Accession Number : ADA180926

Title :   Research and Development of Photon Activated Thermionic Cathodes for Excimer Lasers.

Descriptive Note : Final rept. 1 Oct 84-30 May 85,

Corporate Author : THERMO ELECTRON CORP WALTHAM MASS

Personal Author(s) : Oettinger,P. E.

Report Date : OCT 1986

Pagination or Media Count : 142

Abstract : A combined experimental and analytical study was designed to determine whether electron emission from thermally pulsed laser heated cesiated surfaces is due to thermally non-equilibrated thermionic effects, and, if so, to provide a description of the relevant physical processes and their limitations. The experiments were performed with specific pulses of laser radiation incident on tungsten surfaces immersed in a low pressure cesium vapor. The measurements indicated that thermionically generated space charge limited currents are generated, and that their magnitudes could only be accounted for by thermal nonequilibrium effects. The rapidly rising current pulses were often observed to transition into a plasma dominated flow that could be curtailed by diode charges. These experiments and conclusions are discussed in this report in more detail. Keywords: Laser heating; Diode; Thermionic emission; Nonequilibrium; Cesium tungsten.

Descriptors :   *EXCIMERS, *THERMIONIC EMISSION, *CESIUM, *METAL VAPORS, *LASER COMPONENTS, TUNGSTEN, LASERS, LASER BEAMS, ACTIVATION, CATHODES, PHOTONS, ELECTRON EMISSION, HEATING, LOW PRESSURE, VAPORS, HEAT, PULSED LASERS, SURFACES, PLASMA DEVICES, LASER PUMPING

Subject Categories : Lasers and Masers
      Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE