Femtosecond laser-based TCT-TPA and IBIC microscopy: two powerful depth profiling characterization tools for testing the micron-sized sensitive volumes in micro-strips or pixeled detectors for microdosimetry and hadron therapy

Advanced radiation therapy requires advanced instrumentation for dose delivery and beam monitoring. On the other side, research and development of state-of-the-art radiation detectors require research and the development of advanced techniques and instrumentation for characterizing these detectors. The newly developed timing sensors with good spatial and timing resolution, such as low gain avalanche diodes, become very attractive devices to be exploited and integrated in an innovative way into pCT, PET systems, or some other hybrid technologies for microdosimetry. For this purpose, a high fill factor (the ratio of the active area and the total sensor area) and excellent isolation of pixels must be achieved. In the scope of study of the region between the two pixels, the two characterization techniques are presented in this paper: ion beam induced charge (IBIC) and two-photon absorption-transient current technique (TPA-TCT). The accuracy of methods and the precision of the measurements of the interpad distance (IP) are investigated by comparing the experimental data to the nominal values provided by vendors of the prototypes.

Automated summary

Advanced radiation therapy requires advanced instrumentation for dose delivery and beam monitoring. Research and development of state-of-the-art radiation detectors is necessary for the characterization of these detectors. The newly developed timing sensors with good spatial and timing resolution can be integrated into innovative technologies for microdosimetry. Two characterization techniques, ion beam induced charge (IBIC) and two-photon absorption-transient current technique (TPA-TCT), are presented in this paper for studying the region between two pixels.