Abstract: A low-energy ion spectrometer has been successfully developed, with the objective of measuring low-energy ions of 100 eV/e ~25 keV/e on a three-axis stabilized satellite in geosynchronous orbit. This instrument requires that the readout electronics system has the characteristics of 16 micro-channel plates (MCP) channels for 22.5° angle resolution detection, sensitivity higher than 1 × 104 electrons, event rate up to 10 MHz, and less than 10 W power consumption.
In this paper, radiation-hardened readout electronics has been designed for the detector, considering the space radiation environment. The system consists 16 low-noise charge sensitive preamplifier-discriminators (A121s) which are employed for data acquisition of MCP channels to use in fast pulse counting mode, antifuse field programmable gate array (FPGA) which is used for data storage and package, high voltage (HV) control, self-test circuits, states monitor module and communication module with upper host. In addition, what improve the reliability of the system is the FPGA-based satellite onboard software adopts the method of triple modular redundancy (TMR) and refreshes all external key registers at regular time.
During the performance experiments, the test results show that the readout electronics achieves 12 MHz event rate, 5 × 104 electrons sensitivity, and total power consumption of 4.73 W, showing that the performance meets the spectrometer physical requirement. The system stably operates all function in a series of environment tests.
Key words: Low-energy ion spectrometer, Readout electronics, Antifuse FPGA, A121