Xrays having an energy of 260 keV undergo Compton scattering
Solution
a)
Compton shift is,
Dl = (h/mec)(1 -cosq) = (0.00243nm)(1 - cos42°)
=0.0006241 nm
=0.00062*10^-9 m
b)
hc = (6.63×10-34Js)(3.0×108m/s) =2.0×10-25Jm
Convert it into eV
hc =(2.0×10-25Jm)/(1.6×10-19J/eV) =1.24×10-6eV m
The wavelength of the incoming x-ray is
l0 = hc/E0 =(1.24×10-6eV m) / (2.60×105eV) =4.76×10-12m = 0.00476nm
The wavelength of out going wave is
l = l0 + Dl =0.00476nm + 0.000624 nm = 0.005384 nm.
Photons of this wavelength have energy:
E = hc/l = (1.24×10-6eVm) / (5.38×10-12m) = 0.230×106eV= 230 keV.
c)
The energy after the scattering is theenergy of the outgoing x-ray, plus the kinetic energy of therecoiling electron, plus the rest energy of the electron. These must be equal,
therefore E0 + mec2= E + KE + mec2
or
KE = E0 - E = 260keV - 230 keV = 30keV.
