Why are x-ray photons used in Compton experiment and not visible light photons?

Visible lights have enough energy to knock out electrons but energy is converted into KE of electrons emitted and initial photons are lost. If the photos are gone they can't scatter. Compton effect happens with visible light but its so less that it is unobservable. Any new photons are used by increasing KE of electrons. It becomes observable when photons energies are in range of 100eV that happens in case of X-rays

Dear student

X ray is used because 

It is due to Deflection of incident x ray .

There is lower energy in incident x – ray . 

Hope this will help 

Good Luck