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:
Jun. 20, 1995
Filed:
Mar. 09, 1994
Yoshitomo Nakagawa, Tokyo, JP;
Tetsumasa Itoh, Tokyo, JP;
Seiko Instruments Inc., Tokyo, JP;
Abstract
An object of the present invention is to provide a detection system wherein ion counting is performed by varying the quantity of the ions incident on a detector 13 of an inductive plasma mass spectrometer depending on the concentration of the impurities to be measured, thereby extending the life of the detector 13, expanding the range for measurement of impurities in high concentrations, and reducing costs. An assist electrode 30 having a hole for leading the ions which have passed through a mass filter 10 to a detector 30 is disposed between the axis of the mass filter 10 and the detector 13, and a means for applying voltage to a repeller electrode 12 and the assist electrode 30 is provided to vary the difference in voltage between the electrodes 12 and 30 depending on the concentration of impurities to be measured. When the concentration of the impurities to be measured is high, the difference in electric potential between the repeller electrode 12 and the assist electrode 30 is made greater than the difference in electric potential set for measurement at low concentrations. The life of the detector is extended, high impurity concentrations of up to six digits can be measured, and an inexpensive detection system is provided.