Abstract: A flexible seal permits slidable access to equipment components in an essentially zero clearance environment, without time-consuming disassembly and reassembly. A flexible seal ring includes a thickened radiused boss connected to the outer rim of a flexible flange, connected to a mounting block by an inner hub. The seal ring can be formed as a unitary structure from metal, plastic, elastomer, wood, foam, composite, or combinations thereof. Usually the seal ring has rotational symmetry. Alternatively, the seal ring has an elongated or irregular configuration, e.g. for sealing around a slot. The seal ring can contain an outer o-ring groove. The seal ring is attached to a first plate. A second plate slides laterally to align with the first plate, contacting the flexible seal surface. This presses the seal surface against the second plate, sealing the interface.

Abstract: A tangential fan for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end. The number of blade members can be constant or variable between ends. The circumferential position of blade members can shift monotonically or reversibly between ends. Blade members are stiffened by one or more transverse annular hub members. A method of forming a tangential fan involves forming monolithic structures by casting or by machining from a solid block. Two or more monolithic structures can be joined together, typically by electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Tangential fans produced have mechanical rigidity, accurate tolerances, and low contaminant concentrations. Methods provided by the invention facilitate forming of blade members into an air foil shape. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.

Abstract: A tangential fan and cutoff assembly for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end, and/or a tapered anode assembly. The number of blade members can be constant or variable between ends. The circumferential position of blade members can shift monotonically or reversibly between ends. Blade members are stiffened by optimally selecting the number and placement of hub members to control the natural vibration frequency of the fan. Methods of forming tangential fans include casting, and machining from a solid block. Monolithic structures can be joined, typically by electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Tangential fans produced have mechanical rigidity, accurate tolerances, and low contaminant concentrations. Blade members can be formed into air foil shapes.

Abstract: A tangential fan with cutoff assembly for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end, and/or a tapered anode assembly. The number of blade members can be constant or variable between ends. The circumferential positions of blade members can shift monotonically or reversibly between ends. Blade members can be formed into air foil shapes and are stiffened by one or more transverse annular hub members. Processes for making tangential fans include soldering, casting, and machining from a solid block. Monolithic structures can be joined, typically by soldering or electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Soldering produces substantially silicon-free assemblies. Tangential fans produced in accordance with the invention have improved mechanical rigidity, accurate tolerances, and low contaminant concentrations.

Abstract: An improvement over prior art voltage timing compensation circuits is achieved by incorporating a function generator to provide a more accurate non-linear compensation to pulse timing delay, which is typically a non-linear function of voltage. An improvement over prior art temperature timing compensation circuits is achieved by providing for actual temperature measurements to be made and used to drive the timing compensation circuitry for a more accurate temperature timing compensation than provided by prior art temperature synthesis, while still using a relatively simple compensating circuit. In some embodiments a timing compensation circuit combines both voltage and temperature timing compensation.

Abstract: A low level current travels from a source through the high voltage cable from the remote end to the local end of the cable in a pulse power circuit. The current is detected, and a signal is generated by a bias sensing circuit. If the low level current is not positively detected, no pulse is allowed to occur, preventing accidental damage and high voltage hazard. In some embodiments, the current is coupled to ground at the local end through an isolation inductor, commonly a secondary winding of a high voltage pulse transformer. The low level current then passes through a shunt resistor from ground to an input terminal of the source, thus completing the circuit and generating a voltage between the source input terminal and ground that confirms continuity of the circuit through the high voltage cable.

Abstract: A simple, novel pulse power circuit is described, which improves the net coupling efficiency of a pulse power system used to drive a gas discharge laser, and minimizes current reversal and electrode erosion. The circuit, in accordance with an embodiment of the present invention, incorporates a saturable inductor. Contrary to conventional saturable inductor configurations, in which the saturable inductor is either not saturated or is presaturated in a reverse direction, in the present circuit the saturable inductor is presaturated in the forward direction.The saturable inductor is inserted between the final stage capacitor of a pulse power circuit and a gas discharge load, where it allows forward current but effectively blocks reverse current through the load. Elimination of reverse discharge current reduces electrode erosion and improves discharge chamber life.