Suyanto, D.A. et al. 2025. Shielding innovation for health security: A PHITS-based optimization of Portland material for proton therapy. International Journal of Applied Mathematics, Sciences, and Technology for National Defense. 3, 2 (Aug. 2025), 103–116. DOI:https://doi.org/10.58524/app.sci.def.v3i2.841.