ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
We report on the design, construction, and magnetic field measurements of a system of high field sextupole magnets made from NdFeB compounds. The magnets are utilized as a focusing system for neutral hydrogen (or deuterium) atoms in a polarized atomic beam source based on Stern–Gerlach spin separation. Each magnet consists of 24 segments of permanently magnetized material differing in remanence and coercivity to reduce demagnetization. According to quadratic extrapolation to the pole tip the magnetic flux density reaches values of up to B0=1.69 T. Three-dimensional field calculations using the MAFIA code were carried out to optimize the magnet performance and to avoid demagnetization by selecting appropriate materials for the individual segments. Measurements of the radial, azimuthal, and longitudinal magnetic flux density distributions were carried out by means of a small Hall probe (100×200×15 μm3). The measurements with the small probe permitted to extract experimentally higher order multipole components very close (∼100 μm) to the inner surface. Experimental values obtained are compared to predictions based on MAFIA calculations and on the Halbach formalism. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1288264
Permalink