Sub-Kelvin refrigeration with dry-coolers on a rotating system

TL;DR

This paper presents a novel cryogenic system capable of achieving sub-Kelvin temperatures on a rotating platform, enabling scientific experiments that require ultra-cold conditions during rotation.

Contribution

The authors developed and tested a rotating cryogenic system with rotary joints, achieving stable sub-Kelvin temperatures suitable for scientific applications on rotating platforms.

Findings

Achieved 0.23 K temperature with over 24 hours hold time.

System operated successfully during continuous rotation at 20 rpm.

Minor temperature differences observed between rotating and non-rotating states.

Abstract

We developed a cryogenic system on a rotating table that achieves sub-Kelvin conditions. The cryogenic system consists of a helium sorption cooler and a pulse tube cooler in a cryostat mounted on a rotating table. Two rotary-joint connectors for electricity and helium gas circulation enable the coolers to be operated and maintained with ease. We performed cool-down tests under a condition of continuous rotation at 20 rpm. We obtained a temperature of 0.23 K with a holding time of more than 24 hours, thus complying with catalog specifications. We monitored the system's performance for four weeks; two weeks with and without rotation. A few-percent difference in conditions was observed between these two states. Most applications can tolerate such a slight difference. The technology developed is useful for various scientific applications requiring sub-Kelvin conditions on rotating platforms.