What Does 'Per MeV' Mean in Muon Energy Loss Calculations?

[stakhanov]

I have a problem with units...

I have been looking at energy loss of muons in matter (from both ionizations and radition processes like bremsstrahlung). I have used an equation for the mean energy loss (for a muon of specified energy in a specified material) which gives an answer in units of g/cm^2/MeV. I am ok with converting this to cm/MeV I think (just divide by the density), but my problem is what does the 'per MeV' bit mean?

I have 50GeV muons going into concrete and from what I have read the mean range is ~45m. The equation I am using gives me an answer of 6.58cm/MeV (or 16.44g/cm^2/MeV) and I'm puzzling over how this gets converted into 45m.

Any help?

 

[mgb_phys]

MeV is million electron volts. Electron volts is the energy to raise a electron of charge through 1 volt and so 1ev= 1.6E-19J ( ie the charge on the electron in Coloumbs)
It is a more convenient sized unit of energy and mass when dealing with particles.

 

[sir-pinski]

It seems like you are struggling with unit conversions in your calculations. Let me try to explain it in simpler terms. The units of g/cm^2/MeV are a measure of energy loss per distance traveled by the muon, per unit energy. So, for every MeV of energy lost, the muon travels 6.58cm through the material. This is the average value, and it may vary depending on the specific energy of the muon and the material it is traveling through.

To convert this to a distance traveled, you can use the fact that energy is directly proportional to distance traveled. This means that for every increase in energy, there is a corresponding increase in distance traveled. So, if you have a muon with an energy of 50GeV, and you want to know how far it will travel in concrete, you can use the following equation:

Distance traveled = Energy lost / Energy per distance

In this case, the energy per distance is 6.58cm/MeV. So, for a muon with an energy of 50GeV, the distance traveled would be:

Distance traveled = 50GeV / 6.58cm/MeV = 7.6m

This means that the muon will travel approximately 7.6m through concrete before losing all of its energy. Keep in mind that this is an average value and may vary depending on the specific conditions.

I hope this helps clarify the units and conversions for you. If you are still having trouble, it may be helpful to consult with a physics tutor or your instructor for further assistance. Good luck with your calculations!