Study on Dipole Moment in Permanent Magnet Used in Space Anti-Matter Detector

The dipole moment in the space anti-matter detector AMS01 magnet has been studied. A compensating method for the dipole moment in AMS01 was developed. The theoretical analysis and experimental test of 1/3 model magnet showed that the N47 NdFeB permanent magnetic material can compensate the dipole moment in 1000 Am with weight about 7 kg. A new testing method for the dipole moment of large scale AMS01 magnet is proposed. On the basis of the method, the measurement of the dipole moment in the AMS01 is about 11550 Am2 plusmn 10%. The finite element calculation by ANSOFT is about 7300 Am . The difference between theory and experiment may come from the experiment environment, friction torque or the demagnetization of the magnet. It proves that the permanent magnetic block with high magnetic energy product to compensate the dipole moment is an effective method. The permanent magnetic block with magnetic energy product about 230.4 kj/m³ can compensate about 740 Am plusmn 20% of dipole moment. The compensating permanent block magnet has a little effort on the central magnetic field and uniformity in the AMS01.