Tran, T., Chau, T., Hoang, T. and Vo, Y. 2011. STUDY ON THE EFFECT OF NATURAL BACKGROUND FOR GAMMA SPECTROMETER SYSTEM. Science and Technology Development Journal. 14, 4 (Dec. 2011), 16-23. DOI:https://doi.org/https://doi.org/10.32508/stdj.v14i4.2032.