Speaker
Description
For low-energy rare-isotope beam experiments, a 5 x 5 cm$^2$ quadrant silicon pad sensor was developed for the TexAT active target system. To prevent premature breakdown in large-area segmented sensors, three guard-ring configurations (G6, G9, G14) were investigated via TCAD simulations and experimental measurements. Simulations proved that the G9 design, using a graded-spacing strategy, mitigates electric-field concentration more effectively than the 14-ring design. The fabricated G9 sensor demonstrated a low leakage current of several tens of nA and an energy resolution of approximately 31 keV (FWHM) for 3.18 MeV $\alpha$-particles from $^{148}$Gd. In-beam tests at RAON verified its operational reliability, providing key design criteria for TexAT detectors.