| CPC H01J 37/261 (2013.01) [H01J 37/28 (2013.01); H01J 2237/2801 (2013.01)] | 19 Claims |

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1. A stage apparatus, comprising:
a short stroke stage;
a long stroke stage;
a sensor configured to measure a position of the short stroke stage with respect to a measurement reference, arranged on a frame of a system configured to use the stage apparatus to position an object, not on the short stroke stage and not on the long stroke stage;
one or more roller bearings configured to support the long stroke stage; and
a controller for controlling a motion of the long stroke stage and a motion of the short stroke stage for following movement of the measurement reference based on a position measurement from the sensor, wherein the controller is configured to control the motion of the long stroke stage according to selectable modes of operation to reduce debris generation by the one or more roller bearings, wherein the selectable modes comprise:
a coupled mode, wherein the control of the long stroke stage is coupled to the movement of the measurement reference based on the position measurement from the sensor; and
a decoupled mode, wherein the control of the long stroke stage is decoupled from the movement of the measurement reference to reduce a movement of the one or more roller bearings.
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