(19)

(11)

EP 0 509 986 A1

(12)

(43) Date of publication: 28.10.1992 Bulletin 1992/44 (21) Application number: 90903006.0 (22) Date of filing: 08.01.1990

(51) International Patent Classification (IPC):  H01J 49/ 26( . ) H01J 49/ 42( . ) (86) International application number: PCT/EP1990/000030 (87) International publication number: WO 1991/011016 (25.07.1991 Gazette 1991/17)

(84) Designated Contracting States: DE GB (71) Applicant: Bruker-Franzen Analytik GmbH D-28359 Bremen (DE)	(72) Inventor: WANG, Yang D-2800 Bremen (DE) (74) Representative: KOHLER SCHMID + PARTNER  Patentanwälte Ruppmannstrasse 27 D-70565 Stuttgart D-70565 Stuttgart (DE)