Detection of explosives by nuclear quadrupole resonance

A system for detecting multiple types of nitrogen in a specimen by nuclear quadrupole resonance, comprising:

• pulse generating means for generating a plurality of trains of radio frequency pulses, each said train of radio frequency pulses having a distinct predetermined frequency;
• a plurality of meanderline surface coils for irradiating the specimen with each of said predetermined frequencies for said plurality of trains of radio frequency pulses and detecting a plurality of integrated nitrogen signals in response to irradiating the specimen with each of said distinct predetermined frequencies;
• a plurality of coupling means for respectively transmitting each of said plurality of said trains of radio frequency pulses to each of said meanderline surface coils and respectively receiving said integrated nitrogen signals from each of said meanderline surface coils;
• comparing means for comparing each of said integrated nitrogen signals to a predetermined threshold value;
• and
• an alarm for signalling when each of said integrated nitrogen signals exceeds said predetermined threshold value.

A system for detecting multiple types of explosives and narcotics containing nitrogen in a specimen by nuclear quadrupole resonance, comprising:

• pulse generating means for generating a plurality of trains of radio frequency pulses, each said train of radio frequency pulses having a distinct predetermined frequency;
• a meanderline surface coil for sequentially irradiating the specimen with each of said distinct predetermined frequencies for said plurality of trains of radio frequency pulses and detecting a plurality of integrated nitrogen signals in response to sequentially irradiating the specimen with each of said distinct predetermined frequencies;
• coupling means for sequentially transmitting each of said trains of radio frequency pulses to said meanderline surface coil and sequentially receiving said integrated nitrogen signals from said meanderline surface coil;
• comparing means for comparing each of said integrated nitrogen signals to a predetermined threshold value;
• and
• an alarm for signalling when each of said integrated nitrogen signals exceeds said predetermined threshold value.

A system for detecting a class of explosives and narcotics containing nitrogen in a specimen by nuclear quadrupole resonance, comprising:

• pulse generating means for generating a train of radio frequency pulses having a predetermined frequency;
• a meanderline coil for irradiating the specimen with said train of radio frequency pulses and detecting an integrated nitrogen signal in response to irradiating the specimen;
• coupling means for transmitting said train of radio frequency pulses to said coil and receiving said integrated nitrogen signal from said coil;
• comparing means for comparing said integrated nitrogen signal to a predetermined threshold value;
• and
• an alarm for signalling when said integrated nitrogen signal exceeds said predetermined threshold value.

A method for detecting a class of explosives and narcotics containing nitrogen in a specimen by nuclear quadrupole resonance, comprising the steps of:

• (a) generating a train of radio frequency pulses having a predetermined frequency;
• (b) transmitting said train of radio frequency pulses to a meanderline surface coil;
• (c) irradiating the specimen in response to said train of radio frequency pulses transmitted to said meanderline surface coil at said step (b);
• (d) detecting an integrated nitrogen signal in response to irradiating the specimen at said step (c);
• (e) receiving said integrated nitrogen signal detected at said step (d);
• (f) comparing said integrated nitrogen signal to a predetermined threshold value;
• and
• (g) signalling when said integrated nitrogen signal exceeds said predetermined threshold value.