Bio-magnetic separation system with double ring distribution

The invention relates to a biological magnetic separation system which comprises an outer ring and an inner ring of a permanent magnet, the outer ring is a quadrupole Halbach cylinder, and the inner ring is a Halbach cylinder with N magnetic poles. The diameters and other conditions of these cylinders are selected such that the magnetic field gradient at the container wall is greater over the inner radius of the inner ring than when only the outer ring. 本发明涉及一种生物磁分离系统，包括永磁体的外环和内环，外环是四极Halbach圆筒，内环是具有N个磁极的Halbach圆筒。这些圆筒的直径和其它条件被选择为使得在内环的内半径上，容器壁处的磁场梯度大于仅外环时的磁场梯度。