Joint Actinide Shock Physics Experimental Research (JASPER) Facility Overview

International Nuclear Information System (INIS)

Konrad, C.H.; Braddy, R.W.; Martinez, Mark

2001-01-01

The JASPER Facility will utilize a Two-Stage Light Gas Gun to conduct equation-of-state (EOS) experiments of plutonium and other special nuclear materials. The overall facility will be discussed with emphasis on the Two-Stage Light Gas Gun characteristics and mission. The primary and secondary containment systems that were developed for this project will be presented. Primary gun diagnostics and timing will also be discussed

Study and development of a two-stage light gas gun

International Nuclear Information System (INIS)

Lezaud, Jean-Michel

1976-01-01

After recalling the definition of principal dimensional internal characteristics of a light gas gun studied and developed at Commissariat a l'Energie Atomique, we present the interior ballistics calculation systems in fixed working conditions: these conditions permit to accelerate a 400 g projectile to 6500 m/s speed. About these conditions is studied the influence of some operating parameters: weight of piston, initial pressure of hydrogen, breaking pressure of diaphragms. Afterwards is presented a study of dynamic axial stresses. The consequence of these stresses in certain cross sections of gun has led to conceive the original solution of gun called gun sliding launching tube. At last, some special points appropriated to operating or working methods (optimisation of convergent, extrusion of piston, failure of diaphragms, position of target, circuits of fluids) are presented. (author) [fr

Plasma target output from a magnetically augmented, gas-injected, washer-stack plasma gun

International Nuclear Information System (INIS)

Osher, J.E.

1982-01-01

This article describes a new washer-stack gun design developed for the application of plasma target production for the startup of neutral-beam trapping in a fusion research magnetic confinement system. The gun is a Mo anode type that is D 2 injected and has an auxiliary pulsed magnet for control of plasma-flux mapping. One of the principal features of 2--10-ms duration pulses for gun operation in a suitable magnetic field is the formation of an arc column along magnetic field lines from the gun's central cathode electrode to the vacuum chamber walls (at common anode potential). The primary power output from a 5.0-cm-i.d. gun is typically carried along this arc column by a stream of approximately 2000 A of 50--250-eV electrons. This primary stream of relatively low-density energetic electrons efficiently ionizes the injected gas, forming a quasi-dc source of denser secondary plasma of approx.10 13 /cm 3 at a few eV, which is able to flow or diffuse away along a somewhat larger column of magnetic field lines. In plasma-target production tests on a test stand, a gun operated at a D 2 gas flow of 22 Torr ls -1 yielded 250 A of equivalent plasma flow

Results of the AFWL deflagration gun experiments

International Nuclear Information System (INIS)

Hackett, K.E.; Baker, W.L.; Beason, J.D.

1987-01-01

The snowplow and deflagration modes of coaxial plasma gun operation have been experimentally investigated and computationally simulated at the Air Force Weapons Laboratory. The snowplow mode occurs when the gun is prefilled to a uniform gas density. The initial breakdown forms near the insulator at the gun breech. It heats the gas and creates a shock wave that travels down the gun, ionizing gas and producing a thin current sheath that travels just behind the shock front. The shock front piles up the gas in front of itself as it moves down the gun - hence the name ''snowplow''. Deflagration occurs when gas is injected into an evacuated gun so that the initial breakdown forms as the gas fills the gun. The ionized gas is accelerated into the vacuum region carrying current and magnetic field with it. A quasi-stationary diffuse discharge develops. Gas still entering the gun is processed through the deflagrating discharge and accelerated out the gun muzzle

Joint Actinide Shock Physics Experimental Research (JASPER) Facility Update

International Nuclear Information System (INIS)

Conrad, C. H.; Miller, J.; Cowan, M.; Martinez, M.; Whitcomb, B.

2003-01-01

The JASPER Facility utilizes a Two-Stage Light Gas Gun to conduct equation-of-state(EOS) experiments on plutonium and other special nuclear materials. The overall facility will be discussed with emphasis on the Two-Stage Light Gas Gun characteristics and control interfaces and containment. The containment systems that were developed for this project will be presented

Use of a two-stage light-gas gun as an injector for electromagnetic railguns

International Nuclear Information System (INIS)

Shahinpoor, M.

1989-01-01

Ablation of wall materials is known to be a major factor limiting the performance of railguns. To minimize this effect, it is desirable too inject projectiles into railgun at velocities greater than the ablation threshold velocity (6-8 km/s for copper rails). Because two-stage light-gas guns are capable of achieving such velocities, a program was initiated to design, build and evaluate the performance of a two-stage light gas gun, utilizing hydrogen gas, for use as an injector to an electromagnetic railgun. This effort is part of a project to develop a hypervelocity electromagnetic launcher (HELEOS) for use in equation-of-state studies. In this paper, the specific design features that enhance compatibility of the injector with the railgun, including a slip-joint between the injector launch tube and the coupling section to the railgun are described. The operational capabilities for using all major projectile velocity measuring techniques, such as in-bore pressure gauges, laser and CW x-ray interrupt techniques, flash x-ray and continuous in-bore velocity measurements using VISAR interferometry are also discussed. Finally an internal ballistics code for optimizing gun performance has been utilized to interpret performance data of the gun

Simplified pipe gun

International Nuclear Information System (INIS)

Sorensen, H.; Nordskov, A.; Sass, B.; Visler, T.

1987-01-01

A simplified version of a deuterium pellet gun based on the pipe gun principle is described. The pipe gun is made from a continuous tube of stainless steel and gas is fed in from the muzzle end only. It is indicated that the pellet length is determined by the temperature gradient along the barrel right outside the freezing cell. Velocities of around 1000 m/s with a scatter of +- 2% are obtained with a propellant gas pressure of 40 bar

Compressed gas combined single- and two-stage light-gas gun

Science.gov (United States)

Lamberson, L. E.; Boettcher, P. A.

2018-02-01

With more than 1 trillion artificial objects smaller than 1 μm in low and geostationary Earth orbit, space assets are subject to the constant threat of space debris impact. These collisions occur at hypervelocity or speeds greater than 3 km/s. In order to characterize material behavior under this extreme event as well as study next-generation materials for space exploration, this paper presents a unique two-stage light-gas gun capable of replicating hypervelocity impacts. While a limited number of these types of facilities exist, they typically are extremely large and can be costly and dangerous to operate. The design presented in this paper is novel in two distinct ways. First, it does not use a form of combustion in the first stage. The projectile is accelerated from a pressure differential using air and inert gases (or purely inert gases), firing a projectile in a nominal range of 1-4 km/s. Second, the design is modular in that the first stage sits on a track sled and can be pulled back and used in itself to study lower speed impacts without any further modifications, with the first stage piston as the impactor. The modularity of the instrument allows the ability to investigate three orders of magnitude of impact velocities or between 101 and 103 m/s in a single, relatively small, cost effective instrument.

A light-gas gun for acceleration of pellets of solid D2

International Nuclear Information System (INIS)

Nordskov, A.; Skovgaard, H.; Soerensen, H.; Weisberg, K.V.

1980-10-01

A gun has been designed and built to be used for injecting solid D 2 pellets into a small tokamak for pellet-plasma interaction studies. The pellets are formed and accelerated at temperatures close to those of liquid helium. They are propelled with pressurised H 2 -gas; the pressure arises when a quantity of solid H 2 placed in the gun barrel behind the pellet is pulse heated. Pellet velocities up to 240 m/s have been obtained. The directional accuracy is better than 0.2deg and the repetition rate is one firing every five minutes. The pellet volume is 0.6 mm 3 (2 x 10 19 molecules) while the quantity of propeller gas used is around 12 x 10 19 molecules. (author)

Gas powered fluid gun with recoil mitigation

Science.gov (United States)

Grubelich, Mark C; Yonas, Gerold

2013-11-12

A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

Integration of the PHIN RF Gun into the CLIC Test Facility

CERN Document Server

Döbert, Steffen

2006-01-01

CERN is a collaborator within the European PHIN project, a joint research activity for Photo injectors within the CARE program. A deliverable of this project is an rf Gun equipped with high quantum efficiency Cs2Te cathodes and a laser to produce the nominal beam for the CLIC Test Facility (CTF3). The nominal beam for CTF3 has an average current of 3.5 A, 1.5 GHz bunch repetition frequency and a pulse length of 1.5 ìs (2332 bunches) with quite tight stability requirements. In addition a phase shift of 180 deg is needed after each train of 140 ns for the special CLIC combination scheme. This rf Gun will be tested at CERN in fall 2006 and shall be integrated as a new injector into the CTF3 linac, replacing the existing injector consisting of a thermionic gun and a subharmonic bunching system. The paper studies the optimal integration into the machine trying to optimize transverse and longitudinal phase space of the beam while respecting the numerous constraints of the existing accelerator. The presented scheme...

6D Phase Space Measurements at the SLAC Gun Test Facility

CERN Document Server

Schmerge, J

2003-01-01

Proposed fourth generation light sources using SASE FELs to generate short pulse, coherent X-rays require demonstration of high brightness electron sources. The Gun Test Facility (GTF) at SLAC was built to test high brightness sources for the proposed Linac Coherent Light Source at SLAC. The GTF is composed of an Sband photocathode rf gun with a Cu cathode, emittance compensating solenoid, single 3 m SLAC linac section and e-beam diagnostic section with a UV drive laser system. The longitudinal emittance exiting the gun has been determined by measuring the energy spectrum downstream of the linac as a function of the linac phase. The e-beam pulse width, correlated and uncorrelated energy spread at the linac entrance have been fit to the measured energy spectra using a least square error fitting routine. The fit yields a pulse width of 2.9 ps FWHM for a 4.3 ps FWHM laser pulse width and 2% rms correlated energy spread with 0.07% rms uncorrelated energy spread. The correlated energy spread is enhanced in the lin...

Heavy duty plasma spray gun

International Nuclear Information System (INIS)

Irons, G.C.; Klein, J.F.; Lander, R.D.; Thompson, H.C.; Trapani, R.D.

1984-01-01

A heavy duty plasma spray gun for extended industrial service is disclosed. The gun includes a gas distribution member made of a material having a coefficient of expansion different from that of the parts surrounding it. The gas distribution member is forcibly urged by a resilient member such as a coiled spring against a seal so as to assure the plasma gas is introduced into the gun arc in a manner only defined by the gas distribution member. The gun has liquid cooling for the nozzle (anode) and the cathode. Double seals are provided between the coolant and the arc region and a vent is provided between the seals which provides an indication when a seal has failed. Some parts of the gun are electrically isolated from others by an intermediate member which is formed as a sandwich of two rigid metal face pieces and an insulator disposed between them. The metal face pieces provide a rigid body to attach the remaining parts in proper alignment therewith

Two-dimensional computational modeling of high-speed transient flow in gun tunnel

Science.gov (United States)

Mohsen, A. M.; Yusoff, M. Z.; Hasini, H.; Al-Falahi, A.

2018-03-01

In this work, an axisymmetric numerical model was developed to investigate the transient flow inside a 7-meter-long free piston gun tunnel. The numerical solution of the gun tunnel was carried out using the commercial solver Fluent. The governing equations of mass, momentum, and energy were discretized using the finite volume method. The dynamic zone of the piston was modeled as a rigid body, and its motion was coupled with the hydrodynamic forces from the flow solution based on the six-degree-of-freedom solver. A comparison of the numerical data with the theoretical calculations and experimental measurements of a ground-based gun tunnel facility showed good agreement. The effects of parameters such as working gases and initial pressure ratio on the test conditions in the facility were examined. The pressure ratio ranged from 10 to 50, and gas combinations of air-air, helium-air, air-nitrogen, and air-CO2 were used. The results showed that steady nozzle reservoir conditions can be maintained for a longer duration when the initial conditions across the diaphragm are adjusted. It was also found that the gas combination of helium-air yielded the highest shock wave strength and speed, but a longer test time was achieved in the test section when using the CO2 test gas.

The Ames Vertical Gun Range

Science.gov (United States)

Karcz, J. S.; Bowling, D.; Cornelison, C.; Parrish, A.; Perez, A.; Raiche, G.; Wiens, J.-P.

2016-01-01

The Ames Vertical Gun Range (AVGR) is a national facility for conducting laboratory- scale investigations of high-speed impact processes. It provides a set of light-gas, powder, and compressed gas guns capable of accelerating projectiles to speeds up to 7 km s(exp -1). The AVGR has a unique capability to vary the angle between the projectile-launch and gravity vectors between 0 and 90 deg. The target resides in a large chamber (diameter approximately 2.5 m) that can be held at vacuum or filled with an experiment-specific atmosphere. The chamber provides a number of viewing ports and feed-throughs for data, power, and fluids. Impacts are observed via high-speed digital cameras along with investigation-specific instrumentation, such as spectrometers. Use of the range is available via grant proposals through any Planetary Science Research Program element of the NASA Research Opportunities in Space and Earth Sciences (ROSES) calls. Exploratory experiments (one to two days) are additionally possible in order to develop a new proposal.

Experimental studies of coaxial plasma gun current

International Nuclear Information System (INIS)

Price, D.W.

1988-01-01

In this investigation of a coaxial plasma gun, plasma sheath currents and related behavior are examined. Plasma behavior in the gun affects gun characteristics. Plasma gun applications are determined by the plasma behavior. The AFWL PUFF capacitor bank (72 μF, 29 nH, 120 kV) drives the plasma gun using a deuterium fill gas. The gas breakdown site is isolated from the dielectric/vacuum interface in the AFWL system. Two gas values deliver gas in the system. The first delivers gas from the gun breech and the second optional valve delivers gas to the gun muzzle. Currents and voltages are measured by Rogowski coils, B probes and capacitive voltage probes. A O-D slug model is used to predict the current, inductance, gun voltage and plasma sheath velocity. The slug model assumes the sheath transits the gun with all mass in the sheath. In the snowplow mode, the plasma sheath is thin with a sharp current rise and drop. Our system operated in a transition mode between the snowplow and deflagration modes with early snowplow behavior and late deflagration behavior. Neutrons are produced in a plasma pinch at the gun muzzle, indicating snowplow behavior. The slug theory models overall gun behavior to experimental accuracy. Experimental results are compared to four theories for plasma sheath velocities: the Alfven collisionally limited model, the Rosenbluth model, the Fishbine saturated model and a single particle drift model. Experimental velocities vary from 10 5 to 10 6 m/s. Only the single particle drift and the slug model calculations are of the right magnitude (8 x 10 5 m/s). The Fishbine and the Rosenbluth models predict slower velocities (2 x 10 5 m/s). The Alfven model is not applicable to this system

Review of gas gun technology with emphasis on fusion fueling applications

International Nuclear Information System (INIS)

Flagg, R.F.

1978-01-01

A review is made of current light gas gun and related hyper-velocity launcher technology with emphasis on physical and technological limits, advantages, and disadvantages as they apply to injection requirements for refueling Tokamak type nuclear fusion reactors. It is shown that the mass and velocity requirements for refueling are well within the capabilities of the state of the art and can be produced by several of the different types of gun/launching devices. The practical problems of adapting this performance capability to the refueling task are addressed and some possible configurations are given including both single pellet and multiple pellet injection. A short bibliography is given for those who wish additional detailed information

Ignition Features of Plasma-Beam Discharge in Gas-Discharge Electron Gun Operation

Directory of Open Access Journals (Sweden)

Valery A. Tutyk

2013-01-01

Full Text Available The current paper presents the results of experimental researches to determine the mode features of plasma-beam discharge (PBD generation by an electron beam injected by a low-vacuum gasdischarge electron gun (LGEG with the cold cathode and hollow anode on the basis of the high-voltage glow discharge and in the range of helium pressure of P ? 10 ÷ 130 Pa. The PBD boundaries and their dependences on parameters of an electron beam are found. The influence of PBD on parameters of low-vacuum gas-discharge electron gun is revealed. It causes an avalanche increase of electron beam current and burning of plasma-beam discharge in the whole space of the vacuum chamber volume and generation of electromagnetic radiation is revealed. Achieved results will be used for implementation of various vacuum technologies in the medium of reaction gas and generated electromagnetic radiation.

Electron gun for SSRF

International Nuclear Information System (INIS)

Sheng Shugang; Lin Guoqiang; Gu Qiang; Li Deming

2003-01-01

A 100 kV triode-electron-gun has been designed and manufactured for the Linac of Shanghai Synchrotron Radiation Facility (SSRF). In this paper the performance of the gun and some key components are described

A cold cathode of a gas-discharge electron-ion gun

International Nuclear Information System (INIS)

1974-01-01

A cold cathode of a gas-discharge electron-ion gun is constructed in order to continuously replace the eroded material by feeding a wire or a set of coaxial cylinders in the spot where the ions hit the cathode. In this way, the form of the cathode and the electric-field configuration is preserved which guarantees the conservation of a sharp narrow electron beam profile

Beam dynamics simulations in the photo-cathode RF gun for the CLIC test facility

International Nuclear Information System (INIS)

Marchand, P.; Rinolfi, L.

1992-01-01

The CERN CLIC Test Facility (CTF) uses an RF gun with a laser driven photo-cathode in order to generate electron pulses of high charge (≥10 nC) and short duration (≤20 ps). The RF gun consists of a 3 GHz 1 + 1/2 cell cavity based on the design originally proposed at BNL which minimizes the non-linearities in the transverse field. The beam dynamics in the cavity is simulated by means of the multiparticle tracking code PARMELA. The results are compared to previous simulations as well as to the first experimental data. (author). 4 refs., 4 tabs., 4 figs

Coaxial Plasma Gun Development for the ARPA-E PLX- α Project

Science.gov (United States)

Witherspoon, F. Douglas; Case, Andrew; Brockington, Samuel

2015-11-01

We describe the renewed effort to design and build coaxial plasma guns appropriate for a scaling study of spherically imploding plasma liners as a standoff magneto-inertial-fusion driver under the ARPA-E Accelerating Low-Cost Plasma Heating And Assembly (ALPHA) program. HyperV joins LANL, UAH, UNM, BNL, and Tech-X to develop, build, operate and analyze a 60 plasma gun experiment using the existing PLX facility at LANL. The guns will be designed to operate over a scaling range of operating parameters: 0.5-5.0 mg of Ar, Ne, N2, Kr, and Xe; 20-60 km/s; 1016 -1017 cm-3 muzzle density; and up to 7.5 kJ stored energy per gun. Each gun is planned to incorporate contoured gaps, fast dense gas injection and triggering, and innovative integral sparkgap switching and pfn configurations to reduce inductance, cost, and complexity, and to increase efficiency and system reliability. We will describe the overall design approach for the guns and pulsed power systems. This work supported by the ARPA-E ALPHA Program.

A method for predicting the impact velocity of a projectile fired from a compressed air gun facility

International Nuclear Information System (INIS)

Attwood, G.J.

1988-03-01

This report describes the development and use of a method for calculating the velocity at impact of a projectile fired from a compressed air gun. The method is based on a simple but effective approach which has been incorporated into a computer program. The method was developed principally for use with the Horizontal Impact Facility at AEE Winfrith but has been adapted so that it can be applied to any compressed air gun of a similar design. The method has been verified by comparison of predicted velocities with test data and the program is currently being used in a predictive manner to specify test conditions for the Horizontal Impact Facility at Winfrith. (author)

NASA-Ames vertical gun

Science.gov (United States)

Schultz, P. H.

1984-01-01

A national facility, the NASA-Ames vertical gun range (AVGR) has an excellent reputation for revealing fundamental aspects of impact cratering that provide important constraints for planetary processes. The current logistics in accessing the AVGR, some of the past and ongoing experimental programs and their relevance, and the future role of this facility in planetary studies are reviewed. Publications resulting from experiments with the gun (1979 to 1984) are listed as well as the researchers and subjects studied.

Development of a novel thermionic RF electron gun applied on a compact THz-FEL facility

Science.gov (United States)

Hu, T. N.; Pei, Y. J.; Qin, B.; Liu, K. F.; Feng, G. Y.

2018-04-01

The current requirements from civil and commercial applications lead to the development of compact free-electron laser (FEL)-based terahertz (THz) radiation sources. A picosecond electron gun plays an important role in an FEL-THz facility and attracts significant attention, as machine performance is very sensitive to initial conditions. A novel thermionic gun with an external cathode (EC) and two independently tunable cavities (ITCs) has been found to be a promising alternative to conventional electron sources due to its remarkable characteristics, and correspondingly an FEL injector can achieve a balance between a compact layout and high brightness benefitting from the velocity bunching properties and RF focusing effects in the EC-ITC gun. Nevertheless, the EC-ITC gun has not been extensively examined as part of the FEL injector in the past years. In this regard, to fill this gap, a development focusing on the experimental setup of an FEL injector based on an EC-ITC gun is described in detail. Before assembly, dynamic beam simulations were performed to investigate the optimal mounting position for the Linac associated with the focusing coils, and a suitable radio-frequency (RF) system was established based on a power coupling design and allocation. The testing bench proved to be fully functional through basic experiments using typical diagnostic approaches for estimating primary parameters. Associated with dynamic beam calculations, a performance evaluation for an EC-ITC gun was established while providing indirect testing results for an FEL injector.

Particle transport and gas feed during gun injection

International Nuclear Information System (INIS)

Fowler, T K.

1999-01-01

It is shown that ion and neutral transport during gun injection tends to equalize the density in the spheromak to that in the open-line current channel. Since a gun operating at or near the ion saturation current requires a minimum density, because of transport these gun requirements also determine a minimum density in the spheromak that increases as the field increases. Hence attaining high fields by gun injection sets lower limits on the density, which in turn limits the temperature of the plasma and increases its ohmic resistance. Estimates of these effects are given using 0-D models calibrated to CTX, as guidance to 2-D UEDGE calculations in progress. For gun power levels in SSPX and the Pulsed Spheromak reactor, we find that buildup persists to the highest field levels of interest

Use of a Tantalum Liner to Reduce Bore Erosion and Increase Muzzle Velocity in Two-Stage Light Gas Guns

Science.gov (United States)

Bogdanoff, David W.

2015-01-01

Muzzle velocities and gun erosion predicted by earlier numerical simulations of two stage light gas guns with steel gun tubes were in good agreement with experimental values. In a subsequent study, simulations of high performance shots were repeated with rhenium (Re) gun tubes. Large increases in muzzle velocity (2 - 4 km/sec) were predicted for Re tubes. In addition, the hydrogen-produced gun tube erosion was, in general, predicted to be zero with Re tubes. Tantalum (Ta) has some mechanical properties superior to those of Re. Tantalum has a lower modulus of elasticity than Re for better force transmission from the refractory metal liner to an underlying thick wall steel tube. Tantalum also has greater ductility than Re for better survivability during severe stress/strain cycles. Also, tantalum has been used as a coating or liner in military powder guns with encouraging results. Tantalum has, however, somewhat inferior thermal properties to those of rhenium, with a lower melting point and lower density and thermal conductivity. The present study was undertaken to see to what degree the muzzle velocity gains of rhenium gun tubes (over steel tubes) could be achieved with tantalum gun tubes. Nine high performance shots were modeled with a new version of our CFD gun code for steel, rhenium and tantalum gun tubes. For all except the highest velocity shot, the results with Ta tubes were nearly identical with those for Re tubes. Even for the highest velocity shot, the muzzle velocity gain over a steel tube using Ta was 82% of the gain obtained using Re. Thus, the somewhat inferior thermal properties of Ta (when compared to those of Re) translate into only very slightly poorer overall muzzle velocity performance. When this fact is combined with the superior mechanical properties of Ta and the encouraging performance of Ta liners/coatings in military powder guns, tantalum is to be preferred over Re as a liner/coating material for two stage light gas guns to increase muzzle

Chlorobenzylidenemalonitrile Gas Exposure from A Novelty Personal-Protection Gun

Directory of Open Access Journals (Sweden)

Dong, Christopher

2007-05-01

Full Text Available We present an unusual case of chlorobenzylidenemalonitrile (CS tear-gas exposure from the unwitting discharge of a personal-protection handgun loaded with CS gas. The gun was in a bag of toys purchased from a local thrift store and was discharged by a child. The responding paramedic presumptively identified the substance as CS based solely on personal experience. This recognition led to suboptimal field management of the incident with the paramedic failing to follow the standard operating procedures for an unknown chemical exposure. As this was a benign agent, there were no serious consequences. This case highlights the pre-hospital and emergency department challenges associated with the management of an unknown chemical exposure and the potential consequences if the chemical is a toxic substance. A methodical approach following established protocols can reduce the potential for negative outcomes. Review of the literature found no other report of CS gas exposure from such a personal-protection weapon.

Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

Energy Technology Data Exchange (ETDEWEB)

Fan, D.; Luo, S. N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Huang, J. W.; Zeng, X. L.; Li, Y.; E, J. C.; Huang, J. Y. [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Sun, T.; Fezzaa, K. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Wang, Z. [Physics Division P-25, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-05-15

We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantify lattice deformation and fracture; fracture is dominated by splitting cracks followed by wing cracks, and diffraction peaks are broadened likely due to mosaic spread. Our results demonstrate the potential of such multiscale measurements for studying high strain-rate phenomena at dynamic extremes.

Compact streak camera for the shock study of solids by using the high-pressure gas gun

Science.gov (United States)

Nagayama, Kunihito; Mori, Yasuhito

1993-01-01

For the precise observation of high-speed impact phenomena, a compact high-speed streak camera recording system has been developed. The system consists of a high-pressure gas gun, a streak camera, and a long-pulse dye laser. The gas gun installed in our laboratory has a muzzle of 40 mm in diameter, and a launch tube of 2 m long. Projectile velocity is measured by the laser beam cut method. The gun is capable of accelerating a 27 g projectile up to 500 m/s, if helium gas is used as a driver. The system has been designed on the principal idea that the precise optical measurement methods developed in other areas of research can be applied to the gun study. The streak camera is 300 mm in diameter, with a rectangular rotating mirror which is driven by an air turbine spindle. The attainable streak velocity is 3 mm/microsecond(s) . The size of the camera is rather small aiming at the portability and economy. Therefore, the streak velocity is relatively slower than the fast cameras, but it is possible to use low-sensitivity but high-resolution film as a recording medium. We have also constructed a pulsed dye laser of 25 - 30 microsecond(s) in duration. The laser can be used as a light source of observation. The advantage for the use of the laser will be multi-fold, i.e., good directivity, almost single frequency, and so on. The feasibility of the system has been demonstrated by performing several experiments.

QUICKGUN: An algorithm for estimating the performance of two-stage light gas guns

International Nuclear Information System (INIS)

Milora, S.L.; Combs, S.K.; Gouge, M.J.; Kincaid, R.W.

1990-09-01

An approximate method is described for solving the equation of motion of a projectile accelerated by a two-stage light gas gun that uses high-pressure (<100-bar) gas from a storage reservoir to drive a piston to moderate speed (<400 m/s) for the purpose of compressing the low molecular weight propellant gas (hydrogen or helium) to high pressure (1000 to 10,000 bar) and temperature (1000 to 10,000 K). Zero-dimensional, adiabatic (isentropic) processes are used to describe the time dependence of the ideal gas thermodynamic properties of the storage reservoir and the first and second stages of the system. A one-dimensional model based on an approximate method of characteristics, or wave diagram analysis, for flow with friction (nonisentropic) is used to describe the nonsteady compressible flow processes in the launch tube. Linear approximations are used for the characteristic and fluid particle trajectories by averaging the values of the flow parameters at the breech and at the base of the projectile. An assumed functional form for the Mach number at the breech provides the necessary boundary condition. Results of the calculation are compared with data obtained from two-stage light gas gun experiments at Oak Ridge National Laboratory for solid deuterium and nylon projectiles with masses ranging from 10 to 35 mg and for projectile speeds between 1.6 and 4.5 km/s. The predicted and measured velocities generally agree to within 15%. 19 refs., 3 figs., 2 tabs

Bagheera: A new experimental facility at Cea / Valduc for actinides studies under high dynamic loading

International Nuclear Information System (INIS)

Roy, G.; Llorca, F.; Lanier, G.; Lamalle, S.; Beaulieu, J.; Antoine, P.; Martinuzzi, P.

2006-01-01

This paper is a technical presentation about a new experimental facility recently developed at CEA/Valduc, BAGHEERA, a French acronym for 'Hopkinson And High Speed Experiments Glove Box'. This facility is used since mid-2003 to characterize the physical and mechanical behaviour of actinides under high dynamic loadings. For this purpose, four basic experimental devices are confined inside a single 10 m long, 3 m high and 1.5 m large glove box: a 50 mm bore diameter single stage light gas gun, two compression and torsion split Hopkinson bars (SHPB and TSHB respectively) and a Taylor test device (TTD). A unique highly automated system drives all devices. The overall architecture of the facility takes into account the useful ability to carry out symmetrical and reverse experiments with the gas gun, that is actinide to actinide impact and actinide to inert material impact. Design and technical data on the experimental equipment are addressed, with a particular emphasis on the gas gun specific features due to actinide applications

ION GUN

Science.gov (United States)

Dandl, R.A.

1961-10-24

An ion gun is described for the production of an electrically neutral ionized plasma. The ion gun comprises an anode and a cathode mounted in concentric relationship with a narrow annulus between. The facing surfaces of the rear portions of the anode and cathode are recessed to form an annular manifold. Positioned within this manifold is an annular intermediate electrode aligned with the an nulus between the anode and cathode. Gas is fed to the manifold and an arc discharge is established between the anode and cathode. The gas is then withdrawn from the manifold through the annulus between the anode and cathode by a pressure differential. The gas is then ionized by the arc discharge across the annulus. The ionized gas is withdrawn from the annulus by the combined effects of the pressure differential and a collimating magnetic field. In a 3000 gauss magnetic field, an arc voltage of 1800 volts, and an arc current of 0.2 amp, a plasma of about 3 x 10/sup 11/ particles/cc is obtained. (AEC)

Armature formation in a railgun using a two-stage light-gas gun injector

International Nuclear Information System (INIS)

Hawke, R.S.; Susoeff, A.R.; Asay, J.R.; Hall, C.A.; Konrad, C.H.; Hickman, R.J.; Sauve, J.L.

1989-01-01

During the past decade several research groups have tried to achieve reliable acceleration of projectiles to velocities in excess of 8 km/s by using a railgun. All attempts have met with difficulties. However, in the past four years the researchers have come to agree on the nature and causes of the difficulties. The consensus is that the hot plasma armature - used to commutate across the rails and to accelerate the projectile - causes ablation of the barrel wall; this ablation ultimately results in parasitic secondary arc formation through armature separation and/or restrike. The subsequence deprivation of current to the propulsion armature results in a limit to the achievable projectile velocity. Methods of mitigating the process are under study. One method uses a two-stage light-gas gun as a preaccelerator/injector to the railgun. The gas gun serves a double purpose: It quickly accelerates the projectile to a high velocity, and it fills the barrel behind the propulsive armature with insulating gas. While this approach is expected to improve railgun performance, it also requires development of techniques to form the propulsive armature behind the projectile in the high-velocity, high-pressure gas stream. This paper briefly summarizes the problems encountered in attempts to achieve hypervelocities with a railgun. Included is a description of the phenomenology and details of joint Sandia National Laboratories, Albuquerque/Lawrence Livermore National Laboratory (SNLA/LNLL) work at SNLA on a method for forming the needed plasma armature

Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode

OpenAIRE

Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.

2010-01-01

Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma def...

Marshall Space Flight Center's Impact Testing Facility Capabilities

Science.gov (United States)

Finchum, Andy; Hubbs, Whitney; Evans, Steve

2008-01-01

Marshall Space Flight Center s (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960s, then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California. The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility s unique capabilities were deemed a "National Asset" by the DoD. The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas guns, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

RF gun using laser-triggered photocathode

International Nuclear Information System (INIS)

Akiyama, H.; Otake, Y.; Naito, T.; Takeuchi, Y.; Yoshioka, M.

1992-01-01

An RF gun using laser-triggered photocathode has many advantages as an injector of the linear colliders since it can generate a low emittance and high current pulsed beam. The experimental facility for the RF gun, such as an RF system, a laser system and a photocathode have been fabricated to study the fundamental characteristics. The dynamics of the RF gun has also studied by the 1D sheet beam model. (author)

Investigation of pellet acceleration by an arc heated gas gun

International Nuclear Information System (INIS)

Andersen, S.A.; Baekmark, L.; Jensen, V.O.; Michelsen, P.; Weisberg, K.V.

1988-10-01

This report describes work on pellet acceleration by means of an arc heated gas gun. Preliminary results were described in Riso-M-2536 and in Riso-M-2650. This final report describes the work carried out from 1987.03.31 to 1988.09.30. An arc heated hydrogen gas source, for pneumatic acceleration of deuterium pellets to velocities above 2 km/s, was developed. Experiments were performed with an arc chamber to which different methods of hydrogen supply were possible, and to which the input of electrical power could be programmed. Results in terms of pressure transients and acceleration curves are presented. Maximum pellet velocities approaching 2 km/s were obtained. This limit is discussed in relation to the presented data. Finally this report contains a summary and a conclusion for the entire project. (author) 34 ills., 3 refs

Investigation of pellet acceleration by an arc heated gas gun

International Nuclear Information System (INIS)

Andersen, P.; Andersen, S.A.; Bundgaard, J.; Baekmark, L.; Hansen, B.H.; Jensen, V.O.; Kossek, H.; Michelsen, P.K.; Nordskov, A.; Sass, B.; Soerensen, H.; Weisberg, K.V.

1987-06-01

This report describes work on pellet acceleration by means of an arc heated gas gun. The work is a continuation of the work described in RISO-M-2536. The aim of the work is to obtain velocities well above 2 km/s for 3.2 mm diameter deuterium pellets. By means of a cryogenic arc chamber in which the hydrogen propellant is pre-condensed, extruded deutetrium pellets are accelerated up to a maximum velocity of 1.93 km/s. When increasing the energy input to the arc in order to increase the pellet velocity further the heat input to the extrusion/punching pellet loading mechanism was found to be critical: preparation of pellets became difficult and cooling times between shots became inconveniently long. In order to circumvent this problems the concept of a room temperature hydrogen propellant pellet fed arc chamber was proposed. Preliminary results from acceleration of polyurethane pellets with this arc chamber are described as well as the work of developing of feed pellet guns for this chamber. Finally the report describes design consideration for a high pressure propellant pellet fed arc chamber together with preliminary results obtained with a proto-type arc chamber. (author)

Gun Dynamics Laboratory

Data.gov (United States)

Federal Laboratory Consortium — The Gun Dynamics Laboratory is a research multi-task facility, which includes two firing bays, a high bay area and a second floor laboratory space. The high bay area...

Design of a Two-Stage Light Gas Gun for Muzzle Velocities of 10 - 11 kms

Science.gov (United States)

Bogdanoff, David W.

2016-01-01

Space debris poses a major risk to spacecraft. In low earth orbit, impact velocities can be 10 11 kms and as high as 15 kms. For debris shield design, it would be desirable to be able to launch controlled shape projectiles to these velocities. The design of the proposed 10 11 kmsec gun uses, as a starting point, the Ames 1.280.22 two stage gun, which has achieved muzzle velocities of 10 11.3 kmsec. That gun is scaled up to a 0.3125 launch tube diameter. The gun is then optimized with respect to maximum pressures by varying the pump tube length to diameter ratio (LD), the piston mass and the hydrogen pressure. A pump tube LD of 36.4 is selected giving the best overall performance. Piezometric ratios for the optimized guns are found to be 2.3, much more favorable than for more traditional two stage light gas guns, which range from 4 to 6. The maximum powder chamber pressures are 20 to 30 ksi. To reduce maximum pressures, the desirable range of the included angle of the cone of the high pressure coupling is found to be 7.3 to 14.6 degrees. Lowering the break valve rupture pressure is found to lower the maximum projectile base pressure, but to raise the maximum gun pressure. For the optimized gun with a pump tube LD of 36.4, increasing the muzzle velocity by decreasing the projectile mass and increasing the powder loads is studied. It appears that saboted spheres could be launched to 10.25 and possibly as high as 10.7 10.8 kmsec, and that disc-like plastic models could be launched to 11.05 kms. The use of a tantalum liner to greatly reduce bore erosion and increase muzzle velocity is discussed. With a tantalum liner, CFD code calculations predict muzzle velocities as high as 12 to 13 kms.

Exhaust gas processing facility

International Nuclear Information System (INIS)

Terada, Shin-ichi.

1995-01-01

The facility of the present invention comprises a radioactive liquid storage vessel, an exhaust gas dehumidifying device for dehumidifying gases exhausted from the vessel and an exhaust gas processing device for reducing radioactive materials in the exhaust gases. A purified gas line is disposed to the radioactive liquid storage vessel for purging exhaust gases generated from the radioactive liquid, then dehumidified and condensed liquid is recovered, and exhaust gases are discharged through an exhaust gas pipe disposed downstream of the exhaust gas processing device. With such procedures, the scale of the exhaust gas processing facility can be reduced and exhaust gases can be processed efficiently. (T.M.)

Joule-Thomson effect in a Pierce electron gun

International Nuclear Information System (INIS)

Batalin, V.A.

1982-01-01

A model which can be investigated both by means of the system of Vlasov equations and by means of ideal gas state equation is proposed for evaluation of emittance growth in the Pierce electron gun of electron beam with the limiting small distribution rate and intended for electron cooling facilities. The assumption has been made that transverse emittance growth is different from the zero. Thermodynamical approach to the problem of electron beam propagation permits to evaluate the increase of its emittance. It is shown that the increase of the electron beam emittance in the Pierce electron gun is similar to Joule-Thompson effect for gases. The effect increases with the decrease of the beam initial temperature. The increase of the emittance can become essential even in hte perfect (without aberration) Pierce optics at beam transverse temperature of the order of 0.1 eV

Improvement of pump tubes for gas guns and shock tube drivers

Science.gov (United States)

Bogdanoff, D. W.

1990-01-01

In a pump tube, a gas is mechanically compressed, producing very high pressures and sound speeds. The intensely heated gas produced in such a tube can be used to drive light gas guns and shock tubes. Three concepts are presented that have the potential to allow substantial reductions in the size and mass of the pump tube to be achieved. The first concept involves the use of one or more diaphragms in the pump tube, thus replacing a single compression process by multiple, successive compressions. The second concept involves a radical reduction in the length-to-diameter ratio of the pump tube and the pump tube piston. The third concept involves shock heating of the working gas by high explosives in a cyclindrical geometry reusable device. Preliminary design analyses are performed on all three concepts and they appear to be quite feasible. Reductions in the length and mass of the pump tube by factors up to about 11 and about 7, respectively, are predicted, relative to a benchmark conventional pump tube.

Gas supply planning for new gas-fired electricity generation facilities

International Nuclear Information System (INIS)

Slocum, J.C.

1990-01-01

This paper explores several key issues in gas supply planning for new gas fired electric generation facilities. This paper will have two main sections, as follows: developing the gas supply plan for a gas-fired electricity generation facility and exploring key gas supply contract pricing issues

Mechanical design of a RF electron gun

International Nuclear Information System (INIS)

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

1989-01-01

Brookhaven National Laboratory is building an Accelerator Test Facility at which we plan to study laser acceleration of electrons, inverse free electron lasers and the production of X-rays by non-linear Compton scattering. The facility contains an electron gun, linac, lasers and ancillary systems which will enable the production of 6 ps duration pulses of 50-100 MeV electrons. The electron source is an one and one half cell RF Electron gun which utilizes either a thermionic or photoemissive cathode to produce 5 MeV electrons. This paper discusses how gun mechanical design considerations such as material, vacuum maintenance, surface finish, fabrication methods, cavity tuning, and cathode replacement were reconciled to arrive at the final design. 9 refs., 2 figs., 2 tabs

Mechanical design of a rf electron gun

International Nuclear Information System (INIS)

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

1988-01-01

Brookhaven National Laboratory is building an Accelerator Test Facility at which we plan to study laser acceleration of electrons inverse free electron lasers and the production of X-rays by non- linear Compton scattering. The facility contains an electron gun, linac, lasers and ancillary systems which will enable the production of 6 ps duration pulses of 50--100 MeV electrons. The electron source is an one and one half cell RF Electron gun which utilizes either a thermionic or photoemissive cathode to produce 5 MeV electrons. This paper discusses how gun mechanical design considerations such as material, vacuum maintenance, surface finish, fabrication methods, cavity tuning, and cathode replacement were reconciled to arrive at the final design. 9 refs., 2 figs., 2 tabs

Plasma-gun fueling for tokamak reactors

International Nuclear Information System (INIS)

Ehst, D.A.

1980-11-01

In light of the uncertain extrapolation of gas puffing for reactor fueling and certain limitations to pellet injection, the snowplow plasma gun has been studied as a fueling device. Based on current understanding of gun and plasma behavior a design is proposed, and its performance is predicted in a tokamak reactor environment

Progress on Using NEA Cathodes in an RF Gun

CERN Document Server

Fliller, Raymond P; Blüm, Hans; Edwards, Helen; Hüning, Markus; Schultheiss, Tom; Sinclair, Charles K

2005-01-01

RF guns have proven useful in multiple accelerator applications, and are an attractive electron source for the ILC. Using a NEA GaAs photocathode in such a gun allows for the production of polarized electron beams. However the lifetime of a NEA cathode in this environment is reduced by ion and electron bombardment and residual gas oxidation. We report progress made with studies to produce a RF gun using a NEA GaAs photocathode to produce polarized electron beams. Attempts to reduce the residual gas pressure in the gun are discussed. Initial measurements of ion flux through the cathode port are compared with simulations of ion bombardment. Future directions are also discussed.

LCLS Gun Solenoid Design Considerations

International Nuclear Information System (INIS)

Schmerge, John

2010-01-01

The LCLS photocathode rf gun requires a solenoid immediately downstream for proper emittance compensation. Such a gun and solenoid have been operational at the SSRL Gun Test Facility (GTF) for over eight years. Based on magnetic measurements and operational experience with the GTF gun solenoid multiple modifications are suggested for the LCLS gun solenoid. The modifications include adding dipole and quadrupole correctors inside the solenoid, increasing the bore to accommodate the correctors, decreasing the mirror plate thickness to allow the solenoid to move closer to the cathode, cutouts in the mirror plate to allow greater optical clearance with grazing incidence cathode illumination, utilizing pancake coil mirror images to compensate the first and second integrals of the transverse fields and incorporating a bipolar power supply to allow for proper magnet standardization and quick polarity changes. This paper describes all these modifications plus the magnetic measurements and operational experience leading to the suggested modifications.

Landfill gas management facilities design guidelines

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-03-15

In British Columbia, municipal solid waste landfills generate over 1000 tonnes of methane per year; landfill gas management facilities are required to improve the environmental performance of solid waste landfills. The aim of this document, developed by the British Columbia Ministry of the Environment, is to provide guidance for the design, installation, and operation of landfill gas management facilities to address odor and pollutant emissions issues and also address health and safety issues. A review of technical experience and best practices in landfill gas management facilities was carried out, as was as a review of existing regulations related to landfill gas management all over the world. This paper provides useful information to landfill owners, operators, and other professionals for the design of landfill gas management facilities which meet the requirements of landfill gas management regulations.

Development of the electron gun control system of SSRF

International Nuclear Information System (INIS)

Zhou Dayong; Lin Guoqiang; Liu Dekang; Shen Liren

2010-01-01

An electron gun is the key part of a linac, the beam quality of which depends on beam quality of the electron gun, hence the need of a stable control system of the electron gun to ensure its safe operation.In this paper, we report our progresses in developing the linac's electron gun control system of Shanghai Synchrotron Radiation Facility (SSRF). It uses PLC as the device controllers, with the monitoring software developed on EPICS. The whole system is connected by Ethernet. The PLC and Ethernet technology ensures good reliability and easy maintenance of the electron gun control system. (authors)

BAGHEERA: A new experimental facility at CEA / Valduc for actinides studies under high dynamic loading

Science.gov (United States)

Roy, G.; Llorca, F.; Lanier, G.; Lamalle, S.; Beaulieu, J.; Antoine, P.; Martinuzzi, P.

2006-08-01

This paper is a technical presentation about a new experimental facility recently developed at CEA/Valduc, BAGHEERA, a French acronym for “Hopkinson And High Speed Experiments Glove Box”. This facility is used since mid-2003 to characterize the physical and mechanical behaviour of actinides under high dynamic loadings. For this purpose, four basic experimental devices are confined inside a single glove box: a 50 mm bore diameter single stage light gas gun, two compression and torsion split Hopkinson bars (SHPB and TSHB respectively) and a Taylor test device (TTD). Design and technical data on the experimental equipment are addressed, with a particular emphasis on the gas gun specific features due to actinide applications.

The PLX- α Plasma Guns: Progress and Plans

Science.gov (United States)

Witherspoon, F. D.; Brockington, S.; Case, A.; Cruz, E.; Luna, M.; Thio, Y. C. Francis; LANL PLX-α Team

2017-10-01

The ALPHA coaxial plasma guns are being developed to support a 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). Seven complete guns have been delivered to LANL with 6 guns currently undergoing simultaneous test firings on PLX. The guns are designed to operate over a range of parameters: 0.5-5.0 mg of Ar, Ne, N2, Kr, and Xe; 20-60 km/s; 2 × 1016 cm-3 muzzle density; and up to 7.5 kJ stored energy per gun. Each coaxial gun incorporates a fast dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured coaxial gap to suppress the blow-by instability. Optimizing parameter scans performed at HyperV have achieved : 4 mg at >50 km/s and length of 10 cm. Peak axial density 30 cm from the muzzle is 2 ×1016 cm-3. We will provide an overview of the experimental results, along with plans for further improvements in reliability, maintainability, fabricability, and plasma jet performance, with the latter focused on further improvements in the fast gas valve and the ignitors. This work supported by the ARPA-E ALPHA Program under contract DE-AR0000566 and Strong Atomics, LLC.

Development of plasma cathode electron guns

Science.gov (United States)

Oks, Efim M.; Schanin, Peter M.

1999-05-01

The status of experimental research and ongoing development of plasma cathode electron guns in recent years is reviewed, including some novel upgrades and applications to various technological fields. The attractiveness of this kind of e-gun is due to its capability of creating high current, broad or focused beams, both in pulsed and steady-state modes of operation. An important characteristic of the plasma cathode electron gun is the absence of a thermionic cathode, a feature which leads to long lifetime and reliable operation even in the presence of aggressive background gas media and at fore-vacuum gas pressure ranges such as achieved by mechanical pumps. Depending on the required beam parameters, different kinds of plasma discharge systems can be used in plasma cathode electron guns, such as vacuum arcs, constricted gaseous arcs, hollow cathode glows, and two kinds of discharges in crossed E×B fields: Penning and magnetron. At the present time, plasma cathode electron guns provide beams with transverse dimension from fractional millimeter up to about one meter, beam current from microamperes to kiloamperes, beam current density up to about 100 A/cm2, pulse duration from nanoseconds to dc, and electron energy from several keV to hundreds of keV. Applications include electron beam melting and welding, surface treatment, plasma chemistry, radiation technologies, laser pumping, microwave generation, and more.

Engineering design of the PLX- α coaxial gun

Science.gov (United States)

Cruz, E.; Brockington, S.; Case, A.; Luna, M.; Witherspoon, F. D.; Thio, Y. C. Francis; PLX-α Team

2017-10-01

We describe the engineering and technical improvements, as well as provide a detailed overview of the design choices, of the latest PLX- α coaxial gun designed for the 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion. Each coaxial gun incorporates a fast, dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. The evolution of the latest Alpha gun is presented with emphasis on its upgraded performance. Changes include a faster more robust gas valve, better-quality ceramic insulator material and enhancements to overall design layout. These changes result in a gun with increased repeatability, reduced potential failure modes, improved fault tolerance and better than expected efficiency. A custom 600- μF, 5-kV pfn and a set of six inline sparkgap switches operated in parallel are mounted directly to the back of the gun, and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. This work supported by the ARPA-E ALPHA Program under contract DE-AR0000566 and Strong Atomics, LLC.

Gun ownership and social gun culture.

Science.gov (United States)

Kalesan, Bindu; Villarreal, Marcos D; Keyes, Katherine M; Galea, Sandro

2016-06-01

We assessed gun ownership rates in 2013 across the USA and the association between exposure to a social gun culture and gun ownership. We used data from a nationally representative sample of 4000 US adults, from 50 states and District of Columbia, aged >18 years to assess gun ownership and social gun culture performed in October 2013. State-level firearm policy information was obtained from the Brady Law Center and Injury Prevention and Control Center. One-third of Americans reported owning a gun, ranging from 5.2% in Delaware to 61.7% in Alaska. Gun ownership was 2.25-times greater among those reporting social gun culture (PR=2.25, 95% CI 2.02 to 2.52) than those who did not. In conclusion, we found strong association between social gun culture and gun ownership. Gun cultures may need to be considered for public health strategies that aim to change gun ownership in the USA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Water gun vs air gun: A comparison

Science.gov (United States)

Hutchinson, D.R.; Detrick, R. S.

1984-01-01

The water gun is a relatively new marine seismic sound source that produces an acoustic signal by an implosive rather than explosive mechanism. A comparison of the source characteristics of two different-sized water guns with those of conventional air guns shows the the water gun signature is cleaner and much shorter than that of a comparable-sized air gun: about 60-100 milliseconds (ms) for an 80-in3. (1.31-liter (I)) water gun compared with several hundred ms for an 80-in3. (1.31-1) air gun. The source spectra of water guns are richer in high frequencies (>200 Hz) than are those of air guns, but they also have less energy than those of air guns at low frequencies. A comparison between water gun and air gun reflection profiles in both shallow (Long Island Sound)-and deep (western Bermuda Rise)-water settings suggests that the water gun offers a good compromise between very high resolution, limited penetration systems (e.g. 3.5-kHz profilers and sparkers) and the large volume air guns and tuned air gun arrays generally used where significant penetration is required. ?? 1984 D. Reidel Publishing Company.

Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode.

Science.gov (United States)

Poehlmann, Flavio R; Cappelli, Mark A; Rieker, Gregory B

2010-12-01

Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.

Beam emittance measurement from CERN thermionic guns

International Nuclear Information System (INIS)

Kester, O.; Rao, R.; Rinolfi, L.

1992-01-01

In the LEP Injector Linacs (LIL) a thermionic gun provides electron beams with different peak intensities at an energy of 80 keV. The beam emittances were estimated from the EGUN programme. Since the gun is of triode type, the main contribution to the emittance comes from the grid. The simulation programme does not model the real geometry by assuming a cylindrical symmetry, while the grid does not have such symmetry. A Gun Test Facility (GTF), allowing emittance measurements, based on the 3-gradients-method was installed. The experimental results are presented. (author) 6 refs.; 6 figs

The effects of pulse pressure from seismic water gun technology on Northern Pike

Science.gov (United States)

Gross, Jackson A.; Irvine, Kathryn M.; Wilmoth, Siri K.; Wagner, Tristany L.; Shields, Patrick A; Fox, Jeffrey R.

2013-01-01

We examined the efficacy of sound pressure pulses generated from a water gun for controlling invasive Northern Pike Esox lucius. Pulse pressures from two sizes of water guns were evaluated for their effects on individual fish placed at a predetermined random distance. Fish mortality from a 5,620.8-cm3 water gun (peak pressure source level = 252 dB referenced to 1 μP at 1 m) was assessed every 24 h for 168 h, and damage (intact, hematoma, or rupture) to the gas bladder, kidney, and liver was recorded. The experiment was replicated with a 1,966.4-cm3 water gun (peak pressure source level = 244 dB referenced to 1 μP at 1 m), but fish were euthanized immediately. The peak sound pressure level (SPLpeak), peak-to-peak sound pressure level (SPLp-p), and frequency spectrums were recorded, and the cumulative sound exposure level (SELcum) was subsequently calculated. The SPLpeak, SPLp-p, and SELcum were correlated, and values varied significantly by treatment group for both guns. Mortality increased and organ damage was greater with decreasing distance to the water gun. Mortality (31%) by 168 h was only observed for Northern Pike exhibiting the highest degree of organ damage. Mortality at 72 h and 168 h postexposure was associated with increasing SELcum above 195 dB. The minimum SELcum calculated for gas bladder rupture was 199 dB recorded at 9 m from the 5,620.8-cm3 water gun and 194 dB recorded at 6 m from the 1,966.4-cm3water gun. Among Northern Pike that were exposed to the large water gun, 100% of fish exposed at 3 and 6 m had ruptured gas bladders, and 86% exposed at 9 m had ruptured gas bladders. Among fish that were exposed to pulse pressures from the smaller water gun, 78% exhibited gas bladder rupture. Results from these initial controlled experiments underscore the potential of water guns as a tool for controlling Northern Pike.

Coaxial-gun design and testing for the PLX- α Project

Science.gov (United States)

Witherspoon, F. Douglas; Brockington, Samuel; Case, Andrew; Cruz, Edward; Luna, Marco; Langendorf, Samuel

2016-10-01

We describe the Alpha coaxial gun designed for a 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). The guns operate over a range of parameters: 0.5-5.0 mg of Ar, Ne, N2, Kr, and Xe; 20-60 km/s; 2 × 1016 cm-3 muzzle density; and up to 7.5 kJ stored energy per gun. Each coaxial gun incorporates a fast dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. The latest design iteration incorporates a faster more robust gas valve, an improved electrode contour, a custom 600- μF, 5-kV pfn, and six inline sparkgap switches operated in parallel. The switch and pfn are mounted directly to the back of the gun and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. We provide a brief overview of the design choices, the projected performance over the parameter ranges mentioned above, and experimental results from testing of the PLX- α coaxial gun. This work supported by the ARPA-E ALPHA Program.

Hugoniot measurements in vanadium using the LNL two-stage light-gas gun

International Nuclear Information System (INIS)

Gathers, G.R.; Mitchell, A.C.; Holmes, N.C.

1983-01-01

Hugoniot measurements on vanadium have been made using the LLNL two-stage light-gas gun. The direct collision method with electrical pins and a tantalum flyer accelerated to 6.28 km/s was used. Alt'shuler, et. al., have reported Hugoniot measurements in vanadium using explosives and the impedance match method. They reported a kink in the U/sub s/ - U/sub p/ relationship at 183 GPa, and attribute it to electronic transitions. The upper portion of their curve is based on a single point at 339 GPa. The present work was performed to further investigate the equation-of-state in the high-pressure range

A high-power millimeter wave driven steam gun for pellet injectors

International Nuclear Information System (INIS)

Itoh, Yasuyuki

1997-01-01

A concept of steam gun is proposed for using in two-stage pneumatic hydrogen isotope pellet injectors. The steam gun is driven by megawatt-level high-power millimeter waves (∼100 GHz) supplied by gyrotrons. A small amount of water is injected into its pump tube. The water is instantaneously heated by the millimeter waves and vaporized. Generated high-pressure steam accelerates a piston for compressing light gas to drive a frozen pellet. Discussions in this paper concentrate on the piston acceleration. Results show that 1 MW millimeter waves accelerate the 25 g piston to velocities of ∼200 m/s in a 1 m-long pump tube. The piston acceleration characteristics are not improved in comparison to light gas guns with first valves. The steam gun concept, however, avoids the use of a large amount of high-pressure gas for piston accelerations. In future fusion reactors, gyrotrons used during preionization and start-up phase would be available for producing required millimeter waves. (author)

Upgrading the JET pellet injector with a two-stage light gas gun prototype and future planning

International Nuclear Information System (INIS)

Kupschus, P.; Sonnenberg, K.; Bailey, W.; Gadeberg, M.; Hardaker, J.; Hedley, L.; Helm, J.; Flory, D.; McCarthy, P.; Nowak, A.; Twynam, P.; Szabo, T.; Watson, M.

1989-01-01

For about two years the Joint European TORUS (JET) has been using a multi-pellet injector jointly built by JET and the Oak Ridge National Laboratory (ORNL). This was and is jointly operated by a JET - US Pellet Team within the Pellet Agreement between JET and the US Department of Energy (US DOE) under the wider umbrella of the EURATOM - US DOE Agreement on collaborative Fusion Research. This injector is composed of the ORNL Launcher, employing three independently firing repetitive (up to 5 s -1 ) pneumatic guns for pellet speeds of up to 1.5 kms -1 , and a JET launcher-torus interface (Pellet Interface) which provides all required services to the launcher and its immediate control system. In particular, it provides the differential pumping to match the high pressures of the gun system to the vacuum pressure and flow requirements of the plasma boundary. The Pellet Interface, in its design from its conception about four years ago, was intended to be equipped with a JET built pellet launcher system employing also high-speed guns at a later date once the ORNL Launcher will have been removed as it is not compatible with the JET requirements for the Active Phase (tritium and remote handling compatibility). As a first step - to learn about the possible plasma physics benefits as well as to gain technical experience concerning the application of advanced gun technology, a JET two-stage light gas gun prototype has been developed and is now being installed in parallel with the ORNL Launcher. This paper reports on the JET pellet injector development program, its motivation and its results to date. It describes briefly the presently operated pellet injector, continues to outline the design of the prototype in more detail and finally sketches the plans for the near future. 8 refs., 11 figs., 1 tab

Thermionic gun control system for the CEBAF [Continuous Electron Beam Accelerator Facility] injector

International Nuclear Information System (INIS)

Pico, R.; Diamond, B.; Fugitt, J.; Bork, R.

1989-01-01

The injector for the CEBAF accelerator must produce a high-quality electron beam to meet the overall accelerator specifications. A Hermosa electron gun with a 2 mm-diameter cathode and a control aperture has been chosen as the electron source. This must be controlled over a wide range of operating conditions to meet the beam specifications and to provide flexibility for accelerator commissioning. The gun is controlled using Computer Automated Measurement and Control (CAMAC IEEE-583) technology. The system employs the CAMAC-based control architecture developed at CEBAF. The control system has been tested, and early operating data on the electron gun and the injector beam transport system has been obtained. This system also allows gun parameters to be stored at the operator location, without paralyzing operation. This paper describes the use of this computer system in the control of the CEBAF electron gun. 2 refs., 6 figs., 1 tab

PHERMEX electron gun development

International Nuclear Information System (INIS)

Builta, L.A.; Elliott, J.C.; Moir, D.C.; Starke, T.P.; Vecere, C.A.

1983-01-01

The PHERMEX facility is a 50-MHz standing-wave linear accelerator. Electrons are injected, accelerated, and transported to a tungsten target where bremsstrahlung x rays are generated for flash radiography of hydrodynamic systems. The purpose of this article is to describe the progress of PHERMEX electron gun development. The goal of this program is to generate and transport a 200-ns, 1-MV, 1-kA electron beam into the first PHERMEX accelerating cavity. The standard gun is operated at a pulse voltage of 550 kV, which is the limit determined by internal breakdown of the vacuum insulator. This insulator has been redesigned, and the gun has been pulsed at 750 kV without internal breakdown. At present, the current output is not limited by voltage but by a phenomenon called pulse shortening, which occurs at a pulse voltage of approximately 650 kV. The phenomenon has been investigated and the results are presented

Natural Gas Storage Facilities, US, 2010, Platts

Data.gov (United States)

U.S. Environmental Protection Agency — The Platts Natural Gas Storage Facilities geospatial data layer contains points that represent locations of facilities used for natural gas storage in the United...

Performance of the Brookhaven photocathode rf gun

International Nuclear Information System (INIS)

Batchelor, K.; Ben-Zvi, I.; Fernow, R.C.; Fischer, J.; Fisher, A.S.; Gallardo, J.; Ingold, G.; Kirk, H.G.; Leung, K.P.; Malone, R.; Pogorelsky, I.; Srinivasan-Rao, T.; Rogers, J.; Tsang, T.; Sheehan, J.; Ulc, S.; Woodle, M.; Xie, J.; Zhang, R.S.; Lin, L.Y.; McDonald, K.T.; Russell, D.P.; Hung, C.M.; Wang, X.J.

1991-01-01

The Brookhaven Accelerator Test Facility (ATF) uses a photocathode rf gun to provide a high-brightness electron beam intended for FEL and laser-acceleration experiments. The rf gun consists of 1 1/2 cells driven at 2856 MHz in π-mode with a maximum cathode field of 100 MV/m. To achieve long lifetimes, the photocathode development concentrates on robust metals such as copper, yttrium and samarium. We illuminate these cathodes with a 10-ps, frequency-quadrupled Nd:YAG laser. We describe the initial operation of the gun, including measurements of transverse and longitudinal emittance, quantum efficiencies, and peak current. The results are compared to models

Gun Control, Gun Ownership, and Suicide Prevention.

Science.gov (United States)

Lester, David

1988-01-01

Explored relationship between the extent of gun ownership and the strictness of gun control laws to suicide and homicide rates in the nine major geographic regions of the United States. Found gun ownership, rather than the strictness of gun control laws, was the strongest correlate of the rates of suicide and homicide by guns. (Author)

Whose guns are stolen? The epidemiology of Gun theft victims.

Science.gov (United States)

Hemenway, David; Azrael, Deborah; Miller, Matthew

2017-12-01

Gun theft is an important source of guns used by criminals. Yet no empirical work has focused on the characteristics of gun owners that distinguish those who have had their guns stolen from those who have not. In this study, we examine the demographics and behavioral characteristics of gun owners who report having had a gun stolen. Data come from a nationally representative probability-based online survey conducted in April 2015, with a linked follow-up survey in November 2015 that asked gun owners about any theft of their guns in the past 5 years. Of 1,604 gun-owning respondents, 2.4% (95% CI 1.6,3.6) reported that one or more guns had been stolen, with a mean number of guns stolen per theft of 1.5 (95% CI 1.0,2.0]. Risk factors for having a gun stolen were owning 6 or more guns, owning guns for protection, carrying a gun in the past month, storing guns unsafely, and living in the South region of the United States. The South accounts for 37% of US households, 43% of gun owners, and two-thirds of all gun thefts. We estimate that there are approximately 250,000 gun theft incidents per year, with about 380,000 guns stolen. We find that certain types of gun owners-who own many guns, who carry guns, and who do not store guns safely-are at higher risk to have their guns stolen. Tracing data show that states in the South are exporters of crime guns used in other states. Our survey results find that the majority of guns stolen in the US come from the South.

Plasma focusing in coaxial gun

International Nuclear Information System (INIS)

Soliman, H.M.; Masoud, M.M.; El-Khalafawy, T.

1986-01-01

A capacitor bank has been discharged between two coaxial electrodes of 6.6 cm outer diameter, 3.2 cm inner diameter and length of 31.5 cm. filled with hydrogen gas at pressure of 310 μHg. Results show that, the axial and radial plasma current reach a maximum value at a position adjacent to the gun muzzle, at which the plasma focus occurs. The measurement of the electron temperature and density and azimuthal electric field along the axis of the expansion chamber, gives a maximum value at z∼18 cm from the gun muzzle, while the axial plasma current and velocity has a minimum value at that position. These results indicate that a second point of a plasma focus has been formed at z∼18 cm from the gun muzzle, along the axis of the expansion chamber

Velocity limitations in coaxial plasma gun experiments with gas mixtures

International Nuclear Information System (INIS)

Axnaes, I.

1976-04-01

The velocity limitations found in many crossed field plasma experiments with neutral gas present are studied for binary mixtures of H 2 , He, N 2 O 2 , Ne and Ar. The apparatus used is a coaxial plasma gun with an azimuthal magnetic bias field. The discharge parameters are chosen so that the plasma is weakly ionized. In some of the mixtures it is found that one of the components tends to dominate in the sense that only a small amount (regarding volume) of that component is needed for the discharge to adopt a limiting velocity close to that for the pure component. Thus in a mixture between a heavy and a light component having nearly equal ionization potentials the heavy component dominates. Also if there is a considerable difference in ionization potential between the components, the component with the lowest ionization potential tends to dominate. (author)

Development of the Antares electron gun

International Nuclear Information System (INIS)

Stine, R.; Leland, W.; Mansfield, C.; Rosocha, L.; Jansen, J.; Gibson, R.; Allen, G.

1984-01-01

Antares is the Los Alamos National Laboratory 40-kJ, 1-ns, CO 2 laser system that is now operational. This laser system was developed for the Intertial Confinement Fusion (ICF) program and is beginning target experiments. The distributed circuit modeling, design and operation of the large electron gun developed for the final laser power amplifier are reviewed. This gun is significant because of the large electron current area, 9 m 2 ; the number of emitter blades, 48; the dual cathode current return; and the coaxial geometry and grid control. The gun components and their development are discussed. These include the emitter blades, the coaxial grid (to maintain constant electron current during the 5-μs pulse), the bonded stacked-ring insulator (to electrically insulate the grid/cathode), the Kapton/aluminum electron transmission windows (to provide an interface between gun vacuum and laser gas) and the vacuum shell (operated at a vacuum of 10 -6 torr). A unique pressure diagnostic is also discussed

A 3 GHz photoelectron gun for high beam intensity

CERN Document Server

Bossart, Rudolf; Dehler, M; Godot, J C

1996-01-01

For the Compact Linear Collider Test Facility (CTF) at CERN a new rf gun with a laser driven photocathode is under construction. The new rf gun will replace the present 11/2 cell gun and will consist of 21/2 cells accelerating the beam to a momentum of 7.0 MeV/c with an electric field strength of 100 MV/m. The strong space-charge forces at low beam energy caused by the high charge density of the electron bunches are contained by radial and longitudinal rf focusing in the gun. The rf gun under construction has been optimized by MAFIA beam simulations for an injector assembly comprising a second accelerating rf structure and an intermediate solenoid magnet correcting the beam divergence of the 21/2 cell gun. The beam loading of the rf gun, by a train of 48 bunches with 21 nC charge each, causes a strong energy decay accompanied by an increase of the flight time for the bunches with lower energy. These effects can be corrected by slightly shifting the acceleration frequency of the gun. The experimental results...

The Development of the Linac Coherent Light Source RF Gun

International Nuclear Information System (INIS)

Dowell, D

2008-01-01

The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL) requiring extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new type of light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. Therefore a new RF gun or at least the modification of an existing gun was necessary. The parameters listed in Table 1 illustrate the unique characteristics of LCLS which drive the requirements for the electron gun as given in Table 2. The gun beam quality needs to accommodate emittance growth as the beam is travels through approximately one kilometer of linac and two bunch compressors before reaching the undulator. These beam requirements were demonstrated during the recent commissioning runs of the LCLS injector and linac [2] due to the successful design, fabrication, testing and operation of the LCLS gun. The goal of this paper is to relate the technical background of how the gun was able to achieve and in some cases exceed these requirements by understanding and correcting the deficiencies of the prototype s-band RF photocathode gun, the BNL/SLAC/UCLA Gun III. This paper begins with a brief history and technical description of Gun III and the Gun Test Facility (GTF) at SLAC, and studies of the gun's RF and emittance compensation solenoid. The work at the GTF identified the gun and solenoid deficiencies, and helped to define the specifications for the LCLS gun. Section 1.1.5 describes the modeling used to compute and correct the gun RF fields and Section 1.1.6 describes the use of these fields in the electron beam simulations. The magnetic design and measurements of

Lake Wobegon’s Guns: Overestimating Our Gun-Related Competences

Directory of Open Access Journals (Sweden)

Emily Stark

2016-02-01

Full Text Available The Lake Wobegon Effect is a general tendency for people to overestimate their own abilities. In this study, the authors conducted a large, nationally-representative survey of U.S. citizens to test whether Americans overestimate their own gun-relevant personality traits, gun safety knowledge, and ability to use a gun in an emergency. The authors also tested how gun control attitudes, political identification, gender, and gun experience affect self-perceptions. Consistent with prior research on the Lake Wobegon Effect, participants overestimated their gun-related competencies. Conservatives, males, and pro-gun advocates self-enhanced somewhat more than their counterparts but this effect was primarily due to increased gun experience among these participants. These findings are important to policymakers in the area of gun use, because overconfidence in one’s gun-related abilities may lead to a reduced perceived need for gun training.

Gas separation techniques in nuclear facilities

International Nuclear Information System (INIS)

Hioki, Hideaki; Morisue, Tetsuo; Ohno, Masayoshi

1983-01-01

The literatures concerning the gas separation techniques which are applied to the waste gases generated from nuclear power plants and nuclear fuel reprocessing plants, uranium enrichment and the instrumentation of nuclear facilities are reviewed. The gas permeability and gas separation performance of membranes are discussed in terms of rare gas separation. The investigation into the change of the gas permeability and mechanical properties of membranes with exposure to radiation is reported. The theoretical investigation of the separating cells used for the separation of rare gas and the development of various separating cells are described, and the theoretical and experimental investigations concerning rare gas separation using cascades are described. The application of membrane method to nuclear facilities is explained showing the examples of uranium enrichment, the treatment of waste gases from nuclear reactor buildings and nuclear fuel reprocessing plants, the monitoring of low level β-emitters in stacks, the detection of failed fuels and the detection of water leak in fast breeder reactors. (Yoshitake, I.)

Co-axial electrodes gun characteristics

International Nuclear Information System (INIS)

Masoud, M.M.; Soliman, H.M.

1981-01-01

A coaxial electrodes gun is constructed with inner electrode diameter of 3.2 cm; outer electrode diameter of 6.6 cm and length of 25 cm it is connected to a condenser bank which delivers 4 K joule stored energy. The maximum power of the discharge is equal to 4.5x10 4 K watt; for 5 KV charging voltage. The inductance showed two main peak values of 0.257μH and 0.27μH. Theoretical calculations using one-dimension-single fluid model is μ sed, which shows that the maximum acceleration is at 0.5 sec, and the gas breakdown takes place at the gun breech; at the start of the discharge, will leave the gun after 1.625μ sec, also the drift velocity, the force and the magnetic field are given. The measured results show quite reasonable agreement with the calculations for most of the results, and the position of the plasma sheath inside the gun slightly deviated from the theoretical calculations due to viscosity and wall interaction, as well as other parameters which did not be take into consideration. The plasma current density of the sheath has its maximum value at Z=18 cm, the plasma will leave the coaxial source after 1.5μ sec, from the start of the discharge, which conferms with the theoretical model. Resistance of the gas between the electrodes, changes with time according to the particle injected from this source, and the maximum efficiency of the installation for charging voltage 5kV and pressure 80μ Hg is at approx.=10μ sec and 20.5μ sec

Acceleration of small, light projectiles (including hydrogen isotopes) to high speeds using a two-stage light gas gun

International Nuclear Information System (INIS)

Combs, S.K.; Foust, C.R.; Gouge, M.J.; Milora, S.L.

1989-01-01

Small, light projectiles have been accelerated to high speeds using a two-stage light gas gun at Oak Ridge National Laboratory. With 35-mg plastic projectiles (4 mm in diameter), speeds of up to 4.5 km/s have been recorded. The ''pipe gun'' technique for freezing hydrogen isotopes in situ in the gun barrel has been used to accelerate deuterium pellets (nominal diameter of 4 mm) to velocities of up to 2.85 km/s. The primary application of this technology is for plasma fueling of fusion devices via pellet injection of hydrogen isotopes. Conventional pellet injectors are limited to pellet speeds in the range 1-2 km/s. Higher velocities are desirable for plasma fueling applications, and the two-stage pneumatic technique offers performance in a higher velocity regime. However, experimental results indicate that the use of sabots to encase the cryogenic pellets and protect them for the high peak pressures will be required to reliably attain intact pellets at speeds of ∼3 km/s or greater. In some limited tests, lithium hydride pellets were accelerated to speeds of up to 4.2 km/s. Also, repetitive operation of the two-stage gun (four plastic pellets fired at ∼0.5 Hz) was demonstrated for the first time in preliminary tests. The equipment and operation are described, and experimental results and some comparisons with a theoretical model are presented. 17 refs., 6 figs., 2 tabs

Gun Play

Science.gov (United States)

Mechling, Jay

2008-01-01

Biology and the particular gun culture of the United States come together to explain the persistent and powerful attraction of American boys to both real guns and toy guns. The 1990s saw adults begin to conflate "the gun problem" with "the boy problem," sparking attempts (largely failed) to banish toy guns from homes and…

The Grumman/Brookhaven high-brightness, high-duty factor RF gun

International Nuclear Information System (INIS)

Lehrman, I.S.; Birnbaum, I.A.; Cole, M.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Waren, G.D.

1992-01-01

Under a joint collaboration between Brookhaven National Laboratory and the Grumman Corporation, a high-duty (>1%) photocathode RF gun is under construction for use at the ATF facility at BNL. The gun will be capable of producing short ( 300 A (after compression) and a total bunch charge in excess of 3 nC. The gun consists of 3-1/2 cells constructed from GlidCop, an alumina dispersion strengthened copper alloy. Two individually phased waveguides are used to power the first two and final two cells. (Author) 10 refs., 8 figs., 2 tabs

Compaction wave profiles: Simulations of gas gun experiments

International Nuclear Information System (INIS)

Menikoff, Ralph

2001-01-01

Mesoscale simulations of a compaction wave in a granular bed of HMX have been performed. The grains are fully resolved in order that the compaction, i.e., the porosity behind the wave front, is determined by the elastic-plastic response of the grains rather than by an empirical law for the porosity as a function of pressure. Numerical wave profiles of the pressure and velocity are compared with data from a gas gun experiment. The experiment used an initial porosity of 36%, and the wave had a pressure comparable to the yield strength of the grains. The profiles are measured at the front and back of the granular bed. The transit time for the compaction wave to propagate between the gauges determines the wave speed. The wave speed depends on the porosity behind the wave and is affected by the strength model. The yield strength needed to match the experimental wave speed is discussed. Analysis of the lead wave through the granular bed, based on impedance matches using the Hugoniot loci, indicates that the compaction wave triggers a small amount of burn, less than 1% mass fraction, on the microsecond time scale of the experiment. copyright 2001 American Institute of Physics

Low-energy plasma-cathode electron gun with a perforated emission electrode

Science.gov (United States)

Burdovitsin, Victor; Kazakov, Andrey; Medovnik, Alexander; Oks, Efim; Tyunkov, Andrey

2017-11-01

We describe research of influence of the geometric parameters of perforated electrode on emission parameters of a plasma cathode electron gun generating continuous electron beams at gas pressure 5-6 Pa. It is shown, that the emission current increases with increasing the hole diameters and decreasing the thickness of the perforated emission electrode. Plasma-cathode gun with perforated electron can provide electron extraction with an efficiency of up to 72 %. It is shown, that the current-voltage characteristic of the electron gun with a perforated emission electrode differs from that of similar guns with fine mesh grid electrode. The plasma-cathode electron gun with perforated emission electrode is used for electron beam welding and sintering.

Electrical properties of a co-axial plasma gun

International Nuclear Information System (INIS)

Allam, T.M.Y.

1997-01-01

The main interest of this work is to study the power discharge of capacitor bank through a coaxial electrodes system. Such arrangement is called the coaxial gun or coaxial accelerator. It is used in jet propulsion and in triggering of discharge in turbo engines or in plasma combustion arrangement. The main goal is to find out the efficiency of the system in both cases. coaxial plasma gun system has been constructed for this course of study. The plasma gun system consists of the plasma gun tube and the discharge chamber, the capacitor bank, the triggering system the vacuum system, the power supply, and safety and dumping system. Simple and efficient diagnostic techniques were used to measure the different parameters concerning the coaxial discharge system such as the Rogowski loop, the voltage divider, the magnetic probes, the double electric probe. Results were obtained using argon gas with an operating pressure ranging from 0.1 torr to 1 torr. The peak discharge current in the first half cycle was 44 K A with rise time of 6.25 μs for a bank charging voltage of 10 kv and gas pressure of 0.9 torr. 4-26 figs., 4-8 tabs., 33 refs

75 FR 53371 - Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas Dispersion Models

Science.gov (United States)

2010-08-31

.... PHMSA-2010-0226] Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas... safety standards for siting liquefied natural gas (LNG) facilities. Those standards require that an..., and Handling of Liquefied Natural Gas. That consensus [[Page 53372

Design of triode electron gun for electron LINAC

International Nuclear Information System (INIS)

Prasad, M.; Pande, S.A.; Hannurkar, P.R.

2003-01-01

A 10 MeV, 10 kW, electron linear accelerator is being developed at Centre for Advanced Technology, CAT for irradiation of agricultural products such as onions and potatoes. This facility required electron beam of variable energy and power. The linac structure consists of a thermionic triode gun, TW buncher and accelerator waveguide, focusing and centering coils, beam scanning system etc. The accelerator structure is disk loaded waveguide operating in TW 27π/3 mode at 2856 MHz. The triode gun is designed for operation at 50 kV. The gun is optimized for minimum grid voltage and minimum transverse beam dimensions. In this paper, the results of our optimization studies using computer code EGUN are presented. (author)

Shock wave physics group (M-6)

International Nuclear Information System (INIS)

Morris, C.E.

1981-01-01

Experimental facilities and activities of the shock wave physics group at LASL are described. The facilities include a compressed gas gun, two-stage gas gun, high explosive facilities, and a pulsed megagauss field facility

Design of single piece sabot for a single stage gas gun

Science.gov (United States)

Vemparala, Vignesh; Mathew, Arun Tom; Rao Koka, Tirumala

2017-11-01

Single piece sabot is a vital part in single stage gas guns for impact testing in aerospace industries. Depending on the type of projectile used the design of sabot varies to accommodate the testing equipment. The velocity of the projectile exiting the barrel is dependent on the material and shape of the sabot used. The material selected for the design of sabot is rigid polyurethane foam, due to their low elastic modulus and low density. Two samples of rigid PU foam is taken and tests are performed to get their exact material properties. These properties are incorporated in numerical simulation to determine the best fit for practical use. Since the PU foams has a wide range of porosity which plays a prominent role in deciding the exit velocity and accuracy of the projectile coming out of the barrel. By optimisation, to the best suitable material sample can be determined.

Gun Shows and Gun Violence: Fatally Flawed Study Yields Misleading Results

Science.gov (United States)

Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A.

2010-01-01

A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. PMID:20724672

Encyclopedia of Gun Control and Gun Rights.

Science.gov (United States)

Utter, Glenn H.

This reference volume provides information on gun control and gun rights, including resources on the debate surrounding the Second Amendment and individuals and organizations focused on gun issues, along with statutes, court cases, events, and publications surrounding this current topic. Highlighted are the important organizations and their…

Understanding the Effect of Gas Dynamics in Plasma Gun Performance for Simulating Fusion Wall Response to Disruption Events

Science.gov (United States)

Riedel, Will; Underwood, Thomas; Righetti, Fabio; Cappelli, Mark

2017-10-01

In this work, the suitability of a pulsed coaxial plasma accelerator to simulate the interaction of edge-localized modes with plasma first wall materials is investigated. Experimental measurements derived from a suite of diagnostics are presented that focus on both the properties of the plasma flow and the manner in which such jets couple with material interfaces. Specific emphasis is placed on quantifying the variation in these properties using tungsten tokens exposed to the plasma plume as the gun volume is progressively filled with more neutral gas. These results are mapped to the operational dynamics of the gun via a time-resolved Schlieren cinematic visualization of the density gradient within the flow. Resulting videos indicate the existence of two distinct modes with vastly different characteristic timescales, spatial evolution, and plasma properties. Time resolved quantification of the associated plasma heat flux for both modes, including a range spanning 150 MW m-2 - 10 GW m-2, is presented using both a fast thermocouple gauge and an IR camera. Both diagnostics in conjunction with a heat transfer model provide an accurate description of the energy transfer dynamics and operational characteristics of plasma guns. This work is supported by the U.S. Department of Energy Stewardship Science Academic Program.

High voltage processing of the SLC polarized electron gun

International Nuclear Information System (INIS)

Saez, P.; Clendenin, J.; Garden, C.; Hoyt, E.; Klaisner, L.; Prescott, C.; Schultz, D.; Tang, H.

1993-04-01

The SLC polarized electron gun operates at 120 kV with very low dark current to maintain the ultra high vacuum (UHV). This strict requirement protects the extremely sensitive photocathode from contaminants caused by high voltage (HV) activity. Thorough HV processing is thus required x-ray sensitive photographic film, a nanoammeter in series with gun power supply, a radiation meter, a sensitive residual gas analyzer and surface x-ray spectrometry were used to study areas in the gun where HV activity occurred. By reducing the electric field gradients, carefully preparing the HV surfaces and adhering to very strict clean assembly procedures, we found it possible to process the gun so as to reduce both the dark current at operating voltage and the probability of HV discharge. These HV preparation and processing techniques are described

Performance of photocathode rf gun electron accelerators

International Nuclear Information System (INIS)

Ben-Zvi, I.

1993-01-01

In Photo-Injectors (PI) electron guns, electrons are emitted from a photocathode by a short laser pulse and then accelerated by intense rf fields in a resonant cavity. The best known advantage of this technique is the high peak current with a good emittance (high brightness). This is important for short wavelength Free-Electron Lasers and linear colliders. PIs are in operation in many electron accelerator facilities and a large number of new guns are under construction. Some applications have emerged, providing, for example, very high pulse charges. PIs have been operated over a wide range of frequencies, from 144 to 3000 MHz (a 17 GHz gun is being developed). An exciting new possibility is the development of superconducting PIs. A significant body of experimental and theoretical work exists by now, indicating the criticality of the accelerator elements that follow the gun for the preservation of the PI's performance as well as possible avenues of improvements in brightness. Considerable research is being done on the laser and photocathode material of the PI, and improvement is expected in this area

Rotating-bed reactor as a power source for EM gun applications

Energy Technology Data Exchange (ETDEWEB)

Powell, J.; Botts, T.; Stickley, C.M.; Meth, S.

1980-01-01

Electromagnetic gun applications of the Rotating Bed Reactor (RBR) are examined. The RBR is a compact (approx. 1 m/sup 3/), (up to several thousand MW(th)), high-power reactor concept, capable of producing a high-temperature (up to approx. 300/sup 0/K) gas stream with a MHD generator coupled to it, the RBR can generate electric power (up to approx. 1000 MW(e)) in the pulsed or cw modes. Three EM gun applications are investigated: a rail gun thruster for orbit transfer, a rapid-fire EM gun for point defense, and a direct ground-to-space launch. The RBR appears suitable for all applications.

Rotating-bed reactor as a power source for EM gun applications

International Nuclear Information System (INIS)

Powell, J.; Botts, T.; Stickley, C.M.; Meth, S.

1980-01-01

Electromagnetic gun applications of the Rotating Bed Reactor (RBR) are examined. The RBR is a compact (approx. 1 m 3 ), (up to several thousand MW(th)), high-power reactor concept, capable of producing a high-temperature (up to approx. 300 0 K) gas stream with a MHD generator coupled to it, the RBR can generate electric power (up to approx. 1000 MW(e)) in the pulsed or cw modes. Three EM gun applications are investigated: a rail gun thruster for orbit transfer, a rapid-fire EM gun for point defense, and a direct ground-to-space launch. The RBR appears suitable for all applications

Gas storage facilities. Investigation of their social value

International Nuclear Information System (INIS)

1997-02-01

The socio-economic factors resulting from location of gas storage facilities are evaluated. Various alternatives to the existing projects are estimated, for instance 11 new pipelines, in some cases combined with new production capacity, LNG facilities, differentiated tariffs, reconstruction of decentralized heat/power plants etc. Theoretical considerations and models, among others involving gas storage abroad, are presented. Seasonal storage, emergency storage, storage controlled by economic optimization (profitable purchases, sales at highest market) are described for various types of facilities, like aquifers, caverns and LNG-stores. Natural gas supplies in Europe, infrastructure and resources are compared to the Danish conditions. Sensitivity of the Danish heating market for natural gas consumption is investigated. Reduction in energy use for space heating by 2005 will change the needs of storage of 740 Mm 3 gas to 650 Mm 3 . Extra consumption by the decentralized power/heat plants is not accounted for in this estimation. Dynamic models of the future gas consumption are based on the EU 'European Energy 2020'. (EG)

Beta II plasma-gun mechanical design and construction

International Nuclear Information System (INIS)

Pedrotti, L.; Deis, G.; Wong, R.; Calderon, M.; Chargin, A.; Garner, D.

1979-01-01

The magnetized coaxial plasma gun (located on the east end of the Beta II facility at the Lawrence Livermore Laboratory) will be used to test a new method of initiating a field reversed mirror plasma. The field-reversed mirror is expected to improve the mirror-fusion reactor by enhancing the ratio of fusion power to injected power. This paper concentrates on the mechanical design and construction of the magnetized coaxial plasma gun and also discusses the diagnostic devices necessary to demonstrate the formation of field-reversed rings

State Gun Law Environment and Youth Gun Carrying in the United States.

Science.gov (United States)

Xuan, Ziming; Hemenway, David

2015-11-01

Gun violence and injuries pose a substantial threat to children and youth in the United States. Existing evidence points to the need for interventions and policies for keeping guns out of the hands of children and youth. (1) To examine the association between state gun law environment and youth gun carrying in the United States, and (2) to determine whether adult gun ownership mediates this association. This was a repeated cross-sectional observational study design with 3 years of data on youth gun carrying from US states. The Youth Risk Behavior Survey comprises data of representative samples of students in grades 9 to 12 from biennial years of 2007, 2009, and 2011. We hypothesized that states with more restrictive gun laws have lower rates of youth gun carrying, and this association is mediated by adult gun ownership. State gun law environment as measured by state gun law score. Youth gun carrying was defined as having carried a gun on at least 1 day during the 30 days before the survey. In the fully adjusted model, a 10-point increase in the state gun law score, which represented a more restrictive gun law environment, was associated with a 9% decrease in the odds of youth gun carrying (adjusted odds ratio [AOR], 0.91 [95% CI, 0.86-0.96]). Adult gun ownership mediated the association between state gun law score and youth gun carrying (AOR, 0.94 [ 95% CI, 0.86-1.01], with 29% attenuation of the regression coefficient from -0.09 to -0.07 based on bootstrap resampling). More restrictive overall gun control policies are associated with a reduced likelihood of youth gun carrying. These findings are relevant to gun policy debates about the critical importance of strengthening overall gun law environment to prevent youth gun carrying.

Karakteristike trzanja elektromagnetskog topa / Recoil characteristics of an electromagnetic rail gun

Directory of Open Access Journals (Sweden)

Zoran B. Ristić

2009-10-01

Full Text Available U radu je razmatrano trzanje elektromagnetskog šinskog topa i upoređeno sa trzanjem konvencionalnog topa sa barutnim punjenjem. Zaključuje se da je kod elektromagnetskog topa trzanje manje nego kod topa sa barutnim punjenjem. Takođe, pokazano je da pri istim uslovima lansiranja upotreba gasne kočnice topa sa barutnim punjenjem može izmeniti karakteristike trzanja i više ih približiti ponašanju elektromagnetskog topa. / In this paper the electromagnetic rail gun recoil is discussed and compared with the recoil of a conventional, propellant gas driven gun. It is shown that, under similar launch conditions, the recoil of an electromagnetic gun is weaker than that of the powder-driven gun. The use of a muzzle brake on a powder-driven gun can alter its recoil characteristics and make its behavior closer to that of the electromagnetic rail gun.

Formation of a compact torus using a toroidal plasma gun

International Nuclear Information System (INIS)

Levine, M.A.; Pincosy, P.A.

1981-01-01

Myers, Levine and Pincosy earlier reported results using a toroidal plasma gun. The device differs from the usual coaxial plasma gun in the use of a strong toroidal bias current for enhanced efficiency, a pair of disk-like accelerating electrodes for reduced viscosity and a fast pulsed toroidal gas valve for more effective use of the injected gas sample. In addition, a technique is used for generating a toroidal current in the plasma ring. The combination offers an opportunity to deliver a plasma with a large amount of energy and to vary the density and relative toroidal and poloidal magnetic field intensities over a range of values. It is the purpose of this paper to report further experimental results, to project the gun's applications to the formation of a compact torus, and to propose a simple modification of the present apparatus as a test

Electromagnetic Guns versus Conventional Guns - a performance comparison

NARCIS (Netherlands)

Reus, N.M. de; Weijden, J. van der

1993-01-01

Performance improvement is one of the key issues of Electromagnetic gun systems compared to conventional gun systems. Due to higher muzzle velocities, the gun's fire control computer will be able to predict the target's future position more accurately because prediction time will be smaller. In this

Development of a capacitor powered rail gun for hypervelocity impact studies

International Nuclear Information System (INIS)

Shrader, J.E.

1983-01-01

Boeing has built and tested several rail gun designs using two different capacitor banks as power sources. For each design, the muzzle velocity predicted with the Boeing Electromagnetic Gun code (BEMG) matched the measured muzzle velocity within 5%, providing gas sealing between the rails and the dielectric of the barrel was maintained. This did not validate the model, but gave reasonable confidence in it. Using the BEMG model, a parametric study was conducted to determine the sensitivity of muzzle velocities between 2 and 5 km/s to the input variables. A practical point design was assumed, and then each parameter individually varied while the others were held constant. The point design assumed an initial velocity of 0.5 km/s and an inductance per unit length (L') of 0.8 x 10 -6 H/m. Other parameters were similar to the earlier designs. The earlier designs tested had no initial velocity, and an L' of 0.3 x 10 6 H/m. A gas gun was assumed to produce the initial velocity, and resulted in only modest increases in muzzle velocity. However, it eliminated a separate make switch, since a foil across the back of the projectile becomes a make switch, and it is expected to substantially reduce rail erosion near the breech of the gun. Rail erosion was a significant problem for repeated firings in earlier designs. The parametric study showed that for the velocities of interest, increasing L' was the single best way to improve gun performance. In a practical gun, this will be achieved by making a two turn barrel, rather than a single turn barrel. The results of this study will be used to design, build and test a small gun (about 9 mm bore) using a 150 kJ capacitor bank as a power source. Using the experience gained with this gun, a large gun (about 20 mm bore) will be designed, built and tested using a 1.3 MJ capacitor bank

Atmospheric pressure DBD gun and its application in ink printability

International Nuclear Information System (INIS)

Chen Qiang; Zhang Yuefei; Han Erli; Ge Yuanjing

2005-01-01

In this paper, a plasma source discharging at atmospheric pressure and its characterization diagnosed by a Langmuir probe and a digital camera are presented. As an application the dielectric barrier discharge (DBD) gun modifying an ultraviolet cured resin surface for ink printability is reported. The results from the digital camera indicate the uniformity and homogeneity of the plasma generated from the gun in the downstream but depending on the input power, diameter of electrodes, gas flow rates and the distance between the substrates and the nozzle. The contact angle measurement proves the efficiency of gun during the surface modification. The ink printability following DBD gun processing described here was significantly improved. The performed surface analysis using Fourier transform infrared indicates that the polarity of surface grafted in plasma is responsible for the film printability

Long pulse, plasma cathode E-gun

International Nuclear Information System (INIS)

Goebel, D.M.; Schumacher, R.W.; Watkins, R.M.

1993-01-01

A unique, long-pulse E-gun has been developed for high-power tube applications. The Hollow-Cathode-Plasma (HCP) E-gun overcomes the limitations of conventional thermionic-cathode guns that have limited current density (typically ≤ 10 A/cm 2 ) or field-emission guns that offer high current density but suffer from short pulsewidth capability (typically 50 A/cm 2 ), long-pulse operation without gap closure, and also requires no cathode-heater power. The gun employs a low-pressure glow discharge inside a hollow cathode (HC) structure to provide a stable, uniform plasma surface from which a high current-density electron beam can be extracted. The plasma density is controlled by a low-voltage HC discharge pulser to produce the desired electron current density at the first grid of a multi-grid accelerator system. A dc high-voltage electron-beam supply accelerates the electrons across the gap, while the HC pulser modulates the beam current to generate arbitrary pulse waveforms. The electron accelerator utilizes a multi-aperture array that produces a large area, high perveance (>35 μpervs) beam consisting initially of many individual beamlets. The E-beam is normally operated without an applied magnetic field in the ion-focused regime, where the plasma produced by beam ionization of a background gas space-charge neutralizes the beam, and the Bennett self-pinch compresses the beamlets and increases the current density. The self-pinched beam has been observed to propagate over a meter without beam breakup or instabilities. The HCP E-gun has been operated at voltages up to 150 kV, currents up to 750 A, and pulse lengths of up to 120 μsec

Not an 'iron pipeline', but many capillaries: regulating passive transactions in Los Angeles' secondary, illegal gun market.

Science.gov (United States)

Chesnut, Kelsie Y; Barragan, Melissa; Gravel, Jason; Pifer, Natalie A; Reiter, Keramet; Sherman, Nicole; Tita, George E

2017-08-01

California has strict firearm-related laws and is exceptional in its regulation of firearms retailers. Though evidence suggests that these laws can reduce illegal access to guns, high levels of gun violence persist in Los Angeles (LA), California. This research seeks to describe the sources of guns accessed by active offenders in LA, California and reports offenders' motivations for obtaining guns. Los Angeles County Jail (LACJ) system (four facilities). Random sampling from a screened pool of eligible participants was used to conduct qualitative semistructured interviews with 140 incarcerated gun offenders in one of four (LACJ) facilities. Researchers collected data on firearm acquisition, experiences related to gun violence, and other topics, using a validated survey instrument. Grounded theory guided the collection and analysis of data. Respondents reported possession of 77 specific guns (79.2% handguns) collectively. Social networks facilitate access to illegal guns; the majority of interviewees acquired their illegal guns through a social connection (85.7%) versus an outside broker/unregulated retailer (8.5%). Most guns were obtained through illegal purchase (n=51) or gift (n=15). A quarter of gun purchasers report engaging in a passive transaction, or one initiated by another party. Passive gun buyers were motivated by concerns for personal safety and/or economic opportunity. In LA's illegal gun market, where existing social relationships facilitate access to guns across a diffuse network, individuals, influenced by both fear and economic opportunity, have frequent opportunities to illegally possess firearms through passive transactions. Gun policies should better target and minimise these transactions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Modelling and design of high compression electron guns for EBIS/T charge breeders

CERN Document Server

AUTHOR|(CDS)2087190; Zschornack, G.; Lettry, J.; Wenander, F.

In this thesis the optimization of the REXEBIS charge breeder at the ISOLDE facility is presented. REXEBIS in its current state provides a current density of 200A/cm² inside the trapping region at 2 T and will be optimized to the physical limit of its design. To overcome this limit a new electron gun, the HEC² gun, was designed in collaboration with the BNL and is in commission at TestEBIS. This electron gun promises a current density of >10 kA/cm², which decreases the charge breeding time significantly. This thesis presents novel simulation techniques supporting the commissioning phase by explaining the sources of occurring loss current and, in addition, evaluate the currently installed collector for compatibility with the HEC2 gun operating at its design limit. The experience gained from the commission of the HEC² gun and the established numerical techniques lead to the development of a smaller high-compression electron gun for medical purposes, the MEDeGUN. This electron gun should provide a high-quali...

The Effects of Gun Ownership Rates and Gun Control Laws on Suicide Rates

OpenAIRE

Mark Gius

2011-01-01

The purpose of the present study is to determine the effects of gun control laws and gun ownership rates on state-level suicide rates. Using the most recent data on suicide rates, gun control measures, and gun ownership rates, the results of the present study suggest that states that require handgun permits have lower gun-related suicide rates, and states that have higher gun ownership rates have higher gun-related suicide rates. Regarding non-gun suicides, results suggest that stricter gun c...

Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

Energy Technology Data Exchange (ETDEWEB)

S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

2008-04-01

A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: • Identifies pre-conceptual design requirements • Develops test loop equipment schematics and layout • Identifies space allocations for each of the facility functions, as required • Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems • Identifies pre-conceptual utility and support system needs • Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs.

Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

International Nuclear Information System (INIS)

S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

2008-01-01

A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: (1) Identifies pre-conceptual design requirements; (2) Develops test loop equipment schematics and layout; (3) Identifies space allocations for each of the facility functions, as required; (4) Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems; (5) Identifies pre-conceptual utility and support system needs; and (6) Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs

Lasers for RF guns: Proceedings

International Nuclear Information System (INIS)

Srinivasan-Rao, T.

1994-01-01

In the past decade, laser driven RF guns have matured from a device under development to a proven source for high brightness and low emittance electron beams. The reliability of the electron beam from these sources is dictated by the laser system that drives it. In addition, capabilities of the laser systems play a vital role in the design of the electron source for future machines such as the TESLA and NLC. The purpose of this workshop was to provide a forum for discussing the design criteria for the laser systems so that the reliability of the existing sources could be improved and the future machines could be serviced. The Workshop brought together experts in RF Guns, accelerators, and lasers, from both the commercial and academic community. Most of the presentations, discussions and conclusions at the workshop are included in these proceedings. The contents are divided into three sections, Section I contains the invited talks that outline the requirements of the RF Guns and the capabilities of the laser systems to meet these requirements. Section II includes most of the papers presented in the poster session. These papers describe various laser systems used with electron guns, schemes to modify the laser beam profile to optimize the electron bunch, and computer simulations of electron trajectories. Section III contains the summaries of the working groups. As the summary section indicates, with sufficient feed back systems, the electron gun could be made to operate reliably with minimum downtime, using commercial lasers currently available. The design of laser systems for future colliders depend critically on the choice of the cathode m the gun and its efficiency. Tentative designs of laser systems for the TESLA test facility and LCLS had been drawn assuming a copper cathode. Using a more efficient cathode will ease the energy requirement of the laser and simplify the design. The individual papers have been cataloged separately elsewhere

Gun Safety

Science.gov (United States)

Many U.S. households have guns, but they can cause harm if not handled properly. Here are some things you can do to keep yourself and ... safe: Teach children that they shouldn't touch guns and that if they see a gun, to ...

Beam-Based Procedures for RF Guns

CERN Document Server

Krasilnikov, Mikhail; Grabosch, H J; Hartrott, Michael; Hui Han, Jang; Miltchev, Velizar; Oppelt, Anne; Petrosyan, Bagrat; Staykov, Lazar; Stephan, Frank

2005-01-01

A wide range of rf photo injector parameters has to be optimized in order to achieve an electron source performance as required for linac based high gain FELs. Some of the machine parameters can not be precisely controlled by direct measurements, whereas the tolerance on them is extremely tight. Therefore, this should be met with beam-based techniques. Procedures for beam-based alignment (BBA) of the laser on the photo cathode as well as solenoid alignment have been developed. They were applied at the Photo Injector Test facility at DESY Zeuthen (PITZ) and at the photo injector of the VUV-FEL at DESY Hamburg. A field balance of the accelerating mode in the 1 ½ cell gun cavity is one of the key beam dynamics issues of the rf gun. Since no direct field measurement in the half and full cell of the cavity is available for the PITZ gun, a beam-based technique to determine the field balance has been proposed. A beam-based rf phase monitoring procedure has been developed as well.

Magnetized gun experiments

International Nuclear Information System (INIS)

Jarboe, T.R.; Henins, I.; Hoida, H.W.; Marshall, J.; Sherwood, A.R.

1981-01-01

In the Los Alamos Magnetized Gun Experiment we are attempting to produce a compact torus in a manner similar to an earlier experiment of Alfven. In our experiment a solenoidal coil is placed inside the inner electrode of a coaxial plasma gun. This coil produces an axial magnetic field inside the inner electrode which diverges and becomes a largely radial field in front of the gun muzzle. The idea is that when the gun is fired, the plasma escaping from the gun stretches these radial fields along the axial direction away from the gun, and these field lines can reconnect behind the plasma forming the poloidal field of the compact torus. The magnetic field generated by the gun current becomes the toroidal field and the major axis of the compact torus will be the same as the axis of the coaxial gun. Recent interest in this possible method of compact torus generation was stimulated by C. Hartman, and the approach is also being pursued in the field-reversed plasma gun experiment at LLL

Development of laser heated high current DC electron gun

International Nuclear Information System (INIS)

Banerjee, Srutarshi; Bhattacharjee, Dhruva; Kandaswamy, E.; Ghodke, S.R.; Tiwari, Rajnish; Bakhtsingh, R.I.

2015-01-01

The paper deals with the development of a Laser heated cathode for Electron Accelerator. The electron gun is meant for Megawatt-class DC Accelerator for Electron Beam Flue Gas Treatment applications. Conventionally, LaB 6 cathode is indirectly heated by tungsten filaments whereas in the newly proposed gun, Laser is utilized for heating. A Nd:YAG Laser is used to heat the LaB 6 cathode to emission temperatures. The characterization of cathode heating at various Laser powers has been carried out. In initial trials, it has been observed that with 125 W of Laser power, the LaB 6 pellet was heated to 1315 ° C. Based on these experimental results, an electron gun rated for 30 kV, 350 mA CW has been designed. The optimization of gun electrode geometry has been done using CST Particle Studio in order to tune the various electron gun parameters. The beam diameter obtained in simulation is 8 mm at 100 mm from the LaB 6 cathode. The perveance obtained is 7.1 x 10 -8 A/V 3/2 . The Laser heated cathode has the advantages of eliminating the magnetic field effects of filament on the electron beam, electrical isolation needed for gun filament power supplies and better electron beam emittances. (author)

Gas storage facilities. Investigation of their social value. Supplement

International Nuclear Information System (INIS)

1997-02-01

The socio-economic factors resulting from location of gas storage facilities are evaluated. Various alternatives to the existing projects are estimated, for instance 11 new pipelines, in some cases combined with new production capacity, LNG facilities, differentiated tariffs, reconstruction of decentralized heat/power plants etc. Theoretical considerations and models, among others involving gas storage abroad, are presented. Seasonal storage, emergency storage, storage controlled by economic optimization (profitable purchases, sales at highest market) are described for various types of facilities, like aquifers, caverns and LNG-stores. Natural gas supplies in Europe, infrastructure and resources are compared to the Danish conditions. Sensitivity of the Danish heating market for natural gas consumption is investigated. Reduction in energy use for space heating by 2005 will change the needs of storage of 740 Mm 3 gas to 650 Mm 3 . Extra consumption by the decentralized power/heat plants is not accounted for in this estimation. Dynamic models of the future gas consumption are based on the EU 'European Energy 2020'. (EG)

Improving the Performance of Two-Stage Gas Guns By Adding a Diaphragm in the Pump Tube

Science.gov (United States)

Bogdanoff, D. W.; Miller, Robert J.

1995-01-01

Herein, we study the technique of improving the gun performance by installing a diaphragm in the pump tube of the gun. A CFD study is carried out for the 0.28 in. gun in the Hypervelocity Free Flight Radiation (HFF RAD) range at the NASA Ames Research Center. The normal, full-length pump tube is studied as well as two pump tubes of reduced length (approximately 75% and approximately 33% of the normal length). Significant improvements in performance are calculated to be gained for the reduced length pump tubes upon the addition of the diaphragm. These improvements are identified as reductions in maximum pressures in the pump tube and at the projectile base of approximately 20%, while maintaining the projectile muzzle velocity or as increases in muzzle velocity of approximately 0.5 km/sec while not increasing the maximum pressures in the gun. Also, it is found that both guns with reduced pump tube length (with diaphragms) could maintain the performance of gun with the full length pump tube without diaphragms, whereas the guns with reduced pump tube lengths without diaphragms could not. A five-shot experimental investigation of the pump tube diaphragm technique is carried out for the gun with a pump tube length of 75% normal. The CFD predictions of increased muzzle velocity are borne out by the experimental data. Modest, but useful muzzle velocity increases (2.5 - 6%) are obtained upon the installation of a diaphragm, compared to a benchmark shot without a diaphragm.

Coaxial gun parameters and X-ray emission

International Nuclear Information System (INIS)

Soliman, H.M.; El-Aragi, G.M.; Saudy, A.H.; Masoud, M.M.

1994-01-01

The paper presents the results of investigation with 3 kJ coaxial plasma gun, which operated with argon gas at pressure 0.8 torr. The coaxial plasma gun parameters are investigated by pick up coils, double electric probe, and x-ray probe. The mean electron temperature and density of the ejected plasma are 25 eV and 10 15 cm -3 respectively. The maximum kinetic pressure of the ejected plasma in the expansion chamber appears after 10 μs from the start of the discharge current. The energetic electrons is detected by an x-ray probe which showed a single pulse of electrons with energy ≅ 3 Kev. (orig.)

Gas processing at DOE nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Jacox, J.

1995-02-01

The term {open_quotes}Gas Processing{close_quotes} has many possible meanings and understandings. In this paper, and panel, we will be using it to generally mean the treatment of gas by methods other than those common to HVAC and Nuclear Air Treatment. This is only a working guideline not a rigorous definition. Whether a rigorous definition is desirable, or even possible is a question for some other forum. Here we will be discussing the practical aspects of what {open_quotes}Gas Processing{close_quotes} includes and how existing Codes, Standards and industry experience can, and should, apply to DOE and NRC Licensed facilities. A major impediment to use of the best engineering and technology in many nuclear facilities is the administrative mandate that only systems and equipment that meet specified {open_quotes}nuclear{close_quotes} documents are permissible. This paper will highlight some of the limitations created by this approach.

Gun Safety (For Kids)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Gun Safety KidsHealth / For Kids / Gun Safety What's in ... from guns outside the home. If You Have Guns in Your Home If your parents keep guns ...

State Gun Policy and Cross-State Externalities: Evidence from Crime Gun Tracing

OpenAIRE

Brian Knight

2013-01-01

This paper provides a theoretical and empirical analysis of cross-state externalities associated with gun regulations in the context of the gun trafficking market. Using gun tracing data, which identify the source state for crime guns recovered in destination states, we find that firearms in this market tend to flow from states with weak gun laws to states with strict gun laws, satisfying a necessary condition for the existence of cross-state externalities in the theoretical model. We also fi...

Design of a high-brightness, high-duty factor photocathode electron gun

International Nuclear Information System (INIS)

Lehrman, I.S.; Birnbaum, I.A.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Ben-Zvi, I.; Batchelor, K.; Gallardo, J.C.; Kirk, H.G.; Srinivasan-Rao, T.; Warren, G.D.

1991-09-01

The proposed UV-FEL user's facility at Brookhaven National Laboratory will require a photocathode gun capable of producing short (< 6 psec) bunches of electrons in high repetition rates (5 kHz), low energy spread (< 1.5.%), a peak current of 300 A (after compression) and a total bunch charge of up to 2 nC. At the highest charge the normalized transverse emittance should be less than 7 π mm-mrad. We are presently designing a gun that is expected to exceed these requirements. This gun will consist of 3 1/2 cells, constructed of GlidCop-15, an aluminum oxide dispersion strengthened copper alloy. The gun will be capable of operating at duty factors in excess of 1%. Extensive beam dynamics studies of the gun were used to determine the effect of varying the length of the first cell, shaping the apertures between cells, and increasing the number of cells. In addition, a detailed thermal and mechanical study of the gun was performed to ensure that the thermal stresses were well within the allowable limits and that copper erosion of the water channels would not occur

Blower Gun pellet injection system for W7-X

Energy Technology Data Exchange (ETDEWEB)

Dibon, M., E-mail: mathias.dibon@ipp.mpg.de [Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Baldzuhn, J.; Beck, M. [Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Cardella, A. [Lehrstuhl für Nukleartechnik, TU Munich, Boltzmannstr. 15, 85748 Garching (Germany); Köchl, F. [Atominstitut, TU Wien, 1020 Vienna (Austria); Kocsis, G. [Wigner RCP, RMI, P.O. Box 49, H-1525 Budapest-114 (Hungary); Lang, P.T. [Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Macian-Juan, R. [Lehrstuhl für Nukleartechnik, TU Munich, Boltzmannstr. 15, 85748 Garching (Germany); Ploeckl, B. [Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Szepesi, T. [Wigner RCP, RMI, P.O. Box 49, H-1525 Budapest-114 (Hungary); Weisbart, W. [Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany)

2015-10-15

Highlights: • Operational principle of the ASDEX Upgrade Blower Gun. • Guiding tube properties for pellet guiding according to the requirements of W7-X. • Diagnostics for the characterization of the injection system. • Experimental procedure to investigate the performance of the Blower Gun. • Results concerning pellet speeds, mass loss, delivery efficiency and exit angle. - Abstract: Foreseen to perform pellet investigations in the new stellarator W7-X, the former ASDEX Upgrade Blower Gun was revised and revitalized. The systems operational characteristics have been surveyed in a test bed. The gun is designed to launch cylindrical pellets with 2 mm diameter and 2 mm length, produced from frozen deuterium D{sub 2}, hydrogen H{sub 2} or a gas mixture consisting of 50% H{sub 2} and 50% D{sub 2}. Pellets are accelerated by a short pulse of pressurized helium propellant gas to velocities in the range of 100–250 m/s. Delivery reliabilities at the launcher exit reach almost unity. The initial pellet mass is reduced to about 50% during the acceleration process. Pellet transfer to the plasma vessel was investigated by a first mock up guiding tube version. Transfer through this S-shaped stainless steel guiding tube (inner diameter 8 mm; length 6 m) containing two 1 m curvature radii was investigated for all pellet types. Tests were performed applying repetition rates from 2 Hz to 50 Hz and propellant gas pressures ranging from 0.1 to 0.6 MPa. For both H{sub 2} and D{sub 2}, low overall delivery efficiencies were observed at slow repetition rates, but stable efficiencies of about 90% above 10 Hz. About 10% of the mass is eroded while flying through the guiding tube. Pellets exit the guiding tube with an angular spread of less than 14°.

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)

Development of intense pulsed heavy ion beam diode using gas puff plasma gun as ion source

International Nuclear Information System (INIS)

Ito, H.; Higashiyama, M.; Takata, S.; Kitamura, I.; Masugata, K.

2006-01-01

A magnetically insulated ion diode with an active ion source of a gas puff plasma gun has been developed in order to generate a high-intensity pulsed heavy ion beam for the implantation process of semiconductors and the surface modification of materials. The nitrogen plasma produced by the plasma gun is injected into the acceleration gap of the diode with the external magnetic field system. The ion diode is operated at diode voltage approx. =200 kV, diode current approx. =2 kA and pulse duration approx. =150 ns. A new acceleration gap configuration for focusing ion beam has been designed in order to enhance the ion current density. The experimental results show that the ion current density is enhanced by a factor of 2 and the ion beam has the ion current density of 27 A/cm 2 . In addition, the coaxial type Marx generator with voltage 200 kV and current 15 kA has been developed and installed in the focus type ion diode. The ion beam of ion current density approx. =54 A/cm 2 is obtained. To produce metallic ion beams, an ion source by aluminum wire discharge has been developed and the aluminum plasma of ion current density ∼70 A/cm 2 is measured. (author)

Radon gas in oil and natural gas production facilities

International Nuclear Information System (INIS)

Chandler, W.P.

1994-01-01

Radon gas is a naturally occurring radionuclide that can be found in some oil and natural gas production facilities, either as a contaminant in a natural gas stream or derived from Radium dissolved in formation waters. The gas itself is not normally a health hazard, but it's decay products, which can be concentrated by plate-out or deposition as a scale in process equipment, can be a health hazard for maintenance personnel. To evaluate possible health hazards, it is necessary to monitor for naturally occurring radioactive materials (NORM) in the gas stream and in the formation water. If Radon and/or Radium is found, a monitoring programme should be initiated to comply with National or State requirements. In some instances, it has been found necessary to dispose of silt and scale materials as low level radioactive waste. 8 refs

Measurements of Transverse Emittance for RF Photocathode Gun at the PAL

CERN Document Server

Park Jang Ho; Park, Sung-Ju; Soo Ko In; Wang, Xijie; Woon Parc, Yong; Xiang, Dao

2005-01-01

A BNL GUN-IV type RF photo-cathode gun is under fabrication for use in the FIR (Far Infra-Red) facility being built at the Pohang Accelerator Laboratory (PAL). Performance test of the gun will include the measurement of transverse emittance profile along the longitudinal direction. Successful measurement of the emittance profile will provide powerful tool for the commissioning of the 4GLS (4th generation light source) injectors based on the emittance compensation principle. We are going to achieve this withthe use of pepper-pot based emittance meters that can be moved along the longitudinal direction. In this article, we present design considerations on the emittance meter with the resolution of 1 mm mrad.

Solid deuterium pellet injection with a two-stage pneumatic gun

International Nuclear Information System (INIS)

Reggiori, A.; Riva, G.; Daminelli, G.; Frattolillo, A.; Martinis, L.; Scaramuzzi, F.

1989-01-01

Recent results on injection of D 2 pellets, using an improved light gas gun, are reported. In order to overcome the limits imposed by the low mechanical strength of solid hydrogen, a double-piston gun has been developed, in which the pressure pulse can be shaped in different ways, allowing reduction of the maximum acceleration of the pellet. Experiments have been performed with plastic and D 2 pellets. Velocities above 2500 m/s have been obtained with unbroken D 2 pellets

High-quality electron pulse generation from a laser photocathode RF gun

International Nuclear Information System (INIS)

Yang, Jinfeng; Sakai, Fumio; Aoki, Yasushi

1999-01-01

A laser photocathode RF gun system was developed for ultra short X-ray pulse generation via the inverse Compton scattering. The gun is a BNL-type S-band RF gun and the performance test of the gun was performed at the Linear Accelerator Facility in the Institute of Scientific and Industries Research, Osaka University. The gun system produced 115 pC electron bunches with the energy of 1.6 MeV under the condition of RF peak power of 1.5 MW and laser pulse energy of 65 μJ. The quantum efficiency and dark current were obtained to be 10 -5 and 0.6 nA at the repetition rate of 10 Hz, respectively. The energy and charge of the electron bunch were measured as a function of laser injection phase. Furthermore, the electron bunches were accelerated up to 117 MeV by three s-band TW linacs and the energy monochromaticity (ΔE/E) of the beam was 1.2%. The transverse emittance was also experimentally investigated at the end of the linacs. (author)

Results from AFWL 230 kJ coaxial plasma gun experiments

International Nuclear Information System (INIS)

Hall, D.J.; Baker, W.L.; Beason, J.D.; Clouse, C.J.; Degnan, J.H.; Dietz, D.; Hackett, K.E.; Higgins, P.L.; Holmes, J.L.; Price, D.W.

1988-01-01

A coaxial plasma gun has been operated on the AFWL 0.5 MJ capacitor bank. A Marshall valve actuated by an explosive detonator is used to puff hydrogen gas from a small high pressure plenum into the breech of the gun. After a set delay from the explosion the capacitor bank is discharged across the electrodes of the coaxial gun. The operating mode of the gun can be changed by varying the plenum pressure and the firing delay. Over 150 shots have been fired, varying delay, plenum pressure, and initial stored energy. Initial plenum pressures were varied from 250 to 750 psi, and firing delays ranged from 0.8 msec to 2.2 msec. Experiments were conducted at 90, 176, and 230 kJ of initial stored energy (50, 70, adn 80 kV charge). Rogowski coils were used to measure current and magnetic field within the plasma at 25 axial locations along the gun. The coils were installed in grooves on the inner surface of the outer conductor. Signals from the coils were passively integrated. Integrator time constants ranged from 95 to 114 μsec. Time histories of magnetic field profiles are presented. These are used to describe the operating mode of the gun

Stability and performance studies of the PITZ photoelectron gun

Energy Technology Data Exchange (ETDEWEB)

Isaev, Igor

2018-02-15

The invention of free electron lasers (FELs) opened new opportunities for the investigation of natural phenomena. However, the operation of a FEL requires high energy, high peak current electron beams with very small transverse emittance which causes extreme requirements for the corresponding electron sources. Besides the high beam quality, the electron sources must have very high operational stability and reliability. One of the electron source types which satisfy FEL requirements is a photoelectron gun. Photoelectron guns combine photoemissive electron generation and direct acceleration in a Radio Frequency (RF) cavity. The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was established as a test stand of the electron source for FELs like FLASH and the European XFEL in Hamburg. The studies of the beam emittance at PITZ showed that the gun is able to produce electron beams with emittance even smaller than it is required by XFEL specifications. But the experiments on the emittance revealed discrepancies between expected gun behavior and observation, such as the difference in optimal parameters for the smallest emittance value, asymmetry of the transverse beam profile and the phase spaces. The work performed at PITZ includes preparation of several RF guns for their subsequent operation at FLASH and the European XFEL. RF conditioning of a gun cavity is one of the major steps of the preparation of a high brightness electron source required for modern FELs. A thorough procedure is applied to increase the peak and average RF power in the gun cavity, including an increase of the repetition rate and RF pulse length combined with a gun solenoid current sweep. The main goals of this thesis are: (1) an attempt of deep understanding of physical processes taking place during operation of a photoelectron gun (conditioning process, parameters adjustments); (2) definition of operational problems sources and explanation of the experimentally obtained results in the gun

Stability and performance studies of the PITZ photoelectron gun

International Nuclear Information System (INIS)

Isaev, Igor

2018-02-01

The invention of free electron lasers (FELs) opened new opportunities for the investigation of natural phenomena. However, the operation of a FEL requires high energy, high peak current electron beams with very small transverse emittance which causes extreme requirements for the corresponding electron sources. Besides the high beam quality, the electron sources must have very high operational stability and reliability. One of the electron source types which satisfy FEL requirements is a photoelectron gun. Photoelectron guns combine photoemissive electron generation and direct acceleration in a Radio Frequency (RF) cavity. The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was established as a test stand of the electron source for FELs like FLASH and the European XFEL in Hamburg. The studies of the beam emittance at PITZ showed that the gun is able to produce electron beams with emittance even smaller than it is required by XFEL specifications. But the experiments on the emittance revealed discrepancies between expected gun behavior and observation, such as the difference in optimal parameters for the smallest emittance value, asymmetry of the transverse beam profile and the phase spaces. The work performed at PITZ includes preparation of several RF guns for their subsequent operation at FLASH and the European XFEL. RF conditioning of a gun cavity is one of the major steps of the preparation of a high brightness electron source required for modern FELs. A thorough procedure is applied to increase the peak and average RF power in the gun cavity, including an increase of the repetition rate and RF pulse length combined with a gun solenoid current sweep. The main goals of this thesis are: (1) an attempt of deep understanding of physical processes taking place during operation of a photoelectron gun (conditioning process, parameters adjustments); (2) definition of operational problems sources and explanation of the experimentally obtained results in the gun

Design of e-gun for large KrF amplifiers

International Nuclear Information System (INIS)

Reilly, D.A.; Von Rosenberg, C.W.

1985-01-01

The design of very large single-aperture laser amplifier for an angular multiplexed laser fusion system requires advances in excimer laser e-gun technology beyond existing designs. Scaling considerations dictate the use of multiple e-guns to pump a single laser; in the present case the authors will discuss the scaling and design features of one of the ten e-guns being developed to pump the Los Alamos Polaris Power Amplifier Module. Multiple e-guns minimize the diode self-magnetic field, lowering the size of the imposed guide magnetic field, and reducing the diode impendance collapse. Multiple guns also result in lowered current rise times, reduce the development cost of the technology at the prototype stage, and, of course, limit the cost due to operation failures in the e-gun. The present design utilizes the expanding electron flow diode to provide uniform electron flow into the gas from a high-current density cold cathode (approx. =50 A/cm 2 ). Laminated iron and an imposed dipole field are utilized for B-field shaping. The applied B field lines trace from the anode, terminate on the cathode, and are then conducted through the shank to beyond the bushing. This feature not only provides for fully expanded electron flow from cathode to anode, but it also allows for self-magnetic field insulation of the shank and bushing, thus minimizing voltage standoff distances, inductance, and rise time. A single large aspect ratio racetrack-shaped bushing on each e-gun is provided with robust grading to limit field concentration at the ends

Improved DC Gun and Insulator Assembly

Energy Technology Data Exchange (ETDEWEB)

Neubauer, Michael [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2015-01-11

Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

Design and experiment of high-current low-pressure plasma-cathode e-gun

International Nuclear Information System (INIS)

Xie Wenkai; Li Xiaoyun; Wang Bin; Meng Lin; Yan Yang; Gao Xinyan

2006-01-01

The preliminary design of a new high-power low pressure plasma-cathode e-gun is presented. Based on the hollow cathode effect and low-pressure glow discharge empirical formulas, the hollow cathode, the accelerating gap, and the working gas pressure region are given. The general experimental device of the low-pressure plasma cathode electron-gun generating high current density e-beam source is shown. Experiments has been done in continuous filled-in gases and gases-puff condition, and the discharging current of 150-200 A, the width of 60 μs and the collector current of 30-80 A, the width of 60 μs are obtained. The results show that the new plasma cathode e-gun can take the place of material cathode e-gun, especially in plasma filled microwave tubes. (authors)

Temporal association between federal gun laws and the diversion of guns to criminals in Milwaukee.

Science.gov (United States)

Webster, Daniel W; Vernick, Jon S; Bulzacchelli, Maria T; Vittes, Katherine A

2012-02-01

The practices of licensed gun dealers can threaten the safety of urban residents by facilitating the diversion of guns to criminals. In 2003, changes to federal law shielded gun dealers from the release of gun trace data and provided other protections to gun dealers. The 14-month period during which the dealer did not sell junk guns was associated with a 68% reduction in the diversion of guns to criminals within a year of sale by the dealer and a 43% increase in guns diverted to criminals following sales by other dealers. The laws were associated with a 203% increase in the number of guns diverted to criminals within a year of sale by the gun store, which was the focus of this study. Policies which affect gun dealer accountability appeared to influence the diversion of guns to criminals.

RF study and 3-D simulations of a side-coupling thermionic RF-gun

International Nuclear Information System (INIS)

Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

2014-01-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012 © . RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance

RF study and 3-D simulations of a side-coupling thermionic RF-gun

Science.gov (United States)

Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

2014-02-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

Effects of Exposure to Gun Violence in Movies on Children's Interest in Real Guns.

Science.gov (United States)

Dillon, Kelly P; Bushman, Brad J

2017-11-01

More US children die by accidental gun use than children in other developed countries. One factor that can influence children's interest in guns is exposure to media containing guns. To test whether children who see a movie containing guns will handle a real gun longer and will pull the trigger more times than children who see the same movie not containing guns. One hundred four children aged 8 to 12 years recruited through advertisements were randomly assigned in pairs to watch a 20-minute PG-rated movie containing or not containing guns in a university laboratory. Children then played with toys and games in a room for 20 minutes while being video recorded. A cabinet in the room contained a real (disabled) gun with a sensor counting trigger pulls. Recordings were coded for the time spent holding the gun and in aggressive play. Data were collected from July 15, 2015, through January 1, 2016, and analyzed using generalized estimating equations (Tweedie log-link for time spent holding the gun; Poisson log-link for pulling the trigger). The 2 main outcomes were time spent holding the gun and the number of trigger pulls. Control variables included sex, age, trait aggressiveness, exposure to violent media, interest in guns, and number of guns at home. Among the 104 study participants (62 boys [59.6%] and 42 girls [40.4%]; mean (SD) age, 9.9 [1.5] years), the adjusted median number of trigger pulls among children who saw the movie containing guns was 2.8 (interquartile range [IQR], 0.2-2.8) compared with 0.01 (IQR, 0.01-0.2) among children who saw the movie not containing guns (adjusted odds ratio, 22.3; 95% CI, 6.0-83.4; P gun among children who saw a movie containing guns was 53.1 (IQR, 35.5-53.1) compared with 11.1 (IQR, 10.7-16.7) among children who saw the movie not containing guns (adjusted odds ratio, 3.0; 95% CI, 0.9-9.9; P = .07). Qualitative analyses on 4 pairs from each condition found that children who saw the movie containing guns also played more

Co-ordinated management of two underground gas facilities in aquifer

International Nuclear Information System (INIS)

D'Haussy, P.L.

1990-01-01

Coordinated management of two underground natural gas storage facilities which are approximately 10 km apart is described. The essential part of service installations allowing their operation is provided at a single location and is common to both facilities, which contributes to ensuring safety gas supply in France

Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

International Nuclear Information System (INIS)

Combs, S.K.; Milora, S.L.; Foust, C.R.; Gouge, M.J.; Fehling, D.T.; Sparks, D.O.

1988-01-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume (/ 3 for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of ∼3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications. 25 refs., 6 figs., 1 tab

God and Guns: Examining Religious Influences on Gun Control Attitudes in the United States

Directory of Open Access Journals (Sweden)

Stephen M. Merino

2018-06-01

Full Text Available Mass shootings in the United States have generated significant media coverage and public concern, invigorating debates over gun control. Media coverage and academic research on gun control attitudes and reactions to mass shootings have paid little attention to the role of religion. Recent research sheds light on the complex relationship between religion and guns, including higher rates of gun ownership and stronger opposition to gun control among white evangelical Protestants. Using nationally representative survey data, this study examines the relationship between religious identity, gun ownership, and support for a range of gun control policies, including proposed remedies for preventing mass shootings. Compared with individuals from other religious traditions, evangelical Protestants are most opposed to stricter gun control laws and enforcement, even with statistical controls for gun ownership and demographic characteristics. Rather, they favor individualistic solutions and putting more emphasis on religious values in their social surroundings. I discuss how these findings reflect the cultural tools evangelical Protestants use to construct their understandings of social problems, including gun violence, and the broader implications for gun policy in the United States.

Great gas plants : these five natural gas processing facilities demonstrate decades of top-flight technology

Energy Technology Data Exchange (ETDEWEB)

Byfield, M.

2010-07-15

The natural gas purification and pipeline sector is a major economic driver in Canada. Gas processing facilities are growing in number, and several large gas projects are being planned for future construction in the western provinces. This article outlined 5 gas plants in order to illustrate the sector's history and breadth in Canada. The Shell Jumping Pound gas complex was constructed in 1951 after a sulfur-rich gas discovery near Calgary in 1944. The Empress Straddle plant was built in 1971 in southeastern Alberta and is one of the largest single industrial consumers of electrical power in the province. The Fort Nelson gas processing plant is North America's largest sour gas processing facility. The Shell Caroline complex was built 1993. The Sable offshore energy project is located on the coast of Nova Scotia to handle gas produced from the Thebaud wells. A consortium is now considering the development of new gas fields in the Sable area. 5 figs.

Spectral diagnostic of plasma in the coaxial gun

International Nuclear Information System (INIS)

Bacilek, J.; Hruska, J.; Kubes, P.

1975-01-01

Plasma ejected from a coaxial plasma gun was investigated spectroscopically. The coaxial gun consisted of two copper coaxial electrodes 57 and 100 mm in diameter, the length of the central electrode being 67 mm. The gun was fed by a 11 μF capacitor bank of 16 kV operating voltage. Hydrogen, helium and air were used as working gases. The emission spectra were recorded with spectrograph ISP-51 and with a monochromator-photomultiplier system. The plasma density reached its maximum of 4x10 15 cm -3 with the ejecting voltage applied some 20 to 30 μs after the gas injection. At this moment also the spectral lines of electrode material were most intensive. The electron temperature calculated from the presence of spectral lines of OII, CII and NII was about 2 eV. The velocity of fast hydrogen ions was 4x10 7 cmsec -1 calculated from the Hsub(β) line. (J.U.)

Development of high velocity gas gun with a new trigger system-numerical analysis

Science.gov (United States)

Husin, Z.; Homma, H.

2018-02-01

In development of high performance armor vests, we need to carry out well controlled experiments using bullet speed of more than 900 m/sec. After reviewing trigger systems used for high velocity gas guns, this research intends to develop a new trigger system, which can realize precise and reproducible impact tests at impact velocity of more than 900 m/sec. A new trigger system developed here is called a projectile trap. A projectile trap is placed between a reservoir and a barrel. A projectile trap has two functions of a sealing disk and triggering. Polyamidimide is selected for the trap material and dimensions of the projectile trap are determined by numerical analysis for several levels of launching pressure to change the projectile velocity. Numerical analysis results show that projectile trap designed here can operate reasonably and stresses caused during launching operation are less than material strength. It means a projectile trap can be reused for the next shooting.

Gun Theft and Crime.

Science.gov (United States)

Cook, Philip J

2018-06-01

Some law enforcement officials and other observers have asserted that theft is the primary source of guns to crime. In fact, the role of theft in supplying the guns used in robbery, assault, and murder is unknown, and current evidence provides little guidance about whether an effective program to reduce gun theft would reduce gun violence. The current article analyzes publicly available national data on gun theft together with a unique data set for Chicago. The results tend to support a conclusion that stolen guns play only a minor role in crime. First, publicly available data are used to calculate that thefts are only about 1% of all gun transactions nationwide. Second, an analysis of original data from Chicago demonstrates that less than 3% of crime guns recovered by the police have been reported stolen to the Chicago Police Department (CPD). If a gun is reported stolen, there is a 20% chance that it will be recovered, usually in conjunction with an arrest for illegal carrying. Less than half of those picked up with a stolen gun have a criminal record that includes violent offenses. Third, results from surveys of convicted criminals, both nationally and in Chicago, suggest that it is rare for respondents to have stolen the gun used in their most recent crime. The data on which these results are based have various shortcomings. A research agenda is proposed that would provide more certainty about the role of theft.

Guns and Violence. Current Controversies.

Science.gov (United States)

Kim, Henny H., Ed.

This book focuses on gun violence and gun control, presenting both sides of arguments about firearms ownership and gun control. Each of five chapters poses a question about gun control and provides answers for both sides of the question. The following essays are included: (1) "Gun Violence Is Becoming an Epidemic" (Bob Herbert); (2) "Gun Violence…

Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

Energy Technology Data Exchange (ETDEWEB)

Kelly, Kay L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ramsden, Margo M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gonzales, John E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lynch, Lauren [National Renewable Energy Lab. (NREL), Golden, CO (United States); Coale, Bob [Gladstein, Neandross & Associates, Santa Monica, CA (United States); Kohout, Jarrod [Gladstein, Neandross & Associates, Santa Monica, CA (United States)

2017-09-28

To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. The hazard presented by liquid fuels, such as gasoline and diesel, results from the spillage of these liquids and subsequent ignition of vapors, causing a fire or explosion. Facilities that maintain liquid-fueled vehicles and implement appropriate safety measures are protected with ventilation systems designed to capture liquid fuel vapors at or near floor level. To minimize the potential for ignition in the event of a spill, receptacles, electrical fixtures, and hot-work operations, such as welding, are located outside of these areas. Compressed natural gas (CNG) is composed of methane with slight amounts of heavier simple hydrocarbons. Maintenance facilities that maintain CNG vehicles indoors must be protected against fire and explosion. However, the means of ensuring safety are different from those employed for liquid fuels because of the gaseous nature of methane and the fact that it is lighter than air. Because CNG is lighter than air, a release will rise to the ceiling of the maintenance facility and quickly dissipate rather than remaining at or near floor level like liquid fuel vapors. Although some of the means of protection for CNG vehicle maintenance facilities are similar to those used for liquid-fueled vehicles (ventilation and elimination of ignition sources), the types and placement of the protection equipment are different because of the behavior of the different fuels. The nature of gaseous methane may also require additional safeguards, such as combustible

High Precision Motion Control System for the Two-Stage Light Gas Gun at the Dynamic Compression Sector

Science.gov (United States)

Zdanowicz, E.; Guarino, V.; Konrad, C.; Williams, B.; Capatina, D.; D'Amico, K.; Arganbright, N.; Zimmerman, K.; Turneaure, S.; Gupta, Y. M.

2017-06-01

The Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS), located at Argonne National Laboratory (ANL), has a diverse set of dynamic compression drivers to obtain time resolved x-ray data in single event, dynamic compression experiments. Because the APS x-ray beam direction is fixed, each driver at DCS must have the capability to move through a large range of linear and angular motions with high precision to accommodate a wide variety of scientific needs. Particularly challenging was the design and implementation of the motion control system for the two-stage light gas gun, which rests on a 26' long structure and weighs over 2 tons. The target must be precisely positioned in the x-ray beam while remaining perpendicular to the gun barrel axis to ensure one-dimensional loading of samples. To accommodate these requirements, the entire structure can pivot through 60° of angular motion and move 10's of inches along four independent linear directions with 0.01° and 10 μm resolution, respectively. This presentation will provide details of how this system was constructed, how it is controlled, and provide examples of the wide range of x-ray/sample geometries that can be accommodated. Work supported by DOE/NNSA.

Development of a Plasma Streaming System for the Mirror Fusion Test Facility

International Nuclear Information System (INIS)

Holdsworth, T.; Clark, R.N.; McCotter, R.E.; Rossow, T.L.; Cruz, G.E.

1979-01-01

The Plasma Streaming System (PSS) is an essential portion of the Mirror Fusion Test Facility (MFTF), scheduled for completion in October 1981. The PSS will develop a plasma density of at least 2 x 10 12 particles/cm 3 at the MFTF magnet centerline by injecting particles along the field lines. The plasma will have a midplane plasma radius as large as 40 cm with variable plasma particle energy and beam geometry. Minimum amounts of impurities will be injected, with emphasis on minimizing high Z materials. Each of the 60 PSS units will consist of a gun magnet assembly (GMA) and a power supply. Each GMA consists of a plasma streaming gun, a pulse magnet that provides variable beam shaping, and a fast reaction pulse gas valve

Approach to the energetic coaxial gun of the steady-state mode operation

International Nuclear Information System (INIS)

Hirano, Kei-ichi

1993-01-01

Behaviors of a coaxial plasma gun operated in a steady-state mode have been studied. It is shown that the gun has potentialities to yield an energetic plasma beam, if a supersonic plasma flow is supplied instead of a neutral gas and if shorting out of the Hall potential is minimized on the surfaces of the electrodes. The former is necessary because a electromagnetic force chokes the subsonic flow appearing in the ionizing zone of the inlet gas. The latter is achieved if the electrodes are segmented into many insulated short elements along the axis. The required minimum number of the segmentation is estimated by the newly developed model based on the boundary layer concept. (author)

Gun control saves lives

African Journals Online (AJOL)

gun control legislation. One study estimated that more than 4 500 lives were saved across five SA cities from 2001 to 2005.[5] Pro-gun interest groups seeking to promote gun ownership and diffusion have attacked these findings, suggesting that stricter gun control was only enacted in 2004 following the publication of ...

RF study and 3-D simulations of a side-coupling thermionic RF-gun

Energy Technology Data Exchange (ETDEWEB)

Rimjaem, S., E-mail: sakhorn.rimjaem@cmu.ac.th [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand); Kusoljariyakul, K.; Thongbai, C. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand)

2014-02-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012{sup ©}. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

RF Processing Experience with the GTF Prototype RF Gun

International Nuclear Information System (INIS)

Schmerge, J.F.

2010-01-01

The SSRL Gun Test Facility (GTF) was built to develop a high brightness electron injector for the LCLS and has been operational since 1996. A total of five different metal cathodes (4 Cu and 1 Mg) have been installed on the GTF gun. The rf processing history with the different cathodes will be presented including peak field achieved at the cathode. The LCLS gun is intended to operate at 120 MV/m and fields up to 140 MV/m have been achieved in the GTF gun. After installing a new cathode the number of rf pulses required to reach 120 MV/m is approximately 5-10 million. Total emitted dark current and Fowler Nordheim plots are also shown over the life of the cathode. The GTF photo-injector gun is an S-band standing-wave structure, with two resonant cavities and an intervening thick washer (Figure 1). The flat, back wall of the first cavity is a copper plate that serves as photocathode when illuminated with ultraviolet light from a pulsed, high-power laser. RF power enters the gun through an iris on the outer wall of the second cavity, and is coupled to the first through the axial opening of the washer. The first cavity is often referred to as a half cell, because its full-cell length has been truncated by the cathode plate and the second cavity is called the full cell. The gun is designed to operate in a π mode, with the peak field on axis in each cell approximately equal. The maximum in the half cell occurs at the cathode, and in the full cell near the center of the cavity. The field profile and tuning procedures are discussed in a separate tech note (1).

The Influence of the Axial Magnetic Field Upon-the Coaxial Plasma Gun Parameters

International Nuclear Information System (INIS)

El-Aragi, G.M.; EL-Demrdash, A.

2001-01-01

This study concerns with the influence of an applied axial magnetic field upon the electrical parameters of a coaxial plasma gun device. The experimental results are investigated with 0.5 KJ plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied

Cerenkov Radiator Driven by a Superconducting RF Electron Gun

International Nuclear Information System (INIS)

Poole, B.R.; Harris, J.R.

2011-01-01

The Naval Postgraduate School (NPS), Niowave, Inc., and Boeing have recently demonstrated operation of the first superconducting RF electron gun based on a quarter wave resonator structure. In preliminary tests, this gun has produced 10 ps long bunches with charge in excess of 78 pC, and with beam energy up to 396 keV. Initial testing occurred at Niowave's Lansing, MI facility, but the gun and diagnostic beam line are planned for installation in California in the near future. The design of the diagnostic beam line is conducive to the addition of a Cerenkov radiator without interfering with other beam line operations. Design and simulations of a Cerenkov radiator, consisting of a dielectric lined waveguide will be presented. The dispersion relation for the structure is determined and the beam interaction is studied using numerical simulations. The characteristics of the microwave radiation produced in both the short and long bunch regimes will be presented.

Gun Sales. Firearm Facts.

Science.gov (United States)

Duker, Laurie, Ed.

Minimal federal regulations on firearm sales have facilitated the proliferation of guns, gun owners, and gun dealers in the United States. This fact sheet offers data on the growing number of firearm dealers, the relative ease of obtaining and keeping a license to sell guns from the Federal Bureau of Alcohol, Tobacco, and Firearms, the lack of…

Analysis of Gas Vent System in Overseas LILW Disposal Facilities

Energy Technology Data Exchange (ETDEWEB)

Kim, Ju Yub; Kim, Ju Youl [FNC Technology Co., Yongin (Korea, Republic of); Jung, Hae Ryong; Ha, Jae Chul [Korea Radioactive Waste Management Corporation, Daejeon (Korea, Republic of)

2012-05-15

A Low- and Intermediate-Level Radioactive Waste (LILW) disposal facility is currently under construction in Korea. It is located in the aquifer, 80{approx}130 m below the ground surface. Thus, it is expected that disposal facility will be saturated after closure and various gases will be generated from metal corrosion, microbial degradation of organic materials and radiolysis. Generated gases will move up to the upper part of the silo, and it will increase the pressure of the silo. Since the integrity of the engineered barrier could be damaged, development of effective gas vent system which can prevent the gas accumulation in the silo is essential. In order to obtain basic data needed to develop site-specific gas vent system, gas vent systems of Sweden, Finland and Switzerland, which have the disposal concept of underground facility, were analyzed

Development process of muzzle flows including a gun-launched missile

Directory of Open Access Journals (Sweden)

Zhuo Changfei

2015-04-01

Full Text Available Numerical investigations on the launch process of a gun-launched missile from the muzzle of a cannon to the free-flight stage have been performed in this paper. The dynamic overlapped grids approach are applied to dealing with the problems of a moving gun-launched missile. The high-resolution upwind scheme (AUSMPW+ and the detailed reaction kinetics model are adopted to solve the chemical non-equilibrium Euler equations for dynamic grids. The development process and flow field structure of muzzle flows including a gun-launched missile are discussed in detail. This present numerical study confirms that complicated transient phenomena exist in the shortly launching stages when the gun-launched missile moves from the muzzle of a cannon to the free-flight stage. The propellant gas flows, the initial environmental ambient air flows and the moving missile mutually couple and interact. A complete structure of flow field is formed at the launching stages, including the blast wave, base shock, reflected shock, incident shock, shear layer, primary vortex ring and triple point.

Valuation of gas stored in salt cavern facilities

Energy Technology Data Exchange (ETDEWEB)

Bond, Michael A. [St. Mary' s University, TX (United States); Grant, Floyd H. [Purdue University, IN (United States)

2008-07-01

Since natural gas production is relatively inelastic towards demand in the short term, underground storage is used as a buffer against periods of high demand. Of the three most common storage facility types, depleted reservoirs, aquifers and manmade salt caverns, the latter is the most costly to develop. The challenge then is to maximize profits through efficient operation, well-timed injection and withdrawal of gas. The valuation of a commodity in storage is a challenging problem and has been the subject of study for decades. We investigate selected existing valuation approaches and look for ways to leverage salt-cavern-specific physical characteristics for financial advantage. The basis for our valuation is the Black-Scholes model for pricing options. Then, applying Monte-Carlo methods and simulation, we model combinations of characteristics in multi-cavern facilities and their impact on profitability. We describe the theory behind our work and our analytical framework and provide numerical results of our analysis. Our approach offers increased efficiency in salt-cavern gas storage facility operations. (author)

Racism, gun ownership and gun control: biased attitudes in US whites may influence policy decisions.

Science.gov (United States)

O'Brien, Kerry; Forrest, Walter; Lynott, Dermot; Daly, Michael

2013-01-01

Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US whites. Explanatory variables known to be related to gun ownership and gun control opposition (i.e., age, gender, education, income, conservatism, anti-government sentiment, southern vs. other states, political identification) were entered in logistic regression models, along with measures of racism, and the stereotype of blacks as violent. Outcome variables included; having a gun in the home, opposition to bans on handguns in the home, support for permits to carry concealed handguns. After accounting for all explanatory variables, logistic regressions found that for each 1 point increase in symbolic racism there was a 50% increase in the odds of having a gun at home. After also accounting for having a gun in the home, there was still a 28% increase in support for permits to carry concealed handguns, for each one point increase in symbolic racism. The relationship between symbolic racism and opposition to banning handguns in the home (OR1.27 CI 1.03,1.58) was reduced to non-significant after accounting for having a gun in the home (OR1.17 CI.94,1.46), which likely represents self-interest in retaining property (guns). Symbolic racism was related to having a gun in the home and opposition to gun control policies in US whites. The findings help explain US whites' paradoxical attitudes towards gun ownership and gun control. Such attitudes may adversely influence US gun control policy debates and decisions.

Renewal of KU-FEL Facility

CERN Document Server

Kii, Toshiteru; Masuda, Kai; Murakami, Shio; Ohgaki, Hideaki; Yamazaki, Tetsuo; Yoshikawa, Kiyoshi; Zen, Heishun

2004-01-01

Users demands to a high power tunable IR laser are increasing in Japan in energy-related science, such as basic study of high-efficiency solar cells, generation of new energy source of alcohol and/or H2 from polluted gas, and separation of DNA and/or RNA. To satisfy these demands, we decided to renew our FEL facility more user friendly and to operate more flexibly. Construction and fundamental studies on the KU-FEL have been carried out at a building of Institute of Chemical Research where few other accelerators are operating. Therefore, available machine time for our experiments is quite limited. We are now modifying the room by adding concrete walls of 2-m thickness and some space for users will be available. The present FEL system will be moved to the room A photocathode RF-gun system will be nearly added to the system and the present thermionic RF-gun will be used ternatively according to the demands of users. The photocathode material will be Cs2Te. The room with the shielding will be completed in June, ...

Simulations of the BNL/SLAC/UCLA 1.6 cell emittance compensated photocathode RF gun low energy beam line

International Nuclear Information System (INIS)

Palmer, D.T.; Miller, R.H.; Winick, H.

1995-01-01

A dedicated low energy (2 to 10 MeV) experimental beam line is now under construction at Brookhaven National Laboratories Accelerator Test Facility (BNL/ATF) for photocathode RF gun testing and photoemission experiments. The design of the experimental line, using the 1.6 cell photocathode RF gun developed by the BNL/SLAC/UCLA RF gun collaboration is presented. Detailed beam dynamics simulations were performed for the 1.6 cell RF gun injector using a solenoidal emittance compensation technique. An experimental program for testing the 1.6 cell RF gun is presented. This program includes beam loading caused by dark current, higher order mode field measurements, integrated and slice emittance measurements using a pepper-pot and RF kicker cavity

Distributed Supply Coordination for Power-to-Gas Facilities Embedded in Energy Grids

NARCIS (Netherlands)

Alkano, Desti; Scherpen, Jacquelien M. A.

This paper considers hydrogen and renewable electricity from power-to-gas (PtG) facilities supplied to a gas grid, a mobility sector, and a power grid. The PtG facilities are equipped with hydrogen buffers and fuel cells. The goal is to maximize the expected profit of PtG facilities without

Electromagnetic compression gun for hypervelocity projectile acceleration

International Nuclear Information System (INIS)

Woo, J.T.

1987-01-01

The rapid acceleration of projectiles to very high velocities has applications in many areas. The general requirements for an effective system is simplicity, reliability, compactness and good efficiency. The authors developed a concept by using electromagnetic forces to compressionally heat a plasma to high temperature and pressure to serve as the propellant for the acceleration of projectiles. The concept shares the simplicity of the light gas gun, but because of the high temperature of the propellant, is capable of significantly higher performance. Unlike the electrothermal gun approach to raise the propellant temperature by resistive heating, the electromagnetic concept is more efficient at higher temperatures. Operationally, the concept resembles a railgun in requiring a large pulsed current to drive the system. However, the current flow in this case is entirely external to the gun barrel and is axisymmetric. Therefore, many of the problems associated with railgun operations are avoided. Furthermore, because the current channel is external, there is also greater flexibility in the choice of load impedance to match to the power supply. The concept can also be generalized to a multi-stage regenerative system driven by a pulse forming network to resemble a coaxial accelerator

Racism, gun ownership and gun control: biased attitudes in US whites may influence policy decisions.

Directory of Open Access Journals (Sweden)

Kerry O'Brien

Full Text Available OBJECTIVE: Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty. This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. METHOD: The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US whites. Explanatory variables known to be related to gun ownership and gun control opposition (i.e., age, gender, education, income, conservatism, anti-government sentiment, southern vs. other states, political identification were entered in logistic regression models, along with measures of racism, and the stereotype of blacks as violent. Outcome variables included; having a gun in the home, opposition to bans on handguns in the home, support for permits to carry concealed handguns. RESULTS: After accounting for all explanatory variables, logistic regressions found that for each 1 point increase in symbolic racism there was a 50% increase in the odds of having a gun at home. After also accounting for having a gun in the home, there was still a 28% increase in support for permits to carry concealed handguns, for each one point increase in symbolic racism. The relationship between symbolic racism and opposition to banning handguns in the home (OR1.27 CI 1.03,1.58 was reduced to non-significant after accounting for having a gun in the home (OR1.17 CI.94,1.46, which likely represents self-interest in retaining property (guns. CONCLUSIONS: Symbolic racism was related to having a gun in the home and opposition to gun control policies in US whites. The findings help explain US whites' paradoxical attitudes towards gun ownership and gun control. Such attitudes may adversely influence US gun control policy debates and decisions.

Racism, Gun Ownership and Gun Control: Biased Attitudes in US Whites May Influence Policy Decisions

Science.gov (United States)

O’Brien, Kerry; Forrest, Walter; Lynott, Dermot; Daly, Michael

2013-01-01

Objective Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. Method The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US whites. Explanatory variables known to be related to gun ownership and gun control opposition (i.e., age, gender, education, income, conservatism, anti-government sentiment, southern vs. other states, political identification) were entered in logistic regression models, along with measures of racism, and the stereotype of blacks as violent. Outcome variables included; having a gun in the home, opposition to bans on handguns in the home, support for permits to carry concealed handguns. Results After accounting for all explanatory variables, logistic regressions found that for each 1 point increase in symbolic racism there was a 50% increase in the odds of having a gun at home. After also accounting for having a gun in the home, there was still a 28% increase in support for permits to carry concealed handguns, for each one point increase in symbolic racism. The relationship between symbolic racism and opposition to banning handguns in the home (OR1.27 CI 1.03,1.58) was reduced to non-significant after accounting for having a gun in the home (OR1.17 CI.94,1.46), which likely represents self-interest in retaining property (guns). Conclusions Symbolic racism was related to having a gun in the home and opposition to gun control policies in US whites. The findings help explain US whites’ paradoxical attitudes towards gun ownership and gun control. Such attitudes may adversely influence US gun control policy debates and decisions. PMID:24204867

Gun power source for electron gun of 3 MeV DC accelerator

International Nuclear Information System (INIS)

Dewangan, S.; Sharma, D.K.; Nanu, K.

2011-01-01

In DC electron beam accelerator electron gun is situated at high voltage terminal which requires constant power irrespective of beam energy. Floating power source is required for gun. This paper describes the scheme of static gun power source derived from parallel coupled voltage multiplier column. (author)

Electron guns for accelerators

International Nuclear Information System (INIS)

Rangarajan, L.M.; Mahadevan, S.; Ramamurthi, S.S.

1995-01-01

The high voltage, high current electron guns developed elsewhere for Linacs are based on cathode pulsing with direct emitting cathodes. Our grid pulsed triode gun employs indirect emitting cathode pellet under electron bombardment or a direct cathode emitter. Electron beam from the gun is injected to the accelerator guide at 40 kV and pulse duration is 2.8μsec. The gun is limited to axially symmetric geometry and electron optical design is optimized by computer programming. The gun with a water cooled Faraday cup is connected to a vacuum system comprising of a sputter ion pump and sorption pump. Working pressure is 1x10 -6 Pa. Gun is designed to be baked as an assembly at temperatures of 400 degC while vacuum processing. Materials are therefore restricted to refractory metals, SS, OFHC copper and all the electrodes are housed inside a ceramic tube. Lower Z graphite is used as a base material of Faraday cup. Grid is non-intercepting modulator anode, a new feature introduced, as compared to meshed grid system by others. CAT gun delivers 160 mA current pulses at 40 kV and its working characteristics such as perveance, emittance and beam radius compare well with SLAC and Hermosa guns. The above guns can be used for electron beam machines such as medical Linacs, industrial accelerators and EB welding equipment. (author). 2 refs., 2 figs

Carbon plasma gun

International Nuclear Information System (INIS)

Mendel, C.W. Jr.; Zagar, D.M.; Mills, G.S.; Humphries, S. Jr.; Goldstein, S.A.

1980-01-01

A family of plasma guns supplying highly ionized carbon plasma is described. The guns are simple and inexpensive to construct and are pulsed by small capacitor banks of a few hundred joules. The output consists of 10 17 --10 18 multiply ionized carbon ions traveling at about 10 7 cm/s. Neutral output is very low and arrives well after the ionized carbon. The guns and pulsers are very reliable

Carbon Nanotube Electron Gun

Science.gov (United States)

Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

2013-01-01

An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

Advanced diagnostics for impact-flash spectroscopy on light-gas guns.

Energy Technology Data Exchange (ETDEWEB)

Breiland, William George; Reinhart, William Dodd; Miller, Paul Albert; Brown, Justin L.; Thornhill, Tom Finley, III (,; ); Mangan, Michael A.; Shaner, Eric Arthur; Chhabildas, Lalit Chandra; Grine, Albert D.; Wanke, Michael Clement; Alexander, C. Scott

2007-03-01

This study is best characterized as new technology development for implementing new sensors to investigate the optical characteristics of a rapidly expanding debris cloud resulting from hypervelocity impact regimes of 7 to 11 km/s. Our gas guns constitute a unique test bed that match operational conditions relevant to hypervelocity impact encountered in space engagements. We have demonstrated the use of (1) terahertz sensors, (2) silicon diodes for visible regimes, (3) germanium and InGaAs sensors for the near infrared regimes, and (4) the Sandia lightning detectors which are similar to the silicon diodes described in 2. The combination and complementary use of all these techniques has the strong potential of ''thermally'' characterizing the time dependent behavior of the radiating debris cloud. Complementary spectroscopic measurements provide temperature estimates of the impact generated debris by fitting its spectrum to a blackbody radiation function. This debris is time-dependent as its transport/expansion behavior is changing with time. The rapid expansion behavior of the debris cools the cloud rapidly, changing its thermal/temperature characteristics with time. A variety of sensors that span over a wide spectrum, varying from visible regime to THz frequencies, now gives us the potential to cover the impact over a broader temporal regime starting from high pressures (Mbar) high-temperatures (eV) to low pressures (mbar) low temperatures (less than room temperature) as the debris expands and cools.

Gun Violence, Mental Illness, And Laws That Prohibit Gun Possession: Evidence From Two Florida Counties.

Science.gov (United States)

Swanson, Jeffrey W; Easter, Michele M; Robertson, Allison G; Swartz, Marvin S; Alanis-Hirsch, Kelly; Moseley, Daniel; Dion, Charles; Petrila, John

2016-06-01

Gun violence kills about ninety people every day in the United States, a toll measured in wasted and ruined lives and with an annual economic price tag exceeding $200 billion. Some policy makers suggest that reforming mental health care systems and improving point-of-purchase background checks to keep guns from mentally disturbed people will address the problem. Epidemiological research shows that serious mental illness contributes little to the risk of interpersonal violence but is a strong factor in suicide, which accounts for most firearm fatalities. Meanwhile, the effectiveness of gun restrictions focused on mental illness remains poorly understood. This article examines gun-related suicide and violent crime in people with serious mental illnesses, and whether legal restrictions on firearm sales to people with a history of mental health adjudication are effective in preventing gun violence. Among the study population in two large Florida counties, we found that 62 percent of violent gun crime arrests and 28 percent of gun suicides involved individuals not legally permitted to have a gun at the time. Suggested policy reforms include enacting risk-based gun removal laws and prohibiting guns from people involuntarily detained in short-term psychiatric hospitalizations. Project HOPE—The People-to-People Health Foundation, Inc.

Environmental impacts of air-gun surveys on glass sponges : final report

Energy Technology Data Exchange (ETDEWEB)

Tunnicliffe, V; Yahel, G [Victoria Univ., Victoria, BC (Canada). Dept. of Biology; Chapman, R; Wilmut, M [Victoria Univ., Victoria, BC (Canada). School of Earth and Ocean Sciences

2008-09-15

Air-gun surveys associated with the oil and gas exploration in the Queen Charlotte Basin will insonify the seafloor with broadband, high intensity noise, exposing the glass sponge reef systems of that area to acoustic impacts. Tissue integrity and behaviour of marine animals can be affected by the acoustic harassment of water propagated vibration. This paper examined the effects of acoustic noise on the behaviour of glass sponges. The purpose of the study was to test the hypothesis that the acoustic vibration produced by a small, surface operated air gun would not alter the normal pattern of sponge feeding activities. The paper described the methods, with particular reference to the study site; sponge pumping rate; and acoustic effects on sponge pumping. Results were presented for ambient conditions; air gun shots; sponge pumping responses to air gun shots; and correlation of sponge response and ambient current. The question of whether the sponge's excurrent flow responds to the pressure from a series of air-gun shots was addressed by a statistical analysis over all the excurrent data from the experiment. It was concluded that there is little or no evidence that the acoustic pressure from the shots influences the physiological functions of the sponge. 22 refs., 2 tabs., 11 figs.

Environmental impacts of air-gun surveys on glass sponges : final report

Energy Technology Data Exchange (ETDEWEB)

Tunnicliffe, V.; Yahel, G. [Victoria Univ., Victoria, BC (Canada). Dept. of Biology; Chapman, R.; Wilmut, M. [Victoria Univ., Victoria, BC (Canada). School of Earth and Ocean Sciences

2008-09-15

Air-gun surveys associated with the oil and gas exploration in the Queen Charlotte Basin will insonify the seafloor with broadband, high intensity noise, exposing the glass sponge reef systems of that area to acoustic impacts. Tissue integrity and behaviour of marine animals can be affected by the acoustic harassment of water propagated vibration. This paper examined the effects of acoustic noise on the behaviour of glass sponges. The purpose of the study was to test the hypothesis that the acoustic vibration produced by a small, surface operated air gun would not alter the normal pattern of sponge feeding activities. The paper described the methods, with particular reference to the study site; sponge pumping rate; and acoustic effects on sponge pumping. Results were presented for ambient conditions; air gun shots; sponge pumping responses to air gun shots; and correlation of sponge response and ambient current. The question of whether the sponge's excurrent flow responds to the pressure from a series of air-gun shots was addressed by a statistical analysis over all the excurrent data from the experiment. It was concluded that there is little or no evidence that the acoustic pressure from the shots influences the physiological functions of the sponge. 22 refs., 2 tabs., 11 figs.

Femtosecond precision measurement of laser–rf phase jitter in a photocathode rf gun

International Nuclear Information System (INIS)

Shi, Libing; Zhao, Lingrong; Lu, Chao; Jiang, Tao; Liu, Shengguang; Wang, Rui; Zhu, Pengfei; Xiang, Dao

2017-01-01

We report on the measurement of the laser–rf phase jitter in a photocathode rf gun with femtosecond precision. In this experiment four laser pulses with equal separation are used to produce electron bunch trains; then the laser–rf phase jitter is obtained by measuring the variations of the electron bunch spacing with an rf deflector. Furthermore, we show that when the gun and the deflector are powered by the same rf source, it is possible to obtain the laser–rf phase jitter in the gun through measurement of the beam–rf phase jitter in the deflector. Based on these measurements, we propose an effective time-stamping method that may be applied in MeV ultrafast electron diffraction facilities to enhance the temporal resolution.

Femtosecond precision measurement of laser–rf phase jitter in a photocathode rf gun

Energy Technology Data Exchange (ETDEWEB)

Shi, Libing; Zhao, Lingrong; Lu, Chao; Jiang, Tao; Liu, Shengguang; Wang, Rui; Zhu, Pengfei; Xiang, Dao, E-mail: dxiang@sjtu.edu.cn

2017-03-21

We report on the measurement of the laser–rf phase jitter in a photocathode rf gun with femtosecond precision. In this experiment four laser pulses with equal separation are used to produce electron bunch trains; then the laser–rf phase jitter is obtained by measuring the variations of the electron bunch spacing with an rf deflector. Furthermore, we show that when the gun and the deflector are powered by the same rf source, it is possible to obtain the laser–rf phase jitter in the gun through measurement of the beam–rf phase jitter in the deflector. Based on these measurements, we propose an effective time-stamping method that may be applied in MeV ultrafast electron diffraction facilities to enhance the temporal resolution.

Compressed Gas Safety for Experimental Fusion Facilities

Energy Technology Data Exchange (ETDEWEB)

Lee C. Cadwallader

2004-09-01

Experimental fusion facilities present a variety of hazards to the operators and staff. There are unique or specialized hazards, including magnetic fields, cryogens, radio frequency emissions, and vacuum reservoirs. There are also more general industrial hazards, such as a wide variety of electrical power, pressurized air, and cooling water systems in use, there are crane and hoist loads, working at height, and handling compressed gas cylinders. This paper outlines the projectile hazard assoicated with compressed gas cylinders and mthods of treatment to provide for compressed gas safety. This information should be of interest to personnel at both magnetic and inertial fusion experiments.

Experimental facilities for gas-cooled reactor safety studies. Task group on Advanced Reactor Experimental Facilities (TAREF)

International Nuclear Information System (INIS)

2009-01-01

In 2007, the NEA Committee on the Safety of Nuclear Installations (CSNI) completed a study on Nuclear Safety Research in OECD Countries: Support Facilities for Existing and Advanced Reactors (SFEAR) which focused on facilities suitable for current and advanced water reactor systems. In a subsequent collective opinion on the subject, the CSNI recommended to conduct a similar exercise for Generation IV reactor designs, aiming to develop a strategy for ' better preparing the CSNI to play a role in the planned extension of safety research beyond the needs set by current operating reactors'. In that context, the CSNI established the Task Group on Advanced Reactor Experimental Facilities (TAREF) in 2008 with the objective of providing an overview of facilities suitable for performing safety research relevant to gas-cooled reactors and sodium fast reactors. This report addresses gas-cooled reactors; a similar report covering sodium fast reactors is under preparation. The findings of the TAREF are expected to trigger internationally funded CSNI projects on relevant safety issues at the key facilities identified. Such CSNI-sponsored projects constitute a means for efficiently obtaining the necessary data through internationally co-ordinated research. This report provides an overview of experimental facilities that can be used to carry out nuclear safety research for gas-cooled reactors and identifies priorities for organizing international co-operative programmes at selected facilities. The information has been collected and analysed by a Task Group on Advanced Reactor Experimental Facilities (TAREF) as part of an ongoing initiative of the NEA Committee on the Safety of Nuclear Installations (CSNI) which aims to define and to implement a strategy for the efficient utilisation of facilities and resources for Generation IV reactor systems. (author)

Sanoli Gun

Indian Academy of Sciences (India)

Home; Journals; Proceedings – Mathematical Sciences. Sanoli Gun. Articles written in Proceedings – Mathematical Sciences. Volume 119 Issue 3 June 2009 pp 275-281. Remarks on some Zero-Sum Theorems · S D Adhikari Sanoli Gun Purusottam Rath · More Details Abstract Fulltext PDF. In the present paper, we give a ...

Large Bore Powder Gun Qualification (U)

Energy Technology Data Exchange (ETDEWEB)

Rabern, Donald A. [Los Alamos National Laboratory; Valdiviez, Robert [Los Alamos National Laboratory

2012-04-02

A Large Bore Powder Gun (LBPG) is being designed to enable experimentalists to characterize material behavior outside the capabilities of the NNSS JASPER and LANL TA-55 PF-4 guns. The combination of these three guns will create a capability to conduct impact experiments over a wide range of pressures and shock profiles. The Large Bore Powder Gun will be fielded at the Nevada National Security Site (NNSS) U1a Complex. The Complex is nearly 1000 ft below ground with dedicated drifts for testing, instrumentation, and post-shot entombment. To ensure the reliability, safety, and performance of the LBPG, a qualification plan has been established and documented here. Requirements for the LBPG have been established and documented in WE-14-TR-0065 U A, Large Bore Powder Gun Customer Requirements. The document includes the requirements for the physics experiments, the gun and confinement systems, and operations at NNSS. A detailed description of the requirements is established in that document and is referred to and quoted throughout this document. Two Gun and Confinement Systems will be fielded. The Prototype Gun will be used primarily to characterize the gun and confinement performance and be the primary platform for qualification actions. This gun will also be used to investigate and qualify target and diagnostic modifications through the life of the program (U1a.104 Drift). An identical gun, the Physics Gun, will be fielded for confirmatory and Pu experiments (U1a.102D Drift). Both guns will be qualified for operation. The Gun and Confinement System design will be qualified through analysis, inspection, and testing using the Prototype Gun for the majority of process. The Physics Gun will be qualified through inspection and a limited number of qualification tests to ensure performance and behavior equivalent to the Prototype gun. Figure 1.1 shows the partial configuration of U1a and the locations of the Prototype and Physics Gun/Confinement Systems.

18 CFR 157.212 - Synthetic and liquefied natural gas facilities.

Science.gov (United States)

2010-04-01

... natural gas facilities. 157.212 Section 157.212 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER NATURAL GAS ACT APPLICATIONS FOR CERTIFICATES... 7 OF THE NATURAL GAS ACT Interstate Pipeline Blanket Certificates and Authorization Under Section 7...

Goods for Guns--the use of a gun buyback as an injury prevention/community education tool.

Science.gov (United States)

McGuire, Margaret; Manno, Mariann; Rook, Allison; Maranda, Louise; Renaud, Elizabeth; DeRoss, Anthony; Hirsh, Michael

2011-11-01

US children aged between 5 years and 14 years have a rate of gun-related homicide 17 times higher and a rate of gun-related suicide and unintentional firearm injury 10 times higher than other developed countries. Gun buyback programs have been criticized as ineffective interventions in decreasing violence. The Injury Free Coalition for Kids-Worcester (IFCK-W) Goods for Guns buyback is a multipronged approach to address these concerns and to reduce the number of firearms in the community. The IFCK-W buyback program is funded by corporate sponsors, grants, and individual donations. Citizens are instructed to transport guns, ammunition, and weapons safely to police headquarters on two Saturdays in December. Participants are guaranteed anonymity by the District Attorney's office and receive gift certificates for operable guns. Trained volunteers administer an anonymous survey to willing participants. Individuals who disclose having unsafely stored guns remaining at home receive educational counseling and trigger locks. Guns and ammunition are destroyed at a later time in a gun crushing ceremony. Since 2002, 1,861 guns (444 rifle/shotgun, 738 pistol/revolver, and 679 automatic/semiautomatic) have been collected at a cost of $99,250 (average, $53/gun). Seven hundred ten people have surrendered firearms, 534 surveys have been administered, and ≈ 75 trigger locks have been distributed per year. IFCK-W Goods for Guns is a relatively inexpensive injury prevention model program that removes unwanted firearms from homes, raises community awareness about gun safety, and provides high-risk individuals with trigger locks and educational counseling.

The Effects of Cueing and Framing on Youth Attitudes towards Gun Control and Gun Rights

Directory of Open Access Journals (Sweden)

Stephen Wu

2018-02-01

Full Text Available I analyze attitudes towards gun control from a recent survey of American high school students. For students who most closely identify as Republicans, cueing them to think about prior school shootings increases their agreement that armed staff in schools will improve safety and arming citizens will reduce risk of mass shootings. For those identifying as Democrats and Independents, providing them with selective information that certain states have loose gun control laws and low rates of gun violence makes them more supportive of gun rights. For Republicans, providing selective information that certain states have loose gun control laws and high rates of gun violence makes them less supportive of gun rights. These results suggest that emotional cues may exacerbate a priori biases, while informational cues may be more likely to change people’s minds about firearm policies.

Guns and Trafficking in Crack-Cocaine and Other Drug Markets

Science.gov (United States)

Felson, Richard B.; Bonkiewicz, Luke

2013-01-01

This article examines the relationship between gun possession and the nature of an offender's involvement in drug markets. The analyses are based on data obtained from drug offenders who participated in the 1997 Survey of Inmates of State and Federal Correctional Facilities. The authors find that participants in crack-cocaine markets are more…

Time-dependent plasma behavior triggered by a pulsed electron gun under conditions of beam-plasma-discharge

International Nuclear Information System (INIS)

Szuszczewicz, E.P.; Lin, C.S.

1982-01-01

This chapter reports on experiments whose purpose was to simulate spaceborne applications of energetic electron guns while exploring the ''in situ'' diagnostics of time-dependent beam-plasma behavior under pulsed electron gun conditions. Beam-plasma-discharge (BPD), the BPD afterglow that exists after gun-pulse termination, and the plasma decay process are considered. It is concluded that there is a rapid enhancement in plasma density as the gas turns on; that during the pulse-ON time a quasi-steady-state BPD can be maintained with characteristics identical with its dc counterpart; that in the period immediately following gun-pulse termination the plasma loss process is dominated by cross-field radial diffusion; and that the afterglow plasma is within + or -10% of being an isodensity contour

The case for moderate gun control.

Science.gov (United States)

DeGrazia, David

2014-03-01

In addressing the shape of appropriate gun policy, this essay assumes for the sake of discussion that there is a legal and moral right to private gun ownership. My thesis is that, against the background of this right, the most defensible policy approach in the United States would feature moderate gun control. The first section summarizes the American gun control status quo and characterizes what I call "moderate gun control." The next section states and rebuts six leading arguments against this general approach to gun policy. The section that follows presents a positive case for moderate gun control that emphasizes safety in the home and society as well as rights whose enforcement entails some limits or qualifications on the right to bear arms. A final section shows how the recommended gun regulations address legitimate purposes, rather than imposing arbitrary restrictions on gun rights, and offers concluding reflections.

Test facility for fast gas injections into a vessel filled with water

International Nuclear Information System (INIS)

Wilhelm, D.; Kirstahler, M.

1987-11-01

The Fast Gas Injection Facility (SGI) was set up to study the hydrodynamics during the expansion of a gas bubble into a vessel filled with water. The gas stored in a pressure vessel expands against gravity through a circular duct into a large cylindrical vessel partly with water. This report covers the description of the test facility and the data acquisition. Results of the first test series are added. (orig.) [de

An in-situ photocathode loading system for the SLC Polarized Electron Gun

International Nuclear Information System (INIS)

Kirby, R.E.; Collet, G.J.; Skarpaas, K.

1992-12-01

An ultra-high vacuum loadlock system capable of operating at high voltage has been added to the SLC Polarized Electron Gun. The unit incorporates facilities for heat cleaning, activating and measuring the quantum efficiency of photocathodes. A tray of up to four photocathodes can be exchanged without bringing the activation unit or gun up to atmosphere. Low voltage quantum efficiencies of 20% have been obtained for bulk GaAs at 633 nm and 6% for a 0.3 micron GaAs layer at 755 nm. Results for other cathodes as well as operational characteristics are discussed

ORELA electron guns

International Nuclear Information System (INIS)

Christian, O.W.; Lewis, T.A.

1981-09-01

The most recent information concerning the production and performance of ORELA electron guns is presented. Included are descriptions of procedures for gun fabrication, cathode conditioning and high voltage processing. Highlights of the performance characteristics are also included

RF Design of the LCLS Gun

International Nuclear Information System (INIS)

Limborg-Deprey, C.

2010-01-01

Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun (1), referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, dual rf feed, deformation tuning of the full cell, and field probes in both cells. Temporal shaping of the klystron pulse, to reduce the average power dissipated in the gun, has also been adopted. By increasing the mode separation, the amplitude of the 0-mode electric field on the cathode decreases from 10% of the peak on axis field for the prototype gun to less than 3% for the LCLS gun for the steady state fields. Beam performance is improved as shown by the PARMELA simulations. The gun should be designed to accept a future load lock system. Modifications follow the recommendations of our RF review committee (2). Files and reference documents are compiled in Section IV.

High density plasma gun generates plasmas at 190 kilometers per second

Science.gov (United States)

Espy, P. N.

1971-01-01

Gun has thin metal foil disc which positions or localizes gas to be ionized during electrical discharge cycle, overcoming major limiting factor in obtaining such plasmas. Expanding plasma front travels at 190 km/sec, compared to plasmas of 50 to 60 km/sec previously achieved.

Feasibility and acceptability of interventions to delay gun access in VA mental health settings.

Science.gov (United States)

Walters, Heather; Kulkarni, Madhur; Forman, Jane; Roeder, Kathryn; Travis, Jamie; Valenstein, Marcia

2012-01-01

The majority of VA patient suicides are completed with firearms. Interventions that delay patients' gun access during high-risk periods may reduce suicide, but may not be acceptable to VA stakeholders or may be challenging to implement. Using qualitative methods, stakeholders' perceptions about gun safety and interventions to delay gun access during high-risk periods were explored. Ten focus groups and four individual interviews were conducted with key stakeholders, including VA mental health patients, mental health clinicians, family members and VA facility leaders (N=60). Transcripts were consensus-coded by two independent coders, and structured summaries were developed and reviewed using a consensus process. All stakeholder groups indicated that VA health system providers had a role in increasing patient safety and emphasized the need for providers to address gun access with their at-risk patients. However, VA mental health patients and clinicians reported limited discussion regarding gun access in VA mental health settings during routine care. Most, although not all, patients and clinicians indicated that routine screening for gun access was acceptable, with several noting that it was more acceptable for mental health patients. Most participants suggested that family and friends be involved in reducing gun access, but expressed concerns about potential family member safety. Participants generally found distribution of trigger locks acceptable, but were skeptical about its effectiveness. Involving Veteran Service Organizations or other individuals in temporarily holding guns during high-risk periods was acceptable to many participants but only with numerous caveats. Patients, clinicians and family members consider the VA health system to have a legitimate role in addressing gun safety. Several measures to delay gun access during high-risk periods for suicide were seen as acceptable and feasible if implemented thoughtfully. Published by Elsevier Inc.

Gun Violence Following Inpatient Psychiatric Treatment: Offense Characteristics, Sources of Guns, and Number of Victims.

Science.gov (United States)

Kivisto, Aaron J

2017-10-01

This study presents data on the relative contribution to gun violence by people with a history of inpatient psychiatric treatment and on federal efforts to deter presumptively dangerous persons from obtaining firearms, information useful for analyzing the potential public health benefits of gun policies targeting people with serious mental illness. The study also estimates the reduction in gun violence victims that would be expected if individuals with a previous psychiatric hospitalization were prohibited from purchasing firearms. Data from 838 violent gun offenders from a nationally representative sample of state prison inmates were analyzed. Those with and without a history of psychiatric hospitalization were compared on a range of offense characteristics, including relationship to the victim, number of victims, location of the offense, and source of firearms. Inmates with a history of hospitalization constituted 12% of all violent gun offenders and accounted for 13% of the sample's victims. They were less likely than those without a previous hospitalization to victimize strangers (odds ratio=.52) and were no more likely to commit gun violence in public or to have multiple victims. Among those with previous hospitalizations, 78% obtained guns from sources not subject to federal background checks. Of the total 1,041 victims of gun violence, only 3% were victimized by participants with a history of hospitalization who obtained guns from currently regulated sources. Prohibiting all individuals with a history of psychiatric hospitalization from purchasing firearms, absent expanded background checks, was estimated to reduce the number of gun violence victims by only 3%.

Unbalanced field RF electron gun

Science.gov (United States)

Hofler, Alicia

2013-11-12

A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

OpenAIRE

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

2013-01-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spe...

Design and experimental results of a new electron gun using a magnetic multipole plasma generator

International Nuclear Information System (INIS)

Tanaka, S.; Yokoyama, K.; Akiba, M.; Araki, M.; Dairaku, M.; Inoue, T.; Mizuno, M.; Okumura, Y.; Ohara, Y.; Seki, M.; Watanabe, K.

1991-01-01

A new electron gun utilizing a magnetic multipole plasma generator was designed and fabricated as the heat source of the high heat flux test facility, called JEBIS (JAERI electron beam irradiation stand). By changing the acceleration grids, this electron gun is able to produce a pencil to a sheetlike electron beams up to 4 A at 100 keV for 1 ms to continuous mode. In this electron gun, magnetic lens system is not adopted to focus the electron beam, but the space charge neutralization effect by the beam plasma produced downstream of the electron gun is utilized to prevent the blow-up of the electron beam. In addition, high permeability metal is embedded in the first and the second grids to magnetically shield the earth field and the stray field from the beam bending magnet. It was experimentally demonstrated that wide range of heat flux from 0.2 MW/m 2 to over 2000 MW/m 2 can be realized at the test sample position about 1.7 m downstream of the electron gun

From gun politics to self-defense politics: a feminist critique of the great gun debate.

Science.gov (United States)

Carlson, Jennifer D

2014-03-01

This article calls attention to a problematic binary produced by public debates surrounding gun rights and gun control-namely, that women must choose armed self-protection or no self-protection at all. I argue that both anti- and pro-gun discourses, drawing on and reproducing race and class privileges, use assumptions about women's physical inferiority to further their agendas. I highlight how both sides have used guns as the proxy for self-defense and conclude by calling for a shift in public discourse to focus on the broader question of the right to self-defense rather than the narrower question of gun rights.

A high-brightness thermionic microwave electron gun

Energy Technology Data Exchange (ETDEWEB)

Borland, Michael [Stanford Univ., CA (United States)

1991-02-01

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun`s performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ``State-of-the-art`` microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of < 10 π • m_ec • μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10⁹e^- per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically < 30 π • m_e • μm.

Hard-driven rail-gun tests

International Nuclear Information System (INIS)

Peterson, D.R.; Adams, D.F.; Cummings, C.E.; Fowler, C.M.; Kerrisk, J.F.; Marsh, S.P.; Parker, J.V.

1983-01-01

A number of prototype rail-gun designs have been tested, powered by explosive magnetic flux compression generators. Peak currents as high as 1.3 MA were delivered. Rail guns with 50-mm-thick Kevlar fiberwound structural shells were able to survive these high currents with minimum mechanical damage and were refired after enlarging the bores 0.2 to 0.4 mm to remove arc damage. In some tests, mechanical damage occurred that was apparently caused by the rebound of the gun after firing. Although the Kevlar shells had more than adequate strength, they appeared to lack sufficient stiffness, allowing excessive deflections. The use of a steel structural shell with a Kevlar sleeve was an improvement. Intrusion into the seams of the rail guns and condensation of material from the plasma armature were observed. Improved sealing of seams is indicated. In some cases, we suspect maldistribution of current within the gun; that is, not all the current delivered to the breech of the gun seemed to reach the plasma armature. Experiments are being designed to quantify the effects discussed. Rail guns of advanced design are being fabricated. An 18-g titanium projectile was accelerated to 2.4 km/s in a 16-mm-round-bore, 0.6-m-long gun, 4-6 g polycarbonate projectiles were accelerated to 3.5 km/s in 13-mm-square-bore, 1.2-m-long rail guns. All tests were conducted at atmospheric pressure

Effect of charge exchange on ion guns and an application to inertial- electrostatic confinement devices

International Nuclear Information System (INIS)

Baxter, D.C.; Stuart, G.W.

1982-01-01

In 1967, R. L. Hirsch [J. Appl. Phys. 38, 4522 (1967)] reported neutron production rates of 10 10 neutrons per second from an electrostatic inertial confinement device. The device consisted of six ion guns injecting deuterium or a mixture of deuterium and tritium ions into an evacuated cathode chamber at 30--150 keV. No previous theoretical model for this experiment has adequately explained the observed neutron fluxes. A new model that includes the effects of charge exchange and ionization in the ion guns is analyzed. This model predicts three main features of the observed neutron flux: Neutron output proportional to gun current, neutron production localized at the center of the evacuated chamber, and neutron production decreasing with increasing neutral background gas density. Previous analysis modelled the ion guns as being monoenergetic. In this study, the ion gun output is modelled as a mixture of ions and fast neutrals with energies ranging from zero to the maximum gun energy. Using this theoretical model, a survey of the possible operating parameters indicates that the device was probably operated at or near the most efficient combined values of voltage and background pressure. Applications of the theory to other devices are discussed

Storm water permitting for oil and gas facilities

International Nuclear Information System (INIS)

de Blanc, P.C.

1991-01-01

After several false starts, the US Environmental Protection Agency (EPA) published new federal storm water regulations in the November 16, 1990 Federal Register. These regulations identify facilities which must apply for a storm water permit and detail permit application requirements. The regulations appear at 40 CFR 122 Subpart B and became effective December 17, 1990. An outline of these regulations and their applicability to oil and gas facilities is presented. They are: facilities which require a storm water permit; types of storm water permits; permit application deadlines; permit application forms; facilities with existing storm water permits; storm water permit application data requirements; storm water sampling and analysis requirements; and EPA contacts for additional information

A high-brightness thermionic microwave electron gun

International Nuclear Information System (INIS)

Borland, M.

1991-02-01

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun's performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ''State-of-the-art'' microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of e c · μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10 9 e - per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically e · μm

Risk management technique for liquefied natural gas facilities

Science.gov (United States)

Fedor, O. H.; Parsons, W. N.

1975-01-01

Checklists have been compiled for planning, design, construction, startup and debugging, and operation of liquefied natural gas facilities. Lists include references to pertinent safety regulations. Methods described are applicable to handling of other hazardous materials.

Racism, Gun Ownership and Gun Control: Biased Attitudes in US Whites May Influence Policy Decisions

OpenAIRE

O?Brien, Kerry; Forrest, Walter; Lynott, Dermot; Daly, Michael

2013-01-01

OBJECTIVE: Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. METHOD: The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US wh...

Design and modelling of a 5 MeV radio frequency electron gun

International Nuclear Information System (INIS)

Batchelor, K.; Sheehan, J.; Woodle, M.

1988-01-01

The Accelerator Test Facility (ATF) at Brookhaven National Laboratory is a linac-laser complex for research into laser acceleration and for the generation of coherent radiation from electron beams. In order to achieve the design 50 MeV output emittance (γσ/sub x/σ/sub x/') of less than 3 /times/ 10/sup /minus/5/ m rad a high brightness electron gun is required. This paper describes computations and measurements made on a full scale brass model of a 1-1/2 cell, π-mode, resonant, disc loaded, radiofrequency gun structure which has been designed for this purpose. 7 refs., 9 figs., 6 tabs

Helium turbomachinery operating experience from gas turbine power plants and test facilities

International Nuclear Information System (INIS)

McDonald, Colin F.

2012-01-01

The closed-cycle gas turbine, pioneered and deployed in Europe, is not well known in the USA. Since nuclear power plant studies currently being conducted in several countries involve the coupling of a high temperature gas-cooled nuclear reactor with a helium closed-cycle gas turbine power conversion system, the experience gained from operated helium turbomachinery is the focus of this paper. A study done as early as 1945 foresaw the use of a helium closed-cycle gas turbine coupled with a high temperature gas-cooled nuclear reactor, and some two decades later this was investigated but not implemented because of lack of technology readiness. However, the first practical use of helium as a gas turbine working fluid was recognized for cryogenic processes, and the first two small fossil-fired helium gas turbines to operate were in the USA for air liquefaction and nitrogen production facilities. In the 1970's a larger helium gas turbine plant and helium test facilities were built and operated in Germany to establish technology bases for a projected future high efficiency large nuclear gas turbine power plant concept. This review paper covers the experience gained, and the lessons learned from the operation of helium gas turbine plants and related test facilities, and puts these into perspective since over three decades have passed since they were deployed. An understanding of the many unexpected events encountered, and how the problems, some of them serious, were resolved is important to avoid them being replicated in future helium turbomachines. The valuable lessons learned in the past, in many cases the hard way, particularly from the operation in Germany of the Oberhausen II 50 MWe helium gas turbine plant, and the technical know-how gained from the formidable HHV helium turbine test facility, are viewed as being germane in the context of current helium turbomachine design work being done for future high efficiency nuclear gas turbine plant concepts. - Highlights: �

CID thermionic gun system

International Nuclear Information System (INIS)

Koontz, R.F.

1981-10-01

A new high-current thermionic gun has been installed on the CID injector at SLAC and brought into operation. The gun and pulser system generate three nanosecond pulses of about six amps peak which, when bunched in the subharmonic buncher system, produce in excess of 10 11 electrons in a single S-band accelerated bunch. Preliminary operation of the gun is described, and details of the avalanche cathode drive pulser are presented

CID thermionic gun system

International Nuclear Information System (INIS)

Koontz, R.F.

1982-01-01

A new high-current thermionic gun has been installed on the CID injector at SLAC and brought into operation. The gun and pulser system generate three nanosecond pulses of about six amps peak which, when bunched in the subharmonic buncher system, produce in excess of 10 11 electrons in a single S-band accelerated bunch. Preliminary operation of the gun is described, and details of the avalanche cathode drive pulser are presented

Future use of BI-GAS facility. Final report, Part II. [Other possible uses

Energy Technology Data Exchange (ETDEWEB)

1981-09-01

The 120 tpd BI-GAS pilot plant, intended to produce SNG at high pressure, was completed in 1976. For the next three and a half years, the operator, Stearns-Roger Inc., was engaged in operating the plant while overcoming a series of mechanical problems that have prevented the plant from running at design capacity and pressure. Since July 1980, these problems have apparently been corrected and considerable progress was made. In late 1979, the Yates Congressional Committee directed DOE to investigate the possibility of establishing an entrained-bed gasifier test facility at the site. In January 1981, the DOE established a study group composed of DOE and UOP/SDC personnel to determine how best to use the BI-GAS facility. The group considered four possibilities: Continue operation of the facility in accordance with the technical program plan developed by DOE and Stearns-Roger; modify the plant into an entrained-bed facility for testing components and processes; mothball the facility, or dismantle the facility. The group took the view that modifying the plant into a test facility would increase substantially the amount of engineering data available to the designers of commercial gasification plants. Since it appears that syngas plants will be of commercial interest sooner than SNG plants will, it was decided that the facility should test syngas production components and processes at high pressure. Consequently, it was recommended that: Operation of the plant be continued, both to collect data and to prove the BI-GAS process, as long as the schedule of the technical program plan is met; Begin at once to prepare a detailed design for modifying the BI-GAS plant to a high-pressure, entrained flow syngas test facility; and Implement the modification plan as soon as the BI-GAS process is proven or it becomes apparent that progress is unsatisfactory.

X-Band RF Gun Development

International Nuclear Information System (INIS)

Vlieks, A.E.

2012-01-01

In support of the MEGa-ray program at LLNL and the High Gradient research program at SLAC, a new X-band multi-cell RF gun is being developed. This gun, similar to earlier guns developed at SLAC for Compton X-ray source program, will be a standing wave structure made of 5.5 cells operating in the pi mode with copper cathode. This gun was designed following criteria used to build SLAC X-band high gradient accelerating structures. It is anticipated that this gun will operate with surface electric fields on the cathode of 200 MeV/m with low breakdown rate. RF will be coupled into the structure through a final cell with symmetric duel feeds and with a shape optimized to minimize quadrupole field components. In addition, geometry changes to the original gun, operated with Compton X-ray source, will include a wider RF mode separation, reduced surface electric and magnetic fields.

Fatal chlorine gas exposure at a metal recycling facility: Case report.

Science.gov (United States)

Harvey, Robert R; Boylstein, Randy; McCullough, Joel; Shumate, Alice; Yeoman, Kristin; Bailey, Rachel L; Cummings, Kristin J

2018-06-01

At least four workers at a metal recycling facility were hospitalized and one died after exposure to chlorine gas when it was accidentally released from an intact, closed-valved cylinder being processed for scrap metal. This unintentional chlorine gas release marks at least the third such incident at a metal recycling facility in the United States since 2010. We describe the fatal case of the worker whose clinical course was consistent with acute respiratory distress syndrome (ARDS) following exposure to high concentrations of chlorine gas. This case report emphasizes the potential risk of chlorine gas exposure to metal recycling workers by accepting and processing intact, closed-valved containers. The metal recycling industry should take steps to increase awareness of this established risk to prevent future chlorine gas releases. Additionally, public health practitioners and clinicians should be aware that metal recycling workers are at risk for chlorine gas exposure. © 2018 Wiley Periodicals, Inc.

Preventing gun injuries in children.

Science.gov (United States)

Crossen, Eric J; Lewis, Brenna; Hoffman, Benjamin D

2015-02-01

Firearms are involved in the injury and death of a large number of children each year from both intentional and unintentional causes. Gun ownership in homes with children is common, and pediatricians should incorporate evidence-based means to discuss firearms and protect children from gun-related injuries and violence. Safe storage of guns, including unloaded guns locked and stored separately from ammunition, can decrease risks to children, and effective tools are available that pediatricians can use in clinical settings to help decrease children's access to firearms. Furthermore, several community-based interventions led by pediatricians have effectively reduced firearm-related injury risks to children. Educational programs that focus on children's behavior around guns have not proven effective. © American Academy of Pediatrics, 2015. All rights reserved.

Impact Testing for Materials Science at NASA - MSFC

Science.gov (United States)

Sikapizye, Mitch

2010-01-01

The Impact Testing Facility (ITF) at NASA - Marshall Space Flight Center is host to different types of guns used to study the effects of high velocity impacts. The testing facility has been and continues to be utilized for all NASA missions where impact testing is essential. The Facility has also performed tests for the Department of Defense, other corporations, as well as universities across the nation. Current capabilities provided by Marshall include ballistic guns, light gas guns, exploding wire gun, and the Hydrometeor Impact Gun. A new plasma gun has also been developed which would be able to propel particles at velocities of 20km/s. This report includes some of the guns used for impact testing at NASA Marshall and their capabilities.

Gun violence trends in movies.

Science.gov (United States)

Bushman, Brad J; Jamieson, Patrick E; Weitz, Ilana; Romer, Daniel

2013-12-01

Many scientific studies have shown that the mere presence of guns can increase aggression, an effect dubbed the "weapons effect." The current research examines a potential source of the weapons effect: guns depicted in top-selling films. Trained coders identified the presence of violence in each 5-minute film segment for one-half of the top 30 films since 1950 and the presence of guns in violent segments since 1985, the first full year the PG-13 rating (age 13+) was used. PG-13-rated films are among the top-selling films and are especially attractive to youth. Results found that violence in films has more than doubled since 1950, and gun violence in PG-13-rated films has more than tripled since 1985. When the PG-13 rating was introduced, these films contained about as much gun violence as G (general audiences) and PG (parental guidance suggested for young children) films. Since 2009, PG-13-rated films have contained as much or more violence as R-rated films (age 17+) films. Even if youth do not use guns, these findings suggest that they are exposed to increasing gun violence in top-selling films. By including guns in violent scenes, film producers may be strengthening the weapons effect and providing youth with scripts for using guns. These findings are concerning because many scientific studies have shown that violent films can increase aggression. Violent films are also now easily accessible to youth (e.g., on the Internet and cable). This research suggests that the presence of weapons in films might amplify the effects of violent films on aggression.

Low emittance thermionic electron guns

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1989-01-01

The author discusses self-field effects and external field effects for electron guns. He also discusses designs of electron guns and their uses in electron cooling systems and as an injector for electrostatic free electron lasers. He closes by looking at electron guns for linear accelerators. 20 references, 3 figures

Energy and Technology Review

International Nuclear Information System (INIS)

1986-03-01

An overview is given of research programs at a two-stage light-gas gun facility. Representative gas-gun experiments are described, and the impact of this research on other LLNL programs and on high-pressure physics work in general are discussed. Particular applications reported include: measurement of equations of state for various materials, synthesis and study of novel materials, and studies of high explosives. Specialized diagnostic techniques for gas-gun experiments are reviewed

Energy and Technology Review

Energy Technology Data Exchange (ETDEWEB)

1986-03-01

An overview is given of research programs at a two-stage light-gas gun facility. Representative gas-gun experiments are described, and the impact of this research on other LLNL programs and on high-pressure physics work in general are discussed. Particular applications reported include: measurement of equations of state for various materials, synthesis and study of novel materials, and studies of high explosives. Specialized diagnostic techniques for gas-gun experiments are reviewed. (LEW)

Guns at College.

Science.gov (United States)

Miller, Matthew; Hemenway, David; Wechsler, Henry

1999-01-01

Surveyed undergraduate students nationwide concerning firearm possession. About 3.5% possessed working firearms. Students with guns were more likely to be male, White, or Native American; binge drink; live off-campus; and live with a spouse or significant other. Students with guns were more likely to engage in activities that put themselves and…

Preliminary Langmuir probe results on the CTX gun experiment

International Nuclear Information System (INIS)

Tuszewski, M.

1981-12-01

Preliminary results obtained with a double Langmuir probe in the Compact Toroid experiment facility confirm the existence of a gun plasma of n approx. 5 x 10 14 cm -3 and T approx. 10 eV lasting for approx. 250 to 400 μs, which is consistent with interferometry and Thomson scattering data. The probe current characteristics as a function of voltage suggest non-Maxwellian features of the particles distribution functions

Acoustic absorption of natural gas compression facility enclosures

Energy Technology Data Exchange (ETDEWEB)

Lassen, P.; Wong, G. [Noise Management Ltd., Calgary, AB (Canada)

2009-07-01

Noise sources at gas compressor facilities include the enclosure/building housing a gas engine and compressor, the ventilation openings, doors and windows for the enclosure, the engine air intake and exhaust, and a cooler. Accurate predictions of the noise levels inside the enclosure, the breakout noise from open windows and doors and ventilation, as well as the transmission through the walls, is necessary in order to determine cost effective noise mitigation for the facility. In order to accurately predict the sound breakout from these facilities it is necessary to know the acoustic absorption of the interior of these equipment enclosures. Although the acoustic absorption data of the wall systems may be available, the absorption attributable to the non-enclosure surfaces, the equipment and fittings, is not usually known and is difficult to predict. Since piping, instrumentation and mechanical equipment often take on a typical arrangement, shape, volumetric density and material composition, it is useful to know the typical acoustic absorption attributable to these items. In this study, reverberation time (RT) measurements were taken at 2 decommissioned gas compressor facilities in order to determine the absorption characteristics of the enclosure. The RT was measured according to ASTM C423-02a. The overall absorption coefficient of a compressor enclosure with a solid liner was found to be similar to that of steel decking. Fittings within the enclosure did not increase the high frequency absorption of the enclosure. It was concluded that room modes, structural vibrations, and fittings may serve to increase the effective absorption at frequencies below 630 Hz. Because of the small dimensions of the enclosure, low-frequency response of the room affected the reliability of the data below 160Hz. Structural vibration of the enclosure was investigated, and may considerably influence the noise breakout from the enclosure apart from the interior acoustical considerations. 4

Acoustic absorption of natural gas compression facility enclosures

International Nuclear Information System (INIS)

Lassen, P.; Wong, G.

2009-01-01

Noise sources at gas compressor facilities include the enclosure/building housing a gas engine and compressor, the ventilation openings, doors and windows for the enclosure, the engine air intake and exhaust, and a cooler. Accurate predictions of the noise levels inside the enclosure, the breakout noise from open windows and doors and ventilation, as well as the transmission through the walls, is necessary in order to determine cost effective noise mitigation for the facility. In order to accurately predict the sound breakout from these facilities it is necessary to know the acoustic absorption of the interior of these equipment enclosures. Although the acoustic absorption data of the wall systems may be available, the absorption attributable to the non-enclosure surfaces, the equipment and fittings, is not usually known and is difficult to predict. Since piping, instrumentation and mechanical equipment often take on a typical arrangement, shape, volumetric density and material composition, it is useful to know the typical acoustic absorption attributable to these items. In this study, reverberation time (RT) measurements were taken at 2 decommissioned gas compressor facilities in order to determine the absorption characteristics of the enclosure. The RT was measured according to ASTM C423-02a. The overall absorption coefficient of a compressor enclosure with a solid liner was found to be similar to that of steel decking. Fittings within the enclosure did not increase the high frequency absorption of the enclosure. It was concluded that room modes, structural vibrations, and fittings may serve to increase the effective absorption at frequencies below 630 Hz. Because of the small dimensions of the enclosure, low-frequency response of the room affected the reliability of the data below 160Hz. Structural vibration of the enclosure was investigated, and may considerably influence the noise breakout from the enclosure apart from the interior acoustical considerations. 4

Relationship between licensing, registration, and other gun sales laws and the source state of crime guns.

Science.gov (United States)

Webster, D W; Vernick, J S; Hepburn, L M

2001-09-01

To determine the association between licensing and registration of firearm sales and an indicator of gun availability to criminals. Tracing data on all crime guns recovered in 25 cities in the United States were used to estimate the relationship between state gun law categories and the proportion of crime guns first sold by in-state gun dealers. In cities located in states with both mandatory registration and licensing systems (five cities), a mean of 33.7% of crime guns were first sold by in-state gun dealers, compared with 72.7% in cities that had either registration or licensing but not both (seven cities), and 84.2% in cities without registration or licensing (13 cites). Little of the difference between cities with both licensing and registration and cities with neither licensing nor registration was explained by potential confounders. The share of the population near a city that resides in a neighboring state without licensing or registration laws was negatively associated with the outcome. States with registration and licensing systems appear to do a better job than other states of keeping guns initially sold within the state from being recovered in crimes. Proximity to states without these laws, however, may limit their impact.

State-of-the-Art Electron Guns and Injector Designs for Energy Recovery Linacs (ERL)

CERN Document Server

Todd, Alan; Ben-Zvi, Ilan; Benson, Stephen V; Blüm, Hans; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Campisi, Isidoro E; Chang, Xiangyun; Christina, Vincent; Cole, Michael; Colestock, Patrick L; Daly, Edward; Douglas, David; Dylla, Fred H; Falletta, Michael; Hahn, Harald; Hernandez-Garcia, Carlos; Hogan, John; Holmes, Douglas; Janssen, Dietmar; Kayran, Dmitry; Kelley, John P; Kewisch, Jorg; Kneisel, Peter; Kurennoy, Sergey; Lewellen, John W; Litvinenko, Vladimir N; Mammosser, John; McIntyre, Gary; Neil, George R; Nguyen, Dinh C; Nicoletti, Tony; Peterson, Ed; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Reass, William; Rees, Daniel; Rimmer, Robert; Rode, Claus; Russell, Steven; Scaduto, Joseph; Schrage, Dale L; Schultheiss, Tom; Sekutowicz, Jacek; Siggins, Tim; Warren Funk, L; Whitlach, Timothy; Wiseman, Mark; Wong, Robert; Wood, Richard L; Wu, Kuo-Chen; Young, Lloyd M; Zaltsman, Alex; Zhao, Yongxiang

2005-01-01

A key technology issue of ERL devices for high-power free-electron laser (FEL) and 4th generation light sources is the demonstration of reliable, high-brightness, high-power injector operation. Ongoing programs that target up to 1 Ampere injector performance at emittance values consistent with the requirements of these applications are described. We consider that there are three possible approaches that could deliver the required performance. The first is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. Such a 750 MHz device is being integrated and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility beginning in 2007. The second approach is a high-current normal-conducting RF photoinjector. A 700 MHz gun will undergo thermal test in 2006 at the Los Alamos National Laboratory, which, if successful, when equipped with a suitable cathode, would be capable of 1 Ampere operation. The last option is an SRF gun. A half-cell 703 MHz SRF gun capable of delivering 1.0...

RF guns: a review

International Nuclear Information System (INIS)

Travier, C.

1990-06-01

Free Electron Lasers and future linear colliders require very bright electron beams. Conventional injectors made of DC guns and RF bunchers have intrinsic limitations. The recently proposed RF guns have already proven their capability to produce bright beams. The necessary effort to improve further these performances and to gain reliability is now undertaken by many laboratories. More than twenty RF gun projects both thermionic and laser-driven are reviewed. Their specific characteristics are outlined and their nominal performances are given

THE IMPROVEMENT AND APPLICATION OF EI-GUN (ELECTRICAL INSEMINATION GUN FOR ARTIFICIAL INSEMINATION (AI USING GOAT FRESH SEMEN

Directory of Open Access Journals (Sweden)

Mirsa Ita Dewi

2017-03-01

Full Text Available Electrical Insemination Gun (EI-GUN was a tool for Artificial Insemination (AI using fresh semen with an electric control system. The research objective was to produced EI-GUN for AI using fresh semen on small ruminants (goat. The research was conducted from March to June 2015. The process of EI-GUN creation implemented in Design and Prototype Laboratory and Aero Modeling Research Laboratory at Engineering Faculty, University of Brawijaya (UB. Testing tools EI-GUN on goat was conducted in the Sumber Sekar Laboratory, Animal Husbandry Faculty, UB.  The methods of research were literature study, tool specification determination, designing EI-GUN, running test, semen evaluation passed EI-GUN and application on Goat. EI-GUN has seven important parts, which supports each other in this operating system. Those parts consist of stylet, servo, system controlled, insemination pump, connecting rod, battery, and holder. EI-GUN work system sucked the semen into insemination pump as much as 5 ml, and release the semen 0.25 ml appropriate standard of AI. It was applicable for 20 times AI. The results showed that the cell motility of spermatozoa ≥ 70% were still in ranging of Indonesian National Standard (SNI.   Keywords: artificial insemination, EI-GUN, fresh semen.

Electric gun: a new method for generating shock pressures in excess of 1 TPa

International Nuclear Information System (INIS)

Steinberg, D.; Chau, H.; Dittbenner, G.; Weingart, R.

1978-01-01

By combining the electrically-driven, flying-plate, high-explosive initiator with well-known gas-gun technology, a novel method of generating and measuring shock pressures greater than 1 TPa has been developed. Called the electric gun, this system is competitive with laser or nuclear-driven, shock-wave, equation-of-state experiments in the 1 to 5 TPa range. Compared to those other methods, it has the advantage of simplicity, high precision, and low cost. In addition, its small size and low total energy allow it to be easily contained for experiments with toxic materials

Understanding and Predicting Gun Barrel Erosion

National Research Council Canada - National Science Library

Johnston, Ian A

2005-01-01

The Australian Defence Force will soon have to contend with gun barrel erosion issues arising from the use of new low-vulnerability gun propellants, the acquisition of new ammunition and gun systems...

Preliminary exploitation of industrial facility for flue gas treatment

International Nuclear Information System (INIS)

Chmielewski, A.G.; Zimek, Z.; Iller, E.; Tyminski, B.; Licki, J.

2001-01-01

Full text: High emission of SO 2 and NO x in the process of fossil fuel combustion creates a major world environmental problem. Poland which uses for energy production mainly pit and brown coal produces these pollutants as well. The certain amount of SO 2 and slightly less NO x pollutants is introduced into the atmosphere. 1/2 of SO 2 and 1/3 NO x pollution is contributed by heat and electricity generating boilers. The biggest sources of pollution are located in south west side of Poland and are connected with industrial centers but over 45% of the total 802 and 69% of NO x pollutants distributed over polish territory come from external sources. The laboratory facility for flue gas treatment radiation technology was organized in Institute of Nuclear Chemistry and Technology at Warsaw at the end of 80s. Soon after the pilot plant for flue gas treatment with electron beam has been installed at Power Plant Kaweczyn near Warsaw. The flow capacity trough those installations was respectively 400 and 20000 Nm /h. Three new elements have been introduced to the construction of the radiation chamber in Polish pilot installation. Those are: cascade double stage irradiation, longitudinal irradiation, (beam scanned along the chamber axis) and the air blow under the chamber window with the purpose to create air curtain separating the window from the flue gases causing corrosion. Three different system for filtration aid has been constructed and tested: bag filter, gravel bead filter and electrostatic precipitator. The pilot plant installation was used to establish the optimal parameters of industrial facility: optimizing of the process parameters leading to reduction of energy with high efficiency of SO 2 and NO x removal; selecting and testing filter devices and filtration process; developing of the monitoring and control systems at industrial plant for flue gas cleaning, preparation of the design for industrial scale facility. The positive results of the tests performed on

Characterization of a medium-sized washer-gun for an axisymmetric mirror

Science.gov (United States)

Yi, Hongshen; Liu, Ming; Shi, Peiyun; Yang, Zhida; Zhu, Guanghui; Lu, Quanming; Sun, Xuan

2018-04-01

A new medium-sized washer gun is developed for a plasma start-up in a fully axisymmetric mirror. The gun is positioned at the east end of the Keda Mirror with AXisymmetricity facility and operated in the pulsed mode with an arc discharging time of 1.2 ms and a typical arc current of 8.5 kA with 1.5 kV discharge voltage. To optimize the operation, a systematic scan of the neutral pressure, the arc voltage, the bias voltage on a mesh grid 6 cm in front of the gun and an end electrode located on the west end of mirror, and the mirror ratio was performed. The streaming plasma was measured with triple probes in the three mirror cells and a diamagnetic loop in the central cell. Floating potential measurements suggest that the plasma could be divided into streaming and mirror-confined plasmas. The floating potential for the streaming plasma is negative, with an electric field pointing inwards. The mirror-confined plasma has a typical lifetime of 0.5 ms.

Magnetic Ignition of Pulsed Gas Discharges in Air of Low Pressure in a Coaxial Plasma Gun

Science.gov (United States)

Thom, Karlheinz; Norwood, Joseph, Jr.

1961-01-01

The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.

Automatic targeting of plasma spray gun

Science.gov (United States)

Abbatiello, Leonard A.; Neal, Richard E.

1978-01-01

A means for monitoring the material portion in the flame of a plasma spray gun during spraying operations is provided. A collimated detector, sensitive to certain wavelengths of light emission, is used to locate the centroid of the material with each pass of the gun. The response from the detector is then relayed to the gun controller to be used to automatically realign the gun.

Automatic targeting of plasma spray gun

International Nuclear Information System (INIS)

Abbatiello, L.A.; Neal, R.E.

1978-01-01

A means for monitoring the material portion in the flame of a plasma spray gun during spraying operations is described. A collimated detector, sensitive to certain wavelengths of light emission, is used to locate the centroid of the material with each pass of the gun. The response from the detector is then relayed to the gun controller to be used to automatically realign the gun

Electron gun for technological linear accelerator

International Nuclear Information System (INIS)

Khodak, I.V.; Kushnir, V.A.; Mirochenko, V.V.; Stepin, D.L.; Zavada, L.M.

2000-01-01

The work is purposed to the design of diode electron gun for powerful technologic electron linac and to experimental investigations of the beam parameters at the gun exit.The gun feature is the quick cathode replacement.This is very impotent for operating of the accelerator.The gun optics and beam parameters were calculated using the EGUN code.Beam parameters were investigated as at the special test stand so as component of the linac injector.The gun produces the beam current of 2 A at the anode voltage 25 kV.Measured beam parameters correspond to calculated results

Are "goods for guns" good for the community? An update of a community gun buyback program.

Science.gov (United States)

Green, Jonathan; Damle, Rachelle N; Kasper, Rebecca E; Violano, Pina; Manno, Mariann; Nazarey, Pradeep P; Aidlen, Jeremy T; Hirsh, Michael P

2017-08-01

Gun violence remains a leading cause of death in the United States. Community gun buyback programs provide an opportunity to dispose of extraneous firearms. The purpose of this study was to understand the demographics, motivation, child access to firearms, and household mental illness of buyback participants in hopes of improving the program's effectiveness. A 2015 Injury Free Coalition for Kids gun buyback program which collaborated with local police departments was studied. We administered a 23-item questionnaire survey to gun buyback participants assessing demographic characteristics, motivation for relinquishing firearms, child firearm accessibility, and mental illness/domestic violence history. A total of 186 individuals from Central/Western Massachusetts turned in 339 weapons. Participants received between US $25 and US $75 in gift cards dependent on what type of gun was turned in, with an average cost of $41/gun. A total of 109 (59%) participants completed the survey. Respondents were mostly white (99%), men (90%) and first-time participants in the program (85.2%). Among survey respondents, 54% turned in firearms "for safety reasons." Respondents reported no longer needing/wanting their weapons (47%) and approximately one in eight participants were concerned the firearm(s) were accessible to children. Most respondents (87%) felt the program encouraged neighborhood awareness of firearm safety. Three of every five participants reported that guns still remained in their homes; additionally, 21% where children could potentially access them and 14% with a history of mental illness/suicide/domestic violence in the home. Gun buybacks can provide a low-cost means of removing unwanted firearms from the community. Most participants felt their homes were safer after turning in the firearm(s). In homes still possessing guns, emphasis on secure gun storage should continue, increasing the safety of children and families. The results of this survey also provided new

The ALS Gun Electronics system

International Nuclear Information System (INIS)

Lo, C.C.

1993-05-01

The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

The ALS gun electronics system

International Nuclear Information System (INIS)

Lo, C.C.

1993-01-01

The ALS Gun Electronics system has been designed to accommodate the gun with a custom made socket and a high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

A coaxial plasma gun with a controllable streaming velocity in the range of 2-90 km secsup(-1)

International Nuclear Information System (INIS)

Venkataramani, N.; Mattoo, S.K.

1981-01-01

A coaxial plasma gun capable of producing a plasma stream of velocity ranging between 2 and 90 km secsup(-1) is described. The velocity of the stream is controlled by a variable (0.2-25 Ω) NaCl salt solution resistor in the discharge path of the energy storage connected across the gun. The resistor dissipates an energy of 200 J in the gun discharge current pulse period of 25 μ sec and the consequent heating and dissociation of the electrolyte are insignificant. The electron density of the plasma stream ranges between 10 18 and 10 19 msup(-3) and the temperature is approximately 10 eV. The total number of ions per plasma pulse is approximately 10 18 . The energy transfer efficiency of the gun is approximately 10%. The low transfer efficiency is explained in terms of the experimental requirements and the performance of the valve which admits gas into the gun region. For evaluation of the performance of the gun, several diagnostics have been deployed. A specially designed high voltage capacitor probe is described. (author)

First operation of cesium telluride photocathodes in the TTF injector RF gun

CERN Document Server

Sertore, D; Flöttmann, K; Stephan, F; Zapfe, K; Michelato, P

2000-01-01

During the run 1998/1999 a new injector based on a laser-driven RF gun was brought in operation at the TESLA Test Facility (TTF) linac at DESY, in order to produce the beam structure and quality required either by TeV collider and SASE FEL experiments. High quantum efficiency cesium telluride photocathodes, prepared at Milano and transferred to DESY, have been successfully operated in the RF gun. A bunch charge of 50 nC, only limited by space charge effects, was achieved. The photocathodes have shown an operative lifetime of several months. A new cathode surface finishing has showed a promising decrease of the photocathode dark current. Measurements of dark current, quantum efficiency and lifetime are reported.

Dynamic response of single crystalline copper subjected to quasi-isentropic, gas-gun driven loading

International Nuclear Information System (INIS)

Jarmakani, H.; McNaney, J.M.; Kad, B.; Orlikowski, D.; Nguyen, J.H.; Meyers, M.A.

2007-01-01

A transmission electron microscopy study of quasi-isentropic gas-gun loading (peak pressures between 18 and 52 GPa) of [0 0 1] monocrystalline copper was carried out. The defect substructures at these different pressures were analyzed. Current experimental evidence suggests a deformation substructure that transitions from slip to twinning, where twinning occurs at the higher pressures (∼52 GPa), and heavily dislocated laths and dislocation cells take place at the intermediate and lower pressures. Evidence of stacking faults at the intermediate pressures was also found. Dislocation cell sizes decreased with increasing pressure and increased with distance away from the surface of impact. The results from the quasi-isentropic experiments are compared with those for flyer-plate and laser shock experiments reported in the literature. The Preston-Tonks-Wallace constitutive description is used to model both quasi-isentropic and shock compression experiments and predict the pressure at which the slip-twinning transition occurs in both cases. The model predicts a higher twinning transition pressure for isentropic than for shock experiments, and that twinning should not take place in the quasi-isentropic compression experiments given the loading paths investigated

Glue Guns: Aiming for Safety

Science.gov (United States)

Roy, Ken

2010-01-01

While glue guns are very useful, there are safety issues. Regardless of the temperature setting, glue guns can burn skin. The teacher should demonstrate and supervise the use of glue guns and have a plan should a student get burned. There should be an initial first aid protocol in place, followed by a visit to the school nurse. An accident report…

Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

Energy Technology Data Exchange (ETDEWEB)

Kelly, K.; Melendez, M.; Gonzales, J.; Lynch, L.; Boale, B.; Kohout, J.

2017-09-28

To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. This handbook covers the primary elements that must be considered when developing a CNG vehicle maintenance facility design that will protect against the ignition of natural gas releases. It also discusses specific protocols and training needed to ensure safety.

"Is there a gun in the home?" Assessing the risks of gun ownership in older adults.

Science.gov (United States)

Pinholt, Ellen M; Mitchell, Joshua D; Butler, Jane H; Kumar, Harjinder

2014-06-01

An important ethical and safety concern that geriatricians, primary care providers, and home health professionals need to address is gun ownership by elderly adults. Those aged 65 and older now have the highest rate of gun ownership in America, and they also have a high prevalence of depression and suicide. Dementia can add additional layers of risk. Even older gun owners who are otherwise intellectually intact may benefit from information about gun safety with the increasing numbers of children being cared for by grandparents. Health professionals should ask patients, "Is there a gun in the home?" in the clinic and during home visits. Healthcare professionals must have knowledge and skills to address safe gun ownership in elderly adults. The 5 L's (Locked, Loaded, Little children, feeling Low, Learned owner) will assist professionals in addressing all aspects of safe ownership. © 2014, Copyright the Authors Journal compilation © 2014, The American Geriatrics Society.

Gun buyback programs: a venue to eliminate unwanted guns in the community.

Science.gov (United States)

Violano, Pina; Driscoll, Cassandra; Chaudhary, Neil K; Schuster, Kevin M; Davis, Kimberly A; Borer, Esther; Winters, Jane K; Hirsh, Michael P

2014-09-01

The United States has a high rate of death due to firearms, and gun buyback programs may mitigate these high death rates. Understanding the demographics, motivation, and geographic region of participants may improve program efficacy. Three Injury Free Coalition for Kids gun buyback programs, in collaboration with the local police, were studied: Phoenix, Arizona; Worcester, Massachusetts; and New Haven, Connecticut. Participants were defined as those who relinquished a firearm. A self-administered, anonymous, paper survey elicited information from participants regarding demographic data, formal training on the use of the firearm, how the firearm was acquired, potential child access, knowledge of others injured by a firearm, whether the firearm was stored unlocked, factors motivating the surrender of the firearm, and other factors. Survey results were entered into a composite database and analyzed for differences in location, race, sex, and other factors. Participants (n = 301) were predominantly male (73.5%), white (80.9%), and older than 55 years (59.0%). They lived an average of 19.0 miles from the event by zip codes and had an average median household income of $65,731. More than half (54.5%) did not purchase the firearm, acquiring it through inheritance, gift, or random find. Most (74.8%) had previous firearms training and were relinquishing for safety reasons (68.3%). Those relinquishing firearms for safety reasons were less likely to have purchased the firearm (odds ratio [OR], 2.46, p gun lock (OR, 0.15; p gun-wielding criminal acts were burglarized from the home of legal gun owners that had failed to secure them properly. The gun buyback program is solely one prong of a multipronged approach in reducing firearm-based interpersonal violence. Additional research is necessary to determine effective methods to target individuals who would have the greatest impact on gun violence if they relinquished their weapons. Through the forging of relationships and

Sodium and cover gas chemistry in the high temperature sodium facility

International Nuclear Information System (INIS)

McCown, J.J.; Duncan, H.C.

1976-01-01

The equipment and procedures used in following sodium and cover gas chemistry changes in the High Temperature Sodium Facility are presented. The methods of analysis and results obtained are given. Impurity trends which have been measured during the facility operations are discussed

The tariffs of use of liquefied natural gas transportation networks and facilities

International Nuclear Information System (INIS)

2005-01-01

The new tariff proposals for the use of natural gas transportation networks were transmitted to the French Ministry of economy, finances and industry on October 27, 2004 by the commission of energy regulation. These proposals have been adopted and are the object of three legislative texts: the decree no. 2005-607 from May 27 2005 relative to the tariffing rules, the by-law from May 27, 2005 relative to the definition of balancing areas, and the advice from May 27, 2005 relative to the tariffs of use of natural gas transportation networks. In application of article 7 of the law from January 3, 2003, the implementation of the first tariffs of use of natural gas transportation networks and of liquefied natural gas (LNG) facilities is defined in the decree no. 2004-994 from September 21, 2004. On the main transportation network, the tariffing is of 'input-output' type and does not depend on the distance, while at the regional network scale, the tariffing is linked with the distance. The tariff of use of LNG facilities is the sum of 4 terms: a fixed term applied to each batch unloaded at the methane terminal, a term proportional to the unloaded LNG quantities, a term depending on the duration of use of LNG storage facilities and a term covering the gas consumptions of LNG facilities. This document gathers these different legislative texts with their appendixes. (J.S.)

Application of electron beam equipment based on a plasma cathode gun in additive technology

Science.gov (United States)

Galchenko, N. K.; Kolesnikova, K. A.; Semenov, G. V.; Rau, A. G.; Raskoshniy, S. Y.; Bezzubko, A. V.; Dampilon, B. V.; Sorokova, S. N.

2016-11-01

The paper discusses the application of electron beam equipment based on a plasma cathode gun for three-dimensional surface modification of metals and alloys. The effect of substrate surface preparation on the adhesion strength of gas thermal coatings has been investigated.

Instantaneous current and field structure of a gun-driven spheromak for two gun polarities

International Nuclear Information System (INIS)

Woodruff, S; Nagata, M

2002-01-01

The instantaneous plasma structure of the SPHEX spheromak is determined here by numerically processing data from insertable Rogowski and magnetic field probes. Data is presented and compared for two modes of gun operation: with the central electrode biased positively and negatively. It is found that while the mean-, or even instantaneous-, field structure would give the impression of a roughly axisymmetric spheromak, the instantaneous current structure does not. Hundred per cent variations in J measured at the magnetic axis can be explained by the rotation of a current filament that has a width equal to half of the radius of the flux-conserving first wall. In positive gun operation, current leaves the filament in the confinement region leading to high wall current there. In negative gun operation, wall current remains low as all injected current returns to the gun through the plasma. The plasma, in either instance, is strongly asymmetric. We discuss evidence for the existence of the current filament in other gun-driven spheromaks and coaxial plasma thrusters

77 FR 37834 - Revocation of Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns...

Science.gov (United States)

2012-06-25

... Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns Not Intended for Use With Caps AGENCY: Consumer Product Safety Commission. ACTION: Notice of proposed rulemaking. SUMMARY... compliance than our existing regulations pertaining to caps intended for use with toy guns and toy guns not...

Theoretical investigation of a travelling-wave rf gun

International Nuclear Information System (INIS)

Gao, J.

1991-12-01

A travelling-wave type rf gun (TW gun) is investigated theoretically. Analytical formulae concerning energy gain, energy spread, and transverse emittance are derived. After showing the corresponding formulae for the standing-wave rf gun (SW gun), comparisons are made between the two types of rf gun. Finally, some numerical results are calculated to demonstrate further the behaviours of the TW gun, and to compare with those from analytical formulae. (author) 11 refs.; 27 figs

One nanosecond pulsed electron gun systems

International Nuclear Information System (INIS)

Koontz, R.F.

1979-02-01

At SLAC there has been a continuous need for the injection of very short bunches of electrons into the accelerator. Several time-of-flight experiments have used bursts of short pulses during a normal 1.6 micro-second rf acceleration period. Single bunch beam loading experiments made use of a short pulse injection system which included high power transverse beam chopping equipment. Until the equipment described in this paper came on line, the basic grid-controlled gun pulse was limited to a rise time of 7 nanoseconds and a pulse width of 10 nanoseconds. The system described here has a grid-controlled rise time of less than 500 pico-seconds, and a minimum pulse width of less than 1 nanosecond. Pulse burst repetition rate has been demonstrated above 20 MHz during a 1.6 microsecond rf accelerating period. The order-of-magnitude increase in gun grid switching speed comes from a new gun design which minimizes lead inductance and stray capacitance, and also increases gun grid transconductance. These gun improvements coupled with a newly designed fast pulser mounted directly within the gun envelope make possible subnanosecond pulsing of the gun

Design and development of a pierce electron gun

International Nuclear Information System (INIS)

Bhattacharjee, D.; Tiwari, R.; Nayak, B.; Tillu, A.R.; Jayaprakash, D.; Mishra, R.L.; Mittal, K.C.; Chakravarthy, D.P.; Gantayet, L.M.

2011-01-01

An electron gun is designed and developed using the Pierce configuration for the focusing electrode. Simulations were carried out using CST Particle Studio. The Gun is a thermionic type electron gun with indirect heating of the LaB6 cathode. The gun is capable of delivering a beam current of 500 mA at 50 kV with a beam size of less than 3.5 mm. It was tested on the gun test bench. This paper presents the gun design, particle simulations study, testing of the gun on test bench and integration with the ECIL 9 MeV linac. (author)

Hot Gas Cleanup Test Facility for gasification and pressurized combustion. Quarterly report, October--December 1994

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-01

The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The major particulate control device issues to be addressed include the integration of the particulate control devices into coal utilization systems, on-line cleaning techniques, chemical and thermal degradation of components, fatigue or structural failures, blinding, collection efficiency as a function of particle size, and scale-up of particulate control systems to commercial size. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the original Transport Reactor gas source and Hot Gas Cleanup Units: carbonizer/pressurized circulating fluidized bed gas source; hot gas cleanup units to mate to all gas streams; combustion gas turbine; and fuel cell and associated gas treatment. The major emphasis during this reporting period was continuing the detailed design of the facility and integrating the particulate control devices (PCDs) into structural and process designs. Substantial progress in underground construction activities was achieved during the quarter. Delivery and construction of coal handling and process structural steel began during the quarter. Delivery and construction of coal handling and process structural steel began during the quarter. MWK equipment at the grade level and the first tier are being set in the structure.

Electron gun for the Fel Clio

International Nuclear Information System (INIS)

Chaput, R.

1990-01-01

A triode electron gun has been developed and manufactured at LURE (Laboratoire pour l'Utilisation du Rayonnement Electromagnetique) and LAL (Laboratoire de l'Accelerateur Lineaire) for the free electron laser CLIO 1 (Collaboration pour un laser a electrons libres dans l'infrarouge a Orsay) now under construction: this gun involves a grid-cathode assembly manufactured by EIMAC, currently used in the SLAC gun family. For the FEL requirements, the gun must be able to yield a train of short pulses at accuracy frequency or a continuous pulse. Driving together the cathode and the grid the gun produces a continous beam of 12 μs or a pulsed beam of very short pulse of 1 ns at 250 MHz, 125 MHz, 62.5 MHz or 31.25 MHz. The performances of the gun has been tested on a testing bench. A peak current of 1 Amp. for 1 ns width at any frequencies was achieved at an injection voltage of 90 kV

Ion Back-Bombardment of GaAs Photocathodes Inside DC High Voltage Electron Guns

CERN Document Server

Grames, Joseph M; Brittian, Joshua; Charles, Daniel; Clark, Jim; Hansknecht, John; Lynn Stutzman, Marcy; Poelker, Matthew; Surles-Law, Kenneth E

2005-01-01

The primary limitation for sustained high quantum efficiency operation of GaAs photocathodes inside DC high voltage electron guns is ion back-bombardment of the photocathode. This process results from ionization of residual gas within the cathode/anode gap by the extracted electron beam, which is subsequently accelerated backwards to the photocathode. The damage mechanism is believed to be either destruction of the negative electron affinity condition at the surface of the photocathode or damage to the crystal structure by implantation of the bombarding ions. This work characterizes ion formation within the anode/cathode gap for gas species typical of UHV vacuum chambers (i.e., hydrogen, carbon monoxide and methane). Calculations and simulations are performed to determine the ion trajectories and stopping distance within the photocathode material. The results of the simulations are compared with test results obtained using a 100 keV DC high voltage GaAs photoemission gun and beamline at currents up to 10 mA D...

1 ms pulse beam generation and acceleration by photo-cathode RF gun

International Nuclear Information System (INIS)

Watanabe, Ken; Hayano, Hitoshi; Urakawa, Jyunji

2012-01-01

We report successful generation of 1 ms long pulse and multi-bunch electron beam by a normal conducting photo-cathode RF gun at KEK-STF (Superconducting accelerator Test Facility). The 1 ms long Pulse beam generated by the RF gun is delivered to the injection line to examine stable acceleration and precise RF control. The 1 ms pulse beam is also used to demonstrate high brightness X-ray generation by inverse laser Compton scattering which will be also carried out at STF, supported by MEXT Quantum Beam project. The RF gun cavity has been fabricated by DESY-FNAL-KEK collaboration. Performing high power RF process and ethanol rinse to the cavity, a stable operation of the cavity up to 4.0 MW RF input power with ∼1 ms pulse length was achieved by keeping even low dark current. The beam generation test has been started since February 2012, 1 ms pulse was generated in March 2012. We explain about the STF injector and report the basic property of this 1 ms beam generation. (author)

Alignment Fixtures For Vacuum-Plasma-Spray Gun

Science.gov (United States)

Woodford, William H.; Mckechnie, Timothy N.; Power, Christopher A.; Daniel, Ronald L., Jr.

1993-01-01

Fixtures for alignment of vacuum-plasma-spray guns built. Each fixture designed to fit specific gun and holds small, battery-powered laser on centerline of gun. Laser beam projects small red dot where centerline intersects surface of workpiece to be sprayed. After laser beam positioned on surface of workpiece, fixture removed from gun and spraying proceeds.

Investigations of the magnetic structure and the decay of a plasma-gun-generated compact torus

International Nuclear Information System (INIS)

Turner, W.C.; Goldenbaum, G.C.; Granneman, E.H.A.; Hammer, J.H.; Hartman, C.W.; Prono, D.S.; Taska, J.

1983-01-01

The results of a series of experimental measurements of compact toroidal (CT) plasmas produced by a magnetized coaxial plasma gun injecting into a flux-conserving metallic liner are reported. The experiments were performed on the Beta II facility at Lawrence Livermore National Laboratory. The magnetic equilibria are well described by a force-free eigenmode structure that results from an extension of Taylor's theory of the reversed-field pinch. Consideration of helicity conservation during relaxation of the composite plasma-gun flux-conserver system to the final state equilibrium yields theoretical expressions that are compared with the experiment

Electron gun

International Nuclear Information System (INIS)

Chen, H.-Y.; Hughes, R.H.

1979-01-01

The invention described relates to cathode ray tubes, and particularly to color picture tubes of the type useful in home television receivers and therefore to electron guns. The invention is especially applicable to self-converging tube-yoke combinations with shadow mask tubes of the type having plural-beam in-line guns disposed in a horizontal plane, an apertured mask with vertically oriented slit-shaped apertures, and a screen with vertically oriented phosphor stripes. The invention is not, however, limited to use in such tubes and may in fact be used, e.g., in dot-type shadow mask tubes and index-type tubes. (Auth.)

3-D simulation study for a thermionic RF gun using an FDTD method

Energy Technology Data Exchange (ETDEWEB)

Hama, H. E-mail: hama@lns.tohoku.ac.jp; Hinode, F.; Shinto, K.; Miyamoto, A.; Tanaka, T

2004-08-01

Beam dynamics in a thermionic RF gun for a new pre-injector in a future synchrotron radiation facility at Tohoku university has been studied by developing a 3-D Maxwell's equation solver. Backbombardment (BB) effect on a cathode, which is a crucial problem for performance of the thermionic RF gun, has been investigated. It is found that an external dipole magnetic field applying around the cathode is effective to reduce high-energy backstreaming electrons from the accelerating cell. However, the low-energy electrons coming back from the first cell inevitably hit the cathode, so that characteristics of the cathode material seems to be crucial for reduction of the BB effect.

Operation of the APS rf gun

International Nuclear Information System (INIS)

Lewellen, J. W.

1998-01-01

The Advanced Photon Source (APS) has a thermionic-cathode rf gun system capable of providing beam to the APS linac. The gun system consists of a 1.6-cell thermionic-cathode rf gun, a fast kicker for beam current control, and an alpha magnet for bunch compression and injection into the APS linac line. This system is intended for use both as an injector for positron creation, and as a first beam source for the Low-Energy Undulator Test Line (LEUTL) project [1]. The first measured performance characteristics of the gun are presented.

Middle Ground on Gun Control

Science.gov (United States)

2016-12-01

34 Australian Institute of Criminology, July 7, 2015, http://www.aic.gov.au/ statistics /homicide/weapon.html. 0 100 200 300 400 500 600 700 Total Gun...firearms is not the business of a single Australian , so it is immeasurably easier for politicians to categorically ban types of guns because there is...not an Australian version of Smith and Wesson that is going to be put out of business . Additionally, because all of the guns in Australia are

Camouflaged Collectives: Managing Stigma and Identity at Gun Events

Directory of Open Access Journals (Sweden)

Sarah Jane Blithe

2017-02-01

Full Text Available Gun violence persists in the United States, claiming lives and escalating healthcare costs. This article seeks to contribute to social justice work on the “gun problem” by studying gun collectives. To understand gun culture and to identify gun violence reduction strategies, we study places where gun owners organize – legal (and sometimes illegal settings that facilitate dialogue about gun issues. Based on participant observation and collaborative event ethnography at gun shows and a private shooting party, this analysis presents findings about the practices gun collective members use to manage stigma. We conclude that when participants in gun events attempt to subvert core stigma through everyday stigma management practices, they effectively facilitate the unfettered exchange of potentially dangerous goods, promote the invisibility of oppressive structures, and normalize violence.

Interpreting the empirical evidence on illegal gun market dynamics.

Science.gov (United States)

Braga, Anthony A; Wintemute, Garen J; Pierce, Glenn L; Cook, Philip J; Ridgeway, Greg

2012-10-01

Thousands of Americans are killed by gunfire each year, and hundreds of thousands more are injured or threatened with guns in robberies and assaults. The burden of gun violence in urban areas is particularly high. Critics suggest that the results of firearm trace data and gun trafficking investigation studies cannot be used to understand the illegal supply of guns to criminals and, therefore, that regulatory and enforcement efforts designed to disrupt illegal firearms markets are futile in addressing criminal access to firearms. In this paper, we present new data to address three key arguments used by skeptics to undermine research on illegal gun market dynamics. We find that criminals rely upon a diverse set of illegal diversion pathways to acquire guns, gun traffickers usually divert small numbers of guns, newer guns are diverted through close-to-retail diversions from legal firearms commerce, and that a diverse set of gun trafficking indicators are needed to identify and shut down gun trafficking pathways.

Gun Safety (For Parents)

Science.gov (United States)

... from the home of a relative or friend. Teens should never be able to get to a gun and bullets without an adult being there. People of any age who are depressed are at increased risk of suicide. If someone in the family has depression, or has had thoughts of suicide, all guns ...

Remotely controlled spray gun

Science.gov (United States)

Cunningham, William C. (Inventor)

1987-01-01

A remotely controlled spray gun is described in which a nozzle and orifice plate are held in precise axial alignment by an alignment member, which in turn is held in alignment with the general outlet of the spray gun by insert. By this arrangement, the precise repeatability of spray patterns is insured.

Modeling electron beam parameters and plasma interface position in an anode plasma electron gun with hydrogen atmosphere

Science.gov (United States)

Krauze, A.; Virbulis, J.; Kravtsov, A.

2018-05-01

A beam glow discharge based electron gun can be applied as heater for silicon crystal growth systems in which silicon rods are pulled from melt. Impacts of high-energy charged particles cause wear and tear of the gun and generate an additional source of silicon contamination. A steady-state model for electron beam formation has been developed to model the electron gun and optimize its design. Description of the model and first simulation results are presented. It has been shown that the model can simulate dimensions of particle impact areas on the cathode and anode, but further improvements of the model are needed to correctly simulate electron trajectory distribution in the beam and the beam current dependence on the applied gas pressure.

Conceptual Design for CLIC Gun Pulser

Energy Technology Data Exchange (ETDEWEB)

Tang, Tao [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2016-01-08

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

Fueling by coaxial plasma guns

International Nuclear Information System (INIS)

Marshall, J.

1978-01-01

The operating principles of pulsed coaxial guns are reviewed. Some problems involved with the injection of plasma beams from these guns into containment fields are described. The injection during reactor operating conditions is then discussed

Fabrication and description of a cold cathode electron gun

International Nuclear Information System (INIS)

Sari, A.H.; Ghorannevis, M.; Hantehzadeh, M.R.; Yousefi, M.R.

2003-01-01

In this study the structure and schematic configuration of a cold cathode electron gun has been shown, which use obstructed discharge for electron producing. This type of discharge and mechanism of secondary electron emission by ions and fast neutral interaction have been described. The experiment starts in pressure of 1*10 -3 torr, in existence of helium gas. A negative DC voltage apply to a concave cathode up to -20 k V which determine electron energy

New Electron Gun System for BEPCII

CERN Document Server

Liu, Bo; Long Chi, Yun; Zhang, Chuang

2005-01-01

The new electron gun system for BEPCII has been put into operation since Nov. 2004. The article describes the design, experiment and operation of this new system. The design current of the gun is 10 A for the pulse lengths of 1 ns, 2.5 ns and 1 μs with repetition rate of 50 Hz. The gun is operated with a pulsed high voltage power supply which can provide up to 200 kV high voltage. Computer simulations have been carried out in the design stage, including simulation of the gun geometry and beam transportation. Some important relation curves are obtained during the experiment. Two-bunch operation is available and some elementary tests have been performed. New scheme of the gun control system based on EPICS is also presented. The real operation shows that the design and manufacturing is basically successful.

120 Hz Gun Review

Energy Technology Data Exchange (ETDEWEB)

Colby, E.

2005-01-31

The review was held at SLAC on September 11 and 12, 2001. Presentations concerning the thermal analysis, mechanical design, integration with the laser and accelerator, general beam dynamics considerations, a load lock mechanism, and symmetric power feed options comprised the review. Slides from these presentations are available elsewhere. The review committee was charged with evaluating the 120 Hz gun design including proposed load lock and power feed options and recommending improvements. Broader evaluation of the injector as a whole (including focusing and diagnostic systems that do no impact the envelope of the gun itself) is expected to be covered in a future review and will not be commented on here. In general, the long operational experience with four generations of s-band RF guns at numerous labs worldwide has led to considerable experience in design, fabrication, and operation aspects, and provides an excellent base on which to design the higher duty factor LCLS injector. While open questions remain on obtaining the design performance from these injectors, the microwave design of the gun has reached a state of relative maturity.

Solid state cesium ion guns for surface studies

International Nuclear Information System (INIS)

Souzis, A.E.; Carr, W.E.; Kim, S.I.; Seidl, M.

1990-01-01

Three cesium ion guns covering the energy range of 5--5000 V are described. These guns use a novel source of cesium ions that combine the advantages of porous metal ionizers with those of aluminosilicate emitters. Cesium ions are chemically stored in a solid electrolyte pellet and are thermionically emitted from a porous thin film of tungsten at the surface. Cesium supply to the emitting surface is controlled by applying a bias across the pellet. A total charge of 10.0 C can be extracted, corresponding to greater than 2000 h of lifetime with an extraction current of 1.0 μA. This source is compact, stable, and easy to use, and produces a beam with >99.5% purity. It requires none of the differential pumping or associated hardware necessary in designs using cesium vapor and porous tungsten ionizers. It has been used in ultrahigh-vacuum (UHV) experiments at pressures of -10 Torr with no significant gas load. Three different types of extraction optics are used depending on the energy range desired. For low-energy deposition, a simple space-charge-limited planar diode with a perveance of 1x10 -7 A/V 3/2 is used. Current densities of 10.0 μA/cm 2 at the exit aperture for energies ≤20 V are typical. This type of source provides an alternative to vapor deposition with the advantage of precise flux calibration by integration of the ion current. For energies from 50 to 500 V and typical beam radii of 0.5 to 0.2 mm, a high perveance Pierce-type ion gun is used. This gun was designed with a perveance of 1x10 -9 A/V 3/2 and produces a beam with an effective temperature of 0.35 eV. For the energy range of 0.5 to 5 keV, the Pierce gun is used in conjunction with two Einzel lenses, enabling a large range of imaging ratios to be obtained. Beam radii of 60 to 300 μm are typical for beam currents of 50 nA to 1.0 μA

Hot gas cleanup test facility for gasification and pressurized combustion. Quarterly technical progress report, July 1--September 30, 1992

Energy Technology Data Exchange (ETDEWEB)

1992-12-31

The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The major particulate control device issues to be addressed include the integration of the particulate control devices into coal utilization systems, on-line cleaning techniques, chemical and thermal degradation of components, fatigue or structural failures, blinding, collection efficiency as a function of particle size, and scale-up of particulate control systems to commercial size. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the existing Transport Reactor gas source and Hot Gas Cleanup Units: Carbonizer/Pressurized Circulating Fluidized Bed Gas Source; hot Gas Cleanup Units to mate to all gas streams; and Combustion Gas Turbine. Fuel Cell and associated gas treatment. This expansion to the Hot Gas Cleanup Test Facility is herein referred to as the Power Systems Development Facility (PSDF).

Gun Violence, mental health, and Connecticut physicians.

Science.gov (United States)

Dodds, Peter R; Anderson, Caitlyn O; Dodds, Jon H

2014-01-01

While there is a public perception that gun violence is associated with mental illness we present evidence that it is a complex public health problem which defies simple characterizations and solutions. Only a small percentage of individuals with mental illness are at risk for extreme violence and they account for only a small percentage of gun-related homicides. Individuals who are at risk for gun violence are difficult to identify and successfully treat. The incidence, and perhaps the demographics, of gun violence vary substantially from state to state. We make a case for Connecticut physicians to study gun violence at the state level. We recommend that Connecticut physicians promote and expand upon the American Academy of Pediatrics' recommendation for creating a "safe home environment. "We suggest that guns be secured in all homes in which there are children. In addition we suggest that guns be voluntarily removed from homes in which there are individuals with a history of violence, threats of violence, depression, drug and/or alcohol abuse, and individuals with major mental illnesses who are not cooperating with therapy.

Testing of a prototype of calibration facility for noble gas monitoring using 41Ar

International Nuclear Information System (INIS)

Saibathulham, Holnisar; Wurdiyanto, Gatot; Marsum, Pujadi

2012-01-01

A prototype of a calibration facility for noble gas monitoring using 41 Ar in the PTKMR-BATAN has been tested. The facility was designed in such a way that the standard source of gas can be reused. The radioactive 41 Ar source was obtained by thermal neutron reaction of 40 Ar(n, γ) 41 Ar using a thermal neutron flux of 4.8×10 13 neutrons per cm 2 per second in two minutes on the multipurpose G.A. Siwabessy Reactor (Batan, Serpong, Indonesia). Gamma spectrometry was used to measure the radioactivity and purity of 41 Ar. The spectrum of the 41 Ar observed yields an energy of 1294 keV because of the highest intensity (99.2%). The activity of 41 Ar was 2821 kBq and 4% of the expanded uncertainty. The time required for 41 Ar to reach homogeneity was 7 min, and the effectiveness of resuse was 53%. - Highlights: ► Testing of a calibration facility prototype for noble gas monitor using 41 Ar in PTKMR-BATAN. ► This facility was designed such that a standard radioactive gas source can be used repeatedly. ► Standardization of the 41 Ar is performed using gamma spectrometry. ► The time required for the 41 Ar gas to be distributed evenly throughout the cavity of the facility was 7 min. ► The effectiveness of repeated use was 53%.

Electric rail gun application to space propulsion

International Nuclear Information System (INIS)

Barber, J.P.

1979-01-01

The paper examines the possibility of using the DC electric gun principles as a space vehicle propulsion system, capable of producing intermediate thrust levels. The application of an electromagnetic launch technique, called the DC electric rail gun, to the space propulsion concept of O'Neill, is examined. It is determined that the DC electric rail gun offers very high projectile accelerations and a very significant potential for reducing the size and mass of a reaction motor for space application. A detailed description of rail gun principles is given and some simple expressions for the accelerating force, gun impedance, power supply requirements, and system performance are discussed

Association Between Substance Use and Gun-Related Behaviors.

Science.gov (United States)

Chen, Danhong; Wu, Li-Tzy

2016-01-01

Gun-related violence is a public health concern. This study synthesizes findings on associations between substance use and gun-related behaviors. Searches through PubMed, Embase, and PsycINFO located 66 studies published in English between 1992 and 2014. Most studies found a significant bivariate association between substance use and increased odds of gun-related behaviors. However, their association after adjustment was mixed, which could be attributed to a number of factors such as variations in definitions of substance use and gun activity, study design, sample demographics, and the specific covariates considered. Fewer studies identified a significant association between substance use and gun access/possession than other gun activities. The significant association between nonsubstance covariates (e.g., demographic covariates and other behavioral risk factors) and gun-related behaviors might have moderated the association between substance use and gun activities. Particularly, the strength of association between substance use and gun activities tended to reduce appreciably or to become nonsignificant after adjustment for mental disorders. Some studies indicated a positive association between the frequency of substance use and the odds of engaging in gun-related behaviors. Overall, the results suggest a need to consider substance use in research and prevention programs for gun-related violence. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

First operational tests of an oxycoal hot gas cleaning facility; Erste Betriebstests einer Oxycoal-Heissgasreinigung

Energy Technology Data Exchange (ETDEWEB)

Kellermann, A.; Habermehl, M.; Foerster, M.; Kneer, R. [RWTH Aachen University (Germany). Lehrstuhl fuer Waerme- und Stoffuebertragung

2009-07-01

An oxyfuel power plant process using a ceramic high temperature membrane for oxygen supply is investigated within the scope of the OXYCOAL-AC project at RWTH Aachen Uni-versity. Implementing the membrane requires a clean gas at a temperature of 850 C. There-fore a hot gas cleaning facility based on porous ceramic candle filters is used, which is state-of-the-art for the gas cleaning of synthesis gas or for flue gas cleaning in pressurised fluid-ised bed furnaces. However, these applications operate at lower temperatures and in a sig-nificantly different atmosphere. Thus, experiences for dust removal at high temperatures in oxyfuel atmoshere are not available. Experiments with a hot gas cleaning facility were con-ducted at the experimental combustion plant of the Institute of Heat and Mass Transfer, us-ing different candle filter materials. The flue gas was provided by a coal fired 100 kW{sub th} oxy-fuel furnace. The operational behaviour of the filtration facility, the adhesion and dedusting properties of the filter cake were investigated. (orig.)

Performance Improvement of a Magnetized Coaxial Plasma Gun by adopting Iron-core Bias Coil and New Pre-Ionization System

Science.gov (United States)

Edo, Takahiro; Asai, T.; Tanaka, F.; Yamada, S.; Hosozawa, A.; Gota, H.; Roche, T.; Allfrey, I.; Matsumoto, T.

2017-10-01

A magnetized coaxial plasma gun (MCPG) is a device used to generate a compact toroid (CT), which has a spheromak-like configuration. A typical MCPG consists of a set of axisymmetric cylindrical electrodes, bias coil, and gas-puff valves. In order to expand the CT operating range, the distributions of the bias magnetic field and neutral gas have been investigated. We have developed a new means of generating stuffing flux. By inserting an iron core into the bias coil, the magnetic field increases dramatically; even a small current of a few Amps produces a sufficient bias field. According to a simulation result, it was also suggested that the radial distribution of the bias field is easily controlled. The ejected CT and the target FRC are cooled by excess neutral gas that typical MCPGs require to initiate a breakdown; therefore, we have adopted a miniature gun as a new pre-ionization (PI) system. By introducing this PI system, the breakdown occurs at lower neutral gas density so that the amount of excess neutral gas can be reduced.

Brief use of a specific gun in a violent game does not affect attitudes towards that gun.

Science.gov (United States)

Hilgard, Joseph; Engelhardt, Christopher R; Bartholow, Bruce D

2016-11-01

Although much attention has been paid to the question of whether violent video games increase aggressive behaviour, little attention has been paid to how such games might encourage antecedents of gun violence. In this study, we examined how product placement, the attractive in-game presentation of certain real-world firearm brands, might encourage gun ownership, a necessary antecedent of gun violence. We sought to study how the virtual portrayal of a real-world firearm (the Bushmaster AR-15) could influence players' attitudes towards the AR-15 specifically and gun ownership in general. College undergraduates ( N  = 176) played one of four modified video games in a 2 (gun: AR-15 or science-fiction control) × 2 (gun power: strong or weak) between-subjects design. Despite collecting many outcomes and examining many potential covariates and moderators, experimental assignment did little to influence outcomes of product evaluations or purchasing intentions with regard to the AR-15. Attitudes towards public policy and estimation of gun safety were also not influenced by experimental condition, although these might have been better tested by comparison against a no-violence control condition. By contrast, gender and political party had dramatic associations with all outcomes. We conclude that, if product placement shapes attitudes towards firearms, such effects will need to be studied with stronger manipulations or more sensitive measures.

Brief use of a specific gun in a violent game does not affect attitudes towards that gun

Science.gov (United States)

Engelhardt, Christopher R.; Bartholow, Bruce D.

2016-01-01

Although much attention has been paid to the question of whether violent video games increase aggressive behaviour, little attention has been paid to how such games might encourage antecedents of gun violence. In this study, we examined how product placement, the attractive in-game presentation of certain real-world firearm brands, might encourage gun ownership, a necessary antecedent of gun violence. We sought to study how the virtual portrayal of a real-world firearm (the Bushmaster AR-15) could influence players' attitudes towards the AR-15 specifically and gun ownership in general. College undergraduates (N = 176) played one of four modified video games in a 2 (gun: AR-15 or science-fiction control) × 2 (gun power: strong or weak) between-subjects design. Despite collecting many outcomes and examining many potential covariates and moderators, experimental assignment did little to influence outcomes of product evaluations or purchasing intentions with regard to the AR-15. Attitudes towards public policy and estimation of gun safety were also not influenced by experimental condition, although these might have been better tested by comparison against a no-violence control condition. By contrast, gender and political party had dramatic associations with all outcomes. We conclude that, if product placement shapes attitudes towards firearms, such effects will need to be studied with stronger manipulations or more sensitive measures. PMID:28018611

Nail gun injuries among construction workers.

Science.gov (United States)

Dement, John M; Lipscomb, Hester; Li, Leiming; Epling, Carol; Desai, Tejas

2003-05-01

Pneumatic nail guns greatly increase worker productivity and are extensively used in wood frame building construction, with especially high use in residential construction. One surveillance report of nail gun injuries in Washington State has been published; however, other literature consists largely of case reports and case series in trauma journals. The major objective of the current study was to investigate the occurrence of nail gun-associated injuries among construction workers and to identify preventable work-related factors associated with these injuries. Nail gun-related injuries occurring among a cohort of 13,347 carpenters in Ohio who worked union hours during the time period January 1, 1994, until September 30, 1997, were identified by matching the cohort with workers' compensation claims made to the Ohio Bureau of Workers' Compensation. We also analyzed workers' compensation claims for North Carolina Home Builders Association members for the period July 1996-November 1999 to identify nail gun-related injuries. Analyses included stratified analyses of claims by nature and body part injured, calculation of nail gun injury rates, and analyses of free text descriptions of injuries. Overall, nail gun injuries were responsible for 3.9 percent of workers' compensation claims with 8.3 percent to 25.5 percent of claims involving paid lost work time. The overall rate of nail gun injuries (cases per 200,000 work hours) was 0.33 in North Carolina and 0.26 in Ohio, reflecting the greater concentration of wood frame construction workers in the North Carolina population studied. Higher rates of injury were observed for carpenters in North Carolina and among residential carpenters in Ohio. The predominant body part injured was the hands/fingers, with 80 to 89 percent of injuries being nail punctures. Analyses of free text information for puncture injuries found approximately 70 percent of injuries to occur during the framing/sheathing stage of construction. Our data

Rail gun powered by an integral explosive generator

International Nuclear Information System (INIS)

Peterson, D.R.; Fowler, C.M.

1979-01-01

We propose the use of a rail gun powered by an explosive magnetic flux compression generator built into the rail gun itself in which the rails of the gun are driven together behind the projectile by explosives. The magnetic field established between the rails by an initial current supplied by an external source at the breech of the gun is trapped and compressed by the collapsing rails to accelerate the projectile down the bore of the gun

GUN4-Porphyrin Complexes Bind the ChlH/GUN5 Subunit of Mg-Chelatase and Promote Chlorophyll Biosynthesis in Arabidopsis[W

Science.gov (United States)

Adhikari, Neil D.; Froehlich, John E.; Strand, Deserah D.; Buck, Stephanie M.; Kramer, David M.; Larkin, Robert M.

2011-01-01

The GENOMES UNCOUPLED4 (GUN4) protein stimulates chlorophyll biosynthesis by activating Mg-chelatase, the enzyme that commits protoporphyrin IX to chlorophyll biosynthesis. This stimulation depends on GUN4 binding the ChlH subunit of Mg-chelatase and the porphyrin substrate and product of Mg-chelatase. After binding porphyrins, GUN4 associates more stably with chloroplast membranes and was proposed to promote interactions between ChlH and chloroplast membranes—the site of Mg-chelatase activity. GUN4 was also proposed to attenuate the production of reactive oxygen species (ROS) by binding and shielding light-exposed porphyrins from collisions with O2. To test these proposals, we first engineered Arabidopsis thaliana plants that express only porphyrin binding–deficient forms of GUN4. Using these transgenic plants and particular mutants, we found that the porphyrin binding activity of GUN4 and Mg-chelatase contribute to the accumulation of chlorophyll, GUN4, and Mg-chelatase subunits. Also, we found that the porphyrin binding activity of GUN4 and Mg-chelatase affect the associations of GUN4 and ChlH with chloroplast membranes and have various effects on the expression of ROS-inducible genes. Based on our findings, we conclude that ChlH and GUN4 use distinct mechanisms to associate with chloroplast membranes and that mutant alleles of GUN4 and Mg-chelatase genes cause sensitivity to intense light by a mechanism that is potentially complex. PMID:21467578

Rate control for electron gun evaporation

International Nuclear Information System (INIS)

Schellingerhout, A.J.G.; Janocko, M.A.; Klapwijk, T.M.; Mooij, J.E.

1989-01-01

Principles for obtaining high-quality rate control for electron gun evaporation are discussed. The design criteria for rate controllers are derived from this analysis. Results are presented which have been obtained with e-guns whose evaporation rate is controlled by a Wehnelt electrode or by sweeping of the electron beam. Further improvements of rate stability can be obtained by improved design of e-guns and power supplies

Background Checks for all Gun Buyers and Gun Violence Restraining Orders: State Efforts to Keep Guns from High-Risk Persons.

Science.gov (United States)

Vernick, Jon S; Alcorn, Ted; Horwitz, Joshua

2017-03-01

There were more than 36,000 firearm-related deaths in the U.S. in 2015. Under federal law, a background check is required only for gun purchases from licensed dealers. Research suggests that some persons prohibited from owning a gun turn to private sellers, including those identified online, to attempt to obtain a firearm. State-level approaches to make it more difficult for high-risk persons to purchase or possess firearms include universal background check (UBC) and gun violence restraining order (GVRO) laws. UBC laws, on the books in 18 states as of the end of 2016, can reduce both homicide and suicide rates. After Colorado adopted a UBC law in 2013, the number of background checks conducted by private sellers for sales occurring at places other than gun shows steadily increased. GVRO laws give law enforcement and families the authority to petition a court to temporarily remove firearms from an individual who presents a danger to himself or others during times of crisis, regardless of whether that person has been diagnosed with a mental illness. California enacted a GVRO law in 2014. Data are emerging to suggest the effectiveness of GVRO-type laws at averting suicides and providing an entryway to services.

Canadian development program for off-gas management in nuclear facilities

International Nuclear Information System (INIS)

Sridhar, T.S.

1983-01-01

The Canadian program for the development and evaluation of processes and technology for the separation and containment of radioactive species in off-gases is directed towards the following specific aspects: 1) assessment of available treatment technology and evaluation of future clean-up requirements; 2) development and engineering evaluation, under realistic conditions, of promising new processes that would be inherently simpler and safer; and 3) specification of off-gas emission control systems for future nuclear facilities based on the most favourable technology. The program is being carried out by Atomic Energy of Canada Limited in collaboration with the electrical utility, Ontario Hydro, and selected Canadian universities. A brief description is presented of methods for removing tritium and carbon-14 from the moderator systems of CANDU power reactors, methods for removing iodine from the off-gases of a molybdenum-99 production facility at the Chalk River Nuclear Laboratories, and procedures for monitoring the off-gas effluent composition in the Thorium Fuel Reprocessing Experiment (TFRE) facility at the Whiteshell Nuclear Research Establishment

Map of gas facilities and operators in Northeast British Columbia

Energy Technology Data Exchange (ETDEWEB)

Anon.

2005-06-01

This map represents 57 gas facilities and operators and references location on the map to the facility and operator. The Northern Rockies Regional district is indicated, as is the Peace River Regional district. Roads, truck trails, railroads, pipeline and airstrips are indicated as well as oil and gas fields. Various protected areas and First Nations settlement areas and regions are also indicated. The following companies placed advertisements on the map, detailing the services they provide: Wellco Energy Services; C.E. Franklin Ltd.; the City of Fort St. John, Region of Chetwynd; Smith Bits; the City of Dawson Creek, Economic Development and Tourism; Fort Nelson and Northern Rockies Regional District; Pipetech Corp.; Kenwood; Hughes Christensen; Spartan Controls; FI Canada Oil Services Ltd.; Northstar Drillstem Testers Inc.; Rainbow Transport Ltd.1 fig.

Testing a GaAs cathode in SRF gun

International Nuclear Information System (INIS)

Wang, E.; Kewisch, J.; Ben-Zvi, I.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

2011-01-01

RF electron guns with a strained superlattice GaAs cathode are expected to generate polarized electron beams of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface and lower cathode temperature. We plan to install a bulk GaAs:Cs in a SRF gun to evaluate the performance of both the gun and the cathode in this environment. The status of this project is: In our 1.3 GHz 1/2 cell SRF gun, the vacuum can be maintained at nearly 10 -12 Torr because of cryo-pumping at 2K. With conventional activation of bulk GaAs, we obtained a QE of 10% at 532 nm, with lifetime of more than 3 days in the preparation chamber and have shown that it can survive in transport from the preparation chamber to the gun. The beam line has been assembled and we are exploring the best conditions for baking the cathode under vacuum. We report here the progress of our test of the GaAs cathode in the SRF gun. Future particle accelerators, such as eRHIC and the ILC require high-brightness, high-current polarized electrons. Strained superlattice GaAs:Cs has been shown to be an efficient cathode for producing polarized electrons. Activation of GaAs with Cs,O(F) lowers the electron affinity and makes it energetically possible for all the electrons, excited into the conduction band that drift or diffuse to the emission surface, to escape into the vacuum. Presently, all operating polarized electron sources, such as the CEBAF, are DC guns. In these devices, the excellent ultra-high vacuum extends the lifetime of the cathode. However, the low field gradient on the photocathode's emission surface of the DC guns limits the beam quality. The higher accelerating gradients, possible in the RF guns, generate a far better beam. Until recently, most RF guns operated at room temperature, limiting the vacuum to ∼10 -9 Torr. This destroys the GaAs's NEA surface. The SRF guns combine the excellent vacuum conditions of DC guns and the high accelerating

Extended suicide using an atypical stud gun.

Science.gov (United States)

Hagemeier, L; Schyma, C; Madea, B

2009-08-10

Suicides with stud guns are uncommon, but are well documented in the literature. On rare occasions, stud guns are also used as a homicide weapon. This case report describes an extended suicide in which a husband killed his wife and their two dogs, which lived on the property. The husband then committed suicide with a shot from the stud gun into his skull. He was a 70-year-old pensioner, a retired butcher, who was found by his son. He was lying in a supine position on a carpet in the living room, with the stud gun stuck in his skull. During autopsy, high concentrations of an antihistamine were found in the blood of each corpse; this drug is used as a soporific. In contrast to the literature, which mainly describes powder deposits due to the use of conventional stud guns, in this case a stud gun was used in which the expanding gases and powder escaped together with the central bolt at the front of the device; powder drains were not involved. Detailed findings of the autopsy are given with reference to this type of stud gun.

Investigations and Applications of Field- and Photo-emitted Electron Beams from a Radio Frequency Gun

Energy Technology Data Exchange (ETDEWEB)

Panuganti, SriHarsha [Northern Illinois Univ., DeKalb, IL (United States)

2015-08-01

Production of quality electron bunches using e cient ways of generation is a crucial aspect of accelerator technology. Radio frequency electron guns are widely used to generate and rapidly accelerate electron beams to relativistic energies. In the current work, we primarily study the charge generation processes of photoemission and eld emission inside an RF gun installed at Fermilab's High Brightness Electron Source Laboratory (HBESL). Speci cally, we study and characterize second-order nonlinear photoemission from a Cesium Telluride (Cs₂Te) semiconductor photocathode, and eld emission from carbon based cathodes including diamond eld emission array (DFEA) and carbon nanotube (CNT) cathodes located in the RF gun's cavity. Finally, we discuss the application experiments conducted at the facility to produce soft x-rays via inverse Compton scattering (ICS), and to generate uniformly lled ellipsoidal bunches and temporally shaped electron beams from the Cs₂Te photocathode.

Ready, Fire, Aim: The College Campus Gun Fight

Science.gov (United States)

Birnbaum, Robert

2013-01-01

The question of whether guns should be permitted on college and university campuses in the United States reflects the tension between two competing perspectives. America has both a robust gun culture and an equally robust (if less well known) gun-control culture. The gun culture is as American as apple pie: There may be as many as 300 million…

Design and operation of off-gas cleaning systems at high level liquid waste conditioning facilities

International Nuclear Information System (INIS)

1988-01-01

The immobilization of high level liquid wastes from the reprocessing of irradiated nuclear fuels is of great interest and serious efforts are being undertaken to find a satisfactory technical solution. Volatilization of fission product elements during immobilization poses the potential for the release of radioactive substances to the environment and necessitates effective off-gas cleaning systems. This report describes typical off-gas cleaning systems used in the most advanced high level liquid waste immobilization plants and considers most of the equipment and components which can be used for the efficient retention of the aerosols and volatile contaminants. In the case of a nuclear facility consisting of several different facilities, release limits are generally prescribed for the nuclear facility as a whole. Since high level liquid waste conditioning (calcination, vitrification, etc.) facilities are usually located at fuel reprocessing sites (where the majority of the high level liquid wastes originates), the off-gas cleaning system should be designed so that the airborne radioactivity discharge of the whole site, including the emission of the waste conditioning facility, can be kept below the permitted limits. This report deals with the sources and composition of different kinds of high level liquid wastes and describes briefly the main high level liquid waste solidification processes examining the sources and characteristics of the off-gas contaminants to be retained by the off-gas cleaning system. The equipment and components of typical off-gas systems used in the most advanced (large pilot or industrial scale) high level liquid waste solidification plants are described. Safety considerations for the design and safe operation of the off-gas systems are discussed. 60 refs, 31 figs, 17 tabs

Reducing Energy Degradation Due to Back-bombardment Effect with Modulated RF Input in S-band Thermionic RF Gun

Science.gov (United States)

Kii, Toshiteru; Nakai, Yoko; Fukui, Toshio; Zen, Heishun; Kusukame, Kohichi; Okawachi, Norihito; Nakano, Masatsugu; Masuda, Kai; Ohgaki, Hideaki; Yoshikawa, Kiyoshi; Yamazaki, Tetsuo

2007-01-01

Energy degradation due to back-bombardment effect is quite serious to produce high-brightness electron beam with long macro-pulse with thermionic rf gun. To avoid the back-bombardment problem, a laser photo cathode is used at many FEL facilities, but usually it costs high and not easy to operate. Thus we have studied long pulse operation of the rf gun with thermionic cathode, which is inexpensive and easy to operate compared to the photocathode rf gun. In this work, to reduce the energy degradation, we controlled input rf power amplitude by controlling pulse forming network of the power modulator for klystron. We have successfully increased the pulse duration up to 4 μs by increasing the rf power from 7.8 MW to 8.5 MW during the macro pulse.

DC photoemission electron guns as ERL sources

International Nuclear Information System (INIS)

Sinclair, Charles K.

2006-01-01

Very-high-voltage DC electron guns, delivering moderate duration bunches from photoemission cathodes, and followed by conventional drift bunching and acceleration, offer a practical solution for an ERL injector. In a variant of this scheme, a DC gun is placed in close proximity to a superconducting RF accelerator cavity, with few or no active elements between the gun and cavity. The principal technical challenge with such electron guns arises from field emission from the cathode electrode and its support structure. Field emission may result in voltage breakdown across the cathode-anode gap, or a punch-through failure of the insulator holding off the cathode potential, as well as lesser though still serious problems. Various means to mitigate these problems are described. The operational lifetime of high quantum efficiency photocathodes in these guns is determined by the vacuum conditions, through phenomena such as chemical poisoning and ion back-bombardment. Minimization of the field strength on electrode structures pushes high-voltage DC guns toward large dimensions and, correspondingly, large outgassing loads, but it is also true that these guns offer many opportunities for achieving excellent vacuum conditions. Good solutions to vacuum problems that had previously limited cathode lifetime have been demonstrated in recent years. Designs for DC guns presently in use and planned for the near future will be described. The parameters necessary for a 100 mA average current, very-high-voltage DC gun with a photocathode operational lifetime greater than 100 h appear to be within reach, but have yet to be demonstrated. A 1 A average current source with good cathode operational lifetime will require developments beyond the present state-of-the-art

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

Energy Technology Data Exchange (ETDEWEB)

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A. [High Temperature Gasdynamics Laboratory, Stanford University, Stanford, California 94305 (United States)

2013-07-15

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

International Nuclear Information System (INIS)

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

2013-01-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

Science.gov (United States)

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

2013-07-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode.

Science.gov (United States)

Rieker, G B; Poehlmann, F R; Cappelli, M A

2013-07-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

Gun possession among American youth: a discovery-based approach to understand gun violence.

Science.gov (United States)

Ruggles, Kelly V; Rajan, Sonali

2014-01-01

To apply discovery-based computational methods to nationally representative data from the Centers for Disease Control and Preventions' Youth Risk Behavior Surveillance System to better understand and visualize the behavioral factors associated with gun possession among adolescent youth. Our study uncovered the multidimensional nature of gun possession across nearly five million unique data points over a ten year period (2001-2011). Specifically, we automated odds ratio calculations for 55 risk behaviors to assemble a comprehensive table of associations for every behavior combination. Downstream analyses included the hierarchical clustering of risk behaviors based on their association "fingerprint" to 1) visualize and assess which behaviors frequently co-occur and 2) evaluate which risk behaviors are consistently found to be associated with gun possession. From these analyses, we identified more than 40 behavioral factors, including heroin use, using snuff on school property, having been injured in a fight, and having been a victim of sexual violence, that have and continue to be strongly associated with gun possession. Additionally, we identified six behavioral clusters based on association similarities: 1) physical activity and nutrition; 2) disordered eating, suicide and sexual violence; 3) weapon carrying and physical safety; 4) alcohol, marijuana and cigarette use; 5) drug use on school property and 6) overall drug use. Use of computational methodologies identified multiple risk behaviors, beyond more commonly discussed indicators of poor mental health, that are associated with gun possession among youth. Implications for prevention efforts and future interdisciplinary work applying computational methods to behavioral science data are described.

Gun possession among American youth: a discovery-based approach to understand gun violence.

Directory of Open Access Journals (Sweden)

Kelly V Ruggles

Full Text Available OBJECTIVE: To apply discovery-based computational methods to nationally representative data from the Centers for Disease Control and Preventions' Youth Risk Behavior Surveillance System to better understand and visualize the behavioral factors associated with gun possession among adolescent youth. RESULTS: Our study uncovered the multidimensional nature of gun possession across nearly five million unique data points over a ten year period (2001-2011. Specifically, we automated odds ratio calculations for 55 risk behaviors to assemble a comprehensive table of associations for every behavior combination. Downstream analyses included the hierarchical clustering of risk behaviors based on their association "fingerprint" to 1 visualize and assess which behaviors frequently co-occur and 2 evaluate which risk behaviors are consistently found to be associated with gun possession. From these analyses, we identified more than 40 behavioral factors, including heroin use, using snuff on school property, having been injured in a fight, and having been a victim of sexual violence, that have and continue to be strongly associated with gun possession. Additionally, we identified six behavioral clusters based on association similarities: 1 physical activity and nutrition; 2 disordered eating, suicide and sexual violence; 3 weapon carrying and physical safety; 4 alcohol, marijuana and cigarette use; 5 drug use on school property and 6 overall drug use. CONCLUSIONS: Use of computational methodologies identified multiple risk behaviors, beyond more commonly discussed indicators of poor mental health, that are associated with gun possession among youth. Implications for prevention efforts and future interdisciplinary work applying computational methods to behavioral science data are described.

Design of the BEPCII electron gun system

International Nuclear Information System (INIS)

Liu Bo; Gu Mengping; Chi Yunlong

2006-01-01

BEPCII upgrading project needs a new high current electron gun. The design stage such as physical design, mechanical design and control system design of this new electron gun is described. The emission current is designed to be higher than 10 A for the pulse width of 1 ns with repetition rate of 50 Hz. The gun will operate with a pulsed high voltage power supply which can provide up to 200 kV high voltage. Computer simulations and optimizations have been carried out in the design stage, including the gun geometry and beam transport. EGUN and DGUN codes are used to simulate the gun geometry, and the results show that the perveance is about 0.22 μA·V -3/2 , and the emittance at gun exit is about 16 π·mm·mrad. PARMELA code shows that the electron beam can be easily transported to the end of the first accelerating tube with a capture efficiency of 67% and root mean square emittance of 25 mm·mrad. New scheme of the gun control system based on EPICS is also presented. Two-bunch operation mode and 2.5 μs long pulse operation mode are available in the control system. (authors)

Combustible gas concentration control facility and operation method therefor

International Nuclear Information System (INIS)

Yoshikawa, Kazuhiro; Ando, Koji; Kinoshita, Shoichiro; Yamanari, Shozo; Moriya, Kimiaki; Karasawa, Hidetoshi

1998-01-01

The present invention provides a hydrogen gas-control facility by using a fuel battery-type combustible gas concentration reducing device as a countermeasure for controlling a hydrogen gas in a reactor container. Namely, a hydrogen electrode adsorb hydrogen by using an ion exchange membrane comprising hydrogen ions as a charge carrier. An air electrode adsorb oxygen in the air. A fuel battery converts recombining energy of hydrogen and oxygen to electric energy. Hydrogen in this case is supplied from an atmosphere in the container. Oxygen in this case is supplied from the air outside of the container. If hydrogen gas should be generated in the reactor, power generation of is performed by the fuel battery by using hydrogen gas, as a fuel, on the side of the hydrogen electrode of the fuel battery and using oxygen, as a fuel, in the air outside of the container on the side of the air electrode. Then, the hydrogen gas is consumed thereby controlling the hydrogen gas concentration in the container. Electric current generated in the fuel battery is used as an emergency power source for the countermeasure for a severe accident. (I.S.)

Combustible gas concentration control facility and operation method therefor

Energy Technology Data Exchange (ETDEWEB)

Yoshikawa, Kazuhiro; Ando, Koji; Kinoshita, Shoichiro; Yamanari, Shozo; Moriya, Kimiaki; Karasawa, Hidetoshi

1998-09-25

The present invention provides a hydrogen gas-control facility by using a fuel battery-type combustible gas concentration reducing device as a countermeasure for controlling a hydrogen gas in a reactor container. Namely, a hydrogen electrode adsorb hydrogen by using an ion exchange membrane comprising hydrogen ions as a charge carrier. An air electrode adsorb oxygen in the air. A fuel battery converts recombining energy of hydrogen and oxygen to electric energy. Hydrogen in this case is supplied from an atmosphere in the container. Oxygen in this case is supplied from the air outside of the container. If hydrogen gas should be generated in the reactor, power generation of is performed by the fuel battery by using hydrogen gas, as a fuel, on the side of the hydrogen electrode of the fuel battery and using oxygen, as a fuel, in the air outside of the container on the side of the air electrode. Then, the hydrogen gas is consumed thereby controlling the hydrogen gas concentration in the container. Electric current generated in the fuel battery is used as an emergency power source for the countermeasure for a severe accident. (I.S.)

Research on Miniature Calibre Rail-Guns for the Mechanical Arm

Directory of Open Access Journals (Sweden)

Ronggang Cao

2017-01-01

Full Text Available Rail-gun should not only be used to military applications, but also can be developed as applications in the civilian aspects of the market. With the development of the electromagnetic launch technology, based on the similarity theory, using the existing rail-gun model to guide the construction of more economical miniature calibre rail-guns, and apply it in some machinery and equipment, this idea will open up a wider rail-gun application space. This article will focus on the feasibility of application of miniature calibre rail-guns in the mechanical arm. This paper designs the schematic diagram, then theoretical analyzes force conditions of the armature in the mechanical arm, calculates the possible range of the current amplitude and so on. The existing rail-gun model can be used to guides design the circuit diagram of the miniature calibre rail-gun. Based on the similarity theory and many simulation experiments, designed the experimental parameters of a miniature rail-gun and analyzed the current, Lorentz force, velocity, and location of the existing rail-gun and miniature rail-gun. The results show that the rail-gun launching technology applied to robot arms is feasibility. The application of miniature calibre rail-guns in the mechanical arm will benefit to the further development of rail-guns.

Weaker gun state laws are associated with higher rates of suicide secondary to firearms.

Science.gov (United States)

Alban, Rodrigo F; Nuño, Miriam; Ko, Ara; Barmparas, Galinos; Lewis, Azaria V; Margulies, Daniel R

2018-01-01

Firearm-related suicides comprise over two-thirds of gun-related violence in the United States, and gun laws and policies remain under scrutiny, with many advocating for revision of the regulatory map for lawful gun ownership, aiming at restricting access and distribution of these weapons. However, the quantitative relationship between how strict gun laws are and the incidence of firearm violence with their associated mortality is largely unknown. We therefore, sought to explore the impact of firearm law patterns among states on the incidence and outcomes of firearm-related suicide attempts, utilizing established objective criteria. The National Inpatient Sample for the years 1998-2011 was queried for all firearm-related suicides. Discharge facilities were stratified into five categories (A, B, C, D, and F, with A representing states with the most strict and F representing states with the least strict laws) based on the Brady Campaign to prevent Gun Violence that assigns scorecards for every state. The primary outcomes were suicide attempts and in-hospital mortality per 100,000 populations by Brady state grade. During the 14-year study period, 34,994 subjects met inclusion criteria. The mean age was 42.0 years and 80.1% were male. A handgun was utilized by 51.8% of patients. The overall mortality was 33.3%. Overall, 22.0% had reported psychoses and 19.3% reported depression. After adjusting for confounding factors and using group A as reference, there were higher adjusted odds for suicide attempts for patients admitted in group C, D, and F category states (1.73, 2.09, and 1.65, respectively, all P gun laws, and these injuries tend to be associated with a higher mortality. Efforts aimed at nationwide standardization of firearm state laws are warranted, particularly for young adults and suicide-prone populations. III. Trauma Outcomes study. Copyright © 2017 Elsevier Inc. All rights reserved.

The electron gun for the Daresbury SRS linac

International Nuclear Information System (INIS)

Dykes, D.M.

1996-01-01

The electron gun for the Daresbury SRS linac injector has been modified to use the cathode-grid assembly from the Eimac planar triode 8755. The gun now has improved beam characteristics, is more reliable and the cathode assembly is quicker and easier to change. This paper describes the assembly of the electron gun, and then the re-conditioning of the cathode highlighting the vacuum environment. The action of the grid modulation system on the electron beam, which pre-bunches the electron beam, is described, and typical gun characteristics are shown. Proposed developments to the gun system are discussed. (author)

Simulation of electron beam from two strip electron guns and control of power density by rotation of gun

International Nuclear Information System (INIS)

Sahu, G K; Baruah, S; Thakur, K B

2012-01-01

Electron beam is preferably used for large scale evaporation of refractory materials. Material evaporation from a long and narrow source providing a well collimated wedge shaped atomic beam has applications in isotopic purification of metals relevant to nuclear industry. The electron beam from an electron gun with strip type filament provides a linear heating source. However, the high power density of the electron beam can lead to turbulence of the melt pool and undesirable splashing of molten metal. For obtaining quiet surface evaporation, the linear electron beam is generally scanned along its length. To further reduce the power density to maintain quiet evaporation the width of the vapour source can be controlled by rotating the electron gun on its plane, thereby scanning an inclined beam over the molten pool. The rotation of gun has further advantages. When multiple strip type electron guns are used for scaling up evaporation length, a dark zone appears between two beams due to physical separation of adjacent guns. This dark zone can be reduced by rotating the gun and thereby bringing two adjacent beams closer. The paper presented here provides the simulation results of the electron beam trajectory and incident power density originating from two strip electron guns by using in-house developed code. The effect of electron gun rotation on the electron beam trajectory and power density is studied. The simulation result is experimentally verified with the image of molten pool and heat affected zone taken after experiment. This technique can be gainfully utilized in controlling the time averaged power density of the electron beam and obtaining quiet evaporation from the metal molten pool.

Mole gun injury.

Science.gov (United States)

Pistré, V; Rezzouk, J

2013-09-01

A mole gun is a weapon, which is used to trap and kill moles. This report provides an overview of the state of knowledge of mole gun injuries, comparable to blast injuries caused by fireworks, explosive or gunshot. Over a 2-year period, the authors reported their experience with ten hand injuries caused by mole gun. Radial side of the hand was often concerned, particularly the thumb. The authors explain their choices in the management of such lesions. Surgery was performed primarily and a large debridement currently seemed to offer the best outcome for the patient. Blast, crush, burns and lacerations may explain the higher rate of amputation to the digits. A long period of physiotherapy, specifically of the hand, was needed before the patient could return to work. This ballistic hand trauma encountered by surgeons requires knowledge and understanding of these injuries. It should be in accordance with firearms law because of severe injuries encountered and possible lethal wounds. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

78 FR 66840 - Revocation of Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns...

Science.gov (United States)

2013-11-07

... Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns Not Intended for Use With Caps AGENCY: Consumer Product Safety Commission. ACTION: Final rule. SUMMARY: Section 106 of the... regulations pertaining to caps intended for use with toy guns refer to obsolete equipment, but the ASTM F963...

Development of coaxial rotating-plasma gun

International Nuclear Information System (INIS)

Ikehata, Takashi; Tanabe, Toshio; Mase, Hiroshi

1985-01-01

A rotating-plasma gun has been devised to produce plasma streams with higher rotational velocities. The working mechanism of the gun and the results of a preliminary experiment have been described. (author)

Plural beam electron gun assembly

International Nuclear Information System (INIS)

Stratton, M.G.

1977-01-01

The invention relates to a cathode ray tube plural-beam-in-line bi-potential electron gun assembly, having applied beam currents of differing levels, manifests structurally modified gun structures to effect focused beam landings at the screen that are evidenced as substantially equi-sized spots thereby providing improved resolution and brightness of the screen imagery. The structural changes embody modifications of the related focusing and accelerator electrodes of the respective guns to provide a partial telescoping arrangement for effecting the discrete placement, forming and shielding of the final focusing lenses. The three lenses so formed are in different planes in partial overlapping axial relationship

Brief use of a specific gun in a violent game does not affect attitudes towards that gun

OpenAIRE

Hilgard, Joseph; Engelhardt, Christopher R.; Bartholow, Bruce D.

2016-01-01

Although much attention has been paid to the question of whether violent video games increase aggressive behaviour, little attention has been paid to how such games might encourage antecedents of gun violence. In this study, we examined how product placement, the attractive in-game presentation of certain real-world firearm brands, might encourage gun ownership, a necessary antecedent of gun violence. We sought to study how the virtual portrayal of a real-world firearm (the Bushmaster AR-15) ...

Gun ownership and firearm-related deaths.

Science.gov (United States)

Bangalore, Sripal; Messerli, Franz H

2013-10-01

A variety of claims about possible associations between gun ownership rates, mental illness burden, and the risk of firearm-related deaths have been put forward. However, systematic data on this issue among various countries remain scant. Our objective was to assess whether the popular notion "guns make a nation safer" has any merits. Data on gun ownership were obtained from the Small Arms Survey, and for firearm-related deaths from a European detailed mortality database (World Health Organization), the National Center for Health Statistics, and others. Crime rate was used as an indicator of safety of the nation and was obtained from the United Nations Surveys of Crime Trends. Age-standardized disability-adjusted life-year rates due to major depressive disorder per 100,000 inhabitants with data obtained from the World Health Organization database were used as a putative indicator for mental illness burden in a given country. Among the 27 developed countries, there was a significant positive correlation between guns per capita per country and the rate of firearm-related deaths (r = 0.80; P ownership and mental illness as independent covariates, gun ownership was a significant predictor (P <.0001) of firearm-related deaths, whereas mental illness was of borderline significance (P = .05) only. The number of guns per capita per country was a strong and independent predictor of firearm-related death in a given country, whereas the predictive power of the mental illness burden was of borderline significance in a multivariable model. Regardless of exact cause and effect, however, the current study debunks the widely quoted hypothesis that guns make a nation safer. Copyright © 2013 Elsevier Inc. All rights reserved.

Ion plasma electron gun

International Nuclear Information System (INIS)

Wakalopulos, G.

1976-01-01

In the disclosed electron gun positive ions generated by a hollow cathode plasma discharge in a first chamber are accelerated through control and shield grids into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam having a distribution adjacent to the cathode emissive surface substantially the same as the distribution of the ion beam impinging upon the cathode. After passing through the grids and the plasma discharge chamber, the electron beam exits from the electron gun via a foil window. Control of the generated electron beam is achieved by applying a relatively low control voltage between the control grid and the electron gun housing (which resides at ground potential) to control the density of the positive ions bombarding the cathode

Recent developments of a two-stage light gas gun for pellet injection

International Nuclear Information System (INIS)

Reggiori, A.

1984-01-01

A report is given on a two-stage pneumatic gun operated with ambient air as first stage driver which has been built and tested. Cylindrical polyethylene pellets of 1 mm diameter and 1 mm length have been launched at velocities up to 1800 m/s, with divergence angles of the pellet trajectory less than 1 0 . It is possible to optimize the pressure pulse for pellets of different masses, simply changing the mass of the piston and/or the initial pressures in the second stage. (author)

SSRL photocathode RF gun test stand

International Nuclear Information System (INIS)

Hernandez, M.; Baltay, M.; Boyce, A.

1995-01-01

A photocathode RF gun test stand designed for the production and study of high brightness electron beams will be constructed at SSRL. The beam will be generated from a laser driven third generation photocathode RF gun being developed in collaboration with BNL, LBL, and UCLA. The 3-5 [MeV] beam from the gun will be accelerated using a SLAC three meter S-band accelerator section, in order to achieve the desired low emittance beam, emittance compensation with solenoidal focusing will be employed

Patterns of gun deaths across US counties 1999-2013.

Science.gov (United States)

Kalesan, Bindu; Galea, Sandro

2017-05-01

We examined the socio-demographic distribution of gun deaths across 3143 counties in 50 United States' states to understand the spatial patterns and correlates of high and low gun deaths. We used aggregate counts of gun deaths and population in all counties from 1999 to 2013 from the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research (WONDER). We characterized four levels of gun violence, as distinct levels of gun death rates of relatively safe, unsafe, violent, and extremely violent counties, based on quartiles of 15-year county-specific gun death rates per 100,000 and used negative binomial regression models allowing clustering by state to calculate incidence rate ratios and 95% confidence intervals (95% CIs). Most states had at least one violent or extremely violent county. Extremely violent gun counties were mostly rural, poor, predominantly minority, had high unemployment rate and homicide rate. Overall, homicide rate was significantly associated with gun deaths (incidence rate ratios = 1.08, 95% CI = 1.06-1.09). In relatively safe counties, this risk was 1.09 (95% CI = 1.05-1.13) and in extremely violent gun counties was 1.03 (95% CI = 1.03-1.04). There are broad differences in gun death rates across the United States representing different levels of gun death rates in each state with distinct socio-demographic profiles. Copyright © 2017 Elsevier Inc. All rights reserved.

18 CFR 157.21 - Pre-filing procedures and review process for LNG terminal facilities and other natural gas...

Science.gov (United States)

2010-04-01

... and review process for LNG terminal facilities and other natural gas facilities prior to filing of... COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER NATURAL GAS ACT APPLICATIONS FOR CERTIFICATES OF PUBLIC... and Approving Abandonment under Section 7 of the Natural Gas Act, as Amended, Concerning Any Operation...

Status and future prospects of SRF gun developments

International Nuclear Information System (INIS)

Teichert, Jochen

2006-01-01

While the concepts of DC and normal-conducting photo-injectors are well proofed, the SRF gun development still possesses a high risk. Challenges are the thermal and contaminant isolation needed between the cathode and superconducting cavity, the choice of the right photocathode and its life time, the difficulty of coupling high-average power into the gun, and beam excitation of higher order cavity modes. But in combination with SRF linacs, the SRF guns are the best solution for high current and CW operation. Thus, several R and D projects of SRF gun have been launched. The talk will give an overview of the history and progress of the SRF gun development. In more detail the technical concept, performance, and status of the Rossendorf superconducting RF gun project, a collaboration of BESSY, DESY, MBI and FZR, will be presented. (author)

Design of a high repetition rate S-band photocathode gun

International Nuclear Information System (INIS)

Han Janghui; Cox, Matthew; Huang, Houcheng; Pande, Shivaji

2011-01-01

Photocathode RF guns have been developed in many laboratories for generating high quality electron beams for free-electron lasers based on linear accelerators. Such guns can generate electron beams with an exceptionally high peak current as well as a small transverse emittance. Their applications have been recently expanded for ultrafast electron diffraction, coherent terahertz radiation, and X-ray or γ-ray radiation by Compton scattering. In this paper, we design an S-band normal-conducting gun with capabilities of high quality beam generation and high repetition rate operation. The RF design and thermal analysis of the gun cavity and coupler are introduced. Optimal position of the gun focusing solenoid for low emittance beam generation is found by performing particle tracking simulations. Then, the gun system is designed to be able to afford the optimal solenoid position. The cooling-water channel surrounding the gun cavity and coupler is designed and analyzed numerically. The pressure in the gun is simulated with a vacuum model containing the detailed inner structure of the gun. An injector for a free-electron laser application is designed by using this gun and the beam dynamics simulation is shown. A cold test with a prototype gun for confirmation of the RF design is reported. - Highlights: → We design an S-band gun for low emittance beam generation and high repetition rate operation. → The RF design and thermal analysis of the gun cavity and coupler are studied. → An FEL injector is designed by using this gun and the beam dynamics simulation is shown. → A cold test with a prototype gun for confirmation of the RF design is reported.

Acute Alcohol Consumption, Alcohol Outlets, and Gun Suicide

Science.gov (United States)

Branas, Charles C.; Richmond, Therese S.; Ten Have, Thomas R.; Wiebe, Douglas J.

2014-01-01

A case–control study of 149 intentionally self-inflicted gun injury cases (including completed gun suicides) and 302 population-based controls was conducted from 2003 to 2006 in a major US city. Two focal independent variables, acute alcohol consumption and alcohol outlet availability, were measured. Conditional logistic regression was adjusted for confounding variables. Gun suicide risk to individuals in areas of high alcohol outlet availability was less than the gun suicide risk they incurred from acute alcohol consumption, especially to excess. This corroborates prior work but also uncovers new information about the relationships between acute alcohol consumption, alcohol outlets, and gun suicide. Study limitations and implications are discussed. PMID:21929327

Separating Batterers and Guns: A Review and Analysis of Gun Removal Laws in 50 States

Science.gov (United States)

Frattaroli, Shannon; Vernick, Jon S.

2006-01-01

Firearms play an important role in lethal domestic violence incidents. The authors review state laws regarding two policies to separate batterers from firearms: laws authorizing police to remove firearms when responding to a domestic violence complaint ("police gun removal laws") and laws authorizing courts to order guns removed from batterers…

Design of an L-band normally conducting RF gun cavity for high peak and average RF power

Energy Technology Data Exchange (ETDEWEB)

Paramonov, V., E-mail: paramono@inr.ru [Institute for Nuclear Research of Russian Academy of Sciences, 60-th October Anniversary prospect 7a, 117312 Moscow (Russian Federation); Philipp, S. [Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Rybakov, I.; Skassyrskaya, A. [Institute for Nuclear Research of Russian Academy of Sciences, 60-th October Anniversary prospect 7a, 117312 Moscow (Russian Federation); Stephan, F. [Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

2017-05-11

To provide high quality electron bunches for linear accelerators used in free electron lasers and particle colliders, RF gun cavities operate with extreme electric fields, resulting in a high pulsed RF power. The main L-band superconducting linacs of such facilities also require a long RF pulse length, resulting in a high average dissipated RF power in the gun cavity. The newly developed cavity based on the proven advantages of the existing DESY RF gun cavities, underwent significant changes. The shape of the cells is optimized to reduce the maximal surface electric field and RF loss power. Furthermore, the cavity is equipped with an RF probe to measure the field amplitude and phase. The elaborated cooling circuit design results in a lower temperature rise on the cavity RF surface and permits higher dissipated RF power. The paper presents the main solutions and results of the cavity design.

Formation of compact toroidal plasmas by magnetized coaxial plasma gun injection into an oblate flux conserver

International Nuclear Information System (INIS)

Turner, W.C.; Goldenbaum, G.C.; Granneman, E.H.A.; Hartman, C.W.; Prono, D.S.; Taska, J.; Smith, A.C. Jr.

1980-01-01

Initial results are reported on the formation of compact toroidal plasmas in an oblate shaped metallic flux conserver. A schematic of the experimental apparatus is shown. The plasma injector is a coaxial plasma gun with solenoid coils wound on the inner and outer electrodes. The electrode length is 100 cm, the diameter of the inner (outer) electrode is 19.3 cm (32.4 cm). Deuterium gas is puffed into the region between electrodes by eight pulsed valves located on the outer electrode 50 cm from the end of the gun. The gun injects into a cylindrically symmetrical copper shell (wall thickness = 1.6 mm) which acts as a flux conserver for the time scale of experiments reported here. The copper shell consists of a transition cylinder 30 cm long, 34 cm in diameter, a cylindrical oblate pill box 40 cm long, 75 cm in diameter and a downstream cylinder 30 cm long, 30 cm in diameter. The gap between the gun and transition cylinder is 6 cm. An axial array of coils outside the vacuum chamber can be used to establish an initial uniform bias field

Study of Control Grid Thermionic Cathode RF Gun

CERN Document Server

Xiao, Jin; Ming, Li; Xinfan, Yang; Xumin, Shen; Yanan, Chen; Zhou, Xu

2004-01-01

In this paper, the beam loading effect of RF Gun was analyzed. To minimize the energy spread, the grid control RF Gun was introduced. The result shows that the grid congrol RF Gun can increase electron beam within 1% energy spread.

Klystron - Space-charge limited flow, guns, Perveance

International Nuclear Information System (INIS)

Isagawa, S.

1999-01-01

This paper treats Thermionic emission, Cathode as an e - emitter, Space-charge limited effect and 3/2 power law, Perveance, Beam spread due to space charge, Pierce guns, Magnetically immersed guns, Method of gun design including simulations, and Examples, mainly treating E3786, which attendees will operate above 1 MW-CW in a practical exercise course at KEK. (author). 74 refs

Gunning for accuracy: Company targets human error with 'foolproof' perforating gun

Energy Technology Data Exchange (ETDEWEB)

Ross, E.

2002-12-01

An innovative new design for a scalloped expandable perforating gun is described. The gun is manufactured in Edmonton by LRI Perforating Systems, and it aimed at reducing the chances of human error that can result in sub-optimal performance. A perforating gun is used to pierce the well's casing to allow hydrocarbons to flow into the wellbore. It consists of a carrier, a pipe with an eighth-inch thick wall that protects the explosives downhole, and an inner tube containing the explosives. The LRI system has a unique interlocking mechanism for the end plates, which are attached to either end of the thin-walled charge holder tube, in addition to other advantageous features, including a price advantage of 10 to 15 per cent. Marketing strategy is designed to interest wi reline companies that focus on vertical well applications. 1 photo.

Analyses in support of risk-informed natural gas vehicle maintenance facility codes and standards :

Energy Technology Data Exchange (ETDEWEB)

Ekoto, Isaac W.; Blaylock, Myra L.; LaFleur, Angela Christine; LaChance, Jeffrey L.; Horne, Douglas B.

2014-03-01

Safety standards development for maintenance facilities of liquid and compressed gas fueled large-scale vehicles is required to ensure proper facility design and operation envelopes. Standard development organizations are utilizing risk-informed concepts to develop natural gas vehicle (NGV) codes and standards so that maintenance facilities meet acceptable risk levels. The present report summarizes Phase I work for existing NGV repair facility code requirements and highlights inconsistencies that need quantitative analysis into their effectiveness. A Hazardous and Operability study was performed to identify key scenarios of interest. Finally, scenario analyses were performed using detailed simulations and modeling to estimate the overpressure hazards from HAZOP defined scenarios. The results from Phase I will be used to identify significant risk contributors at NGV maintenance facilities, and are expected to form the basis for follow-on quantitative risk analysis work to address specific code requirements and identify effective accident prevention and mitigation strategies.

Greenhouse Gas Emissions from Educational Facilities and the EPA Greenhouse Gas Reporting Rule: Actions You Need to Take Now

Science.gov (United States)

Wurmbrand, Mitchell M.; Klotz, Thomas C.

2010-01-01

On September 22, 2009, The United States Environmental Protection Agency (EPA) issued its final rule on greenhouse gas (GHG) emission reporting. The informational literature that EPA has published to support the rule clearly states that EPA believes the vast majority of smaller GHG-emitting facilities, such as educational facilities, will not be…

Characteristics of the ETA gun

International Nuclear Information System (INIS)

Paul, A.C.; Neil, V.K.; Craig, G.D.; Fessenden, T.J.

1981-01-01

The Experimental Test Accelerator (ETA) is a linear induction device consisting of a 2.5-MV electron gun and ten 0.25-MV accelerating units designed to produce a 10-kA beam of electrons at 5 MeV. Calculations with the computer code EBQ as well as experimental measurements indicate that the current produced by the gun is limited by two phenomena. The first arises from the variation of particle energy with time during the pulse. Only particles with energy within a limited range can be transported by the focusing coils in the gun: therefore the variation of the gun's output current with time is determined by the coil settings. The second effect results from a collective interaction at sufficiently large current to cause a virtual cathode to form a few centimeters past the extraction grid. Operation in this regime results in greatly increased beam emittance and poor beam transport through the accelerator. Results of the code calculations are compared with experimental data and found to be in good agreement. (author)

O2 Plasma Etching and Antistatic Gun Surface Modifications for CNT Yarn Microelectrode Improve Sensitivity and Antifouling Properties.

Science.gov (United States)

Yang, Cheng; Wang, Ying; Jacobs, Christopher B; Ivanov, Ilia N; Venton, B Jill

2017-05-16

Carbon nanotube (CNT) based microelectrodes exhibit rapid and selective detection of neurotransmitters. While different fabrication strategies and geometries of CNT microelectrodes have been characterized, relatively little research has investigated ways to selectively enhance their electrochemical properties. In this work, we introduce two simple, reproducible, low-cost, and efficient surface modification methods for carbon nanotube yarn microelectrodes (CNTYMEs): O 2 plasma etching and antistatic gun treatment. O 2 plasma etching was performed by a microwave plasma system with oxygen gas flow and the optimized time for treatment was 1 min. The antistatic gun treatment flows ions by the electrode surface; two triggers of the antistatic gun was the optimized number on the CNTYME surface. Current for dopamine at CNTYMEs increased 3-fold after O 2 plasma etching and 4-fold after antistatic gun treatment. When the two treatments were combined, the current increased 12-fold, showing the two effects are due to independent mechanisms that tune the surface properties. O 2 plasma etching increased the sensitivity due to increased surface oxygen content but did not affect surface roughness while the antistatic gun treatment increased surface roughness but not oxygen content. The effect of tissue fouling on CNT yarns was studied for the first time, and the relatively hydrophilic surface after O 2 plasma etching provided better resistance to fouling than unmodified or antistatic gun treated CNTYMEs. Overall, O 2 plasma etching and antistatic gun treatment improve the sensitivity of CNTYMEs by different mechanisms, providing the possibility to tune the CNTYME surface and enhance sensitivity.

Superconducting augmented rail gun (SARG)

International Nuclear Information System (INIS)

Homan, C.G.; Cummings, C.E.; Fowler, C.M.

1986-01-01

Superconducting augmentation consists of a superconducting coil operating in the persistent mode closely coupled magnetically with a normally conducting rail gun. A theoretical investigation of the effect of this system on a rail gun has shown that two benefits occur. Projectile velocities and launch efficiencies increase significantly depending on the magnetic coupling between the rail and augmentation circuits. Previous work evaluated an idealized system by neglecting energy dissipation effects. In this paper, the authors extend the analysis to include the neglected terms and show improved actual launch efficiencies for the SARG configuration. In this paper, the authors discuss details of projectile design in depth and present preliminary results of rail gun performance

Cerebral damage caused by nail gun injury

DEFF Research Database (Denmark)

Andersen, Chris

2016-01-01

Background Accidents with nail guns are rather common, especially in the construction industry. Most injuries involve the extremities and several present with intracerebral injuries. When the patient is unconscious, it can be a big challenge to determine whether the injury is an accident, self....... The forensic examination showed lesions of intracranial surgery and minor bruises on the arms. No sign of defense injuries was found. There were no signs of malfunction of the nail gun-wielding robot. On the side of the machine, there were a handheld nail gun and the police investigated the case as a possible...... criminal act. They found bloodstains on the back of the machine. When awake, the man explained, that by accident, he had hit his head against a nail gun and as a result of this, the nail gun delivered a nail into his skull. Conclusion Sometimes, the circumstances of a case are not clear...

Geometry Optimization of DC/RF Photoelectron Gun

CERN Document Server

Chen Ping; Yu, David

2005-01-01

Pre-acceleration of photoelectrons in a pulsed, high voltage, short, dc gap and its subsequent injection into an rf gun is a promising method to improve electron beam emittance in rf accelerators. Simulation work has been performed in order to optimize the geometric shapes of a dc/rf gun and improve electron beam properties. Variations were made on cathode and anode shapes, dc gap distance, and inlet shape of the rf cavity. Simulations showed that significant improvement on the normalized emittance (< 1 mm-mrad), compared to a dc gun with flat cathode, could be obtained after the geometric shapes of the gun were optimized.

ATA injector-gun calculations

International Nuclear Information System (INIS)

Paul, A.C.

1981-01-01

ATA is a pulsed, 50 ns 10 KA, 50 MeV linear induction electron accelerator at LLNL. The ETA could be used as an injector for ATA. However the possibility of building a new injector gun for ATA, raised the question as to what changes from the ETA gun in electrode dimensions or potentials, if any, should be considered. In this report the EBQ code results for the four electrode configurations are reviewed and an attempt is made to determine the geometrical scaling laws appropriate to these ETA type gun geometries. Comparison of these scaling laws will be made to ETA operation. The characteristic operating curves for these geometries will also be presented and the effect of washer position determined. It will be shown that emittance growth will impose a limitation on beam current for a given anode potential before the virtual cathode limit is reached

ECR ion source with electron gun

Science.gov (United States)

Xie, Zu Q.; Lyneis, Claude M.

1993-01-01

An Advanced Electron Cyclotron Resonance ion source (10) having an electron gun (52) for introducing electrons into the plasma chamber (18) of the ion source (10). The ion source (10) has a injection enclosure (12) and a plasma chamber tank (14). The plasma chamber (18) is defined by a plurality of longitudinal magnets (16). The electron gun (52) injects electrons axially into the plasma chamber (18) such that ionization within the plasma chamber (18) occurs in the presence of the additional electrons produced by the electron gun (52). The electron gun (52) has a cathode (116) for emitting electrons therefrom which is heated by current supplied from an AC power supply (96) while bias potential is provided by a bias power supply (118). A concentric inner conductor (60) and Outer conductor (62) carry heating current to a carbon chuck (104) and carbon pusher (114) Which hold the cathode (116) in place and also heat the cathode (16). In the Advanced Electron Cyclotron Resonance ion source (10), the electron gun (52) replaces the conventional first stage used in prior art electron cyclotron resonance ion generators.

Revised theory of Pierce-type electron guns

International Nuclear Information System (INIS)

Sar-El, H.Z.

1982-01-01

Attempts to date to obtain the shape of the beam forming electrodes of various Pierce-type electron guns are briefly discussed with emphasis on the many discrepansis in the results of previous works. A revised theory of Pierce-type electron guns is proposed. The shapes of the beam-forming electrodes for all known configurations of Pierce guns were computed on the basis of the proposed theory. (orig.)

Gun Concerns Personal for Duncan

Science.gov (United States)

McNeil, Michele

2013-01-01

As U.S. Secretary of Education Arne Duncan works with other Obama administration officials on policy responses to the shootings at a Connecticut elementary school, he brings a personal and professional history that has acquainted him with the impact of gun violence. As schools chief in Chicago from 2001 to 2008, he was affected by the gun deaths…

Experimental investigation of an optimum configuration for a high-voltage photoemission gun for operation at ≥500  kV

Directory of Open Access Journals (Sweden)

Nobuyuki Nishimori

2014-05-01

Full Text Available We demonstrated the generation of a 500-keV electron beam from a high dc voltage photoemission gun for an energy recovery linac light source [N. Nishimori et al., Appl. Phys. Lett. 102, 234103 (2013]. This demonstration was achieved by addressing two discharge problems that lead to vacuum breakdown in the dc gun. One is field emission generated from a central stem electrode. We employed a segmented insulator to protect the ceramic insulator surface from the field emission. The other is microdischarge at an anode electrode or a vacuum chamber, which is triggered by microparticle transfer or field emission from a cathode electrode. An experimental investigation revealed that a larger acceleration gap, optimized mainly to reduce the surface electric field of the anode electrode, suppresses the microdischarge events that accompany gas desorption. It was also found that nonevaporable getter pumps placed around the acceleration gap greatly help to suppress those microdischarge events. The applied voltage as a function of the total gas desorption is shown to be a good measure for finding the optimum dc gun configuration.

Preliminary design for hot dirty-gas control-valve test facility. Final report

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

This report presents the results of a preliminary design and cost estimating effort for a facility for the testing of control valves in Hot Dirty Gas (HDGCV) service. This design was performed by Mittelhauser Corporation for the United States Department of Energy's Morgantown Energy Technology Center (METC). The objective of this effort was to provide METC with a feasible preliminary design for a test facility which could be used to evaluate valve designs under simulated service conditions and provide a technology data base for DOE and industry. In addition to the actual preliminary design of the test facility, final design/construction/operating schedules and a facility cost estimate were prepared to provide METC sufficient information with which to evaluate this design. The bases, assumptions, and limitations of this study effort are given. The tasks carried out were as follows: METC Facility Review, Environmental Control Study, Gas Generation Study, Metallurgy Review, Safety Review, Facility Process Design, Facility Conceptual Layout, Instrumentation Design, Cost Estimates, and Schedules. The report provides information regarding the methods of approach used in the various tasks involved in the completion of this study. Section 5.0 of this report presents the results of the study effort. The results obtained from the above-defined tasks are described briefly. The turnkey cost of the test facility is estimated to be $9,774,700 in fourth quarter 1979 dollars, and the annual operating cost is estimated to be $960,000 plus utilities costs which are not included because unit costs per utility were not available from METC.

Gun Safety Management with Patients at Risk for Suicide

Science.gov (United States)

Simon, Robert I.

2007-01-01

Guns in the home are associated with a five-fold increase in suicide. All patients at risk for suicide must be asked if guns are available at home or easily accessible elsewhere, or if they have intent to buy or purchase a gun. Gun safety management requires a collaborative team approach including the clinician, patient, and designated person…

A preliminary analysis of floating production storage and offloading facilities with gas liquefaction processes

DEFF Research Database (Denmark)

Nguyen, Tuong-Van; Carranza-Sánchez, Yamid Alberto; Junior, Silvio de Oliveira

2016-01-01

Floating, production, storage and offloading (FPSO) plants are facilities used in upstream petroleum processing. They have gained interest because they are more flexible than conventional plants and can be used for producing oil and gas in deep-water fields. In general, gas export is challenging...... because of the lack of infrastructure in remote locations. The present work investigates the possibility of integrating liquefaction processes on such facilities, considering two mixed-refrigerant and two expansion-based processes suitable for offshore applications. Two FPSO configurations are considered...... in this work, and they were suggested by Brazilian operators for fields processing natural gas with moderate to high content of carbon dioxide. The performance of the combined systems is analysed by conducting energy and exergy analyses. The integration of gas liquefaction results in greater power consumption...

Conceptual design of the test facility for the two-phase critical flow with non-condensable gas

Energy Technology Data Exchange (ETDEWEB)

Chang, Seok Kyu; Chung, Chang Hwan

2000-12-01

The two-phase critical flow test with non-condensible gas is for the simulation of the critical flow phenomena which can be occurred during SB-LOCA on SMART reactor. The requirements of the critical flow test are 7{approx}20mm pipe break dia., 7{approx}12MPa stagnation pressure, 0{approx}60 deg C subcooling degree and 0{approx}0.5kg/s N2 gas flow rate. For the satisfaction of these requirements on the test facility, critical flow rates were calculated with various models. With the selected reference pressure vessel(1.3m{sup 3}), the conceptual design of the test facility was performed. The important components of the test facility are the pressure vessel which has main circulation line, the test section attached to the bottom of the pressure vessel, suppression tank, the N2 gas supply tanks for maintaining the system pressure and N2 gas flow rate at test section and the auxiliary N2 gas converting system. For the measurements of the critical flow rate, flowmeter and level gauge is installed at the upstream of the test section and the pressure vessel, respectively. The realtime pressure control system is installed at the entrance of the pressure vessel for maintaining the system pressure and the N2 gas flow regulating system is also installed at the upstream of the test section. The design of the control and monitoring system for the operation of the test facility and the DAS for acquiring the test data were also performed. The conceptual operating process of the test facility was determined.

Conceptual design of the test facility for the two-phase critical flow with non-condensable gas

International Nuclear Information System (INIS)

Chang, Seok Kyu; Chung, Chang Hwan

2000-12-01

The two-phase critical flow test with non-condensible gas is for the simulation of the critical flow phenomena which can be occurred during SB-LOCA on SMART reactor. The requirements of the critical flow test are 7∼20mm pipe break dia., 7∼12MPa stagnation pressure, 0∼60 deg C subcooling degree and 0∼0.5kg/s N2 gas flow rate. For the satisfaction of these requirements on the test facility, critical flow rates were calculated with various models. With the selected reference pressure vessel(1.3m 3 ), the conceptual design of the test facility was performed. The important components of the test facility are the pressure vessel which has main circulation line, the test section attached to the bottom of the pressure vessel, suppression tank, the N2 gas supply tanks for maintaining the system pressure and N2 gas flow rate at test section and the auxiliary N2 gas converting system. For the measurements of the critical flow rate, flowmeter and level gauge is installed at the upstream of the test section and the pressure vessel, respectively. The realtime pressure control system is installed at the entrance of the pressure vessel for maintaining the system pressure and the N2 gas flow regulating system is also installed at the upstream of the test section. The design of the control and monitoring system for the operation of the test facility and the DAS for acquiring the test data were also performed. The conceptual operating process of the test facility was determined

Natural gas facility methane emissions: measurements by tracer flux ratio in two US natural gas producing basins

Directory of Open Access Journals (Sweden)

Tara I. Yacovitch

2017-11-01

Full Text Available Methane (CH4 emission rates from a sample of natural gas facilities across industry sectors were quantified using the dual tracer flux ratio methodology. Measurements were conducted in study areas within the Fayetteville shale play, Arkansas (FV, Sept–Oct 2015, 53 facilities, and the Denver-Julesburg basin, Colorado, (DJ, Nov 2014, 21 facilities. Distributions of methane emission rates at facilities by type are computed and statistically compared with results that cover broader geographic regions in the US (Allen et al., 2013, Mitchell et al., 2015. DJ gathering station emission rates (kg CH4 hr–1 are lower, while FV gathering and production sites are statistically indistinguishable as compared to these multi-basin results. However, FV gathering station throughput-normalized emissions are statistically lower than multi-basin results (0.19% vs. 0.44%. This implies that the FV gathering sector is emitting less per unit of gas throughput than would be expected from the multi-basin distribution alone. The most common emission rate (i.e. mode of the distribution for facilities in this study is 40 kg CH4 hr–1 for FV gathering stations, 1.0 kg CH4 hr–1 for FV production pads, and 11 kg CH4 hr–1 for DJ gathering stations. The importance of study design is discussed, including the benefits of site access and data sharing with industry and of a scientist dedicated to measurement coordination and site choice under evolving wind conditions.

Gas detection for alternate-fuel vehicle facilities.

Science.gov (United States)

Ferree, Steve

2003-05-01

Alternative fuel vehicles' safety is driven by local, state, and federal regulations in which fleet owners in key metropolitan [table: see text] areas convert much of their fleet to cleaner-burning fuels. Various alternative fuels are available to meet this requirement, each with its own advantages and requirements. This conversion to alternative fuels leads to special requirements for safety monitoring in the maintenance facilities and refueling stations. A comprehensive gas and flame monitoring system needs to meet the needs of both the user and the local fire marshal.

High-Energy Gun-Injected Toroidal Quadrupole

International Nuclear Information System (INIS)

Hammel, J.E.; Henins, I.; Kewish, R.W. Jr.; Marshall, J.; Sherwood, A.R.

1971-01-01

A quadrupole device is being used to investigate the trapping and containment of an energetic gun plasma. The quadrupole is designed to contain a peak density of 5 x 10 13 cm -3 at 2.5 keV within the MHD-stable region. At design field there are 5 gyro-radii for 2. 5-keV protons from the separatrix to the ψ crit . The interior conductors are directly driven with a 0.8-MJ capacitor bank. The current to the coils is fed through a single pair of dipole-guarded conductors to each coil. The coils are also supported from the current feed, The dipole guard is in a force-free configuration with 5 gyro-radii for 2. 5-keV protons from the separatrix (between the dipole and quadrupole fields) to the dipole surface. The dipole is designed so that loss of plasma from the dipole region will be directed away from the interior conductors. This feature is necessary for the prevention of contamination by secondary gas produced by plasma lost at the dipole guard. Experiments at one-half design value of magnetic field have shown that the kilovolt energy gun plasma is trapped by depolarization currents around the coils, and that a very high percentage (>50%) of the gun output can be trapped. The plasma density is measured by a unique Michelson interferometer using CO 2 laser light. The energy of the plasma is derived from magnetic pickup loops placed outside the containment region. The leak caused by the dipole guard Held has been examined by double electric probe measurements. The plasma drift thus inferred is an order of magnitude less than that predicted by a model of Meade's or by calculations by us. This casts doubt upon the validity of any such simple model and emphasizes the necessity of further experimental investigation of the matter. New coils which are being built to operate at full design magnetic field strength will allow a check on the containment time of the device for kilovolt energy plasma. (author)

Performance of a carbon nanotube field emission electron gun

Science.gov (United States)

Getty, Stephanie A.; King, Todd T.; Bis, Rachael A.; Jones, Hollis H.; Herrero, Federico; Lynch, Bernard A.; Roman, Patrick; Mahaffy, Paul

2007-04-01

A cold cathode field emission electron gun (e-gun) based on a patterned carbon nanotube (CNT) film has been fabricated for use in a miniaturized reflectron time-of-flight mass spectrometer (RTOF MS), with future applications in other charged particle spectrometers, and performance of the CNT e-gun has been evaluated. A thermionic electron gun has also been fabricated and evaluated in parallel and its performance is used as a benchmark in the evaluation of our CNT e-gun. Implications for future improvements and integration into the RTOF MS are discussed.

Law Enforcement and Gun Retailers as Partners for Safely Storing Guns to Prevent Suicide: A Study in 8 Mountain West States.

Science.gov (United States)

Runyan, Carol W; Brooks-Russell, Ashley; Brandspigel, Sara; Betz, Marian; Tung, Gregory; Novins, Douglas; Agans, Robert

2017-11-01

To examine the extent to which law enforcement agencies (LEAs) and gun retailers are willing to offer voluntary, temporary storage as a part of an overall suicide prevention effort. We invited all LEAs and gun retailers in 8 US states to respond to questionnaires asking about their willingness to offer temporary gun storage and their recommendations to gun owners about safe storage. We collected data in 2016 from 448 LEAs and 95 retailers (response rates of 53% and 25%, respectively). Three quarters of LEAs (74.8%; 95% confidence interval [CI] = 72.1, 77.5) indicated they already provided temporary storage compared with 47.6% (95% CI = 39.2, 56.0) of retailers. LEAs were most willing to provide storage when a gun owner was concerned about the mental health of a family member. Retailers were more receptive than were LEAs to providing storage when visitors were coming or for people wanting storage while traveling. Both groups recommended locking devices within the home, but LEAs were slightly more favorable to storing guns away from the home. Law enforcement agencies and gun retailers are important resources for families concerned about suicide.

The Influence of the Axial Magnetic Field Upon- the Coaxial Plasma Gun Parameters

International Nuclear Information System (INIS)

El-Aragi, G.M.; El-Demardash, A.

2001-01-01

This study concerns with the influence of an applied axial magnetic field upon the electrical parameters and on the brightness (luminance) of argon plasma. The brightness was measured by with a photomultiplier type of IP28 RCA. The experimental results are investigated with plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied. It was found that the thickness of skin-layer δ about 0.01 cm and the wavelength λ, of the perturbation about 1.3 cm i.e. the instability has been satisfied. The growth rate γ of the instability about 10 6 sec -1 . (author)

Trapping of gun-injected plasma by a tokamak

International Nuclear Information System (INIS)

Leonard, A.W.; Dexter, R.N.; Sprott, J.C.

1986-01-01

It is shown that a plasma produced by a Marshall gun can be injected into and trapped by a tokamak plasma. Gun injection raises the line-averaged density and peaks the density profile. Trapping of the gun-injected plasma is explainable in terms of a depolarization current mechanism

High Brightness Injectors Based On Photocathode DC Gun

International Nuclear Information System (INIS)

B. Yunn

2001-01-01

Sample results of new injector design method based on a photocathode dc gun are presented, based on other work analytically proving the validity of the emittance compensation scheme for the case even when beam bunching is involved. We have designed several new injectors appropriate for different bunch charge ranges accordingly. Excellent beam quality produced by these injectors clearly shows that a photocathode dc gun can compete with a rf gun on an equal footing as the source of an electron beam for the bunch charge ranging up to 2 nano Coulomb (nC). This work therefore elevates a dc gun based injector to the preferred choice for many ongoing high brightness accelerator projects considering the proven operational stability and high average power capability of the dc gun

What is the level of household gun ownership in urban Mexico? An estimate from the first Mexican survey on gun ownership 2017.

Science.gov (United States)

Perez Esparza, David; Hemenway, David

2017-12-20

Gun violence has increased in Mexico since the mid-2000s, but little is known about patterns of gun ownership. We examine the size and composition of the privately held urban firearm stock in Mexico, motivations for ownership, and attitudes about gun laws. To this end, a household telephone survey of 1361 adults living in nine Mexican cities was conducted in the summer of 2017. We find that few urban Mexican households contain guns. Most of those who report ownership possess one gun, having purchased it recently for self-defense. Few urban Mexican citizens plan to purchase a gun in the future. Respondents are more likely to believe that crime in Mexico would increase if guns were allowed in more places (ie, workplaces and motor vehicles). Evidence suggests urban Mexico has relative low rates of firearm ownership. Few city dwellers plan on obtaining a firearm in the near future. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Electrothermal plasma gun as a pellet injector

International Nuclear Information System (INIS)

Kincaid, R.W.; Bourham, M.A.

1994-01-01

The NCSU electrothermal plasma gun SIRENS has been used to accelerate plastic (Lexan polycarbonate) pellets, to determine the feasibility of the use of electrothermal guns as pellet injectors. The use of an electrothermal gun to inject frozen hydrogenic pellets requires a mechanism to provide protective shells (sabots) for shielding the pellet from ablation during acceleration into and through the barrel of the gun. The gun has been modified to accommodate acceleration of the plastic pellets using special acceleration barrels equipped with diagnostics for velocity and position of the pellet, and targets to absorb the pellet's energy on impact. The length of the acceleration path could be varied between 15 and 45 cm. The discharge energy of the electrothermal gun ranged from 2 to 6 kJ. The pellet velocities have been measured via a set of break wires. Pellet masses were varied between 0.5 and 1.0 grams. Preliminary results on 0.5 and 1.0 g pellets show that the exit velocity reaches 0.9 km/s at 6 kJ input energy to the source. Higher velocities of 1.5 and 2.7 km/s have been achieved using 0.5 and 1.0 gm pellets in 30 cm long barrel, without cleaning the barrel between the shots

78 FR 11902 - Review of Gun Safety Technologies

Science.gov (United States)

2013-02-20

... DEPARTMENT OF JUSTICE Office of Justice Programs [OJP (NIJ) Docket No. 1615] Review of Gun Safety...'s Plan to reduce gun violence released on January 16, 2013, the U.S. Department of Justice, Office... emerging gun safety technologies and plans to issue a report on the availability and use of those...

Gun Access and Safety Practices among Older Adults

Directory of Open Access Journals (Sweden)

Hillary D. Lum

2016-01-01

Full Text Available Background. Given high rates of gun ownership among older adults, geriatric providers can assess firearm safety practices using a “5 Ls” approach: Locked; Loaded; Little children; feeling Low; and Learned owner. This study describes gun access and the “5 Ls” among US older adults. Methods. Data on the “5 Ls” from the Second Injury Control and Risk Survey (ICARIS-2, a national telephone survey conducted by the Centers for Disease Control and Prevention, were analyzed. Weighted variables were used to generate national estimates regarding prevalence of gun ownership and associated gun safety among older adults (≥55 years. Results. Of 2939 older adults, 39% (95% CI 37%–42% reported ≥1 gun stored at home. Among those with guns at home, 21% (95% CI 18–24% stored guns loaded and unlocked; 9.2% (95% CI 6.6–12% had ≥1 child in household; 5.1% (95% CI 3.5–6.8% reported past-year suicidal ideation and 3.6% (95% CI 2.1–5.2% reported history of a suicide attempt; and 55% (95% CI 51–59% stated that ≥1 adult had attended firearm safety workshop. Conclusion. Some older adults may be at elevated risk of firearm injury because of storage practices, suicidal thoughts, or limited safety training. Future work should assess effective approaches to reduce the risk of gun-related injuries among older adults.

Utility of indices of gun availability in the community.

Science.gov (United States)

Shenassa, Edmond D; Daskalakis, Constantine; Buka, Stephen L

2006-01-01

To estimate the degree to which the proportion of homicides and suicides committed with a gun is associated with reported availability of firearms across Chicago neighbourhoods. Data were collected as part of the Project on Human Development in Chicago Neighborhoods (PHDCN), a combined neighbourhood and individual level study of the city of Chicago. The study used data from 837 PHDCN participants between the ages of 17 and 22, residing in 170 different neighbourhoods. Gun availability was measured via participant reports on whether they had carried a gun and whether they perceived gun access to be easy in their community. Data on suicides and homicides were obtained from the Chicago Department of Health. A 10% change in the proportion of homicides committed by a gun in a neighbourhood was associated with a 20% increase in both the odds of reported gun access and reported gun carrying (p=0.002 and 0.048, respectively). The proportion of firearm related suicides was not associated with either of those self reported measures. The proportion of firearm related homicides, but not the proportion of firearm related suicides, is a useful predictor of gun availability across small areas such as neighbourhoods.

Application of Coaxial Ion Gun for Film Generation and Ion Implantation

Science.gov (United States)

Takatsu, Mikio; Asai, Tomohiko; Kurumi, Satoshi; Suzuki, Kaoru; Hirose, Hideharu; Masutani, Shigeyuki

A magnetized coaxial plasma gun (MCPG) is here utilized for deposition on high-melting-point metals. MCPGs have hitherto been studied mostly in the context of nuclear fusion research, for particle and magnetic helicity injection and spheromak formation. During spheromak formation, the electrode materials are ionized and mixed into the plasmoid. In this study, this ablation process by gun-current sputtering is enhanced for metallic thin-film generation. In the proposed system geometry, only ionized materials are electromagnetically accelerated by the self-Lorentz force, with ionized operating gas as a magnetized thermal plasmoid, contributing to the thin-film deposition. This reduces the impurity and non-uniformity of the deposited thin-film. Furthermore, as the ions are accelerated in a parallel direction to the injection axis, vertical implantation of the ions into the substrate surface is achieved. To test a potential application of the developed system, experiments were conducted involving the formation of a buffer layer on hard ceramics, for use in dental materials.

Low Emittance Guns for the ILC Polarized Electron Beam

International Nuclear Information System (INIS)

Clendenin, J. E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R. E.; Maruyama, T.; Miller, R. H.; Wang, J. W.; Zhou, F.

2007-01-01

Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of ≥200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while ≥500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

Low Emittance Guns for the ILC Polarized Electron Beam

International Nuclear Information System (INIS)

Clendenin, J.E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.H.; Wang, J.W.; Zhou, F.; SLAC

2006-01-01

Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of (ge)200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while (ge)500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

Advances in DC photocathode electron guns

International Nuclear Information System (INIS)

Dunham M, Bruce; Heartmann, P.; Reza Kazimi; Hongxiu Liu; Poelker, B.M.; Price, J.S.; Rutt, P.M.; Schneider, W.J.; Sinclair K, Charles

1998-01-01

At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughout. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion back-bombardment, and precise control of all of the electrons emitted from the cathode. In this paper, the authors will review recent results and discuss implications for future photocathode guns

Advances in DC photocathode electron guns

International Nuclear Information System (INIS)

Dunham, B. M.; Hartmann, P.; Kazimi, R.; Liu, H.; Poelker, B. M.; Price, J. S.; Rutt, P. M.; Schneider, W. J.; Sinclair, C. K.

1999-01-01

At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughput. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion backbombardment, and precise control of all of the electrons emitted from the cathode. In this paper, we will review recent results and discuss implications for future photocathode guns

A compact electron gun using field emitter array

International Nuclear Information System (INIS)

Asakawa, M.R.; Ikeda, A.; Miyabe, N.; Yamaguchi, S.; Kusaba, M.; Tsunawaki, Y.

2008-01-01

A compact electron gun using field emitter array has been developed. With a simple triode configuration consisting of FEA, mid-electrode and anode electrode, the electron gun produces a parallel beam with a diameter of 0.5 mm. This electron gun is applicable for compact radiation sources such as Cherenkov free-electron lasers

Characterisation of 100 kW electron beam melting gun and its adaptation as electron gun for high power DC electron accelerators

International Nuclear Information System (INIS)

Banerjee, Srutarshi; Bhattacharjee, Dhruva; Waghmare, Abhay; Tiwari, Rajnish; Bakhtsingh, R.I.; Dasgupta, K.; Gupta, Sachin; Prakash, Baibhaw; Jha, M.N.

2015-01-01

The paper deals with the characterization of the 100 kW electron beam melting gun for its adaptation in high power DC Electron Accelerators. The indigenously designed electron beam melting system at BARC is chosen for characterization. It comprises of electron gun as source of electrons, two electromagnetic focusing lenses viz. upper focusing lens and lower focusing lens for beam focusing, intermediate beam aperture for vacuum decoupling between gun region and melt zone, deflection and oscillation lens for maneuvering the beam on the melt charge and water cooled crucible that acts as a beam dump. In this system, the electron gun is designed for 40 kV and 100 kW corresponding to a maximum beam current of 2.5 A. The electron gun uses directly heated spiral tungsten filament. The operating temperature of the filament is 2800 °K. The focusing electrode and the anode profile are designed based on Pierce geometry. High Power DC Electron Accelerators require high currents of 1 A. The beam must comply with the requirement of 40 mm beam diameter and 10 mrad divergence at the exit of the electron gun. The characterization of the existing electron gun was done to find out all the beam parameters, for e.g. beam size, beam divergence, perveance etc. to be adapted or to be modified for the design of electron gun for high power DC accelerators. This paper shows limitations and the possible solutions for design of high power DC accelerators. (author)

Spheromak experiment using separate guns for formation and sustainment

International Nuclear Information System (INIS)

Brown, M.R.; Martin, A.

1996-01-01

An experiment is described that incorporates the use of separate magnetized plasma guns for formation and sustainment of a spheromak. It is shown that energy coupling efficiency approaches unity if the gun and spheromak are of comparable size. A large gun should be able to operate at lower current and therefore lower voltage. In addition, it is expected that a gun matched to the size of the spheromak will cause less perturbation to the equilibrium. It is proposed to use a smaller gun for spheromak formation and a large, efficient gun for sustainment. The theoretical basis for the experiment is developed, and the details of the experiment are described. A prediction of the equilibrium magnetic flux surfaces using the EFIT code is presented. 28 refs., 3 figs., 1 tab

Recent advances in high-brightness electron guns at AES

International Nuclear Information System (INIS)

Bluem, H.; Todd, A.M.M.; Cole, M.D.; Rathke, J.; Schultheiss, T.

2003-01-01

We describe a number of active Advanced Energy Systems projects pertaining to the development of advanced, high-brightness electron guns for various applications. These projects include a fully superconducting, CW RF gun, nearing test, that utilizes the niobium surface as the photocathode material. An integrated 100 mA, low emittance DC/SRF gun, ideal as an injector for ERL-type light sources and intended as the injector for a 100 kW FEL, is in late design stage. A parallel high-power, CW, normal-conducting L-band RF gun project has just begun. The early performance analysis for this gun also shows good promise as an injector for ERL-type light sources. Lastly, a fully axisymmetric RF gun, operating in X-band, is being studied as a source of extremely bright electron bunches

Stereotactic breast biopsy with a biopsy gun

International Nuclear Information System (INIS)

Parker, S.H.; Lovin, J.; Luethke, J.; Jobe, W.E.; Hopper, K.D.; Yakes, W.F.

1989-01-01

With the recent introduction of stereotactic mammographic localizing devices, the authors have been performing histologic core needle breast biopsies in which the Bard biopsy gun is used in conjunction with sterotactic guidance. The authors have performed 60 breast gun biopsies with 16-gauge and 18-gauge biopsy-cut needles. These biopsies were followed immediately by traditional surgical excision. Pathologic results correlated well in 52 of the 60 patients, including 10 of 13 cancers. Three of the eight negative correlations occurred when diagnosis was made on gun biopsy but not on surgical biopsy. The stereotactic- guided gun biopsies appear to approach the surgical gold standard, decrease patient discomfort and potential disfigurement, lower the cost of breast biopsy, and lower the threshold necessary to perform breast biopsy

RF Electron Gun with Driven Plasma Cathode

CERN Document Server

Khodak, Igor

2005-01-01

It's known that RF guns with plasma cathodes based on solid-state dielectrics are able to generate an intense electron beam. In this paper we describe results of experimental investigation of the single cavity S-band RF gun with driven plasma cathode. The experimental sample of the cathode based on ferroelectric ceramics has been designed. Special design of the cathode permits to separate spatially processes of plasma development and electron acceleration. It has been obtained at RF gun output electron beam with particle energy ~500 keV, pulse current of 4 A and pulse duration of 80 ns. Results of experimental study of beam parameters are referred in. The gun is purposed to be applied as the intense electron beam source for electron linacs.

College Students Opinions on Gun Violence.

Science.gov (United States)

Lewis, Rhonda K; LoCurto, Jamie; Brown, Kyrah; Stowell, David; Maryman, J'Vonnah; Dean, Amber; McNair, Thoi; Ojeda, Debbie; Siwierka, Julia

2016-06-01

Gun violence and control issues have become serious public health problems. This study gathered the opinions from 419 college students from a Midwestern University. Participants were asked about beliefs about purchasing assault weapons, beliefs about bringing handguns to college campuses and beliefs about contributing factors that lead to gun violence. Participants completed surveys online. The findings showed that overall 54 % of respondents believed that military assault weapons should be banned and 53 % agree that teachers should be allowed to carry a registered handgun on campus. There were statistically significant differences between males and females on these issues. For instance, females believed military assault weapons and high capacity magazines should be banned more than 1.9 times (p = .004) p gun violence were decline in parenting and family values (17 %), gang involvement (14 %), bullying (13.8 %) and guns being easy to obtain (13.8 %). Limitations and implications for policy work are discussed.

Injector design for liner-on-target gas-puff experiments

Science.gov (United States)

Valenzuela, J. C.; Krasheninnikov, I.; Conti, F.; Wessel, F.; Fadeev, V.; Narkis, J.; Ross, M. P.; Rahman, H. U.; Ruskov, E.; Beg, F. N.

2017-11-01

We present the design of a gas-puff injector for liner-on-target experiments. The injector is composed of an annular high atomic number (e.g., Ar and Kr) gas and an on-axis plasma gun that delivers an ionized deuterium target. The annular supersonic nozzle injector has been studied using Computational Fluid Dynamics (CFD) simulations to produce a highly collimated (M > 5), ˜1 cm radius gas profile that satisfies the theoretical requirement for best performance on ˜1-MA current generators. The CFD simulations allowed us to study output density profiles as a function of the nozzle shape, gas pressure, and gas composition. We have performed line-integrated density measurements using a continuous wave (CW) He-Ne laser to characterize the liner gas density. The measurements agree well with the CFD values. We have used a simple snowplow model to study the plasma sheath acceleration in a coaxial plasma gun to help us properly design the target injector.

rf traveling-wave electron gun for photoinjectors

Science.gov (United States)

Schaer, Mattia; Citterio, Alessandro; Craievich, Paolo; Reiche, Sven; Stingelin, Lukas; Zennaro, Riccardo

2016-07-01

The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL) machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least) double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.

A tapered multi-gap multi-aperture pseudospark-sourced electron gun based X-band slow wave oscillator

Science.gov (United States)

Kumar, N.; Lamba, R. P.; Hossain, A. M.; Pal, U. N.; Phelps, A. D. R.; Prakash, R.

2017-11-01

The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ˜71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115-190 A/cm2 at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10-11.7 GHz with a peak power of ˜10 kW for ˜50 ns.

Strong gun laws are not enough: the need for improved enforcement of secondhand gun transfer laws in Massachusetts.

Science.gov (United States)

Braga, Anthony A; Hureau, David M

2015-10-01

Research suggests that an overwhelming majority of crime guns were transferred by private sellers before recovery by law enforcement. Unfortunately, most states do not regulate these transactions. This study examines whether analyses of state-level private transfer data could be used to develop interventions to reduce the supply of handguns to violent criminals. Traced Boston crime handguns first sold at Massachusetts license dealers were matched to state secondhand gun transfer data. Logistic regression and descriptive statistics were used to analyze the characteristics of recovered crime guns and in-state primary and secondary market transaction patterns. For crime handguns with records of secondary market transactions in Massachusetts, many rapidly move from private transfer to recovery by the police. Unfortunately, important transaction data on the in-state sources of nearly 63% of recovered handguns were not readily available to law enforcement agencies. Data on private transfers of guns could be used to prevent violent injuries by reducing criminal access. However, the passage of strong private transfer gun laws needs to be accompanied by investments in the vigorous enforcement of reporting requirements. Copyright © 2015 Elsevier Inc. All rights reserved.

Gun Carrying by High School Students in Boston, MA: Does Overestimation of Peer Gun Carrying Matter?

Science.gov (United States)

Hemenway, David; Vriniotis, Mary; Johnson, Renee M.; Miller, Matthew; Azrael, Deborah

2011-01-01

This paper investigates: (1) whether high school students overestimate gun carrying by their peers, and (2) whether those students who overestimate peer gun carrying are more likely to carry firearms. Data come from a randomly sampled survey conducted in 2008 of over 1700 high school students in Boston, MA. Over 5% of students reported carrying a…

Advances in DC photocathode electron guns

International Nuclear Information System (INIS)

Dunham, B.M.; Hartmann, P.; Kazimi, R.; Liu, H.; Poelker, B.M.; Price, J.S.; Rutt, P.M.; Schneider, W.J.; Sinclair, C.K.

1999-01-01

At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughput. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion backbombardment, and precise control of all of the electrons emitted from the cathode. In this paper, we will review recent results and discuss implications for future photocathode guns. copyright 1999 American Institute of Physics

The polarized electron gun for the SLC

International Nuclear Information System (INIS)

Schultz, D.C.; Clendenin, J.; Frisch, J.; Hoyt, E.; Klaisner, L.; Woods, M.; Wright, D.; Zolotorev, M.

1992-03-01

A new polarized electron gun for use on the SLC at SLAC has been built and tested. It is a diode gun with a laser driven GaAs photocathode. It is designed to provide short (2ns) pulses of 10 A at 160 kV at 120 Hz. The design features of the gun and results from a testing program on a new and dedicated beam line are presented. Early results from operation on the SLC will also be shown

Gas cooled fast reactor background, facilities, industries and programmes

International Nuclear Information System (INIS)

Dalle Donne, M.

1980-05-01

This report was prepared at the request of the OECD-NEA Coordinating Group on Gas Cooled Fast Reactor Development and it represents a contribution (Vol.II) to the jointly sponsored Vol.I (GCFR Status Report). After a chapter on background with a brief description of the early studies and the activities in the various countries involved in the collaborative programme (Austria, Belgium, France, Germany, Japan, Sweden, Switzerland, United Kingdom and United States), the report describes the facilities available in those countries and at the Gas Breeder Reactor Association and the industrial capabilities relevant to the GCFR. Finally the programmes are described briefly with programme charts, conclusions and recommendations are given. (orig.) [de

Gas-filled hohlraum experiments at the National Ignition Facility

International Nuclear Information System (INIS)

Fernandez, Juan C.; Goldman, S.R.; Kline, J.L.; Dodd, E.S.; Gautier, C.; Grim, G.P.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.; Schmidt, D.W.; Workman, J.B.; Braun, D.G.; Dewald, E.L.; Landen, O.L.; Campbell, K.M.; Holder, J.P.; MacKinnon, A.J.; Niemann, C.; Schein, J.

2006-01-01

Experiments done at the National Ignition Facility laser [J. A. Paisner, E. M. Campbell, and W. Hogan, Fusion Technol. 26, 755 (1994)] using gas-filled hohlraums demonstrate a key ignition design feature, i.e., using plasma pressure from a gas fill to tamp the hohlraum-wall expansion for the duration of the laser pulse. Moreover, our understanding of hohlraum energetics and the ability to predict the hohlraum soft-x-ray drive has been validated in ignition-relevant conditions. Finally, the laser reflectivity from stimulated Raman scattering in the fill plasma, a key threat to hohlraum performance, is shown to be suppressed by choosing a design with a sufficiently high ratio of electron temperature to density

Numerical modeling of deflagration mode in coaxial plasma guns

Science.gov (United States)

Sitaraman, Hariswaran; Raja, Laxminarayan

2012-10-01

Pulsed coaxial plasma guns have been used in several applications in the field of space propulsion, nuclear fusion and materials processing. These devices operate in two modes based on the delay between gas injection and breakdown initiation. Larger delay led to the plasma detonation mode where a compression wave in the form of a luminous front propagates from the breech to the muzzle. Shorter delay led to the more efficient deflagration mode characterized by a relatively diffuse plasma with higher resistivity. The overall physics of the discharge in the two modes of operation and in particular the latter remain relatively unexplored. Here we perform a computational modeling study by solving the non-ideal Magneto-hydrodynamics equations for the quasi-neutral plasma in the coaxial plasma gun. A finite volume formulation on an unstructured mesh framework with an implicit scheme is used to do stable computations. The final work will present details of important species in the plasma, particle energies and Mach number at the muzzle. A comparison of the plasma parameters will be made with the experiments reported in ref. [1]. [4pt] [1] F. R. Poehlmann et al., Phys. Plasmas 17, 123508 (2010)

Tri-Service Green Gun Barrel (PP 1074)

National Research Council Canada - National Science Library

Rusch, Lawrence F

2003-01-01

...) PP 1074 Tri-Service Green Gun Barrel. The program's goal was to develop an environmentally friendly process for depositing wear and erosion resistant materials onto gun bores replacing the current hazardous aqueous electro-deposition...

Progress on a cryogenically cooled RF gun polarized electron source

Energy Technology Data Exchange (ETDEWEB)

Fliller, R.P., III; Edwards, H.; /Fermilab

2006-08-01

RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.

Emittance studies of the BNL/SLAC/UCLA 1.6 cell photocathode rf gun

International Nuclear Information System (INIS)

Palmer, D.T.; Miller, R.H.; Wang, X.J.

1997-01-01

The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 micros. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, ε o , of the copper cathode has been measured

The design of gridded pierce guns for accelerators

International Nuclear Information System (INIS)

True, R.

1985-01-01

It is vital to employ ultra-laminar beams in electron linacs to maximize charge transport to the target. This paper presents numerical and experimental design techniques which have led to significant improvements in gridded Pierce guns used in microwave tubes and electron linacs. The paper concludes with two gun/injector concepts which have demonstrated enhanced performance over standard triode Pierce guns

A high-compression electron gun for C6+ production: concept, simulations and mechanical design

Science.gov (United States)

Mertzig, Robert; Breitenfeldt, M.; Mathot, S.; Pitters, J.; Shornikov, A.; Wenander, F.

2017-07-01

In this paper we report on simulations and the mechanical design of a high-compression electron gun for an Electron Beam Ion Source (EBIS) dedicated for production of high intensity and high repetition rate pulses of bare carbon ions for injection into linac-based hadron therapy facilities. The gun is presently under construction at CERN to be retrofitted into the TwinEBIS test bench for experimental studies. We describe the design constraints, show results of numeric simulations and report on the mechanical design featuring several novel ideas. The reported design makes use of combined-function units with reduced number of mechanical joints that were carefully controlled and tuned during the manufacturing phase. The simulations addressed a wide range of topics including the influence of thermal effects, focusing optics, symmetry-breaking misalignments and injection into a full 5 T field.

Therminoic gun control system for the CEBAF injector

International Nuclear Information System (INIS)

Pico, R.; Diamond, B.; Fugitt, J.; Bork, R.

1989-01-01

The injector for the CEBAF accelerator must produce a high-quality electron beam to meet the overall accelerator specifications. A Hermosa electron gun with a 2 mm-diameter cathode and a control aperture has been chosen as the electron source. This must be controlled over a wide range of operating conditions to meet the beam specifications and to provide flexibility for accelerator commissioning. The gun is controlled using Computer Automated Measurement and Control (CAMAC IEEE-583) technology. The system employs the CAMAC-based control architecture developed at CEBAF. The control system has been tested, and early operating data on the electron gun and the injector beam transport system has been obtained. This system also allows gun parameters to be stored at the operator location, without paralyzing operation. This paper describes the use of this computer system in the control of the CEBAF electron gun. 2 refs., 6 figs., 1 tab

An rf modulated electron gun pulser for linacs

International Nuclear Information System (INIS)

Legg, R.; Hartline, R.

1991-01-01

Present linac injector designs often make use of sub-harmonic prebuncher cavities to properly bunch the electron beam before injection into a buncher and subsequent accelerating cavities. This paper proposes an rf modulated thermionic gun which would allow the sub-harmonic buncher to be eliminated from the injector. The performance parameters for the proposed gun are 120 kV operating voltage, macropulse duration-single pulse mode 2 nsec, multiple pulse mode 100 nsec, rf modularing frequency 500 MHz, charge per micropulse 0.4 nC, macropulse repetition frequency 10 Hz (max). The gun pulser uses a grid modulated planar triode to drive the gun cathode. The grid driver takes advantage of recently developed modular CATV rf drivers, high performance solid state pulser devices, and high-frequency fiber optic transmitters for telecommunications. Design details are presented with associated SPICE runs simulating operation of the gun

Gun violence in Americans' social network during their lifetime.

Science.gov (United States)

Kalesan, Bindu; Weinberg, Janice; Galea, Sandro

2016-12-01

The overall burden of gun violence death and injury in the US is now well understood. However, no study has shown the extent to which gun violence is associated with the individual lives of Americans. We used fatal and non-fatal gun injury rates in 2013 from Centers for Disease Control and Prevention's Web-based Injury Statistics Query and Reporting System (WISQARS) and generally accepted estimates about the size of an American's social network to determine the likelihood that any given person will know someone in their personal social network who is a victim of gun violence during their lifetime. We derived estimates in the overall population and among racial/ethnic groups and by gun-injury intent. The likelihood of knowing a gun violence victim within any given personal network over a lifetime is 99.85% (99.8% to 99.9%). The likelihood among non-Hispanic white, black, Hispanic and other race Americans were 97.1%, 99.9%, 99.5% and 88.9% respectively. Nearly all Americans of all racial/ethnic groups are likely to know a victim of gun violence in their social network during their lifetime. Copyright © 2016 Elsevier Inc. All rights reserved.

Dark current studies on a normal-conducting high-brightness very-high-frequency electron gun operating in continuous wave mode

Directory of Open Access Journals (Sweden)

R. Huang

2015-01-01

Full Text Available We report on measurements and analysis of a field-emitted electron current in the very-high-frequency (VHF gun, a room temperature rf gun operating at high field and continuous wave (CW mode at the Lawrence Berkeley National Laboratory (LBNL. The VHF gun is the core of the Advanced Photo-injector Experiment (APEX at LBNL, geared toward the development of an injector for driving the next generation of high average power x-ray free electron lasers. High accelerating fields at the cathode are necessary for the high-brightness performance of an electron gun. When coupled with CW operation, such fields can generate a significant amount of field-emitted electrons that can be transported downstream the accelerator forming the so-called “dark current.” Elevated levels of a dark current can cause radiation damage, increase the heat load in the downstream cryogenic systems, and ultimately limit the overall performance and reliability of the facility. We performed systematic measurements that allowed us to characterize the field emission from the VHF gun, determine the location of the main emitters, and define an effective strategy to reduce and control the level of dark current at APEX. Furthermore, the energy spectra of isolated sources have been measured. A simple model for energy data analysis was developed that allows one to extract information on the emitter from a single energy distribution measurement.

Perancangan Sistem Kontrol PID Untuk Pengendali Sumbu Elevasi Gun Pada Turret-Gun Kaliber 20 Milimeter

Directory of Open Access Journals (Sweden)

Dimas Kunto Ariwibowo

2017-01-01

Full Text Available Pertahanan negara pada hakikatnya adalah segala upaya pertahanan yang bersifat semesta yang didasarkan pada kesadaran atas hak dan kewajiban warga negara serta keyakinan pada kekuatan sendiri dengan tujuan untuk menjaga dan melindungi kedaulatan negara, keutuhan wilayah NKRI dan keselamatan segenap bangsa. Salah satu alat pendukung pertahanan yaitu senjata laras panjang, Turret-Gun.  Adapun langkah-langkah yang dilakukan dalam merancang pengendali PID Turret-Gun kaliber 20mm ini diawali dengan studi literatur serta studi lapangan mengenai mekanisme dan parameter-parameter yang terdapat pada Turret-Gun pada sumbu elevasi. Setelah itu dilakukan perancangan transmisi dan sistem kontrol Turret-Gun untuk dievaluasi grafik responnya yang akan digunakan sebagai acuan untuk merancang pengendali PID yang sesuai. Selanjutnya pengendali PID yang telah dirancang lalu disimulasikan, sehingga menghasilkan grafik respon yang sesuai dengan kriteria yang dibutuhkan. Hasil yang telah didapatkan dari penelitian ini adalah konstanta PID yang direkomendasikan untuk , , dan secara berturut-turut adalah sebesar 23061.024, 37820.07 dan 3515.4 yang menghasilkan transient response dengan nilai overshoot sebesar 19.9 % , steady state error sebesar 0 % serta settling time sebesar 0.935 detik. Hasil analisa kestabilan untuk sistem kontrol dengan konstanta PID tersebut menunjukkan bahwa sistem kontrol telah stabil, baik menggunakan metode Root Locus maupun metode Routh-Hurwitz.

Momentum equation for arc-driven rail guns

International Nuclear Information System (INIS)

Batteh, J.H.

1984-01-01

In several models of arc-driven rail guns, the rails are assumed to be infinitely high to simplify the calculation of the electromagnetic fields which appear in the momentum equation for the arc. This assumption leads to overestimates of the arc pressures and accelerations by approximately a factor of 2 for typical rail-gun geometries. In this paper, we develop a simple method for modifying the momentum equation to account for the effect of finite-height rails on the performance of the rail gun and the properties of the arc. The modification is based on an integration of the Lorentz force across the arc cross section at each axial location in the arc. Application of this technique suggests that, for typical rail-gun geometries and moderately long arcs, the momentum equation appropriate for infinite-height rails can be retained provided that the magnetic pressure term in the equation is scaled by a factor which depends on the effective inductance of the gun. The analysis also indicates that the magnetic pressure gradient actually changes sign near the arc/projectile boundary because of the magnetic fields associated with the arc current

rf traveling-wave electron gun for photoinjectors

Directory of Open Access Journals (Sweden)

Mattia Schaer

2016-07-01

Full Text Available The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.

Design of the gas cell for the IGISOL facility at ELI-NP

Energy Technology Data Exchange (ETDEWEB)

Constantin, P., E-mail: paul.constantin@eli-np.ro [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Balabanski, D.L. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Anh, L.T. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Cuong, P.V. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Centre of Nuclear Physics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Mei, B. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania)

2017-04-15

One of the experimental programs that will be carried out at the Extreme Light Infrastructure – Nuclear Physics (ELI-NP) facility is the production of exotic neutron-rich ion beams in an IGISOL facility via photofission in a stack of actinide targets placed at the center of a cell filled with He gas. Simulations with the Geant4 toolkit were done for the optimization of the target configuration that maximizes the rate of released photofission fragments. The cell geometry is established based on the stopping properties of these fragments. Studies, based on simulations with Geant4 and SIMION 8.1, of the space charge effect and its induced electric field in the gas cell are presented. Estimates of the extraction time and efficiency of the photofission fragments are derived.

Evaluation of Smart Gun Technologies preliminary report

Energy Technology Data Exchange (ETDEWEB)

Weiss, D.R.

1996-01-01

The Smart Gun Technology Project has a goal to eliminate the capability of an unauthorized user from firing a law enforcement officer`s firearm by implementing {open_quote}smart{close_quote} technologies. Smart technologies are those that can in some manner identify an officer. This report will identify, describe, and grade various technologies as compared to the requirements that were obtained from officers. This report does not make a final recommendation for a smart gun technology, nor does it give the complete design of a smart gun system.

High-Fidelity RF Gun Simulations with the Parallel 3D Finite Element Particle-In-Cell Code Pic3P

Energy Technology Data Exchange (ETDEWEB)

Candel, A; Kabel, A.; Lee, L.; Li, Z.; Limborg, C.; Ng, C.; Schussman, G.; Ko, K.; /SLAC

2009-06-19

SLAC's Advanced Computations Department (ACD) has developed the first parallel Finite Element 3D Particle-In-Cell (PIC) code, Pic3P, for simulations of RF guns and other space-charge dominated beam-cavity interactions. Pic3P solves the complete set of Maxwell-Lorentz equations and thus includes space charge, retardation and wakefield effects from first principles. Pic3P uses higher-order Finite Elementmethods on unstructured conformal meshes. A novel scheme for causal adaptive refinement and dynamic load balancing enable unprecedented simulation accuracy, aiding the design and operation of the next generation of accelerator facilities. Application to the Linac Coherent Light Source (LCLS) RF gun is presented.

Gun utopias? Firearm access and ownership in Israel and Switzerland.

Science.gov (United States)

Rosenbaum, Janet E

2012-02-01

The 2011 attempted assassination of a US representative renewed the national gun control debate. Gun advocates claim mass-casualty events are mitigated and deterred with three policies: (a) permissive gun laws, (b) widespread gun ownership, (c) and encouragement of armed civilians who can intercept shooters. They cite Switzerland and Israel as exemplars. We evaluate these claims with analysis of International Crime Victimization Survey (ICVS) data and translation of laws and original source material. Swiss and Israeli laws limit firearm ownership and require permit renewal one to four times annually. ICVS analysis finds the United States has more firearms per capita and per household than either country. Switzerland and Israel curtail off-duty soldiers' firearm access to prevent firearm deaths. Suicide among soldiers decreased by 40 per cent after the Israeli army's 2006 reforms. Compared with the United States, Switzerland and Israel have lower gun ownership and stricter gun laws, and their policies discourage personal gun ownership.

Analyses in Support of Risk-Informed Natural Gas Vehicle Maintenance Facility Codes and Standards: Phase II.

Energy Technology Data Exchange (ETDEWEB)

Blaylock, Myra L.; LaFleur, Chris Bensdotter; Muna, Alice Baca; Ehrhart, Brian David

2018-03-01

Safety standards development for maintenance facilities of liquid and compressed natural gas fueled vehicles is required to ensure proper facility design and operating procedures. Standard development organizations are utilizing risk-informed concepts to develop natural gas vehicle (NGV) codes and standards so that maintenance facilities meet acceptable risk levels. The present report summarizes Phase II work for existing NGV repair facility code requirements and highlights inconsistencies that need quantitative analysis into their effectiveness. A Hazardous and Operability study was performed to identify key scenarios of interest using risk ranking. Detailed simulations and modeling were performed to estimate the location and behavior of natural gas releases based on these scenarios. Specific code conflicts were identified, and ineffective code requirements were highlighted and resolutions proposed. These include ventilation rate basis on area or volume, as well as a ceiling offset which seems ineffective at protecting against flammable gas concentrations. ACKNOWLEDGEMENTS The authors gratefully acknowledge Bill Houf (SNL -- Retired) for his assistance with the set-up and post-processing of the numerical simulations. The authors also acknowledge Doug Horne (retired) for his helpful discussions. We would also like to acknowledge the support from the Clean Cities program of DOE's Vehicle Technology Office.

Understanding plasma spraying process and characteristics of DC-arc plasma gun (PJ-100

Directory of Open Access Journals (Sweden)

Jovana Ružić

2012-12-01

Full Text Available The thermal spray processes are a group of coating processes used to apply metallic or non-metallic coatings. In these processes energy sources are used to heat the coating material (in the form of powder, wire, or rod form to a molten or semi-molten state and accelerated towards a prepared surface by either carrier gases or atomization jets. In plasma spraying process, the spraying material is generally in the form of powder and requires a carrier gas to feed the powder into the plasma jet, which is passing between the hot cathode and the cylindrical nozzle-shaped anode. The design of DC plasma gun (PJ - 100 is designed and manufactured in Serbia. Plasma spaying process, the powder injection with the heat, momentum and mass transfers between particles and plasma jet, and the latest developments related to the production of DC plasma gun are described in this article.

Compact 5 x 1012 AMP/SEC rail-gun pulser for a laser plasma shutter

International Nuclear Information System (INIS)

Bradley, L.P.; Orham, E.L.; Stowers, I.F.

1979-01-01

We have developed a rail-gun plasma source to produce a plasma of 10 12 cm -3 particle density and project it with a velocity of 3.9 cm/μs. This device will be used in a output spatial filter of Nova to project a critical density plasma across an optical beam path and block laser retroreflected light. The object of this paper is to describe the design of a pulser appropriate to the Shiva laser fusion facility, and to describe the preliminary design of a higher current prototype pulser for Nova the laser fusion research facility under construction at Lawrence Livermore Laboratory

A high voltage test stand for electron gun qualification for LINACs

International Nuclear Information System (INIS)

Wanmode, Yashwant D.; Mulchandani, J.; Acharya, M.; Bhisikar, A.; Singh, H.G.; Shrivastava, Purushottam

2011-01-01

An electron gun lest stand has been developed at RRCAT. The test stand consists of a high voltage pulsed power supply, electron gun filament supply, grid supply, UHV system and electron gun current measurement system. Several electron guns developed indigenously were evaluated on this test stand. The shielding is provided for the electron gun set up. Electron gun tests can be tested upto 55 kV with pulse width of 15 microsecs and pulse repetition rates up to 200 Hz. The technical details of the subsystems are furnished and results of performance of the test stand have been reported in this paper. (author)

Reactor cover gas monitoring at the Fast Flux Test Facility

Energy Technology Data Exchange (ETDEWEB)

Bechtold, R A; Holt, F E; Meadows, G E; Schenter, R E [Westinghouse Hanford Company, Richland, WA (United States)

1987-07-01

The Fast Flux Test Facility (FFTF) is a 400 megawatt (thermal) sodium cooled reactor designed for irradiation testing of fuels, materials and components for LMRs. It is operated by the Westinghouse Hanford Company for the U. S. Department of Energy on the government-owned Hanford reservation near Richland, Washington. The first 100 day operating cycle began in April 1982 and the eighth operating cycle was completed In July 1986. Argon is used as the cover gas for all sodium systems at the plant. A program for cover gas monitoring has been in effect since the start of sodium fill in 1978. The argon is supplied to the FFTF by a liquid argon Dewar System and used without further purification. A liquid argon Dewar system provides the large volume of inert gas required for operation of the FFTF. The gas is used as received and is not recycled. Low concentrations of krypton and xenon in the argon supply are essential to preclude interference with the gas tag system. Gas chromatography has been valuable for detection of inadvertent air in leakage during refueling operations. A temporary system is installed over the reactor during outages to prevent oxide formation in the sodium vapor traps upstream from the on line gas chromatograph. On line gas monitoring by gamma spectrometry and grab sampling with GTSTs has been successful for the identification of numerous radioactive gas releases from creep capsule experiments as well as 9 fuel pin ruptures. A redundant fission gas monitoring system has been installed to insure constant surveillance of the reactor cover gas.

Gun barrel erosion - Comparison of conventional and LOVA gun propellants

NARCIS (Netherlands)

Hordijk, A.C.; Leurs, O.

2006-01-01

The research department Energetic Materials within TNO Defence, Security and Safety is involved in the development and (safety and insensitive munitions) testing of conventional (nitro cellulose based) and thermoplastic elastomer (TPE) based gun propellants. Recently our testing capabilities have

Spectrometer gun

Science.gov (United States)

Waechter, David A.; Wolf, Michael A.; Umbarger, C. John

1985-01-01

A hand-holdable, battery-operated, microprocessor-based spectrometer gun includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

CEBAF 200 kV Inverted Electron Gun

International Nuclear Information System (INIS)

Grames, J.M.; Adderley, P.A.; Clark, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.L.; Suleiman, R.; Surles-Law, K.E.L.

2011-01-01

Two DC high voltage GaAs photoguns have been built at Jefferson Lab based on a compact inverted insulator design. One photogun provides the polarized electron beam at CEBAF and operates at 130 kV bias voltage. The other gun is used for high average current lifetime studies at a dedicated test facility and has been operated at bias voltage up to 225 kV. The advantages of higher DC voltage for CEBAF include reduced space-charge emittance growth and the potential for prolonged photocathode lifetime. However, a consequence of operating at higher voltages is the increased likelihood of field emission or breakdown, both of which are unacceptable. Highlights of the R and D studies leading toward a production 200keV GaAs photogun for CEBAF will be presented.

Mass Shootings, Mental Illness, and Gun Control.

Science.gov (United States)

Philpott-Jones, Sean

2018-03-01

In the wake of the Stoneman Douglas School shooting, Republican and Democratic leaders-like the American electorate they represent-remain sharply divided in their responses to gun violence. They are united in their condemnation of these mass shootings, but they disagree about whether stricter or looser gun control laws are the answer. Those on the right side of the political aisle suggest that the issue is one of mental illness rather than gun control. Conversely, those who are more liberal or progressive in their political learnings are quick to condemn attempts to reframe the issue of mass shootings as a mental health problem. Both sides are wrong. Mass shootings are indeed partially a mental health problem, albeit one poorly addressed by our current laws and policies. But the solution to mass shootings also needs to consider strategies that may reduce gun violence in general. © 2018 The Hastings Center.

Test plan: Gas-threshold-pressure testing of the Salado Formation in the WIPP underground facility

International Nuclear Information System (INIS)

Saulnier, G.J. Jr.

1992-03-01

Performance assessment for the disposal of radioactive waste from the United States defense program in the WIPP underground facility must assess the role of post-closure was generation by waste degradation and the subsequent pressurization of the facility. be assimilated by the host formation will Whether or not the generated gas can be assimilated by the host formation will determine the ability of the gas to reach or exceed lithostatic pressure within the repository. The purpose of this test plan is (1) to present a test design to obtain realistic estimates of gas-threshold pressure for the Salado Formation WIPP underground facility including parts of the formation disturbed by the underground of the Salado, and (2) to provide a excavations and in the far-field or undisturbed part framework for changes and amendments to test objectives, practices, and procedures. Because in situ determinations of gas-threshold pressure in low-permeability media are not standard practice, the methods recommended in this testplan are adapted from permeability-testing and hydrofracture procedures. Therefore, as the gas-threshold-pressure testing program progresses, personnel assigned to the program and outside observers and reviewers will be asked for comments regarding the testing procedures. New and/or improved test procedures will be documented as amendments to this test plan, and subject to similar review procedures

Release isentrope measurements with the LLNL electric gun

Energy Technology Data Exchange (ETDEWEB)

Gathers, G.R.; Osher, J.E.; Chau, H.H.; Weingart, R.C.; Lee, C.G.; Diaz, E.

1987-06-01

The liquid-vapor coexistence boundary is not well known for most metals because the extreme conditions near the critical point create severe experimental difficulties. The isentropes passing through the liquid-vapor region typically begin from rather large pressures on the Hugoniot. We are attempting to use the high velocities achievable with the Lawrence Livermore National Laboratory (LLNL) electric gun to obtain these extreme states in aluminum and measure the release isentropes by releasing into a series of calibrated standards with known Hugoniots. To achieve large pressure drops needed to explore the liquid-vapor region, we use argon gas for which Hugoniots have been calculated using the ACTEX code, as one of the release materials.

Acceleration of solid pellets using a plasma gun

International Nuclear Information System (INIS)

Buller, T.L.; Turnbull, R.J.; Kim, K.

1979-01-01

The use of solid pellets of hydrogen isotopes to refuel thermonuclear fusion reactors based on the tokamak configuration will require that the pellets be accelerated to high velocities. One possible method of acceleration is to interact a fast plasma from a plasma gun with the pellets. In this paper preliminary results are given on the acceleration of solid pellets with a plasma gun. The plasma-gun requirements for successful acceleration to high velocities are discussed

Handgun waiting periods reduce gun deaths.

Science.gov (United States)

Luca, Michael; Malhotra, Deepak; Poliquin, Christopher

2017-11-14

Handgun waiting periods are laws that impose a delay between the initiation of a purchase and final acquisition of a firearm. We show that waiting periods, which create a "cooling off" period among buyers, significantly reduce the incidence of gun violence. We estimate the impact of waiting periods on gun deaths, exploiting all changes to state-level policies in the Unites States since 1970. We find that waiting periods reduce gun homicides by roughly 17%. We provide further support for the causal impact of waiting periods on homicides by exploiting a natural experiment resulting from a federal law in 1994 that imposed a temporary waiting period on a subset of states. Copyright © 2017 the Author(s). Published by PNAS.

Contoured-gap coaxial guns for imploding plasma liner experiments

Science.gov (United States)

Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.

2014-10-01

Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.

Unusual Case of Suicide With a Modified Trap Gun.

Science.gov (United States)

Vadysinghe, Amal; Dassanayake, Prasanna; Wickramasinghe, Medhani

2017-06-01

Trap gun is an illegal, locally manufactured gun with a basic trip system used to hunt wild animals. The body of a 28-year-old man was found in the jungle in supine position with both legs apart. A trap gun was between the legs pointing toward the cranial side of the body. It had 2 free wires that were not connected together. There was no evidence of foul play.The body had a single-entry wound (2.5-cm diameter) in the anterior chest, with blackening, burning, and tattooing. Six metal particles and nylon clothing material were embedded into soft tissue. No exit wound was found. Toxicology analysis reported an alcohol level of 72 mg/dL. The cause of death was multiple shrapnel injury to the chest at close to intermediate range by a single discharge from a trap gun. Circumstance was concluded as suicide.Ballistic and firearm experts opined that an illegal, manually operated, battery-powered ignition device was used to ignite the gun powder. We report the first case of suicide by a modified trap gun in literature.

Self-bunching electron guns

CERN Document Server

Mako, F; Weilhammer, Peter

1999-01-01

We report on three electron gun projects that are aimed at power tube and injector applications. The purpose of the work is to develop robust electron guns which produce self-bunched, high-current-density beams. We have demonstrated cold emission, long life, and tolerance to contamination. The cold emission process is based on secondary electron emission. FMT has studied this resonant bunching process which gives rise to high current densities (0.01-5 kA/cm/sup 2/), high charge bunches (up to 100 nC/bunch), and short pulses (1-100 ps) for frequencies from 1 to 12 GHz. The beam pulse width is nominally ~5% of the RF period. The first project is the L-Band Micro-Pulse Gun (MPG). Measurements show ~40 ps long microbunches at ~20 A/cm/sup 2/ without contamination due to air exposure. Lifetime testing has been carried out for about 18 months operating at 1.25 GHz for almost 24 hours per day at a repetition rate of 300 Hz and 5 mu s-long macro- pulses. About 5.8*10/sup 13/ micro-bunches or 62,000 coulombs have pass...

Field reversal produced by a plasma gun

International Nuclear Information System (INIS)

Hartman, C.W.; Condit, W.; Granneman, E.H.A.; Prono, D.; Smith, A.C. Jr.; Taska, J.; Turner, W.C.

1980-01-01

Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more the initial flux, possibly because of helical deformation of the current channel extending from the center electrode

The Brookhaven Accelerator Test Facility

International Nuclear Information System (INIS)

Batchelor, K.; Chou, T.S.; Fernow, R.C.

1988-01-01

The Brookhaven Accelerator Test Facility (ATF) will consist of a 50--100 MeV/c electron linac and a 100 GW CO 2 laser system. A high brightness RF-gun operating at 2856 MHz is to be used as the injector into the linac. The RF-gun contains a Nd:Yag-laser-driven photocathode capable of producing a stream of six ps electron pulses separated by 12.5 ns. The maximum charge in a micropulse will be one nano-Coulomb. The CO 2 laser pulse length will be a few picoseconds and will be synchronized with the electron pulse. The first experimental beam is expected in Fall 89. The design electron beam parameters are given and possible initial experiments are discussed. 9 refs., 1 fig., 3 tabs