Kε AND TAN δ SPECTRA OF DRY LUNAR ANALOG MEASURED BY VARIOUS TECHNIQUES
For a two‐terminal measurement on a rock sample in a dry state whose dielectric loss tangent is less than unity, contact substitution without the insertion of any material between the electrode plates and the sample should be used to yield accurate measurements. The insertion may disturb measurements on the dielectric properties of the dry rock sample. A proposed optimum technique is useful when rock samples are not free of moisture and helps overcome electrode effects. Due to similarities in mineralogical composition and dielectric behavior, Duluth hornfels can serve as a terrestrial analog to some lunar basalts. The dielectric constant spectra of the Duluth hornfels measured during various stages in preparing a sample indicate that high dispersion at low frequencies is attributed mainly to the moisture content of the sample. Its intrinsic dielectric constant was found to be about 13, while its dielectric loss tangent linearly decreases from 0.07 at 100 hz to 0.019 at 100 khz in a log‐log plot. No Debye relaxation process was observed on the Duluth hornfels sample at room temperature over the frequency range used.