radioactivity detection - radioactivity found everywhere

• Geiger counter - creates pulse whenever radiation enters tube
  • radiation causes matter to ionize, create electrical current
• scintillation counter - measures radiation based on light produced when radiation hits a phosphor
  • phosphor - substance that gives off light when hit by radiation
• radiotracer - radioisotope used to trace the path of an element through a reaction

nuclear fission - fragmenting heavy nuclei to generate energy

• chain reactions - 1 leading to another, multiplying number of reactions
• critical mass - amount of fissionable material needed to maintain chain reaction
  • supercritical mass - in excess of critical mass
• control rods - absorbs neutrons to regulate chain reaction
  • keeps reaction self-sustained, prevents overheating
• moderator - slows down neutrons
• cooling liquid - carries off heat generated by fission (can also work as the moderator)
• problems w/ storing the radioactive wastes from fission

nuclear fusion - combining/fusing light nuclei

• used by sun to produce energy
• doesn’t produce any radioactive substances
• requires at least 40,000,000 K to start reactions
• tokamak - uses strong magnetic fields to contain/heat reaction
  • only reached temperatures of 3,000,000K

biological effects of radiation - radiation >> excitation or ionization of matter

• excitation >> electrons go to higher energy states, moves more
• ionization >> electron gets removed from atom
  • creates free radicals (has 1+ unpaired electrons)
  • can attack other compounds
• gray (Gy) - absorption of 1J of energy per kg of tissue
  • 100 rads = 1 Gy
• radon - radioactive noble gas fromed from uranium-238
  • no direct chemical effects when inhaled
  • short half-life >> can produce radiation very quickly