NQR Detection of Ammonium Nitrate in Partially Shielded Volumes

In this work, we describe the experiments for the detection of ammonium nitrate (AN) with a toroidal RF probe with an effective detection volume of 137.5 L. The system includes a Tecmag Scout NQR console, a Tomco linear power amplifier (4 kW), a duplexer and a high-power Q-factor spoiler. We studied the influence of partial metal shielding with an aluminium foil as well as the inclusion of metal pieces in an AN sample on the detection of the AN NQR signal. We have also tested NQR detection of AN placed in the open box made of soft iron plates. We have shown that the detection of the NQR signal of AN in the configurations where there is a hole in the shield around the AN sample is possible.