{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter3_20 - According to classical theory the oscillating...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
PHY3063 R. D. Field Department of Physics Chapter3_20.doc University of Florida Compton Scattering (1) The first direct evidence of the existence of photons was presented by A.H. Compton in 1923 . He directed a monochromatic beam of X-rays ( i.e. electromagnetic radiation) with wavelength, λ 0 , at a thin block of carbon and studied the intensity and wavelength of the scattered radiation as a function of the angle θ . He found that in addition to the wavelength λ 0 , which occurred at all angles, there was another component λ 1 which was longer than λ 0 . The amount of wavelength shift, ∆λ = λ 1 λ 0 , was the same regardless of the target material, implying that the effect involved electrons rather than the atom as a whole. Also ∆λ increased as the scattering angle θ increased. Classical Wave Theory:
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: According to classical theory the oscillating electric field of the incoming wave would set electrons in the target material into oscillations. These vibrating electrons would then reradiate electromagnetic waves in all directions, but at the same wavelength as the incident wave ( i.e. λ ). Compton Model: Compton adopted the suggestion by Einstein that light comes in parcels ( i.e. photons) with energy and momentum given by E γ = hf = hc/ λ and p γ = h/ λ He then calculated the properties of photon-electron 2-to-2 scattering γ + e-→ γ + e-using relativistic energy and momentum conservation, treating the photon as a massless particle, γ . θ λ 1 Incident X-ray Detector Carbon Block Wavelength λ x-axis y-axis z-axis E B Direction of Propagation λ 1...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online