Transimpedance amplifiers for large-area and ultrahigh bandwidth high-energy particle detectors

In the realm of high-energy particle detection, a trade-off exists between achieving a large sensitive area and ensuring high-speed detector response. Current methodologies, such as negative Miller capacitance, have made progress in enhancing both detection area and response speed. Nevertheless, these designs frequently suffer from limitations in parasitic capacitance, especially with large detection areas, which ultimately constrains bandwidth. This study introduces a segmented-integration method combined with optimized front-end circuits to overcome these challenges. By segmenting a single large sensitive area into smaller pixels, each coupled with an independent front-end transimpedance amplifier (TIA), this design can significantly enhance the response speed while maintaining a large sensitive area. Although it complicates the overall system, the output signals from each pixel are summed to preserve the detector's large-area capability. This study has developed novel front-end circuits for both linear and Geiger modes, offering exceptional performance in terms of detector gain and bandwidth. In linear mode, a multi-channel TIA is designed to handle up to 32 pixels simultaneously, providing a gain of 50 dBΩ and 450 MHz bandwidth despite 160 pF parasitic capacitance. For Geiger mode, a novel TIA with a feedforward is proposed, providing a gain of 70 dBΩ and 450 MHz bandwidth for a pixel with a 5 pF parasitic capacitance without the need for compensating capacitors. To enable rapid single-particle counting, a four-delay trigger sampling comparator structure is designed with a sampling rate reaching 4 GS/s under process limitation. The circuits are designed in 180 nm CMOS process and verified through Sentaurus and Cadence simulation software, demonstrating excellent performance with a 68.8 mm² detection area and an ultrahigh cutoff frequency of 450 MHz.