Score Normalization for Keyword Search

DTIC Science & Technology

2016-06-23

Anahtar Sözcük Arama için Skor Düzgeleme Score Normalization for Keyword Search Leda Sarı, Murat Saraçlar Elektrik ve Elektronik Mühendisliği Bölümü...skor düzgeleme. Abstract—In this work, keyword search (KWS) is based on a symbolic index that uses posteriorgram representation of the speech data...For each query, sum-to-one normalization or keyword specific thresholding is applied to the search results. The effect of these methods on the proposed

VizieR Online Data Catalog: Luminous persistent sources in nearby galaxies search (Ofek, 2017)

NASA Astrophysics Data System (ADS)

Ofek, E. O.

2018-04-01

I compiled a catalog of nearby galaxies within 108Mpc. The catalog is based on combining the HyperLEDA galaxies (Paturel+ 2003, VII/238 ; Makarov+ 2014A&A...570A..13M) with the NASA Extragalactic Database (NED) redshifts, and the Sloan Digital Sky Survey (SDSS; York+ 2000AJ....120.1579Y ; see V/147) galaxies with known redshifts. Both catalogs are restricted to the FIRST radio survey footprint (Becker+ 1995ApJ...450..559B ; see VIII/92). (1 data file).

VizieR Online Data Catalog: Galaxies in Hercules-Bootes region (Karachentsev+, 2017)

NASA Astrophysics Data System (ADS)

Karachentsev, I. D.; Kashibadze, O. G.; Karachentseva, V. E.

2017-04-01

The table contains original observational data on 412 galaxies in the Hercules-Bootes region with radial velocities of VLG<2500km/s. The main source of data is the NASA Extragalactic Database (NED) with additions from the HyperLEDA Database. Each object with a radial velocity estimate was visually inspected, and a large number of false "galaxies" with radial velocities of around zero was discarded. For many galaxies, we have refined the morphological types and integral B-magnitudes. The resulting sample includes 181 galaxies with individual distance estimates. (1 data file).

Implications for the Origin of Early-type Dwarf Galaxies: A Detailed Look at the Isolated Rotating Early-type Dwarf Galaxy LEDA 2108986 (CG 611), Ramifications for the Fundamental Plane’s {S}_{K}^{2} Kinematic Scaling, and the Spin-Ellipticity Diagram

NASA Astrophysics Data System (ADS)

Graham, Alister W.; Janz, Joachim; Penny, Samantha J.; Chilingarian, Igor V.; Ciambur, Bogdan C.; Forbes, Duncan A.; Davies, Roger L.

2017-05-01

Selected from a sample of nine, isolated, dwarf early-type galaxies (ETGs) with the same range of kinematic properties as dwarf ETGs in clusters, we use LEDA 2108986 (CG 611) to address the nature versus nurture debate regarding the formation of dwarf ETGs. The presence of faint disk structures and rotation within some cluster dwarf ETGs has often been heralded as evidence that they were once late-type spiral or dwarf irregular galaxies prior to experiencing a cluster-induced transformation into an ETG. However, CG 611 also contains significant stellar rotation (≈20 km s-1) over its inner half-light radius ({R}{{e},{maj}}=0.71 kpc), and its stellar structure and kinematics resemble those of cluster ETGs. In addition to hosting a faint young nuclear spiral within a possible intermediate-scale stellar disk, CG 611 has accreted an intermediate-scale, counter-rotating gas disk. It is therefore apparent that dwarf ETGs can be built by accretion events, as opposed to disk-stripping scenarios. We go on to discuss how both dwarf and ordinary ETGs with intermediate-scale disks, whether under (de)construction or not, are not fully represented by the kinematic scaling {S}0.5=\\sqrt{0.5 {V}{rot}2+{σ }2}, and we also introduce a modified spin-ellipticity diagram λ (R)-ɛ (R) with the potential to track galaxies with such disks.

MASTER-SAAO: contradictory SN and flaring OT

NASA Astrophysics Data System (ADS)

Balanutsa, P.; Lipunov, V.; Buckley, D.; Gorbovskoy, E.; Tiurina, N.; Kuznetsov, A.; Kornilov, V.; Gress, O.; Pogrosheva, T.; Shumkov, V.; Vladimirov, V.; Vlasenko, D.; Kuvshinov, D.; Gabovich, A.

2017-07-01

MASTER-SAAO auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 03h 42m 50.70s , -01d 52m 28s.7 on 2017-07-01.1753UT with unfiltered (6 images), that contradicts to Ia type detected in ATEL #10240 , ATEL #10225 for ATLAS17dcl ( http://www.supernova.thistlethwaites.com/sn2017/sndate.html ). It is in 8.4"W,20"S of PGC135685 with Btc=15.13, Vgsr=2773 http://leda.univ-lyon1.fr/ledacat.cgi?PGC135685 Spectral observations are required.

Nonablative skin rejuvenation devices and the role of heat shock protein 70: results of a human skin explant model

NASA Astrophysics Data System (ADS)

Helbig, Doris; Moebius, Anne; Simon, Jan C.; Paasch, Uwe

2010-05-01

Nonablative thermal laser therapy with a 1540-nm laser induces controlled, spatially determined thermal damage, allowing subsequent collagen remodeling while preserving the epidermis. A photorejuvenation effect using nonthermal nonablative stimulation of cells with low energy and narrow band light has been termed photomodulation. Light emitting diodes (LEDs) are narrow band emitters that lead to photomodulation via stimulation of mitochondrial cell organelles. In a previous study, we demonstrated in a human skin explant model that heat shock protein 70 (HSP70) plays a pivotal role in the initiation of skin remodeling after ablative fractional photothermolysis. To test its importance in nonablative laser therapy and photomodulation, the spatio-temporal expression of HSP70 is investigated in response to a 1540-nm laser treatment and six different LED therapies. An Er:glass laser is used with a 1-Hz repetition rate, 30-J/cm2 fluence, and a hand piece with a 2-mm spot size. Nonthermal nonablative treatment is performed using two LED (LEDA SCR red light: 635 nm, 40 to 120 W/cm2, 40 to 120 J/cm2 LEDA SCR yellow light: 585 nm, 16 to 35 W/cm2, 20 to 100 J/cm2 spot size 16×10 cm). Immediate responses as well as responses 1, 3, or 7 days postprocedure are studied; untreated skin explants serve as control. Immunohistochemical investigation (HSP70) is performed in all native, nontreated, and Er:glass laser- or LED-treated samples (n=175). Nonablative laser therapy leads to a clear time-dependent induction of epidermally expressed HSP70, peaking between one to three days post-treatment. In contrast, none of the various LED treatments up-regulated the HSP70 expression in our skin explant model. HSP70 is up-regulated by nonablative but thermal laser devices, but does not seem to play a significant role in the induction of skin remodeling induced by photomodulation. The maximum of HSP70 expression is reached later after Er:glass laser intervention compared to ablative fractional (AFP) treatment.

A traveling-wave forward coupler design for a new accelerating mode in a silicon woodpile accelerator

DOE PAGES

Wu, Ziran; Lee, Chunghun H.; Wootton, Kent P.; ...

2016-03-01

Silicon woodpile photonic crystals provide a base structure that can be used to build a three-dimensional dielectric waveguide system for high-gradient laser driven acceleration. A new woodpile waveguide design that hosts a phase synchronous, centrally confined accelerating mode is proposed. Comparing with previously discovered silicon woodpile accelerating modes, this mode shows advantages in terms of better electron beam loading and higher achievable acceleration gradient. Several traveling-wave coupler design schemes developed for multi-cell RF cavity accelerators are adapted to the woodpile power coupler design for this new accelerating mode. Design of a forward coupled, highly efficient silicon woodpile accelerator is achieved.more » Simulation shows high efficiency of over 75% of the drive laser power coupled to this fundamental accelerating mode, with less than 15% backward wave scattering. The estimated acceleration gradient, when the coupler structure is driven at the damage threshold fluence of silicon at its operating 1.506 μm wavelength, can reach 185 MV/m. Lastly, a 17-layer woodpile waveguide structure was successfully fabricated, and the measured bandgap is in excellent agreement with simulation.« less

A traveling-wave forward coupler design for a new accelerating mode in a silicon woodpile accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Ziran; Lee, Chunghun H.; Wootton, Kent P.

Silicon woodpile photonic crystals provide a base structure that can be used to build a three-dimensional dielectric waveguide system for high-gradient laser driven acceleration. A new woodpile waveguide design that hosts a phase synchronous, centrally confined accelerating mode is proposed. Comparing with previously discovered silicon woodpile accelerating modes, this mode shows advantages in terms of better electron beam loading and higher achievable acceleration gradient. Several traveling-wave coupler design schemes developed for multi-cell RF cavity accelerators are adapted to the woodpile power coupler design for this new accelerating mode. Design of a forward coupled, highly efficient silicon woodpile accelerator is achieved.more » Simulation shows high efficiency of over 75% of the drive laser power coupled to this fundamental accelerating mode, with less than 15% backward wave scattering. The estimated acceleration gradient, when the coupler structure is driven at the damage threshold fluence of silicon at its operating 1.506 μm wavelength, can reach 185 MV/m. Lastly, a 17-layer woodpile waveguide structure was successfully fabricated, and the measured bandgap is in excellent agreement with simulation.« less

Lightcurves of nine asteroids, with pole and sense of rotation of 42 Isis

NASA Astrophysics Data System (ADS)

Denchev, P.; Magnusson, P.; Donchev, Z.

1998-02-01

The results of photometric observations of 9 asteroids collected from 1991 to 1997 are presented. The observations have been conducted at Belogradchik and Rozhen observatories, Bulgaria. For 42 Isis a spin pole determination has been performed: we derive a retrograde sense of rotation, a sidereal period of 0.5665417 ± 0.0000005 days and two solutions for the spin vector: ( P1: λ0 = 288° ± 5°, β0 = -16° ± 2°; P2: λ0 = 117° ± 8°, β0 = -5° ± 4°). The rotational period of 266 Aline is estimated to be 12.3±0.1 h. Composite lightcurves have been obtained for four objects (21 Lutetia, 24 Themis, 42 Isis and 266 Aline). Other lightcurves have been obtained for the asteroids 27 Euterpe, 38 Leda, 70 Panopaea, 173 Ino and 218 Bianca.

A systematic FPGA acceleration design for applications based on convolutional neural networks

NASA Astrophysics Data System (ADS)

Dong, Hao; Jiang, Li; Li, Tianjian; Liang, Xiaoyao

2018-04-01

Most FPGA accelerators for convolutional neural network are designed to optimize the inner acceleration and are ignored of the optimization for the data path between the inner accelerator and the outer system. This could lead to poor performance in applications like real time video object detection. We propose a brand new systematic FPFA acceleration design to solve this problem. This design takes the data path optimization between the inner accelerator and the outer system into consideration and optimizes the data path using techniques like hardware format transformation, frame compression. It also takes fixed-point, new pipeline technique to optimize the inner accelerator. All these make the final system's performance very good, reaching about 10 times the performance comparing with the original system.

The Spallation Neutron Source accelerator system design

NASA Astrophysics Data System (ADS)

Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

2014-11-01

The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

Design, Construction, and Test of a 473 MHZ Four - Cavity Rfq.

NASA Astrophysics Data System (ADS)

Kazimi, Reza

1992-01-01

An RFQ accelerator using the new four-rod cavity design has been fabricated and successfully tested at Texas Accelerator Center. The RFQ is designed to accelerate a 10 mA H^- ion beam from 30 keV to 500 keV with the operating frequency of 473 MHz. This new type of RFQ structure not only promises simplicity of design, construction, and operation, but also can be manufactured to operate at higher frequencies than previously achieved by other four-rod type RFQs. Combination of simplicity and compactness due to higher operating frequencies (400 to 500 MHz) makes the design desirable for injector of proton accelerators, medical linear accelerators, and variety of other applications. This dissertation presents the steps I went through in inventing, developing, and experimentally testing this new RFQ design. First an introduction to accelerators is given, and the basic accelerator physics terminologies are defined. The principles of operations of the RFQs are described, and the theory behind new type of RFQ structure is explained. Then the beam dynamics and cavity design of the RFQ are presented. Finally, the mechanical design and construction procedure are discussed, and experimental results of rf tests and actual H ^- beam test are given.

BBU design of linear induction accelerator cells for radiography application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shang, C.C.; Chen, Y.J.; Gaporaso, G.J.

1997-05-06

There is an ongoing effort to develop accelerating modules for high-current electron accelerators for advanced radiography application. Accelerating modules with low beam-cavity coupling impedances along with gap designs with acceptable field stresses comprise a set of fundamental design criteria. We examine improved cell designs which have been developed for accelerator application in several radiographic operating regimes. We evaluate interaction impedances, analyze the effects of beam structure coupling on beam dynamics (beam break-up instability and corkscrew motion). We also provide estimates of coupling through interesting new high-gradient insulators and evaluate their potential future application in induction cells.

Linear induction accelerators made from pulse-line cavities with external pulse injection.

PubMed

Smith, I

1979-06-01

Two types of linear induction accelerator have been reported previously. In one, unidirectional voltage pulses are generated outside the accelerator and injected into the accelerator cavity modules, which contain ferromagnetic material to reduce energy losses in the form of currents induced, in parallel with the beam, in the cavity structure. In the other type, the accelerator cavity modules are themselves pulse-forming lines with energy storage and switches; parallel current losses are made zero by the use of circuits that generate bidirectional acceleration waveforms with a zero voltage-time integral. In a third type of design described here, the cavities are externally driven, and 100% efficient coupling of energy to the beam is obtained by designing the external pulse generators to produce bidirectional voltage waveforms with zero voltage-time integral. A design for such a pulse generator is described that is itself one hundred percent efficient and which is well suited to existing pulse power techniques. Two accelerator cavity designs are described that can couple the pulse from such a generator to the beam; one of these designs provides voltage doubling. Comparison is made between the accelerating gradients that can be obtained with this and the preceding types of induction accelerator.

A 10 Billion MeV Cyclotron

ERIC Educational Resources Information Center

Edge, R. D.

1974-01-01

Discusses the design of a device which serves to demonstrate the principle of acceleration and phase stability by accelerating gravitationally a ball bearing along a spiral groove. Application of the design principle to the acceleration aspect of a linear accelerator is recommended. (CC)

Accelerated test design

NASA Technical Reports Server (NTRS)

Mcdermott, P. P.

1980-01-01

The design of an accelerated life test program for electric batteries is discussed. A number of observations and suggestions on the procedures and objectives for conducting an accelerated life test program are presented. Equations based on nonlinear regression analysis for predicting the accelerated life test parameters are discussed.

Design of Linear Accelerator (LINAC) tanks for proton therapy via Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) approaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castellano, T.; De Palma, L.; Laneve, D.

2015-07-01

A homemade computer code for designing a Side- Coupled Linear Accelerator (SCL) is written. It integrates a simplified model of SCL tanks with the Particle Swarm Optimization (PSO) algorithm. The computer code main aim is to obtain useful guidelines for the design of Linear Accelerator (LINAC) resonant cavities. The design procedure, assisted via the aforesaid approach seems very promising, allowing future improvements towards the optimization of actual accelerating geometries. (authors)

Design of an electromagnetic accelerator for turbulent hydrodynamic mix studies

NASA Astrophysics Data System (ADS)

Susoeff, A. R.; Hawke, R. S.; Morrison, J. J.; Dimonte, G.; Remington, B. A.

1993-12-01

An electromagnetic accelerator in the form of a linear electric motor (LEM) has been designed to achieve controlled acceleration profiles of a carriage containing hydrodynamically unstable fluids for the investigation of the development of turbulent mix. The Rayleigh-Taylor instability is investigated by accelerating two dissimilar density fluids using the LEM to achieve a wide variety of acceleration and deceleration profiles. The acceleration profiles are achieved by independent control of rail and augmentation currents. A variety of acceleration-time profiles are possible including: (1) constant, (2) impulsive and (3) shaped. The LEM and support structure are a robust design in order to withstand high loads with deflections and to mitigate operational vibration. Vibration of the carriage during acceleration could create artifacts in the data which would interfere with the intended study of the Rayleigh-Taylor instability. The design allows clear access for diagnostic techniques such as laser induced fluorescence radiography, shadowgraphs and particle imaging velocimetry. Electromagnetic modeling codes were used to optimize the rail and augmentation coil positions within the support structure framework. Results of contemporary studies for non-arcing sliding contact of solid armatures are used for the design of the driving armature and the dynamic electromagnetic braking system. A 0.6MJ electrolytic capacitor bank is used for energy storage to drive the LEM. This report will discuss a LEM design which will accelerate masses of up to 3kg to a maximum of about 3000g(sub o), where g(sub o) is accelerated due to gravity.

Mechanical engineering and design criteria for the Magnetically Insulated Transmission Experiment Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Staller, G.E.; Hamilton, I.D.; Aker, M.F.

1978-02-01

A single-unit electron beam accelerator was designed, fabricated, and assembled in Sandia's Technical Area V to conduct magnetically insulated transmission experiments. Results of these experiments will be utilized in the future design of larger, more complex accelerators. This design makes optimum use of existing facilities and equipment. When designing new components, possible future applications were considered as well as compatibility with existing facilities and hardware.

Accelerating Families of Fuzzy K-Means Algorithms for Vector Quantization Codebook Design

PubMed Central

Mata, Edson; Bandeira, Silvio; de Mattos Neto, Paulo; Lopes, Waslon; Madeiro, Francisco

2016-01-01

The performance of signal processing systems based on vector quantization depends on codebook design. In the image compression scenario, the quality of the reconstructed images depends on the codebooks used. In this paper, alternatives are proposed for accelerating families of fuzzy K-means algorithms for codebook design. The acceleration is obtained by reducing the number of iterations of the algorithms and applying efficient nearest neighbor search techniques. Simulation results concerning image vector quantization have shown that the acceleration obtained so far does not decrease the quality of the reconstructed images. Codebook design time savings up to about 40% are obtained by the accelerated versions with respect to the original versions of the algorithms. PMID:27886061

Accelerating Families of Fuzzy K-Means Algorithms for Vector Quantization Codebook Design.

PubMed

Mata, Edson; Bandeira, Silvio; de Mattos Neto, Paulo; Lopes, Waslon; Madeiro, Francisco

2016-11-23

The performance of signal processing systems based on vector quantization depends on codebook design. In the image compression scenario, the quality of the reconstructed images depends on the codebooks used. In this paper, alternatives are proposed for accelerating families of fuzzy K-means algorithms for codebook design. The acceleration is obtained by reducing the number of iterations of the algorithms and applying efficient nearest neighbor search techniques. Simulation results concerning image vector quantization have shown that the acceleration obtained so far does not decrease the quality of the reconstructed images. Codebook design time savings up to about 40% are obtained by the accelerated versions with respect to the original versions of the algorithms.

Electrostatic design and beam transport for a folded tandem electrostatic quadrupole accelerator facility for accelerator-based boron neutron capture therapy.

PubMed

Vento, V Thatar; Bergueiro, J; Cartelli, D; Valda, A A; Kreiner, A J

2011-12-01

Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT), we discuss here the electrostatic design of the machine, including the accelerator tubes with electrostatic quadrupoles and the simulations for the transport and acceleration of a high intensity beam. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cybermaterials: materials by design and accelerated insertion of materials

NASA Astrophysics Data System (ADS)

Xiong, Wei; Olson, Gregory B.

2016-02-01

Cybermaterials innovation entails an integration of Materials by Design and accelerated insertion of materials (AIM), which transfers studio ideation into industrial manufacturing. By assembling a hierarchical architecture of integrated computational materials design (ICMD) based on materials genomic fundamental databases, the ICMD mechanistic design models accelerate innovation. We here review progress in the development of linkage models of the process-structure-property-performance paradigm, as well as related design accelerating tools. Extending the materials development capability based on phase-level structural control requires more fundamental investment at the level of the Materials Genome, with focus on improving applicable parametric design models and constructing high-quality databases. Future opportunities in materials genomic research serving both Materials by Design and AIM are addressed.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spentzouris, P.; /Fermilab; Cary, J.

The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessarymore » accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization for software development and applications accounts for the natural domain areas (beam dynamics, electromagnetics, and advanced acceleration), and all areas depend on the enabling technologies activities, such as solvers and component technology, to deliver the desired performance and integrated simulation environment. The ComPASS applications focus on computationally challenging problems important for design or performance optimization to all major HEP, NP, and BES accelerator facilities. With the cost and complexity of particle accelerators rising, the use of computation to optimize their designs and find improved operating regimes becomes essential, potentially leading to significant cost savings with modest investment.« less

Dynamics of High Temperature Plasmas.

DTIC Science & Technology

1985-10-01

25 VI. > LASER BEAT WAVE PARTICLE ACCELERATION-.. ..... .. 27 ,, VII. ORBITRON MASER DESIGN .. ..... ............. 30 0 VIIM> ELECTRON BEAM STABILITY...IN THE MODIFIED BETATRON .... ............ 32 IX. * RELATIVISTIC ELECTRON BEAM DIODE DESIGN . . . . 35 X. FREE ELECTRON LASER APPLICATION TO XUV...Accelerators (B), VI. Laser Beat Wave Particle Acceleration, VII. Orbitron Maser Design , VIII. Electron Beam Stability in the Modified Betatron, IX

Recirculating linacs for a neutrino factory - Arc optics design and optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alex Bogacz; Valeri Lebedev

2001-10-21

A conceptual lattice design for a muon accelerator based on recirculating linacs (Nucl. Instr. and Meth. A 472 (2001) 499, these proceedings) is presented here. The challenge of accelerating and transporting a large phase space of short-lived muons is answered here by presenting a proof-of-principle lattice design for a recirculating linac accelerator. It is the centerpiece of a chain of accelerators consisting of a 3GeV linac and two consecutive recirculating linear accelerators, which facilitates acceleration starting after ionization cooling at 190MeV/c and proceeding to 50GeV. Beam transport issues for large-momentum-spread beams are accommodated by appropriate lattice design choices. The resultingmore » arc optics is further optimized with a sextupole correction to suppress chromatic effects contributing to the emittance dilution. The presented proof-of-principle design of the arc optics with horizontal separation of multi-pass beams can be extended to all passes in both recirculating linacs.« less

Model-based Acceleration Control of Turbofan Engines with a Hammerstein-Wiener Representation

NASA Astrophysics Data System (ADS)

Wang, Jiqiang; Ye, Zhifeng; Hu, Zhongzhi; Wu, Xin; Dimirovsky, Georgi; Yue, Hong

2017-05-01

Acceleration control of turbofan engines is conventionally designed through either schedule-based or acceleration-based approach. With the widespread acceptance of model-based design in aviation industry, it becomes necessary to investigate the issues associated with model-based design for acceleration control. In this paper, the challenges for implementing model-based acceleration control are explained; a novel Hammerstein-Wiener representation of engine models is introduced; based on the Hammerstein-Wiener model, a nonlinear generalized minimum variance type of optimal control law is derived; the feature of the proposed approach is that it does not require the inversion operation that usually upsets those nonlinear control techniques. The effectiveness of the proposed control design method is validated through a detailed numerical study.

Advanced Beamline Design for Fermilab's Advanced Superconducting Test Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prokop, Christopher

2014-01-01

The Advanced Superconducting Test Accelerator (ASTA) at Fermilab is a new electron accelerator currently in the commissioning stage. In addition to testing superconducting accelerating cavities for future accelerators, it is foreseen to support a variety of Advanced Accelerator R&D (AARD) experiments. Producing the required electron bunches with the expected flexibility is challenging. The goal of this dissertation is to explore via numerical simulations new accelerator beamlines that can enable the advanced manipulation of electron bunches. The work especially includes the design of a low-energy bunch compressor and a study of transverse-to-longitudinal phase space exchangers.

Equivalent-Groups versus Single-Group Equating Designs for the Accelerated CAT-ASVAB (Computerized Adaptive Test-Armed Services Vocational Aptitude Battery) Project.

DTIC Science & Technology

1987-01-01

DESIGNS FOR THE ACCELERATED CAT -ASVAB * PROJECT Peter H. Stoloff DTIC’- , " SELECTE -NOV 2 3 987 A Division of Hudson Institute CENTER FOR NAVAL ANALYSES...65153M C0031 SI TITLE (Include Security Classification) Equivalent-Groups Versus Single-Group Equating Designs For The Accelerated CAT -ASVAB Project...GROUP ACAP (Accelerated CAT -ASVAB Program), Aptitude tests, ASVAB (Armed 05 10 Services Vocational Aptitude Battery), CAT (Computerized Adaptive Test

Accelerating Cogent Confabulation: An Exploration in the Architecture Design Space

DTIC Science & Technology

2008-06-01

DATES COVERED (From - To) 1-8 June 2008 4. TITLE AND SUBTITLE ACCELERATING COGENT CONFABULATION: AN EXPLORATION IN THE ARCHITECTURE DESIGN SPACE 5a...spiking neural networks is proposed in reference [8]. Reference [9] investigates the architecture design of a Brain-state-in-a-box model. The...Richard Linderman2, Thomas Renz2, Qing Wu1 Accelerating Cogent Confabulation: an Exploration in the Architecture Design Space POSTPRINT complexity

Design considerations and test facilities for accelerated radiation effects testing

NASA Technical Reports Server (NTRS)

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

1972-01-01

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

[Shielding design and detection of neutrons from medical and industrial electron accelerators--simple method of design calculation for neutron shielding].

PubMed

Nakamura, T; Uwamino, Y

1986-02-01

The neutron leakage from medical and industrial electron accelerators has become an important problem and its detection and shielding is being performed in their facilities. This study provides a new simple method of design calculation for neutron shielding of those electron accelerator facilities by dividing into the following five categories; neutron dose distribution in the accelerator room, neutron attenuation through the wall and the door in the accelerator room, neutron and secondary photon dose distributions in the maze, neutron and secondary photon attenuation through the door at the end of the maze, neutron leakage outside the facility-skyshine.

Foreground Subtraction and Signal reconstruction in redshifted 21cm Global Signal Experiments using Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Choudhury, Madhurima; Datta, Abhirup

2018-05-01

Observations of HI 21cm transition line is a promising probe into the Dark Ages and Epoch-of-Reionization. Detection of this redshifted 21cm signal is one of the key science goal for several upcoming low-frequency radio telescopes like HERA, SKA and DARE. Other global signal experiments include EDGES, LEDA, BIGHORNS, SCI-HI, SARAS. One of the major challenges for the detection of this signal is the accuracy of the foreground source removal. Several novel techniques have been explored already to remove bright foregrounds from both interferometric as well as total power experiments. Here, we present preliminary results from our investigation on application of ANN to detect 21cm global signal amidst bright galactic foreground. Following the formalism of representing the global 21cm signal by 'tanh' model, this study finds that the global 21cm signal parameters can be accurately determined even in the presence of bright foregrounds represented by 3rd order log-polynomial or higher.

A theory of germinal center B cell selection, division, and exit.

PubMed

Meyer-Hermann, Michael; Mohr, Elodie; Pelletier, Nadége; Zhang, Yang; Victora, Gabriel D; Toellner, Kai-Michael

2012-07-26

High-affinity antibodies are generated in germinal centers in a process involving mutation and selection of B cells. Information processing in germinal center reactions has been investigated in a number of recent experiments. These have revealed cell migration patterns, asymmetric cell divisions, and cell-cell interaction characteristics, used here to develop a theory of germinal center B cell selection, division, and exit (the LEDA model). According to this model, B cells selected by T follicular helper cells on the basis of successful antigen processing always return to the dark zone for asymmetric division, and acquired antigen is inherited by one daughter cell only. Antigen-retaining B cells differentiate to plasma cells and leave the germinal center through the dark zone. This theory has implications for the functioning of germinal centers because compared to previous models, high-affinity antibodies appear one day earlier and the amount of derived plasma cells is considerably larger. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

Seismic site coefficients and acceleration design response spectra based on conditions in South Carolina : final report.

DOT National Transportation Integrated Search

2014-11-15

The simplified procedure in design codes for determining earthquake response spectra involves : estimating site coefficients to adjust available rock accelerations to site accelerations. Several : investigators have noted concerns with the site coeff...

Design study of electron cyclotron resonance-ion plasma accelerator for heavy ion cancer therapy.

PubMed

Inoue, T; Hattori, T; Sugimoto, S; Sasai, K

2014-02-01

Electron Cyclotron Resonance-Ion Plasma Accelerator (ECR-IPAC) device, which theoretically can accelerate multiple charged ions to several hundred MeV with short acceleration length, has been proposed. The acceleration mechanism is based on the combination of two physical principles, plasma electron ion adiabatic ejection (PLEIADE) and Gyromagnetic Autoresonance (GYRAC). In this study, we have designed the proof of principle machine ECR-IPAC device and simulated the electromagnetic field distribution generating in the resonance cavity. ECR-IPAC device consisted of three parts, ECR ion source section, GYRAC section, and PLEIADE section. ECR ion source section and PLEIADE section were designed using several multi-turn solenoid coils and sextupole magnets, and GYRAC section was designed using 10 turns coil. The structure of ECR-IPAC device was the cylindrical shape, and the total length was 1024 mm and the maximum diameter was 580 mm. The magnetic field distribution, which maintains the stable acceleration of plasma, was generated on the acceleration center axis throughout three sections. In addition, the electric field for efficient acceleration of electrons was generated in the resonance cavity by supplying microwave of 2.45 GHz.

RFQ design for the RAON accelerator's ISOL system

NASA Astrophysics Data System (ADS)

Choi, Bong Hyuk; Hong, In-Seok

2015-10-01

The heavy-ion accelerator RAON has the advantage of having both an in-flight (IF) and an isotope separator on-line (ISOL) system. Two radio frequency quadrupoles (RFQs) will be installed in the RAON: the main linear accelerator (LINAC) RFQ will be used to accelerate the two-charge state 238U for the IF system, while the post-accelerator RFQ will be used to accelerate low-current isotope beams from the ISOL system. In this paper, the post-accelerator RFQ design for the ISOL system is reported. A beam current of 1 pμA was used, and the input beam and the output beam energies were 5 keV/u and 400 keV/u, respectively. Moreover, the design was optimized by reducing the total length and power, adjusting the beam quality. To quantify the influence of thermal expansion on the frequency, we calculated the frequency difference according to deference between the vane's tip and the body's diameter.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soong, Ken; Peralta, E.A.; Byer, R.L.

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,more » 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 realizable structure. In this paper, we will present a 3-dimensional frequency-domain simulation of both the infinite and the finite grating accelerator structure. Additionally, we will present a new scheme for a focusing structure based on a perturbation of the accelerating structure. We will present simulations of this proposed focusing structure and quantify the quality of the focusing fields.« less

The LeRC rail accelerators: Test designs and diagnostic techniques

NASA Technical Reports Server (NTRS)

Zana, L. M.; Kerslake, W. R.; Sturman, J. C.; Wang, S. Y.; Terdan, F. F.

1983-01-01

The feasibility of using rail accelerators for various in-space and to-space propulsion applications was investigated. A 1 meter, 24 sq mm bore accelerator was designed with the goal of demonstrating projectile velocities of 15 km/sec using a peak current of 200 kA. A second rail accelerator, 1 meter long with a 156.25 sq mm bore, was designed with clear polycarbonate sidewalls to permit visual observation of the plasma arc. A study of available diagnostic techniques and their application to the rail accelerator is presented. Specific topics of discussion include the use of interferometry and spectroscopy to examine the plasma armature as well as the use of optical sensors to measure rail displacement during acceleration. Standard diagnostics such as current and voltage measurements are also discussed.

Recirculating linacs for a neutrino factory - Arc optics design and optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valeri Lebedev; S. Bogacz

2001-10-25

A conceptual lattice design for a muon accelerator based on recirculating linacs (Nucl. Instr. and Meth. A 472 (2001) 499, these proceedings) is presented here. The challenge of accelerating and transporting a large phase space of short-lived muons is answered here by presenting a proof-of-principle lattice design for a recirculating linac accelerator. It is the centerpiece of a chain of accelerators consisting of a 3 GeV linac and two consecutive recirculating linear accelerators, which facilitates acceleration starting after ionization cooling at 190 MeV/c and proceeding to 50 GeV. Beam transport issues for large-momentum-spread beams are accommodated by appropriate lattice designmore » choices. The resulting arc optics is further optimized with a sextupole correction to suppress chromatic effects contributing to the emittance dilution. The presented proof-of-principle design of the arc optics with horizontal separation of multi-pass beams can be extended to all passes in both recirculating linacs.« less

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.

Self-shielded electron linear accelerators designed for radiation technologies

NASA Astrophysics Data System (ADS)

Belugin, V. M.; Rozanov, N. E.; Pirozhenko, V. M.

2009-09-01

This paper describes self-shielded high-intensity electron linear accelerators designed for radiation technologies. The specific property of the accelerators is that they do not apply an external magnetic field; acceleration and focusing of electron beams are performed by radio-frequency fields in the accelerating structures. The main characteristics of the accelerators are high current and beam power, but also reliable operation and a long service life. To obtain these characteristics, a number of problems have been solved, including a particular optimization of the accelerator components and the application of a variety of specific means. The paper describes features of the electron beam dynamics, accelerating structure, and radio-frequency power supply. Several compact self-shielded accelerators for radiation sterilization and x-ray cargo inspection have been created. The introduced methods made it possible to obtain a high intensity of the electron beam and good performance of the accelerators.

Overview of the design of the ITER heating neutral beam injectors

NASA Astrophysics Data System (ADS)

Hemsworth, R. S.; Boilson, D.; Blatchford, P.; Dalla Palma, M.; Chitarin, G.; de Esch, H. P. L.; Geli, F.; Dremel, M.; Graceffa, J.; Marcuzzi, D.; Serianni, G.; Shah, D.; Singh, M.; Urbani, M.; Zaccaria, P.

2017-02-01

The heating neutral beam injectors (HNBs) of ITER are designed to deliver 16.7 MW of 1 MeV D0 or 0.87 MeV H0 to the ITER plasma for up to 3600 s. They will be the most powerful neutral beam (NB) injectors ever, delivering higher energy NBs to the plasma in a tokamak for longer than any previous systems have done. The design of the HNBs is based on the acceleration and neutralisation of negative ions as the efficiency of conversion of accelerated positive ions is so low at the required energy that a realistic design is not possible, whereas the neutralisation of H- and D- remains acceptable (≈56%). The design of a long pulse negative ion based injector is inherently more complicated than that of short pulse positive ion based injectors because: • negative ions are harder to create so that they can be extracted and accelerated from the ion source; • electrons can be co-extracted from the ion source along with the negative ions, and their acceleration must be minimised to maintain an acceptable overall accelerator efficiency; • negative ions are easily lost by collisions with the background gas in the accelerator; • electrons created in the extractor and accelerator can impinge on the extraction and acceleration grids, leading to high power loads on the grids; • positive ions are created in the accelerator by ionisation of the background gas by the accelerated negative ions and the positive ions are back-accelerated into the ion source creating a massive power load to the ion source; • electrons that are co-accelerated with the negative ions can exit the accelerator and deposit power on various downstream beamline components. The design of the ITER HNBs is further complicated because ITER is a nuclear installation which will generate very large fluxes of neutrons and gamma rays. Consequently all the injector components have to survive in that harsh environment. Additionally the beamline components and the NB cell, where the beams are housed, will be activated and all maintenance will have to be performed remotely. This paper describes the design of the HNB injectors, but not the associated power supplies, cooling system, cryogenic system etc, or the high voltage bushing which separates the vacuum of the beamline from the high pressure SF6 of the high voltage (1 MV) transmission line, through which the power, gas and cooling water are supplied to the beam source. Also the magnetic field reduction system is not described.

Accelerated Reader. What Works Clearinghouse Intervention Report

ERIC Educational Resources Information Center

What Works Clearinghouse, 2009

2009-01-01

"Accelerated Reader" is a computer-based reading management system designed to complement an existing classroom literacy program for grades pre-K-12. It is designed to increase the amount of time students spend reading independently. Students choose reading-level appropriate books or short stories for which Accelerated Reader tests are…

7 CFR 3201.64 - Compost activators and accelerators.

Code of Federal Regulations, 2014 CFR

2014-01-01

... PROCUREMENT Designated Items § 3201.64 Compost activators and accelerators. (a) Definition. Products in liquid or powder form designed to be applied to compost piles to aid in speeding up the composting process... 7 Agriculture 15 2014-01-01 2014-01-01 false Compost activators and accelerators. 3201.64 Section...

7 CFR 3201.64 - Compost activators and accelerators.

Code of Federal Regulations, 2013 CFR

2013-01-01

... PROCUREMENT Designated Items § 3201.64 Compost activators and accelerators. (a) Definition. Products in liquid or powder form designed to be applied to compost piles to aid in speeding up the composting process... 7 Agriculture 15 2013-01-01 2013-01-01 false Compost activators and accelerators. 3201.64 Section...

7 CFR 3201.64 - Compost activators and accelerators.

Code of Federal Regulations, 2012 CFR

2012-01-01

... PROCUREMENT Designated Items § 3201.64 Compost activators and accelerators. (a) Definition. Products in liquid or powder form designed to be applied to compost piles to aid in speeding up the composting process... 7 Agriculture 15 2012-01-01 2012-01-01 false Compost activators and accelerators. 3201.64 Section...

A feasibility study of a hypersonic real-gas facility

NASA Technical Reports Server (NTRS)

Gully, J. H.; Driga, M. D.; Weldon, W. F.

1987-01-01

A four month feasibility study of a hypersonic real-gas free flight test facility for NASA Langley Research Center (LARC) was performed. The feasibility of using a high-energy electromagnetic launcher (EML) to accelerate complex models (lifting and nonlifting) in the hypersonic, real-gas facility was examined. Issues addressed include: design and performance of the accelerator; design and performance of the power supply; design and operation of the sabot and payload during acceleration and separation; effects of high current, magnetic fields, temperature, and stress on the sabot and payload; and survivability of payload instrumentation during acceleration, flight, and soft catch.

Design of an 81.25 MHz continuous-wave radio-frequency quadrupole accelerator for Low Energy Accelerator Facility

NASA Astrophysics Data System (ADS)

Ma, Wei; Lu, Liang; Xu, Xianbo; Sun, Liepeng; Zhang, Zhouli; Dou, Weiping; Li, Chenxing; Shi, Longbo; He, Yuan; Zhao, Hongwei

2017-03-01

An 81.25 MHz continuous wave (CW) radio frequency quadrupole (RFQ) accelerator has been designed for the Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). In the CW operating mode, the proposed RFQ design adopted the conventional four-vane structure. The main design goals are providing high shunt impendence with low power losses. In the electromagnetic (EM) design, the π-mode stabilizing loops (PISLs) were optimized to produce a good mode separation. The tuners were also designed and optimized to tune the frequency and field flatness of the operating mode. The vane undercuts were optimized to provide a flat field along the RFQ cavity. Additionally, a full length model with modulations was set up for the final EM simulations. Following the EM design, thermal analysis of the structure was carried out. In this paper, detailed EM design and thermal simulations of the LEAF-RFQ will be presented and discussed. Structure error analysis was also studied.

Studies on Muon Induction Acceleration and an Objective Lens Design for Transmission Muon Microscope

NASA Astrophysics Data System (ADS)

Artikova, Sayyora; Yoshida, Mitsuhiro; Naito, Fujio

Muon acceleration will be accomplished by a set of induction cells, where each increases the energy of the muon beam by an increment of up to 30 kV. The cells are arranged in a linear way resulting in total accelerating voltage of 300 kV. Acceleration time in the linac is about hundred nanoseconds. Induction field calculation is based on an electrostatic approximation. Beam dynamics in the induction accelerator is investigated and final beam focusing on specimen is realized by designing a pole piece lens.

Acceleration sensitivity of micromachined pressure sensors

NASA Astrophysics Data System (ADS)

August, Richard; Maudie, Theresa; Miller, Todd F.; Thompson, Erik

1999-08-01

Pressure sensors serve a variety of automotive applications, some which may experience high levels of acceleration such as tire pressure monitoring. To design pressure sensors for high acceleration environments it is important to understand their sensitivity to acceleration especially if thick encapsulation layers are used to isolate the device from the hostile environment in which they reside. This paper describes a modeling approach to determine their sensitivity to acceleration that is very general and is applicable to different device designs and configurations. It also describes the results of device testing of a capacitive surface micromachined pressure sensor at constant acceleration levels from 500 to 2000 g's.

KLYNAC: Compact linear accelerator with integrated power supply

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malyzhenkov, Alexander

Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scienti c community is working towards improving the quality of the accelerated beam and its parameters while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype, resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RFmore » source, an accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simpli ed theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using particle-in-cell simulation studies for mono- resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.« less

Klynac: Compact Linear Accelerator with Integrated Power Supply

NASA Astrophysics Data System (ADS)

Malyzhenkov, A. V.

Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scientific community is working towards improving the quality of the accelerated beam and its parameters, while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype: resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RF source, accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simplified theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using Particle-In-Cell simulation studies for mono-resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.

Beam Position Monitoring in the CSU Accelerator Facility

NASA Astrophysics Data System (ADS)

Einstein, Joshua; Vankeuren, Max; Watras, Stephen

2014-03-01

A Beam Position Monitoring (BPM) system is an integral part of an accelerator beamline, and modern accelerators can take advantage of newer technologies and designs when creating a BPM system. The Colorado State University (CSU) Accelerator Facility will include four stripline detectors mounted around the beamline, a low-noise analog front-end, and digitization and interface circuitry. The design will support a sampling rate greater than 10 Hz and sub-100 μm accuracy.

Design of four-beam IH-RFQ linear accelerator

NASA Astrophysics Data System (ADS)

Ikeda, Shota; Murata, Aki; Hayashizaki, Noriyosu

2017-09-01

The multi-beam acceleration method is an acceleration technique for low-energy high-intensity heavy ion beams, which involves accelerating multiple beams to decrease space charge effects, and then integrating these beams by a beam funneling system. At the Tokyo Institute of Technology a two beam IH-RFQ linear accelerator was developed using a two beam laser ion source with direct plasma injection scheme. This system accelerated a carbon ion beam with a current of 108 mA (54 mA/channel × 2) from 5 up to 60 keV/u. In order to demonstrate that a four-beam IH-RFQ linear accelerator is suitable for high-intensity heavy ion beam acceleration, we have been developing a four-beam prototype. A four-beam IH-RFQ linear accelerator consists of sixteen RFQ electrodes (4 × 4 set) with stem electrodes installed alternately on the upper and lower ridge electrodes. As a part of this development, we have designed a four-beam IH-RFQ linear accelerator using three dimensional electromagnetic simulation software and beam tracking simulation software. From these simulation results, we have designed the stem electrodes, the center plate and the side shells by evaluating the RF properties such as the resonance frequency, the power loss and the electric strength distribution between the RFQ electrodes.

Accelerator Technology Division annual report, FY 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-06-01

This paper discusses: accelerator physics and special projects; experiments and injectors; magnetic optics and beam diagnostics; accelerator design and engineering; radio-frequency technology; accelerator theory and simulation; free-electron laser technology; accelerator controls and automation; and high power microwave sources and effects.

An Integrated Circuit for Radio Astronomy Correlators Supporting Large Arrays of Antennas

NASA Technical Reports Server (NTRS)

D'Addario, Larry R.; Wang, Douglas

2016-01-01

Radio telescopes that employ arrays of many antennas are in operation, and ever larger ones are being designed and proposed. Signals from the antennas are combined by cross-correlation. While the cost of most components of the telescope is proportional to the number of antennas N, the cost and power consumption of cross-correlationare proportional to N2 and dominate at sufficiently large N. Here we report the design of an integrated circuit (IC) that performs digital cross-correlations for arbitrarily many antennas in a power-efficient way. It uses an intrinsically low-power architecture in which the movement of data between devices is minimized. In a large system, each IC performs correlations for all pairs of antennas but for a portion of the telescope's bandwidth (the so-called "FX" structure). In our design, the correlations are performed in an array of 4096 complex multiply-accumulate (CMAC) units. This is sufficient to perform all correlations in parallel for 64 signals (N=32 antennas with 2 opposite-polarization signals per antenna). When N is larger, the input data are buffered in an on-chipmemory and the CMACs are re-used as many times as needed to compute all correlations. The design has been synthesized and simulated so as to obtain accurate estimates of the IC's size and power consumption. It isintended for fabrication in a 32 nm silicon-on-insulator process, where it will require less than 12mm2 of silicon area and achieve an energy efficiency of 1.76 to 3.3 pJ per CMAC operation, depending on the number of antennas. Operation has been analyzed in detail up to N = 4096. The system-level energy efficiency, including board-levelI/O, power supplies, and controls, is expected to be 5 to 7 pJ per CMAC operation. Existing correlators for the JVLA (N = 32) and ALMA (N = 64) telescopes achieve about 5000 pJ and 1000 pJ respectively usingapplication-specific ICs in older technologies. To our knowledge, the largest-N existing correlator is LEDA atN = 256; it uses GPUs built in 28 nm technology and achieves about 1000 pJ. Correlators being designed for the SKA telescopes (N = 128 and N = 512) using FPGAs in 16nm technology are predicted to achieve about 100 pJ.

Accelerated longitudinal designs: An overview of modelling, power, costs and handling missing data.

PubMed

Galbraith, Sally; Bowden, Jack; Mander, Adrian

2017-02-01

Longitudinal studies are often used to investigate age-related developmental change. Whereas a single cohort design takes a group of individuals at the same initial age and follows them over time, an accelerated longitudinal design takes multiple single cohorts, each one starting at a different age. The main advantage of an accelerated longitudinal design is its ability to span the age range of interest in a shorter period of time than would be possible with a single cohort longitudinal design. This paper considers design issues for accelerated longitudinal studies. A linear mixed effect model is considered to describe the responses over age with random effects for intercept and slope parameters. Random and fixed cohort effects are used to cope with the potential bias accelerated longitudinal designs have due to multiple cohorts. The impact of other factors such as costs and the impact of dropouts on the power of testing or the precision of estimating parameters are examined. As duration-related costs increase relative to recruitment costs the best designs shift towards shorter duration and eventually cross-sectional design being best. For designs with the same duration but differing interval between measurements, we found there was a cutoff point for measurement costs relative to recruitment costs relating to frequency of measurements. Under our model of 30% dropout there was a maximum power loss of 7%.

The mechatronic design of a fast wire scanner in IHEP U-70 accelerator

NASA Astrophysics Data System (ADS)

Baranov, V. T.; Makhov, S. S.; Savin, D. A.; Terekhov, V. I.

2016-10-01

This paper presents the mechatronic design of a fast wire scanner based on a servomotor. The design of the wire scanner is motivated by the need to measure the transverse profile of the high power proton and carbon beams at the IHEP U-70 accelerator. This paper formulates the requirements to the fast wire scanner system for the high intensity proton beam at the U-70 accelerator. The results on the design of electro-mechanical device for the wire scanner with a wire traveling speed 10-20 m/s are presented. The solution consists in a brushless servomotor and standard motor control electronics. High radiation levels in the accelerator enclosure dictate the use of a resolver as the position feedback element.

Accelerated Districts--The Next Step. A Summary of Research and Design.

ERIC Educational Resources Information Center

Driver, Cyrus; And Others

The National Center for the Accelerated Schools Project at Stanford University has recognized that district-level change is necessary if changes at accelerated schools are to gain permanence and become widespread. The Center has therefore initiated a research and development project to design a set of models on which districts can reconstitute…

MABE multibeam accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasti, D.E.; Ramirez, J.J.; Coleman, P.D.

1985-01-01

The Megamp Accelerator and Beam Experiment (MABE) was the technology development testbed for the multiple beam, linear induction accelerator approach for Hermes III, a new 20 MeV, 0.8 MA, 40 ns accelerator being developed at Sandia for gamma-ray simulation. Experimental studies of a high-current, single-beam accelerator (8 MeV, 80 kA), and a nine-beam injector (1.4 MeV, 25 kA/beam) have been completed, and experiments on a nine-beam linear induction accelerator are in progress. A two-beam linear induction accelerator is designed and will be built as a gamma-ray simulator to be used in parallel with Hermes III. The MABE pulsed power systemmore » and accelerator for the multiple beam experiments is described. Results from these experiments and the two-beam design are discussed. 11 refs., 6 figs.« less

Seismic design parameters - A user guide

USGS Publications Warehouse

Leyendecker, E.V.; Frankel, A.D.; Rukstales, K.S.

2001-01-01

The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings (1997 NEHRP Provisions) introduced seismic design procedure that is based on the explicit use of spectral response acceleration rather than the traditional peak ground acceleration and/or peak ground velocity or zone factors. The spectral response accelerations are obtained from spectral response acceleration maps accompanying the report. Maps are available for the United States and a number of U.S. territories. Since 1997 additional codes and standards have also adopted seismic design approaches based on the same procedure used in the NEHRP Provisions and the accompanying maps. The design documents using the 1997 NEHRP Provisions procedure may be divided into three categories -(1) Design of New Construction, (2) Design and Evaluation of Existing Construction, and (3) Design of Residential Construction. A CD-ROM has been prepared for use in conjunction with the design documents in each of these three categories. The spectral accelerations obtained using the software on the CD are the same as those that would be obtained by using the maps accompanying the design documents. The software has been prepared to operate on a personal computer using a Windows (Microsoft Corporation) operating environment and a point and click type of interface. The user can obtain the spectral acceleration values that would be obtained by use of the maps accompanying the design documents, include site factors appropriate for the Site Class provided by the user, calculate a response spectrum that includes the site factor, and plot a response spectrum. Sites may be located by providing the latitude-longitude or zip code for all areas covered by the maps. All of the maps used in the various documents are also included on the CDROM

Ultra-High Gradient S-band Linac for Laboratory and Industrial Applications

NASA Astrophysics Data System (ADS)

Faillace, L.; Agustsson, R.; Dolgashev, V.; Frigola, P.; Murokh, A.; Rosenzweig, J.; Yakimenko, V.

2010-11-01

A strong demand for high gradient structures arises from the limited real estate available for linear accelerators. RadiaBeam Technologies is developing a Doubled Energy Compact Accelerator (DECA) structure: an S-band standing wave electron linac designed to operate at accelerating gradients of up to 50 MV/m. In this paper, we present the radio-frequency design of the DECA S-band accelerating structure, operating at 2.856 GHz in the π-mode. The structure design is heavily influenced by NLC collaboration experience with ultra high gradient X-band structures; S-band, however, is chosen to take advantage of commonly available high power S-band klystrons.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spentzouris, Panagiotis; /Fermilab; Cary, John

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

Analytical study of beam handling and emittance control

NASA Astrophysics Data System (ADS)

Thompson, James R.; Sloan, M. L.

1993-12-01

The thrust of our research on beam handling and emittance control was to explore how one might design high current electron accelerators, with the preservation of high beam quality designed as the primary design consideration. We considered high current, induction linacs in the parameter class of the ETA/ATA accelerators at LLNL, but with improvements to the accelerator gap design and other features to permit a significant increase in the deliverable beam brightness. Our approach for beam quality control centered on the use of solenoidal magnetic focusing through such induction accelerators, together with gently-shaped (adiabatic) acceleration gaps. This approach offers several tools for the control of beam quality. The strength and axial variation in the solenoidal magnetic field may be designed, as may the length and shape of the acceleration gaps, the loading of the gaps, and the axial spacing from gap to gap. This research showed that each of these design features may individually be optimized to contribute to improved beam quality control, and by exploiting these features, it appears feasible to produce high current, high energy electron beams possessing breakthrough beam quality and brightness. Applications which have been technologically unachievable may for the first time become possible. One such application is the production of high performance free electron lasers at very short wavelengths, extending down to the optical (less than 1 micron) regime.

Mechanical design optimization of a single-axis MOEMS accelerometer based on a grating interferometry cavity for ultrahigh sensitivity

NASA Astrophysics Data System (ADS)

Lu, Qianbo; Bai, Jian; Wang, Kaiwei; Lou, Shuqi; Jiao, Xufen; Han, Dandan; Yang, Guoguang

2016-08-01

The ultrahigh static displacement-acceleration sensitivity of a mechanical sensing chip is essential primarily for an ultrasensitive accelerometer. In this paper, an optimal design to implement to a single-axis MOEMS accelerometer consisting of a grating interferometry cavity and a micromachined sensing chip is presented. The micromachined sensing chip is composed of a proof mass along with its mechanical cantilever suspension and substrate. The dimensional parameters of the sensing chip, including the length, width, thickness and position of the cantilevers are evaluated and optimized both analytically and by finite-element-method (FEM) simulation to yield an unprecedented acceleration-displacement sensitivity. Compared with one of the most sensitive single-axis MOEMS accelerometers reported in the literature, the optimal mechanical design can yield a profound sensitivity improvement with an equal footprint area, specifically, 200% improvement in displacement-acceleration sensitivity with moderate resonant frequency and dynamic range. The modified design was microfabricated, packaged with the grating interferometry cavity and tested. The experimental results demonstrate that the MOEMS accelerometer with modified design can achieve the acceleration-displacement sensitivity of about 150μm/g and acceleration sensitivity of greater than 1500V/g, which validates the effectiveness of the optimal design.

AT2 DS II - Accelerator System Design (Part II) - CCC Video Conference

ScienceCinema

None

2017-12-09

Discussion Session - Accelerator System Design (Part II) Tutors: C. Darve, J. Weisend II, Ph. Lebrun, A. Dabrowski, U. Raich Video Conference with the CERN Control Center. Experts in the field of Accelerator science will be available to answer the students questions. This session will link the CCC and SA (using Codec VC).

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…

Three dimensional finite element methods: Their role in the design of DC accelerator systems

NASA Astrophysics Data System (ADS)

Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W.

2013-04-01

High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 × 300 mm2. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.

Design of a side coupled standing wave accelerating tube for NSTRI e-Linac

NASA Astrophysics Data System (ADS)

Zarei, S.; Abbasi Davani, F.; Lamehi Rachti, M.; Ghasemi, F.

2017-09-01

The design and construction of a 6 MeV electron linear accelerator (e-Linac) was defined in the Institute of Nuclear Science and Technology (NSTRI) for cargo inspection and medical applications. For this accelerator, a side coupled standing wave tube resonant at a frequency of 2998.5 MHZ in π/2 mode was selected. In this article, the authors provide a step-by-step explanation of the process of the design for this tube. The design and simulation of the accelerating and coupling cavities were carried out in five steps; (1) separate design of the accelerating and coupling cavities, (2) design of the coupling aperture between the cavities, (3) design of the entire structure for resonance at the nominal frequency, (4) design of the buncher, and (5) design of the power coupling port. At all design stages, in addition to finding the dimensions of the cavity, the impact of construction tolerances and simulation errors on the electromagnetic parameters were investigated. The values obtained for the coupling coefficient, coupling constant, quality factor and capture efficiency are 2.11, 0.011, 16203 and 36%, respectively. The results of beam dynamics study of the simulated tube in ASTRA have yielded a value of 5.14 π-mm-mrad for the horizontal emittance, 5.06 π-mm-mrad for the vertical emittance, 1.17 mm for the horizontal beam size, 1.16 mm for the vertical beam size and 1090 keV for the energy spread of the output beam.

Design of a Low-Energy FARAD Thruster

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Rose, M. F.; Miller, R.; Best, S.; Owens, T.; Dankanich, J.

2007-01-01

The design of an electrodeless thruster that relies on a pulsed, rf-assisted discharge and electromagnetic acceleration using an inductive coil is presented. The thruster design is optimized using known performance,scaling parameters, and experimentally-determined design rules, with design targets for discharge energy, plasma exhaust velocity; and thrust efficiency of 100 J/pulse, 25 km/s, and 50%, respectively. Propellant is injected using a high-speed gas valve and preionized by a pulsed-RF signal supplied by a vector inversion generator, allowing for current sheet formation at lower discharge voltages and energies relative to pulsed inductive accelerators that do not employ preionization. The acceleration coil is designed to possess an inductance of at least 700 nH while the target stray (non-coil) inductance in the circuit is 70 nH. A Bernardes and Merryman pulsed power train or a pulse compression power train provide current to the acceleration coil and solid-state components are used to switch both powertrains.

Five-cell superconducting RF module with a PBG coupler cell: design and cold testing of the copper prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arsenyev, Sergey Andreyevich; Simakov, Evgenya Ivanovna; Shchegolkov, Dmitry

2015-04-29

We report the design and experimental data for a copper prototype of a superconducting radio-frequency (SRF) accelerator module. The five-cell module has an incorporated photonic band gap (PBG) cell with couplers. The purpose of the PBG cell is to achieve better higher order mode (HOM) damping, which is vital for preserving the quality of high-current electron beams. Better HOM damping raises the current threshold for beam instabilities in novel SRF accelerators. The PBG design also increases the real-estate gradient of the linac because both HOM damping and the fundamental power coupling can be done through the PBG cell instead ofmore » on the beam pipe via complicated end assemblies. First, we will discuss the design and accelerating properties of the structure. The five-cell module was optimized to provide good HOM damping while maintaining the same accelerating properties as conventional elliptical-cell modules. We will then discuss the process of tuning the structure to obtain the desired accelerating gradient profile. Finally, we will list measured quality factors for the accelerating mode and the most dangerous HOMs.« less

Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion.

PubMed

Kojima, A; Hanada, M; Tobari, H; Nishikiori, R; Hiratsuka, J; Kashiwagi, M; Umeda, N; Yoshida, M; Ichikawa, M; Watanabe, K; Yamano, Y; Grisham, L R

2016-02-01

Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kojima, A., E-mail: kojima.atsushi@jaea.go.jp; Hanada, M.; Tobari, H.

Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltagemore » holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lovelace, III, Henry H.

In accelerator physics, models of a given machine are used to predict the behaviors of the beam, magnets, and radiofrequency cavities. The use of the computational model has become wide spread to ease the development period of the accelerator lattice. There are various programs that are used to create lattices and run simulations of both transverse and longitudinal beam dynamics. The programs include Methodical Accelerator Design(MAD) MAD8, MADX, Zgoubi, Polymorphic Tracking Code (PTC), and many others. In this discussion the BMAD (Baby Methodical Accelerator Design) is presented as an additional tool in creating and simulating accelerator lattices for the studymore » of beam dynamics in the Relativistic Heavy Ion Collider (RHIC).« less

Effect of design over-all compressor pressure ratio division on acceleration characteristics of three hypothetical two-spool turbojet engines

NASA Technical Reports Server (NTRS)

Filippi, Richard E; Dugan, James F , Jr

1956-01-01

The engines, each with a compressor overall total-pressure ratio of 12 and a design inner-turbine-inlet temperature of 2500 degrees R, were investigated at static sea-level conditions to determine the effect on transient performance of varying the desitn pressure ratio divisions 2-6, 3-4, and 4-3 between the outer and inner compressors. The transient considered was an acceleration from 40 to 100 percent design thrust. When the outer compressor of each engine reached design speed, the inner compressors were overspeeding, the maximum being only 1.7 over design mechanical speed. Acceleration times for the three engines were equal.

Cosmic reionization on computers. Mean and fluctuating redshifted 21 CM signal

DOE PAGES

Kaurov, Alexander A.; Gnedin, Nickolay Y.

2016-06-20

We explore the mean and fluctuating redshifted 21 cm signal in numerical simulations from the Cosmic Reionization On Computers project. We find that the mean signal varies between about ±25 mK. Most significantly, we find that the negative pre-reionization dip at z ~ 10–15 only extends tomore » $$\\langle {\\rm{\\Delta }}{T}_{B}\\rangle \\sim -25\\,{\\rm{mK}}$$, requiring substantially higher sensitivity from global signal experiments that operate in this redshift range (EDGES-II, LEDA, SCI-HI, and DARE) than has often been assumed previously. We also explore the role of dense substructure (filaments and embedded galaxies) in the formation of the 21 cm power spectrum. We find that by neglecting the semi-neutral substructure inside ionized bubbles, the power spectrum can be misestimated by 25%–50% at scales k ~ 0.1–1h Mpc –1. Furthermore, this scale range is of particular interest, because the upcoming 21 cm experiments (Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization, Hydrogen Epoch of Reionization Array) are expected to be most sensitive within it.« less

Astronomical Surveys, Catalogs, Databases, and Archives

NASA Astrophysics Data System (ADS)

Mickaelian, A. M.

2016-06-01

All-sky and large-area astronomical surveys and their cataloged data over the whole range of electromagnetic spectrum are reviewed, from γ-ray to radio, such as Fermi-GLAST and INTEGRAL in γ-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). Most important astronomical databases and archives are reviewed as well, including Wide-Field Plate DataBase (WFPDB), ESO, HEASARC, IRSA and MAST archives, CDS SIMBAD, VizieR and Aladin, NED and HyperLEDA extragalactic databases, ADS and astro-ph services. They are powerful sources for many-sided efficient research using Virtual Observatory tools. Using and analysis of Big Data accumulated in astronomy lead to many new discoveries.

Cosmic Reionization On Computers. Mean and Fluctuating Redshifted 21 cm Signal

NASA Astrophysics Data System (ADS)

Kaurov, Alexander A.; Gnedin, Nickolay Y.

2016-06-01

We explore the mean and fluctuating redshifted 21 cm signal in numerical simulations from the Cosmic Reionization On Computers project. We find that the mean signal varies between about ±25 mK. Most significantly, we find that the negative pre-reionization dip at z ˜ 10-15 only extends to < {{Δ }}{T}B> ˜ -25 {{mK}}, requiring substantially higher sensitivity from global signal experiments that operate in this redshift range (EDGES-II, LEDA, SCI-HI, and DARE) than has often been assumed previously. We also explore the role of dense substructure (filaments and embedded galaxies) in the formation of the 21 cm power spectrum. We find that by neglecting the semi-neutral substructure inside ionized bubbles, the power spectrum can be misestimated by 25%-50% at scales k ˜ 0.1-1h Mpc-1. This scale range is of particular interest, because the upcoming 21 cm experiments (Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization, Hydrogen Epoch of Reionization Array) are expected to be most sensitive within it.

Gas-drag-assisted capture of Himalia's family

NASA Astrophysics Data System (ADS)

Ćuk, Matija; Burns, Joseph A.

2004-02-01

To elucidate the capture of Jupiter's outer moons, we reverse-evolve satellites from their present orbits to their original heliocentric paths in the presence of Jupiter's primordial circumplanetary disk (Lubow et al., 1999, Astrophys. J. 526, 1001-1012; Canup and Ward, 2003, Astron. J. 124, 3404-3423). Our orbital histories use a symplectic integrator that allows dissipation. We assume that the present satellites Himalia, Elara, Lysithea, Leda, and S/2000 J11 are collisional fragments of a single parent. Our simulations show that this "prograde-cluster progenitor" (PCP) could be derived from objects with heliocentric orbits like those of the Hilda asteroid group. We show analytically that this capture is energetically possible. We also compare the spectroscopic characteristics of the prograde cluster members (Grav et al., 2003, Icarus, submitted for publication) with those of the Hildas, and conclude that the surface color of the prograde-cluster progenitor is consistent with an origin within the Hilda group. Accordingly, gas drag in the primordial jovian nebula is found to offer a plausible explanation for the origin of the prograde cluster. A similar capture mechanism is proposed for Saturn's Phoebe.

Cosmic reionization on computers. Mean and fluctuating redshifted 21 CM signal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaurov, Alexander A.; Gnedin, Nickolay Y.

We explore the mean and fluctuating redshifted 21 cm signal in numerical simulations from the Cosmic Reionization On Computers project. We find that the mean signal varies between about ±25 mK. Most significantly, we find that the negative pre-reionization dip at z ~ 10–15 only extends tomore » $$\\langle {\\rm{\\Delta }}{T}_{B}\\rangle \\sim -25\\,{\\rm{mK}}$$, requiring substantially higher sensitivity from global signal experiments that operate in this redshift range (EDGES-II, LEDA, SCI-HI, and DARE) than has often been assumed previously. We also explore the role of dense substructure (filaments and embedded galaxies) in the formation of the 21 cm power spectrum. We find that by neglecting the semi-neutral substructure inside ionized bubbles, the power spectrum can be misestimated by 25%–50% at scales k ~ 0.1–1h Mpc –1. Furthermore, this scale range is of particular interest, because the upcoming 21 cm experiments (Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization, Hydrogen Epoch of Reionization Array) are expected to be most sensitive within it.« less

Object-oriented design for accelerator control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stok, P.D.V. van der; Berk, F. van den; Deckers, R.

1994-02-01

An object-oriented design for the distributed computer control system of the accelerator ring EUTERPE is presented. Because of the experimental nature of the ring, flexibility is of the utmost importance. The object-oriented principles have contributed considerably to the flexibility of the design incorporating multiple views, multi-level access and distributed surveillance.

Los Alamos high-power proton linac designs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, G.P.

1995-10-01

Medium-energy high-power proton linear accelerators have been studied at Los Alamos as drivers for spallation neutron applications requiring large amounts of beam power. Reference designs for such accelerators are discussed, important design factors are reviewed, and issues and concern specific to this unprecedented power regime are discussed.

Hardware acceleration and verification of systems designed with hardware description languages (HDL)

NASA Astrophysics Data System (ADS)

Wisniewski, Remigiusz; Wegrzyn, Marek

2005-02-01

Hardware description languages (HDLs) allow creating bigger and bigger designs nowadays. The size of prototyped systems very often exceeds million gates. Therefore verification process of the designs takes several hours or even days. The solution for this problem can be solved by hardware acceleration of simulation.

Design of a Microwave Assisted Discharge Inductive Plasma Accelerator

NASA Technical Reports Server (NTRS)

Hallock, Ashley K.; Polzin, Kurt A.

2010-01-01

A new plasma accelerator concept that employs electrodeless plasma preionization and pulsed inductive acceleration is presented. Preionization is achieved through an electron cyclotron resonance discharge that produces a weakly-ionized plasma at the face of a conical theta pinch-shaped inductive coil. The presence of the preionized plasma allows for current sheet formation at lower discharge voltages than those found in other pulsed inductive accelerators. The location of an electron cyclotron resonance discharge can be controlled through the design of the applied magnetic field in the thruster. A finite-element model of the magnetic field was used as a design tool, allowing for the implementation of an arrangement of permanent magnets that yields a small volume of preionized propellant at the coil face. This allows for current sheet formation at the face of the inductive coil, minimizing the initial inductance of the pulse circuit and maximizing the potential efficiency of the new accelerator.

Designing a Dielectric Laser Accelerator on a Chip

NASA Astrophysics Data System (ADS)

Niedermayer, Uwe; Boine-Frankenheim, Oliver; Egenolf, Thilo

2017-07-01

Dielectric Laser Acceleration (DLA) achieves gradients of more than 1GeV/m, which are among the highest in non-plasma accelerators. The long-term goal of the ACHIP collaboration is to provide relativistic (>1 MeV) electrons by means of a laser driven microchip accelerator. Examples of ’’slightly resonant” dielectric structures showing gradients in the range of 70% of the incident laser field (1 GV/m) for electrons with beta=0.32 and 200% for beta=0.91 are presented. We demonstrate the bunching and acceleration of low energy electrons in dedicated ballistic buncher and velocity matched grating structures. However, the design gradient of 500 MeV/m leads to rapid defocusing. Therefore we present a scheme to bunch the beam in stages, which does not only reduce the energy spread, but also the transverse defocusing. The designs are made with a dedicated homemade 6D particle tracking code.

3D printing of gas jet nozzles for laser-plasma accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Döpp, A.; Guillaume, E.; Thaury, C.

2016-07-15

Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we havemore » used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the SALLE JAUNE terawatt laser at Laboratoire d’Optique Appliquée.« less

Advanced induction accelerator designs for ground based and space based FELs

NASA Astrophysics Data System (ADS)

Birx, Daniel

1994-04-01

The primary goal of this program was to improve the performance of induction accelerators with particular regards to their being used to drive Free Electron Lasers (FEL's). It is hoped that FEL's operating at visible wavelengths might someday be used to beam power from earth to extraterrestrial locations. One application of this technology might be strategic theater defense, but this power source might be used to propel vehicles or supplement solar energized systems. Our path toward achieving this goal was directed first toward optimization of the nonlinear magnetic material used in induction accelerator construction and secondly at the overall design in terms of cost, size and efficiency. We began this research effort with an in depth study into the properties of various nonlinear magnetic materials. With the data on nonlinear magnetic materials, so important to the optimization of efficiency, in hand, we envisioned a new induction accelerator design where all of the components were packaged together in one container. This induction accelerator module would combine an /ll-solid-state, nonlinear magnetic driver and the induction accelerator cells all in one convenient package. Each accelerator module (denoted SNOMAD-IVB) would produce 1.0 MeV of acceleration with the exception of the SNOMAD-IV injector module which would produce 0.5 MeV of acceleration for an electron beam current up to 1000 amperes.

Scaling of induction-cell transverse impedance: effect on accelerator design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ekdahl, Carl August

2016-08-09

The strength of the dangerous beam breakup (BBU) instability in linear induction accelerators (LIAs) is characterized by the transverse coupling impedance Z ⊥. This note addresses the dimensional scaling of Z ⊥, which is important when comparing new LIA designs to existing accelerators with known i BBU growth. Moreover, it is shown that the scaling of Z ⊥ with the accelerating gap size relates BBU growth directly to high-voltage engineering considerations. It is proposed to firmly establish this scaling though a series of AMOS calculations.

Laser ion source for heavy ion inertial fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okamura, Masahiro

The proposed heavy ion inertial fusion (HIF) scenarios require ampere class low charge state ion beams of heavy species. A laser ion source (LIS) is recognized as one of the promising candidates of ion beam providers, since it can deliver high brightness heavy ion beams to accelerators. A design of LIS for the HIF depends on the accelerator structure and accelerator complex following the source. In this article, we discuss the specifications and design of an appropriate LIS assuming two major types of the accelerators: radio frequency (RF) high quality factor cavity type and non-resonant induction core type. We believemore » that a properly designed LIS satisfies the requirements of both types, however some issues need to be verified experimentally.« less

Laser ion source for heavy ion inertial fusion

DOE PAGES

Okamura, Masahiro

2018-01-10

The proposed heavy ion inertial fusion (HIF) scenarios require ampere class low charge state ion beams of heavy species. A laser ion source (LIS) is recognized as one of the promising candidates of ion beam providers, since it can deliver high brightness heavy ion beams to accelerators. A design of LIS for the HIF depends on the accelerator structure and accelerator complex following the source. In this article, we discuss the specifications and design of an appropriate LIS assuming two major types of the accelerators: radio frequency (RF) high quality factor cavity type and non-resonant induction core type. We believemore » that a properly designed LIS satisfies the requirements of both types, however some issues need to be verified experimentally.« less

Optimization of a Small Scale Linear Reluctance Accelerator

NASA Astrophysics Data System (ADS)

Barrera, Thor; Beard, Robby

2011-11-01

Reluctance accelerators are extremely promising future methods of transportation. Several problems still plague these devices, most prominently low efficiency. Variables to overcoming efficiency problems are many and difficult to correlate how they affect our accelerator. The study examined several differing variables that present potential challenges in optimizing the efficiency of reluctance accelerators. These include coil and projectile design, power supplies, switching, and the elusive gradient inductance problem. Extensive research in these areas has been performed from computational and theoretical to experimental. Findings show that these parameters share significant similarity to transformer design elements, thus general findings show current optimized parameters the research suggests as a baseline for further research and design. Demonstration of these current findings will be offered at the time of presentation.

Marker-free transgenic rice expressing the vegetative insecticidal protein (Vip) of Bacillus thuringiensis shows broad insecticidal properties.

PubMed

Pradhan, Subrata; Chakraborty, Anirban; Sikdar, Narattam; Chakraborty, Saikat; Bhattacharyya, Jagannath; Mitra, Joy; Manna, Anulina; Dutta Gupta, Snehasish; Sen, Soumitra Kumar

2016-10-01

Genetically engineered rice lines with broad insecticidal properties against major lepidopteran pests were generated using a synthetic, truncated form of vegetative insecticidal protein (Syn vip3BR) from Bacillus thuringiensis. The selectable marker gene and the redundant transgene(s) were eliminated through Cre/ lox mediated recombination and genetic segregation to make consumer friendly Bt -rice. For sustainable resistance against lepidopteran insect pests, chloroplast targeted synthetic version of bioactive core component of a vegetative insecticidal protein (Syn vip3BR) of Bacillus thuringiensis was expressed in rice under the control of green-tissue specific ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit gene promoter. The transgenic plants (in Oryza sativa indica Swarna cultivar) showed high insect mortality rate in vitro against major rice pests, yellow stem borer (Scirpophaga incertulas), rice leaf folder (Cnaphalocrocis medinalis) and rice horn caterpillar (Melanitis leda ismene) in T1 generation, indicating insecticidal potency of Syn vip3BR. Under field conditions, the T1 plants showed considerable resistance against leaf folders and stem borers. The expression cassette (vip-lox-hpt-lox) as well as another vector with chimeric cre recombinase gene under constitutive rice ubiquitin1 gene promoter was designed for the elimination of selectable marker hygromycin phosphotransferase (hptII) gene. Crossing experiments were performed between T1 plants with single insertion site of vip-lox-hpt-lox T-DNA and one T1 plant with moderate expression of cre recombinase with linked bialaphos resistance (syn bar) gene. Marker gene excision was achieved in hybrids with up to 41.18 % recombination efficiency. Insect resistant transgenic lines, devoid of selectable marker and redundant transgene(s) (hptII + cre-syn bar), were established in subsequent generation through genetic segregation.

Shielding analyses for repetitive high energy pulsed power accelerators

NASA Astrophysics Data System (ADS)

Jow, H. N.; Rao, D. V.

Sandia National Laboratories (SNL) designs, tests and operates a variety of accelerators that generate large amounts of high energy Bremsstrahlung radiation over an extended time. Typically, groups of similar accelerators are housed in a large building that is inaccessible to the general public. To facilitate independent operation of each accelerator, test cells are constructed around each accelerator to shield it from the radiation workers occupying surrounding test cells and work-areas. These test cells, about 9 ft. high, are constructed of high density concrete block walls that provide direct radiation shielding. Above the target areas (radiation sources), lead or steel plates are used to minimize skyshine radiation. Space, accessibility and cost considerations impose certain restrictions on the design of these test cells. SNL Health Physics division is tasked to evaluate the adequacy of each test cell design and compare resultant dose rates with the design criteria stated in DOE Order 5480.11. In response, SNL Health Physics has undertaken an intensive effort to assess existing radiation shielding codes and compare their predictions against measured dose rates. This paper provides a summary of the effort and its results.

Design of Octupole Channel for Integrable Optics Test Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antipov, Sergey; Carlson, Kermit; Castellotti, Riccardo

We present the design of octupole channel for Integrable Optics Test Accelerator (IOTA). IOTA is a test accelerator at Fermilab, aimed to conduct research towards high-intensity machines. One of the goals of the project is to demonstrate high nonlinear betatron tune shifts while retaining large dynamic aperture in a realistic accelerator design. At the first stage the tune shift will be attained with a special channel of octupoles, which creates a variable octupole potential over a 1.8 m length. The channel consists of 18 identical air-cooled octupole magnets. The magnets feature a simple low-cost design, while meeting the requirements onmore » maximum gradient - up to 1.4 kG/cm³, and field quality - strength of harmonics below 1%. Numerical simulations show that the channel is capable of producing a nonlinear tune shift of 0.08 without restriction of dynamic aperture of the ring.« less

Designing Instruction for Speed: Qualitative Insights into Instructional Design for Accelerated Online Graduate Coursework

ERIC Educational Resources Information Center

Trekles, Anastasia M.; Sims, Roderick

2013-01-01

The purpose of this exploratory case study was to explore instructional design strategies and characteristics of online, asynchronous accelerated courses and students' choices of deep or surface learning approaches within this environment. An increasing number of university programs, particularly at the graduate level, are moving to an…

78 FR 38349 - Draft Guidance for Industry on Expedited Programs for Serious Conditions-Drugs and Biologics...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-26

... approval, and priority review designation. DATES: Although you can comment on any guidance at any time (see... designation, (3) accelerated approval, and (4) priority review designation. The draft guidance describes... (the FD&C Act) (Enhancement of Accelerated Approval Access to New Medical Treatments) within 1 year of...

Compliance by Design: Influence of Acceleration Trade-offs on CO2 Emissions and Costs of Fuel Economy and Greenhouse Gas Regulations.

PubMed

Whitefoot, Kate S; Fowlie, Meredith L; Skerlos, Steven J

2017-09-19

The ability of automakers to improve the fuel economy of vehicles using engineering design modifications that compromise other performance attributes, such as acceleration, is not currently considered when setting fuel economy and greenhouse-gas emission standards for passenger cars and light trucks. We examine the role of these design trade-offs by simulating automaker responses to recently reformed vehicle standards with and without the ability to adjust acceleration performance. Results indicate that acceleration trade-offs can be important in two respects: (1) they can reduce the compliance costs of the standards, and (2) they can significantly reduce emissions associated with a particular level of the standards by mitigating incentives to shift sales toward larger vehicles and light trucks relative to passenger cars. We contrast simulation-based results with observed changes in vehicle attributes under the reformed standards. We find evidence that is consistent with firms using acceleration trade-offs to achieve compliance. Taken together, our analysis suggests that acceleration trade-offs play a role in automaker compliance strategies with potentially large implications for both compliance costs and emissions.

Conceptual design of a high real-estate gradient cavity for a SRF ERL

NASA Astrophysics Data System (ADS)

Xu, Chen; Ben-Zvi, Ilan; Hao, Yue; Xin, Tianmu; Wang, Haipeng

2017-10-01

The term "real-estate gradient" is used to describe the energy gain provided by an accelerating structure per actual length it takes in the accelerator. given that the length of the tunnel available for the accelerator is constrained, the real-estate gradient is an important measure of the efficiency of a given accelerator structure. When designing an accelerating cavity to be efficient in this sense, the unwanted Higher Order Mode (HOM) fields should be reduced by suitable HOM dampers. This is a particularly important consideration for high current operation. The additional RF components might take longitude space and reduce the total accelerating efficiency. We describe a new high efficiency 5-cell cavity with the dampers included. The total length of the cavity is reduced by 13% as compared to a more conventional design without compromising the cavity fundamental-mode performance. In addition, the HOM impedance is reduced for a higher Beam-Break-Up (BBU) threshold of operating current. In this paper, we consider an example, a possible application at the eRHIC Energy Recovery Linac (ERL).

Optimal Control Design using an H(sub 2) Method for the Glovebox Integrated Microgravity Isolation Technology (G-Limit)

NASA Technical Reports Server (NTRS)

Calhoun, Philip C.; Hampton, R. David

2002-01-01

The acceleration environment on the International Space Station (ISS) will likely exceed the requirements of many micro-gravity experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) is being built by the NASA Marshall Space Flight Center to attenuate the nominal acceleration environment and provide some isolation for microgravity science experiments. G-LIMIT uses Lorentz (voice-coil) magnetic actuators to isolate a platform for mounting science payloads from the nominal acceleration environment. The system utilizes payload acceleration, relative position, and relative orientation measurements in a feedback controller to accomplish the vibration isolation task. The controller provides current commands to six magnetic actuators, producing the required experiment isolation from the ISS acceleration environment. This paper presents the development of a candidate control law to meet the acceleration attenuation requirements for the g-LIMIT experiment platform. The controller design is developed using linear optimal control techniques for frequency-weighted H(sub 2) norms. Comparison of the performance and robustness to plant uncertainty for this control design approach is included in the discussion.

Frequency Weighted H2 Control Design for the Glovebox Integrated Microgravity Isolation Technology (g-LIMIT)

NASA Technical Reports Server (NTRS)

Calhoun, Philip C.; Hampton, R. David

2004-01-01

The acceleration environment on the International Space Station (ISS) exceeds the requirements of many microgravity experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) has been built by the NASA Marshall Space Flight Center to attenuate the nominal acceleration environment and provide some isolation for microgravity science experiments. The g-LIMIT uses Lorentz (voice-coil) magnetic actuators to isolate a platform, for mounting science payloads, from the nominal acceleration environment. The system utilizes payload-acceleration, relative-position, and relative-orientation measurements in a feedback controller to accomplish the vibration isolation task. The controller provides current commands to six magnetic actuators, producing the required experiment isolation from the ISS acceleration environment. The present work documents the development of a candidate control law to meet the acceleration attenuation requirements for the g-LIMIT experiment platform. The controller design is developed using linear optimal control techniques for frequency-weighted H2 norms. Comparison of performance and robustness to plant uncertainty for this control design approach is included in the discussion. System performance is demonstrated in the presence of plant modeling error.

Optimal Control Design Using an H2 Method for the Glovebox Integrated Microgravity Isolation Technology (g-LIMIT)

NASA Technical Reports Server (NTRS)

Calhoun, Phillip C.; Hampton, R. David; Whorton, Mark S.

2001-01-01

The acceleration environment on the International Space Station (ISS) will likely exceed the requirements of many micro-gravity experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) is being built by the NASA Marshall Space Flight Center to attenuate the nominal acceleration environment and provide some isolation for micro-gravity science experiments. G-LIMIT uses Lorentz (voice-coil) magnetic actuators to isolate a platform for mounting science payloads from the nominal acceleration environment. The system utilizes payload acceleration, relative position, and relative orientation measurements in a feedback controller to accomplish the vibration isolation task. The controller provides current command to six magnetic actuators, producing the required experiment isolation from the ISS acceleration environment. This paper presents the development of a candidate control law to meet the acceleration attenuation requirements for the g-LIMIT experiment platform. The controller design is developed using linear optimal control techniques for both frequency-weighted H(sub 2) and H(sub infinity) norms. Comparison of the performance and robustness to plant uncertainty for these two optimal control design approaches are included in the discussion.

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.

SMART empirical approaches for predicting field performance of PV modules from results of reliability tests

NASA Astrophysics Data System (ADS)

Hardikar, Kedar Y.; Liu, Bill J. J.; Bheemreddy, Venkata

2016-09-01

Gaining an understanding of degradation mechanisms and their characterization are critical in developing relevant accelerated tests to ensure PV module performance warranty over a typical lifetime of 25 years. As newer technologies are adapted for PV, including new PV cell technologies, new packaging materials, and newer product designs, the availability of field data over extended periods of time for product performance assessment cannot be expected within the typical timeframe for business decisions. In this work, to enable product design decisions and product performance assessment for PV modules utilizing newer technologies, Simulation and Mechanism based Accelerated Reliability Testing (SMART) methodology and empirical approaches to predict field performance from accelerated test results are presented. The method is demonstrated for field life assessment of flexible PV modules based on degradation mechanisms observed in two accelerated tests, namely, Damp Heat and Thermal Cycling. The method is based on design of accelerated testing scheme with the intent to develop relevant acceleration factor models. The acceleration factor model is validated by extensive reliability testing under different conditions going beyond the established certification standards. Once the acceleration factor model is validated for the test matrix a modeling scheme is developed to predict field performance from results of accelerated testing for particular failure modes of interest. Further refinement of the model can continue as more field data becomes available. While the demonstration of the method in this work is for thin film flexible PV modules, the framework and methodology can be adapted to other PV products.

The development of enabling technologies for producing active interrogation beams.

PubMed

Kwan, Thomas J T; Morgado, Richard E; Wang, Tai-Sen F; Vodolaga, B; Terekhin, V; Onischenko, L M; Vorozhtsov, S B; Samsonov, E V; Vorozhtsov, A S; Alenitsky, Yu G; Perpelkin, E E; Glazov, A A; Novikov, D L; Parkhomchuk, V; Reva, V; Vostrikov, V; Mashinin, V A; Fedotov, S N; Minayev, S A

2010-10-01

A U.S./Russian collaboration of accelerator scientists was directed to the development of high averaged-current (∼1 mA) and high-quality (emittance ∼15 πmm mrad; energy spread ∼0.1%) 1.75 MeV proton beams to produce active interrogation beams that could be applied to counterterrorism. Several accelerator technologies were investigated. These included an electrostatic tandem accelerator of novel design, a compact cyclotron, and a storage ring with energy compensation and electron cooling. Production targets capable of withstanding the beam power levels were designed, fabricated, and tested. The cyclotron/storage-ring system was theoretically studied and computationally designed, and the electrostatic vacuum tandem accelerator at BINP was demonstrated for its potential in active interrogation of explosives and special nuclear materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Alex; Bruning, Oliver; Cruz-Alaniz, E.

Unprecedently high luminosity of 10 34 cm -2 s -1, promised by the LHeC accelerator complex poses several beam dynamics and lattice design challenges. As part of accelerator design process, exploration of innovative beam dynamics solutions and their lattice implementations is the key to mitigating performance limitations due to fundamental beam phenomena, such as: synchrotron radiation and collective instabilities. This article will present beam dynamics driven approach to accelerator design, which in particular, addresses emittance dilution due to quantum excitations and beam breakup instability in a large scale, multi-pass Energy Recovery Linac (ERL). The use of ERL accelerator technology tomore » provide improved beam quality and higher brightness continues to be the subject of active community interest and active accelerator development of future Electron Ion Colliders (EIC). Here, we employ current state of though for ERLs aiming at the energy frontier EIC. We will follow conceptual design options recently identified for the LHeC. The main thrust of these studies was to enhance the collider performance, while limiting overall power consumption through exploring interplay between emittance preservation and efficiencies promised by the ERL technology. Here, this combined with a unique design of the Interaction Region (IR) optics gives the impression that luminosity of 10 34 cm -2 s -1 is indeed feasible.« less

Novel Lattice Solutions for the LHeC

DOE PAGES

Bogacz, Alex; Bruning, Oliver; Cruz-Alaniz, E.; ...

2017-08-01

Unprecedently high luminosity of 10 34 cm -2 s -1, promised by the LHeC accelerator complex poses several beam dynamics and lattice design challenges. As part of accelerator design process, exploration of innovative beam dynamics solutions and their lattice implementations is the key to mitigating performance limitations due to fundamental beam phenomena, such as: synchrotron radiation and collective instabilities. This article will present beam dynamics driven approach to accelerator design, which in particular, addresses emittance dilution due to quantum excitations and beam breakup instability in a large scale, multi-pass Energy Recovery Linac (ERL). The use of ERL accelerator technology tomore » provide improved beam quality and higher brightness continues to be the subject of active community interest and active accelerator development of future Electron Ion Colliders (EIC). Here, we employ current state of though for ERLs aiming at the energy frontier EIC. We will follow conceptual design options recently identified for the LHeC. The main thrust of these studies was to enhance the collider performance, while limiting overall power consumption through exploring interplay between emittance preservation and efficiencies promised by the ERL technology. Here, this combined with a unique design of the Interaction Region (IR) optics gives the impression that luminosity of 10 34 cm -2 s -1 is indeed feasible.« less

An Instructional Design for Accelerating Children's Concept Learning. Technical Report No. 321.

ERIC Educational Resources Information Center

McMurray, Nancy E.; And Others

An instructional design based on task analysis procedures was used to develop two experimental lessons to accelerate attainment of a subject-matter concept by fourth grade students. A variation of the Solomon Four-Group design was employed to determine the effects of the pretest. Performance of 118 randomly assigned subjects on a measure assessing…

Science 101: How Do People Design Safe Amusement Park Rides?

ERIC Educational Resources Information Center

Robertson, Bill

2015-01-01

To address the question of how people design safe amusement park rides, Bill Robertson focuses on the factors designers must consider so that human bodies don't experience too large an acceleration (any change in speed and/or direction) or "g-force" (the acceleration an object undergoes while freely falling, with no air resistance, under…

Development Biology Worksheet Oriented Accelerated Learning on Plantae and Ecosystems for 10th-Grade Senior High School Students

NASA Astrophysics Data System (ADS)

Dipuja, D. A.; Lufri, L.; Ahda, Y.

2018-04-01

The problem that found are learning outcomes student is low on the plantae and ecosystems. Students less motivated and passive learning because learning is teacher center and teaching materials not facilitate student. Therefore, it is necessary to design a worksheet oriented accelerated learning. Accelerated learning approach that can improve motivation and learning activities. The purpose of the research was to produce worksheet oriented accelerated learning on plantae and ecosystems. This research is designed as a research and development by using Plomp model, consists of the preliminary, prototyping, and assessment phase. Data was collected through questionnaires, observation sheet, test, and documentation. The results of the research was worksheet oriented accelerated learning on plantae and ecosystems is very valid.

Generation and application of ultrashort coherent mid-infrared electromagnetic radiation

NASA Astrophysics Data System (ADS)

Wandel, Scott

Particle accelerators are useful instruments that help address critical issues for the future development of nuclear energy. Current state-of-the-art accelerators based on conventional radio-frequency (rf) cavities are too large and expensive for widespread commercial use, and alternative designs must be considered for supplying relativistic beams to small-scale applications, including medical imaging, secu- rity screening, and scientific research in a university-scale laboratory. Laser-driven acceleration using micro-fabricated dielectric photonic structures is an attractive approach because such photonic microstructures can support accelerating fields that are 10 to 100 times higher than that of rf cavity-based accelerators. Dielectric laser accelerators (DLAs) use commercial lasers as a driving source, which are smaller and less expensive than the klystrons used to drive current rf-based accelerators. Despite the apparent need for compact and economical laser sources for laser-driven acceleration, the availability of suitable high-peak-power lasers that cover a broad spectral range is currently limited. To address the needs of several innovative acceleration mechanisms like DLA, it is proposed to develop a coherent source of mid-infrared (IR) electromagnetic radiation that can be implemented as a driving source of laser accelerators. The use of ultrashort mid-IR high peak power laser systems in various laser-driven acceleration schemes has shown the potential to greatly reduce the optical pump intensities needed to realize high acceleration gradients. The optical intensity needed to achieve a given ponderomotive potential is 25 times less when using a 5-mum mid-IR laser as compared to using a 1-mum near-IR solid-state laser. In addition, dielectric structure breakdown caused by multiphoton ionization can be avoided by using longer-wavelength driving lasers. Current mid-IR laser sources do not produce sufficiently short pulse durations, broad spectral bandwidths, or high energies as required by certain accelerator applications. The use of a high-peak-power mid-IR laser system in DLA could enable tabletop accelerators on the MeV to GeV scale for security scanners, medical therapy devices, and compact x-ray light sources. This dissertation reports on the design and construction of a simple and robust, short-pulse parametric source operating at a center wavelength of 5 mum. The design and construction of a high-energy, short-pulse 2-mum parametric source is also presented, which serves as a surrogate pumping source for the 5-mum source. An elegant method for mid-IR pulse characterization is demonstrated, which makes use of ubiquitous silicon photodetectors, traditionally reserved for the characterization of near-IR radiation. In addition, a dual-chirped parametric amplification technique is extended into the mid-IR spectral region, producing a bandwidth-tunable mid-IR source in a simple design without sacrificing conversion efficiency. The design and development of a compact single-shot mid-IR prism spectrometer is also reported, and its implementation in a number of condensed matter studies at the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center is discussed. Rapid tuning and optimization of a high-energy parametric laser system using the mid-IR spectrometer is demonstrated, which significantly enhances the capabilities of performing optical measurements on superconducting materials using the LCLS instrument. All of the laser sources and optical technologies presented in this dissertation were developed using relatively simple designs to provide compact and cost-e ective systems to address some of the challenges facing accelerator and IR spectroscopy technologies. (Abstract shortened by ProQuest.).

A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

NASA Astrophysics Data System (ADS)

Wu, Fengjun; Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen; Cui, Yuan; Yan, Hongbin; Zhang, Huajian; Wang, Bin; Li, Xiaohui

2016-08-01

To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply.

MAPA: Implementation of the Standard Interchange Format and use for analyzing lattices

NASA Astrophysics Data System (ADS)

Shasharina, Svetlana G.; Cary, John R.

1997-05-01

MAPA (Modular Accelerator Physics Analysis) is an object oriented application for accelerator design and analysis with a Motif based graphical user interface. MAPA has been ported to AIX, Linux, HPUX, Solaris, and IRIX. MAPA provides an intuitive environment for accelerator study and design. The user can bring up windows for fully nonlinear analysis of accelerator lattices in any number of dimensions. The current graphical analysis methods of Lifetime plots and Surfaces of Section have been used to analyze the improved lattice designs of Wan, Cary, and Shasharina (this conference). MAPA can now read and write Standard Interchange Format (MAD) accelerator description files and it has a general graphical user interface for adding, changing, and deleting elements. MAPA's consistency checks prevent deletion of used elements and prevent creation of recursive beam lines. Plans include development of a richer set of modeling tools and the ability to invoke existing modeling codes through the MAPA interface. MAPA will be demonstrated on a Pentium 150 laptop running Linux.

[A study of magnetic shielding design for a magnetic resonance imaging linac system].

PubMed

Zhang, Zheshun; Chen, Wenjing; Qiu, Yang; Zhu, Jianming

2017-12-01

One of the main technical challenges when integrating magnetic resonance imaging (MRI) systems with medical linear accelerator is the strong interference of fringe magnetic fields from the MRI system with the electron beams of linear accelerator, making the linear accelerator not to work properly. In order to minimize the interference of magnetic fields, a magnetic shielding cylinder with an open structure made of high permeability materials is designed. ANSYS Maxwell was used to simulate Helmholtz coil which generate uniform magnetic field instead of the fringe magnetic fields which affect accelerator gun. The parameters of shielding tube, such as permeability, radius, length, side thickness, bottom thickness and fringe magnetic fields strength are simulated, and the data is processed by MATLAB to compare the shielding performance. This article gives out a list of magnetic shielding effectiveness with different side thickness and bottom thickness under the optimal radius and length, which showes that this design can meet the shielding requirement for the MRI-linear accelerator system.

Method for computationally efficient design of dielectric laser accelerator structures

DOE PAGES

Hughes, Tyler; Veronis, Georgios; Wootton, Kent P.; ...

2017-06-22

Here, dielectric microstructures have generated much interest in recent years as a means of accelerating charged particles when powered by solid state lasers. The acceleration gradient (or particle energy gain per unit length) is an important figure of merit. To design structures with high acceleration gradients, we explore the adjoint variable method, a highly efficient technique used to compute the sensitivity of an objective with respect to a large number of parameters. With this formalism, the sensitivity of the acceleration gradient of a dielectric structure with respect to its entire spatial permittivity distribution is calculated by the use of onlymore » two full-field electromagnetic simulations, the original and ‘adjoint’. The adjoint simulation corresponds physically to the reciprocal situation of a point charge moving through the accelerator gap and radiating. Using this formalism, we perform numerical optimizations aimed at maximizing acceleration gradients, which generate fabricable structures of greatly improved performance in comparison to previously examined geometries.« less

Compact Plasma Accelerator

NASA Technical Reports Server (NTRS)

Foster, John E.

2004-01-01

A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

A new compact structure for a high intensity low-energy heavy-ion accelerator

NASA Astrophysics Data System (ADS)

Wang, Zhi-Jun; He, Yuan; A. Kolomiets, A.; Liu, Shu-Hui; Du, Xiao-Nan; Jia, Huan; Li, Chao; Wang, Wang-Sheng; Chen, Xi-Meng

2013-12-01

A new compact accelerating structure named Hybrid RFQ is proposed to accelerate a high-intensity low-energy heavy ion beam in HISCL (High Intensive heavy ion SuperConducting Linear accelerator), which is an injector of HIAF (Heavy Ion Advanced Research Facility). It is combined by an alternative series of acceleration gaps and RFQ sections. The proposed structure has a high accelerating ability compared with a conventional RFQ and is more compact than traditional DTLs. A Hybrid RFQ is designed to accelerate 238U34+ from 0.38 MeV/u to 1.33 MeV/u. The operation frequency is described to be 81.25 MHz at CW (continuous wave) mode. The design beam current is 1.0 mA. The results of beam dynamics and RF simulation of the Hybrid RFQ show that the structure has a good performance at the energy range for ion acceleration. The emittance growth is less than 5% in both directions and the RF power is less than 150 kW. In this paper, the results of beam dynamics and RF simulation of the Hybrid RFQ are presented.

Calibration of a Six-Degree-of-Freedom Acceleration Measurement Device

DOT National Transportation Integrated Search

1994-12-01

This report describes the calibration of a six-degree-of-freedom acceleration measurement system designed for use in the measurement of linear and angular head accelerations of anthropomorphic dummies during crash tests. The calibration methodology, ...

Conceptual design of an intense positron source based on an LIA

NASA Astrophysics Data System (ADS)

Long, Ji-Dong; Yang, Zhen; Dong, Pan; Shi, Jin-Shui

2012-04-01

Accelerator based positron sources are widely used due to their high intensity. Most of these accelerators are RF accelerators. An LIA (linear induction accelerator) is a kind of high current pulsed accelerator used for radiography. A conceptual design of an intense pulsed positron source based on an LIA is presented in the paper. One advantage of an LIA is its pulsed power being higher than conventional accelerators, which means a higher amount of primary electrons for positron generations per pulse. Another advantage of an LIA is that it is very suitable to decelerate the positron bunch generated by bremsstrahlung pair process due to its ability to adjustably shape the voltage pulse. By implementing LIA cavities to decelerate the positron bunch before it is moderated, the positron yield could be greatly increased. These features may make the LIA based positron source become a high intensity pulsed positron source.

Operational and design aspects of accelerators for medical applications

NASA Astrophysics Data System (ADS)

Schippers, Jacobus Maarten; Seidel, Mike

2015-03-01

Originally, the typical particle accelerators as well as their associated beam transport equipment were designed for particle and nuclear physics research and applications in isotope production. In the past few decades, such accelerators and related equipment have also been applied for medical use. This can be in the original physics laboratory environment, but for the past 20 years also in hospital-based or purely clinical environments for particle therapy. The most important specific requirements of accelerators for radiation therapy with protons or ions will be discussed. The focus will be on accelerator design, operational, and formal aspects. We will discuss the special requirements to reach a high reliability for patient treatments as well as an accurate delivery of the dose at the correct position in the patient using modern techniques like pencil beam scanning. It will be shown that the technical requirements, safety aspects, and required reliability of the accelerated beam differ substantially from those in a nuclear physics laboratory. It will be shown that this difference has significant implications on the safety and interlock systems. The operation of such a medical facility should be possible by nonaccelerator specialists at different operating sites (treatment rooms). The organization and role of the control and interlock systems can be considered as being the most crucially important issue, and therefore a special, dedicated design is absolutely necessary in a facility providing particle therapy.

A Comprehensive Investigation and Coupler Design for Higher-Order Modes in the BNL Energy Recovery Linear Accelerator

NASA Astrophysics Data System (ADS)

Marques, Carlos

A next generation Energy Recovery Linac (ERL) is under development in the Collider-Accelerator Department at Brookhaven National Laboratory (BNL). This ERL uses a superconducting radio frequency (SFR) cavity to produce an electric field gradient ideal to accelerate charged particles. As with many accelerators, higher-order modes (HOMs) can be induced by a beam of charged particles traversing the linear accelerator cavity. The excitation of these modes can result in problematic single and multi-bunch effects and also produce undesirable heat loads to the cryogenic system. Understanding HOM prevalence and structure inside the accelerator cavity is crucial for devising a procedure for extracting HOM power and promoting excellent beam quality. In this work, a method was created to identify and characterize HOMs using a perturbation technique on a copper (Cu) cavity prototype of the BNL3 linac and a double lambda/4 crab cavity. Both analyses and correlation between simulated and measured results are shown. A coaxial to dual-ridge waveguide HOM coupler was designed, constructed and implemented to extract power from HOMs simultaneously making an evanescent fundamental mode for the BNL3 cavity. A full description of the design is given along with a simulated analysis of its performance. Comparison between previous HOM coupler designs as well as correspondence between simulation and measurement is also given.

Laboratory-Model Integrated-System FARAD Thruster

NASA Technical Reports Server (NTRS)

Polzin, K.A.; Best, S.; Miller, R.; Rose, M.F.; Owens, T.

2008-01-01

Pulsed inductive plasma accelerators are spacecraft propulsion devices in which energy is stored in a capacitor and then discharged through an inductive coil. The device is electrodeless, inducing a plasma current sheet in propellant located near the face of the coil. The propellant is accelerated and expelled at a high exhaust velocity (order of 10 km/s) through the interaction of the plasma current with an induced magnetic field. The Faraday Accelerator with RF-Assisted Discharge (FARAD) thruster [1,2] is a type of pulsed inductive plasma accelerator in which the plasma is preionized by a mechanism separate from that used to form the current sheet and accelerate the gas. Employing a separate preionization mechanism in this manner allows for the formation of an inductive current sheet at much lower discharge energies and voltages than those found in previous pulsed inductive accelerators like the Pulsed Inductive Thruster (PIT). In a previous paper [3], the authors presented a basic design for a 100 J/pulse FARAD laboratory-version thruster. The design was based upon guidelines and performance scaling parameters presented in Refs. [4, 5]. In this paper, we expand upon the design presented in Ref. [3] by presenting a fully-assembled and operational FARAD laboratory-model thruster and addressing system and subsystem-integration issues (concerning mass injection, preionization, and acceleration) that arose during assembly. Experimental data quantifying the operation of this thruster, including detailed internal plasma measurements, are presented by the authors in a companion paper [6]. The thruster operates by first injecting neutral gas over the face of a flat, inductive acceleration coil and at some later time preionizing the gas. Once the gas is preionized current is passed through the acceleration coil, inducing a plasma current sheet in the propellant that is accelerated away from the coil through electromagnetic interaction with the time-varying magnetic field. Neutral gas is injected over the face of the acceleration coil through a fast-acting valve that feeds a central distribution manifold. The thruster is designed to preionize the gas using an RF-frequency ringing signal produced by a discharging Vector Inversion Generator (VIG). The acceleration stage consists of a multiple-turn, multiple-strand spiral induction coil (see Fig. 1, left panel) and is designed for operation at discharge energies on the order of 100 J/pulse. Several different pulsed power train modules can be used to drive current through the acceleration coil. One such power train is based upon the Bernardes and Merryman circuit topology, which restricts voltage reversal on the capacitor banks and can be clamped to eliminate current reversal in the coil. A second option is a pulse-compression-ring power train (see Fig. 1, right panel), which takesa temporally broad, low current pulse and transforms it into a short, high current pulse.

Induction launcher design considerations

NASA Technical Reports Server (NTRS)

Driga, M. D.; Weldon, W. F.

1989-01-01

New concepts in the design of induction accelerators and their power supplies for space and military applications are discussed. Particular attention is given to a piecewise-rising-frequency power supply in which each elementary generator (normal compulsator or rising frequency generator) has a different base frequency. A preliminary design of a coaxial induction accelerator for a hypersonic real gas facility is discussed to illustrate the concepts described.

Seismic hazard of American Samoa and neighboring South Pacific Islands--methods, data, parameters, and results

USGS Publications Warehouse

Petersen, Mark D.; Harmsen, Stephen C.; Rukstales, Kenneth S.; Mueller, Charles S.; McNamara, Daniel E.; Luco, Nicolas; Walling, Melanie

2012-01-01

American Samoa and the neighboring islands of the South Pacific lie near active tectonic-plate boundaries that host many large earthquakes which can result in strong earthquake shaking and tsunamis. To mitigate earthquake risks from future ground shaking, the Federal Emergency Management Agency requested that the U.S. Geological Survey prepare seismic hazard maps that can be applied in building-design criteria. This Open-File Report describes the data, methods, and parameters used to calculate the seismic shaking hazard as well as the output hazard maps, curves, and deaggregation (disaggregation) information needed for building design. Spectral acceleration hazard for 1 Hertz having a 2-percent probability of exceedance on a firm rock site condition (Vs30=760 meters per second) is 0.12 acceleration of gravity (1 second, 1 Hertz) and 0.32 acceleration of gravity (0.2 seconds, 5 Hertz) on American Samoa, 0.72 acceleration of gravity (1 Hertz) and 2.54 acceleration of gravity (5 Hertz) on Tonga, 0.15 acceleration of gravity (1 Hertz) and 0.55 acceleration of gravity (5 Hertz) on Fiji, and 0.89 acceleration of gravity (1 Hertz) and 2.77 acceleration of gravity (5 Hertz) on the Vanuatu Islands.

Consequences of bounds on longitudinal emittance growth for the design of recirculating linear accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, J. S.

2015-05-03

Recirculating linear accelerators (RLAs) are a cost-effective method for the acceleration of muons for a muon collider in energy ranges from a couple GeV to a few 10s of GeV. Muon beams generally have longitudinal emittances that are large for the RF frequency that is used, and it is important to limit the growth of that longitudinal emittance. This has particular consequences for the arc design of the RLAs. I estimate the longitudinal emittance growth in an RLA arising from the RF nonlinearity. Given an emittance growth limitation and other design parameters, one can then compute the maximum momentum compactionmore » in the arcs. I describe how to obtain an approximate arc design satisfying these requirements based on the deisgn in [1]. Longitudinal dynamics also determine the energy spread in the beam, and this has consequences on the transverse phase advance in the linac. This in turn has consequences for the arc design due to the need to match beta functions. I combine these considerations to discuss design parameters for the acceleration of muons for a collider in an RLA from 5 to 63 GeV.« less

High gradient RF test results of S-band and C-band cavities for medical linear accelerators

NASA Astrophysics Data System (ADS)

Degiovanni, A.; Bonomi, R.; Garlasché, M.; Verdú-Andrés, S.; Wegner, R.; Amaldi, U.

2018-05-01

TERA Foundation has proposed and designed hadrontherapy facilities based on novel linacs, i.e. high gradient linacs which accelerate either protons or light ions. The overall length of the linac, and therefore its cost, is almost inversely proportional to the average accelerating gradient. With the scope of studying the limiting factors for high gradient operation and to optimize the linac design, TERA, in collaboration with the CLIC Structure Development Group, has conducted a series of high gradient experiments. The main goals were to study the high gradient behavior and to evaluate the maximum gradient reached in 3 and 5.7 GHz structures to direct the design of medical accelerators based on high gradient linacs. This paper summarizes the results of the high power tests of 3.0 and 5.7 GHz single-cell cavities.

A preliminary design of the collinear dielectric wakefield accelerator

NASA Astrophysics Data System (ADS)

Zholents, A.; Gai, W.; Doran, S.; Lindberg, R.; Power, J. G.; Strelnikov, N.; Sun, Y.; Trakhtenberg, E.; Vasserman, I.; Jing, C.; Kanareykin, A.; Li, Y.; Gao, Q.; Shchegolkov, D. Y.; Simakov, E. I.

2016-09-01

A preliminary design of the multi-meter long collinear dielectric wakefield accelerator that achieves a highly efficient transfer of the drive bunch energy to the wakefields and to the witness bunch is considered. It is made from 0.5 m long accelerator modules containing a vacuum chamber with dielectric-lined walls, a quadrupole wiggler, an rf coupler, and BPM assembly. The single bunch breakup instability is a major limiting factor for accelerator efficiency, and the BNS damping is applied to obtain the stable multi-meter long propagation of a drive bunch. Numerical simulations using a 6D particle tracking computer code are performed and tolerances to various errors are defined.

Sensitivity of 30-cm mercury bombardment ion thruster characteristics to accelerator grid design

NASA Technical Reports Server (NTRS)

Rawlin, V. K.

1978-01-01

The design of ion optics for bombardment thrusters strongly influences overall performance and lifetime. The operation of a 30 cm thruster with accelerator grid open area fractions ranging from 43 to 24 percent, was evaluated and compared with experimental and theoretical results. Ion optics properties measured included the beam current extraction capability, the minimum accelerator grid voltage to prevent backstreaming, ion beamlet diameter as a function of radial position on the grid and accelerator grid hole diameter, and the high energy, high angle ion beam edge location. Discharge chamber properties evaluated were propellant utilization efficiency, minimum discharge power per beam amp, and minimum discharge voltage.

SU-E-T-512: Electromagnetic Simulations of the Dielectric Wall Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uselmann, A; Mackie, T

Purpose: To characterize and parametrically study the key components of a dielectric wall accelerator through electromagnetic modeling and particle tracking. Methods: Electromagnetic and particle tracking simulations were performed using a commercial code (CST Microwave Studio, CST Inc.) utilizing the finite integration technique. A dielectric wall accelerator consists of a series of stacked transmission lines sequentially fired in synchrony with an ion pulse. Numerous properties of the stacked transmission lines, including geometric, material, and electronic properties, were analyzed and varied in order to assess their impact on the transverse and axial electric fields. Additionally, stacks of transmission lines were simulated inmore » order to quantify the parasitic effect observed in closely packed lines. Particle tracking simulations using the particle-in-cell method were performed on the various stacks to determine the impact of the above properties on the resultant phase space of the ions. Results: Examination of the simulation results show that novel geometries can shape the accelerating pulse in order to reduce the energy spread and increase the average energy of accelerated ions. Parasitic effects were quantified for various geometries and found to vary with distance from the end of the transmission line and along the beam axis. An optimal arrival time of an ion pulse relative to the triggering of the transmission lines for a given geometry was determined through parametric study. Benchmark simulations of single transmission lines agree well with published experimental results. Conclusion: This work characterized the behavior of the transmission lines used in a dielectric wall accelerator and used this information to improve them in novel ways. Utilizing novel geometries, we were able to improve the accelerating gradient and phase space of the accelerated particle bunch. Through simulation, we were able to discover and optimize design issues with the device at low cost. Funding: Morgridge Institute for Research, Madison WI; Conflict of Interest: Dr. Mackie is an investor and board member at CPAC, a company developing compact accelerator designs similar to those discussed in this work, but designs discussed are not directed by CPAC. Funding: Morgridge Institute for Research, Madison WI; Conflict of Interest: Dr. Mackie is an investor and board member at CPAC, a company developing compact accelerator designs similar to those discussed in this work, but designs discussed are not directed by CPAC.« less

Design of an Integrated-System FARAD Thruster

NASA Technical Reports Server (NTRS)

Polzin, K.A.; Rose, R.F.; Miller, R.; Owens, T.

2007-01-01

Pulsed inductive plasma accelerators are spacecraft propulsion devices in which energy is stored in a capacitor and then discharged through an inductive coil. The device is electrodeless, inducing a current s heet in a plasma located near the face of the coil. The propellant is accelerated and expelled at a high exhaust velocity (order of 10 km/s) through the interaction of the plasma current and the induced magne tic field, The Faraday Accelerator with RF-Assisted Discharge (FARAD) thruster is a type of pulsed inductive plasma accelerator in which t he plasma is preionized by a mechanism separate from that used to for m the current sheet and accelerate the gas. Employing a separate preionization mechanism allows for the formation of an inductive current s heet at much lower discharge energies and voltages than those used in previous pulsed inductive accelerators like the Pulsed Inductive Thr uster (PIT). In this paper, we present the design of a benchtop FARAD thruster with all the subsystems (mass injection, preionization, and acceleration) integrated into a single unit. Design of the thruster follows the guidelines and similarity performance parameters presented elsewhere. The system is designed to use the ringing, RF-frequency s ignal produced by a discharging Vector Inversion Generator (VIG) to p reionize the gas. The acceleration stage operates on the order of 100 J/pulse and can be driven by several different pulsed powertrains. These include a simple capacitor coupled to the system, a Bernardes and Merryman configuration, and a pulsecompression circuit that takes a temporally broad, low current pulse and transforms it into a short, h igh current pulse. A set of applied magnetic field coils are integrated into the system to guide the preionized propellant as it spreads ov er the face of the inductive acceleration coil. The coils are operate d in a pulsed mode, and the thruster can be operated without using the coils to determine if there is a performance improvement gain realiz ed when an applied field is present.

Accelerated testing for studying pavement design and performance (FY 2003) : research summary.

DOT National Transportation Integrated Search

2008-01-01

The Midwest States Accelerated Pavement Testing Pooled Fund Program, financed by : the highway departments of Missouri, Iowa, Kansas and Nebraska, has supported an : accelerated pavement testing (APT) project to compare the performance of stabilized ...

Preliminary design of a high-intensity continuous-wave deuteron RFQ

NASA Astrophysics Data System (ADS)

Liu, X.; Kamigaito, O.; Sakamoto, N.; Yamada, K.

2017-07-01

A high-intensity deuteron linear accelerator is currently being studied as a promising candidate to treat high-level radioactive waste through the nuclear transmutation process. This paper presents the study on a design of a 75.5 MHz, 400 mA, continuous-wave deuteron radio-frequency quadrupole (RFQ), which is proposed as the front-end of such a linear accelerator. The results of the beam dynamics simulation suggest that the designed RFQ can accelerate a 400-mA deuteron beam from 100 keV to 2.5 MeV with a transmission rate of 92.0 ∼ 93.3%, depending on the assumed input transverse emittance.

Design of an upgradeable 45-100 mA RFQ accelerator for FAIR

NASA Astrophysics Data System (ADS)

Zhang, Chuan; Schempp, Alwin

2009-10-01

A 325 MHz, 35 mA, 3 MeV Radio-Frequency Quadrupole (RFQ) accelerator will be operated as the first accelerating structure of the proton linac injector for the newly planned international science center Facility for Antiproton and Ion Research (FAIR) at GSI, Germany. In previous design studies, two high beam intensities, 70 and 100 mA, were used. Most recently, the design intensity has been changed to 45 mA, which is closer to the operational value. Taking advantage of the so-called New Four-Section Procedure, a new design, which is upgradable from 45 to 100 mA, has been developed for the FAIR proton RFQ. Besides the upgradability analyses, robustness studies of the new design to spatial displacements of the input beam and field errors are presented as well.

Motivation for proposed experimentation in the realm of accelerated E. M. systems: A preliminary design for an experiment

NASA Technical Reports Server (NTRS)

Post, E. J.

1970-01-01

An experiment, designed to determine the difference between fields-magnetic and electric-surrounding a uniformly moving charge as contrasted with the fields surrounding an accelerated charge, is presented. A thought experiment is presented to illustrate the process.

Accelerator Science: Proton vs. Electron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

Particle accelerators are one of the most powerful ways to study the fundamental laws that govern the universe. However, there are many design considerations that go into selecting and building a particular accelerator. In this video, Fermilab’s Dr. Don Lincoln explains the pros and cons of building an accelerator that collides pairs of protons to one that collides electrons.

Design considerations for the use of laser-plasma accelerators for advanced space radiation studies

NASA Astrophysics Data System (ADS)

Königstein, T.; Karger, O.; Pretzler, G.; Rosenzweig, J. B.; Hidding, B.; Hidding

2012-08-01

We present design considerations for the use of laser-plasma accelerators for mimicking space radiation and testing space-grade electronics. This novel application takes advantage of the inherent ability of laser-plasma accelerators to produce particle beams with exponential energy distribution, which is a characteristic shared with the hazardous relativistic electron flux present in the radiation belts of planets such as Earth, Saturn and Jupiter. Fundamental issues regarding laser-plasma interaction parameters, beam propagation, flux development, and experimental setup are discussed.

Verification of mechanistic-empirical design models for flexible pavements through accelerated pavement testing : technical summary.

DOT National Transportation Integrated Search

2014-08-01

Midwest States Accelerated Pavement Testing Pooled-Fund Program, financed by the : highway departments of Kansas, Iowa, and Missouri, has supported an accelerated : pavement testing (APT) project to validate several models incorporated in the NCHRP :...

Accelerated testing for studying pavement design and performance (FY 2002) : research summary.

DOT National Transportation Integrated Search

2004-01-01

This report covers the Fiscal Year 2002 project conducted at the Accelerated Testing : Laboratory at Kansas State University. The project was selected and funded by the : Midwest States Accelerated Testing Pooled Fund Program, which includes Iowa, Ka...

Verification of mechanistic-empirical design models for flexible pavements through accelerated pavement testing.

DOT National Transportation Integrated Search

2014-08-01

The Midwest States Accelerated Pavement Testing Pooled Fund Program, financed by the highway : departments of Kansas, Iowa, and Missouri, has supported an accelerated pavement testing (APT) project to : validate several models incorporated in the NCH...

CEPC-SPPC accelerator status towards CDR

NASA Astrophysics Data System (ADS)

Gao, J.

2017-12-01

In this paper we will give an introduction to the Circular Electron Positron Collider (CEPC). The scientific background, physics goal, the collider design requirements and the conceptual design principle of the CEPC are described. On the CEPC accelerator, the optimization of parameter designs for the CEPC with different energies, machine lengths, single ring and crab-waist collision partial double ring, advanced partial double ring and fully partial double ring options, etc. have been discussed systematically, and compared. The CEPC accelerator baseline and alternative designs have been proposed based on the luminosity potential in relation with the design goals. The CEPC sub-systems, such as the collider main ring, booster, electron positron injector, etc. have also been introduced. The detector and the MAchine-Detector Interface (MDI) design have been briefly mentioned. Finally, the optimization design of the Super Proton-Proton Collider (SppC), its energy and luminosity potentials, in the same tunnel of the CEPC are also discussed. The CEPC-SppC Progress Report (2015-2016) has been published.

High gradient RF test results of S-band and C-band cavities for medical linear accelerators

DOE PAGES

Degiovanni, A.; Bonomi, R.; Garlasche, M.; ...

2018-02-09

TERA Foundation has proposed and designed hadrontherapy facilities based on novel linacs, i.e. high gradient linacs which accelerate either protons or light ions. The overall length of the linac, and therefore its cost, is almost inversely proportional to the average accelerating gradient. With the scope of studying the limiting factors for high gradient operation and to optimize the linac design, TERA, in collaboration with the CLIC Structure Development Group, has conducted a series of high gradient experiments. The main goals were to study the high gradient behavior and to evaluate the maximum gradient reached in 3 and 5.7 GHz structuresmore » to direct the design of medical accelerators based on high gradient linacs. Lastly, this paper summarizes the results of the high power tests of 3.0 and 5.7 GHz single-cell cavities.« less

SABRE, a 10-MV linear induction accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corely, J.P.; Alexander, J.A.; Pankuch, P.J.

SABRE (Sandia Accelerator and Beam Research Experiment) is a 10-MV, 250-kA, 40-ns linear induction accelerator. It was designed to be used in positive polarity output. Positive polarity accelerators are important for application to Sandia's ICF (Inertial Confinement Fusion) and LMF (Laboratory Microfusion Facility) program efforts. SABRE was built to allow a more detailed study of pulsed power issues associated with positive polarity output machines. MITL (Magnetically Insulated Transmission Line) voltage adder efficiency, extraction ion diode development, and ion beam transport and focusing. The SABRE design allows the system to operate in either positive polarity output for ion extraction applications ormore » negative polarity output for more conventional electron beam loads. Details of the design of SABRE and the results of initial machine performance in negative polarity operation are presented in this paper. 13 refs., 12 figs., 1 tab.« less

High gradient RF test results of S-band and C-band cavities for medical linear accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Degiovanni, A.; Bonomi, R.; Garlasche, M.

TERA Foundation has proposed and designed hadrontherapy facilities based on novel linacs, i.e. high gradient linacs which accelerate either protons or light ions. The overall length of the linac, and therefore its cost, is almost inversely proportional to the average accelerating gradient. With the scope of studying the limiting factors for high gradient operation and to optimize the linac design, TERA, in collaboration with the CLIC Structure Development Group, has conducted a series of high gradient experiments. The main goals were to study the high gradient behavior and to evaluate the maximum gradient reached in 3 and 5.7 GHz structuresmore » to direct the design of medical accelerators based on high gradient linacs. Lastly, this paper summarizes the results of the high power tests of 3.0 and 5.7 GHz single-cell cavities.« less

A button - type beam position monitor design for TARLA facility

NASA Astrophysics Data System (ADS)

Gündoǧan, M. Tural; Kaya, ć.; Yavaş, Ö.

2016-03-01

Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC). TARLA is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The TARLA facility is expected to provide two modes, Continuous wave (CW) and pulsed mode. Longitudinal electron bunch length will be changed between 1 and 10 ps. The bunch charge will be limited by 77pC. The design of the Button-type Beam Position Monitor for TARLA IR FEL is studied to operate in 1.3 GHz. Mechanical antenna design and simulations are completed considering electron beam parameters of TARLA. Ansoft HFSS and CST Particle Studio is used to compare with results of simulations.

Electric rail gun projectile acceleration to high velocity

NASA Technical Reports Server (NTRS)

Bauer, D. P.; Mccormick, T. J.; Barber, J. P.

1982-01-01

Electric rail accelerators are being investigated for application in electric propulsion systems. Several electric propulsion applications require that the rail accelerator be capable of launching projectiles at velocities above 10 km/s. An experimental program was conducted to develop rail accelerator technology for high velocity projectile launch. Several 6 mm bore, 3 m long rail accelerators were fabricated. Projectiles with a mass of 0.2 g were accelerated by plasmas, carrying currents up to 150 kA. Experimental design and results are described. Results indicate that the accelerator performed as predicted for a fraction of the total projectile acceleration. The disparity between predicted and measured results are discussed.

805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. Bricker; C. Compton; W. Hartung

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.more » 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.« less

New self-magnetically insulated connection of multilevel accelerators to a common load

DOE PAGES

VanDevender, J. Pace; Langston, William L.; Pasik, Michael F.; ...

2015-03-04

A new way to connect pulsed-power modules to a common load is presented. Unlike previous connectors, the clam shell magnetically insulated transmission line (CSMITL) has magnetic nulls only at large radius where the cathode electric field is kept below the threshold for emission, has only a simply connected magnetic topology to avoid plasma motion along magnetic field lines into highly stressed gaps, and has electron injectors that ensure efficient electron flow even in the limiting case of self-limited MITLs. Multilevel magnetically insulated transmission lines with a posthole convolute are the standard solution but associated losses limit the performance of state-of-the-artmore » accelerators. Mitigating these losses is critical for the next generation of pulsed-power accelerators. A CSMITL has been successfully implemented on the Saturn accelerator. A reference design for the Z accelerator is derived and presented. The design conservatively meets the design requirements and shows excellent transport efficiency in three simulations of increasing complexity: circuit simulations, electromagnetic fields only with Emphasis, fields plus electron and ion emission with Quicksilver.« less

Conceptual design of a high real-estate gradient cavity for a SRF ERL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Chen; Ben-Zvi, Ilan; Hao, Yue

The term “real-estate gradient” is used to describe the energy gain provided by an accelerating structure per actual length it takes in the accelerator. given that the length of the tunnel available for the accelerator is constrained, the real-estate gradient is an important measure of the efficiency of a given accelerator structure. When designing an accelerating cavity to be efficient in this sense, the unwanted Higher Order Mode (HOM) fields should be reduced by suitable HOM dampers. This is a particularly important consideration for high current operation. The additional RF components might take longitude space and reduce the total acceleratingmore » efficiency. We describe a new high efficiency 5-cell cavity with the dampers included. The total length of the cavity is reduced by 13% as compared to a more conventional design without compromising the cavity fundamental-mode performance. In addition, the HOM impedance is reduced for a higher Beam-Break-Up (BBU) threshold of operating current. In this article, we consider an example, a possible application at the eRHIC Energy Recovery Linac (ERL).« less

Conceptual design of a high real-estate gradient cavity for a SRF ERL

DOE PAGES

Xu, Chen; Ben-Zvi, Ilan; Hao, Yue; ...

2017-07-19

The term “real-estate gradient” is used to describe the energy gain provided by an accelerating structure per actual length it takes in the accelerator. given that the length of the tunnel available for the accelerator is constrained, the real-estate gradient is an important measure of the efficiency of a given accelerator structure. When designing an accelerating cavity to be efficient in this sense, the unwanted Higher Order Mode (HOM) fields should be reduced by suitable HOM dampers. This is a particularly important consideration for high current operation. The additional RF components might take longitude space and reduce the total acceleratingmore » efficiency. We describe a new high efficiency 5-cell cavity with the dampers included. The total length of the cavity is reduced by 13% as compared to a more conventional design without compromising the cavity fundamental-mode performance. In addition, the HOM impedance is reduced for a higher Beam-Break-Up (BBU) threshold of operating current. In this article, we consider an example, a possible application at the eRHIC Energy Recovery Linac (ERL).« less

Twin-Screw Extruder and Pellet Accelerator Integration Developments for ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meitner, Steven J; Baylor, Larry R; Combs, Stephen Kirk

The ITER pellet injection system consisting of a twinscrew frozen hydrogen isotope extruder, coupled to a combination solenoid actuated pellet cutter and pneumatic pellet accelerator, is under development at the Oak Ridge National Laboratory. A prototype extruder has been built to produce a continuous solid deuterium extrusion and will be integrated with a secondary section, where pellets are cut, chambered, and launched with a single-stage pneumatic accelerator into the plasma through a guide tube. This integrated pellet injection system is designed to provide 5 mm fueling pellets, injected at a rate up to 10 Hz, or 3 mm edge localizedmore » mode (ELM) triggering pellets, injected at higher rates up to 20 Hz. The pellet cutter, chamber mechanism, and the solenoid operated pneumatic valve for the accelerator are optimized to provide pellet velocities between 200-300 m/s to ensure high pellet survivability while traversing the inner wall fueling guide tubes, and outer wall ELMpacing guide tubes. This paper outlines the current twin-screwextruder design, pellet accelerator design, and the integrationrequired for both fueling and ELM pacing pellets.« less

Universality of accelerating change

NASA Astrophysics Data System (ADS)

Eliazar, Iddo; Shlesinger, Michael F.

2018-03-01

On large time scales the progress of human technology follows an exponential growth trend that is termed accelerating change. The exponential growth trend is commonly considered to be the amalgamated effect of consecutive technology revolutions - where the progress carried in by each technology revolution follows an S-curve, and where the aging of each technology revolution drives humanity to push for the next technology revolution. Thus, as a collective, mankind is the 'intelligent designer' of accelerating change. In this paper we establish that the exponential growth trend - and only this trend - emerges universally, on large time scales, from systems that combine together two elements: randomness and amalgamation. Hence, the universal generation of accelerating change can be attained by systems with no 'intelligent designer'.

Feasibility study of a cyclotron complex for hadron therapy

NASA Astrophysics Data System (ADS)

Smirnov, V.; Vorozhtsov, S.

2018-04-01

An accelerator complex for hadron therapy based on a chain of cyclotrons is under development at JINR (Dubna, Russia), and the corresponding conceptual design is under preparation. The complex mainly consists of two superconducting cyclotrons. The first accelerator is a compact cyclotron used as an injector to the main accelerator, which is a six-fold separated sector machine. The facility is intended for generation of protons and carbon beams. The H2+ and 12C6+ ions from the corresponding ECR ion sources are accelerated in the injector-cyclotron up to the output energy of 70 MeV/u. Then, the H2+ ions are extracted from the injector by a stripping foil, and the resulting proton beam with the energy of 70 MeV is used for medical purposes. After acceleration in the main cyclotron, the carbon beam can be either used directly for therapy or introduced to the main cyclotron for obtaining the final energy of 400 MeV/u. The basic requirements to the project are the following: compliance to medical requirements, compact size, feasible design, and high reliability of all systems of the complex. The advantages of the dual cyclotron design can help reaching these goals. The initial calculations show that this design is technically feasible with acceptable beam dynamics. The accelerator complex with a relatively compact size can be a good solution for medical applications. The basic parameters of the facility and detailed investigation of the magnetic system and beam dynamics are described.

Design, modeling and simulations of a Cabinet Safe System for a linear particle accelerator of intermediate-low energy by optimization of the beam optics

NASA Astrophysics Data System (ADS)

Maidana, Carlos Omar

As part of an accelerator based Cargo Inspection System, studies were made to develop a Cabinet Safe System by Optimization of the Beam Optics of Microwave Linear Accelerators of the IAC-Varian series working on the S-band and standing wave pi/2 mode. Measurements, modeling and simulations of the main subsystems were done and a Multiple Solenoidal System was designed. This Cabinet Safe System based on a Multiple Solenoidal System minimizes the radiation field generated by the low efficiency of the microwave accelerators by optimizing the RF waveguide system and by also trapping secondaries generated in the accelerator head. These secondaries are generated mainly due to instabilities in the exit window region and particles backscattered from the target. The electron gun was also studied and software for its right mechanical design and for its optimization was developed as well. Besides the standard design method, an optimization of the injection process is accomplished by slightly modifying the gun configuration and by placing a solenoid on the waist position while avoiding threading the cathode with the magnetic flux generated. The Multiple Solenoidal System and the electron gun optimization are the backbone of a Cabinet Safe System that could be applied not only to the 25 MeV IAC-Varian microwave accelerators but, by extension, to machines of different manufacturers as well. Thus, they constitute the main topic of this dissertation.

Accelerator Science: Proton vs. Electron

ScienceCinema

Lincoln, Don

2018-06-12

Particle accelerators are one of the most powerful ways to study the fundamental laws that govern the universe. However, there are many design considerations that go into selecting and building a particular accelerator. In this video, Fermilab’s Dr. Don Lincoln explains the pros and cons of building an accelerator that collides pairs of protons to one that collides electrons.

Design and analysis of fractional order seismic transducer for displacement and acceleration measurements

NASA Astrophysics Data System (ADS)

Veeraian, Parthasarathi; Gandhi, Uma; Mangalanathan, Umapathy

2018-04-01

Seismic transducers are widely used for measurement of displacement, velocity, and acceleration. This paper presents the design of seismic transducer in the fractional domain for the measurement of displacement and acceleration. The fractional order transfer function for seismic displacement and acceleration transducer are derived using Grünwald-Letnikov derivative. Frequency response analysis of fractional order seismic displacement transducer (FOSDT) and fractional order seismic acceleration transducer (FOSAT) are carried out for different damping ratio with the different fractional order, and the maximum dynamic measurement range is identified. The results demonstrate that fractional order seismic transducer has increased dynamic measurement range and less phase distortion as compared to the conventional seismic transducer even with a lower damping ratio. Time response of FOSDT and FOSAT are derived analytically in terms of Mittag-Leffler function, the effect of fractional behavior in the time domain is evaluated from the impulse and step response. The fractional order system is found to have significantly reduced overshoot as compared to the conventional transducer. The fractional order seismic transducer design proposed in this paper is illustrated with a design example for FOSDT and FOSAT. Finally, an electrical equivalent of FOSDT and FOSAT is considered, and its frequency response is found to be in close agreement with the proposed fractional order seismic transducer.

An introduction to the physics of high energy accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1993-01-01

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

Prototyping high-gradient mm-wave accelerating structures

DOE PAGES

Nanni, Emilio A.; Dolgashev, Valery A.; Haase, Andrew; ...

2017-01-01

We present single-cell accelerating structures designed for high-gradient testing at 110 GHz. The purpose of this work is to study the basic physics of ultrahigh vacuum RF breakdown in high-gradient RF accelerators. The accelerating structures are π-mode standing-wave cavities fed with a TM 01 circular waveguide. The structures are fabricated using precision milling out of two metal blocks, and the blocks are joined with diffusion bonding and brazing. The impact of fabrication and joining techniques on the cell geometry and RF performance will be discussed. First prototypes had a measured Q 0 of 2800, approaching the theoretical design value ofmore » 3300. The geometry of these accelerating structures are as close as practical to singlecell standing-wave X-band accelerating structures more than 40 of which were tested at SLAC. This wealth of X-band data will serve as a baseline for these 110 GHz tests. Furthermore, the structures will be powered with short pulses from a MW gyrotron oscillator. RF power of 1 MW may allow an accelerating gradient of 400 MeV/m to be reached.« less

Electromagnetic launchers for space applications

NASA Technical Reports Server (NTRS)

Schroeder, J. M.; Gully, J. H.; Driga, M. D.

1989-01-01

An electromagnetic launcher (EML) was designed for NASA-Langley to boost large models to hypervelocity for flight evaluation. Two different concepts were developed using railgun and coilgun principles. A coilgun was designed to accelerate a 14-kg mass to 6 km/s and, by adding additional equipment, to accelerate a 10-kg mass to 11 km/s. The railgun system was designed to accelerate only 14 kg to 6 km/s. Of significance in this development is the opportunity to use the launcher for aeroballistic research of the upper atmosphere, eventually placing packages in low earth orbit using a small rocket. The authors describe the railgun and coilgun launch designs and suggest a reconfiguration for placement of 150-kg parcels into low earth orbit for aeroballistic studies and possible space lab support. Each design is detailed along with the performance adjustments which would be required for circular orbit payload placement.

Exceedance statistics of accelerations resulting from thruster firings on the Apollo-Soyuz mission

NASA Technical Reports Server (NTRS)

Fichtl, G. H.; Holland, R. L.

1981-01-01

Spacecraft acceleration resulting from firings of vernier control system thrusters is an important consideration in the design, planning, execution and post-flight analysis of laboratory experiments in space. In particular, scientists and technologists involved with the development of experiments to be performed in space in many instances required statistical information on the magnitude and rate of occurrence of spacecraft accelerations. Typically, these accelerations are stochastic in nature, so that it is useful to characterize these accelerations in statistical terms. Statistics of spacecraft accelerations are summarized.

Isochronous (CW) Non-Scaling FFAGs: Design and Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnstone, C.; Berz, M.; Makino, K.

2010-11-04

The drive for higher beam power, high duty cycle, and reliable beams at reasonable cost has focused international attention and design effort on fixed field accelerators, notably Fixed-Field Alternating Gradient accelerators (FFAGs). High-intensity GeV proton drivers encounter duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons. A 10-20 MW proton driver is challenging, if even technically feasible, with conventional accelerators--with the possible exception of a SRF linac, which has a large associated cost and footprint. Recently, the concept of isochronous orbits has been explored and developed for nonscaling FFAGs using powerful new methodologiesmore » in FFAG accelerator design and simulation. The property of isochronous orbits enables the simplicity of fixed RF and, by tailoring a nonlinear radial field profile, the FFAG can remain isochronous beyond the energy reach of cyclotrons, well into the relativistic regime. With isochronous orbits, the machine proposed here has the high average current advantage and duty cycle of the cyclotron in combination with the strong focusing, smaller losses, and energy variability that are more typical of the synchrotron. This paper reports on these new advances in FFAG accelerator technology and presents advanced modeling tools for fixed-field accelerators unique to the code COSY INFINITY.« less

Lattice design and beam dynamics studies of the high energy beam transport line in the RAON heavy ion accelerator

NASA Astrophysics Data System (ADS)

Jin, Hyunchang; Jang, Ji-Ho; Jang, Hyojae; Jeon, Dong-O.

2015-12-01

In RAON heavy ion accelerator, beams generated by superconducting electron cyclotron resonance ion source (ECR-IS) or Isotope Separation On-Line (ISOL) system are accelerated by lower energy superconducting linac and high energy superconducting linac. The accelerated beams are used in the high energy experimental hall which includes bio-medical and muon-SR facilities, after passing through the high energy beam transport lines. At the targets of those two facilities, the stable and small beams meeting the requirements rigorously are required in the transverse plane. Therefore the beams must be safely sent to the targets and simultaneously satisfy the two requirements, the achromatic condition and the mid-plane symmetric condition, of the targets. For this reason, the lattice design of the high energy beam transport lines in which the long deflecting sections are included is considered as a significant issue in the RAON accelerator. In this paper, we will describe the calculated beam optics satisfying the conditions and present the result of particle tracking simulations with the designed lattice of the high energy beam transport lines in the RAON accelerator. Also, the orbit distortion caused by the machine imperfections and the orbit correction with correctors will be discussed.

Beam dynamics simulations of post low energy beam transport section in RAON heavy ion accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Hyunchang, E-mail: hcjin@ibs.re.kr; Jang, Ji-Ho; Jang, Hyojae

RAON (Rare isotope Accelerator Of Newness) heavy ion accelerator of the rare isotope science project in Daejeon, Korea, has been designed to accelerate multiple-charge-state beams to be used for various science programs. In the RAON accelerator, the rare isotope beams which are generated by an isotope separation on-line system with a wide range of nuclei and charges will be transported through the post Low Energy Beam Transport (LEBT) section to the Radio Frequency Quadrupole (RFQ). In order to transport many kinds of rare isotope beams stably to the RFQ, the post LEBT should be devised to satisfy the requirement ofmore » the RFQ at the end of post LEBT, simultaneously with the twiss parameters small. We will present the recent lattice design of the post LEBT in the RAON accelerator and the results of the beam dynamics simulations from it. In addition, the error analysis and correction in the post LEBT will be also described.« less

Wireless acceleration sensor of moving elements for condition monitoring of mechanisms

NASA Astrophysics Data System (ADS)

Sinitsin, Vladimir V.; Shestakov, Aleksandr L.

2017-09-01

Comprehensive analysis of the angular and linear accelerations of moving elements (shafts, gears) allows an increase in the quality of the condition monitoring of mechanisms. However, existing tools and methods measure either linear or angular acceleration with postprocessing. This paper suggests a new construction design of an angular acceleration sensor for moving elements. The sensor is mounted on a moving element and, among other things, the data transfer and electric power supply are carried out wirelessly. In addition, the authors introduce a method for processing the received information which makes it possible to divide the measured acceleration into the angular and linear components. The design has been validated by the results of laboratory tests of an experimental model of the sensor. The study has shown that this method provides a definite separation of the measured acceleration into linear and angular components, even in noise. This research contributes an advance in the range of methods and tools for condition monitoring of mechanisms.

Compact and tunable focusing device for plasma wakefield acceleration

NASA Astrophysics Data System (ADS)

Pompili, R.; Anania, M. P.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Lollo, V.; Notargiacomo, A.; Picardi, L.; Ronsivalle, C.; Rosenzweig, J. B.; Shpakov, V.; Vannozzi, A.

2018-03-01

Plasma wakefield acceleration, either driven by ultra-short laser pulses or electron bunches, represents one of the most promising techniques able to overcome the limits of conventional RF technology and allows the development of compact accelerators. In the particle beam-driven scenario, ultra-short bunches with tiny spot sizes are required to enhance the accelerating gradient and preserve the emittance and energy spread of the accelerated bunch. To achieve such tight transverse beam sizes, a focusing system with short focal length is mandatory. Here we discuss the development of a compact and tunable system consisting of three small-bore permanent-magnet quadrupoles with 520 T/m field gradient. The device has been designed in view of the plasma acceleration experiments planned at the SPARC_LAB test-facility. Being the field gradient fixed, the focusing is adjusted by tuning the relative position of the three magnets with nanometer resolution. Details about its magnetic design, beam-dynamics simulations, and preliminary results are examined in the paper.

Hubble peeks at a spiral galaxy

NASA Image and Video Library

2015-07-10

This little-known galaxy, officially named J04542829-6625280, but most often referred to as LEDA 89996, is a classic example of a spiral galaxy. The galaxy is much like our own galaxy, the Milky Way. The disk-shaped galaxy is seen face on, revealing the winding structure of the spiral arms. Dark patches in these spiral arms are in fact dust and gas — the raw materials for new stars. The many young stars that form in these regions make the spiral arms appear bright and bluish. The galaxy sits in a vibrant area of the night sky within the constellation of Dorado (The Swordfish), and appears very close to the Large Magellanic Cloud — one of the satellite galaxies of the Milky Way. The observations were carried out with the high resolution channel of Hubble’s Advanced Camera for Surveys. Image credit: ESA/Hubble & NASA, Acknowledgement: Flickr user C. Claude NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Galaxy with a view

NASA Image and Video Library

2015-07-06

This little-known galaxy, officially named J04542829-6625280, but most often referred to as LEDA 89996, is a classic example of a spiral galaxy. The galaxy is much like our own galaxy, the Milky Way. The disc-shaped galaxy is seen face on, revealing the winding structure of the spiral arms. Dark patches in these spiral arms are in fact dust and gas — the raw materials for new stars. The many young stars that form in these regions make the spiral arms appear bright and bluish. The galaxy sits in a vibrant area of the night sky within the constellation of Dorado (The Swordfish), and appears very close to the Large Magellanic Cloud  — one of the satellite galaxies of the Milky Way. The observations were carried out with the high resolution channel of Hubble’s Advanced Camera for Surveys. This instrument has delivered some of the sharpest views of the Universe so far achieved by mankind. This image covers only a tiny patch of sky — about the size of a one cent euro coin held 100 metres away! A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by flickr user c.claude.

Hardware accelerated high performance neutron transport computation based on AGENT methodology

NASA Astrophysics Data System (ADS)

Xiao, Shanjie

The spatial heterogeneity of the next generation Gen-IV nuclear reactor core designs brings challenges to the neutron transport analysis. The Arbitrary Geometry Neutron Transport (AGENT) AGENT code is a three-dimensional neutron transport analysis code being developed at the Laboratory for Neutronics and Geometry Computation (NEGE) at Purdue University. It can accurately describe the spatial heterogeneity in a hierarchical structure through the R-function solid modeler. The previous version of AGENT coupled the 2D transport MOC solver and the 1D diffusion NEM solver to solve the three dimensional Boltzmann transport equation. In this research, the 2D/1D coupling methodology was expanded to couple two transport solvers, the radial 2D MOC solver and the axial 1D MOC solver, for better accuracy. The expansion was benchmarked with the widely applied C5G7 benchmark models and two fast breeder reactor models, and showed good agreement with the reference Monte Carlo results. In practice, the accurate neutron transport analysis for a full reactor core is still time-consuming and thus limits its application. Therefore, another content of my research is focused on designing a specific hardware based on the reconfigurable computing technique in order to accelerate AGENT computations. It is the first time that the application of this type is used to the reactor physics and neutron transport for reactor design. The most time consuming part of the AGENT algorithm was identified. Moreover, the architecture of the AGENT acceleration system was designed based on the analysis. Through the parallel computation on the specially designed, highly efficient architecture, the acceleration design on FPGA acquires high performance at the much lower working frequency than CPUs. The whole design simulations show that the acceleration design would be able to speedup large scale AGENT computations about 20 times. The high performance AGENT acceleration system will drastically shortening the computation time for 3D full-core neutron transport analysis, making the AGENT methodology unique and advantageous, and thus supplies the possibility to extend the application range of neutron transport analysis in either industry engineering or academic research.

Design Challenges of a Rapid Cycling Synchrotron for Carbon/Proton Therapy

NASA Astrophysics Data System (ADS)

Cook, Nathan

2012-03-01

The growing interest in radiation therapy with protons and light ions has driven demand for new methods of ion acceleration and the delivery of ion beams. One exciting new platform for ion beam acceleration and delivery is the rapid cycling synchrotron. Operating at 15Hz, rapid cycling achieves faster treatment times by making beam extraction possible at any energy during the cycle. Moreover, risk to the patient is reduced by requiring fewer particles in the beam line at a given time, thus eliminating the need for passive filtering and reducing the consequences of a malfunction. Lastly, the ability to switch between carbon ion and proton beam therapy provides the machine with an unmatched flexibility. However, these features do stipulate challenges in accelerator design. Maintaining a compact lattice requires careful tuning of lattice functions, tight focusing combined function magnets, and fast injection and extraction systems. Providing the necessary acceleration over a short cycle time also necessitates a five-fold frequency swing for carbon ions, further burdening the design requirements of ferrite-driven radiofrequency cavities. We will consider these challenges as well as some solutions selected for our current design.

Symposium on Electromagnetic Launcher Technology, 5th, Sandestin, FL, Apr. 3-5, 1990, Proceedings

NASA Astrophysics Data System (ADS)

Gooden, Clarence E.

1991-01-01

The present conference on electromagnetic accelerators (EMAs) and railguns (RGs) discusses active-current management for four-rail RGs, the design of a compulsator-drive 60-caliber RG, EMA studies with augmented rails, muzzle-shunt augmentation of conventional RGs, effect of in-bore gas on RG performance, the distributed-energy store RG, plasma diagnostics for high power ignitron development, a review of EMA armature research, RG hybrid armatures, a new solid-armature design concept, and the electrodynamics of RG plasma armatures. Also discussed is RG modeling at speed using three-dimensional finite elements, power supply technology for EMAs, rotating machine power supplies for next-generation EMAs, advanced EMA power supplies with magnetic-flux compression, metal-to-metal switches for large currents, lightweight high-effiency energy-storage transformers, hypervelocity projectile development for EMAs, structural design issues for EMA projectiles, stiff RGs, a reinforced Al conductor for cryogenic applications, mass-stabilized projectile designs for EMA launch, indictively-commutated coilguns, an actively switched pulsed induction accelerator, a plasma gun-augmented electrothermal accelerator, a symmetrical rail accelerator, and a travelling-wave synchronous coil gun.

NWSC nickel cadmium spacecraft cell accelerated life test program data analysis

NASA Technical Reports Server (NTRS)

Lander, J.

1980-01-01

An analysis of the data leading to a proposed accelerated life test scheme to test a nickel cadmium cell under spacecraft usage conditions is described. The amount and concentration of electrolyte and the amount of precharge in the cell are discussed in relation to the design of the cell and the accelerated test design. A failure analysis of the cell is summarized. The analysis included such environmental test variables as the depth of discharge, the temperature, the amount of recharge and the charge and discharge rate.

Experimental evaluation of the Battelle accelerated test design for the solar array at Mead, Nebraska

NASA Technical Reports Server (NTRS)

Frickland, P. O.; Repar, J.

1982-01-01

A previously developed test design for accelerated aging of photovoltaic modules was experimentally evaluated. The studies included a review of relevant field experience, environmental chamber cycling of full size modules, and electrical and physical evaluation of the effects of accelerated aging during and after the tests. The test results indicated that thermally induced fatigue of the interconnects was the primary mode of module failure as measured by normalized power output. No chemical change in the silicone encapsulant was detectable after 360 test cycles.

PARTICLE ACCELERATOR AND METHOD OF CONTROLLING THE TEMPERATURE THEREOF

DOEpatents

Neal, R.B.; Gallagher, W.J.

1960-10-11

A method and means for controlling the temperature of a particle accelerator and more particularly to the maintenance of a constant and uniform temperature throughout a particle accelerator is offered. The novel feature of the invention resides in the provision of two individual heating applications to the accelerator structure. The first heating application provided is substantially a duplication of the accelerator heat created from energization, this first application being employed only when the accelerator is de-energized thereby maintaining the accelerator temperature constant with regard to time whether the accelerator is energized or not. The second heating application provided is designed to add to either the first application or energization heat in a manner to create the same uniform temperature throughout all portions of the accelerator.

Accelerated testing for studying pavement design and performance (FY 2003) : evaluation of the chemical stabilized subgrade soil (CISL Experiment No. 12).

DOT National Transportation Integrated Search

2008-01-01

The Midwest States Accelerated Pavement Testing Pooled Fund Program, financed by the highway departments : of Missouri, Iowa, Kansas and Nebraska, has supported an accelerated pavement testing (APT) project to compare : the performance of stabilized ...

Design and Analysis of Megawatt Class Free Electron Laser Weapons

DTIC Science & Technology

2015-12-01

accelerating structure. The SRF linear accelerator stores RF fields within its niobium cavities. Superconductors require less average RF power than...is needed to cool the superconductor for the SRF linear accelerator. A current outstanding research topic is the RF frequency to use for the SRF

Adaptation to vestibular disorientation. XI, The influence of specific and nonspecific gravi-receptors on nystagmic responses to angular acceleration.

DOT National Transportation Integrated Search

1969-10-01

Data from several recent experiments indicate that the otoliths (detectors of linear acceleration) may exert regulatory effects on responses of the semicircular canals (detectors of angular acceleration). This study was designed to explore further th...

Accelerators as Authentic Training Experiences for Nascent Entrepreneurs

ERIC Educational Resources Information Center

Miles, Morgan P.; de Vries, Huibert; Harrison, Geoff; Bliemel, Martin; de Klerk, Saskia; Kasouf, Chick J.

2017-01-01

Purpose: The purpose of this paper is to address the role of accelerators as authentic learning-based entrepreneurial training programs. Accelerators facilitate the development and assessment of entrepreneurial competencies in nascent entrepreneurs through the process of creating a start-up venture. Design/methodology/approach: Survey data from…

Industrialization of Superconducting RF Accelerator Technology

NASA Astrophysics Data System (ADS)

Peiniger, Michael; Pekeler, Michael; Vogel, Hanspeter

2012-01-01

Superconducting RF (SRF) accelerator technology has basically existed for 50 years. It took about 20 years to conduct basic R&D and prototyping at universities and international institutes before the first superconducting accelerators were built, with industry supplying complete accelerator cavities. In parallel, the design of large scale accelerators using SRF was done worldwide. In order to build those accelerators, industry has been involved for 30 years in building the required cavities and/or accelerator modules in time and budget. To enable industry to supply these high tech components, technology transfer was made from the laboratories in the following three regions: the Americas, Asia and Europe. As will be shown, the manufacture of the SRF cavities is normally accomplished in industry whereas the cavity testing and module assembly are not performed in industry in most cases, yet. The story of industrialization is so far a story of customized projects. Therefore a real SRF accelerator product is not yet available in this market. License agreements and technology transfer between leading SRF laboratories and industry is a powerful tool for enabling industry to manufacture SRF components or turnkey superconducting accelerator modules for other laboratories and users with few or no capabilities in SRF technology. Despite all this, the SRF accelerator market today is still a small market. The manufacture and preparation of the components require a range of specialized knowledge, as well as complex and expensive manufacturing installations like for high precision machining, electron beam welding, chemical surface preparation and class ISO4 clean room assembly. Today, the involved industry in the US and Europe comprises medium-sized companies. In Japan, some big enterprises are involved. So far, roughly 2500 SRF cavities have been built by or ordered from industry worldwide. Another substantial step might come from the International Linear Collider (ILC) project currently being designed by the international collaboration GDE (`global design effort'). If the ILC will be built, about 18,000 SRF cavities need to be manufactured worldwide within about five years. The industrialization of SRF accelerator technology is analyzed and reviewed in this article in view of the main accelerator projects of the last two to three decades.

Amplitude-dependent orbital period in alternating gradient accelerators

DOE PAGES

Machida, S.; Kelliher, D. J.; Edmonds, C. S.; ...

2016-03-16

Orbital period in a ring accelerator and time of flight in a linear accelerator depend on the amplitude of betatron oscillations. The variation is negligible in ordinary particle accelerators with relatively small beam emittance. In an accelerator for large emittance beams like muons and unstable nuclei, however, this effect cannot be ignored. In this study, we measured orbital period in a linear non-scaling fixed-field alternating-gradient accelerator, which is a candidate for muon acceleration, and compared it with the theoretical prediction. The good agreement between them gives important ground for the design of particle accelerators for a new generation of particlemore » and nuclear physics experiments.« less

Acceleration modules in linear induction accelerators

NASA Astrophysics Data System (ADS)

Wang, Shao-Heng; Deng, Jian-Jun

2014-05-01

The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

Possibility for ultra-bright electron beam acceleration in dielectric wakefield accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simakov, Evgenya I.; Carlsten, Bruce E.; Shchegolkov, Dmitry Yu.

2012-12-21

We describe a conceptual proposal to combine the Dielectric Wakefield Accelerator (DWA) with the Emittance Exchanger (EEX) to demonstrate a high-brightness DWA with a gradient of above 100 MV/m and less than 0.1% induced energy spread in the accelerated beam. We currently evaluate the DWA concept as a performance upgrade for the future LANL signature facility MaRIE with the goal of significantly reducing the electron beam energy spread. The preconceptual design for MaRIE is underway at LANL, with the design of the electron linear accelerator being one of the main research goals. Although generally the baseline design needs to bemore » conservative and rely on existing technology, any future upgrade would immediately call for looking into the advanced accelerator concepts capable of boosting the electron beam energy up by a few GeV in a very short distance without degrading the beam's quality. Scoping studies have identified large induced energy spreads as the major cause of beam quality degradation in high-gradient advanced accelerators for free-electron lasers. We describe simulations demonstrating that trapezoidal bunch shapes can be used in a DWA to greatly reduce the induced beam energy spread, and, in doing so, also preserve the beam brightness at levels never previously achieved. This concept has the potential to advance DWA technology to a level that would make it suitable for the upgrades of the proposed Los Alamos MaRIE signature facility.« less

High efficiency ion beam accelerator system

NASA Technical Reports Server (NTRS)

Aston, G.

1981-01-01

An ion accelerator system that successfully combines geometrical and electrostatic focusing principles is presented. This accelerator system uses thin, concave, multiple-hole, closely spaced graphite screen and focusing grids which are coupled to single slot accelerator and decelerator grids to provide high ion extraction efficiency and good focusing. Tests with the system showed a substantial improvement in ion beam current density and collimation as compared with a Pierce electrode configuration. Durability of the thin graphite screen and focusing grids has been proven, and tests are being performed to determine the minimum screen and focusing grid spacing and thickness required to extract the maximum reliable beam current density. Compared with present neutral beam injector accelerator systems, this one has more efficient ion extraction, easier grid alignment, easier fabrication, a less cumbersome design, and the capacity to be constructed in a modular fashion. Conceptual neutral beam injector designs using this modular approach have electrostatic beam deflection plates downstream of each module.

Slot-coupled CW standing wave accelerating cavity

DOEpatents

Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

2017-05-16

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

2012-05-08

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

Simon van der Meer (1925-2011):. A Modest Genius of Accelerator Science

NASA Astrophysics Data System (ADS)

Chohan, Vinod C.

2011-02-01

Simon van der Meer was a brilliant scientist and a true giant of accelerator science. His seminal contributions to accelerator science have been essential to this day in our quest for satisfying the demands of modern particle physics. Whether we talk of long base-line neutrino physics or antiproton-proton physics at Fermilab or proton-proton physics at LHC, his techniques and inventions have been a vital part of the modern day successes. Simon van der Meer and Carlo Rubbia were the first CERN scientists to become Nobel laureates in Physics, in 1984. Van der Meer's lesserknown contributions spanned a whole range of subjects in accelerator science, from magnet design to power supply design, beam measurements, slow beam extraction, sophisticated programs and controls.

Introduction to spallation physics and spallation-target design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, G.J.; Pitcher, E.J.; Daemen, L.L.

1995-10-01

When coupled with the spallation process in appropriate target materials, high-power accelerators can be used to produce large numbers of neutrons, thus providing an alternate method to the use of nuclear reactors for this purpose. Spallation offers exciting new possibilities for generating intense neutron fluxes for a variety of applications, including: (a) spallation-neutron sources for materials science research; (b) accelerator-based production of tritium; (c) accelerator-based transmutation of waste; (d) accelerator-based destruction of plutonium; and (e) radioisotope production for medical and energy applications. Target design plays a key role in these applications, with neutron production/leakage being strongly dependent on the incidentmore » particle type and energy, and target material and geometry.« less

Thomas Edison Accelerated Elementary School.

ERIC Educational Resources Information Center

Levin, Henry M.; Chasin, Gene

This paper describes early outcomes of a Sacramento, California, elementary school that participated in the Accelerated Schools Project. The school, which serves many minority and poor students, began training for the project in 1992. Accelerated Schools were designed to advance the learning rate of students through a gifted and talented approach,…

Accelerated Reader Program: What Do Teachers Really Think?

ERIC Educational Resources Information Center

Smith, Amy Frances; Westberg, Karen; Hejny, Anne

2017-01-01

What do teachers really think about the Accelerated Reader program, a widely used supplemental, independent reading program in which their students read fiction and non-fiction books of their choice and take brief online comprehension quizzes about the books? The Accelerated Reader (AR) program was designed by Renaissance Learning Company to…

Accelerated testing for studying pavement design and performance (FY 2002) : performance of foamed asphalt stabilized base in full depth reclaimed asphalt pavement.

DOT National Transportation Integrated Search

2004-08-01

This report covers the Fiscal Year 2002 project conducted at the Accelerated Testing Laboratory at Kansas : State University. The project was selected and funded by the Midwest Accelerated Testing Pooled Fund Program , : which includes Iowa, Kansas, ...

Lessons Learned from Accelerating Opportunity. Lessons Learned Series

ERIC Educational Resources Information Center

Wilson, Randall

2015-01-01

The Accelerating Opportunity initiative helps our nation's lowest-skilled adults earn college credentials and enter higher-wage jobs faster by combining the Adult Basic Education and career and technical training they need into one integrated curriculum. Based on four years of designing and managing Accelerating Opportunity, Jobs for the Future…

Exceedance statistics of accelerations resulting from thruster firings on the Apollo-Soyuz mission

NASA Technical Reports Server (NTRS)

Fichtl, G. H.; Holland, R. L.

1983-01-01

Spacecraft acceleration resulting from firings of vernier control system thrusters is an important consideration in the design, planning, execution and post-flight analysis of laboratory experiments in space. In particular, scientists and technologists involved with the development of experiments to be performed in space in many instances required statistical information on the magnitude and rate of occurrence of spacecraft accelerations. Typically, these accelerations are stochastic in nature, so that it is useful to characterize these accelerations in statistical terms. Statistics of spacecraft accelerations are summarized. Previously announced in STAR as N82-12127

High power neutron production targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wender, S.

1996-06-01

The author describes issues of concern in the design of targets and associated systems for high power neutron production facilities. The facilities include uses for neutron scattering, accelerator driven transmutation, accelerator production of tritium, short pulse spallation sources, and long pulse spallation sources. Each of these applications requires a source with different design needs and consequently different implementation in practise.

Design of general apochromatic drift-quadrupole beam lines

NASA Astrophysics Data System (ADS)

Lindstrøm, C. A.; Adli, E.

2016-07-01

Chromatic errors are normally corrected using sextupoles in regions of large dispersion. In low emittance linear accelerators, use of sextupoles can be challenging. Apochromatic focusing is a lesser-known alternative approach, whereby chromatic errors of Twiss parameters are corrected without the use of sextupoles, and has consequently been subject to renewed interest in advanced linear accelerator research. Proof of principle designs were first established by Montague and Ruggiero and developed more recently by Balandin et al. We describe a general method for designing drift-quadrupole beam lines of arbitrary order in apochromatic correction, including analytic expressions for emittance growth and other merit functions. Worked examples are shown for plasma wakefield accelerator staging optics and for a simple final focus system.

An algorithm for the design and tuning of RF accelerating structures with variable cell lengths

NASA Astrophysics Data System (ADS)

Lal, Shankar; Pant, K. K.

2018-05-01

An algorithm is proposed for the design of a π mode standing wave buncher structure with variable cell lengths. It employs a two-parameter, multi-step approach for the design of the structure with desired resonant frequency and field flatness. The algorithm, along with analytical scaling laws for the design of the RF power coupling slot, makes it possible to accurately design the structure employing a freely available electromagnetic code like SUPERFISH. To compensate for machining errors, a tuning method has been devised to achieve desired RF parameters for the structure, which has been qualified by the successful tuning of a 7-cell buncher to π mode frequency of 2856 MHz with field flatness <3% and RF coupling coefficient close to unity. The proposed design algorithm and tuning method have demonstrated the feasibility of developing an S-band accelerating structure for desired RF parameters with a relatively relaxed machining tolerance of ∼ 25 μm. This paper discusses the algorithm for the design and tuning of an RF accelerating structure with variable cell lengths.

OARE and SAMS on STS-94/MSL-1

NASA Technical Reports Server (NTRS)

Moskowitz, Milton; Hrovat, Kenneth; McPherson, Kevin; Tschen, Peter; DeLombard, Richard; Nati, Maurizio

1998-01-01

Four microgravity acceleration measurement instruments were included on MSL-1 to measure the accelerations and vibrations to which science experiments were exposed during their operation on the mission. The data were processed and presented to the principal investigators in a variety of formats to aid their assessment of the microgravity environment during their experiment operations. Two accelerometer systems managed by the NASA Lewis Research Center (LeRC) supported the MSL-1 mission: the Orbital Acceleration Research Experiment (OARE), and the Space Acceleration Measurement System (SAMS). In addition, the Microgravity Measurement Assembly (MMA) and the Quasi- Steady Acceleration Measurement (QSAM) system, both sponsored by the Microgravity Research Division, collected acceleration data as a part of the MSL-1 mission. The NIMA was funded and designed by the European Space Agency in the Netherlands (ESA/ESTEC), and the QSAM system was funded and designed by the German Space Agency (DLR). The Principal Investigator Microgravity Services (PIMS) project at the NASA Lewis Research Center (LeRC) supports Principal Investigators (PIs) of the Microgravity science community as they evaluate the effects of acceleration on their experiments. PIMS primary responsibility is to support NASA-sponsored investigators in the area of acceleration data analysis and interpretation. A mission summary report was prepared and published by PIMS in order to furnish interested experiment investigators with a guide for evaluating the acceleration environment during the MSL-1 mission.

An investigation into the effectiveness of smartphone experiments on students’ conceptual knowledge about acceleration

NASA Astrophysics Data System (ADS)

Mazzella, Alessandra; Testa, Italo

2016-09-01

This study is a first attempt to investigate effectiveness of smartphone-based activities on students’ conceptual understanding of acceleration. 143 secondary school students (15-16 years old) were involved in two types of activities: smartphone- and non-smartphone activities. The latter consisted in data logging and ‘cookbook’ activities. For the sake of comparison, all activities featured the same phenomena, i.e., the motion on an inclined plane and pendulum oscillations. A pre-post design was adopted, using open questionnaires as probes. Results show only weak statistical differences between the smartphone and non-smartphone groups. Students who followed smartphone activities were more able to design an experiment to measure acceleration and to correctly describe acceleration in a free fall motion. However, students of both groups had many difficulties in drawing acceleration vector along the trajectory of the studied motion. Results suggest that smartphone-based activities may be effective substitutes of traditional experimental settings and represent a valuable aid for teachers who want to implement laboratory activities at secondary school level. However, to achieve a deeper conceptual understanding of acceleration, some issues need to be addressed: what is the reference system of the built-in smartphone sensor; relationships between smartphone acceleration graphs and experimental setup; vector representation of the measured acceleration.

Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

NASA Astrophysics Data System (ADS)

Shope, S. L.; Mazarakis, M. G.; Frost, C. A.; Poukey, J. W.; Turman, B. N.

Self Magnetically Insulated Transmission Lines (MITL) adders were used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r(sub rho) less than 2 cm), 11 - 15 MeV, 50 - 100-kA beams with a small transverse velocity v(perpendicular)/c = beta(perpendicular) less than or equal to 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30 - 50 ns FWHM output pulse.

Muon Acceleration Concepts for NuMAX: "Dual-use" Linac and "Dogbone" RLA

DOE PAGES

Bogacz, S. A.

2018-02-01

In this paper, we summarize the current state of a concept for muon acceleration aimed at a future Neutrino Factory. The main thrust of these studies was to reduce the overall cost while maintaining performance by exploring the interplay between the complexity of the cooling systems and the acceptance of the accelerator complex. To ensure adequate survival for the short-lived muons, acceleration must occur at high average gradient. The need for large transverse and longitudinal acceptances drives the design of the acceleration system to an initially low RF frequency, e.g., 325 MHz, which is then increased to 650 MHz asmore » the transverse size shrinks with increasing energy. High-gradient normal conducting RF cavities at these frequencies require extremely high peak-power RF sources. Hence superconducting RF (SRF) cavities are chosen. Finally, we consider two cost effective schemes for accelerating muon beams for a stageable Neutrino Factory: exploration of the so-called "dual-use" linac concept, where the same linac structure is used for acceleration of both H - and muons and, alternatively, an SRF-efficient design based on a multi-pass (4.5) "dogbone" RLA, extendable to multi-pass FFAG-like arcs.« less

Design of a New Acceleration System for High-Current Pulsed Proton Beams from an ECR Source

NASA Astrophysics Data System (ADS)

Cooper, Andrew L.; Pogrebnyak, Ivan; Surbrook, Jason T.; Kelly, Keegan J.; Carlin, Bret P.; Champagne, Arthur E.; Clegg, Thomas B.

2014-03-01

A primary objective for accelerators at TUNL's Laboratory for Experimental Nuclear Astrophysics (LENA) is to maximize target beam intensity to ensure a high rate of nuclear events during each experiment. Average proton target currents of several mA are needed from LENA's electron cyclotron resonance (ECR) ion source because nuclear cross sections decrease substantially at energies of interest <200 keV. We seek to suppress undesired continuous environmental background by pulsing the beam and detecting events only during beam pulses. To improve beam intensity and transport, we installed a more powerful, stable microwave system for the ECR plasma, and will install a new acceleration system. This system will: reduce defocusing effects of the beam's internal space charge; provide better vacuum with a high gas conductance accelerating column; suppress bremsstrahlung X-rays produced when backstreaming electrons strike internal acceleration tube structures; and provide better heat dissipation by using deionized water to provide the current drain needed to establish the accelerating tube's voltage gradient. Details of beam optical modeling calculations, proposed accelerating tube design, and initial beam pulsing tests will be described. Work supported in part by USDOE Office of HE and Nuclear Physics.

Validation of Finite-Element Models of Persistent-Current Effects in Nb 3Sn Accelerator Magnets

DOE PAGES

Wang, X.; Ambrosio, G.; Chlachidze, G.; ...

2015-01-06

Persistent magnetization currents are induced in superconducting filaments during the current ramping in magnets. The resulting perturbation to the design magnetic field leads to field quality degradation, in particular at low field where the effect is stronger relative to the main field. The effects observed in NbTi accelerator magnets were reproduced well with the critical-state model. However, this approach becomes less accurate for the calculation of the persistent-current effects observed in Nb 3Sn accelerator magnets. Here a finite-element method based on the measured strand magnetization is validated against three state-of-art Nb3Sn accelerator magnets featuring different subelement diameters, critical currents, magnetmore » designs and measurement temperatures. The temperature dependence of the persistent-current effects is reproduced. Based on the validated model, the impact of conductor design on the persistent current effects is discussed. The performance, limitations and possible improvements of the approach are also discussed.« less

Electromagnetic Design of a Radiofrequency Cavity

NASA Astrophysics Data System (ADS)

Montoya Soto, G. R.; Duarte Galvan, Carlos; Monzon, Ildefonso Leon; Podesta Lerma, Pedro Luis manuel; Valerio-Lizarraga, C. A.

2017-10-01

Electromagnetic and mechanical studies have been performed with the aim of build a RF cavity in the S-Band (2998 MHz), the design takes into consideration the relativistic change in the electron velocity through the acceleration cavity. Four cavity cases were considered at different input energies, 50 KeV, 100 KeV, 150 KeV, with output energies of 350 KeV, the designs show good acceleration efficiency and beam coherence comparable to the one created in the cathode.

Investigation of using shrinking method in construction of Institute for Research in Fundamental Sciences Electron Linear Accelerator TW-tube (IPM TW-Linac tube)

NASA Astrophysics Data System (ADS)

Ghasemi, F.; Abbasi Davani, F.

2015-06-01

Due to Iran's growing need for accelerators in various applications, IPM's electron Linac project has been defined. This accelerator is a 15 MeV energy S-band traveling-wave accelerator which is being designed and constructed based on the klystron that has been built in Iran. Based on the design, operating mode is π /2 and the accelerating chamber consists of two 60cm long tubes with constant impedance and a 30cm long buncher. Amongst all construction methods, shrinking method is selected for construction of IPM's electron Linac tube because it has a simple procedure and there is no need for large vacuum or hydrogen furnaces. In this paper, different aspects of this method are investigated. According to the calculations, linear ratio of frequency alteration to radius change is 787.8 MHz/cm, and the maximum deformation at the tube wall where disks and the tube make contact is 2.7μ m. Applying shrinking method for construction of 8- and 24-cavity tubes results in satisfactory frequency and quality factor. Average deviations of cavities frequency of 8- and 24-cavity tubes to the design values are 0.68 MHz and 1.8 MHz respectively before tune and 0.2 MHz and 0.4 MHz after tune. Accelerating tubes, buncher, and high power couplers of IPM's electron linac are constructed using shrinking method.

A linear accelerator for simulated micrometeors.

NASA Technical Reports Server (NTRS)

Slattery, J. C.; Becker, D. G.; Hamermesh, B.; Roy, N. L.

1973-01-01

Review of the theory, design parameters, and construction details of a linear accelerator designed to impart meteoric velocities to charged microparticles in the 1- to 10-micron diameter range. The described linac is of the Sloan Lawrence type and, in a significant departure from conventional accelerator practice, is adapted to single particle operation by employing a square wave driving voltage with the frequency automatically adjusted from 12.5 to 125 kHz according to the variable velocity of each injected particle. Any output velocity up to about 30 km/sec can easily be selected, with a repetition rate of approximately two particles per minute.

Reactor for simulation and acceleration of solar ultraviolet damage

NASA Technical Reports Server (NTRS)

Laue, E.; Gupta, A.

1979-01-01

An environmental test chamber providing acceleration of UV radiation and precise temperature control (+ or -)1 C was designed, constructed and tested. This chamber allows acceleration of solar ultraviolet up to 30 suns while maintaining temperature of the absorbing surface at 30 C - 60 C. This test chamber utilizes a filtered medium pressure mercury arc as the source of radiation, and a combination of selenium radiometer and silicon radiometer to monitor solar ultraviolet (295-340 nm) and total radiant power output, respectively. Details of design and construction and operational procedures are presented along with typical test data.

An accelerated test design for use with synchronous orbit. [on Ni-Cd cell degradation behavior

NASA Technical Reports Server (NTRS)

Mcdermott, P. P.; Vasanth, K. L.

1980-01-01

The Naval Weapons Support Center at Crane, Indiana has conducted a large scale accelerated test of 6.0 Ah Ni-Cd cells. Data from the Crane test have been used to develop an equation for the description of Ni-Cd cell behavior in geosynchronous orbit. This equation relates the anticipated time to failure for a cell in synchronous orbit to temperature and overcharge rate sustained by the cell during the light period. A test design is suggested which uses this equation for setting test parameters for future accelerated testing.

Electromagnetic propulsion test facility

NASA Technical Reports Server (NTRS)

Gooder, S. T.

1984-01-01

A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.

Design details of Intelligent Instruments for PLC-free Cryogenic measurements, control and data acquisition

NASA Astrophysics Data System (ADS)

Antony, Joby; Mathuria, D. S.; Chaudhary, Anup; Datta, T. S.; Maity, T.

2017-02-01

Cryogenic network for linear accelerator operations demand a large number of Cryogenic sensors, associated instruments and other control-instrumentation to measure, monitor and control different cryogenic parameters remotely. Here we describe an alternate approach of six types of newly designed integrated intelligent cryogenic instruments called device-servers which has the complete circuitry for various sensor-front-end analog instrumentation and the common digital back-end http-server built together, to make crateless PLC-free model of controls and data acquisition. These identified instruments each sensor-specific viz. LHe server, LN2 Server, Control output server, Pressure server, Vacuum server and Temperature server are completely deployed over LAN for the cryogenic operations of IUAC linac (Inter University Accelerator Centre linear Accelerator), New Delhi. This indigenous design gives certain salient features like global connectivity, low cost due to crateless model, easy signal processing due to integrated design, less cabling and device-interconnectivity etc.

The Last Word: An Interview with Gene Chasin, CEO of Accelerated Schools Plus

ERIC Educational Resources Information Center

Siegle, Del

2006-01-01

This article presents an interview with Gene Chasin, CEO of Accelerated Schools Plus. Chasin discusses changing schools and improving student achievement. Accelerated Schools is a national endeavor that is designed to transform whole school communities. It views the community as being much broader. It includes students, teachers, parents, other…

Luis Alvarez, the Hydrogen Bubble Chamber, Tritium, and Dinosaurs

Science.gov Websites

linear accelerator, patented three types of radar still used today, designed an instrument that for 15 is available in documents and on the Web. Documents: Berkeley Proton Linear Accelerator, DOE Technical Report Download Adobe PDF Reader , June 1985 History of Proton Linear Accelerators, DOE Technical

Acceleration-Augmented LQG Control of an Active Magnetic Bearing

NASA Technical Reports Server (NTRS)

Feeley, Joseph J.

1993-01-01

A linear-quadratic-gaussian (LQG) regulator controller design for an acceleration-augmented active magnetic bearing (AMB) is outlined. Acceleration augmentation is a key feature in providing improved dynamic performance of the controller. The optimal control formulation provides a convenient method of trading-off fast transient response and force attenuation as control objectives.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Slawomir Alex

Here, we summarize current state of concept for muon acceleration aimed at future Neutrino Factory. The main thrust of these studies was to reduce the overall cost while maintaining performance through exploring interplay between complexity of the cooling systems and the acceptance of the accelerator complex. To ensure adequate survival of the short-lived muons, acceleration must occur at high average gradient. The need for large transverse and longitudinal acceptances drives the design of the acceleration system to initially low RF frequency, e.g. 325 MHz, and then increased to 650 MHz, as the transverse size shrinks with increasing energy. High-gradient normalmore » conducting RF cavities at these frequencies require extremely high peak-power RF sources. Hence superconducting RF (SRF) cavities are chosen. Here, we considered two cost effective schemes for accelerating muon beams for a stagable Neutrino Factory: Exploration of the so-called 'dual-use' linac concept, where the same linac structure is used for acceleration of both H- and muons and alternatively, the SRF efficient design based on multi-pass (4.5) 'dogbone' RLA, extendable to multi-pass FFAG-like arcs.« less

Estimation of payload loads using rigid body interface accelerations. [in structural design of launch vehicle systems

NASA Technical Reports Server (NTRS)

Chen, J. C.; Garba, J. A.; Wada, B. K.

1978-01-01

In the design/analysis process of a payload structural system, the accelerations at the payload/launch vehicle interface obtained from a system analysis using a rigid payload are often used as the input forcing function to the elastic payload to obtain structural design loads. Such an analysis is at best an approximation since the elastic coupling effects are neglected. This paper develops a method wherein the launch vehicle/rigid payload interface accelerations are modified to account for the payload elasticity. The advantage of the proposed method, which is exact to the extent that the physical system can be described by a truncated set of generalized coordinates, is that the complete design/analysis process can be performed within the organization responsible for the payload design. The method requires the updating of the system normal modes to account for payload changes, but does not require a complete transient solution using the composite system model. An application to a real complex structure, the Viking Spacecraft System, is given.

The detrimental effect of friction on space microgravity robotics

NASA Technical Reports Server (NTRS)

Newman, Wyatt S.; Glosser, Gregory D.; Miller, Jeffrey H.; Rohn, Douglas

1992-01-01

The authors present an analysis of why control systems are ineffective in compensating for acceleration disturbances due to Coulomb friction. Linear arguments indicate that the effects of Coulomb friction on a body are most difficult to reject when the control actuator is separated from the body of compliance. The linear arguments were illustrated in a nonlinear simulation of optimal linear tracking control in the presence of nonlinear friction. The results of endpoint acceleration measurements for four robot designs are presented and are compared with simulation and to equivalent measurements on a human. It is concluded that Coulomb friction in common bearings and transmission induces unacceptable levels of endpoint acceleration, that these accelerations cannot be adequately attenuated by control, and that robots for microgravity work will require special design considerations for inherently low friction.

Design and commissioning of a 16.1 MHz multiharmonic buncher for the reaccelerator at NSCL

NASA Astrophysics Data System (ADS)

Alt, Daniel Maloney

The ReAccelerator (ReA) linear accelerator facility at the National Superconducting Cyclotron Laboratory is a unique resource for the nuclear physics community. The particle fragmentation beam production technique, combined with the ability to stop and then reaccelerate the beam to energies of astrophysical interest, give experimenters an unprecedented range of rare isotopes at energies of nuclear and astrophysical interest. The ReAccelerator also functions as a testbed for technology to be incorporated in the upcoming Facility for Rare Isotope Beams linear accelerator, which will eventually in turn become the beam source for ReA. This prototype nature of the ReAccelerator, however, dictated some design choices which have resulted in a final beam with a time structure that is less than ideal for certain classes of experiments. The cavities and RFQ used in ReA have an operating frequency of 80.5 MHz, which corresponds to a separation between particle bunches at the detectors of 12.4 ns. While this separation is acceptable for many experiments, sensitive time of flight measurements require a greater separation between pulses. As nuclear physics experiments rely on statistics, a solution to increasing bunch separation without simply discarding a large fraction of the beam particles was desired. This document describes the design and construction of such a device, a 16.1 MHz multiharmonic buncher. The first chapter provides backgound information on the NSCL and ReA, and some basic concepts in accelerator physics to lay the groundwork for the project.Next, more specifics are provided on the time structure of accelerated beams, and the experimental motivation for greater separation. The third chapter outlines the basic principles of multiharmonic bunching. In order to evaluate the feasibility of any buncher design, the exact acceptance of the Radiofrequency Quadrupole (RFQ) of the ReAccelerator needed to be empirically measured. Chapter 4 describes the results of that measurement. Chapter 5 outlines the simulations and calculations that went into the design choices for this particular buncher, incorporating the results of the RFQ measurements. The next two chapters describe the construction, installation, and testing of the device, and give experimental results. Finally, Chapter 8 summarizes the project and the final steps which need to be undertaken to make the device a simple to use asset for future experimentalists at ReA.

The ASTRO-1 preliminary design review coupled load analysis

NASA Technical Reports Server (NTRS)

Mcghee, D. S.

1984-01-01

Results of the ASTRO-1 preliminary design review coupled loads analysis are presented. The M6.0Y Generic Shuttle mathematical models were used. Internal accelerations, interface forces, relative displacements, and net e.g., accelerations were recovered for two ASTRO-1 payloads in a tandem configuration. Twenty-seven load cases were computed and summarized. Load exceedences were found and recommendations made.

The International Linear Collider Technical Design Report - Volume 3.II: Accelerator Baseline Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adolphsen, Chris

2013-06-26

The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carriedmore » out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.« less

The International Linear Collider Technical Design Report - Volume 3.I: Accelerator \\& in the Technical Design Phase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adolphsen, Chris

2013-06-26

The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carriedmore » out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.« less

Start-to-end simulations for beam dynamics in the injector system of the KHIMA heavy ion accelerator

NASA Astrophysics Data System (ADS)

Lee, Yumi; Kim, Eun-San; Kim, Chanmi; Bahng, Jungbae; Li, Zhihui; Hahn, Garam

2017-07-01

The Korea Heavy Ion Medical Accelerator (KHIMA) project has been developed for cancer therapy. The injector system consists of a low energy beam transport (LEBT) line, a radio-frequency quadrupole, a drift tube linac with two tanks, and a medium energy beam transport (MEBT) line with a charge stripper section. The injector system transports and accelerates the 12C4+ beam that is produced from electron cyclotron resonance ion source up to 7 MeV/u, respectively. The 12C6+ beam, which is transformed by a charge stripper from the 12C4+ beam, is injected into a synchrotron and accelerated up to 430 MeV/u. The lattice for the injector system was designed to optimize the beam parameters and to meet beam requirements for the synchrotron. We performed start-to-end simulations from the LEBT line to the MEBT line to confirm that the required design goals of the beam and injector system were met. Our simulation results indicate that our design achieves the required performance and a good transmission efficiency of 90%. We present the lattice design and beam dynamics for the injector system in the KHIMA project.

Magnet design for the splitter/combiner regions of CBETA, the Cornell-Brookhaven Energy-Recovery-Linac Test Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crittendon, J. A.; Burke, D. C.; Fuentes, Y. L.P.

2017-01-06

The Cornell-Brookhaven Energy-Recovery-Linac Test Accelerator (CBETA) will provide a 150-MeV electron beam using four acceleration and four deceleration passes through the Cornell Main Linac Cryomodule housing six 1.3-GHz superconducting RF cavities. The return path of this 76-m-circumference accelerator will be provided by 106 fixed-field alternating-gradient (FFAG) cells which carry the four beams of 42, 78, 114 and 150 MeV. Here we describe magnet designs for the splitter and combiner regions which serve to match the on-axis linac beam to the off-axis beams in the FFAG cells, providing the path-length adjustment necessary to energy recovery for each of the four beams.more » The path lengths of the four beamlines in each of the splitter and combiner regions are designed to be adapted to 1-, 2-, 3-, and 4-pass staged operations. Design specifi- cations and modeling for the 24 dipole and 32 quadrupole electromagnets in each region are presented. The CBETA project will serve as the first demonstration of multi-pass energy recovery using superconducting RF cavities with FFAG cell optics for the return loop.« less

Basis for the power supply reliability study of the 1 MW neutron source

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGhee, D.G.; Fathizadeh, M.

1993-07-01

The Intense Pulsed Neutron Source (IPNS) upgrade to 1 MW requires new power supply designs. This paper describes the tools and the methodology needed to assess the reliability of the power supplies. Both the design and operation of the power supplies in the synchrotron will be taken into account. To develop a reliability budget, the experiments to be conducted with this accelerator are reviewed, and data is collected on the number and duration of interruptions possible before an experiment is required to start over. Once the budget is established, several accelerators of this type will be examined. The budget ismore » allocated to the different accelerator systems based on their operating experience. The accelerator data is usually in terms of machine availability and system down time. It takes into account mean time to failure (MTTF), time to diagnose, time to repair or replace the failed components, and time to get the machine back online. These estimated times are used as baselines for the design. Even though we are in the early stage of design, available data can be analyzed to estimate the MTTF for the power supplies.« less

A New Process for the Acceleration Test and Evaluation of Aeromedical Equipment for U.S. Air Force Safe-To-Fly Certification

DTIC Science & Technology

2010-10-01

4 8 4 | A Publication of the Defense Acquisition University http://www.dau.mil image designed by Miracle Riese » Keywords: Acceleration Test...Std Z39-18 4 8 6 | A Publication of the Defense Acquisition University http://www.dau.mil Generally speaking, medical devices are designed to...However, because the devices are designed for a controlled environment, concerns they may adversely affect the operation of aircraft systems must be

Crossbar H-mode drift-tube linac design with alternative phase focusing for muon linac

NASA Astrophysics Data System (ADS)

Otani, M.; Futatsukawa, K.; Hasegawa, K.; Kitamura, R.; Kondo, Y.; Kurennoy, S.

2017-07-01

We have developed a Crossbar H-mode (CH) drift-tube linac (DTL) design with an alternative phase focusing (APF) scheme for a muon linac, in order to measure the anomalous magnetic moment and electric dipole moment (EDM) of muons at the Japan Proton Accelerator Research Complex (J-PARC). The CH-DTL accelerates muons from β = v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. The design and results are described in this paper.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Kilean; Qiang, Ji

A recirculating superconducting linear accelerator with the advantage of both straight and circular accelerator has been demonstrated with relativistic electron beams. The acceleration concept of a recirculating proton beam was recently proposed and is currently under study. In order to further support the concept, the beam dynamics study on a recirculating proton linear accelerator has to be carried out. In this paper, we study the feasibility of a two-pass recirculating proton linear accelerator through the direct numerical beam dynamics design optimization and the start-to-end simulation. This study shows that the two-pass simultaneous focusing without particle losses is attainable including fullymore » 3D space-charge effects through the entire accelerator system.« less

An Accelerator Neutron Source for BNCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blue, Thomas, E

2006-03-14

The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability,more » and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.« less

Multiphysics Analysis of Frequency Detuning in Superconducting RF Cavities for Proton Particle Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Awida, M. H.; Gonin, I.; Passarelli, D.

2016-01-22

Multiphysics analyses for superconducting cavities are essential in the course of cavity design to meet stringent requirements on cavity frequency detuning. Superconducting RF cavities are the core accelerating elements in modern particle accelerators whether it is proton or electron machine, as they offer extremely high quality factors thus reducing the RF losses per cavity. However, the superior quality factor comes with the challenge of controlling the resonance frequency of the cavity within few tens of hertz bandwidth. In this paper, we investigate how the multiphysics analysis plays a major role in proactively minimizing sources of frequency detuning, specifically; microphonics andmore » Lorentz Force Detuning (LFD) in the stage of RF design of the cavity and mechanical design of the niobium shell and the helium vessel.« less

The new RLA test status

NASA Astrophysics Data System (ADS)

Smith, D. L.; Mazarakis, M. G.; Skogmo, P.; Bennett, L. F.; Olson, W. R.; George, M.; Harden, M. J.; Turman, B. N.; Moya, S. A.; Henderson, J. L.

The Recirculating Linear Accelerator (RLA) is returning to operation with a new relativistic electron beam (REB) injector and a modified accelerating cavity. Upon completion of our pulsed-power test program, we will capture the injected beam on an Ion Focussed Regime (IFR) guiding channel in either a spiral or a closed racetrack drift tube. The relativistic beam will recirculate for four passes through two accelerating cavities, in phase with the ringing cavity voltage, and increase to 8--12 MeV before being extracted. We designed the METGLAS ribbon-wound core, inductively isolated, four-stage injector to produce beam parameters of 4 MeV, 10--20 kA, and 40--55 ns FWHM. The three-line radial cavity is being modified to improve the 1-MV accelerating pulse shape while an advanced cavity design study is in progress. This is a continuation of the Sandia National Laboratory program to develop compact, high-voltage gradient, linear induction accelerators. The RLA concept is based on guiding an injected REB with an IFR channel. This channel is formed from a plasma created with a low energy electron beam inside a beam line containing about 2 x 10(exp -4) Torr of argon. The REB is injected onto the IFR channel and is transported down the beamline through a water dielectric accelerating cavity based on the ET-2 design. If the round-tip path of the beam matches the period of the cavity, the REB can be further accelerated by the ringing waveform on every subsequent pass. We have installed the new REB injector because we need a higher amplitude, longer duration, flat-topped pulse shape with a colder beam than that produced by the previous injector. We made extensive use of computer simulations in the form of network solver and electrostatic field stress analysis codes to aid in the design and modifications for the new RLA. The pulsed-power performance of the RLA injector and cavity and the associated driving hardware are discussed.

Applications of the Strategic Defense Initiative's compact accelerators

NASA Technical Reports Server (NTRS)

Montanarelli, Nick; Lynch, Ted

1991-01-01

The Strategic Defense Initiative's (SDI) investment in particle accelerator technology for its directed energy weapons program has produced breakthroughs in the size and power of new accelerators. These accelerators, in turn, have produced spinoffs in several areas: the radio frequency quadrupole linear accelerator (RFQ linac) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI-sponsored compact induction linear accelerator may replace Cobalt-60 radiation and hazardous ethylene-oxide as a method for sterilizing medical products, and other SDIO-funded accelerators may be used to produce the radioactive isotopes oxygen-15, nitrogen-13, carbon-11, and fluorine-18 for positron emission tomography (PET). Other applications of these accelerators include bomb detection, non-destructive inspection, decomposing toxic substances in contaminated ground water, and eliminating nuclear waste.

Effect of Exercise Program Speed, Agility, and Quickness (SAQ) in Improving Speed, Agility, and Acceleration

NASA Astrophysics Data System (ADS)

Azmi, K.; Kusnanik, N. W.

2018-01-01

This study aimed to analyze the effect of speed, agility and quickness training program to increase in speed, agility and acceleration. This study was conducted at 26 soccer players and divided into 2 groups with 13 players each group. Group 1 was given SAQ training program, and Group 2 conventional training program for 8 weeks. This study used a quantitative approach with quasi-experimental method. The design of this study used a matching-only design. Data was collected by testing 30-meter sprint (speed), agility t-test (agility), and run 10 meters (acceleration) during the pretest and posttest. Furthermore, the data was analyzed using paired sample t-test and independent t-test. The results showed: that there was a significant effect of speed, agility and quickness training program in improving in speed, agility and acceleration. In summary, it can be concluded that the speed, agility and quickness training program can improve the speed, agility and acceleration of the soccer players.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahl, P.F.

This year, 1992, marks the 65th anniversary of the publication of Rolf Wideroe`s doctoral dissertation. In it, he described not only the operating principles of the betatron, but also a working model of the first linear accelerator, constructed according to his own design. The latter, a resonance accelerator, gave Ernest Lawrence the idea for his cyclotron. Since Wideroe and his accelerator initiatives may not be very familiar to today`s accelerator physicists, the following is a brief recapitulation of the man and his work.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahl, P.F.

This year, 1992, marks the 65th anniversary of the publication of Rolf Wideroe's doctoral dissertation. In it, he described not only the operating principles of the betatron, but also a working model of the first linear accelerator, constructed according to his own design. The latter, a resonance accelerator, gave Ernest Lawrence the idea for his cyclotron. Since Wideroe and his accelerator initiatives may not be very familiar to today's accelerator physicists, the following is a brief recapitulation of the man and his work.

Accelerated approval of oncology products: a decade of experience.

PubMed

Dagher, Ramzi; Johnson, John; Williams, Grant; Keegan, Patricia; Pazdur, Richard

2004-10-20

We review the regulatory history of the accelerated approval process and summarize the U.S. Food and Drug Administration experience with accelerated approvals in oncology. The accelerated approval regulations, promulgated in 1992, allow approval of drugs for serious or life-threatening diseases on the basis of a surrogate endpoint that is reasonably likely to predict clinical benefit, such as survival or symptom benefit, pending completion of studies designed to confirm clinical benefit, referred to as phase 4 commitments, which are required to be conducted with due diligence. From 1992 to 2004, 22 applications involving anticancer drugs or biologics were approved. Of these 22 applications, accelerated approval was granted to 15 on the basis of findings from studies without an active comparator (i.e., single-arm studies or studies comparing two dose levels) and to the remaining seven on the basis of one or more randomized studies. Of the 22 approved applications, six (i.e., applications for dexrazoxane, irinotecan, capecitabine, docetaxel, imatinib mesylate, and oxaliplatin) have had one or more indications converted to regular approval. This review reports information that was presented at an Oncologic Drugs Advisory Committee meeting held in March 2003; it also presents a discussion of accelerated approval study designs, the study populations evaluated in the accelerated approval and confirmatory settings, and the integration of accelerated approval into a comprehensive drug development plan.

Plasma wakefield acceleration experiments at FACET II

NASA Astrophysics Data System (ADS)

Joshi, C.; Adli, E.; An, W.; Clayton, C. E.; Corde, S.; Gessner, S.; Hogan, M. J.; Litos, M.; Lu, W.; Marsh, K. A.; Mori, W. B.; Vafaei-Najafabadi, N.; O'shea, B.; Xu, Xinlu; White, G.; Yakimenko, V.

2018-03-01

During the past two decades of research, the ultra-relativistic beam-driven plasma wakefield accelerator (PWFA) concept has achieved many significant milestones. These include the demonstration of ultra-high gradient acceleration of electrons over meter-scale plasma accelerator structures, efficient acceleration of a narrow energy spread electron bunch at high-gradients, positron acceleration using wakes in uniform plasmas and in hollow plasma channels, and demonstrating that highly nonlinear wakes in the ‘blow-out regime’ have the electric field structure necessary for preserving the emittance of the accelerating bunch. A new 10 GeV electron beam facility, Facilities for Accelerator Science and Experimental Test (FACET) II, is currently under construction at SLAC National Accelerator Laboratory for the next generation of PWFA research and development. The FACET II beams will enable the simultaneous demonstration of substantial energy gain of a small emittance electron bunch while demonstrating an efficient transfer of energy from the drive to the trailing bunch. In this paper we first describe the capabilities of the FACET II facility. We then describe a series of PWFA experiments supported by numerical and particle-in-cell simulations designed to demonstrate plasma wake generation where the drive beam is nearly depleted of its energy, high efficiency acceleration of the trailing bunch while doubling its energy and ultimately, quantifying the emittance growth in a single stage of a PWFA that has optimally designed matching sections. We then briefly discuss other FACET II plasma-based experiments including in situ positron generation and acceleration, and several schemes that are promising for generating sub-micron emittance bunches that will ultimately be needed for both an early application of a PWFA and for a plasma-based future linear collider.

Plasma wakefield acceleration experiments at FACET II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, C.; Adli, E.; An, W.

During the past two decades of research, the ultra-relativistic beam-driven plasma wakefield accelerator (PWFA) concept has achieved many significant milestones. These include the demonstration of ultra-high gradient acceleration of electrons over meter-scale plasma accelerator structures, efficient acceleration of a narrow energy spread electron bunch at high-gradients, positron acceleration using wakes in uniform plasmas and in hollow plasma channels, and demonstrating that highly nonlinear wakes in the 'blow-out regime' have the electric field structure necessary for preserving the emittance of the accelerating bunch. A new 10 GeV electron beam facility, Facilities for Accelerator Science and Experimental Test (FACET) II, is currentlymore » under construction at SLAC National Accelerator Laboratory for the next generation of PWFA research and development. The FACET II beams will enable the simultaneous demonstration of substantial energy gain of a small emittance electron bunch while demonstrating an efficient transfer of energy from the drive to the trailing bunch. In this paper we first describe the capabilities of the FACET II facility. We then describe a series of PWFA experiments supported by numerical and particle-in-cell simulations designed to demonstrate plasma wake generation where the drive beam is nearly depleted of its energy, high efficiency acceleration of the trailing bunch while doubling its energy and ultimately, quantifying the emittance growth in a single stage of a PWFA that has optimally designed matching sections. Here, we briefly discuss other FACET II plasma-based experiments including in situ positron generation and acceleration, and several schemes that are promising for generating sub-micron emittance bunches that will ultimately be needed for both an early application of a PWFA and for a plasma-based future linear collider.« less

Plasma wakefield acceleration experiments at FACET II

DOE PAGES

Joshi, C.; Adli, E.; An, W.; ...

2018-01-12

During the past two decades of research, the ultra-relativistic beam-driven plasma wakefield accelerator (PWFA) concept has achieved many significant milestones. These include the demonstration of ultra-high gradient acceleration of electrons over meter-scale plasma accelerator structures, efficient acceleration of a narrow energy spread electron bunch at high-gradients, positron acceleration using wakes in uniform plasmas and in hollow plasma channels, and demonstrating that highly nonlinear wakes in the 'blow-out regime' have the electric field structure necessary for preserving the emittance of the accelerating bunch. A new 10 GeV electron beam facility, Facilities for Accelerator Science and Experimental Test (FACET) II, is currentlymore » under construction at SLAC National Accelerator Laboratory for the next generation of PWFA research and development. The FACET II beams will enable the simultaneous demonstration of substantial energy gain of a small emittance electron bunch while demonstrating an efficient transfer of energy from the drive to the trailing bunch. In this paper we first describe the capabilities of the FACET II facility. We then describe a series of PWFA experiments supported by numerical and particle-in-cell simulations designed to demonstrate plasma wake generation where the drive beam is nearly depleted of its energy, high efficiency acceleration of the trailing bunch while doubling its energy and ultimately, quantifying the emittance growth in a single stage of a PWFA that has optimally designed matching sections. Here, we briefly discuss other FACET II plasma-based experiments including in situ positron generation and acceleration, and several schemes that are promising for generating sub-micron emittance bunches that will ultimately be needed for both an early application of a PWFA and for a plasma-based future linear collider.« less

High Efficiency Electron-Laser Interactions in Tapered Helical Undulators

NASA Astrophysics Data System (ADS)

Duris, Joseph Patrick

Efficient coupling of relativistic electron beams with high power radiation lies at the heart of advanced accelerator and light source research and development. The inverse free electron laser is a stable accelerator capable of harnessing very high intensity laser electric fields to efficiently transfer large powers from lasers to electron beams. In this dissertation, we first present the theoretical framework to describe the interaction, and then apply our improved understanding of the IFEL to the design and numerical study of meter-long, GeV IFELs for compact light sources. The central experimental work of the dissertation is the UCLA BNL helical inverse free electron laser experiment at the Accelerator Test Facility in Brookhaven National Laboratory which used a strongly tapered 54cm long, helical, permanent magnet undulator and a several hundred GW CO2 laser to accelerate electrons from 52 to 106MeV, setting new records for inverse free electron laser energy gain (54MeV) and average accelerating gradient (100MeV/m). The undulator design and fabrication as well as experimental diagnostics are presented. In order to improve the stability and quality of the accelerated electron beam, we redesigned the undulator for a slightly reduced output energy by modifying the magnet gap throughout the undulator, and we used this modified undulator to demonstrated capture of >25% of the injected beam without prebunching. In the study of heavily loaded GeV inverse free electron lasers, we show that a majority of the power may be transferred from a laser to the accelerated electron beam. Reversing the process to decelerate high power electron beams, a mechanism we refer to as tapering enhanced stimulated superradiant amplification, offers a clear path to high power light sources. We present studies of radiation production for a wide range of wavelengths (10mum, 13nm, and 0.3nm) using this method and discuss the design for a deceleration experiment using the same undulator used for acceleration in this experiment. By accounting for the evolving radiation field in the design of the undulator tapering, a large fraction of energy may be transferred between the electrons and laser, enabling compact, high-current GeV accelerators and various wavelength light-sources of unprecedented peak powers.

Beam dynamics simulation of a double pass proton linear accelerator

DOE PAGES

Hwang, Kilean; Qiang, Ji

2017-04-03

A recirculating superconducting linear accelerator with the advantage of both straight and circular accelerator has been demonstrated with relativistic electron beams. The acceleration concept of a recirculating proton beam was recently proposed and is currently under study. In order to further support the concept, the beam dynamics study on a recirculating proton linear accelerator has to be carried out. In this paper, we study the feasibility of a two-pass recirculating proton linear accelerator through the direct numerical beam dynamics design optimization and the start-to-end simulation. This study shows that the two-pass simultaneous focusing without particle losses is attainable including fullymore » 3D space-charge effects through the entire accelerator system.« less

Accelerator shield design of KIPT neutron source facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Z.; Gohar, Y.

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of a neutron source facility at KIPT utilizing an electron-accelerator-driven subcritical assembly. Electron beam power is 100 kW, using 100 MeV electrons. The facility is designed to perform basic and applied nuclear research, produce medical isotopes, and train young nuclear specialists. The biological shield of the accelerator building is designed to reduce the biological dose to less than 0.5-mrem/hr during operation. The main source of the biological dose is the photons and the neutrons generatedmore » by interactions of leaked electrons from the electron gun and accelerator sections with the surrounding concrete and accelerator materials. The Monte Carlo code MCNPX serves as the calculation tool for the shield design, due to its capability to transport electrons, photons, and neutrons coupled problems. The direct photon dose can be tallied by MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is less than 0.01 neutron per electron. This causes difficulties for Monte Carlo analyses and consumes tremendous computation time for tallying with acceptable statistics the neutron dose outside the shield boundary. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were developed for the study. The generated neutrons are banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron and secondary photon doses. The weight windows variance reduction technique is utilized for both neutron and photon dose calculations. Two shielding materials, i.e., heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary at less than 0.5-mrem/hr. The shield configuration and parameters of the accelerator building have been determined and are presented in this paper. (authors)« less

Radiation protection and environmental management at the relativistic heavy ion collider.

PubMed

Musolino, S V; Briggs, S L; Stevens, A J

2001-01-01

The Relativistic Heavy Ion Collider (RHIC) is a high energy hadron accelerator built to study basic nuclear physics. It consists of two counter-rotating beams of fully stripped gold ions that are accelerated in two rings to an energy of 100 GeV/nucleon or protons at 250 GeV/c. The beams can be stored for a period of five to ten hours and brought into collision for experiments during that time. The first major physics objective is to recreate a state of matter, the quark-gluon plasma, that has been predicted to have existed at a short time after the creation of the universe. Because there are only a few other high energy particle accelerators like RHIC in the world, the rules promulgated in the US Code of Federal Regulations under the Atomic Energy Act, State regulations, or international guidance documents do not cover prompt radiation from accelerators to govern directly the design and operation of a superconducting collider. Special design criteria for prompt radiation were developed to provide guidance tor the design of radiation shielding. Environmental Management at RHIC is accomplished through the ISO 14001 Environmental Management System. The applicability, benefits, and implementation of ISO 14001 within the framework of a large research accelerator complex are discussed in the paper.

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. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Plug-in module acceleration feedback control for fast steering mirror-based beam stabilization systems

NASA Astrophysics Data System (ADS)

Deng, Chao; Ren, Wei; Mao, Yao; Ren, Ge

2017-08-01

A plug-in module acceleration feedback control (Plug-In AFC) strategy based on the disturbance observer (DOB) principle is proposed for charge-coupled device (CCD)-based fast steering mirror (FSM) stabilization systems. In classical FSM tracking systems, dual-loop control (DLC), including velocity feedback and position feedback, is usually utilized to enhance the closed-loop performance. Due to the mechanical resonance of the system and CCD time delay, the closed-loop bandwidth is severely restricted. To solve this problem, cascade acceleration feedback control (AFC), which is a kind of high-precision robust control method, is introduced to strengthen the disturbance rejection property. However, in practical applications, it is difficult to realize an integral algorithm in an acceleration controller to compensate for the quadratic differential contained in the FSM acceleration model, resulting in a challenging controller design and a limited improvement. To optimize the acceleration feedback framework in the FSM system, different from the cascade AFC, the accelerometers are used to construct DOB to compensate for the platform vibrations directly. The acceleration nested loop can be plugged into the velocity loop without changing the system stability, and the controller design is quite simple. A series of comparative experimental results demonstrate that the disturbance rejection property of the CCD-based FSM can be effectively improved by the proposed approach.

The conversion of CESR to operate as the Test Accelerator, CesrTA. Part 1: overview

NASA Astrophysics Data System (ADS)

Billing, M. G.

2015-07-01

Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper outlines the motivation, design and conversion of CESR to a test accelerator, CESRTA, enhanced to study such subjects as low emittance tuning methods, electron cloud (EC) effects, intra-beam scattering, fast ion instabilities as well as general improvements to beam instrumentation. While the initial studies of CESRTA focussed on questions related to the International Linear Collider (ILC) damping ring design, CESRTA is a very flexible storage ring, capable of studying a wide range of accelerator physics and instrumentation questions. This paper contains the outline and the basis for a set of papers documenting the reconfiguration of the storage ring and the associated instrumentation required for the studies described above. Further details may be found in these papers.

Chaotic dynamical aperture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.Y.; Tepikian, S.

1985-01-01

Nonlinear magnetic forces become more important for particles in the modern large accelerators. These nonlinear elements are introduced either intentionally to control beam dynamics or by uncontrollable random errors. Equations of motion in the nonlinear Hamiltonian are usually non-integrable. Because of the nonlinear part of the Hamiltonian, the tune diagram of accelerators is a jungle. Nonlinear magnet multipoles are important in keeping the accelerator operation point in the safe quarter of the hostile jungle of resonant tunes. Indeed, all the modern accelerator designs have taken advantages of nonlinear mechanics. On the other hand, the effect of the uncontrollable random multipolesmore » should be evaluated carefully. A powerful method of studying the effect of these nonlinear multipoles is using a particle tracking calculation, where a group of test particles are tracing through these magnetic multipoles in the accelerator hundreds to millions of turns in order to test the dynamical aperture of the machine. These methods are extremely useful in the design of a large accelerator such as SSC, LEP, HERA and RHIC. These calculations unfortunately take a tremendous amount of computing time. In this review the method of determining chaotic orbit and applying the method to nonlinear problems in accelerator physics is discussed. We then discuss the scaling properties and effect of random sextupoles.« less

Neutral Orbital Altitude Density Effects on the International Space Station

NASA Technical Reports Server (NTRS)

Smith, O.E.; Adelfang, S. I.; Smith, R. E.

1997-01-01

One of the design requirements of the International Space Station (ISS) is that each year accelerations of one micro-g cannot be exceeded at the ISS internal payload location for 6 periods of not less than 30 consecutive days. Although there are other causes, this study deals only with the accelerations caused by atmospheric drag. The critical ambient neutral density, computed using the Marshall Engineering Thermosphere Model, required to produce accelerations of one micro-g on the ISS, is estimated using an atmospheric drag acceleration equation. Results show that the design requirements may be difficult to meet during periods of extremely high solar activity; the planned reboost and altitude strategies for the ISS may have to be revised to allow for the uncertainty in the prediction of neutral atmospheric density within the 100-day period established for orbital decay before reboost.

Adaptive Control for Microgravity Vibration Isolation System

NASA Technical Reports Server (NTRS)

Yang, Bong-Jun; Calise, Anthony J.; Craig, James I.; Whorton, Mark S.

2005-01-01

Most active vibration isolation systems that try to a provide quiescent acceleration environment for space science experiments have utilized linear design methods. In this paper, we address adaptive control augmentation of an existing classical controller that employs a high-gain acceleration feedback together with a low-gain position feedback to center the isolated platform. The control design feature includes parametric and dynamic uncertainties because the hardware of the isolation system is built as a payload-level isolator, and the acceleration Sensor exhibits a significant bias. A neural network is incorporated to adaptively compensate for the system uncertainties, and a high-pass filter is introduced to mitigate the effect of the measurement bias. Simulations show that the adaptive control improves the performance of the existing acceleration controller and keep the level of the isolated platform deviation to that of the existing control system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, K. A.; Schoefer, V.; Tomizawa, M.

The new accelerator complex at J-PARC will operate with both high energy and very high intensity proton beams. With a design slow extraction efficiency of greater than 99% this facility will still be depositing significant beam power onto accelerator components [2]. To achieve even higher efficiencies requires some new ideas. The design of the extraction system and the accelerator lattice structure leaves little room for improvement using conventional techniques. In this report we will present one method for improving the slow extraction efficiency at J-PARC by adding duodecapoles or octupoles to the slow extraction system. We will review the theorymore » of resonant extraction, describe simulation methods, and present the results of detailed simulations. From our investigations we find that we can improve extraction efficiency and thereby reduce the level of residual activation in the accelerator components and surrounding shielding.« less

Lattice Design for a High-Power Infrared FEL

NASA Astrophysics Data System (ADS)

Douglas, D. R.

1997-05-01

A 1 kW infrared FEL, funded by the U.S. Navy, is under construction at Jefferson Lab. This device will be driven by a compact, 42 MeV, 5 mA, energy-recovering, CW SRF-based linear accelerator to produce light in the 3-6.6 μm range. The machine concept comprises a 10 MeV injector, a linac based on a single high-gradient Jefferson Lab accelerator cryomodule, a wiggler and optical cavity, and an energy-recovery recirculation arc. Energy recovery limits cost and technical risk by reducing the RF power requirements in the driver accelerator. Following deceleration to 10 MeV, the beam is dumped. Stringent phase space requirements at the wiggler, low beam energy, and high beam current subject the accelerator lattice to numerous constraints. Principal considerations include: transport and delivery to the FEL of a high-quality, high-current beam; the impact of coherent synchrotron radiation (CSR) during beam recirculation transport; beam optics aberration control, to provide low-loss energy-recovery transport of a 5% relative momentum spread, high-current beam; attention to possible beam breakup (BBU) instabilities in the recirculating accelerator; and longitudinal phase space management during beam transport, to optimize RF drive system control during energy recovery and FEL operation. The presentation will address the design process and design solution for an accelerator transport lattice that meets the requirements imposed by these physical phenomena and operational necessities.

A Variable Energy CW Compact Accelerator for Ion Cancer Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnstone, Carol J.; Taylor, J.; Edgecock, R.

2016-03-10

Cancer is the second-largest cause of death in the U.S. and approximately two-thirds of all cancer patients will receive radiation therapy with the majority of the radiation treatments performed using x-rays produced by electron linacs. Charged particle beam radiation therapy, both protons and light ions, however, offers advantageous physical-dose distributions over conventional photon radiotherapy, and, for particles heavier than protons, a significant biological advantage. Despite recognition of potential advantages, there is almost no research activity in this field in the U.S. due to the lack of clinical accelerator facilities offering light ion therapy in the States. In January, 2013, amore » joint DOE/NCI workshop was convened to address the challenges of light ion therapy [1], inviting more than 60 experts from diverse fields related to radiation therapy. This paper reports on the conclusions of the workshop, then translates the clinical requirements into accelerat or and beam-delivery technical specifications. A comparison of available or feasible accelerator technologies is compared, including a new concept for a compact, CW, and variable energy light ion accelerator currently under development. This new light ion accelerator is based on advances in nonscaling Fixed-Field Alternating gradient (FFAG) accelerator design. The new design concepts combine isochronous orbits with long (up to 4m) straight sections in a compact racetrack format allowing inner circulating orbits to be energy selected for low-loss, CW extraction, effectively eliminating the high-loss energy degrader in conventional CW cyclotron designs.« less

Field stabilization studies for a radio frequency quadrupole accelerator

NASA Astrophysics Data System (ADS)

Gaur, R.; Kumar, V.

2014-07-01

The Radio Frequency Quadrupole (RFQ) linear accelerator is an accelerator that efficiently focuses, bunches and accelerates a high intensity DC beam from an ion source, for various applications. Unlike other conventional RF linear accelerators, the electromagnetic mode used for its operation is not the lowest frequency mode supported by the structure. In a four vane type RFQ, there are several undesired electromagnetic modes having frequency close to that of the operating mode. While designing an RFQ accelerator, care must be taken to ensure that the frequencies of these nearby modes are sufficiently separated from the operating mode. If the undesired nearby modes have frequencies close to the operating mode, the electromagnetic field pattern in the presence of geometrical errors will not be stabilized to the desired field profile, and will be perturbed by the nearby modes. This will affect the beam dynamics and reduce the beam transmission. In this paper, we present a detailed study of the electromagnetic modes supported, which is followed by calculations for implementation of suitable techniques to make the desired operating mode stable against mixing with unwanted modes for an RFQ being designed for the proposed Indian Spallation Neutron Source (ISNS) project at Raja Ramanna Centre for Advanced Technology, Indore. Resonant coupling scheme, along with dipole stabilization rods has been proposed to increase the mode separation. The paper discusses the details of a generalized optimization procedure that has been used for the design of mode stabilization scheme.

Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganni, Venkatarao; Knudsen, Peter N.; Arenius, Dana M.

The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.

Development of Bipolar Pulse Accelerator for Pulsed Ion Beam Implantation to Semiconductor

NASA Astrophysics Data System (ADS)

Masugata, Katsumi; Kawahara, Yoshihiro; Mitsui, Chihiro; Kitamura, Iwao; Takahashi, Takakazu; Tanaka, Yasunori; Tanoue, Hisao; Arai, Kazuo

2002-12-01

To improve the purity of the ion beams new type of pulsed power ion accelerator named "bipolar pulse accelerator" was proposed. The accelerator consists of two acceleration gaps (an ion source gap and a post acceleration gap) and a drift tube, and a bipolar pulse is applied to the drift tube to accelerate the beam. In the accelerator intended ions are selectively accelerated and the purity of the ion beam is enhanced. As the first step of the development of the accelerator, a Br-type magnetically insulated acceleration gap is developed. The gap has an ion source of coaxial gas puff plasma gun on the grounded anode and a negative pulse is applied to the cathode to accelerate the ion beam. By using the plasma gun, ion source plasma (nitrogen) of current density around 100 A/cm2 is obtained. In the paper, the experimental results of the evaluation of the ion beam and the characteristics of the gap are shown with the principle and the design concept of the proposed accelerator.

Improvements of the magnetic field design for SPIDER and MITICA negative ion beam sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chitarin, G., E-mail: chitarin@igi.cnr.it; University of Padova, Dept. of Management and Engineering, Strad. S. Nicola 3, 36100 Vicenza; Agostinetti, P.

2015-04-08

The design of the magnetic field configuration in the SPIDER and MITICA negative ion beam sources has evolved considerably during the past four years. This evolution was driven by three factors: 1) the experimental results of the large RF-driven ion sources at IPP, which have provided valuable indications on the optimal magnetic configurations for reliable RF plasma source operation and for large negative ion current extraction, 2) the comprehensive beam optics and heat load simulations, which showed that the magnetic field configuration in the accelerator is crucial for keeping the heat load due to electrons on the accelerator grids withinmore » tolerable limits, without compromising the optics of the negative ion beam in the foreseen operating scenarios, 3) the progress of the detailed mechanical design of the accelerator, which stimulated the evaluation of different solutions for the correction of beamlet deflections of various origin and for beamlet aiming. On this basis, new requirements and solution concepts for the magnetic field configuration in the SPIDER and MITICA beam sources have been progressively introduced and updated until the design converged. The paper presents how these concepts have been integrated into a final design solution based on a horizontal “long-range” field (few mT) in combination with a “local” vertical field of some tens of mT on the acceleration grids.« less

RF conditioning and beam experiments on 400 keV RFQ accelerator at BARC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Shrikrishna; Rao, S.V.L.S.; Kumar, Rajesh, E-mail: sgupta@barc.gov.in

2014-07-01

A 400 keV Radio-frequency quadrupole accelerator (RFQ) has been designed, developed and tested at BARC. This will be used as a neutron generator (via D-T reaction). The RFQ operates at a resonant frequency of 350 MHz and needs an RF power of ∼ 60 kW to accelerate the deuteron beam to 400 keV within a length of 1.03 m. Though the RFQ is designed for deuteron beam, it was tested by accelerating both the proton and deuteron beams to their designed values of 200 and 400 keV respectively. The proton and deuteron beam experiments required peak RF power of approx.more » 15 kW and 60 kW respectively at 350 MHz. The RF power from the tetrode amplifier and coaxial transmission lines is coupled to the cavity by a coaxial loop coupler. As the coupler and cavity operated at vacuum of better than 2e-6 torr, extensive RF conditioning of the cavity and coupler was performed to reach at the desired power levels. (author)« less

The light ion pulsed power induction accelerator for ETF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazarakis, M.G.; Olson, R.E.; Olson, C.L.

1994-12-31

Our Engineering Test Facility (ETF) driver concept is based on HERMES III and RHEPP technologies. Actually, it is a scaled-down version of the LMF design incorporating repetition rate capabilities of up to 10 Hz CW. The preconceptual design presented here provides 200-TW peak power to the ETF target during 10 ns, equal to 2-MJ total ion beam energy. Linear inductive voltage addition driving a self-magnetically insulated transmission line (MITL) is utilized to generate the 36-MV peak voltage needed for lithium ion beams. The {approximately} 3-MA ion current is achieved by utilizing many accelerating modules in parallel. Since the current permore » module is relatively modest ({approximately}300 kA), two-stage or one-stage extraction diodes can be utilized for the generation of singly charged lithium ions. The accelerating modules are arranged symmetrically around the fusion chamber in order to provide uniform irradiation onto the ETF target. In addition, the modules are fired in a programmed sequence in order to generate the optimum power pulse shape onto the target. This design utilizes RHEPP accelerator modules as the principal power source.« less

Design of a Microwave Assisted Discharge Inductive Plasma Accelerator

NASA Technical Reports Server (NTRS)

Hallock, Ashley K.; Polzin, Kurt A.

2010-01-01

The design and construction of a thruster that employs electrodeless plasma preionization and pulsed inductive acceleration is described. Preionization is achieved through an electron cyclotron resonance discharge that produces a weakly-ionized plasma at the face of a conical theta pinch-shaped inductive coil. The presence of the preionized plasma allows for current sheet formation at lower discharge voltages than those employed in other pulsed inductive accelerators that do not employ preionization. The location of the electron cyclotron resonance discharge is controlled through the design of the applied magnetic field in the thruster. Finite element analysis shows that there is an arrangement of permanent magnets that yields a small volume of resonant magnetic field at the coil face. Preionization in the resonant zone leads to current sheet formation at the coil face, which minimizes the initial inductance of the pulse circuit and maximizes the potential electrical efficiency of the accelerator. A magnet assembly was constructed around an inductive coil to provide structural support to the selected arrangement of neodymium magnets. Measured values of the resulting magnetic field compare favorably with the finite element model.

Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator.

PubMed

Chitarin, G; Agostinetti, P; Marconato, N; Marcuzzi, D; Sartori, E; Serianni, G; Sonato, P

2012-02-01

The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

A CW FFAG for Proton Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnstone, C.; Neuffer, D. V.; Snopok, P.

2012-05-01

An advantage of the cyclotron in proton therapy is the continuous (CW) beam output which reduces complexity and response time in the dosimetry requirements and beam controls. A CW accelerator requires isochronous particle orbits at all energie s through the acceleration cycle and present compact isochronous cyclotrons for proton therapy reach only 250 MeV (kinetic energy) which is required for patient treatment, but low for full Proton Computed Tomography (PCT) capability. PCT specifications ne ed 300-330 MeV in order for protons to transit the human body. Recent innovations in nonscaling FFAG design have achieved isochronous performance in a compact (~3more » m radius) design at these higher energies. Preliminary isochronous designs are presented her e. Lower energy beams can be efficiently extracted for patient treatment without changes to the acceleration cycle and magnet currents.« less

Cyclotrons and FFAG Accelerators as Drivers for ADS

DOE PAGES

Calabretta, Luciano; Méot, François

2015-01-01

Our review summarizes projects and studies on circular accelerators proposed for driving subcritical reactors. The early isochronous cyclotron cascades, proposed about 20 years ago, and the evolution of these layouts up to the most recent solutions or designs based on cyclotrons and fixed field alternating gradient accelerators, are reported. Additionally, the newest ideas and their prospects for development are discussed.

Lo Que los Padres y los Maestros Deberian Saber sobre la...Aceleraction (What Parents and Teachers Should Know about Academic Acceleration).

ERIC Educational Resources Information Center

Guenther, Alex

Designed for Spanish-speaking educators and parents, this pamphlet discusses academic acceleration for gifted children. Major types of academic acceleration and their benefits are described. These include: (1) early admission to kindergarten that saves parents of gifted children the expenses of a year of preschool, allows children to be…

Rare isotope accelerator project in Korea and its application to high energy density sciences

NASA Astrophysics Data System (ADS)

Chung, M.; Chung, Y. S.; Kim, S. K.; Lee, B. J.; Hoffmann, D. H. H.

2014-01-01

As a national science project, the Korean government has recently established the Institute for Basic Science (IBS) with the goal of conducting world-class research in basic sciences. One of the core facilities for the IBS will be the rare isotope accelerator which can produce high-intensity rare isotope beams to investigate the fundamental properties of nature, and also to support a broad research program in material sciences, medical and biosciences, and future nuclear energy technologies. The construction of the accelerator is scheduled to be completed by approximately 2017. The design of the accelerator complex is optimized to deliver high average beam current on targets, and to maximize the production of rare isotope beams through the simultaneous use of Isotope Separation On-Line (ISOL) and In-Flight Fragmentation (IFF) methods. The proposed accelerator is, however, not optimal for high energy density science, which usually requires very high peak currents on the target. In this study, we present possible beam-plasma experiments that can be done within the scope of the current accelerator design, and we also investigate possible future extension paths that may enable high energy density science with intense pulsed heavy ion beams.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leitner, M.; Bieniosek, F.; Kwan, J.

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL), a collaboration between Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and Princeton Plasma Physics Laboratory (PPPL), is currently constructing a new induction linear accelerator, called Neutralized Drift Compression eXperiment NDCX-II. The accelerator design makes effective use of existing components from LLNL's decommissioned Advanced Test Accelerator (ATA), especially induction cells and Blumlein voltage sources that have been transferred to LBNL. We have developed an aggressive acceleration 'schedule' that compresses the emitted ion pulse from 500 ns to 1 ns in just 15 meters. In the nominal design concept, 30more » nC of Li{sup +} are accelerated to 3.5 MeV and allowed to drift-compress to a peak current of about 30 A. That beam will be utilized for warm dense matter experiments investigating the interaction of ion beams with matter at high temperature and pressure. Construction of the accelerator will be complete within a period of approximately two and a half years and will provide a worldwide unique opportunity for ion-driven warm dense matter experiments as well as research related to novel beam manipulations for heavy ion fusion drivers.« less

Acceleration lane design for higher truck volumes.

DOT National Transportation Integrated Search

2008-12-09

The research project examined attributes associated with tractor-trailer trucks accelerating on freeway entry ramps and : entering the main traffic lanes. Data for this project were collected at five commercial vehicle weigh stations in : Arkansas an...

Design study of a radio-frequency quadrupole for high-intensity beams

NASA Astrophysics Data System (ADS)

Bahng, Jungbae; Kim, Eun-San; Choi, Bong-Hyuk

2017-07-01

The Rare isotope Accelerator Of Newness (RAON) heavy-ion accelerator has been designed for the Rare Isotope Science Project (RISP) in Korea. The RAON will produce heavy-ion beams from 660-MeV-proton to 200-MeV/u-uranium with continuous wave (CW) power of 400 kW to support research in various scientific fields. Its system consists of an ECR ion source, LEBTs with 10 keV/u, CW RFQ accelerator with 81.25 MHz and 500 keV/u, a MEBT system, and a SC linac. In detail, the driver linac system consists of a Quarter Wave Resonator (QWR) section with 81.25 MHz and a Half Wave Resonator (HWR) section with 162.5 MHz, Linac-1, and a Spoke Cavity section with 325 MHz, Linac-2. These linacs have been designed to optimize the beam parameters to meet the required design goals. At the same time, a light-heavy ion accelerator with high-intensity beam, such as proton, deuteron, and helium beams, is required for experiments. In this paper, we present the design study of the high intensity RFQ for a deuteron beam with energies from 30 keV/u to 1.5 MeV/u and currents in the mA range. This system is composed of an Penning Ionization Gauge ion source, short LEBT with a RF deflector, and shared SC Linac. In order to increase acceleration efficiency in a short length with low cost, the 2nd harmonic of 162.5 MHz is applied as the operation frequency in the D+ RFQ design. The D+ RFQ is designed with 4.97 m, 1.52 bravery factor. Since it operates with 2nd harmonic frequency, the beam should be 50% of the duty factor while the cavity should be operated in CW mode, to protect the downstream linac system. We focus on avoiding emittance growth by the space-charge effect and optimizing the RFQ to achieve a high transmission and low emittance growth. Both the RFQ beam dynamics study and RFQ cavity design study for two and three dimensions will be discussed. Supported by Korea University Future Research Grant

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

DOE PAGES

Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

2014-07-28

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

Accelerating gradient improvement from hole-boring to light-sail stage using shape-tailored laser front

NASA Astrophysics Data System (ADS)

Wang, W. P.; Shen, B. F.; Xu, Z. Z.

2017-01-01

The accelerating gradient of a proton beam is a crucial factor for the stable radiation pressure acceleration, because quickly accelerating protons into the relativistic region may reduce the multidimensional instability grow to a certain extent. In this letter, a shape-tailored laser is designed to accelerate the protons in a controllable high accelerating gradient in theory. Finally, a proton beam in the gigaelectronvolt range with an energy spread of ˜2.4% is obtained in one-dimensional particle-in-cell simulations. With the future development of the high-intense laser, the ability to accelerate a high energy proton beam using a shape-tailored laser will be important for realistic proton applications, such as fast ignition for inertial confinement fusion, medical therapy, and proton imaging.

Design of a diamond-crystal monochromator for the LCLS hard x-ray self-seeding project

NASA Astrophysics Data System (ADS)

Shu, D.; Shvyd'ko, Y.; Amann, J.; Emma, P.; Stoupin, S.; Quintana, J.

2013-03-01

As the result of collaborations between the Advanced Photon Source (APS), Argonne National Laboratory, and the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory, we have designed and constructed a diamond crystal monochromator for the LCLS hard x-ray self-seeding project. The novel monochromator is ultrahigh-vacuum compatible to meet the LCLS linear accelerator vacuum environmental requirement. A special graphite holder was designed for strain-free mount of the 110-μm thin synthetic diamond crystal plate provided by Technological Institute for Super-hard and Novel Carbon Materials of Russia (TISNCM). An in-vacuum multi-axis precision positioning mechanism is designed to manipulate the thin-film diamond holder with resolutions and stabilities required by the hard x-ray self-seeding physics. Optical encoders, limit switches, and hardware stops are established in the mechanism to ensure system reliability and to meet the accelerator personal and equipment safety interlock requirements. Molybdenum shields are installed in the monochromator to protect the encoders and associated electronics from radiation damage. Mechanical specifications, designs, and preliminary test results of the diamond monochromator are presented in this paper.

Microgravity acceleration measurement and environment characterization science (17-IML-1)

NASA Technical Reports Server (NTRS)

1992-01-01

The Space Acceleration Measurement System (SAMS) is a general purpose instrumentation system designed to measure the accelerations onboard the Shuttle Orbiter and Shuttle/Spacelab vehicles. These measurements are used to support microgravity experiments and investigation into the microgravity environment of the vehicle. Acceleration measurements can be made at locations remote from the SAMS main instrumentation unit by the use of up to three remote triaxial sensor heads. The prime objective for SAMS on the International Microgravity Lab (IML-1) mission will be to measure the accelerations experienced by the Fluid Experiment System (FES). The SAMS acceleration measurements for FES will be complemented by low level, low frequency acceleration measurements made by the Orbital Acceleration Research Experiment (OARE) installed on the shuttle. Secondary objectives for SAMS will be to measure accelerations at several specific locations to enable the acceleration transfer function of the Spacelab module to be analyzed. This analysis effort will be in conjunction with similar measurements analyses on other Spacelab missions.

TU-H-BRA-06: Characterization of a Linear Accelerator Operating in a Compact MRIGuided Radiation Therapy System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, O; Mutic, S; Li, H

2016-06-15

Purpose: To describe the performance of a linear accelerator operating in a compact MRI-guided radiation therapy system. Methods: A commercial linear accelerator was placed in an MRI unit that is employed in a commercial MR-based image guided radiation therapy (IGRT) system. The linear accelerator components were placed within magnetic field-reducing hardware that provided magnetic fields of less than 40 G for the magnetron, gun driver, and port circulator, with 1 G for the linear accelerator. The system did not employ a flattening filter. The test linear accelerator was an industrial 4 MV model that was employed to test the abilitymore » to run an accelerator in the MR environment. An MR-compatible diode detector array was used to measure the beam profiles with the accelerator outside and inside the MR field and with the gradient coils on and off to examine if there was any effect on the delivered dose distribution. The beam profiles and time characteristics of the beam were measured. Results: The beam profiles exhibited characteristic unflattened Bremsstrahlung features with less than ±1.5% differences in the profile magnitude when the system was outside and inside the magnet and less than 1% differences with the gradient coils on and off. The central axis dose rate fluctuated by less than 1% over a 30 second period when outside and inside the MRI. Conclusion: A linaccompatible MR design has been shown to be effective in not perturbing the operation of a commercial linear accelerator. While the accelerator used in the tests was 4MV, there is nothing fundamentally different with the operation of a 6MV unit, implying that the design will enable operation of the proposed clinical unit. Research funding provided by ViewRay, Inc.« less

Power Transmission From The ITER Model Negative Ion Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boilson, D.; Esch, H. P. L. de; Grand, C.

2007-08-10

In Cadarache development on negative ion sources is being carried out on the KAMABOKO III ion source on the MANTIS test bed. This is a model of the ion source designed for the neutral beam injectors of ITER. This ion source has been developed in collaboration with JAERI, Japan, who also designed and supplied the ion source. Its target performance is to accelerate a D- beam, with a current density of 200 A/m2 and <1 electron extracted per accelerated D- ion, at a source filling pressure of 0.3 Pa. For ITER a continuous ion beam must be assured for pulsemore » lengths of 1000 s, but beams of up to 3,600 s are also envisaged. The ion source is attached to a 3 grid 30 keV accelerator (also supplied by JAERI) and the accelerated negative ion current is determined from the energy deposited on a calorimeter. During long pulse operation ({<=}1000 s) it was found that the current density of both D- and H- beams, measured at the calorimeter was lower than expected and that a large discrepancy existed between the accelerated currents measured electrically and those transmitted to the calorimeter. The possibility that this discrepancy arose because the accelerated current included electrons (which would not be able to reach the calorimeter) was investigated and subsequently eliminated. Further studies have shown that the fraction of the electrical current reaching the calorimeter varies with the pulse length, which led to the suggestion that one or more of the accelerator grids were distorting due to the incident power during operation, leading to a progressive deterioration in the beam quality.. New extraction and acceleration grids have been designed and installed, which should have a better tolerance to thermal loads than those previously used. This paper describes the measurements of the power transmission and distribution using these grids.« less

Photon spectral characteristics of dissimilar 6 MV linear accelerators.

PubMed

Hinson, William H; Kearns, William T; deGuzman, Allan F; Bourland, J Daniel

2008-05-01

This work measures and compares the energy spectra of four dosimetrically matched 6 MV beams, generated from four physically different linear accelerators. The goal of this work is twofold. First, this study determines whether the spectra of dosimetrically matched beams are measurably different. This study also demonstrates that the spectra of clinical photon beams can be measured as a part of the beam data collection process for input to a three-dimensional (3D) treatment planning system. The spectra of 6 MV beams that are dosimetrically matched for clinical use were studied to determine if the beam spectra are similarly matched. Each of the four accelerators examined had a standing waveguide, but with different physical designs. The four accelerators were two Varian 2100C/Ds (one 6 MV/18 MV waveguide and one 6 MV/10 MV waveguide), one Varian 600 C with a vertically mounted waveguide and no bending magnet, and one Siemens MD 6740 with a 6 MV/10 MV waveguide. All four accelerators had percent depth dose curves for the 6 MV beam that were matched within 1.3%. Beam spectra were determined from narrow beam transmission measurements through successive thicknesses of pure aluminum along the central axis of the accelerator, made with a graphite Farmer ion chamber with a Lucite buildup cap. An iterative nonlinear fit using a Marquardt algorithm was used to find each spectrum. Reconstructed spectra show that all four beams have similar energy distributions with only subtle differences, despite the differences in accelerator design. The measured spectra of different 6 MV beams are similar regardless of accelerator design. The measured spectra show excellent agreement with those found by the auto-modeling algorithm in a commercial 3D treatment planning system that uses a convolution dose calculation algorithm. Thus, beam spectra can be acquired in a clinical setting at the time of commissioning as a part of the routine beam data collection.

Denoising Sparse Images from GRAPPA using the Nullspace Method (DESIGN)

PubMed Central

Weller, Daniel S.; Polimeni, Jonathan R.; Grady, Leo; Wald, Lawrence L.; Adalsteinsson, Elfar; Goyal, Vivek K

2011-01-01

To accelerate magnetic resonance imaging using uniformly undersampled (nonrandom) parallel imaging beyond what is achievable with GRAPPA alone, the Denoising of Sparse Images from GRAPPA using the Nullspace method (DESIGN) is developed. The trade-off between denoising and smoothing the GRAPPA solution is studied for different levels of acceleration. Several brain images reconstructed from uniformly undersampled k-space data using DESIGN are compared against reconstructions using existing methods in terms of difference images (a qualitative measure), PSNR, and noise amplification (g-factors) as measured using the pseudo-multiple replica method. Effects of smoothing, including contrast loss, are studied in synthetic phantom data. In the experiments presented, the contrast loss and spatial resolution are competitive with existing methods. Results for several brain images demonstrate significant improvements over GRAPPA at high acceleration factors in denoising performance with limited blurring or smoothing artifacts. In addition, the measured g-factors suggest that DESIGN mitigates noise amplification better than both GRAPPA and L1 SPIR-iT (the latter limited here by uniform undersampling). PMID:22213069

Development of Maximum Considered Earthquake Ground Motion Maps

USGS Publications Warehouse

Leyendecker, E.V.; Hunt, R.J.; Frankel, A.D.; Rukstales, K.S.

2000-01-01

The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings use a design procedure that is based on spectral response acceleration rather than the traditional peak ground acceleration, peak ground velocity, or zone factors. The spectral response accelerations are obtained from maps prepared following the recommendations of the Building Seismic Safety Council's (BSSC) Seismic Design Procedures Group (SDPG). The SDPG-recommended maps, the Maximum Considered Earthquake (MCE) Ground Motion Maps, are based on the U.S. Geological Survey (USGS) probabilistic hazard maps with additional modifications incorporating deterministic ground motions in selected areas and the application of engineering judgement. The MCE ground motion maps included with the 1997 NEHRP Provisions also serve as the basis for the ground motion maps used in the seismic design portions of the 2000 International Building Code and the 2000 International Residential Code. Additionally the design maps prepared for the 1997 NEHRP Provisions, combined with selected USGS probabilistic maps, are used with the 1997 NEHRP Guidelines for the Seismic Rehabilitation of Buildings.

Superconducting Magnets for Accelerators

NASA Astrophysics Data System (ADS)

Brianti, G.; Tortschanoff, T.

1993-03-01

This chapter describes the main features of superconducting magnets for high energy synchrotrons and colliders. It refers to magnets presently used and under development for the most advanced accelerators projects, both recently constructed or in the preparatory phase. These magnets, using the technology mainly based on the NbTi conductor, are described from the aspect of design, materials, construction and performance. The trend toward higher performance can be gauged from the doubling of design field in less than a decade from about 4 T for the Tevatron to 10 T for the LHC. Special properties of the superconducting accelerator magnets, such as their general layout and the need of extensive computational treatment, the limits of performance inherent to the available conductors, the requirements on the structural design are described. The contribution is completed by elaborating on persistent current effects, quench protection and the cryostat design. As examples the main magnets for HERA and SSC, as well as the twin-aperture magnets for LHC, are presented.

Investigating the origins of the Irregular satellites using Cladistics

NASA Astrophysics Data System (ADS)

Holt, Timothy; Horner, Jonti; Tylor, Christopher; Nesvorny, David; Brown, Adrian; Carter, Brad

2017-10-01

The irregular satellites of Jupiter and Saturn are thought to be objects captured during a period of instability in the early solar system. However, the precise origins of these small bodies remain elusive. We use cladistics, a technique traditionally used by biologists, to help constrain the origins of these bodies. Our research contributes to a growing body of work that uses cladistics in astronomy, collectively called astrocladistics. We present one of the first instances of cladistics being used in a planetary science context. The analysis uses physical and compositional characteristics of three prograde Jovian irregular satellites (Themisto, Leda & Himalia), five retrograde Jovian irregular satellites (Ananke, Carme, Pasiphae, Sinope & Callirrhoe), along with Phoebe, a retrograde irregular satellite of Saturn, and several other regular Jovian and Saturnian satellites. Each of these members are representatives of their respective taxonomic groups. The irregular satellites are compared with other well-studied solar system bodies, including satellites, terrestrial planets, main belt asteroids, comets, and minor planets. We find that the Jovian irregular satellites cluster with asteroids and Ceres. The Saturnian satellites studied here are found to form an association with the comets, adding to the narrative of exchange between the outer solar system and Saturnian orbital space. Both of these results demonstrate the utility of cladistics as an analysis tool for the planetary sciences.

Effect of LED light stimulation on sleep latency in night shift people

NASA Astrophysics Data System (ADS)

Wu, Jih-Huah; Chang, Yang-Chyuan; Chiu, Hui-Ling; Fang, Wei; Shan, Yi-Chia; Chen, Ming-Jie; Chang, Yu-Ting

2014-05-01

Sleep problems are getting worse and worse in modern world. They have a severe impact on psychological and physical health, as well as social performances. From our previous study, the brainwave α rhythm, θ wave and β wave were affected by radiating the palm of the subjects with low-level laser array. In addition, from other study, the LED array stimulator (LEDAS) also has the similar effects. In the present study, LED light was used to radiate the left palm of the subjects too, and the effects were assessed with the multiple sleep latency test (MSLT) and heart-rate variability (HRV) analysis. The results revealed that it doesn't have significant meaning between these two groups. However, the tendency of the sleep latency (SL) in the LED group was shorter than that in the control group. In addition, the autonomic nervous system (ANS) analysis showed that the sympathetic nervous system was getting larger in the LED group than that in the control group, and total ANS activity were mainly getting larger in the LED group. We infer that this LED stimulation could reduce SL and balance ANS activity of the night-shift people. In the future, the further study will be conducted on normal subjects.

A galactic cloak for an exploding star

NASA Image and Video Library

2015-02-23

The galaxy pictured here is NGC 4424, located in the constellation of  Virgo. It is not visible with the naked eye but has been captured here with the NASA/ESA Hubble Space Telescope. Although it may not be obvious from this image, NGC 4424 is in fact a spiral galaxy. In this image it is seen more or less edge on, but from above you would be able to see the arms of the galaxy wrapping around its centre to give the characteristic spiral form . In 2012 astronomers observed a supernova in NGC 4424 — a violent explosion marking the end of a star’s life. During a supernova explosion, a single star can often outshine an entire galaxy. However, the supernova in NGC 4424, dubbed SN 2012cg, cannot be seen here as the image was taken ten years prior to the explosion. Along the central region of the galaxy, clouds of dust block the light from distant stars and create dark patches. To the left of NGC 4424 there are two bright objects in the frame. The brightest is another, smaller galaxy known as LEDA 213994 and the object closer to NGC 4424 is an anonymous star in our Milky Way. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Gilles Chapdelaine.

A human factors approach to snowsport safety: Novel research on pediatric participants' behaviors and head injury risk.

PubMed

Dickson, Tracey J; Trathen, Stephen; Waddington, Gordon; Terwiel, F Anne; Baltis, Daniel

2016-03-01

This study applied a human factors approach to snowsport resort systems to contribute to the understanding of the incidence and severity of pediatric snowsport head accelerations. Previous research indicates low magnitude head accelerations are common among snowsport participants. This study adds to the knowledge of snowsport safety by measuring aspects of participants' snowsport behavior and linking this with head acceleration data. School-aged students (n = 107) wore telemetry-fitted helmets and Global Positioning System (GPS) devices during snowsport activity. Data was collected over 159 sessions (total hours 701). Head accelerations recorded by the telemetry units were compared with GPS-generated data. This study found speeds attained normally exceed the testing rating for which helmets are designed; lower rates of head accelerations compared to earlier studies and that when head accelerations did occur they were generally below the threshold for concussions. Pediatric snowsport head accelerations are rare and are generally of low magnitude. Those most at risk of a head acceleration >40 g were male snowboarders. Given the recorded speeds in first time participants, increased targeting of novice snowsport participants to encourage education about the use of protective equipment, including helmets, is warranted. Post event recall was not a good indicator of having experienced a head impact. Consideration should be given to raising the standard design speed testing for snowsport helmet protective devices to reflect actual snowsport behaviors. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Accelerated testing for studying pavement design and performance (FY 2004) : research summary.

DOT National Transportation Integrated Search

2009-03-01

The thirteenth full-scale Accelerated Pavement Test (APT) experiment at the Civil Infrastructure Laboratory (CISL) of Kansas State University aimed to determine the response and the failure mode of thin concrete overlays.

Acceleration ramps along high operating speed roadways.

DOT National Transportation Integrated Search

2010-11-01

Until recently, guidelines for the geometric design of acceleration lanes used for the : successful merge of an entering vehicle into a high-speed surface transportation system : through-traffic lane have been based upon concepts and vehicle characte...

An integrated theoretical-experimental approach to accelerate translational tissue engineering.

PubMed

Coy, Rachel H; Evans, Owen R; Phillips, James B; Shipley, Rebecca J

2018-01-01

Implantable devices utilizing bioengineered tissue are increasingly showing promise as viable clinical solutions. The design of bioengineered constructs is currently directed according to the results of experiments that are used to test a wide range of different combinations and spatial arrangements of biomaterials, cells and chemical factors. There is an outstanding need to accelerate the design process and reduce financial costs, whilst minimizing the required number of animal-based experiments. These aims could be achieved through the incorporation of mathematical modelling as a preliminary design tool. Here we focus on tissue-engineered constructs for peripheral nerve repair, which are designed to aid nerve and blood vessel growth and repair after peripheral nerve injury. We offer insight into the role that mathematical modelling can play within tissue engineering, and motivate the use of modelling as a tool capable of improving and accelerating the design of nerve repair constructs in particular. Specific case studies are presented in order to illustrate the potential of mathematical modelling to direct construct design. Copyright © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd. Copyright © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.

Conceptual Design of a 50--100 MW Electron Beam Accelerator System for the National Hypersonic Wind Tunnel Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

SCHNEIDER,LARRY X.

2000-06-01

The National Hypersonic Wind Tunnel program requires an unprecedented electron beam source capable of 1--2 MeV at a beam power level of 50--100 MW. Direct-current electron accelerator technology can readily generate high average power beams to approximately 5 MeV at output efficiencies greater than 90%. However, due to the nature of research and industrial applications, there has never been a requirement for a single module with an output power exceeding approximately 500 kW. Although a 50--100 MW module is a two-order extrapolation from demonstrated power levels, the scaling of accelerator components appears reasonable. This paper presents an evaluation of componentmore » and system issues involved in the design of a 50--100 MW electron beam accelerator system with precision beam transport into a high pressure flowing air environment.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Alex

We summarize the current state of a concept for muon acceleration aimed at a future Neutrino Factory and extendable to Higgs Factory. The main thrust of these studies was to reduce the overall cost while maintaining performance by exploring the interplay between the complexity of the cooling systems and the acceptance of the accelerator complex. To ensure adequate survival for the short-lived muons, acceleration must occur at high average gradient. The need for large transverse and longitudinal acceptances drives the design of the acceleration system to an initially low RF frequency, e.g., 325 MHz, which is then increased to 650more » MHz as the transverse size shrinks with increasing energy. High-gradient normal conducting RF cavities at these frequencies require extremely high peak-power RF sources. Hence superconducting RF (SRF) cavities are chosen. We consider an SRF-efficient design based on a multi-pass (4.5) ?dogbone? RLA, extendable to multi-pass FFAG-like arcs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gündoğan, M. Tural, E-mail: mugetural@yahoo.com; Yavaş, Ö., E-mail: yavas@ankara.edu.tr; Kaya, Ç., E-mail: c.kaya@ankara.edu.tr

Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC). TARLA is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The TARLA facility is expected to provide two modes, Continuous wave (CW) and pulsed mode. Longitudinal electron bunch length will be changed between 1 and 10 ps. The bunch charge will be limited by 77pC.more » The design of the Button-type Beam Position Monitor for TARLA IR FEL is studied to operate in 1.3 GHz. Mechanical antenna design and simulations are completed considering electron beam parameters of TARLA. Ansoft HFSS and CST Particle Studio is used to compare with results of simulations.« less

Study of the Insulating Magnetic Field in an Accelerating Ion Diode

NASA Astrophysics Data System (ADS)

Kozlovsky, K. I.; Martynenko, A. S.; Vovchenko, E. D.; Lisovsky, M. I.; Isaev, A. A.

2017-12-01

The results of examination of the insulating magnetic field in an accelerating ion diode are presented. This field is produced in order to suppress the electron current and thus enhance the neutron yield of the D( d, n)3He nuclear reaction. The following two designs are discussed: a gas-filled diode with inertial electrostatic confinement of ions and a vacuum diode with a laser-plasma ion source and pulsed magnetic insulation. Although the insulating field of permanent magnets is highly nonuniform, it made it possible to extend the range of accelerating voltages to U = 200 kV and raise the neutron yield to Q = 107 in the first design. The nonuniform field structure is less prominent in the device with pulsed magnetic insulation, which demonstrated efficient deuteron acceleration with currents up to 1 kA at U = 400 kV. The predicted neutron yield is as high as 109 neutrons/pulse.

Mercury BLASTP: Accelerating Protein Sequence Alignment

PubMed Central

Jacob, Arpith; Lancaster, Joseph; Buhler, Jeremy; Harris, Brandon; Chamberlain, Roger D.

2008-01-01

Large-scale protein sequence comparison is an important but compute-intensive task in molecular biology. BLASTP is the most popular tool for comparative analysis of protein sequences. In recent years, an exponential increase in the size of protein sequence databases has required either exponentially more running time or a cluster of machines to keep pace. To address this problem, we have designed and built a high-performance FPGA-accelerated version of BLASTP, Mercury BLASTP. In this paper, we describe the architecture of the portions of the application that are accelerated in the FPGA, and we also describe the integration of these FPGA-accelerated portions with the existing BLASTP software. We have implemented Mercury BLASTP on a commodity workstation with two Xilinx Virtex-II 6000 FPGAs. We show that the new design runs 11-15 times faster than software BLASTP on a modern CPU while delivering close to 99% identical results. PMID:19492068

The status and road map of Turkish Accelerator Center (TAC)

NASA Astrophysics Data System (ADS)

Yavaş, Ö.

2012-02-01

Turkish Accelerator Center (TAC) project is supported by the State Planning Organization (SPO) of Turkey and coordinated by Ankara University. After having completed the Feasibility Report (FR) in 2000 and the Conceptual Design Report (CDR) in 2005, third phase of the project started in 2006 as an inter-universities project including ten Turkish Universities with the support of SPO. Third phase of the project has two main scientific goals: to prepare the Technical Design Report (TDR) of TAC and to establish an Infrared Free Electron Laser (IR FEL) facility, named as Turkish Accelerator and Radiation Laboratory at Ankara (TARLA) as a first step. The facility is planned to be completed in 2015 and will be based on 15-40 MeV superconducting linac. In this paper, main aims, national and regional importance, main parts main parameters, status and road map of Turkish Accelerator Center will be presented.

RF cavity design and qualification for proton accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teotia, Vikas; Malhotra, Sanjay; Ukarde, Priti

Alvarez type Drift Tube Linac (DTL) is used for acceleration of proton beam in low energy section of beta ranging from 0.04 to 0.40. DTL is cylindrical RF cavity resonating in TM010 mode at 352.21 MHz frequency. It consists of array of drift tubes arranged ensuring that DTL centre and Drift Tube centre are concentric. The Drift Tubes also houses Permanent Magnet Quadrupole for transverse focusing of proton beam. A twelve cell prototype of DTL section is designed, developed and fabricated at Bhabha Atomic Research Centre, Trombay. Complete DTL accelerator consists of eight such DTL sections. High frequency microwave simulationsmore » are carried out in SOPRANO, vector fields and COMSOL simulation software. This prototype DTL is 1640.56 mm long cavity with 520 mm ID, 600 mm OD and consists of eleven Drift Tubes, two RF end flanges, three slug tuners, six post couplers, three RF field monitors, one RF waveguide coupler, two DN100 vacuum flanges and DTL tank platform with alignment features. Girder based Drift tube mounting arrangement utilizing uncompressing energy of disc springs for optimum combo RF-vacuum seal compression is worked out and implemented. This paper discusses design of this RF vacuum cavity operating at high accelerating field gradient in ultra-high vacuum. Detailed vacuum design and results of RF and vacuum qualifications are discussed. Results on mechanical accuracy achieved on scaled pre-prototype are also presented. Paper summarizes the engineering developments carried out for this RF cavity and brings out the future activities proposed in indigenous development of high gradient RF cavities for ion accelerators. (author)« less

Multi-beam linear accelerator EVT

NASA Astrophysics Data System (ADS)

Teryaev, Vladimir E.; Kazakov, Sergey Yu.; Hirshfield, Jay L.

2016-09-01

A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initial specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. A relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.

Multi-beam linear accelerator EVT

DOE PAGES

Teryaev, Vladimir E.; Kazakov, Sergey Yu.; Hirshfield, Jay L.

2016-03-29

A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initialmore » specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. Furthermore, a relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.« less

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.

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…

The perfectly ideal accelerometer

NASA Technical Reports Server (NTRS)

Stuhlinger, Ernst

1990-01-01

Given here is a condensed version of the results and conclusions that developed during the Workshop. Upper limits of residual accelerations that can be tolerated during materials processes, presented as acceptable and as desirable limits, are shown. Designs and capabilities of various accelerometers, and their inherent problems, are compared. Results of acceleration measurements on Spacelab flights are summarized, and expected acceleration levels on the Space Station under various conditions are estimated.

HIMAC RF system with a digital synthesizer

NASA Astrophysics Data System (ADS)

Kanazawa, M.; Sato, K.; Itano, A.; Sudou, M.; Noda, K.; Takada, E.; Kumada, M.; Yamazaki, C.; Yamagishi, T.; Morii, Y.; Toyoda, E.; Tsuzuki, N.; Yagi, T.

2000-04-01

An RF acceleration system, in which digital control with a direct digital synthesizer (DDS) is applied, has been developed for the Heavy Ion Medical Accelerator in Chiba (HIMAC) synchrotron. This digital system allows us to obtain stable operation of the acceleration system over a wide frequency range from 1.04 to 7.9 MHz. In this paper the designed digital RF control system and its performance are described.

Testing of a Loop Heat Pipe Subjected to Variable Accelerating Forces

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Kaya, Tarik; Rogers, Paul; Hoff, Craig

2000-01-01

This paper presents viewgraphs of the functionality of a loop heat pipe that was subjected to variable accelerating forces. The topics include: 1) Summary of LHP (Loop Heat Pipe) Design Parameters; 2) Picture of the LHP; 3) Schematic of Test Setup; 4) Test Configurations; 5) Test Profiles; 6) Overview of Test Results; 7) Start-up; 8) Typical Start-up without Temperature Overshoot; 9) Start-up with a Large Temperature Overshoot; 10) LHP Operation Under Stationary Condition; 11) LHP Operation Under Continuous Acceleration; 12) LHP Operation Under Periodic Acceleration; 13) Effects of Acceleration on Temperature Oscillation and Hysteresis; 14) Temperature Oscillation/Hysteresis vs Spin Rate; and 15) Summary.

Configuration management and automatic control of an augmentor wing aircraft with vectored thrust

NASA Technical Reports Server (NTRS)

Cicolani, L. S.; Sridhar, B.; Meyer, G.

1979-01-01

An advanced structure for automatic flight control logic for powered-lift aircraft operating in terminal areas is under investigation at Ames Research Center. This structure is based on acceleration control; acceleration commands are constructed as the sum of acceleration on the reference trajectory and a corrective feedback acceleration to regulate path tracking errors. The central element of the structure, termed a Trimmap, uses a model of the aircraft aerodynamic and engine forces to calculate the control settings required to generate the acceleration commands. This report describes the design criteria for the Trimmap and derives a Trimmap for Ames experimental augmentor wing jet STOL research aircraft.

Beam acceleration through proton radio frequency quadrupole accelerator in BARC

NASA Astrophysics Data System (ADS)

Bhagwat, P. V.; Krishnagopal, S.; Mathew, J. V.; Singh, S. K.; Jain, P.; Rao, S. V. L. S.; Pande, M.; Kumar, R.; Roychowdhury, P.; Kelwani, H.; Rama Rao, B. V.; Gupta, S. K.; Agarwal, A.; Kukreti, B. M.; Singh, P.

2016-05-01

A 3 MeV proton Radio Frequency Quadrupole (RFQ) accelerator has been designed at the Bhabha Atomic Research Centre, Mumbai, India, for the Low Energy High Intensity Proton Accelerator (LEHIPA) programme. The 352 MHz RFQ is built in 4 segments and in the first phase two segments of the LEHIPA RFQ were commissioned, accelerating a 50 keV, 1 mA pulsed proton beam from the ion source, to an energy of 1.24 MeV. The successful operation of the RFQ gave confidence in the physics understanding and technology development that have been achieved, and indicate that the road forward can now be traversed rather more quickly.

The laser accelerator-another unicorn in the garden

NASA Astrophysics Data System (ADS)

Hand, L. N.

1981-07-01

Some proposed techniques for using laser beams to accelerate charged particles was reviewed. Two specific ideas for grating type accelerating structures are discussed. Speculations are presented about how a successful laser accelerator could be used in a multipass collider; a type of machine which would have characteristics intermediate between those of synchrotrons and linear (single pass) colliders. No definite conclusions about practical structures for laser accelerators are reached, but it is suggested that a serious effort be made to design a small prototype machine. Achieving a reasonable luminosity demands that the accelerator either be a cw machine or that laser peak power requirements to be much higher than those presently available. Use of superconducting gratings requires a wavelength in the sub-millimeter range.

A new type of accelerator for charged particle cancer therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edgecock, Rob

2013-04-19

Non-scaling Fixed Field Alternating Gradient accelerators (ns-FFAGs) show great potential for the acceleration of protons and light ions for the treatment of certain cancers. They have unique features as they combine techniques from the existing types of accelerators, cyclotrons and synchrotrons, and hence look to have advantages over both for this application. However, these unique features meant that it was necessary to build one of these accelerators to show that it works and to undertake a detailed conceptual design of a medical machine. Both of these have now been done. This paper will describe the concepts of this type ofmore » accelerator, show results from the proof-of-principle machine (EMMA) and described the medical machine (PAMELA).« less

Accurate Attitude Estimation Using ARS under Conditions of Vehicle Movement Based on Disturbance Acceleration Adaptive Estimation and Correction

PubMed Central

Xing, Li; Hang, Yijun; Xiong, Zhi; Liu, Jianye; Wan, Zhong

2016-01-01

This paper describes a disturbance acceleration adaptive estimate and correction approach for an attitude reference system (ARS) so as to improve the attitude estimate precision under vehicle movement conditions. The proposed approach depends on a Kalman filter, where the attitude error, the gyroscope zero offset error and the disturbance acceleration error are estimated. By switching the filter decay coefficient of the disturbance acceleration model in different acceleration modes, the disturbance acceleration is adaptively estimated and corrected, and then the attitude estimate precision is improved. The filter was tested in three different disturbance acceleration modes (non-acceleration, vibration-acceleration and sustained-acceleration mode, respectively) by digital simulation. Moreover, the proposed approach was tested in a kinematic vehicle experiment as well. Using the designed simulations and kinematic vehicle experiments, it has been shown that the disturbance acceleration of each mode can be accurately estimated and corrected. Moreover, compared with the complementary filter, the experimental results have explicitly demonstrated the proposed approach further improves the attitude estimate precision under vehicle movement conditions. PMID:27754469

Accurate Attitude Estimation Using ARS under Conditions of Vehicle Movement Based on Disturbance Acceleration Adaptive Estimation and Correction.

PubMed

Xing, Li; Hang, Yijun; Xiong, Zhi; Liu, Jianye; Wan, Zhong

2016-10-16

This paper describes a disturbance acceleration adaptive estimate and correction approach for an attitude reference system (ARS) so as to improve the attitude estimate precision under vehicle movement conditions. The proposed approach depends on a Kalman filter, where the attitude error, the gyroscope zero offset error and the disturbance acceleration error are estimated. By switching the filter decay coefficient of the disturbance acceleration model in different acceleration modes, the disturbance acceleration is adaptively estimated and corrected, and then the attitude estimate precision is improved. The filter was tested in three different disturbance acceleration modes (non-acceleration, vibration-acceleration and sustained-acceleration mode, respectively) by digital simulation. Moreover, the proposed approach was tested in a kinematic vehicle experiment as well. Using the designed simulations and kinematic vehicle experiments, it has been shown that the disturbance acceleration of each mode can be accurately estimated and corrected. Moreover, compared with the complementary filter, the experimental results have explicitly demonstrated the proposed approach further improves the attitude estimate precision under vehicle movement conditions.

Design of experiments in medical physics: Application to the AAA beam model validation.

PubMed

Dufreneix, S; Legrand, C; Di Bartolo, C; Bremaud, M; Mesgouez, J; Tiplica, T; Autret, D

2017-09-01

The purpose of this study is to evaluate the usefulness of the design of experiments in the analysis of multiparametric problems related to the quality assurance in radiotherapy. The main motivation is to use this statistical method to optimize the quality assurance processes in the validation of beam models. Considering the Varian Eclipse system, eight parameters with several levels were selected: energy, MLC, depth, X, Y 1 and Y 2 jaw dimensions, wedge and wedge jaw. A Taguchi table was used to define 72 validation tests. Measurements were conducted in water using a CC04 on a TrueBeam STx, a TrueBeam Tx, a Trilogy and a 2300IX accelerator matched by the vendor. Dose was computed using the AAA algorithm. The same raw data was used for all accelerators during the beam modelling. The mean difference between computed and measured doses was 0.1±0.5% for all beams and all accelerators with a maximum difference of 2.4% (under the 3% tolerance level). For all beams, the measured doses were within 0.6% for all accelerators. The energy was found to be an influencing parameter but the deviations observed were smaller than 1% and not considered clinically significant. Designs of experiment can help define the optimal measurement set to validate a beam model. The proposed method can be used to identify the prognostic factors of dose accuracy. The beam models were validated for the 4 accelerators which were found dosimetrically equivalent even though the accelerator characteristics differ. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Intraoperative radiation therapy using mobile electron linear accelerators: report of AAPM Radiation Therapy Committee Task Group No. 72.

PubMed

Beddar, A Sam; Biggs, Peter J; Chang, Sha; Ezzell, Gary A; Faddegon, Bruce A; Hensley, Frank W; Mills, Michael D

2006-05-01

Intraoperative radiation therapy (IORT) has been customarily performed either in a shielded operating suite located in the operating room (OR) or in a shielded treatment room located within the Department of Radiation Oncology. In both cases, this cancer treatment modality uses stationary linear accelerators. With the development of new technology, mobile linear accelerators have recently become available for IORT. Mobility offers flexibility in treatment location and is leading to a renewed interest in IORT. These mobile accelerator units, which can be transported any day of use to almost any location within a hospital setting, are assembled in a nondedicated environment and used to deliver IORT. Numerous aspects of the design of these new units differ from that of conventional linear accelerators. The scope of this Task Group (TG-72) will focus on items that particularly apply to mobile IORT electron systems. More specifically, the charges to this Task Group are to (i) identify the key differences between stationary and mobile electron linear accelerators used for IORT, (ii) describe and recommend the implementation of an IORT program within the OR environment, (iii) present and discuss radiation protection issues and consequences of working within a nondedicated radiotherapy environment, (iv) describe and recommend the acceptance and machine commissioning of items that are specific to mobile electron linear accelerators, and (v) design and recommend an efficient quality assurance program for mobile systems.

Principles for timing at spallation neutron sources based on developments at LANSCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, R. O.; Merl, R. B.; Rose, C. R.

2001-01-01

Due to AC-power-grid frequency fluctuations, the designers for accelerator-based spallation-neutron facilities have worked to optimize the conflicting demands of accelerator and neutron chopper performance. For the first time, we are able to quantitatively access the tradeoffs between these two constraints and design or upgrade a facility to optimize total system performance using powerful new simulation techniques. We have modeled timing systems that integrate chopper controllers and chopper hardware and built new systems. Thus, at LANSCE, we now operate multiple chopper systems and the accelerator as simple slaves to a single master-timing-reference generator. Based on this experience we recommend that spallationmore » neutron sources adhere to three principles. First, timing for pulsed sources should be planned starting with extraction at a fixed phase and working backwards toward the leading edge of the beam pulse. Second, accelerator triggers and storage ring extraction commands from neutron choppers offer only marginal benefits to accelerator-based spallation sources. Third, the storage-ring RF should be phase synchronized with neutron choppers to provide extraction without the one orbit timing uncertainty.« less

SGA-WZ: A New Strapdown Airborne Gravimeter

PubMed Central

Huang, Yangming; Olesen, Arne Vestergaard; Wu, Meiping; Zhang, Kaidong

2012-01-01

Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter taking full advantage of the inertial navigation system is described with improved mechanical design, high precision time synchronization, better thermal control and optimized sensor modeling. Apart from the general usage, the Global Positioning System (GPS) after differentiation is integrated to the inertial navigation system which provides not only more precise altitude information along with the navigation aiding, but also an effective way to calculate the vehicle acceleration. Design description and test results on the performance of the gyroscopes and accelerations will be emphasized. Analysis and discussion of the airborne field test results are also given. PMID:23012545

Magnetic-Nozzle Studies for Fusion Propulsion Applications: Gigawatt Plasma Source Operation and Magnetic Nozzle Analysis

NASA Technical Reports Server (NTRS)

Gilland, James H.; Mikekkides, Ioannis; Mikellides, Pavlos; Gregorek, Gerald; Marriott, Darin

2004-01-01

This project has been a multiyear effort to assess the feasibility of a key process inherent to virtually all fusion propulsion concepts: the expansion of a fusion-grade plasma through a diverging magnetic field. Current fusion energy research touches on this process only indirectly through studies of plasma divertors designed to remove the fusion products from a reactor. This project was aimed at directly addressing propulsion system issues, without the expense of constructing a fusion reactor. Instead, the program designed, constructed, and operated a facility suitable for simulating fusion reactor grade edge plasmas, and to examine their expansion in an expanding magnetic nozzle. The approach was to create and accelerate a dense (up to l0(exp 20)/m) plasma, stagnate it in a converging magnetic field to convert kinetic energy to thermal energy, and examine the subsequent expansion of the hot (100's eV) plasma in a subsequent magnetic nozzle. Throughout the project, there has been a parallel effort between theoretical and numerical design and modelling of the experiment and the experiment itself. In particular, the MACH2 code was used to design and predict the performance of the magnetoplasmadynamic (MPD) plasma accelerator, and to design and predict the design and expected behavior for the magnetic field coils that could be added later. Progress to date includes the theoretical accelerator design and construction, development of the power and vacuum systems to accommodate the powers and mass flow rates of interest to out research, operation of the accelerator and comparison to theoretical predictions, and computational analysis of future magnetic field coils and the expected performance of an integrated source-nozzle experiment.

Thin Film Approaches to the SRF Cavity Problem: Fabrication and Characterization of Superconducting Thin Films

NASA Astrophysics Data System (ADS)

Beringer, Douglas B.

Superconducting Radio Frequency (SRF) cavities are responsible for the acceleration of charged particles to relativistic velocities in most modern linear accelerators, such as those employed at high-energy research facilities like Thomas Jefferson National Laboratory's CEBAF and the LHC at CERN. Recognizing SRF as primarily a surface phenomenon enables the possibility of applying thin films to the interior surface of SRF cavities, opening a formidable tool chest of opportunities by combining and designing materials that offer greater benefit. Thus, while improvements in radio frequency cavity design and refinements in cavity processing techniques have improved accelerator performance and efficiency - 1.5 GHz bulk niobium SRF cavities have achieved accelerating gradients in excess of 35 MV/m - there exist fundamental material bounds in bulk superconductors limiting the maximally sustained accelerating field gradient (approximately 45 MV/m for Niobium) where inevitable thermodynamic breakdown occurs. With state of the art niobium based cavity design fast approaching these theoretical limits, novel material innovations must be sought in order to realize next generation SRF cavities. One proposed method to improve SRF performance is to utilize thin film superconducting-insulating-superconducting (SIS) multilayer structures to effectively magnetically screen a bulk superconducting layer such that it can operate at higher field gradients before suffering critically detrimental SRF losses. This dissertation focuses on the production and characterization of thin film superconductors for such SIS layers for radio-frequency applications.

On the safety of ITER accelerators.

PubMed

Li, Ge

2013-01-01

Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate -1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER.

Two-material optimization of plate armour for blast mitigation using hybrid cellular automata

NASA Astrophysics Data System (ADS)

Goetz, J.; Tan, H.; Renaud, J.; Tovar, A.

2012-08-01

With the increased use of improvised explosive devices in regions at war, the threat to military and civilian life has risen. Cabin penetration and gross acceleration are the primary threats in an explosive event. Cabin penetration crushes occupants, damaging the lower body. Acceleration causes death at high magnitudes. This investigation develops a process of designing armour that simultaneously mitigates cabin penetration and acceleration. The hybrid cellular automaton (HCA) method of topology optimization has proven efficient and robust in problems involving large, plastic deformations such as crash impact. Here HCA is extended to the design of armour under blast loading. The ability to distribute two metallic phases, as opposed to one material and void, is also added. The blast wave energy transforms on impact into internal energy (IE) inside the solid medium. Maximum attenuation occurs with maximized IE. The resulting structures show HCA's potential for designing blast mitigating armour structures.

On the safety of ITER accelerators

PubMed Central

Li, Ge

2013-01-01

Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate −1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER. PMID:24008267

Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakeman, M. S.; University of Nevada Reno, Reno, NV 89557; Van Tilborg, J.

The design and current status of experiments to couple the Tapered Hybrid Undulator (THUNDER) to the Lawrence Berkeley National Laboratory (LBNL) laser plasma accelerator (LPA) to measure electron beam energy spread and emittance are presented.

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.

TU-H-BRA-01: The Physics of High Power Radiofrequency Isolation in a Novel Compact Linear Accelerator Based MRI Guided Radiation Therapy System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamb, J; Low, D; Mutic, S

Purpose: To develop a method for isolating the radiofrequency waves emanating from linear accelerator components from the magnetic resonance imaging (MRI) system of an integrated MRI-linac. Methods: An MRI-guided radiation therapy system has been designed that integrates a linear accelerator with simultaneous MR imaging. The radiofrequency waves created by the accelerating process would degrade MR image quality, so a method for containing the radiofrequency waves and isolating the MR imager from them was developed. The linear accelerator radiofrequency modulator was placed outside the room, so a filter was designed to eliminate the radiofrequency corresponding to the proton Larmour frequency ofmore » 14.7 MHz. Placing the radiofrequency emitting components in a typical Faraday cage would have reduced the radiofrequency emissions, but the design would be susceptible to small gaps in the shield due to the efficiency of the Faraday cage reflecting internal radiofrequency emissions. To reduce internal radiofrequency reflections, the Faraday cage was lined with carbon fiber sheets. Carbon fiber has the property of attenuating the radiofrequency energy so that the overall radiofrequency field inside the Faraday cage is reduced, decreasing any radiofrequency energy emitted from small gaps in the cage walls. Results: Within a 1.2 MHz band centered on the Larmor frequency, the radiofrequency (RF) leakage from the Faraday cage was measured to be −90 dB with no RF on, −40 dB with the RF on and no shield, returning to −90 dB with the RF on and shields in place. The radiofrequency filter attenuated the linear accelerator modulator emissions in the 14.7 MHz band by 70 dB. Conclusions: One of the major challenges in designing a compact linear accelerator based MRI-guided radiation therapy system, that of isolating the high power RF system from the MRI, has been solved. The measured radiofrequency emissions are sufficiently small to enable system integration. This research was funded by ViewRay, Inc., Oakwood, OH.« less

The history and future of accelerator radiological protection.

PubMed

Thomas, R H

2001-01-01

The development of accelerator radiological protection from the mid-1930s, just after the invention of the cyclotron, to the present day is described. Three major themes--physics, personalities and politics--are developed. In the sections describing physics the development of shielding design though measurement, radiation transport calculations, the impact of accelerators on the environment and dosimetry in accelerator radiation fields are described. The discussion is limited to high-energy, high-intensity electron and proton accelerators. The impact of notable personalities on the development of both the basic science and on the accelerator health physics profession itself is described. The important role played by scholars and teachers is discussed. In the final section. which discusses the future of accelerator radiological protection, some emphasis is given to the social and political aspects that must he faced in the years ahead.

Beam shaping assembly optimization for (7)Li(p,n)(7)Be accelerator based BNCT.

PubMed

Minsky, D M; Kreiner, A J

2014-06-01

Within the framework of accelerator-based BNCT, a project to develop a folded Tandem-ElectroStatic-Quadrupole accelerator is under way at the Atomic Energy Commission of Argentina. The proposed accelerator is conceived to deliver a proton beam of 30mA at about 2.5MeV. In this work we explore a Beam Shaping Assembly (BSA) design based on the (7)Li(p,n)(7)Be neutron production reaction to obtain neutron beams to treat deep seated tumors. © 2013 Elsevier Ltd. All rights reserved.

Demountable damped cavity for HOM-damping in ILC superconducting accelerating cavities

NASA Astrophysics Data System (ADS)

Konomi, T.; Yasuda, F.; Furuta, F.; Saito, K.

2014-01-01

We have designed a new higher-order-mode (HOM) damper called a demountable damped cavity (DDC) as part of the R&D efforts for the superconducting cavity of the International Linear Collider (ILC). The DDC has two design concepts. The first is an axially symmetrical layout to obtain high damping efficiency. The DDC has a coaxial structure along the beam axis to realize strong coupling with HOMs. HOMs are damped by an RF absorber at the end of the coaxial waveguide and the accelerating mode is reflected by a choke filter mounted at the entrance of the coaxial waveguide. The second design concept is a demountable structure to facilitate cleaning, in order to suppress the Q-slope problem in a high field. A single-cell cavity with the DDC was fabricated to test four performance parameters. The first was frequency matching between the accelerating cavity and the choke filter. Since the bandwidth of the resonance frequency in a superconducting cavity is very narrow, there is a possibility that the accelerating field will leak to the RF absorber because of thermal shrinkage. The design bandwidth of the choke filter is 25 kHz. It was demonstrated that frequency matching adjusted at room temperature could be successfully maintained at 2 K. The second parameter was the performance of the demountable structure. At the joint, the magnetic field is 1/6 of the maximum field in the accelerating cavity. Ultimately, the accelerating field reached 19 MV/m and Q0 was 1.5×1010 with a knife-edge shape. The third parameter was field emission and multipacting. Although the choke structure has numerous parallel surfaces that are susceptible to the multipacting problem, it was found that neither field emission nor multipacting presented problems in both an experiment and simulation. The final parameter was the Q values of the HOM. The RF absorber adopted in the system is a Ni-Zn ferrite type. The RF absorber shape was designed based on the measurement data of permittivity and permeability at 77 K. The Q values of the HOM in the DDC are 10-100 times lower than those of a TESLA-type HOM coupler.

Cryogenic distribution box for Fermi National Accelerator Laboratory

NASA Astrophysics Data System (ADS)

Svehla, M. R.; Bonnema, E. C.; Cunningham, E. K.

2017-12-01

Meyer Tool & Mfg., Inc (Meyer Tool) of Oak Lawn, Illinois is manufacturing a cryogenic distribution box for Fermi National Accelerator Laboratory (FNAL). The distribution box will be used for the Muon-to-electron conversion (Mu2e) experiment. The box includes twenty-seven cryogenic valves, two heat exchangers, a thermal shield, and an internal nitrogen separator vessel, all contained within a six-foot diameter ASME coded vacuum vessel. This paper discusses the design and manufacturing processes that were implemented to meet the unique fabrication requirements of this distribution box. Design and manufacturing features discussed include: 1) Thermal strap design and fabrication, 2) Evolution of piping connections to heat exchangers, 3) Nitrogen phase separator design, 4) ASME code design of vacuum vessel, and 5) Cryogenic valve installation.

Plasma Measurements in an Integrated-System FARAD Thruster

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Rose, M. F.; Miller, R.; Best, S.

2007-01-01

Pulsed inductive plasma accelerators are spacecraft propulsion devices in which energy is stored in a capacitor and then discharged through an inductive coil. The device is electrodeless, inducing a current sheet in a plasma located near the face of the coil. The propellant is accelerated and expelled at a high exhaust velocity (order of 10 km/s) through the interaction of the plasma current and the induced magnetic field. The Faraday Accelerator with RF-Assisted Discharge (FARAD) thruster[1,2] is a type of pulsed inductive plasma accelerator in which the plasma is preionized by a mechanism separate from that used to form the current sheet and accelerate the gas. Employing a separate preionization mechanism allows for the formation of an inductive current sheet at much lower discharge energies and voltages than those used in previous pulsed inductive accelerators like the Pulsed Inductive Thruster (PIT). A benchtop FARAD thruster was designed following guidelines and similarity performance parameters presented in Refs. [3,4]. This design is described in detail in Ref. [5]. In this paper, we present the temporally and spatially resolved measurements of the preionized plasma and inductively-accelerated current sheet in the FARAD thruster operating with a Vector Inversion Generator (VIG) to preionize the gas and a Bernardes and Merryman circuit topology to provide inductive acceleration. The acceleration stage operates on the order of 100 J/pulse. Fast-framing photography will be used to produce a time-resolved, global view of the evolving current sheet. Local diagnostics used include a fast ionization gauge capable of mapping the gas distribution prior to plasma initiation; direct measurement of the induced magnetic field using B-dot probes, induced azimuthal current measurement using a mini-Rogowski coil, and direct probing of the number density and electron temperature using triple probes.

A Novel Angular Acceleration Sensor Based on the Electromagnetic Induction Principle and Investigation of Its Calibration Tests

PubMed Central

Zhao, Hao; Feng, Hao

2013-01-01

An angular acceleration sensor can be used for the dynamic analysis of human and joint motions. In this paper, an angular acceleration sensor with novel structure based on the principle of electromagnetic induction is designed. The method involves the construction of a constant magnetic field by the excitation windings of sensor, and the cup-shaped rotor that cut the magnetic field. The output windings of the sensor generate an electromotive force, which is directly proportional to the angular acceleration through the electromagnetic coupling when the rotor has rotational angular acceleration. The mechanical structure and the magnetic working circuit of the sensor are described. The output properties and the mathematical model including the transfer function and state-space model of the sensor are established. The asymptotical stability of the sensor when it is working is verified by the Lyapunov Theorem. An angular acceleration calibration device based on the torsional pendulum principle is designed. The method involves the coaxial connection of the angular acceleration sensor, torsion pendulum and a high-precision angle sensor, and then an initial external force is applied to the torsion pendulum to produce a periodic damping angle oscillation. The angular acceleration sensor and the angle sensor will generate two corresponding electrical signals. The sensitivity coefficient of the angular acceleration sensor can be obtained after processing these two-channel signals. The experiment results show that the sensitivity coefficient of the sensor is about 17.29 mv/Krad·s2. Finally, the errors existing in the practical applications of the sensor are discussed and the corresponding improvement measures are proposed to provide effective technical support for the practical promotion of the novel sensor. PMID:23941911

Project acceleration : making the leap from pilot to commercialization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borneo, Daniel R.

2010-05-01

Since the energy storage technology market is in a relatively emergent phase, narrowing the gap between pilot project status and commercialization is fundamental to the accelerating of this innovative market space. This session will explore regional market design factors to facilitate the storage enterprise. You will also hear about: quantifying transmission and generation efficiency enhancements; resource planning for storage; and assessing market mechanisms to accelerate storage adoption regionally.

Stability condition for the drive bunch in a collinear wakefield accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baturin, S. S.; Zholents, A.

The beam breakup instability of the drive bunch in the structure-based collinear wakefield accelerator is considered and a stabilizing method is proposed. The method includes using the specially designed beam focusing channel, applying the energy chirp along the electron bunch, and keeping energy chirp constant during the drive bunch deceleration. A stability condition is derived that defines the limit on the accelerating field for the witness bunch.

Permanent magnet focused X-band photoinjector

DOEpatents

Yu, David U. L.; Rosenzweig, James

2002-09-10

A compact high energy photoelectron injector integrates the photocathode directly into a multicell linear accelerator with no drift space between the injection and the linac. High electron beam brightness is achieved by accelerating a tightly focused electron beam in an integrated, multi-cell, X-band rf linear accelerator (linac). The photoelectron linac employs a Plane-Wave-Transformer (PWT) design which provides strong cell-to-cell coupling, easing manufacturing tolerances and costs.

Evaluation of bonded concrete overlays over asphalt under accelerated loading : research project capsule.

DOT National Transportation Integrated Search

2014-05-01

The overall objective of this research study is to evaluate the structural performance and loadcarrying : capacity of bonded concrete overlay pavement structures through accelerated pavement : testing and document the experience of mix design and con...

Accelerator-based conversion (ABC) of weapons plutonium: Plant layout study and related design issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cowell, B.S.; Fontana, M.H.; Krakowski, R.A.

1995-04-01

In preparation for and in support of a detailed R and D Plan for the Accelerator-Based Conversion (ABC) of weapons plutonium, an ABC Plant Layout Study was conducted at the level of a pre-conceptual engineering design. The plant layout is based on an adaptation of the Molten-Salt Breeder Reactor (MSBR) detailed conceptual design that was completed in the early 1070s. Although the ABC Plant Layout Study included the Accelerator Equipment as an essential element, the engineering assessment focused primarily on the Target; Primary System (blanket and all systems containing plutonium-bearing fuel salt); the Heat-Removal System (secondary-coolant-salt and supercritical-steam systems); Chemicalmore » Processing; Operation and Maintenance; Containment and Safety; and Instrumentation and Control systems. Although constrained primarily to a reflection of an accelerator-driven (subcritical) variant of MSBR system, unique features and added flexibilities of the ABC suggest improved or alternative approaches to each of the above-listed subsystems; these, along with the key technical issues in need of resolution through a detailed R&D plan for ABC are described on the bases of the ``strawman`` or ``point-of-departure`` plant layout that resulted from this study.« less

Cloud-based design of high average power traveling wave linacs

NASA Astrophysics Data System (ADS)

Kutsaev, S. V.; Eidelman, Y.; Bruhwiler, D. L.; Moeller, P.; Nagler, R.; Barbe Welzel, J.

2017-12-01

The design of industrial high average power traveling wave linacs must accurately consider some specific effects. For example, acceleration of high current beam reduces power flow in the accelerating waveguide. Space charge may influence the stability of longitudinal or transverse beam dynamics. Accurate treatment of beam loading is central to the design of high-power TW accelerators, and it is especially difficult to model in the meter-scale region where the electrons are nonrelativistic. Currently, there are two types of available codes: tracking codes (e.g. PARMELA or ASTRA) that cannot solve self-consistent problems, and particle-in-cell codes (e.g. Magic 3D or CST Particle Studio) that can model the physics correctly but are very time-consuming and resource-demanding. Hellweg is a special tool for quick and accurate electron dynamics simulation in traveling wave accelerating structures. The underlying theory of this software is based on the differential equations of motion. The effects considered in this code include beam loading, space charge forces, and external magnetic fields. We present the current capabilities of the code, provide benchmarking results, and discuss future plans. We also describe the browser-based GUI for executing Hellweg in the cloud.

Conceptual design of a pulsed-power accelerator optimized for megajoule-class 1-TPa dynamic-material-physics experiments

DOE PAGES

Stygar, William A.; Reisman, David B.; Stoltzfus, Brian S.; ...

2016-07-07

In this study, we have developed a conceptual design of a next-generation pulsed-power accelerator that is optmized for driving megajoule-class dynamic-material-physics experiments at pressures as high as 1 TPa. The design is based on an accelerator architecture that is founded on three concepts: single-stage electrical-pulse compression, impedance matching, and transit-time-isolated drive circuits. Since much of the accelerator is water insulated, we refer to this machine as Neptune. The prime power source of Neptune consists of 600 independent impedance-matched Marx generators. As much as 0.8 MJ and 20 MA can be delivered in a 300-ns pulse to a 16-mΩ physics load;more » hence Neptune is a megajoule-class 20-MA arbitrary waveform generator. Neptune will allow the international scientific community to conduct dynamic equation-of-state, phase-transition, mechanical-property, and other material-physics experiments with a wide variety of well-defined drive-pressure time histories. Because Neptune can deliver on the order of a megajoule to a load, such experiments can be conducted on centimeter-scale samples at terapascal pressures with time histories as long as 1 μs.« less

On the hole accelerator for III-nitride light-emitting diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Zi-Hui, E-mail: zh.zhang@hebut.edu.cn, E-mail: wbi@hebut.edu.cn, E-mail: volkan@stanfordalumni.org, E-mail: sunxw@sustc.edu.cn; Zhang, Yonghui; Bi, Wengang, E-mail: zh.zhang@hebut.edu.cn, E-mail: wbi@hebut.edu.cn, E-mail: volkan@stanfordalumni.org, E-mail: sunxw@sustc.edu.cn

2016-04-11

In this work, we systematically conduct parametric studies revealing the sensitivity of the hole injection on the hole accelerator (a hole accelerator is made of the polarization mismatched p-electron blocking layer (EBL)/p-GaN/p-Al{sub x}Ga{sub 1−x}N heterojunction) with different designs, including the AlN composition in the p-Al{sub x}Ga{sub 1−x}N layer, and the thickness for the p-GaN layer and the p-Al{sub x}Ga{sub 1−x}N layer. According to our findings, the energy that the holes obtain does not monotonically increase as the AlN incorporation in the p-Al{sub x}Ga{sub 1−x}N layer increases. Meanwhile, with p-GaN layer or p-Al{sub x}Ga{sub 1−x}N layer thickening, the energy that themore » holes gain increases and then reaches a saturation level. Thus, the hole injection efficiency and the device efficiency are very sensitive to the p-EBL/p-GaN/p-Al{sub x}Ga{sub 1−x}N design, and the hole accelerator can effectively increase the hole injection if properly designed.« less

Controllability in Multi-Stage Laser Ion Acceleration

NASA Astrophysics Data System (ADS)

Kawata, S.; Kamiyama, D.; Ohtake, Y.; Barada, D.; Ma, Y. Y.; Kong, Q.; Wang, P. X.; Gu, Y. J.; Li, X. F.; Yu, Q.

2015-11-01

The present paper shows a concept for a future laser ion accelerator, which should have an ion source, ion collimators, ion beam bunchers and ion post acceleration devices. Based on the laser ion accelerator components, the ion particle energy and the ion energy spectrum are controlled, and a future compact laser ion accelerator would be designed for ion cancer therapy or for ion material treatment. In this study each component is designed to control the ion beam quality. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching are successfully realized by a multi-stage laser-target interaction. A combination of each component provides a high controllability of the ion beam quality to meet variable requirements in various purposes in the laser ion accelerator. The work was partly supported by MEXT, JSPS, ASHULA project/ ILE, Osaka University, CORE (Center for Optical Research and Education, Utsunomiya University, Japan), Fudan University and CDI (Creative Dept. for Innovation) in CCRD, Utsunomiya University.

Sensitivity Analysis of the Off-Normal Conditions of the SPIDER Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veltri, P.; Agostinetti, P.; Antoni, V.

2011-09-26

In the context of the development of the 1 MV neutral beam injector for the ITER tokamak, the study on beam formation and acceleration has considerable importance. This effort includes the ion source and accelerator SPIDER (Source for Production of Ions of Deuterium Extracted from an Rf plasma) ion source, planned to be built in Padova, and designed to extract and accelerate a 355 A/m{sup 2} current of H{sup -}(or 285 A/m{sup 2} D{sup -}) up to 100 kV. Exhaustive simulations were already carried out during the accelerator optimization leading to the present design. However, as it is expected thatmore » the accelerator shall operate also in case of pre-programmed or undesired off-normal conditions, the investigation of a large set of off-normal scenarios is necessary. These analyses will also be useful for the evaluation of the real performances of the machine, and should help in interpreting experimental results, or in identifying dangerous operating conditions.The present contribution offers an overview of the results obtained during the investigation of these off-normal conditions, by means of different modeling tools and codes. The results, showed a good flexibility of the device in different operating conditions. Where the consequences of the abnormalities appeared to be problematic further analysis were addressed.« less

The Effect of Acceleration Sprint and Zig-zag Drill Combination to Increase Students’ Speed and Agility

NASA Astrophysics Data System (ADS)

Bana, O.; Mintarto, E.; Kusnanik, N. W.

2018-01-01

The purpose of this research is to analyze the following factors: (1) how far the effect of exercise acceleration sprint on the speed and agility (2) how much influence the zig-zag drill combination to the speed and agility (3) and is there any difference between the effects of exercise acceleration sprint and practice zig-zag drill combination of the speed and agility. This research is quantitative with quasi-experimental approach. The design of this study is matching only design.This study was conducted on 33 male students who take part in extracurricular and divided into 3 groups with 11 students in each group. Group 1 was given training of acceleration sprint, group 2 was given zig-zag training combination drills of conventional and exercises for group 3, for 8 weeks. The data collection was using sprint 30 meter to test the speed and agility t-test to test agility. Data were analyzed using t-test and analysis of variance. The conclusion of the research is (1) there is a significant effect of exercise acceleration sprint for the speed and agility, (2) there is a significant influence combination zig-zag drills, on speed and agility (3) and exercise acceleration sprint have more effect on the speed and agility.

Coupled Mechanical-Electrochemical-Thermal Modeling for Accelerated Design of EV Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santhanagopalan, Shriram; Zhang, Chao; Kim, Gi-Heon

2015-05-03

This presentation provides an overview of the mechanical electrochemical-thermal (M-ECT) modeling efforts. The physical phenomena occurring in a battery are many and complex and operate at different scales (particle, electrodes, cell, and pack). A better understanding of the interplay between different physics occurring at different scales through modeling could provide insight to design improved batteries for electric vehicles. Work funded by the U.S. DOE has resulted in development of computer-aided engineering (CAE) tools to accelerate electrochemical and thermal design of batteries; mechanical modeling is under way. Three competitive CAE tools are now commercially available.

Conceptual Design for CLIC Gun Pulser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Tao

The Compact Linear Collider (CLIC) is a proposed future electron-positron collider, designed to perform collisions at energies from 0.5 to 5 TeV, with a nominal design optimized for 3 TeV (Dannheim, 2012). The Drive Beam Accelerator consists of a thermionic DC gun, bunching section and an accelerating section. The thermionic gun needs deliver a long (~143us) pulse of current into the buncher. A pulser is needed to drive grid of the gun to generate a stable current output. This report explores the requirements of the gun pulser and potential solutions to regulate grid current.

Calculations of the Acceleration of Centrifugal Loading on Adherent Cells

NASA Astrophysics Data System (ADS)

Chen, Kang; Song, Yang; Liu, Qing; Zhang, Chunqiu

2017-07-01

Studies have shown that the morphology and function of living cells are greatly affected by the state of different high acceleration. Based on the centrifuge, we designed a centrifugal cell loading machine for the mechanical biology of cells under high acceleration loading. For the machine, the feasibility of the experiment was studied by means of constant acceleration or variable acceleration loading in the Petri dish fixture and/or culture flask. Here we analyzed the distribution of the acceleration of the cells with the change of position and size of the culturing device quantitatively. It is obtained that Petri dish fixture and/or culture flask can be used for constant acceleration loading by experiments; the centripetal acceleration of the adherent cells increases with the increase of the distance between the rotor center of the centrifuge and the fixture of the Petri dish and the size of the fixture. It achieves the idea that the general biology laboratory can conduct the study of mechanical biology at high acceleration. It also provides a basis for more accurate study of the law of high acceleration on mechanobiology of cells.

Design of a ram accelerator mass launch system

NASA Technical Reports Server (NTRS)

Aarnio, Michael; Armerding, Calvin; Berschauer, Andrew; Christofferson, Erik; Clement, Paul; Gohd, Robin; Neely, Bret; Reed, David; Rodriguez, Carlos; Swanstrom, Fredrick

1988-01-01

The ram accelerator mass launch system has been proposed to greatly reduce the costs of placing acceleration-insensitive payloads into low earth orbit. The ram accelerator is a chemically propelled, impulsive mass launch system capable of efficiently accelerating relatively large masses from velocities of 0.7 km/sec to 10 km/sec. The principles of propulsion are based on those of a conventional supersonic air-breathing ramjet; however the device operates in a somewhat different manner. The payload carrying vehicle resembles the center-body of the ramjet and accelerates through a stationary tube which acts as the outer cowling. The tube is filled with premixed gaseous fuel and oxidizer mixtures that burn in the vicinity of the vehicle's base, producing a thrust which accelerates the vehicle through the tube. This study examines the requirement for placing a 2000 kg vehicle into a 500 km circular orbit with a minimum amount of on-board rocket propellant for orbital maneuvers. The goal is to achieve a 50 pct payload mass fraction. The proposed design requirements have several self-imposed constraints that define the vehicle and tube configurations. Structural considerations on the vehicle and tube wall dictate an upper acceleration limit of 1000 g's and a tube inside diameter of 1.0 m. In-tube propulsive requirements and vehicle structural constraints result in a vehicle diameter of 0.76 m, a total length of 7.5 m and a nose-cone half angle of 7 degrees. An ablating nose-cone constructed from carbon-carbon composite serves as the thermal protection mechanism for atmospheric transit.

Advances in Nonlinear Non-Scaling FFAGs

NASA Astrophysics Data System (ADS)

Johnstone, C.; Berz, M.; Makino, K.; Koscielniak, S.; Snopok, P.

Accelerators are playing increasingly important roles in basic science, technology, and medicine. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon Collider) but remain particularly challenging, encountering duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton driver is not presently considered technically achievable with conventional re-circulating accelerators. One, as-yet, unexplored re-circulating accelerator, the Fixed-field Alternating Gradient or FFAG, is an attractive alternative to the other approaches to a high-power beam source. Its strong focusing optics can mitigate space charge effects and achieve higher bunch charges than are possible in a cyclotron, and a recent innovation in design has coupled stable tunes with isochronous orbits, making the FFAG capable of fixed-frequency, CW acceleration, as in the classical cyclotron but beyond their energy reach, well into the relativistic regime. This new concept has been advanced in non-scaling nonlinear FFAGs using powerful new methodologies developed for FFAG accelerator design and simulation. The machine described here has the high average current advantage and duty cycle of the cyclotron (without using broadband RF frequencies) in combination with the strong focusing, smaller losses, and energy variability that are more typical of the synchrotron. The current industrial and medical standard is a cyclotron, but a competing CW FFAG could promote a shift in this baseline. This paper reports on these new advances in FFAG accelerator technology and presents advanced modeling tools for fixed-field accelerators unique to the code COSY INFINITY.1

Failure Engineering Study and Accelerated Stress Test Results for the Mars Global Surveyor Spacecraft's Power Shunt Assemblies

NASA Technical Reports Server (NTRS)

Gibbel, Mark; Larson, Timothy

2000-01-01

An Engineering-of-Failure approach to designing and executing an accelerated product qualification test was performed to support a risk assessment of a "work-around" necessitated by an on-orbit failure of another piece of hardware on the Mars Global Surveyor spacecraft. The proposed work-around involved exceeding the previous qualification experience both in terms of extreme cold exposure level and in terms of demonstrated low cycle fatigue life for the power shunt assemblies. An analysis was performed to identify potential failure sites, modes and associated failure mechanisms consistent with the new use conditions. A test was then designed and executed which accelerated the failure mechanisms identified by analysis. Verification of the resulting failure mechanism concluded the effort.

Electron Lens Construction for the Integrable Optics Test Accelerator at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGee, Mike; Carlson, Kermit; Nobrega, Lucy

The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. Construction of an electron lens for IOTA is necessary for both electron and proton operation. Components required for the Electron Lens design include; a 0.8 T conventional water-cooled main solenoid, and magnetic bending and focusing elements. The foundation of the design relies on repurposing the Fermilab Tevatron Electron Lens II (TELII)more » gun and collector under ultra-high vacuum (UHV) conditions.« less

Study and development of CW room temperature rebuncher for SARAF accelerator

NASA Astrophysics Data System (ADS)

Kaizer, B.; Rodnizki, J.; Farber, E.; Perry, A.; Danon, L.; Horvitz, Z.; Mazor, O.; Friedman, A.; Di Giacomo, M.; Leyge, J.-F.; Michel, M.; Toussaint, P.

2017-11-01

The SARAF 176 MHz accelerator is designed to provide CW proton/deuteron beams up to 5 mA current and 40 MeV accelerated ion energy. Phase I of SARAF (up to 4-5 MeV) has been installed, commissioned, and is available for experimental work. Phase II of SARAF is currently in the design and first prototyping stage and will contain longer MEBT with three rebunchers and four cryomodules, each consisting of SC HWRs and solenoids. Phase II MEBT line is designed to follow a 1.3 MeV/u RFQ, is 4.5 m long, and contains three 176 MHz rebunchers providing a field integral of 105 kV. Different rebuncher configurations have been studied in order to minimize the RF losses and maximize the shunt impedance. Different apertures have also been tested with the 40 mm diameter required by beam dynamics. The simulations were done using CST Microwave Studio. CEA leads the design for SARAF phase II linac including the MEBT rebunchers and has studied a mixed solid copper and Cu plated stainless steel, 3-gap cavity. SNRC is developing a 4-gap OFHC copper rebuncher as a risk reduction. Both designs are presented and discussed in the paper.

Design, characterization, and control of the NASA three degree of freedom reaction compensation platform

NASA Technical Reports Server (NTRS)

Birkhimer, Craig; Newman, Wyatt; Choi, Benjamin; Lawrence, Charles

1994-01-01

Increasing research is being done into industrial uses for the microgravity environment aboard orbiting space vehicles. However, there is some concern over the effects of reaction forces produced by moving objects, especially motors, robotic actuators, and astronauts. Reaction forces produced by the movement of these objects may manifest themselves as undesirable accelerations in the space vehicle making the vehicle unusable for microgravity applications. It is desirable to provide compensation for such forces using active means. This paper presents the design and experimental evaluation of the NASA three degree of freedom reaction compensation platform, a system designed to be a testbed for the feasibility of active attenuation of reaction forces caused by moving objects in a microgravity environment. Unique 'linear motors,' which convert electrical current directly into rectilinear force, are used in the platform design. The linear motors induce accelerations of the displacer inertias. These accelerations create reaction forces that may be controlled to counteract disturbance forces introduced to the platform. The stated project goal is to reduce reaction forces by 90 percent, or -20 dB. Description of the system hardware, characterization of the actuators and the composite system, and design of the software safety system and control software are included.

Magnetic Materials Characterization and Modeling for the Enhanced Design of Magnetic Shielding of Cryomodules in Particle Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sah, Sanjay

Particle accelerators produce beams of high-energy particles, which are used for both fundamental and applied scientific research and are critical to the development of accelerator driven sub-critical reactor systems. An effective magnetic shield is very important to achieve higher quality factor (Qo) of the cryomodule of a particle accelerator. The allowed value of field inside the cavity due to all external fields (particularly the Earth’s magnetic field) is ~15 mG or less. The goal of this PhD dissertation is to comprehensively study the magnetic properties of commonly used magnetic shielding materials at both cryogenic and room temperatures. This knowledge canmore » be used for the enhanced design of magnetic shields of cryomodes (CM) in particle accelerators. To this end, we first studied the temperature dependent magnetization behavior (M-H curves) of Amumetal and A4K under different annealing and deformation conditions. This characterized the effect of stress or deformation induced during the manufacturing processes and subsequent restoration of high permeability with appropriate heat treatment. Next, an energy based stochastic model for temperature dependent anhysteretic magnetization behavior of ferromagnetic materials was proposed and benchmarked against experimental data. We show that this model is able to simulate and explain the magnetic behavior of as rolled, deformed and annealed amumetal and A4K over a large range of temperatures. The experimental results for permeability are then used in a finite element model (FEM) in COMSOL to evaluate the shielding effectiveness of multiple shield designs at room temperature as well as cryogenic temperature. This work could serve as a guideline for future design, development and fabrication of magnetic shields of CMs.« less

Using a national archive of patient experience narratives to promote local patient-centered quality improvement: an ethnographic process evaluation of 'accelerated' experience-based co-design.

PubMed

Locock, Louise; Robert, Glenn; Boaz, Annette; Vougioukalou, Sonia; Shuldham, Caroline; Fielden, Jonathan; Ziebland, Sue; Gager, Melanie; Tollyfield, Ruth; Pearcey, John

2014-10-01

To evaluate an accelerated form of experience-based co-design (EBCD), a type of participatory action research in which patients and staff work together to improve quality; to observe how acceleration affected the process and outcomes of the intervention. An ethnographic process evaluation of an adapted form of EBCD was conducted, including observations, interviews, questionnaires and documentary analysis. Whilst retaining all components of EBCD, the adapted approach replaced local patient interviews with secondary analysis of a national archive of patient experience narratives to create national trigger films; shortened the timeframe; and employed local improvement facilitators. It was tested in intensive care and lung cancer in two English National Health Service (NHS) hospitals. A total of 96 clinical staff (primarily nursing and medical), and 63 patients and family members participated in co-design activities. The accelerated approach proved acceptable to staff and patients; using films of national rather than local narratives did not adversely affect local NHS staff engagement, and may have made the process less threatening or challenging. Local patients felt the national films generally reflected important themes although a minority felt they were more negative than their own experience. However, they served their purpose of 'triggering' discussion between patients and staff, and the resulting 48 co-design (improvement) activities across the four pathways were similar to those in EBCD, but achieved more quickly and at lower cost. Accelerated EBCD offers a rigorous and relatively cost-effective patient-centered quality improvement approach. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Overview of graduate training program of John Adams Institute for Accelerator Science

NASA Astrophysics Data System (ADS)

Seryi, Andrei

The John Adams Institute for Accelerator Science is a center of excellence in the UK for advanced and novel accelerator technology, providing expertise, research, development and training in accelerator techniques, and promoting advanced accelerator applications in science and society. We work in JAI on design of novel light sources upgrades of 3-rd generation and novel FELs, on plasma acceleration and its application to industrial and medical fields, on novel energy recovery compact linacs and advanced beam diagnostics, and many other projects. The JAI is based on three universities - University of Oxford, Imperial College London and Royal Holloway University of London. Every year 6 to 10 accelerators science experts, trained via research on cutting edge projects, defend their PhD thesis in JAI partner universities. In this presentation we will overview the research and in particular the highly successful graduate training program in JAI.

Secondary electron emission from plasma processed accelerating cavity grade niobium

NASA Astrophysics Data System (ADS)

Basovic, Milos

Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated by different techniques. Specifically, this work provides the results of SEY from the plasma cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of plasma processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by electron beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) plasma. It is the goal of this research to determine the SEY on these two groups of samples before and after plasma processing as a function of the energy of primary electrons. The SEY as a function of the angle of incidence of the primary electrons is tested on the samples treated with Ar/O2 plasma.

Lattice design of the integrable optics test accelerator and optical stochastic cooling experiment at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kafka, Gene

2015-05-01

The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with signi cant exibility in mind, but without compromising cost e ciency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of di erent variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state ofmore » the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of- ight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.« less

Design of an X -band electron linear accelerator dedicated to decentralized 99Mo/99mTc supply: From beam energy selection to yield estimation

NASA Astrophysics Data System (ADS)

Jang, Jaewoong; Yamamoto, Masashi; Uesaka, Mitsuru

2017-10-01

The most frequently used radionuclide in diagnostic nuclear medicine, 99mTc, is generally obtained by the decay of its parent radionuclide, 99Mo. Recently, concerns have been raised over shortages of 99Mo/99mTc, owing to aging of the research reactors which have been supplying practically all of the global demand for 99Mo in a centralized fashion. In an effort to prevent such 99Mo/99mTc supply disruption and, furthermore, to ameliorate the underlying instability of the centralized 99Mo/99mTc supply chain, we designed an X -band electron linear accelerator which can be distributed over multiple regions, whereby 99Mo/99mTc can be supplied with improved accessibility. The electron beam energy was designed to be 35 MeV, at which an average beam power of 9.1 kW was calculated by the following beam dynamics analysis. Subsequent radioactivity modeling suggests that 11 of the designed electron linear accelerators can realize self-sufficiency of 99Mo/99mTc in Japan.

Lattice design of the integrable optics test accelerator and optical stochastic cooling experiment at Fermilab

NASA Astrophysics Data System (ADS)

Kafka, Gene

The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with significant flexibility in mind, but without compromising cost efficiency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of different variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state of the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of-flight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.

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

DOE PAGES

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

2016-10-01

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

International Linear Collider Technical Design Report (Volumes 1 through 4)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrison M.

2013-03-27

The design report consists of four volumes: Volume 1, Executive Summary; Volume 2, Physics; Volume 3, Accelerator (Part I, R and D in the Technical Design Phase, and Part II, Baseline Design); and Volume 4, Detectors.

Evaluation of the marginal fit of metal copings fabricated on three different marginal designs using conventional and accelerated casting techniques: an in vitro study.

PubMed

Vaidya, Sharad; Parkash, Hari; Bhargava, Akshay; Gupta, Sharad

2014-01-01

Abundant resources and techniques have been used for complete coverage crown fabrication. Conventional investing and casting procedures for phosphate-bonded investments require a 2- to 4-h procedure before completion. Accelerated casting techniques have been used, but may not result in castings with matching marginal accuracy. The study measured the marginal gap and determined the clinical acceptability of single cast copings invested in a phosphate-bonded investment with the use of conventional and accelerated methods. One hundred and twenty cast coping samples were fabricated using conventional and accelerated methods, with three finish lines: Chamfer, shoulder and shoulder with bevel. Sixty copings were prepared with each technique. Each coping was examined with a stereomicroscope at four predetermined sites and measurements of marginal gaps were documented for each. A master chart was prepared for all the data and was analyzed using Statistical Package for the Social Sciences version. Evidence of marginal gap was then evaluated by t-test. Analysis of variance and Post-hoc analysis were used to compare two groups as well as to make comparisons between three subgroups . Measurements recorded showed no statistically significant difference between conventional and accelerated groups. Among the three marginal designs studied, shoulder with bevel showed the best marginal fit with conventional as well as accelerated casting techniques. Accelerated casting technique could be a vital alternative to the time-consuming conventional casting technique. The marginal fit between the two casting techniques showed no statistical difference.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cline, David B.

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

Flowing DPF Design for Propulsion Experiments

DTIC Science & Technology

1993-08-01

plasma acceleration but not a pinch i.e., added fusion energy , as envisioned in a DPF. The outer electrode at the UI DPF is constructed of 24 rods which...many respects to a coaxial plasma accelerator or a magnetic plasmoid accelerator, the added fusion energy supplied by the pinch step greatly enhances...modified DPF in space propulsion. Using a scaled-up model. From this model, the contribution of fusion energy to thrust and specific impulse is estimated

Basic design considerations for free-electron lasers driven by electron beams from RF accelerators

NASA Astrophysics Data System (ADS)

Gover, A.; Freund, H.; Granatstein, V. L.; McAdoo, J. H.; Tang, C.-M.

A design procedure and design criteria are derived for free-electron lasers driven by electron beams from RF accelerators. The procedure and criteria permit an estimate of the oscillation-buildup time and the laser output power of various FEL schemes: with waveguide resonator or open resonator, with initial seed-radiation injection or with spontaneous-emission radiation source, with a linear wiggler or with a helical wiggler. Expressions are derived for computing the various FEL parameters, allowing for the design and optimization of the FEL operational characteristics under ideal conditions or with nonideal design parameters that may be limited by technological or practical constraints. The design procedure enables one to derive engineering curves and scaling laws for the FEL operating parameters. This can be done most conveniently with a computer program based on flowcharts given in the appendices.

Maximum Acceleration Recording Circuit

NASA Technical Reports Server (NTRS)

Bozeman, Richard J., Jr.

1995-01-01

Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

Flexible and experimentally feasible shortcut to quantum Zeno dynamic passage

NASA Astrophysics Data System (ADS)

Li, Wenlin; Zhang, Fengyang; Jiang, Yunfeng; Li, Chong; Song, Heshan

2016-10-01

We propose and discuss a theoretical scheme to speed up Zeno dynamic passage by an external acceleration Hamiltonian. This scheme is a flexible and experimentally feasible acceleration because the acceleration Hamiltonian does not adhere rigidly to an invariant relationship, whereas it can be a more general form ∑uj (t)Hcj. Here Hcj can be arbitrarily selected without any limitation, and therefore one can always construct an acceleration Hamiltonian by only using realizable Hcj. Applying our scheme, we finally design an experimentally feasible Hamiltonian as an example to speed up an entanglement preparation passage.

Microparticle accelerator of unique design. [for micrometeoroid impact and cratering simulation

NASA Technical Reports Server (NTRS)

Vedder, J. F.

1978-01-01

A microparticle accelerator has been devised for micrometeoroid impact and cratering simulation; the device produces high-velocity (0.5-15 km/sec), micrometer-sized projectiles of any cohesive material. In the source, an electrodynamic levitator, single particles are charged by ion bombardment in high vacuum. The vertical accelerator has four drift tubes, each initially at a high negative voltage. After injection of the projectile, each tube is grounded in turn at a time determined by the voltage and charge/mass ratio to give four acceleration stages with a total voltage equivalent to about 1.7 MV.

Magnetic field design for a Penning ion source for a 200 keV electrostatic accelerator

NASA Astrophysics Data System (ADS)

Fathi, A.; Feghhi, S. A. H.; Sadati, S. M.; Ebrahimibasabi, E.

2017-04-01

In this study, the structure of magnetic field for a Penning ion source has been designed and constructed with the use of permanent magnets. The ion source has been designed and constructed for a 200 keV electrostatic accelerator. With using CST Studio Suite, the magnetic field profile inside the ion source was simulated and an appropriate magnetic system was designed to improve particle confinement. Designed system consists of two ring magnets with 9 mm distance from each other around the anode. The ion source was constructed and the cylindrical magnet and designed magnetic system were tested on the ion source. The results showed that the ignition voltage for ion source with the designed magnetic system is almost 300 V lower than the ion source with the cylindrical magnet. Better particle confinement causes lower voltage discharge to occur.

Computational electronics and electromagnetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shang, C C

The Computational Electronics and Electromagnetics thrust area serves as the focal point for Engineering R and D activities for developing computer-based design and analysis tools. Representative applications include design of particle accelerator cells and beamline components; design of transmission line components; engineering analysis and design of high-power (optical and microwave) components; photonics and optoelectronics circuit design; electromagnetic susceptibility analysis; and antenna synthesis. The FY-97 effort focuses on development and validation of (1) accelerator design codes; (2) 3-D massively parallel, time-dependent EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; andmore » (5) development of beam control algorithms coupled to beam transport physics codes. These efforts are in association with technology development in the power conversion, nondestructive evaluation, and microtechnology areas. The efforts complement technology development in Lawrence Livermore National programs.« less

Design of a Ram Accelerator mass launch system

NASA Technical Reports Server (NTRS)

1988-01-01

The Ram Accelerator, a chemically propelled, impulsive mass launch system, is presented as a viable concept for directly launching acceleration-insensitive payloads into low Earth orbit. The principles of propulsion are based on those of an airbreathing supersonic ramjet. The payload vehicle acts as the ramjet centerbody and travels through a fixed launch tube that acts as the ramjet outer cowling. The launch tube is filled with premixed gaseous fuel and oxidizer mixtures that combust at the base of the vehicle and produce thrust. Two modes of in-tube propulsion involving ramjet cycles are used in sequence to accelerate the vehicle from 0.7 km/sec to 9 km/sec. Requirements for placing a 2000 kg vehicle into a 500-km circular orbit, with a minimum amount of onboard rocket propellant for orbital maneuvers, are examined. It is shown that in-tube propulsion requirements dictate a launch tube length of 5.1 km to achieve an exit velocity of 9 km/sec, with peak accelerations not to exceed 1000 g's. Aerodynamic heating due to atmospheric transit requires minimal ablative protection and the vehicle retains a large percentage of its exit velocity. An indirect orbital insertion maneuver with aerobraking and two apogee burns is examined to minimize the required onboard propellant mass. An appropriate onboard propulsion system design to perform the required orbital maneuvers with minimum mass requirements is also determined. The structural designs of both the launch tube and the payload vehicle are examined using simple structural and finite element analysis for various materials.

New features in the design code Tlie

NASA Astrophysics Data System (ADS)

van Zeijts, Johannes

1993-12-01

We present features recently installed in the arbitrary-order accelerator design code Tlie. The code uses the MAD input language, and implements programmable extensions modeled after the C language that make it a powerful tool in a wide range of applications: from basic beamline design to high precision-high order design and even control room applications. The basic quantities important in accelerator design are easily accessible from inside the control language. Entities like parameters in elements (strength, current), transfer maps (either in Taylor series or in Lie algebraic form), lines, and beams (either as sets of particles or as distributions) are among the type of variables available. These variables can be set, used as arguments in subroutines, or just typed out. The code is easily extensible with new datatypes.

A Statistical Perspective on Highly Accelerated Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Edward V.

Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use ofmore » highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning the assumed relationship between the stress level and performance. In addition, this document contains recommendations for conducting more informative accelerated tests.« less

Design and development of data acquisition system for the Louisiana accelerated loading device : final report.

DOT National Transportation Integrated Search

1992-09-01

The Louisiana Transportation Research Center has established a Pavement Research Facility (PRF). The core of the PRF is a testing machine that is capable of conducting full-scale simulated and accelerated load testing of pavement materials, construct...

Autogenous accelerated curing of concrete cylinders. Part I, Strength results.

DOT National Transportation Integrated Search

1971-01-01

Forty-eight different concrete mixes were designed to investigate the influence of cement types (II, III, and V), cement contents (450, 550, and 650 lb. per cu. yd.), water-cement ratios (0.4, 0.5, and 0.6), admixtures (accelerator, retarder, and air...

Machine and radiation protection challenges of high energy/intensity accelerators: the role of Monte Carlo calculations

NASA Astrophysics Data System (ADS)

Cerutti, F.

2017-09-01

The role of Monte Carlo calculations in addressing machine protection and radiation protection challenges regarding accelerator design and operation is discussed, through an overview of different applications and validation examples especially referring to recent LHC measurements.

Autogenous accelerated curing of concrete cylinders. Part III, Temperature relationships.

DOT National Transportation Integrated Search

1971-01-01

Forty-eight different concrete mixes were designed to investigate the influence of cement types (II, III, and V), cement contents (450, 550, and 650 lb. per cu. yd.), water cement ratios (0.4, 0.5, and 0.6), admixtures (accelerator, retarder, and air...

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Discussion Session - Accelerator System Design (Part II) Tutors: C. Darve, J. Weisend II, Ph. Lebrun, A. Dabrowski, U. Raich Video Conference with the CERN Control Center. Experts in the field of Accelerator science will be available to answer the students questions. This session will link the CCC and SA (using Codec VC).

SuperB Progress Report for Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biagini, M.E.; Boni, R.; Boscolo, M.

2012-02-14

This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around themore » world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national laboratories. In Italy these may include INFN Frascati and the University of Pisa, in the United States SLAC, LBNL, BNL and several universities, in France IN2P3, LAPP, and Grenoble, in Russia BINP, in Poland Krakow University, and in the UK the Cockcroft Institute. The construction time for this collider is a total of about four years. The new tunnel can be bored in about a year. The new accelerator components can be built and installed in about 4 years. The shipping of components from PEP-II at SLAC to Italy will take about a year. A new linac and damping ring complex for the injector for the rings can be built in about three years. The commissioning of this new accelerator will take about a year including the new electron and positron sources, new linac, new damping ring, new beam transport lines, two new collider rings and the Interaction Region. The new particle physics detector can be commissioned simultaneously with the accelerator. Once beam collisions start for particle physics, the luminosity will increase with time, likely reaching full design specifications after about two to three years of operation. After construction, the operation of the collider will be the responsibility of the Italian INFN governmental agency. The intent is to run this accelerator about ten months each year with about one month for accelerator turn-on and nine months for colliding beams. The collider will need to operate for about 10 years to provide the required 50 ab{sup -1} requested by the detector collaboration. Both beams as anticipated in this collider will have properties that are excellent for use as sources for synchrotron radiation (SR). The expected photon properties are comparable to those of PETRA-3 or NSLS-II. The beam lines and user facilities needed to carry out this SR program are being investigated.« less

Chip Scale, Ultra Sensitive Opto Mechanical Acceleration and Force Sensors

DTIC Science & Technology

2017-12-01

an accelerometer of the same mechanical design as that studied in part A. and shown in Fig. 3. One side of the zipper optical cavity is connected to...Ref. [13]. “Endevco 752A13” is Ref. [30]. “Zipper” is our own work on zipper photonic crystals from Ref. [31]. II Accelerometer Noise and Design ...limit, the shot noise of the light field also imparts a force on , and cause motion of, the mechanical resonator. The acceleration PSD due to back-action

Design Considerations for Proposed Fermilab Integrable RCS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldred, Jeffrey; Valishev, Alexander

2017-03-02

Integrable optics is an innovation in particle accelerator design that provides strong nonlinear focusing while avoiding parametric resonances. One promising application of integrable optics is to overcome the traditional limits on accelerator intensity imposed by betatron tune-spread and collective instabilities. The efficacy of high-intensity integrable accelerators will be undergo comprehensive testing over the next several years at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER). We propose an integrable Rapid-Cycling Synchrotron (iRCS) as a replacement for the Fermilab Booster to achieve multi-MW beam power for the Fermilab high-energy neutrino program. We provide amore » overview of the machine parameters and discuss an approach to lattice optimization. Integrable optics requires arcs with integer-pi phase advance followed by drifts with matched beta functions. We provide an example integrable lattice with features of a modern RCS - long dispersion-free drifts, low momentum compaction, superperiodicity, chromaticity correction, separate-function magnets, and bounded beta functions.« less

Cancellation control law for lateral-directional dynamics of a supermaneuverable aircraft

NASA Technical Reports Server (NTRS)

Snell, Antony

1993-01-01

Cancellation control laws are designed which reduce the high levels of lateral acceleration encountered during aggressive rolling maneuvers executed at high angle of attack. Two independent problem are examined. One is to reduce lateral acceleration at the mass center, while the other focuses on lateral acceleration at the pilot's station, located 7.0 m forward of the mass center. Both of these problems are challenging and somewhat different in their limitations. In each case the design is based on a linearization of the lateral-directional dynamics about a high angle of attack condition. The controllers incorporate dynamic inversion inner loops to provide control of stability-axis roll- and yaw-rates and then employ cancellation filters in both feed-forward and feed-back signal paths. The relative simplicity of the control laws should allow nonlinear generalizations to be devised. Although it is shown that lateral acceleration can be reduced substantially by such control laws, this is at the cost of slowed roll response, poor dutch-roll damping or a combination of the two.

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.

Compensation Techniques in Accelerator Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayed, Hisham Kamal

2011-05-01

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

Multi-Mode Cavity Accelerator Structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Yong; Hirshfield, Jay Leonard

2016-11-10

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

Bridging the gap between high and low acceleration for planetary escape

NASA Astrophysics Data System (ADS)

Indrikis, Janis; Preble, Jeffrey C.

With the exception of the often time consuming analysis by numerical optimization, no single orbit transfer analysis technique exists that can be applied over a wide range of accelerations. Using the simple planetary escape (parabolic trajectory) mission some of the more common techniques are considered as the limiting bastions at the high and the extremely low acceleration regimes. The brachistochrone, the minimum time of flight path, is proposed as the technique to bridge the gap between the high and low acceleration regions, providing a smooth bridge over the entire acceleration spectrum. A smooth and continuous velocity requirement is established for the planetary escape mission. By using these results, it becomes possible to determine the effect of finite accelerations on mission performance and target propulsion and power system designs which are consistent with a desired mission objective.

The NDCX-II engineering design

NASA Astrophysics Data System (ADS)

Waldron, W. L.; Abraham, W. J.; Arbelaez, D.; Friedman, A.; Galvin, J. E.; Gilson, E. P.; Greenway, W. G.; Grote, D. P.; Jung, J.-Y.; Kwan, J. W.; Leitner, M.; Lidia, S. M.; Lipton, T. M.; Reginato, L. L.; Regis, M. J.; Roy, P. K.; Sharp, W. M.; Stettler, M. W.; Takakuwa, J. H.; Volmering, J.; Vytla, V. K.

2014-01-01

The Neutralized Drift Compression Experiment (NDCX-II) is a user facility located at Lawrence Berkeley National Laboratory which is uniquely designed for ion-beam-driven high energy density laboratory physics and heavy ion fusion research. Construction was completed in March 2012 and the facility is now in the commissioning phase. A significant amount of engineering was carried out in order to meet the performance parameters required for a wide range of target heating experiments while making the most cost-effective use of high-value hardware available from a decommissioned high current electron induction accelerator. The technical challenges and design of this new ion induction accelerator facility are described.

Design of High Efficiency High Power Electron Accelerator Systems Based on Normal Conducting RF Technology for Energy and Environmental Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgashev, Valery; Tantawi, Sami

The goal of this project was to perform engineering design studies of three extremely high efficiency electron accelerators with the following parameters [1]: 2 MeV output beam energy and 1 MW average beam power; 10 MeV output energy and 10 MW; 10 MeV output energy and 1 MW. These linacs are intended for energy and environmental applications [2]. We based our designs on normal conducting radio-frequency technology. We have successfully reached this goal where we show rf-to-beam efficiency of 96.7 %, 97.2 %, and 79.6 % for these linacs.

Design Studies and Optimization of High-Field Nb$$_3$$Sn Dipole Magnets for a Future Very High Energy PP Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashikhin, V. V.; Novitski, I.; Zlobin, A. V.

2017-05-01

High filed accelerator magnets with operating fields of 15-16 T based on themore » $$Nb_3Sn$$ superconductor are being considered for the LHC energy upgrade or a future Very High Energy pp Collider. Magnet design studies are being conducted in the U.S., Europe and Asia to explore the limits of the $$Nb_3Sn$$ accelerator magnet technology while optimizing the magnet design and performance parame-ters, and reducing magnet cost. The first results of these studies performed at Fermilab in the framework of the US-MDP are reported in this paper.« less

HOM frequency control of SRF cavity in high current ERLs

NASA Astrophysics Data System (ADS)

Xu, Chen; Ben-Zvi, Ilan

2018-03-01

The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety of Energy Recovery Linac (ERL) applications.

Design, Modeling and Simulations in the RACE Project: Preliminary study for the development of a transport line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maidana, C. O.; Hunt, A. W.; Idaho State University, Department of Physics, PO Box 8106, Pocatello, ID 83209

2007-02-12

As part of the Reactor Accelerator Coupling Experiment (RACE) a set of preliminary studies were conducted to design a transport beam line that could bring a 25 MeV electron beam from a Linear Accelerator to a neutron-producing target inside a subcritical system. Because of the relatively low energy beam, the beam size and a relatively long beam line (implicating a possible divergence problem) different parameters and models were studied before a final design could be submitted for assembly. This report shows the first results obtained from different simulations of the transport line optics and dynamics.

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

NASA Astrophysics Data System (ADS)

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

2011-09-01

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

Field-Distortion Air-Insulated Switches for Next-Generation Pulsed-Power Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wisher, Matthew Louis; Johns, Owen M.; Breden, Eric Wayne

We have developed two advanced designs of a field-distortion air-insulated spark-gap switch that reduce the size of a linear-transformer-driver (LTD) brick. Both designs operate at 200 kV and a peak current of ~50 kA. At these parameters, both achieve a jitter of less than 2 ns and a prefire rate of ~0.1% over 5000 shots. We have reduced the number of switch parts and assembly steps, which has resulted in a more uniform, design-driven assembly process. We will characterize the performance of tungsten-copper and graphite electrodes, and two different electrode geometries. The new switch designs will substantially improve the electricalmore » and operational performance of next-generation pulsed-power accelerators.« less

Space-Charge Simulation of Integrable Rapid Cycling Synchrotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldred, Jeffery; Valishev, Alexander

2017-05-01

Integrable optics is an innovation in particle accelerator design that enables strong nonlinear focusing without generating parametric resonances. We use a Synergia space-charge simulation to investigate the application of integrable optics to a high-intensity hadron ring that could replace the Fermilab Booster. We find that incorporating integrability into the design suppresses the beam halo generated by a mismatched KV beam. Our integrable rapid cycling synchrotron (iRCS) design includes other features of modern ring design such as low momentum compaction factor and harmonically canceling sextupoles. Experimental tests of high-intensity beams in integrable lattices will take place over the next several yearsmore » at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER).« less

LEGO: A modular accelerator design code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Donald, M.; Irwin, J.

1997-08-01

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

Accelerating Mathematics Achievement Using Heterogeneous Grouping

ERIC Educational Resources Information Center

Burris, Carol Corbett; Heubert, Jay P.; Levin, Henry M.

2006-01-01

This longitudinal study examined the effects of providing an accelerated mathematics curriculum in heterogeneously grouped middle school classes in a diverse suburban school district. A quasi-experimental cohort design was used to evaluate subsequent completion of advanced high school math courses as well as academic achievement. Results showed…

Susceptibility of materials processing experiments to low-level accelerations

NASA Technical Reports Server (NTRS)

Naumann, R. J.

1981-01-01

The types of material processing experiments being considered for shuttle can be grouped into four categories: (1) contained solidification experiment; (2) quasicontainerless experiments; (3) containerless experiments; and (4) fluids experiments. Low level steady acceleration, compensated and uncompensated transient accelerations, and rotation induced flow factors that must be considered in the acceleration environment of a space vehicle whose importance depends on the type of experiment being performed. Some control of these factors may be exercised by the location and orientation of the experiment relative to shuttle and by the orbit vehicle attitude chosen for mission. The effects of the various residual accelerations can have serious consequence to the control of the experiment and must be factored into the design and operation of the apparatus.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hand, L.N.

Some proposed techniques for using laser beams to accelerate charged particles are reviewed. Two specific ideas for 'grating-type' accelerating structures are discussed. Speculations are presented about how a successful laser accelerator could be used in a 'multi-pass collider', a type of machine which would have characteristics intermediate between those of synchrotrons and linear (single-pass) colliders. No definite conclusions about practical structures for laser accelerators are reached, but it is suggested that a serious effort be made to design a small prototype machine. Achieving a reasonable luminosity demands that the accelerator either be a cw machine or that laser peak powermore » requirements be much higher than those presently available. Use of superconducting gratings requires a wavelength in the sub-millimeter range.« less

ILU industrial electron accelerators for medical-product sterilization and food treatment

NASA Astrophysics Data System (ADS)

Bezuglov, V. V.; Bryazgin, A. A.; Vlasov, A. Yu.; Voronin, L. A.; Panfilov, A. D.; Radchenko, V. M.; Tkachenko, V. O.; Shtarklev, E. A.

2016-12-01

Pulse linear electron accelerators of the ILU type have been developed and produced by the Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, for more than 30 years. Their distinctive features are simplicity of design, convenience in operation, and reliability during long work under conditions of industrial production. ILU accelerators have a range of energy of 0.7-10 MeV at a power of accelerated beam of up to 100 kW and they are optimally suitable for use as universal sterilizing complexes. The scientific novelty of these accelerators consists of their capability to work both in the electron-treatment mode of production and in the bremsstrahlung generation mode, which has high penetrating power.

Laser-driven electron beam and radiation sources for basic, medical and industrial sciences.

PubMed

Nakajima, Kazuhisa

2015-01-01

To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker's review article on "Laser Acceleration and its future" [Toshiki Tajima, (2010)],(1)) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated.

Synthesis of an optoelectronic system for tracking (OEST) the information track of the optical record carrier based on the acceleration control principle

NASA Astrophysics Data System (ADS)

Zalogin, Stanislav M.; Zalogin, M. S.

1997-02-01

The problem for construction of control algorithm in OEST the information track of the optical record carrier the realization of which is based on the use of accelerations is considered. Such control algorithms render the designed system the properties of adaptability, feeble sensitivity to the system parameter change and the action of disturbing forces what gives known advantages to information carriers with such system under operation in hard climate conditions as well as at maladjustment, workpieces wear and change of friction in the system. In the paper are investigated dynamic characteristics of a closed OEST, it is shown, that the designed stable system with given quality indices is a high-precision one. The validated recommendations as to design of control algorithms parameters are confirmed by results of mathematical simulation of controlled processes. The proposed methods for OEST synthesis on the basis of the control acceleration principle can be recommended for the use at industrial production of optical information record carriers.

Design study of an S-band RF cavity of a dual-energy electron LINAC for the CIS

NASA Astrophysics Data System (ADS)

Lee, Byeong-No; Park, Hyungdal; Song, Ki-baek; Li, Yonggui; Lee, Byung Cheol; Cha, Sung-su; Lee, Jong-Chul; Shin, Seung-Wook; Chai, Jong-seo

2014-01-01

The design of a resonance frequency (RF) cavity for the dual-energy S-band electron linear accelerator (LINAC) has been carried out for the cargo inspection system (CIS). This Standing-wave-type RF cavity is operated at a frequency under the 2856-MHz resonance frequency and generates electron beams of 9 MeV (high mode) and 6 MeV (low mode). The electrons are accelerated from the initial energy of the electron gun to the target energy (9 or 6 MeV) inside the RF cavity by using the RF power transmitted from a 5.5-MW-class klystron. Then, electron beams with a 1-kW average power (both high mode and low mode) bombard an X-ray target a 2-mm spot size. The proposed accelerating gradient was 13 MV/m, and the designed Q value was about 7100. On going research on 15-MeV non-destructive inspections for military or other applications is presented.

PIP-II Transfer Line Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vivoli, A.

The U.S. Particle Physics Project Prioritization Panel (P5) report encouraged the realization of Fermilab's Proton Improvement Plan II (PIP-II) to support future neutrino programs in the United States. PIP-II aims at enhancing the capabilities of the Fermilab existing accelerator complex while simultaneously providing a flexible platform for its future upgrades. The central part of PIP-II project is the construction of a new 800 MeV H- Superconducting (SC) Linac together with upgrades of the Booster and Main Injector synchrotrons. New transfer lines will also be needed to deliver beam to the down-stream accelerators and facilities. In this paper we present themore » recent development of the design of the transfer lines discussing the principles that guided their design, the constraints and requirements imposed by the existing accelerator complex and the following modifications implemented to comply with a better understanding of the limitations and further requirements that emerged during the development of the project.« less

Design of a low-cost, compact SRF accelerator for flue gas and wastewater treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ciovati, Gianluigi

2016-04-01

Funding is being requested pursuant to a proposal that was submitted and reviewed through the Portfolio Analysis and Management System (PAMS). PAMS Proposal ID: 222439. The proposed project consists of the design of a novel superconducting continuous-wave accelerator capable of providing a beam current of ~1 A at an energy of 1-2 MeV for the treatment of flue gases and wastewater streams. The novel approach consists on studying the feasibility of using a single-cell Nb cavity coated with a thin Nb3Sn layer of the inner surface and conductively cooled by to 4.2 K by cryocoolers inside a compact cryomodule. Themore » proposed study will include beam transport simulations, thermal and mechanical engineering analysis of the cryomodule and a cost analysis for both the fabrications costs and the operational and maintenance costs of such accelerator. The outcome of the project will be a report summarizing the analysis and results from the design study.« less

Accelerator Test of an Imaging Calorimeter

NASA Technical Reports Server (NTRS)

Christl, Mark J.; Adams, James H., Jr.; Binns, R. W.; Derrickson, J. H.; Fountain, W. F.; Howell, L. W.; Gregory, J. C.; Hink, P. L.; Israel, M. H.; Kippen, R. M.;

Pellet injector development at ORNL (Oak Ridge National Laboratory)

NASA Astrophysics Data System (ADS)

Gouge, M. J.; Argo, B. E.; Baylor, L. R.; Combs, S. K.; Fehling, D. T.; Fisher, P. W.; Foster, C. A.; Foust, C. R.; Milora, S. L.; Qualls, A. L.

1990-09-01

Advanced plasma fueling systems for magnetic confinement experiments are under development at Oak Ridge National Laboratory (ORNL). The general approach is that of producing and accelerating frozen hydrogenic pellets to speeds in the kilometer-per-second range by either pneumatic (light-gas gun) or mechanical (centrifugal force) techniques. ORNL has recently provided a centrifugal pellet injector for the Tore Supra tokamak and a new, simplified, eight-shot pneumatic injector for the Advanced Toroidal Facility stellarator at ORNL. Hundreds of tritium and DT pellets were accelerated at the Tritium Systems Test Assembly facility at Los Alamos in 1988 to 1989. These experiments, done in a single-shot pipe-gun system, demonstrated the feasibility of forming and accelerating tritium pellets at low (sup 3)He levels. A new, tritium-compatible extruder mechanism is being designed for longer-pulse DT applications. Two-stage light-gas guns and electron beam rocket accelerators for speeds of the order of 2 to 10 km/s are also under development. Recently, a repeating, two-stage light-gas gun accelerated 10 surrogate pellets at a 1-Hz repetition rate to speeds in the range of 2 to 3 km/s; and the electron beam rocket accelerator completed initial feasibility and scaling experiments. ORNL has also developed conceptual designs of advanced plasma fueling systems for the Compact Ignition Tokamak and the International Thermonuclear Experimental Reactor.

First heavy ion beam tests with a superconducting multigap CH cavity

NASA Astrophysics Data System (ADS)

Barth, W.; Aulenbacher, K.; Basten, M.; Busch, M.; Dziuba, F.; Gettmann, V.; Heilmann, M.; Kürzeder, T.; Miski-Oglu, M.; Podlech, H.; Rubin, A.; Schnase, A.; Schwarz, M.; Yaramyshev, S.

2018-02-01

Very compact accelerating-focusing structures, as well as short focusing periods, high accelerating gradients and short drift spaces are strongly required for superconducting (sc) accelerator sections operating at low and medium energies for continuous wave (cw) heavy ion beams. To keep the GSI-super heavy element (SHE) program competitive on a high level and even beyond, a standalone sc cw linac (Helmholtz linear accelerator) in combination with the GSI high charge state injector (HLI), upgraded for cw operation, is envisaged. Recently the first linac section (financed by Helmholtz Institute Mainz (HIM) and GSI) as a demonstration of the capability of 217 MHz multigap crossbar H-mode structures (CH) has been commissioned and extensively tested with heavy ion beam from the HLI. The demonstrator setup reached acceleration of heavy ions up to the design beam energy. The required acceleration gain was achieved with heavy ion beams even above the design mass to charge ratio at high beam intensity and full beam transmission. This paper presents systematic beam measurements with varying rf amplitudes and phases of the CH cavity, as well as phase space measurements for heavy ion beams with different mass to charge ratio. The worldwide first and successful beam test with a superconducting multigap CH cavity is a milestone of the R&D work of HIM and GSI in collaboration with IAP in preparation of the HELIAC project and other cw-ion beam applications.

Response of an Impact Test Apparatus for Fall Protective Headgear Testing Using a Hybrid-III Head/Neck Assembly

PubMed Central

Caccese, V.; Ferguson, J.; Lloyd, J.; Edgecomb, M.; Seidi, M.; Hajiaghamemar, M.

2017-01-01

A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus for use in the development of protective headgear designed to prevent injury due to falls. By including angular acceleration in the test protocol it becomes possible to assess and intentionally reduce this component of acceleration. Comparisons of standard and reduced durometer necks, various anvils, front, rear, and side drop orientations, and response data on performance of the apparatus are provided. Injury measures summarized for an unprotected drop include maximum linear and angular acceleration, head injury criteria (HIC), rotational injury criteria (RIC), and power rotational head injury criteria (PRHIC). Coefficient of variation for multiple drops ranged from 0.4 to 6.7% for linear acceleration. Angular acceleration recorded in a side drop orientation resulted in highest coefficient of variation of 16.3%. The drop test apparatus results in a reasonably repeatable test method that has potential to be used in studies of headgear designed to reduce head impact injury. PMID:28216804

Coastal marsh response to historical and future sea-level acceleration

USGS Publications Warehouse

Kirwan, M.; Temmerman, S.

2009-01-01

We consider the response of marshland to accelerations in the rate of sea-level rise by utilizing two previously described numerical models of marsh elevation. In a model designed for the Scheldt Estuary (Belgium-SW Netherlands), a feedback between inundation depth and suspended sediment concentrations allows marshes to quickly adjust their elevation to a change in sea-level rise rate. In a model designed for the North Inlet Estuary (South Carolina), a feedback between inundation and vegetation growth allows similar adjustment. Although the models differ in their approach, we find that they predict surprisingly similar responses to sea-level change. Marsh elevations adjust to a step change in the rate of sea-level rise in about 100 years. In the case of a continuous acceleration in the rate of sea-level rise, modeled accretion rates lag behind sea-level rise rates by about 20 years, and never obtain equilibrium. Regardless of the style of acceleration, the models predict approximately 6-14 cm of marsh submergence in response to historical sea-level acceleration, and 3-4 cm of marsh submergence in response to a projected scenario of sea-level rise over the next century. While marshes already low in the tidal frame would be susceptible to these depth changes, our modeling results suggest that factors other than historical sea-level acceleration are more important for observations of degradation in most marshes today.

LARP Long Quadrupole: A "Long" Step Toward an LHC

ScienceCinema

Giorgio Ambrosio

2017-12-09

The beginning of the development of Nb3Sn magnets for particle accelerators goes back to the 1960’s. But only very recently has this development begun to face the challenges of fabricating Nb3Sn magnets which can meet the requirements of modern particle accelerators. LARP (the LHC Accelerator Research Program) is leading this effort focusing on long models of the Interaction Region quadrupoles for a possible luminosity upgrade of the Large Hadron Collider. A major milestone in this development is to test, by the end of 2009, 4m-long quadrupole models, which will be the first Nb3Sn accelerator-type magnets approaching the length of real accelerator magnets. The Long Quadrupoles (LQ) are “Proof-of-Principle” magnets which are to demonstrate that Nb3Sn technology is sufficiently mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, under development at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. Several challenges must be addressed for the successful fabrication of long Nb3Sn coils and magnets. These challenges and the solutions adopted will be presented together with the main features of the LQ magnets. Several R&D lines are participating to this effort and their contributions will be also presented.

A variable acceleration calibration system

NASA Astrophysics Data System (ADS)

Johnson, Thomas H.

2011-12-01

A variable acceleration calibration system that applies loads using gravitational and centripetal acceleration serves as an alternative, efficient and cost effective method for calibrating internal wind tunnel force balances. Two proof-of-concept variable acceleration calibration systems are designed, fabricated and tested. The NASA UT-36 force balance served as the test balance for the calibration experiments. The variable acceleration calibration systems are shown to be capable of performing three component calibration experiments with an approximate applied load error on the order of 1% of the full scale calibration loads. Sources of error are indentified using experimental design methods and a propagation of uncertainty analysis. Three types of uncertainty are indentified for the systems and are attributed to prediction error, calibration error and pure error. Angular velocity uncertainty is shown to be the largest indentified source of prediction error. The calibration uncertainties using a production variable acceleration based system are shown to be potentially equivalent to current methods. The production quality system can be realized using lighter materials and a more precise instrumentation. Further research is needed to account for balance deflection, forcing effects due to vibration, and large tare loads. A gyroscope measurement technique is shown to be capable of resolving the balance deflection angle calculation. Long term research objectives include a demonstration of a six degree of freedom calibration, and a large capacity balance calibration.

Micro-Bubble Experiments at the Van de Graaff Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Z. J.; Wardle, Kent E.; Quigley, K. J.

In order to test and verify the experimental designs at the linear accelerator (LINAC), several micro-scale bubble ("micro-bubble") experiments were conducted with the 3-MeV Van de Graaff (VDG) electron accelerator. The experimental setups included a square quartz tube, sodium bisulfate solution with different concentrations, cooling coils, gas chromatography (GC) system, raster magnets, and two high-resolution cameras that were controlled by a LabVIEW program. Different beam currents were applied in the VDG irradiation. Bubble generation (radiolysis), thermal expansion, thermal convection, and radiation damage were observed in the experiments. Photographs, videos, and gas formation (O 2 + H 2) data were collected.more » The micro-bubble experiments at VDG indicate that the design of the full-scale bubble experiments at the LINAC is reasonable.« less

Beam dynamics design of the muon linac high-beta section

NASA Astrophysics Data System (ADS)

Kondo, Y.; Hasegawa, K.; Otani, M.; Mibe, T.; Yoshida, M.; Kitamura, R.

2017-07-01

A muon linac development for a new muon g-2 experiment is now going on at J-PARC. Muons from the muon beam line (H line) at the J-PARC muon science facility are once stopped in a silica-aerogel target, and room temperature muoniums are evaporated from the aerogel. They are dissociated with lasers, then accelerated up to 212 MeV using a linear accelerator. For the accelerating structure from 40 MeV, disk-loaded traveling-wave structure is applicable because the particle beta is more than 0.7. The structure itself is similar to that for electron linacs, however, the cell length should be harmonic to the increase of the particle velocity. In this paper, the beam dynamics design of this muon linac using the disk-loaded structure (DLS) is described.

Performance of Single Friction Pendulum bearing for isolated buildings subjected to seismic actions in Vietnam

NASA Astrophysics Data System (ADS)

Nguyen, N. V.; Nguyen, C. H.; Hoang, H. P.; Huong, K. T.

2018-04-01

Using structural control technology in earthquake resistant design of buildings in Vietnam is very limited. In this paper, a performance evaluation of using Single Friction Pendulum (SFP) bearing for seismically isolated buildings with earthquake conditions in Vietnam is presented. A two-dimensional (2-D) model of the 5-storey building subjected to earthquakes is analyzed in time domain. Accordingly, the model is analyzed for 2 cases: with and without SFP bearing. The ground acceleration data is selected and scaled to suit the design acceleration in Hanoi followed by the Standard TCVN 9386:2012. It is shown that the seismically isolated buildings gets the performance objectives while achieving an 91% reduction in the base shear, a significant decrease in the inter-story drift and absolute acceleration of each story.

Design study of high gradient, low impedance accelerating structures for the FERMI free electron laser linac upgrade

NASA Astrophysics Data System (ADS)

Shafqat, N.; Di Mitri, S.; Serpico, C.; Nicastro, S.

2017-09-01

The FERMI free-electron laser (FEL) of Elettra Sincrotrone Trieste, Italy, is a user facility driven by a 1.5 GeV 10-50 Hz S-band radiofrequency linear accelerator (linac), and it is based on an external laser seeding scheme that allows lasing at the shortest fundamental wavelength of 4 nm. An increase of the beam energy to 1.8 GeV at a tolerable breakdown rate, and an improvement of the final beam quality is desired in order to allow either lasing at 4 nm with a higher flux, or lasing at shorter wavelengths. This article presents the impedance analysis of newly designed S-band accelerating structures, for replacement of the existing backward travelling wave structures (BTWS) in the last portion of the FERMI linac. The new structure design promises higher accelerating gradient and lower impedance than those of the existing BTWS. Particle tracking simulations show that, with the linac upgrade, the beam relative energy spread, its linear and nonlinear z-correlation internal to the bunch, and the beam transverse emittances can be made smaller than the ones in the present configuration, with expected advantage to the FEL performance. The repercussion of the upgrade on the linac quadrupole magnets setting, for a pre-determined electron beam optics, is also considered.

Hypersonic MHD Propulsion System Integration for the Mercury Lightcraft

NASA Astrophysics Data System (ADS)

Myrabo, L. N.; Rosa, R. J.

2004-03-01

Introduced herein are the design, systems integration, and performance analysis of an exotic magnetohydrodynamic (MHD) slipstream accelerator engine for a single-occupant ``Mercury'' lightcraft. This ultra-energetic, laser-boosted vehicle is designed to ride a `tractor beam' into space, transmitted from a future orbital network of satellite solar power stations. The lightcraft's airbreathing combined-cycle engine employs a rotary pulsed detonation thruster mode for lift-off & landing, and an MHD slipstream accelerator mode at hypersonic speeds. The latter engine transforms the transatmospheric acceleration path into a virtual electromagnetic `mass-driver' channel; the hypersonic momentum exchange process (with the atmosphere) enables engine specific impulses in the range of 6000 to 16,000 seconds, and propellant mass fractions as low as 10%. The single-stage-to-orbit, highly reusable lightcraft can accelerate at 3 Gs into low Earth orbit with its throttle just barely beyond `idle' power, or virtually `disappear' at 30 G's and beyond. The objective of this advanced lightcraft design is to lay the technological foundations for a safe, very low cost (e.g., 1000X below chemical rockets) air and space transportation for human life in the mid-21st Century - a system that will be completely `green' and independent of Earth's limited fossil fuel reserves.

NASA Astrophysics Data System (ADS)

Kadyrov, E.; Evdokimenko, Y.; Kisel, V.; Kadyrov, V.; Worzala, F.

1994-12-01

Several designs of high-velocity oxygen fuel (HVOF) thermal spray systems have been created during the last decade. The most advanced systems are now producing coatings comparable in quality to detonation (D-gun) coatings. This paper presents numerical analysis of the interaction of dispersive particles with the carrying gas flow for three different HVOF systems, along with a method to calculate the parameters of sprayed particles that highlights the advantages and limitations of each design. The method includes gas dynamical calculations of the gas flow in an accelerating channel and calculations of the injected par-motion and thermal state (temperature and melted mass fraction). The calculations were performed for particles of tungsten carbide, aluminum oxide, and zirconium oxide with size distributions of 10 to 80 μm. Two conventional types of HVOF systems were considered: those with a supersonic accelerating channel and those with a subsonic accelerating channel (without a de Laval nozzle). A novel design is pro-posed that contains a combined gas dynamical path with functionally separated regions of heating and acceleration. The regularities and distinctions in the behavior of the metallic and ceramic oxide particles are discussed for different jet configurations. The results obtained indicate that it is possible to signifi-cantly affect particle parameters by using the new configuration solutions without creating construction complications.

Thermal Control Subsystem Design for the Avionics of a Space Station Payload

NASA Technical Reports Server (NTRS)

Moran, Matthew E.

1996-01-01

A case study of the thermal control subsystem development for a space based payload is presented from the concept stage through preliminary design. This payload, the Space Acceleration Measurement System 2 (SAMS-2), will measure the acceleration environment at select locations within the International Space Station. Its thermal control subsystem must maintain component temperatures within an acceptable range over a 10 year life span, while restricting accessible surfaces to touch temperature limits and insuring fail safe conditions in the event of loss of cooling. In addition to these primary design objectives, system level requirements and constraints are imposed on the payload, many of which are driven by multidisciplinary issues. Blending these issues into the overall system design required concurrent design sessions with the project team, iterative conceptual design layouts, thermal analysis and modeling, and hardware testing. Multiple tradeoff studies were also performed to investigate the many options which surfaced during the development cycle.

Computational electronics and electromagnetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shang, C. C.

The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domainmore » CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.« less

Electron Accelerator Shielding Design of KIPT Neutron Source Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Zhaopeng; Gohar, Yousry

The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biologicalmore » dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, similar to 0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose calculations. Two shielding materials, heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary less than 5.0e-03 mSv/h during operation. The shield configuration and parameters of the accelerator building were determined and are presented in this paper. Copyright (C) 2016, Published by Elsevier Korea LLC on behalf of Korean Nuclear Society.« less

Design, Test, and Acceptance Criteria for Helicopter Transparent Enclosures

DTIC Science & Technology

1978-11-01

point is a mass center of gravity at a specified station. Flight Path 24 YVertical Acceleration Pitching Acceleration N 2-51g = 1.89 rad/sec 2 Figure 59...rubber wiper blades would otherwise be incapable of abrading ntost windshield meterials . Aaratus The apparatus consisted of a specimen holding fixture

Accelerated testing for studying pavement design and performance (FY 2004) : thin bonded rigid overlay on PCCP and HMA (CISL experiment no. 13).

DOT National Transportation Integrated Search

2009-03-01

The thirteenth full-scale Accelerated Pavement Test (APT) experiment at the Civil Infrastructure Laboratory (CISL) : of Kansas State University aimed to determine the response and the failure mode of thin concrete overlays. Four : pavement structures...

Finite element simulation of structural performance on flexible pavements with stabilized base/treated subbase materials under accelerated loading : tech summary.

DOT National Transportation Integrated Search

2011-12-01

Accelerated pavement testing (APT) has been increasingly used by state highway agencies in recent years for evaluating pavement : design and performance through applying a simulative heavy vehicular load to the pavement section under controlled fi el...

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…

View of new centrifuge at Flight Acceleration Facility

NASA Technical Reports Server (NTRS)

1966-01-01

View of the new centrifuge at the Manned Spacecraft Center (MSC), located in the Flight Acceleration Facility, bldg 29. The 50-ft. arm can swing the three man gondola to create g-forces astronauts will experience during controlled flight and during reentry. The centrifuge was designed primarily for training Apollo astronauts.

Student Attitudes toward Accelerated Reader: "Thanks for Asking!"

ERIC Educational Resources Information Center

Smith, Amy; Westberg, Karen

2011-01-01

The Accelerated Reader program was designed by Renaissance Learning to increase students' motivation to read and students' achievement in reading; however, a review of the literature reveals inconsistent findings about its outcomes. The Renaissance Learning company reports several research studies on their website that suggest the program is…

Nontraditional Students, Accelerated Programs, Grade Expectations, and Instructor Evaluations

ERIC Educational Resources Information Center

Gershuny, Pamela; Rainey, Carolyn

2006-01-01

This article is intended as both a cautionary tale and an encouraging guide for instructors who are beginning to teach in accelerated programs designed to attract nontraditional students. This article is based, in part, on classroom action research conducted through surveys, observations, exams, and assessments, in an introductory business law…

Secondary Electron Emission from Plasma Processed Accelerating Cavity Grade Niobium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basovic, Milos

Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for highermore » energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated by different techniques. Specifically, this work provides the results of SEY from the plasma cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of plasma processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by electron beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) plasma. It is the goal of this research to determine the SEY on these two groups of samples before and after plasma processing as a function of the energy of primary electrons. The SEY as a function of the angle of incidence of the primary electrons is tested on the samples treated with Ar/O2 plasma.« less

Fast vaccine design and development based on correlates of protection (COPs)

PubMed Central

van Els, Cécile; Mjaaland, Siri; Næss, Lisbeth; Sarkadi, Julia; Gonczol, Eva; Smith Korsholm, Karen; Hansen, Jon; de Jonge, Jørgen; Kersten, Gideon; Warner, Jennifer; Semper, Amanda; Kruiswijk, Corine; Oftung, Fredrik

2014-01-01

New and reemerging infectious diseases call for innovative and efficient control strategies of which fast vaccine design and development represent an important element. In emergency situations, when time is limited, identification and use of correlates of protection (COPs) may play a key role as a strategic tool for accelerated vaccine design, testing, and licensure. We propose that general rules for COP-based vaccine design can be extracted from the existing knowledge of protective immune responses against a large spectrum of relevant viral and bacterial pathogens. Herein, we focus on the applicability of this approach by reviewing the established and up-coming COPs for influenza in the context of traditional and a wide array of new vaccine concepts. The lessons learnt from this field may be applied more generally to COP-based accelerated vaccine design for emerging infections. PMID:25424803

Timing and Characteristics of Cumulative Evidence Available on Novel Therapeutic Agents Receiving Food and Drug Administration Accelerated Approval.

PubMed

Naci, Huseyin; Wouters, Olivier J; Gupta, Radhika; Ioannidis, John P A

2017-06-01

Policy Points: Randomized trials-the gold standard of evaluating effectiveness-constitute a small minority of existing evidence on agents given accelerated approval. One-third of randomized trials are in therapeutic areas outside of FDA approval and less than half evaluate the therapeutic benefits of these agents but use them instead as common backbone treatments. Agents receiving accelerated approval are often tested concurrently in several therapeutic areas. For most agents, no substantial time lag is apparent between the average start dates of randomized trials evaluating their effectiveness and those using them as part of background therapies. There appears to be a tendency for therapeutic agents receiving accelerated approval to quickly become an integral component of standard treatment, despite potential shortcomings in their evidence base. Therapeutic agents treating serious conditions are eligible for Food and Drug Administration (FDA) accelerated approval. The clinical evidence accrued on agents receiving accelerated approval has not been systematically evaluated. Our objective was to assess the timing and characteristics of available studies. We first identified clinical studies of novel therapeutic agents receiving accelerated approval. We then (1) categorized those studies as randomized or nonrandomized, (2) explored whether they evaluated the FDA-approved indications, and (3) documented the available treatment comparisons. We also meta-analyzed the difference in start times between randomized studies that (1) did or did not evaluate approved indications and (2) were or were not designed to evaluate the agent's effectiveness. In total, 37 novel therapeutic agents received accelerated approval between 2000 and 2013. Our search of ClinicalTrials.gov identified 7,757 studies, which included 1,258,315 participants. Only one-third of identified studies were randomized controlled trials. Of 1,631 randomized trials with advanced recruitment status, 906 were conducted in therapeutic areas for which agents received initial accelerated approval, 202 were in supplemental indications, and 523 were outside approved indications. Only 411 out of 906 (45.4%) trials were designed to test the effectiveness of agents that received accelerated approval ("evaluation" trials); others used these agents as common background treatment in both arms ("background" trials). There was no detectable lag between average start times of trials conducted within and outside initially approved indications. Evaluation trials started on average 1.52 years (95% CI: 0.87 to 2.17) earlier than background trials. Cumulative evidence on agents with accelerated approvals has major limitations. Most clinical studies including these agents are small and nonrandomized, and about a third are conducted in unapproved areas, typically concurrently with those conducted in approved areas. Most randomized trials including these therapeutic agents are not designed to directly evaluate their clinical benefits but to incorporate them as standard treatment. © 2017 Milbank Memorial Fund.

Reduction of angular divergence of laser-driven ion beams during their acceleration and transport

NASA Astrophysics Data System (ADS)

Zakova, M.; Pšikal, Jan; Margarone, Daniele; Maggiore, Mario; Korn, G.

2015-05-01

Laser plasma physics is a field of big interest because of its implications in basic science, fast ignition, medicine (i.e. hadrontherapy), astrophysics, material science, particle acceleration etc. 100-MeV class protons accelerated from the interaction of a short laser pulse with a thin target have been demonstrated. With continuing development of laser technology, greater and greater energies are expected, therefore projects focusing on various applications are being formed, e.g. ELIMAIA (ELI Multidisciplinary Applications of laser-Ion Acceleration). One of the main characteristic and crucial disadvantage of ion beams accelerated by ultra-short intense laser pulses is their large divergence, not suitable for the most of applications. In this paper two ways how to decrease beam divergence are proposed. Firstly, impact of different design of targets on beam divergence is studied by using 2D Particlein-cell simulations (PIC). Namely, various types of targets include at foils, curved foil and foils with diverse microstructures. Obtained results show that well-designed microstructures, i.e. a hole in the center of the target, can produce proton beam with the lowest divergence. Moreover, the particle beam accelerated from a curved foil has lower divergence compared to the beam from a flat foil. Secondly, another proposed method for the divergence reduction is using of a magnetic solenoid. The trajectories of the laser accelerated particles passing through the solenoid are modeled in a simple Matlab program. Results from PIC simulations are used as input in the program. The divergence is controlled by optimizing the magnetic field inside the solenoid and installing an aperture in front of the device.

The chaotic dynamical aperture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.Y.; Tepikian, S.

1985-10-01

Nonlinear magnetic forces become more important for particles in the modern large accelerators. These nonlinear elements are introduced either intentionally to control beam dynamics or by uncontrollable random errors. Equations of motion in the nonlinear Hamiltonian are usually non-integrable. Because of the nonlinear part of the Hamiltonian, the tune diagram of accelerators is a jungle. Nonlinear magnet multipoles are important in keeping the accelerator operation point in the safe quarter of the hostile jungle of resonant tunes. Indeed, all the modern accelerator design have taken advantages of nonlinear mechanics. On the other hand, the effect of the uncontrollable random multipolesmore » should be evaluated carefully. A powerful method of studying the effect of these nonlinear multipoles is using a particle tracking calculation, where a group of test particles are tracing through these magnetic multipoles in the accelerator hundreds to millions of turns in order to test the dynamical aperture of the machine. These methods are extremely useful in the design of a large accelerator such as SSC, LEP, HERA and RHIC. These calculations unfortunately take tremendous amount of computing time. In this paper, we try to apply the existing method in the nonlinear dynamics to study the possible alternative solution. When the Hamiltonian motion becomes chaotic, the tune of the machine becomes undefined. The aperture related to the chaotic orbit can be identified as chaotic dynamical aperture. We review the method of determining chaotic orbit and apply the method to nonlinear problems in accelerator physics. We then discuss the scaling properties and effect of random sextupoles.« less

SIRIUS - A new 6 MV accelerator system for IBA and AMS at ANSTO

NASA Astrophysics Data System (ADS)

Pastuovic, Zeljko; Button, David; Cohen, David; Fink, David; Garton, David; Hotchkis, Michael; Ionescu, Mihail; Long, Shane; Levchenko, Vladimir; Mann, Michael; Siegele, Rainer; Smith, Andrew; Wilcken, Klaus

2016-03-01

The Centre for Accelerator Science (CAS) facility at ANSTO has been expanded with a new 6 MV tandem accelerator system supplied by the National Electrostatic Corporation (NEC). The beamlines, end-stations and data acquisition software for the accelerator mass spectrometry (AMS) were custom built by NEC for rare isotope mass spectrometry, while the beamlines with end-stations for the ion beam analysis (IBA) are largely custom designed at ANSTO. An overview of the 6 MV system and its performance during testing and commissioning phase is given with emphasis on the IBA end-stations and their applications for materials modification and characterisation.

Progress on the Multiphysics Capabilities of the Parallel Electromagnetic ACE3P Simulation Suite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kononenko, Oleksiy

2015-03-26

ACE3P is a 3D parallel simulation suite that is being developed at SLAC National Accelerator Laboratory. Effectively utilizing supercomputer resources, ACE3P has become a key tool for the coupled electromagnetic, thermal and mechanical research and design of particle accelerators. Based on the existing finite-element infrastructure, a massively parallel eigensolver is developed for modal analysis of mechanical structures. It complements a set of the multiphysics tools in ACE3P and, in particular, can be used for the comprehensive study of microphonics in accelerating cavities ensuring the operational reliability of a particle accelerator.

Particle tracking acceleration via signed distance fields in direct-accelerated geometry Monte Carlo

DOE PAGES

Shriwise, Patrick C.; Davis, Andrew; Jacobson, Lucas J.; ...

2017-08-26

Computer-aided design (CAD)-based Monte Carlo radiation transport is of value to the nuclear engineering community for its ability to conduct transport on high-fidelity models of nuclear systems, but it is more computationally expensive than native geometry representations. This work describes the adaptation of a rendering data structure, the signed distance field, as a geometric query tool for accelerating CAD-based transport in the direct-accelerated geometry Monte Carlo toolkit. Demonstrations of its effectiveness are shown for several problems. The beginnings of a predictive model for the data structure's utilization based on various problem parameters is also introduced.

Central region of SKKUCY-9 compact cyclotron

NASA Astrophysics Data System (ADS)

Jung, S. Y.; Kim, H. W.; Ghergherehchi, M.; Park, J. K.; Chai, J. S.; Kim, S. H.

2014-04-01

The development of a 9 MeV compact cyclotron for the production of radioisotopes for medical applications has been recently completed. The machine accelerates negative hydrogen ions generated from an internal PIG (Penning Ion Gauge) ion source following spiral orbits. Some of the structures designed for early beam acceleration, including a pair of center poles providing ions a circular direction, the head of the ion source, and the electrodes, are located in the center of the cyclotron. In this paper we discuss and evaluate the design of the central region that pulls the ions from the chimney of the ion source and directs them into the equilibrium orbit. The magnetic field produced by the center poles was analyzed using the magnetic solver in OPERA-3D TOSCA, and the phase error and ion equilibrium orbit, which is dependent on the kinetic energy within the designed field, were calculated using CYCLONE v8.4. The electric field produced in the acceleration gap was designed using an electrostatic solver. Then, the single beam trajectory was calculated by our own Cyclotron Beam Dynamics (CBD) code. The early orbits, vertical oscillation, acceptable RF phase and the energy gain during the early turns was evaluated. Final goal was to design the central region by the iterative optimization process and verify it with 1 MeV beam experiment.

Leveraging FPGAs for Accelerating Short Read Alignment.

PubMed

Arram, James; Kaplan, Thomas; Luk, Wayne; Jiang, Peiyong

2017-01-01

One of the key challenges facing genomics today is how to efficiently analyze the massive amounts of data produced by next-generation sequencing platforms. With general-purpose computing systems struggling to address this challenge, specialized processors such as the Field-Programmable Gate Array (FPGA) are receiving growing interest. The means by which to leverage this technology for accelerating genomic data analysis is however largely unexplored. In this paper, we present a runtime reconfigurable architecture for accelerating short read alignment using FPGAs. This architecture exploits the reconfigurability of FPGAs to allow the development of fast yet flexible alignment designs. We apply this architecture to develop an alignment design which supports exact and approximate alignment with up to two mismatches. Our design is based on the FM-index, with optimizations to improve the alignment performance. In particular, the n-step FM-index, index oversampling, a seed-and-compare stage, and bi-directional backtracking are included. Our design is implemented and evaluated on a 1U Maxeler MPC-X2000 dataflow node with eight Altera Stratix-V FPGAs. Measurements show that our design is 28 times faster than Bowtie2 running with 16 threads on dual Intel Xeon E5-2640 CPUs, and nine times faster than Soap3-dp running on an NVIDIA Tesla C2070 GPU.

On the Relativistic Correction of Particles Trajectory in Tandem Type Electrostatic Accelerator

NASA Astrophysics Data System (ADS)

Minárik, Stanislav

2015-08-01

A constant potential is applied to the acceleration of the ion-beam in the tandem type electrostatic accelerator. However, not just one voltage is applied, but instead a number of applications can be made in succession by means of the tandem arrangement of high voltage tubes. This number of voltage applications, which is the number of so-called "stages" of a tandem accelerator, may be two, three, or four, depending on the chosen design. Electrostatic field with approximately constant intensity acts on ions in any stage. In general, non-relativistic dynamics is used for the description of the ion transport in tandem accelerator. Energies of accelerated ions are too low and relativistic effects cannot be commonly observed by standard experimental technique. Estimation of possible relativistic correction of ion trajectories is therefore only a matter of calculation. In this note, we briefly present such calculation. Our aim is to show how using the relativistic dynamics modifies the particles trajectory in tandem type accelerator and what parameters determine this modification.

A -100 kV Power Supply for Ion Acceleration in Space-based Mass Spectrometers

NASA Astrophysics Data System (ADS)

Gilbert, J. A.; Zurbuchen, T.; Battel, S.

2017-12-01

High voltage power supplies are used in many space-based time-of-flight (TOF) mass spectrometer designs to accelerate incoming ions and increase the probability of their measurement and proper identification. Ions are accelerated in proportion to their charge state, so singly charged ions such as pickup ions are accelerated less than their multiple-charge state solar wind counterparts. This lack of acceleration results in pickup ion measurements with lower resolution and without determinations of absolute energy. Acceleration reduces the effects of angular scattering and energy straggling when ions pass through thin membranes such as carbon foils, and it brings ion energies above the detection threshold of traditional solid state detectors. We have developed a power supply capable of operating at -100 kV for ion acceleration while also delivering up to 10 W of power for the operation of a floating TOF system. We also show results of benchtop calibration and ion beam tests to demonstrate the functionality and success of this approach.

A Review of Microgravity Levels on Ten OARE Shuttle Missions

NASA Technical Reports Server (NTRS)

McPherson, Kevin M.

1998-01-01

The Orbital Acceleration Research Experiment (OARE) is an accelerometer package with nano-g sensitivity and on-orbit bias calibration capabilities. The OARE consists of a three axis miniature electrostatic accelerometer (MESA), a full in-flight bias and scale factor calibration station, and an on-board microprocessor for experiment control and data storage. Originally designed to measure and record the aerodynamic acceleration environment of the NASA Space Shuttles during re-entry, the OARE has been used on ten shuttle missions to measure the quasi-steady acceleration environment (<1 Hz) of the Orbiter while in low-Earth orbit. The effects on the quasi-steady acceleration environment from Orbiter systems, Orbiter attitude, Orbiter altitude, and crew activity are well understood as a result of these ten shuttle missions. This knowledge of the quasi-steady acceleration realm has direct application to understanding the quasi-steady acceleration environment expected for the International Space Station (ISS). This paper will summarize the more salient aspects of this quasi-steady acceleration knowledge base.

Co-evolution of upstream waves and accelerated ions at parallel shocks

NASA Astrophysics Data System (ADS)

Fujimoto, M.; Sugiyama, T.

2016-12-01

Shock waves in space plasmas have been considered as the agents for various particle acceleration phenomena. The basic idea behind shock acceleration is that particles are accelerated as they move back-and-forth across a shock front. Detailed studies of ion acceleration at the terrestrial bow shock have been performed, however, the restricted maximum energies attained prevent a straight-forward application of obtained knowledge to more energetic astrophysical situations. Here we show by a large-scale self-consistent particle simulation that the co-evolution of magnetic turbulence and accelerated ion population is the foundation for continuous operation of shock acceleration to ever higher energies. Magnetic turbulence is created by ions reflected back upstream of a parallel shock front. The co-evolution arises because more energetic ions excite waves of longer wavelengths, and because longer wavelength modes are capable of scattering (in the upstream) and reflecting (at the shock front) more energetic ions. Via carefully designed numerical experiments, we show very clearly that this picture is true.

An Expert System For Tuning Particle-Beam Accelerators

NASA Astrophysics Data System (ADS)

Lager, Darrel L.; Brand, Hal R.; Maurer, William J.; Searfus, Robert M.; Hernandez, Jose E.

1989-03-01

We have developed a proof-of-concept prototype of an expert system for tuning particle beam accelerators. It is designed to function as an intelligent assistant for an operator. In its present form it implements the strategies and reasoning followed by the operator for steering through the beam transport section of the Advanced Test Accelerator at Lawrence Livermore Laboratory's Site 300. The system is implemented in the language LISP using the Artificial Intelligence concepts of frames, daemons, and a representation we developed called a Monitored Decision Script.

First experimental results from 2 MeV proton tandem accelerator for neutron production.

PubMed

Kudryavtsev, A; Belchenko, Yu; Burdakov, A; Davydenko, V; Ivanov, A; Khilchenko, A; Konstantinov, S; Krivenko, A; Kuznetsov, A; Mekler, K; Sanin, A; Shirokov, V; Sorokin, I; Sulyaev, Yu; Tiunov, M

2008-02-01

A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction (7)Li(p,n)(7)Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction (13)C(p,gamma)(14)N, absorption in nitrogen.

Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Hyojae, E-mail: lkcom@ibs.re.kr; Jin, Hyunchang; Jang, Ji-Ho

2016-02-15

A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, developmentmore » of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.« less

Multiple beam induction accelerators for heavy ion fusion

NASA Astrophysics Data System (ADS)

Seidl, Peter A.; Barnard, John J.; Faltens, Andris; Friedman, Alex; Waldron, William L.

2014-01-01

Induction accelerators are appealing for heavy-ion driven inertial fusion energy (HIF) because of their high efficiency and their demonstrated capability to accelerate high beam current (≥10 kA in some applications). For the HIF application, accomplishments and challenges are summarized. HIF research and development has demonstrated the production of single ion beams with the required emittance, current, and energy suitable for injection into an induction linear accelerator. Driver scale beams have been transported in quadrupole channels of the order of 10% of the number of quadrupoles of a driver. We review the design and operation of induction accelerators and the relevant aspects of their use as drivers for HIF. We describe intermediate research steps that would provide the basis for a heavy-ion research facility capable of heating matter to fusion relevant temperatures and densities, and also to test and demonstrate an accelerator architecture that scales well to a fusion power plant.

AC magnetic field measurement using a small flip coil system for rapid cycling AC magnets at the China Spallation Neutron Source (CSNS)

NASA Astrophysics Data System (ADS)

Zhou, Jianxin; Kang, Wen; Li, Shuai; Liu, Yudong; Liu, Yiqin; Xu, Shouyan; Guo, Xiaoling; Wu, Xi; Deng, Changdong; Li, Li; Wu, Yuwen; Wang, Sheng

2018-02-01

The China Spallation Neutron Source (CSNS) has two major accelerator systems, a linear accelerator and a rapid cycling synchrotron (RCS). The RCS accelerator is used to accumulate and accelerate protons from the energy of 80 MeV to the design energy of 1.6 GeV at the repetition rate of 25 Hz, and extract the high energy beam to the target. The main magnets of the RCS accelerator are excited by AC current with DC bias. The magnetic field quality is very important for the RCS accelerator operation, since it should guarantee and focus a circulating beam. In order to characterize the AC magnets, a small flip coil measurement system has been developed and one of each type of AC magnets has been studied. The measurement system and selected measurement results are presented in this paper.

Effect of Gradual Onset +G(sub z) Acceleration on Rate of Visual Field Collapse and Intraocular Pressure

NASA Technical Reports Server (NTRS)

Haines, Richard F.; Rositano, Salvador A.; Greenleaf, John E.

1976-01-01

The mechanisms that control the size of the visual field during positive acceleration are poorly understood, but involve mainly the arterial blood pressure at the eye level and intraocular pressure (IOP) (3). Fluid and electrolyte shifts that occur in the general circulation during acceleration may well influence the rate at which the visual field collapses. This could, in turn, suggest the relative influences that arterial blood pressure, IOP, and various compensatory mechanisms have upon acceleration tolerance. Such knowledge could also be of use in the design and development of protective techniques for use in the acceleration environment. The present investigation was performed to study blood withdrawal (hypovolemia) and subsequent reinfusion, oral fluid replacement upon IOP, and the rate at which the visual field collapses during gradual onset +G(sub z) acceleration (0.5 G/min).

A novel electron accelerator for MRI-Linac radiotherapy.

PubMed

Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca

2016-03-01

MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility.

A novel electron accelerator for MRI-Linac radiotherapy

PubMed Central

Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca

2016-01-01

Purpose: MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Methods: Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. Results: For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Conclusions: Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility. PMID:26936713

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hogan, Mark

Plasma wakefield acceleration has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider is the focus of FACET, a National User Facility at SLAC. The existing FACET National User Facility uses part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and positrons. FACET-II is a new test facility to develop advanced acceleration and coherent radiationmore » techniques with high-energy electron and positron beams. It is the only facility in the world with high energy positron beams. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The design parameters for FACET-II are set by the requirements of the plasma wakefield experimental program. To drive the plasma wakefield requires a high peak current, in excess of 10kA. To reach this peak current, the electron and positron design bunch size is 10μ by 10μ transversely with a bunch length of 10μ. This is more than 200 times better than what has been achieved at the existing FACET. The beam energy is 10 GeV, set by the Linac length available and the repetition rate is up to 30 Hz. The FACET-II project is scheduled to be constructed in three major stages. Components of the project discussed in detail include the following: electron injector, bunch compressors and linac, the positron system, the Sector 20 sailboat and W chicanes, and experimental area and infrastructure.« less

Inter-Agency Consultative Group for Space Science (IACG): Handbook of Missions and Payloads

NASA Technical Reports Server (NTRS)

1994-01-01

The ACE spacecraft design is based on the Charge Composition Explorer (CCE) built by Johns Hopkins University (JHU) and the Applied Physics Lab (APL) for the AMPTE program. ACE is designed as a spinning spacecraft with its spin axis aligned to the Earth-Sun axis. The ACE launch weight will be approx. 633 kg, including 105 kg of scientific instruments and 184 kg of propellant. Using a Delta-class expendable launch vehicle, ACE will be launched into an L1 libration point (240 R(sub e)) orbit. Telemetry will be 6.7 kbps average, using tape recorder storage with daily readout to DSN. The experiment power requirement is approximately 76 W nominal and 96 W peak. The prime objective of the ACE mission is: (1) to determine accurate elemental and isotropic abundances including solar matter, local interstellar matter and local galactic matter; (2) to study the origin of elements and evolutionary processing in galactic nucleosynthesis, galactic evolution, origin and evolution of the solar system; (3) to study coronal formation and solar-wind acceleration processes; and (4) to study particle acceleration and transport, including coronal shock acceleration, stochastic flare acceleration, interplanetary shock acceleration, and interstellar acceleration and propagation. To accomplish this objective, ACE will perform comprehensive and coordinated determinations of the elemental and isotopic composition of energetic nuclei accelerated on the Sun, in interplanetary space, and from galactic sources. These observations will span five decades in energy, from solar wind to galactic cosmic ray energies, and will cover the element range from H-1 to Zr-40. Comparison of these samples of matter will be used to study the origin and subsequent evolution of both solar system and galactic material by isolating the effects of fundamental processes that include nucleosynthesis, charged and neutral particle separation, bulk plasma acceleration, and the acceleration of suprathermal and high-energy particles.

Thin Film Approaches to the SRF Cavity Problem Fabrication and Characterization of Superconducting Thin Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beringer, Douglas

Superconducting Radio Frequency (SRF) cavities are responsible for the acceleration of charged particles to relativistic velocities in most modern linear accelerators, such as those employed at high-energy research facilities like Thomas Jefferson National Laboratory’s CEBAF and the LHC at CERN. Recognizing SRF as primarily a surface phenomenon enables the possibility of applying thin films to the interior surface of SRF cavities, opening a formidable tool chest of opportunities by combining and designing materials that offer greater performance benefit. Thus, while improvements in radio frequency cavity design and refinements in cavity processing techniques have improved accelerator performance and efficiency – 1.5more » GHz bulk niobium SRF cavities have achieved accelerating gradients in excess of 35 MV/m – there exist fundamental material bounds in bulk superconductors limiting the maximally sustained accelerating field gradient (≈ 45 MV/m for Nb) where inevitable thermodynamic breakdown occurs. With state of the art Nb based cavity design fast approaching these theoretical limits, novel material innovations must be sought in order to realize next generation SRF cavities. One proposed method to improve SRF performance is to utilize thin film superconducting-insulating-superconducting (SIS) multilayer structures to effectively magnetically screen a bulk superconducting layer such that it can operate at higher field gradients before suffering critically detrimental SRF losses. This dissertation focuses on the production and characterization of thin film superconductors for such SIS layers for radio frequency applications. Correlated studies on structure, surface morphology and superconducting properties of epitaxial Nb and MgB2 thin films are presented.« less

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

The nonlinear finite element program MSC.Dytran was used to predict the impact pulse for (he drop test of an energy absorbing cellular structure. This pre-test simulation was performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. In addition, a goal of the simulation was to bound the acceleration pulse produced and delivered to the simulated space cargo container. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the enter of the EEV's cellular structure. The material models and failure criteria were varied to determine their effect on the resulting acceleration pulse. Pre-test analytical predictions using MSC.Dytran were compared with the test results obtained from impact test #4 using bungee accelerator located at the NASA Langley Research Center Impact Dynamics Research Facility. The material model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAMI model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for drop test #4.

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

NASA Astrophysics Data System (ADS)

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

1998-04-01

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

Purdue University National Biomedical Tracer Facility: Project definition phase. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, M.A.

The proposed National Biomedical Tracer Facility (NBTF) will house a high-current accelerator dedicated to production of short-lived radionuclides for biomedical and scientific research. The NBTF will play a vital role in repairing and maintaining the United States` research infrastructure for generation of essential accelerator-based radioisotopes. If properly designed and managed, the NBTF should also achieve international recognition as a Center-of-Excellence for research on radioisotope production methods and for associated education and training. The current report documents the results of a DOE-funded NBTF Project Definition Phase study carried out to better define the technical feasibility and projected costs of establishing andmore » operating the NBTF. This report provides an overview of recommended Facility Design and Specifications, including Accelerator Design, Building Design, and the associated Construction Cost Estimates and Schedule. It is recommended that the NBTF be established as an integrated, comprehensive facility for meeting the diverse production, research, and educational missions set forth in previous documents. Based on an analysis of the projected production demands that will be placed on the NBTF, it appears that a 70 MeV, 1 mA, negative ion cyclotron will offer a good balance between production capabilities and the costs of accelerator purchase and operation. A preliminary architectural plan is presented for a facility designed specifically to fulfill the functions of the NBTF in a cost-effective manner. This report also presents a detailed analysis of the Required Federal State, and Local Permits that may be needed to establish the NBTF, along with schedules and cost estimates for obtaining these permits. The Handling, Storage, and Disposal of Radioactive Waste will pose some significant challenges in the operation of the NBTF, but at this stage of planning the associated problems do not appear to be prohibitive.« less

Plasma production for electron acceleration by resonant plasma wave

NASA Astrophysics Data System (ADS)

Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Croia, M.; Curcio, A.; Di Giovenale, D.; Di Pirro, G. P.; Filippi, F.; Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R.; Romeo, S.; Ferrario, M.

2016-09-01

Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10-100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC_LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

GLADE: A Galaxy Catalogue for Multi-Messenger Searches in the Advanced Gravitational-Wave Detector Era

NASA Astrophysics Data System (ADS)

Dálya, G.; Galgóczi, G.; Dobos, L.; Frei, Z.; Heng, I. S.; Macas, R.; Messenger, C.; Raffai, P.; de Souza, R. S.

2018-06-01

We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localised electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA and SDSS-DR12Q. GLADE is complete up to d_L=37^{+3}_{-4} Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance dL, and contains all of the brightest galaxies giving half of the total B-band luminosity up to dL = 91 Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local universe.

3D graphics hardware accelerator programming methods for real-time visualization systems

NASA Astrophysics Data System (ADS)

Souetov, Andrew E.

2001-02-01

The paper deals with new approaches in software design for creating real-time applications that use modern graphics acceleration hardware. The growing complexity of such type of software compels programmers to use different types of CASE systems in design and development process. The subject under discussion is integration of such systems in a development process, their effective use, and the combination of these new methods with the necessity to produce optimal codes. A method of simulation integration and modeling tools in real-time software development cycle is described.

3D graphics hardware accelerator programming methods for real-time visualization systems

NASA Astrophysics Data System (ADS)

Souetov, Andrew E.

2000-02-01

The paper deals with new approaches in software design for creating real-time applications that use modern graphics acceleration hardware. The growing complexity of such type of software compels programmers to use different types of CASE systems in design and development process. The subject under discussion is integration of such systems in a development process, their effective use, and the combination of these new methods with the necessity to produce optimal codes. A method of simulation integration and modeling tools in real-time software development cycle is described.

Establishment of a National Accelerator Facility: Design and construction phase

NASA Astrophysics Data System (ADS)

1981-06-01

The main components of an accelerator facility for nuclear physics, isotope production, and radiotherapy in South Africa are in 8-MeV solid pole injector cyclotron and a separated sector cyclotron with a k-value of 200 MeV. Progress made in the development of the light ion injector and in the design of the control and beam transport systems is described. Mechanical and engineering tasks associated with component manufacture are discussed as well as the construction of the building to house the facility and the installation of necessary services.

A new IBA-AMS laboratory at the Comenius University in Bratislava (Slovakia)

NASA Astrophysics Data System (ADS)

Povinec, Pavel P.; Masarik, Jozef; Kúš, Peter; Holý, Karol; Ješkovský, Miroslav; Breier, Robert; Staníček, Jaroslav; Šivo, Alexander; Richtáriková, Marta; Kováčik, Andrej; Szarka, Ján; Steier, Peter; Priller, Alfred

2015-01-01

A Centre for Nuclear and Accelerator Technologies (CENTA) has been established at the Comenius University in Bratislava comprising of a tandem laboratory designed for Ion Beam Analysis (IBA), Ion Beam Modification (IBM) of materials and Accelerator Mass Spectrometry (AMS). The main equipment of the laboratory, i.e. Alphatross and MC-SNICS ion sources, 3 MV Pelletron tandem accelerator, and analyzers of accelerated ions are described. Optimization of ion beam characteristics for different ion sources with gas and solid targets, for transmission of accelerated ions with different energy and charge state, for different parameters of the high-energy ion analyzers, as well as first AMS results are presented. The scientific program of the CENTA will be devoted mainly to nuclear, environmental, life and material sciences.

Laser-driven electron beam and radiation sources for basic, medical and industrial sciences

PubMed Central

NAKAJIMA, Kazuhisa

2015-01-01

To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker’s review article on “Laser Acceleration and its future” [Toshiki Tajima, (2010)],1) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated. PMID:26062737

An investigation into the probabilistic combination of quasi-static and random accelerations

NASA Technical Reports Server (NTRS)

Schock, R. W.; Tuell, L. P.

1984-01-01

The development of design load factors for aerospace and aircraft components and experiment support structures, which are subject to a simultaneous vehicle dynamic vibration (quasi-static) and acoustically generated random vibration, require the selection of a combination methodology. Typically, the procedure is to define the quasi-static and the random generated response separately, and arithmetically add or root sum square to get combined accelerations. Since the combination of a probabilistic and a deterministic function yield a probabilistic function, a viable alternate approach would be to determine the characteristics of the combined acceleration probability density function and select an appropriate percentile level for the combined acceleration. The following paper develops this mechanism and provides graphical data to select combined accelerations for most popular percentile levels.

Initiation of combustion in the thermally choked ram accelerator

NASA Technical Reports Server (NTRS)

Bruckner, A. P.; Burnham, E. A.; Knowlen, C.; Hertzberg, A.; Bogdanoff, D. W.

1992-01-01

The methodology for initiating stable combustion in a ram accelerator operating in the thermally choked mode is presented in this paper. The ram accelerator is a high velocity ramjet-in-tube projectile launcher whose principle of operation is similar to that of an airbreathing ramjet. The subcaliber projectile travels supersonically through a stationary tube filled with a premixed combustible gas mixture. In the thermally choked propulsion mode subsonic combustion takes place behind the base of the projectile and leads to thermal choking, which stabilizes a normal shock system on the projectile, thus producing forward thrust. Projectiles with masses in the 45-90 g range have been accelerated to velocities up to 2650 m/sec in a 38 mm bore, 16 m long accelerator tube. Operation of the ram accelerator is started by injecting the projectile into the accelerator tube at velocities in the 700 - 1300 m/sec range by means of a conventional gas gun. A specially designed obturator, which seals the bore of the gun during this initial acceleration, enters the ram accelerator together with the projectile. The interaction of the obturator with the propellant gas ignites the gas mixture and establishes stable combustion behind the projectile.

HOM frequency control of SRF cavity in high current ERLs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Chen; Ben-Zvi, Ilan

The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety ofmore » Energy Recovery Linac (ERL) applications.« less

HOM frequency control of SRF cavity in high current ERLs

DOE PAGES

Xu, Chen; Ben-Zvi, Ilan

2017-12-06

The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety ofmore » Energy Recovery Linac (ERL) applications.« less

High powered rocketry: design, construction, and launching experience and analysis

NASA Astrophysics Data System (ADS)

Paulson, Pryce; Curtis, Jarret; Bartel, Evan; Owens Cyr, Waycen; Lamsal, Chiranjivi

2018-01-01

In this study, the nuts and bolts of designing and building a high powered rocket have been presented. A computer simulation program called RockSim was used to design the rocket. Simulation results are consistent with time variations of altitude, velocity, and acceleration obtained in the actual flight. The actual drag coefficient was determined by using altitude back-tracking method and found to be 0.825. Speed of the exhaust determined to be 2.5 km s-1 by analyzing the thrust curve of the rocket. Acceleration in the coasting phase of the flight, represented by the second-degree polynomial of a small leading coefficient, have been found to approach ‘-g’ asymptotically.

Development of the automated bunker door by using a microcontroller-system

NASA Astrophysics Data System (ADS)

Ahmad, M. A.; Leo, K. W.; Mohamad, G. H. P.; Ahmad, A.; Hashim, S. A.; Chulan, R. M.; Baijan, A. H.

2018-01-01

The new low energy electron beam accelerator bunker was designed and built locally to allocate a 500 keV electron beam accelerator at Block 43T in Malaysian Nuclear Agency. This bunker is equipped with a locally made radiation shielding door of 10 tons. Originally, this door is moving manually by a wheel and fitted with a gear system. However, it is still heavy and need longer time to operate it manually. To overcome those issues, a new automated control system has been designed and developed. In this paper, the complete steps and design of automated control system based on the microcontroller (PIC16F84A) is described.

Galium Electromagnetic (GEM) Thruster Concept and Design

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Markusic, Thomas E.

2005-01-01

We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagnetic pump. At a designated time, a pulsed discharge (approx. 10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx. 500 J), second-stage pulse which provides the primary electromagnetic (j x B) acceleration.

Ultra-High Gradient Channeling Acceleration in Nanostructures: Design/Progress of Proof-of-Concept (POC) Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Young Min; Green, A.; Lumpkin, A. H.

2016-09-16

A short bunch of relativistic particles or a short-pulse laser perturbs the density state of conduction electrons in a solid crystal and excites wakefields along atomic lattices in a crystal. Under a coupling condition the wakes, if excited, can accelerate channeling particles with TeV/m acceleration gradients in principle since the density of charge carriers (conduction electrons) in solids n 0 = ~ 10 20 – 10 23 cm -3 is significantly higher than what can be obtained in gaseous plasma. Nanostructures have some advantages over crystals for channeling applications of high power beams. The dechanneling rate can be reduced andmore » the beam acceptance increased by the large size of the channels. For beam-driven acceleration, a bunch length with a sufficient charge density would need to be in the range of the plasma wavelength to properly excite plasma wakefields, and channeled particle acceleration with the wakefields must occur before the ions in the lattices move beyond the restoring threshold. In the case of the excitation by short laser pulses, the dephasing length is appreciably increased with the larger channel, which enables channeled particles to gain sufficient amounts of energy. This paper describes simulation analyses on beam- and laser (X-ray)-driven accelerations in effective nanotube models obtained from Vsim and EPOCH codes. Experimental setups to detect wakefields are also outlined with accelerator facilities at Fermilab and NIU. In the FAST facility, the electron beamline was successfully commissioned at 50 MeV and it is being upgraded toward higher energies for electron accelerator R&D. The 50 MeV injector beamline of the facility is used for X-ray crystal-channeling radiation with a diamond target. It has been proposed to utilize the same diamond crystal for a channeling acceleration POC test. Another POC experiment is also designed for the NIU accelerator lab with time-resolved electron diffraction. Recently, a stable generation of single-cycle laser pulses with tens of Petawatt power based on thin film compression (TFC) technique has been investigated for target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA). The experimental plan with a nanometer foil is discussed with an available test facility such as Extreme Light Infrastructure – Nuclear Physics (ELI-NP).« less

Ultra-high gradient channeling acceleration in nanostructures: Design/progress of proof-of-concept (POC) experiments

NASA Astrophysics Data System (ADS)

Shin, Y. M.; Green, A.; Lumpkin, A. H.; Thurman-Keup, R. M.; Shiltsev, V.; Zhang, X.; Farinella, D. M.-A.; Taborek, P.; Tajima, T.; Wheeler, J. A.; Mourou, G.

2017-03-01

A short bunch of relativistic particles, or a short-pulse laser, perturb the density state of conduction electrons in a solid crystal and excite wakefields along atomic lattices in a crystal. Under a coupling condition between a driver and plasma, the wakes, if excited, can accelerate channeling particles with TeV/m acceleration gradients [1], in principle, since the density of charge carriers (conduction electrons) in solids n0 = 1020 - 1023 cm-3 is significantly higher than what was considered above in gaseous plasma. Nanostructures have some advantages over crystals for channeling applications of high power beams. The de-channeling rate can be reduced and the beam acceptance increased by the large size of the channels. For beam-driven acceleration, a bunch length with a sufficient charge density would need to be in the range of the plasma wavelength to properly excite plasma wakefields, and channeled particle acceleration with the wakefields must occur before the ions in the lattices move beyond the restoring threshold. In the case of the excitation by short laser pulses, the dephasing length is appreciably increased with the larger channel, which enables channeled particles to gain sufficient amounts of energy. This paper describes simulation analyses on beam- and laser (X-ray)-driven accelerations in effective nanotube models obtained from the Vsim and EPOCH codes. Experimental setups to detect wakefields are also outlined with accelerator facilities at Fermilab and Northern Illinois University (NIU). In the FAST facility, the electron beamline was successfully commissioned at 50 MeV, and it is being upgraded toward higher energies for electron accelerator R&D. The 50 MeV injector beamline of the facility is used for X-ray crystal-channeling radiation with a diamond target. It has been proposed to utilize the same diamond crystal for a channeling acceleration proof-of-concept (POC). Another POC experiment is also designed for the NIU accelerator lab with time-resolved electron diffraction. Recently, a stable generation of single-cycle laser pulses with tens of Petawatt power based on the thin film compression (TFC) technique has been investigated for target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA). The experimental plan with a nanometer foil is discussed with an available test facility such as Extreme Light Infrastructure - Nuclear Physics (ELI-NP).

Application of real-time digitization techniques in beam measurement for accelerators

NASA Astrophysics Data System (ADS)

Zhao, Lei; Zhan, Lin-Song; Gao, Xing-Shun; Liu, Shu-Bin; An, Qi

2016-04-01

Beam measurement is very important for accelerators. In this paper, modern digital beam measurement techniques based on IQ (In-phase & Quadrature-phase) analysis are discussed. Based on this method and high-speed high-resolution analog-to-digital conversion, we have completed three beam measurement electronics systems designed for the China Spallation Neutron Source (CSNS), Shanghai Synchrotron Radiation Facility (SSRF), and Accelerator Driven Sub-critical system (ADS). Core techniques of hardware design and real-time system calibration are discussed, and performance test results of these three instruments are also presented. Supported by National Natural Science Foundation of China (11205153, 10875119), Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the Fundamental Research Funds for the Central Universities (WK2030040029),and the CAS Center for Excellence in Particle Physics (CCEPP).

RF emittance in a low energy electron linear accelerator

NASA Astrophysics Data System (ADS)

Sanaye Hajari, Sh.; Haghtalab, S.; Shaker, H.; Kelisani, M. Dayyani

2018-04-01

Transverse beam dynamics of an 8 MeV low current (10 mA) S-band traveling wave electron linear accelerator has been studied and optimized. The main issue is to limit the beam emittance, mainly induced by the transverse RF forces. The linac is being constructed at Institute for Research in Fundamental Science (IPM), Tehran Iran Labeled as Iran's First Linac, nearly all components of this accelerator are designed and constructed within the country. This paper discusses the RF coupler induced field asymmetry and the corresponding emittance at different focusing levels, introduces a detailed beam dynamics design of a solenoid focusing channel aiming to reduce the emittance growth and studies the solenoid misalignment tolerances. In addition it has been demonstrated that a prebuncher cavity with appropriate parameters can help improving the beam quality in the transverse plane.

A scintillator-based online detector for the angularly resolved measurement of laser-accelerated proton spectra.

PubMed

Metzkes, J; Karsch, L; Kraft, S D; Pawelke, J; Richter, C; Schürer, M; Sobiella, M; Stiller, N; Zeil, K; Schramm, U

2012-12-01

In recent years, a new generation of high repetition rate (~10 Hz), high power (~100 TW) laser systems has stimulated intense research on laser-driven sources for fast protons. Considering experimental instrumentation, this development requires online diagnostics for protons to be added to the established offline detection tools such as solid state track detectors or radiochromic films. In this article, we present the design and characterization of a scintillator-based online detector that gives access to the angularly resolved proton distribution along one spatial dimension and resolves 10 different proton energy ranges. Conceived as an online detector for key parameters in laser-proton acceleration, such as the maximum proton energy and the angular distribution, the detector features a spatial resolution of ~1.3 mm and a spectral resolution better than 1.5 MeV for a maximum proton energy above 12 MeV in the current design. Regarding its areas of application, we consider the detector a useful complement to radiochromic films and Thomson parabola spectrometers, capable to give immediate feedback on the experimental performance. The detector was characterized at an electrostatic Van de Graaff tandetron accelerator and tested in a laser-proton acceleration experiment, proving its suitability as a diagnostic device for laser-accelerated protons.

Computational screening of organic polymer dielectrics for novel accelerator technologies

DOE PAGES

Pilania, Ghanshyam; Weis, Eric; Walker, Ethan M.; ...

2018-06-18

The use of infrared lasers to power accelerating dielectric structures is a developing area of research. Within this technology, the choice of the dielectric material forming the accelerating structures, such as the photonic band gap (PBG) structures, is dictated by a range of interrelated factors including their dielectric and optical properties, amenability to photo-polymerization, thermochemical stability and other target performance metrics of the particle accelerator. In this direction, electronic structure theory aided computational screening and design of dielectric materials can play a key role in identifying potential candidate materials with the targeted functionalities to guide experimental synthetic efforts. In anmore » attempt to systematically understand the role of chemistry in controlling the electronic structure and dielectric properties of organic polymeric materials, here we employ empirical screening and density functional theory (DFT) computations, as a part of our multi-step hierarchal screening strategy. Our DFT based analysis focused on the bandgap, dielectric permittivity, and frequency-dependent dielectric losses due to lattice absorption as key properties to down-select promising polymer motifs. In addition to the specific application of dielectric laser acceleration, the general methodology presented here is deemed to be valuable in the design of new insulators with an attractive combination of dielectric properties.« less

Framework for Development and Distribution of Hardware Acceleration

NASA Astrophysics Data System (ADS)

Thomas, David B.; Luk, Wayne W.

2002-07-01

This paper describes IGOL, a framework for developing reconfigurable data processing applications. While IGOL was originally designed to target imaging and graphics systems, its structure is sufficiently general to support a broad range of applications. IGOL adopts a four-layer architecture: application layer, operation layer, appliance layer and configuration layer. This architecture is intended to separate and co-ordinate both the development and execution of hardware and software components. Hardware developers can use IGOL as an instance testbed for verification and benchmarking, as well as for distribution. Software application developers can use IGOL to discover hardware accelerated data processors, and to access them in a transparent, non-hardware specific manner. IGOL provides extensive support for the RC1000-PP board via the Handel-C language, and a wide selection of image processing filters have been developed. IGOL also supplies plug-ins to enable such filters to be incorporated in popular applications such as Premiere, Winamp, VirtualDub and DirectShow. Moreover, IGOL allows the automatic use of multiple cards to accelerate an application, demonstrated using DirectShow. To enable transparent acceleration without sacrificing performance, a three-tiered COM (Component Object Model) API has been designed and implemented. This API provides a well-defined and extensible interface which facilitates the development of hardware data processors that can accelerate multiple applications.

CBETA Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffstaetter, G.; Trbojevic, D.; Mayes, C.

This Design Report describes the baseline design of the Cornell-BNL ERL Test Accelerator, as it exists on the date of its publication in June 2017. The Design Report will not change frequently in the future. In contrast, the parameter sheets that summarize the CBETA design will respond as quickly and as thoroughly as necessary to maintain con guration control.

CBETA Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffstaetter, G.; Trbojevic, D.; Mayes, C.

This Design Report describes the baseline design of the Cornell-BNL ERL Test Accelerator, as it exists on the date of its publication in June 2017. The Design Report will not change frequently in the future. In contrast, the parameter sheets that summarize the CBETA design will respond as quickly and as thoroughly as necessary to maintain configuration control.

The Value of Digital Tutoring and Accelerated Expertise for Military Veterans

ERIC Educational Resources Information Center

Fletcher, J. D.

2017-01-01

This report concerns use of a digital tutor to accelerate veterans' acquisition of expertise and improve their preparation for the civilian workforce. As background, it briefly discusses the need to improve veterans' employability, the technology of digital tutoring, its ability to produce advanced levels of technical expertise, and the design,…

Selected List of Low Energy Beam Transport Facilities for Light-Ion, High-Intensity Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prost, L. R.

This paper presents a list of Low Energy Beam Transport (LEBT) facilities for light-ion, high-intensity accelerators. It was put together to facilitate comparisons with the PXIE LEBT design choices. A short discussion regarding the importance of the beam perveance in the choice of the transport scheme follows.

A Light Clock Satisfying the Clock Hypothesis of Special Relativity

ERIC Educational Resources Information Center

West, Joseph

2007-01-01

The design of the FMEL, a floor-mirrored Einstein-Langevin "light clock", is introduced. The clock provides a physically intuitive manner to calculate and visualize the time dilation effects for a spatially extended set of observers (an accelerated "frame") undergoing unidirectional acceleration or observers on a rotating cylinder of constant…

Potential Application of Magnetohydrodynamic Acceleration to Hypersonic Environmental Testing

DTIC Science & Technology

1990-08-01

homopolar generators, and compulsators should be evaluated along with solid-state converters. 86 AEDC-TR-90-6 B.4.2 Design Study of Control and...heater as a source of hot air for accelerator research. One could consider using motor generator power supplies for the arc heater as d3ne tor the

Effects of a Modified Thinking Science Program for Year 8 Students of Various Abilities

ERIC Educational Resources Information Center

Mobbs, Ellen

2016-01-01

The aim of this research was to identify whether students of various academic abilities would achieve positive gains in cognitive ability after completing a modified cognitive acceleration program based on the Cognitive Acceleration through Science Education (CASE) program. This research was quasi-experimental in design, with small samples of…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galambos, John D.; Anderson, David E.; Bechtol, D.

The Second Target Station (STS) is a proposed upgrade for SNS. It includes a doubling of the accelerator power and an additional instrument hall. The new instrument hall will receive a 467 kW 10 Hz beam. The parameters and preliminary design aspects of the STS are presented for the accelerator, target systems, instrument hall, instruments and civil construction aspects.

Supplementing Accelerated Reading with Classwide Interdependent Group-Oriented Contingencies

ERIC Educational Resources Information Center

Pappas, Danielle N.; Skinner, Christopher H.; Skinner, Amy L.

2010-01-01

An across-groups (classrooms), multiple-baseline design was used to investigate the effects of an interdependent group-oriented contingency on the Accelerated Reader (AR) performance of fourth-grade students. A total of 32 students in three classes participated. Before the study began, an independent group-oriented reward program was being applied…

Critical Thinking Skill Acquisition in Accelerated LVN to RN Nursing Programs: An Evaluative Case Study

ERIC Educational Resources Information Center

Hutchison, Billy Eugene

2013-01-01

Accelerated transitional nursing programs (ATNPs) designed specifically for licensed vocational nurses (LVNs) to transition to become registered nurses (RNs) are graduating novice nurses who need critical thinking skills to solve patient problems. The health care industry and patient outcomes depend on graduate nurses to be proficient with quality…

A Quantitative Analysis of Methods Used for Avoidance and Acceleration of Developmental Mathematics Sequences in Community College

ERIC Educational Resources Information Center

Travers, Steven T.

2017-01-01

Many developmental mathematics programs at community colleges in recent years have undergone a process of redesign in an attempt increase the historical poor rate of student successful completion of required developmental coursework. Various curriculum and instructional design models that incorporate methods of avoiding and accelerating the…

Accelerating Change for Women Faculty of Color in STEM: Policy, Action, and Collaboration

ERIC Educational Resources Information Center

Hess, Cynthia; Gault, Barbara; Yi, Youngmin

2013-01-01

This report summarizes findings and recommendations from a convening, "Accelerating Change for Women Faculty of Color in STEM: Policy, Action, and Collaboration," that was designed to address the underrepresentation of women of color in STEM academic careers. The convening provided an opportunity for individuals who work in various…

Learning at the Speed of Light: Deep Learning and Accelerated Online Graduate Courses

ERIC Educational Resources Information Center

Trekles, Anastasia M.

2013-01-01

An increasing number of university programs, particularly at the graduate level, are moving to an accelerated, time-compressed model for online degree offerings. However, the literature revealed that research in distance education effectiveness is still confounded by many variables, including course design and student approach to learning.…

Magnetohydrodynamic Augmented Propulsion Experiment: I. Performance Analysis and Design

NASA Technical Reports Server (NTRS)

Litchford, R. J.; Cole, J. W.; Lineberry, J. T.; Chapman, J. N.; Schmidt, H. J.; Lineberry, C. W.

2003-01-01

The performance of conventional thermal propulsion systems is fundamentally constrained by the specific energy limitations associated with chemical fuels and the thermal limits of available materials. Electromagnetic thrust augmentation represents one intriguing possibility for improving the fuel composition of thermal propulsion systems, thereby increasing overall specific energy characteristics; however, realization of such a system requires an extremely high-energy-density electrical power source as well as an efficient plasma acceleration device. This Technical Publication describes the development of an experimental research facility for investigating the use of cross-field magnetohydrodynamic (MHD) accelerators as a possible thrust augmentation device for thermal propulsion systems. In this experiment,a 1.5-MW(sub e) Aerotherm arc heater is used to drive a 2-MW(sub e) MHD accelerator. The heatsink MHD accelerator is configured as an externally diagonalized, segmented channel, which is inserted into a large-bore, 2-T electromagnet. The performance analysis and engineering design of the flow path are described as well as the parameter measurements and flow diagnostics planned for the initial series of test runs.

MAPA: an interactive accelerator design code with GUI

NASA Astrophysics Data System (ADS)

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

1999-06-01

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

Diagnosis of Acceleration, Reconnection, Turbulence, and Heating

NASA Astrophysics Data System (ADS)

Dufor, Mikal T.; Jemiolo, Andrew J.; Keesee, Amy; Cassak, Paul; Tu, Weichao; Scime, Earl E.

2017-10-01

The DARTH (Diagnosis of Acceleration, Reconnection, Turbulence, and Heating) experiment is an intermediate-scale, experimental facility designed to study magnetic reconnection at and below the kinetic scale of ions and electrons. The experiment will have non-perturbative diagnostics with high temporal and three-dimensional spatial resolution, giving it the capability to investigate kinetic-scale physics. Of specific scientific interest are particle acceleration, plasma heating, turbulence and energy dissipation during reconnection. Here we will describe the magnetic field system and the two plasma guns used to create flux ropes that then merge through magnetic reconnection. We will also describe the key diagnostic systems: laser induced fluorescence (LIF) for ion vdf measurements, a 300 GHz microwave scattering system for sub-mm wavelength fluctuation measurements and a Thomson scattering laser for electron vdf measurements. The vacuum chamber is designed to provide unparalleled access for these particle diagnostics. The scientific goals of DARTH are to examine particle acceleration and heating during, the role of three-dimensional instabilities during reconnection, how reconnection ceases, and the role of impurities and asymmetries in reconnection. This work was supported by the by the O'Brien Energy Research Fund.

MeRHIC - staging approach to eRHIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ptitsyn,V.; Beebe-Wang, J.; Ben-Zvi, I.

Design of a medium energy electron-ion collider (MeRHIC) is under development at the Collider-Accelerator Department at BNL. The design envisions construction of a 4 GeV electron accelerator in a local area inside and near the RHIC tunnel. Electrons will be produced by a polarized electron source and accelerated in energy recovery linacs. Collisions of the electron beam with 100 GeV/u heavy ions or with 250 GeV polarized protons will be arranged in the existing IP2 interaction region of RHIC. The luminosity of electron-proton collisions at the 10{sup 32} cm{sup -2}s{sup -1} level will be achieved with 50 mA CW electronmore » current and presently available proton beam parameters. Efficient proton beam cooling at collision energy may bring the luminosity to 10{sup 33} cm{sup -2}s{sup -1}. An important feature of MeRHIC is that it serves as a first stage of eRHIC, a future electron-ion collider at BNL with both higher luminosity and energy reach. The majority of MeRHIC accelerator components will be used in eRHIC.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, A.; Barnard, J. J.; Cohen, R. H.

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,more » 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.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, A; Barnard, J J; Cohen, R H

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 Testmore » 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.« less

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.