Low-Energy X-Ray Polarization Detector Detection Unit Prototype

The low-energy X-ray polarization detector (LPD) is a large-area and wide-field-of-view (FoV) X-ray polarimeter planned to be installed on the China Space Station. The LPD is designed to measure the polarization of gamma bursts and their early X-ray afterglows, facilitating studies of celestial bodies and radiation mechanisms at the centers of gamma bursts. The LPD consists of 15 detection units with identical structure and function. A detection unit prototype was developed, featuring six pixel detectors compactly placed on a bonding and front-end electronics (BFE) board with an effective detection area of $27.36~\rm cm^{2}$ . Each pixel detector has 16 analog output channels, after which data are amplified, digitized, and transmitted via the board-to-board (BTB) connector to the data acquisition (DAQ) board for processing. The prototype also includes an internal high-voltage circuit with up to −4-kV voltages. The test results indicate that the detection unit prototype can simultaneously read data from 96 channels of pixel detectors with an equivalent charge noise of 49.49 e $^{-}$ . It features comprehensive power management, offers configurable data compression, storage, and encoding, and meets all functional requirements of the detection unit.