Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity - Poster Session
TT 30.61: Poster
Monday, March 31, 2014, 15:00–19:00, P2
Low-Vibration Design of a 4 K Pulse Tube Cooler operated on Helium Compressors of Small Input Power — Jens Falter1,2, Bernd Schmidt1, Andreas Euler1, Marc Dietrich1, André Schirmeisen1,2, and •Günter Thummes1,2 — 1TransMIT-Center for Adaptive Cryotechnology and Sensors, Giessen, Germany — 2Institute of Applied Physics (IAP), Justus-Liebig-University Giessen, Germany
In comparison to conventional Gifford-McMahon coolers, Pulse Tube Coolers (PTC) offer the advantage of having no moving parts at low temperatures. This feature results in high reliability and reduced vibrations of the cold head, which makes the PTC very attractive for highly-sensitive applications. However, due to the periodic compression and expanding cycles in the cold head, also PTCs exhibit two intrinsic effects: (1) a periodic variation in temperature; (2) a periodic elastic deformation ("breathing") of the thin walled pulse- and regenerator-tubes, which leads to residual vibrations. Here we present a two-stage 4 K PTC cold head which was especially designed to work with compressors of low input power in order to minimize these intrinsic effects. Nevertheless, small variations in temperature and residual vibrations remain due to their intrinsic nature. Further reduction of the temperature oscillations can be achieved with metal plates of low thermal diffusivity and the residual vibrations can be further reduced by successfully decoupling the cooler from the experiment.