Significant progress has been made in the characterization of the necessary parameters required to create an effective Radio Frequency (RF) plasma based electron source. Such a device has the promise of comparable current densities to and longer operational lifetimes than hollow cathodes. The operational lifetime of hollow cathodes is ultimately limited by cathode deterioration. RF sources prov...

Plasma ion sources are constantly growing in importance in the field of atomic mass spectrometry. The idea is to deposit enough energy into the analyte to atomize and ionize a representative part of it and to achieve a plasma state that will endure for some period of time. A fraction of the ions can then be extracted from the plasma and analyzed in the mass spectrometer. The main difference amo...

A novel design for a dc-excited cw CO(2) metal waveguide laser has been developed in which a slotted hollow cathode also doubles as a metal waveguide for the cavity modes. This design has been implemented in a compact structure that produces over 1 W of cw 10.6-microm radiation. The discharge characteristics, laser gain, and laser output have been studied as functions of various discharge param...

Calcium aluminate electride 12CaO-7Al2O3:4e(e.g., C12A7:e-) shows promise as a low temperature electron emitter for hollow cathodes in spacecraft electric propulsion, but the material’s basic performance limits remain poorly understood, including an exact value for work function. As a supplement to a companion paper examining C12A7:eemission in a planar close-spaced diode configuration in vacuu...

Hollow cathodes are electron sources used for the gas ionization and the beam neutralization in both ion and Hall effect thrusters (HETs). A reduction of power and propellant consumption from the cathode is particularly needed in small satellite applications, where power and mass budgets are inherently limited. Concurrently, the interest in high-power HETs is increasingly fostered for a number ...

Sulfur has a high specific capacity of 1673 mAh/g as lithium battery cathodes, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a hollow carbon nanofiber-encapsulated sulfur cathode for effective trapping of polysulfides and demonstrate experimentally high specific capacity and excellent electrochemical cyc...

ABSTRACT Although T8 fluorescent lamp life is typically rated at 20,000 hours, it can significantly vary depending on the ballast product. The current industry practice for testing fluorescent lamp life requires these lamps to be subjected to 3-hours on/20-minutes off cycle, which is also known as the standard cycle for life testing. This method requires over 2 years of testing, which is expens...

Clusters of Hall thrusters are being considered for use on a variety of missions requiring electric propulsion systems capable of operating at power levels in excess of the current state of the art. One of the key factors to be considered in determining the optimum cluster architecture is the configuration of the electron-emitting cathode(s). This work presents experimentally determined plume p...