Sapphire viewing ports

Vacuum news filament evaporation sources during vacuum processing or testing. They can also be used for supplying power to resistance heaters, sublimation or evaporation filaments and for heating interior bake-out mantles. One model (954-5030) has four insulated pins that can supply four separate voltages to devices in a chamber or carry power to two completely isolated circuits. The other model (954-5032) has three insulated pins and a ground rod. Three filaments can be attached easily with integral connectors. Also, the ground rod can support an evaporation source or similar device weighing up to 1 lb. Each feed-through comes on a Conflat flange ready for convenient connection to a vacuum chamber. Electrical ratings are 50 A per pin, 1 kV pin-to-pin, 2 kV pin-to-ground. Varian Associates (Vacuum Division), California, USA Circle number 63 on Reader Enquiry Service card All-stainless-steel diffusion pump A new 20-inch all-stainless-steel diffusion pump of substantially improved performance has been announced by Vacuum Engineering Company, Incorporated. Inert gas-fabricated entirely of 300 series stainless--including the advanced 4-stage high-speed jet assembly-and highly polished, the Model No 1200 is said to have a rated speed of 22,000 litres/sec, with exceptionally high throughput and forepressure tolerance. Optimized boiler and heater design significantly reduce required power input.

Varian vacuum furnace system wetting experiments and research operations requiring vacuum, inert gas, or corrosive atmospheres, there is the VF-500 system. These systems are said to be capable of producing temperatures up to 3,000°C in a contamination-free vacuum environment. Most models offer an ultimate pressure reduction to l x l 0 -1° torr. Featuring hakeable components, the systems are extremely rugged and can withstand long runs to 10,000 hours of continuous operation at constant temperature. Hot-zones up to 16 inches in diameter by 24 inches in length are available. Either a Varian VacSorb pump or a mechanical unit may be used for rough-pumping. Varian offers portable roughing systems which can be moved easily for multi-system operation. Other accessories especially designed for each model are available. Varian Associates (Vacuum Division), California, USA Circle number 62 on Reader Enquiry Service card Compact electrical vacuum feed-throughs Two new compact electrical feed-throughs said to be bakeable to 450°C have been introduced by Varian Associates. These ceramicmetal units for use in high- and ultra-high-vacuum systems come with integral internal connectors and a standard MS connector. They may be used for operating electrical devices or multiple-

Venco diffusion pump Ideally suited for use on large space-simulation, research and vacuum-processing chambers and vacuum furnaces, the pump is also available with matched, ultra-high conductance, stainless and copper combination optically-dense baffle/cryogenic trap and stainless right-angle high-vacuum valve, providing a fully-integrated assembly with net pumping speeds of better than 40 per cent of rated pump speed, ultra-high-vacuum capability of better than 10-1° torr and significantly enhanced system cleanliness. Vacuum Engineering Company Incorporated, Massaclutsetts, USA Circle number 64 on Reader Enquiry Service card

Varian feed-throughs 500

Sapphire viewing ports To the existing range of glass viewing ports for ultra-high-vacuum