Design and Verification of Multi-Channel PP-MVT Digitizers for Enhanced Photodetection

Photodetection systems rely on precise pulse sampling to achieve accurate detection, which is crucial for highprecision applications such as positron emission tomography (PET) and LiDAR. To improve pulse sampling accuracy, the peak-picking multi-voltage threshold (PP-MVT) method incorporates peak information into the conventional MVT method, thereby enhancing pulse recovery accuracy and energy resolution (ER). However, for multi-channel PP-MVT digitizers, traditional analog to digital converters (ADCs) either increase the cost per channel or limit the counting rate, which restricts the scalability and deployment. To address this critical technical challenge, we design and verify a multi-channel PP-MVT digitizer which digitizes solely through time-to-digital converters (TDCs) with minimal extra hardware usage of only 6 IO per channel. To demonstrate the feasibility, we implemented a single-channel prototype, achieving peak picking accuracy with a RMSE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</inf>of 4.79 ns and a RMSE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</inf>of 22.20 mV. Additionally, using an LYSO/SiPM photon detector under the radiation of a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sup>Na source, the PP-MVT digitizer demonstrated superior and more stable sampling performance compared to the conventional MVT method. This work establishes a foundation for scalable multi-channel PP-MVT digitizers, demonstrating potential for highdemand photo detection systems.