This study presents a novel embedded FPGA design utilizing Time-over-Threshold (ToT) and Double-Time-over-Threshold (DToT) methods, addressing the limitations of traditional analog-to-digital converters (ADCs). The ToT method has gained popularity due to its advantages in power consumption, cost, and integration, yet it faces challenges such as energy vs. time resolution trade-offs and signal nonlinearity. The proposed DToT method aims to mitigate these issues by employing two thresholds, offering improved energy resolution and reduced nonlinearity compared to single-threshold ToT methods. The system is implemented on a Zynq System-on-Chip (SoC) that integrates an FPGA with an ARM CPU, enabling dynamically adjustable thresholds, high-precision timing measurements, and flexible data processing capabilities. The evaluation was conducted using a CAEN DT4800 Digital Detector Emulator, which generated signals from a 3-inch NaI detector exposed to a 22Na radioactive source. The results demonstrate the superior precision of the DToT method, particularly at lower energies, with σ/μ ratios of 1.82% and 3.82% for the 511 keV and 1275 keV peaks, respectively. This FPGA-based approach provides a versatile and high-precision solution for instrumentation applications, offering significant advantages over traditional ADCs and single-threshold ToT methods. The integration of an ARM CPU with FPGA logic allows for flexible and tunable signal processing, making it suitable for a wide range of applications, including particle physics experiments, medical imaging systems, and industrial sensors. The study underscores the potential of DToT for high-resolution spectroscopy and suggests areas for future research, such as optimizing the system for specific experimental setups in scintillation gamma cameras or positron emission tomography (PET).
Aydın Tarık Zengin (Wed,) studied this question.