Design of a 32-channel high-performance OpenPET Detector Board

A successful OpenPET electronics system needs to provide electronics, especially front-end electronics that are powerful enough to accommodate cutting-edge research. While there are a tremendous number of variations, the relatively simple nature of the data ultimately collected implies that there can be a common set of requirements. In this paper, we describe a 32-channel high-performance Detector Board (DB) designed for OpenPET to meet those requirements. The input stage of the 32-channel DB accepts differential voltages between -2 V and +2 V and has input diodes to protect against over and under voltage. As the input is differential, detector signals of either polarity can be accommodated by selecting which inputs (positive or negative) they are connected to. The input signals are then split and feed to the high-performance energy circuits and the high-performance timing circuits. The outputs of the two circuits are feed to a FPGA for TDC calculation, event data generation and transmission. We have designed, fabricated and tested a 16-channel prototype DB. It functions as we expected. The 16-channel prototype DB has a similar schematic structure and the same digital parts (ADC, FPGA and etc.) as the 32-channel DB described in this paper. Based on the 16-channel DB, we have completed the schematic design and functional simulation of the 32-channel DB.