Chapter 31: Nuclear Applications
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Glossary Physics (I-Introduction)
1 Glossary Physics (I-introduction) - Efficiency: The percent of the work put into a machine that is converted into useful work output; = work done / energy used [-]. = eta In machines: The work output of any machine cannot exceed the work input (<=100%); in an ideal machine, where no energy is transformed into heat: work(input) = work(output), =100%. Energy: The property of a system that enables it to do work. Conservation o. E.: Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes. Equilibrium: The state of an object when not acted upon by a net force or net torque; an object in equilibrium may be at rest or moving at uniform velocity - not accelerating. Mechanical E.: The state of an object or system of objects for which any impressed forces cancels to zero and no acceleration occurs. Dynamic E.: Object is moving without experiencing acceleration. Static E.: Object is at rest.F Force: The influence that can cause an object to be accelerated or retarded; is always in the direction of the net force, hence a vector quantity; the four elementary forces are: Electromagnetic F.: Is an attraction or repulsion G, gravit. const.6.672E-11[Nm2/kg2] between electric charges: d, distance [m] 2 2 2 2 F = 1/(40) (q1q2/d ) [(CC/m )(Nm /C )] = [N] m,M, mass [kg] Gravitational F.: Is a mutual attraction between all masses: q, charge [As] [C] 2 2 2 2 F = GmM/d [Nm /kg kg 1/m ] = [N] 0, dielectric constant Strong F.: (nuclear force) Acts within the nuclei of atoms: 8.854E-12 [C2/Nm2] [F/m] 2 2 2 2 2 F = 1/(40) (e /d ) [(CC/m )(Nm /C )] = [N] , 3.14 [-] Weak F.: Manifests itself in special reactions among elementary e, 1.60210 E-19 [As] [C] particles, such as the reaction that occur in radioactive decay. -
Probing Pulse Structure at the Spallation Neutron Source Via Polarimetry Measurements
University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 5-2017 Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements Connor Miller Gautam University of Tennessee, Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Nuclear Commons Recommended Citation Gautam, Connor Miller, "Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements. " Master's Thesis, University of Tennessee, 2017. https://trace.tennessee.edu/utk_gradthes/4741 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Connor Miller Gautam entitled "Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Physics. Geoffrey Greene, Major Professor We have read this thesis and recommend its acceptance: Marianne Breinig, Nadia Fomin Accepted for the Council: Dixie L. Thompson Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements A Thesis Presented for the Master of Science Degree The University of Tennessee, Knoxville Connor Miller Gautam May 2017 c by Connor Miller Gautam, 2017 All Rights Reserved. -
CHEM 1412. Chapter 21. Nuclear Chemistry (Homework) Ky
CHEM 1412. Chapter 21. Nuclear Chemistry (Homework) Ky Multiple Choice Identify the choice that best completes the statement or answers the question. ____ 1. Consider the following statements about the nucleus. Which of these statements is false? a. The nucleus is a sizable fraction of the total volume of the atom. b. Neutrons and protons together constitute the nucleus. c. Nearly all the mass of an atom resides in the nucleus. d. The nuclei of all elements have approximately the same density. e. Electrons occupy essentially empty space around the nucleus. ____ 2. A term that is used to describe (only) different nuclear forms of the same element is: a. isotopes b. nucleons c. shells d. nuclei e. nuclides ____ 3. Which statement concerning stable nuclides and/or the "magic numbers" (such as 2, 8, 20, 28, 50, 82 or 128) is false? a. Nuclides with their number of neutrons equal to a "magic number" are especially stable. b. The existence of "magic numbers" suggests an energy level (shell) model for the nucleus. c. Nuclides with the sum of the numbers of their protons and neutrons equal to a "magic number" are especially stable. d. Above atomic number 20, the most stable nuclides have more protons than neutrons. e. Nuclides with their number of protons equal to a "magic number" are especially stable. ____ 4. The difference between the sum of the masses of the electrons, protons and neutrons of an atom (calculated mass) and the actual measured mass of the atom is called the ____. a. isotopic mass b. -
Nuclear Models: Shell Model
LectureLecture 33 NuclearNuclear models:models: ShellShell modelmodel WS2012/13 : ‚Introduction to Nuclear and Particle Physics ‘, Part I 1 NuclearNuclear modelsmodels Nuclear models Models with strong interaction between Models of non-interacting the nucleons nucleons Liquid drop model Fermi gas model ααα-particle model Optical model Shell model … … Nucleons interact with the nearest Nucleons move freely inside the nucleus: neighbors and practically don‘t move: mean free path λ ~ R A nuclear radius mean free path λ << R A nuclear radius 2 III.III. ShellShell modelmodel 3 ShellShell modelmodel Magic numbers: Nuclides with certain proton and/or neutron numbers are found to be exceptionally stable. These so-called magic numbers are 2, 8, 20, 28, 50, 82, 126 — The doubly magic nuclei: — Nuclei with magic proton or neutron number have an unusually large number of stable or long lived nuclides . — A nucleus with a magic neutron (proton) number requires a lot of energy to separate a neutron (proton) from it. — A nucleus with one more neutron (proton) than a magic number is very easy to separate. — The first exitation level is very high : a lot of energy is needed to excite such nuclei — The doubly magic nuclei have a spherical form Nucleons are arranged into complete shells within the atomic nucleus 4 ExcitationExcitation energyenergy forfor magicm nuclei 5 NuclearNuclear potentialpotential The energy spectrum is defined by the nuclear potential solution of Schrödinger equation for a realistic potential The nuclear force is very short-ranged => the form of the potential follows the density distribution of the nucleons within the nucleus: for very light nuclei (A < 7), the nucleon distribution has Gaussian form (corresponding to a harmonic oscillator potential ) for heavier nuclei it can be parameterised by a Fermi distribution. -
Arxiv:1901.01410V3 [Astro-Ph.HE] 1 Feb 2021 Mental Information Is Available, and One Has to Rely Strongly on Theoretical Predictions for Nuclear Properties
Origin of the heaviest elements: The rapid neutron-capture process John J. Cowan∗ HLD Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019, USA Christopher Snedeny Department of Astronomy, University of Texas, 2515 Speedway, Austin, TX 78712-1205, USA James E. Lawlerz Physics Department, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706-1390, USA Ani Aprahamianx and Michael Wiescher{ Department of Physics and Joint Institute for Nuclear Astrophysics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556, USA Karlheinz Langanke∗∗ GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany and Institut f¨urKernphysik (Theoriezentrum), Fachbereich Physik, Technische Universit¨atDarmstadt, Schlossgartenstraße 2, 64298 Darmstadt, Germany Gabriel Mart´ınez-Pinedoyy GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany; Institut f¨urKernphysik (Theoriezentrum), Fachbereich Physik, Technische Universit¨atDarmstadt, Schlossgartenstraße 2, 64298 Darmstadt, Germany; and Helmholtz Forschungsakademie Hessen f¨urFAIR, GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany Friedrich-Karl Thielemannzz Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland and GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany (Dated: February 2, 2021) The production of about half of the heavy elements found in nature is assigned to a spe- cific astrophysical nucleosynthesis process: the rapid neutron capture process (r-process). Although this idea has been postulated more than six decades ago, the full understand- ing faces two types of uncertainties/open questions: (a) The nucleosynthesis path in the nuclear chart runs close to the neutron-drip line, where presently only limited experi- arXiv:1901.01410v3 [astro-ph.HE] 1 Feb 2021 mental information is available, and one has to rely strongly on theoretical predictions for nuclear properties. -
Interaction of Neutrons with Matter
Interaction of Neutrons With Matter § Neutrons interactions depends on energies: from > 100 MeV to < 1 eV § Neutrons are uncharged particles: Þ No interaction with atomic electrons of material Þ interaction with the nuclei of these atoms § The nuclear force, leading to these interactions, is very short ranged Þ neutrons have to pass close to a nucleus to be able to interact ≈ 10-13 cm (nucleus radius) § Because of small size of the nucleus in relation to the atom, neutrons have low probability of interaction Þ long travelling distances in matter See Krane, Segre’, … While bound neutrons in stable nuclei are stable, FREE neutrons are unstable; they undergo beta decay with a lifetime of just under 15 minutes n ® p + e- +n tn = 885.7 ± 0.8 s ≈ 14.76 min Long life times Þ before decaying possibility to interact Þ n physics … x Free neutrons are produced in nuclear fission and fusion x Dedicated neutron sources like research reactors and spallation sources produce free neutrons for the use in irradiation neutron scattering exp. 33 N.B. Vita media del protone: tp > 1.6*10 anni età dell’universo: (13.72 ± 0,12) × 109 anni. beta decay can only occur with bound protons The neutron lifetime puzzle From 2016 Istitut Laue-Langevin (ILL, Grenoble) Annual Report A. Serebrov et al., Phys. Lett. B 605 (2005) 72 A.T. Yue et al., Phys. Rev. Lett. 111 (2013) 222501 Z. Berezhiani and L. Bento, Phys. Rev. Lett. 96 (2006) 081801 G.L. Greene and P. Geltenbort, Sci. Am. 314 (2016) 36 A discrepancy of more than 8 seconds !!!! https://www.scientificamerican.com/article/neutro -
Mass Defect & Binding Energy the Nuclear Reaction Used by Stars To
Mass Defect & Binding Energy The nuclear reaction used by stars to produce energy (for most of their lives anyway) is the proton proton cycle: 1H + 1H → 2H + e– + ν 1H + 2H → 3He + γ 1H + 3He → 4He + e– + ν or 3He + 3He → 4He + 1H + 1H In the overall reaction, 4 hydrogen-1 atoms combine to form 1 He-4 atom plus some other parti- cles and energy. But examining the atomic masses of hydrogen and helium on the periodic table, the mass of four hydrogen atoms is greater than the mass of one helium atom. Subtracting the dif- ference gives: 4 × 1.007825 – 4.002603 = 0.028697 amu This difference is called the mass defect and measures the amount of “binding energy” stored in an atom’s nucleus or the amount of energy required to break up the nucleus back into the individ- ual protons and neutrons. In general, the mass defect is calculated by summing the mass of protons, neutrons, and electrons in an atom, and subtracting the atom’s actual atomic mass. The general formula is: Md = Z mp + N mn - Ma where Z is the atomic number, N is the number of neutrons in the atom, and Ma is the actual mea- sured mass of the atom. Placing Md into Einstein's equation for relating mass and energy gives the energy release from forming the atom from its constituent particles: 2 E = Md c where c is the speed of light (≈ 3.00 × 108 m/s). For example, using the information from the reac- tion above, one can deduce that to form 1 kg of 4He from requires 1.0073 kg of 1H. -
14. Structure of Nuclei Particle and Nuclear Physics
14. Structure of Nuclei Particle and Nuclear Physics Dr. Tina Potter Dr. Tina Potter 14. Structure of Nuclei 1 In this section... Magic Numbers The Nuclear Shell Model Excited States Dr. Tina Potter 14. Structure of Nuclei 2 Magic Numbers Magic Numbers = 2; 8; 20; 28; 50; 82; 126... Nuclei with a magic number of Z and/or N are particularly stable, e.g. Binding energy per nucleon is large for magic numbers Doubly magic nuclei are especially stable. Dr. Tina Potter 14. Structure of Nuclei 3 Magic Numbers Other notable behaviour includes Greater abundance of isotopes and isotones for magic numbers e.g. Z = 20 has6 stable isotopes (average=2) Z = 50 has 10 stable isotopes (average=4) Odd A nuclei have small quadrupole moments when magic First excited states for magic nuclei higher than neighbours Large energy release in α, β decay when the daughter nucleus is magic Spontaneous neutron emitters have N = magic + 1 Nuclear radius shows only small change with Z, N at magic numbers. etc... etc... Dr. Tina Potter 14. Structure of Nuclei 4 Magic Numbers Analogy with atomic behaviour as electron shells fill. Atomic case - reminder Electrons move independently in central potential V (r) ∼ 1=r (Coulomb field of nucleus). Shells filled progressively according to Pauli exclusion principle. Chemical properties of an atom defined by valence (unpaired) electrons. Energy levels can be obtained (to first order) by solving Schr¨odinger equation for central potential. 1 E = n = principle quantum number n n2 Shell closure gives noble gas atoms. Are magic nuclei analogous to the noble gas atoms? Dr. -
1663-29-Othernuclearreaction.Pdf
it’s not fission or fusion. It’s not alpha, beta, or gamma dosimeter around his neck to track his exposure to radiation decay, nor any other nuclear reaction normally discussed in in the lab. And when he’s not in the lab, he can keep tabs on his an introductory physics textbook. Yet it is responsible for various experiments simultaneously from his office computer the existence of more than two thirds of the elements on the with not one or two but five widescreen monitors—displaying periodic table and is virtually ubiquitous anywhere nuclear graphs and computer codes without a single pixel of unused reactions are taking place—in nuclear reactors, nuclear bombs, space. Data printouts pinned to the wall on the left side of the stellar cores, and supernova explosions. office and techno-scribble densely covering the whiteboard It’s neutron capture, in which a neutron merges with an on the right side testify to a man on a mission: developing, or atomic nucleus. And at first blush, it may even sound deserving at least contributing to, a detailed understanding of complex of its relative obscurity, since neutrons are electrically neutral. atomic nuclei. For that, he’ll need to collect and tabulate a lot For example, add a neutron to carbon’s most common isotope, of cold, hard data. carbon-12, and you just get carbon-13. It’s slightly heavier than Mosby’s primary experimental apparatus for doing this carbon-12, but in terms of how it looks and behaves, the two is the Detector for Advanced Neutron Capture Experiments are essentially identical. -
Nuclear Physics: the ISOLDE Facility
Nuclear physics: the ISOLDE facility Lecture 1: Nuclear physics Magdalena Kowalska CERN, EP-Dept. [email protected] on behalf of the CERN ISOLDE team www.cern.ch/isolde Outline Aimed at both physics and non-physics students This lecture: Introduction to nuclear physics Key dates and terms Forces inside atomic nuclei Nuclear landscape Nuclear decay General properties of nuclei Nuclear models Open questions in nuclear physics Lecture 2: CERN-ISOLDE facility Elements of a Radioactive Ion Beam Facility Lecture 3: Physics of ISOLDE Examples of experimental setups and results 2 Small quiz 1 What is Hulk’s connection to the topic of these lectures? Replies should be sent to [email protected] Prize: part of ISOLDE facility 3 Nuclear scale Matter Crystal Atom Atomic nucleus Macroscopic Nucleon Quark Angstrom Nuclear physics: femtometer studies the properties of nuclei and the interactions inside and between them 4 and with a matching theoretical effort theoretical a matching with and facilities experimental dedicated many with better and better it know to getting are we but Today Becquerel, discovery of radioactivity Skłodowska-Curie and Curie, isolation of radium : the exact form of the nuclear interaction is still not known, known, not still is interaction of nuclearthe form exact the : Known nuclides Known Chadwick, neutron discovered History 5 Goeppert-Meyer, Jensen, Haxel, Suess, nuclear shell model first studies on short-lived nuclei Discovery of 1-proton decay Discovery of halo nuclei Discovery of 2-proton decay Calculations with -
Spontaneous Fission
13) Nuclear fission (1) Remind! Nuclear binding energy Nuclear binding energy per nucleon V - Sum of the masses of nucleons is bigger than the e M / nucleus of an atom n o e l - Difference: nuclear binding energy c u n r e p - Energy can be gained by fusion of light elements y g r e or fission of heavy elements n e g n i d n i B Mass number 157 13) Nuclear fission (2) Spontaneous fission - heavy nuclei are instable for spontaneous fission - according to calculations this should be valid for all nuclei with A > 46 (Pd !!!!) - practically, a high energy barrier prevents the lighter elements from fission - spontaneous fission is observed for elements heavier than actinium - partial half-lifes for 238U: 4,47 x 109 a (α-decay) 9 x 1015 a (spontaneous fission) - Sponatenous fission of uranium is practically the only natural source for technetium - contribution increases with very heavy elements (99% with 254Cf) 158 1 13) Nuclear fission (3) Potential energy of a nucleus as function of the deformation (A, B = energy barriers which represent fission barriers Saddle point - transition state of a nucleus is determined by its deformation - almost no deformation in the ground state - fission barrier is higher by 6 MeV Ground state Point of - tunneling of the barrier at spontaneous fission fission y g r e n e l a i t n e t o P 159 13) Nuclear fission (4) Artificially initiated fission - initiated by the bombardment with slow (thermal neutrons) - as chain reaction discovered in 1938 by Hahn, Meitner and Strassmann - intermediate is a strongly deformed -
Production and Properties Towards the Island of Stability
This is an electronic reprint of the original article. This reprint may differ from the original in pagination and typographic detail. Author(s): Leino, Matti Title: Production and properties towards the island of stability Year: 2016 Version: Please cite the original version: Leino, M. (2016). Production and properties towards the island of stability. In D. Rudolph (Ed.), Nobel Symposium NS 160 - Chemistry and Physics of Heavy and Superheavy Elements (Article 01002). EDP Sciences. EPJ Web of Conferences, 131. https://doi.org/10.1051/epjconf/201613101002 All material supplied via JYX is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. EPJ Web of Conferences 131, 01002 (2016) DOI: 10.1051/epjconf/201613101002 Nobel Symposium NS160 – Chemistry and Physics of Heavy and Superheavy Elements Production and properties towards the island of stability Matti Leino Department of Physics, University of Jyväskylä, PO Box 35, 40014 University of Jyväskylä, Finland Abstract. The structure of the nuclei of the heaviest elements is discussed with emphasis on single-particle properties as determined by decay and in- beam spectroscopy. The basic features of production of these nuclei using fusion evaporation reactions will also be discussed. 1. Introduction In this short review, some examples of nuclear structure physics and experimental methods relevant for the study of the heaviest elements will be presented.