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.

Date of Patent:
Feb. 29, 2000

Filed:

Oct. 03, 1996
Applicant:
Inventors:

Shinichi Takada, Chiba, JP;

Yoshitomo Nakagawa, Chiba, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N / ; H01J / ; B01D / ;
U.S. Cl.
CPC ...
324466 ; 324459 ; 324464 ; 250281 ; 250294 ;
Abstract

A mechanism is provided for reducing contamination of the interior of an apparatus by a sample and for performing a stable measurement. An ion lens has an Einzel lens for converging an ion beam, a deflector for deflecting the ion beam and a pair of compensation electrodes each composed of one or more elements. A mechanism is provided for controlling a voltage to be applied to each of the electrodes as desired. Also, alternatively, a shield plate is provided in a flow path of the ion beam. A drive mechanism is provided for projecting and retracting the shield plate. With such an arrangement, it is possible not only to effectively detect a small amount of impurities contained in a sample but also to stably measure the concentration thereof.


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