Projection Radiography (X-Ray) Instructors: Brian Fleming and
Ioana Fleming [email protected], [email protected] January 7th,
2010 Slide 2 Today X-Ray production Interaction with matter /
tissue Instrumentation Applications Slide 3 1. Atomic Structure
Balanced == Neutral -- No Charge! Missing Electron == ? Extra
Electron == ? Slide 4 Electrons Orbiting in shells Slide 5 Electron
Binding Energy Atoms ground state lowest energy configuration Basic
principle: bound energy < unbound energy + electron energy
Binding energy is difference Binding energy of hydrogen electron:
13.6 eV 1 eV is the kinetic energy gained by an electron that is
accelerated across a one (1) volt potential Slide 6 Ionization and
Excitation Ionization is knocking" an electron out of the atom
creates 1 electron and 1 ion (what charge?) Excitation is knocking"
an electron to a higher orbit Slide 7 Characteristic Radiation What
happens to ionized or excited atom? Return to ground state by
rearrangement of electrons Causes atom to give of energy Energy
given off as radiation infrared light x-rays Slide 8 Ionizing
Radiation Radiation with energy > 13.6 eV ionizes H Energy
required to ionize: Air: 34 eV Lead: 1 keV Tungsten: 4 keV (average
binding energies) Radiation energies in medical imaging 30 keV -
511 keV can ionize 10 - 40,000 atoms Slide 9 Particulate Radiation
Any subatomic particle (proton, neutron, electron) can be
considered to be ionizing radiation (nuclear, beta) if it possesses
enough kinetic energy to ionize an atom An electron accelerated
across 100 kV potential difference yields a 100 keV electron Slide
10 Ion Drives Slide 11 Ion Engines Slide 12 Medical Particle Beams
Slide 13 What are X-Rays ? Electromagnetic EM Radiation radio,
microwaves, infrared, visible light, ultraviolet x-rays, gamma rays
Particle / photon: E = h * Planck's constant h = 4.14 * 10 -15
eV-sec f is frequency Electromagnetic wave: = c / C = 3 * 10 8
meters/sec; speed of light X-Rays vs. light vs. radio waves Slide
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