Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Cryogenic Detectors and Cryotechnique
TT 17.8: Vortrag
Mittwoch, 7. September 2022, 11:30–11:45, H22
Cooling performance of a 4 K two-stage pulse tube cryocooler in tilted operation along main azimuthal orientations — •Jack-Andre Schmidt1,2, Bernd Schmidt1,2, Jens Falter1,2, and Andre Schirmeisen1,2 — 1Justus-Liebig-University Giessen — 2TransMIT GmbH
Closed-cycle cryocoolers, here Gifford-McMahon (GM) type pulse tube cryocoolers (PTC), offer long measurement periods and low maintenance, but they exhibit undesired intrinsic effects due to the working principle [1]. Cooling performance of GM-type PTCs is strongly depending on the orientation and is set to be strictly vertical, which is not suitable for experiments where the cryostat needs to be tilted [2, 3]. We report an experimental study of the effect of tilting from vertical orientation on the cooling performance of a U-shaped 4 K pulse tube cryocooler (PTC) with 7 kW electrical input power. An investigation of cooling performance over tilt angles from 0 to 60 degree for selected azimuthal orientations of the PTC is performed. The non-coaxial arrangement of the tubes suggests an asymmetric cooling performance while tilting along the first or second stage heat exchanger due to natural convection in the pulse tubes [3]. The increase of no-load temperatures upon tilting by +/- 50 degree will be discussed. While the regime of tilt angles within 30 show moderate loss in cooling power an almost sudden decrease of cooling power is revealed and analyzed for high tilt angles.
[1] G. Thummes et al., Cryocoolers 9 (1997) 393
[2] T. Tsan et al., Cryogenics 117 (2021) 103323
[3] C. Risacher et al., IEEE 39 (2014)
[4] L. Zhang, et al., Cryogenics 51 (2011) 85