METHOD OF IDENTIFYING CONCEALED EXPLOSIVES AND NARCOTIC DRUGS Russian patent published in 2012 - IPC G01N23/222 

FIELD: physics.

SUBSTANCE: analysed substance containing nitrogen and/or carbon is irradiated with a pulse of gamma-radiation. Secondary radiation from decay products formed by nitrogen-12 and boron-12 isotopes is picked up. The time spectrum of secondary radiation signals is recorded. The abundance ratio of nitrogen and carbon is determined from the obtained time spectrum analysis results. The analysed substance is identified based on its carbon and nitrogen composition through comparison with standard values from a data base. The time spectrum of the secondary radiation is recorded in a limited time interval, which starts from the end of the radiation pulse with time delay. The spectrum is processed by converting the measured differential time spectrum into an integral time spectrum. Determination of the abundance ratio of nitrogen and/or carbon in the sample is carried out for several time intervals of the measured spectrum. Accuracy of detecting substances containing nitrogen or carbon is determined by comparing values of abundance ratio of nitrogen and oxygen in the sample, calculated for different time intervals.

EFFECT: high accuracy and reliability of a photonuclear detector of explosive and narcotic substances with simultaneous increase in efficiency thereof.

3 cl, 3 dwg