Energy loss straggling of heavy charged particles in thick silicon absorbers

The energy loss straggling of heavy charged particles with relatively high energies passing through thick uniform Si detectors (1.0 mm-9.2 mm) has been studied in a wide range of the ratio LI ΔE/E₀ where ΔE is the energy loss and E₀ is the initial energy of the incident particles. The experimental results are compared with those predicted by straggling theories. It suggests that the measured distributions are in good agreement with those predicted from the Bohr's or Livingston-Bethe's theories when ΔE/E₀<0.3 where the distributions are to be Gaussian-symmetric. However, the distributions for larger energy losses deviate from those expected from the theories. It is found that the experimental data are approximately expressed by the modified Stoquert's theory when the ratio ΔE/E₀>0.3.