WorldWideScience

Sample records for pierce electron guns

  1. Accurate model of electron beam profiles with emittance effects for pierce guns

    Science.gov (United States)

    Zeng, Peng; Wang, Guangqiang; Wang, Jianguo; Wang, Dongyang; Li, Shuang

    2016-09-01

    Accurate prediction of electron beam profile is one of the key objectives of electron optics, and the basis for design of the practical electron gun. In this paper, an improved model describing electron beam in Pierce gun with both space charge effects and emittance effects is proposed. The theory developed by Cutler and Hines is still applied for the accelerating region of the Pierce gun, while the motion equations of the electron beams in the anode aperture and drift tunnel are improved by modifying electron optics theory with emittance. As a result, a more universal and accurate formula of the focal length of the lens for the electron beam with both effects is derived for the anode aperture with finite dimension, and a modified universal spread curve considering beam emittance is introduced in drift tunnel region. Based on these improved motion equations of the electron beam, beam profiles with space charge effects and emittance effects can be theoretically predicted, which are subsequently approved to agree well with the experimentally measured ones. The developed model here is helpful to design more applicable Pierce guns at high frequencies.

  2. ELECTRON GUN

    Science.gov (United States)

    Christofilos, N.C.; Ehlers, K.W.

    1960-04-01

    A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

  3. 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.

  4. Electron gun for SSRF

    Institute of Scientific and Technical Information of China (English)

    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.

  5. 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.

  6. Wisconsin SRF Electron Gun Commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Bisognano, Joseph J. [University of Wisconsin-Madison; Bissen, M. [University of Wisconsin-Madison; Bosch, R. [University of Wisconsin-Madison; Efremov, M. [University of Wisconsin-Madison; Eisert, D. [University of Wisconsin-Madison; Fisher, M. [University of Wisconsin-Madison; Green, M. [University of Wisconsin-Madison; Jacobs, K. [University of Wisconsin-Madison; Keil, R. [University of Wisconsin-Madison; Kleman, K. [University of Wisconsin-Madison; Rogers, G. [University of Wisconsin-Madison; Severson, M. [University of Wisconsin-Madison; Yavuz, D. D. [University of Wisconsin-Madison; Legg, Robert A. [JLAB; Bachimanchi, Ramakrishna [JLAB; Hovater, J. Curtis [JLAB; Plawski, Tomasz [JLAB; Powers, Thomas J. [JLAB

    2013-12-01

    The University of Wisconsin has completed fabrication and commissioning of a low frequency (199.6 MHz) superconducting electron gun based on a quarter wave resonator (QWR) cavity. Its concept was optimized to be the source for a CW free electron laser facility. The gun design includes active tuning and a high temperature superconducting solenoid. We will report on the status of the Wisconsin SRF electron gun program, including commissioning experience and first beam measurements.

  7. a Bombardment Heated Lanthanum-Hexaboride Thermionic Cathode Electron Gun.

    Science.gov (United States)

    Herniter, Marc Efrem

    This dissertation concerns the development and operation of a high current density Pierce-type electron gun with a 0.75-inch-diameter lanthanum hexaboride (LaB _6) thermionic cathode. The objective of this research is to achieve as high a current density as possible from the lanthanum hexaboride cathode. The topics which are addressed are the cathode heating and control system, the Pierce-type electron gun design, and the high voltage pulsing and isolation system. Lanthanum hexaboride is used as a cathode material in applications where high current density and resistance to chemical poisoning are important. Applications include free electron lasers and high power microwave generation. A four stage Marx generator capable of producing 140-kV-peak pulses with a 16 mus decay time constant is used to pulse the electron gun. The cathode is heated to temperatures greater than 1800 ^circ C by electron bombardment from a tungsten filament. Both temperature-limited and space -charge-limited bombardment methods have been investigated. The temperature-limited method is open-loop unstable. Analog and digital control circuits have been developed to control this instability. A simple heating model has been developed and criteria for constructing a controllable system have been established. An instability in the heating system which is caused by evaporation of lanthanum hexaboride from the cathode is discussed. This evaporation reduces the work function of the bombarding filament and makes the temperature -limited bombardment system uncontrollable. The gun has been operated up to voltages of 115 kV achieving beam current densities of 30 A/cm ^2. The electron gun operated dependably up to voltages of 90 kV achieving temperature-limited currents of 50 A. Due to the high fields at the tip of the Pierce -focusing electrode the gun would usually arc at voltages greater than 90 kV. Electron gun operation has been observed in the temperature-limited and space-charge-limited regimes. The

  8. Simulations of Gaussian electron guns for RHIC electron lens

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-02-28

    Simulations of two versions of the electron gun for RHIC electron lens are presented. The electron guns have to generate an electron beam with Gaussian radial profile of the electron beam density. To achieve the Gaussian electron emission profile on the cathode we used a combination of the gun electrodes and shaping of the cathode surface. Dependence of electron gun performance parameters on the geometry of electrodes and the margins for electrodes positioning are presented.

  9. 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.

  10. 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.

  11. One nanosecond pulsed electron gun systems

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. 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.

  13. Toward a terahertz-driven electron gun

    Science.gov (United States)

    Huang, W. Ronny; Nanni, Emilio A.; Ravi, Koustuban; Hong, Kyung-Han; Fallahi, Arya; Wong, Liang Jie; Keathley, Phillip D.; Zapata, Luis E.; Kärtner, Franz X.

    2015-01-01

    Femtosecond electron bunches with keV energies and eV energy spread are needed by condensed matter physicists to resolve state transitions in carbon nanotubes, molecular structures, organic salts, and charge density wave materials. These semirelativistic electron sources are not only of interest for ultrafast electron diffraction, but also for electron energy-loss spectroscopy and as a seed for x-ray FELs. Thus far, the output energy spread (hence pulse duration) of ultrafast electron guns has been limited by the achievable electric field at the surface of the emitter, which is 10 MV/m for DC guns and 200 MV/m for RF guns. A single-cycle THz electron gun provides a unique opportunity to not only achieve GV/m surface electric fields but also with relatively low THz pulse energies, since a single-cycle transform-limited waveform is the most efficient way to achieve intense electric fields. Here, electron bunches of 50 fC from a flat copper photocathode are accelerated from rest to tens of eV by a microjoule THz pulse with peak electric field of 72 MV/m at 1 kHz repetition rate. We show that scaling to the readily-available GV/m THz field regime would translate to monoenergetic electron beams of ~100 keV. PMID:26486697

  14. Secondary emission electron gun using external primaries

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Ben-Zvi, Ilan

    2009-10-13

    An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

  15. Secondary emission electron gun using external primaries

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Ben-Zvi, Ilan; Kewisch, Jorg; Chang, Xiangyun

    2007-06-05

    An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

  16. Microwave electron gun theory and experiments

    Science.gov (United States)

    Gao, J.

    1992-01-01

    A general microwave electron gun (rf gun) theory and some new ideas about further reducing the emittance of electron beams are reviewed and introduced briefly. Experimental results are presented from a thermionic cathode rf gun which has been developed for Beijing Free-Electron Laser Project (BFELP) at Institute of High Energy Physics (IHEP), Academia Sinica as the injector of 30 MeV constant gradient linac. LaB6 is used as the thermionic emitter with 100 crystal surface and the temperature around 1620 °C. Back bombardment heating effect and another effect connected with the cathode surface temperature was observed. An electron beam with macropulse length 4 μs, repetition rate 12.5 Hz, greater than 500 mA beam current during macropulse and around 1 MeV maximum energy has been obtained. In the last section of this article, two useful formulas used to determine electric field distribution near the cathode surface and coupling coefficient β of a rf gun are introduced.

  17. 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 • mec • 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 • me • μm.

  18. 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.

  19. High perveance electron gun for the electron cooling system

    CERN Document Server

    Korotaev, Yu V; Petrov, A; Sidorin, A; Smirnov, A; Syresin, E M; Titkova, I

    2000-01-01

    The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 mu A/V sup 3 sup / sup 2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual).

  20. NASCAP simulation of laboratory charging tests using multiple electron guns

    Science.gov (United States)

    Mandell, M. J.; Katz, I.; Parks, D. E.

    1981-01-01

    NASCAP calculations have been performed simulating exposure of a spacecraft-like model to multiple electron guns. The results agree well with experiment. It is found that magnetic field effects are fairly small, but substantial differential charging can result from electron gun placement. Conditions for surface flashover are readily achieved.

  1. Electron-beam-controlled laser with a grid-controlled electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Avanesyan, V.S.; Dutov, A.I.; Lakhno, Y.V.; Malkhov, L.N.

    1977-08-01

    An experimental investigation was made of an electron-beam-controlled carbon dioxide laser with an electron gun in which the beam current was modulated by a control grid. The design features of the electron gun and laser are described and their performance is reported. Observations of instabilities of the electron beam in the gun are reported and methods for eliminating them are suggested.

  2. Compact electron gun based on secondary emission through ionic bombardment.

    Science.gov (United States)

    Diop, Babacar; Bonnet, Jean; Schmid, Thomas; Mohamed, Ajmal

    2011-01-01

    We present a new compact electron gun based on the secondary emission through ionic bombardment principle. The driving parameters to develop such a gun are to obtain a quite small electron gun for an in-flight instrument performing Electron Beam Fluorescence measurements (EBF) on board of a reentry vehicle in the upper atmosphere. These measurements are useful to characterize the gas flow around the vehicle in terms of gas chemical composition, temperatures and velocity of the flow which usually presents thermo-chemical non-equilibrium. Such an instrument can also be employed to characterize the upper atmosphere if placed on another carrier like a balloon. In ground facilities, it appears as a more practical tool to characterize flows in wind tunnel studies or as an alternative to complex electron guns in industrial processes requiring an electron beam. We describe in this paper the gun which has been developed as well as its different features which have been characterized in the laboratory.

  3. Low Emittance Guns for the ILC Polarized Electron Beam

    Science.gov (United States)

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

    2007-06-01

    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.

  4. Method of electron emission control in RF guns

    CERN Document Server

    Khodak, I V

    2001-01-01

    The electron emission control method for a RF gun is considered.According to the main idea of the method,the additional resonance system is created in a cathode region where the RF field strength could be varied using the external pulse equipment. The additional resonance system is composed of a coaxial cavity coupled with a RF gun cylindrical cavity via an axial hole. Computed results of radiofrequency and electrodynamic performances of such a two-cavity system and results of the RF gun model pilot study are presented in. Results of particle dynamics simulation are described.

  5. The system of RF beam control for electron gun

    Science.gov (United States)

    Barnyakov, A. M.; Chernousov, Yu. D.; Ivannikov, V. I.; Levichev, A. E.; Shebolaev, I. V.

    2015-06-01

    The system of RF control of three-electrode electron gun current is described. It consists of a source of microwave signal, coaxial line, coaxial RF switch and RF antenna lead. The system allows one to get the electron beam in the form of bunches with the frequency of the accelerating section to achieve the capture of particles in the acceleration mode close to 100%. The results of calculation and analysis of the elements of the system are presented. Characteristics of the devices are obtained experimentally. The results of using RF control in three-electrode electron gun at electron linear accelerator are described.

  6. A novel electron gun for inline MRI-linac configurations

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, Dragoş E., E-mail: dragos.constantin@varian.com; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Holloway, Lois [Liverpool and Macarthur Cancer Therapy Centres, The University of Sydney, NSW 2006 (Australia); Keall, Paul J. [Radiation Physics Laboratory, The University of Sydney, NSW 2006 (Australia)

    2014-02-15

    Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

  7. Study of a laser-heated electron gun

    Science.gov (United States)

    Roy, P. K.; Moon, A.; Mima, K.; Nakai, S.; Fujita, M.; Imasaki, K.; Yamanaka, C.; Yasuda, E.; Watanabe, T.; Ohigashi, N.; Okuda, Y.; Tsunawaki, Y.

    1996-12-01

    A method of cathode heating using a laser was studied for an electron gun. In order to observe the practicality of the heating system, the characteristics of the laser-heated gun with a dispenser and LaB6 thermionic cathodes have been experimentally investigated. The direct laser irradiation is so efficient that the gun is equipped without heat shielding, a cooling system, or an electrical circuit in the gun chamber for cathode heating. Modeling, based on the experimental data, indicates that the cathode temperature is proportional to one-fourth power of the laser power and that laser power loss and conduction loss of heat in the gun assembly are negligible. An electron beam current density 0.48 A/cm2 was measured with 26 W laser power for a dispenser cathode of 0.06 cm2 emission area. Current density 0.16 A/cm2 with 25 W was recorded for a LaB6 cathode of area 0.12 cm2. Electron beam emittance has been measured by using the typical pepper-pot technique. It was observed that the growth of electron beam emittance was very small in the laser heating.

  8. Development of Field-Emission Electron Gun from Carbon Nanotubes

    CERN Document Server

    Hozumi, Y

    2004-01-01

    Aiming to use a narrow energy-spread electron beam easily and low costly on injector electron guns, we have been tested field emission cathodes of carbon nanotubes (CNTs). Experiments for these three years brought us important suggestions and a few rules of thumb. Now at last, anode current of 3.0 [A/cm2

  9. Preliminary design for a pierce wiggler beamstick and addendum

    Energy Technology Data Exchange (ETDEWEB)

    Pirkle, D.

    1988-05-01

    Lawrence Livermore National Laboratory is developing a fast tunable microwave source for operation at 250 GHz and 10kW peak output power. This report presents the preliminary design of a Pierce gun and solenoid magnet that will be compatible with a Pierce-wiggler electron beam formation system (beamstick). The beamstick will be an appropriate power source for a tunable gyro-BWO at 250 GHz. Figure 1 presents the major components of the Pierce-wiggler beamstick: the electron gun, solenoid, beam tunnel, wiggler, and vacuum valve. Figure 2 shows an artistic conception of how the beamstick will interface with the interaction magnet, modulator and gyro-BWO circuit at MIT. 15 figs.

  10. Electron gun for diffraction experiments on controlled molecules

    CERN Document Server

    Müller, Nele L M; Długołecki, Karol; Küpper, Jochen

    2015-01-01

    A dc electron gun, generating picosecond pulses with up to $8\\times10^{6}$ electrons per pulse, was developed. Its applicability for future time-resolved-diffraction experiments on state- and conformer-selected laser-aligned or oriented gaseous samples was characterized. The focusing electrodes were arranged in a velocity-map imaging spectrometer configuration. This allowed to directly measure the spatial and velocity distributions of the electron pulses emitted from the cathode. In combination with electron trajectory simulations, this permitted the characterization of the electron beam in terms of coherence length and pulse duration. Electron diffraction data of a thin aluminum foil illustrated the diffraction capabilities of the electron-gun setup.

  11. Longitudinal Jitter Analysis of a Linear Accelerator Electron Gun

    Directory of Open Access Journals (Sweden)

    MingShan Liu

    2016-11-01

    Full Text Available We present measurements and analysis of the longitudinal timing jitter of a Beijing Electron Positron Collider (BEPCII linear accelerator electron gun. We simulated the longitudinal jitter effect of the gun using PARMELA to evaluate beam performance, including: beam profile, average energy, energy spread, and XY emittances. The maximum percentage difference of the beam parameters is calculated to be 100%, 13.27%, 42.24% and 65.01%, 86.81%, respectively. Due to this, the bunching efficiency is reduced to 54%. However, the longitudinal phase difference of the reference particle was 9.89°. The simulation results are in agreement with tests and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

  12. A pulsed electron gun for the Plane Wave Transformer Linac

    CERN Document Server

    Mahadevan, S; Nandedkar, R V

    2003-01-01

    A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 mu perv and the normalized emittance is within 5 pi mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

  13. Longitudinal jitter analysis of linear accelerator electron gun

    CERN Document Server

    Mingshan, Liu; Iqbal, Munawar

    2015-01-01

    We present measurement and analyses of longitudinal timing jitter of Beijing Electron Positron Collider (BEPCII) linear accelerator electron gun. We simulated longitudinal jitter effect of the gun using PARMELA about beam performance including beam profile, average energy, energy spread, longitudinal phase of reference particle and XY emittance. The maximum percentage difference of the beam parameters are calculated to be; 100%, 13.27%, 42.24%, 7.79% and 65.01%, 86.81%, respectively due to which the bunching efficiency is reduced to 54%. The simulation results are in agreement with test and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

  14. 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.

  15. Body Piercing

    Science.gov (United States)

    ... most common body piercing. Other common places to pierce include the eyebrow, nose, tongue, lip, belly button, nipples, and genitals. Some people also pierce their ear cartilage (the hard part of the ...

  16. Terahertz-driven, all-optical electron gun

    CERN Document Server

    Huang, W Ronny; Wu, Xiaojun; Cankaya, Huseyin; Calendron, Anne-Laure; Ravi, Koustuban; Zhang, Dongfang; Nanni, Emilio A; Hong, Kyung-Han; Kärtner, Franz X

    2016-01-01

    Ultrashort electron beams with narrow energy spread, high charge, and low jitter are essential for resolving phase transitions in metals, semiconductors, and molecular crystals. These semirelativistic beams, produced by phototriggered electron guns, are also injected into accelerators for x-ray light sources. The achievable resolution of these time-resolved electron diffraction or x-ray experiments has been hindered by surface field and timing jitter limitations in conventional RF guns, which thus far are 96 fs, respectively. A gun driven by optically-generated single-cycle THz pulses provides a practical solution to enable not only GV/m surface fields but also absolute timing stability, since the pulses are generated by the same laser as the phototrigger. Here, we demonstrate an all-optical THz gun yielding peak electron energies approaching 1 keV, accelerated by 300 MV/m THz fields in a novel micron-scale waveguide structure. We also achieve quasimonoenergetic, sub-keV bunches with 32 fC of charge, which ca...

  17. Design and Analysis of an Electron Gun/Booster and Free Electron Laser Optical Theory

    Science.gov (United States)

    2010-09-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA DISSERTATION DESIGN AND ANALYSIS OF AN ELECTRON GUN/BOOSTER AND FREE ELECTRON LASER OPTICAL THEORY by...298-102 September 2010 Dissertation Design and Analysis of an Electron Gun/Booster and Free Electron Laser Optical Theory Niles, Sean P. Naval...motor attached to a spool for adjusting the bead’s position in the cavity. The bead is a small piece of stainless steel hypodermic needle threaded

  18. Thermomechanical Impact of Polyurethane Potting on Gun Launched Electronics

    Directory of Open Access Journals (Sweden)

    A. S. Haynes

    2013-01-01

    Full Text Available Electronics packages in precision guided munitions are used in guidance and control units, mission computers, and fuze-safe-and-arm devices. They are subjected to high g-loads during gun launch, pyrotechnic shocks during flight, and high g-loads upon impact with hard targets. To enhance survivability, many electronics packages are potted after assembly. The purpose of the potting is to provide additional structural support and shock damping. Researchers at the US Army recently completed a series of dynamic mechanical tests on a urethane-based potting material to assess its behavior in an electronics assembly during gun launch and under varying thermal launch conditions. This paper will discuss the thermomechanical properties of the potting material as well as simulation efforts to determine the suitability of this potting compound for gun launched electronics. Simulation results will compare stresses and displacements for a simplified electronics package with and without full potting. An evaluation of the advantages and consequences of potting electronics in munitions systems will also be discussed.

  19. Extension of Pierce model to multiple transmission lines interacting with an electron beam

    CERN Document Server

    Tamma, Venkata Ananth

    2013-01-01

    A possible route towards achieving high power microwave devices is through the use of novel slow-wave structures employing multiple coupled transmission lines (MTLs) whose behavior when coupled to electron beams have not been sufficiently explored. We present the extension of the one-dimensional linearized Pierce theory to MTLs coupled to a single electron beam. We develop multiple formalisms to calculate the k-{\\omega} dispersion relation of the system and find that the existence of a growing wave solution is always guaranteed if the electron propagation constant is larger than or equal to the largest propagation constant of the MTL system. We verify our findings with illustrative examples which bring to light unique properties of the system in which growing waves were found to exist within finite bands of the electron propagation constant and discuss possible approach to improve the gain. By treating the beam-MTL interaction as distributed dependent current generators in the MTL, we derive relations charact...

  20. Design and numerical simulation of thermionic electron gun

    CERN Document Server

    Hosseinzadeh, M

    2015-01-01

    This paper reports the simulation of an electron gun. The effects of some parameters on the beam quality were studied and optimal choices were identified. It gives numerical beam qualities in common electrostatic triode gun, and the dependences on design parameters such as electrode geometries and bias voltages to these electrodes are shown. An electron beam of diameter 5 mm with energy of five kilo electron volt was assumed for simulation process. Some design parameters were identified as variable parameters in the presence of space charge. These parameters are the inclination angle of emission electrode, the applied voltage to focusing electrode, the gap width between the emission electrode and the focusing electrode and the diameter of the focusing electrode. The triode extraction system is designed and optimized by using CST software (for Particle Beam Simulations). The physical design of the extraction system is given in this paper. From the simulation results, it is concluded that the inclination angle ...

  1. Analysis of magnetically immersed electron guns with non-adiabatic fields

    Science.gov (United States)

    Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; Raparia, Deepak; Ritter, John

    2016-11-01

    Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams with high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map, different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. The tests' results of a non-adiabatic electron gun with modified magnetic field are presented.

  2. Note: Thermal analysis of the long line source electron gun

    Science.gov (United States)

    Iqbal, M.; Wasy, A.; Lodhi, M. A. K.

    2013-05-01

    We performed thermal analysis for our previously reported [M. Iqbal, K. Masood, M. Rafiq, M. A. Chaudhry, and F. Aleem, Rev. Sci. Instrum. 74, 4616 (2003), 10.1063/1.1614852], long linear filament electron gun assembly using ANSYS software. The source was set under a thermal load of 3000 °C, to evaluate temperature distribution, thermal strain, and heat flux at various components of the gun. We calculated the maximum heat flux (9.0 W/mm2) that produced a thermal strain of 0.05 at the focusing electrodes. However, the minimum value of the heat flux (0.3 W/mm2) was at the anode electrodes which correspond to a negligible thermal strain. The gun was validated experimentally showing a uniform cross section of the beam at the molybdenum work plate comparable to the size of the filament. Our experimental and theoretical results are in agreement. The gun had been in continuous operation for several hours at high temperatures without any thermal run-out.

  3. A ferroelectric electron gun in a free-electron maser experiment

    CERN Document Server

    Einat, M; Rosenman, G

    2002-01-01

    An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 mu s pulse width. The pulse repetition frequency attains 3.1 MHz in approx 50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices.

  4. Note: Simulation and test of a strip source electron gun

    Science.gov (United States)

    Iqbal, Munawar; Islam, G. U.; Misbah, I.; Iqbal, O.; Zhou, Z.

    2014-06-01

    We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm2, respectively, that corresponds to power density of 11.5 kW/cm2, at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters.

  5. A terahertz-driven electron gun

    CERN Document Server

    Huang, W Ronny; Ravi, Koustuban; Hong, Kyung-Han; Wong, Liang Jie; Keathley, Phillip D; Fallahi, A; Zapata, Luis; Kärtner, Franz X

    2014-01-01

    Electron sources at keV-MeV energies are indispensable for applications such as ultrafast electron diffraction, x-ray generation, and electron energy-loss spectroscopy. However, the accessibility and size of current accelerators based on radio-frequency (RF) technology are limited by the achievable electric fields. Terahertz based accelerators promise unprecedented compactness compared to current RF accelerators due to the intense electric fields that can be applied in the accelerating structures. Here, electron bunches of 50 fC from a flat copper photocathode are accelerated from rest to a mean energy of 18 eV by a single-cycle THz field with peak electric field gradient of 72 MV/m at 1 kHz repetition rate. Scaling of the THz field into the gigavolt per meter regime would translate to electron energies of ~100 keV. Furthermore, in combination with the recent demonstration of a THz linear accelerator (linac), this is a milestone toward a millimeter- to centimeter-scale relativistic electron source.

  6. A high current, high gradient, laser excited, pulsed electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Batchelor, K.; Farrell, J.P.; Dudnikova, G. [Brookhaven Technology Group, Inc., Stony Brook, NY (United States); Ben-Zvi, I.; Srinivasan-Rao, T.; Smedley, J.; Yakimenko, V. [Brookhaven National Lab., Upton, NY (United States)

    1998-06-01

    This paper describes a pulsed electron gun that can be used as an FEL, as an injector for electron linear accelerators or for rf power generation. It comprises a 1 to 5 MeV, 1 to 2 ns pulsed power supply feeding a single diode, photoexcited acceleration gap. Beam quality of a {approximately}1nC charge in {approximately}1 GV/m field was studied. Computations of the beam parameters as a function of electrode configuration and peak electron current are presented together with descriptions of the power supply, laser and beam diagnostics systems.

  7. Emittance minimization at the ELBE superconducting electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, K.; Arnold, A.; Lu, P.; Murcek, P.; Teichert, J.; Vennekate, H.; Xiang, R.

    2014-07-01

    The transverse emittance is one of the most important quantities which characterize the quality of an electron source. For high quality experiments low beam emittance is required. By means of theoretical considerations and simulation calculations we have studied how the emittance of the Rossendorf superconducting radio-frequency photoelectron source (SRF gun) can be minimized. It turned out that neither a solenoid magnet nor the effect of space charge forces is needed to create a pronounced emittance minimum. The minimum appears by just adjusting the starting phase of the electron bunch with respect to the RF phase of the gun in a suitable way. Investigation of various correlations between the properties of the beam particles led to an explanation on how the minimum comes about. It is shown that the basic mechanism of minimization is the fact that the longitudinal properties of the particles (energy) are strongly influenced by the starting phase. Due to the coupling of the longitudinal and transverse degrees of freedom by the relativistic equation of motion the transverse degrees of freedom and thereby the emittance can be strongly influenced by the starting phase as well. The results obtained in this study will be applied to minimize the emittance in the commissioning phase of the SRF gun.

  8. Calculation of Electron Beam Potential Energy from RF Photocathode Gun

    CERN Document Server

    Liu Wan Ming; Power, John G; Wang, Haitao

    2005-01-01

    In this paper, we consider the contribution of potential energy to beam dynamics as simulated by PARMELA at low energies (10 - 30MeV). We have developed a routine to calculate the potential energy of the relativistic electron beam using the static coulomb potential in the rest frame (first order approximation as in PARMELA). We found that the potential energy contribution to the beam dynamics could be very significant, particularly with high charge beams generated by an RF photocathode gun. Our results show that when the potential energy is counted correctly and added to the kinetic energy from PARMELA, the total energy is conserved. Simulation results of potential and kinetic energies for short beams (~1 mm) at various charges (1 - 100 nC) generated by a high current RF photocathode gun are presented.

  9. Simulated Performance of the Wisconsin Superconducting Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Bosch, K.J. Kleman, R.A. Legg

    2012-07-01

    The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.

  10. Experimental investigation of electron guns for THz microwave vacuum amplifiers

    Science.gov (United States)

    Burtsev, A. A.; Grigor'ev, Yu. A.; Navrotsky, I. A.; Rogovin, V. I.; Sakhadzhi, G. V.; Shumikhin, K. V.

    2016-05-01

    Single-sheet and multiple beam electron emitters based on thermionic minicathodes for terahertz traveling-wave tubes have been studied. Data are presented for impregnated blade thermionic cathode with dimensions 0.1 × 0.7 mm and a maximum current density of 114 A/cm2 in a pulsed mode. A variant of the five-beam electron gun with 0.25-mm-diameter cylindrical minicathodes in cells of a control grid is proposed that provides a current density of 85.5 A/cm2 at a grid potential of 900-1000 V.

  11. Final Technical Report- Back-gate Field Emission-based Cathode RF Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, Gary; Martin, Allen; Noonan, John

    2010-10-30

    The objective was to complete the design of an electron gun which utilizes a radio frequency (RF) power source to apply a voltage to a field emission (FE) cathode, a so called cold cathode, in order to produce an electron beam. The concept of the RF electron gun was originally conceived at Argonne National Laboratory but never reduced to practice. The research allowed the completion of the design based upon the integration of the FE electron source. Compared to other electron guns, the RF gun is very compact, less than one third the size of other comparable guns, and produces a high energy (to several MeV), high quality, high power electron beam with a long focal length with high repetition rates. The resultant electron gun may be used in welding, materials processing, analytical equipment and waste treatment.

  12. Modular Low-Heater-Power Cathode/Electron Gun Assembly for Microwave and Millimeter Wave Traveling Wave Tubes

    Science.gov (United States)

    Wintucky, Edwin G.

    2000-01-01

    cathode/electron gun assembly consists of four subassemblies the cathode, the focus electrode, the header (including the electrical feedthroughs), and the gun envelope (including the anode) a diagram of which is shown. The modular construction offers a number of significant advantages, including flexibility of design, interchangeability of parts, and a drop-in final assembly procedure for quick and accurate alignment. The gun can accommodate cathodes ranging in size from 0.050 to 0.250-in. in diameter and is applicable to TWT's over a broad range of sizes and operating parameters, requiring the substitution of only a few parts: that is, the cathode, focus electrode, and anode. The die-pressed cathode pellets can be made with either flat or concave (Pierce gun design) emitting surfaces. The gun can be either gridded (pulse operation) or ungridded (continuous operation). Important factors contributing to low cost are the greater use of CRT materials and parts, the standardization of processes (welding and mechanical capture), and tooling amenable to automated production. Examples are the use of simple shapes, drawn or stamped metal parts, and parts joined by welding or mechanical capture. Feasibility was successfully demonstrated in the retrofit and testing of a commercial Kaband (22-GHz) TWT. The modular cathode/electron gun assembly was computer modeled to replicate the performance of the original electron gun and fabricated largely from existing CRT parts. Significant test results included demonstration of low heater power (1.5-W, 1010 C brightness temperature for a 0.085-in.-diameter cathode), mechanical ruggedness (100g shock and vibration tests in accordance with military specifications (MIL specs)), and a very fast warmup. The results of these tests indicate that the low-cost CRT manufacturing approach can be used without sacrificing performance and reliability.

  13. R&D ERL: SRF Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    Burrill, A.

    2010-01-01

    When the BNL high current ERL was first envisioned the choice of injector went through several iterations before concluding that an SRF injector was the appropriate choice for the task at hand. The design requirements were quite stringent as the injector had to be designed to reach currents never before achieved in any injector. The overall goal was to design an injector capable of delivering up to 0.5 Ampere at 703.75 MHz. This criteria was set based on the need to demonstrate high average current energy recovery at the ERL so that future machines could be designed and built with confidence in the injector. For the ERL the injector needs to be capable of accelerating electrons to 2-2.5 MeV with charges ranging from 0.7 to 5 nC per bunch depending on the operational parameters being studied. These criteria led to a 1/2 cell photoinjector designed to accommodate a demountable photocathode utilizing a novel quarter wave choke joint for the cathode insertion mechanism. The cavity requires a total of 1 MW of power coupled to the beam in order to meet the high current application, necessitating two 500 kW RF power couplers. This AP note will review the overall physics design and analysis, the fabrication sequence, and the testing plan for this cavity.

  14. An angular selective electron gun for the KATRIN experiment

    Energy Technology Data Exchange (ETDEWEB)

    Zacher, Michael; Ortjohann, Hans-Werner; Steinbrink, Nicholas; Josten, Lorenz; Hannen, Volker; Weinheimer, Christian; Winzen, Daniel [Westfaelische Wilhelms-Universitaet, Muenster (Germany); Collaboration: KATRIN-Collaboration

    2013-07-01

    The KArlsruhe TRItium Neutrino experiment aims for a measurement of the electron anti-neutrino mass with a sensitivity of 200 meV/c{sup 2} (95% C.L.) by analysing the endpoint region of the tritium β-decay. The main spectrometer (MAC-E filter type, 23m length) is one of the central parts of the experiment, featuring an energy resolution of Δ E<1 eV. For commissioning of the spectrometer a well defined electron source is needed that allows to determine the transmission characteristics and compare the electromagnetic properties to simulations. For this purpose an angular selective electron gun was developed. A pulsed UV-Laser produces electrons via the photo-electric effect, which are then accelerated electrostatically in a magnetic field. It features a small energy spread, a sharp selectable emission angle and covers the whole magnetic flux tube of KATRIN. By that, the characteristics of the spectrometer can be investigated with high precision. The time structure of the electron pulses allows time of flight measurements, offering enhanced sensitivity. The talk gives an overview about the e-gun design and its properties.

  15. Development of Electron Gun of Carbon Nanotube Cathode

    CERN Document Server

    Hozumi, Yasufumi; Ohsawa, Satoshi; Sugimura, Takashi

    2005-01-01

    We are developing high brightness electron guns utilizing carbon nanotube (CNT) cathodes. Recently, we succeeded to achieved field emission currents to 0.2 A (3 A/cm2) from a triode type CNT cathode of 3 mm diameter. The emission tests were performed at DC100kV acceleration voltage in pulse operations of 50 Hz using 6 nsec pulses. The emission currents were very stable for long term periods of 3 weeks. Photo emission tests from CNT cathode by 266nm laser pulses is also due to be reported simultaneously.

  16. Construction and Test of a Novel Superconducting RF Electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Bisognano, Joseph J. [University of Wisconsin-Madison

    2014-04-16

    The University of Wisconsin-Madison has completed installation of a superconducting electron gun. Its concept was optimized to be the source for a CW free electron laser facility with multiple megahertz repetition rate end stations. This VHF superconducting configuration holds the promise of the highest performance for CW injectors. Initial commissioning efforts show that the cavity can achieve gradients of 35 MV/m at the cathode position. With the cathode inserted CW operation has been achieved at 20 MV/m with good control of microphonics, negligible dark current, and Q0 > 3×109 at 4 K. Bunch charges of ~100 pC have been delivered, and first simple beam measurements made. These preliminary results are very encouraging for production of 100s pC bunches with millimeter-milliradian or smaller normalized emittances. Plans are in place to carry out more definitive studies to establish the full capabilities. However, since the grant was not renewed, the electron gun is currently mothballed, and without supplemental fund the opportunity for further work will be lost.

  17. Electron guns and collectors developed at INP for electron cooling devices

    Energy Technology Data Exchange (ETDEWEB)

    Sharapa, A.N.; Shemyakin, A.V. [Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-09-01

    Institute of Nuclear Physics (INP) has a rich experience in designing electron guns and collectors for electron cooling devices. This paper is a review of the experience of several INP research groups in this field. Some results obtained at INP for systems without a guiding magnetic field are also discussed.

  18. Edge shadow projection method for measuring the brightness of electron guns

    Science.gov (United States)

    Han, Cheolsu; Sul, Inho; Cho, Boklae

    2017-02-01

    The performance of an electron gun is evaluated in terms of the gun brightness. The brightness of an electron gun is typically measured by dividing the angular current density by the virtual source area. An electron gun brightness measurement system was constructed without an electron lens. The system consists of movable apertures (∅ 30, 50, 100, 200 μ m ), a Faraday cup, and a phosphor screen. The Faraday cup is employed to measure the angular current density. The electron beam passes through an aperture and its shade is projected onto the phosphor screen. The virtual source position is determined by measuring the displacement of the aperture shade made by the movement of the aperture. The blurring width of the edge of the shadow on the screen is measured by a charged-coupled device camera to calculate the virtual source size. Brightness values of a tungsten filament electron gun were obtained and compared to reported values.

  19. Design and performance of a 30 KV electron gun with ten independent cathodes & a magnetic lens.

    Energy Technology Data Exchange (ETDEWEB)

    Rudys, Joseph Matthew; Reed, Kim Warren

    2006-08-01

    Measurements on a 30 kV electron gun with ten independent cathodes, operating in a 6.5 Tesla (T) magnetic field are presented. An earlier paper covered the design of this electron gun [1]. Experimental results are compared to model predictions. Beam current is compared to theoretical space charge limited flow.

  20. Phase II Final Report Computer Optimization of Electron Guns

    Energy Technology Data Exchange (ETDEWEB)

    R. Lawrence Ives; Thuc Bui; Hien Tran; Michael Read; Adam Attarian; William Tallis

    2011-04-15

    This program implemented advanced computer optimization into an adaptive mesh, finite element, 3D, charged particle code. The routines can optimize electron gun performance to achieve a specified current, beam size, and perveance. It can also minimize beam ripple and electric field gradients. The magnetics optimization capability allows design of coil geometries and magnetic material configurations to achieve a specified axial magnetic field profile. The optimization control program, built into the charged particle code Beam Optics Analyzer (BOA) utilizes a 3D solid modeling package to modify geometry using design tables. Parameters within the graphical user interface (currents, voltages, etc.) can be directly modified within BOA. The program implemented advanced post processing capability for the optimization routines as well as the user. A Graphical User Interface allows the user to set up goal functions, select variables, establish ranges of variation, and define performance criteria. The optimization capability allowed development of a doubly convergent multiple beam gun that could not be designed using previous techniques.

  1. The Use of an Electron Microchannel as a Self-Extracting and Focusing Plasma Cathode Electron Gun

    Science.gov (United States)

    Cornish, S.; Khachan, J.

    2016-02-01

    A new and simple type of electron gun is presented. Unlike conventional electron guns, which require a heated filament or extractor, accelerator and focusing electrodes, this gun uses the collimated electron microchannels of an inertial electrostatic confinement (IEC) discharge to achieve the same outcome. A cylindrical cathode is placed coaxially within a cylindrical anode to create the discharge. Collimated beams of electrons and fast neutrals emerge along the axis of the cylindrical cathode. This geometry isolates one of the microchannels that emerge in a negatively biased IEC grid. The internal operating pressure range of the gun is 35-190 mTorr. A small aperture separates the gun from the main vacuum chamber in order to achieve a pressure differential. The chamber was operated at pressures of 4-12 mTorr. The measured current produced by the gun was 0.1-3 mA (0.2-14 mA corrected measurement) for discharge currents of 1-45 mA and discharge voltages of 0.5-12 kV. The collimated electron beam emerges from the aperture into the vacuum chamber. The performance of the gun is unaffected by the pressure differential between the vacuum chamber and the gun. This allows the aperture to be removed and the chamber pressure to be equal to the gun pressure if required.

  2. An ultrafast nanotip electron gun triggered by grating-coupled surface plasmons

    Science.gov (United States)

    Schröder, Benjamin; Sivis, Murat; Bormann, Reiner; Schäfer, Sascha; Ropers, Claus

    2015-12-01

    We demonstrate multiphoton photoelectron emission from gold nanotips induced by nanofocusing surface plasmons, resonantly excited on the tip shaft by a grating coupler. The tip is integrated into an electron gun assembly, which facilitates control over the spatial emission sites and allows us to disentangle direct grating emission from plasmon-triggered apex emission. The nanoscale source size of this electron gun concept enables highly coherent electron pulses with applications in ultrafast electron imaging and diffraction.

  3. An ultrafast nanotip electron gun triggered by grating-coupled surface plasmons

    Energy Technology Data Exchange (ETDEWEB)

    Schröder, Benjamin; Sivis, Murat; Bormann, Reiner; Schäfer, Sascha; Ropers, Claus, E-mail: cropers@gwdg.de [4th Physical Institute - Solids and Nanostructures, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

    2015-12-07

    We demonstrate multiphoton photoelectron emission from gold nanotips induced by nanofocusing surface plasmons, resonantly excited on the tip shaft by a grating coupler. The tip is integrated into an electron gun assembly, which facilitates control over the spatial emission sites and allows us to disentangle direct grating emission from plasmon-triggered apex emission. The nanoscale source size of this electron gun concept enables highly coherent electron pulses with applications in ultrafast electron imaging and diffraction.

  4. Short Electron Bunch Generation Using Single-Cycle Ultrafast Electron Guns

    CERN Document Server

    Fallahi, Arya; Yahaghi, Alireza; Arrieta, Miguel; Kärtner, Franz X

    2016-01-01

    We introduce a solution for producing ultrashort ($\\sim$fs) high charge ($\\sim$pC) from ultra-compact guns utilizing single-cycle THz pulses. We show that the readily available THz pulses with energies as low as 20 ?J are sufficient to generate multi-10 keV electron bunches. Moreover, It is demonstrated that THz energies of 2mJ are sufficient to generate relativistic electron bunches with higher than 2 MeV energy. The high acceleration gradients possible in the structures provide 30 fs electron bunches at 30 keV energy and 45 fs bunches at 2 MeV energy. These structures will underpin future devices for strong field THz physics in general and miniaturized electron guns, in which the high fields combined with the short pulse duration enable electron beams with ultrahigh brightness.

  5. Short electron bunch generation using single-cycle ultrafast electron guns

    Science.gov (United States)

    Fallahi, Arya; Fakhari, Moein; Yahaghi, Alireza; Arrieta, Miguel; Kärtner, Franz X.

    2016-08-01

    We introduce a solution for producing ultrashort (˜fs ) high charge (˜pC ) from ultracompact guns utilizing single-cycle THz pulses. We show that the readily available THz pulses with energies as low as 20 μ J are sufficient to generate multi-10 keV electron bunches. Moreover, it is demonstrated that THz energies of 2 mJ are sufficient to generate relativistic electron bunches with higher than 2 MeV energy. The high acceleration gradients possible in the structures provide 30 fs electron bunches at 30 keV energy and 45 fs bunches at 2 MeV energy. These structures will underpin future devices for strong field THz physics in general and miniaturized electron guns, in which the high fields combined with the short pulse duration enable electron beams with ultrahigh brightness.

  6. Low emittance electron beam formation with a 17 GHz RF gun

    Directory of Open Access Journals (Sweden)

    W. J. Brown

    2001-08-01

    Full Text Available We report on electron beam quality measurement results from the Massachusetts Institute of Technology 17 GHz RF gun experiment. The 1.5 cell RF gun uses a solenoid for emittance compensation. It has produced bunch charges up to 0.1 nC with beam energies up to 1 MeV. The normalized rms emittance of the beam after 35 cm of transport from the gun has been measured by a slit technique to be 3π mm mrad for a 50 pC bunch. This agrees well with PARMELA simulations at these beam energies. At the exit of the electron gun, we estimate the emittance to be about 1π mm mrad, which corresponds to a beam brightness of about 80 A/(π mm mrad^{2}. Improved beam quality should be possible with a higher energy output electron beam from the gun.

  7. 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...

  8. Status of High Intensity Polarized Electron Gun at Mit-Bates

    Science.gov (United States)

    Tsentalovich, E.; Bessuille, J.; Tiunov, M.

    2011-01-01

    MIT-Bates, in collaboration with BNL, has developed a high intensity polarized electron gun for the eRHIC project. The gun implements large area cathode, ring-shaped beam and active cathode cooling. The paper describes the current status of the project.

  9. Generation and measurement of sub-picosecond electron bunch in photocathode rf gun

    OpenAIRE

    Li, Weiwei; He, Zhiagng; Jia, Qika

    2013-01-01

    We consider a scheme to generate sub-picosecond electron bunch in the photocathode rf gun by improving the acceleration gradient in the gun, suitably tuning the bunch charge, the laser spot size and the acceleration phase, and reducing the growth of transverse emittance by laser shaping. A nondestructive technique is also reported to measure the electron bunch length, by measuring the high-frequency spectrum of wakefield radiation which is caused by the passage of a relativistic electron bunc...

  10. Electron bunch structure in energy recovery linac with high-voltage dc photoelectron gun

    Science.gov (United States)

    Saveliev, Y. M.; Jackson, F.; Jones, J. K.; McKenzie, J. W.

    2016-09-01

    The internal structure of electron bunches generated in an injector line with a dc photoelectron gun is investigated. Experiments were conducted on the ALICE (accelerators and lasers in combined experiments) energy recovery linac at Daresbury Laboratory. At a relatively low dc gun voltage of 230 kV, the bunch normally consisted of two beamlets with different electron energies, as well as transverse and longitudinal characteristics. The beamlets are formed at the head and the tail of the bunch. At a higher gun voltage of 325 kV, the beam substructure is much less pronounced and could be observed only at nonoptimal injector settings. Experiments and computer simulations demonstrated that the bunch structure develops during the initial beam acceleration in the superconducting rf booster cavity and can be alleviated either by increasing the gun voltage to the highest possible level or by controlling the beam acceleration from the gun voltage in the first accelerating structure.

  11. JAERI 200 kV Electron Gun with an NEA-GaAs Photocathode

    CERN Document Server

    Nishitani, Tomohiro; Kikuzawa, Nobuhiro; John Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki; Sawamura, Masaru; Yamauchi, T

    2004-01-01

    The GaAs photocathode with negative electron affinity surface (NEA-GaAs) has been expected to be low emittance (<0.5 πmm・mrad) electron beam source. In order to generate low emittance electron beam required from ERL-FEL, we have started the developmental program of a 200keV electron gun with the NEA-GaAs photocathode for the first time in JAERI. An NEA surface has the problem that lifetime is limited by gun vacuum condition and by ion back bombardment between anode- and cathode-electrode. In order to long an NEA surface lifetime, the JAERI 200keV electron gun system consists of a 200kV DC-gun chamber on extreme high vacuum condition and an NEA activation chamber with load-lock system.

  12. Model of control of glow discharge electron gun current for microelectronics production applications

    Science.gov (United States)

    Denbnovetsky, S. V.; Melnyk, V. I.; Melnyk, I. V.; Tugay, B. A.

    2003-04-01

    The problems of simulation of discharge current control and its gas-dynamic stabilization for technological glow discharge electron guns with a cold cathode are considered in a paper. Such guns are successfully operated in soft vacuum and can be used in modern microelectronic technologies for providing of thermal operations with using different technological gases including active ones. The results of theoretical and experimental investigation of automatic control system of current of electron gun which were used for deposition of coatings in reactive gas medium are presented in article. Time of regulation for considered system did not exceed 400 ms. Is proved, that the automatic control of a current of a glow discharge electron gun by pressure variation its volume is effective on all operation range of pressure, and the minimum time of a current regulation can be tens -- hundred of ms, and this fact is allow to use in the majority of technological operations for microelectronic production.

  13. Development of compact gas treatment system using secondary emission electron gun

    CERN Document Server

    Watanabe, M; Okino, A; Ko, K C; Hotta, E; Watanabe, Masato; Wang, Yu; Okino, Akitoshi; Ko, Kwang-Cheol; Hotta, Eiki

    2004-01-01

    It is well known that the non-thermal plasma processes using electrical discharge or electron beam are effective for the environmental pollutant removal. Especially, the electron beam can efficiently remove pollutant, because a lot of radicals which are useful to remove pollutant can be easily produced by high-energy electrons. We have developed a compact 100kV secondary emission electron gun to apply NOX removal. The device offers several inherent advantages such as compact in size, wide and uniform electron beam. Besides, the device offers good capability in high repetition rate pulsed operation with easy control compared with glow discharge or field emission control cathode guns. In present study, the NOX removal characteristics have been studied under the increased gun voltage, varied pulsed electron beam parameters such as current density and pulse width as well as gas flow rate. The experimental results indicate a better NOX removal efficiency comparing to other high-energy electron beam and electrical ...

  14. Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source.

    Science.gov (United States)

    Pikin, A; Beebe, E N; Raparia, D

    2013-03-01

    Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 ÷ 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 ÷ 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

  15. Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A.; Beebe, E. N.; Raparia, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2013-03-15

    Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 Division-Sign 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 Division-Sign 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

  16. Heat load of a GaAs photocathode in an SRF electron gun

    Institute of Scientific and Technical Information of China (English)

    WANG Er-Dong; ZHAO Kui; J(o)rg Kewisch; Ilan Ben-Zvi; Andrew Burrill; Trivini Rao; WU Qiong; Animesh Jain; Ramesh Gupta; Doug Holmes

    2011-01-01

    A great deal of effort has been made over the last decades to develop a better polarized electron source for high energy physics. Several laboratories operate DC guns with a gallium arsenide photocathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved by using a superconducting radio frequency (SRF) electron gun, which delivers beams of a higher brightness than that from DC guns because the field gradient at the cathode is higher. SRF guns with metal and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since a bulk gallium arsenide (GaAs) photocathode is normal conducting, a problem arises from the heat load stemming from the cathode. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and verification by measuring the quality factor of the gun with and without the cathode at 2 K. We simulate heat generation and flow from the GaAs cathode using the ANSYS program. By following the findings with the heat load model, we designed and fabricated a new cathode holder (plug) to decrease the heat load from GaAs.

  17. Investigations and applications of field- and photo-emitted electron beams from a radio frequency gun

    Science.gov (United States)

    Panuganti, Sriharsha

    Production of quality electron bunches using efficient 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 field emission inside an RF gun installed at Fermilab's High Brightness Electron Source Laboratory (HBESL). Specifically, we study and characterize second-order nonlinear photoemission from a Cesium Telluride (Cs2Te) semiconductor photocathode, and field emission from carbon based cathodes including diamond field 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 filled ellipsoidal bunches and temporally-shaped electron beams from the Cs 2Te photocathode.

  18. Note: Design and development of improved indirectly heated cathode based strip electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Namita; Patil, D. S.; Dasgupta, K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bade, Abhijeet; Tembhare, G. U. [Department of Mechanical Engineering, Veermata Jijabai Technological Institute, Matunga, Mumbai 400 019 (India)

    2015-02-15

    An improved design of indirectly heated solid cathode based electron gun (200 kW, 45 kV, 270° bent strip type electron gun) has been presented. The solid cathode is made of thoriated tungsten, which acts as an improved source of electron at lower temperature. So, high power operation is possible without affecting structural integrity of the electron gun. The design issues are addressed based on the uniformity of temperature on the solid cathode and the single long filament based design. The design approach consists of simulation followed by extensive experimentation. In the design, the effort has been put to tailor the non-uniformity of the heat flux from the filament to the solid cathode to obtain better uniformity of temperature on the solid cathode. Trial beam experiments have been carried out and it is seen that the modified design achieves one to one correspondence of the solid cathode length and the electron beam length.

  19. 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.

  20. HOMs of the SRF Electron Gun Cavity in the BNL ERL

    Science.gov (United States)

    Hahn, H.; Ben-Zvi, I.; Belomestnykh, S.; Hammons, L.; Litvinenko, V.; Than, Y. R.; Todd, R.; Weiss, D.; Xu, Wencan

    The Brookhaven Energy Recovery Linac (ERL) is operated as an R&D test bed for high-current, low emittance electron beams. It comprises a superconducting five-cell cavity and a half-cell superconducting RF photo-injector electron gun. The ERL is undergoing commissioning with focus on the performance of the electron gun, not the least on the cavity Higher Order Modes (HOM). Among the various alternative solutions, a beam tube damper based on a layer of ferrite tiles was adopted for the five-cell accelerator cavity. For the gun, a ceramic-ferrite damper consisting of a lossless ceramic cylinder surrounded by damping ferrite tiles has been investigated. This design is innovative in its damper approach and combines a variety of goals including broadband HOM damping and protection of the superconducting cavity vacuum from potential damage by the separately cooled absorber. In this paper the empirical performance of an installed ceramic-ferrite damper is described by the Q reduction of a few selected gun cavity resonances. The theoretical coupling impedance presented to a traversing beam is numerically analyzed in terms of radial waveguide modes in the damper section. Strong damping of the gun cavity HOMs by the fundamental power coupler (FPC) is found and discussed. Finally, the measured Q-values of the operational gun cavity without the ceramic-ferrite damper at superconducting temperatures are presented

  1. Design of spherical electron gun for ultra high frequency, CW power inductive output tube

    Energy Technology Data Exchange (ETDEWEB)

    Kaushik, Meenu, E-mail: mkceeri@gmail.com; Joshi, L. M., E-mail: lmj1953@gmail.com [Microwave Tubes Division, CSIR-Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan (India); Academy of Scientific and Innovative Research (AcSIR), New Delhi (India)

    2016-03-09

    Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

  2. Design of spherical electron gun for ultra high frequency, CW power inductive output tube

    Science.gov (United States)

    Kaushik, Meenu; Joshi, L. M.

    2016-03-01

    Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

  3. System for transporting an electron beam to the atmosphere for a gun with a plasma emitter

    Science.gov (United States)

    Kornilov, S. Yu.; Rempe, N. G.; Shidlovskiy, S. V.

    2016-06-01

    We report on the results of simulation of the gas flow in a gun with a plasma emitter and in the system for extracting the electron beam to the atmosphere, constructed on the basis of standard gasdynamic windows (GDWs). The design of the gun and GDWs is described. Calculations are performed for a pressure of about 10-3 Torr in the electron beam generation range. It is shown that the pressure drop to the atmospheric pressure in the system of electron beam extraction to the atmosphere can be ensured by two GDW stages evacuated by pumps with optimal performance.

  4. High-current electron gun with a planar magnetron integrated with an explosive-emission cathode

    Science.gov (United States)

    Kiziridi, P. P.; Ozur, G. E.

    2017-05-01

    A new high-current electron gun with plasma anode and explosive-emission cathode integrated with planar pulsed powered magnetron is described. Five hundred twelve copper wires 1 mm in diameter and 15 mm in height serve as emitters. These emitters are installed on stainless steel disc (substrate) with 3-mm distance between them. Magnetron discharge plasma provides increased ion density on the periphery of plasma anode formed by high-current Penning discharge ignited within several milliseconds after starting of the magnetron discharge. The increased on the periphery ion density improves the uniformity of high-current electron beam produced in such an electron gun.

  5. Generation and measurement of sub-picosecond electron bunch in photocathode rf gun

    CERN Document Server

    Li, Weiwei; Jia, Qika

    2013-01-01

    We consider a scheme to generate sub-picosecond electron bunch in the photocathode rf gun by improving the acceleration gradient in the gun, suitably tuning the bunch charge, the laser spot size and the acceleration phase, and reducing the growth of transverse emittance by laser shaping. A nondestructive technique is also reported to measure the electron bunch length, by measuring the high-frequency spectrum of wakefield radiation which is caused by the passage of a relativistic electron bunch through a channel surrounded by a dielectric.

  6. Electron gun with off-axis beam injection for a race-track microtron

    Energy Technology Data Exchange (ETDEWEB)

    Aloev, A.V. [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Carrillo, D. [CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Kubyshin, Yu.A., E-mail: iouri.koubychine@upc.ed [Institute of Energy Technologies, Technical University of Catalonia, Campus Sud, Av. Diagonal 647, 08028 Barcelona (Spain); Pakhomov, N.I.; Shvedunov, V.I. [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation)

    2010-12-01

    A miniature 12 MeV race-track microtron for medical applications is under construction at the Technical University of Catalonia in collaboration with several Spanish centers and companies and the Skobeltsyn Institute of Nuclear Physics of the Moscow State University. As a source of electrons a compact 3D on-axis electron gun with an off-axis cathode has been designed to allow a direct and efficient injection into the accelerating structure. Its prototype has been built and successfully tested. Results of the electron gun design simulations and of the prototype performance are herein described.

  7. Heat load of a GaAs photocathode in an SRF electron gun

    Institute of Scientific and Technical Information of China (English)

    王尔东; 赵夔; JSrg Kewisch; Ilan Ben-Zvi; Andrew Burrill; Trivini Rao; 吴琼; Animesh Jain; Ramesh Gupta; Doug Holmes

    2011-01-01

    A great deal of effort has been made over the last decades to develop a better polarized electron source for high energy physics. Several laboratories operate DC guns with a gallium arsenide photocathode, which yield a highly polarized electron beam. Howe

  8. Development of Grid Control Electron Gun for Multi-energy Irradiation Accelerator

    Institute of Scientific and Technical Information of China (English)

    HAN; Guang-wen; ZHU; Zhi-bin; WANG; Shu-xian

    2012-01-01

    <正>In the project of multi-energy electron irradiation accelerator, It is necessary to adjust the electron beam pulse inject to the accelerating tube. Under the same conditions of the injection energy, the grid controlled electron gun was used in the accelerator. Using cathode-grid assembly, after the simulation of electron optics program design, we manufactured focus electrode, the anode, and built an experiment

  9. Design and implementation of a fs-resolved transmission electron microscope based on thermionic gun technology

    Science.gov (United States)

    Piazza, L.; Masiel, D. J.; LaGrange, T.; Reed, B. W.; Barwick, B.; Carbone, Fabrizio

    2013-09-01

    In this paper, the design and implementation of a femtosecond-resolved ultrafast transmission electron microscope is presented, based on a thermionic gun geometry. Utilizing an additional magnetic lens between the electron acceleration and the nominal condenser lens system, a larger percentage of the electrons created at the cathode are delivered to the specimen without degrading temporal, spatial and energy resolution significantly, while at the same time maintaining the femtosecond temporal resolution. Using the photon-induced near field electron microscopy effect (PINEM) on silver nanowires the cross-correlation between the light and electron pulses was measured, showing the impact of the gun settings and initiating laser pulse duration on the electron bunch properties. Tuneable electron pulses between 300 fs and several ps can be obtained, and an overall energy resolution around 1 eV was achieved.

  10. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Energy Technology Data Exchange (ETDEWEB)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  11. Design and analysis of 5045 S-band klystron DC electron gun

    CERN Document Server

    Rehman, Abdul; Zhou, Z

    2015-01-01

    The design and performance analysis of DC electron gun for 5045 S-band klystron has been worked out using SLAC beam trajectory program (EGUN) and Computer Simulation Technology Particle Studio (CST-PS), Codes. Specifications of electron gun were focused on beam; current, perveance, size and emittance. Optimized beam; current, perveance, diameter and emittance were 414.00A, 2.00uP, 26.82 mm and 103.10 pi mm mrad, respectively. Furthermore, the optimized characteristic parameters of the gun were also calculated and compared with the simulated and experimental values which were in agreement. Accuracy of simulation was verified by comparison of emitted beam current which has error of zero percent.

  12. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Science.gov (United States)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  13. A CW normal-conductive RF gun for free electron laser and energy recovery linac applications

    Science.gov (United States)

    Baptiste, K.; Corlett, J.; Kwiatkowski, S.; Lidia, S.; Qiang, J.; Sannibale, F.; Sonnad, K.; Staples, J.; Virostek, S.; Wells, R.

    2009-02-01

    Currently proposed energy recovery linac and high average power free electron laser projects require electron beam sources that can generate up to ˜1 nC bunch charges with less than 1 mm mrad normalized emittance at high repetition rates (greater than ˜1 MHz). Proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose an approach for a gun fully based on mature RF and mechanical technology that greatly diminishes many of such complications. The concepts for such a source as well as the present RF and mechanical design are described. Simulations that demonstrate the beam quality preservation and transport capability of an injector scheme based on such a gun are also presented.

  14. A CW normal-conductive RF gun for free electron laser and energy recovery linac applications

    Energy Technology Data Exchange (ETDEWEB)

    Baptiste, K.; Corlett, J.; Kwiatkowski, S.; Lidia, S.; Qiang, J. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Sannibale, F. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States)], E-mail: fsannibale@lbl.gov; Sonnad, K.; Staples, J.; Virostek, S.; Wells, R. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States)

    2009-02-01

    Currently proposed energy recovery linac and high average power free electron laser projects require electron beam sources that can generate up to {approx}1nC bunch charges with less than 1 mm mrad normalized emittance at high repetition rates (greater than {approx}1MHz). Proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose an approach for a gun fully based on mature RF and mechanical technology that greatly diminishes many of such complications. The concepts for such a source as well as the present RF and mechanical design are described. Simulations that demonstrate the beam quality preservation and transport capability of an injector scheme based on such a gun are also presented.

  15. A CW normal-conductive RF gun for free electron laser and energy recovery linac applications

    Energy Technology Data Exchange (ETDEWEB)

    Baptiste, Kenneth; Corlett, John; Kwiatkowski, Slawomir; Lidia, Steven; Qiang, Ji; Sannibale, Fernando; Sonnad, Kiran; Staples, John; Virostek, Steven; Wells, Russell

    2008-10-08

    Currently proposed energy recovery linac and high average power free electron laser projects require electron beam sources that can generate up to {approx} 1 nC bunch charges with less than 1 mmmrad normalized emittance at high repetition rates (greater than {approx} 1 MHz). Proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose an approach for a gun fully based on mature RF and mechanical technology that greatly diminishes many of such complications. The concepts for such a source as well as the present RF and mechanical design are described. Simulations that demonstrate the beam quality preservation and transport capability of an injector scheme based on such a gun are also presented.

  16. CEBAF 200 kV Inverted Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-01

    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&D stud­ies lead­ing to­ward a pro­duc­tion 200keV GaAs pho­to­gun for CEBAF will be pre­sent­ed.

  17. High Average Current Electron Guns for High-Power FELs

    Science.gov (United States)

    2009-12-09

    FELs 10 Appendix B: Thermionic Injectors 11 Appendix C: Grid Fields and Bunch Emittance 13 Appendix D: PARMELA Simulation of an IOT Gun 16...Inductive Output Tube ( IOT ) amplifiers [32-34] and can generate average currents of ~1 A, peak currents of ~ 5-10 A, cathode-anode voltages of ~ 35...of grid wires, centered at z = zG and x = ±a, ±3a, ±5a, ..., is given by <D(JC,Z) = - X n = ±l.±3. Fa(x,z) Gn(x,z) ( C3 ) where *0 = (1 / 2

  18. Thermocathode radio-frequency gun for the Budker Institute of Nuclear Physics free-electron laser

    Science.gov (United States)

    Volkov, V.; Getmanov, Ya.; Kenjebulatov, E.; Kolobanov, E.; Krutikhin, S.; Kurkin, G.; Ovchar, V.; Petrov, V. M.; Sedlyarov, I.

    2016-12-01

    A radio-frequency (RF) gun for a race-track microtron-recuperator injector driving the free-electron laser (FEL) (Budker Institute of Nuclear Physics) is being tested at a special stand. Electron bunches of the RF gun have an energy of up to 300 keV and a repetition rate of up to 90 MHz. The average electro-beam current can reach 100 mA in the continuous operation regime. The advantages of the new injector are as follows: long lifetime of the cathode for high average beam current; simple scheme of longitudinal beam bunching, which does not require an additional bunching resonator in the injector; absence of dark-current contamination of the injector beam; and comfortable RF gun operation due to the absence of a high potential of 300 kV at the cathode control circuits. In this study we describe the RF gun design, present the main characteristics of the injector with the RF gun, and give the results of testing.

  19. Single-side electron multipacting at the photocathode in rf guns

    Directory of Open Access Journals (Sweden)

    Jang-Hui Han

    2008-01-01

    Full Text Available Multiple electron impacting (multipacting can take place in rf fields when the rf components are composed of materials with a secondary electron yield greater than one. In rf gun cavities, multipacting may change the properties of the vacuum components or even damage them. First systematic measurements of the multipacting occurring in a photocathode rf gun were made at the Fermilab/NICADD Photoinjector Laboratory in 2000. The multipacting properties were found to depend on the cathode material and the solenoid field configuration. In this study, we measure the multipacting properties in more detail and model the secondary electron generation for numerical simulation. Measurements and simulations for the photoinjectors at Fermilab and DESY are compared. The multipacting takes place at the photocathode in rf guns and is categorized as single-side multipacting. In a low rf field, the electrons emitted from the cathode area do not leave the gun cavity within one rf cycle and have an opportunity to travel back and hit the cathode. The solenoid field distribution in the vicinity of the cathode changes the probability of electron bombardment of the cathode and makes a major contribution to the multipacting behavior.

  20. 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.

  1. 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.

  2. Stability measurements of the electron gun for the KATRIN rear section

    Energy Technology Data Exchange (ETDEWEB)

    Ebenhoech, Sylvia [Karlsruhe Institute of Technology (KIT) (Germany). Institute for Technical Physics (ITEP), Tritium Laboratory Karlsruhe (TLK); Collaboration: KATRIN-Collaboration

    2016-07-01

    The aim of the KArlsruhe TRItium Neutrino (KATRIN) experiment is to determine the antineutrino mass with a sensitivity of 0.2 eV (90 % C.L.) by high-precision spectroscopy close to the tritium beta decay endpoint at 18.6 keV. To achieve the sensitivity aim both statistical and systematic uncertainties must be minimized. One contribution to the systematic error are uncertainties in the column density of the tritium source or in the source activity. In order to detect and monitor changes in the tritium source the Rear Section, which is integrated at the rear end of the KATRIN setup, is used. The Rear Section includes an angular selective electron gun (e-gun) based on the photoelectric effect. With the e-gun it will be possible e.g. to achieve a precise calibration of the column source density. To achieve the requirements on the e-gun a stable UV light source is essential to produce photoelectrons. The presentation focuses on the setup of the e-gun and intensity stability measurements of the UV light source setup.

  3. Optimizing the CEBAF Injector for Beam Operation with a Higher Voltage Electron Gun

    CERN Document Server

    Hannon, F E; Kazimi, R

    2011-01-01

    Recent developments in the DC gun technology used at CEBAF have allowed an increase in operational voltage from 100kV to 130kV. In the near future this will be extended further to 200kV with the purchase of a new power supply. The injector components and layout at this time have been designed specifically for 100kV operation. It is anticipated that with an increase in gun voltage and optimization of the layout and components for 200kV operation, that the electron bunch length and beam brightness can be improved upon. This paper explores some upgrade possibilities for a 200kV gun CEBAF injector through beam dynamic simulations.

  4. High power microwave generation using a repetitive electron gun with a ferroelectric cathode

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Y.; Ivers, J.D.; Nation, J.A.; Wang, P. Golkowski, C.; Flechtner, D.; Schaechter, L.

    1999-07-01

    An electron gun using a ferroelectric cathode driven by a ferrite core transformer-pulse line system produces a 500kV, 50--200A, 250ns long beam. The beam is used to drive an X-band amplifier. The amplifier consists of a single stage disk loaded type structure. At the end of the amplifier, a coaxial mode converter is used to decouple the beam from the microwave radiation. The amplifier operates at a repetition rate of 0.1Hz. The beam emission is controlled by a voltage pulse applied to the back of the ferroelectric. Results will be reported on the amplifier performance characteristics with a 50A beam and the results compared with simulation data. An improved gun design, which gives a uniform cross section 200A beam is being built, and early results obtained, using the high current gun, will also be presented.

  5. Communication: Effects of thermionic-gun parameters on operating modes in ultrafast electron microscopy

    Directory of Open Access Journals (Sweden)

    Erik Kieft

    2015-09-01

    Full Text Available Ultrafast electron microscopes with thermionic guns and LaB6 sources can be operated in both the nanosecond, single-shot and femtosecond, single-electron modes. This has been demonstrated with conventional Wehnelt electrodes and absent any applied bias. Here, by conducting simulations using the General Particle Tracer code, we define the electron-gun parameter space within which various modes may be optimized. The properties of interest include electron collection efficiency, temporal and energy spreads, and effects of laser-pulse duration incident on the LaB6 source. We find that collection efficiencies can reach 100% for all modes, despite there being no bias applied to the electrode.

  6. High-voltage testing of a 500-kV dc photocathode electron gun

    Science.gov (United States)

    Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Muto, Toshiya; Yamamoto, Masahiro; Honda, Yosuke; Miyajima, Tsukasa; Iijima, Hokuto; Kuriki, Masao; Kuwahara, Makoto; Okumi, Shoji; Nakanishi, Tsutomu

    2010-03-01

    A high-voltage dc photocathode electron gun was successfully conditioned up to a voltage of 550 kV and a long-time holding test for 8 h was demonstrated at an acceleration voltage of 500 kV. The dc photocathode electron gun is designed for future light sources based on energy-recovery linac and consists of a Cockcroft-Walton generator, a segmented cylindrical ceramic insulator, guard-ring electrodes, a support-rod electrode, a vacuum chamber, and a pressurized insulating gas tank. The segmented cylindrical ceramic insulator and the guard-ring electrodes were utilized to prevent any damage to the insulator from electrons emitted by the support-rod electrode.

  7. High voltage threshold for stable operation in a dc electron gun

    Science.gov (United States)

    Yamamoto, Masahiro; Nishimori, Nobuyuki

    2016-07-01

    We report clear observation of a high voltage (HV) threshold for stable operation in a dc electron gun. The HV hold-off time without any discharge is longer than many hours for operation below the threshold, while it is roughly 10 min above the threshold. The HV threshold corresponds to the minimum voltage where discharge ceases. The threshold increases with the number of discharges during HV conditioning of the gun. Above the threshold, the amount of gas desorption per discharge increases linearly with the voltage difference from the threshold. The present experimental observations can be explained by an avalanche discharge model based on the interplay between electron stimulated desorption (ESD) from the anode surface and subsequent secondary electron emission from the cathode by the impact of ionic components of the ESD molecules or atoms.

  8. Electron gun for a multiple beam klystron with magnetic compression of the electron beams

    Science.gov (United States)

    Ives, R. Lawrence; Tran, Hien T; Bui, Thuc; Attarian, Adam; Tallis, William; David, John; Forstall, Virginia; Andujar, Cynthia; Blach, Noah T; Brown, David B; Gadson, Sean E; Kiley, Erin M; Read, Michael

    2013-10-01

    A multi-beam electron gun provides a plurality N of cathode assemblies comprising a cathode, anode, and focus electrode, each cathode assembly having a local cathode axis and also a central cathode point defined by the intersection of the local cathode axis with the emitting surface of the cathode. Each cathode is arranged with its central point positioned in a plane orthogonal to a device central axis, with each cathode central point an equal distance from the device axis and with an included angle of 360/N between each cathode central point. The local axis of each cathode has a cathode divergence angle with respect to the central axis which is set such that the diverging magnetic field from a solenoidal coil is less than 5 degrees with respect to the projection of the local cathode axis onto a cathode reference plane formed by the device axis and the central cathode point, and the local axis of each cathode is also set such that the angle formed between the cathode reference plane and the local cathode axis results in minimum spiraling in the path of the electron beams in a homogenous magnetic field region of the solenoidal field generator.

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

    Energy Technology Data Exchange (ETDEWEB)

    A.M.M. Todd; A. Ambrosio; H. Bluem; V. Christina; M.D. Cole; M. Falletta; D. Holmes; E. Peterson; J. Rathke; T. Schultheiss; R. Wong; I. Ben-Zvi; A. Burrill; R. Calaga; P. Cameron; X.Y. Chang; H. Hahn; D. Kayran; J. Kewisch; V. Litvinenko; G.T. McIntyre; T. Nicoletti; J. Rank; T. Rao; J. Scaduto; K.-C. Wu; A. Zaltsman; Y. Zhao; S.V. Benson; E. Daly; D. Douglas; H.F.D. Dylla; L. W. Funk; C. Hernandez-Garcia; J. Hogan; P. Kneisel; J. Mammosser; G. Neil; H.L. Phillips; J.P. Preble; R.A. Rimmer; C.H. Rode; T. Siggins; T. Whitlach; M. Wiseman; I.E. Campisi; P. Colestock; J.P. Kelley; S.S. Kurennoy; D.C. Nguyen; W. Reass; D. Rees; S.J. Russell; D.L. Schrage; R.L. Wood; D. Janssen; J.W. Lewellen; J.S. Sekutowicz; L.M. Young

    2005-05-01

    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 Ampere will be tested to 0.5 Ampere at the Brookhaven National Laboratory in 2006. The fabrication status, schedule and projected performance for each of these state-of-the-art injector programs will be presented.

  10. 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...

  11. 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.

  12. Low-cost electron-gun pulser for table-top maser experiments

    Science.gov (United States)

    Grinberg, V.; Jerby, E.; Shahadi, A.

    1995-04-01

    A simple 10 kV electron-gun pulser for small-scale maser experiments is presented. This low-cost pulser has operated successfully in various table-top cyclotron-resonance maser (CRM) and free-electron maser (FEM) experiments. It consists of a low-voltage capacitor bank, an SCR control circuit and a transformer bank (car ignition coils) connected directly to the e-gun. The pulser produces a current of 3 A at 10 kV voltage in a Gaussian like shape of 1 ms pulse width. The voltage sweep during the pulse provides a useful tool to locate resonances of CRM and FEM interactions. Analytical expressions for the pulser design and experimental measurements are presented.

  13. Performance evaluation of self-breakdown-based single-gap plasma cathode electron gun

    Indian Academy of Sciences (India)

    Niraj Kumar; Nalini Pareek; Udit Narayan Pal; Deepak Kumar Verma; Jitendra Prajapati; Mahesh Kumar; Bharat Lal Meena; Ram Prakash

    2014-06-01

    This paper presents the experimental studies on self-breakdown-based single-gap plasma cathode electron (PCE) gun (5–20 kV/50–160 A) in argon, gas atmosphere and its performance evaluation based on particle-in-cell (PIC) simulation code `OOPIC-Pro’.The PCE-Gun works in conducting phase (low energy, high current) of pseudospark discharge. It produces an intense electron beam, which can propagate more than 200 mm in the drift space region without external magnetic field. The profile of this beam in the drift space region at different breakdown conditions (i.e., gas pressures and applied voltages) has been studied and the experimental results are compared with simulated values. It is demonstrated that ∼30% beam current is lost during the propagation possibly due to space charge neutralization and collisions with neutral particles and walls.

  14. Investigating the effect of electron emission pattern on RF gun beam quality

    Energy Technology Data Exchange (ETDEWEB)

    Rajabi, A. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of); Shokri, B., E-mail: b-shokri@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of)

    2016-05-11

    Thermionic radio frequency gun is one of the most promising choices to gain a high quality electron beam, used in the infrared free electron lasers and synchrotron radiation injectors. To study the quality of the beam in a compact electron source, the emission pattern effect on the beam dynamics should be investigated. In the presented work, we developed a 3D simulation code to model the real process of thermionic emission and to investigate the effect of emission pattern, by considering geometrical constraints, on the beam dynamics. According to the results, the electron bunch emittance varies considerably with the emission pattern. Simulation results have been validated via comparison with the well-known simulation codes such as ASTRA simulation code and CST microwave studio, as well as other simulation results in the literature. It was also demonstrated that by using a continuous wave laser beam for heating the cathode, the emission pattern full width at half maximum (FWHM) of the transverse emission distribution is proportional to FWHM of the Gaussian profile for the laser beam. Additionally, by using the developed code, the effect of wall structure around the cathode on the back bombardment effect has been studied. According to the results, for a stable operation of the RF gun, one should consider the nose cone in vicinity of the cathode surface to reduce the back-bombardment effect. - Highlights: • We developed a 3D code to simulate the beam dynamics of thermionic RF gun. • Te impact of the emission pattern on the beam dynamic was investigated. • Different emission pattern results different emittance in the gun exit. • Using a nosecone around the cathode adjacent wall reduces back bombardment effect.

  15. Solid-state pulse modulator using Marx generator for a medical linac electron-gun

    Science.gov (United States)

    Lim, Heuijin; Hyeok Jeong, Dong; Lee, Manwoo; Lee, Mujin; Yi, Jungyu; Yang, Kwangmo; Ro, Sung Chae

    2016-04-01

    A medical linac is used for the cancer treatment and consists of an accelerating column, waveguide components, a magnetron, an electron-gun, a pulse modulator, and an irradiation system. The pulse modulator based on hydrogen thyratron-switched pulse-forming network is commonly used in linac. As the improvement of the high power semiconductors in switching speed, voltage rating, and current rating, an insulated gate bipolar transistor has become the more popular device used for pulsed power systems. We propose a solid-state pulse modulator to generator high voltage by multi-stacked storage-switch stages based on the Marx generator. The advantage of our modulator comes from the use of two semiconductors to control charging and discharging of the storage capacitor at each stage and it allows to generate the pulse with various amplitudes, widths, and shapes. In addition, a gate driver for two semiconductors is designed to reduce the control channels and to protect the circuits. It is developed for providing the pulsed power to a medical linac electron-gun that requires 25 kV and 1 A as the first application. In order to improve the power efficiency and achieve the compactness modulator, a capacitor charging power supply, a Marx pulse generator, and an electron-gun heater isolated transformer are constructed and integrated. This technology is also being developed to extend the high power pulsed system with > 1 MW and also other applications such as a plasma immersed ion implantation and a micro pulse electrostatic precipitator which especially require variable pulse shape and high repetition rate > 1 kHz. The paper describes the design features and the construction of this solid-state pulse modulator. Also shown are the performance results into the linac electron-gun.

  16. Cathode Holder and Transfer Mechanism Design for Warm Cathode in SRF Electron Gun

    Science.gov (United States)

    2013-03-13

    not achieved (or if an increased gradient is obtainable), including an optimization of solenoidal field and laser spot size for different values of...guns for free electron laser applications. Since these programs are based on Niowave-fabricated, lower frequency quarter-wave structures, many...the solenoid and non-optimal solenoid strength. For example, Figure 13 shows the increase in emittance resulting from a horizontal dipole error in

  17. Multislit-Based Emittance Measurement of Electron Beam from a Photocathode Radio-Frequency Gun

    Institute of Scientific and Technical Information of China (English)

    YAN Li-Xin; DU Ying-Chao; XIANG Dao; LI Ren-Kai; QIAN Hou-Jun; HUANG Wen-Hui; TANG Chuan-Xiang; LIN Yu-Zheng; CHENG Jian-Ping

    2008-01-01

    Measurement of emittance for a space-charge dominated electron beam from a photocathode rf gun is performed by employing the multislit-based method at Accelerator Laboratory of Tsinghua University.We present the design considerations on the multislit system and the experimental results,with special attention to the study of space charge induced emittance growth.The experimental results are in reasonable agreement with the PARMELA simulations.

  18. Beam diagnostics for high quality electron beam emitted from photocathode rf-gun

    Science.gov (United States)

    Sakaue, Kazuyuki; Kudo, Norio; Moriyama, Ryo; Washio, Masakazu

    2006-03-01

    High quality electron beam generation using photocathode rf-gun system and beam diagnostic techniques have been developed at Waseda University. This system can generate up to 4.6 MeV low emittance and short bunch electron beam. For bunch length monitor, rf-kicker technique is able to streak the electron bunch directly, using transverse magnetic field on the beam orbit. This technique is able to observe the longitudinal profile of the bunch and to achieve higher resolution than streak camera method.

  19. Beam diagnostics for high quality electron beam emitted from photocathode rf-gun

    Energy Technology Data Exchange (ETDEWEB)

    Sakaue, Kazuyuki; Kudo, Norio; Moriyama, Ryo; Washio, Masakazu [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku Tokyo 169-8555 (Japan)

    2006-03-21

    High quality electron beam generation using photocathode rf-gun system and beam diagnostic techniques have been developed at Waseda University. This system can generate up to 4.6 MeV low emittance and short bunch electron beam. For bunch length monitor, rf-kicker technique is able to streak the electron bunch directly, using transverse magnetic field on the beam orbit. This technique is able to observe the longitudinal profile of the bunch and to achieve higher resolution than streak camera method.

  20. Optimization of operation parameters of 80-keV electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Dong; Lee, Yong Deok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kang, Heung Sik [Pohang Accelerator Laboratory, Pohang (Korea, Republic of)

    2014-06-15

    A Slowing Down Time Spectrometer (SDTS) system is a highly efficient technique for isotopic nuclear material content analysis. SDTS technology has been used to analyze spent nuclear fuel and the pyro-processing of spent fuel. SDTS requires an external neutron source to induce the isotopic fissile fission. A high intensity neutron source is required to ensure a high for a good fissile fission. The electron linear accelerator system was selected to generate proper source neutrons efficiently. As a first step, the electron generator of an 80-keV electron gun was manufactured. In order to produce the high beam power from electron linear accelerator, a proper beam current is required form the electron generator. In this study, the beam current was measured by evaluating the performance of the electron generator. The beam current was determined by five parameters: high voltage at the electron gun, cathode voltage, pulse width, pulse amplitude, and bias voltage at the grid. From the experimental results under optimal conditions, the high voltage was determined to be 80 kV, the pulse width was 500 ns, and the cathode voltage was from 4.2 V to 4.6 V. The beam current was measured as 1.9 A at maximum. These results satisfy the beam current required for the operation of an electron linear accelerator.

  1. Piercing and Tattoos

    Science.gov (United States)

    Piercings and tattoos are body decorations that go back to ancient times. Body piercing involves making a hole in the skin ... can be in other parts of the body. Tattoos are designs on the skin made with needles ...

  2. EGUN: An electron optics and gun design program

    Energy Technology Data Exchange (ETDEWEB)

    Herrmannsfeldt, W.B.

    1988-10-01

    The name EGUN has become commonly associated with the program also known as the SLAC Electron Trajectory Program. This document is an updated version of SLAC-226, published in 1979. The program itself has had substantial upgrading since then, but only a few new features are of much concern to the user. Most of the improvements are internal and are intended to improve speed or accuracy. EGUN is designed to compute trajectories of charged particles in electrostatic and magnetostatic fields, including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes, as well as used specified initial conditions. Either rectangular or cylindrical symmetry may be used. In the new jargon, the program is a 2-1/2 dimension code meaning 2-D in all fields and 3-D in all particle motion. A Poisson's Equation Solver is used to find the electrostatic fields by using difference equations derived from the boundary conditions. Magnetic fields are to be specified externally, by the user, by using one of several methods including data from another program or arbitrary configurations of coils. This edition of the documentation also covers the program EGN87c, which is a recently developed version of EGUN designed to be used on the newer models of personal computers, small main frames, work stations, etc. The EGN87c program uses the programming language C which is very transportable so the program should operate on any system that supports C. Plotting routines for most common PC monitors are included, and the capability to make hard copy plots on dot-matrix printer-plotters is provided. 18 refs., 7 figs.

  3. Electron Gun and Injector Designs for State-of-the-Art FELs

    CERN Document Server

    Blüm, H P; Christina, V; Cole, M D; Falletta, M; Holmes, D; Peterson, E; Rathke, J; Schultheiss, T; Todd, A M M; Wong, R

    2005-01-01

    Reliable, high-brightness, high-power injector operation is a critical technology issue for energy recovery linac drivers of high-power free electron lasers (FEL). Advanced Energy Systems is involved in three ongoing injector programs that target up to 0.5 Ampere current levels at emittance values consistent with the requirements of the FEL. One is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. A 748.5 MHz injector of this type is being assembled and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility (JLAB) beginning in 2007. The second approach being explored is a high-current normal-conducting RF photoinjector. A 700 MHz gun, presently under fabrication, will undergo thermal test in 2006 at Los Alamos National Laboratory (LANL). Finally, a half-cell 703.75 MHz SRF gun is presently being designed and will be tested to 0.5 Ampere at Brookhaven National Laboratory (BNL) in 2007. The status and projected performance for each of these injector projects is pr...

  4. Off-axis beam dynamics in rf-gun-based electron photoinjectors

    Science.gov (United States)

    Huang, R.; Mitchell, C.; Papadopoulos, C.; Qian, H.; Venturini, M.; Qiang, J.; Filippetto, D.; Staples, J.; Jia, Q.; Sannibale, F.

    2016-11-01

    The need to operate an rf-gun-based electron photoinjector with a beam emitted away from the cathode center can occur under various circumstances. First, in some cases the cathode can be affected by ion back-bombardment that progressively reduces the quantum efficiency (QE) in its center, making off-axis operation mandatory; second, in some cases the drive laser intensity can be sufficiently high to generate QE depletion in the cathode area illuminated by the laser, forcing off-axis operation; last, in cathodes with nonuniform QE distribution it could be convenient to operate off axis to exploit a better QE. However, operation in this mode may lead to growth of the projected transverse beam emittances due to correlations between the transverse and longitudinal degrees of freedom that are introduced within the gun and downstream rf cavities. A strategy is described to mitigate this emittance growth by allowing the beam to propagate along a carefully tuned off-axis trajectory in downstream rf cavities to remove the time-dependent rf kicks introduced in the gun. Along this trajectory, short range wakefields do not degrade the emittance, and long range wakefields degrade the emittance for very high repetition rate only.

  5. Experimental Study of Diamond Like Carbon (DLC) Coated Electrodes for Pulsed High Gradient Electron Gun

    CERN Document Server

    Paraliev, M; Ivkovic, S; Le Pimpec, F

    2010-01-01

    For the SwissFEL Free Electron Laser project at the Paul Scherrer Institute, a pulsed High Gradient (HG) electron gun was used to study low emittance electron sources. Different metals and surface treatments for the cathode and anode were studied for their HG suitability. Diamond Like Carbon (DLC) coatings are found to perform exceptionally well for vacuum gap insulation. A set of DLC coated electrodes with different coating parameters were tested for both vacuum breakdown and photo electron emission. Surface electric fields over 250MV/m (350 - 400kV, pulsed) were achieved without breakdown. From the same surface, it was possible to photo-emit an electron beam at gradients up to 150MV/m. The test setup and the experimental results are presented

  6. Design of a pulsed angular selective electron gun for the KATRIN main spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Winzen, Daniel; Hannen, Volker; Ortjohann, Hans-Werner; Zacher, Michael; Weinheimer, Christian [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet, Muenster (Germany); Collaboration: KATRIN-Collaboration

    2012-07-01

    The KATRIN (KArlsruhe TRItium Neutrino mass) experiment will study the tritium {beta}-spectrum near the endpoint of 18.6 keV, aiming to measure the mass of the electron antineutrino. Using an electrostatic retarding spectrometer (MAC-E-Filter), the projected sensitivity for m{sub ve} is 200 meV/c{sup 2} at 90% C.L. In order to map out the electric and magnetic fields in the main spectrometer, an angular selective electron gun is currently being developed. The e-gun uses an UV-Laser to produce electrons via the photo-electric effect from a copper substrate which are then accelerated electrostatically. It features a small energy spread of approx. 0.1 eV, a sharp emission angle and will be able to cover the whole magnetic flux tube of KATRIN. Using a pulsed laser it is also possible to investigate the time of flight (TOF) of electrons through the spectrometer, offering enhanced sensitivity to spectrometer properties far away from the analysing plane. By comparing information from transmission function measurements and TOF data with Monte Carlo simulations of the setup, one will be able to achieve a detailed understanding of the spectrometer properties.

  7. Electron beam simulation from gun to collector: Towards a complete solution

    Energy Technology Data Exchange (ETDEWEB)

    Mertzig, R., E-mail: robert.mertzig@cern.ch; Shornikov, A., E-mail: robert.mertzig@cern.ch; Wenander, F. [CERN, Geneva 23, CH-1211 (Switzerland); Beebe, E.; Pikin, A. [Brookhaven National Lab, Upton, NY 11973 (United States)

    2015-01-09

    An electron-beam simulation technique for high-resolution complete EBIS/T modelling is presented. The technique was benchmarked on the high compression HEC{sup 2} test-stand with an electron beam current, current density and energy of 10 A, 10 kA/cm{sup 2} and 49.2 keV, and on the immersed electron beam at REXEBIS for electron beam characteristics of 0.4 A, 200 A/cm{sup 2} and 4.5 keV. In both Brillouin-like and immersed beams the electron-beam radius varies from several millimeters at the gun, through some hundreds of micrometers in the ionization region to a few centimeters at the collector over a total length of several meters. We report on our approach for finding optimal meshing parameters, based on the local beam properties such as magnetic field-strength, electron energy and beam radius. This approach combined with dividing the problem domain into sub-domains, and subsequent splicing of the local solutions allowed us to simulate the beam propagation in EBISes from the gun to the collector using a conventional PC in about 24–36 h. Brillouin-like electron beams propagated through the complete EBIS were used to analyze the beam behavior within the collector region. We checked whether elastically reflected paraxial electrons from a Brillouin-like beam will escape from the collector region and add to the loss current. We have also studied the power deposition profiles as function of applied potentials using two electrode geometries for a Brillouin-like beam including the effects of backscattered electrons.

  8. Adaptive electron beam shaping using a photoemission gun and spatial light modulator

    Science.gov (United States)

    Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; Kiefer, Jacob; Bazarov, Ivan

    2015-02-01

    The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

  9. Effect of RF Gradient upon the Performance of the Wisconsin SRF Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, Robert [SRC U. Wisconsin-Madison; Legg, Robert A. [JLAB

    2013-12-01

    The performance of the Wisconsin 200-MHz SRF electron gun is simulated for several values of the RF gradient. Bunches with charge of 200 pC are modeled for the case where emittance compensation is completed during post-acceleration to 85 MeV in a TESLA module. We first perform simulations in which the initial bunch radius is optimal for the design gradient of 41 MV/m. We then optimize the radius as a function of RF gradient to improve the performance for low gradients.

  10. The Use of a Solid State Analog Television Transmitter as a Superconducting Electron Gun Power Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Kulpin, K.J. Kleman, R.A. Legg

    2012-07-01

    A solid state analog television transmitter designed for 200 MHz operation is being commissioned as a radio frequency power amplifier on the Wisconsin superconducting electron gun cavity. The amplifier consists of three separate radio frequency power combiner cabinets and one monitor and control cabinet. The transmitter employs rugged field effect transistors built into one kilowatt drawers that are individually hot swappable at maximum continuous power output. The total combined power of the transmitter system is 33 kW at 200 MHz, output through a standard coaxial transmission line. A low level radio frequency system is employed to digitally synthesize the 200 MHz signal and precisely control amplitude and phase.

  11. Experimental investigation of a 1 kA/cm² sheet beam plasma cathode electron gun.

    Science.gov (United States)

    Kumar, Niraj; Pal, Udit Narayan; Pal, Dharmendra Kumar; Prajesh, Rahul; Prakash, Ram

    2015-01-01

    In this paper, a cold cathode based sheet-beam plasma cathode electron gun is reported with achieved sheet-beam current density ∼1 kA/cm(2) from pseudospark based argon plasma for pulse length of ∼200 ns in a single shot experiment. For the qualitative assessment of the sheet-beam, an arrangement of three isolated metallic-sheets is proposed. The actual shape and size of the sheet-electron-beam are obtained through a non-conventional method by proposing a dielectric charging technique and scanning electron microscope based imaging. As distinct from the earlier developed sheet beam sources, the generated sheet-beam has been propagated more than 190 mm distance in a drift space region maintaining sheet structure without assistance of any external magnetic field.

  12. A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers.

    Science.gov (United States)

    Barcellan, L; Berto, E; Carugno, G; Galet, G; Galeazzi, G; Borghesani, A F

    2011-09-01

    We report on the design of a new type of hot-filament electron gun delivering fairly high current (a few hundreds of μ A) at high voltage (up to 100 kV) in continuous or pulsed mode. Its novel features are that the filament is heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply in order to get rid of bulky isolation transformers, and that the filament current and, hence, the electron gun current, is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. This electron gun is intended for general purposes, although we have especially developed it to meet the needs of our experiment on the infrared emission spectroscopy of rare gas excimers. Our experiment requires that the charge injection into the sample is pulsed and constant and stable in time. The new electron gun can deliver several tens of nC per pulse of electrons of energy up to 100 keV into the sample cell. The new design also eliminates ripples in the emission current and ensures up to 12 h of stable performance. © 2011 American Institute of Physics

  13. A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers

    Energy Technology Data Exchange (ETDEWEB)

    Barcellan, L.; Carugno, G. [INFN Section, Padua (Italy); Berto, E.; Galet, G.; Galeazzi, G. [Department of Physics, University of Padua (Italy); Borghesani, A. F. [INFN Section, Padua (Italy); CNISM Unit, Department of Physics, University of Padua (Italy)

    2011-09-15

    We report on the design of a new type of hot-filament electron gun delivering fairly high current (a few hundreds of {mu} A) at high voltage (up to 100 kV) in continuous or pulsed mode. Its novel features are that the filament is heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply in order to get rid of bulky isolation transformers, and that the filament current and, hence, the electron gun current, is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. This electron gun is intended for general purposes, although we have especially developed it to meet the needs of our experiment on the infrared emission spectroscopy of rare gas excimers. Our experiment requires that the charge injection into the sample is pulsed and constant and stable in time. The new electron gun can deliver several tens of nC per pulse of electrons of energy up to 100 keV into the sample cell. The new design also eliminates ripples in the emission current and ensures up to 12 h of stable performance.

  14. Multiobjective optimizations of a novel cryocooled dc gun based ultrafast electron diffraction beam line

    Science.gov (United States)

    Gulliford, Colwyn; Bartnik, Adam; Bazarov, Ivan

    2016-09-01

    We present the results of multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at the sample location have been performed for three different sample radii: 50, 100, and 200 μ m , for two final bunch charges: 1 05 electrons (16 fC) and 1 06 electrons (160 fC). Example optimal solutions are analyzed, and the effects of disordered induced heating estimated. In particular, a relative coherence length of Lc ,x/σx=0.27 nm /μ m was obtained for a final bunch charge of 1 05 electrons and final bunch length of σt≈100 fs . For a final charge of 1 06 electrons the cryogun produces Lc ,x/σx≈0.1 nm /μ m for σt≈100 - 200 fs and σx≥50 μ m . These results demonstrate the viability of using genetic algorithms in the design and operation of ultrafast electron diffraction beam lines.

  15. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

    Science.gov (United States)

    Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  16. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source.

    Science.gov (United States)

    Wells, R P; Ghiorso, W; Staples, J; Huang, T M; Sannibale, F; Kramasz, T D

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  17. Simulation of the Beam Dump for a High Intensity Electron Gun

    CERN Document Server

    Doebert, S; Lefevre, T; Pepitone, K

    2014-01-01

    The CLIC Drive Beam is a high-intensity pulsed electron beam. A test facility for the Drive Beam electron gun will soon be commissioned at CERN. In this contribution we outline the design of a beam dump / Faraday cup capable of resisting the beam’s thermal load. The test facility will operate initially up to 140 keV. At such low energies, the electrons are absorbed very close to the surface of the dump, leading to a large energy deposition density in this thin layer. In order not to damage the dump, the beam must be spread over a large surface. For this reason, a small-angled cone has been chosen. Simulations using Geant4 have been performed to estimate the distribution of energy deposition in the dump. The heat transport both within the electron pulse and between pulses has been modelled using finite element methods to check the resistance of the dump at high repetition rates. In addition, the possibility of using a moveable dump to measure the beam profile and emittance is discussed.

  18. A multiple gap plasma cathode electron gun and its electron beam analysis in self and trigger breakdown modes

    Science.gov (United States)

    Kumar, Niraj; Pal, Dharmendra Kumar; Jadon, Arvind Singh; Pal, Udit Narayan; Rahaman, Hasibur; Prakash, Ram

    2016-03-01

    In the present paper, a pseudospark discharge based multiple gap plasma cathode electron gun is reported which has been operated separately in self and trigger breakdown modes using two different gases, namely, argon and hydrogen. The beam current and beam energy have been analyzed using a concentric ring diagnostic arrangement. Two distinct electron beams are clearly seen with hollow cathode and conductive phases. The hollow cathode phase has been observed for ˜50 ns where the obtained electron beam is having low beam current density and high energy. While in conductive phase it is high current density and low energy electron beam. It is inferred that in the hollow cathode phase the beam energy is more for the self breakdown case whereas the current density is more for the trigger breakdown case. The tailor made operation of the hollow cathode phase electron beam can play an important role in microwave generation. Up to 30% variation in the electron beam energy has been achieved keeping the same gas and by varying the breakdown mode operations. Also, up to 32% variation in the beam current density has been achieved for the trigger breakdown mode at optimized trigger position by varying the gas type.

  19. Diagnostic for a high-repetition rate electron photo-gun and first measurements

    Science.gov (United States)

    Filippetto, D.; Doolittle, L.; Huang, G.; Norum, E.; Portmann, G.; Qian, H.; Sannibale, F.

    2015-05-01

    The APEX electron source at LBNL combines the high-repetition-rate with the high beam brightness typical of photoguns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment, opening the doors of the high average power to brightness-hungry applications as X-Ray FELs, MHz ultrafast electron diffraction etc.. As first step, a complete characterization of the beam parameters is foreseen at the Gun beam energy of 750 keV. Diagnostics for low and high current measurements have been installed and tested, and measurements of cathode lifetime and thermal emittance in a RF environment with mA current performed. The recent installation of a double slit system, a deflecting cavity and a high precision spectrometer, allow the exploration of the full 6D phase space. Here we discuss the present layout of the machine and future upgrades, showing the latest results at low and high repetition rate, together with the tools and techniques used.

  20. Multi-objective Optimizations of a Normal Conducting RF Gun Based Ultra Fast Electron Diffraction Beamline

    CERN Document Server

    Gulliford, C; Maxson, J; Bazarov, I

    2016-01-01

    We present the results of multi-objective genetic algorithm optimizations of a potential single shot ultra fast electron diffraction beamline utilizing a 100 MV/m 1.6 cell normal conducting rf (NCRF) gun, as well as a 9 cell 2pi/3 bunching cavity placed between two solenoids. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at the sample location have been performed for a charge of 1e6 electrons. Analysis of the solutions is discussed, as are the effects of disorder induced heating. In particular, for a charge of $10^6$ electrons and final beam size greater than or equal to 25 microns, we found a relative coherence length of 0.07, 0.1, and 0.2 nm/micron for a final bunch length of approximately 5, 30, and 100 fs, respectively. These results demonstrate the viability of using geneti...

  1. 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…

  2. Pierce Lumber, Inc.

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Pierce Lumber, Inc. (“Respondent”), located at 1629 13th Street, Belle Plaine, IA for alleged violations of its National Pollutant Discharge Elimination System permit (perm

  3. A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers

    CERN Document Server

    Barcellan, L; Carugno, G; Galet, G; Galeazzi, G; Borghesani, A F

    2011-01-01

    We report on the design of a new type of electron gun to be used for experiments of infrared emission spectroscopy of rare gas excimers. It is based on a filament heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply. The filament current is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. Our experiment requires that the charge injection is pulsed and constant and stable in time. This electron gun can deliver several tens of nC per pulse of electrons of energy up to $100\\,$keV into the sample cell. This new design eliminates ripples in the emission current and ensures up to 12 hrs of stable performance.

  4. Tatuajes y "piercing" Tattoos and piercing

    Directory of Open Access Journals (Sweden)

    L E Valle

    2006-03-01

    Full Text Available A pesar de estar en el siglo XXI se ha retomado el lenguaje con códigos de comunicación arcaicos. Los jóvenes forman su identidad mediante la interacción con sus pares y los tatuajes y "piercing" tienen sus propios códigos, que son interpretados por el grupo que los lleva. Actualmente los tatuajes y los "piercing" encuentran su lugar predominante en la población adolescente, donde se han reinstalado por ser "moda" y generalmente se aceptan por estar generalizados. Asimismo los observamos en poblaciones marginales: de drogadictos y carcelarias. Realizarse un tatuaje y/o "piercing" implica ciertos riesgos, entre los que podemos mencionar la transmisión de infecciones que pueden ser localizadas en las zonas del tatuaje y/o "piercing"; y/o generalizadas como las virósicas algunas de las cuales conllevan riesgos de salud como el virus del HIV, de las hepatitis A,B,C. Pueden observarse también reacciones alérgicas, de hipersensibilidad, liquenoides, granulomatosas y varias como cicatrices hipertróficas y queloides; asimismo desencadenar un primer episodio de psoriasis, lupus, etc. Dentro de las recomendaciones para informar a la población deberíamos incluir: que las regiones del cuerpo más riesgosas para la realización de los mismos (que debieran evitarse son aquellas que asientan en cabeza (incluyendo boca, nariz, cuello y órganos genitales. También es importante tener la vacunación antitetánica actualizada, considerar las condiciones de higiene del local donde se va a asistir y el tipo de material a utilizar, debiendo ser en lo posible material descartable. Los cuidados durante los primeros días post práctica son: mantener la zona limpia y seca, baños cortos, secarse sin frotado y no exponerse al sol por tres o cuatro meses. Asimismo es aconsejable ante cualquier reacción concurrir a la consulta profesional.In spite of being in the XXI century, several archaic codes of communication language have been restablished. Young

  5. Intial characterization fo a commerical electron gun for profiling high intensity proton beams in Project X

    Energy Technology Data Exchange (ETDEWEB)

    Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.; Thangaraj, J.C.T.; Zhang, D.; /Fermilab; Blokland, W.; /Oak Ridge

    2011-03-01

    Measuring the profile of a high-intensity proton beam is problematic in that traditional invasive techniques such as flying wires don't survive the encounter with the beam. One alternative is the use of an electron beam as a probe of the charge distribution in the proton beam as was done at the Spallation Neutron Source at ORNL. Here we present an initial characterization of the beam from a commercial electron gun from Kimball Physics, intended for use in the Fermilab Main Injector for Project X. Despite the fact that the horizontal spot size is abnormally large in the high current measurement, the spot size at the downstream cross X2 is reasonable in the context of measuring the deflection. A thin foil OTR would help with the beam heating and should be tried. The next phase of this experiment is to simulate the proton beam with a pair of current carrying wires and to design and construct a fast deflector. Some of the remaining issues to be considered include determining the minimum beam current needed to observe the deflected beam for a given sweep time and the impact of longitudinal variations in the charge density of the bunch.

  6. Development of an ultrafast electron source based on a cold-field emission gun for ultrafast coherent TEM

    Science.gov (United States)

    Caruso, Giuseppe Mario; Houdellier, Florent; Abeilhou, Pierre; Arbouet, Arnaud

    2017-07-01

    We report on the design of a femtosecond laser-driven electron source for ultrafast coherent transmission electron microscopy. The proposed architecture allows introducing an ultrafast laser beam inside the cold field emission source of a commercial TEM, aligning and focusing the laser spot on the apex of the nanoemitter. The modifications of the gun assembly do not deteriorate the performances of the electron source in conventional DC mode and allow easy switching between the conventional and ultrafast laser-driven emission modes. We describe here this ultrafast electron source and discuss its properties.

  7. Multiobjective optimization design of an rf gun based electron diffraction beam line

    Science.gov (United States)

    Gulliford, Colwyn; Bartnik, Adam; Bazarov, Ivan; Maxson, Jared

    2017-03-01

    Multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line comprised of a 100 MV /m 1.6-cell normal conducting rf (NCRF) gun, as well as a nine-cell 2 π /3 bunching cavity placed between two solenoids, have been performed. These include optimization of the normalized transverse emittance as a function of bunch charge, as well as optimization of the transverse coherence length as a function of the rms bunch length of the beam at the sample location for a fixed charge of 1 06 electrons. Analysis of the resulting solutions is discussed in terms of the relevant scaling laws, and a detailed description of one of the resulting solutions from the coherence length optimizations is given. For a charge of 1 06 electrons and final beam sizes of σx≥25 μ m and σt≈5 fs , we found a relative coherence length of Lc ,x/σx≈0.07 using direct optimization of the coherence length. Additionally, based on optimizations of the emittance as a function of final bunch length, we estimate the relative coherence length for bunch lengths of 30 and 100 fs to be roughly 0.1 and 0.2 nm /μ m , respectively. Finally, using the scaling of the optimal emittance with bunch charge, for a charge of 1 05 electrons, we estimate relative coherence lengths of 0.3, 0.5, and 0.92 nm /μ m for final bunch lengths of 5, 30 and 100 fs, respectively.

  8. Cathode performance during two beam operation of the high current high polarization electron gun for eRHIC

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, O. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ben-Zvi, I. [Brookhaven National Lab. (BNL), Upton, NY (United States); Degen, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Lambiase, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meng, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pikin, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rao, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sheehy, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Skaritka, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pietz, J. [Transfer Engineering and Manufacturing, Inc., Fremont, CA (United States); Ackeret, M. [Transfer Engineering and Manufacturing, Inc., Fremont, CA (United States); Yeckel, C. [Stangenes Industries, Palo Alto, CA (United States); Miller, R. [Stangenes Industries, Palo Alto, CA (United States); Dobrin, E. [Stangenes Industries, Palo Alto, CA (United States); Thompson, K. [Stangenes Industries, Palo Alto, CA (United States)

    2015-05-03

    Two electron beams from two activated bulk GaAs photocathodes were successfully combined during the recent beam test of the High Current High Polarization Electron gun for eRHIC. The beam test took place in Stangenes Industries in Palo Alto, CA, where the cathodes were placed in diagonally opposite locations inside the high voltage shroud. No significant cross talking between the cathodes was found for the pertinent vacuum and low average current operation, which is very promising towards combining multiple beams for higher average current. This paper describes the cathode preparation, transport and cathode performance in the gun for the combining test, including the QE and lifetimes of the photocathodes at various steps of the experiment.

  9. Multi-objective Optimizations of a Novel Cryo-cooled DC Gun Based Ultra Fast Electron Diffraction Beamline

    OpenAIRE

    Gulliford, C.; Bartnik, A.; Bazarov, I.

    2015-01-01

    We present the results of multi-objective genetic algorithm optimizations of a potential single shot ultra fast electron diffraction beamline utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final r...

  10. Survey of SRF guns

    Energy Technology Data Exchange (ETDEWEB)

    Belomestnykh, S.

    2011-07-25

    Developing Superconducting RF (SRF) electron guns is an active field with several laboratories working on different gun designs. While the first guns were based on elliptic cavity geometries, Quarter Wave Resonator (QWR) option is gaining popularity. QWRs are especially well suited for producing beams with high charge per bunch. In this talk we will describe recent progress in developing both types of SRF guns. SRF guns made excellent progress in the last two years. Several guns generated beams and one, at HZDR, injected beam into an accelerator. By accomplishing this, HZDR/ELBE gun demonstrated feasibility of the SRF gun concept with a normal-conducting Cs{sub 2}Te cathode. The cathode demonstrated very good performance with the lifetime of {approx}1 year. However, for high average current/high bunch charge operation CsK{sub 2}Sb is preferred as it needs green lasers, unlike UV laser for the Cs{sub 2}Te, which makes it easier to build laser/optics systems. Other high QE photocathodes are being developed for SRF guns, most notably diamond-amplified photocathode. Several QWR guns are under development with one producing beam already. They are very promising for high bunch charge operation. The field is very active and we should expect more good results soon.

  11. Investigation in morphology and optical properties of electron beam gun evaporated nanostructured Bromoindium phthalocyanine thin films

    Science.gov (United States)

    Azim-Araghi, M. E.; Sahebi, R.

    2014-01-01

    Bromoindium phthalocyanine in thin film form was prepared by electron beam gun evaporation technique, using pre-cleaned polyborosilicate glass as substrate. 2D AFM image confirms that the surface of BrInPc thin film is granular with a grain size of 40-60 nm. 3D AFM image confirms that surface is homogeneous and its RMS roughness is 4.9 nm. The UV-VIS absorption spectrum showed two well-known absorption bands of the phthalocyanines, B and Q bands and characteristics Davydov splitting were observed. The optical transition determined to be direct allowed and the value of optical band gap was obtained. The value of Urbach energy was calculated. To investigation in the effect of thermal annealing on optical properties of BrInPc thin films, we annealed some thin films at 473 and 603 K for 1 h. As the result of thermal annealing we observed another absorption peak, named N-band, in absorption spectrum. A red shift observed in the position of B-band and Q-band peaks. There was not changing in optical transition mechanism. The value of optical band gap decreased and the Urbach energy increased as the result of thermal annealing.

  12. High-current-density gun with a LaB6 cathode

    Science.gov (United States)

    Ebihara, K.; Hiramatsu, S.

    1996-08-01

    To develop a high-current electron gun for an induction linac, a prototype of a Pierce-type electron gun using planar 12-mm-diam lanthanum hexaboride (LaB6) is studied as a thermionic emitter at high current densities. The cathode is heated up to temperatures of 1750 °C by electron bombardment and thermal radiation from a tungsten heater. The heater that has the highest temperature in the gun is thermally isolated from the outer vacuum chamber with heat shields. The bombardment voltage of ˜1 kV is typically applied to a gap between the cathode and the heater. The gun has been operated up to voltages of 55 kV, obtaining a maximum current density of 20 A/cm2 with a pulse width of 250 ns at a cathode temperature of 1600 °C. High-voltage pulsing results show that the gun, with applied voltages of over 40 kV, is operated in space-charge-limited region at temperatures of over 1600 °C; also it is operated in a temperature-limited region at temperatures of less than 1500 °C. An effective work function of 2.68 eV is obtained. The cathode, when heated up to 1600 °C, emits over 7 A of electrons with a ˜20% reduction after 850 h of continuous operation. These measurements were made between vacuum pressures of 10-6 and 10-7 Torr.

  13. High-gradient high-duty-factor Rf photo-cathode electron gun

    Science.gov (United States)

    Rimmer, R. A.; Hartman, N.; Lidia, S. M.; Wang, S.

    2002-05-01

    We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure.

  14. Design cusp electron gun for of 0.6 THz 3rd-harmonic large orbit gyrotron%0.6THz三次谐波大回旋电子枪设计

    Institute of Scientific and Technical Information of China (English)

    马春燕; 胡强; 袁学松; 韩煜; 鄢扬

    2012-01-01

    Large orbit axis-encircling electron beams can provide improved coupling and mode selectivity in a high harmonic terahertz gyrotron. For developing a 0. 6 THz 3rd-harmonic large orbit gyrotron, a cusp gun with a beam voltage of 55 kV and a beam current of 1 A has been designed based on a comparatively simple Pierce-type electron gun and cusp magnetic field. The optimized result shows that the velocity ratio, axial velocity spread and transverse velocity spread are 1. 53, 7. 10% and 3. 39% , respectively.%基于会切磁场的理论模型,采用粒子模拟软件对0.6 THz三次谐波的太赫兹回旋管所需的大回旋电子光学系统进行研究.文中通过大量的模拟计算,分析讨论了不同参数对电子注的横向速度离散、纵向速度离散及横纵速度比的影响,优化了电子光学系统的性能参量,得到符合设计要求且具有工程实际应用的电子枪,该电子枪能够产生55 kV,1A,横向速度离散为3.39%、纵向速度离散为7.10%、横纵速度比为1.53的大回旋电子注.

  15. Modification of anisotropic plasma diffusion via auxiliary electrons emitted by a carbon nanotubes-based electron gun in an electron cyclotron resonance ion source.

    Science.gov (United States)

    Malferrari, L; Odorici, F; Veronese, G P; Rizzoli, R; Mascali, D; Celona, L; Gammino, S; Castro, G; Miracoli, R; Serafino, T

    2012-02-01

    The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed.

  16. Pierce Patriarch "Prince of Quacks"

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This article provides brief biographies for Dr. Valentine Mott Pierce and his father, Dr. Ray Vaughn Pierce. Dr. R.V. Pierce has been described as the “uberquack,”...

  17. TiN coated aluminum electrodes for DC high voltage electron guns

    Energy Technology Data Exchange (ETDEWEB)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A., E-mail: aelmusta@odu.edu [Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529 and The Applied Research Center, Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Taus, Rhys [Department of Physics, Loyola Marymount University, Los Angeles, California 90045 (United States); Forman, Eric; Poelker, Matthew [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2015-05-15

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached −225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ∼22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.

  18. Robe Development for Electrical Conductivity Analysis in an Electron Gun Produced Helium Plasma

    Science.gov (United States)

    Bragg-Sitton, Shannon M.; Bitteker, Leo; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    The use of magnetohydrodynamic (MHD) power conversion systems, potentially coupled with a fission power source, is currently being investigated as a driver for an advanced propulsion system, such as a plasma thruster. The efficiency of a MHD generator is strongly dependent on the electrical conductivity of the fluid that passes through the generator; power density increases as fluid conductivity increases. Although traditional MHD flows depend on thermal ionization to enhance the electrical conductivity, ionization due to nuclear interactions may achieve a comparable or improved conductivity enhancement while avoiding many of the limitations inherent to thermal ionization. Calculations suggest that nuclear-enhanced electrical conductivity increases as the neutron flux increases; conductivity of pure He-3 greater than 10 mho/m may be achievable if exposed to a flux greater than 10(exp 12) neutrons/cm2/s.) However, this remains to be demonstrated experimentally. An experimental facility has been constructed at the Propulsion Research Center at the NASA Marshall Space Flight Center, using helium as the test fluid. High energy electrons will be used to simulate the effects of neutron-induced ionization of helium gas to produce a plasma. These experiments will be focused on diagnosis of the plasma in a virtually static system; results will be applied to future tests with a MHD system. Initial experiments will utilize a 50 keV electron gun that can operate at up to a current of 200 micro A. Spreading the electron beam over a four inch diameter window results in an electron flux of 1.5x 10(exp 13) e/sq cm/s. The equivalent neutron flux that would produce the same ionization fraction in helium is 1x10(exp 12) n/sq cm/s. Experiments will simulate the neutron generated plasma modeled by Bitteker, which takes into account the products of thermal neutron absorption in He-3, and includes various ion species in estimating the conductivity of the resulting plasma. Several

  19. Post-piercing perichondritis.

    Science.gov (United States)

    Fernandez, André de Paula; Castro Neto, Ivan de; Anias, Christiane Ribeiro; Pinto, Patrícia Ciminelli Linhares; Castro, Jair de Carvalho E; Carpes, Arturo Frick

    2008-01-01

    Piercing has become more and more popular among adolescents. The procedure is generally performed by unqualified professionals and carries its risk. Non-sterilized material or inappropiate hygiene increases the possibility of perichondritis and celulitis. The disease is characterized by erythema of the auricula pinna, unbearable pain and fever. Left untreated, the condition progresses with edema along the auricula and abscess formation that may result in ischemic necrosis and a cauliflower anesthetic deformation. The most common bacteria is Pseudomonas aeruginosa. In cases with abscesses, drainage is necessary along with antibiotic therapy guided by cultures and antibiogram. The aim of this case report was to review the past 10 years of published papers dealing with anatomical aspects of the auricular pinna, the history of piercing and its most common complications. A case report of perichondritis after 'high' ear piercing that required surgical treatment and that progressed with no esthetic loss. Theoretical and practical experience based on a review and a report of a case that progressed satisfactorily. The increased incidence of perichondritis in adolescents should require more elaborated primary prevention measures.

  20. 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 ...

  1. 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.

  2. W(310) cold-field emission characteristics reflecting the vacuum states of an extreme high vacuum electron gun

    Science.gov (United States)

    Cho, Boklae; Shigeru, Kokubo; Oshima, Chuhei

    2013-01-01

    An extremely high vacuum cold-field electron emission (CFE) gun operating at pressures ranging from ˜10-8 Pa to ˜10-10 Pa was constructed. Only the CFE current emitting from W(310) surfaces revealed the existence of a "stable region" with high current angular density just after tip flash heating. In the "stable region," the CFE current was damped very slowly. The presence of non-hydrogen gas eliminated this region from the plot. Improvement of the vacuum prolonged the 90% damping time of the CFE current from ˜10 min to 800 min. The current angular density I' of CFE current was 60 and 250 μA/sr in the "stable region" for total CFE currents of 10 and 50 μA, respectively. These results were about three times larger than I' when measured after the complete damping of the CFE current. The CFE gun generated bright scanning transmission electron microscopy images of a carbon nanotube at 30 kV.

  3. Diagrammer hos Pierce og Deleuze

    DEFF Research Database (Denmark)

    Busk, Malene

    2006-01-01

    Artiklen omhandler to forskellige begreber om diagrammet, nemlig Pierces og Deleuzes. De definerer udfra to meget forskellige udgangspukter begge diagrammet som kreativt redskab......Artiklen omhandler to forskellige begreber om diagrammet, nemlig Pierces og Deleuzes. De definerer udfra to meget forskellige udgangspukter begge diagrammet som kreativt redskab...

  4. Electromagnetic Gun

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    In the early 14th century,Europeons used guns in battle for the first time. The secret was gunpowder,a volatile mixture of chemicals that exploded when lit. Since then,all guns have relied on gunpowder or other chemical propellants.

  5. Multi-objective Optimizations of a Novel Cryo-cooled DC Gun Based Ultra Fast Electron Diffraction Beamline

    CERN Document Server

    Gulliford, C; Bazarov, I

    2015-01-01

    We present the results of multi-objective genetic algorithm optimizations of a potential single shot ultra fast electron diffraction beamline utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at sample location have been performed for three different sample radii: 50, 100, 200 microns, for two final bunch charges: 100k and 1000k electrons. Analysis of the solutions is discussed, as are the effects of disorder induced heating. In particular, a coherence length per rms spot size of 0.27 nm/micron was obtained for a final bunch charge of 100k electrons and final rms bunch length of approximately 100 fs. For a final charge of 1000k electrons the cryogun produces a coherence length per rms spot size...

  6. Contact hypersensitivity after tongue piercing

    Directory of Open Access Journals (Sweden)

    Ananta Herachakri P

    2010-09-01

    Full Text Available Background: Recently tongue piercing has become increasingly popular in the society. Several case reports have presented various complications of tongue piercing. However, there is no scientific evidence about contact hypersensitivity to tongue piercing. Purpose: The aim of this study was to investigate the contact hypersensitivity after using tongue piercing. Methods: Nineteen male Rattus norvegicus were divided into three groups: group A treated with vaseline on the back and dorsum tongue (control group, group B (I treated with HgCl2 10% cream on the tongue dorsum, group B (II treated with tongue piercing for 10 days and group C with HgCl 2 10% cream on the back, ear lobe, and tongue, then re-exposure with same materials on ear, back and tongue for 24 and 48 hours. Before and after 24 and 48 hours applications, ear width was measured with sliding caliper. At the end of treatments, the rats were sacrificed. All tissue specimens were made for Hematoylin Eosine (H&E staining examination. The number of mononuclear cells was counted under light microscope Data was analyzed with One-Way ANOVA followed by LSD (p<0.05. Results: The result of this study showed that there were a significant difference of the thickness of ear lobe and the number of mononuclear cells (lymphocyte and monocyte among all groups. Conclusion: It is concluded that tongue piercing induce contact hypersensitivity.Latar belakang: Saat ini pemakaian tongue piercing sangat popular di masyarakat. Beberapa laporan kasus menunjukkan bahwa tongue piercing menimbulkan beberapa komplikasi. Namun, belum ada bukti ilmiah mengenai reaksi hipesensitivitas tongue piercing. Tujuan: Untuk mengetahui reaksi hipersensitivitas setelah menggunakan tongue piercing. Metode: Sembilan belas tikus jantan Rattus novergicus yang dibagi dalam tiga kemlompok yaitu: grup A diberi perlakuan dengan vaselin pada punggung dan dorsum lidah, grup B (I diberi perlakuan dengan krim HgCl2 10% pada dorsum lidah dan B

  7. High ear-piercing: an increasingly popular procedure with serious complications. Is good clinical practice exercised?

    Science.gov (United States)

    Lyons, Marie; Stephens, Joanna; Wasson, Joseph; DeZoysa, Nilantha; Vlastarakos, Petros V

    2012-03-01

    This study aimed to explore the current practice of performing high ear-piercing regarding consent protocols, and methods of practice using questionnaire-based survey in Hertfordshire and North London. Recommendations for good clinical practice are also made. 100 establishments performing ear piercing were identified. A 16-item questionnaire on techniques used, methods of high-ear piercing, methods of sterilization, consent issues and aftercare was completed. Seventy-six establishments agreed to participate. All practitioners prepared the skin before piercing. 58 (76%) used a needle for piercing, 11 (15%) used a spring-loaded gun and seven (9%) used both. 97% of the practitioners obtained written consent before proceeding. 9 (12%) had a lower age limit of 16 years and three (4%) of 18 years. 27 piercers (36%) provided an aftercare leaflet, 41 (54%) warned the patients about risks of infection, 16 (21%) warned about cosmetic deformity and 1 (1%) specifically mentioned cauliflower ear. Results indicated that high ear piercing is an invasive procedure with a significant risk of complications leading to cosmetic deformity. Establishments should be required to counsel patients properly about the risks and potential complications of the procedure. A code of practice should be drawn up with a minimum age for piercing, requirement for proper consent, excellent hygiene and good information for postoperative care.

  8. How Dr. Pierce Promoted Himself

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This article is about Dr. Raymond V Pierce who owned St. Vincent Island before it became a refuge. The doctor painted advertisements for his famous “Woman’s Tonic”...

  9. [Piercing: health education or medicalization?].

    Science.gov (United States)

    Meningaud, J P; Moutel, G; Hervé, C

    2000-06-10

    In Europe, the piercing mode has naturally been associated with specific complications raising an important public health problem. The debate on the role physicians should play requires a careful analysis of the ethical issues involved. Specifically, should the piercing be done in a medical setting? This question is raised because, when performed under ideal conditions, the act of piercing requires a certain degree of medical competency: history taking, asepsia, technical procedure (hemostasis), anesthesia.... However, mandatory medicalization would not, in our opinion, appear to be desirable since we are dealing with a social rite which lies outside the domain of specific medical care. Nevertheless, although we do not advocate systematic medicalization, we do believe that medicine should play a role, in terms of public health, in this emerging practice. We discuss the modalities of a health education dialogue which could be established with professional practicing piercing.

  10. The Electron Gun's Design with High Performance for Ka-Band TWT%Ka波段行波管高性能电子枪设计

    Institute of Scientific and Technical Information of China (English)

    赵国庆; 王文祥; 宫玉彬; 魏彦玉; 黄民智

    2012-01-01

    The initial structure parameters of the electron gun for Ka-band TWT can be obtained by the synthesis iteration proposed by Vaughan, and then, the modifications for electron gun's structure are performed by stimulation and optimization with the TAU. With comparison of the uniformity electron's emission density of the cathode surface, the influence of trajectories for different thermal emission angles of e-lectrons, the trajectory's laminar and the radial current density distribution near the electron beam's waist, the final structure of the electron gun is got. The test result is in agreement with the optimized design for Ka-band TWT electron gun.%利用学者Vaughan等提出的皮尔斯电子枪设计综合迭代法计算得到某Ka波段行波管电子枪的基本结构参数;在此基础上,采用电子光学数值模拟软件Tau进行模拟优化进一步修改电子枪各结构尺寸;在模拟优化过程中,通过量化比较、判断阴极表面电子发射密度的均匀性,比较阴极表面部分热初速电子非垂直发射时对电子注轨迹的影响程度,比较注腰位置附近电子注层流性及径向密度分布均匀性等,最后得到优化的电子枪结构设计.对装配有此优化设计电子枪的行波管进行了实验研究,测试结果达到设计要求.

  11. THz and Sub-THz Capabilities of a Table-Top Radiation Source Driven by an RF Thermionic Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, Alexei V.; Agustsson, R.; Boucher, S.; Campese, Tara; Chen, Y.C.; Hartzell, Josiah J.; Jocobson, B.T.; Murokh, A.; O' Shea, F.H.; Spranza, E.; Berg, W.; Borland, M.; Dooling, J. C.; Erwin, L.; Lindberg, R. R.; Pasky, S.J.; Sereno, N.; Sun, Y.; Zholents, A.

    2017-06-01

    Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes including conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources.

  12. In Vitro Study on the Adhesion and Colonization of Candida Albicans on Metal and Acrylic Piercings

    Directory of Open Access Journals (Sweden)

    Stamenov N.

    2016-03-01

    Full Text Available Oral/perioral piercing may provide an ideal environment for adhesion and colonization of microorganisms. The aim of this study is to perform an “in vitro” research on the capabilities of adhesion of Candida albicans on oral piercings made of plastic and metal. Acrylic and metal piercings were incubated with Candida albicans and then were observed using scanning electron microscopy under different magnifications. A lot of irregularities and roughness were observed on the surface of the plastic piercing unlike the surface of the metal one, which is not so rough. Nevertheless, the number of Candida albicans colonies was considerably larger on the scanned metal surface in comparison to the plastic surface. In vitro the metal surface of the piercing creates better environment for the adhesion and colonization of microorganisms than the acrylic. This could be attributed to the electrostatic forces that most likely attract Candida albicans to the metal piercing in the early stages of biofilm formation.

  13. Stimulation of plasma waves by electron guns on the ISEE-1 satellite

    Science.gov (United States)

    Lebreton, J.-P.; Torbert, R.; Anderson, R.; Harvey, C.

    1982-01-01

    The results of the ISEE-1 satellite experiment relating to observations of the waves stimulated during electron injections, when the spacecraft is passing through the magnetosphere, the magnetosheath, and the solar wind, are discussed. It is shown that the injection of an electron beam current of the order of 10 to 60 microamperes with energies ranging from 0 to 40 eV produces enhancements in the electric wave spectrum. An attempt has been made to identify the low-frequency electrostatic wave observed below the ion plasma frequency as an ion acoustic mode, although the excitation mechanism is not clear. A coupling mechanism between the electron plasma mode and streaming electrons with energies higher than the thermal speed of the cold electron population has been proposed to explain the observations above the electron plasma frequency.

  14. 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)

  15. Improvement of electron beam properties by reducing back-bombardment effects in a thermionic RF gun

    CERN Document Server

    Kii, Toshiteru; Ohgaki, Hideaki; Tometaka, Isao; Yamane, Koshiro; Yamazaki, Tetsuo; Yoshikawa, Kiyoshi

    2003-01-01

    In the Free Electron Laser (FEL) experiment, where a long beam macro- pulse is required, energy shift caused by an increase of current density at the cathode surface due to heating by back-streaming electrons is quite serious. It was numerically found that the low- energy component of the back-streaming electrons causes a serious effect. It was also found that the effect can be decreased by applying a transverse magnetic field by calculating time evolution of the cathode surface temperature with a one-dimensional thermal conduction model.

  16. Transverse Laser Beam Shaping in High Brightness Electron Gun at ATF

    CERN Document Server

    Roychowdhury, S

    2005-01-01

    The brightness of electron beams from a photo injector is influenced by the transverse and longitudinal distribution of the laser beam illuminating the cathode. Previous studies at Brookhaven Accelerator Test Facility have shown that formation of an ideal e-beam with lowest transverse emittance requires uniform circular distribution of the emitted electrons. The use of the uniformly distributed power of the laser beam may not lead to that of the emitted electrons because of the non-uniform quantum efficiency. A proper shaping of the laser beam can compensate for this non-uniformity. In this paper we describe the use of digital light processing (DLP) technique based on digital mirror device (DMD) for spatial modulation of the laser beam, for measurements of the quantum efficiency map, and for creating the desirable e-beam density profiles. A DMD is aμelectronic mechanical system (MEMS) comprising of millions of highly reflectiveμmirrors controlled by underlying electronics. We present exper...

  17. Bunching of an Intense Electron-Beam Extracted from a Triode Gun Modulated at 1 Ghz

    NARCIS (Netherlands)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.

    1991-01-01

    We present measurements of the bunch length and emittance of a high-current electron beam, which is extracted from a triode modulated at 1 GHz and subsequently compressed by means of velocity modulation in a prebuncher cavity. The prebuncher is detuned by about 1 MHz in order to ensure that the tota

  18. Development of an X-ray tube for irradiation experiments using a field emission electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Hidetoshi, E-mail: katou-h@aist.go.jp [Research Institute for Measurement and Analytical Instrumentation (RIMA), National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology - AIST, Tsukuba-Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); O' Rourke, Brian E.; Suzuki, Ryoichi [Research Institute for Measurement and Analytical Instrumentation (RIMA), National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology - AIST, Tsukuba-Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Wang, Jiayu; Ooi, Takashi; Nakajima, Hidetoshi [Pureron Japan Co., Ltd., 1-37 Yoshima Industrial Park, Iwaki, Fukushima, 970-1144 (Japan)

    2016-01-21

    A new X-ray tube using a ring-shaped emitter as a field emission electron source has been developed. By using a ring shaped cathode, X-rays can be extracted along the axial direction through the central hole. This cylindrically symmetrical design allows for the tube to be arranged in the axial direction with the high voltage target at one end and the X-ray beam at the other. The newly developed X-ray tube can operate at a tube voltage of more than 100 kV and at a tube current of more than 4 mA, and can be used for irradiation experiments with an irradiation dose range from mGy up to kGy. The X-ray tube can be used immediately after turning on (i.e. there is no stand-by time). In the experimental model, we demonstrated stable electron emission at a tube voltage of 100 kV and at a tube current of 4 mA during a 560 h continuous test.

  19. 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.

  20. Can an electron gun solve the outstanding problem of magnetosphere-ionosphere connectivity?

    Science.gov (United States)

    Delzanno, Gian Luca; Borovsky, Joseph E.; Thomsen, Michelle F.; Gilchrist, Brian E.; Sanchez, Ennio

    2016-07-01

    Determining the magnetic connectivity between magnetospheric phenomena and ionospheric phenomena is an outstanding problem of magnetospheric and ionospheric physics. Accurately establishing this connectivity could answer a variety of long-standing questions. The most viable option to solve this is by means of a high-power electron beam fired from a magnetospheric spacecraft and spotted at its magnetic footpoint in the ionosphere. This has technical difficulties. Progress has been made on mitigating the major issue of spacecraft charging. The remaining physics issues are identified, together with the need for a synergistic effort in modeling, laboratory experiments, and, ultimately, testing in space. The goal of this commentary is to stimulate awareness and interest on the magnetosphere-ionosphere connectivity problem and possibly accelerate progress toward its solution.

  1. 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.

  2. Ion tracking in photocathode rf guns

    Directory of Open Access Journals (Sweden)

    John W. Lewellen

    2002-02-01

    Full Text Available Projected next-generation linac-based light sources, such as PERL or the TESLA free-electron laser, generally assume, as essential components of their injector complexes, long-pulse photocathode rf electron guns. These guns, due to their design rf pulse durations of many milliseconds to continuous wave, may be more susceptible to ion bombardment damage of their cathodes than conventional rf guns, which typically use rf pulses of microsecond duration. This paper explores this possibility in terms of ion propagation within the gun, and presents a basis for future study of the subject.

  3. Improved DC Gun Insulator

    Energy Technology Data Exchange (ETDEWEB)

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  4. HOM damping properties of fundamental power couplers in the superconducting electron gun of the energy recovery LINAC at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hammons, L.; Hahn, H.

    2011-03-28

    Among the accelerator projects under construction at the Relativistic Heavy Ion Collider (RHIC) is an R and D energy recovery LINAC (ERL) test facility. The ERL includes both a five-cell superconducting cavity as well as a superconducting, photoinjector electron gun. Because of the high-charge and high-current demands, effective higher-order mode (HOM) damping is essential, and several strategies are being pursued. Among these is the use of the fundamental power couplers as a means for damping some HOMs. Simulation studies have shown that the power couplers can play a substantial role in damping certain HOMs, and this presentation discusses these studies along with measurements.

  5. Gun Safety (For Parents)

    Science.gov (United States)

    ... Teaching Kids to Be Smart About Social Media Gun Safety KidsHealth > For Parents > Gun Safety Print A ... unloaded, and the ammunition should be stored separately. Guns and Pretend Play Allowing kids to play with ...

  6. Electron Gun Technology

    Science.gov (United States)

    1976-08-01

    charged to 2 kV was switched across the thin-wire discharge (all three wires together, in parallel) by meaus of a thyratron . In this case no...emission coefficient of 10 and the model presented in Se’ on II for the thin-wire discharge, this ratio would be «11. Because of the speculative...nature of botn the model and the assumed value for the secondary emission, such a difference in the two values is not sur- prising. The

  7. Development, construction and characterization of a variable repetitive spin-polarized electron gun with an inverted-geometry insulator; Entwicklung, Aufbau und Charakterisierung einer variabel repetierenden, spinpolarisierten Elektronenkanone mit invertierter Isolatorgeometrie

    Energy Technology Data Exchange (ETDEWEB)

    Espig, Martin

    2016-02-15

    Within the scope of this thesis a pulsed source of spin polarized electrons Photo-CATCH was designed, constructed, characterized and has been put into operation. This source is based on the photoemission of spin-polarized electrons from GaAs-photocathodes. Both the design of the electron gun, consisting of an ultra-high vacuum chamber and an electrode with Pierce geometry, as well as the properties of the electron beam have been simulated with CST Studio. Results were a maximum electric field of (0.064±0.001) MV/m/kV on the electrode surface and a beam emittance as a function of the radius of the laser spot on the photocathode of element of {sub n,x}=(1.7478(4).10{sup -4}.(r)/(μm)+2.8(18).10{sup -5}) mm mrad at a beam current of 100 μA. Currently Photo-CATCH provides electron beams with an energy of 60 keV, which can be expanded up to 100 keV by upgrading the high-voltage power supply. The electron gun has an inverted-geometry insulator to ensure a compact design of the ultra-high vacuum chamber and a maximum person- and machine-safety from sparkovers. Since the properties of the laser light directly affect the properties of the generated electron beam a pulsed semiconductor laser system has been specially developed and built for Photo-CATCH. This is characterized by a high variability of its operating parameters, in particular its wavelength and repetition rate, in order to fulfill the broad variety of requirements of various nuclear physics experiments. By selecting the wavelength of the used laser diode highly polarized or high-current electron beams can be generated from GaAs-photocathodes. The time profile of the laser has direct influence to the longitudinal profile of the electron bunch. Through the radiofrequency modulation of the pumping current of the impedance-matched semiconductor laser system, consisting of a DC power source and an electrical pulse generator with 881 ps broad pump pulses, Lorentz shaped laser pulses with a minimum FWHM of (43.8±1

  8. Pericondrite pós-piercing Post-piercing perichondritis

    Directory of Open Access Journals (Sweden)

    André de Paula Fernandez

    2008-12-01

    Full Text Available O uso de piercing tem se tornado uma prática muito freqüente entre os jovens. O procedimento na maioria vezes realizado por profissionais não-qualificados não é isento de riscos. O manuseio de material contaminado ou a higiene imprópria predispõem à pericondrite e à celulite. A pericondrite caracteriza-se pelo eritema do pavilhão auricular, dor intensa e febre. Sem tratamento, desenvolve-se um edema generalizado do pavilhão com formação de abscesso subpericondrial, podendo evoluir para necrose isquêmica da cartilagem e a temível deformidade estética conhecida como "orelha em couve flor". O agente responsável mais encontrado é o Pseudomonas aeruginosa. No estágio inicial da doença o tratamento pode ser feito com antibióticos de amplo espectro. Nos casos em que o abscesso está presente, a incisão e drenagem cirúrgica são obrigatórios acompanhado de antibioticoterapia guiado pela cultura e antibiograma. OBJETIVO: O objetivo deste relato de caso é realizar uma revisão bibliográfica dos últimos 10 anos abordando os aspectos anatômicos do pavilhão auricular, a história do uso de piercing e suas mais conhecidas complicações. MÉTODO: Relato de um caso de pericondrite pós-piercing transcartilaginoso onde houve a necessidade de tratamento cirúrgico com praticamente nenhuma deformidade estética. RESULTADO: Aquisição de experiência teórico-prática através de revisão bibliográfica e relato de um caso de evolução favorável para a paciente. CONCLUSÃO: Incidência crescente das complicações de pericondrites na população jovem deve levar à prevenção primária mais elaborada.Piercing has become more and more popular among adolescents. The procedure is generally performed by unqualified professionals and carries its risk. Non-sterilized material or inappropiate hygiene increases the possibility of perichondritis and celulitis. The disease is characterized by erythema of the auricula pinna, unbearable pain

  9. 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…

  10. 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/

  11. 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.

  12. 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)

  13. Measurement of groove features and dimensions of the vertical test cathode and the choke joint of the superconducting electron gun cavity of the Energy Recovery LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Hammons, L.; Ke, M.

    2011-10-13

    A testing program for the superconducting electron gun cavity that has been designed for the Energy Recovery LINAC is being planned. The goal of the testing program is to characterize the RF properties of the gun cavity at superconducting temperatures and, in particular, to study multipacting that is suspected to be occurring in the choke joint of the cavity where the vertical test cathode is inserted. The testing program will seek to understand the nature and cause of this multipacting and attempt to eliminate it, if possible, by supplying sufficient voltage to the cavity. These efforts are motivated by the multipacting issues that have been observed in the processing of the fine-grain niobium gun cavity. This cavity, which is being processed at Thomas Jefferson National Laboratory for Brookhaven, has encountered multipacting at a gradient of approximately 3 MV/m and, to date, has resisted efforts at elimination. Because of this problem, a testing program is being established here in C-AD that will use the large-grain niobium gun cavity that currently resides at Brookhaven and has been used for room-temperature measurements. The large-grain and fine-cavities are identical in every aspect of construction and only differ in niobium grain size. Thus, it is believed that testing and conditioning of the large-grain cavity should yield important insights about the fine-grain cavity. One element of this testing program involves characterizing the physical features of the choke joint of the cavity where the multipacting is believed to be occurring and, in particular the grooves of the joint. The configuration of the cavity and the vertical test cathode is shown in Figure 1. In addition, it is important to characterize the groove of the vertical test cathode. The grooved nature of these two components was specifically designed to prevent multipacting. However, it is suspected that, because of the chemical processing that the fine-grain gun cavity underwent along with the

  14. 对具有电子枪装置的试验方法和特殊要求%Test Methods and Special Requirements for Devices with Electron Gun

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Background As two tasks of project "Development of International Standards for Chinese advantage Technologies",a National Science and Technology Major Project during China's 11th Five-Year Plan Period,two international standards IEC 60703:2008 Test Methods of Electric Heating Devices with Electron Gun and IEC 60519-7:2008 Safety of Electric Heating Devices Part: 7 Special Requirements for Electric Heating Devices with Electron Gun are based on Chinese advantage technologies,highly recognized by IEC/TC27 for its technological and conceptual innovations in the high-quality,high-level and high-efficiency way.

  15. Piercings en cabeza y cuello

    OpenAIRE

    2014-01-01

    Los piercings corporales son una práctica habitual en la sociedad actual, y consisten en la perforación de un tejido para insertar un aro u otro elemento ornamental. Este procedimiento implica la creación de una puerta de entrada cutánea o mucosa que puede permitir el ingreso de microorganismos, además de la posible formación de cicatrices anómalas. Asimismo, el aro puede predisponer a otras complicaciones como reacciones de hipersensibilidad, desplazamientos o aspiración. Debido a esta ampli...

  16. Ballistic evaluationof LOVA propellant in high calibre gun

    OpenAIRE

    A.G.S. Pillai; R. R. Sanghavi; C. R. Dayanandan; M. M. Joshi; J. S. Karir

    2001-01-01

    'This paper presents the data obrained on dynamic firing of a cellulose acetate binder-based low vulnerability ammunition (LOV A) propellant using 120 mm fin-stabilised armour piercing discarding sabot (FSAPDS) kinetic energyammunition. An optimised propellant composition formulated ~sing fine RDX as an energetic ingredient and a mixture of cellulose acetate and nitrocellulose as binder was qualified fit for firing in a high calibre gun by its successful static evaluation for absolute...

  17. 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.

  18. ANALYTICAL MODELING OF ELECTRON BACK-BOMBARDMENT INDUCED CURRENT INCREASE IN UN-GATED THERMIONIC CATHODE RF GUNS

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, J. P. [Fermilab; Sun, Y. [Argonne; Harris, J. R. [AFRL, NM; Lewellen, J. W. [Los Alamos Natl. Lab.

    2016-09-28

    In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, fieldenhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

  19. The Gun Violence Database

    OpenAIRE

    Pavlick, Ellie; Callison-Burch, Chris

    2016-01-01

    We describe the Gun Violence Database (GVDB), a large and growing database of gun violence incidents in the United States. The GVDB is built from the detailed information found in local news reports about gun violence, and is constructed via a large-scale crowdsourced annotation effort through our web site, http://gun-violence.org/. We argue that centralized and publicly available data about gun violence can facilitate scientific, fact-based discussion about a topic that is often dominated by...

  20. Measurements of line-averaged electron density of pulsed plasmas using a He-Ne laser interferometer in a magnetized coaxial plasma gun device

    Science.gov (United States)

    Iwamoto, D.; Sakuma, I.; Kitagawa, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2012-10-01

    In next step of fusion devices such as ITER, lifetime of plasma-facing materials (PFMs) is strongly affected by transient heat and particle loads during type I edge localized modes (ELMs) and disruption. To clarify damage characteristics of the PFMs, transient heat and particle loads have been simulated by using a plasma gun device. We have performed simulation experiments by using a magnetized coaxial plasma gun (MCPG) device at University of Hyogo. The line-averaged electron density measured by a He-Ne interferometer is 2x10^21 m-3 in a drift tube. The plasma velocity measured by a time of flight technique and ion Doppler spectrometer was 70 km/s, corresponding to the ion energy of 100 eV for helium. Thus, the ion flux density is 1.4x10^26 m-2s-1. On the other hand, the MCPG is connected to a target chamber for material irradiation experiments. It is important to measure plasma parameters in front of target materials in the target chamber. In particular, a vapor cloud layer in front of the target material produced by the pulsed plasma irradiation has to be characterized in order to understand surface damage of PFMs under ELM-like plasma bombardment. In the conference, preliminary results of application of the He-Ne laser interferometer for the above experiment will be shown.

  1. ATA injector-gun calculations

    Energy Technology Data Exchange (ETDEWEB)

    Paul, A.C.

    1981-08-03

    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.

  2. Development of a Robust, High Current, Low Power Field Emission Electron Gun for a Spaceflight Reflectron Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Southard, Adrian E.; Getty, Stephanie A.; Feng, Steven; Glavin, Daniel P.; Auciello, Orlando; Sumant, Anirudha

    2012-01-01

    Carbon materials, including carbon nanotubes (CNTs) and nitrogen-incorporated ultrananocrystalline diamond (N-UNCD), have been of considerable interest for field emission applications for over a decade. In particular, robust field emission materials are compelling for space applications due to the low power consumption and potential for miniaturization. A reflectron time-of-flight mass spectrometer (TOF-MS) under development for in situ measurements on the Moon and other Solar System bodies uses a field emitter to generate ions from gaseous samples, using electron ionization. For these unusual environments, robustness, reliability, and long life are of paramount importance, and to this end, we have explored the field emission properties and lifetime of carbon nanotubes and nitrogen-incorporated ultrananocrystalline diamond (N-UNCD) thin films, the latter developed and patented by Argonne National Laboratory. We will present recent investigations of N-UNCD as a robust field emitter, revealing that this material offers stable performance in high vacuum for up to 1000 hours with threshold voltage for emission of about 3-4 V/lJm and current densities in the range of tens of microA. Optimizing the mass resolution and sensitivity of such a mass spectrometer has also been enabled by a parallel effort to scale up a CNT emitter to an array measuring 2 mm x 40 mm. Through simulation and experiment of the new extended format emitter, we have determined that focusing the electron beam is limited due to the angular spread of the emitted electrons. This dispersion effect can be reduced through modification of the electron gun geometry, but this reduces the current reaching the ionization region. By increasing the transmission efficiency of the electron beam to the anode, we have increased the anode current by two orders of magnitude to realize a corresponding enhancement in instrument sensitivity, at a moderate cost to mass resolution. We will report recent experimental and

  3. 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…

  4. Gun Safety (For Kids)

    Science.gov (United States)

    ... hands. Even though guns are featured in many television shows, video games, computer games, and movies, it's ... feels safe. One thing to remember about gun violence at school is that it doesn't happen ...

  5. Low power microwave tests on RF gun prototype of the Iranian Light Source Facility

    Directory of Open Access Journals (Sweden)

    A Sadeghipanah

    2017-08-01

    Full Text Available In this paper, we introduce RF electron gun of Iranian Light Source Facility (ILSF pre-injection system. Design, fabrication and low-power microwave tests results of the prototype RF electron gun have been described in detail. This paper also explains the tuning procedure of the prototype RF electron gun to the desired resonant frequency. The outcomes of this project brighten the path to the fabrication of the RF electron gun by the local industries  

  6. Guns and sleep

    Directory of Open Access Journals (Sweden)

    Quan SF

    2015-08-01

    Full Text Available No abstract available. Article truncated at 150 words. Gun deaths are a problem in America. Irrespective of one’s position on gun control, the statistics do not lie. According to the Centers for Disease Control and Prevention (CDC, there were 11,208 deaths caused by firearms in 2013 (1. The recent high profile cases in Cincinnati, OH, Lafayette, LA and Memphis, TN further highlight the issue. Obviously, each case of death by a firearm had its own set of underlying factors that contributed to the final fatal outcome, but one wonders whether sleep deprivation can be implicated in some of them. Sleep duration in adults over the past approximately 30 years has been declining in the United States (2. A variety of reasons can be cited as underlying causes such as greater use of artificial lighting, an expanding 24 hour non-stop society, promotion of a work ethic that values “burning the midnight oil”, and use of electronic devices before bedtime ...

  7. 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.

  8. Low emittance design of the electron gun and the focusing channel of the Compact Linear Collider drive beam

    Science.gov (United States)

    Dayyani Kelisani, M.; Doebert, S.; Aslaninejad, M.

    2017-04-01

    For the Compact Linear Collider project at CERN, the power for the main linacs is extracted from a drive beam generated from a high current electron source. The design of the electron source and its subsequent focusing channel has a great impact on the beam dynamic considerations of the drive beam. We report the design of a thermionic electron source and the subsequent focusing channels with the goal of production of a high quality beam with a very small emittance.

  9. Theoretical analysis and simulation of the influence of self-bunching effects and longitudinal space charge effects on the propagation of keV electron bunch produced by a novel S-band Micro-Pulse electron Gun

    Science.gov (United States)

    Zhao, Jifei; Lu, Xiangyang; Zhou, Kui; Yang, Ziqin; Yang, Deyu; Luo, Xing; Tan, Weiwei; Yang, Yujia

    2016-06-01

    As an important electron source, Micro-Pulse electron Gun (MPG) which is qualified for producing high average current, short pulse, low emittance electron bunches steadily holds promise to use as an electron source of Coherent Smith-Purcell Radiation (CSPR), Free Electron Laser (FEL). The stable output of S-band MPG has been achieved in many labs. To establish reliable foundation for the future application of it, the propagation of picosecond electron bunch produced by MPG should be studied in detail. In this article, the MPG which was working on the rising stage of total effective Secondary Electron Yield (SEY) curve was introduced. The self-bunching mechanism was discussed in depth both in the multipacting amplifying state and the steady working state. The bunch length broadening induced by the longitudinal space-charge (SC) effects was investigated by different theoretical models in different regions. The 2D PIC codes MAGIC and beam dynamic codes TraceWin simulations were also performed in the propagation. The result shows an excellent agreement between the simulation and the theoretical analysis for bunch length evolution.

  10. Theoretical analysis and simulation of the influence of self-bunching effects and longitudinal space charge effects on the propagation of keV electron bunch produced by a novel S-band Micro-Pulse electron Gun

    Directory of Open Access Journals (Sweden)

    Jifei Zhao

    2016-06-01

    Full Text Available As an important electron source, Micro-Pulse electron Gun (MPG which is qualified for producing high average current, short pulse, low emittance electron bunches steadily holds promise to use as an electron source of Coherent Smith-Purcell Radiation (CSPR, Free Electron Laser (FEL. The stable output of S-band MPG has been achieved in many labs. To establish reliable foundation for the future application of it, the propagation of picosecond electron bunch produced by MPG should be studied in detail. In this article, the MPG which was working on the rising stage of total effective Secondary Electron Yield (SEY curve was introduced. The self-bunching mechanism was discussed in depth both in the multipacting amplifying state and the steady working state. The bunch length broadening induced by the longitudinal space-charge (SC effects was investigated by different theoretical models in different regions. The 2D PIC codes MAGIC and beam dynamic codes TraceWin simulations were also performed in the propagation. The result shows an excellent agreement between the simulation and the theoretical analysis for bunch length evolution.

  11. Theoretical analysis and simulation of the influence of self-bunching effects and longitudinal space charge effects on the propagation of keV electron bunch produced by a novel S-band Micro-Pulse electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jifei; Lu, Xiangyang, E-mail: xylu@pku.edu.cn; Yang, Ziqin; Yang, Deyu; Tan, Weiwei; Yang, Yujia [Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, 100871 (China); Zhou, Kui; Luo, Xing [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-06-15

    As an important electron source, Micro-Pulse electron Gun (MPG) which is qualified for producing high average current, short pulse, low emittance electron bunches steadily holds promise to use as an electron source of Coherent Smith-Purcell Radiation (CSPR), Free Electron Laser (FEL). The stable output of S-band MPG has been achieved in many labs. To establish reliable foundation for the future application of it, the propagation of picosecond electron bunch produced by MPG should be studied in detail. In this article, the MPG which was working on the rising stage of total effective Secondary Electron Yield (SEY) curve was introduced. The self-bunching mechanism was discussed in depth both in the multipacting amplifying state and the steady working state. The bunch length broadening induced by the longitudinal space-charge (SC) effects was investigated by different theoretical models in different regions. The 2D PIC codes MAGIC and beam dynamic codes TraceWin simulations were also performed in the propagation. The result shows an excellent agreement between the simulation and the theoretical analysis for bunch length evolution.

  12. Ultra-High-Vacuum Problem for 200 keV Polarized Electron Gun with NEA-GaAs Photocathode

    CERN Document Server

    Nakanishi, T; Kuwahara, M; Naniwa, K; Okumi, S; Yamamoto, M; Yamamoto, N; Yasui, K

    2004-01-01

    For a polarized electron source based on photoemission from GaAs, a NEA (Negative Electron Affinity) surface makes an indispensable role to extract polarized electrons in conduction band into vacuum. The NEA surface is also considered as a best surface to provide a beam with a minimum initial beam-emittance. However, the NEA surface state is realized by a mono-layer of electric dipole moment (that is Ga(-)-Cs(+)) formed at the surface and thus it is easily degraded by desorption of harmful residual gas, desorption of harmful gas created by field emission from HV-cathodes and ion back-bombardment. In order to reduce the effects of (a) and (c), extremely good UHV is required. Presently total pressure of 4·10-12

  13. Piercing and Tattoos - Multiple Languages: MedlinePlus

    Science.gov (United States)

    ... Home → Multiple Languages → All Health Topics → Piercing and Tattoos URL of this page: https://medlineplus.gov/languages/ ... XYZ List of All Topics All Piercing and Tattoos - Multiple Languages To use the sharing features on ...

  14. Research on Electrostatic Self-focusing Lanthanum Hexaboride Electron Gun%静电自会聚六硼化镧电子枪的研究

    Institute of Scientific and Technical Information of China (English)

    林祖伦; 王小菊; 祁康成; 曹贵川; 于海波

    2015-01-01

    设计并制作了一种用于X射线管的电子枪。以具有优异电子发射能力的六硼化镧阴极代替传统钨阴极,采用石墨热子加热的夹持式阴极结构;电子光学系统采用静电自聚焦方式,设计了具有梯形聚焦槽的单圆筒电极聚焦结构,避免了聚焦电极的引出;完成了阴极罩、阴极筒以及陶瓷芯柱等阴极组件的设计与封接。测试结果表明,当六硼化镧阴极为4.5 mm×0.8 mm的平面发射体结构时,在阴极温度1500℃,阴阳极间距3.5 mm,阳极电压2500 V条件下,热发射电流达到65 mA,且发射稳定性良好。在120 kV阳极电压下,电子枪在X射线样管中的性能测试结果表明,样管具有良好的电压电流开关特性,验证了该电子枪用于X射线管的优越性。%An electron gun for X-ray tube is designed and produced. The clamping type lanthanum hexaboride cathode with graphite heater is used in replace of the traditional tungsten cathode owing to its excellent electron emission ability. To avoid the leads of focusing electrode, we design a single focusing electrode with a trapezoidal focusing groove and a rectangular hole. Finally, other cathode structures such as cathode cover, cathode support and insulating ceramics are designed and the assembling of electron emitting system is completed. Thermionic emission test shows that when the lanthanum hexaboride emitting area is 4.5 mm×0.8 mm, the temperature of cathode is 1500 ℃, and the distance between anode and cathode is 3.5 mm, the anode current is 65 mA at anode voltage of 2 500 V, and the emission stability is excellent. The test of the X-ray tube based on lanthanum hexaboride electron gun shows that favorable switching performance is obtained at anode voltage of 120 kV.

  15. Transient effects in beam-plasma interactions in a space simulation chamber stimulated by a fast pulse electron gun

    Science.gov (United States)

    Raitt, W. J.; Banks, P. M.; Denig, W. F.; Anderson, H. R.

    1982-01-01

    Interest in the interaction of electron beams with plasma generated by ionization caused by the primary electron beam was stimulated by the need to develop special vacuum tubes to operate in the kMHz frequency region. The experiments of Getty and Smullin (1963) indicated that the interaction of an energetic electron beam with its self-produced plasma resulted in the emission of wave energy over a wide range of frequencies associated with cyclotron and longitudinal plasma instabilities. This enhanced the thermal plasma density in the vicinity of the beam, and the term Beam-Plasma Discharge (BPD) was employed to described this phenomenon. The present investigation is concerned with some of the transient phenomena associated with wave emission during the beam switch-on and switch-off periods. Results are presented on the changes in electron energy spectra on a time scale of tens of milliseconds following beam switch-on. The results are discussed in terms of the beam plasma discharge phenomenon.

  16. Development of TEM and SEM high brightness electron guns using cold-field emission from a carbon nanotip

    Energy Technology Data Exchange (ETDEWEB)

    Houdellier, F.; Knoop, L. de; Gatel, C.; Masseboeuf, A. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Mamishin, S.; Taniguchi, Y. [Hitachi High-Technologies Corporation, 882, Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Delmas, M.; Monthioux, M.; Hÿtch, M.J.; Snoeck, E. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France)

    2015-04-15

    A newly developed carbon cone nanotip (CCnT) has been used as field emission cathode both in low voltage SEM (30 kV) electron source and high voltage TEM (200 kV) electron source. The results clearly show, for both technologies, an unprecedented stability of the emission and the probe current with almost no decay during 1 h, as well as a very small noise (rms less than 0.5%) compared to standard sources which use tungsten tips as emitting cathode. In addition, quantitative electric field mapping around the FE tip have been performed using in situ electron holography experiments during the emission of the new tip. These results show the advantage of the very high aspect ratio of the new CCnT which induces a strong enhancement of the electric field at the apex of the tip, leading to very small extraction voltage (some hundred of volts) for which the field emission will start. The combination of these experiments with emission current measurements has also allowed to extract an exit work function value of 4.8 eV. - Highlights: • We develop a new field emission cathode based on carbon material. • We determine the exit work function of this new cathode using a combination of in situ electron holography and finite element modeling. • We show that the stability of cold-field emitted current can be improved with no decay during one hour of emission with a lower emission noise (less than 0.5%). • We used this cathode both for 200 kV TEM and 30 kV SEM cold field emission source. • As a TEM source, we also observe an increase of the spatial coherence using Fresnel fringes contrast.

  17. Rules of Appointment at Franklin Pierce College.

    Science.gov (United States)

    Franklyn Pierce Coll., Rindge, NH.

    This memorandum sets forth the regulations and procedures affecting appointments to the instructional faculty of Franklin Pierce College. Part A: General Provisions, includes information on faculty ranks, the procedure of appointment, the regular review, and normal retirement. Part B deals with the terms and conditions of appointment, including…

  18. Franklin Pierce College's Fire Department: 17 Student Volunteers and a Vintage Engine.

    Science.gov (United States)

    Meyer, Thomas J.

    1985-01-01

    Seventeen student volunteers form the Franklin Pierce College Fire Department. When the firefighters are on duty, they must carry electronic pagers at all times. They also participate in dormitory inspections and attend weekend sessions at a local firefighters' training school. (MLW)

  19. 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…

  20. A Very Fast Pulsed Electron Gun for (e, 2e) and (e, 3e) Studies

    Institute of Scientific and Technical Information of China (English)

    CaoShiping; MaXinwen; ShaShan; ZhuXiaolong; LiuHuipin

    2003-01-01

    Reaction microscope is a powerful tool for studying ion-atom/molecule dynamics, it can also be employed to investigate electron impact ionization processes. Traditionally these processes are studied by using the (e, 2e) or (e, 3e) techniques, most data are collected for single ionization and for very small scattering angles, i.e. (e, 2e), experimental data of double ionization (e, 3e)[1] and multiple ionization are scarce, because in most cases the efficiencies (mainly determined by solid angles) are extremely small for (e, 3e) processes, about 10-7~10-9. On the other hand, the new technique-reaction microscope can detect mutli-fragments in one collision with very

  1. The Missing Gun The Missing Gun

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ma Shan, a criminal poljceman in a remotesmall town in the southwestern Yunnan province,gets drunk at his sister’s wedding and has his three-bullet gun lost, He tries to find it stealthily but endsup in vain. He has tno choice but to report the

  2. Ultra-low emittance X-band photocathode RF gun

    Institute of Scientific and Technical Information of China (English)

    TANG Chuan-Xiang; LIU Xiao-Han

    2009-01-01

    In this paper,we present the simulation results of a 1.6 cell X-band photocathode RF gun for ultra-low emittance electron beams.It will work at 9.3 GHz.The emittance,bunch length,electron energy and energy spread at the gun exit are optimized at bunch charge of 1pC using PARMELA.Electron bunches type coupler is adopted in this gun and an initial simulation by MAFIA is also given in this paper.

  3. Progress of the Rossendorf SRF Gun Project

    CERN Document Server

    Teichert, J; Büttig, H; Janssen, D; Lehnert, U; Michel, P; Möller, K; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Xiang, R

    2005-01-01

    A superconducting rf photo electron injector (SRF gun) is under development at the Forschungszentrum Rossendorf. The project aims at several issues: improvement of the beam quality for the ELBE superconducting electron linac, demonstration of feasibility of this gun type, investigation of critical components, and parameter studies for future application (BESSY-FEL, 4GLS). In 2005, a substantial progress has been made. The two 3.5-cell niobium cavities for the gun have been delivered from the company ACCEL. The main parts for gun cryostat like vacuum vessel, cryogenic and magnetic shields are ready. Test benches for the cathode cooling system and the cavity tuner are being assembled. The photo cathode preparation lab has been arranged, and the diagnostic beam line has been designed (see T. Kamps et al., this conference). After delivering the gun cavities, their rf properties are being measured at room temperature and the warm tuning is being carried out. The set-up for this treatment and measurement as well as...

  4. Modeling and Optimization for Piercing Energy Consumption

    Institute of Scientific and Technical Information of China (English)

    XIAO Dong; PAN Xiao-li; YUAN Yong; MAO Zhi-zhong; WANG Fu-li

    2009-01-01

    Energy consumption is an important quality index in the production of seamless tubes. The complex factors affecting energy consumption make it difficult to build its mechanism model, and optimization is also very difficult, if not impossible. The piercing process was divided into three parts based on the production process, and an energy consumption prediction model was proposed based on the step mean value staged multiway partial least square meth-od. On the basis of the batch process prediction model, a genetic algorithm was adopted to calculate the optimum mean value of each process parameter and the minimum piercing energy consumption. Simulation proves that the op-timization method based on the energy consumption prediction model can obtain the optimum process parameters ef-fectively and also provide reliable evidences for practical production.

  5. Status of the SRF Gun Operation at ELBE

    CERN Document Server

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, Ch; Schurig, R; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I; Staufenbiel, F

    2010-01-01

    The superconducting RF photo-injector (SRF gun) at FZD is the first operating electron injector of its kind. The gun with a 3½-cell cavity and a frequency of 1.3 GHz produces an electron beam of 3 MeV with a maximum bunch charge of about 400 pC. Also the design values for the acceleration gradient could not be reached with the cavity which is in use at present, the SRF gun will improve the beam quality for ELBE users. In the winter shutdown of 2009/10 the beam line was installed which connects the SRF gun with the ELBE accelerator. The paper reports on the first tests and on the progress in applying the SRF gun for ELBE operation.

  6. 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...

  7. Teen Suicide and Guns

    Science.gov (United States)

    ... Issues Listen Text Size Email Print Share Teen Suicide and Guns Page Content Article Body Protect Your ... of a passing problem, not the outcome! Teen Suicide—A Big Problem Suicide is one of the ...

  8. Tongue piercing by a Yogi: QEEG observations.

    Science.gov (United States)

    Peper, Erik; Wilson, Vietta E; Gunkelman, Jay; Kawakami, Mitsumasa; Sata, Misa; Barton, William; Johnston, James

    2006-12-01

    : This study reports on the QEEG observations recorded from a yogi during tongue piercing in which he demonstrated voluntary pain control. The QEEG was recorded with a Lexicor 1620 from 19 sites with appropriate controls for impedence and artifacts. A neurologist read the data for abnormalities and the QEEG was analyzed by mapping, single and multiple hertz bins, coherence, and statistical comparisons with a normative database. The session included a meditation baseline and tongue piercing. During the meditative baseline period the yogi's QEEG maps suggesting that he was able to lower his brain activity to a resting state. This state showed a predominance of slow wave potentials (delta) during piercing and suggested that the yogi induced a state that may be similar to those found when individuals are under analgesia. Further research should be conducted with a group of individuals who demonstrate exceptional self-regulation to determine the underlying mechanisms, and whether the skills can be used to teach others how to manage pain.

  9. Gun Control Legislation

    Science.gov (United States)

    2010-08-27

    issue for the 111th Congress has been gun trafficking and smuggling across the Southwest border from the United States to Mexico .4 Several...committees have held hearings on gun trafficking and smuggling across the Southwest border from the United States to Mexico . In the Consolidated...emerging technology by which a firearm’s serial number is engraved microscopically with a laser onto the breech face or firing pin of a firearm. When

  10. Crafting a Gauss Gun Demonstration

    Science.gov (United States)

    Blodgett, Matthew E.; Blodgett, E. D.

    2006-12-01

    A Gauss Gun launches a ferromagnetic projectile using a pulsed electromagnet. This demonstration provides a nice counterpoint to the popular Thompson's jumping ring demonstration, which launches a nonferromagnetic ring via repulsion of an induced current. The pulsed current must be short enough in duration so that the projectile is not retarded by lingering current in the launch solenoid, but also large enough to provide a suitably impressive velocity. This project involved an iterative design process, as we worked through balancing all the different design criteria. We recommend it as a very nice electronics design project which will produce a very portable and enjoyable demonstration. AAPT sponsor Earl Blodgett.

  11. Design of a high repetition rate S-band photocathode gun

    Science.gov (United States)

    Han, Jang-Hui; Cox, Matthew; Huang, Houcheng; Pande, Shivaji

    2011-08-01

    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.

  12. 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.

  13. Electromagnetic configurations of rail guns

    Science.gov (United States)

    Fat'yanov, O. V.; Ostashev, V. E.; Lopyrev, A. N.; Ul'Yanov, A. V.

    1993-06-01

    Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect of the ohmic resistance of the electrodes and of the additional magnetization field on the spatial structure of the discharge in the rail gun channel is discussed. A classification of rail gun modifications is presented.

  14. Self-piercing riveting properties, processes and applications

    CERN Document Server

    Chrysanthou, A

    2014-01-01

    Due to its speed, low energy requirements, and the fact that it does not require a pre-drilled hole, the technique of self-piercing riveting (SPR) has been increasingly adopted by many industries as a high-speed mechanical fastening technique for the joining of sheet material components. Self-piercing riveting comprehensively reviews the process, equipment, and corrosion behaviour of self-piercing riveting, and also describes the process of evaluation and modelling of strength of self-piercing riveted joints, quality control methods and non-destructive testing.Part one provides an exte

  15. Injury risk of nonpowder guns.

    Science.gov (United States)

    Laraque, Danielle

    2004-11-01

    Nonpowder guns (ball-bearing [BB] guns, pellet guns, air rifles, paintball guns) continue to cause serious injuries to children and adolescents. The muzzle velocity of these guns can range from approximately 150 ft/second to 1200 ft/second (the muzzle velocities of traditional firearm pistols are 750 ft/second to 1450 ft/second). Both low- and high-velocity nonpowder guns are associated with serious injuries, and fatalities can result from high-velocity guns. A persisting problem is the lack of medical recognition of the severity of injuries that can result from these guns, including penetration of the eye, skin, internal organs, and bone. Nationally, in 2000, there were an estimated 21840 (coefficient of variation: 0.0821) injuries related to nonpowder guns, with approximately 4% resulting in hospitalization. Between 1990 and 2000, the US Consumer Product Safety Commission reported 39 nonpowder gun-related deaths, of which 32 were children younger than 15 years. The introduction of high-powered air rifles in the 1970s has been associated with approximately 4 deaths per year. The advent of war games and the use of paintball guns have resulted in a number of reports of injuries, especially to the eye. Injuries associated with nonpowder guns should receive prompt medical management similar to the management of firearm-related injuries, and nonpowder guns should never be characterized as toys.

  16. RF gun for an intense THz radiation source

    Institute of Scientific and Technical Information of China (English)

    GU Qiang; ZHAO Zhen-Tang; TONG De-Chun; CHEN Li-Fang; XU Xiu-Min

    2008-01-01

    A new facility is under construction at the Shanghai Institute of Applied Physics,to generate femto-second electron bunches and intense coherent THz radiation pulses.A thermionic RF-gun is used to be the electron source of the linac,which is 1.6 cell,π/2,side coupled in design.In the following of this paper,the design,manufacture and beam operation of this gun are presented.

  17. Obituary: A. Keith Pierce, 1918 - 2005

    Science.gov (United States)

    Livingston, William Charles

    2006-12-01

    A. Keith Pierce was a solar astronomer who will be remembered for bringing the physics lab to the telescope and for his design of the world's largest solar telescope, the 1.5-meter McMath Telescope on Kitt Peak in Arizona. Born in Lincoln, Nebraska, he died of cancer in Tucson on 11 March 2005. He was eighty-six. His father, Tracy Pierce, had gone to graduate school in Berkeley, California, with a major in mathematics and a minor in astronomy. Fellow students of his class included Seth Nicholson and Donald Shane, people who were later to influence young Keith's life. Tracy Pierce received an appointment as an instructor, later Professor, of mathematics at the University of Nebraska in Lincoln. In his spare time dad Tracy became something of a telescope nut, following "the bible" —Albert Ingall's A.T.M (Amateur Telescope Making). His enthusiasm rubbed off on his son. Seth Nicholson, who became a famous Mt. Wilson Observatory astronomer, and Donald Shane from Berkeley, both stayed at the Pierce home while on their Sigma Xi lecture tours. After two years at Lincoln, followed by two more at Berkeley, Keith had earned his bachelor's degree in astronomy. During World War II, Dr. Shane became personnel director at the E.O. Lawrence Radiation Lab and arranged for Keith to work there at the cyclotron. A crash program to produce U235 from U238 was under way. At a crucial point in 1942 the cyclotron turned out the sought-after material. Much celebration ensued among the Rad Lab leaders. During this gala, Keith was on the night-shift and pretty much on his own. It was then that he turned a valve to the right, when left was called for, and the entire system went down. Shortly thereafter he was sent to Oak Ridge for the duration of the war. He cannot have been thought of badly, however, because he was invited to the Trinity test in New Mexico. (He didn't go because of the pending birth of his first son, John.) The year 1945 found Keith back in Berkeley working on his Ph

  18. 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

  19. 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

  20. Julianne Pierce VNS Matrix / Julianne Pierce ; interv. Tilman Baumgärtel

    Index Scriptorium Estoniae

    Pierce, Julianne

    2006-01-01

    Intervjuu austraalia kunstniku Julianne Pierce'iga, kes koos Josephine Starrsi, Francesca da Rimini ja Virginia Barretiga lõi 1991. a. Sydney's naiskunstirühmituse VNS Matrix ning kirjutas "21. sajandi küberfeministliku manifesti". Rühmituse töödest

  1. Julianne Pierce VNS Matrix / Julianne Pierce ; interv. Tilman Baumgärtel

    Index Scriptorium Estoniae

    Pierce, Julianne

    2006-01-01

    Intervjuu austraalia kunstniku Julianne Pierce'iga, kes koos Josephine Starrsi, Francesca da Rimini ja Virginia Barretiga lõi 1991. a. Sydney's naiskunstirühmituse VNS Matrix ning kirjutas "21. sajandi küberfeministliku manifesti". Rühmituse töödest

  2. 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...

  3. Middle ground on gun control

    OpenAIRE

    Stewart, Peter A.

    2016-01-01

    Approved for public release; distribution is unlimited Each tragic shooting incident that the American news media covers highlights the problem of gun violence in the United States. However, the focus of this reporting is rarely on the largest component of total gun deaths: suicides. Suicides make up two-thirds of all gun deaths. Limiting access to firearms for individuals with suicidal tendencies could cause a significant reduction in the total number of casualties included in gun violenc...

  4. 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…

  5. Remoção do piercing no perioperatório Remoción del piercing en el perioperatorio Perioperative removal of body piercing

    Directory of Open Access Journals (Sweden)

    Solange Diccini

    2008-02-01

    Full Text Available A permanência do piercing no intra-operatório pode ocasionar intercorrências. Este estudo teve como objetivo determinar as intervenções de enfermagem no pré-operatório e avaliar as complicações do piercing no intra-operatório. Durante a revisão da literatura, foram incluídos 16 artigos publicados de 1994 a 2006. Nove artigos (56,2% de intervenções de enfermagem no pré-operatório, quatro (25,0% de complicações do piercing no intra-operatório e três (18,8% sobre o uso do piercing no intra-operatório, não apresentando complicações. Concluímos que a presença de piercing oral durante o intra-operatório aumenta o risco de lesões e aspiração. No corpo, a presença do piercing pode causar lesões na pele, decorrentes da mobilização do paciente e queimaduras eletrocirúrgicas. Portanto, é necessária a retirada do piercing no pré-operatório.La permanencia del piercing en el intraoperatorio puede causar algún perjuicio. Pretendemos, determinar las intervenciones de enfermería en el preoperatorio y evaluar las complicaciones del piercing en el intraoperatorio. La revisión de la literatura mostró 16 artículos publicados de 1994 a 2006. Nueve (56,2% fueron de intervenciones de enfermería en el preoperatorio, cuatro (25,0% de complicaciones del piercing en intraoperatorio, tres (18,8% no mostraron complicaciones. Concluimos, la presencia del piercing oral, durante el intraoperatório aumenta el riesgo de aspiración y daño. En el cuerpo, puede causar heridas en la piel, provocadas por la movilización del enfermo y las quemaduras, debido al uso de bisturí eléctrico durante el acto intraoperatorio. Por consiguiente, es necesario retirar el piercing en el preoperatorio.The remaining of piercing in intraoperative can cause damages. This paper had as purpose defining the nursing interventions in the intraoperative and evaluates the complications caused by piercing in the intraoperative. This literature review had 16

  6. Emittance studies at the Los Alamos National Laboratory Free-Electron Laser (FEL)

    Science.gov (United States)

    Carlsten, B. E.; Feldman, D. W.; Lumpkin, A. H.; Stein, W. E.; Warren, R. W.

    Recent emittance studies at the Los Alamos Free-Electron Laser (FEL) have indicated several areas of concern in the linac and beamline feeding the wiggler. Four emittance growth mechanisms of special importance have been studied. First, a rapid growth of the electron beam's emittance immediately after the spherical gridded Pierce gun resulted, in part, from the long time required for our pulsing electronics to ramp the grid voltage up at the start and down at the end of the pulse, which created a pulse with a cosine-like current distribution as a function of time. The growth was compounded by the extremely small radial beam size (almost a waist) leaving the gun. In addition, we saw evidence of electrostatic charging of the insulators in the gun, reducing the quality of the electron beam further. Second, the action of the solenoidal focusing fields in the low-voltage bunching region was studied, and criteria for a minimum emittance growth were established. Third, maximum misalignment angles and displacements for various elements of the beamline were calculated for the desired low emittance growth. Finally, emittance growth in the horizontal dimension through the nonisochronous bend caused by varying energy depression on the particles due to longitudinal wake fields was both calculated and observed. In addition, we measured energy depressions caused by the wake fields generated by various other elements in the beamline. Strategies were developed to relieve the magnitude of these wake-field effects.

  7. Oral Piercing and Oral Diseases: A Short Time Retrospective Study

    Directory of Open Access Journals (Sweden)

    Francesco Inchingolo, Marco Tatullo, Fabio M. Abenavoli, Massimo Marrelli, Alessio D. Inchingolo, Antonio Palladino, Angelo M. Inchingolo, Gianna Dipalma

    2011-01-01

    Full Text Available Body piercing indicates the puncturing of a part of the body in which jewelry may be worn. In recent years, oral piercing is increasingly popular especially among young people. Body piercing has to be considered as a surgical procedure to all intents and purposes and, as such, has to be performed only by qualified personnel able to assure high standards of professionalism in facilities subject to sanitary inspections.The aim of the present work is to verify what risks patients may be exposed to and what complications may occur after a healthcare professional performs oral piercing.Our retrospective study includes 108 patients (74 males and 34 females aged between 14 and 39 years, who had oral piercing done 12±4 months earlier. All the patients underwent clinical examination to reveal the possible presence of late complications. After piercing, none of the 108 patients developed widespread complications.Although all patients said they had followed the piercers' instructions, 96% of them reported postoperative local complications such as bleeding within 12 hours of piercing (90%, perilesional edema for 3±2 days after piercing surgery (80%, and persistent mucosal atrophy (70%.

  8. Management of Retained Genital Piercings: A Case Report and Review

    Directory of Open Access Journals (Sweden)

    Laura J. Moulton

    2017-01-01

    Full Text Available The prevalence of genital piercing among women is increasing. As the popularity increases, the number of complications from infection, injury, and retained jewelry is likely to rise. Techniques to remove embedded jewelry are not well described in the literature. The purpose of this report was to describe a case of a patient with a retained clitoral glans piercing, discuss a simple technique for outpatient removal, and review current evidence regarding associated risks of clitoral piercings. A 24-year-old female presented to the emergency department with an embedded clitoral glans piercing. Local anesthetic was injected into the periclitoral skin and a small superficial vertical incision was made to remove the ball of the retained barbell safely. In conclusion, among patients with retained genital piercing, outpatient removal of embedded jewelry is feasible. While the practice of female genital piercing is not regulated, piercing of the glans of the clitoris is associated with increased injury to the nerves and blood supply of the clitoris structures leading to future fibrosis and diminished function compared to piercing of the clitoral hood.

  9. Management of Retained Genital Piercings: A Case Report and Review

    Science.gov (United States)

    2017-01-01

    The prevalence of genital piercing among women is increasing. As the popularity increases, the number of complications from infection, injury, and retained jewelry is likely to rise. Techniques to remove embedded jewelry are not well described in the literature. The purpose of this report was to describe a case of a patient with a retained clitoral glans piercing, discuss a simple technique for outpatient removal, and review current evidence regarding associated risks of clitoral piercings. A 24-year-old female presented to the emergency department with an embedded clitoral glans piercing. Local anesthetic was injected into the periclitoral skin and a small superficial vertical incision was made to remove the ball of the retained barbell safely. In conclusion, among patients with retained genital piercing, outpatient removal of embedded jewelry is feasible. While the practice of female genital piercing is not regulated, piercing of the glans of the clitoris is associated with increased injury to the nerves and blood supply of the clitoris structures leading to future fibrosis and diminished function compared to piercing of the clitoral hood. PMID:28299217

  10. Tattoos and Piercings: Attitudes, Behaviors, and Interpretations of College Students

    Science.gov (United States)

    Horne, Jenn; Knox, David; Zusman, Jane; Zusman, Marty E.

    2007-01-01

    Previously, in those segments of America where "proper" behavior was valued, tattoos and body piercings were examples of what Goffman identified as "stigma"--they spoiled one's identity. Today, tattoos and piercings have become more mainstream. This study reports the survey of 400 undergraduates at a large southeastern university. Regarding…

  11. Serbian society and gun culture

    Directory of Open Access Journals (Sweden)

    Cvetković Vladimir

    2006-01-01

    Full Text Available This paper questions whether one characteristic of Serbian society is a gun culture. The first part of the paper deals with some theoretical concerns and closer explanation of what is understood by the term gun culture. Few different approaches to the issue are analyzed. The concept used has three main components of the gun culture: system of positive beliefs; social symbols embodied by the gun; agent "bearers" of gun culture. The second part of the paper presents results from Small Arms and Light Weapons survey conducted in 2004 in Serbia. The results were analyzed within the theoretical framework proposed in the first part of the paper.

  12. E-Gun Technology

    Science.gov (United States)

    1981-07-01

    AD E-GUN TECHNOLOGY N FINAL TECHNICAL REPORT J. E. Eninger , H. W. Friedman and K. E. Williams AVCO EVERETT RESEARCH LABORATORY, INC. Contract No...Report J.E. Eninger , H.W. Friedman and K.E. Williams AVCO EVERETT RESEARCH LABORATORY, INC. A Subsidiary of Avco Corporation 2385 Revere Beach Parkway

  13. The Rail Gun.

    Science.gov (United States)

    Stewart, Gay B.

    1996-01-01

    Presents a rail gun demonstration that addresses a broad group of educational goals in introductory electricity and magnetism. Uses a battery-powered circuit consisting of a movable conductor placed across two conducting rails in a magnetic field to review mechanics, foster approximate reasoning and lateral class discussion, and demonstrate the…

  14. 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.

  15. Giving Up the Gun.

    Science.gov (United States)

    LaRue, Robert D.

    1989-01-01

    Provides a model lesson from the book "Science/Technology/Society: Model Lessons for Secondary Social Studies Classes." Outlines Japan's campaign in the seventeenth and eighteenth centuries to rid itself of guns and return to swords. Provides background information and student handouts. (RW)

  16. RF Gun Photocathode Research at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Jongewaard, E.; Akre, R.; Brachmann, A.; Corbett, J.; Gilevich, S.; Grouev, K.; Hering, P.; P.Krejcik,; Lewandowski, J.; Loos, H.; Montagne, T.; Sheppard, J.C.; Stefan, P.; Vlieks, A.; Weathersby, S.; Zhou, F.; /SLAC

    2012-05-16

    LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

  17. Research on TiO2 scanning mode during E type electron gun evaporation plating%TiO2在e型电子枪蒸镀时扫描模式的研究

    Institute of Scientific and Technical Information of China (English)

    宋佳妮; 刘凯; 闫文平

    2015-01-01

    This article is mainly to research the TiO2 scan mode setting during evaporation e type electron gun , in order to adjust the TiO2 characteristics in the vacuum coating, guarantee the relatively stable good condition of TiO2 during the film deposition.%本文主要是对TiO2在e型电子枪蒸镀时的扫描模式设定进行了研究,以此来调整 TIO2在真空镀膜时的特性,保证TiO2在形膜过程中获得相对稳定的良好状态。

  18. Gun Attitudes and Fear of Crime.

    Science.gov (United States)

    Heath, Linda; Weeks, Kyle; Murphy, Marie Mackay

    1997-01-01

    Using three studies, examined the relationship between attitudes toward guns and fear of crime. Findings indicate a connection between fear of crime and attitudes toward guns: people higher in fear of crime favored gun control. Results also established a relationship between stereotypical beliefs about gun victims and support for gun control. (RJM)

  19. Application of hard coatings for blanking and piercing tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2011-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  20. Perceptions of a photograph of a woman with visible piercings.

    Science.gov (United States)

    Martino, Sara

    2008-08-01

    To examine perceptions of people with visible piercings 105 undergraduate students from four different courses on campus (85 women, 20 men; M age=20.0 yr., SD=3.4) were randomly assigned to rate a photograph of a women with or without piercings on her eyebrow, ear, lip, and nose on 13 characteristics. Analysis indicated the model with visible piercings was rated less religious and more creative, artistic, and mysterious. These findings differ from previous findings on perception of tattoos. Implications and directions for research with different age groups are discussed.

  1. 超快电子枪时间分辨率测量方法的理论研究%Theoretical Research on Time Resolution of the Ultra-fast Electron Gun

    Institute of Scientific and Technical Information of China (English)

    袁锡明; 吴建军; 田进寿; 李军科

    2011-01-01

    分析了处于扫描状态的超短脉冲电子束在超快电子枪中的传输特性;讨论并获得了一种特定配置的电子枪偏转电压对电子束偏转距离的影响并讨论了截获条件;分析了电子枪偏转电压对电子束到达荧光屏位置的偏转距离的影响,并得到了在扫描状态下电子束能够出现在直径30mm的荧光屏的有效范围内的条件.依据以上结论,分析了时间-空间转换测量法在测量fs量级的电子脉冲宽度时所遇到的新的难题,设计了一个调节效率较高的实验系统,以解决扫描斜坡电压信号和超快电子脉冲的同步.%The transmission characteristic of the ultra-short electron beams was analyzed when the electron gun was in the scan state, the deflection voltage influence on the deflection distance was discussed in a specific configuration,and the interception condition was obtained for the electron beams to be appeared inside the effective area of the phosphor screen. A conclusion was drawn that the initial deflection voltageshould be between +700~+1 140 volts. Based on those findings and conclusions,the measurement methodnamed time-to-spatial transfer was discussed, with the finding that it is a very difficult work for the synchronization of the electron and the optical signals. A new experiment system was designed to settle the synchronization problem of the scan slope voltage and the electron pulse in the electron gun.

  2. Improved performances of CIBER-X: a new tabletop laser-driven electron and x-ray source

    Science.gov (United States)

    Girardeau-Montaut, Jean-Pierre; Kiraly, Bela; Girardeau-Montaut, Claire

    2000-11-01

    We present the most recent data concerning the performances of the table-top laser driven electron and x-ray source developed in our laboratory. X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulse at 213 nm. The e-gun is a standard pierce diode electrode type, in which electrons are accelerated by a cw electric fields of 12 MV/m. The photoinjector produced a train of 90 - 100 keV electron pulses of approximately 1 nC and 40 A peak current at a repetition rate of 10 Hz. The electrons, transported outside the diode, are focused onto a target of thulium by magnetic fields produced by two electromagnetic coils to produce x-rays. Applications to low dose imagery of inert and living materials are also presented.

  3. Friction in rail guns

    Science.gov (United States)

    Kay, P. K.

    1984-01-01

    The influence of friction is included in the present equations describing the performance of an inductively driven rail gun. These equations, which have their basis in an empirical formulation, are applied to results from two different experiments. Only an approximate physical description of the problem is attempted, in view of the complexity of details in the interaction among forces of this magnitude over time periods of the order of milisecs.

  4. Keeping Naval Guns Ready

    Science.gov (United States)

    2016-03-01

    April 2016 22 Between 1990 and 2014, the world economy doubled, rising from $35 trillion to $75 trillion, lifting billions of people out of poverty ...surface combatants have been directed to conduct daily exercises, firing .50 caliber to 5-inch guns. Because of their extensive use in the severe...Mark 15 Close-In Weapon System, on all Navy surface combatant ships 23 Defense AT&L: March-April 2016 • 25 mm, Mark 38, on Navy aircraft

  5. 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.

  6. Air guns: toys or weapons?

    Science.gov (United States)

    Aslan, Sahin; Uzkeser, Mustafa; Katirci, Yavuz; Cakir, Zeynep; Bilir, Ozlem; Bilge, Fatih; Cakir, Murtaza

    2006-09-01

    Air guns and blank guns may appear relatively harmless at first glance, but they are, in fact, potentially destructive, even lethal, weapons. Approximately 2 to 2.5 million nonpowder firearms are sold annually, and again approximately 12.9 per 100,000 population are treated for such injuries in hospital emergency departments each year in the United States. Unfortunately, these guns are considered to be a toy for children. Therefore, incidents of air gun injuries are gradually increasing. Although such injuries may initially be considered trivial, it may signify severe internal tissue pathologies. These apparently trivial injuries may have catastrophic consequences if unnoticed. In this study, we report 4 cases with head injury due to a shot by these guns. The cases indicate that these people had used the guns belonging to their parents for the purpose of suicide. The cases also show that these machines are not innocent.

  7. CAPE TOWN'S TIME-GUNS

    Directory of Open Access Journals (Sweden)

    W.M. Bisset

    2012-02-01

    Full Text Available Although a great many articles have been written on the subject of Cape Town's noon gun (the. official terminology is 'time-gun' most of the writers have not had access to the Lion Battery Fort Record Book and the existance of more than one Cape Town time-gun has only recently been recorded. By 1807 a noon gun was fired regularly from the Imhoff Battery on the seaward side of the Castle.1 On 4 August 1902 the noon gun was fired from Lion Battery on Signal Hill for the first time.2 The battery was built because of fears of war with Russia and had been armed with two 9- inch Rifled Muzzle Loading guns by 1891. Lion Battery was remodelled in 1911.

  8. Ballistic evaluationof LOVA propellant in high calibre gun

    Directory of Open Access Journals (Sweden)

    A.G.S. Pillai

    2001-04-01

    Full Text Available 'This paper presents the data obrained on dynamic firing of a cellulose acetate binder-based low vulnerability ammunition (LOV A propellant using 120 mm fin-stabilised armour piercing discarding sabot (FSAPDS kinetic energyammunition. An optimised propellant composition formulated ~sing fine RDX as an energetic ingredient and a mixture of cellulose acetate and nitrocellulose as binder was qualified fit for firing in a high calibre gun by its successful static evaluation for absolute ballistics using high pressure closed vessel technique. Dynamic firing of the propellant processed in heptatubular geometry was undertaken to assess the propellant charge mass. This propellant achieved higher muzzle velocity as compared to the standard NQ/M119 triple-base propellant while meeting the non-vulnerability characteristics convincingly.

  9. Development of S-band photocathode RF guns at Tsinghua University

    Science.gov (United States)

    Zheng, Lianmin; Du, Yingchao; Zhang, Zhe; Qian, Houjun; Yan, Lixin; Shi, Jiaru; Zhang, Zhen; Zhou, Zheng; Wu, Xiaowei; Su, Xiaolu; Wang, Dong; Tian, Qili; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

    2016-10-01

    This study aims to explain the development of S-band photocathode RF guns at Tsinghua University, with especial attention on the progress of guns developed after 2011. Two types of RF guns were developed based on the BNL/SLAC/UCLA gun prior 2011. These guns have been operated as electron sources for Tsinghua Thomson scattering X-ray source (TTX), MeV ultrafast electron diffraction, and Shanghai deep ultraviolet FEL test facility. Based on our operation experiences and other gun modifications worldwide, numerous improvements have been proposed, and seven third-type guns have been designed and fabricated since 2011. Cold tests of all third-type guns have been completed, confirming a significantly improved quality factor and mode separation. The first third-type gun has been installed on TTX and operated for four years, demonstrating high gradient, low dark current, stable quantum efficiency, and small emittances. The optimal transverse emittance was εx = 0.56 mm mrad , εy = 0.66 mm mrad for 200 pC with a peak current of 25 A, and εx = 0.78 mm mrad , εy = 0.92 mm mrad for 500 pC with a peak current of 62.5 A under a 110 MV/m gun gradient.

  10. Pierce Lumber, Inc. - Clean Water Act Public Notice

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Pierce Lumber, Inc. (“Respondent”), located at 1629 13th Street, Belle Plaine, IA for alleged violations of its National Pollutant Discharge Elimination System permit (perm

  11. Pierce National Wildlife Refuge: Narrative Report: 1992: Calendar Year

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Pierce National Wildlife Refuge outlines Refuge accomplishments for the 1992 calendar year. The report begins by giving Refuge highlights...

  12. Cold Test Measurements on the GTF Prototype RF Gun

    Energy Technology Data Exchange (ETDEWEB)

    Gierman, S.M.

    2010-12-03

    The SSRL Gun Test Facility (GTF) was built to develop a high brightness electron injector for the LCLS and has been operational since 1996. Based on longitudinal phase space measurements showing a correlated energy spread the gun was removed and re-characterized in 2002. The low power RF measurements performed on the gun are described below. Perturbative bead measurements were performed to determine the field ratio in the two-cell gun, and network analyzer measurements were made to characterize the mode structure. A second probe was installed to monitor the RF field in the first cell, and a diagnostic was developed to monitor the high-power field ratio. Calibration of the RF probes, a model for analyzing RF measurements, and Superfish simulations of bead and RF measurements are described.

  13. X射线源的静电自会聚电子枪的计算机模拟%Simulation of Electrostatic Self-Focusing Lanthanum Hexaboride Electron Gun Applied in X-Ray Source

    Institute of Scientific and Technical Information of China (English)

    于海波; 林祖伦; 祁康成; 曹贵川; 王小菊

    2015-01-01

    High power, high current density, fine focus X-ray sources are widely used in the field of industrial nondestructive testing, medical imaging, security technology, and so on. An electrostatic self-focusing lanthanum hexaboride electron gun applied in X-ray source is designed using electron beam simulation (EBS) software. The electron gun consists of three parts: a lanthanum hexaboride thermionic emitter, a focusing electrode with a trapezoidal focusing groove and a rectangular hole, and an anode. The simulated results show that the inclination angle of focusing electrode has strong influence on electron focusing property and the best inclination angle is 46°. The anode current and the uniformity of the distribution are decreased with increasing the distance between the gate and cathode, and the best distance between the gate and cathode value is 0.3 mm.%高功率、大电流密度、细聚焦X射线源在工业无损探伤、医学成像、安全技术等领域具有广泛的应用。本文设计了一种用于X射线管的静电自会聚电子枪,该电子枪包括三部分:LaB6热阴极发射体、带有矩形孔和斜槽的聚焦极、阳极。采用EBS粒子束模拟软件对该电子枪的结构进行了模拟仿真。仿真结果表明:电子枪的聚焦能力主要取决于聚焦极倾角,当聚焦极倾角为46°时,达到理想的电子束聚焦效果;随着阴栅距的增加,阳极电流以及束斑电流分布均匀性显著降低,当阴栅距为0.3 mm,可在工艺条件允许下,得到具有较大阳极电流以及理想电流分布的电子束。

  14. Drawing Euler Diagrams with Circles: The Theory of Piercings.

    Science.gov (United States)

    Stapleton, Gem; Leishi Zhang; Howse, John; Rodgers, Peter

    2011-07-01

    Euler diagrams are effective tools for visualizing set intersections. They have a large number of application areas ranging from statistical data analysis to software engineering. However, the automated generation of Euler diagrams has never been easy: given an abstract description of a required Euler diagram, it is computationally expensive to generate the diagram. Moreover, the generated diagrams represent sets by polygons, sometimes with quite irregular shapes that make the diagrams less comprehensible. In this paper, we address these two issues by developing the theory of piercings, where we define single piercing curves and double piercing curves. We prove that if a diagram can be built inductively by successively adding piercing curves under certain constraints, then it can be drawn with circles, which are more esthetically pleasing than arbitrary polygons. The theory of piercings is developed at the abstract level. In addition, we present a Java implementation that, given an inductively pierced abstract description, generates an Euler diagram consisting only of circles within polynomial time.

  15. Weight of RCL Guns in Comparison to Conventional Guns

    Directory of Open Access Journals (Sweden)

    J. P. Sirpal

    1956-07-01

    Full Text Available A study has been made of the weight of ordnance and equipment for a given performance. The comparative weights of the RCL and the orthodox equipments have been studied and it has been found that for the same muzzle energy the weight of RCL gun is 1/4th that of orthodox gun.

  16. Diagnostics Beamline for the SRF Gun Project

    CERN Document Server

    Kamps, T; Goldammer, K; Krämer, Dietrich; Kuske, P; Kuszynski, J; Lipka, D; Marhauser, F; Quast, T; Richter, R

    2005-01-01

    A superconducting rf photo electron injector (SRF gun) is currently under construction by a collaboration between BESSY, DESY, FZR and MBI. The project aims at the design and setup of an CW SRF gun including a diagnostics beamline for the ELBE FEL and to address R&D issues on low emittance injectors for future light sources such as the BESSY FEL. Of critical importance for the injector performance is the control of the electron beam parameters. For this reason a compact diagnostics beamline is under development serving a multitude of operation settings ranging from low-charge (77pC), low-emittance (1 pi mm mrad) mode to high-charge (2.5nC) operation of the gun. For these operation modes beam dynamics simulations are resulting in boundary conditions for the beam instrumentation. Proven and mature technology is projected wherever possible, for example for current and beam position monitoring. The layout of the beam profile and emittance measurement systems is described. For the bunch length, which varies be...

  17. Diagnostics Beamline for the SRF Gun Project

    Energy Technology Data Exchange (ETDEWEB)

    T. Kamps; V. Durr; K. Goldammer; D. Kramer; P. Kuske; J. Kuszynski; D. Lipka; F. Marhauser; T. Quast; D. Richter; U. Lehnert; P. Michel; J. Teichert; P. Evtushenko; I. Will

    2005-08-22

    A superconducting radio-frequency photo electron injector (SRF gun) is currently under construction by a collaboration of BESSY, DESY, FZR and MBI. The project aims at the design and setup of a CW SRF gun including a diagnostics beamline for the ELBE FEL and to address R&D issues on low emittance injectors for future light sources such as the BESSY FEL. Of critical importance for the injector performance is the control of the electron beam parameters. For this reason a compact diagnostics beamline is under development serving a multitude of operation settings ranging from low-charge (77pC), low-emittance (1 mm mrad) mode to high-charge (2.5nC) operation of the gun. For these operation modes beam dynamics simulations are resulting in boundary conditions for the beam instrumentation. Proven and mature technology is projected wherever possible, for example for current and beam position monitoring. The layout of the beam profile and emittance measurement systems is described. For the bunch length, which varies between 5 ps and 50 ps, two schemes using electro-optical sampling and Cherenkov radiation are detailed. The beam energy and energy spread is measured with a 180-degree spectrometer.

  18. Behaviour and Modelling of Self-piercing Screw and Self-piercing Rivet Connections: An Experimental and Numerical Investigation

    OpenAIRE

    Sønstabø, Johan Kolstø; Holmstrøm, Petter Henrik

    2013-01-01

    Accurate and reliable models of connections are essential for the design of aluminium parts in cars. Today, there exist a few models customized for self-piercing rivets (SPR), but none for self-piercing screws (SPS). This thesis presents an experimental and numerical study on the behaviour of SPR and SPS connections for different loading situations. For the rolled base material, AA6016 in the T4 condition, uniaxial tension, plane strain tension and in-plane single shear tests were performe...

  19. 8mm三次谐波潘尼管大回旋电子枪设计%Design of large-orbit electron gun for 8 mm third-harmonic peniotron

    Institute of Scientific and Technical Information of China (English)

    武新慧; 李家胤; 赵晓云; 胡标; 李天明

    2012-01-01

    根据现有磁体条件和工艺设计了一过渡区较长的倒向磁场系统,其主磁场为0.396 T,反向磁场为-0.033 T,并给出了一种实用8 mm三次谐波潘尼管电子枪的设计结果.该大回旋电子枪工作在43.5kV,1.45A下,阴极可置于轴向磁场幅值渐减区域.该结构电子枪不追求在通过反转点之前形成薄的环形电子束,不利用突变倒向磁场,不需要刻意控制磁力线与电子注包络走向的一致性,显著降低了调试的难度和要求.最终优化所得电子注的纵向速度零散为4.78%,偏心率为7.18%,速度比高达2.2,而速度比的零散仅为4.88%,满足三次谐波潘尼管的要求.经大信号模拟计算,在该电子枪驱动下,潘尼管器件功率可达31.9 kW,效率高达49.4%,总体参量仍具有吸引力且建立在可实现的电子光学系统基础上.%According to current magnetic and processing conditions, a gradually-changing reversal magnetic system and a practical 8 mm third-harmonic peniotron electron gun are designed. This large-orbit electron gun is designed under the operating voltage of 43. 5 kV, and operating current of 1. 45 A, and its cathode can be located in the axial magnetic field where its magnitude decreases gradually. It does not demand the consistency between the field lines and the contour of the beam trajectories, which reduces the design requirements and difficulty greatly. After optimization, an axis-encircling electron beam with an axial velocity spread of 4. 78% , a guiding center deviation ratio of 7. 18% and a velocity ratio of 2. 2 is obtained, which satisfies the requirements of the third-harmonic peniotron. The large-signal simulation shows that, driven by the electron gun, the peniotron can achieve an output power of 31. 9 kW with the efficiency up to 49. 4%. This is an attractive result in laboratory platform.

  20. 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…

  1. 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…

  2. Electron-gun Evaporation of Cu and In thin films as Precursors for CuInSe{sub 2} Formation; Evaporacion mediante Canon de Electrones de Laminas Delgadas de Cu e In como Precursores para la Obtencion de CuInSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, R.; Guillen, C.

    2001-07-01

    In the present investigation CuInSe{sub 2} is obtained in two stages: sequential evaporation of Cu and In using an electron gun evaporator on substrates up to 30 x 30 cm''2, and a posterior selenization of the deposited films. The study is mainly focused on the first stage, in where the control of the different evaporation parameters of the metal precursors is essential. Electrical measurements are carried out, and also the topography and the thickness are determined with the object of studying the properties and homogeneity of the thin films. (Author) 19 refs.

  3. Emittance studies at the Los Alamos national laboratory free electron laser

    Science.gov (United States)

    Carlsten, B. E.; Feldman, D. W.; Lumpkin, A. H.; Sollid, J. E.; Stein, W. E.; Warren, R. W.

    1988-10-01

    Recent emittance studies at the Los Alamos FEL have indicated several areas of concern in the linac and beamline feeding the wiggler. These studies included both experimental measurements and computer simulations. The beamline starts with a 5 A micropulse from the thermionic cathode in the gun. After bunching by velocity modulation and acceleration to 20 MeV in a 1300 MHz standing wave accelerator, the beam current is roughly 250 A. Final bunching to 800 A is performed in the nonisochronous bend that rotates the electrons onto the axis of the wiggler and the optical cavity. Four emittance growth mechanisms of special importance have been studied. First, a rapid growth of the electron beam's emittance immediately after the spherical gridded Pierce gun resulted, in part, from the long time required for our pulsing electronics to ramp the grid voltage up at the start and down at the end of the pulse, which created a pulse with a cosine-like current distribution as a function of time. The growth was compounded by the extremely small radial beam size (almost a waist) leaving the gun. In addition, we saw evidence of electrostatic charging of the insulators in the gun, reducing the quality of the electron beam further. Second the action of the solenoidal focusing fields in the low-voltage bunching region was studied, and criteria for a minimum emittance growth were established. Third, maximum misalignment angles and displacements for various elements of the beamline were calculated for the desired low emittance growth. Finally, emittance growth in the horizontal dimensions through the nonisochronous bend caused by varying energy depression on the particles due to longitudinal wake fields was both calculated and observed. In addition, we measured energy depressions caused by the wake fields generated by various other elements in the beamline. Strategies were developed to relieve the magnitude of these wake-field effects.

  4. LCLS Gun Solenoid Design Considerations

    Energy Technology Data Exchange (ETDEWEB)

    Schmerge, John

    2010-12-10

    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.

  5. 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.

  6. The progress of funnelling gun high voltage condition and beam test

    Energy Technology Data Exchange (ETDEWEB)

    Wang, E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ben-Zvi, I. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Lambiase, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meng, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rahman, O. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pikin, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rao, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sheehy, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Skaritka, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pietz, J. [Transfer Engineering and Manufacturing, Inc., Fremont, CA (United States); Ackeret, M. [Transfer Engineering and Manufacturing, Inc., Fremont, CA (United States); Yeckel, C. [Thompson, Stangenes Industries, Palo Alto, CA (United States); Miller, R. [Thompson, Stangenes Industries, Palo Alto, CA (United States); Dobrin, E. [Thompson, Stangenes Industries, Palo Alto, CA (United States); Thompson, K. [Thompson, Stangenes Industries, Palo Alto, CA (United States)

    2015-05-03

    A prototype of a high average current polarized electron funneling gun as an eRHIC injector has been built at BNL. The gun was assembled and tested at Stangenes Incorporated. Two beams were generated from two GaAs photocathodes and combined by a switched combiner field. We observed the combined beams on a YAG crystal and measured the photocurrent by a Faraday cup. The gun has been shipped to Stony Brook University and is being tested there. In this paper we will describe the major components of the gun and recent beam test results. High voltage conditioning is discussed as well.

  7. Studies on Some Aspects of Propellants for Improving the Performance of Tank Guns

    Directory of Open Access Journals (Sweden)

    K. P. Rao

    1987-01-01

    Full Text Available The main criterion, in the design of propellant charge for a tank gun, is to achieve the highest possible muzzle velocity for fin stabilized armour piercing dicarding sabot (FSAPDS projectiles. This ensures penetration through the toughest armour plates by the kinetic energy of the projectile. One of the solutions, is to increase the force constant of the propellant. Higher force constant from conventional double and triple base propellant compositions lead to prohibitive linear rates of burning coefficients. ERDL has developed a high energy propellant based on RDX, with very high force constant and low linear rate of burning coefficient. The objective of the present paper is to discuss various aspects of the interior ballistics of the three types of propellants in question in 105 mm tank gun with FSAPDS ammunition. The study shows that only the solution with RDX base propellant is feasible for an increase of three per cent in muzzle velocity.

  8. 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.

  9. 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.

  10. 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

  11. Gun shows and gun violence: fatally flawed study yields misleading results.

    Science.gov (United States)

    Wintemute, Garen J; Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A

    2010-10-01

    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.

  12. Plasma-filled diode based on the coaxial gun.

    Science.gov (United States)

    Zherlitsyn, A A; Kovalchuk, B M; Pedin, N N

    2012-10-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  13. Plasma-filled diode based on the coaxial gun

    Energy Technology Data Exchange (ETDEWEB)

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N. [Institute of High Current Electronics, 2/3 Academichesky Avenue, 634055 Tomsk (Russian Federation)

    2012-10-15

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of {>=}1 MeV at the current of Almost-Equal-To 100 kA was obtained in the experiments with a plasma-filled diode. The energy of Almost-Equal-To 5 kJ with the peak power of {>=}100 GW dissipated in the diode.

  14. Plasma-filled diode based on the coaxial gun

    Science.gov (United States)

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N.

    2012-10-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  15. 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.

  16. Guns as a Symbol of American Individualism

    Institute of Scientific and Technical Information of China (English)

    许丹

    2011-01-01

    Due to continuous gun violence, Americans' crazy love for guns has always been attacked home and abroad. Americans' passion for guns derives from individualism through the development of American history. They consider guns as a means to guarantee independence and freedom, and therefore as a symbol of American individualism.

  17. Calculating effective gun control policies

    CERN Document Server

    Wodarz, Dominik

    2013-01-01

    Following recent shootings in the USA, a debate has erupted, one side favoring stricter gun control, the other promoting protection through more weapons. We provide a scientific foundation to inform this debate, based on population dynamic models that quantify the dependence of firearm-related death rates of people on gun policies. We assume a shooter attacking a single individual or a crowd. Two strategies can minimize deaths in the model, depending on parameters: either a ban of private firearms possession, or a policy allowing the general population to carry guns. In particular, the outcome depends on the fraction of offenders that illegally possess a gun, on the degree of protection provided by gun ownership, and on the fraction of the population who take up their right to own a gun and carry it with them when attacked, parameters that can be estimated from statistical data. With the measured parameters, the model suggests that if the gun law is enforced at a level similar to that in the United Kingdom, g...

  18. 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

  19. 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 be

  20. Emittance Measurements of the SSRL Gun Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Michael; Clendenin, James; Fisher, Alan; Miller, Roger; Palmer, Dennis; Park, Sam; Schmerge, John; Weaver, Jim; Wiedemann, Helmut; Winick, Herman; Yeremian, Dian; /SLAC; Meyerhofer, David; Reis, David; /Rochester U.

    2011-09-01

    A photocathode RF gun test stand is under construction in the injector vault of the Stanford Synchrotron Radiation Laboratory at SLAC. The goal of this facility is to produce an electron beam with a normalized emittance of 1-3[mm-mr], a longitudinal bunch duration of the order of 10[ps] FWHM and approximately 1[nC] of charge per bunch. The beam will be generated from a laser driven copper photocathode RF gun 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. The emittance of the electron beam will be measured through the use of quadrupole scans with phosphor screens and also a wire scanner. The details of the experimental setup will be discussed, and first measurements will be presented and compared with results from PARMELA simulations.

  1. The Development of the Linac Coherent Light Source RF Gun

    CERN Document Server

    Dowell, David H; Lewandowski, James; Limborg-Deprey, Cecile; Li, Zenghai; Schmerge, John; Vlieks, Arnold; Wang, Juwen; Xiao, Liling

    2015-01-01

    The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL). In addition to many other stringent requirements, the LCLS XFEL requires extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new 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. This paper describes the analysis and design improvements of the BNL/SLAC/UCLA s-band gun leading to achievement of the LCLS performance goals.

  2. Comparative analysis of the tardigrade feeding apparatus: adaptive convergence and evolutionary pattern of the piercing stylet system

    Directory of Open Access Journals (Sweden)

    Roberto Guidetti

    2013-03-01

    Full Text Available A thorough analysis of the cuticular parts of tardigrade feeding apparatuses was performed in order to provide a more complete understanding of their evolution and their potential homologies with other animal phyla (e.g. Cycloneuralia and Arthropoda. The buccal- pharyngeal apparatuses of eight species belonging to both Eutardigrada and Heterotardigrada were studied using light and scanning electron microscopy. This study supports and completes a previous study on the relationships between form and function in the buccalpharyngeal apparatus of eutardigrades. The common sclerified structures of the tardigrade buccal-pharyngeal apparatus are: a buccal ring connected to a straight buccal tube, a buccal crown, longitudinal thickenings within the pharynx, and a stylet system composed of piercing stylets within stylet coats, and stylet supports. Specifically, heterotardigrades (Echiniscoidea have a narrow buccal tube; long piercing stylets, each with a longitudinal groove, that cross one another before exiting the mouth; pharyngeal bars and secondary longitudinal thickenings within the pharynx. In contrast, eutardigrades have stylets which are shorter than the buccal tube; Parachela have pharyngeal apophyses and placoids within the pharynx, while Apochela lack a buccal crown and cuticular thickenings within the pharynx, the buccal tube is very wide, and the short stylets are associated with triangular-shaped stylet supports. In both classes, when the piercing stylet tips emerge from the mouth to pierce food, the buccal tube opening is almost completely obstructed, which may hinder food uptake. In heterotardigrades, the crossing of the piercing stylets may further decrease food uptake, however this disadvantage may have been reduced in echiniscids by the evolution of a long buccal tube and long stylets able to run more parallel to the buccal tube. In contrast, eutardigrades evolved different strategies. In the order Apochela and in several

  3. Tattoos, piercing, and sexual behaviors in young adults.

    Science.gov (United States)

    Nowosielski, Krzysztof; Sipiński, Adam; Kuczerawy, Ilona; Kozłowska-Rup, Danuta; Skrzypulec-Plinta, Violetta

    2012-09-01

    Body piercing and tattooing are accepted by a growing number of teenagers and young adults as a way of self-expressing. Some authors suggest association between body piercings/tattoos and early sexual initiation, higher number of sexual partners, or risky sexual behaviors. The aim of the study was to evaluate sexual behaviors among young adults with body modifications (BMs)--tattoos and piercings. One hundred twenty young healthy adults, ages between 20 and 35, were included in the population study. The study group was divided into three subgroups: controls (N = 60), adults with tattoos (N = 28), and adults with piercings (N = 32). The research instrument was a self-prepared questionnaire containing 59 questions assessing socioepidemiological parameters, sexual behaviors, incidents of sexual harassment in the past, and self-attractiveness evaluation, as well as questions concerning tattoos and piercings. Socioepidemiological variables and sexual behaviors were compared between subgroups. To assess and describe the correlation between having BM--tattoos and piercing--and sexual behaviors in the population of young adults by using the logistic regression model. Adults with BMs have had their first intercourse statistically earlier and were more sexually active compared with controls. There were no statically significant differences in sexual orientation, sexual preferences, engaging in risky sexual behaviors, frequency of masturbation, and history of sexual abuse between the groups. In contrast, the frequency of sexual intercourses was statistically higher and oral sex was more likely to be a dominant sexual activity in adults with BM compared with controls. The multivariate logistic model revealed that adults with BM were four times less likely to participate in religious practices and twice more likely to have early sexual initiation. Having BM is associated with early sexual initiation and more liberal attitudes toward sexual behaviors but not with engaging in

  4. 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.

  5. (Pulsed electron beam precharger)

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1990-01-01

    This report discusses the following topics on electron beam guns: Precharger Modification; Installation of Charge vs. Radius Apparatus; High Concentration Aerosol Generation; and Data Acquisition and Analysis System.

  6. The strength analysis of the wave piercing buoy

    Science.gov (United States)

    Jiang, Dong; Li, Wenhua; Chen, Xinyang; Chen, Haiquan

    2017-04-01

    The wave piercing buoy in this paper is different with the traditional cylindrical buoy, it is made by ultra-high molecular weight polyethylene (UHMWPE) and has six middle pontoons. In order to guarantee the stability of the buoy structure, it is necessary to carry out the strength analysis. This paper use the ANSYS software to carry on the simulation analysis to the buoy, and the result of it is compare with the actual operation, therefore ensure the strength of the wave piercing buoy meet the related requirements.

  7. Reverse Ballistic Air Gun Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This custom-designed facility houses a suite of three air guns capable of generating accelerations up to 100,000 Gs and velocities up to 2,000 ft/s. In addition to a...

  8. Reverse Ballistic Air Gun Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This custom-designed facility houses a suite of three air guns capable of generating accelerations up to 100,000 Gs and velocities up to 2,000 ft/s. In addition to...

  9. 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.

  10. 78 FR 78808 - Proposed Flood Elevation Determinations for Pierce County, Washington, and Incorporated Areas

    Science.gov (United States)

    2013-12-27

    ... Pierce County, Washington, and Incorporated Areas AGENCY: Federal Emergency Management Agency, DHS... its proposed rule concerning proposed flood elevation determinations for Pierce County, Washington... sources in Pierce County, Washington. On April 16, 2012, FEMA published a proposed rulemaking at 77 FR...

  11. 27 CFR 478.37 - Manufacture, importation and sale of armor piercing ammunition.

    Science.gov (United States)

    2010-04-01

    ... and sale of armor piercing ammunition. 478.37 Section 478.37 Alcohol, Tobacco Products, and Firearms..., importation and sale of armor piercing ammunition. No person shall manufacture or import, and no manufacturer or importer shall sell or deliver, armor piercing ammunition, except: (a) The manufacture or...

  12. 78 FR 4804 - Revision to the Washington State Implementation Plan; Tacoma-Pierce County Nonattainment Area

    Science.gov (United States)

    2013-01-23

    ... AGENCY 40 CFR Part 52 Revision to the Washington State Implementation Plan; Tacoma- Pierce County... (CAA) requirements related to the Tacoma-Pierce County nonattainment area for the 2006 fine particulate... Tacoma-Pierce County Clean Air Task Force, an advisory committee of community leaders, citizen...

  13. 27 CFR 478.92 - How must licensed manufacturers and licensed importers identify firearms, armor piercing...

    Science.gov (United States)

    2010-04-01

    ... manufacturers and licensed importers identify firearms, armor piercing ammunition, and large capacity ammunition..., armor piercing ammunition, and large capacity ammunition feeding devices? (a)(1) Firearms. You, as a... (bases). (b) Armor piercing ammunition—(1) Marking of ammunition. Each licensed manufacturer or licensed...

  14. 75 FR 14467 - Notice of Inventory Completion: Pierce College District, Lakewood, WA, and Thomas Burke Memorial...

    Science.gov (United States)

    2010-03-25

    ... National Park Service Notice of Inventory Completion: Pierce College District, Lakewood, WA, and Thomas... in the control of the Pierce College District, Lakewood, WA, and in the physical custody of the... human remains were most likely removed from Gig Harbor, Pierce County, WA. This notice is published as...

  15. 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.

  16. 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.

  17. Study program for design improvements of the X-3060 klystron. Phase 3: Electron gun fabrication and beam analyzer evaluation. Phase 4: Klystron prototype fabrication and testing

    Science.gov (United States)

    Goldfinger, A.

    1981-01-01

    A full scale model was produced to verify suggested design changes. Through beam analyzer study, the correct electron beam diameter and cross sectional profile were established in conjunction with the desired confining magnetic field. Comparative data on the performance of the X-3060 klystron, design predictions for the improved klystron, and performance data taken during acceptance testing of the prototype VKS-8274 JPL are presented.

  18. A novel surface-repairing technique for gun bore

    Institute of Scientific and Technical Information of China (English)

    SU Bing; YU Xu-dong; WU Bin; WANG Cheng-tao

    2005-01-01

    A novel surface-repairing technique for gun bore was investigated, which was combined with the merits such as anti-erosion wear, damage-repairing, and etc. It was accomplished by adhering a special rare earth nanocom posite evenly to the micro-surface of gun bore. The effectiveness of this technique was approved by the target-firing using a domestic automatic rifle with chromium-coated bore. Its characteristics were discussed based on the surface analyses of the rifle bore by secondary ion mass spectrometry(SIMS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.

  19. The Separation of School and State: Pierce Reconsidered

    Science.gov (United States)

    Arons, Stephen

    1976-01-01

    Does the Constitution protect parents' right to pass their values along to their children? Author argues that it does, basing his contention on the language and the history of Pierce v. Society of Sisters, the landmark decision that guaranteed private schools' right to do business. (Editor/RK)

  20. George Pierce Baker's "Principles of Argumentation": "Completely Logical"?

    Science.gov (United States)

    Bordelon, Suzanne

    2006-01-01

    The article contends that previous scholars have misread George Pierce Baker's efforts by focusing primarily on "The Principles of Argumentation" and the role of logic. Baker's view of logic was more complex than scholars have claimed. He challenged traditional concepts of formal logic, highlighting only those aspects that would help students…

  1. Pierce County High School: Excellence Is the Standard

    Science.gov (United States)

    Principal Leadership, 2012

    2012-01-01

    This article features Pierce County High School in rural southeast Georgia whose 965 students, almost half of whom are from economically disadvantaged families, have demonstrated what a focus on student learning can accomplish. In 2004, the school ranked at the bottom of the state in students passing the high school graduation tests, and only 55%…

  2. Scaling properties of Wilson loops pierced by P-vortices

    DEFF Research Database (Denmark)

    Dunn, Patrick; Greensite, Jeffrey Paul

    2012-01-01

    these ratios are plotted versus loop area in physical units, for a range of lattice couplings, it is found that the points fall approximately on a single curve, consistent with scaling. We also find that the ratios are rather insensitive to the point where the minimal area of the loop is pierced by the P-vortex....

  3. Psychosocial Adjustment of College Students with Tattoos and Piercings

    Science.gov (United States)

    Roberti, Jonathan W.; Storch, Eric A.

    2005-01-01

    The purpose of this study was to examine the association between body modification practices and psychosocial adjustment. Participants were 198 undergraduate college students, 129 of whom had I or more piercings (other than in earlobe) or tattoos. Findings showed that individuals with body modifications reported more symptoms of depression and…

  4. A New Keyboard for the Bohlen-Pierce Scale

    CERN Document Server

    Nassar, Antonio

    2011-01-01

    The study of harmonic scales of musical instruments is discussed in all introductory physics texts devoted to the science of sound. In this paper, we present a new piano keyboard to make the so-called Bohlen-Pierce scale more functional and pleasing for composition and performance.

  5. Galois Got his Gun

    CERN Document Server

    Brechenmacher, Frederic

    2011-01-01

    This paper appeals to the figure of \\'Evariste Galois for investigating the gates between mathematics and their "publics." The figure of Galois draws some lines of/within mathematics for/from the outside of mathematics and these lines in turn sketch the silhouette of Galois as a historical figure. The present paper especially investigates the collective categories that have been used in various types of public discourses on Galois's work (e.g. equations, groups, algebra, analysis, France, Germany etc.). In a way, this paper aims at shedding light on the boundaries some individuals drew by getting Galois his gun. It is our aim to highlight the roles of authority some individuals (such as as Picard) took on in regard with the public figure of Galois as well as the roles such authorities assigned to other individuals (such as the mediating role assigned to Jordan as a mediator between Galois's "ideas" and the public). The boundary-works involved by most public references to Galois have underlying them a long-ter...

  6. 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.

  7. Revisiting Pneumatic Nail Gun Trigger Recommendations.

    Science.gov (United States)

    Albers, James; Lowe, Brian; Lipscomb, Hester; Hudock, Stephen; Dement, John; Evanoff, Bradley; Fullen, Mark; Gillen, Matt; Kaskutas, Vicki; Nolan, James; Patterson, Dennis; Platner, James; Pompeii, Lisa; Schoenfisch, Ashley

    2015-03-01

    Use of a pneumatic nail gun with a sequential actuation trigger (SAT) significantly diminishes the risk for acute traumatic injury compared to use of a contact actuation trigger (CAT) nail gun. A theoretically-based increased risk of work-related musculoskeletal disorders from use of a SAT nail gun, relative to CAT, appears unlikely and remains unproven. Based on current knowledge, the use of CAT nail guns cannot be justified as a safe alternative to SAT nail guns. This letter provides a perspective of ergonomists and occupational safety researchers recommending the use of the sequential actuation trigger for all nail gun tasks in the construction industry.

  8. Operation of the superconducting RF photo gun at ELBE

    CERN Document Server

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, Ch; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2012-01-01

    As the first superconducting RF photo-injector (SRF gun) in practical operation, the SRF gun has been successfully connected to the superconducting linac ELBE at Forschungzentrum Dresden-Rossendorf. The injection with this new gun will improve the beam quality for the users of the radiation source. The SRF gun contains a 3½ cell superconducting accelerating cavity with a frequency of 1.3 GHz. The design is for use of normal conducting photocathodes. At present, caesium telluride photocathodes are applied which are illuminated by an ultraviolet laser beam. The kinetic energy of the produced electron beam is 3 MeV which belongs to a peak electric field of 16 MV/m in the cavity. The maximum bunch charge which is obtained and measured in a Faraday cup is about 400 pC (20 μA average current at a repetition rate of 50 kHz). The SRF gun injector is connected to the ELBE accelerator via a dogleg with two 45° deflection magnets. This connection beam line was commissioned in January 2010. A first beam injection into...

  9. Operation of the superconducting RF photo gun at ELBE

    CERN Document Server

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2011-01-01

    As the first superconducting RF photo-injector (SRF gun) in practical operation, the SRF gun has been successfully connected to the superconducting linac ELBE at Forschungzentrum Dresden-Rossendorf. The injection with this new gun will improve the beam quality for the users of the radiation source. The SRF gun contains a 3½ cell superconducting accelerating cavity with a frequency of 1.3 GHz. The design is for use of normal conducting photocathodes. At present, caesium telluride photocathodes are applied which are illuminated by an ultraviolet laser beam. The kinetic energy of the produced electron beam is 3 MeV which belongs to a peak electric field of 16 MV/m in the cavity. The maximum bunch charge which is obtained and measured in a Faraday cup is about 400 pC (20 µA average current at a repetition rate of 50 kHz). The SRF gun injector is connected to the ELBE accelerator via a dogleg with two 45° deflection magnets. This connection beam line was commissioned in January 2010. A first beam injection into...

  10. Rf Gun with High-Current Density Field Emission Cathode

    Energy Technology Data Exchange (ETDEWEB)

    Jay L. Hirshfield

    2005-12-19

    High current-density field emission from an array of carbon nanotubes, with field-emission-transistor control, and with secondary electron channel multiplication in a ceramic facing structure, have been combined in a cold cathode for rf guns and diode guns. Electrodynamic and space-charge flow simulations were conducted to specify the cathode configuration and range of emission current density from the field emission cold cathode. Design of this cathode has been made for installation and testing in an existing S-band 2-1/2 cell rf gun. With emission control and modulation, and with current density in the range of 0.1-1 kA/cm2, this cathode could provide performance and long-life not enjoyed by other currently-available cathodes

  11. Measurement of Ampère-class pulsed electron beams via field emission from carbon-nanotube cathodes in a radiofrequency gun

    Science.gov (United States)

    Mihalcea, D.; Faillace, L.; Hartzell, J.; Panuganti, H.; Boucher, S.; Murokh, A.; Piot, P.; Thangaraj, J. C. T.

    2015-07-01

    Pulsed field emission from cold carbon-nanotube cathodes placed in a radiofrequency resonant cavity was directly measured. The cathodes were located on the backplate of a conventional 1 + /1 2 -cell resonant cavity operating at 1.3-GHz and resulted in the production of bunch train with maximum average current close to 0.7 Ampère. The measured Fowler-Nordheim characteristic, transverse emittance, and pulse duration are presented and, when possible, compared to numerical simulations. The implications of our results to the promise of high-average-current electron sources are briefly discussed.

  12. Just a personal thing? A qualitative account of health behaviours and values associated with body piercing.

    Science.gov (United States)

    Randall, Jason A; Sheffield, David

    2013-03-01

    This study investigates the perceptions of individuals with body piercings in relation to health behaviours and values specifically taking into account piercing location. A qualitative study that employed a series of in-depth, semi-structured individual interviews using thematic analysis to analyse data. Nine individuals with a range of piercings were recruited and semi-structured interviews were carried out in a West Midlands piercing studio. The analysis identified themes relating to the presence of body piercings that included a range of health-related outcomes such as physical appearance, health behaviours, addiction and impressions. A possible relationship between oral piercings and 'crash dieting' was also identified. The results suggest that from the comments made the presence of body piercings is not related to any particular health concern, which is instead comparable to the general population. These results contradict previous studies citing a relationship with high-risk health behaviours. Further large-scale studies examining these findings are warranted.

  13. Patients' perceptions of patient care providers with tattoos and/or body piercings.

    Science.gov (United States)

    Westerfield, Heather V; Stafford, Amy B; Speroni, Karen Gabel; Daniel, Marlon G

    2012-03-01

    This study evaluated patients' perceptions of patient care providers with visible tattoos and/or body piercings. As tattooing and body piercing are increasingly popular, research that informs nursing administrators regarding policies on patient care providers having visible tattoos and body piercings is warranted. A total of 150 hospitalized adult patients compared pictures of male and female patient care providers in uniform with and without tattoos and/or nonearlobe body piercings. Patient care providers with visible tattoos and/or body piercings were not perceived by patients in this study as more caring, confident, reliable, attentive, cooperative, professional, efficient, or approachable than nontattooed or nonpierced providers. Tattooed female providers were perceived as less professional than male providers with similar tattoos. Female providers with piercings were perceived as less confident, professional, efficient, and approachable than nonpierced female providers. Nursing administrators should develop and/or evaluate policies regarding patient care providers with visible tattoos and/or body piercings.

  14. A power ramped pulsed mode laser piercing technique for improved CO 2 laser profile cutting

    Science.gov (United States)

    Tirumala Rao, B.; Ittoop, M. O.; Kukreja, L. M.

    2009-11-01

    Laser piercing is one of the inevitable requirements of laser profile cutting process and it has a direct bearing on the quality of the laser cut profiles. We have developed a novel power ramped pulsed mode (PRPM) laser piercing technique to produce much finer pierced holes and to achieve a better control on the process parameters compared to the existing methodology based on normal pulsed mode (NPM). Experiments were carried out with both PRPM and NPM laser piercing on 1.5-mm-thick mild steel using an in-house developed high-power transverse flow continuous wave (CW)-CO 2 laser. Significant improvements in the spatter, circularity of the pierced hole and reproducibility were achieved through the PRPM technique. We studied, in detail, the dynamics of processes involved in PRPM laser piercing and compared that with those of the NPM piercing.

  15. Description of the plasma diagnostics package (PDP) for the OSS-1 Shuttle mission and JSC plasma chamber test in conjunction with the fast pulse electron gun (FPEG)

    Science.gov (United States)

    Shawhan, S. D.

    1982-01-01

    The objectives, equipment, and techniques for the plasma diagnostics package (PDP) carried by the OSS-1 instrument payload of the STS-4 and scheduled for the Spacelab-2 mission are described. The goals of the first flight were to examine the Orbiter-magnetoplasma interactions by measuring the electric and magnetic field strengths, the ionized particle wakes, and the generated waves. The RMS was employed to lift the unit out of the bay in order to allow characterization of the fields, EM interference, and plasma contamination within 15 m of the Orbiter. The PDP will also be used to examine plasma depletion, chemical reaction rates, waves, and energized plasma produced by firing of the Orbiter thrusters. Operation of the PDP was carried out in the NASA Space Environment Simulation Laboratory test chamber, where the PDP was used to assay the fields, fluxes, wave amplitudes, and particle energy spectra. The PDP instrumentation is also capable of detecting thermal ions, thermal electrons suprathermal particles, VHF/UHF EMI levels, and the S-band field strength.

  16. The corrosion resistance of materials used for the manufacture of ear piercing studs

    Energy Technology Data Exchange (ETDEWEB)

    Correa, O. V.; Saiki, M.; Rogero, S. O.; Costa, I.

    2003-07-01

    Nickel containing alloy shave been widely used as substrates for the manufacture of studs used for ear piercing. Unfortunately, nickel has also been related to the development of allergic contact dermatitis caused by skin sensitization due to Ni''2+ ions. Nickel ions can be leached out into the body fluids due to corrosion reactions. Defect free coatings are very difficult to produce, and therefore nickel free materials should be used as substrates of ear piercing studs, although the commercial alloys used usually contain this element. In this study, the corrosion resistance of two kinds of commercial studs prepared with nickel containing substrates and a titanium laboratory made stud was determined in a culture medium. The corrosion resistance of the studs was investigated by means of potentiodynamic polarization tests and electrochemical impedance spectroscopy as a function of immersion time in the culture medium. The elements that leached out into the medium due to corrosion reactions were analyzed by instrumental neutron activation analysis. The surfaces of the commercial gold-coated studs were examined by scanning electron microscopy and analyzed by energy dispersive spectroscopy, both before and after exposure to the culture medium. The cytotoxicity of the tested studs was also determined in the culture medium. (Author) 10 refs.

  17. Hydrogen Embrittlement of Gun Steel

    Science.gov (United States)

    1987-11-01

    8217s HY80 and HY130 steels were checked for the critical hydrogen concentrations which were determined to be 6 ppm for HY8O steel 8 and 3 ppm for HY130...JOTC FILE COPY AD-A188 972 AD 1 TECHNICAL REPORT ARCCB-TR-87030 HYDROGEN EMBRITTLEMENT OF GUN STEEL F’ GERALD L. SPFNCER DTIC DEC 1 5 1987 NOVEMBER...PtEtIOC COVERED HYDROGEN EMBRITTLEHENT OF GUN STEEL Final OG EOTNME 6. PERFORMINGORO EOTNME 7. A*JTNOR(s) S. CONTRACT OR GRANT NUMBER(&) Gerald L

  18. Advances in light-gas gun technology

    Science.gov (United States)

    Cowan, P. L.; Murphy, J. R.

    1968-01-01

    Constant-area accelerator used with light-gas guns increases the velocity of accelerating projectiles. A disposable accelerator on the muzzle of the gun uses the energy and momentum of a primary projectile, launched by the gun, to achieve high velocities of a light secondary projectile accelerated from rest in the accelerator.

  19. Liquid Propellants for Advanced Gun Ammunitions

    Directory of Open Access Journals (Sweden)

    K. P. Rao

    1987-01-01

    Full Text Available With constant improvements, the conventional solid propellants for guns have almost reached their limit in performance. Liquid gun propellants are promising new comers capable of surpassing these performance limits and have numerous advantages over solid propellants. A method has been worked out to predict the internal ballistics of a liquid propellant gun and illustrated in a typical application.

  20. Triple inverter pierce oscillator circuit suitable for CMOS

    Science.gov (United States)

    Wessendorf; Kurt O.

    2007-02-27

    An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

  1. The impairment of Presidents Pierce and Coolidge after traumatic bereavement.

    Science.gov (United States)

    Davidson, Jonathan R T; Connor, Kathryn M

    2008-01-01

    The impact of bereavement in heads of government has been little studied. Two US presidents lost their teenaged sons in a traumatic manner, leaving them profoundly affected as they struggled to serve in office. We describe the bereavements of Presidents Franklin Pierce and Calvin Coolidge, using biographical and source material. Pierce and Coolidge were adversely affected by their bereavements, which almost certainly rendered them less effective in the discharge of their duties. The loss of their sons had a devastating effect on both men and deprived their presidential service of significant personal meaning. Lincoln's resilience in similar circumstances offers a contrasting perspective, however. We conclude that the psychiatric consequences of losing a child can adversely affect heads of government, may cause clinically significant distress, altered behavior, and reduced ability to provide effective leadership.

  2. The Development of Piezo-Driven Tools for Cellular Piercing

    Directory of Open Access Journals (Sweden)

    Changhai Ru

    2016-10-01

    Full Text Available Conventionally, intracytoplasmic sperm injection (ICSI in the mouse is conducted with piezo-drills that use a droplet of mercury for damping. The use of mercury causes concerns of toxicity and contamination. Although Fluorinert can be used as a substitute for mercury to reduce piezo-drill’s lateral vibration, the damping effect is not as satisfactory as mercury. In this work, a modified piezo-drill without using mercury was developed for the cellular piercing of mouse oocytes. Experimentally, appropriate parameters of driving voltage and frequency were obtained for the penetration of the zona pellucida of mouse oocytes. Furthermore, the lateral vibration of the injection pipette is lower than 1 μm in deionized water, which is not observable at 400 magnificence. With the piezo-drill without using mercury, the system performs the cellular piercing of mouse oocytes with a maximum cleavage rate of 94.7% (n = 117.

  3. Pierce - University of Georgia | Division of Cancer Prevention

    Science.gov (United States)

    Principal Investigator: J. Michael Pierce, PhDInstitution: University of Georgia, Athens, GA Our project, Discovery and Development of Cancer Glycomarkers, is a joint collaboration between our laboratories at the CCRC, which include Karen Abbott, Lance Wells, Kevin Dobbin, and Mike Tiemeyer, those at TGen, in Phoenix, AZ, Daniel Von Hoff, Haiyong Han, and Mike Demeure, and Caerus Discovery in Manassas, VA, which includes Cohava Gelber and S?ren Mogelsvang. |

  4. Fisher Pierce products for improving distribution system reliability

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The challenges facing the electric power utility today in the 1990s has changed significantly from those of even 10 years ago. The proliferation of automation and the personnel computer have heightened the requirements and demands put on the electric distribution system. Today`s customers, fighting to compete in a world market, demand quality, uninterrupted power service. Privatization and the concept of unregulated competition require utilities to streamline to minimize system support costs and optimize power delivery efficiency. Fisher Pierce, serving the electric utility industry for over 50 years, offers a line of products to assist utilities in meeting these challenges. The Fisher Pierce Family of products provide tools for the electric utility to exceed customer service demands. A full line of fault indicating devices are offered to expedite system power restoration both locally and in conjunction with SCADA systems. Fisher Pierce is the largest supplier of roadway lighting controls, manufacturing on a 6 million dollar automated line assuring the highest quality in the world. The distribution system capacitor control line offers intelligent local or radio linked switching control to maintain system voltage and Var levels for quality and cost efficient power delivery under varying customer loads. Additional products, designed to authenticate revenue metering calibration and verify on sight metering service wiring, help optimize the profitability of the utility assuring continuous system service improvements for their customers.

  5. Commissioning Results of the 2nd 3.5 Cell SRF Gun for ELBE

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A [HZDR, Dresden, Germany; Freitag, M [HZDR, Dresden, Germany; Murcek, Petr [HZDR, Dresden, Germany; Teichert, Jochen [HZDR, Dresden, Germany; Vennekate, H [HZDR, Dresden, Germany; Xiang, R [HZDR, Dresden, Germany; Ciovati, Gianluigi [JLAB; Kneisel, Peter K. [JLAB; Turlington, Larry D, [JLAB

    2014-12-01

    As in 2007 the first 3.5 cell superconducting radio frequency (SRF) gun was taken into operation, it turned out that the specified performance has not been achieved. However, to demonstrate the full potential of this new type of electron source, a second and slightly modified SRF gun II was built in collaboration with Thomas Jefferson National Accelerator Facility (TJNAF). We will report on commissioning and first results of the new gun, which includes in particular the characterization of the most important RF properties as well as their comparison with previous vertical test results.

  6. Pulsed Mode Operation and Longitudinal Parameter Measurement of the Rossendorf SRF Gun

    CERN Document Server

    Teichert, J; Buettig, H; Justus, M; Lehnert, U; Michel, P; Schamlott, A; Schneider, Ch; Schurig, R; Xiang, R; Klemz, G; Kamps, T; Rudolph, J; Schenk, M; Will, I

    2011-01-01

    The Rossendorf SRF gun with a 3½ cell cavity has been operated since 2007. It has produced CW beam with the electron energy of 3 MeV and the average current up to 16 μA. The electron beam of the gun has been successfully injected into the ELBE superconducting linac since 2010. The Nb cavity has shown constant quality during the operation and for the Cs2Te photocathode life time of months could be obtained. Recently the gun started to run in the pulsed mode with higher gradient. The longitudinal Parameters have been measured in this mode. The dark current arose from the high gradient is studied. The main field emission source has been found to be the half cell. In this paper the new status of the SRF gun will be presented, and the latest results of the beam experiments will be discussed.

  7. Development of an ultrashort table-top electron and x-ray source pumped by laser

    Science.gov (United States)

    Girardeau-Montaut, Jean-Pierre; Kiraly, Bela; Girardeau-Montaut, Claire; Leboutet, Hubert

    1999-09-01

    We report on the design of the CIBER-X source which is a new laser driven table-top ultrashort electron and x-ray source. X-ray pulses are produced by a three-step process which consists of the electron pulse production from a thin metallic photocathode illuminated by picosecond 213 nm laser pulses with 16 ps duration. The electrons are accelerated in the diode by a cw electric field of 11 MV/m, and the photoinjector produces a single 70 - 100 keV electron pulse of approximately 0,5 nC and approximately 20 A peak current at a repetition rate of 10 Hz. The gun is a standard Pierce diode electrode type, the electrons leaving the diode through a hole made in the anode. The electrons are then transported along a path approximately 20 cm long, and are focused by two magnetic fields produced by electromagnetic coils. Finally, the x-rays are produced by the impact of electrons on a massive target of Tm. Simulations of geometrical and energetic characteristics of the complete source were done previously with assistance of the code PIXEL1. Finally, experimental performances of electron and x-ray bursts are discussed.

  8. Design of a High Speed Planing Hull with a Cambered Step and Surface Piercing Hydrofoils

    Science.gov (United States)

    2014-06-01

    Design of a High Speed Planing Hull with a Cambered Step and Surface Piercing Hydrofoils by Leon Alexander Faison Bachelor of Science in...Speed Planing Hull with a Cambered Step and Surface Piercing Hydrofoils 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...cambered step and stern, surface piercing hydrofoils , commonly known as a Dynaplane hull. This configuration combines the drag reduction benefits of a

  9. BILATERAL PERICHONDRITIS OF PINNA FOLLOWING PIERCING OF HELIX – A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Rajamani

    2014-01-01

    Full Text Available Piercing of Helix of pinna is a social custom of certain communities in Northern Tamil Nadu. Such a “high helical” piercing is well known to cause Perichondritis of Pinna. Most of the times such a Perichondritis is unilateral. Here we present a case of Bilateral Perichondritis of pinna, following ear piercing, first time from India subcontinent. We also highlight some practical points on management of such cases.

  10. Projectile Balloting Attributable to Gun Tube Curvature

    Directory of Open Access Journals (Sweden)

    Michael M. Chen

    2010-01-01

    Full Text Available Transverse motion of a projectile during launch is detrimental to firing accuracy, structural integrity, and/or on-board electronics performance of the projectile. One manifest contributing factor to the undesired motion is imperfect bore centerline straightness. This paper starts with the presentation of a deterministic barrel model that possesses both vertical and lateral deviations from centerline in accordance with measurement data, followed by a novel approach to simulating comprehensive barrel centerline variations for the investigation of projectile balloting^1 motions. A modern projectile was adopted for this study. In-bore projectile responses at various locations of the projectile while traveling through the simulated gun tubes were obtained. The balloting was evaluated in both time and frequency domains. Some statistical quantities and the significance were outlined.

  11. A gasdynamic gun driven by gaseous detonation

    Science.gov (United States)

    Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

    2016-01-01

    A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels.

  12. Fibre laser piercing of mild steel: the effects of power intensity, gas type and pressure

    OpenAIRE

    Hashemzadeh, M.; Powell, J.; Voisey, K.T.

    2014-01-01

    Laser piercing is used to generate a starting point for laser cutting. The pierced hole is normally larger than the kerf width, which means that it cannot lie on the cut line. An experimental program investigating the piercing process as a function of laser and assist gas parameters is presented. An Nd:YAG fibre laser with a maximum power of 2 kW was used in continuous wave mode to pierce holes in 2 mm thick mild steel. Oxygen and nitrogen were used as assist gases, with pressures ranging fro...

  13. Fibre laser piercing of mild steel - The effects of power intensity, gas type and pressure

    Science.gov (United States)

    Hashemzadeh, M.; Powell, J.; Voisey, K. T.

    2014-04-01

    Laser piercing is used to generate a starting point for laser cutting. The pierced hole is normally larger than the kerf width, which means that it cannot lie on the cut line. An experimental programme investigating the piercing process as a function of laser and assist gas parameters is presented. An Nd:YAG fibre laser with a maximum power of 2 kW was used in continuous wave mode to pierce holes in 2 mm thick mild steel. Oxygen and nitrogen were used as assist gases, with pressures ranging from 0.3 to 12 bar. The sizes, geometries and piercing time of the holes produced have been analysed. The pierced hole size decreases with increasing gas pressure and increasing laser power. Oxygen assist gas produced larger diameter holes than nitrogen. A new technique is presented which produces pierced holes no larger than the kerf with and would allow the pierced hole to lie on the cut line of the finished product - allowing better material usage. This uses an inclined jet of nitrogen when piercing prior to oxygen assisted cutting.

  14. Effects of a gun dealer's change in sales practices on the supply of guns to criminals.

    Science.gov (United States)

    Webster, Daniel W; Vernick, Jon S; Bulzacchelli, Maria T

    2006-09-01

    Licensed gun dealers are a major conduit for gun trafficking. Prior to May 1999, a single gun store sold more than half of the guns recovered from criminals in Milwaukee, WI, shortly following retail sale. On May 10, 1999, the store stopped selling small, inexpensive handguns popular with criminals, often called "Saturday night specials." The purpose of this study was to estimate the effect of this gun store's changed sales practices on criminals' acquisition of new guns. We used an interrupted time-series design with comparisons to test for changes in the number of guns that police recovered from criminals within a year of retail sale following the gun dealer's new sales policy. The dealer's changed sales policy was associated with a 96% decrease in recently sold, small, inexpensive handguns use in crime in Milwaukee, a 73% decrease in crime guns recently sold by this dealer, and a 44% decrease in the flow of all new, trafficked guns to criminals in Milwaukee. The findings demonstrate the substantial impact that a single gun store's sales practices can have on the supply of new guns to criminals. Proposed anti-gun-trafficking efforts in other cities could benefit from targeting problem retail outlets.

  15. BXERL photo-injector based on a 217 MHz normal conducting RF gun

    Institute of Scientific and Technical Information of China (English)

    LIU Sheng-Guang; HUANG Tong-Ming; XU Jin-Qiang

    2011-01-01

    The Beijing X-ray Energy Recovery Linac(BXERL)test facility is proposed in Institute of High Physics(IHEP).In this proposal,the main linac requires the injector to provide an electron beam with 5 MeV energy and 10 mA average current.An injector based on DC gun technology is the first candidate electron source for BXERL.However,the field emission in the DC gun cavity makes it much more difficult to increase the high voltage to more than 500 kV.Another technology based on a 217 MHz normal conducting RF gun is proposed as the backup injector for this test facility.We have designed this RF gun with 2D SUPERFISH code and 3D MICROWAVE STUDIO code.In this paper,we present the optimized design of the gun cavity,the gun RF parameters and the set-up of the whole injector system.The detailed beam dynamics have been done and the simulation results show that the injector can generate electron bunches with RMS normalizedemittance 1.0 πmm.mrad,bunch length 0.77 mm,beam energy 5.0 MeV and energy spread 0.60%.

  16. Photocathode guns for single pass X-ray FELs

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, D.T.

    1997-10-01

    The present state of the art in photoinjector designs will be presented in this review. The authors discuss both proposed and operational photoinjectors with operating frequencies from L-band (1.424 GHz) to X-band (11.424 GHz). Also a novel pulsed DC gun will be presented. All the RF photoinjector discussed here use an emittance compensation scheme to align the different slices of the electron beam to decrease the beams normalized rms emittance.

  17. A two-Frequency RF Photocathode Gun

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, D.H. E-mail: dowell@slac.stanford.edu; Ferrario, M.; Kimura, T.; Lewellen, J.; Limborg, C.; Raimondi, P.; Schmerge, J.F.; Serafini, L.; Smith, T.; Young, L

    2004-08-01

    In this paper we resurrect an idea originally proposed by Serafini (Nucl. Instr. and Meth. A 318 (1992) 301) in 1992 for an RF photocathode gun capable of operating simultaneously at the fundamental frequency and a higher frequency harmonic. Driving the gun at two frequencies with the proper field ratio and relative phase produces a beam with essentially no RF emittance and a linear longitudinal phase space distribution. Such a gun allows a completely new range of operating parameters for controlling space charge emittance growth. In addition, the linear longitudinal phase space distribution aids in bunch compression. This paper will compare results of simulations for the two-frequency gun with the standard RF gun and the unique properties of the two-frequency gun will be discussed.

  18. A Two-Frequency RF Photocathode Gun

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, D.

    2004-11-05

    In this paper we resurrect an idea originally proposed by Serafini[1] in 1992 for an RF photocathode gun capable of operating simultaneously at the fundamental frequency and a higher frequency harmonic. Driving the gun at two frequencies with the proper field ratio and relative phase produces a beam with essentially no rf emittance and a linear longitudinal phase space distribution. Such a gun allows a completely new range of operating parameters for controlling space charge emittance growth. In addition, the linear longitudinal phase space distribution aids in bunch compression. This paper will compare results of simulations for the two-frequency gun with the standard rf gun, and the unique properties of the two-frequency gun will be discussed.

  19. 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

    ... Guns and Toy Guns Not Intended for Use With Caps AGENCY: Consumer Product Safety Commission. ACTION... use with toy guns and toy guns not intended for use with caps, which were included in the regulations... revoke our existing banning regulations pertaining to caps intended for use with toy guns and toy...

  20. 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

    ... Guns and Toy Guns Not Intended for Use With Caps AGENCY: Consumer Product Safety Commission. ACTION...-producing toys. Existing CPSC regulations pertaining to caps intended for use with toy guns refer to... intended for use with toy guns and toy guns not intended for use with caps. The final rule is...

  1. Experimental Characterization of Supercavitating Finds Piercing a Ventilated Supercavity

    Science.gov (United States)

    2013-08-05

    1.1 Cavitation 1 1.2 Supercavitation 3 1.3 Supercavitating Hydrofoils 8 1.4 Surface Piercing Hydrofoils 13 1.5 Hydrodynamic Forces 14 1.6 Project...Cavitation on Traditional and Supercavitating Hydrofoil Sections, Adapted from (Auslaender, 1962) 9 1.5 Leading Edge Vibration on a Supercavitating Fin with a...for a Flat Plate Hydrofoil vs. Angle of Attack and Cavitation Number using Wu’s Free Streamline Theory (Wu, 1955). 21 2.3 Estimated Lift and Drag for

  2. Edge state and crisis in the Pierce diode

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Pablo R.; Rempel, Erico L. [Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), CTA/ITA/IEFM, Sao Jose dos Campos-SP 12228-900 (Brazil); Barroso, Joaquim J. [National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P. O. Box 515, Sao Jose dos Campos-SP 12227-010 (Brazil); Chian, Abraham C.-L. [National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P. O. Box 515, Sao Jose dos Campos-SP 12227-010 (Brazil); Observatoire de Paris, LESIA, CNRS, 92195 Meudon (France)

    2012-09-15

    We study the chaotic dynamics of the Pierce diode, a simple spatially extended system for collisionless bounded plasmas, focusing on the concept of edge of chaos, the boundary that separates transient from asymptotic dynamics. We fully characterize an interior crisis at the end of a periodic window, thereby showing direct evidence of the collision between a chaotic attractor, a chaotic saddle, and the edge of chaos, formed by a period-3 unstable periodic orbit and its stable manifold. The edge of chaos persists after the interior crisis, when the global attractor of the system increases its size in the phase space.

  3. Primary Cutaneous Chrysosporium Infection following Ear Piercing: A Case Report

    Directory of Open Access Journals (Sweden)

    Poonkiat Suchonwanit

    2015-07-01

    Full Text Available Chrysosporium is a large genus of saprophytic fungi that is commonly found in the soil. Infection caused by this organism is rare in humans and typically occurs in immunocompromised patients. Primary cutaneous Chrysosporium infection is relatively rare and has been reported in a heart transplant patient. The prognosis is usually favorable, but very poor in the setting of persistent profound immunosuppression. We herein report a case of primary cutaneous Chrysosporium infection following ear piercing in an immunocompetent patient. It is important for clinicians to consider this condition in patients with slow-onset skin and soft tissue infection following cutaneous injury, even in an immunocompetent setting.

  4. Adolescent and Young Adult Tattooing, Piercing, and Scarification.

    Science.gov (United States)

    Breuner, Cora C; Levine, David A

    2017-09-18

    Tattoos, piercing, and scarification are now commonplace among adolescents and young adults. This first clinical report from the American Academy of Pediatrics on voluntary body modification will review the methods used to perform the modifications. Complications resulting from body modification methods, although not common, are discussed to provide the pediatrician with management information. Body modification will be contrasted with nonsuicidal self-injury. When available, information also is presented on societal perceptions of body modification. Copyright © 2017 by the American Academy of Pediatrics.

  5. Tattoos and Piercing: A Review for the Emergency Department Physician

    Directory of Open Access Journals (Sweden)

    William K. Mallon

    2011-05-01

    Full Text Available Tattoos and piercings are increasingly part of everyday life for large sections of the population, and more emergency physicians are seeing these body modifications (BM adorn their patients. In this review we elucidate the most common forms of these BMs, we describe how they may affect both the physical and psychological health of the patient undergoing treatment, and also try to educate around any potential pitfalls in treating associated complications. [West J Emerg Med. 2011;12(4:393–398.

  6. 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.

  7. 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.

  8. Gun Control in Australia: A Criminological Perspective

    Directory of Open Access Journals (Sweden)

    Rick Sarre

    2015-11-01

    Full Text Available In recent months there has been an upsurge in contributions to the popular press from social commentators insisting that guns make our nation safer. This essay questions these assertions. The paper provides evidence to support a contrary affirmation: that is, in order to have a reduction in gun violence, there needs to be a reduction in the number of guns generally, and a continuation of the legal controls that currently shape firearms policy in Australia.

  9. Cost Estimate for Gun Liner Emplacement

    Science.gov (United States)

    2011-08-01

    forge to near net outer diameter shape: 85-in long 3. Heat treat: quench and temper 4. Straighten to 0.005 in runout 5. Stress relieve 6. Grind ...steady rest 7. Cylindrically grind outer diameter (tapered) 8. Gun drill breech 9. Gun drill barrel inner diameter Detonation Velocity, Vd Gun...1.25-in inner diameter. Electrochemical machining (ECM) is already being employed to rifle M242 steel barrels by Alliant Techsystems (ATK). With this

  10. Research on Hot Gunning Repairing in Laboratory

    Institute of Scientific and Technical Information of China (English)

    CAO Feng; LONG Shigang; MENG Qingmin; SUN Jialin; HONG Yanruo

    2003-01-01

    The lining of blast furnace may be damaged partly,so that gunning repair is needed. The bonding strength of boundary surface between the repairing layer and remained lining of blast furnace has been studied by thermal simulation.The factors influencing the bonding strength are the ingredient gunning repair temperature,remained lining condition and water content of gunning refractory.The bonding strength decreases with the increases of remained lining temperature.

  11. Community gun safety in Central Pennsylvania.

    Science.gov (United States)

    Wargo, Christina; Erdman, Deborah A; Smith, Jill Gray; Widom, Kenneth; Reardon, Judith

    2013-01-01

    Firearm-related injuries are a public health issue in the United States. In rural Pennsylvania, it is a familiar way of life to have a gun or guns in the home. Safety behaviors along with gun storage in the home, specifically where there are young children (aged 6 years and younger), are a concern for this level I regional resource center in rural Pennsylvania. Head Start families were surveyed regarding gun safety habits before and after safety educational activities. A noteworthy number of families reported changing behaviors regarding better safety habits for storing and use of firearms in the home postsurvey.

  12. Current transmission and nonlinear effects in un-gated thermionic cathode RF guns

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, J. P. [Fermilab; Harris, J. R. [Air Force Weapons Lab

    2017-05-03

    Un-gated thermionic cathode RF guns are well known as a robust source of electrons for many accelerator applications. These sources are in principle scalable to high currents without degradation of the transverse emittance due to control grids but they are also known for being limited by back-bombardment. While back-bombardment presents a significant limitation, there is still a lack of general understanding on how emission over the whole RF period will affect the nature of the beams produced from these guns. In order to improve our understanding of how these guns can be used in general we develop analytical models that predict the transmission efficiency as a function of the design parameters, study how bunch compression and emission enhancement caused by Schottky barrier lowering affect the output current profile in the gun, and study the onset of space-charge limited effects and the resultant virtual cathode formation leading to a modulation in the output current distribution.

  13. Analysis of emittance compensation and simulation results to photo-cathode RF gun

    CERN Document Server

    LiuShengGuang

    2002-01-01

    The emittance compensation technology will be used on the photo-cathode RF gun for Shanghai SDUV-FEL. The space charge force and its effect on electron beam transverse emittance in RF gun is studied, the principle of emittance compensation in phase-space is discussed. The authors have designed a compensation solenoid and calculated its magnetic field distribution. Its performance has been studied by the code PARMELA. A simulation result indicates that the normalized transverse RMS emittance for electron beam of 1.5 nC is 1.612 pi mm centre dot mrad, electron energy E = 5.71 MeV

  14. Occupational accidents with piercing and cutting instruments in hospital nurses

    Directory of Open Access Journals (Sweden)

    Maria Helena Palucci Marziale

    2004-02-01

    Full Text Available Goals: To identify factors associated with occupational accidents caused by piercing and cutting instruments and to identify the consequences of these accidents.Methods: Descriptive field research. Data were obtained through semi-structured interviews with nurses who suffered accidents during one year in four hospitals at São Paulo State - Brazil. Results: factors associated with accidents were: work overload, poor quality material, inadequate disposal materials, professional negligence, clients’ aggressiveness, lack of attention and use of unsheathed needles. The accidents caused financial damages to the institutions as well as emotional and physical impairments to workers. Conclusions: There are several factors associated with accidents with piercing and cutting instruments. Therefore, preventive measures must be implemented according to the peculiarities of each work environment. Better care should be taken with the preparation of the professionals as well as with the information on risks from exposure to body/blood fluids they are given. A specific legislation is needed in our country in order to minimize this problem.

  15. Reflections on Dean Truman Pierce as Educator, Boss, Mentor and Friend

    Science.gov (United States)

    Watkins, J. Foster

    2012-01-01

    The author was invited to submit a reflective piece relative to his relationships with Dean Truman Pierce over the years to be presented on "The 30th Anniversary Celebration of the Truman Pierce Institute" at Auburn University. It was included in the program for the event.

  16. 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.

  17. Tattooing and body piercing--what motivates you to do it?

    Science.gov (United States)

    Antoszewski, Bogusław; Sitek, Aneta; Fijałkowska, Marta; Kasielska, Anna; Kruk-Jeromin, Julia

    2010-09-01

    Body ornamentation is becoming more and more popular, especially among young people. To establish the sociodemographic characteristics of people with tattoos or body piercing and to analyze the motivations for body ornamentation. The questionnaire studies were undertaken in Lodz--one of the largest cities in Poland. The data was collected from a group of 968 people, 476 of whom had a piercing and 492 a permanent tattoo. Statistical analysis revealed that in the group of people with a tattoo, 36.8% were female and 63.2% were male. Contrary proportions were noted among people with a piercing: 78.8% female and 21.2% male. Body piercing is significantly more popular among women while tattooing is more popular in men. Among adolescents, body piercing is performed considerably earlier than tattooing. The main reasons for body ornamenting in the Polish population are the desire to enhance one's individuality and the need to increase sexual attractiveness.

  18. Knowledge, Attitudes and Behaviour about Tattoo and Piercing among University Students

    Directory of Open Access Journals (Sweden)

    Yeşim Şenol

    2014-09-01

    Full Text Available Objective: Special Study Modules were firstly introduced five years ago at Akdeniz University Faculty of Medicine. The learning of basic concepts related with the skin and skin decorative arts, scientific presentations, informational society brochure were aimed in skin decorative arts such as tattoos and piercing, special study module. Methods: Four students admitted special study module opened in 2008-2009 academic year and 7 students in 2009-2010. Students organized a questionnaire to reveal the need for information on the subject. A questionnaire for tattoo and piercing were applied to students of Faculty of Medicine, Faculty of Fine Arts and the Faculty of Education. Presentation was performed in accordance with the requirements revealed by the questionnaire form and prepared leaflets were distributed to the students. Results: The prevalence of tattooing and body piercing was 12.3% in all students (n=154. 47.6% (n=10 for only tattoo, 42.9% (n=9 for only piercing, 9.6% (n=2 for both tattoo and piercing. Of the Medical Faculty students, 6.3% reported having both piercing and tattoo; 10.5% of the Faculty of Education students reported having both tattoo and piercing and 25.5% of the Faculty of Fine Arts students reported having both piercing and tattoo. Students of Medical Faculty gave more correct answers about the information of tattoo and piercing. Fine Arts students enjoyed getting tattoo and piercing more than other students and they applied these procedures at the maximum rate. Information levels about complications after the procedures were not adequate among the subjects practiced these applications. Conclusion: Our study emphasized the necessity of the studies for informing individuals about the art of skin decoration.

  19. Electromagnetic Gun With Commutated Coils

    Science.gov (United States)

    Elliott, David G.

    1991-01-01

    Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

  20. The Xygra gun simulation tool.

    Energy Technology Data Exchange (ETDEWEB)

    Garasi, Christopher Joseph; Lamppa, Derek C.; Aubuchon, Matthew S.; Shirley, David Noyes; Robinson, Allen Conrad; Russo, Thomas V.

    2008-12-01

    Inductive electromagnetic launchers, or coilguns, use discrete solenoidal coils to accelerate a coaxial conductive armature. To date, Sandia has been using an internally developed code, SLINGSHOT, as a point-mass lumped circuit element simulation tool for modeling coilgun behavior for design and verification purposes. This code has shortcomings in terms of accurately modeling gun performance under stressful electromagnetic propulsion environments. To correct for these limitations, it was decided to attempt to closely couple two Sandia simulation codes, Xyce and ALEGRA, to develop a more rigorous simulation capability for demanding launch applications. This report summarizes the modifications made to each respective code and the path forward to completing interfacing between them.

  1. 27 CFR 478.149 - Armor piercing ammunition manufactured or imported for the purpose of testing or experimentation.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Armor piercing ammunition... Armor piercing ammunition manufactured or imported for the purpose of testing or experimentation. The provisions of §§ 478.37 and 478.99(d) with respect to the manufacture or importation of armor piercing...

  2. Table-top laser-driven ultrashort electron and X-ray source: the CIBER-X source project

    Science.gov (United States)

    Girardeau-Montaut, Jean-Pierre; Kiraly, Bélà; Girardeau-Montaut, Claire; Leboutet, Hubert

    2000-09-01

    We report on the development of a new laser-driven table-top ultrashort electron and X-ray source, also called the CIBER-X source . X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulses at 213 nm. The e-gun is a standard Pierce diode electrode type, in which electrons are accelerated by a cw electric field of ˜11 MV/m up to a hole made in the anode. The photoinjector produces a train of 70-80 keV electron pulses of ˜0.5 nC and 20 A peak current at a repetition rate of 10 Hz. The electrons are then transported outside the diode along a path of 20 cm length, and are focused onto a target of thullium by magnetic fields produced by two electromagnetic coils. X-rays are then produced by the impact of electrons on the target. Simulations of geometrical, electromagnetic fields and energetic characteristics of the complete source were performed previously with the assistance of the code PIXEL1 also developed at the laboratory. Finally, experimental electron and X-ray performances of the CIBER-X source as well as its application to very low dose imagery are presented and discussed. source Compacte d' Impulsions Brèves d' Electrons et de Rayons X

  3. Concepts for a short wavelength rf gun

    Science.gov (United States)

    Kuzikov, S. V.; Shchelkunov, S.; Vikharev, A. A.

    2017-03-01

    Three concepts of an rf gun to be operated at 0.1-10 mm wavelengths are considered. In all the concepts, the rf system exploits an accelerating traveling wave. In comparison with a classical decimeter standing-wave rf gun, we analyze the advantages of new concepts, available rf sources, and achievable beam parameters.

  4. On the theory of photocathode rf guns

    Institute of Scientific and Technical Information of China (English)

    GAO Jie

    2009-01-01

    In this paper we give a set of analytical formulae to describe the characteristics of photocathode rf guns at any rf frequencies, such as energy, energy spread, bunch length, out going current, and emittance etc.as functions of the laser injection phase, which are useful in the design and practical operation of rf guns.

  5. Gun Control: The Debate and Public Policy.

    Science.gov (United States)

    Watkins, Christine

    1997-01-01

    Provides an overview and background information on the debate over gun control, as well as several teaching ideas. Handouts include a list of related topics drawn from various disciplines (economics, U.S. history), seven arguments for and against gun control, and a set of policy evaluation guidelines. (MJP)

  6. Beam characterization for the field-emitter-array cathode-based low-emittance gun

    Directory of Open Access Journals (Sweden)

    S. C. Leemann

    2007-07-01

    Full Text Available A 1   Å x-ray free electron laser can be operated at 6 GeV provided a very high brightness electron beam. Therefore, Paul Scherrer Institute has initiated development of the low-emittance gun based on field emission. A field-emitter array (FEA is expected to deliver high peak current while reducing the source emittance to levels close to the thermal limit. A 100 keV gun test stand has been designed in order to gain experience with electron bunches emitted by pulsed FEAs, investigate emittance compensation, and develop diagnostic procedures to characterize the beam. First FEA samples have been installed and pulsed in the gun; the emitted bunches have been accelerated and characterized. We present results acquired with the first FEA samples.

  7. Femtosecond precision measurement of laser-rf phase jitter in a photocathode rf gun

    Science.gov (United States)

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

    2017-03-01

    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.

  8. Study of heat transfer conditions at the wall of an ingot heated by electron gun; Etude des conditions d'echange thermique a la paroi d'un lingot chauffe par un canon a electrons

    Energy Technology Data Exchange (ETDEWEB)

    Saturnin, A.; Triffart, B. [CEA Vallee du Rhone, Dept. de Technologie de l' Enrichissement (DCC/DTE/STS), 26 - Pierrelatte (France)

    2000-07-01

    A metal confined in a crucible is heated by an electron beam to produce metallic vapor. Only a small proportion of the electron beam energy is used to vaporize the metal. Another portion is lost because of backscattered electrons and thermal radiation of the ingot. The remaining energy is transmitted by convection and conduction to the water cooled crucible. The knowledge of this energy, and particularly its spatial distribution, is important. The magnitude of the heat flux can be analyzed to ensure component integrity. The spatial flux distribution provides information about the coolant system homogeneity, which is related to the position of the ingot in the crucible and the electron beam alignment. These data are useful for controlling operating conditions. In the present method, the heat flux at the crucible wall is identified by conventional measurements (thermocouples, flowmeter) and an inverse method. This approach makes it unnecessary to model complex mechanisms in the liquid metal pool, limiting the study to the heat transfers inside the crucible. Calculation of the flux at a given point of the crucible wall requires three essential data: coolant system temperature Te, crucible temperature Tmes at the measurement point Pmes and temperature sensitivity at this point to heat flux variations at the wall. This characteristic is also called the sensitivity coefficient. It is obtained by modeling heat transfers in the crucible (convective with coolant system, conductive in the crucible) with the boundary conditions Te = 0 K and {phi} 1 Wm{sup -2}. This approach is a simple application of the function specification method, which is a reference method in inverse problems. The problem is assumed to be linear and stationary because of the high thermal crucible conductivity and the measurement locations (close to the wall). If the sensitivity coefficient is known, the heat flux can be calculated by equation (1). Figure 2 shows an example of variations in Tmes and Te

  9. 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.

  10. Sequential injection gas guns for accelerating projectiles

    Science.gov (United States)

    Lacy, Jeffrey M [Idaho Falls, ID; Chu, Henry S [Idaho Falls, ID; Novascone, Stephen R [Idaho Falls, ID

    2011-11-15

    Gas guns and methods for accelerating projectiles through such gas guns are described. More particularly, gas guns having a first injection port located proximate a breech end of a barrel and a second injection port located longitudinally between the first injection port and a muzzle end of the barrel are described. Additionally, modular gas guns that include a plurality of modules are described, wherein each module may include a barrel segment having one or more longitudinally spaced injection ports. Also, methods of accelerating a projectile through a gas gun, such as injecting a first pressurized gas into a barrel through a first injection port to accelerate the projectile and propel the projectile down the barrel past a second injection port and injecting a second pressurized gas into the barrel through the second injection port after passage of the projectile and to further accelerate the projectile are described.

  11. Compact THz radiation source based on photocathode RF gun

    Institute of Scientific and Technical Information of China (English)

    URAKAWA; JunJi

    2011-01-01

    Terahertz (THz) science and technology have already become the research highlight at present. In this paper, we put forward a proposal to generate THz radiation at tens of MW peak power. As a result of the ultrafast laser and the high accelerating field of photocathode RF gun, we can generate and accelerate an electron beam to several MeV, of which the bunch length is less than sub-ps. When the short electron bunches are injected into the wiggler, THz radiation based on Coherent Synchrotron Radiation could be achieved with tens of MW peak power. The whole THz FEL facility can be scaled to the size of a tabletop.

  12. ERLP Gun Commissioning Beamline Design

    CERN Document Server

    Holder, D J; Hannon, F E

    2004-01-01

    The 4GLS project is a novel next-generation solution for a UK national light source. It is based on an energy recovery linac (ERL) operating at high average beam currents up to 100 mA and with compression schemes producing pulses in the 10 - 100 fs range. This challenging accelerator technology, new to Europe, necessitates a significant R&D programme and a major part of this is a low-energy prototype, the ERLP, which is currently under construction at Daresbury Laboratory, in the north-west of England. The first components of ERLP to be built will be the DC photocathode gun and low-energy beam transport and diagnostics. The gun will initially be operated with a diagnostic beamline in order to measure the properties of the high-brightness beams generated as fully as possible. This will allow comparison of its performance with the results of multi-particle tracking codes, prior to its integration into the ERLP machine. The diagnostic beamline will include diagnostics for measuring the transverse and longitu...

  13. The elbe accelerator facility starts operation with the superconducting rf gun

    CERN Document Server

    Xiang, R; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Teichert, J; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2010-01-01

    As the first superconducting rf photo-injector (SRF gun) in practice, the FZD 3+1/2 cell SRF gun is successfully connected to the superconducting linac ELBE. This setting will improve the beam quality for ELBE users. It is the first example for an accelerator facility fully based on superconducting RF technology. For high average power FEL and ERL sources, the combination of SRF linac and SRF gun provides a new chance to produce beams of high average current and low emittance with relative low power consumption. The main parameters achieved from the present SRF gun are the final electron energy of 3 MeV, 16 μA average current, and rms transverse normalized emittances of 3 mm mrad at 77 pC bunch charge. A modified 3+1/2 cell niobium cavity has been fabricated and tested, which will increase the rf gradient in the gun and thus better the beam parameters further. In this paper the status of the integration of the SRF gun with the ELBE linac will be presented, and the latest results of the beam experiments will ...

  14. Rotating black holes pierced by a cosmic string

    CERN Document Server

    Kubiznak, David

    2015-01-01

    A rotating black hole threaded by an infinitely long cosmic string is studied in the framework of the Abelian Higgs model. We show that contrary to a common belief in the presence of rotation the backreaction of the string does not induce a simple conical deficit. This leads to new distinct features of the Kerr--string system such as modified ISCO or shifted ergosphere, though these effects are most likely outside the range of observational precision. For an extremal rotating black hole, the system exhibits a first-order phase transition for the gravitational Meissner effect: small black holes exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon, whereas the horizon of large black holes is pierced by the vortex. A brief review prepared for the MG14 Proceedings.

  15. 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

    2016-01-01

    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. PMID:27269024

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

    Science.gov (United States)

    Kivisto, Aaron J

    2017-06-01

    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%.

  17. 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.

  18. Ulcer piercing: cleansing of complicated diabetic neuropathic foot ulcers by positive pressure irrigation.

    Science.gov (United States)

    Cavallini, M

    2014-02-01

    To demonstrate the efficacy of the ulcer piercing procedure, which allows constant cleansing of the ulcer and facilitates a positive pressure irrigation of any pierced hidden tracts, in order to reduce the negative impact of stasis on wound healing. We designed a surgical procedure of ulcer piercing and drainage with a silastic tube, which allows positive pressure irrigation of any pierced tracts. This procedure was performed in a continuous series of 25 selected diabetic patients affected by a Wagner stage 3 ulcer of the toe (n=16), metatarsal midfoot (n=5) and plantar Charcot foot (n=4), and with adequate foot arterial blood supply. Within 6 months of the ulcer piercing procedure, 23/25 of ulcers had completely healed. In two further cases, the ulcer piercing ring was still in place after 3 and 5 months, progressively healing with no active signs of infection. Taking into consideration the advantages and the lack of side effects afforded by this procedure, ulcer piercing represents a small but effective step towards an easier and safer approach to treating complicated diabetic neuropathic foot ulcers with adequate arterial blood supply. There were no external sources of funding for this study. The author has no conflicts of interest to declare with regard to the manuscript or its content.

  19. Large density amplification measured on jets ejected from a magnetized plasma gun

    OpenAIRE

    Yun, Gunsu S.; You, Setthivoine; Bellan, Paul M.

    2007-01-01

    Observation of a large density amplification in the collimating plasma jet ejected from a coplanar coaxial plasma gun is reported. The jet velocity is ~30 km s^-1 and the electron density increases from ~10^20 to 10^(22–23) m^-3. In previous spheromak experiments, electron density of the order 10^(19–21) m^-3 had been measured in the flux conserver region, but no density measurement had been reported for the source gun region. The coplanar geometry of our electrodes permits direct observation...

  20. Reaksi Radang pada Lidah dengan Tongue Piercing (Kajian in vivo pada Lidah Tikus Jantan Sprague dawley

    Directory of Open Access Journals (Sweden)

    Feby Aryani

    2015-10-01

    Full Text Available Today tongue piercing has become increasingly popular in the society. Several case reports associated with tongue piercing have presented various complications, such as tooth fracture, viral infection (HIV, Hepatitis B and C, herpes simplex, Epstein Barr, fungal infection (Candida spp, pain altered taste, edema, paresthesis, gingival recession, prolonged bleeding, contact dermatitis. However, there is no scientific evidence to reveal hispathological change in tongue piercing. The aim of this study is to investigate the inflammation response to tongue piercing in Spraque Dawley rats. Eighteen Sprague Dawley rats were divided into one control group of 3 untreated rats and three experimental groups of 5 rats each, according to the duration of tongue piercing until the end of 1st week (A, 6th week (B and 12th week (C. At the end of treatments, the rats were anesthetized and sacrifices. Paraffin embedded tongue specimens were prepared for histological examination with H&E stainig. The number of inflammatory cells (PMN leukocytes, lymphocytes, macrophages was counted under light microscope. All experimental procedures were carried out under approval of study protocol by the Health and Medical Research Ethics Committee, Faculty of Medicine, Gadjah Mada University, Yogyakarta. The results of this study indicated that the number of PMN leukocytes, lymphocytes, and macrophages was increasing to the 1st week after tongue piercing. The number of lymphocytes and macrohpages was still increasing after 6th and 12th weeks of piercing, but the bumber of PMN leukocytes, lymphocytes, and macrophages between the groups of 1st, 6th, and 12th weeks after piercing. It was concluded that tongue piercing induce inflammatory response for 12 weeks in Sprague Dawley rats.

  1. Homopolar Gun for Pulsed Spheromak Fusion Reactors II

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T

    2004-06-14

    A homopolar gun is discussed that could produce the high currents required for pulsed spheromak fusion reactors even with unit current amplification and open field lines during injection, possible because close coupling between the gun and flux conserver reduces gun losses to acceptable levels. Example parameters are given for a gun compatible with low cost pulsed reactors and for experiments to develop the concept.

  2. 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.

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. 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.

  8. Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter.

    Science.gov (United States)

    Vizir, A V; Tyunkov, A V; Shandrikov, M V; Oks, E M

    2010-02-01

    The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10(9) cm(-3) at an operating gas pressure in the vacuum chamber of less than 2x10(-2) Pa. The device features high power efficiency, design simplicity, and compactness.

  9. Face piercing (body art: choosing pleasure vs. possible pain and posture instability

    Directory of Open Access Journals (Sweden)

    Eric eMatheron

    2011-09-01

    Full Text Available Piercings (body art, i.e. with jewelry are more and more widespread. They can induce various complications such as infections, allergies, headaches, and various skin, cartilage, or dental problems which will lead to economic effects on health-care systems. We draw attention to other possible side effects resulting from face piercing complications such as eye misalignment, decreased postural control efficiency, and nonspecific chronic back pain. We found that the origin was pierced jewelry on the face. Removing the jewelry restored eye alignment, improved postural control, and alleviated back pain in a lasting way. This observation is important for health; further investigations would be of interest.

  10. Application of Hard Coatings for Improved Tribological Performance of Blanking and Piercing Tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2010-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  11. 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 guns per capita per country and crime rate (r = .33), or between mental illness and crime rate (r = 0.32; P = .11). In a linear regression model with firearm-related deaths as the dependent variable with gun ownership and mental illness as independent covariates, gun ownership was a significant predictor (P 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.

  12. "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.

  13. Texas youth stage rally against guns

    Institute of Scientific and Technical Information of China (English)

    Mary; Alice; Robbins; 李小平

    2000-01-01

    Young Texans Against Gun Violence rallied atthe State Capitol on Monday and called for the Legisla-ture to pass laws that would make it more difficult toget guns.“It is time for our state Legislature to pass laws tohelp protect us,”Marianne Moreno,a high school se-nior from the Dallas area,told a crowd of about 125students who attended the“Packing Peace Rally.”“As Texas law stands today,anyone—even acriminal—can walk into a gun show and purchase asemi-automatic weapon or any other type of firearm,...

  14. 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.

  15. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope. Specifications / Capabilities: Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  16. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope.Specifications / Capabilities:Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  17. Ultrafast Time-Resolved Electron Diffraction with Megavolt Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; /SLAC; Rudakov, F.M.; /Brown U.; Dowell, D.H.; Schmerge, J.F.; /SLAC; Cardoza, J.D.; /Brown U.; Castro, J.M.; Gierman, S.M.; Loos, H.; /SLAC; Weber, P.M.; /Brown U.

    2006-10-24

    An rf photocathode electron gun is used as an electron source for ultrafast time-resolved pump-probe electron diffraction. We observed single-shot diffraction patterns from a 160 nm Al foil using the 5.4 MeV electron beam from the Gun Test Facility at the Stanford Linear Accelerator. Excellent agreement with simulations suggests that single-shot diffraction experiments with a time resolution approaching 100 fs are possible.

  18. 75 FR 32855 - Safety Zone; Pierce County, WA, Department of Emergency Management, Regional Water Exercise

    Science.gov (United States)

    2010-06-10

    ... Management, Regional Water Exercise AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Pierce County, Washington, Department of Emergency Management is sponsoring a Regional Water Rescue... County, Washington, Department of Emergency Management is sponsoring a Regional Water Rescue Exercise...

  19. Pierce's Memorandum Account Book Designed for Farmers, Mechanics, and All People

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a memorandum account book containing advertisements for medications developed by Dr. R.V. Pierce, former owner of St. Vincent Island.

  20. Pierce and Franz Lake National Wildlife Refuges: Narrative Report: 1991: Calendar Year

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Pierce National Wildlife Refuge outlines Refuge accomplishments for the 1991 calendar year. The report begins by giving Refuge highlights...

  1. Selforganisation and dynamics peculiarities of intense electron beams in compact crossed fields systems

    CERN Document Server

    Agafonov, A V; Fedorov, V M

    2001-01-01

    The review of the results of computer simulations of electron flow self-organisation inside magnetically isolated coaxial diodes (magnetron gun) is given. Magnetron guns of usual and inverted polarities are considered.

  2. Waterfowl habitat survey : Canvasback Gun Club : 1964

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey of the submergent and emergent aquatics growing in the marsh on the Canvasback Gun Club in Nevada. The marsh portion of the...

  3. Waterfowl habitat survey : Canvasback Gun Club : 1965

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey of the submergent and emergent aquatics growing in the marsh on the Canvasback Gun Club in Nevada. As stated in previous years of...

  4. Waterfowl habitat survey : Canvasback Gun Club : 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Since the last vegetative survey in 1965, the marsh at Canvasback Gun Club has remained virtually unchanged. The Arthur-Johnson Ponds produced most of the waterfowl...

  5. Arc Plasma Gun With Coaxial Powder Feed

    Science.gov (United States)

    Zaplatynsky, Isidor

    1988-01-01

    Redesigned plasma gun provides improved metallic and ceramic coatings. Particles injected directly through coaxial bore in cathode into central region of plasma jet. Introduced into hotter and faster region of plasma jet.

  6. Detonator assembly for oil well perforating gun

    Energy Technology Data Exchange (ETDEWEB)

    Regalbuto, J.A.

    1981-02-18

    A safe/arm detonator assembly for use with an oil well perforating gun assembly has 2 housing members isolated from well-bore fluid which are rotatable from a safe position wherein a detonator and a booster are held out of alignment, to an armed position wherein the detonator and booster are moved into alignment. The detonator assembly is further arranged to be installed in a well perforating gun assembly such that the gun assembly may be transported with the detonator assembly in the safe position, and rotated to the armed position at the well site without disassembling the gun assembly. A safety pin may protrude from one of the housing members across a cavity between the members to cover and protect the booster from accidental detonation when the detonator assembly is in the safe position. The detonator and booster cavities may be held aligned by a detent ball. 16 claims.

  7. Ballistic Rail Gun Soft Recovery Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Ballistic Rail Gun Soft Recovery Facility accommodates a 155mm Howitzer, fired horizontally into a 104-foot long water trough to slow the projectile and recover...

  8. Uudised : Guns N' Roses Soomes. Valmis ulmeraadio

    Index Scriptorium Estoniae

    2006-01-01

    Ameerika hard-rock-bändi Guns N' Roses kontserdist 5. juulil Hartwall Areenal Soomes. Kord kuus on Ulmeplaatide kodulehekülel www. ulmeplaadid.ee võimalus kuulata ulmeraadiot, kus esitusel eesti kergemuusika

  9. Waterfowl habitat survey : Canvasback Gun Club : 1962

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is about an investigation that was done to determine the quantity and species of submergent vegetation in the marsh area on the Canvasback Gun Club in...

  10. Uudised : Guns N' Roses Soomes. Valmis ulmeraadio

    Index Scriptorium Estoniae

    2006-01-01

    Ameerika hard-rock-bändi Guns N' Roses kontserdist 5. juulil Hartwall Areenal Soomes. Kord kuus on Ulmeplaatide kodulehekülel www. ulmeplaadid.ee võimalus kuulata ulmeraadiot, kus esitusel eesti kergemuusika

  11. Direct launch using the electric rail gun

    Science.gov (United States)

    Barber, J. P.

    1983-01-01

    The concept explored involves using a large single stage electric rail gun to achieve orbital velocities. Exit aerodynamics, launch package design and size, interior ballistics, system and component sizing and design concepts are treated. Technology development status and development requirements are identified and described. The expense of placing payloads in Earth orbit using conventional chemical rockets is considerable. Chemical rockets are very inefficient in converting chemical energy into payload kinetic energy. A rocket motor is relatively expensive and is usually expended on each launch. In addition specialized and expensive forms of fuel are required. Gun launching payloads directly to orbit from the Earth's surface is a possible alternative. Guns are much more energy efficient than rockets. The high capital cost of the gun installation can be recovered by reusing it over and over again. Finally, relatively inexpensive fuel and large quantities of energy are readily available to a fixed installation on the Earth's surface.

  12. The electric rail gun for space propulsion

    Science.gov (United States)

    Bauer, D. P.; Barber, J. P.; Vahlberg, C. J.

    1981-01-01

    An analytic feasibility investigation of an electric propulsion concept for space application is described. In this concept, quasistatic thrust due to inertial reaction to repetitively accelerated pellets by an electric rail gun is used to propel a spacecraft. The study encompasses the major subsystems required in an electric rail gun propulsion system. The mass, performance, and configuration of each subsystem are described. Based on an analytic model of the system mass and performance, the electric rail gun mission performance as a reusable orbital transfer vehicle (OTV) is analyzed and compared to a 30 cm ion thruster system (BIMOD) and a chemical propulsion system (IUS) for payloads with masses of 1150 kg and 2300 kg. For system power levels in the range from 25 kW(e) to 100 kW(e) an electric rail gun OTV is more attractive than a BIMOD system for low Earth orbit to geosynchronous orbit transfer durations in the range from 20 to 120 days.

  13. Arc-driven rail gun research

    Science.gov (United States)

    Ray, P. K.

    1984-01-01

    The equations describing the performance of an inductively-driven rail gun are analyzed numerically. Friction between the projectile and rails is included through an empirical formulation. The equations are applied to the experiment of Rashleigh and Marshall to obtain an estimate of energy distribution in rail guns as a function of time. The effect of frictional heat dissipation on the bore of the gun is calculated. The mechanism of plasma and projectile acceleration in a dc rail gun is described from a microscopic point of view through the establishment of the Hall field. The plasma conductivity is shown to be a tensor indicating that there is a small component of current parallel to the direction of acceleration. The plasma characteristics are evaluated as a function of plasma mass through a simple fluid mechanical analysis of the plasma. By equating the energy dissipated in the plasma with the radiation heat loss, the properties of the plasma are determined.

  14. Waterfowl habitat survey : Canvasback Gun Club : 1963

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey of the submergent and emergent aquatics growing in the marsh on the Canvasback Gun Club in Nevada. The marsh portion of the...

  15. Modelling Effectiveness of Machine Gun Fire

    OpenAIRE

    Dutta, D.; S. Sabhanval

    2002-01-01

    Machine gun is an effective infantry weapon which can cause heavy damage to enemy targets, if sited in a tactically favourable position. It can be engaged effectively against both static and moving targets. The paper deals with the determination of target vulnerability under effective machine gun fire considering relevant tactical parameters, eg, target aiming point, trajectory of fire, sweep angle, target frontage, posture, direction of attack, etc.

  16. Modelling Effectiveness of Machine Gun Fire

    Directory of Open Access Journals (Sweden)

    D. Dutta

    2002-04-01

    Full Text Available Machine gun is an effective infantry weapon which can cause heavy damage to enemy targets, if sited in a tactically favourable position. It can be engaged effectively against both static and moving targets. The paper deals with the determination of target vulnerability under effective machine gun fire considering relevant tactical parameters, eg, target aiming point, trajectory of fire, sweep angle, target frontage, posture, direction of attack, etc.

  17. Cobalt-Base Alloy Gun Barrel Study

    Science.gov (United States)

    2014-07-01

    are presented in Section 5. 2. Materials and methods The composition of the cobalt -base alloy (CBA) is presented in Table 1. The production of this... Cobalt -Base Alloy Gun Barrel Study by William S. de Rosset and Jonathan S. Montgomery ARL-RP-0491 July 2014 A reprint...21005-5069 ARL-RP-0491 July 2014 Cobalt -Base Alloy Gun Barrel Study William S. de Rosset and Jonathan S. Montgomery Weapons and Materials

  18. Instantaneous mechanical fastening of quasi-isotropic CFRP laminates by a self-piercing rivet

    OpenAIRE

    上田, 政人; 三宅, 崇太郎; 長谷川, 寛幸; 平野, 義鎭; Ueda, Masahito; Miyake, Sotaro; Hasegawa, Hiroyuki; Hirano, Yoshiyasu

    2012-01-01

    A modified self-piercing rivet (SPR) has been proposed to mechanically fasten CFRP laminates. The modified SPR consists of a rivet body and two flat washers. The two flat washers were used to suppress delamination in the CFRP laminates at the point of piercing. The advantages of the modified SPR for fastening CFRP laminates are instantaneous process time and low cost. Any pretreatments such as surface treatments or hole drilling are not required. In this study, the viability of the modified S...

  19. 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

  20. A Simulation for the Punchless Piercing Process using Lemaitre Damage Model

    Science.gov (United States)

    Lee, Sang Wook; Pourboghrat, Farhang

    2005-08-01

    The punchless piercing is a process that uses highly pressurized fluid instead of the conventional punch to make holes into the sheet metal. This process has many advantages over the conventional method for piercing various shaped holes into very thin strips of metal, composite, etc. An important cost advantage comes from not having to use a punch. Another important advantage comes from the top quality of pierced holes produced by punchless piercing, as no secondary finishing process will be needed for removing burrs typically found in conventional cutting processes. The ABAQUS/Explicit FEM code coupled with Lemaitre damage model has been used to more precisely characterize the punchless piercing process. The formulation adopted for this purpose focuses on the development of an efficient stress integration algorithm and development of a user material subroutine (VUMAT). For verification, the computed results have been compared with those of the experimental results in the literature and shown to be in good agreement with each other. The results obtained from this work are expected to be of significant interest to automotive and aerospace industries interested in using the punchless piercing process.

  1. Profile of oral piercing users and implications resulting from its use

    Directory of Open Access Journals (Sweden)

    Jeferson da Costa Marchiori

    2009-01-01

    Full Text Available Objective: To identify the profile of oral piercing users and the possible implications resulting from its use, as well as explaining to dentists about the possible consequences to their patients as a result of wearing this type of jewelry in the oral region.Methods: Fifty-one oral piercing users were interviewed. They were aged between 18 and 42 year, from different social classes, and resident in the city of Santa Maria, Rio Grande do Sul, Brazil.Results: Based on the questionnaires analyzed, the majority of users had tongue or lip piercing as a way to express identity, and 45% reported the occurrence of some type of oral and/or general alteration associated with the use of piercings. Conclusion: The majority of alterations are harmful to the piercing user’s health, therefore, professionals in the Dentistry area must be warnedto explain to their patients, who use oral piercings, about the consequences that may occur and the need for special care to ameliorate these problems.

  2. Modified Contact Line Dynamics about a Surface-Piercing Hydrofoil

    Science.gov (United States)

    Grivel, Morgane; Jeon, David; Gharib, Morteza

    2016-11-01

    The contact line around a surface-piercing hydrofoil is modified by introducing alternating hydrophobic and hydrophilic bands along one side of the body. These bands are either aligned perpendicular or parallel to the flow direction. The other side of the hydrofoil is un-patterned and retains its original, uniformly hydrophilic properties. The hydrofoil is mounted onto air bearings, such that it can freely move side-to-side in the water tunnel. A force sensor is attached to the setup via a universal joint in order to measure the forces acting on the body for several Reynolds numbers (ranging from 104 to 105) and angles of attack (ranging from -10o to 10o) . Cameras are also used to record the resulting flow structures and free surface elevation. The generation of wave trains and an altered free-surface elevation (also associated with the generation of surface waves) are observed over a wide range flow conditions. Force measurements elucidate how introducing these flow features impacts the forces acting on the hydrofoil, specifically with regards to the generation of lateral forces due to the asymmetric wetting conditions on either side of the hydrofoil. Work is funded by ONR Grant N00014-11-1-0031 and NSF GRFP Grant DGE-1144469.

  3. Nonlinear diffraction effects around a surface-piercing structure

    Energy Technology Data Exchange (ETDEWEB)

    Lalli, F.; Mascio, A. Di; Landrini, M. [Istituto Nazionale per Studi ed Esperienze di Architettura Navale, Rome (Italy)

    1995-12-31

    In the present paper the interaction of a wave system with a submerged or surface piercing body is studied. The wave diffraction caused by a cylinder in finite depth water and by a shoal is been computed and the results are compared with analytical solutions and experimental data. The problem is analyzed numerically in the frame of irrotational incompressible flow hypothesis. Both the linearized and the fully nonlinear mathematical models are studied. The numerical solution is gained by means of a mixed panel-desingularized formulation. An explicit time-marching algorithm updates the wave elevation and the potential at the free surface. In all cases, the numerical simulation mirrors the experimental data. In the case of the diffraction around a cylinder, the simulation confirms and extends the theoretical results of the second order analysis (Kriebel 1990, 1992): the linear model yields a very good estimation of the force amplitude acting on the body, while the wave profiles are poorly predicted when compared with the fully nonlinear simulation and the experimental data.

  4. 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…

  5. 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…

  6. Magnetic Bubble Expansion Experimental Investigation Using a Compact Coaxial Magnetized Plasma Gun

    Science.gov (United States)

    Zhang, Yue; Lynn, Alan; Hsu, Scott; Li, Hui; Liu, Wei; Gilmore, Mark; Watts, Christopher

    2009-11-01

    The poster will first discuss the construction and improved design of a compact coaxial magnetized plasma gun. The plasma gun is used for experimental studies of magnetic bubble expansion into a lower pressure background plasma, which as a model for extragalactic radio lobes and solar coronal mass ejections. In this experiment, the plasma bubble's density, electron temperature, and propagation speed are measured by using a multiple-tipped langmuir probe. Also a three axis B-dot probe array is used to measure the magnetic field in three dimensions during the expansion process. In this poster experiment setup and data will be provided. Finally the comparison with the simulation result will be made.

  7. Direct morphological comparison of vacuum plasma sprayed and detonation gun sprayed hydroxyapatite coatings for orthopaedic applications.

    Science.gov (United States)

    Gledhill, H C; Turner, I G; Doyle, C

    1999-02-01

    Hydroxyapatite coatings on titanium substrates were produced using two thermal spray techniques vacuum plasma spraying and detonation gun spraying. X-ray diffraction was used to compare crystallinity and residual stresses in the coatings. Porosity was measured using optical microscopy in conjunction with an image analysis system. Scanning electron microscopy and surface roughness measurements were used to characterise the surface morphologies of the coatings. The vacuum plasma sprayed coatings were found to have a lower residual stress, a higher crystallinity and a higher level of porosity than the detonation gun coatings. It is concluded that consideration needs to be given to the significance of such variations within the clinical context.

  8. Simulations of S-band RF gun with RF beam control

    Science.gov (United States)

    Barnyakov, A. M.; Levichev, A. E.; Maltseva, M. V.; Nikiforov, D. A.

    2017-08-01

    The RF gun with RF control is discussed. It is based on the RF triode and two kinds of the cavities. The first cavity is a coaxial cavity with cathode-grid assembly where beam bunches are formed, the second one is an accelerating cavity. The features of such a gun are the following: bunched and relativistic beams in the output of the injector, absence of the back bombarding electrons, low energy spread and short length of the bunches. The scheme of the injector is shown. The electromagnetic field simulation and longitudinal beam dynamics are presented. The possible using of the injector is discussed.

  9. Waves generated in the vicinity of an argon plasma gun in the ionosphere

    Science.gov (United States)

    Cahill, L. J., Jr.; Arnoldy, R. L.; Lysak, R. L.; Peria, W.; Lynch, K. A.

    1993-01-01

    Wave and particle observations were made in the close vicinity of an argon plasma gun carned to over 600 km altitude on a sounding rocket. The gun was carned on a subpayload, separated from the main payload early in the flight. Twelve-second argon ion ejections were energized alternately with a peak energy of 100 or 200 eV. They produced waves, with multiple harmonics, in the range of ion cyclotron waves, 10 to 1000 Hz at rocket altitudes. Many of these waves could not be identified as corresponding to the cyclotron frequencies of any of the ions, argon or ambient, known to be present. In addition, the wave frequencies were observed to rise and fall and to change abruptly during a 12-s gun operation. The wave amplitudes, near a few hundred Hertz, were of the order of O. 1 V/m. Some of the waves may be ion-ion hybrid waves. Changes in ion populations were observed at the main payload and at the subpayload during gun operations. A gun-related, field-aligned, electron population also appeared.

  10. Measurement and Analysis of Mechanical Admittance of Gun-Shoulder System

    Institute of Scientific and Technical Information of China (English)

    BAO Jian-dong; WANG Chang-ming; HE Yun-feng

    2008-01-01

    Lots of factors have influence on the firing accuracy of automatic weapon. During firing, the movement state of gun-shoulder system can be varied due to the impulsion of powder gases and the impact of moving parts, resulting in a gunpoint being deviated from initial value to decrease the firing accuracy of weapon. The development of intelligent con-trolling gun carriage for weapon system is necessary for reflect its automatic firing accuracy objectively. An electronic mea-suring system for measuring the receiving force and movement of gun-shoulder system under initiative state is built based on the characteristics of standing non-rest automatic weapon. The constitutes of measuring system and the correction method of shoulder receiving force are described, and the mechanical admittance function of gun-shoulder system is ob-tained using dectronicaUy measured data, the modal identification of admittance functions of gun-shoulder system is made by adopting the orthogonal component method, and the key difference between the passive state and initiative state of standing non-rest automatic weapon is discussed.

  11. Coaxial carbon plasma gun deposition of amorphous carbon films

    Science.gov (United States)

    Sater, D. M.; Gulino, D. A.; Rutledge, S. K.

    1984-01-01

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented.

  12. Demonstration of Cathode Emittance Dominated High Bunch Charge Beams in a DC gun-based Photoinjector

    CERN Document Server

    Gulliford, Colwyn; Bazarov, Ivan; Dunham, Bruce; Cultrera, Luca

    2015-01-01

    We present the results of transverse emittance and longitudinal current profile measurements of high bunch charge (greater than or equal to 100 pC) beams produced in the DC gun-based Cornell Energy Recovery Linac Photoinjector. In particular, we show that the cathode thermal and core beam emittances dominate the final 95% and core emittance measured at 9-9.5 MeV. Additionally, we demonstrate excellent agreement between optimized 3D space charge simulations and measurement, and show that the quality of the transverse laser distribution limits the optimal simulated and measured emittances. These results, previously thought achievable only with RF guns, demonstrate that DC gun based photoinjectors are capable of delivering beams with sufficient single bunch charge and beam quality suitable for many current and next generation accelerator projects such as Energy Recovery Linacs (ERLs) and Free Electron Lasers (FELs).

  13. Prevalence of tattooing and body piercing in Germany and perception of health, mental disorders, and sensation seeking among tattooed and body-pierced individuals.

    Science.gov (United States)

    Stirn, Aglaja; Hinz, Andreas; Brähler, Elmar

    2006-05-01

    The objective of this study was to obtain data on the incidence and relationship of psychological factors to tattooing and body piercing from a large and representative sample of German citizens (N=2043). Representative data (sample age range=14-93 years) were evaluated with respect to health-related quality of life (SF-36), mental health (General Health Questionnaire), mental disorders (Patient Health Questionnaire), and sensation seeking (Arnett Inventory of Sensation Seeking). The prevalence of tattooing and that of body piercing in the general German population are 8.5% and 6.5%, respectively. Individuals aged between 14 and 24 years display the highest rate of body piercings or tattoos (females, 41%; males, 27%). Within the group of individuals aged between 14 and 44 years, unemployment and nonaffiliation to a church are positively correlated, tattooing is significantly correlated with the perception of reduced mental health, and both tattooing and body piercing are correlated with significantly increased sensation-seeking behavior. Next to being motivated by fashion and the urge to fit in with one's peers, the major reasons for body modification practices in the German population appear to be negatively perceived conditions of life, reduced social integration, and increased sensation-seeking behavior.

  14. Pericondrite por piercing: relato de casos e revisão da literatura Ear piercing perichondritis: case reports and literature review

    Directory of Open Access Journals (Sweden)

    Ernesto N. Takahashi

    2004-10-01

    Full Text Available A pericondrite é uma infecção que envolve o pericôndrio do pavilhão auricular. Desencadeada pelo piercing, é secundária a uma reação alérgica ao níquel. O diagnóstico é essencialmente clínico, porém a realização de cultura e antibiograma é fundamental. Os patógenos freqüentemente envolvidos são germes Gram negativos (Pseudomonas aeruginosa. Os autores apresentam 3 casos de pericondrite por piercing atendidos no ambulatório de otorrinolaringologia e realizam uma revisão da literatura.Auricular perichondritis is a complication related to ear piercing, caused by the hypersensitivity to nickel. The diagnosis is essentially based on clinical findings. The most pathogen frequently involved is Pseudomonas aeruginosa. Culture is important to determine the antibiotic susceptibility. We report 3 cases of ear piercing associated perichondritis and present a literature review.

  15. STREAK CAMERA MEASUREMENTS OF THE APS PC GUN DRIVE LASER

    Energy Technology Data Exchange (ETDEWEB)

    Dooling, J. C.; Lumpkin, A. H.

    2017-06-25

    We report recent pulse-duration measurements of the APS PC Gun drive laser at both second harmonic and fourth harmonic wavelengths. The drive laser is a Nd:Glass-based chirped pulsed amplifier (CPA) operating at an IR wavelength of 1053 nm, twice frequency-doubled to obtain UV output for the gun. A Hamamatsu C5680 streak camera and an M5675 synchroscan unit are used for these measurements; the synchroscan unit is tuned to 119 MHz, the 24th subharmonic of the linac s-band operating frequency. Calibration is accomplished both electronically and optically. Electronic calibration utilizes a programmable delay line in the 119 MHz rf path. The optical delay uses an etalon with known spacing between reflecting surfaces and is coated for the visible, SH wavelength. IR pulse duration is monitored with an autocorrelator. Fitting the streak camera image projected profiles with Gaussians, UV rms pulse durations are found to vary from 2.1 ps to 3.5 ps as the IR varies from 2.2 ps to 5.2 ps.

  16. Piercing of Consciousness as a Threshold-Crossing Operation.

    Science.gov (United States)

    Kang, Yul H R; Petzschner, Frederike H; Wolpert, Daniel M; Shadlen, Michael N

    2017-08-07

    Many decisions arise through an accumulation of evidence to a terminating threshold. The process, termed bounded evidence accumulation (or drift diffusion), provides a unified account of decision speed and accuracy, and it is supported by neurophysiology in human and animal models. In many situations, a decision maker may not communicate a decision immediately and yet feel that at some point she had made up her mind. We hypothesized that this occurs when an accumulation of evidence reaches a termination threshold, registered, subjectively, as an "aha" moment. We asked human participants to make perceptual decisions about the net direction of dynamic random dot motion. The difficulty and viewing duration were controlled by the experimenter. After indicating their choice, participants adjusted the setting of a clock to the moment they felt they had reached a decision. The subjective decision times (tSDs) were faster on trials with stronger (easier) motion, and they were well fit by a bounded drift-diffusion model. The fits to the tSDs alone furnished parameters that fully predicted the choices (accuracy) of four of the five participants. The quality of the prediction provides compelling evidence that these subjective reports correspond to the terminating process of a decision rather than a post hoc inference or arbitrary report. Thus, conscious awareness of having reached a decision appears to arise when the brain's representation of accumulated evidence reaches a threshold or bound. We propose that such a mechanism might play a more widespread role in the "piercing of consciousness" by non-conscious thought processes. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Self-Pierce Riveting Through 3 Sheet Metal Combinations

    Science.gov (United States)

    Andersson, Roger; Jonason, Paul; Pettersson, Tommy

    2011-05-01

    One way to reduce the CO2 emissions in automotives is to reduce the weight of the Body-In-White. One easy to achieve the weight reduction is to replace steel sheet materials with Al alloys, which is 3 times lighter. One issue is the joining process, especially with combinations between steel grades and AL alloys. Example of combination of mixed material combinations (Al-steel) might be found in the door structure. The reason is because of the AL alloys worthier crash performance so the automotive manufacturer might want to use crash impact beams made by high strength steels in a AL intensive door structure. The joining process between aluminum and steel are problematic due it's not possible to use traditional spot-welding technologies due to the materials total difference in microstructure characteristics as well thermal properties. To overcome this issue then mechanical as well adhesion joining are frequently used. This paper describes a development process and subsequently analysis of a self-pierce rivet (SPR) process between 3 sheet metal combinations. The multi-material combinations in this study were a combination of ultra high strength steels sheets (DP1000) and a Al-alloy (AA 6014). The analysis of the SPR process, in sense of mechanical strengths, has been done by peel- and shear tests. To reduce the amount of future physical tests a virtual FE-model has been developed for the process. This FE model of the process has been subsequently used to analyze the mechanical strength during plastic deformation. By using inverse analysis a correct contact algorithm has been evaluated that would predict the binding force between the rivet and sheet under a deformation process. With this new virtual model it will not only possible to analyze and develop the SPR process but also to achieve the final strength of the joint.

  18. The Adhesion and Formation Mechanism of Blast Furnace Gunning Layer

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Basing on the study of the equilibrium relationship of interfacial tension among gunning particles, repaired surface and atmosphere, this test is in a position to draw a conclusion concerning the adhesion mechanism of the gunning refractory and the repaired surface, which illustrates the formation of the bottom gunning layer by moist fine gunning particles on the repaired surface. Also involved within the scope of discussion and probe are the patterns formed under this contacting effect and the formation mechanism of gunning layer. The analytic research regarding the behavior of gunning interface has ascribed the influence upon adhesion intensity to the quality of furnace gunning refractory, the state of the repaired surface and the gunning techniques.

  19. Mole guns in Turkey in 2003-2005.

    Science.gov (United States)

    Yilmaz, Riza; Birincioğlu, Ismail; Cakir, Ismail; Uner, H Bülent; Açikgöz, Dinç; Seçkin, Cetin

    2007-01-01

    This study describes the frequency of mole guns in Turkey by examining the cases sent to the Council of Forensic Medicine of Turkey between 2003 and 2005. In total, 11 mole guns were examined. Mole guns are manufactured to be used as a trap against detrimental animals. Although they are not meant to be used as a firearm, they are able to cause death. Mole guns appearing in regular casework were evaluated in terms of type of the gun, number of barrels, size and caliber, rifling, design, mechanism, fitness for use, legality, and geographical distribution. Ninety-one percent of the guns were 12 gauge. Most commonly they originate from Inner Anatolia. Mole guns are typically handmade. Some examples of injuries and deaths caused by mole guns are also offered.

  20. Electron cooling device without bending magnets

    Science.gov (United States)

    Sharapa, A. N.; Shemyakin, A. V.

    1993-11-01

    The scheme of an axisymmetric electron cooling device without bending magnets is proposed. Solutions for the most important elements, i.e., a gun and a recuperator, are considered. The main characteristics of the recuperator of the Faraday cup type having a reflector and a gun with a ring emitter are explored. In the gun, the beam is formed, the diameter of which is 40 mm and the dimension of a disturbance region is several millimeters.

  1. The Real Costs of Gun Violence

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Philip J. (Duke University)

    2001-03-14

    I will report some of the results in my new book, 'Gun Violence: The Real Costs' (Oxford University Press, 2000; with Jens Ludwig). The problem of gun violence is usually summarized by statistics on deaths and injuries. Those statistics tell only part of the story. All of us bear some of the burden of gun violence, at least in the form of higher taxes and waiting to go through the airport security checks. But that's just the beginning. The extraordinary reductions in lethal violence that occurred during the 1990s help account for rising property values and urban renewal; further reductions are possible and would do still more to enhance the average standard of living. This talk will explain why the economic perspective provides a fresh, useful point of view on violence, and will discuss the technique used to arrive at an estimate of the magnitude of the burden.

  2. On the evaluation of Pierce parameters C and Q in a traveling wave tube

    Science.gov (United States)

    Simon, D. H.; Wong, P.; Chernin, D.; Lau, Y. Y.; Hoff, B.; Zhang, P.; Dong, C. F.; Gilgenbach, R. M.

    2017-03-01

    A study of an exactly solvable model of a traveling wave tube (TWT) shows that Pierce gain parameter C and space charge parameter Q generally depend on wavenumber k in addition to frequency ω. The choice of k at which C and Q are evaluated may strongly affect their values and, consequently, the values of the small signal gain obtained from 3- and 4-wave Pierce theory. In order to illustrate this effect, we calculate the spatial amplification rate, ki, from the exact dispersion relation for a dielectric TWT model which is exactly solvable. We compare this exact value of ki with approximate values obtained from Pierce's classical 3-wave and 4-wave dispersion relations, obtained by making various assumptions on k in the evaluation of C and Q. We find that the various ways to approximate C and Q will have a significant influence on the numerical values of ki. For our dielectric TWT example, Pierce's 4-wave TWT dispersion relation generally yields the most accurate values of ki if Q is evaluated for k = ω/v0, where v0 is the beam velocity, and if the complete frequency and wavelength dependence of C is retained. Pierce's 3-wave theory also yields accurate values of ki using a different form of Q from the 4-wave theory. The implications of this result for TWT design are explored.

  3. Dynamic Simulation of the Tank Gun Recoil Response

    Institute of Scientific and Technical Information of China (English)

    XING Jun-wen; WANG Liang-xi; SHI Yan; CHEN Chun-liang

    2005-01-01

    By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle's velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.

  4. Design of an electronically tunable millimeter wave Gyrotron Backward Wave Oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M.

    1987-01-01

    A non-linear self-consistent computer simulation code is used to analyze the saturated output of the Gyrotron Backward Wave Oscillator (Gyro BWO) which can be used as a tunable driver for a 250 GHz FEL amplifier. Simulations show that the Gyrotron BWO using a Pierce/Wiggler gun configuration can produce at least 10 kW of microwave power over the range 249 GHz to 265 GHz by varying beam voltage alone.

  5. Design of an electronically tunable millimeter wave Gyrotron Backward Wave Oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M.

    1987-01-01

    A non-linear self-consistent computer simulation code is used to analyze the saturated output of the Gyrotron Backward Wave Oscillator (Gyro BWO) which can be used as a tunable driver for a 250 GHz FEL amplifier. Simulations show that the Gyrotron BWO using a Pierce/Wiggler gun configuration can produce at least 10 kW of microwave power over the range 249 GHz to 265 GHz by varying beam voltage alone.

  6. Guns N’ Arenas黑枪事件

    Institute of Scientific and Technical Information of China (English)

    狄艾

    2010-01-01

    奇才队"零号探员"阿里纳斯(Gilbert Arenas)和知名摇滚乐团"枪和玫瑰(Guns N’Roses)"同样发迹于美国加州,但当"枪和阿里纳斯(Guns N’Are nas)"连结在一起时,代志就大条了!先前名气直逼摇滚巨星的阿里纳斯,恐怕将因去年12月的"黑枪事件"身败名裂!

  7. OCULAR INJURIES CAUSED BY BB GUN

    Directory of Open Access Journals (Sweden)

    M.S. Farahvash

    1999-08-01

    Full Text Available in ordere to determine the prognosis of perforating eye injuries caused hy BB guns in our patients, the"nvisual and anatomic results of 14 patients with gun injuries seen between September 1996 and February 1998 in Farafti Hospital and private office in Tehran were reviewed. Five patients liad nonn erf orating eye injuries. All perforated eyes underwent scleral buckling, tenseclomy, vitrectomy ami silicone injection. All injured iyes had a visual acuity of light perception or better at presentation. Among 9 cases of perforating injuries. 7 had doable and 2 had single perforation. All patients had a final.

  8. 78 FR 11902 - Review of Gun Safety Technologies

    Science.gov (United States)

    2013-02-20

    ... of Justice Programs Review of Gun Safety Technologies AGENCY: National Institute of Justice, JPO, DOJ...) is conducting a review of existing and emerging gun safety technologies and plans to issue a report... to help inform its technology assessment and market research of existing and emerging gun...

  9. Gun Violence and Children: Factors Related To Exposure and Trauma.

    Science.gov (United States)

    Slovak, Karen

    2002-01-01

    Study investigated relationship between access to firearms and parental monitoring on rural youths' exposure to gun violence, and examined the effect of gun violence exposure on mental health. Results indicated a substantial number were exposed to gun violence. Exposure was related to firearm access and parental monitoring. Implications for social…

  10. Frequency of Guns in the Households of High School Seniors

    Science.gov (United States)

    Coker, Ann L.; Bush, Heather M.; Follingstad, Diane R.; Brancato, Candace J.

    2017-01-01

    Background: In 2013, President Obama lifted the federal ban on gun violence research. The current study provides one of the first reports to estimate household gun ownership as reported by youth. Methods: In this cohort study of 3,006 high school seniors from 24 schools, we examined the frequency of household guns ownership. Results: About 65%…

  11. Should Gun Safety Be Taught in Schools? Perspectives of Teachers

    Science.gov (United States)

    Obeng, Cecilia

    2010-01-01

    Background: Gun-related injuries and deaths among children occur at disproportionately high rates in the United States. Children who live in homes with guns are the most likely victims. This study describes teachers' views on whether gun safety should be taught to children in the preschool and elementary years. Methods: A total of 150 survey…

  12. Frequency of Guns in the Households of High School Seniors

    Science.gov (United States)

    Coker, Ann L.; Bush, Heather M.; Follingstad, Diane R.; Brancato, Candace J.

    2017-01-01

    Background: In 2013, President Obama lifted the federal ban on gun violence research. The current study provides one of the first reports to estimate household gun ownership as reported by youth. Methods: In this cohort study of 3,006 high school seniors from 24 schools, we examined the frequency of household guns ownership. Results: About 65%…

  13. Should Gun Safety Be Taught in Schools? Perspectives of Teachers

    Science.gov (United States)

    Obeng, Cecilia

    2010-01-01

    Background: Gun-related injuries and deaths among children occur at disproportionately high rates in the United States. Children who live in homes with guns are the most likely victims. This study describes teachers' views on whether gun safety should be taught to children in the preschool and elementary years. Methods: A total of 150 survey…

  14. Demand Analysis of Informational Shipboard Gun Weapon System Interface Design

    Directory of Open Access Journals (Sweden)

    WANG Hui-chuan

    2013-04-01

    Full Text Available According to development demand of informational shipboard gun weapon system, design concept of shipboard gun weapon system interface is proposed. System composition is put forward and function demand of interface is analyzed from combat, training and detection aspects. General principle need to be followed in design process. A new concept is provided for development of shipboard gun weapon system interface.

  15. Repetitive Bunches from RF-Photo Gun Radiate Coherently

    CERN Document Server

    Van der Geer, C A J; Van der Geer, S B

    2004-01-01

    We consider to feed the laser wake field accelerator of the alpha-X project by a train of low charge pancake electron bunches to reduce undesired expansion due to space-charge forces. To this purpose the photo excitation laser of the rf-injector is split into a train of sub-pulses, such that each of the produced electron bunches falls into a successive ponderomotive well of the plasma accelerator. This way the total accelerated charge is not reduced. The repetitive photo gun can be tested, at low energy, by connecting it directly to the undulator and monitoring the radiation. The assertions are based on the results of new GPT simulations.

  16. Fatigue Behaviors of Self-Piercing Rivets Joining Similar and Dissimilar Sheet Metals

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2007-01-01

    This paper summarizes the fatigue test results of self-piercing rivet (SPR) joints between similar and dissimilar sheet metals. The influences of material grades, material thickness, piercing direction and the use of structural adhesive on the rivet samples’ fatigue behaviors were investigated. Fatigue test results indicate that SPR joints have superior fatigue strength than resistance spot weld (RSW) joints for the same material combinations. The application of structure adhesive also significantly enhances the fatigue strength of the joint samples; this is particularly true for the lap shear loading configuration. In addition, different piercing directions for SPR joints have a noticeable effect on the static and fatigue strength of the joints. The joint fatigue results presented in this paper can offer design engineers with the durability data for SPR joints with these material combinations. Moreover, it will provide manufacturing engineers with some insights on the effects of different manufacturing parameters on the strength and durability of these joints.

  17. Performance of nursing auxiliaries and technicians in managing piercing cutting material: a necessary study.

    Science.gov (United States)

    Moura, Elaine Cristina Carvalho; Moreira, Maria de Fátima Santana; da Fonseca, Soraia Martins

    2009-01-01

    This study aimed to analyze the knowledge of nursing auxiliaries and technicians in handling and disposing of piercing-cutting material and describe their performance. This qualitative-descriptive research was carried out with three nursing auxiliaries and 12 technicians at a medium-size hospital, totaling 15 participants interviewed through a semi-structured script. Discourse was analyzed through the content analysis technique. Results appoint that, even though the participants have theoretical knowledge on the management of piercing-cutting material, they do not totally follow their knowledge, which exposes them to several biological risks, revealing reproductive knowledge and performance. Thus, we propose the implementation of continuing education programs based on constructivist methodological approach aiming at effective practices in the management and disposal of piercing-cutting material. In this perspective, research clarifying how adults apprehend knowledge can deepen the results described in the study.

  18. Experimental results of an rf gun and the generation of a multibunch beam

    Directory of Open Access Journals (Sweden)

    Abhay Deshpande

    2011-06-01

    Full Text Available At the laser undulator compact x-ray source at KEK, our group has designed and built a new rf gun with a larger mode separation of 8.6 MHz and higher Q value than earlier guns. This paper presents details on the design and fabrication, low-power measurements, and tuning procedures followed in the fabrication of the gun cavity. We also give a detailed account of experiments performed with this gun and present measurement results. We have successfully generated 100 bunches per train with a 50 nC charge at 41 MeV and 300 bunches per train with a 160 nC charge at 5 MeV, with low peak-to-peak energy difference. In the future, we plan to go up to a 0.5 nC charge per bunch in an 8000-bunch train at low energy and a 2 nC charge per bunch in a 100-bunch train at high energy. This will make it possible to have higher charge available for laser-beam collisions, thus enabling the generation of high flux soft x rays using the low-energy electron beam and approximately 30 keV x rays using the high-energy electron beam.

  19. Online visual inspection of self-piercing riveting to determine the quality of the mechanical interlock

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, P; Cullen, J D; Al-Shamma' a, A I; Shaw, A [Liverpool John Moores University General Engineering Research Institute, RF and Microwave Group, Byrom Street, Liverpool, L3 3AF (United Kingdom)

    2007-07-15

    Self-piercing riveting (SPR) has become a significant joining technique for the automotive applications of aluminium sheets. Quality control in this locale has progressed at an altogether more leisurely rate than other areas of mechanical joining (e.g. spotweld) and is underdeveloped. Testing the quality mechanical interlock is often achieved by destructive testing, which results in material and time wastage. The solution is online monitoring of the self-piercing riveting process to provide non-destructive testing of the mechanical interlock. Introducing sensors into the process facilitates real time data acquisition, which can be used to determine the quality of the joint.

  20. 3D finite elements method (FEM Analysis of basic process parameters in rotary piercing mill

    Directory of Open Access Journals (Sweden)

    Z. Pater

    2012-10-01

    Full Text Available In this paper 3D FEM analysis of process parameters and its infl uence in rotary piercing mill is presented. The FEM analyze of the rotary piercing process was made under the conditions of 3D state of strain with taking into consideration the thermal phenomena. The calculations were made with application of different rolls’ skew angles and different plug designs. In the result, progression of shapes, temperature and distributions of stress and strain were characterized. The numerical results of calculations were compared with results of stand test with use of 100Cr6 steel. The comparisons of numerical and experimental tests confirm good agreement between obtained results.

  1. Fired Models of Air-gun Source and Its Application

    Institute of Scientific and Technical Information of China (English)

    Luo Guichun; Ge Hongkui; Wang Baoshan; Hu Ping; Mu Hongwang; Chen Yong

    2008-01-01

    Air-gun is an important active seismic source. With the development of the theory about air-gun array, the technique for air-gun array design becomes mature and is widely used in petroleum exploration and geophysics. In order to adapt it to different research domains,different combination and fired models are needed. At the present time, there are two firedmodels of air-gun source, namely, reinforced initial pulse and reinforced first bubble pulse.The fired time, space between single guns, frequency and resolution of the two models are different. This comparison can supply the basis for its extensive application.

  2. Grip-Pattern Recognition for Smart Guns

    NARCIS (Netherlands)

    Kauffman, J.A.; Bazen, A.M.; Gerez, S.H.; Veldhuis, R.N.J.

    2003-01-01

    This paper describes the design, implementation and evaluation of a user-verification system for a smart gun, which is based on grip-pattern recognition. An existing pressure sensor consisting of an array of 44 x 44 piezoresistive elements has been used. An interface has been developed to acquire pr

  3. 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.

  4. Green plasticizers for multibase gun propellants (Lecture)

    NARCIS (Netherlands)

    Schoolderman, C.; Driel, C.A. van; Zebregs, M.

    2007-01-01

    TNO Defence, Security and Safety has a long history of research on gun propellants. Areas investigated are formulating (new ingredients, optimization), manufacturing, charge design and lifetime assessment [1,2,3,4,5]. In conventional propellants inert plasticizers are used to alter performance,

  5. Gas powered fluid gun with recoil mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Grubelich, Mark C.; Yonas, Gerold

    2017-01-03

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided by a cavitating venturi 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.

  6. Guns on Campus: A Chilling Effect

    Science.gov (United States)

    Mash, Kenneth M.

    2013-01-01

    The author of this article observes that, while much has been written on the overall topic of safety with regard to allowing guns on college campuses, little has been said about how allowing the possession of deadly weapons can create a "chilling effect" on academic discussions. This article considers how some universities have…

  7. Factors affecting penetrating captive bolt gun performance.

    Science.gov (United States)

    Gibson, Troy J; Mason, Charles W; Spence, Jade Y; Barker, Heather; Gregory, Neville G

    2015-01-01

    Captive bolt stunning is used for rendering livestock insensible at slaughter. The mechanical factors relating to performance of 6 penetrating captive bolt gun (CBG) models were examined. The Matador Super Sécurit 3000 and the .25 Cash Euro Stunner had the highest kinetic energy values (443 J and 412 J, respectively) of the CBGs tested. Ninety percent (27/30) of CBGs held at a government gun repository (United Kingdom) were found to have performed at a normal standard for the model, while 53% (10/19) of commercial contractor CBGs tested were found to underperform for the gun model. When the .22 Cash Special was fired 500 times at 4 shots per min, the gun reached a peak temperature of 88.8°C after 2.05 hr. Repeat firing during extended periods significantly reduced the performance of the CBG. When deciding on the appropriate CBG/cartridge combination, the kinetic energy delivered to the head of the nonhuman animal, bolt penetration depth, and species/animal type must be considered. It is recommended that CBGs are routinely checked for wear to the bolt and barrel if they are repeatedly fired in a session.

  8. Magnetic guns with cylindrical permanent magnets

    DEFF Research Database (Denmark)

    Vokoun, David; Beleggia, Marco; Heller, Luděk

    2012-01-01

    The motion of a cylindrical permanent magnet (projectile) inside a tubular permanent magnet, with both magnets magnetized axially, illustrates nicely the physical principles behind the operation of magnetic guns. The force acting upon the projectile is expressed semi-analytically as derivative...

  9. Issue Management and the Australian Gun Debate.

    Science.gov (United States)

    Reynolds, Christopher

    1997-01-01

    Examines the rise and fall of media coverage of the issues of gun control and political conflict in Australia after an incident of mass murder in April 1996. Aims to reveal the issue management process that occurred and the hidden agendas that motivated the political and media activity. Demonstrates the media's role in the creation of issue…

  10. Green plasticizers for multibase gun propellants (Lecture)

    NARCIS (Netherlands)

    Schoolderman, C.; Driel, C.A. van; Zebregs, M.

    2007-01-01

    TNO Defence, Security and Safety has a long history of research on gun propellants. Areas investigated are formulating (new ingredients, optimization), manufacturing, charge design and lifetime assessment [1,2,3,4,5]. In conventional propellants inert plasticizers are used to alter performance, proc

  11. Guns on Campus: A Chilling Effect

    Science.gov (United States)

    Mash, Kenneth M.

    2013-01-01

    The author of this article observes that, while much has been written on the overall topic of safety with regard to allowing guns on college campuses, little has been said about how allowing the possession of deadly weapons can create a "chilling effect" on academic discussions. This article considers how some universities have…

  12. Nerf Guns Strike a Nerve on Campuses

    Science.gov (United States)

    Young, Jeffrey R.

    2008-01-01

    Killing zombies on campus just isn't as much fun as it used to be. Students at Bowling Green State University once carried Nerf guns for a week each semester, shooting the zombies before the creatures could tag them. Participants were seen by most bystanders as nerdy but harmless kids who liked role-playing. These days, bright plastic Nerf guns…

  13. Cerebral damage caused by nail gun injury

    Directory of Open Access Journals (Sweden)

    Andersen Chris Hedeman

    2016-06-01

    Full Text Available 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-inflicted or a criminal act.

  14. Safety Plan for Schools: No Guns

    Science.gov (United States)

    Shah, Nirvi

    2013-01-01

    In a pre-emptive move against a school safety proposal from the National Rifle Association that is expected to include a call for more people trained and approved to carry guns at schools, a coalition of civil rights and education groups unveiled its own safety plan last week. It seeks the creation of positive school climates, thoughtful and…

  15. How Sociology Texts Address Gun Control

    Science.gov (United States)

    Tonso, William R.

    2004-01-01

    William R. Tonso has chosen an issue that he knows something about to examine how sociology textbooks address controversy. Appealing for gun control is fashionable, but it is at odds with a fondness that ordinary Americans have for their firearms--one that is supported by a growing body of research on deterrence to crime. There are two sides to…

  16. Capital Punishment, Gun Ownership, and Homicide.

    Science.gov (United States)

    Kleck, Gary

    1979-01-01

    Examines two controversial questions related to the problem of interpersonal violence in America: (1) Does use of the death penalty exert any measurable influence on the rate of homicide in the United States? (2) What relationship, if any, exists between the level of gun ownership and the level of homicide violence? (Author)

  17. 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.

  18. Prebunched-beam free electron maser

    Science.gov (United States)

    Arbel, M.; Ben-Chaim, D.; Cohen, M.; Draznin, M.; Eichenbaum, A.; Gover, Abraham; Kleinman, H.; Kugel, A.; Pinhasi, Yosef; Witman, S.; Yakover, Y. M.

    1994-05-01

    The development status of a prebunched FEM is described. We are developing a 70 KeV FEM to allow high gain wideband operation and to enable variation of the degree of prebunching. We intend to investigate its operation as an amplifier and as an oscillator. Effects of prebunching, frequency variation, linear and nonlinear effects, will be investigated. The prebuncher consists of a Pierce e-gun followed by a beam modulating section. The prebunched beam is accelerated to 70 KeV and injected into a planar wiggler containing a waveguide. The results obtained to date will be presented. These include: characterization of the e-gun, e-beam transport to and through the wiggler, use of field modifying permanent magnets near the entrance and along the wiggler to obtain good e-beam transport through the wiggler, waveguide selection and characterization.

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

    Science.gov (United States)

    Paramonov, V.; Philipp, S.; Rybakov, I.; Skassyrskaya, A.; Stephan, F.

    2017-05-01

    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.

  20. Study on Armor-piercing Power of Steel Target under the Impact of Cube-shaped Fragment%立方形破片对钢靶的穿甲威力研究

    Institute of Scientific and Technical Information of China (English)

    彭军; 袁宝慧; 程淑杰; 陈皓

    2011-01-01

    Through six shot ballistics limit law with 14. S mm ballistic gun and LS-DYNA, the ballistic limit speed of 8 g cube-shaped steel fragments and 3 g, 8 g cube-shaped tungsten-alloy fragments, vertically penetrating the Q235 steel target, is studied, and the piercing mechanism and armor-piercing power of three the types of fragmentation near the ballistic limit speed are also analyzed. The results show that the mechanism of three types of fragments is same. In the case of similar impact specific kinetic energy, the fragment density is the main factor affecting armor-piercing power, when the fragment penetrates 5 mm steel target; but the density and quality of fragments decide the fragment armor-piercing power together when penetrating 10 mm steel target.%利用14.5 mm弹道枪通过六射弹弹道极限法,结合LS-DYNA数值计算法研究了8 g立方形钢破片和3 g、8 g立方形钨合金破片垂直侵彻Q235钢靶板的v50弹道极限速度,并分析了三种类型破片在v50弹道极限速度附近的穿甲机理、穿甲威力等.结果表明,三种破片在侵彻靶板时具有相同的穿甲机理,两种类型的钨合金破片具有良好的穿甲效果.在冲击比动能相差不大的情况下,贯穿5mm靶时,破片材料的密度是影响穿甲威力的主要因素;而贯穿10 mm靶时,破片的密度和质量共同决定着破片的穿甲威力.