X-/γ-Ray Detection Instrument for the HERMES Nano-Satellites Based on SDDs Read-Out by the LYRA Mixed-Signal ASIC Chipset

This paper presents the front-end section of the X-/γ-ray detection instrument of the HERMES mission, whose goal is to observe and localize γ-ray bursts, through a constellation of more than one hundred nano-satellites. Considering the severe volume and power consumption constraints of the nano-satellites, in the HERMES X-/γ-ray detection instrument, silicon drift detectors are read out through a mixed-signal ASIC chipset, called LYRA, based on a peculiar architecture. In particular, a small front-end ASIC (LYRA-FE), placed close to each silicon drift detector, is connected, through a current-mode link, to a multi-channel back-end ASIC (LYRA-BE). The LYRA ASIC chipset, implemented in a 0.35µm CMOS technology, achieves less than 22e−rms of equivalent noise charge, with a power consumption lower than 600µW/channel from a 3.3V power supply. Thanks to the current-mode link between the LYRA-FE and the LYRA-BE ASICs, no significant crosstalk among channels can be observed, in spite of the length of the interconnection wires as large as 12cm.