The nuclear microprobe is an instrument of elemental microanalysis, wi
th imaging capabilities, particularly suitable for the measurement of
trace elements in biological tissues. It makes use of the numerous typ
es of emitted radiations resulting from the interaction of MeV charged
particles with the matter. Particle Induced X-ray Emission, Rutherfor
d Backscattering Spectrometry, Nuclear Reaction Analysis and Scanning
Transmission Ion Microscopy are analysis or imaging techniques which c
an be simultaneously carried out using a particle microbeam. The analy
sis may be routinely achieved at the part per million level of sensiti
vity, the micron spatial resolution and in multi-elemental mode. In ad
dition, the combination of elemental mapping with high resolution STIM
imaging allows the technique to provide a wealth of useful informatio
n on the sample under investigation. This paper is an introduction to
ion beam technique of microanalysis. Basic principles are briefly disc
ussed as well as practical aspects concerning the sample preparation a
nd the beam damages.