The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 02, 2002
Filed:
Dec. 03, 1998
Karel D. van der Mast, Helmond, NL;
Philips Electron Optics B.V., Eindhovem, NL;
Abstract
The current of secondary electrons emanating from the specimen in an ESEM is amplified by an avalanche-like ionization of the molecules of the gas atmosphere. However, in order to achieve an adequate number of successive ionizations, a comparatively high voltage is required at the detector electrode and, because of the risk of electric breakdowns, the distance between the specimen and the detector may not be smaller than a comparatively large minimum distance. Consequently, the number of successive ionizations is limited and hence also the current amplification. In order to achieve a higher amplification, the invention proposes the application of an additional magnetic field B in the ionization space. The path length of the secondary electrons is thus substantially increased so that a significantly larger number of ionizations takes place and hence a higher amplification is achieved.