Title: "Helium Thermosiphon Cooling of Superconducting Magnets"

Abstract

The increased cost of helium has become an important consideration in the design of superconducting magnet systems that are maintained at operating conditions for long periods of time. A good example of such systems are whole body MRI magnets, which traditionally require thousands of liters of liquid helium for cooldown and operation. The high cost of liquid helium has stimulated efforts to design and build superconducting magnet systems that require a much smaller helium inventory. One way to accomplish this goal is to utilize a cooling system consisting of a liquid helium thermosiphon and closed cycle helium cryocooler. In the case of MRI magnets, these cooling systems can have a self-contained helium inventory of less than the equivalent of 10 liquid liters.

The talk will present the basic operating principles of helium thermosiphons and their application to superconducting magnet cooling. In addition to steady state cooling performance, transient issues such as cooldown, magnet charging and recovery from quench will be discussed.

Professor Steven van Schiver

Dr. Van Sciver is an Emeritus Professor with Florida State University currently working as a consultant to industry in cryogenic science and technology. Prior to retirement he was a Distinguished Research Professor and John H. Gorrie Professor of Mechanical Engineering and Program Director at the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, FL. Dr. Van Sciver joined the FAMU-FSU College of Engineering and the NHMFL in 1991, initiating and teaching in a graduate program in magnet and materials engineering and in cryogenic thermal sciences and heat transfer. He also led the NHMFL development efforts of the cryogenic systems for the NHMFL Hybrid and 900 MHz NMR superconducting magnets. Between 1997 and 2003, he served as Director of Magnet Science and Technology at the NHMFL. Dr. Van Sciver is a Fellow of the ASME and the Cryogenic Society of America and former American Editor for the international journal Cryogenics. He is the 2010 recipient of the Kurt Mendelssohn Award and the 2017 recipient of the Samuel Collins Award.