Performance of an electron gun
Electron gun for applying external gun to diode emitter region
EMITTER↗
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Carbon nanotube electron gun
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.
Nguyen, Cattien V.↗
Carbon Nanotube Electron Gun
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.
Nguyen, Cattien V.↗
A compact high current pulsed electron gun with subnanosecond electron pulse widths
A magnetically-collimated, double-pulsed electron gun capable of generating electron pulses with a peak instantaneous current of approximately 70 microamps and a temporal width of 0.35 ns (FWHM) has been developed. Calibration is accomplished by measuring the lifetime of the well known 2(1P)-to-1(1S) transition in helium (58.4nm) at a near-threshold electron-impact energy by use of the delayed-coincidence technique.
Khakoo, M. A.↗
Development program on a cold cathode electron gun
A prototype electron gun with a field emitter cathode capable of producing 95 mA in a 1/4 mm diameter beam at 12 kV was produced. Achievement of this goal required supporting studies in cathode fabrication, cathode performance, gun design, cathode mounting and gun fabrication. A series of empirical investigations advanced fabrication technology: More stable emitters were produced and multiple cone failure caused by chain reaction discharges were reduced. The cathode is capable of producing well over 95 mA, but a substantial collector development effort was required to demonstrate emission levels in the 100 mA region. Space charge problems made these levels difficult to achieve. Recommendations are made for future process and materials investigation. Electron gun designs were modeled and tested. A pair of two-electrode gun structures were fabricated and tested; one gun was delivered to NASA. Cathodes were pretested up to 100 mA at SRI and delivered to NASA for test in the gun structure.
Spindt, C. A.↗
The development of a multi-cathode electron gun
A multicathode electron gun, capable of automatically interchanging cathode structures of a microwave electron tube upon command was developed. This technique extends the life of a microwave electron tube into the range of fifty to one hundred years. The concept consists of mounting a number of cathode structures on a rotating platform. Rotation of the platform moves the different cathodes into operating position. The component tests, construction and operation of the gun are described.
Roberts, L. A.↗
Pulsed Electron Gun
Magnetically-collimated electron gun generates electron pulses with peak instantaneous currents of approximately microA with pulse widths of approximately 0.35 ns.
Srivastava, Santosh K.↗
Performance of a Carbon Nanotube Field Emission Electron Gun
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). Performance of the CNT e-gun has been evaluated. A traditional 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.
Getty, Stephanie A.↗
An electrostatically and a magnetically confined electron gun lens system
Focal properties, electron trajectory calculations, and geometries are given for two electron 'gun' lens systems that have a variety of applications in, for example, electron-neutral and electron-ion scattering experiments. One nine-lens system utilizes only electrostatic confinement and is capable of focusing electrons onto a fixed target with extremely small divergence angles, over a range of final energies 1-790 eV. The second gun lens system is a simpler three-lens system suitable for use in a uniform, solenoidal magnetic field. While the focusing properties of such a magnetically confined lens systenm are simpler to deal with, the system does illustrate features of electron extraction and Brillouin flow that have not been suitably emphasized in the literature.
Bernius, Mark T.↗
A fast electron gun for study of atomic decays.
A fast electron gun with subnanosecond rise and decay times and 100 mA peak beam current has been developed for delayed coincidence studies of atomic decays. The gun is fabricated from an inexpensive tetrode nuvistor, only slightly modified. The electron gun system has been successfully used in a delayed concidence study of fast decays of ionized helium.
Sutton, J. F.↗
ELECTRON GUN FOR EVAPORATION OF OXIDE FILM
Electron guns for evaporation of refractory oxide film
OXIDE FILM↗
NASCAP simulation of laboratory charging tests using multiple electron guns
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.
Mandell, M. J.↗
The accuracy of numerical solutions for electron gun design.
Numerical solutions of Poisson and motion equations for electron gun design, examining truncation error via perturbation theory
MOTION EQUATION↗
A fast electron gun for study of atomic decays
A fast electron gun with subanosecond rise- and decay-times and 100 ma. peak beam current has been developed for delayed coincidence studies of atomic decays. The gun is fabricated from an inexpensive tetrode Nuvistor, involving only slight modification.
Sutton, J. F.↗
Computer experiments on electron guns.
Cathode current density distribution, beam minimum radius and location and electrode current interception, using computer techniques on electron guns
CATHODE↗
Development of a Robust, High Current, Low Power Field Emission Electron Gun for a Spaceflight Reflectron Time-of-Flight Mass Spectrometer
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 modeling results to describe the performance of a field emission electron gun as employed in the Volatile Analysis by Pyrolysis of Regolith (VAPoR) TOF-MS prototype.
Southard, Adrian E.↗
Development program on a Spindt cold-cathode electron gun
A thin film field emission cathode (TFFEC) array and a cold cathode electron gun based on the emitter were developed. A microwave tube gun that uses the thin film field emission cathode as an electron source is produced. State-of-the-art cathodes were fabricated and tested. The tip-packing density of the arrays were increased thereby increasing the cathode's current density capability. The TFFEC is based on the well known field emission effect and was conceived to exploit the advantages of that phenomenon while minimizing the difficulties associated with conventional field emission structures, e.g. limited life and high voltage requirements. Field emission follows the Fowler-Nordheim equation.
Spindt, C. A.↗
Beam transmission in electron guns having a single-apertured control grid.
Beam transmission in electron guns having single apertured control grid, studying ratio of target current to cathode current
Buritz, R. S.↗