Characterization of Crystalline CsPbBr3 Perovksite Dosimeters for Clinical Radiotherapy

Lead halide perovskite CsPbBr3 is a wide-gap semiconductor material potentially very attractive for next generations of real-time monitors and particle detectors in high-energy physics. Here, we present the first characterization of crystalline CsPbBr3 point dosimeters with submillimeter size, under 6 MV X-photon beams used in clinical radiotherapy. Current response of the devices proved to be promising in terms of fast rise and decay times, of the same order of the X-ray beam onset and offset ones; absence of polarization effects; reproducibility to repeated irradiations; and linearity of the collected charge as a function of the absorbed dose. Comparing the measured sensitivity with the theoretical one, a charge collection distance of about 100 mu m has been evaluated, of the same order of the linear dimensions of crystallites within the samples, suggesting that recombination centers are mainly placed at grain boundaries. A much higher sensitivity per unit area measured with crystalline CsPbBr3 as compared with drop-casted ones can be explained in terms of a less disordered crystalline structure. This work opens the way to CsPbBr3 point dosimeters, with linear dimensions meeting the strict spatial resolution constraints for bidimensional dose mapping required in clinical radiotherapy.