New Instrumentation for High-Power Pulsed Microwave Biological Effects Research

Research is beginning to be performed to assess the biological effects of radiation that is emitted from a new generation of extremely high power, short-pulse microwave generators. These generators produce hundreds or thousands of Megawatts of peak power with sub-microsecond pulse durations. Studies of the basic mechanisms of interaction of this form of RF radiation need to be performed on biological systems and biomaterials to establish a basis for the establishment of personnel safety standards. New measurement tools are required to enable the quantification of the dose-response relationship for high power microwave exposures of experimental biological specimens. Specifically, the internal electric field strength, rate of temperature rise, and acoustic pressure must be measured. In addition, the dielectric properties of biological tissues that are exposed to very brief, intense E fields must be determined. New devices and measurement techniques must be developed or adapted from the EMP and nuclear Instrumentation communities in order to provide the means for determining these dosimetric parameters. Electro-optic devices and fiber optics can be employed for measurements within biological systems. Optical technology enables sensors to be produced with instantaneous bandwidths of thousands of MHz while eliminating undesirable metallic leads. The new measurement techniques mentioned above differ appreciably from the traditional dosimetric techniques that have become well established for research on CW microwave biological effects. A discussion of these new devices is presented.