A Long Lifetime Balloon-Borne Cryostat and Magnetic Refrigerator

A long lifetime, low cost, vapor-shielded liquid neon and liquid helium cryostat and an adiabatic demagnetization refrigerator have been developed for cooling a bolometric radiometer to 0.1 K for mm and sub-mm observations of the cosmic microwave background. This is the first phase of a development effort for a very long hold time system for use in NASA’s 100 Day Ultra Long Duration Balloon Project. This type of system has additional applications in sub-orbital and ground-based research in millimeter, sub-millimeter, infrared, and x-ray astrophysics. A detailed description of the design, analysis, and performance of the system is presented and plans for follow-up design improvements are discussed.