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In optical tomography of parallel projections, the light rays that cross the slice of the
object are experimentally approached to suffer minimal refraction, i.e. take refractional limits.
Generally, a media is used for immersion whose refractive index rate tied the environment to
study, but the geometry of the containment vessels also affects refraction and may be the case
that the approach is not subject performed. In this work we make a numerical study of the
refraction of a ray of light that enters a typical experimental system for studying the
thermodynamic behaviour of a paraffinic wax around their cloud point. Since it has special
properties in the heat capacity and refractive index near the phase transition, these results will
be used to characterize the transition and is intended to give tomographic information to the
study of thermal properties obtained using the T-History calorimetric technique. In this study,
we simulate the behaviour of the refraction of parallel rays crossing the T-History test system
to find the optimal values of the dimensions of the containment vessels and the index of
refraction of the medium for immersion, considering that the optical properties of the sample
under study vary with temperature. Thus, we obtain the optimum conditions of minimum
refraction technique for which reconstruction of a tomographic slice parallel projection can be
applied. The distribution of the linear attenuation coefficient on the slice of the object,
typically, is obtained by applying the filtered backprojection algorithm to the set of projections
(sinogram) obtained experimentally, which constitutes a way to detect mobile interfacial
boundaries in real time. The projections are sequentially measuring the intensity of the wave
emerging from the slice of the object at different angles.
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