Compton\u27s \u27Crucial Test\u27 - Theoretical Preconceptions and Experimental Interpretation

Arthur Holly Compton, as a result of his own research and confidence in the validity of classical electrodynamics, was convinced in 1921 that homogeneous x-rays and gamma rays could be affected in only two possible ways when passing through matter: either they gave rise to truly scattered radiation of the same wavelength as that of the incident rays, or they excited fluorescent radiation of a longer wavelength. When Compton was led to carry out experiments using homogeneous x-rays and actually found secondary radiation of longer wavelength, he regarded his result as a crucial test between the truly scattered and the fluorescent radiation hypotheses and concluded that the latter was correct. More than a year later, late in 1922, Compton realized that he had found the strongest contemporary evidence for the quantum theory of radiation