Chapter 22-3 Nuclear Radiation By: Nate, Kristi, and Kayla

Penetrating and Shielding PenetratingShielding Alpha Low due to large mass and charge Can’t penetrate skin Shielded by paper Beta One hundred times that of Alpha Travels at speed of light Shielded by lead or glass Gamma Greatest penetrating ability Shielded by thick layers of concrete and/or lead

Penetrating and Shielding Cancer and genetic effects caused by DNA mutations are long-term radiation damage to living tissue The average exposure of radiation for people in the United States is 0.1 rem per year The maximum dose of radiation exposure for people for treatments is 0.5 rem Airline crews and people who live at high altitudes have increased exposure to radiation

Roentgens and Rems Roentgens  Units used to measure nuclear radiation  Equal to amount of radiation that produces 2 * 10 9 ion pairs when it passes through 1 cm 3 of dry air Rems  Units used to measure radiation damage to human tissue Quantity of ionizing radiation that does as much damage to human tissue as is done by 1 roentgen of high-voltage X rays

Radiation Detection Film badges – use exposure of film to measure approximate radiation exposure of people working with radiation Geiger-Müller Counters - instruments that detect radiation by counting electric pulses carried by gas ionized by radiation Scintillation counters – instruments that convert scintillating light to an electric signal for detecting radiation

Uses of Radioactive Nuclides Radioactive dating  process by which approximate age of an object is determined based on amount of certain radioactive nuclides present  Based on fact that radioactive substances decay with known half-lives  Age estimated by measuring either accumulation of daughter nuclide or disappearance of parent nuclide  Nuclides with longer half-lives used to estimate age of older objects like minerals and lunar rocks

Uses of Radioactive Nuclides Radioactive tracers  radioactive atoms that are incorporated into substances so that movement of the substances can be followed by radiation detectors  Detection of radiation from radioactive tracers can be used to diagnose cancer and other diseases  The artificial radioactive nuclide cobalt-60 Is used to destroy cancer cells

Uses of Radioactive Nuclides Agriculture  Radioactive tracers used to determine effectiveness of the fertilizer  Amount of radioactive tracer absorbed indicates amount of fertilizer absorbed  Nuclear radiation used to prolong shelf life of food  Gamma rays from cobalt-60 can be sued to kill bacteria and insects that spoil food

Nuclear Fission and Fusion Nuclear fission  Nucleus of a very heavy atom is spilt into more than one nuclei  Primary system powering nuclear reactors, nuclear missiles, and nuclear power submarines and aircraft carriers  Produces more waste than fusion 

Nuclear Fission and Fusion Nuclear fusion  Opposite of fission  High temperatures and pressures are used to combine light atoms to make heavier atoms  Primary process that fuels the sun and stars  shtml shtml

Nuclear Waste Radioactive waste has a half-life that ranges from a few months to hundreds of thousands of years Two types of containment for waste: on-site storage or off-site disposal Waste taken to large pools of water, then moved to dry casks (made of concrete and steel), and finally permanently moved underground (with the intention of never retrieving it)

Vocabulary Roentgen - a unit used to measure nuclear radiation Rem – the quantity of ionizing radiation that does as much damage to human tissue as is done by 1 roentgen of high-voltage X rays Film badges – use exposure of film to measure the approximate radiation exposure of those working with radiation

Vocab Cont’d Geiger-Müller Counters – instruments that detect radiation by counting electric pulses carried by gas ionized by radiation Scintillation Counters – instruments that convert scintillating light to an electric signal for detecting radiation Radioactive Dating – process by which the approximate age of an object is determined based on the amount of certain radioactive nuclides present

Vocab Cont’d Radioactive Tracers – radioactive atoms that are incorporated into substances so that movement of the substances can be followed by radiation detectors Nuclear Waste – produced by fission and fusion