1 / 17

ABC's of Radiation: Understanding Nuclei, Stability, and Decay

Learn about the basics of radiation, including the structure of the nucleus, the concept of nuclear stability, and the different types of decay. Discover how radiation can affect our health and the sources of radiation exposure in our everyday lives.

sruben
Download Presentation

ABC's of Radiation: Understanding Nuclei, Stability, and Decay

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ABC’s of RadiationHoward MatisLawrence Berkeley National Laboratory AAPT 2005 - Albuquerque Howard Matis - hsmatis@lbl.gov 1

  2. AAPT 2005 - Albuquerque • Howard Matis - hsmatis@lbl.gov • 2 • What is a Nucleus? • Quarks determine if proton or neutron • Neutrons • Protons • Protons determine chemical propertiesRatio of neutrons to protons make a nucleus stable or unstable

  3. Examples - Isotopes • Uranium-238 (23892U) • 92 protons, 146 neutrons, mass 238 • Uranium-235 (23592U) • 92 protons, 143 neutrons, mass 235 • Hydrogen (11H) • 1 proton, 0 neutrons, mass 1 • Deuterium (21D) • 1 proton, 1 neutron, mass 2 • Tritium (31T) • 1 proton, 2 neutrons, mass 3

  4. Nuclear Stability • N = # of Neutrons • Z = # of Protons • White are the stable nuclei • For light nuclei, stable nuclei have N=Z • If too many protons, then a proton will turn into a neutron • If too many neutrons, a neutron will turn in a proton

  5. How Does it Decay? • Alpha - lose an alpha particle (a - helium nucleus)Beta - emit a beta particle (b - electron or anti-electron)Gamma - emit a gamma (g or photon or light particle)

  6. Alpha Decay • Alpha particle or helium nucleus emitted • Nucleus changes mass by four units and charge by two units • Alpha particle easily stopped • 4 x nucleon mass • +2 Charge • Big

  7. Beta Decay • Beta minus - neutron converts to electron and anti-neutrino • Beta plus - proton converts to a anti-electron and neutrino • Nucleus changes charge but not mass number • Radiation moderately penetrating • +1 charge • Small electron

  8. Gamma Decay • Nucleus changes energy level - emits gamma ray or photon • Nucleus stays the same • Very penetrating • Very small • Neutral

  9. Penetrating Properties of • Ionizing Radiation

  10. Cosmic RaysAnother form of Radiation • Comes from outside the earthParticles from the sun • Star dust - from supernova - exploding starsConsists of protons and neutrons

  11. Sources of Radiation • Average radiation exposure in the United States - 360 mrem Very location dependent

  12. Additional Sources • Plane travel • Living at high elevation - Albuquerque has 2x cosmic radiationSoil • Medical x-rays • Occupational exposure

  13. Is radiation bad for you? • Too difficult to directly measure risk of low level • Use high exposure studies to determine radiation damage • Extrapolate from high exposure to low • Model assumes that body does not heal from radiation exposure • Similar to calculating the risk of death from a pin prick by extrapolating from a knife wound

  14. Relative Risk1 in a million fatality • 40 tablespoon peanut butter (aflotoxin) • 2 days in New York City (air quality) • 3 mrem radiation (cancer) • 1 mile on motorcycle (collision) • 300 miles in car (collision) • 10 charbroiled steaks • Smoking 1 cigarette

More Related