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1

A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov Fermi National Accelerator Laboratory June 2012  

E-print Network

are operated and monitored from Fermilab's Main Control Room. Tevatron experiments pioneered the use of silicon pioneered new radio-frequency manipulation techniques and developed the first electron-cooling system research program yielded transformational achievements in accelerator, detector and computing technology

Quigg, Chris

2

Lattice parameters database and operational simulation at FNAL and SSCL  

Microsoft Academic Search

A collaboration has been formed at FNAL (Fermi National Accelerator Laboratory) and SSCL (Superconducting Super Collider Laboratory) to develop software tools for operational simulation of existing and planned accelerator systems. The toolset is organized around an accelerator lattice description maintained by a commercial database management system. The tools presently available for public use are described

Eric Barr; S. Peggs; L. Michelotti; A. Russell; S. Saritepe; C. G. Trahern; J. Zhou

1991-01-01

3

FNAL-NICADD extruded scintillator  

SciTech Connect

The possibility to produce a scintillator that satisfies the demands of physicists from different science areas has emerged with the installation of an extrusion line at Fermi National Accelerator Laboratory (FNAL). The extruder is the product of the fruitful collaboration between FNAL and Northern Illinois Center for Accelerator and Detector Development (NICADD) at Northern Illinois University (NIU). The results from the light output, light attenuation length and mechanical tolerance indicate that FNAL-NICADD scintillator is of high quality. Improvements in the extrusion die will yield better scintillator profiles and decrease the time needed for initial tuning. This paper will present the characteristics of the FNAL-NICADD scintillator based on the measurements performed. They include the response to MIPs from cosmic rays for individual extruded strips and irradiation studies where extruded samples were irradiated up to 1 Mrad. We will also discuss the results achieved with a new die design. The attractive perspective of using the extruded scintillator with MRS (Metal Resistive Semiconductor) photodetector readout will also be shown.

Beznosko, D.; /Northern Illinois U.; Bross, A.; /Fermilab; Dyshkant, A.; /Northern Illinois U.; Pla-Dalmau, A.; /Fermilab; Rykalin, V.; /Northern Illinois U.

2005-09-01

4

Parameter degeneracies in FNAL-Homestake LBNE setup  

E-print Network

LBNE (Longbaseline Neutrino Oscillation Experiments) provide a powerful experimental setup to study sensitivities and exlcusion limits in neutrino oscillation parameter space. A longbaseline experiment is being planned, at USA, from FNAL (Fermilab National Accelerator Laboratory) to an underground laboratory at Homestake in South Dakota, at an angle of 5.84 degrees from FNAL (at a distance of 1289 km). The prospect of a new beamline towards this location from FNAL, and a 300 Kiloton water Cerenkov detector at the site is in planning stage, for the studies of the neutrino physics program. The long baseline provides sufficient matter effects for neutrino travel, and a large detrecor will help towards better statistics. In this work, we present, upto what extent, the parameter degeneracies, present in oscillation parameter space, can be resolved, using this FNAL-LBNE setup.

Bora, Kalpana

2011-01-01

5

Parameter degeneracies in FNAL-Homestake LBNE setup  

E-print Network

LBNE (Longbaseline Neutrino Oscillation Experiments) provide a powerful experimental setup to study sensitivities and exlcusion limits in neutrino oscillation parameter space. A longbaseline experiment is being planned, at USA, from FNAL (Fermilab National Accelerator Laboratory) to an underground laboratory at Homestake in South Dakota, at an angle of 5.84 degrees from FNAL (at a distance of 1289 km). The prospect of a new beamline towards this location from FNAL, and a 300 Kiloton water Cerenkov detector at the site is in planning stage, for the studies of the neutrino physics program. The long baseline provides sufficient matter effects for neutrino travel, and a large detrecor will help towards better statistics. In this work, we present, upto what extent, the parameter degeneracies, present in oscillation parameter space, can be resolved, using this FNAL-LBNE setup.

Kalpana Bora

2011-11-30

6

Vehicle Systems Integration Laboratory Accelerates Powertrain Development  

SciTech Connect

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

None

2014-04-15

7

Numerical and laboratory simulations of auroral acceleration  

SciTech Connect

The existence of parallel electric fields is an essential ingredient of auroral physics, leading to the acceleration of particles that give rise to the auroral displays. An auroral flux tube is modelled using electrostatic Vlasov simulations, and the results are compared to simulations of a proposed laboratory device that is meant for studies of the plasma physical processes that occur on auroral field lines. The hot magnetospheric plasma is represented by a gas discharge plasma source in the laboratory device, and the cold plasma mimicking the ionospheric plasma is generated by a Q-machine source. In both systems, double layers form with plasma density gradients concentrated on their high potential sides. The systems differ regarding the properties of ion acoustic waves that are heavily damped in the magnetosphere, where the ion population is hot, but weakly damped in the laboratory, where the discharge ions are cold. Ion waves are excited by the ion beam that is created by acceleration in the double layer in both systems. The efficiency of this beam-plasma interaction depends on the acceleration voltage. For voltages where the interaction is less efficient, the laboratory experiment is more space-like.

Gunell, H.; De Keyser, J. [1Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels (Belgium)] [1Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels (Belgium); Mann, I. [EISCAT Scientific Association, P.O. Box 812, SE-981 28 Kiruna, Sweden and Department of Physics, Umeå University, SE-901 87 Umeå (Sweden)] [EISCAT Scientific Association, P.O. Box 812, SE-981 28 Kiruna, Sweden and Department of Physics, Umeå University, SE-901 87 Umeå (Sweden)

2013-10-15

8

Numerical and laboratory simulations of auroral acceleration  

NASA Astrophysics Data System (ADS)

The existence of parallel electric fields is an essential ingredient of auroral physics, leading to the acceleration of particles that give rise to the auroral displays. An auroral flux tube is modelled using electrostatic Vlasov simulations, and the results are compared to simulations of a proposed laboratory device that is meant for studies of the plasma physical processes that occur on auroral field lines. The hot magnetospheric plasma is represented by a gas discharge plasma source in the laboratory device, and the cold plasma mimicking the ionospheric plasma is generated by a Q-machine source. In both systems, double layers form with plasma density gradients concentrated on their high potential sides. The systems differ regarding the properties of ion acoustic waves that are heavily damped in the magnetosphere, where the ion population is hot, but weakly damped in the laboratory, where the discharge ions are cold. Ion waves are excited by the ion beam that is created by acceleration in the double layer in both systems. The efficiency of this beam-plasma interaction depends on the acceleration voltage. For voltages where the interaction is less efficient, the laboratory experiment is more space-like.

Gunell, H.; De Keyser, J.; Mann, I.

2013-10-01

9

US accelerator contribution to the LHC  

SciTech Connect

In 1998, the United States entered into an agreement with CERN to help build the Large Hadron Collider (LHC), with contributions to the accelerator and to the large HEP detectors. To accomplish this, the US LHC Accelerator Project was formed, encompassing expertise from Brookhaven National Laboratory (BNL), Fermi National Accelerator Laboratory (FNAL) and the Lawrence Berkeley National Laboratory (LBNL). This report is a summary of these contributions including the progress towards project completion, as well as a discussion of future plans for continued US participation in the LHC accelerator.

Lamm, Michael J.; /Fermilab

2005-05-01

10

Muon g-2 Experiment A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov  

E-print Network

Muon g-2 Experiment A national laboratory funded by the Office of Science of the Department know. The experiment Muon g-2 (pronounced gee-minus-two) is an international collaboration between U that lives for about two microseconds, in greater detail than ever before. The Muon g-2 experiment will study

Quigg, Chris

11

A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov Fermi National Accelerator Laboratory March 2013  

E-print Network

includes approximately 282 species of birds, 56 species of butterflies,10 species of frogs and endangered. Several rare species of birds and butterflies call the site home for portions of the year. Every year migration patterns and species health. Fermilab annually monitors the health of plants, butterflies, frogs

Quigg, Chris

12

The target laboratory of the Pelletron Accelerator's facilities  

SciTech Connect

A short report on the activities developed in the Target Laboratory, since 1970, will be presented. Basic target laboratory facilities were provided to produce the necessary nuclear targets as well as the ion beam stripper foils. Vacuum evaporation units, a roller, a press and an analytical balance were installed in the Oscar Sala building. A brief historical report will be presented in commemoration of the 40{sup th} year of the Pelletron Accelerator.

Ueta, Nobuko; Pereira Engel, Wanda Gabriel [Nuclear Physics Department - University of Sao Paulo (Brazil)

2013-05-06

13

Reproduction of natural corrosion by accelerated laboratory testing methods  

SciTech Connect

Various laboratory corrosion tests have been developed to study the behavior of glass waste forms under conditions similar to those expected in an engineered repository. The data generated by laboratory experiments are useful for understanding corrosion mechanisms and for developing chemical models to predict the long-term behavior of glass. However, it is challenging to demonstrate that these test methods produce results that can be directly related to projecting the behavior of glass waste forms over time periods of thousands of years. One method to build confidence in the applicability of the test methods is to study the natural processes that have been taking place over very long periods in environments similar to those of the repository. In this paper, we discuss whether accelerated testing methods alter the fundamental mechanisms of glass corrosion by comparing the alteration patterns that occur in naturally altered glasses with those that occur in accelerated laboratory environments. This comparison is done by (1) describing the alteration of glasses reacted in nature over long periods of time and in accelerated laboratory environments and (2) establishing the reaction kinetics of naturally altered glass and laboratory reacted glass waste forms.

Luo, J.S.; Wronkiewicz, D.J.; Mazer, J.J.; Bates, J.K.

1996-05-01

14

Modeling laser-plasma acceleration in the laboratory frame  

SciTech Connect

A simulation of laser-plasma acceleration in the laboratory frame. Both the laser and the wakefield buckets must be resolved over the entire domain of the plasma, requiring many cells and many time steps. While researchers often use a simulation window that moves with the pulse, this reduces only the multitude of cells, not the multitude of time steps. For an artistic impression of how to solve the simulation by using the boosted-frame method, watch the video "Modeling laser-plasma acceleration in the wakefield frame."

None

2011-01-01

15

Brookhaven National Laboratory's Accelerator Test Facility: research highlights and plans  

NASA Astrophysics Data System (ADS)

The Accelerator Test Facility (ATF) at Brookhaven National Laboratory has served as a user facility for accelerator science for over a quarter of a century. In fulfilling this mission, the ATF offers the unique combination of a high-brightness 80 MeV electron beam that is synchronized to a 1 TW picosecond CO2 laser. We unveil herein our plan to considerably expand the ATF's floor space with an upgrade of the electron beam's energy to 300 MeV and the CO2 laser's peak power to 100 TW. This upgrade will propel the ATF even further to the forefront of research on advanced accelerators and radiation sources, supporting the most innovative ideas in this field. We discuss emerging opportunities for scientific breakthroughs, including the following: plasma wakefield acceleration studies in research directions already active at the ATF; laser wakefield acceleration (LWFA), where the longer laser wavelengths are expected to engender a proportional increase in the beam's charge while our linac will assure, for the first time, the opportunity to undertake detailed studies of seeding and staging of the LWFA; proton acceleration to the 100-200 MeV level, which is essential for medical applications; and others.

Pogorelsky, I. V.; Ben-Zvi, I.

2014-08-01

16

Low Energy Accelerator Laboratory Technical Area 53, Los Alamos National Laboratory. Environmental assessment  

SciTech Connect

This Environmental Assessment (EA) analyzes the potential environmental impacts that would be expected to occur if the Department of Energy (DOE) were to construct and operate a small research and development laboratory building at Technical Area (TA) 53 at the Los Alamos National Laboratory (LANL), Los Alamos, New Mexico. DOE proposes to construct a small building to be called the Low Energy Accelerator Laboratory (LEAL), at a previously cleared, bladed, and leveled quarter-acre site next to other facilities housing linear accelerator research activities at TA-53. Operations proposed for LEAL would consist of bench-scale research, development, and testing of the initial section of linear particle accelerators. This initial section consists of various components that are collectively called an injector system. The anticipated life span of the proposed development program would be about 15 years.

NONE

1995-04-01

17

Absolute gravity acceleration measurement in atomic sensor laboratories  

NASA Astrophysics Data System (ADS)

This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the Florence University (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the measurement of forces with high spatial resolution are in progress. Both experiments require an independent knowledge on the local value of g. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are ( 980 492 160.6 ± 4.0) ?Gal and ( 980 492 048.3 ± 3.0) ?Gal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

2012-03-01

18

Post-accelerator issues at the IsoSpin Laboratory  

SciTech Connect

The workshop on ``Post-Accelerator Issues at the Isospin Laboratory`` was held at the Lawrence Berkeley Laboratory from October 27--29, 1993. It was sponsored by the Center for Beam Physics in the Accelerator and Fusion Research Division and the ISL Studies Group in the Nuclear Science Division. About forty scientists from around the world participated vigorously in this two and a half day workshop, (c.f. Agenda, Appendix D). Following various invited review talks from leading practitioners in the field on the first day, the workshop focussed around two working groups: (1) the Ion Source and Separators working group and (2) the Radio Frequency Quadrupoles and Linacs working group. The workshop closed with the two working groups summarizing and outlining the tasks for the future. This report documents the proceedings of the workshop and includes the invited review talks, the two summary talks from the working groups and individual contributions from the participants. It is a complete assemblage of state-of-the-art thinking on ion sources, low-{beta}, low(q/A) accelerating structures, e.g. linacs and RFQS, isobar separators, phase-space matching, cyclotrons, etc., as relevant to radioactive beam facilities and the IsoSpin Laboratory. We regret to say that while the fascinating topic of superconducting low-velocity accelerator structure was covered by Dr. K. Shepard during the workshop, we can only reproduce the copies of the transparencies of his talk in the Appendix, since no written manuscript was available at the time of publication of this report. The individual report have been catologed separately elsewhere.

Chattopadhyay, S.; Nitschke, J.M. [eds.

1994-05-01

19

Accelerated weathering of cementitious matrix for the development of an accelerated laboratory test of biodeterioration  

Microsoft Academic Search

Cement based materials are porous, may contain organic adjuvants, and thus possesses an important primary bioreceptivity.\\u000a To preserve constructions from fungal colonization and to act efficiently against fungal biodeterioration, it is necessary\\u000a to have a better understanding of biodeterioration mechanisms and its effects on materials properties. An accelerated laboratory\\u000a test which allows us to compare the growth of three fungal

Virginie Wiktor; Philippe Grosseau; René Guyonnet; Eric Garcia-Diaz; Christine Lors

2011-01-01

20

The cyclotron laboratory and the RFQ accelerator in Bern  

SciTech Connect

Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Weber, M. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Scampoli, P. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland and Department of Physical Sciences, University Federico II, Via Cintia, I-60126 Napoli (Italy); Bremen, K. von [SWAN Isotopen AG, Inselspital, CH-3010 Bern (Switzerland)

2013-07-18

21

The cyclotron laboratory and the RFQ accelerator in Bern  

NASA Astrophysics Data System (ADS)

Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Scampoli, P.; von Bremen, K.; Weber, M.

2013-07-01

22

PREFACE: Acceleration and radiation generation in space and laboratory plasmas  

NASA Astrophysics Data System (ADS)

Sixty-six leading researchers from ten nations gathered in the Homeric village of Kardamyli, on the southern coast of mainland Greece, from August 29-September 4, 1993 for the International Workshop on Acceleration and Radiation Generation in Space and Laboratory Plasmas. This Special Issue represents a cross-section of the presentations made at and the research stimulated by that meeting. According to the Iliad, King Agamemnon used Kardamyli as a dowry offering in order to draw a sulking Achilles into the Trojan War. 3000 years later, Kardamyli is no less seductive. Its remoteness and tranquility made it an ideal venue for promoting the free exchange of ideas between various disciplines that do not normally interact. Through invited presen tations, informal poster discussions and working group sessions, the Workshop brought together leaders from the laboratory and space/astrophysics communities working on common problems of acceleration and radiation generation in plasmas. It was clear from the presentation and discussion sessions that there is a great deal of common ground between these disciplines which is not at first obvious due to the differing terminologies and types of observations available to each community. All of the papers in this Special Issue highlight the role collective plasma processes play in accelerating particles or generating radiation. Some are state-of-the-art presentations of the latest research in a single discipline, while others investi gate the applicability of known laboratory mechanisms to explain observations in natural plasmas. Notable among the latter are the papers by Marshall et al. on kHz radiation in the magnetosphere ; Barletta et al. on collective acceleration in solar flares; and by Dendy et al. on ion cyclotron emission. The papers in this Issue are organized as follows: In Section 1 are four general papers by Dawson, Galeev, Bingham et al. and Mon which serves as an introduction to the physical mechanisms of acceleration and radiation generation in plasmas. The next section includes state-of-the-art papers on laboratory accelerators driven by lasers (Nakajima et al., Shukla, Johnson et al.), microwaves (Nishida et al., Bogomolov et al.) and by particle beams (Ogata et al.). Also in this section are theoretical papers presenting new work on synchrotron like oscillations in plasma waves (Fedele) and two types of laboratory radiation sources, FEL's (Marshall et al.) and ionization fronts (Lai et al.), and Frantzeskakis et al. described the Hamiltonian analysis of a slow-wave autonomous cyclotron buncher. Section 3 contains papers on astrophysical plasmas, with the general presentations of Colgate and Krishnan. Kazanas and Krishnan address active galactic nuclei (AGNs). Thielheim discusses general acceleration mech anisms in rotating magnetized systems. Asseo discussed Langmuir solitons in pulsars and Blackman et al. treat magnetic reconnection relativistically. Su et al. analyze the possibility of plasma wave excitation and particle acceleration by neu trinos from supernovae. Dogiel et al. on cosmic ray scattering by MHD fluctuations. The papers in Section 4 treat fusion plasmas (Dendy et al. and Lashmore-Davies et al.). Section 5, space plasmas, includes papers on acceleration processes in the magnetosphere (Anagnostopoulos and Marshall et al.) and the sun (Barletta et al.). It is evident from the Workshop and the papers collected here that this is indeed a rich field of investigations and that both the natural and laboratory plasma communities can benefit from the cross-fertilization of ideas between them. We wish to thank the authors and attendees for their contributions to the success of this workshop, Dr Philip Debenham and Dr David Sutter of the U.S. D.o.E. and Dr Charles Roberson of the U.S. O.N.R. for their financial support (Grants DE-FGO3-93ER40776 and N00014-93-1-0814), and the ECC Twinning Grant SC1*-CT92-0773. We appreciate the considerable local support from Mr Glegles and his staff at the Agricultural Bank of Greece. We thank Mr V. Tataronis, mayor of Kardamyli, and

Bingham, R.; Katsouleas, T.; Dawson, J. M.; Stenflo, L.

1994-01-01

23

K.T. McDonald June 18, 2009 DUSEL Workshop @ FNAL 1 Strategies for Liquid Argon Detectors at DUSEL  

E-print Network

K.T. McDonald June 18, 2009 DUSEL Workshop @ FNAL 1 Strategies for Liquid Argon Detectors at DUSEL proposal is to build a 5 kton liquid argon detector for use at that time. However, that size is too small desire a giant liquid argon detector in its first round of accelerator neutrino physics. We should rise

McDonald, Kirk

24

Materials Dynamics Laboratory (RIKEN SPring-8 Center) Alfred Baron Mathematical Physics Laboratory (RIKEN Nishina Center for Accelerator-Based Science) Koji Hashimoto  

E-print Network

(RIKEN Nishina Center for Accelerator-Based Science) Koji Hashimoto Strangeness Nuclear Physics Nakagawa Theoretical Nuclear Physics Laboratory (RIKEN Nishina Center for Accelerator-Based ScienceMaterials Dynamics Laboratory (RIKEN SPring-8 Center) Alfred Baron Mathematical Physics Laboratory

Fukai, Tomoki

25

The scanning electron microscope as an accelerator for the undergraduate advanced physics laboratory  

E-print Network

Few universities or colleges have an accelerator for use with advanced physics laboratories, but many of these institutions have a scanning electron microscope (SEM) on site, often in the biology department. As an accelerator ...

Peterson, Randolph S.

26

Accelerator issues and challenges at the IsoSpin Laboratory  

SciTech Connect

The layout of an IsoSpin Laboratory as conceived presently and its current parametric specifications are shown, respectively. The generic features of such a facility are: large dynamic range (in energy, intensity, ion species (q/A), etc.), high intensity, high duty factor, required low beam emittances, high beam purity, operation under high radiation background (e.g., 60 kRad/hour at 1 meter from target) and almost zero tolerance for beam loss (required transmission efficiency of {approximately} 100%). This last feature demands almost perfect matching of beam phase space from the ion source into the post accelerator and from the post accelerator into the high energy linac, etc. The goals of the ISL are unquestionably ambitious and challenging, leaving aside the demanding issues of targetry and radiation shielding, which were not in the scope of this workshop. Nevertheless, through dedicated R&D effort and focussed workshops in the past including the present one, reasonably feasible technical solutions seem to be emerging so that the author is beginning to share an increasingly optimistic outlook on the realizability of the ISL in near future.

Chattopadhyay, S. [Lawrence Berkeley Lab., CA (United States)

1994-05-01

27

Tiger Team Assessment of the Fermi National Accelerator Laboratory  

SciTech Connect

This draft report documents the Tiger Team Assessment of the Fermi National Accelerator Laboratory (Fermilab) located in Batavia, Illinois. Fermilab is a program-dedicated national laboratory managed by the Universities Research Association, Inc. (URA) for the US Department of Energy (DOE). The Tiger Team Assessment was conducted from May 11 to June 8, 1992, under the auspices of DOE's Office of Special Projects (OSP) under the Office of the Assistant Secretary for Environment, Safety and Health (EH). The assessment was comprehensive, encompassing environmental, safety and health (ES H), and quality assurance (QA) disciplines; site remediation; facilities management; and waste management operations. Compliance with applicable Federal , State of Illinois, and local regulations; applicable DOE Orders; best management practices; and internal Fermilab requirements was addressed. In addition, an evaluation of the effectiveness of DOE and Fermilab management of the ES H/QA and self-assessment programs was conducted. The Fermilab Tiger Team Assessment is part a larger, comprehensive DOE Tiger Team Independent Assessment Program planned for DOE facilities. The objective of the initiative is to provide the Secretary of Energy with information on the compliance status of DOE facilities with regard to ES H requirements, root causes for noncompliance, adequacy of DOE and contractor ES H management programs, response actions to address the identified problem areas, and DOE-wide ES H compliance trends and root causes.

Not Available

1992-06-01

28

Tiger Team Assessment of the Fermi National Accelerator Laboratory  

SciTech Connect

This draft report documents the Tiger Team Assessment of the Fermi National Accelerator Laboratory (Fermilab) located in Batavia, Illinois. Fermilab is a program-dedicated national laboratory managed by the Universities Research Association, Inc. (URA) for the US Department of Energy (DOE). The Tiger Team Assessment was conducted from May 11 to June 8, 1992, under the auspices of DOE`s Office of Special Projects (OSP) under the Office of the Assistant Secretary for Environment, Safety and Health (EH). The assessment was comprehensive, encompassing environmental, safety and health (ES&H), and quality assurance (QA) disciplines; site remediation; facilities management; and waste management operations. Compliance with applicable Federal , State of Illinois, and local regulations; applicable DOE Orders; best management practices; and internal Fermilab requirements was addressed. In addition, an evaluation of the effectiveness of DOE and Fermilab management of the ES&H/QA and self-assessment programs was conducted. The Fermilab Tiger Team Assessment is part a larger, comprehensive DOE Tiger Team Independent Assessment Program planned for DOE facilities. The objective of the initiative is to provide the Secretary of Energy with information on the compliance status of DOE facilities with regard to ES&H requirements, root causes for noncompliance, adequacy of DOE and contractor ES&H management programs, response actions to address the identified problem areas, and DOE-wide ES&H compliance trends and root causes.

Not Available

1992-06-01

29

Plasma Astrophysics in the Laboratory with Accelerator Beams  

NASA Astrophysics Data System (ADS)

An ultra-relativistic electron/positron or ``fireball'' beam interacting with a laboratory plasma is subject to the current filamentation instability (CFI). In the near future, ultra-short (<100fs), ultra-relativistic (25GeV) electron and positron bunches will become available at the SLAC FACET facility. These bunches are accelerated one half period apart and overlapped in space and time near the final focal point. With an equal number of particles, these two bunches form a neutral, field- and charge-free beam that we call a relativistic fireball beam. The interaction of this beam with laboratory plasma is rather different from that of either the electron or positron bunch alone. No large wakefields are generated. Instead the beam is subject to the CFI, which results in transverse filamentation, accompanied by strong plasma density modulation, generation of large magnetic fields, and generation of radiation that can be detected. This situation is similar to that of space relativistic plasmas, e.g. from supernovae, interacting with the interstellar medium. The CFI generates the magnetic field, and the charged particles emit radiation as in gamma ray bursts afterglow. Detecting the CFI and measuring it characteristics will validate astrophysical models. CFI may also play an important role in the propagation of hot electrons in plasmas for example in the fast igniter concept of ICF. We describe the CFI and the experiment to detect it.

Muggli, P.; Martins, S.; Silva, L.

2010-11-01

30

Laboratory Test of Newton's Second Law for Small Accelerations  

SciTech Connect

We have tested the proportionality of force and acceleration in Newton's second law, F=ma, in the limit of small forces and accelerations. Our tests reach well below the acceleration scales relevant to understanding several current astrophysical puzzles such as the flatness of galactic rotation curves, the Pioneer anomaly, and the Hubble acceleration. We find good agreement with Newton's second law at accelerations as small as 5x10{sup -14} m/s{sup 2}.

Gundlach, J. H.; Schlamminger, S.; Spitzer, C. D.; Choi, K.-Y.; Woodahl, B. A.; Coy, J. J.; Fischbach, E. [Center for Experimental Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195 (United States); Physics Department, Indiana University-Purdue University, Indianapolis, Indiana 46202 (United States); Earth and Space Science Department, Saint Joseph's College, Rensselaer, Indiana 47978 (United States); Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States)

2007-04-13

31

Investigations of the output energy deviation and other parameters during commissioning of the four-rod radio frequency quadrupole at the Fermi National Accelerator Laboratory  

SciTech Connect

After 30 years of operation, the Cockcroft-Walton based injector at FNAL (Fermi National Accelerator Laboratory) has been replaced by a new beam line including a dimpled magnetron 35 keV source in combination with a 750 keV 4-rod Radio Frequency Quadrupole (RFQ). The new injector is followed by the existing drift tube linac (DTL). Prior to installation, a test beam line was built which included the magnetron source and the 4-rod RFQ with a number of beam measurement instrumentation. The first beam test with the RFQ showed an output energy deviation greater than 2.5%. Other problems also showed up which led to investigations of the output energy, power consumption and transmission properties using RF simulations which were complemented with additional beam measurements. The sources of this deviation and the mechanical modifications of the RFQ to solve this matter will be presented in this paper. Meanwhile, the nominal output energy of 750 keV has been confirmed and the new injector with the 4-rod RFQ is in full operation.

Schmidt, J.S.; et al.,

2014-03-01

32

PARTICLE ACCELERATION BY THE SUN ''Physics Department & Space Sciences Laboratory, University of California, Berkeley, CA  

E-print Network

PARTICLE ACCELERATION BY THE SUN R. P. Lin" ''Physics Department & Space Sciences Laboratory. INTRODUCTION The Sun is the most energetic particle accelerator in the solar system. In large solar flares energetic particle (SEP) events observed near 1 AU, but they, however, appear to be accelerated by shock

California at Berkeley, University of

33

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

SciTech Connect

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

Peterson, Randolph S. [Department of Physics and Astronomy, University of the South, 735 University Avenue, Sewanee TN 37383 (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 50 Vassar Street, Cambridge MA 01239 (United States); Berggren, Karl K.; Mondol, Mark [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 50 Vassar Street, Cambridge MA 01239 (United States)

2011-06-01

34

Laser Plasma Acceleration Experiment at the Naval Research Laboratory.  

NASA Astrophysics Data System (ADS)

The traditional long term strategy for producing high quality electron beams in a single stage LWFA involves three elements: operation in the resonant or standard regime, the use of optical guiding to extend the acceleration region, and external injection of a precisely-phased, high quality injection electron bunch. The standard regime and optical guiding has been studied by many research groups and promise good results for the acceleration. The creation of the electron beam for external injection is still a very problematic issue. Most experiments to date have operated in the self modulated (SM) regime, which produces very large accelerating gradients but poor quality electron beams with large energy spread. More recently, quasi-monoenergetic acceleration of particles from the background plasma has been observed in simulations and experiments operating in a shorter pulse regime. Such quasi-monoenergetic electrons could be a candidate for injection into a following stage of standard LWFA if not for the relatively poor shot to shot reproducibility. We are in the initial stage of experiments to generate injection electrons using the HD-LIPA schemes with a 10 TW 50 fs laser system. The second stage accelerator will be a capillary discharge plasma channel for extended acceleration distance. Preliminary results, including statistics on the stability of quasi-monoenergetic acceleration, will be presented. Supported by DOE and ONR.

Kaganovich, D.; Ting, A.; Gordon, D.; Hubbard, R.; Jones, T.; Zigler, A.; Sprangle, P.

2006-10-01

35

Parag Mhashilkar (Fermi National Accelerator Laboratory) Cathrin Weiss (Condor Project, University of Wisconsin at Madison)  

E-print Network

Parag Mhashilkar (Fermi National Accelerator Laboratory) Cathrin Weiss (Condor Project, University sandbox management Sandbox Management & Sandbox Manager Sandbox Transfer in Condor Current Protocol Asynchronous sandbox transfer Prototype & Its Performance Ongoing & Future Work Acknowledgements 2Condor

Liblit, Ben

36

Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasmaa)  

E-print Network

Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasmaa January 2014; accepted 20 February 2014; published online 7 May 2014) Bulk ion acceleration and particle Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from

Ji, Hantao

37

Observation of Ion Acceleration and Heating during Collisionless Magnetic Reconnection in a Laboratory Plasma  

SciTech Connect

The ion dynamics in a collisionless magnetic reconnection layer are studied in a laboratory plasma. The measured in-plane plasma potential profile, which is established by electrons accelerated around the electron diffusion region, shows a saddle-shaped structure that is wider and deeper towards the outflow direction. This potential structure ballistically accelerates ions near the separatrices toward the outflow direction. Ions are heated as they travel into the high pressure downstream region.

Jongsoo Yoo, Masaaki Yamada, HantaoJi and Clayton E. Myers

2012-12-10

38

FNAL E665 - a case study in portable computing  

SciTech Connect

The Fermilab Muon Scattering Experiment, E665, has used highly portable code to maximize CPU resources by moving to faster systems as soon as they become available. E665 has been able to take advantage of the FNAL UNIX Farms and CLUBS systems to reduce and analyze 1 TB of data without custom designed hardware.

Schellman, H. [Northwestern Univ., Evanston, IL (United States)

1994-12-31

39

ACCELERATION OF LOS ALAMOS NATIONAL LABORATORY TRANSURANIC WASTE DISPOSITION  

SciTech Connect

One of Los Alamos National Laboratory's (LANL's) most significant risks is the site's inventory of transuranic waste retrievably stored above and below-ground in Technical Area (TA) 54 Area G, particularly the dispersible high-activity waste stored above-ground in deteriorating facilities. The high activity waste represents approximately 50% (by activity) of the total 292,000 PE-Ci inventory remaining to be disposed. The transuramic waste inventory includes contact-handled and remote-handled waste packaged in drums, boxes, and oversized containers which are retrievably stored both above and below-ground. Although currently managed as transuranic waste, some of the inventory is low-level waste that can be disposed onsite or at approved offsite facilities. Dispositioning the transuranic waste inventory requires retrieval of the containers from above and below-ground storage, examination and repackaging or remediation as necessary, characterization, certification and loading for shipment to the Waste Isolation Pilot Plant in Carlsbad New Mexico, all in accordance with well-defined requirements and controls. Although operations are established to process and characterize the lower-activity contact-handled transuranic waste containers, LAN L does not currently have the capability to repack high activity contact-handled transuranic waste containers (> 56 PE-Ci) or to process oversized containers with activity levels over 0.52 PE-Ci. Operational issues and compliance requirements have resulted in less than optimal processing capabilities for lower activity contact-handled transuranic waste containers, limiting preparation and reducing dependability of shipments to the Waste Isolation Pilot Plant. Since becoming the Los Alamos National Laboratory contract in June 2006, Los Alamos National Security (LANS) L.L.C. has developed a comprehensive, integrated plan to effectively and efficiently disposition the transuranic waste inventory, working in concert with the Department of Energy Los Alamos Site Office, Carlsbad Field Office and the Department of Energy Headquaeters. Rather than simply processing containers as retrieved, the plan places priority on efficient curie disposition, a direct correlation to reducing risk. Key elements of the approch include balancing inventory and operational risks, tailoring methods to meet requirements, optimizing existing facilities, equipment and staff, and incorporating best practices from other Department of Energy sites. With sufficient funding this will enable LANL to ship the above-ground high activity contact-handled transuranic waste offsite by the end of Fiscal Year (FY) 2007 and to disposition the remaining above- and below-ground contact-handled and remote-handled transuranic waste inventory by December 2010. Nearly 70% of the contact-handled transuranic waste containers, including the high activity waste, require processing and repackaging before characterization and certification for shipment to the Waste Isolation Pilot Plant. LANL is employing a balanced risk approach that accomplishes significant long-term risk reduction by accepting short-term increased facility operations risk under well-developed and justified interim controls. Reviews of facility conditions and additional analyses show that the Waste Characterization, Reduction and Repackaging Facility and the Radioassay and Nondestructive Testing Facility are the most appropriate facilities to safetly remediate, repackage, and ship lower activity and the remaining high activity drums. Updated safety documentation supporting limited Hazard Category 2 operations in these facilities has been developed. Once approved, limited-term operations to process the high activity drums can begin in early 2007, building upon the experience base established performing Hazard Category 3 operations processing lower activity waste in these facilities. LANL is also implementing a series of actions to improve and sustain operations for processing contact-handled transuranic waste inventory. Building 412 Decontamination and Volume Facility and Dom

O'LEARY, GERALD A. [Los Alamos National Laboratory

2007-01-04

40

Energetic Electrons Accelerated in Solar Particle Events Space Sciences Laboratory, University of Berkeley, CA 94720  

E-print Network

Energetic Electrons Accelerated in Solar Particle Events R. P. Lin Space Sciences Laboratory, University of Berkeley, CA 94720 Abstract. New measurements of energetic solar electrons from the WIND range of altitudes. For Large Solar Energetic Particle (LSEP, or so-called gradual) events, WIND

California at Berkeley, University of

41

Photo Credit: Peter GinterSLAC National Accelerator Laboratory Dark Energy  

E-print Network

Photo Credit: Peter GinterSLAC National Accelerator Laboratory #12;Dark Energy 70% Dark Matter 26://janus.astro.umd.edu/SolarSystems/ Planetary Motion Credit: The Astronomy Workshop A collection of interactive web-based programs and Advanced Camera for Surveys #12;Dark Energy 70% Dark Matter 26% Ordinary Matter 4% #12;Dark Energy 70% Dark

Osheroff, Douglas D.

42

Accelerated laboratory corrosion test for materials and finishes used in naval aircraft. Progress report  

Microsoft Academic Search

An accelerated laboratory corrosion test has been developed to screen materials and finishes for use on naval aircraft. Sulfur dioxide is introduced at periodic intervals into a conventional salt fog chamber to simulate conditions produced by the carrier stack gas\\/marine environment. Procedures for conducting the test are described.

Ketcham

1977-01-01

43

Surveying the monument system at Lawrence Berkeley Laboratory`s Advanced Light Source accelerator  

SciTech Connect

Particle accelerators with demanding alignment requirements face a need for periodic re-surveying of their reference monument systems. At the ALS, significant foundation settling and the necessary relocation of some floor monuments mean that the entire system of over 100 monuments must be re-surveyed to an accuracy of 100 microns at two year intervals. Last Fall, the monument survey was conducted entirely by the in-house Survey and Alignment crew using a simplified instrument mounting system and an inexpensive commercial software package. Precision levels, plummets, theodolites, and an electronic distance measuring system were used with the innovative ``Monopod`` instrument mounting system in a cost effective approach to this critical task.

Thur, W.; Lauritzen, T.

1995-04-01

44

Linear induction accelerators at the Los Alamos National Laboratory DARHT facility  

Microsoft Academic Search

The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory consists of two linear induction accelerators at right angles to each other. The First Axis, operating since 1999, produces a nominal 20-MeV, 2-kA single beam-pulse with 60-nsec width. In contrast, the DARHT Second Axis, operating since 2008, produces up to four pulses in a variable pulse format by

Nath; Subrata

2010-01-01

45

Linking accelerated laboratory and outdoor exposure results for PV polymeric materials: a mechanistic study of EVA  

NASA Astrophysics Data System (ADS)

Linking accelerated laboratory test to field performance for predicting the service life of polymeric materials are being investigated at NIST using the reliability-based methodology. Based on this methodology, a successful linkage between the laboratory and field exposure data for a model polymeric material has been made. Recently, this methodology, for the first time, was introduced to the lifetime assessment of PV polymeric materials. In this paper, a mechanistic study of the degradation of three unstabilized model ethylene vinyl acetate (EVA) systems---uncured EVA, cured EVA and laminated EVA---was carried out under accelerated laboratory exposure and outdoor exposure. The NIST SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) was used for the accelerated laboratory tests, and the outdoor exposure was conducted in Gaithersburg, Maryland. Simultaneous multiple stresses, including temperature, relative humidity and UV radiation, were applied individually or in combination during SPHERE exposure. The effects of the environmental factors on the main degradation mechanisms of different EVA systems were investigated. The results showed that the UV radiation was the most important factor for the degradation of EVA and a synergistic effect occurred between UV radiation and relative humidity. A slower degradation rate was observed for the laminated system as a result of limited diffusion of O2 and H2O into EVA. It was also found that the substantial chemical changes of the uncured EVA system did not yield yellowing, which was dramatically different from the peroxide cured EVA system. Additionally, the chemical degradation modes of the three EVA systems exposed outdoors appeared to be similar to those exposed to the SPHERE. The implication of this work to the current test standards was discussed.

Gu, Xiaohong; Pang, Yongyan; Lin, Chiao-Chi; Liu, Kaipeng; Nguyen, Tinh; Chin, Jaonnie W.

2013-09-01

46

MINER?A Project (FNAL e938)'s Mexico Contribution  

NASA Astrophysics Data System (ADS)

The MINER?A Project (http://minerva.fnal.gov) (Main INjector ExpeRiment?A) is an experiment that uses Fermilab NuMI line. Its main goals are measure the interactions neutrino (antineutrino)-Nucleon at low energies, improve neutrino oscillation studies, study the strong dynamics between nucleons and between nuclei (nucleons) and neutrinos, and between nuclei (nucleons) and anti-neutrinos. I report on the current status of MINER?A experiment, studies currently under way, studies that can be done, and the Mexican (Universidad de Guanajuato) participation in MINER?A experiment.

Félix, J.; Zavala, G.; Urrutia, Z.; Higuera, A.; Valencia, E.; Miner?A Collaboration

2011-04-01

47

Operation of the DC current transformer intensity monitors at FNAL during run II  

SciTech Connect

Circulating beam intensity measurements at FNAL are provided by five DC current transformers (DCCT), one per machine. With the exception of the DCCT in the Recycler, all DCCT systems were designed and built at FNAL. This paper presents an overview of both DCCT systems, including the sensor, the electronics, and the front-end instrumentation software, as well as their performance during Run II.

Crisp, J.; Fellenz, B.; Heikkinen, D.; Ibrahim, M.A.; Meyer, T.; Vogel, G.; /Fermilab

2012-01-01

48

Rutting Performance of Airport Hot-Mix Asphalt Characterized by Laboratory Performance Testing, Full-Scale Accelerated Pavement Testing, and Finite Element Modeling  

E-print Network

potential laboratory tests, (b) comparisons of laboratory tests results to full-scale accelerated pavement test results, and (c) analyses of results from finite element simulations. The laboratory study evaluated of the repeated load test, the static creep...

Rushing, John Ford

2014-04-25

49

Beam dynamics studies of the 8 GeV Linac at FNAL  

SciTech Connect

The proposed 8-GeV proton driver (PD) linac at FNAL includes a front end up to {approx}420 MeV operating at 325 MHz and a high energy section at 1300 MHz. A normal conducting RFQ and short CH type resonators are being developed for the initial acceleration of the H-minus or proton beam up to 10 MeV. From 10 MeV to {approx}420 MeV, the voltage gain is provided by superconducting (SC) spoke-loaded cavities. In the high-energy section, the acceleration will be provided by the International Linear Collider (ILC)-style SC elliptical cell cavities. To employ existing, readily available klystrons, an RF power fan out from high-power klystrons to multiple cavities is being developed. The beam dynamics simulation code TRACK, available in both serial and parallel versions, has been updated to include all known H-minus stripping mechanisms to predict the exact location of beam losses. An iterative simulation procedure is being developed to interact with a transient beam loading model taking into account RF feedback and feedforward systems.

Ostroumov, P.N.; Mustapha, B.; /Argonne; Carneiro, J.-P.; /Fermilab

2008-11-01

50

LLNL\\/UC (Lawrence Livermore National Laboratory)\\/(University of California) AMS (accelerator mass spectrometry) facility and research program  

Microsoft Academic Search

The Lawrence Livermore National Laboratory (LLNL) and the University of California (UC) now have in operation a large AMS spectrometer built as part of a new multiuser laboratory centered on an FN tandem. AMS measurements are expected to use half of the beam time of the accelerator. LLNL use of AMS is in research on consequences of energy usage. Examples

J. C. Davis; I. D. Proctor; J. R. Southon; M. W. Caffee; D. W. Heikkinen; M. L. Roberts; T. L. Moore; K. W. Turteltaub; D. E. Nelson; D. H. Loyd; J. S. Vogel

1990-01-01

51

Accelerators  

NSDL National Science Digital Library

What is the purpose of particle accelerators? On this web page, part of a particle physics tutorial, students read that accelerators solve two problems. The accelerators provide an increase in momentum to produce particles of small wavelength, and the fast-moving particles can create new particles when smashed together. A photograph of the inside of a particle accelerator is provided. Copyright 2005 Eisenhower National Clearinghouse

Group, Lawrence B.

2002-01-01

52

Proposed Casey`s Pond Improvement Project, Fermi National Accelerator Laboratory  

SciTech Connect

The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA), evaluating the impacts associated with the proposed Casey`s Pond Improvement Project at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. The improvement project would maximize the efficiency of the Fermilab Industrial Cooling Water (ICW) distribution system, which removes (via evaporation) the thermal load from experimental and other support equipment supporting the high energy physics program at Fermilab. The project would eliminate the risk of overheating during fixed target experiments, ensure that the Illinois Water Quality Standards are consistently achieved and provide needed additional water storage for fire protection. Based on the analysis in the EA, the DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement is not required.

NONE

1995-05-01

53

Proposed low-level radioactive waste handling building at Fermi National Accelerator Laboratory, Batavia, Illinois  

SciTech Connect

The US Department of Energy (DOE) has prepared an Environmental Assessment (EA), evaluating the impacts associated with the proposed Low-Level Radioactive Waste Building at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. As a result of the high energy physics program at Fermilab, small quantities of low-level radioactive wastes are generated. These wastes are collected, sorted and packaged for shipment to an off-site disposal facility in Hanford, Washington. The proposed project includes the construction of a new building to house, all low-level radioactive waste handling operations. The building would provide workspace for five full-time workers. The proposed project would improve the efficiency and safety of the low-level radioactive waste handling at Fermilab by upgrading equipment and consolidating operations into one facility.

NONE

1995-06-01

54

Plasma-Surface Interaction Research At The Cambridge Laboratory Of Accelerator Studies Of Surfaces  

SciTech Connect

The material requirements for plasma-facing components in a nuclear fusion reactor are some of the strictest and most challenging facing us today. These materials are simultaneously exposed to extreme heat loads (20 MW/m{sup 2} steady-state, 1 GW/m{sup 2} in millisecond transients) and particle fluxes (>10{sup 24} m{sup -2} s{sup -1}) while also undergoing high neutron irradiation (10{sup 18} neutrons/m{sup 2} s). At the Cambridge Laboratory of Accelerator Studies of Surfaces (CLASS), many of the most important issues in plasma-surface interaction research, such as plasma-driven material erosion and deposition, material transport and irradiation and hydrogenic retention are investigated with the use of a 1.7 MV tandem ion accelerator. Ion-Beam Analysis (IBA) is used to investigate and quantify changes in materials due to plasma exposure and ion irradiation is used as a proxy for neutron irradiation to investigate plasma-surface interactions for irradiated materials. This report will outline the capabilities and current research activities at CLASS.

Wright, G. M.; Barnard, H. S.; Hartwig, Z. S.; Stahle, P. W.; Sullivan, R. M.; Woller, K. B.; Whyte, D. G. [Plasma Science and Fusion Center, Massachusettes Institute of Technology, 77 Massachusetts Ave. Cambridge, MA, 02139 (United States)

2011-06-01

55

THE CONTINUOUS ELECTRON BEAM ACCELERATOR FACILITY: CEBAF at the Jefferson Laboratory  

NASA Astrophysics Data System (ADS)

The Jefferson Laboratory's superconducting radiofrequency (srf) Continuous Electron Beam Accelerator Facility (CEBAF) provides multi-GeV continuous-wave (cw) beams for experiments at the nuclear and particle physics interface. CEBAF comprises two antiparallel linacs linked by nine recirculation beam lines for up to five passes. By the early 1990s, accelerator installation was proceeding in parallel with commissioning. By the mid-1990s, CEBAF was providing simultaneous beams at different but correlated energies up to 4 GeV to three experimental halls. By 2000, with srf development having raised the average cavity gradient to 7.5 MV/m, energies up to nearly 6 GeV were routine, at 1-150 µA for two halls and 1-100 nA for the other. Also routine are beams of >75% polarization. Physics results have led to new questions about the quark structure of nuclei, and therefore to user demand for a planned 12 GeV upgrade. CEBAF's enabling srf technology is also being applied in other projects.

Leemann, Christoph W.; Douglas, David R.; Krafft, Geoffrey A.

56

A new LabVIEW-based control system for the Naval Research Laboratory Trace Element Accelerator Mass Spectrometer  

SciTech Connect

A new LabVIEW-based control system for the existing tandem accelerator and new AMS components has been implemented at the Trace Element Accelerator Mass Spectrometry (TEAMS) facility at the Naval Research Laboratory. Through the use of Device Interfaces (DIs) distributed along a fiber optic network, virtually every component of the accelerator system can be controlled from any networked computer terminal as well as remotely via modem or the internet. This paper discusses the LabVIEW-based control software, including remote operation, automatic calculation of ion optical component parameters, beam optimization, and data logging and retrieval.

DeTurck, T. M.; Treacy, D. J. Jr.; Knies, D. L.; Grabowski, K. S.; Knoll, C.; Kennedy, C. A.; Hubler, G. K. [University of Maryland, Department of Chemistry, College Park, Maryland 20742 (United States); Naval Research Laboratory, Code 6670, Washington, District of Columbia 20375-5345 (United States)

1999-06-10

57

Data Plots from FNAL-E907: Main Injector Particle Production Experiment (MIPP)  

DOE Data Explorer

There are approximately 40 data plots available to the public from E907. A proposal to upgrade the MIPP experiment (E-P-960) has been deferred. See the MIPP homepage at http://ppd.fnal.gov/experiments/e907/

58

Advocacy for the Archives and History Office of the SLAC National Accelerator Laboratory: Stages and Methods  

SciTech Connect

Advocating for the good of the SLAC Archives and History Office (AHO) has not been a one-time affair, nor has it been a one-method procedure. It has required taking time to ascertain the current and perhaps predict the future climate of the Laboratory, and it has required developing and implementing a portfolio of approaches to the goal of building a stronger archive program by strengthening and appropriately expanding its resources. Among the successful tools in the AHO advocacy portfolio, the Archives Program Review Committee has been the most visible. The Committee and the role it serves as well as other formal and informal advocacy efforts are the focus of this case study My remarks today will begin with a brief introduction to advocacy and outreach as I understand them, and with a description of the Archives and History Office's efforts to understand and work within the corporate culture of the SLAC National Accelerator Laboratory. I will then share with you some of the tools we have employed to advocate for the Archives and History Office programs and activities; and finally, I will talk about how well - or badly - those tools have served us over the past decade.

Deken, Jean Marie; /SLAC

2009-06-19

59

Application of the National Ignition Facility distinguishable-from-background program to accelerator facilities at Lawrence Livermore National Laboratory.  

PubMed

Lawrence Livermore National Laboratory must control potentially activated materials and equipment in accordance with U.S. Department of Energy (DOE) Order 458.1, Radiation Protection of the Public and the Environment, which requires DOE approval of the process used to release volumetrically contaminated personal property and establishes a dose constraint of 10 µSv y(-1) (1 mrem y(-1)) for clearance of such property. The National Ignition Facility at Lawrence Livermore National Laboratory developed a technical basis document and protocol for determining the radiological status of property that is potentially activated from exposure to neutron radiation produced via fusion of tritium and deuterium. The technical basis included assessment of the neutron energy, the type of materials potentially exposed and the likely activation products, and the sensitivity of radiation detectors used to survey the property. This paper evaluates the National Ignition Facility technical basis document for applicability to the release of property from Lawrence Livermore National Laboratory's various accelerator facilities considering the different types of particles accelerated, radiations produced, and resultant activation products. Extensive process knowledge regarding the accelerators' operations, accompanied by years of routine surveys, provides an excellent characterization of these facilities. Activation studies conducted at the Stanford Linear Accelerator and the High Energy Accelerator Research Organization in Japan corroborate that the long-lived radionuclides produced at accelerator facilities are of the same variety produced at the National Ignition Facility. Consequently, Lawrence Livermore National Laboratory concludes that the release protocol developed for the National Ignition Facility can be used appropriately at all its accelerator facilities. PMID:23629069

Packard, Eric D; Mac Kenzie, Carolyn

2013-06-01

60

Radio frequency systems for present and future accelerators  

SciTech Connect

Rf systems are described for the FNAL Main Ring and Tevatron Ring, CERN SPS and LEP, and HERA proton acceleration system, CERN PS e/sup +/e/sup minus/ acceleration system, and CERN EPA monochromatic cavity. Low impedance rf systems in CERN ISR, the Brookhaven CBA, and SSC are also discussed.

Raka, E.C.

1987-01-01

61

Earthquake Dynamics in Laboratory Model and Simulation - Accelerated Creep as Precursor of Instabilities  

NASA Astrophysics Data System (ADS)

Shallow earthquakes can be considered as a result of tribological instabilities, so called stick-slip behaviour [1,2], meaning that sudden slip occurs at already existing rupture zones. From a contact mechanics point of view it is clear, that no motion can arise completely sudden, the material will always creep in an existing contact in the load direction before breaking loose. If there is a measureable creep before the instability, this could serve as a precursor. To examine this theory in detail, we built up an elementary laboratory model with pronounced stick-slip behaviour. Different material pairings, such as steel-steel, steel-glass and marble-granite, were analysed at different driving force rates. The displacement was measured with a resolution of 8 nm. We were able to show that a measureable accelerated creep precedes the instability. Near the instability, this creep is sufficiently regular to serve as a basis for a highly accurate prediction of the onset of macroscopic slip [3]. In our model a prediction is possible within the last few percents of the preceding stick time. We are hopeful to extend this period. Furthermore, we showed that the slow creep as well as the fast slip can be described very well by the Dieterich-Ruina-friction law, if we include the contribution of local contact rigidity. The simulation meets the experimental curves over five orders of magnitude. This friction law was originally formulated for rocks [4,5] and takes into account the dependency of the coefficient of friction on the sliding velocity and on the contact history. The simulations using the Dieterich-Ruina-friction law back up the observation of a universal behaviour of the creep's acceleration. We are working on several extensions of our model to more dimensions in order to move closer towards representing a full three-dimensional continuum. The first step will be an extension to two degrees of freedom to analyse the interdependencies of the instabilities. We also plan to install a larger system which is capable of performing events of different spatial extent and magnitude. [1] Stick-Slip as a Mechanism for Earthquakes. Brace, W.F. und Byerlee, J.D. 1966, Science, Bd. 153, S. 990-992. [2] Detailed Studies of Frictional Sliding of Granite and Implications for the Earthquake Mechanism. Scholz, C. H., Molnar, P. und Johnson, T. 32, 1972, Journal of Geophysical Research, Bd. 77, S. 6392-6409. [3] Accelerated Creep as a Precursor of Friction Instability and Earthquake Prediction. Popov, V. L., et al. 2010, Physical Mesomechanics, Bd. 13, S. 283-291. [4] Modeling of Rock Friction, Part 1: Experimental Results and Constitutive Equations. Dieterich, J.H. B5, 1979, Journal of Geophysical Research, Bd. 84, S. 2161-2168. [5] State Instability and State Variable Friction Law. Ruina, A. B12, 1983, Journal of Geophysical Research, Bd. 88, S. 10359-10370.

Grzemba, B.; Popov, V. L.; Starcevic, J.; Popov, M.

2012-04-01

62

Analysis of spatially-resolved M-shell W spectra produced on the Z-accelerator at Sandia National Laboratories  

Microsoft Academic Search

Tungsten wire explosions are being intensively studied at Sandia National Laboratories. High-resolution spatially-resolved x-ray spectral data have been accumulated in tungsten experiments on the SNL-Z accelerator, which require a development of the appropriate theoretical modeling. The University of Nevada, Reno, has developed a collisional-radiative atomic kinetic model which includes the ground states of every ionization stage of W from the

A. S. Shlyaptseva; S. M. Hamasha; S. B. Hansen; J. E. Bailey; P. W. Lake; D. S. Nielsen; W. A. Stygar; P. D. Lepell; T. J. Nash; C. Deeney; U. I. Safronova

2002-01-01

63

LLNL/UC (Lawrence Livermore National Laboratory)/(University of California) AMS (accelerator mass spectrometry) facility and research program  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) and the University of California (UC) now have in operation a large AMS spectrometer built as part of a new multiuser laboratory centered on an FN tandem. AMS measurements are expected to use half of the beam time of the accelerator. LLNL use of AMS is in research on consequences of energy usage. Examples include global warming, geophysical site characterization, radiation biology and dosimetry, and study of mutagenic and carcinogenic processes. UC research activities are in clinical applications, archaeology and anthropology, oceanography, and geophysical and geochemical research. Access is also possible for researchers outside the UC system. The technological focus of the laboratory is on achieving high rates of sample through-put, unattended operation, and advances in sample preparation methods. Because of the expected growth in the research programs and the other obligations of the present accelerator, we are designing a follow-on dedicated facility for only AMS and microprobe analysis that will contain at least two accelerators with multiple spectrometers. 10 refs., 1 fig.

Davis, J.C.; Proctor, I.D.; Southon, J.R.; Caffee, M.W.; Heikkinen, D.W.; Roberts, M.L.; Moore, T.L.; Turteltaub, K.W.; Nelson, D.E.; Loyd, D.H.; Vogel, J.S.

1990-04-18

64

Laboratory simulation of axial and angular projectile accelerations in a rifled gun barrel  

Microsoft Academic Search

A new test technique has been proposed for simulating both the linear and angular acceleration shocks produced during artillery shots. This technique uses a two mass fixture with a screw connection between the two masses. An axial force applied to the first mass is transmitted to the second mass through the screw connection which produces an axial and angular acceleration

N. T. Davie; R. G. Bell

1988-01-01

65

Laboratory simulation of axial and angular projectile accelerations in a rifled gun barrel  

SciTech Connect

A new test technique has been proposed for simulating both the linear and angular acceleration shocks produced during artillery shots. This technique uses a two mass fixture with a screw connection between the two masses. An axial force applied to the first mass is transmitted to the second mass through the screw connection which produces an axial and angular acceleration on the second mass. The ratio of axial to angular acceleration can be controlled by variation in mass properties of the two mass fixture. A simple fixture was constructed to verify the test concept at low shock levels. Test results using this fixture are shown. 1 ref., 6 figs.

Davie, N.T.; Bell, R.G.

1988-01-01

66

Do sediment type and test durations affect results of laboratory-based, accelerated testing studies of permeable pavement clogging?  

PubMed

Previous studies have attempted to quantify the clogging processes of Permeable Interlocking Concrete Pavers (PICPs) using accelerated testing methods. However, the results have been variable. This study investigated the effects that three different sediment types (natural and silica), and different simulated rainfall intensities, and testing durations had on the observed clogging processes (and measured surface infiltration rates) of laboratory-based, accelerated PICP testing studies. Results showed that accelerated simulated laboratory testing results are highly dependent on the type, and size of sediment used in the experiments. For example, when using real stormwater sediment up to 1.18mm in size, the results showed that neither testing duration, nor stormwater application rate had any significant effect on PICP clogging. However, the study clearly showed that shorter testing durations generally increased clogging and reduced the surface infiltration rates of the models when artificial silica sediment was used. Longer testing durations also generally increased clogging of the models when using fine sediment (<300?m). Results from this study will help researchers and designers better anticipate when and why PICPs are susceptible to clogging, reduce maintenance and extend the useful life of these increasingly common stormwater best management practices. PMID:25618819

Nichols, Peter W B; White, Richard; Lucke, Terry

2015-04-01

67

Progress on electron cloud effects calculations for the FNAL main injector Kiran G. Sonnad,  

E-print Network

at any number of points in the storage ring which are referred to here as "stations." The evolutionLBNL-767E Progress on electron cloud effects calculations for the FNAL main injector Kiran G for the Fermilab Main Injector using the Quasistatic Model [1] implemented into the particle-in-cell code Warp [2

Furman, Miguel

68

Department of Energy finding of no significant impact, Low Energy Demonstration Accelerator, Los Alamos National Laboratory  

SciTech Connect

As part of the DOE`s need to maintain the capability of producing tritium in support of its historic and near-term stewardship of the nation`s nuclear weapons stockpile, the agency has recently completed a Programmatic Environmental Impact Statement for Tritium Supply and Recycling. The Environmental Assessment (EA) for the Low Energy Demonstration Accelerator (LEDA) at Technical Area (TA) 53, LANL, Los Alamos, New Mexico (DOE-EA-1147), March 1996, analyzes the DOE proposal to design, build, and test critical prototypical components of the accelerator system for tritium production, specifically the front-end, low-energy section of the accelerator at LANL. LEDA would be incrementally developed and tested in five separate stages over the next seven years. LEDA would be located at an existing building at TA-53; the LEDA components would be tested in order to verify equipment and prototype design and resolve related performance and production issues for future full-scale operation at Savannah River Site (SRS) in the event the APT plant is built. Production operations would not occur at LANL under the proposed action. The US DOE finds that there would be no significant impact from proceeding with its proposal to design, build, and test critical prototypical components of the accelerator system for tritium production, specifically the front-end, low-energy section of the accelerator, at TA-53, LANL. Based on the environmental assessment that analyses the potential environmental effects that would be expected to occur if the DOE were to design, build, and test prototypical components of the accelerator system for tritium production, the proposed action does not constitute a major federal action which would significantly affect the human environment within the meaning of NEPA. Therefore, no environmental impact statement is required for this proposal.

NONE

1996-08-01

69

DEVELOPMENT OF A HIGH BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT BROOKHAVEN NATIONAL LABORATORY*  

E-print Network

954 DEVELOPMENT OF A HIGH BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT BROOKHAVEN, New York 11973 and K. McDonald Princeton [Jniversity Abstract An electron gun utilizing a radio). Here we report on the de;$n of the electron gun which will provide r.f. bunches of up to 10 electrons

McDonald, Kirk

70

Surveying the a monument system at Lawrence Berkeley Laboratory's Advanced Light Source accelerator  

Microsoft Academic Search

Particle accelerators with demanding alignment requirements face a need for periodic re-surveying of their reference monument systems. At the ALS, significant foundation settling and the necessary relocation of some floor monuments mean that the entire system of over 100 monuments must be re-surveyed to an accuracy of 100 microns at two year intervals. Last Fall, the monument survey was conducted

W. Thur; Ted Lauritzen

1995-01-01

71

Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasma  

SciTech Connect

Bulk ion acceleration and particle heating during magnetic reconnection are studied in the collisionless plasma of the Magnetic Reconnection Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from that of the electrons within the ion diffusion region. The reconnection process studied here is quasi-symmetric since plasma parameters such as the magnitude of the reconnecting magnetic field, the plasma density, and temperature are compatible on each side of the current sheet. Our experimental data show that the in-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential that produces the in-plane electric field is established by electrons that are accelerated near the electron diffusion region. The in-plane profile of this electrostatic potential shows a “well” structure along the direction normal to the reconnection current sheet. This well becomes deeper and wider downstream as its boundary expands along the separatrices where the in-plane electric field is strongest. Since the in-plane electric field is 3–4 times larger than the out-of-plane reconnection electric field, it is the primary source of energy for the unmagnetized ions. With regard to ion acceleration, the Hall electric field causes ions near separatrices to be ballistically accelerated toward the outflow direction. Ion heating occurs as the accelerated ions travel into the high pressure downstream region. This downstream ion heating cannot be explained by classical, unmagnetized transport theory; instead, we conclude that ions are heated by re-magnetization of ions in the reconnection exhaust and collisions. Two-dimensional (2-D) simulations with the global geometry similar to MRX demonstrate downstream ion thermalization by the above mechanisms. Electrons are also significantly heated during reconnection. The electron temperature sharply increases across the separatrices and peaks just outside of the electron diffusion region. Unlike ions, electrons acquire energy mostly from the reconnection electric field, and the energy gain is localized near the X-point. However, the increase in the electron bulk flow energy remains negligible. These observations support the assertion that efficient electron heating mechanisms exist around the electron diffusion region and that the heat generated there is quickly transported along the magnetic field due to the high parallel thermal conductivity of electrons. Classical Ohmic dissipation based on the perpendicular Spitzer resistivity is too small to balance the measured heat flux, indicating the presence of anomalous electron heating.

Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Jara-Almonte, Jonathan; Myers, Clayton E. [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2014-05-15

72

Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasmaa)  

NASA Astrophysics Data System (ADS)

Bulk ion acceleration and particle heating during magnetic reconnection are studied in the collisionless plasma of the Magnetic Reconnection Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from that of the electrons within the ion diffusion region. The reconnection process studied here is quasi-symmetric since plasma parameters such as the magnitude of the reconnecting magnetic field, the plasma density, and temperature are compatible on each side of the current sheet. Our experimental data show that the in-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential that produces the in-plane electric field is established by electrons that are accelerated near the electron diffusion region. The in-plane profile of this electrostatic potential shows a "well" structure along the direction normal to the reconnection current sheet. This well becomes deeper and wider downstream as its boundary expands along the separatrices where the in-plane electric field is strongest. Since the in-plane electric field is 3-4 times larger than the out-of-plane reconnection electric field, it is the primary source of energy for the unmagnetized ions. With regard to ion acceleration, the Hall electric field causes ions near separatrices to be ballistically accelerated toward the outflow direction. Ion heating occurs as the accelerated ions travel into the high pressure downstream region. This downstream ion heating cannot be explained by classical, unmagnetized transport theory; instead, we conclude that ions are heated by re-magnetization of ions in the reconnection exhaust and collisions. Two-dimensional (2-D) simulations with the global geometry similar to MRX demonstrate downstream ion thermalization by the above mechanisms. Electrons are also significantly heated during reconnection. The electron temperature sharply increases across the separatrices and peaks just outside of the electron diffusion region. Unlike ions, electrons acquire energy mostly from the reconnection electric field, and the energy gain is localized near the X-point. However, the increase in the electron bulk flow energy remains negligible. These observations support the assertion that efficient electron heating mechanisms exist around the electron diffusion region and that the heat generated there is quickly transported along the magnetic field due to the high parallel thermal conductivity of electrons. Classical Ohmic dissipation based on the perpendicular Spitzer resistivity is too small to balance the measured heat flux, indicating the presence of anomalous electron heating.

Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Jara-Almonte, Jonathan; Myers, Clayton E.

2014-05-01

73

Cosmetic corrosion of painted aluminum and steel automotive body sheet: Results from outdoor and accelerated laboratory test methods  

SciTech Connect

In recent years, increasing attention has been given to the need to develop an accelerated laboratory test method(s) for cosmetic corrosion of painted panels that realistically simulate in-service exposure. Much of that work has focused on steel substrates. The purpose of this research is to compare the corrosion performance of painted aluminum and steel sheet as determined om various laboratory methods and in-service exposure, and to develop a realistic accelerated test method for evaluation of the cosmetic corrosion of painted aluminum. Several aluminum sheet products from the 2xxx, 5xxx, and 6xxx alloy series have been tested. The steel substrates are similar to those used in other programs. The test methods chosen represent a cross-section of methods common to the automotive and aluminum industries for evaluation of painted sheet metal products. The results indicate that there is considerable difference in the relative correlation of various test methods to in-service exposure. In addition, there is considerable difference in the relative magnitudes and morphologies of corrosion, and occasionally in the relative rankings, as a function of test method. The influence of alloy composition and zinc phosphate coating weight are also discussed.

Moran, J.P.; Ziman, P.R.; Egbert, M.W. [Alcoa Technical Center, Alcoa Center, PA (United States). Alloy Technology Division

1995-11-01

74

Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments  

USGS Publications Warehouse

After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

Chang, Jefferson C.; Lockner, David A.; Reches, Z.

2012-01-01

75

Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments  

NASA Astrophysics Data System (ADS)

We simulated the slip of a fault-patch during a large earthquake by rapidly loading an experimental, ring-shaped fault with energy stored in a spinning flywheel. The flywheel abruptly delivers a finite amount of energy by spinning the fault-patch that spontaneously dissipates the energy without operator intervention. We conducted 42 experiments on Sierra White granite (SWG) samples, and 24 experiments on Kasota dolomite (KD) samples. Each experiment starts by spinning a 225 kg disk-shaped flywheel to a prescribed angular velocity. We refer to this experiment as an "earthquake-like slip-event" (ELSE). The strength-evolution in ELSE experiments is similar to the strength-evolution proposed for earthquake models and observed in stick-slip experiments. Further, we found that ELSE experiments are similar to earthquakes in at least three ways: (1) slip driven by the release of a finite amount of stored energy; (2) pattern of fault strength evolution; and (3) seismically observed values, such as average slip, peak-velocity and rise-time. By assuming that the measured slip, D, in ELSE experiments is equivalent to the average slip during an earthquake, we found that ELSE experiments (D = 0.003-4.6 m) correspond to earthquakes in moment-magnitude range of Mw = 4-8. In ELSE experiments, the critical-slip-distance, dc, has mean values of 2.7 cm and 1.2 cm for SWG and KD, that are much shorter than the 1-10 m in steady-state classical experiments in rotary shear systems. We attribute these dc values, to ELSE loading in which the fault-patch is abruptly loaded by impact with a spinning flywheel. Under this loading, the friction-velocity relations are strikingly different from those under steady-state loading on the same rock samples with the same shear system (Reches and Lockner, Nature, 2010). We further note that the slip acceleration in ELSE evolves systematically with fault strength and wear-rate, and that the dynamic weakening is restricted to the period of intense acceleration (up to 25 m/s2 during ~0.1 s). Thus, the weakening distance, dc, is reached within the initial acceleration spike. These observations are not unique, and similar weakening-acceleration associations were reported in stick-slip, rotary shear, and impact shear experiments. These studies greatly differ from each other in slip distance, normal stress, acceleration, and slip-velocities with the outstanding commonality of abrupt loading and intense acceleration. We propose that impact loading induces extremely high strain-rates that significantly increase rock brittleness, fracture tendency, and fragmentation. We envision that these processes intensify fault wear as manifested in ELSE experiments by extremely high initial wear-rates. This intense, early wear generates a layer of fine-grain gouge that reduces the fault strength by powder-lubrication. Our analysis indicates that rapid acceleration associated with earthquake rupture accelerates fault weakening and shortens the weakening-distance.

Chang, J. C.; Lockner, D. A.; Reches, Z.

2012-12-01

76

Test of a coaxial blade tuner at HTS FNAL  

SciTech Connect

A coaxial blade tuner has been selected for the 1.3GHz SRF cavities of the Fermilab SRF Accelerator Test Facility. Results from tuner cold tests in the Fermilab Horizontal Test Stand are presented. Fermilab is constructing the SRF Accelerator Test Facility, a facility for accelerator physics research and development. This facility will contain a total of six cryomodules, each containing eight 1.3 GHz nine-cell elliptical cavities. Each cavity will be equipped with a Slim Blade Tuner designed by INFN Milan. The blade tuner incorporates both a stepper motor and piezo actuators to allow for both slow and fast cavity tuning. The stepper motor allows the cavity frequency to be statically tuned over a range of 500 kHz with an accuracy of several Hz. The piezos provide up to 2 kHz of dynamic tuning for compensation of Lorentz force detuning and variations in the He bath pressure. The first eight blade tuners were built at INFN Milan, but the remainder are being manufactured commercially following the INFN design. To date, more than 40 of the commercial tuners have been delivered.

Pischalnikov, Y.; Barbanotti, S.; Harms, E.; Hocker, A.; Khabiboulline, T.; Schappert, W.; /Fermilab; Bosotti, A.; Pagani, C.; Paparella, R.; /LASA, Segrate

2011-03-01

77

Status of the darht 2nd axis accelerator at the Los Alamos national laboratory  

Microsoft Academic Search

The Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) was constructed at Los Alamos National Laboratory as a radiographic facility to provide dual-axis multi-time radiography to support the US Stockpile Stewardship Program. The DARHT 1st Axis has been operational since 1999 and has been providing excellent radiographs. The DARHT 2nd Axis construction project was completed in early 2003. However, during the

R. D. Scarpetti?; S. Nath; J. Barraza; C. A. Ekdahl; E. Jacquez; B. T. McCuistian; K. Nielsen; M. Schulze; J. Seitz; G. J. Caporaso; Y.-J. Chen; G. Logan; F. Bieniosek

2007-01-01

78

Future directions in controlling the LAMPF-PSR Accelerator Complex at Los Alamos National Laboratory  

SciTech Connect

Four interrelated projects are underway whose purpose is to migrate the LAMPF-PSR Accelerator Complex control systems to a system with a common set of hardware and software components. Project goals address problems in performance, maintenance and growth potential. Front-end hardware, operator interface hardware and software, computer systems, network systems and data system software are being simultaneously upgraded as part of these efforts. The efforts are being coordinated to provide for a smooth and timely migration to a client-sever model-based data acquisition and control system. An increased use of the distributed intelligence at both the front-end and operator interface is a key element of the projects. 2 refs., 2 figs.

Stuewe, R.; Schaller, S.; Bjorklund, E.; Burns, M.; Callaway, T.; Carr, G.; Cohen, S.; Kubicek, D.; Harrington, M.; Poore, R.; Schultz, D.

1991-01-01

79

ACCELERATED SITE TECHNOLOGY DEPLOYMENT COST AND PERFORMANCE REPORT COMPARABILITY OF ISOCS INSTRUMENT IN RADIONUCLIDE CHARACTERICATION AT BROOKHAVEN NATIONAL LABORATORY  

SciTech Connect

This report describes a DOE Accelerated Site Technology Deployment project being conducted at Brookhaven National Laboratory to deploy innovative, radiological, in situ analytical techniques. The technologies are being deployed in support of efforts to characterize the Brookhaven Graphite Research Reactor (BGRR) facility, which is currently undergoing decontamination and decommissioning. This report focuses on the deployment of the Canberra Industries In Situ Object Counting System (ISOCS) and assesses its data comparability to baseline methods of sampling and laboratory analysis. The battery-operated, field deployable gamma spectrometer provides traditional spectra of counts as a function of gamma energy. The spectra are then converted to radionuclide concentration by applying innovative efficiency calculations using monte carlo statistical methods and pre-defined geometry templates in the analysis software. Measurement of gamma emitting radionuclides has been accomplished during characterization of several BGRR components including the Pile Fan Sump, Above Ground Ducts, contaminated cooling fans, and graphite pile internals. Cs-137 is the predominant gamma-emitting radionuclide identified, with smaller quantities of Co-60 and Am-241 detected. The Project used the Multi-Agency Radiation Survey and Site Investigation Manual guidance and the Data Quality Objectives process to provide direction for survey planning and data quality assessment. Analytical results have been used to calculate data quality indicators (DQI) for the ISOCS measurements. Among the DQIs assessed in the report are sensitivity, accuracy, precision, bias, and minimum detectable concentration. The assessment of the in situ data quality using the DQIs demonstrates that the ISOCS data quality can be comparable to definitive level laboratory analysis when the field instrument is supported by an appropriate Quality Assurance Project Plan. A discussion of the results obtained by ISOCS analysis of objects that could not be analyzed readily by conventional methods demonstrates a powerful application of the instrument. In conclusion, a comparison of costs associated with the analysis on the ISOCS instrument to the costs of conventional sampling and laboratory analysis is presented.

KALB,P.; LUCKETT,L.; MILLER,K.; GOGOLAK,C.; MILIAN,L.

2001-03-01

80

World pendulum—a distributed remotely controlled laboratory (RCL) to measure the Earth's gravitational acceleration depending on geographical latitude  

NASA Astrophysics Data System (ADS)

We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration (accuracy ?g ~ 0.01 m s-2). Each pendulum can be remotely controlled via the internet by a computer located somewhere on Earth. The theoretical part describes the physical origin of this phenomenon g(phiv), that the Earth's effective gravitational acceleration g depends on the angle of latitude phiv. Then, we present all necessary formula to deduce g(phiv) from oscillations of a string pendulum. The technical part explains tips and tricks to realize such an apparatus to measure all necessary values with sufficient accuracy. In addition, we justify the precise dimensions of a physical pendulum such that the formula for a mathematical pendulum is applicable to determine g(phiv) without introducing errors. To conclude, we describe the internet version—the string pendulum as a remotely controlled laboratory. The teaching relevance and educational value will be discussed in detail at the end of this paper including global experimenting, using the internet and communication techniques in teaching and new ways of teaching and learning methods.

Gröber, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

2007-05-01

81

SLAC NATIONAL ACCELERATOR LABORATORY 2575 SAND HILL ROAD MENLO PARK CALIFORNIA 94025 USA SLAC is operated by Stanford University for the U.S. Department of Energy  

E-print Network

SLAC NATIONAL ACCELERATOR LABORATORY · 2575 SAND HILL ROAD · MENLO PARK · CALIFORNIA · 94025 · USA.S. Agent) at 2575 Sand Hill Road, Menlo Park, CA 94025 to act as a lawful U.S. agent on my behalf. From

Wechsler, Risa H.

82

Analysis of spatially-resolved M-shell W spectra produced on the Z-accelerator at Sandia National Laboratories.  

NASA Astrophysics Data System (ADS)

Tungsten wire explosions are being intensively studied at Sandia National Laboratories. High-resolution spatially-resolved x-ray spectral data have been accumulated in tungsten experiments on the SNL-Z accelerator, which require a development of the appropriate theoretical modeling. The University of Nevada, Reno, has developed a collisional-radiative atomic kinetic model which includes the ground states of every ionization stage of W from the bare ion to the neutral W. Detailed atomic structure is included for ionization stages from V-like to Se-like W. The presented work focuses on the application of this model to interpretation of spatially-resolved M-shell W spectra collected in a tungsten shot Z543. These spectra cover the broad spectral region from 3.5 up to 7.5 Åand indicate three distinctive spectral regions. These three regions are composed from different groups of transitions 3l - 4l',5l'' and show different sensitivity to plasma parameters and opacity effects. The complete modeling of this spectrum allows a detailed diagnostic of a hotter plasma core in z-pinch experiments involving heavy ions.

Shlyaptseva, A. S.; Hamasha, S. M.; Hansen, S. B.; Bailey, J. E.; Lake, P. W.; Nielsen, D. S.; Stygar, W. A.; Lepell, P. D.; Nash, T. J.; Deeney, C.; Safronova, U. I.

2002-11-01

83

Do you want to build such a machine? : Designing a high energy proton accelerator for Argonne National Laboratory.  

SciTech Connect

Argonne National Laboratory's efforts toward researching, proposing and then building a high-energy proton accelerator have been discussed in a handful of studies. In the main, these have concentrated on the intense maneuvering amongst politicians, universities, government agencies, outside corporations, and laboratory officials to obtain (or block) approval and/or funds or to establish who would have control over budgets and research programs. These ''top-down'' studies are very important but they can also serve to divorce such proceedings from the individuals actually involved in the ground-level research which physically served to create theories, designs, machines, and experiments. This can lead to a skewed picture, on the one hand, of a lack of effect that so-called scientific and technological factors exert and, on the other hand, of the apparent separation of the so-called social or political from the concrete practice of doing physics. An exception to this approach can be found in the proceedings of a conference on ''History of the ZGS'' held at Argonne at the time of the Zero Gradient Synchrotron's decommissioning in 1979. These accounts insert the individuals quite literally as they are, for the most part, personal reminiscences of those who took part in these efforts on the ground level. As such, they are invaluable raw material for historical inquiry but generally lack the rigor and perspective expected in a finished historical work. The session on ''Constructing Cold War Physics'' at the 2002 annual History of Science Society Meeting served to highlight new approaches circulating towards history of science and technology in the post-WWII period, especially in the 1950s. There is new attention towards the effects of training large numbers of scientists and engineers as well as the caution not to equate ''national security'' with military preparedness, but rather more broadly--at certain points--with the explicit ''struggle for the hearts and minds of men.'' There is a call for greater detail in periodization as events such as Stalin's death and Khruschev's subsequent speech, the end of the Korean conflict, the hydrogen bomb test, Eisenhower's Atoms for Peace initiative, the 1955 Geneva conference, and Sputnik each served to drastically change the landscape in the United States. Furthermore, Harvard University Press recently published the first detailed and scholarly account of a history of the national laboratories; the work argues that the ''systemicity'' of the organization must be considered as a necessary piece when examining any of the myriad of related puzzles.

Paris, E.

2004-04-05

84

The NESSiE way to searches for sterile neutrinos at FNAL  

E-print Network

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle $\\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. Its recent proposal refers to the use of magnetic spectrometers at two different sites, Near and Far ones. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the undergoing project of a multi-site Liquid-Argon detectors at FNAL. The experiment to be possibly setup at Booster will allow to definitively clarify the current $\

L. Stanco; A. Anokhina; A. Bagulya; M. Benettoni; P. Bernardini; R. Brugnera; M. Calabrese; A. Cecchetti; S. Cecchini; M. Chernyavskiy; P. Creti; F. Dal Corso; O. Dalkarov; A. Del Prete; G. De Robertis; M. De Serio; L. Degli Esposti; D. Di Ferdinando; S. Dusini; T. Dzhatdoev; C. Fanin; R. A. Fini; G. Fiore; A. Garfagnini; S. Golovanov; M. Guerzoni; B. Klicek; U. Kose; K. Jakovcic; G. Laurenti; I. Lippi; F. Loddo; A. Longhin; M. Malenica; G. Mancarella; G. Mandriol; A. Margiotta; G. Marsella; N. Mauri; E. Medinaceli; A. Mengucci; R. Mingazheva; O. Morgunova; M. T. Muciaccia; M. Nessi; D. Orecchini; A. Paoloni; G. Papadia; L. Paparella; L. Pasqualini; A. Pastore; L. Patrizii; N. Polukhina; M. Pozzato; M. Roda; T. Roganova; G. Rosa; Z. Sahnoun; S. Simone; C. Sirignano; G. Sirri; M. Spurio; N. Starkov; M. Stipcevic; A. Surdo; M. Tenti; V. Togo; M. Ventura; M. Vladymyrov

2014-10-15

85

Prospects for the measurement of muon-neutrino disappearance at the FNAL-Booster  

E-print Network

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle $\\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. This proposal refers to the use of magnetic spectrometers at two different sites, Near and Far. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the CERN project for a new more performant neutrino beam, which will nicely extend the physics results achievable at the Booster. The possible FNAL experiment will allow to clarify the current $\

A. Anokhina; A. Bagulya; M. Benettoni; P. Bernardini; R. Brugnera; M. Calabrese; A. Cecchetti; S. Cecchini; M. Chernyavskiy; P. Creti; F. Dal Corso; O. Dalkarov; A. Del Prete; G. De Robertis; M. De Serio; L. Degli Esposti; D. Di Ferdinando; S. Dusini; T. Dzhatdoev; C. Fanin; R. A. Fini; G. Fiore; A. Garfagnini; S. Golovanov; M. Guerzoni; B. Klicek; U. Kose; K. Jakovcic; G. Laurent; I. Lippi; F. Loddo; A. Longhin; M. Malenica; G. Mancarella; G. Mandrioli; A. Margiotta; G. Marsella; N. Mauri; E. Medinaceli; A. Mengucci; R. Mingazheva; O. Morgunova; M. T. Muciaccia; M. Nessi; D. Orecchini; A. Paoloni; G. Papadia; L. Paparella; L. Pasqualini; A. Pastore; L. Patrizii; N. Polukhina; M. Pozzato; M. Roda; T. Roganova; G. Rosa; Z. Sahnoun; S. Simone; C. Sirignano; G. Sirri; M. Spurio; L. Stanco; N. Starkov; M. Stipcevic; A. Surdo; M. Tenti; V. Togo; M. Ventura; M. Vladymyrov

2014-04-09

86

Note: Recent achievements at the 60-MeV Linac for sub-picosecond terahertz radiation at the Pohang Accelerator Laboratory  

SciTech Connect

A femtosecond (fs) terahertz (THz) linac has been constructed to generate fs-THz radiation by using ultrashort electron beam at the Pohang Accelerator Laboratory. To generate an ultrashort electron beam with 60-MeV energy, a chicane bunch compressor has been adopted. Simulation studies have been conducted to design the linac. In this note, recent achievements at 60-MeV linac are presented.

Yim, Changmook; Hong, Juho; Parc, Yongwoon; Ko, In Soo [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Jung, Seonghoon; Park, Jaehun; Kang, Heung-Sik [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of); Han, Daehun [Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Ryu, Jaehyun [Department of Chemistry, POSTECH, Pohang 790-784 (Korea, Republic of)

2011-10-15

87

Design of 325 MHz single and triple spoke resonators at FNAL  

SciTech Connect

The proposed 8-GeV driver at FNAL is based on approximately 400 independently phased SC resonators. In this paper the design of 325 MHz Spoke Resonators, two single spoke resonators ({beta}=0.22 and {beta}=0.4) and a triple spoke resonator ({beta}=0.62), for the High Intensity Neutrino Source (HINS) front end is presented. We describe the optimization of the spoke resonators geometry, the goal being to minimize the E{sub peak}/E{sub acc} and B{sub peak}/E{sub acc} ratios. We report on the coupled ANSYS-MWS analysis on the resonators mechanical properties and power coupler RF design. The current status of mechanical design, slow tuning mechanism and cryostat are also presented.

Lanfranco, G.; Apollinari, G.; Gonin, I.; Khabiboulline, T.; McConologue, F.; Romanov, G.; Wagner, R.; /Fermilab

2006-08-01

88

CP AND CPT SYMMETRY TESTS FROM THE TWOPION DECAYS OF THE NEUTRAL KAON WITH THE FNAL E731  

E-print Network

. Woods zz and H. Yamamoto z The Enrico Fermi Institute and the Department of Physics, The University E.C. Swallow Department of Physics, Elmhurst College, Elmhurst, Illinois 60126 and The Enrico Fermi. Stanfield, R. Tschirhart and T. Yamanaka ---- Fermi National Accelerator Laboratory, Batavia, Illinois 60510

Fermilab

89

Recent experience in the fabrication and brazing of ceramic beam tubes for kicker magnets at FNAL  

SciTech Connect

Ceramic beam tubes are utilized in numerous kicker magnets in different accelerator rings at Fermi National Accelerator Laboratory. Kovar flanges are brazed onto each beam tube end, since kovar and high alumina ceramic have similar expansion curves. The tube, kovar flange, end piece, and braze foil (titanium/incusil) alloy brazing material are stacked in the furnace and then brazed in the furnace at 1000 C. The ceramic specified is 99.8% Alumina, Al{sub 2}O{sub 3}, a strong recrystallized high-alumina fabricated by slip casting. Recent experience at Fermilab with the fabrication and brazing of these tubes has brought to light numerous problems including tube breakage and cracking and also the difficulty of brazing the tube to produce a leak-tight joint. These problems may be due to the ceramic quality, voids in the ceramic, thinness of the wall, and micro-cracks in the ends which make it difficult to braze because it cannot fill tiny surface cracks which are caused by grain pullout during the cutting process. Solutions which are being investigated include lapping the ends of the tubes before brazing to eliminate the micro-cracks and also metallization of the tubes.

Ader, C.R.; Jensen, C.; Reilly, R.; Snee, D.; Wilson, J.H.; /Fermilab

2008-06-01

90

World Pendulum--A Distributed Remotely Controlled Laboratory (RCL) to Measure the Earth's Gravitational Acceleration Depending on Geographical Latitude  

ERIC Educational Resources Information Center

We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration (accuracy [delta]g is approximately equal to 0.01 m s[superscript -2]). Each pendulum can be remotely controlled via the internet by a computer located somewhere on Earth. The theoretical part describes…

Grober, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

2007-01-01

91

Statistical correlation of the soil incubation and the accelerated laboratory extraction methods to estimate nitrogen release rates of slow- and controlled-release fertilizers.  

PubMed

Several technologies have been proposed to characterize the nutrient release patterns of enhanced-efficiency fertilizers (EEFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize nutrient release of slow-release fertilizer (SRF) and controlled-release fertilizer (CRF) materials, no official method exists to assess their nutrient release patterns. However, the increased production and distribution of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. Nonlinear regression was used to establish a correlation between the data generated from a 180-day soil incubation-column leaching procedure and 74 h accelerated lab extraction method, and to develop a model that can predict the 180-day nitrogen (N) release curve for a specific SRF and CRF product based on the data from the accelerated laboratory extraction method. Based on the R2 > 0.90 obtained for most materials, results indicated that the data generated from the 74 h accelerated lab extraction method could be used to predict N release from the selected materials during 180 days, including those fertilizers that require biological activity for N release. PMID:25051612

Medina, L Carolina; Sartain, Jerry; Obreza, Thomas; Hall, William L; Thiex, Nancy J

2014-01-01

92

Accelerating Ocean Energy to the Marketplace – Environmental Research at the U.S. Department of Energy National Laboratories  

SciTech Connect

The U.S. Department of Energy (US DOE) has mobilized its National Laboratories to address the broad range of environmental effects of ocean and river energy development. The National Laboratories are using a risk-based approach to set priorities among environmental effects, and to direct research activities. Case studies will be constructed to determine the most significant environmental effects of ocean energy harvest for tidal systems in temperate estuaries, for wave energy installations in temperate coastal areas, wave installations in sub-tropical waters, and riverine energy installations in large rivers. In addition, the National Laboratories are investigating the effects of energy removal from waves, tides and river currents using numerical modeling studies. Laboratory and field research is also underway to understand the effects of electromagnetic fields (EMF), acoustic noise, toxicity from anti-biofouling coatings, effects on benthic habitats, and physical interactions with tidal and wave devices on marine and freshwater organisms and ecosystems. Outreach and interactions with stakeholders allow the National Laboratories to understand and mitigate for use conflicts and to provide useful information for marine spatial planning at the national and regional level.

Copping, Andrea E.; Cada, G. F.; Roberts, Jesse; Bevelhimer, Mark

2010-10-06

93

Electron-Cloud Build-Up Simulations for the FNAL Main Injector  

SciTech Connect

We present a summary on ongoing simulation results for the electron-cloud (EC) buildup in the context of the proposed FNAL Main Injector (MI) intensity upgrade effort [1]. Most of the results presented here are for the field-free region at the location of the retarding field analyzer (RFA) electron detector [2-4]. The primary input variable we exercise is the peak secondary electron yield (SEY) {delta}{sub max}, which we let vary in the range 1.2 {le} {delta}{sub max} {le} 1.7. By combining our simulated results for the electron flux at the vacuum chamber wall with the corresponding RFA measurements we infer that 1.25 {approx}< {delta}{sub max} {approx}< 1.35 at this location. From this piece of information we estimate features of the EC distribution for various fill patterns, including the average electron number density n{sub e}. We then compare the behavior of the EC for a hypothetical RF frequency f{sub RF} = 212 MHz with the current 53 MHz for a given total beam population N{sub tot}. The density n{sub e} goes through a clear threshold as a function of N{sub tot} in a field-free region. As expected, the higher frequency leads to a weaker EC effect: the threshold in N{sub tot} is a factor {approx} 2 higher for f{sub RF} = 212 MHz than for 53 MHz, and ne is correspondingly lower by a factor {approx} 2 when N{sub tot} is above threshold. We briefly describe further work that needs to be carried out, sensitivities in the calculation, and puzzles in the results that remain to be addressed.

Furman, Miguel .A.

2008-08-25

94

SEY and Surface Analysis Measurements on FNAL Main Injector Ring S/S Beam Chamber Material  

SciTech Connect

Material was provided by Dr. Weiren Chou, FNAL. Both mildly-activated used, and new sections of stainless steel (type 316L) beam chamber were measured. Centimeter-sized coupons were cleanly dry-cut from the large flat surface (called ''flat side'' in the plots) and from the ID end (inside diameter of the ring, in the case of the used material) and narrow end (in the case of the new material). The unused material was ultra-soniced in acetone (to remove storage residue), then rinsed with ethanol and blown dry with filtered N{sub 2}-gas, to simulate new chamber installation final rinse. Used material was installed, as cut. Surface chemistry was measured using x-ray photoelectron spectroscopy (sometimes called ''ESCA''). With this technique, soft x-rays (1486 eV) illuminate the sample, penetrating into the surface ten microns. Photoelectrons are generated from energy levels of the constituent compounds/elements present. Those electrons, within 5 nm or so of the surface, escape without energy loss and preserve valence information about the atomic levels from which they were generated. An electron energy analyzer, of good energy resolution, measures the photoelectron energy, thereby yielding both valence (chemical) information and relative atomic abundances in the top 5 nm of surface. Using appropriate sensitivity factors, these intensities are converted to a semi-quantitative (surface atom %) concentration in the analyzed layer. As a benchmark, the limit for carbon contamination on vacuum components for UHV use at SLAC is 50 at%. That corresponds to about 8-10 monolayers of elemental carbon. XPS does not detect hydrogen because it has no electrons after bonding. Generally, hydrides do not show evidence of ''chemical shift'' of the binding energy of the metal lines.

Kirby, Robert E.; /SLAC

2006-09-18

95

Evaluation of a commercial system for CAMAC-based control of the Chalk River Laboratories tandem-accelerator-superconducting-cyclotron complexcomplex  

SciTech Connect

This paper discusses the control system of the Tandem Accelerator Superconducting Cyclotron (TASCC) of AECL Research at its Chalk River Laboratories which is presently based on a PDP-11 computer and the IAS operating system. The estimated expense of a custom conversion of the system to a current, equivalent operating system is prohibitive. The authors have evaluated a commercial control package from VISTA Control Systems based on VAX microcomputers and the VMS operating system. Vsystem offers a modern, graphical operator interface, an extensive software toolkit for configuration of the system and a multi-feature data-logging capability, all of which far surpass the functionality of the present control system. However, the implementation of some familiar, practical features that TASCC operators find to be essential has proven to be challenging. The assessment of Vsystem, which is described in terms of presently perceived strengths and weaknesses, is, on balance, very positive.

Greiner, B.F.; Caswell, D.J.; Slater, W.R. (TASCC Accelerators and Development, Nuclear Physics Branch, AECL Research, Chalk River Lab., Chalk River, Ontario K0J 1J0 (CA))

1992-04-01

96

Evaluation of automated RT-PCR to accelerate the laboratory diagnosis of foot-and-mouth disease virus.  

PubMed

Automated fluorogenic (5' nuclease probe-based) reverse transcription polymerase chain reaction (RT-PCR) procedures were evaluated for the diagnosis of foot-and-mouth disease (FMD) using suspensions of vesicular epithelium, heparinised or clotted blood, milk and oesophageal-pharyngeal fluid ('probang') samples from the United Kingdom (UK) 2001 epidemic and on sera from animals experimentally infected with the outbreak serotype O FMD virus strain. A MagNA Pure LC was initially programmed to automate the nucleic acid extraction and RT procedures with the PCR amplification carried out manually by fluorogenic assay in a GeneAmp 5700 Sequence Detection System. This allowed 32 samples to be tested by one person in a typical working day or 64 samples by two people within 10-12 h. The PCR amplification was later automated and a protocol developed for one person to complete a single test incorporating 96 RT-PCR results within 2 working days or for two people to do the same thing in around 12 h. The RT-PCR results were directly compared with those obtained by the routine diagnostic tests of ELISA and virus isolation in cell culture. The results on blood, probang and milk samples were in broad agreement between the three procedures but specific RT-PCR protocols for such material have to be fully optimised as perhaps have the positive-negative acceptance criteria. However, the automated RT-PCR achieved definitive diagnostic results (positive or negative) on supernatant fluids from first passage inoculated cell cultures and its sensitivity was greater than ELISA on suspensions of vesicular epithelium (ES) and at least equivalent to that of virus isolation in cell culture. The combined tests of ELISA, virus isolation in cell culture and RT-PCR might, therefore, only be required for confirmation of a first outbreak of FMD in a previously FMD-free country. Should a prolonged outbreak subsequently occur, then either ELISA plus RT-PCR or else RT-PCR alone could be used as the laboratory diagnostic tool(s). Either approach would eliminate the requirement for sample passage in cell culture and considerably advance the issue of laboratory diagnostic test results. PMID:12505626

Reid, Scott M; Grierson, Sylvia S; Ferris, Nigel P; Hutchings, Geoffrey H; Alexandersen, Soren

2003-02-01

97

Investigation of the effects of acid rain on the deterioration of cement concrete using accelerated tests established in laboratory  

NASA Astrophysics Data System (ADS)

Deterioration of cement concrete specimens caused by simulated acid rain was investigated by laboratory tests. Before and after cement concrete specimens were exposed to simulated acid rain, the neutralized depth, the compressive strength and the chemical compositions in the hardened cement paste were measured. The mineralogical composition of the concrete specimens was analyzed with XRD. The results lead to the following conclusions: the neutralized depth of the concrete specimens of all experiments can be described as a power function of exposure duration, CaO loss and the reduction rate of strength increased with H + and decreased with SO 42- concentration in simulated acid rain. The original mineral compounds such as [Na K]AlSi 3O 8 and [Ca Na][SiAl] 4O 8 in the hardened cement paste are converted to CaSO 4·2H 2O, CaAl 2Si 2O 8 and Ca 3Al 6O 12·CaSO 4. And these are larger in volume so that the reaction with SO 42- ions result in volume expansion and strength decrease. The reduction rate of strength has a binary linear relation to the CaO loss rate and the ratio of SO 3 content to CaO content in the hardened cement paste. So the deterioration of acid rain on the concrete specimen is caused by both H + dissolution and SO 42- expansion.

Xie, Shaodong; Qi, Li; Zhou, Ding

98

Calculation of Transactinide Homolog Isotope Production Reactions Possible with the Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory  

SciTech Connect

The LLNL heavy element group has been investigating the chemical properties of the heaviest elements over the past several years. The properties of the transactinides (elements with Z > 103) are often unknown due to their low production rates and short half-lives, which require lengthy cyclotron irradiations in order to make enough atoms for statistically significant evaluations of their chemistry. In addition, automated chemical methods are often required to perform consistent and rapid chemical separations on the order of minutes for the duration of the experiment, which can last from weeks to months. Separation methods can include extraction chromatography, liquid-liquid extraction, or gas-phase chromatography. Before a lengthy transactinide experiment can be performed at an accelerator, a large amount of preparatory work must be done both to ensure the successful application of the chosen chemical system to the transactinide chemistry problem being addressed, and to evaluate the behavior of the lighter elemental homologs in the same chemical system. Since transactinide chemistry is literally performed on one single atom, its chemical properties cannot be determined from bulk chemical matrices, but instead must be inferred from the behavior of the lighter elements that occur in its chemical group and in those of its neighboring elements. By first studying the lighter group homologs in a particular chemical system, when the same system is applied to the transactinide element under investigation, its decay properties can be directly compared to those of the homologues, thereby allowing an inference of its own chemistry. The Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory (LLNL) includes a 1 MV Tandem accelerator, capable of accelerating light ions such as protons to energies of roughly 15 MeV. By using the CAMS beamline, tracers of transactinide homolog elements can be produced both for development of chemical systems and for evaluation of homolog chemical properties. CAMS also offers an environment for testing these systems 'online' by incorporating automated chemical systems into the beamline so that tracers can be created, transported, and chemically separated all on the shorter timescales required for transactinide experiments. Even though CAMS is limited in the types and energies of ions they can accelerate, there are still a wide variety of reactions that can be performed there with commercially available target materials. The half-lives of these isotopes vary over a range that could be used for both online chemistry (where shorter half-lives are required) and benchtop tracers studies (where longer lived isotopes are preferred). In this document, they present a summary of tracer production reactions that could be performed at CAMS, specifically for online, automated chemical studies. They are from chemical groups four through seven, 13, and 14, which would be appropriate for studies of elements 104-107, 113, and 114. Reactions were selected that had (a) commercially available target material, (b) half-lives long enough for transport from a target chamber to an automated chemistry system, and (c) cross-sections at CAMS available projectile energies that were large enough to produce enough atoms to result in a statistically relevant signal after losses for transport and chemistry were considered. In addition, the resulting product atoms had to decay with an observable gamma-ray using standard Ge gamma-ray detectors. The table includes calculations performed for both metal targets and their corresponding oxides.

Moody, K J; Shaughnessy, D A; Gostic, J M

2011-11-29

99

Accelerator mass spectrometry of 63Ni at the Munich Tandem Laboratory for estimating fast neutron fluences from the Hiroshima atomic bomb.  

PubMed

After the release of the present dosimetry system DS86 in 1987, measurements have shown that DS86 may substantially underestimate thermal neutron fluences at large distances (>1,000 m) from the hypocenter in Hiroshima. This discrepancy casts doubts on the DS86 neutron source term and, consequently, the survivors' estimated neutron doses. However, the doses were caused mainly by fast neutrons. To determine retrospectively fast neutron fluences in Hiroshima, the reaction 63Cu(n, p)63Ni can be used, if adequate copper samples can be found. Measuring 63Ni (half life 100 y) in Hiroshima samples requires a very sensitive technique, such as accelerator mass spectrometry (AMS), because of the relatively small amounts of 63Ni expected (approximately 10(5)-10(6) atoms per gram of copper). Experiments performed at Lawrence Livermore National Laboratory have demonstrated in 1996 that AMS can be used to measure 63Ni in Hiroshima copper samples. Subsequently, a collaboration was established with the Technical University of Munich in view of its potential to perform more sensitive measurements of 63Ni than the Livermore facility and in the interest of interlaboratory validation. This paper presents the progress made at the Munich facility in the measurement of 63Ni by AMS. The Munich accelerator mass spectrometry facility is a combination of a high energy tandem accelerator and a detection system featuring a gas-filled magnet. It is designed for high sensitivity measurements of long-lived radioisotopes. Optimization of the ion source setup has further improved the sensitivity for 63Ni by reducing the background level of the 63Cu isobar interference by about two orders of magnitude. Current background levels correspond to a ratio of 63Ni/Ni<2x10(-14) and suggest that, with adequate copper samples, the assessment of fast neutron fluences in Hiroshima and Nagasaki is possible for ground distances of up to 1500 m, and--under favorable conditions--even beyond. To demonstrate this capability, we have measured successfully 6Ni/Ni ratios as low as (3.5 +/- 0.6) x 10(-13). The latter are, based on DS86, representative of a ratio expected from a typical Hiroshima copper sample at about 1,300-m ground range. PMID:11007457

Rühm, W; Knie, K; Rugel, G; Marchetti, A A; Faestermann, T; Wallner, C; McAninch, J E; Straume, T; Korschinek, G

2000-10-01

100

Accelerating the Whiteshell Laboratories Decommissioning Through the Implementation of a Projectized and Delivery-Focused Organization - 13074  

SciTech Connect

Whiteshell Laboratories (WL) is a nuclear research site in Canada that was commissioned in 1964 by Atomic Energy of Canada Limited. It covers a total area of approximately 4,375 hectares (10,800 acres) and includes the main campus site, the Waste Management Area (WMA) and outer areas of land identified as not used for or impacted by nuclear development or operations. The WL site employed up to 1100 staff. Site activities included the successful operation of a 60 MW organic liquid-cooled research reactor from 1965 to 1985, and various research programs including reactor safety research, small reactor development, fuel development, biophysics and radiation applications, as well as work under the Canadian Nuclear Fuel Waste Management Program. In 1997, AECL made a business decision to discontinue research programs and operations at WL, and obtained government concurrence in 1998. The Nuclear Legacy Liabilities Program (NLLP) was established in 2006 by the Canadian Government to remediate nuclear legacy liabilities in a safe and cost effective manner, including the WL site. The NLLP is being implemented by AECL under the governance of a Natural Resources Canada (NRCan)/AECL Joint Oversight Committee (JOC). Significant progress has since been made, and the WL site currently holds the only Canadian Nuclear Safety Commission (CNSC) nuclear research site decommissioning license in Canada. The current decommissioning license is in place until the end of 2018. The present schedule planned for main campus decommissioning is 30 years (to 2037), followed by institutional control of the WMA until a National plan is implemented for the long-term management of nuclear waste. There is an impetus to advance work and complete decommissioning sooner. To accomplish this, AECL has added significant resources, reorganized and moved to a projectized environment. This presentation outlines changes made to the organization, the tools implemented to foster projectization, and the benefits and positive impacts on schedule and delivery. A revised organizational structure was implemented in two phases, starting 2011 April 1, to align WL staff with the common goal of decommissioning the site through the direction of the WL Decommissioning Project General Manager. On 2011 September 1, the second phase of the reorganization was implemented and WL Decommissioning staff was organized under five Divisions: Programs and Regulatory Compliance, General Site Services, Decommissioning Strategic Planning, Nuclear Facilities and Project Delivery. A new Mission, Vision and Objectives were developed for the project, and several productivity enhancements are being implemented. These include the use of an integrated and fully re-sourced Site Wide Schedule that is updated and reviewed at Plan-of-the-Week meetings, improved work distribution throughout the year, eliminating scheduling 'push' mentality, project scoreboards, work planning implementation, lean practices and various process improvement initiatives. A revised Strategic Plan is under development that reflects the improved project delivery capabilities. As a result of these initiatives, and a culture change towards a projectized approach, the decommissioning schedule will be advanced by approximately 10 years. (authors)

Wilcox, Brian; Mellor, Russ; Michaluk, Craig [Atomic Energy of Canada Limited, Whiteshell Laboratories, Pinawa, Manitoba (Canada)] [Atomic Energy of Canada Limited, Whiteshell Laboratories, Pinawa, Manitoba (Canada)

2013-07-01

101

LBNL-1402E/CBP Tech Note 387 (14 Nov. 2008) Electron-Cloud Build-Up Simulations for the FNAL Main Injector  

E-print Network

in a parameter regime where other storage rings have seen a significant EC effect. Motivated by this concern Injector M. A. Furman, Center for Beam Physics, LBNL, Berkeley, CA 94720-8211, USA Abstract We present FNAL Main Injector (MI) intensity upgrade ef- fort [1]. Most of the results presented here

Furman, Miguel

102

US Particle Accelerators at Age 50.  

ERIC Educational Resources Information Center

Reviews the development of accelerators over the past 50 years. Topics include: types of accelerators, including cyclotrons; sociology of accelerators (motivation, financing, construction, and use); impact of war; national laboratories; funding; applications; future projects; foreign projects; and international collaborations. (JN)

Wilson, R. R.

1981-01-01

103

Optimization and validation of an accelerated laboratory extraction method to estimate nitrogen release patterns of slow- and controlled-release fertilizers.  

PubMed

Several technologies have been proposed to characterize the nutrient release and availability patterns of enhanced-efficiency fertilizers (EEFs), especially slow-release fertilizers (SRFs) and controlled-release fertilizers (CRFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize EEF materials, no validated method exists to assess their nutrient release patterns. However, the increased use of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. A series of experiments were conducted to evaluate the effect of temperature, fertilizer test portion size, and extraction time on the performance of a 74 h accelerated laboratory extraction method to measure SRF and CRF nutrient release profiles. Temperature was the only factor that influenced nutrient release rate, with a highly marked effect for phosphorus and to a lesser extent for nitrogen (N) and potassium. Based on the results, the optimal extraction temperature set was: Extraction No. 1-2:00 h at 25 degrees C; Extraction No. 2-2:00 h at 50 degrees C; Extraction No. 3-20:00 h at 55 degrees C; and Extraction No. 4-50:00 h at 60 degrees C. Ruggedness of the method was tested by evaluating the effect of small changes in seven selected factors on method behavior using a fractional multifactorial design. Overall, the method showed ruggedness for measuring N release rates of coated CRFs. PMID:25051611

Medina, L Carolina; Sartain, Jerry B; Obreza, Thomas A; Hall, William L; Thiex, Nancy J

2014-01-01

104

Creation mechanism of quantum accelerator modes Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics,  

E-print Network

Creation mechanism of quantum accelerator modes P. Ahmadi Department of Physics, MIT-Harvard Center investigate the creation mechanism of quantum accelerator modes which are attributed to the existence it is important to understand their creation mechanism. To this end two theoretical models have been developed

Summy, Gil

105

Linear Accelerators  

SciTech Connect

In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

Sidorin, Anatoly [Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna (Russian Federation)

2010-01-05

106

Studies of E-Cloud Build up for the FNAL Main Injector and for theLHC  

SciTech Connect

We present a summary of recent simulation studies of the electron-cloud (EC) build-up for the FNAL MI and for the LHC. In the first case we pay particular attention to the dependence on bunch intensity N{sub b} at injection energy assuming the nominal bunch spacing t{sub b} = 19 ns, and we focus on the dipole magnets and field-free regions. The saturated value of the average EC density shows a clear threshold in N{sub b} beyond which the beam will be approximately neutralized on average. For the case of the LHC we limit our discussion to arc dipoles at collision energy, and bunch spacings t{sub b} = 25 ns or t{sub b} = 75 ns. The main variables exercised in this study are N{sub b} and the peak value of the secondary emission yield (SEY) {delta}{sub max}. For t{sub b} = 25 ns we conclude that the EC power deposition is comfortably below the available cooling capacity of the cryogenic system if {delta}{sub max} is below {approx} 1.2 at nominal N{sub b}. For t{sub b} = 75 ns, the EC power deposition is insignificant. As a byproduct of this exercise, we reach a detailed understanding of the significant role played by the backscattered secondary electrons. This article summarizes the results, an slightly extends the discussions, presented in Refs. 1 and 2.

Furman, M.A.

2006-06-14

107

Overview of accelerators in medicine  

SciTech Connect

Accelerators used for medicine include synchrotrons, cyclotrons, betatrons, microtrons, and electron, proton, and light ion linacs. Some accelerators which were formerly found only at physics laboratories are now being considered for use in hospital-based treatment and diagnostic facilities. This paper presents typical operating parameters for medical accelerators and gives specific examples of clinical applications for each type of accelerator, with emphasis on recent developments in the field.

Lennox, A.J. [Fermi National Accelerator Lab., Batavia, IL (US)]|[Rush Univ., Chicago, IL (US)

1993-06-01

108

a Measurement of the Ratio of Neutral Current to Charged Current Deep Inelastic Muon Neutrino Scattering Interactions in a Fine-Grained Neutrino Detector at Fnal  

NASA Astrophysics Data System (ADS)

R_nu, the ratio of neutral current to charged current deep inelastic nu_mu-nucleon scattering interactions was measured in the Lab C fine-grained neutrino detector at the Fermi National Accelerator Laboratory. With a hadronic shower energy cut of 10 GeV, R_nu = 0.304 +/- 0.006. With a hadronic shower energy cut of 60 GeV, R_ nu = 0.304 +/- 0.008.

Perkins, George John

109

Mitigation Plans for the Microbunching-Instability-Related COTR at ASTA/FNAL  

SciTech Connect

At the Advanced Superconducting Test Accelerator (ASTA) now under construction at Fermilab, we anticipate the appearance of the microbunching instability related to the longitudinal space charge (LSC) impedances. With a photoinjector source and up to two chicane compressors planned, the conditions should result in the shift of some microbunched features into the visible light regime. The presence of longitudinal microstructures (microbunching) in the electron beam or the leading edge spikes can result in strong, spatially localized coherent enhancements of optical transition radiation (COTR) that mask the actual beam profile. Several efforts on mitigation of the effects in the diagnostics task have been identified. At ASTA we have designed the beam profiling stations to have mitigation features based on spectral filtering, scintillator choice, and the timing of the trigger to the digital camera's CCD chip. Since the COTR is more intense in the NIR than UV we have selectable bandpass filters centered at 420 nm which also overlap the spectral emissions of the LYSO:Ce scintillators. By delaying the CCD trigger timing of the integration window by 40-50 ns, we can reject the prompt OTR signal and integrate on the delayed scintillator light predominately. This combination of options should allow mitigation of COTR enhancements of order 100-1000 in the distribution.

Lumpkin, A. H.; Johnson, A. M.

2013-05-01

110

Acceleration in astrophysics  

SciTech Connect

The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

Colgate, S.A.

1993-12-31

111

Accelerator Experiments for Astrophysics  

E-print Network

Many recent discoveries in astrophysics involve phenomena that are highly complex. Carefully designed experiments, together with sophisticated computer simulations, are required to gain insights into the underlying physics. We show that particle accelerators are unique tools in this area of research, by providing precision calibration data and by creating extreme experimental conditions relevant for astrophysics. In this paper we discuss laboratory experiments that can be carried out at the Stanford Linear Accelerator Center and implications for astrophysics.

Johnny S. T. Ng

2003-10-22

112

Breakthrough: Fermilab Accelerator Technology  

SciTech Connect

There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

None

2012-04-23

113

Tethered gravity laboratories study  

NASA Technical Reports Server (NTRS)

The following subject areas are covered: (1) thermal control issues; (2) attitude control sybsystem; (3) configuration constraints; (4) payload; (5) acceleration requirements on Variable Gravity Laboratory (VGL); and (6) VGL configuration highlights.

Lucchetti, F.

1989-01-01

114

Tethered gravity laboratories study  

NASA Technical Reports Server (NTRS)

Variable Gravity Laboratory studies are discussed. The following subject areas are covered: (1) conceptual design and engineering analysis; (2) control strategies (fast crawling maneuvers, main perturbations and their effect upon the acceleration level); and (3) technology requirements.

Lucchetti, F.

1989-01-01

115

Diagnostics for induction accelerators  

SciTech Connect

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.

Fessenden, T.J.

1996-04-01

116

Android Acceleration  

NSDL National Science Digital Library

Students prepare for the associated activity in which they investigate acceleration by collecting acceleration vs. time data using the accelerometer of a sliding Android device. Based on the experimental set-up for the activity, students form hypotheses about the acceleration of the device. Students will investigate how the force on the device changes according to Newton's Second Law. Different types of acceleration, including average, instantaneous and constant acceleration, are introduced. Acceleration and force is described mathematically and in terms of processes and applications.

IMPART RET Program, College of Information Science & Technology,

117

Biomedical accelerator mass spectrometry  

NASA Astrophysics Data System (ADS)

Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

Freeman, Stewart P. H. T.; Vogel, John S.

1995-05-01

118

First charge breeding of a rare-isotope beam with the electron-beam ion trap of the ReA post-accelerator at the National Superconducting Cyclotron Laboratory  

NASA Astrophysics Data System (ADS)

An electron-beam ion trap (EBIT) charge breeder is being brought into operation at the National Superconducting Cyclotron Laboratory at Michigan State University. The EBIT is part of the ReA post-accelerator for reacceleration of rare isotopes, which are thermalized in a gas "stopping" cell after being produced at high energy by projectile fragmentation. The ReA EBIT has a distinctive design; it is characterized by a high-current electron gun and a two-field superconducting magnet to optimize the capture and charge-breeding efficiency of continuously injected singly charged ion beams. Following a brief overview of the reaccelerator system and the ReA EBIT, this paper presents the latest commissioning results, particularly, charge breeding and reacceleration of the highly charged rare isotopes, 76Ga24 +, 25 +.

Lapierre, A.; Schwarz, S.; Baumann, T. M.; Cooper, K.; Kittimanapun, K.; Rodriguez, A. J.; Sumithrarachchi, C.; Williams, S. J.; Wittmer, W.; Leitner, D.; Bollen, G.

2014-02-01

119

First charge breeding of a rare-isotope beam with the electron-beam ion trap of the ReA post-accelerator at the National Superconducting Cyclotron Laboratory.  

PubMed

An electron-beam ion trap (EBIT) charge breeder is being brought into operation at the National Superconducting Cyclotron Laboratory at Michigan State University. The EBIT is part of the ReA post-accelerator for reacceleration of rare isotopes, which are thermalized in a gas "stopping" cell after being produced at high energy by projectile fragmentation. The ReA EBIT has a distinctive design; it is characterized by a high-current electron gun and a two-field superconducting magnet to optimize the capture and charge-breeding efficiency of continuously injected singly charged ion beams. Following a brief overview of the reaccelerator system and the ReA EBIT, this paper presents the latest commissioning results, particularly, charge breeding and reacceleration of the highly charged rare isotopes, (76)Ga(24 +, 25 +). PMID:24593600

Lapierre, A; Schwarz, S; Baumann, T M; Cooper, K; Kittimanapun, K; Rodriguez, A J; Sumithrarachchi, C; Williams, S J; Wittmer, W; Leitner, D; Bollen, G

2014-02-01

120

An Independent Freshman Laboratory.  

ERIC Educational Resources Information Center

Describes a first-year laboratory course designed to fulfill laboratory objectives of reinforcing lecture material, teaching experimental methodology, developing hands-on skills, and imparting a sense of error. The course's six segments examine: digital electronics with students building a photogate timer; error analysis; linear accelerated

Spencer, C. D.; Seligmann, P. F.

1992-01-01

121

Plasma based charged-particle accelerators  

Microsoft Academic Search

Studies of charged-particle acceleration processes remain one of the most important areas of research in laboratory, space and astrophysical plasmas. In this paper, we present the underlying physics and the present status of high gradient and high energy plasma accelerators. We will focus on the acceleration of charged particles to relativistic energies by plasma waves that are created by intense

R Bingham; J T Mendonça; P K Shukla

2004-01-01

122

Rail accelerator research at Lewis Research Center  

NASA Technical Reports Server (NTRS)

A rail accelerator was chosen for study as an electromagnetic space propulsion device because of its simplicity and existing technology base. The results of a mission feasibility study using a large rail accelerator for direct launch of ton-size payloads from the Earth's surface to space, and the results of initial tests with a small, laboratory rail accelerator are presented. The laboratory rail accelerator has a bore of 3 by 3 mm and has accelerated 60 mg projectiles to velocities of 300 to 1000 m/s. Rail materials of Cu, W, and Mo were tested for efficiency and erosion rate.

Kerslake, W. R.; Cybyk, B. Z.

1982-01-01

123

Accelerator simulation of astrophysical processes  

NASA Technical Reports Server (NTRS)

Phenomena that involve accelerated ions in stellar processes that can be simulated with laboratory accelerators are described. Stellar evolutionary phases, such as the CNO cycle, have been partially explored with accelerators, up to the consumption of He by alpha particle radiative capture reactions. Further experimentation is indicated on reactions featuring N-13(p,gamma)O-14, O-15(alpha, gamma)Ne-19, and O-14(alpha,p)F-17. Accelerated beams interacting with thin foils produce reaction products that permit a determination of possible elemental abundances in stellar objects. Additionally, isotopic ratios observed in chondrites can be duplicated with accelerator beam interactions and thus constraints can be set on the conditions producing the meteorites. Data from isotopic fractionation from sputtering, i.e., blasting surface atoms from a material using a low energy ion beam, leads to possible models for processes occurring in supernova explosions. Finally, molecules can be synthesized with accelerators and compared with spectroscopic observations of stellar winds.

Tombrello, T. A.

1983-01-01

124

LINAC for ADS application - accelerator technologies  

SciTech Connect

Sifnificant high-current, high-intensity accelerator research and development have been done in the recent past in the US, centered primarily at Los Alamos National Laboratory. These efforts have included designs for the Accelerator Production of Tritium Project, Accelerator Transmutation of Waste, and Accelerator Driven Systems, as well as many others. This past work and some specific design principles that were developed to optimie linac designs for ADS and other high-intensity applications will be discussed briefly.

Garnett, Robert W [Los Alamos National Laboratory; Sheffreld, Richard L [Los Alamos National Laboratory

2009-01-01

125

Accelerated Degradation of Polymers  

NSDL National Science Digital Library

For this laboratory exercise, you will monitor changes in the visual appearance of the samples, chemical changes and molecular weight changes as a function of exposure condition. Analysis of the neat and degraded systems will be done using visual evaluation, FTIR analysis and GPC analysis. After in-class presentation, completion of hands-on laboratory experiment and review of the information provided, you should be able to: ⢠Confidently discuss the mechanism of breakdown for a polymeric material exposed to various environmental conditions. ⢠Prepare samples and record an accurate account of their preparation for use in an outdoor environment and in an accelerated weathering chamber (Q-sun).

Derosa, Rebecca L.

2008-09-26

126

MUON ACCELERATION IN FFAG RINGS , Katharinenstr. 17, Berlin, Germany  

E-print Network

MUON ACCELERATION IN FFAG RINGS E. Keil , Katharinenstr. 17, Berlin, Germany A.M. Sessler , Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Abstract Compared to muon acceleration in re-circulating lin- ear accelerators, considered earlier, muon acceleration in FFAG rings holds the promise of having

Keil, Eberhard

127

Acceleration switch  

DOEpatents

The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

Abbin, Jr., Joseph P. (Albuquerque, NM); Devaney, Howard F. (Cedar Crest, NM); Hake, Lewis W. (Albuquerque, NM)

1982-08-17

128

Podcast: Acceleration  

NSDL National Science Digital Library

The Podcast: Acceleration is a segment of the Force and Motion Short Course. The podcast is 2 minutes 13 seconds in duration. Presented by science experts and NSTA staff, the NSTA Online Short Courses are professional development opportunities de

2009-07-06

129

Angular Acceleration  

NSDL National Science Digital Library

The simulation of a rotating wheel below shows the relationship between angular position, angular velocity, and angular acceleration. Graphs of angular position and angular velocity as a function of time are shown.

Christian, Wolfgang; Belloni, Mario

2008-02-19

130

UCLA Neptune Facility for Advanced Accelerator Studies  

SciTech Connect

The Neptune Laboratory at UCLA is being used for exploring concepts useful for advanced accelerators. This facility hosts a TW-class CO2 laser system and a high-brightness photoinjector producing a 14 MeV electron beam. The goal for the laboratory is to carry out experiments on high-gradient acceleration of externally injected electrons in both laser-driven relativistic plasma waves and EM laser field in vacuum. Experiments on plasma beat-wave acceleration using a prebunched electron beam, a high-energy gain 10-{mu}m inverse free electron laser accelerator, longitudinal electron beam shaping and laser based light-sources are planned.

Tochitsky, Sergei Ya.; Clayton, Christopher E.; Marsh, Kenneth A.; Joshi, Chandrashekhar [Neptune Laboratory, Department of Electrical Engineering, University of California at Los Angeles, 405 Hilgard avenue, Los Angeles, CA 90095 (United States); Rosenzweig, James B.; Pellegrini, Claudio [Neptune Laboratory, Department of Physics, University of California at Los Angeles, 405 Hilgard avenue, Los Angeles, CA 90095 (United States)

2004-12-07

131

Imaging using accelerated heavy ions  

SciTech Connect

Several methods for imaging using accelerated heavy ion beams are being investigated at Lawrence Berkeley Laboratory. Using the HILAC (Heavy-Ion Linear Accelerator) as an injector, the Bevalac can accelerate fully stripped atomic nuclei from carbon (Z = 6) to krypton (Z = 34), and partly stripped ions up to uranium (Z = 92). Radiographic studies to date have been conducted with helium (from 184-inch cyclotron), carbon, oxygen, and neon beams. Useful ranges in tissue of 40 cm or more are available. To investigate the potential of heavy-ion projection radiography and computed tomography (CT), several methods and instrumentation have been studied.

Chu, W.T.

1982-05-01

132

Acceleration Environment of the International Space Station  

NASA Technical Reports Server (NTRS)

Measurement of the microgravity acceleration environment on the International Space Station has been accomplished by two accelerometer systems since 2001. The Microgravity Acceleration Measurement System records the quasi-steady microgravity environment, including the influences of aerodynamic drag, vehicle rotation, and venting effects. Measurement of the vibratory/transient regime, comprised of vehicle, crew, and equipment disturbances, has been accomplished by the Space Acceleration Measurement System-II. Until the arrival of the Columbus Orbital Facility and the Japanese Experiment Module, the location of these sensors, and therefore, the measurement of the microgravity acceleration environment, has been limited to within the United States Laboratory. Japanese Aerospace Exploration Agency has developed a vibratory acceleration measurement system called the Microgravity Measurement Apparatus which will be deployed within the Japanese Experiment Module to make distributed measurements of the Japanese Experiment Module's vibratory acceleration environment. Two Space Acceleration Measurement System sensors from the United States Laboratory will be re-deployed to support vibratory acceleration data measurement within the Columbus Orbital Facility. The additional measurement opportunities resulting from the arrival of these new laboratories allows Principal Investigators with facilities located in these International Space Station research laboratories to obtain microgravity acceleration data in support of their sensitive experiments. The Principal Investigator Microgravity Services project, at NASA Glenn Research Center, in Cleveland, Ohio, has supported acceleration measurement systems and the microgravity scientific community through the processing, characterization, distribution, and archival of the microgravity acceleration data obtained from the International Space Station acceleration measurement systems. This paper summarizes the PIMS capabilities available to the International Space Station scientific community, introduces plans for extending microgravity analysis results to the newly arrived scientific laboratories, and provides summary information for known microgravity environment disturbers.

McPherson, Kevin; Kelly, Eric; Keller, Jennifer

2009-01-01

133

BRIAN F. GERKE SLAC National Accelerator Laboratory  

E-print Network

Telescope proposal (1 night, 2009) Co-I and principal author of a series of successful Lick Observatory-I and principal author of a successful Keck Observatory proposal (2 nights, 2005) Honors and Fellowships: Block extended X-ray source catalogue", M.N.R.A.S, 399, 715 (2009). J. M. Comerford, R. L. Griffith, B. F. G

Wechsler, Risa H.

134

205:20130828.1126 Dust Accelerator Laboratory  

E-print Network

and theoretical investigations of dusty plasma and impact processes · The development of new instrument concepts for future in- situ dust and plasma measurements on the surface of, and in orbit around, the Moon, near earth asteroids, and the moons of Mars, Phobos and Deimos · An extensive education and community development

Mojzsis, Stephen J.

135

Saskatchewan Accelerator Laboratory University of Saskatchewan  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3. Building Fire Alarm often. This document outlines and explains procedures for operating this cryogenic target system under . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.9. Automatic Target Valve Cycling Circuit

Saskatchewan, University of

136

Laser Accelerators  

NASA Astrophysics Data System (ADS)

It is now a fact that focusing an intense ultra short laser pulse onto a gas jet or thin targets, generates energetic collimated electrons or ions forming ultra short beams of energies > 100 MeV. The different mechanisms to explain such laser accelerated electrons or ions will be discussed. Data obtained by recent experiments will be presented. We report the experiment planed to study laser accelerated ions and/or particles using picosecond and femtosecond high energy laser pulses focused to achieve intensities >1018 watts/cm2. The design of the interaction chamber and the choice of targets as well as the ultra fast detection techniques will be speculated. This source of accelerated ions having unique properties is expected to become an interesting tool for many fields in physics, chemistry and biology. It can enable advances of devices to be used in medicine.

El Nadi, Lotfia M.; Mansour, Mohy S.; Abdellatif, Galila; Reda, Mohamad Atef

2010-04-01

137

Acceleration Studies  

NASA Technical Reports Server (NTRS)

Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

Rogers, Melissa J. B.

1993-01-01

138

Plasma accelerator  

DOEpatents

There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

Wang, Zhehui (Los Alamos, NM); Barnes, Cris W. (Santa Fe, NM)

2002-01-01

139

Accelerated Achievement  

ERIC Educational Resources Information Center

This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

Ford, William J.

2010-01-01

140

Particle acceleration  

NASA Technical Reports Server (NTRS)

Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

1986-01-01

141

Advanced turbine\\/COâ pellet accelerator  

Microsoft Academic Search

An advanced turbine\\/COâ pellet accelerator is being evaluated as a depaint technology at Oak Ridge National Laboratory. The program, sponsored by Warner Robins Air Logistics Center, Robins Air Force Base, Georgia, has developed a robot-compatible apparatus that efficiently accelerates pellets of dry ice with a high-speed rotating wheel. In comparison to the more conventional compressed air sandblast pellet accelerators, the

C. A. Foster; P. W. Fisher

1994-01-01

142

Sabre, A 10-mv Linear Induction Accelerator  

Microsoft Academic Search

SABRE (Sandia Accelerator and Beam Research Experiment) is a 10-MV, 250-kA, 40-ns linear induction accelerator. It was designed to be used in positive polarity output. Positive polarity accelerators are important for application to Sandia's ICF (Inertial Confinement Fusion) and LMF (Laboratory Microfusion Facility) program efforts. SABRE was built to allow a more detailed study of pulsed power issues associated with

J. P. Corley; S. A. Alexander; P. J. Pankuch; C. E. Heath; D. L. Johnson; J. J. Ramirez; G. J. Denison

1991-01-01

143

A PORTABLE ACCELERATOR CONTROL TOOLKIT  

Microsoft Academic Search

In recent years, the expense of creating good control soft- ware has led to a number of collaborative efforts among laboratories to share this cost. The EPICS collaboration is a particularly successful example of this trend. More recently another collaborative effort has addressed the need for sophisticated high level software, including model driven accelerator controls. This work builds upon the

William A. Watson III

1998-01-01

144

Non-accelerator Particle Physics  

E-print Network

Non-accelerator Particle Physics and Neutrino Physics Research programs of: Prof. Martin that often connect particle physics with astrophysics and cosmology Some questions: - What particles of the neutrino? #12;The techniques: Laboratory experiments, in the style of particle physics · High energy

Wechsler, Risa H.

145

A linear accelerator bunch length monitor  

SciTech Connect

A monitor has been developed that provides an indication of the bunching efficiency of the Saskatchewan Accelerator Laboratory`s Linear Accelerator (Linac). By adjusting the prebuncher phase at the injector, a decrease in energy spread of 15% at the end of the linac was observed. With more rigorous optimization, it is believed that a reduction of 20% or greater in energy spread can be achieved.

Jessie, D.; Norum, E. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Saskatchewan Accelerator Lab.] [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Saskatchewan Accelerator Lab.

1996-06-01

146

Numerical Model of the DARHT Accelerating Cell  

Microsoft Academic Search

The DARHT-2 facility at Los Alamos National Laboratory accelerates a 2?sec electron beam using a series of inductive accelerating cells. The cell inductance is provided by large Metglas cores, which are driven by a pulse-forming network. The original cell design was susceptible to electrical breakdown near the outer radius of the cores. We developed a numerical model for the cell,

T. P. Hughes; T. C. Genoni; H. A. Davis; M. Kang; B. A. Prichard

2005-01-01

147

Black holes at accelerators.  

E-print Network

ar X iv :h ep -p h/ 05 11 12 8v 3 6 A pr 2 00 6 Black Holes at Accelerators Bryan Webber Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK In theories with large extra dimensions and TeV-scale gravity, black holes... dimensions. 1. INTRODUCTION One of the most surprising and exciting possibilities for new physics at future colliders is the production of microscopic black holes [1, 2], which can occur in theories with large extra dimensions1 [3]. String theory suggests a...

Webber, Bryan R

148

Compact accelerator  

DOEpatents

A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

Caporaso, George J. (Livermore, CA); Sampayan, Stephen E. (Manteca, CA); Kirbie, Hugh C. (Los Alamos, NM)

2007-02-06

149

European underground laboratories: An overview  

E-print Network

Underground laboratories are complementary to those where the research in fundamental physics is made using accelerators. This report focus on the logistic and on the background features of the most relevant laboratories in Europe, stressing also on the low background facilities available. In particular the report is focus on the laboratories involved in the new Europeean project ILIAS with the aim to support the European large infrastructures operating in the astroparticle physics area.

Lino Miramonti

2005-03-31

150

Accelerator mass spectrometry.  

PubMed

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. PMID:18470926

Hellborg, Ragnar; Skog, Göran

2008-01-01

151

TRACKING ACCELERATOR SETTINGS.  

SciTech Connect

Recording setting changes within an accelerator facility provides information that can be used to answer questions about when, why, and how changes were made to some accelerator system. This can be very useful during normal operations, but can also aid with security concerns and in detecting unusual software behavior. The Set History System (SHS) is a new client-server system developed at the Collider-Accelerator Department of Brookhaven National Laboratory to provide these capabilities. The SHS has been operational for over two years and currently stores about IOOK settings per day into a commercial database management system. The SHS system consists of a server written in Java, client tools written in both Java and C++, and a web interface for querying the database of setting changes. The design of the SHS focuses on performance, portability, and a minimal impact on database resources. In this paper, we present an overview of the system design along with benchmark results showing the performance and reliability of the SHS over the last year.

D OTTAVIO,T.; FU, W.; OTTAVIO, D.P.

2007-10-15

152

Accelerators and the Accelerator Community  

SciTech Connect

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.

Malamud, Ernest; Sessler, Andrew

2008-06-01

153

VLHC accelerator physics  

SciTech Connect

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

Michael Blaskiewicz et al.

2001-11-01

154

Overview of Acceleration for a Neutrino Factory J. S. Berga  

E-print Network

1 Overview of Acceleration for a Neutrino Factory J. S. Berga , S. A. Kahna , and R. B. Palmera a Brookhaven National Laboratory, Upton, NY, 11725 This paper is an overview of the acceleration issues, the choices of RF frequency, the injection and extraction for accelerator rings, and the cost considerations

Berg, J. Scott

155

Technology of magnetically driven accelerators  

SciTech Connect

The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability. 8 figs., 1 tab.

Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

1985-03-26

156

Technology of magnetically driven accelerators  

SciTech Connect

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

Brix, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

1985-10-01

157

Mass spectrometry with accelerators.  

PubMed

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 methods of isobar separation. These techniques are discussed in the latter part of the review. PMID:22031277

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

2011-01-01

158

FFAG ACCELERATOR PROTON DRIVER FOR NEUTRINO FACTORY.  

SciTech Connect

This paper is the summary of a conceptual study of a Proton Driver for Neutrino Factory based on the use of a Fixed-Field Alternating-Gradient (FFAG) Accelerator. The required proton energy range for an optimum neutrino production is 5 to 12 GeV. This can be accomplished with a group of three concentric rings each with 807 m circumference [1]. FFAG Accelerators [2] have the capability to accelerate charged particles over a large momentum range ({+-}30-50%) and the feature of constant bending and focusing fields. Particles can be accelerated very fast at the rate given by the accelerating field of RF cavities placed in proper locations between magnets. The performance of FFAG accelerators is to be placed between that of Super-Conducting Linear Accelerators (SCL), with which they share the fast acceleration rate, and Rapid-Cycling Synchrotrons (RCS), as they allow the beam to re-circulate over fewer revolutions. Brookhaven National Laboratory is involved in the study of feasibility of FFAG Accelerators to accelerate intense beams of protons in the GeV energy range for a variety of applications the most important of which is the Upgrade of the Alternating Gradient Synchrotron (AGS) with a new FFAG injector [3] accelerating from 400 MeV to 1.5 GeV. The ring would be housed in the AGS tunnel and has henceforth a circumference of 807 m.

RUGGIERO, A.

2005-06-21

159

Space Radiation Effects Laboratory  

NASA Technical Reports Server (NTRS)

The SREL User's Handbook is designed to provide information needed by those who plan experiments involving the accelerators at this laboratory. Thus the Handbook will contain information on the properties of the machines, the beam parameters, the facilities and services provided for experimenters, etc. This information will be brought up to date as new equipment is added and modifications accomplished. This Handbook is influenced by the many excellent models prepared at other accelerator laboratories. In particular, the CERN Synchrocyclotron User's Handbook (November 1967) is closely followed in some sections, since the SREL Synchrocyclotron is a duplicate of the CERN machine. We wish to thank Dr. E. G. Michaelis for permission to draw so heavily on his work, particularly in Section II of this Handbook. We hope that the Handbook will prove useful, and will welcome suggestions and criticism.

1969-01-01

160

2011 Dielectric Laser Acceleration Workshop (DLA2011)  

SciTech Connect

The first ICFA Mini-workshop on Dielectric Laser Accelerators was held on September 15-16, 2011 at SLAC National Accelerator Laboratory. We present the results of the Workshop, and discuss the main conclusions of the Accelerator Applications, Photonics, and Laser Technologies working groups. Over 50 participants from 4 countries participated, discussing the state of the art in photonic structures, laser science, and nanofabrication as it pertains to laser-driven particle acceleration in dielectric structures. Applications of this new and promising acceleration concept to discovery science and industrial, medical, and basic energy sciences were explored. The DLA community is presently focused on making demonstrations of high gradient acceleration and a compatible attosecond injector source - two critical steps towards realizing the potential of this technology.

Bermel, Peter; /MIT; Byer, Robert L.; /Stanford U., Phys. Dept.; Colby, Eric R.; /SLAC; Cowan, Benjamin M.; /Tech-X, Boulder; Dawson, Jay; /LLNL, Livermore; England, R.Joel; /SLAC; Noble, Robert J.; /SLAC; Qi, Ming-Hao; /Purdue U.; Yoder, Rodney B.; /Manhattanville Coll., Purchase

2012-04-17

161

The Gran Sasso Laboratory  

NASA Astrophysics Data System (ADS)

The Gran Sasso underground laboratory is one of the four national laboratories run by the INFN (Istituto Nazionale di Fisica Nucleare). It is located under the Gran Sasso massif, in central Italy, between the cities of L'Aquila and Teramo, 120 km far from Rome. It is the largest underground laboratory for astroparticle physics in the world and the most advanced in terms of complexity and completeness of its infrastructures. The scientific program at the Gran Sasso National Laboratories (Laboratori Nazionali del Gran Sasso, LNGS)is mainly focused on astroparticle, particle and nuclear physics. The laboratory presently hosts many experiments as well as R&D activities, including world-leading research in the fields of solar neutrinos, accelerator neutrinos (CNGS neutrino beam from CERN to Gran Sasso), dark matter, neutrinoless double-beta decay and nuclear cross-section of astrophysical interest. Associate sciences like earth physics, biology and fundamental physics complement the activities. The laboratory is operated as an international science facility and hosts experiments whose scientific merit is assessed by an international advisory Scientific Committee. A review of the main experiments carried out at LNGS will be given, together with the most recent and relevant scientific results achieved.

Votano, L.

2012-09-01

162

The Accelerating Universe  

SciTech Connect

From keV electrons in terrestrial aurorae to Ultra High Energy Cosmic Rays from unidentified "Zevatrons", the cosmos shows a plutocratic proclivity to concentrate energy in a tiny minority of suprathermal particles. The mechanisms involved can be traced back to the ideas of Faraday, Fermi and Alfvén though we are learning that the details are idiosyncratic to the many environments that we have observed and that much can be learned from comparing and contrasting particle acceleration in laboratory and diverse astronomical locations. It will be argued that new mechanisms are required to account for recent observations of galactic nuclei, pulsar wind nebulae and interplanetary, interstellar and intergalactic media and some candidates will be discussed.

Blandford, Roger [Stanford University

2013-05-15

163

APT accelerator. Topical report  

SciTech Connect

The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation`s stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century.

Lawrence, G.; Rusthoi, D. [comp.] [ed.

1995-03-01

164

Muon Collider Progress: Accelerators  

SciTech Connect

A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 × 10{sup 34} cm{sup –2}s{sup –1}. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance (“cooling”). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

Zisman, Michael S.

2011-09-10

165

Chemical Accelerators The phrase "chemical accelerators"  

E-print Network

Meetings Chemical Accelerators The phrase "chemical accelerators" is scarcely older than for one or two dozen people grew to include nearly a hundred. Chemical accelerators is a name sug- gested by one of us for devices that produce beams of chemically interesting species at relative kinetic

Zare, Richard N.

166

ISIS upgrades David Findlay  

E-print Network

ISIS upgrades David Findlay Head, Accelerator Division ISIS Department Rutherford Appleton Laboratory / STFC Proton Accelerators for Science and Innovation, 12­14 January 2012, FNAL #12;2 ISIS World for research in the physical and life sciences National and international community of >2000 scientists -- ISIS

McDonald, Kirk

167

The Accelerator Test Facility at Brookhaven: Main capabilities  

NASA Astrophysics Data System (ADS)

Brookhaven National Laboratory's (BNL's) Accelerator Test Facility (ATF) is a user facility for accelerator- and beam- physics. Researchers from national and foreign universities, the DOE's national laboratories, and small businesses can carry out their experiments here, thereby relieving their institutions and companies from the large investment in accelerators, lasers, control and diagnostic equipment, and trained accelerator operators, all of which BNL's ATF offers. The main emphasis of this paper is on the capabilities of the ATF that I illustrate by discussing a few experiments. More detailed information can be obtained from the ATF web site: http://www.bnl.gov/atf.

Yakimenko, Vitaly

2004-12-01

168

Fifty years of accelerator based physics at Chalk River  

SciTech Connect

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

McKay, John W. [P.O. Box 463, Deep River, Ontario, K0J 1P0 (Canada)

1999-04-26

169

Language Laboratories.  

ERIC Educational Resources Information Center

This history of the language laboratory and the factors influencing its growth are briefly traced. Materials and equipment are described, and the problems involved in a laboratory operation are indicated. Also considered is the use of the language laboratory as a teaching machine and as a research device for education in general. A bibliography…

Mathieu, Gustave

1962-01-01

170

The Spallation Neutron Source accelerator system design  

NASA Astrophysics Data System (ADS)

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

Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O'Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

2014-11-01

171

Lessons from the Bevatron Accelerator Demolition - 12191  

SciTech Connect

The Bevatron accelerator at Lawrence Berkeley National Laboratory is the first DOE accelerator to be demolished. While there are many lessons learned from its demolition, this paper focuses on the following lessons learned that may be useful for other D and D projects: bounding project scope to ensure success, hazards mapping for focused characterization and remediation, establishing radiological evaluation criteria, and forecasting activation products. With D and D of many DOE accelerators likely to occur in the near future, these lessons learned should be considered in planning those projects. These lessons learned are likely to be applicable to other D and D projects as well. (authors)

Harkins, Joseph [Lawrence Berkeley National Laboratory, Berkeley, California, 94720 (United States); Cronin, Robert [CH2M HILL, Englewood, Colorado, 80112 (United States)

2012-07-01

172

Covariant Uniform Acceleration  

E-print Network

We show that standard Relativistic Dynamics Equation F=dp/d\\tau is only partially covariant. To achieve full Lorentz covariance, we replace the four-force F by a rank 2 antisymmetric tensor acting on the four-velocity. By taking this tensor to be constant, we obtain a covariant definition of uniformly accelerated motion. We compute explicit solutions for uniformly accelerated motion which are divided into four types: null, linear, rotational, and general. For null acceleration, the worldline is cubic in the time. Linear acceleration covariantly extends 1D hyperbolic motion, while rotational acceleration covariantly extends pure rotational motion. We use Generalized Fermi-Walker transport to construct a uniformly accelerated family of inertial frames which are instantaneously comoving to a uniformly accelerated observer. We explain the connection between our approach and that of Mashhoon. We show that our solutions of uniformly accelerated motion have constant acceleration in the comoving frame. Assuming the Weak Hypothesis of Locality, we obtain local spacetime transformations from a uniformly accelerated frame K' to an inertial frame K. The spacetime transformations between two uniformly accelerated frames with the same acceleration are Lorentz. We compute the metric at an arbitrary point of a uniformly accelerated frame. We obtain velocity and acceleration transformations from a uniformly accelerated system K' to an inertial frame K. We derive the general formula for the time dilation between accelerated clocks. We obtain a formula for the angular velocity of a uniformly accelerated object. Every rest point of K' is uniformly accelerated, and its acceleration is a function of the observer's acceleration and its position. We obtain an interpretation of the Lorentz-Abraham-Dirac equation as an acceleration transformation from K' to K.

Yaakov Friedman; Tzvi Scarr

2011-05-03

173

I. ACCELERATION A. Introduction  

E-print Network

I. ACCELERATION A. Introduction Following cooling and initial bunch compression, the beams must be rapidly accelerated. The acceleration needed for a Higgs collider is probably the most conventional part undertaken. A sequence of linacs would work, but would be expensive. Some form of circulating acceleration

McDonald, Kirk

174

Laboratory microfusion capability study  

NASA Astrophysics Data System (ADS)

The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility; and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options: the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase 2 study are described in the present report.

1993-05-01

175

Laboratory microfusion capability study  

SciTech Connect

The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options; the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase II study are described in the present report.

Not Available

1993-05-01

176

Acceleration without Horizons  

E-print Network

We derive the metric of an accelerating observer moving with non-constant proper acceleration in flat spacetime. With the exception of a limiting case representing a Rindler observer, there are no horizons. In our solution, observers can accelerate to any desired terminal speed $v_{\\infty} accelerating observer is completely determined by the distance of closest approach and terminal velocity or, equivalently, by an acceleration parameter and terminal velocity.

Alaric Doria; Gerardo Munoz

2015-02-18

177

Acceleration without Horizons  

E-print Network

We derive the metric of an accelerating observer moving with non-constant proper acceleration in flat spacetime. With the exception of a limiting case representing a Rindler observer, there are no horizons. In our solution, observers can accelerate to any desired terminal speed $v_{\\infty} accelerating observer is completely determined by the distance of closest approach and terminal velocity or, equivalently, by an acceleration parameter and terminal velocity.

Doria, Alaric

2015-01-01

178

Analysis of multilayer insulation between 80K and 300K  

SciTech Connect

A model has been developed that can be used to determine the temperature distribution and heat transfer through a multilayer insulation (MLI) blanket. Predictions from the model were compared with a series of temperature measurements made during laboratory experiments and during a test of five superconducting magnets (dipoles) installed in a string and tested at Fermi National Accelerator Laboratory, FNAL (ER Test).

Augustynowicz, S.D.; Demko, J.A. [Superconducting Super Collider Lab., Dallas, TX (United States); Datskov, V.I. [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of High Energy

1993-07-01

179

Accelerator Operators and Software Development  

SciTech Connect

At Thomas Jefferson National Accelerator Facility, accelerator operators perform tasks in their areas of specialization in addition to their machine operations duties. One crucial area in which operators contribute is software development. Operators with programming skills are uniquely qualified to develop certain controls applications because of their expertise in the day-to-day operation of the accelerator. Jefferson Lab is one of the few laboratories that utilizes the skills and knowledge of operators to create software that enhances machine operations. Through the programs written; by operators, Jefferson Lab has improved machine efficiency and beam availability. Because many of these applications involve automation of procedures and need graphical user interfaces, the scripting language Tcl and the Tk toolkit have been adopted. In addition to automation, some operator-developed applications are used for information distribution. For this purpose, several standard web development tools such as perl, VBScript, and ASP are used. Examples of applications written by operators include injector steering, spin angle changes, system status reports, magnet cycling routines, and quantum efficiency measurements. This paper summarizes how the unique knowledge of accelerator operators has contributed to the success of the Jefferson Lab control system. *This work was supported by the U.S. DOE contract No. DE-AC05-84-ER40150.

April Miller; Michele Joyce

2001-11-01

180

Minimum recommended SSC Laboratory seismic design requirements  

Microsoft Academic Search

The Superconducting Super Collider (SSC) Laboratory has been strategically located in Ellis County, Texas where design, construction, operation, and maintenance costs would be minimized. One of the parameters that affects costs during the design and construction phases of the laboratory life-cycle is the geological stability of the area with respect to seismic ground motion. Historical records demonstrate that bedrock accelerations

M. Butalla

1993-01-01

181

Advanced modeling of high intensity accelerators  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goals of this project were three-fold: (1) to develop a new capability, based on high performance (parallel) computers, to perform large scale simulations of high intensity accelerators; (2) to apply this capability to modeling high intensity accelerators under design at LANL; and (3) to use this new capability to improve the understanding of the physics of intense charge particle beams, especially in regard to the issue of beam halo formation. All of these goals were met. In particular, the authors introduced split-operator methods as a powerful and efficient means to simulate intense beams in the presence of rapidly varying accelerating and focusing fields. They then applied these methods to develop scaleable, parallel beam dynamics codes for modeling intense beams in linacs, and in the process they implemented a new three-dimensional space charge algorithm. They also used the codes to study a number of beam dynamics issues related to the Accelerator Production of Tritium (APT) project, and in the process performed the largest simulations to date for any accelerator design project. Finally, they used the new modeling capability to provide direction and validation to beam physics studies, helping to identify beam mismatch as a major source of halo formation in high intensity accelerators. This LDRD project ultimately benefited not only LANL but also the US accelerator community since, by promoting expertise in high performance computing and advancing the state-of-the-art in accelerator simulation, its accomplishments helped lead to approval of a new DOE Grand Challenge in Computational Accelerator Physics.

Ryne, R.D.; Habib, S.; Wangler, T.P.

1998-11-01

182

Federal laboratories for the 21st century  

SciTech Connect

Federal laboratories have successfully filled many roles for the public; however, as the 21st Century nears it is time to rethink and reevaluate how Federal laboratories can better support the public and identify new roles for this class of publicly-owned institutions. The productivity of the Federal laboratory system can be increased by making use of public outcome metrics, by benchmarking laboratories, by deploying innovative new governance models, by partnerships of Federal laboratories with universities and companies, and by accelerating the transition of federal laboratories and the agencies that own them into learning organizations. The authors must learn how government-owned laboratories in other countries serve their public. Taiwan`s government laboratory, Industrial Technology Research Institute, has been particularly successful in promoting economic growth. It is time to stop operating Federal laboratories as monopoly institutions; therefore, competition between Federal laboratories must be promoted. Additionally, Federal laboratories capable of addressing emerging 21st century public problems must be identified and given the challenge of serving the public in innovative new ways. Increased investment in case studies of particular programs at Federal laboratories and research on the public utility of a system of Federal laboratories could lead to increased productivity of laboratories. Elimination of risk-averse Federal laboratory and agency bureaucracies would also have dramatic impact on the productivity of the Federal laboratory system. Appropriately used, the US Federal laboratory system offers the US an innovative advantage over other nations.

Gover, J. [Sandia National Labs., Albuquerque, NM (United States); Huray, P.G. [Univ. of South Carolina, Columbia, SC (United States)

1998-04-01

183

Archimedes: Accelerator Reveals Ancient Text  

SciTech Connect

Archimedes (287-212 BC), who is famous for shouting 'Eureka' (I found it) is considered one of the most brilliant thinkers of all times. The 10th-century parchment document known as the 'Archimedes Palimpsest' is the unique source for two of the great Greek's treatises. Some of the writings, hidden under gold forgeries, have recently been revealed at the Stanford Synchrotron Radiation Laboratory at SLAC. An intense x-ray beam produced in a particle accelerator causes the iron in original ink, which has been partly erased and covered, to send out a fluorescence glow. A detector records the signal and a digital image showing the ancient writings is produced. Please join us in this fascinating journey of a 1,000-year-old parchment from its origin in the Mediterranean city of Constantinople to a particle accelerator in Menlo Park.

Bergmann, Uwe

2004-02-24

184

Accelerated leach test development program  

SciTech Connect

In FY 1989, a draft accelerated leach test for solidified waste was written. Combined test conditions that accelerate leaching were validated through experimental and modeling efforts. A computer program was developed that calculates test results and models leaching mechanisms. This program allows the user to determine if diffusion controls leaching and, if this is the case, to make projections of releases. Leaching mechanisms other than diffusion (diffusion plus source term partitioning and solubility limited leaching) are included in the program is indicators of other processes that may control leaching. Leach test data are presented and modeling results are discussed for laboratory scale waste forms composed of portland cement containing sodium sulfate salt, portland cement containing incinerator ash, and vinyl ester-styrene containing sodium sulfate. 16 refs., 38 figs., 5 tabs.

Fuhrmann, M.; Pietrzak, R.F.; Heiser, J.; Franz, E.M.; Colombo, P.

1990-11-01

185

Accelerator and Fusion Research Division 1989 summary of activities  

SciTech Connect

This report discusses the research being conducted at Lawrence Berkeley Laboratory's Accelerator and Fusion Research Division. The main topics covered are: heavy-ion fusion accelerator research; magnetic fusion energy; advanced light source; center for x-ray optics; exploratory studies; high-energy physics technology; and bevalac operations.

Not Available

1990-06-01

186

Ion accelerator applications in medicine and cultural heritage  

Microsoft Academic Search

Formerly, accelerator laboratories were mainly dedicated to nuclear physics. Today, they are used in up-coming research fields and applications like material analysis and material science as well as biology, medicine or archaeology. Practical applications have been developed, involving hospitals, industry and even humanists in the use of accelerators. This paper focuses on some medical and analytical applications of the HMI

A. Denker; D. Cordini; J. Heufelder; H. Homeyer; H. Kluge; I. Simiantonakis; R. Stark; A. Weber

2007-01-01

187

Accelerator experiments contradicting general relativity  

E-print Network

The deflection of gamma-rays in Earth's gravitational field is tested in laser Compton scattering at high energy accelerators. Within a formalism connecting the bending angle to the photon's momentum it follows that detected gamma-ray spectra are inconsistent with a deflection magnitude of 2.78 nrad, predicted by Einstein's gravity theory. Moreover, preliminary results for 13-28 GeV photons from two different laboratories show opposite - away from the Earth - deflection, amounting to 33.8-0.8 prad. I conclude that general relativity, which describes gravity at low energies precisely, break down at high energies.

Vahagn Gharibyan

2014-07-12

188

Industrialization of Superconducting RF Accelerator Technology  

NASA Astrophysics Data System (ADS)

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

Peiniger, Michael; Pekeler, Michael; Vogel, Hanspeter

2012-01-01

189

Improved plasma accelerator  

NASA Technical Reports Server (NTRS)

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.

Cheng, D. Y.

1971-01-01

190

Radio-frequency quadrupole linear accelerator  

SciTech Connect

The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented.

Wangler, T.P.; Stokes, R.H.

1980-01-01

191

Physics Classroom: The Acceleration of Gravity  

NSDL National Science Digital Library

This tutorial introduces the concept of gravitational acceleration. This tutorial explains the notation, numerical value, and how the numerical value of the gravitational acceleration is obtained. This tutorial includes two widgets: one where one can see the strength of the acceleration of gravity from any location on Earth, and another one where one can see a comparison of the acceleration of gravity of planets in our solar system to everyday objects, and to other objects in the solar system. The tutorial also includes a pictorial example, along with the widgets, along with links to tutorials to other general Physics concepts, simulations, and student activities. This is part of The Physics Classroom. This web site also includes interactive tools to help students with concepts and problem solving, worksheets for student assignments, and recommendations for simple introductory laboratories.

Henderson, Tom

2012-04-28

192

Pulsars and Acceleration Sites  

NASA Technical Reports Server (NTRS)

Rotation-powered pulsars are excellent laboratories for the studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. But even forty years after their discovery, we still do not understand their pulsed emission at any wavelength. I will review both the basic physics of pulsars as well as the latest developments in understanding their high-energy emission. Special and general relativistic effects play important roles in pulsar emission, from inertial frame-dragging near the stellar surface to aberration, time-of-flight and retardation of the magnetic field near the light cylinder. Understanding how these effects determine what we observe at different wavelengths is critical to unraveling the emission physics. Fortunately the Gamma-Ray Large Area Space Telescope (GLAST), with launch in May 2008 will detect many new gamma-ray pulsars and test the predictions of these models with unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 300 GeV.

Harding, Alice

2008-01-01

193

A Solid state accelerator  

SciTech Connect

We present a solid state accelerator concept utilizing particle acceleration along crystal channels by longitudinal electron plasma waves in a metal. Acceleration gradients of order 100 GV/cm are theoretically possible, but channeling radiation limits the maximum attainable energy to 10/sup 5/ TeV for protons. Beam dechanneling due to multiple scattering is substantially reduced by the high acceleration gradient. Plasma wave dissipation and generation in metals are also discussed.

Chen, P.; Noble, R.J.

1986-11-06

194

Paleomagnetics Laboratory  

NSDL National Science Digital Library

At this website, the California Institute of Technology's Paleomagnetics Laboratory promotes its research of weakly magnetic geologic and biological materials. Users can learn about the facilities such as the biomagnetics lab and the automatic sampler. The website features the laboratory's recent research on many topics including extraterrestrial magnetism, magnetofossils, and historical geomagnetic field behavior. Visitors can find out more about the many laboratory members' research activities through links to their home pages. Researchers can download a selection of the group's publications. Everyone can enjoy the amazing images from recent geologic field trips across the globe.

195

Acceleration-Induced Nonlocality  

E-print Network

The standard relativistic theory of accelerated reference frames in Minkowski spacetime is described. The measurements of accelerated observers are considered and the limitations of the standard theory, based on the hypothesis of locality, are pointed out. The physical principles of the nonlocal theory of accelerated observers are presented. The implications of the nonlocal theory are briefly discussed.

Bahram Mashhoon

2003-01-17

196

Acceleration: It's Elementary  

ERIC Educational Resources Information Center

Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

Willis, Mariam

2012-01-01

197

Direction of Acceleration  

NSDL National Science Digital Library

In this short lab, students observe the movement of an air bubble in a small level, attached to a toy truck, as it is moved from a stop, to a steady speed and back to a stop. This gives a visual to the concepts positive acceleration, zero acceleration and negative acceleration.

Mary Spaulding, Clearbrook-Gonvick Public School, Clearbrook Minnesota, based on an original activity from Physics Principles and Problems (1995) page 75.

198

Force, mass and acceleration  

Microsoft Academic Search

Force, mass and acceleration are everyday words but often used inaccurately. Force is a physical influence, which when applied to an object causes it to accelerate in the direction from which it was applied. Mass is the amount of matter in an object and is expressed in kilograms. Acceleration is the rate of change of velocity of an object in

Phil Dalrymple; Richard Griffiths

2005-01-01

199

Angular Acceleration without Torque?  

ERIC Educational Resources Information Center

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.

Kaufman, Richard D.

2012-01-01

200

Accelerating Research with  

E-print Network

Accelerating Academic Research with Cloud Computing Published: September 2014 For the latest information, please see www.microsoft.com/education #12;Accelerating Academic Research with Cloud Computing............................................................................................................................................................11 #12;1 Accelerating Academic Research with Cloud Computing Overview Universities today face

Bernstein, Phil

201

ADVANCED ULTRAFINE PARTICLE ACCELERATOR  

Microsoft Academic Search

The conceptual design of an Ultrafine Particle Radio Frequency Quadrupole (UFP-RFQ) accelerator is discussed. The results indicate that it is possible to accelerate 1 pm radius Al particles to velocities around 100 km\\/s in 100 m RFQ length. This accelerator can provide variable output particle velocity, with capability of handling different particle materials with different sizes. There are scientific, industrial

D. A. Swenson; A. E. Dabiri; Z. Mikic; D. B. McCall; M. F. Scharff

202

Laser guiding for GeV laser-plasma accelerators.  

PubMed

Guiding of relativistically intense laser beams in preformed plasma channels is discussed for development of GeV-class laser accelerators. Experiments using a channel guided laser wakefield accelerator at Lawrence Berkeley National Laboratory (LBNL) have demonstrated that near mono-energetic 100 MeV-class electron beams can be produced with a 10 TW laser system. Analysis, aided by particle-in-cell simulations, as well as experiments with various plasma lengths and densities, indicate that tailoring the length of the accelerator, together with loading of the accelerating structure with beam, is the key to production of mono-energetic electron beams. Increasing the energy towards a GeV and beyond will require reducing the plasma density and design criteria are discussed for an optimized accelerator module. The current progress and future directions are summarized through comparison with conventional accelerators, highlighting the unique short-term prospects for intense radiation sources based on laser-driven plasma accelerators. PMID:16483950

Leemans, Wim; Esarey, Eric; Geddes, Cameron; Schroeder, Carl; Tóth, Csaba

2006-03-15

203

Accelerators for Inertial Fusion Energy Production  

NASA Astrophysics Data System (ADS)

Since the 1970s, high energy heavy ion accelerators have been one of the leading options for imploding and igniting targets for inertial fusion energy production. Following the energy crisis of the early 1970s, a number of people in the international accelerator community enthusiastically began working on accelerators for this application. In the last decade, there has also been significant interest in using accelerators to study high energy density physics (HEDP). Nevertheless, research on heavy ion accelerators for fusion has proceeded slowly pending demonstration of target ignition using the National Ignition Facility (NIF), a laser-based facility at Lawrence Livermore National Laboratory. A recent report of the National Research Council recommends expansion of accelerator research in the US if and when the NIF achieves ignition. Fusion target physics and the economics of commercial energy production place constraints on the design of accelerators for fusion applications. From a scientific standpoint, phase space and space charge considerations lead to the most stringent constraints. Meeting these constraints almost certainly requires the use of multiple beams of heavy ions with kinetic energies > 1 GeV. These constraints also favor the use of singly charged ions. This article discusses the constraints for both fusion and HEDP, and explains how they lead to the requirements on beam parameters. RF and induction linacs are currently the leading contenders for fusion applications. We discuss the advantages and disadvantages of both options. We also discuss the principal issues that must yet be resolved.

Bangerter, R. O.; Faltens, A.; Seidl, P. A.

2014-02-01

204

Hydromechanics Laboratory  

Microsoft Academic Search

The Hydromechanics Laboratory supports midshipmen education, as well as midshipmen, faculty and staff research, in the areas of naval architecture and ocean engineering. The laboratory facilities include a large towing tank (380-ft long, 26- ft wide, and 16-ft deep), a small towing tank (120-ft long, 8-ft wide, and 5-ft deep), a coastal engineering wave basin (52-ft long, 48-ft wide, and

David L. Kriebel

205

Entanglement of Accelerating Particles  

E-print Network

We study how the entanglement of a maximally entangled pair of particles is affected when one or both of the pair are uniformly accelerated, while the detector remains in an inertial frame. We find that the entanglement is unchanged if all degrees of freedom are considered. However, particle pairs are produced, and the entanglements of different bipartite systems may change with the acceleration. In particular, the entanglement between accelerating fermions is transferred preferentially to the produced antiparticles when the acceleration is large, and the entanglement transfer is complete when the acceleration approaches infinity. However, for scalar particles, no entanglement transfer to the antiparticles is observed.

W. L. Ku; M. -C. Chu

2007-09-03

206

High brightness electron accelerator  

DOEpatents

A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating 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 electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

Sheffield, Richard L. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM); Young, Lloyd M. (Los Alamos, NM)

1994-01-01

207

Atomic Molecular and Optical Physics Laboratory Toshiyuki Azuma Division of Genomic Technologies (Center for Life Science Technologies) Piero Carninci  

E-print Network

Radioactive Isotope Physics Laboratory (Nishina Center for Accelerator-Based Science) Hiroyoshi SakuraiAtomic Molecular and Optical Physics Laboratory Toshiyuki Azuma Division of Genomic Technologies (Center for Life Science Technologies) Piero Carninci Computational Astrophysics Laboratory Toshikazu

Fukai, Tomoki

208

Atomic Molecular and Optical Physics Laboratory Toshiyuki Azuma Division of Genomic Technologies (Center for Life Science Technologies) Piero Carninci  

E-print Network

Laboratory Atsushi Mochizuki Strong Correlation Physics Division (Center for Emergent Matter Science) Naoto Physics Laboratory (Nishina Center for Accelerator-Based Science) Hiroyoshi Sakurai Cellular MemoryAtomic Molecular and Optical Physics Laboratory Toshiyuki Azuma Division of Genomic Technologies

Fukai, Tomoki

209

Laboratory directed research and development  

SciTech Connect

The purposes of Argonne's Laboratory Directed Research and Development (LDRD) Program are to encourage the development of novel concepts, enhance the Laboratory's R D capabilities, and further the development of its strategic initiatives. Among the aims of the projects supported by the Program are establishment of engineering proof-of-principle''; development of an instrumental prototype, method, or system; or discovery in fundamental science. Several of these project are closely associated with major strategic thrusts of the Laboratory as described in Argonne's Five Year Institutional Plan, although the scientific implications of the achieved results extend well beyond Laboratory plans and objectives. The projects supported by the Program are distributed across the major programmatic areas at Argonne. Areas of emphasis are (1) advanced accelerator and detector technology, (2) x-ray techniques in biological and physical sciences, (3) advanced reactor technology, (4) materials science, computational science, biological sciences and environmental sciences. Individual reports summarizing the purpose, approach, and results of projects are presented.

Not Available

1991-11-15

210

Cryogenic Technology for Superconducting Accelerators  

NASA Astrophysics Data System (ADS)

Superconducting devices such as magnets and cavities are key components in the accelerator field for increasing the beam energy and intensity, and at the same time making the system compact and saving on power consumption in operation. An effective cryogenic system is required to cool and keep the superconducting devices in the superconducting state stably and economically. The helium refrigeration system for application to accelerators will be discussed in this review article. The concept of two cooling modes -- the liquefier and refrigerator modes -- will be discussed in detail because of its importance for realizing efficient cooling and stable operation of the system. As an example of the practical cryogenic system, the TRISTAN cryogenic system of KEK Laboratory will be treated in detail and the main components of the cryogenic system, including the high-performance multichannel transfer line and liquid nitrogen circulation system at 80K, will also be discussed. In addition, we will discuss the operation of the cryogenic system, including the quench control and safety of the system. The satellite refrigeration system will be discussed because of its potential for wide application in medium-size accelerators and in industry.

Hosoyama, Kenji

2012-01-01

211

Compensation Techniques in Accelerator Physics  

SciTech Connect

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

Hisham Kamal Sayed

2011-05-31

212

Self-accelerating Warped Braneworlds  

SciTech Connect

Braneworld models with induced gravity have the potential to replace dark energy as the explanation for the current accelerating expansion of the Universe. The original model of Dvali, Gabadadze and Porrati (DGP) demonstrated the existence of a ''self-accelerating'' branch of background solutions, but suffered from the presence of ghosts. We present a new large class of braneworld models which generalize the DGP model. Our models have negative curvature in the bulk, allow a second brane, and have general brane tensions and localized curvature terms. We exhibit three different kinds of ghosts, associated to the graviton zero mode, the radion, and the longitudinal components of massive graviton modes. The latter two species occur in the DGP model, for negative and positive brane tension respectively. In our models, we find that the two kinds of DGP ghosts are tightly correlated with each other, but are not always linked to the feature of self-acceleration. Our models are a promising laboratory for understanding the origins and physical meaning of braneworld ghosts, and perhaps for eliminating them altogether.

Carena, Marcela; Lykken, Joseph; /Fermilab; Park, Minjoon; /UC, Davis; Santiago, Jose; /Fermilab

2006-11-01

213

Intra-Laboratory Memo G. B. Stephenson PSC Associate Laboratory Director  

E-print Network

) Argonne, Worker Safety and Health/ Integrated Safety Management System ANL Accelerator Safety Review of Operations the Laboratory Management Manual (APS_1180311) System LMS-PROC-100, Preparing APS 3.1.101 APS User Laboratory Management System Administrative Policies and Policies and Procedures for Procedures (APS_1258423

Kemner, Ken

214

Improvement of Space Shuttle Main Engine Low Frequency Acceleration Measurements  

NASA Technical Reports Server (NTRS)

The noise floor of low frequency acceleration data acquired on the Space Shuttle Main Engines is higher than desirable. Difficulties of acquiring high quality acceleration data on this engine are discussed. The approach presented in this paper for reducing the acceleration noise floor focuses on a search for an accelerometer more capable of measuring low frequency accelerations. An overview is given of the current measurement system used to acquire engine vibratory data. The severity of vibration, temperature, and moisture environments are considered. Vibratory measurements from both laboratory and rocket engine tests are presented.

Stec, Robert C.

1999-01-01

215

Acceleration Measurements Using Smartphone Sensors: Dealing with the Equivalence Principle  

E-print Network

Acceleration sensors built into smartphones, i-pads or tablets can conveniently be used in the Physics laboratory. By virtue of the equivalence principle, a sensor fixed in a non-inertial reference frame cannot discern between a gravitational field and an accelerated system. Accordingly, acceleration values read by these sensors must be corrected for the gravitational component. A physical pendulum was studied by way of example, and absolute acceleration and rotation angle values were derived from the measurements made by the accelerometer and gyroscope. Results were corroborated by comparison with those obtained by video analysis. The limitations of different smartphone sensors are discussed.

Monteiro, Martín; Martí, Arturo C

2014-01-01

216

EPICS BASED HIGH POWER RF CONDITIONING CONTROL SYSTEM FOR THE SNS ACCELERATOR RF TEST FACILITY  

Microsoft Academic Search

Charged particle accelerators use various vacuum windows on their accelerating RF cavities to pass very high RF power through. Before placing on the cavities the windows should be cleaned, baked and fully RF conditioned due to poor vacuum caused by outgassing and other contamination. The linear accelerator (linac) in the Spallation Neutron Source (SNS) in Oak Ridge National Laboratory (ORNL)

S. M. Shajedul Hasan; Johnny Tang; Kay Kasemir; Yoon W. Kang; Mark Crofford

217

Technology development for high power induction accelerators  

SciTech Connect

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

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

1985-06-11

218

The Naples University 3 MV tandem accelerator  

SciTech Connect

The 3 MV tandem accelerator of the Naples University is used for research activities and applications in many fields. At the beginning of operation (1977) the main utilization was in the field of nuclear physics. Later, the realization of new beam lines allowed the development of applied activities as radiocarbon dating, ion beam analysis, biophysics, ion implantation etc. At present, the availability of different ion sources and many improvements on the accelerator allow to run experiments in a wide range of subjects. An overview of the characteristics and major activities of the laboratory is presented.

Campajola, L.; Brondi, A. [Dipartimento di Scienze Fisiche, Universita di Napoli ''Federico II'' Complesso Universitario di Monte S.Angelo via Cintia 80126 Napoli, Italy and Istituto Nazionale di Fisica Nucleare, Sez. di Napoli (Italy)

2013-07-18

219

Teaching and Research with Accelerators at Tarleton State University  

SciTech Connect

Tarleton State University students began performing both research and laboratory experiments using accelerators in 1998 through visitation programs at the University of North Texas, US Army Research Laboratory, and the Naval Surface Warfare Center at Carderock. In 2003, Tarleton outfitted its new science building with a 1 MV pelletron that was donated by the California Institution of Technology. The accelerator has been upgraded and supports a wide range of classes for both the Physics program and the ABET accredited Engineering Physics program as well as supplying undergraduate research opportunities on campus. A discussion of various laboratory activities and research projects performed by Tarleton students will be presented.

Marble, Daniel K. [Department of Engineering and Physisc, Box T-390, Tarleton State University, Stephenville, Texas, 76402 (United States)

2009-03-10

220

Accelerated cleanup risk reduction  

SciTech Connect

There is no proven technology for remediating contaminant plume source regions in a heterogeneous subsurface. This project is an interdisciplinary effort to develop the requisite new technologies so that will be rapidly accepted by the remediation community. Our technology focus is hydrous pyrolysis/oxidation (HPO) which is a novel in situ thermal technique. We have expanded this core technology to leverage the action of steam injection and place an in situ microbial filter downstream to intercept and destroy the accelerated movement of contaminated groundwater. Most contaminant plume source regions, including the chlorinated solvent plume at LLNL, are in subsurface media characterized by a wide range in hydraulic conductivity. At LLNL, the main conduits for contaminant transport are buried stream channels composed of gravels and sands; these have a hydraulic conductivity in the range of 10{sup -1} to 10{sup -2} cm/s. Clay and silt units with a hydraulic conductivity of 10{sup -1} to 10{sup -6} cm/s bound these buried channels; these are barriers to groundwater movement and contain the highest contaminant concentrations in the source region. New remediation technologies are required because the current ones preferentially access the high conductivity units. HPO is an innovative process for the in situ destruction of contaminants in the entire subsurface. It operates by the injection of steam. We have demonstrated in laboratory experiments that many contaminants rapidly oxidize to harmless compounds at temperatures easily achieved by injecting steam, provided sufficient dissolved oxygen is present. One important challenge in a heterogeneous source region is getting heat, contaminants, and an oxidizing agent in the same place at the same time. We have used the NUFT computer program to simulate the cyclic injection of steam into a contaminated aquifer for design of a field demonstration. We used an 8 hour, steam/oxygen injection cycle followed by a 56 hour relaxation period in which the well was `capped`. Our results show the formation of an inclined gas phase during injection and a fast collapse of the steam zone within an hour of terminating steam injection. The majority of destruction occurs during the collapse phase, when contaminant laden water is drawn back towards the well. Little to no noncondensible gasses are created in this process, removing any possibility of sparging processes interfering with contaminant destruction. Our models suggest that the thermal region should be as hot and as large as possible. To have HPO accepted, we need to demonstrate the in situ destruction of contaminants. This requires the ability to inexpensively sample at depth and under high temperatures. We proved the ability to implies monitoring points at depths exceeding 150 feet in highly heterogeneous soils by use of cone penetrometry. In addition, an extractive system has been developed for sampling fluids and measuring their chemistry under the range of extreme conditions expected. We conducted a collaborative field test of HPO at a Superfund site in southern California where the contaminant is mainly creosote and pentachlorophenol. Field results confirm the destruction of contaminants by HPO, validate our field design from simulations, demonstrate that accurate field measurements of the critical fluid parameters can be obtained using existing monitoring wells (and minimal capital cost) and yield reliable cost estimates for future commercial application. We also tested the in situ microbial filter technology as a means to intercept and destroy the accelerated flow of contaminants caused by the injection of steam. A series of laboratory and field tests revealed that the selected bacterial species effectively degrades trichloroethene in LLNL Groundwater and under LLNL site conditions. In addition, it was demonstrated that the bacteria effectively attach to the LLNL subsurface media. An in-well treatability study indicated that the bacteria initially degrade greater than 99% of the contaminant, to concentrations less than regulatory limit

Knapp, R.B.; Aines, R.M.; Blake, R.G.; Copeland, A.B.; Newmark, R.L.; Tompson, A.F.B.

1998-02-01

221

THE DIELECTRIC WALL ACCELERATOR  

SciTech Connect

The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

Caporaso, G J; Chen, Y; Sampayan, S E

2009-08-17

222

Understanding particle acceleration at supernova shocks  

NASA Astrophysics Data System (ADS)

One century after the pioneering discovery of cosmic rays by V. Hess, the present generation of X- and gamma-ray telescopes is finally unravelling the origin of such an extraterrestrial radiation, at least for what concerns particles with energies below ˜10^8 GeV, which are thought to be accelerated at the forward shocks of Galactic supernova remnants (SNRs). I discuss the present theoretical understanding of efficient particle acceleration at non-relativistic, collisionless shocks, addressing with both analytical and numerical (particle-in-cell) techniques the crucial interplay between accelerated ions and magnetic turbulence. In SNRs, in fact, magnetic fields turn out to be a factor of 10-100 larger than in the interstellar medium, because of plasma instabilities triggered by energetic particles. In particular, I show 2D and 3D hybrid (fluid electrons - kinetic ions) simulations of non-relativistic collisionless shocks, pointing out the efficiency of Fermi acceleration and the role of the cosmic-ray-induced filamentation instability in amplifying the magnetic field up to the levels inferred at the blast waves of young Galactic remnants. Finally, I outline the observational counterparts of such a theory of particle acceleration at strong shocks in terms of SNR multi-wavelength emission, with a special attention to Tycho's SNR, arguably the best laboratory where to test hadron acceleration.

Caprioli, Damiano

2013-04-01

223

Linear induction accelerator  

SciTech Connect

A linear induction accelerator of charged particles, containing inductors and an acceleration circuit, characterized by the fact that, for the purpose of increasing the power of the accelerator, each inductor is made in the form of a toroidal line with distributed parameters, from one end of which in the gap of the line a ring commutator is included, and from the other end of the ine a resistor is hooked up, is described.

Bosamykin, V.S.; Pavlovskiy, A.I.

1984-03-01

224

Optically pulsed electron accelerator  

DOEpatents

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

1987-01-01

225

Accelerators and Nobel Laureates  

NSDL National Science Digital Library

This online article written by Sven Kullander at the Nobel e-Museum discusses the importance of particle accelerators to physics in a historical context. After studying their basic operatation, users can then learn about the many accelerator inventions and their assistance in various discoveries such as x-rays and electrons. The website provides links to descriptions of the many Nobel Prize winners who have utilized accelerators in their important work. Users can view images of the large accelerators from all over the world including the United Kingdom, Sweden, and the United State.

Kullander, Sven

226

Charged particle accelerator grating  

DOEpatents

A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

Palmer, Robert B. (Shoreham, NY)

1986-01-01

227

Accelerator-based BNCT.  

PubMed

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. PMID:24365468

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

228

Android Acceleration Application  

NSDL National Science Digital Library

In the first of two sequential lessons, students create mobile apps that collect data from an Android device's accelerometer and then store that data to a database. This lesson provides practice with MIT's App Inventor software and culminates with students writing their own apps for measuring acceleration. In the second lesson, students are given an app for an Android device, which measures acceleration. They investigate acceleration by collecting acceleration vs. time data using the accelerometer of a sliding Android device. Then they use the data to create velocity vs. time graphs and approximate the maximum velocity of the device.

2014-09-18

229

Acceleration of polarized protons in circular accelerators  

SciTech Connect

The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

Courant, E.D.; Ruth, R.D.

1980-09-12

230

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

SciTech Connect

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

Siemann, R.H.; /SLAC

2011-10-24

231

Acceleration Worksheet 8/24/2011 ACCELERATION WORKSHEET  

E-print Network

Acceleration Worksheet 8/24/2011 ACCELERATION WORKSHEET College of Arts and Sciences Name _____________ TO _____________ month/year month/year II. I meet the requirements for acceleration under [fill out either a) or b;Acceleration Worksheet 8/24/2011 Acceleration 2011-2012 Courses of Study The faculty of the college desires

Davis, H. Floyd

232

Centrifuge Study of Pilot Tolerance to Acceleration and the Effects of Acceleration on Pilot Performance  

NASA Technical Reports Server (NTRS)

A research program the general objective of which was to measure the effects of various sustained accelerations on the control performance of pilots, was carried out on the Aviation Medical Acceleration Laboratory centrifuge, U.S. Naval Air Development Center, Johnsville, PA. The experimental setup consisted of a flight simulator with the centrifuge in the control loop. The pilot performed his control tasks while being subjected to acceleration fields such as might be encountered by a forward-facing pilot flying an atmosphere entry vehicle. The study was divided into three phases. In one phase of the program, the pilots were subjected to a variety of sustained linear acceleration forces while controlling vehicles with several different sets of longitudinal dynamics. Here, a randomly moving target was displayed to the pilot on a cathode-ray tube. For each combination of acceleration field and vehicle dynamics, pilot tracking accuracy was measured and pilot opinion of the stability and control characteristics was recorded. Thus, information was obtained on the combined effects of complexity of control task and magnitude and direction of acceleration forces on pilot performance. These tests showed that the pilot's tracking performance deteriorated markedly at accelerations greater than about 4g when controlling a lightly damped vehicle. The tentative conclusion was also reached that regardless of the airframe dynamics involved, the pilot feels that in order to have the same level of control over the vehicle, an increase in the vehicle dynamic stability was required with increases in the magnitudes of the acceleration impressed upon the pilot. In another phase, boundaries of human tolerance of acceleration were established for acceleration fields such as might be encountered by a pilot flying an orbital vehicle. A special pilot restraint system was developed to increase human tolerance to longitudinal decelerations. The results of the tests showed that human tolerance of longitudinal deceleration forces was considerably improved through use of the special restraint system.

Creer, Brent Y.; Smedal, Harald A.; Wingrove, Rodney C.

1960-01-01

233

NSLS source development laboratory  

SciTech Connect

The National Synchrotron Light Source (NSLS) has initiated an ambitious project to develop fourth generation radiation sources. To achieve this goal, the Source Development Laboratory (SDL) builds on the experience gained at the NSLS, and at the highly successful BNL Accelerator Test Facility. The SDL accelerator system will consist of a high brightness short pulse linac, a station for coherent synchrotron and transition radiation experiments, a short bunch storage ring, and an ultra-violet free electron laser utilizing the NISUS wiggler. The electrons will be provided by a laser photocathode gun feeding a 210 MeV S-band electron linac, with magnetic bunch compression at 80 MeV. Electron bunches as short as 100 {mu}m with 1 nC charge will be used for pump-probe experiments utilizing coherent transition radiation. Beam will also be injected into a compact storage ring which will be a source of millimeter wave coherent synchrotron radiation. The linac will also serve as the driver for an FEL designed to allow the study of various aspects of single pass amplifiers. The first FEL configuration will be as a self-amplified spontaneous emission (SASE) FEL at 900 nm. Seeded beam and sub-harmonic seeded beam operations will push the output wavelength below 200 nm. Chirped pulse amplification (CPA) operation will also be possible, and a planned energy upgrade (by powering a fifth linac section) to 310 MeV will extend the wavelength range of the FEL to below 100 nm.

Ben-Zvi, I.; Blum, E.; Johnson, E.D. [and others

1995-09-01

234

Lunar laboratory  

SciTech Connect

An international research laboratory can be established on the Moon in the early years of the 21st Century. It can be built using the transportation system now envisioned by NASA, which includes a space station for Earth orbital logistics and orbital transfer vehicles for Earth-Moon transportation. A scientific laboratory on the Moon would permit extended surface and subsurface geological exploration; long-duration experiments defining the lunar environment and its modification by surface activity; new classes of observations in astronomy; space plasma and fundamental physics experiments; and lunar resource development. The discovery of a lunar source for propellants may reduce the cost of constructing large permanent facilities in space and enhance other space programs such as Mars exploration. 29 refs.

Keaton, P.W.; Duke, M.B.

1986-01-01

235

Laboratory accreditation  

SciTech Connect

Accreditation can offer many benefits to a testing or calibration laboratory, including increased marketability of services, reduced number of outside assessments, and improved quality of services. Compared to ISO 9000 registration, the accreditation process includes a review of the entire quality system, but in addition a review of testing or calibration procedures by a technical expert and participation in proficiency testing in the areas of accreditation. Within the DOE, several facilities have recently become accredited in the area of calibration, including Sandia National Laboratories, Oak Ridge, AlliedSignal FM and T; Lockheed Martin Idaho Technologies Co., and Pacific Northwest National Lab. At the national level, a new non-profit organization was recently formed called the National Cooperation for Laboratory Accreditation (NACLA). The goal of NACLA is to develop procedures, following national and international requirements, for the recognition of competent accreditation bodies in the US. NACLA is a voluntary partnership between the public and private sectors with the goal of a test or calibration performed once and accepted world wide. The NACLA accreditation body recognition process is based on the requirements of ISO Guide 25 and Guide 58. A membership drive will begin some time this fall to solicit organizational members and an election of a permanent NACLA Board of Directors will follow later this year or early 1999.

Pettit, R.B.

1998-08-01

236

Accelerators (3/5)  

ScienceCinema

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 Prerequisite knowledge: Previous knowledge of accelerators is not required.

None

2011-10-06

237

J-PARC Accelerator  

SciTech Connect

The Japan Proton Accelerator Research Complex (J-PARC) is under construction in Tokai site. The linac beam commissioning started last fall, while the beam commissioning of the 3-GeV Rapid-Cycling Synchrotron (RCS) will start this fall. The status of the J-PARC accelerator is reported with emphasis on the technical development accomplished for the J-PARC.

Yamazaki, Yoshishige [J-PARC Center High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Organization (JAEA) Shirakata-Shirane, Tokai-Mura, Naka-Gun, Ibaraki-Ken (Japan)

2008-02-21

238

Accelerators Beyond The Tevatron?  

SciTech Connect

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?.

Lach, Joseph [Fermi National Accelerator Laboratory, P.O Box 500, Batavia Illinois (United States)

2010-07-29

239

Acceleration of Gravity 2  

NSDL National Science Digital Library

This lab is between a Level 2 and Level 3 inquiry activity in that it should be assigned after students understand acceleration but before they learn about the acceleration gravity. Because there are many sources of error when using a pendulum, students c

Michael Horton

2009-05-30

240

Particle Acceleration in Jets  

NASA Technical Reports Server (NTRS)

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

Nishikawa, Ken-Ichi

2005-01-01

241

Microscale acceleration history discriminators  

DOEpatents

A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

Polosky, Marc A. (Albuquerque, NM); Plummer, David W. (Albuquerque, NM)

2002-01-01

242

FERMI ACCELERATION. DMITRY DOLGOPYAT  

E-print Network

by Enrico Fermi in 1949, to explain heating of particles in cosmic rays. Fermi studied charged particles of the first papers on this subject was work of Enrico Fermi on the origin of cosmic radiation [22]. FermiFERMI ACCELERATION. DMITRY DOLGOPYAT Abstract. Fermi acceleration is a mechanism, first suggested

Dolgopyat, Dmitry

243

Flow accelerated corrosion  

SciTech Connect

Flow accelerated corrosion has recently attracted attention in association with heat recovery steam generators. Apparently, the phenomenon is more widespread than is realized and has been misdiagnosed as simple erosion. This paper addresses the principal environmental conditions that have been linked to flow accelerated corrosion and it illustrates the phenomenon with case histories.

Port, R.D. [Nalco Chemical Co., Naperville, IL (United States)

1998-12-31

244

Accelerators (5/5)  

ScienceCinema

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 Prerequisite knowledge: Previous knowledge of accelerators is not required.

None

2011-10-06

245

Accelerators Beyond The Tevatron?  

SciTech Connect

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?

Lach, Joseph; /Fermilab

2010-07-01

246

ACCELERATOR RESEARCH STUDIES  

SciTech Connect

ACCELERATOR RESEARCH STUDIES Task A: Study of the Physics of Space-Charge Dominated Beams for Advanced Accelerator Applications Task B: Studies of High-Power Gyroklystrons and Application to Linear Colliders Task C: Theory and Simulation of the Physics Space-Charge Dominated Beams Annual Report for the Period June 1, 2003 to May 31, 2004

P.G. O'Shea, M. Reiser, V. L. Granatstein, W. Lawson, I. Haber, R. Kishek

2004-01-23

247

Scaling FFAG accelerator for muon acceleration  

SciTech Connect

Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. Such principles and matching issues are detailed in this paper. An application of these new concepts is presented to overcome problems in the PRISM project.

Lagrange, JB.; Planche, T. [Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku Kyoto, 615-8530 (Japan); Mori, Y. [Kyoto University Research Reactor Institute, Department of Nuclear Science and Engineering, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka, 590-0494 (Japan)

2011-10-06

248

Laboratory for IT Entrepreneurship Transforming IT ideas into ventures  

E-print Network

Laboratory for IT Entrepreneurship Transforming IT ideas into ventures SEMINAR ANNOUNCEMENT insights that can help aspiring entrepreneurs to accelerate the development of their business ventures and guide IT ventures from idea to launch. #12;

249

Collinear wake field acceleration  

SciTech Connect

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.

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

1985-04-01

250

Symmetry Restoration By Acceleration  

E-print Network

The restoration of spontaneous symmetry breaking for a scalar field theory for an accelerated observer is discussed by the one-loop effective potential calculation and by considering the effective potential for composite operators. Above a critical acceleration, corresponding to the critical restoration temperature,T_c, for a Minkowski observer by Unruh relation, i.e. a_c/2\\pi=T_c, the symmetry is restored. This result confirms other recent calculations in effective field theories that symmetry restoration can occur for an observer with an acceleration larger than some critical value. From the physical point of view, a constant acceleration is locally equivalent to a gravitational field and the critical acceleration to restore the spontaneous symmetry breaking corresponds to a huge gravitational effect which, therefore, prevents boson condensation.

P. Castorina; M. Finocchiaro

2012-07-16

251

New underground laboratories: Europe, Asia and the Americas  

NASA Astrophysics Data System (ADS)

Deep underground laboratories provide the low radioactive background environment necessary to explore the highest energy scales that cannot be reached with accelerators, by searching for extremely rare phenomena. In addition, these laboratories provide unique opportunities to sectors of other fields: geodynamics, rock mechanics, hydrology and the study of life under extreme conditions. Underground laboratories of different size and depth exist in all the regions. This article is focussed on future perspectives, reviewing the newer facilities, those still under project and the space becoming available at the older laboratories. We shall not discuss the existing or proposed facilities dedicated to detectors of long base line experiment with reactor or accelerator beams.

Bettini, Alessandro

2014-09-01

252

Laser acceleration with open waveguides  

Microsoft Academic Search

A unified framework based on solid-state open waveguides is developed to overcome all three major limitations on acceleration distance and hence on the feasibility of two classes of laser acceleration. The three limitations are due to laser diffraction, acceleration phase slippage, and damage of waveguide structure by a high power laser. The two classes of laser acceleration are direct-field acceleration

Ming Xie; Ming

1999-01-01

253

Space Experiments with Particle Accelerators: SEPAC  

NASA Technical Reports Server (NTRS)

The Space Experiments with Particle Accelerators (SEPAC), which flew on the Atmospheric Laboratory for Applications and Science (ATLAS) 1 mission, used new techniques to study natural phenomena in the Earth's upper atmosphere, ionosphere and magnetosphere by introducing energetic perturbations into the system from a high power electron beam with known characteristics. Properties of auroras were studied by directing the electron beam into the upper atmosphere while making measurements of optical emissions. Studies were also performed of the critical ionization velocity phenomenon.

Burch, J. L.; Roberts, W. T.; Taylor, W. W. L.; Kawashima, N.; Marshall, J. A.; Moses, S. L.; Neubert, T.; Mende, S. B.; Choueiri, E. Y.

1994-01-01

254

BNL ACCELERATOR TEST FACILITY CONTROL SYSTEM UPGRADE.  

SciTech Connect

Brookhaven National Laboratory's Accelerator Test Facility (ATF) has embarked on a complete upgrade of its decade old computer system. The planned improvements affect every major component: processors (Intel Pentium replaces VAXes), operating system (Linux/Real-Time Linux supplants OpenVMS), and data acquisition equipment (fast Ethernet equipment replaces CAMAC serial highway.) This paper summarizes the strategies and progress of the upgrade along with plans for future expansion.

MALONE,R.; BEN-ZVI,I.; WANG,X.; YAKIMENKO,V.

2001-06-18

255

Engineering design of the Saturn accelerator  

Microsoft Academic Search

The Saturn accelerator is a large flash x-ray simulator being constructed as a part of Sandia's Simulation Technology Laboratory. The performance goal of the machine is to provide x-ray exposure capabilities of 5 x 10¹² rads\\/s (Si) and 5 cal\\/g (Au) uniformly distributed over a 500 cm² target area. The operational goal of the machine is to provide this exposure

J. D. Boyes; J. S. Cap; G. M. Douglas; T. L. Franklin; J. M. Hart; H. C. Ives; S. J. Robischon; B. L. Smith; W. O. Stoppkotte; D. M. VanDeValde

1987-01-01

256

Measurement of absolute gravity acceleration in Firenze  

NASA Astrophysics Data System (ADS)

This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) ?Gal and (980 492 048.3 ± 3.0) ?Gal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

2011-01-01

257

The Tandem-RFQ Linac Booster at Sandia National Laboratories  

Microsoft Academic Search

A booster linac based on the Radio Frequency Quadrupole (RFQ linac) has been put into routine operation on the 6.5 MV EN tandem accelerator at the Sandia National Laboratories (SNL) Ion Beam Materials Research Lab (IBMRL) for Radiation Effects Microscopy (REM) experiments with high energy, heavy ion beams. The booster linac consists of two RFQ stages that accelerate heavy ions

F. D. McDaniel; B. L. Doyle; D. L. Buller; R. W. Hamm; Kirtland AFB

258

The Tandem-RFQ Linac Booster at Sandia National Laboratories  

Microsoft Academic Search

A booster linac based on the Radio Frequency Quadrupole (RFQ linac) has been put into routine operation on the 6.5 MV EN tandem accelerator at the Sandia National Laboratories (SNL) Ion Beam Materials Research Lab (IBMRL) for Radiation Effects Microscopy (REM) experiments with high energy, heavy ion beams. The booster linac consists of two RFQ stages that accelerate heavy ions

F. D. McDaniel; B. L. Doyle; P. Rossi; D. L. Buller; R. W. Hamm; H. Schone

2003-01-01

259

Accelerator Facilities for Radiation Research  

NASA Technical Reports Server (NTRS)

HSRP Goals in Accelerator Use and Development are: 1.Need for ground-based heavy ion and proton facility to understand space radiation effects discussed most recently by NAS/NRC Report (1996). 2. Strategic Program Goals in facility usage and development: -(1) operation of AGS for approximately 600 beam hours/year; (2) operation of Loma Linda University (LLU) proton facility for approximately 400 beam hours/year; (3) construction of BAF facility; and (4) collaborative research at HIMAC in Japan and with other existing or potential international facilities. 3. MOA with LLU has been established to provide proton beams with energies of 40-250 important for trapped protons and solar proton events. 4. Limited number of beam hours available at Brookhaven National Laboratory's (BNL) Alternating Gradient Synchrotron (AGS).

Cucinotta, Francis A.

1999-01-01

260

THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY The Radiological Research Accelerator Facility  

E-print Network

THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY 1 The Radiological Research Accelerator Facility for Radiological Research (CRR). Using the mi- crobeam facility, 10% of the cells were irradiated through

261

Deuterium accelerator experiments for APT.  

SciTech Connect

Sandia National Laboratories in California initiated an experimental program to determine whether tritium retention in the tube walls and permeation through the tubes into the surrounding coolant water would be a problem for the Accelerator Production of Tritium (APT), and to find ways to mitigate the problem, if it existed. Significant holdup in the tube walls would limit the ability of APT to meet its production goals, and high levels of permeation would require a costly cleanup system for the cooling water. To simulate tritium implantation, a 200 keV accelerator was used to implant deuterium into Al 6061-T and SS3 16L samples at temperatures and particle fluxes appropriate for APT, for times varying between one week and five months. The implanted samples were characterized to determine the deuterium retention and Permeation. During the implantation, the D(d,p)T nuclear reaction was used to monitor the build-up of deuterium in the implant region of the samples. These experiments increased in sophistication, from mono-energetic deuteron implants to multi-energetic deuteron and proton implants, to more accurately reproduce the conditions expected in APT. Micron-thick copper, nickel, and anodized aluminum coatings were applied to the front surface of the samples (inside of the APT walls) in an attempt to lower retention and permeation. The reduction in both retention and permeation produced by the nickel coatings, and the ability to apply them to the inside of the APT tubes, indicate that both nickel-coated Al 6061-T6 and nickel-coated SS3 16L tubes would be effective for use in APT. The results of this work were submitted to the Accelerator Production of Tritium project in document number TPO-E29-Z-TNS-X-00050, APT-MP-01-17.

Causey, Rion A. (Sandia National Laboratories, Livermore, CA); Hertz, Kristin L. (Sandia National Laboratories, Livermore, CA); Cowgill, Donald F. (Sandia National Laboratories, Livermore, CA)

2005-08-01

262

Tethered gravity laboratories study  

NASA Technical Reports Server (NTRS)

The scope of the study is to investigate ways of controlling the microgravity environment of the International Space Station by means of a tethered system. Four main study tasks were performed. First, researchers analyzed the utilization of the tether systems to improve the lowest possible steady gravity level on the Space Station and the tether capability to actively control the center of gravity position in order to compensate for activities that would upset the mass distribution of the Station. The purpose of the second task was to evaluate the whole of the experiments performable in a variable gravity environment and the related beneficial residual accelerations, both for pure and applied research in the fields of fluid, materials, and life science, so as to assess the relevance of a variable g-level laboratory. The third task involves the Tethered Variable Gravity Laboratory. The use of the facility that would crawl along a deployed tether and expose experiments to varying intensities of reduced gravity is discussed. Last, a study performed on the Attitude Tether Stabilizer concept is discussed. The stabilization effect of ballast masses tethered to the Space Station was investigated as a means of assisting the attitude control system of the Station.

Lucchetti, F.

1990-01-01

263

Archimedes Laboratory  

NSDL National Science Digital Library

Proving that geometry can be more fun than a barrel of monkeys, Archimedes Laboratory is "an 'intuitive' puzzle site with fewer formulas and more visuals, which may encourage students learning this science or just constitute a platform for reflection." Probably the most strictly educational section of the site is Math to Discover, which contains discussions of the history of numbers and mathematical patterns, to name a few. Also of interest are the Puzzles to Make and Puzzles to Solve sections. Visitors can follow online instructions to create geometrical curiosities or browse a small selection of impossible object images.

264

Materials for Accelerator Technologies Beyond the Niobium Family  

SciTech Connect

Three niobium-based materials make up the entire present portfolio of superconducting technology for accelerators: Nb-Ti and Nb{sub 3}Sn magnet wires and pure niobium for RF cavities. Because these materials are at a high level of maturity, limits imposed by the boundaries of their superconductivity constrain the energy reach of accelerators to several TeV. We sketch here a plan for targeted development of emerging higher field and higher temperature superconductors that could enable accelerators at significantly higher energies. Niobium-based superconductors are the crucial enablers of present accelerators. The Nb-Ti LHC dipole and quadrupole wires, with transition temperature T{sub c} of 9 K and upper critical field H{sub c2} of 15 T, represent the highest form of superconductor strand art: massive, quarter-ton conductor billets are drawn from 300 mm diameter to {approx}1 mm as a single, multi-kilometer-long piece, while retaining uniformity of the several thousand Nb-Ti filaments to within 5% at the scale of a few micrometers. Strands are twisted into fully transposed cables with virtually no loss, preserving a carefully tuned nanostructure that generates the high flux-pinning forces and high current densities to enable high magnetic fields. Nb{sub 3}Sn, with twice the T{sub c} and H{sub c2}, is now approaching this level of conductor art, where over the last 5 years the LHC Accelerator Research Program (LARP) and the Next European Dipole (NED) program have demonstrated that Nb{sub 3}Sn can be made into 4 meter long quadrupoles with 12 T fields and 250 T/m gradients. Linear accelerators at TJNAF, ORNL (SNS), and under construction for the European XFEL exploit niobium superconducting radio-frequency (SRF) technology, with gradients at {approx}20 MV/m. Tremendous research and development is underway to realize high-power goals for Project X at FNAL and for a possible ILC at 35 MV/m gradients. Despite these impressive achievements, the very maturity of these niobium-based technologies makes them incapable of additional leaps from the several-TeV scale. Nb-Ti is already nearly perfect and operates at the limit of the superconducting phase. Further perfection of Nb cavities and Nb{sub 3}Sn magnets might provide 50 % growth in energy, based on proof-of-principle demonstrations that approach theoretical limits, e.g. 52 MV/m gradient in re-entrant Nb cavities and 18 T dipoles made from Nb3Sn strand. However, operation close to superconducting margins is risky, and cost tradeoffs to execute such a high degrees of perfection are likely to be negative.

Cooley, Lance; Larbalestier, David; Ghosh, Arup; Tollestrup, Alvin; /Fermilab

2009-01-01

265

Computational studies and optimization of wakefield accelerators  

SciTech Connect

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

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

2008-06-16

266

Amps particle accelerator definition study  

NASA Technical Reports Server (NTRS)

The Particle Accelerator System of the AMPS (Atmospheric, Magnetospheric, and Plasmas in Space) payload is a series of charged particle accelerators to be flown with the Space Transportation System Shuttle on Spacelab missions. In the configuration presented, the total particle accelerator system consists of an energetic electron beam, an energetic ion accelerator, and both low voltage and high voltage plasma acceleration devices. The Orbiter is illustrated with such a particle accelerator system.

Sellen, J. M., Jr.

1975-01-01

267

The MESA accelerator  

SciTech Connect

The MESA accelerator will operate for particle and nuclear physics experiments in two different modes. A first option is conventional c.w. acceleration yielding 150-200MeV spin-polarized external beam. Second, MESA will be operated as a superconducting multi-turn energy recovery linac (ERL), opening the opportunity to perform experiments with a windowless target with beam current of up to 10 mA. The perspectives for innovative experiments with such a machine are discussed together with a sketch of the accelerator physics issues that have to be solved.

Aulenbacher, Kurt [Institut für Kernphysik, Johannnes-Gutenberg-Universität Mainz (Germany)

2013-11-07

268

Laboratory dynamos  

NASA Astrophysics Data System (ADS)

The magnetism of the planets, including Earth, is generated by dynamo action, i.e. self-generation of a magnetic field due to the fluid motion of liquid iron inside the planetary cores. During the last decades, laboratory experiments became an essential part of the research on dynamo action, complementing both observations and theory. In this talk, I will review some recent results of the Von-Karman Sodium (VKS) experiment. The VKS experiment has been designed to achieve dynamo action in a turbulent flow of liquid metal. In this experiment, 150 liters of liquid sodium are stirred by the counter-rotation of two bladed discs in a cylindrical tank. When the discs are rotating sufficiently fast, a dipolar magnetic field, aligned with the axis of rotation, is generated by dynamo action. In addition,a lot of dynamical regimes can be observed, like chaotic polarity inversions of the field very similar to geomagnetic reversals. In some cases, the experiment can also generate hemispherical dynamos similar to some planetary fields. These different behaviors will be described within the framework of simple theoretical models. I will discuss how these results, and the corresponding theoretical descriptions, can provide a better understanding of some aspects of the geomagnetic field dynamics. Finally, I will present current perspectives for the next generation of laboratory dynamo experiments.

Gissinger, Christophe

2014-05-01

269

Information Technology Laboratory LETTER FROM THE DIRECTOR  

E-print Network

Information Technology Laboratory #12;LETTER FROM THE DIRECTOR W elcome to the Informa- tion and Tech- nology, ITL accelerates the development and deployment of information and communica- tion systems infra- structure for emerging information technologies and applications. We accomplish these goals

Magee, Joseph W.

270

LAWRENCE BERKELEY NATIONAL LABORATORY About Berkeley Lab  

E-print Network

and energy research. Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist whoLAWRENCE BERKELEY NATIONAL LABORATORY About Berkeley Lab Berkeley Lab is a U.S. Department accelerator that opened the door to high-energy physics. It was Lawrence's belief that scientific research

Eisen, Michael

271

Proton Injector for CW-Mode Linear Accelerators  

Microsoft Academic Search

Numerous applications exist for CW linear accelerators with final energies in the 0.5 to 4.0 MeV proton energy range. Typical proton current at the linac output energy is 20 mA. An important subsystem for the accelerator facility is a reliable dc mode proton injector. We present here design and laboratory results for a dc, 25-keV, 30-mA proton injector. The proton

Joseph D. Sherman; Donald Swenson; Frank Guy; Cody Love; Joel Starling; Carl Willis

2009-01-01

272

Cell design for the DARHT linear induction accelerators  

Microsoft Academic Search

The dual-axis radiographic hydrotest facility at Los Alamos National Laboratory will employ two linear induction accelerators to produce intense, bremsstrahlung X-ray pulses for flash radiography. The accelerator cell design for a 3-kA, 16-20-MeV, 60-ns flattop, high-brightness electron beam is presented. The cell is optimized for high-voltage stand-off while also minimizing the transverse impedance. Measurements of high-voltage RF characteristics are summarized

M. Burns; P. Allison; L. Earley; D. Liska; C. Mockler; J. Ruhe; H. Tucker; L. Walling

1991-01-01

273

Microgravity Acceleration Measurement System for the International Space Station  

Microsoft Academic Search

The Microgravity Acceleration Measurement System (MAMS) is a high resolution and wide dynamic range dual sensor-based accelerometry instrumentation system to be installed within the International Space Station's (ISS) US Laboratory Module. The MAMS instrument will provide highly accurate acceleration measurement data over the nano-g to milli-g range characterizing the Lab Module environment in the frequency spectrum from 10-4 Hz to

James E. Rice; James C. Fox; William G. Lange; Robert W. Dietrich; W. O. Wagar

1999-01-01

274

Non-accelerator experiments  

SciTech Connect

This report discusses several topics which can be investigated without the use of accelerators. Topics covered are: (1) proton decay, (2) atmospheric neutrinos, (3) neutrino detection, (4) muons from Cygnus X-3, and (5) the double-beta decay.

Goldhaber, M.

1986-01-01

275

Accelerator on a Chip  

SciTech Connect

SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

England, Joel

2014-06-30

276

Accelerated test program  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

277

Charged particle accelerator grating  

DOEpatents

A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

Palmer, R.B.

1985-09-09

278

Laser electron accelerator  

Microsoft Academic Search

An intense electromagnetic pulse can create weak plasma oscillations through the action of the nonlinear ponderomotive force. Electrons trapped in the wake can be accelerated to high energy. Existing glass lasers of power density 10 to the 18th W\\/sq cm shone on plasmas of densities 10 to the 18th\\/cu cm can yield gigaelectronvolts of electron energy per centimeter of acceleration

T. Tajima; J. M. Dawson

1979-01-01

279

Motion with Constant Acceleration  

NSDL National Science Digital Library

The purpose of this experiment is to track the motion for an air cart on a sloped track to fall a distance x with constant acceleration a = g sinq. You will verify that the distance and velocity along the incline are given by the parabola x = xo + vo t +1/2at2 and the line v = vo +at. Finally, you will determine the acceleration due to gravity.

Dr. Russell Herman

280

Rolamite acceleration sensor  

DOEpatents

A rolamite acceleration sensor is described which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently. 6 figures.

Abbin, J.P.; Briner, C.F.; Martin, S.B.

1993-12-21

281

Rolamite acceleration sensor  

DOEpatents

A rolamite acceleration sensor which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently.

Abbin, Joseph P. (Albuquerque, NM); Briner, Clifton F. (Albuquerque, NM); Martin, Samuel B. (Albuquerque, NM)

1993-01-01

282

Impulsive acceleration of strongly magnetized relativistic flows  

NASA Astrophysics Data System (ADS)

The strong variability of magnetic central engines of active galactic nuclei (AGNs) and gamma-ray bursts (GRBs) may result in highly intermittent strongly magnetized relativistic outflows. We find a new magnetic acceleration mechanism for such impulsive flows that can be much more effective than the acceleration of steady-state flows. This impulsive acceleration results in kinetic-energy-dominated flows that are conducive to efficient dissipation at internal magnetohydrodynamic shocks on astrophysically relevant distances from the central source. For a spherical flow, a discrete shell ejected from the source over a time t0 with Lorentz factor ?˜ 1 and initial magnetization ?0=B20/4??0c2? 1 quickly reaches a typical Lorentz factor ?˜?1/30 and magnetization ?˜?2/30 at the distance R0?ct0. At this point, the magnetized shell of width ?˜R0 in the laboratory frame loses causal contact with the source and continues to accelerate by spreading significantly in its own rest frame. The expansion is driven by the magnetic pressure gradient and leads to relativistic relative velocities between the front and back of the shell. While the expansion is roughly symmetric in the centre of the momentum frame, in the laboratory frame, most of the energy and momentum remains in a region (or shell) of width ?˜R0 at the head of the flow. This acceleration proceeds as ?˜ (?0R/R0)1/3 and ?˜?2/30 (R/R0)-1/3 until reaching a coasting radius Rc˜R0?20, where the kinetic energy becomes dominant: ?˜?0 and ?˜ 1 at Rc. The shell then starts coasting and spreading (radially), its width growing as ?˜R0(R/Rc), causing its magnetization to drop as ?˜Rc/R at R > Rc. Given the typical variability time-scales of AGNs and GRBs, the magnetic acceleration in these sources is a combination of the quasi-steady-state collimation acceleration close to the source and the impulsive (conical or locally quasi-spherical) acceleration farther out. The interaction with the external medium, which can significantly affect the dynamics, is briefly addressed in the discussion.

Granot, Jonathan; Komissarov, Serguei S.; Spitkovsky, Anatoly

2011-02-01

283

THE ACCELERATOR TUBE DEVELOPMENT PROGRAMME AT DARESBURY LABORATORY  

E-print Network

of 20 to 30 MV. 2. Construction. - Early work on the development of a diffusion bonding process suitable to thermal expansion imba- lance and a more reliable method of welding to the end electrode was developed

Boyer, Edmond

284

Stanford Linear Accelerator Center Stanford Synchrotron Radiation Laboratory  

E-print Network

, and recognition through international awards. Recent user research highlights include: · Understanding of which was conducted at SSRL's macromolecular crystallography beam lines. · Learning how nature splits Facilities Currently there are 11 beam ports on SPEAR3: 7 insertion-devices and 4 bending-magnet beam lines

Kay, Mark A.

285

Acceleration Disturbances onboard of Geodetic Precision Space Laboratories  

NASA Astrophysics Data System (ADS)

Bartlomiej Oszczak, b@dgps.pl University of Warmia and Mazury in Olsztyn, Poland, Olsztyn, Poland Olga Maciejczyk, omaciejczyk@gmail.com Poland In this paper there is presented the study on the parameters of the ASG-EUPOS real-time RTK service NAWGEO such as: accuracy, availability, integrity and continuity. Author's model is used for tests. These parameters enable determination of the quality of received information and practical applications of the service. Paper includes also the subject related to the NAWGEO service and algorithms used in determination of mentioned parameters. The results of accuracy and precision analyses and study on availability demonstrated that NAWGEO service enables a user a position determination with a few centimeters accuracy with high probability in any moment of time.

Peterseim, Nadja; Jakob, Flury; Schlicht, Anja

286

Stirling laboratory research engine survey report  

NASA Technical Reports Server (NTRS)

As one step in expanding the knowledge relative to and accelerating the development of Stirling engines, NASA, through the Jet Propulsion Laboratory (JPL), is sponsoring a program which will lead to a versatile Stirling Laboratory Research Engine (SLRE). An objective of this program is to lay the groundwork for a commercial version of this engine. It is important to consider, at an early stage in the engine's development, the needs of the potential users so that the SLRE can support the requirements of educators and researchers in academic, industrial, and government laboratories. For this reason, a survey was performed, the results of which are described.

Anderson, J. W.; Hoehn, F. W.

1979-01-01

287

Linear resonance ion accelerators with a focusing axisymmetric accelerating field  

SciTech Connect

The two-wave approximation is used to analyze the design of linear resonance ion accelerators with a focusing axisymmetric accelerating field in several cases of practical interest. Special features and characteristics are described, such as the length of the region of phase focusing, acceleration rate, maximum current, and type of accelerated ions.

Baev, V.K.; Gavrilov, N.M.; Minaev, S.A.; Shal'nov, A.V.

1983-07-01

288

Effect of gasoline octane quality on vehicle acceleration performance  

SciTech Connect

A study was conducted under the auspices of the Coordinating Research Council, Inc. (CRC) to assess the potential effects of gasoline octane quality on vehicle acceleration performance. Twelve participating laboratories, representing both the oil and the automotive industries, tested a total of 182 vehicles as part of the 1989 CRC Octane Number Requirement Survey. The vehicles consisted of 78 with electronic knock control systems and 104 without. All testing was performed using the 1989/1990 CRC FBRU fuel series. The results showed that acceleration performance of vehicles with knock sensors was significantly affected by gasoline octane quality. Octane effects on acceleration performance were most pronounced at maximum-throttle (detent) conditions and at octane levels below the vehicles' octane requirements; however, some knock-sensor vehicles did show improved acceleration performance with fuels at octane levels above the octane number requirement. Acceleration performance in non-knock sensor vehicles was unaffected by octane quality.

Not Available

1991-07-01

289

Ion accelerator applications in medicine and cultural heritage  

NASA Astrophysics Data System (ADS)

Formerly, accelerator laboratories were mainly dedicated to nuclear physics. Today, they are used in up-coming research fields and applications like material analysis and material science as well as biology, medicine or archaeology. Practical applications have been developed, involving hospitals, industry and even humanists in the use of accelerators. This paper focuses on some medical and analytical applications of the HMI accelerator facility, especially for eye tumour therapy and archaeology. The innovation of techniques to measure the dose distribution, the development of an automated monitoring procedure allowing an improved and accelerated patient positioning, and the implementation of a modern treatment planning system will be presented first. In the second part, the employment of accelerators in better understanding of our cultural heritage will be shown.

Denker, A.; Cordini, D.; Heufelder, J.; Homeyer, H.; Kluge, H.; Simiantonakis, I.; Stark, R.; Weber, A.

2007-09-01

290

HF Accelerated Electron Fluxes, Spectra, and Ionization  

NASA Astrophysics Data System (ADS)

Wave particle interactions, an essential aspect of laboratory, terrestrial, and astrophysical plasmas, have been studied for decades by transmitting high power HF radio waves into Earth's weakly ionized space plasma, to use it as a laboratory without walls. Application to HF electron acceleration remains an active area of research (Gurevich in Usp Fizicheskikh Nauk 177(11):1145-1177, 2007) today. HF electron acceleration studies began when plasma line observations proved (Carlson et al. in J Atmos Terr Phys 44:1089-1100, 1982) that high power HF radio wave-excited processes accelerated electrons not to ~eV, but instead to -100 times thermal energy (10 s of eV), as a consequence of inelastic collision effects on electron transport. Gurevich et al (J Atmos Terr Phys 47:1057-1070, 1985) quantified the theory of this transport effect. Merging experiment with theory in plasma physics and aeronomy, enabled prediction (Carlson in Adv Space Res 13:1015-1024, 1993) of creating artificial ionospheres once ~GW HF effective radiated power could be achieved. Eventual confirmation of this prediction (Pedersen et al. in Geophys Res Lett 36:L18107, 2009; Pedersen et al. in Geophys Res Lett 37:L02106, 2010; Blagoveshchenskaya et al. in Ann Geophys 27:131-145, 2009) sparked renewed interest in optical inversion to estimate electron spectra in terrestrial (Hysell et al. in J Geophys Res Space Phys 119:2038-2045, 2014) and planetary (Simon et al. in Ann Geophys 29:187-195, 2011) atmospheres. Here we present our unpublished optical data, which combined with our modeling, lead to conclusions that should meaningfully improve future estimates of the spectrum of HF accelerated electron fluxes. Photometric imaging data can significantly improve detection of emissions near ionization threshold, and confirm depth of penetration of accelerated electrons many km below the excitation altitude. Comparing observed to modeled emission altitude shows future experiments need electron density profiles to derive more accurate HF electron flux spectra.

Carlson, Herbert C.; Jensen, Joseph B.

2014-12-01

291

High transformer ratio drive beams for wakefield accelerator studies  

SciTech Connect

For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Max Planck Institute for Physics, 80805 Munich (Germany); University of California Los Angeles, Los Angeles, CA 90095 (United States); Tsinghua University, Beijing (China)

2012-12-21

292

High transformer ratio drive beams for wakefield accelerator studies  

NASA Astrophysics Data System (ADS)

For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W.

2012-12-01

293

Accelerator technology program. Progress report, January-June 1981  

SciTech Connect

This report covers the activities of Los Alamos National Laboratory's Accelerator Technology Division during the first 6 months of calendar 1981. We discuss the Division's major projects, which reflect a variety of applications and sponsors. The varied technologies concerned with the Proton Storage ring are concerned with the Proton Storage Ring are continuing and are discussed in detail. For the racetrack microtron (RTM) project, the major effort has been the design and construction of the demonstration RTM. Our development of the radio-frequency quadrupole (RFQ) linear accelerator continues to stimulate interest for many possible applications. Frequent contacts from other laboratories have revealed a wide acceptance of the RFQ principle in solving low-velocity acceleration problems. In recent work on heavy ion fusion we have developed ideas for funneling beams from RFQ linacs; the funneling process is explained. To test as many aspects as possible of a fully integrated low-energy portion of a Pion generator for Medical Irradiation (PIGMI) Accelerator, a prototype accelerator was designed to take advantage of several pieces of existing accelerator hardware. The important principles to be tested in this prototype accelerator are detailed. Our prototype gyrocon has been extensively tested and modified; we discuss results from our investigations. Our work with the Fusion Materials Irradiation Test Facility is reviewed in this report.

Knapp, E.A.; Jameson, R.A. (comps.)

1982-05-01

294

Photon acceleration in laser wakefield accelerators  

SciTech Connect

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.

Trines, R. M. G. M. [CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX (United Kingdom)

2007-07-11

295

Physically Based Rendering Intersection Acceleration  

E-print Network

Physically Based Rendering (600.657) Intersection Acceleration #12;Intersection Testing Accelerated partitions: Group objects into clusters Cluster volumes may overlap #12;Uniform (Voxel) Grid Acceleration Acceleration · Trace rays through grid cells ­ Fast ­ Incremental A B C D E F Only check primitives

Kazhdan, Michael

296

Acceleration-resistant crystal resonator  

NASA Astrophysics Data System (ADS)

A crystal resonator features two crystals mounted such that the acceleration sensitivity vector of one crystal is in an antiparallel relationship to the acceleration sensitivity vector of the other crystal. The composite resonator eliminates acceleration-induced frequency shifts for acceleration in all directions.

Filler, R. L.

1983-10-01

297

Plasma-based accelerator structures  

SciTech Connect

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.

Schroeder, Carl B.

1999-12-01

298

Fermi acceleration in astrophysical jets  

E-print Network

We consider the acceleration of energetic particles by Fermi processes (i.e., diffusive shock acceleration, second order Fermi acceleration, and gradual shear acceleration) in relativistic astrophysical jets, with particular attention given to recent progress in the field of viscous shear acceleration. We analyze the associated acceleration timescales and the resulting particle distributions, and discuss the relevance of these processes for the acceleration of charged particles in the jets of AGNs, GRBs and microquasars, showing that multi-component powerlaw-type particle distributions are likely to occur.

Frank M. Rieger; Valenti Bosch-Ramon; Peter Duffy

2006-10-05

299

Microelectromechanical acceleration-sensing apparatus  

DOEpatents

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.

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

300

Acoustic particle acceleration sensors  

SciTech Connect

A crossed dipole array provides a directional receiving capability in a relatively small sensor package and is therefore very attractive for many applications in acoustics. Particle velocity measurements on two axes perpendicular to each other are required to provide the dipole signals. These can be obtained directly using particle velocity sensors or via simple transfer functions using acceleration and displacement sensors. Also, the derivative of the acoustic pressure with respect to space provides a signal proportional to the particle acceleration and gives rise to the pressure gradient sensor. Each of these sensors has strengths and drawbacks depending on the frequency regime of interest, the noise background, and whether a point or a line configuration of dipole sensors is desired. In this paper, the performance of acceleration sensors is addressed using a sensor concept developed at DREA. These sensors exploit bending stresses in a cantilever beam of piezoelectric material to obtain wide bandwidth and high sensitivity. Models which predict the acceleration sensitivity, pressure sensitivity, and natural frequency for this type of sensor are described. Experimental results obtained using several different versions of these sensors are presented and compared with theory. The predicted performance of acceleration sensors are compared with that of pressure gradient arrays and particle velocity sensors. {copyright} {ital 1996 American Institute of Physics.}

Franklin, J.B. [Franklin Scientific Services (work performed while Mr. Franklin was employed by Defence Research Establishment Atlantic); Barry, P.J. [Defence Research Establishment Atlantic, P.O. Box 1012, Dartmouth, B2Y 3Z7 (CANADA)

1996-04-01

301

Dielectric laser accelerators  

NASA Astrophysics Data System (ADS)

The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

2014-10-01

302

Negative hydrogen ion sources for accelerators  

SciTech Connect

A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systems to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.

Moehs, D.P.; /Fermilab; Peters, J.; /DESY; Sherman, J.; /Los Alamos

2005-08-01

303

Ernest Orlando Lawrence Berkeley National Laboratory 03/8/2001 E.O. Lawrence Berkeley National Laboratory  

E-print Network

, Accelerator & Fusion Research & Nuclear Science 50A Director's Office, Environment & Laboratory Development, Administration Division, Patents 50B Physics, Computer Center, IRD & ICSD 50C PID, Physics 50D MCSD & Nuclear Year 2000 Site Name: Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) Operation Office

304

Ernest Orlando Lawrence Berkeley National Laboratory 06/12/2000 E.O. Lawrence Berkeley National Laboratory  

E-print Network

, Accelerator & Fusion Research & Nuclear Science 50A Director's Office, Environment & Laboratory Development, Administration Division, Patents 50B Physics, Computer Center, IRD & ICSD 50C PID, Physics 50D MCSD & Nuclear Year 1999 Site Name: Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) Operation Office

305

Medical uses of accelerators  

SciTech Connect

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.

Bradbury, J.N.

1981-01-01

306

Perturbations for transient acceleration  

SciTech Connect

According to the standard ?CDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

Vargas, Cristofher Zuñiga; Zimdahl, Winfried [Universidade Federal do Espírito Santo, Departamento de Física, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo (Brazil); Hipólito-Ricaldi, Wiliam S., E-mail: win_unac@hotmail.com, E-mail: hipolito@ceunes.ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br [Universidade Federal do Espírito Santo, Departamento de Ciências Naturais, Grupo de Física Teórica, Rodovia BR 101 Norte, km 60, Campus de São Mateus, CEP 29932-540, São Mateus, Espírito Santo (Brazil)

2012-04-01

307

Diffusive Shock Acceleration  

NASA Astrophysics Data System (ADS)

The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. This statistical energization mechanism, manifested in turbulent media, was first posited by Enrico Fermi in 1949 to explain the observed cosmic ray population, which exhibits an almost power-law distribution in rigidity. The absence of a momentum scale is a key characteristic of diffusive shock acceleration, and astrophysical systems generally only impose scales at the injection (low energy) and loss (high energy) ends of the particle spectrum. The existence of structure in the cosmic ray spectrum (the "knee") at around 3000 TeV has promoted contentions that there are at least two origins for cosmic rays, a galactic one supplying those up to the knee, and perhaps an extragalactic one that can explain even the ultra-high energy cosmic rays (UHECRs) seen at 1-300 EeV. Accounting for the UHECRs with familiar astrophysical sites of acceleration has historically proven difficult due to the need to assume high magnetic fields in order to reduce the shortest diffusive acceleration timescale, the ion gyroperiod, to meaningful values. Yet active galaxies and gamma-ray bursts remain strong and interesting candidate sources for UHECRs, turning the theoretical focus to relativistic shocks. This review summarizes properties of diffusive shock acceleration that are salient to the issue of UHECR generation. These include spectral indices, anisotropies, acceleration efficencies and timescales, as functions of the shock speed and mean field orientation, and also the degree of field turbulence. Astrophysical sites for UHECR production are also critiqued.

Baring, Matthew

2003-04-01

308

Accelerated molecular dynamics methods  

SciTech Connect

The molecular dynamics method, although extremely powerful for materials simulations, is limited to times scales of roughly one microsecond or less. On longer time scales, dynamical evolution typically consists of infrequent events, which are usually activated processes. This course is focused on understanding infrequent-event dynamics, on methods for characterizing infrequent-event mechanisms and rate constants, and on methods for simulating long time scales in infrequent-event systems, emphasizing the recently developed accelerated molecular dynamics methods (hyperdynamics, parallel replica dynamics, and temperature accelerated dynamics). Some familiarity with basic statistical mechanics and molecular dynamics methods will be assumed.

Perez, Danny [Los Alamos National Laboratory

2011-01-04

309

A Smoother Acceleration  

NSDL National Science Digital Library

Some may argue that gifted children have many education options, but these options do not always help gifted students learn science. Unfortunately, gifted students often do not reach their full academic potential--they are frequently less motivated to succeed because they are not being academically challenged in regular classrooms (McCoach and Siegle 2003). To counter these problems, a strong option for educating gifted students is acceleration. This article describes the challenges that more and more gifted students face when accelerating, particularly when skipping an entire academic year. Strategies to lessen their intensity and duration and, ultimately, help gifted students to succeed are also included.

Chapman, Christine

2009-03-01

310

Interfacing to accelerator instrumentation  

SciTech Connect

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.

Shea, T.J.

1995-12-31

311

Photocathodes in accelerator applications  

SciTech Connect

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/sub 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.

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

1987-01-01

312

'Light Sail' Acceleration Reexamined  

SciTech Connect

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.

Macchi, Andrea [CNR/INFM/polyLAB, Pisa (Italy); Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); Veghini, Silvia; Pegoraro, Francesco [Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy)

2009-08-21

313

An accelerator technology legacy  

SciTech Connect

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.

Heighway, E.A.

1994-11-01

314

The international atomic energy agency's programme on utilization of accelerators  

NASA Astrophysics Data System (ADS)

Low-energy accelerators have in the past produced a major part of our current knowledge of nuclear physics. Today they are mainly used for applied research and industrial applications. In view of this, the International Atomic Energy Agency (IAEA) has during recent years initiated several Coordinated Research Projects (CRPs) concerning Ion Beam Analysis of Materials, Accelerator Mass Spectrometry and Nuclear Microprobe Techniques. The CRPs involve laboratories from developing as well as developed Member States, networking on a common topic coordinated by the IAEA. In order to facilitate networking, the IAEA has recently published the "World Survey of Accelerator Based Analytical Techniques" available on the Internet and as a CD-ROM. The IAEA maintains also a beamline at a 6 MV Van de Graaff accelerator in the Ru ?jer Bo\\vskovi? Institute, Zagreb, Croatia. Small and medium power accelerator driven spallation neutron sources will become more important as many small neutron producing research reactors are approaching the end of their useful working life. The IAEA has, within its Department for Nuclear Sciences and Applications, a programme on the Effective Utilization of Accelerators. This programme helps Member States, in particular developing Member States, in finding new areas of applications for their low and medium energy accelerators through increased participation in activities such as Coordinated Research Projects, Technical Meetings and Conferences. This paper describes the IAEA's current programme on accelerator utilization and proposed future activities.

Dytlewski, Nikolai; Mank, Günter; Rosengard, Ulf; Bamford, Samuel; Markowicz, Andrzej; Wegrzynek, Dariusz

2006-06-01

315

Space Experiments with Particle Accelerators (SEPAC)  

NASA Technical Reports Server (NTRS)

The purpose of Space Experiments with Particle Accelerators (SEPAC) on the Atmospheric Laboratory for Applications and Science (ATLAS 1) mission, is to carry out active and interactive experiments on and in the earth's ionosphere, atmosphere, and magnetosphere. The instruments to be used are an electron beam accelerator (EBA), plasma contactor, and associated instruments the purpose of which is to perform diagnostic, monitoring, and general data taking functions. Four major classes of investigations are to be performed by SEPAC. They are: beam plasma physics, beam-atmosphere interactions, the use of modulated electron beams as transmitting antennas, and the use of electron beams for remote sensing of electric and magnetic fields. The first class consists mainly of onboard plasma physics experiments to measure the effects of phenomena in the vicinity of the shuttle. The last three are concerned with remote effects and are supported by other ATLAS 1 investigations as well as by ground-based observations.

Obayashi, Tatsuzo

1988-01-01

316

Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1% per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/ps/mm{sup 2}, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within {+-}10%.

Nakamura, K.; Gonsalves, A. J.; Lin, C.; Sokollik, T.; Smith, A.; Rodgers, D.; Donahue, R.; Bryne, W.; Leemans, W. P. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)

2010-11-04

317

Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1percent per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm2 and 0.4 pC/ps/mm2, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within +/-10 percent.

Nakamura, K.; Gonsalves, A. J.; Lin, C.; Sokollik, T.; Smith, A.; Rodgers, D.; Donahue, R.; Bryne, W.; Leemans, W. P.

2010-06-01

318

Simulation of Electron Injection and Acceleration in Channel-Guided Laser Wakefield Accelerators  

NASA Astrophysics Data System (ADS)

The generation of high quality electron beams from a laser wakefield accelerator (LWFA) is expected to require external injection of electrons. Several all-optical electron injection schemes have been proposed and will be employed in upcoming LWFA experiments at the Naval Research Laboratory. Some of these schemes are theoretically capable of producing extremely short, precisely timed (phased) injected electron bunches. Simulations demonstrate that such ideal bunches may be accelerated by the LWFA to high energies with excellent beam emittance and small energy spread. Simulations using nonideal bunches with longer bunch length or energy spread have also been carried out. Some of these simulations show that phased, ultrashort injection may not be necessary for a high quality accelerated beam if the injected energy is carefully chosen. In these cases, the small energy spread and bunch length in the final accelerated beam is a result of removal (pruning) of electrons that move into defocusing portions of the wakefield, combined with strong phase bunching and rapid acceleration.

Hubbard, R. F.; Gordon, D. F.; Ting, A.; Sprangle, P.; Jones, T. G.; Zigler, A.; Hafizi, B.; Kaganovich, D.

2003-10-01

319

Load Schedule Coordination for a Large Linear Accelerator: An Operation Powerplay Concept  

E-print Network

-power from Federal power projects, and the Los Alamos National Laboratory (LANL) at Los Alamos, New Mexico. With this variation, only the portion of LANL's total load requirement for the Linear Accelerator at the Meson Physics Facility is targeted...

Johnson, W. H.

1984-01-01

320

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

SciTech Connect

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

Bakeman, M.S.; Van Tilborg, J.; Nakamura, K.; Gonsalves, A.; Osterhoff, J.; Sokollik, T.; Lin, C.; Robinson, K.E.; Schroeder, C.B.; Toth, Cs.; Weingartner, R.; Gruner, F.; Esarey, E.; Leemans, W.P.

2010-06-01

321

Acceleration of cheese ripening  

Microsoft Academic Search

The characteristic aroma, flavour and texture of cheese develop during ripening of the cheese curd through the action of numerous enzymes derived from the cheese milk, the coagulant, starter and non-starter bacteria. Ripening is a slow and consequently an expensive process that is not fully predictable or controllable. Consequently, there are economic and possibly technological incentives to accelerate ripening. The

P. F. Fox; J. M. Wallace; S. Morgan; C. M. Lynch; E. J. Niland; J. Tobin

1996-01-01

322

Radioisotope Dating with Accelerators.  

ERIC Educational Resources Information Center

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)

Muller, Richard A.

1979-01-01

323

Convergence Acceleration Techniques  

E-print Network

This work describes numerical methods that are useful in many areas: examples include statistical modelling (bioinformatics, computational biology), theoretical physics, and even pure mathematics. The methods are primarily useful for the acceleration of slowly convergent and the summation of divergent series that are ubiquitous in relevant applications. The computing time is reduced in many cases by orders of magnitude.

U. D. Jentschura; S. V. Aksenov; P. J. Mohr; M. A. Savageau; G. Soff

2003-11-18

324

Acceleration of Series  

E-print Network

The rate of convergence of infinite series can be accelerated b y a suitable splitting of each term into two parts and then combining the second part of the n-th term with the first part of the (n+1) -th term t get a new ...

Gosper, R.W.

1974-03-01

325

The Physics Hypertextbook: Acceleration  

NSDL National Science Digital Library

This online tutorial offers support in understanding acceleration from both a conceptual and a quantitative framework. It features a discussion of key concepts, practice problems with answers provided, and a list of links to related activities for high school students. This resource is part of an online textbook in introductory physics.

Elert, Glenn

2006-10-19

326

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

Detailed measurements of the axial velocity profile and electromagnetic structure of a high power, quasi-steady MPD discharge are used to formulate a gasdynamic model of the acceleration process. Conceptually dividing the accelerated plasma into an inner flow and an outer flow, it is found that more than two-thirds of the total power in the plasma is deposited in the inner flow, accelerating it to an exhaust velocity of 12.5 km/sec. The outer flow, which is accelerated to a velocity of only 6.2 km/sec, appears to provide a current conduction path between the inner flow and the anode. Related cathode studies have shown that the critical current for the onset of terminal voltage fluctuations, which was recently shown to be a function of the cathode area, appears to reach an asymptote for cathodes of very large surface area. Detailed floating potential measurements show that the fluctuations are confined to the vicinity of the cathode and hence reflect a cathode emission process rather than a fundamental limit on MPD performance.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1974-01-01

327

Duff's Acceleration Apparatus  

NASA Astrophysics Data System (ADS)

Some years ago I wrote a note about Packard's apparatus to honor an early physics teacher who designed apparatus. In this note I honor Dr. A. Wilmer Duff of Worchester Polytechnic Institute in Worchester, Mass., for his development of a simple and inexpensive method of studying uniformly accelerated motion.

Greenslade, Thomas B.

2003-03-01

328

ACCELERATOR COMPUTING INFRASTRUCTURE  

E-print Network

to the storing and presentation of all project documents, cads, etc; implementation and maintenance of a Project to the project. In the mean time, the international community interested in the development of the accelerator, FLUKA, GEANT, MCNPX,ANSYS · Controls R&D: Labview, memcache, mongoDB, etc · hardware has been installed

Istituto Nazionale di Fisica Nucleare (INFN)

329

Stacked insulator induction accelerator gaps  

SciTech Connect

Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

1997-05-01

330

Ambipolar ion acceleration in an expanding magnetic nozzle  

Microsoft Academic Search

The helicon plasma stage in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) VX-200i device was used to characterize an axial plasma potential profile within an expanding magnetic nozzle region of the laboratory based device. The ion acceleration mechanism is identified as an ambipolar electric field produced by an electron pressure gradient, resulting in a local axial ion speed of Mach

Benjamin W. Longmier; Edgar A. Bering III; Mark D. Carter; Leonard D. Cassady; William J. Chancery; Franklin R. Chang Díaz; Tim W. Glover; Noah Hershkowitz; Andrew V. Ilin; Greg E. McCaskill; Chris S. Olsen; Jared P. Squire

2011-01-01

331

New and old accelerators: what can they do for astrophysics  

SciTech Connect

The quantum numbers and energy spectrum of high energy accelerators and storage rings are described, along with some ways they may contribute to astrophysical issues. Some emphasis is given to the role of relativistic heavy-ion colliders in possibly providing laboratory samples of quark-gluon plasma. 6 refs., 3 figs.

Bjorken, J.D.

1985-07-01

332

Accelerator Mass Spectrometry in Biology and Health Care  

NSDL National Science Digital Library

This video, developed at Lawrence Livermore National Laboratory, describes the instrumentation for accelerator mass spectrometry and its applications. The content describes the instrumentation and its application for carbon dating and measurements of drug distribution. Running time for the video is 49:31.

333

Development of ADS virtual accelerator based on XAL  

NASA Astrophysics Data System (ADS)

XAL is a high level accelerator application framework that was originally developed by the Spallation Neutron Source (SNS), Oak Ridge National Laboratory. It has an advanced design concept and has been adopted by many international accelerator laboratories. Adopting XAL for ADS is a key subject in the long term. This paper will present the modifications to the original XAL applications for ADS. The work includes a proper relational database schema modification in order to better suit the requirements of ADS configuration data, redesigning and re-implementing db2xal application, and modifying the virtual accelerator application. In addition, the new device types and new device attributes for ADS online modeling purpose are also described here.

Wang, Peng-Fei; Cao, Jian-She; Ye, Qiang

2014-07-01

334

Design of accelerated corrosion tests for electronic components in automotive applications  

Microsoft Academic Search

Two new accelerated laboratory corrosion tests for electronic components in automotive applications have been developed, based on the use of metallic copper as a meter for corrosivity. The accelerated tests are designed so that they reproduce the same kind of corrosion effects as observed with exposure of copper in real vehicle environments. The test cycle that best simulates the corrosion

Peter Eriksson; Bo Carlsson; I. O. Wallinder

2001-01-01

335

Drive Beam Shaping and Witness Bunch Generation for the Plasma Wakefield Accelerator  

NASA Astrophysics Data System (ADS)

High transformer ratio operation of the plasma wake field accelerator requires a tailored drive beam current profile followed by a short witness bunch. We discuss techniques for generating the requisite dual bunches and for obtaining the desired drive beam profile, with emphasis on the FACET experiment at SLAC National Accelerator Laboratory.

England, R. J.; Frederico, J.; Hogan, M. J.; Muggli, P.; Joshi, C.

2010-11-01

336

When Is a Laboratory a Laboratory?  

ERIC Educational Resources Information Center

Gives advice on the legal necessity of safety planning for school science (or other) laboratories. Recommends looking into governmental definitions of the term "laboratory" to determine which educational activities should be covered by safety planning. (WRM)

Roy, Ken

1999-01-01

337

Accelerator and transport line survey and alignment  

SciTech Connect

This paper summarizes the survey and alignment processes of accelerators and transport lines and discusses the propagation of errors associated with these processes. The major geodetic principles governing the survey and alignment measurement space are introduced and their relationship to a lattice coordinate system shown. The paper continues with a broad overview about the activities involved in the step sequence from initial absolute alignment to final smoothing. Emphasis is given to the relative alignment of components, in particular to the importance of incorporating methods to remove residual systematic effects in surveying and alignment operations. Various approaches to smoothing used at major laboratories are discussed. 47 refs., 19 figs., 1 tab.

Ruland, R.E.

1991-10-01

338

Nighttime Clouds in Martian Arctic (Accelerated Movie)  

NASA Technical Reports Server (NTRS)

An angry looking sky is captured in a movie clip consisting of 10 frames taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander.

The clip accelerates the motion. The images were take around 3 a.m. local solar time at the Phoenix site during Sol 95 (Aug. 30), the 95th Martian day since landing.

The swirling clouds may be moving generally in a westward direction over the lander.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

339

Acceleration and Classical Electromagnetic Radiation  

E-print Network

Classical radiation from an accelerated charge is reviewed along with the reciprocal topic of accelerated observers detecting radiation from a static charge. This review commemerates Bahram Mashhoon's 60th birthday.

E. N. Glass

2008-01-09

340

Dust accelerators and their applications in high-temperature plasmas  

SciTech Connect

The perennial presence of dust in high-temperature plasma and fusion devices has been firmly established. Dust inventory must be controlled, in particular in the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and potentially interfere with fusion energy production. Much effort has been devoted to gening rid of the dust nuisance. We have recognized a number of dust-accelerators applications in magnetic fusion, including in plasma diagnostics, in studying dust-plasma interactions, and more recently in edge localized mode (ELM)'s pacing. With the applications in mind, we will compare various acceleration methods, including electrostatic, gas-drag, and plasma-drag acceleration. We will also describe laboratory experiments and results on dust acceleration.

Wang, Zhehui [Los Alamos National Laboratory; Ticos, Catakin M [NILPRP, ROMANIA

2010-01-01

341

A plasma wakefield acceleration experiment using CLARA beam  

NASA Astrophysics Data System (ADS)

We propose a Plasma Accelerator Research Station (PARS) based at proposed FEL test facility CLARA (Compact Linear Accelerator for Research and Applications) at Daresbury Laboratory. The idea is to use the relativistic electron beam from CLARA, to investigate some key issues in electron beam transport and in electron beam driven plasma wakefield acceleration, e.g. high gradient plasma wakefield excitation driven by a relativistic electron bunch, two bunch experiment for CLARA beam energy doubling, high transformer ratio, long bunch self-modulation and some other advanced beam dynamics issues. This paper presents the feasibility studies of electron beam transport to meet the requirements for beam driven wakefield acceleration and presents the plasma wakefield simulation results based on CLARA beam parameters. Other possible experiments which can be conducted at the PARS beam line are also discussed.

Xia, G.; Angal-Kalinin, D.; Clarke, J.; Smith, J.; Cormier-Michel, E.; Jones, J.; Williams, P. H.; Mckenzie, J. W.; Militsyn, B. L.; Hanahoe, K.; Mete, O.; Aimidula, A.; Welsch, C. P.

2014-03-01

342

Solvent-free cleaning using a centrifugal cryogenic pellet accelerator  

SciTech Connect

An advanced centrifuge that accelerates frozen CO{sub 2} pellets to high speeds for surface cleaning and paint removal is being developed at the Oak Ridge National Laboratory. The centrifuge-based accelerator was designed, fabricated, and tested under a program sponsored by the Warner Robins Air Logistics Center, Robins Air Force Base, Georgia. In comparison to the more conventional compressed air ``sandblast`` pellet accelerators, the centrifugal accelerator system can achieve higher pellet speeds, has precise speed control, and is more than ten times as energy efficient. Furthermore, the use of frozen CO{sub 2} pellets instead of conventional metal, plastic, sand, or other abrasive materials that remain solid at room temperature, minimizes the waste stream. This apparatus has been used to demonstrate cleaning of various surfaces, including removal of paint, oxide coatings, metal coatings, organic coatings, and oil and grease coatings from a variety of surfaces. The design and operation of the apparatus is discussed.

Haines, J.R.; Fisher, P.W.; Foster, C.A.

1995-06-01

343

Dust Accelerators And Their Applications In High-Temperature Plasmas  

NASA Astrophysics Data System (ADS)

The perennial presence of dust in high-temperature plasma and fusion devices has been firmly established. Dust inventory must be controlled, in particular in the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and potentially interfere with fusion energy production. Although much effort has been devoted to getting rid of the dust nuisance, there are instances where a controlled use of dust can be beneficial. We have recognized a number of dust-accelerators applications in magnetic fusion, including in plasma diagnostics, in studying dust-plasma interactions, and more recently in edge localized mode (ELM)'s pacing. With the applications in mind, we will compare various acceleration methods, including electrostatic, gas-drag, and plasma-drag acceleration. We will also describe laboratory experiments and results on dust acceleration.

Tico?, C?t?lin M.; Wang, Zhehui

2011-06-01

344

Constellation Acceleration Study December 18, 2008  

E-print Network

Constellation Acceleration Study Report December 18, 2008 #12;Constellation Acceleration Study ........................................................................................................... 31 #12;Constellation Acceleration Study Report 12/18/08 Executive Summary In 2004, the White House

Christian, Eric

345

Particle Acceleration at Relativistic Shocks  

E-print Network

I review the current status of Fermi acceleration theory at relativistic shocks. I first discuss the relativistic shock jump conditions, then describe the non-relativistic Fermi mechanism and the differences introduced by relativistic flows. I present numerical calculations of the accelerated particle spectrum, and examine the maximum energy attainable by this process. I briefly consider the minimum energy for Fermi acceleration, and a possible electron pre-acceleration mechanism.

Yves A. Gallant

2002-01-15

346

Principles of Charged Particle Acceleration  

NSDL National Science Digital Library

This learning resources comprise a healthy introduction to charged particle acceleration. The site, by Stanley Humphries, a professor of electrical and computer engineering at University of New Mexico, amounts to an online textbook (.pdf) introducing the theory of charged particle acceleration. The book's fifteen chapters (with bibliography) summarize "the principles underlying all particle accelerators" and provide "a reference collection of equations and material essential to accelerator development and beam applications."

2007-05-03

347

Exploring Acceleration with an Android  

NSDL National Science Digital Library

Students conduct an experiment to study the acceleration of a mobile Android device. During the experiment, they run an application created with MIT's App Inventor that monitors linear acceleration in one-dimension. Students use an acceleration vs. time equation to construct an approximate velocity vs. time graph. Students will understand the relationship between the object's mass and acceleration and how that relates to the force applied to the object, which is Newton's second law of motion.

IMPART RET Program, College of Information Science & Technology,

348

Chemistry Laboratory Safety Check  

ERIC Educational Resources Information Center

An accident prevention/safety check list for chemistry laboratories is printed. Included are checks of equipment, facilities, storage and handling of chemicals, laboratory procedures, instruction procedures, and items to be excluded from chemical laboratories. (SL)

Patnoe, Richard L.

1976-01-01

349

Acceleration in de Sitter spacetimes  

E-print Network

We propose a definition of uniform accelerated frames in de Sitter spacetimes exploiting the Nachtmann group theoretical method of introducing coordinates on these manifolds. Requiring the transformation between the static frame and the accelerated one to depend continuously on acceleration in order to recover the well-known Rindler approach in the flat limit, we obtain a new metric with a reasonable physical meaning.

Ion I. Cotaescu

2014-07-11

350

I Investigation of Pellet Acceleration  

E-print Network

I Investigation of Pellet Acceleration by an Arc heated Gas Gun An Interim Report INVESTIGATION OP PELLET ACCELERATION BY AN ARC HEATED GAS GUN* An Interim Report on the Investigations carried above those obtained so far. An experimental setup designed for a study of acceleration of 3 mm0 pellets

351

Accelerator research studies  

SciTech Connect

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.

Not Available

1992-01-01

352

Review of ion accelerators  

SciTech Connect

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.

Alonso, J.

1990-06-01

353

Hypervelocity plate acceleration  

SciTech Connect

Shock tubes have been used to accelerate 1.5-mm-thick stainless steel plates to high velocity while retaining their integrity. The fast shock tubes are 5.1-cm-diameter, 15.2-cm-long cylinders of PBX-9501 explosive containing a 1.1-cm-diameter cylindrical core of low-density polystyrene foam. The plates have been placed directly in contact with one face of the explosive system. Plane-wave detonation was initiated on the opposite face. A Mach disk was formed in the imploding styrofoam core, which provided the impulse required to accelerate the metal plate to high velocity. Parametric studies were made on this system to find the effect of varying plate metal, plate thickness, foam properties, and addition of a barrel. A maximum plate velocity of 9.0 km/s has been observed. 6 refs., 17 figs.

Marsh, S.P.; Tan, T.H.

1991-01-01

354

Accelerometer: Centripetal Acceleration  

NSDL National Science Digital Library

Students work as physicists to understand centripetal acceleration concepts. They also learn about a good robot design and the accelerometer sensor. They also learn about the relationship between centripetal acceleration and centripetal force—governed by the radius between the motor and accelerometer and the amount of mass at the end of the robot's arm. Students graph and analyze data collected from an accelerometer, and learn to design robots with proper weight distribution across the robot for their robotic arms. Upon using a data logging program, they view their own data collected during the activity. By activity end , students understand how a change in radius or mass can affect the data obtained from the accelerometer through the plots generated from the data logging program. More specifically, students learn about the accuracy and precision of the accelerometer measurements from numerous trials.

2014-09-18

355

Review of accelerator instrumentation  

SciTech Connect

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.

Pellegrin, J.L.

1980-05-01

356

Adaptive control for accelerators  

DOEpatents

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.

Eaton, Lawrie E. (Los Alamos, NM); Jachim, Stephen P. (Los Alamos, NM); Natter, Eckard F. (Santa Fe, NM)

1991-01-01

357

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

Experimental data were combined with one-dimensional conservation relations to yield information on the energy deposition ratio in a parallel-plate accelerator, where the downstream flow was confined to a constant area channel. Approximately 70% of the total input power was detected in the exhaust flow, of which only about 20% appeared as directed kinetic energy, thus implying that a downstream expansion to convert chamber enthalpy into kinetic energy must be an important aspect of conventional high power MPD arcs. Spectroscopic experiments on a quasi-steady MPD argon accelerator verified the presence of A(III) and the absence of A(I), and indicated an azimuthal structure in the jet related to the mass injection locations. Measurements of pressure in the arc chamber and impact pressure in the exhaust jet using a piezocrystal backed by a Plexiglas rod were in good agreement with the electromagnetic thrust model.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1971-01-01

358

An accelerated closed universe  

E-print Network

We study a model in which a closed universe with dust and quintessence matter components may look like an accelerated flat Friedmann-Robertson-Walker (FRW) universe at low redshifts. Several quantities relevant to the model are expressed in terms of observed density parameters, $\\Omega_M$ and $\\Omega_{\\Lambda}$, and of the associated density parameter $\\Omega_Q$ related to the quintessence scalar field $Q$.

Sergio del Campo; Mauricio Cataldo; Francisco Pena

2004-08-03

359

Accelerator simulation using computers  

SciTech Connect

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.

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

1992-01-01

360

Accelerator simulation using computers  

SciTech Connect

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.

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

1992-01-01

361

Progress of RIBF accelerators  

NASA Astrophysics Data System (ADS)

In order to greatly expand scientific opportunities with radioactive isotope (RI) beams, RIKEN has constructed a new heavy-ion accelerator facility, called "RI Beam Factory (RIBF)." Three new ring cyclotrons with K-values of 570 MeV, 980 MeV, and 2600 MeV, respectively, boost the energies of the output beams from the existing K540-MeV ring cyclotron up to 440 MeV/u for light ions and 345 MeV/u for very heavy ions. These energetic heavy-ion beams are converted into intense radioactive isotope (RI) beams via projectile fragmentation of stable isotopes or in-flight fission of uranium isotopes by a superconducting fragment separator, BigRIPS. The three ring cyclotrons were commissioned in 2006, and RI beams from uranium were first obtained in 2007. The beam intensities and available ion species are increasing at RIBF, owing to the continuous efforts that have been made since the first beam. So far, we have accelerated deuteron, helium, nitrogen, oxygen, aluminum, calcium, zinc, krypton, xenon, and uranium beams with the superconducting ring cyclotron (SRC). The extracted beam intensities reached 1000 pnA for the helium and oxygen beams, and the calcium beam intensity exceeded 400 pnA recently. The intensities of the xenon and uranium beams are also increasing; they reached 24 and 3.6 pnA, respectively. This paper illustrates the construction, commissioning, and various improvements carried out for the RIBF accelerators, as well as the present accelerator performance.

Okuno, H.; Fukunishi, N.; Kamigaito, O.

2012-12-01

362

Particle Acceleration Mechanisms  

Microsoft Academic Search

In this paper we review the possible mechanisms for production of non-thermal electrons which are responsible for the observed\\u000a non-thermal radiation in clusters of galaxies. Our primary focus is on non-thermal Bremsstrahlung and inverse Compton scattering,\\u000a that produce hard X-ray emission. We first give a brief review of acceleration mechanisms and point out that in most astrophysical\\u000a situations, and in

V. Petrosian; A. M. Bykov

2008-01-01

363

GPU accelerated dislocation dynamics  

NASA Astrophysics Data System (ADS)

In this paper we analyze the computational bottlenecks in discrete dislocation dynamics modeling (associated with segment-segment interactions as well as the treatment of free surfaces), discuss the parallelization and optimization strategies, and demonstrate the effectiveness of Graphical Processing Unit (GPU) computation in accelerating dislocation dynamics simulations and expanding their scope. Individual algorithmic benchmark tests as well as an example large simulation of a thin film are presented.

Ferroni, Francesco; Tarleton, Edmund; Fitzgerald, Steven

2014-09-01

364

Linear induction accelerator  

DOEpatents

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.

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

1988-06-21

365

A review of accelerator concepts for the Advanced Hydrotest Facility  

SciTech Connect

The Advanced Hydrotest Facility (AHF) is a facility under consideration by the Department of Energy (DOE) for conducting explosively-driven hydrodynamic experiments. The major diagnostic tool at AHF will be a radiography accelerator having radiation output capable of penetrating very dense dynamic objects on multiple viewing axes with multiple pulses on each axis, each pulse having a time resolution capable of freezing object motion ({approx}50-ns) and achieving a spatial resolution {approx}1 mm at the object. Three accelerator technologies are being considered for AHF by the DOE national laboratories at Los Alamos (LANL), Livermore (LLNL), and Sandia (SNL). Two of these are electron accelerators that will produce intense x-ray pulses from a converter target yielding a dose {approx}1,000--2,000 Rads {at} 1 meter. LLNL has proposed a 16--20 MeV, 3--6 kA linear induction accelerator (LIA) driven by FET-switched modulators driving metglas loaded cavities. SNL has proposed a 12-MeV, 40-kA Inductive Voltage Adder (IVA) accelerator based on HERMES III pulsed power technology. The third option is a 25--50-GeV proton accelerator capable of {approx}10{sup 13} protons/pulse proposed by LANL. This paper will review the current status of the three accelerator concepts for AHF.

Toepfer, A.J. [Science Applications International Corp., Albuquerque, NM (United States)

1998-08-01

366

Effects of Horizontal Acceleration on Human Visual Acuity and Stereopsis  

PubMed Central

The effect of horizontal acceleration on human visual acuity and stereopsis is demonstrated in this study. Twenty participants (mean age 22.6 years) were enrolled in the experiment. Acceleration from two different directions was performed at the Taiwan High-Speed Rail Laboratory. Gx and Gy (< and >0.1 g) were produced on an accelerating platform where the subjects stood. The visual acuity and stereopsis of the right eye were measured before and during the acceleration. Acceleration <0.1 g in the X- or Y-axis did not affect dynamic vision and stereopsis. Vision decreased (mean from 0.02 logMAR to 0.25 logMAR) and stereopsis declined significantly (mean from 40 s to 60.2 s of arc) when Gx > 0.1 g. Visual acuity worsened (mean from 0.02 logMAR to 0.19 logMAR) and poor stereopsis was noted (mean from 40 s to 50.2 s of arc) when Gy > 0.1 g. The effect of acceleration from the X-axis on the visual system was higher than that from the Y-axis. During acceleration, most subjects complained of ocular strain when reading. To our knowledge, this study is the first to report the exact levels of visual function loss during Gx and Gy. PMID:25607601

Horng, Chi-Ting; Hsieh, Yih-Shou; Tsai, Ming-Ling; Chang, Wei-Kang; Yang, Tzu-Hung; Yauan, Chien-Han; Wang, Chih-Hung; Kuo, Wu-Hsien; Wu, Yi-Chang

2015-01-01

367

Effects of horizontal acceleration on human visual acuity and stereopsis.  

PubMed

The effect of horizontal acceleration on human visual acuity and stereopsis is demonstrated in this study. Twenty participants (mean age 22.6 years) were enrolled in the experiment. Acceleration from two different directions was performed at the Taiwan High-Speed Rail Laboratory. Gx and Gy (< and >0.1 g) were produced on an accelerating platform where the subjects stood. The visual acuity and stereopsis of the right eye were measured before and during the acceleration. Acceleration <0.1 g in the X- or Y-axis did not affect dynamic vision and stereopsis. Vision decreased (mean from 0.02 logMAR to 0.25 logMAR) and stereopsis declined significantly (mean from 40 s to 60.2 s of arc) when Gx > 0.1 g. Visual acuity worsened (mean from 0.02 logMAR to 0.19 logMAR) and poor stereopsis was noted (mean from 40 s to 50.2 s of arc) when Gy > 0.1 g. The effect of acceleration from the X-axis on the visual system was higher than that from the Y-axis. During acceleration, most subjects complained of ocular strain when reading. To our knowledge, this study is the first to report the exact levels of visual function loss during Gx and Gy. PMID:25607601

Horng, Chi-Ting; Hsieh, Yih-Shou; Tsai, Ming-Ling; Chang, Wei-Kang; Yang, Tzu-Hung; Yauan, Chien-Han; Wang, Chih-Hung; Kuo, Wu-Hsien; Wu, Yi-Chang

2015-01-01

368

Accelerating QDP++ using GPUs  

E-print Network

Graphic Processing Units (GPUs) are getting increasingly important as target architectures in scientific High Performance Computing (HPC). NVIDIA established CUDA as a parallel computing architecture controlling and making use of the compute power of GPUs. CUDA provides sufficient support for C++ language elements to enable the Expression Template (ET) technique in the device memory domain. QDP++ is a C++ vector class library suited for quantum field theory which provides vector data types and expressions and forms the basis of the lattice QCD software suite Chroma. In this work accelerating QDP++ expression evaluation to a GPU was successfully implemented leveraging the ET technique and using Just-In-Time (JIT) compilation. The Portable Expression Template Engine (PETE) and the C API for CUDA kernel arguments were used to build the bridge between host and device memory domains. This provides the possibility to accelerate Chroma routines to a GPU which are typically not subject to special optimisation. As an application example a smearing routine was accelerated to execute on a GPU. A significant speed-up compared to normal CPU execution could be measured.

Frank Winter

2011-05-11

369

Oxidised cosmic acceleration  

SciTech Connect

We give detailed proofs of several new no-go theorems for constructing flat four-dimensional accelerating universes from warped dimensional reduction. These new theorems improve upon previous ones by weakening the energy conditions, by including time-dependent compactifications, and by treating accelerated expansion that is not precisely de Sitter. We show that de Sitter expansion violates the higher-dimensional null energy condition (NEC) if the compactification manifold M is one-dimensional, if its intrinsic Ricci scalar R-ring vanishes everywhere, or if R-ring and the warp function satisfy a simple limit condition. If expansion is not de Sitter, we establish threshold equation-of-state parameters w below which accelerated expansion must be transient. Below the threshold w there are bounds on the number of e-foldings of expansion. If M is one-dimensional or R-ring everywhere vanishing, exceeding the bound implies the NEC is violated. If R-ring does not vanish everywhere on M, exceeding the bound implies the strong energy condition (SEC) is violated. Observationally, the w thresholds indicate that experiments with finite resolution in w can cleanly discriminate between different models which satisfy or violate the relevant energy conditions.

Wesley, Daniel H., E-mail: D.H.Wesley@damtp.cam.ac.uk [Centre for Theoretical Cosmology, DAMTP, Cambridge University, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

2009-01-15

370

Accelerated Profile HMM Searches.  

PubMed

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. PMID:22039361

Eddy, Sean R

2011-10-01

371

Equipartitioning in linear accelerators  

SciTech Connect

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.

Jameson, R.A.

1981-01-01

372

Accelerated Profile HMM Searches  

PubMed Central

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. PMID:22039361

Eddy, Sean R.

2011-01-01

373

Uniqueness of current cosmic acceleration  

SciTech Connect

One of the strongest arguments against the cosmological constant as an explanation of the current epoch of accelerated cosmic expansion is the existence of an earlier, dynamical acceleration, i.e. inflation. We examine the likelihood that acceleration is an occasional phenomenon, putting stringent limits on the length of any accelerating epoch due to minimally coupled dark energy between recombination and the recent acceleration; such an epoch must last less than 0.05 e-fold (at z>2) or the matter power spectrum is modified by more than 20%.

Linder, Eric V. [Berkeley Lab and University of California, Berkeley, California 94720 (United States) and Institute for the Early Universe, Ewha Womans University, Seoul (Korea, Republic of)

2010-09-15

374

Radiographic testing at Lawrence Livermore National Laboratory  

SciTech Connect

Radiographic testing is a nondestructive inspection technique which uses penetrating radiation. The Nondestructive Evaluation (NDE) Section at Lawrence Livermore National Laboratory has a broad spectrum of equipment and techniques for radiographic testing. These resources include low-energy vacuum systems, low- and mid-energy cabinet and cell radiographic systems, high-energy linear accelerators, portable x-ray machines and radioisotopes for radiographic inspections. For diagnostic testing the NDE Section also has real-time and flash radiographic equipment.

Bossi, R.H.

1982-04-21

375

Muon Acceleration - RLA and FFAG  

SciTech Connect

Various acceleration schemes for muons are presented. The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and 'beam shaping' can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a non-scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain across the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. The RLAs offer very efficient usage of high gradient superconducting RF and ability to adjust path-length after each linac pass through individual return arcs with uniformly periodic FODO optics suitable for chromatic compensation of emittance dilution with sextupoles. However, they require spreaders/recombiners switchyards at both linac ends and significant total length of the arcs. The non-scaling Fixed Field Alternating Gradient (FFAG) ring combines compactness with very large chromatic acceptance (twice the injection energy) and it allows for large number of passes through the RF (at least eight, possibly as high as 15).

Alex Bogacz

2011-10-01

376

Recent Advances in Plasma Acceleration  

SciTech Connect

The costs and the time scales of colliders intended to reach the energy frontier are such that it is important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators a drive beam, either laser or particle, produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultra-high accelerating fields over a substantial length to achieve a significant energy gain. More than 42 GeV energy gain was achieved in an 85 cm long plasma wakefield accelerator driven by a 42 GeV electron drive beam in the Final Focus Test Beam (FFTB) Facility at SLAC. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx}52 GV/m. This effectively doubles their energy, producing the energy gain of the 3 km long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. Prospects for a drive-witness bunch configuration and high-gradient positron acceleration experiments planned for the SABER facility will be discussed.

Hogan, Mark

2007-03-19

377

Acceleration in Linear and Circular Motion  

ERIC Educational Resources Information Center

Describes the construction of a simple accelerometer and explains its use in demonstrating acceleration, deceleration, constant speed, measurement of acceleration, acceleration and the inclined plane and angular and radial acceleration. (GS)

Kellington, S. H.; Docherty, W.

1975-01-01

378

BotEC: Spacecraft Acceleration  

NSDL National Science Digital Library

Question Suppose someone offered you a ride to the nearest star in a new spacecraft that could travel at half the speed of light, or about 150,000 km/second. In order to reach such a cruising speed, you and the spacecraft must accelerate from a standstill to half the speed of light. Acceleration means uncomfortable (and maybe even fatal!) "g" forces, that pressed-into-the-seat feeling you get when a car or airplane accelerates. More than 3 g's of acceleration are tough to take for very long, so your spacecraft's engines are designed to accelerate you at not more than 29 meters/second/second (3 times the acceleration due to gravity at the Earth's surface). How long will it take you and your spacecraft to accelerate to half light speed?

Barb Tewksbury

379

Tevatron Run II Series at the Enrico Fermi Laboratory (USA)  

Microsoft Academic Search

The Run II Tevatron series at the Enrico Fermi Laboratory was started in March 2001. Numerous improvements to the accelerator complex were made in order to ensure operation of the proton–antiproton Tevatron accelerator with peak luminosity (2–4)·1032 cm–2·sec–1 and to obtain a total luminosity above 5 fb–1 before the LHC physical program starts. The current status of the Run II

R. Moore

2002-01-01

380

Testing a combined vibration and acceleration environment.  

SciTech Connect

Sandia National Laboratories has previously tested a capability to impose a 7.5 g-rms (30 g peak) radial vibration load up to 2 kHz on a 25 lb object with superimposed 50 g acceleration at its centrifuge facility. This was accomplished by attaching a 3,000 lb Unholtz-Dickie mechanical shaker at the end of the centrifuge arm to create a 'Vibrafuge'. However, the combination of non-radial vibration directions, and linear accelerations higher than 50g's are currently not possible because of the load capabilities of the shaker and the stresses on the internal shaker components due to the combined centrifuge acceleration. Therefore, a new technique using amplified piezo-electric actuators has been developed to surpass the limitations of the mechanical shaker system. They are lightweight, modular and would overcome several limitations presented by the current shaker. They are 'scalable', that is, adding more piezo-electric units in parallel or in series can support larger-weight test articles or displacement/frequency regimes. In addition, the units could be mounted on the centrifuge arm in various configurations to provide a variety of input directions. The design along with test results will be presented to demonstrate the capabilities and limitations of the new piezo-electric Vibrafuge.

Jepsen, Richard Alan; Romero, Edward F.

2005-01-01

381

Modeling of Electron Injection and Acceleration in NRL Laser Wakefield Accelerator Experiments  

NASA Astrophysics Data System (ADS)

The Naval Research Laboratory (NRL) is carrying out a series of optical injection and acceleration experiments using intense, short pulse lasers and gas jets or capillary discharge plasma channels. This paper describes modeling of these experiments using the turboWAVE and WAKE simulation codes. Recent experiments using the 400 fsec T3 laser have employed two gas jets and separate laser pulses and have successfully demonstrated optical injection of moderate energy electrons followed by unguided, self-modulated LWFA acceleration of these electrons to >10 MeV. Simulations confirm that a portion of the injected electron spectrum can be trapped and accelerated to high energies in the second stage. A second laser system, the Ti:sapphire TFL laser, is currently being upgraded and will be used for channel-guided LWFA experiments in the short pulse (standard) regime. Simulations and Hamiltonian analysis predict that high quality accelerated electron beams are possible with such a system even if the injected electron bunch has a large energy spread.

Hubbard, R. F.; Gordon, D. F.; Cooley, J. H.; Ting, A.; Sprangle, P.; Jones, T. G.; Zigler, A.; Kaganovich, D.

2004-11-01

382

Laser Ion Acceleration Using Few Times Critical Density Plasma  

NASA Astrophysics Data System (ADS)

The generation of high energy ions by means of high intensity laser irradiation of solid targets has been a subject of active research for over a decade. More recently, experimental groups at both Brookhaven National Laboratory and UCLA have shown ion acceleration using CO2 lasers interacting with gas jets that, when ionized, yield plasma densities that are a few times critical density. The advantages of such targets are that they are relatively simple and can be easily operated at high repetition rates. The physics that drive this type of acceleration is not yet well understood. Of particular interest is the scaling of such acceleration to various laser pulse parameters (including multiple pulses) and the effect of the longitudinal plasma density profile on the acceleration process. Additionally, since the plasma is only a few times critical density, frequency upshifted radiation is able to propagate deeper into the target which could lead to interesting new physics in itself. We will discuss various methods of extending this type of acceleration to optical wavelength and present fully 3D simulations as well as preliminary experimental results conducted at the Naval Research Laboratory.

Helle, Michael; Gordon, Daniel; Kaganovich, Dmitri; Ting, Antonio

2011-11-01

383

Accelerator Technology Program. Progress report, January-June 1980  

SciTech Connect

The activities of Los Alamos Scientific Laboratory's (LASL) Accelerator Technology (AT) Division during the first six months of calendar 1980 are discussed. This report is organized around major projects of the Division, reflecting a wide variety of applications and sponsors. The first section summarizes progress on the Proton Storage Ring to be located between LAMPF and the LASL Pulsed Neutron Research facility, followed by a section on the gyrocon, a new type of high-power, high-efficiency radio-frequency (rf) amplifier. The third section discusses the racetrack microtron being developed jointly by AT Division and the National Bureau of Standards; the fourth section concerns the free-electron studies. The fifth section covers the radio-frequency quadrupole linear accelerator, a new concept for the acceleration of low-velocity particles; this section is followed by a section discussing heavy ion fusion accelerator development. The next section reports activities in the Fusion Materials Irradiation Test program, a collaborative effort with the Hanford Engineering Development Laboratory. The final section deals first with development of H/sup -/ ion sources and injectors, then with accelerator instrumentation and beam dynamics.

Knapp, E.A.; Jameson, R.A. (Comps.)

1980-03-01

384

Annual Report Alfvn Laboratory  

E-print Network

Annual Report 2004 Alfvén Laboratory Alfvén Laboratory RoyalInstitute ofTechnology SE 100 44 Stockholm #12;Alfvén Laboratory Annual Report 2004 i ANNUAL REPORT 2004 Alfvén Laboratory Royal Institute Annual Report 2004 ii CONTENTS Appendix A Detailed Report from the Division of Plasma Physics Section

Haviland, David

385

Ion Accelerator With Negatively Biased Decelerator Grid  

NASA Technical Reports Server (NTRS)

Three-grid ion accelerator in which accelerator grid is biased at negative potential and decelerator grid downstream of accelerator grid biased at smaller negative potential. This grid and bias arrangement reduces frequency of impacts, upon accelerator grid, of charge-exchange ions produced downstream in collisions between accelerated ions and atoms and molecules of background gas. Sputter erosion of accelerator grid reduced.

Brophy, John R.

1994-01-01

386

ELECTRON INJECTION INTO CYCLIC ACCELERATOR USING  

E-print Network

­ accelerating light, 5 ­ accelerated electrons, 6 ­fast kicker - + accelerating laser pulse evaporatinglaser due to scattering on evaporated gas atoms u u 1- evaporating light, 2 ­ accelerating light, 3 ­ MgELECTRON INJECTION INTO CYCLIC ACCELERATOR USING LASER WAKEFIELD ACCELERATION Ya. V. Getmanov, O. A

387

Accelerating Venture Creation and Building on Mutual Strengths in Experimental Business Labs  

ERIC Educational Resources Information Center

This paper articulates the opportunity of using an experimental business laboratory approach as a means of accelerating the creation, incubation and testing of new venture ideas. Such a strategy leads to the establishment of a micro-ecosystem of aspiring entrepreneurs and others in a business laboratory environment. The goal is to create a mini…

Curley, Martin G.; Formica, Piero

2010-01-01

388

Plasma wake field accelerator  

SciTech Connect

A new scheme of electron acceleration, employing relativistic electron bunches in a cold plasma, is analyzed. The wake field of a leading bunch is derived in a single-particle model. We then extend the model to include finite bunch length effect. In particular, we discuss the relation between the charge distributions of the driving bunch and the energies transformable to the trailing electrons. It is shown that for symmetric charge distribution of the driving bunches, the maximum energy gain for a driven electron is 2..gamma../sub 0/mc/sup 2/. This limitation can be overcome by introducing asymmetric charge distributions. 13 refs., 5 figs.

Chen, P.; Dawson, J.M.

1985-03-01

389

Accelerated Innovation Pilot  

NASA Technical Reports Server (NTRS)

Opportunities: I. Engage NASA team (examples) a) Research and technology calls . provide suggestions to AES, HRP, OCT. b) Use NASA@Work to solicit other ideas; (possibly before R+D calls). II. Stimulate collaboration (examples) a) NHHPC. b) Wharton Mack Center for Technological Innovation (Feb 2013). c) International ] DLR ] :envihab (July 2013). d) Accelerated research models . NSF, Myelin Repair Foundation. III. Engage public Prizes (open platform: InnoCentive, yet2.com, NTL; Rice Business Plan, etc.) IV. Use same methods to engage STEM.

Davis, Jeffrey

2012-01-01

390

Laser plasma accelerators  

SciTech Connect

This review article highlights the tremendous evolution of the research on laser plasma accelerators which has, in record time, led to the production of high quality electron beams at the GeV level, using compact laser systems. I will describe the path we followed to explore different injection schemes and I will present the most significant breakthrough which allowed us to generate stable, high peak current and high quality electron beams, with control of the charge, of the relative energy spread and of the electron energy.

Malka, V. [Laboratoire d'Optique Appliquee, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

2012-05-15

391

Accelerating Commercial Remote Sensing  

NASA Technical Reports Server (NTRS)

Through the Visiting Investigator Program (VIP) at Stennis Space Center, Community Coffee was able to use satellites to forecast coffee crops in Guatemala. Using satellite imagery, the company can produce detailed maps that separate coffee cropland from wild vegetation and show information on the health of specific crops. The data can control coffee prices and eventually may be used to optimize application of fertilizers, pesticides and irrigation. This would result in maximal crop yields, minimal pollution and lower production costs. VIP is a mechanism involving NASA funding designed to accelerate the growth of commercial remote sensing by promoting general awareness and basic training in the technology.

1995-01-01

392

Status and perspectives for the INFN Frascati National Laboratory  

NASA Astrophysics Data System (ADS)

In the recent years a great effort has been done by the accelerator division in terms of research and development of new techniques of acceleration, new proposals on possible future accelerator related activities (IRIDE) and studies to improve the luminosity of the existing collider (DA?NE). In parallel, the KLOE experiment has upgraded the detector installing an inner tracker to improve its reconstruction power in the vicinity of the vertex and a calorimeter system to improve its ability to distinguish kaon decays. In this paper I'll briefly summarize some of the most relevant activities taking place at the INFN Frascati National Laboratory and their possible future perspectives.

Branchini, P.

2014-06-01

393

Particle Acceleration by MHD Turbulence  

E-print Network

Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for revisions in the picture of particle acceleration. We make use of the recently established scaling of slow and fast MHD modes in strong and weak MHD turbulence to provide a systematic study of particle acceleration in magnetic pressure (low-$\\beta$) and gaseous pressure (high-$\\beta$) dominated plasmas. We consider the acceleration by large scale compressions in both slow and fast particle diffusion limits. We compare the results with the acceleration rate that arises from resonance scattering and Transit-Time Damping (TTD). We establish that fast modes accelerate particles more efficiently than slow modes. We find that particle acceleration by pitch-angle scattering and TTD dominates acceleration by slow or fast modes when the spatial diffusion rate is small. When the rate of spatial diffusion of particles is high, we establish an enhancement of the efficiency of particle acceleration by slow and fast modes in weak turbulence. We show that highly supersonic turbulence is an efficient agent for particle acceleration. We find that even incompressible turbulence can accelerate particles on the scales comparable with the particle mean free path.

Jungyeon Cho; A. Lazarian

2005-10-21

394

THE 13TH ADVANCED ACCELERATOR CONCEPTS WORKSHOP (AAC'8)  

SciTech Connect

The Thirteenth Workshop on Advanced Accelerator Concepts (AAC) was held from July 27 to August 2, 2008 at the Chaminade Conference Center in Santa Cruz, California, USA, organized by the Lawrence Berkeley National Laboratory and the University of California at Berkeley. There were unprecedented levels of interest in the 2008 AAC Workshop, and participation was by invitation, with 215 workshop attendees, including 58 students. Reflecting the world-wide growth of the advanced accelerator community, there was significant international participation, with participants from twelve countries attending.

Leemans, Wim [UC Berkeley] [UC Berkeley; Schroder, Carl B.; Esarey, Eric

2008-07-15

395

Low energy demonstration accelerator technical area 53  

SciTech Connect

As part of the Department of Energy`s (DOE) need to maintain the capability of producing tritium in support of its historic and near-term stewardship of the nation`s nuclear weapons stockpile, the agency has recently completed a Programmatic Environmental Impact Statement for Tritium Supply and Recycling. The resulting Record of Decision (ROD) determined that over the next three years the DOE would follow a dual-track acquisition strategy that assures tritium production for the nuclear weapon stockpile in a rapid, cost effective, and safe manner. Under this strategy the DOE will further investigate and compare two options for producing tritium: (1) purchase of an existing commercial light-water reactor or irradiation services with an option to purchase the reactor for conversion to a defense facility; and (2) design, build, and test critical components of a system for accelerator production of tritium (APT). The final decision to select the primary production option will be made by the Secretary of Energy in the October 1998 time frame. The alternative not chosen as the primary production method, if feasible, would be developed as a back-up tritium supply source. This Environmental Assessment (EA) analyzes the potential environmental effects that would be expected to occur if the DOE were to design, build, and test critical prototypical components of the accelerator system for tritium production, specifically the front-end low-energy section of the accelerator, at Los Alamos National Laboratory. The Low Energy Demonstration Accelerator (LEDA) would be incrementally developed and tested in five separate stages over the next seven years. The following issues were evaluated for the proposed action: utility demands, air, human health, environmental restoration, waste management, transportation, water, threatened and endangered species, wetlands, cultural resources, and environmental justice.

NONE

1996-04-01

396

Development of a residual acceleration data reduction and dissemination plan  

NASA Technical Reports Server (NTRS)

A major obstacle in evaluating the residual acceleration environment in an orbiting space laboratory is the amount of data collected during a given mission: gigabytes of data will be available as SAMS units begin to fly regularly. Investigators taking advantage of the reduced gravity conditions of space should not be overwhelmed by the accelerometer data which describe these conditions. We are therefore developing a data reduction and analysis plan that will allow principal investigators of low-g experiments to create experiment-specific residual acceleration data bases for post-flight analysis. The basic aspects of the plan can also be used to characterize the acceleration environment of earth orbiting laboratories. Our development of the reduction plan is based on the following program of research: the identification of experiment sensitivities by order of magnitude estimates and numerical modelling; evaluation of various signal processing techniques appropriate for the reduction, supplementation, and dissemination of residual acceleration data; and testing and implementation of the plan on existing acceleration data bases. The orientation of the residual acceleration vector with respect to some set of coordinate axes is important for experiments with known directional sensitivity. Orientation information can be obtained from the evaluation of direction cosines. Fourier analysis is commonly used to transform time history data into the frequency domain. Common spectral representations are the amplitude spectrum which gives the average of the components of the time series at each frequency and the power spectral density which indicates the power or energy present in the series per unit frequency interval. The data reduction and analysis scheme developed involves a two tiered structure to: (1) identify experiment characteristics and mission events that can be used to limit the amount of accelerator data an investigator should be interested in; and (2) process the data in a way that will be meaningful to the experiment objectives. A general outline of the plan is given.

Rogers, Melissa J. B.

1992-01-01

397

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

SciTech Connect

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

Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas Jr. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742-3511 (United States)

2010-11-04

398

Early History of Jefferson Laboratory  

NASA Astrophysics Data System (ADS)

This talk will focus on the history of Jefferson Laboratory from its inception as the NEAL proposal by the Southeastern Universities Research Association (SURA) in 1980, to about 1986 -- two years after the arrival of Hermann Grunder and his Berkeley team. Major themes are (i) a national decision to build a high energy, high duty factor electron accelerator for basic nuclear physics research, (ii) open competition established by the DOE, (iii) formation of SURA, and (iv) interest of SURA physicists (particularly at UVA and W&M) in this research. I will discuss the scientific, technical, and political issues that eventually lead to the selection of the SURA proposal, the choice of Newport News as the site, and the decision to adopt a recirculating superconducting ring for the final design.

Gross, Franz

2011-10-01

399

Accelerated partial breast irradiation.  

PubMed

Local therapies to treat newly diagnosed breast cancer include a lumpectomy with radiation therapy or a mastectomy. The 20-year data from studies about the safety and efficacy of lumpectomy with full-breast radiation therapy support the safety of this regimen and its role to decrease the risk of ipsilateral recurrence and increase long-term survivorship of women with breast cancer. Accelerated partial breast irradiation (APBI) provides radiation therapy to the tumor bed but spares the remaining breast tissue. APBI accelerates the time required to complete the therapy regimen, with a range of one intraoperative session to five consecutive days compared to five to seven weeks. Several techniques exist to administer APBI, including the insertion of a balloon into the lumpectomy space. Of interest is the widespread use of APBI in community and academic settings that has preceded outcomes of large, randomized clinical trials. Because of selection bias in a number of small, single-institution, nonrandomized studies, published data are of limited value to ensure APBI as a standard of care. PMID:25253109

Bauer, Elfrida; Lester, Joanne L

2014-10-01

400

Optical Bragg accelerators  

NASA Astrophysics Data System (ADS)

It is demonstrated that a Bragg waveguide consisting of a series of dielectric layers may form an excellent optical acceleration structure. Confinement of the accelerating fields is achieved, for both planar and cylindrical configurations by adjusting the first dielectric layer width. A typical structure made of silica and zirconia may support gradients of the order of 1GV/m with an interaction impedance of a few hundreds of ohms and with an energy velocity of less than 0.5c . An interaction impedance of about 1000? may be obtained by replacing the Zirconia with a (fictitious) material of ?=25 . Special attention is paid to the wake field developing in such a structure. In the case of a relatively small number of layers, it is shown that the total electromagnetic power emitted is proportional to the square of the number of electrons in the macrobunch and inversely proportional to the number of microbunches; this power is also inversely proportional to the square of the internal radius of the structure for a cylindrical structure, and to the width of the vacuum core in a planar structure. Quantitative results are given for a higher number of dielectric layers, showing that in comparison to a structure bounded by metallic walls, the emitted power is significantly smaller due to propagation bands allowing electromagnetic energy to escape.

Mizrahi, Amit; Schächter, Levi

2004-07-01

401

Broadband accelerator control network  

SciTech Connect

A broadband data communications network has been implemented at BNL for control of the Alternating Gradient Synchrotron (AG) proton accelerator, using commercial CATV hardware, dual coaxial cables as the communications medium, and spanning 2.0 km. A 4 MHz bandwidth Digital Control channel using CSMA-CA protocol is provided for digital data transmission, with 8 access nodes available over the length of the RELWAY. Each node consists of an rf modem and a microprocessor-based store-and-forward message handler which interfaces the RELWAY to a branch line implemented in GPIB. A gateway to the RELWAY control channel for the (preexisting) AGS Computerized Accelerator Operating system has been constructed using an LSI-11/23 microprocessor as a device in a GPIB branch line. A multilayer communications protocol has been defined for the Digital Control Channel, based on the ISO Open Systems Interconnect layered model, and a RELWAY Device Language defined as the required universal language for device control on this channel.

Skelly, J.; Clifford, T.; Frankel, R.

1983-01-01

402

List of Registrants Last Updated 12/17/2009  

E-print Network

sedyson@cps.k12.il.usChicago Public Schools40. Samuel Dyson eichten@fnal.govFermi National Accelerator@fnal.govFermilab / University of Sao Paulo2. Ivone Albuquerque ankenbra@fnal.govMuons, Inc.3. Chuck Ankenbrandt appel@illinois.eduUniversity of Illinois14. Chris Bouchard adbrandt@illinois.eduIntelligent Devices, Inc15. Robert Brandt broemmel

Quigg, Chris

403

Particle acceleration in pulsar magnetospheres  

NASA Technical Reports Server (NTRS)

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

Baker, K. B.

1978-01-01

404

Magnetic Insulation for Electrostatic Accelerators  

SciTech Connect

The voltage gradient which can be sustained between electrodes without electrical breakdowns is usually one of the most important parameters in determining the performance which can be obtained in an electrostatic accelerator. We have recently proposed a technique which might permit reliable operation of electrostatic accelerators at higher electric field gradients, perhaps also with less time required for the conditioning process in such accelerators. The idea is to run an electric current through each accelerator stage so as to produce a magnetic field which envelopes each electrode and its electrically conducting support structures. Having the magnetic field everywhere parallel to the conducting surfaces in the accelerator should impede the emission of electrons, and inhibit their ability to acquire energy from the electric field, thus reducing the chance that local electron emission will initiate an arc. A relatively simple experiment to assess this technique is being planned. If successful, this technique might eventually find applicability in electrostatic accelerators for fusion and other applications.

Grisham, L. R. [Princeton Plasma Physics Laboratory, P. O. Box 451, Princeton, New Jersey 08543 (United States)

2011-09-26

405

Accelerator Technology for the Mankind  

E-print Network

Particle accelerators technology is one of the generic technologies which is locomotive of the development in almost all fields of science and technology. According to the U.S. Department of Energy: "Accelerators underpin every activity of the Office of Science and, increasingly, of the entire scientific enterprise. From biology to medicine, from materials to metallurgy, from elementary particles to the cosmos, accelerators provide the microscopic information that forms the basis for scientific understanding and applications. The combination of ground and satellite based observatories and particle accelerators will advance our understanding of our world, our galaxy, our universe, and ourselves." Because of this, accelerator technology should become widespread all over the world. Existing situation shows that a large portion of the world, namely the South and Mid-East, is poor on the accelerator technology. UNESCO has recognized this deficit and started SESAME project in Mid-East, namely Jordan. Turkic Acceler...

Sultansoy, S

2006-01-01

406

Laser acceleration and its future  

PubMed Central

Laser acceleration is based on the concept to marshal collective fields that may be induced by laser. In order to exceed the material breakdown field by a large factor, we employ the broken-down matter of plasma. While the generated wakefields resemble with the fields in conventional accelerators in their structure (at least qualitatively), it is their extreme accelerating fields that distinguish the laser wakefield from others, amounting to tiny emittance and compact accelerator. The current research largely falls on how to master the control of acceleration process in spatial and temporal scales several orders of magnitude smaller than the conventional method. The efforts over the last several years have come to a fruition of generating good beam properties with GeV energies on a table top, leading to many applications, such as ultrafast radiolysis, intraoperative radiation therapy, injection to X-ray free electron laser, and a candidate for future high energy accelerators. PMID:20228616

Tajima, Toshiki

2010-01-01

407

Nb3Sn accelerator magnet development around the world  

SciTech Connect

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

Michael J. Lamm

2003-06-23

408

Kr II laser-induced fluorescence for measuring plasma acceleration.  

PubMed

We present the application of laser-induced fluorescence of singly ionized krypton as a diagnostic technique for quantifying the electrostatic acceleration within the discharge of a laboratory cross-field plasma accelerator also known as a Hall effect thruster, which has heritage as spacecraft propulsion. The 728.98 nm Kr II transition from the metastable 5d(4)D(7/2) to the 5p(4)P(5/2)(?) state was used for the measurement of laser-induced fluorescence within the plasma discharge. From these measurements, it is possible to measure velocity as krypton ions are accelerated from near rest to approximately 21 km/s (190 eV). Ion temperature and the ion velocity distributions may also be extracted from the fluorescence data since available hyperfine splitting data allow for the Kr II 5d(4)D(7/2)-5p(4)P(5/2)(?) transition lineshape to be modeled. From the analysis, the fluorescence lineshape appears to be a reasonable estimate for the relatively broad ion velocity distributions. However, due to an apparent overlap of the ion creation and acceleration regions within the discharge, the distributed velocity distributions increase ion temperature determination uncertainty significantly. Using the most probable ion velocity as a representative, or characteristic, measure of the ion acceleration, overall propellant energy deposition, and effective electric fields may be calculated. With this diagnostic technique, it is possible to nonintrusively characterize the ion acceleration both within the discharge and in the plume. PMID:23126755

Hargus, W A; Azarnia, G M; Nakles, M R

2012-10-01

409

Empirical evidence for acceleration-dependent amplification factors  

USGS Publications Warehouse

Site-specific amplification factors, Fa and Fv, used in current U.S. building codes decrease with increasing base acceleration level as implied by the Loma Prieta earthquake at 0.1g and extrapolated using numerical models and laboratory results. The Northridge earthquake recordings of 17 January 1994 and subsequent geotechnical data permit empirical estimates of amplification at base acceleration levels up to 0.5g. Distance measures and normalization procedures used to infer amplification ratios from soil-rock pairs in predetermined azimuth-distance bins significantly influence the dependence of amplification estimates on base acceleration. Factors inferred using a hypocentral distance norm do not show a statistically significant dependence on base acceleration. Factors inferred using norms implied by the attenuation functions of Abrahamson and Silva show a statistically significant decrease with increasing base acceleration. The decrease is statistically more significant for stiff clay and sandy soil (site class D) sites than for stiffer sites underlain by gravely soils and soft rock (site class C). The decrease in amplification with increasing base acceleration is more pronounced for the short-period amplification factor, Fa, than for the midperiod factor, Fv.

Borcherdt, R.D.

2002-01-01

410

Real-time observation of laser-driven electron acceleration  

NASA Astrophysics Data System (ADS)

Electron acceleration by laser-driven plasma waves is capableof producing ultra-relativistic, quasi-monoenergetic electron bunches with orders of magnitude higher accelerating gradients and much shorter electron pulses than state-of-the-art radio-frequency accelerators. Recent developments have shown peak energies reaching into the GeV range and improved stability and control over the energy spectrum and charge. Future applications, such as the development of laboratory X-ray sources with unprecedented peak brilliance or ultrafast time-resolved measurements critically rely on a temporal characterization of the acceleration process and the electron bunch. Here, we report the first real-time observation of the accelerated electron pulse and the accelerating plasma wave. Our time-resolved study allows a single-shot measurement of the 5.8-2.1+1.9 fs electron bunch full-width at half-maximum (2.5-0.9+0.8 fs root mean square) as well as the plasma wave with a density-dependent period of 12-22fs and reveals the evolution of the bunch, its position in the surrounding plasma wave and the wake dynamics. The results afford promise for brilliant, sub-ångström-wavelength ultrafast electron and photon sources for diffraction imaging with atomic resolution in space and time.

Buck, Alexander; Nicolai, Maria; Schmid, Karl; Sears, Chris M. S.; Sävert, Alexander; Mikhailova, Julia M.; Krausz, Ferenc; Kaluza, Malte C.; Veisz, Laszlo

2011-07-01

411

The BNL Accelerator Test Facility and experimental program  

SciTech Connect

The Accelerator Test Facility (ATF) at BNL is a users` facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF`s experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

Ben-Zvi, I. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics

1992-09-01

412

The LILIA (laser induced light ions acceleration) experiment at LNF  

NASA Astrophysics Data System (ADS)

Laser-matter interaction at relativistic intensities opens up new research fields in the particle acceleration and related secondary sources, with immediate applications in medical diagnostics, biophysics, material science, inertial confinement fusion, up to laboratory astrophysics. In particular laser-driven ion acceleration is very promising for hadron therapy once the ion energy will attain a few hundred MeV. The limited value of the energy up to now obtained for the accelerated ions is the drawback of such innovative technique to the real applications. LILIA (laser induced light ions acceleration) is an experiment now running at LNF (Frascati) with the goal of producing a real proton beam able to be driven for significant distances (50-75 cm) away from the interaction point and which will act as a source for further accelerating structure. In this paper the description of the experimental setup, the preliminary results of solid target irradiation and start to end simulation for a post-accelerated beam up to 60 MeV are given.

Agosteo, S.; Anania, M. P.; Caresana, M.; Cirrone, G. A. P.; De Martinis, C.; Delle Side, D.; Fazzi, A.; Gatti, G.; Giove, D.; Giulietti, D.; Gizzi, L. A.; Labate, L.; Londrillo, P.; Maggiore, M.; Nassisi, V.; Sinigardi, S.; Tramontana, A.; Schillaci, F.; Scuderi, V.; Turchetti, G.; Varoli, V.; Velardi, L.

2014-07-01

413

Solar particle acceleration and propagation  

NASA Technical Reports Server (NTRS)

The research performed in the period 1983-1986 on solar-particle acceleration and propagation is discussed. Special attention is given to satellite-based observations of large solar energetic particles and (He-3)-rich events; measurements of solar gamma rays, neutrons, and low-energy (1-100-keV) electrons; and observations related to the interplanetary propagation of fast particles. Consideration is also given to theoretical acceleration models based on satellite measurements of accelerated ions.

Lin, R. P.

1987-01-01

414

Accelerating and Retarding Anomalous Diffusion  

E-print Network

In this paper Gaussian models of retarded and accelerated anomalous diffusion are considered. Stochastic differential equations of fractional order driven by single or multiple fractional Gaussian noise terms are introduced to describe retarding and accelerating subdiffusion and superdiffusion. Short and long time asymptotic limits of the mean squared displacement of the stochastic processes associated with the solutions of these equations are studied. Specific cases of these equations are shown to provide possible descriptions of retarding or accelerating anomalous diffusion.

Chai Hok Eab; S. C. Lim

2012-01-27

415

EM Structures and Laser Acceleration  

NASA Astrophysics Data System (ADS)

Several dielectric optical acceleration structures that have been designed in recent years are being compared. The unique properties of these structures entail challenging design of an overall acceleration module. Four possible configurations are being analyzed. Two important concepts are discussed: train of micro-bunches and feedback loop. While the former facilitates acceleration of a large number of electrons, the latter enables energy recovery leading to higher efficiency. Their implications are considered and some rough estimates of luminosity are considered.

Schächter, Levi

2004-12-01

416

Coherent Acceleration of Material Wavepackets  

E-print Network

We study the quantum dynamics of a material wavepacket bouncing off a modulated atomic mirror in the presence of a gravitational field. We find the occurrence of coherent accelerated dynamics for atoms. The acceleration takes place for certain initial phase space data and within specific windows of modulation strengths. The realization of the proposed acceleration scheme is within the range of present day experimental possibilities.

Farhan Saif; Pierre Meystre

2006-08-16

417

Coherent multimoded dielectric wakefield accelerators.  

SciTech Connect

There has recently been a study of the potential uses of multimode dielectric structures for wakefield acceleration [1]. This technique is based on adjusting the wakefield modes of the structure to constructively interfere at certain delays with respect to the drive bunch, thus providing an accelerating gradient enhancement over single mode devices. In this report we examine and attempt to clarify the issues raised by this work in the light of the present state of the art in wakefield acceleration.

Power, J.

1998-07-16

418

Comparison of a 250 kV single-stage accelerator mass spectrometer with a 5 MV tandem accelerator mass spectrometer--fitness for purpose in bioanalysis.  

PubMed

The introduction of 'compact' accelerator mass spectrometers into biomedical science, including use in drug metabolism and bioanalytical applications, is an exciting recent development. Comparisons are presented here between a more established and relatively large tandem accelerator which operates at up to 5 MV and a conventional laboratory-sized 250 kV single-stage accelerator mass spectrometer. Biological samples were enriched with low levels of radiocarbon, then converted into graphite prior to analysis on each of the two instruments. The data obtained showed the single-stage instrument to be capable of delivering comparable results, and thus able to provide similar study support, with that provided by the 5 MV instrument, without the significant overheads and complexities which are inherent to the operation of the larger instrument. We believe that the advent of these laboratory-sized accelerator mass spectrometry (AMS) instruments represents a real turning point in the potential for application of AMS by a wider user group. PMID:19009519

Young, G C; Corless, S; Felgate, C C; Colthup, P V

2008-12-01

419

ACCELERATE YOUR FUTURE Israel Careers  

E-print Network

ACCELERATE YOUR FUTURE Israel Careers INNOVATE COLLABORATE EXECUTE Job Description Definition and innovative, · Capable of seeing the big picture and bring various approaches and parameters to problem

Rimon, Elon

420

High field gradient particle accelerator  

DOEpatents

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

Nation, J.A.; Greenwald, S.

1989-05-30

421

High field gradient particle accelerator  

DOEpatents

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

1989-01-01

422

A Summary of the Quasi-Steady Acceleration Environment on-Board STS-94 (MSL-1)  

NASA Technical Reports Server (NTRS)

The continuous free-fall state of a low Earth orbit experienced by NASA's Orbiters results in a unique reduced gravity environment. While microgravity science experiments are conducted in this reduced gravity environment, various accelerometer systems measure and record the microgravity acceleration environment for real-time and post-flight correlation with microgravity science data. This overall microgravity acceleration environment is comprised of quasi-steady, oscillatory, and transient contributions. The First Microgravity Science Laboratory (MSL-1) payload was dedicated to experiments studying various microgravity science disciplines, including combustion, fluid physics, and materials processing. In support of the MSL-1 payload, two systems capable of measuring the quasi-steady acceleration environment were flown: the Orbital Acceleration Research Experiment (OARE) and the Microgravity Measurement Assembly (MMA) system's Accelerometre Spatiale Triaxiale most evident in the quasi-steady acceleration regime. Utilizing such quasi-steady events, a comparison and summary of the quasi-steady acceleration environment for STS-94 will be presented

McPherson, Kevin M.; Nati, Maurizio; Touboul, Pierre; Schuette, Andreas; Sablon, Gert

1999-01-01

423

Network acceleration techniques  

NASA Technical Reports Server (NTRS)

Splintered offloading techniques with receive batch processing are described for network acceleration. Such techniques offload specific functionality to a NIC while maintaining the bulk of the protocol processing in the host operating system ("OS"). The resulting protocol implementation allows the application to bypass the protocol processing of the received data. Such can be accomplished this by moving data from the NIC directly to the application through direct memory access ("DMA") and batch processing the receive headers in the host OS when the host OS is interrupted to perform other work. Batch processing receive headers allows the data path to be separated from the control path. Unlike operating system bypass, however, the operating system still fully manages the network resource and has relevant feedback about traffic and flows. Embodiments of the present disclosure can therefore address the challenges of networks with extreme bandwidth delay products (BWDP).

Crowley, Patricia (Inventor); Awrach, James Michael (Inventor); Maccabe, Arthur Barney (Inventor)

2012-01-01

424

Accelerating Spectrum Sharing Technologies  

SciTech Connect

Spectrum sharing potentially holds the promise of solving the emerging spectrum crisis. However, technology innovators face the conundrum of developing spectrum sharing technologies without the ability to experiment and test with real incumbent systems. Interference with operational incumbents can prevent critical services, and the cost of deploying and operating an incumbent system can be prohibitive. Thus, the lack of incumbent systems and frequency authorization for technology incubation and demonstration has stymied spectrum sharing research. To this end, industry, academia, and regulators all require a test facility for validating hypotheses and demonstrating functionality without affecting operational incumbent systems. This article proposes a four-phase program supported by our spectrum accountability architecture. We propose that our comprehensive experimentation and testing approach for technology incubation and demonstration will accelerate the development of spectrum sharing technologies.

Juan D. Deaton; Lynda L. Brighton; Rangam Subramanian; Hussein Moradi; Jose Loera

2013-09-01

425

MRI temporal acceleration techniques.  

PubMed

In recent years, there has been an explosive growth of magnetic resonance imaging (MRI) techniques that allow faster scan speed by exploiting temporal or spatiotemporal redundancy of the images. These techniques improve the performance of dynamic imaging significantly across multiple clinical applications, including cardiac functional examinations, perfusion imaging, blood flow assessment, contrast-enhanced angiography, functional MRI, and interventional imaging, among others. The scan acceleration permits higher spatial resolution, increased temporal resolution, shorter scan duration, or a combination of these benefits. Along with the exciting developments is a dizzying proliferation of acronyms and variations of the techniques. The present review attempts to summarize this rapidly growing topic and presents conceptual frameworks to understand these techniques in terms of their underlying mechanics and connections. Techniques from view sharing, keyhole, k-t, to compressed sensing are covered. PMID:22903655

Tsao, Jeffrey; Kozerke, Sebastian

2012-09-01

426

Paraelectric gas flow accelerator  

NASA Technical Reports Server (NTRS)

A substrate is configured with first and second sets of electrodes, where the second set of electrodes is positioned asymmetrically between the first set of electrodes. When a RF voltage is applied to the electrodes sufficient to generate a discharge plasma (e.g., a one-atmosphere uniform glow discharge plasma) in the gas adjacent to the substrate, the asymmetry in the electrode configuration results in force being applied to the active species in the plasma and in turn to the neutral background gas. Depending on the relative orientation of the electrodes to the gas, the present invention can be used to accelerate or decelerate the gas. The present invention has many potential applications, including increasing or decreasing aerodynamic drag or turbulence, and controlling the flow of active and/or neutral species for such uses as flow separation, altering heat flow, plasma cleaning, sterilization, deposition, etching, or alteration in wettability, printability, and/or adhesion.

Sherman, Daniel M. (Inventor); Wilkinson, Stephen P. (Inventor); Roth, J. Reece (Inventor)

2001-01-01

427

Pulsed Plasma Accelerator Modeling  

NASA Technical Reports Server (NTRS)

This report presents the main results of the modeling task of the PPA project. The objective of this task is to make major progress towards developing a new computational tool with new capabilities for simulating cylindrically symmetric 2.5 dimensional (2.5 D) PPA's. This tool may be used for designing, optimizing, and understanding the operation of PPA s and other pulsed power devices. The foundation for this task is the 2-D, cylindrically symmetric, magnetohydrodynamic (MHD) code PCAPPS (Princeton Code for Advanced Plasma Propulsion Simulation). PCAPPS was originally developed by Sankaran (2001, 2005) to model Lithium Lorentz Force Accelerators (LLFA's), which are electrode based devices, and are typically operated in continuous magnetic field to the model, and implementing a first principles, self-consistent algorithm to couple the plasma and power circuit that drives the plasma dynamics.

Goodman, M.; Kazeminezhad, F.; Owens, T.

2009-01-01

428

Pulsed electromagnetic acceleration  

NASA Technical Reports Server (NTRS)

Direct measurements of the power deposited in the anode of a multimegawatt MPD accelerator using thermocouples attached to a thin shell anode reveal a dramatic decrease in the fractional anode power from 50% at 200 KW input power to less than 10% at 20 MW power. The corresponding local power flux peak at a value of 10,000 W/sq cm at the lip of the anode exhaust orifice, a distribution traced to a corresponding peak in the local current density at the anode. A comparison of voltage-current characteristics and spectral photographs of the MPD discharge using quartz, boron nitride and plexiglas insulators with various mass injection configurations led to the identification of different voltage modes and regions of ablation free operation. The technique of piezoelectric impact pressure measurement in the MPD exhaust flow was refined to account for the effects due to probe yaw angle.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1973-01-01

429

Accelerator mass spectrometry  

SciTech Connect

Accelerator mass spectroscopy (AMS) can be used for efficient detection of long-lived isotopes at part-per-quadrillion sensitivities with good precision. In this article we present an overview of AMS and its recent use in archaeology, geochemistry and biomolecular tracing. All AMS systems use cesium sputter ion sources to produce negative ions from a small button of a solid sample containing the element of interest, such as graphite, metal halide, or metal oxide, often mixed with a metal powder as binder and thermal conductor. Experience shows that both natural and biomedical samples are compatible in a single AMS system, but few other AMS sites make routine {sup 14}C measurements for both dating and tracing. AMS is, in one sense, just `a very sensitive decay counter`, but if AMS sensitivity is creatively coupled to analytical chemistry of certain isotopes, whole new areas of geosciences, archaeology, and life sciences can be explored. 29 refs., 2 figs., 1 tab.

Vogel, J.S.; Turteltaub, K.W.; Finkel, R. [Lawrence Livermore National Lab., CA (United States); Nelson, D.E.

1995-06-01

430

Argonne's Laboratory computing center - 2007 annual report.  

SciTech Connect

Argonne National Laboratory founded the Laboratory Computing Resource Center (LCRC) in the spring of 2002 to help meet pressing program needs for computational modeling, simulation, and analysis. The guiding mission is to provide critical computing resources that accelerate the development of high-performance computing expertise, applications, and computations to meet the Laboratory's challenging science and engineering missions. In September 2002 the LCRC deployed a 350-node computing cluster from Linux NetworX to address Laboratory needs for mid-range supercomputing. This cluster, named 'Jazz', achieved over a teraflop of computing power (1012 floating-point calculations per second) on standard tests, making it the Laboratory's first terascale computing system and one of the 50 fastest computers in the world at the time. Jazz was made available to early users in November 2002 while the system was undergoing development and configuration. In April 2003, Jazz was officially made available for production operation. Since then, the Jazz user community has grown steadily. By the end of fiscal year 2007, there were over 60 active projects representing a wide cross-section of Laboratory expertise, including work in biosciences, chemistry, climate, computer science, engineering applications, environmental science, geoscience, information science, materials science, mathematics, nanoscience, nuclear engineering, and physics. Most important, many projects have achieved results that would have been unobtainable without such a computing resource. The LCRC continues to foster growth in the computational science and engineering capability and quality at the Laboratory. Specific goals include expansion of the use of Jazz to new disciplines and Laboratory initiatives, teaming with Laboratory infrastructure providers to offer more scientific data management capabilities, expanding Argonne staff use of national computing facilities, and improving the scientific reach and performance of Argonne's computational applications. Furthermore, recognizing that Jazz is fully subscribed, with considerable unmet demand, the LCRC has framed a 'path forward' for additional computing resources.

Bair, R.; Pieper, G. W.

2008-05-28

431

The Microscale Laboratory.  

ERIC Educational Resources Information Center

The materials needed and the procedures used in three microscale chemical laboratory experiments are detailed. Included are a microscale organic synthesis, a two-step synthetic sequence for the microscale organic laboratory, and a small-scale equilibrium experiment. (CW)

Zipp, Arden P.

1990-01-01

432

Biotechnology Laboratory Spring 2012  

E-print Network

CH369T Biotechnology Laboratory Spring 2012 Instructor: Dr. Gene McDonald Office: WEL 3.270C Phone, and at the same time to introduce you to issues associated with various biotechnology laboratory operations. After

433

NDCX-II, A New Induction Linear Accelerator for Warm Dense Matter Research  

SciTech Connect

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

Leitner, M.; Bieniosek, F.; Kwan, J.; Logan, G.; Waldron, W.; Barnard, J.J.; Friedman, A.; Sharp, B.; Gilson, E.; Davidson, R.

2009-06-01

434

EPA Environmental Chemistry Laboratory  

NASA Technical Reports Server (NTRS)

The Environmental Protection Agency's (EPA) Chemistry Laboratory (ECL) is a national program laboratory specializing in residue chemistry analysis under the jurisdiction of the EPA's Office of Pesticide Programs in Washington, D.C. At Stennis Space Center, the laboratory's work supports many federal anti-pollution laws. The laboratory analyzes environmental and human samples to determine the presence and amount of agricultural chemicals and related substances. Pictured, ECL chemists analyze environmental and human samples for the presence of pesticides and other pollutants.

1993-01-01

435

Current and future uses of accelerators in particle astrophysics  

NASA Technical Reports Server (NTRS)

Beams of artificially accelerated heavy ions, protons, antiprotons, electrons, and positrons currently available at (and planned for) numerous facilities around the world are a valuable resource to the Cosmic Ray community. Such beams have been used to test detector concepts, calibrate balloon-borne and space flight experiments and to measure fundamental nuclear physics parameter necessary for the interpretation of Cosmic Ray data. As new experiments are flown the quality and extent of Cosmic Ray measurements will continue to improve. It will be necessary to increase activity at ground based accelerators in order to test/calibrate these new instruments and to maintain (or possibly improve) the ability to interpret these data. In this area, the newly formed Transport Collaboration, supported by NASA, will be providing new nuclear interaction cross section measurements for beams with Z less than or = 58 and supporting new instrument calibrations at the Lawrence Berkeley Laboratory Bevalac accelerator.

Guzik, T. G.

1990-01-01

436

Transformer ratio improvement for beam based plasma accelerators  

NASA Astrophysics Data System (ADS)

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R ? 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl

2012-12-01

437

Transformer ratio improvement for beam based plasma accelerators  

SciTech Connect

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R {<=} 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl [University of California, Los Angeles, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); University of Southern California, Department of Electrical Engineering, Los Angeles, CA 90089 U.S.A. and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Accelerator Test Facility, Brookhaven National Lab, Upton, NY, 11973 (United States)

2012-12-21

438

Accelerator technology program. Status report, July-December 1982  

SciTech Connect

Major projects of the Los Alamos National Laboratory's Accelerator Technology Division are discussed, covering activities that occurred during the last six months of calendar 1982. The first sections report highlights in beam dynamics, accelerator inertial fusion, radio-frequency structure development, the racetrack microtron, CERN high-energy physics experiment NA-12, and high-flux radiographic linac study. Next we report on selected proton Storage Ring activities that have made significant progress during this reporting period, followed by an update on the free electron laser. The Fusion Materials Irradiation Test Facility work is discussed next, then progress on the klystron development project and on the gyrocon project. The activities of the newly formed Theory and Simulation Group are outlined. The last section covers activities concerning the accelerator test stand for the neutral particle beam program.

Jameson, R.A. (comp.)

1984-05-01

439

COAXIAL TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR  

SciTech Connect

Theory, computations, and experimental apparatus are presented that describe and are intended to confirm novel properties of a coaxial two-channel dielectric wake field accelerator. In this configuration, an annular drive beam in the outer coaxial channel excites multimode wakefields which, in the inner channel, can accelerate a test beam to an energy much higher than the energy of the drive beam. This high transformer ratio is the result of judicious choice of the dielectric structure parameters, and of the phase separation between drive bunches and test bunches. A structure with cm-scale wakefields has been build for tests at the Argonne Wakefield Accelerator Laboratory, and a structure with mm-scale wakefields has been built for tests at the SLAC FACET facility. Both tests await scheduling by the respective facilities.

Hirshfield, Jay L. [Omega-P, Inc.

2013-04-30

440

Effects of Spatial Gradients on Electron Runaway Acceleration  

NASA Technical Reports Server (NTRS)

The runaway process is known to accelerate electrons in many laboratory plasmas and has been suggested as an acceleration mechanism in some astrophysical plasmas, including solar flares. Current calculations of the electron velocity distributions resulting from the runaway process are greatly restricted because they impose spatial homogeneity on the distribution. We have computed runaway distributions which include consistent development of spatial gradients in the energetic tail. Our solution for the electron velocity distribution is presented as a function of distance along a finite length acceleration region, and is compared with the equivalent distribution for the infinitely long homogenous system (i.e., no spatial gradients), as considered in the existing literature. All these results are for the weak field regime. We also discuss the severe restrictiveness of this weak field assumption.

MacNeice, Peter; Ljepojevic, N. N.

1996-01-01

441

Neutron Transport Methods for Accelerator-Driven Systems  

SciTech Connect

The objective of this project has been to develop computational methods that will enable more effective analysis of Accelerator Driven Systems (ADS). The work is centered at the University of Missouri at Rolla, with a subcontract at Northwestern University, and close cooperation with the Nuclear Engineering Division at Argonne National Laboratory. The work has fallen into three categories. First, the treatment of the source for neutrons originating from the spallation target which drives the neutronics calculations of the ADS. Second, the generalization of the nodal variational method to treat the R-Z geometry configurations frequently needed for scoping calculations in Accelerator Driven Systems. Third, the treatment of void regions within variational nodal methods as needed to treat the accelerator beam tube.

Nicholas Tsoulfanidis; Elmer Lewis

2005-02-09

442

Topical Issues for Particle Acceleration Mechanisms in Astrophysical Shocks  

E-print Network

Particle acceleration at plasma shocks appears to be ubiquitous in the universe, spanning systems in the heliosphere, supernova remnants, and relativistic jets in distant active galaxies and gamma-ray bursts. This review addresses some of the key issues for shock acceleration theory that require resolution in order to propel our understanding of particle energization in astrophysical environments. These include magnetic field amplification in shock ramps, the non-linear hydrodynamic interplay between thermal ions and their extremely energetic counterparts possessing ultrarelativistic energies, and the ability to inject and accelerate electrons in both non-relativistic and relativistic shocks. Recent observational developments that impact these issues are summarized. While these topics are currently being probed by astrophysicists using numerical simulations, they are also ripe for investigation in laboratory experiments, which potentially can provide valuable insights into the physics of cosmic shocks.

Matthew G. Baring

2006-11-05

443

Applications of the ARGUS code in accelerator physics  

SciTech Connect

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

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

1993-12-31

444

SuperB Progress Report for Accelerator  

SciTech Connect

This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around the world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national laboratories. In Italy these may include INFN Frascati and the University of Pisa, in the United States SLAC, LBNL, BNL and several universities, in France IN2P3, LAPP, and Grenoble, in Russia BINP, in Poland Krakow University, and in the UK the Cockcroft Institute. The construction time for this collider is a total of about four years. The new tunnel can be bored in about a year. The new accelerator components can be built and installed in about 4 years. The shipping of components from PEP-II at SLAC to Italy will take about a year. A new linac and damping ring complex for the injector for the rings can be built in about three years. The commissioning of this new accelerator will take about a year including the new electron and positron sources, new linac, new damping ring, new beam transport lines, two new collider rings and the Interaction Region. The new particle physics detector can be commissioned simultaneously with the accelerator. Once beam collisions start for particle physics, the luminosity will increase with time, likely reaching full design specifications after about two to three years of operation. After construction, the operation of the collider will be the responsibility of the Italian INFN governmental agency. The intent is to run this accelerator about ten months each year with about one month for accelerator turn-on and nine months for colliding beams. The collider will need to operate for about 10 years to provide the required 50 ab{sup -1} requested by the detector collaboration. Both beams as anticipated in this collider will have properties that are excellent for use as sources for synchrotron radiation (SR). The expected photon properties are comparable to those of PETRA-3 or NSLS-II. The beam lines and user facilities needed to carry out this SR program are being investigated.

Biagini, M.E.; Boni, R.; Boscolo, M.; Buonomo, B.; Demma, T.; Drago, A.; Esposito, M.; Guiducci, S.; Mazzitelli, G.; Pellegrino, L.; Preger, M.A.; Raimondi, P.; Ricci, R.; Rotundo, U.; Sanelli, C.; Serio, M.; Stella, A.; Tomassini, S.; Zobov, M.; /Frascati; Bertsche, K.; Brachman, A.; /SLAC /Novosibirsk, IYF /INFN, Pisa /Pisa U. /Orsay, LAL /Annecy, LAPP /LPSC, Grenoble /IRFU, SPP, Saclay /DESY /Cockroft Inst. Accel. Sci. Tech. /U. Liverpool /CERN

2012-02-14

445

The world deep underground laboratories  

NASA Astrophysics Data System (ADS)

This paper is an introduction to a series of coordinated articles of an EPJ Plus Focus Point on underground physics laboratories, written by the directors of the larger ones and by the coordinators of the principal new projects. The paper is largely based on the text of my lecture Perspectives of underground physics, given at the Enrico Fermi Varenna International School, Course CLXXXII (2011), Neutrino physics and astrophysics, reproduced here by permission of the Italian Physical Society. Underground laboratories provide the low radioactive background environment necessary to explore the highest energy scales that cannot be reached with accelerators, by searching for extremely rare phenomena. Experiments range from the direct search of the dark-matter particles that constitute the largest fraction of matter in the Universe, to the exploration of the properties of the neutrinos, the most elusive of the known particles and which might be particle and antiparticle at the same time, to the investigation on why our universe contains only matter and almost no antimatter, and much more.

Bettini, A.

2012-09-01

446

Purdue Rare Isotope Measurement Laboratory  

NASA Astrophysics Data System (ADS)

The Purdue Rare Isotope Measurement Laboratory (PRIME Lab) is a dedicated research and service facility for accelerator mass spectrometry. AMS is an ultra-sensitive analytical technique used to measure low levels of long-lived cosmic-ray-produced and anthropogenic radionuclides, and rare trace elements. We measure 10Be (T1/2 = 1.5 My), 26Al (.702 My), 36Cl (.301 My), and 129I (16 My), in geologic samples. Applications include dating the cosmic-ray-exposure time of rocks on Earth's surface, determining rock and sediment burial ages, measuring the erosion rates of rocks and soils, and tracing and dating ground water. We perform sample preparation and separation chemistries for these radio-nuclides for our internal research activities and for those external researchers not possessing this capability. Our chemical preparation laboratories also serve as training sites for members of the geoscience community developing these techniques at their institutions. Research at Purdue involves collaborators among members of the Purdue Departments of Physics, Earth and Atmospheric Sciences, Chemistry, Agronomy, and Anthropology. We also collaborate and serve numerous scientists from other institutions. We are currently in the process of modernizing the facility with the goals of higher precision for routinely measured radio-nuclides, increased sample throughput, and the development of new measurement capabilities for the geoscience community.

Caffee, M.; Elmore, D.; Granger, D.; Muzikar, P.

2002-12-01

447

Space Acceleration Measurement System (SAMS)/Orbital Acceleration Research Experiment (OARE)  

NASA Technical Reports Server (NTRS)

The Life and Microgravity Spacelab (LMS) payload flew on the Orbiter Columbia on mission STS-78 from June 20th to July 7th, 1996. The LMS payload on STS-78 was dedicated to life sciences and microgravity experiments. Two accelerometer systems managed by the NASA Lewis Research Center (LERC) flew to support these experiments, namely the Orbital Acceleration Research Experiment (OARE) and the Space Acceleration Measurements System (SAMS). In addition, the Microgravity Measurement Assembly (NOAA), managed by the European Space Research and Technology Center (ESA/ESTEC), and sponsored by NASA, collected acceleration data in support of the experiments on-board the LMS mission. OARE downlinked real-time quasi-steady acceleration data, which was provided to the investigators. The SAMS recorded higher frequency data on-board for post-mission analysis. The MMA downlinked real-time quasi-steady as well as higher frequency acceleration data, which was provided to the investigators. The Principal Investigator Microgravity Services (PIMS) project at NASA LERC supports principal investigators of microgravity experiments as they evaluate the effects of varying acceleration levels on their experiments. A summary report was prepared by PIMS to furnish interested experiment investigators with a guide to evaluate the acceleration environment during STS-78, and as a means of identifying areas which require further study. The summary report provides an overview of the STS-78 mission, describes the accelerometer systems flown on this mission, discusses some specific analyses of the accelerometer data in relation to the various activities which occurred during the mission, and presents plots resulting from these analyses as a snapshot of the environment during the mission. Numerous activities occurred during the STS-78 mission that are of interest to the low-gravity community. Specific activities of interest during this mission were crew exercise, radiator deployment, Vernier Reaction Control System (VRCS) reboost, venting operations, Flight Control System (FCS) checkout, rack excitation, operation of the Life Sciences Laboratory Equipment Refrigerator/Freezer (LSLE R/F), operation of the JSC Projects Centrifuge, crew sleep, and attitude changes. The low-gravity environment related to these activities is discussed in the summary report.

Hakimzadeh, Roshanak

1998-01-01

448

Lepton accelerators and radiation sources: R and D investment at BNL  

SciTech Connect

Brookhaven National Laboratory (BNL) has shown its determination to remain at the forefront of accelerator based science through its continued investment in long range accelerator R and D. The laboratory has a broad program in accelerator technology development including projects such as high {Tc} magnets at RHIC, Siberian Snakes at the AGS, brightness upgrades on the NSLS storage ring, and spallation source R and D in several departments. This report focuses on a segment of the overall program: the lepton accelerator and coherent radiation source R and D at the laboratory. These efforts are aimed at (1) development of high brightness electron beams, (2) novel acceleration techniques, (3) seeded Free Electron Laser (FEL) development, and (4) R and D for a muon collider. To pursue these objectives, BNL ha over the past decade introduced new organizational arrangements. The BNL Center for Accelerator Physics (CAP) is an interdepartmental unit dedicated to promoting R and D which, cannot be readily conducted within the programs of operating facilities. The Accelerator Test Facility (ATF) is managed by CAP and NSLS as a user facility dedicated to accelerator and beam physics problems of interest to both the High Energy Physics and Basic Energy Sciences programs of the DOE. Capitalizing on these efforts, the Source Development Laboratory (SDL) was established by the NSLS to facilitate coordinated development of sources and experiments to produce and utilize coherent sub-picosecond synchrotron radiation. This White Paper describes the programs being pursued at CAP, ATF and SDL aimed at advancing basic knowledge of lepton accelerators and picosecond radiation sources.

Ben-Zvi, I.; Fernow, R.; Gallardo, J.; Hart, M.; Hastings, J.; Johnson, E.; Krinsky, S.; Palmer, R.; Yu, L.H.

1997-03-01

449

DIANA - A deep underground accelerator for nuclear astrophysics experiments  

NASA Astrophysics Data System (ADS)

DIANA (Dakota Ion Accelerator for Nuclear Astrophysics) is a proposed facility designed to be operated deep underground. The DIANA collaboration includes nuclear astrophysics groups from Lawrence Berkeley National Laboratory, Michigan State University, Western Michigan University, Colorado School of Mines, and the University of North Carolina, and is led by the University of Notre Dame. The scientific goals of the facility are measurements of low energy nuclear cross-sections associated with sun and pre-supernova stars in a laboratory setup at energies that are close to those in stars. Because of the low stellar temperatures associated with these environments, and the high Coulomb barrier, the reaction cross-sections are extremely low. Therefore these measurements are hampered by small signal to background ratios. By going underground the background due to cosmic rays can be reduced by several orders of magnitude. We report on the design status of the DIANA facility with focus on the 3 MV electrostatic accelerator.

Winklehner, Daniel; Lemut, Alberto; Leitner, Daniela; Couder, Manoel; Hodgkinson, Adrian; Wiescher, Michael

2013-04-01

450

Acceleration and radiation processes in controlled gradient gas jets  

NASA Astrophysics Data System (ADS)

The controlled gradient gas jet was designed, constructed and tested at the Naval Research Laboratory. The gas jet is using a laser generated shock wave to control the density gradient between vacuum and neutral gas. The length scale of the density gradient is fully controlled by the strength of the shock wave and can be varied continuously from under 10 ?m in case of strong shock to a 100 ?m for a weak shock wave. To verify the experimental results a simulation was run to model the system using a three-dimensional hydrodynamic code, SPARC, developed at the Naval Research Laboratory. Controlling the gas density gradient is important for electrons and protons acceleration, as well as for optical transition radiation generation. Experiments on using the controlled gradient gas jet and preliminary results on electron acceleration will be presented.

Kaganovich, Dmitri; Helle, Mike; Gordon, Daniel; Xie, Frank; Ting, Antonio

2011-11-01

451

DIANA - A deep underground accelerator for nuclear astrophysics experiments  

SciTech Connect

DIANA (Dakota Ion Accelerator for Nuclear Astrophysics) is a proposed facility designed to be operated deep underground. The DIANA collaboration includes nuclear astrophysics groups from Lawrence Berkeley National Laboratory, Michigan State University, Western Michigan University, Colorado School of Mines, and the University of North Carolina, and is led by the University of Notre Dame. The scientific goals of the facility are measurements of low energy nuclear cross-sections associated with sun and pre-supernova stars in a laboratory setup at energies that are close to those in stars. Because of the low stellar temperatures associated with these environments, and the high Coulomb barrier, the reaction cross-sections are extremely low. Therefore these measurements are hampered by small signal to background ratios. By going underground the background due to cosmic rays can be reduced by several orders of magnitude. We report on the design status of the DIANA facility with focus on the 3 MV electrostatic accelerator.

Winklehner, Daniel; Leitner, Daniela [Michigan State University, 640 S Shaw Lane, East Lansing MI 48824 (United States); Lemut, Alberto; Hodgkinson, Adrian [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720 (United States); Couder, Manoel; Wiescher, Michael [University of Notre Dame, Notre Dame, IN 46556 (United States)

2013-04-19

452

Use of Linear Induction Accelerators for Flash Radiography  

NASA Astrophysics Data System (ADS)

Induction accelerators have been used for over a decade as flash x-ray sources for radiography. A new machine is presently under construction at Los Alamos National Laboratory and a second machine is under design for installation adjacent to the first one to form the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility. This second accelerator will provide a 2 microsecond pulse which will be subdivided by a fast kicker system to provide a sequence of four or more 70 ns pulses along a single line of sight. An advanced system to provide multiple pulses over a longer time interval and over many lines of sight will be discussed along with the technological advances in solid-state pulsed power, fast kickers and target systems necessary to make the concept a reality. *This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No.W-7405-Eng-48.

Caporaso, George

1998-04-01

453

Development of X-band accelerating structures for high gradients  

NASA Astrophysics Data System (ADS)

Short copper standing wave (SW) structures operating at an X-band frequency have been recently designed and manufactured at the Laboratori Nazionali di Frascati of the Istituto Nazionale di Fisica Nucleare (INFN) using the vacuum brazing technique. High power tests of the structures have been performed at the SLAC National Accelerator Laboratory. In this manuscript we report the results of these tests and the activity in progress to enhance the high gradient performance of the next generation of structures, particularly the technological characterization of high performance coatings obtained via molybdenum sputtering.

Bini, S.; Chimenti, V.; Marcelli, A.; Palumbo, L.; Spataro, B.; A. Dolgashev, V.; Tantawi, S.; D. Yeremian, A.; Higashi, Y.; G. Grimaldi, M.; Romano, L.; Ruffino, F.; Parodi, R.

2012-07-01

454

New directions in linear accelerators  

SciTech Connect

Current work on linear particle accelerators is placed in historical and physics contexts, and applications driving the state of the art are discussed. Future needs and the ways they may force development are outlined in terms of exciting R and D challenges presented to today's accelerator designers. 23 references, 7 figures.

Jameson, R.A.

1984-01-01

455

Shadows of a maximal acceleration  

E-print Network

A quantum mechanical upper limit on the value of particle accelerations, or maximal acceleration (MA), is applied to compact stars. A few MA fermions are at most present in canonical white dwarfs and neutron stars. They drastically alter a star's stability conditions.

G. Papini

2002-11-04

456

Natural Acceleration: Supporting Creative Trajectories  

ERIC Educational Resources Information Center

"Natural acceleration" happens through an internal fire that burns to learn and may transcend school boundaries. Based on their passionate interests and connections with a domain, children who hunger for domain understandings outside school curricula require different types of acceleration, motivated by these interests. The lifeworks, domains, and…

Cohen, LeoNora M.

2011-01-01

457

Cosmic Acceleration from Elementary Interactions  

E-print Network

It is possible to generate an accelerated period of expansion from reasonable potentials acting between the universe particle constituents. The pressure of primordial nucleons interacting via a simple nuclear potential is obtained via Mayer's cluster expansion technique. The attractive part of the potential engenders a negative pressure and may therefore be responsible for the cosmic acceleration.

R. Aldrovandi; R. R. Cuzinatto; L. G. Medeiros

2005-12-22

458

Polarization of Dielectrics by Acceleration  

E-print Network

We argue that acceleration induces electric polarization in usual dielectrics. Both accelerations in superfluid participate in the medium polarization. Excitations contribution to the polarization is calculated at low temperatures. Estimates of the effect show order of magnitude agreement with recent experimental results on electric effect of superflow.

L. A. Melnikovsky

2005-05-04

459

Inductively Coupled Discharge Plasma Accelerator  

Microsoft Academic Search

Summary form only given. Electromagnetic acceleration for generating an electrically neutral, high flux plasma beam and a system for carrying out this method are studied for the semiconductor etching process having no charging damage and space missions. In the capacitively coupled discharge plasma accelerator, a certain amount of electrode sputtering is inevitable from the ion bombardment flux. This causes serious

V. N. Volynets; Yu. N. Tolmachev; V. G. Pashkovsky; Jinwoo Yoo

2005-01-01

460

Lorentz contraction and accelerated systems  

NASA Astrophysics Data System (ADS)

The paper discusses the problem of the Lorentz contraction in accelerated systems, in the context of the special theory of relativity. Equal proper accelerations along different world lines are considered, showing the differences arising when the world lines correspond to physically connected or disconnected objects. In all cases the special theory of relativity proves to be completely self-consistent.

Tartaglia, A.; Ruggiero, M. L.

2003-03-01

461

Solar Flares and particle acceleration  

E-print Network

prominent in X-rays, UV/EUV and radio . but can be seen from radio to 100 MeV #12;Solar flares and accelerated particles #12;Solar flares and accelerated particles From Emslie et al., 2004, 2005 Free magnetic

462

General purpose programmable accelerator board  

DOEpatents

A general purpose accelerator board and acceleration method comprising use of: one or more programmable logic devices; a plurality of memory blocks; bus interface for communicating data between the memory blocks and devices external to the board; and dynamic programming capabilities for providing logic to the programmable logic device to be executed on data in the memory blocks.

Robertson, Perry J. (Albuquerque, NM); Witzke, Edward L. (Edgewood, NM)

2001-01-01

463

Theme: Laboratory Instruction.  

ERIC Educational Resources Information Center

A series of theme articles discuss setting up laboratory hydroponics units, the school farm at the Zuni Pueblo in New Mexico, laboratory experiences in natural resources management and urban horticulture, the development of teaching labs at Derry (PA) High School, management of instructional laboratories, and industry involvement in agricultural…

Bruening, Thomas H.; And Others

1992-01-01

464

Good Laboratory Practice  

NASA Astrophysics Data System (ADS)

The principles of Good Laboratory Practice (GLP) in conjunction with the principles of Total Quality Management (see chapter 6) ensure the quality and reliability of the laboratory results, which in turn help to ensure the protection of the environment and human health and safety. A step further is the accreditation of laboratories to ISO 17025 (see chapter 2) to perform specified activities.

Hadjicostas, Evsevios

465

Oussama Khatib Robotics Laboratory  

E-print Network

Oussama Khatib Robotics Laboratory Department of Computer Science Stanford University Stanford, CA 94305, USA khatib@cs.stanford.edu Oliver Brock Laboratory for Perceptual Robotics Department of Computer Luis Sentis Sriram Viji Robotics Laboratory Department of Computer Science Stanford University Stanford

Sentis, Luis

466

Laboratory Activities in Israel  

ERIC Educational Resources Information Center

Laboratory activities have long had a distinctive and central role in the science curriculum, and science educators have suggested that many benefits accrue from engaging students in science laboratory activities. Many research studies have been conducted to investigate the educational effectiveness of laboratory work in science education in…

Mamlok-Naaman, Rachel; Barnea, Nitza

2012-01-01

467

FORMULARY FOR LABORATORY ANIMALS  

E-print Network

, and safety. In many clinical situations, laboratory animal veterinarians do not have available approved drugs in the Department of Laboratory Animal Science, SmithKline Beecham Pharmaceuticals Research and DevelopmentFORMULARY FOR LABORATORY ANIMALS SECOND EDITION Compiled by C. TERRANCE HAWK PhD, DVM, Dipl. ACLAM

Arnold, Jonathan

468

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Doing Business with NREL  

E-print Network

Future3 Commercialization and Deployment Accelerate commercialization and achieve widespread adoption technologies Accelerate the availability of next generation technologies #12;National Renewable Energy Laboratory Innovation for Our Energy Future EERE Technology Portal PFTT/Maturation Funding Industry Advisory

469

Integrated amplifier-accelerator system  

NASA Astrophysics Data System (ADS)

A theoretical investigation of the interaction of electrons with the electromagnetic wave in a microwave amplifier indicates that about 50% of the electrons are in fact accelerated in the amplification process. We analyze a system which consists of an amplifier immediately followed by an accelerator. Although we loose part of the electromagnetic power due to the impedance mismatch, the electrons remain bunched and trapped when entering the acceleration section so that the acceleration process is reasonably efficient. The electrons which lost energy in the amplifier section, practically do not participate in the interaction process, since their velocity mismatch is too large. With 1 kA, 0.85 MV electrons and Ez equals 0.6 MV/m at the input, 40.6 cm of amplification and 43.4 cm of acceleration, calculations show that at the output 6% of the electrons have energies between 8 and 16 MV.

Schaechter, Levi; Nation, John A.

1992-04-01

470

Particle Acceleration by Magnetic Reconnection  

NASA Astrophysics Data System (ADS)

Observational data require a rich variety of mechanisms to accelerate fast particles in astrophysical environmen