1. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV 3.1 Photons 3.1.3 Compton Scattering Scattering of an x-ray photon by a free electron in a conductor When the kinetic energy of electron is determined From the conservation of linear momentum law As if it were particle, we need to consider its energy and momentum

2. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Simplified schematic diagram of the Compton experiment Result of Compton experiment

3. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Momentum conservation along y-axis Momentum conservation along x-axis From above, unmeasurable angle Ф must be eliminated For X-ray photon energy

4. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV But ’ is only slightly greater than  so that  ’ is slight smaller than unity and  ’ is slightly larger than unity.

5. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV 3.1.4 Black Body Radiation Small hole acts as black bodyInserting cannot escape to outside

6. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Classical physics Probability of distribution Average E in black body Quantum physics Average E in black body (Density of E = Degree of freedom · average E)