The cryogenic system for the SCH and the 45 T hybrid at the NHMFL

Abstract

A new cryogenic system is under construction at the National High Magnetic Field Laboratory (NHMFL) for the cooling of the Series-Connected Hybrid (SCH) magnet as well as the existing 45 T hybrid system. The SCH is a vertical bore, 36 T magnet under development at the NHMFL and it will be installed at the NHMFL in 2013. The 45 T hybrid magnet system producing a 45 T steady field has been operating successfully as a user facility since 1999. The existing cryogenic system at the NHMFL has been in service since 1994 and it is used for supplying Liquid Helium (LHe) to the users and also cooling the 45 T hybrid magnet. The new system has a specified refrigeration capacity of 750 W at 4.5 K and will replace the current refrigerators after its construction due to the increasing maintenance in current refrigerators and the increasing LHe demand by the users at the NHMFL. The design of the new cryogenic system, consisting of a main refrigerator, a distribution system and a gas management and purification system, and its status are presented in this paper.