The energy loss of protons or silicon nuclei due to nuclear scattering is calculated using binary collision approximation and the " magic " formula is used to calculate the scattering angle . the electronic energy loss is calculated by bethe - bloch formulation at high energy , by linhard - scharff formulation at low energy and the interpolation formulation is used for the medium energy region . the nuclear reaction is calculated using intra - nuclear cascade model 核散射采用經典兩體碰撞近似,并用“夢幻”公式求解散射角;電子阻止在高能時采用bethe - bloch公式,低能時采用lindhard - scharff公式,中能時采用biersack的插值公式;核反應過程采用核內級聯模型。