Research on energy distribution of second electrons from photons impacting with atoms in tissue equivalent material

For research the energy distribution rules of second electrons from photons with different energy which impact with atoms in tissue equivalent material,based on theory analysis and some calculation,are drawed a conclusion that water is a sort of reasonable tissue equivalent material.The photon traces in the material were simulated by particle transport technique using Monte Carlo method.A large number photons were transported,the ratio of photoelectric effect to Compton effect was acquired in the tissue equivalent material,meanwhile the energy distribution states of second electrons were observed when photons impact with atoms(H、O) in the material.When the energy of photon is below 28keV,the probability of photoelectric effect will be significant;As the energy of photon is between 28keV～30keV,both photoelectric effect and Compton effect will happen in the same probability;The Compton effect will be mainly form in the material when the energy of photon is above 30keV.