Thomas P Rusch

US Patent:

39379582, Feb 10, 1976

Filed:

Mar 31, 1975

Appl. No.:

5/563330

Inventors:

Thomas W. Rusch - Falcon Heights MN
Jerry A. Sievers - Stillwater MN

Assignee:

Minnesota Mining and Manufacturing Company - St. Paul MN

International Classification:

H01J 3726

US Classification:

250307

Abstract:

A charged particle beam (e. g. , ions or electrons) apparatus including two electrostatic focusing lenses and an electrode having a diameter limiting aperture positioned between the lenses is further provided with two electrode assemblies which interact with an extractor electrode and with a source of charged particles such that the trajectories of the particles in the beam passing through the second of the two assemblies are substantially parallel. This feature and other disclosed improvements facilitate the production of a substantially monoenergetic beam which under a first set of conditions can be focused to provide a small-diameter, spherical-aberration limited beam and which under another set of conditions, can be focused to provide a high current beam.

US Patent:

41075269, Aug 15, 1978

Filed:

Jan 12, 1977

Appl. No.:

5/758836

Inventors:

James T. McKinney - Stillwater MN
Thomas W. Rusch - Falcon Heights MN

Assignee:

Minnesota Mining and Manufacturing Company - St. Paul MN

International Classification:

H01J 3500

US Classification:

250305

Abstract:

An ion scattering spectrometer (ISS) providing enhanced sensitivity, reduced background, and preferential detection of low-mass scattered ions over that of high-mass sputtered ions is disclosed. These advantages are accomplished by a biasing arrangement which maintains a potential difference between the analyzer exit and the detector input at less than 30 volts and substantially eliminates the high potential provided on detector inputs of prior art ion scattering spectrometers which attracted and thereby accelerated ions prior to impinging on the inputs.