Two-stage high frequency pulse tube cooler for refrigeration at 25 K

TL;DR

This paper presents a novel two-stage Stirling-type pulse tube cryocooler designed for efficient refrigeration at 25 K, achieving significant cooling power with optimized geometry and flow impedance matching.

Contribution

It introduces a two-stage pulse tube cryocooler with a unique cold head design and optimized operating conditions for improved low-temperature performance.

Findings

Cooling power of 12.9 W at 25 K

Achieved lowest temperature of 13.7 K

Effective flow-impedance matching

Abstract

A two-stage Stirling-type U-shape pulse tube cryocooler driven by a 10 kW-class linear compressor was designed, built and tested. A special feature of the cold head is the absence of a heat exchanger at the cold end of the first stage, since the intended application requires no cooling power at this intermediate temperature. Simulations where done using Sage-software to find optimum operating conditions and cold head geometry. Flow-impedance matching was required to connect the compressor designed for 60 Hz operation to the 40 Hz cold head. A cooling power of 12.9 W at 25 K with an electrical input power of 4.6 kW has been achieved up to now. The lowest temperature reached is 13.7 K.