The document discusses various types of ionizing radiation and their interactions with matter. It describes electromagnetic radiation as composed of photons that can interact via photoelectric effect, Compton scattering, pair production, and other processes. Compton scattering results in energy transfer between photons and recoil electrons. The probability of interaction depends on photon energy and material properties like atomic number. Higher energy photons have a greater chance of depositing energy through secondary electrons.

1. DR. VIKAS JAGTAP JR I DR. LEE SR I

7. All electromagnetic waves travel at the same speed The speed of light: 300,000 Km/s trough crest

8. Wavelength (length/cycle) Wavelength (  ): the length of one complete cycle trough crest

9. Wavelength (length/cycle) Amplitude : 1/2 height between trough and crest Amplitude trough crest

10. Wavelength (length/cycle) Frequency (  ): the number of cycles/second Amplitude trough crest

29. Material Density(g/cm3) Atomic no no,. Of electrons per gram hydrogen 0.0000899 1 6 × 10 carbon 2.25 6 3.01 oxygen 0.001429 8 3.01 copper 8.9 29 2.75 Effective atomic no. fat 0.916 5.92 3.48 muscle 1.00 7.42 3.36 water 1.00 7.42. 3.34 bone 1.85 13.8 3.00 air 0.001293 7.64 3.01

30. Bone Hydrogen Water Muscle

33. Increasing share of total energy is taken up recoil electron

39. This has several important implications in designing radiation protection. The maximum energy of photons with 90° scatter is 0.511 MeV while that for 180° scatter ( i.e.. Back scatter) is 0.255 MeV . The energy of the photons scattered at angles <90 ° will be more than .511 MeV and will gradually approach the incident photon energy Energy of the scattered radiation is independent of the incident beam energy

41.    0 0 0 0 0 7 50 95 84 16 100.00 50 50 24.00 23 77 10.00 6 94 4.00 0 100 0.150 0 93 0.060 0 50 0.026 0 5 0.01 Relative no. of interaction Photon energy (MeV)

55. Applications This leads to dosimetric inaccuracies when using air containing ion chambers. Polarization in heavier atomic weight elements. This leads to a “smudging” of the Bragg's peak which is not seen in electrons. The low mass of the electron leads to greater scattering. This is of practical importance as radioactive isotopes which are produce high energy beta radiation are better stored in low atomic number materials e.g. plastics as they will lead to lesser bremsstrahlung radiation. Also higher atomic number elements are better for x ray production. The amount of radiative loss is proportional to the square of the atomic number of the material This leads to the phenomenon of greater ionization in soft tissues relative to bones. Ionization and excitation are more for low atomic materials

69.    0 0 0 0 0 7 50 95 84 16 100.00 50 50 24.00 23 77 10.00 6 94 4.00 0 100 0.150 0 93 0.060 0 50 0.026 0 5 0.01 Relative no. of interaction Photon energy (MeV)