The Magnet

The magnet, shown in Figure 1 and 2, is made of 64 high-grade Nd-Fe-B sectors assembled in a cylindrical shell structure 0.8 m long with an inner diameter of 1.1 m. This configuration produces a field of 1.4 kG in the $x$ direction at the center of the magnet and negligible dipole moment outside the magnet. This is important in order to eliminate the effect of torque on the Space Station. Figure 3 shows the detailed three-dimensional field of the magnet mapped in 2010. The field was measured in 120 000 locations to an accuracy of better than 1%. Comparison with the measurements performed with the same magnet in 1997, before the engineering flight of AMS-01, shows that the field did not change within 1%, limited by the accuracy of the 1997 measurement. Together with the tracker, the magnet provides a maximum detectable rigidity of 2 TV on average, over tracker planes 1-9, where rigidity is the momentum divided by the charge. Figure 4 and Figure 5 show the vibration test and static load test carried out in 1996 in China.

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Figure 1. Magnet System: 10 magnets were made, 7 to ensure that the magnet has no torque or field leakage, and can be constructed without iron. Three full size magnets for space qualification, destructive test and flight.
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Figure 2. The magnet.
3D field map.
Figure 3. The detailed 3D field map (120k locations) was measured in May 2010, which shows that the deviation from the 1997 measurement had remained the same to <1%
Magnet test
Figure 4. Preparing for the vibration test in China Academy of Launch Vehicle Technology (CALT)
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Figure 5. Static load test in China First Heavy Industries (CFHI).