Electret Based Wireless Micro Ionizing Radiation Dosimeter

Wireless ionizing radiation sensors have a wide range of applications in areas such as radiation therapy, environmental monitoring, and homeland security. It is preferable to manufacture such sensors using passive elements since ionizing radiation can damage active electronic components. This paper reports the development of a first micromachined totally passive electret based wireless ionizing radiation dosimeter for high dose radiation therapy applications. Wireless Ionizing radiation measurement is performed by monitoring the resonance frequency change with a phase-dip technique. Device test results show that 60,000R gamma-ray ionizing radiation exposure produces a 687kHz resonance frequency shift resulting in a sensitivity of 11.45kHz/kR.