A paper describes a 1-K-pot that works with a commercial pulse tube cooler for astrophysics instrumentation testbeds that require temperatures <1.7 K. Pumped liquid helium-4 cryostats were commonly used to achieve this temperature. However, liquid helium-4 cryostats are being replaced with cryostats using pulse tube coolers.

The closed-cycle 1K-pot system for the pulse tube cooler requires a heat exchanger on the pulse tube, a flow restriction, pump-out line, and pump system that recirculates helium-4. The heat exchanger precools and liquefies helium-4 gas at the 2.5 to 3.5 K pulse tube cold head.

This closed-cycle 1-K-pot system was designed to work with commercially available laboratory pulse tube coolers. It was built using common laboratory equipment such as stainless steel tubing and a mechanical pump. The system is self-contained and requires only common wall power to operate. The lift of 15 mW at 1.1 K and base temperature of 0.97 K are provided continuously. The system can be scaled to higher heat lifts of ≈30 to 50 mW if desired.

Ground-based telescopes could use this innovation to improve the efficiency of existing cryogenic systems or as a basis of new systems.

This work was done by Christopher G. Paine, Bret J. Naylor, and Thomas Prouve of Caltech for NASA’s Jet Propulsion Laboratory. NPO-48355

This Brief includes a Technical Support Package (TSP).
Recirculating 1-K-Pot for Pulse-Tube Cryostats

(reference NPO-48355) is currently available for download from the TSP library.

Don't have an account? Sign up here.

NASA Tech Briefs Magazine

This article first appeared in the July, 2013 issue of NASA Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.