This award supports Mark W. Meisel and others of the Microkelvin Research Laboratory of the University of Florida for an international research collaboration in physics and cryogenic engineering with Giorgio Frossati, Director, and others, of the High Magnetic Field/Low Temperature Laboratory of the University of Leiden, The Netherlands. Their physics collaboration involves the study of highly polarized normal liquid and superfluid Helium-3 and the magnetic phase diagram of solid Helium-3. Meisel offers substantial ultrasonic expertise to the study of polarized liquid Helium at Leiden. Both groups will benefit from an exchange of experience as each team studies solid helium-3 under slightly different conditions. Their cooperative work in cryogenic engineering will benefit greatly from the pioneering work at Leiden. They will work jointly on the design and construction of a high cooling power dilution refrigerator (DR) that will encircle a nuclear demagnetization refrigerator (NDR.) Nesting the DR/NDR system will shorten the length of the high magnetic field/low temperature cryostats. This will reduce the intrinsic vibration problems associated with five- meter-long cryostats and it will eliminate the need for long, narrow neck dewars that are difficult to fabricate. The first prototype will be built in Leiden and the second generation system will be constructed for the University of Florida. It will be ideally suited for a low temperature station at the new NSF High Magnetic Field Facility presently being planned.
