Penetrating Power (1 Viewer)

[skinnier]

i know that this isnt directly in the course but i was wondering what affects penetrating power

 

[independantz]

ionisation energy? not entirely sure

 

[kony]

basically how easily the particle can get through the matter.

if it has charges, then electrostatic forces between the particle and nuclei will slow it down, reducing its energy and hence it won't penetrate as far. this is why neutrons are much better at penetration than say, protons.

also, it depends on the size of the particle. the bigger it is, the more likely it is to collide with something along its path, hence slowing it down, etc. this is why beta particles have higher penetrating power than alpha particles. it is much smaller.

combined, gamma rays have 1) no charge 2) no mass.

therefore, it can never truly be stopped, only some of its energy absorbed.

 

[jlnWind]

basically how easily the particle can get through the matter.

if it has charges, then electrostatic forces between the particle and nuclei will slow it down, reducing its energy and hence it won't penetrate as far. this is why neutrons are much better at penetration than say, protons.

also, it depends on the size of the particle. the bigger it is, the more likely it is to collide with something along its path, hence slowing it down, etc. this is why beta particles have higher penetrating power than alpha particles. it is much smaller.

combined, gamma rays have 1) no charge 2) no mass.

therefore, it can never truly be stopped, only some of its energy absorbed.

Sorry i think this is incorrect. Because as far as I've heard neutrons are a better probe than x-rays and x-rays have no charge/ no mass. But neutrons are more penetrative than they are?

Gamma rays, and x-rays, and all EMR, can be stopped. If you have a closed box and put a torch inside and turn it on, do you see any light? If all the photons collide they (as Einstein put in photoelectric effect) transfer all their energy to the atom (all or nothing principle).

Penetrative power does depend on charge and mass. I think the most important factor however is charge. Electromagnetic energy interact with the electrons in the electron cloud. However neutrons (which are massive) do not interact with any of them because it is not effect electrostatically. It reacts mainly with nuclei, and even then only because the protons and neutrons are massive (not because of their charge).