HELICAL UNDULATOR

摘要

The invention provides a helical undulator of a permanent magnet capable of minutely adjusting a magnetic field. In this invention, four permanent magnets are arrayed for their magnetism directions to be changed by 90 degrees on a cylinder of non-magnetic metal having a number of holes. By adjusting the height of the magnets of which magnetisms are in the direction of an undulator axis, the magnetic field can be minutely adjusted.