Figure: 21-01 Title: Radioisotope scanning. Caption: A gamma ray detector scan of a normal human heart, obtained following intravenous injection of the radioisotope thallium-201, a gamma emitter. The donut-shaped pink and red area represents uptake of the radioisotope by healthy heart muscles.

Figure: 21-02 Title: The belt of stability. Caption: The number of neutrons is graphed versus the number of protons for stable nuclei. As the atomic number increases, the neutron-to-proton ratio of the stable nuclei increases. The stable nuclei are located in the shaded area of the graph known as the belt of stability. The majority of radioactive nuclei occur outside this belt.

Figure: 21-03 Title: Proton and neutron changes in the nuclear process. Caption: The graph shows the results of alpha emission, beta emission, positron emission, and electron capture on the number of protons and neutrons in a nucleus. Moving from left to right or from bottom to top, each square represents an additional proton or neutron, respectively. Moving in the reverse direction indicates the loss of a proton or neutron.

Figure: 21-04 Title: Nuclear disintegration series for uranium-238. Caption: The 238U nucleus decays to 234Th. Subsequent decay processes eventually form the stable 206Pb nucleus. Each blue arrow corresponds to the loss of an  particle; each red arrow corresponds to the loss of a  particle.

Figure: 21-05 Title: Schematic drawing of a cyclotron. Caption: Charged particles are accelerated around the ring by applying alternating voltage to the dees.

Figure: 21-06 Title: The Fermi National Accelerator Laboratory at Batavia, Illinois. Caption: Particles are accelerated to very high energies by circulating them through magnets in the ring, which has a circumference of 6.3 km.

Figure: 21-07 Title: Radioactive decay of strontium-90. Caption: Decay of a 10.0-g sample of strontium-90 (t1/2 = 28.8 yr).

Figure: 21-10 Title: Geiger counter. Caption: Schematic representation of a Geiger counter.

Figure: 21-12a Title: Positron emission tomography (PET). Caption: (a) A patient is injected with a solution of a radiolabeled compound that quickly moves to the brain. Radioactive nuclei within the compound emit positrons. The PET instrument measures the positron emissions and develops a three-dimensional image of the brain. (b) PET images of the human brain showing areas active in obsessive-compulsive behavior. Each view represents a different cross section of the brain. The red and yellow areas are the active areas, as indicated by blood flow detected by the radioactive tracer.

Figure: 21-13 Title: Nuclear binding energies. Caption: The average binding energy per nucleon increases to a maximum at a mass number of 50 to 60 and decreases slowly thereafter. As a result of these trends, fusion of light nuclei and fission of heavy nuclei are exothermic processes.

Figure: 21-14 Title: Diagram of uranium-235 fission. Caption: This diagram shows just one of many fission patterns. In this process 3.5  10–11 J of energy is produced per uranium-235 nucleus.

Figure: 21-15 Title: Chain fission reaction. Caption: Assuming that each fission produces two neutrons, the process leads to an accelerating rate of fission, with the number of fissions potentially doubling at each stage.

Figure: 21-16 Title: Subcritical and supercritical mass. Caption: The chain reaction in a subcritical mass soon stops because neutrons are lost from the mass without causing fission. As the size of the mass increases, fewer neutrons are able to escape. In a supercritical mass, the chain reaction is able to accelerate.

Figure: 21-17 Title: An atomic bomb design. Caption: A conventional explosive is used to bring two subcritical masses together to form a supercritical mass.

Figure: 21-19 Title: Diagram of a reactor core. Caption: The diagram shows fuel elements, control rods, and cooling fluid. A moderator, used to slow the neutrons, is also present.

Figure: 21-20 Title: The basic design of a nuclear power plant. Caption: (a) Heat produced by the reactor core is carried by a cooling fluid such as water or liquid sodium to a heat exchanger in which steam is generated. The heat exchange liquid moves in a closed loop. The steam produced is used to drive an electrical generator. (b) A nuclear power plant in Salem, New Jersey. Notice the dome-shaped concrete containment shell.

Figure: 21-21 Title: A tokamak fusion test reactor. Caption: A tokamak is essentially a magnetic "bottle" for confining and heating nuclei in an effort to cause them to fuse.

Figure: 21-22 Title: Penetrating radiation. Caption: The relative penetrating abilities of alpha, beta, and gamma radiation.

Figure: 21-23 Title: Sources of the average annual exposure of the U.S. population to high-energy radiation. Caption: The total average annual exposure is 360 mrem. (Data from "Ionizing Radiation Exposure of the Population of the United States," Report 93, 1987, National Council on Radiation Protection.)

Figure: 21-25-01UNE2 Title: Exercise 21.2 Caption: Graph of the number of neutrons versus the number of protons.

Figure: 21-25-02UNE4 Title: Exercise 21.4 Caption: Graph showing the decay of molybdenum-88 as a function of time.

Figure: 21-25-03UNE6 Title: Exercise 21.6 Caption: Decay series for a fission process.

Figure: 21-25-04UNE73 Title: Exercise 21.73 Caption: Synthesis of labeled methyl acetate.

Figure: 21-T01 Title: Table 21.1 Caption: Properties of Alpha, Beta, and Gamma Radiation.

Figure: 21-T02 Title: Table 21.2 Caption: Common Particles in Radioactive Decay and Nuclear Transformations.

Figure: Title: Table 21.3 Caption: The Number of Stable Isotopes with Even and Odd Numbers of Protons and Neutrons.

Figure: 21-T04 Title: Table 21.4 Caption: The Half-Lives and Type of Decay for Several Radioisotopes.

Figure: 21-T05 Title: Table 21.5 Caption: Some Radionuclides used as Radiotracers.

Figure: 21-T06 Title: Table 21.6 Caption: Mass Defects and Binding Energies for Three Nuclei.

Figure: 21-T07 Title: Table 21.7 Caption: Effects of Short-Term Exposures to Radiation.

Figure: 21-T08 Title: Table 21.8 Caption: Some Radioisotopes Used in Radiation Therapy.