SKM 2023 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 21: Poster: Scanning Probe Techniques
O 21.4: Poster
Monday, March 27, 2023, 18:00–20:00, P2/EG
Design of a compact dilution refrigerator integrated in a dry mK UHV STM — •Michael Temmen, Simon Gerber, Michael Meyer, and Wulf Wulfhekel — Physikalisches Institut, Karlsruher Institut für Technologie, Karlsruhe, Deutschland
As energy and helium prices are rising we decided to design a new dry, low temperature Scanning Tunneling Microscope with a compact, low 3He volume dilution refrigerator as the main innovation. Special focus was set on the heat exchanger between the still and the mixing chamber as one of the most crucial parts of the system. Next to the standard solution of a tube-in-tube heat exchanger, a new concept of a heat exchanger consisting of two laser cut metal sheets with deep drawn profiles acting as the channels for the Helium and a plain sheet in the middle as a divider is developed. In order to improve heat transfer while keeping the volume minimal, the surface area is increased by electrodeposition of three dimensional porous silver foam. Comparing this concept with the standard solution, an increase in surface area by a factor of 10 could be achieved with a reduction in 3He volume in the exchanger by a factor of 10. The dilution refrigerator is integrated in a small scale cryostat with a closed helium cycle cooled by a pulse tube with a cooling capacity of 400 mW. The complete dilution refrigerator, cryostat and the STM are home-built.