The wide application of the modern resonant measurement techniques makes all the steps of the measuring process, including data acquisition more efficient and reliable. Here we investigate the multidimensional space of the parameters to determine the optimum span for resonant measurements. The study concentrated on experimental systems with standard performance and capabilities. We determine the range of the optimum span for the resonant frequency and quality factor by simulating and fitting resonant curves with different levels of asymmetry.
For one PCB trace region, where bare high voltage trace goes near GND pad, we estimated an electrical breakdown voltage in low vacuum using simplified geometrical model under some assumptions. Experimental measurement of Paschen curve for the PCB board considered was proceed in pressure range from 2x10-3 mbar to 25 mbar.
The microwave resonator is one of the key components in the modern Electron Paramagnetic Resonance (EPR) spectroscopy setup, as it largely determines the performance characteristics and limitations of the entire spectrometer. In this research note the possible way of resonator optimization is described. A detailed computer model describing the distribution of the electromagnetic field for Bruker 4118X-MD-5W1 design resonator has been developed. All details including a dielectric insert, conductive screen, coupling antenna and PTFE supports were included in the model. All dissipation processes were considered in the calculation. The influence of the resonator geometry on the Q-factor, filling factor and operating frequency of the resonant mode has been investigated. The resonator geometric parameters are optimized to achieve maximum sensitivity. According to the calculations, the optimized resonator structure has in 10 times greater sensitivity than the original MD-5 design.
Sensitive, real-time optical magnetometry with nitrogen-vacancy centers in diamond relies on accurate imaging of small ($ll 10^{-2}$) fractional fluorescence changes across the diamond sample. We discuss the limitations on magnetic-field sensitivity resulting from the limited number of photoelectrons that a camera can record in a given time. Several types of camera sensors are analyzed and the smallest measurable magnetic-field change is estimated for each type. We show that most common sensors are of a limited use in such applications, while certain highly specific cameras allow to achieve nanotesla-level sensitivity in $1$~s of a combined exposure. Finally, we demonstrate the results obtained with a lock-in camera that pave the way for real-time, wide-field magnetometry at the nanotesla level and with micrometer resolution.
This note presents a method to tune the resonant frequency $f_{0}$ of a rectangular microwave cavity. This is achieved using a liquid metal, GaInSn, to decrease the volume of the cavity. It is possible to shift $f_{0}$ by filling the cavity with this alloy, in order to reduce the relative distance between the internal walls. The resulting modes have resonant frequencies in the range $7div8,$GHz. The capability of the system of producing an Electron Paramagnetic Resonance (EPR) measurement has been tested by placing a 1 mm diameter Yttrium Iron Garnet (YIG) sphere inside the cavity, and producing a strong coupling between the cavity resonance and Kittel mode. This work shows the possibility to tune a resonant system in the GHz range, which can be useful for several applications.
We survey techniques for constrained curve fitting, based upon Bayesian statistics, that offer significant advantages over conventional techniques used by lattice field theorists.