An ultraviolet radiation source associated with a suitable cathode-anode electrode structure, disposed in a gas-filled cavity of a high pressure pulsed laser, such as a transverse electric atmosphere (TEA) laser, to achieve free electron production in the gas by photoelectric interaction between ultraviolet radiation and the cathode prior to the gas-exciting cathode-to-anode electrical discharge, thereby providing volume ionization of the gas. The ultraviolet radiation is produced by a light source or by a spark discharge.
This application is a continuation of application Ser. No. 600,242, filed July 30, 1975, which in turn is a continuation of application Ser. No. 315,043, filed Dec. 14, 1972, now abandoned.
A device to provide high current, low emittance electron beams with a long life cathode. The device consists of an undulator 7 which provides a source of ultraviolet light 15 for an ultraviolet photocathode 8. The undulator 7 needs a supply of electrons to produce the ultraviolet light which it can get by diverting a portion of a beam from a linear accelerator 3 before E.sub.3 or after E.sub.4 the electron beam traverses a free electron laser 5. The device is self-maintaining once a source of electrons is developed but needs a start-up source of electrons. The start up source can be provided by a pulsed cathode electron gun 1 which has to be on for a short period of time until the ultraviolet photocathode 8 is operated. Alternatively, the start-up source can be achieved by irradiating the UV photocathode 8 by ultraviolet light from a conventional laser 9, which can be aimed through the undulator 7 and subsequently provide a seed UV laser beam at lower power to assist regeneration of the high power UV beam in the undulator. In another embodiment UV light 15 can be sent directly from the free electron laser 5 to ultraviolet photocathode 8.
An improved railgap switch for use with pulse discharge gas lasers. The blade of the prior art railgap switches is replaced by an electrode having an "T" shaped cross section which provides two edges along which arcs are generated. The thickness of the "T" cross section near the edges at which arcs are formed is relatively uniform and oriented at a constant distance from the second electrode so that the thickness and distance remains unchanged despite ablation of the edges of the electrode. As a consequence the electrical properties of the switch are not altered significantly by ablation caused by repetitive operation of the switch.
A substrate 18, a cathode 20 and an anode 22 are stored in a space demarcated by a casing 10, and the space is evacuated. The cathode 20 and the anode 22 are provided on the same surface of a substrate 18 having electric insulation, and have a comb-tooth shape so as to be mutually engaged. Therefore, the area of the part in which the cathode 20 and the anode 22 approach each other becomes larger, and thereby photoelectrons discharged from the cathode 20 through the incidence of ultraviolet rays are transmitted in the vacuum, and are favorably collected in the anode 22.
An electric discharge gas laser utilizing a seedant material which is cooled prior to the main laser discharge. The seedant is ionized prior to the cooling process and prior to the main discharge, this pre-ionization maintaining the seedant material in a gaseous state even in view of the lowered temperature for a sufficient time so as to give the required ionization levels.
A method and apparatus for constructing a continuous wave (CW) free elect laser (FEL) system capable of providing tunable high power laser radiation at short wavelengths using low-energy recirculating DC electron beams. This method replaces the static periodic magnetic field used in conventional FEL systems with an equivalently intense and continuous electromagnetic pump field having spatial periodicity less than 1 cm. The pump field is generated by a low-energy recirculated DC electron beam interacting with a transverse static periodic magnetic field.
