AST-1A Lecture Notes - Lecture 17: Technetium, Iodine-131, Decay Product
Document Summary
Uranium 235 235u 7. 04 x 108 yr, 0. 72% of all natural uranium. Uranium 238 238u 4. 47 x 109 yr, 99. 2745% of all natural uranium. Thorium 232 232th 1. 41 x 1010 yr. Radon 222 222rn 3. 82 days noble gas. Potassium 40 40k 1. 28 x 109 yrs. Made by rapid addition of neutrons in a very neutron rich environment, as might occur in a core collapse supernova. Evidence for a number of supernovae leading to the earth"s uranium. Uranium 238 decays to radium which decays to radon. Inert gas goes into atmosphere where it can be breathed in. Can accumulate in low areas because the atoms are heavy. Greatest threat from primordial radioactivity; leading cause of lung cancer after smoking. Carbon 14 14c 5730 yr, cosmic-ray interactions. Hydrogen 3 (tritium) 3h 12. 3 yr, cosmic-ray interactions with n and o. Beryllium 7 7be 53. 28 days cosmic-ray interactions with n and o.
