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A failure mechanism is observed for SiN2-passivated metal semiconductor field-effect transistor (MESFET) devices exposed to fast risetime DC video pulses. The intensity of the pulses is about 33% of the value required to cause single-pulse failure. The failure mechanism, which degrades performance by surface flashover and erosion of the passivation layer, eventually leads to sputtering of the gatesource metallization. The results are observed using a combination of optical, electron, and X-ray micrographs, plus MESFET terminal parameters.IEEE 1992 Microwave and Millimeter-Wave Monolithic Circuits Symposium 1

The surface motion of a gold-coated Mylar pellicle was measured interferometrically while the pellicle was subjected to bombardment from a 15-MeV, 40-mA pulsed electron beam. No surface motion as large as 0.3 microm was observed during the electron pulse. A radiation dose of 5 x 10(7) rad did not damage the surface. The results show that this foil can be used as an end mirror in free-electron-laser oscillators.

An electron beam transport experiment utilizing 5 kV electrons in a 200 mA beam passing through 36 solenoid lenses is described.The fraction of the beam transmitted is a function of the lens strengths, the length of the channel, the beam size, and the precision of the alignment. Emittance measurements in the 36-lens channel showed no significant degradation compared to a 12-lens channel.