1. Department of Physics, A.P.C. Roy Government College, Siliguri, Darjeeling 734010, West Bengal, India
2. Department of Physics, University of Burdwan, Golapbag, Burdwan 713104, West Bengal, India
3. Applied Nuclear Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India