S. Liura 1. Department of Physics, Faculty of Mathematics and Natural Sciences, University of Indonesia, Jl. Margonda Raya, Depok 16424, Indonesia
2. Department of Radiotherapy, MRCCC Siloam Hospitals, Jl. Garnisun No.5, Semanggi, Jakarta 12930, Indonesia Indonesia
S.A. Pawiro Department of Physics, Faculty of Mathematics and Natural Sciences, University of Indonesia, Jl. Margonda Raya, Depok 16424, Indonesia Indonesia