A paper describes a 1-K-pot that works with a commercial pulse tube cooler for astrophysics instrumentation testbeds that require temperatures
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.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL) detailing the development of a Recirculating 1-K-Pot for Pulse-Tube Cryostats, identified by the NASA Tech Briefs number NPO-48355. This innovative system is designed to operate at very low temperatures, specifically around 1 Kelvin, and is notable for being a closed-cycle system that recycles helium-4 gas, distinguishing it from other systems that do not recycle and thus require expendable resources.
The cooling process begins with a regenerator tube that cools gas from approximately 50K to 4K before it enters a second stage heat exchanger. Here, the gas condenses into liquid helium, which is then drawn into a collection pot. The system includes a pump line that connects to a commercial oil-free roughing pump, facilitating the circulation of helium gas. The design allows for a heat lift of 15 mW at 1.1K, with a base temperature of 0.97K, making it suitable for various cryogenic applications.
The document emphasizes the novelty of this system, highlighting that it is the only known closed-cycle 1K-pot based on a pulse-tube cryocooler. The research was conducted between June and December 2010, and while a similar system was reported in literature shortly thereafter, it does not incorporate the recycling feature, which is a significant advantage of the JPL design.
The potential applications of this technology are particularly relevant to NASA's aeronautical and space activities, as it can be effectively utilized in pulse-tube-based cryogenic test beds where a 1K stage is necessary. The flexibility of the pump line design allows for a wide range of heat lifts at 1K, making it a versatile solution for future cryogenic systems.
The document also includes contact information for further inquiries related to research and technology in this area, emphasizing the collaborative nature of NASA's Innovative Partnerships Program. Overall, this Technical Support Package showcases advancements in cryogenic technology that could have significant implications for future aerospace applications.
