Tracking electric field exposure levels through radio frequency dosimetry

The radio-frequency (RF) dosimeter developed by the Oak Ridge National Laboratory is a portable, pocket-sized cumulative-dose recording device designed to detect and record the strengths and durations of electric fields present in the work areas of naval vessels. The device measures an integrated dose and records the electric fields that exceed the permissible levels set by the American National Standards Institute. The features of the RF dosimeter are described. Data obtained with the RF dosimeter will be used to determine the ambient field-strength profile for shipboard personnel over an extended time. Readings are acquired and averaged over a 6-min period corresponding to the rise time of the core body temperature. These values are stored for up to six months. The proposed specifications for the RF dosimeter included a sensitivity range of 1 to 1000 mW/cm² , an audible alarm for fields >8 mW/cm,², integration of dosage for later readout, autoranging capability, and a possible self-powering capability. The design process, starting with the sensor, is detailed, and the tests completed on the final product are described