Compton Scattering Reporter: Hui He

Outline Theory Experimental setup Experimental results (1) Calibration (2) Angular Distribution of the 137 Cs Source (3) Total Cross Section (4) the Energy of the Scattered Photon (5) the Differential Scattering Cross Section Conclusion

Theory Conservation of momentum and energy:

The quantum mechanical calculation for Compton scattering yields the Klein-Nishina formula: The total cross section is:

Experimental setup

Experimental Results 1. Calibration basic fitting of Energy vs Channel

2. Angular Distribution of the 137 Cs Source

the distribution of the photons emitted by the source satisfy Gaussian distribution, which is highly concentrated the highest grossing rate lies in closer to -1 0 rather than 0 0

3. the Total Cross Section for Compton Scattering

Calculation:

4. the Energy of the Scattered Photon

Experimentally, we have:

In theory

5. the Differential Scattering Cross Section To get the right value of differential scattering cross section, two corrections should be made here. (1) the energy dependence of the efficiency of the NaI should be considered. The linear attenuation coefficient of NaI can be expressed empirically, between 100 and 700 KeV, as The probability that a scattered photon of energy E will be recorded by the NaI is given by:

(2) multiple Compton Scattering V is the volume of the scattering, R=2.83cm, is the linear attenuation coefficient at the scattered photon energy, :

With the two corrections:

In theory:

Conclusion we have verified the energy dependence of gamma radiation upon scattering angle Also, we calculated the total cross section as well as the differential scattering cross section for Compton Scattering The differential scattering cross section we obtained from the experimental data is similar to the theoretical one calculated from the Klein-Nishina formula but there is still many differences because of the influence of noises and operation error

Thank you !