Page 172 - Inorganic Mass Spectrometry - Fundamentals and Applications

162 Cristy

SLIT

First ion microscope of Castaing and Slodzian. (From Ref. 18.)

tected in a manner similar to that described by Bernhard et al. [26]. Isotope de-
flector plates (Fig. 4.6) between the secondary magnet and the detector slit allowed
rapid sweeping of the secondary ions across the detector slit. Mass resolution was
on the order of 600.
In 1965 Long published a proposed ion microprobe analyzer [27]. Long's
student, Drummond, began construction and in 1967 published secondary electron
micrographs showing 0.5-pm resolution C281 using a primary beam column. This
became the basis for the Associated Electrical Industries (AEI) Ltd. SIMS instru-
ment [29]. This instrument utilized AEI's MS702R spark source mass spectrome-
ter for secondary ion analysis and had a mass resolution -5000,
of
Hitachi announced the development of the third commercial microprobe in-
the
s~~ment, ion microprobe analyzer IMA-2 in 1969 [30]. This instru~ent placed
a scintillator close to the sample for secondary electron imaging. A Wen filter, for
primary beam mass selection [3 l], and an electron spray, for charge compensation
on insulating samples [32], were added later.
of
In 1969 Benninghoven introduced the concept static SMS for the deter-
mination of the chemical composition of the uppermost monolayer of a material
[33]. This technique required ultrahigh vacuum conditions and very low primary
beam currents, A/cm2, so that less than 1% of the surface was removed dur-