High field NMR apparatus with excess cooling power and integrated helium re-liquification

US8633692B2 · kind B2 · utility

Assignee

• Bruker Biospin GmbH · DE

Inventors

• Marco Strobel · Karlsruhe, DE
• Holger Liebel · Büderich, DE

Key dates

• Filing date: Jul 27, 2011
• Grant date: Jan 21, 2014
• Expiry date: Jul 15, 2032

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F25B9/145
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A nuclear magnetic resonance (NMR) apparatus (10) comprises a superconducting main field magnet coil system (14) which generates a homogeneous magnetic field of at least 3T, and a gradient coil system (15) which generates a gradient strength of at least 10 mTm−1, with a slew rate of at least 100 Tm−1s−1, wherein the main field magnet coil system (14) is arranged in a cryostat (12) with liquid helium and a refrigerator (16) in the form of a pulse tube cooler or a Gifford-McMahon cooler, and wherein an evaporation line (17a, 27a, 37a) is provided for helium that might evaporate from the cryostat. In all states of operation of the NMR apparatus (10) without gradient switching, the refrigerator provides a cooling capacity which is at least 0.3 W above the overall power loss of the cryostat, the evaporation line terminates in a buffer container (19, 29, 39, 39′) disposed outside of the cryostat for collecting the evaporating helium, and a return line (17b, 27b, 37b) is provided for returning the evaporated helium that has been collected in the buffer container into the cryostat. For this reason, a considerable amount of evaporating helium is saved, thereby considerably extending the ref…