Cathodes capable of generating currents of 100 a to 10,000 a with current densities of 100 to 1000 a/cm2 with high brightness are required for superpower microwave, mm-wave and optical coherent radiation sources, such as free electron lasers. of presently available cathodes, only field emission type… More

A novel concept is proposed to develop coatings with dual radar and thermal suppression characteristics. the concept employs well known techniques used for radar absorbing coatings and combines them with techniques for producing low emissivity surfaces in the infrarred wavelengths in a way in which… More

High power, cw (continuous wave) sources at frequencies near 300 ghz are needed for electron cyclotron heating in advanced magnetic fusion devices such as the cit (compact ignition tokamak). recent developments in gyrotrons have pushed the state of the art to 100 kw cw at 140 ghz. one megawatt at… More

This project will examine the feasibility of depressed collectors for gyrotrons for accelerator drivers. gyrotrons are potential rf drivers for accelerators involving very high average powers, e.g., 200 mw for the 300-500 gev electron-positron collider. the efficiency of the gyrotrons will then have… More

The objective of the proposed research is to develop an acoustic monitoring device for laser lithotripsy. the acoustic monitor under consideration is a fiberoptic sensor based on a novel measurement concept. in-vitro results to date have shown considerable promise for acoustic monitoring, in… More

The new high temperature superconducting materials offer thepotential for applications aboard spacecraft because components utilizing such materials would require minimal refrigeration to operate in space. if these materials are to be used in space, it is important to determine their resistance to… More

A program is proposed to show the feasibility of depressed collectors for very high average power (approx. 1mw) gyrotron oscillators for fusion applications. initial calculations indicate that collection efficiencies exceeding 75% can be realized. use of such a colector on a gyrotron with a base… More

The proposed study will demonstrate the feasibility of using a neural network to retrieve environmental parameters such as those discussed in the 1986 joint chiefs of staff memorandum mjcs 154-86. because neural networks are inherently pattern processors, they are excellent candidates to process the… More

In order to increase efficiency, modern propulsion systems are required to operate at significantly higher temperatures than in the past. An increased heat load is therefore placed on the fuel that is used as a coolant and on the engine lubrication system. Lubricating oils are typically limited to… More