Main Question or Discussion Point
what makes an alpha particle more strongly ionising than an electron? It is simply because of the fact that the alpha particle has a greater (double the) magnitude of charge?
It has to do with relativistc effects, and more. But the relativistical effects and that the most promiment scatterer in a material are the atomic electrons - which has the same mass as the incoming electron. And here you can just play with your newtonian mechanics - linear momentum. Check that an object of mass 8000e , with momentum p, impinging on an obejct of mass 1e - will loose much less energy than a object of mass 1e and momentum p, impinging on an object of mass 1e will do. That was a classical analogy.yeah I understand it arises from the Bethe-Bloch equation (well specifically, the equation for "range", which does show a mass dependence).
What is I am unclear about is the physical basis for why it is so? That is, why would an electron of the same momentum as an alpha particle be less ionising?
First, are you with me on the classical analogy?thanks glenn.
"check that an object of mass 8000e , with momentum p, impinging on an obejct of mass 1e - will loose much less energy than a object of mass 1e and momentum p, impinging on an object of mass 1e will do. That was a classical analogy."
does that not depend on how much momentum is *transferred* to the gas atoms (by the charged particle). Why would a lighter particle neccessarily *transfer* more momentum than a heavier one?