OBSERVATION. ‘One peak is located at the wavelength which is the wavelength of the incident beam. The other peak is located at some other wavelength, The two peaks are separated by which depends on the scattering angle of the outgoing beam (in the direction of observation). The separation is called the Compton shift.”
https://opentextbc.ca/universityphysicsv3openstax/chapter/the-compton-effect/#:~:text=The%20Compton%20effect%20is%20the,wavelength%20of%20the%20incident%20radiation