  The Fast Aerosol Spectrometer (FASP) is a device for spectral aerosol
measurements. Its purpose is to safely monitor the atmosphere inside a reactor
containment. First we describe the FASP and explain its basic physical laws.
Then we introduce our reconstruction methods for aerosol particle size
distributions designed for the FASP. We extend known existence results for
constrained Tikhonov regularization by uniqueness criteria and use those to
generate reasonable models for the size distributions. We apply a Bayesian
model-selection framework on these pre-generated models. We compare our
algorithm with classical inversion methods using simulated measurements. We
then extend our reconstruction algorithm for two-component aerosols, so that we
can simultaneously retrieve their particle-size distributions and unknown
volume fractions of their two components. Finally we present the results of a
numerical study for the extended algorithm.
