A gamma ray tomography system was designed, developed and employed for the
measurement of radial hold-up profiles in bubble columns. Measurements were
of gamma ray attenuation. For the given source strength the collimator des
igns for both source and detectors were optimized to Set the maximum number
of counts with the least scattering effects. For the given dwell and scann
ing times, excellent reproducibility was obtained. Both fan beam and pencil
beam scanning were employed to minimize the error due to scattering of the
photons near to the wall regions. Experiments were performed in a 0.385 m
internal diameter bubble column. Chordal hold-up profiles were used to find
the radial hold-up profile using Abel's inversion method. (C) 2001 Elsevie
r Science B.V. All rights reserved.