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Cryosorb cold traps
Vacuum news aluminium borosilicatc. The glass is formed by drawing into sheets and then cut into finished pieces. A typical smoothness is less than micro-inch. A publication giving comprehensive details on chemical constituents and properties is available from Electrosil Limited. Electrosil Limited, UK Circle number 62 on Reader Enquiry Service card New Instrumentation from Sloan Sloan Instruments Corporation have announced that their deposit thickness monitor, Model DTM-2A, has been superseded by Model DTM-3. The two models are exactly the same except that the D T M 3 has an extra 100-kc range which has been added for convenience for " t h i c k " film deposition. The D T M now has ranges of 1, 3, 10, 30 and 100 kc at no additional cost. The addition of the 3-kc range is said to make the D T M more convenient for use in optical applications where the deposition of ¼ wavelengths of magnesium fluoride and cadmium sulphide require a frequency setting of 1.5 kc. Previously optical users had to use the 10-kc range or use a 50 per cent shield to get them on the l-kc scale. The addition of the 100-kc range extends the range of the instrument for single depositions 3.3 times over the previous 30 kc, thus providing greater applicability for long a n d / o r thick deposition. The Corporation have also announced the O M N I - I , a complete system used for the automatic control of thickness and rate of thinfilm vacuum deposition. Two O M N I - I ' s can be slaved together to yield an infinite variety of alloy or compound compositions from multiple evaporation sources. Heretofore, thin-film workers used a deposit thickness monitor (DTM) and deposit rate control (DRC) to achieve full system contlol. The OMNI-1 is a single unit with all of the features of the D T M and D R C plus the following advantages: (1) A dual high-low set point meter has been added to the thickness monitoring section. The low set point appropriately opens the substrate shutter once the source is under rate control and the high set point closes the shutter once the appropriate thickness has been reached. (2) Automatic re-zeroing has been added. When desired, the instrument now re-zeros itself automatically after every deposition. Sloau l~strumems Corporation, California, USA Circle number 63 on Reader Enquiry Service card Hot gas micro-bonder The hot gas micro-bonder type B400, recently introduced by G V Planer Limited, utilizes a fine high-temperature gas jet to effect bonding, in particular, hot-gas soldering of micro-joints, and the like. I m p o r t a n t uses of the equipment are said to include the facebonding of semiconductor chips to metallic thin-film areas in micro-circuits, attachment of leads in electronic-component manufacture and solder bonding of wires to film-circuit patterns or semiconductor devices.
B400 hot gas micro-bonder in use
The gas stream, e,g. nitrogen or a nitrogen - hydrogen mixture, is heated electrically at a thermostatically controlled temperature of up to 400 °C and the applications of the jet can be controlled at preset durations of up to 15 seconds. The flow-rate of the gas is controlled by means of a pressure regulator and gauge. Jet diameters ranging from 0.01 to 0.10 inch can be obtained by using interchangeable nozzles. Provision is made in the case of the larger diameter nozzles for use of a centrally located projecting pin to retain the component to be joined during the bonding operation, where required. A thermostatically controlled, heated sub-stage with micromanipulator position control is used to support the components to be bonded. A vacuum facility in the sub-stage serves to retain the component during operation, and a vacuum tweezer is provided for the handling of small pieces. A binocular microscope is included in the equipment together with means of variable intensity illumination. G VPlaner Limited, UK Circle number 64 on Reader Enquiry Service card Line trap with built-in valve The Vacuum Division of Varian Associates has introduced a roughing line trap with a built-in valve. This new unit is claimed to speed up rough pumping operations by capturing water vapour and to improve the cleanhness of a vacuum system by trapping backstreaming oil. A vacuum system can also be evacuated to the 10 -s torr region and held at that pressure by just a two-stage mechanical
Varian trap valves:left, cryotrap valve; right, molecular-sieve trap valve pump and this trap valve. Installation is simplified with two standard 2t-inch outer diameter ConFlat flanges that mate with matching flanges. Varian is offering two types of trap valves. The molecular-sieve trap valve uses 500 g of zeolite material for trapping action. The cryotrap valve uses 1 litre of liquid-mtrogen to provide almost unlirmted trapping capacity. Models of both types are available with integral heaters for either 110 or 220 V operation. Varian Associates, Vacuum Division, California, USA Circle number 65 on Reader Enquiry Service card Cryosorb cold traps Vacuum physicists and cryogenic engineers at Granville-Phillips have carefully designed a cryogenically cooled adsorption or condensation cold trap that permits the use of diffusion pumps even in the most critical operations. These traps are said to effectively prevent oil and oil vapours from creeping or diffusing hack into a properly operated system for extended periods of time. The manufacturers recommend Cryosorb traps for use as an economical method for trapping high-vacuum systems. When supplied with metal-to-metal flanges the traps are bakeable to 450 °C and are useful in ultra-high-vacuum and ultra-clean systems. Due to their all-stainless-steel construction, Cryosorh cold traps are said to be especially useful on mercury pumped systems. 91
Vacuum news 411.
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electrical cable to a small control unit mountable on a hospital-type trolley, The temperature of the tip is fully variable fro m -- 140 ° to + 20 °C by means of a miniature heater in the probe which is b o t h controlled and indicated on the front panel of the control unit. A second heater in the probe is provided for rapid de-frosting, normally operated from a foot pedal. De-frosting from --60 ° to 0°C can be achieved in less than 6 sec. In action, the probe is both cooled down internally and filled with liquid nitrogen at --196°C while placed upside-down m a sealed holder on top of the control unit; automatic pressure filling can then take place from a vacuum-insulated glass container inside the control box by means of a valve on the front panel. This container holds sufficient liquid nitrogen for a day's operation. The entire probe can be sterilized m an autoclave at 125 °C and when not in use is stored in its filling position on top of the control unit inside a removable glass dome. Spembly Technical Products Limited, UK Circle number 67 on Reader Enquiry Service card
Air-operated refrigerator to replace liqnid-nitrogen in cold traps The Welch Scientific Company have recently introduced a completely mechanical device t h a t uses air as both a refrigerant a n d power source to refrigerate cold traps to - 140°C. The Welch product, called the Series 3150 cryogenic refrigerator, uses ordinary compressed air. It contains a reciprocating engine that cycles a small charge of air, permits it to expand and cool, traps the cold and allows warmer air to escape. The cycle requires less t h a n a second. In 45 minutes, the refrigerator reaches a temperature of -- 140 °C. Sectional view of eryosorb cold trap Cryosorb traps are completely serf-contained, integral units. They are constructed entirely of Series 300 stainless steel, carefully processed, finished and assembled to meet the rigid requirements of ultra-high vacuum. These traps are optically tight and all joints are made by completely programmed and automated inert gas-welding techniques, and are guaranteed to be free of all leaks greater than 10 -x° standard eroS/see. The integral, vacuum-insulated coolant reservoir in each size Cryosorb trap has sufficient liqmd-nitrogen storage capacity to permit overnight operation without refilling. The double-wall construction of the interior walls prevents the vacuum from "seeing" the effects of the changing coolant level and remains impervious even to the burst of warm a~r that usually accompanies the filling operation of a trap. A flexible, stainless steel bellows is inert-gas welded at the filler openings between the outer housing and the coolant reservoir. A shielded fill and vent tube assembly is provided to prevent condensation from falling into the trap. A simple extension accessory enables the trap to be filled conveniently even when the trap is mounted in a pumping system cabinet. Automatic level-control sensors can easily be installed if required. Standard ASA and other stainless steel flanges designed to mate with diffusion pumps manufactured by most major vacuum-equipment manufacturers are available. On standard Cryosorb cold traps the pump flange has a smooth, flat face and the system flange is grooved for a Viton O-ring. Indium wire or other soft wire can be used to make a non-breakable, all-metal seal with this type of flanging. Custom-assembled Cryosorb traps are available with various types of ultra-high-vacuum, bakeable, metal-to-metal seal flanges. Granville-Phillil~s ComlTany, Colorado, USA Circle number 65 on Reader Enquiry Service card
Cryosurgical unit A cryosurgical unit, claimed to be the first British low-temperature instrument for eye surgery use will be exhibited at the first BioMedical Engineering Exhibition, 28 to 31 M a r c h 1966 at the HorUcultural Society's New Hall, Westminster, L o n d o n SW1. It has been designed by Spembly Techmcal Products Limited to specifications by Mr K Rubinstein of the Birmingham and Midland Eye Hospital. The instrument consists of a vacuum-insulated liquid-nitrogencooled probe, with interchangeable tips, connected by a single
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Three models of cryogenic refrigerator shown with cold surface extensions attached. From left to right: 3150, 3150A, 3150B In comparing the new refrigerator to liquid-nitrogen, Welch point to the following advatages: 1. User convenience; no need to prepare trap or maintain liquidnitrogen level. 2. Cash savings; tests conducted by Welch in operating popular makes of leak detectors show substantial annual savings.
B400 hot gas micro-bonder in use
The gas stream, e,g. nitrogen or a nitrogen - hydrogen mixture, is heated electrically at a thermostatically controlled temperature of up to 400 °C and the applications of the jet can be controlled at preset durations of up to 15 seconds. The flow-rate of the gas is controlled by means of a pressure regulator and gauge. Jet diameters ranging from 0.01 to 0.10 inch can be obtained by using interchangeable nozzles. Provision is made in the case of the larger diameter nozzles for use of a centrally located projecting pin to retain the component to be joined during the bonding operation, where required. A thermostatically controlled, heated sub-stage with micromanipulator position control is used to support the components to be bonded. A vacuum facility in the sub-stage serves to retain the component during operation, and a vacuum tweezer is provided for the handling of small pieces. A binocular microscope is included in the equipment together with means of variable intensity illumination. G VPlaner Limited, UK Circle number 64 on Reader Enquiry Service card Line trap with built-in valve The Vacuum Division of Varian Associates has introduced a roughing line trap with a built-in valve. This new unit is claimed to speed up rough pumping operations by capturing water vapour and to improve the cleanhness of a vacuum system by trapping backstreaming oil. A vacuum system can also be evacuated to the 10 -s torr region and held at that pressure by just a two-stage mechanical
Varian trap valves:left, cryotrap valve; right, molecular-sieve trap valve pump and this trap valve. Installation is simplified with two standard 2t-inch outer diameter ConFlat flanges that mate with matching flanges. Varian is offering two types of trap valves. The molecular-sieve trap valve uses 500 g of zeolite material for trapping action. The cryotrap valve uses 1 litre of liquid-mtrogen to provide almost unlirmted trapping capacity. Models of both types are available with integral heaters for either 110 or 220 V operation. Varian Associates, Vacuum Division, California, USA Circle number 65 on Reader Enquiry Service card Cryosorb cold traps Vacuum physicists and cryogenic engineers at Granville-Phillips have carefully designed a cryogenically cooled adsorption or condensation cold trap that permits the use of diffusion pumps even in the most critical operations. These traps are said to effectively prevent oil and oil vapours from creeping or diffusing hack into a properly operated system for extended periods of time. The manufacturers recommend Cryosorb traps for use as an economical method for trapping high-vacuum systems. When supplied with metal-to-metal flanges the traps are bakeable to 450 °C and are useful in ultra-high-vacuum and ultra-clean systems. Due to their all-stainless-steel construction, Cryosorh cold traps are said to be especially useful on mercury pumped systems. 91
Vacuum news 411.
~*
electrical cable to a small control unit mountable on a hospital-type trolley, The temperature of the tip is fully variable fro m -- 140 ° to + 20 °C by means of a miniature heater in the probe which is b o t h controlled and indicated on the front panel of the control unit. A second heater in the probe is provided for rapid de-frosting, normally operated from a foot pedal. De-frosting from --60 ° to 0°C can be achieved in less than 6 sec. In action, the probe is both cooled down internally and filled with liquid nitrogen at --196°C while placed upside-down m a sealed holder on top of the control unit; automatic pressure filling can then take place from a vacuum-insulated glass container inside the control box by means of a valve on the front panel. This container holds sufficient liquid nitrogen for a day's operation. The entire probe can be sterilized m an autoclave at 125 °C and when not in use is stored in its filling position on top of the control unit inside a removable glass dome. Spembly Technical Products Limited, UK Circle number 67 on Reader Enquiry Service card
Air-operated refrigerator to replace liqnid-nitrogen in cold traps The Welch Scientific Company have recently introduced a completely mechanical device t h a t uses air as both a refrigerant a n d power source to refrigerate cold traps to - 140°C. The Welch product, called the Series 3150 cryogenic refrigerator, uses ordinary compressed air. It contains a reciprocating engine that cycles a small charge of air, permits it to expand and cool, traps the cold and allows warmer air to escape. The cycle requires less t h a n a second. In 45 minutes, the refrigerator reaches a temperature of -- 140 °C. Sectional view of eryosorb cold trap Cryosorb traps are completely serf-contained, integral units. They are constructed entirely of Series 300 stainless steel, carefully processed, finished and assembled to meet the rigid requirements of ultra-high vacuum. These traps are optically tight and all joints are made by completely programmed and automated inert gas-welding techniques, and are guaranteed to be free of all leaks greater than 10 -x° standard eroS/see. The integral, vacuum-insulated coolant reservoir in each size Cryosorb trap has sufficient liqmd-nitrogen storage capacity to permit overnight operation without refilling. The double-wall construction of the interior walls prevents the vacuum from "seeing" the effects of the changing coolant level and remains impervious even to the burst of warm a~r that usually accompanies the filling operation of a trap. A flexible, stainless steel bellows is inert-gas welded at the filler openings between the outer housing and the coolant reservoir. A shielded fill and vent tube assembly is provided to prevent condensation from falling into the trap. A simple extension accessory enables the trap to be filled conveniently even when the trap is mounted in a pumping system cabinet. Automatic level-control sensors can easily be installed if required. Standard ASA and other stainless steel flanges designed to mate with diffusion pumps manufactured by most major vacuum-equipment manufacturers are available. On standard Cryosorb cold traps the pump flange has a smooth, flat face and the system flange is grooved for a Viton O-ring. Indium wire or other soft wire can be used to make a non-breakable, all-metal seal with this type of flanging. Custom-assembled Cryosorb traps are available with various types of ultra-high-vacuum, bakeable, metal-to-metal seal flanges. Granville-Phillil~s ComlTany, Colorado, USA Circle number 65 on Reader Enquiry Service card
Cryosurgical unit A cryosurgical unit, claimed to be the first British low-temperature instrument for eye surgery use will be exhibited at the first BioMedical Engineering Exhibition, 28 to 31 M a r c h 1966 at the HorUcultural Society's New Hall, Westminster, L o n d o n SW1. It has been designed by Spembly Techmcal Products Limited to specifications by Mr K Rubinstein of the Birmingham and Midland Eye Hospital. The instrument consists of a vacuum-insulated liquid-nitrogencooled probe, with interchangeable tips, connected by a single
92
Three models of cryogenic refrigerator shown with cold surface extensions attached. From left to right: 3150, 3150A, 3150B In comparing the new refrigerator to liquid-nitrogen, Welch point to the following advatages: 1. User convenience; no need to prepare trap or maintain liquidnitrogen level. 2. Cash savings; tests conducted by Welch in operating popular makes of leak detectors show substantial annual savings.