Authors:Pritty Rao, G. Reddy, S. Vikram Kumar, J. Ramana, N. Chattopadhyay, A. Basu, Seema Srivastava, R. Sarin, V. Raju, and Sanjiv Kumar
The paper describes the simultaneous determination of 14N and 15N isotopes in opium by proton induced γ-ray emission (PIGE) technique. The isotopic ratio of 14N and 15N is a useful parameter for assigning provenance of (seized) illicit drugs. The measurement, non-destructive in nature, is
performed on pellets made up of opium powders and is based on the prompt detection of 2.313 and 4.4 MeV γ-rays emanating from
14N(p,p′γ)14N and 15N(p,αγ)12C nuclear reactions respectively, induced simultaneously by 3.6–3.8 MeV proton beam. Positive as well as negative deviations
from the natural isotopic abundance (99.63:0.37) were observed in the samples. The precision of the measurements is about
4%. The methodology provides an easy and rapid approach to determine the isotopic ratio of 14N and 15N and has been used for the first time in the analysis of opium.
Authors:R.N. Acharya, K. Sudarshan, A.G.C. Nair, Y.M. Scindia, A. Goswami, A.V.R. Reddy, and S.B. Manohar
The guided thermal neutron beam at 100 MW Dhruva research reactor facility of Bhabha Atomic Research Centre (BARC) was used to carry out prompt gamma-ray neutron activation analysis (PGNAA). The prompt k0-factors have been determined for the isotopes of the elements H, B, K, Co, Cu, Ca, Ti, Cr, Cd, Ba, Hg and Gd with respect to 1951 keV gamma-line of 36Cl. The prompt k0-factors for H, Cl and Cu were also measured with respect to the 1381 keV gamma-line of 49Ti. Different samples like NH4Cl, Ti metal, cobalt chloride and other stoichiometric compounds and pure metals were used for this purpose. Prompt gamma-rays were accumulated using a 22% HPGe detector connected to a PC based 8k MCA in single mode counting. The energy calibration in the range of 100–8500 keV was carried out using gamma-rays from 152Eu and 60Co, and the prompt gamma-rays from 36Cl whereas the absolute detection efficiency for this energy range was determined using 152Eu and prompt gamma-rays from 36Cl and 49Ti.