Thickness of material to absorb electron beam

[amrian]

Homework Statement

Beam of electrons (charged particles!) is directed to copper absorber with known energy (E= 10MeV) and intensity (10^8(s*cm^2)^-1) . I need to find the thickness of absorber so that all electrons would be absorbed. Also under what conditions does it happen and what is absorbed dose then?

Homework Equations

D=(1.602*10^-10)* (fluence*E/mass thickness) (Gy)

The Attempt at a Solution

so to get absorber thickness should I mass stopping power multiply by copper density and then divide it from the beam energy?
is it thick foil condition?

 

[member 553083]

if it is, then dose is equal to absorber thickness multiplied by fluence multiplied by energy and divided by mass thickness?