Project Description

Research is underway to detect concealed explosives using quadrupole resonance (QR). QR systems detect threat quantities of explosives contained in sealed packages and are immune to false alarms caused by trace quantities. Unlike X-ray systems, QR systems are capable of detecting sheet explosives. The downside of this method is the low signal-to-noise ratio (SNR) of QR measurements that result in unacceptably large detection times. The SNR is limited in part by the Quality (Q) –factor of the QR probe. It is known that the SNR is proportional to the square root of the Q-factor. While normal metal coils have Q-factors on the order of 102, thin-film high-temperature superconductor (HTS) resonators have Q-factors on the order of 105 and therefore provide a significant enhancement in SNR. Unlike normal metal resonators, it was recently observed that the Q-factor of HTS resonators are dependent on the resonator current. The objective of this research is to generate a lumped parameter RLC model that describes the experimentally observed dependence of the Q-factor on resonator current.