GB1026102A - Mass spectrometers - Google Patents

Abstract

1,026,102. Mass spectrometers. WESTINGHOUSE ELECTRIC CORPORATION. June 24, 1963, No. 25080/63. Heading H1D. A mass spectrometer includes between the ion source and the photographic detecting plate a monitoring electrode having a slit varying in area across the ion path in order to extend the range of ion intensity measurements for one exposure of the photographic plate, the recorded intensity, e.g. varying in geometrical progression along one dimension of the photographic surface. The system may also be used for analysing the deposition of isotopic components. The slit may have stepped edges 217, Fig. 7 (not shown), or curved edges, Fig. 8 (not shown), or the slit may be constituted by two slots 233, 235, Fig. 9 (not shown), of varying width or by a convex or concave mesh grid, Fig. 10 (not shown). The monitoring electrode may be of tantalum and formed in two halves joined together by welded platinum strips. The spectrometer includes a spark type ion source, the electrodes E1, E2, Fig. 2B, being adjustably mounted by means of bellows mechanisms including swivel joints, rotatable nuts and sideways translating devices, a beam collimator system constituted by apertured plates 145, 148 and 151, an electrostatic analyser comprising curved plate electrodes 173 mounted on glass blocks 177, the monitoring electrode 201, a magnetic analyser in which the magnetic polepieces form the side walls of a housing, and a photographic plate assembly comprising a holder, a backing plate and a displacing mechanism. An electron beam bombardment ion source may be used instead of the spark type source.