WorldWideScience

Sample records for ground acceleration pga

  1. Earthquake hazard zonation using peak ground acceleration (PGA) approach

    International Nuclear Information System (INIS)

    Irwansyah, E; Winarko, E; Rasjid, Z E; Bekti, R D

    2013-01-01

    The objective of this research is to develop seismic hazard area zones in the building infrastructure of the Banda Aceh City Indonesia using peak ground acceleration (PGA) measured using global and local attenuation function. PGA is calculated using attenuation function that describes the correlation between the local ground movement intensity the earthquake magnitude and the distance from the earthquake's epicentre. The data used comes from the earthquake damage catalogue available from the Indonesia meteorology, climatology and geophysics agency (BMKG) with range from year 1973 – 2011. The research methodology consists of six steps, which is developing the grid, calculation of the distance from the epicentre to the centroid of the grid, calculation of PGA values, developing the computer application, plotting the PGA values to the centroid grid, and developing the earthquake hazard zones using kriging algorithm. The conclusion of this research is that the global attenuation function that was developed by [20] can be applied to calculate the PGA values in the city of Banda Aceh. Banda Aceh city in micro scale can be divided into three hazard zones which is low hazard zone with PGA value of 0.8767 gals up to 0.8780 gals, medium hazard zone with PGA values of 0.8781 up to 0.8793 gals and high hazard zone with PGA values of 0.8794 up to 0.8806 gals.

  2. Prediction of spectral acceleration response ordinates based on PGA attenuation

    Science.gov (United States)

    Graizer, V.; Kalkan, E.

    2009-01-01

    Developed herein is a new peak ground acceleration (PGA)-based predictive model for 5% damped pseudospectral acceleration (SA) ordinates of free-field horizontal component of ground motion from shallow-crustal earthquakes. The predictive model of ground motion spectral shape (i.e., normalized spectrum) is generated as a continuous function of few parameters. The proposed model eliminates the classical exhausted matrix of estimator coefficients, and provides significant ease in its implementation. It is structured on the Next Generation Attenuation (NGA) database with a number of additions from recent Californian events including 2003 San Simeon and 2004 Parkfield earthquakes. A unique feature of the model is its new functional form explicitly integrating PGA as a scaling factor. The spectral shape model is parameterized within an approximation function using moment magnitude, closest distance to the fault (fault distance) and VS30 (average shear-wave velocity in the upper 30 m) as independent variables. Mean values of its estimator coefficients were computed by fitting an approximation function to spectral shape of each record using robust nonlinear optimization. Proposed spectral shape model is independent of the PGA attenuation, allowing utilization of various PGA attenuation relations to estimate the response spectrum of earthquake recordings.

  3. gPGA: GPU Accelerated Population Genetics Analyses.

    Directory of Open Access Journals (Sweden)

    Chunbao Zhou

    Full Text Available The isolation with migration (IM model is important for studies in population genetics and phylogeography. IM program applies the IM model to genetic data drawn from a pair of closely related populations or species based on Markov chain Monte Carlo (MCMC simulations of gene genealogies. But computational burden of IM program has placed limits on its application.With strong computational power, Graphics Processing Unit (GPU has been widely used in many fields. In this article, we present an effective implementation of IM program on one GPU based on Compute Unified Device Architecture (CUDA, which we call gPGA.Compared with IM program, gPGA can achieve up to 52.30X speedup on one GPU. The evaluation results demonstrate that it allows datasets to be analyzed effectively and rapidly for research on divergence population genetics. The software is freely available with source code at https://github.com/chunbaozhou/gPGA.

  4. Empirical equations for the prediction of PGA and pseudo spectral accelerations using Iranian strong-motion data

    Science.gov (United States)

    Zafarani, H.; Luzi, Lucia; Lanzano, Giovanni; Soghrat, M. R.

    2018-01-01

    A recently compiled, comprehensive, and good-quality strong-motion database of the Iranian earthquakes has been used to develop local empirical equations for the prediction of peak ground acceleration (PGA) and 5%-damped pseudo-spectral accelerations (PSA) up to 4.0 s. The equations account for style of faulting and four site classes and use the horizontal distance from the surface projection of the rupture plane as a distance measure. The model predicts the geometric mean of horizontal components and the vertical-to-horizontal ratio. A total of 1551 free-field acceleration time histories recorded at distances of up to 200 km from 200 shallow earthquakes (depth < 30 km) with moment magnitudes ranging from Mw 4.0 to 7.3 are used to perform regression analysis using the random effects algorithm of Abrahamson and Youngs (Bull Seism Soc Am 82:505-510, 1992), which considers between-events as well as within-events errors. Due to the limited data used in the development of previous Iranian ground motion prediction equations (GMPEs) and strong trade-offs between different terms of GMPEs, it is likely that the previously determined models might have less precision on their coefficients in comparison to the current study. The richer database of the current study allows improving on prior works by considering additional variables that could not previously be adequately constrained. Here, a functional form used by Boore and Atkinson (Earthquake Spect 24:99-138, 2008) and Bindi et al. (Bull Seism Soc Am 9:1899-1920, 2011) has been adopted that allows accounting for the saturation of ground motions at close distances. A regression has been also performed for the V/H in order to retrieve vertical components by scaling horizontal spectra. In order to take into account epistemic uncertainty, the new model can be used along with other appropriate GMPEs through a logic tree framework for seismic hazard assessment in Iran and Middle East region.

  5. Grounding of SNS Accelerator Structure

    CERN Document Server

    Holik, Paul S

    2005-01-01

    Description of site general grounding network. RF grounding network enhancement underneath the klystron gallery building. Grounding network of the Ring Systems with ground breaks in the Ring Tunnel. Grounding and Bonding of R&D accelerator equipment. SNS Building lightning protection.

  6. Tunnel flexibility effect on the ground surface acceleration response

    Science.gov (United States)

    Baziar, Mohammad Hassan; Moghadam, Masoud Rabeti; Choo, Yun Wook; Kim, Dong-Soo

    2016-09-01

    Flexibility of underground structures relative to the surrounding medium, referred to as the flexibility ratio, is an important factor that influences their dynamic interaction. This study investigates the flexibility effect of a box-shaped subway tunnel, resting directly on bedrock, on the ground surface acceleration response using a numerical model verified against dynamic centrifuge test results. A comparison of the ground surface acceleration response for tunnel models with different flexibility ratios revealed that the tunnels with different flexibility ratios influence the acceleration response at the ground surface in different ways. Tunnels with lower flexibility ratios have higher acceleration responses at short periods, whereas tunnels with higher flexibility ratios have higher acceleration responses at longer periods. The effect of the flexibility ratio on ground surface acceleration is more prominent in the high range of frequencies. Furthermore, as the flexibility ratio of the tunnel system increases, the acceleration response moves away from the free field response and shifts towards the longer periods. Therefore, the flexibility ratio of the underground tunnels influences the peak ground acceleration (PGA) at the ground surface, and may need to be considered in the seismic zonation of urban areas.

  7. Sensitivity of seismic hazard to various parameters and correlations for peak ground acceleration

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Kushwaha, H.S.

    1998-10-01

    The design basis ground motion of a site is generally specified in terms of the peak ground acceleration (PGA), ground motion response spectrum and time history. The probability of exceedence of the design level PGA is one of the factors to quantify the seismic risk at the given site. The present paper extends the work of Cornell to consider an aerial source model and a more general form of the correlation for PGA to evaluate the seismic hazard. It is further recognised that the predicted seismic hazard can vary with various parameters involved. Numerical results have been presented to show this variability. These results will help to determine the seismic hazard at a given site and the associated uncertainties. (author)

  8. Seismic Hazard Analysis based on Earthquake Vulnerability and Peak Ground Acceleration using Microseismic Method at Universitas Negeri Semarang

    Science.gov (United States)

    Sulistiawan, H.; Supriyadi; Yulianti, I.

    2017-02-01

    Microseismic is a harmonic vibration of land that occurs continuously at a low frequency. The characteristics of microseismic represents the characteristics of the soil layer based on the value of its natural frequency. This paper presents the analysis of seismic hazard at Universitas Negeri Semarang using microseismic method. The data acquisition was done at 20 points with distance between points 300 m by using three component’s seismometer. The data was processed using Horizontal to Vertical Spectral Ratio (HVSR) method to obtain the natural frequency and amplification value. The value of the natural frequency and amplification used to determine the value of the earthquake vulnerability and peak ground acceleration (PGA). The result shows then the earthquake vulnerability value range from 0.2 to 7.5, while the value of the average peak ground acceleration (PGA) is in the range 10-24 gal. Therefore, the average peak ground acceleration equal to earthquake intensity IV MMI scale.

  9. Bayesian hierarchical model for variations in earthquake peak ground acceleration within small-aperture arrays

    KAUST Repository

    Rahpeyma, Sahar; Halldorsson, Benedikt; Hrafnkelsson, Birgir; Jonsson, Sigurjon

    2018-01-01

    Knowledge of the characteristics of earthquake ground motion is fundamental for earthquake hazard assessments. Over small distances, relative to the source–site distance, where uniform site conditions are expected, the ground motion variability is also expected to be insignificant. However, despite being located on what has been characterized as a uniform lava‐rock site condition, considerable peak ground acceleration (PGA) variations were observed on stations of a small‐aperture array (covering approximately 1 km2) of accelerographs in Southwest Iceland during the Ölfus earthquake of magnitude 6.3 on May 29, 2008 and its sequence of aftershocks. We propose a novel Bayesian hierarchical model for the PGA variations accounting separately for earthquake event effects, station effects, and event‐station effects. An efficient posterior inference scheme based on Markov chain Monte Carlo (MCMC) simulations is proposed for the new model. The variance of the station effect is certainly different from zero according to the posterior density, indicating that individual station effects are different from one another. The Bayesian hierarchical model thus captures the observed PGA variations and quantifies to what extent the source and recording sites contribute to the overall variation in ground motions over relatively small distances on the lava‐rock site condition.

  10. Bayesian hierarchical model for variations in earthquake peak ground acceleration within small-aperture arrays

    KAUST Repository

    Rahpeyma, Sahar

    2018-04-17

    Knowledge of the characteristics of earthquake ground motion is fundamental for earthquake hazard assessments. Over small distances, relative to the source–site distance, where uniform site conditions are expected, the ground motion variability is also expected to be insignificant. However, despite being located on what has been characterized as a uniform lava‐rock site condition, considerable peak ground acceleration (PGA) variations were observed on stations of a small‐aperture array (covering approximately 1 km2) of accelerographs in Southwest Iceland during the Ölfus earthquake of magnitude 6.3 on May 29, 2008 and its sequence of aftershocks. We propose a novel Bayesian hierarchical model for the PGA variations accounting separately for earthquake event effects, station effects, and event‐station effects. An efficient posterior inference scheme based on Markov chain Monte Carlo (MCMC) simulations is proposed for the new model. The variance of the station effect is certainly different from zero according to the posterior density, indicating that individual station effects are different from one another. The Bayesian hierarchical model thus captures the observed PGA variations and quantifies to what extent the source and recording sites contribute to the overall variation in ground motions over relatively small distances on the lava‐rock site condition.

  11. Grounding and shielding in the accelerator environment

    International Nuclear Information System (INIS)

    Kerns, Q.

    1991-01-01

    Everyday features of the accelerator environment include long cable runs, high power and low level equipment sharing building space, stray electromagnetic fields and ground voltage differences between the sending and receiving ends of an installation. This paper pictures some Fermilab installations chosen to highlight significant features and presents practices, test methods and equipment that have been helpful in achieving successful shielding. Throughout the report are numbered statements aimed at summarizing good practices and avoiding pitfalls

  12. Commissioning of the Ground Test Accelerator RFQ

    International Nuclear Information System (INIS)

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Connolly, R.; Garnett, R.; Gilpatrick, J.D.; Guy, F.W.; Ingalls, W.B.; Little, C.; Lohson, R.A.; Lloyd, S.; Neuschaefer, G.; Power, J.; Saadatmand, K.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H - beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 key H - injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2βγ Drift Tube Linac (DTL-1) module, the 8.7 MeV 2βγ DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the RFQ beam experiments will be presented along with comparisons to simulations

  13. Commissioning of the ground test accelerator RFQ

    International Nuclear Information System (INIS)

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Garnott, R.; Gilpatrick, J.D.; Guy, F.W.; Ingalls, W.B.; Little, C.; Lohsen, R.A.; Lloyd, S.; Neuschaefer, G.; Power, J.; Sandoval, D.P.; Saadatmand, K.; Stevens, R.R.Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H - beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on line. The commissioning stages are the 35-keV H - injector, the 2.5-MeV radio-frequency quadrupole (RFQ), the intertank matching section (IMS), the 3.2-MeV first 2-βλ drift tube linac (DTL-1) module, the 8.7-MeV 2-βλDTL (modules 1-5), and the 24-MeV GTA (all 10 DTL modules). Commissioning results from the RFQ beam experiments are presented along with comparisons with simulations. (Author) 8 refs., 9 figs

  14. Ground acceleration in a nuclear power plant

    International Nuclear Information System (INIS)

    Pena G, P.; Balcazar, M.; Vega R, E.

    2015-09-01

    A methodology that adopts the recommendations of international organizations for determining the ground acceleration at a nuclear power plant is outlined. Systematic presented here emphasizes the type of geological, geophysical and geotechnical studies in different areas of influence, culminating in assessments of Design Basis earthquake and the earthquake Operating Base. The methodology indicates that in regional areas where the site of the nuclear power plant is located, failures are identified in geological structures, and seismic histories of the region are documented. In the area of detail geophysical tools to generate effects to determine subsurface propagation velocities and spectra of the induced seismic waves are used. The mechanical analysis of drill cores allows estimating the efforts that generate and earthquake postulate. Studies show that the magnitude of the Fukushima earthquake, did not affect the integrity of nuclear power plants due to the rocky settlement found. (Author)

  15. Estimation of historical earthquake intensities and intensity-PGA relationship for wooden house damages

    International Nuclear Information System (INIS)

    Choi, In-Kil; Seo, Jeong-Moon

    2002-01-01

    A series of tests and dynamic analyses on Korean traditional wooden houses was performed for the intensity estimation of the typical large historical earthquake records. Static and cyclic lateral load tests on the wooden frames were performed to assess the lateral load capacity of wooden frames. The shaking table tests on two 1:4 scaled models of a Korean ancient commoner's house made of fresh pine lumber were performed. Typical earthquake time histories recorded on soil and rock sites were used as input for the tests. The prototypical wooden house was analyzed for multiple time histories which match Ohsaki's ground response spectra. Seismic analyses comprise the aging of lumber and different soil condition. The relationship between the earthquake intensity and the peak ground acceleration (PGA) is proposed for the wooden house damages based on the results of this study. The intensity of major Korean historical earthquake records related with house collapses was quantitatively estimated to be MM VIII

  16. Ground test accelerator control system software

    International Nuclear Information System (INIS)

    Burczyk, L.; Dalesio, R.; Dingler, R.; Hill, J.; Howell, J.A.; Kerstiens, D.; King, R.; Kozubal, A.; Little, C.; Martz, V.; Rothrock, R.; Sutton, J.

    1988-01-01

    This paper reports on the GTA control system that provides an environment in which the automation of a state-of-the-art accelerator can be developed. It makes use of commercially available computers, workstations, computer networks, industrial 110 equipment, and software. This system has built-in supervisory control (like most accelerator control systems), tools to support continuous control (like the process control industry), and sequential control for automatic start-up and fault recovery (like few other accelerator control systems). Several software tools support these levels of control: a real-time operating system (VxWorks) with a real-time kernel (VRTX), a configuration database, a sequencer, and a graphics editor. VxWorks supports multitasking, fast context-switching, and preemptive scheduling. VxWorks/VRTX is a network-based development environment specifically designed to work in partnership with the UNIX operating system. A data base provides the interface to the accelerator components. It consists of a run time library and a database configuration and editing tool. A sequencer initiates and controls the operation of all sequence programs (expressed as state programs). A graphics editor gives the user the ability to create color graphic displays showing the state of the machine in either text or graphics form

  17. Ground motions and its effects in accelerator design

    International Nuclear Information System (INIS)

    Fischer, G.E.

    1984-07-01

    This lecture includes a discussion of types of motion, frequencies of interest, measurements at SLAC, some general comments regarding local sources of ground motion at SLAC, and steps that can be taken to minimize the effects of ground motion on accelerators

  18. Ground motion and its effects in accelerator design

    International Nuclear Information System (INIS)

    Fischer, G.E.

    1985-07-01

    The effects of ground motion on accelerator design are discussed. The limitations on performance are discussed for various categories of motion. For example, effects due to ground settlement, tides, seismic disturbances and man-induced disturbances are included in this discussion. 42 figs., 7 tabs

  19. Ground motion: An introduction for accelerator builders

    International Nuclear Information System (INIS)

    Fischer, G.E.

    1992-02-01

    In this seminar we will review some of the characteristics of the major classes of ground motion in order to determine whether their effects must be considered or place fundamental limits on the sitting and/or design of modern storage rings and linear colliders. The classes discussed range in frequency content from tidal deformation and tectonic motions through earthquakes and microseisms. Countermeasures currently available are briefly discussed

  20. Ground motion: An introduction for accelerator builders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1992-02-01

    In this seminar we will review some of the characteristics of the major classes of ground motion in order to determine whether their effects must be considered or place fundamental limits on the sitting and/or design of modern storage rings and linear colliders. The classes discussed range in frequency content from tidal deformation and tectonic motions through earthquakes and microseisms. Countermeasures currently available are briefly discussed.

  1. A fiber Bragg grating acceleration sensor for ground surveillance

    Science.gov (United States)

    Jiang, Shaodong; Zhang, Faxiang; Lv, Jingsheng; Ni, Jiasheng; Wang, Chang

    2017-10-01

    Ground surveillance system is a kind of intelligent monitoring equipment for detecting and tracking the ground target. This paper presents a fiber Bragg grating (FBG) acceleration sensor for ground surveillance, which has the characteristics of no power supply, anti-electromagnetic interference, easy large-scale networking, and small size. Which make it able to achieve the advantage of the ground surveillance system while avoiding the shortcoming of the electric sensing. The sensor has a double cantilever beam structure with a sensitivity of 1000 pm/g. Field experiment has been carried out on a flood beach to examine the sensor performance. The result shows that the detection distance on the walking of personnel reaches 70m, and the detection distance on the ordinary motor vehicle reaches 200m. The performance of the FBG sensor can satisfy the actual needs of the ground surveillance system.

  2. Exceptional Ground Accelerations and Velocities Caused by Earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, John

    2008-01-17

    This project aims to understand the characteristics of the free-field strong-motion records that have yielded the 100 largest peak accelerations and the 100 largest peak velocities recorded to date. The peak is defined as the maximum magnitude of the acceleration or velocity vector during the strong shaking. This compilation includes 35 records with peak acceleration greater than gravity, and 41 records with peak velocities greater than 100 cm/s. The results represent an estimated 150,000 instrument-years of strong-motion recordings. The mean horizontal acceleration or velocity, as used for the NGA ground motion models, is typically 0.76 times the magnitude of this vector peak. Accelerations in the top 100 come from earthquakes as small as magnitude 5, while velocities in the top 100 all come from earthquakes with magnitude 6 or larger. Records are dominated by crustal earthquakes with thrust, oblique-thrust, or strike-slip mechanisms. Normal faulting mechanisms in crustal earthquakes constitute under 5% of the records in the databases searched, and an even smaller percentage of the exceptional records. All NEHRP site categories have contributed exceptional records, in proportions similar to the extent that they are represented in the larger database.

  3. Beam loading and cavity compensation for the ground test accelerator

    International Nuclear Information System (INIS)

    Jachim, S.P.; Natter, E.F.

    1989-01-01

    The Ground Test Accelerator (GTA) will be a heavily beam-loaded H/sup minus/ linac with tight tolerances on accelerating field parameters. The methods used in modeling the effects of beam loading in this machine are described. The response of the cavity to both beam and radio-frequency (RF) drive stimulus is derived, including the effects of cavity detuning. This derivation is not restricted to a small-signal approximation. An analytical method for synthesizing a predistortion network that decouples the amplitude and phase responses of the cavity is also outlined. Simulation of performance, including beam loading, is achieved through use of a control system analysis software package. A straightforward method is presented for extrapolating this work to model large coupled structures with closely spaced parasitic modes. Results to date have enabled the RF control system designs for GTA to be optimized and have given insight into their operation. 6 refs., 10 figs

  4. Commissioning of the Ground Test Accelerator Intertank Matching Section

    International Nuclear Information System (INIS)

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Ingalls, W.B.; Kersteins, D.; Little, C.; Lohsen, R.A.; Lysenko, W.P.; Mottershead, C.T.; Power, J.; Rusthoi, D.P.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H - beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 keV H - injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2βγ Drift Tube Linac (DTL-1) module, the 8.7 MeV 2βγ DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the IMS beam experiments will be presented

  5. RFLP's for the human pepsinogen A haplotypes (PGA)

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, R T; Boudi, F B; Bell, G I

    1988-10-11

    PGA 101 is a 1340 bp cDNA clone containing exons 1-9 of the predicted human pepsinogen A coding sequence. Two distinct polymorphisms are detected with EcoRI and Bg1 II. Analysis with these enzymes provides for discrimination of the PGA haplotypes A, B, and C containing three, two and one PGA genes respectively. The PGA complex is located at 11q13. Mendelian inheritance was demonstrated in 20 families.

  6. Lessons learned on the Ground Test Accelerator control system

    International Nuclear Information System (INIS)

    Kozubal, A.J.; Weiss, R.E.

    1994-01-01

    When we initiated the control system design for the Ground Test Accelerator (GTA), we envisioned a system that would be flexible enough to handle the changing requirements of an experimental project. This control system would use a developers' toolkit to reduce the cost and time to develop applications for GTA, and through the use of open standards, the system would accommodate unforeseen requirements as they arose. Furthermore, we would attempt to demonstrate on GTA a level of automation far beyond that achieved by existing accelerator control systems. How well did we achieve these goals? What were the stumbling blocks to deploying the control system, and what assumptions did we make about requirements that turned out to be incorrect? In this paper we look at the process of developing a control system that evolved into what is now the ''Experimental Physics and Industrial Control System'' (EPICS). Also, we assess the impact of this system on the GTA project, as well as the impact of GTA on EPICS. The lessons learned on GTA will be valuable for future projects

  7. Earthquake Ground Motion Measures for Seismic Response Evaluation of Structures

    Energy Technology Data Exchange (ETDEWEB)

    Cho, In-Kil; Ahn, Seong-Moon; Choun, Young-Sun; Seo, Jeong-Moon

    2007-03-15

    This study used the assessment results of failure criteria - base shear, story drift, top acceleration and top displacement - for a PSC containment building subjected to 30 sets of near-fault ground motions to evaluate the earthquake ground motion intensity measures. Seven intensity measures, peak ground acceleration(PGA), peak ground velocity(PGV), spectral acceleration(Sa), velocity(Sv), spectrum intensity for acceleration(SIa), velocity(SIv) and displacement(SId), were used to represent alternative ground motion. The regression analyses of the failure criteria for a PSC containment building were carried out to evaluate a proper intensity measure by using two regression models and seven ground motion parameters. The regression analysis results demonstrate the correlation coefficients of the failure criteria in terms of the candidate IM. From the results, spectral acceleration(Sa) is estimated as the best parameter for a evaluation of the structural safety for a seismic PSA.

  8. Summary of the GK15 ground‐motion prediction equation for horizontal PGA and 5% damped PSA from shallow crustal continental earthquakes

    Science.gov (United States)

    Graizer, Vladimir;; Kalkan, Erol

    2016-01-01

    We present a revised ground‐motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration (PGA) and 5% damped pseudospectral acceleration (PSA) response ordinates of the horizontal component of randomly oriented ground motions to be used for seismic‐hazard analyses and engineering applications. This GMPE is derived from the expanded Next Generation Attenuation (NGA)‐West 1 database (see Data and Resources; Chiou et al., 2008). The revised model includes an anelastic attenuation term as a function of quality factor (Q0) to capture regional differences in far‐source (beyond 150 km) attenuation, and a new frequency‐dependent sedimentary‐basin scaling term as a function of depth to the 1.5  km/s shear‐wave velocity isosurface to improve ground‐motion predictions at sites located on deep sedimentary basins. The new Graizer–Kalkan 2015 (GK15) model, developed to be simple, is applicable for the western United States and other similar shallow crustal continental regions in active tectonic environments for earthquakes with moment magnitudes (M) 5.0–8.0, distances 0–250 km, average shear‐wave velocities in the upper 30 m (VS30) 200–1300  m/s, and spectral periods (T) 0.01–5 s. Our aleatory variability model captures interevent (between‐event) variability, which decreases with magnitude and increases with distance. The mixed‐effect residuals analysis reveals that the GK15 has no trend with respect to the independent predictor parameters. Compared to our 2007–2009 GMPE, the PGA values are very similar, whereas spectral ordinates predicted are larger at T<0.2  s and they are smaller at longer periods.

  9. Relationships between ground reaction impulse and sprint acceleration performance in team sport athletes.

    Science.gov (United States)

    Kawamori, Naoki; Nosaka, Kazunori; Newton, Robert U

    2013-03-01

    Large horizontal acceleration in short sprints is a critical performance parameter for many team sport athletes. It is often stated that producing large horizontal impulse at each ground contact is essential for high short sprint performance, but the optimal pattern of horizontal and vertical impulses is not well understood, especially when the sprints are initiated from a standing start. This study was an investigation of the relationships between ground reaction impulses and sprint acceleration performance from a standing start in team sport athletes. Thirty physically active young men with team sport background performed 10-m sprint from a standing start, whereas sprint time and ground reaction forces were recorded during the first ground contact and at 8 m from the start. Associations between sprint time and ground reaction impulses (normalized to body mass) were determined by a Pearson's correlation coefficient (r) analysis. The 10-m sprint time was significantly (p < 0.01) correlated with net horizontal impulse (r = -0.52) and propulsive impulse (r = -0.66) measured at 8 m from the start. No significant correlations were found between sprint time and impulses recorded during the first ground contact after the start. These results suggest that applying ground reaction impulse in a more horizontal direction is important for sprint acceleration from a standing start. This is consistent with the hypothesis of training to increase net horizontal impulse production using sled towing or using elastic resistance devices, which needs to be validated by future longitudinal training studies.

  10. Mitigation of ground motion effects in linear accelerators via feed-forward control

    Directory of Open Access Journals (Sweden)

    J. Pfingstner

    2014-12-01

    Full Text Available Ground motion is a severe problem for many particle accelerators, since it excites beam oscillations, which decrease the beam quality and create beam-beam offset (at colliders. Orbit feedback systems can only compensate ground motion effects at frequencies significantly smaller than the beam repetition rate. In linear colliders, where the repetition rate is low, additional counter measures have to be put in place. For this reason, a ground motion mitigation method based on feed-forward control is presented in this paper. It has several advantages compared to other techniques (stabilization systems and intratrain feedback systems such as cost reduction and potential performance improvement. An analytical model is presented that allows the derivation of hardware specification and performance estimates for a specific accelerator and ground motion model. At the Accelerator Test Facility (ATF2, ground motion sensors have been installed to verify the feasibility of important parts of the mitigation strategy. In experimental studies, it has been shown that beam excitations due to ground motion can be predicted from ground motion measurements on a pulse-to-pulse basis. Correlations of up to 80% between the estimated and measured orbit jitter have been observed. Additionally, an orbit jitter source was identified and has been removed, which halved the orbit jitter power at ATF2 and shows that the feed-forward scheme is also very useful for the detection of installation issues. We believe that the presented mitigation method has the potential to reduce costs and improve the performance of linear colliders and potentially other linear accelerators.

  11. Increasing Minority Golf Participation Through PGA Education Initiatives

    Directory of Open Access Journals (Sweden)

    Jill Fjelstul

    2011-07-01

    Full Text Available The article provides a report on the successful acquisition of the Professional Golfers Association of America (PGA golf management university program by the University of Maryland, Eastern Shore (UMES. The PGA’s accredited program is housed at 20 universities with UMES being the first predominantly Black college to offer the coveted program. The article provides interview excerpts on the process undertaken by UMES. The article also identifies initiatives by programs and associations to increase minority golf participation.

  12. Ground-motion prediction from tremor

    Science.gov (United States)

    Baltay, Annemarie S.; Beroza, Gregory C.

    2013-01-01

    The widespread occurrence of tremor, coupled with its frequency content and location, provides an exceptional opportunity to test and improve strong ground-motion attenuation relations for subduction zones. We characterize the amplitude of thousands of individual 5 min tremor events in Cascadia during three episodic tremor and slip events to constrain the distance decay of peak ground acceleration (PGA) and peak ground velocity (PGV). We determine the anelastic attenuation parameter for ground-motion prediction equations (GMPEs) to a distance of 150 km, which is sufficient to place important constraints on ground-motion decay. Tremor PGA and PGV show a distance decay that is similar to subduction-zone-specific GMPEs developed from both data and simulations; however, the massive amount of data present in the tremor observations should allow us to refine distance-amplitude attenuation relationships for use in hazard maps, and to search for regional variations and intrasubduction zone differences in ground-motion attenuation.

  13. Ground Motion Prediction Models for Caucasus Region

    Science.gov (United States)

    Jorjiashvili, Nato; Godoladze, Tea; Tvaradze, Nino; Tumanova, Nino

    2016-04-01

    Ground motion prediction models (GMPMs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration or spectral acceleration because this parameter gives useful information for Seismic Hazard Assessment. Since 2003 development of Georgian Digital Seismic Network has started. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models is obtained by classical, statistical way, regression analysis. In this study site ground conditions are additionally considered because the same earthquake recorded at the same distance may cause different damage according to ground conditions. Empirical ground-motion prediction models (GMPMs) require adjustment to make them appropriate for site-specific scenarios. However, the process of making such adjustments remains a challenge. This work presents a holistic framework for the development of a peak ground acceleration (PGA) or spectral acceleration (SA) GMPE that is easily adjustable to different seismological conditions and does not suffer from the practical problems associated with adjustments in the response spectral domain.

  14. On higher ground: how well can dynamic body acceleration determine speed in variable terrain?

    Directory of Open Access Journals (Sweden)

    Owen R Bidder

    Full Text Available INTRODUCTION: Animal travel speed is an ecologically significant parameter, with implications for the study of energetics and animal behaviour. It is also necessary for the calculation of animal paths by dead-reckoning. Dead-reckoning uses heading and speed to calculate an animal's path through its environment on a fine scale. It is often used in aquatic environments, where transmission telemetry is difficult. However, its adoption for tracking terrestrial animals is limited by our ability to measure speed accurately on a fine scale. Recently, tri-axial accelerometers have shown promise for estimating speed, but their accuracy appears affected by changes in substrate and surface gradients. The purpose of the present study was to evaluate four metrics of acceleration; Overall dynamic body acceleration (ODBA, vectorial dynamic body acceleration (VDBA, acceleration peak frequency and acceleration peak amplitude, as proxies for speed over hard, soft and inclined surfaces, using humans as a model species. RESULTS: A general linear model (GLM showed a significant difference in the relationships between the metrics and speed depending on substrate or surface gradient. When the data from all surface types were considered together, VeDBA had the highest coefficient of determination. CONCLUSIONS: All of the metrics showed some variation in their relationship with speed according to the surface type. This indicates that changes in the substrate or surface gradient during locomotion by animals would produce errors in speed estimates, and also in dead-reckoned tracks if they were calculated from speeds based entirely on a priori calibrations. However, we describe a method by which the relationship between acceleration metrics and speed can be corrected ad hoc, until tracks accord with periodic ground truthed positions, obtained via a secondary means (e.g. VHF or GPS telemetry. In this way, dead-reckoning provides a means to obtain fine scale movement data

  15. The Temporal Sensitivity of Enforced Accelerated Work Pace: A grounded theory building approach

    Directory of Open Access Journals (Sweden)

    Graham John James Kenealy, BA (Hons, Ph.D. Candidate

    Full Text Available This research explores how a large national UK government organisation copes with radical structural change over time and provides an insight into the temporal effects of ‘Enforced Accelerated Work Pace’ on behaviour and receptivity within an organisational context. The stages of ‘Acceptance’, ‘Reaction’ and‘Withdrawal’ capture the essence of the ‘Coping Reflex Actions relating to Enforced Accelerated Work Pace’, all sensitive to the effects of time. ‘Temporal Sensitivity’; the duration of the changes to work patterns played a large part in the behavioural responses. The underlying logic of this research is grounded theory building, a general method that works well with qualitative data collection approaches and involves inducting insights from field based, case data (Glaser, 1998. A methodology discovered and developed by Glaser and Strauss (1967, negating all others.

  16. Ground reaction force estimates from ActiGraph GT3X+ hip accelerations.

    Directory of Open Access Journals (Sweden)

    Jennifer M Neugebauer

    Full Text Available Simple methods to quantify ground reaction forces (GRFs outside a laboratory setting are needed to understand daily loading sustained by the body. Here, we present methods to estimate peak vertical GRF (pGRFvert and peak braking GRF (pGRFbrake in adults using raw hip activity monitor (AM acceleration data. The purpose of this study was to develop a statistically based model to estimate pGRFvert and pGRFbrake during walking and running from ActiGraph GT3X+ AM acceleration data. 19 males and 20 females (age 21.2 ± 1.3 years, height 1.73 ± 0.12 m, mass 67.6 ± 11.5 kg wore an ActiGraph GT3X+ AM over their right hip. Six walking and six running trials (0.95-2.19 and 2.20-4.10 m/s, respectively were completed. Average of the peak vertical and anterior/posterior AM acceleration (ACCvert and ACCbrake, respectively and pGRFvert and pGRFbrake during the stance phase of gait were determined. Thirty randomly selected subjects served as the training dataset to develop generalized equations to predict pGRFvert and pGRFbrake. Using a holdout approach, the remaining 9 subjects were used to test the accuracy of the models. Generalized equations to predict pGRFvert and pGRFbrake included ACCvert and ACCbrake, respectively, mass, type of locomotion (walk or run, and type of locomotion acceleration interaction. The average absolute percent differences between actual and predicted pGRFvert and pGRFbrake were 8.3% and 17.8%, respectively, when the models were applied to the test dataset. Repeated measures generalized regression equations were developed to predict pGRFvert and pGRFbrake from ActiGraph GT3X+ AM acceleration for young adults walking and running. These equations provide a means to estimate GRFs without a force plate.

  17. Seismic microzonation on peak ground acceleration for Sapporo area; Sapporo chiiki no seismic microzonation

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, S [Muroran Institute of Technology, Hokkaido (Japan); Vuetibau, L

    1997-10-22

    With an objective for use as fundamental information and data for measures to prevent disasters from regional earthquakes, microzonation was carried out on the Sapporo area. The present study has conducted comparisons and discussions on frequency distributions of maximum surface acceleration in the Sapporo area and the previously analyzed Muroran, Tomakomai and Obihiro areas. In the Muroran area, the frequency is distributed widely from 50 to 220 gal, while it is distributed narrowly from 110 to 170 gal in the Tomakomai area, and 90 to 160 gal in the Obihiro area. Such distributions have been formed possibly because the Muroran area has different kinds of grounds exist with hills and lowlands tangled, while the Tomakomai and Obihiro areas have nearly the same ground conditions with the topography being flat and the areas being located in an alluvial plain with soft Quaternary bed having been grown to a great thickness. The Sapporo area showed distribution close to that in the Muroran area. The maximum surface acceleration may vary even in the same mesh. This indicates that more detailed seismic microzonation is necessary to establish more effective means to prevent disasters from earthquakes. 10 refs., 4 figs., 1 tab.

  18. Feasibility study of a nonequilibrium MHD accelerator concept for hypersonic propulsion ground testing

    International Nuclear Information System (INIS)

    Lee, Ying-Ming; Simmons, G.A.; Nelson, G.L.

    1995-01-01

    A National Aeronautics and Space Administration (NASA) funded research study to evaluate the feasibility of using magnetohydrodynamic (MHD) body force accelerators to produce true air simulation for hypersonic propulsion ground testing is discussed in this paper. Testing over the airbreathing portion of a transatmospheric vehicle (TAV) hypersonic flight regime will require high quality air simulation for actual flight conditions behind a bow shock wave (forebody, pre-inlet region) for flight velocities up to Mach 16 and perhaps beyond. Material limits and chemical dissociation at high temperature limit the simulated flight Mach numbers in conventional facilities to less than Mach 12 for continuous and semi-continuous testing and less than Mach 7 for applications requiring true air chemistry. By adding kinetic energy directly to the flow, MHD accelerators avoid the high temperatures and pressures required in the reservoir region of conventional expansion facilities, allowing MHD to produce true flight conditions in flight regimes impossible with conventional facilities. The present study is intended to resolve some of the critical technical issues related to the operation of MHD at high pressure. Funding has been provided only for the first phase of a three to four year feasibility study that would culminate in the demonstration of MHD acceleration under conditions required to produce true flight conditions behind a bow shock wave to flight Mach numbers of 16 or greater. MHD critical issues and a program plan to resolve these are discussed

  19. Lack of the PGA exopolysaccharide in Salmonella as an adaptive trait for survival in the host.

    Directory of Open Access Journals (Sweden)

    Maite Echeverz

    2017-05-01

    Full Text Available Many bacteria build biofilm matrices using a conserved exopolysaccharide named PGA or PNAG (poly-β-1,6-N-acetyl-D-glucosamine. Interestingly, while E. coli and other members of the family Enterobacteriaceae encode the pgaABCD operon responsible for PGA synthesis, Salmonella lacks it. The evolutionary force driving this difference remains to be determined. Here, we report that Salmonella lost the pgaABCD operon after the divergence of Salmonella and Citrobacter clades, and previous to the diversification of the currently sequenced Salmonella strains. Reconstitution of the PGA machinery endows Salmonella with the capacity to produce PGA in a cyclic dimeric GMP (c-di-GMP dependent manner. Outside the host, the PGA polysaccharide does not seem to provide any significant benefit to Salmonella: resistance against chlorine treatment, ultraviolet light irradiation, heavy metal stress and phage infection remained the same as in a strain producing cellulose, the main biofilm exopolysaccharide naturally produced by Salmonella. In contrast, PGA production proved to be deleterious to Salmonella survival inside the host, since it increased susceptibility to bile salts and oxidative stress, and hindered the capacity of S. Enteritidis to survive inside macrophages and to colonize extraintestinal organs, including the gallbladder. Altogether, our observations indicate that PGA is an antivirulence factor whose loss may have been a necessary event during Salmonella speciation to permit survival inside the host.

  20. Determination of 36Cl/Cl ratio in ground water using the accelerator mass spectrometry technique

    International Nuclear Information System (INIS)

    Sharma, Suman; Deodhar, A.S.; Saravana Kumar, U.; Surendran, P.; Shrivastava, A.; Gupta, A.K.; Nair, J.P.; Yadav, M.L.; Hemalatha, M.; Sparrow, H.; Mahata, K.; Thomas, R.G.; Bhagwat, P.V.; Kailas, S.; Kale, R.M.

    2009-01-01

    The Accelerator Mass Spectrometry (AMS) programme using the 14 MV Pelletron Accelerator at Mumbai has been initiated with major emphasis on the determination of 36 Cl in water samples, of interest to hydrology and environment. In order to carry out the AMS measurement, a beam chopper to cut down beam intensity by a factor of 20 has been developed and commissioned. A multi-anode gas -si detector has been built to separate 36 Cl from the interfering 36 S. A new TPS system has been procured to operate the machine in the GVM mode. Standard and blank samples from Prime lab, Purdue have been employed in these measurements to standardise the technique for 36 Cl/Cl ratio determination. The detector was calibrated using the stable 35,37 Cl ions. The background 36 Cl in the system has been measured using the blank sample from Purdue and it was estimated that the ratio of 36 Cl/Cl was of the order of 10 -13 in the present setup. Ground water samples collected from South India were converted to AgCl and put in the SNICS ion source for the AMS measurements. These ground water samples, with 14 C content estimated to be in the range of 1 to 4 pMC indicate that the samples may be more than 35,000 years old. Using the AMS technique we have determined the 36 Cl/Cl ratio values for these ground water samples. They are found to range between 2 to 5 x 10 -12 . Additional measurements are planned to determine the age of the water samples and to understand the reasons for the observed high values of 36 Cl in these samples. (author)

  1. Comparisons of PGA and INAA in the analyses of meteorite samples

    International Nuclear Information System (INIS)

    Wee Boon Siong; Ebihara, M.; Abdul Khalik Wood

    2010-01-01

    Prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA) are suitable methods for multi-elemental determinations in various samples. These two methods are complementary because PGA is capable of analyzing most major and minor elements in rock samples whereas INAA is more superior in determining minor and trace elements. Both PGA and INAA are essential for the study of rare samples such as meteorites because of non-destructivity and relatively being free from contaminations. Samples for PGA can be reused for INAA, which help to reduce the sample usage. This project aims to utilize PGA and INAA techniques for comparative study and apply them to meteorites. In this study, 11 meteorite samples received from the Meteorite Working Group of NASA were analyzed. The Allende meteorite powder was included as quality control material. Results from PGA and INAA for Allende showed good agreement with literature values, signifying the reliabilities of these two methods. Elements Al, Ca, Mg, Mn, Na and Ti were determined by both methods and their results are compared. Comparison of PGA and INAA data using linear regression analysis showed correlations coefficients r 2 > 0.90 for Al, Ca, Mn and Ti, 0.85 for Mg, and 0.38 for Na. The PGA results for Na using 472 keV were less accurate due to the interference from the broad B peak. Therefore, Na results from INAA method are preferred. For other elements (Al, Ca, Mg, Mn and Ti), PGA and INAA results can be used as cross-reference for consistency. The PGA and INAA techniques have been applied to meteorite samples and results are comparable to literature values compiled from previously analyzed meteorites. In summary, both PGA and INAA methods give reasonably good agreement and are indispensable in the study of meteorites. (author)

  2. RF System description for the ground test accelerator radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Regan, A.H.; Brittain, D.; Rees, D.E.; Ziomek, D.

    1992-01-01

    This paper describes the RF system being used to provide RF power and to control the cavity field for the ground test accelerator (GTA) radio-frequency quadrupole (RFQ). The RF system consists of a low-level RF (LLRF) control system, and RF Reference generation subsystem, and a tetrode as a high-power amplifier (HPA) that can deliver up to 300 kW of peak power to the RFQ cavity at a 2% duty factor. The LLRF control system implements in-phase and quadrature (I and Q) control to maintain the cavity field within tolerances of 0.5% in amplitude and 0.5 degrees in phase in the presence of beam-induced instabilities

  3. Rf system description for the ground test accelerator radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Regan, A.H.; Brittain, D.; Rees, D.E.; Ziomek, D.

    1992-01-01

    This paper describes the RF system being used to provide RF power and to control the cavity field used for the ground test accelerator (GTA) radio-frequency quadrupole (RFQ). The RF system consists of a low-level RF (LLRF) control system that uses a tetrode as a high-power amplifier (HPA) as part of its plant to deliver up to 300 kW of peak power to the RFQ at a 2% duty factor. The LLRF control system implements in-phase and quadrature (I ampersand Q) control to maintain the cavity field within tolerances of 0.5% in amplitude and 0.5 degrees in phase in the presence of beam-induced instabilities. This paper describes the identified components and presents measured performance data. The user interface with the systems is described, and cavity field measurements are included

  4. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-10-01

    This document is the first volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of an introduction, summary/conclusion, site description and assessment, description of facility, and description of operation.

  5. Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

    International Nuclear Information System (INIS)

    Wright, R.; Zander, M.; Brown, S.; Sandoval, D.; Gilpatrick, D.; Gibson, H.

    1992-01-01

    This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) is discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. (Author) (3 figs., 4 refs.)

  6. Ground acceleration in a nuclear power plant; Aceleracion del suelo en una central nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Pena G, P.; Balcazar, M.; Vega R, E., E-mail: pablo.pena@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2015-09-15

    A methodology that adopts the recommendations of international organizations for determining the ground acceleration at a nuclear power plant is outlined. Systematic presented here emphasizes the type of geological, geophysical and geotechnical studies in different areas of influence, culminating in assessments of Design Basis earthquake and the earthquake Operating Base. The methodology indicates that in regional areas where the site of the nuclear power plant is located, failures are identified in geological structures, and seismic histories of the region are documented. In the area of detail geophysical tools to generate effects to determine subsurface propagation velocities and spectra of the induced seismic waves are used. The mechanical analysis of drill cores allows estimating the efforts that generate and earthquake postulate. Studies show that the magnitude of the Fukushima earthquake, did not affect the integrity of nuclear power plants due to the rocky settlement found. (Author)

  7. Performance report on the ground test accelerator radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.

    1994-01-01

    The Ground Test Accelerator (GTA) uses a radio-frequency quadrupole (RFQ) to bunch and accelerate a 35 keV input beam to a final energy of 2.5 MeV. Most measured parameters of the GTA RFQ agreed with simulated predictions. The relative shape of the transmission versus the vane-voltage relationship and the Courant-Snyder (CS) parameters of the output beam's transverse and longitudinal phase spaces agreed well with predictions. However, the transmission of the RFQ was significantly lower than expected. Improved simulation studies included image charges and multipole effects in the RFQ. Most of the predicted properties of the RFQ, such as input matched-beam conditions and output-beam shapes were unaffected by these additional effects. However, the comparison of measured with predicted absolute values of transmitted beam was much improved by the inclusion of these effects in the simulations. The comparison implied a value for the input emittance that is consistent with measurements

  8. Validation of strong-motion stochastic model using observed ground motion records in north-east India

    Directory of Open Access Journals (Sweden)

    Dipok K. Bora

    2016-03-01

    Full Text Available We focused on validation of applicability of semi-empirical technique (spectral models and stochastic simulation for the estimation of ground-motion characteristics in the northeastern region (NER of India. In the present study, it is assumed that the point source approximation in far field is valid. The one-dimensional stochastic point source seismological model of Boore (1983 (Boore, DM. 1983. Stochastic simulation of high frequency ground motions based on seismological models of the radiated spectra. Bulletin of Seismological Society of America, 73, 1865–1894. is used for modelling the acceleration time histories. Total ground-motion records of 30 earthquakes of magnitudes lying between MW 4.2 and 6.2 in NER India from March 2008 to April 2013 are used for this study. We considered peak ground acceleration (PGA and pseudospectral acceleration (response spectrum amplitudes with 5% damping ratio at three fundamental natural periods, namely: 0.3, 1.0, and 3.0 s. The spectral models, which work well for PGA, overestimate the pseudospectral acceleration. It seems that there is a strong influence of local site amplification and crustal attenuation (kappa, which control spectral amplitudes at different frequencies. The results would allow analysing regional peculiarities of ground-motion excitation and propagation and updating seismic hazard assessment, both the probabilistic and deterministic approaches.

  9. Non uniform nature of recorded ground accelerations at dam foundation interface

    Energy Technology Data Exchange (ETDEWEB)

    Ghaemian, Mohsen; Gilani, Morteza Sohrabi [Sharif University of Technology, Tehran, (Iran, Islamic Republic of); Noorzad, Ali [Power and Water University of Technology, Tehran, (Iran, Islamic Republic of)

    2010-07-01

    The Karun III is a double curved concrete arch dam located in Iran which was used to investigate earthquake motions and dam responses. This paper presented the study of the Karun III dam foundation interface. Using an array of 15 accelerometers, two major events that occurred on 2007.11.20 and 2007.11.21 were recorded during dam operation with a PGA at crest of 0.312 g and 0.109.g respectively. A finite element model of Karun III dam was performed. The response of the Karun III dam during the 2007 earthquake was investigated using the NSAD-DRI program. It was found that the motion of the dam foundation interface is non-uniform. There is a time shift and amplification at the abutment compared to those at the base of the dam. The results showed that the spatially varying earthquake assumption is in good agreement with the recorded displacement of the dam.

  10. Mixed-field GCR Simulations for Radiobiological Research using Ground Based Accelerators

    Science.gov (United States)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20 percents accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  11. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-10-01

    This document is the second volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of failure modes and effects analysis; accident analysis; operational safety requirements; quality assurance program; ES&H management program; environmental, safety, and health systems critical to safety; summary of waste-management program; environmental monitoring program; facility expansion, decontamination, and decommissioning; summary of emergency response plan; summary plan for employee training; summary plan for operating procedures; glossary; and appendices A and B.

  12. Effect of hydroelastic coupling on the response of a nuclear reactor to ground acceleration

    International Nuclear Information System (INIS)

    Au-Yang, M.K.; Skinner, D.A.

    1977-01-01

    The dynamical characteristics of a nuclear reactor vessel and its internal components is affected by the coolant inside the vessel. Recent studies in flow-induced vibration of reactor internal components show that the effect of the entrapped coolant can be properly accounted for by adding a 'hydrodynamic mass' matrix to the physical mass of the fluid structure system. In the past few years, analytical expressions for this hydrodynamic mass matrix have been derived, usually under greatly simplifying assumptions on the geometry of the structure. Typical examples are slender-cylinder and simply-supported-cylinder assumptions. While expressions derived based on these assumptions can still bring out the general characteristics of hydroelastic coupling of structure, their application to seismic analysis of reactor components is limited because these structutres, even though generally cylindrical, are usually neither slender nor simply supported. This paper presents an anlytical and experimental study of the effects of hydroelastic coupling on the seismic response of a reactor vessel and its internal components. The hydrodynamic mass matrix for cylindrical shell structures with arbitrary D/l ratios. Two specific examples are included to illustrate the effect of hydroelastic coupling on the response of a PWR to ground acceleration. (Auth.)

  13. Estimation of peak ground accelerations for Mexican subduction zone earthquakes using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Silvia R; Romo, Miguel P; Mayoral, Juan M [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico)

    2007-01-15

    An extensive analysis of the strong ground motion Mexican data base was conducted using Soft Computing (SC) techniques. A Neural Network NN is used to estimate both orthogonal components of the horizontal (PGAh) and vertical (PGAv) peak ground accelerations measured at rock sites during Mexican subduction zone earthquakes. The work discusses the development, training, and testing of this neural model. Attenuation phenomenon was characterized in terms of magnitude, epicentral distance and focal depth. Neural approximators were used instead of traditional regression techniques due to their flexibility to deal with uncertainty and noise. NN predictions follow closely measured responses exhibiting forecasting capabilities better than those of most established attenuation relations for the Mexican subduction zone. Assessment of the NN, was also applied to subduction zones in Japan and North America. For the database used in this paper the NN and the-better-fitted- regression approach residuals are compared. [Spanish] Un analisis exhaustivo de la base de datos mexicana de sismos fuertes se llevo a cabo utilizando tecnicas de computo aproximado, SC (soft computing). En particular, una red neuronal, NN, es utilizada para estimar ambos componentes ortogonales de la maxima aceleracion horizontal del terreno, PGAh, y la vertical, PGAv, medidas en sitios en roca durante terremotos generados en la zona de subduccion de la Republica Mexicana. El trabajo discute el desarrollo, entrenamiento, y prueba de este modelo neuronal. El fenomeno de atenuacion fue caracterizado en terminos de la magnitud, la distancia epicentral y la profundidad focal. Aproximaciones neuronales fueron utilizadas en lugar de tecnicas de regresion tradicionales por su flexibilidad para tratar con incertidumbre y ruido en los datos. La NN sigue de cerca la respuesta medida exhibiendo capacidades predictivas mejores que las mostradas por muchas de las relaciones de atenuacion establecidas para la zona de

  14. Effects of slip-induced changes in ankle movement on muscle activity and ground reaction forces during running acceleration

    DEFF Research Database (Denmark)

    Ketabi, Shahin; Kersting, Uwe G.

    2013-01-01

    Ground contact in running is always linked to a minimum amount of slipping, e.g., during the early contact phase when horizontal forces are high compared to vertical forces. Studies have shown altered muscular activation when expecting slips [2-4]. It is not known what the mechanical effect of su...... of such slip episodes are on joint loading or performance. The aim of the present study was to examine the effect of changes in ankle movement on ankle joint loading, muscle activity, and ground reaction forces during linear acceleration....

  15. Hoof accelerations and ground reaction forces of Thoroughbred racehorses measured on dirt, synthetic, and turf track surfaces.

    Science.gov (United States)

    Setterbo, Jacob J; Garcia, Tanya C; Campbell, Ian P; Reese, Jennifer L; Morgan, Jessica M; Kim, Sun Y; Hubbard, Mont; Stover, Susan M

    2009-10-01

    To compare hoof acceleration and ground reaction force (GRF) data among dirt, synthetic, and turf surfaces in Thoroughbred racehorses. 3 healthy Thoroughbred racehorses. Forelimb hoof accelerations and GRFs were measured with an accelerometer and a dynamometric horseshoe during trot and canter on dirt, synthetic, and turf track surfaces at a racecourse. Maxima, minima, temporal components, and a measure of vibration were extracted from the data. Acceleration and GRF variables were compared statistically among surfaces. The synthetic surface often had the lowest peak accelerations, mean vibration, and peak GRFs. Peak acceleration during hoof landing was significantly smaller for the synthetic surface (mean + or - SE, 28.5g + or - 2.9g) than for the turf surface (42.9g + or - 3.8g). Hoof vibrations during hoof landing for the synthetic surface were dirt and turf surfaces. Peak GRF for the synthetic surface (11.5 + or - 0.4 N/kg) was 83% and 71% of those for the dirt (13.8 + or - 0.3 N/kg) and turf surfaces (16.1 + or - 0.7 N/kg), respectively. The relatively low hoof accelerations, vibrations, and peak GRFs associated with the synthetic surface evaluated in the present study indicated that synthetic surfaces have potential for injury reduction in Thoroughbred racehorses. However, because of the unique material properties and different nature of individual dirt, synthetic, and turf racetrack surfaces, extending the results of this study to encompass all track surfaces should be done with caution.

  16. Alterations to the orientation of the ground reaction force vector affect sprint acceleration performance in team sports athletes.

    Science.gov (United States)

    Bezodis, Neil E; North, Jamie S; Razavet, Jane L

    2017-09-01

    A more horizontally oriented ground reaction force vector is related to higher levels of sprint acceleration performance across a range of athletes. However, the effects of acute experimental alterations to the force vector orientation within athletes are unknown. Fifteen male team sports athletes completed maximal effort 10-m accelerations in three conditions following different verbal instructions intended to manipulate the force vector orientation. Ground reaction forces (GRFs) were collected from the step nearest 5-m and stance leg kinematics at touchdown were also analysed to understand specific kinematic features of touchdown technique which may influence the consequent force vector orientation. Magnitude-based inferences were used to compare findings between conditions. There was a likely more horizontally oriented ground reaction force vector and a likely lower peak vertical force in the control condition compared with the experimental conditions. 10-m sprint time was very likely quickest in the control condition which confirmed the importance of force vector orientation for acceleration performance on a within-athlete basis. The stance leg kinematics revealed that a more horizontally oriented force vector during stance was preceded at touchdown by a likely more dorsiflexed ankle, a likely more flexed knee, and a possibly or likely greater hip extension velocity.

  17. Seismic fragility formulations for segmented buried pipeline systems including the impact of differential ground subsidence

    Energy Technology Data Exchange (ETDEWEB)

    Pineda Porras, Omar Andrey [Los Alamos National Laboratory; Ordaz, Mario [UNAM, MEXICO CITY

    2009-01-01

    Though Differential Ground Subsidence (DGS) impacts the seismic response of segmented buried pipelines augmenting their vulnerability, fragility formulations to estimate repair rates under such condition are not available in the literature. Physical models to estimate pipeline seismic damage considering other cases of permanent ground subsidence (e.g. faulting, tectonic uplift, liquefaction, and landslides) have been extensively reported, not being the case of DGS. The refinement of the study of two important phenomena in Mexico City - the 1985 Michoacan earthquake scenario and the sinking of the city due to ground subsidence - has contributed to the analysis of the interrelation of pipeline damage, ground motion intensity, and DGS; from the analysis of the 48-inch pipeline network of the Mexico City's Water System, fragility formulations for segmented buried pipeline systems for two DGS levels are proposed. The novel parameter PGV{sup 2}/PGA, being PGV peak ground velocity and PGA peak ground acceleration, has been used as seismic parameter in these formulations, since it has shown better correlation to pipeline damage than PGV alone according to previous studies. By comparing the proposed fragilities, it is concluded that a change in the DGS level (from Low-Medium to High) could increase the pipeline repair rates (number of repairs per kilometer) by factors ranging from 1.3 to 2.0; being the higher the seismic intensity the lower the factor.

  18. Accelerators

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    The talk summarizes the principles of particle acceleration and addresses problems related to storage rings like LEP and LHC. Special emphasis will be given to orbit stability, long term stability of the particle motion, collective effects and synchrotron radiation.

  19. On the dependency of the decay of ground motion peak values with distance for small and large earthquakes

    Science.gov (United States)

    Dujardin, Alain; Courboulex, Françoise; Causse, Matthieu; Traversa, Paola; Monfret, Tony

    2013-04-01

    Ground motion decay with distance presents a clear magnitude dependence, PGA values of small events decreasing faster than those of larger events. This observation is now widely accepted and often taken into account in recent ground motion prediction equations (Anderson 2005, Akkar & Bommer 2010). The aim of this study is to investigate the origin of this dependence, which has not been clearly identified yet. Two main hypotheses are considered. On one hand the difference of ground motion decay is related to an attenuation effect, on the other hand the difference is related to an effect of extended fault (Anderson 2000). To study the role of attenuation, we realized synthetic tests using the stochastic simulation program SMSIM from Boore (2005). We build a set of simulations from several magnitudes and epicentral distances, and observe that the decay in PGA values is strongly dependent on the spectral shape of the Fourier spectra, which in turn strongly depends on the attenuation factor (Q(f) or kappa). We found that, for a point source approximation and an infinite value of Q (no attenuation) there is no difference between small and large events and that this difference increases when Q decreases. Theses results show that the influence of attenuation on spectral shape is different for earthquakes of different magnitude. In fact the influence of attenuation, which is more important at higher frequency, is larger for small earthquakes, whose Fourier acceleration spectrum has predominantly higher frequencies. We then study the effect of extended source using complete waveform simulations in a 1D model. We find that when the duration of the source time function increases, there is a larger probability to obtain large PGA values at equivalent distances. This effect could also play an important role in the PGA decay with magnitude and distance. Finally we compare these results with real datasets from the Japanese accelerometric network KIK-net.

  20. Fatty acid synthesis by spinach chloroplasts, 2. The path from PGA to fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Mitsuhiro; Nakamura, Yasunori [Tokyo Univ. (Japan). Coll. of General Education

    1975-02-01

    By incorporation of /sup 3/H/sub 2/O into the fatty acid chain in the presence of unlabelled precursor, we showed that fatty acids are synthesized from PGA, PEP and pyruvate by intact spinach chloroplasts in the light. /sup 13/C-tracer experiments confirmed that 1-C of pyruvate is decarboxylated and 2-C is incorporated into fatty acids by the chloroplasts. The patterns of fatty acids synthesized from PGA and pyruvate were the same as that from acetate. The highest rate of fatty acid synthesis was reached at the physiological concentration of PGA (3 mM) and pyruvate (1 mM). These results indicate the operation of the following path in the chloroplasts in light: PGA..-->..PEP..-->..pyruvate..-->..acetylCoA..-->..fatty acids. Since citrate and OAA were much less active and malate and glyoxylate were inert as precursors for fatty acid synthesis, PEP or pyruvate carboxylation, citrate lyase reaction and malate synthetase reaction are not involved in the formation of acetylCoA and fatty acids. Since pyruvate was much more effective as a substrate for fatty acid synthesis than lactate, acetaldehyde or acetate, direct decarboxylation path is considered to be the primary path from pyruvate to acetylCoA. The insignificant effect of chloroplast-washing on fatty acid synthesis from PGA and pyruvate indicates that the glycolytic path from PGA to pyruvate is associated with the chloroplasts. Since pyruvate was more effectively incorporated into fatty acids than acetylCoA, it is unlikely that pyruvate decarboxylation to acetylCoA is due to mitochondria contaminating the chloroplast preparation. On the basis of measurements of /sup 3/H/sub 2/O incorporation in the light and dark, the activity of fatty acid synthesis in spincah leaves appears to be shared by the activities in chloroplasts (87%) and other organelles (13%).

  1. Gait Phases Recognition from Accelerations and Ground Reaction Forces: Application of Neural Networks

    Directory of Open Access Journals (Sweden)

    S. Rafajlović

    2009-06-01

    Full Text Available The goal of this study was to test the applicability of accelerometer as the sensor for assessment of the walking. We present here the comparison of gait phases detected from the data recorded by force sensing resistors mounted in the shoe insoles, non-processed acceleration and processed acceleration perpendicular to the direction of the foot. The gait phases in all three cases were detected by means of a neural network. The output from the neural network was the gait phase, while the inputs were data from the sensors. The results show that the errors were in the ranges: 30 ms (2.7% – force sensors; 150 ms (13.6% – nonprocessed acceleration, and 120 ms (11% – processed acceleration data. This result suggests that it is possible to use the accelerometer as the gait phase detector, however, with the knowledge that the gait phases are time shifted for about 100 ms with respect the neural network predicted times.

  2. Chondrogenic differentiation of human articular chondrocytes differs in biodegradable PGA/PLA scaffolds

    DEFF Research Database (Denmark)

    Zwingmann, Joern; Mehlhorn, Alexander T; Südkamp, Norbert

    2007-01-01

    Cartilage tissue engineering is applied clinically to cover and regenerate articular cartilage defects. Two bioresorbable nonwoven scaffolds, polyglycolic acid (PGA) and poly(lactic-co-glycolic acid) (PLGA) (90/10 copolymer of L-lactide and glycolide), were seeded with human chondrocytes after in...

  3. Permafrost thawing in organic Arctic soils accelerated by ground heat production

    DEFF Research Database (Denmark)

    Hollesen, Jørgen; Matthiesen, Henning; Møller, Anders Bjørn

    2015-01-01

    Decomposition of organic carbon from thawing permafrost soils and the resulting release of carbon to the atmosphere are considered to represent a potentially critical global-scale feedback on climate change1, 2. The accompanying heat production from microbial metabolism of organic material has been...... recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon3, 4. This internal heat production is poorly understood, however, and the strength of this effect remains unclear3. Here, we have quantified the variability of heat production in contrasting...... organic permafrost soils across Greenland and tested the hypothesis that these soils produce enough heat to reach a tipping point after which internal heat production can accelerate the decomposition processes. Results show that the impact of climate changes on natural organic soils can be accelerated...

  4. Proteomic analysis of the signaling pathway mediated by the heterotrimeric Gα protein Pga1 of Penicillium chrysogenum.

    Science.gov (United States)

    Carrasco-Navarro, Ulises; Vera-Estrella, Rosario; Barkla, Bronwyn J; Zúñiga-León, Eduardo; Reyes-Vivas, Horacio; Fernández, Francisco J; Fierro, Francisco

    2016-10-06

    The heterotrimeric Gα protein Pga1-mediated signaling pathway regulates the entire developmental program in Penicillium chrysogenum, from spore germination to the formation of conidia. In addition it participates in the regulation of penicillin biosynthesis. We aimed to advance the understanding of this key signaling pathway using a proteomics approach, a powerful tool to identify effectors participating in signal transduction pathways. Penicillium chrysogenum mutants with different levels of activity of the Pga1-mediated signaling pathway were used to perform comparative proteomic analyses by 2D-DIGE and LC-MS/MS. Thirty proteins were identified which showed differences in abundance dependent on Pga1 activity level. By modifying the intracellular levels of cAMP we could establish cAMP-dependent and cAMP-independent pathways in Pga1-mediated signaling. Pga1 was shown to regulate abundance of enzymes in primary metabolic pathways involved in ATP, NADPH and cysteine biosynthesis, compounds that are needed for high levels of penicillin production. An in vivo phosphorylated protein containing a pleckstrin homology domain was identified; this protein is a candidate for signal transduction activity. Proteins with possible roles in purine metabolism, protein folding, stress response and morphogenesis were also identified whose abundance was regulated by Pga1 signaling. Thirty proteins whose abundance was regulated by the Pga1-mediated signaling pathway were identified. These proteins are involved in primary metabolism, stress response, development and signal transduction. A model describing the pathways through which Pga1 signaling regulates different cellular processes is proposed.

  5. Carboxamide Spleen Tyrosine Kinase (Syk) Inhibitors: Leveraging Ground State Interactions To Accelerate Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J. Michael; Altman, Michael D.; Cash, Brandon; Haidle, Andrew M.; Kubiak, Rachel L.; Maddess, Matthew L.; Yan, Youwei; Northrup, Alan B. (Merck)

    2016-12-08

    Optimization of a series of highly potent and kinome selective carbon-linked carboxamide spleen tyrosine kinase (Syk) inhibitors with favorable drug-like properties is described. A pervasive Ames liability in an analogous nitrogen-linked carboxamide series was obviated by replacement with a carbon-linked moiety. Initial efforts lacked on-target potency, likely due to strain induced between the hinge binding amide and solvent front heterocycle. Consideration of ground state and bound state energetics allowed rapid realization of improved solvent front substituents affording subnanomolar Syk potency and high kinome selectivity. These molecules were also devoid of mutagenicity risk as assessed via the Ames test using the TA97a Salmonella strain.

  6. Properties of starch-polyglutamic acid (PGA) graft copolymer prepared by microwave irradiation - Fourier transform infrared spectroscopy (FTIR) and rheology studies

    Science.gov (United States)

    The rheological properties of waxy starch-'-polygutamic acid (PGA) graft copolymers were investigated. Grafting was confirmed by FTIR spectroscopy. The starch-PGA copolymers absorbed water and formed gels, which exhibited concentration-dependent viscoelastic solid properties. Higher starch-PGA conce...

  7. Development of amphiphilic gamma-PGA-nanoparticle based tumor vaccine: potential of the nanoparticulate cytosolic protein delivery carrier.

    Science.gov (United States)

    Yoshikawa, Tomoaki; Okada, Naoki; Oda, Atsushi; Matsuo, Kazuhiko; Matsuo, Keisuke; Mukai, Yohei; Yoshioka, Yasuo; Akagi, Takami; Akashi, Mitsuru; Nakagawa, Shinsaku

    2008-02-08

    Nanoscopic therapeutic systems that incorporate biomacromolecules, such as protein and peptides, are emerging as the next generation of nanomedicine aimed at improving the therapeutic efficacy of biomacromolecular drugs. In this study, we report that poly(gamma-glutamic acid)-based nanoparticles (gamma-PGA NPs) are excellent protein delivery carriers for tumor vaccines that delivered antigenic proteins to antigen-presenting cells and elicited potent immune responses. Importantly, gamma-PGA NPs efficiently delivered entrapped antigenic proteins through cytosolic translocation from the endosomes, which is a key process of gamma-PGA NP-mediated anti-tumor immune responses. Our findings suggest that the gamma-PGA NP system is suitable for the intracellular delivery of protein-based drugs as well as tumor vaccines.

  8. In-vitro-Studie zum Einfluss von Fibrin in Knorpelkonstrukten auf der Basis von PGA-Vliesstoffen

    DEFF Research Database (Denmark)

    Schmal, H; Mehlhorn, A T; Kurze, C

    2008-01-01

    BACKGROUND: The matrix component in autologous chondrocyte implantation plays an important role. In this study the influence of an additional fibrin component in cartilage constructs based on polyglycolide polymers (PGA) was investigated. METHODS: Human chondrocytes of femoral heads were isolated....... CONCLUSION: Cartilage constructs based on carbohydrate matrices are suitable for matrix-associated chondrocyte implantation. The results of this study suggest a partially inhibitory effect of an additional fibrin component in PGA constructs for chondrogenic differentiation....

  9. The ShakeOut earthquake source and ground motion simulations

    Science.gov (United States)

    Graves, R.W.; Houston, Douglas B.; Hudnut, K.W.

    2011-01-01

    The ShakeOut Scenario is premised upon the detailed description of a hypothetical Mw 7.8 earthquake on the southern San Andreas Fault and the associated simulated ground motions. The main features of the scenario, such as its endpoints, magnitude, and gross slip distribution, were defined through expert opinion and incorporated information from many previous studies. Slip at smaller length scales, rupture speed, and rise time were constrained using empirical relationships and experience gained from previous strong-motion modeling. Using this rupture description and a 3-D model of the crust, broadband ground motions were computed over a large region of Southern California. The largest simulated peak ground acceleration (PGA) and peak ground velocity (PGV) generally range from 0.5 to 1.0 g and 100 to 250 cm/s, respectively, with the waveforms exhibiting strong directivity and basin effects. Use of a slip-predictable model results in a high static stress drop event and produces ground motions somewhat higher than median level predictions from NGA ground motion prediction equations (GMPEs).

  10. Non-woven PGA/PVA Fibrous Mesh as an Appropriate Scaffold for Chondrocyte Proliferation

    Czech Academy of Sciences Publication Activity Database

    Rampichová, Michala; Košťáková, E.; Filová, Eva; Prosecká, Eva; Plencner, Martin; Ocheretná, L.; Lytvynets, Andriy; Lukáš, D.; Amler, Evžen

    2010-01-01

    Roč. 59, č. 5 (2010), s. 773-781 ISSN 0862-8408 R&D Projects: GA AV ČR IAA500390702; GA ČR GAP304/10/1307 Grant - others:GA UK(CZ) 119209; EU(XE) BIOSCENT ID 214539; GA MŠk(CZ) 1M0510; GA ČR(CZ) GA202/09/1151; GA MŠk(CZ) 2B06130 Program:1M; GA; 2B Institutional research plan: CEZ:AV0Z50390703; CEZ:AV0Z50390512 Keywords : PGA * PVA * chondrocyte Subject RIV: BO - Biophysics Impact factor: 1.646, year: 2010

  11. Determination of radiochemical purity of 125I-TOC and 125I-F-PGA

    International Nuclear Information System (INIS)

    Yang Keya; Fan Wo; Zhang Youjiu; Xu Yujie; Zhu Ran; Hu Mingjiang

    2006-01-01

    To explore whether there is accordance among three determination methods of the radiochemical purity of [Tyr 3 ] octreotide (TOC) and folate-penicillin G amidase conjugate (F-PGA), which are both labeled with 125 I by Iodogen method, the RCP of the labelings are determined by high performance liquid chromatography (HPLC), paper chromatography and trichloroacetic acid (TCA) precipitation, in which four different concentrations of proteins are used to investigate the effect of them on the determination of RCP. It is shown that both HPLC and paper chromatography can separate the labelings from free iodine efficiently, though HPLC is the most precise and reliable method to determinate RCP of such labelings. In TCA precipitation, the RCP measured with 0.2%BSA is the lowest, but those with three other concentrations of the BSA are similar (P>0.05). When RCP 0.05), whereas higher than that with HPLC (P 10%, the RCP of 125 I-TOC obtained by TCA precipitation is a bit lower than those by two other methods (P 0.05), and there are no significant differences to determinate the RCP of 125 I-F-PGA (P>0.05). The three methods are correlated each other (r=0.0996-0.999, P<0.001). (authors)

  12. Ground failure in the 2001 Mw 8.4 southern Peru earthquake

    Science.gov (United States)

    Rondinel-Oviedo, Efrain Alejandro

    On June 23rd 2001 a moment magnitude (M W) 8.4, earthquake shook the southern portion of Peru. This rare large-magnitude event provided a unique opportunity to develop a suite of high quality case histories and also to test and calibrate existing geotechnical earthquake engineering analysis procedures and models against observations from the earthquake. The work presented in this thesis is focused on three topics pertaining to ground failure (i.e., the permanent deformation of the ground resulting from an earthquake) observed during the event: (1) surface ground damage in small basin geometries, (2) seismic compression, and (3) performance of a concrete faced rockfill dam (CFRD) dam. Surface ground strain damage patterns in small basin geometries has previously been typically studied at the large (i.e., geological) scale, but not at the scale of civil engineering infrastructure. During seismic events basin geometries containing soft material confined by stiffer material trap the seismic waves and generate surface waves that travel on the ground along the soft material. Numerical modeling shows that surface waves are generated at basin edges and travel on the ground creating higher duration, higher response (peak ground acceleration, PGA), higher energy (Arias Intensity) and higher angular distortion, especially in zones close to the edges. The impedance contrast between the stiff material and the soft material, and the dip angle play an important role in basin response. Seismic compression (i.e., the shaking induced densification of unsaturated soil) was observed in many highway embankments in the region of the earthquake. In many instances, this phenomenon was exasperated by soil-structure interaction with adjacent bridge or culvert structures. Numerical modeling conducted as part of this research showed (i) a significantly different response when the structure (culvert) is considered, (ii) impedance contrast plays a role in the system responses, and (iii) low

  13. Possible Mechanisms for Generation of Anomalously High PGA During the 2011 Tohoku Earthquake

    Science.gov (United States)

    Pavlenko, O. V.

    2017-08-01

    Mechanisms are suggested that could explain anomalously high PGAs (peak ground accelerations) exceeding 1 g recorded during the 2011 Tohoku earthquake ( M w = 9.0). In my previous research, I studied soil behavior during the Tohoku earthquake based on KiK-net vertical array records and revealed its `atypical' pattern: instead of being reduced in the near-source zones as usually observed during strong earthquakes, shear moduli in soil layers increased, indicating soil hardening, and reached their maxima at the moments of the highest intensity of strong motion, then reduced. We could explain this assuming that the soils experienced some additional compression. The observed changes in the shapes of acceleration time histories with distance from the source, such as a decrease of the duration and an increase of the intensity of strong motion, indicate phenomena similar to overlapping of seismic waves and a shock wave generation, which led to the compression of soils. The phenomena reach their maximum in the vicinity of stations FKSH10, TCGH16, and IBRH11, where the highest PGAs were recorded; at larger epicentral distances, PGAs sharply fall. Thus, the occurrence of anomalously high PGAs on the surface can result from the combination of the overlapping of seismic waves at the bottoms of soil layers and their increased amplification by the pre-compressed soils.

  14. Preliminary map of peak horizontal ground acceleration for the Hanshin-Awaji earthquake of January 17, 1995, Japan - Description of Mapped Data Sets

    Science.gov (United States)

    Borcherdt, R.D.; Mark, R.K.

    1995-01-01

    The Hanshin-Awaji earthquake (also known as the Hyogo-ken Nanbu and the Great Hanshin earthquake) provided an unprecedented set of measurements of strong ground shaking. The measurements constitute the most comprehensive set of strong- motion recordings yet obtained for sites underlain by soft soil deposits of Holocene age within a few kilometers of the crustal rupture zone. The recordings, obtained on or near many important structures, provide an important new empirical data set for evaluating input ground motion levels and site amplification factors for codes and site-specific design procedures world wide. This report describes the data used to prepare a preliminary map summarizing the strong motion data in relation to seismicity and underlying geology (Wentworth, Borcherdt, and Mark., 1995; Figure 1, hereafter referred to as Figure 1/I). The map shows station locations, peak acceleration values, and generalized acceleration contours superimposed on pertinent seismicity and the geologic map of Japan. The map (Figure 1/I) indicates a zone of high acceleration with ground motions throughout the zone greater than 400 gal and locally greater than 800 gal. This zone encompasses the area of most intense damage mapped as JMA intensity level 7, which extends through Kobe City. The zone of most intense damage is parallel, but displaced slightly from the surface projection of the crustal rupture zone implied by aftershock locations. The zone is underlain by soft-soil deposits of Holocene age.

  15. Understanding the magnitude dependence of PGA and PGV in NGA-West 2 data

    Science.gov (United States)

    Baltay, Annemarie S.; Hanks, Thomas C.

    2014-01-01

    The Next Generation Attenuation‐West 2 (NGA‐West 2) 2014 ground‐motion prediction equations (GMPEs) model ground motions as a function of magnitude and distance, using empirically derived coefficients (e.g., Bozorgniaet al., 2014); as such, these GMPEs do not clearly employ earthquake source parameters beyond moment magnitude (M) and focal mechanism. To better understand the magnitude‐dependent trends in the GMPEs, we build a comprehensive earthquake source‐based model to explain the magnitude dependence of peak ground acceleration and peak ground velocity in the NGA‐West 2 ground‐motion databases and GMPEs. Our model employs existing models (Hanks and McGuire, 1981; Boore, 1983, 1986; Anderson and Hough, 1984) that incorporate a point‐source Brune model, including a constant stress drop and the high‐frequency attenuation parameter κ0, random vibration theory, and a finite‐fault assumption at the large magnitudes to describe the data from magnitudes 3 to 8. We partition this range into four different magnitude regions, each of which has different functional dependences on M. Use of the four magnitude partitions separately allows greater understanding of what happens in any one subrange, as well as the limiting conditions between the subranges. This model provides a remarkably good fit to the NGA data for magnitudes from 3

  16. Near-Field Ground Motion Modal versus Wave Propagation Analysis

    Directory of Open Access Journals (Sweden)

    Artur Cichowicz

    2010-01-01

    Full Text Available The response spectrum generally provides a good estimate of the global displacement and acceleration demand of far-field ground motion on a structure. However, it does not provide accurate information on the local shape or internal deformation of the response of the structure. Near-field pulse-like ground motion will propagate through the structure as waves, causing large, localized deformation. Therefore, the response spectrum alone is not a sufficient representation of near-field ground motion features. Results show that the drift-response technique based on a continuous shear-beam model has to be employed here to estimate structure-demand parameters when structure is exposed to the pulse like ground motion. Conduced modeling shows limited applicability of the drift spectrum based on the SDOF approximation. The SDOF drift spectrum approximation can only be applied to structures with smaller natural periods than the dominant period of the ground motion. For periods larger than the dominant period of ground motion the SDOF drift spectra model significantly underestimates maximum deformation. Strong pulse-type motions are observed in the near-source region of large earthquakes; however, there is a lack of waveforms collected from small earthquakes at very close distances that were recorded underground in mines. The results presented in this paper are relevant for structures with a height of a few meters, placed in an underground excavation. The strong ground motion sensors recorded mine-induced earthquakes in a deep gold mine, South Africa. The strongest monitored horizontal ground motion was caused by an event of magnitude 2 at a distance of 90 m with PGA 123 m/s2, causing drifts of 0.25%–0.35%. The weak underground motion has spectral characteristics similar to the strong ground motion observed on the earth's surface; the drift spectrum has a maximum value less than 0.02%.

  17. Ebola Vaccination Using a DNA Vaccine Coated on PLGA-PLL/γPGA Nanoparticles Administered Using a Microneedle Patch.

    Science.gov (United States)

    Yang, Hung-Wei; Ye, Ling; Guo, Xin Dong; Yang, Chinglai; Compans, Richard W; Prausnitz, Mark R

    2017-01-01

    Ebola DNA vaccine is incorporated into PLGA-PLL/γPGA nanoparticles and administered to skin using a microneedle (MN) patch. The nanoparticle delivery system increases vaccine thermostability and immunogenicity compared to free vaccine. Vaccination by MN patch produces stronger immune responses than intramuscular administration. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Problems connected with the production of highly specific antisera against prostaglandin E2 (PGE2) and prostaglandin A2 (PGA2) for radioimmunoassay

    International Nuclear Information System (INIS)

    Kopp, H.G.; Vetter, W.; Siegenthaler, W.

    1978-01-01

    To obtain sensitive and specific antisera against PGE 2 and PGA 2 these substances were coupled to thyroglobulin (Tg). Coupling reactions were performed by using either a hydroxy-succinimide-ester as intermediate step leading to a complex carrying 170mol PGE 2 per mol Tg (''PGE 2 -OSU-Tg'') and 240mol PGA 2 per mol Tg (''PGA 2 -OSU-Tg''), or N, N'-carbonyl-diimidazole resulting in ''PGE 2 -CDI-Tg'' (400mol PGE 2 per mol Tg) and ''PGA 2 -CDI-Tg'' (600mol PGA 2 per mol Tg). Two tracer systems ( 3 H-prostaglandin and 125 I-histamine-prostaglandin) were used for analysis of antibody activity. The PGE 2 -CDI-Tg and PGA 2 -CDI-Tg complexes were both poor immunogens in rabbits. The PGE 2 -OSU-Tg and PGA 2 -OSU-Tg conjugates were injected in rabbits and in guinea-pigs. These two compounds resulted in very high antibody titres in both animal species. However, in guinea-pigs a markedly higher antibody sensitivity and antibody specificity were observed than in rabbits. Our results indicate that the guinea-pig may be the animal of choice for immunization against prostaglandins. Antibody specificity of guinea-pig antisera may be high enough to measure the concentration of PGE 2 and PGA 2 in the presence of other prostaglandins or prostaglandin metabolites. (author)

  19. Problems connected with the production of highly specific antisera against prostaglandin E2 (PGE2) and prostaglandin A2 (PGA2) for radioimmunoassay

    International Nuclear Information System (INIS)

    Kopp, H.G.; Vetter, W.; Siegenthaler, W.

    1977-01-01

    To obtain sensitive and specific antisera against PGE 2 and PGA 2 these substances were coupled to thyroglobulin (Tg). Coupling reactions were either performed by using a hydroxysuccinimideester as intermediate step leading to a complex carrying 170 mol PGE 2 per mol Tg ('PGE 2 -OSU-Tg') and 240 mol PGA 2 per mol Tg ('PGA 2 -OSU-Tg') or alternatively by using N,N'-carbonyl-diimidazole resulting in 'PGE 2 -CDI-Tg' (400 mol PGE 2 per mol Tg) and 'PGA 2 -CDI-Tg' (600 mol PGA 2 per mol Tg). Two tracer systems ( 3 H-prostaglandin, 125 I-histamine-prostaglandin) were used for analysis of antibody activity. Both PGE 2 - and PGA 2 -CDI-Tg complexes were poor immunogens in rabbits. The PGE 2 - and PGA 2 -OSU-Tg conjugates were injected both in rabbits and in guinea pigs. These two compounds resulted in very high antibody titers in both animal species. However, in guinea pigs markedly higher antibody sensitivity and antibody specificity were observed than in rabbits. Our results indicate that the guinea pig may be the animal of choice for immunization against prostaglandins. Antibody specificity of guinea pig antisera may be perhaps high enough to measure the concentration of PGE 2 and PGA 2 in the presence of other prostaglandins or prostaglandin metabolites. (orig.) [de

  20. SM-ROM-GL (Strong Motion Romania Ground Level Database

    Directory of Open Access Journals (Sweden)

    Ioan Sorin BORCIA

    2015-07-01

    Full Text Available The SM-ROM-GL database includes data obtained by the processing of records performed at ground level by the Romanian seismic networks, namely INCERC, NIEP, NCSRR and ISPH-GEOTEC, during recent seismic events with moment magnitude Mw ≥ 5 and epicenters located in Romania. All the available seismic records were re-processed using the same basic software and the same procedures and options (filtering and baseline correction, in order to obtain a consistent dataset. The database stores computed parameters of seismic motions, i.e. peak values: PGA, PGV, PGD, effective peak values: EPA, EPV, EPD, control periods, spectral values of absolute acceleration, relative velocity and relative displacement, as well as of instrumental intensity (as defined bz Sandi and Borcia in 2011. The fields in the database include: coding of seismic events, stations and records, a number of associated fields (seismic event source parameters, geographical coordinates of seismic stations, links to the corresponding ground motion records, charts of the response spectra of absolute acceleration, relative velocity, relative displacement and instrumental intensity, as well as some other representative parameters of seismic motions. The conception of the SM-ROM-GL database allows for an easy maintenance; such that elementary knowledge of Microsoft Access 2000 is sufficient for its operation.

  1. Completely non-destructive elemental analysis of bulky samples by PGA

    International Nuclear Information System (INIS)

    Oura, Y.; Nakahara, H.; Sueki, K.; Sato, W.; Tomizawa, T.

    1998-01-01

    A new non-destructive method is proposed for the elemental analysis of bulk samples. It is essentially a combination of PGA and NAA by a single neutron irradiation, and allows determinations of elemental contents of both major and minor constituents relative to that of some reference element. Major elements and some trace elements such as B, Sm, and Gd are mostly determined by the measurement of prompt gamma rays emitted when a bulky sample in its original form, namely, without any reduction of the sample size, is placed in the beam of neutrons guided from a nuclear reactor. Minor elements are then determined by the off-line measurements of gamma rays emitted from the radioactive nuclides produced within the sample by neutron capture reactions. As the radioactivity remaining in the sample becomes negligibly small after a few weeks cooling, the proposed method will be most usefully applied for the elemental analysis of bulky precious samples such as archaeological samples, and arts and crafts. In this presentation, applicability of the method will be demonstrated for porcelain and bronze samples. (author)

  2. Proteomic analysis of the signaling pathway mediated by the heterotrimeric G? protein Pga1 of Penicillium chrysogenum

    OpenAIRE

    Carrasco-Navarro, Ulises; Vera-Estrella, Rosario; Barkla, Bronwyn J.; Z??iga-Le?n, Eduardo; Reyes-Vivas, Horacio; Fern?ndez, Francisco J.; Fierro, Francisco

    2016-01-01

    Background The heterotrimeric G? protein Pga1-mediated signaling pathway regulates the entire developmental program in Penicillium chrysogenum, from spore germination to the formation of conidia. In addition it participates in the regulation of penicillin biosynthesis. We aimed to advance the understanding of this key signaling pathway using a proteomics approach, a powerful tool to identify effectors participating in signal transduction pathways. Results Penicillium chrysogenum mutants with ...

  3. Accelerated Time-Domain Modeling of Electromagnetic Pulse Excitation of Finite-Length Dissipative Conductors over a Ground Plane via Function Fitting and Recursive Convolution

    Energy Technology Data Exchange (ETDEWEB)

    Campione, Salvatore [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Warne, Larry K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sainath, Kamalesh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Basilio, Lorena I. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    In this report we overview the fundamental concepts for a pair of techniques which together greatly hasten computational predictions of electromagnetic pulse (EMP) excitation of finite-length dissipative conductors over a ground plane. In a time- domain, transmission line (TL) model implementation, predictions are computationally bottlenecked time-wise, either for late-time predictions (about 100ns-10000ns range) or predictions concerning EMP excitation of long TLs (order of kilometers or more ). This is because the method requires a temporal convolution to account for the losses in the ground. Addressing this to facilitate practical simulation of EMP excitation of TLs, we first apply a technique to extract an (approximate) complex exponential function basis-fit to the ground/Earth's impedance function, followed by incorporating this into a recursion-based convolution acceleration technique. Because the recursion-based method only requires the evaluation of the most recent voltage history data (versus the entire history in a "brute-force" convolution evaluation), we achieve necessary time speed- ups across a variety of TL/Earth geometry/material scenarios. Intentionally Left Blank

  4. Dry powder pulmonary delivery of cationic PGA-co-PDL nanoparticles with surface adsorbed model protein.

    Science.gov (United States)

    Kunda, Nitesh K; Alfagih, Iman M; Dennison, Sarah R; Somavarapu, Satyanarayana; Merchant, Zahra; Hutcheon, Gillian A; Saleem, Imran Y

    2015-08-15

    Pulmonary delivery of macromolecules has been the focus of attention as an alternate route of delivery with benefits such as; large surface area, thin alveolar epithelium, rapid absorption and extensive vasculature. In this study, a model protein, bovine serum albumin (BSA) was adsorbed onto cationic PGA-co-PDL polymeric nanoparticles (NPs) prepared by a single emulsion solvent evaporation method using a cationic surfactant didodecyldimethylammonium bromide (DMAB) at 2% w/w (particle size: 128.64±06.01 nm and zeta-potential: +42.32±02.70 mV). The optimum cationic NPs were then surface adsorbed with BSA, NP:BSA (100:4) ratio yielded 10.01±1.19 μg of BSA per mg of NPs. The BSA adsorbed NPs (5 mg/ml) were then spray-dried in an aqueous suspension of L-leucine (7.5 mg/ml, corresponding to a ratio of 1:1.5/NP:L-leu) using a Büchi-290 mini-spray dryer to produce nanocomposite microparticles (NCMPs) containing cationic NPs. The aerosol properties showed a fine particle fraction (FPF, dae<4.46 μm) of 70.67±4.07% and mass median aerodynamic diameter (MMAD) of 2.80±0.21 μm suggesting a deposition in the respiratory bronchiolar region of the lungs.The cell viability was 75.76±03.55% (A549 cell line) at 156.25 μg/ml concentration after 24 h exposure. SDS-PAGE and circular dichroism (CD) confirmed that the primary and secondary structure of the released BSA was maintained. Moreover, the released BSA showed 78.76±1.54% relative esterolytic activity compared to standard BSA. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Probabilistic low-rank factorization accelerates tensor network simulations of critical quantum many-body ground states

    Science.gov (United States)

    Kohn, Lucas; Tschirsich, Ferdinand; Keck, Maximilian; Plenio, Martin B.; Tamascelli, Dario; Montangero, Simone

    2018-01-01

    We provide evidence that randomized low-rank factorization is a powerful tool for the determination of the ground-state properties of low-dimensional lattice Hamiltonians through tensor network techniques. In particular, we show that randomized matrix factorization outperforms truncated singular value decomposition based on state-of-the-art deterministic routines in time-evolving block decimation (TEBD)- and density matrix renormalization group (DMRG)-style simulations, even when the system under study gets close to a phase transition: We report linear speedups in the bond or local dimension of up to 24 times in quasi-two-dimensional cylindrical systems.

  6. Complete nucleotide sequence of pGA45, a 140,698-bp incFIIY plasmid encoding blaIMI-3-mediated carbapenem resistance, from river sediment

    Directory of Open Access Journals (Sweden)

    Bingjun eDang

    2016-02-01

    Full Text Available Plasmid pGA45 was isolated from the sediment of Haihe River using E. coli CV601 (gfp-tagged as recipients and indigenous bacteria from sediment as donors. This plasmid confers reduced susceptibility to imipenem which belongs to carbapenem group. Plasmid pGA45 was fully sequenced on an Illumina HiSeq 2000 sequencing system. The complete sequence of plasmid pGA45 was 140,698 bp in length with an average G+C content of 52.03%. Sequence analysis shows that pGA45 belongs to incFIIY group and harbors a backbone region shares high homology and gene synteny to several other incF plasmids including pNDM1_EC14653, pYDC644, pNDM-Ec1GN574, pRJF866, pKOX_NDM1 and pP10164-NDM. In addition to the backbone region, plasmid pGA45 harbors two notable features including one blaIMI-3-containing region and one type VI secretion system region. The blaIMI-3-containing region is responsible for bacteria carbapenem resistance and the type VI secretion system region is probably involved in bacteria virulence, respectively. Plasmid pGA45 represents the first complete nucleotide sequence of the blaIMI-harboring plasmid from environment sample and the sequencing of this plasmid provided insight into the architecture used for the dissemination of blaIMI carbapenemase genes.

  7. A Bayesian and Physics-Based Ground Motion Parameters Map Generation System

    Science.gov (United States)

    Ramirez-Guzman, L.; Quiroz, A.; Sandoval, H.; Perez-Yanez, C.; Ruiz, A. L.; Delgado, R.; Macias, M. A.; Alcántara, L.

    2014-12-01

    We present the Ground Motion Parameters Map Generation (GMPMG) system developed by the Institute of Engineering at the National Autonomous University of Mexico (UNAM). The system delivers estimates of information associated with the social impact of earthquakes, engineering ground motion parameters (gmp), and macroseismic intensity maps. The gmp calculated are peak ground acceleration and velocity (pga and pgv) and response spectral acceleration (SA). The GMPMG relies on real-time data received from strong ground motion stations belonging to UNAM's networks throughout Mexico. Data are gathered via satellite and internet service providers, and managed with the data acquisition software Earthworm. The system is self-contained and can perform all calculations required for estimating gmp and intensity maps due to earthquakes, automatically or manually. An initial data processing, by baseline correcting and removing records containing glitches or low signal-to-noise ratio, is performed. The system then assigns a hypocentral location using first arrivals and a simplified 3D model, followed by a moment tensor inversion, which is performed using a pre-calculated Receiver Green's Tensors (RGT) database for a realistic 3D model of Mexico. A backup system to compute epicentral location and magnitude is in place. A Bayesian Kriging is employed to combine recorded values with grids of computed gmp. The latter are obtained by using appropriate ground motion prediction equations (for pgv, pga and SA with T=0.3, 0.5, 1 and 1.5 s ) and numerical simulations performed in real time, using the aforementioned RGT database (for SA with T=2, 2.5 and 3 s). Estimated intensity maps are then computed using SA(T=2S) to Modified Mercalli Intensity correlations derived for central Mexico. The maps are made available to the institutions in charge of the disaster prevention systems. In order to analyze the accuracy of the maps, we compare them against observations not considered in the

  8. Impact of ground motion characterization on conservatism and variability in seismic risk estimates

    International Nuclear Information System (INIS)

    Sewell, R.T.; Toro, G.R.; McGuire, R.K.

    1996-07-01

    This study evaluates the impact, on estimates of seismic risk and its uncertainty, of alternative methods in treatment and characterization of earthquake ground motions. The objective of this study is to delineate specific procedures and characterizations that may lead to less biased and more precise seismic risk results. This report focuses on sources of conservatism and variability in risk that may be introduced through the analytical processes and ground-motion descriptions which are commonly implemented at the interface of seismic hazard and fragility assessments. In particular, implication of the common practice of using a single, composite spectral shape to characterize motions of different magnitudes is investigated. Also, the impact of parameterization of ground motion on fragility and hazard assessments is shown. Examination of these results demonstrates the following. (1) There exists significant conservatism in the review spectra (usually, spectra characteristic of western U.S. earthquakes) that have been used in conducting past seismic risk assessments and seismic margin assessments for eastern U.S. nuclear power plants. (2) There is a strong dependence of seismic fragility on earthquake magnitude when PGA is used as the ground-motion characterization. When, however, magnitude-dependent spectra are anchored to a common measure of elastic spectral acceleration averaged over the appropriate frequency range, seismic fragility shows no important nor consistent dependence on either magnitude or strong-motion duration. Use of inelastic spectral acceleration (at the proper frequency) as the ground spectrum anchor demonstrates a very similar result. This study concludes that a single, composite-magnitude spectrum can generally be used to characterize ground motion for fragility assessment without introducing significant bias or uncertainty in seismic risk estimates

  9. Impact of ground motion characterization on conservatism and variability in seismic risk estimates

    Energy Technology Data Exchange (ETDEWEB)

    Sewell, R.T.; Toro, G.R.; McGuire, R.K.

    1996-07-01

    This study evaluates the impact, on estimates of seismic risk and its uncertainty, of alternative methods in treatment and characterization of earthquake ground motions. The objective of this study is to delineate specific procedures and characterizations that may lead to less biased and more precise seismic risk results. This report focuses on sources of conservatism and variability in risk that may be introduced through the analytical processes and ground-motion descriptions which are commonly implemented at the interface of seismic hazard and fragility assessments. In particular, implication of the common practice of using a single, composite spectral shape to characterize motions of different magnitudes is investigated. Also, the impact of parameterization of ground motion on fragility and hazard assessments is shown. Examination of these results demonstrates the following. (1) There exists significant conservatism in the review spectra (usually, spectra characteristic of western U.S. earthquakes) that have been used in conducting past seismic risk assessments and seismic margin assessments for eastern U.S. nuclear power plants. (2) There is a strong dependence of seismic fragility on earthquake magnitude when PGA is used as the ground-motion characterization. When, however, magnitude-dependent spectra are anchored to a common measure of elastic spectral acceleration averaged over the appropriate frequency range, seismic fragility shows no important nor consistent dependence on either magnitude or strong-motion duration. Use of inelastic spectral acceleration (at the proper frequency) as the ground spectrum anchor demonstrates a very similar result. This study concludes that a single, composite-magnitude spectrum can generally be used to characterize ground motion for fragility assessment without introducing significant bias or uncertainty in seismic risk estimates.

  10. Ground motion models used in the 2014 U.S. National Seismic Hazard Maps

    Science.gov (United States)

    Rezaeian, Sanaz; Petersen, Mark D.; Moschetti, Morgan P.

    2015-01-01

    The National Seismic Hazard Maps (NSHMs) are an important component of seismic design regulations in the United States. This paper compares hazard using the new suite of ground motion models (GMMs) relative to hazard using the suite of GMMs applied in the previous version of the maps. The new source characterization models are used for both cases. A previous paper (Rezaeian et al. 2014) discussed the five NGA-West2 GMMs used for shallow crustal earthquakes in the Western United States (WUS), which are also summarized here. Our focus in this paper is on GMMs for earthquakes in stable continental regions in the Central and Eastern United States (CEUS), as well as subduction interface and deep intraslab earthquakes. We consider building code hazard levels for peak ground acceleration (PGA), 0.2-s, and 1.0-s spectral accelerations (SAs) on uniform firm-rock site conditions. The GMM modifications in the updated version of the maps created changes in hazard within 5% to 20% in WUS; decreases within 5% to 20% in CEUS; changes within 5% to 15% for subduction interface earthquakes; and changes involving decreases of up to 50% and increases of up to 30% for deep intraslab earthquakes for most U.S. sites. These modifications were combined with changes resulting from modifications in the source characterization models to obtain the new hazard maps.

  11. Constraining ground motion parameters and determining the historic earthquake that damaged the vaults underneath the Old City of Jerusalem

    Science.gov (United States)

    Yagoda-Biran, G.; Hatzor, Y. H.

    2013-12-01

    Evidence for seismically induced damage are preserved in historic masonry structures below the Old City of Jerusalem at a site known locally as the 'Western Wall Tunnels' complex, possibly one of the most important tourist attractions in the world. In the tunnels, structures dated to 500 BC and up until modern times have been uncovered by recent archeological excavation. One of the interesting findings is a 100 m long bridge, composed of two rows of barrel vaults, believed to have been constructed during the 3rd century AD to allow easy access to the Temple Mount. In one of the vaults a single masonry block is displaced 7 cm downward with respect to its neighbors (see figure below). Since the damage seems seismically driven, back analysis of the damage with the numerical Discontinuous Deformation Analysis (DDA) method was performed, in order to constrain the peak ground acceleration (PGA) that had caused the damage. First the numerical method used for back analysis was verified with an analytical solution for the case of a rocking monolithic column, then validated with experimental results for site response analysis. The verification and validation prove the DDA is capable of handling dynamic and wave propagation problems. Next, the back analysis was performed. Results of the dynamic numerical simulations suggest that the damage observed at the vault was induced by seismic vibrations that must have taken place before the bridge was buried underground, namely when it was still in service. We find that the PGA required for causing the observed damage was high - between 1.5 and 2 g. The PGA calculated for Jerusalem on the basis of established attenuation relationships for historic earthquakes that struck the region during the relevant time period is about one order of magnitude lower: 0.14 and 0.48 g, for the events that took place at 362 and 746 AD, respectively. This discrepancy is explained by local site effects that must have amplified bedrock ground motions by a

  12. Bacterial-Derived Polymer Poly-γ-Glutamic Acid (γ-PGA)-Based Micro/Nanoparticles as a Delivery System for Antimicrobials and Other Biomedical Applications

    Science.gov (United States)

    Khalil, Ibrahim R.; Burns, Alan T. H.; Radecka, Iza; Kowalczuk, Marek; Khalaf, Tamara; Adamus, Grazyna; Johnston, Brian; Khechara, Martin P.

    2017-01-01

    In the past decade, poly-γ-glutamic acid (γ-PGA)-based micro/nanoparticles have garnered remarkable attention as antimicrobial agents and for drug delivery, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. γ-PGA is a naturally occurring biopolymer produced by several gram-positive bacteria that, due to its biodegradable, non-toxic and non-immunogenic properties, has been used successfully in the medical, food and wastewater industries. Moreover, its carboxylic group on the side chains can offer an attachment point to conjugate antimicrobial and various therapeutic agents, or to chemically modify the solubility of the biopolymer. The unique characteristics of γ-PGA have a promising future for medical and pharmaceutical applications. In the present review, the structure, properties and micro/nanoparticle preparation methods of γ-PGA and its derivatives are covered. Also, we have highlighted the impact of micro/nanoencapsulation or immobilisation of antimicrobial agents and various disease-related drugs on biodegradable γ-PGA micro/nanoparticles. PMID:28157175

  13. PROBABILISTIC SEISMIC ASSESSMENT OF BASE-ISOLATED NPPS SUBJECTED TO STRONG GROUND MOTIONS OF TOHOKU EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    AHMER ALI

    2014-10-01

    Full Text Available The probabilistic seismic performance of a standard Korean nuclear power plant (NPP with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

  14. Fault Structural Control on Earthquake Strong Ground Motions: The 2008 Wenchuan Earthquake as an Example

    Science.gov (United States)

    Zhang, Yan; Zhang, Dongli; Li, Xiaojun; Huang, Bei; Zheng, Wenjun; Wang, Yuejun

    2018-02-01

    Continental thrust faulting earthquakes pose severe threats to megacities across the world. Recent events show the possible control of fault structures on strong ground motions. The seismogenic structure of the 2008 Wenchuan earthquake is associated with high-angle listric reverse fault zones. Its peak ground accelerations (PGAs) show a prominent feature of fault zone amplification: the values within the 30- to 40-km-wide fault zone block are significantly larger than those on both the hanging wall and the footwall. The PGA values attenuate asymmetrically: they decay much more rapidly in the footwall than in the hanging wall. The hanging wall effects can be seen on both the vertical and horizontal components of the PGAs, with the former significantly more prominent than the latter. All these characteristics can be adequately interpreted by upward extrusion of the high-angle listric reverse fault zone block. Through comparison with a low-angle planar thrust fault associated with the 1999 Chi-Chi earthquake, we conclude that different fault structures might have controlled different patterns of strong ground motion, which should be taken into account in seismic design and construction.

  15. Probabilistic seismic assessment of base-isolated NPPs subjected to strong ground motions of Tohoku earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmer; Hayah, Nadin Abu; Kim, Doo Kie [Dept. of Civil and Environmental Engineering, Kunsan National University, Kunsan (Korea, Republic of); Cho, Sung Gook [R and D Center, JACE KOREA Company, Gyeonggido (Korea, Republic of)

    2014-10-15

    The probabilistic seismic performance of a standard Korean nuclear power plant (NPP) with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA) of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA) as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

  16. NGA-West2 equations for predicting vertical-component PGA, PGV, and 5%-damped PSA from shallow crustal earthquakes

    Science.gov (United States)

    Stewart, Jonathan P.; Boore, David M.; Seyhan, Emel; Atkinson, Gail M.

    2016-01-01

    We present ground motion prediction equations (GMPEs) for computing natural log means and standard deviations of vertical-component intensity measures (IMs) for shallow crustal earthquakes in active tectonic regions. The equations were derived from a global database with M 3.0–7.9 events. The functions are similar to those for our horizontal GMPEs. We derive equations for the primary M- and distance-dependence of peak acceleration, peak velocity, and 5%-damped pseudo-spectral accelerations at oscillator periods between 0.01–10 s. We observe pronounced M-dependent geometric spreading and region-dependent anelastic attenuation for high-frequency IMs. We do not observe significant region-dependence in site amplification. Aleatory uncertainty is found to decrease with increasing magnitude; within-event variability is independent of distance. Compared to our horizontal-component GMPEs, attenuation rates are broadly comparable (somewhat slower geometric spreading, faster apparent anelastic attenuation), VS30-scaling is reduced, nonlinear site response is much weaker, within-event variability is comparable, and between-event variability is greater.

  17. Comparison of Ground Motion Prediction Equations (GMPE) for Chile and Canada With Recent Chilean Megathust Earthquakes

    Science.gov (United States)

    Herrera, C.; Cassidy, J. F.; Dosso, S. E.

    2017-12-01

    The ground shaking assessment allows quantifying the hazards associated with the occurrence of earthquakes. Chile and western Canada are two areas that have experienced, and are susceptible to imminent large crustal, in-slab and megathrust earthquakes that can affect the population significantly. In this context, we compare the current GMPEs used in the 2015 National Building Code of Canada and the most recent GMPEs calculated for Chile, with observed accelerations generated by four recent Chilean megathrust earthquakes (MW ≥ 7.7) that have occurred during the past decade, which is essential to quantify how well current models predict observations of major events.We collected the 3-component waveform data of more than 90 stations from the Centro Sismologico Nacional and the Universidad de Chile, and processed them by removing the trend and applying a band-pass filter. Then, for each station, we obtained the Peak Ground Acceleration (PGA), and by using a damped response spectra, we calculated the Pseudo Spectral Acceleration (PSA). Finally, we compared those observations with the most recent Chilean and Canadian GMPEs. Given the lack of geotechnical information for most of the Chilean stations, we also used a new method to obtain the VS30 by inverting the H/V ratios using a trans-dimensional Bayesian inversion, which allows us to improve the correction of observations according to soil conditions.As expected, our results show a good fit between observations and the Chilean GMPEs, but we observe that although the shape of the Canadian GMPEs is coherent with the distribution of observations, in general they under predict the observations for PGA and PSA at shorter periods for most of the considered earthquakes. An example of this can be seen in the attached figure for the case of the 2014 Iquique earthquake.These results present important implications related to the hazards associated to large earthquakes, especially for western Canada, where the probability of a

  18. Preparation of biodegradable PLA/PLGA membranes with PGA mesh and their application for periodontal guided tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Jin; Kang, Inn-Kyu [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Yoon, Suk Joon [Department of Biology, Sookmyung Women' s University, Hyochangwongil 52, Yongsan-gu, Seoul 140-742 (Korea, Republic of); Yeo, Guw-Dong; Pai, Chaul-Min, E-mail: ikkang@knu.ac.k [Samyang Central R and D Center, 63-2 Hwaam-dong, Yusung-gu, Daejeon 305-717 (Korea, Republic of)

    2009-10-15

    A biodegradable polylactic acid (PLA)/poly(glycolide-co-lactide) copolymer (PLGA) membrane with polyglycolic acid (PGA) mesh was prepared to aid the effective regeneration of defective periodontal tissues. The microporous membrane used in this study consists of biodegradable polymers, and seems to have a structure to provide appropriate properties for periodontal tissue regeneration. Based on the albumin permeation test, it is known that the biodegradable membrane exhibits the suitable permeability of nutrients. The membrane maintained its physical integrity for 6-8 weeks, which could be sufficient to retain space in the periodontal pocket. Cell attachment and cytotoxicity tests were performed with respect to the evaluation of biocompatibility of the membrane. As a result, the membrane did not show any cytotoxicity. The safety and therapeutic efficacies of the biodegradable membranes were confirmed in animal tests.

  19. Production of Medium Chain Length Polyhydroxyalkanoates From Oleic Acid Using Pseudomonas putida PGA1 by Fed Batch Culture

    Directory of Open Access Journals (Sweden)

    Sidik Marsudi

    2010-10-01

    Full Text Available Bacterial polyhydroxyalkanoates (PHAs are a class of p0lymers currently receiving much attention because of their potential as renewable and biodegradable plastics. A wide variety of bacteria has been reported to produce PHAs including Pseudomonas strains. These strains are known as versatile medium chain length PHAs (PHAs-mcl producers using fatty acids as carbon source. Oleic acid was used to produce PHAs-mcl using Pseudomonas putida PGA 1 by continuous feeding of both nitrogen and carbon source, in a fed batch culture. During cell growth, PHAs also accumulated, indicating that PHA production in this organism is growth associated. Residual cell increased until the nitrogen source was depleted. At the end of fermentation, final cell concentration, PHA content, and roductivity were 30.2 g/L, 44.8 % of cell dry weight, and 0.188 g/l/h, respectively.

  20. Interaction between stope support and ground motion in the hangingwall and footwall Project.

    CSIR Research Space (South Africa)

    Cichowicz, A

    2002-07-01

    Full Text Available and limitations were verified by detailed testing with the strong ground motion data. The support response may be simulated using SDOF model when PGA is in the range 18 - 100 m/s2 ; for this data model shows that the maximal value of the stiffness is 120,000 k...

  1. A Study of the Oxidation Behaviour of Pile Grade A (PGA) Nuclear Graphite Using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Tomography (XRT).

    Science.gov (United States)

    Payne, Liam; Heard, Peter J; Scott, Thomas B

    2015-01-01

    Pile grade A (PGA) graphite was used as a material for moderating and reflecting neutrons in the UK's first generation Magnox nuclear power reactors. As all but one of these reactors are now shut down there is a need to understand the residual state of the material prior to decommissioning of the cores, in particular the location and concentration of key radio-contaminants such as 14C. The oxidation behaviour of unirradiated PGA graphite was studied, in the temperature range 600-1050°C, in air and nitrogen using thermogravimetric analysis, scanning electron microscopy and X-ray tomography to investigate the possibility of using thermal degradation techniques to examine 14C distribution within irradiated material. The thermal decomposition of PGA graphite was observed to follow the three oxidation regimes historically identified by previous workers with limited, uniform oxidation at temperatures below 600°C and substantial, external oxidation at higher temperatures. This work demonstrates that the different oxidation regimes of PGA graphite could be developed into a methodology to characterise the distribution and concentration of 14C in irradiated graphite by thermal treatment.

  2. Increasing the bioflocculant production and identifying the effect of overexpressing epsB on the synthesis of polysaccharide and γ-PGA in Bacillus licheniformis.

    Science.gov (United States)

    Liu, Peize; Chen, Zhen; Yang, Lijie; Li, Qingbiao; He, Ning

    2017-09-26

    Polysaccharides and poly-γ-glutamic acid (γ-PGA) are biomacromolecules that have been reported as bioflocculants, and they exhibit high flocculating activity in many industrial applications. Bacillus licheniformis CGMCC 2876 can produce polysaccharide and γ-PGA bioflocculants under different culture conditions. Several key genes are involved in the metabolic pathway of polysaccharides in B. licheniformis, but the impacts of the regulation of these genes on the production of polysaccharide bioflocculants have not been illustrated completely. To increase the bioflocculant production and identify the correlation between the synthesis of polysaccharides and γ-PGA in B. licheniformis, a few key genes were investigated to explore their influence on the synthesis of the bioflocculants. Overexpressing epsB from the eps gene cluster not only improved the bioflocculant crude yield by 13.98% but also enhanced the flocculating activity by 117.92%. The composition of the bioflocculant from the epsB recombinant strain was 28.95% total sugar, 3.464% protein and 44.03% γ-PGA, while in the original strain, these components represented 53.67%, 3.246% and 34.13%, respectively. In combination with an analysis of the transcriptional levels of several key genes involved in γ-PGA synthesis in B. licheniformis, we inferred that epsB played a key role in the synthesis of both polysaccharide and γ-PGA. The bioflocculant production of the epsB recombinant strain was further evaluated during batch fermentation in a 2 L fermenter; the flocculating activity reached 9612.75 U/mL, and the bioflocculant yield reached 10.26 g/L after 72 h, representing increases of 224% and 36.62%, respectively, compared with the original strain. Moreover, we found that the tandem expression of phosphoglucomutase (pgcA) and UTP-glucose-1-phosphate uridylyltransferase (gtaB1) could enhance the crude yield of the bioflocculant by 20.77% and that the overexpression of epsA could enhance the bioflocculant

  3. Prediction of modified Mercalli intensity from PGA, PGV, moment magnitude, and epicentral distance using several nonlinear statistical algorithms

    Science.gov (United States)

    Alvarez, Diego A.; Hurtado, Jorge E.; Bedoya-Ruíz, Daniel Alveiro

    2012-07-01

    Despite technological advances in seismic instrumentation, the assessment of the intensity of an earthquake using an observational scale as given, for example, by the modified Mercalli intensity scale is highly useful for practical purposes. In order to link the qualitative numbers extracted from the acceleration record of an earthquake and other instrumental data such as peak ground velocity, epicentral distance, and moment magnitude on the one hand and the modified Mercalli intensity scale on the other, simple statistical regression has been generally employed. In this paper, we will employ three methods of nonlinear regression, namely support vector regression, multilayer perceptrons, and genetic programming in order to find a functional dependence between the instrumental records and the modified Mercalli intensity scale. The proposed methods predict the intensity of an earthquake while dealing with nonlinearity and the noise inherent to the data. The nonlinear regressions with good estimation results have been performed using the "Did You Feel It?" database of the US Geological Survey and the database of the Center for Engineering Strong Motion Data for the California region.

  4. Evaluation of site effects on ground motions based on equivalent linear site response analysis and liquefaction potential in Chennai, south India

    Science.gov (United States)

    Nampally, Subhadra; Padhy, Simanchal; Trupti, S.; Prabhakar Prasad, P.; Seshunarayana, T.

    2018-05-01

    We study local site effects with detailed geotechnical and geophysical site characterization to evaluate the site-specific seismic hazard for the seismic microzonation of the Chennai city in South India. A Maximum Credible Earthquake (MCE) of magnitude 6.0 is considered based on the available seismotectonic and geological information of the study area. We synthesized strong ground motion records for this target event using stochastic finite-fault technique, based on a dynamic corner frequency approach, at different sites in the city, with the model parameters for the source, site, and path (attenuation) most appropriately selected for this region. We tested the influence of several model parameters on the characteristics of ground motion through simulations and found that stress drop largely influences both the amplitude and frequency of ground motion. To minimize its influence, we estimated stress drop after finite bandwidth correction, as expected from an M6 earthquake in Indian peninsula shield for accurately predicting the level of ground motion. Estimates of shear wave velocity averaged over the top 30 m of soil (V S30) are obtained from multichannel analysis of surface wave (MASW) at 210 sites at depths of 30 to 60 m below the ground surface. Using these V S30 values, along with the available geotechnical information and synthetic ground motion database obtained, equivalent linear one-dimensional site response analysis that approximates the nonlinear soil behavior within the linear analysis framework was performed using the computer program SHAKE2000. Fundamental natural frequency, Peak Ground Acceleration (PGA) at surface and rock levels, response spectrum at surface level for different damping coefficients, and amplification factors are presented at different sites of the city. Liquefaction study was done based on the V S30 and PGA values obtained. The major findings suggest show that the northeast part of the city is characterized by (i) low V S30 values

  5. Synthesis and Structural Characterization of Bioactive PHA and γ-PGA Oligomers for Potential Applications as a Delivery System

    Directory of Open Access Journals (Sweden)

    Iwona Kwiecień

    2016-04-01

    Full Text Available The (transesterification reaction of bacterial biopolymers with a selected bioactive compound with a hydroxyl group was applied as a convenient method for obtaining conjugates of such compound. Tyrosol, a naturally occurring phenolic compound, was selected as a model of a bioactive compound with a hydroxyl group. Selected biodegradable polyester and polyamide, poly(3-hydroxybutyrate-co-4-hydroxybutyrate (P(3HB-co-4HB and poly-γ-glutamic acid (γ-PGA, respectively, were used. The (transesterification reactions were carried out in melt mediated by 4-toluenesulfonic acid monohydrate. The structures of (transesterification products were established at the molecular level with the aid of ESI-MS2 (electrospray ionization tandem mass spectrometry and/or 1H NMR (nuclear magnetic resonance techniques. Performed analyses confirmed that the developed method leads to the formation of conjugates in which bioactive compounds are covalently bonded to biopolymer chains. The amount of covalently bonded bioactive compounds in the resulting conjugates depends on the type of biopolymers applied in synthesis.

  6. On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs)

    Science.gov (United States)

    Bora, Sanjay; Scherbaum, Frank; Kuehn, Nicolas; Stafford, Peter

    2016-04-01

    oscillator-frequency response spectral ordinates are controlled by a rather wide-band of Fourier spectral ordinates. In fact, the peak ground acceleration (PGA), counter to the popular perception that it is a reflection of the high-frequency characteristics of ground motion, is controlled by the entire Fourier spectrum of ground-motion. Finally, it is demonstrated, how an adjustment made in Fourier spectral amplitudes is different or similar to the same adjustment made in the response spectral amplitudes. For this purpose, two cases: adjustments to the stress parameter (Δσ) (source term) and to attributes reflecting site response (V s-κ0) are considered.

  7. Estimating the upper limit of prehistoric peak ground acceleration using an in situ, intact and vulnerable stalagmite from Plavecká priepast cave (Detrekői-zsomboly), Little Carpathians, Slovakia - first results\

    Czech Academy of Sciences Publication Activity Database

    Gribovszki, K.; Kovács, K.; Mónus, P.; Bokelmann, G.; Konečný, P.; Lednická, Markéta; Moseley, G.; Spötl, C.; Edwards, R. L.; Bednárik, M.; Brimich, L.; Tóth, L.

    2017-01-01

    Roč. 21, č. 5 (2017), s. 1111-1130 ISSN 1383-4649 R&D Projects: GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : speleology * cantilever beam * natural frequency * peak ground acceleration * speleoseismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Environmental and geological engineering, geotechnics Impact factor: 1.089, year: 2016 https://link.springer.com/content/pdf/10.1007%2Fs10950-017-9655-3.pdf

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

    Science.gov (United States)

    Reddell, Brandon

    2015-01-01

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

  9. Source and ground-motion parameters of the 2011 Lorca earthquake; Parametros de la fuente y del movimiento del suelo del terremoto de Lorca de 2011

    Energy Technology Data Exchange (ETDEWEB)

    Alguacil de la Blanca, G.; Vidal Sanchez, F.; Stich, D.; Mancilla Perez, F. L.; Lopez Comino, J. A.; Morales Soto, J.; Navarro Bernal, M.

    2012-07-01

    113 events of the Lorca seismic series has been relocated by using Double difference algorithm and data from both temporary and permanent seismic networks. Relocations yield shallow hypo central distribution of aftershocks with a {approx}5 km long, NE-SW trending, placed SW of the mainshock, suggesting a SW propagating rupture along the Alhama de Murcia fault. Similar oblique reverse faulting mechanism has been obtained for three largest events. Source parameters of these three earthquakes have been estimated. Horizontal ground motion was estimated at 11 city points whose local structure was known by SPAC experiments. A set of ground motion parameters (PGA, PGV, AI, CAV, SI, SA and SV) here calculated, have higher values at these points respect to the ones at LOR station. All parameter values are also above the expected values for Euro -Mediterranean earthquakes with local intensity VIII (EMS). Nevertheless, SD values are unusually short and less than the reference ones. Higher values of the response spectra of acceleration and velocity are given for periods of less than 0.7 s, with maximum spectral acceleration at 0.15 s and velocity at 0.5 s. The elastic input energy spectrum is well connected to the shake destructiveness in each place. Equivalent velocity > 60 cm/s is found in almost all sites and > 100 cm/s (for periods 0.3 to 0.6 s) in someone. Factors such as proximity, and focal mechanism and ground response characteristics explain the high ground motion parameter values obtained in Lorca sites and show the great influence of the source and site conditions on the characteristics of strong ground motion in the vicinity of the rupture. (Author) 68 refs.

  10. Seismic hazard in Hawaii: High rate of large earthquakes and probabilistics ground-motion maps

    Science.gov (United States)

    Klein, F.W.; Frankel, A.D.; Mueller, C.S.; Wesson, R.L.; Okubo, P.G.

    2001-01-01

    The seismic hazard and earthquake occurrence rates in Hawaii are locally as high as that near the most hazardous faults elsewhere in the United States. We have generated maps of peak ground acceleration (PGA) and spectral acceleration (SA) (at 0.2, 0.3 and 1.0 sec, 5% critical damping) at 2% and 10% exceedance probabilities in 50 years. The highest hazard is on the south side of Hawaii Island, as indicated by the MI 7.0, MS 7.2, and MI 7.9 earthquakes, which occurred there since 1868. Probabilistic values of horizontal PGA (2% in 50 years) on Hawaii's south coast exceed 1.75g. Because some large earthquake aftershock zones and the geometry of flank blocks slipping on subhorizontal decollement faults are known, we use a combination of spatially uniform sources in active flank blocks and smoothed seismicity in other areas to model seismicity. Rates of earthquakes are derived from magnitude distributions of the modem (1959-1997) catalog of the Hawaiian Volcano Observatory's seismic network supplemented by the historic (1868-1959) catalog. Modern magnitudes are ML measured on a Wood-Anderson seismograph or MS. Historic magnitudes may add ML measured on a Milne-Shaw or Bosch-Omori seismograph or MI derived from calibrated areas of MM intensities. Active flank areas, which by far account for the highest hazard, are characterized by distributions with b slopes of about 1.0 below M 5.0 and about 0.6 above M 5.0. The kinked distribution means that large earthquake rates would be grossly under-estimated by extrapolating small earthquake rates, and that longer catalogs are essential for estimating or verifying the rates of large earthquakes. Flank earthquakes thus follow a semicharacteristic model, which is a combination of background seismicity and an excess number of large earthquakes. Flank earthquakes are geometrically confined to rupture zones on the volcano flanks by barriers such as rift zones and the seaward edge of the volcano, which may be expressed by a magnitude

  11. Influence of surface-normal ground acceleration on the initiation of the Jih-Feng-Erh-Shan landslide during the 1999 Chi-Chi, Taiwan, earthquake

    Science.gov (United States)

    Huang, C.-C.; Lee, Y.-H.; Liu, Huaibao P.; Keefer, D.K.; Jibson, R.W.

    2001-01-01

    The 1999 Chi-Chi, Taiwan, earthquake triggered numerous landslides throughout a large area in the Central Range, to the east, southeast, and south of the fault rupture. Among them are two large rock avalanches, at Tsaoling and at Jih-Feng-Erh-Shan. At Jih-Feng-Erh-Shan, the entire thickness (30-50 m) of the Miocene Changhukeng Shale over an area of 1 km2 slid down its bedding plane for a distance of about 1 km. Initial movement of the landslide was nearly purely translational. We investigate the effect of surface-normal acceleration on the initiation of the Jih-Feng-Erh-Shan landslide using a block slide model. We show that this acceleration, currently not considered by dynamic slope-stability analysis methods, significantly influences the initiation of the landslide.

  12. Ground Motion Prediction Equations for Western Saudi Arabia from a Reference Model

    Science.gov (United States)

    Kiuchi, R.; Mooney, W. D.; Mori, J. J.; Zahran, H. M.; Al-Raddadi, W.; Youssef, S.

    2017-12-01

    Western Saudi Arabia is surrounded by several active seismic zones such as the Red Sea and the Gulf of Aqaba where a destructive magnitude 7.3 event occurred in 1995. Over the last decade, the Saudi Geological Survey (SGS) has deployed a dense seismic network that has made it possible to monitor seismic activity more accurately. For example, the network has detected multiple seismic swarms beneath the volcanic fields in western Saudi Arabia. The most recent damaging event was a M5.7 earthquake that occurred in 2009 at Harrat Lunayyir. In terms of seismic hazard assessment, Zahran et al. (2015; 2016) presented a Probabilistic Seismic Hazard Assessment (PSHA) for western Saudi Arabia that was developed using published Ground Motion Prediction Equations (GMPEs) from areas outside of Saudi Arabia. In this study, we consider 41 earthquakes of M 3.0 - 5.4, recorded on 124 stations of the SGS network, to create a set of 442 peak ground acceleration (PGA) and peak ground velocity (PGV) records with a range of epicentral distances from 3 km to 400 km. We use the GMPE model BSSA14 (Boore et al., 2014) as a reference model to estimate our own best-fitting coefficients from a regression analysis using the events occurred in western Saudi Arabia. For epicentral distances less than 100 km, our best fitting model has different source scaling in comparison with the GMPE of BSSA14 adjusted for the California region. In addition, our model indicates that the peak amplitudes have less attenuation in western Saudi Arabia than in California.

  13. Ground Motion Prediction Model Using Adaptive Neuro-Fuzzy Inference Systems: An Example Based on the NGA-West 2 Data

    Science.gov (United States)

    Ameur, Mourad; Derras, Boumédiène; Zendagui, Djawed

    2018-03-01

    Adaptive neuro-fuzzy inference systems (ANFIS) are used here to obtain the robust ground motion prediction model (GMPM). Avoiding a priori functional form, ANFIS provides fully data-driven predictive models. A large subset of the NGA-West2 database is used, including 2335 records from 580 sites and 137 earthquakes. Only shallow earthquakes and recordings corresponding to stations with measured V s30 properties are selected. Three basics input parameters are chosen: the moment magnitude ( Mw), the Joyner-Boore distance ( R JB) and V s30. ANFIS model output is the peak ground acceleration (PGA), peak ground velocity (PGV) and 5% damped pseudo-spectral acceleration (PSA) at periods from 0.01 to 4 s. A procedure similar to the random-effects approach is developed to provide between- and within-event standard deviations. The total standard deviation (SD) varies between [0.303 and 0.360] (log10 units) depending on the period. The ground motion predictions resulting from such simple three explanatory variables ANFIS models are shown to be comparable to the most recent NGA results (e.g., Boore et al., in Earthquake Spectra 30:1057-1085, 2014; Derras et al., in Earthquake Spectra 32:2027-2056, 2016). The main advantage of ANFIS compared to artificial neuronal network (ANN) is its simple and one-off topology: five layers. Our results exhibit a number of physically sound features: magnitude scaling of the distance dependency, near-fault saturation distance increasing with magnitude and amplification on soft soils. The ability to implement ANFIS model using an analytic equation and Excel is demonstrated.

  14. Modeling Nonlinear Site Response Uncertainty in Broadband Ground Motion Simulations for the Los Angeles Basin

    Science.gov (United States)

    Assimaki, D.; Li, W.; Steidl, J. M.; Schmedes, J.

    2007-12-01

    source parameters for the ensemble of site conditions. Elastic, equivalent linear and nonlinear simulations are implemented for the deterministic description of the base-model velocity and attenuation structures and nonlinear soil properties, to examine the variability in ground motion predictions as a function of ground motion amplitude and frequency content, and nonlinear site response methodology. The modeling site response uncertainty introduced in the broadband ground motion predictions is reported by means of the COV of site amplification, defined as the ratio of the predicted peak ground acceleration (PGA) and spectral acceleration (SA) at short and long periods to the corresponding intensity measure on the ground surface of a typical NEHRP BC boundary profile (Vs30=760m/s), for the ensemble of approximate and incremental nonlinear models implemented. A frequency index is developed to describe the frequency content of incident ground motion. In conjunction with the rock-outcrop acceleration level, this index is used to identify the site and ground motion conditions where incremental nonlinear analyses should be employed in lieu of approximate methodologies. Finally, the effects of modeling uncertainty in ground response analysis is evaluated in the estimation of site amplification factors, which are successively compared to recently published factors of the New Generation Attenuation Relations (NGA) and the currently employed Seismic Code Provisions (NEHRP).

  15. Can Accelerators Accelerate Learning?

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  16. Can Accelerators Accelerate Learning?

    Science.gov (United States)

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

    2009-03-01

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

  17. Analysis of the Source and Ground Motions from the 2017 M8.2 Tehuantepec and M7.1 Puebla Earthquakes

    Science.gov (United States)

    Melgar, D.; Sahakian, V. J.; Perez-Campos, X.; Quintanar, L.; Ramirez-Guzman, L.; Spica, Z.; Espindola, V. H.; Ruiz-Angulo, A.; Cabral-Cano, E.; Baltay, A.; Geng, J.

    2017-12-01

    The September 2017 Tehuantepec and Puebla earthquakes were intra-slab earthquakes that together caused significant damage in broad regions of Mexico, including the states of Oaxaca, Chiapas, Morelos, Puebla, Mexico, and Mexico City. Ground motions in Mexico City have approximately the same angle of incidence from both earthquakes and potentially sample similar paths close to the city. We examine site effects and source terms by analysis of residuals between Ground-Motion Prediction Equations (GMPEs) and observed ground motions for both of these events at stations from the Servicio Sismólogico Nacional, Instituto de Ingeniería, and the Instituto de Geofísica Red del Valle de Mexico networks. GMPEs are a basis for seismic design, but also provide median ground motion values to act as a basis for comparison of individual earthquakes and site responses. First, we invert for finite-fault slip inversions for Tehuantepec with high-rate GPS, static GPS, tide gauge and DART buoy data, and for Puebla with high-rate GPS and strong motion data. Using the distance from the stations with ground motion observations to the derived slip models, we use the GMPEs of Garcia et al. (2005), Zhao et al. (2006), and Abrahamson, Silva and Kamai (2014), to compute predicted values of peak ground acceleration and velocity (PGA and PGV) and response spectral accelerations (SA). Residuals between observed and predicted ground motion parameters are then computed for each recording, and are decomposed into event and site components using a mixed effects regression. We analyze these residuals as an adjustment away from median ground motions in the region to glean information about the earthquake source properties, as well as local site response in and outside of the Mexico City basin. The event and site terms are then compared with available values of stress drop for the two earthquakes, and Vs30 values for the sites, respectively. This analysis is useful in determining which GMPE is most

  18. Plasma accelerators

    International Nuclear Information System (INIS)

    Bingham, R.; Angelis, U. de; Johnston, T.W.

    1991-01-01

    Recently attention has focused on charged particle acceleration in a plasma by a fast, large amplitude, longitudinal electron plasma wave. The plasma beat wave and plasma wakefield accelerators are two efficient ways of producing ultra-high accelerating gradients. Starting with the plasma beat wave accelerator (PBWA) and laser wakefield accelerator (LWFA) schemes and the plasma wakefield accelerator (PWFA) steady progress has been made in theory, simulations and experiments. Computations are presented for the study of LWFA. (author)

  19. Linear Accelerators

    International Nuclear Information System (INIS)

    Vretenar, M

    2014-01-01

    The main features of radio-frequency linear accelerators are introduced, reviewing the different types of accelerating structures and presenting the main characteristics aspects of linac beam dynamics

  20. Swedish earthquakes and acceleration probabilities

    International Nuclear Information System (INIS)

    Slunga, R.

    1979-03-01

    A method to assign probabilities to ground accelerations for Swedish sites is described. As hardly any nearfield instrumental data is available we are left with the problem of interpreting macroseismic data in terms of acceleration. By theoretical wave propagation computations the relation between seismic strength of the earthquake, focal depth, distance and ground accelerations are calculated. We found that most Swedish earthquake of the area, the 1904 earthquake 100 km south of Oslo, is an exception and probably had a focal depth exceeding 25 km. For the nuclear power plant sites an annual probability of 10 -5 has been proposed as interesting. This probability gives ground accelerations in the range 5-20 % for the sites. This acceleration is for a free bedrock site. For consistency all acceleration results in this study are given for bedrock sites. When applicating our model to the 1904 earthquake and assuming the focal zone to be in the lower crust we get the epicentral acceleration of this earthquake to be 5-15 % g. The results above are based on an analyses of macrosismic data as relevant instrumental data is lacking. However, the macroseismic acceleration model deduced in this study gives epicentral ground acceleration of small Swedish earthquakes in agreement with existent distant instrumental data. (author)

  1. Accelerator Service

    International Nuclear Information System (INIS)

    Champelovier, Y.; Ferrari, M.; Gardon, A.; Hadinger, G.; Martin, J.; Plantier, A.

    1998-01-01

    Since the cessation of the operation of hydrogen cluster accelerator in July 1996, four electrostatic accelerators were in operation and used by the peri-nuclear teams working in multidisciplinary collaborations. These are the 4 MV Van de Graaff accelerator, 2,5 MV Van de Graaff accelerator, 400 kV ion implanter as well as the 120 kV isotope separator

  2. Estimating the upper limit of prehistoric peak ground acceleration using an in situ, intact and vulnerable stalagmite from Plavecká priepast cave (Detrekői-zsomboly), Little Carpathians, Slovakia—first results

    Science.gov (United States)

    Gribovszki, K.; Kovács, K.; Mónus, P.; Bokelmann, G.; Konecny, P.; Lednická, M.; Moseley, G.; Spötl, C.; Edwards, R. L.; Bednárik, M.; Brimich, L.; Tóth, L.

    2017-09-01

    Earthquakes hit urban centres in Europe infrequently, but occasionally with disastrous effects. Obtaining an unbiased view of seismic hazard (and risk) is therefore very important. In principle, the best way to test probabilistic seismic hazard assessments (PSHAs) is to compare them with observations that are entirely independent of the procedure used to produce PSHA models. Arguably, the most valuable information in this context should be information on long-term hazard, namely maximum intensities (or magnitudes) occurring over time intervals that are at least as long as a seismic cycle. The new observations can provide information of maximum intensity (or magnitude) for long timescale as an input data for PSHA studies as well. Long-term information can be gained from intact stalagmites in natural caves. These formations survived all earthquakes that have occurred over thousands of years, depending on the age of the stalagmite. Their `survival' requires that the horizontal ground acceleration (HGA) has never exceeded a certain critical value within that time period. Here, we present such a stalagmite-based case study from the Little Carpathians of Slovakia. A specially shaped, intact and vulnerable stalagmite in the Plavecká priepast cave was examined in 2013. This stalagmite is suitable for estimating the upper limit of horizontal peak ground acceleration generated by prehistoric earthquakes. The critical HGA values as a function of time going back into the past determined from the stalagmite that we investigated are presented. For example, at the time of Jókő event (1906), the critical HGA value cannot have been higher than 1 and 1.3 m/s2 at the time of the assumed Carnuntum event (˜340 AD), and 3000 years ago, it must have been lower than 1.7 m/s2. We claimed that the effect of Jókő earthquake (1906) on the location of the Plavecká priepast cave is consistent with the critical HGA value provided by the stalagmite we investigated. The approach used in

  3. Accelerator requirments for strategic defense

    International Nuclear Information System (INIS)

    Gullickson, R.L.

    1987-01-01

    The authors discuss how directed energy applications require accelerators with high brightness and large gradients to minimize size and weight for space systems. Several major directed energy applications are based upon accelerator technology. The radio-frequency linear accelerator is the basis for both space-based neutral particle beam (NPB) and free electron laser (FEL) devices. The high peak current of the induction linac has made it a leading candidate for ground based free electron laser applications

  4. Stochastic ground motion simulation

    Science.gov (United States)

    Rezaeian, Sanaz; Xiaodan, Sun; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan

    2014-01-01

    Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

  5. Electrical Ground System Design of PEFP

    International Nuclear Information System (INIS)

    Mun, Kyeong Jun; Jeon, Gye Po; Park, Sung Sik; Min, Yi Sub; Nam, Jung Min; Cho, Jang Hyung; Kim, Jun Yeon

    2010-01-01

    Since host site host site was selected Gyeong-ju city in January, 2006. we need design revision of Proton Accelerator research center to reflect on host site characteristics and several conditions. In this paper, electrical grounding and lightning protection design scheme is introduced. In electrical grounding system design of PEFP, we classified electrical facilities into 4 groups; equipment grounding (type A), instrument grounding (Type A), high frequency instrument grounding (Type C) and lightning arrestor grounding (Type D). Lightning protection system is designed in all buildings of proton accelerator research center of PEFP, including switchyard

  6. Electrical Ground System Design of PEFP

    Energy Technology Data Exchange (ETDEWEB)

    Mun, Kyeong Jun; Jeon, Gye Po; Park, Sung Sik; Min, Yi Sub; Nam, Jung Min; Cho, Jang Hyung; Kim, Jun Yeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    Since host site host site was selected Gyeong-ju city in January, 2006. we need design revision of Proton Accelerator research center to reflect on host site characteristics and several conditions. In this paper, electrical grounding and lightning protection design scheme is introduced. In electrical grounding system design of PEFP, we classified electrical facilities into 4 groups; equipment grounding (type A), instrument grounding (Type A), high frequency instrument grounding (Type C) and lightning arrestor grounding (Type D). Lightning protection system is designed in all buildings of proton accelerator research center of PEFP, including switchyard

  7. Future accelerators (?)

    Energy Technology Data Exchange (ETDEWEB)

    John Womersley

    2003-08-21

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

  8. Hazard-to-Risk: High-Performance Computing Simulations of Large Earthquake Ground Motions and Building Damage in the Near-Fault Region

    Science.gov (United States)

    Miah, M.; Rodgers, A. J.; McCallen, D.; Petersson, N. A.; Pitarka, A.

    2017-12-01

    We are running high-performance computing (HPC) simulations of ground motions for large (magnitude, M=6.5-7.0) earthquakes in the near-fault region (steel moment frame buildings throughout the near-fault domain. For ground motions, we are using SW4, a fourth order summation-by-parts finite difference time-domain code running on 10,000-100,000's of cores. Earthquake ruptures are generated using the Graves and Pitarka (2017) method. We validated ground motion intensity measurements against Ground Motion Prediction Equations. We considered two events (M=6.5 and 7.0) for vertical strike-slip ruptures with three-dimensional (3D) basin structures, including stochastic heterogeneity. We have also considered M7.0 scenarios for a Hayward Fault rupture scenario which effects the San Francisco Bay Area and northern California using both 1D and 3D earth structure. Dynamic, inelastic response of canonical buildings is computed with the NEVADA, a nonlinear, finite-deformation finite element code. Canonical buildings include 3-, 9-, 20- and 40-story steel moment frame buildings. Damage potential is tracked by the peak inter-story drift (PID) ratio, which measures the maximum displacement between adjacent floors of the building and is strongly correlated with damage. PID ratios greater 1.0 generally indicate non-linear response and permanent deformation of the structure. We also track roof displacement to identify permanent deformation. PID (damage) for a given earthquake scenario (M, slip distribution, hypocenter) is spatially mapped throughout the SW4 domain with 1-2 km resolution. Results show that in the near fault region building damage is correlated with peak ground velocity (PGV), while farther away (> 20 km) it is better correlated with peak ground acceleration (PGA). We also show how simulated ground motions have peaks in the response spectra that shift to longer periods for larger magnitude events and for locations of forward directivity, as has been reported by

  9. NGA-West 2 Equations for predicting PGA, PGV, and 5%-Damped PSA for shallow crustal earthquakes

    Science.gov (United States)

    Boore, David M.; Stewart, Jon P.; Seyhan, Emel; Atkinson, Gail M.

    2013-01-01

    We provide ground-motion prediction equations for computing medians and standard deviations of average horizontal component intensity measures (IMs) for shallow crustal earthquakes in active tectonic regions. The equations were derived from a global database with M 3.0–7.9 events. We derived equations for the primary M- and distance-dependence of the IMs after fixing the VS30-based nonlinear site term from a parallel NGA-West 2 study. We then evaluated additional effects using mixed effects residuals analysis, which revealed no trends with source depth over the M range of interest, indistinct Class 1 and 2 event IMs, and basin depth effects that increase and decrease long-period IMs for depths larger and smaller, respectively, than means from regional VS30-depth relations. Our aleatory variability model captures decreasing between-event variability with M, as well as within-event variability that increases or decreases with M depending on period, increases with distance, and decreases for soft sites.

  10. Interdependence between damage indices and ground motion parameters based on Hilbert–Huang transform

    International Nuclear Information System (INIS)

    Alvanitopoulos, P F; Andreadis, I; Elenas, A

    2010-01-01

    Feature extraction from seismic accelerograms is a key issue in characterization of earthquake damage in structures. Until today, a number of effective classical parameters such as peak ground acceleration (PGA) and Arias intensity have been proposed for analyzing the earthquake motion records. The aim of this paper is to search for new crucial characteristic seismic parameters which provide information pertinent to the damage indicators of the structures. The first proposed parameter is the maximum amplitude (A HHT m ax ) and the second is the mean amplitude (A HHT m ean ). Emphasis of our work has been placed on the use of the Hilbert–Huang transform (HHT). A set of 13 natural accelerograms from worldwide well-known sites with strong seismic activity have been used. The HHT has been applied to the nonlinear and non-stationary data (earthquake recordings). Each complex seismic accelerogram is decomposed into several simple components called intrinsic mode functions (IMFs). Using the IMFs a three-dimensional time–frequency distribution of earthquake excitation is computed and two new seismic parameters are proposed and evaluated. After the numerical computation of all the seismic parameters (classical and proposed), nonlinear dynamic analysis is carried out to provide the post-seismic damage status of the structure under study. Two structural damage indices are utilized and the degree of interrelation among them and the seismic parameters is provided by correlation coefficients. Furthermore, two different reinforced concrete structures are examined. Results indicate the high correlation of the new seismic parameters (A HHT m ax , A HHT m ean ) with the damage indices and confirm that HHT is a promising tool for extracting information to characterize damage in structures

  11. Electrostatic accelerators

    OpenAIRE

    Hinterberger, F

    2006-01-01

    The principle of electrostatic accelerators is presented. We consider Cockcroft– Walton, Van de Graaff and Tandem Van de Graaff accelerators. We resume high voltage generators such as cascade generators, Van de Graaff band generators, Pelletron generators, Laddertron generators and Dynamitron generators. The speci c features of accelerating tubes, ion optics and methods of voltage stabilization are described. We discuss the characteristic beam properties and the variety of possible beams. We ...

  12. Electrostatic accelerators

    CERN Document Server

    Hinterberger, F

    2006-01-01

    The principle of electrostatic accelerators is presented. We consider Cockcroft– Walton, Van de Graaff and Tandem Van de Graaff accelerators. We resume high voltage generators such as cascade generators, Van de Graaff band generators, Pelletron generators, Laddertron generators and Dynamitron generators. The speci c features of accelerating tubes, ion optics and methods of voltage stabilization are described. We discuss the characteristic beam properties and the variety of possible beams. We sketch possible applications and the progress in the development of electrostatic accelerators.

  13. Accelerator development

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Because the use of accelerated heavy ions would provide many opportunities for new and important studies in nuclear physics and nuclear chemistry, as well as other disciplines, both the Chemistry and Physics Divisions are supporting the development of a heavy-ion accelerator. The design of greatest current interest includes a tandem accelerator with a terminal voltage of approximately 25 MV injecting into a linear accelerator with rf superconducting resonators. This combined accelerator facility would be capable of accelerating ions of masses ranging over the entire periodic table to an energy corresponding to approximately 10 MeV/nucleon. This approach, as compared to other concepts, has the advantages of lower construction costs, lower operating power, 100 percent duty factor, and high beam quality (good energy resolution, good timing resolution, small beam size, and small beam divergence). The included sections describe the concept of the proposed heavy-ion accelerator, and the development program aiming at: (1) investigation of the individual questions concerning the superconducting accelerating resonators; (2) construction and testing of prototype accelerator systems; and (3) search for economical solutions to engineering problems. (U.S.)

  14. RECIRCULATING ACCELERATION

    International Nuclear Information System (INIS)

    BERG, J.S.; GARREN, A.A.; JOHNSTONE, C.

    2000-01-01

    This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous

  15. LIBO accelerates

    CERN Multimedia

    2002-01-01

    The prototype module of LIBO, a linear accelerator project designed for cancer therapy, has passed its first proton-beam acceleration test. In parallel a new version - LIBO-30 - is being developed, which promises to open up even more interesting avenues.

  16. Accelerating Inspire

    CERN Document Server

    AUTHOR|(CDS)2266999

    2017-01-01

    CERN has been involved in the dissemination of scientific results since its early days and has continuously updated the distribution channels. Currently, Inspire hosts catalogues of articles, authors, institutions, conferences, jobs, experiments, journals and more. Successful orientation among this amount of data requires comprehensive linking between the content. Inspire has lacked a system for linking experiments and articles together based on which accelerator they were conducted at. The purpose of this project has been to create such a system. Records for 156 accelerators were created and all 2913 experiments on Inspire were given corresponding MARC tags. Records of 18404 accelerator physics related bibliographic entries were also tagged with corresponding accelerator tags. Finally, as a part of the endeavour to broaden CERN's presence on Wikipedia, existing Wikipedia articles of accelerators were updated with short descriptions and links to Inspire. In total, 86 Wikipedia articles were updated. This repo...

  17. Grounded theory.

    Science.gov (United States)

    Harris, Tina

    2015-04-29

    Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it. It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read.

  18. Characterization of earthquake-induced ground motion from the L'Aquila seismic sequence of 2009, Italy

    Science.gov (United States)

    Malagnini, Luca; Akinci, Aybige; Mayeda, Kevin; Munafo', Irene; Herrmann, Robert B.; Mercuri, Alessia

    2011-01-01

    Based only on weak-motion data, we carried out a combined study on region-specific source scaling and crustal attenuation in the Central Apennines (Italy). Our goal was to obtain a reappraisal of the existing predictive relationships for the ground motion, and to test them against the strong-motion data [peak ground acceleration (PGA), peak ground velocity (PGV) and spectral acceleration (SA)] gathered during the Mw 6.15 L'Aquila earthquake (2009 April 6, 01:32 UTC). The L'Aquila main shock was not part of the predictive study, and the validation test was an extrapolation to one magnitude unit above the largest earthquake of the calibration data set. The regional attenuation was determined through a set of regressions on a data set of 12 777 high-quality, high-gain waveforms with excellent S/N ratios (4259 vertical and 8518 horizontal time histories). Seismograms were selected from the recordings of 170 foreshocks and aftershocks of the sequence (the complete set of all earthquakes with ML≥ 3.0, from 2008 October 1 to 2010 May 10). All waveforms were downloaded from the ISIDe web page (), a web site maintained by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). Weak-motion data were used to obtain a moment tensor solution, as well as a coda-based moment-rate source spectrum, for each one of the 170 events of the L'Aquila sequence (2.8 ≤Mw≤ 6.15). Source spectra were used to verify the good agreement with the source scaling of the Colfiorito seismic sequence of 1997-1998 recently described by Malagnini (2008). Finally, results on source excitation and crustal attenuation were used to produce the absolute site terms for the 23 stations located within ˜80 km of the epicentral area. The complete set of spectral corrections (crustal attenuation and absolute site effects) was used to implement a fast and accurate tool for the automatic computation of moment magnitudes in the Central Apennines.

  19. Regeneração óssea guiada com o uso de membrana de copolímero PLA/PGA em levantamento da membrana do seio maxilar: estudo experimental com análises histomorfométrica e imunoistoquímica

    OpenAIRE

    Bomfim, Bianca Bravim [UNESP

    2015-01-01

    A utilização de biomateriais em implantodontia, principalmente em casos em que o leito receptor do implante apresenta quantidade e qualidade ósseas inadequadas, se torna importante. Diversos estudos mostram a possibilidade do usar copolímeros de PLA/PGA, no entanto, estes mesmos estudos mostram que a proporção de PLA e PGA irá influenciar a taxa de degradação do copolímero. Portanto, objetivo desse estudo foi avaliar o comportamento biológico do copolímero de PLA/PGA como substitutos ósseos p...

  20. Pretreatment with platelet derived growth factor-BB modulates the ability of costochondral resting zone chondrocytes incorporated into PLA/PGA scaffolds to form new cartilage in vivo.

    Science.gov (United States)

    Lohmann, C H; Schwartz, Z; Niederauer, G G; Carnes, D L; Dean, D D; Boyan, B D

    2000-01-01

    Optimal repair of chondral defects is likely to require both a suitable population of chondrogenic cells and a biodegradable matrix to provide a space-filling structural support during the early stages of cartilage formation. This study examined the ability of chondrocytes to support cartilage formation when incorporated into biodegradable scaffolds constructed from copolymers (PLG) of polylactic acid (PLA) and polyglycolic acid (PGA) and implanted in the calf muscle of nude mice. Scaffolds were fabricated to be more hydrophilic (PLG-H) or were reinforced with 10% PGA fibers (PLG-FR), increasing the stiffness of the implant by 20-fold. Confluent primary cultures of rat costochondral resting zone chondrocytes (RC) were loaded into PLG-H foams and implanted intramuscularly. To determine if growth factor pretreatment could modulate the ability of the cells to form new cartilage, RC cells were pretreated with recombinant human platelet derived growth factor-BB IPDGF-BB) for 4 or 24 h prior to implantation. To assess whether scaffold material properties could affect the ability of chondrogenic cells to form cartilage, RC cells were also loaded into PLG-FR scaffolds. To determine if the scaffolds or treatment with PDGF-BB affected the rate of chondrogenesis, tissue at the implant site was harvested at four and eight weeks post-operatively, fixed, decalcified and embedded in paraffin. Sections were obtained along the transverse plane of the lower leg, stained with haematoxylin and eosin, and then assessed by morphometric analysis for area of cartilage, area of residual implant, and area of fibrous connective tissue formation (fibrosis). Whether or not the cartilage contained hypertrophic cells was also assessed. The amount of residual implant did not change with time in any of the implanted tissues. The area occupied by PLG-FR implants was greater than that occupied by PLG-H implants at both time points. All implants were surrounded by fibrous connective tissue, whether

  1. Estimation of Seismic Ground Motions and Attendant Potential Human Fatalities from Scenario Earthquakes on the Chishan Fault in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Kun-Sung Liu

    2017-01-01

    Full Text Available The purpose of this study is to estimate maximum ground motions in southern Taiwan as well as to assess potential human fatalities from scenario earthquakes on the Chishan active faults in this area. The resultant Shake Map patterns of maximum ground motion in a case of Mw 7.2 show the areas of PGA above 400 gals are located in the northeastern, central and northern parts of southwestern Kaohsiung as well as the southern part of central Tainan, as shown in the regions inside the yellow lines in the corresponding figure. Comparing cities with similar distances located in Tainan, Kaohsiung, and Pingtung to the Chishan fault, the cities in Tainan area have relatively greater PGA and PGV, due to large site response factors in Tainan area. Furthermore, seismic hazards in terms of PGA and PGV in the vicinity of the Chishan fault are not completely dominated by the Chishan fault. The main reason is that some areas located in the vicinity of the Chishan fault are marked with low site response amplification values from 0.55 - 1.1 and 0.67 - 1.22 for PGA and PGV, respectively. Finally, from estimation of potential human fatalities from scenario earthquakes on the Chishan active fault, it is noted that potential fatalities increase rapidly in people above age 45. Total fatalities reach a high peak in age groups of 55 - 64. Another to pay special attention is Kaohsiung City has more than 540 thousand households whose residences over 50 years old. In light of the results of this study, I urge both the municipal and central governments to take effective seismic hazard mitigation measures in the highly urbanized areas with a large number of old buildings in southern Taiwan.

  2. FMIT accelerator

    International Nuclear Information System (INIS)

    Armstrong, D.D.

    1983-01-01

    A 35-MeV 100-mA cw linear accelerator is being designed by Los Alamos for use in the Fusion Materials Irradiation Test (FMIT) Facility. Essential to this program is the design, construction, and evaluation of performance of the accelerator's injector, low-energy beam transport, and radio-frequency quadrupole sections before they are shipped to the facility site. The installation and testing of some of these sections have begun as well as the testing of the rf, noninterceptive beam diagnostics, computer control, dc power, and vacuum systems. An overview of the accelerator systems and the performance to date is given

  3. Electron accelerator

    International Nuclear Information System (INIS)

    Abramyan.

    1981-01-01

    The USSR produces an electron accelerator family of a simple design powered straight from the mains. The specifications are given of accelerators ELITA-400, ELITA-3, ELT-2, TEUS-3 and RIUS-5 with maximum electron energies of 0.3 to 5 MeV, a mean power of 10 to 70 kW operating in both the pulsed and the continuous (TEUS-3) modes. Pulsed accelerators ELITA-400 and ELITA-3 and RIUS-5 in which TESLA resonance transformers are used are characterized by their compact size. (Ha)

  4. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  5. Acceleration theorems

    International Nuclear Information System (INIS)

    Palmer, R.

    1994-06-01

    Electromagnetic fields can be separated into near and far components. Near fields are extensions of static fields. They do not radiate, and they fall off more rapidly from a source than far fields. Near fields can accelerate particles, but the ratio of acceleration to source fields at a distance R, is always less than R/λ or 1, whichever is smaller. Far fields can be represented as sums of plane parallel, transversely polarized waves that travel at the velocity of light. A single such wave in a vacuum cannot give continuous acceleration, and it is shown that no sums of such waves can give net first order acceleration. This theorem is proven in three different ways; each method showing a different aspect of the situation

  6. LINEAR ACCELERATOR

    Science.gov (United States)

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  7. Earthquake-induced soft-sediment deformations and seismically amplified erosion rates recorded in varved sediments of Köyceğiz Lake (SW Turkey)

    KAUST Repository

    Avsar, Ulas; Jonsson, Sigurjon; Avşar, Ö zgü r; Schmidt, Sabine

    2016-01-01

    sequence of Köyceğiz Lake (SW Turkey) that we compare with estimated peak ground acceleration (PGA) values of several nearby earthquakes. We find that earthquakes exceeding estimated PGA values of ca. 20 cm/s2 can induce soft-sediment deformations (SSD

  8. Journal of Earth System Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Effects of nonlinear soil structure interaction (SSI) were also considered by using interface elements. This parametric study evaluates the effects of soil type, structure weight, liquefiable soil layer thickness, event parameters (e.g., moment magnitude of earthquake (), peak ground acceleration PGA, PGV/PGA ratio and the ...

  9. Accelerator Technology Division progress report, FY 1992

    International Nuclear Information System (INIS)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations

  10. Accelerator Technology Division annual report, FY 1991

    International Nuclear Information System (INIS)

    1992-04-01

    This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; Φ Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations

  11. Accelerator Technology Division progress report, FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  12. Commissioning the GTA accelerator

    International Nuclear Information System (INIS)

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Connolly, R.; Weiss, R.; Saadatmand, K.

    1992-01-01

    The Ground Test Accelerator (GTA) is being used to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H - beam and then neutralizing it. The goal is to produce a 24 MeV, 50 mA device with a 2% duty factor. Specific features of the GTA -- injector, beam optics, rf linac structures, diagnostics, control and rf power systems are described. The first four steps in commissioning have been completed. The RFQ predicted and measured performances are in good agreement; however, the transmission is lower than specifications. Input emittance is larger than design specifications and increases the effects of image charge and multipoles. Displacement of steering magnets in either the horizontal or vertical plane caused beam displacements in both planes. It is suspected that quadrupole rotation is the cause of the coupled motion. 9 figs., 5 tabs., 11 refs

  13. Commissioning the GTA accelerator

    International Nuclear Information System (INIS)

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.; Saadatmand, K.

    1992-01-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth's magnetic field and travel in straight lines unless they enter the earth's atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H - beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor

  14. Accelerator microanalysis

    International Nuclear Information System (INIS)

    Tuniz, C.

    1997-01-01

    Particle accelerators have been developed more than sixty years ago to investigate nuclear and atomic phenomena. A major shift toward applications of accelerators in the study of materials structure and composition in inter-disciplinary projects has been witnessed in the last two decades. The Australian Nuclear Science and Technology Organisation (ANSTO) has developed advanced research programs based on the use of particle and photon beams. Atmospheric pollution problems are investigated at the 3 MV Van de Graff accelerator using ion beam analysis techniques to detect toxic elements in aerosol particles. High temperature superconductor and semiconductor materials are characterised using the recoil of iodine and other heavy ions produced at ANTARES, the 10-MV Tandem accelerator. A heavy-ion microprobe is presently being developed at ANTARES to map elemental concentrations of specific elements with micro-size resolution. An Accelerator mass Spectrometry (AMS) system has been developed at ANSTO for the ultra-sensitive detection of Carbon-14, Iodine-129 and other long-lived radioisotopes. This AMS spectrometer is a key instrument for climate change studies and international safeguards. ANSTO is also managing the Australian Synchrotron Research program based on facilities developed at the Photon Factory (Japan) and at the Advanced Photon Source (USA). Advanced projects in biology, materials chemistry, structural condensed matter and other disciplines are being promoted by a consortium involving Australian universities and research institutions. This paper will review recent advances in the use of particle accelerators, with a particular emphasis on applications developed at ANSTO and related to problems of international concern, such as global environmental change, public health and nuclear proliferation

  15. Accelerator Technology Division progress report, FY 1993

    International Nuclear Information System (INIS)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-01-01

    This report discusses the following topics: A Next-Generation Spallation-Neutron Source; Accelerator Performance Demonstration Facility; APEX Free-Electron Laser Project; The Ground Test Accelerator (GTA) Program; Intense Neutron Source for Materials Testing; Linac Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Radio-Frequency Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operation

  16. Development of bipolar pulse accelerator for intense pulsed ion beam acceleration

    International Nuclear Information System (INIS)

    Fujioka, Y.; Mitsui, C.; Kitamura, I.; Takahashi, T.; Masugata, K.; Tanoue, H.; Arai, K.

    2003-01-01

    To improve the purity of an intense pulsed ion beams a new type of pulsed ion beam accelerator named 'bipolar pulse accelerator (BPA)' was proposed. In the accelerator purity of the beam is expected. To confirm the principle of the accelerator experimental system was developed. The system utilizes B y type magnetically insulated acceleration gap and operated with single polar negative pulse. A coaxial gas puff plasma gun placed in the grounded anode was used as an ion source, and source plasma (nitrogen) of current density approx. = 25 A/cm 2 , duration approx. = 1.5 μs was injected into the acceleration gap. The ions are successfully accelerated from the grounded anode to the drift tube by applying negative pulse of voltage 180 kV, duration 60 ns to the drift tube. Pulsed ion beam of current density approx. = 40 A/cm 2 , duration approx. 60 ns was obtained at 42 mm downstream from the anode surface. (author)

  17. Accelerator operations

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    This section is concerned with the operation of both the tandem-linac system and the Dynamitron, two accelerators that are used for entirely different research. Developmental activities associated with the tandem and the Dynamitron are also treated here, but developmental activities associated with the superconducting linac are covered separately because this work is a program of technology development in its own right

  18. CNSTN Accelerator

    International Nuclear Information System (INIS)

    Habbassi, Afifa; Trabelsi, Adel

    2010-01-01

    This project give a big idea about the measurement of the linear accelerator in the CNSTN. During this work we control dose distribution for different product. For this characterisation we have to make an installation qualification ,operational qualification,performance qualification and of course for every step we have to control temperature and the dose ,even the distribution of the last one.

  19. Accelerators course

    CERN Multimedia

    CERN. Geneva HR-RFA; Métral, E

    2006-01-01

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges

  20. Accelerator operations

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Operations of the SuperHILAC, the Bevatron/Bevalac, and the 184-inch Synchrocyclotron during the period from October 1977 to September 1978 are discussed. These include ion source development, accelerator facilities, the Heavy Ion Spectrometer System, and Bevelac biomedical operations

  1. Accelerator update

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    When the Accelerator Conference, combined International High Energy and US Particle versions, held in Dallas in May, was initially scheduled, progress nearby for the US Superconducting Supercollider was high on the preliminary agenda. With the SSC voted down by Congress in October 1993, this was no longer the case. However the content of the meeting, in terms of both its deep implications for ambitious new projects and the breadth of its scope, showed that the worldwide particle accelerator field is far from being moribund. A traditional feature of such accelerator conferences is the multiplicity of parallel sessions. No one person can attend all sessions, so that delegates can follow completely different paths and emerge with totally different impressions. Despite this overload, and despite the SSC cancellation, the general picture is one of encouraging progress over a wide range of major new projects throughout the world. At the same time, spinoff from, and applications of, accelerators and accelerator technology are becoming increasingly important. Centrestage is now CERN's LHC proton-proton collider, where a test string of superconducting magnets is operating over long periods at the nominal LHC field of 8.36 tesla or more. The assignment of the underground areas in the existing 27- kilometre LEP tunnel is now quasidefinitive (see page 3). For CERN's existing big machine, the LEP electron-positron collider, ongoing work concentrates on boosting performance using improved optics and bunch trains. But the main objective is the LEP2 scheme using superconducting accelerating cavities to boost the beam energy (see page 6). After some initial teething problems, production and operation of these cavities appears to have been mastered, at least under test conditions. A highlight at CERN last year was the first run with lead ions (December 1994, page 15). Handling these heavy particles with systems originally designed for protons calls for ingenuity. The SPS

  2. Accelerator update

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-09-15

    When the Accelerator Conference, combined International High Energy and US Particle versions, held in Dallas in May, was initially scheduled, progress nearby for the US Superconducting Supercollider was high on the preliminary agenda. With the SSC voted down by Congress in October 1993, this was no longer the case. However the content of the meeting, in terms of both its deep implications for ambitious new projects and the breadth of its scope, showed that the worldwide particle accelerator field is far from being moribund. A traditional feature of such accelerator conferences is the multiplicity of parallel sessions. No one person can attend all sessions, so that delegates can follow completely different paths and emerge with totally different impressions. Despite this overload, and despite the SSC cancellation, the general picture is one of encouraging progress over a wide range of major new projects throughout the world. At the same time, spinoff from, and applications of, accelerators and accelerator technology are becoming increasingly important. Centrestage is now CERN's LHC proton-proton collider, where a test string of superconducting magnets is operating over long periods at the nominal LHC field of 8.36 tesla or more. The assignment of the underground areas in the existing 27- kilometre LEP tunnel is now quasidefinitive (see page 3). For CERN's existing big machine, the LEP electron-positron collider, ongoing work concentrates on boosting performance using improved optics and bunch trains. But the main objective is the LEP2 scheme using superconducting accelerating cavities to boost the beam energy (see page 6). After some initial teething problems, production and operation of these cavities appears to have been mastered, at least under test conditions. A highlight at CERN last year was the first run with lead ions (December 1994, page 15). Handling these heavy particles with systems originally designed for protons calls for ingenuity. The SPS has managed

  3. Analysis of K-net and Kik-net data: implications for ground motion prediction - acceleration time histories, response spectra and nonlinear site response; Analyse des donnees accelerometriques de K-net et Kik-net: implications pour la prediction du mouvement sismique - accelerogrammes et spectres de reponse - et la prise en compte des effets de site non-lineaire

    Energy Technology Data Exchange (ETDEWEB)

    Pousse, G

    2005-10-15

    This thesis intends to characterize ground motion during earthquake. This work is based on two Japanese networks. It deals with databases of shallow events, depth less than 25 km, with magnitude between 4.0 and 7.3. The analysis of K-net allows to compute a spectral ground motion prediction equation and to review the shape of the Eurocode 8 design spectra. We show the larger amplification at short period for Japanese data and bring in light the soil amplification that takes place at large period. In addition, we develop a new empirical model for simulating synthetic stochastic nonstationary acceleration time histories. By specifying magnitude, distance and site effect, this model allows to produce many time histories, that a seismic event is liable to produce at the place of interest. Furthermore, the study of near-field borehole records of the Kik-net allows to explore the validity domain of predictive equations and to explain what occurs by extrapolating ground motion predictions. Finally, we show that nonlinearity reduces the dispersion of ground motion at the surface. (author)

  4. Accelerating Value Creation with Accelerators

    DEFF Research Database (Denmark)

    Jonsson, Eythor Ivar

    2015-01-01

    and developing the best business ideas and support the due diligence process. Even universities are noticing that the learning experience of the action learning approach is an effective way to develop capabilities and change cultures. Accelerators related to what has historically been associated...

  5. The deadly Morelos-Puebla, Mexico Intraslab Earthquake of 19 September 2017 (Mw7.1): Was the Earthquake Unexpected and Were the Ground Motions and Damage Pattern in Mexico City Abnormal?

    Science.gov (United States)

    Perez-Campos, X.; Singh, S. K.; Arroyo, D.; Cruz-Atienza, V. M.; Ordaz, M.; Hjorleifsdottir, V.; Iglesias, A.

    2017-12-01

    On 19 September 2017, thirty two years after the 1985 Michoacan interplate earthquake (Mw8.0), the city was once again devastated but this time by a Mw7.1 intraslab earthquake. The 2017 earthquake was located near the border of the states of Morelos and Puebla (18.410N, -98.710E; H=57 km), to SSE of Mexico City, at a hypocentral distance of about 127 km. It caused great panic in Mexico City, collapse of 44 buildings, and severely damaged many others. More than 200 persons were killed in the city. It was the second most destructive earthquake in the history of Mexico City, next only to the 1985 earthquake. A strong-motion station at CU located on basalt lava flows on main campus UNAM has been in continuous operation since 1964. PGA of 59 gal at CU during the 2017 earthquake is the largest ever, two times greater than that recorded during the 1985 earthquake (29 gal). The 2017 earthquake raised questions that are critical in fathoming the seismic vulnerability of the city and in its reconstruction. Was such an intraslab earthquake (Mw 7 at a hypocentral distance of 127 km) unexpected? Were the recorded ground motions in the city unusually high for such an earthquake? Why did the damage pattern during the earthquake differ from that observed during the 1985 earthquake? The earthquake was the closest M>5 intraslab earthquake to Mexico City ever recorded. However, Mw 5.9 events have occurred in recent years in the vicinity of the 2017 earthquake (R 145 km). Three Mw≥6.9 earthquakes have occurred since 1964 in the distance range 184-225 km. Thus, Mw and R of the earthquake was not surprising. However, a comparison of Fourier acceleration spectra at CU of 10 intraslab earthquakes with largest PGA, reduced to a common distance of R=127 km, shows that the amplitudes of the 2017 events were abnormally high in 1-2s range. Spectra of intraslab events at CU are enriched at higher frequencies relative to interplate ones because of closer distance, greater depth and higher

  6. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  7. Laser acceleration

    International Nuclear Information System (INIS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-01-01

    The fundamental idea of LaserWakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wake fields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ∼ c and ultra fastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nano materials is also emerging.

  8. Accelerating networks

    International Nuclear Information System (INIS)

    Smith, David M D; Onnela, Jukka-Pekka; Johnson, Neil F

    2007-01-01

    Evolving out-of-equilibrium networks have been under intense scrutiny recently. In many real-world settings the number of links added per new node is not constant but depends on the time at which the node is introduced in the system. This simple idea gives rise to the concept of accelerating networks, for which we review an existing definition and-after finding it somewhat constrictive-offer a new definition. The new definition provided here views network acceleration as a time dependent property of a given system as opposed to being a property of the specific algorithm applied to grow the network. The definition also covers both unweighted and weighted networks. As time-stamped network data becomes increasingly available, the proposed measures may be easily applied to such empirical datasets. As a simple case study we apply the concepts to study the evolution of three different instances of Wikipedia, namely, those in English, German, and Japanese, and find that the networks undergo different acceleration regimes in their evolution

  9. Advanced concepts for acceleration

    International Nuclear Information System (INIS)

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations

  10. Vibration measurement of accelerator tube table in ATF

    International Nuclear Information System (INIS)

    Nakayama, Y.; Sugahara, R.; Yamaoka, H.; Masuzawa, M.; Yamashita, S.

    2004-01-01

    Acceleration tube fixed to the table should not be a structure to amplify the vibration. Stability of ground is preferable for accelerator beam operation, and the beam control by extremely high resolution is especially demanded in GLC. Then, we have measured ground motion and table vibration in ATF at KEK. In this paper, some of analyzed results are shown, and we show the characteristics of vibration about the accelerator tube table in ATF. (author)

  11. Accelerators and the Accelerator Community

    Energy Technology Data Exchange (ETDEWEB)

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  12. Accelerators and the Accelerator Community

    International Nuclear Information System (INIS)

    Malamud, Ernest; Sessler, Andrew

    2008-01-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process

  13. Ground water

    International Nuclear Information System (INIS)

    Osmond, J.K.; Cowart, J.B.

    1982-01-01

    The subject is discussed under the headings: background and theory (introduction; fractionation in the hydrosphere; mobility factors; radioisotope evolution and aquifer classification; aquifer disequilibria and geochemical fronts); case studies (introduction; (a) conservative, and (b) non-conservative, behaviour); ground water dating applications (general requirements; radon and helium; radium isotopes; uranium isotopes). (U.K.)

  14. Ground water

    International Nuclear Information System (INIS)

    Osmond, J.K.; Cowart, J.B.

    1992-01-01

    The great variations in concentrations and activity ratios of 234 U/ 238 U in ground waters and the features causing elemental and isotopic mobility in the hydrosphere are discussed. Fractionation processes and their application to hydrology and other environmental problems such as earthquake, groundwater and aquifer dating are described. (UK)

  15. Ring accelerators

    International Nuclear Information System (INIS)

    Gisler, G.; Faehl, R.

    1983-01-01

    We present two-dimensional simulations in (r-z) and r-theta) cylinderical geometries of imploding-liner-driven accelerators of rings of charged particles. We address issues of azimuthal and longitudinal stability of the rings. We discuss self-trapping designs in which beam injection and extraction is aided by means of external cusp fields. Our simulations are done with the 2-1/2-D particle-in-cell plasma simulation code CLINER, which combines collisionless, electromagnetic PIC capabilities with a quasi-MHD finite element package

  16. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  17. Cosmic ray acceleration mechanisms

    International Nuclear Information System (INIS)

    Cesarsky, C.J.

    1982-09-01

    We present a brief summary of some of the most popular theories of cosmic ray acceleration: Fermi acceleration, its application to acceleration by shocks in a scattering medium, and impulsive acceleration by relativistic shocks

  18. Accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator

    International Nuclear Information System (INIS)

    Surendran, P.; Shrivastava, A.; Gupta, A.K.; Nair, J.P.; Yadav, M.L.; Gore, J.A.; Sparrow, H.; Bhagwat, P.V.; Kailas, S.

    2006-01-01

    Accelerator based mass spectrometry (ABMs) is an ultra sensitive means of counting individual atoms having sufficiently long half life and available in small amount. The 14 U D Pelletron Accelerator is an ideal machine to carry out ABMs studies with heavy isotopes like 36 Cl and 129 I. Cosmogenic radio isotope 36 Cl is widely being detected using ABMs as it has got applications in ground water research, radioactive waste management, atmospheric 36 Cl transport mechanism studies of Arctic Alpine ice core etc. As a part of the ongoing ABMs programme at 14UD Pelletron Accelerator Facility at Mumbai, a segmented gas detector developed for identification of 36 Cl was tested for performance. Recently a beam chopper required for this measurement has been developed. Further progress made in this programme is discussed in this paper. (author)

  19. Ground Pollution Science

    International Nuclear Information System (INIS)

    Oh, Jong Min; Bae, Jae Geun

    1997-08-01

    This book deals with ground pollution science and soil science, classification of soil and fundamentals, ground pollution and human, ground pollution and organic matter, ground pollution and city environment, environmental problems of the earth and ground pollution, soil pollution and development of geological features of the ground, ground pollution and landfill of waste, case of measurement of ground pollution.

  20. Transonic and supersonic ground effect aerodynamics

    Science.gov (United States)

    Doig, G.

    2014-08-01

    A review of recent and historical work in the field of transonic and supersonic ground effect aerodynamics has been conducted, focussing on applied research on wings and aircraft, present and future ground transportation, projectiles, rocket sleds and other related bodies which travel in close ground proximity in the compressible regime. Methods for ground testing are described and evaluated, noting that wind tunnel testing is best performed with a symmetry model in the absence of a moving ground; sled or rail testing is ultimately preferable, though considerably more expensive. Findings are reported on shock-related ground influence on aerodynamic forces and moments in and accelerating through the transonic regime - where force reversals and the early onset of local supersonic flow is prevalent - as well as more predictable behaviours in fully supersonic to hypersonic ground effect flows.

  1. Ground Motion Models for Future Linear Colliders

    International Nuclear Information System (INIS)

    Seryi, Andrei

    2000-01-01

    Optimization of the parameters of a future linear collider requires comprehensive models of ground motion. Both general models of ground motion and specific models of the particular site and local conditions are essential. Existing models are not completely adequate, either because they are too general, or because they omit important peculiarities of ground motion. The model considered in this paper is based on recent ground motion measurements performed at SLAC and at other accelerator laboratories, as well as on historical data. The issues to be studied for the models to become more predictive are also discussed

  2. Measurement of ground motion in various sites

    International Nuclear Information System (INIS)

    Bialowons, W.; Amirikas, R.; Bertolini, A.; Kruecker, D.

    2007-04-01

    Ground vibrations may affect low emittance beam transport in linear colliders, Free Electron Lasers (FEL) and synchrotron radiation facilities. This paper is an overview of a study program to measure ground vibrations in various sites which can be used for site characterization in relation to accelerator design. Commercial broadband seismometers have been used to measure ground vibrations and the resultant database is available to the scientific community. The methodology employed is to use the same equipment and data analysis tools for ease of comparison. This database of ground vibrations taken in 19 sites around the world is first of its kind. (orig.)

  3. Communication grounding facility

    International Nuclear Information System (INIS)

    Lee, Gye Seong

    1998-06-01

    It is about communication grounding facility, which is made up twelve chapters. It includes general grounding with purpose, materials thermal insulating material, construction of grounding, super strength grounding method, grounding facility with grounding way and building of insulating, switched grounding with No. 1A and LCR, grounding facility of transmission line, wireless facility grounding, grounding facility in wireless base station, grounding of power facility, grounding low-tenton interior power wire, communication facility of railroad, install of arrester in apartment and house, install of arrester on introduction and earth conductivity and measurement with introduction and grounding resistance.

  4. Accelerator School Success

    CERN Multimedia

    2004-01-01

    Accelerator specialists don't grow on trees: training them is the job of the CERN Accelerator School (CAS). Group photo during visit to the Daresbury Laboratory. CAS and the CCLRC Daresbury Laboratory jointly organised a specialised school on Power Converters in Warrington, England from 12-18 May 2004. The last CAS Power Converter course was in 1990, so there was plenty of ground to cover. The challenging programme proposed a review of the state of the art and the latest developments in the field, including 30 hours of tuition. The school also included a visit to the CCLRC Daresbury laboratory, a one-day excursion to Liverpool and Chester and a themed (Welsh medieval) dinner at the school's closure. A record attendance of 91 students of more than 20 different nationalities included not only participants from Europe and North America but also from Armenia, Taiwan, India, Turkey, Iran and for the first time, fee-paying students from China and Australia. European industry showed a welcome and solid interest in...

  5. Psicoterapia de grupo de apoio multifamiliar (PGA em hospital-dia (HD psiquiátrico Multifamily support group psychotherapy for relatives (SGR in a psychiatric day hospital program (DH

    Directory of Open Access Journals (Sweden)

    José Onildo B. Contel

    1999-12-01

    Full Text Available INTRODUÇÃO: O familiar é a ponte, entre o ambiente da casa do paciente e o ambiente terapêutico do hospital-dia (HD, onde o paciente permanece das 7h30 às 15h30, de segunda a sexta-feira. A complexidade para a integração do exercício dessa tarefa e suas conseqüências para o tratamento em HD, levou-nos a criar a Psicoterapia de Grupo de Apoio multifamiliar (PGA para facilitar o exame das vissicitudes desta via de duas mãos entre a residência e o HD. OBJETIVOS: As características, liderança e fatores terapêuticos de Yalom nessa PGA serão objetos do presente trabalho MÉTODO: A PGA é um grupo aberto com 1 h e 15 minutos de duração, de freqüência semanal e com coordenação, em coterapia, de um psicoterapeuta de grupo e de uma enfermeira psiquiátrica. RESULTADOS E DISCUSSÃO: Os resultados foram obtidos pelo exame de 20 grupos sucessivos, tanto após cada sessão, pelos coterapeutas e observador mudo, durante 20-30 min, como pela análise de conteúdo de 20 sessões transcritas. A presença sempre foi maior que 80% dos familiares esperados, com predomínio de mulheres, especialmente mães de pacientes. A estrutura oferecida pela liderança apressou a obtenção de resultados no curto prazo, entre 4 a 6 sessões. A Coesão Grupal de Yalom apareceu em situações comuns e criou um senso de união entre todos. CONCLUSÃO: A adesão de familiares à PGA facilita e abrevia a terapia em HD. Questiona-se quanto, no futuro, a família orientada assumirá na condução do tratamento dos seus pacientes.INTRODUCTION: The relative is the bridge between the patient's home environment and the therapeutic environment of the day-hospital (DH. The difficulties for the relative to play this task gave birth to the multi-family support group therapy (SGR. To describe the features, leadership and Yalom's therapeutic factors in the SGR is the aim of this paper. METHOD: The SGR is an open group that last for one hour and 15 minutes, meets once weekly

  6. Sector ring accelerator ''RESATRON''

    International Nuclear Information System (INIS)

    Schwabe, E.

    1980-01-01

    Project of sector ring accelerator RESATRON is described. The curiosity of this accelerator is the second cycle of acceleration of the beam after stripping it on the foil. In such an accelerator heavy ions with a different ratio Z to A can be accelerated. (S.B.)

  7. 'Grounded' Politics

    DEFF Research Database (Denmark)

    Schmidt, Garbi

    2012-01-01

    play within one particular neighbourhood: Nørrebro in the Danish capital, Copenhagen. The article introduces the concept of grounded politics to analyse how groups of Muslim immigrants in Nørrebro use the space, relationships and history of the neighbourhood for identity political statements....... The article further describes how national political debates over the Muslim presence in Denmark affect identity political manifestations within Nørrebro. By using Duncan Bell’s concept of mythscape (Bell, 2003), the article shows how some political actors idealize Nørrebro’s past to contest the present...... ethnic and religious diversity of the neighbourhood and, further, to frame what they see as the deterioration of genuine Danish identity....

  8. Compensation for incoherent ground motion

    International Nuclear Information System (INIS)

    Shigeru, Takeda; Hiroshi, Matsumoto; Masakazu, Yoshioka; Yasunori, Takeuchi; Kikuo, Kudo; Tsuneya, Tsubokawa; Mitsuaki, Nozaki; Kiyotomo, Kawagoe

    1999-01-01

    The power spectrum density and coherence function for ground motions are studied for the construction of the next generation electron-positron linear collider. It should provide a center of mass energy between 500 GeV-1 TeV with luminosity as high as 10 33 to 10 34 cm -2 sec -1 . Since the linear collider has a relatively slow repetition rate, large number of particles and small sizes of the beam should be generated and preserved in the machine to obtain the required high luminosity. One of the most critical parameters is the extremely small vertical beam size at the interaction point, thus a proper alignment system for the focusing and accelerating elements of the machine is necessary to achieve the luminosity. We describe recent observed incoherent ground motions and an alignment system to compensate the distortion by the ground motions. (authors)

  9. Multiperiodic accelerator structures for linear particle accelerators

    International Nuclear Information System (INIS)

    Tran, D.T.

    1975-01-01

    High efficiency linear accelerator structures, comprised of a succession of cylindrical resonant cavities for acceleration, are described. Coupling annular cavities are located at the periphery, each being coupled to two adjacent cylindrical cavities. (auth)

  10. Accelerators of atomic particles

    International Nuclear Information System (INIS)

    Sarancev, V.

    1975-01-01

    A brief survey is presented of accelerators and methods of accelerating elementary particles. The principle of collective accelerating of elementary particles is clarified and the problems are discussed of its realization. (B.S.)

  11. Formation keeping of unmanned ground vehicles

    Directory of Open Access Journals (Sweden)

    Muangmin Kamonwan

    2017-01-01

    Full Text Available Controlling motions of an unmanned ground vehicle becomes more popular in real world practices. Its application is useful for household chores, military services, medical purposes, and industrial revolutions, etc. An analysis of motions by using the Fundamental Equations of Constrained Motion (FECM is one effective tool to determine the motions. Its conceptualization is done in three-step procedure as follows: (I Determining an unconstrained motion (II Assigning constraint equations and (III Computing a constrained motion. The equations of motion obtained are expressed as liner functions of acceleration. Then other kinematical information of the unmanned ground vehicles can be obtained by integration its acceleration. In this work, the FECM is used as a tool to analyze motions of a group of unmanned ground vehicles in various forms. The simulation results show that control forces obtained from the approach can regulate motions of unmanned ground vehicles to maneuver in desired formations.

  12. Shielding and grounding in large detectors

    International Nuclear Information System (INIS)

    Radeka, V.

    1998-09-01

    Prevention of electromagnetic interference (EMI), or ''noise pickup,'' is an important design aspect in large detectors in accelerator environments. Shielding effectiveness as a function of shield thickness and conductivity vs the type and frequency of the interference field is described. Noise induced in transmission lines by ground loop driven currents in the shield is evaluated and the importance of low shield resistance is emphasized. Some measures for prevention of ground loops and isolation of detector-readout systems are discussed

  13. Block ground interaction of rockfalls

    Science.gov (United States)

    Volkwein, Axel; Gerber, Werner; Kummer, Peter

    2016-04-01

    During a rockfall the interaction of the falling block with the ground is one of the most important factors that define the evolution of a rockfall trajectory. It steers the rebound, the rotational movement, possibly brake effects, friction losses and damping effects. Therefore, if most reliable rockfall /trajectory simulation software is sought a good understanding of the block ground interaction is necessary. Today's rockfall codes enable the simulation of a fully 3D modelled block within a full 3D surface . However, the details during the contact, i.e. the contact duration, the penetration depth or the dimension of the marks in the ground are usually not part of the simulation. Recent field tests with rocks between 20 and 80 kg have been conducted on a grassy slope in 2014 [1]. A special rockfall sensor [2] within the blocks measured the rotational velocity and the acting accelerations during the tests. External video records and a so-called LocalPositioningSystem deliver information on the travel velocity. With these data not only the flight phases of the trajectories but also the contacts with the ground can be analysed. During the single jumps of a block the flight time, jump length, the velocity, and the rotation are known. During the single impacts their duration and the acting accelerations are visible. Further, the changes of rotational and translational velocity influence the next jump of the block. The change of the rotational velocity over the whole trajectory nicely visualizes the different phases of a rockfall regarding general acceleration and deceleration in respect to the inclination and the topography of the field. References: [1] Volkwein A, Krummenacher B, Gerber W, Lardon J, Gees F, Brügger L, Ott T (2015) Repeated controlled rockfall trajectory testing. [Abstract] Geophys. Res. Abstr. 17: EGU2015-9779. [2] Volkwein A, Klette J (2014) Semi-Automatic Determination of Rockfall Trajectories. Sensors 14: 18187-18210.

  14. Accelerators of future generation

    International Nuclear Information System (INIS)

    Kolomenskij, A.A.

    1983-01-01

    A brief review of the prospects of development of various of types accelerator over next 10 to 15 years is given. The following directions are considered: superhign energy proton accelerators and storage rings, electron-positron colliding beams, heavy ion accelerators, medium energy, high-current proton accelerators superhigh power particle beams (electrons light- and heavy ions) for inertial fusion

  15. Future accelerator technology

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1986-05-01

    A general discussion is presented of the acceleration of particles. Upon this foundation is built a categorization scheme into which all accelerators can be placed. Special attention is devoted to accelerators which employ a wake-field mechanism and a restricting theorem is examined. It is shown how the theorem may be circumvented. Comments are made on various acceleration schemes

  16. Joint kinematics and kinetics of overground accelerated running versus running on an accelerated treadmill.

    Science.gov (United States)

    Caekenberghe, Ine Van; Segers, Veerle; Aerts, Peter; Willems, Patrick; De Clercq, Dirk

    2013-07-06

    Literature shows that running on an accelerated motorized treadmill is mechanically different from accelerated running overground. Overground, the subject has to enlarge the net anterior-posterior force impulse proportional to acceleration in order to overcome linear whole body inertia, whereas on a treadmill, this force impulse remains zero, regardless of belt acceleration. Therefore, it can be expected that changes in kinematics and joint kinetics of the human body also are proportional to acceleration overground, whereas no changes according to belt acceleration are expected on a treadmill. This study documents kinematics and joint kinetics of accelerated running overground and running on an accelerated motorized treadmill belt for 10 young healthy subjects. When accelerating overground, ground reaction forces are characterized by less braking and more propulsion, generating a more forward-oriented ground reaction force vector and a more forwardly inclined body compared with steady-state running. This change in body orientation as such is partly responsible for the changed force direction. Besides this, more pronounced hip and knee flexion at initial contact, a larger hip extension velocity, smaller knee flexion velocity and smaller initial plantarflexion velocity are associated with less braking. A larger knee extension and plantarflexion velocity result in larger propulsion. Altogether, during stance, joint moments are not significantly influenced by acceleration overground. Therefore, we suggest that the overall behaviour of the musculoskeletal system (in terms of kinematics and joint moments) during acceleration at a certain speed remains essentially identical to steady-state running at the same speed, yet acting in a different orientation. However, because acceleration implies extra mechanical work to increase the running speed, muscular effort done (in terms of power output) must be larger. This is confirmed by larger joint power generation at the level of

  17. Joint kinematics and kinetics of overground accelerated running versus running on an accelerated treadmill

    Science.gov (United States)

    Van Caekenberghe, Ine; Segers, Veerle; Aerts, Peter; Willems, Patrick; De Clercq, Dirk

    2013-01-01

    Literature shows that running on an accelerated motorized treadmill is mechanically different from accelerated running overground. Overground, the subject has to enlarge the net anterior–posterior force impulse proportional to acceleration in order to overcome linear whole body inertia, whereas on a treadmill, this force impulse remains zero, regardless of belt acceleration. Therefore, it can be expected that changes in kinematics and joint kinetics of the human body also are proportional to acceleration overground, whereas no changes according to belt acceleration are expected on a treadmill. This study documents kinematics and joint kinetics of accelerated running overground and running on an accelerated motorized treadmill belt for 10 young healthy subjects. When accelerating overground, ground reaction forces are characterized by less braking and more propulsion, generating a more forward-oriented ground reaction force vector and a more forwardly inclined body compared with steady-state running. This change in body orientation as such is partly responsible for the changed force direction. Besides this, more pronounced hip and knee flexion at initial contact, a larger hip extension velocity, smaller knee flexion velocity and smaller initial plantarflexion velocity are associated with less braking. A larger knee extension and plantarflexion velocity result in larger propulsion. Altogether, during stance, joint moments are not significantly influenced by acceleration overground. Therefore, we suggest that the overall behaviour of the musculoskeletal system (in terms of kinematics and joint moments) during acceleration at a certain speed remains essentially identical to steady-state running at the same speed, yet acting in a different orientation. However, because acceleration implies extra mechanical work to increase the running speed, muscular effort done (in terms of power output) must be larger. This is confirmed by larger joint power generation at the level

  18. Tractor accelerated test on test rig

    Directory of Open Access Journals (Sweden)

    M. Mattetti

    2013-09-01

    Full Text Available The experimental tests performed to validate a tractor prototype before its production, need a substantial financial and time commitment. The tests could be reduced using accelerated tests able to reproduce on the structural part of the tractor, the same damage produced on the tractor during real life in a reduced time. These tests were usually performed reproducing a particular harsh condition a defined number of times, as for example using a bumpy road on track to carry out the test in any weather condition. Using these procedures the loads applied on the tractor structure are different with respect to those obtained during the real use, with the risk to apply loads hard to find in reality. Recently it has been demonstrated how, using the methodologies designed for cars, it is possible to also expedite the structural tests for tractors. In particular, automotive proving grounds were recently successfully used with tractors to perform accelerated structural tests able to reproduce the real use of the machine with an acceleration factor higher than that obtained with the traditional methods. However, the acceleration factor obtained with a tractor on proving grounds is in any case reduced due to the reduced speed of the tractors with respect to cars. In this context, the goal of the paper is to show the development of a methodology to perform an accelerated structural test on a medium power tractor using a 4 post test rig. In particular, several proving ground testing conditions have been performed to measure the loads on the tractor. The loads obtained were then edited to remove the not damaging portion of signals, and finally the loads obtained were reproduced in a 4 post test rig. The methodology proposed could be a valid alternative to the use of a proving ground to reproduce accelerated structural tests on tractors.

  19. 14 CFR 25.109 - Accelerate-stop distance.

    Science.gov (United States)

    2010-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Performance § 25.109 Accelerate-stop distance. (a...) The maximum tire-to-ground wet runway braking coefficient of friction is defined as: ER18FE98.004 Where— Tire Pressure=maximum airplane operating tire pressure (psi); μt/gMAX=maximum tire-to-ground...

  20. Analysis of bias voltage dependent spectral response in Ga0.51In0.49P/Ga0.99In0.01As/Ge triple junction solar cell

    International Nuclear Information System (INIS)

    Sogabe, Tomah; Ogura, Akio; Okada, Yoshitaka

    2014-01-01

    Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR −V bias ) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR −V bias for Ga 0.51 In 0.49 P/Ga 0.99 In 0.01 As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR −V bias measurements. The profile of SR−V bias curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell

  1. 2014 CERN Accelerator Schools: Plasma Wake Acceleration

    CERN Multimedia

    2014-01-01

    A specialised school on Plasma Wake Acceleration will be held at CERN, Switzerland from 23-29 November, 2014.   This course will be of interest to staff and students in accelerator laboratories, university departments and companies working in or having an interest in the field of new acceleration techniques. Following introductory lectures on plasma and laser physics, the course will cover the different components of a plasma wake accelerator and plasma beam systems. An overview of the experimental studies, diagnostic tools and state of the art wake acceleration facilities, both present and planned, will complement the theoretical part. Topical seminars and a visit of CERN will complete the programme. Further information can be found at: http://cas.web.cern.ch/cas/PlasmaWake2014/CERN-advert.html http://indico.cern.ch/event/285444/

  2. Ground water '89

    International Nuclear Information System (INIS)

    1989-01-01

    The proceedings of the 5th biennial symposium of the Ground Water Division of the Geological Society of South Africa are presented. The theme of the symposium was ground water and mining. Papers were presented on the following topics: ground water resources; ground water contamination; chemical analyses of ground water and mining and its influece on ground water. Separate abstracts were prepared for 5 of the papers presented. The remaining papers were considered outside the subject scope of INIS

  3. Dynamic tire pressure sensor for measuring ground vibration.

    Science.gov (United States)

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L

    2012-11-07

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application.

  4. Other people's accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-06-15

    The first report from the Washington Accelerator Conference concentrated on news from the particle physics centres. But the bulk of the Conference covered the use of accelerators in other fields, underlining this valuable spinoff from particle physics.

  5. Improved plasma accelerator

    Science.gov (United States)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  6. The electron accelerator Ridgetron

    International Nuclear Information System (INIS)

    Hayashizaki, N.; Hattori, T.; Odera, M.; Fujisawa, T.

    1999-01-01

    Many electron accelerators of DC or RF type have been widely used for electron beam irradiation (curing, crosslinking of polymers, sterilization of medical disposables, preservation of food, etc.). Regardless of the acceleration energy, the accelerators to be installed in industrial facilities, have to satisfy the requires of compact size, low power consumption and stable operation. The DC accelerator is realized very compact in the energy under 300 keV, however, it is large to prevent the discharge of an acceleration column in the energy over 300 keV. The RF electron accelerator Ridgetron has been developed to accelerate the continuous beam of the 0.5-10 MeV range in compact space. It is the first example as an electron accelerator incorporated a ridged RF cavity. A prototype system of final energy of 2.5 MeV has been studied to confirm the feasibility at present

  7. High brightness electron accelerator

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of accelerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity. 5 figs

  8. Unified accelerator libraries

    International Nuclear Information System (INIS)

    Malitsky, Nikolay; Talman, Richard

    1997-01-01

    A 'Universal Accelerator Libraries' (UAL) environment is described. Its purpose is to facilitate program modularity and inter-program and inter-process communication among heterogeneous programs. The goal ultimately is to facilitate model-based control of accelerators

  9. YEREVAN: Acceleration workshop

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Sponsored by the Yerevan Physics Institute in Armenia, a Workshop on New Methods of Charged Particle Acceleration in October near the Nor Amberd Cosmic Ray Station attracted participants from most major accelerator centres in the USSR and further afield

  10. San Francisco Accelerator Conference

    International Nuclear Information System (INIS)

    Southworth, Brian

    1991-01-01

    'Where are today's challenges in accelerator physics?' was the theme of the open session at the San Francisco meeting, the largest ever gathering of accelerator physicists and engineers

  11. Large tandem accelerators

    International Nuclear Information System (INIS)

    Jones, C.M.

    1976-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of tandem accelerators designed to operate at maximum terminal potentials in the range 14 to 30 MV. In addition, a number of older tandem accelerators are now being significantly upgraded to improve their heavy ion performance. Both of these developments have reemphasized the importance of negative heavy ion sources. The new large tandem accelerators are described, and the requirements placed on negative heavy ion source technology by these and other tandem accelerators used for the acceleration of heavy ions are discussed. First, a brief description is given of the large tandem accelerators which have been completed recently, are under construction, or are funded for construction, second, the motivation for construction of these accelerators is discussed, and last, criteria for negative ion sources for use with these accelerators are presented

  12. Vp x B acceleration

    International Nuclear Information System (INIS)

    Sugihara, Ryo.

    1987-05-01

    A unique particle acceleration by an electrostatic (ES) wave, a magnetosonic shock wave as well as an electromagnetic (EM) wave is reviewed. The principle of the acceleration is that when a charged particle is carried across an external magnetic field the charge feels a DC field (the Lorentz force) and is accelerated. The theory for the ES wave acceleration is experimentally verified thought it is semi-quantitative. The shock acceleration is extensively studied theoretically and in a particle simulation method and the application is extended to phenomena in interplanetary space. The EM wave acceleration is based on a trapping in a moving neutral sheet created by the wave magnetic field and the external magnetic field, and the particle can be accelerated indefinitely. A brief sketch on a slow-wave-structure for this acceleration will be given. (author)

  13. Accelerator-timing system

    International Nuclear Information System (INIS)

    Timmer, E.; Heine, E.

    1985-01-01

    Along the NIKHEF accelerator in Amsterdam (Netherlands), at several places a signal is needed for the sychronisation of all devices with the acceleration process. In this report, basic principles and arrangements of this timing system are described

  14. Linear accelerator: A concept

    Science.gov (United States)

    Mutzberg, J.

    1972-01-01

    Design is proposed for inexpensive accelerometer which would work by applying pressure to fluid during acceleration. Pressure is used to move shuttle, and shuttle movement is sensed and calibrated to give acceleration readings.

  15. Heavy ion accelerators

    International Nuclear Information System (INIS)

    Schmelzer, C.

    1974-01-01

    This review of the present state of work on heavy-ion accelerators pays particular attention to the requirements for nuclear research. It is divided into the following sections: single-particle versus collective acceleration, heavy-ion accelerators, beam quality, and a status report on the UNILAC facility. Among the topics considered are the recycling cyclotron, linacs with superconducting resonators, and acceleration to the GeV/nucleon range. (8 figures, 2 tables) (U.S.)

  16. Accelerators at school

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Latest subject covered by the CERN Accelerator School was 'Applied Geodesy of Particle Accelerators', which attracted an impressive number of outside participants to CERN for a week in April. Since the forerunners of today's particle accelerators were demonstrated over 50 years ago, the positioning of accelerator components has progressed from the laboratory bench-top to tunnels tens of kilometres long. Despite this phenomenal growth in size, sub-millimetre accuracy is still required

  17. Accelerators at school

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-06-15

    Latest subject covered by the CERN Accelerator School was 'Applied Geodesy of Particle Accelerators', which attracted an impressive number of outside participants to CERN for a week in April. Since the forerunners of today's particle accelerators were demonstrated over 50 years ago, the positioning of accelerator components has progressed from the laboratory bench-top to tunnels tens of kilometres long. Despite this phenomenal growth in size, sub-millimetre accuracy is still required.

  18. Accelerators for Medicine

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    This lecture will review the different applications of particle accelerators to the medical field, from cancer treatment with beams of accelerator-produced particles (photons, electrons, protons, ions and neutrons) to the generation of radioactive isotopes used in medical diagnostics, in cancer therapy and in the new domain of theragnostics. For each application will be outlined the state of the art, the potential, and the accelerator challenges to be faced to meet the increasing demand for therapeutic procedures based on accelerators.

  19. Large electrostatic accelerators

    International Nuclear Information System (INIS)

    Jones, C.M.

    1984-01-01

    The paper is divided into four parts: a discussion of the motivation for the construction of large electrostatic accelerators, a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year

  20. Particle beam accelerator

    International Nuclear Information System (INIS)

    Turner, N.L.

    1982-01-01

    A particle beam accelerator is described which has several electrodes that are selectively short circuited together synchronously with changes in the magnitude of a DC voltage applied to the accelerator. By this method a substantially constant voltage gradient is maintained along the length of the unshortened electrodes despite variations in the energy applied to the beam by the accelerator. The invention has particular application to accelerating ion beams that are implanted into semiconductor wafers. (U.K.)

  1. Superconducting accelerator technology

    International Nuclear Information System (INIS)

    Grunder, H.A.; Hartline, B.K.

    1986-01-01

    Modern and future accelerators for high energy and nuclear physics rely increasingly on superconducting components to achieve the required magnetic fields and accelerating fields. This paper presents a practical overview of the phenomenon of superconductivity, and describes the design issues and solutions associated with superconducting magnets and superconducting rf acceleration structures. Further development and application of superconducting components promises increased accelerator performance at reduced electric power cost

  2. Applications of particle accelerators

    International Nuclear Information System (INIS)

    Barbalat, O.

    1994-01-01

    Particle accelerators are now widely used in a variety of applications for scientific research, applied physics, medicine, industrial processing, while possible utilisation in power engineering is envisaged. Earlier presentations of this subject, given at previous CERN Accelerator School sessions have been updated with papers contributed to the first European Conference on Accelerators in Applied Research and Technology (ECAART) held in September 1989 in Frankfurt and to the Second European Particle Accelerator Conference in Nice in June 1990. (orig.)

  3. Impact Accelerations of Barefoot and Shod Running.

    Science.gov (United States)

    Thompson, M; Seegmiller, J; McGowan, C P

    2016-05-01

    During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related overuse injuries. Additionally, the fore/mid foot strike pattern that is adopted by most individuals when running barefoot may reduce impact force transmission. The aim of the present study was to compare the effects of the barefoot running form (fore/mid foot strike & decreased stride length) and running shoes on running kinetics and impact accelerations. 10 healthy, physically active, heel strike runners ran in 3 conditions: shod, barefoot and barefoot while heel striking, during which 3-dimensional motion analysis, ground reaction force and accelerometer data were collected. Shod running was associated with increased ground reaction force and impact peak magnitudes, but decreased impact accelerations, suggesting that the midsole of running shoes helps to attenuate impact forces. Barefoot running exhibited a similar decrease in impact accelerations, as well as decreased impact peak magnitude, which appears to be due to a decrease in stride length and/or a more plantarflexed position at ground contact. © Georg Thieme Verlag KG Stuttgart · New York.

  4. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

    Introduction to accelerator physics The CERN Accelerator School: Introduction to Accelerator Physics, which should have taken place in Istanbul, Turkey, later this year has now been relocated to Budapest, Hungary.  Further details regarding the new hotel and dates will be made available as soon as possible on a new Indico site at the end of May.

  5. Angular Acceleration without Torque?

    Science.gov (United States)

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  6. Accelerators and Dinosaurs

    CERN Multimedia

    Turner, Michael Stanley

    2003-01-01

    Using naturally occuring particles on which to research might have made accelerators become extinct. But in fact, results from astrophysics have made accelerator physics even more important. Not only are accelerators used in hospitals but they are also being used to understand nature's inner workings by searching for Higgs bosons, CP violation, neutrino mass and dark matter (2 pages)

  7. Far field acceleration

    International Nuclear Information System (INIS)

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail

  8. Virtual Accelerator for Accelerator Optics Improvement

    CERN Document Server

    Yan Yi Ton; Decker, Franz Josef; Ecklund, Stanley; Irwin, John; Seeman, John; Sullivan, Michael K; Turner, J L; Wienands, Ulrich

    2005-01-01

    Through determination of all quadrupole strengths and sextupole feed-downs by fitting quantities derivable from precision orbit measurement, one can establish a virtual accelerator that matches the real accelerator optics. These quantities (the phase advances, the Green's functions, and the coupling eigen-plane ellipses tilt angles and axis ratios) are obtained by analyzing turn-by-turn Beam Position Monitor (BPM) data with a model-independent analysis (MIA). Instead of trying to identify magnet errors, a limited number of quadrupoles are chosen for optimized strength adjustment to improve the virtual accelerator optics and then applied to the real accelerator accordingly. These processes have been successfully applied to PEP-II rings for beta beating fixes, phase and working tune adjustments, and linear coupling reduction to improve PEP-II luminosity.

  9. Preinjector for Linac 1, accelerating column

    CERN Multimedia

    1974-01-01

    For a description of the Linac 1 preinjector, please see first 7403070X. High up on the wall of the Faraday cage (7403073X) is this drum-shaped container of the ion source (7403083X). It is mounted at the HV end of the accelerating column through which the ions (usually protons; many other types of ions in the course of its long history) proceed through the Faraday cage wall to the low-energy end (at ground potential) of Linac 1. The 520 kV accelerating voltage was supplied by a SAMES generator (7403074X).

  10. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  11. Notes on Laser Acceleration

    International Nuclear Information System (INIS)

    Tajima, T.

    2008-01-01

    This note intends to motivate our effort toward the advent of new methods of particle acceleration, utilizing the fast rising laser technology. By illustrating the underlying principles in an intuitive manner and thus less jargon-clad fashion, we seek a direction in which we shall be able to properly control and harness the promise of laser acceleration. First we review the idea behind the laser wakefield. We then go on to examine ion acceleration by laser. We examine the sheath acceleration in particular and look for the future direction that allows orderly acceleration of ions in high energies

  12. Ground water and energy

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    This national workshop on ground water and energy was conceived by the US Department of Energy's Office of Environmental Assessments. Generally, OEA needed to know what data are available on ground water, what information is still needed, and how DOE can best utilize what has already been learned. The workshop focussed on three areas: (1) ground water supply; (2) conflicts and barriers to ground water use; and (3) alternatives or solutions to the various issues relating to ground water. (ACR)

  13. Industrial Application of Accelerators

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    At CERN, we are very familiar with large, high energy particle accelerators. However, in the world outside CERN, there are more than 35000 accelerators which are used for applications ranging from treating cancer, through making better electronics to removing harmful micro-organisms from food and water. These are responsible for around $0.5T of commerce each year. Almost all are less than 20 MeV and most use accelerator types that are somewhat different from what is at CERN. These lectures will describe some of the most common applications, some of the newer applications in development and the accelerator technology used for them. It will also show examples of where technology developed for particle physics is now being studied for these applications. Rob Edgecock is a Professor of Accelerator Science, with a particular interest in the medical applications of accelerators. He works jointly for the STFC Rutherford Appleton Laboratory and the International Institute for Accelerator Applications at the Univer...

  14. Industrial Application of Accelerators

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    At CERN, we are very familiar with large, high energy particle accelerators. However, in the world outside CERN, there are more than 35000 accelerators which are used for applications ranging from treating cancer, through making better electronics to removing harmful micro-organisms from food and water. These are responsible for around $0.5T of commerce each year. Almost all are less than 20 MeV and most use accelerator types that are somewhat different from what is at CERN. These lectures will describe some of the most common applications, some of the newer applications in development and the accelerator technology used for them. It will also show examples of where technology developed for particle physics is now being studied for these applications. Rob Edgecock is a Professor of Accelerator Science, with a particular interest in the medical applications of accelerators. He works jointly for the STFC Rutherford Appleton Laboratory and the International Institute for Accelerator Applications at the Uni...

  15. Accelerations in Flight

    Science.gov (United States)

    Doolittle, J H

    1925-01-01

    This work on accelerometry was done at McCook Field for the purpose of continuing the work done by other investigators and obtaining the accelerations which occur when a high-speed pursuit airplane is subjected to the more common maneuvers. The accelerations obtained in suddenly pulling out of a dive with well-balanced elevators are shown to be within 3 or 4 per cent of the theoretically possible accelerations. The maximum acceleration which a pilot can withstand depends upon the length of time the acceleration is continued. It is shown that he experiences no difficulty under the instantaneous accelerations as high as 7.8 G., but when under accelerations in excess of 4.5 G., continued for several seconds, he quickly loses his faculties.

  16. Accelerators for energy

    International Nuclear Information System (INIS)

    Inoue, Makoto

    2000-01-01

    A particle accelerator is a device to consume energy but not to produce it. Then, the titled accelerator seems to mean an accelerator for using devices related to nuclear energy. For an accelerator combined to nuclear fissionable fuel, neutron sources are D-T type, (gamma, n) reaction using electron beam type spallation type, and so forth. At viewpoints of powers of incident beam and formed neutron, a spallation type source using high energy proton is told to be effective but others have some advantages by investigation on easy operability, easy construction, combustion with target, energy and directivity of neutron, and so forth. Here were discussed on an accelerator for research on accelerator driven energy system by dividing its researching steps, and on kind, energy, beam intensity, and so forth of an accelerator suitable for it. And, space electric charge effect at beam propagation direction controlled by beam intensity of cyclotron was also commented. (G.K.)

  17. Seismic design technology for breeder reactor structures. Volume 1. Special topics in earthquake ground motion

    International Nuclear Information System (INIS)

    Reddy, D.P.

    1983-04-01

    This report is divided into twelve chapters: seismic hazard analysis procedures, statistical and probabilistic considerations, vertical ground motion characteristics, vertical ground response spectrum shapes, effects of inclined rock strata on site response, correlation of ground response spectra with intensity, intensity attenuation relationships, peak ground acceleration in the very mean field, statistical analysis of response spectral amplitudes, contributions of body and surface waves, evaluation of ground motion characteristics, and design earthquake motions

  18. Development of bipolar-pulse accelerator for intense pulsed ion beam acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Masugata, Katsumi [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: masugata@eng.toyama-u.ac.jp; Shimizu, Yuichro [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan); Fujioka, Yuhki [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan); Kitamura, Iwao [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan); Tanoue, Hisao [National Institute of Advanced Industry Science and Technology, 1-1-1, Umezono, Tsukuba-shi, Ibaraki 305-8568 (Japan); Arai, Kazuo [National Institute of Advanced Industry Science and Technology, 1-1-1, Umezono, Tsukuba-shi, Ibaraki 305-8568 (Japan)

    2004-12-21

    To improve the purity of intense pulsed ion beams, a new type of pulsed ion beam accelerator named 'bipolar pulse accelerator' was proposed. To confirm the principle of the accelerator a prototype of the experimental system was developed. The system utilizes By type magnetically insulated acceleration gap and operated with single polar negative pulse. A coaxial gas puff plasma gun was used as an ion source, which was placed inside the grounded anode. Source plasma (nitrogen) of current density {approx}25A/cm2, duration {approx}1.5{mu}s was injected into the acceleration gap by the plasma gun. The ions were successfully accelerated from the grounded anode to the drift tube by applying negative pulse of voltage 240kV, duration 100ns to the drift tube. Pulsed ion beam of current density {approx}40A/cm2, duration {approx}50ns was obtained at 41mm downstream from the anode surface. To evaluate the irradiation effect of the ion beam to solid material, an amorphous silicon thin film of thickness {approx}500nm was used as the target, which was deposited on the glass substrate. The film was found to be poly-crystallized after 4-shots of the pulsed nitrogen ion beam irradiation.

  19. Particle-accelerator decommissioning

    International Nuclear Information System (INIS)

    Opelka, J.H.; Mundis, R.L.; Marmer, G.J.; Peterson, J.M.; Siskind, B.; Kikta, M.J.

    1979-12-01

    Generic considerations involved in decommissioning particle accelerators are examined. There are presently several hundred accelerators operating in the United States that can produce material containing nonnegligible residual radioactivity. Residual radioactivity after final shutdown is generally short-lived induced activity and is localized in hot spots around the beam line. The decommissioning options addressed are mothballing, entombment, dismantlement with interim storage, and dismantlement with disposal. The recycle of components or entire accelerators following dismantlement is a definite possibility and has occurred in the past. Accelerator components can be recycled either immediately at accelerator shutdown or following a period of storage, depending on the nature of induced activation. Considerations of cost, radioactive waste, and radiological health are presented for four prototypic accelerators. Prototypes considered range from small accelerators having minimal amounts of radioactive mmaterial to a very large accelerator having massive components containing nonnegligible amounts of induced activation. Archival information on past decommissionings is presented, and recommendations concerning regulations and accelerator design that will aid in the decommissioning of an accelerator are given

  20. An introduction to acceleration mechanisms

    International Nuclear Information System (INIS)

    Palmer, R.B.

    1987-05-01

    This paper discusses the acceleration of charged particles by electromagnetic fields, i.e., by fields that are produced by the motion of other charged particles driven by some power source. The mechanisms that are discussed include: Ponderamotive Forces, Acceleration, Plasma Beat Wave Acceleration, Inverse Free Electron Laser Acceleration, Inverse Cerenkov Acceleration, Gravity Acceleration, 2D Linac Acceleration and Conventional Iris Loaded Linac Structure Acceleration

  1. Accelerator and radiation physics

    CERN Document Server

    Basu, Samita; Nandy, Maitreyee

    2013-01-01

    "Accelerator and radiation physics" encompasses radiation shielding design and strategies for hadron therapy accelerators, neutron facilities and laser based accelerators. A fascinating article describes detailed transport theory and its application to radiation transport. Detailed information on planning and design of a very high energy proton accelerator can be obtained from the article on radiological safety of J-PARC. Besides safety for proton accelerators, the book provides information on radiological safety issues for electron synchrotron and prevention and preparedness for radiological emergencies. Different methods for neutron dosimetry including LET based monitoring, time of flight spectrometry, track detectors are documented alongwith newly measured experimental data on radiation interaction with dyes, polymers, bones and other materials. Design of deuteron accelerator, shielding in beam line hutches in synchrotron and 14 MeV neutron generator, various radiation detection methods, their characteriza...

  2. 2014 Accelerators meeting, Grenoble

    International Nuclear Information System (INIS)

    Lucotte, Arnaud; Lamy, Thierry; De Conto, Jean-Marie; Fontaine, Alain; Revol, Jean-Luc; Nadolski, Laurent S.; Kazamias, Sophie; Vretenar, Maurizio; Ferrando, Philippe; Laune, Bernard; Vedrine, Pierre

    2014-10-01

    The Accelerators meeting is organised every two years by the Accelerators division of the French Society of Physics (SFP). It brings together about 50 participants during a one-day meeting. The morning sessions are devoted to scientific presentations while the afternoon is dedicated to technical visits of facilities. This document brings together the available presentations (slides): 1 - Presentation of the Laboratory of subatomic physics and cosmology - LPSC-Grenoble (Lucotte, Arnaud; Lamy, Thierry); 2 - Presentation of the Accelerators division of the French Society of Physics (Fontaine, Alain; Revol, Jean-Luc); 3 - Presentation of Grenoble's master diplomas in Accelerator physics (Nadolski, Laurent S.); 4 - Presentation of Paris' master diplomas in big instruments (Kazamias, Sophie); 5 - Particle accelerators and European Union's projects (Vretenar, Maurizio); 6 - French research infrastructures (Ferrando, Philippe); 7 - Coordination of accelerators activity in France (Laune, Bernard; Vedrine, Pierre)

  3. Accelerator reliability workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, L; Duru, Ph; Koch, J M; Revol, J L; Van Vaerenbergh, P; Volpe, A M; Clugnet, K; Dely, A; Goodhew, D

    2002-07-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop.

  4. Accelerator reliability workshop

    International Nuclear Information System (INIS)

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D.

    2002-01-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop

  5. Acceleration of radioactive ions

    International Nuclear Information System (INIS)

    Laxdal, R.E.

    2003-01-01

    There is an intense interest world-wide in the use of radioactive ion beams (RIBs) for experiment. In many existing or proposed facilities ions are produced or collected at source potential, ionized and re-accelerated. Within the past year three new ISOL based facilities have added dedicated post-accelerators to deliver accelerated RIBs to experiment. The paper gives an overview of RIB accelerators present and future, and explores the inherent features in the various acceleration methods with an emphasis on heavy ion linacs. The ISAC-I and ISAC-II post-accelerators are discussed as examples. Commissioning results and initial operating experience with ISAC-I will be presented

  6. Nuclear physics accelerator facilities

    International Nuclear Information System (INIS)

    1988-12-01

    This paper describes many of the nuclear physics heavy-ion accelerator facilities in the US and the research programs being conducted. The accelerators described are: Argonne National Laboratory--ATLAS; Brookhaven National Laboratory--Tandem/AGS Heavy Ion Facility; Brookhaven National Laboratory--Relativistic Heavy Ion Collider (RHIC) (Proposed); Continuous Electron Beam Accelerator Facility; Lawrence Berkeley Laboratory--Bevalac; Lawrence Berkeley Laboratory--88-Inch Cyclotron; Los Alamos National Laboratory--Clinton P. Anderson Meson Physics Facility (LAMPF); Massachusetts Institute of Technology--Bates Linear Accelerator Center; Oak Ridge National Laboratory--Holifield Heavy Ion Research Facility; Oak Ridge National Laboratory--Oak Ridge Electron Linear Accelerator; Stanford Linear Accelerator Center--Nuclear Physics Injector; Texas AandM University--Texas AandM Cyclotron; Triangle Universities Nuclear Laboratory (TUNL); University of Washington--Tandem/Superconducting Booster; and Yale University--Tandem Van de Graaff

  7. Japan Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    At the international level, the high energy accelerator scene evolves rapidly and the International Conference on High Energy Accelerators is where its strong pulse can best be felt. This year, the Conference was held for the first time in Japan, with the 14th meeting in the series having been hosted in August by the Japanese KEK National Laboratory for High Energy Physics, Tsukuba. The venue was a recognition of the premier accelerator physics and technology status achieved by this diligent nation

  8. Accelerator shielding benchmark problems

    International Nuclear Information System (INIS)

    Hirayama, H.; Ban, S.; Nakamura, T.

    1993-01-01

    Accelerator shielding benchmark problems prepared by Working Group of Accelerator Shielding in the Research Committee on Radiation Behavior in the Atomic Energy Society of Japan were compiled by Radiation Safety Control Center of National Laboratory for High Energy Physics. Twenty-five accelerator shielding benchmark problems are presented for evaluating the calculational algorithm, the accuracy of computer codes and the nuclear data used in codes. (author)

  9. Plasma particle accelerators

    International Nuclear Information System (INIS)

    Dawson, J.M.

    1988-01-01

    The Superconducting Supercollider (SSC) will require an 87-kilometer accelerator ring to boost particles to 40 TeV. The SSC's size is due in part to the fact that its operating principle is the same one that has dominated accelerator design for 50 years: it guides particles by means of magnetic fields and propels them by strong electric fields. If one were to build an equally powerful but smaller accelerator, one would need to increase the strength of the guiding and propelling fields. Actually, however, conventional technology may not be able to provide significant increases in field strength. There are two reasons. First, the forces from magnetic fields are becoming greater than the structural forces that hold a magnetic material together; the magnets that produce these fields would themselves be torn apart. Second, the energy from electric fields is reaching the energies that bind electrons to atoms; it would tear electrons from nuclei in the accelerator's support structures. It is the electric field problem that plasma accelerators can overcome. Plasma particle accelerators are based on the principle that particles can be accelerated by the electric fields generated within a plasma. Because the plasma has already been ionized, plasma particle accelerators are not susceptible to electron dissociation. They can in theory sustain accelerating fields thousands of times stronger that conventional technologies. So far two methods for creating plasma waves for accelerators have been proposed and tested: the wakefield and the beat wave. Although promising electric fields have been produced, more research is necessary to determine whether plasma particle accelerators can compete with the existing accelerators. 7 figs

  10. Wake field accelerators

    International Nuclear Information System (INIS)

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered

  11. CONFERENCE: Computers and accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1984-01-15

    In September of last year a Conference on 'Computers in Accelerator Design and Operation' was held in West Berlin attracting some 160 specialists including many from outside Europe. It was a Europhysics Conference, organized by the Hahn-Meitner Institute with Roman Zelazny as Conference Chairman, postponed from an earlier intended venue in Warsaw. The aim was to bring together specialists in the fields of accelerator design, computer control and accelerator operation.

  12. Japan Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-11-15

    At the international level, the high energy accelerator scene evolves rapidly and the International Conference on High Energy Accelerators is where its strong pulse can best be felt. This year, the Conference was held for the first time in Japan, with the 14th meeting in the series having been hosted in August by the Japanese KEK National Laboratory for High Energy Physics, Tsukuba. The venue was a recognition of the premier accelerator physics and technology status achieved by this diligent nation.

  13. CERN Accelerator School

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The CERN Accelerator School (CAS) recently held its Advanced Accelerator Physics course in Greece on the island of Rhodes. Complementing the general course in Finland last year, this course was organized together with the University of Athens and NCSR. Demokritos. Accelerator specialists from Europe, CIS, Japan and USA followed two weeks of ''state-of-theart'' lectures designed to complete their education in the field

  14. Ground Motion Prediction Equations Empowered by Stress Drop Measurement

    Science.gov (United States)

    Miyake, H.; Oth, A.

    2015-12-01

    Significant variation of stress drop is a crucial issue for ground motion prediction equations and probabilistic seismic hazard assessment, since only a few ground motion prediction equations take into account stress drop. In addition to average and sigma studies of stress drop and ground motion prediction equations (e.g., Cotton et al., 2013; Baltay and Hanks, 2014), we explore 1-to-1 relationship for each earthquake between stress drop and between-event residual of a ground motion prediction equation. We used the stress drop dataset of Oth (2013) for Japanese crustal earthquakes ranging 0.1 to 100 MPa and K-NET/KiK-net ground motion dataset against for several ground motion prediction equations with volcanic front treatment. Between-event residuals for ground accelerations and velocities are generally coincident with stress drop, as investigated by seismic intensity measures of Oth et al. (2015). Moreover, we found faster attenuation of ground acceleration and velocities for large stress drop events for the similar fault distance range and focal depth. It may suggest an alternative parameterization of stress drop to control attenuation distance rate for ground motion prediction equations. We also investigate 1-to-1 relationship and sigma for regional/national-scale stress drop variation and current national-scale ground motion equations.

  15. Applying the accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Barbalat, Oscar

    1989-12-15

    Originally developed as tools for frontier physics, particle accelerators provide valuable spinoff benefits in applied research and technology. These accelerator applications are the subject of a biennial meeting in Denton, Texas, but the increasing activity in this field resulted this year (5-9 September) in the first European Conference on Accelerators in Applied Research and Technology, organized by K. Bethge of Frankfurt's Goethe University. The meeting reflected a wide range of applications - ion beam analysis, exploitation of nuclear microbeams, accelerator mass spectrometry, applications of photonuclear reactions, ion beam processing, synchrotron radiation for semiconductor technology, specialized technology.

  16. Laser-driven accelerators

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Several devices for using laser fields have been proposed and they can be classified in three broad categories - 'far-field' accelerators (such as the principle of inverse free electron lasers), 'media' accelerators (which, for example, use the inverse Cherenkov effect or laser-controlled plasma waves), and 'near-field' accelerators (using a loaded guiding structure such as cavities or gratings). These different approaches come from the fact that a particle cannot be accelerated by the absorption of single photons (because of momentum conservation) and thus some other element has to intervene. (orig./HSI).

  17. Illinois Accelerator Research Center

    Science.gov (United States)

    Kroc, Thomas K.; Cooper, Charlie A.

    The Illinois Accelerator Research Center (IARC) hosts a new accelerator development program at Fermi National Accelerator Laboratory. IARC provides access to Fermi's state-of-the-art facilities and technologies for research, development and industrialization of particle accelerator technology. In addition to facilitating access to available existing Fermi infrastructure, the IARC Campus has a dedicated 36,000 ft2 Heavy Assembly Building (HAB) with all the infrastructure needed to develop, commission and operate new accelerators. Connected to the HAB is a 47,000 ft2 Office, Technology and Engineering (OTE) building, paid for by the state, that has office, meeting, and light technical space. The OTE building, which contains the Accelerator Physics Center, and nearby Accelerator and Technical divisions provide IARC collaborators with unique access to world class expertise in a wide array of accelerator technologies. At IARC scientists and engineers from Fermilab and academia work side by side with industrial partners to develop breakthroughs in accelerator science and translate them into applications for the nation's health, wealth and security.

  18. High Gradient Accelerator Research

    International Nuclear Information System (INIS)

    Temkin, Richard

    2016-01-01

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  19. Interacting with accelerators

    International Nuclear Information System (INIS)

    Dasgupta, S.

    1994-01-01

    Accelerators are research machines which produce energetic particle beam for use as projectiles to effect nuclear reactions. These machines along with their services and facilities may occupy very large areas. The man-machine interface of accelerators has evolved with technological changes in the computer industry and may be partitioned into three phases. The present paper traces the evolution of man-machine interface from the earliest accelerators to the present computerized systems incorporated in modern accelerators. It also discusses the advantages of incorporating expert system technology for assisting operators. (author). 8 ref

  20. FFAGS for muon acceleration

    International Nuclear Information System (INIS)

    Berg, J. Scott; Kahn, Stephen; Palmer, Robert; Trbojevic, Dejan; Johnstone, Carol; Keil, Eberhard; Aiba, Masamitsu; Machida, Shinji; Mori, Yoshiharu; Ogitsu, Toru; Ohmori, Chihiro; Sessler, Andrew; Koscielniak, Shane

    2003-01-01

    Due to their finite lifetime, muons must be accelerated very rapidly. It is challenging to make the magnets ramp fast enough to accelerate in a synchrotron, and accelerating in a linac is very expensive. One can use a recirculating accelerator (like CEBAF), but one needs a different arc for each turn, and this limits the number of turns one can use to accelerate, and therefore requires significant amounts of RF to achieve the desired energy gain. An alternative method for muon acceleration is using a fixed field alternating gradient (FFAG) accelerator. Such an accelerator has a very large energy acceptance (a factor of two or three), allowing one to use the same arc with a magnetic field that is constant over time. Thus, one can in principle make as many turns as one can tolerate due to muon decay, therefore reducing the RF cost without increasing the arc cost. This paper reviews the current status of research into the design of FFAGs for muon acceleration. Several current designs are described and compared. General design considerations are also discussed

  1. Accelerator-based BNCT.

    Science.gov (United States)

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. © 2013 Elsevier Ltd. All rights reserved.

  2. Applying the accelerator

    International Nuclear Information System (INIS)

    Barbalat, Oscar

    1989-01-01

    Originally developed as tools for frontier physics, particle accelerators provide valuable spinoff benefits in applied research and technology. These accelerator applications are the subject of a biennial meeting in Denton, Texas, but the increasing activity in this field resulted this year (5-9 September) in the first European Conference on Accelerators in Applied Research and Technology, organized by K. Bethge of Frankfurt's Goethe University. The meeting reflected a wide range of applications - ion beam analysis, exploitation of nuclear microbeams, accelerator mass spectrometry, applications of photonuclear reactions, ion beam processing, synchrotron radiation for semiconductor technology, specialized technology

  3. Superconducting linear accelerator cryostat

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Elkonin, B.V.; Sokolowski, J.S.

    1984-01-01

    A large vertical cryostat for a superconducting linear accelerator using quarter wave resonators has been developed. The essential technical details, operational experience and performance are described. (author)

  4. Trampoline effect in extreme ground motion.

    Science.gov (United States)

    Aoi, Shin; Kunugi, Takashi; Fujiwara, Hiroyuki

    2008-10-31

    In earthquake hazard assessment studies, the focus is usually on horizontal ground motion. However, records from the 14 June 2008 Iwate-Miyagi earthquake in Japan, a crustal event with a moment magnitude of 6.9, revealed an unprecedented vertical surface acceleration of nearly four times gravity, more than twice its horizontal counterpart. The vertical acceleration was distinctly asymmetric; the waveform envelope was about 1.6 times as large in the upward direction as in the downward direction, which is not explained by existing models of the soil response. We present a simple model of a mass bouncing on a trampoline to account for this asymmetry and the large vertical amplitude. The finding of a hitherto-unknown mode of strong ground motion may prompt major progress in near-source shaking assessments.

  5. Electrical Subsurface Grounding Analysis

    International Nuclear Information System (INIS)

    J.M. Calle

    2000-01-01

    The purpose and objective of this analysis is to determine the present grounding requirements of the Exploratory Studies Facility (ESF) subsurface electrical system and to verify that the actual grounding system and devices satisfy the requirements

  6. Linear accelerator for burner-reactor

    International Nuclear Information System (INIS)

    Batskikh, G.I.; Murin, B.P.; Fedotov, A.P.

    1991-01-01

    Future development of nuclear power engineering depends on the successful solution of two key problems of safety and utilization of high level radioactive wastes (HLRW) of atomic power plants (APP). Modern methods of HLRW treatment involve solidification, preliminary storing for a period of 30-50 years necessary for the decay of long-living nuclides and final burial in geological formations several hundred meters below the ground surface. The depth burial of the radioactive wastes requires complicated under ground constructions. It's very expensive and doesn't meet modern ecological requirements. Alternative modern and more reasonable methods of APP HLRW treatment are under consideration now. One of the methods involves separation of APP waste radionuclides for use in economy with subsequent transmutation of the long-living isotopes into the short-living ones by high-intensity neutron fluxes generated by proton accelerators. The installation intended for the long-living radionuclides transmutation into the short-living ones is called burner-reactor. It can be based on the continuous regime proton accelerator with 1.5 GeV energy, 0.3 A current and beam mean power of 450 MW. The preferable type of the proton accelerator with the aforementioned parameters is the linear accelerator

  7. Characteristics of near-field earthquake ground motion

    International Nuclear Information System (INIS)

    Kim, H. K.; Choi, I. G.; Jeon, Y. S.; Seo, J. M.

    2002-01-01

    The near-field ground motions exhibit special response characteristics that are different from those of ordinary ground motions in the velocity and displacement response. This study first examines the characteristics of near-field ground motion depending on fault directivity and fault normal and parallel component. And the response spectra of the near field ground motion are statistically processed, and are compared with the Regulatory Guide 1.60 spectrum that is present design spectrum of the nuclear power plant. The response spectrum of the near filed ground motions shows large spectral velocity and displacement in the low frequency range. The spectral accelerations of near field ground motion are greatly amplified in the high frequency range for the rock site motions, and in the low frequency range for the soil site motions. As a result, the near field ground motion effects should be considered in the seismic design and seismic safety evaluation of the nuclear power plant structures and equipment

  8. The ground based plan

    International Nuclear Information System (INIS)

    1989-01-01

    The paper presents a report of ''The Ground Based Plan'' of the United Kingdom Science and Engineering Research Council. The ground based plan is a plan for research in astronomy and planetary science by ground based techniques. The contents of the report contains a description of:- the scientific objectives and technical requirements (the basis for the Plan), the present organisation and funding for the ground based programme, the Plan, the main scientific features and the further objectives of the Plan. (U.K.)

  9. Constructivist Grounded Theory?

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2012-06-01

    Full Text Available AbstractI refer to and use as scholarly inspiration Charmaz’s excellent article on constructivist grounded theory as a tool of getting to the fundamental issues on why grounded theory is not constructivist. I show that constructivist data, if it exists at all, is a very, very small part of the data that grounded theory uses.

  10. Communication, concepts and grounding

    NARCIS (Netherlands)

    van der Velde, Frank; van der Velde, F.

    2015-01-01

    This article discusses the relation between communication and conceptual grounding. In the brain, neurons, circuits and brain areas are involved in the representation of a concept, grounding it in perception and action. In terms of grounding we can distinguish between communication within the brain

  11. Accelerator Modeling with MATLAB Accelerator Toolbox

    International Nuclear Information System (INIS)

    2002-01-01

    This paper introduces Accelerator Toolbox (AT)--a collection of tools to model storage rings and beam transport lines in the MATLAB environment. The objective is to illustrate the flexibility and efficiency of the AT-MATLAB framework. The paper discusses three examples of problems that are analyzed frequently in connection with ring-based synchrotron light sources

  12. Santa Fe Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    The 10th USA National Particle Accelerator Conference was hosted this year by the Los Alamos National Laboratory in Santa Fe from 21-23 March. It was a resounding success in emphasizing the ferment of activity in the accelerator field. About 900 people registered and about 500 papers were presented in invited and contributed talks and poster sessions

  13. Relativistic Shock Acceleration

    International Nuclear Information System (INIS)

    Duffy, P.; Downes, T.P.; Gallant, Y.A.; Kirk, J.G.

    1999-01-01

    In this paper we briefly review the basic theory of shock waves in relativistic hydrodynamics and magneto-hydrodynamics, emphasising some astrophysically interesting cases. We then present an overview of the theory of particle acceleration at such shocks describing the methods used to calculate the spectral indices of energetic particles. Recent results on acceleration at ultra-relativistic shocks are discussed. (author)

  14. CERN Accelerator School

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-01-15

    The CERN Accelerator School (CAS) offers a regular course on general accelerator physics. The first basic course was given in September 1984 at Orsay, France, and last September the advanced course was jointly organized by CAS, Oxford's Nuclear Physics Laboratory and the Rutherford Appleton Laboratory, and held at The Queen's College, Oxford.

  15. Accelerator for nuclear transmutation

    International Nuclear Information System (INIS)

    Schapira, J.P.

    1984-01-01

    A review on nuclear transmutation of radioactive wastes using particle accelerators is given. Technical feasibility, nuclear data, costs of various projects are discussed. It appears that one high energy accelerator (1500 MeV, 300 mA proton) could probably handle the amount of actinides generated by the actual French nuclear program [fr

  16. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960's to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore's Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail

  17. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1997-01-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at Lawrence Livermore National Laboratory (LLNL) from the early 1960s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400-ns pulses. The Advanced Test Accelerator (ATA) built at Livermore close-quote s Site 300 produced 10,000-Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and Lawrence Berkeley National Laboratory (LBNL). This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high-current, short-pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail. copyright 1997 American Institute of Physics

  18. Hamburg Accelerator Conference (2)

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Edmund J.N. [CERN Accelerator School (Switzerland)

    1992-11-15

    From 20-24 July, Hamburg welcomed the Fifteenth International Conference on High Energy Accelerators (HEACC). The HEACC Conference traditionally reviews the status of all major accelerator projects whether they are already running like clockwork, still in the construction phase, or waiting impatiently for financial approval.

  19. Charged particle accelerator

    International Nuclear Information System (INIS)

    Arakawa, Kazuo.

    1969-01-01

    An accelerator is disclosed having a device which permits the electrodes of an accelerator tube to be readily conditioned in an uncomplicated manner before commencing operation. In particle accelerators, it is necessary to condition the accelerator electrodes before a stable high voltage can be applied. Large current accelerators of the cockcroft-walton type require a complicated manual operation which entails applying to the electrodes a low voltage which is gradually increased to induce a vacuum discharge and then terminated. When the discharge attains an extremely low level, the voltage is again impressed and again raised to a high value in low current type accelerators, a high voltage power supply charges the electrodes once to induce discharge followed by reapplying the voltage when the vacuum discharge reaches a low level, according to which high voltage is automatically applied. This procedure, however, requires that the high voltage power supply be provided with a large internal resistance to limit the current to within several milliamps. The present invention connects a high voltage power supply and an accelerator tube through a discharge current limiting resistor wired in parallel with a switch. Initially, the switch is opened enabling the power supply to impress a voltage limited to a prescribed value by a suitably chosen resistor. Conditioning is effected by allowing the voltage between electrodes to increase and is followed by closing the switch through which high voltage is applied directly to the accelerator for operation. (K.J. Owens)

  20. Asia honours accelerator physicists

    CERN Multimedia

    2010-01-01

    "Steve Meyers of Cern and Jie Wei of Beijing's Tsinghua University are the first recipients of a new prize for particle physics. The pair were honoured for their contributions to numerous particle-accelerator projects - including Cern's Large Hadron Collider - by the Asian Committee for Future Accelerators (ACFA)..." (1 paragraph)

  1. Accelerators Beyond The Tevatron?

    Energy Technology Data Exchange (ETDEWEB)

    Lach, Joseph; /Fermilab

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  2. CERN Accelerator School

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The CERN Accelerator School (CAS) offers a regular course on general accelerator physics. The first basic course was given in September 1984 at Orsay, France, and last September the advanced course was jointly organized by CAS, Oxford's Nuclear Physics Laboratory and the Rutherford Appleton Laboratory, and held at The Queen's College, Oxford

  3. Thoughts on accelerator tubes

    International Nuclear Information System (INIS)

    Larson, J.D.

    1978-01-01

    A brief, subjective review is given of mechanisms that may be limiting electrostatic accelerator tubes to present levels of performance. Suggestions are made for attacking these limitations with the purpose of stimulating the thinking of designers and users of electrostatic accelerators

  4. KEK digital accelerator

    Directory of Open Access Journals (Sweden)

    T. Iwashita

    2011-07-01

    Full Text Available The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  5. Thoughts of accelerator tubes

    International Nuclear Information System (INIS)

    Larson, J.D.

    1977-01-01

    A brief, subjective review is given of mechanisms that may be limiting electrostatic accelerator tubes to present levels of performance. Suggestions are made for attacking these limitations with the purpose of stimulating the thinking of designers and users of electrostatic accelerators

  6. Racetrack linear accelerators

    International Nuclear Information System (INIS)

    Rowe, C.H.; Wilton, M.S. de.

    1979-01-01

    An improved recirculating electron beam linear accelerator of the racetrack type is described. The system comprises a beam path of four straight legs with four Pretzel bending magnets at the end of each leg to direct the beam into the next leg of the beam path. At least one of the beam path legs includes a linear accelerator. (UK)

  7. Linear Accelerator (LINAC)

    Science.gov (United States)

    ... uses microwave technology (similar to that used for radar) to accelerate electrons in a part of the accelerator called the "wave guide," then allows ... risk of accidental exposure is extremely low. top of page This page was ... No Please type your comment or suggestion into the following text ...

  8. Hamburg Accelerator Conference (2)

    International Nuclear Information System (INIS)

    Wilson, Edmund J.N.

    1992-01-01

    From 20-24 July, Hamburg welcomed the Fifteenth International Conference on High Energy Accelerators (HEACC). The HEACC Conference traditionally reviews the status of all major accelerator projects whether they are already running like clockwork, still in the construction phase, or waiting impatiently for financial approval

  9. Optimization of accelerator control

    International Nuclear Information System (INIS)

    Vasiljev, N.D.; Mozin, I.V.; Shelekhov, V.A.; Efremov, D.V.

    1992-01-01

    Expensive exploitation of charged particle accelerators is inevitably concerned with requirements of effectively obtaining of the best characteristics of accelerated beams for physical experiments. One of these characteristics is intensity. Increase of intensity is hindered by a number of effects, concerned with the influence of the volume charge field on a particle motion dynamics in accelerator's chamber. However, ultimate intensity, determined by a volume charge, is almost not achieved for the most of the operating accelerators. This fact is caused by losses of particles during injection, at the initial stage of acceleration and during extraction. These losses are caused by deviations the optimal from real characteristics of the accelerating and magnetic system. This is due to a number of circumstances, including technological tolerances on structural elements of systems, influence of measuring and auxiliary equipment and beam consumers' installations, placed in the closed proximity to magnets, and instability in operation of technological systems of accelerator. Control task consists in compensation of deviations of characteristics of magnetic and electric fields by optimal selection of control actions. As for technical means, automatization of modern accelerators allows to solve optimal control problems in real time. Therefore, the report is devoted to optimal control methods and experimental results. (J.P.N.)

  10. Accelerator breeder concept

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Fraser, J.S.; Garvey, P.M.

    1978-10-01

    The principal components and functions of an accelerator breeder are described. The role of the accelerator breeder as a possible long-term fissile production support facility for CANDU (Canada Deuterium Uranium) thorium advanced fuel cycles and the Canadian research and development program leading to such a facility are outlined. (author)

  11. Semiconductor acceleration sensor

    Science.gov (United States)

    Ueyanagi, Katsumichi; Kobayashi, Mitsuo; Goto, Tomoaki

    1996-09-01

    This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.

  12. Molecular ion acceleration using tandem accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Yuichi; Mizuhashi, Kiyoshi; Tajima, Satoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1996-12-01

    In TIARA compound beam radiation system, cluster beams have been produced using 3 MV tandem accelerator (9SDH-2) to supply them to various radiation on injection experiments. Till now, productions of C{sub 2-8}, Si{sub 2-4} and O{sub 2} and their accelerations up to 6 MeV have been succeeded. This study aimed at production and acceleration of B{sub 2-4} and LiF. Anion clusters were produced using the conventional ion source of cesium sputter type. The proportions of atoms, molecules and clusters elicited from the ion source were varied depending on the material`s properties and the operating conditions of ion source such as sample temperature, sputter voltage and the shape of sample. The anion clusters were accelerated toward the high voltage terminal in the center of tandem accelerator, leading to cations through losing their electrons by the collision to N{sub 2} gas in a charge conversion cell at the terminal. Positively charged cluster ions could be obtained by modulating the pressure of N{sub 2} gas. Thus, B{sub 2} (64 nA), B{sub 3} (4.4 nA) and B{sub 4} (2.7 nA) have been produced and their maximum survival probabilities were higher than those of carbon or silicon clusters. In addition, the relationship between beam current and gas pressure was investigated for Bn (n = 2-4) and LiF. (M.N.)

  13. Plasma based accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, Allen [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2015-05-01

    The concept of laser-induced plasma wakefields as a technique to accelerate charged particles was introduced 35 years ago as a means to go beyond the accelerating gradients possible with metallic cavities supporting radio frequency electromagnetic fields. Significant developments in laser technology have made possible the pulse intensity needed to realize this concept, and rapid progress is now underway in the realization of laser-driven plasma wakefield acceleration. It has also been realized that similar accelerating gradients can be produced by particle beams propagating in plasmas, and experimental programs have also been undertaken to study this possibility. Positive results have been achieved with electron-driven plasma wakefields, and a demonstration experiment with proton-driven wakefields is under construction at CERN. The concepts behind these different schemes and their pros and cons are described, as well as the experimental results achieved. An outlook for future practical uses of plasma based accelerators will also be given.

  14. TIARA electrostatic accelerator facility

    International Nuclear Information System (INIS)

    Tajima, Satoshi; Takada, Isao; Mizuhashi, Kiyoshi; Uno, Sadanori; Ohkoshi, Kiyonori; Nakajima, Yoshinori; Saitoh, Yuichi; Ishii, Yasuyuki; Kamiya, Tomihiro

    1996-07-01

    In order to promote the Advanced Radiation Technology Project, Japan Atomic Energy Research Institute constructed TIARA facility composed of four ion accelerators at Takasaki Radiation Chemistry Research Establishment for the period from 1988 to 1993. A 3MV tandem accelerator and an AVF cycrotron were completed in 1991 as the first phase of the construction, and a 3MV single-ended accelerator and a 400kV ion implanter were completed in 1993 as the second phase. Three electrostatic accelerators, the tandem, the single-ended and the implanter, were installed in the Multiple-beam facility of TIARA and have been operated for various experiments with using single, dual and triple beams without any serious trouble. This report describes the constructive works, machine performances, control systems, safety systems and accessory equipments of the electrostatic accelerators. (author)

  15. 2016 Accelerators meeting

    International Nuclear Information System (INIS)

    Spiro, Michel; Revol, Jean-Luc; Biarrotte, Jean-Luc; Napoly, Olivier; Jardin, Pascal; Chautard, Frederic; Thomas, Jean Charles; Petit, Eric

    2016-09-01

    The Accelerators meeting is organised every two years by the Accelerators division of the French Society of Physics (SFP). It brings together about 50 participants during a one-day meeting. The morning sessions are devoted to scientific presentations while the afternoon is dedicated to technical visits of facilities. This document brings together the available presentations (slides): 1 - Presentation of the Ganil - Grand accelerateur national d'ions lourds/Big national heavy-ion accelerator, Caen (Jardin, Pascal); 2 - Presentation of the Accelerators division of the French Society of Physics (Revol, Jean-Luc); 3 - Forward-looking and Prospective view (Napoly, Olivier); 4 - Accelerators at the National Institute of Nuclear and particle physics, situation, Forward-looking and Prospective view (Biarrotte, Jean-Luc); 5 - GANIL-SPIRAL2, missions and goals (Thomas, Jean Charles); 6 - The SPIRAL2 project (Petit, Eric)

  16. Collinear wake field acceleration

    International Nuclear Information System (INIS)

    Bane, K.L.F.; Chen, P.; Wilson, P.B.

    1985-04-01

    In the Voss-Weiland scheme of wake field acceleration a high current, ring-shaped driving bunch is used to accelerate a low current beam following along on axis. In such a structure, the transformer ratio, i.e., the ratio of maximum voltage that can be gained by the on-axis beam and the voltage lost by the driving beam, can be large. In contrast, it has been observed that for an arrangement in which driving and driven bunches follow the same path, and where the current distribution of both bunches is gaussian, the transformer ratio is not normally greater than two. This paper explores some of the possibilities and limitations of a collinear acceleration scheme. In addition to its application to wake field acceleration in structures, this study is also of interest for the understanding of the plasma wake field accelerator. 11 refs., 4 figs

  17. Standing wave accelerating structures

    International Nuclear Information System (INIS)

    Zavadtsev, A.A.; Zverev, B.V.; Sobepin, N.P.

    1984-01-01

    Accelerating ELA structures are considered and chosen for applied purposes of special designation. Accelerating structures with the standing wave are considered most effective for small size ELA. Designs and results of experimental investigation of two new accelerating structures are described. These are structures of the ''ring'' type with a decreased number of excitinq oscillation types and strucuture with transverse rods with a twice smaller transverse size as compared with the biperiodical structure with internal connection resonators. The accelerating biperiodical structures of the conventional type by the fact that the whole structure is not a linear chain of connected resonators, but a ring one. Model tests have shown that the homogeneous structure with transverse rods (STR) at the frequency of 2.8 GHz in the regime of the standing wave has an effective shunt resistance equalling 23 MOhm/m. It is shown that the small transverse size of biperiodic STR makes its application in logging linear electron accelerators

  18. Rigour and grounded theory.

    Science.gov (United States)

    Cooney, Adeline

    2011-01-01

    This paper explores ways to enhance and demonstrate rigour in a grounded theory study. Grounded theory is sometimes criticised for a lack of rigour. Beck (1993) identified credibility, auditability and fittingness as the main standards of rigour for qualitative research methods. These criteria were evaluated for applicability to a Straussian grounded theory study and expanded or refocused where necessary. The author uses a Straussian grounded theory study (Cooney, In press) to examine how the revised criteria can be applied when conducting a grounded theory study. Strauss and Corbin (1998b) criteria for judging the adequacy of a grounded theory were examined in the context of the wider literature examining rigour in qualitative research studies in general and grounded theory studies in particular. A literature search for 'rigour' and 'grounded theory' was carried out to support this analysis. Criteria are suggested for enhancing and demonstrating the rigour of a Straussian grounded theory study. These include: cross-checking emerging concepts against participants' meanings, asking experts if the theory 'fit' their experiences, and recording detailed memos outlining all analytical and sampling decisions. IMPLICATIONS FOR RESEARCH PRACTICE: The criteria identified have been expressed as questions to enable novice researchers to audit the extent to which they are demonstrating rigour when writing up their studies. However, it should not be forgotten that rigour is built into the grounded theory method through the inductive-deductive cycle of theory generation. Care in applying the grounded theory methodology correctly is the single most important factor in ensuring rigour.

  19. Analyzing radial acceleration with a smartphone acceleration sensor

    Science.gov (United States)

    Vogt, Patrik; Kuhn, Jochen

    2013-03-01

    This paper continues the sequence of experiments using the acceleration sensor of smartphones (for description of the function and the use of the acceleration sensor, see Ref. 1) within this column, in this case for analyzing the radial acceleration.

  20. Collective ion acceleration

    International Nuclear Information System (INIS)

    Godfrey, B.B.; Faehl, R.J.; Newberger, B.S.; Shanahan, W.R.; Thode, L.E.

    1977-01-01

    Progress achieved in the understanding and development of collective ion acceleration is presented. Extensive analytic and computational studies of slow cyclotron wave growth on an electron beam in a helix amplifier were performed. Research included precise determination of linear coupling between beam and helix, suppression of undesired transients and end effects, and two-dimensional simulations of wave growth in physically realizable systems. Electrostatic well depths produced exceed requirements for the Autoresonant Ion Acceleration feasibility experiment. Acceleration of test ions to modest energies in the troughs of such waves was also demonstrated. Smaller efforts were devoted to alternative acceleration mechanisms. Langmuir wave phase velocity in Converging Guide Acceleration was calculated as a function of the ratio of electron beam current to space-charge limiting current. A new collective acceleration approach, in which cyclotron wave phase velocity is varied by modulation of electron beam voltage, is proposed. Acceleration by traveling Virtual Cathode or Localized Pinch was considered, but appears less promising. In support of this research, fundamental investigations of beam propagation in evacuated waveguides, of nonneutral beam linear eigenmodes, and of beam stability were carried out. Several computer programs were developed or enhanced. Plans for future work are discussed

  1. Multicavity proton cyclotron accelerator

    Directory of Open Access Journals (Sweden)

    J. L. Hirshfield

    2002-08-01

    Full Text Available A mechanism for acceleration of protons is described, in which energy gain occurs near cyclotron resonance as protons drift through a sequence of rotating-mode TE_{111} cylindrical cavities in a strong nearly uniform axial magnetic field. Cavity resonance frequencies decrease in sequence from one another with a fixed frequency interval Δf between cavities, so that synchronism can be maintained between the rf fields and proton bunches injected at intervals of 1/Δf. An example is presented in which a 122 mA, 1 MeV proton beam is accelerated to 961 MeV using a cascade of eight cavities in an 8.1 T magnetic field, with the first cavity resonant at 120 MHz and with Δf=8 MHz. Average acceleration gradient exceeds 40 MV/m, average effective shunt impedance is 223 MΩ/m, but maximum surface field in the cavities does not exceed 7.2 MV/m. These features occur because protons make many orbital turns in each cavity and thus experience acceleration from each cavity field many times. Longitudinal and transverse stability appear to be intrinsic properties of the acceleration mechanism, and an example to illustrate this is presented. This acceleration concept could be developed into a proton accelerator for a high-power neutron spallation source, such as that required for transmutation of nuclear waste or driving a subcritical fission burner, provided a number of significant practical issues can be addressed.

  2. The miniature accelerator

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    The image that most people have of CERN is of its enormous accelerators and their capacity to accelerate particles to extremely high energies. But thanks to some cutting-edge studies on beam dynamics and radiofrequency technology, along with innovative construction techniques, teams at CERN have now created the first module of a brand-new accelerator, which will be just 2 metres long. The potential uses of this miniature accelerator will include deployment in hospitals for the production of medical isotopes and the treatment of cancer. It’s a real David-and-Goliath story.   Serge Mathot, in charge of the construction of the "mini-RFQ", pictured with the first of the four modules that will make up the miniature accelerator. The miniature accelerator consists of a radiofrequency quadrupole (RFQ), a component found at the start of all proton accelerator chains around the world, from the smallest to the largest. The LHC is designed to produce very high-intensity beams ...

  3. Large electrostatic accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Jones, C.M.

    1984-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of large electrostatic accelerators designed to operate at terminal potentials of 20 MV or above. In this paper, the author briefly discusses the status of these new accelerators and also discusses several recent technological advances which may be expected to further improve their performance. The paper is divided into four parts: (1) a discussion of the motivation for the construction of large electrostatic accelerators, (2) a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, (3) a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and (4) a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year. Due to time and space constraints, discussion is restricted to consideration of only tandem accelerators.

  4. Large electrostatic accelerators

    International Nuclear Information System (INIS)

    Jones, C.M.

    1984-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of large electrostatic accelerators designed to operate at terminal potentials of 20 MV or above. In this paper, the author briefly discusses the status of these new accelerators and also discusses several recent technological advances which may be expected to further improve their performance. The paper is divided into four parts: (1) a discussion of the motivation for the construction of large electrostatic accelerators, (2) a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, (3) a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and (4) a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year. Due to time and space constraints, discussion is restricted to consideration of only tandem accelerators

  5. Superconductivity and future accelerators

    International Nuclear Information System (INIS)

    Danby, G.T.; Jackson, J.W.

    1963-01-01

    For 50 years particle accelerators employing accelerating cavities and deflecting magnets have been developed at a prodigious rate. New accelerator concepts and hardware ensembles have yielded great improvements in performance and GeV/$. The great idea for collective acceleration resulting from intense auxiliary charged-particle beams or laser light may or may not be just around the corner. In its absence, superconductivity (SC) applied both to rf cavities and to magnets opened up the potential for very large accelerators without excessive energy consumption and with other economies, even with the cw operation desirable for colliding beams. HEP has aggressively pioneered this new technology: the Fermilab single ring 1 TeV accelerator - 2 TeV collider is near the testing stage. Brookhaven National Laboratory's high luminosity pp 2 ring 800 GeV CBA collider is well into construction. Other types of superconducting projects are in the planning stage with much background R and D accomplished. The next generation of hadron colliders under discussion involves perhaps a 20 TeV ring (or rings) with 40 TeV CM energy. This is a very large machine: even if the highest practical field B approx. 10T is used, the radius is 10x that of the Fermilab accelerator. An extreme effort to get maximum GeV/$ may be crucial even for serious consideration of funding

  6. Accelerator programme at CAT

    International Nuclear Information System (INIS)

    Ramamurthi, S.S.

    1991-01-01

    The Accelerator Programme at the Centre for Advanced Technology (CAT), Indore, has very broad based concept under which all types of accelerators are to be taken up for design and fabrication. This centre will be housing a wide variety of accelerators to serve as a common facility for the universities, national laboratories in addition to laboratories under the Department of Atomic Energy. In the first phase of the programme, a series of electron accelerators are designed and fabricated. They are synchrotron radiation sources of 450 MeV (INDUS-I) and of 2 GeV (INDUS-II), microtron upto energy of 20 MeV, linear accelerator upto 20 MeV, and DC Accelerator for industrial irradiation upto 750 KeV and 20 KW. A proton accelerator of 300 MeV with 20 MeV linac injector is also designed. CAT is also developing a strong base for support technologies like ultra high vacuum, radio frequency and microwaves, DC pulsed and superconducting magnets, power supplies and controls etc. These technologies are very useful for other industrial applications also. To develop user groups to utilise INDUS-II synchrotron radiation source, a batch production of rotating Anode X-ray generators with power supplies has been initiated. So also, the sputter ion pumps, electron guns, turbo molecular pumps are brought into batch production. (author)

  7. New accelerator ideas

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    In the past, providing higher particle beam energies meant building bigger accelerators. It is now universally accepted that with the current generation of accelerator projects either under construction (such as LEP at CERN) or proposed (such as the Superconducting Super Collider in the US), conventional techniques are reaching their practical limit. With the growing awareness that progress in particle physics requires new methods to accelerate particles, workshops and study groups are being set up across the world to search for ideas for the machines of tomorrow

  8. The auroral electron accelerator

    International Nuclear Information System (INIS)

    Bryant, D.A.; Hall, D.S.

    1989-01-01

    A model of the auroral electron acceleration process is presented in which the electrons are accelerated resonantly by lower-hybrid waves. The essentially stochastic acceleration process is approximated for the purposes of computation by a deterministic model involving an empirically derived energy transfer function. The empirical function, which is consistent with all that is known of electron energization by lower-hybrid waves, allows many, possibly all, observed features of the electron distribution to be reproduced. It is suggested that the process occurs widely in both space and laboratory plasmas. (author)

  9. ACCELERATORS: School report

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-12-15

    The expanded 1987 US Particle Accelerator School, held at Fermilab from 20 July to 14 August, included two two-week sessions. In the first, 101 students covered three university-style courses, listed as upper-division University of Chicago physics, covering the fundamentals of particle beams, magnetic optics and acceleration; relativistic electronics; and high energy storage rings. The 180 participants in the second session profited from 24 short courses presented by experts and covering a wide variety of topics in the physics and technology of particle accelerators.

  10. Hadron accelerators in medicine

    International Nuclear Information System (INIS)

    Amaldi, U.

    1996-01-01

    The application of hadron accelerators (protons and light ions) in cancer therapy is discussed. After a brief introduction on the rationale for the use of heavy charged particles in radiation therapy, a discussion is given on accelerator technology and beam delivery systems. Next, existing and planned facilities are briefly reviewed. The Italian Hadron-therapy Project is then described in some detail, with reference ro both the National Centre for Oncological Hadron-therapy and the design of different types of compact proton accelerators aimed at introducing proton therapy in a large umber of hospitals. (author)

  11. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    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.

  12. ACCELERATORS: School prizes

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Dedicated to its goal of encouraging scientists and students to work in the field of particle accelerators, the US Particle Accelerator School (operating since 1981) has switched to a new format. Starting this year, it will offer in alternate years basic accelerator physics plus advanced subjects in both university and symposium styles over four weeks. Expanding the school from two to four weeks gives additional flexibility, and undergraduate participation should be encouraged by university credits being offered for particular courses. In the intervening years, the school will organize six-day topical courses

  13. Accelerator Toolbox for MATLAB

    International Nuclear Information System (INIS)

    Terebilo, Andrei

    2001-01-01

    This paper introduces Accelerator Toolbox (AT)--a collection of tools to model particle accelerators and beam transport lines in the MATLAB environment. At SSRL, it has become the modeling code of choice for the ongoing design and future operation of the SPEAR 3 synchrotron light source. AT was designed to take advantage of power and simplicity of MATLAB--commercially developed environment for technical computing and visualization. Many examples in this paper illustrate the advantages of the AT approach and contrast it with existing accelerator code frameworks

  14. RF linear accelerators

    CERN Document Server

    Wangler, Thomas P

    2008-01-01

    Thomas P. Wangler received his B.S. degree in physics from Michigan State University, and his Ph.D. degree in physics and astronomy from the University of Wisconsin. After postdoctoral appointments at the University of Wisconsin and Brookhaven National Laboratory, he joined the staff of Argonne National Laboratory in 1966, working in the fields of experimental high-energy physics and accelerator physics. He joined the Accelerator Technology Division at Los Alamos National Laboratory in 1979, where he specialized in high-current beam physics and linear accelerator design and technology. In 2007

  15. Auroral electron acceleration

    International Nuclear Information System (INIS)

    Bryant, D.A.

    1989-10-01

    Two theories of auroral electron acceleration are discussed. Part 1 examines the currently widely held view that the acceleration is an ordered process in a quasi-static electric field. It is suggested that, although there are many factors seeming to support this theory, the major qualifications and uncertainties that have been identified combine to cast serious doubt over its validity. Part 2 is devoted to a relatively new interpretation in terms of stochastic acceleration in turbulent electric fields. This second theory, which appears to account readily for most known features of the electron distribution function, is considered to provide a more promising approach to this central question in magnetospheric plasma physics. (author)

  16. New accelerator ideas

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1985-05-15

    In the past, providing higher particle beam energies meant building bigger accelerators. It is now universally accepted that with the current generation of accelerator projects either under construction (such as LEP at CERN) or proposed (such as the Superconducting Super Collider in the US), conventional techniques are reaching their practical limit. With the growing awareness that progress in particle physics requires new methods to accelerate particles, workshops and study groups are being set up across the world to search for ideas for the machines of tomorrow.

  17. Advanced Accelerator Concepts

    Science.gov (United States)

    Siemann, Robert

    1998-04-01

    Current particle accelerators rely on conventional or superconducting radio frequency cavities to accelerate beams of protons or electrons for nuclear and particle research and for medical and materials science studies. New methods for achieving larger accelerating gradients have been proposed and are being studied. These include the use of high power lasers, laser driven plasmas, wake fields generated by intense low energy beams, and millimeter wavelength EM structures. The studies to date, and the prospects for practical applications of these new ideas will be discussed.

  18. Accelerators Spanish steps

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    In September, the CERN Accelerator School (CAS) held its third General Accelerator Physics Course, the venue this time being Salamanca, the oldest university in Spain. Spain, which rejoined CERN in 1982, now has a vigorous and steadily growing high energy physics community making substantial contributions to physics detector development and successfully involving Spanish industry. However the embryonic accelerator community cannot yet generate an equivalent level of activity, and this important channel for introducing new high technology into industry has yet to be fully exploited

  19. [Introduction to grounded theory].

    Science.gov (United States)

    Wang, Shou-Yu; Windsor, Carol; Yates, Patsy

    2012-02-01

    Grounded theory, first developed by Glaser and Strauss in the 1960s, was introduced into nursing education as a distinct research methodology in the 1970s. The theory is grounded in a critique of the dominant contemporary approach to social inquiry, which imposed "enduring" theoretical propositions onto study data. Rather than starting from a set theoretical framework, grounded theory relies on researchers distinguishing meaningful constructs from generated data and then identifying an appropriate theory. Grounded theory is thus particularly useful in investigating complex issues and behaviours not previously addressed and concepts and relationships in particular populations or places that are still undeveloped or weakly connected. Grounded theory data analysis processes include open, axial and selective coding levels. The purpose of this article was to explore the grounded theory research process and provide an initial understanding of this methodology.

  20. Accelerated Test Method for Corrosion Protective Coatings Project

    Science.gov (United States)

    Falker, John; Zeitlin, Nancy; Calle, Luz

    2015-01-01

    This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

  1. Joint International Accelerator School

    CERN Multimedia

    CERN Accelerator School

    2014-01-01

    The CERN and US Particle Accelerator Schools recently organised a Joint International Accelerator School on Beam Loss and Accelerator Protection, held at the Hyatt Regency Hotel, Newport Beach, California, USA from 5-14 November 2014. This Joint School was the 13th in a series of such schools, which started in 1985 and also involves the accelerator communities in Japan and Russia.   Photo courtesy of Alfonse Pham, Michigan State University.   The school attracted 58 participants representing 22 different nationalities, with around half from Europe and the other half from Asia and the Americas. The programme comprised 26 lectures, each of 90 minutes, and 13 hours of case study. The students were given homework each day and had an opportunity to sit a final exam, which counted towards university credit. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and quality of their lectures. Initial dis...

  2. Future accelerators: physics issues

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1977-11-01

    High energy physics of the future using future accelerators is discussed. The proposed machines and instruments, physics issues and opportunities including brief sketches of outstanding recent results, and the way the proposed machines address these issues are considered. 42 references

  3. Compact particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.

    2017-08-29

    A compact particle accelerator having an input portion configured to receive power to produce particles for acceleration, where the input portion includes a switch, is provided. In a general embodiment, a vacuum tube receives particles produced from the input portion at a first end, and a plurality of wafer stacks are positioned serially along the vacuum tube. Each of the plurality of wafer stacks include a dielectric and metal-oxide pair, wherein each of the plurality of wafer stacks further accelerate the particles in the vacuum tube. A beam shaper coupled to a second end of the vacuum tube shapes the particles accelerated by the plurality of wafer stacks into a beam and an output portion outputs the beam.

  4. The accelerator breeder

    International Nuclear Information System (INIS)

    Johansson, E.

    1986-01-01

    Interactions of high-energy particles with atomic nuclei, in particular heavy ones, leads to a strong emission of neutrons. Preferably these high-energy particles are protons or deuterons obtained from a linear accelerator. The neutrons emitted are utilized in the conversion of U238 to Pu239 or of Th232 to U233. The above is the basis of the accelerator breeder, a concept studied abroad in many variants. No such breeder has, however, so far been built, but there exists vast practical experience on the neutron production and on the linear accelerator. Some of the variants mentioned are described in the report, after a presentation of general characteristics for the particle-nucleus interaction and for the linear accelerator. (author)

  5. Accelerate Water Quality Improvement

    Science.gov (United States)

    EPA is committed to accelerating water quality improvement and minimizing negative impacts to aquatic life from contaminants and other stressors in the Bay Delta Estuary by working with California Water Boards to strengthen water quality improvement plans.

  6. Rejuvenating CERN's Accelerators

    CERN Multimedia

    2004-01-01

    In the coming years and especially in 2005, CERN's accelerators are going to receive an extensive renovation programme to ensure they will perform reliably and effectively when the LHC comes into service.

  7. Wake field acceleration experiments

    International Nuclear Information System (INIS)

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics? I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs

  8. Accelerated test program

    Science.gov (United States)

    Ford, F. E.; Harkness, J. M.

    1977-01-01

    A brief discussion on the accelerated testing of batteries is given. The statistical analysis and the various aspects of the modeling that was done and the results attained from the model are also briefly discussed.

  9. SSC accelerator availability allocation

    International Nuclear Information System (INIS)

    Dixon, K.T.; Franciscovich, J.

    1991-03-01

    Superconducting Super Collider (SSC) operational availability is an area of major concern, judged by the Central Design Group to present such risk that use of modern engineering tools would be essential to program success. Experience has shown that as accelerator beam availability falls below about 80%, efficiency of physics experiments degrades rapidly due to inability to maintain adequate coincident accelerator and detector operation. For this reason, the SSC availability goal has been set at 80%, even though the Fermi National Accelerator Laboratory accelerator, with a fraction of the SSC's complexity, has only recently approached that level. This paper describes the allocation of the top-level goal to part-level reliability and maintainability requirements, and it gives the results of parameter sensitivity studies designed to help identify the best approach to achieve the needed system availability within funding and schedule constraints. 1 ref., 12 figs., 4 tabs

  10. IAE pulsed electrostatic accelerator

    International Nuclear Information System (INIS)

    Afanas'ev, V.P.; Ganzhelyuk, M.L.; Kozlov, L.D.; Koltypin, E.A.; Molchanov, Yu.D.; Otroshchenko, G.A.; Yan'kov, G.B.

    1976-01-01

    The modernized pulse electrostatic accelerator using the klystron ion grouping and the beam interruption system prior to acceleration is described. The accelerator is modernized in order to improve parameters of a current pulse and to decrease the background in the measurement room. The ion beam of needed dimensions is obtained with the help of a high-frequency source and a beam grouping and deflection system. The general view of the beam grouping and deflection system is shown. The ion beam forming process is considered in detail. The modernized electrostatic accelerator permits to obtain a pulse current with a pulse length of 1.5 ns and an amplitude of 1.5 - 2 μA. With the repetition frequency of 2 MHz, the average target current is about 6 μA

  11. Ionization front accelerator

    International Nuclear Information System (INIS)

    Olson, C.L.

    1975-01-01

    In a recently proposed linear collective accelerator, ions are accelerated in a steep, moving potential well created at the head of an intense relativistic electron beam. The steepness of the potential well and its motion are controlled by the external ionization of a suitable background gas. Calculations concerning optimum choices for the background gas and the ionization method are presented; a two-step photoionization process employing Cs vapor is proposed. In this process, a super-radiant light source is used to excite the gas, and a UV laser is used to photoionize the excited state. The appropriate line widths and coupled ionization growth rate equations are discussed. Parameter estimates are given for a feasibility experiment, for a 1 GeV proton accelerator, and for a heavy ion accelerator (50 MeV/nucleon uranium). (auth)

  12. HEAVY ION LINEAR ACCELERATOR

    Science.gov (United States)

    Van Atta, C.M.; Beringer, R.; Smith, L.

    1959-01-01

    A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

  13. Advances in electrostatic accelerators

    International Nuclear Information System (INIS)

    Wegner, H.E.

    1975-01-01

    Advances in the design and performance of electrostatic accelerators since 1969 are reviewed with special emphasis on the ''forefront'' accelerators that are currently leading in voltage capability. A comparison of the acceleration tube design offered by the National Electrostatics Corporation and the High Voltage Engineering Corporation is also made. Other methods of increasing heavy ion energy by means of dual foil stripping are discussed as well as the performance of a newly developed sputter ion source for the production of negative heavy ions with reliability and flexibility that greatly exceeds all other present systems. Finally, new developments in terms of both booster systems and very high voltage electrostatic accelerators (25 to 60 MV) are discussed. (U.S.)

  14. The Grounded Theory Bookshelf

    Directory of Open Access Journals (Sweden)

    Vivian B. Martin, Ph.D.

    2005-03-01

    Full Text Available Bookshelf will provide critical reviews and perspectives on books on theory and methodology of interest to grounded theory. This issue includes a review of Heaton’s Reworking Qualitative Data, of special interest for some of its references to grounded theory as a secondary analysis tool; and Goulding’s Grounded Theory: A practical guide for management, business, and market researchers, a book that attempts to explicate the method and presents a grounded theory study that falls a little short of the mark of a fully elaborated theory.Reworking Qualitative Data, Janet Heaton (Sage, 2004. Paperback, 176 pages, $29.95. Hardcover also available.

  15. Hot Ground Vibration Tests

    Data.gov (United States)

    National Aeronautics and Space Administration — Ground vibration tests or modal surveys are routinely conducted to support flutter analysis for subsonic and supersonic vehicles. However, vibration testing...

  16. Ground motion prediction models for Central America using data from 1972 to 2010

    International Nuclear Information System (INIS)

    Schmidt-Diaz, Victor

    2014-01-01

    The most important seismological aspects of Central America were reviewed. The predominant soil types and their origin were also studied. A description of the data used in aspects such as information sources, ranges of magnitude, hypocentral and epicentral distance, and earthquake classification according to their origin is presented. A procedure of soil classification for all sites is considered, based on the average spectral ratios obtained at each station, as well as in the geological maps and lithological descriptions. Attenuation equations are obtained for crustal earthquakes using data from Central America and for subduction earthquakes using records from Costa Rica. The linear functional form was used, taking the geometric mean of peak acceleration (GM PGA) or the geometric mean of the pseudo-spectral acceleration (GM PSA) obtained from the response spectra for 5% of damping, as the dependent variable. The moment magnitude, hypocentral distance, and soil type were used as independent variables. In the case of GM PSA, a total of 22 frequencies were considered. The results are compared with models proposed by other authors. In general, it is observed that values obtained in this paper are lower. The response spectra were also compared with those proposed by the Codigo Sismico de Costa Rica. For all cases, the selected least-squares one-step method is showed the highest stability of the results. (author) [es

  17. Feasibility studies of RFQ based 14C accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Guo Zhiyu; Liu Kexin; Yan Xueqing; Xie Yi; Fang Jiaxun; Chen Jiaer

    2007-01-01

    Electrostatic accelerators with terminal voltage less than 1 MeV have been successfully used for 14 C AMS. This contribution shows that a small RFQ accelerator may also be suitable for AMS 14 C measurements. A well-designed RFQ accelerator can realize a low energy spread and high isotopic selection with a length of less than 1 m and reasonable power consumption. Compared with small tandem accelerators, a RFQ does not need isolation gas and can accept much higher beam currents. Its stripper would be at ground potential and there would be no further acceleration after stripping, so the background from charge exchange processes should be lower. The RFQ design and system are described

  18. Optical signatures of discharges in parallel coupled DC accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, Rehim N.; Banerjee, Srutarshi; Acharya, S.N., E-mail: rehim@barc.gov.in [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India); and others

    2014-07-01

    Parallel coupled voltage multiplier based accelerator topologies offer advantages of better regulation and ripple compared to their series coupled counterparts for Industrial electron beam accelerators. During conditioning and operation these systems undergoes various types of electrical discharges. The discharge can be a direct spark over from the high voltage terminal to ground through SF{sub 6} insulation, vacuum breakdown in the accelerating tube maintained in the order of 10{sup -7} mbar pressure, or local discharge between corona guards which are used to couple RF power to the multiplier. There could be discharges in between dynodes of the accelerating tube. As the inter electrode discharges do not reflect in load current, detection of these conditions becomes very difficult. Optical discharge detection methods can be used effectively in this situation. Photo multiplier based optical discharge detection has been deployed in a 3 MeV DC accelerator. Characteristics of the optical signal received during conditioning phase have been presented in this paper. (author)

  19. Iteration and accelerator dynamics

    International Nuclear Information System (INIS)

    Peggs, S.

    1987-10-01

    Four examples of iteration in accelerator dynamics are studied in this paper. The first three show how iterations of the simplest maps reproduce most of the significant nonlinear behavior in real accelerators. Each of these examples can be easily reproduced by the reader, at the minimal cost of writing only 20 or 40 lines of code. The fourth example outlines a general way to iteratively solve nonlinear difference equations, analytically or numerically

  20. High energy medical accelerators

    International Nuclear Information System (INIS)

    Mandrillon, P.

    1990-01-01

    The treatment of tumours with charged particles, ranging from protons to 'light ions' (carbon, oxygen, neon), has many advantages, but up to now has been little used because of the absence of facilities. After the successful pioneering work carried out with accelerators built for physics research, machines dedicated to this new radiotherapy are planned or already in construction. These high energy medical accelerators are presented in this paper. (author) 15 refs.; 14 figs.; 8 tabs

  1. Vancouver Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1985-06-15

    Anyone who contends that particle physics is conducted in an ivory tower, not contributing to other fields of science or to humanity at large, should have attended the 1985 Particle Accelerator Conference in Vancouver. Over a thousand participants contributed 781 papers and only a fraction were actually related to accelerators for high energy physics. The majority of present developments are in the service of other fields of science, for alternative power sources, for medicine, for industrial applications, etc.

  2. A symmetrical rail accelerator

    International Nuclear Information System (INIS)

    Igenbergs, E.

    1991-01-01

    This paper reports on the symmetrical rail accelerator that has four rails, which are arranged symmetrically around the bore. The opposite rails have the same polarity and the adjacent rails the opposite polarity. In this configuration the radial force acting upon the individual rails is significantly smaller than in a conventional 2-rail configuration and a plasma armature is focussed towards the axis of the barrel. Experimental results indicate a higher efficiency compared to a conventional rail accelerator

  3. Ion optics for accelerators

    International Nuclear Information System (INIS)

    Enge, H.A.

    1974-01-01

    A review is given of ion-optic devices used in particle accelerators, including electrostatic lenses, magnetic quadrupoles, and deflecting magnets. Tube focusing in dc accelerators is also treated, and a novel scheme for shaping the electrodes to produce strong focusing is described. The concepts of emittance (phase space) and emittance conservation are briefly discussed. Chromatic and spatial aberrations are introduced, and it is shown how they can be calculated and sometimes substantially reduced. Some examples are given

  4. An active particle accelerator

    International Nuclear Information System (INIS)

    Goldman, T.

    1991-01-01

    Although a static charge is difficult to maintain on macroscopic particles, it is straightforward to construct a small object with a regularly oscillating electric dipole moment. For objects of a given size, one may then construct an accelerator by appropriately matching the frequency and separations of an external array of electrodes to this size. Physically feasible size ranges, an accelerator design, and possible applications of such systems are discussed. 8 refs., 9 figs

  5. Vancouver Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    Anyone who contends that particle physics is conducted in an ivory tower, not contributing to other fields of science or to humanity at large, should have attended the 1985 Particle Accelerator Conference in Vancouver. Over a thousand participants contributed 781 papers and only a fraction were actually related to accelerators for high energy physics. The majority of present developments are in the service of other fields of science, for alternative power sources, for medicine, for industrial applications, etc

  6. CEBAF Accelerator Achievements

    International Nuclear Information System (INIS)

    Chao, Y C; Drury, M; Hovater, C; Hutton, A; Krafft, G A; Poelker, M; Reece, C; Tiefenback, M

    2011-01-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  7. Collective field accelerator

    International Nuclear Information System (INIS)

    Luce, J.S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a ν/γ of approx. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam

  8. CEBAF: Accelerating cavities look good

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-09-15

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications.

  9. CEBAF: Accelerating cavities look good

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications

  10. JAERI 20 MV tandem accelerator

    International Nuclear Information System (INIS)

    Tsukada, Kineo; Harada, Kichinosuke

    1977-01-01

    Accelerators have been developed as the experimental apparatuses for the studies on nuclei and elementary particles. One direction of the development is the acceleration of protons and electrons to more and more high energy, and another direction is the acceleration of heavy ions up to uranium to several MeV up to several hundreds MeV. However recently, accelerators are used as the useful tools for the studies in wider fields. There are electrostatic acceleration and high frequency acceleration in ion acceleration, and at present, super-large accelerators are high frequency acceleration type. In Japan Atomic Energy Research Institute, it was decided in 1975 to construct an electrostatic accelerator of tandem type in order to accelerate heavy ions. In case of the electrostatic acceleration, the construction is relatively simple, the acceleration of heavy ions is easy, the property of the ion beam is very good, and the energy is stable. Especially, the tandem type is convenient for obtaining high energy. The tandem accelerator of 20 MV terminal voltage was ordered from the National Electrostatics Corp., USA, and is expected to be completed in 1978. The significance of heavy ion acceleration in the development and research of atomic energy, tandem van de Graaff accelerators, the JAERI 20MV tandem accelerator, and the research project with this accelerator are described. (Kako, I.)

  11. APT accelerator technology

    International Nuclear Information System (INIS)

    Schneider, J. David

    1996-01-01

    The proposed accelerator production of tritium (APT) project requires an accelerator that provides a cw proton beam of 100 m A at 1300 MeV. Since the majority of the technical risk of a high-current cw (continuous-wave, 100% DF) accelerator resides in the low-energy section, Los Alamos is building a 20 MeV duplicate of the accelerator front end to confirm design codes, beam performance, and demonstrate operational reliability. We report on design details of this low-energy demonstration accelerator (LEDA) and discuss the integrated design of the full accelerator for the APT plant. LEDA's proton injector is under test and has produced more than 130 mA at 75 keV. Fabrication is proceeding on a 6.7- MeV, 8-meter-long RFQ, and detailed design is underway on coupled-cavity drift-tube linac (CCDTL) structures. In addition, detailed design and technology experiments are underway on medium-beta superconducting cavities to assess the feasibility of replacing the conventional (room-temperature copper) high-energy linac with a linac made of niobium superconducting RF cavities. (author)

  12. Laser wakefield acceleration

    International Nuclear Information System (INIS)

    Esarey, E.; Ting, A.; Sprangle, P.

    1989-01-01

    The laser wakefield accelerator (LWFA) is a novel plasma based electron acceleration scheme which utilizes a relativistic optical guiding mechanism for laser pulse propagation. In the LWFA, a short, high power, single frequency laser pulse is propagated through a plasma. As the laser pulse propagates, its radial and axial ponderomotive forces nonresonantly generate large amplitude plasma waves (wakefields) with a phase velocity equal to the group velocity of the pulse. A properly phased electron bunch may then be accelerated by the axial wakefield and focused by the transverse wakefield. Optical guiding of the laser pulse in the plasma is necessary in order to achieve high energies in a single stage of acceleration. At sufficiently high laser powers, optical guiding may be achieved through relativistic effects associated with the plasma electrons. Preliminary analysis indicates that this scheme may overcome some of the difficulties present in the plasma beat wave accelerator and in the plasma wakefield accelerator. Analytical and numerical calculations are presented which study both laser pulse propagation within a plasma as well as the subsequent generation of large amplitude plasma waves. In addition, the generation of large amplitude plasma waves in regimes where the plasma waves become highly nonlinear is examined

  13. 36Chlorine accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator. RSP-12

    International Nuclear Information System (INIS)

    Surendran, P.; Shrivastava, A.; Gupta, A.K.; Nair, J.P.; Yadav, M.L.; Gore, J.A.; Sparrow, H.; Bhagwat, P.V.; Kailas, S.; Kale, R.M.; Hemalatha, M.

    2007-01-01

    Accelerator mass spectrometry (AMS) is an ultra sensitive means of counting individual atoms having sufficiently long half life and available in small amount. The 14 UD Pelletron Accelerator is an ideal machine to carry out AMS studies with heavy isotopes like 36 Cl and 129 I. Cosmogenic radio isotope 36 Cl is widely being detected using AMS as it has got applications in ground water research, radioactive waste management, atmospheric 36 Cl transport mechanism studies of Arctic Alpine ice core etc. As a part of the ongoing AMS programme at 14UD Pelletron Accelerator Facility, Mumbai, a segmented gas detector developed for identification of 36 Cl was tested for performance. Recently a beam chopper required for this measurement has been developed. 36 Cl measurements carried out to detect and measure the ratio of 36 Cl to 35 Cl in an irradiated sample and dated sample are reported in this paper

  14. Photon acceleration in laser wakefield accelerators

    International Nuclear Information System (INIS)

    Trines, R. M. G. M.

    2007-01-01

    If the index of a refraction of a dispersive medium, such as a plasma, changes in time, it can be used to change the frequency of light propagating through the medium. This effect is called photon acceleration. It has been predicted in both theory and simulations, and also been demonstrated experimentally for the case of moving ionization fronts in gases (the so-called ionization blueshift) as well as for laser-driven wakefields.Here, we present studies of photon acceleration in laser-driven plasma wakefields. The unique spectral characteristics of this process will be discussed, to distinguish it from e.g. photon acceleration by ionization fronts, frequency domain interferometry or self-phase modulation. The dynamics of the photons in laser-wakefield interaction are studied through both regular particle-in-cell and wave-kinetic simulations. The latter approach provides a powerful, versatile, and easy-to-use method to track the propagation of individual spectral components, providing new insight into the physics of laser-plasma interaction. Theory, simulations and experimental results will be brought together to provide a full understanding of the dynamics of a laser pulse in its own wakefield.Even though the wave-kinetic approach mentioned above has mainly been developed for the description of laser-plasma interaction, it can be applied to a much wider range of fast wave-slow wave interaction processes: Langmuir waves-ion acoustic waves, drift waves-zonal flow, Rossby waves-zonal flow, or even photons-gravitational waves. Several recent results in these areas will be shown, often with surprising results

  15. Accelerator business in Japan expanding

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Accelerators have become to be used increasingly in Japan in such fields as medicine, physics research and industry. This has caused stiff competition for market share by the manufacturers of accelerators. Electron beam accelerators for industrial use provide an indispensable means for adding values to products, for example, electric cables with incombustible insulators. Linear accelerators for the nondestructive inspection of nuclear components have been widely installed at equipment manufacturing plants. Active efforts have been exerted to develop small synchrotron radiation accelerators for next generation electronic industry. Cyclotrons for producing short life radioisotopes for medical diagnosis and electron beam accelerators for radiation therapy are also used routinely. The suppliers of accelerators include the companies manufacturing heavy electric machinery, heavy machinery and the engineering division of steelmakers. Accelerator physics is being formed, but universities do not yet offer the course regarding accelerators. Accelerator use in Japan and the trend of accelerator manufacturers are reported. (K.I.)

  16. Efektivitas Instagram Common Grounds

    OpenAIRE

    Wifalin, Michelle

    2016-01-01

    Efektivitas Instagram Common Grounds merupakan rumusan masalah yang diambil dalam penelitian ini. Efektivitas Instagram diukur menggunakan Customer Response Index (CRI), dimana responden diukur dalam berbagai tingkatan, mulai dari awareness, comprehend, interest, intentions dan action. Tingkatan respons inilah yang digunakan untuk mengukur efektivitas Instagram Common Grounds. Teori-teori yang digunakan untuk mendukung penelitian ini yaitu teori marketing Public Relations, teori iklan, efekti...

  17. Pesticides in Ground Water

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup

    1996-01-01

    Review af: Jack E. Barbash & Elizabeth A. Resek (1996). Pesticides in Ground Water. Distribution trends and governing factors. Ann Arbor Press, Inc. Chelsea, Michigan. pp 588.......Review af: Jack E. Barbash & Elizabeth A. Resek (1996). Pesticides in Ground Water. Distribution trends and governing factors. Ann Arbor Press, Inc. Chelsea, Michigan. pp 588....

  18. Beam transport through electrostatic accelerators and matching into post accelerators

    International Nuclear Information System (INIS)

    Larson, J.D.

    1986-01-01

    Ion beam transport through electrostatic acceleration is briefly reviewed. Topics discussed include injection, matching into the low-energy acceleration stage, matching from the terminal stripper into the high-energy stage, transport to a post accelerator, space charge, bunching isochronism, dispersion and charge selection. Beam transport plans for the proposed Vivitron accelerator are described. (orig.)

  19. The Grounded Theory Bookshelf

    Directory of Open Access Journals (Sweden)

    Dr. Alvita Nathaniel, DSN, APRN, BC

    2005-06-01

    Full Text Available The Grounded Theory Perspective III: Theoretical Coding, Barney G. Glaser (Sociology Press, 2005. Not intended for a beginner, this book further defi nes, describes, and explicates the classic grounded theory (GT method. Perspective III lays out various facets of theoretical coding as Glaser meticulously distinguishes classic GT from other subsequent methods. Developed many years after Glaser’s classic GT, these methods, particularly as described by Strauss and Corbin, adopt the grounded theory name and engender ongoing confusion about the very premises of grounded theory. Glaser distinguishes between classic GT and the adscititious methods in his writings, referring to remodeled grounded theory and its offshoots as Qualitative Data Analysis (QDA models.

  20. Communication, concepts and grounding.

    Science.gov (United States)

    van der Velde, Frank

    2015-02-01

    This article discusses the relation between communication and conceptual grounding. In the brain, neurons, circuits and brain areas are involved in the representation of a concept, grounding it in perception and action. In terms of grounding we can distinguish between communication within the brain and communication between humans or between humans and machines. In the first form of communication, a concept is activated by sensory input. Due to grounding, the information provided by this communication is not just determined by the sensory input but also by the outgoing connection structure of the conceptual representation, which is based on previous experiences and actions. The second form of communication, that between humans or between humans and machines, is influenced by the first form. In particular, a more successful interpersonal communication might require forms of situated cognition and interaction in which the entire representations of grounded concepts are involved. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Calibrating accelerometer sensor on android phone with Accelerograph TDL 303 QS for earthquake online recorder

    International Nuclear Information System (INIS)

    Riantana, R.; Darsono, D.; Azimut, H.B.; Triyono, A.

    2016-01-01

    Calibration of the android censor was done by placing the device in a mounting at side of accelerograph TDL 303 QS that will be a means of comparison. Leveling of both devices was set same, so that the state of the device can be assumed same anyway. Then applied vibrations in order to have the maximum amplitude value of both censor, so it can be found equality of the coefficient of proportionality both of them. The results on both devices obtain the Peak Ground Acceleration (PGA) as follows, on the x axis (EW) android censor is obtained PGA -2.4478145 gal than at TDL 303 QS obtained PGA -2.5504 gal, the y-axis (NS) on the censor android obtained PGA 3.0066964 gal than at TDL 303 QS obtained PGA 3.2073 gal, the z-axis (UD) on the android censor obtained PGA -14.0702377 gal than at TDL 303 QS obtained PGA -13.2927 gal, A correction value for android accelerometer censor is ± 0.1 gal for the x-axis (EW), ± 0.2 gal for the y-axis (NS), and ± 0.7 gal for the z-axis (UD). (paper)

  2. ORNL pellet acceleration program

    International Nuclear Information System (INIS)

    Foster, C.A.; Milora, S.L.

    1978-01-01

    The Oak Ridge National Laboratory (ORNL) pellet fueling program is centered around developing equipment to accelerate large pellets of solidified hydrogen to high speeds. This equipment will be used to experimentally determine pellet-plasma interaction physics on contemporary tokamaks. The pellet experiments performed on the Oak Ridge Tokamak (ORMAK) indicated that much larger, faster pellets would be advantageous. In order to produce and accelerate pellets of the order of 1 to 6 mm in diameter, two apparatuses have been designed and are being constructed. The first will make H 2 pellets by extruding a filament of hydrogen and mechanically chopping it into pellets. The pellets formed will be mechanically accelerated with a high speed arbor to a speed of 950 m/sec. This technique may be extended to speeds up to 5000 m/sec, which makes it a prime candidate for a reactor fueling device. In the second technique, a hydrogen pellet will be formed, loaded into a miniature rifle, and accelerated by means of high pressure hydrogen gas. This technique should be capable of speeds of the order of 1000 m/sec. While this technique does not offer the high performance of the mechanical accelerator, its relative simplicity makes it attractive for near-term experiments

  3. Accelerator development at Bates

    International Nuclear Information System (INIS)

    Sargent, C.P.

    1983-01-01

    The past year has seen the completion of a major expansion of the Bates Accelerator Laboratory. A second experimental hall, South Hall, and several magnetic spectrometers have been constructed. The accelerator's maximum energy has been raised from 400 to 750 MeV by means of beam recirculation. A current two-year project for the fabrication of an additional RF transmitter plus a 30% increase in RF peak power capability will increase energy further to ca. 1 GeV. During the same period pulse-to-pulse beam sharing between the high-resolution spectrometer area and South Hall will become available. In January 1981 the Laboratory submitted their ''Proposal for a Long-Range Expansion Program'' to DOE-NSF. The proposed development consists of three stages. Stage I calls for the addition of a pulse stretcher ring to furnish a CW beam to the South Hall beam lines. Additional experimental space for internal target experiments and photon tagging research are also included. Stage II increases the accelerator energy to 2.1 GeV (at 140 microamps) by means of a five-pass head-to-tail recirculator. Stage III is, at this time, a plan rather than a proposal. It increases accelerator energy to 4 GeV by extending the accelerator length and power and adds another pulse stretcher ring and three new experimental areas for the higher energy work. This paper discusses each of these stages in detail and recommends their funding and scheduling

  4. High energy plasma accelerators

    International Nuclear Information System (INIS)

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ω 0 , kappa 0 and ω 1 , kappa 1 shone on a plasma with frequency separation equal to the electron plasma frequency ω/sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ω/sub pe//e of the order of 1GeV/cm for a plasma density of 10 18 cm -3 through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed

  5. Linear induction accelerators

    International Nuclear Information System (INIS)

    Briggs, R.J.

    1986-06-01

    The development of linear induction accelerators has been motivated by applications requiring high-pulsed currents of charged particles at voltages exceeding the capability of single-stage, diode-type accelerators and at currents too high for rf accelerators. In principle, one can accelerate charged particles to arbitrarily high voltages using a multi-stage induction machine, but the 50-MeV, 10-kA Advanced Test Accelerator (ATA) at LLNL is the highest voltage machine in existence at this time. The advent of magnetic pulse power systems makes sustained operation at high-repetition rates practical, and this capability for high-average power is very likely to open up many new applications of induction machines in the future. This paper surveys the US induction linac technology with primary emphasis on electron machines. A simplified description of how induction machines couple energy to the electron beam is given, to illustrate many of the general issues that bound the design space of induction linacs

  6. Cable systems for experimental facilities in JAERI TANDEM ACCELERATOR BUILDING

    International Nuclear Information System (INIS)

    Tukihashi, Yoshihiro; Yoshida, Tadashi; Takekoshi, Eiko

    1979-03-01

    Measuring cable systems for experimental facilities in JAERI TANDEM ACCELERATOR BUILDING were completed recently. Measures are taken to prevent penetration of noises into the measuring systems. The cable systems are described in detail, including power supplies and grounding for the measuring systems. (author)

  7. Accelerators for atomic energy research

    International Nuclear Information System (INIS)

    Shibata, Tokushi

    1999-01-01

    The research and educational activities accomplished using accelerators for atomic energy research were studied. The studied items are research subjects, facility operation, the number of master theses and doctor theses on atomic energy research using accelerators and the future role of accelerators in atomic energy research. The strategy for promotion of the accelerator facility for atomic energy research is discussed. (author)

  8. Accelerators in Science and Technology

    CERN Document Server

    Kailas, S

    2002-01-01

    Accelerators built for basic research in frontier areas of science have become important and inevitable tools in many areas of science and technology. Accelerators are examples of science driven high technology development. Accelerators are used for a wide ranging applications, besides basic research. Accelerator based multidisciplinary research holds great promise

  9. Plasma-based accelerator structures

    International Nuclear Information System (INIS)

    Schroeder, Carl B.

    1999-01-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas

  10. Influence functionals and the accelerating detector

    International Nuclear Information System (INIS)

    Anglin, J.R.

    1993-01-01

    The influence functional is derived for a massive scalar field in the ground state, coupled to a uniformly accelerating DeWitt monopole detector in (D+1)-dimensional Minkowski space. This confirms the local nature of the Unruh effect, and provides an exact solution to the problem of the accelerating detector without invoking a nonstandard quantization. A directional detector is presented which is efficiently decohered by the scalar field vacuum, and which illustrates an important difference between the quantum mechanics of inertial and noninertial frames. From the results of these calculations, some comments are made regarding the possibility of establishing a quantum equivalence principle, so that the Hawking effect might be derived from the Unruh effect

  11. Ground motion measurement at Sefuri and Esashi area

    International Nuclear Information System (INIS)

    Sugahara, R.; Takeda, S.; Nozaki, M.; Yamaoka, H.; Yamashita, S.; Nakayama, Y.

    2008-02-01

    It is indispensable for the construction of the next-generation super high-energy accelerator to investigate the ground fluctuation and to get the information on the characteristics of ground vibration. KEK, ICEPP, and J-Power have cooperatively measured the usual tremor of various grounds. This report describes the results of the measurements carried out at the tunnel in Mise Expressway penetrating the Sefuri Mountains forming the boundary between Fukuoka and Saga prefectures and at the facility of Esashi earth tide measurement, National Astronomical Observatory. The comparison with past measurements on other area and the characteristics of wide band usual tremor of each area are also mentioned. (M.H.)

  12. Acceleration of magnetized plasma rings

    International Nuclear Information System (INIS)

    Hartman, D.; Eddleman, J.; Hammer, J.H.

    1982-01-01

    One scheme is considered, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focussing) during acceleration. Because the allowable acceleration force F/sub a/ = kappa U/sub m//R (kappa - 2 , the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency

  13. The 2011 Mineral, VA M5.8 Earthquake Ground Motions and Stress Drop: An Important Contribution to the NGA East Ground Motion Database

    Science.gov (United States)

    Cramer, C. H.; Kutliroff, J.; Dangkua, D.

    2011-12-01

    The M5.8 Mineral, Virginia earthquake of August 23, 2011 is the largest instrumentally recorded earthquake in eastern North America since the 1988 M5.9 Saguenay, Canada earthquake. Historically, a similar magnitude earthquake occurred on May 31, 1897 at 18:58 UCT in western Virginia west of Roanoke. Paleoseismic evidence for larger magnitude earthquakes has also been found in the central Virginia region. The Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), is ongoing at the Pacific Earthquake Engineering Research Center funded by the U.S. Nuclear Regulatory Commission, the U.S. Geological Survey, the Electric Power Research Institute, and the U.S. Department of Energy. The available recordings from the M5.8 Virginia are being added to the NGA East ground motion database. Close in (less than 100 km) strong motion recordings are particularly interesting for both ground motion and stress drop estimates as most close-in broadband seismometers clipped on the mainshock. A preliminary estimate for earthquake corner frequency for the M5.8 Virginia earthquake of ~0.7 Hz has been obtained from a strong motion record 57 km from the mainshock epicenter. For a M5.8 earthquake this suggests a Brune stress drop of ~300 bars for the Virginia event. Very preliminary comparisons using accelerometer data suggest the ground motions from the M5.8 Virginia earthquake agree well with current ENA ground motion prediction equations (GMPEs) at short periods (PGA, 0.2 s) and are below the GMPEs at longer periods (1.0 s), which is the same relationship seen from other recent M5 ENA earthquakes. We will present observed versus GMPE ground motion comparisons for all the ground motion observations and stress drop estimates from strong motion recordings at distances less than 100 km. A review of the completed NGA East ENA ground motion database will also be provided.

  14. Need for accelerating electrons

    International Nuclear Information System (INIS)

    Kerst, D.W.

    1987-01-01

    Photons for nuclear disintegration experiments were not abundantly available in the early days of nuclear physics, whereas accelerated ions led the way. When electrons could be accelerated into the 20--30 MeV range, they found application not only to nuclear disintegration of the elements of the periodic table but also to x-ray radiography and to deep therapy. Energies of interest for probing nuclear structure by electron scattering and for meson production followed soon after. The elementary nature of the electron has now made it a valuable tool for present day particle physics; and the synchrotron radiation, which is an obstacle for some accelerating processes, has become a much sought after source of photons for experiments at atomic structure energies

  15. Artificial seismic acceleration

    Science.gov (United States)

    Felzer, Karen R.; Page, Morgan T.; Michael, Andrew J.

    2015-01-01

    In their 2013 paper, Bouchon, Durand, Marsan, Karabulut, 3 and Schmittbuhl (BDMKS) claim to see significant accelerating seismicity before M 6.5 interplate mainshocks, but not before intraplate mainshocks, reflecting a preparatory process before large events. We concur with the finding of BDMKS that their interplate dataset has significantly more fore- shocks than their intraplate dataset; however, we disagree that the foreshocks are predictive of large events in particular. Acceleration in stacked foreshock sequences has been seen before and has been explained by the cascade model, in which earthquakes occasionally trigger aftershocks larger than themselves4. In this model, the time lags between the smaller mainshocks and larger aftershocks follow the inverse power law common to all aftershock sequences, creating an apparent acceleration when stacked (see Supplementary Information).

  16. Superconducting Accelerator Magnets

    CERN Document Server

    Mess, K H; Wolff, S

    1996-01-01

    The main topic of the book are the superconducting dipole and quadrupole magnets needed in high-energy accelerators and storage rings for protons, antiprotons or heavy ions. The basic principles of low-temperature superconductivity are outlined with special emphasis on the effects which are relevant for accelerator magnets. Properties and fabrication methods of practical superconductors are described. Analytical methods for field calculation and multipole expansion are presented for coils without and with iron yoke. The effect of yoke saturation and geometric distortions on field quality is studied. Persistent magnetization currents in the superconductor and eddy currents the copper part of the cable are analyzed in detail and their influence on field quality and magnet performance is investigated. Superconductor stability, quench origins and propagation and magnet protection are addressed. Some important concepts of accelerator physics are introduced which are needed to appreciate the demanding requirements ...

  17. Incineration by accelerator

    International Nuclear Information System (INIS)

    Cribier, M.; FIoni, G.; Legrain, R.; Lelievre, F.; Leray, S.; Pluquet, A.; Safa, H.; Spiro, M.; Terrien, Y.; Veyssiere, Ch.

    1997-01-01

    The use MOX fuel allows to hope a stabilization of plutonium production around 500 tons for the French park. In return, the flow of minor actinides is increased to several tons. INCA (INCineration by Accelerator), dedicated instrument, would allow to transmute several tons of americium, curium and neptunium. It could be able to reduce nuclear waste in the case of stopping nuclear energy use. This project needs: a protons accelerator of 1 GeV at high intensity ( 50 m A), a window separating the accelerator vacuum from the reactor, a spallation target able to produce 30 neutrons by incident proton, an incineration volume where a part of fast neutrons around the target are recovered, and a thermal part in periphery with flows at 2.10 15 n/cm 2 .s; a chemical separation of elements burning in thermal (americium) from the elements needing a flow of fast neutrons. (N.C.)

  18. Universality of accelerating change

    Science.gov (United States)

    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'.

  19. Future accelerators in Japan

    International Nuclear Information System (INIS)

    Toge, Nobu

    1993-01-01

    This paper presents a brief report on the present status of future accelerator projects at the National Laboratory for High Energy Physics (KEK), Japan. The KEK laboratory has been successfully operating the TRISTAN accelerator complex since 1986. It consists of a 2.5 GeV electron/positron linac, an 8 GeV Accumulation Ring (AR) and a 29 GeV Main Ring (MR). Concurrently with this operation, in response to recommendations by the Japanese High Energy Physics Committee, survey studies have been continued on new accelerator facilities at KEK. They have two major future projects, namely, the asymmetric e + e - B-factory based on TRISTAN (TRISTAN-II) and the Japan Linear Collider (JLC). The purpose of this paper is to outline those research activities and to present an update on their status

  20. Medical uses of accelerators

    International Nuclear Information System (INIS)

    Bradbury, J.N.

    1981-01-01

    A variety of particle accelerators have either potential or already demonstrated uses in connection with medically-related research, diagnosis, and treatment. For cancer radiotherapy, nuclear particles including protons, neutrons, heavy ions, and negative pi mesons have advantages compared to conventional radiations in terms of dose localization and/or biological effectiveness. Clinical evaluations of these particles are underway at a number of institutions. Accelerator-produced radionuclides are in widespread use for research and routine diagnostic purposes. Elemental analysis techniques with charged particles and neutrons are being applied to bone, blood, and other tissues. Finally, low-dose medical imaging can be accomplished with accelerated protons and heavy ions. The status and future of these programs are discussed

  1. JKJ accelerator timing system

    International Nuclear Information System (INIS)

    Ohmori, C.; Mori, Y.; Yoshii, M.; Yamamoto, M.

    2001-01-01

    The JKJ (JAERl-KEK Joint Project) accelerator complex consists of the linear accelerator, 3 GeV and 50 GeV synchrotrons. To minimize the beam loss during the beam transfer from the 3 GeV synchrotron to the 50 GeV one, the synchronization of the two RF system of the rings is very important. To reduce the background from the high and low momentum neutron, the neutron beam chopper will be employed. The 3 GeV RF will be also synchronized to the chopper timing when the beam goes to the neutron facility. The whole timing control system of these accelerators and chopper will be described. (author)

  2. Accelerators for therapy

    International Nuclear Information System (INIS)

    Pohlit, W.

    1994-01-01

    In the past decades circular and linear electron accelerators have been developed for clinical use in radiation therapy of tumors with the aim of achieving a high radiation dose in the tumor and as low as possible dose in the adjacent normal tissues. Today about one thousand accelerators are in medical use throughout the world and many hundred thousand patients are treated every day with accelerator-produced radiation. There exists, however, a large number of patients who cannot be treated satisfactorily in this way. New types of radiations such as neutrons, negative pions, protons and heavy ions were therefore tested recently. The clinical experience with these radiations and with new types of treatment procedures indicate that in future the use of a scanning beam of high energy protons might be optimal for the treatment of tumors. (orig.)

  3. Superconducting accelerator magnet design

    International Nuclear Information System (INIS)

    Wolff, S.

    1994-01-01

    Superconducting dipoles, quadrupoles and correction magnets are necessary to achieve the high magnetic fields required for big accelerators presently in construction or in the design phase. Different designs of superconducting accelerator magnets are described and the designs chosen at the big accelerator laboratories are presented. The most frequently used cosθ coil configuration is discussed in detail. Approaches for calculating the magnetic field quality including coil end fields are presented. Design details of the cables, coils, mechanical structures, yokes, helium vessels and cryostats including thermal radiation shields and support structures used in superconducting magnets are given. Necessary material properties are mentioned. Finally, the main results of magnetic field measurements and quench statistics are presented. (orig.)

  4. Accelerator technology in tokamaks

    International Nuclear Information System (INIS)

    Kustom, R.L.

    1977-01-01

    This article presents the similarities in the technology required for high energy accelerators and tokamak fusion devices. The tokamak devices and R and D programs described in the text represent only a fraction of the total fusion program. The technological barriers to producing successful, economical tokamak fusion power plants are as many as the plasma physics problems to be overcome. With the present emphasis on energy problems in this country and elsewhere, it is very likely that fusion technology related R and D programs will vigorously continue; and since high energy accelerator technology has so much in common with fusion technology, more scientists from the accelerator community are likely to be attracted to fusion problems

  5. Accelerating the culture change!

    Science.gov (United States)

    Klunk, S W; Panetta, J; Wooten, J

    1996-11-01

    Exide Electronics, a major supplier of uninterruptible power system equipment, embarked on a journey of changing a culture to improve quality, enhance customer responsiveness, and reduce costs. This case study examines the evolution of change over a period of seven years, with particular emphasis on the most recent years, 1992 through 1995. The article focuses on the Raleigh plant operations and describes how each succeeding year built on the successes and fixed the shortcomings of the prior years to accelerate the culture change, including corrective action and continuous improvement processes, organizational structures, expectations, goals, achievements, and pitfalls. The real challenge to changing the culture was structuring a dynamic approach to accelerate change! The presentation also examines how the evolutionary process itself can be created and accelerated through ongoing communication, regular feedback of progress and goals, constant evaluation and direction of the process, and measuring and paying for performance.

  6. Studies of accelerated compact toruses

    International Nuclear Information System (INIS)

    Hartman, C.W.; Eddleman, J.; Hammer, J.H.

    1983-01-01

    In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa - 2 , the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency

  7. Microelectromechanical acceleration-sensing apparatus

    Science.gov (United States)

    Lee, Robb M [Albuquerque, NM; Shul, Randy J [Albuquerque, NM; Polosky, Marc A [Albuquerque, NM; Hoke, Darren A [Albuquerque, NM; Vernon, George E [Rio Rancho, NM

    2006-12-12

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  8. CERN: Accelerator school

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Full text: Jyvaskyla, a university town in central Finland, was the setting for last year's General Accelerator School organized by the CERN Accelerator School. Well over a hundred students - more than for some time - followed two weeks of lectures on a broad spectrum of accelerator topics, the first step en route to becoming the designers, builders and operators of the surprisingly large number of, accelerators of all kinds either built or planned throughout Europe and further afield. This was the fifth such school organized by CAS in a biennial cycle which alternates this introductory level with more advanced tuition. The next, advanced, school will be from 20 October - 1 November, hosted by Athens University on the Greek Island of Rhodes. (Application details will become available in Spring but would-be participants should already reserve the dates.) After Finland, the CAS caravan moved to Benalmadena near Malaga in Spain where, together with Seville University, they organized one of the joint US-CERN schools held every two years and focusing on frontier accelerator topics. This time the subject was electron-positron factories - machines for high luminosity experiments in phi, tau-charm, beauty and Z physics. Experts from both sides of the Atlantic and from Japan shared their knowledge with an equally representative audience and probed the many intensity related phenomena which must be mastered to reach design performance. A number of these topics will receive extended coverage in the next specialist CAS School which is a repeat - by public demand - of the highly successful radiofrequency course held in Oxford in 1991. This school will be in Capri, Italy, with the support of the University of Naples from 29 April to 5 May. Details and application forms are now available by e-mail (CASRF@CERNVM.CERN.CH), by fax (+41 22 7824836) or from Suzanne von Wartburg, CERN Accelerator School, 1211 Geneva 23, Switzerland

  9. Interfacing to accelerator instrumentation

    International Nuclear Information System (INIS)

    Shea, T.J.

    1995-01-01

    As the sensory system for an accelerator, the beam instrumentation provides a tremendous amount of diagnostic information. Access to this information can vary from periodic spot checks by operators to high bandwidth data acquisition during studies. In this paper, example applications will illustrate the requirements on interfaces between the control system and the instrumentation hardware. A survey of the major accelerator facilities will identify the most popular interface standards. The impact of developments such as isochronous protocols and embedded digital signal processing will also be discussed

  10. Acceleration of polarized particles

    International Nuclear Information System (INIS)

    Buon, J.

    1992-05-01

    The spin kinetics of polarized beams in circular accelerators is reviewed in the case of spin-1/2 particles (electrons and protons) with emphasis on the depolarization phenomena. The acceleration of polarized proton beams in synchrotrons is described together with the cures applied to reduce depolarization, including the use of 'Siberian Snakes'. The in-situ polarization of electrons in storage rings due to synchrotron radiation is studied as well as depolarization in presence of ring imperfections. The applications of electron polarization to accurately calibrate the rings in energy and to use polarized beams in colliding-beam experiments are reviewed. (author) 76 refs., 19 figs., 1 tab

  11. Spallator - accelerator breeder

    International Nuclear Information System (INIS)

    Steinberg, M.

    1985-01-01

    The concept involves the use of spallation neutrons produced by interaction of a high energy proton (1 to 2 GeV) from a linear accelerator (LINAC) with a heavy metal target (uranium). The principal spallator concept is based on generating fissile fuel for use in LWR nuclear power plants. The spallator functions in conjunction with a reprocessing plant to regenerate and produce the Pu-239 or U-233 for fabrication into fresh LWR reactor fuel elements. Advances in proton accelerator technology has provided a solid base for predicting performance and optimizing the design of a reliable, continuous wave, high-current LINAC required by a fissile fuel production machine

  12. Accelerated cyclic corrosion tests

    Directory of Open Access Journals (Sweden)

    Prošek T.

    2016-06-01

    Full Text Available Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical phases. They are able to predict the material performance in service more correctly as documented on several examples. The use of NSS should thus be restricted for quality control.

  13. Electrostatic accelerator dielectrics

    International Nuclear Information System (INIS)

    Cooke, C.M.

    1989-05-01

    High voltage insulation problems in electrostatic accelerators are discussed. The aim of the analysis is to broaden the knowledge, highlight the characteristics of insulation technology and design strategies to improve use. The basic geometry of the insulation in accelerators is considered. A detailed description of each of the insulation regions is provided. The gas gap insulation of the terminal voltage is found to be sensitive to regions of high electric stress. In order to obtain satisfactory performance from solid support insulation, the attention is focused on the electric stress value and distribution. Potential subjects for discussion and further investigations are given

  14. Remarks on stochastic acceleration

    International Nuclear Information System (INIS)

    Graeff, P.

    1982-12-01

    Stochastic acceleration and turbulent diffusion are strong turbulence problems since no expansion parameter exists. Hence the problem of finding rigorous results is of major interest both for checking approximations and for reference models. Since we have found a way of constructing such models in the turbulent diffusion case the question of the extension to stochastic acceleration now arises. The paper offers some possibilities illustrated by the case of 'stochastic free fall' which may be particularly interesting in the context of linear response theory. (orig.)

  15. Monoenergetic laser wakefield acceleration

    Directory of Open Access Journals (Sweden)

    N. E. Andreev

    2000-02-01

    Full Text Available Three dimensional test particle simulations are applied to optimization of the plasma-channeled laser wakefield accelerator (LWFA operating in a weakly nonlinear regime. Electron beam energy spread, emittance, and luminosity depend upon the proportion of the electron bunch size to the plasma wavelength. This proportion tends to improve with the laser wavelength increase. We simulate a prospective two-stage ∼1GeV LWFA with controlled energy spread and emittance. The input parameters correspond to realistic capabilities of the BNL Accelerator Test Facility that features a picosecond-terawatt CO_{2} laser and a high-brightness electron gun.

  16. High intensity hadron accelerators

    International Nuclear Information System (INIS)

    Teng, L.C.

    1989-05-01

    This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics

  17. Photocathodes in accelerator applications

    International Nuclear Information System (INIS)

    Fraser, J.S.; Sheffield, R.L.; Gray, E.R.; Giles, P.M.; Springer, R.W.; Loebs, V.A.

    1987-01-01

    Some electron accelerator applications require bursts of short pulses at high microscopic repetition rates and high peak brightness. A photocathode, illuminated by a mode-locked laser, is well suited to filling this need. The intrinsic brightness of a photoemitter beam is high; experiments are under way at Los Alamos to study the brightness of short bunches with high space charge after acceleration. A laser-illuminated Cs 3 Sb photoemitter is located in the first rf cavity of an injector linac. Diagnostics include a pepper-pot emittance analyzer, a magnetic spectrometer, and a streak camera

  18. "Light sail" acceleration reexamined.

    Science.gov (United States)

    Macchi, Andrea; Veghini, Silvia; Pegoraro, Francesco

    2009-08-21

    The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for "optimal" values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple "light sail" model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.

  19. 'Light Sail' Acceleration Reexamined

    International Nuclear Information System (INIS)

    Macchi, Andrea; Veghini, Silvia; Pegoraro, Francesco

    2009-01-01

    The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for 'optimal' values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple 'light sail' model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.

  20. Accelerating time to benefit

    DEFF Research Database (Denmark)

    Svejvig, Per; Geraldi, Joana; Grex, Sara

    Despite the ubiquitous pressure for speed, our approaches to accelerate projects remain constrained to the old-fashioned understanding of the project as a vehicle to deliver products and services, not value. This article explores an attempt to accelerate time to benefit. We describe and deconstruct...... of the time. Although all cases valued speed and speed to benefit, and implemented most practices proposed by the methodology, only three of the five projects were more successful in decreasing time to speed. Based on a multi-case study comparison between these five different projects and their respective...

  1. Plasma wave accelerator. II

    International Nuclear Information System (INIS)

    Mori, W.; Joshi, C.; Dawson, J.M.

    1982-01-01

    It was shown that the insertion of a cross magnetic field prevents the particles from getting out of phase with the electric field of the plasma wave in the beat wave accelerator scheme. Thus, using a CO 2 laser, n/sub c//n/sub e/ = (ω 0 /ω/sub p/) 2 approx. 35, and a 300 kG magnetic field, electrons can be (in principle) accelerated to 100 GeV in 2 meters. For comparison without the magnetic field, the same energies may be obtained in a n/sub c//n/sub e/ approx. 10 5 plasma over a distance of 100 meters

  2. An accelerator technology legacy

    International Nuclear Information System (INIS)

    Heighway, E.A.

    1994-01-01

    Accelerator technology has been a major beneficiary of the investment made over the last decade. It is the intention of this paper to provide the reader with a glimpse of the broad nature of those advances. Development has been on a broad front and this paper can highlight only a few of those. Two spin-off applications will be outlined -- a concept for a compact, active, beam probe for solar body exploration and the concept for an accelerator-driven transmutation system for energy production

  3. Accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator. PD-1-2

    International Nuclear Information System (INIS)

    Bhagwat, P.V.

    2007-01-01

    Accelerator mass spectrometry (AMS) is an ultra sensitive means of counting individual atoms having sufficiently long half-life and available in small amount. The 14 UD Pelletron Accelerator is an ideal machine to carry out AMS studies with heavy isotopes like 36 Cl and 129 I. Cosmogenic radioisotope 36 Cl is widely being detected using AMS as it has got applications in ground water research, radioactive waste management, atmospheric 36 Cl transport mechanism studies of Arctic Alpine ice core etc . The AMS programme at the 14 UD Mumbai Pelletron Accelerator has taken off with the installation of the state of the art Terminal Potential Stabilizer setup and operation of the accelerator in Generating Volt Meter (GVM) mode. Feasibility studies have been carried out for detection/identification of 14 C from a charcoal sample and 3 He in natural Helium. As the primary interest of AMS programme at Mumbai Pelletron Accelerator is related to the cosmogenic nuclei, 36 Cl and 129 I, a segmented gas detector developed for identification of 36 Cl was tested for performance. Recently a beam chopper required for this measurement has also been developed

  4. Vehicle accelerated corrosion test procedures for automotive in Malaysia

    Directory of Open Access Journals (Sweden)

    Anuar Liza

    2017-01-01

    Full Text Available An accelerated corrosion test, known as proving ground accelerated test, is commonly performed by automotive manufacturers to evaluate the corrosion performance of a vehicle. The test combines corrosion and durability inputs to detect potential failures that may occur during in-service conditions. Currently, the test is conducted at an external test center overseas. Such test is aimed to simulate the effects of one year accelerated corrosion in severe corrosive environment of the north-east and south east of America. However, the test results obtained do not correlate with the actual corrosion conditions observed in the Malaysian market, which is likely attributed to the different test environment of the tropical climate of vehicles in service. Therefore, a vehicle accelerated corrosion test procedure that suits the Malaysian market is proposed and benchmarked with other global car manufacturers that have their own dedicated corrosion test procedure. In the present work, a test track is used as the corrosion test ground and consists of various types of roads for structural durability exposures. Corrosion related facilities like salt trough, mud trough and gravel road are constructed as addition to the existing facilities. The establishment of accelerated corrosion test facilities has contributed to the development of initial accelerated corrosion test procedure for the national car manufacturer. The corrosion exposure is monitored by fitting test coupons at the underbody of test vehicle using mass loss technique so that the desired corrosion rate capable of simulating the real time corrosion effects for its target market.

  5. Adding Theoretical Grounding to Grounded Theory: Toward Multi-Grounded Theory

    OpenAIRE

    Göran Goldkuhl; Stefan Cronholm

    2010-01-01

    The purpose of this paper is to challenge some of the cornerstones of the grounded theory approach and propose an extended and alternative approach for data analysis and theory development, which the authors call multi-grounded theory (MGT). A multi-grounded theory is not only empirically grounded; it is also grounded in other ways. Three different grounding processes are acknowledged: theoretical, empirical, and internal grounding. The authors go beyond the pure inductivist approach in GT an...

  6. Screening Approach to the Activation of Soil and Contamination of Groundwater at Linear Proton Accelerator Sites

    CERN Document Server

    Otto, Thomas

    The activation of soil and the contamination of groundwater at proton accelerator sites with the radionuclides 3H and 22Na are estimated with a Monte-Carlo calculation and a conservative soil- and ground water model. The obtained radionuclide concentrations show that the underground environment of future accelerators must be adequately protected against a migration of activation products. This study is of particular importance for the proton driver accelerator in the planned EURISOL facility.

  7. Synthesis of High-Frequency Ground Motion Using Information Extracted from Low-Frequency Ground Motion

    Science.gov (United States)

    Iwaki, A.; Fujiwara, H.

    2012-12-01

    Broadband ground motion computations of scenario earthquakes are often based on hybrid methods that are the combinations of deterministic approach in lower frequency band and stochastic approach in higher frequency band. Typical computation methods for low-frequency and high-frequency (LF and HF, respectively) ground motions are the numerical simulations, such as finite-difference and finite-element methods based on three-dimensional velocity structure model, and the stochastic Green's function method, respectively. In such hybrid methods, LF and HF wave fields are generated through two different methods that are completely independent of each other, and are combined at the matching frequency. However, LF and HF wave fields are essentially not independent as long as they are from the same event. In this study, we focus on the relation among acceleration envelopes at different frequency bands, and attempt to synthesize HF ground motion using the information extracted from LF ground motion, aiming to propose a new method for broad-band strong motion prediction. Our study area is Kanto area, Japan. We use the K-NET and KiK-net surface acceleration data and compute RMS envelope at four frequency bands: 0.5-1.0 Hz, 1.0-2.0 Hz, 2.0-4.0 Hz, .0-8.0 Hz, and 8.0-16.0 Hz. Taking the ratio of the envelopes of adjacent bands, we find that the envelope ratios have stable shapes at each site. The empirical envelope-ratio characteristics are combined with low-frequency envelope of the target earthquake to synthesize HF ground motion. We have applied the method to M5-class earthquakes and a M7 target earthquake that occurred in the vicinity of Kanto area, and successfully reproduced the observed HF ground motion of the target earthquake. The method can be applied to a broad band ground motion simulation for a scenario earthquake by combining numerically-computed low-frequency (~1 Hz) ground motion with the empirical envelope ratio characteristics to generate broadband ground motion

  8. Airfield Ground Safety

    National Research Council Canada - National Science Library

    Petrescu, Jon

    2000-01-01

    .... The system developed under AGS, called the Ground Safety Tracking and Reporting System, uses multisensor data fusion from in-pavement inductive loop sensors to address a critical problem affecting out nation's airports: runway incursions...

  9. Grounded meets floating

    Science.gov (United States)

    Walker, Ryan T.

    2018-04-01

    A comprehensive assessment of grounding-line migration rates around Antarctica, covering a third of the coast, suggests retreat in considerable portions of the continent, beyond the rates expected from adjustment following the Last Glacial Maximum.

  10. Ground water and earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Ts' ai, T H

    1977-11-01

    Chinese folk wisdom has long seen a relationship between ground water and earthquakes. Before an earthquake there is often an unusual change in the ground water level and volume of flow. Changes in the amount of particulate matter in ground water as well as changes in color, bubbling, gas emission, and noises and geysers are also often observed before earthquakes. Analysis of these features can help predict earthquakes. Other factors unrelated to earthquakes can cause some of these changes, too. As a first step it is necessary to find sites which are sensitive to changes in ground stress to be used as sensor points for predicting earthquakes. The necessary features are described. Recording of seismic waves of earthquake aftershocks is also an important part of earthquake predictions.

  11. A brief history of high power RF proton linear accelerators

    International Nuclear Information System (INIS)

    Browne, J.C.

    1996-01-01

    The first mention of linear acceleration was in a paper by G. Ising in 1924 in which he postulated the acceleration of positive ions induced by spark discharges which produced electric fields in gaps between a series of open-quotes drift tubesclose quotes. Ising apparently was not able to demonstrate his concept, most likely due to the limited state of electronic devices. Ising's work was followed by a seminal paper by R. Wideroe in 1928 in which he demonstrated the first linear accelerator. Wideroe was able to accelerate sodium or potassium ions to 50 keV of energy using drift tubes connected alternately to high frequency waves and to ground. Nuclear physics during this period was interested in accelerating protons, deuterons, electrons and alpha particles and not heavy ions like sodium or potassium. To accelerate the light ions required much higher frequencies than available at that time. So linear accelerators were not pursued heavily at that time. Research continued during the 1930s but the development of high frequency RF tubes for radar applications in World War 2 opened the potential for RF linear accelerators after the war. The Berkeley laboratory of E. 0. Lawrence under the leadership of Luis Alvarez developed a new linear proton accelerator concept that utilized drift tubes that required a full RF period to pass through as compared to the earlier concepts. This development resulted in the historic Berkeley 32 MeV proton linear accelerator which incorporated the open-quotes Alvarez drift tubeclose quotes as the basic acceleration scheme using surplus 200 MHz radar components

  12. Accelerators in the sky

    International Nuclear Information System (INIS)

    Setti, G.

    1977-01-01

    The author surveys the large body of evidence showing that there are very efficient mechanisms capable of accelerating particles to high energies under very different astrophysical conditions. The circumstances whereby huge amounts of relativistic and ultrarelativistic particles such as one finds in a) cosmic rays, b) supernova remnants and c) radio galaxies and quasars are produced are considered. (Auth.)

  13. Heavy ion accelerator GANIL

    International Nuclear Information System (INIS)

    1975-04-01

    This article presents GANIL, a large national heavy ion accelerator. The broad problems of nuclear physics, atomic physics, astrophysics and physics of condensed media which can be approached and studied with this machine are discussed first, after which the final construction project is described. The project comprises a circular injector, a separated sector cyclotron up beam stripper, and a second separated cyclotron downstream [fr

  14. Accelerating with industry

    International Nuclear Information System (INIS)

    Southworth, Brian

    1992-01-01

    At the end of March, Berlin was the scene of the third biennial European Particle Accelerator Conference (EPAC). It carried the usual news from the front-line machines in the high energy physics Laboratories and reports on progress with the latest technologies

  15. Two-beam accelerator

    International Nuclear Information System (INIS)

    Sessler, A.M.; Hopkins, D.B.

    1986-06-01

    The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field, induction accelerator units are placed periodically along the length of the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have a serious option for a 1 TeV x 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). Description is given of a first test at ELF with a seven-cell 2π/3 mode structure which without preconditioning and with a not-very-good vacuum nevertheless at 35 GHz yielded an average accelerating gradient of 180 MV/m

  16. Hamburg Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Edmund J.N. [CERN Accelerator School (Switzerland)

    1992-10-15

    From 20-24 July, Hamburg welcomed the Fifteenth International Conference on High Energy Accelerators (HEACC). A natural highlight was the recent commissioning success of the HERA electron-proton collider at Hamburg's DESY Laboratory and its first high energy electron-proton collision data. This gave the meeting the feel of a family event celebrating a newborn.

  17. The Bevalac accelerator

    International Nuclear Information System (INIS)

    Dacal, A.

    1989-01-01

    Presented are the characteristics of the Bevatron and SuperHilac heavy ion accelerators in a very general manner. Some aspects of their application in the field of biological medicine and some of the interesting results obtained in experiments on nuclear physics are mentioned. (Author). 20 refs, 2 figs, 2 tabs

  18. Radioisotope Dating with Accelerators.

    Science.gov (United States)

    Muller, Richard A.

    1979-01-01

    Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

  19. The CERN accelerator complex

    CERN Multimedia

    Mobs, Esma Anais

    2016-01-01

    The LHC is the last ring (dark blue line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

  20. The CERN accelerator complex

    CERN Multimedia

    Christiane Lefèvre

    2008-01-01

    The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

  1. Prospects for Accelerator Technology

    Science.gov (United States)

    Todd, Alan

    2011-02-01

    Accelerator technology today is a greater than US$5 billion per annum business. Development of higher-performance technology with improved reliability that delivers reduced system size and life cycle cost is expected to significantly increase the total accelerator technology market and open up new application sales. Potential future directions are identified and pitfalls in new market penetration are considered. Both of the present big market segments, medical radiation therapy units and semiconductor ion implanters, are approaching the "maturity" phase of their product cycles, where incremental development rather than paradigm shifts is the norm, but they should continue to dominate commercial sales for some time. It is anticipated that large discovery-science accelerators will continue to provide a specialty market beset by the unpredictable cycles resulting from the scale of the projects themselves, coupled with external political and economic drivers. Although fraught with differing market entry difficulties, the security and environmental markets, together with new, as yet unrealized, industrial material processing applications, are expected to provide the bulk of future commercial accelerator technology growth.

  2. Ion sources for accelerators

    International Nuclear Information System (INIS)

    Alton, G.D.

    1974-01-01

    A limited review of low charge sate positive and negative ion sources suitable for accelerator use is given. A brief discussion is also given of the concepts underlying the formation and extraction of ion beams. Particular emphasis is placed on the technology of ion sources which use solid elemental or molecular compounds to produce vapor for the ionization process

  3. BNL accelerator plans

    International Nuclear Information System (INIS)

    Lowenstein, D.I.

    1986-01-01

    The Brookhaven National Laboratory plan for high energy and heavy ion physics accelerator use for the next ten-year period is described. The two major initiatives are in the construction of the Relativistic Heavy Ion Collider and the upgrade of the Alternating Gradient Synchrotron to a ''Mini Kaon Factory''

  4. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

    Introduction to accelerator physics This course will take place in Budapest, Hungary, from 2 to 14 October 2016. It is now open for registration and further information can be found at: http://cas.web.cern.ch/cas/Hungary2016/Hungary-advert.html and http://indico.cern.ch/event/532397/.

  5. Accelerating with industry

    Energy Technology Data Exchange (ETDEWEB)

    Southworth, Brian

    1992-06-15

    At the end of March, Berlin was the scene of the third biennial European Particle Accelerator Conference (EPAC). It carried the usual news from the front-line machines in the high energy physics Laboratories and reports on progress with the latest technologies.

  6. Accelerating News Issue 5

    CERN Document Server

    Szeberenyi, A

    2013-01-01

    In this spring issue, we look at developments towards higher luminosity and higher energy colliders. We report on the technology developed for the remote powering of the LHC magnets and studies of diagnostics based on higher order mode port signals. We also inform you about the main outcome of the TIARA survey on market needs for accelerator scientists.

  7. Next generation of accelerators

    International Nuclear Information System (INIS)

    Richter, B.

    1979-01-01

    Existing high-energy accelerators are reviewed, along with those under construction or being designed. Finally, some of the physics issues which go into setting machine parameters, and some of the features of the design of next generation electron and proton machines are discussed

  8. Cockroft Walton accelerator prototype

    International Nuclear Information System (INIS)

    Hutapea, Sumihar.

    1976-01-01

    Prototype of a Cockroft Walton generator using ceramic and plastic capacitors is discussed. Compared to the previous generator, the construction and components are much more improved. Pralon is used for the high voltage insulation column and plastic is used as a dielectric material for the high voltage capacitor. Cockroft Walton generator is used as a high tension supply for an accelerator. (author)

  9. Accelerated product development

    NARCIS (Netherlands)

    Langerak, F.; Seth, J.N.; Malhotra, N.K.

    2011-01-01

    Accelerated product development is a competitive strategy that seeks to reduce the development cycle time of new products. However, there has been little theoretical advancement and empirical model testing in the identification of the conditions under which cycle time reduction is appropriate, the

  10. The ATOMKI Accelerator Center

    International Nuclear Information System (INIS)

    Biri, S.; Kormany, Z.; Berzi, I.; Hunyadi, M.

    2009-01-01

    In 2009 a new division was established in our institute: the ATOMKI Accelerator Center (AAC). Before this time the facilities and staff of AAC belonged to other departments of the institute. The re-organization however, was necessary. It was understood that the translocation of all the accelerators into a centralized unit is advantageous in numerous fields. Here we just mention some of them. The submission of any instrumentation type proposal (EU or domestic) will be easier and has a higher chance to be supported. The organization and distribution of the beamtimes will be more equal and optimal. The usage of the maintenance and spare tools can became better and cheaper. The operating staff (cca. 20 person) can serve at more than one accelerator and the teams can help each other. The accelerator center actually became a fourth new basic unit of the institute besides the three traditional scientific divisions (see the Atomki homepage for the organization chart). The following six main facilities belong to the accelerator center: Cyclotron; VdG-5 accelerator; VdG-1 accelerator; ECR ion source; Isotope separator; Tandetron (under installation). In figure 1 the placements of these machines are shown in an artistic 3D map of the Atomki. The table 1 summarizes the main parameters of the accelerators. More detailed technical specification of the machines can be found in the new homepage of the center. In 2009 all the accelerators operated as scheduled, safely and without major breakdowns. After the experiences in the first months it can be concluded that the new center works well both for technical and human point of views. In the next sub-chapters the 2009 operation and development details of the individual accelerators are summarized. Cyclotron operation. The operation of the cyclotron in 2009 was concentrated to the usual 9 months; January, July and August were reserved for maintenance and holidays. The overall working time of the accelerator was 2009 hours; the time

  11. Wakeless triple soliton accelerator

    International Nuclear Information System (INIS)

    Mima, K.; Ohsuga, T.; Takabe, H.; Nishihara, K.; Tajima, T.; Zaidman, E.; Horton, W.

    1986-09-01

    We introduce and analyze the concept of a wakeless triple soliton accelerator in a plasma fiber. Under appropriate conditions the triple soliton with two electromagnetic and one electrostatic waves in the beat-wave resonance propagates with velocity c leaving no plasma wake behind, while the phase velocity of the electrostatic wave is made also c in the fiber

  12. Hamburg Accelerator Conference

    International Nuclear Information System (INIS)

    Wilson, Edmund J.N.

    1992-01-01

    From 20-24 July, Hamburg welcomed the Fifteenth International Conference on High Energy Accelerators (HEACC). A natural highlight was the recent commissioning success of the HERA electron-proton collider at Hamburg's DESY Laboratory and its first high energy electron-proton collision data. This gave the meeting the feel of a family event celebrating a newborn

  13. The CERN accelerator complex

    CERN Multimedia

    Haffner, Julie

    2013-01-01

    The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

  14. Relativity and accelerator engineering

    International Nuclear Information System (INIS)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

    2017-09-01

    From a geometrical viewpoint, according to the theory of relativity, space and time constitute a four-dimensional continuum with pseudo-Euclidean structure. This has recently begun to be a practically important statement in accelerator physics. An X-ray Free Electron Laser (XFEL) is in fact the best, exciting example of an engineering system where improvements in accelerator technology makes it possible to develop ultrarelativistic macroscopic objects with an internal fine structure, and the theory of relativity plays an essential role in their description. An ultrarelativistic electron bunch modulated at nanometer-scale in XFELs has indeed a macroscopic finite-size of order of 10 μm. Its internal, collective structure is characterized in terms of a wave number vector. Here we will show that a four-dimensional geometrical approach, unusual in accelerator physics, is needed to solve problems involving the emission of radiation from an ultrarelativistic modulated electron beam accelerating along a curved trajectory. We will see that relativistic kinematics enters XFEL physics in a most fundamental way through the so-called Wigner rotation of the modulation wave number vector, which is closely associated to the relativity of simultaneity. If not taken into account, relativistic kinematics effects would lead to a strong qualitative disagreement between theory and experiments. In this paper, several examples of relativistic kinematics effects, which are important for current and future XFEL operation, are studied. The theory of relativity is applied by providing details of the clock synchronization procedure within the laboratory frame. This approach, exploited here but unusual in literature, is rather ''practical'', and should be acceptable to accelerator physicists.

  15. Menopause accelerates biological aging

    Science.gov (United States)

    Levine, Morgan E.; Lu, Ake T.; Chen, Brian H.; Hernandez, Dena G.; Singleton, Andrew B.; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E.; Quach, Austin; Kusters, Cynthia D. J.; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E.; Widschwendter, Martin; Ritz, Beate R.; Absher, Devin; Assimes, Themistocles L.; Horvath, Steve

    2016-01-01

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the “epigenetic clock”), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  16. Relativity and accelerator engineering

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Schenefeld (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2017-09-15

    From a geometrical viewpoint, according to the theory of relativity, space and time constitute a four-dimensional continuum with pseudo-Euclidean structure. This has recently begun to be a practically important statement in accelerator physics. An X-ray Free Electron Laser (XFEL) is in fact the best, exciting example of an engineering system where improvements in accelerator technology makes it possible to develop ultrarelativistic macroscopic objects with an internal fine structure, and the theory of relativity plays an essential role in their description. An ultrarelativistic electron bunch modulated at nanometer-scale in XFELs has indeed a macroscopic finite-size of order of 10 μm. Its internal, collective structure is characterized in terms of a wave number vector. Here we will show that a four-dimensional geometrical approach, unusual in accelerator physics, is needed to solve problems involving the emission of radiation from an ultrarelativistic modulated electron beam accelerating along a curved trajectory. We will see that relativistic kinematics enters XFEL physics in a most fundamental way through the so-called Wigner rotation of the modulation wave number vector, which is closely associated to the relativity of simultaneity. If not taken into account, relativistic kinematics effects would lead to a strong qualitative disagreement between theory and experiments. In this paper, several examples of relativistic kinematics effects, which are important for current and future XFEL operation, are studied. The theory of relativity is applied by providing details of the clock synchronization procedure within the laboratory frame. This approach, exploited here but unusual in literature, is rather ''practical'', and should be acceptable to accelerator physicists.

  17. Case study on ground water flow (8)

    International Nuclear Information System (INIS)

    1999-02-01

    The report comprises research activities made in fiscal year 1997 under the contract of Japan Nuclear Fuel Cycle Development Center and the main items are: (1) Evaluation of water permeability through discontinuous hard bedrock in deep strata in relevant with underground disposal of radioactive wastes, (2) Three dimensional analysis of permeated water in bedrock, including flow analysis in T ono district using neuro-network and modification of Evaporation Logging System, (3) Development of hydraulic tests and necessary equipment applicable to measurements of complex dielectric constants of contaminated soils using FUDR-V method, this giving information on soil component materials, (4) Investigation methods and modeling of hydraulics in deep strata, (5) Geological study of ground water using environmental isotopes such as 14 C, 36 Cl and 4 He, particularly measurement of ages of ground water using an accelerator-mass spectrometer, and (6) Re-submerging phenomena affecting the long-term geological stability. (S. Ohno)

  18. Case study on ground water flow (8)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-02-01

    The report comprises research activities made in fiscal year 1997 under the contract of Japan Nuclear Fuel Cycle Development Center and the main items are: (1) Evaluation of water permeability through discontinuous hard bedrock in deep strata in relevant with underground disposal of radioactive wastes, (2) Three dimensional analysis of permeated water in bedrock, including flow analysis in T ono district using neuro-network and modification of Evaporation Logging System, (3) Development of hydraulic tests and necessary equipment applicable to measurements of complex dielectric constants of contaminated soils using FUDR-V method, this giving information on soil component materials, (4) Investigation methods and modeling of hydraulics in deep strata, (5) Geological study of ground water using environmental isotopes such as {sup 14}C, {sup 36}Cl and {sup 4}He, particularly measurement of ages of ground water using an accelerator-mass spectrometer, and (6) Re-submerging phenomena affecting the long-term geological stability. (S. Ohno)

  19. Development of uniform hazard response spectra from accelerograms recorded on rock sites

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Kushwaha, H.S.

    2000-05-01

    Traditionally, the seismic design basis ground motion has been specified by response spectral shapes and the peak ground acceleration (PGA). The mean recurrence interval (MRI) is evaluated for PGA only. The present work has developed response spectra having the same MRI at all frequencies. This report extends the work of Cornell (on PGA) to consider an aerial source model and a general form of the spectral acceleration at various frequencies. The latter has been derived from a number of strong motion earthquake recorded on rock sites. Sensitivity of the results to the changes in various parameters has also been presented. These results will help to determine the seismic hazard at a given site and the associated uncertainties. (author)

  20. Yet Another Puzzle of Ground

    NARCIS (Netherlands)

    Korbmacher, J.

    2015-01-01

    We show that any predicational theory of partial ground that extends a standard theory of syntax and that proves some commonly accepted principles for partial ground is inconsistent. We suggest a way to obtain a consistent predicational theory of ground.

  1. Acceleration of polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1998-01-01

    The acceleration of polarized beams in circular accelerators is complicated by the numerous depolarizing spin resonances. Using a partial Siberian snake and a rf dipole that ensure stable adiabatic spin motion during acceleration has made it possible to accelerate polarized protons to 25 GeV at the Brookhaven AGS. Full Siberian snakes are being developed for RHIC to make the acceleration of polarized protons to 250 GeV possible. A similar scheme is being studied for the 800 GeV HERA proton accelerator

  2. Nonlinear dynamics in particle accelerators

    CERN Document Server

    Dilão, Rui

    1996-01-01

    This book is an introductory course to accelerator physics at the level of graduate students. It has been written for a large audience which includes users of accelerator facilities, accelerator physicists and engineers, and undergraduates aiming to learn the basic principles of construction, operation and applications of accelerators.The new concepts of dynamical systems developed in the last twenty years give the theoretical setting to analyse the stability of particle beams in accelerator. In this book a common language to both accelerator physics and dynamical systems is integrated and dev

  3. Unlimited Relativistic Shock Surfing Acceleration

    International Nuclear Information System (INIS)

    Ucer, D.; Shapiro, V. D.

    2001-01-01

    Nonrelativistic shock surfing acceleration at quasiperpendicular shocks is usually considered to be a preacceleration mechanism for slow pickup ions to initiate diffusive shock acceleration. In shock surfing, the particle accelerates along the shock front under the action of the convective electric field of the plasma flow. However, the particle also gains kinetic energy normal to the shock and eventually escapes downstream. We consider the case when ions are accelerated to relativistic velocities. In this case, the ions are likely to be trapped for infinitely long times, because the energy of bounce oscillations tends to decrease during acceleration. This suggests the possibility of unlimited acceleration by shock surfing

  4. Accelerator mass spectrometry at the Rossendorf 5 MV tandem accelerator

    International Nuclear Information System (INIS)

    Friedrich, M.; Buerger, W.; Curian, H.; Hartmann, B.; Hentschel, E.; Matthes, H.; Probst, W.; Seidel, M.; Turuc, S.; Hebert, D.; Rothe, T.; Stolz, W.

    1992-01-01

    The Rossendorf electrostatic accelerators (5 MV tandem accelerator and single ended 2 MV van de Graaff accelerator) are already used for ion beam analysis. The existing methods (RBS, PIXE, ERDA, NRA, nuclear microprobe and external beam) will be completed by introduction of Accelerator Mass Spectrometry (AMS). A short description of the Rossendorf AMS system is given and first experimental results are presented. (R.P.) 4 refs.; 6 figs

  5. SALOME: An Accelerator for the Practical Course in Accelerator Physics

    OpenAIRE

    Miltchev, Velizar; Riebesehl, Daniel; Roßbach, Jörg; Trunk, Maximilian; Stein, Oliver

    2014-01-01

    SALOME (Simple Accelerator for Learning Optics and the Manipulation of Electrons) is a short low energy linear electron accelerator built by the University of Hamburg. The goal of this project is to give the students the possibility to obtain hands-on experience with the basics of accelerator physics. In this contribution the layout of the device will be presented. The most important components of the accelerator will be discussed and an overview of the planned demonstration experiments will ...

  6. Seismic ground motion and hazard assessment of the Greater Accra Metropolitan Area, southeastern Ghana

    International Nuclear Information System (INIS)

    Amponsah, P.E.; Banoeng-Yakubo, B.K.; Asiedu, D.; Vaccari, F.; Panza, G.F.

    2008-08-01

    The seismic ground motion of the Greater Accra Metropolitan area has been computed and the hazard zones assessed using a deterministic hybrid approach based on the modal summation and finite difference methods. The seismic ground motion along four profiles located in the Greater Accra Metropolitan Area has been modelled using the 1939 earthquake of magnitude 6.5(M L ) as the scenario earthquake. Synthetic seismic waveforms from which parameters for engineering design such as peak ground acceleration, velocity and spectral amplifications have been produced along the geological cross sections. From the seismograms computed, the seismic hazard of the metropolis, expressed in terms of peak ground acceleration and peak ground velocity have been estimated. The peak ground acceleration estimated in the study ranges from 0.14 - 0.57 g and the peak ground velocity from 9.2 - 37.1cms -1 . The presence of low velocity sediments gave rise to high peak values and amplifications. The maximum peak ground accelerations estimated are located in areas with low velocity formations such as colluvium, continental and marine deposits. Areas in the metropolis underlain by unconsolidated sediments have been classified as the maximum damage potential zone and those underlain by highly consolidated geological materials are classified as low damage potential zone. The results of the numerical simulation have been extended to all areas in the metropolis with similar geological formation. (author)

  7. Mass spectrometry with accelerators.

    Science.gov (United States)

    Litherland, A E; Zhao, X-L; Kieser, W E

    2011-01-01

    As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

  8. IFMIF accelerators design

    International Nuclear Information System (INIS)

    Mosnier, A.; Ratzinger, U.

    2008-01-01

    The IFMIF requirement for 250 mA current of deuteron beams at a nominal energy of 40 MeV is met by means of two identical continuous wave (CW) 175 MHz linear accelerators running in parallel, each delivering a 125 mA, 40 MeV deuteron beam to the common target. This approach allows to stay within the current capability of present RF linac technology while providing operational redundancy in case of failure of one of the linacs. Each linac comprises a sequence of acceleration and beam transport/matching stages. The ion source generates a 140 mA deuteron beam at 100 keV. A low energy beam transport (LEBT) transfers the deuteron beam from the source to a radio frequency quadrupole (RFQ) cavity. The RFQ bunches and accelerates the 125 mA beam to 5 MeV. The RFQ output beam is injected through a matching section into a drift-tube-linac (DTL) where it is accelerated to the final energy of 40 MeV. In the reference design, the final acceleration stage is a conventional Alvarez-type DTL with post-couplers operating at room temperature. Operation of both the RFQ and the DTL at the same relatively low frequency is essential for accelerating the high current deuteron beam with low beam loss. The primary concern of the IFMIF linacs is the minimization of beam losses, which could limit their availability and maintainability due to excessive activation of the linac and irradiation of the environment. A careful beam dynamics design is therefore needed from the source to the target to avoid the formation of particle halo that could finally be lost in the linac or transfer lines. A superconducting solution for the high energy portion of the linac using, for example, CH-structure or coaxial-type resonators, could offer some advantages, in particular the reduction of operational costs. Careful beam dynamics simulations and comparison tests with beam during the EVEDA phase are however necessary in order to fully assess the technical feasibility of such alternative solutions

  9. Recent progress in particle accelerators

    International Nuclear Information System (INIS)

    Cole, F.T.; Mills, F.E.

    1988-01-01

    Many accelerators have also been built for medical radiography and therapy. Electron accelerators for this application are available commercially, using the electrons directly or bremsstrahlung photons. Neutrons produced by accelerator beams have also been used for therapy with considerable success, and several proton accelerators built for physics research have been adapted for direct therapy with protons. The first proton accelerator specifically for therapy is now being built. Separate from what might be called conventional accelerator technology, an entirely new field utilizing very highly pulsed power has been developed, and beams of short pulses of thousands or millions of amperes peak current in the MeV energy range are now available. These beams have important applications in high-energy particle acceleration, controlled fusion, industrial treatment of materials, and possibly in food preservation. All of these accelerators make use of external fields of acceleration. There is also vigorous research into new methods of acceleration, in many schemes making use of the intense accelerating fields, generated by laser beams or by plasma states of matter. This research has not as yet made traditional kinds of accelerators outmoded, but many workers hope that early in the next century there will be practical new acceleration methods making use of these very high fields. These developments are discussed in detail

  10. Acceleration of 14C beams in electrostatic accelerators

    International Nuclear Information System (INIS)

    Rowton, L.J.; Tesmer, J.R.

    1981-01-01

    Operational problems in the production and acceleration of 14 C beams for nuclear structure research in Los Alamos National Laboratory's Van de Graaff accelerators are discussed. Methods for the control of contamination in ion sources, accelerators and personnel are described. Sputter source target fabrication techniques and the relative beam production efficiencies of various types of bound particulate carbon sputter source targets are presented

  11. Development of uniform hazard response spectra for Tarapur, Trombay and Kakrapar sites

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Rao, K.S.; Kushwaha, H.S.

    2003-08-01

    Traditionally, the seismic design basis ground motion has been specified by normalised response spectral shapes and peak ground acceleration (PGA). The mean recurrence interval (MRI) used to be computed for PGA only. The present work develops uniform hazard response spectra i.e. spectra having the same MRI at all frequencies for Tarapur, Trombay and Kakrapar sites. These results determine the seismic hazard at the given site and the associated uncertainties. Typical examples are given to show the sensitivity of the results to changes in various parameters. (author)

  12. Adaptive control for accelerators

    International Nuclear Information System (INIS)

    Eaton, L.E.; Jachim, S.P.; Natter, E.F.

    1991-01-01

    This patent describes an adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity

  13. Accelerator research studies

    International Nuclear Information System (INIS)

    1993-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the second year of a three-year funding cycle. The program consists of the following three tasks: TASK A, ''Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' (P.I., M. Reiser); TASK B, ''Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' (Co-P.I.'s, W.W. Destler, M. Reiser, M.J. Rhee, and C.D. Striffler); TASK C, ''Study of a Gyroklystron High-Power Microwave Source for Linear Colliders,'' (Co-P.I.'s, V.L. Granatstein, W. Lawson, M. Reiser, and C.D. Striffler). In this report we document the progress that has been made during the past year for each of the three tasks

  14. Adaptive control for accelerators

    Science.gov (United States)

    Eaton, Lawrie E.; Jachim, Stephen P.; Natter, Eckard F.

    1991-01-01

    An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.

  15. Accelerator research studies

    International Nuclear Information System (INIS)

    1990-01-01

    This progress report for the Accelerator Research Studies program at the University of Maryland covers the second year (June 1, 1989 to May 31, 1990) of the current three-year contract period from June 1, 1988 to May 31, 1991, funded by the Department of Energy under Contract No. AC05-85ER40216. The research program is divided into three separate tasks, as follows: the study of Transport and Longitudinal Compression of Intense, High-Brightness Beams; the study of Collective Ion Acceleration by Intense Electron Beams and Pulse-Powered Plasma Focus; the study of Microwave Sources and Parameter Scaling for High-Frequency Linacs. This report consists of three sections in which the progress for each task is documented separately. An introduction and synopsis is presented at the beginning of the progress report for each task

  16. Review of ion accelerators

    International Nuclear Information System (INIS)

    Alonso, J.

    1990-06-01

    The field of ion acceleration to higher energies has grown rapidly in the last years. Many new facilities as well as substantial upgrades of existing facilities have extended the mass and energy range of available beams. Perhaps more significant for the long-term development of the field has been the expansion in the applications of these beams, and the building of facilities dedicated to areas outside of nuclear physics. This review will cover many of these new developments. Emphasis will be placed on accelerators with final energies above 50 MeV/amu. Facilities such as superconducting cyclotrons and storage rings are adequately covered in other review papers, and so will not be covered here

  17. Hardware Accelerated Simulated Radiography

    International Nuclear Information System (INIS)

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-01-01

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32 bit floating point texture capabilities to obtain validated solutions to the radiative transport equation for X-rays. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedra that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester. We show that the hardware accelerated solution is faster than the current technique used by scientists

  18. Review of accelerator instrumentation

    International Nuclear Information System (INIS)

    Pellegrin, J.L.

    1980-05-01

    Some of the problems associated with the monitoring of accelerator beams, particularly storage rings' beams, are reviewed along with their most common solutions. The various electrode structures used for the measurement of beam current, beam position, and the detection of the bunches' transverse oscillations, yield pulses with sub-nanosecond widths. The electronics for the processing of these short pulses involves wide band techniques and circuits usually not readily available from industry or the integrated circuit market: passive or active, successive integrations, linear gating, sample-and-hold circuits with nanosecond acquisition time, etc. This report also presents the work performed recently for monitoring the ultrashort beams of colliding linear accelerators or single-pass colliders. To minimize the beam emittance, the beam position must be measured with a high resolution, and digitized on a pulse-to-pulse basis. Experimental results obtained with the Stanford two-mile Linac single bunches are included

  19. Laser beam accelerator

    International Nuclear Information System (INIS)

    Tajima, T.; Dawson, J.M.

    1981-01-01

    Parallel intense photon (laser, microwave, etc.) beams /omega/sub //0, k/sub 0/ and /omega/sub //1, k/sub 1/ shone on a plasma with frequency separation equal to the plasma frequency /omega/sub //p is capable of accelerating plasma electrons to high energies in large flux. The photon beat excites through the forward Raman scattering large amplitude plasmons whose phase velocity is equal to (/omega/ /sub 0/-/omega/sub //1)/(k/sub 0/-k/sub 1/), close to c in an underdense plasma. The multiple forward Raman instability produces smaller and smaller frequency and group velocity of photons; thus the photons slow down in the plasma by emitting accelerated electrons (inverse Cherenkov process). 6 refs

  20. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  1. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2015-01-01

    This book by Helmut Wiedemann is a well-established, classic text, providing an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. The present 4th edition has been significantly revised, updated and expanded. The newly conceived Part I is an elementary introduction to the subject matter for undergraduate students. Part II gathers the basic tools in preparation of a more advanced treatment, summarizing the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part III is an extensive primer in beam dynamics, followed, in Part IV, by an introduction and description of the main beam parameters and including a new chapter on beam emittance and lattice design. Part V is devoted to the treatment of perturbations in beam dynamics. Part VI then discusses the details of charged particle acceleration. Parts VII and VIII introduce the more advanced topics of coupled beam dynamics and describe very intense bea...

  2. Accelerator research studies

    International Nuclear Information System (INIS)

    1992-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks

  3. Accelerators for cancer therapy

    International Nuclear Information System (INIS)

    Lennox, Arlene J.

    2000-01-01

    The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy

  4. Ion accelerators for space

    International Nuclear Information System (INIS)

    Slobodrian, R.J.; Potvin, L.

    1991-01-01

    The main purpose of the accelerators is to allow ion implantation in space stations and their neighborhoods. There are several applications of interest immediately useful in such environment: as ion engines and thrusters, as implanters for material science and for hardening of surfaces (relevant to improve resistance to micrometeorite bombardment of exposed external components), production of man made alloys, etc. The microgravity environment of space stations allows the production of substances (crystalline and amorphous) under conditions unknown on earth, leading to special materials. Ion implantation in situ of those materials would thus lead uninterruptedly to new substances. Accelerators for space require special design. On the one hand it is possible to forego vacuum systems simplifying the design and operation but, on the other hand, it is necessary to pay special attention to heat dissipation. Hence it is necessary to construct a simulator in vacuum to properly test prototypes under conditions prevailing in space

  5. Acceleration of microparticle

    CERN Document Server

    Shibata, H

    2002-01-01

    A microparticle (dust) ion source has been installed at the high voltage terminal of the 3.75 MV single ended Van de Graaff electrostatic accelerator and a beam line for microparticle experiments has been build at High Fluence Irradiation Facility (HIT) of Research Center for Nuclear Science and Technology, the University of Tokyo. Microparticle acceleration has been successful in obtaining expected velocities of 1-20 km/s or more for micron or submicron sized particles. Development of in situ dust detectors and analyzers on board satellites and spacecraft in the expected mass and velocity range of micrometeoroids and investigation of hypervelocity impact phenomena by using time of flight mass spectrometry, impact flash or luminescence measurement and scanning electron or laser microscope observation for metals, ceramics, polymers and semiconductors bombarded by micron-sized particles were started three years ago. (author)

  6. Analysis of seismic waves and strong ground motion

    International Nuclear Information System (INIS)

    Simpson, I.C.; Sutton, R.

    1976-10-01

    A number of Western USA earthquake acceleration-time histories concerning events of magnitude less than 6 are considered and their Fourier spectra calculated. An analysis of some of the simpler types of seismic wave is given in order to consider the generation of a spatially dependent acceleration-time history suitable for input into a soil-structure program of analysis. Such an acceleration-time history is required by a comprehensive analysis of soil-structure interaction since the conventionally assumed model of vertically propagating seismic waves, which give rise to three spatially independent ground motions, can lead to over-conservative estimates of the building response in the high frequency range. The possible application is discussed of a given component of a recorded acceleration-time history to the base of structure under the assumption of surface Rayleigh waves or obliquely incident P and SV bulk waves. (author)

  7. Hadron beams and accelerators

    International Nuclear Information System (INIS)

    Roser, T.

    1994-01-01

    There were four sessions on Hadron Beams and Accelerators with 7 talks on Siberian Snakes and spin rotators, 3 talks on polarization build-up of unpolarized beams in storage rings and 5. 9, and 3 talks on low, medium, and high energy polarimeters, respectively. In this paper I will briefly describe a few highlights from these sessions, giving emphasis to topics which I think will play an important role in the future

  8. ATLAS accelerator laboratory report

    International Nuclear Information System (INIS)

    Den Hartog, P.

    1986-01-01

    The operation of the ATLAS Accelerator is reported. Modifications are reported, including the installation of conductive tires for the Pelletron chain pulleys, installation of a new high frequency sweeper system at the entrance to the linac, and improvements to the rf drive ports of eight resonators to correct failures in the thermally conductive ceramic insulators. Progress is reported on the positive-ion injector upgrade for ATLAS. Also reported are building modifications and possible new uses for the tandem injector

  9. Accelerator simulation using computers

    International Nuclear Information System (INIS)

    Lee, M.; Zambre, Y.; Corbett, W.

    1992-01-01

    Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a ''multi-track'' simulation and analysis code can be used for these applications

  10. Modulational effects in accelerators

    International Nuclear Information System (INIS)

    Satogata, T.

    1997-01-01

    We discuss effects of field modulations in accelerators, specifically those that can be used for operational beam diagnostics and beam halo control. In transverse beam dynamics, combined effects of nonlinear resonances and tune modulations influence diffusion rates with applied tune modulation has been demonstrated. In the longitudinal domain, applied RF phase and voltage modulations provide mechanisms for parasitic halo transport, useful in slow crystal extraction. Experimental experiences with transverse tune and RF modulations are also discussed

  11. Neutrino physics and accelerators

    International Nuclear Information System (INIS)

    Kaftanov, V.

    1978-01-01

    The history is described of experiments aimed at the study of direct neutrino-matter interactions conducted in the past twenty years. Experiments are outlined carried out with the objective of proving the existence of the intermediate W meson which had been predicted by the weak interaction theory. The methods of obtaining neutrino beams using accelerators and the detectors used are briefly shown. Also described are experiments to be conducted in the near future in different laboratories. (Z.J.)

  12. Hadron beams and accelerators

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    There were four sessions on Hadron Beams and Accelerators with 7 talks on Siberian Snakes and spin rotators, 3 talks on polarization build-up of unpolarized beams in storage rings and 5, 9, and 3 talks on low, medium, and high energy polarimeters, respectively. In this paper I will briefly describe a few highlights from these sessions, giving emphasis to topics which I think will play an important role in the future. copyright 1995 American Institute of Physics

  13. Future Accelerator Magnet Needs

    International Nuclear Information System (INIS)

    Devred, Arnaud; Gourlay, Stephen A.; Yamamoto, Akira

    2005-01-01

    Superconducting magnet technology is continually evolving in order to meet the demanding needs of new accelerators and to provide necessary upgrades for existing machines. A variety of designs are now under development, including high fields and gradients, rapid cycling and novel coil configurations. This paper presents a summary of R and D programs in the EU, Japan and the USA. A performance comparison between NbTi and Nb 3 Sn along with fabrication and cost issues are also discussed

  14. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  15. Introduction to Accelerators Physics

    International Nuclear Information System (INIS)

    Variola, A.

    2007-01-01

    This short course aims at giving to high energy physics students a preliminary introduction to accelerators basics. The arguments and the style were selected in this perspective. Consequently, topics such as the definition of beam parameters and luminosity were preferred to much more technical aspects. The calculation details were neglected to allow more important highlights on concepts and definitions. Some examples and exercises were suggested to summarize the different topics of the lessons

  16. Operation of the accelerator

    International Nuclear Information System (INIS)

    GANIL Team

    1992-01-01

    The operation of the GANIL accelerator during 1991 and the first half of 1992 is reported. Results obtained with new beams, metallic beams and the first tests with the new injector system using an ECR source installed on a 100 kV platform are also given. Statistics of operation and beam characteristics are presented. The computer control system is also discussed. (K.A.) 7 refs.; 3 figs.; 8 tabs

  17. Accelerating News Issue 3

    CERN Document Server

    Kahle, K; Tanguy, C; Wildner, E

    2012-01-01

    This summer saw CERN announce to a worldwide audience the discovery of a Higgs-like boson, so this issue takes a look at the machine behind the discovery, the LHC, as well as future plans for a possible Higgs factory in the form of LEP3. Looking ahead too are European strategies for particle physics and accelerator-based neutrino physics. In addition, taking stock of the work so far, HiLumi LHC and EuCARD showcase their latest results.

  18. Particle acceleration by pulsars

    International Nuclear Information System (INIS)

    Arons, Jonathan.

    1980-06-01

    The evidence that pulsars accelerate relativistic particles is reviewed, with emphasis on the γ-ray observations. The current state of knowledge of acceleration in strong waves is summarized, with emphasis on the inability of consistent theories to accelerate very high energy particles without converting too much energy into high energy photons. The state of viable models for pair creation by pulsars is summarized, with the conclusion that pulsars very likely lose rotational energy in winds instead of in superluminous strong waves. The relation of the pair creation models to γ-ray observations and to soft X-ray observations of pulsars is outlined, with the conclusion that energetically viable models may exist, but none have yet yielded useful agreement with the extant data. Some paths for overcoming present problems are discussed. The relation of the favored models to cosmic rays is discussed. It is pointed out that the pairs made by the models may have observable consequences for observation of positrons in the local cosmic ray flux and for observations of the 511 keV line from the interstellar medium. Another new point is that asymmetry of plasma supply from at least one of the models may qualitatively explain the gross asymmetry of the X-ray emission from the Crab nebula. It is also argued that acceleration of cosmic ray nuclei by pulsars, while energetically possible, can occur only at the boundary of the bubbles blown by the pulsars, if the cosmic ray composition is to be anything like that of the known source spectrum

  19. Basic accelerator optics

    CERN Document Server

    CERN. Geneva. Audiovisual Unit

    1985-01-01

    A complete derivation, from first principles, of the concepts and methods applied in linear accelerator and beamline optics will be presented. Particle motion and beam motion in systems composed of linear magnets, as well as weak and strong focusing and special insertions are treated in mathematically simple terms, and design examples for magnets and systems are given. This series of five lectures is intended to provide all the basic tools required for the design and operation of beam optical systems.

  20. Superconducting magnets for accelerators

    International Nuclear Information System (INIS)

    Denisov, Yu.N.

    1979-01-01

    Expediency of usage and possibilities arising in application of superconducting devices in magnetic systems of accelerators and experimental nuclear-physical devices are studied. Parameters of specific devices are given. It is emphasized that at the existing level of technological possibilities, construction and usage of superconducting magnetic systems in experimental nuclear physics should be thought of as possible, from the engineering, and expedient, from the economical viewpoints [ru

  1. Linear induction accelerator

    Science.gov (United States)

    Buttram, M.T.; Ginn, J.W.

    1988-06-21

    A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

  2. Move of ground water

    International Nuclear Information System (INIS)

    Kimura, Shigehiko

    1983-01-01

    As a ground water flow which is difficult to explain by Darcy's theory, there is stagnant water in strata, which moves by pumping and leads to land subsidence. This is now a major problem in Japan. Such move on an extensive scale has been investigated in detail by means of 3 H such as from rainfall in addition to ordinary measurement. The move of ground water is divided broadly into that in an unsaturated stratum from ground surface to water-table and that in a saturated stratum below the water-table. The course of the analyses made so far by 3 H contained in water, and the future trend of its usage are described. A flow model of regarding water as plastic fluid and its flow as channel assembly may be available for some flow mechanism which is not possible to explain with Darcy's theory. (Mori, K.)

  3. Ground motion predictions

    Energy Technology Data Exchange (ETDEWEB)

    Loux, P C [Environmental Research Corporation, Alexandria, VA (United States)

    1969-07-01

    Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)

  4. Ground motion predictions

    International Nuclear Information System (INIS)

    Loux, P.C.

    1969-01-01

    Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)

  5. Laser-driven electron accelerators

    International Nuclear Information System (INIS)

    Palmer, R.B.

    1981-01-01

    The following possibilities are discussed: inverse free electron laser (wiggler accelerator); inverse Cerenkov effect; plasma accelerator; dielectric tube; and grating linac. Of these, the grating acceleraton is considered the most attractive alternative

  6. Optimizing accelerator technology

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    A new EU-funded research and training network, oPAC, is bringing together 22 universities, research centres and industry partners to optimize particle accelerator technology. CERN is one of the network’s main partners and will host 5 early-stage researchers in the BE department.   A diamond detector that will be used for novel beam diagnostics applications in the oPAC project based at CIVIDEC. (Image courtesy of CIVIDEC.) As one of the largest Marie Curie Initial Training Networks ever funded by the EU – to the tune of €6 million – oPAC extends well beyond the particle physics community. “Accelerator physics has become integral to research in almost every scientific discipline – be it biology and life science, medicine, geology and material science, or fundamental physics,” explains Carsten P. Welsch, oPAC co-ordinator based at the University of Liverpool. “By optimizing the operation of accelerators, all of these...

  7. Equipartitioning in linear accelerators

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1982-01-01

    Emittance growth has long been a concern in linear accelerators, as has the idea that some kind of energy balance, or equipartitioning, between the degrees of freedom, would ameliorate the growth. M. Prome observed that the average transverse and longitudinal velocity spreads tend to equalize as current in the channel is increased, while the sum of the energy in the system stays nearly constant. However, only recently have we shown that an equipartitioning requirement on a bunched injected beam can indeed produce remarkably small emittance growth. The simple set of equations leading to this condition are outlined. At the same time, Hofmann has investigated collective instabilities in transported beams and has identified thresholds and regions in parameter space where instabilities occur. Evidence is presented that shows transport system boundaries to be quite accurate in computer simulations of accelerating systems. Discussed are preliminary results of efforts to design accelerators that avoid parameter regions where emittance is affected by the instabilities identified by Hofmann. These efforts suggest that other mechanisms are present. The complicated behavior of the RFQ linac in this framework also is shown

  8. Equipartitioning in linear accelerators

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1981-01-01

    Emittance growth has long been a concern in linear accelerators, as has the idea that some kind of energy balance, or equipartitioning, between the degrees of freedom, would ameliorate the growth. M. Prome observed that the average transverse and longitudinal velocity spreads tend to equalize as current in the channel is increased, while the sum of the energy in the system stays nearly constant. However, only recently have we shown that an equipartitioning requirement on a bunched injected beam can indeed produce remarkably small emittance growth. The simple set of equations leading to this condition are outlined below. At the same time, Hofmann, using powerful analytical and computational methods, has investigated collective instabilities in transported beams and has identified thresholds and regions in parameter space where instabilities occur. This is an important generalization. Work that he will present at this conference shows that the results are essentially the same in r-z coordinates for transport systems, and evidence is presented that shows transport system boundaries to be quite accurate in computer simulations of accelerating systems also. Discussed are preliminary results of efforts to design accelerators that avoid parameter regions where emittance is affected by the instabilities identified by Hofmann. These efforts suggest that other mechanisms are present. The complicated behavior of the RFQ linac in this framework also is shown

  9. Laser driven particle acceleration

    International Nuclear Information System (INIS)

    Faure, J.

    2009-06-01

    This dissertation summarizes the last ten years of research at the Laboratory of Applied Optics on laser-plasma based electron acceleration. The main result consists of the development and study of a relativistic electron source with unique properties: high energy (100-300 MeV) in short distances (few millimeters), mono-energetic, ultra-short (few fs), stable and tunable. The manuscript describes the steps that led to understanding the physics, and then mastering it in order to produce this new electron source. Non linear propagation of the laser pulse in the plasma is first presented, with phenomena such as non linear wakefield excitation, relativistic and ponderomotive self-focusing in the short pulse regime, self-compression. Acceleration and injection of electrons are then reviewed from a theoretical perspective. Experimental demonstrations of self-injection in the bubble regime and then colliding pulse injection are then presented. These experiments were among the first to produce monoenergetic, high quality, stable and tunable electron beams from a laser-plasma accelerator. The last two chapters are dedicated to the characterization of the electron beam using transition radiation and to its applications to gamma radiography and radiotherapy. Finally, the perspectives of this research are presented in the conclusion. Scaling laws are used to determine the parameters that the electron beams will reach using peta-watt laser systems currently under construction. (author)

  10. SSC accelerator physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    Accelerator physicists at LBL began intensive work on the SSC in 1983, in support of the proposed 6.5-T magnet design, which, in turn, became reference design A during the Reference Designs Study. In that same study, LBL physicists formed the core of the accelerator physics group led by Fermilab's Don Edwards. In a period of only a few months, that group established preliminary parameters for a near-optimal design, produced conceptual designs based on three magnet types, addressed all significant beam lifetime and stability issues, and identified areas requiring further R and D. Since the conclusion of the Reference Designs Study, work has focused on the key SSC design issue, namely, single-particle stability in an imperfect magnetic field. At the end of fiscal 1984, much of the LBL accelerator physics group took its place in the SSC Central Design Group, whose headquarters at LBL will be the focus of nationwide SSC R and D efforts over the next several years

  11. The tandem betatron accelerator

    International Nuclear Information System (INIS)

    Keinigs, R.

    1991-01-01

    This paper reports that the tandem betatron is a compact, high-current induction accelerator that has the capability to accelerate electrons to an energy of order one gigavolt. Based upon the operating principle of a conventional betatron, the tandem betatron employs two synchronized induction cores operating 180 degrees out of phase. Embedded within the cores are the vacuum chambers, and these are connected by linear transport sections to allow for moving the beam back and forth between the two betatrons. The 180 degree phase shift between the core fluxes permits the circumvention of the flux swing constraint that limits the maximum energy gain of a conventional betatron. By transporting the beam between the synchronized cores, an electron can access more than one acceleration cycle, and thereby continue to gain energy. This added degree of freedom also permits a significant decrease in the size of the magnet system. Biasing coils provide independent control of the confining magnetic field. Provided that efficient beam switching can be performed, it appears feasible that a one gigavolt electron beam can be generated and confined. At this energy, a high current electron beam circulating in a one meter radius orbit could provide a very intense source of short wavelength (λ < 10 nm) synchrotron radiation. This has direct application to the emerging field of x-ray lithography. At more modest energies (10 MeV-30 MEV) a compact tandem betatron could be employed in the fields of medical radiation therapy, industrial radiography, and materials processing

  12. Turbulence and particle acceleration

    International Nuclear Information System (INIS)

    Scott, J.S.

    1975-01-01

    A model for the production of high energy particles in the supernova remnant Cas A is considered. The ordered expansion of the fast moving knots produce turbulent cells in the ambient interstellar medium. The turbulent cells act as magnetic scattering centers and charged particles are accelerated to large energies by the second order Fermi mechanism. Model predictions are shown to be consistent with the observed shape and time dependence of the radio spectrum, and with the scale size of magnetic field irregularities. Assuming a galactic supernova rate at 1/50 yr -1 , this mechanism is capable of producing the observed galactic cosmic ray flux and spectrum below 10 16 eV/nucleon. Several observed features of galactic cosmic rays are shown to be consistent with model predictions. A model for the objects known as radio tall galaxies is also presented. Independent blobs of magnetized plasma emerging from an active radio galaxy into an intracluster medium become turbulent due to Rayleigh--Taylor and Kelvin--Helmholz instabilities. The turbulence produces both in situ betatron and 2nd order Fermi accelerations. Predictions of the dependence of spectral index and flux on distance along the tail match observations well. Fitting provides values of physical parameters in the blobs. The relevance of this method of particle acceleration for the problem of the origin of x-ray emission in clusters of galaxies is discussed

  13. Accelerator mass spectrometry.

    Science.gov (United States)

    Hellborg, Ragnar; Skog, Göran

    2008-01-01

    In this overview the technique of accelerator mass spectrometry (AMS) and its use are described. AMS is a highly sensitive method of counting atoms. It is used to detect very low concentrations of natural isotopic abundances (typically in the range between 10(-12) and 10(-16)) of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg and even sub-mg size) and shorter measuring times (less than 1 hr). The equipment used for AMS is almost exclusively based on the electrostatic tandem accelerator, although some of the newest systems are based on a slightly different principle. Dedicated accelerators as well as older "nuclear physics machines" can be found in the 80 or so AMS laboratories in existence today. The most widely used isotope studied with AMS is 14C. Besides radiocarbon dating this isotope is used in climate studies, biomedicine applications and many other fields. More than 100,000 14C samples are measured per year. Other isotopes studied include 10Be, 26Al, 36Cl, 41Ca, 59Ni, 129I, U, and Pu. Although these measurements are important, the number of samples of these other isotopes measured each year is estimated to be less than 10% of the number of 14C samples. Copyright 2008 Wiley Periodicals, Inc.

  14. Particle Accelerator Focus Automation

    Science.gov (United States)

    Lopes, José; Rocha, Jorge; Redondo, Luís; Cruz, João

    2017-08-01

    The Laboratório de Aceleradores e Tecnologias de Radiação (LATR) at the Campus Tecnológico e Nuclear, of Instituto Superior Técnico (IST) has a horizontal electrostatic particle accelerator based on the Van de Graaff machine which is used for research in the area of material characterization. This machine produces alfa (He+) and proton (H+) beams of some μA currents up to 2 MeV/q energies. Beam focusing is obtained using a cylindrical lens of the Einzel type, assembled near the high voltage terminal. This paper describes the developed system that automatically focuses the ion beam, using a personal computer running the LabVIEW software, a multifunction input/output board and signal conditioning circuits. The focusing procedure consists of a scanning method to find the lens bias voltage which maximizes the beam current measured on a beam stopper target, which is used as feedback for the scanning cycle. This system, as part of a wider start up and shut down automation system built for this particle accelerator, brings great advantages to the operation of the accelerator by turning it faster and easier to operate, requiring less human presence, and adding the possibility of total remote control in safe conditions.

  15. Electrostatic Plasma Accelerator (EPA)

    Science.gov (United States)

    Brophy, John R.; Aston, Graeme

    1995-01-01

    The application of electric propulsion to communications satellites, however, has been limited to the use of hydrazine thrusters with electric heaters for thrust and specific impulse augmentation. These electrothermal thrusters operate at specific impulse levels of approximately 300 s with heater powers of about 500 W. Low power arcjets (1-3 kW) are currently being investigated as a way to increase specific impulse levels to approximately 500 s. Ion propulsion systems can easily produce specific impulses of 3000 s or greater, but have yet to be applied to communications satellites. The reasons most often given for not using ion propulsion systems are their high level of overall complexity, low thrust with long burn times, and the difficulty of integrating the propulsion system into existing commercial spacecraft busses. The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass.

  16. Particle Accelerator Focus Automation

    Directory of Open Access Journals (Sweden)

    Lopes José

    2017-08-01

    Full Text Available The Laboratório de Aceleradores e Tecnologias de Radiação (LATR at the Campus Tecnológico e Nuclear, of Instituto Superior Técnico (IST has a horizontal electrostatic particle accelerator based on the Van de Graaff machine which is used for research in the area of material characterization. This machine produces alfa (He+ and proton (H+ beams of some μA currents up to 2 MeV/q energies. Beam focusing is obtained using a cylindrical lens of the Einzel type, assembled near the high voltage terminal. This paper describes the developed system that automatically focuses the ion beam, using a personal computer running the LabVIEW software, a multifunction input/output board and signal conditioning circuits. The focusing procedure consists of a scanning method to find the lens bias voltage which maximizes the beam current measured on a beam stopper target, which is used as feedback for the scanning cycle. This system, as part of a wider start up and shut down automation system built for this particle accelerator, brings great advantages to the operation of the accelerator by turning it faster and easier to operate, requiring less human presence, and adding the possibility of total remote control in safe conditions.

  17. Accelerated Profile HMM Searches.

    Directory of Open Access Journals (Sweden)

    Sean R Eddy

    2011-10-01

    Full Text Available Profile hidden Markov models (profile HMMs and probabilistic inference methods have made important contributions to the theory of sequence database homology search. However, practical use of profile HMM methods has been hindered by the computational expense of existing software implementations. Here I describe an acceleration heuristic for profile HMMs, the "multiple segment Viterbi" (MSV algorithm. The MSV algorithm computes an optimal sum of multiple ungapped local alignment segments using a striped vector-parallel approach previously described for fast Smith/Waterman alignment. MSV scores follow the same statistical distribution as gapped optimal local alignment scores, allowing rapid evaluation of significance of an MSV score and thus facilitating its use as a heuristic filter. I also describe a 20-fold acceleration of the standard profile HMM Forward/Backward algorithms using a method I call "sparse rescaling". These methods are assembled in a pipeline in which high-scoring MSV hits are passed on for reanalysis with the full HMM Forward/Backward algorithm. This accelerated pipeline is implemented in the freely available HMMER3 software package. Performance benchmarks show that the use of the heuristic MSV filter sacrifices negligible sensitivity compared to unaccelerated profile HMM searches. HMMER3 is substantially more sensitive and 100- to 1000-fold faster than HMMER2. HMMER3 is now about as fast as BLAST for protein searches.

  18. Collective focusing ion accelerator

    International Nuclear Information System (INIS)

    Goldin, F.J.

    1986-01-01

    The principal subject of this dissertation is the trapping confinement of pure electron plasmas in bumpy toroidal magnetic fields, with particular attention given to the trapping procedure and the behavior of the plasma during the final equilibrium. The most important aspects of the equilibrium studied were the qualitative nature of the plasma configuration and motion and its density, distribution and stability. The motivation for this study was that an unneutralized cloud of electrons contained in a toroidal system, sufficiently dense and stable, may serve to electrostatically focus ions (against centrifugal and self space charge forces) in a cyclic ion accelerator. Such an accelerator, known as a Collective Focusing Ion Accelerator (CFIA) could be far smaller than conventional designs (which use external magnetic fields directly to focus the ions) due to the smaller gyro-radium of an electron in a magnetic field of given strength. The electron cloud generally drifted poloidally at a finite radius from the toroidal minor axis. As this would preclude focusing ions with such clouds, damping this motion was investigated. Finite resistance in the normally perfectly conductive vessel wall did this. In further preparation for a working CFIA, additional experiments studied the effect of ions on the stability of the electron cloud

  19. Berkeley Proton Linear Accelerator

    Science.gov (United States)

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  20. Heavy ion accelerating structure

    International Nuclear Information System (INIS)

    Pottier, Jacques.

    1977-01-01

    The heavy ion accelerating structure concerned in this invention is of the kind that have a resonance cavity inside which are located at least two longitudinal conducting supports electrically connected to the cavity by one of their ends in such a way that they are in quarter-wavelength resonance and in phase opposition. Slide tubes are electrically connected alternatively to one or the other of the two supports, they being electrically connected respectively to one or the other end of the side wall of the cavity. The feature of the structure is that it includes two pairs of supports symmetrically placed with respect to the centre line of the cavity, the supports of one pair fitted overhanging being placed symmetrically with respect to the centre line of the cavity, each slide tube being connected to the two supports of one pair. These support are connected to the slide wall of the cavity by an insulator located at their electrically free end. The accelerator structure composed of several structures placed end to end, the last one of which is fed by a high frequency field of adjustable amplitude and phase, enables a heavy ion linear accelerator to be built [fr