A Low-Power LGAD–Timepix Dosimeter for Biological Space Radiation Monitoring

In the long-term objective of extending human presence beyond Earth’s orbit, gaining a deeper understanding of how the space environment affects biological systems has become a critical challenge. Prolonged exposure to space radiation, microgravity, and isolation poses serious health risks, including degenerative pathologies that may compromise the safety and performance of astronauts during deep-space missions. ALCYONE, an EU-funded project under the Horizon Europe program, is directly driven by the need to investigate these risks and develop miniaturized, automated systems capable of monitoring biological responses in real space conditions.<br/>Building on the heritage of previous missions such as AstroBio CubeSat and inspired by the compact, lowpower, and modular design of CubeSats, ALCYONE introduces a novel platform that integrates microfluidic cell culture technology with advanced radiation sensing. The project features a miniaturized on-chip microincubator with embedded thin-film sensors and actuators to precisely control and monitor the cellular environment for four different types of cell cultures. A critical innovation in ALCYONE, along other technological<br/>development regarding the miniaturized lab-on-chip system, is the development of a next-generation, ultralow power dosimeter system, designed specifically for long-duration biological experiments in space.<br/>The dosimeter is based on Timepix front-end chips, a technology that has already demonstrated its robustness and effectiveness in several space missions. In ALCYONE, this proven technology is further enhanced by the integration of newly developed trench-isolated, fine-pitch low-gain avalanche detectors (TI-LGADs), fabricated by FBK. These novel pixelated sensors are bump-bonded to the Timepix readout chips, resulting in a new class of hybrid detectors that combine high spatial and temporal resolution with enhanced sensitivity.<br/>One of the key innovations introduced by the LGAD-based sensors is the gain layer, which amplifies the collected charge at the pixel level. This additional signal gain can be exploited to reduce the power consumption of the analog front-end circuitry of the Timepix chip, enabling longer mission durations and more efficient data collection under tight energy constraints typical of CubeSat platforms. Moreover, a secondary benefit of the gain layer is its ability to enhance photon detection, which opens new possibilities for dual-functionality<br/>in the same pixel matrix.<br/>Specifically, the same sensor array can be reconfigured to operate as a high-speed, fine-pitch optical camera. This feature is particularly relevant for observing fluorescence emitted by bacterial cultures in response to radiation exposure. Since the intensity and photon yield of this fluorescence is typically low, the increased sensitivity, provided by the gain layer, is essential for accurate and meaningful detection. This dual-use capability of the detector combining precise dosimetry and sensitive bio-imaging positions ALCYONE as a transformative tool for space biology.<br/>In conclusion, ALCYONE delivers a fully integrated and miniaturized instrumentation platform, combining advanced radiation detection and microfluidic bio-laboratory functionality. It addresses a major technological<br/>gap in space biology research by providing a new class of bio-detectors not currently available on the market, with potential applications not only in space missions but also in terrestrial biomedical research and diagnostics.