| 摘要 |
<p>An ion gun (42) for producing a pulsed microfocused beam of ions comprises an ion source (1) arranged to produce a continuous ion beam along a z-axis toward a collector (13) having an aperture (14) on the axis. A deflector (7) is arranged to maintain the beam substantially stationary and incident on the aperture for a pulse time, to deflect the beam away from the aperture to the collector and subsequently to return the beam to be incident at the aperture. A focussing lens (15) focusses the beam from the deflection point (at 7) to a final image point, and a condensing lens (2) focusses the beam at the deflection point. A mass filter (6) selects a single ion species, and a second deflector (10) deflects the beam orthogonally to the deflector (7) so that the returning path of the beam on the collector (13) does not cross the aperture (14). A stigmator (60,61) and a beam scanner (19) are also provided.</p> |
