Electronic cryogenic equipment

Vacuum news Fast, automatic depa&ion of thin films Varian Associates, Vacuum Division, USA have introduced two new deposition systems designed for the continuous automatic processing of semiconductor components. In-line systems, with separate entry and exit air-locks, and rapid-cycling systems, with single entry/exit air-locks, are available. Both are straight line configurations of modular construction providing flexibility in selection of the number of processing chambers. The deposition chamber may accommodate a Varian rf sputtering module and e-Gun Evaporation Source-or a filament deposition unit. Diffusion or ion oumoing mav be employed. The rapid cy&n _evapor&or deposits aluminium at 3000 1 /min with a 6 kW e-Gun Source, clean, ultrahigh vacuum is obtained by a 500 litre/sec VacIon pump, a titanium sublimation cartridge and a liquid nitrogen cryopanel. Roughing of the entry/exit air-lock is bv a GASP aspirator and t&e VacSorb pumps. In the continuous In-line Deoosition unit. cycling is completely automatic, carrying the substrate trays from the entry lock to the deposition chamber. Nichrome may be deposited by an rf Plasma Peak sputtering module or gold by two 6 kW e-Gun sources. A constant vacuum is maintained by a 6inch, VE-60 diffusion pump system while the air-locks are pumped by a 2-inch system. Varlan Associates, Vacuum Division, USA Circle number 49 on Reader Enquiry Service card Vacuum shrouds Bemco Inc, of California, USA, announce the availability of their Bemcoil vacuum shrouds, primarily for space simulation chambers. These shrouds are supplied according to customer specifications of chamber size and temperature and gradient requirements. The Bemcoil element consists of -a contoured plate of stainless steel, double embossed with welded self-venting channels which permit rapid and tota flooding of the conditioning agent throughout the entire chamber area. All shrouds are lightweight, rugged and mass spectrometer leak-tested-with high emissivity interiors and low emissivitv exteriors. The units afford fast response and are readily adaptable to refrigeration by liquid nitrogen, brine or gas with an overall temperature range of -300°F to 500°F. A new 56 page General Catalogue describes the shrouds as well as the company’s range of environmental test equipment and space simulation facilities. Bemco Inc, USA Circle number 50 on Reader Enquiry Service card Electronic ayogenic equipment Cryotronics Inc, USA, offer a range of thermometers, level controllers and temperature controllers for operation at cryogenic temperatures. Model ML IOOA cryogenic thermometer uses solid state paramagnetic materials as thermometric indicators and is designed to provide

Varian rapid-cycling air-locked vacuum evaporator

Bemco’s vacuum shrouds reliable and accurate measurement of temperatures in the range 0.3”K to 25°K. The low temperature probe operation is based on the temperature dependence of the magnetic susceptibility of selected solid state materials, including ruby crystals. The mutual inductance of the probe is observed by an ac electronic bridge with a modular plug-in signal generator tuned to 17 or 155 cycles and a modular, high sensitivity, low noise amplifier having both narrow band and noise filters. Two probes are supplied, one for the range 0.3-5”K, the other for 1.5-25°K. In operation, the instrument is tuned to a null, which may be observed on an oscilloscope connected to the output terminal. The readings of the inductive balance at the null, which are conveniently read from the dials, give the absolute probe temperature, with reference to appropriate calibration data. Other products include: the Cryolevel (ML 2OOC)which will maintain a predetermined level of liquid in a cryogenic container, to within an adjustable range of f Ib inch to 3 ft; liquid helium bath temperature regulator (model 13OOA), providing automatic continuous control of f10 x 10-O degrees Kelvin in the range between 1°K and 4°K. The Cryodial (ML 1400-A) pro-

portional temperature controller providing f0.020”K in the range 4.2 to 300°K.; and the Cryominder (MC-2301), a mimature proportional temperature controller for the temperature range 25-273°K with control to fl”K. Cryotronlcs Inc, USA Circle number 51 on Reader Enquiry Service card Ultrahigh temperature furnace Astro Industries of Santa Barbara, California, have introduced a versatile laboratory furnace, Model 257OC, designed to provide temperatures to 3ooo”C in inert gas or vacuum, with a heat-up time of less than 15 minutes. Readily replaceable graphite elements operate in vertical or horizontal configuration and provide safe operation at elevated pressures. The furnace is equipped with dual radial ports and an axial port with access to the working zones from both ends. Sustained operation at 5500°F is obtained in a hot zone 2.5 inches in diameter by 7 inches long. Automatic temperature control, accurate to 0.1 per cent, may be provided as well as mufae tubes, dilatometers, calorimeters, black body cavities and other accessories. These furnaces are constructed to be capable of 347