A Josephson effect apparatus for the undergraduate laboratory

Abstract

An apparatus to enable the observation of the Josephson effect is described. Simplifications in the construction make it suitable for use as an undergraduate laboratory experiment. The superconducting tunnel junction is formed after cooling to liquid helium temperature in an ordinary storage dewar. The conductors of a coaxial waveguide serve to draw together the two elements of the junction, which is then irradiated with X-band microwaves transmitted by the guide. Accurate determination of the microwave frequency and the voltage interval between the current steps lead to a value of e/h.

Anisotropy of wood in the microwave region

“…Usually, microwaves are discussed during undergraduate courses. The interference and diffraction [4], Bragg reflection, evanescent absorption [5] and other phenomena [6,7] are discussed during lectures or studied in the laboratory. In spite of an intensive literature search, we were able to find only one study of the anisotropic properties of wood for educational purposes [2].…”