A fishing lure device attracts fish using sound, movement, reflection and appearance. A miniature capacitor is constructed at the end of a coaxial transmission line which is immersed in the curing concrete so that the concrete is the dielectric of the capacitor, and step function voltage pulses are fed to the transmission line, while the reflected signal from the line is monitored. Pressing the button causes said dielectric test switch to stop the flow of electrical current from said electrically conductive strap to said earth leakage detection circuit to protect the circuit during dielectric testing. First and second traces are routed between the first and third contacts and between the second and fourth contacts, respectively, wherein the second trace is routed out of the die bonding area on a different layer than the first trace. For the model, geophysical tensor data is updated using a forward model at a plurality of locations using an interior method for constrained optimization. The accumulation of the ions in the potential well prior to generation of the pulse results in a thinner band of ions ejected into the drift chamber and hence achieves higher resolution.