Development of 3D-printed diffusion camera for Alpha Track detectors

Radon long-term detectors are the most suitable choice to ascertain the concentration of radon indoors. These devices are usually composed of a diffusion chamber housing an Alpha Track or Solid State Nuclear Track detector. However, the diffusion cameras on the market for these detectors are very limited or unavailable. Thus, this work proposed an alternative for the manufacture of the diffusion chambers used to place the Alpha Track detector, type CR-39. The model of the camera was made in CAD software called Inventor Professional (version 2021), developed by Autodesk company. The model was printed on a 3D printer, manufactured by GT Max company (Core AB400 model) that uses roll filament. In this case, the material used was Acrylonitrile Butadiene Estyrene (Abs), provided by 3D Fila company. To assess the efficiency of the new chambers, they were subjected to a test carried out inside a sealed 101.1 L container. In the container were placed the new chambers (Abs), the traditional chambers (polyethylene), a source of Radio-226 with activity of 3.379 kBq/m³, and an factory-calibrated Alpha Guard detector (AG), for 48 hours. The manufacture of the cameras through the 3D printer was carried out successfully and at a suitable time for reproduction. In the first test, the radon concentration measured by the 3D chambers ranged from 9.98 to 15.41 kBq/m³, with a mean value of 14.04 kBq/m³. In the traditional chambers, the radon concentration ranged from 10.61 to 12.53 kBq/m³, with an average of 11.56 kBq/m³. In the second test, the radon concentration for the 3D chambers ranged from 15.46 to 19.88 kBq/m³, with an average of 17.46 kBq/m³, and in the traditional chambers, the radon concentration ranged from 12.25 to 14.65 kBq/m³, with an average of 13.77 kBq/m³. Moreover, in the first and second tests, the mean radon concentration registered by the AG reference detector was 17.18 and 19.95 kBq/m³, respectively. It is concluded that when comparing the radon concentration measurements obtained from each type of chambers, both have similar results; however, the 3D chambers recorded a greater number of traces, which may indicate more permeability of the material. To ensure the the reliability of results of the 3D-printed chambers, it is necessary to make a specific calibration curve for these chambers. (author)