IN-SITU CHARACTERIZATION OF MICRON-SCALE PARTICLES BY NUCLEAR MICROSCOPY

Nuclear microscopy is well suited for analyzing large particle populat ions as well as individual particles of interest in various types of c ollection samples. Unlike some commonly used in situ techniques, nucle ar microscopy can quantitatively characterize particles embedded withi n the sample or particles that are too small to be reliably removed fr om their collection media. Additional advantages include its capabilit y for the detection of minor and trace elements, its capability to sim ultaneously analyze multiple elements with little or no prior sample p reparation, and its potential for automated analyses. Preliminary data are presented of particle size and composition measurements conducted on air filters. The potential of applying nuclear microscopy to the c ataloging of micron-scale cometary remnants captured in low density ae rogel collectors is also explored. Because of its importance to a vari ety of collection programs, an innovative high-throughput ion beam ima ging and analysis system is being jointly developed by Sandia and Lawr ence Livermore national laboratories for rapid quantitative particle c haracterization. (C) 1997 Elsevier Science B.V.