| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnet system having a pulse tube refrigerator provided with a magnetic heat regenerating material, and capable of realizing a time-serially fixed magnetic field with the optimum stability in a working volume. SOLUTION: This system is provided with a magnetic shielding material to reduce a stray magnetic field of a magnetic arrangement in a position of the magnetic heat regenerating material, and is characterized by Expression 1, where m<SB>Mag</SB>is a dipole moment of the magnetic material of a shield,Δχis a vibration amplitude of the magnetic material, a m<SB>Reg</SB>is a dipole moment fluctuation amplitude of the magnetic heat regenerating material in one cycle in the absence of the magnetic shielding material, Expression 2 is a dipole moment fluctuation amplitude of the magnetic heat regenerating material in one cycle in the presence of the magnetic shielding material, and R is an average separate distance of the magnetic heat regenerating material r from the working volume V. COPYRIGHT: (C)2006,JPO&NCIPI |
