Comparison of the performance of a high voltage generator insulated by gas or liquid dielectric.

A module of a wireless high voltage generator was tested immersed in both gaseous and liquid environments providing electrical insulation. The overall performance of the module as well as a detailed performance of the key components are reported, and a comparison between the results in gas and liquid is given. The tests performed on the liquid dielectric show that it is a valid alternative to high pressure gas electrical insulation.

Generation of microwave radiation by nonlinear interaction of a high-power, high-repetition rate, 1064 nm laser in KTiOPO4 crystals.

We report measurements of microwave (RF) generation in the centimeter band accomplished by irradiating a nonlinear KTiOPO4 crystal with a home-made, infrared laser at 1064 nm as a result of optical rectification. The laser delivers pulse trains of duration up to 1 µs. Each train consists of several high-intensity pulses at an adjustable repetition rate of approximately 4.6 GHz. The duration of the generated RF pulses is determined by that of the pulse trains. We have investigated both microwave- and second harmonic generation as a function of the laser intensity and of the orientation of the laser polarization with respect to the crystallographic axes of KTP.

A laser system for the parametric amplification of electromagnetic fields in a microwave cavity.

We describe recent improvements in the development of the high power laser system used in the motion induced radiation (MIR) experiment to amplify electromagnetic fields inside a microwave cavity. The improvements made on the oscillator stabilization, the pulse train shaping device, and the spatial beam uniformity are reported.

A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers.

We report on the design of a new type of hot-filament electron gun delivering fairly high current (a few hundreds of µ A) at high voltage (up to 100 kV) in continuous or pulsed mode. Its novel features are that the filament is heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply in order to get rid of bulky isolation transformers, and that the filament current and, hence, the electron gun current, is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. This electron gun is intended for general purposes, although we have especially developed it to meet the needs of our experiment on the infrared emission spectroscopy of rare gas excimers. Our experiment requires that the charge injection into the sample is pulsed and constant and stable in time. The new electron gun can deliver several tens of nC per pulse of electrons of energy up to 100 keV into the sample cell. The new design also eliminates ripples in the emission current and ensures up to 12 h of stable performance.