Page 117 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

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holdup over the volume of the packing, the tomography method is presented. In
different variants of the method x-rays [92] or y-rays [87, 93-99] are used. The
gamma method is especially useful for investigations of industrial column
damages.
In detail the investigations using this method are described by Wang et
al. [100]. The experimental installation is similar to that presented in Fig. 2.
Additionally it includes a gamma-ray emitting and detecting system, presented
in Fig. 12, mounted around the column on the investigation plane.

Source head Track

Sienai Detector
amp ifier
1—
Power
H —•»» |S£r)

Data collecting Terminal
system controller

Fig. 12. Sketch of a gamma-ray emitting and detecting system.

When the gamma-ray passes through a medium, its intensity is reduced
from I o to / due to absorption of the radiation flux by the medium. The
relationship between land /„ is given by the low of Beer-Lambert