Superfluid Vortex Cooler

Abstract

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. In this contribution a superfluid vortex cooler ͑SVC͒ is described. A SVC is a cooling device, the operation of which is based on the special properties of superfluid helium ͑He II͒. The SVC is small, simple, has no moving parts, and is gravity independent. It is capable of reaching temperatures as low as 0.65 K. First we have carried out a number of experiments, using a liquid-helium bath as a precooler for the SVC. Various geometries of the cooler components as well as the influence of the working pressure and the base temperature on the performance of the cooler have been investigated. Temperature below 1 K have been reached with a base temperature of 1.4 K. The next step has been combining the SVC with a pulse-tube refrigerator. In a preliminary experiment a lowest temperature of 1.19 K has been reached. Several ways to improve the system are suggested.

Cryocoolers near their low-temperature limit

“…Base temperatures around 1.9 K would allow to precool a vortex cooler by the GM-cooler, similar to Ref. [20], thus possibly extending the temperature range to well below 1.9 K.…”