Wearable, wireless sensor platform for occupational radiation dosimetry applications

Presented is a low-power wireless ionizing radiation monitoring circuit intended to be worn for occupational dosimetry. The sensor element is a custom MOS capacitor which traps holes in proportion to the amount of ionizing radiation detected, thus permanently causing a lateral shift in the CV-curve (toward more negative threshold voltage). The circuit measures the capacitance value of several redundant sensors at a given voltage in the depletion region, records this value over time and occasionally transmits the stored values to a base station. The 32 mm × 46 mm circuit utilizes a Nordic nRF51422 system-on-chip with a S310 SoftDevice to form a Bluetooth connection. From the change in capacitance, the dose that has been delivered can be determined. Measurement resolution is approximately 0.1 mSv (10 mRem), making this a viable technology for occupational dosimetry.