Simulation of nuclear quadrupole resonance for sensor probe optimization

A simulation method to estimate the detection efficiency of nuclear quadrupole resonance (NQR) was proposed for optimizing a sensing probe operating at radio frequencies (RFs). It first calculates the transmitted magnetic field from the probe coil to the target sample. The nuclei make quadrupole resonance by it. We considered this nonlinear reaction to estimate NQR emission by the nuclei. Then the received NQR signal intensity from the sample at the probe coil. We calculated the efficiency by testing two different probe types (solenoid and gradiometer) and by changing the relative positions of the probe and sample. The simulation results were in good agreement with the experimental results. [Display omitted] ► NQR-standoff detection has been investigated. ► Intensity of the detected NQR was calculated taking into account the total process. ► Nuclei dipole at the sample was nonlinearly induced by the RF radiation from a coil. ► The NQR signal emitted from the nuclei dipole was detected by the same coil. ► This simulation method was evaluated using a single and a gradiometer coil.