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Sample records for accelerator laboratory hall

  1. Laser-Induced Fluorescence Measurements within a Laboratory Hall Thruster (Postprint)

    National Research Council Canada - National Science Library

    Hargus, Jr., W. A; Cappelli, M. A

    1999-01-01

    In this paper, we describe the results of a study of laser induced fluorescence velocimetry of ionic xenon in the plume and interior acceleration channel of a laboratory Hall type thruster operating...

  2. A Small Modular Laboratory Hall Effect Thruster

    Science.gov (United States)

    Lee, Ty Davis

    Electric propulsion technologies promise to revolutionize access to space, opening the door for mission concepts unfeasible by traditional propulsion methods alone. The Hall effect thruster is a relatively high thrust, moderate specific impulse electric propulsion device that belongs to the class of electrostatic thrusters. Hall effect thrusters benefit from an extensive flight history, and offer significant performance and cost advantages when compared to other forms of electric propulsion. Ongoing research on these devices includes the investigation of mechanisms that tend to decrease overall thruster efficiency, as well as the development of new techniques to extend operational lifetimes. This thesis is primarily concerned with the design and construction of a Small Modular Laboratory Hall Effect Thruster (SMLHET), and its operation on argon propellant gas. Particular attention was addressed at low-cost, modular design principles, that would facilitate simple replacement and modification of key thruster parts such as the magnetic circuit and discharge channel. This capability is intended to facilitate future studies of device physics such as anomalous electron transport and magnetic shielding of the channel walls, that have an impact on thruster performance and life. Preliminary results demonstrate SMLHET running on argon in a manner characteristic of Hall effect thrusters, additionally a power balance method was utilized to estimate thruster performance. It is expected that future thruster studies utilizing heavier though more expensive gases like xenon or krypton, will observe increased efficiency and stability.

  3. Linear Accelerator Laboratory

    International Nuclear Information System (INIS)

    1976-01-01

    This report covers the activity of the Linear Accelerator Laboratory during the period June 1974-June 1976. The activity of the Laboratory is essentially centered on high energy physics. The main activities were: experiments performed with the colliding rings (ACO), construction of the new colliding rings and beginning of the work at higher energy (DCI), bubble chamber experiments with the CERN PS neutrino beam, counter experiments with CERN's PS and setting-up of equipment for new experiments with CERN's SPS. During this period a project has also been prepared for an experiment with the new PETRA colliding ring at Hamburg. On the other hand, intense collaboration with the LURE Laboratory, using the electron synchrotron radiation emitted by ACO and DCI, has been developed [fr

  4. Hall effects on MHD flow past an accelerated plate

    International Nuclear Information System (INIS)

    Soundalgekar, V.M.; Ravi, S.; Hiremath, S.B.

    1980-01-01

    An exact solution of the MHD flow of an incompressible, electrically conducting, viscous fluid past a uniformly accelerated plate is presented. The velocity profiles are shown graphically and the numerical values of axial and transverse components of skin friction are tabulated. At high values of the Hall parameter, ωtau, the velocity is found to be oscillatory near the plate. (author)

  5. Quadrupole magnetic mapping of the high resolution spectrometers of Thomas Jefferson National Accelerator Laboratory, Hall A. (Q.M.M. project: Quadrupole Magnetic Measurement)

    International Nuclear Information System (INIS)

    Quemener, Gilles

    1997-01-01

    This thesis describes the magnetic measurements that have been performed on the superconducting quadrupoles of the High Resolution Spectrometers of TJNAF, Hall A (USA), which are designed to measure particle momentum up to 4 GeV.c -1 with a σp/p = 10 -4 resolution. The mapping method is based on rotating coil technique, the originality being a segmentation of the probe along the quad axis. Together with an accurate magnet modelling, the measurement of the flux variations through the set of rotating coils allows to determine the magnetic field at each point. We use the 3D field formalism, i.e., the Fourier-Bessel expansion of the field obtained by solving the Laplace equation. We describe the QMM method and then the apparatus consisting in two probes of length 1.6 m and 3.2 m built to map the three quadrupoles Q1, Q2, Q3. Data processing uses Fourier analysis. The mapping of the Electron Arm took place in situ in 1996. A first set of results concerns integral measurements including the properties of excitation cycle of the magnets (saturation and hysteresis). Second set of results in terms of local field yields the 3D field maps of the quadrupoles. After having applied corrections to the data we obtain a local field accuracy of 5 Gauss on each component, i.e. an uncertainty of 5.10 -4 relative to the quadrupole central field. We use SNAKE ray-tracing code with the implementation of QMM field maps and obtain preliminary results on HRS optics. (author)

  6. Hall effects on MHD flow past an accelerated plate

    Directory of Open Access Journals (Sweden)

    Deka R.K.

    2008-01-01

    Full Text Available The simultaneous effects of rotation and Hall current on the hydromagnetic flow past an accelerated horizontal plate relative to a rotating fluid is presented. It is found that for given values of m (Hall parameter, M (Hartmann number and an imposed rotation parameter Ω satisfying Ω = M 2m/(1 + m2, the transverse motion (transverse to the main flow disappears and the fluid moves in the direction of the plate only. The effects of the parameters m, M and Ω on the axial and transverse velocity profiles are shown graphically, whereas the effects of the parameters on the skin-friction components are shown by tabular values.

  7. Hall A

    Data.gov (United States)

    Federal Laboratory Consortium — The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electroand photo-induced reactions at very high luminosity...

  8. Laboratory of acceleration mass spectrometry

    International Nuclear Information System (INIS)

    Hybler, P.; Chrapan, J.

    2002-01-01

    In this paper authors describe the principle of the method of acceleration mass spectrometry and the construction plans of this instrument at the Faculty of ecology and environmental sciences in Banska Stiavnica. Using of this instrument for radiocarbon dating is discussed. A review of laboratories with acceleration mass spectrometry is presented

  9. ATLAS accelerator laboratory report

    International Nuclear Information System (INIS)

    Den Hartog, P.

    1986-01-01

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

  10. Numerical investigation of closed-loop control for Hall accelerators

    International Nuclear Information System (INIS)

    Barral, S.; Miedzik, J.

    2011-01-01

    Low frequency discharge current oscillations in Hall accelerators are conventionally damped with external inductor-capacitor (LC) or resistor-inductor-capacitor (RLC) networks. The role of such network in the stabilization of the plasma discharge is investigated with a numerical model and the potential advantages of proportional-integral-derivative (PID) closed-loop control over RLC networks are subsequently assessed using either discharge voltage or magnetic field modulation. Simulations confirm the reduction of current oscillations in the presence of a RLC network, but suggest that PID control could ensure nearly oscillation-free operation with little sensitivity toward the PID settings.

  11. Integration Test of the High Voltage Hall Accelerator System Components

    Science.gov (United States)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Pinero, Luis; Peterson, Todd; Dankanich, John

    2013-01-01

    NASA Glenn Research Center is developing a 4 kilowatt-class Hall propulsion system for implementation in NASA science missions. NASA science mission performance analysis was completed using the latest high voltage Hall accelerator (HiVHAc) and Aerojet-Rocketdyne's state-of-the-art BPT-4000 Hall thruster performance curves. Mission analysis results indicated that the HiVHAc thruster out performs the BPT-4000 thruster for all but one of the missions studied. Tests of the HiVHAc system major components were performed. Performance evaluation of the HiVHAc thruster at NASA Glenn's vacuum facility 5 indicated that thruster performance was lower than performance levels attained during tests in vacuum facility 12 due to the lower background pressures attained during vacuum facility 5 tests when compared to vacuum facility 12. Voltage-Current characterization of the HiVHAc thruster in vacuum facility 5 showed that the HiVHAc thruster can operate stably for a wide range of anode flow rates for discharge voltages between 250 and 600 volts. A Colorado Power Electronics enhanced brassboard power processing unit was tested in vacuum for 1,500 hours and the unit demonstrated discharge module efficiency of 96.3% at 3.9 kilowatts and 650 volts. Stand-alone open and closed loop tests of a VACCO TRL 6 xenon flow control module were also performed. An integrated test of the HiVHAc thruster, brassboard power processing unit, and xenon flow control module was performed and confirmed that integrated operation of the HiVHAc system major components. Future plans include continuing the maturation of the HiVHAc system major components and the performance of a single-string integration test.

  12. The Brookhaven National Laboratory Accelerator Test Facility

    International Nuclear Information System (INIS)

    Batchelor, K.

    1992-01-01

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies

  13. On electrostatic acceleration of plasmas with the Hall effect using electrode shaping

    International Nuclear Information System (INIS)

    Wang, Zhehui; Barnes, Cris W.

    2001-01-01

    Resistive magnetohydrodynamics (MHD) is used to model the electromagnetic acceleration of plasmas in coaxial channels. When the Hall effect is considered, the inclusion of resistivity is necessary to obtain physically meaningful solutions. In resistive MHD with the Hall effect, if and only if the electric current and the plasma flow are orthogonal (J·U=0), then there is a conserved quantity, in the form of U 2 /2+w+eΦ/M, along the flow, where U is the flow velocity, Φ is the electric potential, w is the enthalpy, and M is the ion mass. New solutions suggest that in coaxial geometry the Hall effect along the axial plasma flow can be balanced by proper shaping of conducting electrodes, with acceleration then caused by an electrostatic potential drop along the streamlines of the flow. The Hall effect separation of ion and electron flow then just cancels the electrostatic charge separation. Assuming particle ionization increases with energy density in the system, the resulting particle flow rates (J p ) scales with accelerator bias (V bias ) as J p ∝V bias 2 , exceeding the Child--Langmuir limit. The magnitude of the Hall effect (as determined by the Morozov Hall parameter, Ξ, which is defined as the ratio of electric current to particle current) is related to the energy needed for the creation of each ion--electron pair

  14. Hall MHD Stability and Turbulence in Magnetically Accelerated Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    H. R. Strauss

    2012-11-27

    The object of the research was to develop theory and carry out simulations of the Z pinch and plasma opening switch (POS), and compare with experimental results. In the case of the Z pinch, there was experimental evidence of ion kinetic energy greatly in excess of the ion thermal energy. It was thought that this was perhaps due to fine scale turbulence. The simulations showed that the ion energy was predominantly laminar, not turbulent. Preliminary studies of a new Z pinch experiment with an axial magnetic field were carried out. The axial magnetic is relevant to magneto - inertial fusion. These studies indicate the axial magnetic field makes the Z pinch more turbulent. Results were also obtained on Hall magnetohydrodynamic instability of the POS.

  15. Accelerator timing at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Oerter, B.; Conkling, C.R.

    1995-01-01

    Accelerator timing at Brookhaven National Laboratory has evolved from multiple coaxial cables transmitting individual pulses in the original Alternating Gradient Synchrotron (AGS) design, to serial coded transmission as the AGS Booster was added. With the implementation of this technology, the Super Cycle Generator (SCG) which synchronizes the AGS, Booster, LINAC, and Tandem accelerators was introduced. This paper will describe the timing system being developed for the Relativistic Heavy Ion Collider (RHIC)

  16. Comparison of Medium Power Hall Effect Thruster Ion Acceleration for Krypton and Xenon Propellants

    Science.gov (United States)

    2016-09-14

    Pumping is provided by four single-stage cryogenic panels (single-stage cold heads at 25 K) and one 50 cm two stage cryogenic pump (12 K). This vacuum...test chamber has a mea- sured pumping speed of 36 kL/s on xenon. The Hall thruster used in this study is a medium power laboratory Hall effect...The first compo- nent passes through a krypton opto-galvanic cell and is terminated by a beam dump . The opto-galvanic cell current is capacitively

  17. Breathing oscillations in enlarged cylindrical-anode-layer Hall plasma accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Geng, S. F.; Wang, C. X. [Southwestern Institute of Physics, Chengdu 610041 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Tang, D. L.; Qiu, X. M. [Southwestern Institute of Physics, Chengdu 610041 (China); Fu, R. K. Y. [Plasma Technology Limited, Festival Walk Tower, Tat Chee Avenue, Kowloon, Hong Kong (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2013-05-28

    Breathing oscillations in the discharge of an enlarged cylindrical-anode-layer Hall plasma accelerator are investigated by three-dimensional particle-in-cell (PIC) simulation. Different from the traditional breathing mode in a circular Hall plasma accelerator, the bulk plasma oscillation here is trigged by the potential barrier generated by the concentrated ion beam and substantial enough to compete with the anode voltage. The electric field near the anode is suppressed by the potential barrier thereby decreasing the electron density by {approx}36%. The discharge is restored to the normal level after the concentrated beam explodes and then it completes one cycle of electro-driven breathing oscillation. The breathing mode identified by the PIC simulation has a frequency range of {approx}156 kHz-{approx}250 kHz and does not vary monotonically with the discharge voltage.

  18. Qualitative models of magnetic field accelerated propagation in a plasma due to the Hall effect

    International Nuclear Information System (INIS)

    Kukushkin, A.B.; Cherepanov, K.V.

    2000-01-01

    Two qualitatively new models of accelerated magnetic field propagation (relative to normal diffusion) in a plasma due to the Hall effect are developed within the frames of the electron magnetic hydrodynamics. The first model is based on a simple hydrodynamic approach, which, in particular, reproduces the number of known theoretical results. The second one makes it possible to obtain exact analytical description of the basic characteristics of the magnetic field accelerated propagation in a inhomogeneous iso-thermic plasma, namely, the magnetic field front and its effective width [ru

  19. Operation of the Brookhaven national laboratory accelerator test facility

    International Nuclear Information System (INIS)

    Batchelor, K.; Ben-Zvi, I.; Botke, I.; Chou, T.S.; Fernow, R.; Fischer, J.; Fisher, A.; Gallardo, J.; Ingold, G.; Malone, R.; Palmer, R.; Parsa, Z.; Pogorelsky, I.; Rogers, J.; Sheehan, J.; Srinivasan-Rao, T.; Tsang, T.; Ulc, S.; Van Steenbergen, A.; Wang, X.J.; Woodle, M.; Yu, L.H.

    1992-01-01

    Early operation of the 50 MeV high brightness electron linac of the Accelerator Test Facility is described along with experimental data. This facility is designed to study new linear acceleration techniques and new radiation sources based on linacs in combination with free electron lasers. The accelerator utilizes a photo-excited, metal cathode, radio frequency electron gun followed by two travelling wave accelerating sections and an Experimental Hall for the study program. (Author) 5 refs., 4 figs., tab

  20. Operation of the Brookhaven National Laboratory Accelerator Test Facility

    International Nuclear Information System (INIS)

    Batchelor, K.; Ben-Zvi, I.; Botke, I.; Chou, T.S.; Fernow, R.; Fischer, J.; Fisher, A.; Gallardo, J.; Ingold, G.; Malone, R.; Palmer, R.; Parsa, Z.; Pogorelsky, I.; Rogers, J.; Sheehan, J.; Srinivasan-Rao, T.; Tsang, T.; Ulc, S.; van Steenbergen, A.; Wang, X.J.; Woodle, M.; Yu, L.H.

    1992-01-01

    Early operation of the 50 MeV high brightness electron linac of the Accelerator Test Facility is described along with experimental data. This facility is designed to study new linear acceleration techniques and new radiation sources based on linacs in combination with free electron lasers. The accelerator utilizes a photo-excited, metal cathode, radio frequency electron gun followed by two travelling wave accelerating sections and an Experimental Hall for the study program

  1. Performance and Environmental Test Results of the High Voltage Hall Accelerator Engineering Development Unit

    Science.gov (United States)

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

    2012-01-01

    NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.

  2. Accelerated laboratory weathering of acrylic lens materials

    Science.gov (United States)

    Arndt, Thomas; Richter, Steffen; Kogler, René; Pasierb, Mike; Walby, Christopher

    2015-09-01

    Flat samples from various poly(methyl methacrylate) (PMMA) formulations were subjected to outdoor weathering in Arizona and Florida, EMMAQUA® accelerated outdoor weathering, and two accelerated laboratory weathering procedures at 3 Sun irradiance which, imitate dry (Arizona) and wet (Florida) conditions. The main mode of degradation is yellowing and not the generation of haze for any weathering procedure within the investigated radiant exposure. Higher UV absorber concentrations lead to smaller changes in optical properties and in the resulting relative concentrator photovoltaic (CPV) module efficiencies. Comparison of sample properties after various weathering procedures reveals that the influence of weathering factors other than radiant exposure depends on the sample as well.

  3. Kansas State University accelerator laboratory upgrade

    International Nuclear Information System (INIS)

    Richard, P.

    1989-01-01

    The J.R. Macdonald Laboratory is undergoing a major upgrade of its facilities and capabilities. The laboratory is dedicated to the study of ion-atom collisions using highly charged ions from accelerators and/or ion sources. The mainstay of the laboratory over the last two decades has been a 6 MV tandem accelerator. It has been used to produce one- to a few-MeV/u highly charged ions for studying high energy atomic collisions, and to produce recoil ions from ocllisions with projectile ions for studying low energy atomic collisions. In order to enhance the capabilities of studying atomic collisions in these two energy regimes, we are constructing a superconducting LINAC booster to the tandem, and a stand-alone CRYEBIS source. The project, which is funded by the US Department of Energy, began in May 1985 with a May 1989 completion schedule. The upgrade includes a building addition, funded by the State of Kansas, to house the new facilities. The LINAC consists of a time-superbunching module, followed by three large cryostat modules each containing four superconducting resonators, and followed by an energy-rebunching module. The resonators are the split-ring superconducting Nb type designed and constructed at Argonne National Laboratory, and are presently being tested at KSU. The CRYEBIS source, which consists of a 1 m long 5 T superconducting solenoid with a high degree of straightness, is in the final stages of assembly. We have in operation a new computer network for data acquisition and analysis. A progress report on the status of the upgrade is presented. (orig.)

  4. Deeply virtual Compton scattering in the Hall A of Jefferson laboratory; Diffusion Compton profondement virtuelle dans le Hall A au Jefferson laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Munoz Camacho, C

    2005-12-15

    Generalized Parton Distributions (GPDs), introduced in the late 90's, provide a universal description of hadrons in terms of the underlying degrees of freedom of Quantum Chromodynamics: quarks and gluons. GPDs appear in a wide variety of hard exclusive reactions and the advent of high luminosity accelerator facilities has made the study of GPDs accessible to experiment. Deeply Virtual Compton Scattering (DVCS) is the golden process involving GPDs. The first dedicated DVCS experiment ran in the Hall A of Jefferson Lab in Fall 2004. An electromagnetic calorimeter and a plastic scintillator detector were constructed for this experiment, together with specific electronics and acquisition system. The experiment preparation, data taking and analysis are described in this document. Results on the absolute cross section difference for opposite beam helicities provide the first measurement of a linear combination of GPDs as a function of the momentum transfer to the nucleon. (author)

  5. Advanced laboratory for testing plasma thrusters and Hall thruster measurement campaign

    Directory of Open Access Journals (Sweden)

    Szelecka Agnieszka

    2016-06-01

    Full Text Available Plasma engines are used for space propulsion as an alternative to chemical thrusters. Due to the high exhaust velocity of the propellant, they are more efficient for long-distance interplanetary space missions than their conventional counterparts. An advanced laboratory of plasma space propulsion (PlaNS at the Institute of Plasma Physics and Laser Microfusion (IPPLM specializes in designing and testing various electric propulsion devices. Inside of a special vacuum chamber with three performance pumps, an environment similar to the one that prevails in space is created. An innovative Micro Pulsed Plasma Thruster (LμPPT with liquid propellant was built at the laboratory. Now it is used to test the second prototype of Hall effect thruster (HET operating on krypton propellant. Meantime, an improved prototype of krypton Hall thruster is constructed.

  6. High Voltage Hall Accelerator Propulsion System Development for NASA Science Missions

    Science.gov (United States)

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

    2013-01-01

    NASA Science Mission Directorates In-Space Propulsion Technology Program is sponsoring the development of a 3.8 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn Research Center and Aerojet are developing a high fidelity high voltage Hall accelerator (HiVHAc) thruster that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the HiVHAc engineering development unit thruster have been performed. In addition, the HiVHAc project is also pursuing the development of a power processing unit (PPU) and xenon feed system (XFS) for integration with the HiVHAc engineering development unit thruster. Colorado Power Electronics and NASA Glenn Research Center have tested a brassboard PPU for more than 1,500 hours in a vacuum environment, and a new brassboard and engineering model PPU units are under development. VACCO Industries developed a xenon flow control module which has undergone qualification testing and will be integrated with the HiVHAc thruster extended duration tests. Finally, recent mission studies have shown that the HiVHAc propulsion system has sufficient performance for four Discovery- and two New Frontiers-class NASA design reference missions.

  7. Integration Testing of a Modular Discharge Supply for NASA's High Voltage Hall Accelerator Thruster

    Science.gov (United States)

    Pinero, Luis R.; Kamhawi, hani; Drummond, Geoff

    2010-01-01

    NASA s In-Space Propulsion Technology Program is developing a high performance Hall thruster that can fulfill the needs of future Discovery-class missions. The result of this effort is the High Voltage Hall Accelerator thruster that can operate over a power range from 0.3 to 3.5 kW and a specific impulse from 1,000 to 2,800 sec, and process 300 kg of xenon propellant. Simultaneously, a 4.0 kW discharge power supply comprised of two parallel modules was developed. These power modules use an innovative three-phase resonant topology that can efficiently supply full power to the thruster at an output voltage range of 200 to 700 V at an input voltage range of 80 to 160 V. Efficiencies as high as 95.9 percent were measured during an integration test with the NASA103M.XL thruster. The accuracy of the master/slave current sharing circuit and various thruster ignition techniques were evaluated.

  8. Concentrated ion beam emitted from an enlarged cylindrical-anode-layer Hall plasma accelerator and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Geng, S. F.; Wang, C. X. [Southwestern Institute of Physics, Chengdu 610041 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Tang, D. L.; Qiu, X. M. [Southwestern Institute of Physics, Chengdu 610041 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2013-01-28

    An enlarged cylindrical-anode-layer Hall plasma accelerator with an outlet diameter of 150 mm is experimentally demonstrated to produce a concentrated ion beam, especially at a high discharge voltage, with a high current utilization efficiency of up to {approx}0.9. Numerical investigation based on the three-dimensional particle-in-cell method is performed to study the ion dynamics and elucidate the origin of the ion beam characteristics. The simulation results reveal that the equipotential lines play an important role in the surface near the anode emitting the ions. The ion emitting surface is determined by the magnetic field lines near the anode and the magnetic mirror contributes to the concentrated beam significantly. The high current utilization efficiency results from the appropriate obliquity of the magnetic mirror.

  9. Saskatchewan Accelerator Laboratory. Annual report 1986

    International Nuclear Information System (INIS)

    1986-01-01

    We have now completed the third year of the upgrading project to convert our conventional linear accelerator to a 300 MeV CW electron beam facility. The original Natural Sciences and Engineering Research Council (NSERC) grant in 1983 was for the following items: an energy compressor to improve the spectrum from the linac, a pulse stretcher ring to give ∼ 100% duty cycle, and a modern QDD spectrometer for efficient data taking. The status of all these items and other equipment funded for experiments is discussed in the text of this report. More details on the parameters of the various components may be found in previous annual reports (1984 and 1985). The 1984 report also describes the administrative structure of the project and how the performance of the laboratory is evaluated. Part of that supervisory structure is NSERC's Saskatchewan Advisory Committee. That committee visited the laboratory on 10-11 April 1986 and sent a satisfactory report to the presidents of NSERC and of the University of Saskatchewan. One more visit of this committee is expected at the completion of the project

  10. Saskatchewan Accelerator Laboratory annual report 1985

    International Nuclear Information System (INIS)

    Caplan, H.S.

    1985-11-01

    Last year was reported on the first year of the upgrading project to add an energy compressor system, a pulse stretcher ring, and a magnetic spectometer to our existing 300 MeV electron linear accelerator. As well as giving a description of the project, the 1984 Annual Report included statements on the function of the laboratory and how its performance is evaluated. This year two items have been added to the upgrading project. In April 1985 a photon tagging systems was funded by NSERC and in October 1985 a surplus 44 inch magnetic spectrometer was received from the High Energy Physics Laboratory at Stanford. The status of these two items is given later in this report. During 1985 there have been two visits of the Saskatchewan Advisory Committee: SAC 5 on 14th-15th March and SAC 6 on 24th-25th October. The committee has continued to report satisfactory progress in the project to the presidents of NSERC and the University of Saskatchewan

  11. Integration Tests of the 4 kW-class High Voltage Hall Accelerator Power Processing Unit with the HiVHAc and the SPT-140 Hall Effect Thrusters

    Science.gov (United States)

    Kamhawi, Hani; Pinero, Luis; Haag, Thomas; Huang, Wensheng; Ahern, Drew; Liang, Ray; Shilo, Vlad

    2016-01-01

    NASAs Science Mission Directorate is sponsoring the development of a 4 kW-class Hall propulsion system for implementation in NASA science and exploration missions. The main components of the system include the High Voltage Hall Accelerator (HiVHAc), an engineering model power processing unit (PPU) developed by Colorado Power Electronics, and a xenon flow control module (XFCM) developed by VACCO Industries. NASA Glenn Research Center is performing integrated tests of the Hall thruster propulsion system. This presentation presents results from integrated tests of the PPU and XFCM with the HiVHAc engineering development thruster and a SPT-140 thruster provided by Space System Loral. The results presented in this paper demonstrate thruster discharge initiation, open-loop and closed-loop control of the discharge current with anode flow for both the HiVHAc and the SPT-140 thrusters. Integrated tests with the SPT-140 thruster indicated that the PPU was able to repeatedly initiate the thrusters discharge, achieve steady state operation, and successfully throttle the thruster between 1.5 and 4.5 kW. The measured SPT-140 performance was identical to levels reported by Space Systems Loral.

  12. Deeply virtual Compton scattering in the Hall A of Jefferson laboratory

    International Nuclear Information System (INIS)

    Munoz Camacho, C.

    2005-12-01

    Generalized Parton Distributions (GPDs), introduced in the late 90's, provide a universal description of hadrons in terms of the underlying degrees of freedom of Quantum Chromodynamics: quarks and gluons. GPDs appear in a wide variety of hard exclusive reactions and the advent of high luminosity accelerator facilities has made the study of GPDs accessible to experiment. Deeply Virtual Compton Scattering (DVCS) is the golden process involving GPDs. The first dedicated DVCS experiment ran in the Hall A of Jefferson Lab in Fall 2004. An electromagnetic calorimeter and a plastic scintillator detector were constructed for this experiment, together with specific electronics and acquisition system. The experiment preparation, data taking and analysis are described in this document. Results on the absolute cross section difference for opposite beam helicities provide the first measurement of a linear combination of GPDs as a function of the momentum transfer to the nucleon. (author)

  13. Tandem Accelerator Laboratory annual report 1979

    International Nuclear Information System (INIS)

    Xenoulis, A.C.

    1980-01-01

    The activities presented cover the following topics: heavy ion reactions, gamma ray spectroscopy, applied atomic and nuclear physics, theoretical nuclear physics, data collection and processing, accelerator operation, as well as personnel and publications. (T.A.)

  14. Tandem Accelerator Laboratory annual report 1978

    International Nuclear Information System (INIS)

    1979-01-01

    The activities presented cover the following topics: heavy ion reactions, gamma ray spectroscopy, applied atomic and nuclear physics, theoretical nuclear physics, data collection and processing, accelerator operation, as well as personnel and publications. (T.A.)

  15. Tandem Accelerator Laboratory annual report 1980

    International Nuclear Information System (INIS)

    Anagnostatos, G.S.

    1981-01-01

    The activities presented cover the following topics: heavy ion reactions, gamma ray spectroscopy, applied atomic and nuclear physics, theoretical nuclear physics, data collection and processing development, accelerator operation, as well as personnel and publications. (T.A.)

  16. Experimental setup for deeply virtual Compton scattering (DVCS) experiment in hall A at Jefferson Laboratory

    International Nuclear Information System (INIS)

    Camsonne, A.

    2005-11-01

    The Hall A Deeply Virtual Compton Scattering (DVCS) experiment used the 5.757 GeV polarized electron beam available at Jefferson Laboratory and ran from september until december 2004. Using the standard Hall A left high resolution spectrometer three kinematical points were taken at a fixed x b (jorken) = 0.32 value for three Q 2 values: 1.5 GeV 2 , 1.91 GeV 2 , 2.32 GeV 2 . An electromagnetic Lead Fluoride calorimeter and a proton detector scintillator array designed to work at a luminosity of 10 37 cm -2 s -1 were added to ensure the exclusivity of the DVCS reaction. In addition to the new detectors new custom electronics was used: a calorimeter trigger module which determines if an electron photon coincidence has occurred and a sampling system allowing to deal with pile-up events during the offline analysis. Finally the data from the kinematic at Q 2 = 2.32 GeV 2 and s = 5.6 GeV 2 allowed to get a preliminary result for the exclusive π 0 electroproduction on the proton. (author)

  17. Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase III: Comparison of Theory with Experiment

    Science.gov (United States)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.

    2012-01-01

    A proof-of-principle effort to demonstrate a technique by which erosion of the acceleration channel in Hall thrusters of the magnetic-layer type can be eliminated has been completed. The first principles of the technique, now known as "magnetic shielding," were derived based on the findings of numerical simulations in 2-D axisymmetric geometry. The simulations, in turn, guided the modification of an existing 6-kW laboratory Hall thruster. This magnetically shielded (MS) thruster was then built and tested. Because neither theory nor experiment alone can validate fully the first principles of the technique, the objective of the 2-yr effort was twofold: (1) to demonstrate in the laboratory that the erosion rates can be reduced by >order of magnitude, and (2) to demonstrate that the near-wall plasma properties can be altered according to the theoretical predictions. This paper concludes the demonstration of magnetic shielding by reporting on a wide range of comparisons between results from numerical simulations and laboratory diagnostics. Collectively, we find that the comparisons validate the theory. Near the walls of the MS thruster, theory and experiment agree: (1) the plasma potential has been sustained at values near the discharge voltage, and (2) the electron temperature has been lowered by at least 2.5-3 times compared to the unshielded (US) thruster. Also, based on carbon deposition measurements, the erosion rates at the inner and outer walls of the MS thruster are found to be lower by at least 2300 and 1875 times, respectively. Erosion was so low along these walls that the rates were below the resolution of the profilometer. Using a sputtering yield model with an energy threshold of 25 V, the simulations predict a reduction of 600 at the MS inner wall. At the outer wall ion energies are computed to be below 25 V, for which case we set the erosion to zero in the simulations. When a 50-V threshold is used the computed ion energies are below the threshold at both

  18. X-ray K-edge analysis of drain lines in Wilhelm Hall, Ames Laboratory

    International Nuclear Information System (INIS)

    Jensen, T.; Whitmore, C.; Iowa State Univ., Ames, IA

    1999-01-01

    From August 12--27, 1998 X-ray K-edge measurements were made on drain lines in seven rooms in Wilhelm Hall, Ames Laboratory. The purpose of these measurements was to determine the extent of thorium (and other heavy metal) contamination inside these pipes. The K-edge method is a noninvasive inspection technique that can provide accurate quantification of heavy metal contamination interior to an object. Of the seven drain lines inspected, one was found to have no significant contamination, three showed significant thorium deposits, two showed mercury contamination, and one line was found to contain mercury, thorium and uranium. The K-edge measurements were found to be consistent with readings from hand-held survey meters, and provided much greater detail on the location and amount of heavy metal contamination

  19. Hall C

    Data.gov (United States)

    Federal Laboratory Consortium — Hall C's initial complement of equipment (shown in the figure), includes two general-purpose magnetic spectrometers. The High Momentum Spectrometer (HMS) has a large...

  20. Accelerator safety program at the Lawrence Livermore Laboratory

    International Nuclear Information System (INIS)

    Graham, C.L.

    1976-01-01

    A proposed accelerator safety standard for the Lawrence Livermore Laboratory (LLL) is given. All accelerators will comply with this standard when it is included in the LLL Health and Safety Manual. The radiation alarm and radiation safety system for a radiography facility are also described

  1. Runtime accelerator configuration tools at Jefferson Laboratory

    International Nuclear Information System (INIS)

    Tiefenback, M.G.; Doolittle, L.; Benesch, J.F.

    1997-01-01

    RF and magnet system configuration and monitoring tools are being implemented at Jefferson Lab to improve system reliability and reduce operating costs. They are prototype components of the Momentum Management System being developed. The RF is of special interest because it affects the momentum and momentum spread of the beam, and because of the immediate financial benefit of managing the klystron DC supply power. The authors describe present and planned monitoring of accelerating system parameters, use of these data, RF system performance calculations, and procedures for magnet configuration for handling beam of any of five beam energies to any of three targets

  2. Experimental Verification of the Hall Effect during Magnetic Reconnection in a Laboratory Plasma

    International Nuclear Information System (INIS)

    Yang Ren; Masaaki Yamada; Stefan Gerhardt; Hantao Ji; Russell Kulsrud; Aleksey Kuritsyn

    2005-01-01

    In this letter we report a clear and unambiguous observation of the out-of-plane quadrupole magnetic field suggested by numerical simulations in the reconnecting current sheet in the Magnetic Reconnection Experiment (MRX). Measurements show that the Hall effect is large in collisionless regime and becomes small as the collisionality increases, indicating that the Hall effect plays an important role in collisionless reconnection

  3. Single String Integration Test of the High Voltage Hall Accelerator System

    Science.gov (United States)

    Kamhawi, Hani; Haag, Thomas W.; Huang, Wensheng; Pinero, Luis; Peterson, Todd; Shastry, Rohit

    2013-01-01

    HiVHAc Task Objectives:-Develop and demonstrate low-power, long-life Hall thruster technology to enable cost effective EP for Discovery-class missions-Advance the TRL level of potential power processing units and xenon feed systems to integrate with the HiVHAc thruster.

  4. Photon and π"0 electroproduction at Jefferson Laboratory-Hall A

    International Nuclear Information System (INIS)

    Defurne, Maxime

    2015-01-01

    Defined in the mid 90's, the generalized parton distributions (GPDs) represent a higher level of information than the form factors and parton distribution functions: indeed they encapsulate the correlation between the fraction of longitudinal momentum and the transverse position of the partons inside the nucleon. Consequently we can access the distribution of the partons in the transverse plane according to their longitudinal momentum. Moreover we can derive the total angular orbital momentum of quarks thanks to Ji's sum rule. Experimentally, we access the GPDs through the study of deep exclusive processes (asymmetries, cross sections,...). A worldwide experimental program started in the early 2000's. This thesis presents two data analyses carried on two data sets from experiments running at Jefferson laboratory - Hall A in 2004 and 2010. From the 2004 data set, we have extracted unpolarized and polarized photon electroproduction cross sections. A careful study of the systematic errors has greatly improved the quality of the results. They seem to indicate the necessity to take into account target-mass and finite-t corrections up to twist-4. From the 2010 data set, we have performed the first separation of the longitudinal and transverse responses of neutral pion electroproduction. The results confirm the assumption of a significant contribution of the transverse response although kinematically suppressed with respect to the longitudinal response. These results of high precision validate the GPD approach and will allow to improve the existing models. (author) [fr

  5. Cyclotron Development and Technical Aspects on Accelerator Based Laboratory Development

    International Nuclear Information System (INIS)

    Sunarhadijoso

    2000-01-01

    BATAN is planning to establish an accelerator-based laboratory at P3TM Yogyakarta as an effort in the development and use of accelerator technology for improving industrial performance and public welfare. This paper reviews several aspects of cyclotron technology and describes the combination of a linear accelerator - cyclotron system as an alternative to be considered in the planing of the laboratory. The progress of cyclotron technology is discussed covering three generations, i.e. conventional cyclotron, synchrocyclotron and AVF cyclotron generations. The planning should not consider the accelerator application for radioisotope production because it is established in Serpong with the existing negative ion cyclotron. The proposed facility at P3TM may comprise two linear accelerators coupled with a positive ion cyclotron of synchrocyclotron generation. In fact, the attachment of the synchrocyclotron unit is flexible and it can be installed subsequently if the higher energy particle beam, which can not be produced by the linear accelerators, is extremely needed. Some technical aspects related to ion beam application, building construction and infrastructure, human resources, and specification of function test are discussed for additional information in the implementation of the planning. (author)

  6. Beat-wave accelerator studies at the Rutherford Appleton Laboratory

    International Nuclear Information System (INIS)

    Lawson, J.D.

    1985-01-01

    The study carried out in 1982-83 at the Rutherford Appleton Laboratory to examine how one might use the beat-wave principle to construct a useful high energy accelerator is reviewed, and comments are made on later developments. A number of problems are evident to which solutions cannot at present be foreseen. (author)

  7. 15-year-activity of Electron Linear Accelerator Laboratory

    International Nuclear Information System (INIS)

    Karolczak, S.

    1999-01-01

    The purchase of the Russian Electron Linear Accelerator ELU-6E by Institute of Radiation Technique of Lodz Technical University in 1978 started the activity of the ELA Laboratory. The accelerator itself and many additional scientific equipment designed and built during past 15 years have became the basic investigation tool for the ITR now. The most important measuring systems based on electron beam as irradiation source are: pulse radiolysis system with detection in IR, UV and visible region of the spectra, radiation induced conductometry, Faraday chamber and computerized data acquisition and processing system

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

    Science.gov (United States)

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

    2014-08-01

    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.

  9. Electroproduction of neutral pions in the Hall A at the Jefferson Laboratory; Electroproduction de pions neutres dans le Hall A au Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Fuchey, Eric [Blaise Pascal Univ., Aubiere (France)

    2010-06-01

    The past decade has seen a strong evolution of the study of the hadron structure through exclusive processes, allowing to access to a more complete description of this structure. Exclusive processes include DVCS (Deeply Virtual Compton Scattering) as well as hard exclusive meson production. This document is particularly focussed on the latter, and more particularly on exclusive neutral pion production. In this thesis is described the analysis of triple coincidence events H(e, e'γγ)X, which were a consequent by-product of the DVCS experiment which occured during Fall 2004 at Jefferson Lab Hall A, to extract the ep → epπ0 cross section. This cross section has been measured at two values of four-momentum transfer Q2 = 1.9 GeV2 and Q2 = 2.3 GeV2. The statistical precision for these measurements is achieved at better than 5 %. The kinematic range allows to study the evolution of the extracted cross section as a function of Q2 and W. Results are be confronted with Regge inspired calculations and Generalized (GPD) predictions. An intepretation of our

  10. McMaster Accelerator Laboratory. Annual report 1987

    International Nuclear Information System (INIS)

    1987-01-01

    During the past year the trend has continued of diversification of the research programmes in the laboratory. Research using the techniques of accelerator mass spectrometry is flourishing and there is increased activity in the fields of surface science and nuclear medicine. The nuclear physics activity continues strong but at a reduced level. The FN accelerators performed excellently during the year and the nuclear physics programme benefitted from the acquisition of a computer-controlled analysing-magnet NMR. Surface science at McMaster University is involved with the Ontario Government Centre of Excellence in Materials Science. This will involve new equipment for studies in molecular beam epitaxy. The research studies in brain function is also another growing area in the laboratory

  11. Accelerator facility in a small laboratory of a private university

    International Nuclear Information System (INIS)

    Washio, Masakazu

    2005-01-01

    Washio laboratory in Waseda University started the project team in 1999 and finished tests of all machines in 2000. High brilliant soft X-ray generation by inverse Compton scattering and the pico-second pulse radiolysis system were developed. The time profile of creation of hydrated electron was obtained by the system in 2003. Determination of accelerator spec and cooperation of University, and set up of accelerator, preparation of research group, cooperation with KEK, student training, beam experiments, experiments and future is stated. This system was constructed and operated by many students in his laboratory, and supported by many members of KEK-ATF, Waseda University, Sumitomo Heavy Industries, Ltd., High Technology Research Center Project of Ministry of Education, Culture, Sports, Science and Technology, and Grant-in-Aid for Scientific Research of Japan Society for the Promotion Science. (S.Y.)

  12. Tailoring of targets for a tandem accelerator laboratory

    International Nuclear Information System (INIS)

    Sletten, G.

    1976-01-01

    The organization of a target laboratory serving the nuclear physics research at a tandem van de graaff accelerator is described. Emphasis is put on the layout of the laboratory and the mode of operation. The working force is about 40 h per week shared by two technical assistants, and they are supervised by a physicist who on the average spends about 1/3 of his time on target-related problems. Selected topics like heavy ion sputtering of actinides and the preparation of multilayer targets are described in detail. (author)

  13. Technology transfer from accelerator laboratories (challenges and opportunities)

    International Nuclear Information System (INIS)

    Verma, V.K.; Gardner, P.L.

    1994-06-01

    It is becoming increasingly evident that technology transfer from research laboratories must be a key element of their comprehensive strategic plans. Technology transfer involves using a verified and organized knowledge and research to develop commercially viable products. Management of technology transfer is the art of organizing and motivating a team of scientists, engineers and manufacturers and dealing intelligently with uncertainties. Concurrent engineering is one of the most effective approaches to optimize the process of technology transfer. The challenges, importance, opportunities and techniques of transferring technology from accelerator laboratories are discussed. (author)

  14. Kyushu University Tandem Accelerator Laboratory report, 1988-1990

    International Nuclear Information System (INIS)

    Sagara, Kenshi; Morinobu, Shunpei

    1991-03-01

    Ten years have elapsed since the first beam was obtained from the Kyushu University tandem accelerator. Although the laboratory has achieved successful scientific results, the performance of the accelerator has been on a decline mainly due to the aging. In the last two and a half years, the tandem accelerator has suffered from the fall of terminal voltage to around 8 MV. However, the experimental studies in the laboratory have been active. The utilization of the polarized beams of protons and deuterons to study the scattering of the p+d system, the use of heavy ion beam for the systematic search for the molecular resonance in relatively heavy systems and for the study on reaction mechanism, the use of both light and heavy ion beams for the studies on nuclear engineering, material science and geological science and so on were carried out. The gamma ray spectroscopic study on the state near yrast line was largely hampered by the accelerator troubles, instead, the collaboration with the Niels Bohr Institute provided a wonderful research ground for the studies. (K.I.)

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

    International Nuclear Information System (INIS)

    1995-04-01

    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

  16. Felsenkeller shallow-underground accelerator laboratory for nuclear astrophysics

    Science.gov (United States)

    Bemmerer, D.; Cowan, T. E.; Gohl, S.; Ilgner, C.; Junghans, A. R.; Reinhardt, T. P.; Rimarzig, B.; Reinicke, S.; Röder, M.; Schmidt, K.; Schwengner, R.; Stöckel, K.; Szücs, T.; Takács, M.; Wagner, A.; Wagner, L.; Zuber, K.

    2015-05-01

    Favored by the low background in underground laboratories, low-background accelerator-based experiments are an important tool to study nuclear reactions involving stable charged particles. This technique has been used for many years with great success at the 0.4 MV LUNA accelerator in the Gran Sasso laboratory in Italy, proteced from cosmic rays by 1400 m of rock. However, the nuclear reactions of helium and carbon burning and the neutron source reactions for the astrophysical s-process require higher beam energies than those available at LUNA. Also the study of solar fusion reactions necessitates new data at higher energies. As a result, in the present NuPECC long range plan for nuclear physics in Europe, the installation of one or more higher-energy underground accelerators is strongly recommended. An intercomparison exercise has been carried out using the same HPGe detector in a typical nuclear astrophysics setup at several sites, including the Dresden Felsenkeller underground laboratory. It was found that its rock overburden of 45m rock, together with an active veto against the remaining muon flux, reduces the background to a level that is similar to the deep underground scenario. Based on this finding, a used 5 MV pelletron tandem with 250 μA upcharge current and external sputter ion source has been obtained and transported to Dresden. Work on an additional radio-frequency ion source on the high voltage terminal is underway. The project is now fully funded. The installation of the accelerator in the Felsenkeller is expected for the near future. The status of the project and the planned access possibilities for external users will be reported.

  17. Post-accelerator issues at the IsoSpin Laboratory

    International Nuclear Information System (INIS)

    Chattopadhyay, S.; Nitschke, J.M.

    1994-05-01

    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-β, 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

  18. Linear accelerator laboratory progress report: July 1983 - October 1985

    International Nuclear Information System (INIS)

    1987-01-01

    Different experiments presented are Asterix at Lear (CERN), DM2 at DCI (Orsay), NA3 and NA9 at SPS (CERN), NA9 at SPS, Cello at Desy (Hamburg), NA14 and NA31 at SPS, UA2 at SpantipS (CERN), the experiment ''proton meanlife'' at the underground laboratory of Modane. Experiments in preparation are Aleph (Lep), Delphi (Lep), H1. Technical projects are researches in acceleration techniques, experimental data acquisition with Fastbus standard and event analysis in 3D graphics [fr

  19. Radiocarbon accelerator mass spectrometry (AMS) sample preparation laboratory in Brazil

    International Nuclear Information System (INIS)

    Macario, Kita D.; Gomes, Paulo R. S.; Anjos, Roberto M. dos; Linares, Roberto; Queiroz, Eduardo; Oliveira, Fabiana M. de; Cardozo, Laio; Carvalho, Carla R.A.

    2011-01-01

    Full text: For decades Accelerator Mass Spectrometry has been widely used for radiocarbon measurements all over the world with application in several fields of science from archaeology to geosciences. This technique provides ultrasensitive analysis of reduced size samples or even specific compounds since sample atoms are accelerated to high energies and measured using nuclear particle detectors. Sample preparation is extremely important for accurate radiocarbon measurement and includes chemical pre-treatment to remove all possible contaminants. For beam extraction in the accelerator ion source, samples are usually converted to graphite. In this work we report a new radiocarbon sample preparation facility installed at the Physics Institute of Universidade Federal Fluminense (UFF), in Brazil. At the Nuclear Chronology Laboratory (LACRON) samples are chemically treated and converted to carbon dioxide by hydrolysis or combustion. A stainless steel based vacuum line was constructed for carbon dioxide separation and graphitization is performed in sealed quartz tubes in a muffle oven. Successful graphite production is important to provide stable beam currents and to minimize isotopic fractionation. Performance tests for graphite production are currently under way and isotopic analysis will soon be possible with the acquisition of a Single Stage AMS System by our group. The Single Stage Accelerator produced by National Electrostatic Corporation is a 250 kV air insulated accelerator especially constructed to measure the amount of 14 C in small modern graphite samples to a precision of 0.3 % or better. With the installation of such equipment in the first half of 2012, UFF will be ready to perform the 14C -AMS technique. (author)

  20. A plasma deflagration accelerator as a platform for laboratory astrophysics

    Science.gov (United States)

    Underwood, Thomas C.; Loebner, Keith T. K.; Cappelli, Mark A.

    2017-06-01

    The replication of astrophysical flows in the laboratory is critical for isolating particular phenomena and dynamics that appear in complex, highly-coupled natural systems. In particular, plasma jets are observed in astrophysical contexts at a variety of scales, typically at high magnetic Reynolds number and driven by internal currents. In this paper, we present detailed measurements of the plasma parameters within deflagration-produced plasma jets, the scaling of these parameters against both machine operating conditions and the corresponding astrophysical phenomena. Using optical and spectroscopic diagnostics, including Schlieren cinematography, we demonstrate the production of current-driven plasma jets of ∼100 km/s and magnetic Reynolds numbers of ∼100, and discuss the dynamics of their acceleration into vacuum. The results of this study will contribute to the reproduction of various types of astrophysical jets in the laboratory and indicate the ability to further probe active research areas such as jet collimation, stability, and interaction.

  1. Experimental setup for deeply virtual Compton scattering (DVCS) experiment in hall A at Jefferson Laboratory; Dispositif experimental pour la diffusion Compton virtuelle dans le regime profondement inelastique dans le hall A au Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Camsonne, A

    2005-11-15

    The Hall A Deeply Virtual Compton Scattering (DVCS) experiment used the 5.757 GeV polarized electron beam available at Jefferson Laboratory and ran from september until december 2004. Using the standard Hall A left high resolution spectrometer three kinematical points were taken at a fixed x{sub b}(jorken) = 0.32 value for three Q{sup 2} values: 1.5 GeV{sup 2}, 1.91 GeV{sup 2}, 2.32 GeV{sup 2}. An electromagnetic Lead Fluoride calorimeter and a proton detector scintillator array designed to work at a luminosity of 10{sup 37} cm{sup -2}s{sup -1} were added to ensure the exclusivity of the DVCS reaction. In addition to the new detectors new custom electronics was used: a calorimeter trigger module which determines if an electron photon coincidence has occurred and a sampling system allowing to deal with pile-up events during the offline analysis. Finally the data from the kinematic at Q{sup 2} = 2.32 GeV{sup 2} and s = 5.6 GeV{sup 2} allowed to get a preliminary result for the exclusive {pi}{sup 0} electroproduction on the proton. (author)

  2. McMaster Accelerator Laboratory. Annual report 1988

    International Nuclear Information System (INIS)

    1988-01-01

    This Annual Report summarizes the research activities at the McMaster Accelerator Laboratory. Included are reports of work carried out during the period of November 1987 to September 1988 with separate subsections for Nuclear Physics Research, Accelerator Mass Spectrometry, Atomic, Molecular and Material Sciences, and Nuclear Medicine. A number of the research reports are of a preliminary nature and the authors should be contacted before results are quoted. Details of the facility and its operation follow with reports of our computer control group. Finally there is a list of publications covering the period January 1987 to September 1988. The two major accelerators continue to operate very well. The model FN tandem Van De Graaff was used by four research groups for routine runs at a terminal voltage of 10 MV or higher with serveral days of experiments at 11 MV. The variety and stability of heavy ion beams continues to increase. Our technical staff have done an excellent job of improving and upgrading this facility and are to be congratulated on a job well done

  3. A new pulsed neutron source at Pohang accelerator laboratory

    International Nuclear Information System (INIS)

    Kim, G.N.; Choi, J.Y.; Cho, M.H.; Ko, I.S.; Namkung, W.; Chang, J.H.

    1997-01-01

    The main efforts in the field of promoting the nuclear data activities to support the national nuclear development program being realized in the Republic of Korea are discussed. Within this program frameworks the Korea Atomic Energy Research Institute (KAERI) will play a central role and the Pohang Accelerator Laboratory (PAL) will construct a pulsed neutron source facility. The 100 MeV electron linac based on the existing equipment including Toshiba E3712 klystron, 200 MW modulator and constant gradient accelerating sections is designed in PAL. The schematic diagram and the main parameters of the linac consisting of a triode type electron gun (EIMAC Y824), an S-band prebuncher and buncher, two accelerating sections and various other components are considered. The construction of the linac already started in early 1997 is planned to be completed in 1998. The target room, TOF beam lines and detector stations will be constructed by the end of 1999. The first experiments with the intense pulsed neutrons produced at the facility considered are expected by 2000

  4. The cyclotron laboratory and the RFQ accelerator in Bern

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  5. The cyclotron laboratory and the RFQ accelerator in Bern

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  6. PREFACE: Acceleration and radiation generation in space and laboratory plasmas

    Science.gov (United States)

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

    1994-01-01

    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

  7. An improved data acquisition system at the Saskatchewan Accelerator Laboratory

    International Nuclear Information System (INIS)

    Norum, W.E.

    1994-01-01

    An improved data acquisition system has been in service at the Saskatchewan Accelerator Laboratory for the past 14 months. The system has shown itself to be reliable and easy to use having collected over 800 gigabytes of data for a number of experiments. The system is based on a VME front end computer acquiring data from CAMAC and FASTBUS modules and forwarding the data via an Ethernet connection to an acquisition workstation for archiving and on-line analysis. A multiprocessor real-time operating system in the front end computer makes increasing the performance of the system a simple matter of adding an additional processor to the VME chassis. Experimenters need only write a high-level description of their experiment which is transformed into a C program for the front end computer by a translation program. Special requirements are met by facilities for direct inclusion of user C or FORTRAN code

  8. Environmental Survey preliminary report, Fermi National Accelerator Laboratory, Batavia, Illinois

    International Nuclear Information System (INIS)

    1988-10-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the US Department of Energy (DOE) Fermi National Accelerator Laboratory (Fermilab), conducted September 14 through 25, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual participants for the Survey team are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Fermilab. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations performed at Fermilab, and interviews with site personnel. 110 refs., 26 figs., 41 tabs

  9. Environmental Survey preliminary report, Fermi National Accelerator Laboratory, Batavia, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    1988-10-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the US Department of Energy (DOE) Fermi National Accelerator Laboratory (Fermilab), conducted September 14 through 25, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual participants for the Survey team are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Fermilab. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations performed at Fermilab, and interviews with site personnel. 110 refs., 26 figs., 41 tabs.

  10. Proposed Casey's Pond Improvement Project, Fermi National Accelerator Laboratory

    International Nuclear Information System (INIS)

    1995-05-01

    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

  11. Los Alamos National Laboratory accelerated tru waste workoff strategies

    International Nuclear Information System (INIS)

    Kosiewicz, S.T.; Triay, I.R.; Rogers, P.Z.; Christensen, D.V.

    1997-01-01

    During 1996, the Los Alamos National Laboratory (LANL) developed two transuranic (TRU) waste workoff strategies that were estimated to save $270 - 340M through accelerated waste workoff and the elimination of a facility. The planning effort included a strategy to assure that LANL would have a significant quantity (3000+ drums) of TRU waste certified for shipment to the Waste Isolation Pilot Plant (WIPP) beginning in April of 1998, when WIPP was projected to open. One of the accelerated strategies can be completed in less than ten years through a Total Optimization of Parameters Scenario (open-quotes TOPSclose quotes). open-quotes TOPSclose quotes fully utilizes existing LANL facilities and capabilities. For this scenario, funding was estimated to be unconstrained at $23M annually to certify and ship the legacy inventory of TRU waste at LANL. With open-quotes TOPSclose quotes the inventory is worked off in about 8.5 years while shipping 5,000 drums per year at a total cost of $196M. This workoff includes retrieval from earthen cover and interim storage costs. The other scenario envisioned funding at the current level with some increase for TRUPACT II loading costs, which total $16M annually. At this funding level, LANL estimates it will require about 17 years to work off the LANL TRU legacy waste while shipping 2,500 drums per year to WIPP. The total cost will be $277M. This latter scenario decreases the time for workoff by about 19 years from previous estimates and saves an estimated $190M. In addition, the planning showed that a $70M facility for TRU waste characterization was not needed. After the first draft of the LANL strategies was written, Congress amended the WIPP Land Withdrawal Act (LWA) to accelerate the opening of WIPP to November 1997. Further, the No Migration Variance requirement for the WIPP was removed. This paper discusses the LANL strategies as they were originally developed. 1 ref., 3 figs., 2 tabs

  12. Tiger Team Assessment of the Fermi National Accelerator Laboratory

    International Nuclear Information System (INIS)

    1992-06-01

    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 ampersand 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 ampersand 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 ampersand H requirements, root causes for noncompliance, adequacy of DOE and contractor ES ampersand H management programs, response actions to address the identified problem areas, and DOE-wide ES ampersand H compliance trends and root causes

  13. McMaster Accelerator Laboratory annual report, 1980

    International Nuclear Information System (INIS)

    1980-01-01

    This Annual Report covers research carried out on the laboratory's three accelerators during the period November 1979 to October 1980. The contents include reports of the research completed or in progress during the year, a summary of the operation and development of the facilities, a list of persons associated with the laboratory and a list of publications for the last two years. A major new development during the year has been the development and use of a new multiplicity filter. This consists of a detector array built on the Lotus beam line together with the associated electronics to allow detection of mulitple gamma-ray coincidences. This allows study of high-spin states of rotational bands in nuclei. Measurements have allowed identification of bands in 159 Tm. A large part of the research programme has been based on reaction studies with beams of both polarized and unpolarized protons and deuterons. A short period of operation with a tritium beam took place in order to implant tritium in both Si(Li) and Ge(Li) detectors for further studies of the β-decay spectrum but no other experimental work took place with this beam. A major run with tritium is planned for early in 1981. There has been considerable collaboration with colleagues in other institutions with experiments being carried out at both McMaster and other institutions

  14. Free convective heat transfer with hall effects, heat absorption and chemical reaction over an accelerated moving plate in a rotating system

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S.M., E-mail: hussain.modassir@yahoo.com [Department of Mathematics, OP Jindal University, Raigarh 496109 (India); Jain, J., E-mail: jj.28481@gmail.com [Department of Mathematics, OP Jindal University, Raigarh 496109 (India); Seth, G.S., E-mail: gsseth_ism@yahoo.com [Department of Applied Mathematics, Indian School of Mines, Dhanbad 826004 (India); Rashidi, M.M., E-mail: mm_rashidi@yahoo.com [Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management System, Tongji University, Shanghai 201804 (China)

    2017-01-15

    The unsteady MHD free convective heat and mass transfer flow of an electrically conducting, viscous and incompressible fluid over an accelerated moving vertical plate in the presence of heat absorption and chemical reaction with ramped temperature and ramped surface concentration through a porous medium in a rotating system is studied, taking Hall effects into account. The governing equations are solved analytically with the help of Laplace transform technique. The unified closed-form expressions are obtained for fluid velocity, fluid temperature, species concentration, skin friction, Nusselt number and Sherwood numbers. The effects of various parameters on fluid velocity, fluid temperature and species concentration are discussed by graphs whereas numerical values of skin friction, Nusselt and Sherwood numbers are presented in tabular form for different values of pertinent flow parameters. The numerical results are also compared with free convective flow near ramped temperature plate with ramped surface concentration with the corresponding flow near isothermal plate with uniform surface concentration. - Highlights: • Magnetic field, Hall current, rotation and chemical reaction play vital role on flow field. • Hall current tends to accelerate secondary fluid velocity in the boundary layer region. • Rotation tends to retard primary fluid velocity throughout the boundary layer region. • Rotation and chemical reaction tend to enhance primary skin friction. • Solutal buoyancy force and permeability of medium reduce primary skin friction.

  15. Laboratory Test of Newton's Second Law for Small Accelerations

    International Nuclear Information System (INIS)

    Gundlach, J. H.; Schlamminger, S.; Spitzer, C. D.; Choi, K.-Y.; Woodahl, B. A.; Coy, J. J.; Fischbach, E.

    2007-01-01

    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 -14 m/s 2

  16. Effect of Hall current and chemical reaction on MHD flow along an exponentially accelerated porous flat plate with internal heat absorption/generation

    International Nuclear Information System (INIS)

    Rath, Pravat Kumar; Dash, G.C.; Patra, Ajit Kumar

    2010-01-01

    Effect of Hall current on the unsteady free convection flow of an electrically conducting incompressible viscous fluid past an exponentially accelerated vertical porous flat plate with internal heat absorption/generation in the presence of foreign gases (such as H 2 , CO 2 , H 2 O, NH 3 ) and chemical reaction has been investigated. An uniform magnetic field transverse to the plate has been applied. The effects of the Hall current m, the hydromagnetic parameter Mt, the chemical reaction parameter K c the Grashof number for heat transfer G r , the Grashof number for mass transfer G c , the Schmidt number S c , the Prandtl number P r and the transpiration parameter α are discussed in detail. (author)

  17. Panel discussion on laboratory accelerator programs: present and future

    International Nuclear Information System (INIS)

    Richter, B.

    1986-09-01

    The present SLAC accelerator program is summarized briefly, and the future of electron-positron colliders is discussed. Present activities discussed include the PEP storage ring, the SPEAR storage ring, the Linear Accelerator, and the SLAC Linear Collider (SLC) project. Future prospects include a larger scale linear collider. The stability requirements on acceleration are briefly discussed

  18. Experimental study of the Hall effect and electron diffusion region during magnetic reconnection in a laboratory plasma

    International Nuclear Information System (INIS)

    Ren Yang; Yamada, Masaaki; Ji Hantao; Dorfman, Seth; Gerhardt, Stefan P.; Kulsrud, Russel

    2008-01-01

    The Hall effect during magnetic reconnection without an external guide field has been extensively studied in the laboratory plasma of the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)] by measuring its key signature, an out-of-plane quadrupole magnetic field, with magnetic probe arrays whose spatial resolution is on the order of the electron skin depth. The in-plane electron flow is deduced from out-of-plane magnetic field measurements. The measured in-plane electron flow and numerical results are in good agreement. The electron diffusion region is identified by measuring the electron outflow channel. The width of the electron diffusion region scales with the electron skin depth (∼5.5-7.5c/ω pe ) and the peak electron outflow velocity scales with the electron Alfven velocity (∼0.12-0.16V eA ), independent of ion mass. The measured width of the electron diffusion region is much wider and the observed electron outflow is much slower than those obtained in 2D numerical simulations. It is found that the classical and anomalous dissipation present in the experiment can broaden the electron diffusion region and slow the electron outflow. As a consequence, the electron outflow flux remains consistent with numerical simulations. The ions, as measured by a Mach probe, have a much wider outflow channel than the electrons, and their outflow is much slower than the electron outflow everywhere in the electron diffusion region

  19. Formerly utilized MED/AEC sites Remedial Action Program. Report of the decontamination of Jones Chemical Laboratory, Ryerson Physical Laboratory, and Eckhart Hall, the University of Chicago, Chicago, Illinois

    International Nuclear Information System (INIS)

    Wynuveen, R.A.; Smith, W.H.; Sholeen, C.M.; Flynn, K.F.

    1984-08-01

    The US Department of Energy (DOE) has implemented a program to decontaminate radioactively contaminated sites that were formerly utilized by the Manhattan Engineer District (MED) and/or the Atomic Energy Commission (AEC) for activities that included handling of radioactive material. This program is referred to as the ''Formerly Utilized Sites Remedial Action Program'' (FUSRAP). Among these sites are Jones Chemical Laboratory, Ryerson Physical Laboratory, Kent Chemical Laboratory, and Eckhart Hall of The University of Chicago, Chicago, Illinois. Since 1977, the University of Chicago decontaminated Kent Chemical Laboratory as part of a facilities renovation program. All areas of Eckhart Hall, Ryerson Physical Laboratory, and Jones Chemical Laboratory that had been identified as contaminated in excess of current guidelines in the 1976-1977 surveys were decontaminated to levels where no contamination could be detected relative to natural backgrounds. All areas that required defacing to achieve this goal were restored to their original condition. The radiological evaluation of the sewer system, based primarily on the radiochemical analyses of sludge and water samples, indicated that the entire sewer system is potentially contaminated. While this evaluation was defined as part of this project, the decontamination of the sewer system was not included in the purview of this effort. The documentation included in this report substantiates the judgment that all contaminated areas identified in the earlier reports in the three structures included in the decontamination effort (Eckhart Hall, Ryerson Physical Laboratory, and Jones Chemical Laboratory) were cleaned to levels commensurate with release for unrestricted use

  20. Vacuum Systems Consensus Guideline for Department of Energy Accelerator Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Casey,R.; Haas, E.; Hseuh, H-C.; Kane, S.; Lessard, E.; Sharma, S.; Collins, J.; Toter, W. F.; Olis, D. R.; Pushka, D. R.; Ladd, P.; Jobe, R. K.

    2008-09-09

    and inspections of materials, in-process fabrications, non-destructive tests, and acceptance test. (3) Documentation, traceability, and accountability must be maintained for each unique pressure vessel or system, including descriptions of design, pressure conditions, testing, inspection, operation, repair, and maintenance. The purpose of this guideline is to establish a set of expectations and recommendations which will satisfy the requirements for vacuum vessels in general and particularly when an equivalent level of safety as required by 10 CFR 851 must be provided. It should be noted that these guidelines are not binding on DOE Accelerator Laboratories and that other approaches may be equally acceptable in addressing the Part 851 requirements.

  1. Operational status of the Brookhaven National Laboratory Accelerator Test Facility

    International Nuclear Information System (INIS)

    Batchelor, K.; Ben-Zvi, I.; Fernow, R.C.; Fischer, A.S.; Gallardo, J.; Jialin, Xie; Kirk, H.G.; Malone, R.G.; Parsa, Z.; Palmer, R.B.; Rao, T.; Rogers, J.; Sheehan, J.; Tsang, T.Y.F.; Ulc, S.; van Steenbergen, A.; Woodle, M.; Zhang, R.S.; Bigio, I.; Kurnit, N.; Shimada, T.; McDonald, K.T.; Russel, D.P.; Jiang, Z.Y.; Pellegrini, C.; Wang, X.J.

    1990-01-01

    Initial design parameters and early operational results of a 50 MeV high brightness electron linear accelerator are described. The system utilizes a radio frequency electron gun operating at a frequency of 2.856 GHz and a nominal output energy of 4.5 MeV followed by two, 2π/3 mode, disc loaded, traveling wave accelerating sections. The gun cathode is photo excited with short (6 psec) laser pulses giving design peak currents of a few hundred amperes. The system will be utilized to carry out infra-red FEL studies and investigation of new high gradient accelerating structures

  2. Darmstadt Linear Accelerator (DALINAC) Research Laboratory. Status report - July 1988

    International Nuclear Information System (INIS)

    Anon.

    1988-07-01

    The status of the DALINAC project is reviewed. The accelerator and the experimental facilities are described, and a free-electron laser project is considered. Furthermore, experiments on inelastic electron scattering on nuclei and atomic systems are listed. (HSI)

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

    International Nuclear Information System (INIS)

    Peterson, Randolph S.; Berggren, Karl K.; Mondol, Mark

    2011-01-01

    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.

  4. Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

    Science.gov (United States)

    Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

    2014-01-01

    The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thruster's anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization and acceleration zones upstream shifting as a function of increased background pressure.

  5. Accelerator development at Bates

    International Nuclear Information System (INIS)

    Sargent, C.P.

    1983-01-01

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

  6. Felsenkeller shallow-underground accelerator laboratory for nuclear astrophysics

    Directory of Open Access Journals (Sweden)

    Bemmerer D.

    2015-01-01

    Based on this finding, a used 5 MV pelletron tandem with 250 μA upcharge current and external sputter ion source has been obtained and transported to Dresden. Work on an additional radio-frequency ion source on the high voltage terminal is underway. The project is now fully funded. The installation of the accelerator in the Felsenkeller is expected for the near future. The status of the project and the planned access possibilities for external users will be reported.

  7. McMaster Accelerator Laboratory annual report, 1984

    International Nuclear Information System (INIS)

    1984-11-01

    Summaries of projects in progress constitute the major portion of this report. The tandem accelerator operated well during most of the year, with a number of heavy ion runs carried out at 10.44 MV. Tritium beams and polarized deuteron beams have been used extensively. Experiments using the multiplicity filter to study high spin states continue. An experiment was carried out relating to the search for a neutrino mass. Activity also continued in other areas of physics, engineering and medicine

  8. McMaster Accelerator Laboratory annual report, 1983

    International Nuclear Information System (INIS)

    1983-11-01

    The FN tandem accelerator has been upgraded with new spiral inclined field tubes and a pelletron charging system. Terminal voltages of 10 MV are obtained regularly, and improved injection optics allow higher transmission and increased beam currents. Much work has been done on tritium-induced reactions and with polarized deuteron beams. The study of nuclear phenomena at high spin and nuclear temperature using the multiplicity filter continues. Several experiments touch on other areas of physics, engineering, and medicine

  9. Operational status of the Brookhaven National Laboratory Accelerator Test Facility

    International Nuclear Information System (INIS)

    Batchelor, K.; Ben-Zvi, I.; Chou, T.S.; Los Alamos National Lab., NM; Princeton Univ., NJ

    1989-01-01

    Design and operation of a 50 MeV Electron Linear Accelerator utilizing a low emittance (γ var epsilon = 5 to 10 mm-mrad) radio frequency gun operating at an output energy of 5 MeV and a charge of 1 nC is described. Design calculations and early radio frequency measurements and operational experience with the electron gun utilizing a dummy copper cathode in place of the proposed photocathode emitter are given. 6 refs., 9 figs., 1 tab

  10. Development of laboratory acceleration test method for service life prediction of concrete structures

    International Nuclear Information System (INIS)

    Cho, M. S.; Song, Y. C.; Bang, K. S.; Lee, J. S.; Kim, D. K.

    1999-01-01

    Service life prediction of nuclear power plants depends on the application of history of structures, field inspection and test, the development of laboratory acceleration tests, their analysis method and predictive model. In this study, laboratory acceleration test method for service life prediction of concrete structures and application of experimental test results are introduced. This study is concerned with environmental condition of concrete structures and is to develop the acceleration test method for durability factors of concrete structures e.g. carbonation, sulfate attack, freeze-thaw cycles and shrinkage-expansion etc

  11. HYDROMECHANICS LABORATORY

    Data.gov (United States)

    Federal Laboratory Consortium — Naval Academy Hydromechanics LaboratoryThe Naval Academy Hydromechanics Laboratory (NAHL) began operations in Rickover Hall in September 1976. The primary purpose of...

  12. Formerly utilized MED/AEC sites Remedial Action Program. Report of the decontamination of Jones Chemical Laboratory, Ryerson Physical Laboratory, and Eckhart Hall, the University of Chicago, Chicago, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Wynuveen, R.A.; Smith, W.H.; Sholeen, C.M.; Flynn, K.F.

    1984-08-01

    The US Department of Energy (DOE) has implemented a program to decontaminate radioactively contaminated sites that were formerly utilized by the Manhattan Engineer District (MED) and/or the Atomic Energy Commission (AEC) for activities that included handling of radioactive material. This program is referred to as the ''Formerly Utilized Sites Remedial Action Program'' (FUSRAP). Among these sites are Jones Chemical Laboratory, Ryerson Physical Laboratory, Kent Chemical Laboratory, and Eckhart Hall of The University of Chicago, Chicago, Illinois. Since 1977, the University of Chicago decontaminated Kent Chemical Laboratory as part of a facilities renovation program. All areas of Eckhart Hall, Ryerson Physical Laboratory, and Jones Chemical Laboratory that had been identified as contaminated in excess of current guidelines in the 1976-1977 surveys were decontaminated to levels where no contamination could be detected relative to natural backgrounds. All areas that required defacing to achieve this goal were restored to their original condition. The radiological evaluation of the sewer system, based primarily on the radiochemical analyses of sludge and water samples, indicated that the entire sewer system is potentially contaminated. While this evaluation was defined as part of this project, the decontamination of the sewer system was not included in the purview of this effort. The documentation included in this report substantiates the judgment that all contaminated areas identified in the earlier reports in the three structures included in the decontamination effort (Eckhart Hall, Ryerson Physical Laboratory, and Jones Chemical Laboratory) were cleaned to levels commensurate with release for unrestricted use.

  13. Fermi National Accelerator Laboratory Annual Program Review 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-01

    This book is submitted as a written adjunct to the 1993 Annual DOE High Energy Physics Program Review of Fermilab, scheduled for March 31-April 3. In it are described the functions and activities of the various Laboratory Divisions and Sections plus statements of plans and goals for the coming year. The Review Committee, as this goes to press, consists of·

  14. Fermi National Accelerator Laboratory Annual Program Review 1991

    Energy Technology Data Exchange (ETDEWEB)

    Appel, Jeffrey A. [Fermilab; Jovanovic, Drasko [Fermilab; Pordes, Stephen [Fermilab

    1991-01-01

    This book is submitted as a written adjunct to the Annual DOE High Energy Physics Program Review of Fermilab, scheduled this year for April 10-12, 1991. In it are described the functions and activities of the various Laboratory areas plus statements of plans and goals for the coming year.

  15. Accelerator-based techniques for the support of senior-level undergraduate physics laboratories

    International Nuclear Information System (INIS)

    Williams, J.R.; Clark, J.C.; Isaacs-Smith, T.

    2001-01-01

    Approximately three years ago, Auburn University replaced its aging Dynamitron accelerator with a new 2MV tandem machine (Pelletron) manufactured by the National Electrostatics Corporation (NEC). This new machine is maintained and operated for the University by Physics Department personnel, and the accelerator supports a wide variety of materials modification/analysis studies. Computer software is available that allows the NEC Pelletron to be operated from a remote location, and an Internet link has been established between the Accelerator Laboratory and the Upper-Level Undergraduate Teaching Laboratory in the Physics Department. Additional software supplied by Canberra Industries has also been used to create a second Internet link that allows live-time data acquisition in the Teaching Laboratory. Our senior-level undergraduates and first-year graduate students perform a number of experiments related to radiation detection and measurement as well as several standard accelerator-based experiments that have been added recently. These laboratory exercises will be described, and the procedures used to establish the Internet links between our Teaching Laboratory and the Accelerator Laboratory will be discussed

  16. Fermi National Accelerator Laboratory Annual Program Review 2000

    Energy Technology Data Exchange (ETDEWEB)

    2000-03-01

    This book is submitted as one written part of the 2000 Annual DOE High Energy Physics Program Review of Fermilab, scheduled March 22-24, 2000. In it are Director's Overview, some experimental highlights, discussions of several projects, and descriptions of the functions and activities of the four laboratory divisions. This book should be read in conjunction with the 2000 Fermilab Workbook and the review presentations (both in formal sessions and at the poster session).

  17. An Adaptive Laboratory Evolution Method to Accelerate Autotrophic Metabolism

    DEFF Research Database (Denmark)

    Zhang, Tian; Tremblay, Pier-Luc

    2018-01-01

    Adaptive laboratory evolution (ALE) is an approach enabling the development of novel characteristics in microbial strains via the application of a constant selection pressure. This method is also an efficient tool to acquire insights on molecular mechanisms responsible for specific phenotypes. ALE...... autotrophically and reducing CO2 into acetate more efficiently. Strains developed via this ALE method were also used to gain knowledge on the autotrophic metabolism of S. ovata as well as other acetogenic bacteria....

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2014-05-15

    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

  19. Formerly Utilized MED/AEC Sites Remedial Action Program. Project management plan for the decontamination of Jones Laboratory, Ryerson Physical Laboratory, and Eckhart Hall, the University of Chicago, Chicago, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, K.F.; Smith, W.H.; Wynveen, R.A.

    1984-01-01

    The Department of Energy (DOE) has in place a plan for the decontamination and decommissioning of contaminated sites that had been formerly utilized by the Manhattan Engineering District (MED) and/or the Atomic Energy Commission. This plan is referred to as the Formerly Utilized Sites Remedial Action Program (FUSRAP). Among these sites are Jones Laboratory, Ryerson Physical Laboratory and Eckhart Hall of The University of Chicago at Chicago, Illinois. This document represents the Project Management Plan for the decontamination of these facilities. 13 references, 3 figures, 1 table.

  20. Formerly Utilized MED/AEC Sites Remedial Action Program. Project management plan for the decontamination of Jones Laboratory, Ryerson Physical Laboratory, and Eckhart Hall, the University of Chicago, Chicago, Illinois

    International Nuclear Information System (INIS)

    Flynn, K.F.; Smith, W.H.; Wynveen, R.A.

    1984-01-01

    The Department of Energy (DOE) has in place a plan for the decontamination and decommissioning of contaminated sites that had been formerly utilized by the Manhattan Engineering District (MED) and/or the Atomic Energy Commission. This plan is referred to as the Formerly Utilized Sites Remedial Action Program (FUSRAP). Among these sites are Jones Laboratory, Ryerson Physical Laboratory and Eckhart Hall of The University of Chicago at Chicago, Illinois. This document represents the Project Management Plan for the decontamination of these facilities. 13 references, 3 figures, 1 table

  1. Investigation of the Effects of Cathode Flow Fraction and Position on the Performance and Operation of the High Voltage Hall Accelerator

    Science.gov (United States)

    Kamhawi, Hani; Huang, Wensheng; Haag, Thomas

    2014-01-01

    The National Aeronautics and Space Administration (NASA) Science Mission Directorate In- Space Propulsion Technology office is sponsoring NASA Glenn Research Center (GRC) to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. Tests were performed within NASA GRC Vacuum Facility 5 at background pressure levels that were six times lower than what has previously been attained in other vacuum facilities. A study was conducted to assess the impact of varying the cathode-to-anode flow fraction and cathode position on the performance and operational characteristics of the High Voltage Hall Accelerator (HiVHAc) thruster. In addition, the impact of injecting additional xenon propellant in the vicinity of the cathode was also assessed. Cathode-to-anode flow fraction sensitivity tests were performed for power levels between 1.0 and 3.9 kW. It was found that varying the cathode flow fraction from 5 to approximately 10% of the anode flow resulted in the cathode-to-ground voltage becoming more positive. For an operating condition of 3.8 kW and 500 V, varying the cathode position from a distance of closest approach to 600 mm away did not result in any substantial variation in thrust but resulted in the cathode-to-ground changing from -17 to -4 V. The change in the cathode-to-ground voltage along with visual observations indicated a change in how the cathode plume was coupling to the thruster discharge. Finally, the injection of secondary xenon flow in the vicinity of the cathode had an impact similar to increasing the cathode-to-anode flow fraction, where the cathode-to-ground voltage became more positive and discharge current and thrust increased slightly. Future tests of the HiVHAc thruster are planned with a centrally mounted cathode in order to further assess the impact of cathode position on thruster performance.

  2. Accelerator Laboratory of the University and the Technical University of Munich. Annual report 1992

    International Nuclear Information System (INIS)

    Korschinek, G.; Lutter, R.; Riess, F.

    1993-01-01

    This report contains extended abstracts about the work performed at the named laboratory together with a list of publications and reports. The abstracts concern experiments on nuclear reactions, nuclear spectroscopy, atomic physics, accelerator mass spectroscopy with heavy ions, and applications of nuclear techniques, theoretical work on nuclear reactions, nuclear structure, atomic physics, and astrophysics, developments of accelerators and radiation instrumentation, as well as data processing. (HSI)

  3. Semiconductor Electrical Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Electrical Measurements Laboratory is a research laboratory which complements the Optical Measurements Laboratory. The laboratory provides for Hall...

  4. Accelerator Mass Spectrometry at the Nuclear Science Laboratory: Applications to Nuclear Astrophysics

    Science.gov (United States)

    Collon, P.; Bauder, W.; Bowers, M.; Lu, W.; Ostdiek, K.; Robertson, D.

    The Accelerator Mass Spectrometry (AMS) program at the Nuclear Science Laboratory of the University of Notre Dame is focused on measurements related to galactic radioactivity and to nucleosynthesis of main stellar burning as well as the production of so called Short-Lived Radionuclides (SLRs) in the Early Solar System (ESS). The research program is based around the 11MV FN tandem accelerator and the use of the gas-filled magnet technique for isobar separation. Using a technique that evolved from radiocarbon dating, this paper presents a number of research programs that rely on the use of an 11MV tandem accelerator at the center of the AMS program.

  5. A new method of measuring gravitational acceleration in an undergraduate laboratory program

    Science.gov (United States)

    Wang, Qiaochu; Wang, Chang; Xiao, Yunhuan; Schulte, Jurgen; Shi, Qingfan

    2018-01-01

    This paper presents a high accuracy method to measure gravitational acceleration in an undergraduate laboratory program. The experiment is based on water in a cylindrical vessel rotating about its vertical axis at a constant speed. The water surface forms a paraboloid whose focal length is related to rotational period and gravitational acceleration. This experimental setup avoids classical source errors in determining the local value of gravitational acceleration, so prevalent in the common simple pendulum and inclined plane experiments. The presented method combines multiple physics concepts such as kinematics, classical mechanics and geometric optics, offering the opportunity for lateral as well as project-based learning.

  6. ACCELERATION OF LOS ALAMOS NATIONAL LABORATORY TRANSURANIC WASTE DISPOSITION

    International Nuclear Information System (INIS)

    O'Leary, Gerald A.

    2007-01-01

    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

  7. The target laboratory of the Pelletron Accelerator's facilities

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-05-06

    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.

  8. Technical Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-08-26

    Electrons can “surf” on waves of plasma – a hot gas of charged particles – gaining very high energies in very short distances. This approach, called plasma wakefield acceleration, has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider has been the focus of FACET, a National User Facility at SLAC. FACET used part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and their antimatter counterparts, positrons. Research into plasma wakefield acceleration was the primary motivation for constructing FACET. In April 2016, FACET operations came to an end to make way for the second phase of SLAC’s x-ray laser, the LCLS-II, which will use part of the tunnel occupied by FACET. FACET-II is a new test facility to provide the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II represents a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique.

  9. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    Sinclair, C.K.

    1998-01-01

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented. copyright 1998 American Institute of Physics

  10. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

  11. Particle-in-cell simulation for the effect of segmented electrodes near the exit of an aton-type Hall thruster on ion focusing acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Yu, D.R.; Qing, S.W.; Liu, H.; Li, H. [Lab. of Plasma Propulsion, Harbin Institute of Technology (China)

    2011-12-15

    The effect of floating conductive electrodes near the channel exit of an Aton-type Hall thruster on ion focusing acceleration is studied by simulating the two-dimensional plasma flow with a fully kinetic Particle-in-Cell method for the gas flow rate j{sub a} ranged in 1{proportional_to}3 mg/s. Numerical results show that low-emissive electrodes can reduce plume divergence if the electrode length is less than 2 mm due to the low secondary electron emissive characteristic, but widen plume in all the gas flow rate range if the electrode length is greater than 2mm since the conductive property of segmented electrodes trends to make equipotential lines convex toward channel exit and is even parallel to the wall surface in the near-wall region. Further investigation predicts that the combination of high emissive dielectric wall and segmented low-emissive dielectric wall is a promising way to reduce plume divergence (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Pilot instrumentation of a Superpave test section at the Kansas Accelerated Testing laboratory

    Science.gov (United States)

    2003-04-01

    Two Superpave test sections were constructed at the Kansas Accelerated Testing Laboratory (K-ATL) with 12.5 mm (2 in) nominal maximum size Superpave mixture (SM-2A) with varying percentages (15 and 30 percent) of river sand. A 150 kN (34 kip) tandem ...

  13. The Other Hall Effect: College Board Physics

    Science.gov (United States)

    Sheppard, Keith; Gunning, Amanda M.

    2013-01-01

    Edwin Herbert Hall (1855-1938), discoverer of the Hall effect, was one of the first winners of the AAPT Oersted Medal for his contributions to the teaching of physics. While Hall's role in establishing laboratory work in high schools is widely acknowledged, his position as chair of the physics section of the Committee on College Entrance…

  14. Diagnostics Systems for Permanent Hall Thrusters Development

    Science.gov (United States)

    Ferreira, Jose Leonardo; Soares Ferreira, Ivan; Santos, Jean; Miranda, Rodrigo; Possa, M. Gabriela

    This work describes the development of Permanent Magnet Hall Effect Plasma Thruster (PHALL) and its diagnostic systems at The Plasma Physics Laboratory of University of Brasilia. The project consists on the construction and characterization of plasma propulsion engines based on the Hall Effect. Electric thrusters have been employed in over 220 successful space missions. Two types stand out: the Hall-Effect Thruster (HET) and the Gridded Ion Engine (GIE). The first, which we deal with in this project, has the advantage of greater simplicity of operation, a smaller weight for the propulsion subsystem and a longer shelf life. It can operate in two configurations: magnetic layer and anode layer, the difference between the two lying in the positioning of the anode inside the plasma channel. A Hall-Effect Thruster-HET is a type of plasma thruster in which the propellant gas is ionized and accelerated by a magneto hydrodynamic effect combined with electrostatic ion acceleration. So the essential operating principle of the HET is that it uses a J x B force and an electrostatic potential to accelerate ions up to high speeds. In a HET, the attractive negative charge is provided by electrons at the open end of the Thruster instead of a grid, as in the case of the electrostatic ion thrusters. A strong radial magnetic field is used to hold the electrons in place, with the combination of the magnetic field and the electrostatic potential force generating a fast circulating electron current, the Hall current, around the axis of the Thruster, mainly composed by drifting electrons in an ion plasma background. Only a slow axial drift towards the anode occurs. The main attractive features of the Hall-Effect Thruster are its simple design and operating principles. Most of the Hall-Effect Thrusters use electromagnet coils to produce the main magnetic field responsible for plasma generation and acceleration. In this paper we present a different new concept, a Permanent Magnet Hall

  15. Annual report 1991 of Munich University and Technical University Accelerator Laboratory

    International Nuclear Information System (INIS)

    1992-01-01

    The experimental work in the Accelerator Laboratory contains investigations of nuclear reactions and nuclear structure, studies of atom physics and the application of nuclear physics methods in physics and in interdisciplinary research. These applications are acceleration mass spectrometry to detect traces of radio-isotopes and material analysis with particle beams. The development of apparatus in the fields of accelereator construction, ion sources and targets are at the heart of the laboratory and help to establish its reputation. They are of the greatest importance for the education of students. The development stage for the superconducting post-accelerator TRITRON is complete and prototypes of the magnets and resonators were successfully tested and operated. The mass-production of all the components is under way or already finished. The standard injector for the tandem axxelerator and an injector for accelerator mass spectroscopy with stable isotopes are being newly designed. The experimental work is supplemented by the calculations of our theoretical collagues of core reaction mechanisms, core de-excitation and the Cerenkov radiation of core structures and transition strengths, by relativistic Hartree-Fock calculations and by star model calculations. (orig.) [de

  16. Anode sheath in Hall thrusters

    International Nuclear Information System (INIS)

    Dorf, L.; Semenov, V.; Raitses, Y.

    2003-01-01

    A set of hydrodynamic equations is used to describe quasineutral plasma in ionization and acceleration regions of a Hall thruster. The electron distribution function and Poisson equation are invoked for description of a near-anode region. Numerical solutions suggest that steady-state operation of a Hall thruster can be achieved at different anode sheath regimes. It is shown that the anode sheath depends on the thruster operating conditions, namely the discharge voltage and the mass flow rate

  17. Optimization of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fisch, Nathaniel J.

    2007-01-01

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.

  18. Optimization of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fi, Nathaniel J.

    2007-01-01

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation

  19. Current sheets in the Earth’s magnetosphere and in laboratory experiments: The magnetic field structure and the Hall effect

    International Nuclear Information System (INIS)

    Frank, A. G.; Artemyev, A. V.; Zelenyi, L. M.

    2016-01-01

    The main characteristics of current sheets (CSs) formed in laboratory experiments are compared with the results of satellite observations of CSs in the Earth’s magnetotail. We show that many significant features of the magnetic field structure and the distributions of plasma parameters in laboratory and magnetospheric CSs exhibit a qualitative similarity, despite the enormous differences of scales, absolute values of plasma parameters, magnetic fields, and currents. In addition to a qualitative comparison, we give a number of dimensionless parameters that demonstrate the possibility of laboratory modeling of the processes occurring in the magnetosphere.

  20. Testing and interfacing intelligent power supplies for the Los Alamos National Laboratory Accelerator Complex

    International Nuclear Information System (INIS)

    Sturrock, J.C.; Cohen, S.; Weintraub, B.L.; Hayden, D.J.; Archuleta, S.F.

    1992-01-01

    New high-current, high-precision microprocessor-controlled power supplies, built by Alpha Scientific Electronics of Hayward, CA, have been installed at the Los Alamos National Laboratory Accelerator Complex. Each unit has sophisticated microprocessor control on-board and communicates via RS-422 (serial communications). The units use a high level ASCII-based control protocol. Performance tests were conducted to verify adherence to specification and to ascertain ultimate long-term stability. The ''front-end'' software used by the accelerator control system has been written to accommodate these new devices. The supplies are interfaced to the control system through a terminal server port connected to the site-wide ediernet backbone. Test design and results as well as details of the software implementation for the analog and digital control of the supplies through the accelerator control system are presented

  1. Accelerator laboratories: development centers for experimental physics and technology in Mexico

    International Nuclear Information System (INIS)

    Mazari, M.

    1989-01-01

    Three years ago in this Nuclear Center the author and Professor Graef expounded the inception and development of experimental physics and new techniques centered about laboratories and equipped in our country with positive ion accelerators. Extracted here is the information on the laboratories that have allowed professional training as well as the furtherance of scientific productivity in each group. An additional proposal as to how the technical groups knowledgeable in advanced technology might contribute significantly to adequate preparation of youth at the intermediate level able to generate innocuous micro industries in their own neighbourhood. (Author). 5 refs, 2 figs, 2 tabs

  2. An aerial radiological survey of the Fermi National Accelerator Laboratory and surrounding area, Batavia, Illinois

    International Nuclear Information System (INIS)

    Fritzsche, A.E.

    1990-11-01

    An aerial radiological gamma survey was conducted over the Fermi National Accelerator Laboratory during 1 through 6 June 1989. Flight lines at 150-foot altitude and 250-foot line spacings assured nearly 100% coverage. The terrestrial exposure at about 6 μR/h was nearly the same as that measured by the previous survey of this area (May 1977). Ten anomalous areas, mostly Na-22 and Mn-54, were detected within buildings and laboratories in the area. Although these locations have changed somewhat from the 1977 survey, the aerial data shows good agreement with the ground-based ion chamber and soil sample data. 7 refs., 15 figs., 1 tab

  3. PIG's Speed Estimated with Pressure Transducers and Hall Effect Sensor: An Industrial Application of Sensors to Validate a Testing Laboratory.

    Science.gov (United States)

    Lima, Gustavo F; Freitas, Victor C G; Araújo, Renan P; Maitelli, André L; Salazar, Andrés O

    2017-09-15

    The pipeline inspection using a device called Pipeline Inspection Gauge (PIG) is safe and reliable when the PIG is at low speeds during inspection. We built a Testing Laboratory, containing a testing loop and supervisory system to study speed control techniques for PIGs. The objective of this work is to present and validate the Testing Laboratory, which will allow development of a speed controller for PIGs and solve an existing problem in the oil industry. The experimental methodology used throughout the project is also presented. We installed pressure transducers on pipeline outer walls to detect the PIG's movement and, with data from supervisory, calculated an average speed of 0.43 m/s. At the same time, the electronic board inside the PIG received data from odometer and calculated an average speed of 0.45 m/s. We found an error of 4.44%, which is experimentally acceptable. The results showed that it is possible to successfully build a Testing Laboratory to detect the PIG's passage and estimate its speed. The validation of the Testing Laboratory using data from the odometer and its auxiliary electronic was very successful. Lastly, we hope to develop more research in the oil industry area using this Testing Laboratory.

  4. Essay of accelerator R and D in a small laboratory of a university. Prototype of IHQ linac 1985-1989

    International Nuclear Information System (INIS)

    Hattori, Toshiyuki

    2004-01-01

    This is a series of stories on developing particle accelerators employing new acceleration principles at a university laboratory. In this paper the design, the cold-model test, the fabrication and the acceleration test of a linear accelerator (linac) of 'IHQ' type are described. The word IHQ is coined by combining 'Inter-digital H' and 'Radio-Frequency Quadrupole', which are the words for types of linacs. The linac of IHQ type can accelerate particles with rather low injection energy and can perform a high acceleration efficiency. In the acceleration test, the proton beam from an RFQ linac with an energy of 0.8MeV was injected to the IHQ linac and accelerated up to 2 MeV as designed. The effective shunt impedance of the accelerator structure was measured to be as high as 132MΩ/m as expected. (K.Y.)

  5. Doubling Beam Intensity Unlocks Rare Opportunities for Discovery at Fermi National Accelerator Laboratory

    International Nuclear Information System (INIS)

    Segui, Jennifer A.

    2014-01-01

    Particle accelerators such as the Booster synchrotron at the Fermi National Accelerator Laboratory (FNAL) produce high-intensity proton beams for particle physics experiments that can ultimately reveal the secrets of the universe. High-intensity proton beams are required by experiments at the ''intensity frontier'' of particle physics research, where the availability of more particles improves the chances of observing extremely rare physical processes. In addition to their central role in particle physics experiments, particle accelerators have found widespread use in industrial, nuclear, environmental, and medical applications. RF cavities are essential components of particle accelerators that, depending on the design, can perform multiple functions, including bunching, focusing, decelerating, and accelerating a beam of charged particles. Engineers are working to model the RF cavities required for upgrading the 40-year old Booster synchrotron. It is a rather complicated process to refurbish, test, and qualify the upgraded RF cavities to sustain an increased repetition rate of the RF field required to produce proton beams at double the current intensity. Both multiphysics simulation and physical measurements are used to evaluate the RF, thermal, and mechanical properties of the Booster RF cavities.

  6. Preliminary Conceptual Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Mark [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-04-22

    Plasma wakefield acceleration has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider is the focus of FACET, a National User Facility at SLAC. The existing FACET National User Facility uses part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and positrons. FACET-II is a new test facility to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. It is the only facility in the world with high energy positron beams. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The design parameters for FACET-II are set by the requirements of the plasma wakefield experimental program. To drive the plasma wakefield requires a high peak current, in excess of 10kA. To reach this peak current, the electron and positron design bunch size is 10μ by 10μ transversely with a bunch length of 10μ. This is more than 200 times better than what has been achieved at the existing FACET. The beam energy is 10 GeV, set by the Linac length available and the repetition rate is up to 30 Hz. The FACET-II project is scheduled to be constructed in three major stages. Components of the project discussed in detail include the following: electron injector, bunch compressors and linac, the positron system, the Sector 20 sailboat and W chicanes

  7. The Dresden Felsenkeller shallow-underground accelerator laboratory for nuclear astrophysics - Status and first physics program

    Energy Technology Data Exchange (ETDEWEB)

    Ilgner, Ch. [Nuclear Astrophysics group, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden (Germany)

    2015-07-01

    Favored by the low background in underground laboratories, low-background accelerator-based experiments are an important tool to study nuclear reactions involving stable charged particles. This technique has been used for many years with great success at the 0.4 MV LUNA accelerator in the Gran Sasso laboratory in Italy, protected from cosmic rays by 1400 m of rock. However, the nuclear reactions of helium and carbon burning and the neutron source reactions for the astrophysical s-process require higher beam energies than those available at LUNA. Also the study of solar fusion reactions necessitates new data at higher energies. As a result, in the present NuPECC long range plan for nuclear physics in Europe, the installation of one or more higher-energy underground accelerators is strongly recommended. An intercomparison exercise using the same High-Purity Ge detector at several sites has shown that, with a combination of 45 m rock overburden, as can be found in the Felsenkeller underground site in Dresden, and an active veto against the remaining muon flux, in a typical nuclear astrophysics setup a background level can be achieved that is similar to the deep underground scenario as in the Gran- Sasso underground laboratory, for instance. Recently, a muon background study and geodetic measurements were carried out by the REGARD group. It was estimated that the rock overburden at the place of the future ion accelerator is equivalent to 130 m of water. The maximum muon flux measured was 2.5 m{sup -2} sr{sup -1} s{sup -1}, in the direction of the tunnel entrance. Based on this finding, a used 5 MV pelletron tandem accelerator with 250 μA up-charge current and external sputter ion source has been obtained and transported to Dresden. Work on an additional radio-frequency ion source on the high voltage terminal is in progress and far advanced. The installation of the accelerator in the Felsenkeller is expected for the near future. The status of the project and the

  8. Acceleration to failure in geophysical signals prior to laboratory rock failure and volcanic eruptions (Invited)

    Science.gov (United States)

    Main, I. G.; Bell, A. F.; Greenhough, J.; Heap, M. J.; Meredith, P. G.

    2010-12-01

    The nucleation processes that ultimately lead to earthquakes, volcanic eruptions, rock bursts in mines, and landslides from cliff slopes are likely to be controlled at some scale by brittle failure of the Earth’s crust. In laboratory brittle deformation experiments geophysical signals commonly exhibit an accelerating trend prior to dynamic failure. Similar signals have been observed prior to volcanic eruptions, including volcano-tectonic earthquake event and moment release rates. Despite a large amount of effort in the search, no such statistically robust systematic trend is found prior to natural earthquakes. Here we describe the results of a suite of laboratory tests on Mount Etna Basalt and other rocks to examine the nature of the non-linear scaling from laboratory to field conditions, notably using laboratory ‘creep’ tests to reduce the boundary strain rate to conditions more similar to those in the field. Seismic event rate, seismic moment release rate and rate of porosity change show a classic ‘bathtub’ graph that can be derived from a simple damage model based on separate transient and accelerating sub-critical crack growth mechanisms, resulting from separate processes of negative and positive feedback in the population dynamics. The signals exhibit clear precursors based on formal statistical model tests using maximum likelihood techniques with Poisson errors. After correcting for the finite loading time of the signal, the results show a transient creep rate that decays as a classic Omori law for earthquake aftershocks, and remarkably with an exponent near unity, as commonly observed for natural earthquake sequences. The accelerating trend follows an inverse power law when fitted in retrospect, i.e. with prior knowledge of the failure time. In contrast the strain measured on the sample boundary shows a less obvious but still accelerating signal that is often absent altogether in natural strain data prior to volcanic eruptions. To test the

  9. Establishment of nuclear data system - Feasibility study for neutron-beam= facility at pohang accelerator laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Nam Kung, Won; Koh, In Soo; Cho, Moo Hyun; Kim, Kui Nyun; Kwang, Hung Sik; Park, Sung Joo [Pohang Accelerator Laboratory, Pohang (Korea, Republic of)

    1996-12-01

    Nuclear data which have been produced by a few developed countries in the= past are essential elements to many disciplines, especially to nuclear engineering. As we promote our nuclear industry further to the level of advanced countries, we also have to establish the Nuclear Data System to produce and evaluate nuclear data independently. We have studied the possibility to build a neutron-beam facility utilizing accelerator facilities, technologies and man powers at pohang Accelerator Laboratory. We found specific parameters for the PAL 100-MeV electron linac based on the existing klystron, modulator, accelerating tubes and other facilities in the PAL; the beam energy is 60-100 MeV, the beam current for the short pulse (10 ns) is 2 A and for the long pulse is 500 mA and the pulse repetition rate is 60 Hz. We propose a neutron-beam facility using PAL 100-MeV electron linac where we can use a Ta-target for the neutron generation and three different time-of-flight beam lines (10 m, 20 m, and 100 m). One may find that the proposed neutron-beam facility is comparable with other operating neutron facilities in the world. We conclude that the proposed neutron-beam facility utilizing the existing accelerator facility in the PAL would be an excellent facility for neutron data production in combination with the ` Hanaro` facility in KAERI. 8 refs., 11 tabs., 12 figs. (author)

  10. An improved 8 GeV beam transport system for the Fermi National Accelerator Laboratory

    International Nuclear Information System (INIS)

    Syphers, M.J.

    1987-06-01

    A new 8 GeV beam transport system between the Booster and Main Ring synchrotrons at the Fermi National Accelerator Laboratory is presented. The system was developed in an effort to improve the transverse phase space area occupied by the proton beam upon injection into the Main Ring accelerator. Problems with the original system are described and general methods of beamline design are formulated. Errors in the transverse properties of a beamline at the injection point of the second synchrotron and their effects on the region in transverse phase space occupied by a beam of particles are discussed. Results from the commissioning phase of the project are presented as well as measurements of the degree of phase space dilution generated by the transfer of 8 GeV protons from the Booster synchrotron to the Main Ring synchrotron

  11. What's new with FASTBUS and what's it done in the particle accelerator laboratories

    International Nuclear Information System (INIS)

    Costrell, L.; Dawson, W.K.; Platner, E.D.; Paffrath, L.; Barsotti, E.J.; Downing, R.W.; Ikeda, H.; Nelson, R.O.; Kolpakov, I.; Gustavson, D.B.; Walz, H.W.

    1991-01-01

    The FASTBUS modular high-speed data acquisition and control system has been described in earlier papers. Implementations have since been made in accelerator laboratories world-wide resulting in clarifications, modifications and extensions. Of tremendous benefit to users have been FASTBUS Standard Routines. The availability of such standard software is unique for high speed bus systems and resulted from the involvement of hardware and software specialists in all aspects of the development. FASTBUS is the highest performance instrumentation and data acquisition bus in existence and its development was essential to handle the outputs of detectors used with high energy accelerators now in operation. It has been an important factor in recent experiments, including the Z 0 measurements at CERN, Fermilab and SLAC. Also among numerous FASTBUS implementations are those for TPC systems at KEK and BNL. 2 refs., 5 figs

  12. Development of a Charged Particle Microbeam for Single-Particle Subcellular Irradiations at the MIT Laboratory for Accelerator Beam Application

    International Nuclear Information System (INIS)

    Yanch, Jacquelyn C.

    2004-01-01

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube

  13. Key Performance Indicators to Measure Improvement After Implementation of Total Laboratory Automation Abbott Accelerator a3600.

    Science.gov (United States)

    Miler, Marijana; Nikolac Gabaj, Nora; Dukic, Lora; Simundic, Ana-Maria

    2017-12-27

    The aim of the study was to estimate improvement of work efficiency in the laboratory after implementation of total laboratory automation (TLA) by Abbott Accelerator a3600 in the laboratory with measuring different key performance indicators (KPIs) before and after TLA implementation. The objective was also to recommend steps for defining KPIs in other laboratories. For evaluation of improvement 10 organizational and/or technical KPIs were defined for all phases of laboratory work and measured before (November 2013) and after (from 2015 to 2017) TLA implementation. Out of 10 defined KPIs, 9 were successfully measured and significantly improved. Waiting time for registration of samples in the LIS was significantly reduced from 16 (9-28) to 9 (6-16) minutes after TLA (P performed at core biochemistry analyzers which significantly reduced walking distance for sample management (for more than 800 m per worker) and number of tube touches (for almost 50%). Analyzers downtime and engagement time for analyzers maintenance was reduced for 50 h and 28 h per month, respectively. TLA eliminated manual dilution of samples with extreme results with sigma values increment from 3.4 to >6 after TLA. Although median turnaround time TAT for potassium and troponin was higher (for approximately 20 min), number of outliers with TAT >60 min expressed as sigma values were satisfying (>3). Implementation of the TLA improved the most of the processes in our laboratory with 9 out of 10 properly defined and measured KPIs. With proper planning and defining of KPIs, every laboratory could measure changes in daily workflow.

  14. The ISOLDE hall

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Since 1992, after its move from the 600 MeV SC, ISOLDE is a customer of the Booster (then 1 GeV, now 1.4 GeV). The intense Booster beam (some 3E13 protons per pulse) is directed onto a target, from which a mixture of isotopes emanates. After ionization and electrostatic acceleration to 60 keV, they enter one of the 2 spectrometers (General Purpose Separator: GPS, and High Resolution Separator: HRS) from which the selected ions are directed to the experiments. The photos show: the REX-ISOLDE post accelerator; the mini-ball experiment; an overview of the ISOLDE hall. In the picture (_12) of the hall, the separators are behind the wall. From either of them, beams can be directed into any of the many beamlines towards the experiments, some of which are visible in the foreground. The elevated cubicle at the left is EBIS (Electron Beam Ion Source), which acts as a charge-state multiplier for the REX facility. The ions are further mass analzyzed and passed on to the linac which accelerates them to higher energies. T...

  15. Synchrotron radiation laboratories at the Bonn electron accelerators. a status report

    Science.gov (United States)

    Hormes, J.

    1987-07-01

    At the Physikalisches Institut of the University in Bonn experiments with synchrotron radiation were carried out ever since 1962. At the moment (June 1986) all work takes place in the SR-laboratory at the 2.5 GeV synchrotron. A 3.5 GeV stretcher ring (ELSA) is under construction and will come into operation at the end of 1986. This accelerator will also run as a storage ring for synchrotron radiation experiments and a laboratory to be used at this machine is also under consideration. The SR experiments which are carried out in Bonn try to take advantage of the fact that we are still using a high energy synchrotron for our work. Besides basic research also applied work is done using synchrotron radiation even as a production tool for X-ray lithography.

  16. A system for pulse Hall effect measurements

    International Nuclear Information System (INIS)

    Orzechowski, T.; Kupczak, R.

    1975-01-01

    Measuring system for fast Hall-voltage changes in an n-type germanium sample irradiated at liquid nitrogen temperature with a high-energy electron-beam from the Van de Graaff accelerator is described. (author)

  17. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K., E-mail: lrk@slac.stanford.edu; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); and others

    2015-07-15

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  18. The future of producing separated stable isotopes at Oak Ridge National Laboratory for accelerator applications

    International Nuclear Information System (INIS)

    Collins, E.D.

    1994-01-01

    Separated stable isotopes, produced in the calutrons at Oak Ridge National Laboratory, are essential target materials for production of numerous radioisotopes in accelerators and reactors. Recently, separated stable isotope production has been curtailed because government appropriations were discontinued and salts revenues decreased. The calutrons were placed in standby and the operating staff reduced to enable support by sales from existing inventories. Appeals were made to industry and government to preserve this national capability. Methods for providing volume-based price reductions were created to attract support from commercial isotope users. In 1994, the Department of Energy's Isotope Production and Distribution Program was restructured and a strategy produced to seek appropriated funding for the future production of rare, nonprofitable isotopes for research uses. This strategy, together with new demands for medical isotopes, will enable future operation of the calutrons. Moreover, production may be enhanced by complementing calutron capabilities with the Plasma Separation Process

  19. Design Study of Low-Emittance Injector for SASE-XFEL at Pohang Accelerator Laboratory

    CERN Document Server

    Park, Sungju J; Yun, H J; Kim, D E; Kim, E S; Ko, In Soo; Nam, S H; Oh, Jong Seok

    2004-01-01

    We report on the design study of the low-emittance injector for the SASE-XFEL that is being considered as a possible choice for the next-generation light sources at the Pohang Accelerator Laboratory, POSTECH. Using the PARMELA code, beam dynamics simulations were performed aiming to achieve the invariant-envelope matching at booster entrance, and to insure beam emittance < 1 mm.mrad (at 1-nC bunch charge) at the injector end. We also utilized the MAGIC code for analyzing beam dynamics inside the RF-gun cavities and to confirm the part of PARMELA simulations. Hardware design was done with possible implementation of high-Q.E. photocathode, which could reduce burdens imposed on laser system, thus improving overall system stability and reliability.

  20. Annual Site Environmental Report: 2015 (ASER) for the SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sabba, Dellilah [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-09-01

    This report, prepared by the SLAC National Accelerator Laboratory (SLAC) for the U.S. Department of Energy (DOE), SLAC Site Office (SSO), provides a comprehensive summary of the environmental program activities at SLAC for calendar year 2015. Annual Site Environmental Reports (ASERs) are prepared for all DOE sites with significant environmental activities, and distributed to relevant external regulatory agencies and other interested organizations or individuals. To the best of my knowledge, this report accurately summarizes the results of the 2015 environmental monitoring, compliance, and restoration programs at SLAC. This assurance can be made based on SSO and SLAC review of the ASER, and quality assurance protocols applied to monitoring and data analyses at SLAC.

  1. Upgrading the control system for the Accelerators at the Svedberg Laboratory

    International Nuclear Information System (INIS)

    Gajewski, K.J.; Thuresson, L.; Johansson, O.

    1992-01-01

    Two accelerators at The Svedberg Laboratory in Uppsala, the Gustaf Werner cyclotron and the CELSIUS ring, will get a new control system. At present both the cyclotron and the ring have their own control systems based on S99 and PDP-11 minicomputers respectively. There are also a number of subsystems which are controlled separately from the stand-alone PC based consoles (ECR ion source, electron cooler, vacuum system). The goal of the rejuvenation is to integrate all existing control systems and provide the new system with an uniform operators interface based on workstations. The obsolete S99 microcomputers will be substituted with a VME system and all subsystems will be connected to the Ethernet. The upgrade strategy enabling the transformation of the system without any long shut-down period is discussed. Hardware and software planned for the upgrade is presented together with a discussion of expected problems. (author)

  2. Laboratory studies of magnetized collisionless flows and shocks using accelerated plasmoids

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2015-11-01

    Magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those found in both space and astrophysical shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to high velocities (100s of km/s); resulting in β ~ 1, collisionless plasma flows with sonic and Alfvén Mach numbers of ~10. The FRC subsequently impacts a static target such as a strong parallel or anti-parallel (reconnection-wise) magnetic mirror, a solid obstacle, or neutral gas cloud to create shocks with characteristic length and time scales that are both large enough to observe yet small enough to fit within the experiment. This enables study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental capabilities of MSX will be presented, including diagnostics, selected recent results, and future directions. Supported by the DOE Office of Fusion Energy Sciences under contract DE-AC52-06NA25369.

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

    International Nuclear Information System (INIS)

    Deken, J.

    2009-01-01

    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.

  4. Accelerators

    CERN Multimedia

    CERN. Geneva

    2001-01-01

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

  5. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.

    1976-01-01

    A brief discussion is given of: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti p p, and other options; (3) hall for the lepton detector; and, (4) hall for the hadron spectrometer

  6. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.

    1976-01-01

    On May 26 and 27, 1976, approximately 50 people met for an informal workshop on plans for experimental halls for ISABELLE. Plans as they exist in the May 1976 version of the ISABELLE proposal were presented. Discussions were held on the following four general topics by separate working groups: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti pp, and other options; (3) hall for the lepton detector; and (4) hall for the hadron spectrometer. The planning for experimental halls at PEP, the hall for the lepton detector, the hadron spectrometer, and open areas are discussed

  7. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.

    1976-01-01

    At the experimental halls workshop, discussions were held on: (1) open areas as compared with enclosed halls; (2) the needs of ep, anti pp, and other options; (3) the hall for the lepton detector; and (4) the hall for the hadron spectrometer. The value of different possibilities for the future experimental program was explored. A number of suggestions emerged which will be used as the design of the experimental halls progresses

  8. 2 March 2012 - US Google Management Team Executive Chairman E. Schmidt visiting the LHC superconducting magnet test hall with Director for Accelerators and Technology S. Myers and Head of Technology Department F. Bordry; signing the guest book with CERN Director-General R. Heuer.

    CERN Multimedia

    Maximilien Brice

    2012-01-01

    2 March 2012 - US Google Management Team Executive Chairman E. Schmidt visiting the LHC superconducting magnet test hall with Director for Accelerators and Technology S. Myers and Head of Technology Department F. Bordry; signing the guest book with CERN Director-General R. Heuer.

  9. Resistive Instabilities in Hall Current Plasma Discharge

    International Nuclear Information System (INIS)

    Litvak, Andrei A.; Fisch, Nathaniel J.

    2000-01-01

    Plasma perturbations in the acceleration channel of a Hall thruster are found to be unstable in the presence of collisions. Both electrostatic lower-hybrid waves and electromagnetic Alfven waves transverse to the applied electric and magnetic field are found to be unstable due to collisions in the E X B electron flow. These results are obtained assuming a two-fluid hydrodynamic model in slab geometry. The characteristic frequencies of these modes are consistent with experimental observations in Hall current plasma thrusters

  10. Linear induction accelerators at the Los Alamos National Laboratory DARHT facility

    International Nuclear Information System (INIS)

    Nath, Subrata

    2010-01-01

    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 slicing micro-pulses out of a longer ∼1.6-microseconds (flat-top) pulse of nominal beam-energy and -current of 17 MeV and 2 kA respectively. Bremsstrahlung x-rays, shining on a hydro-dynamical experimental device, are produced by focusing the electron beam-pulses onto a high-Z target. Variable pulse-formats allow for adjustment of the pulse-to-pulse doses to record a time sequence of x-ray images of the explosively driven imploding mock device. Herein, we present a sampling of the numerous physics and engineering aspects along with the current status of the fully operational dual axes capability. First successful simultaneous use of both the axes for a hydrodynamic experiment was achieved in 2009.

  11. Coating and Interface Degradation of Coated steel, Part 2: Accelerated Laboratory Tests

    International Nuclear Information System (INIS)

    Cambier, S.M.; Frankel, G.S.

    2014-01-01

    In a previous paper, it was demonstrated that the measurement of cathodic delamination by the Scanning Kelvin Probe can assess the interface stability of poly(vinyl butyral) (PVB) coated steel after field exposure. This technique was utilized to characterize the degradation of the polymer/metal interface in several outdoor climates. In this paper, the effects of environmental factors on the interface degradation were investigated in the laboratory. The mechanisms measured in the field were reproduced to provide input in the development of an appropriate accelerated test for PVB coated steel. The ASTM B117 and G154 standardized tests were investigated individually and sequentially. The interface stability improved after 24 h of ASTM G154 exposure. After 144 h of exposure to ASTM G154 exposure, polymer oxidation took place simultaneously with interface degradation. The condensation phase of the ASTM G154 test was responsible for the interface improvement while the ultraviolet radiation triggered the interface degradation. Pre-exposure to ASTM G154 delayed wet de-adhesion during ASTM B117 exposure. After wet de-adhesion caused by 6 h of ASTM B117, exposure to ASTM G154 for 24 h increased the interface stability. The effects of ultraviolet radiation, relative humidity, temperature and environment on interface degradation were investigated in a special chamber. Humidity was the primary factor found to influence the interface improvement during G154 exposure. A wet/dry salt fog cycle with irradiation by an ultraviolet or filtered xenon arc lamp around room temperature was suggested to reproduce the competition between the interface improvement and the interface degradation that takes place in the field

  12. Vacuum system of Synchrotron Light National Laboratory (LNLS) linear accelerator: project and results

    International Nuclear Information System (INIS)

    Rocha, L.R.B.; Gomes, P.A.P.

    1990-01-01

    The LINAC, electron linear accelerator used as injector for storage ring in production of synchrotron radiation at Laboratorio Nacional de Luz Sincrotron (LNLS) is described. The LINAC basic parameters, the dimension calculations of vacuum system and the final project with all components are presented. The vacuum system for electron gun tests and accelerator structure tests is described. (M.C.K.)

  13. Student Teachers' Modeling of Acceleration Using a Video-Based Laboratory in Physics Education: A Multimodal Case Study

    Directory of Open Access Journals (Sweden)

    Louis Trudel

    2016-06-01

    Full Text Available This exploratory study intends to model kinematics learning of a pair of student teachers when exposed to prescribed teaching strategies in a video-based laboratory. Two student teachers were chosen from the Francophone B.Ed. program of the Faculty of Education of a Canadian university. The study method consisted of having the participants interact with a video-based laboratory to complete two activities for learning properties of acceleration in rectilinear motion. Time limits were placed on the learning activities during which the researcher collected detailed multimodal information from the student teachers' answers to questions, the graphs they produced from experimental data, and the videos taken during the learning sessions. As a result, we describe the learning approach each one followed, the evidence of conceptual change and the difficulties they face in tackling various aspects of the accelerated motion. We then specify advantages and limits of our research and propose recommendations for further study.

  14. Quantum Hall effect

    International Nuclear Information System (INIS)

    Joynt, R.J.

    1982-01-01

    A general investigation of the electronic structure of two dimensional systems is undertaken with a view towards understanding the quantum Hall effect. The work is limited to the case of a strong perpendicular magnetic field, with a disordered potential and an externally applied electric field. The electrons are treated as noninteracting. First, the scattering theory of the system is worked out. The surprising result is found that a wavepacket will reform after scattering from an isolated potential. Also it will tend to be accelerated in the neighborhood of the scatterer if the potential has bound states. Fredholm theory can then be used to show that the extended states carry an additional current which compensates for the zero current of the bound states. Together, these give the quantized conductance. The complementary case of a smooth random potential is treated by a path-integral approach which exploits the analogies to the classical equations of motion. The Green's function can be calculated approximately, which gives the general character of both the bound and extended states. Also the ratio of these two types of states can be computed for a given potential. The charge density is uniform in first approximation, and the Hall conductance is quantized. Higher-order corrections for more rapidly fluctuating potential are calculated. The most general conditions under which the conductance is quantized are discussed. Because of the peculiar scattering properties of the system, numerical solution of the Schroedinger equation is of interest, both to confirm the analytical results, and for pedagogical reasons. The stability and convergence problems inherent in the computer solution of the problem are analyzed. Results for some model scattering potentials are presented

  15. Experience with copper oxide production in antiproton source components at Fermi National Accelerator Laboratory

    International Nuclear Information System (INIS)

    Ader, Christine R.; Harms, Elvin R. Jr; Morgan, James P.

    2000-01-01

    The Antiproton (Pbar) Source at Fermi National Accelerator Laboratory is a facility comprised of a target station, two rings called the Debuncher and Accumulator and the transport lines between those rings and the remainder of the particle accelerator complex. Water is by far the most common medium for carrying excess heat away from components, primarily electromagnets, in this facility. The largest of the water systems found in Pbar is the 95 degree Fahrenheit Low Conductivity Water (LCW) system. LCW is water which has had free ions removed, increasing its resistance to electrical current. This water circuit is used to cool magnets, power supplies, and stochastic cooling components and typically has a resistivity of 11--18 megaohms-cm. For more than ten years the Antiproton rings were plagued with overheating magnets due to plugged water-cooling channels. Various repairs have been tried over the years with no permanent success. Throughout all of this time, water samples have indicated copper oxide, CuO, as the source of the contamination. Matters came to a head in early 1997 following a major underground LCW leak between the Central Utilities Building and the Antiproton Rings enclosures. Over a span of several weeks following system turn-on, some twenty magnets overheated leading to unreliable Pbar source operation. Although it was known that oxygen in the system reacts with the copper tubing to form CuO, work to remedy this problem was not undertaken until this time period. Leaks, large quantities of make-up water, infrequent filter replacement, and thermal cycling also result in an increase in the corrosion product release rate. A three-pronged approach has been implemented to minimize the amount of copper oxide available to plug the magnets: (1) installation of an oxygen removal system capable of achieving dissolved oxygen concentrations in the parts per billion (ppb) range; (2) regular closed-loop filter/flushing of the copper headers and magnets and stainless

  16. Implementation of an electronic laboratory notebook to accelerate data review in bioanalysis.

    Science.gov (United States)

    Shoup, Ronald E; Beato, Brian D; Pisek, April; White, Jessica; Branstrator, Laurel; Bousum, Abby; Roach, Jasmine; Grever, Tim

    2013-07-01

    Electronic laboratory notebooks increase opportunities for collaboration and information exchange when compared with paper records. Depending on the degree of implementation, a laboratory- or enterprise-wide system can unify the collection, review and dissemination of data to improve laboratory efficiency and productivity. The advantages of an electronic laboratory notebook for speeding data review in bioanalysis are discussed, through the use of validated templates and organizational constructs to block errors in real-time and reduce manual audit tasks.

  17. Progress Towards a Laboratory Test of Alfvénic Electron Acceleration

    Science.gov (United States)

    Schroeder, J. W. R.; Skiff, F.; Howes, G. G.; Kletzing, C. A.; Carter, T. A.; Vincena, S.; Dorfman, S.

    2016-10-01

    Alfvén waves are thought to be a key mechanism for accelerating auroral electrons. Due to inherent limitations of single point measurements, in situ data has been unable to demonstrate a causal relationship between Alfvén waves and accelerated electrons. Electron acceleration occurs in the inner magnetosphere where the Alfvén speed is greater than the electron thermal speed. In these conditions, Alfvén waves can have an electric field aligned with the background magnetic field B0 if the scale of wave structure across B0 is comparable to the electron skin depth. In the Large Plasma Device (LaPD), Alfvén waves are launched in conditions relevant to the inner magnetosphere. The reduced parallel electron distribution function is measured using a whistler-mode wave absorption diagnostic. The linear electron response has been measured as oscillations of the electron distribution function at the Alfvén wave frequency. These measurements agree with linear theory. Current efforts focus on measuring the nonlinear acceleration of electrons that is relevant to auroral generation. We report on recent progress including experiments with a new higher-power Alfvén wave antenna with the goal of measuring nonlinear electron acceleration. This work was supported by the NSF GRFP and by Grants from NSF, DOE, and NASA. Experiments were performed at the Basic Plasma Science Facility which is funded by DOE and NSF.

  18. Laboratory investigation of physical mechanisms of auroral charged particle acceleration in the field-aligned currents layers

    Science.gov (United States)

    Gavrilov, B.; Zetzer, J.; Sobyanin, D.; Podgorny, I.

    One of the major topics of space weather research is to understand auroral structure and the processes that guide, accelerate, and otherwise control particle precipitation and produce auroral substorms. Navigation, communications and radars in the high latitude regions are severely affected through the effects on the ionosphere. It has long been recognized that the direct cause of the aurora is the precipitation of energetic electrons and ions into the atmosphere leading to excitation of the ambient atmospheric gases. Observations of the ionospheric ionization profiles and auroral precipitation characteristics have shown that field-aligned potential drops are formed to create this effect. The problem is that it is not clear the structure of the regions of magnetic field-aligned electric fields and how they are supported in the magnetospheric plasma. The objective of this research is to study the physical mechanisms of these phenomena in a laboratory experiment. It should be achieved by simulating the charged particle acceleration due to field-aligned electrical field generation in all totality of the interconnected events: generation of a plasma flow, its evolution in the magnetic field, polarization of plasma, generation of the field-aligned currents, development of instabilities in the plasma and current layers, double layers or anomalous resistance regions appearance, electrons acceleration. Parameters of the laboratory simulation and preliminary results of the experiment are discussed.

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

    Science.gov (United States)

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

    2015-04-01

    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 1.18 mm 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 μm). 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Cryogenic microsize Hall sensors

    International Nuclear Information System (INIS)

    Kvitkovic, J.; Polak, M.

    1993-01-01

    Hall sensors have a variety of applications in magnetic field measurements. The active area of the Hall sensor does not play an important role in measuring of homogeneous magnetic field. Actually Hall sensors are widely used to measure profiles of magnetic fields produced by magnetization currents in samples of HTC superconductors, as well as of LTC ones. Similar techniques are used to measure magnetization of both HTC and LTC superconductors. In these cases Hall sensor operates in highly inhomogeneous magnetic fields. Because of that, Hall sensors with very small active area are required. We developed and tested Hall sensors with active area 100 μm x 100 μm - type M and 50 μm x 50 μm - type V. Here we report on the most imporant parameters of these units, as well as on their properties as differential magnetometer. (orig.)

  1. Temperature Gradient in Hall Thrusters

    International Nuclear Information System (INIS)

    Staack, D.; Raitses, Y.; Fisch, N.J.

    2003-01-01

    Plasma potentials and electron temperatures were deduced from emissive and cold floating probe measurements in a 2 kW Hall thruster, operated in the discharge voltage range of 200-400 V. An almost linear dependence of the electron temperature on the plasma potential was observed in the acceleration region of the thruster both inside and outside the thruster. This result calls into question whether secondary electron emission from the ceramic channel walls plays a significant role in electron energy balance. The proportionality factor between the axial electron temperature gradient and the electric field is significantly smaller than might be expected by models employing Ohmic heating of electrons

  2. Skyrmions and Hall viscosity

    Science.gov (United States)

    Kim, Bom Soo

    2018-05-01

    We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physical quantities based on symmetries and have been previously applied to quantum Hall systems.

  3. Precast concrete elements for accelerated bridge construction : laboratory testing of precast substructure components, Boone County bridge.

    Science.gov (United States)

    2009-01-01

    Vol. 1-1: In July 2006, construction began on an accelerated bridge project in Boone County, Iowa that was composed of precast substructure : elements and an innovative, precast deck panel system. The superstructure system consisted of full-depth dec...

  4. Corrosion Screening of EV31A Magnesium and Other Magnesium Alloys using Laboratory-Based Accelerated Corrosion and Electro-Chemical Methods

    Science.gov (United States)

    2014-07-01

    Spray. Journal of Failure Analysis and Prevention 2008, 8 (2), 164–175. 34. Aluminium Alloy 5083, Plate and Sheet; SAE-AMS-QQ-A-250/6S; SAE...Corrosion Screening of EV31A Magnesium and Other Magnesium Alloys Using Laboratory-Based Accelerated Corrosion and Electro-chemical Methods...Magnesium and Other Magnesium Alloys Using Laboratory-Based Accelerated Corrosion and Electro-chemical Methods Brian E. Placzankis, Joseph P

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

    Science.gov (United States)

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

    2012-12-01

    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

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

    Science.gov (United States)

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

    2012-01-01

    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.

  7. Laboratory Testing of Precast Bridge Beck Panel Transverse Connections for Use in Accelerated Bridge Construction

    OpenAIRE

    Porter, Scott D.

    2009-01-01

    Precast concrete bridge deck panels have been used for decades to accelerate bridge construction. Cracking of the transverse connection between panels is a common problem that can damage deck overlays and cause connection leaking leading to corrosion of lower bridge elements. To better understand the behavior of bridge deck transverse female-to-female connections, shear and moment lab testing were performed at Utah State University for the Utah Department of Transportation. Two existing UDOT ...

  8. Experiments assigned to determine the acceleration of 8000kN shear laboratory model elements

    Science.gov (United States)

    Budiul Berghian, A.; Vasiu, T.; Abrudean, C.

    2017-01-01

    In this paper presents an experimental kinetics study by measuring accelerations using a bi-axial accelerometer constructed in the basis of a miniature integrated circuit, included in the class of micro-electrical and mechanical systems - MMA6261Q on the experimental installation reduced to the 1:5 dividing rule by comparison with the shear existent in exploitation, conceived and projected at the Faculty of Engineering in Hunedoara.

  9. Particle optics and accelerator modeling software for industrial and laboratory beamline design

    International Nuclear Information System (INIS)

    Gillespie, G.H.; Hill, B.W.

    1998-01-01

    The expanding variety of accelerator applications in research and industry places increased demands upon scientists and engineers involved in developing new accelerator and beamline designs. Computer codes for particle optics simulation have always played an important role in the design process and enhanced software tools offer the promise of improved productivity for beamline designers. This paper summarizes recent work on the development of advanced graphic user interface (GUI) software components, that can be linked directly to many of the standard particle optics programs used in the accelerator community, and which are aimed at turning that promise of improved productivity into a reality. An object oriented programming (OOP) approach has been adopted and a number of GUI components have been developed that run on several different operating systems. The emphasis is on assisting users in the setup and running of the optics programs without requiring any knowledge of the format, syntax, or similar requirements of the input. The components are being linked with several popular optics programs, including TRANSPORT, TURTLE, TRACE 3-D and PARMILA, to form integrated easy-to-use applications. Several advanced applications linking the GUI components with Lie algebra and other high-order simulation codes, as well as system level and facility modeling codes, are also under development. An overview of the work completed to date is presented, and examples of the new tools running on the Windows 95 operating system are illustrated. (orig.)

  10. Enhanced Performance of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Y.; Smirnov, A.; Fisch, N.J.

    2007-01-01

    The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50-60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma

  11. Deadline pressure and human error: a study of human failures on a particle accelerator at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Tiagha, E.A.

    1982-01-01

    The decline in industrial efficiency may be linked to decreased reliability of complex automatic systems. This decline threatens the viability of complex organizations in industrialized economies. Industrial engineering techniques that minimize system failure by increasing the reliability of systems hardware are well developed in comparison with those available to reduce human operator errors. The problem of system reliability and the associated costs of breakdown can be reduced if we understand how highly skilled technical personnel function in complex operations and systems. The purpose of this research is to investigate how human errors are affected by deadline pressures, technical communication and other socio-dynamic factors. Through the analysis of a technologically complex particle accelerator prototype at Brookhaven National Laboratory, two failure mechanisms: (1) physical defects in the production process and (2) human operator errors were identified. Two instruments were used to collect information on human failures: objective laboratory data and a human failure questionnaire. The results of human failures from the objective data were used to test for the deadline hypothesis and also to validate the human failure questionnaire. To explain why the human failures occurred, data were collected from a four-part, closed choice questionnaire administered to two groups of scientists, engineers, and technicians, working together against a deadline to produce an engineering prototype of a particle accelerator

  12. Trends in radiological and environmental protection at high energy accelerator laboratories

    International Nuclear Information System (INIS)

    Perry, D.R.; Shaw, K.B.; Stapleton, G.B.; Thomas, R.H.

    1991-03-01

    The serious study of high-energy particle accelerator radiological protection began in the early 1950s and has continued since then. This paper treats the subject in seven stages, and begins by briefly reviewing the work done until the 80s, which comprises the first five stages. These are, observation of high radiation levels, shielding studies, dosimetry, induced activity and the environmental effects. The sixth stage, control by legislation and regulation, is discussed in detail. Over the past twenty years there have been significant additions to radiological protection standards: from a scientifically based estimate of risk to a social desire to reduce exposure to levels determined only by the ''best practical means (BPM)'' or as it is currently understood in the United States of America ''best available technology (BAT)''. The implications of this trend are explored, and the success with which changing standards have been followed is studied with the aid of data derived from personnel doses. The last stage is the decommissioning or disposal of high energy accelerators. (author)

  13. Addendum to a proposal for ATLAS: a precision heavy-ion accelerator at Argonne National Laboratory

    International Nuclear Information System (INIS)

    1978-12-01

    This revised proposal for the construction of the Argonne Tandem-Linac Accelerator System (ATLAS) is in all essentials the same as the proposal originally presented to NUSAC in March 1978. The only differences worth mentioning are the plan to expand the experimental area somewhat more than was originally proposed and an increased cost, brought about principally by inflation. The outline presented is the same as in the original document, reproduced for the convenience of the reader. The objective of the proposed Argonne Tandem-Linac Accelerator System (ATLAS) is to provide precision beams of heavy ions for nuclear physics research in the region of projectile energies comparable to nuclear binding energies (5 to 25 MeV/A). By using the demonstrated potential of superconducting rf technology, beams of exceptional quality and flexibility can be obtained. The proposed system is designed to provide beams with tandem-like energy resolution and ease of energy variation, and the energy range is comparable to that of a approx. 50 MV tandem. In addition, the beam will be bunched into very short (approx. 50 psec) pulses, permitting fast-timing measurements that can open up major new experimental approaches

  14. Seawater-based wastewater accelerates development of aerobic granular sludge: A laboratory proof-of-concept.

    Science.gov (United States)

    Li, Xiling; Luo, Jinghai; Guo, Gang; Mackey, Hamish R; Hao, Tianwei; Chen, Guanghao

    2017-05-15

    This study aimed to develop an aerobic granular sludge process for the efficient treatment of highly saline wastewater and understand the granulation process in a seawater-based multi-ion matrix. Five identical sequencing batch airlift reactors (SBARs) are used to treat synthetic saline sewage with different proportions of real seawater (0%-100%). The results confirm that aerobic granular sludge can be successfully developed with various proportions of seawater up to 100% and show that seawater not only significantly accelerates granulation but also generates stronger granular structures than does freshwater. The increased presence of gel-forming alginate-like exopolysaccharides in the granules explains why a greater proportion of seawater leads to higher density and improves the cohesive strength of the granules. SEM-EDX analysis further revealed substantial presence of both Ca 2+ and Mg 2+ phosphate in the granule core as well as in the outer layers providing extra bridging forces in addition to alginate-like exopolysaccharides for accelerating the granule formation and maintaining the structure. It is hoped that this work could explore another approach for saline sewage treatment and bring some clues for the mystery of granulation mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Can Accelerators Accelerate Learning?

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  16. Can Accelerators Accelerate Learning?

    Science.gov (United States)

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

    2009-03-01

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

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

    International Nuclear Information System (INIS)

    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

    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

  18. ATLAS: a proposal for a precision heavy ion accelerator at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-02-01

    The objective of the proposed Argonne Tandem-Linac Accelerator System (ATLAS) is to provide precision beams of heavy ions for nuclear physics research in the region of projectile energies comparable to nuclear binding energies (5-25 MeV/A). By using the demonstrated potential of superconducting rf technology, beams of exceptional quality and flexibility can be obtained. The system is designed to provide beams with tandem-like energy resolution and ease of energy variation, the energy range is comparable to that of a approx. 50 MV tandem and, in addition, the beam will be bunched into very short (approx. 50 psec) pulses, permitting fast-timing measurements that can open up major new experimental approaches.

  19. Future directions in controlling the LAMPF-PSR accelerator complex at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Stuewe, R.; Schaller, S.; Bjorklund, E.

    1992-01-01

    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-server model-based data acquisition and control system. An increased use of distributed intelligence at both the front-end and the operator interface is a key element of the projects. (author)

  20. ATLAS: a proposal for a precision heavy ion accelerator at Argonne National Laboratory

    International Nuclear Information System (INIS)

    1978-02-01

    The objective of the proposed Argonne Tandem-Linac Accelerator System (ATLAS) is to provide precision beams of heavy ions for nuclear physics research in the region of projectile energies comparable to nuclear binding energies (5-25 MeV/A). By using the demonstrated potential of superconducting rf technology, beams of exceptional quality and flexibility can be obtained. The system is designed to provide beams with tandem-like energy resolution and ease of energy variation, the energy range is comparable to that of a approx. 50 MV tandem and, in addition, the beam will be bunched into very short (approx. 50 psec) pulses, permitting fast-timing measurements that can open up major new experimental approaches

  1. Development of a high brightness electron gun for the Accelerator Test Facility at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Batchelor, K.; Kirk, H.; Sheehan, J.; Woodle, M.; McDonald, K.

    1988-01-01

    An electron gun utilizing a radio frequency accelerating cavity operating at a frequency of 2856 MHZ is described. Low level tests of a model cavity designed for use with either a thermionic or laser driven photo-cathode are presented. Calculations for a laser driven photo-cathode at a bunch charge of 1nC in a 5 psec bunch are given. With this configuration we hope to achieve an emittance (γσ/sub x/σ/sub x/) of 5 to 10 /times/ 10/sup /minus/6/ m /center dot/ rad at an output energy of 4.85 MeV for a 1nC charge. 9 refs., 10 figs., 4 tabs

  2. Internal plasma potential measurements of a Hall thruster using xenon and krypton propellant

    International Nuclear Information System (INIS)

    Linnell, Jesse A.; Gallimore, Alec D.

    2006-01-01

    For krypton to become a realistic option for Hall thruster operation, it is necessary to understand the performance gap between xenon and krypton and what can be done to reduce it. A floating emissive probe is used with the Plasmadynamics and Electric Propulsion Laboratory's High-speed Axial Reciprocating Probe system to map the internal plasma potential structure of the NASA-173Mv1 Hall thruster [R. R. Hofer, R. S. Jankovsky, and A. D. Gallimore, J. Propulsion Power 22, 721 (2006); and ibid.22, 732 (2006)] using xenon and krypton propellant. Measurements are taken for both propellants at discharge voltages of 500 and 600 V. Electron temperatures and electric fields are also reported. The acceleration zone and equipotential lines are found to be strongly linked to the magnetic-field lines. The electrostatic plasma lens of the NASA-173Mv1 Hall thruster strongly focuses the xenon ions toward the center of the discharge channel, whereas the krypton ions are defocused. Krypton is also found to have a longer acceleration zone than the xenon cases. These results explain the large beam divergence observed with krypton operation. Krypton and xenon have similar maximum electron temperatures and similar lengths of the high electron temperature zone, although the high electron temperature zone is located farther downstream in the krypton case

  3. Halls Lake 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or...

  4. Hall Thruster Thermal Modeling and Test Data Correlation

    Science.gov (United States)

    Myers, James

    2016-01-01

    HERMeS - Hall Effect Rocket with Magnetic Shielding. Developed through a joint effort by NASA/GRC and the Jet Propulsion Laboratory (JPL). Design goals: High power (12.5 kW) high Isp (3000 sec), high efficiency (> 60%), high throughput (10,000 kg), reduced plasma erosion and increased life (5 yrs) to support Asteroid Redirect Robotic Mission (ARRM). Further details see "Performance, Facility Pressure Effects and Stability Characterization Tests of NASAs HERMeS Thruster" by H. Kamhawi and team. Hall Thrusters (HT) inherently operate at elevated temperatures approx. 600 C (or more). Due to electric magnetic (E x B) fields used to ionize and accelerate propellant gas particles (i.e., plasma). Cooling is largely limited to radiation in vacuum environment.Thus the hardware components must withstand large start-up delta-T's. HT's are constructed of multiple materials; assorted metals, non-metals and ceramics for their required electrical and magnetic properties. To mitigate thermal stresses HT design must accommodate the differential thermal growth from a wide range of material Coef. of Thermal Expansion (CTEs). Prohibiting the use of some bolted/torqued interfaces.Commonly use spring loaded interfaces, particularly at the metal-to-ceramic interfaces to allow for slippage.However most component interfaces must also effectively conduct heat to the external surfaces for dissipation by radiation.Thus contact pressure and area are important.

  5. The quantum hall effect

    International Nuclear Information System (INIS)

    El-Arabi, N. M.

    1993-01-01

    Transport phenomena in two dimensional semiconductors have revealed unusual properties. In this thesis these systems are considered and discussed. The theories explain the Integral Quantum Hall Effect (IQHE) and the Fractional Quantum Hall Effect (FQHE). The thesis is composed of five chapters. The first and the second chapters lay down the theory of the IQHE, the third and fourth consider the theory of the FQHE. Chapter five deals with the statistics of particles in two dimension. (author). Refs

  6. Evaluation of the technique 'wire on the screw' in laboratory accelerated essays

    International Nuclear Information System (INIS)

    Calderon, J.; Arroyave, C.

    1998-01-01

    The CLIMAT essay has been employed as for the micro climate corrosiveness determination as for large geographic zones, allowing the qualification of corrosiveness of the interesting sites, the maps raising, the materials evaluation and the pollution focus localization. However, its utility, this has not been deepen in the understanding of his characteristics and corrosive process that it experiments. With the purpose in order to deepen in its knowledge and evaluating the useful possibilities in an immersion-emersion accelerated essay, it was accomplishment the present work. For this, was employed spiral aluminium manometers forming a galvanized pair with copper and steel screws, which were exposed to representative dissolutions of rainwater of the rural, urban and marine environment. It was measured the electrode potential for the essays, the corrosion velocities were determined gravimetrically, it was drawing polarization curves and they were characterized the corrosion products by X-ray diffraction (XRD), Infrared spectrometry (Ftir), Scanning Electron Microscopy (Sem) and stereoscopic microscope. The results allow to conclude that must pass sometime for what galvanic action was established. The potential evolution after that initial time, is approximately the same for the two pairs, for which the main losing of mass obtained in the Al-Cu screw has to be explained with kinetic arguments offered for polarization curves. The main corrosion product is bayerite (Al(OH) 3 ), with greater crystallinity in Cl - dissolution than in SO 4 (2-) and with morphologies very influenced by environment. (Author)

  7. Construction and Performance of a Liquid Argon Calorimeter for use in Experiment E-706 at the Fermi National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    DeSoi, William Edward [Rochester U.

    1990-01-01

    The subject of this thesis is a liquid argon calorimeter developed by the E-706 collaboration. This device was used in measuring the energy content of showers produced by the interaction of nucleons with 530 GeV/c pions at the Fermi National Accelerator Laboratory. A description of the calorimeter's construction and design considerations precedes the analysis of its performance, which is the central topic to be discussed. The calorimeter was found to have an intrinsic energy for electromagnetic showers of 14.5%/$\\sqrt{E}$ and for hadronic showers a resolution of 183%/$\\sqrt{E}$. The position resolution of showers for the calorimeter was found to be 1.0 mm or better for energies greater than 2.0 GeV.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-01

    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

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

    International Nuclear Information System (INIS)

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

    2001-01-01

    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

  10. Hall viscosity of hierarchical quantum Hall states

    Science.gov (United States)

    Fremling, M.; Hansson, T. H.; Suorsa, J.

    2014-03-01

    Using methods based on conformal field theory, we construct model wave functions on a torus with arbitrary flat metric for all chiral states in the abelian quantum Hall hierarchy. These functions have no variational parameters, and they transform under the modular group in the same way as the multicomponent generalizations of the Laughlin wave functions. Assuming the absence of Berry phases upon adiabatic variations of the modular parameter τ, we calculate the quantum Hall viscosity and find it to be in agreement with the formula, given by Read, which relates the viscosity to the average orbital spin of the electrons. For the filling factor ν =2/5 Jain state, which is at the second level in the hierarchy, we compare our model wave function with the numerically obtained ground state of the Coulomb interaction Hamiltonian in the lowest Landau level, and find very good agreement in a large region of the complex τ plane. For the same example, we also numerically compute the Hall viscosity and find good agreement with the analytical result for both the model wave function and the numerically obtained Coulomb wave function. We argue that this supports the notion of a generalized plasma analogy that would ensure that wave functions obtained using the conformal field theory methods do not acquire Berry phases upon adiabatic evolution.

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

    International Nuclear Information System (INIS)

    Groeber, S; Vetter, M; Eckert, B; Jodl, H-J

    2007-01-01

    We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration (accuracy Δg ∼ 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(ψ), that the Earth's effective gravitational acceleration g depends on the angle of latitude ψ. Then, we present all necessary formula to deduce g(ψ) 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(ψ) 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

  12. Construction of a open-quotes black neutron detectorclose quotes at the University of Massachusetts-Lowell Accelerator Laboratory

    International Nuclear Information System (INIS)

    Bertone, P.F.; DeSimone, D.J.; Dugan, P.F.

    1992-01-01

    In many experiments involving fast neutrons generated in nuclear reactions initiated by accelerator produced charged particle beams, it is important to be able to determine accurately the neutron yield from the target. A detector suitable for such applications should have: a constant efficiency over a large energy range; a fast time response; and the ability to discriminate between gamma rays and neutrons. The authors have constructed a open-quotes black neutron detectorclose quotes based on the design of Poenitz that has these characteristics. At the Lowell Van de Graaff accelerator laboratory neutrons are produced via the 7 Li(p,n) 7 Be reaction using a pulsed proton beam which impinges on metallic lithium targets. The pulsed beam enables the detector to be used in a time-of-flight spectrometer. Use of BC501 liquid scintillator permits neutron-gamma discrimination. The scintillator is viewed by five RCA 48796 photo tubes. The detector is housed in a massive shield of lead, polyethylene and lithium carbonate. The characteristics and use of this detector will be discussed

  13. Prototype dining hall energy efficiency study

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucchi, R.P.; Bailey, S.A.; Zimmerman, P.W.

    1988-06-01

    The energy consumption of food service facilities is among the highest of any commercial building type, owing to the special requirements for food preparation, sanitation, and ventilation. Consequently, the US Air Force Engineering and Services Center (AFESC) contracted with Pacific Northwest Laboratory (PNL) to collect and analyze end-use energy consumption data for a prototypical dining hall and make specific recommendations on cost-effective energy conservation options. This information will be used to establish or update criteria for dining hall designs and retrofits as appropriate. 6 refs., 21 figs., 23 tabs.

  14. Iodine Hall Thruster

    Science.gov (United States)

    Szabo, James

    2015-01-01

    Iodine enables dramatic mass and cost savings for lunar and Mars cargo missions, including Earth escape and near-Earth space maneuvers. The demonstrated throttling ability of iodine is important for a singular thruster that might be called upon to propel a spacecraft from Earth to Mars or Venus. The ability to throttle efficiently is even more important for missions beyond Mars. In the Phase I project, Busek Company, Inc., tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high-flow iodine feed system and supported by an existing Busek hollow cathode flowing xenon gas. The Phase I propellant feed system was evolved from a previously demonstrated laboratory feed system. Throttling of the thruster between 2 and 11 kW at 200 to 600 V was demonstrated. Testing showed that the efficiency of iodine fueled BHT-8000 is the same as with xenon, with iodine delivering a slightly higher thrust-to-power (T/P) ratio. In Phase II, a complete iodine-fueled system was developed, including the thruster, hollow cathode, and iodine propellant feed system. The nominal power of the Phase II system is 8 kW; however, it can be deeply throttled as well as clustered to much higher power levels. The technology also can be scaled to greater than 100 kW per thruster to support megawatt-class missions. The target thruster efficiency for the full-scale system is 65 percent at high specific impulse (Isp) (approximately 3,000 s) and 60 percent at high thrust (Isp approximately 2,000 s).

  15. Shielding consideration for the SSCL experimental halls

    International Nuclear Information System (INIS)

    Bull, J.; Coyne, J.; Mokhov, N.; Stapleton, G.

    1994-03-01

    The Superconducting Super Collider which is being designed and built in Waxahachie, Texas consists Of series of proton accelerators, culminating in a 20 Te proton on proton collider. The collider will be in a tunnel which will be 87 km in circumference and. on average about 30 meters underground. The present design calls for two large interaction halls on the east side of the ring. The shielding for these halls is being designed for an interaction rate of 10 9 Hz or 10 16 interactions per year, based on 10 7 seconds per operational year. SSC guidelines require that the shielding be designed to meet the criterion of 1mSv per year for open areas off site 2mSv per year for open areas on site, and 2mSv per year for controlled areas. Only radiation workers will be routinely allowed to work in controlled areas. It should be pointed that there is a potential for an accidental full beam loss in either of the experimental halls, and this event would consist of the loss of the full circulating beam up to 4 x 10 14 protons. With the present design. the calculated dose equivalent for this event is about 10% of the annual dose equivalent for the normal p-p interactions, so that die accident condition does not control the shielding. If, for instance, local shielding within the experimental hall is introduced into the calculations, this could change. The shielding requirements presented here are controlled by the normal p-p interactions. Three important questions were addressed in the present calculations. They are (1) the thickness of the roof over the experimental halls, (2) the configuration of the shafts and adits which give access to the halls, and (3) the problem of ground water and air activation

  16. Aerial radiological survey of the Fermi National accelerator Laboratory and surrounding area, Batavia, Illinois. Data of survey: 12-14 May 1977

    International Nuclear Information System (INIS)

    Jobst, J.E.

    1981-01-01

    An aerial radiological survey was conducted over the facilities of the Fermi National Accelerator Laboratory (Fermilab) near Batavia, Illinois on 12-14 May 1977. The survey was flown at an altitude of 91 m by a helicopter containing 20 sodium iodide detectors. The line spacing was also 91 m. Enhanced gamma exposure rate levels, which could be attributed to Fermilab operations, were observed at seven locations. One additional anomaly, not related to the Laboratory, was also discovered

  17. Multi-MW accelerator target material properties under proton irradiation at Brookhaven National Laboratory linear isotope producer

    Science.gov (United States)

    Simos, N.; Ludewig, H.; Kirk, H.; Dooryhee, E.; Ghose, S.; Zhong, Z.; Zhong, H.; Makimura, S.; Yoshimura, K.; Bennett, J. R. J.; Kotsinas, G.; Kotsina, Z.; McDonald, K. T.

    2018-05-01

    The effects of proton beams irradiating materials considered for targets in high-power accelerator experiments have been studied using the Brookhaven National Laboratory's (BNL) 200 MeV proton linac. A wide array of materials and alloys covering a wide range of the atomic number (Z) are being scoped by the high-power accelerator community prompting the BNL studies to focus on materials representing each distinct range, i.e. low-Z, mid-Z and high-Z. The low range includes materials such as beryllium and graphite, the midrange alloys such as Ti-6Al-4V, gum metal and super-Invar and finally the high-Z range pure tungsten and tantalum. Of interest in assessing proton irradiation effects are (a) changes in physiomechanical properties which are important in maintaining high-power target functionality, (b) identification of possible limits of proton flux or fluence above which certain materials cease to maintain integrity, (c) the role of material operating temperature in inducing or maintaining radiation damage reversal, and (d) phase stability and microstructural changes. The paper presents excerpt results deduced from macroscopic and microscopic post-irradiation evaluation (PIE) following several irradiation campaigns conducted at the BNL 200 MeV linac and specifically at the isotope producer beam-line/target station. The microscopic PIE relied on high energy x-ray diffraction at the BNL NSLS X17B1 and NSLS II XPD beam lines. The studies reveal the dramatic effects of irradiation on phase stability in several of the materials, changes in physical properties and ductility loss as well as thermally induced radiation damage reversal in graphite and alloys such as super-Invar.

  18. The quantized Hall effect

    International Nuclear Information System (INIS)

    Klitzing von, K.

    1989-01-01

    The quantized Hall effect is theoretically explained in detail as are its basic properties. The explanation is completed with the pertinent mathematical relations and illustrative figures. Experimental data are critically assessed obtained by quantum transport measurement in a magnetic field on two-dimensional systems. The results are reported for a MOSFET silicon transistor and for GaAs-Al x Ga 1-x As heterostructures. The application is discussed of the quantized Hall effect in determining the fine structure constant or in implementing the resistance standard. (M.D.). 27 figs., 57 refs

  19. Intrinsic superspin Hall current

    Science.gov (United States)

    Linder, Jacob; Amundsen, Morten; Risinggârd, Vetle

    2017-09-01

    We discover an intrinsic superspin Hall current: an injected charge supercurrent in a Josephson junction containing heavy normal metals and a ferromagnet generates a transverse spin supercurrent. There is no accompanying dissipation of energy, in contrast to the conventional spin Hall effect. The physical origin of the effect is an antisymmetric spin density induced among transverse modes ky near the interface of the superconductor arising due to the coexistence of p -wave and conventional s -wave superconducting correlations with a belonging phase mismatch. Our predictions can be tested in hybrid structures including thin heavy metal layers combined with strong ferromagnets and ordinary s -wave superconductors.

  20. Hall magnetohydrodynamics of neutral layers

    International Nuclear Information System (INIS)

    Huba, J.D.; Rudakov, L.I.

    2003-01-01

    New analytical and numerical results of the dynamics of inhomogeneous, reversed field current layers in the Hall limit (i.e., characteristic length scales < or approx. the ion inertial length) are presented. Specifically, the two- and three-dimensional evolution of a current layer that supports a reversed field plasma configuration and has a density gradient along the current direction is studied. The two-dimensional study demonstrates that a density inhomogeneity along the current direction can dramatically redistribute the magnetic field and plasma via magnetic shock-like or rarefaction waves. The relative direction between the density gradient and current flow plays a critical role in the evolution of the current sheet. One important result is that the current sheet can become very thin rapidly when the density gradient is directed opposite to the current. The three-dimensional study uses the same plasma and field configuration as the two-dimensional study but is also initialized with a magnetic field perturbation localized along the current channel upstream of the plasma inhomogeneity. The perturbation induces a magnetic wave structure that propagates in the direction of the electron drift (i.e., opposite to the current). The propagating wave structure is a Hall phenomenon associated with magnetic field curvature. The interaction between the propagating wave structure and the evolving current layer can lead to rapid magnetic field line reconnection. The results are applied to laboratory and space plasma processes

  1. Representing Value as Digital Object: A Discussion of Transferability and Anonymity; Digital Library Initiatives of the Deutsche Forschungsgemeinschaft; CrossRef Turns One; Fermi National Accelerator Laboratory (Fermilab).

    Science.gov (United States)

    Kahn, Robert E.; Lyons, Patrice A.; Brahms, Ewald; Brand, Amy; van den Bergen, Mieke

    2001-01-01

    Includes four articles that discuss the use of digital objects to represent value in a network environment; digital library initiatives at the central public funding organization for academic research in Germany; an application of the Digital Object Identifier System; and the Web site of the Fermi National Accelerator Laboratory. (LRW)

  2. Construction and operation of a 10 MeV electron accelerator and associated experimental facilities at Brookhaven National Laboratory, Upton, New York. Environmental assessment

    International Nuclear Information System (INIS)

    1994-02-01

    The purpose of this environmental impact statement is to determine whether there would be significant environmental impacts associated with the construction of an experimental facility at Brookhaven National Laboratory for radiation chemistry research and operation of the 10-MeV electron accelerator proposed for it. The document describes the need for action, alternative actions, the affected environment, and potential environmental impacts

  3. Hall effect in hopping regime

    International Nuclear Information System (INIS)

    Avdonin, A.; Skupiński, P.; Grasza, K.

    2016-01-01

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  4. Hall effect in hopping regime

    Energy Technology Data Exchange (ETDEWEB)

    Avdonin, A., E-mail: avdonin@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Skupiński, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Grasza, K. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Institute of Electronic Materials Technology, ul. Wólczyńska 133, 01-919 Warszawa (Poland)

    2016-02-15

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  5. Final environmental impact statement. Proton--Proton Storage Accelerator Facility (ISABELLE), Brookhaven National Laboratory, Upton, New York

    International Nuclear Information System (INIS)

    1978-08-01

    An Environmental Impact Statement for a proposed research facility (ISABELLE) to be built at Brookhaven National Laboratory (BNL) is presented. It was prepared by the Department of Energy (DOE) following guidelines issued for such analyses. In keeping with DOE policy, this statement presents a concise and issues-oriented analysis of the significant environmental effects associated with the proposed action. ISABELLE is a proposed physics research facility where beams of protons collide providing opportunities to study high energy interactions. The facility would provide two interlaced storage ring proton accelerators, each with an energy up to 400 GeV intersecting in six experimental areas. The rings are contained in a tunnel with a circumference of 3.8 km (2.3 mi). The facility will occupy 250 ha (625 acres) in the NW corner of the existing BNL site. A draft Environmental Impact Statement for this proposed facility was issued for public review and comment by DOE on February 21, 1978. The principal areas of concern expressed were in the areas of radiological impacts and preservation of cultural values. After consideration of these comments, appropriate actions were taken and the text of the statement has been amended to reflect the comments. The text was annotated to indicate the origin of the comment. The Appendices contain a glossary of terms and listings of metric prefixes and conversions and symbols and abbreviations

  6. The Monty Hall Dilemma.

    Science.gov (United States)

    Granberg, Donald; Brown, Thad A.

    1995-01-01

    Examines people's behavior in the Monty Hall Dilemma (MHD), in which a person must make two decisions to win a prize. In a series of five studies, found that people misapprehend probabilities in the MHD. Discusses the MHD's relation to illusion of control, belief perseverance, and the status quo bias. (RJM)

  7. The Isolde experimental hall

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    General view of the Isotope-Separator On-Line (ISOLDE) hall. ISOLDE is dedicated to the production of a large variety of radioactive ion beams for many different experiments. Rare isotopes can be produced allowing the study of spectra for neutrino beam production.

  8. Hall Sweet Home

    Science.gov (United States)

    Oguntoyinbo, Lekan

    2011-01-01

    Many urban and commuter universities have their sights set on students who are unlikely to connect with the college and likely to fail unless the right strategies are put in place to help them graduate. In efforts to improve retention rates, commuter colleges are looking to an unusual suspect: residence halls. The author discusses how these…

  9. Anomalous Hall effect

    Czech Academy of Sciences Publication Activity Database

    Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.

    2010-01-01

    Roč. 82, č. 2 (2010), s. 1539-1592 ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010

  10. Laurance David Hall.

    Science.gov (United States)

    Coxon, Bruce

    2011-01-01

    An account is given of the life, scientific contributions, and passing of Laurance David Hall (1938-2009), including his early history and education at the University of Bristol, UK, and the synthesis and NMR spectroscopy of carbohydrates and other natural products during ∼20 years of research and teaching at the University of British Columbia in Vancouver, Canada. Lists of graduate students, post-doctoral fellows, and sabbatical visitors are provided for this period. Following a generous endowment by Dr. Herchel Smith, Professor Hall built a new Department of Medicinal Chemistry at Cambridge University, UK, and greatly expanded his researches into the technology and applications of magnetic resonance imaging (MRI) and zero quantum NMR. MRI technology was applied both to medical problems such as the characterization of cartilage degeneration in knee joints, the measurement of ventricular function, lipid localization in animal models of atherosclerosis, paramagnetic metal complexes of polysaccharides as contrast agents, and studies of many other anatomical features, but also to several aspects of materials analysis, including food analyses, process control, and the elucidation of such physical phenomena as the flow of liquids through porous media, defects in concrete, and the visualization of fungal damage to wood. Professor Hall's many publications, patents, lectures, and honors and awards are described, and also his successful effort to keep the Asilomar facility in Pacific Grove, California as the alternating venue for the annual Experimental NMR Conference. Two memorial services for Professor Hall are remembered. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Paris, E.

    2004-01-01

    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

  12. Design of DC-60 specialized accelerator for the Inter-disciplinary Laboratory Complex by the L.N. Gumilev Eurasian State University

    International Nuclear Information System (INIS)

    Gikal, B.N.; Itkis, M.G.; Dmitriev, S.N.; Gul'bekyan, G.G.; Franko, J.; ); Kadyrzhanov, K.K.; Arzumanov, A.A.; Borisenko, A.N.; Lysukhin, S.N.

    2001-01-01

    Design of the Inter-disciplinary Laboratory Complex by the L.N. Eurasian State University allows development and implementation of specialized heavy ion accelerator. According requirements of research programme the most optimal accelerator is compact cyclotron with fixed magnetic field and varying frequency of high-frequency system in dependence on mass rate to accelerated ions charge. The accelerator has two accelerating modes - on 4 and 6 harmonics, that allow to accelerate ions from C to Xe with energies from 0.4 to 1.6 MeV/nucleon. The beam take out is occurring by electrostatic deflector. The beam will be transporting to physical unit for research conducting. The cyclotron is equipped with ECR source and axial beam injection system.The extending voltage on the ion source is 10-25 k W. On the injection line it is planning to create the channel - after analyzing magnet -for using of satellite beams, that allow to conduct experiments on a low energy ions beams. In all accelerating modes the ions energy does not exceeds the Coulomb barrier and so the unit is radiation safe. The cyclotron complex could be used for fulfilment of a wide circle of research and applied tasks, as well as for students and postgraduates training

  13. Radiation conditions in the ring hall of the IHEP proton synchrotron

    International Nuclear Information System (INIS)

    Borodin, V.E.; Ermolenko, L.S.; Obryashchikova, L.P.

    1975-01-01

    The paper presents the results on studying the radiation conditions caused by induced radioactivity of the accelerator units in the ring hall. The data on the induced radioactivity level just on the ring vacuum chamber are reported. Radiation conditions in the most characteristic areas of the hall are considered. The changes in time of the dose rate at the internal target and at the entrance to the hall are shown

  14. Spin Hall effects

    Science.gov (United States)

    Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.

    2015-10-01

    Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical

  15. Low-Cost, High-Performance Hall Thruster Support System

    Science.gov (United States)

    Hesterman, Bryce

    2015-01-01

    Colorado Power Electronics (CPE) has built an innovative modular PPU for Hall thrusters, including discharge, magnet, heater and keeper supplies, and an interface module. This high-performance PPU offers resonant circuit topologies, magnetics design, modularity, and a stable and sustained operation during severe Hall effect thruster current oscillations. Laboratory testing has demonstrated discharge module efficiency of 96 percent, which is considerably higher than current state of the art.

  16. Essay of accelerator R and D in a small laboratory of an university. Head ion IH linac for fusion material. 1983-1985

    International Nuclear Information System (INIS)

    Hattori, Toshiyuki

    2005-01-01

    The linear accelerator of Inter-Digital H type (IH linac) is known to have a high shunt impedance. Research Laboratory for Nuclear Reactors of Tokyo Institute of Technology introduced an IH linac for fusion materials irradiation test in 1983. The beam injector was a tandem electrostatic accelerator. The IH linac was designed and fabricated based on the developmental work at Institute for Nuclear Study of University of Tokyo. The processes of component alignment, cold test and start-up operation are described. Educational aspect of the project is also reviewed. (K.Y.)

  17. 27 Febuary 2012 - US DoE Associate Director of Science for High Energy Physics J. Siegrist visiting the LHC superconducting magnet test hall with adviser J.-P. Koutchouk and engineer M. Bajko; in CMS experimental cavern with Spokesperson J. Incadela;in ATLAS experimental cavern with Deputy Spokesperson A. Lankford; in ALICE experimental cavern with Spokesperson P. Giubellino; signing the guest book with Director for Accelerators and Technology S. Myers.

    CERN Multimedia

    Laurent Egli

    2012-01-01

    27 Febuary 2012 - US DoE Associate Director of Science for High Energy Physics J. Siegrist visiting the LHC superconducting magnet test hall with adviser J.-P. Koutchouk and engineer M. Bajko; in CMS experimental cavern with Spokesperson J. Incadela;in ATLAS experimental cavern with Deputy Spokesperson A. Lankford; in ALICE experimental cavern with Spokesperson P. Giubellino; signing the guest book with Director for Accelerators and Technology S. Myers.

  18. Horizontal Accelerator

    Data.gov (United States)

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

  19. Paired Hall states

    International Nuclear Information System (INIS)

    Greiter, M.

    1992-01-01

    This dissertation contains a collection of individual articles on various topics. Their significance in the corresponding field as well as connections between them are emphasized in a general and comprehensive introduction. In the first article, the author explores the consequences for macroscopic effective Lagrangians of assuming that the momentum density is proportional to the flow of conserved current. The universal corrections obtained for the macroscopic Lagrangian of a superconductor describe the London Hall effect, and provide a fully consistent derivation of it. In the second article, a heuristic principle is proposed for quantized Hall states: the existence and incompressibility of fractionally quantized Hall states is explained by an argument based on an adiabatic localization of magnetic flux, the process of trading uniform flux for an equal amount of fictitious flux attached to the particles. This principle is exactly implemented in the third article. For a certain class of model Hamiltonians, the author obtains Laughlin's Jastrow type wave functions explicitly from a filled Landau level, by smooth extrapolation in quantum statistics. The generalization of this analysis to the torus geometry shows that theorems restricting the possibilities of quantum statistics on closed surfaces are circumvented in the presence of a magnetic field. In the last article, the existence is proposed of a novel incompressible quantum liquid, a paired Hall state, at a half filled Landau level. This state arises adiabatically from free fermions in zero magnetic field, and reduces to a state previously proposed by Halperin in the limit of tightly bound pairs. It supports unusual excitations, including neutral fermions and charge e/4 anyons with statistical parameter θ = π/8

  20. Guild Hall retrofit

    Energy Technology Data Exchange (ETDEWEB)

    1984-08-01

    This report demonstrates the economic viability of an exterior rewrap retrofit performed on a public community facility for the performing arts. This facility originally consisted of two mess halls built by the American army. The exterior retrofit consisted of constructing a super-insulated passageway to link the two halls as well as completely wrapping the facility with six millimetre polyethylene to provide an airtight barrier. The roofs and walls were reinsulated and insulation levels were increased to RSI 10.5 in the ceilings and RSI 7.7 in the walls. The installation of a propane fuelled furnace was also included in the retrofit package. Prior to the renovations and retrofitting, the Guild Hall facility was almost unusable. The demonstration project transformed the cold, drafty buildings into an attractive, comfortable and functional centre for the performing arts. Heating requirements have been reduced to 500 MJ/m {sup 2} of floor space annually compared to a predicted 1,760 MJ/m{sup 2} of floor space based on HOTCAN analysis of the heating requirements without the energy conservation measures. 9 figs., 10 tabs.

  1. Quantum critical Hall exponents

    CERN Document Server

    Lütken, C A

    2014-01-01

    We investigate a finite size "double scaling" hypothesis using data from an experiment on a quantum Hall system with short range disorder [1-3]. For Hall bars of width w at temperature T the scaling form is w(-mu)T(-kappa), where the critical exponent mu approximate to 0.23 we extract from the data is comparable to the multi-fractal exponent alpha(0) - 2 obtained from the Chalker-Coddington (CC) model [4]. We also use the data to find the approximate location (in the resistivity plane) of seven quantum critical points, all of which closely agree with the predictions derived long ago from the modular symmetry of a toroidal sigma-model with m matter fields [5]. The value nu(8) = 2.60513 ... of the localisation exponent obtained from the m = 8 model is in excellent agreement with the best available numerical value nu(num) = 2.607 +/- 0.004 derived from the CC-model [6]. Existing experimental data appear to favour the m = 9 model, suggesting that the quantum Hall system is not in the same universality class as th...

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

    Energy Technology Data Exchange (ETDEWEB)

    Paris, E.

    2004-04-05

    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

  3. High power beam test and measurement of emittance evolution of a 1.6-cell photocathode RF gun at Pohang Accelerator Laboratory

    International Nuclear Information System (INIS)

    Park, Jang-Ho; Park, Sung-Ju; Kim, Changbum; Huang, Jung-Yun; Ko, In Soo; Parc, Yong-Woon; Hong, Ju-Ho; Xiang Dao; Wang, Xijie

    2007-01-01

    A Brookhaven National Laboratory (BNL) GUN-IV type photocathode rf gun has been fabricated to use in femtosecond electron diffraction (FED), femtosecond far infrared radiation (fs-FIR) facility, and X-ray free electron laser (XFEL) facilities at the Pohang Accelerator Laboratory (PAL). The gun consists of a 1.6-cell cavity with a copper cathode, a solenoid magnet, beam diagnostic components and auxiliary systems. We report here the measurement of the basic beam parameters which confirm a successful fabrication of the photocathode RF gun system. The emittance evolution is measured by an emittance meter and compared with the PARMELA simulation, which shows a good agreement. (author)

  4. Topological Hall and Spin Hall Effects in Disordered Skyrmionic Textures

    OpenAIRE

    N'diaye, P. B.; Akosa, C. A.; Manchon, A.

    2016-01-01

    We carry out a throughout study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy band structure in the multiprobe Landauer-B\\"uttiker formalism and their link to the effective magnetic field emerging from the real space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and found that the adiabatic a...

  5. Quantum hall effect. A perspective

    International Nuclear Information System (INIS)

    Aoki, Hideo

    2006-01-01

    Novel concepts and phenomena are emerging recently in the physics of quantum Hall effect. This article gives an overview, which starts from the fractional quantum Hall system viewed as an extremely strongly correlated system, and move on to present various phenomena involving internal degrees of freedom (spin and layer), non-equilibrium and optical properties, and finally the spinoff to anomalous Hall effect and the rotating Bose-Einstein condensate. (author)

  6. Magnesium Hall Thruster

    Science.gov (United States)

    Szabo, James J.

    2015-01-01

    This Phase II project is developing a magnesium (Mg) Hall effect thruster system that would open the door for in situ resource utilization (ISRU)-based solar system exploration. Magnesium is light and easy to ionize. For a Mars- Earth transfer, the propellant mass savings with respect to a xenon Hall effect thruster (HET) system are enormous. Magnesium also can be combusted in a rocket with carbon dioxide (CO2) or water (H2O), enabling a multimode propulsion system with propellant sharing and ISRU. In the near term, CO2 and H2O would be collected in situ on Mars or the moon. In the far term, Mg itself would be collected from Martian and lunar regolith. In Phase I, an integrated, medium-power (1- to 3-kW) Mg HET system was developed and tested. Controlled, steady operation at constant voltage and power was demonstrated. Preliminary measurements indicate a specific impulse (Isp) greater than 4,000 s was achieved at a discharge potential of 400 V. The feasibility of delivering fluidized Mg powder to a medium- or high-power thruster also was demonstrated. Phase II of the project evaluated the performance of an integrated, highpower Mg Hall thruster system in a relevant space environment. Researchers improved the medium power thruster system and characterized it in detail. Researchers also designed and built a high-power (8- to 20-kW) Mg HET. A fluidized powder feed system supporting the high-power thruster was built and delivered to Busek Company, Inc.

  7. Spin Hall effect transistor

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, Joerg; Park, B.G.; Irvine, A.C.; Zarbo, Liviu; Rozkotová, E.; Němec, P.; Novák, Vít; Sinova, Jairo; Jungwirth, Tomáš

    2010-01-01

    Roč. 330, č. 6012 (2010), s. 1801-1804 ISSN 0036-8075 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.364, year: 2010

  8. Nuclear physics accelerator facilities

    International Nuclear Information System (INIS)

    1988-12-01

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

  9. Accelerator system model (ASM): A unique tool in exploring accelerator driven transmutation technologies (ADTT) system trade space

    Energy Technology Data Exchange (ETDEWEB)

    Myers, T.J.; Favale, A.J.; Berwald, D.H.; Burger, E.C.; Paulson, C.C.; Peacock, M.A.; Piaszczyk, C.M.; Piechowiak, E.M.; Rathke, J.W. [Northrop Grumman Corp., Bethpage, NY (United States). Advanced Technology and Development Center

    1997-09-01

    To aid in the development and optimization of emerging Accelerator Driven Transmutation Technology (ADTT) concepts, the Northrop Grumman Corporation, working together with G.H. Gillespie Associates and Los Alamos National Laboratory has developed a computational tool which combines both accelerator physics layout/analysis capabilities with engineering analysis capabilities to create a standardized platform to compare and contrast accelerator system configurations. In this context, the accelerator system configuration includes not only the accelerating structures, but also the major support systems such as the vacuum, thermal control, RF power, and cryogenic subsystem (if superconducting accelerator operation is investigated) as well as estimates of the costs for enclosures (accelerating tunnel and RF halls). This paper presents an overview of the Accelerator System Model (ASM) code flow, as well as a discussion of the data and analysis upon which it is based. Also presented is material which addresses the development of the evaluation criteria employed by this code including a presentation of the economic analysis methods, and a discussion of the cost database employed. The paper concludes with examples depicting completed and planned trade studies for both normal and superconducting accelerator applications. 8 figs.

  10. Quantum Hall Electron Nematics

    Science.gov (United States)

    MacDonald, Allan

    In 2D electron systems hosted by crystals with hexagonal symmetry, electron nematic phases with spontaneously broken C3 symmetry are expected to occur in the quantum Hall regime when triplets of Landau levels associated with three different Fermi surface pockets are partially filled. The broken symmetry state is driven by intravalley Coulombic exchange interactions that favor spontaneously polarized valley occupations. I will discuss three different examples of 2D electron systems in which this type of broken symmetry state is expected to occur: i) the SnTe (111) surface, ii) the Bi (111) surface. and iii) unbalanced bilayer graphene. This type of quantum Hall electron nematic state has so far been confirmed only in the Bi (111) case, in which the anisotropic quasiparticle wavefunctions of the broken symmetry state were directly imaged. In the SnTe case the nematic state phase boundary is controlled by a competition between intravalley Coulomb interactions and intervalley scattering processes that increase in relative strength with magnetic field. An in-plane Zeeman field alters the phase diagram by lifting the three-fold Landau level degeneracy, yielding a ground state energy with 2 π/3 periodicity as a function of Zeeman-field orientation angle. I will comment on the possibility of observing similar states in the absence of a magnetic field. Supported by DOE Division of Materials Sciences and Engineering Grant DE-FG03-02ER45958.

  11. Effect of Anode Dielectric Coating on Hall Thruster Operation

    International Nuclear Information System (INIS)

    Dorf, L.; Raitses, Y.; Fisch, N.J.; Semenov, V.

    2003-01-01

    An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The anode fall might affect the thruster lifetime and acceleration efficiency. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode

  12. Energy consumption of sport halls

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    The energy consumption of Finland's sports halls (ball games halls, ice hockey halls and swimming halls) represent approximately 1% of that of the country's whole building stock. In the light of the facts revealed by the energy study the potential energy saving rate in sports halls is 15-25%. The total savings would be something like FIM 30-40 million per annum, of which about a half would be achieved without energy-economic investments only by changing utilization habits and by automatic control measures. The energy-economic investments are for the most part connected with ventilation and their repayment period is from one to five years. On the basis of the energy study the following specific consumption are presented as target values: swimming halls: heat (kWh/m*H3/a)100, electricity (kWh/m*H3/a)35, water (l/m*H3/a)1000 icehockey halls (warm): heat (kWh/m*H3/a)25, electricity (kWh/m*H3/a)15, water (l/m*H3/a)200, ball games halls (multi-purpose halls): heat (kWh/m*H3/a)30, electricity (kWh/m*H3/a)25, water (l/m*H3/a)130. In the study the following points proved to be the central areas of energy saving in sports halls: 1. Flexible regulation of the temperature in sports spaces on the basis of the sport in question. 2. The ventilation of swimming halls should be adjusted in such a way that the humidity of the hall air would comply with the limit humidity curve determined by the quality of structures and the temperature of the outdoor air. 3. An ice skating hall is an establishment producing condensing energy from 8 to 9 months a year worth of approx. 100.000-150.000 Finnmarks. The development of the recovery of condensing energy has become more important. 4. The ventilation of ball games halls may account for over 50% of the energy consumption of the whole building. Therefore special attention should be paid to the optimatization of ventilation as a whole.

  13. Integrating knowledge-based systems into operations at the McMaster University FN tandem accelerator laboratory

    International Nuclear Information System (INIS)

    Poehlman, W.F.S.; Stark, J.W.

    1989-01-01

    The introduction of computer-based expertise in accelerator operations has resulted in the development of an Accelerator Operators' Companion which incorporates a knowledge-based front-end that is tuned to user operational expertise. The front-end also provides connections to traditional software packages such as database and spreadsheet programs. During work on the back-end, that is, real-time expert system control development, the knowledge engineering phase has revealed the importance of modifying expert procedures when a multitasking environment is involved

  14. Scanning vector Hall probe microscopy

    International Nuclear Information System (INIS)

    Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.

    2004-01-01

    We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K

  15. On Hall current fluid

    International Nuclear Information System (INIS)

    Shen, M.C.; Ebel, D.

    1987-01-01

    In this paper some new results concerning magnetohydrodynamic (MHD) equations with the Hall current (HC) term in the Ohm's law are presented. For the cylindrical pinch of a compressible HC fluid, it is found that for large time and long wave length the solution to the governing equations exhibits the behavior of solitons as in the case of an ideal MHD model. In some special cases, the HC model appears to be better posed. An open question is whether a simple toroidal equilibrium of an HC fluid with resistivity and viscosity exists. The answer to this question is affirmative if the prescribed velocity on the boundary has a small norm. Furthermore, the equilibrium is also linearly and nonlinearly stable

  16. Farm Hall: The Play

    Science.gov (United States)

    Cassidy, David C.

    2013-03-01

    It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.

  17. Laboratory and field testing of an accelerated bridge construction demonstration bridge : US Highway 6 bridge over Keg Creek.

    Science.gov (United States)

    2013-04-01

    The US Highway 6 Bridge over Keg Creek outside of Council Bluffs, Iowa is a demonstration bridge site chosen to put into practice : newly-developed Accelerated Bridge Construction (ABC) concepts. One of these new concepts is the use of prefabricated ...

  18. Numerate Intends to Join ATOM Consortium to Rapidly Accelerate Preclinical Drug Development | Frederick National Laboratory for Cancer Research

    Science.gov (United States)

    SAN FRANCISCO – Computational drug design company Numerate has signed a letter of intent to join an open consortium of scientists staffed from two U.S. national laboratories, industry, and academia working to transform drug discovery and developmen

  19. The fractional quantum Hall effect goes organic

    International Nuclear Information System (INIS)

    Smet, Jurgen

    2000-01-01

    Physicists have been fascinated by the behaviour of two-dimensional electron gases for the past two decades. All of these experiments were performed on inorganic semiconductor devices, most of them based on gallium arsenide. Indeed, until recently it was thought that the subtle effects that arise due to electron-electron interactions in these devices required levels of purity that could not be achieved in other material systems. However, Hendrik Schoen, Christian Kloc and Bertram Batlogg of Bell Laboratories in the US have now observed the fractional quantum Hall effect - the most dramatic signature of electron-electron interactions - in two organic semiconductors. (U.K.)

  20. Accelerating technology transfer from federal laboratories to the private sector by industrial R and D collaborations - A new business model

    Energy Technology Data Exchange (ETDEWEB)

    LOMBANA,CESAR A.; ROMIG JR.,ALTON D.; LINTON,JONATHAN D.; MARTINEZ,J. LEONARD

    2000-04-13

    Many important products and technologies were developed in federal laboratories and were driven initially by national needs and for federal applications. For example, the clean room technology that enhanced the growth of the semiconductor industry was developed at Sandia National Laboratories (SNL) decades ago. Similarly, advances in micro-electro-mechanical-systems (MEMS)--an important set of process technologies vital for product miniaturization--are occurring at SNL. Each of the more than 500 federal laboratories in the US, are sources of R and D that contributes to America's economic vitality, productivity growth and, technological innovation. However, only a fraction of the science and technology available at the federal laboratories is being utilized by industry. Also, federal laboratories have not been applying all the business development processes necessary to work effectively with industry in technology commercialization. This paper addresses important factors that federal laboratories, federal agencies, and industry must address to translate these under utilized technologies into profitable products in the industrial sector.

  1. Hall Effect Gyrators and Circulators

    Science.gov (United States)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  2. First electrons from the new 220 TW Frascati Laser for Acceleration and Multidisciplinary Experiments (FLAME) at Frascati National Laboratories (LNF)

    International Nuclear Information System (INIS)

    Levato, T.; Calvetti, M.; Anelli, F.; Batani, D.; Benocci, R.; Cacciotti, L.; Cecchetti, C.A.; Cerafogli, O.; Chimenti, P.; Clozza, A.; Drenska, N.; Esposito, A.; Faccini, R.; Fioravanti, S.; Gamucci, A.; Gatti, C.; Giulietti, A.; Giulietti, D.; Labate, L.; Lollo, V.

    2013-01-01

    A new era of laser based plasma accelerators is emerging following the commissioning of many high power laser facilities around the world. Extremely short (tens of fs) laser pulses with energy of multi-joules level are available at these newly built facilities. Here we describe the new 220 TW FLAME facility. In particular we discuss the laser system general layout, the main measurements on the laser pulse parameters, the underground target area. Finally we give an overview of the first results of the Self-Injection Test Experiment (SITE), obtained at a low laser energy. This initial low laser energy experimental campaign was necessary for the validation of the radio-protection shielding (Esposito, 2011 [1]) we discuss here. With respect to our preliminary configuration, with a pulse duration of 30 fs and a focusing optic of F/15, we discuss here the minimum laser energy requirements for electron acceleration and the forward transmitted optical radiation

  3. Topological Hall and spin Hall effects in disordered skyrmionic textures

    KAUST Repository

    Ndiaye, Papa Birame; Akosa, Collins Ashu; Manchon, Aurelien

    2017-01-01

    We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.

  4. Topological Hall and spin Hall effects in disordered skyrmionic textures

    KAUST Repository

    Ndiaye, Papa Birame

    2017-02-24

    We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.

  5. Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. Y.; Yang, G. [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. G., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. L. [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, R. M. [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Amsellem, E.; Kohn, A. [Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Yu, G. H., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-04-13

    Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.

  6. Performance of a Cylindrical Hall-Effect Thruster Using Permanent Magnets

    Science.gov (United States)

    Polzin, Kurt A.; Raitses, Y.; Merino, E.; Fisch, N. J.

    2009-01-01

    While annular Hall thrusters can operate at high efficiency at kW power levels, it is difficult to construct one that operates over a broad envelope from 1 kW down to 100 W while maintaining an efficiency of 45-55%. Scaling to low power while holding the main dimensionless parameters constant requires a decrease in the thruster channel size and an increase in the magnetic field strength. Increasing the magnetic field becomes technically challenging since the field can saturate the miniaturized inner components of the magnetic circuit and scaling down the magnetic circuit leaves very little room for magnetic pole pieces and heat shields. In addition, the central magnetic pole piece defining the interior wall of the annular channel can experience excessive heat loads in a miniaturized Hall thruster, with the temperature eventually exceeding the Curie temperature of the material and in extreme circumstances leading to accelerated erosion of the channel wall. An alternative approach is to employ a cylindrical Hall thruster (CHT) geometry. Laboratory model CHTs have operated at power levels ranging from 50 W up to 1 kW. These thrusters exhibit performance characteristics that are comparable to conventional, annular Hall thrusters of similar size. Compared to the annular Hall thruster, the CHTs insulator surface area to discharge chamber volume ratio is lower. Consequently, there is the potential for reduced wall losses in the channel of a CHT, and any reduction in wall losses should translate into lower channel heating rates and reduced erosion, making the CHT geometry promising for low-power applications. This potential for high performance in the low-power regime has served as the impetus for research and development efforts aimed at understanding and improving CHT performance. Recently, a 2.6 cm channel diameter permanent magnet CHT (shown in Fig. 1) was tested. This thruster has the promise of reduced power consumption over previous CHT iterations that employed

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-06

    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.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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.

  9. Anomalous Hall effect

    Science.gov (United States)

    Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.

    2010-04-01

    The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a

  10. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

    2010-01-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

  11. Gauge invariance and fractional quantized Hall effect

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.

    1984-01-01

    It is shown that gauge invariance arguments imply the possibility of fractional quantized Hall effect; the Hall conductance is accurately quantized to a rational value. The ground state of a system showing the fractional quantized Hall effect must be degenerate; the non-degenerate ground state can only produce the integral quantized Hall effect. 12 references

  12. "Hall mees" Linnateatris / Triin Sinissaar

    Index Scriptorium Estoniae

    Sinissaar, Triin

    1999-01-01

    Tallinn Linnateatri ja Raadioteatri ühislavastus "Hall mees" Gill Adamsi näidendi järgi, lavastaja Eero Spriit, osades Helene Vannari ja Väino Laes, kunstnik Kustav - Agu Püüman. Esietendus 22. okt

  13. Sheldon-Hall syndrome

    Directory of Open Access Journals (Sweden)

    Bamshad Michael J

    2009-03-01

    Full Text Available Abstract Sheldon-Hall syndrome (SHS is a rare multiple congenital contracture syndrome characterized by contractures of the distal joints of the limbs, triangular face, downslanting palpebral fissures, small mouth, and high arched palate. Epidemiological data for the prevalence of SHS are not available, but less than 100 cases have been reported in the literature. Other common clinical features of SHS include prominent nasolabial folds, high arched palate, attached earlobes, mild cervical webbing, short stature, severe camptodactyly, ulnar deviation, and vertical talus and/or talipes equinovarus. Typically, the contractures are most severe at birth and non-progressive. SHS is inherited in an autosomal dominant pattern but about half the cases are sporadic. Mutations in either MYH3, TNNI2, or TNNT3 have been found in about 50% of cases. These genes encode proteins of the contractile apparatus of fast twitch skeletal muscle fibers. The diagnosis of SHS is based on clinical criteria. Mutation analysis is useful to distinguish SHS from arthrogryposis syndromes with similar features (e.g. distal arthrogryposis 1 and Freeman-Sheldon syndrome. Prenatal diagnosis by ultrasonography is feasible at 18–24 weeks of gestation. If the family history is positive and the mutation is known in the family, prenatal molecular genetic diagnosis is possible. There is no specific therapy for SHS. However, patients benefit from early intervention with occupational and physical therapy, serial casting, and/or surgery. Life expectancy and cognitive abilities are normal.

  14. Laser Safety for the Experimental Halls at SLAC_s Linac Coherent Light Source (LCLS)

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Michael; Anthony, Perry; /SLAC; Barat, Ken; /LBL, Berkeley; Gilevich, Sasha; Hays, Greg; White, William E.; /SLAC

    2009-01-15

    The LCLS at the SLAC National Accelerator Laboratory will be the world's first source of an intense hard x-ray laser beam, generating x-rays with wavelengths of 1nm and pulse durations less than 100fs. The ultrafast x-ray pulses will be used in pump-probe experiments to take stop-motion pictures of atoms and molecules in motion, with pulses powerful enough to take diffraction images of single molecules, enabling scientists to elucidate fundamental processes of chemistry and biology. Ultrafast conventional lasers will be used as the pump. In 2009, LCLS will deliver beam to the Atomic Molecular and Optical (AMO) Experiment, located in one of 3 x-ray Hutches in the Near Experimental Hall (NEH). The NEH includes a centralized Laser Hall, containing up to three Class 4 laser systems, three x-ray Hutches for experiments and vacuum transport tubes for delivering laser beams to the Hutches. The main components of the NEH laser systems are a Ti:sapphire oscillator, a regen amplifier, green pump lasers for the oscillator and regen, a pulse compressor and a harmonics conversion unit. Laser safety considerations and controls for the ultrafast laser beams, multiple laser controlled areas, and user facility issues are discussed.

  15. Theory of spin Hall effect

    OpenAIRE

    Chudnovsky, Eugene M.

    2007-01-01

    An extension of Drude model is proposed that accounts for spin and spin-orbit interaction of charge carriers. Spin currents appear due to combined action of the external electric field, crystal field and scattering of charge carriers. The expression for spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, spin Hall conductivity $\\sigma_s$ and charge conductivity $\\sigma_c$ are related through $\\sigma_s = [2 \\pi \\hbar...

  16. Not your grandfather's concert hall

    Science.gov (United States)

    Cooper, Russell; Malenka, Richard; Griffith, Charles; Friedlander, Steven

    2004-05-01

    The opening of Judy and Arthur Zankel Hall on 12 September 2003, restores Andrew Carnegie's original 1891 concept of having three outstanding auditoriums of different sizes under one roof, and creates a 21st-century venue for music performance and education. With concerts ranging from early music to avant-garde multimedia productions, from jazz to world music, and from solo recitals to chamber music, Zankel Hall expands the breadth and depth of Carnegie Hall's offerings. It allows for the integration of programming across three halls with minifestivals tailored both to the size and strengths of each hall and to the artists and music to be performed. The new flexible space also provides Carnegie Hall with an education center equipped with advanced communications technology. This paper discusses the unique program planned for this facility and how the architects, theatre consultants, and acousticians developed a design that fulfilled the client's expectations and coordinated the construction of the facility under the floor of the main Isaac Stern Auditorium without having to cancel a single performance.

  17. Microgravity Emissions Laboratory (MEL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Microgravity Emissions Laboratory (MEL) utilizes a low-frequency acceleration measurement system for the characterization of rigid body inertial forces generated...

  18. Repurposing the Caltech Robinson Hall Coelostat

    Science.gov (United States)

    Treffers, Richard R.; Loisos, G.; Ubbelohde, M.; Douglas, S.; Martinez, M.

    2013-01-01

    We describe the repurposing of the historic coelostat atop Caltech’s Robinson Hall for building lighting, public education and scientific research. The coelostat was originally part of George Ellery Hale’s vision of the Astrophysical Laboratory on the Caltech campus in 1932. The coelostat, designed by Russell Porter, has a 36 inch diameter primary mirror a 30 inch diameter secondary mirror and provides a 24 inch un-vignetted beam of sunlight into the building. Although constructed in the 1930s, due to wartime pressures and other projects, it was used only briefly in the 1970s and never fully realized. Recently Robinson Hall has been fully renovated to house the Ronald and Maxine Linde Center for Global Environmental Science. The coelostat operation was modernized replacing the old motors and automating all the motions. Each morning, if the weather cooperates, the dome slit opens, the mirrors configured and sunlight pours into the building. The beam of sunlight is divided into three parts. One part goes into a refracting telescope which projects a ten inch diameter of the sun onto a ground glass screen visible to the public. A second fraction is distributed to fiber optic fixtures that illuminate some of the basement rooms. The final fraction goes into two laboratories where it is used in experiments monitoring trace constituents of our atmosphere and for solar catalysis experiments. The instrument as originally conceived required at least two human operators. Now it is fully automatic and doing real science

  19. Search for Evidence of Photoproduction of Higher Twist QCD Events at Experiment 683 at Fermi National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Traynor, Michael M. [Rice Univ., Houston, TX (United States)

    1996-01-01

    Experiment 683 at Fermilab Wide Band Photon Laboratory observed events via $\\gamma P \\to jets$ during the 1991-1992 fixed target run. The present analysis attempted to observe the higher-twist subprocess in QCD using that data to measure the $p_\\perp$ spectrum via a clustering algorithm tuned to optimize the distinctive topology of higher-twist events. Results indicate a substantial $k_\\perp$ promotion effect at lower $p_\\perp$ and a significant NLO contribution to the photoproduction.

  20. Transit-time instability in Hall thrusters

    International Nuclear Information System (INIS)

    Barral, Serge; Makowski, Karol; Peradzynski, Zbigniew; Dudeck, Michel

    2005-01-01

    Longitudinal waves characterized by a phase velocity of the order of the velocity of ions have been recurrently observed in Hall thruster experiments and simulations. The origin of this so-called ion transit-time instability is investigated with a simple one-dimensional fluid model of a Hall thruster discharge in which cold ions are accelerated between two electrodes within a quasineutral plasma. A short-wave asymptotics applied to linearized equations shows that plasma perturbations in such a device consist of quasineutral ion acoustic waves superimposed on a background standing wave generated by discharge current oscillations. Under adequate circumstances and, in particular, at high ionization levels, acoustic waves are amplified as they propagate, inducing strong perturbation of the ion density and velocity. Responding to the subsequent perturbation of the column resistivity, the discharge current generates a standing wave, the reflection of which sustains the generation of acoustic waves at the inlet boundary. A calculation of the frequency and growth rate of this resonance mechanism for a supersonic ion flow is proposed, which illustrates the influence of the ionization degree on their onset and the approximate scaling of the frequency with the ion transit time. Consistent with experimental reports, the traveling wave can be observed on plasma density and velocity perturbations, while the plasma potential ostensibly oscillates in phase along the discharge

  1. Numerical investigation of a Hall thruster plasma

    International Nuclear Information System (INIS)

    Roy, Subrata; Pandey, B.P.

    2002-01-01

    The dynamics of the Hall thruster is investigated numerically in the framework of a one-dimensional, multifluid macroscopic description of a partially ionized xenon plasma using finite element formulation. The model includes neutral dynamics, inelastic processes, and plasma-wall interaction. Owing to disparate temporal scales, ions and neutrals have been described by set of time-dependent equations, while electrons are considered in steady state. Based on the experimental observations, a third order polynomial in electron temperature is used to calculate ionization rate. The results show that in the acceleration channel the increase in the ion number density is related to the decrease in the neutral number density. The electron and ion velocity profiles are consistent with the imposed electric field. The electron temperature remains uniform for nearly two-thirds of the channel; then sharply increases to a peak before dropping slightly at the exit. This is consistent with the predicted electron gyration velocity distribution

  2. Chaotic waves in Hall thruster plasma

    International Nuclear Information System (INIS)

    Peradzynski, Zbigniew; Barral, S.; Kurzyna, J.; Makowski, K.; Dudeck, M.

    2006-01-01

    The set of hyperbolic equations of the fluid model describing the acceleration of plasma in a Hall thruster is analyzed. The characteristic feature of the flow is the existence of a trapped characteristic; i.e. there exists a characteristic line, which never intersects the boundary of the flow region in the thruster. To study the propagation of short wave perturbations, the approach of geometrical optics (like WKB) can be applied. This can be done in a linear as well as in a nonlinear version. The nonlinear version describes the waves of small but finite amplitude. As a result of such an approach one obtains so called transport equation, which are governing the wave amplitude. Due to the existence of trapped characteristics this transport equation appears to have chaotic (turbulent) solutions in both, linear and nonlinear versions

  3. Improvement of the low frequency oscillation model for Hall thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunsheng, E-mail: wangcs@hit.edu.cn; Wang, Huashan [Yanshan University, College of Vehicles and Energy, Qinhuangdao 066004, Hebei (China)

    2016-08-15

    The low frequency oscillation of the discharge current in Hall thrusters is a major aspect of these devices that requires further study. While the existing model captures the ionization mechanism of the low frequency oscillation, it unfortunately fails to express the dynamic characteristics of the ion acceleration. The analysis in this paper shows this is because of the simplification of the electron equation, which affects both the electric field distribution and the ion acceleration process. Additionally, the electron density equation is revised and a new model that is based on the physical properties of ion movement is proposed.

  4. The CLAS12 Torus Detector Magnet at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Luongo, Cesar [Jefferson Lab; Ballard, Joshua [Jefferson Lab; Biallas, George [Jefferson Lab; Elouadrhiri, Latifa [Jefferson Lab; Fair, Ruben [Jefferson Lab; Ghoshal, Probir [Jefferson Lab; Kashy, Dave [Jefferson Lab; Legg, Robert [Jefferson Lab; Pastor, Orlando [Jefferson Lab; Rajput-Ghoshal, Renuka [Jefferson Lab; Rode, Claus [Jefferson Lab; Wiseman, Mark [Jefferson Lab; Young, Glenn [Jefferson Lab; Elementi, Luciano [Fermilab; Krave, Steven [Fermilab; Makarov, Alexander [Fermilab; Nobrega, Fred [Fermilab; Velev, George [Fermilab

    2015-12-17

    The CLAS12 Torus is a toroidal superconducting magnet, which is part of the detector for the 12-GeV accelerator upgrade at Jefferson Laboratory (JLab). The coils were wound/fabricated by Fermilab, with JLab responsible for all other parts of the project scope, including design, integration, cryostating the individual coils, installation, cryogenics, I&C, etc. This paper provides an overview of the CLAS12 Torus magnet features and serves as a status report of its installation in the experimental hall. Completion and commissioning of the magnet is expected in 2016.

  5. Tests of an environmental and personnel safe cleaning process for Brookhaven National Laboratory accelerator and storage ring components

    International Nuclear Information System (INIS)

    Foerster, C.L.; Lanni, C.; Lee, R.; Mitchell, G.; Quade, W.

    1997-01-01

    A large measure of the successful operation of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL) for over a decade can be attributed to the cleaning of its ultrahigh vacuum (UHV) components during and after construction. A new UHV cleaning process, which has to be environmentally and personnel safe, is needed to replace the harsh, unfriendly process which is still in use. Dow Advanced Cleaning Systems was contracted to develop a replacement process without the use of harsh chemicals and which must clean vacuum surfaces as well as the existing process. Acceptance of the replacement process was primarily based on photon stimulated desorption (PSD) measurements of beam tube samples run on NSLS beam line U10B. One meter long beam tube samples were fabricated from aluminum, 304 stainless steel, and oxygen-free copper. Initially, coupon samples were cleaned and passed preliminary testing for the proposed process. Next, beam tube samples of each material were cleaned, and the PSD measured on beam line U10B using white light with a critical energy of 487 eV. Prior to cleaning, the samples were contaminated with a mixture of cutting oils, lubricants, vacuum oils, and vacuum grease. The contaminated samples were then baked. Samples of each material were also cleaned with the existing process after the same preparation. Beam tube samples were exposed to between 10 22 and 10 23 photons per meter for a PSD measurement. Desorption yields for H 2 , CO, CO 2 , CH 4 , and H 2 O are reported for both the existing cleaning and for the replacement cleaning process. Preliminary data, residual gas scans, and PSD results are given and discussed. The new process is also compared with new cleaning methods developed in other laboratories. After modification, the new UHV cleaning process was accepted by BNL

  6. Target laboratory

    International Nuclear Information System (INIS)

    Ephraim, D.C.; Pednekar, A.R.

    1993-01-01

    A target laboratory to make stripper foils for the accelerator and various targets for use in the experiments is set up in the pelletron accelerator facility. The facilities available in the laboratory are: (1) D.C. glow discharge setup, (2) carbon arc set up, and (3) vacuum evaporation set up (resistance heating), electron beam source, rolling mill - all for target preparation. They are described. Centrifugal deposition technique is used for target preparation. (author). 3 figs

  7. ac spin-Hall effect

    International Nuclear Information System (INIS)

    Entin-Wohlman, O.

    2005-01-01

    Full Text:The spin-Hall effect is described. The Rashba and Dresselhaus spin-orbit interactions are both shown to yield the low temperature spin-Hall effect for strongly localized electrons coupled to phonons. A frequency-dependent electric field E(ω) generates a spin-polarization current, normal to E, due to interference of hopping paths. At zero temperature the corresponding spin-Hall conductivity is real and is proportional to ω 2 . At non-zero temperatures the coupling to the phonons yields an imaginary term proportional to ω. The interference also yields persistent spin currents at thermal equilibrium, at E = 0. The contributions from the Dresselhaus and Rashba interactions to the interference oppose each other

  8. Kr II laser-induced fluorescence for measuring plasma acceleration.

    Science.gov (United States)

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

    2012-10-01

    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.

  9. Status report on the heavy ion accelerator facility at TIFR

    International Nuclear Information System (INIS)

    Srinivasan, B.

    2006-01-01

    The 14 UD Pelletron Accelerator has been delivering heavy ion beams for experimental programs in Nuclear Physics and other fields. During the year beam was delivered for 72% of the time remaining after completion of certain infrastructural activities. Various developmental activities were also taken up in the laboratories associated with the Pelletron. The Superconducting Linac being constructed as a booster for the heavy ion beams from the Pelletron is in an advanced state of completion. Five of the seven cryostat modules have been assembled and tested with beam from the Pelletron. The last two remaining modules are being assembled. A new experimental beam hall has been constructed for utilization of the accelerated beam from the Linac and beam transport to one of the target areas has been carried out. (author)

  10. Hurricane Isabel gives accelerators a severe test

    International Nuclear Information System (INIS)

    Swapan Chattopadhyay

    2004-01-01

    Hurricane Isabel was at category five--the most violent on the Saffir-Simpson scale of hurricane strength--when it began threatening the central Atlantic seaboard of the US. Over the course of several days, precautions against the extreme weather conditions were taken across the Jefferson Lab site in south-east Virginia. On 18 September 2003, when Isabel struck North Carolina's Outer Banks and moved northward, directly across the region around the laboratory, the storm was still quite destructive, albeit considerably reduced in strength. The flood surge and trees felled by wind substantially damaged or even devastated buildings and homes, including many belonging to Jefferson Lab staff members. For the laboratory itself, Isabel delivered an unplanned and severe challenge in another form: a power outage that lasted nearly three-and-a-half days, and which severely tested the robustness of Jefferson Lab's two superconducting machines, the Continuous Electron Beam Accelerator Facility (CEBAF) and the superconducting radiofrequency ''driver'' accelerator of the laboratory's free-electron laser. Robustness matters greatly for science at a time when microwave superconducting linear accelerators (linacs) are not only being considered, but in some cases already being built for projects such as neutron sources, rare-isotope accelerators, innovative light sources and TeV-scale electron-positron linear colliders. Hurricane Isabel interrupted a several-week-long maintenance shutdown of CEBAF, which serves nuclear and particle physics and represents the world's pioneering large-scale implementation of superconducting radiofrequency (SRF) technology. The racetrack-shaped machine is actually a pair of 500-600 MeV SRF linacs interconnected by recirculation arc beamlines. CEBAF delivers simultaneous beams at up to 6 GeV to three experimental halls. An imminent upgrade will double the energy to 12 GeV and add an extra hall for ''quark confinement'' studies. On a smaller scale

  11. CERN Accelerator School

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-01-15

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

  12. CERN Accelerator School

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

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

  13. ATLAS Assembly Hall Open Day

    CERN Multimedia

    Patrice Loiez

    2004-01-01

    To mark the 50th Anniversary of the founding of CERN, a day of tours, displays and presentations was held in October 2004. The assembly halls for the experiments that were waiting to be installed on the LHC, such as ATLAS shown here, were transformed into display areas and cafés.

  14. Universal intrinsic spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, J.; Culcer, D.; Sinitsyn, N. A.; Niu, Q.; Jungwirth, Tomáš; MacDonald, A. H.

    2004-01-01

    Roč. 92, č. 12 (2004), 126603/1-126603/4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912 Institutional research plan: CEZ:AV0Z1010914 Keywords : semiconductor quantum wells * spin-orbit interaction * spin Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.218, year: 2004

  15. Spin Hall effect for anyons

    International Nuclear Information System (INIS)

    Dhar, S.; Basu, B.; Ghosh, Subir

    2007-01-01

    We explain the intrinsic spin Hall effect from generic anyon dynamics in the presence of external electromagnetic field. The free anyon is represented as a spinning particle with an underlying non-commutative configuration space. The Berry curvature plays a major role in the analysis

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

    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

  17. Parametric studies of the Hall Thruster at Soreq

    International Nuclear Information System (INIS)

    Ashkenazy, J.; Rattses, Y.; Appelbaum, G.

    1997-01-01

    An electric propulsion program was initiated at Soreq a few years ago, aiming at the research and development of advanced Hall thrusters for various space applications. The Hall thruster accelerates a plasma jet by an axial electric field and an applied radial magnetic field in an annular ceramic channel. A relatively large current density (> 0.1 A/cm 2 ) can be obtained, since the acceleration mechanism is not limited by space charge effects. Such a device can be used as a small rocket engine onboard spacecraft with the advantage of a large jet velocity compared with conventional rocket engines (10,000-30,000 m/s vs. 2,000-4,800 m/s). An experimental Hall thruster was constructed at Soreq and operated under a broad range of operating conditions and under various configurational variations. Electrical, magnetic and plasma diagnostics, as well as accurate thrust and gas flow rate measurements, have been used to investigate the dependence of thruster behavior on the applied voltage, gas flow rate, magnetic field, channel geometry and wall material. Representative results highlighting the major findings of the studies conducted so far are presented

  18. Commissioning and Testing the 1970's Era LASS Solenoid Magnet in JLab's Hall D

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, Joshua T. [Jefferson Lab, Newport News, VA; Biallas, George H. [Jefferson Lab, Newport News, VA; Brown, G.; Butler, David E. [Jefferson Lab, Newport News, VA; Carstens, Thomas J. [Jefferson Lab, Newport News, VA; Chudakov, Eugene A. [Jefferson Lab, Newport News, VA; Creel, Jonathan D. [Jefferson Lab, Newport News, VA; Egiyan, Hovanes [Jefferson Lab, Newport News, VA; Martin, F.; Qiang, Yi [Jefferson Lab, Newport News, VA; Smith, Elton S. [Jefferson Lab, Newport News, VA; Stevens, Mark A. [Jefferson Lab, Newport News, VA; Spiegel, Scot L. [Jefferson Lab, Newport News, VA; Whitlatch, Timothy E. [Jefferson Lab, Newport News, VA; Wolin, Elliott J. [Carnegie Mellon University , Pittsburgh, PA; Ghoshal, Probir K. [Jefferson Lab, Newport News, VA

    2015-06-01

    JLab refurbished and reconfigured the LASS1, 1.85m bore Solenoid and installed it as the principal analysis magnet for nuclear physics in the newly constructed, Hall D at Jefferson Lab. The magnet contains four superconducting coils within an iron yoke. The magnet was built in the early1970's at Stanford Linear Accelerator Center and used a second time at Los Alamos National Laboratory. The coils were extensively refurbished and individually tested by JLab. A new Cryogenic Distribution Box provides cryogens and their control valving, current distribution bus, and instrumentation pass-through. A repurposed CTI 2800 refrigerator system and new transfer line complete the system. We describe the re-configuration, the process and problems of re-commissioning the magnet and the results of testing the completed magnet.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-29

    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

  1. Magnetic field deformation due to electron drift in a Hall thruster

    Directory of Open Access Journals (Sweden)

    Han Liang

    2017-01-01

    Full Text Available The strength and shape of the magnetic field are the core factors in the design of the Hall thruster. However, Hall current can affect the distribution of static magnetic field. In this paper, the Particle-In-Cell (PIC method is used to obtain the distribution of Hall current in the discharge channel. The Hall current is separated into a direct and an alternating part to calculate the induced magnetic field using Finite Element Method Magnetics (FEMM. The results show that the direct Hall current decreases the magnetic field strength in the acceleration region and also changes the shape of the magnetic field. The maximum reduction in radial magnetic field strength in the exit plane is 10.8 G for an anode flow rate of 15 mg/s and the maximum angle change of the magnetic field line is close to 3° in the acceleration region. The alternating Hall current induces an oscillating magnetic field in the whole discharge channel. The actual magnetic deformation is shown to contain these two parts.

  2. Detection and Solution of Indoor Air Quality Problems in a Danish Town Hall

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik; Brohus, Henrik

    In connection with the research programme "Healthy Buildings", a building with indoor air quality problems was selected for further investigations. A Danish town hall was chosen because of many complaints over several years. A full-scale mock-up of a typical town hall office was built...... in the climate laboratory. A new heating and ventilating system and a new control strategy were chosen and implemented into the town hall. It was found that air supply upwards along a window may make it nearly impossible to achieve comfort and a good air quality the year round without full-scale measurements....

  3. Accelerators at school

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

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

  4. Accelerators at school

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-06-15

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

  5. 1000 Hours of Testing Completed on 10-kW Hall Thruster

    Science.gov (United States)

    Mason, Lee S.

    2001-01-01

    Between the months of April and August 2000, a 10-kW Hall effect thruster, designated T- 220, was subjected to a 1000-hr life test evaluation. Hall effect thrusters are propulsion devices that electrostatically accelerate xenon ions to produce thrust. Hall effect propulsion has been in development for many years, and low-power devices (1.35 kW) have been used in space for satellite orbit maintenance. The T-220, shown in the photo, produces sufficient thrust to enable efficient orbital transfers, saving hundreds of kilograms in propellant over conventional chemical propulsion systems. This test is the longest operation ever achieved on a high-power Hall thruster (greater than 4.5 kW) and is a key milestone leading to the use of this technology for future NASA, commercial, and military missions.

  6. Particle-in-cell simulations of Hall plasma thrusters

    Science.gov (United States)

    Miranda, Rodrigo; Ferreira, Jose Leonardo; Martins, Alexandre

    2016-07-01

    Hall plasma thrusters can be modelled using particle-in-cell (PIC) simulations. In these simulations, the plasma is described by a set of equations which represent a coupled system of charged particles and electromagnetic fields. The fields are computed using a spatial grid (i.e., a discretization in space), whereas the particles can move continuously in space. Briefly, the particle and fields dynamics are computed as follows. First, forces due to electric and magnetic fields are employed to calculate the velocities and positions of particles. Next, the velocities and positions of particles are used to compute the charge and current densities at discrete positions in space. Finally, these densities are used to solve the electromagnetic field equations in the grid, which are interpolated at the position of the particles to obtain the acting forces, and restart this cycle. We will present numerical simulations using software for PIC simulations to study turbulence, wave and instabilities that arise in Hall plasma thrusters. We have sucessfully reproduced a numerical simulation of a SPT-100 Hall thruster using a two-dimensional (2D) model. In addition, we are developing a 2D model of a cylindrical Hall thruster. The results of these simulations will contribute to improve the performance of plasma thrusters to be used in Cubesats satellites currenty in development at the Plasma Laboratory at University of Brasília.

  7. Hall Thruster Thermal Modeling and Test Data Correlation

    Science.gov (United States)

    Myers, James; Kamhawi, Hani; Yim, John; Clayman, Lauren

    2016-01-01

    The life of Hall Effect thrusters are primarily limited by plasma erosion and thermal related failures. NASA Glenn Research Center (GRC) in cooperation with the Jet Propulsion Laboratory (JPL) have recently completed development of a Hall thruster with specific emphasis to mitigate these limitations. Extending the operational life of Hall thursters makes them more suitable for some of NASA's longer duration interplanetary missions. This paper documents the thermal model development, refinement and correlation of results with thruster test data. Correlation was achieved by minimizing uncertainties in model input and recognizing the relevant parameters for effective model tuning. Throughout the thruster design phase the model was used to evaluate design options and systematically reduce component temperatures. Hall thrusters are inherently complex assemblies of high temperature components relying on internal conduction and external radiation for heat dispersion and rejection. System solutions are necessary in most cases to fully assess the benefits and/or consequences of any potential design change. Thermal model correlation is critical since thruster operational parameters can push some components/materials beyond their temperature limits. This thruster incorporates a state-of-the-art magnetic shielding system to reduce plasma erosion and to a lesser extend power/heat deposition. Additionally a comprehensive thermal design strategy was employed to reduce temperatures of critical thruster components (primarily the magnet coils and the discharge channel). Long term wear testing is currently underway to assess the effectiveness of these systems and consequently thruster longevity.

  8. Hall effect in noncommutative coordinates

    International Nuclear Information System (INIS)

    Dayi, Oemer F.; Jellal, Ahmed

    2002-01-01

    We consider electrons in uniform external magnetic and electric fields which move on a plane whose coordinates are noncommuting. Spectrum and eigenfunctions of the related Hamiltonian are obtained. We derive the electric current whose expectation value gives the Hall effect in terms of an effective magnetic field. We present a receipt to find the action which can be utilized in path integrals for noncommuting coordinates. In terms of this action we calculate the related Aharonov-Bohm phase and show that it also yields the same effective magnetic field. When magnetic field is strong enough this phase becomes independent of magnetic field. Measurement of it may give some hints on spatial noncommutativity. The noncommutativity parameter θ can be tuned such that electrons moving in noncommutative coordinates are interpreted as either leading to the fractional quantum Hall effect or composite fermions in the usual coordinates

  9. General vibration monitoring: Experimental hall

    International Nuclear Information System (INIS)

    Jendrzejczyk, J.A.; Wambsganss, M.W.; Smith, R.K.

    1993-01-01

    The reported vibration data were generated from measurements made on the experimental hall floor on December 2, 1992. At the time of the measurements, the ESRF hydrolevel was set-up in the Early Assembly Area (EAA) of the experimental hall and was being used to measure static displacement (settlement) of the floor. The vibration measurement area was on and adjacent to the EAA, in the vicinity of the ESRF hydrolevel test which was in progress. This report summarizes the objectives, instrumentation, measurement locations, observations, and conclusions, and provides selected results in the form of RMS vs. time plots, and power spectral densities from which frequency information can be derived. Measured response amplitudes were within the vibration criteria established for the APS

  10. Scanning vector Hall probe microscope

    Czech Academy of Sciences Publication Activity Database

    Fedor, J.; Cambel, V.; Gregušová, D.; Hanzelka, Pavel; Dérer, J.; Volko, J.

    2003-01-01

    Roč. 74, č. 12 (2003), s. 5105 - 5110 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z2065902 Keywords : VHPM * Hall sensor * Helium cryostat Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.343, year: 2003 http://web. ebscohost .com/ehost/pdf?vid=8&hid=115&sid=a7c0555a-21f4-4932-b1c6-a308ac4dd50b%40sessionmgr2

  11. Accelerating complex for basic researches in the nuclear physics

    NARCIS (Netherlands)

    Dovbnya, A.N.; Guk, I.S.; Kononenko, S.G.; Peev, F.A.; Tarasenko, A.S.; Botman, J.I.M.

    2009-01-01

    In 2003 in NSC KIPT was begun the work on development the project of accelerator, base facility IHEPNP NSC KIPT electron recirculator SALO. The accelerator will be disposed in target hall of accelerator LU 2000 complex. It is projected first of all as facility for basic researches in the field of

  12. Test Results of a 200 W Class Hall Thruster

    Science.gov (United States)

    Jacobson, David; Jankovsky, Robert S.

    1999-01-01

    The performance of a 200 W class Hall thruster was evaluated. Performance measurements were taken at power levels between 90 W and 250 W. At the nominal 200 W design point, the measured thrust was 11.3 mN. and the specific impulse was 1170 s excluding cathode flow in the calculation. A laboratory model 3 mm diameter hollow cathode was used for all testing. The engine was operated on laboratory power supplies in addition to a breadboard power processing unit fabricated from commercially available DC to DC converters.

  13. L'effet Hall Quantique

    Science.gov (United States)

    Samson, Thomas

    Nous proposons une methode permettant d'obtenir une expression pour la conductivite de Hall de structures electroniques bidimensionnelles et nous examinons celle -ci a la limite d'une temperature nulle dans le but de verifier l'effet Hall quantique. Nous allons nous interesser essentiellement a l'effet Hall quantique entier et aux effets fractionnaires inferieurs a un. Le systeme considere est forme d'un gaz d'electrons en interaction faible avec les impuretes de l'echantillon. Le modele du gaz d'electrons consiste en un gaz bidimensionnel d'electrons sans spin expose perpendiculairement a un champ magnetique uniforme. Ce dernier est decrit par le potentiel vecteur vec{rm A} defini dans la jauge de Dingle ou jauge symetrique. Conformement au formalisme de la seconde quantification, l'hamiltonien de ce gaz est represente dans la base des etats a un-corps de Dingle |n,m> et exprime ainsi en terme des operateurs de creation et d'annihilation correspondants a_sp{ rm n m}{dag} et a _{rm n m}. Nous supposons de plus que les electrons du niveau fondamental de Dingle interagissent entre eux via le potentiel coulombien. La methode utilisee fait appel a une equation mai tresse a N-corps, de nature quantique et statistique, et verifiant le second principe de la thermodynamique. A partir de celle-ci, nous obtenons un systeme d'equations differentielles appele hierarchie d'equations quantique dont la resolution nous permet de determiner une equation a un-corps, dite de Boltzmann quantique, et dictant l'evolution de la moyenne statistique de l'operateur non-diagonal a _sp{rm n m}{dag } a_{rm n}, _{rm m}, sous l'action du champ electrique applique vec{rm E}(t). C'est sa solution Tr(p(t) a _sp{rm n m}{dag} a_{rm n},_ {rm m}), qui definit la relation de convolution entre la densite courant de Hall vec{rm J}_{rm H }(t) et le champ electrique vec {rm E}(t) dont la transformee de Laplace-Fourier du noyau nous fournit l'expression de la conductivite de Hall desiree. Pour une valeur de

  14. Remediation of old ecological burdens in UJV Rez, a. s. - alpha hall

    International Nuclear Information System (INIS)

    Posvar, R.; Holubova, D.; Svoboda, K.

    2018-01-01

    Two research reactors, hot and semi-hot chambers, laboratories, radioactive waste disposal facilities and many other technologies are in operation at the Nuclear Power Plant site. As a result of these activities a significant amount of radioactive wastes, contaminated and irradiated materials, equipment and construction structures for disposal and disposal were created in the Nuclear Research Institute. These old radioactive loads can be characterized as ecological liabilities incurred prior to the privatization of the Nuclear Power Plant. The implementation of the rehabilitation works of the Nuclear Power Plant continued and continues to be successful. The results of regular monitoring confirm that there is no release of radioactive substances into the environment. This work focuses on the elimination of the alpha hall workplace in facility 250 - Radiochemistry. The Alpha Hall has been used to research and develop chemical separations and analyzes for uranium and transuranium elements in the fuel cycle chemistry (especially the separation and determination of plutonium, america, neptunium, curium and uranium). In 2015, this workplace was influenced a combination of age degradation with radiation degradation of one of the plastic packages to leakage of the Am and Pu compound. The contamination was local and within the limits of non-interference levels. The health of workers and the environment were not compromised. However, this event has led to an acceleration of the redevelopment of the workplace, which took place between 2016 and 2017. For this purpose, a working procedure was developed which regulates the way of remedial work, including the solidification of the most risky materials. (authors)

  15. RF linear accelerators

    CERN Document Server

    Wangler, Thomas P

    2008-01-01

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

  16. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun

    2015-01-08

    The spin Hall and its inverse effects, driven by the spin orbit interaction, provide an interconversion mechanism between spin and charge currents. Since the spin Hall effect generates and manipulates spin current electrically, to achieve a large effect is becoming an important topic in both academia and industries. So far, materials with heavy elements carrying a strong spin orbit interaction, provide the only option. We propose here a new mechanism, using the surface roughness in ultrathin films, to enhance the spin Hall effect without heavy elements. Our analysis based on Cu and Al thin films suggests that surface roughness is capable of driving a spin Hall angle that is comparable to that in bulk Au. We also demonstrate that the spin Hall effect induced by surface roughness subscribes only to the side-jump contribution but not the skew scattering. The paradigm proposed in this paper provides the second, not if only, alternative to generate a sizable spin Hall effect.

  17. Tunneling Anomalous and Spin Hall Effects.

    Science.gov (United States)

    Matos-Abiague, A; Fabian, J

    2015-07-31

    We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems.

  18. Laboratories for Teaching of Mathematical Subjects

    Science.gov (United States)

    Berežný, Štefan

    2017-01-01

    We have adapted our two laboratories at our department based on our research results, which were presented at the conference CADGME 2014 in Halle and published in the journal. In this article we describe the hardware and software structure of the Laboratory 1: LabIT4KT-1: Laboratory of Computer Modelling and the Laboratory 2: LabIT4KT-2:…

  19. Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu

    2015-09-16

    We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

  20. Tearing mode dynamics and sawtooth oscillation in Hall-MHD

    Science.gov (United States)

    Ma, Zhiwei; Zhang, Wei; Wang, Sheng

    2017-10-01

    Tearing mode instability is one of the most important dynamic processes in space and laboratory plasmas. Hall effects, resulted from the decoupling of electron and ion motions, could cause the fast development and perturbation structure rotation of the tearing mode and become non-negligible. We independently developed high accuracy nonlinear MHD code (CLT) to study Hall effects on the dynamic evolution of tearing modes with Tokamak geometries. It is found that the rotation frequency of the mode in the electron diamagnetic direction is in a good agreement with analytical prediction. The linear growth rate increases with increase of the ion inertial length, which is contradictory to analytical solution in the slab geometry. We further find that the self-consistently generated rotation largely alters the dynamic behavior of the double tearing mode and the sawtooth oscillation. National Magnetic Confinement Fusion Science Program of China under Grant No. 2013GB104004 and 2013GB111004.

  1. Status of the MIT-Bates South Hall Ring commissioning

    International Nuclear Information System (INIS)

    Flanz, J.B.; Jacobs, K.D.; McAllister, B.; Averill, R.; Bradley, S.; Carter, A.; Dow, K.; Farkondeh, M.; Ihloff, E.; Kowalski, S.

    1993-01-01

    The MIT-Bates South Hall Ring construction project is now nearly complete. At this time the Energy Compression System, the SHR Injection Line and the South Hall Ring itself are complete. The SHR Extraction Line is complete but has not been connected to the ring. Commissioning with beam of the completed beam lines has been started. The MIT-Bates South Hall Ring (SHR) is an electron storage ring used with the 1 GeV Bates electron accelerator to increase the effective duty factor and luminosity. A beam can be stored for use with an internal target, thus allowing for high duty factor, high luminosity experiments. External beams with high duty factor can be obtained using resonant extraction. The new systems associated with the SHR include the Energy Compression System (ECS), the Injection line, and the Extraction line. The authors have commissioned the ECS, the new injection line and the SHR without RF. This includes transporting beam, measuring beam phase space parameters using critical injection elements including a high voltage electrostatic septum, a fast beam kicker, and storing a beam in the SHR

  2. Anomalous Hall effect in polycrystalline Ni films

    KAUST Repository

    Guo, Zaibing

    2012-02-01

    We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.

  3. Beams at U.S. high energy physics laboratories

    International Nuclear Information System (INIS)

    1976-06-01

    Tables are given of beam characteristics for particle accelerators at Argonne National Laboratory, Brookhaven National Laboratory, Cornell University, Fermi National Accelerator Laboratory, and the Stanford Linear Accelerator Center. Characteristics given include energy, momentum, and flux

  4. 75 FR 7467 - Gary E. Hall and Rita C. Hall; Notice of Application Accepted for Filing With the Commision...

    Science.gov (United States)

    2010-02-19

    ... Rita C. Hall; Notice of Application Accepted for Filing With the Commision, Soliciting Motions To.... Project No.: 13652-000. c. Date filed: January 11, 2010. d. Applicant: Gary E. Hall and Rita C. Hall. e... Policies Act of 1978, 16 U.S.C. 2705, 2708. h. Applicant Contact: Mr. Gary E. Hall and Ms. Rita C. Hall, P...

  5. Nondestructive hall coefficient measurements using ACPD techniques

    Science.gov (United States)

    Velicheti, Dheeraj; Nagy, Peter B.; Hassan, Waled

    2018-04-01

    Hall coefficient measurements offer great opportunities as well as major challenges for nondestructive materials characterization. The Hall effect is produced by the magnetic Lorentz force acting on moving charge carriers in the presence of an applied magnetic field. The magnetic perturbation gives rise to a Hall current that is normal to the conduction current but does not directly perturb the electric potential distribution. Therefore, Hall coefficient measurements usually exploit the so-called transverse galvanomagnetic potential drop effect that arises when the Hall current is intercepted by the boundaries of the specimen and thereby produce a measurable potential drop. In contrast, no Hall potential is produced in a large plate in the presence of a uniform normal field at quasi-static low frequencies. In other words, conventional Hall coefficient measurements are inherently destructive since they require cutting the material under tests. This study investigated the feasibility of using alternating current potential drop (ACPD) techniques for nondestructive Hall coefficient measurements in plates. Specifically, the directional four-point square-electrode configuration is investigated with superimposed external magnetic field. Two methods are suggested to make Hall coefficient measurements in large plates without destructive machining. At low frequencies, constraining the bias magnetic field can replace constraining the dimensions of the specimen, which is inherently destructive. For example, when a cylindrical permanent magnet is used to provide the bias magnetic field, the peak Hall voltage is produced when the diameter of the magnet is equal to the diagonal of the square ACPD probe. Although this method is less effective than cutting the specimen to a finite size, the loss of sensitivity is less than one order of magnitude even at very low frequencies. In contrast, at sufficiently high inspection frequencies the magnetic field of the Hall current induces a

  6. Gran Sasso, laboratori fermi per inquinamento

    CERN Multimedia

    Arachi, Alessandra

    2003-01-01

    An experimental hall at the Gran Sasso laboratory has been closed by the Courts after a river was found contaminated. The institute decided to close all the installations in order to protect the health of citizens (1 page)

  7. Superconducting Radiofrequency (SRF) Acceleration Technology

    Data.gov (United States)

    Federal Laboratory Consortium — SRF cavities enable accelerators to increase particle beam energy levels while minimizing the use of electrical power by all but eliminating electrical resistance....

  8. Japan Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

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

  9. Accelerator shielding benchmark problems

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  10. Japan Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-11-15

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

  11. Santa Fe Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

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

  12. Quantum Hall effect in quantum electrodynamics

    International Nuclear Information System (INIS)

    Penin, Alexander A.

    2009-01-01

    We consider the quantum Hall effect in quantum electrodynamics and find a deviation from the quantum-mechanical prediction for the Hall conductivity due to radiative antiscreening of electric charge in an external magnetic field. A weak dependence of the universal von Klitzing constant on the magnetic field strength, which can possibly be observed in a dedicated experiment, is predicted

  13. Hall devices improve electric motor efficiency

    Science.gov (United States)

    Haeussermann, W.

    1979-01-01

    Efficiency of electric motors and generators is reduced by radial magnetic forces created by symmetric fields within device. Forces are sensed and counteracted by Hall devices on excitation or control windings. Hall generators directly measure and provide compensating control of anu asymmetry, eliminating additional measurements needed for calibration feedback control loop.

  14. Higher fractions theory of fractional hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.; Popov, V.N.

    1985-07-01

    A theory of fractional quantum Hall effect is generalized to higher fractions. N-particle model interaction is used and the gap is expressed through n-particles wave function. The excitation spectrum in general and the mean field critical behaviour are determined. The Hall conductivity is calculated from first principles. (author)

  15. Industrial Application of Accelerators

    CERN Multimedia

    CERN. Geneva

    2017-01-01

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

  16. Industrial Application of Accelerators

    CERN Multimedia

    CERN. Geneva

    2017-01-01

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

  17. Report of experimental hall subworking group

    International Nuclear Information System (INIS)

    Miyake, K.; Ohama, T.; Takahashi, K.

    1982-01-01

    The general plan of constructing the TRISTAN e + e - colliding beam experimental halls may be divided into two parts. The first step is to construct two test-experimental halls associated with the 6.5 GeV x 6.5 GeV e + e - accumulator ring, and the second step is to build four experimental halls at the 30 GeV x 30 GeV e + e - TRISTAN main ring. At this workshop, extensive discussions on the detailed design of the four main ring experimental halls have been made. Four experimental areas will be built at the main ring, and two test-experimental halls at the accumulating ring. Among the four areas at the main ring, two will be used for electron-proton possible as well as electron-positron colliding beam experiment. The other two will be used exclusively for e + e - colliding experiments. Only a preliminary design has been made for these four experimental areas. A tentative plan of a larger experimental hall includes a counting and data processing room, a utility room, and a radiation safety control room. Two smaller halls have simpler structure. The figures of the experimental halls are presented. The two test-experimental halls at the accumulator ring will be used to test the detectors for e + e - colliding experiments before the final installation. The utility rooms designed for the halls are used to supply coolant and electric power of superconducting magnets. At the workshop, various ideas concerning the preliminary plan are presented. (Kato, T.)

  18. Analysis of seasonal strain measurements in asphalt materials under accelerated pavement testing and comparing field performance and laboratory measured binder tension properties : technical summary report.

    Science.gov (United States)

    2009-06-01

    Since 1996, the Louisiana Department of Transportation and Development (LADOTD) has : utilized the Louisiana Transportation and Research Centers (LTRCs) Accelerated Loading : Facility (ALF) at the Pavement Research Facility to determine the eff...

  19. The quantum Hall effect helicity

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Keshav N., E-mail: keshav1001@yahoo.com [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); School of Physics, University of Hyderabad, Hyderabad 500046 (India)

    2015-04-16

    The quantum Hall effect in semiconductor heterostructures is explained by two signs in the angular momentum j=l±s and g=(2j+1)/(2l+1) along with the Landau factor (n+1/2). These modifications in the existing theories explain all of the fractional charges. The helicity which is the sign of the product of the linear momentum with the spin p.s plays an important role for the understanding of the data at high magnetic fields. In particular it is found that particles with positive sign in the spin move in one direction and those with negative sign move in another direction which explains the up and down stream motion of the particles.

  20. Stuart Hall: An Organic Intellectual

    Directory of Open Access Journals (Sweden)

    Johanna Fernández Castro

    2017-01-01

    Full Text Available Stuart Hall (3 February 1932 – 10 February 2014 is acknowledged as one of the founding figures of British Cultural Studies. His extensive academic work on topics such as race, ethnicity and identity reflects his own position as a diasporic intellectual. His contribution to the study of popular culture is determined by the importance of his political character in every social act, his non-deterministic view of Marxism, and is especially determined by his insistence on playing an active role beyond academia in order to contribute to the transformation of hegemonic structures. The following biography aims to give a focused view of his personal history and its direct influence on his key theoretical reflections.

  1. The fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Stormer, H.L.

    1988-01-01

    The fractional quantum Hall effect (FQHE), is the manifestation of a new, highly correlated, many-particle ground state that forms in a two-dimensional electron system at low temperatures and in high magnetic fields. It is an example of the new physics that has grown out of the tremendous recent advances in semiconductor material science, which has provided us with high-quality, lower-dimensional carrier systems. The novel electronic state exposes itself in transport experiments through quantization of the Hall resistance to an exact rational fraction of h/e, and concomitantly vanishing longitudinal resistivity. Its relevant energy scale is only a few degrees kelvin. The quantization is a consequence of the spontaneous formation of an energy gap separating the condensed ground state from its rather elusive quasiparticle excitations. The theoretical understanding of the novel quantum liquids which underlie the FQHE has predominantly emerged from an ingenious many-particle wave function strongly supported by numerous few-particle simulations. Theory has now constructed a complex model for ideal two-dimensional electron systems in the presence of high magnetic fields and makes definitive, often fascinating predictions. Experiments have successively uncovered odd-denominator fractional states reaching presently to 7/13. The application of new experimental tools to the FQHE, such as optics, microwaves, and phonon techniques promises the direct observation of such parameters as the gap energy and possibly even some of the more elusive quantities in the future. While theory and experiment in the FQHE appear to be converging, there remains considerable room for challenging surprises. This paper provides a concise overview of the FQHE. It focuses on the experimental aspects and states, but does not expand on the theoretical advances. 70 refs., 11 figs

  2. 2014 CERN Accelerator Schools: Plasma Wake Acceleration

    CERN Multimedia

    2014-01-01

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

  3. Scanning Hall probe microscopy of a diluted magnetic semiconductor

    International Nuclear Information System (INIS)

    Kweon, Seongsoo; Samarth, Nitin; Lozanne, Alex de

    2009-01-01

    We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga 0.94 Mn 0.06 As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 μm wide and fairly stable with temperature. Magnetic clusters are observed above T C , which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

  4. Scanning Hall probe microscopy of a diluted magnetic semiconductor

    Science.gov (United States)

    Kweon, Seongsoo; Samarth, Nitin; de Lozanne, Alex

    2009-05-01

    We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga0.94Mn0.06As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 μm wide and fairly stable with temperature. Magnetic clusters are observed above TC, which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

  5. CERN Accelerator School & ELETTRA Synchrotron Light Laboratory announce a course on "Accelerator Physics" (Intermediate level), at the Abdus Salam International Center for Theoretical Physics, Adriatico Guesthouse, Trieste, Italy, 2 - 14 October 2005

    CERN Multimedia

    2005-01-01

    The Intermediate level course is clearly conceived as the logical continuation of the Introductory level course for those being active in the field of Accelerator Physics. However, it is also often considered as an excellent opportunity to either discover and receive a basic training in a new field, or for refreshing or keeping up-to-date people's expertise in the field.

  6. Acceleration of 14C beams in electrostatic accelerators

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  7. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1997-01-01

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

  8. The quantum Hall effects: Philosophical approach

    Science.gov (United States)

    Lederer, P.

    2015-05-01

    The Quantum Hall Effects offer a rich variety of theoretical and experimental advances. They provide interesting insights on such topics as gauge invariance, strong interactions in Condensed Matter physics, emergence of new paradigms. This paper focuses on some related philosophical questions. Various brands of positivism or agnosticism are confronted with the physics of the Quantum Hall Effects. Hacking's views on Scientific Realism, Chalmers' on Non-Figurative Realism are discussed. It is argued that the difficulties with those versions of realism may be resolved within a dialectical materialist approach. The latter is argued to provide a rational approach to the phenomena, theory and ontology of the Quantum Hall Effects.

  9. Quantized Hall conductance as a topological invariant

    International Nuclear Information System (INIS)

    Niu, Q.; Thouless, Ds.J.; Wu, Y.S.

    1984-10-01

    Whenever the Fermi level lies in a gap (or mobility gap) the bulk Hall conductance can be expressed in a topologically invariant form showing the quantization explicitly. The new formulation generalizes the earlier result by TKNN to the situation where many body interaction and substrate disorder are also present. When applying to the fractional quantized Hall effect we draw the conclusion that there must be a symmetry breaking in the many body ground state. The possibility of writing the fractionally quantized Hall conductance as a topological invariant is also carefully discussed. 19 references

  10. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  11. ACCELERATORS: Nonlinear dynamics in Sardinia

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    In the last few years, two schools devoted to accelerator physics have been set up, one on either side of the Atlantic. The US School on High Energy Particle Accelerators has organized Summer Schools on the physics of particle accelerators, hosted by the major American Laboratories, each year since 1981

  12. ACCELERATORS: Nonlinear dynamics in Sardinia

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1985-05-15

    In the last few years, two schools devoted to accelerator physics have been set up, one on either side of the Atlantic. The US School on High Energy Particle Accelerators has organized Summer Schools on the physics of particle accelerators, hosted by the major American Laboratories, each year since 1981.

  13. High Gradient Accelerator Research

    International Nuclear Information System (INIS)

    Temkin, Richard

    2016-01-01

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

  14. A Green Fabry-Perot Cavity for Jefferson Lab Hall A Compton Polarimetry

    International Nuclear Information System (INIS)

    Rakhman, Abdurahim; Souder, Paul; Nanda, Sirish

    2009-01-01

    A green laser (CW, 532 nm) based Fabry-Perot cavity for high precision Compton Polarimetry is under development in Hall A of the Jefferson Laboratory. In this paper, we present the principle and the preliminary studies for our test cavity.

  15. Contribution of the study of the Hall Effect. Hall Effect of powder products

    International Nuclear Information System (INIS)

    Cherville, Jean

    1961-01-01

    This research thesis reports the development of an apparatus aimed at measuring the Hall Effect and the magneto-resistance of powders at room temperature and at the liquid nitrogen temperature. The author also proposes a theoretical contribution to the Hall Effect and reports the calculation of conditions to be met to obtain a correct value for the Hall constant. Results are experimentally verified. The method is then applied to the study of a set of powdered pre-graphitic graphites. The author shows that their Hall coefficient confirms the model already proposed by Mrozowski. The study of the Hall Effect of any kind of powders can thus be performed, and the Hall Effect can therefore be a mean to study mineral and organic compounds, and notably powdered biological molecules [fr

  16. The infrared Hall effect in YBCO: Temperature and frequency dependence of Hall scattering

    International Nuclear Information System (INIS)

    Grayson, M.; Cerne, J.; Drew, H.D.; Schmadel, D.C.; Hughes, R.; Preston, J.S.; Kung, P.J.; Vale, L.

    1999-01-01

    The authors measure the Hall angle, θ H , in YBCO films in the far- and mid-infrared to determine the temperature and frequency dependence of the Hall scattering. Using novel modulation techniques they measure both the Faraday rotation and ellipticity induced by these films in high magnetic fields to deduce the complex conductivity tensor. They observe a strong temperature dependence of the mid-infrared Hall conductivity in sharp contrast to the weak dependence of the longitudinal conductivity. By fitting the frequency dependent normal state Hall angle to a Lorentzian θ H (ω) = ω H /(γ H minus iω) they find the Hall frequency, ω H , is nearly independent of temperature. The Hall scattering rate, γ H , is consistent with γ H ∼ T 2 up to 200 K and is remarkably independent of IR frequency suggesting non-Fermi liquid behavior

  17. Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2

    Science.gov (United States)

    Firoz Islam, SK; Benjamin, Colin

    2016-09-01

    The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms.

  18. 2014 Accelerators meeting, Grenoble

    International Nuclear Information System (INIS)

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

    2014-10-01

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

  19. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun; Grigoryan, Vahram L.; Maekawa, Sadamichi; Wang, Xuhui; Xiao, Jiang

    2015-01-01

    induced by surface roughness subscribes only to the side-jump contribution but not the skew scattering. The paradigm proposed in this paper provides the second, not if only, alternative to generate a sizable spin Hall effect.

  20. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    . When band mixing between multiple Landau levels is present, mesoscopic effects cause a crossover from a sequence of quantum Hall transitions for weak disorder to classical behavior for strong disorder. This behavior may be of relevance ...

  1. Plasmon Geometric Phase and Plasmon Hall Shift

    Science.gov (United States)

    Shi, Li-kun; Song, Justin C. W.

    2018-04-01

    The collective plasmonic modes of a metal comprise a simple pattern of oscillating charge density that yields enhanced light-matter interaction. Here we unveil that beneath this familiar facade plasmons possess a hidden internal structure that fundamentally alters its dynamics. In particular, we find that metals with nonzero Hall conductivity host plasmons with an intricate current density configuration that sharply departs from that of ordinary zero Hall conductivity metals. This nontrivial internal structure dramatically enriches the dynamics of plasmon propagation, enabling plasmon wave packets to acquire geometric phases as they scatter. At boundaries, these phases accumulate allowing plasmon waves that reflect off to experience a nonreciprocal parallel shift. This plasmon Hall shift, tunable by Hall conductivity as well as plasmon wavelength, displaces the incident and reflected plasmon trajectories and can be readily probed by near-field photonics techniques. Anomalous plasmon geometric phases dramatically enrich the nanophotonics toolbox, and yield radical new means for directing plasmonic beams.

  2. Novel optical probe for quantum Hall system

    Indian Academy of Sciences (India)

    to explore Landau levels of a two-dimensional electron gas (2DEG) in modulation doped ... Keywords. Surface photovoltage spectroscopy; quantum Hall effect; Landau levels; edge states. ... An optical fibre carries light from tunable diode laser.

  3. AA under construction in its hall

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The Antiproton Accumulator was installed in a specially built hall. Here we see it at an "early" stage of installation, just a few magnets on the floor, no vacuum chamber at all, but: 3 months later there was circulating beam !

  4. Elementary theory of quantum Hall effect

    Directory of Open Access Journals (Sweden)

    Keshav N. Shrivastava

    2008-04-01

    Full Text Available The Hall effect is the generation of a current perpendicular to both the direction of the applied electric as well as magnetic field in a metal or in a semiconductor. It is used to determine the concentration of electrons. The quantum Hall effect with integer quantization was discovered by von Klitzing and fractionally charged states were found by Tsui, Stormer and Gossard. Robert Laughlin explained the quantization of Hall current by using “flux quantization” and introduced incompressibility to obtain the fractional charge. We have developed the theory of the quantum Hall effect by using the theory of angular momentum. Our predicted fractions are in accord with those measured. We emphasize our explanation of the observed phenomena. We use spin to explain the fractional charge and hence we discover spin-charge locking.

  5. The fluctuation Hall conductivity and the Hall angle in type-II superconductor under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Tinh, Bui Duc, E-mail: tinhbd@hnue.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Hoc, Nguyen Quang; Thu, Le Minh [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)

    2016-02-15

    Highlights: • The time-dependent Ginzburg–Landau was used to calculate fluctuation Hall conductivity and Hall angle in type-II superconductor in 2D and 3D. • We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. • The results were compared to the experimental data on YBCO. - Abstract: The fluctuation Hall conductivity and the Hall angle, describing the Hall effect, are calculated for arbitrary value of the imaginary part of the relaxation time in the frame of the time-dependent Ginzburg–Landau theory in type II-superconductor with thermal noise describing strong thermal fluctuations. The self-consistent Gaussian approximation is used to treat the nonlinear interaction term in dynamics. We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. The results are compared with experimental data on high-T{sub c} superconductor.

  6. NAS Decadal Review Town Hall

    Science.gov (United States)

    The National Academies of Sciences, Engineering and Medicine is seeking community input for a study on the future of materials research (MR). Frontiers of Materials Research: A Decadal Survey will look at defining the frontiers of materials research ranging from traditional materials science and engineering to condensed matter physics. Please join members of the study committee for a town hall to discuss future directions for materials research in the United States in the context of worldwide efforts. In particular, input on the following topics will be of great value: progress, achievements, and principal changes in the R&D landscape over the past decade; identification of key MR areas that have major scientific gaps or offer promising investment opportunities from 2020-2030; and the challenges that MR may face over the next decade and how those challenges might be addressed. This study was requested by the Department of Energy and the National Science Foundation. The National Academies will issue a report in 2018 that will offer guidance to federal agencies that support materials research, science policymakers, and researchers in materials research and other adjoining fields. Learn more about the study at http://nas.edu/materials.

  7. Are tent halls subject to property tax?

    Directory of Open Access Journals (Sweden)

    Mariusz Macudziński

    2016-12-01

    Full Text Available The presented publication is a response to currently asked questions and interpretative doubts of taxpayers and tax authorities, namely whether tent halls are subject to property tax. General issues connected with an entity and a subject of taxation of this tax are presented herein. The answer to the question asked is then provided through the qualification of constructions works and the allocation of tent halls in the proper category of the works, with the use of the current law.

  8. Fractional statistics and fractional quantized Hall effect

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.

    1985-01-01

    The authors suggest that the origin of the odd-denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which govern quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics do not allow coexistence of a large number of quasiparticles at fillings with an even denominator. Thus, no Hall plateau can be formed at these fillings, regardless of the presence of an energy gap. 15 references

  9. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)

    R.A.Hasan

    2006-01-01

    Full Text Available The Hall effect in organic layered conductors with a multisheeted Fermi surfaces was considered. It is shown that the experimental study of Hall effect and magnetoresistance anisotropy at different orientations of current and a quantizing magnetic field relative to the layers makes it possible to determine the contribution of various charge carriers groups to the conductivity, and to find out the character of Fermi surface anisotropy in the plane of layers.

  10. Plasma accelerators

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  11. Integrated Stirling Convertor and Hall Thruster Test Conducted

    Science.gov (United States)

    Mason, Lee S.

    2002-01-01

    An important aspect of implementing Stirling Radioisotope Generators on future NASA missions is the integration of the generator and controller with potential spacecraft loads. Some recent studies have indicated that the combination of Stirling Radioisotope Generators and electric propulsion devices offer significant trip time and payload fraction benefits for deep space missions. A test was devised to begin to understand the interactions between Stirling generators and electric thrusters. An electrically heated RG- 350 (350-W output) Stirling convertor, designed and built by Stirling Technology Company of Kennewick, Washington, under a NASA Small Business Innovation Research agreement, was coupled to a 300-W SPT-50 Hall-effect thruster built for NASA by the Moscow Aviation Institute (RIAME). The RG-350 and the SPT-50 shown, were installed in adjacent vacuum chamber ports at NASA Glenn Research Center's Electric Propulsion Laboratory, Vacuum Facility 8. The Stirling electrical controller interfaced directly with the Hall thruster power-processing unit, both of which were located outside of the vacuum chamber. The power-processing unit accepted the 48 Vdc output from the Stirling controller and distributed the power to all the loads of the SPT-50, including the magnets, keeper, heater, and discharge. On February 28, 2001, the Glenn test team successfully operated the Hall-effect thruster with the Stirling convertor. This is the world's first known test of a dynamic power source with electric propulsion. The RG-350 successfully managed the transition from the purely resistive load bank within the Stirling controller to the highly capacitive power-processing unit load. At the time of the demonstration, the Stirling convertor was operating at a hot temperature of 530 C and a cold temperature of -6 C. The linear alternator was producing approximately 250 W at 109 Vac, while the power-processing unit was drawing 175 W at 48 Vdc. The majority of power was delivered to the

  12. Overview of accelerators in medicine

    International Nuclear Information System (INIS)

    Lennox, A.J.

    1993-06-01

    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

  13. Linear Accelerators

    International Nuclear Information System (INIS)

    Vretenar, M

    2014-01-01

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

  14. Hall effect measurements on proton-irradiated ROSE samples

    International Nuclear Information System (INIS)

    Biggeri, U.; Bruzzi, M.; Borchi, E.

    1997-01-01

    Bulk samples obtained from two wafers of a silicon monocrystal material produced by Float-Zone refinement have been analyzed using the four-point probe method. One of the wafers comes from an oxygenated ingot; two sets of pure and oxygenated samples have been irradiated with 24 GeV/c protons in the fluence range from 10 13 p/cm 2 to 2x10 14 p/cm 2 . Van der Pauw resistivity and Hall coefficient have been measured before and after irradiation as a function of the temperature. A thermal treatment (30 minutes at 100C) has been performed to accelerate the reverse annealing effect in the irradiated silicon. The irradiated samples show the same exponential dependence of the resistivity and of the Hall coefficient on the temperature from 370K to 100K, corresponding to the presence of radiation-induced deep energy levels around 0.6-0.7eV in the silicon gap. The free carrier concentrations (n, p) have been evaluated in the investigated fluence range. The inversion of the conductivity type from n to p occurred respectively at 7x10 13 p/cm 2 and at 4x10 13 p/cm 2 before and after the annealing treatment, for both the two sets. Only slight differences have been detected between the pure and oxygenated samples

  15. Underground laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, A., E-mail: Bettini@pd.infn.i [Padua University and INFN Section, Dipartimento di Fisca G. Galilei, Via Marzolo 8, 35131 Padova (Italy); Laboratorio Subterraneo de Canfranc, Plaza Ayuntamiento n1 2piso, Canfranc (Huesca) (Spain)

    2011-01-21

    Underground laboratories provide the low radioactive background environment necessary to frontier experiments in particle and nuclear astrophysics and other disciplines, geology and biology, that can profit of their unique characteristics. The cosmic silence allows to explore the highest energy scales that cannot be reached with accelerators by searching for extremely rare phenomena. I will briefly review the facilities that are operational or in an advanced status of approval around the world.

  16. 75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment

    Science.gov (United States)

    2010-04-30

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13652-000-Montana] Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment April 22, 2010. In accordance with the National Environmental Policy Act of 1969, as amended, and the Federal Energy Regulatory...

  17. Accelerator Service

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  18. The bremsstrahlung tagged photon beam in Hall B at JLab

    CERN Document Server

    Sober, D I; Longhi, A; Matthews, S K; O'Brien, J T; Berman, B L; Briscoe, W J; Cole, P L; Connelly, J P; Dodge, W R; Murphy, L Y; Philips, S A; Dugger, M K; Lawrence, D; Ritchie, B G; Smith, E S; Lambert, J M; Anciant, E; Audit, G; Auger, T; Marchand, C; Klusman, M; Napolitano, J; Khandaker, M A; Salgado, C W; Sarty, A J

    2000-01-01

    We describe the design and commissioning of the photon tagging beamline installed in experimental Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This system can tag photon energies over a range from 20% to 95% of the incident electron energy, and is capable of operation with beam energies up to 6.1 GeV. A single dipole magnet is combined with a hodoscope containing two planar arrays of plastic scintillators to detect energy-degraded electrons from a thin bremsstrahlung radiator. The first layer of 384 partially overlapping small scintillators provides photon energy resolution, while the second layer of 61 larger scintillators provides the timing resolution necessary to form a coincidence with the corresponding nuclear interaction triggered by the tagged photon. The definitions of overlap channels in the first counter plane and of geometric correlation between the two planes are determined using digitized time information from the individual counters. Auxiliary beamline devices are briefl...

  19. Overview of the J-PARC (Japan Proton Accelerator Research Complex) Project

    International Nuclear Information System (INIS)

    Nagamiya, Shoji

    2010-01-01

    The construction of the J-PARC Project started in April of 2001. After 8 years of construction period, the project was completed in the spring of 2009. Three accelerator elements (Linac, 3 GeV proton synchrotron and 50 GeV proton synchrotron) are now working. Also, three experimental halls (materials and life experimental hall, hadron experimental hall, and neutrino experimental hall) are in operation. In this article I review all these facilities and their scientific goals. In addition, I would like to overview the current and future scope of this J-PARC facility. (author)

  20. New life for CERN's first accelerator

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    Building 300 right in the middle of the CERN site houses a special "antique": the Laboratory's very first accelerator. After several years in the wilderness following its decommissioning in 1990, the Synchrocyclotron is set to take on a new lease of life in the near future, this time as a visitor attraction.   The Synchrocyclotron as it was in 1975; it will be restored to this configuration for public viewing. The Synchrocyclotron (SC) began operation in 1957, two years before the PS was commissioned. Running at an energy of 600 MeV and producing beams of protons, neutrons, muons and pions, it helped to further research in the nuclear physics field for no fewer than 33 years, providing beams for various decay experiments as well as the muon capture experiment (*). Since the SC was decommissioned in 1990, three of its four buildings (160, 161 and 301) have been converted into offices for members of the ALICE collaboration, but the shielded hall housing the machine it...

  1. Status Report on the accelerators operation

    International Nuclear Information System (INIS)

    Biri, S.; Kormany, Z.; Berzi, I.; Racz, R.; Perduk, Z.; Vajda, I.

    2012-01-01

    In 2012 our particle accelerators operated as scheduled, safely and without major or long breakdowns. The utilization rates of the accelerators slightly increased in comparing to the preceding year (see Fig. 1). The cyclotron delivered 1900 hours and the 40-years old 5 MeV Van de Graaff generator supplied more than 2400 hours. The 1 MeV Van de Graaff accelerator was also operated for short basic physics experiments (160 hours). The plasma and beam on-target time at the ECR ion source was similar to the preceding years (410 hours). The isotope separator, as ion beam accelerator was utilized only for a few hours in 2012, since the research and development in this lab focused on other fields. Nevertheless it is continuously available for research requiring special deposition techniques and for isotope tracing studies. We developed the first version of an on-line accelerator status display software. Through our homepage anybody from anywhere can now check the current state of the cyclotron, VdG-5 and ECRIS accelerators. While in 2010 the cyclotron celebrated the 25 th anniversary of its regular starting-up, in 2012 two of our other accelerators had also anniversary. The ECR Ion Source project started 20 years ago, in 1992. To celebrate it, a scientific symposium was hold in September. In the symposium - beyond the high number of audience - the leaders of the Hungarian Academy of Sciences, the University of Debrecen and the City of Debrecen attended, as well. The local and national press reported about the event in many form. A short summary of the symposium is in our homepage (in Hungarian). We had the 40 th anniversary of the regular use of the 5 MeV Van de Graaff accelerator. Having obtained the final approval of the project the 'Electrostatic Accelerator Department' was organized in the Institute in July 1967 with the tasks to perform the planning and construction of the laboratory, to make all the preparations necessary for the intensive scientific use of the

  2. Charge carrier coherence and Hall effect in organic semiconductors

    Science.gov (United States)

    Yi, H. T.; Gartstein, Y. N.; Podzorov, V.

    2016-01-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor. PMID:27025354

  3. Charge carrier coherence and Hall effect in organic semiconductors.

    Science.gov (United States)

    Yi, H T; Gartstein, Y N; Podzorov, V

    2016-03-30

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.

  4. Illinois Accelerator Research Center

    Science.gov (United States)

    Kroc, Thomas K.; Cooper, Charlie A.

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

  5. Dr. Hall and the work cure.

    Science.gov (United States)

    Reed, Kathlyn L

    2005-01-01

    Herbert James Hall, MD (1870-1923), was a pioneer in the systematic and organized study of occupation as therapy for persons with nervous and mental disorders that he called the "work cure." He began his work in 1904 during the early years of the Arts and Crafts Movement in the United States. His primary interest was the disorder neurasthenia, a condition with many symptoms including chronic fatigue, stress, and inability to work or perform everyday tasks. The prevailing treatment of the day was absolute bed rest known as the "rest cure." Hall believed that neurasthenia was not caused by overwork but by faulty living habits that could be corrected through an ordered life schedule and selected occupations. He identified several principles of therapy that are still used today including graded activity and energy conservation. Dr. Adolph Meyer credits Hall for organizing the ideas on the therapeutic use of occupation (Meyer, 1922). Hall also provided the name American Occupational Therapy Association for the professional organization and served as the fourth president. For his many contributions to the profession Hall deserves to be recognized as a major contributor to the development and organization of occupational therapy.

  6. A new CMOS Hall angular position sensor

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, R.S.; Drljaca, P. [Swiss Federal Inst. of Tech., Lausanne (Switzerland); Schott, C.; Racz, R. [SENTRON AG, Zug (Switzerland)

    2001-06-01

    The new angular position sensor consists of a combination of a permanent magnet attached to a shaft and of a two-axis magnetic sensor. The permanent magnet produces a magnetic field parallel with the magnetic sensor plane. As the shaft rotates, the magnetic field also rotates. The magnetic sensor is an integrated combination of a CMOS Hall integrated circuit and a thin ferromagnetic disk. The CMOS part of the system contains two or more conventional Hall devices positioned under the periphery of the disk. The ferromagnetic disk converts locally a magnetic field parallel with the chip surface into a field perpendicular to the chip surface. Therefore, a conventional Hall element can detect an external magnetic field parallel with the chip surface. As the direction of the external magnetic field rotates in the chip plane, the output voltage of the Hall element varies as the cosine of the rotation angle. By placing the Hall elements at the appropriate places under the disk periphery, we may obtain the cosine signals shifted by 90 , 120 , or by any other angle. (orig.)

  7. Composite fermions in the quantum Hall effect

    International Nuclear Information System (INIS)

    Johnson, B.L.; Kirczenow, G.

    1997-01-01

    The quantum Hall effect and associated quantum transport phenomena in low-dimensional systems have been the focus of much attention for more than a decade. Recent theoretical development of interesting quasiparticles - 'composite fermions' - has led to significant advances in understanding and predicting the behaviour of two-dimensional electron systems under high transverse magnetic fields. Composite fermions may be viewed as fermions carrying attached (fictitious) magnetic flux. Here we review models of the integer and fractional quantum Hall effects, including the development of a unified picture of the integer and fractional effects based upon composite fermions. The composite fermion picture predicts remarkable new physics: the formation of a Fermi surface at high magnetic fields, and anomalous ballistic transport, thermopower, and surface acoustic wave behaviour. The specific theoretical predictions of the model, as well as the body of experimental evidence for these phenomena are reviewed. We also review recent edge-state models for magnetotransport in low-dimensional devices based on the composite fermion picture. These models explain the fractional quantum Hall effect and transport phenomena in nanoscale devices in a unified framework that also includes edge state models of the integer quantum Hall effect. The features of the composite fermion edge-state model are compared and contrasted with those of other recent edge-state models of the fractional quantum Hall effect. (author)

  8. Air temperature gradient in large industrial hall

    Science.gov (United States)

    Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia

    2017-11-01

    In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.

  9. Field theory approach to quantum hall effect

    International Nuclear Information System (INIS)

    Cabo, A.; Chaichian, M.

    1990-07-01

    The Fradkin's formulation of statistical field theory is applied to the Coulomb interacting electron gas in a magnetic field. The electrons are confined to a plane in normal 3D-space and also interact with the physical 3D-electromagnetic field. The magnetic translation group (MTG) Ward identities are derived. Using them it is shown that the exact electron propagator is diagonalized in the basis of the wave functions of the free electron in a magnetic field whenever the MTG is unbroken. The general tensor structure of the polarization operator is obtained and used to show that the Chern-Simons action always describes the Hall effect properties of the system. A general proof of the Streda formula for the Hall conductivity is presented. It follows that the coefficient of the Chern-Simons terms in the long-wavelength approximation is exactly given by this relation. Such a formula, expressing the Hall conductivity as a simple derivative, in combination with diagonal form of the full propagator allows to obtain a simple expressions for the filling factor and the Hall conductivity. Indeed, these results, after assuming that the chemical potential lies in a gap of the density of states, lead to the conclusion that the Hall conductivity is given without corrections by σ xy = νe 2 /h where ν is the filling factor. In addition it follows that the filling factor is independent of the magnetic field if the chemical potential remains in the gap. (author). 21 ref, 1 fig

  10. Extrinsic spin Hall effect in graphene

    Science.gov (United States)

    Rappoport, Tatiana

    The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. In addition, many applications also require the generation of spin currents in graphene. Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent skew scattering of electrons by impurities in the presence of spin-orbit interaction. This effect can be used to efficiently convert charge currents into spin-polarized currents. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic cluster and show that a large spin Hall effect can appear due to skew scattering. While this spin-orbit coupling is small if compared with what it is found in metals, the effect is strongly enhanced in the presence of resonant scattering, giving rise to robust spin Hall angles. I will present our single impurity scattering calculations done with exact partial-wave expansions and complement the analysis with numerical results from a novel real-space implementation of the Kubo formalism for tight-binding Hamiltonians. The author acknowledges the Brazilian agencies CNPq, CAPES, FAPERJ and INCT de Nanoestruturas de Carbono for financial support.

  11. The auroral electron accelerator

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  12. Accelerator programme at CAT

    International Nuclear Information System (INIS)

    Ramamurthi, S.S.

    1991-01-01

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

  13. Anomalous Hall effect in semiconductor quantum wells in proximity to chiral p -wave superconductors

    Science.gov (United States)

    Yang, F.; Yu, T.; Wu, M. W.

    2018-05-01

    By using the gauge-invariant optical Bloch equation, we perform a microscopic kinetic investigation on the anomalous Hall effect in chiral p -wave superconducting states. Specifically, the intrinsic anomalous Hall conductivity in the absence of the magnetic field is zero as a consequence of Galilean invariance in our description. As for the extrinsic channel, a finite anomalous Hall current is obtained from the impurity scattering with the optically excited normal quasiparticle current even at zero temperature. From our kinetic description, it can be clearly seen that the excited normal quasiparticle current is due to an induced center-of-mass momentum of Cooper pairs through the acceleration driven by ac electric field. For the induced anomalous Hall current, we show that the conventional skew-scattering channel in the linear response makes the dominant contribution in the strong impurity interaction. In this case, our kinetic description as a supplementary viewpoint mostly confirms the results of Kubo formalism in the literature. Nevertheless, in the weak impurity interaction, this skew-scattering channel becomes marginal and we reveal that an induction channel from the Born contribution dominates the anomalous Hall current. This channel, which has long been overlooked in the literature, is due to the particle-hole asymmetry by nonlinear optical excitation. Finally, we study the case in the chiral p -wave superconducting state with a transverse conical magnetization, which breaks the Galilean invariance. In this situation, the intrinsic anomalous Hall conductivity is no longer zero. Comparison of this intrinsic channel with the extrinsic one from impurity scattering is addressed.

  14. Localization in a quantum spin Hall system.

    Science.gov (United States)

    Onoda, Masaru; Avishai, Yshai; Nagaosa, Naoto

    2007-02-16

    The localization problem of electronic states in a two-dimensional quantum spin Hall system (that is, a symplectic ensemble with topological term) is studied by the transfer matrix method. The phase diagram in the plane of energy and disorder strength is exposed, and demonstrates "levitation" and "pair annihilation" of the domains of extended states analogous to that of the integer quantum Hall system. The critical exponent nu for the divergence of the localization length is estimated as nu congruent with 1.6, which is distinct from both exponents pertaining to the conventional symplectic and the unitary quantum Hall systems. Our analysis strongly suggests a different universality class related to the topology of the pertinent system.

  15. Hall probe magnetometer for SSC magnet cables

    International Nuclear Information System (INIS)

    Cross, R.W.; Goldfarb, R.B.

    1991-01-01

    The authors of this paper constructed a Hall probe magnetometer to measure the magnetization hysteresis loops of Superconducting Super Collider magnet cables. The instrument uses two Hall-effect field sensors to measure the applied field H and the magnetic induction B. Magnetization M is calculated from the difference of the two quantities. The Hall probes are centered coaxially in the bore of a superconducting solenoid with the B probe against the sample's broad surface. An alternative probe arrangement, in which M is measured directly, aligns the sample probe parallel to the field. The authors measured M as a function of H and field cycle rate both with and without a dc transport current. Flux creep as a function of current was measured from the dependence of ac loss on the cycling rate and from the decay of magnetization with time. Transport currents up to 20% of the critical current have minimal effect on magnetization and flux creep

  16. Spin Hall Effect in Doped Semiconductor Structures

    Science.gov (United States)

    Tse, Wang-Kong; Das Sarma, Sankar

    2006-03-01

    We present a microscopic theory of the extrinsic spin Hall effect based on the diagrammatic perturbation theory. Side-jump (SJ) and skew-scattering (SS) contributions are explicitly taken into account to calculate the spin Hall conductivity, and we show their effects scale as σxy^SJ/σxy^SS ˜(/τ)/ɛF, where τ being the transport relaxation time. Motivated by recent experimental work we apply our theory to n-doped and p-doped 3D and 2D GaAs structures, obtaining analytical formulas for the SJ and SS contributions. Moreover, the ratio of the spin Hall conductivity to longitudinal conductivity is found as σs/σc˜10-3-10-4, in reasonable agreement with the recent experimental results of Kato et al. [Science 306, 1910 (2004)] in n-doped 3D GaAs system.

  17. Berkeley Lab Laser Accelerator (BELLA) facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Berkeley Lab Laser Accelerator (BELLA) facility (formerly LOASIS) develops advanced accelerators and radiation sources. High gradient (1-100 GV/m) laser-plasma...

  18. Developments in Scanning Hall Probe Microscopy

    Science.gov (United States)

    Chouinard, Taras; Chu, Ricky; David, Nigel; Broun, David

    2009-05-01

    Low temperature scanning Hall probe microscopy is a sensitive means of imaging magnetic structures with high spatial resolution and magnetic flux sensitivity approaching that of a Superconducting Quantum Interference Device. We have developed a scanning Hall probe microscope with novel features, including highly reliable coarse positioning, in situ optimization of sensor-sample alignment and capacitive transducers for linear, long range positioning measurement. This has been motivated by the need to reposition accurately above fabricated nanostructures such as small superconducting rings. Details of the design and performance will be presented as well as recent progress towards time-resolved measurements with sub nanosecond resolution.

  19. Inverse spin Hall effect by spin injection

    Science.gov (United States)

    Liu, S. Y.; Horing, Norman J. M.; Lei, X. L.

    2007-09-01

    Motivated by a recent experiment [S. O. Valenzuela and M. Tinkham, Nature (London) 442, 176 (2006)], the authors present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Their theoretical results are in good agreement with the experimental data. It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering.

  20. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues...... in Denmark and a questionnaire was used in a subjective assessment of those venues with professional rock musicians and sound engineers. Correlations between the objective and subjective results lead, among others, to a recommendation for reverberation time as a function of hall volume. Since the bass...

  1. Proton knock-out in Hall A

    International Nuclear Information System (INIS)

    Jager, K. de

    2003-01-01

    Proton knock-out is studied in a broad program in Hall A at Jefferson Lab. The first experiment performed in Hall A studied the 16 O(e,e'p) reaction. Since then proton knock-out experiments have studied a variety of aspects of that reaction, from single-nucleon properties to its mechanism, such as final-state interactions and two-body currents, in nuclei from 2 H to 16 O. In this review the accomplishments of this program will be summarized and an outlook given of expected future results. (orig.)

  2. Theory of fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1984-09-01

    A theory of the fractional quantum Hall effect is constructed by introducing 3-particle interactions breaking the symmetry for ν=1/3 according to a degeneracy theorem proved here. An order parameter is introduced and a gap in the single particle spectrum is found. The critical temperature, critical filling number and critical behaviour are determined as well as the Ginzburg-Landau equation coefficients. A first principle calculation of the Hall current is given. 3, 5, 7 electron tunneling and Josephson interference effects are predicted. (author)

  3. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1996-04-01

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

  4. Neutrons from rock radioactivity in the new Canfranc underground laboratory

    International Nuclear Information System (INIS)

    Amare, J; Bauluz, B; Beltran, B; Carmona, J M; Cebrian, S; GarcIa, E; Gomez, H; Irastorza, I G; Luzon, G; MartInez, M; Morales, J; Solorzano, A Ortiz de; Pobes, C; Jpuimedon; RodrIguez, A; Ruz, J; Sarsa, M L; Torres, L; Villar, J A

    2006-01-01

    Measurements of radioactivity and composition of rock from the main hall of the new Canfranc underground laboratory are reported. Estimates of neutron production by spontaneous fission and (α, n) reactions are given

  5. Future accelerators (?)

    Energy Technology Data Exchange (ETDEWEB)

    John Womersley

    2003-08-21

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

  6. Welcome to USA 15, the first large underground hall for the LHC

    CERN Multimedia

    2001-01-01

    The first of the four huge underground halls for LHC is ready. USA 15 will be the service hall for ATLAS. It has taken three years to finish the first underground hall for LHC. It is 62 metres long and 20 metres diameter. USA 15 could be called the 'new world' for LHC construction. Although the acronym has nothing to do with the United States. In the terminology of the underground construction for the future accelerator, USA stands for Underground Service ATLAS. This is the first of the four big underground halls for LHC to be finished. Wednesday 8 August, it was officially handed over to the ST division by the collaboration of contractors and consultants who carried out the work. These are CCC (CERN civil contractors) composed of the companies Porr-Asdag (Austria), Baresel (Germany) and Zschokke-Locher (Switzerland) and the consultant EDF-KP composed of EDF (France) and Knight and Piésold (United Kingdom). For three years these firms excavated and concreted the undergro...

  7. Bound values for Hall conductivity of heterogeneous medium under ...

    Indian Academy of Sciences (India)

    - ditions in inhomogeneous medium has been studied. It is shown that bound values for. Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect ...

  8. Accelerating with industry

    International Nuclear Information System (INIS)

    Southworth, Brian

    1992-01-01

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

  9. Hamburg Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-10-15

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

  10. BNL accelerator plans

    International Nuclear Information System (INIS)

    Lowenstein, D.I.

    1986-01-01

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

  11. Accelerating with industry

    Energy Technology Data Exchange (ETDEWEB)

    Southworth, Brian

    1992-06-15

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

  12. Hamburg Accelerator Conference

    International Nuclear Information System (INIS)

    Wilson, Edmund J.N.

    1992-01-01

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

  13. June 1992 Hall B collaboation meeting

    International Nuclear Information System (INIS)

    Dennis, L.

    1992-01-01

    The Hall B collaboration meeting at the CEBAF 1992 Summer Workshop consisted of technical and physics working group meetings, a special beam line devices working group meeting the first meeting of the membership committee, a technical representatives meeting and a full collaboration meeting. Highlights of these meetings are presented in this report

  14. Chapin Hall Projects and Publications. Autumn 1999.

    Science.gov (United States)

    Chicago Univ., IL. Chapin Hall Center for Children.

    This guide chronicles the ongoing work and writings of the Chapin Hall Center for Children at the University of Chicago, a policy research center dedicated to bringing sound information, rigorous analyses, innovative ideas, and an independent, multidisciplinary perspective to bear on policies and programs affecting children. This guide, organized…

  15. Quantum Hall Conductivity and Topological Invariants

    Science.gov (United States)

    Reyes, Andres

    2001-04-01

    A short survey of the theory of the Quantum Hall effect is given emphasizing topological aspects of the quantization of the conductivity and showing how topological invariants can be derived from the hamiltonian. We express these invariants in terms of Chern numbers and show in precise mathematical terms how this relates to the Kubo formula.

  16. Room acoustic properties of concert halls

    DEFF Research Database (Denmark)

    Gade, Anders Christian

    1996-01-01

    A large database of values of various room acoustic parameters has provided the basis for statistical analyses of how and how much the acoustic properties of concert halls are influenced by their size, shape, and absorption area (as deduced from measured reverberation time). The data have been...

  17. Pseudospin anisotropy classification of quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.

    2000-01-01

    Roč. 63, č. 3 (2000), s. 035305-1 - 035305-9 ISSN 0163-1829 R&D Projects: GA ČR GA202/98/0085 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.065, year: 2000

  18. Anomalous Hall effect in disordered multiband metals

    Czech Academy of Sciences Publication Activity Database

    Kovalev, A.A.; Sinova, Jairo; Tserkovnyak, Y.

    2010-01-01

    Roč. 105, č. 3 (2010), 036601/1-036601/4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.621, year: 2010

  19. Anomalous Hall conductivity: Local orbitals approach

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel

    2010-01-01

    Roč. 82, č. 4 (2010), 045115/1-045115/9 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * Berry phase correction * orbital polarization momentum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  20. Quantization and hall effect: necessities and difficulties

    International Nuclear Information System (INIS)

    Ahmed Bouketir; Hishamuddin Zainuddin

    1999-01-01

    The quantization procedure is a necessary tool for a proper understanding of many interesting quantum phenomena in modern physics. In this note, we focus on geometrical framework for such procedures, particularly the group-theoretic approach and their difficulties. Finally we look through the example of Hall effect as a quantized macroscopic phenomenon with group-theoretic quantization approach. (author)

  1. Spin Hall effect on a noncommutative space

    International Nuclear Information System (INIS)

    Ma Kai; Dulat, Sayipjamal

    2011-01-01

    We study the spin-orbital interaction and the spin Hall effect of an electron moving on a noncommutative space under the influence of a vector potential A(vector sign). On a noncommutative space, we find that the commutator between the vector potential A(vector sign) and the electric potential V 1 (r(vector sign)) of the lattice induces a new term, which can be treated as an effective electric field, and the spin Hall conductivity obtains some correction. On a noncommutative space, the spin current and spin Hall conductivity have distinct values in different directions, and depend explicitly on the noncommutative parameter. Once this spin Hall conductivity in different directions can be measured experimentally with a high level of accuracy, the data can then be used to impose bounds on the value of the space noncommutativity parameter. We have also defined a new parameter, σ=ρθ (ρ is the electron concentration, θ is the noncommutativity parameter), which can be measured experimentally. Our approach is based on the Foldy-Wouthuysen transformation, which gives a general Hamiltonian of a nonrelativistic electron moving on a noncommutative space.

  2. Future accelerators in Japan

    International Nuclear Information System (INIS)

    Toge, Nobu

    1993-01-01

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

  3. Prospect of quantum anomalous Hall and quantum spin Hall effect in doped kagome lattice Mott insulators.

    Science.gov (United States)

    Guterding, Daniel; Jeschke, Harald O; Valentí, Roser

    2016-05-17

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions.

  4. Advanced Superconducting Test Accelerator (ASTA)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Superconducting Test Accelerator (ASTA) facility will be based on upgrades to the existing NML pulsed SRF facility. ASTA is envisioned to contain 3 to 6...

  5. Digital technology impacts on the Arnhem transfer hall structural design

    NARCIS (Netherlands)

    Van de Straat, R.; Hofman, S.; Coenders, J.L.; Paul, J.C.

    2015-01-01

    The new Transfer Hall in Arnhem is one of the key projects to prepare the Dutch railways for the increased future demands for capacity. UNStudio developed a master plan in 1996 for the station area of which the completion of the Transfer Hall in 2015 will be a final milestone. The Transfer Hall is a

  6. Magnetoresistance in quantum Hall metals due to Pancharatnam ...

    Indian Academy of Sciences (India)

    Abstract. We derive the trial Hall resistance formula for the quantum Hall metals to address both the integer and fractional quantum Hall effects. Within the degenerate (and crossed) Landau levels, and in the presence of changing magnetic field strength, one can invoke two physical processes responsible for the electron ...

  7. Destruction of the fractional quantum Hall effect by disorder

    International Nuclear Information System (INIS)

    Laughlin, R.B.

    1985-07-01

    It is suggested that Hall steps in the fractional quantum Hall effect are physically similar to those in the ordinary quantum Hall effect. This proposition leads to a simple scaling diagram containing a new type of fixed point, which is identified with the destruction of the fractional states by disorder. 15 refs., 3 figs

  8. A Hall probe technique for characterizing high-temperature superconductors

    International Nuclear Information System (INIS)

    Zhang, J.; Sheldon, P.; Ahrenkiel, R.K.

    1992-01-01

    Thin-film GaAs Hall probes were fabricated by molecular beam epitaxy technology. A contactless technique was developed to characterize thin-film, high-temperature superconducting (HTSC) materials. The Hall probes detected the ac magnetic flux penetration through the high-temperature superconducting materials. The Hall detector has advantages over the mutual inductance magnetic flux detector

  9. Spin-singlet hierarchy in the fractional quantum Hall effect

    OpenAIRE

    Ino, Kazusumi

    1999-01-01

    We show that the so-called permanent quantum Hall states are formed by the integer quantum Hall effects on the Haldane-Rezayi quantum Hall state. Novel conformal field theory description along with this picture is deduced. The odd denominator plateaux observed around $\

  10. KEK (National Laboratory for High Energy Physics) annual report, 1985

    International Nuclear Information System (INIS)

    Arai, Masatoshi; Kaneko, Toshiaki; Mori, Yoshiharu; Nakai, Kozi; Nakamura, Kenzo; Oide, Katsuya; Sato, Shigeru

    1986-01-01

    Aiming at the completion of TRISTAN colliding beam complex, the laboratory engaged in the construction works throughout this year. Following the commissioning of a high current 200 MeV electron linac for positron production and of a 250 MeV positron linac in April, positrons were successfully accelerated through the existing electron linac and the accumulation ring in October. On March 21, 1986, the electron-position collision in the accumulation ring was observed in its first trial at 5 GeV with a luminosity of about 10 28 /cm 2 s. The main ring accelerator tunnel, four experimental halls and other associated buildings were completed in this fiscal year. Each of the TRISTAN experimental groups has engaged in the construction of its own detector complex, aiming at the completion of the system by the spring of 1987. In particular, large superconducting solenoid magnets were successfully operated in the test. A large computer system with FACOM M382s for TRISTAN data analysis was commissioned in October. It is the serious concern to establish safety measures for the whole TRISTAN project. The positron beam accelerated by the existing 2.5 GeV electron linac was also fed to the Photon Factory storage ring. The 12 GeV proton synchrotron started the experiment on hadron science from the beginning of this fiscal year after one year shutdown. (Kako, I.)

  11. Accelerator Center for Energy Research (ACER)

    Data.gov (United States)

    Federal Laboratory Consortium — The Accelerator Center for Energy Research (ACER) exploits radiation chemistry techniques to study chemical reactions (and other phenomena) by subjecting samples to...

  12. SSC accelerator availability allocation

    International Nuclear Information System (INIS)

    Dixon, K.T.; Franciscovich, J.

    1991-03-01

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

  13. Topological honeycomb magnon Hall effect: A calculation of thermal Hall conductivity of magnetic spin excitations

    Energy Technology Data Exchange (ETDEWEB)

    Owerre, S. A., E-mail: solomon@aims.ac.za [African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, Cape Town 7945, South Africa and Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, Ontario N2L 2Y5 (Canada)

    2016-07-28

    Quite recently, the magnon Hall effect of spin excitations has been observed experimentally on the kagome and pyrochlore lattices. The thermal Hall conductivity κ{sup xy} changes sign as a function of magnetic field or temperature on the kagome lattice, and κ{sup xy} changes sign upon reversing the sign of the magnetic field on the pyrochlore lattice. Motivated by these recent exciting experimental observations, we theoretically propose a simple realization of the magnon Hall effect in a two-band model on the honeycomb lattice. The magnon Hall effect of spin excitations arises in the usual way via the breaking of inversion symmetry of the lattice, however, by a next-nearest-neighbour Dzyaloshinsky-Moriya interaction. We find that κ{sup xy} has a fixed sign for all parameter regimes considered. These results are in contrast to the Lieb, kagome, and pyrochlore lattices. We further show that the low-temperature dependence on the magnon Hall conductivity follows a T{sup 2} law, as opposed to the kagome and pyrochlore lattices. These results suggest an experimental procedure to measure thermal Hall conductivity within a class of 2D honeycomb quantum magnets and ultracold atoms trapped in a honeycomb optical lattice.

  14. The Brookhaven Accelerator Test Facility

    International Nuclear Information System (INIS)

    Batchelor, K.; Ben-Zvi, I.; Fernow, R.C.; Fischer, J.; Fisher, A.S.; Gallardo, J.; Jialin, Xie; Kirk, H.G.; Parsa, Z.; Palmer, R.B.; Rao, T.; Rogers, J.; Sheehan, J.; Tsang, T.Y.F.; Ulc, S.; Van Steenbergen, A.; Woodle, M.; Zhang, R.S.; McDonald, K.T.; Russell, D.P.; Jiang, Z.Y.; Pellegrini, C.; Wang, X.J.

    1990-01-01

    The Accelerator Test Facility (ATF), presently under construction at Brookhaven National laboratory, is described. It consists of a 50-MeV electron beam synchronizable to a high-peak power CO 2 laser. The interaction of electrons with the laser field will be probed, with some emphasis on exploring laser-based acceleration techniques. 5 refs., 2 figs

  15. Particle-in-cell numerical simulations of a cylindrical Hall thruster with permanent magnets

    Science.gov (United States)

    Miranda, Rodrigo A.; Martins, Alexandre A.; Ferreira, José L.

    2017-10-01

    The cylindrical Hall thruster (CHT) is a propulsion device that offers high propellant utilization and performance at smaller dimensions and lower power levels than traditional Hall thrusters. In this paper we present first results of a numerical model of a CHT. This model solves particle and field dynamics self-consistently using a particle-in-cell approach. We describe a number of techniques applied to reduce the execution time of the numerical simulations. The specific impulse and thrust computed from our simulations are in agreement with laboratory experiments. This simplified model will allow for a detailed analysis of different thruster operational parameters and obtain an optimal configuration to be implemented at the Plasma Physics Laboratory at the University of Brasília.

  16. Superconductivity and future accelerators

    International Nuclear Information System (INIS)

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

    1963-01-01

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

  17. Experimental Evaluation of MHD Generators Operating at High Hall Coefficients

    International Nuclear Information System (INIS)

    Barthelemy, R.R.; Stephan, B.G.; Cooper, R.F.

    1966-01-01

    The experimental evaluation of such open-cycle MHD generator operation, particularly at large values of the Hall parameter and Mach number, is scarce. A flexible combustion-driven MHD generator test facility is being constructed to investigate various generator-operating parameters, generator configurations and designs, and component materials. The plasma source is a combustion chamber in which toluene, or another suitable fuel, is burned with gaseous oxygen diluted with nitrogen. Potassium hydroxide seed is injected with the fuel to produce the necessary plasma conductivity. The gas stream is accelerated in a supersonic nozzle and then flows through the channel. The Hall channel is constructed of water-cooled Inconel rings suitably grooved for the zirconia electrode material. The rings are insulated from each other with Teflon spacers which are shielded from the high temperature gas by a layer of alumina refractory. The channel consists of 54 water-cooled rings assembled in three independent sections. Provisions for instrumentation consist of 15 points for static pressure measurement along the nozzle, channel and diffuser; 20 thermocouple measurements; 3 split rings for transverse current measurements; a voltmeter panel for all 54 electrodes; and all necessary fluid and electrical monitoring instruments. The channel is followed by a diffuser in which some of the dynamic pressure of the gas stream is recovered. The magnet is an iron core design with coils wound of hollow conductor to permit of water-cooling for high power operation. The magnet can operate at field strengths of up to 23 kG. Details of the test programme planned for the generator (commissioning at the end of 1966) are given. (author)

  18. Electron Surfing Acceleration in Magnetic Reconnection

    OpenAIRE

    Hoshino, Masahiro

    2005-01-01

    We discuss that energetic electrons are generated near the X-type magnetic reconnection region due to a surfing acceleration mechanism. In a thin plasma sheet, the polarization electric fields pointing towards the neutral sheet are induced around the boundary between the lobe and plasma sheet in association with the Hall electric current. By using a particle-in-cell simulation, we demonstrate that the polarization electric fields are strongly enhanced in an externally driven reconnection syst...

  19. Valley-chiral quantum Hall state in graphene superlattice structure

    Science.gov (United States)

    Tian, H. Y.; Tao, W. W.; Wang, J.; Cui, Y. H.; Xu, N.; Huang, B. B.; Luo, G. X.; Hao, Y. H.

    2016-05-01

    We theoretically investigate the quantum Hall effect in a graphene superlattice (GS) system, in which the two valleys of graphene are coupled together. In the presence of a perpendicular magnetic field, an ordinary quantum Hall effect is found with the sequence σxy=ν e^2/h(ν=0,+/-1,+/-2,\\cdots) . At the zeroth Hall platform, a valley-chiral Hall state stemming from the single K or K' valley is found and it is localized only on one sample boundary contributing to the longitudinal conductance but not to the Hall conductivity. Our findings may shed light on the graphene-based valleytronics applications.

  20. Accurate micro Hall effect measurements on scribe line pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Wang, Fei

    2009-01-01

    Hall mobility and sheet carrier density are important parameters to monitor in advanced semiconductor production. If micro Hall effect measurements are done on small pads in scribe lines, these parameters may be measured without using valuable test wafers. We report how Hall mobility can...... be extracted from micro four-point measurements performed on a rectangular pad. The dimension of the investigated pad is 400 × 430 ¿m2, and the probe pitches range from 20 ¿m to 50 ¿m. The Monte Carlo method is used to find the optimal way to perform the Hall measurement and extract Hall mobility most...

  1. Intermediate energy nuclear physics at the MIT-Bates linear accelerator Center

    International Nuclear Information System (INIS)

    Alarcon, R.

    2001-01-01

    The MlT-Bates linear accelerator center is a University-based laboratory carrying out frontier research in electromagnetic nuclear physics. The research program is focussed on the flavor structure, charge distribution, shape, size and polarizability of the nucleon; the spin and electromagnetic structure of light nuclei; and the origin of the elements. The Bates research program has three central thrusts: the SAMPLE experiments to probe the flavor structure of the proton using parity-violating electron scattering at back angles; the OOPS (out-of-plane spectrometer system) program which uses out-of-plane detection to probe nucleon and few-body nuclear structure; and the BLAST (Bates large acceptance spectrometer toroid) program which will use a new spectrometer under construction to measure electron scattering from internal gas targets in the south hall ring. (Author)

  2. GRAN SASSO: Reaching the parts that accelerators cannot reach

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    With most of the current experiments at Italy's Gran Sasso Laboratory now well underway, a workshop held earlier this year looked to the future. Gran Sasso was established in the late 1980s to study low rate processes where the laboratory's 1400 metre rock overburden and low natural radioactivity provide an ideal environment. Since then, it has become a major research centre, hosting several international collaborations. The workshop devoted half a day each to four key areas of underground physics, and clearly showed how the non-accelerator approach complements today's accelerator physics achievements. Solar neutrino physics is one of Gran Sasso's main activities, with the Gallex detector half filling one of the laboratory's three experimental halls. Gallex has already made important measurements of the solar neutrino flux, providing first evidence for the proton-proton fusion mechanism which is the solar powerhouse. The next generation experiment, Borexino, will go one step further, measuring the energy distribution of solar neutrinos as well as their flux. The experiment will also be sensitive to neutrino oscillations through its ability to pick out muon and tau neutrinos. Borexino uses boron instead of gallium as the active medium, and is currently in the trial phase. Benchmarking tests with the counter test facility (CTF) have already demonstrated the experiment's feasibility, paving the way for full scale construction. Further ideas for future detectors based on several different active media were also discussed, and a proposal for a helium TPC detector, HELLAZ, was presented. With a threshold of around 240 keV, comparable to that of Gallex and Borexino, HELLAZ would give another handle on neutrinos from the proton-proton reaction, the most abundant source of solar neutrinos. Neutrinoless double beta decay, dark matter searches, and certain low rate processes in nuclear physics all require the quiet, low radiation surroundings

  3. Silicon Carbide (SiC) Power Processing Unit (PPU) for Hall Effect Thrusters

    Science.gov (United States)

    Reese, Bradley

    2015-01-01

    Arkansas Power Electronics International (APEI), Inc., is developing a high-efficiency, radiation-hardened 3.8-kW SiC power supply for the PPU of Hall effect thrusters. This project specifically targets the design of a PPU for the high-voltage Hall accelerator (HiVHAC) thruster, with target specifications of 80- to 160-V input, 200- to 700-V/5A output, efficiency greater than 96 percent, and peak power density in excess of 2.5 kW/kg. The PPU under development uses SiC junction field-effect transistor power switches, components that APEI, Inc., has irradiated under total ionizing dose conditions to greater than 3 MRad with little to no change in device performance.

  4. Hypernuclear spectroscopy via (e,e'K+) in JLab's Hall A

    International Nuclear Information System (INIS)

    LeRose, John J.; Jager, C.W. de; Feuerbach, R.J.; Higinbotham, D.W.; Reitz, B.; Acha, A.; Markowitz, P.; Bydzovsky, P.; Sotona, M.; Chang, C.C.; Cisbani, E.; Cusanno, F.; Frullani, S.; Garibaldi, F.; De Leo, R.; Lagamba, L.; Marrone, S.; Iodice, M.; Urciuoli, G.M.

    2008-01-01

    Results are presented from a new experiment (E94-107) in Hall A of the Thomas Jefferson National Accelerator Facility (JLab) producing 12 Λ B, 16 Λ N, and 9 Λ Li using electroproduction, (e,e ' K + ). In the hypernuclear missing-mass spectrum the experiment achieves very good energy resolution (670 keV FWHM) by exploiting the characteristics of the High Resolution spectrometer pair and the exceptional beam quality available at JLab. The spectrometers were used with the addition of an INFN provided pair of septum magnets to reach the desired small angles. Also, the Hall A standard complement of equipment was further augmented by the addition of a Ring Imaging Cherenkov detector (RICH) to achieve the best possible kaon identification

  5. The Use of Tracer Gas Measurements in Detection and Solution of Indoor Air Quality Problems in a Danish Town Hall

    DEFF Research Database (Denmark)

    Brohus, Henrik; Hyldgård, Carl-Erik

    A Danish town hall with substantial complaints of poor indoor air quality is examined. This paper describes ·the use of traGer gas measurements which form an important part in the detection and solution of the problems. Investigations are carried out both in the field and in the laboratory using...

  6. Electrostatic accelerators

    OpenAIRE

    Hinterberger, F

    2006-01-01

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

  7. Electrostatic accelerators

    CERN Document Server

    Hinterberger, F

    2006-01-01

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

  8. Accelerator development

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

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

  9. Accelerator and Electrodynamics Capability Review

    International Nuclear Information System (INIS)

    Jones, Kevin W.

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  10. Accelerator and electrodynamics capability review

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin W [Los Alamos National Laboratory

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  11. Giant photonic Hall effect in magnetophotonic crystals.

    Science.gov (United States)

    Merzlikin, A M; Vinogradov, A P; Inoue, M; Granovsky, A B

    2005-10-01

    We have considered a simple, square, two-dimensional (2D) PC built of a magneto-optic matrix with square holes. It is shown that using such a magnetophotonic crystal it is possible to deflect a light beam at very large angles by applying a nonzero external magnetic field. The effect is called the giant photonic Hall effect (GPHE) or the magnetic superprism effect. The GPHE is based on magneto-optical properties, as is the photonic Hall effect [B. A. van Tiggelen and G. L. J. A. Rikken, in, edited by V. M. Shalaev (Springer-Verlag, Berlin, 2002), p. 275]; however GPHE is not caused by asymmetrical light scattering but rather by the influence of an external magnetic field on the photonic band structure.

  12. Assessment of elevator rope using Hall Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Lee, Jong Ku [Pukyung National University, Pusan (Korea, Republic of)

    2003-07-01

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4 mm and 1 mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2 mm in depth at 4 mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  13. Assesment of elevator rope using hall sensor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Kim, Jung Woo; Lee, Jong Ku [Pukyong National University, Pusan (Korea, Republic of)

    2003-05-15

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  14. Infinite symmetry in the quantum Hall effect

    Directory of Open Access Journals (Sweden)

    Lütken C.A.

    2014-04-01

    Full Text Available The new states of matter and concomitant quantum critical phenomena revealed by the quantum Hall effect appear to be accompanied by an emergent modular symmetry. The extreme rigidity of this infinite symmetry makes it easy to falsify, but two decades of experiments have failed to do so, and the location of quantum critical points predicted by the symmetry is in increasingly accurate agreement with scaling experiments. The symmetry severely constrains the structure of the effective quantum field theory that encodes the low energy limit of quantum electrodynamics of 1010 charges in two dirty dimensions. If this is a non-linear σ-model the target space is a torus, rather than the more familiar sphere. One of the simplest toroidal models gives a critical (correlation length exponent that agrees with the value obtained from numerical simulations of the quantum Hall effect.

  15. Stuart Hall and Cultural Studies, circa 1983

    Directory of Open Access Journals (Sweden)

    Ann Curthoys

    2017-11-01

    Full Text Available Stuart Hall sought to internationalise theoretical debates and to create Cultural Studies as interdisciplinary. We chart his theoretical journey through a detailed examination of a series of lectures delivered in 1983 and now published for the first time. In these lectures, he discusses theorists such as E.P. Thompson, Raymond Williams, Louis Althusser, Levi Strauss and Antonio Gramsci, and explores the relationship between ideas and social structure, the specificities of class and race, and the legacies of slavery. We note his turn towards metaphors of divergence and dispersal and highlight how autobiographical and deeply personal Hall is in these lectures, especially in his ego histoire moment of traumatic memory recovery.

  16. Hall magnetohydrodynamics: Conservation laws and Lyapunov stability

    International Nuclear Information System (INIS)

    Holm, D.D.

    1987-01-01

    Hall electric fields produce circulating mass flow in confined ideal-fluid plasmas. The conservation laws, Hamiltonian structure, equilibrium state relations, and Lyapunov stability conditions are presented here for ideal Hall magnetohydrodynamics (HMHD) in two and three dimensions. The approach here is to use the remarkable array of nonlinear conservation laws for HMHD that follow from its Hamiltonian structure in order to construct explicit Lyapunov functionals for the HMHD equilibrium states. In this way, the Lyapunov stability analysis provides classes of HMHD equilibria that are stable and whose linearized initial-value problems are well posed (in the sense of possessing continuous dependence on initial conditions). Several examples are discussed in both two and three dimensions

  17. Music hall Markneukirchen; Musikhalle in Markneukirchen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-01-01

    The article presents the new building of the music hall Markneukirchen. From the planned use of the building result very high demands on the ventilation system in order to keep to a sound power level of less than 30 dB(A) in the hall. The building services are dealt with using numerous flowsheets and diagrams: Heat supply, ventilation system, sanitary system, building management, instrumentation and control, electric and lighting systems. (BWI) [Deutsch] Der vorliegende Beitrag stellt den Neubau der Musikhalle Markneukirchen vor. Durch das Nutzungskonzept ergeben sich fuer die Einhaltung eines Schalleistungspegels von weniger als 30 dB(A) im Saalbereich an die Lueftungsanlage sehr hohe Ansprueche. Es werden die raumlufttechnischen Anlagen anhand zahlreicher Flussbilder und Abbildungen vorgestellt: Waermeversorgung, Lueftungstechnik, Sanitaertechnik, Gebaeudeleit- und MSR-Technik, Elektro- und Lichttechnik. (BWI)

  18. Theory of fractional quantum hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1985-08-01

    A theory of the Fractional Quantum Hall Effect is constructed based on magnetic flux fractionization, which lead to instability of the system against selfcompression. A theorem is proved stating that arbitrary potentials fail to lift a specific degeneracy of the Landau level. For the case of 1/3 fractional filling a model 3-particles interaction is constructed breaking the symmetry. The rigid 3-particles wave function plays the role of order parameter. In a BCS type of theory the gap in the single particles spectrum is produced by the 3-particles interaction. The mean field critical behaviour and critical parameters are determined as well as the Ginsburg-Landau equation coefficients. The Hall conductivity is calculated from the first principles and its temperature dependence is found. The simultaneous tunnelling of 3,5,7 etc. electrons and quantum interference effects are predicted. (author)

  19. Coulomb blockade in hierarchical quantum Hall droplets

    International Nuclear Information System (INIS)

    Cappelli, Andrea; Georgiev, Lachezar S; Zemba, Guillermo R

    2009-01-01

    The degeneracy of energy levels in a quantum dot of Hall fluid, leading to conductance peaks, can be readily derived from the partition functions of conformal field theory. Their complete expressions can be found for Hall states with both Abelian and non-Abelian statistics, upon adapting known results for the annulus geometry. We analyze the Abelian states with hierarchical filling fractions, ν = m/(mp ± 1), and find a non-trivial pattern of conductance peaks. In particular, each one of them occurs with a characteristic multiplicity, which is due to the extended symmetry of the m-folded edge. Experimental tests of the multiplicity can shed more light on the dynamics of this composite edge. (fast track communication)

  20. Assessment of elevator rope using Hall Sensor

    International Nuclear Information System (INIS)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo; Lee, Jong Ku

    2003-01-01

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4 mm and 1 mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2 mm in depth at 4 mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  1. Assesment of elevator rope using hall sensor

    International Nuclear Information System (INIS)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo; Lee, Jong Ku

    2003-01-01

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  2. Judy Estes Hall (1940-2015).

    Science.gov (United States)

    Sammons, Morgan T; Boucher, Andrew

    2016-01-01

    Presents an obituary for Judy Estes Hall, who passed away on November 24, 2015. Hall served as the Executive Officer of the National Register of Health Service Psychologists until her retirement in 2013. She is a recognized expert in the development of education and training standards for the profession of psychology, she also made significant contributions in the field of international psychology, where she was a renowned expert in cross-national credentialing and an advocate for commonality in licensing standards. She was the coauthor of one edited volume and author of more than 60 journal articles, book chapters, and professional publications. A passionate advocate for the advancement of women in psychology, a devoted mother and grandmother, a connoisseur of wine and international traveler extraordinaire, she touched the personal and professional lives of many. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  3. Homotopy arguments for quantized Hall conductivity

    CERN Document Server

    Richter, T

    2002-01-01

    Using the strong localization bounds obtained by the Aizenman-Molcanov method for a particle in a magnetic field and a disordered potential, we show that the zero-temperature Hall conductivity of a gas of such particles is quantized and constant as long as both Fermi energy and disorder coupling parameter vary in a region of strong localization of the corresponding two-dimensional phase diagram.

  4. SPS beam to the West Hall

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    One of the two target stations feeding the West Hall (see Annual Report 1976). After the proton beam was split into three branches, the outer two were directed on to targets in the cast iron shielding box, the centre one passing through the box to another target station downstream. Five different targets could be put in each beam, controlled by the mechanism seen on top.

  5. Anomalous hall effect in ferromagnetic semiconductors

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; Niu, Q.; MacDonald, A. H.

    2002-01-01

    Roč. 88, č. 20 (2002), s. 207208-1-207208-4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912; GA MŠk OC P5.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferromagnetic semiconductors * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.323, year: 2002

  6. A hall for assembly and cryogenic tests

    International Nuclear Information System (INIS)

    Beaunier, J.; Buhler, S.; Caruette, A.; Chevrollier, R.; Junquera, T.; Le Scornet, J.C.

    1999-01-01

    Cryodrome, an assembly hall and the testing ground for cryogenic equipment and R and D experiments for the superconducting cavities is going to be transformed for its future missions. The cryogenic utilities, especially the He low pressure pumping capacity, was rearranged and extended to a new area. Space was provided to install CRYHOLAB, a new horizontal cryostat for cavity testing. Automatic control and supervision of the utilities and the experimental area are rebuilt and updated. (authors)

  7. Generic superweak chaos induced by Hall effect

    Science.gov (United States)

    Ben-Harush, Moti; Dana, Itzhack

    2016-05-01

    We introduce and study the "kicked Hall system" (KHS), i.e., charged particles periodically kicked in the presence of uniform magnetic (B ) and electric (E ) fields that are perpendicular to each other and to the kicking direction. We show that for resonant values of B and E and in the weak-chaos regime of sufficiently small nonintegrability parameter κ (the kicking strength), there exists a generic family of periodic kicking potentials for which the Hall effect from B and E significantly suppresses the weak chaos, replacing it by "superweak" chaos (SWC). This means that the system behaves as if the kicking strength were κ2 rather than κ . For E =0 , SWC is known to be a classical fingerprint of quantum antiresonance, but it occurs under much less generic conditions, in particular only for very special kicking potentials. Manifestations of SWC are a decrease in the instability of periodic orbits and a narrowing of the chaotic layers, relative to the ordinary weak-chaos case. Also, for global SWC, taking place on an infinite "stochastic web" in phase space, the chaotic diffusion on the web is much slower than the weak-chaos one. Thus, the Hall effect can be relatively stabilizing for small κ . In some special cases, the effect is shown to cause ballistic motion for almost all parameter values. The generic global SWC on stochastic webs in the KHS appears to be the two-dimensional closest analog to the Arnol'd web in higher dimensional systems.

  8. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.

    2004-01-01

    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  9. Josephson tunneling in bilayer quantum Hall system

    International Nuclear Information System (INIS)

    Ezawa, Z.F.; Tsitsishvili, G.; Sawada, A.

    2012-01-01

    A Bose–Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (−e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ν=1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless. Our results explain recent experiments due to [L. Tiemann, Y. Yoon, W. Dietsche, K. von Klitzing, W. Wegscheider, Phys. Rev. B 80 (2009) 165120] and due to [Y. Yoon, L. Tiemann, S. Schmult, W. Dietsche, K. von Klitzing, Phys. Rev. Lett. 104 (2010) 116802]. We predict also how the critical current changes as the sample is tilted in the magnetic field. -- Highlights: ► Composite bosons undergo Bose–Einstein condensation to form the bilayer quantum Hall state. ► A composite boson is a single electron bound to a flux quantum and carries one unit charge. ► Quantum coherence develops due to the condensation. ► Quantum coherence drives the supercurrent in each layer and the tunneling current. ► There exists the critical input current so that the tunneling current is coherent and dissipationless.

  10. Familial Pallister-Hall in adulthood.

    Science.gov (United States)

    Talsania, Mitali; Sharma, Rohan; Sughrue, Michael E; Scofield, R Hal; Lim, Jonea

    2017-10-01

    Pallister Hall syndrome is autosomal dominant disorder usually diagnosed in infants and children. Current diagnostic criteria include presence of hypothalamic hamartoma, post axial polydactyly and positive family history, but the disease has variable manifestations. Herein we report Pallister Hall syndrome diagnosed in a family where both patients were adults. A 59 year old man developed seizures 4 years prior to our evaluation of him, at which time imaging showed a hypothalamic hamartoma. The seizures were controlled medically. He did well until he had visual changes after a traumatic head injury. Repeat MRI showed slight expansion of the mass with formal visual field testing demonstrating bitemporal hemianopsia. There was no evidence of pituitary dysfunction except for large urine volume. He underwent surgery to debulk the hamartoma and the visual field defects improved. There was no hypopituitarism post-operatively, and the polydyspia resolved. His 29 year old daughter also had seizures and hypothalamic hamartoma. Both patients had had polydactyly with prior surgical correction in childhood. The daughter underwent genetic testing, which revealed a previously undescribed heterozygous single base pair deletion in exon 13 of the GLI3 gene causing a frameshift mutation. Further investigation into family history revealed multiple members in previous generations with polydactyly and/or seizures. Pallister-Hall syndrome is caused by an inherited autosomal dominant or de novo mutation in GLI3 gene. This rare syndrome has not had prevalence defined, however. Generally, diagnoses are made in the pediatric population. Our report adds to the few cases detected in adulthood.

  11. RECIRCULATING ACCELERATION

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  12. LIBO accelerates

    CERN Multimedia

    2002-01-01

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

  13. Accelerating Inspire

    CERN Document Server

    AUTHOR|(CDS)2266999

    2017-01-01

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

  14. US PARTICLE ACCELERATOR SCHOOL: Summer schools

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-11-15

    Continuing it's educational efforts, the US Particle Accelerator School (USPAS) held two summer schools this year. The USPAS has two basic purposes — education in accelerator physics and technology, in particular to train apprentices and update experts; and to encourage US universities and Laboratories to offer programmes in accelerator physics by developing textbooks, training faculty, and organizing schools.

  15. Superconducting magnets technologies for large accelerator

    International Nuclear Information System (INIS)

    Ogitsu, Toru

    2017-01-01

    The first hadron collider with superconducting magnet technologies was built at Fermi National Accelerator Laboratory as TEVATRON. Since then, the superconducting magnet technologies are widely used in large accelerator applications. The paper summarizes the superconducting magnet technologies used for large accelerators. (author)

  16. US PARTICLE ACCELERATOR SCHOOL: Summer schools

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Continuing it's educational efforts, the US Particle Accelerator School (USPAS) held two summer schools this year. The USPAS has two basic purposes — education in accelerator physics and technology, in particular to train apprentices and update experts; and to encourage US universities and Laboratories to offer programmes in accelerator physics by developing textbooks, training faculty, and organizing schools

  17. DC resistance comparison between a current comparator bridge and the quantum Hall system at Inmetro

    International Nuclear Information System (INIS)

    Da Silva, M C; Vasconcellos, R T B; Carvalho, H R

    2016-01-01

    This paper presents a comparison results between the Quantum Hall System (QHS) under development at the Quantum Electrical Metrology Laboratory (Lameq) and the current comparator calibration system, traceable to the Bureau International des Poids et Mesures (BIPM), at the Electrical Standardization Metrology Laboratory (Lampe), both part of the Electrical Metrology Division, at Inmetro. Comparisons were performed with 1 Ω, 10 Ω, 100 Ω, 1 kΩ and 10 kΩ resistors. The results obtained over two years of work are presented here, showing that the comparison contributed to improve the calibration systems of both Lampe and Lameq. (paper)

  18. High luminosity operation of large solid angle scintillator arrays in Jefferson Lab Hall A

    International Nuclear Information System (INIS)

    Ran Shneor

    2003-01-01

    This thesis describes selected aspects of high luminosity operation of large solid angle scintillator arrays in Hall A of the CEBAF (Central Electron Beam Accelerator Facility) at TJNAF (Thomas Jefferson National Accelerator Facility ). CEBAF is a high current, high duty factor electron accelerator with a maximum beam energy of about 6 GeV and a maximum current of 200 (micro)A. Operating large solid angle scintillator arrays in high luminosity environment presents several problems such as high singles rates, low signal to noise ratios and shielding requirements. To demonstrate the need for large solid angle and momentum acceptance detectors as a third arm in Hall A, we will give a brief overview of the physics motivating five approved experiments, which utilize scintillator arrays. We will then focus on the design and assembly of these scintillator arrays, with special focus on the two new detector packages built for the Short Range Correlation experiment E01-015. This thesis also contains the description and results of different tests and calibrations which where conducted for these arrays. We also present the description of a number of tests which were done in order to estimate the singles rates, data reconstruction, filtering techniques and shielding required for these counters

  19. Tandem electrostatic accelerators for BNCT

    International Nuclear Information System (INIS)

    Ma, J.C.

    1994-01-01

    The development of boron neutron capture therapy (BNCT) into a viable therapeutic modality will depend, in part, on the availability of suitable neutron sources compatible with installation in a hospital environment. Low-energy accelerator-based intense neutron sources, using electrostatic or radio frequency quadrupole proton accelerators have been suggested for this purpose and are underdevelopment at several laboratories. New advances in tandem electrostatic accelerator technology now allow acceleration of the multi-milliampere proton beams required to produce therapeutic neutron fluxes for BNCT. The relatively compact size, low weight and high power efficiency of these machines make them particularly attractive for installation in a clinical or research facility. The authors will describe the limitations on ion beam current and available neutron flux from tandem accelerators relative to the requirements for BNCT research and therapy. Preliminary designs and shielding requirements for a tandern accelerator-based BNCT research facility will also be presented

  20. Superconducting accelerator magnet design

    International Nuclear Information System (INIS)

    Wolff, S.

    1994-01-01

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

  1. High performance proton accelerators

    International Nuclear Information System (INIS)

    Favale, A.J.

    1989-01-01

    In concert with this theme this paper briefly outlines how Grumman, over the past 4 years, has evolved from a company that designed and fabricated a Radio Frequency Quadrupole (RFQ) accelerator from the Los Alamos National Laboratory (LANL) physics and specifications to a company who, as prime contractor, is designing, fabricating, assembling and commissioning the US Army Strategic Defense Commands (USA SDC) Continuous Wave Deuterium Demonstrator (CWDD) accelerator as a turn-key operation. In the case of the RFQ, LANL scientists performed the physics analysis, established the specifications supported Grumman on the mechanical design, conducted the RFQ tuning and tested the RFQ at their laboratory. For the CWDD Program Grumman has the responsibility for the physics and engineering designs, assembly, testing and commissioning albeit with the support of consultants from LANL, Lawrence Berkeley Laboratory (LBL) and Brookhaven National laboratory. In addition, Culham Laboratory and LANL are team members on CWDD. LANL scientists have reviewed the physics design as well as a USA SDC review board. 9 figs

  2. ACCELERATOR SCHOOL: Casting light

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-07-15

    A booming spinoff from high energy physics is the synchrotron radiation sector which exploits the intense radiation given off when beams of charged particles are bent. With particle physics and the applications of synchrotron radiation very different, and with new dedicated laboratories being built for the latter, there is a natural tendency for the two communities to drift apart. However a step in the other direction came with the course 'Synchrotron Radiation and Free Electron Lasers' organized by the CERN Accelerator School (CAS) and the Daresbury Laboratory, held in Chester, UK.

  3. FMIT accelerator

    International Nuclear Information System (INIS)

    Armstrong, D.D.

    1983-01-01

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

  4. Electron accelerator

    International Nuclear Information System (INIS)

    Abramyan.

    1981-01-01

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

  5. Commemorative Symposium on the Hall Effect and its Applications

    CERN Document Server

    Westgate, C

    1980-01-01

    In 1879, while a graduate student under Henry Rowland at the Physics Department of The Johns Hopkins University, Edwin Herbert Hall discovered what is now universally known as the Hall effect. A symposium was held at The Johns Hopkins University on November 13, 1979 to commemorate the lOOth anniversary of the discovery. Over 170 participants attended the symposium which included eleven in­ vited lectures and three speeches during the luncheon. During the past one hundred years, we have witnessed ever ex­ panding activities in the field of the Hall effect. The Hall effect is now an indispensable tool in the studies of many branches of condensed matter physics, especially in metals, semiconductors, and magnetic solids. Various components (over 200 million!) that utilize the Hall effect have been successfully incorporated into such devices as keyboards, automobile ignitions, gaussmeters, and satellites. This volume attempts to capture the important aspects of the Hall effect and its applications. It includes t...

  6. Experimental test of 200 W Hall thruster with titanium wall

    Science.gov (United States)

    Ding, Yongjie; Sun, Hezhi; Peng, Wuji; Xu, Yu; Wei, Liqiu; Li, Hong; Li, Peng; Su, Hongbo; Yu, Daren

    2017-05-01

    We designed a 200 W Hall thruster based on the technology of pushing down a magnetic field with two permanent magnetic rings. Boron nitride (BN) is an important insulating wall material for Hall thrusters. The discharge characteristics of the designed Hall thruster were studied by replacing BN with titanium (Ti). Experimental results show that the designed Hall thruster can discharge stably for a long time under a Ti channel. Experiments were performed to determine whether the channel and cathode are electrically connected. When the channel wall and cathode are insulated, the divergence angle of the plume increases, but the performance of the Hall thruster is improved in terms of thrust, specific impulse, anode efficiency, and thrust-to-power ratio. Ti exhibits a powerful antisputtering capability, a low emanation rate of gas, and a large structural strength, making it a potential candidate wall material in the design of low-power Hall thrusters.

  7. Development and characterization of high-efficiency, high-specific impulse xenon Hall thrusters

    Science.gov (United States)

    Hofer, Richard Robert

    This dissertation presents research aimed at extending the efficient operation of 1600 s specific impulse Hall thruster technology to the 2000--3000 s range. While recent studies of commercially developed Hall thrusters demonstrated greater than 4000 s specific impulse, maximum efficiency occurred at less than 3000 s. It was hypothesized that the efficiency maximum resulted as a consequence of modern magnetic field designs, optimized for 1600 s, which were unsuitable at high-specific impulse. Motivated by the industry efforts and mission studies, the aim of this research was to develop and characterize xenon Hall thrusters capable of both high-specific impulse and high-efficiency operation. The research divided into development and characterization phases. During the development phase, the laboratory-model NASA-173M Hall thrusters were designed with plasma lens magnetic field topographies and their performance and plasma characteristics were evaluated. Experiments with the NASA-173M version 1 (v1) validated the plasma lens design by showing how changing the magnetic field topography at high-specific impulse improved efficiency. Experiments with the NASA-173M version 2 (v2) showed there was a minimum current density and optimum magnetic field topography at which efficiency monotonically increased with voltage. Between 300--1000 V, total specific impulse and total efficiency of the NASA-173Mv2 operating at 10 mg/s ranged from 1600--3400 s and 51--61%, respectively. Comparison of the thrusters showed that efficiency can be optimized for specific impulse by varying the plasma lens design. During the characterization phase, additional plasma properties of the NASA-173Mv2 were measured and a performance model was derived accounting for a multiply-charged, partially-ionized plasma. Results from the model based on experimental data showed how efficient operation at high-specific impulse was enabled through regulation of the electron current with the magnetic field. The

  8. Two-fluid electromagnetic simulations of plasma-jet acceleration with detailed equation-of-state

    International Nuclear Information System (INIS)

    Thoma, C.; Welch, D. R.; Clark, R. E.; Bruner, N.; MacFarlane, J. J.; Golovkin, I. E.

    2011-01-01

    We describe a new particle-based two-fluid fully electromagnetic algorithm suitable for modeling high density (n i ∼ 10 17 cm -3 ) and high Mach number laboratory plasma jets. In this parameter regime, traditional particle-in-cell (PIC) techniques are challenging due to electron timescale and lengthscale constraints. In this new approach, an implicit field solve allows the use of large timesteps while an Eulerian particle remap procedure allows simulations to be run with very few particles per cell. Hall physics and charge separation effects are included self-consistently. A detailed equation of state (EOS) model is used to evolve the ion charge state and introduce non-ideal gas behavior. Electron cooling due to radiation emission is included in the model as well. We demonstrate the use of these new algorithms in 1D and 2D Cartesian simulations of railgun (parallel plate) jet accelerators using He and Ar gases. The inclusion of EOS and radiation physics reduces the electron temperature, resulting in higher calculated jet Mach numbers in the simulations. We also introduce a surface physics model for jet accelerators in which a frictional drag along the walls leads to axial spreading of the emerging jet. The simulations demonstrate that high Mach number jets can be produced by railgun accelerators for a variety of applications, including high energy density physics experiments.

  9. Two-fluid electromagnetic simulations of plasma-jet acceleration with detailed equation-of-state

    Energy Technology Data Exchange (ETDEWEB)

    Thoma, C.; Welch, D. R.; Clark, R. E.; Bruner, N. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); MacFarlane, J. J.; Golovkin, I. E. [Prism Computational Sciences, Inc., Madison, Wisconsin 53711 (United States)

    2011-10-15

    We describe a new particle-based two-fluid fully electromagnetic algorithm suitable for modeling high density (n{sub i} {approx} 10{sup 17} cm{sup -3}) and high Mach number laboratory plasma jets. In this parameter regime, traditional particle-in-cell (PIC) techniques are challenging due to electron timescale and lengthscale constraints. In this new approach, an implicit field solve allows the use of large timesteps while an Eulerian particle remap procedure allows simulations to be run with very few particles per cell. Hall physics and charge separation effects are included self-consistently. A detailed equation of state (EOS) model is used to evolve the ion charge state and introduce non-ideal gas behavior. Electron cooling due to radiation emission is included in the model as well. We demonstrate the use of these new algorithms in 1D and 2D Cartesian simulations of railgun (parallel plate) jet accelerators using He and Ar gases. The inclusion of EOS and radiation physics reduces the electron temperature, resulting in higher calculated jet Mach numbers in the simulations. We also introduce a surface physics model for jet accelerators in which a frictional drag along the walls leads to axial spreading of the emerging jet. The simulations demonstrate that high Mach number jets can be produced by railgun accelerators for a variety of applications, including high energy density physics experiments.

  10. Presentations from the Second ORION Workshop, Stanford Linear Accelerator Center, February 18-20, 2003

    International Nuclear Information System (INIS)

    Noble, Robert

    2003-01-01

    ORION will be a dedicated user facility available for experimental research in plasma and laser acceleration of particles, beam-plasma physics, ultra-short pulse electron and radiation sources, and potentially laboratory astrophysics. It will bring together a diverse collection of researchers motivated to solve some of the most complex and fascinating problems in these fields. The ORION Facility will be based on the Next Linear Collider Test Accelerator (NLCTA), an existing accelerator at SLAC capable of producing 60 to 350 MeV electron beams. The NLCTA will be augmented with a new photo-injector source, two experimental halls, extraction beamlines, a user laser room, and a data acquisition area. Facility construction is anticipated to start in October 2003, and first beam for experiments is planned for 2005. A central goal of ORION is to provide a facility responsive to the research needs of its users. The workshop's purpose is to explore the range of experiments envisioned by potential users and review the types of beams available and the desired beam parameters. This workshop is an opportunity for the research community to provide input on the facility's test beams, layout, shared diagnostic equipment, simulation and computing capabilities, and user support infrastructure. Results from the workshop will go into determining the facility's design as well as help the SLAC management plan for future user needs on the site once operations begin

  11. Neutrino physics and accelerators

    International Nuclear Information System (INIS)

    Kaftanov, V.

    1978-01-01

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

  12. Acceleration theorems

    International Nuclear Information System (INIS)

    Palmer, R.

    1994-06-01

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

  13. Study of a new possibility to predict the behavior of high - performance anticorrosive protections applied on steel after their exposure in natural aggressive environments, respectively in laboratory accelerated conditions

    Directory of Open Access Journals (Sweden)

    Irina POPA

    2014-12-01

    Full Text Available As a result of the global warming, notable changes in the climatic regime of Romania were observed in the last 40-50 years by increasing of the maximum temperatures and decreasing of the minimum temperatures characteristic for each season. This paper makes reference to an experimental research regarding the actual severity of the Romanian climate and its effects toward some performant anticorrosive coatings applied on steel. Such performant anticorrosive protection systems were exposed in situ – marine and alpine environment - and in parallel, aiming to simulate the severe climatic actions through laboratory accelerated environments - neutral salt fog, condensation and temperature variations. The graphical representation and the interpretation of the adhesion to the steel surface by means of the variation of the class into which the paint was framed after performing the cross-cut test during the exposure provided information concerning a new possibility to predict the evolution of the degradation of the paint, by means of this characteristic experimentally determined.

  14. An experimental investigation of the internal magnetic field topography of an operating Hall thruster

    International Nuclear Information System (INIS)

    Peterson, Peter Y.; Gallimore, Alec D.; Haas, James M.

    2002-01-01

    Magnetic field measurements were made in the discharge channel of the 5 kW-class P5 laboratory-model Hall thruster to investigate what effect the Hall current has on the static, applied magnetic field topography. The P5 was operated at 1.6 and 3.0 kW with a discharge voltage of 300 V. A miniature inductive loop probe (B-Dot probe) was employed to measure the radial magnetic field profile inside the discharge channel of the P5 with and without the plasma discharge. These measurements are accomplished with minimal disturbance to thruster operation with the High-speed Axial Reciprocating Probe system. The results of the B-Dot probe measurements indicate a change in the magnetic field topography from that of the vacuum field measurements. The measured magnetic field profiles are then examined to determine the possible nature and source of the difference between the vacuum and plasma magnetic field profiles

  15. Iodine Hall Thruster Propellant Feed System for a CubeSat

    Science.gov (United States)

    Polzin, Kurt A.; Peeples, Steven

    2014-01-01

    The components required for an in-space iodine vapor-fed Hall effect thruster propellant management system are described. A laboratory apparatus was assembled and used to produce iodine vapor and control the flow through the application of heating to the propellant reservoir and through the adjustment of the opening in a proportional flow control valve. Changing of the reservoir temperature altered the flowrate on the timescale of minutes while adjustment of the proportional flow control valve changed the flowrate immediately without an overshoot or undershoot in flowrate with the requisite recovery time associated with thermal control systems. The flowrates tested spanned a range from 0-1.5 mg/s of iodine, which is sufficient to feed a 200-W Hall effect thruster.

  16. LINEAR ACCELERATOR

    Science.gov (United States)

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

    1959-02-17

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

  17. Pelletron accelerator at Panjab University Chandigarh

    International Nuclear Information System (INIS)

    Singh, Nirmal; Mehta, Devinder

    2006-01-01

    The purpose of pelletron accelerator at Panjab University is to develop a low-energy accelerator laboratory within the university infrastructure. It will be housing a tandem electrostatic accelerator. The facility will bring together the available scientific expertise from a wide range of applications, viz. medical, biological and physical sciences and engineering that utilize accelerator-based technologies and techniques. It will play an important role in promoting integrated research and education across scientific disciplines available in the campus. (author)

  18. LINAC for ADS application - accelerator technologies

    International Nuclear Information System (INIS)

    Garnett, Robert W.; Sheffreld, Richard L.

    2009-01-01

    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.

  19. Hall Sensor Output Signal Fault-Detection & Safety Implementation Logic

    Directory of Open Access Journals (Sweden)

    Lee SangHun

    2016-01-01

    Full Text Available Recently BLDC motors have been popular in various industrial applications and electric mobility. Recently BLDC motors have been popular in various industrial applications and electric mobility. In most brushless direct current (BLDC motor drives, there are three hall sensors as a position reference. Low resolution hall effect sensor is popularly used to estimate the rotor position because of its good comprehensive performance such as low cost, high reliability and sufficient precision. Various possible faults may happen in a hall effect sensor. This paper presents a fault-tolerant operation method that allows the control of a BLDC motor with one faulty hall sensor and presents the hall sensor output fault-tolerant control strategy. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. There are a few research work on hall effect sensor failure of BLDC motor. The conventional fault diagnosis methods are signal analysis, model based analysis and knowledge based analysis. The proposed method is signal based analysis using a compensation signal for reconfiguration and therefore fault diagnosis can be fast. The proposed method is validated to execute the simulation using PSIM.

  20. The Hall module of an exact category with duality

    OpenAIRE

    Young, Matthew B.

    2012-01-01

    We construct from a finitary exact category with duality a module over its Hall algebra, called the Hall module, encoding the first order self-dual extension structure of the category. We study in detail Hall modules arising from the representation theory of a quiver with involution. In this case we show that the Hall module is naturally a module over the specialized reduced sigma-analogue of the quantum Kac-Moody algebra attached to the quiver. For finite type quivers, we explicitly determin...

  1. DESIGN OF SUBSOIL IMPROVEMENT BELOW HALL FLOORS

    Directory of Open Access Journals (Sweden)

    Peter Turček

    2017-10-01

    Full Text Available The construction of an industrial park is now being prepared near the town of Nitra. The investor fixed very strict conditions for the bearing capacity and, above all, the settlement of halls and their floors. The geological conditions at the construction site are difficult: there are soft clay soils with high compressibility and low bearing capacity. A detailed analysis of soil improvement was made. Stone columns were prepared to be fitted into an approximately 5 m thick layer of soft clay. The paper shows the main steps used in the design of the stone columns.

  2. Optically induced Hall effect in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M; Gray, E Mac A, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)

    2009-03-01

    We describe an experiment which investigates the effect of a longitudinal electric field on the spin-polarized carriers generated by a circularly polarized light in semiconductors. Our experiment observes the effect as a Hall voltage resulting from nonequilibrium magnetization induced by the spin-carrier electrons accumulating at the transverse boundaries of the sample as a result of asymmetries in scattering for spin-up and spin-down electrons in the presence of spin-orbit interaction. It is found that the effect depends on the longitudinal electric field and doping density as well as on temperature. The results are presented by discussing the dominant spin relaxation mechanisms in semiconductors.

  3. Fractional quantization and the quantum hall effect

    International Nuclear Information System (INIS)

    Guerrero, J.; Calixto, M.; Aldaya, V.

    1998-01-01

    Quantization with constrains is considered in a group-theoretical framework, providing a precise characterization of the set of good operators, i.e., those preserving the constrained Hilbert space, in terms of the representation of the subgroup of constraints. This machinery is applied to the quantization of the torus as symplectic manifold, obtaining that fractional quantum numbers are permitted, provided that we allow for vector valued representations. The good operators turn out to be the Wilson loops and, for certain representations of the subgroup of constraints, the modular transformations. These results are applied to the Fractional Quantum Hall Effect, where interesting implications are derived

  4. Excitons in the Fractional Quantum Hall Effect

    Science.gov (United States)

    Laughlin, R. B.

    1984-09-01

    Quasiparticles of charge 1/m in the Fractional Quantum Hall Effect form excitons, which are collective excitations physically similar to the transverse magnetoplasma oscillations of a Wigner crystal. A variational exciton wavefunction which shows explicitly that the magnetic length is effectively longer for quasiparticles than for electrons is proposed. This wavefunction is used to estimate the dispersion relation of these excitons and the matrix elements to generate them optically out of the ground state. These quantities are then used to describe a type of nonlinear conductivity which may occur in these systems when they are relatively clean.

  5. A Compton polarimeter for CEBAF Hall A

    Energy Technology Data Exchange (ETDEWEB)

    Bardin, G; Cavata, C; Frois, B; Juillard, M; Kerhoas, S; Languillat, J C; Legoff, J M; Mangeot, P; Martino, J; Platchkov, S; Rebourgeard, P; Vernin, P; Veyssiere, C; CEBAF Hall A Collaboration

    1994-09-01

    The physic program at CEBAF Hall A includes several experiments using 4 GeV polarized electron beam: parity violation in electron elastic scattering from proton and {sup 4}He, electric form factor of the proton by recoil polarization, neutron spin structure function at low Q{sup 2}. Some of these experiments will need beam polarization measurement and monitoring with an accuracy close to 4%, for beam currents ranging from 100 nA to 100 microA. A project of a Compton Polarimeter that will meet these requirements is presented. It will comprise four dipoles and a symmetric cavity consisting of two identical mirrors. 1 fig., 10 refs.

  6. Hall conductivity for two dimensional magnetic systems

    International Nuclear Information System (INIS)

    Desbois, J.; Ouvry, S.; Texier, C.

    1996-01-01

    A Kubo inspired formalism is proposed to compute the longitudinal and transverse dynamical conductivities of an electron in a plane (or a gas of electrons at zero temperature) coupled to the potential vector of an external local magnetic field, with the additional coupling of the spin degree of freedom of the electron to the local magnetic field (Pauli Hamiltonian). As an example, the homogeneous magnetic field Hall conductivity is rederived. The case of the vortex at the origin is worked out in detail. A perturbative analysis is proposed for the conductivity in the random magnetic impurity problem (Poissonian vortices in the plane). (author)

  7. ORNL pellet acceleration program

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  8. Linear accelerator development at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Batchelor, K.

    1976-01-01

    A description is given of operating experience on the 200 MeV Proton Injector Linace of the A.G.S. emphasizing developments in field phase and amplitude control and beam diagnostics. Developments in auxilliary use of the machine are also described

  9. Linear accelerator development at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Batchelor, K.

    1976-01-01

    This paper describes the operating experience on the 200 MeV proton injector linac of the A.G.S. emphasizing developments in field phase and amplitude control and beam diagnostics. Developments in auxilliary use of the machine are also described. (author)

  10. Cylindrical Hall Thrusters with Permanent Magnets

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.

    2010-01-01

    The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT.

  11. Bimetric Theory of Fractional Quantum Hall States

    Directory of Open Access Journals (Sweden)

    Andrey Gromov

    2017-11-01

    Full Text Available We present a bimetric low-energy effective theory of fractional quantum Hall (FQH states that describes the topological properties and a gapped collective excitation, known as the Girvin-Macdonald-Platzman (GMP mode. The theory consists of a topological Chern-Simons action, coupled to a symmetric rank-2 tensor, and an action à la bimetric gravity, describing the gapped dynamics of a spin-2 mode. The theory is formulated in curved ambient space and is spatially covariant, which allows us to restrict the form of the effective action and the values of phenomenological coefficients. Using bimetric theory, we calculate the projected static structure factor up to the k^{6} order in the momentum expansion. To provide further support for the theory, we derive the long-wave limit of the GMP algebra, the dispersion relation of the GMP mode, and the Hall viscosity of FQH states. The particle-hole (PH transformation of the theory takes a very simple form, making the duality between FQH states and their PH conjugates manifest. We also comment on the possible applications to fractional Chern insulators, where closely related structures arise. It is shown that the familiar FQH observables acquire a curious geometric interpretation within the bimetric formalism.

  12. Hypernuclear Spectroscopy at JLab Hall C

    International Nuclear Information System (INIS)

    Hashimoto, Osamu; Chiba, Atsushi; Doi, Daisuke; Fujii, Yu; Toshiyuki, Gogami; Kanda, Hiroki; Kaneta, M.; Kawama, Daisuke; Maeda, Kazushige; Maruta, Tomofumi; Matsumura, Akihiko; Nagao, Sho; Nakamura, Satoshi; Shichijo, Ayako; Tamura, Hirokazu; Taniya, Naotaka; Yamamoto, Taku; Yokota, Kosuke; Kato, S.; Sato, Yoshinori; Takahashi, Toshiyuki; Noumi, Hiroyuki; Motoba, T.; Hiyama, E.; Albayrak, Ibrahim; Ates, Ozgur; Chen, Chunhua; Christy, Michael; Keppel, Cynthia; Kohl, Karl; Li, Ya; Liyanage, Anusha Habarakada; Tang, Liguang; Walton, T.; Ye, Zhihong; Yuan, Lulin; Zhu, Lingyan; Baturin, Pavlo; Boeglin, Werner; Dhamija, Seema; Markowitz, Pete; Raue, Brian; Reinhold, Joerg; Hungerford, Ed; Ent, Rolf; Fenker, Howard; Gaskell, David; Horn, Tanja; Jones, Mark; Smith, Gregory; Vulcan, William; Wood, Stephen; Johnston, C.; Simicevic, Neven; Wells, Stephen; Samanta, Chhanda; Hu, Bitao; Shen, Ji; Wang, W.; Zhang, Xiaozhuo; Zhang, Yi; Feng, Jing; Fu, Y.; Zhou, Jian; Zhou, S.; Jiang, Yi; Lu, H.; Yan, Xinhu; Ye, Yunxiu; Gan, Liping; Ahmidouch, Abdellah; Danagoulian, Samuel; Gasparian, Ashot; Elaasar, Mostafa; Wesselmann, Frank; Asaturyan, Arshak; Margaryan, Amur; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Tadevosyan, Vardan; Androic, Darko; Furic, Miroslav; Petkovic, Tomislav; Seva, Tomislav; Niculescu, Gabriel; Niculescu, Maria-Ioana; Rodriguez, Victor; Cisbani, Evaristo; Cusanno, Francesco; Garibaldi, Franco; Urciuoli, Guido; De Leo, Raffaele; Maronne, S.; Achenbach, Carsten; Pochodzalla, J.

    2010-01-01

    Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e(prime)K + ) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e(prime)K + ) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the 'Tilt method' was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7 ΛHe and 28 ΛAl together with that of 12 ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7 Li, 9 Be, 10 B, 12 C and 52 Cr as well as with those of CH 2 and H 2 O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.

  13. Bimetric Theory of Fractional Quantum Hall States

    Science.gov (United States)

    Gromov, Andrey; Son, Dam Thanh

    2017-10-01

    We present a bimetric low-energy effective theory of fractional quantum Hall (FQH) states that describes the topological properties and a gapped collective excitation, known as the Girvin-Macdonald-Platzman (GMP) mode. The theory consists of a topological Chern-Simons action, coupled to a symmetric rank-2 tensor, and an action à la bimetric gravity, describing the gapped dynamics of a spin-2 mode. The theory is formulated in curved ambient space and is spatially covariant, which allows us to restrict the form of the effective action and the values of phenomenological coefficients. Using bimetric theory, we calculate the projected static structure factor up to the k6 order in the momentum expansion. To provide further support for the theory, we derive the long-wave limit of the GMP algebra, the dispersion relation of the GMP mode, and the Hall viscosity of FQH states. The particle-hole (PH) transformation of the theory takes a very simple form, making the duality between FQH states and their PH conjugates manifest. We also comment on the possible applications to fractional Chern insulators, where closely related structures arise. It is shown that the familiar FQH observables acquire a curious geometric interpretation within the bimetric formalism.

  14. Undulator Hall Air Temperature Fault Scenarios

    International Nuclear Information System (INIS)

    Sevilla, J.

    2010-01-01

    Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about ±2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

  15. Review of Advanced Accelerator Concepts R & D in Japan

    Science.gov (United States)

    Kitagawa, Yoneyoshi; Uesaka, Mitsuru; Koyama, Kazuyoshi; Nakajima, Kaszuhisa; Tajima, Toshiki; Daido, Hiroyuki; Ogata, Atsushi; Nemoto, Koshichi; Nishida, Yasushi; Yugami, Noboru; Miyamoto, Shuji; Dobashi, Katsuhiro

    2004-12-01

    More than 15 Japanese laboratories are dedicated to the advanced and compact accelerator development. Some use ultra-intense lasers and others use microwave concepts. As for the laser electron accleration, the topics are the capillary acceleration and the mono-energetic acceleration. The laser ion acceleration is also active. As well, the compatization is proceeding of the current rf accelerator. The National Institute for Radiological Science is promoting an advanced accelerator concept project mainly for the medical application.

  16. Accelerator microanalysis

    International Nuclear Information System (INIS)

    Tuniz, C.

    1997-01-01

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

  17. A periodic plasma waveguide accelerator

    International Nuclear Information System (INIS)

    Cole, F.T.

    1985-01-01

    The increasing cost of synchrotrons and storage rings has given new interest in the search for new methods of acceleration. The primary goal of this search is very large accelerating fields, because the cost of an accelerator to reach TeV energies is dominated by costs that scale with length. Very large electric fields are possible in plasmas and in lasers and many geometries are being studied that make use of plasmas, lasers, or combinations of them. In a plasma accelerator, the plasma can have several different functions. It may act as a medium for the propagation of accelerating electric-field waves. In addition, these waves may also act as a source of the energy needed to accelerate particles. Accelerators using various waves in plasmas have been built and studied in many laboratories. The device proposed here is an attempt to separate the two functions of providing a medium and providing an energy source. A relatively low-energy electron beam is used as a non-neutral plasma only to make a slow-wave medium for the propagation of an externally generated wave. The wave is a TM electromagnetic wave and the device may be thought of as a conventional electron linear accelerator with the evacuated volume and metallic envelope replaced by the electron beam. A separate second beam, which may be electrons or heavier particles, is accelerated. The application in mind here is a single-pass collider

  18. Mary E. Hall: Dawn of the Professional School Librarian

    Science.gov (United States)

    Alto, Teresa

    2012-01-01

    A century ago, a woman named Mary E. Hall convinced school leaders of the need for the professional school librarian--a librarian who cultivated a love of reading, academic achievement, and independent learning skills. After graduating from New York City's Pratt Institute Library School in 1895, Hall developed her vision for the high school…

  19. What is the Hallé? | Smith | Philosophical Papers

    African Journals Online (AJOL)

    The bulk of the paper examines the difficulty of reconciling the view that the Hallé is several individuals with two prima facie plausible theses about the manner of its persistence through time. The paper is structured around some remarks made by Peter Simons about groups, and the Hallé in particular, in his Parts.

  20. Spin hall effect associated with SU(2) gauge field

    Science.gov (United States)

    Tao, Y.

    2010-01-01

    In this paper, we focus on the connection between spin Hall effect and spin force. Here we investigate that the spin force due to spin-orbit coupling, which, in two-dimensional system, is equivalent to forces of Hirsch and Chudnovsky besides constant factors 3 and frac{3}{2} respectively, is a part of classic Anandan force, and that the spin Hall effect is an anomalous Hall effect. Furthermore, we develop the method of AC phase to derive the expression for the spin force, and note that the most basic spin Hall effect indeed originate from the AC phase and is therefore an intrinsic quantum mechanical property of spin. This method differs from approach of Berry phase in the study of anomalous Hall effect , which is the intrinsic property of the perfect crystal. On the other hand, we use an elegant skill to show that the Chudnovsky-Drude model is reasonable. Here we have improved the theoretical values of spin Hall conductivity of Chudnovsky. Compared to the theoretical values of spin Hall conductivity in the Chudnovsky-Drude model, ours are in better agreement with experimentation. Finally, we discuss the relation between spin Hall effect and fractional statistics.