Device for the ionization of metals having a high melting point, which may be used on ion implanters of the type using ion sources of Freeman or similar type

An ion implanter using a Freeman-type ion source, comprising:

• a cylindrical casing provided with an internal cavity having a longitudinal axis,
• an arc chamber superimposed over said cylindrical casing and having an external casing held at a positive voltage,
• an electrical filament housed in said arc chamber and connected to an electrical current supply,
• a repeller plate housed in said arc chamber in front of said filament and held at a first negative voltage with respect to the external casing of said arc chamber,
• a gas inlet for feeding an ionizable gas into said chamber and,
• a support for a metal to be ionized which is housed in said arc chamber in a location intermediate between said filament and said repeller plate and out of the electron flow emerging from the filament and is electrically connected to an electrode held at a second negative voltage lower than said first negative voltage.