![]() The energy of the photon particle is dependent on its electromagnetic frequency. They also have wave nature, for example, frequency and recurrence. Photons have energy and force similar to material particles. The American physicist Gilbert Lewis later authored the term photon for light quanta. The American physicist Arthur Holly Compton clarified (in 1922 and distributed in 1923) the frequency increment by considering X-rays as made out of discrete heartbeats, or quanta, of electromagnetic energy. The impact has ended up being one of the foundations of quantum mechanics, which represents both wave and particle properties of radiation. Check that these match the values provided above.Compton effect refers to the increase in the wavelength of photons (X-rays or gamma rays), due to their scattering by a charged particle (usually an electron). Use the graph and Equation 4-1 to determine the original gamma-ray energy and the rest mass of the electron. Plot the reciprocal of the scattered gamma-ray energy (1/E′ ) as a function of ( 1 - cos θ ). In a spreadsheet, plot the energy of the scattered peak as a function of angle and compare the results with Figure 4-1.ħ. For each measurement determine the centroid energy of the scattered peak.Ħ. Repeat Step 3, moving the detector assembly to different angles up to 1600 degrees.ĥ. Note: To increase the count rate, you can complete this experiment without the add-on detector collimator slit. For better angular resolution, use the detector collimator slit in the vertical orientation and extend the counting time until good statistics are achieved.Ĥ. Acquire a spectrum until a noticeable peak is visible. Place the detector with the collimated detector shielding on the scattering table. Starting with the 00 marking, orientate the detector assembly toward the aluminum scattering pillar. Do not have the source pointed at yourself or any other people working in the laboratory.ģ. Caution: Be sure to be aware of your surroundings. Ensure the collimated 137Cs source fixture is aligned at the 1800 mark and is pointing toward the aluminum scattering pillar. During this experiment, keep the source fixture fixed at this location. Configure the MCA settings and bias voltage as recommended in Experiment 1. Make sure that the detector is correctly calibrated for energy.Ģ. #Compton scattering software#Use the ProSpect software to connect to the detector. The units are barns per steradian, b/sr , where 1 barn = 10 -28 m 2.įigure 4-3: The differential cross section of Compton scattering for a photon energy of 662 keV. R 0 = 2.82 x 10 -15 m, the classical electron radius, and for 137CsĪ plot of the differential cross section, dσ/dΩ, is shown in Figure 4-3. The scattering probability as a function of angle is called the differential cross section, and for Compton scattering it is given theoretically by the Klein-Nishina formula (the units are square meters per steradian, m 2/sr): The expected energies are shown in Figure 4-2:įigure 4-2: The energy of the Compton-scattered photon as a function of scattering angle for an initial photon energy of 662 keV. Note: During this experiment you should work in keV, where the mass of the electron is 511 keV/c 2. Figure 4-1 illustrates the experimental setup, where the detector is positioned at about θ = 40°.įigure 4-1: Collimated 137Cs source and NaI detector positioned on the scattering table. In this experiment Eγ is measured as a function of θ for incident gamma rays of 662 keV from a 137Cs source. This may be rearranged as the equation for a straight line: The Compton scattering formula can be written as: Some of the energy of the photon is transferred to the electron, and the photon is scattered through an angle θ with reduced energy Eγ′. Demonstrate the possible range of scattered gamma-ray energies.Īs previously discussed in Experiment 1, in Compton scattering a photon of energy Eγ and momentum Eγ/c scatters inelastically from an electron of mass m 0c 2.Demonstrate how the gamma-ray energy varies following Compton scattering. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |