Energy Absorbed in a Cell
Suppose N Joules of energy are deposited in a 70 kg human. Nominally the dose is N/70 Gy.
How much energy is deposited in a single (1µm)3 cell? (N/70)Gy * 10-15 kg= (N/70)*10-15 J= (1.3*10-17)*N J= [(1.3*10-17)*N]/1.609*10-19 J= 85*N eV. So itís a lot of energy!
Is the Bethe-Blocke continuous slowing-down approximation applicable here? No! Too much energy is being stopped per cell for it to be applicable. But we try to use it anyway.