3D-Printing of Ionization Chamber Detectors for Dose Variance Measurements

Sammanfattning

This thesis work investigates the possibility of 3-D printing an ionization chamber for use in the field of microdosimetry. The aim is to achieve a proof of concept with a detector printed with a combination of conductive and non-conductive materials. The design can then be coupled with existing electronics to provide radiation measurements. In addition to printing a working detector, the work aims to suggest potential design changes in geometry and dimensioning. A spherical detector was designed and printed using PLA and Conductive PLA filaments. The diameter of the active region is approximately 5 cm, while the entire detector with stem is 11 cm tall, with a wall thickness is 3 mm. The printed detector was equipped with a BNC cable and banana connectors to be coupled with electronics. Measurements were performed with the detector at the Swedish Radiation Safety Authority, with the goal of using the variance method for determining dose mean lineal energy at the micrometer scale. Under irradiation from a cesium-137 source, the variance method gave a dose mean lineal energy of 0.685 ± 0.055 keV/μm for cesium-137 in a simulated site diameter of 53 μm. This is in line with literature values obtained with commercial detectors. The dose rate was also calculated to validate the performance of the detector. This study will give a basis for the use of such 3-D printed models in the field of micro- and nanodosimetry.