Type Of Gun Research Articles

Missile wounds caused by tear-gas pen guns.

Three cases of missile wounds caused by tear-gas pen guns, including deaths by homicide and suicide as well as an unusual accidental injury, are presented. Although recent domestic models of tear-gas pen guns, designed for self-defense, are not classified as firearms, some of the older types of pen guns, with or without modification, may accommodate either fixed metallic cartridges or shotgun shells. The features of the missile wounds and the problems related to the identification of the firearm are discussed. Consideration is given to the potential hazard of reloaded, disposable threaded cartridges of protective tear-gas devices.

Simplified Analysis of Point-Cathode Electron Sources

The accelerating field of a point-cathode electron source is divided into two regions, a diverging spherical-field region located in the immediate vicinity of the point cathode, and a converging-field region which occupies most of the cathode-anode space. Analysis of this model gives the Gaussian source size, axial position of the source, and spherical- and chromatic-aberration constants of the pointed-cathode electron gun. After including diffraction effects, the electron-optical parameters are optimized for minimum possible source size. The current density which appears to be emitted by the apparent source is introduced as a figure of merit for this type of electron gun, and the performance of field-emission and Schottky-emission pointed cathodes are compared. Source diameters below 100 Å are predicted for oriented-tungsten field-emission pointed cathodes, with apparent current densities exceeding 104 A/cm2; source diameter below 1000 Å are predicted for oriented-tungsten Schottky-emission pointed cathodes, with apparent current densities of approximately 100 A/cm2.

Space-Charge Effects by Nonthermal Ions in a Magnetized Plasma

In combination with transverse density gradients the finite Larmor radius produces space-charge effects both in the interior and at the boundaries of a magnetized plasma. In a thermal plasma having moderately large density gradients, electric quasi-neutrality can be preserved by a smoothly varying electric potential of limited amplitude. It is not obvious that a plasma containing groups of nonthermal ions will behave in a similar way when there are steep density gradients. An example is given here where a strongly oscillating potential of sheath-like structure arises from nonthermal ions which are peaked at a singular velocity. Whenever nonthermal effects of this or a similar kind occur, they should introduce fundamental changes in the plasma behavior which cannot be described by elementary plasma theory. Possible applications are given by the motion of a plasma through a neutral gas, where groups of nonthermal ions arise from charge exchange and ionizing collisions. The electric fields generated by the nonthermal particles may affect the ionization process and become connected with the mechanisms of ionizing waves and with the observed voltage limitation in rotating plasmas and in certain types of plasma guns.

A New Type of Crossed Field Electron Gun

ABSTRACTA new type of crossed field gun utilizing a tapered magnetic field in the gun region is discussed. A closed form space charge model is presented that avoids the singularity at ωcτ = 2π and allows pseudo-parabolic trajectories. The shapes of the gun electrodes are derived by analytic continuation of the space-charge potential off the beam peripheries. The possibility of obtaining high convergence, low noise, laminar beams using this type of gun is discussed.

Developments in Electrostatic Spray Painting and Fluidized Bed Coating

SummaryThe development of electrostatic paint spraying through its various forms is briefly outlined and some of the more recent developments in the application of automatic equipment as well as the latest advances which have enabled the principles of electrostatic painting to be applied to hand-operated equipment are described. Following the description of the latest types of electrostatic hand-spray paint guns, the electrostatic application of powders by means of hand-operated electrostatic equipment is discussed and, finally, recent developments in the application of resins and plastics in powder form by means of automatic equipment based on fluidized bed techniques.

Basic Measurements in a Rail Type Plasma Gun

The rail-type plasma-gun is a well suited laboratory set-up for the experimental determination of the physical properties of short lived plasmas. The ONERA plasma-gun is the most conventional rail type gun, with two cylindrical electrodes; an electrical discharge between two auxiliary electrodes generates the plasma whenever a puff of argon is injected into the plasma gun. Measurements on the set-up are devised to give the following data: - mass flow rate through the injection nozzle or amount of argon corresponding to each puff; - current and voltage during a discharge; - self induction of the rails; - shape and displacement of the plasma column (magnetic coil probe and photo-cell recordings). Though not necessarily an efficient space propulsion device, the parallel rail plasma-gun allows the development and improvement of many experimental techniques, which can be used for the study of more efficient electric thrustors.

Design of hollow and strip beam guns

This paper covers a study of strip and hollow beam guns. An automatic electron trajectory tracer has been used to study the properties of the slit-anode lens common to these types of guns. A thin beam approximation was made so that a flat-bottom electrolytic tank could be used. The results of this study have been incorporated into gun design charts. Eight hollow beam guns have been built and tested experimentally. The experimental data of these guns compare favorably with the data obtained from the anode-lens study. The limitation of thermal velocities on the maximum area compression of strip and hollow beam guns is discussed. The experimental results of a focusing scheme which uses a uniform magnetic field to focus a hollow beam down concentric drift tubes are discussed.

The initial disturbances affecting the direction of trajectory of a shot fired from a high-velocity gun

The object of the investigation was to determine, both theoretically and practically, the effect on the subsequent shot motion of the initial interactions between a high-velocity gun, its mounting, the gas discharge from the muzzle and the shot, in order to evaluate the unknown relative magnitudes of various causes of trajectory inconsistency, with a view to reducing such inconsistency in both existing and later designs of similar weapons. In the investigation theoretical considerations are compared with measurements made during an extensive experimental programme. This began with a study of the lateral muzzle movements of two gun types (6 and 17 pounders) by means of a novel optical-lever method which eliminates shock disturbances. The recorded movements were found to disagree with those calculated on an existing elastic theory based on a simplified model of the dynamical system, but during the course of the work a more elaborate model was shown to give some measure of agreement for one of the gun types. The measured muzzle displacement at shot ejection in general did not represent the major direct contribution to the 'jump’ recorded on the target. To determine the relative importance of other contributory causes the programme was extended to measurements of the yaw oscillations of the shot when travelling down the bore and through the post-ejection blast zone, these being achieved by means of a novel method in which a mirror was positioned on the nose of the shot, supplemented by X-ray flash photography in the blast zone and jump card observations just outside the blast zone. The work has enabled the major contributions to gun and projectile inaccuracies in the systems tested to be evaluated and explained, and indicates general principles for their improvement.

Studies of Melting by 60kW Electron Beam Furnace.

Some design features of a 60 kW remote controllable gun type electron beam furnace are described.Distance between the target crucible and the cathode was about 1.3 meter. This rather long distance prevents apparently contamination from the cathode materials by evaporation of sputtering. After 150 hrs of melting the cathode seemed slightly to be eroded by ionic bombardment but it could be put into further service.Various forms of tanalum, tungsten, and other refractory metals were melted satisfactorily by using the furnace.Optimization of operating variables for melting tantalum was also studied.

Characteristics of a point cathode triode electron gun

An investigation has been carried out into the behaviour of the system obtained when a small pointed cathode is applied in a triode electron gun. The dependence of the gun current, brightness, source position and other important properties upon the geometrical and electrical parameters of the gun is reported, and some conclusions are drawn about the mechanism of beam formation. In particular it is shown that no appreciable field-enhancement of the emission occurs in this type of gun.

Acceleration of Plasma by a Magnetic Field

We performed the experiments on the plasma accelerators of two types. One is a rail type plasma gun and another is a travelling magnetic wave accelerator. In the former type, the plasma is accelerated by Lorentz force of the electric current and in the later type, the magnetic, piston which travels along the electric delay line acts as the drivings force. In both we measured the electric current, the velocity of plasma, some propagation characteristics, electron temperature and ion density by using a coaxial shunt, a streak camera, a Faraday cell camera, a photo-multiplier and floating double probes.The maximum velocity of plasma was 5 × 106cm/sec for, a rod-rail type gun, 5.8 × 106cm/sec for a half-cylindrical rail type gun and 10 × 106cm/sec for the magnetic piston type. One of the important conditions for the acceleration was the distribution of the magnetic field. It was improved by varying the types of rails of the plasma gun and by changing the design of delay line on the magnetic piston type. The ion density of accelerated plasma bundle was about 108cm-3. The experiment on injection of plasma to the magnetic bottle and the ion density measurement by resonance probes are now going on.

Some experiments with a new type of crossed-field gun

The construction and testing of a crossed-field gun based on an exact space-charge flow solution will be described. All the characteristic parameters of a gun of this type may be obtained analytically. Experimentally the gun was found to perform essentially as predicted. This gun has a moderately high convergence and produces a beam whose gross features give a very good approximation to planar Brillouin flow. Work by Anderson has indicated that crossed-field beams produced by a gun of this type may be somewhat less noisy than similar beams produced by other types of guns.

Focus reflex modulation of electron guns

High resolution and low drive features have been successfully combined in a new type of electron gun for cathode-ray tubes. The gun has a spot-defining aperture of 0.007 inch upon which emission from a large cathode area is concentrated by a retarding electron lens. This unit modulates the beam by electron reflection, while focusing it upon the aperture ("Focus Reflex Modulation"). Immediately ahead of the aperture, a modulated virtual cathode is formed with an emission capability of over four amperes per square centimeter. A <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1000-\micro</tex> a beam with a 6° divergence is controlled by a signal of 12 volts centered at ground potential. Highlight brigntness of 250 foot lamberts was read at 17,500 volts, while more than 500 lines were resolved on a television test pattern. In more recent forms of the FRM gun, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1600 \micro</tex> a are measured in the screen return, out of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1800-\micro</tex> a cathode current. This is 88 per cent over-all transmission, using the same defining aperture (0.007 inch). 18 volts of drive signal will completely modulate the above current.

Analysis of Spot Size Formation in Bipotential Electron Guns†

ABSTRACT A so mi-empirical method is worked out which permits prediction of the final spot size on the viewing screen of triode typo electron guns with conventional grid aperture sizes of 0.025 to 0.035 in. diameter. By basing all relations on total beam current and standard grid aperture size, the deadlock encountered in more rigorous methods, requiring gun characteristics and current distribution in the beam, is eliminated. Spot enlarging factors, such as spherical aberration and space charge, are related to the paraxial imaging laws over empirical functions, enabling one to single out each of the three components before scalar synthesis. By acquiring insight into the essential size-contributing factors of a gun, a certain amount of optimization of constructional and operational nature can be also derived. Very good agreement with spot size measurements on conventional type guns is obtained, proving the general usefulness of the method in this complex matter.

New types of crossed field electron guns

A new analytical method of designing M-type crossed field electron guns will be described. These guns are based upon an exact space charge flow solution obtained a number of years ago by Pembank, Brillouin and others. The actual design procedure is essentially the same as for Pierce Guns, and the precise electrode shapes are obtained by a method of conformal mapping and a subsequent numerical calculation. Two types of guns result from this procedure. The first, somewhat similar to the French has been constructed and extensively studied. This gun is characterized by an almost complete absence of sole current. Approximate expressions relating current, voltage and magnetic field have been derived for this gun and experimental values are within a few percent of these calculations. Visual observations indicate the shape of the beam in the gun to be essentially as predicted by theory. A convergence of approximately 7:1 has been obtained with this gun. A second type of gun, based on an approximation to the exact flow solution is possible. This gun is characterized by an extremely high convergence and operates at a somewhat higher magnetic field than the short gun. A gun of this type has been constructed and appears to give a fairly well defined beam with approximately the predicted current.

Gunshot wounds of the chest in civilian practice.

Many excellent reports have been published concerning the care of thoracic wounds during World War II and the Korean conflict, but little has appeared recently about civilian wounds. It is the purpose of this paper to set forth the system by which gunshot wounds of the chest are handled at the Marion County General Hospital and to indicate what results may be anticipated. Material During the period 1948-1957, 83 cases of gunshot wound of the chest were treated on the surgical service of the Marion County General Hospital. These cases do not include patients who were dead on arrival or patients who died soon after admission to the emergency ward and were, therefore, never admitted to the surgical service. The cause of wounding was a fight in 31 cases, an attempted suicide in 25, a police action in 19, and an accident in 8. The type of gun was.22 caliber

A design method for crossed-field electron guns

A design method for crossed-field guns based on a space-charge-flow solution in crossed fields is given. By using the method of analytic continuation in the complex plane, it is shown that it is possible to find the exact form of the electrodes required The design results in a gun similar to the French "short gun" with the great advantage that the current emitted from the gun and the current density at the cathode can be predicted. It is also shown that by making certain approximations to the exact space-charge-flow solution, a new type of gun can be designed, a "long gun" which can have extremely high convergence. The theory for this latter gun is extremely simple and the electrode shapes can be given entirely in analytic form.

High transconductance wide-band cathode-ray gun

The “screen-grid amplifier gun” is a combination of a conventional tetrode-type gun with an amplifier constituted in large measure by the gun's existing electrodes. In its simplest version the gun has, in fact, only one electrode more than conventional guns. The new gun has three grids participating in the beam mod ulation process: an auxiliary input grid and the two grids of the immersion lens. These latter grids are coupled together and operated 180° out of phase with respect to the input grid. Transconductance and resolution have been divorced from each other to a large extent in the screen grid amplifier gun. The low shunt capacitance makes the gun particularly suitable for wideband operation. Favourable possibilities are offered by this development for building guns with smaller “gamma” than hitherto possible. Analytical expressions correlating the gun's beam current to various types of gun drive, namely, combined screen and control grid drive, control grid drive and cathode drive are derived for cathode-ray guns of conventional design. An analytical expression for the gun's modulation constant is also given. Television guns possessing excellent resolution characteristics and transconductance in excess of 500 μmhos may be obtained rather simply. High transconductance guns and structures are shown.

The electron optics of high-current-density electrostatic electron guns

It is shown that for some types of electron gun of perveance about 2×10?6amp/volt3/2 the cathode current density can be closely determined with the aid of trajectories found in the absence of space charge. Subsequent recomputation of the trajectories allowing for space-charge forces has little effect on the emission current density previously determined. Calculations have been made on two electron guns with the aid of electrolytic-tank measurements and an automatic electron-trajectory tracer. Satisfactory agreement with experimental results is obtained.

Electronic vehicle control for traffic accident problem

During the period from about 1930 to 1950, relatively advanced gun designs were developed for black-and-white television cathode ray tubes (CRTs). However, these were not entirely satisfactory for use in the new shadow-mask color tubes introduced around 1950. Because of the need to use guns with a limited diameter, both the brightness and the resolution of these tubes were noticeably inferior to that of black-and-white tubes. It was not until almost two decades later that this problem was solved with the introduction of computer-aided design methods. This enabled small-diameter guns to be made that could perform, as well as the larger-diameter older types of guns, thus significantly increasing the brightness and resolution obtainable from color tubes. Of the various competing approaches to the high-vacuum CRT, the most successful one was developed in 1929 by Zworykin. This contained an electron gun consisting of an indirectly heated oxide cathode, a negative control grid, and an adjacent low-voltage anode maintained at several hundred volts. To converge the beam emerging from the gun, a second anode was added in the form of a conductive coating applied to the inner surface of the tube wall, extending from the phosphor screen to the low-voltage anode. By applying about 5 kV to the second anode, the beam was not only accelerated, but also focused to a small spot by the lens action created in the region between the two anodes. The superior performance of this tube, with its high brightness and small spot size, as well as its relative simplicity, was rapidly recognized and served to accelerate the introduction of black-and-white television during the next decade.