Achromatic Magnetic Omega-Filter with an Internal Mass Selection

A new configuration is proposed for a magnetic Omega-filter with achromatic beam transport and the possibility of ion mass separation at an aperture slit in the middle of the filter. Dipole sector magnets with 160-deg deflection angles, together with electrostatic multipoles at the entrance and exit of the filter, are used in the Omega-filter to form the ion beam and correct angular aberrations. With ions pre-cooled in a radiofrequency quadrupole, a mass resolving power exceeding 2000 can be achieved at full transmission of the phase volume of the ion beam.