For a given extraction voltage and magnetic flux density, the r is proportional to square root of mass and thus ions of any particular mass can be selected by appropriately placing an exit slit. The collimators filter a stream of rays so that only those travelling parallel to a specified direction are allowed through. They help to shape the beam of radiation emerging from the machine and can limit the maximum field size of a beam. The surviving ions move into the accelerator tube where the ion beams gets energised under the very high acceleration potential. The output of the tube is usually maintained at ground potential for safety reasons.

In order to implant in the x and y directions the wafer surface, electrostatic and mechanical beam scanning techniques are used. The electrostatic scanning in both x and y directions is the simplest, and has advantage of very high scanning speed. However, when the beam voltages are 50 keV or higher, beam expansion (blow up) takes place and so mechanical scanning is usually used. In the mechanical scanning system the beam is stationary and the substrate wafer is moved.