This work presents the progress in the development and simulation of solid-state microdosimeters based on semiconductor PIN diodes, intended for use in proton therapy. These devices are designed and microfabricated at the Comisión Nacional de Energía Atómica (CNEA, Argentina), in collaboration with international institutions such as CTN-IST (Portugal). Microdosimeters measure radiation doses at micrometric scales and offer advantages over conventional tissue-equivalent proportional counters (TEPCs), such as compact size, low operation voltage, high spatial resolution (∼10 µm), and ease of integration.1, 2 The proposed devices consist of spatially distributed matrices of PIN photodiodes with guard rings, tailored to mimic biological cell distributions for improved relevance in radiotherapy contexts. Our research focuses on two parallel lines of microdosimeter development: one based on silicon and another based on gallium arsenide (GaAs). While the silicon-based microdosimeters are currently more advanced in terms of fabrication and simulation, the GaAs-based devices are also actively being developed, with ongoing efforts in both the microfabrication and testing stages.3 These devices are fabricated using Molecular Beam Epitaxy (MBE), a technique that enables precise control over layer composition and doping. Their production involves extensive use of cleanroom facilities at our institution. GaAs offers unique advantages such as higher electron mobility, superior radiation hardness, and a direct bandgap, all of which contribute to improved signal-to-noise ratio and performance under high-dose or high-rate radiation environments. Final device characterization will validate performance for its intended medical applications.
Mercado et al. (Thu,) studied this question.