Radio frequency illumination based temperature modulated-nuclear quadrupole resonance and signature detection of potential threat

A method for detecting presence of substances, comprising:

• illuminating a target-of-interest (TI) with an RF energy configured to effect, over a time duration extending from a first time to a second time that is subsequent the first time, an increase in a temperature of the TI;
• measuring at a time corresponding to the first time, a first temperature NQR signal spectrum of the TI, and outputting a corresponding first NQR spectrum data set;
• measuring at a time corresponding to the second time, a second temperature NQR signal spectrum of the TI, and outputting a corresponding second NQR spectrum data set;
• and
• classifying, based at least in part on the first NQR spectral dataset and the second NQR spectral dataset, the TI between including the SI and not including the SI.

A method for detecting presence of substances, comprising:

• effecting a temperature increase in a target-of-interest (TI), within a detection space, by operations including illuminating the TI with an RF energy configured for absorption by the TI;
• establishing in the detection space, while illuminating the TI with the RF energy configured for absorption by the TI, a pulsed HF excitation field configured to excite NQR resonance of a substance of interest (SI);
• receiving signal radiations from a direction of the detection space, over a plurality of time intervals that follow pulses of the pulsed HF excitation field, during the illuminating the TI, and outputting a corresponding plurality of NQR spectral datasets;
• and:
• classifying, based at least in part on the plurality of NQR spectral datasets, the TI between including the SI and not including the SI.