However, gamma rays behaves like a particle with momentum and is Compton scattered. In order to be observed by the microscope, ray must be scattered within an angle of the cone. Since the electron is initially at rest, the total moment of the electron- photon system is the momentum of the photon.
and is Compton scattered. In order to be observed by the microscope, 
ray must be scattered within an angle 
of the cone. Since the electron is initially at rest, the total moment of the electron- photon system is the momentum of the photon. 
