Experimental Analysis of Temperature Evolution in a Gamma Irradiation Chamber Cooled with Dry Ice

Abstract

The main objective of this work was to develop a first-approximate method for determining the ideal amount of dry ice required to preserve biological samples below -5 °C during gamma irradiation processes in a self-shielded irradiator, ensuring their frozen state. To this end, four experiments were conducted in which the mass and spatial distribution of dry ice within a sample holder used in an irradiator were varied, and the temperature at the center of the holder was measured and recorded for approximately 30 hours. From this, the time during which the temperature remained below -5 °C was determined, and a linear model was constructed using least squares to relate mass to thermal preservation time. Furthermore, it was determined that mass and its distribution are crucial factors for improving thermal control in gamma irradiators.