Apparatus and method for controlling ion beam properties using energy filter

A method for controlling an ion beam, comprising:

• directing the ion beam through an electrode assembly of an electrostatic lens, the electrode assembly comprising a plurality of electrodes;
• assigning a plurality of electrode voltages to the plurality of electrodes, wherein the plurality of electrode voltages define a first deceleration length in a first operating mode for a first ion beam having a first perveance;
• and
• decreasing the first deceleration length of the electrode assembly in a second operating mode for a second ion beam having a second perveance, greater than the first perveance.

A method for controlling an ion beam, comprising:

• directing the ion beam through an electrode assembly of an electrostatic lens, the electrode assembly comprising a plurality of electrodes;
• assigning a plurality of unadjusted electrode voltages to the plurality of electrodes in order to conduct the ion beam along an arc defining a nominal central ray trajectory;
• and
• adjusting the plurality of unadjusted electrode voltages to a set of adjusted electrode voltages, wherein an actual beam path deviates from the nominal central ray trajectory, wherein at least one beam feature of the ion beam is altered.