High-power closed-cycle $^4$He cryostat with top-loading sample exchange

TL;DR

This paper presents a versatile, cryogen-free $^4$He cryostat with efficient top-loading and recondensation capabilities, achieving 1 K base temperature and high cooling power suitable for laboratory use.

Contribution

The development of a flexible, cryogen-free cryostat with rapid sample exchange and continuous helium recondensation, enhancing laboratory cryogenic experiments.

Findings

Achieves 1.0 K base temperature within 7 hours.

Provides 250 mW cooling power at 1.24 K.

Enables fast sample exchange within 75 minutes.

Abstract

We report on the development of a versatile cryogen-free laboratory cryostat based upon a commercial pulse tube cryocooler. It provides enough cooling power for continuous recondensation of circulating $^4$He gas at a condensation pressure of approximately 250~mbar. Moreover, the cryostat allows for exchange of different cryostat-inserts as well as fast and easy "wet" top-loading of samples directly into the 1 K pot with a turn-over time of less than 75~min. Starting from room temperature and using a $^4$He cryostat-insert, a base temperature of 1.0~K is reached within approximately seven hours and a cooling power of 250~mW is established at 1.24~K.