The Physics of a Disinfector With UV–C Radiation

In this article, we discuss the physics involved in a ultraviolet–C (UV–C) radiation chamber used for disinfection of surfaces and objects, in the context of the COVID–19 pandemic. When exposed to UV–C radiation, viral RNA change its molecular structure, a process caused by a rearrangement in the nitrogenous basis, inactivating the virus, and preventing reproduction. We propose the construction of a UV–C chamber using materials that are accessible to the population, with security features. We also discuss the design process in determining the distance and exposition time needed for the appropriate UV–C dose. Theoretical correction factors are also used, in order to account for factors that make our approximations more realistic in terms of the geometry of the system. Experimentally, the lamp used for the prototype was tested, obtaining a power in UV–C range of P_uv = 171μ W, after corrections. Exposition times were then defined, ranging from 20–90 minutes, considering distances from 5–36 cm from the objects to the lamp.

Keywords
COVID-19; Ultraviolet-C; Optics; Disinfectant