To calculate the range of electron in matter, we will use CASINO 2.48 for its simplicity.
The name is from “monte CArlo SImulation of electroN trajectory in sOlids” , and was originated by Raynald Gauvin of Univ of Sherbrooke (Quebec). Download only the v2.48 version (Not the newer version v3.2 which is a 3d simulation which is a bit complicated.
Unzip the file . zip to a directory which contains the “int” folder at the same level as the .exe file. We can predict the range of electron from 11 keV to 100 MeV. We will calculate some path in air.
Au niveau de la mer, la masse volumique de l’air est de 0,001204 g/cm³. Cette densité diminue avec l’altitude, il faut prendre en compte cette variable dans les simulations.
Click on 1. « sample definition », then 2. « add layer » and double click on 3. « Undefined »
In Name type Air, then in Composition the O (for oxygen) and N ( for Nitrogen). Put the density and be sure that it apply it, because it’s a bit buggy at this point. Then you can modify the mix ratio of the composition. For air, it is about 22% of oxygen the rest if for Nitrogen (to simplify). Click done.
In the next icon, set 20 (for 20 keV, the initial energy of the electron). Then OK.
Then in the icon option, set minimum electron energy to 20 keV
Clik run
The trajectories appears. You can clik ton 1. to rescale, or to see the complete trajectorie, rescale the graph with 2.
So the range of a 20 keV electron in air is at most 6256136 nm or 6,25 mm.
With the Katz and Penfold formula, I obtain 5,55 mm.
A very nice program, like SRIM.