Development of a Novel Proton Range Detector Using a Scintillator Disk Integrated With Copper Indium Gallium Selenide Solar Cells

Range errors in proton therapy can pose critical problems due to the steep dose gradient. Previously proposed range detectors using photomultiplier tubes and optical fibers have several limitations including use of external high-voltage sources, vulnerability to external forces, and complex signal transmission, which can cause inaccuracies in range measurement. This study aims to develop and assess a novel proton range detector that utilizes a scintillator disk with copper indium gallium selenide (CIGS) solar cells to overcome these challenges. The detector, consisting of a plastic scintillator disk, CIGS solar cells, and a data acquisition module, measures voltage signals from the solar cells through radioluminescence generated by the scintillator. We evaluated the dosimetric characteristics of our detector, focusing on range accuracy, dose linearity, dose rate dependence, energy dependence, spot position dependence. The detector showed range discrepancies of less than 1 mm, excellent dose linearity, dose rate independence within 1%, and energy independence within ±3%. Additionally, the signals near the disks center were consistent within 4% error across various spot positions. These findings suggest that the proposed detector, with its simplified configuration, offers high measurement accuracy and could be a promising alternative to other detectors based on photomultiplier tubes and optical fibers.