Wien filter

The beamline is equipped with three velocity filters. Those so-called Wien filter use an electric field E and a perpendicular magnetic field B to select only ions with the desired velocity v. Only those ions, for which the equilibrium condition of Lorentz and electrical force

q⋅v⋅b = q⋅E

holds, can pass a slit installed after the filter. Since the magnetic rigidity

B⋅r = m⋅v/q

of the ions is set by the 90° Analyzing Magnet located after the accelerator, the selection of a defined velocity leads to the suppression of the isotopic background for a given charge state q. Thus, it is possible to state a mass resolution of the Wien filter, which is determined experimentally. The best resolution of ΔM/M = 1/120 is obtained with the third Wien filter installed in the Actinid beamline.