an X-band traveling-wave accelerating structure loaded with a permittivity=20 dielectric (P. Zou et al., Rev. Sci. Instrum. 71, 2301, 2000.). We describe a new program to build a test accelerator using this structure. The accelerator will be powered by the high-power 11.424-GHz radiation from the magnicon facility at the Naval Research Laboratory ( O.A. Nezhevenko et al., Proc. PAC 2001, in press). The magnicon is expected to provide up to 30 MW from each of two WR-90 output waveguide arms in pulses of up to 1 microsecond duration, permitting tests up to a gradient of 40 MV/m. Still higher power pulses (100-500 MW) may be available at the output of an active pulse compressor driven by the magnicon ( A.L. Vikharev et al., Proc. 9th Workshop on Advanced Accelerator Concepts.).

  8. INTERNAL STRUCTURE OF PROTOCLUSTER GALAXIES: ACCELERATED STRUCTURAL EVOLUTION IN OVERDENSE ENVIRONMENTS?

    SciTech Connect

    Zirm, Andrew W.; Toft, Sune; Tanaka, Masayuki E-mail: sune@dark-cosmology.dk

    2012-01-10

    We present a high spatial resolution Hubble Space Telescope/NICMOS imaging survey in the field of a known protocluster surrounding the powerful radio galaxy MRC1138-262 at z = 2.16. Previously, we have shown that this field exhibits a substantial surface overdensity of red J-H galaxies. Here we focus on the stellar masses and galaxy effective radii in an effort to compare and contrast the properties of likely protocluster galaxies with their field counterparts and to look for correlations between galaxy structure and (projected) distance relative to the radio galaxy. We find a hint that quiescent, cluster galaxies are on average less dense than quiescent field galaxies of similar stellar mass and redshift. In fact, we find that only two (of eight) quiescent protocluster galaxies are of similar density to the majority of the massive, quiescent compact galaxies (Semi-Evolved Elephantine Dense galaxies; SEEDs) found in several field surveys. Furthermore, there is some indication that the structural Sersic n parameter is higher (n {approx} 3-4) on average for cluster galaxies compared to the field SEEDs (n {approx} 1-2). This result may imply that the accelerated galaxy evolution expected (and observed) in overdense regions also extends to structural evolution presuming that massive galaxies began as dense (low n) SEEDs and have already evolved to be more in line with local galaxies of the same stellar mass.

  9. 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.

  10. Random Walk Model for Cell-To-Cell Misalignments in Accelerator Structures

    SciTech Connect

    Stupakov, Gennady

    2000-09-08

    Due to manufacturing and construction errors, cells in accelerator structures can be misaligned relative to each other. As a consequence, the beam generates a transverse wakefield even when it passes through the structure on axis. The most important effect is the long-range transverse wakefield that deflects the bunches and causes growth of the bunch train projected emittance. In this paper, the effect of the cell-to-cell misalignments is evaluated using a random walk model that assumes that each cell is shifted by a random step relative to the previous one. The model is compared with measurements of a few accelerator structures.

  11. High Temperature μSR Experiments for Accelerator Developments

    NASA Astrophysics Data System (ADS)

    Ohmori, Chihiro; Koda, Akihiro; Miyake, Yasuhiro; Nishiyama, Kusuo; Shimomura, Koichiro; Schnase, Alexander; Ezura, Eiji; Hara, Keigo; Hasegawa, Katsushi; Nomura, Masahiro; Shimada, Taihei; Takata, Koji; Tamura, Fumihiko; Toda, Makoto; Yamamoto, Masanobu; Yoshii, Masahito

    High temperature μSR is a powerful technique to study magnetic materials. In J-PARC accelerator synchrotrons, the Rapid Cycling Synchrotron (RCS) and Main Ring (MR), a unique magnetic alloy-loaded cavity is used for the beam acceleration and much higher field gradient has been achieved. Such high field gradient cavities made a compact RCS possible by reducing the length for beam acceleration. Now, further upgrades of the J-PARC, RF cavities with higher RF voltage and less power loss in the magnetic core are needed for the MR. For the improvements of the magnetic property of magnetic alloy core, the high temperature μSR (muon Spin Rotation/Relaxation) was used to investigate the crystallization process of the material. Based on the measurement results, the test production of the large ring cores of a magnetic alloy, FT3L, was tried. The FT3L is the magnetic alloy which has two times better performance than the present one, FT3M. For the FT3L production, the magnetic annealing is needed to control the easy-magnetized axis of the crystalline. After the success of the test production, a mass production was started in the industry to replace all existing cavities in the MR. The first 5-cell FT3L cavity is assembled for the bench test before the installation in the accelerator tunnel. By the new cavities, the total RF voltage of J-PARC MR will be doubled to increase the beam power for neutrino experiment. In future, the cavities will be also used for the RCS to increase the beam power beyond 1 MW.

  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. CPU-GPU hybrid accelerating the Zuker algorithm for RNA secondary structure prediction applications

    PubMed Central

    2012-01-01

    Background Prediction of ribonucleic acid (RNA) secondary structure remains one of the most important research areas in bioinformatics. The Zuker algorithm is one of the most popular methods of free energy minimization for RNA secondary structure prediction. Thus far, few studies have been reported on the acceleration of the Zuker algorithm on general-purpose processors or on extra accelerators such as Field Programmable Gate-Array (FPGA) and Graphics Processing Units (GPU). To the best of our knowledge, no implementation combines both CPU and extra accelerators, such as GPUs, to accelerate the Zuker algorithm applications. Results In this paper, a CPU-GPU hybrid computing system that accelerates Zuker algorithm applications for RNA secondary structure prediction is proposed. The computing tasks are allocated between CPU and GPU for parallel cooperate execution. Performance differences between the CPU and the GPU in the task-allocation scheme are considered to obtain workload balance. To improve the hybrid system performance, the Zuker algorithm is optimally implemented with special methods for CPU and GPU architecture. Conclusions Speedup of 15.93× over optimized multi-core SIMD CPU implementation and performance advantage of 16% over optimized GPU implementation are shown in the experimental results. More than 14% of the sequences are executed on CPU in the hybrid system. The system combining CPU and GPU to accelerate the Zuker algorithm is proven to be promising and can be applied to other bioinformatics applications. PMID:22369626

  14. Analysis of male pheromones that accelerate female reproductive organ development.

    PubMed

    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.

  15. 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.

  16. 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.

  17. 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…

  18. Muscle mass, structural and functional investigations of senescence-accelerated mouse P8 (SAMP8)

    PubMed Central

    Guo, An Yun; Leung, Kwok Sui; Siu, Parco Ming Fai; Qin, Jiang Hui; Chow, Simon Kwoon Ho; Qin, Ling; Li, Chi Yu; Cheung, Wing Hoi

    2015-01-01

    Sarcopenia is an age-related systemic syndrome with progressive deterioration in skeletal muscle functions and loss in mass. Although the senescence-accelerated mouse P8 (SAMP8) was reported valid for muscular ageing research, there was no report on the details such as sarcopenia onset time. Therefore, this study was to investigate the change of muscle mass, structure and functions during the development of sarcopenia. Besides the average life span, muscle mass, structural and functional measurements were also studied. Male SAMP8 animals were examined at month 6, 7, 8, 9, and 10, in which the right gastrocnemius was isolated and tested for ex vivo contractile properties and fatigability while the contralateral one was harvested for muscle fiber cross-sectional area (FCSA) and typing assessments. Results showed that the peak of muscle mass appeared at month 7 and the onset of contractility decline was observed from month 8. Compared with month 8, most of the functional parameters at month 10 decreased significantly. Structurally, muscle fiber type IIA made up the largest proportion of the gastrocnemius, and the fiber size was found to peak at month 8. Based on the altered muscle mass, structural and functional outcomes, it was concluded that the onset of sarcopenia in SAMP8 animals was at month 8. SAMP8 animals at month 8 should be at pre-sarcopenia stage while month 10 at sarcopenia stage. It is confirmed that SAMP8 mouse can be used in sarcopenia research with established time line in this study. PMID:26193895

  19. Active vibration suppression through positive acceleration feedback on a building-like structure: An experimental study

    NASA Astrophysics Data System (ADS)

    Enríquez-Zárate, J.; Silva-Navarro, G.; Abundis-Fong, H. F.

    2016-05-01

    This work deals with the structural and dynamic analysis of a building-like structure consisting of a three-story building with one active vibration absorber. The base of the structure is perturbed using an electromagnetic shaker, which provides forces with a wide range of excitation frequencies, including some resonance frequencies of the structure. One beam-column of the structure is coupled with a PZT stack actuator to reduce the vibrations. The overall mechanical structure is modeled using Euler-Lagrange methodology and validated using experimental modal analysis and Fine Element Method (FEM) techniques. The active control laws are synthesized to actively attenuate the vibration system response via the PZT stack actuator, caused by excitation forces acting on the base of the structure. The control scheme is obtained using Positive Acceleration Feedback (PAF) and Multiple Positive Acceleration Feedback (MPAF) to improve the closed-loop system response. Some experimental results are included to illustrate the overall system performance.

  20. Development of the Accelerator Mass Spectrometry technology at the Comenius University in Bratislava

    NASA Astrophysics Data System (ADS)

    Povinec, Pavel P.; Masarik, Jozef; Ješkovský, Miroslav; Kaizer, Jakub; Šivo, Alexander; Breier, Robert; Pánik, Ján; Staníček, Jaroslav; Richtáriková, Marta; Zahoran, Miroslav; Zeman, Jakub

    2015-10-01

    An Accelerator Mass Spectrometry (AMS) laboratory has been established at the Centre for Nuclear and Accelerator Technologies (CENTA) at the Comenius University in Bratislava comprising of a MC-SNICS ion source, 3 MV Pelletron tandem accelerator, and an analyzer of accelerated ions. The preparation of targets for 14C and 129I AMS measurements is described in detail. The development of AMS techniques for potassium, uranium and thorium analysis in radiopure materials required for ultra-low background underground experiments is briefly mentioned.

  1. High power testing of a fused quartz-based dielectric-loaded accelerating structure.

    SciTech Connect

    Power, J. G.; Konecny, R.; Gai, W.; Yusof, Z.; Gold, S. H.; Kinkead, A.; Dolgashev, V.; Tantawi, S. G.; Jing, C.; High Energy Physics; Euclid techlabs, LLC; LET Corp.; SLAC; NRL

    2008-01-01

    We report on the most recent results from a series of high power tests being carried out on rf-driven dielectric-loaded accelerating (DLA) structures. The purpose of these tests is to determine the viability of the DLA as a traveling-wave accelerator and is a collaborative effort between Argonne National Laboratory (ANL), Naval Research Laboratory (NRL), and Stanford Linear Accelerator Center (SLAC). In this paper, we report on the recent high power tests of a fused quartz-based DLA structure that was carried out at incident powers of up to 12 MW at NRL and 37 MW at SLAC. We also report on test results of a TiN coated quartz structure, that exhibits good multipactor suppression.

  2. High Power Testing of A Fused Quartz-based Dielectric-Loaded Accelerating Structure

    SciTech Connect

    Jing, C.; Power, J.G.; Konecny, R.; Gai, W.; Yusof, Z.; Gold, S.H.; Kinkead, A.K.; Dolgashev, V.; Tantawi, S.G.; /SLAC

    2007-11-07

    We report on the most recent results from a series of high power tests being carried out on rf-driven dielectric loaded accelerating (DLA) structures. The purpose of these tests is to determine the viability of the DLA as a traveling-wave accelerator and is a collaborative effort between Argonne National Laboratory (ANL), Naval Research Laboratory (NRL), and Stanford Linear Accelerator Center (SLAC). In this paper, we report on the recent high power tests of a fused quartz-based DLA structure that was carried out at incident powers of up to 12 MW at NRL and 37 MW at SLAC. We also report on test results of a TiN coated quartz structure, that exhibits good multipactor suppression.

  3. 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.

  4. Experimental study of X-band dielectric-loaded accelerating structures

    NASA Astrophysics Data System (ADS)

    Jing, Chunguang

    A joint Argonne National Laboratory (ANL)/Naval Research Laboratory (NRL) program is under way to investigate X-band dielectric-loaded accelerating (DLA) structures, using high-power 11.424GHz radiation from the NRL Magnicon facility. As an advanced accelerator concepts, the dielectric-loaded accelerator offers the potential for a simple, inexpensive alternative to high-gradient RF linear accelerators. In this thesis, a comprehensive account of X-band DLA structure design, including theoretical calculation, numerical simulation, fabrication and testing, is presented in detail. Two types of loading dielectrics, alumina and MgxCa1-xTiO 3 (MCT), are investigated. For alumina (with dielectric constant 9.4), no RF breakdown has been observed up to 5 MW of drive power (equivalent to 8MV/m accelerating gradient) in the high power RF testing at NRL, but multipactor was observed to absorb a large fraction of the incident microwave power. Experimental results on suppression of multipactor using TiN coating on the inner surface of the dielectric are also reported. For MCT (with dielectric constant 20), although we did not observe dielectric breakdown in the structures, breakdown did occur at the ceramic joint, where the electric field is greatly enhanced (estimated to be around 100MV/m) due to the micro-scale vacuum gap. In addition, the MCT structure showed significantly less multipactor for the same level of RF field. The thesis also introduced a new design, a multilayered dielectric-loaded accelerating structure, to improve the performance over the conventional one layer DLA structure. Results of analysis for the case of a four layered DLA structure indicate a large reduction of RF power attenuation and an increase of shunt impedance for the structure. Beyond the main contents, the appendices of the thesis present two individual projects prompted by the experimental study of the dielectric-loaded accelerating structure. Appendix A shows a resonant loop technique that can

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2016-08-01

    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.

  7. 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.; 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 guidingmore » structure for the accelerating laser pulse may provide a way of compensating for the group velocity and transverse expansion effects.« less

  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. Comparisons of electron acceleration efficiency among different structures during magnetic reconnection: a Cluster multicase study

    NASA Astrophysics Data System (ADS)

    Zhou, M.; Li, T.; Deng, X.; Huang, S.; Li, H.

    2015-12-01

    Magnetic reconnection has long been believed to be an efficient engine for energetic electrons production. Four different structures have been proposed for electrons being energized: flux pileup region, density cavity located around the separatrix, magnetic island and thin current sheet. In this paper, we compare the electron acceleration efficiency among these structures based on 12 magnetotail reconnection events observed by the Cluster spacecraft in 2001-2006. We used the flux ratio between the energetic electrons (> 50 keV) and lower energy electrons (< 26 keV) to quantify the electron acceleration efficiency. We do not find any specific sequence in which electrons are accelerated within these structures, though the flux pileup region, magnetic island and thin current sheet have higher probabilities to reach the maximum efficiency among the four structures than the density cavity. However, the most efficient electron energization usually occurs outside these structures. We suggest that other structures may also play important roles in energizing electrons. Our results could provide important constraints for the further modeling of electron acceleration during magnetic reconnection.

  10. Experimental measurements of rf breakdowns and deflecting gradients in 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.

    2016-05-01

    We present an experimental study of a high gradient metallic accelerating structure at sub-THz frequencies, where we investigated the physics of rf breakdowns. Wakefields in the structure were excited by an ultrarelativistic electron beam. We present the first quantitative measurements of gradients and metal vacuum rf breakdowns in sub-THz accelerating cavities. When the beam travels off axis, a deflecting field is induced in addition to the longitudinal field. We measured the deflecting forces by observing the displacement and changes in the shape of the electron bunch. This behavior can be exploited for subfemtosecond beam diagnostics.

  11. Three-dimensional Dielectric Photonic Crystal Structures for Laser-driven Acceleration

    SciTech Connect

    Cowan, Benjamin M.; /Tech-X, Boulder /SLAC

    2007-12-14

    We present the design and simulation of a three-dimensional photonic crystal waveguide for linear laser-driven acceleration in vacuum. The structure confines a synchronous speed-of-light accelerating mode in both transverse dimensions. We report the properties of this mode, including sustainable gradient and optical-to-beam efficiency. We present a novel method for confining a particle beam using optical fields as focusing elements. This technique, combined with careful structure design, is shown to have a large dynamic aperture and minimal emittance growth, even over millions of optical wavelengths.

  12. 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.

  13. 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.

  14. Biomedical discovery acceleration, with applications to craniofacial development.

    PubMed

    Leach, Sonia M; Tipney, Hannah; Feng, Weiguo; Baumgartner, William A; Kasliwal, Priyanka; Schuyler, Ronald P; Williams, Trevor; Spritz, Richard A; Hunter, Lawrence

    2009-03-01

    The profusion of high-throughput instruments and the explosion of new results in the scientific literature, particularly in molecular biomedicine, is both a blessing and a curse to the bench researcher. Even knowledgeable and experienced scientists can benefit from computational tools that help navigate this vast and rapidly evolving terrain. In this paper, we describe a novel computational approach to this challenge, a knowledge-based system that combines reading, reasoning, and reporting methods to facilitate analysis of experimental data. Reading methods extract information from external resources, either by parsing structured data or using biomedical language processing to extract information from unstructured data, and track knowledge provenance. Reasoning methods enrich the knowledge that results from reading by, for example, noting two genes that are annotated to the same ontology term or database entry. Reasoning is also used to combine all sources into a knowledge network that represents the integration of all sorts of relationships between a pair of genes, and to calculate a combined reliability score. Reporting methods combine the knowledge network with a congruent network constructed from experimental data and visualize the combined network in a tool that facilitates the knowledge-based analysis of that data. An implementation of this approach, called the Hanalyzer, is demonstrated on a large-scale gene expression array dataset relevant to craniofacial development. The use of the tool was critical in the creation of hypotheses regarding the roles of four genes never previously characterized as involved in craniofacial development; each of these hypotheses was validated by further experimental work.

  15. Biomedical Discovery Acceleration, with Applications to Craniofacial Development

    PubMed Central

    Feng, Weiguo; Baumgartner, William A.; Kasliwal, Priyanka; Schuyler, Ronald P.; Williams, Trevor; Spritz, Richard A.; Hunter, Lawrence

    2009-01-01

    The profusion of high-throughput instruments and the explosion of new results in the scientific literature, particularly in molecular biomedicine, is both a blessing and a curse to the bench researcher. Even knowledgeable and experienced scientists can benefit from computational tools that help navigate this vast and rapidly evolving terrain. In this paper, we describe a novel computational approach to this challenge, a knowledge-based system that combines reading, reasoning, and reporting methods to facilitate analysis of experimental data. Reading methods extract information from external resources, either by parsing structured data or using biomedical language processing to extract information from unstructured data, and track knowledge provenance. Reasoning methods enrich the knowledge that results from reading by, for example, noting two genes that are annotated to the same ontology term or database entry. Reasoning is also used to combine all sources into a knowledge network that represents the integration of all sorts of relationships between a pair of genes, and to calculate a combined reliability score. Reporting methods combine the knowledge network with a congruent network constructed from experimental data and visualize the combined network in a tool that facilitates the knowledge-based analysis of that data. An implementation of this approach, called the Hanalyzer, is demonstrated on a large-scale gene expression array dataset relevant to craniofacial development. The use of the tool was critical in the creation of hypotheses regarding the roles of four genes never previously characterized as involved in craniofacial development; each of these hypotheses was validated by further experimental work. PMID:19325874

  16. Laser acceleration with open waveguides

    SciTech Connect

    Xie, Ming

    1999-03-01

    A unified framework based on solid-state open waveguides is developed to overcome all three major limitations on acceleration distance and hence on the feasibility of two classes of laser acceleration. The three limitations are due to laser diffraction, acceleration phase slippage, and damage of waveguide structure by high power laser. The two classes of laser acceleration are direct-field acceleration and ponderomotive-driven acceleration. Thus the solutions provided here encompass all mainstream approaches for laser acceleration, either in vacuum, gases or plasmas.

  17. Comparison of accelerated T1-weighted whole-brain structural-imaging protocols.

    PubMed

    Falkovskiy, Pavel; Brenner, Daniel; Feiweier, Thorsten; Kannengiesser, Stephan; Maréchal, Bénédicte; Kober, Tobias; Roche, Alexis; Thostenson, Kaely; Meuli, Reto; Reyes, Denise; Stoecker, Tony; Bernstein, Matt A; Thiran, Jean-Philippe; Krueger, Gunnar

    2016-01-01

    Imaging in neuroscience, clinical research and pharmaceutical trials often employs the 3D magnetisation-prepared rapid gradient-echo (MPRAGE) sequence to obtain structural T1-weighted images with high spatial resolution of the human brain. Typical research and clinical routine MPRAGE protocols with ~1mm isotropic resolution require data acquisition time in the range of 5-10min and often use only moderate two-fold acceleration factor for parallel imaging. Recent advances in MRI hardware and acquisition methodology promise improved leverage of the MR signal and more benign artefact properties in particular when employing increased acceleration factors in clinical routine and research. In this study, we examined four variants of a four-fold-accelerated MPRAGE protocol (2D-GRAPPA, CAIPIRINHA, CAIPIRINHA elliptical, and segmented MPRAGE) and compared clinical readings, basic image quality metrics (SNR, CNR), and automated brain tissue segmentation for morphological assessments of brain structures. The results were benchmarked against a widely-used two-fold-accelerated 3T ADNI MPRAGE protocol that served as reference in this study. 22 healthy subjects (age=20-44yrs.) were imaged with all MPRAGE variants in a single session. An experienced reader rated all images of clinically useful image quality. CAIPIRINHA MPRAGE scans were perceived on average to be of identical value for reading as the reference ADNI-2 protocol. SNR and CNR measurements exhibited the theoretically expected performance at the four-fold acceleration. The results of this study demonstrate that the four-fold accelerated protocols introduce systematic biases in the segmentation results of some brain structures compared to the reference ADNI-2 protocol. Furthermore, results suggest that the increased noise levels in the accelerated protocols play an important role in introducing these biases, at least under the present study conditions. PMID:26297848

  18. Development of high intensity linear accelerator for heavy ion inertial fusion driver

    NASA Astrophysics Data System (ADS)

    Lu, Liang; Hattori, Toshiyuki; Hayashizaki, Noriyosu; Ishibashi, Takuya; Okamura, Masahiro; Kashiwagi, Hirotsugu; Takeuchi, Takeshi; Zhao, Hongwei; He, Yuan

    2013-11-01

    In order to verify the direct plasma injection scheme (DPIS), an acceleration test was carried out in 2001 using a radio frequency quadrupole (RFQ) heavy ion linear accelerator (linac) and a CO2-laser ion source (LIS) (Okamura et al., 2002) [1]. The accelerated carbon beam was observed successfully and the obtained current was 9.22 mA for C4+. To confirm the capability of the DPIS, we succeeded in accelerating 60 mA carbon ions with the DPIS in 2004 (Okamura et al., 2004; Kashiwagi and Hattori, 2004) [2,3]. We have studied a multi-beam type RFQ with an interdigital-H (IH) cavity that has a power-efficient structure in the low energy region. We designed and manufactured a two-beam type RFQ linac as a prototype for the multi-beam type linac; the beam acceleration test of carbon beams showed that it successfully accelerated from 5 keV/u up to 60 keV/u with an output current of 108 mA (2×54 mA/channel) (Ishibashi et al., 2011) [4]. We believe that the acceleration techniques of DPIS and the multi-beam type IH-RFQ linac are technical breakthroughs for heavy-ion inertial confinement fusion (HIF). The conceptual design of the RF linac with these techniques for HIF is studied. New accelerator-systems using these techniques for the HIF basic experiment are being designed to accelerate 400 mA carbon ions using four-beam type IH-RFQ linacs with DPIS. A model with a four-beam acceleration cavity was designed and manufactured to establish the proof of principle (PoP) of the accelerator.

  19. Development of accelerator mass spectrometer based on a compact cyclotron

    NASA Astrophysics Data System (ADS)

    Kim, J.-W.; Kim, D.-G.

    2011-07-01

    A small cyclotron has been designed for accelerator mass spectrometry, and the injection beam line is constructed as part of prototyping. Mass resolution of the cyclotron is estimated to be around 4000. The design of the cyclotron was performed with orbit-tracking computations using 3D magnetic and electric fields, and beam optics of the injection line was calculated using the codes such as IGUN and TRANSPORT. The radial injection scheme is chosen to place a beam on equilibrium orbit of the cyclotron. The injection line includes an ion source, Einzel lens, rf buncher, 90° dipole magnet, and quadrupole triplet magnet. A carbon beam was extracted from the front part of the injection line. An rf cavity system for the cyclotron was built and tested. A multi channel plates (MCP) detector to measure low-current ion beams was also tested. Design considerations are given to analyzing a few different radioisotopes in form of positive ions as well as negative ions.

  20. Accelerating Full Configuration Interaction Calculations for Nuclear Structure

    SciTech Connect

    Yang, Chao; Sternberg, Philip; Maris, Pieter; Ng, Esmond; Sosonkina, Masha; Le, Hung Viet; Vary, James; Yang, Chao

    2008-04-14

    One of the emerging computational approaches in nuclear physics is the full configuration interaction (FCI) method for solving the many-body nuclear Hamiltonian in a sufficiently large single-particle basis space to obtain exact answers - either directly or by extrapolation. The lowest eigenvalues and correspondingeigenvectors for very large, sparse and unstructured nuclear Hamiltonian matrices are obtained and used to evaluate additional experimental quantities. These matrices pose a significant challenge to the design and implementation of efficient and scalable algorithms for obtaining solutions on massively parallel computer systems. In this paper, we describe the computational strategies employed in a state-of-the-art FCI code MFDn (Many Fermion Dynamics - nuclear) as well as techniques we recently developed to enhance the computational efficiency of MFDn. We will demonstrate the current capability of MFDn and report the latest performance improvement we have achieved. We will also outline our future research directions.

  1. Observation of wakefields in a beam-driven photonic band gap accelerating structure.

    SciTech Connect

    Conde, M.; Yusof, Z.; Power, J. G.; Jing, C.; Gao, F.; Antipov, S.; Xu, P.; Zheng, S.; Chen, H.; Tang, C.; Gai, W.; High Energy Physics; Euclid Techlabs LLC; Tsinghua Univ.

    2009-12-01

    Wakefield excitation has been experimentally studied in a three-cell X-band standing wave photonic band gap (PBG) accelerating structure. Major monopole (TM{sub 01}- and TM{sub 02}-like) and dipole (TM{sub 11}- and TM{sub 12}-like) modes were identified and characterized by precisely controlling the position of beam injection. The quality factor Q of the dipole modes was measured to be {approx}10 times smaller than that of the accelerating mode. A charge sweep, up to 80 nC, has been performed, equivalent to {approx} 30 MV/m accelerating field on axis. A variable delay low charge witness bunch following a high charge drive bunch was used to calibrate the gradient in the PBG structure by measuring its maximum energy gain and loss. Experimental results agree well with numerical simulations.

  2. 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

  3. 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.; Power, J. G.; Conde, M.; Wisniewski, E.; Liu, W.; Qiu, J.; Ha, G.; Dolgashev, V.; et al

    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

  4. 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

    2016-02-01

    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. PMID:26894715

  5. 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.

  6. Theory of Generation of Alfvenic Non-Propagating Electromagnetic Plasma Structures and Acceleration of Charged Particles in Cosmic Plasmas

    NASA Astrophysics Data System (ADS)

    Song, Yan; Lysak, Robert

    2015-04-01

    In Earth's auroral acceleration regions, the nonlinear interaction of incident and reflected Alfven wave packets can collectively create non-propagating electromagnetic plasma structures, such as the Transverse Alfvenic Double Layer (TA-DL) and Charge Hole (TA-CH). These structures, such as TA-DL, encompass localized strong electrostatic electric fields, nested in low density cavities and surrounded by a local dynamo. Such structures constitute powerful high energy particle accelerators causing auroral particle acceleration and creating both Alfvenic and quasi-static discrete auroras. Similar electromagnetic plasma structures should also be generated by Alfvenic interaction in other inhomogenous cosmic plasma regions, and would constitute effective high energy particle accelerators.

  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. NASA - 77M prototype hall thruster built under the High Voltage Hall accelerator development project

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA - 77M prototype hall thruster built under the High Voltage Hall accelerator development project funded by the Science Mission Directorate ; potential use is propulsion for deep space science missions

  9. 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.

  10. Temporal and Spatial Characteristics of Acceleration Structures in the Auroral Return Current Region

    NASA Astrophysics Data System (ADS)

    Marklund, G. T.; Karlsson, T.; Figueiredo, S.; Johansson, T.; Buchert, S.

    2003-12-01

    Temporal and spatial characteristics of high-altitude auroral electric fields, and, in particular, those which are related to quasi-static auroral electric potential structures, are discussed using Cluster multi-point observations from auroral field line crossings at geocentric distances of about 5 RE. Intense and narrow-structured diverging electric fields, associated with upward accelerated electrons, being fingerprints of quasi-static acceleration structures in the auroral return current region, appear more frequently at these altitudes than their counterpart, converging electric fields, on auroral field lines, for reasons not yet understood. The time needed for evacuating ionospheric electrons at the ionospheric end of the return current flux tube, which depend on the field-aligned current density, represent one characteristic time scale for the accelerating electric fields. We present results from four Cluster encounters with such acceleration structures and how these and their associated field-aligned current and electron distributions, evolve on the different time scales given by different inter-spacecraft separation distances.

  11. Alignment tolerance of accelerating structures and corrections for future linear colliders

    SciTech Connect

    Kubo, K.; Adolphsen, C.; Bane, K.L.F.; Raubenheimer, T.O.; Thompson, K.A.

    1995-06-01

    The alignment tolerance of accelerating structures is estimated by tracking simulations. Both single-bunch and multi-bunch effects are taken into account. Correction schemes for controlling the single and multi-bunch emittance growth in the case of large misalignment are also tested by simulations.

  12. 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.

  13. The C-Band accelerating structures for SPARC photoinjector energy upgrade

    NASA Astrophysics Data System (ADS)

    Alesini, D.; Boni, R.; Di Pirro, G.; Di Raddo, R.; Ferrario, M.; Gallo, A.; Lollo, V.; Marcellini, F.; Palumbo, L.; Spizzo, V.; Mostacci, A.; Campogiani, G.; Persichelli, S.; Enomoto, A.; Higo, T.; Kakihara, K.; Kamitani, T.; Matsumoto, S.; Sugimura, T.; Yokoyama, K.; Verdú-Andrés, S.

    2013-05-01

    The use of C-Band structures for electron acceleration and production of high quality beams has been proposed and adopted in several linac projects all over the world. The two main projects that adopted such type of structures are the Japanese Free Electron Laser (FEL) project in Spring-8 and the SwissFEL project at Paul Scherrer Institute (PSI). Also the energy upgrade of the SPARC photo-injector at LNF-INFN (Italy) from 150 to more than 240 MeV will be done by replacing a low gradient S-Band accelerating structure with two C-band structures. The structures are Traveling Wave (TW) and Constant Impedance (CI), have symmetric axial input couplers and have been optimized to work with a SLED RF input pulse. The paper presents the design criteria of the structures, the realization procedure and the low and high power RF test results on a prototype. The high power tests have been carried out by the Frascati INFN Laboratories in close collaboration with the Japanese Laboratory KEK. Experimental results confirmed the feasibility of the operation of the prototype at 50 MV/m with about 10-6 breakdowns per pulse per meter. Such high gradients have not been reached before in C-Band systems and demonstrated the possibility to use C-band accelerators, if needed, at such high field level. The results of the internal inspection of the structure after the high power test are also presented.

  14. Development of a 15 T $Nb_3Sn$ Accelerator Dipole Demonstrator at Fermilab

    SciTech Connect

    Novitski, I.; Andreev, N.; Barzi, E.; Carmichael, J.; Kashikhin, V. V.; Turrion, D.; Yu, M.; Zlobin, A. V.

    2015-01-01

    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 $Nb_3Sn$ 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.

  15. Development of a 15 T $Nb_3Sn$ Accelerator Dipole Demonstrator at Fermilab

    SciTech Connect

    Novitski, I.; Andreev, N.; Barzi, E.; Carmichael, J.; Kashikhin, V. V.; Turrion, D.; Yu, M.; Zlobin, A. V.

    2016-01-01

    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 $Nb_3Sn$ 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.

  16. 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.

  17. 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

  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. Summary report : working group 5 on 'electron beam-driven plasma and structure based acceleration concepts'.

    SciTech Connect

    Conde, M. E.; Katsouleas, T.

    2000-10-19

    The talks presented and the work performed on electron beam-driven accelerators in plasmas and structures are summarized. Highlights of the working group include new experimental results from the E-157 Plasma Wakefield Experiment, the E-150 Plasma Lens Experiment and the Argonne Dielectric Structure Wakefield experiments. The presentations inspired discussion and analysis of three working topics: electron hose instability, ion channel lasers and the plasma afterburner.

  20. Some problems on rf breakdown in room temperature accelerator structure, a possible criterion

    SciTech Connect

    Wang, J.W.

    1986-04-01

    The discussion is confined to high gradient, room-temperature accelerators which have clean well-finished cavity surfaces and good vacuum conditions. Breakdown-initiating mechanisms due to ''cold'' field electron emission occurring at isolated sites on broad-area cavity surfaces, where the field is enhanced, are described. The influences of an alternating field and transition time tunneling are taken into account. The thermal instability resulting in vacuum voltage breakdown is hypothesized to derive a new criterion for room-temperature accelerator structure. 18 refs., 5 figs. (DWL)

  1. Construction and testing of an 11.4 GHz dielectric structure based travelling wave accelerator.

    SciTech Connect

    Gai, W.; Konecny, R.; Wong, T.; Zou, P.

    1999-03-26

    One major challenge in constructing a dielectric loaded traveling wave accelerator powered by an external rf power source is the difficulty in achieving efficient coupling. In this paper, we report that we have achieved high efficiency broadband coupling by using a combination of a tapered dielectric section and a carefully adjusted coupling slot. We are currently constructing an 11.4 GHz accelerator structure loaded with a permitivity=20 dielectric. Bench testing has demonstrated a coupling efficiency in excess of 95% with bandwidth of 600 MHz. The final setup will be tested at high power at SLAC using an X-band klystron rf source.

  2. Construction and testing of an 11.4 GHz dielectric structure based traveling wave accelerator

    NASA Astrophysics Data System (ADS)

    Zou, P.; Gai, W.; Konecny, R.; Sun, X.; Wong, T.; Kanareykin, A.

    2000-06-01

    We report on the design, numerical modeling, and experimental testing of a cylindrical dielectric loaded traveling wave structure for charged particle beam acceleration. This type of structure has similar accelerating properties to disk-loaded metal slow wave structures but with some distinct advantages in terms of simplicity of fabrication and suppression of parasitic wakefield effects. Efficient coupling of external rf power to the cylindrical dielectric waveguide is a technical challenge, particularly with structures of very high dielectric constant ɛ. We have designed and constructed an X-band structure loaded with a permittivity ɛ=20 dielectric to be powered by an external rf power source. We have attained high efficiency broadband rf coupling by using a combination of a tapered dielectric end section and a carefully adjusted coupling slot. Bench testing using a network analyzer has demonstrated a power coupling efficiency in excess of 95% with bandwidth of 30 MHz, thus providing a necessary basis for construction of an accelerator using this device. We have also simulated the parameters of this structure using a finite difference time domain electromagnetic solver. Within the limits of the approximations used, the results are in reasonable agreement with the bench measurements.

  3. 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

  4. 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

    2016-01-01

    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

  5. 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. PMID:24605482

  6. The influence of acceleration forces on dendritic growth and grain structure

    NASA Technical Reports Server (NTRS)

    Johnston, M. H.; Parr, R. A.

    1982-01-01

    The results of experiments on the tin-15 wt pct lead system are presented, showing the effects on microstructure of solidification in the presence of acceleration forces from 0.0001 to 5 g for three cooling rates. An increase in the acceleration level is shown to drive fluid flow and cause dendrite remelting, fragmentation, and macrosegregation. The cooling rate impacts the final structure through its control of dendrite arm spacings and permeability to fluid flow. At the low (0.0001 g) acceleration, dendrite arm spacings deviated from the predicted relationship to cooling rate. An explanation for this anomaly is given which considers the temperature and concentration gradients in the low-gravity environment.

  7. Accelerating NASA GN&C Flight Software Development

    NASA Technical Reports Server (NTRS)

    Tamblyn, Scott; Henry, Joel; Rapp, John

    2010-01-01

    When the guidance, navigation, and control (GN&C) system for the Orion crew vehicle undergoes Critical Design Review (CDR), more than 90% of the flight software will already be developed - a first for NASA on a project of this scope and complexity. This achievement is due in large part to a new development approach using Model-Based Design.

  8. 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.

  9. 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+.

  10. 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.

  11. 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.

  12. EuCARD 2010: European coordination of accelerator research and development

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2010-09-01

    Accelerators are basic tools of the experimental physics of elementary particles, nuclear physics, light sources of the fourth generation. They are also used in myriad other applications in research, industry and medicine. For example, there are intensely developed transmutation techniques for nuclear waste from nuclear power and atomic industries. The European Union invests in the development of accelerator infrastructures inside the framework programs to build the European Research Area. The aim is to build new accelerator research infrastructures, develop the existing ones, and generally make the infrastructures more available to competent users. The paper summarizes the first year of activities of the EU FP7 Project Capacities EuCARD -European Coordination of Accelerator R&D. EuCARD is a common venture of 37 European Accelerator Laboratories, Institutes, Universities and Industrial Partners involved in accelerator sciences and technologies. The project, initiated by ESGARD, is an Integrating Activity co-funded by the European Commission under Framework Program 7 - Capacities for a duration of four years, starting April 1st, 2009. Several teams from this country participate actively in this project. The contribution from Polish research teams concerns: photonic and electronic measurement - control systems, RF-gun co-design, thin-film superconducting technology, superconducting transport infrastructures, photon and particle beam measurements and control.

  13. 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.

  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. 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.

  16. 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.)

  17. 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}

  18. 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.

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

    PubMed

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

    2012-09-01

    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 p27(Kip1) 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. PMID

  1. 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

  2. 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.

  3. 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.

  4. 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.

  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. 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.

  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. Accelerate social development to promote the advancement of society.

    PubMed

    Hao, J

    1995-02-01

    The statement of the vice minister of the Chinese State Planning Commission emphasized the achievements made by the government in improving the quality of life of the Chinese people, protecting the environment, controlling population growth, improving health and employment, improving public and social security, and promoting national solidarity. The Chinese government will look forward to sharing the Chinese experiences with social development at the forthcoming UN World Summit on Social Development in March, 1995. Since 1980 a national program for economic development has been in force. Since 1949 and the founding of the People's Republic and particularly since 1978, many advances have been made. The Chinese government has been able to provide adequate food and clothing for a population comprising 22% of the world's population living on 7% of the world's land. Not only have basic living standards been met, but per capital disposable income has increased. Ownership of durable consumer goods has increased to the level of moderately developed countries. Radio messages reach about 80% of the population, and television reaches about 83% of the population. Family planning programs have promoted a balance among population with ecology and socioeconomic development. The rate of natural increase has declined from 25.83 in 1970 to 11.45 in 1993. The crude birth rate for the same period declined from 33.43 to 18.09. The crude death rate has remained at about 6-7 per 1000 population. The total fertility rate has been reduced to 2.0. Life expectancy has increased from 65 years to 70 years. Illiteracy among the population 15 years and older has greater improved; the illiteracy rate among youth and adults was 7% in 1993. Environmental policies have brought industrial pollution under strict control. Sewage treatment plants have been built. Natural gas and centralized heating have been promoted. Sound agricultural practices have been promoted. Reforestation efforts have resulted

  9. Structural Limits on Organizational Development

    ERIC Educational Resources Information Center

    Rice, George H., Jr.

    1977-01-01

    Organizational development practitioners tend to assume that all workplaces are pretty much alike, and that emotional health in all job situations can be described in approximately the same way. They have failed to recognize the sociological and structural/functional limitations of the workplace. (Author/JG)

  10. 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…

  11. 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.

  12. One-Dimensional Electric Field Structure of an Outer Gap Accelerator

    NASA Astrophysics Data System (ADS)

    Chen, Shi-Bo; Zhang, Li

    2006-10-01

    We re-study the one-dimensional electric field structure of an outer gap accelerator by considering the physical limit of trans-field height. Inside the outer gap, the charge depletion creates a large electric field along the magnetic field lines. Electrons and/or positrons are accelerated to ultra-relativistic energies by this longitudinal electric field, and then radiate γ-ray photons by curvature radiation. The collision of these γ-rays and ambient x-ray photons further produce radiating particles, resulting in a stationary gap. We solve the structure of this longitudinal electric field together with the distributions of electrons and positrons and γ-ray photons for an aligned rotator. Our results indicate that the outer gap can extend to the light cylinder using reasonable parameters.

  13. BEAM ACCELERATION BY A MULTICELL RF CAVITY STRUCTURE PROPOSED FOR AN IMPROVED YIELD IN HYDROFORMING

    SciTech Connect

    Kang, Yoon W; Shin, Ki; Fathy, A. E.; Holmes, Jeffrey A

    2012-01-01

    We study the accelerating properties of a new multicell cavity structure with irises forming a rectangular aperture between the cavity cells. We are interested in this structure because, from a mechanical point of view, it may be possible to manufacture with high quality using a hydroforming process. RF analysis shows that the rectangular iris shape provides some asymmetric transverse focusing per half RF period, particularly for low beam energies. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing could be increased. Here we present studies of the acceleration and transport properties of these cavities by tracking particles using the ORBIT Code through time-dependent 3D cavity fields taken from CST MWS.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

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

    PubMed

    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

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

    DOE PAGES

    Clayton, C. E.; Adli, E.; Allen, J.; An, W.; Clarke, C. I.; Corde, S.; Frederico, J.; Gessner, S.; Green, S. Z.; Hogan, M. J.; et al

    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

  1. 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

  2. GPU-accelerated analysis and visualization of large structures solved by molecular dynamics flexible fitting.

    PubMed

    Stone, John E; McGreevy, Ryan; Isralewitz, Barry; Schulten, Klaus

    2014-01-01

    Hybrid structure fitting methods combine data from cryo-electron microscopy and X-ray crystallography with molecular dynamics simulations for the determination of all-atom structures of large biomolecular complexes. Evaluating the quality-of-fit obtained from hybrid fitting is computationally demanding, particularly in the context of a multiplicity of structural conformations that must be evaluated. Existing tools for quality-of-fit analysis and visualization have previously targeted small structures and are too slow to be used interactively for large biomolecular complexes of particular interest today such as viruses or for long molecular dynamics trajectories as they arise in protein folding. We present new data-parallel and GPU-accelerated algorithms for rapid interactive computation of quality-of-fit metrics linking all-atom structures and molecular dynamics trajectories to experimentally-determined density maps obtained from cryo-electron microscopy or X-ray crystallography. We evaluate the performance and accuracy of the new quality-of-fit analysis algorithms vis-à-vis existing tools, examine algorithm performance on GPU-accelerated desktop workstations and supercomputers, and describe new visualization techniques for results of hybrid structure fitting methods. PMID:25340325

  3. GPU-accelerated analysis and visualization of large structures solved by molecular dynamics flexible fitting.

    PubMed

    Stone, John E; McGreevy, Ryan; Isralewitz, Barry; Schulten, Klaus

    2014-01-01

    Hybrid structure fitting methods combine data from cryo-electron microscopy and X-ray crystallography with molecular dynamics simulations for the determination of all-atom structures of large biomolecular complexes. Evaluating the quality-of-fit obtained from hybrid fitting is computationally demanding, particularly in the context of a multiplicity of structural conformations that must be evaluated. Existing tools for quality-of-fit analysis and visualization have previously targeted small structures and are too slow to be used interactively for large biomolecular complexes of particular interest today such as viruses or for long molecular dynamics trajectories as they arise in protein folding. We present new data-parallel and GPU-accelerated algorithms for rapid interactive computation of quality-of-fit metrics linking all-atom structures and molecular dynamics trajectories to experimentally-determined density maps obtained from cryo-electron microscopy or X-ray crystallography. We evaluate the performance and accuracy of the new quality-of-fit analysis algorithms vis-à-vis existing tools, examine algorithm performance on GPU-accelerated desktop workstations and supercomputers, and describe new visualization techniques for results of hybrid structure fitting methods.

  4. Studies of beam induced dipole-mode signals in accelerating structures at the SLC

    SciTech Connect

    Seidel, M.

    1997-06-01

    Beam emittance dilution by self induced transverse fields (wakefields) in accelerating structures is a key problem in linear accelerators. To minimize the wakefield effects the beam trajectory must be precisely centered within the structures. An efficient way to achieve this is to detect beam induced microwave signals in the lowest dipole mode band and to steer the beam by minimizing these signals. This paper briefly covers some experiences from SLC S-band structures, but mainly concentrates on results of a wakefield instrumentation scheme applied to a NLC prototype X-band structure and tested with beam in the SLC linac. A beam based in-situ structure straightness measurement is shown as well as results of beam steering experiments based on phase and amplitude detection of two separated modes in the structure. After centering the beam the reduction of the wakefield was demonstrated independently by probing it with a test bunch that is deflected by the residual wakefield at a short distance behind the drive bunch.

  5. 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.

  6. Collaborative workbench for cyberinfrastructure to accelerate science algorithm development

    NASA Astrophysics Data System (ADS)

    Ramachandran, R.; Maskey, M.; Kuo, K.; Lynnes, C.

    2013-12-01

    There are significant untapped resources for information and knowledge creation within the Earth Science community in the form of data, algorithms, services, analysis workflows or scripts, and the related knowledge about these resources. Despite the huge growth in social networking and collaboration platforms, these resources often reside on an investigator's workstation or laboratory and are rarely shared. A major reason for this is that there are very few scientific collaboration platforms, and those that exist typically require the use of a new set of analysis tools and paradigms to leverage the shared infrastructure. As a result, adoption of these collaborative platforms for science research is inhibited by the high cost to an individual scientist of switching from his or her own familiar environment and set of tools to a new environment and tool set. This presentation will describe an ongoing project developing an Earth Science Collaborative Workbench (CWB). The CWB approach will eliminate this barrier by augmenting a scientist's current research environment and tool set to allow him or her to easily share diverse data and algorithms. The CWB will leverage evolving technologies such as commodity computing and social networking to design an architecture for scalable collaboration that will support the emerging vision of an Earth Science Collaboratory. The CWB is being implemented on the robust and open source Eclipse framework and will be compatible with widely used scientific analysis tools such as IDL. The myScience Catalog built into CWB will capture and track metadata and provenance about data and algorithms for the researchers in a non-intrusive manner with minimal overhead. Seamless interfaces to multiple Cloud services will support sharing algorithms, data, and analysis results, as well as access to storage and computer resources. A Community Catalog will track the use of shared science artifacts and manage collaborations among researchers.

  7. Effect of the accelerating growth of communications networks on their structure.

    PubMed

    Dorogovtsev, S N; Mendes, J F

    2001-02-01

    Motivated by data on the evolution of the Internet and World Wide Web we consider scenarios of self-organization of nonlinearly growing networks into free-scale structures. We find that the accelerating growth of networks establishes their structure. For growing networks with preferential linking and increasing density of links, two scenarios are possible. In one of them, the value of the exponent gamma of the distribution of the number of incoming links is between 3/2 and 2. In the other scenario, gamma>2 and the distribution is necessarily nonstationary.

  8. X-Band klystron development at the Stanford Linear Accelerator Center

    SciTech Connect

    Sprehn, D.W.

    2000-03-24

    X-band klystrons capable of 75 MW and utilizing either solenoidal or Periodic Permanent Magnet (PPM) focusing are undergoing design, fabrication and testing at the Stanford Linear Accelerator Center (SLAC). The klystron development is part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). SLAC has completed a solenoidal-focused X-band klystron development effort to study the design and operation of tubes with beam microperveances of 1.2. As of early 2000, nine 1.2{micro}K klystrons have been tested to 50 MW at 1.5{micro}s. The first 50 MW PPM klystron, constructed in 1996, was designed with a 0.6 {micro}K beam at 465 kV and uses a 5-cell traveling-wave output structure. Recent testing of this tube at wider pulsewidths has reached 50 MW at 55% efficiency, 2.4{micro}s and 60 Hz. A 75 MW PPM klystron prototype was constructed in 1998 and has reached the NLC design target of 75 MW at 1.5 {micro}s. A new 75 MW PPM klystron design, which is aimed at reducing the cost and increasing the reliability of multi-megawatt PPM klystrons, is under investigation. The tube is scheduled for testing during early 2001.

  9. X-band klystron development at the Stanford Linear Accelerator Center

    NASA Astrophysics Data System (ADS)

    Sprehn, Daryl; Caryotakis, George; Jongewaard, Erik N.; Phillips, Robert M.; Vlieks, A.

    2000-07-01

    X-band klystrons capable of 75 MW and utilizing either solenoidal or Periodic Permanent Magnet (PPM) focusing are undergoing design, fabrication and testing at the Stanford Linear Accelerator Center (SLAC). The klystron development is part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). SLAC has completed a solenoidal-focused X-band klystron development effort to study the design and operation of tubes with beam microperveances of 1.2. As of early 2000, nine 1.2 (mu) K klystrons have been tested to 50 MW at 1.5 microsecond(s) . The first 50 MW PPM klystron, constructed in 1996, was designed with a 0.6 (mu) K beam at 465 kV and uses a 5-cell traveling-wave output structure. Recent testing of this tube at wider pulsewidths has reached 50 MW at 55% efficiency, 2.4 microsecond(s) and 60 Hz. A 75 MW PPM klystron prototype was constructed in 1998 and has reached the NLC design target of 75 MW at 1.5 microsecond(s) . A new 75 MW PPM klystron design, which is aimed at reducing the cost and increasing the reliability of multi- megawatt PPM klystrons, is under investigation. The tube is scheduled for testing during early 2001.

  10. 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.

  11. Development of and flight results from the Space Acceleration Measurement System (SAMS)

    NASA Technical Reports Server (NTRS)

    Delombard, Richard; Finley, Brian D.; Baugher, Charles R.

    1992-01-01

    Described here is the development of and the flight results from the Space Acceleration Measurement System (SAMS) flight units used in the Orbiter middeck, Spacelab module, and the Orbitercargo bay. The SAMS units are general purpose microgravity accelerometers designed to support a variety of science experiments with microgravity acceleration measurements. A total of six flight units have been fabricated; four for use in the Orbiter middeck and Spacelab module, and two for use in the Orbiter cargo bay. The design of the units is briefly described. The initial two flights of SAMS units on STS-40 (June 1991) and STS-43 (August 1991) resulted in 371 megabytes and 2.6 gigabytes of data respectively. Analytical techniques developed to examine this quantity of acceleration data are described and sample plots of analyzed data are illustrated. Future missions for the SAMS units are listed.

  12. 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.

  13. New developments in personal computer software for accelerator simulation and analysis

    NASA Astrophysics Data System (ADS)

    Gillespie, George H.; Orthel, John L.

    1993-09-01

    The increasing power of personal computers is offering accelerator designers new options for meeting their computational requirements. Standalone and highly portable machines provide accelerator scientists with different approaches to solving problems traditionally relegated to centralized mainframe, mini-computer or networked workstation environments. Advances in user interfaces, which have provided enhanced productivity for many business and technical applications, are now being implemented for accelerator design and analysis codes. We have developed new software packages for the Macintosh personal computer platform in this vein and discuss two of them here. For use with existing FORTRAN design and analysis codes, a unique graphical user interface (GUI) has been developed. The second package is the Numerical Electrodynamics Laboratory (NEDlab), a new two-dimensional (cylindrical or Cartesian) particle and field simulation program.

  14. 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…

  15. 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.

  16. Vibration absorption in a building like structure by means of piezoelectric patches and positive acceleration feedback

    NASA Astrophysics Data System (ADS)

    Rios-Gutierrez, Max A.; Silva-Navarro, Gerardo

    2010-04-01

    This paper is about mechanical vibration suppression in a three story building like structure. The experimental platform is a laboratory prototype made of aluminum alloy with bolted joints and an elctromagnetic shaker used as a disturbance source. This prototype can be used as a representation of a civil structure as well as an industrial machinery element. This structure is modeled and validated by the application of finite element methods and experimental modal analysis. The system response is controlled by a piezoelectric actuator, properly located on the structure, and with the synthesis of a feedback control law based on the well-known positive acceleration feedback control scheme. Some numerical simulations and experiments results are performed to illustrate the overall system performance in presence of several types of excitation.

  17. 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.

  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. Optimizing the science of drug development: opportunities for better candidate selection and accelerated evaluation in humans.

    PubMed

    Lesko, L J; Rowland, M; Peck, C C; Blaschke, T F

    2000-08-01

    Two international meetings were convened in 1998 to review the current science of drug development and the potential opportunities to optimize the evaluation of new drugs in humans. This report represents a synopsis of these meetings, and focuses on the current state of knowledge pertaining to drug development, future scientific and technical needs, and the relative merits of various strategies intended to accelerate the clinical development of drugs. PMID:10934664

  20. 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)

  1. Future Development Of The Flerov Laboratory Accelerator Complex (Project DRIBs-III)

    NASA Astrophysics Data System (ADS)

    Gulbekian, G. G.; Dmitriev, S. N.; Itkis, M. G.; Oganessian, Yu. Ts.; Popeko, A. G.

    2010-04-01

    Future development of the FLNR accelerator complex (project DRIBs-III) includes modernization of existing cyclotrons, construction of a new experimental hall, creation of a new high current cyclotron and of next generation experimental set-ups. Realization of the project is planned for 2010-2016.

  2. 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...

  3. 76 FR 50224 - Medicare Program; Accountable Care Organization Accelerated Development Learning Sessions; Center...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... Accelerated Development Learning Sessions; Center for Medicare and Medicaid Innovation, September 15th and... Registration: Registration for the second ADLS will remain open until capacity has been reached for the... Medicare and Medicaid Innovation (Innovation Center) for the purpose of examining new ways of...

  4. 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…

  5. Development of a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy.

    PubMed

    Kreiner, A J; Castell, W; Di Paolo, H; Baldo, M; Bergueiro, J; Burlon, A A; Cartelli, D; Vento, V Thatar; Kesque, J M; Erhardt, J; Ilardo, J C; Valda, A A; Debray, M E; Somacal, H R; Sandin, J C Suarez; Igarzabal, M; Huck, H; Estrada, L; Repetto, M; Obligado, M; Padulo, J; Minsky, D M; Herrera, M; Gonzalez, S J; Capoulat, M E

    2011-12-01

    We describe the present status of an ongoing project to develop a Tandem-ElectroStatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based (AB)-BNCT. The project final goal is a machine capable of delivering 30 mA of 2.4 MeV protons to be used in conjunction with a neutron production target based on the (7)Li(p,n)(7)Be reaction. The machine currently being constructed is a folded TESQ with a high-voltage terminal at 0.6 MV. We report here on the progress achieved in a number of different areas.

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

    DOE PAGES

    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 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

  7. Development of a 15 T $Nb_3Sn$ Accelerator Dipole Demonstrator at Fermilab

    DOE PAGES

    Novitski, I.; Andreev, N.; Barzi, E.; Carmichael, J.; Kashikhin, V. V.; Turrion, D.; Yu, M.; Zlobin, A. V.

    2016-01-01

    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 $Nb_3Sn$ 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. Themore » 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

  8. Developing the new ANSI N43.4 accelerator safety standard

    NASA Astrophysics Data System (ADS)

    Walker, L. S.; Liu, J. C.

    1997-02-01

    A committee from across the USA and Canada is currently developing an update of the old ANSI N43.1 Standard titled: "Radiological Safety in the Design and Operation of Particle Accelerators." Prior to starting the update, we composed an outline of the new standard and set forth a basic list of reference documents. The committee's ANSI charter includes a directive to encompass all industrial and research accelerators regardless of size, intensity or beam power. The committee has adopted the graded approach which is used in NCRP report No. 88 "Radiation Alarms and Access Control Systems." The committee is composed of a nearly equal number of personnel from the research accelerator community, the regulatory community, and the commercial accelerator community. Accelerators from across the world have experienced an unacceptably high incidence of accidents over the past several years.1 The committee intends to addressing the problem and attempting to enumerate safe guards which will reduce the incidence of such occurrences. Current estimates of the time required to write the standard are between 12 and 18 months.

  9. 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.

  10. Flame resistant fibrous structures development

    NASA Technical Reports Server (NTRS)

    Coskren, Robert J.

    1992-01-01

    The purpose of the current program was (1) to investigate potentially useful new polymers, both for fire safety and mechanical properties, (2) to produce fibers from these polymers if necessary, and (3) to produce sufficient quantities of qualified fibrous structures, composites, or laminates for use in various areas of the Space Shuttle and Space Station Programs. During the past six years, development efforts have been expended in several major areas in support of Space Shuttle missions and Space Station Freedom projects. The summarized results of several of these major efforts are included in this report.

  11. 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.

  12. Structure-activity relationship of caffeoylquinic acids on the accelerating activity on ATP production.

    PubMed

    Miyamae, Yusaku; Kurisu, Manami; Han, Junkyu; Isoda, Hiroko; Shigemori, Hideyuki

    2011-01-01

    Caffeoylquinic acid (CQA) is one of the phenylpropanoids which have various bioactivities such as antioxidant, antibacterial, anticancer, antihistamic, and other biological effects. We previously reported that 3,5-di-O-caffeoylquinic acid inhibited amyloid β(1-42)-induced cellular toxicity on human neuroblastoma SH-SY5Y cells and increased the mRNA expression level of glycolytic enzymes and the intracellular ATP level. To investigate structure-activity relationship on the accelerating activity on ATP production, we synthesized 1,4,5-tri-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, 3,4,5-tri-O-caffeoylquinic acid, and other derivatives. Additionally, we evaluated intracellular ATP level in SH-SY5Y treated with each CQA derivative. As a result, 3,4,5-tri-O-caffeoylquinic acid showed the highest accelerating activity on ATP production among tested compounds. It was suggested that caffeoyl groups bound to quinic acid are important for activity and the more caffeoyl groups are bound to quinic acid, the higher accelerating activity on ATP production exhibits.

  13. 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.

  14. Accelerating universe and the time-dependent fine-structure constant

    NASA Astrophysics Data System (ADS)

    Fujii, Yasunori

    2010-11-01

    I start with assuming a gravitational scalar field as the dark-energy supposed to be responsible for the accelerating universe. Also from the point of view of unification, a scalar field implies a time-variability of certain “constants” in Nature. In this context I once derived a relation for the time-variability of the fine-structure constant α: Δα/α =ζ Ƶ(α/π) Δσ, where ζ and Ƶ are the constants of the order one, while σ on the right-hand side is the scalar field in action in the accelerating universe. I use the reduced Planckian units with c=ℏ =MP(=(8π G)-1/2)=1. I then compared the dynamics of the accelerating universe, on one hand, and Δα/α derived from the analyses of QSO absorption lines, Oklo phenomenon, also different atomic clocks in the laboratories, on the other hand. I am here going to discuss the theoretical background of the relation, based on the scalar-tensor theory invented first by Jordan in 1955.

  15. [Development and structure of proplastids].

    PubMed

    MUEHLETHALER, K; FREY-WYSSLING, A

    1959-12-01

    In this study the proplastid development in embryonic cells is described for the apical meristem of Elodea canadensis, embryo sacs from Lilies, and Begonia leaf buds. The formation of these cell organelles originates with submicroscopical particles which consist of a homogeneous stroma with a surrounding double membrane. When these proplastids reach an average size of 1 micro, the inner layer of the membrane begins to invaginate into the stroma. This process is comparable to tubuli formation in mitochondria. Under growth conditions with sufficient exposure to light, the development of the grana and stroma lamellae proceeds without interruption. If the plants are kept in the dark, small vesicles are formed which accumulate in the prolamellar body of the proplastids. After illumination these elementary vesicles merge to form membranes which evolve into grana and stroma lamellae. The structural similarity of the early proplastid stages with the mitochondria seems to indicate that there exists some phylogenetic relationship between the two cell organelles.

  16. 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.

  17. 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.

  18. 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.

  19. Temporal evolution and electric potential structure of the auroral acceleration region from multispacecraft measurements

    NASA Astrophysics Data System (ADS)

    Forsyth, C.; Fazakerley, A. N.; Walsh, A. P.; Watt, C. E.; Garza, K.; Owen, C. J.; Constantinescu, D. O.; Dandouras, I. S.; Fornacon, K.; Lucek, E. A.; Marklund, G. T.; Sadeghi, S. S.; Khotyaintsev, Y. V.; Masson, A.; Doss, N.

    2013-12-01

    Bright aurorae can be excited by the acceleration of electrons into the atmosphere in violation of ideal magnetohydrodynamics. Modelling studies predict that the accelerating electric potential consists of electric double layers at the boundaries of an acceleration region but observations suggest that particle acceleration occurs throughout this region. Using multispacecraft observations from Cluster, we have examined two upward current regions on 14 December 2009. Our observations show that the potential difference below C4 and C3 changed by up to 1.7 kV between their respective crossings, which were separated by 150 s. The field-aligned current density observed by C3 was also larger than that observed by C4. The potential drop above C3 and C4 was approximately the same in both crossings. Using a novel technique of quantitively comparing the electron spectra measured by Cluster 1 and 3, which were separated in altitude, we determine when these spacecraft made effectively magnetically conjugate observations, and we use these conjugate observations to determine the instantaneous distribution of the potential drop in the AAR. Our observations show that an average of 15% of the potential drop in the AAR was located between C1 at 6235 km and C3 at 4685 km altitude, with a maximum potential drop between the spacecraft of 500 V, and that the majority of the potential drop was below C3. Assuming a spatial invariance along the length of the upward current region, we discuss these observations in terms of temporal changes and the vertical structure of the electrostatic potential drop and in the context of existing models and previous single- and multispacecraft observations.

  20. Temporal evolution and electric potential structure of the auroral acceleration region from multispacecraft measurements

    NASA Astrophysics Data System (ADS)

    Forsyth, C.; Fazakerley, A. N.; Walsh, A. P.; Watt, C. E. J.; Garza, K. J.; Owen, C. J.; Constantinescu, D.; Dandouras, I.; FornaçOn, K.-H.; Lucek, E.; Marklund, G. T.; Sadeghi, S. S.; Khotyaintsev, Y.; Masson, A.; Doss, N.

    2012-12-01

    Bright aurorae can be excited by the acceleration of electrons into the atmosphere in violation of ideal magnetohydrodynamics. Modeling studies predict that the accelerating electric potential consists of electric double layers at the boundaries of an acceleration region but observations suggest that particle acceleration occurs throughout this region. Using multispacecraft observations from Cluster, we have examined two upward current regions on 14 December 2009. Our observations show that the potential difference below C4 and C3 changed by up to 1.7 kV between their respective crossings, which were separated by 150 s. The field-aligned current density observed by C3 was also larger than that observed by C4. The potential drop above C3 and C4 was approximately the same in both crossings. Using a novel technique of quantitively comparing the electron spectra measured by Cluster 1 and 3, which were separated in altitude, we determine when these spacecraft made effectively magnetically conjugate observations, and we use these conjugate observations to determine the instantaneous distribution of the potential drop in the AAR. Our observations show that an average of 15% of the potential drop in the AAR was located between C1 at 6235 km and C3 at 4685 km altitude, with a maximum potential drop between the spacecraft of 500 V, and that the majority of the potential drop was below C3. Assuming a spatial invariance along the length of the upward current region, we discuss these observations in terms of temporal changes and the vertical structure of the electrostatic potential drop and in the context of existing models and previous single- and multispacecraft observations.

  1. 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. PMID:26044364

  2. High power experimental studies of hybrid photonic band gap accelerator structures

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    This paper reports the first high power tests of hybrid photonic band gap (PBG) accelerator structures. Three hybrid PBG (HPBG) structures were designed, built and tested at 17.14 GHz. Each structure had a triangular lattice array with 60 inner sapphire rods and 24 outer copper rods sandwiched between copper disks. The dielectric PBG band gap map allows the unique feature of overmoded operation in a TM02 mode, with suppression of both lower order modes, such as the TM11 mode, as well as higher order modes. The use of sapphire rods, which have negligible dielectric loss, required inclusion of the dielectric birefringence in the design. The three structures were designed to sequentially reduce the peak surface electric field. Simulations showed relatively high surface fields at the triple point as well as in any gaps between components in the clamped assembly. The third structure used sapphire rods with small pin extensions at each end and obtained the highest gradient of 19 MV /m , corresponding to a surface electric field of 78 MV /m , with a breakdown probability of 5 ×10-1 per pulse per meter for a 100-ns input power pulse. Operation at a gradient above 20 MV /m led to runaway breakdowns with extensive light emission and eventual damage. For all three structures, multipactor light emission was observed at gradients well below the breakdown threshold. This research indicated that multipactor triggered at the triple point limited the operational gradient of the hybrid structure.

  3. 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.

  4. Recent developments in the application of electron accelerators for polymer processing

    NASA Astrophysics Data System (ADS)

    Chmielewski, A. G.; Al-Sheikhly, M.; Berejka, A. J.; Cleland, M. R.; Antoniak, M.

    2014-01-01

    There are now over 1700 high current, electron beam (EB) accelerators being used world-wide in industrial applications, most of which involve polymer processing. In contrast to the use of heat, which transfers only about 5-10% of input energy into energy useful for materials modification, radiation processing is very energy efficient, with 60% or more of the input energy to an accelerator being available for affecting materials. Historic markets, such as the crosslinking of wire and cable jacketing, of heat shrinkable tubings and films, of partial crosslinking of tire components and of low-energy EB to cure or dry inks and coatings remain strong. Accelerator manufacturers have made equipment more affordable by down-sizing units while maintaining high beam currents. Very powerful accelerators with 700 kW output have made X-ray conversion a practical alternative to the historic use of radioisotopes, mainly cobalt-60, for applications as medical device sterilization. New EB end-uses are emerging, such as the development of nano-composites and nano-gels and the use of EB processing to facilitate biofuel production. These present opportunities for future research and development.

  5. 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.

  6. 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.

  7. Evolutionary development of tensegrity structures.

    PubMed

    Lobo, Daniel; Vico, Francisco J

    2010-09-01

    Contributions from the emerging fields of molecular genetics and evo-devo (evolutionary developmental biology) are greatly benefiting the field of evolutionary computation, initiating a promise of renewal in the traditional methodology. While direct encoding has constituted a dominant paradigm, indirect ways to encode the solutions have been reported, yet little attention has been paid to the benefits of the proposed methods to real problems. In this work, we study the biological properties that emerge by means of using indirect encodings in the context of form-finding problems. A novel indirect encoding model for artificial development has been defined and applied to an engineering structural-design problem, specifically to the discovery of tensegrity structures. This model has been compared with a direct encoding scheme. While the direct encoding performs similarly well to the proposed method, indirect-based results typically outperform the direct-based results in aspects not directly linked to the nature of the problem itself, but to the emergence of properties found in biological organisms, like organicity, generalization capacity, or modularity aspects which are highly valuable in engineering. PMID:20619314

  8. Evolutionary development of tensegrity structures.

    PubMed

    Lobo, Daniel; Vico, Francisco J

    2010-09-01

    Contributions from the emerging fields of molecular genetics and evo-devo (evolutionary developmental biology) are greatly benefiting the field of evolutionary computation, initiating a promise of renewal in the traditional methodology. While direct encoding has constituted a dominant paradigm, indirect ways to encode the solutions have been reported, yet little attention has been paid to the benefits of the proposed methods to real problems. In this work, we study the biological properties that emerge by means of using indirect encodings in the context of form-finding problems. A novel indirect encoding model for artificial development has been defined and applied to an engineering structural-design problem, specifically to the discovery of tensegrity structures. This model has been compared with a direct encoding scheme. While the direct encoding performs similarly well to the proposed method, indirect-based results typically outperform the direct-based results in aspects not directly linked to the nature of the problem itself, but to the emergence of properties found in biological organisms, like organicity, generalization capacity, or modularity aspects which are highly valuable in engineering.

  9. Accelerated electronic structure-based molecular dynamics simulations of shock-induced chemistry

    NASA Astrophysics Data System (ADS)

    Cawkwell, Marc

    2015-06-01

    The initiation and progression of shock-induced chemistry in organic materials at moderate temperatures and pressures are slow on the time scales available to regular molecular dynamics simulations. Accessing the requisite time scales is particularly challenging if the interatomic bonding is modeled using accurate yet expensive methods based explicitly on electronic structure. We have combined fast, energy conserving extended Lagrangian Born-Oppenheimer molecular dynamics with the parallel replica accelerated molecular dynamics formalism to study the relatively sluggish shock-induced chemistry of benzene around 13-20 GPa. We model interatomic bonding in hydrocarbons using self-consistent tight binding theory with an accurate and transferable parameterization. Shock compression and its associated transient, non-equilibrium effects are captured explicitly by combining the universal liquid Hugoniot with a simple shrinking-cell boundary condition. A number of novel methods for improving the performance of reactive electronic structure-based molecular dynamics by adapting the self-consistent field procedure on-the-fly will also be discussed. The use of accelerated molecular dynamics has enabled us to follow the initial stages of the nucleation and growth of carbon clusters in benzene under thermodynamic conditions pertinent to experiments.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Can Accelerators Accelerate Learning?

    SciTech Connect

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

    2009-03-10

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Acceleration Data Reveal Highly Individually Structured Energetic Landscapes in Free-Ranging Fishers (Pekania pennanti).

    PubMed

    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

  20. 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.

  1. Development of a tandem-electrostatic-quadrupole accelerator facility for BNCT.

    PubMed

    Kreiner, A J; Thatar Vento, V; Levinas, P; Bergueiro, J; Di Paolo, H; Burlon, A A; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Minsky, D M; Estrada, L; Hazarabedian, A; Johann, F; Suarez Sandin, J C; Castell, W; Davidson, J; Davidson, M; Giboudot, Y; Repetto, M; Obligado, M; Nery, J P; Huck, H; Igarzabal, M; Fernandez Salares, A

    2009-07-01

    In this work we describe the present status of an ongoing project to develop a tandem-electrostatic-quadrupole (TESQ) accelerator facility for accelerator-based (AB) BNCT at the Atomic Energy Commission of Argentina in Buenos Aires. The project final goal is a machine capable of delivering 30 mA of 2.4 MeV protons to be used in conjunction with a neutron production target based on the (7)Li(p,n)(7)Be reaction slightly beyond its resonance at 2.25 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the (7)Li(p,n)(7)Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. An electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT. The machine being designed and constructed is a folded TESQ with a high-voltage terminal at 1.2 MV intended to work in air. Such a machine is conceptually shown to be capable of transporting and accelerating a 30 mA proton beam to 2.4 MeV. The general geometric layout, its associated electrostatic fields, and the acceleration tube are simulated using a 3D finite element procedure. The design and construction of the ESQ modules is discussed and their electrostatic fields are investigated. Beam transport calculations through the accelerator are briefly mentioned. Likewise, work related to neutron production targets, strippers, beam shaping assembly and patient treatment room is briefly described.

  2. Fetal dexamethasone exposure accelerates development of renal function: relationship to dose, cell differentiation and growth inhibition.

    PubMed

    Slotkin, T A; Seidler, F J; Kavlock, R J; Gray, J A

    1992-02-01

    Fetal exposure to high doses of glucocorticoids slows cellular development and impairs organ performance, in association with growth retardation. Nevertheless, low doses of glucocorticoids may enhance cell differentiation and accelerate specific functions. The current study examined this apparent paradox in the developing rat kidney, using doses of dexamethasone that span the threshold for growth impairment: 0.05 or 0.2 mg/kg given on gestational days 17, 18 and 19. At the lower dose, which did not significantly retard body growth, the postnatal development of tubular reabsorptive capabilities for sodium, potassium, osmotic particles, water and urea was accelerated. These effects were less notable at the higher dose, which caused initial body growth impairment. The selectivity toward promotion of tubular function was evidenced by the absence of effect of either dose of dexamethasone on development of glomerular filtration rate. Because of the wide spectrum of dexamethasone's effects on tubular function, we also assessed fetal kidney adenylate cyclase as a means of detecting altered cell differentiation in the prenatal period during which dexamethasone was given. Either glucocorticoid dose increased the total adenylate cyclase catalytic activity (assessed with forskolin). Thus, the net effect of fetal dexamethasone exposure on development of renal excretory capabilities probably represents the summation of promoted cell differentiation and slowed development consequent to growth retardation. At low dose levels, the former effect predominates, leading to enhanced functional development, whereas higher doses that interfere with general growth and development can offset the direct promotional effect.

  3. 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.

  4. 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.

  5. PARTICLE ACCELERATION IN PLASMOID EJECTIONS DERIVED FROM RADIO DRIFTING PULSATING STRUCTURES

    SciTech Connect

    Nishizuka, N.; Karlický, M.; Bárta, M.; Janvier, M.

    2015-02-01

    We report observations of slowly drifting pulsating structures (DPSs) in the 0.8-4.5 GHz frequency range of the RT4 and RT5 radio spectrographs at Ondřejov Observatory, between 2002 and 2012. We found 106 events of DPSs, which we classified into four cases: (I) single events with a constant frequency drift (12 events), (II) multiple events occurring in the same flare with constant frequency drifts (11 events), (III) single or multiple events with increasing or decreasing frequency drift rates (52 events), and (IV) complex events containing multiple events occurring at the same time in a different frequency range (31 events). Many DPSs are associated with hard X-ray (HXR) bursts (15-25 keV) and soft X-ray (SXR) gradient peaks, as they typically occurred at the beginning of HXR peaks. This indicates that DPS events are related to the processes of fast energy release and particle acceleration. Furthermore, interpreting DPSs as signatures of plasmoids, we measured their ejection velocity, their width, and their height from the DPS spectra, from which we also estimated the reconnection rate and the plasma beta. In this interpretation, constant frequency drift indicates a constant velocity of a plasmoid, and an increasing/decreasing frequency drift indicates a deceleration/acceleration of a plasmoid ejection. The reconnection rate shows a good positive correlation with the plasmoid velocity. Finally we confirmed that some DPS events show plasmoid counterparts in Solar Dynamics Observatory/Atmospheric Imaging Assembly images.

  6. Selection of flowing liquid lead target structural materials for accelerator driven transmutation applications

    SciTech Connect

    Park, J.J.; Buksa, J.J.

    1994-08-01

    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.

  7. 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.

  8. 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.

  9. Narrow bandwidth Thomson photon source development using Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Geddes, C. G. R.; Steinke, S.; Tsai, H.-E.; Rykovanov, S. G.; Vay, J.-L.; Bonatto, A.; Benedetti, C.; Schroeder, C. B.; Esarey, E.; Friedman, A.; Grote, D. P.; Leemans, W. P.

    2015-11-01

    Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs). Simulations are presented on production of controllable narrow bandwidth sources using the beam and plasma capabilities of LPAs. An independent scattering laser, combined with appropriate pulse shaping and laser guiding is important to realize high photon yield. Plasma optics are described to tailor beam divergence in cm-scale distances, reducing photon source bandwidth. The LPA can further be used to de-accelerate the electron beam after photon production to reduce undesired radiation. Combination of laser driven and beam driven deceleration is presented to reduce residual beam energy, as is important for a laboratory or field operable source. Design of experiments and laser capabilities to combine these elements will be presented, towards a compact photon source system.

  10. 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.

  11. Multiple quasi-monoenergetic electron beams from laser-wakefield acceleration with spatially structured laser pulse

    SciTech Connect

    Ma, Y.; Li, M. H.; Li, Y. F.; Wang, J. G.; Tao, M. Z.; Han, Y. J.; Zhao, J. R.; Huang, K.; Yan, W. C.; Ma, J. L.; Li, Y. T.; Chen, L. M.; Li, D. Z.; Chen, Z. Y.; Sheng, Z. M.; Zhang, J.

    2015-08-15

    By adjusting the focus geometry of a spatially structured laser pulse, single, double, and treble quasi-monoenergetic electron beams were generated, respectively, in laser-wakefield acceleration. Single electron beam was produced as focusing the laser pulse to a single spot. While focusing the laser pulse to two spots that are approximately equal in energy and size and intense enough to form their own filaments, two electron beams were produced. Moreover, with a proper distance between those two focal spots, three electron beams emerged with a certain probability owing to the superposition of the diffractions of those two spots. The energy spectra of the multiple electron beams are quasi-monoenergetic, which are different from that of the large energy spread beams produced due to the longitudinal multiple-injection in the single bubble.

  12. 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.

  13. 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.

  14. Increasing Spontaneous Retinal Activity before Eye Opening Accelerates the Development of Geniculate Receptive Fields

    PubMed Central

    Davis, Zachary W.; Chapman, Barbara

    2015-01-01

    Visually evoked activity is necessary for the normal development of the visual system. However, little is known about the capacity for patterned spontaneous activity to drive the maturation of receptive fields before visual experience. Retinal waves provide instructive retinotopic information for the anatomical organization of the visual thalamus. To determine whether retinal waves also drive the maturation of functional responses, we increased the frequency of retinal waves pharmacologically in the ferret (Mustela putorius furo) during a period of retinogeniculate development before eye opening. The development of geniculate receptive fields after receiving these increased neural activities was measured using single-unit electrophysiology. We found that increased retinal waves accelerate the developmental reduction of geniculate receptive field sizes. This reduction is due to a decrease in receptive field center size rather than an increase in inhibitory surround strength. This work reveals an instructive role for patterned spontaneous activity in guiding the functional development of neural circuits. SIGNIFICANCE STATEMENT Patterned spontaneous neural activity that occurs during development is known to be necessary for the proper formation of neural circuits. However, it is unknown whether the spontaneous activity alone is sufficient to drive the maturation of the functional properties of neurons. Our work demonstrates for the first time an acceleration in the maturation of neural function as a consequence of driving patterned spontaneous activity during development. This work has implications for our understanding of how neural circuits can be modified actively to improve function prematurely or to recover from injury with guided interventions of patterned neural activity. PMID:26511250

  15. 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…

  16. 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.

  17. Beam-based measurements of long-range transverse wakefields in the Compact Linear Collider main-linac accelerating structure

    NASA Astrophysics Data System (ADS)

    Zha, Hao; Latina, Andrea; Grudiev, Alexej; De Michele, Giovanni; Solodko, Anastasiya; Wuensch, Walter; Schulte, Daniel; Adli, Erik; Lipkowitz, Nate; Yocky, Gerald S.

    2016-01-01

    The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures for its main linacs. In order to maintain beam stability in multibunch operation, long-range transverse wakefields must be suppressed by 2 orders of magnitude between successive bunches, which are separated in time by 0.5 ns. Such strong wakefield suppression is achieved by equipping every accelerating structure cell with four damping waveguides terminated with individual rf loads. A beam-based experiment to directly measure the effectiveness of this long-range transverse wakefield and benchmark simulations was made in the FACET test facility at SLAC using a prototype CLIC accelerating structure. The experiment showed good agreement with the simulations and a strong suppression of the wakefields with an unprecedented minimum resolution of 0.1 V /(pC mm m ) .

  18. 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

  19. 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.

  20. 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

  1. 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…

  2. 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.

  3. Development of backsheet tests and measurements to improve correlation of accelerated exposures to fielded modules

    NASA Astrophysics Data System (ADS)

    Felder, Thomas C.; Gambogi, William J.; Kopchick, James G.; Amspacher, Lucas; Peacock, R. Scott; Foltz, Benjamin; Stika, Katherine M.; Bradley, Alexander Z.; Hamzavy, Babak; Yu, Bao-Ling; Garreau-iles, Lucie; Fu, Oakland; Hu, Hongjie; Trout, T. John

    2015-09-01

    Matching accelerated test results to field observations is an important objective in the photovoltaic industry. We continue to develop test methods to strengthen correlations. We have previously reported good correlation of FTIR spectra between accelerated tests and field measurements. The availability of portable FTIR spectrometers has made measurement in the field convenient and reliable. Recently, nano-indentation has shown promise to correlate changes in backsheet mechanical properties. A precisely shaped stylus is pressed into a sample, load vs displacement recorded and mechanical properties of interest calculated in a nondestructive test. This test can be done on full size modules, allowing area variations in mechanical properties to be recorded. Finally, we will discuss optical profilometry. In this technique a white light interferogram of a surface is Fourier transformed to produce a three-dimensional image. Height differences from 1 nm to 5 mm can be detected over an area of a few cm. This technique can be used on minimodules, and is useful to determine crack and defect dimensions. Results will be presented correlating accelerated tests with fielded modules covering spectroscopic, mechanical, and morphological changes.

  4. 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.

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

    SciTech Connect

    Geddes, Cameron GR; Bruhwiler, David L.; Cary, John R.; Esarey, Eric H.; Gonsalves, Anthony J.; Lin, Chen; Cormier-Michel, Estelle; Matlis, Nicholas H.; Nakamura, Kei; Bakeman, Mike; Panasenko, Dmitriy; Plateau, Guillaume R.; Schroeder, Carl B.; Toth, Csaba; Leemans, Wim P.

    2008-09-08

    Compact high-energy linacs are important to applications including monochromatic gamma sources for nuclear material security applications. Recent laser wakefield accelerator experiments at LBNL demonstrated narrow energy spread beams, now with energies of up to 1 GeV in 3 cm using a plasma channel at low density. This demonstrates the production of GeV beams from devices much smaller than conventional linacs, and confirms the anticipated scaling of laser driven accelerators to GeV energies. Stable performance at 0.5 GeV was demonstrated. Experiments and simulations are in progress to control injection of particles into the wake and hence to improve beam quality and stability. Using plasma density gradients to control injection, stable beams at 1 MeV over days of operation, and with an order of magnitude lower absolute momentum spread than previously observed, have been demonstrated. New experiments are post-accelerating the beams from controlled injection experiments to increase beam quality and stability. Thomson scattering from such beams is being developed to provide collimated multi-MeV monoenergetic gamma sources for security applications from compact devices. Such sources can reduce dose to target and increase accuracy for applications including photofission and nuclear resonance fluorescence.

  6. Development of a multiplexed electrospray micro-thruster with post-acceleration and beam containment

    NASA Astrophysics Data System (ADS)

    Lenguito, G.; Gomez, A.

    2013-10-01

    We report the development of a compact thruster based on Multiplexed ElectroSprays (MES). It relied on a microfabricated Si array of emitters coupled with an extractor electrode and an accelerator electrode. The accelerator stage was introduced for two purposes: containing beam opening and avoiding electrode erosion due to droplet impingement, as well as boosting specific impulse and thrust. Multiplexing is generally necessary as a thrust multiplier to reach eventually the level required (O(102) μN) by small satellites. To facilitate system optimization and debugging, we focused on a 7-nozzle MES device and compared its performance to that of a single emitter. To ensure uniformity of operation of all nozzles their hydraulic impedance was augmented by packing them with micrometer-size beads. Two propellants were tested: a solution of 21.5% methyl ammonium formate in formamide and the better performing pure ionic liquid ethyl ammonium nitrate (EAN). The 7-MES device spraying EAN at ΔV = 5.93 kV covered a specific impulse range from 620 s to 1900 s and a thrust range from 0.6 μN to 5.4 μN, at 62% efficiency. Remarkably, less than 1% of the beam was demonstrated to impact on the accelerator electrode, which bodes well for long-term applications in space.

  7. 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.

  8. 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.

  9. 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.

  10. Increasing Spontaneous Retinal Activity before Eye Opening Accelerates the Development of Geniculate Receptive Fields.

    PubMed

    Davis, Zachary W; Chapman, Barbara; Cheng, Hwai-Jong

    2015-10-28

    Visually evoked activity is necessary for the normal development of the visual system. However, little is known about the capacity for patterned spontaneous activity to drive the maturation of receptive fields before visual experience. Retinal waves provide instructive retinotopic information for the anatomical organization of the visual thalamus. To determine whether retinal waves also drive the maturation of functional responses, we increased the frequency of retinal waves pharmacologically in the ferret (Mustela putorius furo) during a period of retinogeniculate development before eye opening. The development of geniculate receptive fields after receiving these increased neural activities was measured using single-unit electrophysiology. We found that increased retinal waves accelerate the developmental reduction of geniculate receptive field sizes. This reduction is due to a decrease in receptive field center size rather than an increase in inhibitory surround strength. This work reveals an instructive role for patterned spontaneous activity in guiding the functional development of neural circuits. PMID:26511250

  11. 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.

  12. Development of electron beam accelerator for SEPAC experiment on Spacelab One

    NASA Astrophysics Data System (ADS)

    Kawashima, N.; Kudo, I.; Goma, K.

    Design and performance features of the electron beam accelerator (EBA) to be used on the SEPAC experiment on the Spacelab One Shuttle mission are described. The EBA comprises an electron gun, power supply, and a high voltage converter (HVC). Numerical models were developed for the functional performances of the 20 mm diam beam intensity and the focusing and deflection coils. Functional features of the anode, heater, focusing and deflection and auxiliary power supply systems, and the HVC, controller, and redundancy features are provided. A mission simulation, verified that all mission objectives could be met with the device, including avoidance of electromagnetic interference with other Shuttle activities and equipment.

  13. 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.

  14. Structure development in magnetic paints

    SciTech Connect

    Potanin, A.A.; Shrauti, S.M.; Lane, A.M.; Arnold, D.W.

    1996-12-31

    Dynamic rheological measurements are used to probe the structure of model magnetic paints which contain ferro-magnetic particles of iron oxide or barium ferrite a wetting resin and a solvent. Along with industrially used organic solvent-based paints, water-borne systems are studied. Methods to characterize the dispersion quality of pigment particles through rheological measurements are outlined.

  15. 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.

  16. Soil Potassium Deficiency Reduces Cotton Fiber Strength by Accelerating and Shortening Fiber Development

    PubMed Central

    Yang, Jia-Shuo; Hu, Wei; Zhao, Wenqing; Meng, Yali; Chen, Binglin; Wang, Youhua; Zhou, Zhiguo

    2016-01-01

    Low potassium (K)-induced premature senescence in cotton has been observed worldwide, but how it affects cotton fiber properties remain unclear. We hypothesized that K deficiency affects cotton fiber properties by causing disordered fiber development, which may in turn be caused by the induction of a carbohydrate acquisition difficulty. To investigate this issue, we employed a low-K-sensitive cotton cultivar Siza 3 and a low-K-tolerant cultivar Simian 3 and planted them in three regions of different K supply. Data concerning lint yield, Pn and main fiber properties were collected from three years of testing. Soil K deficiency significantly accelerated fiber cellulose accumulation and dehydration processes, which, together with previous findings, suggests that the low-K induced carbohydrate acquisition difficulty could cause disordered fiber development by stimulating the expression of functional proteins such as CDKA (cyclin-dependent kinase). As a result, fiber strength and lint weight were reduced by up to 7.8% and 2.1%, respectively. Additional quantitative analysis revealed that the degree of accelerated fiber development negatively correlated with fiber strength. According to the results of this study, it is feasible to address the effects of soil K deficiency on fiber properties using existing cultivation strategies to prevent premature senescence of cotton plants. PMID:27350236

  17. 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.

  18. Word Structures of Granada Spanish-Speaking Preschoolers with Typical versus Protracted Phonological Development

    ERIC Educational Resources Information Center

    May Bernhardt, B.; Hanson, R.; Perez, D.; Ávila, C.; Lleó, C.; Stemberger, J. P.; Carballo, G.; Mendoza, E.; Fresneda, D.; Chávez-Peón, M.

    2015-01-01

    Background: Research on children's word structure development is limited. Yet, phonological intervention aims to accelerate the acquisition of both speech-sounds and word structure, such as word length, stress or shapes in CV sequences. Until normative studies and meta-analyses provide in-depth information on this topic, smaller investigations can…

  19. ConnectViz: Accelerated Approach for Brain Structural Connectivity Using Delaunay Triangulation.

    PubMed

    Adeshina, A M; Hashim, R

    2016-03-01

    Stroke is a cardiovascular disease with high mortality and long-term disability in the world. Normal functioning of the brain is dependent on the adequate supply of oxygen and nutrients to the brain complex network through the blood vessels. Stroke, occasionally a hemorrhagic stroke, ischemia or other blood vessel dysfunctions can affect patients during a cerebrovascular incident. Structurally, the left and the right carotid arteries, and the right and the left vertebral arteries are responsible for supplying blood to the brain, scalp and the face. However, a number of impairment in the function of the frontal lobes may occur as a result of any decrease in the flow of the blood through one of the internal carotid arteries. Such impairment commonly results in numbness, weakness or paralysis. Recently, the concepts of brain's wiring representation, the connectome, was introduced. However, construction and visualization of such brain network requires tremendous computation. Consequently, previously proposed approaches have been identified with common problems of high memory consumption and slow execution. Furthermore, interactivity in the previously proposed frameworks for brain network is also an outstanding issue. This study proposes an accelerated approach for brain connectomic visualization based on graph theory paradigm using compute unified device architecture, extending the previously proposed SurLens Visualization and computer aided hepatocellular carcinoma frameworks. The accelerated brain structural connectivity framework was evaluated with stripped brain datasets from the Department of Surgery, University of North Carolina, Chapel Hill, USA. Significantly, our proposed framework is able to generate and extract points and edges of datasets, displays nodes and edges in the datasets in form of a network and clearly maps data volume to the corresponding brain surface. Moreover, with the framework, surfaces of the dataset were simultaneously displayed with the

  20. 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. PMID:25201226

  1. WIPO Re:Search: Accelerating anthelmintic development through cross-sector partnerships

    PubMed Central

    Ramamoorthi, Roopa; Graef, Katy M.; Dent, Jennifer

    2014-01-01

    Neglected tropical diseases (NTDs), malaria, and tuberculosis have a devastating effect on an estimated 1.6 billion people worldwide. The World Intellectual Property Organization (WIPO) Re:Search consortium accelerates the development of new drugs, vaccines, and diagnostics for these diseases by connecting the assets and resources of pharmaceutical companies, such as compound libraries and expertise, to academic or nonprofit researchers with novel product discovery or development ideas. As the WIPO Re:Search Partnership Hub Administrator, BIO Ventures for Global Health (BVGH) fields requests from researchers, identifies Member organizations able to fulfill these requests, and helps forge mutually beneficial collaborations. Since its inception in October 2011, WIPO Re:Search membership has expanded to more than 90 institutions, including leading pharmaceutical companies, universities, nonprofit research institutions, and product development partnerships from around the world. To date, WIPO Re:Search has facilitated over 70 research agreements between Consortium Members, including 11 collaborations focused on anthelmintic drug discovery. PMID:25516832

  2. 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.

  3. 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

  4. A piezo-driven micro-inclination stage for calibration of a micro-acceleration transducer: structure and control strategy

    NASA Astrophysics Data System (ADS)

    Shao, Shubao; Song, Siyang; Xu, Minglong; Xie, Shilin; Li, Liang

    2016-02-01

    In some space applications, such as space navigation and vibration control of the large space structures, micro-acceleration transducers are required and have to be calibrated accurately. Unfortunately, providing extremely small static and quasi-static stimuli (accelerations) for the calibration of the micro-acceleration transducer has been a challenging task. This paper proposes a novel piezo-driven micro-inclination stage (PMIS) that can produce both discrete and continuous tumbles in a gravity field so that extremely small static and quasi-static stimuli (accelerations) can be obtained from a tiny component of the gravity constant. The proposed PMIS, which is driven by the lead zirconate titanate (PZT) stack, employs a rhombic mechanism to provide the PZT stack with a proper preload for the purpose of outputting a bidirectional force. To produce accurate static and quasi-static stimuli, the hysteresis non-linearity inherent in PZT stack is compensated by employing the strain feedback based adaptive control where the hysteresis property is identified online using the controlled auto-regressive moving average model. Furthermore, to improve the resolution of strain feedback, the strain sensitivity is maximized through structure optimization of the rhombic mechanism. The experimental results demonstrated that the proposed PMIS can produce minimal micro-inclination of {{0.1}\\prime \\prime} (corresponding to the induced micro-acceleration of 0.5μ g ) with the frequency ranging from 0 (DC) to 2 Hz.

  5. 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.

  6. 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.

  7. Socioeconomic status and structural brain development.

    PubMed

    Brito, Natalie H; Noble, Kimberly G

    2014-01-01

    Recent advances in neuroimaging methods have made accessible new ways of disentangling the complex interplay between genetic and environmental factors that influence structural brain development. In recent years, research investigating associations between socioeconomic status (SES) and brain development have found significant links between SES and changes in brain structure, especially in areas related to memory, executive control, and emotion. This review focuses on studies examining links between structural brain development and SES disparities of the magnitude typically found in developing countries. We highlight how highly correlated measures of SES are differentially related to structural changes within the brain.

  8. Socioeconomic status and structural brain development

    PubMed Central

    Brito, Natalie H.; Noble, Kimberly G.

    2014-01-01

    Recent advances in neuroimaging methods have made accessible new ways of disentangling the complex interplay between genetic and environmental factors that influence structural brain development. In recent years, research investigating associations between socioeconomic status (SES) and brain development have found significant links between SES and changes in brain structure, especially in areas related to memory, executive control, and emotion. This review focuses on studies examining links between structural brain development and SES disparities of the magnitude typically found in developing countries. We highlight how highly correlated measures of SES are differentially related to structural changes within the brain. PMID:25249931

  9. Socioeconomic status and structural brain development.

    PubMed

    Brito, Natalie H; Noble, Kimberly G

    2014-01-01

    Recent advances in neuroimaging methods have made accessible new ways of disentangling the complex interplay between genetic and environmental factors that influence structural brain development. In recent years, research investigating associations between socioeconomic status (SES) and brain development have found significant links between SES and changes in brain structure, especially in areas related to memory, executive control, and emotion. This review focuses on studies examining links between structural brain development and SES disparities of the magnitude typically found in developing countries. We highlight how highly correlated measures of SES are differentially related to structural changes within the brain. PMID:25249931

  10. Development of a quantitative accelerated sulphate attack test for mine backfill

    NASA Astrophysics Data System (ADS)

    Shnorhokian, Shahe

    Mining operations produce large amounts of tailings that are either disposed of in surface impoundments or used in the production of backfill to be placed underground. Their mineralogy is determined by the local geology, and it is not uncommon to come across tailings with a relatively high sulphide mineral content, including pyrite and pyrrhotite. Sulphides oxidize in the presence of oxygen and water to produce sulphate and acidity. In the concrete industry, sulphate is known to produce detrimental effects by reacting with the cement paste to produce the minerals ettringite and gypsum. Because mine backfill uses tailings and binders---including cement---it is therefore prone to sulphate attack where the required conditions are met. Currently, laboratory tests on mine backfill mostly measure mechanical properties such as strength parameters, and the study of the chemical aspects is restricted to the impact of tailings on the environment. The potential of sulphate attack in mine backfill has not been studied at length, and no tests are conducted on binders used in backfill for their resistance to attack. Current ASTM guidelines for sulphate attack tests have been deemed inadequate by several authors due to their measurement of only expansion as an indicator of attack. Furthermore, the tests take too long to perform or are restricted to cement mortars only, and not to mixed binders that include pozzolans. Based on these, an accelerated test for sulphate attack was developed in this work through modifying and compiling procedures that had been suggested by different authors. Small cubes of two different binders were fully immersed in daily-monitored sodium sulphate and sulphuric acid solutions for a total of 28 days, after 7 days of accelerated curing at 50°C. In addition, four binders were partially immersed in the same solutions for 8 days for an accelerated attack process. The two procedures were conducted in tandem with leach tests using a mixed solution of

  11. 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.

  12. High voltage hall accelerator propulsion system development for NASA science missions

    NASA Astrophysics Data System (ADS)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Shastry, Rohit; Pinero, Luis; Peterson, Todd; Dankanich, John; Mathers, Alex

    NASA Science Mission Directorate's 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 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.

  13. 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. PMID:26736424

  14. Aggressive, accelerated subdomain smoothers for Stokes flow with highly heterogeneous viscosity structure

    NASA Astrophysics Data System (ADS)

    Sanan, Patrick; May, Dave; Schenk, Olaf; Rupp, Karl

    2016-04-01

    Scalable solvers for mantle convection and lithospheric dynamics with highly heterogeneous viscosity structure typically require the use of a multigrid method. To leverage new hybrid CPU-accelerator architectures on leadership compute clusters, multigrid hierarchies which can reduce communication and use high available arithmetic intensity are at a premium, motivating more aggressive coarsening schemes and smoothers. We present results of a comparative study of two competitive GPU-enabled subdomain smoothers within an additive Schwarz method. Chebyshev-Jacobi smoothing has been shown to be an effective smoother, and its nature as a low-communication method built from basic linear algebra routines allows its use on a wide range of devices with current libraries. ILU smoothing is also of interest and is known to provide robust smoothing in some cases, but has traditionally been difficult to use in a fine-grained parallel environment. However, a recently-introduced variant by Chow and Patel allows for incomplete factorizations to be computed and applied in these environments, hence allowing us to study them as well. We use and extend the pTatin3D, PETSc, and ViennaCL libraries to integrate promising methods into a realistic application framework.

  15. Beta/A4 proteinlike immunoreactive granular structures in the brain of senescence-accelerated mouse.

    PubMed Central

    Takemura, M.; Nakamura, S.; Akiguchi, I.; Ueno, M.; Oka, N.; Ishikawa, S.; Shimada, A.; Kimura, J.; Takeda, T.

    1993-01-01

    The immunohistochemical localization of amyloid beta/A4 protein in the senescence-accelerated mouse brain was studied using six different antisera against human amyloid precursor protein peptides. beta/A4 proteinlike immunoreactivity was observed in the form of granular structures (beta-LIGS) in various regions, including the medial septum, cerebral cortex, hippocampus, cerebellum, and some cranial nerve roots. beta-LIGS were 1.5 to 2.5 mu in diameter and irregularly shaped. They increased significantly in number with aging, predominantly in animals with a phenotype of age-related deterioration of memory and learning abilities. Congo red and thioflavine S did not stain the granules. On immunoblots, the main immunoreactive bands were observed at 14 to 18 kd. The staining intensities of these bands also increased with advancing age. We consider that beta-LIGS are not only a new morphological manifestation of senescence in mice, but also a pertinent clue in understanding the mechanisms of amyloid deposition. Images Figure 1 Figure 3 Figure 4 PMID:8506956

  16. Biological effectiveness of accelerated particles for the induction of chromosome damage: track structure effects.

    PubMed

    George, Kerry A; Hada, Megumi; Chappell, Lori; Cucinotta, Francis A

    2013-07-01

    We have investigated how radiation quality affects the induction of chromosomal aberrations in human cells. Human lymphocytes were irradiated in vitro with various energies of accelerated high charge and energy (HZE) particles including oxygen, neon, silicon, titanium and iron. Chromosome damage was assessed using three-color FISH chromosome painting in chemically induced premature chromosome condensation samples collected at first cell division after irradiation. The LET values for these particles ranged from 30 to 195 keV/μm, and their energies ranged from about 55 MeV/u to more than 1,000 MeV/u. The 89 and 142 MeV/u neon particles produced the most simple-type reciprocal exchanges per unit dose. For complex-type exchanges, 64 MeV/u neon and 450 MeV/u iron were equally effective and induced the greatest amount of complex damage. 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, and that a saturation cross section will be observed for different radiation qualities. Our results are consistent with model expectations within the limitation of experimental error, and provide the most extensive data that have been reported on the radiation quality dependences of chromosomal aberrations. PMID:23692480

  17. 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

  18. 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.

  19. Piriformospora indica mycorrhization increases grain yield by accelerating early development of barley plants

    PubMed Central

    Achatz, Beate; Kogel, Karl-Heinz; Franken, Philipp

    2010-01-01

    Root colonization by the basidiomycete fungus Piriformospora indica induces host plant tolerance against abiotic and biotic stress, and enhances growth and yield. As P. indica has a broad host range, it has been established as a model system to study beneficial plant-microbe interactions. Moreover, its properties led to the assumption that P. indica shows potential for application in crop plant production. Therefore, possible mechanisms of P. indica improving host plant yield were tested in outdoor experiments: Induction of higher grain yield in barley was independent of elevated pathogen levels and independent of different phosphate fertilization levels. In contrast to the arbuscular mycorrhiza fungus Glomus mosseae total phosphate contents of host plant roots and shoots were not significantly affected by P. indica. Analysis of plant development and yield parameters indicated that positive effects of P. indica on grain yield are due to accelerated growth of barley plants early in development. PMID:21150264

  20. Photoinduced acceleration of the effluent rate of developing solvents in azobenzene-tethered silica gel.

    PubMed

    Fujiwara, Masahiro; Akiyama, Minako; Hata, Momoko; Shiokawa, Kumi; Nomura, Ryoki

    2008-08-01

    The switching of a molecular length of azobenzene between its trans and cis forms by photoirradiation originates various photoresponsive systems in the molecular level and/or nanolevel. Recently, we and another group separately reported that some azobenzene-modified mesoporous silicas remarkably promote the release of molecules from the inside of the mesopore to the outside, when the lights, both UV and visible lights, were irradiated simultaneously. In these cases, the release rates of molecules were enhanced by the impeller-like effect of molecular motion of azobenzene moiety attributed to the continuous photoisomerization between the trans and cis isomers. This paper presents that azobenzene-substituent-tethered amorphous silica gel could promote the development of solvents in chromatography systems by photoirradiation. In column chromatography system where azobenzene-tethered silica gel was packed, the irradiation of both UV and visible lights increased the effluent rate of the developing solvents. The single irradiation of UV light scarcely enhanced the rate, while the visible light irradiation longer than 400 nm in wavelength also accelerated the development of the solvent moderately. The same kinds of phenomena were observed when this photopromoted chromatography system was applied to thin layer chromatography (TLC). Hydrocarbon developing solvents in the regions, where UV and visible lights were irradiated, moved up the TLC plate higher than those without photoirradiation. When the pyrene solution in the developing solvent was utilized in the chromatography systems, the similar photoacceleration of pyrene development was observed at the same level as the developing solvents.

  1. Structural changes in the O-decay accelerated mutants of pharaonis phoborhodopsin.

    PubMed

    Sudo, Yuki; Furutani, Yuji; Iwamoto, Masayuki; Kamo, Naoki; Kandori, Hideki

    2008-03-01

    pharaonis phoborhodopsin ( ppR, also called pharaonis sensory rhodopsin II, psRII) is a receptor for negative phototaxis in Natronomonas pharaonis. The X-ray crystallographic structure of ppR is very similar to those of the ion-pumping rhodopsins, bacteriorhodopsin (BR) and halorhodopsin (hR). However, the decay processes of the photocycle intermediates such as M and O are much slower than those of BR and hR, which is advantageous for the sensor function of ppR. Iwamoto et al. previously found that, in a quadruple mutant (P182S/P183E/V194T/T204C; denoted as SETC) of ppR, the decay of the O intermediate was accelerated by approximately 100 times ( t 1/2 approximately 6.6 ms vs 690 ms for the wild type of ppR), being almost equal to that of BR (Iwamoto, M., et al. (2005) Biophys. J. 88, 1215-1223). The mutated residues are located on the extracellular surface (Pro182, Pro183, and Val194) and near the Schiff base (Thr204). The present Fourier-transform infrared (FTIR) spectroscopy of SETC revealed that protein structural changes in the K and M states were similar to those of the wild type. In contrast, the ppR O minus ppR infrared difference spectra of SETC are clearly different from those of the wild type in amide-I (1680-1640 cm (-1)) and S-H stretching (2580-2520 cm (-1)) vibrations. The 1673 (+) and 1656 (-) cm (-1) bands newly appear for SETC in the frequency region typical for the amide-I vibration of the alpha II- and alpha I-helices, respectively. The intensities of the 1673 (+) cm (-1) band of various mutants were well correlated with their O-decay half-times. Since the alpha II-helix possesses a considerably distorted structure, the result implies that distortion of the helix is required for fast O-decay. In addition, the characteristic changes in the S-H stretching vibration of Cys204 were different between SETC and T204C, suggesting that structural change near the Schiff base was induced by mutations of the extracellular surface. We conclude that the

  2. 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

  3. Particle acceleration in pulsar magnetospheres

    NASA Technical Reports Server (NTRS)

    Baker, K. B.

    1978-01-01

    The structure of pulsar magnetospheres and the acceleration mechanism for charged particles in the magnetosphere was studied using a pulsar model which required large acceleration of the particles near the surface of the star. A theorem was developed which showed that particle acceleration cannot be expected when the angle between the magnetic field lines and the rotation axis is constant (e.g. radial field lines). If this angle is not constant, however, acceleration must occur. The more realistic model of an axisymmetric neutron star with a strong dipole magnetic field aligned with the rotation axis was investigated. In this case, acceleration occurred at large distances from the surface of the star. The magnitude of the current can be determined using the model presented. In the case of nonaxisymmetric systems, the acceleration is expected to occur nearer to the surface of the star.

  4. 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.

  5. 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).

  6. 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}.

  7. Nonlinear development of strong current-driven instabilities and selective acceleration of ^3He ions

    NASA Astrophysics Data System (ADS)

    Toida, Mieko; Okumura, Hayato

    2003-10-01

    In some solar flares, the abundance of high-energy ^3He ions is extremely increased. As a mechanism for these ^3He rich events, current-driven instabilities are believed to be important. Nonlinear development of the strong current-driven instabilities and associated energy transfer to ^3He ions are studied theoretically and numerically [1]. First, by means of a two-dimensional, electrostatic, particle simulation code, it is demonstrated that ^3He ions are selectively accelerated by fundamental H cyclotron waves with frequencies ω ≃ 2Ω_3He (Ω_3He is the cyclotron frequency of ^3He). Then, from the analysis of the dispersion relation of these waves, it is found that the ω ≃ 2 Ω_ 3He waves have the greatest growth rate, if Te > 10 T_H. Energies of the ^3He ions are also discussed. Theoretical expression for the maximum ^3He energy is presented, which is in good agreement with the simulation results. Based on this theory, it is shown that when the initial electron drift energy is of the order of 10 keV, many ^3He ions can be accelerated to energies of the order of MeV/n. [1] M. Toida and H. Okumura, J. Phys. Soc. Jpn. 72,1098 (2003)

  8. One DOF mechanism for the mechanical harvest of vines in an arbor structure and the validation of the acceleration of grape berry harvesting

    NASA Astrophysics Data System (ADS)

    Penisi, Osvaldo; Bocca, José; Aguilar, Horacio; Bocca, Pedro

    2015-09-01

    In the mechanized harvest of vines, grape berries are detached through the vibration to the structure supporting the clusters. According to the kind of guide selected, the clusters require one or two vibration directions in the structure. For guiding in parral structures, vibration is necessary in two directions or planes: One perpendicular to the other. The guide branches producing the clusters develop in these planes, and the guiding is called H-guiding. Mechanism theory indicates that a mechanism has as many degrees of freedom as its actuators, and an actuator is needed to achieve a certain vibration. Having the smallest number of possible actuators is beneficial in reducing moving parts and achieving more compact and easily controllable mechanisms. In this case, a single degree-of-freedom mechanism is proposed. It is capable of generating vibrations on two planes: One perpendicular to the other. This mechanism is the sum of two link mechanisms on perpendicular planes with a common outlet located at the output rod of the mechanism where the actuator is found. As the distance between the soil and the elements containing the clusters is not constant, a system has been designed to measure the accelerations at the bars and the rocker to validate the acceleration values that detach the grape berries in a prototype in a lab experiment, to ensure that the acceleration needed for pulling the grape berries are produced at any contact point of the bar.

  9. 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.

  10. Development of a GVM-based ion beam energy stabilization system at the Bucharest Van de Graaff FN tandem accelerator

    NASA Astrophysics Data System (ADS)

    Mosu, D. V.; Ghit, D. G.; Dobrescu, S.; Sava, T.; Savu, B.; Naghel, G.; Moisa, D.; Calinescu, I. C.; Dumitru, G.; Mitu, I. O.; Petcu, M.; Cata-Danil, Gh.

    2013-04-01

    This paper presents a new, home-made, GVM (Generating Voltmeter) ion beam energy stabilization system, currently in operation at the Bucharest Tandem Van de Graaff accelerator. The new design combines the signal from the GVM preamplifier with the signal of an original digital reference, in order to obtain an error signal needed by the high-voltage stabilization loop. It is shown that the structure of the employed algorithm provides a high efficiency operation mode for the slow variation of accelerating voltage, with the exception of discharges in the high voltage system. The block structure design, construction features, and tests of this new stabilization system are reported in detail.

  11. Accelerating the development of an AIDS vaccine: the AIDS vaccine for Asia Network (Avan).

    PubMed

    Pitisuttithum, Punnee; Rerks-Ngarm, Supachai; Chiu, Joseph; Kim, Jerome; Benenson, Michael; Kent, Stephen J; Tamashiro, Hiko; Manrique, Amapola; Bernstein, Alan; Goyal, Rajat; Ditangco, Rossana A; Cooper, David A; Osmanov, Saladin; Mathieson, Bonnie; Sandstrom, Eric; Esparza, Jose; Hoff, Rodney; Shao, Yiming

    2011-09-01

    HIV/AIDS is a major public health problem worldwide, especially in developing countries. The development of a safe and effective HIV vaccine is central to stopping the epidemic and would be a great public health tool. The AIDS Vaccine for Asia Network (AVAN) is a group of concerned investigators committed to assisting regional and global HIV vaccine efforts. AVAN's focus on improving the coordination and harmonization of research, ethical reviews, clinical trial capacity, regulatory frameworks, vaccine manufacturing, community participation, and government advocacy could help accelerate HIV vaccine efforts in the region. At a meeting in November 2010, researchers from various countries in Asia presented their progress in HIV vaccine research and development. Six working groups discussed the current status, gaps and methods to strengthen capacity and infrastructure in various areas related to AIDS vaccine research and development. These discussions led to the development of prioritized action plans for the next 5 years. This report describes the gaps and challenges HIV vaccine research faces in the region and recommends improvement and standardization of facilities, and coordination and harmonization of all activities related to AIDS vaccine research and development, including possible technology transfer when a vaccine becomes available.

  12. The stimulation of immune defence accelerates development in the red flour beetle (Tribolium castaneum).

    PubMed

    Roth, O; Kurtz, J

    2008-11-01

    The timing of the transition between life stages is of key importance for an organism. Depending on the environmental conditions, maturing earlier at a smaller size or maturing later at a larger size can be advantageous for fitness. Exposure to parasites and subsequent immune activation may lead to alterations in development. Immune defence often comes at a cost, such as energy drain towards immune function, which is likely to delay development. On the other hand, animals may react to an anticipated risk of infection with a phenotypically plastic shift in life history, which may more likely lead to accelerated development and earlier maturation. We tested these alternatives in the red flour beetle, Tribolium castaneum. Young larvae were exposed to a non-infectious immune challenge with heat-killed bacteria (either Escherichia coli or Bacillus thuringiensis) and they were followed up for their development, survival, adult size and reproduction. We found that animals that had experienced a bacterial challenge developed into adults earlier than sham-treated beetles, while they did not differ significantly in survival or adult size. Beetles exposed to E. coli produced fewer offspring, while exposure to B. thuringiensis did not affect offspring number. Taken together, our results indicate that T. castaneum is able to speed up its development when facing a risk of infection.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Development of the field of structural physiology.

    PubMed

    Fujiyoshi, Yoshinori

    2015-01-01

    Electron crystallography is especially useful for studying the structure and function of membrane proteins - key molecules with important functions in neural and other cells. Electron crystallography is now an established technique for analyzing the structures of membrane proteins in lipid bilayers that closely simulate their natural biological environment. Utilizing cryo-electron microscopes with helium-cooled specimen stages that were developed through a personal motivation to understand the functions of neural systems from a structural point of view, the structures of membrane proteins can be analyzed at a higher than 3 Å resolution. This review covers four objectives. First, I introduce the new research field of structural physiology. Second, I recount some of the struggles involved in developing cryo-electron microscopes. Third, I review the structural and functional analyses of membrane proteins mainly by electron crystallography using cryo-electron microscopes. Finally, I discuss multifunctional channels named "adhennels" based on structures analyzed using electron and X-ray crystallography.

  18. 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.

  19. Regulatory science accelerates the development of biotechnology drugs and vaccines by NIFDC

    PubMed Central

    Liang, Zhenglun; Mao, Qunying; Wang, Yiping; Li, Changgui; Gao, Kai; Wang, Junzhi

    2014-01-01

    The Chinese National Institutes for Food and Drug Control (NIFDC) is the national laboratory responsible for the quality control of pharmaceutical products. In recent years, to ensure the quality of biological products and improve the research and development (R&D) of new biological drugs and vaccines, NIFDC conducted a series of regulatory science studies on key technologies for quality control and evaluation, and established a quality control and evaluation platform for biological drugs and vaccines. These studies accelerated the R&D of the biological drugs and vaccines in China and assured their safety and efficacy. In this paper, NIFDC's duties and achievements in the biological drug and vaccine field are summarized. PMID:26038758

  20. Recent advances in the development of high average power induction accelerators for industrial and environmental applications

    SciTech Connect

    Neau, F.L.

    1994-12-31

    Short-pulse accelerator technology developed during time period from the early 60`s through the late 80`s is now being extended to high average power systems capable of being used in industrial and environmental applications. Processes requiring high dose levels and/or high volume throughput may require systems with beam power levels from several hundreds of kilowatts to megawatts. Processes may include chemical waste mitigation, flue gas cleanup, food pasteurization, and new forms of materials preparation and treatment. This paper will address the present status of high average power systems now in operation that use combinations of semiconductor and saturable core magnetic switches with inductive voltage adders to achieve MeV beams of electrons or x-rays over areas of 10,000 cm{sup 2} or more. Similar high average power technology is also being used below 1 MeV to drive repetitive ion beam sources for treatment of material surfaces.

  1. 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.

  2. 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.

  3. Can Delta-V be Adjusted with Structural and Occupant Restraint Performance to Improve Prediction of Chest Acceleration?

    PubMed Central

    Gabauer, Douglas J.; Gabler, Hampton C.

    2008-01-01

    The purpose of this study is to investigate whether delta-V can be modified with a measure of vehicle structure performance and occupant restraint performance to better predict occupant peak chest acceleration during a frontal crash. A total of 619 full-scale frontal crash tests, with impact speeds ranging from 14 to 42 mph, were analyzed. Multiple linear regression was used to correlate combinations of crash severity, vehicle structure performance, and occupant restraint performance descriptors to the maximum measured crash test dummy chest acceleration. Using an adjusted R2 selection method, the best combination of metrics were selected and then compared to a baseline model that used only delta-V to predict occupant chest kinematics. The combination of delta-V, ridedown efficiency, and the kinetic energy factor was found to provide the best prediction of the occupant chest acceleration. This combination accounted for approximately 4 times the variation in the maximum chest acceleration when compared to a model based solely on vehicle delta-V. PMID:19026233

  4. 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

  5. Laser Acceleration in Vacuum and Gases with Capillary Waveguide

    SciTech Connect

    Xie, Ming

    1999-02-01

    A unified framework is developed to overcome all three major limitations on acceleration and distance and hence on the feasibility of two classes of laser acceleration. The three limitations are due to laser diffraction, acceleration phase slippage, and structure damage by high power laser if solid-state optical waveguide is used. The two classes of laser acceleration are direct-field acceleration and ponderomotive-driven acceleration. Thus this letter and its companion [1] provide solutions that are crucial to all mainstream approaches for laser acceleration, either in vacuum, gases or plasmas.

  6. Automated small‐scale protein purification and analysis for accelerated development of protein therapeutics

    PubMed Central

    LeSaout, Xavier; Costioli, Matteo; Jordan, Lynn; Lambert, Jeremy; Beighley, Ross; Provencher, Laurel; McGuire, Kevin; Verlinden, Nico; Barry, Andrew

    2015-01-01

    Small‐scale protein purification presents opportunities for accelerated process development of biotherapeutic molecules. Miniaturization of purification conditions reduces time and allows for parallel processing of samples, thus offering increased statistical significance and greater breadth of variables. The ability of the miniaturized platform to be predictive of larger scale purification schemes is of critical importance. The PerkinElmer JANUS BioTx Pro and Pro‐Plus workstations were developed as intuitive, flexible, and automated devices capable of performing parallel small‐scale analytical protein purification. Preprogrammed methods automate a variety of commercially available ion exchange and affinity chromatography solutions, including miniaturized chromatography columns, resin‐packed pipette tips, and resin‐filled microtiter vacuum filtration plates. Here, we present a comparison of microscale chromatography versus standard fast protein LC (FPLC) methods for process optimization. In this study, we evaluated the capabilities of the JANUS BioTx Pro‐Plus robotic platform for miniaturized chromatographic purification of proteins with the GE ӒKTA Express system. We were able to demonstrate predictive analysis similar to that of larger scale purification platforms, while offering advantages in speed and number of samples processed. This approach is predictive of scale‐up conditions, resulting in shorter biotherapeutic development cycles and less consumed material than traditional FPLC methods, thus reducing time‐to‐market from discovery to manufacturing.

  7. 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.

  8. Effect of Hot Coiling Under Accelerated Cooling on Development of Non-equiaxed Ferrite in Low Carbon Steel

    NASA Astrophysics Data System (ADS)

    Lanjewar, H. A.; Tripathi, Pranavkumar

    2016-06-01

    Strengthening mechanisms dominant in non-equiaxed ferrite structures are not so familiar and well measured. In present study, non-equiaxed ferritic structures were generated and perceived to be strengthened by grain/crystal refinement, presence of varying substructures, solid solution strengthening, and textural hardening. A Nb-V microalloyed steel was modeled under various accelerated cooling and coiling temperature conditions in a thermo-mechanical simulator. Decrease in coiling temperature in conjunction with accelerated cooling resulted in non-equiaxed ferrite structures with array of phase morphologies. Intermediate transformation conditions produced increase in strength concurrent with observed smallness in crystallite size and high amount of microstrain in the matrix phase indicative of high dislocation densities and crystal imperfections. Increase in strength is partially attributed to solid solution and texture hardening owing to increase in (111) pole intensity in structure.

  9. Molecule-optimized basis sets and Hamiltonians for accelerated electronic structure calculations of atoms and molecules.

    PubMed

    Gidofalvi, Gergely; Mazziotti, David A

    2014-01-16

    Molecule-optimized basis sets, based on approximate natural orbitals, are developed for accelerating the convergence of quantum calculations with strongly correlated (multireferenced) electrons. We use a low-cost approximate solution of the anti-Hermitian contracted Schrödinger equation (ACSE) for the one- and two-electron reduced density matrices (RDMs) to generate an approximate set of natural orbitals for strongly correlated quantum systems. The natural-orbital basis set is truncated to generate a molecule-optimized basis set whose rank matches that of a standard correlation-consistent basis set optimized for the atoms. We show that basis-set truncation by approximate natural orbitals can be viewed as a one-electron unitary transformation of the Hamiltonian operator and suggest an extension of approximate natural-orbital truncations through two-electron unitary transformations of the Hamiltonian operator, such as those employed in the solution of the ACSE. The molecule-optimized basis set from the ACSE improves the accuracy of the equivalent standard atom-optimized basis set at little additional computational cost. We illustrate the method with the potential energy curves of hydrogen fluoride and diatomic nitrogen. Relative to the hydrogen fluoride potential energy curve from the ACSE in a polarized triple-ζ basis set, the ACSE curve in a molecule-optimized basis set, equivalent in size to a polarized double-ζ basis, has a nonparallelity error of 0.0154 au, which is significantly better than the nonparallelity error of 0.0252 au from the polarized double-ζ basis set.

  10. 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

  11. Acceleration of non-relativistic electrons at a dielectric grating structure: Status report

    SciTech Connect

    Breuer, John; Hommelhoff, Peter

    2012-12-21

    We report on an experiment aiming at a proof-of-concept of a non-relativistic direct laser accelerator. The system is based on a fused-silica transmission grating illuminated by Titanium:sapphire femtosecond pulses in order to excite evanescent spatial modes, which propagate synchronously with 28 keV electrons originating from an electron column of a scanning electron microscope. The grating period is 750 nm, and we use the third spatial harmonic to continuously accelerate the non-relativistic electrons. With a laser pulse energy of about 150 nJ numerical simulations show expected accelerating gradients of up to 60 MeV/m and an energy gain of around 300 eV at a distance of 100 nm away from the grating surface. The current status of the experiment is reported.

  12. 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

  13. Structural basis of Ornithine Decarboxylase inactivation and accelerated degradation by polyamine sensor Antizyme1

    PubMed Central

    Wu, Donghui; Kaan, Hung Yi Kristal; Zheng, Xiaoxia; Tang, Xuhua; He, Yang; Vanessa Tan, Qianmin; Zhang, Neng; Song, Haiwei

    2015-01-01

    Ornithine decarboxylase (ODC) catalyzes the first and rate-limiting step of polyamine biosynthesis in humans. Polyamines are essential for cell proliferation and are implicated in cellular processes, ranging from DNA replication to apoptosis. Excessive accumulation of polyamines has a cytotoxic effect on cells and elevated level of ODC activity is associated with cancer development. To maintain normal cellular proliferation, regulation of polyamine synthesis is imposed by Antizyme1 (AZ1). The expression of AZ1 is induced by a ribosomal frameshifting mechanism in response to increased intracellular polyamines. AZ1 regulates polyamine homeostasis by inactivating ODC activity and enhancing its degradation. Here, we report the structure of human ODC in complex with N-terminally truncated AZ1 (cAZ1). The structure shows cAZ1 binding to ODC, which occludes the binding of a second molecule of ODC to form the active homodimer. Consequently, the substrate binding site is disrupted and ODC is inactivated. Structural comparison shows that the binding of cAZ1 to ODC causes a global conformational change of ODC and renders its C-terminal region flexible, therefore exposing this region for degradation by the 26S proteasome. Our structure provides the molecular basis for the inactivation of ODC by AZ1 and sheds light on how AZ1 promotes its degradation. PMID:26443277

  14. High Power Proton Accelerator Development at KAERI and its Vacuum System

    NASA Astrophysics Data System (ADS)

    Choi, Byung-Ho; Park, Mi Young; Kim, Kui Young; Kim, Kye Ryung; Kim, Jun Yeon; Cho, Yong-Sub

    The Proton Engineering Frontier Project (PEFP), approved and launched by the Korean government in July 2002, includes a 100 MeV proton linear accelerator (linac) development and programs for its utilization and application. The main goals in the first phase of the project, spanning from 2002 to 2005, were the design of a 100 MeV proton linac and the development of a 20 MeV linac consisting of a 50 keV proton injector, a 3 MeV radio frequency quadrupole (RFQ), and a 20 MeV drift tube linac (DTL). The 50 keV injector and 3 MeV RFQ have been installed and tested, and the 20 MeV DTL is being assembled, tuned and under a beam test. At the same time, the utilization programs using the proton beam have been planned, and some are now under way. The vacuum system of the 20 MeV proton linac and its related issues, especially in operation with a high duty, are discussed in detail.

  15. Chronic exogenous kisspeptin administration accelerates gonadal development in basses of the genus Morone.

    PubMed

    Beck, Benjamin H; Fuller, S Adam; Peatman, Eric; McEntire, Matthew E; Darwish, Ahmed; Freeman, Donald W

    2012-07-01

    The present study assesses the effects of chronic administration of peptides to fish, termed kisspeptins, which are the products of the KISS1 and KISS2 genes, and have been shown to control the development of puberty in animals. Using ecologically and commercially important species (white bass, Morone chrysops, striped bass, Morone saxatilis, and their hybrid) as comparative models, we determined that repeated bi-weekly injections (over 7 weeks) differentially accelerate puberty, as evidenced by increases in the prevalence of spermatozoa in the testes of juvenile fish. Moreover, in sexually mature fish, kisspeptin treatment led to increased gonad weight, gonadosomatic index, and spermatocrit in some white and striped bass. Additionally, mature white bass treated with kisspeptins showed an advancement in oocyte development as determined by histological examination. These gonadal changes occurred in the absence of any photothermal manipulation or hormone injections. To date, this is the first description of kisspeptin-mediated pubertal initiation in fish, and the first evidence that kisspeptins could modulate gonad maturation. Although it remains to be determined how kisspeptins may best be utilized in practice, our findings are a basis for future studies to characterize the molecular underpinnings of the KISS system in various fish species. PMID:22497780

  16. Crizotinib: from discovery to accelerated development to front-line treatment.

    PubMed

    Blackhall, F; Cappuzzo, F

    2016-09-01

    Non-small-cell lung cancer (NSCLC) is associated with a poor prognosis and low survival rates, providing a strong rationale for the development of new treatment options. The discovery of ALK gene rearrangements in a subset of NSCLC specimens and the identification and development of the first-in-class ALK inhibitor crizotinib provided a personalised treatment option for patients with advanced ALK-positive NSCLC. Crizotinib demonstrated rapid and durable responses in advanced ALK-positive NSCLC patients in phase I and II studies, leading to accelerated FDA approval. Subsequent evaluation in phase III studies showed that crizotinib improved progression-free survival compared with platinum-based doublet chemotherapy in previously untreated patients and compared with pemetrexed or docetaxel in previously treated patients. Crizotinib was shown to have an acceptable safety profile and also to improve quality of life and symptom scores. Overall, crizotinib has been shown to provide a valuable first- and second-line treatment option and is now the first-line standard of care for patients with advanced ALK-positive NSCLC. PMID:27573754

  17. 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. PMID:25171521

  18. Orthodontic force accelerates dentine mineralization during tooth development in juvenile rats.

    PubMed

    Kong, Xiangwei; Cao, Meng; Ye, Ruidong; Ding, Yin

    2010-08-01

    Malocclusion, the improper positioning of the teeth and jaws, is among the most important global oral health burdens. People with malocclusion may require orthodontic treatment to correct the problem. Orthodontic treatment is a way of straightening or moving teeth, to improve the appearance of the teeth and how they work. It is generally best carried out in children aged 9 to 12 years, whose teeth are mainly young permanent teeth with incomplete root formation. However, the relationship between orthodontic force and tooth development has not been fully understood. In this study, we sought to investigate the effects of orthodontic force on dentine formation and mineralization during the development of young permanent teeth. Standardized orthodontic tooth movement was performed with the orthodontic appliance in five-week-old rats. To obtain longitudinal assessment of dentine formation, tetracycline was administered on the operation day and 1, 3, 7, 14 or 21 days afterward. We found that the distance between two tetracycline stripes, which indicates the amount of dentine formation during orthodontic treatment, increased with time. Importantly, no significant difference was detected in dentine formation between treated and control rats. In contrast, immunohistochemical analysis showed that the expression of dentin sialoprotein, a marker of odontoblast differentiation and mineral apposition, was significantly elevated in crown and root dentine after orthodontic treatment. In conclusion, orthodontic treatment does not affect the dentine formation of young permanent teeth, but it promotes the activation of odontoblasts and accelerates the dentine mineralization. These results suggest the safety of early orthodontic treatment.

  19. 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.

  20. Promoting Student Development through Intentionally Structured Groups.

    ERIC Educational Resources Information Center

    Winston, Roger B., Jr.; And Others

    Very little has been written in the area of the application of structured or planned groups in college settings, particularly in making a direct connection between theories of college-student development and the use of groups to facilitate and encourage that development. Information is provided in this book for all in higher education who are…

  1. Early natural stimulation through environmental enrichment accelerates neuronal development in the mouse dentate gyrus.

    PubMed

    Liu, Na; He, Shan; Yu, Xiang

    2012-01-01

    The dentate gyrus is the primary afferent into the hippocampal formation, with important functions in learning and memory. Granule cells, the principle neuronal type in the dentate gyrus, are mostly formed postnatally, in a process that continues into adulthood. External stimuli, including environmental enrichment, voluntary exercise and learning, have been shown to significantly accelerate the generation and maturation of dentate granule cells in adult rodents. Whether, and to what extent, such environmental stimuli regulate the development and maturation of dentate granule cells during early postnatal development is largely unknown. Furthermore, whether natural stimuli affect the synaptic properties of granule cells had been investigated neither in newborn neurons of the adult nor during early development. To examine the effect of natural sensory stimulation on the dentate gyrus, we reared newborn mice in an enriched environment (EE). Using immunohistochemistry, we showed that dentate granule cells from EE-reared mice exhibited earlier morphological maturation, manifested as faster peaking of doublecortin expression and elevated expression of mature neuronal markers (including NeuN, calbindin and MAP2) at the end of the second postnatal week. Also at the end of the second postnatal week, we found increased density of dendritic spines across the entire dentate gyrus, together with elevated levels of postsynaptic scaffold (post-synaptic density 95) and receptor proteins (GluR2 and GABA(A)Rγ2) of excitatory and inhibitory synapses. Furthermore, dentate granule cells of P14 EE-reared mice had lower input resistances and increased glutamatergic and GABAergic synaptic inputs. Together, our results demonstrate that EE-rearing promotes morphological and electrophysiological maturation of dentate granule cells, underscoring the importance of natural environmental stimulation on development of the dentate gyrus.

  2. Development of a two-beam high-current ion accelerator based on Doppler effect. Final report (1994)

    SciTech Connect

    Ivanov, B.I.; Yegorov, A.M.

    1995-03-01

    This Final Report presents the results of work accomplished in accordance with the Scope of Work to the Purchase Order No 4596310. The amount of works includes the following items: 1. Start of the manufacture of the Experimental Accelerating Stand (EAS)-the section for proton acceleration from 5 MeV to 8 MeV, in which RF fields are excited by an electron beam at the anomalous Doppler effect. 2. Theoretical investigation and computer simulation of field excitation and ion acceleration in the EAS. Under item 1, the EAS manufacturing is begun. To present time, a pedestal for the EAS and a stainless steel vacuum chamber for RF resonator are made (length of the chamber is about 180 cm, diameter is about 40 cm). Besides, parts of the EAS resonator with the acceleration structure are manufactured, and its assembly is begun. Under item 2, it is realized three works: calculation of increment and frequency shift of the EAS resonator excited by electron beam, calculation of the solenoid for creation of magnetic field with required spatial distribution, and theoretical investigation and computer simulation of ion acceleration in the EAS. 14 figs., 16 refs.

  3. 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.

  4. 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.

  5. 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.

  6. Development and Study of NB3SN Strands and Cables for High-Field Accelerator Magnets

    NASA Astrophysics Data System (ADS)

    Barzi, E.; Andreev, N.; Bossert, M.; Kashikhin, V. V.; Turrioni, D.; Yamada, R.; Zlobin, A. V.

    2010-04-01

    The high performance Nb3Sn strand produced by Oxford Superconducting Technology (OST) with the Restack Rod Process (RRP) and a 127 restack design is the baseline conductor presently used in the Fermilab's accelerator magnet R&D program. The original RRP-127 design was further improved in stability by increasing the Cu thickness between subelements after proving the effectiveness of this method in reducing subelement merging [1-3]. A number of RRP-127 billets of various cross sections (RRP-102/127, RRP-108/127 and RRP-114/127) were produced to optimize the design with respect to strand plastic deformation during cabling. The behavior of these new strands was studied using virgin and deformed strand samples, and compared with that of the RRP-54/61 stack design. A Rutherford cable made of 0.7 mm strands was also produced to be used in high field quadrupoles. This paper describes the RRP-127 strand development, and results of strand and cable analyses.

  7. 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.

  8. PET and SPECT Imaging for the Acceleration of Anti-Cancer Drug Development.

    PubMed

    Hillyar, Christopher R T; Knight, James C; Vallis, Katherine A; Cornelissen, Bart

    2015-01-01

    Lead-compound optimization is an iterative process in the cancer drug development pipeline, in which small molecule inhibitors or biological compounds that are selected for their ability to bind specific targets are synthesised, tested and optimised. This process can be accelerated significantly using molecular imaging with nuclear medicine techniques, which aim to monitor the biodistribution and pharmacokinetics of radiolabelled versions of compounds. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can be used to quantify fourdimensional (temporal and spatial) clinically relevant information, to demonstrate tumor uptake of, and monitor the response to treatment with lead-compounds. This review discusses the pre-clinical and clinical value of the information provided by nuclear medicine imaging compared to the histological analysis of biopsied tissue samples. Also, the role of nuclear medicine imaging is discussed with regard to the assessment of the treatment response, radiotracer biodistribution, tumor accumulation, toxicity, and pharmacokinetic parameters, with mention of microdosing studies, pre-targeting strategies, and pharmacokinetic modelling. PMID:25901527

  9. 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

  10. 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.

  11. Development and applications of infrared structural biology

    NASA Astrophysics Data System (ADS)

    Kang, Zhouyang

    Aspartic acid (Asp), Glutamic acid (Glu) and Tyrosine (Tyr) often play critical roles at the active sites of proteins. Probing the structural dynamics of functionally important Asp/Glu and Tyr provides crucial information for protein functionality. Time-resolved infrared structural biology offers strong advantages for its high structural sensitivity and broad dynamic range (picosecond to kilosecond). In order to connect the vibrational frequencies to specific structures of COO- groups and phenolic --OH groups, such as the number, type, and geometry of hydrogen bond interactions, we develop two sets of vibrational structural markers (VSM), built on the symmetric and asymmetric stretching frequencies for COO- and C-O stretching and C-O-H bending frequencies for phenolic --OH. Extensive quantum physics (density functional theory) based computational studies, combined with site-specific isotope labeling as well as site-directed mutagenesis, and experimental FTIR data on Asp/Glu in proteins, are used to establish a unique correlation between the vibrations and multiple types of hydrogen bonding interactions. Development of those vibrational structural markers significantly enhances the power of time-resolved infrared structural biology for the study of functionally important structural dynamics of COO- from Asp/Glu and phenolic --OH from Tyr residues in proteins, including rhodopsin for biological signaling, bacteriorhodopsin and PYP for proton transfer, photosystem II for energy transformation, and HIV protease for enzymatic catalysis. Furthermore, this approach can be adopted in the future development of vibrational structural markers for other functionally important amino acid residues in proteins, such as arginine (Arg), histidine (His), and serine (Ser).

  12. The development of algorithms for parallel knowledge discovery using graphics accelerators

    NASA Astrophysics Data System (ADS)

    Zieliński, Paweł; Mulawka, Jan

    2011-10-01

    The paper broaches topics of selected knowledge discovery algorithms. Different implementations have been verified on parallel platforms, including graphics accelerators using CUDA technology, multi-core microprocessors using OpenMP and many graphics accelerators. Results of investigations have been compared in terms of performance and scalability. Different types of data representation were also tested. The possibilities of both platforms, using the classification algorithms: the k-nearest neighbors, support vector machines and logistic regression are discussed.

  13. 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.

  14. Muscle contributions to centre of mass acceleration during turning gait in typically developing children: A simulation study.

    PubMed

    Dixon, Philippe C; Jansen, Karen; Jonkers, Ilse; Stebbins, Julie; Theologis, Tim; Zavatsky, Amy B

    2015-12-16

    Turning while walking requires substantial joint kinematic and kinetic adaptations compared to straight walking in order to redirect the body centre of mass (COM) towards the new walking direction. The role of muscles and external forces in controlling and redirecting the COM during turning remains unclear. The aim of this study was to compare the contributors to COM medio-lateral acceleration during 90° pre-planned turns about the inside limb (spin) and straight walking in typically developing children. Simulations of straight walking and turning gait based on experimental motion data were implemented in OpenSim. The contributors to COM global medio-lateral acceleration during the approach (outside limb) and turn (inside limb) stance phase were quantified via an induced acceleration analysis. Changes in medio-lateral COM acceleration occurred during both turning phases, compared to straight walking (p<0.001). During the approach, outside limb plantarflexors (soleus and medial gastrocnemius) contribution to lateral (away from the turn side) COM acceleration was reduced (p<0.001), whereas during the turn, inside limb plantarflexors (soleus and gastrocnemii) contribution to lateral acceleration (towards the turn side) increased (p≤0.013) and abductor (gluteus medius and minimus) contribution medially decreased (p<0.001), compared to straight walking, together helping accelerate the COM towards the new walking direction. Knowledge of the changes in muscle contributions required to modulate the COM position during turning improves our understanding of the control mechanisms of gait and may be used clinically to guide the management of gait disorders in populations with restricted gait ability.

  15. Development of the field of structural physiology

    PubMed Central

    FUJIYOSHI, Yoshinori

    2015-01-01

    Electron crystallography is especially useful for studying the structure and function of membrane proteins — key molecules with important functions in neural and other cells. Electron crystallography is now an established technique for analyzing the structures of membrane proteins in lipid bilayers that closely simulate their natural biological environment. Utilizing cryo-electron microscopes with helium-cooled specimen stages that were developed through a personal motivation to understand the functions of neural systems from a structural point of view, the structures of membrane proteins can be analyzed at a higher than 3 Å resolution. This review covers four objectives. First, I introduce the new research field of structural physiology. Second, I recount some of the struggles involved in developing cryo-electron microscopes. Third, I review the structural and functional analyses of membrane proteins mainly by electron crystallography using cryo-electron microscopes. Finally, I discuss multifunctional channels named “adhennels” based on structures analyzed using electron and X-ray crystallography. PMID:26560835

  16. 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.

  17. 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

  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. Recent developments in the application of rf superconductivity to 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.

    1991-12-31

    A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high- brightness ion beams. Since the last workshop, considerable progress has been made both experimentally and theoretically toward this application. Recent tests of niobium resonators for ion acceleration have yielded average accelerating gradients as high as 18 MV/m. In an experiment with a radio-frequency quadrupole geometry, niobium was found to sustain cw peak surface electric fields as high as 128 MV/m over large (10 cm{sup 2}) surface areas. Theoretical studies of beam impingement and cumulative beam breakup have also yielded encouraging results. Consequently, a section of superconducting resonators and focusing elements has been designed for tests with high-current deuteron beams. In addition, considerable data pertaining to the rf properties of high-{Tc} superconductors has been collected at rf-field amplitudes and frequencies of interest in connection with accelerator operation. This paper summarizes the recent progress and identifies current and future work in the areas of accelerator technology and superconducting materials which will build upon it.

  20. Recent developments in the application of rf superconductivity to 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.

    1991-01-01

    A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high- brightness ion beams. Since the last workshop, considerable progress has been made both experimentally and theoretically toward this application. Recent tests of niobium resonators for ion acceleration have yielded average accelerating gradients as high as 18 MV/m. In an experiment with a radio-frequency quadrupole geometry, niobium was found to sustain cw peak surface electric fields as high as 128 MV/m over large (10 cm{sup 2}) surface areas. Theoretical studies of beam impingement and cumulative beam breakup have also yielded encouraging results. Consequently, a section of superconducting resonators and focusing elements has been designed for tests with high-current deuteron beams. In addition, considerable data pertaining to the rf properties of high-{Tc} superconductors has been collected at rf-field amplitudes and frequencies of interest in connection with accelerator operation. This paper summarizes the recent progress and identifies current and future work in the areas of accelerator technology and superconducting materials which will build upon it.