Patent ID: 7544952

Claim:
A source of generating multicharged ions, including: an ion source electrode comprising an electron source, a drift tube that constitutes an ion trapping region and a collector; a superconducting magnet for ion entrapment; and an ion infeed means,characterized in that it further includes: a first vacuum chamber receiving said ion source electrode; a second vacuum chamber receiving said superconducting magnet; wherein said first vacuum chamber is disposed by being passed through said second vacuum chamber, a vacuum pumping means are provided to said first and said second vacuum chambers, respectively, a first magnetic shield is provided in a peripheral area of the second vacuum chamber on the first vacuum chamber side so that the magnetic field by said superconducting magnet does not leak to the electron source of said ion source electrode and said drift tube of the collector side, at least the opposing surfaces of said first and second vacuum chambers are formed with a nonmagnetic material so that the magnetic field by said superconducting magnet is applied to said drift tube, and the electron source of the ion source electrode in said first vacuum chamber is received in a second magnetic shield part.