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:
Oct. 16, 2007
Filed:
Apr. 20, 2005
Eizo Kawato, Kyoto-fu, JP;
Eizo Kawato, Kyoto-fu, JP;
Shimadzu Corporation, Kyoto, JP;
Abstract
The method of the present invention is to select ions having a predetermined mass to charge ratio by applying an ion selecting electric field in an ion storage space of an ion storage device. The method is characterized in that the ion selecting electric field is generated to be proportional to a product of a) a base wave composed of a repetition of a unit wave of a constant amplitude and a predetermined pattern, and b) an amplitude pattern which changes continuously. The amplitude pattern is preferred to increase as time passes in order to gradually increase the intensity of the ion selecting electric field applied to the ion storage space until ions of a desired mass to charge ratio are selected. The unit wave may be generated by the FNF method or by the SWIFT method. Further, it is effective to increase the intensity of the frequency components of the unit wave as the frequency is further from the characteristic frequency of the object ion having a desired mass to charge ratio.