We present a resonant Rydberg electric field s ensor o perating i n t he UHF band using a dual-optical-dual-microwave spectroscopy scheme. We measure Sirius XM satellite radio, and compare the sensitivity to other contemporary implementations of the technology.
We describe our progress toward a system to calibrate electrometers that measure currents from ionization chambers. The calibration system uses a 1 GΩ standard resistor in series with a stable voltage source to generate calibration currents from 1 pA to 20 nA, traceable to quantum voltage and resistance standards through an 8-1/2 digit digital multimeter and the standard resistor. Expanded uncertainties ( k=2) of 100×10 -6 or better for the calibration of the electrometer are needed for the ionization chamber measurements. We show our preliminary results including our initial calibration correction.
A novel four-terminal pair impedance bridge combined with a quantum Hall resistor will be presented. The impedance bridge is based on pulse-driven Josephson arrays. A very simple setup is possible due to the triple-series connection of the quantum Hall resistor that renders combining networks superfluous. This combination of the two well-known macroscopic quantum effects presents a unique possibility for the realization of electrical units. Moreover, the Josephson bridge can be used to precisely investigate the plateau shape of quantum Hall devices in the AC regime.
Magnetic flux leakage (MFL) testing is a commonly used technique for detecting and estimating the defect in ferromagnetic materials. The lift-off value has a great influence on the detected MFL signal which need more attention to study its impact. In this paper, the relationship between the MFL signal and the lift-off value has been analyzed based on the property of MFL signal. A simplified calculation model of MFL signal of defect has also been established here. To verify the proposed calculation model, a MFL testing of defect in a ferromagnetic pipeline has been conducted and the experiment result shows the well performance for the proposed model.
