Radiation What is there to fear?

Types of radiation Particulate Electromagnetic Alpha particles Beta particles Neutrons Fission Fragments Electromagnetic Ionizing Non-ionizing

Particulate Radiation Alpha particles Helium nuclei penetrate < 10 cm in air, 60 m in tissue stopped by paper Beta particles Electrons Penetrate a few mm into tissue Neutrons Fission Fragments

Electro-Magnetic Radiation Penetrating radiation: X-rays  rays

Radiation Sources Radioactive decay High energy collisions Particle acceleration Astrophysical processes

Definitions 1 Becquerel (Bq) = 1 disintegration/second (dps) 1 Curie = 3.7 x 1010 dps 1 Röntgen = amount of ionizing radiation that produces 1 esu/cm3 in dry air 1 rad (Röntgen absorbed dose) = 100 erg/gm 1 Gray (Gy) = 100 rads = 1 Joule/kg Dose = 0.869 f R f = mass absorption coefficient/air Rem (biological equivalent dose) = rads x QF QF (quality factor)  # ion pairs / cm 1 Sievert (Sv) = 100 rem

Half Life Time for half the original sample to decay N = N0 e-0.693 T1/2 t

How Radiation Kills Ionizing/penetrating radiation breaks chemical bonds Particles/ionizing radiation deposits energy Lethal dose: 500 rad kills half

Can You Avoid Radiation? No.

The Atom Bomb Runaway fission of U235 or Pu239 U235 + n0 fragments + 2.4n0 + 193 MeV Pu239 + n0 fragments + 2.9n0 + 199 MeV MeV: 1.6 x 10-6 erg 100 kg of U235  8x1022 erg ~ 2 MT

The Hydrogen Bomb A 3 stage weapon: Pu239 fission or high explosives compresses D2+H3 D2+H3  He4 + n0 + 14.1 MeV n0 release triggers U238 fission in casing 100 kg of D+T  2.3x1023 erg ~ 5 MT