Damar Adhiwidya Suyanto et al. 2025. The Simulation of Radiation Shielding Made of Portland Material in a 230 MeV 300 NA Cyclotron Room for Proton Therapy Facility Using PHITS Code System. Jurnal Engine: Energi, Manufaktur, dan Material. 9, 2 (Nov. 2025), 237–248. DOI:https://doi.org/10.30588/jeemm.v9i2.2339.