ionization region
1.The Hatree Fock relativistic(HFR) method has been used to calculate the cross section of photoionization and the Bethe coefficient of all charge states of Al. The latter, which dominates the cross section of electron impact ionization at high energy region, is also related to the cross section of photoionization.
2.Methods Using the PTW Marcus 23343 type fixed-separation parallel-plate ionization chamber in a special ph an tom(PMMA), the change of photon dose buildup region was measured with rectificat ion of Bruce empirical formula.
