Patent ID: 6809322
Filing Date: 2004-10-26
Classification: H01J

Abstract:
A device using electron optical means for the generation and propagation of a focused charged particle beam transferred via two apertures from a high vacuum chamber into a low gas pressure specimen chamber with an intermediate pressure chamber there between, said apertures being aligned along axis of said beam, and characterized in that:(a) said beam is deflected and scanned by a set of scanning coils situated near said axis of said beam; (b) all of said coils being substantially between said two apertures; (c) amplitude of the deflection of said beam inside the specimen chamber is larger than the diameter of the aperture separating the specimen chamber from the intermediate pressure chamber; (d) the aperture separating the specimen chamber from the intermediate pressure chamber is located substantially at the end of the electron optical means, or away from the end of the electron optical means to allow a specimen to be freely placed without obstruction at any distance from the aperture (e) wherein the said aperture that separates the specimen chamber from intermediate pressure chamber incorporates a pair of apertures having additional pumping means evacuating the space formed between the said pair of apertures.