# Radiation - energy distribution of transmitted electrons

1. Dec 5, 2013

1. The problem statement, all variables and given/known data
What is the meaning of the peaks (for example between 100Kev and 400Kev) in a energy distribution of transmitted electrons graph where the y-axis is probability density (1/eV) and the x-axis is energy (eV) ?
When we simulate a source of photons with a given energy distribution against a phantom, which passes through a collimator.

3. The attempt at a solution
I know that the electrons appear due to Compton effect, for example, among other interactions. The probability density shows me the chance to appear with certain energy (which will be the peak), but what does the energy of the electron tells me? That radiation will penetrate more the phantom with higher energy electrons?