Abstract: A scanning beam laser pumped laser is disclosed which is capable of producing pulses of 50 or more microsecond duration with a repetition rate of 100 Hz or more and an energy content per pulse of 3 joules or more. Optics focus the output beam of the pumping laser onto the front surface of the pumped laser which may comprise a flowing dye cell. A rotating mirror synchronized with the pulse repetition rate of the pumping laser moves the spot across the dye in the pumped laser in a direction preferably orthogonal to the flow of dye therein. A spherical mirror behind the rear surface of the dye cell reflects radiant energy back toward the rotating mirror. Reflective radiance is turned therefrom to, in part, pass through the aperture of a beam-combining mirror. The small fraction of radiant energy passing through either a partially reflecting surface or a small aperature on the beam combining mirror enters a resonant cavity whose dimensions define the wavelength of the pumped laser.

Abstract: Apparatus and process for isotopically selective multi-step photoionization in which the final or ionizing step is tuned to produce a specific transition to an excited state above ionization for which the ionization cross-section is substantially greater than for ionization transitions in general. The autoionization transition to an ionized state is typically made from a highly excited bound state which is reached in one or two isotopically selective energy jumps from the ground state or other low-lying levels. The isotope shift for the ionization transition is typically small compared to the bandwidth of the ionization transition and relatively broad band photoionization radiation covering the entire absorption line can be employed. Broad band radiation is more economic and is preferable for use wherever possible. A technique is also shown for identifying the ionization transitions of augmented cross-section.

Abstract: A linear electron beam evaporation source for a high vapor temperature material such as uranium, the source being provided with a filamentary emitter and apparatus for controlling the filament electron emission to maintain an approximately constant current per filament unit length. A control structure is provided and operated to create a space charge in the vicinity of the electron emitting filament such that the current density of the electron beam is controlled by the space charge rather than the local electron emissivity along the length of the filament.

Abstract: A system for applying accelerating forces to ionized particles of a vapor in a manner to suppress the flow of electron current from the vapor source. The accelerating forces are applied as an electric field in a configuration orthogonal to a magnetic field. The electric field is applied between one or more anodes in the plasma and one or more cathodes operated as electron emitting surfaces. The circuit for applying the electric field floats the cathodes with respect to the vapor source, thereby removing the vapor source from the circuit of electron flow through the plasma and suppressing the flow of electrons from the vapor source. The potential of other conducting structures contacting the plasma is controlled at or permitted to seek a level which further suppresses the flow of electron currents from the vapor source.

Abstract: A long life, high emission electron source for a plasma environment. The plasma environment is made up of corrosive particles having a lower work function than the exposed material of the electron source. The electron source is operated at an elevated temperature not only to provide free electrons but also to establish and maintain a thin partial monolayer coating of the source's emissive surface with plasma particles in an equilibrium between condensation and evaporation. The equilibrium coating increases the emissivity of the surface without permitting substantial corrosion of the surface or structure from the particles of the plasma environment. The cooler regions of the electron source are shielded from the plasma particles to prevent a build-up of corrosive particles.

Abstract: A probe for detecting the evaporation rate of an electron beam evaporation source and for monitoring induced ionization of the vapor. A negatively biased electrode responds to ions in the vapor to measure the ion current density. The ions measured may result from the process of vaporization or from laser produced isotopically selective ionization. The probe provides a current output which is detected as an indication of vaporization or laser ionization rate.