Insulator and Heat Exchanger for Ultra High Vacuum, High Voltage Discharge Chamber
									By W. J. Wheeler Glass Technician University of Wisconsin Madison, Wisconsin whee112923@aol
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				Introduction This paper contains information and construction details for a ten-foot long, eighteen inch diameter glass tube, and heat exchanger of twenty one, 1" I.D. by 10 ½ foot long tubes, joined at both ends to loops 16 1/2 inch O.D. of the same size tubing. Equipment used and sealing techniques are described and photographs and drawings are included. The construction of a high vacuum discharge chamber required glass assemblies with the following characteristics.
		1.Made of Pyrex glass, heavy walled and strain free. 2.One tube, eighteen inches in diameter, ten foot in length, both ends open. 3.One assembly of twenty-one parallel tubes, 1" I.D., 10 1/2 feet long, joined to a glass ring of the same size tubing at both ends, with an entrance and exit tube incorporated into their design. To be vacuum tight. (Vacuum outside and 14.7 psi inside). 4.All assemblies to withstand temperature ranges from room temperature, bake out at 450 C., and operate at liquid nitrogen temperature at a pressure of 10-11 Torr. 5.All assemblies to be installed in a 24" diameter by 14 foot long stainless steel chamber with removable end bells.
					Fabrication of 18" Diameter Glass Tube A supplier of 18" tubing was located *, however, four foot lengths were maximum lengths available. Not having a lathe of 18" capacity, it was decided to build a machine to join two four-foot lengths to one two-foot length. The design of the machine is as follows. The 18" tube was supported internally with a specially designed chucking assembly on a central 6 inch, 14 foot long steel pipe, set on two "A" frames, with roller bearings at each end, and rotated by our Litton HSA lathe through a belt drive. [Figure 1] *Corning Glass Works, Corning, New York
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