Physics
Nuclear Physics
Nuclear physics is the study of the properties and behavior of atomic nuclei. It involves the study of nuclear reactions, nuclear energy, and the structure of atomic nuclei. This field has applications in energy production, nuclear medicine, and materials science.
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8 Key excerpts on "Nuclear Physics"
eBook - PDF- Samuel S. M. Wong(Author)
- 2008(Publication Date)
- Wiley-VCH(Publisher)
The book is aimed at physics students in their final year of undergraduate or first year of graduate studies in Nuclear Physics. There is enough material for a one-year course though it could be used for aone-semester course by leaving out some of the detail arid peripheral topics. The selection of material is guided in part by current interests in the field; no attempt has been made to give a complete account of everything that is known in Nuclear Physics. However, sufficient knowledge is provided here so that a student tnay then go to the library and obtain information on a particular nucleus or a special aspect of a topic. S. S. M. Wong Chapter 1 Introduction Nuclear Physics is the study of atomic nuclei. From deuteron to uranium, there are almost 1700 species that occur naturally on earth. In addition, large numbers of others are created in the laboratory and in the interior of stars. The main force responsible for nuclear properties comes from strong interaction. However, both wea.k and electromag- netic interactions also play important roles. For these reasons, Nuclear Physics serves as an important platform where basic properties of subatomic matter can be examined and fundamental laws of physics can be studied. We shall in this chapter give a brief history of the subject, its role in modern physics, and some of the general properties of nuclei we wish to study before going on into more detailed examinations in subsequent chapters. 1-1 Brief Early History of Nuclear Physics The beginning of Nuclear Physics may be traced to the discovery of radioactivity in 1896 by Becquerel. Almost by accident, he noticed that well-wrapped photographic plates were blackened when placed near certain minerals. To appreciate the significance of this discovery, it is useful to recall that the time was before the era of quantum mechanics. The only known fundamental interactions were gravity and electromagnetism.
eBook - PDFSuperstrings and Other Things
A Guide to Physics, Second Edition
- Carlos Calle(Author)
- 2009(Publication Date)
- CRC Press(Publisher)
421 23 Nuclear Physics BEYOND THE ATOM Quantum mechanics provided the mathematical foundation for our understanding of the properties of atoms. With this foundation in place, progress came quickly. Some physicists used the new theory to develop a more complete picture of the electronic properties of atoms, while others went on to apply the theory to the study of the atomic nucleus. We studied some of the basic properties of the nucleus in Chapter 8. Here we will examine nuclear transformations, nuclear energy, and the applications of Nuclear Physics to modern technology. RADIOACTIVITY As we saw in Chapter 8, atomic nuclei are composed of protons and neutrons bound by the strong force. Since the electric force has infinite range, diminishing gradually with distance, the positively charged protons feel the electrical repulsion of each and every one of the remaining protons in the nucleus. Since the nuclear force is a short range force, its influence dies out to almost nothing when the protons are separated by more than 10 − 14 m. If a nucleus contains too many protons, the total electric repulsion can overwhelm the nuclear attraction and a fragment of the nucleus (an alpha particle) will fly out. This is known as alpha decay . (Alpha is the Greek letter α .) However, if the nucleus contains a large number of neutrons, they contribute to the nuclear force without being affected by the electric force, as they are neutral. This is why light nuclei usu-ally have a similar number of protons and neutrons, such as 2 4 He , 3 7 Li , 6 12 C , and 8 16 O , whereas heavy nuclei require a great deal more neutrons to counterbalance the effect of the electrical repulsion. For example, 82 208 Pb contains 126 neutrons and 82 protons, and 79 197 Au has 118 neutrons and only 79 protons. There is a limit to the number of neutrons that a nucleus can have and still be stable.
eBook - PDF- Richard L. Myers(Author)
- 2005(Publication Date)
- Greenwood(Publisher)
Nuclear Physics Introduction Common reactions that transform matter are chemical in nature. These involve the inter- action of the electrons of substances. As one substance changes into another, chemi- cal bonds are broken and created as atoms rearrange. Atomic nuclei are not directly involved in chemical reactions but still play a critical role in the behavior of matter. Nuclear reactions involve the atom's nucleus. The nucleus contains most of the atom's mass but occupies only a small fraction of its vol- ume. Electrons have only about 1/2,000 the mass of a nucleon. To put this in perspective, consider that if the nucleus were the size of a baseball, the mean distance to the nearest electrons would be over 2 miles. At the start of the twentieth century, it was discovered that the nucleus is composed of positively charged protons and neutral neu- trons (see chapter 10). These particles are col- lectively called nucleons. During the last half of the same century, scientists learned how to harness the power of the atom. The deploy- ment of two atomic bombs brought a quick and dramatic end to World War II. This was followed by nuclear proliferation, the Cold War, and the current debate over developing a nuclear defense shield. The use of nuclear power as a source of clean, efficient energy continues to be debated. While nuclear power is used by many countries to fulfill their energy needs, accidents such as Chernobyl in the Ukraine and Three Mile Island in this country have dampened the public's enthusiasm for this energy source. Because of nuclear weap- ons and reactor accidents, people often per- ceive the term "nuclear" negatively, but there are many positive aspects to nuclear science. Nuclear medicine is used extensively for both diagnostic and therapeutic procedures. Radio- metric dating is an invaluable tool to scientists who use this method for applications such as dating relics, determining the age of the Earth, and studying climate change.
eBook - ePubRenewable Energy
A First Course
- Robert Ehrlich, Harold A. Geller, John R. Cressman(Authors)
- 2022(Publication Date)
- CRC Press(Publisher)
Nuclear Power Basic ScienceDOI: 10.1201/9781003172673-3Contents
- 3.1 Introduction
- 3.2 Early Years
- 3.3 Discovery of the Atomic Nucleus
- 3.4 Mathematical Details of the Rutherford Scattering Experiment
- 3.5 Composition and Structure of the Atom and Its Nucleus
- 3.6 Nuclear Radii
- 3.7 Nuclear Forces
- 3.8 Ionizing Radiation and Nuclear Transformations
- 3.9 Nuclear Mass and Energy
- 3.10 Nuclear Binding Energy
- 3.11 Energy Released in Nuclear Fusion
- 3.12 Mechanics of Nuclear Fission
- 3.13 Mechanics of Nuclear Fusion
- 3.14 Radioactive Decay Law
- 3.15 Health Physics
- 3.16 Radiation Detectors
- 3.17 Radiation Sources
- 3.18 Impacts of Radiation on Humans
- 3.19 Summary
- Problems
- References
3.1 Introduction
Some books on renewable energy do not go into the subject of nuclear energy, but it is important to include it based on the need to compare renewable energy technologies with the other available energy sources, including nuclear. Moreover, some would argue that nuclear is in fact a form of renewable energy or, at least, a useful supplement to it. In this first of two chapters on nuclear energy, we consider the basic science, an understanding of which is essential to the technological issues considered in the following chapter. This chapter begins with a historical overview and then proceeds with the development of the basic science needed to understand nuclear energy; it also delves into the consideration of nuclear radiation, including its effects on humans.3.2 Early Years
As with any new science, the early years of nuclear science were a period of confusion and accidental discovery. Although there were important contributions by many pioneers, we highlight here those by three individuals: Henri Becquerel, Marie Curie, and, especially, Ernest Rutherford. Antoine Henri Becquerel (who, along with Marie and Pierre Curie, was awarded the Nobel Prize in Physics in 1903) is generally acknowledged to be the discoverer of radioactivity. Becquerel’s discovery was entirely accidental and occurred one day in 1896, while investigating phosphorescence in uranium salts (Becquerel, 1896). He happened to have placed some uranium salt above some photographic plates that were wrapped in very thick black paper to prevent light exposure. Becquerel found that the plates became fogged nevertheless. He also noted that
eBook - PDF- James Shipman, Jerry Wilson, Charles Higgins, Bo Lou, James Shipman(Authors)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
267 CHAPTER 10 Nuclear Physics “John,” I said, “when you get older, you’re going to understand a lot of things you don’t understand now.” “You must mean Nuclear Physics,” he said. “I can hardly wait.” ● Kurt Vonnegut, American writer (1922–2007) T he atomic nucleus and its properties have had an important impact on our society. For example, the nucleus is involved with archeological dating, diagnosis and treatment of cancer and other diseases, chemical analysis, radiation damage and nuclear bombs, and the generation of electricity. This chapter discusses these topics and includes Highlights on The Discovery of Radioactivity, and Nuclear Power and Waste Disposal. An appropriate way to begin the study of Nuclear Physics is with a brief his- tory of how the concept of the element arose and how elements and their nuclei are expressed by symbols. 10.1 Symbols of the Elements Key Questions ● ● What original “elements” did Aristotle think composed all matter on the Earth? ● ● Why are some element symbols very different from their names? For example, carbon is C, but silver is Ag. < Technetium-99, a laboratory- produced radioactive isotope, is often used in brain scans. Here, a color-enhanced scan has been superimposed on the back of a woman’s head.
- Andrei D. Polyanin, Alexei Chernoutsan(Authors)
- 2010(Publication Date)
- CRC Press(Publisher)
Chapter P8 Elements of Nuclear Physics The idea that practically the entire mass of an atom is concentrated in its positively charged nucleus of infinitesimally small dimensions is due to Rutherford’s experiments (see Chap-ter P6). Since the dimensions of nuclei turned out to be by five orders less than those of atoms, it can be assumed, in the framework of atomic physics, that the nucleus is a point Coulomb center. Actually, the nucleus is a complex structure formed by strongly interacting particles (several ones or hundreds) obeying the laws of quantum mechanics and quantum statistics. The nuclei can undergo radioactive transformations, participate in nuclear reac-tions, disintegrate, and merge with other nuclei. The characteristic energies in that nuclear world are measured in millions of electron-volts, which explains why nuclei appear as stable objects in atomic processes with energies up to several hundred electron-volts. P8.1. Basic Properties of Nuclei P8.1.1. Characteristics of Nuclei ◮ Nuclear Composition. The atomic nucleus consists of protons and neutrons—particles collectively named nucleons . The proton is a subatomic particle with positive charge e and mass m p = 1836 . 15 m e , where m e is the electron mass. The neutron is an electrically neutral particle whose mass is slightly greater than that of the proton: m n = 1838 . 68 m e . In its free state, the neutron is unstable in the sense that within 15.5 minutes, on the average, it turns into a proton after emitting an electron and an antineutrino: n → p + e + tildewide ν . The spin* of both the proton and neutron is equal to 1 / 2 , which means that they belong to the class of fermions. Both the proton and the neutron possess nonzero magnetic moments: μ p = 2 . 793 μ N and μ n = – 1 . 91 μ N , where μ N = e planckover2pi1 / 2 m p is the so-called nuclear magneton ( μ N = μ B / 1836 . 15 ).
eBook - PDF- Stephen Thornton, Andrew Rex, Carol Hood, , Stephen Thornton, Stephen Thornton, Andrew Rex, Carol Hood(Authors)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
We then study the properties of the nucleus and its constituents, the neutrons and protons. Finally, we discuss nuclear forces and why some nuclei are stable and others are unstable, that is, radioactive. The study of nuclear radioactivity has many impor- tant applications, which we shall discuss in Chapter 13. 12.1 Discovery of the Neutron Although Rutherford proposed the atomic structure with the massive nucleus at the center in 1911, it was not until 1932 that scientists knew which particles com- pose the nucleus. This study is still ongoing (see Chapter 14), because as physi- cists strive to find the essence of the fundamental nuclear particles, they con- tinue to find even more particles. The Atomic Nucleus 12 Copyright 2021 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 436 Chapter 12 The Atomic Nucleus In the early 1900s the nucleus had been erroneously assumed to consist of protons and electrons. However, there are several reasons why electrons cannot exist within the nucleus. 1. Nuclear size: We showed previously, in Examples 5.10 and 5.11, that in or- der to confine an electron in a space as small as a nucleus, the uncertainty principle puts a lower limit on its kinetic energy that is much larger than any kinetic energy observed for an electron emitted from nuclei. 2. Nuclear spin: Protons and electrons have spin 1y2. If a deuteron (mass number A 5 2 and atomic number Z 5 1) consists of protons and elec- trons, the deuteron must contain 2 protons and 1 electron in order to have A 5 2 and Z 5 1.
eBook - PDF- Michael Tammaro(Author)
- 2019(Publication Date)
- Wiley(Publisher)
A typical nuclear reaction releases roughly a million times the energy of a chemical reaction, so the potential for energy production is enormous. Indeed, nuclear reactors have been generating power since 1954, and currently they supply the world with 14% of its electricity. This photo was taken looking down at the glowing core of the Advanced Test Reactor (ATR) at the Idaho National Laboratory. The core is submerged in water, which is the moderator of the fission chain reaction. The ATR has a maximum power of 250 MW, but it is not used for generating electricity. Rather, the ATR is a research reactor, whose primary purpose is to test materials to be used in power reactors. The blue glow is known as Cerenkov radiation, which is emitted whenever a charged particle traveling in a medium moves faster than the speed of light in that medium. Science Source Nuclear Physics 31 850 Nuclear Structure | 851 31.1 Solve problems dealing with nuclear structure. 31.1.1 Identify a nucleus in symbolic notation. 31.1.2 Solve problems using the approximate formula for the radius of a nucleus. In our study of atomic physics in Chapter 30, we paid little attention to the atomic nucleus, which resides at the atom’s center. This made sense at the time because the nucleus has negligible effect on the electronic orbitals and the way that atoms bond to form molecules. The nucleus is fascinating in its own right, however, and Nuclear Physics has numerous applications in technology and medicine. The atomic nucleus contains positively charged particles called protons with charge e + and neutral particles called neutrons. Neutrons and protons are referred to collectively as nucleons. Table 31.1.1 compares the masses and charges of the proton, neutron, and electron.
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