Münster 1997 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 6: Postersitzung I: Mesoskopie(1-21), amorphe Metalle und Defektsysteme(22-29), Kryotechnik, Kernmagnetismus(30-37), festes N₂(38), Quantenflüssigkeiten und -kristalle(39-48), dünne supraleitende Filme(49-68), schwere Fermionen und Kondosysteme(69-92), Fullerene(93-94)

TT 6.32: Poster

Dienstag, 18. März 1997, 09:30–13:00, Z1

A small sized Cold-Valve for Operation in Superfluid Helium — •K. Taubenreuther¹, V. Chagovets², P. Schmidt¹, M. Huebner¹, J. Leib¹, and G. Eska¹ — ¹Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth — ²Verkin Institute, Ukrainian Academy of Sciences, Karkov 310164, Ukraine

Cold valves are a necessity for many experiments with normal and superfluid Helium. In the most common designs Helium itself is used as the hydraulic fluid which operates the valve by moving a needle. The positioning of this needle is sometimes not very reproducible because flexible metallic balgs are used in the design. We describe several designs of small size which are using membranes instead of balgs to operate the needle with a pressure difference of about 1 bar. Depending on the needle- and membrane-material such devices can be built superleak tight with a leak-rate less 10⁻¹⁰mbar l/sec. Even many cool-down- and open/close-cycles have not deteriorated this value. Difficulties and performances of different types of such valves are discussed.