Miniature Cryocooler for Hand-Held Gamma Ray Spectrometer.

Creare is a leading innovator in cryocooling technology, and we have had the opportunity to work on several interesting and challenging cryocooler projects in the aerospace and defense fields. We have also provided consulting services to other engineering firms, performing testing and feasibility studies of their cryogenic technology.

As part of NASA’s Mars mission, we developed a split, mixed-gas, Joule-Thomson (J-T) cryocooler to liquefy fuel on Mars for the return flight to Earth. In-Situ Resource Utilization (ISRU) is a critical technology for future planetary and lunar exploration. It allows the carbon dioxide in the Mars atmosphere to be combined with hydrogen brought to the planet to form methane and oxygen for use as rocket propellants. Creare’s project was to develop a cryocooler to cool the gases to liquid form, requiring a temperature drop from 240K to 90K. Our innovative cryocooler has been demonstrated to be very lightweight and highly efficient.

At the Kennedy Space Center, launch pad crews and rescue personnel use Self-Contained Atmosphere Protective Ensemble (SCAPE) suits with cryogenic air packs on a daily basis to protect themselves from the hazards of hypergolic rocket propellants. Any heat leak into a cryogenic air tank causes the stored air to expand and vent, creating the need for frequent recharging. To circumvent this problem, Creare engineers are designing and building cryogenic cooling systems for a cryogenic air self-contained breathing apparatus (SCBA) with zero venting and quick disconnect capabilities. We have designed lightweight, low-cost heat exchangers and adjustable J-T throttles to provide cooling for the SCBA.

Zero-venting, quick-disconnect super critical air tanks also can assist Homeland Security personnel, fire fighters, search-and-rescue personnel, and Level A Hazmat teams. Zero-venting technology fills critical needs in space exploration as well. Recognizing this potential, a Creare feasibility study for NASA is currently underway to examine the use of a closed-loop, mixed-gas J-T cryocooler for zero-boiloff cryogenic storage on the lunar surface.

Gamma ray spectrometers are a vital tool for detecting nuclear materials to counter the threat of radiological and nuclear terrorism. The High Purity Germanium (HPGe) crystals in the detectors must operate at cryogenic temperatures to achieve high energy resolution. For the Department of Homeland Security, we are developing a miniature, mixed-gas J-T refrigeration cycle for high efficiency cooling and an innovative, oil-free compressor for low vibration. Our lightweight total cooling system, is designed to operate in a hand-held device for eight hours.

As these examples illustrate, engineering requirements in miniaturization, reduced power consumption, and flight-qualification continually challenge us to advance our cryogenic technology.

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