How does the density effect correction affect dE/dx in the Bethe-Bloch Equation?

[PatrickRowe]

Hello all, I'm currently doing something that isn't technically coursework but I felt that this was the best place for my question, as an investigation into the properties of particles moving through matter, i have been trying to evaluate dE/dx in the Bethe-Bloch Equation:

http://pdg.lbl.gov/2005/reviews/passagerpp.pdf

However, my data isn't coming out as i would have hoped, these graphs show an increase in dE/dx as \beta\gamma approaches 1000, i see a steady decrease.

I have been excluding the density effect correction from my calculations because I assumed it was applicable only to energies above those where i am operating. I have found the descriptions available online hard to understand, however, as i can't see how they vary at all with velocity or any other variable. I'd be very grateful if someone was able to give a simplistic description of this to get me on my feet! Thank you all in advance.

Ps, If you would like to see the excel file I'm using i'll happily create an external link to it.

 

[member 553083]

The density effect correction term in the Bethe-Bloch equation is a correction factor that takes into account the fact that at higher energies, particles interact more with the medium they are traveling through, thus losing more energy (and hence having a larger dE/dx). This is because the interaction becomes more frequent and more energetic as the particle's velocity increases, so it needs to be taken into account when calculating dE/dx. The correction factor is usually expressed as an exponential function, which means that its magnitude increases exponentially with increasing velocity.