Magnet system with shielded regenerator material

US7005953B2 · kind B2 · utility

Assignee

• Bruker Biospin GmbH · DE

Inventors

• Pierre-Alain Bovier · Zürich, CH
• Patrik Vonlanthen · Schwerzenbach, CH
• Andreas Kraus · Waldenbuch, DE

Key dates

• Filing date: Apr 26, 2005
• Grant date: Feb 28, 2006
• Expiry date: Apr 26, 2025

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F25B2309/1415
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A magnet system with a magnet arrangement (M), a working volume (V) and a pulse tube cooler (P) with magnetic regenerator material (r) is characterized in that a shielding (m) of magnetic material is provided which reduces the stray field of the magnet arrangement at the location of the magnetic regenerator material (r) and is characterized in that⅓|{tilde over (m)}RegR|+|mMagΔx|<⅙|mRegR|, wherein mMag is the dipole moment of the magnetic material of the shielding (m), Δχ is the vibration amplitude of the magnetic material of the shielding (m), mReg is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle without magnetic shielding (m), {tilde over (m)}Reg is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle with magnetic shielding (m), and R is the average separation of the magnetic regenerator material (r) from the working volume (V). A magnet system of this type has an optimum stable, temporally constant magnetic field in the working volume (V).