PNNL

Abstract

Millimeter waves (30 – 300 GHz) are ideally suited for sensing and diagnosing materials, devices, and processes that are broadly important to energy, environment, and national security missions. The wavelengths are long enough to penetrate dust, smoke, and industrial environment yet short enough to enable focusing and manipulating of the signals for useful applications. We have developed a novel thermal return reflection (TRR) technique that uses emission as a probe to interrogate and diagnose materials and systems and determine emissivity and temperature simultaneously. Scientific basis of TRR, 2-D and potentially 3-D measurements, and selected results on application of TRR will be presented. We will also present new sensor concepts based on emit-probe and pump-probe modes to further broaden its applications. In its 3-D manifestation of this technique, one can track three different parameters or view/measure at three different directions (x, y, and z). On application to materials and processes, it shows promise for measuring temperature (T) - position (x) - time (t) simultaneously in real time leading to T-x-t diagrams that can be exploited for spatial resolution of emissivity or stability over a function of time. Selected examples of applications in fusion plasma diagnostics, nuclear waste disposal, and non-proliferation will be presented.