phan-loai-tia-phong-xa
buc-xa-alpha-α
buc-xa-beta-β
buc-xa-gamma-γ
phan-tich-cac-nguon-phat-sinh-ra-tia-phong-xa
nha-may-dien-hat-nhan
hau-qua-cua-viec-nhiem-phong-xa