Design and characterization of thin-film sensor and RADFET modules for radiation monitoring on the BIRDSRPM satellite
Technical Insights & Hardware Design
The development of the Sensor and RADFET modules represents a collaborative aerospace initiative tailored for the BIRDS-RPM satellite platform.
The Sensor Module
The core engineering challenge addressed within the Sensor module was the implementation of ultra-low current acquisition topologies. Because the integrated four thin-film sensors exhibit extremely high electrical resistance—ranging from 100 kΩ up to 10 MΩ—any leakage current or trace impedance on the PCB could severely compromise data integrity. The instrumentation front-end was optimized to isolate and safely sample these minor current fluctuations under simulated and direct cosmic radiation fields.
The RADFET Module
To establish a reliable analytical baseline, the secondary RADFET module operates in tandem using dual-topology radiation mapping:
- Real-Time Dose Rate: Monitored via a high-precision PIN diode, capable of capturing rapid dose rate transitions from 0.1 µSv/h to 100 mSv/h.
- Total Ionizing Dose (TID): Measured using a dedicated RADFET (Radiation-Sensing Field-Effect Transistor) configuration, logging cumulative spatial exposure across a wide dynamic range from 1 cGy to 1 kGy.
Low-Power Architecture & In-Orbit Logging
Both modules utilize the I²C (Inter-Integrated Circuit) communication protocol as their primary data bus link to the satellite’s Central Data Handling unit. This interface permits seamless telemetry logging, enabling the system to pack, buffer, and queue sensor diagnostics for subsequent downlinks to Earth ground stations. The design strictly prioritizes low-power constraints, spatial volume minimization, and hardware fault tolerance necessary for prolonged orbital operation.