Probing Gamma-Rays for Non-Destructive Detection of Hazardous Radioactive Nuclear Materials

. The shipment of nuclear materials is a matter of interest for both the public health and security. On the other hand, the smuggling of radioactive nuclear material is a source of concern for security agencies and the government. The current luggage scanning mechanism having limitations to detect nuclear materials and arrest the smuggling practices. Presently, material detection techniques are based on X-ray beams of a few hundred keV. However, neutron beams from particle accelerators are also the techniques to detect such materials. These require high cost for infrastructure, operations, and maintenance. In the present work, keep in mind low-cost and non-destructive methods to detect radioactive hazardous materials, a gamma-ray based method has been investigated for baggage scanning at airport or security check points. This method relies on the fact that whenever the gamma-ray of a certain energy is suppressed in the presence of another γ-ray of different energy. The low-energy gamma sits under the Compton region of nearby high energy gamma peak. In addition, low-energy gamma-ray intensity losses are sensitive to the atomic number of the absorbing medium, while that of higher-energy gamma-ray varies with the density. A combination of both low and high-energy gamma rays may be able to identify the radioactive material and its activity. In this work, an experiment was carried out at the Nuclear Security Education Laboratory, Amity Institute of Nuclear Science and Technology. To perform the experiment, a multi-energy gamma source spectrum is created with the combination of 60Co, 133Ba & 137Cs covering energies from 81.00 keV to 1332.50 keV. For the detection of gamma rays, a fast response scintillation detector i.e. 1.5 × 1.5 CeBr3 was employed. The gamma-ray spectrum was recorded using Genie software. The detector was associated with osprey-based electronics and connected to the computer. For the measurements, three radioactive materials were used as samples namely, 57Co, 54Mn and 22Na, of 44, 36 and 25 kBq, respectively. The observations were varied from 5 to 25 cm distances from the detector, subsequently, elongations in the peak heights have  obtained ranging from 3.26±0.02 to 423.01±2.47.