Mohammed L, Hussain A. Universal empirical relationship between efficiency of scintillation detector NaI(Tl) with gamma ray energy and distance using gamma spectroscopy (UCS-20). EDUSJ [Internet]. 2008 Sep. 1 [cited 2025 Aug. 6];21(3):138-52. Available from: https://ojs.uomosul.edu.iq/index.php/edusj/article/view/23526