{"id":20,"date":"2018-11-02T06:18:12","date_gmt":"2018-11-02T06:18:12","guid":{"rendered":"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/?post_type=chapter&#038;p=20"},"modified":"2019-04-29T08:58:14","modified_gmt":"2019-04-29T08:58:14","slug":"introduction-to-nuclear-physics","status":"publish","type":"chapter","link":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/chapter\/introduction-to-nuclear-physics\/","title":{"rendered":"Introduction to Nuclear Physics"},"content":{"raw":"<div><span style=\"float: right\"><a href=\"https:\/\/youtu.be\/9cyDFNPPOYU\" target=\"_blank\" rel=\"noopener\"><img src=\"http:\/\/epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/2018\/11\/download.png\" alt=\"epgp books\" width=\"75px\" height=\"75px;\" \/><\/a>\r\n<\/span><\/div>\r\n<div>\r\n\r\n<strong>\u00a0 \u00a0 Learning Outcomes<\/strong>\r\n\r\n&nbsp;\r\n\r\nFrom this module students may get to know about the following:\r\n<ul>\r\n \t<li>The aim and scope of nuclear physics.<\/li>\r\n \t<li>The development of nuclear physics.<\/li>\r\n \t<li>Present understanding of nuclear physics.<\/li>\r\n \t<li>Useful terms and basic units of measurements used in nuclear physics<\/li>\r\n<\/ul>\r\n<strong style=\"text-align: initial;font-size: 1em\">\u00a0 \u00a0 1. Aim and scope of nuclear physics<\/strong>\r\n\r\n&nbsp;\r\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">The nuclear physics is the branch of physics in which the study of <\/span>atomic<span style=\"text-align: initial;font-size: 1em\"> nucleus, its constituents and the interactions happening among them is done. Right from the discovery of radioactivity in 1996 by Henri Becquerel, <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> physics has evolved with time and now its applications can be seen in many fields. The most common application of nuclear physics is in power generation, but its use in many other fields like medical sector, agriculture sector, archaeology, industries <\/span>and<span style=\"text-align: initial;font-size: 1em\"> geology has now made the study of nuclear physics important. Though the aims and objectives of studying nuclear physics are not limited to <\/span>few<span style=\"text-align: initial;font-size: 1em\"> domains, <\/span>but<span style=\"text-align: initial;font-size: 1em\"> the importance of learning nuclear physics can be understood in the following ways :<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">1.1 Understanding the origin of elements: <\/strong><span style=\"text-align: initial;font-size: 1em\">The knowledge of nuclear physics, helps us in understanding the origin of our world and the elements in it. Our Universe is believed to be formed in the \u2018Big Bang\u2019 happened some 14 billion years ago. In the early <\/span>Universe<span style=\"text-align: initial;font-size: 1em\"> only the light elements like hydrogen and helium along with trace amounts of lithium and beryllium were formed. Then as the cloud of cosmic dust and gases from the Big Bang cooled, stars formed, which then grouped together to form galaxies. The other elements heavier than the hydrogen and helium found in nature were created in nuclear reactions in these stars and in huge stellar explosions known as supernovae. Few examples are :<\/span><\/p>\r\n\r\n<\/div>\r\n<img class=\"wp-image-24 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled.png\" alt=\"\" width=\"839\" height=\"172\" \/>\r\n<div>\r\n\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong>1.2\u00a0\u00a0 Understanding the origin of various properties of elements <\/strong>: The nuclear physics not only accounts for the formation of elements in the universe, it also explains as how the elements gain various properties like mass, charge spins etc. To our basic understanding, the nucleus consists of protons and neutrons. The protons are positively charged while the neutrons are neutral. So the charge on the nucleus is just the algebraic sum of the charge on the protons inside it. Also as the proton and neutron are massive particles (mp ~ mn), so almost all the mass of elements in the universe is due to mass of the nuclei. The proton and neutron are fermionic particles with spin 1\/2, so all the nuclei have spins. The arrangement of protons and neutrons inside the nucleus is governed by the strong interaction acting between them inside the nucleus. So depending upon the number of protons and neutrons and their distribution inside, the nuclei have different shapes and sizes. So nuclear physics in general can account for almost all the observed properties of elements in the universe.<\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong>1.3 Understanding the origin the forces in Universe<\/strong>: The four basic forces in the Universe are the strong force, electromagnetic force, weak force and the gravitational forces. These forces vary in\u00a0<span style=\"text-align: initial;font-size: 1em\">strength and their range of applications. The modern days understanding of nuclear and particle physics suggest that all these four forces at the fundamental level work through some mediating particle. The strong forces work via exchange of \u2018gluons\u2019, The weak force via \u2018W\/ G bosons, electromagnetic force via \u2018photons\u2019 and the gravitational force via \u2018graviton\u2019. Working at the fundamental level, the scientists have found that all these four forces are not different but have a single origin. Through Grand Unified Theory (GUT) they have been able to unify the strong force, electromagnetic forces <\/span>and<span style=\"text-align: initial;font-size: 1em\"> the weak forces successively.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">1.4 Improving the quality of life on earth <\/strong>:<span style=\"text-align: initial;font-size: 1em\"> The nuclear physics is not only unfolding the mysteries of the University but is helping to improve the quality of life on earth. Nowadays the nuclear techniques are being used by almost every industry. The biggest example of nuclear application is in power generation in <\/span>Nuclear<span style=\"text-align: initial;font-size: 1em\"> Power plant. The other big area using <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> techniques is the medical sector, where a number of sophisticated diagnostic and therapeutic procedures based on <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> techniques have been developed.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">2<\/strong><span style=\"text-align: initial;font-size: 1em\">.<\/span><strong style=\"text-align: initial;font-size: 1em\"> Development of Nuclear Physics : <\/strong><span style=\"text-align: initial;font-size: 1em\">The beginning of <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> Physics is considered from 1996 when Henry Becquerel discovered radioactivity. Since then <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> physics have undergone a long journey and a number of discoveries, concepts have been developed.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\"><em>2.1 <\/em><\/strong><strong style=\"text-align: initial;font-size: 1em\">Discovery of nucleus ; Rutherford\u2019s gold-foil experiment: <\/strong><span style=\"text-align: initial;font-size: 1em\">The nucleus was discovered by Ernest Rutherford in 1911, on the basis of his famous alpha particle \u2013gold foil scattering experiment.<\/span><\/p>\r\n\r\n<\/div>\r\n<div>\r\n\r\n<img class=\"wp-image-25 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1.png\" alt=\"\" width=\"604\" height=\"493\" \/>\r\n\r\n&nbsp;\r\n<p style=\"text-align: center\">Fig. 1 : the picture of the experimental setup of Rutherford\u2019s gold foil experiment.<\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">In his famous Gold foil <\/span>experiment ,<span style=\"text-align: initial;font-size: 1em\"> Rutherford used a narrow beam of energetic alpha particles to pass through a thin gold foil, and the scattered alpha particles were recorded on a movable zinc <\/span>sulphide<span style=\"text-align: initial;font-size: 1em\"> screen after the foil. In his experiment he made the following observations:<\/span><\/p>\r\n\r\n<ol>\r\n \t<li style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">Almost all (~ 99 %) the alpha particles did pass through the foil but (scattering angle 00).<\/span><\/li>\r\n \t<li style=\"text-align: justify\">Some alpha particles were deflected off at different angles as observed on the screen of the detector. (scattering angle 00 \u2013 1800).<\/li>\r\n \t<li style=\"text-align: justify\">Very few of the alpha particles (one or two) even bounced backwards<span style=\"text-align: initial;font-size: 1em\"> after hitting the gold foil (scattering angle 1800).<\/span><\/li>\r\n<\/ol>\r\n<\/div>\r\n<div>\r\n\r\n\u00a0 \u00a0 On the basis of these observations, Rutherford made the following conclusions:\r\n<ul>\r\n \t<li style=\"text-align: justify\">Since most of the alpha particles passed straight through the gold foil without any deflection, most of the space within the atoms is empty.<\/li>\r\n \t<li style=\"text-align: justify\">Since some of the alpha particles (which are big in size) were deflected by large angles or bounced backwards<span style=\"font-size: 1em\">, they must have approached some positively charged region responsible for the deflection. This positively charged region is now <\/span><strong style=\"font-size: 1em\">called the nucleus<\/strong><span style=\"font-size: 1em\">.<\/span><\/li>\r\n \t<li style=\"text-align: justify\">Since the alpha particles are heavy charge particles and are deflected by the central volume of charge, it shows that almost all the mass of the atom must be within the central volume.<\/li>\r\n<\/ul>\r\n<p style=\"text-align: justify\"><strong>\u00a0 \u00a02.2 Composition of nucleus ; the proton-electron theory: <\/strong>At the time when nucleus was discovered by Rutherford, only two fermionic particles, proton and electron were known. So it was thought that the nucleus was composed of protons and electrons, i.e. a nucleus X with mass A and charge Z was supposed to be composed of 2-protons and 1-electron. This theory was successful in explaining most of the experimental findings of that time, including the emission of alpha, beta and gamma radiations in radioactivity. However, later on it was turned out to be limited in its approach and therefore had to be discarded due to its inability to explain the following observed facts:<\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong>a<\/strong>.<strong> According to the Heisenberg uncertainty principle<\/strong>, if electron has to be within the nucleus, then its de-Broglie wavelength had to be of the order of the size of the nucleus.(a few <em>fermi<\/em>) \u2013<\/p>\r\n\r\n<\/div>\r\n<img class=\"alignnone wp-image-26 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2.png\" alt=\"\" width=\"825\" height=\"323\" \/>\r\n<div><span style=\"text-align: initial;font-size: 1em\">\u00a0 \u00a0 So the Kinetic energy of the electron :<\/span><strong style=\"text-align: initial;font-size: 1em\">\u00a0<\/strong><\/div>\r\n<div>\r\n\r\n<img class=\"wp-image-27 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3.png\" alt=\"\" width=\"948\" height=\"116\" \/>\r\n\r\n<strong>\u00a0<\/strong>\r\n\r\n<strong>b. Due to violation of angular momentum coupling rule:<\/strong>\r\n\r\n<strong>\u00a0<\/strong>\r\n\r\n<img class=\"alignnone wp-image-28 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4.png\" alt=\"\" width=\"939\" height=\"45\" \/>\r\n\r\n<strong>\u00a0<\/strong>So there should be two protons and one electron. As proton and electron both are fermions with spin \u00bd particles.\r\n\r\n<\/div>\r\n<img class=\"alignnone wp-image-29 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5.png\" alt=\"\" width=\"949\" height=\"160\" \/>\r\n<div>\r\n\r\n<strong>\u00a0 \u00a0\u00a0<\/strong><span style=\"text-align: initial;font-size: 1em\">But the measured ground state spin of <\/span>deuteron is :<span style=\"text-align: initial;font-size: 1em\"> J = 1<\/span>\r\n\r\n<\/div>\r\n<div>\r\n\r\n<strong>\u00a0 \u00a0\u00a0<\/strong><strong>c. Magnetic moment value of the nucleus <\/strong>:\r\n\r\n<strong style=\"text-align: initial;font-size: 1em\">\u00a0<img class=\"alignnone wp-image-30 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6.png\" alt=\"\" width=\"948\" height=\"206\" \/><\/strong>\r\n\r\n<\/div>\r\n<div>\r\n<p style=\"text-align: justify\"><strong>\u00a0<\/strong><strong>\u00a0<\/strong>So, as the measured magnetic moment of nuclei are very much less than the magnetic moment of the electron, the electron cannot reside inside the nucleus.<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\"><strong>d. stability of nucleus with both proton and electron inside: <\/strong>If electron has to be within the nucleus, then a very strong force, even stronger than the electromagnetic force would be needed to bound them. Yet no evidence of any strong force between the proton and the atomic electrons exist.<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\"><strong>2.3. Discovery of neutron : <\/strong>The neutron was discovered in 1932 as the result of a series of experiments on the nuclear reactions made by physicist in different countries. The historic among them are the following :<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\"><strong>Working in Germany, W.G. Bothe and H. Becker in 1930<\/strong>, found that when samples of boron or beryllium were bombarded with alpha particles, they emitted invisible, uncharged radiations that\u00a0<span style=\"text-align: initial;font-size: 1em\">resembles the gamma rays. Its interaction with matter showed that it carried energies ~ 10 MeV (much energetic than the gamma rays previously observed.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><img class=\"wp-image-32 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7.png\" alt=\"\" width=\"964\" height=\"46\" \/><\/p>\r\n\r\n<\/div>\r\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">and showed that this radiation was able to knock protons out of paraffin. But they misinterpreted the phenomenon as <\/span>scattering<span style=\"text-align: initial;font-size: 1em\"> of gamma rays on protons (a process similar to Compton effect - <\/span>scattering<span style=\"text-align: initial;font-size: 1em\"> of -rays on electrons).<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">Chadwick in 1932 at Cambridge (U.K.) <\/strong><span style=\"text-align: initial;font-size: 1em\">studied the same reaction but used <\/span>ionisation<span style=\"text-align: initial;font-size: 1em\"> chamber to measure <\/span>ionisation<span style=\"text-align: initial;font-size: 1em\"> and the length of <\/span>track<span style=\"text-align: initial;font-size: 1em\">. He used several target materials (H, He, Li, etc.) on the way of neutral radiation from Be and observed that the particles ejected from hydrogen behaved like protons with speeds up to 3.2 109 cm\/s. He also noticed that the particles ejected from the heavier targets had larger <\/span>ionising<span style=\"text-align: initial;font-size: 1em\"> power and were in each case recoil ions of the element. On the basis of his observations, he concluded that if the ejection of a proton is due to the scattering of <\/span>photon<span style=\"text-align: initial;font-size: 1em\"> on <\/span>nucleus<span style=\"text-align: initial;font-size: 1em\">, then to speed up proton up to 3.2 109 cm\/s, a 52 MeV photon is needed. This exceeded all known energies of photons, emitted by nuclei. All difficulties disappeared when he assumed that incident particles are neutral particles with the mass equal to that of <\/span>proton<span style=\"text-align: initial;font-size: 1em\"> (which he proved mathematically too on the basis of his kinematic calculations). Chadwick called this neutral particle as neutron and published its findings in a letter to Nature Journal in 1932, on the basis of which he got the Nobel Prize in 1935.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">2.4 The proton-neutron theory of nucleus <\/strong>:<span style=\"text-align: initial;font-size: 1em\"> The discovery of <\/span>neutron<span style=\"text-align: initial;font-size: 1em\"> by Chadwick gave way to the proton-neutron model of <\/span>atomic<span style=\"text-align: initial;font-size: 1em\"> nucleus. According to this <\/span>theory<span style=\"text-align: initial;font-size: 1em\"> the nucleus of an atom having atomic number Z and mass number A consists of Z protons and A-Z neutrons. The isotopes of the nucleus differ only in the number of the neutrons they contain. Thus the nucleus of the Hydrogen (1H1) <\/span>consist<span style=\"text-align: initial;font-size: 1em\"> of one proton while that of deuteron (2D1, an isotope of hydrogen) consists of one proton and one neutron. A more general term \u2018nucleons\u2019 refers to both kinds of nuclear particles.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">3.0 Our present understanding of the nuclei <\/strong><strong style=\"text-align: initial;font-size: 1em\">:<\/strong> The nuclear<span style=\"text-align: initial;font-size: 1em\"> physics is now more than 100 years old. In this long <\/span>duration<span style=\"text-align: initial;font-size: 1em\"> it has got so much maturity that people are exploring the ways to use it rather than exploring the world of nuclei. Our current understanding of the world of nuclei suggest that there are around 6000 possible (stable\/unstable) combinations of proton &amp; neutrons (nuclei) and out of which roughly about 3000 have been discovered (or at least have been produced in the laboratories) All the known nuclei, when arranged in terms of the number of neutrons and protons in them in a chart (Segre chart) shown below, the following observation can be made. :<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">Stable nuclei : <\/strong><span style=\"text-align: initial;font-size: 1em\">The nuclei which do not decay by itself via any mode are called stable nuclei. In the Segre chart, the nuclei shown by \u2018black dot\u2019 are stable nuclei. A hypothetical line joining all the stable nuclei is called <\/span><strong style=\"text-align: initial;font-size: 1em\">\u2018line of stability\u2019<\/strong><span style=\"text-align: initial;font-size: 1em\"> or the <\/span><strong style=\"text-align: initial;font-size: 1em\">\u2018beta stability line\u2019<\/strong><span style=\"text-align: initial;font-size: 1em\"> (the unstable nuclei in the neighborhood of the stable nuclei decay preferentially by beta particle emission and attain the stable configuration).<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">Unstable nuclei : <\/strong><span style=\"text-align: initial;font-size: 1em\">The nuclei falling in the \u2018 blue region\u2019 or \u2018green region\u2019 are called unstable nuclei. Since in these nuclei, the neutron to proton ratio is more (or less) than what is required for the stability, so they decay to other nuclei via -particle (for heavy nuclei) or (and) particle (for intermediate and lighter nuclei) emission until they attain some stable structure.<\/span><\/p>\r\n\r\n<div>\r\n\r\n<img class=\"alignnone wp-image-33 size-large\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-1024x707.png\" alt=\"\" width=\"1024\" height=\"707\" \/>\r\n<p style=\"text-align: center\">Fig. 2 : The chart of nuclei (Segre Chart).<\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong>Neutron dripline <\/strong>:The number of isotopes any nucleus can have is governed by the interplay between the electromagnetic force acting between the protons and the strong nuclear forces acting between p-p, n-n &amp; n-p inside the nucleus. So the number of isotopes for a given nucleus is limited, i.e there is a limit upto which the neutrons can be added to a given nucleus. The nucleus after which no more neutron can be added to it (neutron separation energy, Sn = 0) is called the drip-line nucleus. The hypothetical line joining all the drip-line nuclei towards the neutron axis in the Segre chart is called \u2018neutron dripline\u2019.<\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong>Proton dripline: <\/strong>The number of isobars for a given mass number is limited, i.e there is a limit upto which the protons can be added to a given nucleus. The nucleus after which no more proton can be added to it (proton separation energy, Sp = 0) is called the drip-line nucleus. The hypothetical line\u00a0<span style=\"text-align: initial;font-size: 1em\">joining all the drip-line nuclei towards the proton axis in the Segre chart is called \u2018neutron dripline\u2019.<\/span><\/p>\r\n\r\n<\/div>\r\n<div>\r\n\r\n&nbsp;\r\n\r\n<strong>4.0 Useful terms in nuclear physics: <\/strong>Following terms are most commonly used in nuclear physics:\r\n\r\n<em>Nuclide <\/em>:\u00a0\u00a0\u00a0\u00a0 A nuclear species, with a given proton number <strong>Z<\/strong> and neutron number <strong>N<\/strong>\r\n\r\n&nbsp;\r\n\r\n<em>Isotopes <\/em>:\u00a0\u00a0\u00a0 Nuclides of same <strong>Z<\/strong> and different <strong>N<\/strong>\r\n\r\n&nbsp;\r\n\r\n<em>Isotones <\/em>:\u00a0\u00a0\u00a0 Nuclides of same <strong>N<\/strong> and different <strong>Z<\/strong>\r\n\r\n&nbsp;\r\n\r\n<em>Isobars <\/em><strong>:<\/strong>\u00a0\u00a0\u00a0\u00a0 Nuclides of same mass number <strong>A<\/strong> (<strong>A<\/strong> = <strong>Z<\/strong> + <strong>N<\/strong>)\r\n\r\n&nbsp;\r\n\r\n<em>Isomer <\/em>:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Nuclide in an excited state with a measurable half-life\r\n\r\n&nbsp;\r\n\r\n<em>Nucleon <\/em>:\u00a0\u00a0\u00a0 Neutron or proton\r\n\r\n&nbsp;\r\n\r\n<em>Mesons <\/em>:\u00a0\u00a0\u00a0\u00a0 Particles having mass between electron mass (m0) &amp; proton mass (MH).\r\n\r\n&nbsp;\r\n\r\n<em>Positron <\/em>:\u00a0\u00a0\u00a0 Positively charged electron of mass m0\r\n\r\n&nbsp;\r\n\r\n<em>Photon <\/em>:\u00a0\u00a0\u00a0\u00a0\u00a0 Quantum of E-M radiation, commonly apparent as light, x ray, or\u00a0\u00a0 - ray\r\n\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong>5.0 Some basic units used in nuclear physics: <\/strong>The following are the most common used units in nuclear physics<\/p>\r\n&nbsp;\r\n\r\n<strong style=\"text-align: initial;font-size: 1em\"><img class=\"wp-image-36 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9.png\" alt=\"\" width=\"959\" height=\"454\" \/><\/strong>\r\n\r\n<\/div>\r\n<ol start=\"6\">\r\n \t<li><strong>Summary:<\/strong><\/li>\r\n<\/ol>\r\n<p style=\"text-align: justify\">The world of nuclear science is very fancy. Since its inception, the nuclear physics has solved number of scientific mysteries of the Universe and has significantly contributed in understanding our World today. Now the Nuclear Physics has evolved to such a level so that focus has now a bit shifted from solving the mysteries of world to using it for improving the quality of life on earth. Nowadays the nuclear techniques are being preferentially used in various sectors of human activities, In medical sector, the nuclear techniques are used for diagnosis as well as threptic purposes. In agriculture sector, the nuclear techniques are in use for pest control, getting improved varieties of seed, enhancing the production and preserving the agriculture produce. In industries, the nuclear techniques are used for a variety of reasons like testing of products, improving the quality of products (Vulcanization, Galvanization, etc.). In archaeology, the nuclear techniques are in use for finding the age of the fossils while in geology, the technique is use in the detection and exploration of minerals remotely. Now days in almost every field, the nuclear techniques are in use either as the only choice or an alternate to other conventional techniques due to their great precession, simplicity, inexpensive and time saving nature.<\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\"><em>References:<\/em><\/strong><\/p>\r\n\r\n<div>\r\n<ol>\r\n \t<li>ntroduction to Nuclear Physics, 2nd Edition, W.N.Cottingham &amp; D.A. Greenwood.<\/li>\r\n \t<li>Concepts of Modern Physics, Arthur Beiser, McGraw-Hill Publication.<\/li>\r\n \t<li>Introduction to Nuclear and Particle Physics, A.Das &amp; T. Ferbel, World Scientific Publication.<\/li>\r\n<\/ol>\r\n<strong><em>\u00a0 \u00a0Web Links<\/em><\/strong>\r\n<ol>\r\n \t<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Nuclear_physics\">https:\/\/en.wikipedia.org\/wiki\/Nuclear_physics<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/playlist?list=PLOarn8QL6W_LOBTvWwLac5VCxJpkiHa-e\">https:\/\/www.youtube.com\/playlist?list=PLOarn8QL6W_LOBTvWwLac5VCxJpkiHa-e<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=uhRbRnei8A4\">https:\/\/www.youtube.com\/watch?v=uhRbRnei8A4<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/vimeo.com\/87848821\">https:\/\/vimeo.com\/87848821<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.sheffield.ac.uk\/polopoly_fs\/1.14291!\/file\/phy008_lecturenotes_v1.pdf\">https:\/\/www.sheffield.ac.uk\/polopoly_fs\/1.14291!\/file\/phy008_lecturenotes_v1.pdf<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/ocw.mit.edu\/courses\/nuclear-engineering\/22-02-introduction-to-applied-nuclear-physics-spring-2012\/lecture-notes\/MIT22_02S12_lec_ch1.pdf\">http:\/\/ocw.mit.edu\/courses\/nuclear-engineering\/22-02-introduction-to-applied-nuclear-physics-spring-<\/a><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/ocw.mit.edu\/courses\/nuclear-engineering\/22-02-introduction-to-applied-nuclear-physics-spring-2012\/lecture-notes\/MIT22_02S12_lec_ch1.pdf\">2012\/lecture-notes\/MIT22_02S12_lec_ch1.pdf<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/scienze-como.uninsubria.it\/phil\/Corsi\/FN\/LN-NPP.pdf\">http:\/\/scienze-como.uninsubria.it\/phil\/Corsi\/FN\/LN-NPP.pdf<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/indico.cern.ch\/event\/57571\/attachments\/989967\/1407605\/Goutte_part1.pdf\">https:\/\/indico.cern.ch\/event\/57571\/attachments\/989967\/1407605\/Goutte_part1.pdf<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8\">https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=NlDPPANJZXM\">https:\/\/www.youtube.com\/watch?v=NlDPPANJZXM<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=7KyNiuG19TE\">https:\/\/www.youtube.com\/watch?v=7KyNiuG19TE<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/study.com\/academy\/lesson\/early-atomic-theory-dalton-thompson-rutherford-and-millikan.html\">http:\/\/study.com\/academy\/lesson\/early-atomic-theory-dalton-thompson-rutherford-and-millikan.html<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=_7DAlvRI1M4\">https:\/\/www.youtube.com\/watch?v=_7DAlvRI1M4<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8\">https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=kBgIMRV895w\">https:\/\/www.youtube.com\/watch?v=kBgIMRV895w<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=AGNUJ5IKSP8\">https:\/\/www.youtube.com\/watch?v=AGNUJ5IKSP8<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=IcL917imLRY\">https:\/\/www.youtube.com\/watch?v=IcL917imLRY<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.quora.com\/What-are-some-mind-blowing-facts-about-nuclear-physics\">https:\/\/www.quora.com\/What-are-some-mind-blowing-facts-about-nuclear-physics<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.encyclopedia.com\/topic\/nuclear_physics.aspx\">http:\/\/www.encyclopedia.com\/topic\/nuclear_physics.aspx<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.scoopwhoop.com\/inothernews\/homi-bhabha-facts\/\">http:\/\/www.scoopwhoop.com\/inothernews\/homi-bhabha-facts\/<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.aip.org\/history\/exhibits\/rutherford\/sections\/alpha-particles-atom.html\">https:\/\/www.aip.org\/history\/exhibits\/rutherford\/sections\/alpha-particles-atom.html<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.funtrivia.com\/en\/SciTech\/Atomic-and-Subatomic-Physics-17329.html\">http:\/\/www.funtrivia.com\/en\/SciTech\/Atomic-and-Subatomic-Physics-17329.html<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/faculty.wcas.northwestern.edu\/~infocom\/Ideas\/nuc_timeline.html\">http:\/\/faculty.wcas.northwestern.edu\/~infocom\/Ideas\/nuc_timeline.html<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/faculty.cua.edu\/sober\/635\/Timeline.pdf\">http:\/\/faculty.cua.edu\/sober\/635\/Timeline.pdf<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/regentsprep.org\/regents\/physics\/101facts\/101facts.cfm\">http:\/\/regentsprep.org\/regents\/physics\/101facts\/101facts.cfm<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.sparknotes.com\/testprep\/books\/sat2\/physics\/chapter19section4.rhtml\">http:\/\/www.sparknotes.com\/testprep\/books\/sat2\/physics\/chapter19section4.rhtml<\/a><\/li>\r\n \t<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/facts.randomhistory.com\/nuclear-energy-facts.html\">http:\/\/facts.randomhistory.com\/nuclear-energy-facts.html.<\/a><\/li>\r\n<\/ol>\r\n<\/div>\r\n<div>\r\n\r\n<strong>\u00a0<\/strong><strong><em>Did You know?<\/em><\/strong>\r\n<p style=\"text-align: justify\">The 'Father of Nuclear Physics\u2019, Ernest Rutherford was born in New Zealand. He made a number of discoveries and inventions. Apart from his discovery of nucleus, he also discovered the concept of radioactive half-life and proved alpha and beta radiation in different elements.<\/p>\r\n<strong>\u00a0<\/strong>\r\n\r\nRutherford invented a new form of radio receiver while he was doing his research.\r\n\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\">While working with J.J. Thomson at Cambridge University, Rutherford conducted experiments which led to the discovery of electrons<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\">Rutherford experimented with uranium and explored its radioactive qualities. On the basis of his observations, he discovered alpha, beta and gamma rays and their properties. For his this discovery, he was awarded the Nobel Prize in 1908.<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\">In 1909, Rutherford conducted the Gold Foil Experiment which is one of his most famous works. On the basis of his observations in the experiment, he discover that atoms consist of positively charged nucleus, where the mass is centered.<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\">Rutherford held the world record for detecting electromagnetic waves by half a mile and during the First World War, he worked on a top secret project of solving the problems of submarine detection by sonar.<\/p>\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\">To honor Rutherford for his great contributions in Science, the element 'Rutherfordium' is named after him and also the unit of radioactivity is named as 'Rd' which stands for 'Rutherford'.<\/p>\r\n<strong>\u00a0<\/strong>\r\n\r\n<strong>Interesting facts about James Chadwick :<\/strong>\r\n\r\n<strong>\u00a0<\/strong>\r\n<p style=\"text-align: justify\">Chadwick\u2019s early research, was concerned with gamma-ray absorption; first with its use as a precision test of radium standards and then with applications of the method devised for standardization. He investigated the excitation of gamma rays by beta rays (electrons) and then by alpha rays (helium nuclei). In both cases the excitation was confirmed. In Berlin with Geiger, Chadwick set out to determine by direct observation,\u00a0<span style=\"text-align: initial;font-size: 1em\">using a primitive Geiger point counter, the relative intensities of the discrete lines observed by Rutherford and Robinson in radioactive <\/span>beta ray<span style=\"text-align: initial;font-size: 1em\"> spectra. Although he was able to identify a few of the most intense of the observed lines, he also found a continuous spectrum alongside the discrete one. He tried changing the detection apparatus, but this merely confirmed the conclusion. The result came as a complete surprise and could not readily be explained theoretically, but it was a clear indication of Chadwick\u2019s experimental skill. Both spectra, and the relation between <\/span>them,<span style=\"text-align: initial;font-size: 1em\"> became an important problem in atomic and nuclear physics.<\/span><\/p>\r\n&nbsp;\r\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">Chadwick\u2019s last major work before leaving Cambridge was to demonstrate the nuclear photoelectric effect in the form of the disintegration of deuterium under <\/span>gamma ray<span style=\"text-align: initial;font-size: 1em\"> illumination. This work also led to the first accurate figure of the mass of the neutron, and to speculation as to the significance of slow neutrons. It was not published, however, and a few months later Enrico Fermi observed and realized the significance of the same phenomenon.<\/span><\/p>\r\n\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td><strong>you can view video on Introduction to Nuclear Physics<\/strong><\/td>\r\n<td><a href=\"https:\/\/youtu.be\/9cyDFNPPOYU\" target=\"_blank\" rel=\"noopener\"><img class=\"alignnone wp-image-120\" src=\"http:\/\/epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/2018\/11\/download.png\" alt=\"\" width=\"36\" height=\"36\" \/><\/a><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\"><em>Biography:<\/em><\/strong><\/p>\r\n\r\n<ol>\r\n \t<li style=\"text-align: justify\"><a style=\"font-size: 1em\" href=\"http:\/\/www.biography.com\/people\/ernest-rutherford-39099\">http:\/\/www.biography.com\/people\/ernest-rutherford-39099<\/a><\/li>\r\n \t<li style=\"text-align: justify\"><a href=\"http:\/\/www.nobelprize.org\/nobel_prizes\/physics\/laureates\/1935\/chadwick-bio.html\">http:\/\/www.nobelprize.org\/nobel_prizes\/physics\/laureates\/1935\/chadwick-bio.html<\/a><\/li>\r\n \t<li style=\"text-align: justify\"><a href=\"http:\/\/www.britannica.com\/biography\/Werner-Heisenberg\">http:\/\/www.britannica.com\/biography\/Werner-Heisenberg<\/a><\/li>\r\n \t<li style=\"text-align: justify\"><a href=\"http:\/\/www.famousscientists.org\/marie-curie\/\">http:\/\/www.famousscientists.org\/marie-curie\/<\/a><\/li>\r\n \t<li style=\"text-align: justify\"><a href=\"http:\/\/www.famousscientists.org\/j-j-thomson\/\">http:\/\/www.famousscientists.org\/j-j-thomson\/<\/a><\/li>\r\n<\/ol>\r\n<\/div>\r\n&nbsp;\r\n\r\n&nbsp;","rendered":"<div><span style=\"float: right\"><a href=\"https:\/\/youtu.be\/9cyDFNPPOYU\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" src=\"http:\/\/epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/2018\/11\/download.png\" alt=\"epgp books\" width=\"75px\" height=\"75px;\" \/><\/a><br \/>\n<\/span><\/div>\n<div>\n<p><strong>\u00a0 \u00a0 Learning Outcomes<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p>From this module students may get to know about the following:<\/p>\n<ul>\n<li>The aim and scope of nuclear physics.<\/li>\n<li>The development of nuclear physics.<\/li>\n<li>Present understanding of nuclear physics.<\/li>\n<li>Useful terms and basic units of measurements used in nuclear physics<\/li>\n<\/ul>\n<p><strong style=\"text-align: initial;font-size: 1em\">\u00a0 \u00a0 1. Aim and scope of nuclear physics<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">The nuclear physics is the branch of physics in which the study of <\/span>atomic<span style=\"text-align: initial;font-size: 1em\"> nucleus, its constituents and the interactions happening among them is done. Right from the discovery of radioactivity in 1996 by Henri Becquerel, <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> physics has evolved with time and now its applications can be seen in many fields. The most common application of nuclear physics is in power generation, but its use in many other fields like medical sector, agriculture sector, archaeology, industries <\/span>and<span style=\"text-align: initial;font-size: 1em\"> geology has now made the study of nuclear physics important. Though the aims and objectives of studying nuclear physics are not limited to <\/span>few<span style=\"text-align: initial;font-size: 1em\"> domains, <\/span>but<span style=\"text-align: initial;font-size: 1em\"> the importance of learning nuclear physics can be understood in the following ways :<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">1.1 Understanding the origin of elements: <\/strong><span style=\"text-align: initial;font-size: 1em\">The knowledge of nuclear physics, helps us in understanding the origin of our world and the elements in it. Our Universe is believed to be formed in the \u2018Big Bang\u2019 happened some 14 billion years ago. In the early <\/span>Universe<span style=\"text-align: initial;font-size: 1em\"> only the light elements like hydrogen and helium along with trace amounts of lithium and beryllium were formed. Then as the cloud of cosmic dust and gases from the Big Bang cooled, stars formed, which then grouped together to form galaxies. The other elements heavier than the hydrogen and helium found in nature were created in nuclear reactions in these stars and in huge stellar explosions known as supernovae. Few examples are :<\/span><\/p>\n<\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-24 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled.png\" alt=\"\" width=\"839\" height=\"172\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled.png 839w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-300x62.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-768x157.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-65x13.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-225x46.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-350x72.png 350w\" sizes=\"auto, (max-width: 839px) 100vw, 839px\" \/><\/p>\n<div>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong>1.2\u00a0\u00a0 Understanding the origin of various properties of elements <\/strong>: The nuclear physics not only accounts for the formation of elements in the universe, it also explains as how the elements gain various properties like mass, charge spins etc. To our basic understanding, the nucleus consists of protons and neutrons. The protons are positively charged while the neutrons are neutral. So the charge on the nucleus is just the algebraic sum of the charge on the protons inside it. Also as the proton and neutron are massive particles (mp ~ mn), so almost all the mass of elements in the universe is due to mass of the nuclei. The proton and neutron are fermionic particles with spin 1\/2, so all the nuclei have spins. The arrangement of protons and neutrons inside the nucleus is governed by the strong interaction acting between them inside the nucleus. So depending upon the number of protons and neutrons and their distribution inside, the nuclei have different shapes and sizes. So nuclear physics in general can account for almost all the observed properties of elements in the universe.<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong>1.3 Understanding the origin the forces in Universe<\/strong>: The four basic forces in the Universe are the strong force, electromagnetic force, weak force and the gravitational forces. These forces vary in\u00a0<span style=\"text-align: initial;font-size: 1em\">strength and their range of applications. The modern days understanding of nuclear and particle physics suggest that all these four forces at the fundamental level work through some mediating particle. The strong forces work via exchange of \u2018gluons\u2019, The weak force via \u2018W\/ G bosons, electromagnetic force via \u2018photons\u2019 and the gravitational force via \u2018graviton\u2019. Working at the fundamental level, the scientists have found that all these four forces are not different but have a single origin. Through Grand Unified Theory (GUT) they have been able to unify the strong force, electromagnetic forces <\/span>and<span style=\"text-align: initial;font-size: 1em\"> the weak forces successively.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">1.4 Improving the quality of life on earth <\/strong>:<span style=\"text-align: initial;font-size: 1em\"> The nuclear physics is not only unfolding the mysteries of the University but is helping to improve the quality of life on earth. Nowadays the nuclear techniques are being used by almost every industry. The biggest example of nuclear application is in power generation in <\/span>Nuclear<span style=\"text-align: initial;font-size: 1em\"> Power plant. The other big area using <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> techniques is the medical sector, where a number of sophisticated diagnostic and therapeutic procedures based on <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> techniques have been developed.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">2<\/strong><span style=\"text-align: initial;font-size: 1em\">.<\/span><strong style=\"text-align: initial;font-size: 1em\"> Development of Nuclear Physics : <\/strong><span style=\"text-align: initial;font-size: 1em\">The beginning of <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> Physics is considered from 1996 when Henry Becquerel discovered radioactivity. Since then <\/span>the nuclear<span style=\"text-align: initial;font-size: 1em\"> physics have undergone a long journey and a number of discoveries, concepts have been developed.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\"><em>2.1 <\/em><\/strong><strong style=\"text-align: initial;font-size: 1em\">Discovery of nucleus ; Rutherford\u2019s gold-foil experiment: <\/strong><span style=\"text-align: initial;font-size: 1em\">The nucleus was discovered by Ernest Rutherford in 1911, on the basis of his famous alpha particle \u2013gold foil scattering experiment.<\/span><\/p>\n<\/div>\n<div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-25 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1.png\" alt=\"\" width=\"604\" height=\"493\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1.png 604w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1-300x245.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1-65x53.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1-225x184.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-1-350x286.png 350w\" sizes=\"auto, (max-width: 604px) 100vw, 604px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center\">Fig. 1 : the picture of the experimental setup of Rutherford\u2019s gold foil experiment.<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">In his famous Gold foil <\/span>experiment ,<span style=\"text-align: initial;font-size: 1em\"> Rutherford used a narrow beam of energetic alpha particles to pass through a thin gold foil, and the scattered alpha particles were recorded on a movable zinc <\/span>sulphide<span style=\"text-align: initial;font-size: 1em\"> screen after the foil. In his experiment he made the following observations:<\/span><\/p>\n<ol>\n<li style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">Almost all (~ 99 %) the alpha particles did pass through the foil but (scattering angle 00).<\/span><\/li>\n<li style=\"text-align: justify\">Some alpha particles were deflected off at different angles as observed on the screen of the detector. (scattering angle 00 \u2013 1800).<\/li>\n<li style=\"text-align: justify\">Very few of the alpha particles (one or two) even bounced backwards<span style=\"text-align: initial;font-size: 1em\"> after hitting the gold foil (scattering angle 1800).<\/span><\/li>\n<\/ol>\n<\/div>\n<div>\n<p>\u00a0 \u00a0 On the basis of these observations, Rutherford made the following conclusions:<\/p>\n<ul>\n<li style=\"text-align: justify\">Since most of the alpha particles passed straight through the gold foil without any deflection, most of the space within the atoms is empty.<\/li>\n<li style=\"text-align: justify\">Since some of the alpha particles (which are big in size) were deflected by large angles or bounced backwards<span style=\"font-size: 1em\">, they must have approached some positively charged region responsible for the deflection. This positively charged region is now <\/span><strong style=\"font-size: 1em\">called the nucleus<\/strong><span style=\"font-size: 1em\">.<\/span><\/li>\n<li style=\"text-align: justify\">Since the alpha particles are heavy charge particles and are deflected by the central volume of charge, it shows that almost all the mass of the atom must be within the central volume.<\/li>\n<\/ul>\n<p style=\"text-align: justify\"><strong>\u00a0 \u00a02.2 Composition of nucleus ; the proton-electron theory: <\/strong>At the time when nucleus was discovered by Rutherford, only two fermionic particles, proton and electron were known. So it was thought that the nucleus was composed of protons and electrons, i.e. a nucleus X with mass A and charge Z was supposed to be composed of 2-protons and 1-electron. This theory was successful in explaining most of the experimental findings of that time, including the emission of alpha, beta and gamma radiations in radioactivity. However, later on it was turned out to be limited in its approach and therefore had to be discarded due to its inability to explain the following observed facts:<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong>a<\/strong>.<strong> According to the Heisenberg uncertainty principle<\/strong>, if electron has to be within the nucleus, then its de-Broglie wavelength had to be of the order of the size of the nucleus.(a few <em>fermi<\/em>) \u2013<\/p>\n<\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-26 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2.png\" alt=\"\" width=\"825\" height=\"323\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2.png 825w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2-300x117.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2-768x301.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2-65x25.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2-225x88.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-2-350x137.png 350w\" sizes=\"auto, (max-width: 825px) 100vw, 825px\" \/><\/p>\n<div><span style=\"text-align: initial;font-size: 1em\">\u00a0 \u00a0 So the Kinetic energy of the electron :<\/span><strong style=\"text-align: initial;font-size: 1em\">\u00a0<\/strong><\/div>\n<div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-27 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3.png\" alt=\"\" width=\"948\" height=\"116\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3.png 948w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3-300x37.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3-768x94.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3-65x8.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3-225x28.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-3-350x43.png 350w\" sizes=\"auto, (max-width: 948px) 100vw, 948px\" \/><\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p><strong>b. Due to violation of angular momentum coupling rule:<\/strong><\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-28 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4.png\" alt=\"\" width=\"939\" height=\"45\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4.png 939w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4-300x14.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4-768x37.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4-65x3.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4-225x11.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-4-350x17.png 350w\" sizes=\"auto, (max-width: 939px) 100vw, 939px\" \/><\/p>\n<p><strong>\u00a0<\/strong>So there should be two protons and one electron. As proton and electron both are fermions with spin \u00bd particles.<\/p>\n<\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-29 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5.png\" alt=\"\" width=\"949\" height=\"160\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5.png 949w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5-300x51.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5-768x129.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5-65x11.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5-225x38.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-5-350x59.png 350w\" sizes=\"auto, (max-width: 949px) 100vw, 949px\" \/><\/p>\n<div>\n<p><strong>\u00a0 \u00a0\u00a0<\/strong><span style=\"text-align: initial;font-size: 1em\">But the measured ground state spin of <\/span>deuteron is :<span style=\"text-align: initial;font-size: 1em\"> J = 1<\/span><\/p>\n<\/div>\n<div>\n<p><strong>\u00a0 \u00a0\u00a0<\/strong><strong>c. Magnetic moment value of the nucleus <\/strong>:<\/p>\n<p><strong style=\"text-align: initial;font-size: 1em\">\u00a0<img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-30 size-full\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6.png\" alt=\"\" width=\"948\" height=\"206\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6.png 948w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6-300x65.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6-768x167.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6-65x14.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6-225x49.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-6-350x76.png 350w\" sizes=\"auto, (max-width: 948px) 100vw, 948px\" \/><\/strong><\/p>\n<\/div>\n<div>\n<p style=\"text-align: justify\"><strong>\u00a0<\/strong><strong>\u00a0<\/strong>So, as the measured magnetic moment of nuclei are very much less than the magnetic moment of the electron, the electron cannot reside inside the nucleus.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\"><strong>d. stability of nucleus with both proton and electron inside: <\/strong>If electron has to be within the nucleus, then a very strong force, even stronger than the electromagnetic force would be needed to bound them. Yet no evidence of any strong force between the proton and the atomic electrons exist.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\"><strong>2.3. Discovery of neutron : <\/strong>The neutron was discovered in 1932 as the result of a series of experiments on the nuclear reactions made by physicist in different countries. The historic among them are the following :<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\"><strong>Working in Germany, W.G. Bothe and H. Becker in 1930<\/strong>, found that when samples of boron or beryllium were bombarded with alpha particles, they emitted invisible, uncharged radiations that\u00a0<span style=\"text-align: initial;font-size: 1em\">resembles the gamma rays. Its interaction with matter showed that it carried energies ~ 10 MeV (much energetic than the gamma rays previously observed.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-32 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7.png\" alt=\"\" width=\"964\" height=\"46\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7.png 964w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7-300x14.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7-768x37.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7-65x3.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7-225x11.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-7-350x17.png 350w\" sizes=\"auto, (max-width: 964px) 100vw, 964px\" \/><\/p>\n<\/div>\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">and showed that this radiation was able to knock protons out of paraffin. But they misinterpreted the phenomenon as <\/span>scattering<span style=\"text-align: initial;font-size: 1em\"> of gamma rays on protons (a process similar to Compton effect &#8211; <\/span>scattering<span style=\"text-align: initial;font-size: 1em\"> of -rays on electrons).<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">Chadwick in 1932 at Cambridge (U.K.) <\/strong><span style=\"text-align: initial;font-size: 1em\">studied the same reaction but used <\/span>ionisation<span style=\"text-align: initial;font-size: 1em\"> chamber to measure <\/span>ionisation<span style=\"text-align: initial;font-size: 1em\"> and the length of <\/span>track<span style=\"text-align: initial;font-size: 1em\">. He used several target materials (H, He, Li, etc.) on the way of neutral radiation from Be and observed that the particles ejected from hydrogen behaved like protons with speeds up to 3.2 109 cm\/s. He also noticed that the particles ejected from the heavier targets had larger <\/span>ionising<span style=\"text-align: initial;font-size: 1em\"> power and were in each case recoil ions of the element. On the basis of his observations, he concluded that if the ejection of a proton is due to the scattering of <\/span>photon<span style=\"text-align: initial;font-size: 1em\"> on <\/span>nucleus<span style=\"text-align: initial;font-size: 1em\">, then to speed up proton up to 3.2 109 cm\/s, a 52 MeV photon is needed. This exceeded all known energies of photons, emitted by nuclei. All difficulties disappeared when he assumed that incident particles are neutral particles with the mass equal to that of <\/span>proton<span style=\"text-align: initial;font-size: 1em\"> (which he proved mathematically too on the basis of his kinematic calculations). Chadwick called this neutral particle as neutron and published its findings in a letter to Nature Journal in 1932, on the basis of which he got the Nobel Prize in 1935.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">2.4 The proton-neutron theory of nucleus <\/strong>:<span style=\"text-align: initial;font-size: 1em\"> The discovery of <\/span>neutron<span style=\"text-align: initial;font-size: 1em\"> by Chadwick gave way to the proton-neutron model of <\/span>atomic<span style=\"text-align: initial;font-size: 1em\"> nucleus. According to this <\/span>theory<span style=\"text-align: initial;font-size: 1em\"> the nucleus of an atom having atomic number Z and mass number A consists of Z protons and A-Z neutrons. The isotopes of the nucleus differ only in the number of the neutrons they contain. Thus the nucleus of the Hydrogen (1H1) <\/span>consist<span style=\"text-align: initial;font-size: 1em\"> of one proton while that of deuteron (2D1, an isotope of hydrogen) consists of one proton and one neutron. A more general term \u2018nucleons\u2019 refers to both kinds of nuclear particles.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">3.0 Our present understanding of the nuclei <\/strong><strong style=\"text-align: initial;font-size: 1em\">:<\/strong> The nuclear<span style=\"text-align: initial;font-size: 1em\"> physics is now more than 100 years old. In this long <\/span>duration<span style=\"text-align: initial;font-size: 1em\"> it has got so much maturity that people are exploring the ways to use it rather than exploring the world of nuclei. Our current understanding of the world of nuclei suggest that there are around 6000 possible (stable\/unstable) combinations of proton &amp; neutrons (nuclei) and out of which roughly about 3000 have been discovered (or at least have been produced in the laboratories) All the known nuclei, when arranged in terms of the number of neutrons and protons in them in a chart (Segre chart) shown below, the following observation can be made. :<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">Stable nuclei : <\/strong><span style=\"text-align: initial;font-size: 1em\">The nuclei which do not decay by itself via any mode are called stable nuclei. In the Segre chart, the nuclei shown by \u2018black dot\u2019 are stable nuclei. A hypothetical line joining all the stable nuclei is called <\/span><strong style=\"text-align: initial;font-size: 1em\">\u2018line of stability\u2019<\/strong><span style=\"text-align: initial;font-size: 1em\"> or the <\/span><strong style=\"text-align: initial;font-size: 1em\">\u2018beta stability line\u2019<\/strong><span style=\"text-align: initial;font-size: 1em\"> (the unstable nuclei in the neighborhood of the stable nuclei decay preferentially by beta particle emission and attain the stable configuration).<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\">Unstable nuclei : <\/strong><span style=\"text-align: initial;font-size: 1em\">The nuclei falling in the \u2018 blue region\u2019 or \u2018green region\u2019 are called unstable nuclei. Since in these nuclei, the neutron to proton ratio is more (or less) than what is required for the stability, so they decay to other nuclei via -particle (for heavy nuclei) or (and) particle (for intermediate and lighter nuclei) emission until they attain some stable structure.<\/span><\/p>\n<div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-33 size-large\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-1024x707.png\" alt=\"\" width=\"1024\" height=\"707\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-1024x707.png 1024w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-300x207.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-768x530.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-65x45.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-225x155.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8-350x242.png 350w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-8.png 1057w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p style=\"text-align: center\">Fig. 2 : The chart of nuclei (Segre Chart).<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong>Neutron dripline <\/strong>:The number of isotopes any nucleus can have is governed by the interplay between the electromagnetic force acting between the protons and the strong nuclear forces acting between p-p, n-n &amp; n-p inside the nucleus. So the number of isotopes for a given nucleus is limited, i.e there is a limit upto which the neutrons can be added to a given nucleus. The nucleus after which no more neutron can be added to it (neutron separation energy, Sn = 0) is called the drip-line nucleus. The hypothetical line joining all the drip-line nuclei towards the neutron axis in the Segre chart is called \u2018neutron dripline\u2019.<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong>Proton dripline: <\/strong>The number of isobars for a given mass number is limited, i.e there is a limit upto which the protons can be added to a given nucleus. The nucleus after which no more proton can be added to it (proton separation energy, Sp = 0) is called the drip-line nucleus. The hypothetical line\u00a0<span style=\"text-align: initial;font-size: 1em\">joining all the drip-line nuclei towards the proton axis in the Segre chart is called \u2018neutron dripline\u2019.<\/span><\/p>\n<\/div>\n<div>\n<p>&nbsp;<\/p>\n<p><strong>4.0 Useful terms in nuclear physics: <\/strong>Following terms are most commonly used in nuclear physics:<\/p>\n<p><em>Nuclide <\/em>:\u00a0\u00a0\u00a0\u00a0 A nuclear species, with a given proton number <strong>Z<\/strong> and neutron number <strong>N<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p><em>Isotopes <\/em>:\u00a0\u00a0\u00a0 Nuclides of same <strong>Z<\/strong> and different <strong>N<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p><em>Isotones <\/em>:\u00a0\u00a0\u00a0 Nuclides of same <strong>N<\/strong> and different <strong>Z<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p><em>Isobars <\/em><strong>:<\/strong>\u00a0\u00a0\u00a0\u00a0 Nuclides of same mass number <strong>A<\/strong> (<strong>A<\/strong> = <strong>Z<\/strong> + <strong>N<\/strong>)<\/p>\n<p>&nbsp;<\/p>\n<p><em>Isomer <\/em>:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Nuclide in an excited state with a measurable half-life<\/p>\n<p>&nbsp;<\/p>\n<p><em>Nucleon <\/em>:\u00a0\u00a0\u00a0 Neutron or proton<\/p>\n<p>&nbsp;<\/p>\n<p><em>Mesons <\/em>:\u00a0\u00a0\u00a0\u00a0 Particles having mass between electron mass (m0) &amp; proton mass (MH).<\/p>\n<p>&nbsp;<\/p>\n<p><em>Positron <\/em>:\u00a0\u00a0\u00a0 Positively charged electron of mass m0<\/p>\n<p>&nbsp;<\/p>\n<p><em>Photon <\/em>:\u00a0\u00a0\u00a0\u00a0\u00a0 Quantum of E-M radiation, commonly apparent as light, x ray, or\u00a0\u00a0 &#8211; ray<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong>5.0 Some basic units used in nuclear physics: <\/strong>The following are the most common used units in nuclear physics<\/p>\n<p>&nbsp;<\/p>\n<p><strong style=\"text-align: initial;font-size: 1em\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-36 size-full aligncenter\" src=\"http:\/\/phyp04.epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9.png\" alt=\"\" width=\"959\" height=\"454\" srcset=\"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9.png 959w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9-300x142.png 300w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9-768x364.png 768w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9-65x31.png 65w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9-225x107.png 225w, https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-content\/uploads\/sites\/86\/2018\/11\/Untitled-9-350x166.png 350w\" sizes=\"auto, (max-width: 959px) 100vw, 959px\" \/><\/strong><\/p>\n<\/div>\n<ol start=\"6\">\n<li><strong>Summary:<\/strong><\/li>\n<\/ol>\n<p style=\"text-align: justify\">The world of nuclear science is very fancy. Since its inception, the nuclear physics has solved number of scientific mysteries of the Universe and has significantly contributed in understanding our World today. Now the Nuclear Physics has evolved to such a level so that focus has now a bit shifted from solving the mysteries of world to using it for improving the quality of life on earth. Nowadays the nuclear techniques are being preferentially used in various sectors of human activities, In medical sector, the nuclear techniques are used for diagnosis as well as threptic purposes. In agriculture sector, the nuclear techniques are in use for pest control, getting improved varieties of seed, enhancing the production and preserving the agriculture produce. In industries, the nuclear techniques are used for a variety of reasons like testing of products, improving the quality of products (Vulcanization, Galvanization, etc.). In archaeology, the nuclear techniques are in use for finding the age of the fossils while in geology, the technique is use in the detection and exploration of minerals remotely. Now days in almost every field, the nuclear techniques are in use either as the only choice or an alternate to other conventional techniques due to their great precession, simplicity, inexpensive and time saving nature.<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\"><em>References:<\/em><\/strong><\/p>\n<div>\n<ol>\n<li>ntroduction to Nuclear Physics, 2nd Edition, W.N.Cottingham &amp; D.A. Greenwood.<\/li>\n<li>Concepts of Modern Physics, Arthur Beiser, McGraw-Hill Publication.<\/li>\n<li>Introduction to Nuclear and Particle Physics, A.Das &amp; T. Ferbel, World Scientific Publication.<\/li>\n<\/ol>\n<p><strong><em>\u00a0 \u00a0Web Links<\/em><\/strong><\/p>\n<ol>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Nuclear_physics\">https:\/\/en.wikipedia.org\/wiki\/Nuclear_physics<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/playlist?list=PLOarn8QL6W_LOBTvWwLac5VCxJpkiHa-e\">https:\/\/www.youtube.com\/playlist?list=PLOarn8QL6W_LOBTvWwLac5VCxJpkiHa-e<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=uhRbRnei8A4\">https:\/\/www.youtube.com\/watch?v=uhRbRnei8A4<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/vimeo.com\/87848821\">https:\/\/vimeo.com\/87848821<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.sheffield.ac.uk\/polopoly_fs\/1.14291!\/file\/phy008_lecturenotes_v1.pdf\">https:\/\/www.sheffield.ac.uk\/polopoly_fs\/1.14291!\/file\/phy008_lecturenotes_v1.pdf<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/ocw.mit.edu\/courses\/nuclear-engineering\/22-02-introduction-to-applied-nuclear-physics-spring-2012\/lecture-notes\/MIT22_02S12_lec_ch1.pdf\">http:\/\/ocw.mit.edu\/courses\/nuclear-engineering\/22-02-introduction-to-applied-nuclear-physics-spring-<\/a><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/ocw.mit.edu\/courses\/nuclear-engineering\/22-02-introduction-to-applied-nuclear-physics-spring-2012\/lecture-notes\/MIT22_02S12_lec_ch1.pdf\">2012\/lecture-notes\/MIT22_02S12_lec_ch1.pdf<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/scienze-como.uninsubria.it\/phil\/Corsi\/FN\/LN-NPP.pdf\">http:\/\/scienze-como.uninsubria.it\/phil\/Corsi\/FN\/LN-NPP.pdf<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/indico.cern.ch\/event\/57571\/attachments\/989967\/1407605\/Goutte_part1.pdf\">https:\/\/indico.cern.ch\/event\/57571\/attachments\/989967\/1407605\/Goutte_part1.pdf<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8\">https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=NlDPPANJZXM\">https:\/\/www.youtube.com\/watch?v=NlDPPANJZXM<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=7KyNiuG19TE\">https:\/\/www.youtube.com\/watch?v=7KyNiuG19TE<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/study.com\/academy\/lesson\/early-atomic-theory-dalton-thompson-rutherford-and-millikan.html\">http:\/\/study.com\/academy\/lesson\/early-atomic-theory-dalton-thompson-rutherford-and-millikan.html<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=_7DAlvRI1M4\">https:\/\/www.youtube.com\/watch?v=_7DAlvRI1M4<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8\">https:\/\/www.youtube.com\/watch?v=wzALbzTdnc8<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=kBgIMRV895w\">https:\/\/www.youtube.com\/watch?v=kBgIMRV895w<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=AGNUJ5IKSP8\">https:\/\/www.youtube.com\/watch?v=AGNUJ5IKSP8<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.youtube.com\/watch?v=IcL917imLRY\">https:\/\/www.youtube.com\/watch?v=IcL917imLRY<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.quora.com\/What-are-some-mind-blowing-facts-about-nuclear-physics\">https:\/\/www.quora.com\/What-are-some-mind-blowing-facts-about-nuclear-physics<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.encyclopedia.com\/topic\/nuclear_physics.aspx\">http:\/\/www.encyclopedia.com\/topic\/nuclear_physics.aspx<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.scoopwhoop.com\/inothernews\/homi-bhabha-facts\/\">http:\/\/www.scoopwhoop.com\/inothernews\/homi-bhabha-facts\/<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/www.aip.org\/history\/exhibits\/rutherford\/sections\/alpha-particles-atom.html\">https:\/\/www.aip.org\/history\/exhibits\/rutherford\/sections\/alpha-particles-atom.html<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.funtrivia.com\/en\/SciTech\/Atomic-and-Subatomic-Physics-17329.html\">http:\/\/www.funtrivia.com\/en\/SciTech\/Atomic-and-Subatomic-Physics-17329.html<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/faculty.wcas.northwestern.edu\/~infocom\/Ideas\/nuc_timeline.html\">http:\/\/faculty.wcas.northwestern.edu\/~infocom\/Ideas\/nuc_timeline.html<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/faculty.cua.edu\/sober\/635\/Timeline.pdf\">http:\/\/faculty.cua.edu\/sober\/635\/Timeline.pdf<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/regentsprep.org\/regents\/physics\/101facts\/101facts.cfm\">http:\/\/regentsprep.org\/regents\/physics\/101facts\/101facts.cfm<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/www.sparknotes.com\/testprep\/books\/sat2\/physics\/chapter19section4.rhtml\">http:\/\/www.sparknotes.com\/testprep\/books\/sat2\/physics\/chapter19section4.rhtml<\/a><\/li>\n<li><a style=\"text-align: initial;font-size: 1em\" href=\"http:\/\/facts.randomhistory.com\/nuclear-energy-facts.html\">http:\/\/facts.randomhistory.com\/nuclear-energy-facts.html.<\/a><\/li>\n<\/ol>\n<\/div>\n<div>\n<p><strong>\u00a0<\/strong><strong><em>Did You know?<\/em><\/strong><\/p>\n<p style=\"text-align: justify\">The &#8216;Father of Nuclear Physics\u2019, Ernest Rutherford was born in New Zealand. He made a number of discoveries and inventions. Apart from his discovery of nucleus, he also discovered the concept of radioactive half-life and proved alpha and beta radiation in different elements.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p>Rutherford invented a new form of radio receiver while he was doing his research.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\">While working with J.J. Thomson at Cambridge University, Rutherford conducted experiments which led to the discovery of electrons<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\">Rutherford experimented with uranium and explored its radioactive qualities. On the basis of his observations, he discovered alpha, beta and gamma rays and their properties. For his this discovery, he was awarded the Nobel Prize in 1908.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\">In 1909, Rutherford conducted the Gold Foil Experiment which is one of his most famous works. On the basis of his observations in the experiment, he discover that atoms consist of positively charged nucleus, where the mass is centered.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\">Rutherford held the world record for detecting electromagnetic waves by half a mile and during the First World War, he worked on a top secret project of solving the problems of submarine detection by sonar.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\">To honor Rutherford for his great contributions in Science, the element &#8216;Rutherfordium&#8217; is named after him and also the unit of radioactivity is named as &#8216;Rd&#8217; which stands for &#8216;Rutherford&#8217;.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p><strong>Interesting facts about James Chadwick :<\/strong><\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p style=\"text-align: justify\">Chadwick\u2019s early research, was concerned with gamma-ray absorption; first with its use as a precision test of radium standards and then with applications of the method devised for standardization. He investigated the excitation of gamma rays by beta rays (electrons) and then by alpha rays (helium nuclei). In both cases the excitation was confirmed. In Berlin with Geiger, Chadwick set out to determine by direct observation,\u00a0<span style=\"text-align: initial;font-size: 1em\">using a primitive Geiger point counter, the relative intensities of the discrete lines observed by Rutherford and Robinson in radioactive <\/span>beta ray<span style=\"text-align: initial;font-size: 1em\"> spectra. Although he was able to identify a few of the most intense of the observed lines, he also found a continuous spectrum alongside the discrete one. He tried changing the detection apparatus, but this merely confirmed the conclusion. The result came as a complete surprise and could not readily be explained theoretically, but it was a clear indication of Chadwick\u2019s experimental skill. Both spectra, and the relation between <\/span>them,<span style=\"text-align: initial;font-size: 1em\"> became an important problem in atomic and nuclear physics.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: justify\"><span style=\"text-align: initial;font-size: 1em\">Chadwick\u2019s last major work before leaving Cambridge was to demonstrate the nuclear photoelectric effect in the form of the disintegration of deuterium under <\/span>gamma ray<span style=\"text-align: initial;font-size: 1em\"> illumination. This work also led to the first accurate figure of the mass of the neutron, and to speculation as to the significance of slow neutrons. It was not published, however, and a few months later Enrico Fermi observed and realized the significance of the same phenomenon.<\/span><\/p>\n<table>\n<tbody>\n<tr>\n<td><strong>you can view video on Introduction to Nuclear Physics<\/strong><\/td>\n<td><a href=\"https:\/\/youtu.be\/9cyDFNPPOYU\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-120\" src=\"http:\/\/epgpbooks.inflibnet.ac.in\/wp-content\/uploads\/2018\/11\/download.png\" alt=\"\" width=\"36\" height=\"36\" \/><\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"text-align: justify\"><strong style=\"text-align: initial;font-size: 1em\"><em>Biography:<\/em><\/strong><\/p>\n<ol>\n<li style=\"text-align: justify\"><a style=\"font-size: 1em\" href=\"http:\/\/www.biography.com\/people\/ernest-rutherford-39099\">http:\/\/www.biography.com\/people\/ernest-rutherford-39099<\/a><\/li>\n<li style=\"text-align: justify\"><a href=\"http:\/\/www.nobelprize.org\/nobel_prizes\/physics\/laureates\/1935\/chadwick-bio.html\">http:\/\/www.nobelprize.org\/nobel_prizes\/physics\/laureates\/1935\/chadwick-bio.html<\/a><\/li>\n<li style=\"text-align: justify\"><a href=\"http:\/\/www.britannica.com\/biography\/Werner-Heisenberg\">http:\/\/www.britannica.com\/biography\/Werner-Heisenberg<\/a><\/li>\n<li style=\"text-align: justify\"><a href=\"http:\/\/www.famousscientists.org\/marie-curie\/\">http:\/\/www.famousscientists.org\/marie-curie\/<\/a><\/li>\n<li style=\"text-align: justify\"><a href=\"http:\/\/www.famousscientists.org\/j-j-thomson\/\">http:\/\/www.famousscientists.org\/j-j-thomson\/<\/a><\/li>\n<\/ol>\n<\/div>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"author":3,"menu_order":1,"template":"","meta":{"_acf_changed":false,"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["dr-sanjay-kumar-chamoli"],"pb_section_license":""},"chapter-type":[],"contributor":[58],"license":[],"class_list":["post-20","chapter","type-chapter","status-publish","hentry","contributor-dr-sanjay-kumar-chamoli"],"part":3,"_links":{"self":[{"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/chapters\/20","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/wp\/v2\/users\/3"}],"version-history":[{"count":9,"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/chapters\/20\/revisions"}],"predecessor-version":[{"id":335,"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/chapters\/20\/revisions\/335"}],"part":[{"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/chapters\/20\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/wp\/v2\/media?parent=20"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/pressbooks\/v2\/chapter-type?post=20"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/wp\/v2\/contributor?post=20"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/ebooks.inflibnet.ac.in\/phyp04\/wp-json\/wp\/v2\/license?post=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}