SURFACE AND MICROCHEMICAL ANALYSIS WITH MEV IONS.
Academic Article
Overview
Additional Document Info
View All
Overview
abstract
Two physicochemical characterization techniques using only a few tens to hundreds of heavy ions/sec are described: absorptiometry and particle desorption mass spectrometry (PDMS). Absorptiometry with 39. 8 MeV **8**4Kr ions, measuring energy loss via time-of-flight (TOF), allows determination of carbon foil thickness variations 24 90 Angstrom. The measurements can be made with a microbeam (approximately 1 mu m) with sensitivity to mass differences of approximately 10** minus **1**4 g. PDMS presents novel possibilities for characterizing surfaces of insulators. The technique is based on the desorption of atomic and molecular species from surfaces bombarded by fast heavy ions (produced by an accelerator or fission fragments of cf-252). By identifying the desorbed species via TOF-MS, comprehensive inorganic and organic analysis is feasible. Detection limits of 10** minus **2% atomic have been obtained. The technique can be applied in the microprobe mode by collimating the bombarding ion beam. Multimass analysis has been demonstrated on spots of 11 mu m diameter.
