Primary ionization and energy loss calculation for helium, neon, argon and krypton

We performed a calculation of the energy loss dE/dx and the primary ionization density dN/dx for a charged heavy particle crossing a gas volume as a function of the particle β. We start from the Maxwell equation and using the experimental values of the photo-absorption cross section, we take into account the different material properties. Our calculation of dE/dx is in excellent agreement with the Bethe–Bloch function and in the case of dN/dx we found a relativistic rise and a good agreement with the primary ionization experimental data we compare. We consider the possibility to use primary ionization measure to make the particle identification in the large tracking chambers.