CONSTRUÇÃO DE UM DETECTOR DE IONIZAÇÃO GASOSA COM MATERIAL DE BAIXO CUSTO PARA PRÁTICAS EXPERIMENTAIS NO ENSINO DE FÍSICA NUCLEAR

Abstract

One of the difficulties in modern physics teaching is the little widespread of experimental activities. This is particularly true for teaching nuclear physics in Brazilian high school or college. The activities suggested in the literature generally symbolize the real phenomenon, using simulations. This happens because the experimental practices mostly include some kind of expensive radiation detector and an ionizing radiation source that requires special care for handling and storage, being subject to a highly bureaucratic regulation in Brazil. This work overcomes these difficulties and propose three nuclear physics experiments using a low-cost ion chamber, which construction is explained: the measurement of Radon-222 progeny collected from the indoor air; the measurement of the range of alpha particles emitted by the Thorium-232 daughters, present in lantern mantles, and by an Americium-241 source, taken off from a smoke detector; and the measurement of Radon-220 half-life colected from the emanation of the lantern mantles. The article presents the experimental procedure and the expected results, indicating that the experiments may provide support for nuclear physics classes. These practices may outreach wide access to either college or high-school didactic laboratories. In order to verify the viability of the ion chamber construction by working teachers, and the applicability of the didactic experiments, they were presented to teachers of public schools, and a didactic proposal was implemented to second year high-school students of a private school located in Guarapuava, Paraná State, Brazil. Both, teachers and student, were capable to work on the experiments. The ion chamber proved to be sufficient sensible and stable, and the experiments executed by the teachers and students show adequate results. This confirms their practicability and their potential for the development of new teaching activities for nuclear physics.